Obturator neuropathy: causes and outcome

Femoral and obturator neuropathies

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.

Nerve entrapment syndromes of the lower limb: a pictorial review

Peripheral nerves of the lower limb may become entrapped at various points during their anatomical course. While clinical assessment and nerve conduction studies are the mainstay of diagnosis, there are multiple imaging options, specifically ultrasound and magnetic resonance imaging (MRI), which offer important information about the potential cause and location of nerve entrapment that can help guide management. This article overviews the anatomical course of various lower limb nerves, including the sciatic nerve, tibial nerve, medial plantar nerve, lateral plantar nerve, digital nerves, common peroneal nerve, deep peroneal nerve, superficial peroneal nerve, sural nerve, obturator nerve, lateral femoral cutaneous nerve and femoral nerve. The common locations and causes of entrapments for each of the nerves are explained. Common ultrasound and MRI findings of nerve entrapments, direct and indirect, are described, and various examples of the more commonly observed cases of lower limb nerve entrapments are provided.Critical relevance statement This article describes the common sites of lower limb nerve entrapments and their imaging features. It equips radiologists with the knowledge needed to approach the assessment of entrapment neuropathies, which are a critically important cause of pain and functional impairment.Key points• Ultrasound and MRI are commonly used to investigate nerve entrapment syndromes.• Ultrasound findings include nerve hypo-echogenicity, calibre changes and the sonographic Tinel's sign.• MRI findings include increased nerve T2 signal, muscle atrophy and denervation oedema.• Imaging can reveal causative lesions, including scarring, masses and anatomical variants.

Nerve Entrapments in the Pelvis and Hip

Clinical symptoms of pelvic entrapment neuropathies are widely variable and frequently nonspecific, thus rendering it difficult to localize and diagnose. Magnetic resonance imaging (MRI), and in particular MR neurography, has become increasingly important in the work-up of entrapment neuropathies involving the pelvic and hip nerves of the lumbosacral plexus. The major sensory and motor peripheral nerves of the pelvis and hip include the sciatic nerve, superior and inferior gluteal nerves, femoral nerve, lateral femoral cutaneous nerve, obturator nerve, and pudendal nerve. Familiarity with the anatomy and imaging appearance of normal and pathologic nerves in combination with clinical presentation is crucial in the diagnosis of entrapment neuropathies.

Neoplastic nerve lesions

Though metastasis and malignant infiltration of the peripheral nervous system is relatively rare, physicians should have a familiarity with their presentations to allow for prompt diagnosis and initiation of treatment. This article will review the clinical presentations, diagnostic evaluation, and treatment of neoplastic involvement of the cranial nerves, nerve roots, peripheral nerves, and muscle. Due to the proximity of the neural structure traversing the skull base, metastasis to this region results in distinctive syndromes, most often associated with breast, lung, and prostate cancer. Metastatic involvement of the nerve roots is uncommon, apart from leptomeningeal carcinomatosis and bony metastasis with resultant nerve root damage, and is characterized by significant pain, weakness, and numbness of an extremity. Neoplasms may metastasize or infiltrate the brachial and lumbosacral plexuses resulting in progressive and painful sensory and motor deficits. Differentiating neoplastic involvement from radiation-induced injury is of paramount importance as it dictates treatment and prognosis. Neurolymphomatosis, due to malignant lymphocytic infiltration of the cranial nerves, nerve roots, plexuses, and peripheral nerves, deserves special attention given its myriad presentations, often mimicking acquired demyelinating neuropathies.

