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Biomedical subjects

A W Chiu

Publications and source records attributed to A W Chiu.

At least 19 recordsLinked to original sources
PubMed1998

Retroperitoneal and pelvic extraperitoneal laparoscopy: an international perspective.

OBJECTIVES: To assess technical preferences and current practice trends of retroperitoneal and pelvic extraperitoneal laparoscopy. METHODS: A questionnaire survey of 36 selected urologic laparoscopic centers worldwide was performed. RESULTS: Twenty-four centers (67%) responded. Overall, 3988 laparoscopic procedures were reported: transperitoneal approach (n = 2945) and retroperitoneal/extraperitoneal approach (n = 1043). Retroperitoneoscopic/extraperitoneoscopic procedures included adrenalectomy (n = 74), nephrectomy (n = 299), ureteral procedures (n = 166), pelvic lymph node dissection (n = 197), bladder neck suspension (n = 210), varix ligation (n = 91), and lumbar sympathectomy (n = 6). Mean number of total laparoscopic procedures performed in 1995 per center was 41 (range 5 to 86). Major complications occurred in 49 (4.7%) patients and included visceral complications in 26 (2.5%) patients and vascular complications in 23 (2.2%). Open conversion was performed in 69 (6.6%) patients, electively in 41 and emergently in 28 (visceral injuries, n = 16; vascular injuries, n = 1 2). Retroperitoneoscopy/extraperitoneoscopy is gaining in acceptance worldwide: in 1993, the mean estimated ratio of transperitoneal laparoscopic cases versus retroperitoneoscopic/ extraperitoneoscopic cases per center was 74:26; however, in 1996 the ratio was 49:51. CONCLUSIONS: Retroperitoneoscopy and pelvic extraperitoneoscopy are important adjuncts to the laparoscopic armamentarium in urologic surgery. The overall major complication rate associated with retroperitoneoscopy/extraperitoneoscopy was 4.7%.

Humans↗
PubMed1997

Clinical outcome at 3 months after transurethral vaporization of prostate for benign prostatic hyperplasia.

OBJECTIVES: To evaluate the clinical outcome of transurethral vaporization of the prostate (TUVP) for the management of benign prostatic hyperplasia (BPH). METHODS: Between March and June 1995, 30 patients with symptomatic BPH treated by TUVP were enrolled in this study. Transrectal ultrasonography (TRUS) was done preoperatively. American Urological Association (AUA) symptom score determination, pressure flow study, and questionnaire (for evaluating potency) were done preoperatively and 3 months postoperatively. RESULTS: The average age was 70.5 years (range 60 to 83) and estimated prostate size by TRUS before surgery was 33.8 +/- 14.0 g. The average AUA symptom score decreased significantly 3 months after TUVP (6.2 +/- 7.8 versus 18.2 +/- 9.0; P < 0.01). The maximum urine flow rate (Qmax) was 11.1 +/- 3.7 mL/min before TUVP (mean +/- SD) and 17.0 +/- 6.5 mL/min 3 months after TUVP, whereas the detrusor pressure at maximum urine flow (Pdes at Qmax) was 61.0 +/- 23.9 and 41.2 +/- 15.2 cm H2O, respectively. Qmax increased and Pdes at Qmax decreased significantly 3 months after TUVP. Of the 30 patients, 3 (10%) developed bladder neck contracture. Of the 24 patients who were potent sexually before operation, 3 (12.5%) developed impotence 3 months after surgery. CONCLUSIONS: TUVP is an effective alternative surgical procedure to relieve obstruction for patients with symptomatic BPH. However, cautious attitude on its usage is advocated based on our preliminary results indicating the occurrence of late complication such as impotence and bladder neck contracture.

Aged↗
PubMed1997

Is renal function at the tumor side a prognostic factor in ureteral transitional cell carcinoma?

