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P Alken

Publications and source records attributed to P Alken.

At least 145 records · Page 8Linked to original sources
PubMed1994

Retroperitoneal laparoscopic nephrectomy and other procedures in the upper retroperitoneum using a balloon dissection technique.

This article describes a hydraulic balloon dissection technique. The retroperitoneum is developed via a small lumbodorsal incision between the edges of the musculus latissimus dorsi and musculus obliquus externus and then after visualization of its correct position the balloon catheter is filled with 500-1,200 ml of warm normal saline (according to patient size). The device consists of the finger of a surgeon's glove ligated around the end of a rigid bladder catheter. The balloon insufflation is maintained for 5 min to guarantee adequate hemostasis. Recently, we have replaced the balloon catheter by a balloon trocar sheath allowing direct endoscopic control of the hydraulic dissection. After retrieval of the balloon the CO2 insufflator is connected to the first trocar. All secondary trocars are placed under endoscopic control. The hydraulic dissection techniques also enable optimal creation of an effective pneumoperitoneum in children. Until now, we have used this technique for twelve procedures in the upper retroperitoneum including five nephrectomies, two nephroureterectomies, one tumor nephrectomy, one nephropexy, one renal cyst marsupialization and two renal biopsies. Up to now we have encountered no major complications. Three of the nephrectomized patients had undergone multiple previous abdominal surgical interventions. The retroperitoneal approach allows the surgeon to apply similar dissecting techniques as used in respective open procedures. It has become the routine approach for laparoscopic procedures in benign renal disease. This procedure can be performed even in cases with previous abdominal surgery.

Adult↗
PubMed1994

[Ureteral stent reinforced with a spiral--an alternative to internal drainage of urine].

Internal urinary diversion of chronic ureteral obstruction is not sufficient in up to 60% of the cases. Factors for this high failure rate are tumor compression, catheter kinking or a small stent lumen. To prevent such problems we have developed a new ureteral stent which is stable in form in spite of a large stent lumen. This catheter is made of a thin polyurethane tube which is supported by a built-in metallic spiral wire. We have used this stent in 16 cases of chronic ureteral obstruction. Stent placement was successful in 14 cases. Other than urinary tract infection in two cases, bladder urgency in one case and stent dislocation in another case there were no complications. Hydronephrosis disappeared soon after stent application in 12 out of 14 cases. In the remaining two cases hydronephrosis was decreased, but not totally eliminated. Catheters were left in place for an average of 6.5 weeks (2.5-8.5). A change of catheter due to catheter blockage was necessary only in one case. In conclusion, this spiral reinforced stent enables a better internal urinary drainage especially in cases of malignant ureteral obstruction.

Female↗
PubMed1994

Ureteral stone. Treatment using the Modulith SL 20 and Lithostar plus.

The treatment of ureteric calculi by extra-corporeal shock waves was found to have an 80% success rate by Mannheim authors, regardless of the site of the calculus. The authors compared two 3rd generation apparatuses: 1--the Siemens Lithostar Plus, in which waves are produced by a electromagnetic cylinder and focussed by a parabolic electromagnetic cylinder and focussed by a parabolic reflector: 2--the Storz Medical Modulith SL 10, in which waves produced by an electromagnetic coil are focussed by acoustic lenses. Both apparatuses are based upon image-intensification and ultrasonography concepts. No difference in efficacy was found between the two apparatuses. A second shock wave session was necessary in 16% of cases and some other type of additional treatment in 7% of cases.

Acoustics↗
PubMed1994

Hydrodynamic assessment of efferent limb valve mechanisms in continent urinary diversion: comparative study on a cadaveric model.

Various valve mechanisms, customarily employed in continent urinary diversion, were constructed from fresh cadaveric porcine bowel for later urodynamic assessment. A total of six different types of valves were formed from ileum or colon in varying lengths and tested by volume pressure trials. The leak point or maximum pressure were recorded at constant perfusion rates of 30 ml/min of the constructed reservoir. Ileal or colonic nipple valves, as well as the embedded or pulled-through ileum, tapered to 12 F at a length of 3 cm, withstood maximum pressures ranging between 75 and 138 cm H2O before leakage or protrusion of the valve occurred. Plicated or tapered terminal ileum in caecal reservoir revealed water leakage at pressures as low as 25 to 40 cm H2O. A newly-developed valve mechanism consisting of a 12 F, plicated colonic-serosal tunnel with a minimum intra-reservoir length of 5 cm resisted maximum pressures of more than 70 cm H2O. Our cadaveric porcine bowel model proved to be reliable for acute volume/pressure trials and correlated with all clinical urodynamic results and animal trials. It is simple, inexpensive and allows scope for individual ideas before commencing with animal trials.

