Bilateral Pudendal Nerve Block Research Articles

PWE-389 Anal acoustic reflectometry is a test of the internal anal sphincter?

Introduction Conventional anal manometry (ARM) suggested that the internal anal sphincter (IAS) contributes 60–85% of anal resting pressure, the remaining 15–40% being attributable to the tonic contraction of the external anal sphincter (EAS) and anal cushions. Anal acoustic reflectometry (AAR) is a more specific and sensitive indicator of sphincter function than ARM. Our aim was to determine the relative contributions of the IAS and EAS to anal resting pressure by isolating the IAS for interrogation using a bilateral pudendal nerve block (bPNB). Method Prospective cohort study of patients with pudendal neuralgia undergoing bPNB. Blocks were trans-vaginal (Women) and trans-gluteal (Men). EAS electromyography (EMG) was performed before and 5 mins after bPNB to establish its success. Patients received AAR and manometry (maximum resting pressure MRP, maximum squeeze pressure MSP and incremental squeeze pressure ISP) before and 30 mins after bPNB. Variables were compared using a paired t-test for parametric data and Wilcoxon signed rank test or Mann-Whitney U test* for non-parametric data. Results 15 patients, 10 (67%) women, median age 59 (25–89) and median reduction in EMG motor unit potential activity of 45% (Range -25–48%). There was no difference in reduction of EMG activity between trans-vaginal and trans-gluteal bPNB approach (30.3 v 38.5% p = 0.762*). There was no significant change in any AAR parameter at rest. AAR squeeze opening pressure showed a significant reduction post bPNB (121 v 104 cmH 2 O p = 0.039). MSP and ISP showed a significant reduction post bPNB; MRP 75 v 71 cmH 2 O p = 0.5, MSP 154 v 118 cmH 2 O p = 0.02, ISP 79 v 47 cmH 2 O p = 0.02. Conclusion We found a significant reduction in all measurements of EAS function after bPNB. No change was found after a 45% median reduction in EAS activity in measurements of IAS function, suggesting that AAR is primarily an investigation of the IAS. Disclosure of interest None Declared.

Bloc du nerf pudendal en chirurgie périnéo-vulvaire : étude monocentrique prospective randomisée

ObjectivesEvaluation of pudendal nerve block on the quality of analgesia in perineal or vulvar surgery. Patients and methodsWe realised a monocentered, prospective and randomised study of all patients undergoing perineo-vulvar surgery. Two groups of patients were evaluated: general anaesthesia alone (GA group, 41 patients) and both general anaesthesia and bilateral nerve stimulator-guided pudendal nerve block (15mL of Ropivacaïne 5mg.mL−1+0,5μg.kg−1 of Clonidine) (PB group, 42 patients). Evaluation of pain was realised with per- and post-surgical prescription of hypnotics and antalgics was noted. The primary outcome measure was the Visual Analogic Scale (VAS) pain means scores in the first postoperative 24hours. ResultsThere was no difference in the VAS pain means scores in the first 24hours, but it seemed to have a decrease in VAS pain at 2hours in the PB group. Analgesic consumption during surgery was decreased in the same group. No complication of the pudendal block has been reported. Discussion and conclusionThe nerve stimulator-guided pudendal nerve block is a simple and useful method which can, when associated with general anesthesia, reduce per-operative antalgics consumption and a decrease in the immediate postoperative pain in perineal or vulvar surgery, without complication or lengthening operating time. Further studies are needed to confirm the effectiveness of this technique and evaluate the costs and potential complications.

On The Etiology of the Electric Activity of the External Anal and Urethral Sphincters

ABSTRACTIn a previous study, the external anal sphincter (EAS) in dogs, known to consist of skeletal muscle fibers, was proved to contain bundles of smooth muscle fibers in between as well. Objective: Cause of electric activity in the external anal and urethral sphincters is not known; the current study investigated this point. Material and Methods: Slices from external anal and urethral sphincters of 21 cadavers (12 male, 9 female). Eighth were fully and mat wide neonates, 13 were adults, were stained with hematoxylin and eosin, Masson's trichrome and succinic dehydrogenase, and examined microscopically. Eighteen healthy volunteers, electromyography activity of their external anal and urethral sphincters was recorded at rest, on coughing, after pudendal nerve block and after drotaverine administration, (a smooth muscle relaxant). Anal and urethral pressures were also measured. Results: Microscopic studies have shown that both external anal and urethral sphincters were formed of bundles of smooth muscle fibers present in between the skeletal muscle fibers. Bilateral pudendal nerve block did not abolish the external anal or the urethral sphincters electromyography activity at rest, or on coughing, and did not cause significant anal or urethral pressure changes (p > .05). Drotaverine administration lead to disappearance of the electromyography activity and significant decline of the anal and urethral pressures (p < .05). The results were reproducible when the tests were repeated in the same subject. Conclusion: Histologic examination revealed the presence of smooth muscle fibers, between the skeletal fibers of the external anal and urethral sphincters. Evidence suggests that the smooth muscle fibers are the source of the electric activity of the sphincters and might explain some physiologic phenomena such as the external anal contraction on rectal distension or on coughing.

