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Biomedical subjects

Ralph V Clayman

Publications and source records attributed to Ralph V Clayman.

At least 91 records · Page 5Linked to original sources
PubMed2003

Surgical treatment of renal neoplasia: evolving toward a laparoscopic standard of care.

OBJECTIVES: To determine the extent to which laparoscopy has replaced open surgery for renal malignancy. METHODS: The records of all 537 patients at Washington University who underwent surgery for localized renal malignancies from January 1997 to December 2001 were examined for clinical and pathologic information. RESULTS: The total procedures per year increased from 1997 to 2001, but the distribution of pathologic stages throughout the 5 years was similar. In 1997, laparoscopic approaches were used in 15% of cases; this increased to 65% by 2001. Nephron-sparing surgery (NSS) was used in 31% to 42% of patients yearly, but laparoscopic NSS increased in frequency. By 2001, only 3.3% of T1 tumors were removed by open radical nephrectomy compared with 55% treated by laparoscopic nephrectomy. The rest of the T1 tumors in 2001 were treated by open partial nephrectomy (20.2%) or laparoscopic NSS (21.3%). In 2001, 61% of T2 lesions were treated laparoscopically, an increase from 37% in 1997. Most open radical nephrectomies in 2001 were performed for T3 disease. The number of surgeons performing laparoscopic renal surgery has increased at our institution, from two in 1997, both endourologists, to eight in 2001, representing the entire urology faculty that treats renal cancer. CONCLUSIONS: Laparoscopic radical nephrectomy has replaced open radical nephrectomy for low-stage renal neoplasia. Although laparoscopic NSS is increasing in frequency, it has not yet replaced open partial nephrectomy. At our institution, the laparoscopic approach has become the standard of care when radical nephrectomy is needed for T1 or T2 renal cancer.

Carcinoma, Renal Cell↗
PubMed2003

Evaluation of synchronous twin pulse technique for shock wave lithotripsy: in vivo tissue effects.

OBJECTIVES: To study the in vivo tissue effects of synchronous twin pulse technology. Recently, the concept of a synchronous twin pulse technique for shock wave therapy has been introduced with the development of the Twinheads' unit. METHODS: In 10 pigs (20 kidneys), one of three sites was targeted: the renal pelvis (2 pigs), the mid-zone parenchyma (5 pigs), or the lower pole parenchyma (3 pigs). The treatment parameters were 1000 twin shock waves at 14 kV with a 90 degrees angle between the shock wave reflectors using a rate of 60 shock waves/min in 17 kidneys and 120 shock waves/min in 3 kidneys. To study the effect of an increasing number of twin shock waves, 4 animals (8 kidneys) were used; the mid-zone parenchyma was subjected to 2000 and 3000 twin shock waves in 4 kidneys each, using a rate of 60 shock waves/min at 14 kV and a 90 degrees angle in all of them. For comparison with the use of a single head, another 3 animals (6 kidneys) were treated with the use of the single under-table head; all of them received 2000 single shock waves at 14 kV focused on the mid zone of the kidney parenchyma. Within 1 hour of treatment, the treated kidneys were harvested, inspected, and sectioned at the focal site, as well as at 1 and 2 cm distant to the focal site. RESULTS: No gross lesions of the surrounding organs, subcapsular hemorrhage, or parenchymal damage were found at the outer surfaces of the kidneys undergoing twin head shock wave lithotripsy even after 3000 twin shocks. The coronal section revealed minimal gross lesions in 4 of 28 kidneys. Microscopically, the parenchymal changes were minimal. In vivo study of the use of the single under-table head revealed that 5 of 6 kidneys had large subcapsular hematomas at both anterior and posterior surfaces and on coronal section extending into the parenchyma. Microscopically, the changes were significant. CONCLUSIONS: Synchronous twin pulse shock waves induced minimal damage compared with single pulse standard shock waves. Of note, even after 3000 twin pulses (ie, a total of 6000 shock waves), the renal damage remained minimal.

Animals↗
PubMed2003

Tissue chemoablation.

