Prolonged enhancement of the micturition reflex in the cat by repetitive stimulation of bladder afferents

Efficacy in Using Urodynamic Parameters of Intravesical Electrical Stimulation for Detrusor Underactivity

OBJECTIVE

Intravesical electrical stimulation (IVES) remains a controversial therapy for detrusor underactivity (DUA). The purpose of this study is to determine the efficacy of IVES in patients with DUA using pre- and post-IVES urodynamic parameters.

METHODS

Intravesical electrical stimulation procedure is performed using a specific catheter equipped with an internal electrical electrode (cathode). The anode is subsequently affixed to the lower abdomen (suprapubic). Afterward, this specialized catheter is connected to a stimulator. Patients undergo a series of 12 IVES procedures in 1 month with the following predetermined parameters: 20 mA amplitude, 20 Hz frequency, 200 µs pulse width, and 60 minutes stimulation time. Patients underwent a follow-up urodynamic examination 1 month after the IVES series is completed.

RESULTS

After IVES, several notable changes were observed, including an increase in Qmax from 7.28 ± 5.24 to 7.29 ± 4.09 (P=.030), a decrease in post-void residual (PVR) from 73.03 ± 43.91 to 62.07 ± 39.10 (P=.005), and an increase in PDet@tQmax from 17.10 ± 12.35 to 18.87 ± 12.47 (P=.009). The aetiologies of DUA were categorized into 3 groups: chronic obstruction (CO), idiopathic (Idio), and neurological disorder (ND). The CO group exhibited significant changes in urodynamic parameters, specifically Qmax (P=.001), PVR (P=.001), and PDet@Qmax (P=.035). Similarly, the idiopathic group also demonstrated improvements in Qmax (P=.008), PVR (P=.037), and PDet@ Qmax (P=.033).

CONCLUSION

Intravesical electrical stimulation has been shown to have a positive effect on patients diagnosed with DUA, particularly those whose DUA is idiopathic or due to chronic obstruction.

Sympathetic afferents in the hypogastric nerve facilitate nociceptive bladder activity in cats

This study in α-chloralose-anesthetized cats revealed a role of hypogastric nerve afferent axons in nociceptive bladder activity induced by bladder irritation using 0.25% acetic acid (AA). In cats with intact hypogastric and pelvic nerves, AA irritation significantly ( P < 0.05) reduced bladder capacity to 45.0 ± 5.7% of the control capacity measured during a saline cystometrogram (CMG). In cats with the hypogastric nerves transected bilaterally, AA irritation also significantly ( P < 0.05) reduced bladder capacity, but the change was significantly smaller (capacity reduced to 71.5 ± 10.6% of saline control, P < 0.05) than that in cats with an intact hypogastric nerve. However, application of hypogastric nerve stimulation (HGNS: 20 Hz, 0.2 ms pulse width) to the central end of the transected nerves at an intensity (16 V) strong enough to activate C-fiber afferent axons facilitated the effect of AA irritation and further ( P < 0.05) reduced bladder capacity to 48.4 ± 7.4% of the saline control. This facilitation by HGNS was effective only at selected frequencies (1, 20, and 30 Hz) when the stimulation intensity was above the threshold for activating C-fibers. Tramadol (an analgesic agent) at 3 mg/kg iv completely blocked the nociceptive bladder activity and eliminated the facilitation by HGNS. HGNS did not alter non-nociceptive bladder activity induced by saline distention of the bladder. These results indicate that sympathetic afferents in the hypogastric nerve play an important role in the facilitation of the nociceptive bladder activity induced by bladder irritation that activates the silent C-fibers in the pelvic nerve.

Management of neurogenic bladder in patients with Parkinson's disease: A systematic review

AIMS

To assess the different treatment methods in management of neurogenic bladder (NGB) in patients with Parkinson's disease (PD).

METHODS

A systematic search was performed in Cochrane library, EMBASE, Proquest, Clinicaltrial.gov, WHO, Google Scholar, MEDLINE via PubMed, Ovid, ongoing trials registers, and conference proceedings in November 11, 2017. All randomized controlled trials (RCTs) or quasi-RCTs comparing any treatment method for management of NGB in patients with PD were included. The titles and abstracts of all identified studies were evaluated independently by two investigators. Once all of the potential related articles were retrieved, each author separately evaluated the full text of each article and the quality of the methodology of the selected studies using the Cochrane appraisal risk of bias checklist and then the data about the patient's outcomes was extracted. We registered the title in Joanna Briggs Institute (JBI) that is available in http://joannabriggs.org/research/registered_titles.aspx.

RESULTS

We included 41 RCTs or quasi-RCTs or three observational study with a total of 1063 patients that evaluated pharmacological, neurosurgical, botulinum toxin, electrical neuromodulation, and behavioral therapy effects on NGB. Among the included studies only solifenacin succinate double-blind, randomized, placebo-controlled study was assessed as low risk of bias, and treatment led to an improvement in urinary incontinence.

CONCLUSIONS

Although several interventions are available for treatment NGB in patients with PD, at present there is little or no evidence that treatment improves patient outcomes in this population. Additional large, well designed, randomized studies with improved methodology and reporting focused on patient-centered outcomes are needed.

Repeat periods of electrical stimulation prolong the modulation of the micturition reflex in the rat

AIMS

The aim of this study was to determine if the duration of the micturition reflex modulation could be prolonged by repeated periods of afferent stimulation in the decorticated rat.

METHODS

Eighteen female Sprague-Dawley rats were used for the study, 10 for intravesical electrical stimulation (IVES), and 8 for Ano-genital pudendal afferents stimulation. Repeated constant flow cystometries were performed with body-warm saline (0.06-0.1 mL/min) at about 10 min interval. The selected afferents were stimulated continuously for 5 min at maximal intensity. The same stimulation was repeated six times with a pause of 5 min between the stimulations. The mean threshold volume of cystometries performed during one hour before and each hour after the stimulation were compared.

RESULTS

After six periods of IVES, the micturition threshold volume decreased to its lowest value (62% of control) during the first hour and remained at 80% 4 h later (n = 10, P < 0.01). Ano-genital afferent stimulation produced a corresponding increase in the micturition threshold volume. The long-lasting poststimulation effect was again observed for more than 5 h. During the first hour the mean threshold volume increased to 211% of controls and it remained at about this level for the entire observation period (n = 8, P < 0.01).

CONCLUSIONS

Repeated short periods of stimulation prolonged the modulatory effect well beyond the stimulation period. The findings provide experimental evidence supporting the clinical application of IVES and ano-genital stimulation for treatment of neurogenic urinary bladder dysfunction.

