Key Anatomical Concepts, Landmarks, and Proposed Terminology for Nerve-Sparing Gynecologic Surgery: A Narrative Review.

OBJECTIVE: To synthesize the terminology utilized in nerve-sparing surgical literature and propose standardized and nonconflicting terms to allow for consistent vocabulary. DESIGN: We performed a literature search on PubMed using the search terms "pelvis" and "nerve-sparing." Nongynecologic surgery and animal studies were excluded. A narrative review was performed, focusing on nerves, fasciae, ligaments, and retroperitoneal spaces. Terms from included papers were discussed by all authors, who are surgeons versed in nerve-sparing procedures and one anatomist, and recommendations were made regarding the most appropriate terms based on the frequency of occurrence in the literature and the possibility of overlapping names with other structures. RESULTS: 224 articles were identified, with 81 included in the full-text review. Overall, 48% of articles focused on cervical cancer and 26% on deeply infiltrating endometriosis. Findings were synthesized both narratively and visually. Inconsistencies in pelvic anatomical nomenclature were prevalent across publications. The structure with the most varied terminology was the rectal branch of the inferior hypogastric plexus with 14 names. A standardized terminology for pelvic autonomic nerve structures, fasciae, ligaments, and retroperitoneal spaces was proposed to avoid conflicting terms. CONCLUSION: Surgeons and anatomists should use consistent terminology to facilitate increased uptake of nerve-sparing techniques in gynecologic surgery through a better understanding of surgical technique description. We have proposed a standardized terminology believed to facilitate this goal.

The implications of the anatomy of the nerves and vessels in the treatment of rectosigmoid endometriosis.

Endometriosis is a common benign gynecological disease characterized by the presence of endometrial glands and stroma outside the uterus. It can be defined as endometrioma, superficial peritoneal endometriosis or deep infiltrating endometriosis (DIE) depending on the location and the depth of infiltration of the organs. In 5%-12% of cases, DIE affects the digestive tract, frequently involving the distal part of the sigmoid colon and rectum. Surgery is generally recommended in cases of obstructive symptoms and in cases with pain that is non-responsive to medical treatment. Selection of the most optimal surgical technique for the treatment of bowel endometriosis must consider different variables, including the number of lesions, eventual multifocal lesions, as well as length, width and grade of infiltration into the bowel wall. Except for some major and widely accepted indications regarding bowel resection, established international guidelines are not clear on when to employ a more conservative approach like rectal shaving or discoid resection, and when, instead, to opt for bowel resection. Damage to the pelvic autonomic nervous system may be avoided by detection of the middle rectal artery, where its relationship with female pelvic nerve fibers allows its use as an anatomical landmark. To reduce the risk of potential vascular and nervous complications related to bowel resection, a less invasive approach such as shaving or discoid resection can be considered as potential treatment options. Additionally, the middle rectal artery can be used as a reference point in cases of upper bowel resection, where a trans mesorectal technique should be preferred to prevent devascularization and denervation of the bowel segments not affected by the disease.

Applied anatomy of female pelvic plexus for nerve-sparing radical hysterectomy(NSRH).

BACKGROUND: Nerve-sparing radical hysterectomy(NSRH)has the advantage of reducing postoperative complications and improving postoperative quality of life. The separation and protection of the pelvic plexus in NSRH is extremely important and challenging. METHODS: 24 female cadaveric hemipelves were dissected. Morphologic patterns and compositions of pelvic plexus as well as relationship of pelvic plexus to the surrounding structures were observed and documented. RESULTS: Two patterns of superior hypogastric plexus were observed, including fenestrated and cord-like shape. The origin of bilateral hypogastric nerves were inferiorly to upper margin of promontory about 1.6 ± 0.1 cm and parallel to the ureter in front of the sacrum. Pelvic splanchnic nerves(PSN)from the second sacral nerve, the third sacral nerve and the forth sacral nerve were observed combing with the hypogastric nerves within the lateral rectal ligament. The sacral sympathetic trunk can be identified anteriorly or medially to the anterior sacral foramen. We identified the boundaries of pelvic plexus as following: the upper margin is formed by the PSNs from the third sacral nerve, posterior margin by inferior rectal artery, and anteriorly by vesical venous plexus. The uterine branches from pelvic plexus were observed accompanying with uterine artery, while other branches were inferiorly to the artery. The PSNs were located beneath the deep uterine veins within the cardinal ligament. The upper margin of pelvic plexus was observed directly approach to urinary bladder within the vesico-vaginal ligament as a single trunk accompanying with ureter, between the middle and inferior vesical veins. CONCLUSIONS: Our study clarified the intricate arrangement, distribution and relationship of female pelvic plexus and the related structures to provide reference index for NSRH application. The innervation patterns of bladder and uterine were clarified, and by tracing these visceral branches of pelvic plexus, we suggest several new important land markers for NSRH.

