A radiological cadaveric study of obturator nerve involvement and cranial injectate spread after different approaches to the fascia iliaca compartment block.

Whether the fascia iliaca compartment block (FICB) involves the obturator nerve (ON) remains controversial. Involvement may require that the injectate spreads deep in the cranial direction, and might thus depend on the site of injection. Therefore, the effect of suprainguinal needle insertion with five centimeters of hydrodissection-mediated needle advancement (S-FICB-H) on ON involvement and cranial injectate spread was studied in this radiological cadaveric study. Results were compared with suprainguinal FICB without additional hydrodissection-mediated needle advancement (S-FICB), infrainguinal FICB (I-FICB), and femoral nerve block (FNB). Seventeen human cadavers were randomized to receive ultrasound-guided nerve block with a 40 mL solution of local anesthetic and contrast medium, on both sides. Injectate spread was objectified using computed tomography. The femoral and lateral femoral cutaneous nerves were consistently covered when S-FICB-H, S-FICB or FNB was applied, while the ON was involved in only one of the 34 nerve blocks. I-FICB failed to provide the same consistency of nerve involvement as S-FICB-H, S-FICB or FNB. Injectate reached most cranial in specimens treated with S-FICB-H. Our results demonstrate that even the technique with the most extensive cranial spread (S-FICB-H) does not lead to ON involvement and as such, the ON seems unrelated to FICB. Separate ON block should be considered when clinically indicated.

Anatomical and Radiological Assessments of Injectate Spread Stratified by the Volume of the Pericapsular Nerve Group Block.

BACKGROUND: The pericapsular nerve group (PENG) block was recently suggested as a regional technique for managing acute pain after hip surgery. However, few anatomical studies have confirmed the spread of injectate during the PENG block. This cadaver study aimed to analyze injectate spread to the target nerves during single-injection ultrasound-guided PENG block. METHODS: Ultrasound-guided PENG block with 3 different injectate volumes (10, 20, or 30 mL) was performed in 18 cadavers. Injectate spread by the volume was first evaluated on computed tomography, followed by cadaver dissection. The spread of the dye over the pelvis and lower limb was evaluated. RESULTS: The articular branches of the femoral nerve were stained nearly sufficiently with 20- and 30-mL specimens. The femoral nerve itself was stained simultaneously in six of 12 (50%) 20-mL specimens and 12 of 12 (100%) 30-mL specimens. The accessory obturator nerve was observed only in three (9%) of 36 specimens. The articular branches of the obturator nerve were rarely affected, regardless of injectate volume (1/12, 10 mL specimens; 2/12, 20 mL specimens; 1/12, 30 mL specimens; P > .999). Rather, the obturator nerve was affected. However, the obturator nerve was not stained consistently even with 30 mL of injectate (50%). CONCLUSIONS: After combining the dissection and radiological findings, the single-injection ultrasound-guided PENG blocks with volumes of 10, 20, and 30 mL do not support motor sparing or selective anterior hip capsule innervation in a clinical setting. If early rehabilitation is needed, high-volume PENG block might not be the ideal option, and persisting pain after PENG block might be attributed in part to the lack of obturator nerve articular branches blockade.

A case report of primary multiple obturator nerve schwannomas.

Primary multiple obturator nerve schwannomas originate from Schwann cells and are extremely rare. Patients with schwannomas are asymptomatic and a retroperitoneal schwannoma is often misdiagnosed as an adnexal mass. In the present study, we describe a 58-year-old woman in whom a right adnexal mass accompanied by endometrial polyp was found incidentally through transvaginal ultrasound. The mass was diagnosed as multiple obturator nerve schwannomas after laparoscopy. Immunohistochemical assay confirmed the schwannomas to be positive for SOX10. To our knowledge, this is the first report to demonstrate a case of multiple schwannomas originating from the obturator nerve and treated by laparoscopic resection.

Ultrasound-guided psoas compartment and sciatic nerve blocks for pain management of hind limb procedures in the alpaca (Vicugna pacos).