PURPOSE: To provide an overview of the state of the art of tissue chemoablation in animal and human organs and cancers. We also describe our experience with the feasibility, predictability, and reproducibility of necrosis produced by needle chemoablative therapies including ethanol, hypertonic saline, and acetic acid solutions as well as gels in a porcine renal model. MATERIALS AND METHODS: A MEDLINE search was performed for articles on animal and human tissue chemoablation published since 1965. In addition, at Washington University, experimental chemoablation was performed in pigs with 95% ethanol (4 mL), 24% hypertonic saline (4 mL), or 50% acetic acid (4 mL) solutions as well as in gel form. RESULTS: There is extensive literature on the use of chemoablation for liver metastases; recently, chemoablation of the prostate has become an area of research. Human studies have been limited to patients who are not surgical candidates or to investigational procedures performed prior to definitive prostatic surgery. Animal studies of renal chemoablation as a sole therapy have produced mixed results. In our studies, only acetic acid provided complete necrosis. CONCLUSIONS: To date, ethanol chemoablation has been shown to be feasible and reproducible only for metastatic hepatic carcinoma. In urology, chemoablation is still very much in the investigational stage for both the prostate and the kidney. A significant drawback is that even in the gel form, the spread of the chemoablative substance through the tissue is irregular and unpredictable. In the future, chemoablation may become a more effective modality by combining it with radiofrequency or other energy sources.

Acetic Acid↗
PubMed2003

Effect of lithotripsy on holmium:YAG optical beam profile.

PURPOSE: To determine the effect of holmium:YAG lithotripsy on the optical beam profile. MATERIALS AND METHODS: Beam profiles of the laser light from holmium:YAG optical fiber systems were characterized with a pyroelectric camera. Beam profiles were measured with 272-microm and 365-microm optical fibers both straight and bent to simulate lower-pole ureteronephroscopy. Struvite calculi were irradiated. Beam profiles and energy outputs were characterized for the fibers before and after ablation. Ablation crater geometry was characterized with optical coherence tomography. RESULTS: Undamaged, straight fibers produced a near-Gaussian beam profile. Craters showed a similar near-Gaussian shape. Undamaged, bent 272-microm fibers produced a near-Gaussian beam but slightly flatter profile than the straight fiber. The bent 272-microm fiber transmitted 99% to 100% of the energy, similar to the 100% transmission of the straight fibers. After ablation, measured energy output dropped by 30% within 50 pulses at 0.2 J pulse energy. The damaged fibers produced irregular beam profiles with hot spots. Craters showed irregular contours. CONCLUSIONS: During Ho:YAG lithotripsy, the beam profile at the optical fiber tip approaches a Gaussian distribution. This shape corresponds to the crater produced on the stone surface. With further ablation, the beam profile becomes erratic and unpredictable, with loss of lithotripsy efficiency. The findings provide further insight into the photothermal mechanism of Ho:YAG lithotripsy.

Humans↗
PubMed2003

Laparoscopic cyst decortication in autosomal dominant polycystic kidney disease: impact on pain, hypertension, and renal function.

BACKGROUND AND PURPOSE: In patients with autosomal dominant polycystic kidney disease (ADPKD), laparoscopic cyst decortication (LCD) has been proposed as a means to relieve chronic cyst-related pain. We present our 7-year experience with LCD for ADPKD with regard to pain relief, hypertension, and renal function. PATIENTS AND METHODS: Between August 1994 and February 2001, 29 ADPKD patients with chronic pain (N=29), hypertension (N=21), and renal insufficiency (N=10) underwent 35 LCD procedures. Every detectable cyst within 2 mm of the renal surface was treated. Pain relief was assessed using a pain analog scale; relative pain relief (RPR) equaled (preoperative pain score) - (postoperative pain score)/(preoperative pain score). Hypertension was evaluated using the antihypertensive therapeutic index (ATI): [(dose of blood pressure medication 1/max dose 1) + (dose med 2/max dose 2) + etc.] x 10. Renal function was assessed using the Cockcroft and Gault formula for creatinine clearance. RESULTS: The mean operating room time was 4.9 hours (range 2.6-6.6 hours) with no conversions to open surgery. An average of 220 cysts (range 4-692) were treated per patient. The mean follow-up was 32.3 months (range 6-72 months). The RPR was 58%, 47%, and 63% at 12, 24, and 36 months, respectively. At 12, 24, and 36 months, 73%, 52%, and 81% of patients, respectively, noted >50% improvement in their pain compared with the preoperative situation. Five patients became normotensive, and patients improved their ATI by an average of 49% (range 11%-93%). However, six patients had worsening hypertension, with an ATI increase averaging 53% (range 11%-122%), and one patient who was not hypertensive preoperatively has since developed hypertension. The creatinine clearance changed +4%, +7%, and -2% at 12, 24, and 36 months, respectively. Only one patient had a >20% increase in creatinine clearance. The only patients with a >20% decrease in creatinine clearance were those who had a creatinine clearance <30 mg/dL preoperatively (average decrease 34% [range 20%-51%]). CONCLUSIONS: For ADPKD patients with debilitating pain, extensive LCD can provide durable relief. In the majority of patients with pain and hypertension, a marked improvement in blood pressure also occurs. Cyst decortication was not associated with worsening renal function; indeed, renal function remained largely unchanged over the 3-year follow-up period.