Anatomical location of the surgically identifiable bladder branch of the inferior hypogastric plexus for nerve-sparing radical hysterectomy.

Objective: We aimed to demonstrate the entire structure of the inferior hypogastric plexus in the female pelvis focusing on surgically identifiable nerve bundles to the urinary bladder. Methods: Surgical videos of transabdominal nerve-sparing radical hysterectomy for 10 patients with cervical cancer at International Federation of Gynecology and Obstetrics (FIGO 2009) stage IB1-IIB were retrospectively analyzed. The paracervical tissue dorsal to the ureter was separated into the lateral component (dorsal layer of the vesicouterine ligament) and medial component (paracolpium) using Okabayashi's technique. Any bundle-like structures in the paracervical area were isolated and divided using cold scissors, and each cut edge was inspected to determine whether the bundle was a blood vessel or a nerve. Results: In all cases, the surgically identifiable nerve bundle of the bladder branch was identified on the rectovaginal ligament running parallel and dorsal to the vaginal vein of the paracolpium. The bladder branch was revealed only after complete division of the vesical veins in the dorsal layer of the vesicouterine ligament where no definitive nerve bundles were observed. The bladder branch was derived laterally from the pelvic splanchnic nerve and medially from the inferior hypogastric plexus. Conclusions: The surgical identification of the nerve bundle of the bladder branch is essential for a safe and secure nerve-sparing radical hysterectomy. The preservation of the surgically identifiable bladder branch from the pelvic splanchnic nerve as well as from the inferior hypogastric plexus can provide satisfactory postoperative voiding function.

Simplified approach to the medial internal iliac region using a uretero-hypogastric nerve fascia development procedure for extended pelvic lymph node dissection during robot-assisted radical prostatectomy for high-risk prostate cancer.

INTRODUCTION: Although several clinical guidelines for prostate cancer (PC) recommend extended pelvic lymph node dissection (ePLND) during radical prostatectomy for high-risk cases, there are several issues to consider, including certain technical aspects. A simplified approach to the medial internal iliac region and paravesical arteries has not been established. The uretero-hypogastric nerve fascia (UHF) envelopes the ureter, hypogastric nerve, and pelvic autonomic nerves. To preserve the UHF, it is possible to approach the medial side of the internal iliac vessels without injuring any important tissue. We analyzed technical feasibility and lymph node (LN) yields. PATIENTS AND METHODS: After obtaining institutional review board approval, 265 high-risk PC patients with ePLND were identified. A da Vinci S or Xi robotic surgical system (Intuitive Surgical, Sunnyvale, CA, USA) was used. We divided the patients into conventional (non-UHF) method and modified (UHF) groups. The numbers of LNs removed, procedure-related complications, and surgical outcomes were analyzed. RESULTS: The median number of LNs removed was 19.0 in the non-UHF group and 22.0 in the UHF group (p = 0.004). Significantly more LNs were removed from the internal iliac region in the UHF group (p = 0.042). There was no difference in overall operative, console, or LN dissection time, or the severe complication rate (Clavien-Dindo grade ≥ III), between the non-UHF and UHF groups. CONCLUSIONS: Our simplified approach using the UHF development technique is technically feasible, has no major complications, and allows for the removal of significantly more LNs compared with the conventional method.

Superior Hypogastric Plexus Nerve Block in Minimally Invasive Gynecology: A Randomized Controlled Trial.

