Biomedical subjects
Publications and source records attributed to R Chang.
Newer endoscopic techniques derived from percutaneous renal manipulations are well suited for endoscopic reconstruction of traumatic short total membranous urethral transections. Four men and 1 child underwent successful endoscopic membranous urethral reconstruction. All 4 men are voiding with good flow and normal control more than 1 year after any endoscopic manipulation.
The percutaneous methods of management of benign ureteral strictures or fistulas have developed as a natural evolution of percutaneous nephrostomy and angiographic techniques. We review our 5-year experience, which includes 18 patients with 19 benign ureteral strictures and 12 patients with ureteral fistulas. In the majority of the patients the ureteral strictures occurred at sites of surgical reconstruction or endoscopic manipulation. All fistulas resulted from surgical injury. In 10 of the 12 patients (82 per cent) the fistulas healed without development of a stricture or need for further intervention. Patients with short ureteral strictures had a high incidence of success and they usually were the best candidates for percutaneous manipulation. The long strictures usually were of longer duration and they were less likely to be managed successfully percutaneously. Failure of percutaneous dilation did not impede subsequent surgical management. Percutaneous management often is a reasonable initial step in the treatment of ureteral strictures and fistulas.
Ureteroscopy is an important technique in the management of calculous disease and ureteral lesions but it appears to have a greater potential for injury than percutaneous nephroscopy. In 2 years 4 patients with severe ureteroscopic injuries were treated. In 3 patients complete obstruction of the ureter occurred, and 1 had a major ureteral tear, prolonged urinary extravasation and infection. Even in the presence of total ureteral occlusion patients with short strictures were managed successfully percutaneously but the 2 patients with longer strictures were not. Previous surgery on the ureter or pelvic surgery and radiation therapy appear to be negative factors that affect adversely the ureteral blood supply, and potentiate poor healing and scarring. Nephrostomy tube drainage and ureteral stenting after ureteral dilation appear to be important steps in the percutaneous management of these patients.
Analysis of 193 femoropopliteal angioplasties demonstrated patency rates in the stenotic group of 75.5% at 6 months and 54.4% at 54 months. The patency rates for the occlusive group were 93.7% at 6 months and 72.9% at 54 months; these rates were significantly better than those in patients with stenoses. A group of 14 patients with long-segment (greater than 7 cm) stenosis had the highest risk of early failure, with a 6-month patency of 23.1%. After removal of the long-segment stenosis group from the results, there were no significant differences between the long-term patencies for stenotic and occlusive lesions. If angioplasty of long stenoses is attempted, a high initial success rate but early failure should be anticipated.
Angiographic ablation of parathyroid adenomas with ionic contrast material was performed in 24 patients with persistent hyperparathyroidism who had undergone at least one prior unsuccessful surgical resection; 23 had mediastinal adenomas. The success rate was 83% at 1 month after ablation and 71% at both 5 and 9 years. Ablation was successful in 85% of the patients in whom the catheter could be wedged into the artery feeding the adenoma. Long-term success was achieved in 89% of the patients in whom contrast enhancement persisted in the adenoma on computed tomographic scans obtained 24 hours later. Acute complications were seen only in patients with glands supplied by the inferior or superior thyroid arteries. Long-term complications were limited to permanent hypocalcemia, present in 8% of patients. Even if unsuccessful for ablation, the procedure may provide localization and does not preclude surgical resection. It is recommended for most patients with persistent hyperparathyroidism and mediastinal adenomas, especially adenomas supplied by the internal thoracic artery.
A prospective, blinded comparison of three methods of hepatic contrast enhancement in computed tomography (CT) was conducted in 15 patients with colorectal carcinoma metastatic to the liver. Arterial portography (AP-CT) was performed with injection of contrast material into the superior mesenteric artery during CT. Delayed scanning (DS-CT) was performed 4 hours after intravascular administration of contrast material (mean dose, 280 mL). CT with an ethiodized oil emulsion (EOE-CT) was performed 1 hour after slow intravenous infusion of the emulsion. All patients underwent laparotomy following imaging studies. A lesion-by-lesion analysis of 56 metastases showed no significant differences in sensitivity (AP-CT, 77%; DS-CT, 83%; EOE-CT, 82%), but the false-positive rate for AP-CT was significantly higher than that for DS-CT (P less than .001) or EOE-CT (P less than .01). False-positive rates for EOE-CT and DS-CT were not significantly different. The predictive value of a positive test was 63% for AP-CT, 90% for DS-CT, and 81% for EOE-CT. AP-CT does not appear to be clinically useful for detection of hepatic metastases because of the high false-positive rate. No difference could be demonstrated between DS-CT and EOE-CT. DS-CT is a valuable method for hepatic contrast enhancement.
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Sixty-one renal transplant patients were studied for ocular complications of steroid therapy. Twenty patients (32.8%) were found to have posterior subcapsular cataract. Three patients (4.9%) had ocular hypertension. There was no significant correlation between cataract formation and the total dose of steroids, number of rejection episodes, or the period of hemodialysis. HLA-A9 was present in noncataract patients to a greater extent, a statistically significant (P less than .05) finding not reported before to our knowledge.
