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Biomedical subjects

Maxwell V Meng

Publications and source records attributed to Maxwell V Meng.

At least 19 recordsLinked to original sources
PubMed2003

Cytology of morcellated renal specimens: significance in diagnosis and dissemination.

PURPOSE: Controversy surrounds the process of morcellation for retrieving laparoscopically removed specimens. The inability to assess tumor stage, increased difficulty in pathological examination and the potential for tumor spillage are cited as significant disadvantages of the technique. We examined cytological findings in bag washings after laparoscopic nephrectomy for benign and malignant diseases. MATERIALS AND METHODS: We prospectively obtained cytology washings from the retrieval bag after laparoscopic nephrectomy and manual morcellation. In 22 consecutive cases after specimen fragmentation in a LapSac (Cook Urological, Spencer, Indiana) the bag was thoroughly irrigated with 30 cc normal saline. This wash was then processed by ThinPrep (Cytyc Corp., Marlborough, Massachusetts) and stained with Papanicolaou stain. Standard pathological examination of the morcellated specimen was performed to determine renal histology. RESULTS: The histological diagnosis was clear cell renal carcinoma in 10 cases, multicystic renal carcinoma in 2, papillary renal cell carcinoma in 1, angiomyolipoma in 1, and oncocytoma in 1. Bag cytological results were accurate in 9 of 13 patients with carcinoma (69%), while in 3 cytological study provided additional information. In all 9 cases of benign histology, cytological findings were consistent with benign cellular features. Neoplastic cells were easily detected and classified into type and grade. CONCLUSIONS: Cytological examination of LapSac washings after specimen morcellation provided a pathological diagnosis in the majority of patients. This method may complement existing techniques and be useful for increasing the accuracy of pathological analysis of morcellated specimens. In addition, these data suggest that malignant cells are liberated during the morcellation process, which has significant implications for potential tumor dissemination.

Adult↗
PubMed2003

Techniques to optimize vascular control during laparoscopic donor nephrectomy.

OBJECTIVES: To review our experience with laparoscopic donor nephrectomy for kidney transplantation and describe our technique of vessel ligation. METHODS: We retrospectively analyzed the method of renal artery and vein control during the 97 laparoscopic donor nephrectomies performed at the University of California, San Francisco, since November 1999. In addition, we examined both donor and recipient outcomes after nephrectomy and transplantation in this cohort. RESULTS: Currently, we ligate the renal artery and renal vein using a single Hem-o-lok polymer clip and a single Endo-TA stapler, respectively, and divide the vessels using scissors without securing the graft-side vessels. In contrast to using the Endo-GIA stapler, there is no need to trim staples (approximately 5 mm) from the vessels before anastomosis. Excellent vessel length was achieved in all cases without donor complications, and 99% of recipients had long-term graft function. The only major complications (blood transfusion, conversion to open surgery) occurred early in the series when we used the Endo-GIA stapler to control the vessels. CONCLUSIONS: Although adequate vessel length is typically obtained during left donor nephrectomy, additional length can be achieved using our modification. This may facilitate right donor nephrectomy and help reduce complications, potentially increasing the recovery of right kidneys for transplantation. In addition, performing vessel ligation and division in separate steps is simple, does not change ischemic time, and appears to increase safety.

Anastomosis, Surgical↗
PubMed2003

Novel microlaparoscopic technique for peritoneal dialysis catheter placement.

We describe our technique of microlaparoscopic placement of continuous ambulatory peritoneal dialysis catheters. Visualization is achieved using a 2.7-mm microlaparoscope, and intra-abdominal manipulation, as well as catheter placement using the Seldinger technique, is accomplished through a single 5-mm port. The advantages of this method include accurate placement of the catheter, minimal patient morbidity, and immediate use of the catheter for peritoneal dialysis.

Catheterization↗
PubMed2003

Simplified pure laparoscopic bowel anastomosis.

