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Biomedical subjects

Peter G Schulam

Publications and source records attributed to Peter G Schulam.

12 recordsLinked to original sources
PubMed2007

Surgically relevant normal and variant renal parenchymal and vascular anatomy in preoperative 16-MDCT evaluation of potential laparoscopic renal donors.

OBJECTIVE: Using 16-MDCT, we describe and quantify the frequency and types of renal anatomic variants and findings relevant for preoperative evaluation and surgical planning for potential laparoscopic renal donors. MATERIALS AND METHODS: On 16-MDCT, 126 consecutive potential donors underwent scanning before contrast administration and after i.v. power injection of nonionic contrast material during the arterial, nephrographic, and excretory phases. On a 3D workstation, CT images were evaluated retrospectively in consensus by three abdominal imagers. The number and branching pattern of bilateral renal arteries and veins, including anomalies of the inferior vena cava and lumbar-gonadal axis, were categorized along with the frequency of incidental findings of the renal parenchyma and collecting system. RESULTS: Major arterial variants including supernumerary and early branching arteries were present in 16% and 21%, respectively, of left kidneys and 22% and 15%, respectively, of right kidneys. Major and minor venous variants were detected in 11% and 58% of left kidneys and 24% and 3% of right kidneys. Late confluence of the venous trunk was identified in 17% of left kidneys and 10% of right kidneys. Incidental parenchymal and urothelial abnormalities, most commonly cysts and calyceal calcifications, were identified in 30% of the kidneys. Other relevant incidental findings included focal infarcts, cortical scars, atrophic scarred kidney, and bilateral papillary necrosis. Urothelial variants included bilateral simple ureteroceles and rightsided complete duplicated collecting system. CONCLUSION: 16-MDCT angiography and urography allow confident detection and classification of a variety of anatomic and incidental anomalies relevant to the preoperative selection of potential laparoscopic renal donors and to surgical planning.

Adolescent↗
PubMed2006

Incidence of ureteral strictures after laparoscopic donor nephrectomy.

PURPOSE: Previous reports of laparoscopic donor nephrectomy have suggested that preservation of the gonadal vein with the specimen is important for preventing ureteral strictures. To test this hypothesis we examined our series of patients for the incidence of ureteral strictures when the gonadal vein was not preserved with the specimen during laparoscopic donor nephrectomy. MATERIALS AND METHODS: We reviewed the records of 300 consecutive patients at our institution who underwent laparoscopic donor nephrectomy between 2000 and 2005. Mean donor age was 36.7 years (range 18 to 68) in the 167 female and 133 male donors. Mean recipient age was 38.4 years. Average followup was 2 years. During ureteral dissection the gonadal vein was transected just distal to the renal vein and left in situ. The ureter was dissected and transected at the level of the common iliac vessels. Indwelling ureteral stents were used for all recipient ureteral reimplantations and left in place for 1 month. In the postoperative period transplant recipients were followed biweekly for serum creatinine function during month 1 and monthly thereafter. All patients with increased creatinine (greater than 1.3 mg/dl) or an increasing trend were evaluated with transplant renal ultrasound. Clinically significant ureteral stricture was defined as persistent hydronephrosis resulting in impaired renal function and the need for percutaneous nephrostomy tube placement or ureteroscopic management. RESULTS: After laparoscopic living donor transplantation without gonadal vein preservation we found no incidence of clinically significant ureteral stricture. CONCLUSIONS: Gonadal vein preservation with the specimen during laparoscopic donor nephrectomy is not necessary. Preservation of the periureteral blood supply is sufficient to prevent ureteral strictures.

Adolescent↗
PubMed2006

Utility of 16-MDCT angiography for comprehensive preoperative vascular evaluation of laparoscopic renal donors.

