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Biomedical subjects

Ralph V Clayman

Publications and source records attributed to Ralph V Clayman.

At least 109 records · Page 6Linked to original sources
PubMed2002

Use of titanium staples during upper tract laparoscopic reconstructive surgery: initial experience.

PURPOSE: Using nonabsorbable titanium staples in the lower urinary tract during laparoscopic nephroureterectomy has been shown to be safe. Laboratory studies of titanium staples in the upper urinary tract have likewise been favorable. Therefore, we used titanium Endo-GIA tissue staples (United States Surgical, Norwalk, Connecticut) to facilitate laparoscopic reduction pelvioplasty during laparoscopic pyeloplasty. MATERIALS AND METHODS: Of the 17 cases of reduction pelvioplasty closure was done in 12 using absorbable sutures, while in 5 reduction was done with an Endo-GIA stapler. Followup consisted of office visits and telephone interviews plus radionuclide renal scans. RESULTS: Average operative time was 5.5 hours in the Endo-GIA group compared with 6.8 hours in the sutured group. In the latter group extravasation in 2 patients postoperatively was managed conservatively. There was no extravasation in the stapled group. At a median subjective followup of 27 months none of the 5 patients who underwent reduction with titanium staples had symptomatic nephrolithiasis, although new onset urolithiasis developed in 1 in the sutured group. All patients had a greater than 50% decrease in pain. Renal scans at a median of 9 months showed that all ureteropelvic junction repairs were unobstructed. Additional radiographic studies in 2 patients in the stapled group showed a patent ureteropelvic junction and no stones. CONCLUSIONS: Titanium staples provide rapid, secure closure of the renal pelvis during laparoscopic pyeloplasty. While the risk of stone formation is an ongoing concern, it has yet to materialize.

Adult↗
PubMed2002

Incidence of postoperative adhesion formation after transperitoneal genitourinary laparoscopic surgery.

OBJECTIVES: To evaluate adhesion formation after urologic laparoscopy, a multi-institutional review was conducted among adult patients who underwent a second procedure after an initial transperitoneal laparoscopic procedure. Adhesion formation after abdominal surgery remains a major cause of postoperative morbidity. Peritoneal adhesions result in hospitalizations and interventions that result in healthcare costs of more than 1 billion dollars annually. The risk of adhesion formation from transperitoneal genitourinary laparoscopy in adults has not been previously studied. METHODS: Twenty-seven patients (mean age 45.5 years, range 24 to 71) were identified who underwent a second laparoscopic procedure after their initial urologic laparoscopic procedure was performed. The mean time between the procedures was 11.4 months (range 8 days to 38 months). At the time of the repeated laparoscopy or open surgery, the peritoneal cavity was examined and mapped for type (grade), extent (length), and location of any adhesions at the operative and trocar sites. The adhesions were graded as 0, no adhesions; 1, flimsy; 2, dense; and 3, cohesive. The extent was graded as 0, no adhesions; 1, less than 2 cm; 2, 2.1 to 10 cm; 3, greater than 10.1 cm. RESULTS: Overall, adhesions occurred in 6 (22.2%) of 27 patients. Operative site adhesions occurred in only 3 (8.2%) of 34 possible operative sites (gastric augmentation cystoplasty, renal cyst ablation, nephropexy). Trocar site adhesions occurred in 4 (3.5%) of 114 possible sites (two nephrectomies, one cyst decortication, and one orchiectomy). All adhesions were classified as grade 1 and extent 1, except for a single grade 2, extent 2 adhesion. In most patients, retroperitonealization occurred with minimal or no scarring noted. None of the patients developed symptoms as a result of the adhesion formation. CONCLUSIONS: Although intraperitoneal adhesions do occur with adult urologic laparoscopy, the incidence is low. Also, in the few patients who do form adhesions, they are flimsy and short. This evidence, when contrasted with the available data on adhesion formation after open surgery, suggests that transperitoneal laparoscopic approaches to genitourinary surgery may have advantages over traditional open transperitoneal approaches by lowering the incidence and severity of adhesion formation.

Adult↗
PubMed2002

Bare naked baskets: optimizing ureteroscopic stone extraction.

Baskets placed through the working channels of flexible ureteroscopes limit mobility and irrigant flow. We describe a new technique to minimize these limitations. An unsheathed "bare naked" basket affords enhanced ureteroscopic efficacy by limiting obstruction of the working channel. We have used the technique clinically to treat stones in difficult locations successfully and to remove fragments of calculi after ureteroscopic lithotripsy.

Equipment Design↗
PubMed2002

Maximizing ureteroscope deflection: "play it straight".

We studied simple maneuvers to optimize active deflection of the flexible ureteroscope. Up to 61 degrees of active deflection is lost if the ureteroscope is not kept in a straight alignment. Holding the ureteroscope taut, placing a super-stiff guidewire in the working channel, or using an access sheath maximizes active deflection.

