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Biomedical subjects

B R Lee

Publications and source records attributed to B R Lee.

At least 37 records · Page 2Linked to original sources

Effect of time delay on surgical performance during telesurgical manipulation.

BACKGROUND: Telementoring allows a less experienced surgeon to benefit from an expert surgical consultation, reducing cost, travel, and the learning curve associated with new procedures. However, there are several technical limitations that affect practical applications. One potentially serious problem is the time delay that occurs any time data are transferred across long distances. To date, the effect of time delay on surgical performance has not been studied. MATERIALS AND METHODS: A two-phase trial was designed to examine the effect of time delay on surgical performance. In the first phase, a series of tasks was performed, and the numbers of robotic movements required for completion was counted. Programmed incremental time delays were made in audiovisual acquisition and robotic controls. The number of errors made while performing each task at various time delay intervals was noted. In the second phase, a remote surgeon in Baltimore performed the tasks 9000 miles away in Singapore. The number of errors made was recorded. RESULTS: As the time delay increased, the number of operator errors increased. The accuracy needed to perform remote robotic procedures was diminished as the time delay increased. A learning curve did exist for each task, but as the time delay interval increased, it took longer to complete the task. CONCLUSIONS: Time delay does affect surgical performance. There is an acceptable delay of <700 msec in which surgeons can compensate for this phenomenon. Clinical studies will be needed to evaluate the true impact of time delay.

Evaluation Studies as Topic↗

Laparoscopic live donor nephrectomy: outcomes equivalent to open surgery.

A shortage of kidney donors has contributed to the interest in laparoscopic live-donor nephrectomy. Three transperitoneal ports are used, as is an AESOP robot. To maintain urine flow, the donor is kept volume expanded during the procedure, and the pneumoperitoneum pressure is minimized. The most critical and hazardous part of the surgery is dissection of the renal artery and vein. Abundant periureteral tissue should be left to protect the blood supply. Harvest of the right kidney is more difficult. Placing the extraction incision in the right upper quadrant and using a Satinsky clamp instead of a stapling device at the origin of the renal vein will provide maximum venous length and help prevent postoperative thrombosis of the allograft. In the first 175 laparoscopic renal harvest procedures at Johns Hopkins, the complication rate was 14%, the rate of open conversion was 2%, and 3% of the patients required transfusions. These rates improved with experience. There was no significant difference in the performance of the allografts or the recovery of the recipients from what is seen after open kidney harvest. Wider acceptance of laparoscopic renal harvest will increase the number of donors and will be helped by development of methods and devices that shorten the learning curve.

Humans↗

Biomicroscopic vitreous observation using a 3 CCD video camera and a personal computer for image capture and archiving.

The purpose of this study is to evaluate the clinical usefulness of a newly developed biomicroscopic vitreous observation system. Vitreous observation was performed in 300 eyes with age- or disease-related vitreous changes using a 3 CCD video camera mounted on a slit-lamp biomicroscope and connected to a personal computer for real-time observation and especially for the capture and archiving of images. Various types of fundus lenses were used to scan the vitreous status systemically from the posterior pole to the vitreous base. This system allowed us to obtain and immediately review the images of the vitreoretinal relationship. The image quality was sufficient for clinical evaluation of the vitreous status. We were able to identify some variations of posterior vitreous detachments and clarify the changes of the vitreoretinal interface in the study eyes. This system is very useful for the dynamic observation and documentation of vitreous images in order to determine the role of vitreous in many vitreoretinal disorders. Furthermore it is more convenient and affordable than previous methods.

Adult↗

Laparoscopic telesurgery between the United States and Singapore.

INTRODUCTION: Telemedicine is the use of electronic digital signals to transfer information from one site to another. With the advent of a telepresence operative system and development of remote robotic arms to hold and manoeuvre the laparoscope, telemedicine is finding its role in surgery, especially laparoscopic surgery. CLINICAL FEATURES AND TREATMENT: We report two successful cases of laparoscopic surgery--radical nephrectomy and varicocelectomy for a 3-cm renal tumour and for bilateral varicoceles causing pain, where a less experienced laparoscopic surgeon in Singapore was telementored by an experienced laparoscopic surgeon located remotely in the United States. Both patients recovered uneventfully and returned home on postoperative day 4 and on the day of surgery, respectively. OUTCOME: This study demonstrates that telementored laparoscopic systems are feasible and safe, between countries halfway across the world. CONCLUSIONS: As the Internet expands in utility and the cost of higher bandwidth telecommunication lines decreases, even to remote countries, telementoring systems will become more affordable and may potentially pave the way for advanced surgical and laparoscopic applications and training for the future.