STUDY OBJECTIVE: To assess the efficacy of a superior hypogastric plexus nerve block in reducing opioid requirements in the first 24 hours after minimally invasive gynecologic surgery. DESIGN: Patient-blinded randomized controlled trial. SETTING: Single-center academic institution (Sydney Women's Endosurgery Centre). Two surgeons administering the blocks in their own surgeries. PATIENTS: Patients undergoing either laparoscopic or robot-assisted laparoscopic hysterectomy or myomectomy for benign indications. INTERVENTIONS: Ropivacaine 10 mL (0.75%) infiltrated into the retroperitoneal space overlying the superior hypogastric plexus vs control of no block given at the completion of surgery. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the total opioid use in the first 24 hours after surgery, measured in morphine milligram equivalents (MME). Standardized fentanyl patient-controlled analgesia was given to all patients in the trial. The secondary outcome was pain measured on a visual analog scale (1 to 10) at 1, 2, 6, 12, and 24 hours after surgery. Fifty patients out of 56 approached for the study participated in, and completed, the study (89.2%). The patients were randomized over a 5-month period, March 2020 to July 2020. A total of 27 patients were randomized to receive a nerve block, and 23 were randomized to the control. There was a difference of -21.8 MME in the block group compared with the no-block group (95% confidence interval [CI], -38.2 to -5.5; p = .008). This correlated to a 38% reduction in opioid use in the block group. The mean opioid use in the patients in the block group was 33.1 MME (95% CI, 24.2-41.9) and in those in the no-block group 54.9 MME (95% CI, 40.7-69.1). For the block group, opioid use ranged from 1.0 to 76.5 MME, with an interquartile range of 37 (14-51). For the control group, the range was 7.5 to 113.5 MME, with a higher interquartile range of 60 (28-88). Pairwise comparisons of the mean pain scores over the 24 hours showed a lower pain score with a nerve block of 1.8 (95% CI, 1.5-2.1) compared with a no-block score of 2.6 (95% CI, 2.3-2.9) No adverse effects of local anesthetic toxicity, nerve injury, or bowel/vascular injury were noted in any patient. CONCLUSION: A superior hypogastric plexus nerve block is a simple technique for reducing postoperative opioid requirements and pain in the first 24 hours after minimally invasive gynecologic surgery.

Standard practice of presacral exposure during transvaginal natural orifice transluminal endoscopic surgery for sacrocolpopexy.

We describe the standard practice of presacral exposure during transvaginal natural orifice transluminal endoscopic surgery (vNOTES) for sacrocolpopexy in women with uterine prolapse. In this video, we demonstrate the key techniques: identifying the right hypogastric nerve (rHN) before opening the pelvic peritoneum; removing the fat and loose connective tissue along the rHN to expose the presacral fascia; incising the presacral fascia to reach the presacral space to expose the middle sacral vasculature and the anterior longitudinal ligament (ALL) of the first sacral vertebra (S1) below the promontory; attaching the mesh to the ALL to avoid vessel injury; and completing the peritonealisation.

Ultrasound of the Uterosacral Ligament, Parametrium, and Paracervix: Disagreement in Terminology between Imaging Anatomy and Modern Gynecologic Surgery.

Ultrasound is an effective tool to detect and characterize lesions of the uterosacral ligament, parametrium, and paracervix. They may be the site of diseases such as endometriosis and the later stages of cervical cancer. Endometriosis and advanced stages of cervical cancer may infiltrate the parametrium and may also involve the ureter, resulting in a more complex surgery. New functional, surgical anatomy requires the complete diagnostic description of retroperitoneal spaces and tissues that contain vessels and nerves. Most endometriosis lesions and cervical cancer spread involve the cervical section of the uterosacral ligament, which is close to tissues, namely the parametrium and paracervix, which contain vessels and important nerves and nerve anastomoses of the inferior hypogastric plexus. Efferent fibers of the plexus travel to the rectum, uterus, rectovaginal ligament, deep vesicouterine ligament, and bladder. These efferent fibers are essential for bladder and rectal functionality so tailored nerve-sparing surgery became a standard approach for treating deep infiltrating endometriosis and cervical cancer. An accurate diagnosis by ultrasound has significant clinical impact and is important for appropriate treatment. In this article, we try to establish a common terminology between imaging diagnostic and modern surgical anatomy.