Clinical efficacy of intravesical electrical stimulation on detrusor underactivity: 8 Years of experience from a single center

The aim of this study was to retrospectively evaluate the effectiveness of intravesical electrical stimulation (IVES) on detrusor underactivity (DU).From 2009 to 2016, a total of 105 patients with symptoms of DU who were treated with IVES were included in this retrospective study. The medical records, physical examination findings, urine culture results, and video-urodynamic studies were reviewed. Changes in post-void residual urine (PVR) and voiding efficiency (VE) were included for evaluation of efficacy. Patients achieving a >50% reduction in the PVR were regarded as responders. A >80% reduction in the PVR was considered obvious improvement. A questionnaire was administered to patients with bladder sensation.Of the 105 patients, the information of residual urine volume and voiding volume was obtained in 89 patients, and detailed pre- and post-IVES bladder sensation information was available on 96 patients. Of the 89 patients, 47.2% (42/89) were responders and achieved a >50% reduction in the PVR. Obvious improvement in the PVR, defined as a >80% reduction, occurred in 27% (24/89) of the patients. VE developed in 76.4% (68/89) of the patients, and 30.3% (27/89) of the patients increased >50%. Significant improvements in the PVR and VE were observed during IVES treatment (P < .05). Based on the questionnaire, bladder sensation developed and was sustained in 44.8% (43/96) of the patients.IVES provides a promising method for improving the PVR and VE in a majority of patients with DU. Thus, IVES is worth to further study and carry out.

Percutaneous Tibial Nerve Stimulation Therapy for Overactive Bladder Syndrome: Clinical Effectiveness, Urodynamic, and Durability Evaluation

OBJECTIVE

To evaluate percutaneous tibial nerve stimulation (PTNS) effectiveness, durability, and impact on the pathophysiology of overactive bladder syndrome (OAB) in patients who have been previously treated with antimuscarinics without success.

MATERIALS AND METHODS

A prospective study that included 200 women diagnosed with OAB between 2007 and 2015 at Virgen de la Victoria University Hospital (Málaga, Spain) was conducted. OAB patients were treated with PTNS therapy after antimuscarinic treatment failed. To evaluate OAB symptoms, clinical and urodynamic studies were performed before and after PTNS treatment. Treatment's success was defined as a reduction of clinical parameters by >50% and an improvement of at least 2 urodynamic parameters by >50%. The Kolmogorov-Smirnov test and Student's t test or Wilcoxon test were used based on the data. A linear correlation analysis and a multivariate linear regression analysis were performed to determine factors associated with the success of PTNS therapy.

RESULTS

Of the patients, 94% experienced a positive response to PTNS considering clinical and urodynamic parameters. PTNS benefits were extended by 24 months. We identified daytime urinary frequency (r = -0.165; P = .024; 95% confidence interval, -0.248 to -0.018) and first sensation of bladder filling (r = 0.208; P = .030; 95% confidence interval, 0.001-0.028) as significant independent predictor factors for PTNS success.

CONCLUSION

The current data confirmed a high effectiveness of PTNS improving OAB symptoms through 24 months. Furthermore, daytime urinary frequency and first sensation of bladder filling act as a significant independent predictor factors for PTNS success.

Efficacy of posterior tibial nerve stimulation in the treatment of children with primary mono-symptomatic nocturnal enuresis

Background/Aims:

Primary monosymptomatic nocturnal enuresis is the most frequent (85%) type of enuresis in children. However, there is limited research on the effect of posterior tibial nerve stimulation on monosymptomatic nocturnal enuresis in children. This study investigated the effect of posterior tibial nerve stimulation on primary monosymptomatic nocturnal enuresis in children.

Methods:

This controlled exposure study was conducted using a pretest–posttest design between March and December 2014. Participants (n=80) were randomly distributed to two study groups (control and intervention) using block randomisation. Participants in the control group were given and instructed on how to use a bedwetting alarm in addition to medical treatment for 12 weeks, whereas participants in the intervention group received posterior tibial nerve stimulation in addition to medical treatment for 12 weeks. The frequency of nocturnal enuresis, maximum voided volume and quality of life were evaluated before and after treatment.

Results:

Comparative analysis between pre- and post-treatment data revealed significant differences in both groups across all measured variables (p<0.05), with significant improvements in all three outcome measures found in the intervention group. Post-treatment, the intervention group demonstrated decreased frequency of nocturnal enuresis and improved maximum voided volume and quality of life.

Conclusions:

Posterior tibial nerve stimulation is an effective and safe approach for the treatment of primary monosymptomatic nocturnal enuresis and control of bedwetting in children.

Detrusor Underactivity: The Current Concept of the Pathophysiology

Based on evidence from available literature, we review the pathophysiology of detrusor underactivity (DU). DU is likely to be multifactorial. Aging reduces detrusor activity, but other concomitant causes may aggravate this condition, resulting in decrease of detrusor contractility. Impaired detrusor contractility has been regarded as a major etiologic factor of DU. However, a more complex pathology has been proposed. As contributing factors to DU, we discuss disturbances of the sensory afferent side of the micturition reflex, the central nervous system (CNS) and the efferent side of the reflex, including nerves and the detrusor muscle. Particularly, dysfunction of afferent nerves in the bladder and urethra may play a crucial role in the pathogenesis of DU. In addition, recent studies suggest that chronic bladder ischemia and resultant oxidative stress cause detrusor overactivity progressing to DU and inability to empty the bladder.

Purinergic signalling in the urinary tract in health and disease

Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder the purinergic component of parasympathetic cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

Percutaneous Tibial Nerve Stimulation (PTNS) efficacy in the treatment of lower urinary tract dysfunctions: a systematic review

Background

Percutaneous Tibial Nerve Stimulation (PTNS) has been proposed for the treatment of overactive bladder syndrome (OAB), non-obstructive urinary retention (NOUR), neurogenic bladder, paediatric voiding dysfunction and chronic pelvic pain/painful bladder syndrome (CPP/PBS). Despite a number of publications produced in the last ten years, the role of PTNS in urinary tract dysfunctions remains unclear. A systematic review of the papers on PTNS has been performed with the aim to better clarify potentialities and limits of this technique in the treatment of OAB syndrome and in other above mentioned urological conditions.

Methods

A literature search using MEDLINE and ISI web was performed. Search terms used were “tibial nerve” and each of the already mentioned conditions, with no time limits. An evaluation of level of evidence for each paper was performed.

Results

PTNS was found to be effective in 37-100% of patients with OAB, in 41-100% of patients with NOUR and in up to 100% of patients with CPP/PBS, children with OAB/dysfunctional voiding and patients with neurogenic pathologies. No major complications have been reported.

Randomized controlled trials are available only for OAB (4 studies) and CPP/PBS (2 studies). Level 1 evidence of PTNS efficacy for OAB is available. Promising results, to be confirmed by randomized controlled studies, have been obtained in the remaining indications considered.

Conclusions

PTNS is an effective and safe option to treat OAB patients. Further studies are needed to assess the role of PTNS in the remaining indications and to evaluate the long term durability of the treatment. Further research is needed to address several unanswered questions about PTNS.