Humans↗

Bioimpedance: novel use of a minimally invasive technique for cancer localization in the intact prostate.

BACKGROUND: Prostate cancer is presently diagnosed by transrectal ultrasound (TRUS)-guided sextant needle biopsy. While echo texture of the tissue can prompt localization of tumor, it is presently imprecise. From 50-75% of men biopsied, based on an abnormal digital rectal examination (DRE) or elevated prostate-specific antigen (PSA) level, have negative biopsy results. Improvements in tumor localization during TRUS-guided prostate biopsy are greatly needed. Bioimpedance is an electrical property of biologic tissue. Electric current is limited in living tissue by highly insulating cell membranes; however, different tissue architecture such as cancer may impede current differently and allow detection of differences between normal and abnormal or malignant prostate tissue. Our goal was to assess the utility of bioimpedance measurements in differentiating tumor from normal prostatic tissue in an ex vivo model. METHODS: Bioimpedance was measured in six ex vivo prostates, which were removed for clinically localized prostate cancer. Two bioimpedance needles, 1 mm apart, were inserted 3 mm into the posterior surface of the prostate an average of 16 times per gland. Frequencies ranging from 100 kHz-4 MHz were used to obtain 594 bioimpedance measurements from the six glands. These measurements were then correlated with histology to determine the presence or absence of prostate cancer. RESULTS: Prostate cancer was found to have a higher impedance, of 932+/-170 ohms, compared to areas of no cancer within the same prostate, 751+/-151 ohms, P < 0.0001, at 2 MHz. This phenomenon was observed across all frequencies tested. CONCLUSIONS: This study demonstrates for the first time application of bioimpedance to distinguish areas of prostate cancer from areas of normal prostate. This technology may improve identification and localization of cancer within the prostate. Moreover, bioimpedance can potentially guide needle placement during prostate biopsy and thus improve sampling of tumors. Currently, our ex vivo model is limited by variables such as temperature and lack of blood flow. Further studies in an in vivo model will be needed to assess their effect.

Diagnostic Techniques and Procedures↗

Hydrogen peroxide suppresses U937 cell death by two different mechanisms depending on its concentration.

To investigate the mechanisms of H2O2 adaptation in mammalian cells, we exposed human U937 leukemia cells to 0.05 mM H2O2. This treatment significantly suppressed cell death and DNA fragmentation induced by a subsequent challenge with 1 mM H2O2. A more dramatic protection was observed when cells were pretreated with 0.25 mM H2O2. Pretreatment with either 0.05 or 0.25 mM H2O2 also imparted cells with a survival advantage against serum withdrawal and C2-ceramide treatment. H2O2 was found to be a mediator of cell death induced by serum withdrawal, but not by the addition of C2-ceramide. Interestingly, 0.25 mM H2O2 greatly induced glutathione peroxidase, a H2O2-consuming enzyme, whereas 0.05 mM H2O2 did not. Consistent with observation, pretreatment with 0.25 mM H2O2 resulted in a great reduction of cellular oxidant levels as determined by 2'7'-dichlorofluorescein fluorescence, and it also prevented elevation of oxidant levels upon subsequent challenge with 1 mM H2O2 or with serum withdrawal. These effects were not observed in cells pretreated with 0.05 mM H2O2. The sum of the data indicated that H2O2 suppresses cell death by two different mechanisms depending on its concentration: Relatively high concentrations enhance cellular antioxidant capacity, and lower concentrations block the lethal action of H2O2.

Adaptation, Biological↗

Production and characterization of monoclonal antibodies to porcine brain pyridoxal kinase.

Six monoclonal antibodies that recognize porcine brain pyridoxal kinase have been selected and designated as PK67, PK86, PK91, PK144, PK252 and PK275. A total of six monoclonal antibodies recognizing different epitopes of the enzyme were obtained, of which four inhibited the enzyme activity. When total proteins of porcine brain homogenate separated by SDS-PAGE were subjected to monoclonal antibodies, a single reactive protein band of molecular weight 39 kDa which comigrated with purified porcine pyridoxal kinase was detected. Using the anti-pyridoxal kinase antibodies as probes, the cross reactivities of brain pyridoxal kinase from human and other mammalian tissues and from avian sources were also investigated. Among human and all animal tissues tested, immunoreactive bands on Western blots appeared to have the same molecular mass of 39 kDa. These results indicate that mammalian brains contain only one major type of immunologically similar pyridoxal kinase, although some properties of the enzymes reported previously differed from one another.