Laparoscopic bowel anastomosis can be a challenging and time-consuming process. No detailed intracorporeal technique has been well described, and most laparoscopists use an extracorporeal technique, which has many disadvantages. We detail a simple, pure laparoscopic method that creates a capacious isoperistaltic side-to-side enteroenterostomy.

Anastomosis, Surgical↗
PubMed2003

Laparoscopic radical nephrectomy for suspected renal cell carcinoma in dialysis-dependent patients.

OBJECTIVES: To characterize the treatment and outcomes of laparoscopic nephrectomy for suspected renal cancer in patients with dialysis-dependent renal failure. Laparoscopic nephrectomy is currently an accepted modality in the treatment of renal cell carcinoma in many patients. However, the indications for the minimally invasive approach in patients with renal dysfunction are unclear. End-stage renal disease has multiple manifestations associated with increased operative morbidity that are potentially amplified during laparoscopy. METHODS: We reviewed our single-center experience for performing laparoscopic nephrectomy in patients with renal failure. Of patients receiving dialysis and having a kidney removed laparoscopically, 7 underwent the operation for suspected renal carcinoma because of a solid mass on imaging. The preoperative, intraoperative, and postoperative considerations were reviewed. RESULTS: Of the 7 patients, 5 (71%) underwent successful removal of the kidney by laparoscopy. The amount of blood loss (120 mL) and the median time to discharge after surgery (3 days) were comparable to published data and our experience in patients with normal renal function; however, the operative time (mean 294 minutes) was longer. No recurrences had been detected at the last follow-up examination (median 21 months, range 18 to 51). Despite meticulous attention to perioperative and anesthetic considerations, two complications were observed-ileus and necrotizing fasciitis of the flank. CONCLUSIONS: Pure laparoscopic nephrectomy for renal malignancy is feasible in patients with end-stage renal failure. However, this population is at increased risk of complications, despite maintaining the advantages of reduced blood loss and shorter hospitalization. The decision to proceed with laparoscopy and the selection of the specific surgical approach (transperitoneal or retroperitoneal) should be based on both surgeon experience and patient factors. In addition, careful preoperative preparation and intraoperative anesthetic management are crucial.

Adult↗
PubMed2003

Hellström technique revisited: laparoscopic management of ureteropelvic junction obstruction.

OBJECTIVES: To present our experience with the treatment of adult ureteropelvic junction (UPJ) obstruction using a laparoscopic Hellström vascular relocation technique. METHODS: Transperitoneal laparoscopy was performed in 35 patients for the management of UPJ obstruction. In 9 cases, we identified crossing lower pole vessels and performed the Hellström technique. We discuss our indications, intraoperative techniques, and outcomes when performing only vascular relocation in these patients. RESULTS: All 9 patients presented with long-standing flank pain and were identified as having UPJ obstruction (7 primary, 2 secondary) on radiographic imaging. The intraoperative decision to perform the Hellström technique was based on the presence of the crossing vessels, a grossly normal appearance of the ureter and UPJ, and a small renal pelvis. The crossing vessels were completely mobilized, displaced cephalad, and fixed using intracorporeal sutures. The mean operative time and blood loss was 164 minutes and 15 mL, respectively. At a mean follow-up of 19 months (range 14 to 31), the patients were asymptomatic with no evidence of obstruction on Lasix nuclear renography. CONCLUSIONS: Traditional treatment of UPJ obstruction, with or without crossing vessels, has been accomplished by pyeloplasty. Dismembered pyeloplasty is a standard method in cases of associated crossing vessels; however, we propose that the Hellström technique be considered in cases in which the ureter appears normal and the pelvic anatomy is unfavorable for transection and anterior reanastomosis of the ureter and pelvis. These considerations are particularly relevant during the laparoscopic approach in which intracorporeal suturing and knot tying are technically challenging.

Adolescent↗
PubMed2003

Imaging clinically localized prostate cancer.

