fsg 1100-01 spinal pain in aircrew

NOT CONTROLLED WHEN PRINTED

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FSG 1100-01

SPINAL PAIN IN AIRCREW

Document Status: Current Document Type: Flight Surgeon Guideline FSG Number: FSG 1100-01 Original Source: n/a Approval: Aerospace Medical Authority SME: CFEME/Medical Consult Services OPI: Co-Chair, AUMB Effective Date: 06 Dec 2012 Last Reviewed: 06 Dec 2012 REFERENCES:

A. AMA Directive 100-01 Medical Standards for CF Aircrew B. FSG 1900-01 Medications and Aircrew C. FSG 100-02 Aircrew Medicals

RECORD OF AMENDMENTS:

Date

(DD/MMM/YY) Reason for Change OPI/SME

Fully Reviewed

(Y/N)


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TABLE OF CONTENTS:

RECORD OF AMENDMENTS: 1

BACKGROUND 4

DEFINITION 4

PREVALENCE 4

NATURAL HISTORY 4

ETIOLOGY 4

RISK FACTORS 5

CLINICAL HISTORY 6

DIAGNOSTIC IMAGING 7

PHARMACOTHERAPY 8

ANALGESIA 8

ANTI-INFLAMMATORY AGENTS (EG, NSAIDS & COX-2 INHIBITORS) 8

OTHER PAIN-CONTROL ADJUNCTS 8

INJECTION 8

PHYSICAL MODALITIES 8

PHYSIOTHERAPY 9

CHIROPRACTIC 9

MASSAGE THERAPY 9

PHYSICAL CONDITIONING 9

OTHER THERAPEUTIC AND PREVENTIVE CONSIDERATIONS 9

SPECIALIST REFERRAL 10


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LOCAL PHYSIATRIST OR REHAB/SPORTS MEDICINE SPECIALIST 10

CF PHYSIATRIST 10

ORTHOPEDIC SPINAL SURGEON OR SPINAL NEUROSURGEON 10

1 CDN AIR DIV SURG 10

AUMB CONSULTANTS 11

SPECIFIC DIAGNOSES WITH AEROMEDICAL IMPLICATIONS 11

FACET SYNDROME 11

SCOLIOSIS 11

SPONDYLOLISTHESIS/LYSIS 11

SPINAL STENOSIS 11

ACUTE DISC HERNIATION 11

AEROMEDICAL IMPLICATIONS 12

DISPOSITION 12

EMPLOYMENT LIMITATIONS 12

TEMPORARY CATEGORY 13

PERMANENT CATEGORY 13

BIBLIOGRAPHY 13

ANNEX A: PREVENTION STRATEGIES & COUNTERMEASURES A-1

REFERENCES: A-1

ANNEX B – REVIEW OF PHYSICAL MODALITIES FOR SPINAL PAIN B-1

INTRODUCTION TO MODALITIES B-1

CAUTION ABOUT THE USE OF PHYSICAL MODALITIES B-1

CERVICAL MOBILIZATION/SPINAL MANIPULATION: B-1

Guidelines: ................................................................................. B-1


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Substantiation: ........................................................................... B-2

MASSAGE THERAPY: B-3

Guidelines: ................................................................................. B-3

Substantiation ............................................................................ B-3

PHYSICAL CONDITIONING AND EXERCISES: B-4

Guidelines: ................................................................................. B-4

Substantiation ............................................................................ B-4

TRACTION: B-4

Guidelines: ................................................................................. B-4

REFERENCES B-4

ANNEX C – EXERCISE PROTOCOL UNDERGOING EVALUATION AS A COUNTERMEASURE FOR NECK PAIN IN AIRCREW: JOINT CF/USN STUDY C-1

REFERENCES C-1

ANNEX D – DIAGNOSTIC CODES IN CFHIS: GUIDANCE FOR PRACTITIONERS D-1

REFERENCES D-1

ANNEX E – MISCELLANEOUS PEARLS REGARDING ASP & ITS MANAGEMENT E-1

COUNTERWEIGHTS FOR NVGS IN C130J AIRCREW E-1

FUNDAMENTAL CHALLENGES OF THE ASP PROBLEM E-1


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BACKGROUND

1. The aim of this Guideline is to provide aerospace medical practitioners with an approach to the clinical assessment and aeromedical management of spinal pain in aircrew. A certain threshold of severity may compel a member to seek medical attention, but it is also recognized that many may not report their symptoms for fear of an operational flying restriction, so the clinician should specifically ask about it.

2. Neck and back pain are often discussed separately, and there are distinct practice guidelines for the prevention and treatment of each. However, there are sufficiently common features that they are considered together in this guideline.

DEFINITIONS

3. Neck and back pain are symptoms, not specific diseases. Neck pain is considered acute when complaints have been present for < 3 months, sub-acute when present for 3-6 months, and chronic when complaints have been present for > 6 months (Borghouts et al, 1998). Low back pain is often described similarly to neck pain, but chronic back pain is sometimes defined as pain persisting for at least 3 months without response to conservative management. As well, this classification should also be considered when there have been 3 distinct episodes of at least 6 weeks duration within 1 year despite conservative management (ASAMS, 2008). For purposes of this guideline, spinal pain is understood to mean any presentation of neck, or upper or lower back discomfort irrespective of pathophysiology that is of sufficient severity or duration to warrant consideration of an operational flying restriction.

PREVALENCE

4. The lifetime prevalence of neck pain in the general population is estimated to be 40-70% (Guzman et al, 2008). It is estimated that 75-80% of adults will suffer an episode of low back pain in their lifetime. In pilots, the incidence of backache related to flying has been quoted at approximately 13% (ASAMS, 2008), but much higher figures are reported for neck pain: up to 53% in one recent study of CH-146 helicopter aircrew (Harrison & Neary et al, 2011). Another recent study reports both neck & back pain abound in aircrew; in the range of 47-89% in certain Israeli fighter & helicopter pilots (Grossman et al, 2012). See also Annex B for other prevalence data.

NATURAL HISTORY

5. Of those with chronic neck pain who are treated conservatively, approximately 50% report less pain, and improve by a margin of 50% within a 6 month timeframe. Of patients seen within 3 days of onset of back pain, with conservative management 90% would be expected to recover completely within 2 weeks. Recurrence within 6 months can occur in up to 40% of cases. As the duration of the episode increases, the likelihood of resuming normal daily activities declines (ASAMS, 2008; Borghouts et al, 1998).

