UNASSIGNED: Several anatomical variations of the ilioinguinal nerve branches have been recorded in older studies. Knowledge of these variations is useful for the improvement of peripheral nerve blocks and avoidance of iatrogenic nerve injuries during abdominal surgeries. The purpose of this study is to perform a systematic review of the literature about the anatomical topography and variations of the ilioinguinal nerve.
UNASSIGNED: An extensive search in PubMed, Scopus, and Web of Science electronic databases was conducted by the first author in November 2021, with the use of the PRISMA guidelines. Anatomical or cadaveric studies about the origin, the course, and the distribution of the ilioinguinal nerve were included in this review. Thirty-one cadaveric studies were included for qualitative analysis.
UNASSIGNED: Several anatomical variations of the ilioinguinal 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 ilioinguinal nerve ranged from 0% to 35%, its origin from L1 ranged from 65% to 100%, and its isolated emergence from psoas major ranged from 47% to 94.5%. Numerous anatomical variations of the ilioinguinal nerve exist, not commonly cited in classic anatomical textbooks. The branches of the ilioinguinal nerve may be damaged during spinal anesthesia and surgical procedures in the lower abdominal region.
UNASSIGNED: Therefore, a better understanding of the regional anatomy and its variations is of vital importance for the prevention of ilioinguinal nerve injuries.

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.
CONCLUSIONS: 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.

BACKGROUND: Lateral lumbar interbody fusion (LLIF) is commonly used to address various lumbar pathologies. LLIF using the prone transpsoas (PTP) approach has several potential advantages, allowing simultaneous access to the anterior and posterior columns of the spine. The aim of this study was to report the 1-year outcomes of LLIF via PTP.
METHODS: This is a retrospective review of 97 consecutive patients who underwent LLIF via PTP. Radiographic parameters, including lumbar-lordosis, segmental-lordosis, anterior disc height, and posterior disc height, were measured on preoperative, initial-postoperative, and 1-year postoperative imaging. Patient-reported outcomes measures, including Oswestry Disability Index, visual analog scale (VAS), pain EQ5D, and postoperative complications, were reviewed.
RESULTS: Ninety-seven consecutive patients underwent 161 levels of LLIF. Fifty-seven percent underwent 1-level LLIF, 30% 2-level LLIF, 6% 3-level LLIF, and 7% 4-level LLIF. The most common level was L4 to L5 (35%), followed by L3 to L4 (33%), L2 to L3 (21%), and L1 to L2 (11%). Significant improvements were noted at initial and 1-year postoperative periods in lumbar-lordosis (2° ± 10°, P = 0.049; 3° ± 9°, P = 0.005), segmental-lordosis (6° ± 5°, P < 0.001; 5° ± 5°, P < 0.001), anterior disc height (8 mm ± 4 mm, P < 0.001; 7 mm ± 4 mm, P < 0.001), and posterior disc height (3 mm ± 2 mm, P < 0.001; 3 mm ± 2 mm, P < 0.001). Significant improvements were seen in Oswestry Disability Index at 6 weeks (P = 0.002), 6 months (P < 0.001), and 1 year (P < 0.001) postoperatively; pain EQ5D at 6 weeks (P < 0.001), 6 months (P < 0.001), and 1 year (P < 0.001) postoperatively; and leg and back visual analog scale at 2 weeks (P < 0.001), 6 months (P < 0.001), and 1 year (P < 0.001) postoperatively. The average length of stay was 2.5 days, and the most common complications were ipsilateral hip flexor pain (46%), weakness (59%), and contralateral hip flexor pain (29%).
CONCLUSIONS: PTP is a novel way of performing LLIF. These 1-year data support that PTP is an effective, safe, and viable approach with similar patient-reported outcome measures and complications profiles as LLIF performed in the lateral decubitus position.
METHODS:

BACKGROUND: The lateral femoral cutaneous nerve is derived from the dorsal branches of the L2 and L3 spinal nerves. It travels across the pelvis and heads towards the anterior superior iliac spine. It passes under the lateral part of the inguinal ligament and then divides into two branches, which are responsible for sensory innervation of the anterolateral and lateral skin of the thigh. However, the course of this nerve can vary morphologically. Numerous differences have been observed in its exit from the pelvis and in the number of its main trunks and branches. Additionally, its angle with the inguinal ligament and its placement in relation to other structures (such as the femoral artery, femoral nerve, and the sartorius and iliacus muscles) also vary. All of these variants have potential clinical implications. Therefore, the aim of this review is to present the morphological variability of the lateral cutaneous nerve and to explore how these anatomical differences can introduce clinical concerns.
METHODS: Presented review of the literature was written based on over 30 studies. Comprehensive literature search was done using PubMed in order to study the morphological variability of lateral femoral cutaneous nerve (LFCN). To be included in this review studies needed to be meet certain criteria: been published before December 2023, present information valuable to this paper (variability of lateral femoral cutaneous nerve/clinical significance). The search included how LFCN vary either among fetuses and adults in the aim of providing more complex information about the variability of this nerve. During the search key words as following were used. No particular references were excluded from the analysis. All relevant studies were included, and citation tracking was used to identify publications.
RESULTS: This review presents the description of variability of LFCN and its potential clinical impact. In the review differences in adult and fetuses were considered, morphological variability were divided into 4 groups: the origin of the nerve, the way it leaves the pelvis, the branching pattern, the angle between LFCN and surrounding structures and then, clinical significance were considered basing on available literature.

Cadaveric study; To describe the characteristics of the nerve and its relationship with the lumbar intervertebral disc and psoas major muscle. Nerve injury is an understudied complication of extreme lateral interbody fusion. A detailed description of the nerve anatomy would be helpful for surgeons to minimize the risk of this complication. The lumbar plexus and lumbar sympathetic nerve of 10 embalmed male cadavers were dissected, and the distribution, number, and spatial orientation of the nerves on the L1/2 to L4/5 intervertebral discs were examined. Metal wires were applied along nerve paths through the psoas major muscle. The position of the nerves was examined on CT. In zone III at L1/2 and L4/5, no nerves were found. In zone II and zone III at L2/3, no lumbar plexus was found, and only the ramus communicans passed through. At the L1-L5 level, the density of nerves in the posterior half of the psoas major muscle was greater than that in the anterior half. The lumbar plexus was found in all of zone IV. The genitofemoral nerve emerges superficially and anteriorly from the medial border of the psoas major at the L3-4 level, but at the L1/2 level, the sympathetic trunk is located in zone II. The remaining disc-level sympathetic trunks appear in zone I. No nerves were found in zone III of the L1/2 or L4/5 disc. In zones II and III of L2/3, the lumbar plexus appears safe. The genitofemoral nerve travels through zones II and III of L3/4. The distribution density of nerves in the posterior half of the psoas major muscle was greater than that in the anterior half of that muscle at the L1-L5 level.

Meralgia paresthetica is a common but probably underrecognized syndrome caused by dysfunction of the lateral femoral cutaneous nerve. The diagnosis is based on the patient\'s description of sensory disturbance, often painful, on the anterolateral aspect of the thigh, with normal strength and reflexes. Sensory nerve conduction studies and somatosensory evoked potentials may be used to support the diagnosis, but both have technical limitations, with low specificity and sensitivity. Risk factors for meralgia paresthetica include obesity, tight clothing, and diabetes mellitus. Some cases are complications of hip or lumbar spine surgery. Most cases are self-limited, but a small proportion of patients remain with refractory and disabling symptoms. Treatment options include medications for neuropathic pain, neurolysis, neurectomy, and radioablation, but controlled trials to compare efficacy are lacking.

Patients with severe cardiopulmonary morbidity present a unique challenge to peri- and intraoperative providers. Inducing general anesthesia in this patient population poses the risk of adverse events that could lead to poor surgical outcomes, prolonged debilitation, or death. Therefore, it is important that anesthesiologists become comfortable with preoperative evaluation as well as alternative strategies to providing surgical anesthesia. This case report details the clinical course of a patient with severe cardiopulmonary morbidity who underwent open inguinal hernia repair without oral or intravenous sedation after receiving multi-level paravertebral blocks in addition to isolated ilioinguinal and iliohypogastric nerve blocks. This medically challenging case provides educational value regarding preoperative evaluation, pertinent anatomy and innervation, and the importance of patient-centered care and communication.