Neural pathways involved in sacral neuromodulation of reflex bladder activity in cats

This study examined the mechanisms underlying the effects of sacral neuromodulation on reflex bladder activity in chloralose-anesthetized cats. Bladder activity was recorded during cystometrograms (CMGs) or under isovolumetric conditions. An S1-S3 dorsal (DRT) or ventral root (VRT) was electrically stimulated at a range of frequencies (1-30 Hz) and at intensities relative to threshold (0.25-2T) for evoking anal/toe twitches. Stimulation of DRTs but not VRTs at 1T intensity and frequencies of 1-30 Hz inhibited isovolumetric rhythmic bladder contractions. A 5-Hz DRT stimulation during CMGs was optimal for increasing (P < 0.05) bladder capacity (BC), but stimulation at 15 and 30 Hz was ineffective. Stimulation of the S1 DRT was more effective (increases BC to 144% and 164% of control at 1T and 2T, respectively) than S2 DRT stimulation (increases BC to 132% and 150% of control). Bilateral transection of the hypogastric or pudendal nerves did not change the inhibitory effect induced by S1 DRT stimulation. Repeated stimulation of S1 and S2 DRTs during multiple CMGs elicited a significant (P < 0.05) increase in BC (to 155 ± 11% of control) that persisted after termination of the stimulation. These results in cats suggest that the inhibition of reflex bladder activity by sacral neuromodulation occurs primarily in the central nervous system by inhibiting the ascending or descending pathways of the spinobulbospinal micturition reflex.

Post-stimulation inhibitory effect on reflex bladder activity induced by activation of somatic afferent nerves in the foot

PURPOSE

We determined whether transcutaneous electrical stimulation of somatic afferent nerves in the foot of cats would induce a post-stimulation increase in bladder capacity.

MATERIALS AND METHODS

In 12 α-chloralose anesthetized cats electrical stimulation (5 Hz) was applied to the skin of the hind foot for 2, 30-minute periods via dual pad electrodes attached on the plantar and dorsal surfaces (combination 1 and 2) or at 2 sites on the plantar surface (combination 1 and 3). The post-stimulation effect was examined by repeat cystometrogram after 30-minute stimulation. In the control group of 12 cats isovolumetric contractions were allowed to continue during each 30-minute period without stimulation.

RESULTS

Stimulation inhibited isovolumetric rhythmic bladder contractions. Bladder capacity was not increased after the first 30-minute foot stimulation via electrodes 1 and 2 but it was significantly increased a mean ± SE of 47.5% ± 2.9% after the second 30-minute stimulation via electrodes 1 and 3. After inducing the post-stimulation effect the foot stimulation applied during cystometrograms via electrodes 1 and 2 or 1 and 3 elicited a further increase in bladder capacity (mean 23.26% ± 17.64% and 20.07% ± 18.59%, respectively).

CONCLUSIONS

Results show that the transcutaneous plantar electrical stimulation of somatic afferent nerves in the foot can induce a post-stimulation increase in bladder capacity, suggesting that an intermittent stimulation pattern rather than continuous stimulation might be effective as clinical application to treat overactive bladder symptoms.

Electrical stimulation of the urethra evokes bladder contractions and emptying in spinal cord injury men: case studies

OBJECTIVE

Electrical stimulation of the urethra can evoke bladder contractions in persons with spinal cord injury (SCI). The objective of this study was to determine whether electrical stimulation of the urethra could evoke bladder contractions that empty the bladder.

METHODS

The first patient was a 45-year-old man with a T6 ASIA A SCI secondary to a gunshot wound 15 years prior. The second patient was a 51-year-old man with a T2 ASIA A SCI secondary to a fall from scaffolding 2 years prior. Both patients demonstrated neurogenic detrusor overactivity on urodynamics and managed their bladder with clean intermittent catheterization and oxybutynin medication. Following informed consent, each patient discontinued oxybutynin 2 days prior to urodynamic testing. Urodynamics were performed with a custom 12 French balloon catheter mounted with ring-shaped electrodes (3 mm) positioned in the prostatic urethra. After filling the bladder to approximately three-fourth of capacity at a rate of 25 ml/minute, the urethra was stimulated with a range of parameters to determine whether electrical stimulation could evoke a bladder contraction and empty the bladder.

RESULTS

Electrical stimulation of the prostatic urethra evoked bladder contractions (peak detrusor pressures of 60-80 cm H(2)O) that emptied the bladder in both subjects. In the first subject, stimulation (9-12 mA, 20 Hz) emptied 64-75%, leaving post-void residual volumes (PVRs) of 41-20 ml. In the second subject, stimulation (20 mA, 20 Hz) emptied 68-77%, leaving PVRs of 56-45 ml.

CONCLUSION

Urethral stimulation evoked bladder emptying in persons with SCI.

Neuromodulation of bladder activity by stimulation of feline pudendal nerve using a transdermal amplitude modulated signal (TAMS)

AIM

To develop a non-invasive neuromodulation method to regulate bladder activity.

METHODS

Neuromodulation of bladder activity was investigated in felines with an intact spinal cord under α-chloralose anesthesia using a transcutaneous stimulation method with surface electrodes attached to the skin area between the base of the tail and the sciatic notch.

RESULTS

The bladder could be either inhibited or excited depending on stimulation frequency and bladder volume. With the bladder distended to induce large amplitude rhythmic isovolumetric bladder contractions, stimulation at a frequency between 5 and 7  Hz significantly suppressed the contractions. Stimulation applied during a cystometrogram (CMG) also increased bladder capacity by 44.3  ±  10.8%. At a frequency between 20 and 40  Hz the inhibitory effect on rhythmic bladder contractions was weak and did not increase bladder capacity during CMG. At low bladder volumes ranging between 60% and 100% of the bladder capacity 20  Hz stimulation-induced small amplitude (21.2  ± 14.6  cmH(2) O) bladder contractions. However, stimulation at 20  Hz induced large amplitude (111.7  ±  22.2  cmH(2) O) bladder contractions at a bladder volume about 100-110% of the bladder capacity after the rhythmic bladder contractions were completely inhibited by the inhibitory 5  Hz stimulation.

CONCLUSIONS

Both inhibitory and excitatory effects on bladder activity can be obtained in cats using the non-invasive neural stimulation approach. This pre-clinical study warrants a further clinical trial to investigate the possibility of using this non-invasive stimulation method to treat incontinence or urinary retention.

Aging and the underactive detrusor: a failure of activity or activation?

AIMS

To examine the known and potential contributions of motor, sensory, and biomechanical dysfunctions to the clinical problems of detrusor underactivity and detrusor hyperactivity/impaired contractility.

METHODS

A review of the current literature on non-obstructive voiding dysfunction associated with aging was conducted. The functional impact of age-induced biomechanical tissue change via alterations in sensory transduction is considered.