At this time there is no highly sensitive and specific widespread radiographic test for local staging of prostate cancer. Future developments will likely require a combination of imaging modalities with utilization guided by risk-stratification models (Table 4). Staging data for all imaging tests discussed in this article are summarized in Tables 5 and 6. Clinically, conventional gray-scale TRUS remains the most frequently used tool because of its utility in guiding prostatic biopsies. Modifications of TRUS--including power and color Doppler, 3D imaging, and new ultrasound contrast agents and elastography--show promise in increasing the accuracy of ultrasound. Endorectal MRI may have some value for staging selected patients. The addition of prostatic MRS, which images the differential activity of metabolites, may increase the specificity of MRI. Newer techniques with finer voxel resolution may prove to be clinically useful. A large well-designed study evaluating the utility of MRI/MRS is currently being planned. Cross-sectional imaging of the pelvis with either MRI or CT should be used selectively as should radionuclide bone scans. Similarly, ProstaScint scans should be ordered selectively, either before or after primary therapy, rather than routinely in all patients.

Antibodies, Monoclonal↗
PubMed2003

Pathologic sampling of laparoscopically morcellated kidneys: a mathematical model.

BACKGROUND AND PURPOSE: Kidney morcellation permits tissue removal through a port site; however, standard methods of histopathologic examination of the numerous specimen fragments thus produced have not been established. We developed a model to guide pathologic evaluation of the morcellated kidney. MATERIALS AND METHODS: A mathematical model was created to determine the quantity of morcellated tissue needed to establish a diagnosis. Inputs into the equation included estimated lesion size, total specimen volume, and the desired certainty of identifying at least a portion of the lesion on pathologic analysis. Nomograms were calculated to illustrate the model and provide clinically relevant guidelines. RESULTS: The hypergeometric distribution was used to develop the formula: P = 1 - (1 - k/N)(n), where k/N represents the fraction of total specimen with tumor, n is the amount of specimen that must be sampled to yield a diagnosis, and P is the probability of encountering the tumor in the sampled tissue. The model provided nomograms that were feasible and would guide a practical approach to the pathologic analysis of laparoscopically morcellated specimens. CONCLUSIONS: The increasing application of laparoscopy to the removal of solid organs with suspected tumors has raised several important issues. Morcellation of these specimens precludes traditional pathologic examination and necessitates an alternative method of specimen sampling and diagnosis. We describe a novel, systematic model to assist in the histopathologic examination of morcellated specimens. Issues of pathologic staging remain unresolved, but this sampling system provides a nonarbitrary framework to help arrive at a histologic diagnosis.

Humans↗
PubMed2003

Expanded experience with laparoscopic nephrectomy and autotransplantation for severe ureteral injury.

PURPOSE: Complex injuries of the upper ureter with significant loss of length are difficult to manage. Traditional options include nephrectomy, bowel interposition and autotransplantation. The advent of laparoscopic donor nephrectomy has created a new option when preservation of functioning renal parenchyma is desirable. We update our experience with severe iatrogenic ureteral injuries requiring laparoscopic nephrectomy and autotransplantation. MATERIALS AND METHODS: Seven patients with severe ureteral injuries were referred for definitive management. In all cases preoperative evaluation demonstrated comparable split renal function and anatomy not amenable to routine reconstruction. Transperitoneal laparoscopic nephrectomy and autotransplantation to the ipsilateral pelvis were attempted. RESULTS: Of the patients 5 had a history of nephrolithiasis with intervention resulting in the ureteral injury and 5 underwent prior endoscopic or open management of the defects. All cases were associated with dense perinephric and perihilar fibrosis. Operative and warm ischemic times averaged 508 and 5 minutes, respectively. After ex vivo graft preparation, ureteral and vessel length and quality were adequate for transplantation in 6 cases. In the other patient the renal pelvis was not amenable for reconstruction. Urinary drainage consisted of ureteroneocystostomy in 2 cases and ipsilateral ureteroureterostomy in 4. There were no intraoperative complications and all grafts functioned immediately. Hospitalization averaged 6.4 days. At a mean followup of 17 months imaging studies demonstrated functioning renal autographs with a mean decrease in serum creatinine of 5%. CONCLUSIONS: Laparoscopic nephrectomy in conjunction with autotransplantation is a viable option for severe proximal ureteral loss. Acceptable perioperative morbidity and excellent graft function were obtained in all cases when the kidney was transplanted. Close cooperation with a transplant team is crucial to coordinate graft harvest, ensure appropriate organ preparation and select the optimal urinary anastomosis.