Vaginal-assisted laparoscopic nerve sparing radical trachelectomy

Fertility-sparing surgery has gained popularity in the last three decades for the management of cervical cancer in women under 40 years of age. Radical trachelectomy is a fertility-sparing surgical technique for women who wish to retain their fertility. Vaginal-assisted laparoscopic radical trachelectomy is feasible in selected patients with early cervical cancer. The aim of this video is to present a nerve-sparing vaginal-assisted laparoscopic radical trachelectomy demonstrating pelvic anatomical structures.

Nerve-Sparing Radical Hysterectomy: Kobayashi's Method.

After Prof. S. Okabayashi introduced Okabayashi Operation in 1921, several surgeons introduced numerous improvements in Japan. One of them is so-called the Tokyo Method which was improved and revised by Dr. Kyusaku Ogino (1950), Prof. Takashi Kobayashi, University of Tokyo (1961, 1970), and Prof. Shoichi Sakamoto, University of Tokyo (1981). The nerve-sparing radical hysterectomy without sacrificing radicality was introduced in 1961 1 and improved in 1970 by Prof. Kobayashi. 2 The autonomic nerve pathway including hypogastric nerve (sympathetic nerve), pelvic splanchnic nerve (parasympathetic nerve), and pelvic nerve plexus as a junction of the two nerves and the branch of the plexus to the bladder (vesical nerve branch) are preserved except in advanced cases. He divided the process of nerve-sparing surgery into four steps for separating the autonomic nerve pathway from adjacent tissues along the pathway consisting of cardinal, sacrouterine, rectouterine/vaginal, and vesicouterine ligaments. The first step is separation of the cardinal ligament (deep uterine vessels) from the pelvic splanchnic nerve. The second step is separation of the medial side of severed cardinal ligament from the pelvic nerve plexus. The first and second steps are performed in the lateral side of the autonomic nerve system. The third step is separation of sacrouterine and rectouterine/vaginal ligaments from hypogastric nerve and pelvic nerve plexus. The third step is necessary for achieving high radicality, namely, for severing the sacrouterine and rectouterine/vaginal ligaments near the rectum without damage to the pelvic nerve plexus. The fourth step is separation of paravaginal tissues and posterior (deep) layer of the vesicouterine ligament from the vesical nerve branches of the plexus. The third and fourth steps are performed in the medial side of the autonomic nerve system.

Efficacy of fluoroscopy-guided superior hypogastric nerve block on pain degree after uterine artery embolization / 中华放射学杂志

Objective:To investigate the clinical efficacy of superior hypogastric nerve block (SHNB) in relieving pelvic pain after uterine artery embolization (UAE).Methods:Totally 50 patients of UAE before the curettage of uterine incision pregnancy were selected in Affiliated Zhenjiang Fourth People′s Hospital,Jiangsu University from February 2019 to December 2020 and were randomly divided into SHNB group( n=22) and control group( n=28) using random number table. The SHNB group underwent fluoroscopy-guided SHNB before UAE, and the control group received dizocine 10 mg intramuscularly before embolization. Both groups were treated with curettage 24 h after UAE. The pain scores were evaluated by using a numerical rating scale (NRS) to compare the pain scores between the two groups atthe time period A1 (from the beginning of UAE to immediate postoperative period) and at the time period A2 (from leaving the interventional operating room to the time before curettage). Data was recorded and compared between the two groups at the time period from the beginning of UAE surgery to the time before curettage for the doses of opioids used.The differences inage and weight between the two groups were compared by independent sample t test, and the NRS score and morphine dose were compared by Mann-whitney U test. Results:All patients completed SHNB and UAE without serious complications.There was no significant difference in age and weight between the two groups ( P>0.05).The maximum pain scores in the SHNB group were lower than those in the control group at both the A1 and A2 time periods[0(0, 0.25) vs. 3.00 (2.00, 4.00), and 2.50 (0.75, 5.50) vs. 4.00 (3.25, 7.00); Z=-4.932, -2.351, P<0.05]. The equivalent dose of morphine required in the SHNB group was lower than that of the control group [0(0, 10.00) vs. 10.00 (5.00, 15.00)mg, Z=-2.247, P=0.025]. Conclusion:Fluoroscopic-guided SHNB is a safe, effective, and minimally invasive way to reduce pain and the opiate dose after UAE.