ETIOLOGY


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6. Pain per se may or may not be a concern unto itself, and partly depends on whether it is associated with harmful sequelae. Pain can originate from a variety of structures and mechanisms including bones, discs and cartilages (articular, intervertebral, cervico-cranial, and facet), ligaments, muscles (from fatigue, strain, or spasm), or the nerves themselves (neuropathic). Pain can also be inflammatory or centrally mediated (originating from ‘failure to dampen-down’ more localized pain stimuli).

7. Causes of Chronic Low Back Pain are typically classified as:

Mechanical low back pain accounts for the majority of low back pain (Chou & a.Shekelle, 2010). Mechanical causes include lumbar strain/sprain, degenerative processes, herniated disc, spinal stenosis, spondylolisthesis;

Non-mechanical causes include neoplasia, inflammatory causes (eg, b.arthritis), infection;

Referred pain can derive from renal, pelvic, gastrointestinal sources, and c.aortic aneurysms

8. Causes of Chronic Neck Pain are typically classified as:

Musculoskeletal conditions including soft tissue, cervical disc degeneration, a.disc herniation, spinal stenosis, spondylolisthesis;

Neurological conditions; b.

Systemic causes such a rheumatic conditions; and c.

Referred pain from myocardial ischemia, gallbladder disease, hiatus hernia, d.GI ulcer, pancreatitis.

RISK FACTORS

9. Risk factors are typically considered to fall into 3 general categories: physical, psychosocial, and individual factors.

Risk Factors for NECK Pain (Ariens et al, 2009; Childs et al, 2008)

Risk Factors for LOW BACK Pain (Chou & Shekelle, 2010)

• Obesity • Obesity • Duration of sitting • Static work postures • Arm posture • Sustained awkward postures • Sustained or repeated force

application • Workplace design

• Rapid repeated motions • Repetitive heavy lifting • Heavy lifting • Neck flexion • Bending


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• Bending/twisting of the trunk • Twisting • Arm force • Poor physical conditioning • Segmental hand-arm vibration • Vibration exposure • Smoking • Smoking

• Cold exposure • History of whiplash • Fatigue • Psychological, psychosocial

factors

10. Stressors of the aeromedical environment also regarded as risk factors include:

Vibration (eg, rotary-wing ops, but prevalent in other platforms like transport, a.also);

Head-mounted mass (eg, helmets, night-vision goggles, helmet-mounted b.displays);

G-stress (most prominent in fast-jet ops); c.

Suboptimal ergonomics (eg, pilots in rotary wing ops; flight engineers doing d.outboard tail-rotor inspections); and

Hypoxia (unknown role in exacerbating associated inflammatory processes). e.

CLINICAL HISTORY

11. The goal of the clinical history is to distinguish whether the pain is non-specific or whether a specific cause can be identified. The presence of red flags increases the likelihood of a specific cause. In addition to identification of red flags, the clinical history should elicit:

The 10 cardinal features of the pain: onset, course, duration, character, a.severity, site, radiation, and aggravating, relieving, and associated factors. Bear in mind patients tend to use terms like ‘neck pain’ rather loosely, and may really be describing symptoms in the upper back or shoulders. Similarly, patients using the term ‘low back pain’ or ‘hip pain’ may be describing referred symptoms originating from structures other than those in which they seem to feel them;

Radicular features such as pain shooting down a limb, paresthesias, b.weakness, or blunting of tendon reflexes suggesting nerve root involvement, and warranting further investigation;

Localization, particularly with provocative maneuvers (eg, tenderness to c.palpation over muscle bodies often suggests muscular origin of pain);


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Aircrew role and associated aggravating issues in particular, approx number d.of NVG hours (eg, high-time rotary-wing pilot with approx 200hrs NVG flying; Griffon FE recently qualified on NVG in Griffon, etc);

History of spinal injury (eg, hyper-flexion/extension syndrome – whiplash) or e.ejection (often associated with ‘occult’ spinal injury);

Associated symptoms: Cervicogenic headaches can be a significant f.distractor and are commonly associated with upper cervical mechanical dysfunction as well as increased muscle tension; and

Medication/substance use: chronic corticosteroids, substance abuse/IV drug g.use.

12. The red flags of neck and low back pain include:

Red Flags for NECK Pain Childs et al, 2008)

Red Flags for LOW BACK Pain (Last & Hulbert, 2009)

• History of trauma • History of trauma • History of malignancy or

symptoms thereof (unexplained fever, weight loss)

• History of malignancy or symptoms thereof

• Numbness, tingling, loss of sensation, or weakness in the arm or hand

• Saddle anaesthesia

• Atrophy of the hand muscles • Severe or progressive lower extremity neurological deficits

• Bowel or bladder dysfunction

• Incidents of notable dizziness/nausea

• A gradual increase in symptoms including extreme morning stiffness, pain in various joints, rashes, digestive difficulties, urethral discharge, eye irritation, especially before age 40.

• Age > 50 or < 20 years

• History of immune compromise • Pain worse when supine

• Severe/sudden onset headache &/or fever & inability to flex the neck

DIAGNOSTIC IMAGING


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13. Without a history of trauma or red flags, diagnostic imaging is not recommended for the initial management of non-specific back or neck pain. In cases of non-specific pain, imaging with MRI (preferably) or CT, is appropriate if: (1) severe or progressive neurological deficits are present; (2) a serious underlying condition is suspected; or (3) pain with radicular symptoms persists for > 4-6 weeks. Plain film radiography need only be sought after one to two months in patients with non-specific pain without red flags or serious disease.

14. Common findings in asymptomatic individuals that should NOT automatically trigger concern include bulging (81%) and herniated (22-40%) discs.

PHARMACOTHERAPY

15. Medications should be used cautiously in aircrew with spinal pain, not only because of potential side effects, but also because of ‘medication vs. indication’ concerns: the disabilities underlying the symptoms must be duly taken into account. Ref B should be consulted for further guidance.

Analgesia 16. Acetaminophen may normally be used liberally (recalling usual dose for healthy adults can routinely be pushed to 1.0g 4x daily, and that under-dosing is a common reason for disappointing symptom control with this agent). ‘Medication vs. indication’ issues should be addressed as above. Any narcotic agent or agent combined with a narcotic is clearly not compatible with flight duty - but clinical judgment must be used in determining appropriate washout periods (normally at least 5 half-lives before return to flight duty).

Anti-inflammatory Agents (eg, NSAIDs & COX-2 Inhibitors) 17. Recall that although agents such as ibuprofen are widely touted as having therapeutic effects related to modulating inflammatory processes, growing evidence suggests they may just be acting as analgesics. Furthermore, in the context of ligamentous injury, they may actually compromise tissue healing and adaptation (Besemann, 2012). Note however that regardless of the underlying mechanism, it is well established that substantial synergy for pain control may arise from use of these agents together with acetaminophen.

