Medications used to treat bladder disorders may alter effects of neuromodulation.

AIMS: Neuromodulation (nerve stimulation) can produce analgesia. One form, bilateral pudendal nerve stimulation (bPNS), suppresses responses to urinary bladder distension (UBD) in hypersensitive rats. Drugs can modify this effect (eg, benzodiazepines, but not opioids, suppress bPNS effects). Prior to a clinical trial of bPNS effects on bladder pain, we felt it was prudent to survey the effects of medications commonly used in patients with bladder disorders. METHODS: Bladder hypersensitivity was produced by neonatal bladder inflammation in rat pups coupled with a second inflammatory insult as an adult. Antimuscarinic (oxybutynin), ß3 -adrenoceptor agonist (mirabegron, CL316243), α1 -adrenoceptor antagonist (tamsulosin), antidepressant (amitriptyline), muscle relaxing (baclofen), and sedative (propofol) agents were administered and effects of bPNS on responses to UBD assessed. bPNS consisted of bilateral biphasic electrical stimulation of the mixed motor/sensory component of the pudendal nerves. Visceromotor responses (VMRs; abdominal muscle contractile responses) were used as nociceptive endpoints. RESULTS: Many of these drugs directly inhibited the VMRs to UBD, but only mirabegron, at the doses employed, significantly reduced inhibitory effects of bPNS. In the presence of the other drugs, bPNS continued to produce statistically significant inhibition of VMRs to UBD. CONCLUSIONS: This study suggests that concurrent therapy with drugs used to treat bladder disorders could affect assessment of the effects of bPNS on bladder hypersensitivity. This study gives guidance to clinical trials using bPNS for the treatment of painful bladder syndromes and suggests potential clinical use of some of these medications in the treatment of these same disorders.

Periprostatic nerve block alone versus combined with perineal pudendal nerve block or intrarectal local anesthesia during transrectal ultrasound-guided prostate biopsy: A prospective randomized controlled trial.

OBJECTIVES: To compare the efficacy, safety and cost of combinations of perineal pudendal nerve block + periprostatic nerve block and intrarectal local anesthesia + periprostatic nerve block with the standard technique (periprostatic nerve block). METHODS: The study was designed as a randomized prospective controlled trial. Patients with elevated serum prostate-specific antigen values (prostate-specific antigen ≥4 ng/mL) and/or abnormal digital rectal examination findings were included in the study. Patients with anorectal diseases, chronic prostatitis, previous history of prostate biopsy and anorectal surgery were excluded from the study. A total of 148 patients (group 1 [periprostatic nerve block], n = 48; group 2 [intrarectal local anesthesia + periprostatic nerve block], n = 51; group 3 [perineal pudendal nerve block + periprostatic nerve block], n = 49) were included in the final analysis. Pain during insertion and manipulation of the transrectal ultrasound probe was recorded as visual analog scale 1, pain during penetration of the biopsy needle into the prostate and sampling was recorded as visual analog scale 2, and pain during the entire procedure recorded as visual analog scale 3. RESULTS: The mean visual analog scale 1 score was significantly lower in group 3, when compared with group 1 and group 2 (P < 0.001). There was no significant difference between the groups in terms of the mean visual analog scale 2 score. The mean visual analog scale 3 score was significantly lower in group 3 when compared with other groups (P < 0.001). The total cost for transrectal ultrasound-guided biopsy in the intrarectal local anesthesia + periprostatic nerve block group was significantly higher than the other two groups. CONCLUSIONS: The combination of perineal pudendal nerve block and periprostatic nerve block provides more effective pain control than intrarectal local anesthesia plus periprostatic nerve block and periprostatic nerve block alone, with similar complication rates and without increasing cost.

Dorsal Penile Nerve Block via Perineal Approach, an Alternative to a Caudal Block for Pediatric Circumcision: A Randomized Controlled Trial.

