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L R Kavoussi

Publications and source records attributed to L R Kavoussi.

At least 91 records · Page 5Linked to original sources

[Alternative endourologic methods for treatment of urethral stricture].

Advances in endoscopic instrumentation and techniques offer new alternatives for safe and effective treatment of urethral strictures. Visual internal urethrotomy, the standard treatment modality, is associated with new scar formation with stricture recurrence. This experience has led to the investigation of alternative techniques which would avoid or ameliorate this result. This article reviews the current literature and discusses these newer approaches, including balloon dilatation, laser urethrotomy, endoscopic urethroplasty, "cut to the light" and "core through" procedures, and urethral wallstent implantation.

Catheterization↗

A novel method of surgical instruction: international telementoring.

Telemedicine is the use of communication technologies to deliver health care. Telesurgical telementoring represents an advanced form of telemedicine, whereby an experienced surgeon can guide and teach practicing surgeons new operative techniques utilizing current video technology, medical robots, and high-band-width telecommunications. This technology can potentially enhance surgeons' education, increase patients' access to experienced surgeons, and decrease the likelihood of complications due to inexperience with new techniques. A personal computer-based system was developed to immerse a surgical specialist into a distant operating room utilizing public telephone lines. Telesurgical laparoscopic telementoring has successfully been implemented in 27 prior operations between the Johns Hopkins Bayview Medical Center and the Johns Hopkins Hospital, whereby the two institutions were separated by 3.5 miles. We report our experience in performing three successful international surgical telementoring operations, one in Innsbruck, Austria, and two in Bangkok, Thailand.

Adrenalectomy↗

The "mini-perc" technique: a less invasive alternative to percutaneous nephrolithotomy.

The disadvantages of standard percutaneous nephrolithotomy (PCNL) as compared with ureteroscopy or extracorporeal shock-wave lithotripsy include increased blood loss, greater pain, and longer hospital stay. A 13-Fr "mini-perc" technique using a ureteroscopy sheath for PCNL was developed in an attempt to address these drawbacks. Nine "mini-percs" have been performed in patients aged 40-73 years with stone burdens of < or = 2 cm2. On average, patients had 1.4 stones with a cross-sectional area of 1.5 cm2. The mean total procedure time, estimated blood loss, and hematocrit decrease were 176 min, 83 ml, and 6.6%, respectively. On average, patients used 14 mg of parenteral morphine and stayed 1.7 days in the hospital. There was no procedure-related complication or transfusion. Eight of nine kidneys (89%) were stone-free on early follow-up at a mean of 3.8 weeks. As compared with standard PCNL, the "mini-perc" technique has similar early success rates in selected patients and may offer advantages with respect to hemorrhage, postoperative pain, and shortened hospital stays.

Adult↗

Laparoscopic visual field. Voice vs foot pedal interfaces for control of the AESOP robot.

BACKGROUND: In order for robotic devices to be introduced successfully into surgical practice, the development of transparent surgeon/machine interfaces is critical. METHODS: This study evaluated the standard foot pedal for the AESOP robot compared to a voice control interface. Speed, accuracy, learning curves, durability of learning at 2 weeks, and operator-interface failures were analyzed in an ex vivo model. RESULTS: Foot control was faster and had less operator-interface failures. Voice control was more accurate as measured by "pass points." The foot control learning curve reached a plateau at the third trial, while the voice control did not fully plateau. Durability of learning favored the foot control but was not significantly different. CONCLUSIONS: Currently, the voice control is more accurate and has the advantage of not requiring the surgeon to look away from the operative field. However, it is slower and may require more attention as an interface. As voice recognition software continues to advance, speed and transparency are anticipated to improve.

Equipment Design↗

Laparoscopy for the acute abdomen in the postoperative urologic patient.