Sonoanatomy of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves: a practical guide for US-guided injections

The ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves are the major sensory nerves that may be involved in chronic groin and genital pain with a significant impact on the quality of life of patients. The diagnosis remains clinical, and US-guided diagnostic injections using an anesthetic may aid in confirming the clinical suspicion. The anatomy of the peripheral nerves can be successfully studied using imaging. High-resolution ultrasound is increasingly used in the clinical setting for visualizing small peripheral nerves, and magnetic resonance imaging provides an anatomical overview of the relationship between small nerves and surrounding structures. In this pictorial assay, we review the anatomy and clinical relevance of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves. We summarize the various techniques for ultrasound identification, and present the ultrasound-guided infiltration techniques for injecting the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves. Corresponding magnetic resonance images and clinical photos of the probe placement technique are provided for anatomical correlation. This paper is aimed to serve as a practical technical guide for physicians to familiarize themselves with the ultrasound anatomy of the major inguinal sensory nerves and to enable successful ultrasound identification and ultrasound-guided diagnostic or therapeutic infiltrations for pain management of the ilioinguinal, iliohypogastric, genitofemoral, obturator, and pudendal nerves.

Electrodiagnostic Assessment of Uncommon Mononeuropathies

Carpal tunnel syndrome, ulnar neuropathy at the elbow, and peroneal neuropathy are the most common mononeuropathies; however, other individual nerves may also be injured by various processes. These uncommon mononeuropathies may be less readily diagnosed owing to unfamiliarity with the presentations and vague symptoms. Electrodiagnostic studies are essential in the evaluation of uncommon mononeuropathies and can assist in localization and prognostication. However, they can also be challenging; stimulation at the proximal sites is difficult and well-validated reference values are not available. This article reviews the electrodiagnostic assessment of several uncommon upper and lower extremities mononeuropathies.

Obturator nerve impingement caused by an osteophyte in the sacroiliac joint: A case report

BACKGROUND

Cases of obturator nerve impingement (ONI) caused by osteophytes resulting from bone hyperplasia on the sacroiliac articular surface have never been reported. This paper presents such a case in a patient in whom severe lower limb pain was caused by osteophyte compression of the sacroiliac joint on the obturator nerve.

CASE SUMMARY

A 65-year-old Asian man presented with severe pain and numbness in his left lower limb, which became aggravated during walking and showed intermittent claudication. The physical examination revealed that the muscle strength of the left lower limb had decreased and that the passive knee flexion test result was positive. Computed tomography (CT) and 3D reconstruction showed a large osteophyte located in the anterior lower part of the left sacroiliac joint. The results of electrophysiological examination showed peripheral neuropathy. A CT-guided obturator nerve block significantly reduced the severity of pain in this patient. According to the above findings, ONI caused by the osteophyte in the sacroiliac joint was diagnosed. This patient underwent an operation to remove the bone spur and symptomatic treatment. After therapy, the patient's pain and numbness were significantly relieved. The last follow-up was performed 6 mo after the operation, and the patient recovered well without other complications, returned to work, and resumed his normal lifestyle.

CONCLUSION

Osteophytes of the sacroiliac joint can cause ONI, which leads to symptoms including severe radiative pain in the lower limb in patients. The diagnosis and differentiation of this disease should attract the attention of clinicians. Surgical excision of osteophytes should be considered when conservative treatment is not effective.

Clinico-radiological review of peripheral entrapment neuropathies - Part 2 Lower limb

PURPOSE

This review discusses the relevant anatomy, etiopathogenesis, current notions in clinical and imaging features as well as management outline of lower limb entrapment neuropathies.

METHODS

The review is based on critical analysis of the current literature as well as our experience in dealing with entrapment neuropathies of the lower limb.

RESULTS

The complex anatomical network of nerves supplying the lower extremities are prone to entrapment by a heterogenous group of etiologies. This leads to diverse clinical manifestations making them difficult to diagnose with traditional methods such as clinical examination and electrodiagnostic studies. Moreover, some of these may mimic other common conditions such as disc pain or fibromyalgia leading to delay in diagnosis and increasing morbidity. Addition of imaging improves the diagnostic accuracy and also help in correct treatment of these entities. Magnetic resonance imaging is very useful for deeply situated nerves in pelvis and thigh while ultrasound is well validated for superficial entrapment neuropathies.

