Genitofemoral Research Articles

Ultrasound-guided microwave ablation in the treatment of inguinal neuralgia.

Chronic groin pain can be due to a variety of causes and is the most common complication of inguinal hernia repair surgery. The etiology of pain after inguinal hernia repair surgery is often multifactorial though injury to or scarring around the nerves in the operative region, namely the ilioinguinal nerve, genital branch of the genitofemoral nerve, and the iliohypogastric nerve, is thought to be a key factor in causing chronic post-operative hernia pain or inguinal neuralgia. Inguinal neuralgia is difficult to treat and requires a multidisciplinary approach. Radiologists play a key role in the management of these patients by providing accurate image-guided injections to alleviate patient symptoms and identify the pain generator. Recently, ultrasound-guided microwave ablation has emerged as a safe technique, capable of providing durable pain relief in the majority of patients with this difficult to treat condition. The objectives of this paper are to review the complex nerve anatomy of the groin, discuss diagnostic ultrasound-guided nerve injection and patient selection for nerve ablation, and illustrate the microwave ablation technique used at our institution.

Ultrasound guided ilioinguinal & iliohypogastric nerve blocks combined with genital branch of genitofemoral nerve block for open inguinal hernia repair

Ultrasound guided ilioinguinal & iliohypogastric nerve blocks combined with genital branch of genitofemoral nerve block for open inguinal hernia repair

Clinically Differentiated Abnormalities of the Architecture and Expression of Myosin Isoforms of the Human Cremaster Muscle in Cryptorchidism and Retractile Testis

Aim: To describe architecture and expression of myosin isoforms of the human cremaster muscle (CM) and to individuate changes in clinically differentiated abnormalities of testicular descent: cryptorchidism or undescended testis (UDT) and retractile testis (RT). Background: The CM is a nonsomitic striated muscle differentiating from mesenchyme of the gubernaculum testis. Morphofunctional and molecular peculiarities linked to its unique embryological origin are not yet completely defined. Its role in abnormalities of testicular descent is being investigated. Subjects and Methods: Biopsy samples were obtained from corrective surgery in cases of cryptorchidism, retractile testis, inguinal hernia, or hydrocele. Muscle specimens were processed for morphology, histochemistry, and immunohistology. Results and Conclusions: The CM differs from the skeletal muscles both for morphological and molecular characteristics. The presence of fascicles with different characterization and its myosinic pattern suggested that the CM could be included in the specialized muscle groups, such as the extrinsic ocular muscles (EOMs) and laryngeal and masticatory muscles. The embryological origin from the nonsomitic mesoderm is, also for the CM, the basis of distinct molecular pathways. In UDT, the histological alterations of CM are suggestive of denervation; the genitofemoral nerve and its molecular messengers directed to this muscle are likely defective. Compared with the other samples, RT has a distinct myosinic pattern; therefore, it has been considered a well-defined entity with respect to the other testicular descent abnormalities.

A study to improve identification of the retroperitoneal course of iliohypogastric, ilioinguinal, femorocutaneous and genitofemoral nerves during laparoscopic triple neurectomy.

Laparoscopic triple neurectomy is an available treatment option for chronic groin pain, but a poor working knowledge of the retroperitoneal neuroanatomy makes it an unsafe technique. Describe the retroperitoneal course of iliohypogastric, ilioinguinal, lateral femoral cutaneous and genitofemoral nerves, to guide the surgeon who operates in this region. Fifty adult cadavers were dissected resulting in 100 anatomic specimens. Additionally, 30 patients were operated for refractory chronic inguinal pain, using laparoscopic triple neurectomy. All operations and dissections were photographed. Measurements were made between the nerves of the lumbar plexus and various landmarks: interneural distances in a vertical midline plane, posterior or anterior iliac spine and branch presentation model. The ilioinguinal and iliohypogastric nerves were independent in 78% (Type II) and separated by an average of 2.5 ± 0.8cm. In surgery study, only 38% were recognized as Type II and at a significantly greater distance (3.5 ± 1.2cm, p < 0.001). The distance between ilioinguinal and lateral femoral cutaneous nerves was also greater during surgery, with statistical significance (5.1 ± 1.5 versus 4.2 ± 1.5, p < 0.005). The distance of the nerves to their bone references were not statistically different. The genitofemoral nerve emerged from the psoas major muscle in 20% as two separate branches (Type II), regardless of the study. The lateral femoral cutaneous nerve had a mean distance of 0.98 ± 1.6cm medial to the anterior superior iliac spine. The identification of the IH, II, FC and GF nerves is essential to reduce the rate of failures in the treatment of CGP. The frequent anatomical variations of the lumbar plexus nerves make knowledge of their courses in the retroperitoneal space essential to ensure safe surgery. The location of the nerves in the LTN is distorted by up to 1cm. regarding references in the cadavers.

