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Sciatica: When to image. When to refer. Juanita Halls M.D. Internal Medicine October 10, 2007. No financial disclosures. Objectives. Understand when to perform imaging on patients presenting with sciatica Understand when to refer patients with sciatica to a spine surgeon. Case 1.
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Sciatica: When to image. When to refer. Juanita Halls M.D. Internal Medicine October 10, 2007
Objectives • Understand when to perform imaging on patients presenting with sciatica • Understand when to refer patients with sciatica to a spine surgeon
Case 1 • 58 yo healthy female presents January, 2007 with 6 week history of achy LBP, R>L with episodes of pain shooting down back of thighs to calves and occasional numbness in foot • No preceding injury, heavy lifting, etc • No weakness, bladder or bowel dysfn • No systemic sx e.g. fever/sweats/weight loss
PMH • Hypertension on lisinopril/HCTZ • s/p hysterectomy • Takes MVI and Calcium/vitamin D • Otherwise healthy, non-smoker • Screening: • Routine PE 10/06 • mammogram 10/05, ordered 10/06 but not done • Flex sig negative 1999, FOBT negative 10/06 (colonoscopy not covered by insurance)
Exam • No spinal tenderness or deformity • Mild decrease extension with pain • Mild decrease flexion without pain • Positive SLR bilaterally at 60o • DTR: 2+ knee and 1+ ankle bilaterally • Motor: 5/5 in LE • Sensory: Intact
Imaging • L/S spine films: multilevel degenerative disk and joint disease • No labs done
Dx/ Rx • “Sciatica with no worrisome symptoms and negative spine X-ray” • Home exercises • PT referral • Ice or heat • No lifting • Naproxen and Tylenol #3 • RTC 2 months, sooner if not improving
2 months later • Had cancelled PT because pain resolved with home exercises and Naproxen • Now 3 week history of increased right sided LBP radiating to right foot • Paresthesia of right ankle • No weakness or bladder/bowel dysfn • ↑ with sitting and at night
Exam • No spinal tenderness • SLR negative on left, positive at 60o on right • DTR: symmetrical • Motor: 5/5
Plan • MRI offered but patient declined • Diclofenac (was having side effects with naproxen) • PT referral • Spine clinic referral
4 weeks later (3 months after initial presentation) • Seen in Spine clinic: • Pain had gotten better, now worse again and interfering with sleep • No systemic symptoms • Exam: • No change except minimal tenderness • Positive SLR/Lasegue maneuver • DX: Probable HNP • Plan: MRI
2 Weeks later(3 ½ months after presentation) • MRI competed and I am paged by the Spine clinic physician late Friday afternoon
MRI reading • Large osseous mass involving right iliac wing and central and right portions of S1 and S2 vertebra with soft tissue extension obliterating right L5, S1 and S2 neural foramen. • Second osseous mass in body of T12 • Most likely represents metastatic disease
10 days later • CT guided biopsy: • Large B cell lymphoma
Low Back Pain • Low back pain • 84% of adults experience LBP • 2.5% of medical visits • Total cost in US: $100 Billion per year • <5% have serious pathology • 5% have sciatica • Annual incidence of sciatica is 5 per 1000
Definition of sciatica • Pain, numbness, tingling in distribution of sciatic nerve • Radiation down posterior or lateral leg to foot or ankle • If radiation below knee – more likely radiculopathy with impingement of nerve root
Etiology of sciatica • Mechanical • Pyriformis syndrome • HNP • Spondylolisthesis • Compression fracture • Neoplastic (0.7% of LBP) • Infectious (0.01% of LBP)
Questions to ask • Is there evidence of systemic disease? • Is there evidence of neurological compromise?