Other pain-control adjuncts 18. Low-dose amitriptyline qhs has occasionally been approved for ongoing flight duty, and while gabapentin (and related agents) are normally disqualifying, they have been used in very low doses (<300mg tid) in some cases. Any such therapy, however, must be reviewed and approved by 1 Cdn Air Div consultants if ongoing flight status is sought.

Injection 19. Simple measures such as occipital nerve blocks or trigger point injections can be safely practiced by most primary care physicians. More complex injections such as epidural steroid injections and facet joint injections need to be carried out in specialized clinics.

PHYSICAL MODALITIES


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20. Specific diagnoses will lend themselves to particular types of treatments. Recommendations for specific modalities - and some of the evidence supporting their use - are reviewed in Annex B. Use of CF Health Services resources should, as always, be considered before civilian referrals are made.

Physiotherapy 21. Various modalities employed by physiotherapists can provide relief. Spinal traction and spinal manipulation/mobilizations, especially when combined with rehabilitation exercise, may be beneficial. CF Health Services resources include qualified military and civilian physiotherapists, and some have manipulation & ‘adjustment’ expertise.

Chiropractic 22. Chiropractors are specialists of manual spinal manipulation and can be referred to when this modality is deemed appropriate (although a recent Cochrane Review found that quality of studies is poor and overall effects are small and not clinically important). Caution should, however, be used in selecting a practitioner, since although chiropractors are regulated by their own college, some do not adhere to evidence-based practice guidelines.

Massage Therapy 23. Although many patients report symptomatic relief with this, the CF Spectrum of Care Committee has determined such treatments show no consistent benefit, so this is not covered for CF members.

Physical Conditioning 24. Some evidence supports the use of particular exercises in treating neck and low back pain. Of course, the general health benefits of a balanced exercise program are well-established. Additionally, a specific neck muscle strengthening program designed to alleviate aircrew-related neck pain is currently under investigation, and may be considered for use in selected CF aircrew as an interim measure (see Annex C).

OTHER THERAPEUTIC AND PREVENTIVE CONSIDERATIONS

25. The following entities have no proven benefit for spinal pain but HCPs and patients have anecdotally reported favorable results. With appropriate caution, they may be considered in some cases.

Osteopaths. While osteopathic medicine is a well-recognized and regulated a.discipline abroad (in particular, the USA), some such practitioners operate in Canada without certification or licensure. Further information is available from the Canadian Osteopathic Association website, www.osteopath.ca. On the other hand, it should be recalled that some osteopaths are eligible for licensure as MDs in Canada, and as such may be practicing physicians (see hhttp://www.cpso.on.ca/registering-to-practise-medicine-in-ontario).

Acupuncture. This modality suffers from variable availability and outcome - b.largely because practitioners thereof have variable certification and limited regulation. However, in view of this modality’s dearth of usual adverse effects, trials of its use have a certain appeal for aircrew.


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Meditation / Mindfulness Practices. These have been used as an adjunct in c.a wide variety of chronic pain syndromes with remarkable results (Kabat-Zinn, 1991 is one starting point).

Taoist Tai Chi & Yoga. Some have found these helpful, and they have the d.added advantage of coupling mindfulness techniques with balanced body and limb movements.

Traditional Chinese Medicine, Homeopaths, & Naturopaths. Evidence e.supporting these modalities is poor - and so it is suggested CF HCPs looking after aircrew not advocate them - it should nevertheless be borne in mind that spinal pain patients frustrated with their progress may seek out such resources on their own.

Obus-forme’ and other ‘seat-cosies’ - discouraged for cockpit integration f.reasons.

Mattress/Pillows for sleeping - while no published literature proves the g.veracity of some manufacturers’ claims that a good mattress & pillow are needed for a good night’s sleep, ensuring a spinal pain sufferer sleeps on a decent mattress with a decent pillow just makes good sense.

SPECIALIST REFERRAL

Local Physiatrist or Rehab/Sports Medicine Specialist 26. Referral to these specialists may be considered for patients with more protracted or unusual symptoms not warranting surgical intervention. These consultants vary widely in their availability and accessibility, but in general at the very least can furnish a detailed functional assessment and documentation of a patient’s symptoms.

CF Physiatrist 27. For any CF aircrew member with spinal pain in whom a permanent change of medical category is contemplated, the case should be discussed with the CF Practice Leader in Physiatry (Primary PoC = LCol M. Besemann, [email protected], tel 613-945-6600 x 6515, or through clinic at 613-945-1132 or 1133; Alternate Consultant = Dr Gupta, aval at clinic number), and perhaps referred to him or another suitable CF physiatrist for assessment.

Orthopedic Spinal Surgeon or Spinal Neurosurgeon 28. While it is recognized that these also vary widely in their availability and accessibility, and normally only concern themselves with patients requiring surgical intervention, they can provide useful insight not only into ruling out the necessity of surgery, but also in suggesting conservative management.

1 Cdn Air Div Surg 29. The Div Surg should normally be the first point of contact for disposition of these cases, and may offer suggestions about further management and referral.


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AUMB Consultants 30. For any CF aircrew cases that raise difficult management and/or disposition issues, AUMB consultants are always available to take calls and/or e-mails from managing HCPs. If warranted, CFEME consultants may request that the patient be referred for an evaluation at CFEME Toronto.

SPECIFIC DIAGNOSES WITH AEROMEDICAL IMPLICATIONS

Facet Syndrome 31. Key features of this condition include localized tenderness over the affected joints and muscles, pain with rotation and/or extension, (sclerotomal) pain radiating into limb(s), and the absence of neurological findings. The most effective treatments available include intra-articular facet injections and joint manipulation/mobilization in conjunction with therapeutic exercise. Facet injections require significant expertise to perform and are not readily available at all locations. Patients requiring this treatment should be referred to a physical medicine specialist or anesthesiologist trained in interventional pain management techniques.

Scoliosis 32. While it is well-established that mild degrees of scoliosis are exceedingly common and are not thought to cause symptoms per se, it should be recalled that scoliosis is disqualifying for pilot selection and for those flying ejection-seat-equipped aircraft if any curve is measured to be >20 degrees (Ref A).

Spondylolisthesis/lysis 33. Because of concerns over stability in the event of ejection, these are disqualifying for pilot selection and for those flying ejection-seat-equipped aircraft (Ref A).

