[Sacral Neuromodulation for Fecal Incontinence and Constipation: Evidence, Programming and Long-term Management]. / Sakralnervmodulation in der Therapie der Stuhlinkontinenz und Obstipation: Evidenz, Programmierung und Langzeitmanagement.

BACKGROUND: Over the last two decades, sacral neuromodulation (SNM) has established its role in the treatment of functional pelvic organ-/pelvic floor disorders. Even though the mode of action is not fully understood, SNM has become the preferred surgical treatment of fecal incontinence. METHODS AND RESULTS: A literature search was carried out on programming sacral neuromodulation and long-term outcomes in treating fecal incontinence and constipation.Sacral neuromodulation was found to be successful in the long term. Over the years, the spectrum of indications has expanded, and now includes patients presenting with anal sphincter lesions. The use of SNM for low anterior resection syndrome (LARS) is currently under clinical investigation. Findings of SNM for constipation are less convincing. In several randomised crossover studies, no success was demonstrated, even though it is possible that subgroups may benefit from the treatment. Currently the application cannot be recommended in general.The pulse generator programming sets the electrode configuration, amplitude, pulse frequency and pulse width. Usually pulse frequency and pulse width follow a default setting (14 Hz, 210 s), while electrode configuration and stimulation amplitude are adjusted individually to the patient need and perception of stimulation.Despite low infection rates and few electrode-/pulse generator dysfunctions, up to 65% of patients require surgical reintervention during long term follow-up - in 50% of cases because of battery depletion, which is an expected event. At least one reprogramming is necessary in about 75% of the patients during the course of the treatment, mostly because of changes in effectiveness, but rarely because of pain. Regular follow-up visits appear to be advisable. CONCLUSION: Sacral neuromodulation can be considered to be a safe and effective long-term therapy of fecal incontinence. To optimise the therapeutic effect, a structured follow-up regime is advisable.

Activation of MrgprA3 and MrgprC11 on Bladder-Innervating Afferents Induces Peripheral and Central Hypersensitivity to Bladder Distension.

Understanding the sensory mechanisms innervating the bladder is paramount to developing efficacious treatments for chronic bladder hypersensitivity conditions. The contribution of Mas-gene-related G protein-coupled receptors (Mrgpr) to bladder signaling is currently unknown. Using male and female mice, we show with single-cell RT-PCR that subpopulations of DRG neurons innervating the mouse bladder express MrgprA3 (14%) and MrgprC11 (38%), either individually or in combination, with high levels of coexpression with Trpv1 (81%-89%). Calcium imaging studies demonstrated MrgprA3 and MrgprC11 agonists (chloroquine, BAM8-22, and neuropeptide FF) activated subpopulations of bladder-innervating DRG neurons, showing functional evidence of coexpression between MrgprA3, MrgprC11, and TRPV1. In ex vivo bladder-nerve preparations, chloroquine, BAM8-22, and neuropeptide FF all evoked mechanical hypersensitivity in subpopulations (20%-41%) of bladder afferents. These effects were absent in recordings from Mrgpr-clusterΔ-/- mice. In vitro whole-cell patch-clamp recordings showed that application of an MrgprA3/C11 agonist mixture induced neuronal hyperexcitability in 44% of bladder-innervating DRG neurons. Finally, in vivo instillation of an MrgprA3/C11 agonist mixture into the bladder of WT mice induced a significant activation of dorsal horn neurons within the lumbosacral spinal cord, as quantified by pERK immunoreactivity. This MrgprA3/C11 agonist-induced activation was particularly apparent within the superficial dorsal horn and the sacral parasympathetic nuclei of WT, but not Mrgpr-clusterΔ-/- mice. This study demonstrates, for the first time, functional expression of MrgprA3 and MrgprC11 in bladder afferents. Activation of these receptors triggers hypersensitivity to distension, a critically valuable factor for therapeutic target development.SIGNIFICANCE STATEMENT Determining how bladder afferents become sensitized is the first step in finding effective treatments for common urological disorders such as overactive bladder and interstitial cystitis/bladder pain syndrome. Here we show that two of the key receptors, MrgprA3 and MrgprC11, that mediate itch from the skin are also expressed on afferents innervating the bladder. Activation of these receptors results in sensitization of bladder afferents, resulting in sensory signals being sent into the spinal cord that prematurely indicate bladder fullness. Targeting bladder afferents expressing MrgprA3 or MrgprC11 and preventing their sensitization may provide a novel approach for treating overactive bladder and interstitial cystitis/bladder pain syndrome.

