A practical approach to the lateral cutaneous nerve of the thigh: an anatomical study

Anatomical Analysis of the Lateral Femoral Cutaneous Nerve and Its Passage beneath the Inguinal Ligament

BACKGROUND

Meralgia paraesthetica is a mononeuropathy of the lateral femoral cutaneous nerve. According to the literature, the nerve travels beneath the inguinal ligament 1.3 to 5.1 cm medial to the anterior superior iliac spine. Compression at this site may cause pain and paresthesia. The aim of this study was to provide more accurate measurements to improve the diagnostic and surgical management of meralgia paraesthetica.

METHODS

The lateral femoral cutaneous nerve was dissected bilaterally in 50 Thiel-embalmed human cadavers. Measurements were performed with a standard caliper at the superior and inferior margins of the inguinal ligament. The distance from the inner lamina of the anterior superior iliac spine to the medial margin of the lateral femoral cutaneous nerve was measured. Data were collected and statistical analysis was performed with R.

RESULTS

Ninety-three lateral femoral cutaneous nerves of 50 cadavers were dissected. In 6 percent of cadavers, the lateral femoral cutaneous nerve could not be found. The mean distance from the inner lamina of the anterior superior iliac spine to the lateral femoral cutaneous nerve's medial border was 2.1 ± 1.3 cm (range, 0.2 to 6.4 cm; 95 percent CI, 1.8 to 2.4 cm) at the superior margin of the inguinal ligament and 1.9 ± 1.4 cm (range, 0.2 to 3.0 cm; 95 percent CI, 1.6 to 2.2 cm) at the inferior border of the inguinal ligament.

CONCLUSION

This anatomical study shows that the majority of the lateral femoral cutaneous nerve passes beneath the inguinal ligament in a very narrow area of 0.6 cm.

Ultrasound-guided, direct suprainguinal injection for fascia iliaca block for total hip arthroplasty: A retrospective study

BACKGROUND

Peripheral regional block combined with general anesthesia might be a preferable anesthetic regimen for elderly patients undergoing total hip arthroplasty.

AIM

To investigate whether ultrasound-guided, direct suprainguinal injection for fascia iliaca block accelerated recovery after general anesthesia and relieved postoperative pain after total hip arthroplasty.

METHODS

Patients who underwent total hip arthroplasty under general anesthesia in 2015 or 2019 at The Second Affiliated Hospital of Xuzhou Medical University were retrospectively analyzed. The patients were grouped based on whether preoperative suprainguinal fascia iliaca block was performed or not. The time to tracheal extubation and time spent in the post-anesthesia care unit (PACU), intraoperative remifentanil dosage, fentanyl consumption in the PACU, postoperative cumulative fentanyl consumption within 48 h after operation, visual analogue scale at rest and during movement on the first and second days after surgery, and adverse reactions were compared.

RESULTS

Thirty-one elderly patients who underwent total hip arthroplasty were included in the study (block group, n = 16; no-block group, n = 15). The visual analog scale scores at rest and during movement on the first and second days were significantly lower in the block group than in the no-block group (all P < 0.05). Compared with the no-block group, the intraoperative remifentanil dosage was lower, the time to tracheal extubation and the time spent in the PACU were shorter in the block group (all P < 0.01). Fentanyl consumption in the PACU and postoperative cumulative fentanyl consumption in 48 h after operation were lower in the block group (all P < 0.01). The incidence of dizziness was higher in the no-block group than in the block group (P = 0.037).

CONCLUSION

Ultrasound-guided, direct suprainguinal injection for fascia iliaca block led to faster recovery after general anesthesia and early postoperative pain relief in elderly patients undergoing total hip arthroplasty.

Ultrasound-Guided Suprainguinal Fascia Iliaca Technique Provides Benefit as an Analgesic Adjunct for Patients Undergoing Total Hip Arthroplasty

Analgesia after total hip arthroplasty is often accomplished by the fascia iliaca compartment block, traditionally performed below the inguinal ligament, to anesthetize both femoral and lateral femoral cutaneous nerves. The course of the lateral femoral cutaneous nerve below the inguinal ligament is variable as opposed to consistent above the inguinal ligament in the pelvis. In this case series including 5 patients, we demonstrate that an ultrasound-guided suprainguinal fascia iliaca approach would consistently anesthetize the lateral femoral cutaneous nerve along with anterior cutaneous femoral nerve branches and provide cutaneous analgesia after total hip arthroplasty, as shown by decreased opioid consumption.

The surgical anatomy of the lateral femoral cutaneous nerve in the inguinal region: a meta-analysis

Purpose

Several variations in the anatomy and injury of the lateral femoral cutaneous nerve (LFCN) have been studied since 1885. The aim of our study was to analyze the available data on the LFCN and find a true prevalence to help in the planning and execution of surgical procedures in the area of the pelvis, namely inguinal hernia repair.

Methods

A search of the major medical databases was performed for LFCN anatomy. The anatomical data were collected and analyzed.

Results

Twenty-four studies (n = 1,720) were included. The most common pattern of the LFCN exiting the pelvis was medial to the Sartorius as a single branch. When it exited in this pattern, it did so on average 1.90 cm medial to the anterior superior iliac spine (ASIS).

Conclusions

The LFCN and its variations are important to consider especially during inguinal hernia repair, abdominoplasty, and iliac bone grafting. We suggest maintaining a distance of 3 cm or more from the ASIS when operating to prevent injury to the LFCN.

Electronic supplementary material

The online version of this article (doi:10.1007/s10029-016-1493-7) contains supplementary material, which is available to authorized users.

Ultrasound of the lateral femoral cutaneous nerve in asymptomatic adults

Background

To define the sites where the lateral femoral cutaneous nerve (LFCN) is more easily visualized and to describe the anatomical variations of the LFCN.

Methods

A total of 240 LFCNs in 120 volunteers were evaluated with 18 MHz ultrasound; the intermuscular space between the tensor fasciae latae muscle and the sartorius was used as an initial sonographic landmark. The time taken to identify the nerve was recorded. The number of nerve branches at the level of the inguinal ligament (IL) and the relationship between the LFCN and the IL was assessed. The nerve cross-sectional area (CSA) of the LFCN and the distance between the LFCN and the anterior superior iliac spine was measured.

Results

Each nerve was identified using ultrasound in all participants. The mean time for identifying the nerve was 7s for unilateral LFCNs. The nerve passed under the IL in 198 cases, whereas in 44 cases, it passed through to the IL. The LFCN consisted of 1–4 branches just after its passage under or through the IL. The CSA of the LFCN was 1.04±0.44 mm², and the mean distance between the LFCN and the anterior superior iliac spine was 15.6 ± 4.2 mm.

Conclusions

It is easier to identify the LFCN if the intermuscular space between the tensor fasciae latae muscle and the sartorius is used as an initial sonographic landmark. The anatomical variation of the LFCN can be viewed with high-frequency ultrasound.