What are the implications of experiencing numbness, particularly in the big toe and second toe, with difficulty dorsiflexing (moving up) but able to plantarflex (move down), a week after undergoing a microdiscectomy (microdiscectomy) surgery?

Post-Microdiscectomy Toe Numbness and Weakness

You are experiencing symptoms consistent with L5 nerve root dysfunction (foot drop pattern), which represents either incomplete nerve decompression, nerve root injury during surgery, or postoperative nerve swelling—this requires urgent neurosurgical evaluation within 24-48 hours to determine if reoperation is needed.

Clinical Significance of Your Symptoms

Your specific pattern of weakness is highly concerning:

• Inability to dorsiflex toes (move up) while retaining plantarflexion (move down) indicates L5 nerve root compromise 1
• The L5 nerve root controls the extensor hallucis longus (big toe dorsiflexion) and extensor digitorum longus (other toe dorsiflexion) 1
• Numbness with cold sensation (dysesthesia) affecting the big toe and second toe follows the L5 dermatome distribution 1
• These symptoms appearing one week post-surgery suggest either residual compression, nerve injury during the procedure, or postoperative hematoma/swelling 1

Immediate Assessment Required

Contact your neurosurgeon urgently for evaluation of:

• New or worsening neurological deficit, which occurs in 1.3-3.0% of microdiscectomy cases and may require intervention 1
• Direct nerve root injury, reported in 0.9-2.6% of cases depending on technique 1
• Postoperative hematoma, which occurs in 0.5-1.2% of cases and can cause progressive neurological deterioration 1
• Recurrent or residual disc herniation, affecting 3.1-4.4% of patients, which may require reoperation 1

Expected vs. Concerning Trajectory

Normal postoperative course:

• Some numbness and tingling can persist for weeks to months as nerves recover from preoperative compression 2, 3
• Gradual improvement in sensation and strength should occur over 6-12 weeks 2

Your concerning features:

• Motor weakness (inability to dorsiflex) is more worrisome than pure sensory symptoms 1
• One week post-surgery is a critical window where complications like hematoma or incomplete decompression become apparent 1
• The combination of motor and sensory deficits suggests significant nerve compromise requiring evaluation 1

Potential Causes and Next Steps

Your surgeon needs to evaluate for:

• Incomplete decompression: Residual disc fragment or inadequate nerve root decompression may require revision surgery 3, 1
• Postoperative hematoma: MRI can identify epidural hematoma compressing the nerve root, which may require urgent evacuation 1
• Nerve root injury: Direct surgical trauma to the L5 nerve root, though recovery may still occur with conservative management 1
• Postoperative swelling: Nerve root edema can cause temporary dysfunction but should improve over weeks 2

Diagnostic Workup Needed

Your neurosurgeon will likely order:

• Urgent MRI of lumbar spine to evaluate for hematoma, residual disc herniation, or nerve root compression 1
• Physical examination documenting motor strength (0-5 scale) in toe dorsiflexion, ankle dorsiflexion, and sensory distribution 1
• Comparison to preoperative neurological status to determine if this represents new deficit or persistent preoperative symptoms 2, 3

Management Options

Based on findings:

• If residual compression or hematoma: Reoperation within days may be necessary to prevent permanent nerve damage 1
• If nerve root injury without compression: Conservative management with close monitoring, as some recovery may occur over 3-6 months 1
• If postoperative swelling only: Observation with serial examinations, expecting gradual improvement 2

Prognosis Considerations

• Early intervention (within days to weeks) for correctable causes offers the best chance of neurological recovery 1
• Delayed treatment of ongoing nerve compression can result in permanent motor weakness 1
• Even with appropriate management, complete recovery of motor function is not guaranteed if nerve injury occurred 1
• Reoperation rates after microdiscectomy range from 3.7-10.2% depending on technique, with recurrent herniation being a common indication 1

Do not wait for your scheduled follow-up appointment—contact your surgeon's office today to report these symptoms and request urgent evaluation.