OBJECTIVES: Exploratory laparotomy offers the greatest diagnostic accuracy of intra-abdominal pathologic processes, but can be associated with significant morbidity. Laparoscopy provides diagnostic capabilities equivalent to that of open exploration, but with potentially less morbidity. We present 3 cases in which laparoscopy was used to diagnose and manage urologic patients with an acute abdomen in a postoperative period. METHODS: Three patients underwent laparoscopy between 1 and 14 days postoperatively for an acute abdomen (fever, elevated white blood cell count, and peritoneal signs). The initial procedures included a pubovaginal sling repair with fascia lata, endoscopic placement of a percutaneous gastrostomy tube, and a laparoscopic ureterolithotomy for a distal stone. RESULTS: In each of the 3 patients laparoscopy revealed misplacement or malfunction of a previously placed tube. In all cases, the patient was managed laparoscopically without the need for laparotomy. CONCLUSIONS: These cases demonstrate the feasibility of laparoscopy to provide diagnostic and therapeutic solutions to postoperative urologic patients presenting with an acute abdomen.

Abdomen, Acute↗

Clinical significance of fever after percutaneous nephrolithotomy.

OBJECTIVES: In the immediate postoperative period after percutaneous stone removal, body temperature elevations are common. Pyrexia after a percutaneous nephrolithotomy (PCNL) generates concern because of the possibility of urinary extravasation and bacteremia. We reviewed our experience with PCNL to determine the clinical significance of a postoperative fever before discharge from the hospital. METHODS: Between July 1994 and December 1996, 63 patients underwent 69 PCNLs. Each had documented negative urine cultures preoperatively and received prophylactic antibiotics at the time of surgery. For each case, clinical and operative charts were reviewed to determine stone composition, fever during hospital stay, postoperative bacteriologic cultures, postoperative white blood cell count (WBC), and clinical course. RESULTS: Complete data were available for 66 procedures. Eight patients (12%) had at least one body temperature reading between 38.0 and 38.5 degrees C. Eleven patients (16.7%) had at least one temperature greater than 38.5 degrees C. Each patient with a temperature greater than 38.5 degrees C was hemodynamically stable with negative blood and urine cultures. No patient with a fever between 38.0 and 38.5 degrees C was cultured. Stone analysis did not demonstrate any association between postoperative fever and stone composition (including 22 struvite stones). Postoperative WBC also did not predict pyrexia. Fever alone did not prolong hospital stay. CONCLUSIONS: In patients with negative urine cultures who are prophylaxed with immediate preoperative antibiotics and maintained on postoperative antibiotics, pyrexia after PCNL does not require an immediate bacteriologic evaluation in those who are hemodynamically stable.

Female↗

Laparoscopic nephrectomy for renal cell cancer: evaluation of efficacy and safety: a multicenter experience.

OBJECTIVES: Although laparoscopic radical nephrectomy is a safe and minimally invasive alternative to open surgery, the long-term disease-free outcome of this procedure has not been reported. We evaluated our experience with the laparoscopic management of renal cell carcinoma to assess the clinical efficacy of this surgical modality. METHODS: Between February 1991 and June 1997, 157 patients at five institutions were retrospectively identified who had clinically localized, pathologically confirmed, renal cell carcinoma and had undergone laparoscopic radical nephrectomy. Operative and clinical records were reviewed to determine morbidity, disease-free status, and cancer-specific survival. Of the patients followed up for at least 12 months (n = 101), 75% had an abdominal computed tomography scan at their last visit. RESULTS: The mean age at surgery was 61 years (range 27 to 92) and all patients were clinical Stage T1-2,NO,MO. Fifteen patients (9.6%) had perioperative complications. During a mean follow-up of 19.2 months (range 1 to 72; 51 patients with 2 years or more of follow-up), no patient developed a laparoscopic port site or renal fossa tumor recurrence. Four patients developed metastatic disease, and 1 patient developed a local recurrence. The 5-year actuarial disease-free rate was 91%+/-4.8 (SE). At last follow-up, there were no cancer-specific mortalities. CONCLUSIONS: The laparoscopic surgical management of localized renal cell carcinoma is feasible. Short-term results indicate that laparoscopic radical nephrectomy is not associated with an increased risk of port site or retroperitoneal recurrence. Longer follow-up is necessary to compare long-term survival and disease-free rates with those of open surgery.

Adult↗

Laparoscopic pyeloplasty. Indications, technique, and long-term outcome.