Human cremaster muscle and cremasteric reflex: A comprehensive review

ObjectiveHuman research on the cremaster muscle (CM), cremasteric reflex (CMR) and genitofemoral nerve (GFN) and reports on their clinical applications using electrophysiological and histological techniques are rare. We aimed to present a detailed review of the human CM and CMR based on our earlier publications and relevant literature. MethodsElectromyography (EMG) of the CM was recorded using disposable needle electrodes. CMR was obtained with tactile and/or electrical stimulation of the inner thigh. Transcranial magnetic stimulation (TMS) and magnetic stimulation of the upper lumbar roots were applied; GFN was stimulated using a surface electrode at the anterior superior iliac spine. ResultsCM striated fibers comprised multiple motor end plates. CM needle EMG results were similar to those of the limb muscles in chronic neurogenic disorders. TMS produced clear-cut evoked motor responses from CM. GFN motor conduction time to CM was absent or delayed in patients with inguinal hernia. EMG of CM was abnormal in 40% of patients with premature ejaculation. ConclusionCM is different from other skeletal muscles both morphologically and physiologically. Intersegmental sacrolumbar reflexes are useful for evaluating ejaculatory dysfunction. SignificanceCM is an important muscle for testis thermoregulation and sexual reflexes. Neurophysiological techniques are available for physiological and clinical studies.

Vascularized Genitofemoral Nerve Flap Based on the Deep Branch of the Superficial Circumflex Iliac Artery

Vascularized Genitofemoral Nerve Flap Based on the Deep Branch of the Superficial Circumflex Iliac Artery

Retroperitoneal Approach for Ilioinguinal, Iliohypogastric, and Genitofemoral Neurectomies in the Treatment of Refractory Groin Pain After Inguinal Hernia Repair.

Inguinal hernia repair is one of the most commonly performed surgical procedures. Postoperative neuropathic groin pain is a potentially disabling complication and can be due to a neuroma of the ilioinguinal, iliohypogastric, and/or genitofemoral nerves. In this article, we present our operative technique-a retroperitoneal approach to the ipsilateral ilioinguinal, iliohypogastric, and genitofemoral nerves with neurectomy and proximal transposition of these nerves-for management of neuropathic pain. A retrospective review was performed of 12 of the patients who underwent this surgery at our institution. Three of 12 patients underwent a selective neurectomy, whereas 9 of 12 underwent a triple neurectomy; 3 of the 9 patients who underwent triple neurectomy also had a retroperitoneal peripheral nerve stimulator placed at the time of neurectomy. Pain visual analog scores (VASs) demonstrated significant improvement after neurectomy (preoperative pain VAS of 85 ± 11 vs postoperative pain VAS of 47 ± 32, P = 0.0027). Eight of 12 patients experienced partial or complete pain relief, whereas 4 of 12 patients had no pain relief. There were no major complications, and the minor complication rate was low for all patients and primarily related to peripheral nerve stimulator placement. This retroperitoneal approach to triple neurectomy for treatment of refractory groin pain in postoperative inguinal hernia repair patients is safe and effective for an otherwise devastating problem.

Surgical Release of the Adductor Longus With or Without Sports Hernia Repair Is a Useful Treatment for Recalcitrant Groin Strains in the Elite Athlete.

