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

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.

Sutureless Repair for Open Treatment of Inguinal Hernia: Three Techniques in Comparison

Currently, groin hernia repair is mostly performed with application of mesh prostheses fixed with or without suture. However, views on safety and efficacy of different surgical approaches are still partly discordant. In this multicentre retrospective study, three sutureless procedures, i.e., mesh fixation with glue, application of self-gripping mesh, and Trabucco's technique, were compared in 1034 patients with primary unilateral non-complicated inguinal hernia subjected to open anterior surgery. Patient-related features, comorbidities, and drugs potentially affecting the intervention outcomes were also examined. The incidence of postoperative complications, acute and chronic pain, and time until discharge were assessed. A multivariate logistic regression was used to compare the odds ratio of the surgical techniques adjusting for other risk factors. The application of standard/heavy mesh, performed in the Trabucco's technique, was found to significantly increase the odds ratio of hematomas (p = 0.014) and, most notably, of acute postoperative pain (p < 0.001). Among the clinical parameters, antithrombotic therapy and large hernia size were independent risk factors for hematomas and longer hospital stay, whilst small hernias were an independent predictor of pain. Overall, our findings suggest that the Trabucco's technique should not be preferred in patients with a large hernia and on antithrombotic therapy.

Nerve identification during open inguinal hernia repair: a systematic review and meta-analyses

PURPOSE

Inguinal hernia repair is one of the most common operations worldwide and despite this, the incidence of chronic pain remains high after inguinal hernia repair. The optimal nerve handling strategy is controversial and the rate at which nerves are identified remains uncertain. This study aimed to determine the identification rates of the ilioinguinal, iliohypogastric, and genitofemoral nerves as well as nerve handling strategies.

METHODS

This review was registered on PROSPERO (CRD 42023416576). PubMed, Embase, and Cochrane Central were systematically searched. Studies with more than 10 patients were included if they reported an identification rate for at least one of the nerves during elective open inguinal hernia repair in adults. Studies requiring nerve identification in their study design were excluded. Bias was assessed with the JBI critical appraisal tool and Cochrane's RoB-2 tool. The overall estimate of the prevalence was analysed with prevalence meta-analyses.

RESULTS

A total of 23 studies were included. The meta-analyses included 18 studies, which resulted in an identification rate of 82% (95% CI: 76-87%) for the ilioinguinal nerve, 62% (95% CI: 54-71%) for the iliohypogastric nerve, and 41% (95% CI: 27-55%) for the genitofemoral nerve. Nerves were spared in 82% of all repairs.

CONCLUSION

The ilioinguinal, iliohypogastric, and genitofemoral nerves were identified in 82%, 62%, and 41% of surgeries, respectively. Most studies used a nerve-preserving strategy. The role of nerve identification in the development of chronic pain remains uncertain, as well as the optimal nerve handling strategy.

A three-component model of the spinal nerve ramification: Bringing together the human gross anatomy and modern Embryology

Due to its long history, the study of human gross anatomy has not adequately incorporated modern embryological findings; consequently, the current understanding has often been incompatible with recent discoveries from molecular studies. Notably, the traditional epaxial and hypaxial muscle distinction, and their corresponding innervation by the dorsal and ventral rami of the spinal nerve, do not correspond to the primaxial and abaxial muscle distinction, defined by the mesodermal lineages of target tissues. To resolve the disagreement between adult anatomy and embryology, we here propose a novel hypothetical model of spinal nerve ramification. Our model is based on the previously unknown developmental process of the intercostal nerves. Observations of these nerves in the mouse embryos revealed that the intercostal nerves initially had superficial and deep ventral branches, which is contrary to the general perception of a single ventral branch. The initial dual innervation pattern later changes into an adult-like single branch pattern following the retraction of the superficial branch. The modified intercostal nerves consist of the canonical ventral branches and novel branches that run on the muscular surface of the thorax, which sprout from the lateral cutaneous branches. We formulated the embryonic branching pattern into the hypothetical ramification model of the human spinal nerve so that the branching pattern is compatible with the developmental context of the target muscles. In our model, every spinal nerve consists of three components: (1) segmental branches that innervate the primaxial muscles, including the dorsal rami, and short branches and long superficial anterior branches from the ventral rami; (2) plexus-forming intramural branches, the serial homolog of the canonical intercostal nerves, which innervate the abaxial portion of the body wall; and (3) plexus-forming extramural branches, the series of novel branches located outside of the body wall, which innervate the girdle and limb muscles. The selective elaboration or deletion of each component successfully explains the reasoning for the standard morphology and variability of the spinal nerve. Therefore, our model brings a novel understanding of spinal nerve development and valuable information for basic and clinical sciences regarding the diverse branching patterns of the spinal nerve.

