A general ureteral dilator-sheathing system.
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Catheterization↗
Biomedical subjects
B Finlayson
Publications and source records attributed to B Finlayson.
EQUIL2: a BASIC computer program for the calculation of urinary saturation.
A BASIC computer program for the calculation of urinary supersaturation with respect to the common kidney stone components is described. In vitro and in vivo tests show that the program described accurately calculates supersaturation. The application of this computer program to urolithiasis research is discussed.
Computers↗
Retrograde nephrostomy and percutaneous calculus removal in 30 patients.
We used a new technique, retrograde nephrostomy, to provide intrarenal access for percutaneous calculus removal in 30 consecutive patients. Under fluoroscopic control, we maneuvered cystoscopically a 5F and 9F coaxial catheter pair over a guide wire into the calix selected for nephrostomy. Then, a sheathed 20 to 21 gauge needle was passed through the 9F catheter into the flank to create the nephrostomy. Eight patients were given general and 22 intravenous sedation and local anesthesia for nephrostomy placement and calculus removal. Retrograde nephrostomy and subsequent calculus removal were completed successfully in 90 and 83 per cent of the 30 patients, respectively. There were 6 complications and 3 failures among the first few patients due to inferior equipment and inexperience with the technique. Over-all, we found that retrograde nephrostomy provided reliable, precise intrarenal access and we believe that it could become an alternative technique to aid in percutaneous calculus removal procedures.
Adult↗
Renal morphology and function immediately after extracorporeal shock-wave lithotripsy.
The acute effects of extracorporeal shock-wave lithotripsy (ESWL) on morphology and function of the kidney were evaluated by excretory urography, quantitative radionuclide renography (QRR), and magnetic resonance imaging (MRI) in 33 consecutive patients. Excretory urograms demonstrated an enlarged kidney in seven (18%) of 41 treatments and partial or complete obstruction of the ureter by stone fragments after 15 (37%) of 41 treatments. Total effective renal plasma flow (ERPF) was not changed after ESWL, but the percentage ERPF of the treated kidney was decreased by more than 5% in 10 (30%) of 33 cases. QRR images showed partial parenchymal obstruction in 10 (25%) of 41 treated kidneys and total parenchymal obstruction in 9 (22%). MRI disclosed one or more of the following abnormalities in 24 (63%) of 38 treated kidneys: (1) loss of corticomedullary differentiation, (2) perirenal fluid, (3) subcapsular hematoma, (4) hemorrhage into a renal cyst, and (5) unexplained abnormalities. Treated kidneys were normal by all three imaging methods in 26% and abnormal by one or more tests in 74% of cases. The morphologic and functional changes are attributed to renal contusion resulting in edema and extravasation of urine and blood into the interstitial, subcapsular, and perirenal spaces.
Humans↗
Relationship between experimentally induced crystalluria and relative supersaturation of various stone salts in rats.
Calcium oxalate crystalluria was induced in laboratory rats by subcutaneous implantation of potassium oxalate containing mini-osmotic pumps in their intercapsular region. Concentrations of major urinary ions were measured and urinary supersaturations of various urinary salts were calculated using a computer programme. The urines of experimental animals that received oxalate had calcium oxalate crystals and higher supersaturations for calcium oxalate compared to their controls. Oxalate levels of the urines of experimental animals were higher than their controls and this increase was proportional to the increase in urinary supersaturation of calcium oxalate. No significant difference was found in the calcium levels of urines from experimental and control animals.
Animals↗
Renal papillary changes in patient with calcium oxalate lithiasis.
We report the case of a white woman with bilateral renal calculi that were removed by bilateral nephrolithotomies. The morphology of renal tubular stones and the changes in papillary tissue were studied by light microscopy and scanning and transmission electron microscopy. The stones were made of calcium oxalate and were intratubular. Large calcium phosphate deposits were present in the interstitium. There was a marked interstitial fibrosis and tubular epithelial hyperplasia.
Calcium Oxalate↗
Hemorrhage from congenital renal arteriovenous malformation in pregnancy.
A case report of life-threatening hemorrhage from a congenital renal arteriovenous malformation during pregnancy is presented. The hyperdynamic circulatory state that exists during pregnancy may predispose to bleeding from vascular malformations. We review the classification and clinical presentation of renal arteriovenous malformations.
Adult↗
New steerable catheter for use in percutaneous nephrolithotomy.
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Catheterization↗
Crystal retention by injured urothelium of the rat urinary bladder.
Injuries caused by hydrochloric acid or Triton X 100 application to the rat bladder urothelium, and the effects on calcium oxalate crystal retention, were examined by light and scanning electron microscopy. Damage due to either compound resulted in desquamation of urothelial cells. The crystals appeared to be retained by a fibrillar material, some of which was identified as fibrin. Heparin treatment of injured urothelium was found to prevent crystal retention.