Chymodenin, a hormone-like duodenal peptide which rapidly alters the proportions of secreted pancreatic digestive enzymes to a mixture relatively richer in chymotrypsinogen than that found in basal secretion, has been purified to homogeneity. The starting material was an acidic methanol-soluble, neutral pH-insoluble fraction of an acetic acid extract of porcine duodenum; the purification consisted of cation-exchange chromatography on SP-Sephadex and CM-Sephadex in ammonium bicarbonate gradients, and gel filtration on Sephadex G-75 in dilute acetic acid. The yield of material was followed by radioimmunoassay. Homogeneity was determined from chymodenin's behavior in disc gel electrophoresis in an acidic counter-migration-of-dye system, sodium dodecyl sulfate-urea gels, gel filtration, dansyl-Edman reaction, reversed-phase high pressure liquid chromatography, isotachophoresis, and sedimentation equilibrium ultracentrifugation. The electrophoretic mobility, the molecular weight of 9,000-10,000, and the biological activity differed from those of other gastrointestinal peptide hormones. The amino acid composition was unique. Chymodenin is the first purified hormone-like substance reported capable of altering the composition of the mixture of secreted digestive enzymes, independent of the stimulation of massive pancreatic protein output.
Venography to evaluate the patency of upper-extremity veins was performed with digital subtraction angiography (DSA) and conventional angiography. Venous thrombosis was easily diagnosed, and the innominate veins and superior vena cava were more easily visualized using DSA. Iodine concentration for DSA was one-third that of conventional venography, and the examination time was reduced by 50% using DSA. Patient comfort and acceptance were greater with DSA. DSA is a superior technique for upper-extremity vein evaluation in cooperative patients.
To ascertain radiation exposure to medical personnel during percutaneous nephrolithotomy, lithium fluoride thermoluminescent dosimeters (TLDs) were utilized for the radiographic monitoring of 7 consecutive patients. Average fluoroscopy time per procedure was 27.8 minutes of which 15.1 minutes were for nephrostomy tube insertion and 12.7 minutes were for calculi extraction. The 2 radiologists received 4.5 and 5.1 mrad per procedure, while the 2 urologists received 2.5 and 3.7 mrad. All other ancillary personnel received less than 2.1 mrad per procedure except the anesthesiologists whose mean exposure was 4.7 mrad. By taking appropriate precautions and using the proper equipment, percutaneous nephrolithotomy can be performed with a low level of radiation exposure for all involved physicians and personnel.
Although partial nephrectomy for renal cell carcinoma has been recommended for tumors in solitary kidneys, surgical enucleation has been suggested as an alternative form of surgical management in highly selected patients. To verify the efficacy of surgical enucleation the surgical specimens from 16 standard radical nephrectomies were dissected carefully. The tumors were enucleated ex vivo and carefully investigated pathologically. It was possible to enucleate successfully some well circumscribed, low grade tumors but venous invasion, tumor heterogeneity, occult metastatic disease in lymph nodes, satellite tumor nodules in the kidney and extrinsic spread through the renal capsule were features that may not have been appreciated fully in the operating room. Computerized tomography could not always predict which patients were possible enucleation candidates. Partial nephrectomy remains the preferred surgical treatment in a parenchymal-sparing operation rather than simple enucleation.
Venography of 44 recurrent varicoceles in 37 patients demonstrated different anatomical patterns of recurrence in surgical patients (26) compared to those treated by percutaneous balloon occlusion (18). The 3 types of patterns identified included parallel, renal vein and transcrotal collateral pathways. Virtually all surgical recurrences were owing to mid retroperitoneal (27 per cent) or low (inguinal) parallel collaterals (58 per cent). The majority of post-balloon occlusion recurrences were due to either high retroperitoneal parallel (44 per cent) or renal vein collaterals (28 per cent). Surgical recurrences were treated easily with percutaneous balloon occlusion. However, 39 per cent of the patients with recurrences following balloon embolization were not anatomical candidates for repeat percutaneous occlusion. We conclude that venous collaterals are identified easily by renal venography, and knowledge of these collaterals is helpful in planning further surgical or radiological treatment.
Among 227 patients undergoing outpatient balloon embolotherapy for varicocele, venography of the right internal spermatic vein (ISV) was attempted in 48. A percutaneous technique from the right femoral vein was used for all patients. The right ISV was successfully occluded with detachable balloons in 41 of 46 (89%), while in five (11%), the right ISV could not be embolized. A competent valve was found in two patients. The right ISV alone was embolized in ten patients: one had a solitary right varicocele, six had left varicoceles but competent valves in the left ISV, and three had recurrent left varicoceles after successful left ISV occlusion. Bilateral ISV embolization was achieved in 31 patients. Long-term follow-up study was available for 25 patients; 12 couples (48%) achieved a pregnancy. Percutaneous balloon occlusion of right varicoceles is a safe, effective outpatient technique.
A simple method of measuring vessel diameters using intraarterial digital subtraction angiography has been designed. With a catheter in place within the vessel of interest, a segmented guide wire with known dimensions is advanced into the catheter in the area to be measured. We have used the method successfully for balloon angioplasty as well as balloon embolization.
Short-term results of superficial femoral artery and popliteal percutaneous transluminal angioplasty have been good, but long-term results and factors influencing long-term patency are less commonly reported. One hundred thirty-seven superficial femoral artery angioplasties with follow-up for 54 months were reviewed. The 4-year patency for stenoses was 61% and for occlusions was 68%. If the initial result was clinically successful, the 4-year patency was not influenced by the quality or patency of runoff or by the length of the occlusion. Nineteen patients returned for redilatation, eight of whom had developed new lesions. Patency was adversely affected in patients with diabetes or with long-segment stenoses. Modifications of equipment and technique that may improve long-term patency rates are discussed.
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