Background: Loco-regional anesthetic techniques are considered important in the multimodal approach to analgesia in both human and veterinary medicine. No such techniques are described in the alpaca, bar the use of epidural. This is in part due to the lack of anatomical description for this species. While this limitation exists, the use of ultrasound guidance makes peripheral nerve blocks a viable possibility in the alpaca. Case description: A 12-month-old alpaca was referred for the treatment of a septic left tarso-crural joint. Due to a poor prognosis, amputation of the limb under general anesthesia was performed. Sciatic and psoas compartment blocks were attempted with the ultrasound-guided injection of ropivacaine prior to the start of the procedure. While the femoral nerve was possible to visualize, no obturator nerve was identified. A 5-year old alpaca was also referred for a left hind lateral claw removal, due to a squamous cell carcinoma. The sciatic nerve block was performed prior to the claw amputation under general anesthesia. No changes in heart and respiratory rate, or blood pressure suggestive of nociception, were observed in either of these cases. At the end of both the procedures, the patients experienced uneventful recoveries characterized by the ability to maintain the standing position, interest in food, and normal behavior. Conclusion: This report identifies the ease of performance and the challenges encountered using the ultrasound-guided psoas compartment and sciatic nerve blocks in the alpaca. It is our hope that this report encourages the use of ultrasound-guided loco-regional techniques in this species.

Efecto analgésico del bloqueo PENG (grupo de nervios pericapsulares) en pacientes con fractura de cadera / Analgesic effect of the PENG BLOCK (pericapsular nervous group) in patients with hip fracture

Ultrasound regional blockade emerged that blocks the branches of the femoral nerve, obturator and accessory obturator that innervate the anterior hip capsule, the PENG block (group of pericapsular nerves), which by its Recent description does not have enough evidence in medical practice. To verify the analgesic effect of the PENG block in patients with hip fracture and its analgesic permanence during the first 10 hours after the block in patients admitted with a diagnosis of hip fracture, at the General Interzonal Hospital of Acute "Dr Oscar E Alende "From Mar del Plata, Argentina, in the months of May to November 2019. A prospective descriptive observational study was carried out with a total of 53 patients, hospitalized patients with a diagnosis of hip fracture, with standardized intravenous analgesic scheme and who have not yet undergone hip surgery. Pain was evaluated with the EVA scale (visual analog scale) prior to the blockage, and then at 30 min and 10 hours after the blockade, 15 ml of 1% lidocaine and 15 ml of bupivacaine at 0 were used. 25%, convex or linear ultrasound probe according to patient weight and 100 mm needle. In order to reproduce and evaluate the pain, the patients had a 30º flexion of the hip. Prior to the blockade, 66% of the patients had severe pain and 34% moderate pain, none presented mild pain or absence, both at thirty minutes and ten hours after the blockade, no patient presented severe pain and all patients presented analgesia with a decrease in more than three points on the VAS scale, in some cases reaching a decrease of 10 points on that scale. The PENG block is a regional anesthesia technique that provides very good analgesia to patients with hip fractures, therefore, it is an excellent saving strategy for systemic analgesics. Knowing the analgesia provided by the blockade at 30 min and at 10 h, it could be performed both in the preoperative period for the transfer and mobilization of the patient, as well as in the postoperative period, which could save the use of opioids and decrease hospital stay.