OBJECTIVE: Our objective was to determine the efficacy of 16-MDCT angiography in preoperative evaluation of vascular anatomy of laparoscopic renal donors. METHODS AND MATERIALS: Fifty-five consecutive renal donors (25 men and 30 women) underwent 16-MDCT angiography followed by donor nephrectomy. In the arterial and nephrographic phases, images were acquired with 60% overlap and 0.6-mm reconstruction in both phases after 120 mL of iohexol was injected at 4 mL/sec. On a 3D workstation, images were evaluated retrospectively by two abdominal imagers blinded to surgical results with respect to number and branching pattern of renal arteries and major and minor renal veins. These CT angiography results were compared with surgical findings. RESULTS: The surgically confirmed sensitivity of both reviewers (1 and 2) using the MDCT data for detection of renal arteries was 98.5% (65 of 66), and accuracies were 97.0% for reviewer 1 and 95.5% for reviewer 2. Sensitivity and accuracy detection of renal veins was 97% (61 of 63) and 98% (62 of 63) for reviewer 1 and reviewer 2, respectively. Sensitivity and accuracy detection of early arterial bifurcation (< 2 cm from aorta) was 100% (14 of 14), and sensitivity in detection of late venous confluence (< 1.5 cm from aorta) was 100% (8 of 8). All major renal venous variants were identified; reviewer 1 identified 78% (18 of 23) minor venous variants, and reviewer 2 identified 83% (19 of 23) minor venous variants. There were no hemorrhagic complications at surgery. Excellent agreement between reviewers (kappa = 0.92-0.97) was achieved for detection of normal and variant anatomy. CONCLUSION: 16-MDCT angiography enabled excellent preoperative detection of arterial anatomy and venous laparoscopic donor nephrectomy.

Adolescent↗
PubMed2005

Feasibility of nerve-sparing prostate cryosurgery: applications and limitations in a canine model.

BACKGROUND AND PURPOSE: In a canine model, we evaluated the feasibility of nerve-sparing cryosurgery by active warming of the neurovascular bundle (NVB). Furthermore, our aim was to determine if NVB warming increases the risk of acinar gland and stromal-tissue preservation in adjacent areas of the prostate. The effects of a single versus double freeze-thaw cycle on prostate tissue were also assessed. MATERIALS AND METHODS: Ten prostate lobes from five dogs were evaluated. Nine lobes from five dogs were treated with cryoablation using 17-gauge gas-driven cryoneedles. Seven lobes wre treated with active warming of the NVB using helium gas, and two lobes were treated without active warming. A single or double freeze-thaw cycle was utilized. Prostate tissue ablation and NVB preservation were evaluated in histologic sections. RESULTS: All seven prostate lobes treated with active warming demonstrated complete or partial NVB preservation. Four of these lobes had adjacent gland preservation. All lobes treated with a double freeze-thaw cycle showed complete and uniform ablation of prostate tissue. One of the three lobes treated with a single freeze-thaw cycle demonstrated incomplete ablation of the tissue. CONCLUSIONS: This is the first study investigating the feasibility of NVB preservation under controlled experimental conditions. In our canine model, NVB preservation with active warming was possible but not consistently reproducible. In some cases, NVB preservation with active warming may result in incomplete peripheral tissue ablation. A double, but not a single, freeze-thaw cycle induces complete and effective necrosis of prostatic tissue. These results have significant clinical applications when attempting nerve-sparing cryosurgical ablation of the prostate.

Animals↗
PubMed2005

The effects of intentional cryoablation and radio frequency ablation of renal tissue involving the collecting system in a porcine model.

PURPOSE: Ablative techniques for the treatment of urological malignancy are gaining acceptance and they are likely to become more widely used in clinical practice. Indications and limitations of the technologies are still evolving. In a porcine model we evaluated the safety and efficacy of cryotherapy and radio frequency ablation (RFA) of cortical and deep renal tissue. MATERIALS AND METHODS: In 11 swine argon gas based cryoablation or RFA of renal tissue adjacent to the collecting system was performed using a laparoscopic or percutaneous approach. Lesions created in renal units 30 days or 2 hours prior to harvest were termed chronic or acute. Using single or multiple 17 gauge cryoneedles or 3.0 mm cryoprobes and 2 freeze-thaw cycles (10-minute freeze and 5-minute thaw) 13 acute and 10 chronic cryolesions were made. Using a single 16 gauge umbrella-shaped RFA probe and 2 heating cycles to maximum impedance 13 acute and 4 chronic RFA lesions were made. Gross and microscopic tissue analysis was performed to assess lesion size and renal parenchymal, collecting system and arterial effects. Acute cryolesion size estimation by laparoscopic or transcutaneous ultrasound (US) was compared with pathological lesion size. RESULTS: Acute cryolesions on hematoxylin and eosin staining demonstrated uniform coagulative necrosis of renal parenchyma and chronic cryolesions demonstrated uniform necrosis with fibrous scar formation. Interlobar artery (adjacent to renal pyramid) preservation occurred in 7 of 13 acute and 5 of 9 chronic cryolesions. Urothelial architecture was preserved in 8 of 13 acute and 7 of 9 chronic cryolesions. Acute and chronic RFA lesions demonstrated indeterminate necrosis on hematoxylin and eosin staining, although triphenyl tetrazolium chloride staining of gross specimens confirmed necrosis most definitively in renal cortex. Interlobar artery preservation occurred in 6 of 13 acute and 3 of 4 chronic RFA lesions. Urothelial architecture was preserved in 1 of 13 acute and 2 of 4 chronic RFA lesions. Acute cryolesion dimensions measured by laparoscopic US equaled or underestimated lesion size measured grossly in all 6 cases. Lesion dimensions measured by transcutaneous US equaled or underestimated true lesion size in 3 of 6 cases. In 3 of 6 lesions transcutaneous US overestimated true lesion size by 20%, 76% and 260%, respectively. CONCLUSIONS: Renal cortical tissue can be effectively destroyed by cryoablation or RFA. However, treatment of deep parenchymal lesions with either modality may result in incomplete ablation. Cryosurgery but not RFA spares the collecting system in an acute setting. However, healing or regrowth of the urothelium may occur with time after RFA. Laparoscopic US is more accurate for cryolesion monitoring than transcutaneous US.