RESULTS

Impaired contractility has been regarded as etiologic of detrusor underactivity. However, an age-related degradation in detrusor contractility as the primary contributor to impaired bladder emptying has not been conclusively demonstrated. To the extent that detrusor contraction force and duration are dependent upon efferent nerve activity and thus reflex responses to sensory activity, there is a potential impact of impaired sensory function on voiding efficiency. Structural and functional tissue changes accompanying aging may result in altered bladder afferent function, with subsequent reflex impairment of detrusor voiding function.

CONCLUSIONS

The relative contributions of motor, sensory, and biomechanical dysfunctions to impaired voiding performance independent of outlet obstruction associated with aging remain to be elucidated.

Neural control of the lower urinary tract: peripheral and spinal mechanisms

This review deals with individual components regulating the neural control of the urinary bladder. This article will focus on factors and processes involved in the two modes of operation of the bladder: storage and elimination. Topics included in this review include: (1) The urothelium and its roles in sensor and transducer functions including interactions with other cell types within the bladder wall ("sensory web"), (2) The location and properties of bladder afferents including factors involved in regulating afferent sensitization, (3) The neural control of the pelvic floor muscle and pharmacology of urethral and anal sphincters (focusing on monoamine pathways), (4) Efferent pathways to the urinary bladder, and (5) Abnormalities in bladder function including mechanisms underlying comorbid disorders associated with bladder pain syndrome and incontinence.

Intraurethral stimulation for reflex bladder activation depends on stimulation pattern and location

AIMS

Reflex bladder excitation has been demonstrated by stimulation of the pudendal nerve and several of its distal branches. However, excitation parameters have not been consistent and the relationship to anatomical locations within the urethra has not been fully investigated. An improved understanding of the lower urinary tract neurophysiology will improve human studies and neuroprosthetic device development.

METHODS

Intraurethral stimulation was performed in nine cats at near isovolumetric bladder volumes before and/or after spinalization. Bladder excitability profiles were obtained for lower (2 Hz) and higher (33 Hz) frequency stimuli along the urethra between the bladder neck and external meatus.

RESULTS

Higher frequency stimuli were excitable at all urethral locations prior to spinalization but only excitable in the middle and distal urethra after spinalization. Lower frequency stimuli were excitable at proximal and middle locations before spinalization but not excitable at any location after spinalization. In most evaluations, bursting pulse stimulation patterns evoked greater bladder pressures than the dominant continuous frequency (2 or 33 Hz).

CONCLUSIONS

These data indicate the potential presence of two distinct pathways for reflex bladder activation within the urethra: a supra-T10 circuit initiated in the proximal and mid urethra that responds to lower and higher frequency stimuli, and a sacral circuit initiated in the mid and distal urethra that responds to higher frequency stimuli. This work suggests potential anatomical targets and stimulus patterns for clinical evaluations of peripheral nerve-based neuroprostheses for bladder control.

Variable patterned pudendal nerve stimuli improves reflex bladder activation

We evaluated variable patterns of pudendal nerve (PN) stimuli for reflex bladder excitation. Reflex activation of the bladder has been demonstrated previously with 20-33 Hz continuous stimulation of PN afferents. Neuronal circuits accessed by afferent mediated pathways may respond better to physiological patterned stimuli than continuous stimulation. Unilateral PN nerve cuffs were placed in neurologically intact male cats. PN stimulation (0.5-100 Hz) was performed under isovolumetric conditions at bladder volumes up to the occurrence of distension evoked reflex contractions. Stimulus evoked reflex bladder contractions were elicited in eight cats. Across all experiments, bursting of 2-10 pulses at 100-200 Hz repeated at continuous stimulation frequencies evoked significantly larger bladder responses than continuous (single pulse) stimulation (52.0+/-44.5%). Bladder excitation was also effective at 1 Hz continuous stimuli, which is lower than typically reported. Variable patterned pulse bursting resulted in greater evoked reflex bladder pressures and increased the potential stimulation parameter space for effective bladder excitation. Improved bladder excitation should increase the efficacy of neuroprostheses for bladder control.

Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

Urinary retention is the inability to empty the bladder completely, and may result from bladder hypocontractility, increases in outlet resistance or both. Chronic urinary retention can lead to several urological complications and is often refractory to pharmacologic, behavioral and surgical treatments. We sought to determine whether electrical stimulation of sensory fibers in the pudendal nerve could engage an augmenting reflex and thereby improve bladder emptying in an animal model of urinary retention. We measured the efficiency of bladder emptying with and without concomitant electrical stimulation of pudendal nerve afferents in urethane-anesthetized rats. Voiding efficiency (VE = voided volume/initial volume) was reduced from 72 +/- 7% to 29 +/- 7% following unilateral transection of the sensory branch of the pudendal nerve (UST) and from 70 +/- 5% to 18 +/- 4% following bilateral transection (BST). Unilateral electrical stimulation of the proximal transected sensory pudendal nerve during distention-evoked voiding contractions significantly improved VE. Low-intensity stimulation at frequencies of 1-50 Hz increased VE to 40-51% following UST and to 39-49% following BST, while high-intensity stimulation was ineffective at increasing VE. The increase in VE was mediated by increases in the duration of distention-evoked voiding bladder contractions, rather than increases in contraction amplitude. These results are consistent with an essential role for pudendal sensory feedback in efficient bladder emptying, and raise the possibility that electrical activation of pudendal nerve afferents may provide a new approach to restore efficient bladder emptying in persons with urinary retention.

Inhibitory and excitatory perigenital-to-bladder spinal reflexes in the cat

This study revealed that in awake chronic spinal cord-injured (SCI) cats reflexes from perigenital skin area to the bladder can be either inhibitory or excitatory. Electrical perigenital stimulation at frequencies between 5 and 7 Hz significantly inhibited large-amplitude rhythmic reflex bladder activity, whereas frequencies between 20 and 40 Hz induced large-amplitude bladder contractions even at low bladder volumes when reflex bladder activity was absent. Both inhibitory and excitatory effects were enhanced as the stimulation intensity increased (5-30 V, 0.2-ms pulse width). During cystometrograms, the inhibitory stimulation (7 Hz) significantly increased the micturition volume threshold 35 +/- 13% above the control volume, while the excitatory stimulation (30 Hz) significantly reduced the threshold 21 +/- 3%. Mechanical perigenital stimulation applied by repeated light stroking of the perigenital skin with a cotton swab only induced an excitatory effect on the bladder. Both electrical and mechanical perigenital stimuli induced large-amplitude (>30 cm H(2)O) bladder contractions that were relatively consistent over a range of bladder volumes (10-90% of the capacity). However, the excitatory electrical stimulation only induced bladder contractions lasting on average 42.2 +/- 3.9 s, but the mechanical stimulation induced bladder contractions that lasted as long as the stimulation continued (2-3 min). Excitatory electrical or mechanical perigenital stimulation also induced poststimulus voiding. The ability to either inhibit or excite the bladder by noninvasive methods could significantly transform the current clinical management of bladder function after SCI.