Sacral neuromodulation for the prevention of a permanent stoma in patients with severe defecation disorder following intersphincteric resection.

PURPOSE: Severe defecation disorder occurs frequently in coloanal anastomosis for low rectal cancer, and may affect quality of life. Sacral neuromodulation (SNM) has been reported to be successful after rectal resection, but there are no results for patients treated with intersphincteric resection (ISR). METHODS: A retrospective single-center study of SNM was performed for patient with defecation disorder following ISR. Pre- and post-treatment bowel frequencies, fecal incontinence episodes, and Wexner, LARS and FIQL scores were assessed to evaluate the efficacy. A good response was defined as ≥ 50% reduction of bowel frequency per day or fecal incontinence episodes per week. RESULTS: 10 patients (7 males, mean age 67.5 years) underwent SNM. All patients had severe fecal incontinence with a median Wexner score of 15 (13-20) and a median LARS score of 41 (36-41). The Wexner score improved after SNM, but not significantly (p = 0.06). LARS and FIQL scores significantly improved after SNM (p = 0.02, p = 0.01). At the end of follow-up, the good response rate was 40%. Three cases without a good response required creation of a permanent stoma. CONCLUSION: Seven out of 10 patients did not require a permanent colostomy after SNM. SNM should be considered before performing a permanent colostomy.

Sacral nerve stimulation ameliorates colonic barrier functions in a rodent model of colitis.

BACKGROUND: The mucosal barrier damage is recognized as one of the key factors in the pathogenesis of colitis. While sacral nerve stimulation (SNS) was reported to have therapeutic potential for colitis, its mechanisms of actions on colonic permeability remained largely unknown. METHODS: In this study, colitis was induced by intrarectal administration of TNBS in rats. Five days later, they were treated with SNS or sham-SNS for 10 days. The effects of SNS on colonic permeability were assessed by measuring the expression of tight-junction proteins involved in regulating permeability and the FITC-dextran test. The mechanism of actions of SNS was investigated by studying the function of the enteric nervous system (ENS) cells and analyzing the autonomic nervous system. KEY RESULTS: SNS decreased the disease activity index, microscopic and macroscopic scores, myeloperoxidase activity, and pro-inflammatory cytokines (TNF-α, IL-6). SNS increased the expression of Zonula Occludens-1, Occludin, Claudin-1, and Junctional adhesion molecule-A in the colon tissue. The FITC-dextran test showed that the colonic permeability was lower with SCS than sham-SNS. SNS increased ChAT, pancreatic polypeptide, and GDNF and reduced norepinephrine NGF, sub-P, and mast cell overactivation in the colon tissue. Concurrently, SNS increased acetylcholine in colon tissues and elevated vagal efferent activity. CONCLUSIONS & INFERENCES: SNS ameliorates colonic inflammation and enhances colonic barrier function with the proposed mechanisms involving the increase in parasympathetic activity and modulation of the activity of the ENS and immune system, including mast cells.

A novel method of sacral nerve stimulation for colonic inflammation.