Dyspareunia Treated By Bilateral Pudendal Nerve Block

In this report, we present a patient with refractory superficial dyspareunia of unclear etiology, who was successfully managed with a bilateral pudendal nerve block. Initial workup failed to identify an obvious source for the pain and first-line therapy for postmenopausal superficial dyspareunia was not effective. A bilateral pudendal nerve block alleviated the problem to three years followup. In this report, we review the current dyspareunia literature and propose a diagnostic algorithm.

Development and Clinical Application of Pudendal Nerve Block Using A Peripheral Nerve Locator for Reproductive Surgery in Horses

AimsTo develop, describe and evaluate clinical applicability of pudendal nerve block using a peripheral nerve locator.MethodsIn a pilot study, 6 ponies were used to determine the correlation between nerves serving the perineal region (namely pudendal, caudorectal and perineal nerves) and the muscle contractions observed when an electrolocation technique was used. After appropriate electrolocation a small volume of lidocaine/methylene blue solution was injected under general anaesthesia. The dye location relative to the specified nerves was examined after humane euthanasia followed by dissection of the relevant region. In a second experiment, 7 Thoroughbred horses were used to evaluate the appropriate volume of lidocaine solution for the nerve block. Lidocaine/methylene blue solution was injected after positive electrolocation immediately (5–40 min) after euthanasia. A stained segment of 2 cm or more of the nerve was deemed to be sufficient and was evaluated after dissection. Finally, evaluation of a bilateral pudendal nerve block was used to provide anaesthesia and analgesia in 10 clinical cases involving both mares and geldings.ResultsAnal twitch alone was associated with injection of the caudal rectal nerve, whereas combined twitch of the anus and perineum was required for reliable location and injection of the pudendal nerve. Injection was more accurate in standing rather than laterally recumbent horses. A volume of 10–20 ml bilaterally, reliably provided at least 60 min of clinical analgesia for perineal surgery. Procedures satisfactorily completed included; urethral extension and perineal body repair in mares and penile examination, removal of penile tumours and penile amputation in male patients.Conclusions and practical significancePudendal nerve block is a practical and effective alternative to epidural analgesia for selected standing surgical procedures of the reproductive tract in male and female horses.Ethical animal researchThe Cornell University Institutional Animal Care and Use Committee approved the project and informed client consent was obtained. Sources of funding: None. Competing interests: None.

Research in the pudendal nerve block anesthesia timing during second stage of labor

Objective To discuss the influence of pudendal nerve block anesthesia on pain degree and labor course when presentation at different positions during the second stage of labor,in order to find the better anesthesia timing and method to reduce pain,shorten labor,increase maternal comfort to a maximum extent and provide the best service for the maternal.Methods 200 cases of primiparas with fullterm and single-birth were selected and numbered randomly,patients with odd numbers were set to the observation group,patients with even numbers were set to the control group,100 cases in each group.In the observation group,when the presentation reached S+1,1％ lidocaine was used to perform pudendal nerve block anesthesia.In the control group,the pudendal nerve block anesthesia was performed before perineal incision.Results The pain intensity,time of the second labor stage,perineum damage degree between the two groups were statistically different.The observation group with Ⅱ-grade level,Ⅲ-grade level pain were 32 cases less than that of the control group.The perineum incision later crack number in the observation group was 24 cases less than that of the control group.The number of delivery within 1 hour in the second labor process in the observation group was 21 cases more than that in the control group.Conclusions Implementation of bilateral pudendal nerve block anesthesia in the second stage of labor when the presentation reaches S+1 can alleviate childbirth pain,shorten the second stage of labor,reduce the degree of perineal trauma. Key words: The second stage of labor; Bilateral pudendal nerve block anesthesia; Anesthesia timing; Pain; Perineal trauma