BACKGROUND: General anesthesia combining with a caudal block (CB) has been commonly performed in pediatric patients undergoing circumcision surgeries. However, some severe complications have been suspected of a caudal block in the combined use. To avoid these issues of a caudal block, this study introduces a novel dorsal penile nerve block (DPNB) via perineum guided by ultrasound as an alternative to a caudal block in pediatric circumcision surgeries. METHODS: A total of 104 pediatric patients scheduled for circumcision surgeries were involved and randomly divided into 2 groups: the CB group (n=52) and the DPNB group (n=52). A laryngeal mask was inserted followed by induction and maintenance anesthesia of inhaled sevoflurane. In the DPNB group, a dorsal penile nerve block (DPNB) guided by a real-time ultrasonography was performed by a single injection via perineum of 0.25% ropivacaine plus 0.8% lidocaine with total injection volume of 3-5ml. In the CB group, a dose of 0.5 ml/kg was given via the caudal canal following the same general anesthesia with that of Group DPNB. The time to the first analgesic demand after surgery is the key data collected for comparing between the two study groups. Heart rates and respiratory rates changes before and during the surgical procedure, pain score when leaving the PACU, and the time taken for the first micturition after a surgery were also recorded to analyze the differences in analgesic effects between the CB and DPNB groups. RESULTS: No significant difference in heart rates and respiratory rates was found between the two groups before and during the surgery. Pain scores were similar before pediatric patients leave the PACU. However, the time taken for the first micturition after a surgery in Group DPNB is shorter than Group CB. The patients in Group DPNB asked for analgesics later than those in Group CB. Additionally, no significant differences in adverse effects were noted between two groups except the numbness of the lower limbs occurring less in Group DPNB. CONCLUSIONS: The ultrasound-guided dorsal penile nerve block via perineal approach can basically act as a safe and effective alternative to the caudal block in pediatric patients undergoing circumcision surgeries. Clinical Trials identifier is ChiCTR-IPR-15006670. Protocol is available at http://www.chictr.org.cn/showproj.aspx?proj=11319.

Dorsal penile nerve block for circumcision in pediatric patients: A prospective, observer-blinded, randomized controlled clinical trial for the comparison of ultrasound-guided vs landmark technique.

BACKGROUND AND AIMS: Circumcision is a frequently performed procedure in day case pediatric surgery. Dorsal penile nerve block has proven its effectiveness for the management of acute postoperative pain after circumcision. We investigated if the ultrasound-guided placement of a dorsal penile nerve block could reduce opioid requirement as compared to a landmark-based technique. METHODS: Three hundred and ten prepubertal children, aged between 52 weeks postconception and 11 years, were included in this prospective, observer-blinded, randomized controlled trial and received either a landmark- or an ultrasound-guided dorsal penile nerve block, using a caudal needle and injecting 0.1 mL/kg levobupivacaine 0.5% bilaterally. A single, experienced investigator performed all blocks. The primary endpoint was the number of patients in need of piritramide postoperatively as triggered by the Objective Pain Scale. Secondary outcome parameters included the cumulative dose of postoperatively administered opioids, the requirement to administer fentanyl intraoperatively, the need for paracetamol and ibuprofen during the first 24 postoperative hours, postoperative pain scores, the incidence of postoperative nausea and vomiting, the anesthesia induction time, and the time to discharge. RESULTS: The proportion of patients requiring postoperative piritramide did not differ significantly between both groups (Landmark: 38% vs Ultrasound: 47%, with a difference in proportion between both conditions (95% CI): 0.09 (0.2 to 0.02); P = .135). In addition, the cumulative doses of postoperative piritramide and intraoperative fentanyl, the postoperative need for paracetamol or ibuprofen, pain scores, the incidence of postoperative nausea and vomiting, and the time to discharge were not different either. However, the anesthesia induction time was significantly longer in the ultrasound-guided dorsal penile nerve block (median time [IQR]: Landmark: 11[9; 13] min vs Ultrasound: 13[11; 15] min, P < .001). CONCLUSION: Compared with the landmark-guided, the ultrasound-guided dorsal penile nerve block did not reduce the need for postoperative analgesia after circumcision in children, but was associated with an increase in the procedural time.

Transient Methemoglobinemia in three Neonates due to Maternal Pudendal Anesthesia.

Methemoglobin (MetHb) is a form of hemoglobin which contains iron in ferric state. The delivery of oxygen to tissues is impaired and cellular hypoxia develops with an increase in MetHb levels. Methemoglobinemia is a rare but potentially lethal complication of local anesthetics. In this clinical brief, three cases of transient neonatal methemoglobinemia, caused by maternal pudendal anesthesia with prilocaine, are reported.