Dorsal genital nerve stimulation for the treatment of overactive bladder symptoms

AIM

To evaluate percutaneous placement of electrodes adjacent to the dorsal genital nerve (DGN) and measure the effects of electrical stimulation on symptoms of urge incontinence during 1 week of home use.

METHODS

Prospective, multicenter study. Subjects with urge incontinence underwent percutaneous placement of an electrode using local anesthetic. Test stimulation was applied to confirm electrode placement and cystometry was conducted with and without application of electrical stimulation. A 7-day testing period with the electrode connected to an external pulse generator was performed and was followed by a 3-day post-treatment test period. Bladder diaries, 24 hr pad tests, and adverse event queries were obtained.

RESULTS

Twenty-one women were enrolled with an average age of 52.7 years and average duration of incontinence of 6 years. Percutaneous electrode placement required 5-10 min and was well tolerated. There was no relationship between the acute effects of stimulation on cystometry and the results during home use. Pad weight was reduced by >or= 50% in 13 of 17 subjects (76%) (4 did not complete 24 hr pad testing) and 47% of subjects reported >or=50% reduction in incontinence episodes. Of the subjects who reported severe urgency at baseline, 81% experienced a 50% or greater improvement. Seven subjects experienced nine adverse events ranging from skin irritation to pain and bruising around the electrode exit site.

CONCLUSIONS

Electrodes to stimulate the DGN can be placed percutaneously and a home testing period showed a reduction in overactive bladder symptoms with DGN stimulation.

Spinal glutamatergic NMDA-dependent pelvic nerve-to-external urethra sphincter reflex potentiation caused by a mechanical stimulation in anesthetized rats

The current study investigates whether the spinal pelvic nerve-to-external urethra sphincter (EUS) reflex potentiation can be induced by a mechanical stimulation and whether the glutamatergic mechanism is involved in yielding such a reflex potentiation. The external urethra sphincter electromyogram (EUSE) activity, evoked by a single or by repetitive pelvic nerve stimulation, in 30 anesthetized rats was recorded with/without bladder saline distension. Without saline distension (0 cmH2O), a single pulse nerve stimulation evoked a single action potential in the reflex activity, whereas repetitive pelvic stimulation and saline distension (6∼20 cmH2O) both elicited a long-lasting reflex potentiation (20.05 ± 3.21 and 75.01 ± 9.87 spikes/stimulation, respectively). The saline distension-induced pelvic nerve-to-EUS reflex potentiation was abolished by d-2-amino-5-phosphonovalerate [APV; a glutamatergic N -methyl-d-aspartic acid (NMDA) receptor antagonist; 100 μM, 10 μl, 1.72 ± 0.31 spikes/stimulation] and attenuated by 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline [NBQX; a glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazoleproprionate (AMPA) receptor antagonist; 100 μM, 10 μl, 26.16 ± 7.27 spikes/stimulation], but was not affected by bicuculline (a GABAergic antagonist; 100 μM, 10 μl, 53.62 ± 15.54 spikes/stimulation). Intrathecal administration of glutamate (31.12 ± 8.25 spikes/stimulation, 100 μM, 10 μl) and NMDA (26.25 ± 4.12 spikes/stimulation, 100 μM, 10 μl) both induced a long-lasting pelvic nerve-to-EUS reflex potentiation without saline distension, which was similar to the findings observed from saline distension only. The duration of the contraction wave of the urethra was elongated by the saline distension-induced pelvic nerve-to-EUS reflex potentiation, whereas the peak pressure of the contraction wave was not affected. Our findings suggest that saline distension in the bladder elicits a pelvic nerve-to-EUS reflex potentiation and the glutamatergic mechanism contributes to the presence of such a reflex potentiation.

Topographic anatomy of a new posterior approach to the pudendal nerve for stimulation

OBJECTIVES

To describe a new approach to the pudendal nerve from a dorsal direction in terms of topographic anatomy and to discuss pudendal nerve neurophysiology in light of the rationale behind pudendal nerve stimulation to treat lower urinary tract disorders.

MATERIALS AND METHODS

Cadavers of four women aged 78-87 yr were studied. After placing the cadavers in prone position with a 40 degrees -60 degrees flexion of the hips and determining anatomic landmarks, a 20-G insulated needle was inserted close to the pudendal nerve. Then the topographic relationships of the puncture with the pudendal canal were explored by dissection.

RESULTS

The mean points of insertion of the needle were 14 cm inside the great trochanter, 9 cm above the ischiatic tuberosity, and 6 cm outside the gluteal fold. If the needle was inserted 6.5 cm under the previous with an orifice of 60 degrees and this route was followed, the needle could have a contact area with the pudendal nerve larger, leading to a greater stimulation efficacy with less stimulation intensities. The rectum was so far away that a rectal injury with the needle seemed unlikely. No vascular structure was at the contact of the nerve.

CONCLUSIONS

The described new puncture technique to reach the pudendal nerve provides easy and safe accessibility of the nerve for stimulation. In light of our increasing understanding of the rationale behind neuromodulative stimulation, the pudendal nerve could be a promising target for continuous lower urinary tract neuromodulation by implant.

Frequency-dependent selection of reflexes by pudendal afferents in the cat

Activation of urethral or genital afferents of the pudendal nerve can elicit or inhibit micturition, and low frequency stimulation of the compound pudendal nerve (PN) is known to produce a continence response. The present study demonstrates that PN stimulation also can elicit a micturition-like response and that the response to PN stimulation is dependent on stimulation frequency. We measured the changes in bladder pressure and external urethral sphincter (EUS) electroneurogram (ENG) evoked by PN stimulation before and up to 16 h after spinal cord transection (SCT) in cats anaesthetized with alpha-chloralose. Low frequency (10 Hz) stimulation elicited a continence-like response, including inhibition of the bladder and activation of the EUS, but mid-frequency (33 Hz) stimulation produced a micturition-like response, including excitation of the bladder without activation of the EUS. The dependence of the response on stimulus frequency was linked to interpulse interval as the same number of pulses at 10, 33 and 100 Hz produced different responses. Stimulation of the PN at 33 Hz produced bladder contractions before and 8 h after SCT provided the bladder contained a minimum volume of fluid. Only mid-range frequency stimulation with sufficient stimulus train duration produced a reduction in EUS ENG activity before and after SCT. In addition to a continence-like response, PN stimulation can also elicit a micturition-like response, and this response is dependent on stimulation frequency, stimulus train duration, and bladder volume. The ability to control the two principal functions of the bladder by pudendal nerve stimulation is an exciting prospect for neurorehabilitation.

