Back Pain & Treatment Modalities

1. Back Pain & Treatment Modalities Dr. Dawood Nasir Director Acute Pain & Regional Anesthesia UTSouthwestern Medical Center

2. Overview • Back pain affects most people at least once over their lifetime. • It can be a cause for lost wages & productivity • Most people will become better in 6 weeks

3. Anatomy • The back is composed of vertebrae, muscles, ligaments, intervertebral disc,& nerves. • There are 7 cervical, 12 thoracic, 5 lumbar & 5 coccygeal vertebrae • Spinal cord has cervical lordosis, Thoracic kyphosis, & lumbar lordosis

4. Assessment of Low Back Pain • History & Physical: Nocturnal exacerbation occurs w tumors or inf, w benign causes like herniated disc pain improves w bed rest • Limitation of spinal motion correlates with the presence of lower back disability • Palpation: Gentle & systemic palpation of the back, coccyx, sacrum, levator ani, coccygeus, & piriformis ms, & associated ligament done • Muscle spasm: has localized tenderness, & increase in ms tone

5. Assessment of Back Pain • Pain on percussion occurs with metastases or inf, does not occur w disc protrusion & spasm • Radiological test: Plain Xrays show degenrative disc ds, spondylitis, compression fx, metabolic bone disorder, bone tumors, congenital anomalies & transitional vertebrae • Oblique view of lumbosacral level is used to visualize facet & sacroiliac joint • Flexion-extension view is added when ever spinal instability suspected

6. Straight leg raising test should be performed to detect nerve root irritation Even with a soft tissue pain source, SLR can be used as an index of improvement A +ve crossed SLR test has the highest correlation w myelographic finding of a herniated disc Straight leg raising test

7. Causes of back pain • Pain sensitive structures are the supporting bone, articulations, meninges, nerves, muscles, & aponeuroses • Vertebral body despite being short is actually a long bone with end plates of hard bone & a center of cancellous bone • It is innervated by dorsal roots • Periosteum is pain sensitive as is facet joint which have a capsule & meniscus richly innervated w nociceptors

8. Muscular Pain • Most back pains are caused by sprain or strain of the back muscles & ligaments • Pain will be in discrete area & tender to touch • It is of aching quality & may involve muscle spasm • Pain not involved shooting pain

9. Spinal causes • Osteoporosis • Osteomylitis • Herniated Disc • Spondylolisthesis • Spondylolysis • Facet hypertrophy • Ischemia of the spinal cord

10. Osteoporosis is painful due to microfracture Absence of wt bearing due to bed ridden leads to demineralization & fx upon wt bearing Postmenopause & pt Rx with corticosteroid is at risk Other cond r/o w serum protein electrophoresis, sed rate, alkaline phosphatase, ca, x-rays.Rx Biphosphonate, raloxifene Osteoporosis

11. Vertebral osteomyelitis presents as subacute back pain that increases over days to weeks Pain in low back if unRx focal weakness, bowel & bladder problem results Most common in lumbar spine in men over 50 With AIDS younger men & cervical spine affected Osteomyelitis

12. Osteomyelitis • In immunocompetent hosts, Staphylococcus aureus inf most common • Inf involves vertebral bodies, endplates, & disc spaces, spares post elements • In rare cases actinomycosis or coccidiodomycosis, posterior elements involved & spine becomes unstable

13. Vertebral metastases • Vertebral metastasis presents as localized, deep, aching, back pain • If nerves are involved, pain occurs in neural distribution • Thoracic spine is most commonly affected • Epidural spinal cord compression is a medical emergency & pt may present with paraparesis, sensory loss, bowl & bladder involvement

14. On plain film earliest sign of spinal metastasis is erosion of pedicle Over time vertebral body begins to lose height MRI reveals change in signal intensity in vertebral body As tumor progresses, it may be seen invading epidural space & compressing spinal cord Vertebral metastases

15. Facet joint pain • The vertebral bodies have 4 facet joint, 1 pair above & 1pair below • Synovial joints mean they have fluid with in them • Back pain caused by arthritis of the facet joints is mostly midline & may spread to the back & to the flanks • Gets worse with bending backward & side to side

16. Herniated Disc • Intervertebral disc consists of an outer fibrous body called the annulus fibrosus & an inner gel like substance called the nucleus pulposus • It acts as a shock absorber & spacer for the spine giving room for the intervertebral neural foramina which are portals for the exit of the spinal nerves • The nucleus pulposus contains noxious chemicals which can be irritating to nerves

