Anatomical basis of neuropathies and damage to the ilioinguinal nerve during repairs of groin hernias. (about 100 dissections)

Anatomical Variations of the Iliohypogastric Nerve: A Systematic Review of the Literature

Several anatomical variations of the iliohypogastric nerve branches have been observed in earlier studies. Knowledge of these variations is useful for the improvement of peripheral nerve blocks and avoidance of iatrogenic nerve injuries during surgeries. The purpose of this study was to perform a systematic review of the literature about the anatomical topography and variations of the iliohypogastric nerve. An extensive search on PubMed, Scopus, and Web of Science electronic databases was conducted by the first author in November 2021, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Anatomical or cadaveric studies about the origin, the course, and the distribution of the iliohypogastric nerve were included in this review. Thirty cadaveric studies were included for qualitative analysis. Several anatomical variations of the iliohypogastric nerve were depicted including its general properties, its origin, its branching patterns, its course, its relation to anatomical landmarks, and its termination. Among them, the absence of the iliohypogastric nerve ranged from 0 to 34%, its origin from L1 ranged from 62.5 to 96.5%, and its isolated emergence from psoas major ranged from 47 to 94.5%. Numerous anatomical variations of the iliohypogastric nerve exist but are not commonly cited in classic anatomical textbooks. The branches of the iliohypogastric nerve may be damaged during spinal anesthesia and surgical procedures in the lower abdominal region. Therefore, a better understanding of the regional anatomy and its variations is of vital importance for the prevention of iliohypogastric nerve injuries.

Fascinating history of groin hernias: Comprehensive recognition of anatomy, classic considerations for herniorrhaphy, and current controversies in hernioplasty

Groin hernias include indirect inguinal, direct inguinal, femoral, obturator, and supravesical hernias. Here, we summarize historical turning points, anatomical recognition and surgical repairs. Groin hernias have a fascinating history in the fields of anatomy and surgery. The concept of tension-free repair is generally accepted among clinicians. Surgical repair with mesh is categorized as hernioplasty, while classic repair without mesh is considered herniorrhaphy. Although various surgical approaches have been developed, the surgical technique should be carefully chosen for each patient. Regarding as interesting history, crucial anatomy and important surgeries in the field of groin hernia, we here summarized them in detail, respectively. Points of debate are also reviewed; important points are shown using illustrations and schemas. We hope this systematic review is surgical guide for general surgeons including residents. Both a skillful technique and anatomical knowledge are indispensable for successful hernia surgery in the groin.

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

BACKGROUND

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.

OBJECT

Describe the retroperitoneal course of iliohypogastric, ilioinguinal, lateral femoral cutaneous and genitofemoral nerves, to guide the surgeon who operates in this region.

METHODS

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.

RESULTS

The ilioinguinal and iliohypogastric nerves were independent in 78% (Type II) and separated by an average of 2.5 ± 0.8 cm. In surgery study, only 38% were recognized as Type II and at a significantly greater distance (3.5 ± 1.2 cm, 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 ± 1.6 cm medial to the anterior superior iliac spine.

CONCLUSION

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 1 cm. regarding references in the cadavers.

Incidence of chronic groin pain following open mesh inguinal hernia repair, and effect of elective division of the ilioinguinal nerve: meta-analysis of randomized controlled trials

PURPOSE

Chronic post-operative groin pain is a substantial complication following open mesh inguinal hernia repair. The exact cause of this pain is still unclear, but entrapment or trauma of the ilioinguinal nerve may have a role to play. Elective division of this nerve during hernia repair has been proposed in an attempt to reduce the incidence of chronic groin pain.

METHODS

We performed a meta-analysis of nine randomized controlled trials comparing preservation versus elective division of the ilioinguinal nerve during this operation.

RESULTS

A substantial proportion of patients having open mesh inguinal hernia repair experience chronic groin pain when the ilioinguinal nerve is preserved (estimated rate of 9.4% at 6 months and 4.8% at 1 year). Elective division of the nerve resulted in a significant reduction of groin pain at 6-months post-surgery (RR 0.47, p = 0.02), including moderate/severe pain (RR 0.57, p = 0.01). However, division of the nerve also resulted in an increase of subjective groin numbness at this time point (RR 1.55, p = 0.06). At 12-month post-surgery, the beneficial effect of nerve division on chronic pain was reduced, with no significant difference in the rates of overall groin pain (RR 0.69, p = 0.38), or of moderate-to-severe groin pain (RR 0.99, p = 0.98) between the two groups. The prevalence of groin numbness was also similar between the two groups at 12-month post-surgery (RR 0.79, p = 0.48).