Recurrent inhibition of the bladder C fibre reflex in the cat and its response to naloxone

Recurrent inhibition of the bladder C fibre reflex was studied in adult female cats anaesthetized with alpha-chloralose. Test reflexes were evoked by electrical stimulation of bladder Adelta and C afferents in the right pelvic nerve and were recorded from the proximal end of a small ipsilateral pelvic nerve branch, transected close to the bladder. Such test reflexes were consistently depressed by repetitive electrical stimulation of the contralateral bladder pelvic nerve (20 Hz, 20 s) at intensities sufficient to recruit axons of bladder preganglionic neurones. The inhibition could be evoked after transection of the left dorsal roots S1-S4 and the sympathetic supply to the bladder but was abolished by transection of the pelvic nerve central to the site of stimulation. Hence, it most likely involved central recurrent collaterals of antidromically activated bladder preganglionic neurones. The reflex suppression was quite considerable - maximal C fibre reflexes were reduced to a group mean of 25% (+/- 9% confidence interval) of their control size. The effect had a slow onset, requiring a few seconds of conditioning stimulation to be revealed, and was very long lasting (minutes). Naloxone (0.01-0.5 mg kg(-1) i.v.) abolished the recurrent inhibition of both the C fibre and Adelta bladder reflexes, while inhibition from afferents in the dorsal clitoris nerve remained unchanged. It is concluded that the segmental bladder C fibre reflex and the spino-ponto-spinal Adelta micturition reflex are both targets of recurrent inhibition from bladder parasympathetic preganglionic neurones and that the effect involves an enkephalinergic mechanism.

Sacral neuromodulation in lower urinary tract dysfunction

Vesico-urethral dysfunction is a major problem in daily medical practice due to its psychological disturbances, its social costs and its high impact on quality of life. Recently, sacral neuromodulation, namely the electrical stimulation of the sacral nerves, appears to have become an alternative for radical bladder surgery particularly in cases of idiopathic bladder overactivity. The mechanism of action is only partially understood but it seems to involve a modulation in the spinal cord due to stimulation of inhibitory interneurons. Temporary sacral nerve stimulation is the first step. It comprises the temporary application of neuromodulation as a diagnostic test to determine the best location for the implant and to control the integrity of the sacral root. If test stimulation is successful, a permanent device is implanted. This procedure is safe in experienced hands. So-called idiopathic bladder overactivity still the major indication for this technique. Patients not likely to benefit from the procedure were those with complete or almost complete spinal lesions, but incomplete spinal lesions seemed to be a potential indication. This technique is now also indicated in the case of idiopathic chronic retention and chronic pelvic pain syndrome. When selection is performed, more than three-quarters of the patients showed a clinically significant response with 50% or more reduction in the frequency of incontinent episodes, but the results vary according to the author's mode of evaluation. From the economic point of view, the initial investment in the device is amortized in the mid-term by savings related to lower urinary tract dysfunction. Finally, this technique requires an attentive follow-up and adjustments to the electric parameters so as to optimize the equilibrium between the neurological systems.

Spinal micturition reflex mediated by afferents in the deep perineal nerve

Reflexes mediated by urethral sensory pathways are integral to urinary function. This study investigated the changes in bladder pressure and urethral sphincter activity resulting from electrical stimulation of afferents in the deep perineal nerve (DP), which innervates the urethra and surrounding muscles, before and after acute spinal cord transection (SCT) in cats anesthetized with alpha-chloralose monitored by blood pressure and heart rate. DP stimulation elicited bladder contractions before and after SCT but only if the bladder contained a sufficient volume of fluid (78% of the volume needed to cause distention-evoked reflex contractions). The volume dependency was mediated by a neuronal mechanism in the lumbosacral spinal cord and was not attributable to length-tension properties of the detrusor muscle. Stimulation at 2-40 Hz initiated bladder contractions, but 20-40 Hz was more effective than lower frequencies in evoking and sustaining bladder contractions for the duration of the stimulus train. Decreases in urethral sphincter activity occurred during sustained bladder contractions evoked by 20- to 40-Hz stimulation before and within 16 h after SCT. After SCT, average bladder pressure increases evoked by DP stimulation were smaller than those evoked before SCT, but in some animals, bladder pressures elicited by DP stimulation continued to increase as time after SCT increased and reached pretransection amplitudes at 8-16 h posttransection. These data confirm the presence of a spinal circuit that can mediate coordinated bladder-sphincter responses and show that afferents from the DP can activate this circuit under appropriate conditions.

A urethral afferent mediated excitatory bladder reflex exists in humans

An excitatory reflex between urethral flow receptors and the bladder has been established in animals, but attempts to demonstrate this reflex in humans using urethral fluid flow have been inconclusive. Intraurethral electrical stimulation has recently been shown to generate bladder contractions in animals and was applied to study the presence of an excitatory urethra to bladder reflex in humans. The prostatic urethra was stimulated electrically via a catheter-based electrode in five men with complete spinal cord injury. Bladder contractions were generated in four of five individuals, however, only when the bladder volume was sufficiently large. These results demonstrate the presence of a volume dependent excitatory bladder reflex mediated by urethral afferent nerve fibers and the lumbosacral spinal cord.

Artificial autonomic reflexes: using functional electrical stimulation to mimic bladder reflexes after injury or disease

Autonomic reflexes controlling bladder storage (continence) and emptying (micturition) involve spinal and supraspinal nerve pathways, with complex mechanisms coordinating smooth muscle activity of the lower urinary tract with voluntary muscle activity of the external urethral sphincter (EUS). These reflexes can be severely disrupted by various diseases and by neurotrauma, particularly spinal cord injury (SCI). Functional electrical stimulation (FES) refers to a group of techniques that involve application of low levels of electrical current to artificially induce or modify nerve activation or muscle contraction, in order to restore function, improve health or rectify physiological dysfunction. Various types of FES have been developed specifically for improving bladder function and while successful for many urological patients, still require substantial refinement for use after spinal cord injury. Improved knowledge of the neural circuitry and physiology of human bladder reflexes, and the mechanisms by which various types of FES alter spinal outflow, is urgently required. Following spinal cord injury, physical and chemical changes occur within peripheral, spinal and supraspinal components of bladder reflex circuitry. Better understanding of this plasticity may determine the most suitable methods of FES at particular times after injury, or may lead to new FES approaches that exploit this remodeling or perhaps even influence the plasticity. Advances in studies of the neuroanatomy, neurophysiology and plasticity of lumbosacral nerve circuits will provide many further opportunities to improve FES approaches, and will provide "artificial autonomic reflexes" that much more closely resemble the original, healthy neuronal regulatory mechanisms.

A review of non-invasive electro neuromodulation as an intervention for non-neurogenic bladder dysfunction in children

AIMS

The use of electrotherapeutics to improve filling and emptying dysfunction of the adult bladder has been well established, however the practice in children is less well known. The purpose of this review is to summarize the rationale behind the use of electro neuromodulation in children, examine the reported efficacy of the intervention for different presentations of dysfunction, and establish the current limitations to knowledge and practice.

