surgical technique

An orthopaedic surgeon makes a modification to an operative approach for total knee arthroplasty. After he has completed 25 cases, he stops and reviews his patient outcomes. He publishes the data. What level of evidence is supplied by this type of data?

A.II

B.IV

C.III

D.V

E.I

Case series that are non randomised and lack concurrent controls at best supply level IV evidence only. To qualify for level I and II evidence a prospective randomised controlled trial with appropriate blinding, control matching and power calculations is needed.

Levels of evidence

The level of evidence refers to the study design used by investigators to minimise bias.

Level of evidence

Source

IEvidence obtained from systematic review of all relevant randomised controlled trials

IIEvidence derived from at least one properly designed randomised controlled trial

IIIEvidence derived from well designed pseudo-randomised controlled trials (e.g. alternate allocation) or historical controls

IVEvidence derived from case series or case reportsVPanel or expert opinion

Many of the categories contain sub groups, detailed knowledge of these are not required for MRCS Part A.Theme: Use of suture materials and closure devices

A.Silk 3/0B.Polyglactin 3/0C.Polydioxanone 1/0D.Stainless steel skin clipsE.Stainless steel wire 1/0F.6/0 PolypropyleneG.3/0 Undyed polyglactin

H.Polypropylene 3/0

Please select the most appropriate suture material for the situation described. Each option may be used once, more than once or not at all.

2. Mass closure of abdominal wall following elective right hemicolectomy through a midline incision.

Polydioxanone 1/0

PDS or polydioxanone is the ideal suture material. Non absorbable sutures have higher incidence of incisional herniae.

3. Closure of the sternum following coronary artery bypass grafting.

Stainless steel wire 1/0

Stainless steel wire is typically used.

4. Application of vein patch to femoral artery following endarterectomy.

6/0 Polypropylene

Polypropylene is the suture of choice. Fine sutures are preferred.

Suture material

Suture materialsAgentClassificationDurabilityUsesSpecial pointsSilkBraided

BiologicalTheoretically permanent although strength not preserved

Anchoring devices, skin closure

Knots easily, poor cosmesis

CatgutBraidedBiological

5-7 daysShort term wound approximation

Poor cosmesisDegrades rapidlyNot available in UK

Chromic catgutBraidedBiological

Up to 12 weeksApposition of deeply sited tissues

Unpredictable degradation patternNot in use in UK

Polydiaxonone (PDS)

Synthetic Monofilament

Up to 3 months (longer with thicker sutures)

Widespread surgical applications including visceral anastomoses, dermal closure, mass closure of abdominal wall

Used in most surgical specialties (avoid dyed form in dermal closure)

Polyglycolic acid (Vicryl, Dexon)

Braided Synthetic

Up to 6 weeksMost tissues can be apposed using polyglycolic acid

It has good handling properties, the dyed form of this suture should not be used for skin closure

Polypropylene (Prolene)


PermanentWidely used, agent of choice for vascular anastomoses

Poor handling properties

Polyester (Ethibond)

Synthetic Braided

PermanentIts combination of permanency and braiding makes it useful for laparoscopic surgery

It is more expensive and has considerable tissue drag

Absorbable vs Non absorbable

Time taken to degrade absorbable materials varies Usually by macrophages hydrolysing material Consider absorbable sutures in situations where long term tissue apposition is

not required. In cardiac and vascular surgery non absorbable sutures are usually used.

Suture size

The higher the index number the smaller the suture i.e. : 6/0 prolene is finer than 1/0 prolene.

Finer sutures have less tensile strength. For example 6/0 prolene would not be a suture suitable for abdominal mass closure but would be ideal for small calibre distal arterial anastomoses.

Braided vs monofilamentGenerally speaking braided sutures have better handling characteristics than non braided. However, they are associated with higher bacterial counts. Braided materials are unsuitable for use in vascular surgery as they are potentially thrombogenic.Which of the following visceral anastomoses has the lowest risk of anastomotic leak? You may assume that all are constructed in ideal circumstances.

A.Stapled ileocolic anastomosis

B.Hand sewn anastomosis of the proximal ileum

C.Stapled colorectal anastomosis defunctioned with loop ileostomy

D.Stapled colorectal anastomosis defunctioned with loop colostomy

E.Hand sewn oesophagojejunal anastomosis

Rectal and oesophageal surgery have some the highest risk of anastomotic leakage, rates following anterior resection are quoted to be up to 10%. Small bowel anastomoses are the most technically forgiving. Factors increasing the risk of anastamotic leakage include previous irradiation, sepsis, malnutrition, poor blood supply and poor technique.The defunctioning of rectal anastomoses may reduce the clinical impact of anastomotic leak and make it amenable to percutaneous drainage, but does not necessarily reduce the incidence of leaks themselves.

Anastomoses

A wide variety of anastomoses are constructed in surgical practice. Essentially the term refers to the restoration of luminal continuity. As such they are a feature of both abdominal and vascular surgery.

Visceral anastomoses

For an anastomosis to heal three criteria need to be fulfilled:

Adequate blood supply Mucosal apposition Minimal tension

When these are compromise the anastomosis may dehisce (leak). Even in the best surgical hands some anastomoses are more prone to dehiscence than others. Oesophageal and rectal anastomoses are more prone to leakage and reported leak rates following oesophageal and rectal surgery can be as high as 20%. This figure includes radiological leaks and those with a clinically significant leak will be of a lower order of magnitude. As a rule small bowel anastomoses heal most reliably.

The decision as to how best to achieve mucosal apposition is one for each surgeon. Some will prefer the use of stapling devices as they are quicker to use, others will prefer to perform a sutured anastomosis. The attention to surgical technique is more important than the method chosen and a poorly constructed stapled anastomosis in thickened tissue is far more prone to leakage than a hand sewn anastomosis in the

same circumstances.

If an anastomosis looks unsafe then it may be best not to construct one at all. In colonic surgery this is relatively clear cut and most surgeons would bring out an end colostomy. In situations such as oesophageal surgery this is far more problematic and colonic interposition may be required in this situation.

Vascular anastomoses

Most arterial surgery involving bypasses or aneurysm repairs will require construction of an arterial anastomosis. Technique is important and for small diameter distal arterial surgery the intimal hyperplasia resulting from a badly constructed anastomosis may render the whole operation futile before the patient leaves hospital.

Some key points about vascular anastomoses:

Always use non absorbable monofilament suture (e.g. Polypropylene). Round bodied needle. Correct size for anastamosis ( i.e. 6/0 prolene for bottom end of a femoro-

distal bypass). Suture should be continuous and from inside to outside of artery to avoid

raising an intimal flap.

Theme: Management of skin wounds

A.Immediate split thickness skin graftB.Delayed split thickness skin graftC.Primary closureD.Delayed primary closureE.Compression bandagesF.Myocutaneous flapG.Random free flap

For each of the following injury scenarios please select the most appropriate management. Each option may be used once, more than once or not at all.

6. A 63 year old male is gardening when he trips and lands on a scythe. He sustains a deep laceration of his lateral thigh, it measures 3cm depth by 7cm length, it penetrates down to the bone, but no fracture is evident on imaging or examination. His co- morbidities include type II diabetes mellitus (diet controlled) and polymyalgia rheumatica (takes regular low dose prednisolone).

Delayed primary closure

Theme from September 2012 ExamWounds which are contaminated or have the potential to become so are unsafe for immediate primary closure. The combination of diabetes and steroids makes

wound complications more likely. Despite his high risk a primary skin graft or flap is unlikely to be a safer option. Either may be used at a later date in the event that delayed primary closure is unsuccessful.

7. A 71 year old lady trips over and falls landing on her left skin. She sustains a large pretibial laceration of her leg.

You answered Myocutaneous flap

The correct answer is Immediate split thickness skin graft

Pretibial lacerations do not heal well. Simple apposition of skin edges almost always fails due to poor quality dermal tissues and underlying haematoma. Debridement a primary grafting usually gives the best results.

