Biomedical subjects

S R Klein

Publications and source records attributed to S R Klein.

At least 73 records · Page 4Linked to original sources

PubMed1988

Thermal studies of in-vivo vascular tissue fusion by argon laser.

There are conflicting opinions regarding the mechanism of welding or fusion of vascular tissue by lasers. In this study, we measured the effects of saline irrigation on tissue temperature and fusion produced by argon laser welding of eight femoral and four carotid arteriovenous fistulas. Temperatures were continuously recorded using a digital thermographic camera. Forty 1-cm. welds were performed using powers of 0.50 (n = 24), 0.75 (n = 8), and 1.00 (n = 8) watt (W), with an energy fluence of 1100 J/cm2 per 1 cm segment, and cooling of the anastomotic site by saline irrigation (3 ml/minute). The "success" of fusions was determined by testing integrity of the repairs by exposure to blood flow. At 0.50 and 0.75 W, successful welds were formed when the temperatures were 44.2 +/- 1.6 (n = 28) and 55.0 +/- 3.6 degrees C (n = 20), with maximum temperatures of 47.9 and 59.9 degrees C respectively. At 1 W, the tissue was desiccated and the welds disrupted when exposed to blood flow with temperatures measured at 63.7 +/- 10.0 degrees C (n = 22) and maximum of 88.0 degrees C. Eight welds were also attempted without saline irrigation at 0.25 (n = 4) and 0.50 W (n = 4). At 0.25 W, tissue fusion was achieved but disrupted when exposed to intraluminal pressures with temperatures 50.3 +/- 2.0 degrees C (n = 10) and maximum of 52.6 degrees C. At 0.50 W, the fusion failed after only minimal exposure to the laser energy because of tissue drying and retraction with temperatures measured at greater than 125 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Clinical use of nonautologous fibrin glue.

Nonautologous, highly concentrated human fibrinogen and clotting factors were used in the form of fibrin glue to treat three patients with varied surgical problems that were resistant to conventional treatment. Fibrin glue was used to occlude longstanding enterocutaneous fistulae, control liver hemorrhage in an alcoholic patient with coagulopathy, and perform a splenorrhaphy, following a gunshot wound to the spleen. Fibrin glue is effective in establishing hemostasis and sealing tissues; its use is a helpful adjunct in the care of surgical patients.

Adult↗

PubMed1988

Preoperative splenic artery occlusion as an adjunct for high risk splenectomy.

High risk splenectomy is often encountered in cases of hypersplenism with massive splenomegaly (10 times usual weight of 150-200 g) resulting from myelophthisic processes. Intra-operative ligation of the splenic artery through the lesser sac is a technically useful method of gaining vascular control prior to mobilizing the challenging spleen. However, a massive or inaccessible spleen imposes mechanical limitations during surgery and may be complicated by torrential intra-operative hemorrhage in the setting of severe thrombocytopenia refractile to platelet transfusions. The authors describe pre-operative intravascular proximal splenic artery control in four adult patients (3 men, 1 woman) with extreme splenomegaly (2,250-10,000 g). The massive splenomegaly in this group resulted from chronic myelogenous leukemia (n = 2), isolated splenic lymphoma (n = 1), and agnogenic myeloid metaplasia (n = 1). Chief symptom manifestations included left upper quadrant abdominal pain, early satiety, post-prandial emesis, dyspnea, petechiae, and associated easy bruising. Prior to surgery, all the patients were taken to the radiology suite where either detachable silastic balloons or stainless steel coils were placed selectively into the splenic artery under fluoroscopic guidance requiring approximately 35 minutes. Splenic artery occlusion aided normalization of thrombocytopenia (average increases 19,000/microliter to 215,000/microliter) with prolongation in survival of platelets. Successful splenectomy was subsequently performed with no additional transfusion requirements and was made technically easier by reducing splenic bulk. There were no adverse consequences of intravascular occlusion and no peri-operative morbidity or mortality. Preoperative intravascular selective splenic artery occlusion, used as an important potential adjunct to anticipated high risk splenectomy, is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1987

Large vessel sealing with the argon laser.

