This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of low back pain

May, Todd J.

English

University of Missouri: MOspace

Chronic Low Back Pain Page 1 of 6    7.18.11 LOW BACK PAIN   Background   1. Definitions  o Pain, muscle tension, or stiffness between the lower costal margin and gluteal folds o Chronic: > 3 mo duration and causing disability1 o Recurrent: acute episode in a pt. recovered from prior episode 2. General information  o Second most common reason for visit to PCP o Second leading cause of absenteeism from work o Usually represents end result of chronic flexion injury & deconditioned musculoskeletal elements  Pathophysiology    1. Pathology  o Multiple structures of lumbar spine have sensory input making anatomical diagnosis difficult o Many sources of pain: muscle strain, ligament sprain, small tears of annulus fibrosis, facet joint arthritis, disc bulges1  70-80% mechanical sprain/strain, facet dz  4% disc herniation  4-7% osteoporotic fracture and spinal stenosis  1% other causes 2. Risk factors  o Work requiring heavy labor/awkward positions o Age > 45 yo o Prior episode of back pain o Obesity and smoking 3. Morbidity/mortality  o No mortality o Significant morbidity secondary to lost work time/cost of treatment   Costs   Direct: $20-40 billion  Indirect: $100 billion  Pts. out of work 1 year have 10% chance of returning to work  Diagnostics  1. History  o Location, radiation o Severity using standard pain scale o Numbness, weakness, stiffness, mobility limitation o Temporal factors, prior episodes, trauma o Aggravating/alleviating factors o Assess red flags (bowel/bladder control, bilateral leg weakness, saddle numbness, fever, unrelenting night pain or pain at rest, below knee numbness, progressive Chronic Low Back Pain Page 2 of 6    7.18.11 neurological deficit, unexplained weight loss, history of cancer or strong suspicion of current cancer, history of osteoporosis, immunosuprression, substance abuse, trauma)1 2. Physical exam  o Gait: leaning to painful side + circumduction suggest hip pathology o Posture: accentuation of normal lordotic curve suggests muscle spasm, disc disease o Strength   Standing on toes (gastrocnemius)  Heel-walk tests (dorsiflexors)  Repeated toe raises to elucidate fatigability (sensitive for nerve root irritation)  o Inspection   Specific areas of tenderness, swelling, redness, rash, spasm  Reflex hammer to percuss spinous processes: localizes bony or disc process o Reflexes   Patellar (L2-L4) & Achilles (L5-S2) decrease with nerve impairment   Bilateral involvement suggests massive central disc herniation or systemic illness  o Sensation   Nerve root involvement/dermatomes correlate with motor or reflex findings  Rectal exam for tone, perianal sensation o Maneuvers   Straight leg raise: lift leg to limit of comfort with knee extended/foot dorsiflexed   Positive: pain radiates from back into leg below knee  Crossed straight leg test: as above with uninvolved leg   Positive: pain in leg with radicular symptoms  Sitting knee-extension: extend leg at knee with pt. sitting/hip & knee flexed 90 deg   Positive: back pain reproduced o Waddell's signs   If 3 or more present suggests high likelihood psychogenic component to pain  Overreaction to exam  Simulated testing: patient reports pain with axial loading or rotation of the spine in one plane  Distraction testing: sitting straight leg raise  Superficial variable tenderness  Motor/sensory findings not explained anatomically o Abdomen/chest   Tenderness, masses, bruits, bowel sounds, CVA tenderness, RUQ tenderness 3. Diagnostic testing  Chronic Low Back Pain Page 3 of 6    7.18.11 o Laboratory   CBC, ESR if suspicion of cancer o Diagnostic imaging   Routine imaging not recommended during initial 4-6 wk of symptoms unless underlying condition suspected (SORT-C)1  X-ray   Thoracic/lumbar/sacral if indicated by history  Consider oblique view if spodylolysis suspected  MRI   Preferred diagnostic test when indicated10  Use emergently if: o Suspicion of cauda equina syndrome o Suspicion of disc, epidural, bony infection o Rapidly worsening neurological deficit o Suspect malignancy with cord impingement  Differential Diagnosis  1. Key Differential Diagnoses o Pyriformis Syndrome o Herniated Disk  o Fractures o Facet Syndrome o Spinal Stenosis 2.  