BACKGROUND: Vagal nerve stimulation has been reported to treat inflammation with promising results. The aims of our study were to optimize sacral nerve stimulation (SNS) methodologies for colonic inflammation in a rodent model of colitis and to investigate autonomic and cytokine mechanisms. METHODS: Three major efforts were made in optimizing SNS: (a) to determine the best stimulation duration: SNS-0.5h daily, SNS-1h daily, and SNS-3h daily with the parameters set at 5 Hz, 10 seconds on, 90 seconds off; (b) to determine the best stimulation position: bilateral, bipolar, and unipolar stimulation; (c) to determine the best stimulation parameters: our 5 Hz intermittent stimulation vs 14 Hz-210 µs continuous stimulation. Inflammatory responses were assessed by the disease activity index (DAI), histological analyses, and the myeloperoxidase (MPO) activity. Levels of inflammatory cytokines, norepinephrine (NE), and pancreatic polypeptide (PP) in both plasma and colon tissues were assessed. KEY RESULTS: Both SNS-1h and SNS-3h significantly ameliorated intestinal inflammation; SNS-1h was superior to SNS-3h. Bipolar but not bilateral or unipolar stimulation improved the inflammation in colitis. SNS with 5 Hz intermittent stimulation but not the 14 Hz continuous SNS was better for treating colitis in rats. SNS with the optimized stimulation parameters increased vagal activity and decreased sympathetic activity. CONCLUSION & INFERENCES: Bipolar stimulation for 1 hour daily using intermittent 5 Hz parameters is most effective in improving colonic inflammation in TNBS-treated rats by inhibiting pro-inflammatory cytokines and increasing anti-inflammatory cytokines via the modulation of the autonomic function.

Sacral nerve stimulation with appropriate parameters improves constipation in rats by enhancing colon motility mediated via the autonomic-cholinergic mechanisms.

Although sacral nerve stimulation (SNS) has been applied for treating constipation, its parameters were adopted from SNS for fecal incontinence, its effects are limited, and mechanisms are largely unknown. We investigated the effects and mechanism of SNS with appropriate parameters on constipation in rats treated with loperamide. First, using rectal compliance as an outcome measure, an experiment was performed to derive effective SNS parameters. Then, a 7-day SNS was performed in rats with constipation induced by loperamide. Autonomic functions were assessed by spectral analysis of heart rate variability (HRV) derived from an electrocardiogram. Serum levels of pancreatic polypeptide (PP), norepinephrine (NE), and acetylcholine (ACh) in colon were assessed. 1) Acute SNS at 5 Hz, 100 µs was found effective in enhancing rectal compliance and accelerating distal colon transit (P < 0.05 vs. sham SNS). 2) The 7-day SNS normalized loperamide-induced constipation, assessed by the number, weight, and water content of fecal pellets, and accelerated the distal colon transit (29.4 ± 3.7 min with sham SNS vs. 16.4 ± 5.3 min with SNS but not gastric emptying or intestinal transit. 3) SNS significantly increased vagal activity (P = 0.035) and decreased sympathetic activity (P = 0.012), assessed by spectral analysis of HRV as well as by the serum PP. 4) SNS increased ACh in the colon tissue; atropine blocked the accelerative effect of SNS on distal colon transit. We concluded that SNS with appropriate parameters improves constipation induced by loperamide by accelerating distal colon motility, mediated via the autonomic-cholinergic function.NEW & NOTEWORTHY Although sacral nerve stimulation (SNS) has been applied for treating constipation, its parameters were adopted from SNS for fecal incontinence, effects are limited, and mechanisms are largely unknown. This paper shows that SNS with appropriate parameters improves constipation induced by loperamide by accelerating distal colon motility mediated via the autonomic-cholinergic function.

Outcomes of Sacral Nerve Stimulation for Treatment of Refractory Overactive Bladder Among Octogenarians.