This study compared the histology, biochemistry, and tensile strength of laser-welded and sutured canine venotomies, arteriotomies, and arteriovenous fistulas. Twelve animals had bilateral femoral vessels studied, with one repair (control) closed with interrupted 6-0 polypropylene sutures, and the contralateral repair (experimental) welded with the argon laser. Specimens were examined at weekly intervals from 1 to 4 weeks (four animals for each type of repair), and were evaluated histologically by hematoxylin and eosin, elastin, and trichrome stains; biochemically by the formation of [3H]hydroxyproline as an index of collagen synthesis; and mechanically by tensile strength determinations. At removal, all experimental closures were patent without hematomas, aneurysms, or luminal dilatation. Histologic and biochemical examination and tensile strength determinations suggest that laser welding may be an alternative to sutures for repair of large-diameter venotomies, arteriotomies, and arteriovenous fistulas, as healing is comparable to that seen with suture repairs up to 4 weeks postoperatively.

Animals↗

PubMed1987

Preliminary report: a new technique of enterotomy closure using Nd:YAG laser welding compared to suture repair.

This study compared the histology and tensile strength of Nd:YAG laser welded and sutured small bowel enterotomies in Sprague-Dawley rats. Enterotomies (0.5 cm long) were either welded with the Nd:YAG laser (1 W and 10.6 sec pulses) or repaired with interrupted, simple 6-O silk sutures. Group I consisted of seven animals; five with enterotomies repaired by laser welding and two repaired by suturing. Group II consisted of eight animals with each having both laser and suture repairs. Animals were killed and specimens were removed and examined at 1 day, and at 1, 2, and 3 weeks postoperatively to compare the progression of healing. On macroscopic examination the laser welded enterotomies were closed 84% of the time and only 23% had adhesion formation while 90% of sutured repairs were closed and 100% had adhesion formation. Histologic examination of both suture and laser welded enterotomies demonstrated active healing at 1 week with minimal collagen bridging the enterotomies. At 2 and 3 weeks the sutured enterotomies had granulomatous reaction around the sutures while the laser welded enterotomies had minimal inflammatory response and near normal small bowel histology. The tensile strength of the 3-week specimens from both the suture and laser welded enterotomies were 50% of normal bowel. These findings suggest that the laser welding of small bowel enterotomies is comparable in closure and tensile strength to suture repair. The time required to repair the enterotomy is significantly decreased, the procedure is easily performed, and there is a marked decrease in adhesion formation following laser repair.

Animals↗

PubMed1987

Valvulotomy in in situ vein bypasses performed by angioscope-assisted laser probe.

The objective of this study was to evaluate the use of an angioscope-assisted laser hot-tip probe for performing valvulotomies in in situ nonreversed canine veins used for arterial bypasses. In Group 1, 9 valvulotomies were performed in 7 bypass veins with a 2-mm probe activated by 12 W power, resulting in 4 vein perforations, 1 vein thrombosis, and 4 in situ grafts patent at removal after 2-28 days. In Group 2, 10 valvulotomies in 9 bypass veins were performed with a 1.5-mm probe at 14 W with no vein perforations, 3 vein thromboses, and 6 in situ grafts patent at removal after an interval of 1 to 6 weeks. We conclude that valvulotomy within in situ vein bypasses can be successfully performed using a 1.5-mm laser hot-tip probe at 14 W power, with patency of the grafts demonstrated at 6 weeks. Angioscope-assisted laser valvulotomy using a laser probe may significantly reduce the length of incisions and the time required for in situ vein bypasses and improve the technical accuracy of the procedure.

Animals↗

PubMed1987

Aortitis presenting as Buerger's disease.

Buerger's disease is frequently diagnosed in young smokers, based on clinical presentation rather than histologic criteria. This report describes a young male with idiopathic aortitis who had been managed for 10 years as Buerger's disease solely on the basis of clinical manifestations. This case emphasizes the need for establishing histopathologic, and perhaps biochemical, criteria to identify the underlying arteriopathy.

