Pain in patients with spinal cord injury

1. Pain in patients with spinal cord injury Naveen Kumar Specialist Registrar in Spinal injuries & Rehabilitation

2. Scope of the problem • 47 – 96 (avg 66) % of SCI individuals experience pain ( Ref 1979-1995- 8 studies) • 50% musculoskeletal • 30% neurogenic • 5 - 45% experience severe disabling pain • 94% chronic pain • Comparative Neglect: Pain 2400 ( 1977-1997), 19 pain in SCI

3. Incidence of pain • More common in patients with: • Injuries due to gunshot wounds and violence • Lower level of injury • Incomplete SCI ? • Spasticity

4. Psychosocial factors • Depression / Sadness • Adjustment disorders • Anger • Anxiety • Stress

5. Patient evaluation • Detailed history • Quality Of Pain • Distribution Of Pain • Relieving Factors • Aggravating Factors • Physical examination • Diagnostic tests

6. Pain syndrome classification • Musculoskeletal • Neuropathic • Visceral

7. Pain classification Neuropathic • Above the level • At the level • Below the level

9. At-level Neuropathic pain segmental end-zone Radicular Mechanisms – nerve root compression/trauma – spinal cord damage – generation of nerve activity

10. Below-level Neuropathic pain • central • dysaesthetic • remote • Phantom

11. Below-level Neuropathic pain Mechanisms • – Spinal cord and brain • – Loss of inhibition • – Sensitization of nerve cells • – reorganisation?

12. Musculoskeletal pain syndrome • Bone, joint, muscle trauma • Tendon inflammation • Muscle spasm • Overuse syndrome • Instability of spine

13. Vertebral column pain • Neck, middle back, low back pain • Spine deformities • Arthritis • X-rays • evaluate instrumentation placement • evaluate degenerative changes

14. Mechanical instability of spine • Most common after cervical spine injury • Due to injury to ligaments, fx of spine • Pain around the spine

15. Treatment for mechanical instability of spine • Relieved by immobilization • Rest, bracing • Medications • NSAIDs • Opiates • Surgical fusion

16. Muscle spasm pain • Pain with visible and palpable spasms • Anti-inflammatory medications • Anti-spasticity medications • Baclofen • Tizanidine

17. Secondary overuse syndromes • More common in paraplegics • Pain in intact areas • Delayed onset • Shoulder pain: arthritis, tendinitis • Pain from CTS, ulnar nerve entrapment • Other arthritis

18. Shoulder pain • 50-95% prevalence • Secondary to: • Weight bearing • Overuse • Muscle imbalance

19. Shoulder pain: Differential diagnoses • Rotator cuff tendinitis and tear • Muscle pain • Radiculopathy • Arthritis

20. Elbow / Hand pain • Elbow pain (32%) • Hand pain (48%) • Differential diagnosis • Epicondylitis / tendinitis • Olecranon bursitis • Arthritis • CTS, Ulnar nerve entrapment

21. Diagnostic tests • Physical examination • Plain x-ray • MRI • EMG

22. Treatment options • Rest • Therapeutic exercises • Modalities- TENS, Acupuncture • Changes in positioning, ergonomics • Changes in equipment • Splints • Weight reduction

23. Treatment options • Anti-inflammatory medication • Opioids • Injections • Acupuncture • Surgical release for CTS

24. Neuropathic pain • Nerve root entrapment • Syringomyelia • Transitional zone pain • Central dysesthesia syndrome • Nerve entrapment syndrome

25. Nerve root pain / radicular • Unilateral pain in the single nerve root distribution • At the level of spinal trauma • Pain since the time of injury • Lancinating, burning, stabbing, shooting, paroxysmal, allodynia, hyperesthesia

26. Transitional zone pain • At the border of normal sensation and numb skin • Bilateral • Burning, aching, allodynia, tingling • Pain within first few months of injury • Injury to the gray matter of dorsal horn

27. Central pain syndrome • Pain below the level of injury • Constant • Fluctuates with mood or activity • Responds poorly to medications or other treatment

