Position of lumbar plexus nerves in the psoas major: Application to transpsoas approaches to the lumbar spine

Far lateral interbody fusion is a minimally invasive operating technique. However, the incidence of postoperative neurological complications is high, and some scholars question its safety. This study describes the neuroanatomical features and spatial orientation within the psoas major. Ten embalmed male cadavers were selected and the left psoas major was dissected. Subsequently, the area between the anterior and the posterior edges of the vertebral body was divided into three equal zones. The nerves' distribution, number, and spatial orientation of the L1/2 to L4/5 intervertebral discs were examined. A caliper was used to measure the diameter of the nerve. The safety zone of the L1/2 intervertebral disc level is located in zone I and II, the relative safe zones of the L2/3 and L4/5 intervertebral discs are located in zone II, and the safety zone of the L3/4 intervertebral disc level is located in the caudal side of zone II. The genitofemoral nerve exits the psoas major in a co-trunk or two-branch pattern, and its exit point was distributed between the L3 and L4 vertebral bodies, mainly at the L3/4 intervertebral disc level. The sympathetic ganglia in the psoas major appeared only in zone I at the L2/3 intervertebral disc level. This is a systematic anatomical study that describes the nerves of the psoas major. Spine surgeons can use this study-which consists of important clinical implications-for preoperative planning, and thus, reduce the risk of nerve injury during surgery.

Groin pain of neurological origin as a differential diagnosis of femoroacetabular impingement

BACKGROUND

To describe the experience in the diagnostic process and treatment of patients with groin pain (GP) of neurological origin due to entrapment of the iliohypogastric (IH), ilioinguinal (IL) and genitofemoral (GF) nerves in a hip preservation clinic.

METHODS

Retrospective study of patients with GP of neurological origin confirmed with ultrasound-guided nerve block. Clinical outcomes were reported in 21 cases (age, 53.3 ± 15.9 years) treated with conservative treatment from January to December 2019, and in 9 patients (age 43.7 ± 14.6 years) who underwent neurectomy from January 2015 to December 2019. Pain intensity was assessed with a numerical rating scale (NRS) before starting the diagnostic process (Day 0) and at the end of follow-up.

RESULTS

All cases reported pain on groin palpation. Half of these cases also reported a positive FADIR test (flexion, adduction, internal rotation) (15/30). On day 0, the intensity of pain in cases treated with conservative treatment was severe in 19 patients (NRS 7-10) and moderate in 2 (NRS 4-6), with a median improvement of 7 points (interquartile range [IQR] 5.5-8.0) at the end of follow-up (p < 0.001). In neurectomy group, a similar improvement in pain severity was (Day 0: 9 points [IQR 8.0-9.0]; end of follow-up: 0 points [IQR: 0-2.0]; p = 0.002). At the end of the study, 17/21 patients with conservative treatment and 7/9 with neurectomy were pain free or with mild pain (NRS < 3).

CONCLUSIONS

In cases with PG of neurological origin, there is a high frequency of false positives in the FADIR test. Our findings suggest that neurectomy is a treatment option for patients in whom conservative treatment fails, providing significant pain relief.

Botulinum toxin type A for genitofemoral neuralgia: A case report

Genitofemoral neuralgia is an uncommon pain disorder that could be resistant to conventional treatment. A 78-year-old woman with refractory right genitofemoral neuralgia was treated with BoNT/A subcutaneous injections; the treatment was performed three times with significant pain improvement, although temporary, and without adverse events. BoNT/A may be a promising alternative intervention in the setting of genitofemoral neuralgia refractory to oral and/or topical treatment.

A Case Report on Spinal Neurostimulator Treatment for Painful Postsurgical Neuropathy of the Genitofemoral Nerve

Painful postsurgical neuropathy is an adverse event inherent to a wide variety of surgical treatments, so its diagnosis and specialized treatment are essential to maintaining the quality of life of the people who suffer from it. We present the case of a 31-year-old male with neuropathy of the genitofemoral nerve diagnosed by electromyography, resulting in intractable left testicular and thigh pain associated with a recent history of ipsilateral inguinal hernioplasty. After assessment by pain medicine and motor and sensory tests, a neurostimulator was placed in T8-T9 with action at the L1-L2 level, as well as a simultaneous electrode in S3, generating optimal pain relief and recovery of functionality.

