Magnetic resonance imaging after endoscopic carpal tunnel release.

PURPOSE: To determine with magnetic resonance imaging (MRI) the morphologic changes in the carpal tunnel and median nerve 3 months after endoscopic carpal tunnel release (ECTR).

METHODS

We enrolled patients who had complete resolution of numbness and pain by 6 weeks after ECTR. Patients who met these inclusion criteria received an MRI at 3 months after surgery. Images were analyzed to determine whether median nerve morphology changes and discrete gap or separation of the flexor retinaculum could be appreciated on MRI.

RESULTS

There were 17 patients screened and 15 met the inclusion criteria. Three-month MRI in all patients demonstrated changes in the flexor retinaculum over the median nerve. In all 15 patients, a distinct gap or separation in the fibers of the flexor retinaculum overlying the median nerve could not be appreciated. Median nerve width-to-height ratios at the level of the pisiform and at the hook of the hamate were 2.4 and 2.1, respectively. Median nerve cross-sectional area was 14.1 at the pisiform and 13.3 at the hook of the hamate.

CONCLUSIONS

MRI of patients 3 months after successful ECTR does not demonstrate a discrete gap or separation in the flexor retinaculum overlying the median nerve but may be useful for evaluating median nerve morphology.

TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic II.