8. A 73 year old lady presents with an ulcer overlying her medial malleolus. It is painless and has been present for 4 months. She has oedema of the lower limbs and her ABPI measures 0.9.

You answered Immediate split thickness skin graft

The correct answer is Compression bandages

This is likely to be a venous leg ulcer. These are typically managed using compression bandages. Contra indications to this technique include peripheral vascular disease (not present here).

Methods of wound closure

Method of closure

Indication

Primary closure Clean wound, usually surgically created or following minor trauma

Standard suturing methods will usually suffice Wound heals by primary intention

Delayed primary closure

Similar methods of actual closure to primary closure May be used in situations where primary closure is either not

achievable or not advisable e.g. infection

Vacuum assisted closure

Uses negative pressure therapy to facilitate wound closure Sponge is inserted into wound cavity and then negative

pressure applied

Advantages include removal of exudate and versatility Disadvantages include cost and risk of fistulation if used

incorrectly on sites such as bowel

Split thickness skin grafts

Superficial dermis removed with Watson knife or dermatome (commonly from thigh)

Remaining epithelium regenerates from dermal appendages Coverage may be increased by meshing

Full thickness skin grafts

Whole dermal thickness is removed Sub dermal fat is then removed and graft placed over donor

site Better cosmesis and flexibility at recipient site Donor site "cost"

Flaps Viable tissue with a blood supply May be pedicled or free Pedicled flaps are more reliable, but limited in range Free flaps have greater range but carry greater risk of

breakdown as they require vascular anastomosis

Theme: Surgical energy devices

A.Monopolar diathermyB.Bipolar diathermyC.CUSA deviceD.Argon plasma coagulation deviceE.Ligasure deviceF.Monopolar device in cutting modeG.Monopolar device in coagulation modeH.Monopolar device in blend mode

Please select the most appropriate surgical energy device for the procedure described. Each option may be used once, more than once or not at all.

9. Posterior dissection of the thyroid gland during total thyroid lobectomy

You answered Monopolar diathermy

The correct answer is Bipolar diathermy

This will minimise thermal trauma to the recurrent laryngeal nerve

10. Undertaking a snare polypectomy for a villous adenoma of the descending colon

You answered Ligasure device

The correct answer is Monopolar device in blend mode

Blend applies a mixture of coagulation and cutting modes to achieve smooth polypectomy

11. Dissection of temporal lobe for tumour

You answered Bipolar diathermy

The correct answer is CUSA device

The ultrasonic dissector is the preferred tool for this. It is also extensively used in liver resections

Diathermy

Diathermy devices are used by surgeons in all branches of surgery. Use electric currents to produce local heat and thereby facilitate haemostasis

or surgical dissection. Consist of a generator unit that is located outside the patient and can be set to

the level of power required by the surgeon. There are two major types of diathermy machine;

MonopolarThe current flows through the diathermy unit into a handheld device that is controlled by the surgeon. Electricity can flow from the tip of the device into the patient. The earth electrode is located some distance away. The relatively narrow tip of the diathermy device produces local heat and this can be used to vaporise and fulgurate tissues. The current can be adjusted in terms of frequency so that different actions can be effected. In cutting mode sufficient power is applied to the tissues to vaporise their water content. In coagulation mode the power level is reduced so that a coagulum is formed instead. Some diathermy machines can utilise a setting known as blend that alternates cutting and coagulation functions, these tend to be used during procedures such as colonoscopic polypectomy.

BipolarThe electric current flows from one electrode to another however, both electrodes are usually contained within the same device e.g. a pair of forceps. The result is that heating is localised to the area between the two electrodes and surrounding tissue damage is minimised.

Ultrasound based devicesThese include CUSA and Harmonic scalpel. They generate high frequency oscillations that seal and coagulate tissues. They have different energy settings that allow them to dissect and simultaneously seal vessels if required. The CUSA device leaves vessels intact that may then be divided.

Ligasure deviceDelivers tailored energy levels to allows simultaneous haemostasis and dissection. The device senses the impedance of the tissues and tailors energy levels accordingly.

Hazards of diathermy

Inadvertent patient burn. This may result of careless handling of the device or in the case of monopolar devices forgetting to apply a return electrode plate, In this situation patients may develop a contact burn when electricity flows to earth

Explosion or fire. This may occur when volatile anaesthetic gases or skin preparation fluid have been used

heme: Surgical drains

A.Redivac suction drainB.Corrugated drainC.Wallace Robinson drain (non suction)D.Penrose tubingE.Latex T Tube drainF.Silastic T Tube drainG.No drain

Please select the most appropriate surgical drainage system for the indication given. Each option may be used once, more than once or not at all.

1. A 56 year old lady undergoes and open cholecystectomy and exploration of common bile duct. The bile duct is closed over a drain.

Latex T Tube drain

This will elicit a fibrotic response and encourage a track to form.

2. A 48 year old lady undergoes a mastectomy and axillary node clearance for an invasive ductal cancer of the breast with lymph node metastasis.

You answered Corrugated drain

The correct answer is Redivac suction drain

The raw tissue exposed from the mastectomy site will often ooze serous fluid and may result in seroma formation when the drain is removed.

3. A 75 year old man undergoes a Hartman's procedure for sigmoid diverticular disease with pericolic abscess and colovesical fistula.

Wallace Robinson drain (non suction)

A non suction drain is the preferred option here.

Surgical drains

Drains are inserted in many surgical procedures and are of many types. As a broad rule they can be divided into those using suction and those which

do not. The diameter of the drain will depend upon the substance being drained, for

example smaller lumen drain for pneumothoraces vs haemothorax. Drains can be associated with complications and these begin with insertion

when there may be iatrogenic damage. When in situ they serve as a route for infections. In some specific situations they may cause other complications, for example suction drains left in contact with bowel for long periods may carry a risk of inducing fistulation.

Drains should be inserted for a defined purpose and removed once the need has passed.

A brief overview of types of drain and sites is given below

CNS

Low suction drain or free drainage systems may be used for situations such as drainage of sub dural haematomas.

CVS

Following cardiothoracic procedures of thoracic trauma underwater seal drains are often placed. These should be carefully secured. When an air leak is present they may be placed on suction whilst the air leak settles

Orthopaedics and trauma

In this setting drains are usually used to prevent haematoma formation (with associated risk of infection). Some orthopaedic drains may also be specially adapted to allow the drained blood to be auto transfused.

Gastro-intestinal surgery

Surgeons often place abdominal drains either to prevent or drain abscesses, or to turn an anticipated complication into one that can be easily controlled such as a bile leak following cholecystectomy. The type of drain used will depend upon the indication.

Drain typesType of drainFeaturesRedivac Suction type of drain

Closed drainage system High pressure vacuum system

Low pressure drainage systems

Consist of small systems such as the lantern style drain that may be used for short term drainage of small wounds and cavities

Larger systems are sometimes used following abdominal surgery, they have a lower pressure than the redivac system, which decreases the risks of fistulation

May be emptied and re-pressurised

Latex tube drains May be shaped (e.g. T Tube) or straight Usually used in non pressurised systems and act as sump

drains Most often used when it is desirable to generate fibrosis

along the drain trach (e.g. following exploration of the CBD)

Chest drains May be large or small diameter (depending on the indication)

Connected to underwater seal system to ensure one way flow of air

Corrugated drain Thin, wide sheet of plastic, usually soft Contains corrugations, along which fluids can track

Which of the following local anaesthetics is not an amino amide type?

A.Lignocaine

B.Xylocaine

C.Procaine

D.Bupivicaine

E.Prilocaine

All local anaesthetics have a chemical bond linking an amine to either an amide or an ester. Most local anaesthetics are of the amino- amide types, these have a more favorable side effect profile and are more stable in solution. Procaine and benzocaine have amino - ester groups, these are metabolised by pseudocholinesterases.