Humans↗
PubMed2002

Effect of single-dose subarachnoid spinal anesthesia on pain and recovery after unilateral percutaneous nephrolithotomy.

PURPOSE: We studied the impact of one dose of subarachnoid spinal analgesia on postoperative pain and recovery after percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: Between August 1999 and May 2000, 20 PCNL patients were randomized into two groups: Group A (N = 9), who received preoperative subarachnoid spinal analgesia with morphine sulfate, and Group B (N = 11), who received no subarachnoid spinal analgesia. Both groups were given general anesthesia, and the nephrostomy site was infiltrated with bupivacaine hydrochloride. Stone size was similar in the two groups, as were ASA classification, age, and body mass index. Pain analog scales (maximum score 10) were completed preoperatively and on the day of surgery (D0), after 1 day (D1), and after 2 days (D2). The amount of morphine sulfate equivalents (MS eq) needed, the activity level, and adverse effects were recorded. RESULTS: In Group A, the average pain score on D0, D1, and D2 was 2.7, 3.7, and 1.4, respectively; in Group B, the average pain score was 4, 4.5, and 2, respectively (P > 0.05). The average MS eq used in Groups A and B were 8.3 v 33.8 (P = 0.002) on D0; 17.7 v 28.7 (P > 0.05) on D1; and 11.1 v 10.1 (P > 0.05) on D2. On D0, in Group A, 56% of the patients were ambulating and 11% complained of nausea, while in Group B, 0 were ambulating and 46% complained of nausea. CONCLUSIONS: A single preoperative dose of subarachnoid spinal analgesia provides a statistically significant decrease in postoperative parenteral pain medication and earlier ambulation. It also appears to reduce the amount of postoperative pain and decrease nausea.

Adult↗
PubMed2002

Effect of argon-beam coagulation on the integrity of suture material.

PURPOSE: To evaluate the effect of argon-beam coagulator (ABC) energy on suture materials. MATERIALS AND METHODS: Six absorbable and nonabsorbable suture materials (polyglactin, chromic catgut, polydioxanone, silk, poliglecaprone, and Gore-Tex) were placed under tension and exposed to ABC energy to determine breaking times. Subsequently, all suture materials were exposed to limited ABC energy, and tensiometry was used to determine decreases in breaking strengths. RESULTS: Among the suture materials tested, Gore-Tex was the most resistant to ABC energy. Although absorbable suture materials were less resistant than nonabsorbable suture materials, 2-0 polyglactin manifested the greatest resiliance to deterioration with ABC energy exposure. CONCLUSIONS: The ABC has differential effects on suture materials. Larger-gauge suture materials are more resistant to ABC than smaller materials. Similarly, nonabsorbable sutures are generally more resilient to ABC energy than absorbable materials. Among the suture materials evaluated in our in vitro model, 2-0 Gore-Tex was best suited for vascular ligation, and 2-0 polyglactin is optimal for renal collecting system closure if ABC is anticipated as an adjunct for hemostasis.

Absorbable Implants↗
PubMed2002

Current management of urolithiasis: progress or regress?

PURPOSE: To assess the impact of the development of less powerful second- and third-generation shockwave lithotripters on surgical stone therapy in light of recent advances in ureteroscopy and laser lithotripsy. As such, we sought to identify current trends in the treatment of stone disease, both at our university medical center and nationally, and to contrast them with the corresponding data from 1990. PATIENTS AND METHODS: All urolithiasis procedures (ureteroscopy, SWL, open surgery, and percutaneous stone removal) performed in 1998 were compared with all urolithiasis procedures performed 8 years earlier (1990) at a single institution (Washington University, St. Louis). In addition, Medicare data for each year from 1988 through 2000 were collected from the Health Care Financing Administration to assess the national trends for open stone surgery, ureteroscopic stone removal, SWL, and percutaneous nephrolithotomy. RESULTS: At Washington University, the number of percutaneous stone removals remained stable; however, the overall number of ureteroscopies increased by 53%, while the number of SWLs, decreased by 15%. The Medicare data likewise reflect a marked decrease in open stone surgery and a marked increase in ureteroscopic stone surgery with a slight increase in SWL. Utilization of percutaneous nephrolithotomy remained unchanged. CONCLUSIONS: We believe this trend toward ureteroscopy is attributable to several factors: improved, smaller rigid and flexible ureteroscopes; the availability of more effective intracorporeal lithotripters (e.g., pneumatic and holmium laser), and the lack of development of lower cost, more effective SWL. This is an unfortunate trend, as we are moving away from the noninvasive treatment that was the hallmark of urolithiasis therapy at the beginning of the last decade toward more invasive endoscopic therapy. Increased research efforts in SWL technology are sorely needed.

Female↗
PubMed2002

Renal hypothermia achieved by retrograde intracavitary saline perfusion.