Laparoscopic pyeloplasty is one of several minimally invasive treatment options for UPJ obstruction. In fact, several endoscopically and fluoroscopically controlled methods of incising the obstructed UPJ are now available that are significantly less invasive and less morbid in comparison with open pyeloplasty. However, the long-term success rates of these incisional techniques are less than the rates reported for open pyeloplasty. Several causes of obstruction may be present in the primarily obstructed UPJ, including kinking or compression related to crossing vessels or intrinsic narrowing at the UPJ. One potential reason for the inferior success rates of incisional methods in comparison with open pyeloplasty is that the former techniques address the intrinsically narrowed UPJ but may not address extrinsic problems such as kinking of the ureter associated with fibrotic bands or compression from crossing vessels. Laparoscopic pyeloplasty addresses all potential causes of obstruction. Any fibrotic bands kinking the ureter are divided, and the ureter is spatulated through the level of the UPJ prior to completion of the anastomosis. If a crossing vessel is encountered, a dismembered pyeloplasty is performed, the ureter and renal pelvis are transposed to the opposite side of the vessels, and the anastomosis is completed. An additional disadvantage of incisional techniques is the significant risk of hemorrhage following incision of the UPJ, with as many as 3% to 11% of patients requiring blood transfusion. Hemorrhage may occur owing to an errant anterior incision, the presence of a crossing vessel, incision into the renal parenchyma adjacent to the UPJ, or as the result of bleeding from the percutaneous access site. In contrast, mean estimated blood loss in the authors' series of 57 laparoscopic pyeloplasties was 139 mL, and none of the patients required blood transfusion. Although it is more morbid in comparison with retrograde or fluoroscopically controlled endopyelotomy, laparoscopic pyeloplasty seems at least comparable to antegrade percutaneous endopyelotomy in terms of the length of hospitalization and patient convalescence. Laparoscopic pyeloplasty, however, offers a higher success rate than with incisional techniques, not only from a radiographic standpoint but from a subjective standpoint as determined by the results of the analogue pain and activity questionnaire. The major disadvantage of laparoscopic pyeloplasty is the need for proficiency in laparoscopic techniques and for a longer operative time. As a result, the literature on laparoscopic pyeloplasty consists primarily of small series. Janetschek and co-workers reported on a series of 17 patients who underwent laparoscopic pyeloplasty, including 14 via a transperitoneal approach and 3 via a retroperitoneal approach. Procedures performed included ureterolysis alone, dismembered pyeloplasty, and nondismembered (Fenger) pyeloplasty. "Fenger-plasty" is similar to Y-V pyeloplasty and is performed by incising the UPJ longitudinally and closing the incision transversely in a Heineke-Mikulicz fashion. Janetschek and colleagues reported a 100% success in the eight patients who underwent dismembered pyeloplasty but believed that this technique was too cumbersome and should be reserved for patients with long stenoses, dorsally crossing vessels, or large renal pelvis. Because two of the four patients undergoing ureterolysis alone failed treatment, Janetschek and colleagues have abandoned this technique. They now prefer the Fenger-plasty technique, even in the setting of ventrally crossing vessels, because the technique can be performed quickly with one to three sutures, and the anastomosis can be sealed with fibrin glue and a flap of Gerota's fascia. Their experience with this technique, however, remains relatively limited. Technologic advances such as the Endostitch device have facilitated reconstructive laparoscopic procedures such as pyeloplasty. (ABSTRACT TRUNCATED)

Female↗

Robotic surgery in urology.

The demand for improved surgical performance and reduced health care costs have led to the evaluation of surgical robotic systems. Robotic devices to assist urologists with transurethral resection of the prostate, percutaneous renal access, and laparoscopy are currently in development or are already in clinical use. The rapid advances made in telecommunication technology also have allowed for the development of telesurgical systems that permit surgeons to participate in surgery from a remote location. In the twenty-first century, surgical robots will be efficient, invaluable, and safe adjuncts to urologic practice.

Humans↗

Laparoscopic renal biopsy.