Animals↗

Isolation and identification of succinic semialdehyde dehydrogenase inhibitory compound from the rhizome of Gastrodia elata Blume.

In our search for the anticonvulsant constituent of Gastrodia elata repeated column chromatographies guided by activity assay led to isolation of an active compound, which was identified as gastrodin on the basis of spectral data. Brain succinic semialdehyde dehydrogenase (SSADH) was inactivated by preincubation with gastrodin in a time-dependent manner and the reaction was monitored by absorption and fluorescence spectroscopic methods. The inactivation followed pseudo-first-order kinetics with the second-rate order constant of 1.2 x 10(3) M-1min-1. The time course of the reaction was significantly affected by the coenzyme NAD+, which affected complete protection against the loss of the catalytic activity, whereas substrate succinic semialdehyde failed to prevent the inactivation of the enzyme. It is postulated that the gastrodin is able to elevate the neurotransmitter GABA levels in central nervous system by inhibitory action on one of the GABA degradative enzymes, SSADH.

Aldehyde Oxidoreductases↗

Ablation of renal tumors in a rabbit model with interstitial saline-augmented radiofrequency energy: preliminary report of a new technology.

OBJECTIVES: To evaluate the efficacy of interstitial saline radiofrequency energy for reproducibly ablating nonmalignant (control) and malignant (the VX-2 tumor) renal tissue in a rabbit model, and to determine the ability of conventional gray-scale and power sonography to image the tumor and ablative process in real time before, during, and after treatment. METHODS: The VX-2 tumor was implanted beneath the renal capsule in 18 rabbit kidneys. Twelve days after implantation, 50 W of 500-kHz radiofrequency energy was delivered into the surgically externalized renal tumor and contralateral control kidney for 30 or 45-second treatment intervals using an interstitial saline-augmented radiofrequency probe (the virtual electrode). Localization of the tumor and response to treatment were imaged with gray-scale and power Doppler ultrasonography. The effect of radiofrequency and extent of the destructive process on benign and malignant renal tissue were evaluated histologically. RESULTS: Mean tumor size was 1.3 x 0.7 cm. Both 30 and 45-second treatment intervals provided marked tissue/tumor ablation. Gross anatomic and histologic analysis showed time-dependent ablated lesions averaging 1.4+/-0.3 x 1.0+/-0.3 cm (30-second treatment) and 1.8+/-0.4 x 1.5+/-0.3 cm (45-second treatment), with clear demarcation of the surrounding parenchyma. Conventional gray-scale sonography allowed visualization of the ablative process, and power Doppler ultrasound demonstrated changes in the vascular pattern of the tumor both before and after ablation. No immediate treatment-related complications were observed. CONCLUSIONS: These preliminary studies in a rabbit model demonstrate the feasibility of using the interstitial saline-augmented electrode to ablate small renal tumors and the ability to simultaneously visualize the ablative process using real-time ultrasonography. This technology may have the potential to treat small renal tumors in a minimally invasive manner in the clinical setting.

Animals↗

Implementation of spectral width Doppler in pulsatile flow measurements.

In this paper, we present an automatic beam-vector (Doppler) angle and flow velocity measurement method and implement it in pulsatile flow measurements using a clinical Doppler ultrasound system. In current clinical Doppler ultrasound flow velocity measurements, the axis of the blood vessel needs to be set manually on the B-scan image to enable the estimation of the beam-vector angle and the beam-vector angle corrected flow velocity (the actual flow velocity). In this study, an annular array transducer was used to generate a conical-shaped and symmetrically focused ultrasound beam to measure the flow velocity vectors parallel and perpendicular to the ultrasound beam axis. The beam-vector angle and flow velocity is calculated from the mode frequency (f(d)) and the maximum Doppler frequency (f(max)) of the Doppler spectrum. We develop a spectrum normalization algorithm to enable the Doppler spectrum averaging using the spectra obtained within a single cardiac cycle. The Doppler spectrum averaging process reduces the noise level in the Doppler spectrum and also enables the calculation of the beam-vector angle and flow velocity for pulsatile flows to be measured. We have verified the measurement method in vivo over a wide range of angles, from 52 degrees to 80 degrees, and the standard deviations of the measured beam-vector angles and flow velocities in the carotid artery are lower than 2.2 degrees and 12 cm/s (about 13.3%), respectively.