INTRODUCCIÓN La fractura de cadera es una emergencia ortopédica común en ancianos asociada a gran morbimortalidad, una adecuada analgesia regional perioperatoria determina un ahorro en el uso de analgésicos sistémicos. Recientemente, en el año 2018, surgió un nuevo bloqueo regional ecoguiado muy prometedor que bloquea las ramas del nervio femoral, obturador y obturador accesorio que inervan la capsula anterior de la cadera, el bloqueo PENG (grupo de nervios pericapsulares), el cual por su reciente descripción no cuenta con la suficiente evidencia en la práctica médica. OBJETIVOS: Comprobar el efecto analgésico del bloqueo PENG en pacientes con fractura de cadera y su permanencia analgésica durante las 10 primeras horas posteriores al bloqueo en los pacientes internados con diagnóstico de fractura de cadera, en el Hospital Interzonal General de Agudos "Dr. Oscar E Alende" de Mar del Plata, Argentina, en los meses de mayo a noviembre del 2019. MATERIALES Y MÉTODOS: Se realizó un estudio observacional descriptivo prospectivo con un total de 53 pacientes, se incluyeron pacientes internados con diagnóstico de fractura de cadera, con esquema analgésico endovenoso estandarizado y que aún no hayan sido sometido a cirugía de cadera. Se evaluó el dolor con la escala EVA (escala análoga visual) previo al bloqueo, y luego a los 30 min y a las 10 Hs de haber realizado el bloqueo, para este se utilizaron 15 ml lidocaína 1% y 15 ml de bupivacaína al 0,25%, sonda ecográfica convexa o lineal según el peso del paciente y aguja 100 mm. Para reproducir y evaluar el dolor se les realizo a los pacientes una flexión de 30º de la cadera. RESULTADOS: Previo al bloqueo el 66% de los pacientes tuvieron dolor severo y 34% dolor moderado, ninguno presentaba dolor leve o ausencia del mismo, tanto a los treinta minutos como a las diez horas posteriores al bloqueo ningún paciente presento dolor severo y todos los pacientes presentaron analgesia con una disminución en más de tres puntos en la escala de EVA, llegando en algunos casos a una disminución de 10 puntos de dicha escala. CONCLUSIONES: El bloqueo PENG es una técnica de anestesia regional que brinda muy buena analgesia a los pacientes con fractura de cadera, por consiguiente, es una excelente estrategia ahorradora de analgésicos sistémicos. Conociendo la analgesia que brinda el bloqueo a los 30 min y a las 10 h de realizado, se podría realizar dicho bloqueo tanto en el preoperatorio para el traslado y movilización del paciente, como en el post-operatorio, lo que podría ahorrar el uso de opioides y disminuir la estancia hospitalaria.

Obturator Intraneural Ganglion Cysts: Joint Connected and Underdiagnosed.

BACKGROUND: Intraneural ganglion cysts of the obturator nerve are rare. Our aim is to review cases of obturator intraneural ganglion cysts at our institution and those reported in the literature. METHODS: We reviewed all cases evaluated by the senior author. A literature search was performed using the PubMed database and Google Scholar with the following terms: "obturator cyst," "obturator intraneural ganglion cyst," and "obturator intraneural ganglia." All cases underwent a retrospective review. Patient demographic data, including age, sex, and presenting signs and symptoms were recorded. Imaging studies were re-evaluated by 2 musculoskeletal radiologists experienced in the diagnosis of intraneural ganglion cysts. RESULTS: We identified 2 cases of obturator intraneural ganglia at our institution; both were connected to the hip joint. We found 4 cases that were clearly diagnosed as intraneural ganglia in the literature, of which only 1 was recognized by the original authors as being joint connected, but based on our reinterpretation, 3 of 4 were joint connected. An additional 9 cases identified in the literature did not definitely report the nerve-cyst relationship, but based on our reinterpretation, were believed to be intraneural; 8 were joint connected. CONCLUSIONS: We believe that obturator intraneural ganglion cysts adhere to the principles of the unifying articular theory. They arise from the anteromedial hip joint and extend into an articular branch and can reach the parent obturator nerve. Surgery should address the hip disease and/or the articular branch connection. Not appreciating the pathoanatomy of these cysts can lead to persistent or recurrent cysts.

Gemelli-obturator complex in the deep gluteal space: an anatomic and dynamic study.

