Comparison of carpal canal pressure in paraplegic and nonparaplegic subjects: Clinical implications

The purpose of this study was to evaluate the pressure within the carpal tu nnel that was generated with certain tasks in paraplegic versus nonparapleg ic subjects. Four groups of subjects were evaluated: 10 wrists in six parap legic subjects with carpal tunnel syndrome, 11 wrists in six paraplegics wi thout the syndrome, 12 wrists in nine nonparaplegics with the syndrome, and 17 wrists in 11 nonparaplegics without the syndrome. Carpel canal pressure s were measured in the wrists in three positions (neutral, 45-degree flexio n, 45-degree extension) and during two dynamic tasks [wheelchair propulsion and RAISE (relief of anatomic ischial skin embarrassment) maneuver]. Exter nal force resistors were placed over the carpal canal and correlated with i nterval tunnel pressures. At each wrist position, paraplegics with carpal t unnel syndrome consistently had higher carpal canal pressure than did the o ther groups at the corresponding wrist position; statistical significance w as evident wit h regard to the neutral wrist position (p < 0.05). Within ea ch group of subjects, wrist extension and wrist flexion produced a statisti cally significant increase in carpal canal pressure (p < 0.05), compared wi th the neutral wrist position. Dynamic tasks (wheelchair propulsion and the RAISE maneuver) significantly elevated the carpal canal pressure in parapl egics with carpal tunnel syndrome, compared with the other groups (p < 0.05 ). Lastly, there is a linear positive correlation between carpel canal pres sure and external force resistance.