Clues on history to suggest systemic disease • Hx of cancer No • Age > 50 Yes • Unexplained weight loss No • Duration > 1 month Yes • Night time pain Yes • Unresponsive to conservative rx +/- • Pain not relieved by lying down +/-
Exam • Back exam • ROM • Palpate for tenderness • SLR • Neuro exam • If suspicious history • Breast or prostate exam • Lymph node exam
Straight leg raising Passive lifting of the leg with the knee extended produces pain radiating down the posterior or lateral aspect of the leg, distal to the knee and usually into the foot. Dorsiflexion of the foot (Lasegue's test) will exacerbate these symptoms
Finding Sensitivity, percent Specificity, percent + LR Negative LR Motor examination: Weak ankle dorsiflexion 54 89 4.9 0.5 Ipsilateral calf wasting 29 94 5.2 0.8 Sensory examination: Leg sensation abnormal 16 86 NS NS Reflex examination: Abnormal ankle jerk 48 89 4.3 0.6 Other tests: Straight-leg raising maneuver 73-98 11-61 NS 0.2 Crossed straight-leg raising maneuver 23-43 88-98 4.3 0.8 Sensitivity/specificity for radiculopathy, in patients with sciatica* LR:
Imaging indications • Progression of neurological findings • Constitutional symptoms • Hx of traumatic onset • Hx of malignancy • <18 or > 50 • Infection risk (IVDU, immunocompromise, fever) • Osteoporosis
Imaging – L/S spine films • If risk factor or no better in 4-6 weeks • May be able to detect: • Tumor (sensitivity 60%) • Infection (sensitivity 82%) • Spondyloarthropathy • Spondylolisthesis • Also consider Labs: ESR and/or CRP if risk for infection • If negative: conservative rx for 4-6 weeks
Imaging - MRI • If progressive neurological deficit, high suspicion of cancer or infection, or 12 weeks of persistent pain • May be able to detect: • Tumor (sensitivity 83-93%) • Infection (sensitivity 96%) • HNP (sensitivity 60-100%) • Spinal stenosis (sensitivity 90%)
Malignancy and sciatica • O.7% of LBP due to malignancy • Non-Hodgkin’s lymphoma • 10% have CNS involvement • Sciatica is uncommon and occurs late • Very rare for sciatica to be presenting feature
Case 2 • 49 yo healthy female presents February, 2007 with recurrent LBP radiating to right buttock and shooting to posterior thigh and lateral calf. • Numbness of bottom of foot • No weakness, bladder or bowel dysfn • No systemic sx e.g. fever/sweats/weight loss • ↑ prolonged sitting, getting up, bending • ↓ walking, lying down
Previous history • 4 months previous had ER visit for acute LBP radiating to right buttock after bending over in Yoga class and treated with PT and pain meds • 2 months previous after 6-7 PT sessions reported “much better” • PMH: No meds, non-smoker
Exam • DTR’s 2+ at knee and ankle • Motor 5/5 in LE • No spinal tenderness • SLR negative bilaterally
Treatment • PT • If not improving, get MRI and/or refer to spine clinic
5 weeks later • No better and MRI ordered and referred to spine clinic
MRI reading • L5-S1 disk protrusion contacting right S1 nerve root
Spine clinic visit next day • Hx: same plus pain increases with cough/sneeze • Exam: • Tender inferior to right piriformis muscle • ↓ sensation to light touch right S1, PP normal • DTR: 2+ knees and left ankle, 1+ right ankle • Negative SLR • Prone press up – pain in buttock • Dx: Radiculopathy with HNP L5-S1
Spine clinic treatment • Right S1 diagnostic and therapeutic transforaminal steroid injection • PT and/or chiropracter • Oxycodone • Neurontin
8 weeks later(3 months after initial presentation) • s/p 2 injections, PT, Chiropracter • Still severe pain and now weakness right leg with stairs • Referred to spine surgeon
Spine surgeon • Exam: • SLR positive/ Lasegue positive on right • DTR: 1+ left ankle 0 right ankle • “You should have been here within 6 weeks of onset of sciatica symptoms” • Recommends: L5-S1 microdiskectomy • Outpatient procedure with epidural • 95% get relief of pain • 3% risk of re-herniation
When to refer to spine surgeon • Cauda equina syndrome • Neuro motor deficit • Persistent severe sciatica after conservative treatment
Timing of referral for diskectomy • Optimal timing is not clear • No consensus on how long conservative treatment should be tried • Sciatica improves within 3 months in 75% of patients (95% at one year)
Surgery vs Prolonged Conservative Treatment for Sciatica • Peul, et al NEJM May 31, 2007 • 283 patients with 6-12 wk of severe sciatica and HNP on MRI • Randomized to: • early surgery (microdiskectomey) vs • conservative therapy with surgery if needed • Primary outcomes: • Subjective pain and disability scores • Perceived recovery
Outcomes of study • Surgery grp: 89% surgery at mean 2.2 weeks • Conservative grp: 36% surgery at mean 4½ months • At 1 year: no difference in pain or disability score or perceived recovery (95% in both grps) • Pain relief and perceived recovery faster in surgery group • Median time to full recovery 4 vs 12 weeks • Max difference in pain score <20 mm on 100 mm scale