Spinal Stenosis 34. Cervical spinal stenosis can be a significant cause of neck pain with or without neurological deficit. ‘Red Flags’ of cervical myelopathy, i.e. atrophy of the hand muscles, etc, should be referred for urgent workup and possible surgical intervention. Lumbar spinal stenosis symptoms (including leg pain and paresthesia with or without low back) are usually exacerbated by spinal extension and prolonged walking and relieved in a flexed-spine position. Cauda-equina syndrome (progressive neurological deficits, urinary incontinence or retention, saddle anesthesia, fecal incontinence, bilateral extremity weakness/numbness) can be an extreme manifestation of lumbar spinal stenosis and is considered a medical emergency.

Acute Disc Herniation 35. Disc herniation in the lumbar and cervical spines is common and usually treated conservatively unless a progressive neurologic deficit ensues. Traction and other physical therapies can be beneficial in uncomplicated disc herniation (see Annex B). Adequate pain management is critical in the early stages to avoid secondary complications. Lumbar epidural steroid injections can be of significant help in relieving acute radicular symptoms as can a short course of oral steroids over 10-14 days without taper.


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AEROMEDICAL IMPLICATIONS

36. If symptoms become incapacitating there are several possible outcomes of aeromedical concern including risks to: (1) mission completion (either current or successive); (2) individual welfare; and/or, (3) loss of trained resources through attrition.

37. Performance decrements may arise from: (1) distraction associated with pain; (2) functional deficits; and/or, (3) the effects of the medications commonly used to treat the condition.

38. Pain may be considered from the standpoint of its particular sequelae which include (in roughly ascending order of severity): worry, distraction, functional impairment, operational flight availability (ranging from time off for medical assessment / intervention to short-term-grounding to temporary and permanent categories), and long-term disability (sometimes with compensation implications).

39. As severity progresses, pain may impact not only upon flying, but also activities of daily living - and these may synergize (e.g., sleep loss can result in performance decrement during flight duty).

DISPOSITION

Employment Limitations 40. Some general considerations for these include:

“Unfit NVG Ops” must be regarded as a severe limitation generally not a.consistent with employability as aircrew, because NVGs are either in use or under implementation for almost all CF aircraft fleets. Aircrew truly requiring this MEL permanently will be assigned A3, but this disposition may have implications for their ongoing employability as aircrew.

“A3 - Unfit Helmet-Mounted Devices (HMD)” is a more accurate description of b.what may truly need to be accomplished (since helmets and other head-mounted devices such as visual cueing systems can be just as disabling for spinal pain sufferers), so is the preferred MEL terminology for most cases. However it should be borne in mind that for the long-term, this disposition is at least as restrictive as 40.a., above.

“A3 - Unfit Rotary Wing Ops” may not be a solution for neck pain suffers c.because of the omnipresence of NVG usage in other platforms noted above. However, this MEL has been applied for various other reasons, typically lumbar spine pain (especially with sciatica) made worse by vibration or, on occasion, lack of mobility to reach switches, etc.

“A7” is reserved for those rare instances where members cannot tolerate d.even wearing a helmet.


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Temporary Category 41. Use of temporary removal from the offending environment (eg, NVG ops or RW duty) may enable ‘tincture of time’ to help heal some underlying processes. Indeed, the operational community has sometimes supported extended use of this (T12 or even T24) for such MELs as ‘Fit Ground Tour Only’. As with any TCat longer than 90 days, such extended restrictions require approval IAW staffing outlined in Ref C.

Permanent Category 42. Once treatment and rehabilitation are completed, long-term disposition considerations include:

Range of motion limitations; a.

Strength deficits; and b.

Functional impairment. c.

43. Regrettably, permanent removal from the environment is the only solution for some aircrew. On the other hand, very occasionally, aircrew with spinal pain have successfully returned to flight duty after prolonged PCats. Consequently, it must be recalled that AUMB will always re-examine cases in light of new information (even simply the passage of significant time, ie, a couple of years or more). Indeed although regarded as ‘permanent’ for administrative purposes, it should also be recalled that PCats can change as noted above.

BIBLIOGRAPHY

1. ASAMS (American Society of Aerospace Medicine Specialists). Clinical practice guideline for chronic low back pain, 2008. http://www.asams.org/guidelines/Completed/NEW%20Back%20Pain_update.htm

2. Ariens, GAM; van Mechalen, W; Bongers, PM; Bouter, LM; van der Wal, G. Physical risk factors for neck pain. Scand J Work Environ Health 2000: 26(1): 7-19.

3. Besemann, M (Practice Leader CF Rehabilitation Medicine) - Personal Communication, DWAN 3 Jul 2012

4. Borghouts, JAJ; Koes, BW; Bouter, LM. The clinical course and prognostic factors for non-specific neck pain: a systematic review. Pain 1998: 77: 1-13.

5. Childs, JD; Cleland, JA, Elliot JM: Teyhen, DS; Wainner RS; Whitman, JM; Sopkey, BJ; Godges, JJ; Flynn, TW; American Physical Therapy Association. Neck pain: clinical practice guideline linked to the International Classification of Functioning, Disability, and Health from the Orthopaedic Section of the American Physical Therapy Association. Orthop Sports Phys Ther 2008; 38(9): A1-34.

6. Chou, R; Qaseem, A; Snow, V; Casey, D; Cross, T; Shekelle, P; Owens, DK. Diagnosis and treatment of low back pain: A joint clinical practice guideline from the


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American College of Physicians and the American Pain Society. Annals of Internal Medicine 2007; 147: 478-491.

7. Chou, R; Shekelle, P. Will this patient develop persistent disabling low back pain? JAMA 2010; 303(13): 1295-1302.

8. Grossman A, Nakdimon I, Chapnik L, Levy Y. Back symptoms in aviators flying different aircraft. Aviat Space Environ Med 2012; 83:702-5.

9. Guzman, J; Haldeman, S; Carroll, LJ; Carragee, EJ; Jurwitz, EL; Peloso, P; Nordin, M; Cassidy, JD; Holm, LW; Cote, P; van der Velde, G; Hogg-Johnson, S. Clinical practice implications of the Bone and Joint Decade 200-2012 Task Force on neck pain and its associated disorders. Spine 2008; 33(45): S199-S213.

10. Harrison MF, Neary JP, Albert WJ, Croll JC. Neck pain and muscular function in a population of CH-146 helicopter aircrew. Aviat Space Environ Med 2011; 82:1125-30

11. Kabat-Zinn J. Full catastrophe living: using the wisdom of your body and mind to face stress, pain, and illness. Delta Trade Paperbacks, 1991. ISBN 0385303122

12. Last, AR; Hulbert, K. Chronic Low Back Pain: Evaluation and Management. American Family Physician. 2009; 79(12):1067-1074.

