Rudolf Knapp

New Onset Hypertension After Extracorporeal Shock Wave Lithotripsy: Age Related Incidence and Prediction by Intrarenal Resistive Index

PURPOSE In a recent study we found an increased resistive index immediately after extracorporeal shock wave lithotripsy (ESWL) in patients older than 60 years, which suggests renovascular disturbance. The present 26-month followup study was undertaken to investigate the relevance of elevated resistive index levels and the incidence of new onset hypertension. MATERIALS AND METHODS Of the initial 76 patients 57, including 20 of the 23 at risk patients 60 or greater years, group 3), were followed for more than 26 +/- 6 months after ESWL. Followup included 2 resistive index measurements by Doppler ultrasound of the treated and the contralateral kidney, at least 2 blood pressure measurements 1 week apart and excretory urography as well as determination of plasma renin activity in 9 patients. RESULTS With 1 exception, elevated resistive index levels and hypertension were observed exclusively in patients older than 60 years. In these patients the resistive index ranged between 0.65 and 0.86 (mean plus or minus standard deviation 0.74 +/- 0.05, normal less than 0.7). This increase in resistive index was statistically significant (p < 0.0001). Compared to the levels obtained immediately after ESWL, the resistive index continued to increase in all 9 patients older than 60 years who had hypertension (45%), whereas in the normotensive patients the resistive index was either stable or decreased. There was a strong positive correlation (0.903) between pathological resistive index levels and blood pressure. CONCLUSIONS Patients older than 60 years are at risk for disturbances of renal perfusion as assessed by the resistive index, and 45% of these patients have new onset hypertension within 26 months of treatment.

CT-guided stereolithography as a new tool in craniofacial surgery

CT-guided stereolithography provides an acrylic model which exactly replicates the original structure. It allows optimal preoperative planning and intraoperative management. This application proved advantageous in surgical correction of a wide midline craniofacial cleft in a baby.

Variability of Doppler parameters in the healthy kidney: an anatomic-physiologic correlation.

Contradictory results have been obtained in classifying various renal diseases when trying to use the resistive index measured by duplex Doppler technique in renoparenchymal arteries. These measurements may have been influenced by the lack of standardization of the anatomic site at which the renoparenchymal artery is sampled. To elucidate this influence, we measured the resistive index, peak systolic velocity, end diastolic velocity, and pulsatility index in 120 healthy kidneys at three different positions of the renal vasculature. The resistive index at the level of the interlobar‐arcuate arteries proved to be the parameter with the most consistent results and should be preferred in clinical applications.

Intraurethral ultrasound: diagnostic evaluation of the striated urethral sphincter in incontinent females

Abstract. The aim of our study was to evaluate the striated urethral sphincter (rhabdosphincter) in incontinent females by means of intraurethral ultrasound (IUUS). Thirty-four incontinent and 11 continent female patients were examined by means of 12.5-MHz endoluminal ultrasound (US). The distance between the inner contour of the sphincter muscle and the US catheter was measured in the contracted and the non-contracted condition. The US findings were correlated with those obtained by urodynamic studies. Partial or complete loss of sphincter function was detected in patients with stress urinary incontinence (SUI). Reduced sphincter function was not observed in patients with urge incontinence and continent volunteers. The findings on US were found to correlate well with the grade of SUI. The IUUS technique offers the benefit of direct visualization of the sphincter mechanism. Therefore, endoluminal US may become an important adjunct in the diagnostic evaluation of SUI and will possibly provide new insights for a better therapeutic strategy.

Age-Related Changes in Resistive Index Following Extracorporeal Shock Wave Lithotripsy

PURPOSE Changes in intrarenal vascular resistance after extracorporeal shock wave lithotripsy (ESWL*) were studied with Doppler ultrasound techniques. MATERIALS AND METHODS In 76 patients the resistive index was measured at an interlobar artery before and after ESWL in the treated and contralateral kidneys. The resistive index levels were compared to N-acetyl-beta-D-glucosaminidase levels in 40 patients. RESULTS We found an age-related positive linear correlation between post-therapeutic resistive index increases and patient age. N-acetyl-beta-D-glucosaminidase levels were also elevated after ESWL but these elevations were not age-related. CONCLUSIONS Elderly patients have a higher risk of post-ESWL renal tissue damage.

Restoration of voluntary emptying of the bladder by transplantation of innervated free skeletal muscle.

