Lower esophageal sphincter injection of a biocompatible polymer: accuracy of implantation assessed by esophagectomy.

BACKGROUND: Endoscopic lower esophageal sphincter (LES) implantation of a biocompatible polymer is undergoing clinical trial as an alternative to pharmacologic and laparoscopic treatments for gastroesophageal reflux disease. The safety and efficacy of LES augmentation depend on accurate placement of the implant into the wall of the esophagus. To date, no study has demonstrated the prevalence and location of the intended implant. METHODS: The study group consisted of nine patients with underlying esophageal disease severe enough to warrant esophagectomy. Three or four implants of 1 or 2 cc of Enteryx (a biocompatible ethylene-vinyl alcohol copolymer dissolved in dimethyl sulfoxide with micronized tantalum as a radiopaque marker) were placed at the squamocolumnar junction of each patient via a 4-mm, 23-gauge needle under endoscopic guidance. Fluoroscopy was utilized in all patients to facilitate endoscopic placement. Outcome measures included the prevalence and location of successful implantation into the wall of the esophagus. RESULTS: Thirty of 34 implants (88%) were successfully placed into the wall of the esophagus. The remaining 4 were found lying subserosally or attached to the exterior of the gastroesophageal junction (GEJ). Fluoroscopically, the implants often tended to coalesce, forming arcs or a ring around the GEJ. Histologic examination revealed implantation into the deep submucosa contiguous with the circular muscle and within the muscularis propria in all patients, with implants occasionally extending into the subserosa. There were no untoward reactions identified. CONCLUSIONS: Endoscopically directed implantation of a biocompatible polymer into the esophageal wall can be accomplished with a high degree of accuracy. Injection via a 4-mm needle results in the placement of material along and within the muscular layers of the esophagus.

Endoscopic augmentation of the cardia with a biocompatible injectable polymer (Enteryx) in a porcine model.

BACKGROUND: Endoscopic approaches to restore the gastroesophageal barrier in patients with gastroesophageal reflux disease (GERD) are presently undergoing clinical trial. The aim of the study was to demonstrate the feasibility, durability, safety, and antireflux efficacy following augmentation of the cardia with a biocompatible injectable polymer (Enteryx). METHODS: Augmentation was performed in 12 Yucatan mini-pigs. The cardia was injected circumferentially with 1-1.5 ml of Enteryx at three or four sites. Four groups of three animals each were killed at 2, 6, 12, and 24 weeks following augmentation. Gastrointestinal endoscopy and esophageal manometry were performed preoperatively and postoperatively. Competency was determined as the intragastric pressure (yield pressure) and volume (yield volume) needed during gastric distension with air and water to result in equalization of gastric and esophageal pressure. Comparisons were made with a group of noninjected animals (n = 6). RESULTS: All animals had a normal eating pattern; none showed any evidence of vomiting or regurgitation. The median injection volume was 4 ml (range, 1-8). At autopsy, implants were found in 83% of the animals. Intramuscular placement of the implant was durable, whereas sloughing occurred if the implant was placed submucosally. The mechanical properties of sphincter length and pressure were unaffected by the injection. The median yield pressure of the animals that survived for >6 weeks (21.4 mmHg) was significantly greater (p = 0.049) than the animals that survived for <6 weeks (4.5 mmHg) and greater (p = 0.054) than the control animals (9.1 mmHg), suggesting that the healing process was associated with reduced distensibility of the cardia. CONCLUSIONS: Augmentation of the cardia with an injectable polymer (Enteryx) is simple, safe, and durable. Early studies suggest that alteration in the distensibility and geometry of the gastroesophageal junction may provide antireflux protection.

Transperineal radiofrequency interstitial tumor ablation (RITA) of the prostate.

The purpose of this study was to investigate the safety and feasibility of radiofrequency interstitial tumor ablation (RITA) in localized prostate cancer (PCa) and to assess the predictability of the lesions obtained. In 10 patients with localized PCa (mean age 70.4 years), a total of 21 marker lesions were induced under general (n = 3), spinal (n = 4), or local anesthesia only (n = 3). Radiofrequency energy was delivered transperineally under transrectal ultrasound (TRUS) guidance. Radical prostatectomy was performed in all patients 1-7 days after RITA. The findings of intraoperative TRUS and histologic examination of the specimen were correlated. Lesions 2 x 2 x 2 cm were targeted. Postoperatively, patients were catheterized for an average of 1.8 days (range 1-3). Average lesion diameters defined by coagulative necrosis at histologic examination were 2.20 +/- 0.23 x 2.10 +/- 0.31 x 2.38 +/- 0.14 cm (average volume 5.86 +/- 1.63 cm3). Lesions were well defined and did not extend beyond the prostatic capsule. No complications (e.g., rectal wall injury) were noted. RITA-induced lesions were safe, feasible, technically simple, and resulted in lesions well predictable in size and location. On histologic examination, well-defined areas of coagulative necrosis were documented. No damage to the periprostatic tissue was noted. The procedure can be performed with spinal or local anesthesia only.

