Carpal canal pressure measurements: Literature review and clinical implications

Abstract

The first evaluative reviews regarding the use of a measurement system for determining carpal tunnel pressure was introduced by Brian et al. 1947 [1]. The second evaluative review appread in the medical literature 10 years later and was published by Tanzer [2]. Sophisticated and nondangerous instrumentation was not available at that time in order to measure actual carpal tunnel pressure in live subjects. Both auhtors used rudimentary methods (Foley no. 14 catheter connected to a manometer) and measured cadavers' carpal tunnel pressure by studying the pressure measurement obtained when the wrist was placed in various postures: flexion and above all axtension. In Brain's studies, wrist extension pressure was three times that obtained in flexion (Table 7.1). These same results were reconfirmed by Tanzer, who further demostrated that the carpal pressure was higher in the more proximal part of the carpal canal, with the wrist flexed, rather than extended, whereas, the pressure was higher in the sistal part of the canal only when the wrist was extended. Based on anatomo-surgical landmark, where the median nerve widens immediately proximally to proximal carpal canal margins, both Brain and Tanzer concluded that the wrist produces more abnormal symptoms when flexed in respect to when it is extended, even if the experimental studies have demonstrated that an increse in carpal pressure occurs in wrist extension © 2007 Springer-Verlag Berlin Heidelberg.