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Biomedical subjects

R Hohenfellner

Publications and source records attributed to R Hohenfellner.

At least 145 records · Page 8Linked to original sources
PubMed1992

Seven years experience with the Mainz pouch procedure.

In 1983 we created a form of continent urinary diversion termed the Mainz pouch procedure utilizing cecum and ileum. For creation of the reservoir 10 to 15 cm of cecum and ascending colon as well as two terminal ileal segments of equal length are isolated and detubularized. The posterior wall of the pouch is completed by anastomosis of the ascending colon with the terminal ileal loop starting at the inferior aspect. The latter is then anastomosed with the next proximal ileal segment. The ureters are implanted in an antirefluxive manner in the open end technique through a submucosal tunnel of 4 to 5 cm of length. For bladder augmentation the pouch is anastomosed to the bladder remnant. For bladder substitution a buttonhole incision at the most inferior aspect of the cecal pole or the appendix is used for end-end anastomosis to the membrancus urethra. For continent diversion and additional 8 to 12 of ileum are isolated in order to create an ileal intussuscepted valve. Alternatively the appendix can be used. Continence is achieved by submucosal embedding of the appendix into the cecal pole. A total of 281 patients underwent the Mainz pouch procedure, 54 for bladder augmentation, 7 for bladder replacement and 200 for continent urinary diversion. We encountered early complications in 15 of the 281 patients (5.3%). Late complications were observed in 63 patients (22.4%). The major complications we encountered were stone formation inside the pouch in 17 patients and stomal stenosis in 19. Fifty-two of the 54 patients with a bladder augmentation are completely continent (mean follow-up: 50 months, range: 10 to 83 months). All of the 27 patients who received a bladder substitution after radical cystectomy are continent during daytime. Three of these patients who do not empty their bladder at regular four hour intervals have leakage during the night (follow-up: 23 to 69 months). The revision rate due to nipple gliding and subsequent incontinence could be greatly reduced by the use of staples for fixation of the ileal nipple and the use of the appendix. For correction of the most frequently occurring complications standardized techniques have been developed.

Cecum↗
PubMed1991

Characterization of conservatively resected renal tumors using automated image analysis DNA cytometry.

The DNA histograms of 57 conservatively resected renal tumors were studied using automated image analysis DNA cytometry (Leytas II). Forty-nine of the analyzed tumors were renal cell carcinomas, six were oncocytomas, one was an angiomyolipoma, and one was a renal cell adenoma. On the basis of their DNA histograms, diploid, tetraploid, and aneuploid tumors could be distinguished. Aneuploid tumors could be subtyped further according to the DNA content of the stem cell line as hyperdiploid, hypertriploid, or hypertetraploid. Eight of the tumors were characterized by a combination of diploid and hypertriploid stem cell lines. During a mean follow-up of 5 years, only the two patients with a pure hypertriploid tumor died of distant metastases. These results indicate that automated DNA image analysis cytometry is able to differentiate among several types of renal tumors with obviously different prognoses.

Adenoma↗
PubMed1991

[Organ-preserving surgery of renal cell carcinoma. The surgical technic, results and complications].

Operative method, course and complications were analysed retrospectively in 120 patients in whom a kidney tumour had been resected without nephrectomy. In 49 patients (18 women and 31 men, mean age 59 [38-77] years; 45 renal-cell carcinomas, 4 benign renal tumours) there was an "imperative indication" for an organ-preserving operation, because nephrectomy would have made dialysis obligatory. In 74 patients with a healthy contralateral kidney (25 women, 49 men, mean age 55 [31-74] years; 61 renal-cell carcinomas, 13 benign tumours) the tumour was enucleated by choice; 55 of these patients were symptom-free. 36 of 49 patients with an imperative indication are without sign of tumour progression after a mean follow-up period of 4.5 years. In two there was a recurrence after 4 and 5 years, respectively, requiring a second organ-preserving operation. Known metastases were present in 3 of 6 patients who died of their tumours. 68 of 74 patients operated on electively are without signs of tumour progression after a mean follow-up period of 3.3 years. One patient died from tumour metastases. Two patients had tumour recurrence, requiring nephrectomy and enucleation, respectively.

Adult↗
PubMed1991

CO2 and Nd:YAG laser systems in microsurgical venous anastomoses.

A comparative study was undertaken in 81 rats to investigate a CO2 and Nd:YAG laser system for laser-welded anastomosis of the femoral vein. Conventionally sutured anastomoses (CMSA) served as controls. Laser-welded anastomosis (LAMA) was easier and could be performed 30% faster than CMSA. Postoperative investigations included patency tests, postmortem examinations and light and electron microscopy. Aneurysms were not seen. Foreign-body reaction was more pronounced in CMSA. Patency rates for CO2-LAMA and CMSA were equal, whereas Nd:YAG-LAMA resulted in significantly higher rate of early postoperative thrombosis (P less than 0.01). Because of its physical properties, the CO2-laser system seems to be better suited for laser welding of delicate structures such as the rat femoral vein.

Anastomosis, Surgical↗
PubMed1991

Surgical aspects of urolithiasis in children.