CONCLUSION

The rapidly changing concepts in these conditions accompanied by the advances in imaging has made it essential for a clinical radiologist to be well-informed with the current best practices.

Plexus and peripheral nerve metastasis

Cancer in the form of solid tumors, leukemia, and lymphoma can infiltrate and metastasize to the peripheral nervous system, including the cranial nerves, nerve roots, cervical, brachial and lumbosacral plexuses, and, rarely, the peripheral nerves. This review discusses the presentation, diagnostic evaluation, and treatment options for metastatic lesions to these components of the peripheral nervous system and is organized based on the anatomic distribution. As skull base metastases (also discussed in Chapter 14) result in cranial neuropathies, these will be covered in detail, as well as cancers that directly infiltrate the cranial nerves. Particular emphasis is placed on the clinical, imaging, and electrodiagnostic features that differentiate neoplastic plexopathies from radiation-induced plexopathies. Neurolymphomatosis, in which malignant lymphocytes invade the cranial nerves, nerve roots, brachial and lumbosacral plexuses, and peripheral nerves, is a rare manifestation of lymphoma and leukemia. Diagnoses of neurolymphomatosis are often missed or delayed given its varied presentations, resulting in poorer outcomes. Thus this disease will also be discussed in depth.

Perineural tumor spread of bladder cancer causing lumbosacral plexopathy: an anatomic explanation

We present two cases of biopsy-proven neoplastic lumbosacral plexopathy from perineural spread of bladder cancer: one patient presented with predominantly sciatic nerve involvement and the second predominantly with obturator nerve involvement. These two patterns of perineural spread from bladder cancer were supported by imaging in our cases and solidified by review of the literature. Based on the innervation of the bladder, we provide an anatomic explanation for this observation. To our best knowledge, such an anatomic, mechanistic basis for perineural tumor spread in bladder cancer has not yet been described.

Acetabular paralabral cyst as a rare cause of obturator neuropathy: a case report

An acetabular paralabral cyst is a benign soft tissue cyst usually seen in association with a tear of the acetabular labrum. Acetabular paralabral cysts are often the cause of joint pain, but they rarely cause compression of the adjacent neurovascular structures. We present a case of a 63-year-old male patient who had paresis and atrophy of right hip adductor muscles. Right obturator neuropathy was confirmed through an electrodiagnostic study. In addition, magnetic resonance imaging showed a paralabral cyst in the right acetabulum which extended to the pelvic wall. The patient underwent conservative treatment without surgical procedure. The pain was decreased after 1 month of conservative therapy. The pain was decreased at the 1-month follow-up. Follow-up electromyography showed polyphasic motor unit potentials in adductor magnus and adductor longus muscles. Based on the experience of this case, an acetabular paralabral cyst should be considered as one of the rare causes of obturator neuropathy.

Successful obturator nerve repairing: Intraoperative sural nerve graft harvesting in endometrium cancer patient

INTRODUCTION

Intraoperative injury of obturator nerve is a rare complication of gynecologic surgeries, it has been reported especially in patients with endometriosis and genitourinary malignancies. Gynecologic patients undergoing open lymphadenectomy are at increased risk of obturator nerve injury.

PRESENTATION OF CASE

A 60-year-old woman with FIGO stage II Grade II endometrial adenocarcinoma underwent bilateral pelvic paraaortic lymphadenectomy. During right obturator lymph node dissection, the right obturator nerve was inadvertently transected with Harmonic scalpel sealing system. The graft was used to anastomose epyneurium of distal segment of obturator nerve to its counterpart in the proximal segment with 10–0 prolen suture.

DISCUSSION

In case of iatrogenic nerve transection, microsurgical end to end tension-free coaptation is advocated. In case of the obturator nerve is fixed and because of the thermal injury end to end alignment can not be achieved, nerve grafting is necessary.