Local anaesthetic agents

Lidocaine

An amide Local anaesthetic and a less commonly used antiarrhythmic (affects Na

channels in the axon) Hepatic metabolism, protein bound, renally excreted Toxicity: due to IV or excess administration. Increased risk if liver

dysfunction or low protein states. Note acidosis causes lidocaine to detach from protein binding.

Drug interactions: Beta blockers, ciprofloxacin, phenytoin Features of toxicity: Initial CNS over activity then depression as lidocaine

initially blocks inhibitory pathways then blocks both inhibitory and activating pathways. Cardiac arrhythmias.

Increased doses may be used when combined with adrenaline to limit systemic absorption.

Cocaine

Pure cocaine is a salt, usually cocaine hydrochloride. It is supplied for local anaesthetic purposes as a paste.

It is supplied for clinical use in concentrations of 4 and 10%. It may be applied topically to the nasal mucosa. It has a rapid onset of action and has the additional advantage of causing marked vasoconstriction.

It is lipophillic and will readily cross the blood brain barrier. Its systemic effects also include cardiac arrhythmias and tachcardia.

Apart from its limited use in ENT surgery it is otherwise used rarely in mainstream surgical practice.

Bupivicaine

Bupivacaine binds to the intracellular portion of sodium channels and blocks sodium influx into nerve cells, which prevents depolarization.

It has a much longer duration of action than lignocaine and this is of use in that it may be used for topical wound infiltration at the conclusion of surgical procedures with long duration analgesic effect.

It is cardiotoxic and is therefore contra indicated in regional blockage in case the tourniquet fails.

The co-administration of adrenaline concentrates it at the site of action and allows the use of higher doses.

Prilocaine

Similar mechanism of action to other local anaesthetic agents. However, it is far less cardiotoxic and is therefore the agent of choice for intravenous regional anaesthesia e.g. Biers Block.

All local anaesthetic agents dissociate in tissues and this contributes to their therapeutic effect. The dissociation constant shifts in tissues that are acidic e.g. where an abscess is present and this reduce the efficacy.

Doses of local anaestheticsAgentDose plainDose with adrenalineLignocaine3mg/Kg7mg/KgBupivicane2mg/Kg2mg/KgPrilocaine6mg/Kg9mg/Kg

These are a guide only as actual doses depend on site of administration, tissue vascularity and co-morbidities.

ReferencesAn excellent review is provided by:French J and Sharp L. Local Anaesthetics. Ann R Coll Surg Engl 2012; 94: 76-80.Theme: Biological therapies

A.BevacizumabB.InfliximabC.TrastuzumabD.BasiliximabE.ImatinibF.Cetuximab

Please select the most appropriate biological agent for the situation described. Each option may be used once, more than once or not at all.

5. A 32 year old lady has previously undergone a wide local excision and axillary node clearance (5 nodes positive) for an invasive ductal carcinoma. It is oestrogen receptor negative, HER 2 positive, vascular invasion is present. She has a lesion suspicious for metastatic disease in the left lobe of her liver.

You answered Infliximab

The correct answer is Trastuzumab

This ladies young age, coupled with ER negativity and extensive nodal disease with suspicion of metastatic disease makes her a candidate for treatment with trastuzumab (herceptin).

6. A 22 year old lady has severe peri anal crohns disease with multiple anal fistulae, the acute sepsis has been drained and setons are in place. She is already receiving standard non biological therapy.

Infliximab

Infliximab is a popular choice in managing complex peri anal crohns. It is absolutely vital that all sepsis is drained prior to starting therapy.

7. A 63 year old man presents with a locally unresectable gastrointestinal stromal tumour. Biopsies confirm that it is KIT positive.

You answered Infliximab

The correct answer is Imatinib

Imatinib is licensed for treatment of GIST in the United Kingdom for this situation. The guidance from the National Institute of Clinical evidence is that patients be reviewed at 12 weeks after initiating therapy.

Biological agents

AgentsTargetUsesAdalimumabInfliximabEtanercept

TNF alpha inhibitorCrohns diseaseRheumatoid disease

BevacizumabAnti VEGF (anti angiogenic)Colorectal cancerRenalGlioblastoma

TrastuzumabHER receptorBreast cancerImatinibTyrosine kinase inhibitorGastrointestinal stromal tumours

Chronic myeloid leukaemiaBasiliximabIL2 binding siteRenal transplantsCetuximabEpidermal growth factor inhibitorEGF positive colorectal cancers

Detailed understanding of the actions of biological agents is well beyond the scope of

the MRCS syllabus. However, many of these drugs are being frequently encountered in surgical patients.Which of the following sutures has the largest diameter?

A.6/0 Polypropylene

B.5/0 Silk

C.3/0 Nylon

D.1 Polypropylene

E.0 Polydiaxone

The sizes of suture material are not related to the composition of the suture material.

Suture sizes

USP Suture size and corresponding suture diameterUSP SizeDiameter in mm11-00.0110-00.026-00.073-00.200.3510.4

Theme: Management of bleeding

A.Ligate vesselB.Underrun vesselC.Use of diathermyD.Application of surgicell E.Digital pressure

In each of the following scenarios the surgeon has encountered bleeding. Please select the most appropriate immediate management of the situation from the list below. Each option may be used once, more than once or not at all.

9. A 23 year old man is undergoing an open appendicectomy. The surgeons extend the incision medially and suddenly encounter troublesome bleeding.

You answered Use of diathermy

The correct answer is Ligate vessel

Theme from April 2012 ExamMedial extension of an appendicectomy incision carries the risk of injury to the inferior epigastric artery. This can bleed briskly and is best managed by ligation.

10. A 45 year old man is undergoing a laparotomy and following incision of the skin multiple bleeding points are identified in the dermis and sub dermal tissues.

You answered Digital pressure

The correct answer is Use of diathermy

Multiple bleeding points are best managed through the use of diathermy.

11. A 38 year old lady is undergoing a laparotomy when the surgeons damage the common iliac vein whilst commencing a pelvic dissection.

You answered Ligate vessel

The correct answer is Digital pressure

Major venous bleeding such as this should be controlled with digital pressure in the first instance. The definitive management will usually consist of suturing the defect closed with prolene sutures. Transection of the common iliac vein will necessitate a major venous reconstruction.

Management of bleeding

Bleeding is a process that is encountered in all branches of surgery. The decision as to how best to manage bleeding depends upon the site, vessel and circumstances.

Management of superficial dermal bleedingThis will usually cease spontaneously. If it is troublesome then direct use of monopolar or bipolar cautery devices will usually control the situation. Scalp wounds are a notable exception and the bleeding from these may be brisk. In this situation the use of mattress sutures as a wound closure method will usually address the problem.

Superficial arterial bleedingIf the vessel can be safely identified then the easiest method is to apply a haemostatic clip and ligate the vessel.

Major arterial bleeding

If the vessel can be clearly identified and is accessible then it may be possible to apply a clip and ligate the vessel. If the vessel is located in a pool of blood then blind application of haemostatic clips is highly dangerous and may result in collateral injury. In this situation evacuating the clot and packing the area is often safer. The pack can then be carefully removed when the required instruments are available. Some vessels may retract and bleeding may then be controlled by dissection of surrounding structures or under-running the bleeding point.

Major venous bleedingThe safest initial course of action is to apply digital pressure to the bleeding point. To control the bleeding the surgeon will need a working suction device. Divided veins may require ligation. Incomplete lacerations of major veins (e.g. IVC) are best repaired. In order to do this it is safest to apply a Satinsky type vascular clamp and repair the defect with 5/0 prolene.

Bleeding from raw surfacesThis may be mixed bleeding and can be troublesome. Spray diathermy and argon plasma coagulation are both useful agents. Certain topic haemostatic agents such as surgicell are useful in encouraging clot formation and may be used in conjunction with, or instead of, the above agents. A 7 year old boy is due to undergo a circumcision for phimosis. Which of the following devices would be the most appropriate agent to use for achieving haemostasis?