Anastomosis, Surgical↗
PubMed1994

[Incidence and differential diagnosis of hyperechoic kidney tumors].

The frequency of kidney tumours was determined in a prospective study of 11,076 consecutive patients investigated sonographically in a department of internal medicine. A further objective of the study was to establish whether the echo characteristics of the renal tumours alone allow sonographic categorization into benign and malignant tumours, how often it is possible to diagnose angiomyolipomas of the kidneys on the basis of sonography alone, and how frequently further imaging techniques and/or invasive methods are necessary. In this patient series, 68 solid renal lesions were detected (0.6%): 15 of the lesions were hypernephroid carcinomas (0.13%) and 28 angiomyolipomas (0.25%). All angiomyolipomas were hyperechoic. In contrast, only 3 of the hyperechoic tumours were hypernephroid carcinomas. Owing to the unequivocal sonographic appearance, 16 out of 28 angiomyolipomas could be diagnosed on the basis of sonography alone. Additional diagnostic measures were necessary for only 12 of these tumours (CT, angiography, intravenous pyelogram, and an operation in 1 patient, who had an angiomyolipoma infiltrating into the vena cava). In contrast to this, computer tomography was necessary in addition for the diagnosis of all malignant tumours, and angiography in 4 cases.

Adult↗
PubMed1993

The recurrence rate of stones following ESWL.

With extracorporeal shockwave lithotripsy (ESWL) stone fragmentation and the potential creation of residual stones has become an integral part of the treatment strategy. Therefore true recurrence, regrowth and pseudo-recurrence determine the rate of new stone formation. In unselected series the overall recurrence rate after ESWL varies between 6% after 1 year and 20% after 4 years. The comparison between the recurrence rate after ESWL and the natural recurrence rate reveals that the results of ESWL are better than expected. Lithotripsy has no special effect on true stone recurrence, and even pseudo-recurrence is of minor clinical significance.

Follow-Up Studies↗
PubMed1993

Experimental basis of shockwave-induced renal trauma in the model of the canine kidney.

Using the new electromagnetic shockwave source of the Modulith SL 20 shockwave-induced renal trauma was evaluated by acute and chronic studies in the the canine kidney model. In a further study the electromagnetic shockwave source of the Lithostar Plus Overhead module was tested. Overall, 92 kidneys were exposed to shock waves coupled either by water bath (Modulith lab type) or by water cushion (Modulith prototype, Lithostar Overhead) under ultrasound localization. The generator voltage ranged between 11 and 21 kV, the number of impulses between 25 and 2500. After application of 1500/2500 shocks the extent of the renal lesion depended strictly on the applied generator voltage and was classified into 4 grades: Grade 0, no macroscopic trauma detectable (at 11-12 kV); grade 1, petechial medullary bleeding (at 13 kV); grade 2, cortical hematoma (at 14-16 kV); and grade 3, perirenal hematoma (17-20 kV). Whereas at low and medium energy levels the number of shocks played only a minor role, at maximal generator voltage (20 kV) even 25 impulses induced a grade 2 and 600 shocks a grade 3 lesion, emphasizing the importance of shockwave limitation in the upper energy range. In shockwave-induced renal trauma a vascular lesion was predominant and cellular necrosis was secondary. Coupling with a water cushion resulted in a 15%-20% decrease in the disintegrative and traumatic effect, which was compensated for by increasing the generator voltage by 2 kV. Long-term studies showed complete restitution following grade 1 and 2 trauma, whereas after a grade 3 lesion a small segmental and capsular fibrosis without hyperplasia of the juxtaglomerular apparatus was observed. Based on the characteristic ultrasound pattern found in the first study, the threshold for induction of grade 1 lesion was investigated. With both lithotripters a wide range for induction of a grade 1 lesion (Modulith 234-411, Lithostar Plus 220-740) and also a significant overlapping with grade 0 and 2 lesions was seen at low energy settings (levels 2-4). In contrast, the range of shocks (Modulith 96-150, Lithostar Plus 90-142) and overlapping was minimal when high energy was used (levels 7-9). Finally, the disintegration-trauma coefficient combining the results obtained in a standard stone model with those of the canine kidney model was introduced.

Animals↗
PubMed1993

[Are there metastatic angiomyolipomas?].

An angiomyolipoma is now mostly diagnosed by sonography due to sonographically typical criteria, such as abundant echoes and clear delineation, or via CT, since it is a process rich in fat and hence hypodense. Laying bare by surgery will only be required in case of an atypical localisation or expansive tumour growth. Two case reports are presented with ipsilateral lymph node infiltration in multifocal angiomyolipoma and expansion of the tumour into the vena cava via the renal vein.