OBJECTIVES: To evaluate whether the ipsilateral renal function on the tumor side is a prognostic factor in transitional cell carcinoma (TCC) of the ureter. PATIENTS AND METHODS: We retrospectively reviewed 129 consecutive patients with ureteral TCC between September 1973 and July 1993 at our hospital. There were 98 males and 31 females aged from 31 to 84 years (mean 64.9). Of them, 126 patients who received intravenous pyelography (IVP) were divided into 3 groups according to their radiological findings (group 1: nonvisualization of kidney at tumor side; group 2: hydronephrosis or hydroureter; group 3: no obstruction). Eighty patients receiving radionuclide (131I-hippuran) renal function test (RRFT) with available effective renal plasma flow (ERPF) were divided into 2 groups using ipsilateral ERPF 50 ml/min as a cutoff value (group 1: < 50 ml/min; group 2: > or = 50 ml/min). The mean survival of each group was estimated by the Kaplan-Meier method. RESULTS: For patients receiving IVP, the mean survivals were 61.7, 99.7 and 83.8 months for groups 1, 2, and 3, respectively, and the differences between each 2 of the 3 groups were statistically significant (p < 0.05). For patients having RRFT, the mean survivals were 65.8 months for group 1 and 89.2 months for group 2 patients, and the difference between them was statistically significant (p < 0.05). When renal function, tumor number, grade, stage and type of treatment were analyzed using a multivariate method, only tumor stage was statistically significant as a prognostic factor. CONCLUSION: Ipsilateral renal function at the tumor side is not a good prognostic factor for patients with ureteral TCC. However, when the stage of tumor is not available, renal function at the tumor side may provide an implication of the patient's prognosis.

Adult↗
PubMed1996

A porcine model for renal hemodynamic study during laparoscopy.

Laser Doppler flowmetry (LDF) is a sensitive method for the measurement of microvascular blood flow in tissue. The method has been found useful for estimating skin, liver, or gastrointestinal blood flow. Whether it can be applied laparoscopically and whether it is able to measure the intraparenchymal blood flow of an intraabdominal organ is still unknown. In a pilot study, 6 pigs received a laparotomy for placement of a 19-gauge LDF needle probe into the renal parenchyma. Three different locations of the lower pole kidney were chosen for the blood flow measurement. The reliability of using the instrument to measure the renal tissue blood flow was assessed by comparison of the results of renal arterial blood flow obtained from a well-established methodology--ultrasonic Doppler flowmetry. Recordings were taken following (a) intravenous administration of 0.005 mg/kg norepinephrine, (b) manual compression of the suprarenal aorta, and (c) intravenous injection of a lethal dose of phenobarbital (50 mg/kg). Measurements of LDF were possible in all kidney units. The renal tissue perfusion detected by LDF correlated excellently with the renal arterial blood flow under different renal perfusion pressures. The feasibility of using LDF probe to measure the renal tissue perfusion in a laparoscopic model was then assessed in 15 pigs. Under pneumoperitoneum, the right kidneys were approached transperitoneally with the animal in the decubitus position. A total of three trocars were used. The peritoneum and Gerota's fascia were incised and the LDF needle probe was manipulated and inserted by an endoforceps into the renal tissue via a 5-mm trocar. The insertion of the LDF needle probe was technically feasible in all 15 kidney units, and the depth of insertion could be adjusted under direct vision. Baseline values for the renal cortical and renal medullary blood flow were 50.1 +/- 17.7 and 8.8 +/- 3.3 ml/min/100 g tissue, respectively. Spatial variations of the LDF measurements averaged 6%, and temporal variations over 15 min averaged 5%. Four additional hemodynamic parameters were simultaneously recorded, including left carotid artery blood flow, aortic blood pressure, inferior vena caval pressure, and intraabdominal pressure. It appears that systemic and renal hemodynamic parameters can be monitored reliably and continuously in the porcine model. This method allows further information concerning hemodynamic changes and safety of laparoscopy to be obtained.

Animals↗
PubMed1996

Changes in urinary output and electrolytes during gaseous and gasless laparoscopy.