Nerve identification in open inguinal hernioplasty: A meta-analysis

Objectives

In open inguinal hernioplasty, three inguinal nerves are encountered in the surgical field. It is advisable to identify these nerves as careful dissection reduces the chances of debilitating post-operative inguinodynia. Recognizing nerves during surgery can be challenging. Limited surgical studies have reported on the identification rates of all nerves. This study aimed to calculate the pooled prevalence of each nerve from these studies.

Material and Methods

We searched PubMed, CENTRAL, CINAHL, ClinicalTrials.gov and Research Square. We selected articles that reported on the prevalence of all three nerves during surgery. A meta-analysis was performed on the data from eight studies. IVhet model from the software MetaXL was used for preparing the forest plot. Subgroup analysis was performed to understand the cause of heterogeneity.

Results

The pooled prevalence rates for Ilioinguinal nerve (IIN), Iliohypogastric nerve (IHN), and genital branch of genitofemoral nerve (GB) were 84% (95% CI 67-97%), 71% (95% CI 51-89%) and 53% (95% CI 31-74%), respectively. On subgroup analysis, the identification rates were higher in single centre studies and studies with a single primary objective as nerve identification. The heterogeneity was significant in all pooled values, excluding the subgroup analysis of IHN identification rates in single-centre studies.

Conclusion

The pooled values indicate low identification rates for IHN and GB. Significant heterogeneity and large confidence intervals reduce the importance of these values as quality standards. Better results are observed in single-centre studies and studies which are focused on nerve identification.

Chronic scrotal pain: Pathogenesis, clinical phenotypes and modern treatment concept (clinical lecture)

Chronic scrotal pain (CSP) is a general term, which defines variety of problems causing discomfort or pain in the scrotum, which can be caused by the problems with testicles and other structures of the scrotum: epididymis, vas deferens, paratesticular structures. For a practicing urologist, the diagnosis and treatment of chronic scrotal pain is always a difficult task due to the many reasons for its appearance and the variety of clinical symptoms. CSP is a widespread but poorly understood condition, the etiology of which often can not be identified. Pain localized in the scrotum makes up 38.8 % of all cases of chronic men’s pelvic pain. From 2.5 to 4.8 % of all visits to the urologist relate to CSP syndrome. Primary scrotal pain syndrome is not associated with infection or other local pathological processes that could cause pain. The treatment of chronic scrotal pain is challenging because the pain often does not react to the traditional treatments.

The purpose of this lecture is to draw the attention of urologists, general practitioners, and everyone who is interested in the problem of treating chronic scrotal pain to the possibilities of modern medicine in solving this multidisciplinary problem.