A.Monopolar unit in cutting mode

B.Bipolar unit

C.Monopolar unit in coagulation mode

D.Monopolar unit in blend mode

E.Monopolar unit configured to spray mode

The danger with the use of any source other than bipolar diathermy in this setting is the risk of causing trauma to end vessels. All the monopolar units, regardless of the setting will carry this risk.

Diathermy











If a 2 x 2 cm autologus skin graft is placed on an area of healthy granulation tissue, after about a week, a thin bluish - white margin appears around the graft and spreads at a rate of 1mm per day. What is it?

A.Epidermis alone

B.Epidermis and dermis

C.Dermis alone

D.Inflammatory exudate

E.Fibrin

This is the process of re-epithelialisation.

Wound healing

Surgical wounds are either incisional or excisional and either clean, clean contaminated or dirty. Although the stages of wound healing are broadly similar their contributions will vary according to the wound type.

The main stages of wound healing include:

Haemostasis

Vasospasm in adjacent vessels, platelet plug formation and generation of fibrin rich clot.

Inflammation

Neutrophils migrate into wound (function impaired in diabetes). Growth factors released, including basic fibroblast growth factor and vascular

endothelial growth factor. Fibroblasts replicate within the adjacent matrix and migrate into wound. Macrophages and fibroblasts couple matrix regeneration and clot substitution.

Regeneration

Platelet derived growth factor and transformation growth factors stimulate fibroblasts and epithelial cells.

Fibroblasts produce a collagen network. Angiogenesis occurs and wound resembles granulation tissue.

Remodeling

Longest phase of the healing process and may last up to one year (or longer). During this phase fibroblasts become differentiated (myofibroblasts) and these

facilitate wound contraction. Collagen fibres are remodeled. Microvessels regress leaving a pale scar.

The above description represents an idealised scenario. A number of diseases may distort this process. It is obvious that one of the key events is the establishing well vascularised tissue. At a local level angiogenesis occurs, but if arterial inflow and

venous return are compromised then healing may be impaired, or simply nor occur at all. The results of vascular compromise are all too evidence in those with peripheral vascular disease or those poorly constructed bowel anastomoses.

Conditions such as jaundice will impair fibroblast synthetic function and overall immunity with a detrimental effect in most parts of healing.

Problems with scars:

Hypertrophic scarsExcessive amounts of collagen within a scar. Nodules may be present histologically containing randomly arranged fibrils within and parallel fibres on the surface. The tissue itself is confined to the extent of the wound itself and is usually the result of a full thickness dermal injury. They may go on to develop contractures.

Image of hypertrophic scarring. Note that it remains confined to the boundaries of the original wound:

Image sourced from Wikipedia

Keloid scarsExcessive amounts of collagen within a scar. Typically a keloid scar will pass beyond the boundaries of the original injury. They do not contain nodules and may occur following even trivial injury. They do not regress over time and may recur following removal.

Image of a keloid scar. Note the extension beyond the boundaries of the original incision:

Image sourced from Wikipedia

Drugs which impair wound healing:

Non steroidal anti inflammatory drugs Steroids Immunosupressive agents Anti neoplastic drugs

ClosureDelayed primary closure is the anatomically precise closure that is delayed for a few days but before granulation tissue becomes macroscopically evident.

Secondary closure refers to either spontaneous closure or to surgical closure after granulation tissue has formed.Which of the following methods is most effective at destroying spores of the tubercle bacilli?

A.Immersion in 0.5% chlorhexidine in alcohol

B.Immersion in aqueous iodine

C.Heating in a hot air oven

D.Immersion in 0.1% sodium hypochlorite

E.Autoclaving

The tubercle bacilli has a waxy outer membrane that renders it more resistant to sterilisation and cleaning methods. Whilst 0.1% sodium hypochlorite will destroy may microbes it is less reliable in destroying tubercle bacilli. Hot air ovens provide less

reliable pathogen destruction than autoclaving, but may be indicated in situations where the equipment is sensitive to the autoclaving process. From the list of options above, autoclaving will most reliably destroy tubercle bacilli.

Sterilisation

Cleaning refers to removal of physical debris. Disinfection refers to reduction in numbers of viable organisms. Sterilisation is removal of all organisms and spores.

The method chosed depends upon the type of instrument and the procedure for which it will be used.

Sterilisation of surgical instruments typically takes place in an autoclave which uses pressurised steam at a temperature of 134 degrees. This method is reproducible and safe.

However, endoscopy equipment cannot be sterilised by this method as it would damage it. Therefore they are sterilised using 2% glutaraldehyde solution. Since staff may develop hypersensitivity its use is restricted to those pieces of equipment that cannot be sterilised by an alternative means.

In the industrial setting gamma irradiation is used.

Which of the following is a permanent suture material best suited for interrupted mattress dermal closure?

A.2/0 Polydiaxone

B.3/0 Polydiaxone

C.4/0 Polyglycolic acid

D.1/0 Dexon

E.3/0 Polypropylene

Of the sutures listed only prolene is a permanent suture material. It is a good agent for skin closure as it does not incite an inflammatory response and thus provides good cosmesis.

Suture material


BiologicalTheoretically permanent although



strength not preserved







Polydiaxonone (PDS)






Braided Synthetic








Synthetic Braided






Suture size



Braided vs monofilamentGenerally speaking braided sutures have better handling characteristics than non braided. However, they are associated with higher bacterial counts. Braided materials are unsuitable for use in vascular surgery as they are potentially thrombogenic.Theme: Surgical site infections

A.Glutaraldehyde 2% applied to the skinB.Sodium hypochlorite solution applied to the skinC.Aqueous iodine applied to the skinD.Perform surgery in a lamninar flow theatreE.Surgeon to wear exhaust suitF.Administration of clindamycinG.Administration of gentamicinH.Pre operative shaving

Please select the most appropriate modality to reduce the risk of developing a surgical site infection for the scenario given. Each option may be used once, more than once or not at all.

16. A 42 year old man is due to undergo a Mayo repair of a paraumbilical hernia. He is otherwise well.

You answered Pre operative shaving

The correct answer is Aqueous iodine applied to the skin

The patient will require skin preparation. However, use of glutaraldehyde or sodium hypochlorite would be an inappropriate choice. As the Mayo repair does not involve implantation of prosthetic mesh the use of antibiotics is not appropriate.

17. A 63 year old man with end stage oestoarthritis of the hip is due to undergo a total hip replacement. The skin has been prepared and antibiotics given.

You answered Aqueous iodine applied to the skin

The correct answer is Perform surgery in a lamninar flow theatre

Laminar flow is more important than an exhaust suit although use of both is ideal.

18. A 22 year old man is undergoing an appendicectomy. At operation there is copious pus around the appendix.

Administration of gentamicin

Gentamicin is the preferred agent. Clindamycin is associated with high rate of clostridium dificile infection.

Surgical site infection

Surgical site infections may occur following a breach in tissue surfaces and allow normal commensals and other pathogens to initiate infection. They are a major cause of morbidity and mortality.

Surgical site infections (SSI) comprise up to 20% of all healthcare associated infections and at least 5% of patients undergoing surgery will develop an SSI as a result.

In many cases the organisms are derived from the patient's own body. Measures that may increase the risk of SSI include:

Shaving the wound using a razor (disposable clipper preferred) Using a non iodine impregnated incise drape if one is deemed to be necessary Tissue hypoxia Delayed administration of prophylactic antibiotics in tourniquet surgery

Preoperatively

Don't remove body hair routinely If hair needs removal, use electrical clippers with single use head (razors

increase infection risk) Antibiotic prophylaxis if:

- placement of prosthesis or valve- clean-contaminated surgery- contaminated surgery

Use local formulary Aim to give single dose IV antibiotic on anaesthesia If a tourniquet is to be used, give prophylactic antibiotics earlier

Intraoperatively

Prepare the skin with alcoholic chlorhexidine (Lowest incidence of SSI) Cover surgical site with dressing

A recent meta analysis has confirmed that administration of supplementary oxygen does not reduce the risk of wound infection. In contrast to previous individual RCT's(1)

Post operativelyTissue viability advice for management of surgical wounds healing by secondary intention

Use of diathermy for skin incisionsIn the NICE guidelines the use of diathermy for skin incisions is not advocated(2). Several randomised controlled trials have been undertaken and demonstrated no increase in risk of SSI when diathermy is used(3).