OBJECTIVE: To investigate the behavior of the sciatic nerve during hip rotation at subgluteal space. MATERIALS AND METHODS: Sonographic examination (high-resolution ultrasound machine at 5.0-14 MHZ) of the gemelli-obturator internus complex following two approaches: (1) a study on cadavers and (2) a study on healthy volunteers. The cadavers were examined in pronation, pelvis-fixed position by forcing internal and external rotations of the hip with the knee in 90° flexion. Healthy volunteers were examined during passive internal and external hip rotation (prone position; lumbar and pelvic regions fixed). Subjects with a history of major trauma, surgery or pathologies affecting the examined regions were excluded. RESULTS: The analysis included eight hemipelvis from six fresh cadavers and 31 healthy volunteers. The anatomical study revealed the presence of connective tissue attaching the sciatic nerve to the structures of the gemellus-obturator system at deep subgluteal space. The amplitude of the nerve curvature during rotating position was significantly greater than during resting position. During passive internal rotation, the sciatic nerve of both cadavers and healthy volunteers transformed from a straight structure to a curved structure tethered at two points as the tendon of the obturator internus contracted downwards. Conversely, external hip rotation caused the nerve to relax. CONCLUSION: Anatomically, the sciatic nerve is closely related to the gemelli-obturator internus complex. This relationship results in a reproducible dynamic behavior of the sciatic nerve during passive hip rotation, which may contribute to explain the pathological mechanisms of the obturator internal gemellus syndrome.

Ultrasound-Guided Obturator Nerve Block: A Focused Review on Anatomy and Updated Techniques.

This review outlines the anatomy of the obturator nerve and the indications for obturator nerve block (ONB). Ultrasound-guided ONB techniques and unresolved issues regarding these procedures are also discussed. An ONB is performed to prevent thigh adductor jerk during transurethral resection of bladder tumor, provide analgesia for knee surgery, treat hip pain, and improve persistent hip adductor spasticity. Various ultrasound-guided ONB techniques can be used and can be classified according to whether the approach is distal or proximal. In the distal approach, a transducer is placed at the inguinal crease; the anterior and posterior branches of the nerve are then blocked by two injections of local anesthetic directed toward the interfascial planes where each branch lies. The proximal approach comprises a single injection of local anesthetic into the interfascial plane between the pectineus and obturator externus muscles. Several proximal approaches involving different patient and transducer positions are reported. The proximal approach may be superior for reducing the dose of local anesthetic and providing successful blockade of the obturator nerve, including the hip articular branch, when compared with the distal approach. This hypothesis and any differences between the proximal ONB techniques need to be explored in future studies.

EFFICIENCY OF ULTRASOUND GUIDED LOWER LIMB PERIPHERAL NERVE BLOCKS IN PERIOPERATIVE PAIN MANAGEMENT FOR KNEE ARTHROSCOPY IN CHILDREN. A RANDOMIZED STUDY.

INTRODUCTION: Ultrasound guided lower limb peripheral nerve blocks are efficient for perioperative pain treatment in children. The aim was to see if lower limb peripheral nerve blocks reduced the amount of propofol and opioid analgesics used intraoperatively, as well as the level of pain and consumption of systemic analgesics postoperatively. MATERIAL AND METHODS: A randomized, prospective clinical trial was carried out. It included 60 children between 11 and 18 years of age scheduled for elective knee arthroscopy. The patients were divided into two groups. Group A received general anesthesia, group B received lower limb peripheral nerve blocks with sedation or general anesthesia. Postoperative level ofpain was assessed using visual analogue scale. RESULTS: Less propofol and fentanyl was used to induce and maintain anesthesia in group B (p < 0.001). The level of postoperative pain was significantly lower in group B (p < 0.001), as well as the postoperative consumption of analgesics (p < 0.001). As mahbny as 47% of the patients were discharged without receiving any analgesics postoperatively. The average duration of peripheral nerve blocks was 468 minutes. CONCLUSIONS: Ultrasound guided lower limb peripheral nerve blocks are an efficient technique of regional anesthesia in children. They reduce the amount of general anesthetics and opioid analgesics needed intraoperatively as well as the level of postoperative pain and consumption of analgesics postoperatively.

A new ultrasound-guided pubic approach for proximal obturator nerve block: clinical study and cadaver evaluation.