Urological laparoscopy has gained increasing acceptance recently. Alterations in renal water and electrolyte homeostasis by carbon dioxide peritoneal insufflation, retroperitoneal insufflation and abdominal wall lifting were measured in 30 well-hydrated pigs over a 2-h period. Oliguria was observed after gaseous insufflation but not alter lifting the abdominal wall. Return to normal urinary output was observed at 30 min after release of pneumoretroperitoneum, and 60 min after pneumoperitoneum. Creatinine clearance declined, while the clearance rates of potassium, sodium and urea remained unchanged during peritoneal and retroperitoneal insufflation. An elevated serum aldosterone concentration was found which may mediate the increased urinary excretion of potassium and decreased urinary excretion of sodium found during peritoneal insufflation. Renal function remained stable, despite an elevation of serum creatine kinase being elicited after lifting the abdominal wall. In conclusion, significant changes in water and electrolyte homeostasis occurred gaseous, not gasless, laparoscopy in pigs.

Animals↗
PubMed1996

Alterations in pulmonary function after retroperitoneoscopic surgery.

OBJECTIVE: To evaluate and compare changes in pulmonary function after retroperitoneoscopic and open surgery. PATIENTS AND METHODS: From June 1994 to October 1995. 11 patients (five men and six women, mean age 44.7 years, range 29-69) underwent retroperitoneoscopic procedures (Group 1) and 11 patients (eight men and three women, mean age 57.5 years, range 22-73) underwent flank-incision procedures (Group 2). The surgery comprised eight adrenalectomies and one each of nephroureterectomy, nephrectomy and pyelolithotomy in Group 1, and five adrenalectomies, four nephroureterectomies, one ureterolithotomy and one excision of a retroperitoneal tumour in Group 2. Pulmonary function tests (PFTs) were performed before and 3 days after surgery; the forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), forced expiratory volume at 25% (FEV25%), FEV1/FVC, vital capacity (VC), total lung capacity (TLC), residual lung volume (RV) and functional residual capacity (FRC) were compared between the groups. The post-operative changes in the PFTs were assessed using a paired t-test and the degree of change in both groups compared using the Mann-Whitney U-test. Other factors possibly influencing PFT were analysed using multiple regression. RESULTS: Pulmonary function was impaired in both groups on the third day after surgery. In Group 2, the FVC, FEV1, FEV25%, VC and TLC had declined significantly (all P < 0.05) from the pre-operative value. In Group 1, only the FVC and VC decreased significantly (P < 0.05). Post-operative pulmonary complications occurred in two patients in Group 2 but in none of those in Group 1, showing that pulmonary function was generally less affected in Group 1 than in Group 2. CONCLUSION: Although pulmonary function was impaired 3 days after surgery in both groups, retroperitoneoscopic surgery, by eliminating a large flank incision, caused less post-operative pulmonary dysfunction than open surgery.

Adult↗
PubMed1996

Laparoscopic ligation of bilateral spermatic varices under epidural anesthesia.