References1. Brar M et al. Perioperative supplemental oxygen in colorectal patients: a meta analysis. J Surg Res 2011 (166): 227 -235. 2. http://www.nice.org.uk/CG743. Ahmad N and Ahmed A. Meta-analysis of the effectiveness of surgical scalpel or diathermy in making abdominal skin incisions. Ann Surg 2011, 253(1):8-13.Theme: Suture materials

A.Silk 3/0B.Polyglactin 3/0C.Polydiaxone 1/0D.Stainless steel skin clipsE.Stainless steel wire 1/0F.6/0 PolypropyleneG.3/0 Undyed polyglactinH.Polypropylene 3/0

Please select the most appropriate suture for the scenario given. Each option may be used once, more than once or not at all.

19. Anastomosis of ileum to transverse colon following right hemicolectomy.

Polyglactin 3/0

3/0 PDS would be an alternative, as would linear stapler but those are not in the list.

20. Distal anastomosis in a femorodistal bypass using vein.

6/0 Polypropylene

Arterial anastomoses should be constructed using polypropylene. In this case a fine suture material such as 6/0 is indicated.

21. Closure of skin following thyroidectomy for Graves disease.

You answered Polydiaxone 1/0

The correct answer is Stainless steel skin clips

Although some use sub cuticular stitches skin clips remain the standard of many. In the event of post operative haematoma causing respiratory obstruction, they are easier to remove.

Suture material











Polydiaxonone (PDS)






Braided Synthetic


It has good handling properties, the dyed form of this suture should not be used for skin

closurePolypropylene (Prolene)





Synthetic Braided






Suture size



Braided vs monofilamentGenerally speaking braided sutures have better handling characteristics than non braided. However, they are associated with higher bacterial counts. Braided materials are unsuitable for use in vascular surgery as they are potentially thrombogenic.Theme: Management of skin lesions

A.5mm punch biopsyB.Shave biopsyC.Excisional biopsyD.Wide excision of 5cmE.Tru cut biopsyF.Incisional biopsy

For the skin lesions described please select the most appropriate management option. Each option may be used once, more than once or not at all.

22. An 83 year old lady presents with multiple patches of pigmented irregular,

superficial lesions over the torso. They do not bleed but have become increasingly itchy.

You answered 5mm punch biopsy

The correct answer is Shave biopsy

Theme from April 2012 ExamThis is most likely to be seborrhoeic warts. These are usually superficially sited and are best managed with shave biopsy and cautery.

23. A 65 year old man presents with a 5cm ulcerated area over his medial malleolus.

You answered Wide excision of 5cm

The correct answer is 5mm punch biopsy

This is likely to be a venous ulcer and should usually be managed with compression bandaging if there is no arterial compromise. Long standing lesions may be complicated by the development of malignancy and for this reason a punch biopsy of long standing or non healing lesions is advisable.

24. A 23 year old lady presents with an itchy, bleeding pigmented lesion on her right thigh.

Excisional biopsy

This may represent a malignant melanoma. Complete excision is required to allow accurate histological assessment. If the diagnosis is confirmed then re-excision of margins may be required. Clearly if the lesion is benign then no further action is required.

Treatment of suspicious skin lesions

Skin lesions may be referred to surgeons for treatment or discovered incidentally. The table below outlines the various therapeutic options:

MethodIndicationTru-cut biopsy

Most often used for percutaneous sampling of deep seated lesions or used intra operatively for visceral lesions

5mm punch Used for diagnostic confirmation of lesions that are suspected to be

biopsybenign or where the definitive management is unlikely to be surgical. Of limited usefulness in pigmented lesions where they do not include sufficient tissue for accurate diagnosis. May be used in non melanoma type skin disease to establish diagnosis prior to more extensive resection.

Wide excision

Where the complete excision of the lesion (with healthy margins) is the main objective. In cosmetically sensitive sites, or where the defect is large, this may need to be complemented with plastic surgical techniques

Incisional biopsy

Used mainly for deep seated or extensive lesions where there is diagnostic doubt (usually following core or tru-cut biopsy). Used rarely for skin lesions.

Diagnostic excision

Primarily used for lesions that are suspicious for melanoma, the lesion is excised with a rim of normal tissue. Excision of margins may be required subsequently.Theme: Tissue sampling

A.Fine needle aspiration cytologyB.Surgical excision biopsyC.Smear cytologyD.Core cut biopsyE.Conventional surgical excisionF.Tru cut biopsyG.Punch biopsy

Please select the most appropriate sampling method for the situation given. Each option may be used once, more than once or not at all.

25. A 45 year old patient undergoes a CT scan of the abdomen and is noted to have a 6cm mass in the right adrenal gland. Urinary catecholamines and other endocrine investigations are negative. CT of the chest and remainder of the abdomen is otherwise normal.

You answered Fine needle aspiration cytology

The correct answer is Conventional surgical excision

Most surgeons would excise a mass of this size rather than attempt biopsy. Further information relating to adrenal masses is covered under this topic.

26. A 67 year old lady is suspected of having Pagets disease of the nipple

You answered Conventional surgical excision

The correct answer is Punch biopsy

This is a relatively clear indication for a punch biopsy. If cellular atypia is

present on punch biopsy then any in situ malignancy should be considered. FNAC would be unsuitable.

27. A 23 year old lady presents with a nodule in the right lobe of the thyroid. Examination of the neck is otherwise unremarkable and clinically she is euthyroid. Imaging shows a solid nodule at the site.

You answered Surgical excision biopsy

The correct answer is Fine needle aspiration cytology

FNAC is the first line investigation in this setting.Where as FNAC has declined in popularity recently, it remain a very popular option in the investigation of thyroid masses. It cannot reliably diagnose a follicular tumour.

Tissue sampling

Tissue sampling is an important surgical process. Biopsy modalities vary according to the site, experience and subsequent planned therapeutic outcome

The modalities comprise:-Fine needle aspiration cytology-Core biopsy-Excision biopsy-Tru cut biopsy-Punch biopsy -Cytological smears-Endoscopic or laparoscopic biopsy

When the lesion is superficial the decision needs to be taken as to whether complete excision is desirable or whether excision biopsy is acceptable. In malignant melanoma for example the need for safe margins will mean that a more radical surgical approach needs to be adopted after diagnostic confirmation from excision biopsy than would be the case in basal cell carcinoma. Punch biopsies are useful in gaining histological diagnosis of unclear skin lesions where excision biopsy is undesirable such as in establishing whether a skin lesion is vasculitic or not.

Fine needle aspiration cytology (FNAC) is an operator dependent procedure that may or may not be image guided and essentially involves passing a needle through a lesion whilst suction is applied to a syringe. The material thus obtained is expressed onto a slide and sent for cytological assessment. This test can be limited by operator inexperience and also by the lack of histological architectural information (e.g. Follicular carcinoma of the thyroid). Where a discharge is present a sample may be sent for cytology although in some sites (e.g. Nipple discharge ) the information gleaned may be meaningless.

Tissue samples may be obtained by both core and tru cut biopsy. A core biopsy is obtained by use of a spring loaded gun with a needle passing quickly through the lesion of interest. A tru cut biopsy achieves the same objective but the needle moved by hand. When performing these techniques image guidance may be desirable (e.g. In breast lesions). Consideration needs to be given to any planned surgical resection as it may be necessary to resect the biopsy tract along with the specimen (e.g. In sarcoma surgery).