Adult↗
PubMed2003

Infections and urinary stone disease.

The relationship between urinary infections and stone formation has been recognized since antiquity and it has been over a century since bacterial degradation of urea was postulated to cause struvite stones. Specific therapy for urease-producing bacteria, such as urease-inhibitors and antibiotics, has allowed for treatment for this subset of urinary stones. Future directions for research include development of novel urease-inhibitors and chemicals to enhance the protective glycosaminoglycan layer. An improved understanding of the pathogenesis of calcium-based stones has led to the discovery of potential roles for nanobacteria and Oxalobacter formingenes. Methods of altering intestinal regulation of oxalate by reintroduction of lactic acid bacteria may significantly impact the treatment of calcium oxalate stones. The use of catheters, both urethral and ureteral, is common in the urinary tract and is associated with significant morbidity, primarily from associated infections. Catheters to prevent bacterial colonization and formation of biofilms have been created using various coatings, including ciprofloxacin, hydrogel, and silver. Use of these types of catheters may minimize infections and encrustation inherent with their placement in the urinary tract.

Animals↗
PubMed2002

Sociodemographic characteristics and health related quality of life in men attending prostate cancer support groups.

PURPOSE: Prostate cancer can be associated with anxiety, depression and fears of recurrence and side effects of treatment. Support groups may help meet the needs of patients with cancer by providing treatment information and emotional support. We describe men in prostate cancer support groups and compare them to a national registry. METHODS AND METHODS: Men attending prostate cancer support groups in the San Francisco Bay area completed a questionnaire including sociodemographic and clinical characteristics, health related quality of life items, satisfaction with treatment, relief of prostate cancer symptoms and bother from perceived side effects of treatment. Patients in support groups were compared to men enrolled in a national prostate cancer registry (Cancer of the Prostate Strategic Urological Research Endeavor). RESULTS: Men attending support groups had higher annual income and education levels, lower median serum prostate specific antigen and higher cancer grades than men in Cancer of the Prostate Strategic Urological Research Endeavor. Clinical stage was comparable for the 2 groups. Men in support groups were satisfied with treatment and alleviation from symptoms. Adjusting for ethnicity, marital status, age and type of treatment, sexual function scores were higher in men who attended support groups (p = 0.001). There was no statistically significant difference in bowel and urinary function between groups, although urinary function approached statistical significance at p = 0.05. Sexual and bowel bother scores indicated less bother for men in support groups (p < or = 0.025). CONCLUSIONS: Men enrolled in support groups have unique sociodemographic characteristics. Their health related quality of life appears to be better than that of other men with prostate cancer. Whether this is related to support group participation is not known. Additional studies are required to determine whether routine support group participation improves outcomes in men with prostate cancer.

Aged↗
PubMed2002

Current treatment and outcomes of perinephric abscesses.

PURPOSE: We characterize the treatment and outcomes of perinephric abscesses in a contemporary cohort of patients. MATERIALS AND METHODS: We reviewed the experience with perinephric abscesses at a single community based hospital. Abdominal computerized tomography (CT) was widely available during the study period and experience with radiographic guided percutaneous drainage was extensive. Therapy and intervention for individual patients were dictated by the treating physician. RESULTS: Of the 25 patients identified with perinephric abscesses 3 (12%) ultimately died. Although 40% had multiple risk factors for perinephric abscesses only 35% were identified at presentation. Urine cultures were positive in 72% of patients and CT had a diagnostic sensitivity of 92%. Ten patients with a mean abscess size of 1.8 cm. were treated with antibiotics alone (mean hospitalization 10 days) while 11 with a mean abscess size of 11 cm. received antibiotics and initial percutaneous drainage (mean hospitalization 30 days). Of the 11 patients treated with percutaneous drainage 4 ultimately required surgical exploration and nephrectomy. CONCLUSIONS: The clinical characteristics of perinephric abscesses have not changed significantly but improved imaging with CT allows earlier diagnosis and treatment, which likely contributed to the reduced mortality in our cohort compared to historical series. With accurate staging and careful followup, a variety of treatments can be successful, including antibiotics alone or in conjunction with percutaneous drainage and urinary drainage. Open surgical drainage and nephrectomy may eventually be required in some patients and should be considered if adequate drainage is not achieved.