BACKGROUND AND PURPOSE: Hypothermia during vascular clamping protects the kidney from ischemia-induced nephron loss. Traditionally, cooling is achieved by packing the kidney in ice, which lowers the temperature of the rest of the surgical field as well, and the method cannot be used during laparoscopy. We evaluated the utility of a newly developed ureteral access system for circulating ice-cold saline. MATERIALS AND METHODS: Domestic pigs underwent retrograde endoscopic cooling through an access sheath without (N = 2) or with (N = 3) renal artery occlusion, traditional ice-slush cooling with renal artery occlusion (N = 3), or occlusion without hypothermia (N = 3). Five days later, the pigs were sacrificed and the kidneys and ureters examined histologically. RESULTS: Endoscopic cooling with renal artery occlusion and ice-slush cooling both produced renal hypothermia. The former produced medullary and cortical temperatures of 21.3 degrees C and 27.3 degrees C, respectively, and the latter medullary and cortical temperatures of 28.8 degrees C and 23.7 degrees C, respectively. Histologically, there were minimal changes in the first three groups, whereas venous congestion, multifocal chronic inflammation, and periarteriolar hemorrhage were seen after renal artery occlusion without hypothermia. CONCLUSION: Retrograde endoscopic renal hypothermia is effective and requires no novel equipment or special surgical skills. Clinical application has not yet been attempted.

Animals↗
PubMed2002

Ferromagnetic self-regulating reheatable thermal rod implants for in situ tissue ablation.

BACKGROUND AND PURPOSE: Ferromagnetic compounds, when placed in a radiofrequency magnetic field, develop an electrical current. When placed in tissue, resistance to the transmission of the electrical current leads to heating of the tissues next to the ferromagnetic compound. The Curie temperature is a transition point at which the development of a particular temperature within the material results in loss of its magnetic properties; as such, when this temperature is reached, there is cessation of current, and thus heat production stops. Our goal was to examine the ablative impact of permanently implanted palladium and cobalt self-regulating temperature rods on solid abdominal and pelvic organs. These rods were designed to develop a maximum temperature of 70 degrees C. MATERIALS AND METHODS: In 16 pigs, renal, hepatic, uterine, and pancreatic ferromagnetic rods were placed using a template. The rods were delivered in 1-cm parallel rows of two rods each in order to ablate 7 g of tissue. The animals were subsequently treated in an extracorporeal magnetic field of 50 gauss rms at a frequency of 50 kHz. The position of the rods was confirmed by fluoroscopy before the animal was put in the magnetic field. The animals received one or two treatment sessions. Intralesional and extralesional temperatures were measured continuously. Serum chemistry was analyzed before surgery, after each treatment, and at the time of harvest. Two weeks following therapy, the treated tissues were harvested and examined histopathologically. RESULTS: In all tissues with properly aligned rods, the temperature of the tissue surrounding the rods exceeded 50 degrees C. Histologic review showed confluent tissue necrosis in 7 of 9 kidneys (78%), 6 of 9 livers (67%), 1 of 3 pancreases (33%), and 1 of 3 uterine specimens (33%). Necrosis extended for 2 mm beyond the periphery of the rods. All failures were secondary to technical misalignment of the rods, which occurred because of our attempt to treat more than one organ in each animal. CONCLUSIONS: Ferromagnetic rods, when properly aligned in a magnetic field, create well-defined areas of necrosis. There are no skip areas of viable tissue within the treated area, and there is a precipitous fall-off of injury just outside the area of treatment. Also, because the rods can be reactivated at any time, recurrent lesions within the same site can be treated. This form of minimally invasive in situ ablative therapy appears promising. Clinical trials in the kidney and in other abdominal and pelvic organs are pending.

Animals↗
PubMed2002

Laparoscopic partial nephrectomy with a novel electrosurgical snare in a porcine model.

PURPOSE: We evaluated the safety and efficacy of laparoscopic partial nephrectomy with an arcing-gap electrosurgical snare in a porcine model. MATERIALS AND METHODS: A novel electrosurgical snare, optimizing high current density arcing and parenchymal compression, was utilized for laparoscopic renal transection. Five farm pigs underwent unilateral laparoscopic polar partial nephrectomy; 6 weeks later, these same animals underwent contralateral partial nephrectomy just prior to sacrifice. Five additional animals underwent chronic (6-week follow-up) and acute open partial nephrectomies by the conventional surgical technique. RESULTS: The average time for transection with the snare was 5.6 minutes. In 9 of 10 cases, the snare provided satisfactory hemostasis. In the remaining case, additional argon-beam coagulation (ABC) controlled the minimal bleeding present after transection. In all 10 animals, the collecting system was transected. In six cases, application of the snare alone sealed the collecting system. No urinomas developed in the five animals followed for 6 weeks. At 6 weeks, the mean depth of injury at the center of the cut surface was 5.1 mm in the laparoscopic group and 3.9 mm in the open group. CONCLUSIONS: Laparoscopic partial nephrectomy with the arcing-gap electrosurgical snare is feasible in a porcine model. Application of the snare provides excellent hemostasis without the need to control the renal vasculature.

Animals↗