Background A comprehensive understanding of the anatomy of the obturator nerve after its emergence from the obturator foramen is essential when undertaking an obturator nerve block effectively. This study was conducted to provide precise anatomical guidance of the obturator nerve block with surface landmarks in the inguinal region. Materials and methods A cross-sectional observational study was carried out on 34 dissected embalmed cadaveric lower limbs to investigate anatomic variability of obturator nerve localization concerning bony/ligamentous landmarks viz. the pubic tubercle, anterior superior iliac spine, inguinal ligament, and femoral artery as well as the adductor longus. Results The pubic tubercle and inguinal ligament were found to be the \"least variable indicator\" and palpable landmark for localization of the main trunk of the obturator nerve exhibiting lesser standard deviation of the mean distance from the obturator nerve exit. Among the soft tissue (vessel/muscle) parameters, the shortest distance of the adductor longus muscle from the obturator nerve exit was found to have the lowest standard deviation, thus making it the most reliable parameter for obturator nerve localization. Conclusion High anatomic variability in the obturator nerve\'s localization does exist, and this explains the difficulty frequently encountered in the application of regional anesthetic techniques. The pubic tubercle and inguinal ligament points were found to be the least variable and most reliable landmarks for localization of the main trunk of the obturator nerve.

The femoral and obturator nerves both arise from the L2, L3, and L4 spinal nerve roots and descend into the pelvis before emerging in the lower limbs. The femoral nerve\'s primary function is knee extension and hip flexion, along with some sensory innervation to the leg. The obturator nerve\'s primary function is thigh adduction and sensory innervation to a small area of the medial thigh. Each may be injured by a variety of potential causes, many of them iatrogenic. Here, we review the anatomy of the femoral and obturator nerves and the clinical features and potential etiologies of femoral and obturator neuropathies. Their necessary investigations, including electrodiagnostic studies and imaging, their prognosis, and potential treatments, are discussed in this chapter.

BACKGROUND: The majority of small bowel obstructions (SBO) are caused by adhesion due to abdominal surgery. Internal hernias, a very rare cause of SBO, can arise from exposed blood vessels and nerves during pelvic lymphadenectomy (PL). In this report, we present two cases of SBO following laparoscopic and robot-assisted lateral lymph node dissection (LLND) for rectal cancer, one case each, of which obstructions were attributed to the exposure of blood vessels and nerves during the procedures.
METHODS: Case 1: A 68-year-old man underwent laparoscopic perineal rectal amputation and LLND for rectal cancer. Four years and three months after surgery, he visited to the emergency room with a chief complaint of left groin pain. Computed tomography (CT) revealed a closed-loop in the left pelvic cavity. We performed an open surgery to find that the small intestine was fitted into the gap between the left obturator nerve and the left pelvic wall, which was exposed by LLND. The intestine was not resected because coloration and peristalsis of the intestine improved after the hernia was released. The obturator nerve was preserved. Case 2: A 57-year-old man underwent a robot-assisted rectal amputation with LLND for rectal cancer. Eight months after surgery, he presented to the emergency room with a complaint of abdominal pain. CT revealed a closed-loop in the right pelvic cavity, and he underwent a laparoscopic surgery with a diagnosis of strangulated SBO. The small intestine was strangulated by an internal hernia caused by the right umbilical arterial cord, which was exposed by LLND. The incarcerated small intestine was released from the gap between the umbilical arterial cord and the pelvic wall. No bowel resection was performed. The umbilical arterial cord causing the internal hernia was resected.
CONCLUSIONS: Although strangulated SBO due to an exposed intestinal cord after PL has been a rare condition to date, it is crucial for surgeons to keep this condition in mind.