OBJECTIVE: Sacral nerve stimulation (SNS) is an effective treatment for refractory overactive bladder (OAB). However, advanced age is often cited as a reason to avoid SNS in the elderly. This study evaluates the safety and efficacy of SNS for refractory OAB among our octogenarian population. METHODS: A retrospective review from a single institution was performed on all SNS lead placements from December 1998 to June 2017 for refractory OAB. Octogenarians were characterized as 80 years of age or older at the time of Stage I. Efficacy and safety were determined by the rate of progression to Stage II, subsequent need for multimodal therapy, and rate of surgical revision and explantation. All patients were followed for a minimum of 12 months. RESULTS: Of 374 patients in this study, 37 (9.9%) were octogenarians. There was no difference in gender, race, smoking history, or prior OAB treatment regimens between cohorts. The rate of progression to Stage II was 56.8% for octogenarians compared to 60.5% for nonoctogenarians (p = 0.66). The rate of surgical revision, explantation, and need for multimodal therapy did not differ between groups. Subgroup analysis of octogenarians did not reveal any significant differences between successful and nonsuccessful Stage I patients. CONCLUSIONS: The safety and efficacy of SNS was similar between cohorts. This result suggests that SNS is a safe and effective therapy that should be considered among the treatment options for refractory OAB in octogenarian patients. Further studies are needed to determine predictive factors of Stage I success in elderly patients.

Complications After Continuous Posterior Lumbar Plexus Blockade for Total Hip Arthroplasty: A Retrospective Cohort Study.

BACKGROUND AND OBJECTIVES: While benefits of regional anesthesia in total hip arthroplasty (THA) are well documented, data describing the incidence of complications related to the use of posterior lumbar plexus blockade for THA remain limited. Our primary aim was to evaluate the incidence of infectious, bleeding, and neurological complications related specifically to the use of continuous posterior lumbar plexus block for elective THA. METHODS: We reviewed the electronic medical records of all adult patients who underwent elective THA with continuous posterior lumbar plexus blockade between December 1, 2004, and April 30, 2015, using the Mayo Clinic Total Joint Registry. All complications were verified via manual chart review by 2 reviewers. Patient demographics, type of surgery, and complications were analyzed. RESULTS: A total of 9649 patients who underwent 11,395 THA procedures met the inclusion criteria. There were 8686 (76.2%) primary and 2709 (23.8%) revision THAs. There were no block-related infections (0.00%; 95% confidence interval [CI], 0.00%-0.03%) and only 1 block-related hematoma (0.01%; 95% CI, 0.00%-0.05%) in a patient with multiple risk factors for bleeding. There were 60 (0.53%; 95% CI, 0.40%-0.68%) perioperative nerve injuries. Forty-three were in the sciatic distribution (71.67%; incidence, 0.38%). Although there were no documented overt iatrogenic nerve injuries, the posterior lumbar plexus blockade could not be excluded as the potential cause in 9 cases (incidence, 0.08%) based on clinical distribution or electromyographic findings. CONCLUSIONS: In our large, single-center cohort study, we report no catheter-related infections, whereas catheter-related hemorrhagic and neurological complications also appear to be rare.

Sacral Neuromodulation for Genitourinary Problems.

Sacral neuromodulation (SNM) is a minimally invasive therapeutic option for many voiding dysfunction conditions. It is approved by the US FDA for refractory overactive bladder with and without incontinence and nonobstructive retention. Since SNM has shown a favorable response for these approved indications, other therapeutic applications have been proposed for various conditions such as painful bladder syndrome, chronic pelvic pain and neurological voiding dysfunction in both adult and pediatric age groups. SNM therapy with the most commonly used dedicated SNM device (InterStim) involves insertion of electrode(s) in the third and/or fourth sacral foramen next to the nerve root. The electrode is then connected to a battery-operated pulse generator. All patients need to have a test trial period before definitive device insertion. Here we discuss SNM therapy in functional urinary disorders and the technique of device insertion with the potential pitfalls.

Sacral Nerve Stimulation in the Treatment of Bowel Disorders.

Defecation problems occur in patients of all ages, but are more prevalent in the elderly, postpartum women, and patients with chronic and debilitating medical conditions. Most of the time, these problems respond to medical therapy and nonsurgical options, but it is not uncommon for patients to require surgical intervention. Sacral nerve stimulation (SNS) presents an alternative for patients with bowel dysfunction combining proven therapeutic benefits and limited surgical risks. Here we describe the common indications for SNS, patient selection, technical details of the procedure, published outcomes, and complications that can arise. Based on our review, SNS is an effective treatment option for fecal incontinence and may reduce the patients' clinical symptoms and help restore their quality of life. Future research studies may expand the role of this modality for other bowel disorders.