CONCLUSION

According to our knowledge, successful immediate grafting of iatrogenically damaged obturator nerve during pelvic lymphadenectomy in our patient is the third report of such a case, but also it has a unique feature of being the first obturator nerve repairing case after dissected with tissue sealing system which causes large sealed area that does not make it possible to make end-to-end anastomosis without nerve harvesting.

High-resolution 3-T MR neurography of the lumbosacral plexus

The lumbosacral plexus comprises a network of nerves that provide motor and sensory innervation to most structures of the pelvis and lower extremities. It is susceptible to various traumatic, inflammatory, metabolic, and neoplastic processes that may lead to lumbrosacral plexopathy, a serious and often disabling condition whose course and prognosis largely depend on the identification and cure of the causative condition. Whereas diagnosis of lumbrosacral plexopathy has traditionally relied on patients' medical history, clinical examination, and electrodiagnostic tests, magnetic resonance (MR) neurography plays an increasingly prominent role in noninvasive characterization of the type, location, and extent of lumbrosacral plexus involvement and is developing into a useful diagnostic tool that substantially affects disease management. With use of 3-T MR imagers, improved coils, and advanced imaging sequences, which provide exquisite spatial resolution and soft-tissue contrast, MR neurography provides excellent depiction of the lumbrosacral plexus and its peripheral branches and may be used to confirm a diagnosis of lumbrosacral plexopathy with high accuracy or provide superior anatomic information should surgical intervention be necessary.

Neurology of pregnancy

Pregnancy creates alterations in maternal physiology which predispose to unique neurologic disorders. Pre-eclampsia, eclampsia, certain types of ischemic and hemorrhagic stroke, reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome, and thunderclap headache all appear to share a common origin from vascular endothelial dysfunction, with overlapping clinical presentations. Multiple sclerosis often improves during pregnancy. Compression mononeuropathies may occur in the extremities. Myasthenia gravis may affect second stage labor. Various inflammatory peripheral neuropathies, dystrophies, myopathies may occur during pregnancy. The safety of specific immune suppressants is reviewed. Epilepsy does not have a significant effect upon the course of pregnancy, albeit there is a modest increase in the need for cesarean section. Certain antiepileptic drugs may produce fetal malformations, most notably valproic acid. Brain tumors are rare during pregnancy, but may increase in size due to activation of hormonal receptors on tumor cells surfaces, water retention, and engorged blood vessels.

Pelvic radiculopathies, lumbosacral plexopathies, and neuropathies in oncologic disease: a multidisciplinary approach to a diagnostic challenge

The purpose of this article is to familiarize the reader with the anatomy of the major pelvic nerves and the clinical features of associated lumbosacral plexopathies. To demonstrate this we illustrate several cases of malignant lumbosacral plexopathy on computed tomography, magnetic resonance imaging, and positron emission tomography/computed tomography. A new lumbosacral plexopathy in a patient with a prior history of abdominal or pelvic malignancy is usually of malignant etiology. Biopsies may be required to definitively differentiate tumour from posttreatment fibrosis, and in cases of inconclusive sampling or where biopsies are not possible, follow-up imaging may be necessary. In view of the complexity of clinical findings often confounded by a history of prior surgery and/or radiotherapy, a multidisciplinary approach between oncologists, neurologists, and radiologists is often required for what can be a diagnostic challenge.

[The conflict between obturator nerve and ovary: a cadaveric and radioanatomic study]

The aim of this study was to describe the anatomical relationships between the ovary and the obturator nerve in its intrapelvic portion. Seven embalmed cadavers were dissected; 20 MRIs were then analyzed. The main distance between the lateral pole of the ovary and the obturator nerve was 29 mm. The authors describe various etiologies responsible for obturator neuralgia. An underdiagnosed cause is gonadal hypertrophy.