Operative management of renal calculi has changed radically in the last decade. New operative techniques, the use of intra-operative ultrasound and Doppler sonography have even made possible the removal of complete staghorn calculi in short and kidney-preserving procedures. The introduction of percutaneous nephrolithotomy and stone extraction using a specially designed ureteroscope and, above all, the clinical application of extracorporeal shock wave lithotripsy have made stone surgery less invasive and have provided a higher rate of preservation of kidney function.

Endoscopy↗
PubMed1991

The nutcracker syndrome: new aspects of pathophysiology, diagnosis and treatment.

Magnetic resonance imaging (MRI) was used to study vascular anatomy in 3 patients with the nutcracker syndrome and in 10 healthy volunteers. From these studies an abnormal branching of the superior mesenteric artery from the aorta was identified as being the cause of the nutcracker syndrome. Consequently, surgical transposition of the left renal vein to achieve an unobstructed renal venous backflow was performed successfully in 2 patients, while 1 underwent nephrectomy. In 1 patient adjuvant ureteral instrumentation became necessary to aid occlusion of persisting shunts between peripelvic venous varicosities and the urinary tract. Awareness of the pathophysiology of the nutcracker syndrome ensures an early diagnosis, which should be confirmed by a combination of diagnostic procedures, including MRI.

Adult↗
PubMed1991

Extracorporeal shock wave lithotripsy of urinary calculi: experience in treatment of 3,278 patients using the Siemens Lithostar and Lithostar Plus.

Between March 1986 and June 1989, 3,278 patients with upper urinary tract calculi were treated at our medical center with the Lithostar lithotriptor. The stones were located in the calices in 41.9% of the cases, renal pelvis in 25.7% and ureter in 32.4%. Perirenal hematoma was noted in 0.5% of the patients but this resolved spontaneously within a few days. Auxiliary procedures were performed in 37.3% of the cases, including Double-J stent and ureteral catheter in 26.8%, ureterorenoscopy in 2.1%, percutaneous nephrostomy in 1.6%, Zeiss loop in 4.3% and percutaneous nephrolithotripsy in 3.5%. Of the treatments 83.1% were performed without general or regional anesthesia. Followup after 3 months showed a 63.8% rate free of stone. The Lithostar upgraded with the overhead lithotripsy module is called Lithostar Plus. A total of 25 patients with upper urinary stones underwent treatment with the overhead module. Initial experience revealed fragmentation of stones after the first session in 20 patients, while a second session was necessary in 5. Analgesic sedation was used in 4 patients in whom a Double-J stent was inserted.

Endoscopy↗
PubMed1991

Bursting strength of the rat aorta: comparison of suture and laser anastomoses.

The bursting strength of sutured and laser-welded vascular anastomoses were assessed in a rat aorta model. Postoperative investigations included postmortems, light and scanning electron microscopy and measurements of bursting strength at set intervals (30 min, 3, 14 and 28 days postoperatively, p.o.). Laser-bonded anastomoses consistently demonstrated lower bursting strengths than suture controls, with statistically significant differences at 30 min and 3 days p.o. (p less than 0.01). Laser anastomosis was easier and faster to perform, the foreign body reaction was markedly lower than in sutured controls. Formation of aneurysms was not observed.

Anastomosis, Surgical↗
PubMed1991

Long-term follow-up of children with surgically treated vesicorenal reflux: renal growth.

Renal growth after successful surgical correction of vesicoureterorenal reflux (VUR) in childhood was observed in 137 female and 22 male patients over a mean follow-up period of 10.5 years. The renal parenchymal area was determined using a compensatory planimeter. For each measured value, the standard deviation score (SDS) was calculated by comparison with a normal population. On average, renal growth after reflux operation nearly paralleled the expected normal growth rate. Scarred kidneys had a worse growth prognosis than refluxing renal units (RU) without renal damage, growth retardation being correlated with the degree of pyelonephritic changes. The diminished growth rate of scarred kidneys was accompanied by a compensatory growth of the contralateral kidney. In the absence of renal scars, a modest tendency toward growth retardation was seen in kidneys with previously high degrees of VUR. In 39.7% of the unscarred RU with an initial SDS less than -0.5, accelerated growth (change in SDS of 0.5 or more) was observed. Accelerated growth was most accentuated on small unscarred kidneys (initial SDS less than -2.0).

Adolescent↗
PubMed1991

Pyelotransverse pyelocolostomy: an alternative method for high urinary diversion in patients with extended bilateral ureter damage.

After previous radiation due to pelvic malignoma or after multiple operations, the ileal conduit as well as sigmoid conduit are associated with an increased rate of complications. In these patients, the middle and distal ureter often cannot be considered for reimplantation due to fibrosis. High anastomosis to a bowel segment which is undamaged proves favorable. The transverse colon, conveniently situated in the cranial abdomen, is close enough to the kidneys for such a high anastomosis and is mostly spared from irradiation. In cases where severely damaged ureters forbid connection to a normal transverse conduit, we performed a pyelotransverse pyelocolostomy with high anastomosis of the bowel to both renal pelves or ureteropelvic junctions. 7 patients have been treated in this way and the follow-up of these patients ranges between 14 and 24 months. Postoperatively increased renal function was found in 6 renal units, stable function in 6 renal units, and only 1 patient showed a functional ureteropelvic stenosis. 4 months after the operation 1 patient died of sepsis caused by recurrent urinary tract infections due to recurrent stone disease as a consequence of immobilization in myelomeningocele. In patients with nearly total loss of ureters the pyelotransverse conduit is an effective surgical solution and may prove more comfortable to the patient than bilateral percutaneous nephrostomies.