17. Herniated disc-cont- • The intervertebral discs lie between the vertebral bodies. In front is the ant. longitudinal ligament & behind the post. longitudinal ligament & behind that is spinal cord. • Wear & tear can cause annulus fibrosus to weaken allowing bulges of nucleous pulposis • These bulges may protrude out enough to touch the spinal cord causing irritation to nerves • These large disc bulges are called herniation

18. Herniated Disc • With extreme forces these disc bulges may tear the annulus fibrosus & allow leakage of nucleus pulposus • This is observed as sudden sharp pain radiating down the leg • The chemicals of nucleus pulposus can cause swelling of nerves resulting in constant burning pain termed lumbar radiculopathy or sciatica, pain radiating down the leg & feet

19. Types of Herniate Disc • Disc degeneration • Disc prolapse • Disc extrusion • Disc seqestration

20. Radiographic herniated disc

21. Spondylosis • It can be described as arthritis of the spine • The bony surfaces may become roughened & bony spurs may develop & intrude upon the spinal canal

22. Spondylolisthesis • It is a slippage of the vertebra upon one another • The vertebra are usually aligned so that each one is stacked like “legos” so that the spinal canal is a fairly straight tube

23. If there is a slippage, the spinal canal has a kink & is a smaller in that area When spinal stenosis occurs, it squeezes upon the spinal cord This may cause irritation or ischemia of the spinal cord & lead to cramping or aching of the legs Spondylolithesis

24. Grades of Spondylolisthesis

25. Piriformis Syndrome • It is a syndrome of low back & leg pain due to ch. Contracture of the piriformis muscle that causes irritation of sciatic n • Gluteal pain radiates to sciatic nerve • It occurs by compression of nerve between ms. Or ms & pelvis

26. Buttock pain • Common causes are • Piriformis syndrome • Ischial tuberosity inj. • Rupture of gluteal ms.

27. Piriformis Syndrome • It is also called “hip pocket neuropathy” or “wallet neuritis” • Piriformis ms is flat, pyramidal ms that originates from ant surface of sacrum from S2-S4 & sacrotuberous lig passes through the upper part of greater sciatic notch, & inserts on superior surface of great trochanter

28. Treatment of Back Pain • Walking is best exercise • Physical therapy for core stabilization • Spinal manipulation & manual therapy • Analgesics like acetaminophen, NSAID’S, antidepressants • Application of heat or ice • Acupuncture • Corticosteroid injections

29. Treatment of Chronic Back Pain • Treat the cause like in osteomylitis, surgery with antibiotics is used • Vertebral metastasis will respond to high doses of dexamethasone, definitive treatment with radiation & surgery • Osteoporosis treated with Biphosphonate, Robaxifene • Muscle spasms may respond to ms relaxants

30. Back Exercises • Ankle pump • Heel slides • Abdominal contraction • Wall squats • Heel raises • Straight leg raises • Knee to chest stretch • Hamstring stretch • Exercises with swiss ball

31. Epidural space identified w loss of resistance tech or fluroscopy 60-80 mg of triamcilone with 0.25% bupivacaine injected Epidural steroid injection

32. IDET is done using fluoroscopy, a hollow needle containing flexible tube & heating element is inserted into spinal disc The catheter placed in a circle in the annular layer of disc & slowly heated to 194 deg. The heat is meant to destroy the nerve fibers & toughen the disc tissue, sealing any small tear Intradiscal electrothermic therapy

33. Vertebroplasty • Under fluoroscopy, a hollow needle is inserted & a cement is injected to restore the vertebra

34. Kyphoplasty • In kyphoplasty a ballon is inserted through the hollow needle into the fractured bone to restore the height & shape of the vertebra. • Once the ballon is removed, the cement mixture is injected.

35. Kyphoplasty / Vertebroplasty

36. Spondylolithesis

37. Discectomy • A scope is inserted through a small cannula to inspect disc surface • Peri-annular fat is removed & small capillaries are cauterized • Small nerves in the annular fat can be removed with peri-annular tissue

38. GOAL: Freedom From Pain STEP 3 Pain Persists STEP 2 Pain Persists STEP 1 WHO Pain ladder • Step 3: Opioids for moderate-to-severe pain +/- non-opioid +/-adjuvant therapy • Step 2: Opioids for mild- to-moderate pain +/- non-opioid +/- adjuvant therapy • Step 1: Non-opioid +/- adjuvant therapy

39. WHO Pain Ladder • Step 1 Mild (pain rating 1-3) Non opioid + co-analgesics e.g. NSAID+TCA/membrane stabilizer/ms.relax. • Step 2 Moderate (pain rating 4-6) Opioid + Non opioid + co-analgesics Lorcet + NSAID+TCA/memb. Stab./ms. Relax. • Step 3 Severe ( pain rating 7-10) Pure opioids + non-opioids + co-analgesics e.g. Morphine SR + NSAID + above.