Magnetic resonance neurography of the pelvis and lumbosacral plexus

Recent advances in magnetic resonance (MR) imaging have revolutionized peripheral nerve imaging and made high-resolution acquisitions a clinical reality. High-resolution dedicated MR neurography techniques can show pathologic changes within the peripheral nerves as well as elucidate the underlying disorder or cause. Neurogenic pain arising from the nerves of the pelvis and lumbosacral plexus poses a particular diagnostic challenge for the clinician and radiologist alike. This article reviews the advances in MR imaging that have allowed state-of-the-art high-resolution imaging to become a reality in clinical practice.

Entrapment neuropathies of the lower extremity

Neuropathies that affect the lower limbs are often encountered after trauma or iatrogenic injury or by entrapment at areas of anatomic restriction. Symptoms may initially be masked by concomitant trauma or recovery from surgical procedures. The nerves that serve the lower extremities arise from the lumbosacral plexus, formed by the L2-S2 nerve roots. The major nerves that supply the lower extremities are the femoral, obturator, lateral femoral cutaneous, and the peroneal (fibular) and tibial, which arise from the sciatic nerve, and the superior and inferior gluteal nerves. An understanding of the motor and sensory functions of these nerves is critical in recognizing and localizing nerve injury. Electrodiagnostic studies are an important diagnostic tool. A well-designed electromyography study can help confirm and localize a nerve lesion, assess severity, and evaluate for other peripheral nerve lesions, such as plexopathy or radiculopathy.

Compression and entrapment neuropathies

Peripheral nerve entrapments are frequent. They usually appear in anatomical tunnels such as the carpal tunnel. Nerve compressions may be due to external pressure such as the fibular nerve at the fibular head. Malignant or benign tumors may also damage the nerve. For each nerve from the upper and lower limbs, detailed clinical, electrophysiological, imaging, and therapeutic aspects are described. In the upper limbs, carpal tunnel syndrome and ulnar neuropathy at the elbow are the most frequent manifestations; the radial nerve is less frequently involved. Other nerves may occasionally be damaged and these are described also. In the lower limbs, the fibular nerve is most frequently involved, usually at the fibular head by external compression. Other nerves may also be involved and are therefore described. The clinical and electrophysiological examination are very important for the diagnosis, but imaging is also of great use. Treatments available for each nerve disease are discussed.

Bilateral obturator neuropathy caused by an intrapelvic fibrosarcoma with myofibroblastic features in a dog

A nine-year-old female Rottweiler presented with a 6-week history of progressive impairment of hindlimb adduction. Clinical examination showed abduction of both hind legs when walking on a smooth surface, pain at the medial surface of the left thigh, and an intrarectal palpable mass at the pelvic floor. Electromyography demonstrated fibrillation potentials in the adductor muscles on both sides. Pelvic radiographs showed severe osteolysis of the ischium. Gross post-mortem examination following euthanasia disclosed a large retroperitoneal mass, invading the obturator foramina and compressing both obturator nerves. Histopathological examination revealed a high-grade anaplastic sarcoma. Immunohistochemically, the tumour cells labelled positively for vimentin and alpha-smooth muscle actin, hence the tumour was considered a "myofibroblastic fibrosarcoma". This unique case report describes a novel cause of obturator neuropathy in veterinary medicine. To date, clinical descriptions of obturator nerve lesions have been limited to pelvic fractures in small animals and following difficult labour in large animals.

Electrodiagnostic evaluation of lower extremity mononeuropathies

This article discusses the anatomy of lower limb mononeuropathies and reviews the general approach to evaluating patients in the electrodiagnostic laboratory with suspected mononeuropathies of the lower limb. Through illustrative cases of patients presenting with a floppy foot, buckling knee, or painful foot, the approaches using nerve conduction studies and needle electromyography are reviewed, and the pattern of findings of peroneal, tibial, sciatic, femoral, and obturator neuropathies is shown.

