infections of spine
TRANSCRIPT
POTT’S POTT’S SPINE
VERTEBRAL ANATOMY
Centre portion of each intervertebral disc is filled with gel like elastic substance(NUCLEUS PULPOSUS) which along with sturdy elastic collagen fibres(ANNULUS FIBROSUS)transmits stress from vertebra to vertebra
Annulus fibrosus enhances rotational stability of spine and helps to resist compressive forces
EMBRYOLOGY OF VERTEBRAL COLUMN
Formed from sclerotome portions of somites(derived from paraxial mesoderm)
Each sclerotome-loosely arranged cells cranially & densely packed cells caudally.
Some of the densely packed cells move cranially opposite the centre of myotome
INTERVERTEBRAL DISC
Remainin densely packed cells fuse with loosely arranged cells of immediately caudal sclerotome
MESENCHYMAL CENTRUM(primordium of body of vertebra)
Nerves lie in close relation to IVD and intersegmental arteries lie on each side of vertebral bodies.
Notochord persists and enlarges only in the region of IVD…..contributes to formn of NUCLEUS PULPOSUS which later gets surrounded by circular fibres of ANNULUS FIBROSUS
NP+AF
INTERVERTEBRAL DISC
Resegmentation of sclerotomes into definitive vertebrae causes myotomes to bridge the IVD…gives them the capacity to move the spine
FORMS
Spinous and transverse processes develop from chondrification centres(which appear at 6th week of embryonic life) in vertebral arch.
Ossification in vertebral arches-8th week At birth-each vertebra has 3 bony parts
connected by cartilageBony halves fuse during 1st 3-5yrs
Five secondary ossificn centres appear in vertebrae after pubrty
All secondary centres unite with rest of vertebrae-25yrs
POTT’S POTT’S SPINE
Dr SREEDEVI PK
TUBERCULOSIS OF SPINE
Vertebral TB-M.C form of skeletal TB(50% of all cases of TB of bones&joints)
M.C-1st 3 decades Equal in both sexes Any one/several vertebrae M.C-Lowr thoracic & lumbar spine
Infectious exudate may spread anteriorly beneath anterior longitudinal
ligament~>neighbouring vertebrae
Advances&destroys epiphyseal cortex,intervertebral disc&adj vertebrae
Infection begins in cancellous area of vertebral
body(Central/anterior/epiphyseal in location)
Note:infection of posterior bony arch and tyransverse process is unusual
Granulation tissue develops posteriorly-encircles & compresses spinal cord & nerve roots(more likely in thoracic spine ‘cause of small calibre of spinal canal here)
Posterior element involvt of C2(axial CT image showing reactive sclerosis)
COURSE……
ANTERIORLY……………
Exudate forms&netrates periosteum,accumulating beneath anterior longit.ligament(ALL)
Penetrates the ligament
Abscess
Migrates in various directions.Abscess tracks along lines of least resistance(along fascial planes,blood vessels & nerves
CERVICAL………
Collects behind
prevertebral fascia
Spreads laterally to sterno mastoid(a point at postr
edge))
Protrudes fwd..bulge
into pharynx
May gravitate to
mediastinum
Trachea,esophagus,pleural cavity
THORACIC
Remains locally confined as a bulbous mass for a long time
Back-pressre against spinal
cord
PARAPLEGIA
Exudate may spread laterally to extrapleural space-induces NON SPECIFIC PLEURAL EFFUSION
If exudate penetrates ALL, occupies mediastinum OR gravitates through diaphragm
to the LUMBAR ASPECT Rarely,thoracic cold abscess may track
backward b/w transverse processes&follow intercostal nerve-erupts on chest wall.
LUMBAR…..
A
•Tuberculous exudate enters PSOAS SHEATH
•Appears below inguinal ligament on medial aspect of thigh
B
•May spread laterally beneath iliac fascia
•Emerges at iliac crest at the anterior superior iliac spine
C
•Follows great vessels….may erupt alongside femoral vessels in triangle of Scarpa or in gluteal region
•Or forms an abscess abpve iliac crest posteriorly
REGIONAL DISTRIBUTION….
DORSAL-42% LUMBAR-26% DORSOLUMBAR-12% CERVICAL-12% CERVICODORSAL-5% LUMBOSACRAL-3%
Route of spread TB of spine is always secondary.
Bacteria reach spine via hematogenous route from lungs or lymph nodes.
TYPES OF VERTEBRAL TB
1) PARADISCAL – COMMONEST TYPE. BETWEEN THE TWO CONTIGUOUS AREAS OF TWO ADJACENT VERTEBRAE.
