Relationships of the lateral femoral cutaneous nerve to bony landmarks

Sonographic Evaluation of the Lateral Femoral Cutaneous Nerve: Single-Institution Experience and Pictorial Review

ABSTRACT

The location of the lateral femoral cutaneous nerve (LFCN) makes it susceptible to injury with trauma, external compression, and iatrogenic injury. The objectives of this study were to report the single-institution efficacy of LFCN visualization on ultrasound (US), define the clinical characteristics of patients with LFCN palsy, and describe sonographic appearances of LFCN abnormalities by pictorial review. A retrospective chart review of LFCN cases evaluated using US at a single institution was performed, documenting rate of visibility on US, mode of nerve injury, and US imaging findings. Nerve visibility rates on US were correlated with magnetic resonance imaging (MRI) when both modalities were used. Imaging findings were confirmed with clinical/surgical history and follow-up. Retrospective review found that 170 patients underwent US for LFCN evaluation in the last 10 years. Injury was associated with surgical intervention in 56% of cases, and perineural scarring was the most common pathology described using US. Lateral femoral cutaneous nerve was visible on US in 97% of cases; MRI visualized LFCN in 60%. Chart review showed US as an effective tool in evaluating LFCN pathology, with a higher visualization rate than MRI. Through pictorial review, the array of LFCN pathology sonographically detectable is demonstrated.

Surgical course of lateral femoral cutaneous nerve during anterior exposure of paediatric hips: an observational study

Anterior approach to the hip joint is commonly used for paediatric hip disorders. Lateral femoral cutaneous nerve (LFCN) is always exposed and dissected in this approach before deep dissection is carried out. The course of this nerve has been described in adults but there is a lack of literature regarding this in the paediatric age group. This study aimed to find the surgical anatomy of LFCN in children during the anterior approach to the hip. A total of 51 paediatric hip surgeries were done in 45 children for various hip disorders. The anterior exposure was done by the Somerville approach (Bikini incision). During surgical exposure, LFCN was exposed and its relationship to anterior superior iliac spine (ASIS), inguinal ligament and sartorius muscle was observed. In most of the cases (45/51) it was found as a single trunk below the inguinal ligament and medial to the ASIS. In one hip, multiple branches of the nerve were found just below the inguinal ligament. In four hip exposures, the nerve was not found in the surgical field and in one case nerve was accidentally cut during surgery as it was lying adherent to ASIS. There was no significant correlation between the observational parameters of the nerve with anthropometric variables. Nerve was mostly seen in area 5-25 mm medial to ASIS and 10-50 mm below the ASIS in 80% of our surgical exposures where the nerve was isolated. We observed that once LFCN is dissected, the injury during further surgical procedures can be prevented.

Cadaveric Study of Variations in the Course of Lateral Femoral Cutaneous Nerve: Insight to Prevent Injury

Objective

A recent spurt in incidence of meralgia paresthetica to 0.1-81% due to minimally invasive anterior approach to hip joint has resulted in reinterest in anatomy of lateral femoral cutaneous nerve (LFCN). Familiarity with variations in the course of LFCN will reduce the morbidity associated with orthopedic procedures around the anterior superior iliac spine (ASIS) and inguinal ligament (IL).

Methods

Twenty five adult human formalin embalmed cadavers were dissected. Course and relations of nerve to ASIS, IL and sartorius muscle was noted, distance of nerve from ASIS at IL was measured and statistically analyzed.

Results

Mean distance of LFCN from ASIS at IL was 1.73±1.15 cm. Differences between two sides and sexes was statistically not significant (p=0.51 and p=0.96 respectively). Inferomedial to ASIS, 94% of LFCNs crossed IL with 92% of them present within 4 cm medial to ASIS. Majority of LFCNs (90%) exited pelvis and entered thigh posterior to IL. Out of these nerves 48% were single trunks on entry into thigh, then bifurcated into anterior and posterior branches. Remaining LFCNs bifurcated proximal to IL or at level of IL. Trifurcations were seen in 6% while a rare case of pentafication was observed. In 66% main trunk/branches were present in intermuscular cleft between sartorius muscle and tensor fascia lata.

Conclusions

Care should be exercised by surgeons while dissecting around IL as more than half of nerves are liable to be injured during operative procedures. This would help in better anticipation of problem, acceptance and reducing litigation.