Visceral lesions may be accessed percutaneously under image guidance such as ultrasound guided biopsy of liver metastases. Or under direct vision such as a colonoscopic biopsy.Theme: Management of wounds

A.Split thickness skin graftB.Full thickness skin graftC.Insertion of tissue expander at donor site and delayed split thickness

skin graftD.Myocutaneous flap reconstruction (pedicled)E.Direct primary closureF.Delayed primary closure

Please select the most appropriate management for the wound described. Each option may be used once, more than once or not at all.

28. A 34 year old man has a tissue defect measuring 3 cm by 1 cm following an excision of a lipoma from the scapula.

You answered Insertion of tissue expander at donor site and delayed split thickness skin graft

The correct answer is Direct primary closure

This wound should be amenable to primary closure. There is minimal associated tissue loss and the surgery is minor and uncontaminated.

29. A 72 year old lady has a 4cm basal cell carcinoma excised from her right cheek. There is a rhomboid defect measuring 4cm by 4cm.

You answered Myocutaneous flap reconstruction (pedicled)

The correct answer is Full thickness skin graft

Facial wounds that are large and irregularly shaped are best managed with full thickness skin grafts.

30. A 5 year old suffers 20% burns to the torso. On examination there is fixed pigmentation and the affected area has a white and dry appearance.

Split thickness skin graft

This is a full thickness burn and will require split thickness skin grafting. Meshing the graft may increase the donor site yield. However, this is at the expense of cosmesis.

Tissue reconstruction

Skin Grafts and Flaps

Skin flaps or grafts may be required where primary wound closure cannot be achieved or would entail either significant cosmetic defect or considerable functional disturbance as a result of wound contraction.

Reconstructive ladderMethodTypesDirect closureThe simplest option where possibleGrafting techniques Split thickness

Full thickness Skin Substitute Composite

Flap techniqueLocal:

Transposition Pivot Alphabetplasty (e.g. Z-Y)

Regional:

Myocutaneous Fasciocutaneous Neurocutaneous

Distant:

Free tissue transfer

Prelamination techniques

Allows creation of specialised flaps e.g. buccal mucosa

Tissue expansionInvolves placement of tissue expanders to increase amount of tissue at donor sites

Skin Grafts Vs. FlapsSkin GraftsFlapsNo size limit (Split)/ Relative size limit (full thickness)

Size limited by territory of blood supply

Rely on wound bed for blood supplyTissue has its own blood supplyTake better on clean well vascularised wound beds

Will survive independent of the wound bed

Split skin graft donor site typically heals in 12 days

Direct closure of donor site or secondary skin graft

Donor site may be reusedDonor site cannot be reused

Split thickness skin grafts

Available in range of thicknesses. Thigh is the commonest donor site Size may be increased by meshing the graft. However this comes with

compromise on cosmesis. Donor sites, especially if thin grafts are taken can be reused following re-

epithelialisation

Full thickness grafts

Most commonly used for facial reconstruction Include dermal appendages Provide superior cosmetic result

Composite graftsThese are grafts containing more than one tissue type, such as skin and fat. They are usually used to cover small defects in cosmetically important areas.

Flaps

Flaps have their own blood supply and may be pedicled or free. May have multiple components e.g. skin, skin + fat, skin + fat + muscle. They will have the ability to take regardless of the underlying tissue bed. The type of intrinsic blood supply is important. For example in breast surgery

pedicled latissimus dorsi flaps will be less prone to failure than microsvascular anastomosed free Diep flaps.

You have just completed a laparotomy for peritonitis due to a perforated peptic ulcer. What is the best surgical strategy for avoidance of a complete abdominal wound dehisence?

A.Use of skin clips to close the skin rather than sub cuticular sutures

B.Careful approximation of the peritonum with non absorbable sutures

C.Mass closure of the midline wound using a 1/0 polydiaxone suture

D.Direct apposition of the rectus muscle rather than linea alba aponeurosis

E.Mass closure of the midline wound using a 3/0 polypropylene suture

The incidence of post operative wound dehisence is minimise by following Jenkins rule which advocates mass closure of the midline wound. However, the suture strength is an important consideration and 3/0 sutures do not have sufficient tensile strength. Both polydiaxone (PDS) and polypropylene (Prolene) or nylon (Ethilon) are all equally suitable. Although separate closure of the peritoneum was practised it has no bearing on the incidence of abdominal wound dehisence.

Abdominal wound dehiscence

This is a significant problem facing all surgeons who undertake abdominal surgery on a regular basis. Traditionally it is said to occur when all layers of an abdominal mass closure fail and the viscera protrude externally (associated with 30% mortality).

It can be subdivided into superficial, in which the skin wound alone fails and complete, implying failure of all layers.

Factors which increase the risk are:* Malnutrition* Vitamin deficiencies * Jaundice * Steroid use * Major wound contamination (e.g. faecal peritonitis)* Poor surgical technique (Mass closure technique is the preferred method-Jenkins Rule)

When sudden full dehiscence occurs the management is as follows:* Analgesia* Intravenous fluids* Intravenous broad spectrum antibiotics* Coverage of the wound with saline impregnated gauze (on the ward)* Arrangements made for a return to theatre

Surgical strategy

Correct the underlying cause (eg TPN or NG feed if malnourished) Determine the most appropriate strategy for managing the wound

OptionsResuturing of the wound

This may be an option if the wound edges are healthy and there is enough tissue for sufficient coverage. Deep tension sutures are traditionally used for this purpose.

Application of a wound manager

This is a clear dressing with removable front. Particularly suitable when some granulation tissue is present over the viscera or where there is a high output bowel fistula present in the dehisced wound.

Application of a 'Bogota bag'

This is a clear plastic bag that is cut and sutured to the wound edges and is only a temporary measure to be adopted when the wound cannot be closed and will necessitate a return to theatre for definitive management.

Application of a VAC dressing system

These can be safely used BUT ONLY if the correct layer is interposed between the suction device and the bowel. Failure to adhere to this absolute rule will almost invariably result in the development of multiple bowel fistulae and create an extremely difficult management problem.Theme: Instrument cleaning

A.Immersion in glutaraldehydeB.Gamma irradiationC.AutoclavingD.Ethylene chlorideE.Phenolic lavageF.Disposal of instrument

Please select the most appropriate cleaning method of instrument for the situation described. Each option may be used once, more than once or not at all.

32. A company wishes to sterilise scalpel blades for use.

You answered Autoclaving

The correct answer is Gamma irradiation

Industry often uses gamma irradiation. It is not routinely used in hospitals

33. For sterilisation and cleaning of a colonoscope.

Immersion in glutaraldehyde

Washing systems using glutaraldehyde are often used although development of sensitivity in staff is well known and it is used in closed systems

34. For cleaning instruments following a tonsillectomy in a patient who recieved human growth hormone extract in 1981

You answered Immersion in glutaraldehyde

The correct answer is Disposal of instrument

High risk of prion disease mandates disposal on instruments which is often undertaken following all tonsillectomy procedures regardless of level of percieved risk

Sterilisation

Cleaning refers to removal of physical debris. Disinfection refers to reduction in numbers of viable organisms. Sterilisation is removal of all organisms and spores.

The method chosed depends upon the type of instrument and the procedure for which it will be used.

Sterilisation of surgical instruments typically takes place in an autoclave which uses pressurised steam at a temperature of 134 degrees. This method is reproducible and safe.

However, endoscopy equipment cannot be sterilised by this method as it would damage it. Therefore they are sterilised using 2% glutaraldehyde solution. Since staff may develop hypersensitivity its use is restricted to those pieces of equipment that cannot be sterilised by an alternative means.

In the industrial setting gamma irradiation is used.

Which of the following is not an absorbable suture material?

A.Chromic catgut

B.Nylon

C.Vicryl

D.Dexon

E.Poly diaxone (PDS).