2) CENTRAL- BODY OF SINGLE VERTEBRA IS AFFETED.
3) ANTERIOR- INFECTION IS LOCALISED TO THE ANTERIOR PORTION OF THE VERTEBRAE.
4)POSTERIOR-POSTERIOR COMPLEX i.e PEDICLE,LAMIINA,SPINOUS OR TRANSVERSE PROCESS ARE INVOLVED.
5)APPENDICEAL-RARE, INVOLVES TRANSVERSE PROCESS.
COLD ABSCESS
Collection of pus and tubercular debris from diseased vertebrae.
Can travel in any direction.
Spread beneath the anterior longitudinal ligament- pre vertebral abscess.
Spread posteriorly and cause pressure over the spinal cord.
Spread through the sides of the vertebra –
para vertebral abscess.
Sometimes penetrates the anterior longitudinal ligament – lines of least resistance i.e. fascial planes,vessels,nerves
CLINICAL PICTURE
ACTIVE STAGE Constitutional symptoms antedate local spinal
involvement……anorexia,nausea,weakness,weight loss,night sweats,afternoon or evenin rise of temp
Frequently iniated by an exanthem or trauma. Spine- -Stiff and painful on movt. - Pain is localised to site of
involvement/referred dependin on specific nerve root irritation
- Localised KYPHOTIC deformity. (Tender to percussion)
Vertebral muscle spasm+ Night cries…..movt b/w inflamed surfaces. Cold abscess maybe + Pressure effects-dysphagia(mediastinal) Dyspnoea
Hoarseness(retropharyngeal) Restricted hip
extensn(Psoas abscess)
GIBBUS DEFORMITY IN TB
If any suspicion of TB spine……….. Palpate spinous processes by
sliding finger from cervical spine to sacrum…….so that even a small knuckle kyphosis (step/prominence) is not missed…………..thus making the diagnosis before gross vertebral destruction has occurred.
Stiffness,weakness&awkwardness of lower extremities herald onset of PARAPLEGIA.
CHARACTERISTICS OF SPECIFIC SPINAL INVOLVEMENT
CERVICAL Pain over cervical vertbrae/referred to
occiput/upper extremities Pain aggravated by pressure on top of head Neck rigidity Deformity-normal lordosis is reduced &
head is supported in hands Paralysis of arms before legs Occasionally death due to dislocation
LOW CERVICAL & UPPER THORACIC Pain along brachial plexus or intercostal
nerves Marked rigidity with angular kyphosis Abscess-
retropharyngeal,supraclavicular,mediastinal. Cord symptoms L.C Arms affected first Horners syndrome Neck rigidity-head&neck turn as one
THORACIC&THORACOLUMBAR Pain referred to lower extremities(esp
lateral aspect of thighs) Girdle pain Marked angular kyphosis Iliac or psoas abscess
LUMBOSACRAL Referred pain to lower extremities Deformity slight Psoas abscess Flexion of hips
ABSCESSES & SINUSES….. Cervical&dorsal-Can present away from
vertebral column:- Paraspinal regions,posterior/anterior
cervical triangles,along brachial pkexus in axilla,along intercostal spaces on chest wall.
Dorsolumbar&lumbar-Abscess freq tracks down psoas sheath……palpable in iliac fossa,lumbar triangle,upper part of thigh below inguinal ligmt,knee
Psoas abscess-Pseudo-hip flexion deformity(No limitation of internal & external rotation of hip jt when tested in position of flexion deformity)
- Can present as a lump in iliac foss - HEALED STAGE- -Not ill- -Regains lost weight- -No evening rise of temp- -No spinal pain/tenderness- -ESR falls
-Radiological E/O bone healing in serial Xrays
-But deformity persists
Bony ankylosis of L3-L4 resulting in kyphosis in an old case of TB spondylitis
INVESTIGATIONS………
BLOOD-Hb-anemia TC –lymphocytosis ESR raised S.proteins-Hypoproteinemia Mantoux-helpful in children<2-3yrs….not
diagnostic though
X-RAY APPEARANCES
Depending on site of lesion TB spine………..
1) PARADISCAL-M.C2) CENTRAL3) ANTERIOR4) APPENDICEAL
Earliest radiological finding-narrowing of disc space
Loss of definition of paradiscal margins Bones look rarefied and osteopenic(40% Ca
loss-radiolucent signs) Observed before osseous destructive
changes Trabecular destruction-atleast 3-5 months
from beginning of infectious process
Late changes-Anterior wedge compression in anterior vertebral involvement
Central vertebral body collapse(CONCERTINA COLLAPSE) in central involvement.
Destruction of posterior elements in posterior affection.
