Acute median neuropathy after wrist trauma. The role of emergent carpal tunnel release.

Ten cases of acute carpal tunnel syndrome (ACTS) and six cases of nerve contusion were identified in patients with acute median neuropathy associated with blunt wrist trauma. The patients with ACTS initially had normal sensation and subsequently developed objective sensory loss (2-point discrimination greater than 15 mm) in the median nerve distribution associated with severe wrist pain. Patients with nerve contusion injuries had immediate sensory loss and symptoms were nonprogressive. Wick catheter measurements of the carpal canal pressure were used in seven patients to help distinguish ACTS (pressure greater than 40 mm Hg) from nerve contusion. The interstitial carpal tunnel pressure was elevated an average of 52 mm Hg in four of five patients with ACTS but was normal in two patients with nerve contusion. Four of five patients who underwent carpal tunnel release within 40 hours of the onset of numbness had normal 2-point discrimination within 96 hours. The results of this study and review of the literature reflect the urgency of carpal tunnel release in ACTS. Neuropathy, secondary to nerve contusion without coexisting ACTS, may be treated initially by observation. Acute carpal tunnel syndrome must be distinguished from nerve contusion as a cause of acute posttraumatic median neuropathy.