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Biomedical subjects

Christopher S Ng

Publications and source records attributed to Christopher S Ng.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneous bilateral retrograde intrarenal surgery for stone disease in patients with significant comorbidities.

BACKGROUND AND PURPOSE: Advances in endoscopic equipment have allowed urologists to access stones in virtually any location in the upper tracts. Where clinically appropriate, this approach may represent the preferred treatment option, regardless of stone size. We report the first description of simultaneous bilateral retrograde intrarenal surgery (SB-RIRS) in patients with both significant upper-tract stone burdens and comorbidities such as morbid obesity or heart disease. PATIENTS AND METHODS: Between September 2003 and April 2004, three men and one woman with an average of 62 years underwent a total of seven sessions of SB-RIRS. All four patients were referred from other urologists after failing prior treatments, including shockwave lithotripsy (five sessions) and RIRS (two sessions). The average stone burden was 8.8 cm. The procedures were performed by two surgeons operating simultaneously using two sets of video/holmium laser equipment. Flexible (7.5F) ureteroscopes were used to fragment and basket stone debris without the use of ureteral access sheaths. RESULTS: Three patients underwent a scheduled second-stage procedure to ensure adequate stone clearance. The average total and SB-RIRS-specific operative times were 256 and 131 minutes for the initial procedure and 235 and 95 minutes for the second-stage procedure, respectively. No major complications were noted. CONCLUSION: Simultaneous bilateral RIRS is an appropriate treatment option for stone patients with significant comorbidities.

Aged↗
PubMed2005

Newly designed laparoscopic retractable dissector and suture passer.

We introduce a novel laparoscopic instrument that performs as a dissector and retractable suture passer in preparation for intracorporeal knot tying. The newly designed instrument was developed at our institution to duplicate techniques of vessel ligation in open surgery.

Animals↗
PubMed2005

Prospective evaluation of interstitial laser coagulation of the prostate: importance of surgical technique and patient selection.

PURPOSE: To evaluate the impact of improvements in surgical technique and patient selection on overall outcomes of interstitial laser coagulation (ILC) of the prostate and to describe our treatment algorithm. PATIENTS AND METHODS: During a 4-year period, 66 men with bothersome lower urinary-tract symptoms underwent ILC of the prostate using the Indigo 830e Diode Laser System (Ethicon Endo-Surgery). Patients were assessed preoperatively and followed prospectively. Parameters included American Urological Association Symptoms Index, Quality of Life Scale, Problems Due to Symptoms Score, postvoiding residual volume, maximum flow rate, number of treatment punctures, and adverse events. One-year follow-up data were compared with baseline data using the Wilcoxon signed rank test or Fisher's exact test. Patients were stratified into those treated during the first 2 years (group 1) and those treated in the latest 2 years (group 2), corresponding to changes in surgical technique and patient selection. RESULTS: Maximum flow rates improved by 47% and 85% in groups 1 and 2, respectively, at 12 months postoperatively compared with baseline (P = 0.04)l. The mean number of punctures differed significantly, with 6.4 in group 1 and 8.4 in group 2 (P = 0.03). Subjective measures were significantly improved from baseline in both groups and did not differ between groups. The incidence of adverse events was similar in the two groups. CONCLUSIONS: Improvements in surgical technique and patient selection described herein corresponded to significantly higher maximum flow rates without an increase in adverse events.

Algorithms↗
PubMed2005

Looped silk tie: surgical technique for management of the renal vein during laparoscopic live-donor nephrectomy.

Laparoscopic live-donor nephrectomy has revolutionized the field of kidney transplantation and has been adopted in many tertiary centers as the method of choice in procuring kidneys. While standard techniques for laparoscopic live-donor nephrectomy have been well described in the literature, there continues to be ample discussion about renal-vein ligation. Endo-GIA and other commonly used vascular stapling devices can be costly and prone to mechanical failures and may not be applicable in certain anatomic situations. Vascular clips, although simple to use for arteries, are difficult to apply to large renal veins. To address these issues, we describe a simple, cost-effective method of control that can be used for both right and left renal veins, using a loop constructed from a 0 silk tie.

Adult↗
PubMed2005

Laparoscopic skills training using a webcam trainer.

