Laser coagulation prostatectomy: evolution of clinical practice and treatment parameters

In-hospital mortality after transurethral resection of the prostate in Victorian public hospitals

BACKGROUND

The purpose of the present paper was (i) to identify trends in in-hospital mortality after transurethral resection of the prostate (TURP) in Victorian public hospitals; and (ii) to explore associations between in-hospital mortality after TURP and age, adverse events, type of admission (emergency/planned), location of the hospital (metropolitan/rural), teaching status of the hospital and length of stay.

METHODS

Trends in in-hospital mortality after TURP and the associations between in-hospital mortality and the aforementioned variables were studied using International Classification of Diseases, 9th revision, Clinical Modification (ICD-9-CM) coded Victorian hospital morbidity data from public hospitals between 1987-88 and 1994-95. Crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) were based on univariate and multivariate logistic regression, respectively.

RESULTS

After adjustment for age, comorbidity, and other confounding variables, the trend in mortality reduction over time was highly significant (P for trend < 0.0001, 95% CI for trend: 0.84-0.95). Highly significant associations with mortality were observed for emergency admissions (OR = 1.99, P < 0.0001), presence of adverse events (OR = 2.69, P < 0.0001), length of hospital stay (P for trend < 0.0001, 95% for trend: 1.88-2.15) and age (P for trend < 0.0001; 95% CI for trend: 1.26-1.48).

CONCLUSIONS

Routinely collected data from hospitals can provide tentative evidence of improved effectiveness of a surgical treatment, provided analysis takes careful account of potential sources of bias, especially those related to possible changes in case selection over time. These kinds of data should stimulate a joint effort between clinicians, quality assurance experts and epidemiologists to confirm this attribution, and to locate the causative factors.

The "Wedge" resection device for electrosurgical transurethral prostatectomy

The "Wedge" (Microvasive, Natick MA) is a new electroresection device for transurethral prostatectomy (TURP) using the standard resectoscope. The design, which is broader than the standard loop and thickens from front to back, results in better hemostasis when used at 275 to 300 W because of its ability to cut and coagulate tissue simultaneously. In the canine model, histologic examination demonstrated a 2-mm zone of coagulation around the chips and in the resection bed; this response was not observed in the specimens resected by the standard tungsten loop. No adjacent tissue damage was found with either the Wedge or the loop, and the temperatures recorded at the capsule rose only 4 degrees C regardless of the device used. In the 65 patients treated, the average hematocrit drop on postoperative Day 1 was 3.0%, and serum sodium was unchanged. One year postoperatively, the peak flow rate had increased by 101%, and the AUA Symptom Score was 6.1. The only surgical complication was urethral strictures (3%) necessitating incision. Most striking was the increased case of resection attributable to improved intraoperative vision. The data suggest that Wedge TURP is as safe and efficacious as standard loop TURP. The surgical field is markedly improved and clear because of intraoperative hemostasis. A TURP can be performed with a view toward minimizing patient morbidity and increasing surgical ease.

Visual laser ablation of the prostate (VLAP) with bare fiber in conjunction with laser bladder neck incision in the treatment of patients with benign prostatic hyperplasia (BPH)

The objective of this paper was to assess the effectiveness of visual laser ablation of the prostate (VLAP) using a bare fiber with simultaneous laser incision of the bladder neck for patients with symptomatic benign prostatic hyperplasia. Sixty-seven patients with symptomatic bladder outlet obstruction due to benign prostatic hyperplasia were entered into a prospective trial where VLAP was done with neodymium:YAG laser, while the bladder neck incision was done with KTP laser. The laser was delivered using a bare fiber. There was marked improvement demonstrated at three months post-lasing in symptom score and flow rate. No significant changes were noticed in the subsequent follow-up. However, the addition of the bladder neck incision increased the rate of retrograde ejaculation without appreciable improvement in symptom score or flow rate when compared to other published data. None of the patients developed bladder neck contracture. VLAP, using a bare fiber, in conjunction with laser bladder neck incision, produces durable improvement in urine flow rate and symptom score in patients with symptomatic benign prostatic hyperplasia without the development of bladder neck contracture. This method will reduce the costs of laser prostatectomy.

Visual laser coagulation of the prostate using intraurethral gel anesthesia and light intravenous analgesia and sedation

Twenty-eight patients with symptomatic bladder outlet obstruction secondary to benign prostatic hyperplasia were treated as outpatients by visual laser coagulation of the prostate using only intraurethral gel anesthesia and light intravenous sedation and analgesia. No premedication was administered. Laser coagulation was performed with the Myriadlase side-firing fiber using a standard Sharplan neodymium: YAG laser source at 40 W power setting, and 650 (516-1000) J/g of prostate tissue was delivered. Patient acceptance was favorable. All remained relaxed, cooperative, and without pain during the procedure. None of the patients required any further anesthesia. There was no significant change in blood pressure, pulse rate, or peripheral oxygen saturation measurements during the procedure. Any patient who feels comfortable with a diagnostic cystoscopy being performed using intraurethral gel anesthesia should find this anesthesia protocol acceptable for laser coagulation of the prostate.

Optical characterization and coagulation performance of side-emitting fiber delivery systems for laser therapy of benign prostatic hyperplasia: a comparative study

OBJECTIVES

Currently, various side-emitting optical fibers with different tip geometry are used transurethrally to deliver laser radiation for treatment of benign prostatic hyperplasia (BPH). Since fiber tip design could profoundly affect the size and profile of the emitted laser beam, and consequently the tissue response and the extent of tissue coagulation, we evaluted commercially available fibers in regard to their optical characteristics and their ability to coagulate tissue in a controlled experimental setting.

METHODS

Thirteen fibers manufactured by different companies and clinically used at the present time were tested using a surgical neodymium: yttrium-aluminum-garnet laser. The profile of the laser beam delivered via each fiber was imaged on a CCD camera at various distances and evaluated by means of a laser beam analyzer. Beam divergence angle was then calculated for each tip. Tissue coagulation effects were assessed by irradiating samples of beef muscle immersed in water at 37 degrees C. The fiber tip was kept 2.5 mm away from the tissue and irrigation was maintained at flow rate of 350 to 400 cc/min during irradation. Laser powers of 20, 40, and 60 W were used for 180, 90, and 60 seconds, respectively, delivering a total energy of 3600 J.

RESULTS

The results of the optical evaluation divided the fibers into two major groups: broad beam with large divergence angle and narrow beam with small divergence angle. Statistical analysis of the data (using analysis of variance) showed that volumes of coagulated tissue were significantly larger for broad beam fibers than for narrow beam fibers (1.15 +/- 0.32 versus 0.89 +/- 0.34 cm 3; P < 0.05). Also, significantly larger volumes were obtained for 20 W when compared with 60 W (1.08 +/- 0.43 versus 0.88 +/- 0.27 cm 3; P < 0.05).

CONCLUSIONS

The laser power density delivered by individual fibers to the prostate tissue may vary significantly, thus greatly affecting the extent of tissue coagulation. Therefore, irradiation parameters must be optimized for each fiber type.