Background:Chronic strain and/or tendinopathy of the adductor longus tendon can be a cause of long-standing groin pain in the elite athlete, resulting in significant time lost from competition. Accurate diagnosis and treatment can expedite return to play.Purpose/Hypothesis:To evaluate return to sport and performance in National Collegiate Athletic Association (NCAA) Division I football players and National Football League (NFL) players following adductor longus release with or without sports hernia repair. We hypothesized that adductor release will be an effective method of treatment for recalcitrant groin/adductor pain in these athletes.Study Design:Case series; Level of evidence, 4.Methods:A cohort study was performed of all NFL players and NCAA Division I college athletes who had undergone an adductor longus tendon release with or without sports hernia repair by 1 of 2 fellowship-trained orthopaedic surgeons between May 1999 and January 2013. All patients reported groin pain below the inguinal ligament and localized to their adductor longus. Symptoms lasted longer than 10 weeks and limited their ability to effectively perform during sport, as assessed by their coach and self-assessment. Questionnaires were given to all 26 patients to assess long-term surgical outcomes. A subgroup analysis was performed for NFL players, in which “performance scores” were calculated according to individual player statistics while playing. Scores obtained before the diagnosis of chronic adductor longus tendinopathy or strain were compared with those after surgery. Patients with prior abdominal or pelvic surgery, radiographic evidence of degenerative joint disease of the hip, labral tears or femoral acetabular impingement, prostatic or urinary tract disease, or nerve entrapment of the ilioinguinal, genitofemoral, or lateral femoral cutaneous nerves were excluded from the study.Results:A total of 32 athletes underwent an adductor longus tenotomy during the study period. Of these patients, 28 were college- or professional-level athletes who underwent an adductor longus tenotomy, with a mean ± SD follow-up time of 6.2 ± 4.2 years (range, 12-178 months). Of the 32 patients, 20 had a concomitant sports hernia repair in addition to an adductor longus tenotomy. Thirty-one patients (97%) were able to return to their previous sport, and 30 (94%) were able to return at their previous level of play. Thirty patients (94%) reported that they were satisfied with their decision to have surgery. No player complained of weakness or a decrease in running speed or power. Mean return to play was 12 weeks from date of surgery. In the subgroup analysis of 16 NFL players, there were no statistically significant differences for the pre- versus postoperative comparisons of the athlete performance scores (P = .74) and the percentage of the games started versus played (P = .46). After separation of players who had a concomitant hernia repair from players who did not, there was no statistically significant difference in performance scores or percentages of games started.Conclusion:In this study of elite athletes, adductor longus tenotomy with or without a concomitant sports hernia repair provided overall acceptable and excellent results. Athletes were able to return to their previous level of athletic competition and performance with consistent relief of groin pain. Return to play in an NFL game averaged 12 weeks following surgery.

Coil-Eroded Left Ovarian Vein Presenting as Chronic Pelvic Pain and Genitofemoral Nerve Compression Syndrome

Chronic pelvic pain is a frequent health problem in women during childbearing age. The etiology of chronic pelvic pain includes irritable bowel syndrome, endometriosis, adenomyosis, pelvic congestion syndrome, urologic disorders, and psychosocial issues.

Bladder reinnervation by somatic nerve transfer to pelvic nerve vesical branches does not reinnervate the urethra.