Blood Flow Velocity↗

Cloning and functional analysis of the Aspergillus oryzae conidiation regulator gene brlA by its disruption and misscheduled expression.

We cloned the brlA gene from Aspergillus oryzae genomic DNA using the A. nidulans brlA gene as a probe. A 3.1-kb EcoRI-BalI genomic DNA fragment was cloned and sequenced. The deduced amino acid sequence revealed 70% identity with A. nidulans BRLA and contained two C2H2 zinc finger motifs in its carboxyl terminus, and the promoter sequence contained a 43-bp highly conserved region, indicating that the cloned gene was an A. oryzae homologue of A. nidulans brlA. Disruption of the brlA gene by homologous recombination resulted in the loss of ability to form conidiophores. These results suggest that the brlA gene of A. oryzae plays a fundamental role in controlling conidiophore development. When the brlA gene was expressed under the control of the amyB promoter in A. oryzae transformants, highly differentiated and compact colonies were observed on a solid medium. The misscheduled expression of the brlA gene in submerged culture, in which conidiation does not normally occur, caused the development of complex conidiophore structures with vesicles, phialides and conidia.

Journal Article↗

Different antigenic reactivities of bovine brain glutamate dehydrogenase isoproteins.

The structural differences between two types of glutamate dehydrogenase (GDH) isoproteins (GDH I and GDH II), homogeneously isolated from bovine brain, were investigated using a biosensor technology and monoclonal antibodies. A total of seven monoclonal antibodies raised against GDH II were produced, and the antibodies recognized a single protein band that comigrates with purified GDH II on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot. Of seven anti-GDH II monoclonal antibodies tested in the immunoblot analysis, all seven antibodies interacted with GDH II, whereas only four antibodies recognized the protein band of the other GDH isoprotein, GDH I. When inhibition tests of the GDH isoproteins were performed with the seven anti-GDH II monoclonal antibodies, three antibodies inhibited GDH II activity, whereas only one antibody inhibited GDH I activity. The binding affinity of anti-GDH II monoclonal antibodies for GDH II (K(D) = 1.0 nM) determined using a biosensor technology (Pharmacia BIAcore) was fivefold higher than for GDH I (K(D) = 5.3 nM). These results, together with epitope mapping analysis, suggest that there may be structural differences between the two GDH isoproteins, in addition to their different biochemical properties. Using the anti-GDH II antibodies as probes, we also investigated the cross-reactivities of brain GDHs from some mammalian and an avian species, showing that the mammalian brain GDH enzymes are related immunologically to each other.

Animals↗

Secure transmission of urologic images and records over the Internet.

PURPOSE: Telemedicine has become a common method for the transmission of images and patient data across long distances. Our goal was to assess the efficiency and accuracy of Photomailer MD software, a store-and-forward telemedicine system, in the urologic setting. METHODS: Photomailer MD software was loaded on two computers in the host institution, one with a T1 connection to the Internet and the other with a dial-up modem connection (24,000 bits/second), and computers at three remote sites. A total of 14 clinical cases, comprised of digitized histories and radiographic images, were sent to the remote institutions four separate times using the four transmission modes available: nonencrypted, 56-bit encryption, 128-bit encryption, and 128-bit encryption with password. The following data points were recorded: file size before and after encryption, file transmission times, and diagnostic accuracy of the remote urologists. One-way ANOVA was used to compare mean values statistically, while the z-test was used to compare diagnostic accuracies. RESULTS: Encryption increased the file size by a mean of 37.8%, with the three encryption modes increasing file sizes by the same number of kilobytes. When a dial-up modem was used, encrypted files required a significantly longer transmission time (P < 0.05) than the unencrypted files. The same trend was seen with the T1 connection, although the differences often were not significant. When T1 transmission times were compared with modem times with other variables held constant, modem times were significantly longer (P < 0.05). Diagnostic accuracies for each of the three remote centers ranged from 85.7% to 100%. Differences in accuracy rates between attending physicians and residents were not significant. CONCLUSIONS: Photomailer MD provides a secure, convenient, and affordable method of transmitting patient images and records via the Internet. Transmission speed was significantly greater when using a T1 line and also tended to be faster when files were not encrypted. There was no significant difference in transmission time among the three encryption modes; therefore, 128-bit encryption with a password should be used to maximize security. Diagnostic accuracies were comparable to those in the literature. In general, 640 x 480-pixel resolution was adequate for urologic diagnoses, although higher-resolution images may improve accuracy.