13. MDGuidelines: Low Back Pain. www.mdguidelines.com/low-back-pain.

14. MDGuidelines: Neck Pain. www.mdguidelines.com/neck-pain.

15. Walker BF, French SD, Grant W, Green S. A Cochrane review of combined chiropractic interventions for low-back pain. Spine 2011; 36(3):230-242

ANNEX A

A-1/2

ANNEX A: PREVENTION STRATEGIES & COUNTERMEASURES

REFERENCES: A. Fraser WD, Crowley JS, Shender BS, Lee VM. Multinational survey of neck pain in rotary wing aircrew (TTCP HUM - in review for approval as open literature publication) B. “Exercise Countermeasures for Aircrew Neck Pain”; DRDC Protocol XX-2012 (in review; see also Annex C) C. Popplow JR, Bossi LLM: Canadian Forces flight trial of individually moulded fibreglass lumbar supports. DCIEM Report 88-RR-12, 1988 D. Proceedings of TTCP HUM TP7 Workshop 29-30 Aug 2011: Identification of research gaps addressing aircrew neck injury issues. E. Fraser, WD. The biomechanical and biochemical response to head-mounted systems. Aerosp Environ Med 2012 (in review) F. Aircrew Neck Strain Way-ahead Workshop, DRDC Toronto, 30 Aug 12

1. Interventions for any issue arising from human-machine interaction may generically be regarded as falling into three categories:

‘Engineering’ solutions remove the problem in the first place (eg, building a.lighter helmets or redesigning cockpit ergonomics);

‘Procedural/Administrative’ solutions employ regulation to ameliorate the b.problem (eg, Procedural Interventions, below); and

‘Protective’ strategies use equipment or other interventions to protect the c.human from the machine & its environment.

2. Re-engineering of CF cockpits & their ergonomics is not felt practicable, and although reducing weight of helmets & NVGs/other head-mounted systems is conceptually appealing, manufacturing limitations currently make these options not yet feasible or at least prohibitively expensive. Accordingly, prevention strategies and countermeasures for spinal pain currently under investigation fall mostly into the latter two categories. Some highlights follow.

3. Procedural Interventions involve limiting exposure to the stress of NVGs and other head-mounted mass. For example, removing NVGs/counterweights when not in use rather than wearing for an entire mission if/when it is practical to do so. Note, however, that this practice can detract from NVG performance due to small unintended adjustments that are associated with additional handling and can lead to the need to re-focus NVGs in-flight. It is important to remember that pre-flight use of an eye lane or other suitable eye chart is the only sure method of optimizing NVG performance.

4. Physical Conditioning interventions have immense face validity: better trained (or at least more favourably balanced) muscles may be stronger and less prone to fatigue, and thus less apt to produce pain from injury or wear. One particularly promising regime is noted at Ref A to Annex C, and is currently under investigation by a US Navy protocol under the auspices of TTCP, with the collaboration of Canada (Ref B, above). However,

ANNEX A

A-2/2

one proviso makes caution with exercise interventions advisable: strengthening muscle may make it less prone to fatigue-related pain, but it may actually increase force on the other elements of the spine (eg, cartilage), and perhaps accelerate damage therein.

5. Supports and Braces. These include the ‘Braced Collar Concept’, which can quickly and easily be swung into/out of place as needed, and is designed to offset compressive forces of the cervical spine. While obvious operational constraints apply, the plan is to develop a prototype that can be shown to alleviate neck pain, and then work on adapting it to the aircrew environment. Custom lumbar supports for low-back pain sufferers have been evaluated (Ref C) and found helpful only if custom-made: ‘one-size-fits-all’ items like Obus-formes are not approved owing to integration concerns. Other measures that have been considered and not felt to be feasible include minimizing NVG weight (conceptually sound but unclear weight reduction targets and prohibitively expensive for the time-being) and ergonomic redesign of cockpit (again conceptually appealing but prohibitive in terms of cost).

6. All of the foregoing efforts are empiric, with limited understanding of the underlying biochemical & biomechanical mechanisms being a given. Accordingly efforts are also being directed at developing models for the study of spinal pain, and at understanding the underlying biomechanisms.

7. Modelling. Ref D summarizes key efforts underway. In essence, finite-element models are being developed and validated to represent the aircrew neck system, with a view to better understanding the forces and mechanics thereof, and to assess the effectiveness of various interventions under various conditions (eg helmet weight reduction, adding NVGs, counterweights, etc). Modelling the aircrew neck is a daunting task given the great number of different structures involved (eg, vertebrae, discs, muscles, ligaments), not to mention individual variations due to gender, size, weight, anatomical variants, etc. Validating the models against valid operational data is also a daunting challenge.

8. Biomechanisms. Ref E reviewed current literature invoking cellular mechanisms in cell damage that involve RNA transcription as early as 15 minutes after a critical stress threshold is reached. For chondrocytes, apoptosis and attendant cell death appears to happen at about 1.2MPa. These processes raise the possibility of biomarkers that not only could help clarify mechanisms for spinal pain but also ultimately be used for assessing individuals suffering spinal pain.

9. Vibration Resonance. Also highlighted at Refs D & F was the possibility that unfavourable mechanical resonances may arise in the CH-146 Griffon seat system. NRC personnel are investigating dampening cushions & other countermeasures (Wichramasinghe, et al - personal communication).

ANNEX B

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ANNEX B – REVIEW OF PHYSICAL MODALITIES FOR SPINAL PAIN

Source: Hebert LJ personal communication (19 May 11)

Introduction to Modalities 1. As reported in a detailed report produced for DND by Dr Patrick Neary et al. (2010), there exists a large body of literature examining neck pain disorders in pilots. In fighter pilots, the pain and discomfort in the cervical region seem to result from deviated head postures, unpreparedness for high +Gz manoeuvres, and/or repeated exposure to large +Gz (over +4Gz) forces (Alricsson 2004; Burnett 2004; Green & Brown 2004; Hamalainen 1998; Hamalainen 1999; Jones 2000; Moncada & Erusalimsky 2002; Sovelius 2006). In contrast to acute neck pain reported by fighter pilots, neck pain in rotary winged aircrew (helicopter pilots) is more chronic, and is probably associated to suboptimal postures adopted during flight, use of NVG, vibration, and maintenance of low level contractions for extended periods (Adam 2004; Ang 2005; Harrison 2007; Thuresson 2003). Therefore, compared to fighter pilots, helicopter pilots experience smaller +Gz forces but are exposed to lower and larger vibration frequencies and magnitudes, which have been linked to the premature onset of some spinal abnormalities (Butler 2000).