BACKGROUND: Renal biopsy continues to be a pivotal tool and frequently indispensable diagnostic procedure in the clinical assessment of proteinuria and or unexplained renal disease. Laparoscopic renal biopsy has recently been reported as an alternative to open renal biopsy. METHODS: Thirty-two patients who had proteinuria and/or renal insufficiency underwent laparoscopic renal biopsy at our center. The indications for biopsy included failed percutaneous biopsy (N = 3), morbid obesity (14), solitary kidney (5), chronic anticoagulation/coagulopathy (6), religious consideration (refusal of potential blood transfusion) (2), multiple bilateral renal cysts and body habitus (1 case each). The kidney was approached via a laparoscopic retroperitoneal route (retroperitoneoscopy) using a two port technique. The lower pole of the kidney was localized using blunt dissection, laparoscopic cup biopsies were performed, and hemostasis was achieved using standard techniques. RESULTS: All biopsies were successfully completed laparoscopically with sufficient tissue obtained for histopathological diagnosis in all cases. Mean estimated blood loss was 25.9 ml (range 5 to 100). None of the patients required parenteral narcotics during the perioperative period. Operative time ranged from 0.8 to 3.0 hours (mean 1.5). Mean hospital stay was 1.7 days (range 0 to 7). Sixteen patients were treated as outpatients. Patients returned to normal activity at a mean of 1.7 weeks (range 0.3 to 3.0) postoperatively. In one patient, the spleen was inadvertently biopsied without consequence. An additional patient developed a postoperative 300 cc perinephric hematoma that resolved without the need for intervention. One postoperative mortality occurred on postoperative day seven secondary to a perforated peptic ulcer in a patient undergoing high-dose steroid therapy for lupus nephritis. CONCLUSION: Laparoscopic renal biopsy is a safe, reliable, minimally invasive alternative to open renal biopsy for patients in whom a closed percutaneous approach is either a relative or absolute contraindication, which can be performed on an outpatient basis.

Adolescent↗

Stereotactic mechanical percutaneous renal access.

Obtaining accurate percutaneous renal access when treating intrarenal disease requires substantial skill. Robotic devices have been used in a variety of surgical applications and have been successful in facilitating percutaneous puncture while improving accuracy. Laboratory models of robotic devices for percutaneous renal access have also been developed. However, several technical hurdles need to be addressed. One relates to the device-patient interface. As a first step in creating a complete robotic system, a mechanical arm (PAKY) with active translational motion for percutaneous renal access has been developed and clinically assessed. The PAKY consists of a passive mechanical arm mounted on the operating table and a radiolucent needle driver that uses a novel active translational mechanism for needle advancement. The system utilizes real-time fluoroscopic images provided by a C-arm to align and monitor active needle placement. In vitro experiments to test needle placement accuracy were conducted using a porcine kidney suspended in agarose gel. Seven copper balls 3 to 12.5 mm diameter were placed in the collecting system as targets, and successful access was confirmed by electrical contact with the ball. The PAKY was then used clinically in nine patients. The number of attempts, target calix location, calix size, and time elapsed were evaluated. In the in vitro study, successful needle-ball contact occurred the first time in all 70 attempts, including 10 attempts at the 3-mm balls. Clinically, percutaneous access to the desired calix was attained on the first attempt in each case. The mean target calix diameter was 14.7 mm (range 7-40 mm). The mean time elapsed while attempting access was 8.2 minutes. No perioperative complications attributable to needle access occurred. Early experience indicates that the PAKY provides a steady needle holder and an effective and safe end-effector for percutaneous renal access. This device may provide the mechanical platform for the development of a complete robotic system capable of creating percutaneous renal access.

Adult↗

Laparoscopic renal surgery in patients at high risk for intra-abdominal or retroperitoneal scarring.

Prior open abdominal or renal surgery has been considered a relative contraindication to laparoscopic surgery because of the likelihood of adhesion formation and perinephric scarring, which results in difficulty obtaining access to the peritoneal cavity and during surgical dissection. The purpose of this study was to examine the feasibility and morbidity of laparoscopic renal surgery in patients at high risk for intra-abdominal or retroperitoneal scarring. Twenty-four patients who underwent laparoscopic renal surgery at our institution gave a history of significant open abdominal or renal surgery. Seven patients had undergone prior open extraperitoneal (N = 6) or percutaneous (N = 1) renal procedures, 10 patients had undergone prior open laparotomy for various reasons, and 7 patients had undergone open pelvic surgery. The mean interval from the prior operation to laparoscopic renal surgery was 16.5 years (range 0.3-44 years). Operative time, estimated blood loss, incidence of complications, perioperative parenteral narcotic use, length of hospitalization convalescence, and degree of intra-abdominal and retroperitoneal scarring were assessed. Patients who developed complications were compared with patients who did not. No difficulty was encountered while obtaining initial access to the peritoneal cavity or retroperitoneal space. No bowel or visceral injuries occurred during Veress needle or trocar placement. The laparoscopic procedure was completed successfully in all cases. The mean operative time was 4.3 (range 2.0-10.9) hours. The mean estimated blood loss was 266 mL (range 50-1200 mL). There were eight complications (overall complication 33%) including three major and five minor complications. Patients who developed complications had a higher total scarring score that those who did not (p = 0.01). For experienced laparoscopic surgeons, laparoscopic renal surgery in patients who have a history of open abdominal or renal surgery can be successful. Access via the transperitoneal or retroperitoneal route can be obtained safely, and the procedure usually can be performed in a timely fashion. However, a relatively high perioperative complication rate can be expected, particularly for those patients with significant intraperitoneal and retroperitoneal scarring.