40. Opioid combination products

41. Acetaminophen (Tylenol) • MoA: Cox-3 inhibter of PG in the CNS & peripheral pain impulse • Pain indication: Use alone for mild pain • Do not exceed 4 gms / day • Lorcet – 6 tabs/day= 60 mgs morphine • Lortab- 8 tabs / day=40 mgs morphine • Adverse effects: -Lightheadedness, dizziness, hepatotoxicity with high doses & chronic use

42. NSAID’S • Indications: anti-inflammatory, antipyretic, analgesic • Acetylsalicylic acid ( ASA ) irreversibly inhibits platelet • Side effects: Reversible antiplatelet effect, minimal w/ non-acetylated salicylates ( eg Disalcid, Dolobid ) - GI ulceration, less w ibuprofen, etodolac, salsalate, nabumentone - Nephrotoxity – caution in CHF, dehydratation, elderly - Hepatotoxicity: caution in elderly & alcoholics - Avoid in asthmatics & nasal polyps

43. Mechanism of Action • Phospholipids, released from cell membrane are cenverted to Arachidonic acid by phospholipase A2 • Arachidonic acid is acted by lipo-oxygenase to be converted to Leukotrienes • Cyclo-oxygenase acts on Arachidonic acid to form Prostaglandin endoperoxides which are converted to Prostaglandin G & by isomerase into Prostaglandin E2, Prostaglandin D2, & F2 alpha • Prostaglandin H is formed from prostaglandin endoperoxides & converted by Thromboxane to Thromboxane A2 & Thromboxane B2. • Prostacyclin synthetase converts prostaglandin endoperoxides to Prostacyclin ( PGI )

44. Co-analgesic Pain Medications • Antiepileptics • Antidepressants • Muscle Relaxants • Anesthetics • Corticosteroids • Psychostimulants • Substance P inhibitors • Alpha-2 agonists • Neuroleptics • Antiarryhmics • Benzodiazepines

45. Antiepileptics • MOA: Block Na+ & Ca+ channels>>inhibits release of glutamate>> stabilizes neural memb. • Uses: Trigeminal neuralgia, peripheral neuropathies, herpetic neuralgia, phantom limb pain, migraines. • Aniepileptics: Gabapentin, Carbamazepines, topiramate, phenytoin, oxycarbamazepine, pregabalin • Comared to TCA’s: -equally efficacious in painful DN -some AED may be more expensive - differences in safty profile - synergy with AED plus TCA

46. Gabapentin (Neurontin) • MOA: a 2-delta ca+ channel subunit modulator • Uses: Peripheral neuropathic pain, phantom limb pain, CRPS, post herptic & trigeminal neuralgia. • Doses: adjust for elderly & renal failure -range 300- 3600 mg /day divided in 3-4 doses • Somnolance, dizziness, constipation, fatigue, peripheral edema, difficulty concentrating

47. Pregabalin (Lyrica) • MoA: a 2 delta Ca+ channel subunit modulator • Pain uses: Diabetic & post herpetic neuropathic pain at doses 300-600 mgs/day divided 2-3 X. • Other neuropathic pain conditions, fibromyalgia, generalized anxiety disorder. • Compared to gabapentin: • Bioavailability remains 90% at all doses • Time to effective dose (150-300mg/day) is 1-3days • Class v schedules drug.

48. Carbamazepine ( Tegretol) • MoA: Na+ & Ca+ channel blockade • Pain uses: trigeminal neuralgia, glossopharyngeal neuralgia, DPN • Dosing: 200-1000mg divided 2-3X (with food) • Side effects: N & V, dizziness, sedation, transient leukopenia, hepatic toxicity, thrombocytopenia, diplopia, hyponatremia, rash, Steven-Johnsons syndrome.

49. Tricyclic antidepressants • MoA: inhibits re-uptake of NE, SE, antihistamine • Pain indications: Painful neuropathies, Phantom limb pain, migraine prevention • Dose: start low & adjust every 2- 3 days • Drug interactions - caution with other anticholinergics/serotonergics - CYP2D6 substrate ( all TCA’s) - CYP3A4 substrate ( Elavil )

50. Choice of A TCA • Amitriptyline ( Elavil) - most widely studied - more side effects- hang over effect. • Doxepin ( Sinequan ) - similar to Elavil, but shorter duration of sedation • Desipramine ( Norpramin ), Nortriptyline ( Pamelor) - may cause insomnia - less anticholinergic effect - Desipramine may cause orthostatic hypotension