Soft tissue swelling&calcificn-highly predictive of TB
Healing stages-vertebral body&posterior elements dense(sclerosis)
Collapsed vertebral body L1-L3
Cervical-b/w vertebral bodies&pharynx(retropharyngeal)-birdnest shadow
Upper thoracic-V-shapd/bulbous/heart shaped shadow&widened mediastinum
Low thoracic&thoracolumbar-fusiform shadow occupy site of psoas shadow. Increased density and lessening of size of shadow indicates calcification and healing
Axial CT-vertebral body destruction,paravertebral abscess ext into spinal canal
MODERN IMAGING TECHNIQUES
CT SCAN• Assessmt of destructive lesions of vertebral
column• Paravertebral soft tissue swellings• Degree of neural compromise• Specially useful in-1) posterior spinal disease2)CraNiovertebral&cervicodorsal TB3)Sacroiliac joint TB• Suspected areas of disease should be localized
before taking CT
ISOTOPE BONE SCAN-Localises diseased area by demonstratin a hot spot even when lesions<5mm
Note:atleaqst 30-40% calcium must be removed from a particlr area for radiolucent changes to become visible
Anterior wedging and erosion of T9
Axial CT image showing vertebral body destruction&adj soft tissue mass
MRI• Diagnosis of TB in rare sites incl
posterior elements,vertebral appendages&sacroiliac jt
• Excellent modality to judge health of spinal cord…detects cord compression.
ULTRASOUND ECHOGRAPHSTo diagnose presence & size of
tuberculous abscess in lumbar vertebral disease.
GALLIUM SCAN-For disseminated TB BIOPSY-By percutaneous technique with
CT guidance………biopsy mateial subjected to culture
BIOPSY & CULTURE-MOST DEFINITIVE DIAGNOSTIC TEST
Radiological & MRI e/o healing lags behind biological healing processes in spinal TB.
X-rays,MRI-Upto 5months of starting multidrugtherapy may actually show deterioration in most pts.
If images don’t show improvement whwn repeated>6 months after onset of Rx….consider alternate diagnosis/therapeutically refractory disease.
Rarely-healing accomp by fat replacemt of healed area
COMPLICATIONS
1) PARAPLEGIA2) COLD ABSCESS3) SINUSES4) SECONDARY INFECTION5) FATALITY
DIFFERENTIAL DIAGNOSIS
Pyogenic infections Typhoid spine Brucella spondylitis Mycotic spondylituis Syphilitic infection Tumorous conditions Primary malignant tumors Multiple myeloma
Lymphomas Secondary neoplastic deposits HistiocytosisX Local developmental abnormalities of
spine Spinal osteochondrosis Traumatic conditions Osteoporotic conditions Spondylolisthesis
MANAGEMENT
AIMS OF Rx Halt progression of destruction and
deformity Prevent and overcome paraplegia.Treatment should be
prolonged ….and a cautious attitude
maintained for many years…as
recrudescence of disease can occur even
years later!!
GENERAL SUPPORTIVE
CHEMOTHERAPY
SURGERY
CHEMOTHERAPY
Isoniazid(INH)-most effective anti-TB drug INH-5mg/kg/day……300mg usually(adults) 10-15mg/kg/day……………...children. S/E-peripheral neuropathy,anemia,hepatitis
Pyridoxine 50mg to be supplemented daily
MONITOR LFT
Ethambutol-25mg/kg/day X 60days 15mg/kg single dose
thereafter.S/E-Visual disturbances……avoid in
childrenPERIODIC
OPHTHALMIC CHECK
UPS
Streptomycin Adults 0.75-1g/day X 60days 1g/day 2-3times weekly thereafter Children 15-25mg/kg/day INTRAMUSCULARS/E-Ototoxicity,nephrotoxicity AVOID IN RENAL
INSUFFICIENCY
RIFAMPICIN Adult-600mg Children-10mg/kg/day Oral single daily dose given ½ hr before
breakfast Relatively mild toxic effects Colors urine&othr body fluids bright
orange
***COMBINATION CHEMOTHERAPY*** Delays emergence of drug resistant
strains of bacilli. Rx regimen- HRE X 6MONTH….If at the end of 6months,clinical &
radiological response satisfactory, IE X 12-18MONTHS
Failure to respond to first line drugs……(due to bacterial resistance/allergic intolerance/toxic effects)…..use SECOND LINE DRUGS
Cycloserine,Ethionamide,Kanamycin,Amikacin,Thiocetazone
Failure to respond despite adq chemotherapy with radiological e/o progression of disease or neurological involvement emerges.