Feasibility and safety of laparoscopic ligation of bilateral internal spermatic varices under epidural anesthesia were assessed in 11 patients. Another 11 patients undergoing the same procedure under ventilation-assisted anesthesia served as controls. Patients in both groups belonged to the American Society of Anesthesia functional class I. Arterial blood analyses were obtained (1) in the horizontal supine position; (2) in the 15 degrees Trendelenburg position; (3) at 15 min after carbon dioxide pneumoperitoneum insufflation, and (4) at 15 min after desufflation in the supine position. In the epidural anesthesia group arterial blood parameters and respiratory rate remained stable in the Trendelenburg position. After intraperitoneal insufflation of carbon dioxide for 15 min, the arterial carbon dioxide level increased from 40.1 +/- 2.2 to 42.1 +/- 2.6 mm Hg, the respiratory rate increased from 17.0 +/- 1.4 to 20.6 +/- 1.2/min, the blood pH value decreased from 7.386 +/- 0.027 to 7.355 +/- 0.034, all values showing statistically significant differences. These changes returned to the preinsufflation level 15 min after release of the pneumoperitoneum. The above-mentioned parameters remained unchanged under the pneumoperitoneum by assisted ventilation in the control group. The mean time of surgery was similar in both groups: 82 and 90 min for the groups having general and epidural anesthesia, respectively. All laparoscopic procedures were accomplished successfully under general anesthesia. However, failure to ligate the internal spermatic varices occurred in 3 patients under epidural anesthesia, mainly due to patient intolerance to abdominal distension. The operation was continued under intubated general anesthesia for relaxing the abdominal muscle to provide an adequate working space. In 8 patients being successfully operated under epidural anesthesia, 5 experienced mild but tolerable abdominal distension; 2 complained of shoulder pain intraoperatively. Although laparoscopic ligation of internal spermatic varices could be accomplished in some patients under epidural anesthesia, it carried a high failure rate, more intraoperative morbidity, and significant arterial blood gas alterations. Routine ventilation-assisted anesthesia is suggested for therapeutic laparoscopy even for an easy procedure such as the ligation of the internal spermatic varices.

Anesthesia, Epidural↗
PubMed1996

Malakoplakia of the prostate forming a fistulous tract to rectum: a case report.

Malakoplakia is a rare lesion of granulomatous inflammation which mainly affects urinary bladder but may involve other parts of the body. Differentiation from neoplastic process is often difficult due to its tumorous gross appearance and similarity to carcinoma microscopically. Malakoplakia of the prostate is even rare. We present a case of prostatic malakoplakia masquerading as a rectal tumor due to formation of a fistulous tract to the rectal muscular layers accompanied with ulceration of the rectal mucosa. Its clinical course is different from those of most reported cases, while the outcome is as satisfactory as in usual cases.

Diagnosis, Differential↗
PubMed1995

Direct needle insufflation for pneumoretroperitoneum: anatomic confirmation and clinical experience.

OBJECTIVES: The feasibility and safety of direct needle insufflation to create pneumoretroperitoneum was assessed by an imaging study and clinical experience. METHODS: A total of 10 patients without previous retroperitoneal surgery or diseases received computed tomography scans of the retroperitoneum 2 cm above the iliac crest. Distances between quadratus lumborum and colon (Q-C distance) were measured in the supine and lateral positions. Changes of Q-C distance were calculated when the patient was changed from the supine to the lateral position. Operative charts on 38 retroperitoneoscopic procedures were collected prospectively to assess complications related to direct needle insufflation, which was performed by inserting a 14 G Veress needle blindly along the posterior axillary line 2 cm above the iliac crest. RESULTS: Q-C distance increased from 8.7 to 27.3 mm (left side) and 4.6 to 18.1 mm (right side) when the patient was changed from the supine to the lateral position, both P values < 0.05. An average distance of 23 mm between colon and quadratus lumborum was found when patients were lying laterally. The misplacement of a Veress needle was encountered in 1 patient, in which a prefascia insufflation resulted in conversion of the endoscopic procedure. Needle puncture caused no visceral or great vessel injury. CONCLUSIONS: Significant anterior movement of the colon was found when patients were changed from the supine to the lateral position. It provided a window for inserting the Veress needle blindly into the retroperitoneum. The high success rate (97%) and low complication rate of direct needle insufflation were found in actual clinical applications. We considered needle insufflation a safe and effective method of establishing a pneumoretroperitoneum for any retroperitoneoscopic procedure.

Adult↗
PubMed1995

Laparoscopic nephrolysis for chyluria: case report of long-term success.

Laparoscopic nephrolysis was performed in an 81-year-old man with recurrent chyluria. A total of five trocars were used for approaching the lymphatic ducts over the right ureter and renal hilum. The lymphatic ducts identified were easily ligated under laparoscopic magnification. The recovery of this patient was quick and uneventful. The follow-up urinalysis for chyle was negative, and his serum albumin concentration increased from 3.0 g/dL to 4.2 g/dL at 2 years postoperatively. This case report attests to the long-term efficacy of a laparoscopic approach to ligation of lymphatic fistulas for the treatment of recalcitrant chyluria.

