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S K Libutti

Publications and source records attributed to S K Libutti.

At least 73 records · Page 4Linked to original sources
PubMed1999

Isolated hepatic perfusion for lapine liver metastases: impact of hyperthermia on permeability of tumor neovasculature.

BACKGROUND: Hyperthermic isolated hepatic perfusion (IHP) has been shown to cause significant regression of advanced unresectable liver metastases in patients. Although there are different agents and treatment modalities used in IHP, the contribution of perfusion hyperthermia is unknown. PURPOSE: A large animal model of unresectable liver metastases and a technical standard for IHP in this model were established. This model was used to assess the effects of hyperthermia on vascular permeability of tumors and normal liver tissue during IHP. METHODS: Sixty-five New Zealand White rabbits were used in a series of experiments. Disseminated liver tumors were established by direct injection of 1 x 10(6) VX-2 cells into the portal vein by laparotomy in anesthetized animals. Several surgical perfusion techniques were explored to determine a reliable and reproducible IHP model. Vascular permeability in tumor versus liver was then assessed with Evan's Blue labeled bovine albumin under normothermic (tissue temperature 36.5 degrees C +/- 0.5 degree C), moderate hyperthermic (39 degrees C +/- 0.5 degree C), or severe hyperthermic (41 degrees C +/- 0.5 degree C) conditions. RESULTS: Tumor model and perfusion techniques were successfully established with inflow through the portal vein and outflow through an isolated segment of the inferior vena cava. A gravity driven perfusion circuit with stable perfusion parameters and complete vascular isolation was used. Vascular permeability was higher in tumor than in normal tissues (P = .03) at all time points during IHP. Hyperthermia resulted in a significant (up to 5-fold) increase in permeability of neovasculature; when severe hyperthermia was used, tumor vascular permeability was increased even more than normal liver permeability (P = .01). CONCLUSIONS: The VX-2/New Zealand White rabbit system can be used as a reproducible large-animal model for IHP of unresectable liver metastases. It can be used to characterize the contribution and mechanism of action of different treatment parameters used in IHP. Hyperthermia preferentially increases vascular permeability in tumors compared with liver tissue in a dose-dependent fashion, thus providing a mechanism for its presumed benefit during isolated organ perfusion.

Animals↗
PubMed1998

A phase I trial of continuous hyperthermic peritoneal perfusion with tumor necrosis factor and cisplatin in the treatment of peritoneal carcinomatosis.

BACKGROUND: Tumor necrosis factor (TNF), hyperthermia, and cisplatin have synergistic cytotoxicity against cancer cells in vitro. This combination may be well suited to the regional treatment of peritoneal tumor spread in patients. Continuous hyperthermic peritoneal perfusion (CHPP) is a technique that allows uniform delivery of cytotoxic agents and heat to the peritoneal surface. A Phase I trial of CHPP with TNF and cisplatin was conducted to define the maximum tolerated dose (MTD) for TNF and cisplatin under moderate hyperthermia in the treatment of peritoneal carcinomatosis. METHODS: Twenty-seven patients with peritoneal carcinomatosis underwent exploratory laparotomy and tumor debulking followed by a 90-minute CHPP with cisplatin (100-350 mg/m2) and TNF (0-0.3 mg/L). Perfusion parameters included a perfusate volume of 3-9 L, a peritoneal temperature of 42-43 degrees C, and a flow rate of 1.5 L/minute. Sodium thiosulfate was administered systemically during and after the perfusion as a cisplatin binding agent. RESULTS: There was no operative or treatment-related mortality in this study. CHPP resulted in a 14-fold higher area under the concentration versus time curve (AUC) for cisplatin in the perfusate compared with plasma, and a 4854-fold higher AUC for TNF. The MTD was defined as 250 mg/m2 cisplatin plus 0.1 mg/L TNF. The dose-limiting toxicity was renal insufficiency. No other systemic toxicity was identified, and no significant regional toxicity was identified. The median time to toleration of a regular diet was 8 days (range, 5-20 days). CONCLUSIONS: The favorable regional pharmacologic profile of the combination of cisplatin and TNF suggests that these agents administered via CHPP warrant further evaluation as prophylaxis against or treatment for peritoneal carcinomatosis.