MR imaging mapping of skeletal muscle denervation in entrapment and compressive neuropathies

The diagnoses of entrapment and compressive neuropathies have been based on the findings from clinical examinations and electrophysiologic tests, such as electromyography and nerve conduction studies. The use of magnetic resonance (MR) imaging for the diagnosis of entrapment or compressive neuropathies is increasing because MR imaging is particularly useful for discerning potential causes and for identifying associated muscle denervation. However, it is sometimes difficult to localize nerve entrapment or demonstrate nerve compression lesions with MR imaging. Nevertheless, even in these cases, MR imaging may show denervation-associated changes in specific muscles innervated by the affected nerves. The analysis of denervated muscle distributions by using MR imaging, with a knowledge of nerve innervation patterns, would be helpful for determining the nerves involved and the levels of nerve entrapment or compression. In this context, the mapping of skeletal muscle denervation with MR imaging has a supplementary or even a primary role in the diagnosis of entrapment and compressive neuropathies.

Femoral branch to obturator nerve transfer for restoration of thigh adduction following iatrogenic injury

Obturator nerve injury is a rare complication of pelvic surgery. A variety of management strategies have been reported, with conservative measures being the preferred treatment in most cases. While nerve transfer has become more commonly used for restoring brachial plexus injuries, it has rarely been applied to the lower extremities. To the authors' knowledge, this is the first report of an obturator nerve neurotization. A patient presented 7 months after an iatrogenic right obturator nerve palsy due to pelvic surgery for gynecological malignancy. She underwent a femoral branch to obturator nerve transfer to restore right thigh adduction. Ten months after the neurotization procedure, there was electromyographic evidence of almost complete obturator nerve reinnervation. At 1 year postoperatively, the patient had regained full muscle strength on thigh adduction and a normal gait. Nerve transfer could therefore be a good option in patients with obturator nerve injury whose symptoms fail to respond to conservative medical therapy.

Pathways of extrapelvic spread of pelvic disease: imaging findings

The complex extraperitoneal anatomy of the pelvis includes various outlets for the transit of organs and neurovascular structures to the rest of the body. These outlets include the greater sciatic foramen, lesser sciatic foramen, inguinal canal, femoral triangle, obturator canal, anal and genitourinary hiatuses of the pelvic floor, prevesical space, and iliopsoas compartment. All of these structures serve as conduits for the dissemination of malignant and benign inflammatory diseases from the pelvic cavity and into the soft-tissue structures of the abdominal wall, buttocks, and upper thigh. Knowledge of the pelvic anatomy is crucial to understand these patterns of disease spread. Cross-sectional imaging provides important anatomic information and depicts the extent of disease and its involvement of surrounding extrapelvic structures, information that is important for planning surgery and radiation therapy.

[Management of chronic postoperative pelvic and perineal pain due to parietal somatic nerve damage]

INTRODUCTION

All surgical procedures require an incision with a risk of nerve damage at the site of the scar or as a result of fibrotic scar tissue. The purpose of this article is to describe the management of chronic postoperative pelvic and perineal pain due to parietal somatic nerve damage.

PATIENTS AND METHODS

A comprehensive review of the literature was performed by searching PUBMED for articles on the management of chronic postoperative pelvic and perineal pain due to parietal somatic nerve damage.

RESULTS

Postoperative lesions of parietal somatic nerves (ilioinguinal, iliohypogastric, genitofemoral, pudendal, obturator, femoral) are frequent after pelvic surgery. Clinical examination of the scars (trigger zone) and detailed analysis of the topography and type of pain are essential elements in the analysis of this pain. Infiltration of local anaesthetic at the trigger point or along the nerve has a diagnostic value. Corticosteroid infiltrations and minimally invasive treatments such as pulsed radiofrequency have provided more or less lasting improvement of the symptoms. Surgical nerve release together with resection of fibrosis and removal of prosthetic material provides good long-term results. The surgical approach depends on the nerve concerned and the level of the lesion.

CONCLUSION

The management of chronic postoperative pelvic and perineal pain due to parietal somatic nerve damage is based on local infiltration of anaesthetics and corticosteroids. Nerve release surgery with resection of fibrosis provides the best long-term results.

