Biomedical subjects

Lee E Ponsky

Publications and source records attributed to Lee E Ponsky.

6 recordsLinked to original sources

PubMed2006

Retrograde endopyelotomy: a comparative study of hot-wire balloon and ureteroscopic laser.

PURPOSE: This study compared the immediate and long-term results and complications of hot-wire balloon endopyelotomy and ureteroscopic holmium laser endopyelotomy. PATIENTS AND METHODS: Between March 1994 and January 2002, 64 patients with a primary (N = 52) or secondary (N = 12) ureteropelvic junction obstruction underwent retrograde endopyelotomy using either a fluoroscopically guided hot-wire balloon incision (N = 27) or a ureteroscopically guided, direct-vision holmium laser incision (N = 37). This study group included 46 women and 18 men aged 13 to 79 years (mean 38.9 years). The indications and contraindications to a retrograde approach were identical in each group and included documented functionally significant evidence of obstruction, no upper-tract stones, obstruction <2 cm, and no radiographic evidence of entanglement of crossing vessels at the ureteropelvic junction. Immediate and long-term outcomes were obtained from a prospective registry, with success defined as resolution of symptoms and radiographic relief of obstruction as determined by follow-up with intravenous urography, diuretic renography, or both. Follow-up ranged from 39 to 133 months (mean 75.6 months). RESULTS: Length of hospital stay, indwelling stent duration, and long-term success rates (77.8% v 74.2% in the hot-wire balloon and holmium-laser group, respectively) were equivalent. However, two patients in the hot-wire balloon group developed bleeding necessitating transfusion and selective embolization of lower-pole vessels. No patient in the ureteroscopic group suffered a major complication. CONCLUSIONS: These two alternatives for retrograde endopyelotomy provide comparable success rates for similarly selected patients. However, because significant hemorrhagic complications developed with greater frequency in those treated with the hot-wire balloon, our preference is for a ureteroscopic approach, as it allows direct visual control of the incision and thus, a lower risk of significant bleeding.

Adolescent↗

PubMed2004

Laparoscopic transuterine fetal vesicostomy: a feasibility study.

PURPOSE: We evaluate the feasibility of applying minimally invasive techniques for fetal vesicostomy. We also evaluate whether transuterine fetal vesicostomy can be performed laparoscopically. MATERIALS AND METHODS: A total of 25 pregnant ewes were time dated at approximately 90 days of gestation. With the animals under general anesthesia a low open abdominal incision was made and the uterus was brought out through the incision. With a 14 gauge needle the amniotic sac was filled with 1 to 2 l warm glycine. Three to 4, 5/12 blunt tip balloon trocars were placed in the uterus. Using laparoscopic techniques, a low transverse incision was made in the fetal abdomen, the bladder was opened at the dome and 2 running sutures were placed approximating the fetal abdominal wall to the edge of the fetal bladder. The trocar sites in the uterus were closed, and the maternal abdominal incision was closed. RESULTS: Of the 25 pregnant ewes the technique was developed in the initial 15. In the subsequent 10 animals the complete procedure was accomplished successfully. Following these 10 procedures 5 abortions occurred on postoperative day 2, and there was 1 intrauterine fetal demise. Three fetuses were alive and delivered by cesarean section on postoperative days 10, 30 and 31. In the first fetus in which we used an interrupted suture for the vesicostomy a large hernia was noted at the vesicostomy site. The other 2 fetuses had a patent, well healed vesicostomy and were alive at cesarean section delivery on postoperative days 10 and 31. The last fetus was allowed to deliver at term by standard vaginal delivery. The fetus was alive and well, and the vesicostomy had strictured down to a pinhole in size, which was not unexpected as it was not an obstructed model. CONCLUSIONS: Although technically challenging, transuterine laparoscopic fetal vesicostomy is technically feasible in the ewe model. Continued evaluation of this technique should include intensive fetal monitoring and the use of tocolytics to decrease the incidence of spontaneous abortion.

Animals↗

PubMed2003

Initial evaluation of Cyberknife technology for extracorporeal renal tissue ablation.