Adult↗
PubMed2003

Evaluation of a vessel sealing system, bipolar electrosurgery, harmonic scalpel, titanium clips, endoscopic gastrointestinal anastomosis vascular staples and sutures for arterial and venous ligation in a porcine model.

PURPOSE: We assessed the usefulness of the LigaSure (Valleylab, Boulder, Colorado) vessel sealing system for vascular control during laparoscopic surgery and compared it with other available hemostatic modalities. MATERIALS AND METHODS: A total of 31 domestic pigs were divided into 5 groups. In groups 1 and 2 the vessel sealing system was compared with titanium clips and Endo-GIA (United States Surgical, Stamford, Connecticut) staples. In group 3 the vessel sealing system was compared with standard Klepinger (Karl Storz, Culver City, California) bipolar forceps. In group 4 the harmonic scalpel and Trimax (United States Surgical) bipolar forceps were compared. In group 5 in vivo laparoscopic application of the vessel sealing system was evaluated. RESULTS: The 5 mm. laparoscopic vessel sealing system sealed arteries up to 6 mm. and veins up to 12 mm. in diameter at supraphysiological bursting pressure. We evaluated 13 arteries with a diameter of 6 mm. or less at a mean bursting pressure of 662 mm. Hg (range 363 to 1,985) and 11 veins with a diameter of 12 mm. or less with a mean bursting pressure of 233 mm. Hg (range 63 to 440). Collateral tissue damage extended 1 to 3 mm. from the application site. Standard bipolar energy with Klepinger and Trimax forceps was less reliable and in some cases vessel sealing could not be accurately assessed before vessel division. Collateral tissue injury was 1 to 6 mm. The harmonic scalpel did not reliably seal vessels larger than 3 mm. but resulted in the least acute collateral tissue injury of 0 to 1 mm. CONCLUSIONS: In the porcine model the LigaSure system is a viable option for laparoscopic management of arteries up to 6 mm. and veins up to 12 mm. in diameter.

Anastomosis, Surgical↗
PubMed2003

Laparoscopic pyeloplasty for secondary ureteropelvic junction obstruction.

PURPOSE: Laparoscopic pyeloplasty has become a viable option for the treatment of select patients with primary ureteropelvic junction obstruction with success rates similar to those of open surgery. However, little has been written on the application of this technique for secondary ureteropelvic junction obstruction. We report the largest series of secondary ureteropelvic junction obstruction managed by laparoscopic pyeloplasty. MATERIALS AND METHODS: Between March 1994 and March 2001, 36 patients underwent laparoscopic transperitoneal pyeloplasty for secondary ureteropelvic junction obstruction. The patients had undergone an average of 1.3 ureteropelvic junction procedures (range 1 to 4) prior to presentation, including cutting balloon retrograde endopyelotomy in 28, antegrade endoscopic endopyelotomy in 7, retrograde endoscopic endopyelotomy in 4, retrograde balloon dilation in 4 and open pyeloplasty in 3. A preoperative diagnosis of recurrent obstruction was confirmed by renal scan in 31 cases, retrograde pyelography in 2 and computerized tomography in 3. Of the 31 patients who underwent spiral computerized tomography angiogram 87% had crossing vessels. Laparoscopic repair comprised dismembered pyeloplasty in 31 cases, Fengerplasty in 3 and flap repair in 2. Postoperative renal scan or excretory urography objective followup was available for all patients at a mean of 10 months (range 3 to 40). Postoperative subjective patient well-being was assessed using an analog pain scale at a mean followup of 21.8 months (range 3 to 85). RESULTS: Average operative time was 6.2 hours (range 2.7 to 10). Average hospital stay was 2.9 days (range 1 to 7). One intraoperative complication occurred, that is bleeding necessitating conversion to an open procedure. Postoperative complications occurred in 8 cases, including anastomotic leakage in 4, and urinary tract infection, pneumonia, atelectasis, fever, bilateral upper extremity weakness and stone formation 2 months postoperatively in 1 each. On excretory urography, furosemide renal scan or the Whitaker test 32 of 36 patients (89%) had a widely patent ureteropelvic junction. Two patients (5.5%) had equivocal radiographic studies but were asymptomatic. In 2 patients the ureteropelvic junction was obstructed by renal scan. One patient had an indwelling stent for renal function deterioration and 1 was asymptomatic. Hence, 34 of the 36 patients (94%) had a reasonable objective response. Overall a 50% or greater decrease in pain was seen in 32 of 36 patients (89%). In the 4 patients with a less than 50% decrease in pain objective renal scans showed an open ureteropelvic junction. As such, the overall success rate of a greater than 50% decrease in pain, a patent ureteropelvic junction and stable or improved function of the affected renal unit was 83% (30 of 36 patients). CONCLUSIONS: For secondary ureteropelvic junction obstruction, laparoscopic pyeloplasty can be performed safely with a success rate comparable to that of standard open pyeloplasty. The patient benefits of laparoscopic ureteropelvic junction repair of secondary ureteropelvic junction obstruction are similar to the benefits of laparoscopic repair of primary ureteropelvic junction obstruction.