SURGICAL INTERVENTION
SURGICAL TREATMENT
INDICATIONS1) Failure to respond to ATT2) Radiological e/o progression(enlargmt
of paraspinal abscess shadow)3) Imminent vertebral collapse4) Instability of spine5) Progressive neurological deficit
SURGICAL OBJECTIVES1) Excise infected tissue as completely as
possible2) Decompress intraspinal neural
elements3) Reduce spinal deformity4) Provide stability by spinal fusion
PRINCIPLES1) Removal of all diseased tissue by
thorough debridement2) Correction of deformity3) Interbody bone grafting & stabilization.4) Relief of pressure on intraspinal
contents.
WHAT IS DONE??????
Major focus of disease is removed Spinal deformity reduced Intraspinal neural elements
decompressed Bone defect obliterated Spinal stability provided by autogenous
bone grafts
PREOPERATIVELY, an ATT regimen is maintained(atleast 3months)…….
Severe destruction-external skeletal fixation with a HALO-PELVIC DEVICE.
Following removal of diseased focus,distraction aids in overcoming kyphosis.
Later…bone grafting
OPERATIVE AAPROACHES
Lesions of C4-C6-lateral approach or anterior approach
Lesions of C7-T4-posterior thoracoplasty approach by removing third rib on left side
Lesions below T40Spine is approached from left
Aorta –landmark Incision- Along a rib that’s
2ribs higher than the rib that arises at apex of kyphosis.
Surgical procedures
Lateral rhachotomy Costotrasversectomy Albee procedure-aims to unite the
spinous processes by a single cortical graft(s/c aspect of tibia)….fixed by sewing muscles over it.
Hibbs procedure-only local bone is used Combined procedure Circumduction fusion
POTT’S PARAPLEGIA
POTT’S PARAPLEGIA
Pott’s paraplegia can be due to – - inflammatory causes- oedema,abscess - mechanical causes-tubercular debris - intrinsic causes-pathological dislocation - spinal tumour d/s- extradural granuloma Most commonly occurs in TB of dorsal
spine because spinal canal is narrowest in this part
Seddon’s Classification:
GROUP A_-Early onset - This comes up in active stage of the disease within first 2 years.
Compressive Agents are inflammatory edema, granulation, abscess, casseous material, sequestra and rarely ischaemic lesion.
GROUP B -Late onset- Usually after 2 years of onset of the disease. due to recurrence or by mechanical pressure. This can be better
divided into paraplegia with active disease and with healed disease.
Active disease - Caseous material, debris, sequestrated disc or bone, internal gibbus, stenosis and deformity can cause compression.
Healed disease - Usually internal gibbus and acute kyphotic deformity can also give late onset paraplegia. Usually there is a continuous traction, compression leading to paraplegia.
Kumar’s classification oftuberculous paraplegiastage Clinical features
1 Negligible Unaware of neural deficit,Upgoing Plantar / Ankle clonus
2 Mild Walk with support
3 Moderate Nonambulatory,Paralysis in extention,sensory loss <50%
4 Severe 3+ paralysis in flexion/sensory loss>50%/ Sphinters involved
CLINICAL FEATURES OF PARAPLEGIA- - clumsiness - twitching - increased reflexes - clonus - positive Babinski’s sign
In Pott’s paraplegia , motor functions are affected first.
The paralysis follows the following stages-
muscle weakness, spasticity , incoordination, paraplegia in extension , flexor spasms,paraplegia in flexion and flaccid paraplegia lastly.
TREATMENT OF POTT’S PARAPLEGIA 1) ATT 2)SPINE PUT TO ABSOLUTE REST 3)PARALYSED LIMBS SHOULD BE TAKEN
CARE OF. 4)REPEATED NEUROLOGICAL
EXAMINATION TO CHECK FOR WORSENING.
Surgical indications1. No sign of Neurological recovery after trial of
3-4 weeks therapy2. Neurological complication during treatment3. Neuro deficit becoming worse4. Recurrence of neuro complication5. Prevertebral cervical abscesses,neurological
signs& difficulty in deglutition& respiration6. Advanced cases- Sphincter involvement,
flaccid paralysis,Severe flexor spasms
MIDDLE PATH REGIMEN
Widely accepted regimen for tb spine Admission,rest in bed or pop cast. Chemotherapy X-ray and ESR once in 3 months Gradual mobilisation in the absence of
neurological involvement. Spinal braces-18 months to 2 years.
Abscesses are aspirated out drained. Sinuses heal within 6-12 weeks If no neurological complications develop
and patient is responding to the 3-drug therapy , surgery is unnecessary.
Excisional surgery for posterior spinal disease.
Operational debridement for patients who do not show arrest of disease after 3-6 months of chemotheray.