Adult↗

PubMed1987

Intraoperative video angioscopy compared with arteriography during peripheral vascular operations.

In a prospective study, we assessed the diagnostic and therapeutic applications of intraoperative angioscopy for peripheral vascular procedures. Sixty-seven vessels and 17 bypass grafts were examined with a flexible, multichannel, fiberoptic endoscope (outer diameter 2.8 mm), with video projection of a magnified image used during the following operations: femoropopliteal or femorotibial bypass (14), aortofemoral (six), axillopopliteal bypass (one), and femoral embolectomy (three). Preoperative angiograms were compared with the findings at prebypass intraoperative angioscopy. Immediately after bypass, angioscopic appearances of the graft, anastomosis, and distal runoff artery were compared with a completion angiogram. Significant disparity between angioscopy and arteriography occurred in five patients (21%), with resultant change of management in three (12.5%). In comparison to angioscopy, the arteriograms gave a false negative rate of 12.5% (3 of 24) and a false positive rate of 8% (2 of 24). Angioscopy was accurate for assessment of anastomoses in all cases and was particularly beneficial for monitoring balloon catheter embolectomy. Complications were limited to three instances of vasospasm when the scope was used in narrow vessels. No embolization, intimal trauma, infection, or vessel perforation occurred. We conclude that angioscopy promises to be a safe and accurate alternative technique for intraoperative assessment, monitoring anastomotic results and controlling therapeutic procedures.

Angiography↗

PubMed1987

Argon laser-welded arteriovenous anastomoses.

This study compared the healing of laser-welded and sutured canine femoral arteriovenous anastomoses. Arteriovenous fistulas 2 cm in length were created bilaterally in the femoral vessels of 10 dogs and were studied at 1 (n = 2), 2 (n = 2), 4 (n = 3), and 8 (n = 3) weeks. In each animal, one anastomosis (control) was closed with running 6-0 polypropylene sutures, and the contralateral anastomosis (experimental) was sealed with an argon laser (0.5 watt, 4 minutes of exposure, 1830 J/cm2/1 cm length of anastomosis). At removal all experimental anastomoses were patent without hematomas, aneurysms, or luminal narrowing. Histologic examination at 4 weeks revealed that laser-welded anastomoses had less inflammatory response and almost normal collagen and elastin reorientation. At 8 weeks sutured anastomoses had significant intimal hyperplasia whereas laser repairs had normal luminal architecture. Tensile strength and collagen production, measured by the synthesis of hydroxyproline and the steady-state levels of type I and type III procollagen messenger ribonucleic acids, at the anastomoses and in adjacent vein and artery specimens were similar in sutured and laser-welded repairs at 2, 4, and 8 weeks. We conclude that argon laser welding of anastomoses is an acceptable alternative to suture techniques, with the advantage of improved healing without foreign body response and possible diminished intimal hyperplasia at the anastomotic line.

Animals↗

PubMed1986

Laser welding of venotomies.

We investigated the histologic and biochemical effects of carbon dioxide and neodymium (Nd)-YAG laser welding on the healing of venotomies. Ten canine femoral venotomies 2 cm in length were approximated and welded with 10 600-nm wavelength, 1-W power over 20 to 25 s for CO2 laser, and 1060-nm wavelength, 1-W power over 30 to 40 s for Nd-YAG laser. On removal at one to three weeks, all veins (4/4 welded by CO2 and 6/6 by Nd-YAG) were patent without hematomas. Histologic and biochemical analyses of the venous tissues demonstrated active healing at the venotomy sites. We conclude that the CO2 and Nd-YAG lasers can be used successfully to weld venotomies and may provide an alternative to conventional suture techniques for repair of vascular lesions.

Animals↗

PubMed1986

Comparison of laser-welded and sutured arteriotomies.