Abdomen↗

Factors involved in gas embolism after laparoscopic injury to inferior vena cava.

This study evaluated the incidence and factors involved in the occurrence of gas embolism after laparoscopic injuries. A 5-MHz transesophageal echocardiographic (TEE) probe was placed in 11 anesthetized pigs and used to examine the right cardiac chambers and pulmonary artery. A calibrated carbon dioxide analyzer continuously measured end-tidal carbon dioxide (ETCO2). The ventilatory settings were adjusted to achieve a baseline ETCO2 between 25 and 28 mm Hg. A blinded dose-response curve for TEE and ETCO2 measurements were created by injecting 0.0007 to 1.5 mL/kg of CO2 gas intravenously. Venotomies (N = 22) were created laparoscopically in the inferior vena cava (IVC) of the study animals. All TEE images were videotaped and correlated with laparoscopic events. Embolic episodes were classified by comparison with images recorded during the bolus studies. A variety of methods for obtaining hemostasis and repairing the venotomies were evaluated and their effects on gas embolism were studied. No emboli were noted when the venotomies were bleeding freely, the hole was directly occluded, or the proximal IVC was compressed. Marked embolism was seen with distal IVC occlusion or when there had been significant blood loss. In this situation, manipulation of the hole and higher intraperitoneal pressures led to higher degrees of embolization. No emboli were seen in an open control group except after significant bleeding. The TEE is the most sensitive method of detecting gas emboli; however, the majority of episodes are not clinically significant. Embolism of CO2 occurs when central venous pressure is decreased by blood loss or distal compression. When significant venous bleeding occurs, intravascular volume should be maintained and the bleeding site should be directly occluded.

Animals↗

Utility of the harmonic scalpel for laparoscopic partial nephrectomy.

Laparoscopic partial nephrectomy (LPN) remains a technically challenging procedure largely because of the lack of methods for obtaining consistent parenchymal hemostasis. The objective of this study was to determine if the extent of resection influences the ability of the harmonic scalpel to achieve hemostasis and to define the cases in which the harmonic scalpel is appropriate for LPN. Thirty LPNs were performed in a 25-kg domestic pig model. The blunt blade of the laparoscopic harmonic scalpel (LaparoSonic Coagulating Shears; Ethicon Endo-Surgery, Cincinnati, OH) at power level 5 was used to divide the parenchyma. Control of the renal hilar vessels was not obtained. Three standardized types of resections were performed: I = peripheral wedge biopsy; II = upper- or lower-pole nephrectomy; and III = heminephrectomy. Bleeding was graded on a scale from 0 to 4: 0 = no hemostasis; 1 = steady bleeding; 2 = moderate bleeding; 3 = parenchymal oozing; and 4 = dry. Hemostasis grades of 2 or less were clinically significant bleeding necessitating supplemental coagulation. The mean hemostasis scores showed a significant (P < 0.02) trend toward inadequate hemostasis with increasing extent of resection: 3.3 for Type I, 3.0 for Type II, and 2.4 for Type III. The percent of kidneys with grade 2 bleeding or worse was 9% for Type I surgery, 25% for Type II, and 57% for Type III. Successful hemostasis with the harmonic scalpel correlates with the extent of parenchymal resection in the porcine model. Most wedge excisions can be done with the harmonic scalpel alone, whereas larger resections necessitate supplemental coagulation. On the basis of this study, heminephrectomies with the harmonic scalpel are not recommended because of the high incidence of significant hemorrhage.

Animals↗