Pelvic floor electrophysiology in spinal cord injury.

OBJECTIVE: The study aimed to investigate sacral peripheral nerve function and continuity of pudendal nerve in patients with chronic spinal cord injury (SCI) using pelvic floor electrophysiological tests. METHODS: Twelve patients with low cervical or thoracic SCI were prospectively included. Quantitative external anal sphincter (EAS) muscle electromyography (EMG), pudendal nerve terminal motor latency (PNTML) testing, bulbocavernosus reflex (BCR) testing and pudendal short-latency somatosensory-evoked potential (SEP) measurement were performed. RESULTS: In EAS muscle EMG, two patients had abnormal increased spontaneous activity and seven prolonged motor unit potential duration. PNTML was normal in 10 patients. BCR was present with normal latency in 11 patients and with prolonged latency in one. The second component of BCR could be recorded in four patients. SEPs showed absent cortical responses in 11 patients and normal latency in one. CONCLUSIONS: Pudendal nerve and sacral lower motor neuron involvement are significantly associated with chronic SCI, most prominently in EAS muscle EMG. The frequent finding of normal PNTML latencies supports earlier concerns on the utility of this test; however, BCR and pudendal SEPs may have clinical relevance. SIGNIFICANCE: As intact peripheral nerves including pudendal nerve are essential for efficient supportive therapies, pelvic floor electrophysiological testing prior to these interventions is highly recommended.

International Children's Continence Society's recommendations for therapeutic intervention in congenital neuropathic bladder and bowel dysfunction in children.

PURPOSE: We present a consensus view of members of the International Children's Continence Society on the therapeutic intervention in congenital neuropatic bladder and bowel dysfunction in children. MATERIAL AND METHODS: Discussions were held by a group of pediatric urologists and gastroenterologists appointed by the board. The following draft review document was open to all the ICCS members via the ICCS web site. Feedback was considered by the core authors and by agreement, amendments were made as necessary. The final document is not a systematic literature review. It includes relevant research when available as well as expert opinion on the current understanding of therapeutic intervention in congenital neuropatic bladder and bowel dysfunction in children. RESULTS: Guidelines on pharmalogical and surgical intervention are presented. First the multiple modalities for intervention that do not involve surgical reconstruction are summarized concerning pharmacological agents, medical devices, and neuromodulation. The non-surgical intervention is promoted before undertaking major surgery. Indicators for non-surgical treatments depend on issues related to intravesical pressure, upper urinary tract status, prevalence of urinary tract infections, and the degree of incontinence. The optimal age for treatment of incontinence is also addressed. This is followed by a survey of specific treatments such as anticholinergics, botulinum-A toxin, antibiotics, and catheters. Neuromodulation of the bladder via intravesical electrical stimulation, sacral nerve stimulation, transcutaneous stimulation, and biofeedback is scrutinized. Then follows surgical intervention, which should be tailored to each individual, based on careful consideration of urodynamic findings, medical history, age, and presence of other disability. Treatments mentioned are: urethral dilation, vesicostomy, bladder, augmentation, fascial sling, artificial urinary sphincters, and bladder neck reconstruction and are summarized with regards to success rates and complications. Finally, the treatment on neuropathic bowel dysfunction with rectal suppositories irrigation and transrectal stimulation are scrutinized.

The effect of alarm treatment on the functional bladder capacity in children with monosymptomatic nocturnal enuresis.

PURPOSE: We studied the characteristics of a group of monosymptomatic nocturnal enuretics successfully treated with the alarm system, with special reference to changes in functional bladder capacity. MATERIALS AND METHODS: The diaries of 7 girls and 19 boys 7 to 13 years old with severe nocturnal enuresis, small daytime bladder capacity (70% or less of expected capacity for age) and poor or absent response to desmopressin were analyzed. Patients were treated with an alarm until complete dryness was achieved for 21 consecutive nights before ending therapy. Immediately after the treatment they recorded a 1-week followup diary of voiding and fluid intake. RESULTS: Mean duration of the alarm treatment was 82 days, and there was no change in nocturnal or 24-hour diuresis from baseline to followup. Nocturia developed during the alarm treatment in 48% of the children. The nocturnal diuresis on nocturia nights was significantly higher than on nights without nocturia. Daytime functional bladder capacity increased significantly in children with and without nocturia. CONCLUSIONS: Treatment with an alarm system increases daytime functional bladder capacity significantly in children with and without nocturia. A higher nocturnal urine production on nocturia nights explains why some children have nocturia and others do not.