Pre-emptive analgesia by nerve stimulator guided pudendal nerve block for posterior colpoperineorrhaphy

To assess the effect of pre-emptive analgesia by bilateral nerve stimulator-guided pudendal nerve block (PNB) on pain intensity and consumption of analgesics following posterior colpoperineorrhaphy. Prospective randomized observer-blinded study. The study included 130 patients who were scheduled to undergo posterior colpoperineorrhaphy under general anesthesia (GA). They were invited to enroll in the study during the period from October 2009 to August 2011 at TAIBA Hospital in Kuwait. Patients were randomly allocated to two groups of 65 patients each: GA alone or GA combined with pre-emptive nerve stimulator-guided PNB with 10 mL of 0.25% bupivacaine in each side. The primary outcome measures were VAS pain scores and postoperative analgesic consumption. Postoperative average VAS pain scores, IM pethidine consumption and IV paracetamol consumption during the first 24 h; were highly significantly lower in the PNB group compared to the GA alone group. This technique was also associated with a significantly higher overall patient satisfaction compared to GA alone, without obvious side effects. Pre-emptive analgesia by bilateral nerve stimulator-guided PNB is a simple and useful technique that when combined with GA was found to substantially reduce postoperative pain and consumption of analgesics during the first 24 h postoperatively, and shorten the time to return to normal activities compared to GA alone for patients undergoing posterior colpoperineorrhaphy. The use of PNB was also associated with a high overall patient satisfaction. Thus, the results of the present study may recommend the use of nerve stimulator-guided PNB in posterior colpoperineorrhaphy patients.

Raquianestesia com morfina versus raquianestesia sem morfina associada a bloqueio do nervo pudendo: avaliação da analgesia e complicações em hemorroidectomias

INTRODUÇÃO: Recentemente, alguns autores têm relatado que o bloqueio do nervo pudendo com uso de ropivacaína proporciona boa analgesia pós-operatória. Assim, considerou-se de interesse a comparação de dois métodos anestésicos verificando a analgesia pós-operatória e as complicações. OBJETIVO: Comparar duas técnicas anestésicas (raquianestesia com morfina versus raquianestesia sem morfina associada com bloqueio do nervo pudendo) para hemorroidectomia quanto à analgesia pósoperatória e complicações. MATERIAIS E MÉTODOS: Foram estudados 40 pacientes provenientes do ambulatório de Coloproctologia do Hospital Regional de Mato Grosso do Sul no período de março a outubro de 2008. Todos os pacientes foram randomizados por sorteio imediatamente antes de se iniciar a intervenção cirúrgica e foram distribuídos em dois grupos: Grupo 1: 20 pacientes submetidos à raquianestesia com morfina com 0,15µg associado com bupivacaína hiperbárica 10mg; - Grupo 2: 20 pacientes submetidos à raquianestesia com bupivacaína pesada 10mg associado ao bloqueio do nervo pudendo bilateral com agulha para raquianestesia 27G utilizando ropivacaína 10mg/ml diluída em 10ml de água destilada. RESULTADOS: Avaliou-se 40 pacientes, sendo 21 do sexo feminino. A idade média foi de 52 anos, variando de 21 a 72 anos. Apenas no grupo 1 observou-se complicações, sendo a principal prurido, seguida de retenção urinária e cefaléia. Após 6 horas da cirurgia, a média do nível de dor foi 1,55 no grupo 1 e 1,4 no grupo 2. Após 12 horas da cirurgia as médias foram 1,75 e 0,15 nos grupos 1 e 2, respectivamente. CONCLUSÃO: A hemorroidectomia realizada com associação de raquianestesia sem morfina e bloqueio do nervo pudendo utilizando ropivacaína proporcionou melhor efeito analgésico no período de 12 horas após a cirurgia e não apresentou complicações nesta casuística, mostrando-se superior à raquianestesia com morfina.