We evaluated an alternative technique for ultrasound-guided proximal level obturator nerve block that might facilitate needle visualisation using in-plane ultrasound guidance. Twenty patients undergoing transurethral bladder tumour resection requiring an obturator nerve block were enrolled into a prospective observational study. With the patient in the lithotomy position, the transducer was placed on the medial thigh along the extended line of the inguinal crease, and aimed cephalad to view a thick fascia between the pectineus and obturator externus muscles that contains the obturator nerve. A stimulating nerve block needle was inserted at the pubic region and advanced in-plane with the transducer in an anterior-to-posterior direction. Eight ml levobupivacaine 0.75% was injected within the fascia. The median (IQR [range]) duration for ultrasound identification of the target and injection were 8.5 (7-12 [5-24]) s and 62 (44.5-78.25 [39-383]) s, respectively. All blocks were successful. A cadaver evaluation demonstrated that the dye injected into the target fascia using our technique travelled retrogradely through the obturator canal, and surrounded the anterior and posterior branches of the obturator nerve both proximally and distally to the obturator canal. We believe that this is a promising new technique for ultrasound-guided proximal level obturator nerve block.

Ultrasound-guided obturator nerve block: interfascial injection versus a neurostimulation-assisted technique.

BACKGROUND AND OBJECTIVES: Interfascial injection of local anesthetic under ultrasound guidance has been proposed as a new technique for performing an obturator nerve block. We hypothesized that interfascial needle placement could supplant nerve stimulation as the end point for local anesthetic injection during ultrasound-guided obturator nerve block after the division of the obturator nerve. METHODS: Fifty spinal anesthesia patients who had experienced unilateral adductor muscle spasm during transurethral bladder tumor resection were randomly allocated to receive either 5 mL of lidocaine 2% injected under ultrasound guidance into the interfascial plane between the adductor longus and the adductor brevis and between the adductor brevis and the magnus muscles (US group) or an injection of 5 mL of lidocaine 2% in combination with nerve stimulation after identification of the divisions of the obturator nerve (USENS group). At 5, 10, and 15 minutes after block placement, muscle spasm was assessed by an independent observer masked to treatment allocation. The primary outcome was motor block onset time. Secondary outcomes were block performance time, total anesthesia-related time, motor block success at 15 minutes, and number of needle passes. RESULTS: Motor block onset time did not differ between the 2 groups (6.2 minutes for USENS versus 7.2 minutes for US group, P = 0.225), block performance time was longer in the USENS than in the US group (3.0 versus 1.6 minutes, P < 0.001), and total anesthesia-related time did not differ between the 2 groups (9.2 versus 8.9 minutes, P = 0.71). Block success rate at 15 minutes was 100% in the USENS group and 88% in the US group (P = 0.23). There was no difference in the number of needle passes (2.3 versus 2.1, P = 0.28). CONCLUSIONS: In ultrasound-guided obturator nerve block performed after the division of the nerve, injection of local anesthetic between the planes of the adductor muscles is comparable to nerve stimulation.

Ultrasound guided obturator nerve block: a single interfascial injection technique.

We describe a new technique of single interfascial injection for 25 patients scheduled for transurethral bladder tumor resection. An ultrasound probe was placed at the midline of inguinal crease and moved medially and caudally to visualize the fascial space between the adductor longus (or pectineus) and adductor brevis muscles. We injected 20 mL 1% lidocaine containing epinephrine into the interfascial space using a transverse plane approach to make an interfascial injection, not an intramuscular swelling pattern. And just distally, firm pressure was applied for 3 min. Afterwards, surgery was performed under spinal anesthesia. The time required for identification and location of the nerve was 20 ± 15 and 30 ± 15 s, respectively. Adductor muscle strength, which was measured with a sphygmomanometer, decreased in all patients, from 122 ± 26 mmHg before blockade to 63 ± 11 mmHg 5 min after blockade. No movement or palpable muscle twitching occurred in 23 cases, slight movement of the thigh not interfering with the surgical procedure was observed in 1 case, thus the obturator reflex was successfully inhibited in 96% of cases. Ultrasound-guided single interfascial injection is an easy and successful technique for obturator nerve block.