Protection of the innervation of the tensor fasciae latae in hip direct anterior and anterolateral approaches: a cadaver study

PURPOSE

This study aims to reveal the exact course of the superior gluteal nerve (SGN) branch innervating the tensor fascia lata (TFL) and show how it can be protected in the direct anterior approach (DAA) and anterolateral approach (ALA).

METHODS

The anterolateral regions of 22 thighs from formalin-fixed cadavers were dissected. 3 anatomical points were determined. Point A, B, C indicates where the SGN enters the gluteus minimus (GMin) fibres, the SGN leaves the gluteal muscles, the SGN enters the TFL, respectively. Measurements were made on 3 separate lines.

RESULTS

On the anterior superior iliac spine (ASIS) and the head of the fibula line (Line 1), the horizontal-vertical distances from point B and C to the ASIS were 7.99 ± 3.65 mm-40.40 ± 11.50 mm and 11.74 ± 6.61 mm-70.35 ± 14.11 mm respectively. The horizontal-vertical distances from point A, B, C to the greater trochanter (GT) were 32.41 ± 9.97 mm-55.28 ± 12.25 mm; 67.70 ± 8.54 mm-17.76 ± 13.57 mm; 63.92 ± 9.96 mm-13.00 ± 7.92 mm on the GT and the head of the fibula line (Line 2), respectively. The horizontal-vertical distances from point A, B, C to the GT were 24.58 ± 9.83 mm-42.54 ± 12.86 mm; 9.45 ± 7.92 mm-36.25 ± 9.06 mm; 26.18 ± 11.12 mm-64.05 ± 11.67 mm on the ASIS and the GT line (Line 3).

CONCLUSIONS

In the DAA, the increased risk of damaging the branch of the SGN that innervates the TFL must be kept in mind. The protection of this branch can be ensured with easy and applicable rules.

Surgical anatomy of the lateral femoral cutaneous nerve for meralgia paraesthetica: A simple technical guide for surgeons and trainees alike

Meralgia paraesthetica is an entrapment neuropathy of the lateral femoral cutaneous nerve, usually due to compression at the inguinal ligament as the nerve passes from the pelvis into the thigh. Surgical decompression of the lateral femoral cutaneous nerve is a simple and effective treatment option, but the surgical anatomy of the area is not always familiar to neurosurgeons and neurosurgical trainees alike. This paper is a simple review of the relevant surgical anatomy and the surgical steps of lateral femoral cutaneous nerve decompression, with the aim of providing the busy surgeon and trainee a quick and easy reference guide to the procedure.

Incidence of lateral femoral cutaneous nerve lesions after direct anterior approach primary total hip arthroplasty - a literature review

INTRODUCTION

Lesions of the lateral cutaneous femoral nerve are a reported complication of the direct anterior approach (DAA) for total hip arthroplasty (THA). Little is known about the incidence rates of this lesion. The goal of this study was to answer the following questions: (1) Is the true incidence rate of LFCN lesions after DAA THA known? (2) What are the reasons for the wide range of reported incidence rates in the literature? (3) Are surgeons increasingly aware of the significance of LFCN lesions?

METHODS

A US Medical Library of Medicine database search was performed for DAA THA. In total, 1261 search results were screened for reported LFCN lesions.

RESULTS

Forty-five studies were included reporting LFCN lesions rates of 0-83%. Subgroup analysis for studies with (group A, 6 studies, n=1113 cases) and without (group B, 39 studies n=16,741) primary focus on the LFCN lesions was performed. Incidence in group A ranged from 14.8-81% (mean 31%) and 0-83% (mean 3.8%) in group B. The difference between the groups was significant (p=0.005). No uniform and time sensitive definition of postoperative LFCN lesions was found in the literature. An analysis of the publication year and the discovered incidence rate showed an increase of incidence rates [rs=0.521 (p<0.001, two-tailed)] over time.

CONCLUSION

Despite the absence of a uniform definition: LFCN lesions after DAA THA are a frequent and, in the past, often underestimated complication.

LEVEL OF EVIDENCE

IV; systematic review of level II to level IV studies.