Adult↗
PubMed1998

Multiple neuroendocrine tumors of the pancreas in von Hippel-Lindau disease patients: histopathological and molecular genetic analysis.

Although pancreatic neuroendocrine tumors (NETs) in von Hippel-Lindau (VHL) disease have been reported, their pathological features have not been characterized. In addition, it is unknown whether alterations of the VHL gene are responsible for pancreatic NET development. To evaluate NETs in VHL patients, we performed histopathological analysis of 30 pancreatic tumors in 14 patients. In addition, DNA from NETs and normal pancreatic tissue from 6 patients with documented germ-line VHL gene mutations was studied for allelic deletions of the second copy of the VHL gene by fluorescence in situ hybridization and polymerase chain reaction-based single-strand conformational polymorphism analysis. Morphologically, the tumors were characterized by solid, trabecular, and/or glandular architecture and prominent stromal collagen bands. Sixty percent of the tumors revealed at least focally clear-cell cytology. All tumors were positive for panendocrine immunohistochemistry markers (chromogranin A and/or synaptophysin); 35% of NETs demonstrated focal positivity for pancreatic polypeptide, somatostatin, insulin, and/or glucagon; and no immunostaining for pancreatic and gastrointestinal hormones was observed in 65% of tumors. Dense core neurosecretory granules were evident by electron microscopic examination, and the clear cells additionally revealed abundant intracytoplasmic lipid. All NETs that were subjected to genetic analysis showed allelic loss of the second copy of the VHL gene. We conclude that multiple, nonfunctional pancreatic NETs occur in VHL patients. Stromal collagen bands and clear-cell morphology are important histological features of VHL-associated NETs. The presence of allelic deletions of the VHL gene in pancreatic NETs provides direct molecular evidence for a role of the gene in their tumorigenesis and establishes NET as an independent tumor type of VHL disease.

Adolescent↗
PubMed1998

Pancreatic neuroendocrine tumors associated with von Hippel Lindau disease: diagnostic and management recommendations.

BACKGROUND: von Hippel Lindau disease (VHL) is an inherited syndrome characterized by tumors of the kidney, adrenal, central nervous system, and pancreas. The incidence and natural history of pancreatic neuroendocrine tumors occurring in VHL are not known. METHODS: From December 1988 through November 1997, 256 patients with VHL were screened with imaging studies, and these data were reviewed from a prospective database. RESULTS: Thirty (12%) of 256 patients had solid pancreatic lesions consistent with neuroendocrine tumors. Fourteen patients underwent resection, and 4 with metastases on imaging studies underwent biopsy only. Of the 14 patients who underwent resection, 11 remain free of disease, 2 have experienced recurrence, and 1 has died of unrelated causes (mean follow-up, 25 months; range, 3 to 73 months). The size of the primary tumor (median, 5 cm; range, 3 to 8 cm) in patients with liver metastases was significantly larger than the size of the primary tumor (median, 2 cm; range, 1 to 5 cm) in patients without liver metastases (P = .0013). CONCLUSIONS: Solid pancreatic lesions were detected in 12% of patients with VHL. Larger primary tumors were associated with liver metastases. Pancreatic imaging to identify neuroendocrine tumors and resection when they reach 2 to 3 cm may prevent the development of hepatic metastases.

Adolescent↗
PubMed1998

Analysis of factors associated with long-term (five or more years) cure in patients undergoing operation for Zollinger-Ellison syndrome.