Caution about the use of Physical Modalities 2. In the literature, conservative interventions such as physical modalities, manual therapy, massage, exercise therapy, and ergonomic interventions have all been suggested to alleviate the pain associated with mechanical neck pain disorders. However, a critical review of the literature WRT the effectiveness of these treatment modalities suggests that several studies contain methodological flaws, and the beneficial effects of these interventions has yet to be shown (Kay 2005; Sarig-Bahat 2003; Smidt 2005). Therefore, the following is based on the best available evidence and the guidelines proposed by different associations.

Cervical mobilization/Spinal Manipulation:

Guidelines: 3. Clinicians should consider utilizing cervical manipulation and mobilization procedures, thrust and non-thrust, to reduce neck pain and headache. Combining cervical manipulation and mobilization with exercise is more effective for reducing neck pain, headache, and disability than manipulation and mobilization alone. (Recommendation based on strong evidence.)

4. For specific MSK disorders, spinal manipulation may be a valuable intervention. This specialized intervention must be performed by a qualified physiotherapist or, when not available, by another health care provider with appropriate training who uses an evidence-based practice, and who is recognized by the health care team as being the best alternative. Although the risk of complications following spinal manipulation is difficult to determine, this risk exists. CF members should be aware choosing manipulation as a treatment option is a choice the clinician makes depending on the presenting risk factors,

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assessment findings, clinician’s judgment, and CF member preference. CF member should be informed of the relative risks versus the potential benefits.

5. Since the optimal dosage (frequency, intensity, duration) and technique selection of spinal manipulation are unknown, MSK intervention using spinal manipulation should rely on the use of valid and reliable outcome measures to identify clinical signs, symptoms, severity of impairments, level of disability, and discharge criteria to determine when spinal manipulation is indicated or not and when it should be ceased.

6. Use of CF Health Services resources should, as always, be considered before civilian referrals are made. These resources include qualified military and civilian physiotherapists, physicians with manipulation expertise, or other health care providers using an evidence-based practice approach.

Substantiation: 7. Manipulation is a skillful, passive movement of a joint beyond its active limit of motion but inside the limit of its anatomical integrity. It is usually a localized thrust of high velocity and low amplitude, the objective of which is to regain motion and restore function. As an area of practice within physiotherapy, manipulation is included as a treatment technique within manual therapy, which is a comprehensive system of assessment and treatment of the neuromusculoskeletal or somatic system.

8. Spinal manipulation in the CF is indicated only with very specific and limited MSK cases. Physiotherapists and other CF health care providers understand that management of MSK conditions, considering the unique military population, should focus on functional capacities, and that clear and quantified discharge criteria must be used to determine when spinal manipulation is indicated or not and when it should be ceased.

9. Spinal manipulation is a passive modality and it should not be the primary treatment tool used with CF members for treating MSK injuries. Regular maintenance therapy is the use of passive therapies, with no regard to clinical signs, symptoms, severity of impairments or level of disability: this is contrary to the CF standards of practice for MSK conditions. Regular maintenance spinal manipulation is not supported by scientific background. The exclusive use of passive modalities such as manipulative adjustments on a regular basis considerably increases the costs associated to the treatment of MSK conditions with a risk of complications and no evidence of benefits (Koes et al. 1991; Hurwitz 2002) or only very short-term benefits (Hurwitz 1996). In several studies including randomized clinical trials, a review was made about spinal manipulation and mobilization for back and neck pain. Manipulation and mobilization alone showed similar effects as placebo wait period, or control group (Gross 2002). It was also concluded that manual therapies should be done with exercise for improving pain (Gross 2002). Another study reviewed 35 randomized clinical trials comparing spinal manipulation with other treatments. The author concluded that results of all trials indicate that manipulation was not consistently better than other therapies and that no long-term effects from manipulation were found (Koes et al., 1991). These later results are also supported by another recent study that compared the relative effectiveness of cervical spine manipulation and

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mobilization for neck pain in which these two interventions yielded to comparable clinical outcomes (Hurwitz 2002).

10. Risk of harm associated with spinal manipulation. These risks and contraindications are detailed in the literature and are taught in the clinical and didactic curricula of credential. When prescribing/using spinal manipulation, it must be kept in mind that this modality can be harmful and the severity of the consequences necessitates attention. Many studies have reported a number of complications directly attributed to spinal manipulative therapy (Lee 1995; Assendelft 1996; Hurwitz 1996;). More specifically as a result of cervical spinal manipulation, vertebrobasilar complications lead in some cases to residual handicap and even death (Assendelft 1996). Neurologic complications (strokes, myelopathies and radiculopathies), as a result of manipulative procedures, were also reported in relatively young patients (Lee 1995).

11. In a recent study performed by Leaver et al. (2010) to determine whether neck manipulation is more effective for neck pain than mobilization, it was concluded that neck manipulation is not appreciably more effective than mobilization. The use of neck manipulation therefore cannot be justified on the basis of superior effectiveness.

Massage Therapy:

Guidelines: 12. There is little evidence to support the use of massage therapy for the treatment of MSK conditions, specifically; those that are most commonly seen in the CF. Clinicians should not consider utilizing massage therapy unless specific conditions justify its use.

Substantiation: 13. Massage and massage therapy are not well understood. There are many definitions out there that have similar terminology, but not one clear-cut definition is available. Massage is a modality that can be used by many professionals, as it is part of a shared scope of practice. This begs the question as to who would be the preferred choice for such massage techniques. The cost of introducing massage therapy as a modality on its own would be substantial, particularly in the absence of the evidence. In addition, the profession of massage therapy does not fit the criteria of the EBP model (Harris xx, CF PT S&G Manual, 2005).

14. While many patients report symptomatic relief, and some extended health care plans cover a limited number of such treatments annually, the CF Spectrum of Care Committee has determined such treatments show no consistent outcome benefit and ought not normally be covered for CF members. The demand to include massage therapy as a therapeutic modality as one of the services authorized by the CF, has existed for some time. The Spectrum of Care (SoC) Review Committee last considered this topic at their meeting in December 2005. The committee agreed that there remained no evidence that it was beneficial to the member and that it should not be included in the SoC.

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Physical Conditioning and Exercises:

Guidelines: 15. Flexibility exercises can be used for patients with neck symptoms. Examination and targeted flexibility exercises for the following muscles are suggested: anterior/medial/posterior scalenes, upper trapezius, levator scapulae, pectoralis minor, and pectoralis major (Recommendation based on weak evidence). Clinicians should consider the use of coordination, strengthening, and endurance exercises to reduce neck pain and headache. (Recommendation based on strong evidence.)