AimsWe sought to determine whether somatic lumbar nerve transfer to the pelvic nerve's anterior vesical branch after sacral decentralization for detrusor muscle reinnervation also leads to aberrant innervation of the bladder outlet.MethodsTwenty‐six female mongrel hound dogs underwent transection of sacral dorsal and ventral spinal roots (ie, sacral decentralization). Immediately afterward, 12 received genitofemoral nerve transfer and 9 received femoral nerve branch transfer. Five were left sacrally decentralized. Controls included 3 sham‐operated and 6 unoperated. Eight months postsurgery, the bladder and urethra were injected with retrograde tracing dyes cystoscopically. After 3 weeks, detrusor and urethral pressures were assayed electrophysiologically immediately before euthanasia and characterization of neural reinnervation.ResultsElectrical stimulation of spinal cords or roots did not lead to increased urethral sphincter pressure in nerve transfer animals, compared with decentralized animals, confirming a lack of functional reinnervation of the bladder outlet. In contrast, mean detrusor pressure increased after lumbar cord/root stimulation. In sham/unoperated animals, urethral and bladder dye injections resulted in labeled neurons in sacral level neural structures (dorsal root ganglia [DRG], sympathetic trunk ganglia [STG], and spinal cord ventral horns); labeling absent in decentralized animals. Urethral dye injections did not result in labeling in lumbar or sacral level neural structures in either nerve transfer group while bladder dye injections lead to increased labeled neurons in lumbar level DRG, STG, and ventral horns, compared to sacrally decentralized animals.ConclusionPelvic nerve transfer for bladder reinnervation does not impact urethral sphincter innervation.

Genitofemoral Nerve Sparing Adhesiolysis

Video Objective The objective of this video is to review the anatomical landmarks, innervations and mechanisms of injury of the genitofemoral nerve in order to avoid its injury in cases with significant pelvic adhesions. Setting The patient is a thirty-two-year-old gravida three para three who is known for endometriosis. She previously underwent a caesarean hysterectomy for invasive placentation. She presented with chronic pelvic pain. She tried numerous medical treatments; only GnRH agonist controlled her pain. She was therefore consented for laparoscopic bilateral salpingo-oophorectomy which was performed at a tertiary care center by the minimally invasive gynecology surgery team. She had extensive abdominal and left pelvic side wall adhesions. In fact her left ovary was severely adherent onto the left external iliac artery and genitofemoral nerve. Interventions During the laparoscopic bilateral salpingo-oophorectomy, adhesiolysis and dissection near the genitofemoral nerve and external iliac artery were performed. Conclusion In the case of severe pelvic side wall adhesions and absence of a uterus, recognition of pelvic landmarks is of paramount importance. This facilitates identification of other pelvic structures and in this case, prevented injury to the external iliac artery and the genitofemoral nerve. Furthermore, careful tissue handling and dissection techniques are crucial. These help to maintain minimal blood loss, develop surgical planes and avoid injuries to pelvic structures.

Surgical Pelvic Neuroanatomy: An Overview of Commonly Encountered Nerves in Benign Gynecologic Surgeries and Safe Dissection Techniques

Video Objective A thorough understanding of the natural course and functions of the nerves in the pelvis is critical in complex benign gynecological surgery to avoid injury and morbidity to the patient. This video reviews how to locate and safely dissect common nerves found in the pelvis that may be encountered in complex gynecological cases. Setting Multiple patients at a large academic center with a robust team of minimally invasive gynecologic surgeons. Many patients have extensive adhesions or severe endometriosis. Interventions Multiple nerves, such as the superior hypogastric plexus, hypogastric nerves, pelvic splanchnic nerves, sacral nerve roots, and the genitofemoral nerves, are dissected out during the course of the surgery. Simple surgical techniques, such as traction-countertraction and blunt dissection are employed. Conclusion In complex gynecologic surgeries, the disease process may require extensive dissections in to the retroperitoneal spaces, where critical pelvic nerves are at risk for injury. With increased knowledge of the natural course of the nerves as well as having an array of dissection techniques, the surgeon can decrease the risk of inadvertent nerve injury and patient morbidity. If the disease is severely involved in areas where fragile nerves are, consideration needs to be given for a nerve preservation.

Surgical Management of Genitofemoral Neuralgia

Video Objective This video reviews the etiology, diagnosis, and management of genitofemoral neuralgia which is defined as pain along the distribution of the genitofemoral nerve. Setting The patient in this video began having symptoms of genitofemoral neuralgia following a laparotomy. A common mechanism of iatrogenic injury to this nerve is crush injury from poorly placed self-retaining retractors during abdominopelvic surgery. A neurectomy can be offered because the genitofemoral nerve has only sensory function and no motor function. Interventions We review the surgical technique for resection of the genital branch of the genitofemoral nerve. This technique involves retroperitoneal dissection over the psoas muscle, identification of the bifurcation of the nerve into its femoral and genital branches, isolation of the nerve, resection of the nerve, and implantation of the proximal nerve ending into the psoas muscle for nerve regeneration and neuroma prevention. Conclusion This technique is 66-100% in successful in relieving symptoms including the case of this patient.