MATERIALS AND METHODS

A modified systematic review was carried out on all Medline studies identified as considering the use of electrotherapy or neuromodulation in children with bladder problems. Literature relating to use of this approach in adults was also searched in order to present current understanding of the treatment rationale and modes of application.

RESULTS

A Medline search and handsearch of relevant conference proceedings revealed six studies of neuromodulation in children with non-neurogenic bladder dysfunction. There were no reports of the intervention in children with isolated pelvic floor dyssynergia, irritative symptoms, structural changes predisposing the pelvic floor to weakness, or monosymptomatic nocturnal enuresis. One report of the favorable effect of neuromodulation on gut dysmotility was identified. Study design and quality generated level 4 evidence. Positive post-intervention changes reported included: increased bladder capacity, decreased severity of urge, improved continence, and decrease frequency of urinary tract infection. Significant improvement in the urodynamic parameters of bladder compliance, number of uninhibited contractions, and bladder volume at first detrusor contraction were also reported.

CONCLUSIONS

There are clear benefits from the use of electroneuromodulation in children with differing forms of voiding dysfunction. The treatment approach is independent of cognitive and pharmacological therapy, is minimally invasive, and free of side effects. To date, there are no clinical variables that reliably predict efficacy of electrotherapy in the various presentations of over and under active detrusor, sphincter dyssynergia, or irritative symptoms.

Posterior tibial nerve stimulation in the treatment of voiding dysfunction: Urodynamic data

OBJECTIVES

To determine urodynamic changes and predictive factors in patients with voiding dysfunction who underwent 12 percutaneous tibial nerve stimulations.

METHODS

Thirty nine patients with chronic voiding dysfunction were enrolled in a prospective multicenter trial in the Netherlands (n = 19) and in Italy (n = 20). A 50% reduction in total catheterised volume per 24 hr was taken as a primary objective outcome measure. Patients' request for continuation of treatment was regarded as subjective success. Objective urodynamic parameters and bladder indices were determined. Odds ratios and their 95% confidence interval were computed as a measure for predictive power in order to reveal predictive factors (Pdet at Qmax, Qmax, BVE, and BCI).

RESULTS

Primary outcome measure was obtained in 41%, an additional 26% reduced their 24 hr residuals with more than 25%. Fifty nine percent of patients chose to continue treatment. Detrusor pressure at maximal flow, cystometric residuals, and bladder indices improved significantly for all patients (P < 0.05). Patients with minor voiding dysfunction were more prone to notice success (Odds ratio: 0.73; 95% CI: 0.51-0.94).

CONCLUSIONS

PTNS is a young treatment modality, minimally invasive, and easily accessible. It might be an attractive first line option for patients with (minor) voiding dysfunction.

Afferent fibers of the pudendal nerve modulate sympathetic neurons controlling the bladder neck

AIMS

Pudendal nerve stimulation is known to have a potential modulative effect on bladder function. However, even if its efficiency has been established for various neurogenic and non-neurogenic bladder dysfunctions, the underlying neuronal mechanism, and the involved pathways in humans remain unknown. In this prospective study we focused on the effects of pudendal nerve stimulation in complete spinal cord injured patients to identify neuromodulative processes that occur on spinal level.

METHODS

Twenty complete spinal male presenting with upper motor neuron lesion and neurogenic incontinence underwent pudendal nerve stimulation. Bladder, bladder neck (BN), and external urethral sphincter (EUS) pressures were continuously recorded with a three channel microtip pressure transducer catheter. Fifty six pudendal stimulations using biphasic rectangular impulses (0.2 ms, 10 Hz) with intensities up to 100 mA were applied to the dorsal penile nerve. In six patients, 18 stimulations were repeated after intravenous (i.v.) administration of 7 mg phentolamine.

RESULTS

Mean BN and EUS pressure increased during stimulation significantly (P < 0.001). The latencies to the EUS responses range between 27 and 41 ms and those to the BN responses between 188 and 412 ms. Phentolamine decreased initial BN pressure and reduced the pressure rise during stimulation significantly (P < 0.05).

CONCLUSIONS

Pudendal nerve stimulation evoked somatic responses in the EUS and autonomic responses in the smooth muscle sphincter controlling the BN. Longer latencies of the BN responses and the sensitivity to the alpha-blocking agent phentolamine suggest that sympathetic alpha-adrenergic fibers are involved. Somatic afferent fibers of the pudendal nerve are supposed to project on sympathetic thoracolumbar neurons to the BN and modulate their function. This neuromodulative effect works exclusively at the spinal level and appears to be at least partly responsible for BN competence and at least continence.

Intravesical electrical stimulation in the treatment of micturition dysfunction in children

AIMS

To evaluate the results of intravesical electrical stimulation (IVES) in an open prospective study to treat underactive detrusor in children. The treatment was offered as an alternative to clean intermittent catheterization (CIC).

METHODS

Forty-four children were included, 21 girls and 3 boys (6-16 years, md 10) with idiopathic, 9 girls and 11 boys (4-18 years; md 13) with neurogenic underactive detrusor. IVES was given by a catheter electrode in the bladder (cathode) with the anode attached to the suprapubic abdominal skin. Continuous stimulation at 20 or 25 Hz was delivered by battery powered stimulators giving unipolar square-wave pulses (0,2 or 0,7 ms). Stimulation intensity was adjusted individually according to the acceptance of the child (12-64 mA). IVES was initially given at the clinic but 18 children had additional treatment at home. Effect of treatment was monitored by micturiton/incontinence diary, reports of bladder sensation, recordings of urinary flow, residual volume and frequency of urinary tract infections.

RESULTS

The IVES-treatment was completed by 39/44 children. Long term normalization of the voiding (md 2,5 years follow up) was obtained for 20/24 children with idiopathic problems (83%) and 8/20 with neurogenic problems (40%). Another four had much improved bladder function. The neurogenic group required more stimulation sessions than the idiopathic group. Of those on CIC, 11/15 who completed IVES could discontinue the catheterization. The frequency of urinary tract infections and incontinence decreased significantly (P < 0.01).

CONCLUSIONS

It is concluded that IVES is a promising method to treat the underactive detrusor in children.

A catheter based method to activate urethral sensory nerve fibers

PURPOSE

The ability to control bladder activity would provide a valuable tool to assist individuals with neurological disorders or spinal cord injury (SCI). Recent studies in animal models have shown that bladder contractions can be evoked by electrical stimulation of urethral afferent nerves. We developed and validated in cats a minimally invasive method to stimulate electrically the sensory nerve fibers that innervate the urethra.

MATERIALS AND METHODS

The urethra was stimulated electrically along its length via a catheter mounted circumferential electrode in 6 cats. The urethra was similarly stimulated in a male individual with complete SCI.