Substantiation: 16. No convincing evidence supports the role of these in preventing or treating aircrew spinal pain, but the general health benefits of a balanced exercise program (incorporating aerobic, strength/core-strength components) are well-established. However, certain promising programs directed at neck muscle strengthening are under investigation (see Annex C), but caution is in order: although such programs may alleviate pain of muscular origin, they may actually prove HARMFUL by increasing strain on the spine and thus potentially accelerating degenerative changes.

17. Also, as noted by Neary et al. (2010), research using self-reported risk factors (questionnaires) showed that prevalence and development of neck pain in helicopter pilots decreased when they engaged in regular aerobic exercise (Wickes & Greeves 2005) and muscle strength training (Ang & Harms-Ringdahl 2006). However, limited prospective research is available in helicopter pilots to confirm that exercise can reduce neck pain and disability related to flight.

Traction:

Guidelines: 18. Clinicians should consider the use of mechanical intermittent cervical traction, combined with other interventions such as manual therapy and strengthening exercises, for reducing pain and disability in patients with neck and neck-related arm pain (Recommendation based on moderate evidence.)

References

A. Neck Pain: Clinical Practice Guidelines Linked to the International Classification of Functioning, Disability, and Health From the Orthopaedic Section of the American Physical Therapy Association J Orthop Sports Phys Ther 2008;38(9):A1-A34.

B. Neary JP, Salmon DM, Harrison MF, Albert WJ. Pain and Disability in Military Helicopter Aircrew: The Efficacy of Exercise Training Programs in Reducing Neck Pain and Fatigue in Canadian Forces Helicopter Aircrew, Final report, August 20, 2010.

C. Adam J. Results of NVG‐induced neck strain questionnaire study in CH‐146 Griffon aircrew.(eds. Canada, D. R. D.) (2004), p. 153. DRDC Toronto TR 2004, Toronto ON.

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D. Ang B, Linder J and Harms‐Ringdahl K. Neck strength and myoelectric fatigue in fighter and helicopter pilots with a history of neck pain. Aviat Space Environ Med (2005); 76: 375‐380.

E. Ang B and Harms‐Ringdahl K. Neck pain and related disability in helicopter pilots: A survey of prevalence and risk factors. Aviat Space Environ Med (2006); 77: 713‐719.

F. Alricsson M, Harms‐Ringdahl K, Larsson B, Linder J and Werner S. Neck muscle strength and endurance in fighter pilots: effects of a supervised training program. Aviat Space Environ Med (2004); 75: 23‐28.

G. Alricsson M, Harms‐Ringdahl K, Schuldt K, Ekholm J and Linder J. Mobility, muscular strength, and endurance in the cervical spine in Swedish Air Force pilots. Aviat Space Environ Med (2001); 4: 336‐342.

H. Assendelft WJ, Bouter LM, Knipschild PG. Complications of spinal manipulation: A comprehensive literature review. The J of Family Practice. 1996;42(5):475-480.

I. Burnett AF, Naumann FL and Burton EJ. Flight‐training effect on the cervical muscle isometric strength of trainee pilots. Aviat Space Environ Med (2004); 75: 611‐615.

J. Green ND and Brown L. Head positioning and neck muscle activation during air combat. Aviat Space Environ Med (2004); 75: 676‐680.

K. Gross AR, Kay T, Hondras M, Goldsmith C, Haines T, Peloso P, Kennedy C, Hoving J. Manual therapy for mechanical neck disorders: a systematic review. Man Ther. 2002 Aug;7(3):131-49.

L. Gross AR, Kay TM, Kennedy C, Gasner D, Hurley L, Yardley K, Hendry L, McLaughlin L. Clinical practice guideline on the use of manipulation or mobilization in the treatment of adults with mechanical neck disorders. Man Ther. 2002 Nov;7(4):193-205.

M. Hamalainen O. Thoracolumbar pain among fighter pilots. Mil Med (1999); 164: 595‐59

N. Hamalainen O, Heinijoki H and Vanharanta H. Neck training and +Gz‐related neck pain: a preliminary study. Mil Med (1998); 163: 707‐708.

O. Harris SR. How should treatments be critiqued for scientific merit? Phys Ther. 1996;76(2):175-181.

P. Harrison MF, Neary JP, Albert WJ, Veillette DW, McKenzie NP and Croll JC. Trapezius muscle metabolism measured with NIRS in helicopter pilots flying a simulator. Aviat Space Environ Med (2007); 78: 110‐116.

Q. Hurwitz EL, Morgenstern H, Harber P, Kominski GF, Yu F, Adams AH. A randomized trial of chiropractic manipulation and mobilization for patients with neck pain:

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clinical outcomes from the UCLA neck-pain study. Am J Public Health. 2002 Oct;92(10):1634-41

R. Hurwitz EL, Aker PD, Adams AH, Meeker WC, Shekelle PG. Manipulation and mobilization of the cervical spine. A systematic review of the literature. Spine. 1996 Aug 1;21(15):1746-59; discussion 1759-60.

S. Jones JA, Hart SF, Baskin DS, Effenhauser R, Johnson SL, Novas MA, Jennings R and Davis J. Human and behavioural factors contributing to spine‐based neurological cockpit injuries in pilots of high‐performance aircraft: recommendations for management and prevention. Mil Med (2000); 165: 6‐12.

T. Kay TM, Gross A, Goldsmith C, Santaguida PL, Hoving J and Bronfort G. Exercises for mechanical neck disorders. Cochrane Database Syst Rev (2005): CD004250.

U. Lee PL, Carlini WG, McCormick GF, Albers GW. Neurologic complications following chiropractic manipulation: a survey of California neurologists. Neurology. 1995;45:1213-15.

V. Moncada S and Erusalimsky JD. Does nitric oxide modulate mitochondrial energy generation and apoptosis? Nat Rev Mol Cell Biol (2002); 3: 214‐220.

W. Sarig‐Bahat H. Evidence for exercise therapy in mechanical neck disorders. Man Ther (2003); 8: 10‐20.

X. Smidt N, de Vet HC, Bouter LM, Dekker J et al. Effectiveness of exercise therapy: a best‐evidence summary of systematic reviews. Aust J Physiother (2005); 51: 71‐85.

Y. Sovelius R, Oksa J, Rintala H, Huhtala H, Ylinen J and Siitonen S. Trampoline exercise vs. strength training to reduce neck strain in fighter pilots. Aviat Space Environ Med (2006); 77: 20‐25.