Pudendal Block with Bupivacaine for Postoperative Pain Relief

Postoperative pain after hemorrhoidectomy is very intense, and the pain at the first postoperative defecation is very intense. Based on our pilot initial results that reflected reduced postoperative pain, we conducted a prospective, randomized, double-blind study to investigate whether the analgesia produced by bilateral pudendal nerve block using a nerve-stimulator could provide better postoperative pain relief compared with the routine technique in use in the Department of Anesthesia. After Ethical Committee approval and informed consent, 100 patients scheduled for hemorrhoidectomy were randomized into control (C) and study (P) groups with 50 patients each. Bilateral pudendal nerve block with 0.25 percent bupivacaine was performed with nerve-stimulator. Evaluated parameters were pain severity, duration of analgesia, demand analgesia, and possible technique-related complications. Data were evaluated 6, 12, 18, and 24 hours after surgery completion. The first defecation and patient satisfaction were recorded. Successful pudendal nerves stimulation was achieved in all patients in the study group. The pudendal nerve block group was found to have better postoperative pain relief, reduced need for analgesics, and patient satisfaction. Mean analgesic duration was 23.8 +/- 4.8 hours vs. 3.6 +/- 1 hours. All patients in the pudendal nerve block had spontaneous micturition vs. 48 patients in the control group. The pudendal analgesia was considered excellent by 44 patients and satisfactory by 6 male patients. The six male patients complained because of penile anesthesia. No anesthetic-related local or systemic complications were observed. In this controlled study, bilateral pudendal nerve block oriented by nerve stimulator provided excellent analgesia with low need for opioids, without local or systemic complications, and without urinary retention.

Voiding reflex in chronic spinal cord injured cats induced by stimulating and blocking pudendal nerves

To induce efficient voiding in chronic spinal cord injured (SCI) cats. Voiding reflexes induced by bladder distension or by electrical stimulation and block of pudendal nerves were investigated in chronic SCI cats under alpha-chloralose anesthesia. The voiding efficiency in chronic SCI cats induced by bladder distension was very poor compared to that in spinal intact cats (7.3 +/- 0.9% vs. 93.6 +/- 2.0%, P < 0.05). In chronic SCI cats continuous stimulation of the pudendal nerve on one side at 20 Hz induced large amplitude bladder contractions, but failed to induce voiding. However, continuous pudendal nerve stimulation (20 Hz) combined with high-frequency (10 kHz) distal blockade of the ipsilateral pudendal nerve elicited efficient (73.2 +/- 10.7%) voiding. Blocking the pudendal nerves bilaterally produced voiding efficiency (82.5 +/- 4.8%) comparable to the efficiency during voidings induced by bladder distension in spinal intact cats, indicating that the external urethral sphincter (EUS) contraction was caused not only by direct activation of the pudendal efferent fibers, but also by spinal reflex activation of the EUS through the contralateral pudendal nerve. The maximal bladder pressure and average flow rate induced by stimulation and bilateral pudendal nerve block in chronic SCI cats were also comparable to those in spinal intact cats. This study shows that after the spinal cord is chronically isolated from the pontine micturition center, bladder distension evokes a transient, inefficient voiding reflex, whereas stimulation of somatic afferent fibers evokes a strong, long duration, spinal bladder reflex that elicits efficient voiding when combined with blockade of somatic efferent fibers in the pudendal nerves.

Contribution of the pudendal nerve to sensation of the distal rectum

Anal and rectal sensory mechanisms and pudendal nerve function are important in the control of faecal continence. The contribution of the pudendal nerve to sensation of the distal rectum was investigated. Heat thresholds in the anal canal, distal and mid rectum were measured using a specially designed thermoprobe. Rectal sensory threshold volumes were measured using the balloon distension method. Needle electrodes were inserted into the external anal sphincter. Pudendal nerve block was performed through a perineal approach, and completeness assessed by loss of electromyographic activity. Heat and rectal volume thresholds were measured again following unilateral and bilateral pudendal nerve block. The technique was successful in four of six volunteers. Bilateral pudendal nerve block produced complete anaesthesia to heat in the anal canal (P = 0.029), but had no effect on heat thresholds in the distal or mid rectum. Rectal sensory threshold volumes were also unaffected by pudendal nerve anaesthesia. Anal canal sensation is subserved by the pudendal nerve, but this nerve is not essential to nociceptive sensory mechanisms in the distal or mid rectum. The transition between visceral control mechanisms in the lower rectum and somatic mechanisms in the anal canal may have functional importance in the initiation of defaecation and the maintenance of continence.

Retrograde ejaculation caused by incomplete paralysis of pelvic nerve

A case of retrograde ejaculation is reported. Initially, it was considered idiopathic, but various examinations revealed subclinical neurogenic bladder with hypotonic detrusor and normal external urethral sphincter. This was due to incomplete paralysis of the pelvic nerve and the normal activity of the pudendal nerve. Normal antegrade ejaculation was obtained by bilateral pudendal nerve block. Some cases of idiopathic retrograde ejaculation are ascribable to neurogenic bladder; and urodynamic examination is essential in the diagnosis of this disease.