Extensive Differential Diagnoses o Pelvic or intra-abdominal pathologies o Spondyloarthropathies o Tumor o Infection o Claudication  Therapeutics : There are no studies comparing treatment modality to treatment modality 1.  Exercise- slightly effective at improving pain and function in adults2 2.    Viniyoga, may provide short term pain relief 1 3.    Multidisciplinary team-with a physician and at least one additional intervention (vocational, psychological,social ) returns patient to work 5 weeks earlier and reduces recidivism rates for 5 years1 4.  Medications o TCA-no difference with placebo3 o Muscle Relaxants-possible short term relief and may be helpful for exacerbations;  no evidence to support long term use1 o Opiods-centrally acting and provide pain relief; use in chronic back pain is controversial; Risk include tolerance, addiction, abuse, constipation, drowsiness, memory impairment, hyperalgesia4 o Tramadol-[mixed receptor agonist/antagonist] may be helpful in short term treatment;  less risks compared to opiods (long term studies are lacking)1 Chronic Low Back Pain Page 4 of 6    7.18.11 o NSAIDS-helpful for short term treatment of pain; no more effective than acetaminophen; Risks include renal, GI, cardiovascular (esp COX-2) complications5 o Acetaminophen-first line and safe (SORT-A)1 o Antepileptics-Only gabapentin shown to provide short term relief in LBP with radiculopathy1 o Antidepressants-no class benefit with SSRI’s; exception: duloxetine found to provide pain relief3 5. Manipulation- improved pain relief;  no functional advantage over other commonly used treatments; allows for less medication use than other treatment options6 6. Accupuncture- effective in reducing pain, improve functioning in short term as adjunctive to other treatments1 7. Injections-no evidence for or against; many options including epidural steroid, facet blocks, nerve roots and tender/trigger point injections7 8. Mental Health-cognitive behavioral therapy, progressive relaxation provide short term pain control8 9. Herbal Products-short term relief1 o oral   Harpagophytum Procumbens-devil’s claw 50 mg   Salix Alba-white willow bark 120 and 240mg o topical   Capsicum Frutescns-Cayenne plaster  Follow-Up   1. Return to office  o Patient off of work: 2-3 days o Moderate pain: 1 wk o Symptoms improve: PRN 2. Refer to specialist  o No improvement in 2-3 wk, consider:   Physical therapy  Non-surgical back specialist 3. Psychiatrist if psychogenic component Admit to Hospital o Recommendations / urgency  Prognosis  1. Four interventions with adequate data:11 o Analgesics: less pain that placebo in chronic back pain over 10 weeks o Herbal medicine: less pain than placebo in acute back pain over one week o Muscle relaxants: less pain than placebo in acute back pain over one week o NSAIDs: less pain than placebo in both acute and chronic pain over average of six weeks 2. Acute LBP 12 o Mean 58% reduction within one month o Mean 58% reduction in disability within one month o 68-86% return to work within one month Chronic Low Back Pain Page 5 of 6    7.18.11 o 66-84% cumulative risk of at least one recurrence within 12 months 3.  