[Symptomatic approach to chronic neuropathic somatic pelvic and perineal pain]

OBJECTIVES

To determine the characteristics of neuropathic pain and the somatic nerve lesions most frequently encountered in the context of chronic pelvic and perineal pain.

MATERIAL AND METHODS

Review of the literature devoted to pelvic and perineal neuralgia.

RESULTS

The diagnosis of pelvic and perineal pain related to a somatic nerve lesion is essentially clinical. The topography of the pain and its characteristics (burning, paraesthesia, etc.) can help to link the pain to the neurological territory involved. Complementary investigations are poorly contributive. Two main systems are involved in this region: sacral nerve roots that give rise to the pudendal nerve and the posterior cutaneous nerve of the thigh, thoracolumbar nerve roots that give rise to the ilioinguinal, iliohypogastric, genitofemoral and obturator nerves. The first system is essentially perineal and the second is essentially anterior inguinoperineal.

DISCUSSION

Pudendal neuralgia is the most common and most disabling form of pelvic pain. It presents as unilateral or bilateral burning pain of the anterior or posterior perineum that is worse on sitting and relieved by standing, not usually associated with night pain. It is related to a ligamentous nerve compression mechanism. Inferior cluneal neuralgia tends to be experienced as ischial and lateroperineal pain, and is sometimes accompanied by pain in a truncated sciatic territory, corresponding to projections of the posterior cutaneous nerve of the thigh. This neuralgia can be related to a piriformis syndrome or an ischial lesion. Sacral nerve root lesions do not cause acute pain, but are accompanied by sacral sensory loss and urinary, anorectal or sexual disorders. Pain related to ilioinguinal, iliohypogastric and genitofemoral nerves is generally secondary to surgical trauma and scars. Although these various lesions are sometimes difficult to distinguish from each other, an essential part of management consists of performing a local anesthetic block at the trigger point detected in the scar. Referred pain derived from the spinal cord due to thoracolumbar painful minor intervertebral dysfunction is experienced in the inguinal region, pubis, labium majorum and sometimes the trochanter, and only a complete clinical examination of the thoracolumbar region can demonstrate local signs (posterior facet joint pain at several levels, fibromyalgia).

Pelvic nerve injury following gynecologic surgery: a prospective cohort study

OBJECTIVE

The purpose of this study was to determine the incidence and time course of postoperative neuropathy resulting from gynecologic surgery.

STUDY DESIGN

A single cohort of 616 female patients undergoing elective gynecologic surgery for benign or malignant conditions at a tertiary care academic medical center underwent a postoperative neurologic evaluation to identify postoperative neuropathy of the lower extremities.

RESULTS

Fourteen peripheral nerve injuries were observed in 11 patients, making the overall incidence of postoperative neuropathy 1.8% (95% confidence interval, 1.0-3.2). Injury to the lateral femoral cutaneous (5), femoral (5), common fibular (1), ilioinguinal/iliohypogastric (1), saphenous (1), and genitofemoral (1) nerves were detected. Complete resolution of neuropathic symptoms occurred in all but 1 patient (91%). Median time to resolution of symptoms was 31.5 days (range, 1 day to 6 months).

CONCLUSION

The incidence of lower extremity neuropathy attributable to gynecologic operations is low, and these neuropathies resolve in the great majority of cases.

Obturator mononeuropathy caused by lipomatosis of the nerve: a case report

We report a patient who presented with the clinical features of obturator mononeuropathy. Abdomino-pelvic computed tomography revealed a fusiform mass in the right perivesical space; magnetic resonance imaging (MRI) showed characteristic "coaxial-cable-like" appearance in cross-section and "spaghetti-like" appearance in longitudinal section, pathognomonic of lipomatosis of the nerve. Nerve lipomatosis as the cause of obturator neuropathy has not been previously reported. MRI provides definite and graphic proof of the diagnosis.