Open Surgery for Sportsman’s Hernia a Retrospective Study

Sportsman’s hernia is a painful syndrome in the inguinal area occurring in patients who play sports at an amatorial or professional level. Pain arises during sport, and sometimes persists after activity, representing an obstacle to sport resumption. A laparoscopic/endoscopic approach is proposed by many authors for treatment of the inguinal wall defect. Aim of this study is to assess the open technique in terms of safety and effectiveness, in order to obtain the benefit of an open treatment in an outpatient management. From October 2017 to July 2019, 34 patients underwent surgery for groin pain syndrome. All cases exhibited a bulging of the inguinal posterior wall. 14 patients were treated with Lichtenstein technique with transversalis fascia plication and placement of a polypropylene mesh fixed with fibrin glue. In 20 cases, a polypropylene mesh was placed in the preperitoneal space. The procedure was performed in day surgery facilities. Early or late postoperative complications did not occur in both groups. All patients returned to sport, in 32 cases with complete pain relief, whereas 2 patients experienced mild residual pain. The average value of return to sport was 34.11 ± 8.44 days. The average value of return to play was 53.82 ± 11.69 days. With regard to postoperative pain, no substantial differences between the two techniques were detected, and good results in terms of the resumption of sport were ensured in both groups. Surgical treatment for sportsman’s hernia should be considered only after the failure of conservative treatment. The open technique is safe and allows a rapid postoperative recovery.

Manual Therapy Treatment for Penile Pain- A Clinical Case Report with 6-Month Follow-up

BACKGROUND

Male genital pain, which is neither related to genitourinary nor other obvious pathology, is an uncommon symptom in male patients and not frequently treated using manual therapy. The purpose of this case study is to describe a clinical reasoning process in combination with anatomy-based differential diagnosis and manual treatment for genital pain.

CASE DESCRIPTION

A male patient with a 3-week acute onset of genital pain was hospitalized and referred for evaluation and treatment after unsuccessful treatment with medication and acupuncture. Clinical examination was performed indicating a possible nerve entrapment followed by interventions of ligamentous articular strain, high-velocity low-amplitude (HVLA) manipulation, and strain- and counterstain, coupled with soft tissue stretching to lumbar and inguinal areas to address a possible lumbar referral potentially from L1 and/or ilioinguinal nerve entrapment.

OUTCOMES

After 4 consecutive days of manipulative treatment, pain decreased from 9/10 to 0/10 and the Barthel Index improved from 50 to 95. A 6-month follow-up revealed complete resolution of symptoms with no recurrence.

DISCUSSION

This case illustrates that a detailed history and examination along with a reasoned diagnostic process to determine an appropriate intervention strategy may improve patient care using manual therapy techniques.

CONCLUSION

By utilizing a deductive reasoning process related to the penile area, clinicians may better apply manual therapy techniques for successful treatment.

Ilioinguinal Nerve Neurectomy is better than Preservation in Lichtenstein Hernia Repair: A Systematic Literature Review and Meta-analysis

OBJECTIVE

This study aimed to evaluate the incidence of chronic groin pain (primary outcome) and alterations of sensitivity (secondary outcome) after Lichtenstein inguinal hernia repair, comparing neurectomy with ilioinguinal nerve preservation surgery. The exact cause of chronic groin postoperative pain after mesh inguinal hernia repair is usually unclear. Section of the ilioinguinal nerve (neurectomy) may reduce postoperative chronic pain.

METHODS

We followed PRISMA guidelines to identify randomized studies reporting comparative outcomes of neurectomy versus ilioinguinal nerve preservation surgery during Lichtenstein hernia repairs. Studies were identified by searching in PubMed, Scopus, and Web of Science from April 2020. The protocol for this systematic review and meta-analysis was submitted and accepted from PROSPERO: CRD420201610.