Adhesiveness↗
Dissolution kinetics of uric acid calculi.
Dissolution of uric acid calculi was studied in vitro. Calculated rate constants were then applied to an in vivo situation. The time required for complete dissolution of a uric acid calculus in a patient on oral alkali therapy can be estimated. Sodium bicarbonate, acetylcysteine, [tris(hydroxymethyl)aminomethane] and [tris(hydroxymethyl)aminomethane]-E were tested for relative effectiveness in dissolving uric acid calculi in vitro. In patients who require irrigation for dissolution of uric acid calculi [tris(hydroxymethyl)-aminomethane] is the preferred agent.
Acetylcysteine↗
Calcium oxalate retention in subjects with crystalluria.
Calcium oxalate retention was studied in non-stone-forming volunteers. All subjects were placed on a constant diet for 5 days. After the oral administration of 10 microCi of [14C]-oxalic acid, the pattern of urinary oxalate excretion was followed for 48 h. Each subject was then given 10 microCi of [14C]-oxalic acid mixed with sufficient sodium oxalate (7.5 mg/kg body weight) to induce calcium oxalate crystalluria. Urinary oxalate excretion was then recorded for 48 h. After the administration of labeled oxalic acid (without additional sodium oxalate), 76.6 +/- 5.9% of the total recovered dose was excreted by 4 h. When the labeled oxalic acid was mixed with a sodium oxalate load, 62.4 +/- 8.8% was excreted by 4 h (p less than 0.01). Induction of calcium oxalate crystalluria results in the retention of oxalate in the kidney. The degree of retention varies among individuals. Differences in particle retention may help explain the differences between stone formers and non-stone formers.
Adult↗
Retrograde nephrostomy for stone removal: combined cystoscopic/percutaneous technique.
The retrograde percutaneous nephrostomy, a new technique for access to the urinary tract for stone removal, involves cystoscopic placement of a 9 French catheter into a selected minor calix, through which a sheathed 20- or 21-gauge needle is then advanced to exit at the skin. The tract is then dilated over this needle. This technique has been used successfully in 38 patients with only three complications. The technique is more reliable and less time-consuming than the standard antegrade percutaneous approach, particularly in the nondilated pelvicaliceal system. However, to avoid damage to the liver, spleen, or pleural cavity, care must be taken to ensure that the needle does not exit in a cranial direction.
Cystoscopy↗
Extracorporeal shock-wave lithotripsy.
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Electricity↗
Mechanisms of stone formation--an overview.
We have compiled a broad overview of the genesis of urinary stones. Central to the theses given are precise definitions of stone as opposed to stone disease. In terms of mechanisms, a kinetic point of view is essential to any formulation relating to stone formation. It is necessary to comprehend the kinetic approach, an understanding of nucleation, growth and aggregation, if one is to appreciate the final product--the stone. Certain fundamental concepts are reviewed which are critical in grasping these phenomena. Not to be forgotten is that the purely physical chemical aspects of stone formation are insufficient to explain all facets of the process. Therefore, interactions between crystals and tissue are explored in suggesting a unifying hypothesis for upper tract stone disease.
Adhesiveness↗
Management of the stone former.
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Allopurinol↗
Experimental induction of crystalluria in rats using mini-osmotic pumps.
Crystalluria was induced in male Sprague-Dawley rats by implanting potassium-oxalate-containing mini-osmotic pumps. Urine of all experimental animals had abundant crystals of calcium oxalate, hydroxypatite, struvite, and calcium phosphate. These crystals were similar in morphology to the crystals found in human crystalluria. Histological examination of kidneys and tissue samples from other organs revealed no abnormality. One group of animals was injected with sodium oxalate in addition to implantation of potassium-oxalate-containing mini-osmotic pumps. Bladder urine from these animals contained calcium oxalate microstones and their kidneys had deposits of calcium oxalate crystals.
Animals↗
New monofilament basket for bladder calculi.
Successful stone manipulation was facilitated with the new monofilament basket in experimental situations and in patients. Advantages over other baskets include: in vivo adjustability, reduced mucosal trauma, ability to irrigate and aspirate through the basket, and ability to pass lithotriptor electrodes within the basket. Basket modifications under study might prove useful within the ureter, renal pelvis, and biliary tree.
Animals↗
Hawkins-Hunter retrograde transcutaneous nephrostomy: a new technique.
Retrograde nephrostomy, a new technique to aid in stone management, has been performed successfully in dogs. It has also been used without complication in a human patient to help remove a renal stone percutaneously under local anesthesia. The technique consists of placing a coaxial catheter over a guidewire under fluoroscopy into the exact calyx desired and advancing a long needle out to the skin to establish a transcutaneous tract. The advantages of the technique include increased control and precision of tract placement, efficient working angles for percutaneous stone removal, and the ability to perform the procedure under local anesthesia.
Animals↗