NeuroSurgery Case: Low Back Pain

Salient Features A 45 year old office secretary Sudden snap and pain in the left lumbar area while trying to lift a box load of papers. Pain was subsequently felt in the posterolateral aspect of the right thigh and leg down to the right heel. Admitted initially and placed on bed rest and pelvic traction for 3 weeks with no improvement.

Neurological examination revealed the following findings: BP: 130/80, PR: 88, RR: 18, T: 37 – Patient in left lateral decubitus with the right knee flexed – Numbness in the back of the right calf muscle, lateral heel, foot and toe – Weakness of the right plantar flexion of foot and toes – Difficulty walking on toes on the right – Atrophy of right gastrocnemius and soleus muscles – Both knee jerks are (++) – Right ankle jerk absent, left ankle jerk is (++) – No babinski bilaterally – The rest of the neurological examination is within normal limit

1. What is the nature of the problem of the patient? What is the anatomical explanation of the symptoms of the patient?

Nature of the problem Based on the history of the patient (heavy lifting, while bent at the waist), the most probable problem is due to an injury to the spinal cord, more specifically, a lumbar disc herniation. A tear in an annulus fibrosus allows the nucleus pulposus to squeeze into the spinal canal. If a nerve root is compressed by the disc material, there can be pain, numbness, and weakness in the areas supplied by the nerve (often down the back of a leg).

Depending on the nerve root that is compressed, the patient may present with the following symptoms: Disc Level Root Comp. Weakness Reflex Involvement Sensory Loss Pain Distribution L3-L4 L4 quadriceps, tibialis anterior knee jerk medial knee and shin anterior thigh L4-L5 L5 extension of big toe no significant big toe back of thigh, lateral calf L5-S1 S1 gastrocnemi us (ankle plantar flexion) Achilles lateral foot and heel back of thigh and calf

Sign/SymptomAnatomic explanation Patient in left lateral decubitus with the right knee flexed right L2 OK, not compressed Numbness in the back of the right calf muscle, lateral heel, foot and toe right L5-S1 compression Weakness of the right plantar flexion of foot and toes right S1 compression Difficulty walking on toes on the rightright L5-S1 compression Atrophy of right gastrocnemius and soleus muscles Compressed L5-S1 leads to muscle inactivity Both knee jerks are (++)Both L2-4 OK Right ankle jerk absent, left ankle jerk is (++) Left S1 not compressed, right S1 was compressed No Babinski bilaterallyLMN disorder The rest of the neurological examination is within normal limit The problem lies in right L5-S1 compression

Anatomic Problem Right L5-S1 nerve root compression due to lumbar disc herniation Lumbar Radiculopathy (affecting L5-S1) – If a nerve root is compressed by the disc material, there can be pain, numbness, and weakness in the areas supplied by the nerve

2. What is the difference between a radicular and a myelopathic manifestations and what is the significance of each in relation to the signs and symptoms and clinical management?

Radiculopathy vs Myelopathy  when a disc or osteophytic protrusion compresses the adjacent nerve roots = radiculopathy when a disc or osteophytic protrusion compresses the spinal cord = myelopathy

Radiculopathy pain + paresthesia + root signs Pain = (sharp, stabbing, worse on coughing) + (constant deep ache radiating over shoulders and down the arm) : follows a nerve root distribution Paresthesia: numbness or tingling follows a nerve root distribution

Radiculopathy Root signs: – sensory loss—pin prick deficit in the appropriate dermatomal distribution – muscle (lower motor neuron) weakness and wasting in appropriate muscle groups – reflex impairment or loss – trophic change—in long standing root compression, skin becomes dry, scaly, inelastic, blue, and cold

Myelopathy Compression causes segmental damage at the involved level and long tract signs below level Arms: LMN signs and symptoms; UMN signs and symptoms below the level of the lesion (e.g. muscle weakness and wasting, diminished reflexes in some joints, hyperreflexia in others, all corresponding to the nerve distribution)

Myelopathy Legs: UMN signs and symptoms; difficulty in walking due to stiffness; “pyramidal” distribution weakness, increased tone, clonus and extensor plantar responses; sensory symptoms and signs are variable and less prominent Sphincter disturbance is seldom a prominent early feature

RadiculopathyMyelopathy Etiology Compression of the spinal nerve roots Compression of the spinal cord (direct pressure/ vascular impairment) Signs and symptoms pain + paresthesia + root signs on nerve root distribution  Arms: LMN signs and sxs; UMN signs and sxs below the level of the lesion  Legs: UMN signs and symptoms  Sphincter disturbance is seldom a prominent early feature Clinical management Conservative  Analgesics  Immobilization – soft collar, Philadelphia collar, Milwaukee  Physical therapy o Manual traction o Cervical muscle exercises Surgery options:  Anterior decompression and fusion  Laminectomy  Foraminotomy