Bikini Incision Increases the Incidence of Lateral Femoral Cutaneous Nerve Injury in Direct Anterior Approach Hip Arthroplasty: A Prospective Ultrasonic, Electrophysiological, and Clinical Study

BACKGROUND

Lateral femoral cutaneous nerve (LFCN) injury has been widely reported as one of the most common complications of direct anterior approach (DAA) hip arthroplasty. Bikini incision is considered to increase the incidence of this complication.

METHODS

A prospective randomized study was conducted after including ninety-nine bikini and ninety-six longitudinal incision DAA cases from May to November 2020. The occurrence of LFCN was examined using ultrasound before and after surgery. The recovery of injury symptoms was evaluated by continuous clinical follow-up until six months, and the patients were treated with mecobalamin and/or celecoxib. Sensory conduction velocity and sensory action potential amplitude of the LFCN were measured after surgery in symptomatic patients.

RESULTS

Eighty five (43.6%), sixty seven (34.4%), and forty three (22.0%) cases of LFCN were of the anterior trunk, posterior trunk, and fan types, respectively, before surgery. All one hundred ninety five patients completed the follow-up period. Fifty-seven patients had symptoms of LFCN injury, including thirty six and twenty one patients in the bikini group and longitudinal group, respectively, with significantly different incidence rates (36.4% and 21.9%, respectively; P < .05). Of these, thirty two (56.1%), thirteen (22.8%), and twelve (21.1%) cases were of the anterior trunk, posterior trunk, and fan types, respectively. Sensory conduction velocity and sensory action potential amplitude significantly decreased after surgery in both groups (P < .05). Seventeen cases showed reduction of symptoms within three months. Forty six cases showed self-recovery within six months and eleven cases showed persistent symptoms at the final follow-up.

CONCLUSION

Bikini incision DAA hip arthroplasty may increase the incidence of LFCN injury, and the anterior trunk distribution type is most likely to be affected. (Clinical Trial Registration Number: CHICTR2000035107).

The 2-2-2-20-20 concept for supraacetabular schanz screw insertion without additional radiography

PURPOSE

Application of supraacetabular Schanz screws is usually performed under image intensifier guidance. The aim of this study was to perform it without imaging, with the hypothesis that, respecting anatomical landmarks, pre- and intraoperative fluoroscopy can be avoided.

MATERIAL & METHODS

Insertion of the supra-acetabular Schanz screws was performed by two trauma surgery residents in a study sample of 14 human adult cadavers which had been embalmed by use of Thiel`s method. With cadavers placed in supine position, the anterior superior iliac spine (ASIS) was palpated. Starting from this landmark, 2 cm were measured in a distal and 2 cm in the medial direction. At this point, a 2 cm long oblique skin incision was performed. Through this approach, 150 mm Schanz screws were drilled bilaterally into the supra-acetabular corridor with an angulation of 20° to distal as well as 20° to medial. Following screw application, combined obturator oblique-outlet views (COOO) were taken bilaterally in each specimen by use of an Arcadis© Orbic 3D C-arm to prove the screw position. Six of the specimens underwent a 3D-CT-scan. Images were evaluated concerning correct screw positioning by a further traumatologist. Skin and subcutaneous tissues were removed in the ilioinguinal region and possible lesions to the lateral femoral cutaneous nerve (LFCN) or to the joint capsule were evaluated.

RESULTS

The sample consisted of eight pelves from female and six pelves from male cadavers. During radiographic evaluation of the COOO-scans (14 specimens) and the 3D-scans (6 specimens), the Schanz screws were placed inside the supra-acetabular corridor in all specimens (14/14). During dissections, no intracapsular screw placements or LFCN lesions were found.

CONCLUSION

According to the described anatomical data, we defined a 2-2-2-20-20 concept, starting with a 2 cm skin incision 2 cm distal and 2 cm medial to the ASIS with a drill angulation of 20° inferior and 20° lateral orientation. Using this technique, all Schanz screws could be sufficiently inserted without intraprocedural x-ray imaging.

Treatment of meralgia paresthetica (Lateral Femoral Cutaneous Neuropathy): A meta-analysis of ultrasound-guided injection versus surgery

PURPOSE

To compare ultrasound (US)-guided injections and surgery for the treatment of meralgia paresthetica (lateral femoral cutaneous neuropathy).