[Ultrasound-guided combined femoral-obturator nerve block for the knee arthroscopic surgery of meniscal lesions: case report].

We report successful management of anesthesia in two cases of knee arthroscopic surgery of meniscal lesions using ultrasound-guided combined femoral-obturator nerve block with inhalation anesthesia. The blocks were performed with 30 ml of 0.5% ropivacaine under ultrasonographic visualization. The perioperative courses were uneventful and there was no complaint about postoperative pain. Unlike spinal or epidural anesthesia, combined femoral-obturator nerve block has advantages of no muscle weakness in healthy lower limbs, no urinary retention, and no post dural puncture headache. Our technique relieved postoperative pain effectively because knee joint is innervated by the femoral and obturator nerves in great measure. Ultrasound-guided femoral and obturator nerve block is easier and more successful than sciatic nerve block. General anesthesia with combined femoral-obturator nerve block could be a useful technique with less complication for knee arthroscopic surgery.

Ultrasound-guided peripheral nerve blocks for anterior cruciate ligament reconstruction: effect of obturator nerve block during and after surgery.

PURPOSE: Three studies were conducted to determine whether and how the obturator nerve bears relevance to intra- and postoperative pain in patients undergoing anterior cruciate ligament (ACL) reconstruction using a hamstring autograft. METHODS: Patients undergoing arthroscopic ACL reconstruction using a hamstring autograft were enrolled in three studies. In the first study, we studied the analgesic effect of combined posterior lumbar plexus (PLP) and sciatic nerve blocks as well as combined femoral, lateral femoral cutaneous, and sciatic nerve blocks during and for 24 h after surgery. The second study was conducted to compare the analgesic effect of the combination of femoral, lateral femoral cutaneous, and sciatic nerve blocks with and without an obturator nerve block. Finally, we compared a postoperative continuous femoral nerve block and PLP block both during and for 48 h after surgery. RESULTS: In the first study, patients receiving the PLP block required significantly less fentanyl intraoperatively than those given the femoral nerve block. In the second, significantly less fentanyl was required during surgery for patients with the obturator nerve block than for those without. Finally, the continuous postoperative PLP block showed higher visual analog pain scores than those with the continuous femoral nerve block during movement at 48 h. CONCLUSION: The present results suggest the involvement of the obturator nerve in ACL reconstruction using a hamstring autograft. However, although obturator nerve blockade is crucial for intraoperative analgesia, a continuous obturator nerve block is not necessary beyond 24 h postoperatively.

Ultrasound-guided obturator nerve block: an interfascial injection approach without nerve stimulation.

BACKGROUND AND OBJECTIVES: For knee surgery, obturator nerve block (ONB) has been shown to enhance postoperative analgesia provided by femoral block. Current techniques for obturator block use surface landmarks or ultrasound guidance (USG) with nerve stimulation. This preliminary observational study evaluated the success of an ultrasound-guided ONB without the additional use of nerve stimulation. METHODS: Thirty patients scheduled for knee surgery under general anesthesia with nerve block for postoperative analgesia had ONB performed using USG and injection of 10 mL 0.5% ropivacaine with epinephrine. Half of the ropivacaine was injected between the pectineus and adductor brevis muscles, and half between the adductor brevis and adductor magnus muscles. The strength of thigh adduction was measured at 5, 10, and 15 mins after injection, and 50% strength reduction at 15 mins indicated a successful block. RESULTS: All patients showed reduction of strength, and 28 of 30 or 93% met the criteria for successful block with mean strength reduction of 82.2% (SD, 21.6%) at 15 mins. Blocks were completed in 122 secs (SD, 33 secs). CONCLUSIONS: Obturator nerve block using USG to achieve interfascial injection without nerve stimulation had success similar to that reported in studies using nerve stimulation.