A 35-year-old male undergoes transfemoral (above-knee) amputation following trauma. Six weeks later, he complains of burning, shooting pain in the phantom foot. The mechanism of phantom limb pain is best explained by:

• A Neuroma formation at the cut end of the sciatic nerve causing ectopic discharges
• B Cortical reorganization in the somatosensory cortex combined with peripheral and central sensitization ✓
• C Reflex sympathetic dystrophy of the residual limb
• D Deep venous thrombosis of the residual limb vasculature

Explanation

Phantom limb pain (PLP) is now understood as a complex phenomenon involving cortical reorganization (adjacent cortical areas expanding into the deafferented representation zone), peripheral sensitization from neuromas, and central sensitization in spinal dorsal horn and brain. Neuromas contribute to triggering sensations but the cortical maladaptive reorganization is the primary driver of persistent pain — patients with larger cortical reorganization have more severe PLP. Treatment includes mirror therapy (aims to reverse cortical reorganization), graded motor imagery, and medications (gabapentin, amitriptyline, ketamine).

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.