To assess the incision used for routine primary Carpal Tunnel Decompression (CTD), preferred modes of division of the flexor retinaculum and the accuracy with which the motor branch of the median nerve could be identified.

A simple questionnaire was distributed at an orthopaedic regional meeting, which contained a list of simple questions, and a scale photocopy of the palm of a left hand. The surgeons were asked to indicate upon the hand the incision they would make and their prediction of the location of the motor branch of the Median nerve. The data was feed into a desk top spreadsheet program where it was analysed.

43 complete questionnaires were returned, comprising all grades from SHO to consultants. A great majority used a McDonald’s spatula during their division of the retinaculum, with an equal proportion cutting down onto the McDonald’s spatula as were cutting up from it. The shape of the incision was straight in a majority of cases, though some consultants and SpRs tended towards curved or S-shaped incisions. Length of incision varied, among all grades, from 2cm to 6cm, with Juniors tending towards shorter incisions. With respect to Ulna (Medial) or Radial (Lateral) position of the incision, the tendency was to place the incision Radially. 72% of surgeons located the position of the motor branch within 2cm of the actual position, as predicted by Kaplan’s lines.

The surgeons audited tended towards lateral incisions, and hence potentially placing the palmar cutaneous and the motor branches of the median nerve at greater risk.