Surface localization of sacral foramina for neuromodulation of bladder function. An anatomical study.

A method is described for percutaneous localization of the sacral foramina, for neuromodulation of bladder function. We carried out an anatomical study of 5 male and 5 female human cadaver pelves. Using the described surface markings, needles were placed percutaneously into all sacral foramina from nine different angles. Paths of needle entry were studied by subsequent dissection. We observed that although it was possible to enter any sacral foramen at a wide range of insertion angles, the incidence of nerve root/vascular penetration increased with increasing angle of needle entry. Also, the incidence of nerve root penetration was higher with the medial approach compared with lateral entry. The insertion of a needle into the S1 foramen was associated with a higher incidence of nerve root penetration and presents a potential for arterial haemorrhage. On the other hand the smaller S3 and S4 nerve roots were surrounded by venous plexuses, presenting a potential source of venous haemorrhage during procedures. Our study suggests a new method for identifying the surface markings of sacral foramina and it describes the paths of inserted needles into the respective foramina. In addition, it has highlighted some potential risk factors secondary to needle insertion.

The long head of the biceps femoris: anatomic basis for its possible use in the construction of an electrically stimulated neoanal sphincter.

Electrical stimulation of the nerve to the gracilis muscle following its transposition around the anal canal creates an artificial sphincter capable of actively opposing intrarectal pressure. Not all patients have an available or suitable gracilis. This paper describes the anatomic basis for the use of the long head of the biceps femoris as a potential electrically stimulated neoanal sphincter. The muscle was found to have an adequate length and a suitable arc of rotation for transposition around the anal canal. In 75 percent of thighs studied the neurovascular anatomy of the long head of the biceps femoris was compatible with its utilization in this manner as an alternative to the gracilis.

The inferiorly based masseter muscle flap: anatomical basis for its use in head and neck reconstructive surgery.

The aim of this study was to investigate and elucidate the anatomical basis for the use of the inferiorly based masseter muscle flap in the reconstruction of oropharyngeal defects after ablative surgery. The anatomy of the masseter muscle, with particular emphasis on its blood supply, was studied using plain and coloured resin injected dissections and a series of digital subtraction angiograms and external carotid arteriograms. Both techniques were demonstrated to be reliable and effective means of anatomical investigation of blood vessels. The vascular anatomy of the masseter muscle and the anatomical and angiological results as well as a case report are described. The masseter muscle, when used as an inferiorly based flap, provides the necessary bulk for reconstruction of moderate size defects in the lateral border of the tongue, posterior floor of the mouth, retromolar trigone, anterior tonsillar pillars and lateral pharyngeal wall. Although the masseter muscle has small dimensions, it offers a reliable method of reconstruction in selected defects without the disadvantages of cosmetic and functional loss.