Gracilis muscle neosphincter for treating urinary incontinence.

The purpose of this study was to test the anatomical and functional feasibility of using a gracilis muscle free flap to create a urinary sphincter. Anatomical studies were performed in 12 human cadavers and short-term (n = 7) and long-term (n = 8) functional studies were performed in dogs. In the short-term functional studies, the left gracilis muscle was transferred into the pelvis and wrapped around the urethra and the right gracilis muscle was wrapped around a stent. A cuff electrode was placed on the muscle's nerve pedicle and used to stimulate the neosphincter while peak pressure, fatigue rate, and perfusion measurements were performed. In the long-term functional studies, intramuscular electrodes were inserted into the neosphincter to stimulate the flap. The flaps were wrapped around the urethra and dogs were followed for 16 weeks, during which time urodynamic measurements were performed. Our anatomical studies demonstrated that the gracilis muscle free flap could be transferred into the pelvis to create a urinary neosphincter. Our short-term functional study demonstrated that gracilis muscle free-flap function and perfusion were not compromised by transfer. In our long-term functional study, all neosphincters provided bladder outlet resistance pressures consistent with continence. Our anatomical, short-term, and long-term functional studies indicate that a gracilis muscle free-flap neosphincter is an effective procedure for treating urinary incontinence.

Muscular urinary sphincter: electrically stimulated myoplasty for functional sphincter reconstruction.

PURPOSE: To reconstruct an electrically stimulated muscular urinary sphincter (MUS) using a tailored gracilis muscle free flap with intact nerve. MATERIALS AND METHODS: Unilateral surgically tailored gracilis muscle free flaps were transferred into the pelvis in eight dogs, leaving the obturator nerve intact. The muscle's pedicle vessels were anastomosed to the inferior epigastric artery and vein in the pelvis and the muscle was wrapped around the bladder neck. Electrodes were inserted into the MUS and connected to a programmable pulse generator. After 8 weeks of training the MUS, the pulse generator was programmed to be "on" for 4 hours and "off' for 15 minutes in a continuous cycle. Urodynamic studies were performed periodically, and at the end of the experiment the MUS and proximal urethra were harvested for histology. Three control dogs had sham operations. RESULTS: All MUS's functioned well following the procedure. Histology of the MUS/urethra complex showed no evidence of stricture. Except for one dog, all urethras were easily catheterized. CONCLUSIONS: This electrically stimulated innervated free-flap MUS technique effectively increases bladder outlet resistance without producing urethral obstruction.

Electrically stimulated free-flap graciloplasty for urinary sphincter reconstruction: a new surgical procedure.

In electrically stimulated (dynamic) graciloplasty for urinary incontinence, the gracilis muscle is transposed into the pelvis, and the distal part is used to reconstruct a neosphincter. Clinical outcomes using this technique have been disappointing due to stricture of the urethra caused by ischemia in the distal part of the gracilis and limited gracilis length available for neosphincter construction. Furthermore, the urethra is twisted by the contracting gracilis, rather than circumferentially squeezed. The purpose of the present study was to test the anatomical and functional feasibility of a new surgical approach to reconstruct a urinary sphincter, using the gracilis muscle as a free flap. In 12 human cadavers, the anatomical feasibility for creating a neosphincter by using the gracilis free flap was determined. In all cases, transfer of the gracilis muscle into the pelvis as a free flap (with the nerve intact) was feasible, and ample muscle was available to construct a neosphincter around the bladder neck. Gracilis neosphincter function was studied in seven dogs. The left gracilis muscle was subjected to transfer into the pelvis as an innervated free flap to create a neosphincter around the urethra. The right (control) gracilis muscle was lifted as a single pedicle flap, remained in situ, and was wrapped around a stent to mimic the urethra. Function (expressed as peak pressure generation and fatigue rate) and surface perfusion were determined for all gracilis muscles. In each dog, both sides were compared using the paired Student's t test for statistical analysis, and no significant difference was measured for the two groups. In conclusion, an innervated gracilis free flap can be used to create a neosphincter around the bladder neck. In an acute study in dogs, function and perfusion of the innervated gracilis free flap are not compromised.

Vascular delay in skeletal muscle: a model for microcirculatory studies.

Dynamic myoplasty is a relatively new use for muscle flaps and has led us to revisit the mechanisms of vascular delay as a means of optimizing blood supply to muscle flaps. Despite the well-documented effectiveness of vascular delay in skin flaps, vascular delay in muscle flaps has not been widely reported. Regardless of the many mechanisms postulated in the literature as contributors to the delay effect in skin, the one element common to all these hypotheses is the importance placed on changes in the microcirculation. Based on this factor, in the present study we developed and validated an animal model in which delay-induced microvascular changes could be measured in skeletal muscle flaps. We used the hairless mouse latissimus dorsi muscle flap because its vascular distribution is similar to that of humans and its thin structure will enable us in future studies to directly view and measure its microvasculature using videomicroscopy. In 12 animals, we found that delay significantly (p < 0.01) reduced necrosis of the distal part of the muscle from 57 +/- 9 percent in nondelayed flaps (n = 7) to 22 +/- 3 percent in delayed (n = 5) flaps. In these studies, we also determined that the hairless mouse latissimus dorsi muscle flap will serve as an excellent model for defining microvascular changes throughout delay.

Brain metastases from an unknown primary tumour: which diagnostic procedures are indicated?

Seventy two patients presenting with symptomatic brain metastases from undiagnosed primary neoplasms were retrospectively reviewed. Primary malignancies were diagnosed before death in 54 patients and remained unknown in 18 patients. Lung cancer was the most common primary tumour (72%), followed by breast cancer, colon carcinoma, and melanoma. On physical examination, 51 patients had organ specific symptoms or signs providing guidelines to the diagnostic evaluation. In 24 of the 52 patients with a primary lung tumour, and in four of the 20 patients without, organ specific complaints or findings suggested this tumour type, resulting in a positive predictive value of 85%. Overall, radiography and CT of the chest were very useful in detection of primary lung tumours. This could partly be explained by the high prior probability of detecting such tumours. Other diagnostic procedures should be used on indication only. The prognosis of patients with confirmed primary tumour position did not differ from those with unidentified primary tumour.