PURPOSE: Many sophisticated and expensive trainers have been developed to assist surgeons in learning basic laparoscopic skills. We developed an inexpensive trainer and evaluated its effectiveness. MATERIALS AND METHODS: The webcam laparoscopic training device is composed of a webcam, cardboard box, desk lamp and home computer. This homemade trainer was evaluated against 2 commercially available systems, namely the video Pelvitrainer (Karl Storz Endoscopy, Culver City, California) and the dual mirror Simuview (Simulab Corp., Seattle, Washington). The Pelvitrainer consists of a fiberglass box, single lens optic laparoscope, fiberoptic light source, endoscopic camera and video monitor, while the Simuview trainer uses 2 offset, facing mirrors and an uncovered plastic box. A total of 42 participants without prior laparoscopic training were enrolled in the study and asked to execute 2 tasks, that is peg transfer and pattern cutting. Participants were randomly assigned to 6 groups with each group representing a different permutation of trainers to be used. The time required for participants to complete each task was recorded and differences in performance were calculated. Paired t tests, the Wilcoxon signed rank test and ANOVA were performed to analyze the statistical difference in performance times for all conditions. RESULTS: Statistical analyses of the 2 tasks showed no significant difference for the video and webcam trainers. However, the mirror trainer gave significantly higher outcome values for tasks 1 and 2 compared to the video (p = 0.01 and <0.01) and webcam (p = 0.04 and <0.01, respectively) methods. ANOVA indicated no overall difference for tasks 1 and 2 across the orderings (p = 0.36 and 0.99, respectively). However, by attempt 3 the time required to complete the skill tests decreased significantly for all 3 trainers (each p <0.01). CONCLUSIONS: Our homemade webcam system is comparable in function to the more elaborate video trainer but superior to the dual mirror trainer. For novice laparoscopists we believe that the webcam system is an inexpensive and effective laparoscopic training device. Furthermore, the webcam system also allows instant recording and review of techniques.

Clinical Competence↗
PubMed2005

Percutaneous access to upper pole renal stones: role of prone 3-dimensional computerized tomography in inspiratory and expiratory phases.

PURPOSE: We evaluated the role of noncontrast, prone position, inspiratory and expiratory 3-dimensional spiral computerized tomography (PIE-CT) for preoperative planning of percutaneous treatment in patients with complex upper pole renal calculi. MATERIALS AND METHODS: In this pilot study a total of 6 renal units in 4 women and 1 man with complex upper pole calculi who were candidates for percutaneous nephrolithotomy were evaluated with thin section PIE-CT. With the patient imaged in the prone position percutaneous access was simulated under 4 potential access conditions, including subcostal and intercostal, in inspiration and expiration. Each potential access was then deemed transpleural or extrapleural and minimally angulated or severely angulated cephalad. RESULTS: PIE-CT was performed uneventfully in all patients. Ideal nonangulated extrapleural percutaneous access was deemed possible in 5 of 6 renal units. However, inspiratory plus expiratory phases were necessary to identify the most suitable access site. In 2 renal units only 1 safe access site was identified. No pulmonary complications were noted in any of these patients. In 1 renal unit no suitable access could be identified and this patient was treated with laparoscopic caliceal diverticulectomy. CONCLUSIONS: Thin section PIE-CT offers 3-dimensionally rendered images that clearly demonstrate anatomical relationships among the kidney, calculi, pleura, diaphragm, ribs and surrounding organs. In this pilot study PIE-CT provided useful data for planning urological intervention for complex upper pole renal stones. This study also suggests that generalizations regarding the safety of upper pole access in the inspiratory or expiratory phase are not warranted.

Exhalation↗
PubMed2005

Complications of laparoscopic partial nephrectomy in 200 cases.

