Laser-assisted demucosalized gastrocystoplasty with autoaugmentation in a canine model.

OBJECTIVES: Laser-assisted autoaugmentation gastrocystoplasty has been performed successfully. Experiments were performed to determine the optimal laser for tissue welding during demucosalized autoaugmentation gastrocystoplasty using both a 1.9-microm diode and a 1.32-microm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser with and without thermal control. METHODS: Autoaugmentation gastrocystoplasty was performed on 18 female mongrel dogs. Anastomoses were performed by either suture or laser welding with a 50% human albumin solution. A 1.9-microm diode laser was compared with a 1.32-microm Nd:YAG laser with and without thermal control. In vivo canine bladder capacity measurements were performed both before gastrocystoplasty and at euthanasia. The animals were studied on days 4 and 14. Samples of the anastomotic area from each group were taken to measure tensile strength. Histologic samples were assessed for tissue damage. RESULTS: There was a significant increase in bladder volume in the 4-day group compared with pregastrocystoplasty values. Both the 1.9-microm diode laser and suture control dogs with the 14-day repairs had significantly more tensile strength than their 4-day counterparts. In contrast, no statistical difference was found between the 4 and 14-day 1.32-microm Nd:YAG groups. The suture control group had evidence of minor tissue devitalization at the anastomosis at both 4 and 14 days. The 1.9 and 1.32-microm laser groups both had evidence of tissue devitalization at 4 and 14 days. The 1.32-microm laser group had primarily severe tissue injury. The laser groups at 14 days demonstrated an inflammatory reaction that was localized to the albumin. CONCLUSIONS: Demucosalized gastrocystoplasty with autoaugmentation can be safely and successfully performed with a 1.9-microm diode laser without significant differences in tensile strength when compared with suture controls. The 1.32-microm Nd:YAG laser can also be successfully used; however, the long-term results appear to be inferior to the 1.9-microm diode laser.

Effects of temperature on tissue thermal injury and wound strength after photothermal wound closure.

BACKGROUND AND OBJECTIVES: Our goal was to determine the effect of temperature on the induction of tissue damage after laser-welded wound closure with and without albumin solder. STUDY DESIGN/MATERIALS AND METHODS: Multiple full-thickness skin incisions were made in a porcine model. Incisions were repaired by using a 1.32-microm laser at temperatures of 65 degrees C, 75 degrees C, 85 degrees C, or 95 degrees C with and without a 50% human albumin solder. The rate of apoptosis (programmed cell death) was quantified by counting the proportion of cells that stained positively for nuclear DNA fragmentation (nick end labeling). The distance that necrosis extended from the wound edge was also measured. The strength of the weld was measured with a tensiometer. RESULTS: For laser-welded repairs with solder, the amount of apoptosis at 65 degrees C and 75 degrees C was comparable to that of controls but became significantly elevated at 85 degrees C and 95 degrees C. The extent of necrosis was similar to that of controls at low temperature but also increased at 95 degrees C. Incisions repaired without solder showed increased necrosis compared with those repaired with solder at temperatures of 65 degrees C, 75 degrees C, and 95 degrees C at 0-0.5 mm from the incision. Wounds repaired at 85 degrees C and 95 degrees C showed more apoptosis in the absence of solder. The increased cell death at higher temperatures correlated with significantly decreased wound strengths at 3 days after repair in the solder group. A lower rate of cell death was observed in the solder group, which correlated with superior wound strength when compared with repairs without solder at days 0 (65-95 degrees C) and 3 (95 degrees C). CONCLUSION: Both apoptotic and necrotic cell death were used as quantitative measures of tissue injury and were accurate predictors of short-term wound strength. The addition of albumin solder decreased overall tissue injury. These results suggest that temperatures of 65-75 degrees C with solder provide the optimal conditions for maximizing acute wound strength and minimizing tissue injury.

Gastrocystoplasty: long-term complications in 22 patients.

PURPOSE: Gastrocystoplasty has been performed as an alternative to enterocystoplasty to increase bladder capacity and/or compliance while avoiding the complications associated with the use of bowel segments. Gastrocystoplasty is not without metabolic and physiological complications, such as the dysuria-hematuria syndrome and hypochloremic metabolic alkalosis. Currently to our knowledge there is limited long-term followup of gastrocystoplasty, which prompted us to review our experience with gastrocystoplasty and compare our findings with those of others. MATERIALS AND METHODS: We retrospectively reviewed for complications the records of 12 boys and 10 girls 8 to 24 years old who underwent gastrocystoplasty. Followup ranged from 48 to 96 months. The diagnosis included neurogenic bladder in 12 cases, posterior urethral valves in 6, bladder exstrophy in 3 and pelvic tumor in 1. All patients underwent preoperative evaluation of serum electrolytes, blood urea nitrogen and creatinine as well as a radionuclide renal scan. Urodynamics were done preoperatively in all patients and postoperatively for complications. A gastric wedge with the pedicle based on the right gastroepiploic artery was removed, leaving the lesser curvature and vagus nerve intact. This technique was used in 21 of the 22 cases, including 1 case after initial surgery elsewhere. Ureteroneocystotomy, Mitrofanoff appendicovesicostomy and bladder neck reconstruction were performed as indicated. RESULTS: There was 1 early complication (postoperative bleeding) and the remainder were late complications, including vesicoureteral reflux in 4 cases, Mitrofanoff valve stenosis in 3, the hematuria-dysuria syndrome, renal calculi, decreased bladder capacity with incontinence and metabolic alkalosis in 2 each, and ureterovesical stricture in 1. The late complication rate in our series was 36%. CONCLUSIONS: Our long-term results differ from those of others in the number of late complications (36 versus 21.8%). In addition, 50% of our patients with complications had multiple complications. These findings may be due to a longer followup. Nevertheless, our data cast serious doubt on the long-term advantages of using stomach for bladder augmentation.