Identification of the ilioinguinal and iliohypogastric nerves during open inguinal hernia repair: a nationwide register-based study

BACKGROUND

Chronic pain remains prevalent after open inguinal hernia repair and nerve-handling strategies are debated. Some guidelines suggest sparing nerves that are encountered; however, the nerve identification rates are unclear. This study aimed to investigate the nerve identification rates in a register-based nationwide cohort.

METHODS

This study was reported according to the RECORD guideline and used prospective, routinely collected data from the Danish Hernia Database, which was linked with the National Patient Registry. We included patients ≥ 18 years old, undergoing Lichtenstein hernia repair with information on nerve handling of the iliohypogastric and ilioinguinal nerves.

RESULTS

We included 30,911 open hernia repairs performed between 2012 and 2022. The ilioinguinal nerve was identified in 73% of the repairs and the iliohypogastric nerve in 66% of repairs. Both nerves were spared in more than 94% of cases where they were identified. Female patient sex, emergency and recurrence surgery, general anesthesia, medial and saddle hernias, and large defect size all result in lower nerve identification rates for both nerves.

CONCLUSION

The Ilioinguinal nerve was recognized in 73% of cases, while the iliohypogastric nerve was recognized in 66% with almost all identified nerves being spared during surgery. Several pre- and intraoperative factors influenced identification rates of the ilioinguinal and iliohypogastric nerve.

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.

Postmortem evaluation of neuromuscular damages more extensive than the surgical intervention area after iliac crest bone graft

Several complications may occur following iliac bone grafting, one of the common sites for autologous bone harvesting. Of these, it is difficult to localize the damage in neurological complications due to the presence of several nerves in a similar distribution area with variations among individuals. To minimize these complications, conventional clinical anatomical studies using normal human cadavers have estimated the theoretical neurological damage area corresponding to the surgical intervention area. We report a case of neuromuscular damage in a 93-year-old woman who had an iliac crest defect after a bone graft, based on the virtual and physical dissections with histological confirmations.In this study, the patient was confirmed to have severe neuromuscular complications with major complications including a hernia protruding through the iliac defect. One of the two ilioinguinal nerves was extracted with the hernia sac through the iliac defect, and its distal part was completely damaged. The iliohypogastric nerve, which was far from the defect foramen, also showed remarkable fibrosis and demyelination, affected by the degeneration of the transversus abdominis muscles.The present anatomical findings show that the area of eventual neuromuscular damage should be estimated to larger than the conventionally predicted area of direct nerve damage, which is usually concomitant with the surgical intervention area.

Is it possible to identify the inguinal nerves during hernioplasty? A systematic review of the literature and meta-analysis of cadaveric and surgical studies

Purpose

Patients who undergo inguinal hernioplasty may suffer from persistent postoperative pain due to inguinal nerve injuries. The aim of this systematic review and meta-analysis was to provide comprehensive data on the prevalence (identification rates), anatomical characteristics, and ethnic variations of the ilioinguinal (IIN), the iliohypogastric (IHN) and the genital branch of the genitofemoral (GNF) nerves.

Methods

The systematic literature search was conducted using the PubMed, Scopus and Web of Science databases.

Results

A total of 26 articles (5265 half-body examinations) were included in this study. The identification rate of the IIN was 94.4% (95% CI 89.5–97.9) using a random-effects model. Unweighted multiple regression analysis showed that study sample size (β = − 0.74, p = .036) was the only statistically significant predictor of lower prevalence. The identification rates of the IHN and GNF was 86.7% (95% CI 78.3%–93.3%) and 69.1% (95% CI 53.1%–83.0%) using a random-effects model, respectively. For those outcomes, a visual analysis of funnel and Doi plots indicated irregularity and provided evidence that larger studies tended to have lower identification rates. In terms of the synthesis of anatomical reference points, there was a large and statistically significant amount of heterogeneity for most outcomes.

Conclusions

The identification rates of the inguinal nerves in our study were lower than reported in literature. The lowest was found for GNF, suggesting that this nerve was the most difficult to identify. Knowledge regarding the anatomy of the inguinal nerves can facilitate their proper identification and reduce the risk of iatrogenic injury and postoperative pain.