Steven C. Stewart

One hundred consecutive laparoscopic pelvic lymph node dissections: Comparing complications of the first 50 cases to the second 50 cases

OBJECTIVES To report the outcome of our first 100 consecutive laparoscopic pelvic lymph node dissections (LPLND) and compare the early complication rate of the first 50 cases (14%) to the second 50 cases (4%). METHODS We reviewed 100 patients who underwent LPLND: Ninety-six patients had carcinoma of the prostate and underwent LPLND prior to radical prostatectomy or definitive radiation therapy. Four patients had histologically proved penile (2) or bladder carcinoma (2) and underwent LPLND to assess their pelvic lymph nodes. RESULTS We encountered 7 major and minor complications in our first 50 cases, and 2 minor complications in our second 50 cases. The overall complication rate was 9% (9 of 100). CONCLUSIONS We believe that modification of our operative technique and changes in patient management resulted in a lower complication rate in the second 50 patients. We conclude that although LPLND has a significant learning curve, it is a viable surgical staging option for patients with urologic pelvic malignancies.

Sutureless vasovasostomy: New technique using experimental microclip in rat model

Standard microscopic suture vasovasostomy represents a challenge to many urologists. It is technically demanding, and requires two to five hours of operative time. In an attempt to decrease the technical demand and the time requirement, we report the use of a microvascular anastomotic clip and compare this microclip to a standard eight-suture nonstented technique and a six-suture stented technique using a hollow, absorbable 0.5-mm polyglycolic acid stent. The control group with suture required an average of 38.5 minutes per anastomosis for the nonstented group and twenty-two minutes for the stented group. The clip group required 7.6 minutes for the unstented vasovasostomy and 6.5 minutes for the stented vasovasostomy. We obtained a 91 percent patency rate for the stented clip group and 100 percent patency for the unstented clip group. In a rat vasovasostomy, the operative time as well as the inherent technical demand were significantly reduced.

Effect of the calcium entry blocker verapamil on renal ischemia

The ability of the calcium entry blocker verapamil to ameliorate the effects of renal ischemia was studied in ten sheep. Postanesthesia, bilateral cutaneous ureterostomies were placed in each sheep to facilitate urine collection and analysis. Both kidneys were made ischemic for one hour by occluding each renal artery. However, immediately before occlusion of the right renal artery, 0.05 mg/kg of verapamil was injected into the artery. Comparison of urinary creatinine excretion and urine volume for 72 h after reversal of ischemia demonstrated that those kidneys pretreated with verapamil had greater functional preservation (p less than .05). In this study, verapamil appeared to provide protection against renal damage after an ischemic insult.

Renal preservation following severe ischemia and prophylactic calcium channel blockade.

The ability of the calcium channel blocker verapamil to prevent renal ischemic damage was assessed in a randomized double blind study of 41 rats. Study animals received either intravenous verapamil or placebo prior to renal pedicle occlusion and contralateral nephrectomy. Rats receiving verapamil pretreatment demonstrated significantly greater functional preservation 48 hours after ischemia (p less than 0.005) and exhibited better overall survival rates. In this study verapamil provided protection against renal damage following ischemia.

Histopathologic Evaluation of the Canine Prostate Following Electrovaporization

PURPOSE Transurethral electrovaporization of the prostate (TVP) for symptomatic benign prostatic hypertrophy (BPH) has proven to be efficacious with minimal patient morbidity. When compared to transurethral resection of the prostate (TURP), TVP demonstrates comparable postoperative flow rates, American Urologic Association (AUA) symptom score indices, and a potential cost savings. However, in the human studies it has not been possible to correlate these clinical parameters with procedure-related histopathologic changes in the prostate immediately postoperative or during wound healing. The following study was done using a canine model in an effort to evaluate these histopathologic changes. METHODS AND MATERIALS Fifteen hounds (25-35 kg.) underwent antegrade electrovaporization of the prostate, via an open cystotomy, using a Circon ACMI USA series resectoscope and video equipment. The dogs were sacrificed and the prostates harvested at various intervals postoperatively (0-11 weeks). The prostates were evaluated grossly as well as histologically for cavitary defects, depth of necrosis, and cellular response. RESULTS Prostates examined immediately following the procedure demonstrated superficial necrosis (less than 2 mm.) in the region of vaporized tissue. One week postoperatively, the vaporized regions demonstrated an intense acute inflammation amidst superficial necrosis with focal hemorrhage and dystrophic calcification. Transient glandular cystic changes developed, but were resolving by seven weeks postoperatively. Re-epithelialization was underway by the third postoperative week and epithelial stratification underway by the fifth week. There was no extension of the initial two millimeter zone of necrosis at any time point examined. CONCLUSION TVP in the canine model vaporizes prostatic tissue at the site of contact. Only a shallow remnant of necrosis remains at the site of vaporization, indicating the highly localized effect of this technique. Healing at the site of vaporization occurs in a rapid and expected manner. These data provide a histopathologic rationale for the minimal morbidity and the efficacious nature of this technique demonstrated in clinical studies.