The lumbar plexus provides innervation to the lower limbs and is essential in enabling motor movement and sensation in the lower limbs. Some of its branches also innervate the muscles in the pelvic girdle. Compared to the brachial plexus in the upper limbs, the lumbar plexus appears to garner less recognition among physicians and surgeons. However, it is important to understand the anatomy of the lumbar plexus and its branches along with the innervation they enable, as injury to them can cause plexopathies and pathologies that should be recognised by any treating clinician. Lumbar disc herniation, trauma and entrapment by muscles or hypertrophic ligaments are common causes of lumbar plexus or nerve injuries. A video was produced to demonstrate the examination techniques explained in this article. To provide comprehensive examination of the lower limbs, the sciatic nerve and its branches are also included in the examination video.

METHODS: Prospective cohort study.
OBJECTIVE: In this study we aim to assess the difference in triggered EMG readings throughout different depths in the psoas muscle during the lateral approach to the lumbar spine and their effect on surgeon decision making.
METHODS: Three surgeons, practicing at different institutions, assessed triggered EMG readings during the trans psoas approach at the level of the disc and 5,10 and 15 millimeters into the psoas muscle with sequential dilators. Measurement of distance into the psoas muscle was done with a specially designed instrument. Results of anterior and posterior directed stimulation as well as the delta value between these were recorded and underwent statistical analysis. Patients who had partial readings were excluded from the study.
RESULTS: A total of 40 levels in 35 patients were included in the study. There was no significant difference found between means of anterior or posterior threshold readings along the different distance groups. A significant difference was found (P = .024) in the mean difference between the distance groups with a decrease in the difference between anterior and posterior threshold values found as the distance from the disc space increased. None of the surgeons reported a decision to abort the fusion of a spinal level.
CONCLUSIONS: In the trans-psoas approach to the lumbar spine, the assessment of the location of the femoral nerve using directional neuromonitoring when advancing in the psoas muscle shows no clear benefit as opposed to stimulating solely when adjacent to the disc space.

OBJECTIVE: To compare motor effects and analgesic efficacy following an ultrasound-guided lateral approach to lumbar plexus blockade at L7 and sciatic nerve blockade (LPSNB) against epidural injection in dogs undergoing tibial plateau leveling osteotomy (TPLO).
METHODS: Prospective, randomized, blinded clinical trial.
METHODS: A total of 27 healthy adult dogs undergoing unilateral TPLO surgery.
METHODS: Dogs were allocated to either LPSNB (bupivacaine 2 mg kg-1, 0.75%) or epidural (morphine PF 0.1 mg kg-1 and bupivacaine 0.5 mg kg-1, 0.75%). Other aspects of clinical management were identical, including anesthetic drug protocol, area of presurgical clipping and bladder care. Time to perform the block, response to surgical stimuli, pain scores, rescue analgesia, time to stand and walk, motor score and time to first urination were recorded. One evaluator, unaware of treatment status, performed all evaluations. Student\'s t-test or Mann-Whitney U test was used to compare continuous variables between groups, and Fisher\'s exact test for categorical variables.
RESULTS: Median (range) times to stand and walk were shorter for LPSNB [60 (40-120) minutes and 90 (60-150) minutes, respectively, p = 0.003] than for epidural [150 (120-240) minutes and 180 (120-360) minutes, respectively, p = 0.006]. Four dogs required rescue intraoperatively (three in epidural group, one in LPSNB group, p = 0.438). Pain scores over the 24 hour evaluation period were similar, and not significantly different, for each group. Time to spontaneous urination [LPSNB, 330 (240-360) minutes; epidural, 300 (120-1440) minutes, p = 1.0] did not differ between groups.
CONCLUSIONS: An ultrasound-guided lateral paravertebral approach to the lumbar plexus within the psoas compartment at L7, combined with sciatic nerve blockade, allows faster return to normal motor function, with similar pain control and impact on urination when compared with epidural in dogs after TPLO surgery.