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Biomedical subjects

Benjamin R Lee

Publications and source records attributed to Benjamin R Lee.

29 records · Page 2Linked to original sources
PubMed2003

Immune response to laparoscopic bowel injury.

BACKGROUND AND PURPOSE: Laparoscopic bowel injuries are rare but potentially fatal if recognition is delayed. Unlike the situation after open surgery, patients with unrecognized bowel injury after laparoscopy do not present with the typical "acute surgical abdomen." We investigated monocyte, neutrophil, and lymphocyte apoptosis as indicators of the immune response and whether this response is stimulated or suppressed by laparoscopic bowel injury compared with bowel injury induced during open surgery. MATERIALS AND METHODS: After an animal protocol was approved, laparoscopy was performed in a rabbit model. A total of 44 animals were divided into four groups of 11 rabbits each. Laparoscopic bowel injury was created using 30-W electrocautery at 0 (control), 1, and 5 hours after induction of pneumoperitoneum. Bowel injury was created in the fourth group during open laparotomy. Animals were euthanized at 0, 1 day, 1 week, or 2 weeks after surgery. Apoptosis was assessed by staining the nuclei of blood cells with H-33342 dye. RESULTS: At 1 week, neutrophil, monocyte, and lymphocyte apoptosis levels were 2.4- to 5-fold lower after laparoscopy (1-hour pneumoperitoneum) compared with open surgery. However, at 2 weeks, the percentage of apoptosis had equalized in the two groups. Interestingly, with longer laparoscopic procedures (5 hours), the percentage of apoptosis at 0 and 1 day more closely approached that seen after open surgery. At 2 weeks, there was a significant difference in apoptosis levels in all cell types between the experimental groups compared with controls (P < 0.001). No animals undergoing a 5-hour open procedure survived to 2 weeks after bowel injury. CONCLUSIONS: Open surgery resulted in a significant increase in programmed cell death compared with controls in the immediate postoperative period following bowel injury. Laparoscopic surgery produced a delayed response and after 2 weeks with bowel perforation approached open surgery levels. The difference in the degree of cellular death may be secondary to a smaller degree of stimulation of the immune response in laparoscopic surgery.

Analysis of Variance↗
PubMed2003

Efficacy and morbidity of therapeutic renal embolization in the spectrum of urologic disease.

PURPOSE: We report the largest series of renal embolizations performed for a variety of indications. PATIENTS AND METHODS: A retrospective analysis was performed on embolizations performed in our institution from 1997 to 2002 encompassing 36 patients who underwent 44 procedures. RESULTS: Embolization was successful on the first attempt in 87% of the patients. A second embolization was performed in four of the five unsuccessful cases, three successfully, increasing the success rate to 95%. The mean postoperative narcotic use was 27.2 mg of morphine equivalent, and 10 mg or less was required by 45% of the patients. In the 14 patients who had not also undergone a surgical procedure, the mean narcotic use was 21 mg, and 64% required 10 mg or less. Only 15% of the patients developed fever, which resolved within 2 days in all cases. Leukocytosis was seen in 47%. Follow-up creatinine and hypertension information was available in 16 and 18 patients, respectively. After a mean follow-up of 269 days, only one patient had a clinically significant rise in the creatinine concentration. After a mean follow-up of 496 days, two patients had new-onset hypertension. There was no statistically significant difference in the success rate, narcotic use, complications, creatinine concentrations, or the likelihood of fever, leukocytosis, or hypertension according to the indication for embolization or the agent used. Use of a microcatheter was associated with less parenchymal loss, and decreased parenchymal loss was associated with a significant reduction of narcotic use. CONCLUSIONS: Renal embolization is a highly effective and well-tolerated procedure in a variety of urologic conditions. The indications and material used did not have a significant effect on the outcome. Reducing parenchymal loss can significantly reduce morbidity.

Analgesics↗
PubMed2003

Residual air persists in the renal collecting system following percutaneous nephrolithotomy.

OBJECTIVES: To determine the presence or absence of air in the renal collecting system 48 hours following percutaneous nephrolithotomy (PCNL). METHODS: The study was based on a review of the records of the last 100 consecutive patients undergoing PCNL for stone extraction. Two urologists and a uroradiologist reviewed post-PCNL nephrostogram films and determined the presence or absence of air in the urinary tract. RESULTS: Nephrostography was routinely performed 48 hours after PCNL, and all films of the 100 patients were reviewed. Gas was detected in 98 (98%) of the 100 cases that appeared as gas pyelograms outlining the renal calyces. Of the 98 cases, 33 (34%) demonstrated gas in the upper calyx, 10 (10%) in the middle calyx, 12 (13%) in the lower calyx, and 43 (44%) in more than one calyx. Gas was not detected in the renal parenchyma or perirenal areas. CONCLUSIONS: Gas is present within the renal collecting system 48 hours after a percutaneous procedure. Prospective studies should be performed to document the amount of time needed for complete resolution of gas from the collecting system.