BACKGROUND: Only 30% to 40% of patients with Zollinger-Ellison syndrome (ZES) undergoing operation with curative intent have biochemical cures. The purpose of this analysis was to identify perioperative factors associated with long-term (> or = 5 years) biochemical cures. METHODS: From December 1981 to September 1997, 128 patients with potentially curable ZES underwent 152 abdominal explorations with resection of all identifiable disease. Of these, 31 outcomes were identified with documented cures at > or = 5 years from operation and were compared with outcomes of 110 patients who were not cured. Univariate and multivariate statistical analyses were performed. RESULTS: The results of a normal immediate postoperative fasting serum gastrin and secretin stimulation test were significantly and independently correlated with 5-year cure (P2 = .005 and .0099, respectively). A diagnosis of multiple endocrine neoplasia type 1 was significantly inversely correlated with cure on univariate analysis (P2 = .027). Gender, age, duration of symptoms, results of diagnostic tests, or results of imaging studies did not correlate with outcome. CONCLUSIONS: All patients with sporadic potentially curable ZES should undergo exploration because outcome is not associated with preoperative tests. Only 5% of patients with ZES and multiple endocrine neoplasia type 1 were cured at 5 years. A normal fasting serum gastrin or secretin stimulation value value immediately postoperatively provides important prognostic information.

Female↗
PubMed1998

Operative management of islet-cell tumors arising in the head of the pancreas.

BACKGROUND: Pancreatic islet cell tumors (ICTs) can be treated by enucleation or pancreatic resection. We reviewed our experience with ICTs in the head of the pancreas to define indications for enucleation versus pancreaticoduodenectomy. METHODS: Between January 1982 and December 1997, 48 patients underwent surgical resection for presumed ICTs of the pancreatic head. Of these, 18 were found on pathologic examination to be disease in a lymph node. Thirty patients had 32 true pancreatic head ICTs. We reviewed the operative results and postoperative courses in these patients. RESULTS: Mean diameter of the ICTs was 15 mm. Twenty-seven patients (90%) underwent successful enucleations. Three patients failed enucleation and underwent pancreaticoduodenectomy. There was no operative mortality. The median time to regular diet was 7 days. The median time to removal of all drains was 22 days. The most common complication was pancreatic fistula (15%). No patient required reoperation for treatment of a fistula. CONCLUSION: Most ICTs of the pancreatic head can be removed with enucleation, preserving pancreatic tissue and avoiding the morbidity of pancreaticoduodenectomy. The primary indication for pancreaticoduodenectomy is not the size of the lesion but its proximity to the pancreatic duct.

Adolescent↗
PubMed1998

Hypocalcemic stimulation and nonselective venous sampling for localizing parathyroid adenomas: work in progress.

PURPOSE: To evaluate whether the release of parathyroid hormone (PTH) from parathyroid tumors during selective parathyroid arteriography can help localize the tumors. MATERIALS AND METHODS: In 20 patients (six men, 14 women; age range, 24-72 years) with parathyroid tumors undergoing parathyroid arteriography after failed surgery, serial measurements of PTH were obtained during selective arteriography with nonionic contrast material. PTH levels were measured in the superior vena cava (SVC) before and at varying times from 20 to 120 seconds after arteriography. RESULTS: A 1.4-fold increase in the PTH level of the postarteriographic SVC samples enabled correct prediction of the site of adenoma in 13 of the 20 patients (65%). Of nine patients with positive arteriograms, eight had positive results of postarteriographic sampling. Of 11 patients with negative arteriograms, five had positive results of postarteriographic sampling. CONCLUSION: Sampling the SVC for PTH gradients after selective parathyroid arteriography correctly indicated the site of the adenoma in 13 of 20 patients (65%).

Adenoma↗
PubMed1998

Isolated hepatic perfusion with tumor necrosis factor and melphalan for unresectable cancers confined to the liver.

