Pressure and Nerve Lesion in the Carpal Tunnel

Abstract

In 16 patients, where the diagnosis carpal tunnel syndrome was electrophysiologically confirmed, the pressure between the median nerve and the carpal ligament was measured peroperatively. At rest the pressure was 18-64 mmHg, mean 31 mmHg. Passive volar and dorsal wrist flexion increased the pressure about three times. Isometric or isotonic maximal contractions of wrist and finger muscles, elicited by tetanic nerve stimulation increased the pressure to three to six times the resting value. These high pressures may be one of the causes of the nerve lesion in the carpal tunnel syndrome.

Impact of occupations and job tasks on the prevalence of carpal tunnel syndrome.

“…A localized pressure greater than 50 mm Hg ( =:: 6666 Pa) in the carpal tunnel or a tourniquet with a pressure higher than systolic around the upper arm will cause a conduction block in the median nerve at the wrist (44). Extreme flexingor extension of the wrist causes an increase in pressure in the carpal tunnel that can affect the blood perfusion of the median nerve (49,50). The histopathology of CTS shows coherence with the epidemiologic evidence for physical work load as 344 a risk factor .…”

Pressures recorded in ulnar neuropathy

“…In normal subjects Gelberman et al (1981) observed a pressure of 30 mm Hg in this position. In patients with the carpal tunnel syndrome, a pressure of about 90 mm Hg was observed by both Gelberman et al (1981) and Werner et al (1983). Contractions of the wrist and finger flexor muscles increase the pressure in the carpal tunnel to about 150 mm Hg in patients with a carpal tunnel syndrome (Werner et al 1983).…”

“…To keep the recording system patent the catheter was continuously perfused with heparinized saline (50 WUmin). This pressure recording system is a routine set-up for pressure determinations in experimental situations and has previously been used when investigating the pressure in the carpal tunnel (Werner et al 1983).…”

A conceptual model for work-related neck and upper-limb musculoskeletal disorders.

“…Lundborg et al (73) showed that intracarpal canal pressure can lead to impaired conduction and sensory function of the median nerve in less than 1 h. An increase in carpal tunnel pressure of three to six times the resting value was found during isometric or isotonic maximal contractions of wrist and finger muscles (74). These changes were related to mechanical pressure and perfusion of the median nerve.…”

“…A localized pressure above 50 mm Hg ("'6.65 kPa) in the carpal tunnel or pressure above the systolic level from a tourniquet around the upper arm causes a conduction block in the median nerve at the wrist (73,78). Extreme flexion or extension of the wrist causes an increase of pressure in the carpal tunnel that can affect the blood perfusion of the median nerve (74,87,88).…”