Adult↗
PubMed1993

Transperitoneal laparoscopic nephrectomy: training, technique, and results.

Transperitoneal laparoscopic nephrectomy was integrated into our daily routine within a 6-month period by means of a step-by-step training program progressing from a pelvic trainer to animal studies (N = 15) to laptent-assisted surgery. The pneumoperitoneum is created with the patient in the flank position, enabling insertion of three trocars: 10-mm periumbilical (Port I), 5/12-mm subcostal (Port II), and 12/5-mm above the iliac spine (Port III). After medial mobilization of the colon, two additional 5-mm trocars (Ports IV and V) are inserted into the lateral abdominal wall parallel to Ports II and III. Once clipping and dissection of the ovarian (spermatic) vein has been carried out, the ureter is identified and dissected. Retraction of the proximal ureter exposes the renal hilum, allowing dissection of the renal vessels. The renal vein is dissected using an endoscopic stapling device, while accessory veins and the renal artery are clipped. Organ retrieval is achieved with a specially designed tissue pouch (Lapsac) and digital fragmentation of the kidney within the organ bag. Using this technique, we have treated 24 patients with benign (N = 20) and malignant (N = 4, including adrenalectomy) renal disease. The mean operative time was 239 (115-300) minutes. In four cases, open surgery was required because of bleeding (N = 2), severe perinephric inflammation (N = 1), or bowel injury (N = 1). For relief of wound pain, an average of 1.15 vials of analgesic (morphine derivatives)/patient were administered for 2.4 days. The postoperative hospital stay averaged 6.2 (4-10) days.

Animals↗
PubMed1993

Correction of distal hypospadias: ventral adaption of the prepuce and meatal advancement.

In distal hypospadias without chordee, surgical correction has a purely cosmetic character. In contrast to standard techniques focusing on meatal position, parents often regard the redundant dorsal prepuce and its missing ventral fusion as the essential constituent of this malformation. The operative technique, presented in detail, emphasizes on foreskin reconstruction. The ventral adaption of the prepuce (VAP procedure) results in a penis with normal appearance. Complications presented reveal the importance of proper patient selection.

Child↗
PubMed1993

Comparison of urodynamic findings and response to oxybutynin in nocturnal enuresis.

Sixty-three children with persistent nocturnal enuresis were urodynamically assessed and subsequently treated with oxybutynin chloride. Urodynamic evaluation, including graduation of detrusor instability and comparison of maximum bladder capacity with the age-predicted norm, confirmed an inadequate storage function in 84% of the children. Treatment benefit totaling 70% was dependent upon urodynamic findings, with best relation to the determined bladder capacity. The value attributed to graduation of uninhibited contractions was prognostic in accordance with further subdivision of the maximum bladder capacity. Treatment benefit was limited in children with normal urodynamic findings.

Adolescent↗
PubMed1993

The technique of transperitoneal laparoscopic nephrectomy, adrenalectomy and nephroureterectomy.

In the traditional kidney position three trocars are inserted after creation of a pneumoperitoneum: 10 mm periumbilical (port I), 10/12 mm subcostal (port II) and 12/10 mm above the iliac spine (port III) in the mamillary line. After laterocolic incision the colon is dissected away from the lateral wall. Thereafter two 5-mm trocars (ports IV, V) are inserted into the lateral abdominal wall parallel to parts II and III. Following clipping and dissection of the ovarian (spermatic) vein, the ureter is isolated and incised. Then the cranial part of the ureter is used as a retractor exposing the renal hilum for dissection of the renal vessels. The main renal artery and vein are dissected separately by use of an endoscopic stapling device (Endo-GIA, white magazine). Finally, the kidney including Gerota's fascia is isolated from the adrenal and the upper peritoneum. Entrapment of the organ is performed with a specially designed bag (Lap-sac). The neck of the bag is brought out onto the surface of the abdomen (via port II/III) allowing digital morcellation with index finger inside the bag and removal of the organ in several pieces. We have applied this technique for 17 procedures in the upper retroperitoneum: 9 transperitoneal laparoscopic nephrectomies (TLN) for benign disease (5 hydronephrosis, 3 renovascular disease, 1 chronic pyelonephritis), 3 radical TLN including adrenalectomy for renal cell carcinoma (T2G2), 1 adrenalectomy for a cortical adrenaloma, 1 nephroureterectomy, 1 diagnostic ureterolysis and 2 modified retroperitoneal lymphadenectomies for stage I testicular cancer. The mean operation time was 4 h (2-5), the mean postoperative hospital stay 6 days (4-12).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1993

The effect of single shock waves on the vascular system of artificially perfused rabbit kidneys.