OBJECTIVES: To determine whether Cyberknife technology can be applied to renal tissue safely and effectively. The goal was to achieve the high efficacy of a surgical treatment, with the low morbidity of a noninvasive intervention. METHODS: The Cyberknife is a frameless, image-guided radiosurgical device. This innovative extracorporeal treatment combines a linear accelerator mounted on a highly maneuverable robotic arm. The Cyberknife is unique in that it divides the high-dose radiation necessary to ablate the lesion completely into up to 1200 beams. Each one of these beams of radiation has a significantly reduced dose. Therefore, the individual dose of each beam is essentially benign to the pathway and surrounding tissue. However, at the focal point of these beams, the dose is additive, and the desired ablative dose is attained. Predetermined "lesions" in 16 kidneys were treated in vivo in the porcine model. Complete treatment was accomplished in one session per animal, with no complications. Gross and histologic evaluations were completed at 4, 6, or 8 weeks. RESULTS: The degree of radiation changes correlated with longer treatment intervals. After 8 weeks, the lesions showed complete fibrosis. The zones of complete fibrosis were characterized by dense, paucicellular connective tissue completely devoid of all normal kidney elements, including tubules and glomeruli. CONCLUSIONS: This initial preclinical evaluation of the Cyberknife for extracorporeal renal tissue ablation appears to be very promising and demonstrated its ability to ablate a targeted area precisely and completely with relative sparing of the surrounding tissue. This innovative technology introduces an exciting approach as a potential treatment option of renal masses in the future.

Animals↗

PubMed2003

Laparoscopic ureterocalicostomy: a feasibility study.

PURPOSE: Ureterocalicostomy is occasionally indicated for reconstruction of recurrent, recalcitrant ureteropelvic junction obstruction associated with postoperative fibrosis and a relatively inaccessible renal pelvis. We investigated the feasibility of performing laparoscopic ureterocalicostomy in a survival porcine model. Anatomical, histological and chronic functional outcomes were evaluated. MATERIALS AND METHODS: Laparoscopic ureterocalicostomy was performed in 10 survival female swine. A ureteropelvic junction obstruction model was created by laparoscopic ligation of a 2 to 3 cm. segment of upper ureter. After an interval of complete ureteropelvic junction obstruction laparoscopic ureterocalicostomy was performed in a manner duplicating the steps of conventional open surgery. After transverse amputation of the lower renal pole end-to-end anastomosis of the proximal ureter to the inferior calix was formed by laparoscopic freehand suturing and knot-tying techniques. RESULTS: Mean ureter stricture length was 2.2 cm. (range 1.7 to 3.1). Mean duration of obstruction before laparoscopic ureterocalicostomy was 6.3 days (range 2 to 18). Mean operative time for laparoscopic ureterocalicostomy was 165.3 minutes (range 105 to 240). Mean estimated blood loss was 145 cc (range 25 to 400). Mean stent duration in 6 pigs was 8.7 days (range 7 to 11). Excretory urograms demonstrated immediate function with symmetrical and unobstructed drainage in all operated renal units. At 4 to 8 weeks of followup no urine leaks were noted and histological examination documented complete urothelial healing without fibrosis or scar formation. CONCLUSIONS: Laparoscopic ureterocalicostomy is technically feasible in the porcine model and it effectively duplicates the established principles of open surgery. Our technique further extends the application of laparoscopic surgery for difficult ureteropelvic junction obstruction.

Anastomosis, Surgical↗

PubMed2003

Laparoscopic radical nephrectomy: incorporating advantages of hand assisted and standard laparoscopy.

PURPOSE: We present an approach to laparoscopic radical nephrectomy and intact specimen extraction, which incorporates hand assisted and standard laparoscopic techniques. MATERIALS AND METHODS: A refined approach to laparoscopic radical nephrectomy is described and our experience is reviewed. A low, muscle splitting Gibson incision is made just lateral to the rectus muscle and the hand port is inserted. A trocar is placed through the hand port and pneumoperitoneum is established. With the laparoscope in the hand port trocar 2 additional trocars are placed under direct vision. The laparoscope is then repositioned through the middle trocar and standard laparoscopic instruments are used through the other 2 trocars including the one in the hand port. If at any time during the procedure the surgeon believes the hand would be useful or needed, the trocar is removed from the hand port and the hand is inserted. RESULTS: This approach has been applied to 7 patients. Mean estimated blood loss was 200 cc (range 50 to 300) and mean operative time was 276.7 minutes (range 247 to 360). Mean specimen weight was 767 gm. (range 538 to 1,170). Pathologically 6 specimens were renal cell carcinoma (grades 2 to 4) and 1 was oncocytoma. Mean length of hospital stay was 3.71 days (range 2 to 7). There were no major complications. CONCLUSIONS: We believe that this approach enables the surgeon to incorporate the advantages of the hand assisted and standard laparoscopic approaches.

Blood Loss, Surgical↗

PubMed2002

Laparoscopic excision of suspected extra-adrenal pheochromocytoma located in the mesenteric root.

A 35-year-old woman presented with symptoms consistent with pheochromocytoma. Biochemical evaluation was equivocal. An MRI scan demonstrated an extra-adrenal high-intensity lesion on a T2-weighted sequence, which supported the suspicion of an extra-adrenal pheochromocytoma. Laparoscopically discovered to be located in the root of the small bowel mesentery, the 5-cm mass was excised along with a segment of small bowel. Pathology examination demonstrated fibromatosis, a benign lesion.

Adult↗