BACKGROUND On the basis of studies with animals and experience with functioning muscle transfer in plastic surgery, we have developed a surgical technique to restore detrusor function for patients with bladder acontractility in whom there is no treatment alternative. METHODS Three patients (aged 26 years, 28 years, and 68 years) with bladder acontractility as a result of spinal-cord injury (two patients) and chronic overdistension (one patient), who required catheterisation for bladder emptying for 5 years, 2 years, and 2 years, respectively, took part in our study. The patients were treated with microneurovascular free transfer of autologous latissimus dorsi muscle to the bladder to restore detrusor function. Follow-up included clinical and urodynamic evaluation, colour doppler sonography, intravenous urography, and flow-mode computerised tomography. FINDINGS The three patients voluntarily emptied their bladders at 16 weeks, 16 weeks, and 30 weeks after surgery, respectively. There was no need for further catheterisation throughout the follow-up period. On urodynamic assessment at 12 months after the operation bladder capacity was found to be 600 mL, 600 mL, and 650 mL, residual urinary volume 0 mL, 50 mL, 90 mL, and maximum flow rate 26 mL/s, 25 mL/s, and 18 mL/s, respectively. Activity at the transplanted latissimus dorsi was confirmed by ultrasonography and flow-mode computerised tomography. INTERPRETATION Microneurovascular free transfer of latissimus dorsi muscle to functionally restore a deficient detrusor muscle has proved to be successful for the three patients in our study. This technique may also be an option to restore the function of other smooth-muscle organs.

Blood pressure changes after extracorporeal shock wave nephrolithotripsy: prediction by intrarenal resistive index

In order to identify a high-risk group for the development of arterial hypertension after extracorporeal shock wave nephrolithotripsy (ESWL), we correlated the increase in renovascular resistance induced by ESWL in 79 normotensive patients with changes in arterial blood pressure occurring 20 (+-3) months after therapy. Renal vascular resistance was measured as resistive index (RI) by duplex Doppler sonography in both kidneys. Mean RI before treatment was 0.620±0.035 (SD). After treatment, we observed a significant and age-dependent increase in the RI in the treated kidney to 0.673 ± 0.06. Of the patients with a post-ESWL RI> 0.690, 39% developed hypertension. Posttherapy RI values surpassing 0.690 showed a 0.8 sensitivity and a 0.7 specificity in predicting arterial hypertension. Intrarenal Doppler ultrasound (US) is useful to find the high-risk group for arterial hypertension after ESWL.

Three-dimensional computed tomography of the reconstructed lower urinary tract: technique and findings.

Abstract. The aim of this pilot study in 54 patients was to improve the visualization of the anatomy and postoperative changes in the pelvic topography after bilateral ureteroileal urethrostomy, using surface rendering of electron beam CT (EBCT) data for the 3D display. Fifty-four patients (39 men and 15 women) were scanned with an EBCT unit between 3 and 110 months after performing orthotopic ureteroileal urethrostomy (“Hemi-Kock”) or ureteroileal rectosigmoidostomy. Various parameters and spatial viewing points were used in the 3D reconstruction, which was performed interactively on external workstations with commercially available software. The anti-reflux nipple was visualized as a distinct structure in all patients. In 8 patients with an interval of more than 12 months between surgery and CT, the pouch had developed an ovoid shape almost indistinguishable from the original bladder. The segmented data sets were partly animated to display the anatomy as virtual endoscopy. Three-dimensional depiction and virtual endoscopy of the neobladder using EBCT are a new way of imaging the postoperative anatomy. Its clinical efficacy in the diagnosis of inconclusive postoperative morbidity, especially voiding problems, and planning of necessary therapy have to be the subject of further evaluation.

The value of the World Wide Web for tele-education in radiology

We assessed Websites for radiological education. Of several hundred sites identified, 30 were randomly selected for evaluation by two groups of observers. All Web pages were rated with respect to time required to access the information; structure and organization of the site; image quality; and information content and relevancy. Rapid access was gained to many educational radiology Websites, which contained large numbers of interesting radiological images of good quality. A weak point was the structure and organization of the sites. The greatest variability in ratings was found in the information content and relevancy of the Websites.

Anatomy of the eustachian tube as demonstrated by endoluminal ultrasonography.

Using a new application of the endoluminal approach, we were able to demonstrate the sonographic anatomy of the eustachian tube in vitro and in vivo and correlate it with the plastic‐embedded specimen. Five adult normocephalic cadavers, two patients, and one specimen especially prepared for embedding in plastic were examined. A specifically developed device was used to insert the ultrasound transducer employing an endo‐oral approach. The investigation was performed using an intravascular ultrasound unit. In all cases the tube could be visualized in its entirety and relevant anatomic structures identified and compared with the specimen at the corresponding levels. The deeper layers, including the paratubal structures and the mucosa, could be distinguished for the first time by means of endoluminal ultrasonography. Now that endoluminal ultrasonography has revealed this anatomic information, further studies will be able to gauge the clinical efficacy of our method in cases of ventilatory, drainage, and clearance problems. The images showed no difference between the structures in vitro and in vivo, and the vivo examination was even easier than the in vitro one owing to better tissue turgor.