Adult↗
PubMed2003

Optimal lesion assessment following acute radio frequency ablation of porcine kidney: cellular viability or histopathology?

PURPOSE: Radio frequency ablation (RFA) has been used as a minimally invasive alternative to nephrectomy for small renal tumors. Questions have arisen regarding the accuracy of cell viability determination on standard hematoxylin and eosin (H & E) staining. We investigated and compared the histological characteristics of RF ablated renal tissue using nicotinamide adenine dinucleotide (NADH) and H & E staining. MATERIALS AND METHODS: Ten porcine kidneys underwent laparoscopic RFA of the upper and lower poles using a 2 (8) or 3 cm (2) protocol with 2 cycles of 90 W, target temperature 105C and treatment time 5.5 minutes per cycle. Following tract ablation the kidneys were immediately harvested, gross lesion size was measured and tissue was processed for standard H & E and NADH staining. RESULTS: H & E staining of ablated tissue revealed a number of alterations in renal tubular histology. However, all of these findings were focal with areas of parenchyma that appeared well preserved. Corresponding areas on NADH processed sections showed the complete absence of staining, indicating the lack of cellular viability. There were no skip areas noted on NADH processed sections and treated portions demonstrated a well demarcated border of ablation. CONCLUSIONS: While RFA produces discernible histological changes acutely on H & E, these alterations are variable and patchy, and they alternate with areas of well preserved tissue. Therefore, NADH staining should always be used to assess and verify cellular death in RFA lesions. In this study no skip areas of viable cells were noted within areas of ablated tissue on NADH staining.

Animals↗
PubMed2003

Laparoscopic total and partial nephrectomy-the new standard?

Laparoscopic radical nephrectomy has been shown in long-term follow-up to provide shorter patient hospitalization and effective cancer control with no significant difference in survival compared with open radical nephrectomy. The major technical issue for success of laparoscopic partial nephrectomy is hemostatic control, and several techniques have been developed to improve control. Laparoscopic partial nephrectomy continues to evolve along two therapeutic technical avenues: hilar clamping with ischemia versus no hilar clamping. The benefits of laparoscopy for the kidney have clearly been demonstrated in terms of less pain, decreased convalescence, and decreased narcotic requirements. With short-term outcomes demonstrating laparoscopic partial nephrectomy as an efficacious procedure, the role of laparoscopic partial nephrectomy should continue to increase.

Journal Article↗
PubMed2002

Comparison of robotic versus laparoscopic skills: is there a difference in the learning curve?

OBJECTIVES: To evaluate the learning curve between robot-assisted and manual laparoscopic suturing, as well as to assess other skills. Laparoscopic reconstructive procedures have been limited by instrumentation, small working spaces, and fixed angles at the trocar level to place sutures. Robot-assisted laparoscopic suture placement may provide one means of increasing dexterity and facilitating laparoscopic reconstructive procedures. METHODS: Eight physicians participated in this study. A series of five trials were performed to assess dexterity (task 1) and free-hand suturing (task 2). Each task was performed using robot-assisted and manual laparoscopy. The participants were categorized as novice and experienced laparoscopists. Task 1 involved passing sutures through the eye of seven needles positioned 1 cm apart in a P configuration. Task 2 involved tying one surgeon's knot, followed by two subsequent knots. RESULTS: The average time for trials 1 and 5 of task 1, robot-assisted laparoscopy, was 242.6 and 101.8 seconds, respectively (P <0.001). Both groups demonstrated a statistically significant difference (P <0.001) between the first and last trial. The average time for trials 1 and 5 of task 1, manual laparoscopy, was 205.3 and 169 seconds, respectively. The differences in the learning curves for robot-assisted and manual laparoscopy were statistically significant in favor of robotic assistance. Manual laparoscopic suturing did not demonstrate as much of a difference for the experienced surgeon. Overall, the difference in improvement between robot-assisted and manual laparoscopy was not statistically significant. CONCLUSIONS: Robot-assisted laparoscopic allows suturing and dexterity skills to be performed quicker than does manual laparoscopy.

Clinical Competence↗
PubMed2002

Role of acellular collagen matrix surgisis in the endoscopic management of ureteropelvic junction obstruction.