The Evolution and Technique of Nerve-Sparing Retroperitoneal Lymphadenectomy.

The evolution of retroperitoneal lymph node dissection technique and associated template modifications for nonseminomatous germ cell tumors have resulted in significant improvement in the long-term morbidity. Through the preservation of sympathetic nerves via exclusion from or prospective identification within the boundaries of resection, maintenance and recovery of antegrade ejaculation are achieved. Nerve-sparing strategies in early-stage disease are feasible in most patients. Postchemotherapy, select patients can be considered for nerve preservation. This article describes the anatomic and physiologic basis for, indications and technical aspects of, and functional and oncologic outcomes reported after nerve-sparing retroperitoneal lymphadenectomy in testicular cancer.

Somatomotor and sensory urethral control of micturition in female rats.

In rats, axons of external urethral sphincter (EUS) motoneurons travel through the anastomotic branch of the pudendal nerve (ABPD) and anastomotic branch of the lumbosacral trunk (ABLT) and converge in the motor branch of the sacral plexus (MBSP). The aim of the present study was to determine in female rats the contribution of these somatomotor pathways and urethral sensory innervation from the dorsal nerve of the clitoris on urinary continence and voiding. EUS electromyographic (EMG) activity during cystometry, leak point pressure (LPP), and voiding efficiency (VE) were assessed in anesthetized virgin Sprague-Dawley female rats before and after transection of the above nerve branches. Transection of the MBSP eliminated EUS EMG, decreased LPP by 50%, and significantly reduced bladder contraction duration, peak pressure, intercontraction interval, and VE. Transection of the ABPD or ABLT decreased EUS EMG discharge and LPP by 25% but did not affect VE. Transection of the dorsal nerve of the clitoris did not affect LPP but reduced contraction duration, peak pressure, intercontraction interval, and VE. We conclude that somatomotor control of micturition is provided by the MBSP with axons travelling through the ABPD and ABLT. Partial somatomotor urethral denervation induces mild urinary incontinence, whereas partial afferent denervation induces voiding dysfunction. ABPD and ABLT pathways could represent a safeguard ensuring innervation to the EUS in case of upper nerve damage. Detailed knowledge of neuroanatomy and functional innervation of the urethra will enable more accurate animal models of neural development, disease, and dysfunction in the future.

Effects of stimulation frequency and intensity in sacral neuromodulation on anorectal inputs to the somatosensory cortex in an experimental model.

INTRODUCTION: Although sacral neuromodulation (SNM) is an established treatment for faecal incontinence, stimulation parameters have been derived empirically and only one frequency (14 Hz) is employed clinically. The aim of this study was to test a range of stimulation frequencies to establish an optimal frequency of SNM for maximum augmentation of anal canal cortical evoked potentials (EPs) in an animal model. METHODS: In female Wistar rats, anal canal EPs were recorded over the primary somatosensory cortex using a flexible multielectrode array, and the effect of SNM was studied. SNM was applied at 0·1-100 Hz and a frequency response curve plotted. The data were fitted to a quadratic equation. RESULTS: The magnitude of potentiation of anal canal EPs caused by SNM depended significantly on stimulation frequency (P < 0·001). The frequency-potentiation relationship was parabolic in form, with a clear optimum at 2 Hz. The SNM must be applied for at least 3 min. The theoretical maximal potentiation predicted by the model was not found to be statistically different to actual data recorded (P = 0·514-0·814). The response depended on stimulation amplitude in an 'all-or-nothing' fashion. EPs were augmented when the SNM intensity was 0·5 times the motor threshold to tail twitch or greater, but values below this intensity failed to affect the EPs. CONCLUSION: The effect of SNM in this animal model is governed principally by frequency, with an optimum of 2 Hz. If animal data can be translated to humans, optimization of SNM frequency may offer a clinically relevant improvement in the efficacy of SNM. Surgical relevance Sacral neuromodulation (SNM) for faecal incontinence currently employs stimulation parameters that have been derived empirically and may not be optimal. This study used an animal model of SNM and focused on its acute effect on anal canal cortical evoked potentials (EPs). It was found that SNM potentiated EPs, with a clear optimum at a frequency of 2 Hz. If this finding is applicable to the mechanism of action of human SNM, this suggests that there may be a clinically relevant improvement by reducing stimulus frequency from its typical value of 14 Hz to 2 Hz.