Animals↗
PubMed2004

Improved functional deflection with a dual-deflection flexible ureteroscope.

PURPOSE: To compare the maximal active deflection capabilities of a newly designed dual-deflection ureteroscope with those of a standard flexible ureteroscope. MATERIALS AND METHODS: The dual-deflection ureteroscope is similar in design to single-deflection ureteroscopes with the addition of a second, more proximal unidirectional deflection point, which is controlled with the index finger on the contralateral side of the instrument. We evaluated the maximal deflection angles achieved with this ureteroscope with no inserted devices as well as with 200-, 365-, and 550-microm laser fibers and a 3F Nitinol wire basket in the working port. We compared these angles with those obtained with the Dur-8 single-deflection ureteroscope. RESULTS: The dual-deflection ureteroscope allowed a superior maximum active deflection angle of 234.3 degrees with an empty working channel compared with only 143 degrees for the standard single-deflection ureteroscope. Instruments in the working channel dampened the active deflection of both ureteroscopes. The average maximum upward angles achievable with the single-deflection ureteroscope with the 200-, 365-, and 550-microm laser fibers and the 3F basket were 115.3 degrees, 92 degrees, 46.6 degrees, and 123.3 degrees, respectively. The average deflection angles with the dual-deflection endoscope deflected at the distal point were similar to those obtained with the single-deflection ureteroscope. In contrast, the average maximum deflection angles obtained with the dual-deflection endoscope deflected at both points with a 200-, 365-, and 550-microm laser fiber and a 3F basket in the working channel were 211 degrees, 183.3 degrees, 109 degrees, and 224 degrees, respectively. The degree of dampening by larger instruments was greater in the single-deflection than the dual-deflection ureteroscope. CONCLUSIONS: The double-deflection ureteroscope can achieve superior active deflection compared with a standard ureteroscope. The second active angle allows the use of larger instruments in the working port with a smaller impact on overall deflection. The double-deflection ureteroscope should be beneficial in the management of difficult-to-treat lower-pole renal calculi and may allow some patients who would have required percutaneous nephrolithotomy to undergo ureteroscopic management of their stone disease.

Humans↗
PubMed2003

Laparoscopic partial nephrectomy and minimally invasive nephron-sparing surgery.

Surgical extirpation remains the most effective therapy for renal cell carcinoma. The surgical management of renal masses has evolved away from radical nephrectomy and now includes nephron-sparing surgery for small tumors. Nephron-sparing surgery has similar cure rates and does not appear to compromise cancer control. As the detection of small renal masses by widespread abdominal imaging continues to increase, so will the demand for minimally invasive nephron-sparing procedures. Despite progress in surgical techniques, laparoscopic partial nephrectomy remains a technically challenging procedure. In this review, we discuss the challenges and recent advances in laparoscopic partial nephrectomy and other minimally invasive approaches to renal masses.

Carcinoma, Renal Cell↗
PubMed2003

Treatment of renal transplant ureterovesical anastomotic strictures using antegrade balloon dilation with or without holmium:YAG laser endoureterotomy.

