Carpal Tunnel

Clinical case and images provided by Avneesh Chhabra, M.D., Johns Hopkins University School of Medicine, Baltimore, USA

Clinical question

68-year-old man presented with weakness of the hand.

  • Prior history of cervical myelopathy and carpal tunnel release three years ago
  • Mild positive Tinel's sign over the carpal tunnel
  • Phalen test negative
  • EMG study shows combination of findings: radiculopathy,
    symmetric sensory-motor length-dependent peripheral neuropathy,
    severe median neuropathy with sensory motor loss
  • MR Neurography was ordered for further evaluation

Clinical images

Interpretation

  • Inadequate release of flexor retinaculum
  • Bifid median nerve in the carpal tunnel with a persistent, median artery. Mild hyperintensity of the nerve bundles, beginning at the proximal flexor retinaculum, extending into the proximal branches with moderate hyperintensity distally. Minimal flattening of the nerves in the proximal carpal tunnel. Prominent fascicles in the ulnar and radial bundles in the proximal palm
  • Distally, a palmar neuroma in the ulnar sided division of the nerve measuring 10 x 6 x 6 mm at the level of the proximal metacarpal diaphysis of the middle finger
  • Coronal fs PD, PSIF and DTI (not shown) show the neuroma in continuity

Consequences for treatment

  • Repeat flexor retinaculum release needed. Consequently, it was performed resulting in decrease in patient symptoms
  • MRN is important prognostically:
    The neuroma in continuity will not allow complete return of function.