Percutaneous transperineal radiofrequency ablation of prostate tumour: safety, feasibility and pathological effects on human prostate cancer.

OBJECTIVE: To evaluate the safety of radiofrequency (RF) energy delivered interstitially in patients with prostate cancer scheduled for radical prostatectomy and to correlate the proposed theoretical lesion size with the pathological findings. PATIENTS AND METHODS: Radiofrequency interstitial tumour ablation (RITA) was performed in 15 patients with localized prostate cancer before radical surgery. RF energy was delivered to the prostate by active needle electrodes (monopolar or bipolar) placed transperineally under transrectal ultrasonography guidance. Needle electrodes were used with different configurations and in some cases were covered by retractable shields to vary the length and circumference of the thermal lesions created. In eight patients, the procedure was performed immediately before radical prostatectomy, in six RITA was performed under spinal anaesthesia 1 week before surgery and in one patient, no surgery was performed but the patient was followed by serial determinations of prostate specific antigen (PSA). At least two lesions were created in each prostate, including both capsule and peripheral zones. NADPH and haematoxylin & eosin (H&E) staining were used to assess the extent of the necrotic lesion in the radical prostatectomy specimen. RESULTS: The mean energy delivered was 10.5 kJ, with central temperatures reaching up to 105 degrees C during 12 min of ablation; rectal temperature remained at < 38 degrees C. There were no complications. Macroscopic examination showed well-demarcated lesions including the prostatic capsule, up to 2.2 x 1.5 x 4.5 cm. With monopolar energy, the observed lesion size was comparable to the predicted 2 x 2 x 2 cm lesion, while with bipolar energy, lesion size was related to interneedle distance and uncovered needle length. Microscopic examination showed clearly delineated lesions both with NADPH (in prostates immediately removed after surgery) and H&E (at 1 week after RITA) staining. The lesion size observed on pathological analysis correlated with the predicted lesion size. In one patient, no residual cancer was found in the specimen. In the patient whose entire prostate was targeted and followed by serial PSA measurements, the latter were undetectable at 3 months of follow-up. CONCLUSION: Transperineally delivered RF energy is capable of safely creating extensive coagulative necrotic lesions in prostate cancer tissue, in a reproducible and controlled manner. The results presented here provide basic information for the potential future application of this form of energy for localized prostate cancer.

Transperineal radiofrequency interstitial tumor ablation of the prostate: correlation of magnetic resonance imaging with histopathologic examination.

OBJECTIVES: Radiofrequency (RF) energy has recently been employed to destroy human tissue in vivo. The purpose of this study was to investigate the safety of this approach in localized carcinoma of the prostate (CaP) and specifically, the predictability of lesions obtained with radiofrequency interstitial tumor ablation (RITA). METHODS: Using RITA, a total of 21 lesions were induced in 10 patients with localized CaP (mean age 70.4 years). RF was delivered transperineally under transrectal ultrasound (TRUS) guidance. All patients underwent endorectal magnetic resonance imaging (MRI) before and after treatment. Radical prostatectomy was performed in all patients 1 to 7 days after RITA. Three of the patients were treated with local anesthesia only. The predictability of the thermal lesion was assessed by correlating the findings of intraoperative TRUS, pre- and post-RITA endorectal MRI, and the histologic examination of the specimen. RESULTS: Postoperatively, patients were catheterized for an average of 1.8 days (1 to 3 days). Lesions of 2 x 2 x 2 cm were targeted. Average lesion diameters obtained on MRI were 2.08 +/- 0.23 x 2.09 +/- 0.36 x 2.28 +/- 0.21 cm. Average lesion diameters defined by coagulative necrosis at histologic examination were 2.20 +/- 0.23 x 2.10 +/- 0.31 x 2.38 +/- 0.14 cm. There were no statistically significant differences (P = 0.377) between average lesion volume on MRI (5.37 +/- 1.83 cm3) and average lesion volume at histology (5.86 +/- 1.63 cm3). No complications or adverse events were noted. CONCLUSIONS: In this Phase I study, RITA was shown to be safe and feasible, and to result in lesions that were predictable in size and location. MRI accurately visualized and verified the area of coagulative necrosis as documented at histology. The procedure is technically simple and can even be performed under local anesthesia.