Prospective clinical audit of two neuromodulatory treatments for fecal incontinence: sacral nerve stimulation (SNS) and percutaneous tibial nerve stimulation (PTNS).

BACKGROUND AND PURPOSE: Two types of neuromodulation are currently practised for the treatment of fecal incontinence (FI): sacral nerve stimulation (SNS) and percutaneous tibial nerve stimulation (PTNS). This study compares these therapies, as no data exist to prospectively assess their relative efficacy and costs. METHODS: The subjects of this study were two distinct cohorts undergoing SNS (between 2003 and 2008) or PTNS (2008-onwards) for FI. Clinical outcomes assessed at 3 months included incontinence scores and the number of weekly incontinence episodes. The direct medical costs for each procedure were calculated from the audited expenditure of our unit. RESULTS: Thirty-seven patients (94.6 % women) underwent permanent SNS and 146 (87.7 % women) underwent PTNS. The mean pre-treatment incontinence score (± SD) was greater in the SNS cohort (14 ± 4 vs. 12 ± 4) and the mean post-treatment incontinence scores were similar for the two therapies (9 ± 5 vs. 10 ± 4), with a greater effect size evident in the SNS patients. In a 'pseudo case-control' analysis with 37 "matched" patients, the effect of both treatments was similar. The cost of treating a patient for 1 year was £ 11,374 ($ 18,223) for permanent SNS vs. £ 1740 ($ 2784) for PTNS. CONCLUSION: Given the lesser cost and invasive nature of PTNS, where both techniques are available, a trial of PTNS could be considered for all patients.

Emerging surgical therapies for faecal incontinence.

Faecal incontinence is a common condition and is associated with considerable morbidity and economic cost. The majority of patients are managed with conservative interventions. However, for those patients with severe or refractory incontinence, surgical treatment might be required. Over the past 20 years, numerous developments have been made in the surgical therapies available to treat such patients. These surgical therapies can be classified as techniques of neuromodulation, neosphincter creation (muscle or artificial) and injection therapy. Techniques of neuromodulation, particularly sacral nerve stimulation, have transformed the management of these patients with a minimally invasive procedure that offers good results and low morbidity. By contrast, neosphincter procedures are characterized by being more invasive and associated with considerable morbidity, although some patients will experience substantial improvements in their continence. Injection of bulking agents into the anal canal can improve symptoms and quality of life in patients with mild-to-moderate incontinence, and the use of autologous myoblasts might be a future therapy. Further research and development is required not only in terms of the devices and procedures, but also to identify which patients are likely to benefit most from such interventions.

Recording sympathetic nerve activity chronically in rats: surgery techniques, assessment of nerve activity, and quantification.

The sympathetic nervous system plays a pivotal role in homeostasis through its direct innervation and functional impact on a variety of end organs. In rats, a number of methods are available to assess sympathetic nervous system function. Traditionally, direct recording of sympathetic nerve activity (SNA) has been restricted to acute, anesthetized preparations or conscious animals within a few days after electrode implantation. However, these approaches provide short-term data in studies designed to investigate changes in SNA during chronic disease states. Over the last several years, chronic SNA recording has been pioneered in rabbits and more recently in rats. The purpose of this article is to provide insights and a "how to" guide for chronic SNA recordings in rats based on experiences from two independent laboratories. We will present common methodologies used to chronically record SNA, characteristics and methods to distinguish sympathetic bursts versus electrical artifacts (and provide corresponding audio clips when available), and provide suggestions for analysis and presentation of data. In many instances, these same guidelines are applicable to acute SNA recordings. Using the surgical approaches described herein, both laboratories have been able to chronically record SNA in >50% of rats for a duration >3 wk. The ability to record SNA over the time course of several weeks will, undoubtedly, greatly impact the field of autonomic and cardiovascular physiology.