Aged↗
PubMed1995

The impact of pneumoperitoneum, pneumoretroperitoneum, and gasless laparoscopy on the systemic and renal hemodynamics.

BACKGROUND: The use of therapeutic laparoscopy has become widespread recently. It is important to assess the effects of gaseous and gasless laparoscopy on systemic and renal hemodynamics. STUDY DESIGN: A prospective controlled animal study was performed on 40 well-hydrated pigs. Systemic and renal hemodynamics were monitored during peritoneal insufflation, retroperitoneal insufflation, and abdominal wall lifting for a period of two hours. A laser Doppler flow meter was applied laparoscopically to measure the renal cortical tissue perfusion. RESULTS: Peritoneal insufflation of carbon dioxide to a pressure of 15 mm Hg elicited transient elevations of the aortic pressure and carotid arterial blood flow. Unilateral pneumoretroperitoneum caused a smaller change on systemic hemodynamics. Pneumoperitoneum and pneumoretroperitoneum caused oliguria. Superficial renal cortical blood flow reduction decreased by an average of 60 percent in the compressed kidney, and blood flow returned to the pre-insufflation level after the pressure was released. A gradual decrease of tissue perfusion in the contralateral kidney and a concomitant gradual increase of the intra-abdominal pressure were observed when pneumo-retroperitoneum was maintained for two hours. No significant changes in urinary output and in systemic and renal hemodynamics were found when the abdominal wall was lifted up with a force equivalent to 15 mm Hg. CONCLUSIONS: Significant systemic and renal hemodynamic changes were elicited in gaseous but not in gasless laparoscopy, which may explain the decreased urinary output observed during gaseous laparoscopy. Pneumoperitoneum caused greater systemic and renal hemodynamic alterations than pneumoretroperitoneum; however, the effects were transient and reversible after a period of two hours.

Animals↗
PubMed1994

Effects of intra-abdominal pressure on renal tissue perfusion during laparoscopy.

An animal model was established to study the effects of elevated intra-abdominal pressure (IAP) on systemic and renal hemodynamics during laparoscopy. In a pilot study in five dogs, we simultaneously recorded carotid artery blood flow (CABF), carotid artery blood pressure (CABP), inferior vena caval pressure (IVCP), renal parenchymal blood flow, and IAP. The renal parenchymal blood flow was measured by a laser Doppler flowmetry (LDF) needle probe and the renal artery blood flow by an ultrasonic Doppler probe, both placed through laparotomy. The reliability and reproducibility of these two measurements at different renal perfusion pressures were documented. The established method was then used to assess the effects of increased IAP on renal hemodynamics during laparoscopy in six pigs. Pneumoperitoneum was achieved by insufflating the abdominal cavity with air. The LDF needle probe was inserted into the renal parenchyma laparoscopically. An increase in IAP from 0 to 40 mm Hg did not influence CABP. However, significant decreases in CABF were seen from 190.8 +/- 59.5 mL/min at 0 mm Hg IAP to 169 +/- 43.6 mL/min at 15 mm Hg. The CABF decreased in a linear fashion as IAP was increasing (correlation coefficient R = 0.976). Renal cortical blood flow (RCBF) decreased from 50.1 +/- 17.7 mL/min per 100 g at 0 mm Hg to IAP to 21.2 +/- 9.6 mL/min per 100 g of tissue at 15 mm Hg. There was an exponential correlation between IAP and RCBF (R = 0.897).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1993

Deoxyribonucleic acid histogram of testes in primary transsexualism.