Extracorporeally-perfused rabbit kidneys were exposed to five shock waves at 14 kV on the XL1 Dornier experimental lithotripter (Dornier Medical Systems, Inc., Germering, Germany). While the perfusion flow rate was kept constant, the arterial perfusion pressure was recorded to assess changes in vascular resistance. Immediately after shock wave application, perfusion pressure decreased by 20%-30%, followed by a short, relative pressure rise that did not reach pretreatment values. Fifteen-twenty minutes later, arterial perfusion pressure reattained pretreatment values. Subsequent to treatment, urine flow decreased by greater than 50%. The observed pressure rise was also induced in nontreated kidneys by perfusion with the effluent of treated kidneys indicating that this is based on a humoral mechanism. On the other hand, shock wave application to formalin fixed kidneys only caused a marked decrease in arterial perfusion pressure, suggesting that this effect is due to a pure mechanical interaction of the shock wave also found with denaturated kidneys. The observed decrease of urine flow is probably caused by a decreased filtration rate. Since this was not the case in nontreated kidneys being perfused with the effluent of treated kidneys, the reduction of urine flow after extracorporeal shock wave lithotripsy does not appear to be mediated by a humoral factor, but is more likely a result of the mechanically-induced vasodilation with consecutive decline of the glomerular filtration rate.

Animals↗
PubMed1993

[Antegrade-retrograde urethrotomy in therapy of high degree urethral stricture].

In the case of urethral stricture which is non-passable by conventional "cold knife" urethrotomy, open urethroplasty can be avoided by combined antegrade-retrograde urethrotomy (ARUT). A rigid cystoscope is guided, through a dilated, suprapubic cystostomy channel, to the stricture in the membranous or bulbular urethra. A urethrotome is inserted in the retrograde direction and the "cut to the light" procedure is adopted. Using the ARUT method, successful realignment was achieved in 9 patients; 4 strictures were trauma- or urethritis-induced and 5 were the result of transurethral management. Recurrent stricture in 4 out of 7 cases (57%) required further urethrotomy. There was no recurrence in 4 out of 7 patients for at least 5 months subsequent to the last treatment. All patients were spared open surgery. The antegrade-retrograde technique exists since 1978. Up to date, 63 cases have been mentioned in the literature. The primary therapy success rate is 25%. Successful retreatment following recurrence was observed in 65%. We recommend ARUT as first-choice treatment for severe strictures of the bulbular and membranous urethra.

Adult↗
PubMed1993

[Laparoscopic training in urology. An essential principle of laparoscopic interventions in the retroperitoneum].

The main problem with clinical introduction of laparoscopic techniques in urology is that despite experience with endoscopy no significant endoscopic training is given. Laparoscopic nephrectomy, in particular, is a rather complicated procedure and needs an adequate training concept: The beginner should have the possibility of practising in vitro in a closed "pelvi-trainer" to learn video-optical coordination and orientation; then it is necessary to get used to handling the instruments and practise the different steps of the procedure (i.e. clipping of vessels, sacking of the kidney) either in phantom models or in explanted animal organs. On this basis, we performed laparoscopic nephrectomy in an animal model (n = 18 porcine kidneys). We were able to standardize the technique of creating a pneumoperitoneum, the positioning of the animal, the site and size of the trocars, and preparation and clipping techniques (i.e. Endo-GIA) and entrapment of the kidney (testing different organ bags). A step-by-step approach was used for the introduction to clinical application. For simulation and training of video-assisted preparation techniques in patients and step-wise introduction to laparoscopy (instruments, endocoagulation, trocars), we created a "lap-tent", which was placed over the wound after exposition of Gerota's fascia. Further preparation was performed under laparoscopic conditions (without pneumoperitoneum) with a limited time allowed (1 h). Thereafter, we started with time-limited laparoscopy and laparoscopic lymphadenectomy prior to pelvic surgery (prostatectomy, cystectomy) to introduce the staff to the technique of pneumoperitoneum and placement of the trocars and to the use of the instruments in general. Based on this step-by-step training concept, after a 6-months period we were successful in introducing transperitoneal laparoscopic nephrectomy (TLN) to our clinical routine. So far, we have performed 20 laparoscopic nephrectomies, 1 nephro-ureterectomy, 4 tumour nephrectomies (inducing adrenalectomy), 2 adrenalectomies, and 6 modified retroperitoneal lymphadenectomies. In the lesser pelvis we have experience with 20 laparoscopic varicocelectomies, 23 pelvic lymphadenectomies, and 5 diagnostic laparoscopies for cryptorchidism (February 1993).

Adrenalectomy↗