2405 The Cult of the Occult Hernia and the Endometriosis Population

Study Objective Endometriosis is a condition in which tissue similar to but not the same as the lining of the uterus is found throughout the pelvic cavity. Pelvic Physical Therapy is a sub specialty of physical therapy focused on the hip, lower abdomen, and pelvis from the bones, to the muscles, including the pelvic floor, to the nerves and fascia. Ongoing pelvic pain post excision of endometriosis by a gynecology specialist may be treated by a pelvic physical therapist. In one year, a pelvic physical therapy practice specializing in endometriosis issues, multiple patients were suspected to have occult, or no bulge, hernias as sources of pelvic pain. The objective of this study is to examine in a retrospective analysis the impact of occult female hernia on pelvic pain post excision of endometriosis. Design Retrospective Analysis. Setting Outpatient Private Physical Therapy Practice specializing in endometriosis. Patients or Participants 35 Interventions Patients were evaluated based on nerve mapping and then were sent for MRI with a General Surgeon confirming presence of defect in the pre-peritoneal space. Measurements and Main Results In a one year period in a private physical therapy practice specializing primarily in endometriosis, out of 35 patients with endometriosis were screened for occult hernia's, no bulge hernias not seen within the retro-peritoneal space during excision of endometriosis, 22 were positive for nerve compressions onto either the ilioinguinal or genitofemoral nerves. Conclusion Occult hernia may contribute to pain during sex, genital pain, groin pain, pelvic floor pain, increased lower abdominal pain during menstruation, perceived urinary pressure and leg pain. In the patient with endometriosis hernia may be missed during follow-up visits and surgery with the gynecologist. As a driver in pelvic pain, occult hernia should become more widely recognized as a source of pelvic pain.

Evaluation of Ultrasound-guided Genitofemoral Nerve Block Combined with Ilioinguinal/iliohypogastric Nerve Block during Inguinal Hernia Repair in the Elderly.

To evaluate the anesthetic effect of ultrasound-guided (USG) ilioinguinal/iliohypogastric nerve (II/IHN) block combined with genital branch of genitofemoral nerve (GFN) block in the elderly undergoing inguinal hernia repair, 54 old patients (aged 60-96years, ASA I-III) with indirect hernia were enrolled and scheduled for unilateral tension-free herniorrhaphy. Patients were grouped randomly to receive either USG II/IHN plus GFN block (Group G) or USG II/IHN block alone (Group I). The intraoperative visual analogue scale (VAS) scores were recorded at skin incision, at spermatic cord/round ligament traction and at sac ligation. The resting and dynamic VAS scores were recorded postoperatively. The requirements of extra sedatives and analgesics for intra- and postoperative analgesia were assessed. Occurrence of complications of the block, postoperative nausea and vomiting and femoral nerve palsy was also reported. Both groups showed similar sensory block. When stretching spermatic cord/round ligament, the patients in group G had significantly lower VAS scores than in group I. And group G used much fewer adjuvant sedatives and analgesics to achieve adequate anaesthesia. In addition, group G was presented with better intraoperative anaesthesia and lower postoperative dynamic VAS scores at all time points tested. No significant difference was found in the postoperative requirement of rescue medication. Both groups showed no complications related to the block and group G reported no femoral nerve palsy. The addition of GFN block to II/IHN block improves the quality of perioperative anesthesia and analgesia in the elderly and reduces the consumption of extra sedatives and analgesics during the surgery.