BACKGROUND: Chronic hip pain is one of the most common and difficult-to-treat causes of disability. Our study\'s primary aim was to investigate the effects of ultrasound and fluoroscopy-guided radiofrequency thermocoagulation of the femoral and obturator nerve articular branches on chronic hip pain, and the secondary aim was to determine its effects on hip function and quality of life.
METHODS: Fifty-three patients with hip pain lasting more than three months were enrolled in the study. VPS scale and WOMAC, SF-12 questionnaires were applied to the patients before and in the first, third, and sixth months following the procedure.
RESULTS: Of the patients, 60.4% were female, and 39.6% were male. Hip pain was caused by osteoarthritis in 77.1%, postoperative hip pain in 12.5%, malignancy in 8.3%, and avascular necrosis in 2.1%. The VPS scores were 8.9 ± 1.1 (mean±SD) in the baseline period, 2.4 ± 2.5 in the first postoperative week, 3.8 ± 2.5 in the first month, 5.1 ± 2.8 in the third month, and 5.8 ± 2.7 in the sixth month, with a significant decrease in VPS score (P < .001). One patient developed a motor deficit that improved spontaneously.
CONCLUSIONS: We concluded that radiofrequency thermocoagulation application to the articular branches of the femoral and obturator nerves provides pain relief, hip function improvement, and better quality of life (better physical component scores but no improvement in mental component scores in SF-12) for up to 6 months in chronic hip pain.

UNASSIGNED: Displaced acetabular fractures are complex injuries that necessitate precise surgical intervention. Obturator nerve injuries occur in approximately 2% of cases. The modified Stoppa approach, offering enhanced exposure of the quadrilateral plate, has gained attraction as an alternative technique for anterior acetabular fractures. However, its proximity to the obturator nerve poses a risk of iatrogenic injury. This study aimed to investigate the incidence of nerve injuries and functional outcomes in patients undergoing the modified Stoppa approach for traumatic acetabular fractures.
UNASSIGNED: This retrospective study involved 86 patients with anterior column fractures, whose data were prospectively collected. The fractures were treated using the modified Stoppa approach. Exclusion criteria were pathological fractures, alternative surgical approaches, prior nerve injuries, hip issues, refusal to participate, or inadequate follow-up. Data collection involved pre-operative imaging, thorough post-operative neurological assessments, and post-operative radiographic evaluation. Functional outcomes were assessed using the Harris Hip Score (HHS).
UNASSIGNED: Most patients were male (n=54) with a mean age of 40±17.3 years. Post-operative infection occurred in six cases, with resolution in four through antibiotics and two necessitating device removal. Obturator nerve damage was detected in 14 patients, comprising nine traumatic and five iatrogenic cases. During the follow-up, symptoms improved in all patients, except for the four patients with iatrogenic nerve damage.
UNASSIGNED: Traumatic nerve injuries generally heal naturally over time. In contrast, iatrogenic injuries have a less optimistic prognosis, potentially resulting in lasting neurological deficits.

Background This study aimed to compare ultrasound versus ultrasound with nerve stimulation-guided obturator nerve block (ONB) for the prevention of adductor spasm in patients undergoing transurethral resection of bladder tumor (TURBT). Methodology This randomized controlled study included 240 adult patients in the age group of 30 to 70 years undergoing TURBT for lateral and posterolateral wall bladder tumors who fulfilled the American Society of Anesthesiologists grade I and II criteria. The patients were divided into two groups: group U (n = 120) included patients who underwent ONB using an ultrasound-guided technique and group UN (n = 120) included patients who underwent ONB using ultrasound with the nerve stimulation technique. Block performance time, adductor jerks/spasms, adductor muscle power, and patient and surgeon satisfaction were compared. A P-value <0.05 was considered statistically significant. Results The mean block performance time in group U was significantly less (4.4 ± 0.82 minutes) than in group UN (6.55 ± 0.37 minutes). Compared to group U, group UN had significantly fewer adductor jerks/spasms during the surgery (7.76% vs. 20.35%, p = 0.006), significantly more surgeon satisfaction (92.24% vs. 79.65%, p = 0.006), significantly more patient satisfaction (92.24% vs. 79.65%, p = 0.006), and comparable complications (excessive bleeding and minor bladder injury) and adductor muscle power after the block (p > 0.05). Conclusions ONB using the nerve stimulation technique under ultrasound guidance has a longer mean block performance time, a higher success rate, and higher surgeon satisfaction than ONB under ultrasound guidance only.