Norepinephrine inhibits the pelvic pressure increase in response to flow perfusion.

PURPOSE: We evaluated the effects of norepinephrine on transport pressures in the normal upper urinary tract of the pig during increasing perfusion rates. MATERIALS AND METHODS: Anesthetized Danish landrace Yorkshire pigs weighing 38 to 40 kg were studied. Transparenchymally 2, 6Fr catheters were introduced into the left renal pelvis for pressure measurements and perfusion, respectively. An ultrasonic flow probe was inserted around the left renal artery to record blood flow. A 10Fr catheter was placed transurethrally for bladder drainage and the bladder was maintained empty during the entire study. In the 5 group 1 pigs the pelvic pressure increase was examined at increasing perfusion rates of the renal pelvis (2, 4, 6, 8, 10 and 15 ml per minute) in response to endoluminal administration of increasing concentrations of norepinephrine (0, 5, 50 and 100 microg/ml) in saline. In the 5 group 2 pigs the pressure flow study was also done 4 times per animal using isotonic saline. RESULTS: Endoluminal norepinephrine had a dose dependent effect on the pressure flow relationship. Perfusion with 5 and 50 microg/ml norepinephrine caused a delayed increase and a decrease in pelvic pressure in response to increasing flow rates, whereas perfusion with 100 microg/ml norepinephrine significantly inhibited and almost eliminated the pressure increase at all perfusion rates compared with saline perfusion. Importantly there were no changes in blood pressure, the heart rate or renal arterial blood flow. In group 2 perfusion with isotonic saline resulted in the same pressure response to increasing flow rates each time. CONCLUSIONS: Endoluminal administration of norepinephrine caused a dose dependent inhibition on the pressure phases of the pressure flow relationship of the upper urinary tract in pigs. No systemic changes were observed. These observations may provide a useful adjuvant treatment strategy for upper urinary tract stone treatment and endoscopy.

The relationship between desmopressin treatment and voiding pattern in children.

OBJECTIVE: To collect data on voiding patterns at baseline (no treatment) and during short-term desmopressin treatment, with special reference to the functional and the mean bladder capacity. PATIENTS AND METHODS: The study included 120 children (aged 6-16 years) with monosymptomatic nocturnal enuresis. While at home they recorded their fluid intake and diuresis in two separate periods, i.e. 2 weeks as a baseline registration and another 2 weeks during desmopressin titration. On four study days the children recorded the time and volume of all voids and of fluid intake. From the diaries their functional and mean bladder capacities, 24-h diuresis and day/night ratio of diuresis were determined. RESULTS: The mean 24-h diuresis was significantly lower during short-term desmopressin treatment. In most of the enuretics the mean day/night ratio increased on desmopressin treatment. The mean functional and mean bladder capacities were unaffected by desmopressin. Those not responding had bladder capacities of approximately 100 mL less than full responders. Regardless of response, practically all the enuretics in the study had a smaller functional bladder capacity than expected for their age. Among responders the morning void was significantly larger than the following voids during the day, and among non-responders the fourth void was significantly larger than the previous voids in the day. Desmopressin treatment did not influence these volumes significantly. CONCLUSIONS: Short-term desmopressin treatment does not affect functional and mean bladder capacity; 24-h urine production was reduced significantly (P<0.01) during desmopressin treatment.

Resistive index: an experimental study of the effects of diuretic stimulation in the unobstructed porcine kidney.

OBJECTIVE: To study the effects of diuretic stimulation with frusemide and mannitol on the renal resistive index (RI) of the undilated unobstructed porcine kidney. MATERIALS AND METHODS: Experiments were carried out on 14 pigs divided into two equal groups (A and B), under general anaesthesia. In all pigs both ureters were catheterized, thereby allowing urine output to be measured on each side separately, and an indwelling catheter in a femoral artery used to continuously measure the systemic blood pressure. Furthermore, in five pigs from each group, right renal blood flow was measured by ultrasonic flow probes placed around the renal arteries. The right kidney RI was measured at baseline and at 5-min intervals after frusemide (group A) and mannitol (group B) stimulation, for 75 min. RESULTS: Frusemide caused significant increases in diuresis (P < 0.001) and renal blood flow (P = 0.009). This was accompanied by a significant decrease in mean arterial pressure (P < 0.001). The RI was unaffected (P = 0.706), with mean values in group A of 0.58-0.65. Mannitol also caused a significant increase in diuresis (P < 0.001) and a subtle but significant decrease in mean arterial pressure (P < 0.001). However, renal blood flow was unaffected by the diuretic (P = 0.820); the mean RI values were unaffected, at 0.61-0.66 (P = 0.375). CONCLUSIONS: These results show that diuretic stimulation with frusemide or mannitol does not affect the RI of the unobstructed undilated porcine kidney, despite significant changes in diuresis, renal blood flow and mean arterial pressure.