CONCLUSIONS

Routine elective division of the ilioinguinal nerve during open mesh inguinal hernia repair does not significantly reduce chronic groin pain beyond 6 months, and may result in increased rates of groin numbness, especially in the first 6-months post-surgery.

Pain and compression neuropathy in primary inguinal hernia

PURPOSE

Enlargement of the ilioinguinal nerve at the external inguinal ring is observed in 34% of patients undergoing primary open inguinal herniorrhaphy; in 88% of patients it occurs at the fascial edge where the hernia mushrooms with abdominal pressure. Compression neuropathy occurs near many anatomical nerve constriction sites and is associated with enlargement of the peripheral nerve accompanied by sensory changes.

METHODS

In this prospective study, Carolina Comfort Scale (CCS) questionnaire data was collected for 35 primary hernia repairs. Each patient underwent primary inguinal herniorrhaphy that included ilioinguinal neurectomy. All nerves were sampled proximal to the external inguinal ring. Any nerves with grossly increased overall diameter to any degree distal to the external ring were additionally sampled in the thickened portions. A neuropathologist performed histologic evaluation of the H&E-stained cross sections.

RESULTS

Paired comparison of proximal and distal nerves revealed a greater overall diameter and greater measured nerve-specific diameter in distal nerve segments. Nerves with increased overall diameter were also found to have a statistically significant positive correlation with four of eight pain measures. Additionally, increased nerve-specific diameter correlates with increased pain on four of eight pain values, but age effect on nerve diameter blunts this finding.

CONCLUSIONS

Increased preoperative CCS pain values in primary open inguinal hernia are significantly correlated with gross enlargement of the overall diameter and nerve-specific diameter of the ilioinguinal nerve beyond the external inguinal ring. This is consistent with a compression neuropathy.

Wide resection of inguinal nerves versus simple section to prevent postoperative pain after prosthetic inguinal hernioplasty: our experience

BACKGROUND

In the literature, chronic groin pain (i.e. lasting >3 months) occurs in about 10 % of patients who undergo inguinal hernioplasty with prosthesis; it is characterized by a broad range of symptoms, and is relative to individual perceptions of pain. In 2-5 % of cases, the painful symptomatology is so intense that it interferes with daily activities, and can be debilitating in 0.5-6 % of cases. The best known cause of inguinodynia is neuropathy, due to implication of one or more inguinal nerves (iliohypogastric, ilioinguinal, and genitofemoral nerves) into fibroblastic processes; or from nervous stimulation caused by prosthetic material on adjacent nervous trunks. Many therapeutic strategies have been proposed to treat chronic groin pain, including intra-operative prophylactic neurectomy.

OBJECTIVE

The purpose of our study was to perform a comparative analysis between outcomes from wide resections of inguinal nerves versus those from simple nervous section (or minimal resection).

PATIENTS AND METHODS

We considered 350 patients who had undergone inguinal prosthetic hernioplasty with Trabucco's technique between 2004 and 2010. Wide nervous resection (removal of nerve segments 3-8 cm in length) was performed in 180. The other 170 patients underwent simple section or minimal resection. All patients were checked 1 week, 1 month, and 1 year after surgery.

RESULTS

Group 1: At 1-week follow-up, 63 patients (35 %) reported no pain, 113 (63 %) reported moderate pain, and 4 (2 %) intense pain; 1 month after the procedure, 152 patients (84.4 %) reported no pain, 25 (14 %) complained of moderate pain, and 3 (1.6 %) of severe pain; 1 year after surgery, only 1 patient (0.5 %) complained of constant pain. Group 2: At 1 week follow-up, 48 patients (28 %) reported no pain, 101 (59 %) reported moderate pain, and 21 (13 %) intense pain; 1 month after the procedure, 81 patients (47.6 %) had no pain, 72 (42.4 %) complained of moderate pain, and 17 (10 %) of severe pain; 1 year after surgery, 11 patients (6.5 %) had constant pain, and two of them were re-admitted for surgery. The lower incidence of chronic pain after long nervous resection is statistically significant (0.5 vs. 6.5 %; p = 0.006); the incidence of moderate pain 1 month after operation is also lower (14 vs. 42.4 %; p < 0.0001); patients who underwent a long resection experienced faster resolution of pain symptomatology, during a month. Also noteworthy is the lower incidence of intense pain in the short and medium term (after 1 week, 13 vs. 2 %, p = 0.0005; after 1 month, 10 vs. 1.6 %, p = 0.0018).

