In Thailand, lumbar Radiculopathy is managed by physical medicine & rehabilitations. Lumbar radiculopathy is pain, paresthesia, and weakness in a dermatomal pattern caused by irritation or compression of a lumbar nerve root, most often L5 or S1. Lifetime prevalence is approximately 3-5% in adults, with annual incidence near 1-2% in working-age populations.
Lumbar radiculopathy (ICD-10: M54.16-M54.18 and M51.16-M51.17 for disc-related causes) is a clinical syndrome of pain, paresthesia, sensory loss, weakness, and reduced reflexes in the distribution of one or more lumbar or sacral nerve roots, caused by compression or chemical irritation of the affected root. The most commonly affected roots are L5 and S1, which together account for over 90% of cases. The L5 root supplies the dorsum of the foot and the great toe and powers ankle dorsiflexion and great-toe extension; the S1 root supplies the lateral foot and powers ankle plantarflexion and the ankle reflex; the L4 root supplies the medial calf and powers the quadriceps and knee reflex. Mechanisms include disc herniation (the most common cause under 50), lumbar foraminal or central stenosis, spondylolisthesis, facet hypertrophy, synovial cysts, vertebral fracture, infection (discitis-osteomyelitis), and tumor (metastatic disease, schwannoma).
The key symptoms of Lumbar Radiculopathy are: Unilateral leg pain radiating from the buttock down the back or lateral thigh, past the knee, into the calf, foot, or toes, in a dermatomal pattern., Sharp, electrical, burning, or shooting pain quality that often dominates over any associated low back pain., Pain worse with sitting, forward bending, coughing, sneezing, or Valsalva; often relieved by lying down or in some patients by walking., Numbness or paresthesia (tingling, pins-and-needles) in the dermatomal distribution: dorsum of foot and great toe (L5), lateral foot and heel (S1), medial calf (L4)., Weakness in muscles supplied by the affected root: ankle dorsiflexion and great-toe extension (L5), plantarflexion and toe-walking (S1), knee extension (L4)., Foot slap, tripping, or catching of the foot on uneven ground in moderate to severe L5 radiculopathy with foot drop., Positive straight-leg-raise test reproducing the patient's leg pain at 30-70 degrees of hip flexion (sensitivity 80-91%, specificity 26% for disc herniation)..
Diagnosis is clinical, anchored in a careful history and neurological examination. Key history elements are onset (acute vs gradual), pain location and radiation pattern, exacerbating positions, response to walking, presence of red flags (fever, weight loss, malignancy history, intravenous drug use, recent procedure, anticoagulation, age over 70 with low-trauma onset, bowel or bladder symptoms), and prior treatments. Examination tests sensation in L4-S1 dermatomes, motor strength of ankle dorsiflexors (L4-L5), great-toe extensor (L5), plantarflexors (S1), and quadriceps (L4), and reflexes (knee for L4, ankle for S1). Provocative tests include straight-leg raise (sensitive ~80-91% for disc herniation), crossed straight-leg raise (more specific), femoral nerve stretch test (for L2-L4), and slump test. Imaging is not required for typical presentations within the first 6 weeks unless red flags or progressive neurological deficits are present. When indicated, MRI without contrast is the modality of choice (ACR Appropriateness Criteria, North American Spine Society guidelines), demonstrating disc herniations, stenosis, spondylolisthesis, tumors, and infections. CT is reserved for patients who cannot undergo MRI or for assessing bony detail before surgery. Electrodiagnostic studies (EMG and nerve conduction) are useful at 3-6 weeks when the diagnosis is unclear, multiple roots are suspected, or polyneuropathy must be excluded; they are not a routine first-line test. Laboratory studies (CBC, ESR, CRP, calcium, alkaline phosphatase, PSA) are added when infection, malignancy, or metabolic disease is suspected. The diagnostic workup also evaluates psychosocial factors (depression, anxiety, fear-avoidance, occupational dissatisfaction) that strongly influence outcome.
Most lumbar radiculopathy resolves substantially with non-operative care: 60-90% of patients with disc-related disease report meaningful improvement in pain and function by 6-12 weeks. Persistent radiculopathy beyond 12 weeks affects 10-30%, and a smaller subset (5-15%) develops chronic radicular pain. The SPORT trial (Weinstein NEJM 2008) showed faster pain relief with surgery but similar 2-year outcomes between surgical and non-operative cohorts, with substantial crossover. Predictors of poor outcome include severe baseline disability, prolonged symptoms before treatment, depression, fear-avoidance, smoking, obesity, workers' compensation status, and severe sensorimotor deficit. Stenosis-related radiculopathy in older adults has a more chronic course; decompression surgery produces durable improvement in walking distance and leg pain in 60-80% at 5 years. Recurrence after microdiscectomy is approximately 5-10% at 2 years. Long-term outcomes are best when treatment integrates physical, behavioral, and pharmacological components and addresses modifiable factors (weight, smoking, conditioning, mood).
Refer to physical medicine and rehabilitation, pain medicine, or spine surgery for severe or persistent radicular pain beyond 6 weeks of optimal non-operative care, progressive neurological deficit, or red-flag features. Emergency neurosurgical or orthopedic spine referral is required for cauda equina syndrome, acute foot drop, or suspected epidural abscess. Multidisciplinary spine programs improve outcomes and reduce inappropriate surgery.
Find specialists →Acute pain typically improves substantially within 2-6 weeks; most non-operative cases approach baseline function by 8-12 weeks. After microdiscectomy, pain often improves within days and return to sedentary work occurs at 2-4 weeks; manual work at 6-12 weeks. After laminectomy with fusion, recovery extends to 3-6 months. Foot-drop strength may continue improving for 6-12 months and may not fully recover when motor deficits were severe at presentation.
Once acute pain settles (typically within 2-4 weeks), aim for 150 minutes per week of moderate aerobic activity (walking, swimming, stationary cycling) plus twice-weekly core stabilization and resistance training under physical-therapy guidance. McKenzie-style directional preference exercises (often extension-biased for centralizing disc-related pain) and graded return to flexion-rotation activities are guided by symptom response. Avoid heavy unsupported lifting and high-impact activities until pain-free.
Choose a physiatrist, pain specialist, or spine surgeon affiliated with a high-volume spine program. Confirm experience with the specific procedure being considered (microdiscectomy, fluoroscopic injections) and access to multidisciplinary support (physical therapy, behavioral medicine). For older adults, prefer programs with experience in osteoporotic spine surgery.
Medically reviewed by AIHealz Medical Editorial Board · May 13, 2026
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