RESULTS

In this systematic review and meta-analysis, 16 RCTs were included and 1550 patients were evaluated: 756 patients underwent neurectomy (neurectomy group) vs 794 patients underwent ilioinguinal nerve preservation surgery (nerve preservation group). All included studies analyzed Lichtenstein hernia repair. The majority of the new studies and data comes from a relatively narrow geographic region; other bias of this meta-analysis is the suitability of pooling data for many of these studies. A statistically significant percentage of patients with prosthetic inguinal hernia repair had reduced groin pain at 6 months after surgery at 8.94% (38/425) in the neurectomy group versus 25.11% (113/450) in the nerve preservation group [relative risk (RR) 0.39, 95% confidence interval (CI) 0.28-0.54; Z = 5.60 (P < 0.00001)]. Neurectomy did not significantly increase the groin paresthesia 6 months after surgery at 8.5% (30/353) in the neurectomy group versus 4.5% (17/373) in the nerve preservation group [RR 1.62, 95% CI 0.94-2.80; Z = 1.74 (P = 0.08)]. At 12 months after surgery, there is no advantage of neurectomy over chronic groin pain; no significant differences were found in the 12-month postoperative groin pain rate at 9% (9/100) in the neurectomy group versus 17.85% (20/112) in the inguinal nerve preservation group [RR 0.50, 95% CI 0.24-1.05; Z = 1.83 (P = 0.07)]. One study (115 patients) reported data about paresthesia at 12 months after surgery (7.27%, 4/55 in neurectomy group vs. 5%, 3/60 in nerve preservation group) and results were not significantly different between the two groups [RR 1.45, 95% CI 0.34, 6.21;Z = 0.51 (P = 0.61)]. The subgroup analysis of the studies that identified the IIN showed a significant reduction of the 6th month evaluation of pain in both groups and confirmed the same trend in favor of neurectomy reported in the previous overall analysis: statistically significant reduction of pain 6 months after surgery at 3.79% (6/158) in the neurectomy group versus 14.6% (26/178) in the nerve preservation group [RR 0.28, 95% CI 0.13-0.63; Z = 3.10 (P = 0.002)].

CONCLUSION

Ilioinguinal nerve identification in Lichtenstein inguinal hernia repair is the fundamental step to reduce or avoid postoperative pain. Prophylactic ilioinguinal nerve neurectomy seems to offer some advantages concerning pain in the first 6th month postoperative period, although it might be possible that the small number of cases contributed to the insignificancy regarding paresthesia and hypoesthesia. Nowadays, prudent surgeons should discuss with patients and their families the uncertain benefits and the potential risks of neurectomy before performing the hernioplasty.

Dermatome Mapping Test in the analysis of anatomo-clinical correlations after inguinal hernia repair

Background

Nerve identification is recommended in inguinal hernia repair to reduce or avoid postoperative pain. The aim of this prospective observational study was to identify nerve prevalence and find a correlation between neuroanatomy and chronic neuropathic postoperative inguinal pain (CPIP) after 6 months.

Material

A total of 115 patients, who underwent inguinal hernia mesh repair (Lichtenstein tension-free mesh repair) between July 2018 and January 2019, were included in this prospective observational study. The mean age and BMI respectively resulted 64 years and 25.8 with minimal inverse distribution of BMI with respect to age. Most of the hernias were direct (59.1%) and of medium dimension (47.8%). Furthermore, these patients were undergoing Dermatome Mapping Test in preoperatively and postoperatively 6 months evaluation.

Results

Identification rates of the iliohypogastric (IH), ilioinguinal (II) and genitofemoral (GF) nerves were 72.2%, 82.6% and 48.7% respectively. In the analysis of nerve prevalence according to BMI, the IH was statistically significant higher in patients with BMI < 25 than BMI ≥ 25 P (< 0.05). After inguinal hernia mesh repair, 8 patients (6.9%) had chronic postoperative neuropathic inguinal pain after 6 months. The CPIP prevailed at II/GF dermatome. The relation between the identification/neurectomy of the II nerve and chronic postoperative inguinal pain after 6 months was not significant (P = 0.542).

Conclusion

The anatomy of inguinal nerve is very heterogeneous and for this reason an accurate knowledge of these variations is needed during the open mesh repair of inguinal hernias. The new results of our analysis is the statistically significant higher IH nerve prevalence in patients with BMI < 25; probably the identification of inguinal nerve is more complex in obese patients. In the chronic postoperative inguinal pain, the II nerve may have a predominant role in determining postoperative long-term symptoms. Dermatome Mapping Test in an easy and safe method for preoperative and postoperative 6 months evaluation of groin pain. The most important evidence of our analysis is that the prevalence of chronic pain is higher when the nerves were not identified.

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.