CONCLUSIONS

The prophylactic wide resection of selected segments of inguinal nerves, despite the apparent paradox of greater tissue damage, appears more effective than simple section at preventing postoperative inguinodynia, given both the lower incidence and the faster resolution of painful symptomatology.

Restoring tactile and erogenous penile sensation in low-spinal-lesion patients: procedural and technical aspects following 43 TOMAX nerve transfer procedures

BACKGROUND

The "TOMAX" (TO MAX-imize sensation, sexuality, and quality of life) procedure restores genital sensation in men with low spinal lesions, improving sexual health, as shown previously. It connects the dorsal nerve of the penis to the intact ipsilateral ilioinguinal nerve, unilaterally or bilaterally. This study reports on the technical aspects based on 43 TOMAX nerve transfers.

METHODS

In 40 patients with no penile but intact groin sensation, 43 nerve transfers were performed. Data on patient selection, surgical history, anatomy of the ilioinguinal nerve and dorsal nerve of the penis, unilateral or bilateral surgery, surgical technique, complications, and patient information were collected prospectively.

RESULTS

Regardless of origin, all patients with no penile but good groin sensation are eligible for the procedure, provided the ilioinguinal nerve is not damaged because of former inguinal surgery or absent because of anatomical variations. Selection of a unilateral or bilateral procedure depends on the presence or absence of reflex erections and bulbocavernosus reflex. Preliminary experience with the first three bilateral cases shows that it is technically feasible, with encouraging results. The surgical technique has evolved (described in detail, including video) to enhance outcome and reduce complications. Patients are better informed, resulting in realistic expectations.

CONCLUSIONS

This article synthesizes the procedural and technical experience of 43 TOMAX nerve transfers. Anyone skilled in peripheral nerve surgery and microsurgery can adopt this concept and further develop it. The TOMAX procedure can then be used to restore erogenous penile sensation and improve the quality of sexual health in patients with absent penile but good groin sensation.

Does nerve identification during open inguinal herniorrhaphy reduce the risk of nerve damage and persistent pain?

PURPOSE

Nerve identification during open inguinal hernia herniorrhaphy has been suggested as one of the factors that may reduce the risk of development of persistent postherniorrhaphy pain. In this prospective study, we evaluated whether intraoperative inguinal nerve identification influenced the risk of development of persistent postherniorrhaphy pain, sensory dysfunction in the groin and functional ability score after open hernia repair.

METHODS

A total of 244 men with a primary inguinal hernia underwent open Lichtenstein repair in a high-volume hernia surgery centre, where information on inguinal nerve identification was registered during operation. Before the operation and 6 months postoperatively, functional pain-related impairment was assessed with Activities Assessment Scale and pain intensity scores with Numeric Rating Scale (NRS 0-10). Quantitative sensory testing in the groin was performed before operation and 6 months postoperatively, in order to investigate intraoperative inguinal nerve damage.

RESULTS

The intraoperative nerve identification rates for the iliohypogastric, ilioinguinal and genitofemoral nerves were 94.7, 97.5 and 21.3 %, respectively. Thirty-nine patients (16.0 %) had substantial pain-related functional impairment at 6 months follow-up. There was no difference in risk of development of substantial pain-related functional impairment in patients with identification compared with non-identification of the iliohypogastric nerve (P = 1.0), the ilioinguinal nerve (P = 0.59), the genitofemoral nerve (P = 0.40) or all nerves (P = 0.52). There were no differences in regard to sensory loss in the groin area or in regard to improvement in functional outcome following surgery, between patients with and without nerve identification.

CONCLUSIONS

Although intraoperative inguinal nerve identification should be aimed at, other factors may contribute to the risk of nerve damage and persistent pain after open groin hernia repair.