Analysis of Variance↗

Laparoscopic renal cryoablation: acute and long-term clinical, radiographic, and pathologic effects in an animal model and application in a clinical trial.

OBJECTIVES: To evaluate renal cryosurgery by studying the feasibility of laparoscopic delivery and the radiographic characteristics and histopathologic effects in a porcine model using different freeze cycles. On the basis of the results, a clinical trial of laparoscopic cryosurgical ablation in select patients with clinical stage T1 renal tumors was started. MATERIALS AND METHODS: Twelve kidneys from six farm pigs underwent cryosurgery. Each kidney was treated with two freeze cycles to -180 degrees C. Six kidneys were retroperitonealized, and six were not. An abdominal CT scan was performed at various times to evaluate for the presence of urinoma or hematoma and to monitor lesion changes. Organs were harvested at times ranging from 24 hours to 13 weeks. Radiographic and histopathologic changes were recorded for each time period. Eight patients with small (average 2-cm) exophytic renal masses underwent laparoscopic biopsy and cryosurgical ablation using a 3- or 4.8-mm probe (Cryomedical Sciences Inc., Rockville, MD) for one 15-minute or two 5-minute freeze cycles to a temperature of -180 degrees C to extend the ice ball at least 7 mm beyond the tumor margin. RESULTS: Dense adhesions between the bowel and cryoablated renal tissue were encountered in all non-retroperitonealized kidneys, but no fistula formation was present. The retroperitonealized kidneys had minimal adhesion formation. None of the animals developed a urinary fistula. At 24 hours and 1 week, CT scanning demonstrated an enhancement defect corresponding to the region of the ice ball with no urinoma or hematoma. At 13 weeks, only a nonenhancing cortical defect was seen. At immediate harvest, hemorrhage was noted in the area of the ice ball with a sharp demarcation at the edge of the freeze zone. At 1 week, four distinct zones were seen: central necrosis, inflammatory infiltrate, hemorrhage, and fibrosis with regeneration. At 13 weeks, the necrotic tissue had been replaced with a circumscribed area of fibrosis. There were no intraoperative or postoperative complications in the eight patients. The estimated blood loss was 140 mL, and the mean hospital stay was 3.5 days. At a mean clinical follow-up of 7.7 (range 1-18) months and radiographic follow-up of 5 months; there have been no tumor recurrences or significant changes in the serum creatinine concentration. At 24 hours, there was an enhancement defect in the area of the ice ball. The CT images at 13 weeks showed a nonenhancing cortical defect in the area of the ice ball. CONCLUSIONS: Cryosurgery can be readily delivered laparoscopically, creating a discrete lesion at the time of treatment that appears to be consistent over time. In the animal studies, complete tissue necrosis developed in the freeze zone, followed by reabsorption, and by 13 weeks, fibrous tissue had replaced the defect. In the animal and human trials, there were no operative complications, urinomas, hematomas, or bowel or urinary fistulas. Follow-up imaging in human trials revealed a persistent nonenhancing defect in the area of the freeze zone. Long-term clinical follow-up will be necessary to determine the cancer-free survival rate.

Aged↗

Chronic effect of pneumoperitoneum on renal histology.

BACKGROUND AND OBJECTIVE: Transient intraoperative oliguria is a constant phenomenon during laparoscopic procedures. Laboratory studies have demonstrated that this effect is secondary to a decrease in renal blood flow caused by the pneumoperitoneum. With the advent of laparoscopic harvest of the kidney for renal transplantation, a concern is that increased intra-abdominal pressure may compound the effect of acute cold and warm renal ischemia during transplantation. Acute transient renal ischemia can produce chronic sclerosing histopathologic changes in native kidneys which are similar to those seen in chronic allograft rejection. The effect of positive-pressure abdominal pneumoperitoneum (15 mm Hg) on native kidneys was examined using a rodent model. The effects on renal function and histologic features were also studied. MATERIALS AND METHODS: Twenty-four Harlan Wistar-Furth rats were divided into four groups: controls, 1-hour pneumoperitoneum-91-day survival, 5-hour pneumoperitoneum-91-day survival, and 5-hour pneumoperitoneum-7-day survival. Control animals underwent placement of the Veress needle and anesthesia but no induction of pneumoperitoneum. At the time of sacrifice, blood was sampled for serum creatinine measurement. Both kidneys were harvested for frozen and permanent section and stained using hematoxylin and eosin. Specimens were graded for inflammatory and ischemic/sclerotic changes in the interstitium, tubules, glomeruli, and vasculature by a renal pathologist using a histologic score (0-3). RESULTS: In all groups, at a sacrifice interval of either 1 week or 3 months, there were no statistical differences in the histologic score, serum creatinine concentration, or renal weight. CONCLUSIONS: In a rodent model, no signs of chronic ischemic histologic changes were detected for a period of 3 months after up to 5 hours of pneumoperitoneum. As well, there was no change in the serum creatinine concentration.