The influence of oestrogen on spermatogenesis was evaluated by comparing its effect on the testes of primary male transsexuals and those who had undergone hormone therapy for prostatic carcinoma. Eight primary transsexuals were studied. They had been diagnosed on clinical and psychiatric evidence and had been on oestrogen therapy for several years since puberty. Histological sections of testicular tissue obtained at reassignment surgery from 8 phenotypic male transsexuals (aged 24-32 years) with an XY chromosome complement were studied by light microscopy. The formalin-embedded specimens were analysed by flow cytometry for deoxyribonucleic acid (DNA) histograms. Both the histology and DNA histograms revealed a pattern of maturation arrest in 12 of 16 testes in which the diploid cell compartment occupied most of the spermatogenetic element, followed by tetraploid and monoploid cells. Two testes showed impaired spermatogenesis and 2 were normal. The DNA histograms and pathology were also evaluated in 20 testes after 3 to 8 years of hormone therapy in patients with advanced prostatic carcinoma (aged 60-78 years). No maturation arrest was found in these patients. Sixteen of them had a pattern of fibrosis and atrophy and 4 had impaired spermatogenesis. It was concluded that oestrogen influenced spermatogenesis and affected the maturation of spermatogonia mostly during puberty.

Adult↗
PubMed1993

Retraction notice.

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Retraction Notice↗
PubMed1993

Flow cytometric study of anterior chamber aqueous humor after neodymium: yttrium aluminum garnet laser iridotomy.

Laser iridotomy is a safe and effective treatment of pupillary-block glaucoma; however, increased intraocular pressure (IOP) may occur after the procedure. A flow cytometric study of aqueous humor was done 1.5 hours after neodymium: yttrium aluminum garnet laser iridotomy in 20 eyes. This sensitive and precise method did not reveal an apparent correlation between the degree of postoperative IOP spike and the amount of inflammatory cells or cellular debris induced by laser iridotomy. Although slit-lamp examination showed many "cells" in the anterior chamber in most after laser iridotomy, DNA histography found only scanty chromatin coating cells. We believe the so-called cells observed using slit-lamp biomicroscopy might not all be real cellular aggregates but rather aggregates of protein or fibrin in some situations.

Acute Disease↗
PubMed1992

Laparoscopic ligation of internal spermatic vein.

Laparoscopic procedures have long been a standard form of treatment for gynaecological disorders but have only recently shown promise in the evaluation and treatment of urogenital diseases, such as pelvic lymphadenectomy. We performed laparoscopic ligation of the bilateral internal spermatic veins in 15 male pigs. The average operative time was 20 min and operative morbidity was minimal, comprising mild subcutaneous emphysema around the trocars. Engorgement of the spermatic vein proximal to the endoclip site was noted. There was no operative mortality. Laparoscopic ligation of the internal spermatic veins seems to be a feasible method for the treatment of varicoceles, especially bilateral lesions.

Animals↗
PubMed1992

Laparoscopic nephrectomy in a porcine model.

Laparoscopic nephrectomy was performed in 15 male pigs, the procedure was successful in 14. Extraction of the intact kidney through a 5-cm lower abdomen incision was done in 7 animals; complete destruction and evacuation of the kidney was accomplished by a round-knife suction device through a 1-cm port in another 7 pigs. Grossly, the specimen consisted of sausage-like tubular renal tissue and a small amount of tissue debris. Pathology revealed that the glomerular and tubular structures were well preserved, no interstitial hematoma could be found. Four ports were usually used, one 1-cm umbilical camera port, one 0.5-cm port for ureter traction, and two 1-cm working ports along the midclavicular line. All the pigs recovered uneventfully. The average operation time was 3 h 20 min. The application of endo-GIA (United States Surgical Corporation) for renal hilum reduced the operative time to 2 h 20 min. Complications included renal vein tear during endoclip application and cutting in the first case, mild subcutaneous emphysema in 2 cases. This first pig received exploratory laparotomy for the repair and ligation of the renal vein. No more major complications occurred with increasing experience. From this porcine experiment, we conclude that the combination of laparoscopy, a tissue destroyer and an endobag for the entrapment of kidney seem to be a promising technique for clinical nephrectomy.

Animals↗