A case report and review of lumbar hernia

The lumbar area is limited by the bone structures (superiorly by the 12th rib and inferiorly by the iliac crest); furthermore, several important nerves including the genitofemoral nerve, lateral femoral cutaneous nerve, ilioinguinal and iliohypogastric nerves are all exposed in this area after retroperitoneal dissection during lumbar hernia repair [1, 2], which render the risk and challenge for lumbar hernia repair and mesh fixation. In addition, the superior and inferior lumbar hernias, although had the same name of lumbar hernia, are quite different according to the anatomical location and there is no standard and preferred method for lumbar hernia repair. However, strangulated primary lumbar hernia, although rare, may occur in about 9% of cases, especially in elderly patients [3, 4].

The Effects of Transcutaneous Electrical Nerve Stimulation on Post-Episiotomy Pain Severity in Primiparous Women: A Randomized, Controlled, Placebo Clinical Trial.

Background: Episiotomy or cutting the perineum is the most common operation in obstetrics. Perineal pain is the main complication of episiotomy that affects the quality of life and mental health of the mother. Reducing the pain and side effects of the chemical drugs prescribed for pain relief has attracted the attention of both physicians and scientists. This study was conducted to determine the effects of transcutaneous electrical nerve stimulation (TENS), as an alternative method, on post-episiotomy pain severity. Materials and Methods: This randomized clinical trial was performed on 120 primiparous women who had referred to Sanandaj Besat Hospital in 2018. The patients were divided randomly into three groups, including the intervention group (TENS-On), the placebo group (TENS-Off), and the control group. TENS electrodes were placed near the episiotomy site in genitofemoral and pudendal nerves. The pain was measured after episiotomy in lying, sitting, and activity positions. The pain severity was measured using a pain measurement instrument (numeral rating score) at four-time points, i.e., before the intervention as well as 30, 60, and 120 minutes after the TENS intervention. For data analysis, Pearson correlation, student’s t-test, Kruskal-Wallis test, ANOVA test, and Mann-Whitney U tests were used. Results: Intragroup evaluation results for placebo and control groups demonstrated no significant difference in the pain score (P>0.05). A significant difference was observed between the mean pain severity of the intervention group and that of the group with walking activities (P=0.04). In terms of the intergroup evaluation, there was a significant difference observed between the mean pain severity of the lying position and that of the control group (P=0.008). Regarding the sitting position, no significant difference was observed between its mean pain severity and that of the other two groups (P=0.04). Conclusion: TENS is an effective and safe method for post-episiotomy pain relief and a routine method used in the obstetrics and gynecology ward.

The Effects of Transcutaneous Electrical Nerve Stimulation on Post-Episiotomy Pain Severity in Primiparous Women: A Randomized, Controlled, Placebo Clinical Trial

Background: Episiotomy or cutting the perineum is the most common operation in obstetrics. Perineal pain is the main complication of episiotomy that affects the quality of life and mental health of the mother. Reducing the pain and side effects of the chemical drugs prescribed for pain relief has attracted the attention of both physicians and scientists. This study was conducted to determine the effects of transcutaneous electrical nerve stimulation (TENS), as an alternative method, on post-episiotomy pain severity. Materials and Methods: This randomized clinical trial was performed on 120 primiparous women who had referred to Sanandaj Besat Hospital in 2018. The patients were divided randomly into three groups, including the intervention group (TENS-On), the placebo group (TENS-Off), and the control group. TENS electrodes were placed near the episiotomy site in genitofemoral and pudendal nerves. The pain was measured after episiotomy in lying, sitting, and activity positions. The pain severity was measured using a pain measurement instrument (numeral rating score) at four-time points, i.e., before the intervention as well as 30, 60, and 120 minutes after the TENS intervention. For data analysis, Pearson correlation, student’s t-test, Kruskal-Wallis test, ANOVA test, and Mann-Whitney U tests were used. Results: Intragroup evaluation results for placebo and control groups demonstrated no significant difference in the pain score (P&gt;0.05). A significant difference was observed between the mean pain severity of the intervention group and that of the group with walking activities (P=0.04). In terms of the intergroup evaluation, there was a significant difference observed between the mean pain severity of the lying position and that of the control group (P=0.008). Regarding the sitting position, no significant difference was observed between its mean pain severity and that of the other two groups (P=0.04). Conclusion: TENS is an effective and safe method for post-episiotomy pain relief and a routine method used in the obstetrics and gynecology ward. [GMJ.2019;8:e1404]Â