PURPOSE: We analyzed complications of the initial 200 cases treated with laparoscopic partial nephrectomy for a suspected renal tumor. MATERIALS AND METHODS: Since August 1999, 200 consecutive patients have undergone laparoscopic partial nephrectomy. Mean patient age was 61.6 years, mean body mass index was 29.9 and mean tumor size was 2.9 cm (range 1 to 10). There were 51 central tumors (25%) and 15 solitary kidneys (7.5%). A central tumor was defined as any tumor infiltrating up to the collecting system or renal sinus, during the excision of which entry into and repair of the collecting system was necessary. Mean estimated blood loss was 247 cc and mean operative time was 3.3 hours. Data on complications were obtained from a prospectively maintained computerized database and via telephone calls to patients and/or local referring physicians. RESULTS: A total of 66 patients (33%) had 1 or more complications, which were intraoperative in 11 (5.5%), postoperative in 24 (12%) and delayed in 31 (15.5%). Overall 30 patients (15%) had a non-urological complication and 36 (18%) had a urological complication, including hemorrhage in 19 (9.5%) and urine leakage in 9 (4.5%). Hemorrhage occurred intraoperatively in 7 cases (3.5%) and postoperatively in 4 (2%), while it was delayed in 8 (4%). Of patients with urine leakage none required reoperation, 6 (3%) required a Double-J stent (Medical Engineering Corp., New York, New York) only, 2 (1%) required a Double-J stent with computerized tomography guided drainage and 1 required no treatment. Open conversion was necessary in 2 patients (1%), reoperation was done in 4 (2%) and elective laparoscopic radical nephrectomy was performed in 1 (0.5%). CONCLUSIONS: Laparoscopic partial nephrectomy is an advanced procedure with potential for complications. It requires considerable experience with reconstructive laparoscopy.

Adolescent↗
PubMed2005

Bladder reconstitution with bone marrow derived stem cells seeded on small intestinal submucosa improves morphological and molecular composition.

PURPOSE: Tissue engineering has been used for bladder augmentations with small intestinal submucosa (SIS). Although favorable short-term outcomes have been reported, long-term followup has been poor. We investigate whether tissue engineering with stem cells improves the morphological and genetic composition. MATERIALS AND METHODS: A total of 33 Lewis rats (Harlan Laboratories, Indianapolis, Indiana) were used to investigate bladder augmentations with 4-layer SIS in certain groups, including the control group (sham operation), partial cystectomy with oversewn defect group (OG), augmentation with unseeded SIS group (USG) and augmentation with stem cell seeded SIS group (SSG). Bladders from 4 rats per group were harvested 1 and 3 months after surgery. Morphological analyses were performed using Masson's trichrome and immunohistochemical staining with cytokeratin AE1/AE3, smooth muscle alpha-actin and S100. Gene expression was evaluated using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for collagen I (CI), collagen III (CIII), cytokeratins 8 and 19, and smooth muscle myosin heavy chain (MHC). RESULTS: At 1 month trichrome staining revealed collagen admixed with indiscrete cells and morphology similar to that in controls in USG and SSG, respectively. Discrete smooth muscles fascicles and S100 staining were found in all groups except USG. Organized urothelium with increased basal cell layer staining was present in controls and SSG only. At 3 months increased collagen formation was present in OG and USG. Immunostaining showed hyperplasia of the urothelium with increased staining of the basal cell layer, discrete muscle fascicles and positive nerve staining in all groups. Using quantitative RT-PCR expression levels in SSG were more improved than in USG, especially for CI, CIII and MHC. This was further evident at 3 months when CI and CIII were over expressed in OG and USG but not in the control group or SSG. Furthermore, RT-PCR showed that cytokeratins 8 and 19, and MHC had greater expression levels in SSG than in USG. CONCLUSIONS: Bladder reconstitution occurs more rapidly using stem cell seeded SIS. Although in USG and SSG all 3 cellular constituents appear to develop by 3 months, only SSG had gene expression levels similar to those in controls. The results suggest an explanation for the fibrosis noted in unseeded SIS bladder augmentations and the possible solution using stem cells.

Animals↗
PubMed2005

Transperitoneal versus retroperitoneal laparoscopic partial nephrectomy: patient selection and perioperative outcomes.