Adult↗
PubMed1991

Long-term experience with conservative surgery of renal tumors. Surgical technique, complications, results, DNA-cytometry.

The surgical technique, course and complications were analysed in 123 patients in whom a kidney tumor had been enucleated. Fifty-seven enucleated tumors were available for image analysis DNA-cytometry. In 49 patients there was an imperative indication for an organ-preserving operation, because nephrectomy would have made dialysis obligatory. In 74 patients with a healthy contralateral kidney the tumor was enucleated by choice. Thirty-five of 49 patients with an imperative indication are without sign of tumor progression after a mean follow-up of 4.5 years. In two patients there was a recurrence after 4 and 5 years, respectively, requiring a second organ-preserving operation. In one further patient there is a suspicion of multiple small tumor lesions 2 years after the first operation. Known metastases were present in 3 of 6 patients who died of their tumors. Sixty-eight of 74 patients operated on electively are without signs of tumor progression after a mean follow-up period of 3.3 years. One patient died from tumor metastases. Two patients had tumor recurrence, requiring nephrectomy and enucleation, respectively.

Adult↗
PubMed1991

[The Mainz pouch. Ileocecal reservoir, Mainz pouch].

The surgical technique for creation of the Mainz-pouch uses 12cm of cecum and ascending colon and 2 ileal loops of the same length for construction of an urinary reservoir, which has proven to be applicable for bladder augmentation, bladder substitution as well as for continent urinary diversion. For the creation of a continent nipple in urinary diversion 6cm of ileum in addition are necessary. As a modification we use the non-infected submucosal imbedded appendix as continence mechanism. Since 1986 a total of 247 patients underwent a Mainz-pouch procedure: 54 for bladder augmentation, 27 for bladder substitution and 166 for continent diversion. The appendix as continence mechanism was used in 30. Postoperative mortality rested under 1%, early complications have been observed in 4.4% and late complications in 13.7% (mean follow-up of 35 months). In the bladder augmentation group 52 patients are completely dry, 2 patients have urge and frequency and 5 patients are on intermittent self catheterisation to avoid residual urine. In the bladder substitution group all patients are continent at daytime. At nighttime 3 patients have leakage if they don't empty their bladder all 4 hours. In the urinary diversion group all but 3 are completely dry and are on intermittent catheterization. The main problem of our initial series was prolapse of the continent nipple which has been solved by staple fixation of the nipple to the bowel wall and to the ileocecal valve or by using the submucosal imbedded appendix.

Adult↗
PubMed1990

Laser assisted urethral closure in the rat: comparison of CO2 and Neodymium-YAG laser techniques.

In 65 male rats a comparative study was undertaken to investigate a Neodymium-YAG and CO2 laser system for the microsurgical repair of longitudinal incisions of the rat urethra. Postoperative investigations included patency tests, necropsy and light microscopy. Use of the laser systems did not reduce operation time. The highest rate of postoperative strictures (90%), urethral fistulas (30%), urinomas (20%) and postoperative deaths (70%) was seen in the Neodymium-YAG laser group. CO2 laser repair was almost as efficacious as microsuture repair, except for a higher rate of urethral fistulas resulting from the initially weak laser weld. Based on these findings, the Neodymium-YAG laser seems unsuitable for urethral repair. Further studies in larger animals are warranted using a CO2 laser in combination with postoperative cystostomy for urinary diversion in order to avoid fistulas in the early postoperative period.

Animals↗
PubMed1990

Urethral tumor recurrences after radical cystoprostatectomy: the case for primary cystoprostatourethrectomy?

Of 273 male patients who underwent radical cystoprostatectomy between 1967 and 1987, 22 were regarded as at risk for urethral recurrence. These patients underwent simultaneous primary urethrectomy or urethrectomy shortly after cystectomy because of the histology of the cystectomy specimen. Of the remaining 251 patients a urethral recurrence was observed in 23 (9.2%). A patient with a urethral recurrence originally had undergone an operation at another hospital. The first urethral tumor recurrence was observed in 1977 but between October 1987 and May 1988, 7 patients were treated for an initial or secondary urethral recurrence. This finding suggests that the rate of urethral recurrence increases with improved survival rates after cystoprostatectomy and longer followup of these patients. Of the 24 patients who had urethral recurrence 21 showed multifocal tumor growth in the primary cystectomy specimen and 2 had unifocal tumors. The original histological status in the patient treated elsewhere is not known. The data suggest that primary simultaneous urethrectomy should be performed in all patients undergoing cystoprostatectomy for multifocal bladder tumors. Patients who retain the urethra require regular and life-long washout cytology studies of the urethra for early diagnosis of recurrent urethral tumor.

Cystectomy↗