METHODS

Two reviewers, independently, up to 10 October 2020 retrieved Studies that assessed the outcome of US-guided injections and surgery for the treatment of meralgia paresthetica from major medical libraries. Predefined inclusion and exclusion criteria were adopted.

RESULTS

399 studies were initially found, and the meta-analysis was conducted on 10 studies for a total of 149 patients. US-guided injections were done in three studies, surgery in seven studies. N = 38 % (57/149) of patients were treated with US-guided injection and 62 % (92/149) were treated with surgery. After US-guided injections, 85 % (49/57) of patients were treated successfully, whereas 80 % (74/92) were treated with surgery successfully from the clinical point of view. Differences were not statistically significant even with a slight heterogeneity of studies and outcome pooled on random-effect model. No comparative cohort study or RCT was conducted.

CONCLUSION

This meta-analysis showed that there was no statistically significant difference in treatment of meralgia paresthetica with ultrasound-guided injection or surgery. A RCT to compare a standardized US-guided approach versus surgery is essential to compare these techniques properly.

Lateral Femoral Cutaneous Nerve Radiofrequency Ablation for Long-term Control of Refractory Meralgia Paresthetica

BACKGROUND

Meralgia paresthetica is a term used to describe a clinical pain syndrome related to the compression or irritation of the lateral femoral cutaneous nerve (LFCN). The LFCN is a pure sensory nerve that is susceptible to compression injury. The most common compression locations are: as it courses from the lumbosacral plexus, through the abdominal cavity, under the inguinal ligament, and into the subcutaneous tissue of the thigh.

METHODS

This case series is a retrospective single-center review of six patients with medically intractable meralgia paresthetica who were treated with radiofrequency ablation. To be considered for radiofrequency ablation, the patient must have been unsuccessful with medical management alone for more than two months and have a clinical diagnosis of meralgia paresthetica. Temporary relief of pain of 50% or greater was considered a positive result. Average pain scores were measured pre- and postprocedure, along with one-, two-, three-, and six-month intervals postoperation.

RESULTS

All patients demonstrated immediate relief in self-reported pain scores, averaging a 75.5% reduction in pain. At the one-, two-, three-, and six-month follow-ups, patients averaged a reduction of 60.0%, 58.0%, 51.4%, and 40.5%, respectively. Both the postop and one-month follow-up pain scores were lower, statistically significantly so (P < 0.05), whereas the two-, three-, and six-month follow-ups were not statistically different from pretreatment scores.

CONCLUSIONS

Although our study was small, radiofrequency ablation showed a clear reduction in average pain scores in a subset of patients who had failed standard medical therapy with a reduction in pain at one-month follow-up with relief of symptoms sometimes lasting longer than 12 months.

Fine architecture of the fascial planes around the lateral femoral cutaneous nerve at its pelvic exit: an epoxy sheet plastination and confocal microscopy study

OBJECTIVE

Meralgia paresthetica is commonly caused by mechanical entrapment of the lateral femoral cutaneous nerve (LFCN). The entrapment often occurs at the site where the nerve exits the pelvis. Its optimal surgical management remains to be established, partly because the fine architecture of the fascial planes around the LFCN has not been elucidated. The aim of this study was to define the fascial configuration around the LFCN at its pelvic exit.

METHODS

Thirty-six cadavers (18 female, 18 male; age range 38-97 years) were used for dissection (57 sides of 30 cadavers) and sheet plastination and confocal microscopy (2 transverse and 4 sagittal sets of slices from 6 cadavers). Thirty-four healthy volunteers (19 female, 15 male; age range 20-62 years) were examined with ultrasonography.

RESULTS

The LFCN exited the pelvis via a tendinous canal within the internal oblique-iliac fascia septum and then ran in an adipose compartment between the sartorius and iliolata ligaments inferior to the anterior superior iliac spine (ASIS). The iliolata ligaments newly defined and termed in this study were 2-3 curtain strip-like structures which attached to the ASIS superiorly, were interwoven with the fascia lata inferomedially, and continued laterally as skin ligaments anchoring to the skin. Between the sartorius and tensor fasciae latae, the LFCN ran in a longitudinal ligamental canal bordered by the iliolata ligaments.