Superior hypogastric nerve block (SHNB) for pain control after uterine fibroid embolization (UFE): technique and troubleshooting.

BACKGROUND: Superior Hypogastric nerve Block (SHNB) has been shown to be an effective pain management technique after Uterine Fibroid Embolization (UFE), reducing the need for opiates and allowing same-day discharge after UFE. In this technical note we discuss relevant anatomy and technical details in performing SHNB. MAIN BODY: The Superior hypogastric plexus (SHP) is the part of the abdominopelvic sympathetic nervous system that provides a targeted intervention to sympathetic-mediated pain pathways of pelvic organs and a target for an anterior approach Superior Hypogastric nerve Block after embolization. Vascular structures are in close relation to the intended site of target of the SHP at the L5 vertebral body include aortic bifurcation and IVC confluence, hence a detailed knowledge of this is essential. A step by step technical approach to SHNB includes patient positioning for the block, image guidance and needle positioning, choice and technique of anesthetic injection. Traversing a large fibroid uterus, inadvertent vascular opacification and Local anesthetic systemic toxicity present challenges to performing the block and are addressed. CONCLUSION: Superior Hypogastric nerve Block (SHNB) can be a useful tool in the Interventional armamentarium to make UFE a better experience for patients with fibroids, allowing for better pain control as well as facilitating same day discharge. Performing SHNB appear to be can be performed with technical ease for an interventional radiologist.

Transecting the hypogastric nerve to uncover the bladder-inhibitory pathways involved with saphenous nerve stimulation in anesthetized rats.

Saphenous (SAFN) nerve stimulation was recently shown in anesthetized rats to elicit bladder-inhibitory responses in a frequency-dependent manner; however, the mechanism of action is unknown. The goal of this study was to investigate the potential role of the hypogastric nerve (HGN) in this inhibitory pathway by examining stimulation-evoked changes in bladder function under four different experimental conditions: (1) HGN intact, saline infusion (HGNi-s), (2) HGN transected, saline infusion (HGNt-s), (3) HGN intact, acetic acid (AA) infusion (HGNi-a), and (4) HGN transected, AA infusion (HGNt-a). Experiments were conducted in 33 urethane-anesthetized female rats, where continuous bladder infusion was provided through a suprapubic catheter. The experimental protocol involved two, 40-min stimulation trials in which electrical pulses were applied to the SAFN at a set frequency (10 Hz) and two different amplitudes (50 µA and 100 µA). In all experimental groups, SAFN stimulation resulted in complete suppression of bladder activity with an incidence rate of 25% to 50%. However, significant changes in the measured urodynamic changes (e.g., basal pressure, contraction amplitude, and inter-contraction interval) were found only in the HGNt-a animals. Our findings suggest that the HGN does not mediate the inhibitory effects of SAFN stimulation and that bladder inhibition is achieved through a different mechanism of action.

Anatomy of the female pelvic nerves: a macroscopic study of the hypogastric plexus and their relations and variations.

The autonomic nerves of the lesser pelvis are particularly prone to iatrogenic lesions due to their exposed position during manifold surgical interventions. Nevertheless, the cause of rectal and urinary incontinence or sexual dysfunctions, for example after rectal cancer resection or hysterectomy, remains largely understudied, particularly with regard to the female pelvic autonomic plexuses. This study focused on the macroscopic description of the superior hypogastric plexus, hypogastric nerves, inferior hypogastric plexus, the parasympathetic pelvic splanchnic nerves and the sympathetic fibres. Their arrangement is described in relation to commonly used surgical landmarks such as the sacral promontory, ureters, uterosacral ligaments, uterine and rectal blood vessels. Thirty-one embalmed female pelvises from 20 formalin-fixed and 11 Thiel-fixed cadavers were prepared. In all cases explored, the superior hypogastric plexus was situated anterior to the bifurcation of the abdominal aorta. In 60% of specimens, it reached the sacral promontory, whereas in 40% of specimens, it continued across the pelvic brim until S1. In about 25% of the subjects, we detected an accessory hypogastric nerve, which has not been systematically described so far. It originated medially from the inferior margin of the superior hypogastric plexus and continued medially into the presacral space. The existence of an accessory hypogastric nerve was confirmed during laparoscopy and by histological examination. The inferior hypogastric plexuses formed fan-shaped plexiform structures at the end of both hypogastric nerves, exactly at the junction of the ureter and the posterior wall of the uterine artery at the uterosacral ligament. In addition to the pelvic splanchnic nerves from S2-S4, which joined the inferior hypogastric plexus, 18% of the specimens in the present study revealed an additional pelvic splanchnic nerve originating from the S1 sacral root. In general, form, breadth and alignment of the autonomic nerves displayed large individual variations, which could also have a clinical impact on the postoperative function of the pelvic organs. The study serves as a basis for future investigations on the autonomic innervation of the female pelvic organs.