PURPOSE: To evaluate the efficacy and systemic and regional toxicities of hyperthermic isolated hepatic perfusion (IHP) using tumor necrosis factor (TNF) and melphalan for the treatment of unresectable primary or metastatic cancers confined to the liver. PATIENTS AND METHODS: Thirty-four patients (18 men and 16 women; mean age, 49 years) underwent a 60-minute hyperthermic (39.5 degrees to 40.0 degrees C) IHP performed by laparotomy that used TNF 1.0 mg and melphalan 1.5 mg/kg. Perfusion inflow was through the gastroduodenal artery and outflow was from a cannula positioned in an isolated segment of retrohepatic inferior vena cava (IVC). Infrahepatic IVC and portal venous blood flow were shunted to the axillary vein using an external venoveno bypass circuit. Complete vascular isolation of the liver was confirmed by an I-131-labelled human serum albumin monitoring technique. RESULTS: There was no operative mortality. Seventy-five percent of patients had reversible grade III or IV (National Cancer Institute Common Toxicity Criteria) hepatic toxicity with one treatment-related mortality (3%) because of hepatic venoocclusive disease. In 33 assessable patients, the overall response rate was 75% (complete response, one patient [3%]; partial response, 26 patients [72%]). With a median potential follow-up of 15 months, the mean duration of response was 9 months (range, 2 to 30 months). CONCLUSION: IHP with TNF and melphalan results in significant regression of bulky hepatic cancers confined to the liver in the majority of patients. Based on these initial results, further refinement of this treatment technique is warranted; perhaps by the combination of IHP with other regional treatment strategies to provide long-term control of unresectable cancers confined to liver.

Adult↗
PubMed1998

Augmented capillary leak during isolated hepatic perfusion (IHP) occurs via tumor necrosis factor-independent mechanisms.

Isolated organ perfusion of the liver or extremity with tumor necrosis factor (TNF) and melphalan results in regression of bulky tumors in the majority of patients. The efficacy of TNF in this setting is not known, although data suggest that it may exert antitumor effects primarily on tumor-associated neovasculature. We studied the effects of TNF on capillary leak in liver and tumor tissue during isolated hepatic perfusion (IHP) with melphalan. Twenty-seven patients with unresectable cancer confined to the liver underwent a 60-min hyperthermic IHP using 1.5 mg/kg melphalan alone (n = 7) or with 1.0 mg of TNF (n = 20). Complete vascular isolation was confirmed in all patients using an intraoperative leak monitoring I-131 radiolabeled albumin technique. Samples of tumor and liver were collected just prior to and immediately after IHP. There was no difference in I-131 radiolabeled cpm/g of tissue (cpm) in liver versus tumor at baseline (P2 = 0.44). After IHP, I-131 albumin cpm were higher in tumor versus liver (10,999 +/- 1,976 versus 3,821 +/- 780, respectively; P2 < 0.005). However, I-131 albumin cpm in tumor were not effected by TNF (11,636 +/- 2,518 with TNF versus 9,180 +/- 2,674 without TNF; P2 = 0.59). TNF did not affect melphalan concentrations in tumor (1,883 +/- 540 ng/g versus 1,854 +/- 861 ng/g without TNF; P2 = 0.9). Capillary leak, as reflected by diffusion of I-131 radiolabeled albumin into the interstitial space, is comparable in liver and tumor before IHP but is significantly higher in tumor after IHP. The increased diffusion in the capillary tumor bed must occur through TNF-independent mechanisms such as intrinsic features of tumor neovasculature, hyperthermia, or other unrecognized perfusion-related factors. These data indicate that TNF must continue to be critically evaluated in clinical trials before it is routinely used with melphalan in isolated organ perfusion.

Adult↗
PubMed1997

Isolated limb reperfusion with tumor necrosis factor and melphalan in patients with extremity melanoma after failure of isolated limb perfusion with chemotherapeutics.