CONCLUSIONS

This study demonstrated that 1) the pelvic exit of the LFCN is within the internal oblique aponeurosis and 2) the iliolata ligaments form the part of the fascia lata over the LFCN and upper sartorius. These results indicate that the internal oblique-iliac fascia septum and iliolata ligaments may make the LFCN susceptible to mechanical entrapment near the ASIS. To surgically decompress the LFCN, it may be necessary to incise the oblique aponeurosis and iliac fascia medial to the LFCN tendinous canal and to free the iliolata ligaments from the ASIS.

Natural history of lateral femoral cutaneous nerve neuropraxia after anterior approach total hip arthroplasty

AIM:

The aim of this study was to examine the natural history of lateral femoral cutaneous nerve (LFCN) neuropraxia in a previously reported cohort of individuals after direct anterior approach (DAA).

METHODS:

99 patients (107 hips) with LFCN neuropraxia were identified, out of which 82 patients (87 hips) (83.1%) completed functional outcomes questionnaires at mean follow-up of 5.5 years (4.4-6.9 years). 5 patients were excluded from the study due to intra-articular source of pain and/or revision surgery. The total sample was composed of 77 patients (31 total hip replacements and 51 hip resurfacings) and functional outcomes scores were obtained for all patients.

RESULTS:

At average 5.46-year follow-up, 55 patients (60 hips 73%) still reported symptoms of LFCN neuropraxia but their Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were not inferior to those who had resolution for pain, function and stiffness: p values of 0.716, 0.171, and 0.238, respectively. The mean score on visual analogue scale decreased from 2.32 (SD 2.11) to 1.76 (SD 1.99). 1 patient (1.2%) reported his activities were limited by his symptoms.

CONCLUSION:

Although the majority of patients still report symptoms related to LFCN neuropraxia, symptoms do improve over time and there are no functional limitations. Even if LFCN neuropraxia following DAA does not lead to functional limitations, all patients should be made aware in order to alleviate any long-term functional concerns.

Ultrasound Diagnostic and Therapeutic Injections of the Hip and Groin

Hip and groin pain often presents a diagnostic and therapeutic challenge. The differential diagnosis is extensive, comprising intra-articular and extra-articular pathology and referred pain from lumbar spine, knee and elsewhere in the pelvis. Various ultrasound-guided techniques have been described in the hip and groin region for diagnostic and therapeutic purposes. Ultrasound has many advantages over other imaging modalities, including portability, lack of ionising radiation and real-time visualisation of soft tissues and neurovascular structures. Many studies have demonstrated the safety, accuracy and efficacy of ultrasound-guided techniques, although there is lack of standardisation regarding the injectates used and long-term benefit remains uncertain.

Ultrasound-guided supra-acetabular pin placement in pelvic external fixation: description of a surgical technique and results

INTRODUCTION

Pelvic fracture in trauma patients can lead to hemodynamic instability. External fixation is a treatment capable of stabilizing these injuries in the context of damage control surgery. Supra-acetabular pin offers the greater biomechanical stability but requires the use of intraoperative fluoroscopy. The aim of this study was to analyze our results for an ultrasound-guided supra-acetabular pinning.

MATERIAL AND METHODS

Cross-sectional study with cadaveric specimens. Ultrasound-guided pin placement assessed by fluoroscopy and dissection.

RESULTS

Fourteen ultrasound-guided supra-acetabular pins were placed in seven cadaveric specimens. Excellent placement in all cases, evaluated with radiological control. Good qualitative bone fixation after dissection. One femoral cutaneous nerve was not found during anatomic dissection and was assumed injured.

CONCLUSION

Ultrasound-guided supra-acetabular pin placement is a feasible and effective technique. Our study indicates that pin placement without intraoperative fluoroscopy is feasible without compromising the reliability of its placement.

Prospective comparison of the anterior and lateral approach in hemiarthroplasty for hip fractures: a study protocol

Background

The Direct Anterior Approach (DAA) is an alternative approach to the currently most used Lateral Approach (LA) for hip replacement in femoral neck fracture patients. Compared to the LA, the DAA minimizes soft tissue damage. Sparing muscle tissue may facilitate early and improved postoperative mobility. It may also be associated with fewer complications, increased quality of life and lower 1-year mortality. The aim of this study is to compare postoperative complications, hip function and patient mobility after hemiarthroplasty via the anterior or lateral approach following a displaced femoral neck fracture.