PURPOSE: To investigate the role of acellular collagen matrix (Surgisis during endopyelotomy. MATERIALS AND METHODS: Nine female pigs (25-35 kg) were enrolled in our protocol. The pigs were categorized as follows. Group I (N = 3) had endopyelotomy + insertion of SIS, Group II (N = 3) creation of UPJ stricture + endopyelotomy + insertion of SIS, and Group III (N = 3) Davis intubated ureterotomy using SIS. The contralateral side served as a control for each group (one pig in each group). In three pigs (two in Group III and one in Group II), Surgisis was treated with India ink prior to insertion at the endopyelotomy site. An endopyelotomy stent (14/8 F x 24 cm) was used to stent the ureteropelvic junction (UPJ) for 4 weeks. Four weeks after the stent was removed, laparoscopic nephroureterectomy was performed, and the animals were euthanized. Histopathologic analysis of the Surgisis-regenerated segment of the UPJ was performed using hematoxylin and eosin, reticular (collagen), smooth muscle actin, and S-100 (nerve) stains. RESULTS: All animals tolerated the procedure. The mean operative time was 162 minutes. One pig (Group II) developed pyonephrosis; one pig (Group III) developed significant ascites and was sacrificed 2 week before the end of the experiment. Histopathologic analysis showed complete epithelializaton at 8 weeks. Reticular stain demonstrated abundant collagen matrix in the submucosa. Smooth muscle staining revealed myofibroblastic proliferation within the SIS-regenerated tissue adjacent to disorganized smooth muscle cells. India ink-stained SIS-regenerated tissue did not show smooth muscle cells. The S-100 stain did not demonstrate neurons at 8 weeks; however, in three pigs, peristaltic activity was noted across the UPJ. CONCLUSION: The use of acellular collagen matrix in the endoscopic management of UPJ obstruction is a promising technique. The abundance of myofibroblasts and absence of abundant smooth muscle regeneration indicates a need to investigate the role of growth factors in SIS regeneration of host tissue.

Actins↗
PubMedDate not supplied

Laparoscopic nephroureterectomy with bladder-cuff resection: techniques and outcomes.

Advancements in minimally invasive instrumentation and technique have provided the impetus to performing urologic procedures with reduced perioperative morbidity, shorter hospital stays, and, most importantly, efficacious oncologic results. At multiple centers of excellence, laparoscopic nephroureterectomy (LNU) has evolved into a new standard for the management of upper-tract transitional-cell carcinoma (TCC) that is not amenable to endoscopic resection. An LNU may be performed via a transperitoneal or retroperitoneal approach together with excision of the distal ureter and a bladder cuff. Analysis of present-day studies comparing LNU with open techniques demonstrates equivalent oncologic outcomes. In addition, those patients undergoing LNU fare better than their counterparts having open surgery with respect to hospital stay, analgesic requirements, and convalescence. With multiple options for excision of a cuff of bladder, a consensus has not been established. However, LNU has emerged as the new standard of care for the treatment of upper- tract TCC. Review of the techniques and outcomes of LNU from the minimally invasive urology community are described.

Carcinoma, Transitional Cell↗
PubMedDate not supplied

Hand-assisted laparoscopic renal surgery: current trends and applications.

OBJECTIVE: Hand-assisted laparoscopic surgery has recently been introduced in order to help ease the learning process associated with standard laparoscopic surgery. It has various urological applications in the management of malignant and benign disease of the kidney. The purpose of this study is to review the applications and the success rate associated with hand-assisted laparoscopic surgery. METHODS: A comprehensive literature review of hand-assisted urological surgery was performed using MEDLINE search. RESULTS: Hand-assisted laparoscopic nephrectomy has been performed for benign and malignant disease, donor renal transplant, and nephron sparing surgery with good success. Patients who undergo the hand-assisted procedure seem to have less perioperative morbidity than those who undergo an open procedure. This approach minimized the warm-ischemia time in renal transplantation. CONCLUSION: Hand-assisted nephrectomy is a useful tool facilitating the learning process in laparoscopy.

Carcinoma, Renal Cell↗
PubMedDate not supplied

Laparoscopic total and partial nephrectomy.

Laparoscopic radical nephrectomy has established its role as a standard of care for the management of renal neoplasms. Long term follow-up has demonstrated laparoscopic radical nephrectomy has shorter patient hospitalization and effective cancer control, with no significant difference in survival compared with open radical nephrectomy. For renal masses less than 4cm, partial nephrectomy is indicated for patients with a solitary kidney or who demonstrate impairment of contralateral renal function. The major technical issue for success of laparoscopic partial nephrectomy is bleeding control and several techniques have been developed to achieve better hemostatic control. Development of new laparoscopic techniques for partial nephrectomy can be divided into 2 categories: hilar control and warm ischemia vs. no hilar control. Development of a laparoscopic Satinsky clamp has achieved en bloc control of the renal hilum in order to allow cold knife excision of the mass, with laparoscopic repair of the collecting system, if needed. Combination of laparoscopic partial nephrectomy with ablative techniques has achieved successful excision of renal masses with adequate hemostasis without hilar clamping. Other techniques without hilar control have been investigated and included the use of a microwave tissue coagulator. In conclusion, laparoscopic radical nephrectomy for renal cell carcinoma has clearly demonstrated low morbidity and equivalent cancer control. The rates for local recurrences and metastatic spread are low and actuarial survival high. Furthermore, laparoscopic partial nephrectomy has demonstrated to be technically feasible, with low morbidity. With short term outcomes demonstrating laparoscopic partial nephrectomy as an efficacious procedure, the role of laparoscopic partial nephrectomy should continue to increase.

Journal Article↗