RESULTS

Robust bladder contractions were generated via intraurethral electrical stimulation in all cat experiments. Peak responses were obtained in the proximal and prostatic urethra. In the individual with SCI bladder contractions were generated via intraurethral stimulation at a position 4 cm distal to the bladder. Responses in cats and the human depended on bladder volume.

CONCLUSIONS

To our knowledge this study provides the first documentation of generating bladder contractions via intraurethral electrical stimulation in cats and humans. This method provides a research tool for future studies to investigate these pathways in humans. Preliminary human results suggest that urethral afferent mediated neural pathways demonstrated in animal models exist in humans and support the development of neural prostheses using electrical stimulation of these nerves to restore control of bladder function in individuals with neurological disorders or SCI.

Posterior tibial nerve stimulation in the treatment of urge incontinence

AIMS

The objective of this study was to evaluate the effect of posterior tibial nerve stimulation (PTNS) for treatment of urge incontinence.

METHODS

In a prospective multicentre study, 35 patients with complaints of urge incontinence underwent 12 weekly sessions of PTNS at one of five sites in the Netherlands and one site in Italy. Frequency/volume charts and I-QoL and SF-36 questionnaires were completed at 0 and 12 weeks. Success was analysed by using subjective and objective criteria. Overall subjective success was defined as the willingness to continue treatment, whereas objective success was defined as a significant decrease (to<50%) in total number of leakage episodes.

RESULTS

Twenty-two patients (63%) reported a subjective success. Twenty-four patients (70%) showed a 50% or greater reduction in total number of leakage episodes. Sixteen (46%) of these-patients were completely cured (i.e., no leakage episodes) after 12 sessions. Quality of life parameters improved significantly.

CONCLUSIONS

We conclude that posterior tibial nerve stimulation is an effective, minimally invasive option for treatment of patients with complaints of urge incontinence, as improvement was seen in subjective as well as objective parameters.

Posterior tibial nerve stimulation in the treatment of idiopathic nonobstructive voiding dysfunction

OBJECTIVES

To evaluate the effect of stimulation of the posterior tibial nerve in the treatment of voiding dysfunction.

METHODS

Thirty-nine patients with chronic voiding dysfunction necessitating clean intermittent catheterization were enrolled in a prospective multicenter trial in the Netherlands (n = 19) and Italy (n = 20). They underwent 12 weekly sessions of posterior tibial nerve stimulation. Frequency/volume charts, an incontinence quality-of-life instrument, and the MOS 36-item Short-Form Health Survey were completed at 0 and 12 weeks. Subjective success was defined by the patient's positive response resulting in a request to continue treatment. Efficacy was based on analysis of the frequency/volume charts comparing the baseline values with the data at 12 weeks. A reduction of 50% or more in total catheterized volume was considered as an objective success (primary outcome measurement).

RESULTS

Of the 39 patients, 23 (59%) chose to continue treatment. The frequency/volume charts showed a 50% decrease in total catheterized volume in 16 (41%) of 39 patients. Additionally, 10 patients (26%) noted a reduction of 25% to 50% in their total catheterized volume. For all patients, the total catheterized volume decreased by a mean of -228 mL (range -49 to -528). The incontinence quality-of-life instrument and Short-Form Health Survey parameters improved significantly.

CONCLUSIONS

Percutaneous stimulation of the posterior tibial nerve seems to be an effective, minimally invasive option worth trying in patients with idiopathic voiding dysfunction. Improvement was seen in objective micturition parameters, as well as in subjective quality-of-life data.

Anogenital electrical stimulation as treatment of urge incontinence in children

OBJECTIVES

To evaluate retrospectively the result of anogenital afferent stimulation (AGAS) in neurological healthy children with therapy-resistant urge incontinence.

PATIENTS AND METHODS

The study included 48 children (24 girls and 24 boys, 5-14 years old) with a diagnosis of bladder instability verified by cystometry in all. Anogenital afferent stimulations were applied using a battery-powered dual constant-current stimulator. The children were stimulated continuously at 10 Hz for 20 min once or twice daily and if required the children and/or the parents continued to apply the treatment at home. For home stimulation a single (anal) channel stimulator was used. The patients were instructed to stimulate for 20 min at maximum intensity two to three times a week until the effects were optimal. The outcome was evaluated retrospectively by comparing voiding/incontinence diaries obtained before and at the follow-up 6-12 months after the end of treatment.

RESULTS

AGAS was applied at the clinic for a median (range) of 9 (4-20) times. Thirty-one children continued with home stimulation for another 25 (5-96) sessions. At the follow-up, 18 children were cured and another seven improved, with a leakage score of less than half that before treatment. The treatment was well tolerated by most children.

CONCLUSIONS

Anogenital afferent stimulation is an effective, potentially curative treatment in children with severe urge incontinence. Home stimulation is a well accepted adjuvant to treatment at the clinic and improves the outcome.

Involvement of 5-hydroxytryptamine1A receptors in the modulation of micturition reflexes in the anesthetized rat

Intravenous administration of the selective 5-hydroxytryptamine (5-HT)1A receptor agonist 8-hydroxy-2-(di-N-propylaminotetralin (8-OH-DPAT) and of a low doses of buspirone elicited the supraspinal micturition reflex (SMR) in urethane-anesthetized rats when the urinary bladder was filled with just a subthreshold volume of saline (threshold conditions). The effect of i.v. 8-OH-DPAT was abolished by hexamethonium or spiroxatrine. When SMR was elicited by bladder distension (suprathreshold conditions), i.v. 8-OH-DPAT increased the frequency of bladder contractions. In threshold conditions, stimulation of SMR was also induced by i.c.v. or by i.t. administration of 8-OH-DPAT and 5-HT but not by topical application of 8-OH-DPAT onto the bladder. Guanethidine pretreatment, which produced detrusor hyperreflexia, antagonized the effect of both i.c.v. and i.t. 8-OH-DPAT. In rats treated with capsaicin as adults, the response to 8-OH-DPAT was unchanged. In rats treated with capsaicin as newborns, instead, the response to i.t. 8-OH-DPAT was abolished and that to i.c.v. 8-OH-DPAT was shifted to higher doses. Pretreatment with 5,7-dihyroxytryptamine did not affect the response to i.t. 8-OH-DPAT but shifted to higher doses the response to i.c.v. 8-OH-DPAT. Intravenous administration of spiroxatrine, methysergide, NAN-190 [1-(2-methoxyphenyl)-4-[4-(2-phtalimido)butyl] piperazine] or high doses of buspirone but not of 1-sulpiride inhibited SMR in suprathreshold conditions. The inhibitory effect of spiroxatrine, NAN-190 and buspirone was not reduced by guanethidine pretreatment. In chronically spinalized animals, i.v. 8-OH-DPAT increased the amplitude of the reflex bladder contractions induced by bladder distension.(ABSTRACT TRUNCATED AT 250 WORDS)