Differential effects of intravesical resiniferatoxin on excitability of bladder spinal neurons upon colon-bladder cross-sensitization.

Cross-sensitization in the pelvis may contribute to etiology of functional pelvic pain disorders such as interstitial cystitis/bladder pain syndrome (IC/BPS). Increasing evidence suggests the involvement of transient receptor potential vanilloid 1 (TRPV1) receptors in the development of neurogenic inflammation in the pelvis and pelvic organ cross-sensitization. The objective of this study was to test the hypothesis that desensitization of TRPV1 receptors in the urinary bladder can minimize the effects of cross-sensitization induced by experimental colitis on excitability of bladder spinal neurons. Extracellular activity of bladder neurons was recorded in response to graded urinary bladder distension (UBD) in rats pretreated with intravesical resiniferatoxin (RTX, 10(-7)M). Colonic inflammation was induced by intracolonic instillation of 2,4,6-trinitrobenzene sulfonic acid (TNBS). The duration of excitatory responses to noxious UBD during acute colonic inflammation (3 days post-TNBS) was significantly shortened in the group with RTX pretreatment (25.3±1.5s, n=49) when compared to the control group (35.1±4.2s, n=43, p<0.05). The duration of long-lasting excitatory responses, but not short-lasting responses of bladder spinal neurons during acute colitis was significantly reduced by RTX from 52.9±6.6s (n=21, vehicle group) to 34.4±2.1s (RTX group, n=21, p<0.05). However, activation of TRPV1 receptors in the urinary bladder prior to acute colitis increased the number of bladder neurons receiving input from large somatic fields from 22.7% to 58.2% (p<0.01). The results of our study provide evidence that intravesical RTX reduces the effects of viscerovisceral cross-talk induced by colonic inflammation on bladder spinal neurons. However, RTX enhances the responses of bladder neurons to somatic stimulation, thereby limiting its therapeutic potential.

Lumbar plexus blockade reduces pain after hip arthroscopy: a prospective randomized controlled trial.

BACKGROUND: Hip arthroscopy causes moderate to severe postoperative pain. We hypothesized that performance of a lumbar plexus block (LPB) would reduce postoperative pain in the postanesthesia care unit (PACU) for patients discharged home on the day of surgery. METHODS: Patients received a combined spinal epidural with IV sedation, ondansetron, and ketorolac. Half of the patients (n = 42) also underwent a single-injection bupivacaine LPB. Postoperative analgesia (PACU and after discharge) was provided with oral hydrocodone/acetaminophen (5/500 mg) and an oral nonsteroidal antiinflammatory drug. IV hydromorphone was given as needed in the PACU. RESULTS: The LPB reduced pain at rest in the PACU (GEE: ß estimate of the mean on a 0 to 10 scale = -0.9; 95% confidence interval = -1.7 to -0.1; P = 0.037). Mean PACU pain scores at rest were reduced by the LPB from 4.2 to 3.3 (P = 0.048, 95% confidence interval for difference = 0.007-1.8; uncorrected for multiple values per patient, using independent samples t test for preliminary evaluation comparing pain between the groups). There were no statistically significant differences in PACU analgesic usage, PACU pain with movement, and patient satisfaction. No permanent adverse events occurred, but 2 LPB patients fell in the PACU bathroom, without injury. Three unplanned admissions occurred; one LPB patient was admitted for epidural spread and urinary retention. Two control patients were admitted, one for oxygen desaturation and one for pain and nausea. CONCLUSION: LPB resulted in statistically significant reductions in PACU resting pain after hip arthroscopy, but the absence of improvement in most secondary outcomes suggests that assessment of risks and benefits of LPB should be individualized.