PURPOSE: We compared the results of transperitoneal (T) and retroperitoneal (R) approaches to laparoscopic partial nephrectomy (LPN) in regard to perioperative outcomes and technical considerations, thereby, identifying patient selection guidelines for each approach. MATERIALS AND METHODS: The choice of approach was dictated primarily by tumor location, that is TLPN for anterior or lateral lesions and RLPN for posterior or posterolateral lesions. The approaches differed primarily by the hilar control technique. During TLPN en bloc hilar control was achieved with a Satinsky clamp, while during RLPN individual vessel control was obtained with bulldog clamps. RESULTS: In a 3-year period 100 TLPNs and 63 RLPNs were performed for renal tumor. Of posterior tumors 77% were managed by RLPN, whereas 97% of anterior tumors were managed by TLPN. TLPN was associated with significantly larger tumors (3.2 vs 2.5 cm, p <0.001), more caliceal suture repairs (79% vs 57%, p = 0.004), longer ischemia time (31 vs 28 minutes, p = 0.04), longer operative time (3.5 vs 2.9 hours, p <0.001) and longer hospital stay (2.9 vs 2.2 days, p <0.01) than RLPN. Blood loss, perioperative complications, postoperative serum creatinine, analgesic requirements and histological outcomes were comparable between the groups. CONCLUSIONS: We perform TLPN for all anterior or lateral tumors as well as for large or deeply infiltrating posterior tumors that require substantive resection (heminephrectomy). The limited retroperitoneal space makes RLPN technically more challenging but provides superior access to posterior and particularly posteromedial lesions. When feasible, we prefer to perform laparoscopic partial nephrectomy by the transperitoneal approach because of its larger working area and superior instrument angles for intracorporeal renal reconstruction.

Adolescent↗
PubMed2005

Multi-institutional validation study of neural networks to predict duration of stay after laparoscopic radical/simple or partial nephrectomy.

PURPOSE: We developed models to predict post-laparoscopic radical or simple nephrectomy (LapNx) and post-laparoscopic partial nephrectomy (LapPNx) hospital duration of stay (DOS). MATERIALS AND METHODS: We performed a retrospective review (design group) of all 726 patients (July 1997 to April 2004) who underwent LapNx or LapPNx at the Cleveland Clinic Foundation (CCF). Preoperative findings were recorded. Neural network algorithms were designed to predict the DOS before surgery. The models were then tested on a separate 252 patients from 6 different institutions, namely Tulane University Medical School, University of Arkansas for Medical Sciences, Cedars-Sinai Medical Center, University of Iowa, Mayo Clinic at Scottsdale and CCF. RESULTS: In the CCF design groups, the LapNx model accuracy was 73% to 74% and the LapPNx model 73% to 83%. Overall accuracy in the test groups at all 6 institutions was 72% (area under ROC 0.6 to 0.7) for the LapNx model and 52% to 81% (ROC 0.5 to 0.7) for the LapPNx model. CONCLUSIONS: The LapNx model provides 72% accuracy in predicting the DOS at all 6 institutions. The LapPNx model provided fair accuracy only at CCF and Tulane University Medical School. These models may streamline the delivery of care and continued testing will allow for further refinement.

Algorithms↗
PubMed2004

Right donor nephrectomy: a comparison of hand-assisted transperitoneal and retroperitoneal laparoscopic approaches.

BACKGROUND: We compare the anatomic and functional outcomes of right live-donor nephrectomy (LDN) using either a hand-assisted approach (HALDN) or a pure retroperitoneoscopic approach (RLDN) in two institutions. PATIENTS AND METHODS: Data were recorded prospectively in 59 patients undergoing right LDN using either hand-assisted (n=31) or pure retroperitoneoscopic (n=28) approaches. All HALDN cases were performed at the University of Cincinnati, and all RLDN cases were performed at the Cleveland Clinic Foundation. RESULTS: Demographics were similar with respect to age (41.1+/-11.5 vs. 44.5+/-8.5 years) and human leukocyte antigen mismatches (2.7+/-1.8 vs. 2.6+/-1.6). Operative times were longer for HALDN (3.4+/-0.7 vs. 3.0+/-0.7 hours, P <0.04), whereas warm ischemia time was shorter (3:55+/-1:47 vs. 4:55+/-0:55 minutes, P <0.001). Length of renal vein and artery were equivalent (2.4/3.4 vs. 2.3/3.2 cm, P =0.5). Complication rates were similar (10% vs. 7%, P =0.5), including conversion to open surgery (n=1), accessory upper pole artery transection (n=1), and swollen testicle (n=1) in the HALDN group, and a small parenchymal injury (n=1) and a capsular tear (n=1) in the RLDN group. Donor length of stay and convalescence were similar in both groups (43.5+/-14.1 vs. 45.7+/-25.3 hours, P =0.1; convalescence 23.5+/-5.3 vs. 20.2+/-4.1 days, P =0.5). One-week, 1-month, and 1-year serum creatinine levels were equivalent with both approaches. No grafts were lost in either group. CONCLUSIONS: This study confirms that the HALDN and RLDN techniques can provide kidney grafts with equivalent-length vessels and excellent function.

