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Background: Together with an increased interest in minimally invasive lateral transpsoas approach to the lumbar spine goes a demand for detailed anatomical descriptions of the lumbar plexus. Although definitions of safe zones and essential descriptions of topographical anatomy have been presented in several studies, the existing literature expects standard appearance of the neural structures. Therefore, the aim of this study was to investigate the variability of the extrapsoas portion of the lumbar plexus in regard to the lateral transpsoas approach., Methods: A total of 260 lumbar regions from embalmed cadavers were utilized in this study. The specimens were dissected as per protocol and all nerves from the lumbar plexus were morphologically evaluated., Results: The most common variation of the iliohypogastric and ilioinguinal nerves was fusion of these two nerves (9.6%). Nearly in the half of the cases (48.1%) the genitofemoral nerve left the psoas major muscle already divided into the femoral and genital branches. The lateral femoral cutaneous nerve was the least variable one as it resembled its normal morphology in 95.0% of cases. Regarding the variant origins of the femoral nerve, there was a low formation outside the psoas major muscle in 3.8% of cases. The obturator nerve was not variable at its emergence point but frequently branched (40.4%) before entering the obturator canal. In addition to the proper femoral and obturator nerves, accessory nerves were present in 12.3% and 9.2% of cases, respectively., Conclusion: Nerves of the lumbar plexus frequently show atypical anatomy outside the psoas major muscle. The presented study provides a compendious information source of the possibly encountered neural variations during retroperitoneal access to different segments of the lumbar spine., (© 2024. The Author(s).)

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.

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.

Introduction and Hypothesis: To describe the relationships between pelvic bony landmarks to points along the third sacral nerve and to uterosacral ligament suspension sutures., Methods: Three transvaginal uterosacral ligament suspension sutures were placed bilaterally in unembalmed female human cadavers. The third sacral nerve was marked at the foramen (S3a) and at two additional points at 1-cm intervals along its course caudally (S3b, S3c). Three bony pelvic landmarks were identified and marked, including the ischial spine, pubic symphysis, and coccyx. Distances from each landmark to each suture and nerve point were measured. The distance from each landmark to each S3 nerve point was extended radially, encompassing an arbitrary zone in which sutures may be placed and thus where nerve injury may occur. Zones of potential nerve injury included: zone A (closest to the sacral nerve root), zone B, and zone C (closest to the landmark). Descriptive statistics were used and comparisons were made using Student's t test and ANOVA., Results: Ten cadaver specimens were dissected. For the ischial spine, the distances to points S3a, S3b, and S3c were 6.3, 5.4, and 4.6 cm respectively. Approximately two thirds of the sutures were noted beyond zone C, indicating a potentially increased risk of nerve injury with suture placement in zones farthest from the ischial spine given their proximity to the sacral nerve., Conclusions: Using the ischial spine as a landmark, increased sacral nerve injury could result from suture placement beyond the mean distance of 4.6 cm from the ischial spine. The use of bony landmarks in avoiding sacral nerve injury may be as important as suture depth and angle of suture placement.

Knowledge of segmental innervation of skeletal muscles is essential for diagnosing lumbar radiculopathy. Myotomes and dermatomes are traditionally thought to be innervated by a single spinal segment, but experimental studies have shown that this pattern of segmental innervation allows considerable overlap. This implies that muscles (or dermatomes) are innervated not only by axons of one spinal segment, but also partially by axons of adjacent spinal levels. We describe a patient in whom overlap in segmental innervation complicated adequate diagnosis of a recurrent lumbar hernia. Further, we present an outline of electrophysiological and anatomical studies on segmental innervation.

In laparoscopic hernia repairs, the staples used to affix prosthetic mesh have resulted in entrapment neuropathies. This paper describes the diagnosis and treatment of nine cases of entrapment neuropathy. Injuries to all the branches of the lumbar plexus, with the exception of the obdurator nerve, have been treated. Generally, the entrapments are self-limiting, but chronic disability requiring surgical intervention can occur. Staple removal and neurolysis controlled the severe, chronic pain of one femoral nerve entrapment. A thorough understanding of the anatomy of these nerves can prevent stapling in the areas of danger and thus greatly reduce the incidence of this complication.

The laparoscopic approach has recently been utilized for inguinal hernia repair. Nerve injuries are now being reported. The femoral branch of the genitofemoral nerve and the lateral cutaneous nerve of the thigh appear most at risk. The purpose of this study was to determine the feasibility of identifying these nerves laparoscopically on either a routine or selective basis. Twenty patients scheduled for laparoscopic inguinal hernia repair were prospectively selected. An attempt was made to identify these nerves so that optimum placement of staples could occur. The femoral branch of the genitofemoral nerve was identified in 19 of 20 patients and the lateral cutaneous nerve of the thigh in 18 of 20 patients. A review of 125 laparoscopic inguinal hernia repairs revealed five nerve injuries (4%). Details are given and recommendations discussed. Knowledge of preperitoneal anatomy and awareness of the location of these nerves should lead to a safer dissection and more accurate application of staples, hopefully decreasing the incidence of nerve injury.