Z. Thuresson M, Ang B, Linder J and Harms‐Ringdahl K. Neck muscle activity in helicopter pilots: effect of position and helmet‐mounted equipment. Aviat Space Environ Med (2003); 74: 527‐532.

AA. Wickes S and Greeves J. Epidemiology of flight‐related neck pain in Royal Air Force (RAF) aircrew. Aviat Space

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ANNEX C – EXERCISE PROTOCOL UNDERGOING EVALUATION AS A COUNTERMEASURE FOR NECK PAIN IN AIRCREW: JOINT CF/USN STUDY

References

A. Neck Pain: Clinical Practice Guidelines Linked to the International Classification of Functioning, Disability, and Health From the Orthopaedic Section of the American Physical Therapy Association J Orthop Sports Phys Ther 2008;38(9):A1-A34.

B. DWAN e.mail LCol Morissette 7jun011

1. Ref A reports on a small, well-designed study of exercise interventions in Swedish Air Force helicopter pilots.

2. Results were encouraging, so a joint CF/USN study group under the auspices of TTCP has been established to evaluate these interventions in a larger study in North American air forces (as also noted para 4 of Annex A). The lead author of Ref A is collaborating as a consultant. The planned study will include arms that should enable assessment of the interventions’ usefulness not only as treatment for those who already have neck pain, but also as a preventative measure for those who do not yet have it.

3. It was agreed at Ref B that Ref A could furnish useful information to guide clinical interventions for CF Aircrew until the TTCP study noted above is completed.

4. The interventions used at Ref A can be obtained at: http://journals.lww.com/spinejournal/Abstract/2009/07150/Neck_Shoulder_Exercise_for_Neck_Pain_in_Air_Force.21.aspx

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ANNEX D – DIAGNOSTIC CODES IN CFHIS: GUIDANCE FOR PRACTITIONERS

References

A. ICD-10ca (2009 edition): B. CFHIS coding ‘cheat-sheet’

1. Ref A provides literally hundreds of codes that may be applicable to ASP patients in the CF, but Ref B provides a more concise list that should normally be adhered to (unless it is felt doing so would be misleading). This list is excerpted as follows:

MSK – HEAD & NECK MSK – BACK S19.9 Injury to neck M54.5 Back pain M54.2 Cervicalgia (Neck pain) M51.3 Disc Degeneration M50.9 Cervical disc disorder M51.9 Disc disorder M50.3 Degeneration of cervical spine M54.6 Pain in thoracic spine M54.12 Radiculopathy, cervical region M54.14 Radiculopathy, thoracic region M54.16 Radiculopathy, lumbar region S33.6 Sprain and strain of sacroiliac

joint M54.3 Sciatica

2. Note that no particular code captures any indication of pathology relating to the aircrew environment.

3. Providers must therefore use clinical judgment about which particular code(s) pertain to any given ASP patient. It should however be borne in mind that proper coding is needed for proper epidemiological tracking of the spinal pain in aircrew problem: time-consuming as it may sometimes be, accurate primary care coding does matter because it can be used to improve patient care. Some general pearls about how to assign diagnostic code(s) are as follows:

Differentiate between a historic diagnosis by coding the pathology and the a.date in the PMHx field, and coding for what they are presenting for at the visit in the Assessment field;

Patients will often not present with isolated spinal pain. For example, some b.other condition may also apply, such as old whiplash injury or pre-existing DDD. Codes should be applied for both presenting and underlying condition(s);

Not all aircrew with spinal pain qualify as ‘aircrew-related spinal pain’ in the c.sense intended by the present FSurg GL. For example, a pilot who suffers a lumbar burst-fracture from a sport skydiving mishap, and has not (yet) returned to flight duty should be assigned only S32.0 (fracture of lumbar vertebra). However, once he does return to flight duty, and now has pain

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related to NVG use (where he didn’t before), he should have the added code of M54.2 (Cervicalgia).

In some patients, the link between aircrew duty and spinal pain will be d.unclear. For example, a 50yo FE c/o neck pain when sleeping on his side, but also has mild but tolerable pain on prolonged NVG missions. A code such as M54.2 (Cervicalgia) should be used in this case.

4. Situations not felt amenable to the codes at Ref B & above may be coded at the provider’s discretion, as guided by the CFHIS ‘code-search’ function, or by inspection of Ref A.

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ANNEX E – MISCELLANEOUS PEARLS REGARDING ASP & ITS MANAGEMENT

Counterweights for NVGs in C130J Aircrew 1. The full guidance was obtained from Mr. W. Fraser (DRDC Toronto SME in ASP): “…When mission requirements require a lot of head movement, or where the aircrew are forced to assume unusual postures for long periods of time, then a counterweight may be problematic…[but it is recommended that]…aircrew be provided with the option of using a counterweight. However, it should be up to the individual if they want to use it, & aircrew should be encouraged to adjust the mass for optimal comfort…” (RoDs 6 Dec 11 AUMB refer).

2. While this guidance may be helpful for other aircrew, it should not be generalized without careful scrutiny of the particular circumstances of use. It should also be noted that as of writing of this GL, this guidance has not been institutionalized into SOPs, nor has it been subjected to any staffing approval other than that approving its incorporation into this guideline.

Fundamental Challenges of the ASP Problem “Design Flaws in the Human Spine”: it evolved to serve quadruped a.

vertebrates, with its mechanical members operating partly in tension (like a chain). When vertebrates rose to their hind limbs, these members underwent compression instead. Furthermore, in the last century, the average life-expectancy has doubled (from about 40 years to almost 80). So not only is the system being used outside its ‘design envelope’, but also its ‘service life’ has been doubled without the benefit of time for evolutionary adaptation. It should be borne in mind that all this applies to non-aircrew population as well; the stresses of the aerospace environment like +Gz, vibration, head-mounted mass (NVGs, helmets, JHMCS, etc), and unfavorable posture compound the problem. Accordingly, since spinal pain is exceedingly common in the general population (as indicated in para 4. of main body of this FSurg GL), it is no great surprise that ASP is as prevalent as it is.

Endpoints: Pain is the only readily available one for study, and this correlates b.with long-term damage (like DDD) unpredictably. Thus aeromedical concerns are not just limited to pain & disability, but also to unknown long-term issues as well (as also noted paras 36.-39., of main body, above). In other words, while spinal pain, tissue damage, & functional / operational disability surely represent a disease spectrum, their relationship is not at all clear-cut - so using any of them as study endpoints is problematic

fsg 1100-01 spinal pain in aircrew

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