Response of hypogastric afferent fibers to bladder distention or irritation in cats.

The goal of this study in anesthetized cats was to identify silent hypogastric nerve (HGN) afferent fibers that do not respond to bladder distention but become responsive after chemical irritation of the bladder. The HGN was split into multiple filaments small enough for recording action potentials from single or multiple afferent fibers. The bladder was distended by infusion of either saline or 0.5% acetic acid (AA) through a urethral catheter while recording intravesical pressure. A total of 90 HGN filaments from 17 cats responded to bladder distention with saline or AA. Three types of HGN afferents were identified. The first type was non-nociceptive mechano-sensitive that responded to bladder distention at normal physiological pressures (10-40 cmH2O). The second type was nociceptive mechano-sensitive that only responded to high-pressure (50-80 cmH2O) bladder distention with saline but responded to low-pressure bladder distention after sensitization with AA. The third type was chemo-sensitive nociceptive that was silent even during high-pressure bladder distention but after sensitization with AA did respond to low-pressure bladder distention. These results indicate that HGN afferents as well as pelvic nerve afferents may play a role in bladder nociception. The HGN afferent fibers that are silent during bladder distention at normal physiological pressures but become responsive after chemical irritation are important for understanding the possible pathophysiological mechanism underlying bladder allodynia in painful bladder syndrome.

Efficacy of Intraprocedural Superior Hypogastric Nerve Block in Reduction of Postuterine Artery Embolization Narcotic Analgesia Use.

PURPOSE: Uterine artery embolization (UAE) is an effective treatment for the management of symptomatic uterine fibroids. We aim to evaluate the efficacy of superior hypogastric nerve block (SHNB) in reducing narcotic analgesia use for postprocedural pain after UAE. METHODS: A retrospective review of 88 consecutive patients with symptomatic fibroids who underwent UAE between August 2015 and August 2018 was performed. A total of 44 patients had intraprocedural SHNB and 44 patients had no SHNB. They were placed on a morphine patient-controlled anesthesia (PCA) pump after the procedure and were admitted for overnight observation. The total amount of PCA narcotic analgesia received was recorded for each patient. Additional factors including fibroid size, fibroid location, and patient age were evaluated to determine the predictors of narcotic use reduction after SHNB. RESULTS: The mean amount of postprocedural morphine use was 51.7 mg in patients who did not receive an SHNB versus 35.9 mg in patients who did receive an SHNB (P = .008), resulting in a 47.2% reduction in narcotic analgesia use in the SHNB cohort. A significant reduction in morphine use with SHNB was associated with fibroid size greater than 5 cm (P = .009), intramural fibroid location (P = .04), and patients 45 years or younger (P = .006). CONCLUSION: The use of SHNB could significantly reduce the amount of narcotic analgesia required for pain control after UAE with larger intramural fibroids and younger patients as predictors of increased efficacy.

Truncal regional nerve blocks in clinical anesthesia practice.

