The Effect of Traction Force and Hip Abduction Angle on Pudendal Nerve Compression in Hip Arthroscopy: A Cadaveric Model

Abstract

To investigate the site of pudendal nerve compression and the relation between traction force and abduction angle regarding pressure levels at setup for hip arthroscopy. A total of 17 hips from 9 fresh-frozen cadavers (6 male and 3 female cadavers) were used. The pudendal nerves were dissected, and 3 FlexiForce force sensors (Tekscan, Boston, MA) were implanted on the pudendal nerve where the inferior rectal nerve, perineal nerve, and dorsal nerve of the clitoris/penis emerge. A custom-made traction table in a supine position was used with a padded perineal post of 9cm. Recordings were made at 0, 10, 20, 30, and 40kg of traction at varying hip abduction angles of 0°, 15°, 30°, and 45°. The tuber ischiadicum (perineal nerve) and genital region (dorsal nerve of penis/clitoris) had statistically higher pressure values when compared with the pudendal canal (inferior rectal nerve) (P < .05). There was a significant increase in forces acting on the pudendal nerve with increasing application of 0 to 40kg of traction in steps of 10kg, with the exception of the pudendal canal sensor and reading of the perineal nerve sensor at 45° of hip abduction (P < .004 with Bonferroni correction for significant values). On the contrary, hip abduction angle had no statistically significant effect on pudendal nerve compression. (All specific P values with Bonferroni correction were greater than .003.) To avoid nerve palsy completely, the etiopathogenesis of compressive neuropathy should be identified. The location for compression and relation between different traction positions and forces are clarified in this study. This information can be used for further research and prevention. This study adds objective data on the etiopathogenesis of pudendal nerve compression, which potentially contributes to prevention of pudendal nerve palsy as a common complication of hip arthroscopy.