BACKGROUND Neurilemmomas are rare tumors derived from the Schwann cells that comprise the peripheral nerve sheaths. They have a slow growth and rarely display malignancy. Early diagnosis is rare, and the treatment consists by surgical resection. Although robotic-assisted surgery is commonly used for treating retroperitoneal diseases, there are few reports of resection of retroperitoneal and pelvic schwannoma through robotic-assisted surgery. In the present study, we reported a case of complete excision of a benign retroperitoneal schwannoma of the obturator nerve by robotic-assisted surgery. CASE REPORT A 51-year-old woman was referred by her gynecologist for left pelvic discomfort of a 3-month duration. The physical examination was normal, but a computerized tomography scan of the abdomen and pelvis showed an expansive pelvic lesion in the topography of the left iliac vessels, a hypodense contrast enhancement measuring 4.6×3.4 cm. Magnetic resonance imaging showed an extraperitoneal lesion located medially and inferiorly to the left external iliac vessels, with a size of 4.9×3.7 cm, and of probable neural etiology. Surgical resection of the tumor was recommended because of the diagnostic hypothesis of obturator nerve schwannoma. CONCLUSIONS This case showed that retroperitoneal neurilemmomas are difficult to diagnose owing to a lack of specific symptoms, and the best treatment is complete tumor resection. The use of robotic techniques gives greater dexterity to the surgeon, since it provides high-definition 3-dimensional vision, which can make the removal of retroperitoneal tumors susceptible to minimally invasive resection in a safe and effective way.

The objective of our study was to compare the efficacy of sciatic and saphenous ultrasound nerve blocks with and without US-guided obturator nerve block in dogs undergoing tibial-plateau-levelling-osteotomy (TPLO) surgery. This study was developed in two phases: identification of an ultrasound window in the inguinal region for obturator nerve block and utilization of it in dogs undergoing TPLO. Dogs were assigned randomly to one of two groups: one received the three blocks with 0.5% ropivacaine (ON group) and the second one (NoON group) with NaCl instead of ropivacaine for the obturator block. In phase 1, the obturator nerve was visible between the pectineus and the abductor muscles and was approached using an in-plane technique. It was possible to use the ultrasound window for phase two. The number of dogs that received at least one bolus of intraoperative rescue analgesia in the NoON group (12/15 dogs) was significantly higher (p = 0.003) in comparison with the ON group (4/15). An ultrasound window to block the obturator nerve in the inguinal compartment with an in-plane technique was found. The use of this approach could produce adequate analgesia with less motor function impairment in dogs for TPLO surgery.

Uterine fibroids are the most common gynecologic tumors in reproductive-aged women with a prevalence of up to 80%. Symptoms can range from heavy vaginal bleeding and bulk symptoms to, less frequently, deep vein thrombosis and bowel obstruction.
A 32-year-old female patient presented with acute-onset of right groin and knee pain, and difficulty ambulating. A large posterior uterine fibroid was found to be compressing branches of the lumbar plexus, including the obturator nerve. The patient underwent gynecologic evaluation and an urgent laparoscopic myomectomy. Postoperatively, she had significant improvement in neurologic symptoms. She continued physical therapy for residual mild paresthesia and pain with prolonged ambulation.
Large pelvic masses such as uterine fibroids should be considered on the differential diagnosis for acute-onset non-gynecologic symptoms such as compressive neuropathy, which require urgent evaluation and possible surgical management.

In comparative anatomy, the adductor muscles are said to be quite variable and to often cause difficulty in separation. The arrangement of these muscles and the possible occurrence of the adductor minimus and obturator intermedius muscles in the albino rat has not been investigated. The aim of this study was to accurately describe the adductor muscles in the albino rat (Rattus norvegicus). We hypothesized that all adductor muscles are constantly present and can be separated in a constant manner, and that the adductor minimus and obturator intermedius muscles are constant structures. Both pelvic limbs of 30 formalin-embalmed male albino rats were carefully dissected. The identification of the individual muscles was made based on their position in relation to the two branches of the obturator nerve and by comparing our results with previous findings in other species including humans. All examined rats had two gracilis muscles. The adductor longus muscle was the most superficial and smallest individual. The adductor brevis split into two parts of insertion-the femoral and genicular parts. The adductor magnus and minimus muscles could be separated constantly. The obturator intermedius muscle was a constant structure next to the obturator externus muscle. The adductor muscles of the albino rat were constantly separable and could be clearly assigned to their names. Further research is needed to investigate these muscles, especially the obturator intermedius muscle, in other species including humans.