Adult↗
PubMed2004

Right retroperitoneal versus left transperitoneal laparoscopic live donor nephrectomy.

OBJECTIVES: To describe our preferred method of right laparoscopic live donor nephrectomy (LDN) using a retroperitoneoscopic approach to determine the indications for, and overall rate of, right LDN and to compare the donor and recipient early outcomes of right retroperitoneal LDN to those of left transperitoneal LDN in a consecutive single-institution series. METHODS: At our institution, LDN for allotransplantation was performed in 143 consecutive patients. The indications for right LDN (n = 29) included multiple left renal vessels (n = 18), early branching of the left renal artery (n = 1), left renal vein anomaly (n = 2), right renal arterial fibromuscular dysplasia (n = 2), right renal cyst (n = 3), mild right hydronephrosis with delay on renal scan (n = 1), or right nephrolithiasis (n = 2). RESULTS: Right LDN was performed in 29 (20.3%) of 143 patients using a retroperitoneal approach in all but the first case. Right retroperitoneal LDN was associated with decreased blood loss and operative time compared with left transperitoneal LDN. The hospital stay, analgesic use, and donor serum creatinine at discharge were similar in both groups. Despite a statistically significantly increased warm ischemia time and decreased renal vein length, right retroperitoneal LDN was associated with recipient functional outcomes at 5 and 30 days after transplant that were no different from those after left transperitoneal LDN. CONCLUSIONS: Right retroperitoneal laparoscopic LDN provides similar donor and recipient outcomes when compared with the left transperitoneal approach and obviates most of the technical challenges encountered with a right transperitoneal approach.

Adult↗
PubMed2004

Metastatic cancer to the renal pelvis: a novel approach to management.

We describe a novel application of percutaneous renal surgery for the management of an unusual and challenging urologic problem. Two patients with symptomatic, metastatic adenocarcinoma in the renal pelvis were treated with percutaneous resection. The lesion was in a solitary kidney in 1 patient, and was bilateral in the second. Percutaneous resection resulted in complete relief of symptoms and obstruction. Although both patients ultimately died of their primary disease, their quality of life was significantly improved in the interim. Percutaneous resection of renal pelvic tumors is accepted management for select patients with upper tract transitional cell carcinoma. These 2 cases demonstrated both an unusual presentation for metastatic adenocarcinoma and an expanded application for percutaneous renal surgery.

Adenocarcinoma↗
PubMed2004

Ureteropelvic junction obstruction: endourologic relocation of laterally inserting ureters.

PURPOSE: To describe a technique of endourologic management for ureteropelvic junction (UPJ) obstruction associated with lateral insertion of the ureter. PATIENTS AND METHODS: Among 57 patients with primary UPJ obstruction selected to undergo retrograde endopyelotomy, 2 patients (3.5%) demonstrated a nondilated ureter inserting laterally along a hydronephrotic renal pelvis on retrograde pyelography. Using the hot-wire balloon catheter in one and a holmium laser inserted ureteroscopically in one, retrograde endopyelotomy was performed with the incision directed medially in order to marsupialize the ureter into the renal pelvis and to relocate the UPJ to the dependent portion of the medial aspect of the renal pelvis. RESULTS: The hospital stay for both patients was 1 night, and there were no complications. The stent was removed 4 or 6 weeks postoperatively. Intravenous urography 6 weeks thereafter demonstrated relocation of the UPJ to a medial and dependent position, associated with prompt drainage of contrast medium and decreased pelvocaliectasis compared with preoperative studies. Both patients are asymptomatic. CONCLUSIONS: In cases of primary UPJ obstruction associated with lateral insertion of the ureter, the UPJ can be relocated to the medial and dependent portion of the renal pelvis using minimally invasive endourologic techniques. The dictum of performing a endopyelotomy incision laterally does not hold true in all patients and may compromise functional outcomes in cases where the ureteral insertion is nondependent and laterally positioned.