OBJECTIVES: To report our results after antegrade endoscopic treatment of ureteral stenosis with balloon dilation with or without holmium laser endoureterotomy. Ureteral stenosis is the most common long-term urologic complication of renal transplantation. METHODS: From July 2000 to October 2002, 9 renal transplant patients with ureteral obstruction diagnosed by an increase in serum creatinine and radiologic evidence presented for endoscopic treatment. All patients were treated with nephrostomy tube drainage followed by antegrade flexible nephroureteroscopy and balloon dilation of the stricture. Three patients required holmium laser endoureterotomy during the same procedure because of fluoroscopic and endoscopic evidence of persistent stricture. All patients were treated with ureteral stents and nephrostomy tubes postoperatively. The median follow-up was 24 months (range 6 to 32). RESULTS: The site of stenosis was at the ureterovesical anastomosis in all patients, and the mean stricture length was 0.28 cm. Two patients had previously undergone ureteroneocystostomy for prior ureteral stenosis. Six patients (66%) required only balloon dilation, and 3 patients (33%) also required holmium laser endoureterotomy. The median ureteral stent and nephrostomy tube duration was 40 and 62 days, respectively. The mean serum creatinine level was 2.3 mg/dL at presentation and 1.7 mg/dL at the last follow-up visit. After a median follow-up of 24 months, the ureteral patency and graft function rates were both 100%. No perioperative complications occurred. CONCLUSIONS: Balloon dilation with or without holmium laser endoureterotomy was successful and safe in this group of renal transplant patients with short ureterovesical anastomotic strictures.

Catheterization↗
PubMed2003

Quality of life, pain and return to normal activities following laparoscopic donor nephrectomy versus open mini-incision donor nephrectomy.

PURPOSE: We evaluated pain, convalescence and health related quality of life in patients undergoing laparoscopic and open mini-incision donor nephrectomy. MATERIALS AND METHODS: We compared the records of consecutive patients who underwent laparoscopic and mini-incision open donor nephrectomy from our donor nephrectomy data base in retrospective fashion using 2 questionnaires. The first questionnaire evaluated postoperative pain, return to functioning time and satisfaction. The second questionnaire was the RAND 36-Item Health Survey, version 2, a standardized and validated health survey quality of life assessment tool. Mean patient sex, age and followup were similar for the 2 groups. All data were analyzed using the 2-tailed t test for independent variables with commercially available statistical analysis software. RESULTS: Pain in the laparoscopic group was significantly less than in the mini-incision group at all followup time points (p <0.05). Statistically significant differences demonstrated that laparoscopy led to more rapid recovery time in certain categories, including walking, discontinuation of prescribed oral pain relievers, return to driving, and resumption of normal work and home daily activities. More subjective questions in the survey showed high levels of acceptance for the 2 procedures. Using the RAND 36-Item Health Survey, version 2 health related quality of life was significantly higher in the laparoscopy group in 3 domains that measure bodily pain, physical functioning and emotional role functioning. However, each group scored at or above age matched American averages in all domains. CONCLUSIONS: The laparoscopy group had significantly less postoperative pain and required less time to return to normal functional activities than the mini-incision group. In addition, the laparoscopic group showed significantly higher quality of life scores than the mini-incision group in 3 domains.

Activities of Daily Living↗
PubMed2002

Use of heparin and protamine sulfate during laparoscopic donor nephrectomy.

BACKGROUND: Our aim was to evaluate the necessity of heparin and protamine administration during laparoscopic donor nephrectomy. METHODS: Data from 52 consecutive living-related laparoscopic donor nephrectomies performed at University of California Los Angeles between August 1999 and August 2001 were used for this analysis. For the purpose of this analysis, the patients were divided into three cohorts: group A received both heparin and protamine; group B received heparin only; and group C received neither. Intraoperative blood loss, length of admission, recipient creatinine at follow-up, and intraoperative and postoperative complications were compared between the groups. Statistical analysis was performed using a two-tailed test. RESULTS: There were no significant differences between the groups with regard to patient age and gender. Intraoperative blood loss did not differ between group B (99+/-73 mL) and group C (82+/-54 mL) ( =0.4). None of the patients required blood transfusion. No graft loss occurred in any group. Length of hospital stay, excluding any preoperative days, was similar (2.8+/-0.7, 2.9+/-1.6, and 2.5+/-0.8 days, for groups A, B, and C, respectively, ( >0.05). No systemic thromboembolic complications were noted in any of the groups. One patient in group B was converted to an open procedure because of a difficult dissection unrelated to heparin administration. The mean recipient creatinine levels at follow-up in the recipients of kidneys from groups A, B, and C were not significantly different (1.1, 1.3, and 1.3; >0.05) through the extended follow-up period of 691, 286, and 97 days, respectively. CONCLUSIONS: According to our experience, there is no apparent benefit in the administration of heparin alone or in the administration of protamine sulfate to reverse heparin anticoagulation during laparoscopic donor nephrectomy if heparin is given. This is not only in terms of bleeding complications but is also true in regard to recipient renal function through the follow-up period. It is important to note that our warm ischemic times were less than 2 minutes, because longer warm ischemic times may make the use of heparin a more important consideration. This is the first time that these questions have been studied in the laparoscopic donor nephrectomy population.

Adult↗