Obturator neuropathy

Obturator neuropathy is a difficult clinical problem to evaluate. One possible cause of pain is due to fascial entrapment of the nerve. Symptoms include medial thigh or groin pain, weakness with leg adduction, and sensory loss in the medial thigh of the affected side. Radiographic imaging provides limited diagnostic help. MRI may detect atrophy in the adductors of the leg. However, it is unable to detect any abnormality of the nerve or in the fibro-osseus tunnel. The best test for diagnosis is by electromyography (EMG) and can be confirmed by a local nerve block. Pharmacologic management of pain and physical therapy can be helpful in the acute phase of injury. Surgical decompression of the nerve should be considered for lesions documented by EMG or local nerve block, for those with predisposing risk factors (prior surgery, pelvic trauma, or hematoma) and with prolonged or severe lesions.

Ultrasound-guided steroid injection for obturator neuralgia

Obturator neuralgia (ON) presents with pain in the groin, medial thigh, and sometimes the medial aspect of the knee. The causes include trauma, obturator hernia, pelvic cancer, pelvic surgery, hip surgery, following pelvic fractures, endometriosis, retroperitoneal hematoma, pregnancy, and delivery. Ultrasound (US) guidance facilitates real-time imaging, identification of vascular structures, and improves patient comfort in situations where nerve stimulation can be unpleasant. This is a case report of ON successfully treated with US-guided steroid injection. A 55-year-old man was referred to the pain clinic with groin pain and allodynia in the medial thigh and knee following a fall. He had tried multiple other therapies and none of them provided significant relief. Using a 10-5-MHz multi-frequency, 38-mm linear array transducer, the obturator nerve was scanned in both longitudinal and transverse directions. Under real-time imaging 10 mg of medroxy-progesterone in a volume of 1 mL was injected. Following the injection, a small area of the medial side of knee was still tender to light touch. A second injection was placed inferiorly and provided pain relief for more than 5 months. This successful demonstration of US guidance in ON may further encourage US guidance in pain clinic interventions.

Obturator Nerve Entrapment

OBJECTIVE

Obturator neuralgia consists of pain radiating from the obturator nerve territory to the inner thigh.

METHODS

We report a case of idiopathic obturator neuralgia resulting from compression of the obturator nerve in the obturator canal, causing a case of nerve entrapment syndrome. The pain was characterized by its localization in the inguinal region and anterointernal side of the thigh, going down to the internal side of the knee. It was worse when standing or in a monopodal stance. Walking caused pain and a limp.

RESULTS

The diagnosis was confirmed by an analgesic block. The analgesic was infiltrated using a posterior approach and computer-assisted tomography, allowing the quality and specificity of the infiltration to be judged.

CONCLUSION

We describe, for the first time, a treatment of obturator neuralgia by a minimally invasive laparoscopic approach. This involved an obturator nerve neurolysis and section of the internal obturator muscle and the obturator membrane.

Neurosurgical treatment of perineal neuralgias

Perineal pain is the basis of presentation to different specialities. This pain is still rather unknown and leads the different teams to inappropriate treatments which may fail. For more than twenty years, we have seen these patients in a multidisciplinary consultation. Our anatomical works have provided a detailed knowledge of the nervous supply of the perineum which allowed us to propose the description of an entrapment syndrome of the pudendal nerve. Other disturbances of different origins were highlighted helping colleagues to a better analysis of this enigmatic painful syndrome. Cadaveric studies have been done to guide treatments by blocks and surgery if necessary according to well defined criteria. A randomized prospective study validated the surgery. The retrospective study concluded that two thirds of the patients improved after treatment. New anatomical concepts are leading us to enlarge the field of this type of surgery, with the hope of improving the success rate.

Obturator neuropathy complicating elective laparoscopic tubal occlusion

Isolated obturator neuropathy is rare. We report a woman who developed a severe obturator neuropathy from electrocautery during elective laparoscopic tubal ligation. This complication has not previously been described in association with the procedure, and the potential etiological role of an underrecognized anatomical variant, in which an accessory obturator nerve is present, is discussed.