Methods

138 elderly patients with displaced femoral neck fractures will be operated using either the direct anterior approach or the lateral approach for a hemiarthroplasty in a single centre, prospective, comparative cohort study. The choice of surgical approach will depend on the expertise of the trauma surgeon on call. The primary outcome of this study will be the functionality of the hip after surgery measured using the Harris Hip Score during routine outpatient check-ups. Secondary outcomes include surgical and non-surgical complication rates, admission time, postoperative pain, rehabilitation time, performance in activities of daily living, health-related quality of life measured, cognitive function and balance.

Discussion

Many approaches are known for hip replacement arthroplasty in trauma patients with little consensus on the preferred method. Identifying the best approach facilitating an adequate and fast recovery could optimize patient independence and quality of life and minimize rehabilitation costs, morbidity and mortality rates. The study design will reflect daily clinical practice and aims to present an accurate depiction of clinical outcomes.

Trial registration

This trial entered the Dutch Trial Registry with registration number (NTR)6238 on the 24th of April 2017. http://www.trialregister.nl/trialreg/index.asp. Protocol version 2.0 16–03-2017.

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.

The Anatomical Course of the Lateral Femoral Cutaneous Nerve with Special Attention to the Anterior Approach to the Hip Joint

BACKGROUND

Injury to the lateral femoral cutaneous nerve (LFCN) is a risk during the operative anterior approach to the hip joint. Although several anatomical studies have described the proximal course of the nerve in relation to the anterior superior iliac spine (ASIS) and the inguinal ligament, the distal course of the LFCN in the proximal aspect of the thigh has not been sufficiently studied. The aim of this cadaveric study was to examine the branching pattern of the nerve, with special consideration to the anterior approach to the hip joint.

METHODS

Twenty-eight cadaveric hemipelves from 18 donors (10 paired and 8 unpaired specimens) were dissected. The LFCN branches were localized proximal to the inguinal ligament and traced distally into the area of the proximal aspect of the thigh. Distribution patterns of the nerve with respect to its relationship to the ASIS and the internervous plane of the anterior approach to the hip joint were recorded.

RESULTS

We found 3 different branching patterns of the LFCN: sartorius-type (in 36% of the specimens), characterized by a dominant anterior nerve branch coursing along the lateral border of the sartorius muscle with no, or only a thin, posterior branch; posterior-type (in 32%), characterized by a strong posterior nerve branch; and fan-type (in 32%), characterized by multiple spreading nerve branches of equal thickness. In 50% of the specimens, the LFCN divided into ≥2 branches superior to the inguinal ligament. Sixty-two percent of the LFCN branches entered the proximal aspect of the thigh medial to the ASIS; 27%, above; and 11%, lateral to the ASIS. The LFCN consistently coursed within the deep layer of the subcutaneous fat tissue.

CONCLUSIONS

Injury to branches of the LFCN cannot be avoided in approximately one-third of surgical dissections that use the anterior approach to the hip joint. To protect the anterior branch of the LFCN, the skin incision should be as lateral as possible. The posterior branch of the LFCN is most vulnerable in the proximal aspect of the anterior approach to the hip joint, where it can be expected to course within the deep layer of the subcutaneous tissue.

Local anesthetic injection deep to the fascia iliaca at the level of the inguinal ligament: the pattern of distribution and effects on the obturator nerve

STUDY OBJECTIVE

The femoral, lateral femoral cutaneous, and obturator nerves (ONs) can reportedly be blocked using a single-injection deep to the fascia iliaca (FI) at the level of the inguinal ligament. Two commonly used methods (the FI compartment and 3-in-1 blocks) have produced inconsistent results with respect to local anesthetic distribution and effect on the ON. To date, no study of either method has been performed using advanced imaging techniques to document both needle placement and local anesthetic distribution. We report the outcome of a series of 3-in-1 and FI blocks performed using ultrasound to guide needle position and magnetic resonance imaging (MRI) to define local anesthetic distribution.

DESIGN

Patients were prospectively studied, and images were interpreted using a randomized and blinded protocol.

SETTING

The study was performed in the perioperative area of an academic orthopedic specialty hospital.