Abscess↗
PubMed2002

Laparoscopic intracorporeal square-to-slip knot.

We review a laparoscopic, intracorporeal technique of securing the square knot. It is useful when a surgeon's knot is insufficient to maintain tissue approximation. Advantages include the use of standard tying methods, lack of extracorporeal knot creation or need for a pushing device, and ability to secure the knot in difficult locations.

Humans↗
PubMed2002

Contemporary patterns of androgen deprivation therapy use for newly diagnosed prostate cancer.

Although once reserved for the management of metastatic prostate cancer, androgen deprivation therapy (ADT) is being used increasingly to treat lower stages of disease. We sought to assess patterns of ADT use in a contemporary cohort of men newly diagnosed with prostate cancer. Men with newly diagnosed prostate cancer who had > or =12 months of follow-up evaluation were identified in a national disease registry of patients with prostate cancer. The patterns of ADT use, both primary and secondary, were characterized and stratified by risk according to prostate-specific antigen levels, clinical stage, and Gleason score. In a cohort of 1485 men, 46% underwent ADT at some point during their treatment: 41% as primary therapy (either sole therapy or neoadjuvant therapy), and 5% as secondary therapy. In all, 50% of men receiving initial ADT had low- or intermediate-risk disease characteristics. Among patients treated with radical prostatectomy and radiation therapy, neoadjuvant ADT was administered in 20% and 48% of patients, respectively. Secondary hormonal manipulation was observed in 5% and 7% of patients treated initially with surgery or radiation, respectively. ADT is commonly used to treat men with prostate cancer. Much of the use of ADT is in men with low- and intermediate-risk disease characteristics. The appropriateness of such therapy requires further study, including its effect, not only on disease endpoints, but also on resource utilization and health-related quality of life.

Androgen Antagonists↗
PubMed2002

Complete laparoscopic ileal cystoplasty.

INTRODUCTION: Laparoscopic enterocystoplasty provides a minimally invasive approach to bladder augmentation in the patient with a neurogenic bladder. In previously published reports, portions of the procedure were performed extracorporeally. We report our technique of complete intracorporeal laparoscopic enterocystoplasty. TECHNICAL CONSIDERATIONS: Important elements of the operation include (a) preoperative evaluation of patient compliance and videourodynamic studies; (b) cystoscopic placement of externalized ureteral stents; (c) transperitoneal placement of five radially dilating trocars; (d) identification of the cecum; (e) proximal mobilization of ileum sufficient for pelvic placement; (f) measurement of ileal length with segment of precut vessel loop; (g) vertical cystotomy after incising peritoneum and entering the space of Retzius; (h) ileal division and side-to-side anastomosis using endoscopic gastrointestinal anastomosis staplers; (i) detubularization and freehand intracorporeal suturing into a U-shaped configuration; (j) fixing ileal patch at the 6 and 11-o'clock positions; (k) completion of ileal-bladder anastomosis in quadrants with running sutures; (l) irrigation of bladder and placement of a closed suction drain in the pelvis; and (m) cystogram 4 weeks postoperatively. CONCLUSIONS: Pure laparoscopic enterocystoplasty is an advanced procedure that is technically feasible and yields excellent results, but has unproven benefits. We perform the entire operation intracorporeally with traditional instruments and do not rely on suturing devices or extracorporeal knots. Additional experience and technological developments may result in routine laparoscopic urinary augmentation and continent diversion.

Anastomosis, Surgical↗