We compared the histologic features, tensile strength, and collagen synthesis of laser-welded and sutured arteriotomies. Four bilateral canine femoral or carotid arteries, 2 cm long, were studied at one through four weeks postoperatively, with one vessel (control) closed with interrupted 6-0 polypropylene sutures and the contralateral vessel (experimental) welded with an argon laser (0.5 W [1417 J/cm2], four-minute exposure per 1-cm length of incision). Histologic examination revealed that laser-welded arteriotomies had less inflammatory reaction, more normal collagen and elastin reorientation, and similar endothelial continuity when compared with the control, sutured wounds. The tensile strength of the one- and two-week laser-welded specimens was less than that of sutured wounds and became approximately equal to sutured repairs at three and four weeks. There were no significant differences in the rate of collagen synthesis. There was no evidence of abnormal healing in the laser-welded specimens, suggesting that argon laser welding may be an alternative to suture repair of arteriotomies.

Animals↗

PubMed1986

Biological effects of laser welding on vascular healing.

The feasibility of welding thin-walled microvessels by laser has been established. This report summarizes our experience using laser welding to repair thick-walled, high-pressure, 4 to 8-mm canine arteries using CO2, Nd:YAG, and argon lasers. The CO2 laser did not produce seals that could withstand arterial pressure. Nd:YAG laser welds were initially successful, but the majority failed within 20 to 40 minutes. The argon laser uniformly sealed 2-cm-length arteriotomies that healed rapidly within 4 to 6 weeks and had less foreign body response compared to sutured controls. Laser welding may represent an alternative for repair of small- and large-diameter vessels with several advantages compared to conventional suture techniques.

Animals↗

PubMed1986

Biliary disease in pregnancy: strategy for surgical management.

Acute biliary tract disease complicated intrauterine pregnancy in 26 patients seen during a 5 year period. Biliary symptoms were distinct and occurred during the first trimester in 7 patients, the second trimester in 5 patients, the third trimester in 12 patients, and in two early postpartum patients. Nine patients had marked hyperamylasemia which resolved with medical management, and no severe cases of pancreatitis occurred. Ultrasonography was used to confirm the presence of gallstones in 18 patients and demonstrated dilated intrahepatic ducts in one of two patients with surgically proved choledocholithiasis. Nineteen patients had cholecystectomy and cholangiography, and 4 had common bile duct explorations. Only two of seven patients who presented in the first trimester had term pregnancy. Diagnosis of cholelithiasis in pregnancy by ultrasonography is accurate and reliable. The risk to the fetus of radionuclide scanning and conventional radiography is not justified. Secondary hyperamylasemia is common but responds to conservative therapy. Operation may be delayed until delivery in most patients, with urgent exploration reserved for uncertainty in diagnosis, choledocholithiasis, or acute cholecystitis that does not resolve with medical measures.

Acute Disease↗

PubMed1986

Laser welding: an alternative method of venous repair.

This study compared the histology, biochemistry, tensile strength, and extensibility of Nd:YAG laser-welded and sutured venotomies. Two-centimeter-length bilateral canine femoral or jugular venotomies were evaluated with one vessel (control) closed with interrupted 6-0 polypropylene sutures, and the contralateral vessel (experimental) welded with the Nd:YAG laser (1 W power and 30- to 40-sec exposure). Specimens were removed and examined immediately after fashioning (t0) and at 1, 4, or 5 weeks post-operatively to compare the progression of healing. Histologic examination of the 4- and 5-week sutured wounds had granulomatous reaction around the sutures with areas of excessive collagen accumulation. In contrast, the laser-welded wounds had minimal inflammatory response, near normal collagen content, and minimal residual disorientation and break in the elastic fiber continuity. The rate of collagen synthesis in laser-welded wounds was approximately twice that of sutured wounds at 1, 4, and 5 weeks, and correlated with increased tensile strengths of lasered wounds. The extensibility of the 5-week specimens was 0.19 for sutured and 0.29 for laser-welded wounds as compared to 0.29 for normal vein. These preliminary data suggest that laser welding of venotomies may have several advantages over conventional suture techniques.

Animals↗

PubMed1986

Selective surgical management of perforated duodenal ulcer.