Successful Resolution of Chronic Testicular Pain With an Impairment-Based Treatment Program: A Case Study With One-Year Follow-Up

Chronic testicular pain is a condition commonly experienced by males. Potential causes of testicular pain can be pathology localized within the testicle or referred pain from surrounding tissues or spinal conditions. The diagnostic differential is extensive and can be seen as a diagnosis of exclusion after structural disorders specific to the testicle are ruled out. In approximately 50% of the cases, the cause of pain is undetermined. Patients with testicular and inguinal pain may undergo extensive workup that overlooks potential neuropathic and musculoskeletal causes remote to the testicle. This case study describes the application of a conservative treatment program targeting presumptive chronic genitofemoral and/or ilioinguinal nerve entrapment along the course of the inguinal canal for the treatment of chronic testicular pain. By combining sacroiliac joint osteopathic manipulation, iliopsoas stretching, and soft tissue mobilization utilizing a vacuum suction cup, the patient was symptom-free on the fourth visit after suffering from testicular pain for a year. At a one-year follow-up, the patient remains pain-free.

Role of MR Neurography in Groin and Genital Pain: Ilioinguinal, Iliohypogastric, and Genitofemoral Neuralgia

OBJECTIVE

Chronic neuralgia of the border nerves (ilioinguinal, iliohypogastric, and genitofemoral) is difficult to diagnose and treat clinically. We examined the role of MR neurography (MRN) in the evaluation of border nerve abnormalities and the results of treatments directed at the MRN-detected nerve abnormalities.

MATERIALS AND METHODS

This retrospective cross-sectional study included 106 subjects with groin or genital pain (mean [± SD] age, 50.7 ± 15.4 years) who showed mono- or multifocal neuropathy of the border nerves at 3-T MRN. Subjects who underwent CT-guided perineural injection were assessed for pain response. Injection responses were categorized as positive, possible positive, and negative. Subjects who received hyaluronidase, continuous radiofrequency ablation, or surgery were also evaluated for treatment outcomes.

RESULTS

One hundred forty abnormal nerves were positive for neuropathy in 106 studies. Eighty of 106 subjects had single neuropathy, and 26 had multifocal neuropathy. Fifty-eight subjects underwent CT-guided perineural injections, with five receiving bilateral injections (63 injections). Improvement in subjective pain was seen in 53 of 63 cases (84.2%). A statistically significant improvement in pain response was noted in the isolated ilioinguinal nerve block group as compared with the isolated genitofemoral nerve block group (p = 0.0085). Thirteen of 58 subjects received multiple nerve injections at the same sitting. Both groups receiving single or multiple nerve injections had similar improvement in pain scores of 84% and 85%, respectively, although this difference was not statistically significant.

CONCLUSION

Our retrospective analysis showed improved pain relief in subjects who underwent CT-guided nerve blocks on the basis of a positive MRN.

Neurotrophin signaling in a genitofemoral nerve target organ during testicular descent in mice

BACKGROUND/AIM

It has been proposed that androgens control inguinoscrotal testicular descent via release of calcitonin gene-related peptide (CGRP) from a masculinised genitofemoral nerve (GFN). As there are androgen receptors in the inguinoscrotal fat pad (IFP) during the window of androgen sensitivity (E14-17 in mouse embryos), we tested the hypothesis that neurotrophins in the IFP may masculinise the sensory fibers of the GFN supplying the gubernaculum and IFP prior to gubernacular migration.

METHODS

Androgen-receptor knockout (ARKO) and wild-type (WT) mouse embryos were collected at E17, with ethical approval (AEC 734). Sagittal sections of IFP, mammary area and bulbocavernosus (BC) muscle were processed for standard histology and fluorescent immunohistochemistry for ciliary neurotrophic factor (CNTF), ciliary neurotrophic factor receptor (CNTFR) and cell nuclei (DAPI).

RESULTS

In the ARKO mouse CNTFR immunoreactivity (CNTFR-IR) was increased in the IFP but decreased in BC. Perinuclear staining of CNTF-IR was seen in mouse sciatic nerve but only weakly in IFP. In the mammary area, also supplied by GFN, there were no differences in IR staining.