BACKGROUND: This retrospective study evaluated the benefit of using tumor necrosis factor (TNF) and melphalan administered via an isolated limb perfusion (ILP) in a series of patients with metastatic melanoma who failed initial ILP with chemotherapeutics. METHODS: Seventeen patients with extremity melanoma who underwent prior ILP with conventional chemotherapeutics (10 with melphalan; 4 with platinum; 2 with platinum, dacarbazine, thiotepa, actinomycin D, and nitrogen mustard; and 1 with thiotepa, actinomycin D, and nitrogen mustard) and had local recurrences were treated with a 90-minute isolated hyperthermic limb reperfusion with melphalan (10 mg/L limb volume) plus TNF (2-6 mg). Five prior ILPs were adjuvant and 12 were therapeutic. RESULTS: Reperfusion was associated with an overall 94% response rate and a 65% complete response (CR) rate. Of the patients who failed an initial ILP with melphalan alone the overall response rate was 90% after the reperfusion with TNF and melphalan. In patients who failed an initial ILP with agents other than melphalan the CR rate was 100% after ILP with TNF and melphalan. TNF/melphalan isolated limb reperfusion was found to be more effective in terms of CR after initial ILP regimens that did not utilize melphalan (100% CR after nonmelphalan ILP vs. 50% CR after melphalan ILP [P = 0.04]). Regional toxicity was comprised of mild skin blistering and peeling in 47% of patients. One patient developed Grade 3 (based on National Cancer Institute Common Toxicity Criteria) skin necrosis, and one developed Grade 5 muscle and nerve toxicity, requiring an amputation. CONCLUSIONS: Isolated limb reperfusion with TNF and melphalan can be performed safely with response rates similar to those of other trials of single perfusions. Repeat ILP using TNF and melphalan in patients with melanoma who have failed prior ILP with chemotherapeutics is justified. The utility of TNF (vs. melphalan alone) will be defined in ongoing Phase III trials.

Adult↗
PubMed1997

The role of thyroid resection during reoperation for persistent or recurrent hyperparathyroidism.

BACKGROUND: The role of "blind" thyroid lobectomy in the surgical management of patients with persistent or recurrent primary hyperparathyroidism is not known. We reviewed our experience with reoperation for hyperparathyroidism to determine the utility of blind thyroid resection in this setting. METHODS: From 1982 to 1995, 269 patients underwent reoperation for hyperparathyroidism at our institution. All patients had biochemical confirmation of hyperparathyroidism and underwent noninvasive and if necessary invasive localization studies. Patients who underwent thyroid lobectomy in an attempt to extirpate the hyperfunctioning parathyroid gland form the basis of this report. RESULTS: Thirty-two of 269 patients (12%) underwent thyroid lobectomy to remove a parathyroid gland. Intrathyroidal parathyroids were confirmed in 19 of 32 patients (59%). In 18 of 19 patients (94%), preoperative or intraoperative ultrasonography correctly identified an intrathyroidal lesion suspicious or a parathyroid. Only 1 of 6 patients (17%) undergoing a blind thyroidectomy had an intrathyroidal gland identified. Ultrasonography had a sensitivity of 95% and a negative predictive value of 99.5% in detecting an intrathyroidal parathyroid gland. CONCLUSIONS: The prevalence of an intrathyroidal parathyroid gland in our series is low (19 of 269, 7%). Ultrasonography can be used reliably to select patients for thyroid resection, reducing the need to perform a blind thyroid lobectomy and avoiding the potential morbidity of thyroid resection in this clinical setting.

Adolescent↗
PubMed1997

Intraarterial calcium stimulation and intraoperative ultrasonography in the localization and resection of insulinomas.

BACKGROUND: Standard imaging studies (computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, ultrasonography, and angiography) correctly localize insulinomas in less than 50% of patients and provide no information about the feasibility of enucleation based on proximity of tumor to pancreatic duct. We reviewed our experience with intraarterial calcium stimulation (Ca-Stim) and intraoperative ultrasonography (IOUS) to localize and guide management of insulinomas. METHODS: Thirty-six patients (14 men, 22 women, median age 44 years) with insulinomas were treated between August 1989 and June 1996. Preoperative imaging studies were obtained. Patients underwent abdominal exploration with IOUS. Fourteen were evaluated by a surgeon blinded to preoperative imaging results. RESULTS: Tumors (4 to 50 mm) were resected by enucleation (67%) or partial pancreatectomy (33%); all were cured. Sensitivities of computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, ultrasonography, angiography, and Ca-Stim in localizing insulinomas were 24%, 45%, 17%, 13%, 43%, and 94%, respectively. Tumors were identified by blinded surgical exploration with IOUS in 12 of 14 patients (86%). CONCLUSIONS: All insulinomas were identified before operation; however sensitivity of individual noninvasive tests was low (less than 50%). In contrast, Ca-Stim was correct in 94% of cases, thus allowing a focused pancreatic exploration and obviating use of blind distal pancreatectomy. IOUS can then be used to guide safe enucleation.