Adult↗
PubMed2004

Laparoscopic radical adrenalectomy with adrenal vein tumor thrombectomy: technical considerations.

PURPOSE: We describe the technique of adrenal vein tumor thrombectomy during laparoscopic radical adrenalectomy for cancer. MATERIALS AND METHODS: During laparoscopic adrenalectomy for a heterogeneous 7 cm left adrenal mass an adrenal vein thrombus was detected intraoperatively. Laparoscopic ultrasonography was used to delineate precisely the tumor thrombus and its extension into the left main renal vein. The left renal artery and vein were transiently controlled with atraumatic vascular clamps. The renal vein was incised and the intact tumor thrombus was removed en bloc with the radical adrenalectomy specimen. The renal vein was suture repaired with 4-zero prolene and the kidney was revascularized. RESULTS: Renal warm ischemia time was 21 minutes, blood loss was 300 cc and operative time was 6.2 hours. Pathological evaluation revealed a 7.5 cm 68 gm adrenal cortical cancer with tumor thrombus. Soft tissue and adrenal vein margins were negative for cancer. CONCLUSIONS: Laparoscopic radical adrenalectomy with en bloc adrenal vein tumor thrombectomy can be exclusively performed intracorporeally, while respecting oncological principles. Essential technical steps include wide margin excision of the adrenal gland, intraoperative ultrasonography, renal vascular control, en bloc tumor thrombectomy and renal venous suture repair in a bloodless field.

Adrenalectomy↗
PubMed2004

Thoracic complications during urological laparoscopy.

PURPOSE: We documented thoracic related complications during urological laparoscopic surgery. MATERIALS AND METHODS: A total of 1129 patients underwent major urological laparoscopic procedures in a 5-year period. Operative reports and postoperative radiographic reports were retrospectively reviewed to identify patients with thoracic related medical and surgical sequelae. Of the patients 619 (55%) underwent at least 1 chest x-ray in the immediate or early postoperative period. In the remaining 510 patients (45%) there was no clinical indication to perform chest x-ray. RESULTS: Of 619 patients undergoing chest x-ray 438 (71%) were completely normal. Medical pulmonary complications, surgical thoracic complications and subclinical, incidentally detected gas collections in the chest were identified in 12.6%, 0.5% and 5.5% of patients, respectively. Medical complications in 12.6% of cases included pulmonary infiltrate/atelectasis in 9.7%, pleural effusion in 4.8% and pulmonary embolus in 0.3%. Surgical complications included symptomatic pneumothorax in 4 patients (0.35%), hemothorax in 1 (0.08%) and chylothorax in 1 (0.08%). Subclinical abnormal thoracic gas collections were radiographically noted in 34 of the 619 patients (5.5%) on chest x-ray, including pneumomediastinum in 19 (3.1%), pneumothorax in 10 (1.6%) and pneumopericardium in 5 (0.8%). Overall 36 of 40 (90%) thoracic surgical complications (3) and subclinical, incidentally detected gas collections (33) occurred during retroperitoneal laparoscopy. Re-intervention was necessary in 6 patients (0.5%), namely pulmonary embolus requiring vena caval filter placement in 3 (0.3%), pneumothorax requiring a chest tube in 2 (0.17%) and hemothorax requiring emergency open thoracotomy in 1 (0.08%). No patient underwent open conversion to complete the initial proposed operation. CONCLUSIONS: Due to its high solubility the expectant management of incidental CO2 pneumothorax, pneumopericardium and pneumomediastinum is recommended initially in the clinically stable patient. Inadvertent diaphragmatic entry can be satisfactorily repaired laparoscopically without open conversion. Although it is rare, surgical thoracic complications are potentially life threatening, requiring prompt identification and management.

Adult↗