Regional anesthetic techniques are important components of successful multimodal analgesic strategies. When used successfully, truncal nerve blocks of the chest wall, abdomen, and, paraneuraxial nerves, in combination with other analgesic modalities, may offer similar analgesic efficacy as neuraxial techniques, which are associated with a greater risk profile. Moreover, in comparison to neuraxial techniques, truncal nerve blocks are relatively simple to perform and technically straightforward to learn. The transversus abdominus plane (TAP) block is often incorporated into the multimodal analgesia regimen for surgical patients undergoing various abdominal and gynecological procedures. Rectus sheath blocks (RSB) were originally introduced to help relax the anterior abdominal wall during surgery and as an adjunct pain therapy. With the advancement of technology and the development of ultrasound guided techniques, RSB now have a more ubiquitous role and have been shown to decrease postoperative pain and opioid consumption. Different variations of the quadratus lumborum block may provide visceral and sensory analgesic coverage. Moreover, truncal blocks, including ilioinguinal, iliohypogastric, pectoralis nerve (PECS) blocks, serratus anterior, intercostal, and erector spinae plane blocks, have gained routine clinical use for various surgeries. In this review, we discuss the techniques, anatomy, indications, complications, and benefits of truncal nerve blocks commonly used in clinical practice.

Neural interrelationships of autonomic ganglia from the pelvic region of male rats.

The aims of the present study were to describe, in male rats, the anatomical organization of the major and accessory pelvic ganglia (MPG, AG; respectively), the interrelationship of the pelvic plexus components, and the morphometry of the pelvic postganglionic neurons. Anatomical, histochemical and histological studies were performed in anesthetized adult Wistar male rats. We found that the pelvic plexus consists of intricate neural circuits composed of two MPG, and three pairs of AG (AGI, AGII, AGIII) anatomically interrelated through ipsilateral and contralateral commissural nerves. Around 30 nerves emerge from each MPG and 17 from AGI and AGII. The MPG efferent nerves spread out preganglionic information to several pelvic organs controlling urinary, bowel, reproductive and sexual functions, while AG innervation is more regional, and it is confined to reproductive organs located in the rostral region of the urogenital tract. Both MPG and AG contain nerve fascicles, blood vessels, small intensely fluorescent cells, satellite cells and oval neuronal somata with one to three nucleoli. The soma area of AG neurons is larger than those of MPG neurons (p < 0.005). The MPG contains about 75% of the total pelvic postganglionic neurons. Our findings corroborated previous reports about MPG inputs, and add new information regarding pelvic ganglia efferent branches, AG neurons (number and morphometry), and neural interrelationship between the pelvic plexus components. This information will be useful in designing future studies about the role of pelvic innervation in the physiology and pathophysiology of pelvic functions.

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.

Sensory pudendal nerve stimulation increases bladder capacity through sympathetic mechanisms in cyclophosphamide-induced cystitis rats.

AIMS: Interstitial cystitis and bladder pain syndrome is a prevalent health concern with inadequate treatments. Neuromodulation has emerged as a therapeutic option to treat patients refractory to standard care. The objective of this study was to determine the efficacy and mechanism(s) of sensory pudendal nerve stimulation on bladder function in cystitis rats. METHODS: Female rats were administered saline (n = 8) or cyclophosphamide (CYP, 150 mg/kg IP, n = 16) and single-trial cystometry experiments were conducted under urethane anesthesia 48 h after injection. Electrical stimulation (0.02-0.22 mA, 10-20 Hz) was delivered to the sensory branch of the pudendal nerve and its effect on the bladder and external urethral sphincter were measured. Stimulation trials were also conducted following bilateral hypogastric nerve transection (HGNT) or pharmacological inhibition of beta-adrenergic receptors (propranolol, 1 mg/kg IV) to determine the mechanisms of bladder inhibition. RESULTS: CYP-induced cystitis decreased bladder capacity (P = 0.0352) and bladder compliance (P = 0.024) by up to 38% of control. Electrical stimulation of the sensory pudendal nerve increased bladder capacity (P < 0.0001) in control and CYP rats by up to 51-52% of their respective baselines. HGNT did not influence bladder inhibition generated by sensory pudendal nerve stimulation in control rats, whereas HGNT and propranolol decreased the efficacy of electrical stimulation in CYP rats. CONCLUSIONS: Sympathetic reflex activity mediates sensory pudendal nerve stimulation in CYP treated but not control rats. These studies demonstrate an alternative approach to neuromodulation in cystitis and establish mechanistic changes during stimulation that may enable the development of novel therapeutics.