CONCLUSION

This study found CNTFR-IR in the IFP was negatively regulated by androgen, suggesting that CNTF signaling may be suppressed in GFN sensory nerves to enable CGRP expression for regulating gubernacular migration in the male, but not the female. The indirect action of androgen via the GFN required for testicular descent may be one of the sites of anomalies in the putative multifactorial cause of cryptorchidism.

Genitofemoral neuralgia: adding to the burden of chronic vulvar pain

The vulva is a particularly common locus of chronic pain with neuropathic characteristics that occurs in women of any age, though most women with neuropathic type chronic vulvar pain will remain undiagnosed even following multiple physician visits. Here, we report on an exemplary case of a middle-aged woman who was referred to the Vulvovaginal Disease Clinic with debilitating vulvar burning and itching over the right labium majus that had been persisting for 2 years and was considered intractable. Careful history taking and clinical examination, followed by electrophysiological assessment through somatosensory evoked potentials was consistent with genitofemoral neuralgia, for which no obvious cause could be identified. Adequate pain relief was obtained with a serotonin–noradrenaline reuptake inhibitor and topical gabapentin cream. We briefly discuss the epidemiology, diagnosis, and treatment of genitofemoral neuralgia and provide a series of clues to guide clinicians in obtaining a presumptive diagnosis of specific neuropathic pain syndromes that may underlie chronic vulvar pain. We further aim to draw attention to the tremendous burden of chronic, unrecognized vulvar pain.

Reductions in calcitonin gene-related peptide may be associated with the impairment of the contralateral testis in unilateral cryptorchidism

The aim of the present study was to investigate the mechanism underlying the impairment of the contralateral testis in unilateral cryptorchidism in experimental rats using a molecular neurophysiological approach. Thirty-six male rats (21 days old) were divided into a cryptorchidism group, a cryptorchidism with division of the genitofemoral nerve (GFN) group and a control group (n=12/group). The distribution of the calcitonin gene-related peptide (CGRP) immunoreactive nerve fibers in the testes was studied using an immunohistochemistry technique. Germ cell apoptosis was detected using the terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling method. The concentration of malondialdehyde (MDA) in the testis tissue was evaluated using a spectrophotometric determination method, and the ultrastructure of Sertoli cells was observed using transmission electron microscopy. It was found that, 100 days after the surgery, the concentration of CGRP in the cryptorchidism group was decreased significantly, whereas the levels of MDA and the number of apoptotic germ cells were increased significantly compared with the control group (P<0.01). Following the division of the GFN, the damaging effects were decreased (P<0.01). The impairment mechanism may therefore be associated with a reduction in the level of CGRP in the contralateral testis. The reflex decrease in CGRP may be caused by germ cell apoptosis, decreased blood flow and oxygen levels, and the increase in reactive oxygen free radicals and lipid peroxidation.

Anatomical study of the iliohypogastric, ilioinguinal, and genitofemoral nerves using high-resolution ultrasound

INTRODUCTION

In this study we aimed to determine whether high-resolution ultrasound (US) can identify the iliohypogastric (IH), ilioinguinal (II), and genitofemoral (GF) nerves and their relations.

METHODS

This investigation, initially undertaken in cadavers, was followed by a high-resolution US study in 30 healthy adult volunteers (180 nerves) by 2 musculoskeletal radiologists on separate occasions, using 2 different approaches (proximal to distal and distal to proximal). A 0-3 scale was used to assess nerve visibility. Location and course of the IH, II, and GF nerves and their relations to adjacent anatomical structures were analyzed.

RESULTS

Nerves and their terminal branches were better visualized with the distal-to-proximal approach (P < 0.05). Visualization of the terminal branches was possible in up to 60% of volunteers.

CONCLUSIONS

High-resolution ultrasound (US) can identify the IH, II, and GF nerves at the level of the abdominal wall and the terminal branches in the majority of volunteers.

Anatomic relationships of psoas muscle: clinical applications to psoas hitch ureteral reimplantation

OBJECTIVE

The objective of the study was to examine the anatomic relationship of the genitofemoral and femoral nerves to the psoas major muscle.

STUDY DESIGN

Dissections were performed in 17 unembalmed female cadavers. Point A was used as the approximate location for placement of psoas hitch sutures and as the reference point from which all measurements were taken. Measurements included the width of the psoas major muscle, psoas minor tendon, genitofemoral nerve branches, and femoral nerve. The relative location of the genitofemoral and femoral nerves to point A and the presence or absence of a psoas minor tendon were documented.