Animals↗

13-year survival comparison of percutaneous and open nephroureterectomy approaches for management of transitional cell carcinoma of renal collecting system: equivalent outcomes.

BACKGROUND AND OBJECTIVE: Transitional cell carcinoma (TCC) of the renal collecting system traditionally has been managed by open nephroureterectomy with en bloc resection of a bladder cuff. However, for a select patient population with a solitary kidney or bilateral disease, the morbidity and mortality associated with chronic renal insufficiency and dialysis is deterring. In these situations, a more conservative approach such as antegrade percutaneous resection should be considered. The long-term disease-free outcome of percutaneous management in comparison with open nephroureterectomy has not been previously reported. We evaluated our experience with two surgical approaches to treat upper tract TCC: percutaneous resection and nephroureterectomy/nephrectomy to assess the clinical efficacy of these surgical modalities. PATIENTS AND METHODS: We retrospectively identified 162 patients who had clinically localized TCC of the upper urinary tract. Records were reviewed to identify those with 13-year follow-up (N = 110) in respect to tumor grade, stage, disease-free status, length of cancer-specific survival, and overall survival. Statistical analysis of the results of open nephroureterectomy/nephrectomy (N = 60) and percutaneous resection (N = 50) was performed using Kaplan-Meier survival curves and Student's t-test. RESULTS: All patients had disease in clinical stage Ta through T3. During a mean follow-up of 46.6 (range 6-150) months, grade 1 disease demonstrated little invasive potential. Of the disease-specific deaths, 60% (17/26) were of patients with grade 3 lesions, with a mean cancer survival period of 15.2 months after the initial procedure. Disease-specific survival rates after open and percutaneous approaches for grade 2 disease were 53.8 and 53.3 months, respectively (P > 0.05). CONCLUSIONS: Tumor grade appeared to be the most important prognostic indicator in patients with renal TCC regardless of the surgical approach. Grade 3 tumors were more aggressive, presenting in an advanced stage with invasion, and recurrences were usually associated with metastasis. In this population, nephroureterectomy is warranted if the patient is a surgical candidate. The percutaneous option for grade 1 or 2 disease may be extended beyond the population with solitary kidneys and a risk of chronic renal failure to be offered to healthy individuals with normal contralateral kidneys who are willing to abide by a strict and lengthy follow-up.

Adult↗

Retroperitoneal access for transperitoneal laparoscopy in patients at high risk for intra-abdominal scarring.

BACKGROUND AND PURPOSE: Adhesions from prior extensive open abdominal surgery can make initial transperitoneal access for laparoscopy hazardous. An alternative to open port placement is a retroperitoneal approach to the peritoneal cavity. We describe our retroperitoneal access for transperitoneal laparoscopy and evaluate the success of the subsequent laparoscopic procedure. PATIENTS AND METHODS: Eight patients with a history of abdominal surgery have undergone retroperitoneal access to the peritoneum prior to a laparoscopic urologic procedure. With the patient in a lateral decubitus position, the retroperitoneum is entered with a 10-mm Visiport device (US Surgical Corp., Norwalk, CT) along the posterior axillary line. A working space is bluntly created, the peritoneum identified anterior to the colon, and the endoscope passed through a peritoneotomy. The abdomen is then inspected, transperitoneal ports are strategically placed under direct vision, and the intended procedure is commenced. RESULTS: In all cases, retroperitoneal access to the peritoneum and subsequent trocar placement was successful. In five cases, the intended procedure was completed laparoscopically. In a case of bilateral ureterolysis, one side was completed laparoscopically; however, the other required open conversion. In two nephrectomies for xanthogranulomatous pyelonephritis (XGP), open conversion was necessary because of fibrosis. CONCLUSION: Retroperitoneal access to the peritoneal cavity permits safe and effective port placement when previous abdominal surgery makes initial transabdominal access difficult. However, despite successful access, in patients at risk for extensive perinephric fibrosis (e.g., XGP), a high incidence of open conversion may be expected.

Abdomen↗