Surface Mapping of the Musculotendinous Attachments at the Pubic Symphysis in Cadaveric Specimens: Implications for the Treatment of Core Muscle Injury

To characterize the 3-dimensional muscular, musculotendinous, and neurovascular anatomy about the pubic symphysis relevant to core muscle injury (CMI). Ten cadaveric hips were dissected to characterize the musculotendinous insertion of the rectus abdominis and inguinal ligament, origins of the adductor longus and adductor brevis, and the pubic cartilage plate. A 3-dimensional coordinate measuring system and data acquisition software were used to calculate structure cross-sectional area, and the landmark anatomical relationships to 1 another and relevant neurovascular structures. All specimens were male with an average age of 62 ± 2years. The mean footprints of the rectus abdominis, inguinal ligament, adductor longus, and adductor brevis were 8.4 ± 3.1, 1.2 ± 0.5, 3.8 ± 1.6, and 2.9±1.3cm2, respectively. The mean pectineus and gracilis footprints were 6.3 ± 2.4 and 3.4 ± 0.9cm2, respectively. The mean cross-sectional area of the cartilage plate was 24.8 ± 5.6cm2. The adductor longus was an average 1.5 ± 0.25cm from the adductor brevis and 0.69 ± 0.52cm from the rectus abdominis. The genital branch of the genitofemoral nerve was an average of 4.3cm (range, 2.8-6.4) lateral to the insertion of the inguinal ligament. The femoral vein and artery were 3.0cm (range, 2.5-3.6) and 3.7cm (range, 2.5-5.9) lateral to the inguinal ligament footprint. The obturator nerve was 2.5cm (range, 1.6-3.4) lateral to the adductor longus. Familiarity with the anatomy of the pubic symphysis is essential for surgeons treating patients with CMI. We have shown that this relatively small area is the site of many muscular, musculotendinous, and neurovascular structures with various sized footprints and described the 3-dimensional anatomy of the anterior pubic symphysis. The origin of the adductor longus lies in close proximity to other structures, such as the adductor brevis, the insertion of the rectus abdominis, and the obturator nerve. These findings should be considered when operating in this region and treating patients with chronic groin pain. The anatomy of the pelvic region and pubic symphysis has not been well characterized. Intimate knowledge of relevant anatomy is essential to treating CMI, also known as athletic pubalgia or sports hernia.

High-Frequency (10 kHz) Electrical Stimulation of Peripheral Nerves for Treating Chronic Pain: A Double-Blind Trial of Presence vs Absence of Stimulation

The study objectives were to perform a clinical audit of patients implanted with 10 kHz spinal cord (SCS) and peripheral nerve (PNS) stimulators for treating chronic pain and to investigate the effect of 10 kHz PNS on pain and other sensory modalities in a double-blind cross-over trial. Pain, disability, and medication status were audited for 12 months after stimulator implantation in 58 SCS patients and in 11 PNS patients with an electrode positioned along a branch of the occipital or trigeminal nerve (four patients), a limb nerve trunk (four patients), or the S1 nerve root, genito-femoral nerve or ileo-inguinal nerve (one patient each). In PNS patients, pain and other sensory modalities were also assessed double-blind before and after the stimulator was switched either ON or OFF for two hours (protocol 1) or four hours (protocol 2). Decreases in pain and disability after stimulator implantation were maintained in both groups at 3-6 months, but these decreases were greater in PNS than SCS patients. In PNS trial patients, pain increased after the system had been turned OFF overnight for at least 12 hours before testing. Pain did not change after two hours of PNS but had decreased significantly after four hours. Other sensory modalities were minimally affected either by two or four hours of stimulation. These findings suggest that PNS at 10 kHz decreases pain when conducted for at least four hours. Stimulation analgesia does not appear to be due to sensory conduction block.