Percutaneous RF interstitial thermal ablation in the treatment of hepatic cancer.

OBJECTIVE: The aim of this study was to evaluate the usefulness of RF interstitial thermal ablation for treating hepatic cancer. SUBJECTS AND METHODS: Fifty patients, 39 who had 41 hepatocellular carcinoma nodules and 11 who had 13 hepatic metastatic nodules, underwent RF interstitial thermal ablation. In all but one, a thermal necrosis volume greater than the tumoral nodule volume was created to obtain total tumor destruction. One large tumor was treated for debulking purposes. RESULTS: Hepatocellular carcinoma nodule destruction was achieved in a mean of 3.3 sessions of RF interstitial thermal ablation. During a mean follow-up of 22.6 months (range, 3-66 months), 16 (41%) of 39 patients had recurrences; two (5%) of these patients showed local recurrences and the remaining 14 (36%) had new lesions. Nine of these 16 patients underwent further RF interstitial thermal ablation that proved effective. RF interstitial thermal ablation was also successfully repeated in four patients who had a second recurrence. With RF interstitial thermal ablation, we treated 54 hepatocellular carcinoma nodules in 39 patients. Eleven (28%) of the 39 patients died: five from hepatic failure due to advanced cancer and six from causes other than cancer. Autopsy was performed on three patients who died from causes other than cancer, one had had two new courses of RF interstitial thermal ablation for two new lesions. Gross examination failed to detect two treated tumor nodules; histologic examination of three other treated tumor nodules showed total necrosis in two nodules and a 3-mm focus of viable cancer cells in the other nodule. Cumulative survival curves showed the median survival time to be 44 months. The survival rate for the first year was 0.94, 0.86 for the second year, 0.68 for the third year, and 0.40 for the fourth and fifth years. In the patients treated for metastatic nodules, posttreatment imaging studies showed necrosis that varied from 80% to 100% in all cases. Pathologic studies performed on two patients who underwent surgery after RF interstitial thermal ablation showed 100% necrosis in one case and 80% necrosis in the other. CONCLUSION: RF interstitial thermal ablation is a useful percutaneous treatment for hepatic cancer.

Isometric detrusor pressure during bladder filling and its dependency on bladder volume and interruption to flow in control subjects.

We characterized the isometric pressures generated by the bladder during voluntary detrusor contraction and interruption of flow. Urodynamic studies were done in 34 healthy female volunteers, with a mean age of 29.6 plus or minus 9.3 years. Control urodynamics were done first to characterize bladder and urethral parameters to filling and voiding. Subsequently, isometric detrusor pressures were elicited during bladder filling at increments of 100 ml. by asking subjects to attempt to void against a urethral obstruction produced by an inflated Foley balloon. Isometric pressures also were obtained by interruption of flow through the lumen of the 22F Foley catheter. The results showed that the maximum isometric pressure increase generated remained relatively constant during bladder filling at 39.6 plus or minus 13.1 cm. water. This pressure is not significantly different from voiding pressures developed with a 10F urethral catheter. On the other hand, isometric pressure increases during voiding showed that the increase in bladder pressure following interruption of flow was volume sensitive. The possibility that this volume dependency may result in errors in the interpretation of bladder contractility is discussed.

Management of infection stones: the Stanford experience.

In summary, 46 renal lithotomies were performed in 40 patients for struvite infection stones. All patients had documented urinary tract infections at the time of surgery; all stones were cultured, demonstrated to contain bacteria and proved crystallographically to be composed primarily of struvite with smaller amounts of apatite. The recurrence rate in a mean followup period of 7 years was 2.5% (one patient). The negligible recurrence rate emphasizes that struvite stones are caused by urea-splitting bacteria, rather than metabolic disorders, and that a comprehensive approach that emphasizes biochemical, bacteriologic, and roentgenographic techniques is more important than the type of surgical procedure used to remove the stones. We believe that our routine of leaving a small polyethylene nephrostomy tube in every patient, combined with postoperative plain-film tomograms regardless of the results of intraoperative radiography, and the liberal use of hemiacidrin irrigation to dissolve any residual struvite particles with their entrapped bacteria, accounts for the virtual absence of stone recurrences in our series.