Extraperitoneal laparoscopic caliceal diverticulectomy.

Three women with symptomatic stone-containing caliceal diverticula in the right kidney were treated by extraperitoneal laparoscopic diverticulectomy. The diverticula measured 31 x 21 mm, 15 x 12 mm, and 12 x 9 mm, with the calculi measuring 10 x 8 mm, 5 x 4 mm, and 6 x 6 mm, respectively. The site of the diverticulum was identified by the presence of a depression on the surface of the kidney. The diverticulum was marsupialized, the lining fulgurated, and in the second and third patients, a flap of Gerota's fascia and perirenal fat inserted. The mean operating time was 127 minutes. The mean postoperative analgesic requirement was six doses of pethidine (meperidine). The median time to drainage tube removal was 3 days, and the median time to discharge after surgery was 4 days. Complications were minimal. On follow-up, all patients were stone free and asymptomatic. The first patient had a slight recurrence of the diverticulum, measuring 15 x 7 mm. Laparoscopic caliceal diverticulectomy has been successful in three patients.

Transurethral Needle Ablation of the prostate (TUNA): clinical results and ultrasound, endoscopic, and histologic findings in pilot study of patients in urinary retention.

Transurethral Needle Ablation of the prostate (TUNA) is a new thermal ablation treatment for benign prostatic hyperplasia (BPH) utilizing radiofrequency electric current delivered by needles into the depth of the prostate to produce an area of coagulative necrosis. A pilot study of 10 patients in urinary retention was undertaken to assess the procedure. After treatment, nine patients voided at a median time of 3 days, although a further two required transurethral resection because of chronic infection in one and chronic urinary retention in the other. At 3 months' follow-up, the mean Qmax was 13.0 mL/sec, the mean AUA Symptom Score was 9.1, and the mean quality of life score was 1.6. The mean Pdet fell from 73.3 to 39.0 cm H2O. On transrectal ultrasound at 3 months, cystic lesions were seen in two patients, with a third having large cavities. A 10.2% reduction in mean prostatic volume, from 48.8 cc to 43.8 cc, was noted but considered to be not significant. On endoscopy at 3 months, mucosal retraction was seen in seven patients, with cavities in two patients. Histologic study in patients undergoing transurethral resection 4 to 6 months after TUNA showed necrosis and fibrosis. It is considered that an area of coagulative necrosis is produced by TUNA that resolves either by scar formation with retraction or by liquefaction with cyst formation. If the lesion communicates with the urethra, a cavity may form, which is undesirable. Our early experience is encouraging. The TUNA treatment is effective, can be given without anesthesia, and should be either a day case or an office procedure. It should prove to have a significant place in the treatment of BPH.

Minimally invasive cancer surgery using focused ultrasound: a pre-clinical, normal tissue study.

Using a focused 1.7 MHz ultrasound field (focal length/transducer diameter ratio of 1.7) and in situ intensities spatially averaged within the half-pressure maximum contour in the range 100-400 W cm-2, ablative lesions have been prescriptively placed singly and in arrays, in the livers and bladder walls of adult female Large White pigs. Exposures were made through the skin with up to 8 cm of intervening tissue. Ablative lesions were placed under ultrasonic guidance, and specific lesion echoes were subsequently observed in two cases. Animals were sacrificed immediately after induction of ultrasonic lesions, post-mortems were performed, as were histological examinations of normal and damaged tissue. There was clear demarcation between ablated and normal tissue. Provided that simple rules on exposure technique had been observed, there was no evidence of inadvertent tissue damage, either locally to the treatment site, or in the tissue lying between the source and the target. This study is a useful step in demonstrating the feasibility of clinical trials for the use of this technique in treating bladder tumours and solitary liver metastases.

Lesion development in focused ultrasound surgery: a general model.

An analytical model has been constructed for the process of formation of thermal lesions in tissue, resulting from exposure to intense, highly focused ultrasound beams such as may be used in minimally invasive surgery. The model assumes a Gaussian approximation to beam shape in the focal region and predicts, for any such focal beam, the time delay to initiation of a lesion and the subsequent time course of growth of that lesion in lateral and axial dimensions, taking into account the effects of thermal diffusion and blood perfusion. The necessary approximations and assumptions of the model are considered. Comparison of predictions with experimentally measured data on excised pig liver indicate generally good agreement. Comparisons are also made of this theory with previously published data on exposure-time dependence of lesioning threshold intensity. Deficiencies are identified in existing practice for measuring and reporting acoustic exposures for focused ultrasound surgery, and the proposal is therefore made that a quantity that would be more satisfactory, from the viewpoints both of metrology and biophysical relevance, is the intensity spatially averaged over the area enclosed by the half-pressure-maximum contour in the focal plane, as determined under linear conditions, provisionally denoted as ISAL.

Two similar but atypical strains of coryneform group A-4 isolated from patients with endophthalmitis.

Corynebacterium species and other coryneform organisms isolated from clinical specimens are frequently considered contaminants. We isolated two strains of a gram-positive organism from the vitreous fluid of two patients with endophthalmitis who had previously received intraocular lens transplants. The biochemical characteristics and gas chromatographic patterns of both isolates were similar to those of coryneform group A-4 strains. Major differences included esculin hydrolysis, nitrate reduction, growth pigment, and lactic acid production. These two strains along with a limited number of strains collected at the Special Bacterial Pathogens Laboratory (Division of Bacterial Diseases, Centers for Disease Control, Atlanta, Ga.) may represent a subgroup of coryneform group A-4. Results of in vitro susceptibility testing performed with antimicrobial agents commonly used to treat patients with bacterial endophthalmitis underscore the importance of determining MBCs for slow-growing organisms. This report cautions microbiologists not to discard organisms frequently considered contaminants when isolated from body fluids that are normally sterile and from patients receiving local steroids.