Management of Nonpainful Supernumerary Phantom Limbs after Incomplete Spinal Cord Injury with Visual–tactile Feedback Therapy: a Case Report

Supernumerary phantom limb (SPL) is an uncommon phantom sensation where the patient experiences the illusory presence of one or more limbs in addition to their existing limbs. SPL after a spinal cord injury (SCI) is rare with few documented cases. There is minimal treatment guidance available, with some reports of visual–tactile feedback therapy used to manage SPL. A 43-year-old male sustained a C4 ASIA Impairment Scale grade C SCI, developing the sensation of two SPL arms originating from his shoulders 6 days after injury. He developed a self-directed method of visual–tactile feedback as a means to improve the SPL sensations, consisting of shrugging his shoulders repeatedly for 1 min while observing the movement of his actual arms. After completion of this routine, the SPL moved to the same location as his arms, providing relief. Also, an elastic band was placed on a sensate region of his arm, providing additional visual–tactile feedback. The SPL improved and resolved by day 45. SPL after SCI is poorly characterized, usually occurring within 6–7 days of injury after a complete or incomplete cervical SCI. While the mechanism is unclear, the inability to integrate visual, tactile, and proprioceptive information after deafferentation may contribute to development. Similarities between SPL and phantom limb sensation after an amputation have resulted in the use of visual and visual–tactile feedback therapy for painful SPL management. This is the first case documenting successful use of visual–tactile feedback therapy to manage nonpainful SPL.