A new method of spermatic cord mobilization in herniorrhaphy

Spermatic cord mobilization is a routine part of inguinal hernia repair, but the method of cord mobilization varies among surgeons. This study establishes an anatomic plane for spermatic cord mobilization. We studied the anatomy of the superficial cremasteric fascia in 105 male patients during herniorrhaphy for primary inguinal hernias. The mean patient age was 44.8 (18-71) years and mean body mass index was 24.1 kg/m(2) (21.5-27.1 kg/m(2)). The two layers of the superficial cremasteric fascia between the spermatic cord and the inguinal falx were incised to mobilize the cord. We found that spermatic cord mobilization during herniorrhaphy can be easily approached through an anatomic plane between the spermatic cord and the conjoined tendon with subsequent division of the superficial cremasteric fascia. None of the patients experienced any hemorrhage or nerve injury during cord mobilization. We found this method to be both safe and easy to learn.

International guidelines for prevention and management of post-operative chronic pain following inguinal hernia surgery

PURPOSE

To provide uniform terminology and definition of post-herniorrhaphy groin chronic pain. To give guidelines to the scientific community concerning the prevention and the treatment of chronic groin and testicular pain.

METHODS

A group of nine experts in hernia surgery was created in 2007. The group set up six clinical questions and continued to work on the answers, according to evidence-based literature. In 2008, an International Consensus Conference was held in Rome with the working group, with an audience of 200 participants, with a view to reaching a consensus for each question.

RESULTS

A consensus was reached regarding a definition of chronic groin pain. The recommendation was to identify and preserve all three inguinal nerves during open inguinal hernia repair to reduce the risk of chronic groin pain. Likewise, elective resection of a suspected injured nerve was recommended. There was no recommendation for a procedure on the resected nerve ending and no recommendation for using glue during hernia repair. Surgical treatment (including all three nerves) should be suggested for patients who do not respond to no-surgery pain-management treatment; it is advisable to wait at least 1 year from the previous herniorraphy.

CONCLUSION

The consensus reached on some open questions in the field of post-herniorrhaphy chronic pain may help to better analyze and compare studies, avoid sending erroneous messages to the scientific community, and provide some guidelines for the prevention and treatment of post-herniorraphy chronic pain.

What's new in the diagnosis and treatment of peripheral nerve entrapment neuropathies

Entrapment neuropathies can be common conditions with the potential to cause significant disability. Correct diagnosis is essential for proper management. This article is a review of recent developments related to diagnosis and treatment of various common and uncommon nerve entrapment disorders. When combined with classical peripheral nerve examination techniques, innovations in imaging modalities have led to more reliable diagnoses. Moreover, innovations in conservative and surgical techniques have been controversial as to their effects on patient outcome, but randomized controlled trials have provided important information regarding common operative techniques. Treatment strategies for painful peripheral neuropathies are also reviewed.

Anatomy of the ilioinguinal and iliohypogastric nerves with observations of their spinal nerve contributions

Proper anesthesia and knowledge of the anatomical location of the iliohypogastric and ilioinguinal nerves is important during hernia repair and other surgical procedures. Surgical complications have also implicated these nerves, emphasizing the importance of the development of a clear topographical map for use in their identification. The aim of this study was to explore anatomical variations in the iliohypogastric and ilioinguinal nerves and relate this information to clinical situations. One hundred adult formalin fixed cadavers were dissected resulting in 200 iliohypogastric and ilioinguinal nerve specimens. Each nerve was analyzed for spinal nerve contribution and classified accordingly. All nerves were documented where they entered the abdominal wall with this point being measured in relation to the anterior superior iliac spine (ASIS). The linear course of each nerve was followed, and its lateral distance from the midline at termination was measured. The ilioinguinal nerve originated from L1 in 130 specimens (65%), from T12 and L1 in 28 (14%), from L1 and L2 in 22 (11%), and from L2 and L3 in 20 (10%). The nerve entered the abdominal wall 2.8 ± 1.1 cm medial and 4 ± 1.2 cm inferior to the ASIS and terminated 3 ± 0.5 cm lateral to the midline. The iliohypogastric nerve originated from T12 on 14 sides (7%), from T12 and L1 in 28 (14%), from L1 in 20 (10%), and from T11 and T12 in 12 (6%). The nerve entered the abdominal wall 2.8 ± 1.3 cm medial and 1.4 ± 1.2 cm inferior to the ASIS and terminated 4 ± 1.3 cm lateral to the midline. For both nerves, the distance between the ASIS and the midline was 12.2 ± 1.1 cm. To reduce nerve damage and provide sufficient anesthetic for nerve block during surgical procedures, the precise anatomical location and spinal nerve contributions of the iliohypogastric and ilioinguinal nerves need to be considered.