Adolescent↗
PubMed2003

Successful transfer of open surgical skills to a laparoscopic environment using a robotic interface: initial experience with laparoscopic radical prostatectomy.

PURPOSE: For a skilled laparoscopic surgeon the learning curve for achieving proficiency with laparoscopic radical prostatectomy (LRP) is estimated at 40 to 60 cases. For the laparoscopically naïve surgeon the curve is estimated at 80 to 100 cases. The development of a robotic interface might significantly shorten the LRP learning curve for an experienced open yet naïve laparoscopic surgeon. To our knowledge we report the initial experience with robot assisted LRP of a surgeon without laparoscopic experience. MATERIALS AND METHODS: Following a 1-day da Vinci (Intuitive Surgical, Mountain View, California) robotic laparoscopic training course and 2 cadaveric robotic LRPs an experienced oncologist (TEA) without laparoscopic experience performed 45 robotic LRPs. RESULTS: All procedures were successfully completed laparoscopically with no rectal injuries or transfusions. The learning curve to 4-hour proficiency was 12 patients and mean operating time subsequently was 3.45 hours (range 2.5 to 5.1). Mean blood loss was 145 cc (range 25 to 350), the mean postoperative day 1 decrease in hemoglobin was 2.6 mg/dl (range 1.9% to 5.1) and mean hospital stay was 36 hours (range 18 to 168). Mean Gleason score was 6.8, mean prostate volume was 50.5 gm (range 12.5 to 163) and the margin positive rate was 35.5%. Four patients (8.8%) had a total of 6 complications, which were managed conservatively. Catheterization time was 7 days (range 7 to 42). Continence (0 pads) was 33% at 1 week, 63% at 1 month and 81% at 3 months. CONCLUSIONS: A laparoscopically naïve yet experienced open surgeon successfully transferred open surgical skills to a laparoscopic environment in 8 to 12 cases using a robotic interface. This outcome is comparable to the reported experience of skilled laparoscopic surgeons after more than 100 LRPs.

Aged↗
PubMed2003

Evaluation of synchronous twin pulse technique for shock wave lithotripsy: determination of optimal parameters for in vitro stone fragmentation.

PURPOSE: The Twinheads extracorporeal shock wave lithotriptor (THSWL) is composed of 2 identical shock wave generators and reflectors. One reflector is under the table and the other is over the table with a variable angle between the axes of the 2 reflectors. The 2 reflectors share a common second focal point, making it possible to deliver an almost synchronous twin pulse to the targeted stone. We studied the optimal parameters for in vitro stone fragmentation. MATERIALS AND METHODS: Two types of 1 cm artificial stones were used, namely Bon(n)-stones of 3 compositions (75% calcium oxalate monohydrate [COM] plus 25% uric acid, struvite and cystine) and plaster of Paris. The parameters tested were shock wave number (100, 500 and 1,000), shock wave power (8, 11 and 14 kV) and angle between the reflector axes (67, 90 and 105 degrees). After the optimal parameters were determined we studied the disintegrative efficacy of THSWL for 3 types of human urinary calculi, including COM, calcium hydrogen phosphate (brushite) and cystine. Each stone received 1,000 twin shock waves at 14 kV with an angle of 90 degrees between the reflectors. All experiments were done using a rate of 60 twin shock waves per minute. Following lithotripsy stone fragments were processed and sized. The ratio of the weight of fragments greater than 2 mm-to-total weight of all fragments was calculated. RESULTS: Optimal stone fragmentation results for THSWL were obtained with the maximum number of shock waves (1,000) and full power (14 kV). There was no significant statistical difference in fragment size or the ratio of fragments greater than 2 mm with the use of different angles except for cystine and plaster of Paris calculi, for which the right angle was most effective. At application of the optimal parameters to human stones THSWL produced small fragment size for COM and cystine stones, while brushite stones were not fragmented to the same extent. CONCLUSIONS: The efficacy of synchronous twin pulse technology improves as the number of shock waves and power increase. A 90-degree angle between the shock wave reflectors is advantageous for certain stones (that is cystine and plaster of Paris) but it is not a factor for other stone compositions. THSWL has satisfactory disintegrative efficacy for human stones, especially COM and cysteine calculi.

Calcium Oxalate↗