In an effort to clarify the preoperative indications and factors predisposing to an increased operative morbidity for "definitive" ulcer procedures, the medical records of 114 patients with perforated duodenal ulcers were reviewed. One hundred nine patients underwent operation, with 55 patients treated with ulcer closure (Group 1) and 54 underwent a "definitive" operation (Group 2). Thirty-two complications developed in 27 patients (25%), with major infectious complications occurring in 9 per cent and 7.5 percent in the simple ulcer closure and definitive surgery groups, respectively. This study demonstrates that preoperative shock, operation delayed greater than 48 hours, and patient age greater than 60 years were significant factors increasing morbidity. The importance of peritoneal soilage and positive cultures are unreliable in predicting subsequent clinical infection and do not contraindicate definitive surgical management.

Adolescent↗

PubMed1985

Common bile duct anastomosis using fibrin glue.

Transection of the common bile duct (CBD) secondary to iatrogenic or civilian trauma is a devastating injury associated with a high incidence of complications, especially biliary fistula and stricture formation. We evaluated the efficacy of Fibrin Sealant--a biologic adhesive containing highly concentrated human fibrinogen--in primary end-to-end anastomosis of the transected CBD in ten adult mongrel dogs. Postoperative T-tube stents in the CBD anastomosis and abdominal drainage were not used. Only two absorbable sutures were used for each CBD anastomosis. The dogs were reexplored postoperatively at intervals varying from one week to nine months; cholangiography was performed at postoperative intervals varying from one to six months. Examination of CBD specimens harvested one month or more after surgery revealed complete healing and no signs of previous injury. Histologic examination disclosed well-healed ductal tissue, without a significant inflammatory response. One dog had an anastomotic leak, and two had moderate narrowing of the CBD anastomosis. Our experience in experimental CBD anastomosis indicates that Fibrin Sealant helps seal biliary anastomoses against leakage; controls bleeding from cut edges of bile duct segments; has good systemic and local compatibility; may promote bile duct wound healing; and significantly reduces the number of sutures needed for primary repair, thereby decreasing the potential for anastomotic ischemia, mucosal damage, and biliary stricture formation.

Animals↗

PubMed1985

Idiopathic (Bell's) facial palsy: natural history defies steroid or surgical treatment.

Idiopathic (Bell's) facial palsy is a self-limiting, non-life threatening, and spontaneously remitting disorder. The natural history of Bell's palsy is favorable: 84% of 1011 patients with Bell's palsy studied by one investigator recovered satisfactorily without treatment, and no valid clinical trials conducted to date have provided definitive evidence that treatment with steroids or surgery improves upon this figure. The authors studied 273 patients with Bell's palsy to evaluate the prognostic significance of evoked electromyography in predicting the possible benefit of transmastoid facial nerve surgical decompression. The results indicated that even when evoked electromyography was used to select those patients who might benefit most from transmastoid surgery, outcome in patients treated surgically was no better than can be expected to occur without treatment. Based upon these observations, transmastoid facial nerve surgery is not recommended to treat Bell's palsy because no benefits have been identified which outweigh the risks of surgery.

Electric Stimulation↗

PubMed1984

Superiority of transcutaneous oximetry in noninvasive vascular diagnosis in patients with diabetes.

Transcutaneous oxygen tension Ptco2 is directly related to skin oxygen delivery. Regional transcutaneous oximetry ( RTO ) compares peripheral and truncal (Ptco2), yielding a regional perfusion index indicative of local limb perfusion. The relative diagnostic values of RTO , Doppler ankle-brachial pressure ratio (ABR), pulse volume recording (PVR), and toe pulse reappearance time (PRT/2) were studied in 64 limbs of patients with diabetes. These limbs were clinically classifiable into claudication, rest pain, and gangrene groups. Regional transcutaneous oximetry had a higher diagnostic accuracy than ABR (X2 = 27.47, P less than .001), PVR (X2 = 7.54, P less than .01), and PRT/2 (X2 = 10.99, P less than .001). Regional transcutaneous oximetry was universally applicable and the degree of hypoxia observed correlated with clinical symptoms. Significant hypoxia predicted large-vessel angiographic lesions, many of which were reconstructible . Regional transcutaneous oximetry should be the initial noninvasive test in diabetic peripheral vascular disease.

Aged↗