Short- and long-term repeatability of intrarenal resistive index in the pig.

RATIONALE AND OBJECTIVES: To evaluate the short- and long-term repeatability (intraobserver variation) of the renal resistive index (RI) in a pig model. METHODS: Under standardized ambient conditions, short- and long-term repeatabilities were assessed by measuring the RI three consecutive times at 30-minute intervals in 14 pigs and twice 4 weeks apart in 6 pigs, respectively. Repeatability was judged according to predefined criteria, which included calculation of coefficients of variation (CVs) and repeatability coefficients combined with visual assessment and estimation of bias. RESULTS: Short-term repeatability was acceptable, having an average CV of 4.9% +/- 2.9% and of 6.1% +/- 4.7% in two comparisons, findings that were reiterated in the visual assessment. Long-term results were, however, less consistent, having an average CV of 8.1% +/- 6.1% and prominent scatter on the visual assessment graphs. CONCLUSIONS: In this study, RI measurements showed an acceptable short-term repeatability, whereas long-term results were less consistent. The components of error contributing to the modest long-term repeatability need to be investigated in studies of larger populations.

The intrarenal resistive index as a pathophysiological marker of obstructive uropathy.

PURPOSE: The intrarenal resistive index is a physiological parameter that indirectly reflects the degree of resistance in the intrarenal vasculature. Resistive index measurements have been advocated for the diagnostic evaluation of several renal pathologies, including obstructive uropathy. However, despite extensive research in this field during the last decade clear guidelines on the use of resistive index measurements for discriminating obstructive from nonobstructive dilatation of the upper urinary tract remain elusive. Therefore, we reviewed the literature to clarify the proper role of resistive index measurements in the context of obstructive uropathy. MATERIALS AND METHODS: We reviewed the recent literature on the use of resistive index measurements for the diagnostic evaluation of obstructive uropathy. RESULTS: Despite a continuously growing body of literature the resistive index has yet to be recognized as a dependable parameter when it comes to resolving the long-standing dilemma of the dilated upper urinary tract. While proponents have observed that this method has sensitivity and specificity that supersede those of conventional methods, opponents have reported that the resistive index is an unreliable parameter that is prone to systemic and local influences. CONCLUSIONS: Resistive index measurements are still in a developmental phase. Additional studies are needed before this technique may be used reliably for the diagnosis of obstructive uropathy.

Resistive index: an experimental study of the normal range in the pig.

OBJECTIVES: To study the normal range and distribution of the resistive index (RI) and the resistive index ratio (RIR) in the non-obstructed non-dilated porcine kidney, and to assess the reliability of the threshold values RI 0.70 and RIR 1.10 as prognosticators of true obstruction in the upper urinary tracts. METHODS AND MATERIALS: Twenty female pigs of Danish land race breed were studied under general anaesthesia. Blood pressure and urine output was monitored throughout the experiment. Doppler evaluations were obtained from an interlobar artery in the lower half of each kidney, and the RI was calculated as the average of 3 x 3 cycles for each side independently. Statistical analysis of the obtained results was performed. RESULTS: Forty renal units were studied. The RI values ranged from 0.48-0.85 (mean 0.63). Nine renal units (22.5%) had RI values > or = 0.70. RIR values ranged from 1.00-1.38 (mean 1.07). Three RIR values (15%) were above 1.10. There was no statistically significant relationship between RI and laterality (p = 0.25), and no overall significant relationship between RI and mean arterial blood pressure (r2 = 0.21) or urine output (r2 = 0.004). CONCLUSIONS: This study shows a wide distribution of the RI normal values in the pig model, and our results do not support the normal ranges for RI and RIR, or the cut-off values used in clinical practice.