Adolescent↗
PubMed1997

Advances in the early detection, diagnosis, and staging of pancreatic cancer.

Pancreatic cancer is an aggressive disease with a dismal prognosis. It has long been regarded as one of the most difficult cancers to accurately diagnose and stage preoperatively. The purpose of this review is to provide an update of the state-of-the-art for early detection, diagnosis, and staging of pancreatic cancer. These methods include spiral CT scans, magnetic resonance imaging, positron emission tomography (PET) imaging, laparoscopy, endoscopic ultrasound, CA 19-9 serology, fine needle aspiration cytology, ERCP brush cytology, and screening for p53 and ras oncogenes. These advanced techniques should help us to detect pancreatic cancers in high-risk populations at a curative stage and to decrease pancreaticoduodenectomies for benign disease which could otherwise be treated with less morbid procedures. In addition, these tests will help reliably diagnose pancreatic cancer preoperatively.

Animals↗
PubMed1996

Effects of diode laser welding with dye-enhanced glue on tensile strength of sutures commonly used in urology.

BACKGROUND AND OBJECTIVE: Tissue welding using laser-activated protein solders may soon become an alternative to sutured tissue approximation. In most cases, approximating sutures are used both to align tissue edges and provide added tensile strength. Collateral thermal injury, however, may cause disruption of tissue alignment and weaken the tensile strength of sutures. The objective of this study was to evaluate the effect of laser welding on the tensile strength of suture materials used in urologic surgery. STUDY DESIGN/MATERIAL AND METHODS: Eleven types of sutures were exposed to diode laser energy (power density = 15.9 W/cm2) for 10, 30, and 60 seconds. Each suture was compared with and without the addition of dye-enhanced albumin-based solder. After exposure, each suture material was strained (2"/min) until ultimate breakage on a tensometer and compared to untreated sutures using ANOVA. RESULTS: The strength of undyed sutures were not significantly affected; however, violet and green-dyed sutures were in general weakened by laser exposure in the presence of dye-enhanced glue. Laser activation of the smallest caliber, dyed sutures (7-0) in the presence of glue caused the most significant loss of tensile strength of all sutures tested. CONCLUSION: These results indicate that the thermal effects of laser welding using our technique decrease the tensile strength of dyed sutures. A thermally resistant suture material (undyed or clear) may prevent disruption of wounds closed by laser welding techniques.

Adhesives↗
PubMed1996

Laser welding with albumin-based solder: experimental full-tubed skin graft urethroplasty.

BACKGROUND AND OBJECTIVES: Fistula and stricture formation at the site of sutured anastomoses are frequent complications of major urethroplasty. We performed urethroplasty using laser-welded skin tube grafts in the hope that in addition to being free of suture holes, grafts would be as strong as or stronger than sutured controls. STUDY DESIGN/MATERIAL AND METHODS: Scrotal skin was harvested from each of 11 rabbits and fashioned into tubes 3-4 cm in length using either conventional suture techniques or laser welding. Welding was performed using an 808-nm diode laser and a dye-enhanced solder composed of albumin and sodium hyaluronate. Laser power density was 15.9 watts/cm2. For each graft, leak pressure, and urethroplasty time (tube creation and anastomosis to native urethra) were measured. RESULTS: Urethroplasty time was significantly shorter and initial leak pressures were seven times greater in the laser-welded group. CONCLUSIONS: The near-uniform occurrence of strictures in both groups suggests that the rabbit is not an ideal model for free tube graft urethroplasty. However, our data indicate that laser welding with albumin-based solder, when used in the appropriate setting, may offer the potential for the rapid creation of watertight grafts in reconstructive urology.