Use of a subcutaneous tunnel following replantation of an amputated penis

We describe a new technique for immobilization and protection of the penis following microsurgical replantation, using a subcutaneous tunnel created in the suprapubic area. This tunnel protects the phallus from reinjury while maintaining an anatomic position and a normothermic environment in the immediate postoperative period.

Urological applications of the holmium laser

While the role of endoscopy was initially diagnostic, the advent of improved endoscopes and working instruments have increased its therapeutic applications. One of the most recent advances is the holmium laser. It has a broad range of urological applications due to its ability to fragment all urinary calculi and its soft tissue effects. This laser is based on laser energy delivered in a pulsatile fashion at 2100 nm. The purpose of this study is to report our experience with the holmium laser. A retrospective study of patients undergoing endourological procedures with the holmium laser was performed. One hundred and forty patients underwent 157 procedures. The holmium laser was used for the treatment of urinary calculi in 122 patients. Stone location included 61 renal, 64 ureteral, and 17 bladder stones. Renal stone burden was 17 mm (range 3-50), ureteral stone size averaged 10 mm (range 3 - 35), and mean bladder stone size was 31 mm (range 10 - 60). Other uses included treatment of transitional cell carcinoma of the renal pelvis, ureter, and bladder, incision of ureteral strictures, ureterocele, and prostate, and ablation of renal hemangiomas. Intraoperative and post operative complications were noted. Follow-up for calculi consisted of a plain film of the abdomen at one week and an ultrasound or intravenous pyelogram at six to eight weeks post procedure. No ureteral perforations or strictures occurred. The Holmium laser was capable of fragmenting all urinary calculi in this study. No complications were directly attributable to the Holmium laser. In our initial experience, the Holmium laser is safe and effective in the treatment of urinary pathology. It is the most effective lithotrite available and is able to incise and coagulate soft tissue as well. This combination allows the urologist to treat a variety of urinary pathology using a single modality. Its main limitation is the ability to access lower pole lesions in the upper urinary tract due to the fibers stiffness. Use of laser fibers larger than 200 microns occasionally limit deflection into a lower pole or dependent calyx.

Effect of calcium entry blocker nitrendipine on renal function after renal vascular occlusion

The ability of the Ca entry blocker nitrendipine to improve postischemic renal function was studied in nine groups (n = 70) of rats. After anesthesia, nitrendipine was administered for 15 min through the femoral vein. The dose administered depended on the group. Group 1 (n = 7), the control, received only 0.9% NaCl, group 2 (n = 12) 0.25 mg/kg; group 3 (n = 10) 0.50 mg/kg; group 4 (n = 8) 0.75 mg/kg; group 5 (n = 6) 1.00 mg/kg; group 6 (n = 7) 1.50 mg/kg; group 7 (n = 7) 2.00 mg/kg; group 8 (n = 6) 2.50 mg/kg; and group 9 (n = 7) 3.00 mg/kg. After the administration of nitrendipine, the kidneys were rendered ischemic for one hour by cross-clamping the renal vessels. Comparison of 24-h creatinine clearances for 72 h after reversal of ischemia demonstrated that nitrendipine was capable of providing a degree of protection against renal ischemia and the protective effect was dose dependent (p less than .05).

Holmium laser lithotripsy of urinary calculi: initial experience with the 200-μm holmium laser fiber

We performed a pilot evaluation of the 200 micron holmium laser fiber to treat a variety of ureteral and renal calculi. The 200 micron laser fiber has the potential advantage of being more malleable and therefore having increased deflectability compared to larger laser fibers. A total of sixty patients underwent treatment for urinary calculi either primarily or as an adjunct. Thirty-three intrarenal stones and 26 ureteral stones were ureteroscopically treated with the 200 micron holmium laser fiber. Mean stone burden was 12.8 mm for renal stones (range equals 3 - 40 mm) and 7.7 mm for ureteral stones (range 5 - 15 mm). The ability to treat calculi in dependent calices and energy required to fragment calculi were studied. In addition, a bench top study was performed to determine the effect of the 200 micron fiber on active deflection of various flexible ureteroscopes. The bench studies revealed that the 200 micron fiber limited the flexibility of the ureteroscopes from 9 to 43 degrees depending on the ureteroscope. In spite of the limitation demonstrated in the bench top studies, in vivo we found that using the small diameter laser fiber, we could access and treat calculi located within dependent and lower pole calices. In addition, although the 200 micron fiber did inhibit deflection of flexible ureteroscopes, in all cases we were able to obtain access to the lower pole using this fiber.

Early complications with the holmium laser

The purpose of this study is to report early complications in our initial experience with the holmium laser in 133 patients. A retrospective study of patients undergoing endourological procedures with the holmium laser was performed. Complications included urinary tract infection (3), post-operative bradycardia (1), inverted T-waves (1), intractable flank pain (1), urinary retention (1), inability to access a lower pole calyx with a 365 micron fiber (9), stone migration (5), termination of procedure due to poor visualization (2). No ureteral perforations or strictures occurred. The holmium laser was capable of fragmenting all urinary calculi in this study. In our initial experience, the holmium laser is safe and effective in the treatment of genitourinary pathology. Use of laser fibers larger than 200 microns occasionally limit deflection into a lower pole or dependent calyx.