Suture material











Polydiaxonone (PDS)






Braided Synthetic








Synthetic Braided




Time taken to degrade absorbable materials varies Usually by macrophages hydrolysing material

Consider absorbable sutures in situations where long term tissue apposition is not required. In cardiac and vascular surgery non absorbable sutures are usually used.

Suture size



Braided vs monofilamentGenerally speaking braided sutures have better handling characteristics than non braided. However, they are associated with higher bacterial counts. Braided materials are unsuitable for use in vascular surgery as they are potentially thrombogenic.A 43 year old man has symptoms of carcinoid syndrome. Which of the following is the most effective therapeutic agent in controlling the symptoms?

A.Atenolol

B.Octreotide

C.Glucagon

D.Somatostatin

E.Spironolactone

Theme from April 2012 ExamOctreotide is the usual treatment for carcinoid syndrome. Somatostatin inhibits the release of a number of gut hormones. Octreotide is the synthetic alternative to somatostatin and thus the most appropriate therapeutic agent.

Carcinoid syndrome

Carcinoid tumours secrete serotonin Originate in neuroendocrine cells mainly in the intestine (midgut-distal

ileum/appendix) Can occur in the rectum, bronchi Hormonal symptoms mainly occur when disease spreads outside the bowel

Clinical features- Onset: years- Flushing face

- Palpitations- Tricuspid stenosis causing dyspnoea- Asthma- Severe diarrhoea (secretory, persists despite fasting)

Investigation- 5-HIAA in a 24-hour urine collection- Scintigraphy- CT scan

Treatment

Octreotide Surgical removal A 43 year old lady is due to undergo a diagnostic laparoscopy. Which of the

agents listed below should be used for inducing pneumoperitoneum?

A.Argon

B.Helium

C.Air

D.Carbon dioxide

E.Nitrogen

Carbon dioxide is the agent of choice. It is rapidly re-absorbed, does not support combustion and is cheap. It is rapidly cleared from the lungs and so effects on pH are unusual.

Gases for laparoscopic surgery

Laparoscopic surgery may be performed in a number of body cavities. In some areas irrigation solutions are preferred. In the abdomen insufflation with carbon dioxide gas is commonly used. The amount of gas delivered is adjusted to maintain a constant intra-abdominal pressure of between 12 and 15 mmHg. Excessive intra-abdominal pressure may reduce venous return and lead to hypotension. Too little insufflation will risk obscuring the surgical view

A surgeon wishes to determine whether different methods of perioperative shaving have an effect on post operative wound infection rates. Which of the following is the best method for assessing whether one method is better than the other?

A.Cohort study

B.Retrospective study

C.Case controlled study

D.Cross over study

E.Randomised controlled study

A randomised controlled study is the best method for assessing this relationship. It is important to analyse data from RCT's on an intention to treat basis.

Randomised controlled trials

Randomised controlled trials are an established method of comparing two variables. These may consist of comparison of treatments or treatment versus placebo. Ideally the trials should be blinded, usually to the patient and those treating them. In most cases a power calculation should be performed to determine the sample size required to detect a difference.Theme: Electrosurgery

A.Cutting currentB.Coagulation currentC.Blended currentD.FulgurationE.Desiccation

For each of the following electrosurgical applications please select the most likely modality used. Each option may be used once, more than once or not at all.

39. In this modality the active electrode is placed in direct contact with the tissue and is characterised by low current and high voltage over a broad area.

You answered Coagulation current

The correct answer is Desiccation

In desiccation the device is placed in direct contact with the tissues (unlike fulguration). Because it is applied over a broad area it tends not to cause protein damage (unlike coagulation).

40. An electrosurgical mode whereby the electrode is held away from the tissue. The current utilises a low amplitude and high voltage.

Fulguration

Fulguration typically avoids contact between the electrode and the tissue with

the current configured to favor arc formation.

41. A modality in which a sinusoidal, non modulated waveform is produced and vaporises the tissues.

Cutting current

The high energy levels result in tissue vaporisation and cleavage of tissues.

Electrosurgery

Electrosurgery utilises the heat generated by the passage of high frequency alternating electrical current through living tissues. The application of a voltage across human tissue results in the formation of an electrical circuit between the voltage source and the tissue. The tissue acts as a resistor and the level of resistance is determined by the water content of the tissue. It is this resistance that results in the formation of heat.

An alternating current constantly changes the direction in which the current flows, the speed with which this occurs is measured in Hertz. Most diathermy units operate at a frequency of between 200,000 kHZ to 5MHz. This means that tissue such as nerves and muscles will not depolarise (since this seldom occurs at frequencies above 10,000Hz). The current waveform can be adjusted to deliver three main therapeutic modalities; cutting, coagulation and blend.

Types of currentCutting Sinusoidal and non modulated waveform

High average power and current density Precise cutting without thermal damage

Coagulation Modulated current with intermittent dampened sine waves of high peak voltage

Evaporation, rather than vaporisation of intracellular fluid occurs Results in formation of coagulum

Desication Active electrode in direct contact with tissue Low current and high voltage system Results in loss of cellular water but no protein damage

Fulguration Electrode probe is held away from tissue Produces spray effect with local, superficial tissue destruction Low amplitude and high voltage system

Blend Alternating cutting and coagulation modes

Total average power is less than with cutting

Theme: Suture materials

A.Silk 3/0B.Polyglactin 3/0C.Polydioxanone 1/0D.Stainless steel skin clipsE.Stainless steel wire 1/0F.6/0 PolypropyleneG.3/0 Undyed polyglactinH.3/0 Polypropylene

Please select the most appropriate suture for the situation described. Each option may be used once, more than once or not at all.

42. Anchoring a RediVac drain to the skin following a mastectomy.

Silk 3/0

Silk is traditionally used for this purpose because of its reliable knotting.

43. A surgeon wishes to closure the linea alba of the abdominal wall following a laparotomy

Polydioxanone 1/0

A large suture such as 1/0 PDS or 1/0 polypropylene is the standard material for this indication. From the list 1/0 PDS is the most appropriate.

44. Anastomosis of Dacron graft to proximal abdominal aorta during abdominal aortic aneurysm repair.

3/0 Polypropylene

3/0 polypropylene is the suture of choice in this setting. 6/0 is too fine and will not withstand the tensile forces.

Suture material

Suture materialsAgentClassificationDurabilityUsesSpecial points

SilkBraided Biological

Theoretically permanent although strength not preserved









Polydiaxonone (PDS)






Braided Synthetic








Synthetic Braided






Suture size



Braided vs monofilamentGenerally speaking braided sutures have better handling characteristics than non braided. However, they are associated with higher bacterial counts. Braided materials are unsuitable for use in vascular surgery as they are potentially thrombogenic.What is the mechanism of action of ciprofloxacin?

A.Inhibition of DNA gyrase

B.Direct injury to the bacterial cell wall

C.Osmotic damage to the cell

D.Inhibition of reverse transcriptase

E.Destruction of bacterial aquaporin proteins

Antibiotics: mechanism of action

The lists below summarise the site of action of the commonly used antibiotics

Inhibit cell wall formation

penicillins cephalosporins

Inhibit protein synthesis

aminoglycosides (cause misreading of mRNA) chloramphenicol macrolides (e.g. erythromycin) tetracyclines fusidic acid

Inhibit DNA synthesis

quinolones (e.g. ciprofloxacin) metronidazole sulphonamides

trimethoprim

Inhibit RNA synthesis

rifampicin A 73 year old lady with gallstones is about the undergo a laparoscopic

cholecystectomy. The surgeon inserts a Verress needle and performs a successful drop test prior to establishing a pneumoperitoneum. A 5 minute delay ensues before a 10mm infraumbilical trocar is inserted. The surgeon performs a diagnostic laparoscopy which shows a thickened gallbladder but is otherwise normal. The anaesthetist complains that the patient has become hypotensive with a blood pressure of 80/40 mmHg. Of the options below, which is the most appropriate course of action?