RESULTS

The psoas minor tendon was absent on at least 1 side in 11 specimens (64.7%). The median width of the psoas minor tendon was 7 mm (range, 3-11.5 mm). The median width and depth of the psoas major muscle was 21.5 mm (range, 10-35 mm) and 20.0 mm (range, 11.5-32 mm), respectively. The median width of the genitofemoral nerve was 2 mm (range, 1-4.5 mm) and that of the femoral nerve was 6.3 mm (range, 5-10.5 mm). Overall, 54 genitofemoral nerve branches were identified in 17 cadavers, 30 medial (55.5%), 22 lateral (40.7%), and 2 directly overlying point A (3.7%).

CONCLUSION

The exact location for the placement of the psoas hitch sutures will vary, depending on the location of the ureteral injury and the anatomy of the psoas muscle and surrounding structures. A thorough understanding of this regional anatomy should optimize the placement of psoas hitch sutures during ureteral reimplantation procedures and help avoid nerve and vessel injury.

Ultrasound-guided pain interventions - a review of techniques for peripheral nerves

Ultrasound has emerged to become a commonly used modality in the performance of chronic pain interventions. It allows direct visualization of tissue structure while allowing real time guidance of needle placement and medication administration. Ultrasound is a relatively affordable imaging tool and does not subject the practitioner or patient to radiation exposure. This review focuses on the anatomy and sonoanatomy of peripheral non-axial structures commonly involved in chronic pain conditions including the stellate ganglion, suprascapular, ilioinguinal, iliohypogastric, genitofemoral and lateral femoral cutaneous nerves. Additionally, the review discusses ultrasound guided intervention techniques applicable to these structures.

Infertility in rats subjected to genitofemoral nerve section is not associated with testicular damage

This work was aimed at assessing the relationship between testicular ascent and infertility induced by genitofemoral nerve (GFN) section in rats. Eighteen male rats were assigned to three experimental groups as follows: (i) Group SGFN was subjected to surgical section of genitofemoral nerve; (ii) Group Sham; (iii) Control group. The GFN was cut at puberty (28D), and the contralateral testis removed at 90D, with fertility tests at 120D. At 150D, maturity index, epithelial area and histopathological index of seminiferous tubules of all rats were determined and statistically compared between superior and inferior testicle poles, and between groups. There were no differences in testicular parameters, sperm morphology or sperm concentrations (P > 0.05). Section of NGF interfered with fertility (58.3 ± 15.4 in SGFN versus 83.3 ± 10.5 in Sham) and litter size (6.2 ± 1.1 in SGFN versus 10.7 ± 1.4 in Sham). Cremaster of SGFN group showed early neuropathy. The GFN section induced partial testicular ascent and diminished fertility without damage on testicular morphology or spermatic parameters, because, cremaster could affect the contractibility and ejaculation mechanisms in which it participates. The study of the damage on cremaster induced by an injury on GFN could have an overview of the mechanisms inherent in the testicular ascent induced by this iatrogenic alteration and their potential risks on fertility.

The role of the gubernaculum in the descent and undescent of the testis

Testicular descent to the scrotum involves complex anatomical rearrangements and hormonal regulation. The gubernaculum remains the key structure, undergoing the 'swelling reaction' in the transabdominal phase, and actively migrating out of the abdominal wall to the scrotum in the inguinoscrotal phase. Insulin-like hormone 3 (Insl3) is the primary regulator of the first phase, possibly augmented by Müllerian inhibiting substance/anitmüllerian hormone (MIS/AMH), and regression of the cranial suspensory ligament by testosterone. The inguinoscrotal phase is controlled by androgens acting both directly on the gubernaculum and indirectly via the genitofemoral nerve, and release of calcitonin gene-related peptide from its sensory fibres. Outgrowth of the gubernaculum and elongation to the scrotum has many similarities to an embryonic limb bud.Cryptorchidism occurs because of both failure of migration congenitally, and failure of elongation of the spermatic cord postnatally. Germ cell development postnatally is disturbed in congenital cryptorchidism, but our current understanding of germ cell biology suggests that early orchidopexy, around 6 months of age, should provide a significant improvement in prognosis compared with a previous generation. Hormone treatment is not currently recommended. Acquired cryptorchid testes may need orchidopexy once they no longer reach the scrotum, although this remains controversial.