28. Pathophysiology of Neuropathic pain • “Imbalance hypothesis” • Imbalance between dorsal column and spinothalamic tracts • “Pattern-generating mechanism” and “loss of spinal inhibitory mechanisms” • Loss of inhibitory control • Focal hyperactivity in the spinal cord and thalamus

29. Pain description • Tingling • Shooting • Stabbing • Squeezing • Pressure • Cold • Numbness • Muscle cramp

30. Exacerbating factors • Noxious stimuli below the level of injury • Fatigue • Lack of distraction • Smoking • Psychological stress • Overexertion • Weather changes

31. Nerve entrapment syndrome • Carpal tunnel syndrome • Ulnar nerve entrapment • at the wrist • across the elbow • Radial nerve entrapment

32. Nerve entrapment syndrome: risk factors • Use of assistive devices • Routine pressure relief • Weight shifts • Transfers • Wheelchair mobility

33. Syringomyelia (Syrinx) • Delayed onset, years • New neurological deficits • Constant, burning pain • Pain to touch • Diagnosed with MRI • Treatment: shunt

34. Syringomyelia (Syrinx) • Delayed onset, years • New neurological deficits • Constant, burning pain • Pain to touch • Diagnosed with MRI • Treatment: shunt

35. Treatment • Pharmacological • Nerve blocks • Physical • Surgical • Stimulation techniques • Psychological • Acupuncture

36. Pharmacological treatment • Anticonvulsants • Antidepressants: • Alpha-adrenergic agonists • Opioids • Anti-spasticity medication

37. Anti-seizure medications • Carbamazepine (Tegretol) • Initially 100 mg, bd, gradually according to response; usual 200 mg tds/qid, up to 1.6 g • Gabapentin (Neurontin) • 300 mg on d1, then 300 mg BD d2, then 300 mg TDS on d3 Increase to response in steps of 300 mg daily (in 3 divided doses) every 2–3 days to max. 3.6 g daily

38. Antidepressants • Tricylic antidepressants: amitriptyline (Elavil), nortriptyline (orth hypo), imi & desipramine • Effective in neuropathic pain • Increase pain inhibitory mechanisms • May be used in combination with anti-seizure medication

39. Anti-spasticity medication • Relief of muscle spasms • Baclofen • Clonazepam • Dantrium

40. Alpha adrenergic agonists • Relief of neuropathic pain • Clonidine: By mouth, 50–100 micrograms 3 times daily, increased every second or third day; usual max. dose 1.2 mg daily • Zanaflex: over 18 years, initially 2 mg daily as a single dose increased according to response at intervals of at least 3–4 days in steps of 2 mg daily (and given in divided doses) usually up to 24 mg daily in 3–4 divided doses; max. 36 mg daily

41. Capsacin • Topical, 0.025%, • Applied to skin overlying the painful area, a small amount 4 times daily • Deplete substance P,cause pain from nerve ending

42. Opioids • May be used in neuropathic pain • Side effects • Physical dependency • Severe constipation • Mild cognitive impairment • Risk for addiction ( 3/52)

43. Therapy • Positioning • Modify transfer techniques • Splinting • Padded gloves / elbow pads • Exercise routines

44. Other interventions • Acupuncture • TENS unit • Spinal cord stimulator • Dorsal rhizotomy

45. TENS unit • Electrical stimulation on skin • More effective at the level of injury? • Requires a therapist for set-up

46. Spinal cord stimulator • Not generally helpful with SCI pain • More effective with transitional zone or radicular pain • Initial improvement in 20-75% of patients • Long term efficacy in 10-40%

47. Surgical intervention • Spine stabilization • Removal of instrumentation • Decompression of impinged nerve roots • Decompression surgery for syrinx

48. Dorsal root rhizotomy • May be more effective in radicular pain or neuropathic pain at the level of injury • Risks of cerebrospinal fluid leaks, sensory or motor level changes

49. Psychological treatment • Psychological assessment • Cognitive behavioral therapy • Relaxation techniques • Biofeedback • Peer support

50. Visceral pain • Above, at or below the level of injury • Poorly localized if at or below the LOI • Non-specific symptoms: • Nausea, vomiting, anorexia • Autonomic dysreflexia • Fever