PATIENTS

Ten patients (ASA 1-2) having anterior cruciate ligament reconstruction received either 3-in-1 or FI compartment blocks for postoperative analgesia using the surface landmarks described for these techniques.

INTERVENTIONS

Ultrasound was used to position the injecting needle immediately deep to the FI. Local anesthetic distribution was studied using MRI.

MEASUREMENTS

Patients were examined for motor and/or sensory function of the femoral, obturator, and lateral femoral cutaneous nerves. Magnetic resonance imaging was used to document the limits of injectate distribution.

MAIN RESULTS

Magnetic resonance imaging showed distribution of injectate over the surface of the iliacus and psoas muscles to the level of the retroperitoneum. No patient showed medial extension of injectate to the ON. At the level of the inguinal ligament, injectate extended laterally toward the anterior superior iliac spine and medially to the femoral vein. All patients had significant weakness with extension of the knee and sensory loss over the anterior, lateral, and medial thigh. No patient demonstrated decreased hip adductor strength.

CONCLUSIONS

Ultrasound and MRI show consistent superior extension of local anesthetic to the level of the retroperitoneum for both techniques. There was reliable clinical effect on the femoral and lateral femoral cutaneous nerves. However, none of the injections produced evidence of ON block either at the level of the retroperitoneum or the inguinal ligament.

High-resolution 3-T MR neurography of the lumbosacral plexus

The lumbosacral plexus comprises a network of nerves that provide motor and sensory innervation to most structures of the pelvis and lower extremities. It is susceptible to various traumatic, inflammatory, metabolic, and neoplastic processes that may lead to lumbrosacral plexopathy, a serious and often disabling condition whose course and prognosis largely depend on the identification and cure of the causative condition. Whereas diagnosis of lumbrosacral plexopathy has traditionally relied on patients' medical history, clinical examination, and electrodiagnostic tests, magnetic resonance (MR) neurography plays an increasingly prominent role in noninvasive characterization of the type, location, and extent of lumbrosacral plexus involvement and is developing into a useful diagnostic tool that substantially affects disease management. With use of 3-T MR imagers, improved coils, and advanced imaging sequences, which provide exquisite spatial resolution and soft-tissue contrast, MR neurography provides excellent depiction of the lumbrosacral plexus and its peripheral branches and may be used to confirm a diagnosis of lumbrosacral plexopathy with high accuracy or provide superior anatomic information should surgical intervention be necessary.

Meralgia paresthetica: a review of the literature

BACKGROUND AND PURPOSE

Meralgia Paresthetica (MP) is a nerve entrapment which may cause pain, paresthesias, and sensory loss within the distribution of the lateral cutaneous nerve of the thigh. When the differential diagnosis of lateral or anterolateral thigh pain is inconclusive, MP should be considered as a potential source. MP produces similar signs and symptoms as those associated with more common diagnoses such as lumbar spine pathology. This clinical commentary will review the most relevant literature on MP with an emphasis on recognition and management of this condition.

DESCRIPTION OF TOPIC WITH RELATED EVIDENCE

The authors reviewed the most relevant published literature on MP from 1970 to 2013 located using the databases PubMed, CINAHL, and Proquest.

DISCUSSION/RELATION TO CLINICAL PRACTICE

MP still remains a diagnostic challenge since it can mimic other common diagnoses. Understanding the current literature surrounding the diagnosis and treatment of MP is essential for clinicians practicing in the outpatient environment. The consensus on the most effective non-surgical and surgical interventions is still limited, as is the research on physical therapy interventions for this condition. Perhaps the lack of research and global consensus represents a knowledge deficit that makes MP a challenge to diagnose and successfully treat. Future collaborative studies are needed to improve the clinical diagnostics and understanding of interventions for this pathology.

LEVEL OF EVIDENCE

5.

Periacetabular osteotomy for hip preservation

The Bernese PAO has now been performed for nearly 30 years. In that time, it has proved itself a technically complex procedure with the potential to considerably improve the natural history of the dysplastic hip. Significant refinements in the surgical technique combined with the recognition of FAI, improvements in the understanding of hip biomechanics and acetabular orientation, and more discerning patient selection have improved the outcomes related to this procedure. Although the recovery can be demanding and the potential for complications exists, the results are reproducible and the technique has become the gold standard for acetabular reorientation.