A.Release of pneumoperitoneum

B.Perform a laparotomy

C.Administration of intravenous adrenaline

D.Administration of intravenous amiodarone

E.End the operation

Excessive intra-abdominal pressure may cause decreased venous return and hypotension. Since the preliminary laparoscopy did not show any major vascular catastrophe an emergency laparotomy would not be indicated. In most cases the release of pressure is often sufficient. In cases of a vaso-vagal episode (which may be induced by peritoneal stretching) a dose of atropine may be required.

Pneumoperitoneum- therapeutic

During a laparoscopic procedure a surgeon will need to create a pneumoperitoneum. This can be achieved by use of a Verress needle (risk of visceral injury). An alternative is the open "Hassan" style technique. Once access to the abdominal cavity is secured carbon dioxide gas is insufflated to induce a working space. Higher intra-abdominal pressures may compromise venous return and reduce cardiac output. If the blood pressure is seen to drop in this way then release of air, will often improve matters. Should this not be the case then a laparotomy may be necessary to exclude a more significant internal injury.

Which of the following is least likely to reduce the risk of post operative wound infection?

A.Electrical clippers to remove body hair

B.Use of poviodone impregnated drapes

C.Antibiotic prophylaxis for prosthesis placement

D.Routine use of mechanical bowel preparation

E.Chlorhexidine to prepare the skin

The routine use of mechanical bowel preparation is not recommended. There is some recent evidence to support the use of selective gut decontamination. However, this is not in mainstream practice at present.

Surgical site infection

Surgical site infections may occur following a breach in tissue surfaces and allow normal commensals and other pathogens to initiate infection. They are a major cause of morbidity and mortality.

Surgical site infections (SSI) comprise up to 20% of all healthcare associated infections and at least 5% of patients undergoing surgery will develop an SSI as a result.

In many cases the organisms are derived from the patient's own body. Measures that may increase the risk of SSI include:

Shaving the wound using a razor (disposable clipper preferred) Using a non iodine impregnated incise drape if one is deemed to be necessary Tissue hypoxia Delayed administration of prophylactic antibiotics in tourniquet surgery

Preoperatively

Don't remove body hair routinely If hair needs removal, use electrical clippers with single use head (razors

increase infection risk) Antibiotic prophylaxis if:

- placement of prosthesis or valve- clean-contaminated surgery- contaminated surgery

Use local formulary Aim to give single dose IV antibiotic on anaesthesia If a tourniquet is to be used, give prophylactic antibiotics earlier

Intraoperatively

Prepare the skin with alcoholic chlorhexidine (Lowest incidence of SSI) Cover surgical site with dressing

A recent meta analysis has confirmed that administration of supplementary oxygen does not reduce the risk of wound infection. In contrast to previous individual RCT's(1)

Post operativelyTissue viability advice for management of surgical wounds healing by secondary intention

Use of diathermy for skin incisionsIn the NICE guidelines the use of diathermy for skin incisions is not advocated(2). Several randomised controlled trials have been undertaken and demonstrated no increase in risk of SSI when diathermy is used(3).

References1. Brar M et al. Perioperative supplemental oxygen in colorectal patients: a meta analysis. J Surg Res 2011 (166): 227 -235. 2. http://www.nice.org.uk/CG743. Ahmad N and Ahmed A. Meta-analysis of the effectiveness of surgical scalpel or diathermy in making abdominal skin incisions. Ann Surg 2011, 253(1):8-13.A 67 year old women is undergoing a femoral hernia repair and the surgeon is using a bipolar diathermy unit for haemostasis. Which of the following is a recognised risk with the use of bipolar diathermy?

A.Patient burns at the site of the contact plate

B.Fires when used near alcoholic skin preparations that have pooled

C.Coupling injuries

D.Risk of thermal injury to regional vessels as a result of tissue heating

E.Capacitance injuries

In bipolar units the flow of electricity is from one electrode to the other over a small area. As a result a contact plate is not used and coupling and capacitance injuries are uncommon. They have a low risk of thermal injury to adjacent structures and are preferred for this reason. However, they may cause sparks and ignite inflammable solutions.

Diathermy











A 34 year old lady is due to undergo a laparoscopic cholecystectomy. Which of the following intrabdominal pressures should typically be set on the gas insufflation system?

A.4mm Hg

B.10mm Hg

C.20mm Hg

D.40mm Hg

E.60mm Hg

Pressures lower than 7mm Hg are not usually compatible with satisfactory views. Pressures >15mm Hg are usually associated with decreased venous return and hypotension.

Gases for laparoscopic surgery

Laparoscopic surgery may be performed in a number of body cavities. In some areas irrigation solutions are preferred. In the abdomen insufflation with carbon dioxide gas is commonly used. The amount of gas delivered is adjusted to maintain a constant intra-abdominal pressure of between 12 and 15 mmHg. Excessive intra-abdominal pressure may reduce venous return and lead to hypotension. Too little insufflation will risk obscuring the surgical view.

A 53 year old man undergoes an elective right hemicolectomy. A stapled ileo-colic anastomosis is constructed. Eight hours later he becomes tachycardic and passes approximately 600ml of dark red blood per rectum. Which of the following processes is the most likely explanation for this occurrence?

A.Anastomotic leak

B.Discharging mesenteric haematoma

C.Bleeding peptic ulcer

D.Anastomotic staple line bleeding

E.Mesenteric infarct

Safe visceral anastamosis requires:

Mucosal to mucosal apposition

Adequate vascularity Minimal tension

Stapled anastomoses are associated with staple line bleeding and this may typically occur in the early post operative phase. They should be managed conservatively as most will settle.Stapled anastomoses are quicker to perform. Ironically, although they may appear easy they can carry considerably more potential pitfalls than their hand sewn equivalent and should be used with caution by the inexperienced, this is especially true if the bowel is very thick walled.

Anastomoses

A wide variety of anastomoses are constructed in surgical practice. Essentially the term refers to the restoration of luminal continuity. As such they are a feature of both abdominal and vascular surgery.

Visceral anastomoses

For an anastomosis to heal three criteria need to be fulfilled:

Adequate blood supply Mucosal apposition Minimal tension

When these are compromise the anastomosis may dehisce (leak). Even in the best surgical hands some anastomoses are more prone to dehiscence than others. Oesophageal and rectal anastomoses are more prone to leakage and reported leak rates following oesophageal and rectal surgery can be as high as 20%. This figure includes radiological leaks and those with a clinically significant leak will be of a lower order of magnitude. As a rule small bowel anastomoses heal most reliably.

The decision as to how best to achieve mucosal apposition is one for each surgeon. Some will prefer the use of stapling devices as they are quicker to use, others will prefer to perform a sutured anastomosis. The attention to surgical technique is more important than the method chosen and a poorly constructed stapled anastomosis in thickened tissue is far more prone to leakage than a hand sewn anastomosis in the same circumstances.

If an anastomosis looks unsafe then it may be best not to construct one at all. In colonic surgery this is relatively clear cut and most surgeons would bring out an end colostomy. In situations such as oesophageal surgery this is far more problematic and colonic interposition may be required in this situation.

Vascular anastomoses

Most arterial surgery involving bypasses or aneurysm repairs will require construction of an arterial anastomosis. Technique is important and for small diameter distal arterial surgery the intimal hyperplasia resulting from a badly constructed anastomosis may render the whole operation futile before the patient leaves hospital.

Some key points about vascular anastomoses:

Always use non absorbable monofilament suture (e.g. Polypropylene). Round bodied needle. Correct size for anastamosis ( i.e. 6/0 prolene for bottom end of a femoro-

distal bypass). Suture should be continuous and from inside to outside of artery to avoid

raising an intimal flap.

surgical technique

Documents

polypropylene polypropylene

suture of choice

closure devicesa

appropriate suture material

stainless steel wire

ideal suture material

use of suture materials

levels of evidence