Aluminum↗
PubMed1996

A novel tumor-derived mediator that sensitizes cytokine-resistant tumors to tumor necrosis factor.

Therapeutic successes following treatment of murine tumors with tumor necrosis factor-alpha (TNF) have not been easily applied to clinical oncology because the concentrations of TNF required in humans induces systemic toxicity. This has led us to identify mediators which could sensitize tumors to the effects of TNF, permitting administration of lower doses and possible realization of the therapeutic potential of this cytokine. Our study reports the ability of a novel cytokine, endothelial-monocyte-activating polypeptide II (EMAP II), to sensitize initially resistant murine and human tumors to TNF-induced regression employing a murine model. Recombinant (r) EMAP II was purified from Escherichia coli transformed with a plasmid expressing mature EMAP II. The B16 melanoma, raised in C57BL/6 mice, or a human fibrosarcoma (HT-1080), grown in immunocompromised mice, was injected intratumorally with either vehicle or rEMAP II/heat-treated EMAP II (50-100 micrograms) followed by systemic TNF/heat-treated TNF (5 micrograms) and assessed for tumor volume, hemorrhage, and histologic appearance. Both the B16 melanoma and the HT-1080 human fibrosarcoma underwent thrombohemorrhagic and acute inflammatory changes concomitant with regression or significantly slowed growth after administration of intratumor EMAP II followed by systemic TNF. Omission or inactivation of either cytokine abrogated this effect. These results demonstrate that local treatment of certain tumors with EMAP II results in enhanced susceptibility to TNF-mediated induction of thrombohemorrhage and regression.

Animals↗
PubMed1995

Sutureless rabbit bladder mucosa patch graft urethroplasty using diode laser and solder.

Fistula and strictures at the site of sutured anastomoses are frequent complications of major urethroplasty. We harvested bladder mucosa in 26 rabbits to repair large defects in the proximal urethra using laser-activated solder in the hope that such a repair would be stronger, faster to create and avoid common complications seen with conventional repair. Large oval defects were created in the proximal urethra in all animals undergoing urethroplasty. Twelve animals underwent bladder mucosa graft closure via diode (808 nm.) laser activation of an albumin-based solder (50% were suture-free). Fourteen additional animals underwent closure with 7-zero polydiaxanone suture (controls). Leak pressure and time of repair were recorded for each graft. Additional sections of bladder mucosa were harvested, transected and repaired by laser welding to determine tensile strength. In both groups, radiography, urethroscopy and clinical course were evaluated for as much as 6 weeks postoperatively. Urethroplasty time was significantly (p < 0.01) shorter for the laser group (13.8 +/- 2.5 minutes) than for the sutured repair group (24.0 +/- 5.3 minutes). Initial leak pressures for the lasered grafts averaged at least 4 times those of sutured grafts (p < 0.01). The tensile strength for lasered bladder mucosa was 3.16 +/- 1.12 kg./cm.2 Early retrograde urethrograms (RUG) performed at 7 days (n = 5) revealed urinary extravasation and fistula formation in 2 control animals compared with a normal urethral appearance in 3 lasered repairs. Early retrograde urethrograms performed at 21 days (n = 21) demonstrated smooth-walled urethras with no evidence of fistula, stricture, or urinary extravasation in the lasered group; varying degrees of reactive mucosal proliferation were seen in the controls. Urethroscopy confirmed these observations. At 6 weeks, histologic examination confirmed the presence of viable graft in all animals. We conclude that bladder mucosa patch graft urethroplasty using diode laser welding and albumin-based solder is an attractive alternative to conventional methods.

Animals↗