Chronic LBP12 o Pain level, disability and return to work remain essentially constant at 3 and 12 months  Patient Education 1. National Library of Medicine-http://www.nlm.nih.gov/medlineplus/backpain.html 2. Family Doctor.org-http://familydoctor.org/online/famdocen/home/common/pain/disorders/117.html 3. Mayo Clinic-http://www.mayoclinic.com/health/back-pain/DS00171 4. MD Consult-http://www.mdconsult.com/das/patient/body/240487363-2/0/10041/9441.html 5. AFP-http://www.aafp.org/afp/20000315/1789ph.html  References  1. University of Michigan Health System. Acute low back pain. Ann Arbor (MI): University of Michigan Health System; 2003 Apr [rev. Oct 2004]. 13 p.1. Allen RL MD MPH, Hulbert K MD; Chronic Low Back Pain: Evaluation and Management; AFP; 2009;79(12):1067-1074 2. Hayden J, van TulderMW,Malmivaara A, Koes BW. Exercise therapy for treatment of non-specific low back pain. Cochrane Database of Systematic Reviews 2005, Issue 3. Art. No.: CD000335. DOI: 10.1002/14651858.CD000335.pub2. 3. Urquhart DM, Hoving JL, Assendelft WJJ, Roland M, van Tulder MW. Antidepressants for non-specific low back pain. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD001703. DOI: 10.1002/14651858.CD001703.pub3. 4. Deshpande A, Furlan AD, Mailis-Gagnon A, Atlas S, Turk D. Opioids for chronic low-back pain. Cochrane Database of Systematic Reviews 2007, Issue 3. Art. No.: CD004959. DOI: 10.1002/14651858.CD004959.pub3. 5. Roelofs PDDM, Deyo RA, Koes BW, Scholten RJPM, van Tulder MW. Non-steroidal anti-inflammatory drugs for low back pain. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD000396. DOI: 10.1002/14651858.CD000396.pub3. 6. Assendelft WJJ, Morton SC, Yu EI, Suttorp MJ, Shekelle PG. Spinal manipulative therapy for low-back pain. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD000447. DOI: 10.1002/14651858.CD000447.pub2. 7. Staal JB, de Bie R, de Vet HCW, Hildebrandt J, Nelemans P. Injection therapy for subacute and chronic low-back pain. Cochrane Database of Systematic Reviews 2008, Issue 3. Art. No.: CD001824. DOI: 10.1002/14651858.CD001824.pub3. 8. Henschke N, Ostelo RWJG, van Tulder MW, Vlaeyen JWS, Morley S, Assendelft WJJ, Main CJ. Behavioural treatment for chronic low-back pain. Cochrane Database of Systematic Reviews 2010, Issue 7. Art. No.: CD002014. DOI: 10.1002/14651858.CD002014.pub3. 9. Gibson JNA,Waddell G. Surgery for degenerative lumbar spondylosis. Cochrane Database of Systematic Reviews 2005, Issue 10. Art. No.: CD001352. DOI: 10.1002/14651858.CD001352.pub3. Institute for Clinical Systems Improvement: http://www.icsi.org/guidelines_and_more/gl_os_prot/musculo-skeletal/low_back_pain/low_back_pain__adult_5.html. Chronic Low Back Pain Page 6 of 6    7.18.11 11. LA Machado et al. Analgesic effects of treatments for non-specific low back pain: a meta-analysis of placedbo-controlled randomized trials. Rheumatology, 2009; 48: 520-527. 12. Pengel LHM, Herbert RD, Maher CG, Refshauge KM. Acute low back pain: systematic review of its prognosis. BJM 2003;327:323.  The views expressed in this article are those of the author and do not necessarily reflect the official policy or position of the Department of the Navy, Department of Defense, or the United States Government  I am a military service member.  This work was prepared as part of my official duties.  Title 17 U.S.C. 105 provides that 'Copyright protection under this title is not available for any work of the United States Government.'  Title 17 U.S.C. 101 defines a United States Government work as a work prepared by a military service member or employee of the United States Government as part of that person's official duties.   Author:  Todd J. May, DO, FAAFP, CDR, MC, USN, Camp Pendleton Naval Hospital, CA  Editor:  James W. Haynes, MD, University of TN – Chattanooga FPR   

Low back pain

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Low back pain

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