Medial Femoral Cutaneous Nerve Research Articles

Medial Femoral Cutaneous Nerve Conduction Study with Distal Stimulation and Recording Technique

Medial Femoral Cutaneous Nerve Conduction Study with Distal Stimulation and Recording Technique

The anterior branch of the medial femoral cutaneous nerve innervates the anterior knee: a randomized volunteer trial.

The midline skin incision for total knee arthroplasty may be an important generator of chronic neuropathic pain. The incision is innervated by the medial femoral cutaneous nerve (MFCN), the intermediate femoral cutaneous nerves (IFCN) and the infrapatellar branch from the saphenous nerve. The MFCN divides into an anterior (MFCN-A) and a posterior branch (MFCN-P). The primary aim was to compare the areas anesthesized by MFCN-A versus MFCN-P block for coverage of the incision. Nineteen healthy volunteers had IFCN and saphenous nerve blocks. The subgroup of volunteers with a non-anesthetized gap between the areas anesthetized by the saphenous and the IFCN blocks was defined as the study group for the primary outcome. Subsequently selective MFCN-A block and MFCN block (MFCN-A + MFCN-P) were performed to investigate the contributions from MFCN-A and MFCN-P to the innervation of the midline incision. All assessments were performed blinded. Ten out of 19 volunteers had a non-anesthetized gap. Nine out of these 10 volunteers had coverage of the non-anesthetized gap after selective anesthesia of the MFCN-A, whereas anesthesia of the MFCN-P did not contribute to coverage of the gap in any of the 10 volunteers. In half of the cases, a gap of non-anesthetized skin was present on the surgical midline incision after anesthesia of the saphenous nerve and the IFCN. This gap was covered by selective anesthesia of the MFCN-A without contribution from MFCN-P. The selective MFCN-A block may be relevant for diagnosis and interventional management of neuropathic pain due to injury of MFCN-A.

Acetabular paralabral cysts demonstrating perineural propagation.

Acetabular paralabral cysts are common and are almost always associated with labral tears. Uncommonly, they extend into the periacetabular soft tissues or may propagate along peripheral nerves causing pain and hip dysfunction. The aim was to evaluate the clinical and MRI presentations of such cases including perineural propagation. Retrospective cross-sectional study with a search of electronic health records for cases of acetabular paralabral cysts demonstrating perineural propagation was performed. Clinical and MR imaging features were tabulated after re-review by experienced musculoskeletal radiologists, and available outcomes were recorded. Descriptive statistics were performed. 14 cases were recorded. The mean age was 56.9 years (range = 30-79 years) and female:male ratio was 1:2.6. The commonest presenting complaint was hip pain (10/14, 71.4%). Other complaints included groin pain, perineal pain and hip dysfunction. No symptoms were attributed to the acetabular paralabral cyst in 3/14 patients (21.4%). None had foot drop. The cysts were multilocular in all cases and were homogenously T2 hyperintense in 13/14 (92.9%). Labral tears were identified in 11/14 cases (78.6%). The sciatic nerve was most commonly involved in 5/14 cases (35.7%) with the obturator, medial femoral cutaneous nerve, femoral nerve, superior and inferior gluteal nerves also affected.No intervention was undertaken in 9/14 cases (64.3%). 5/14 (35.7%) underwent image guided aspiration and corticosteroid injection. 4/5 such patients reported reduced pain following the procedure. Paralabral cysts demonstrating perineural propagation are uncommon and exhibit varied presentations. Most patients who underwent image-guided or surgical interventions reported an improvement in symptoms. This is the first description of a series of patients with acetabular paralabral cysts demonstrating perineural propagation in the literature. A comprehensive description of their clinical and imaging characteristics and interventions/outcomes where relevant is provided.

A novel ultrasound-guided anterior branch of medial femoral cutaneous nerve block.

A novel ultrasound-guided anterior branch of medial femoral cutaneous nerve block.

Medial femoral cutaneous nerve conduction study with distal recording: A novel technique.

A new technique to obtain the sensory nerve action potential (SNAP) of the medial femoral cutaneous nerve is described. SNAPs were recorded from 104 subjects with a bar recording electrode 10 cm proximal to the patella along an imaginary line drawn between the medial edge of the patella and the femoral pulse below the inguinal ligament. Stimulation was applied 14 cm proximal to the recording point. There were 104 healthy subjects. Onset latency of the SNAPs was 2.20 ± 0.16 ms (mean ± SD), peak latency was 2.70 ± 0.16 ms, peak-to-peak amplitude was 7.5 ± 3.0 μV, and conduction velocity was 51.5 ± 3.0 m/s. The side-to-side difference in the mean amplitude was 22.27 ± 13.6%. This new technique is easy, reliable, and reproducible, and should prove useful for the evaluation of neuropathies of the medial femoral cutaneous nerve.

Anesthesia of the anterior femoral cutaneous nerves for total knee arthroplasty incision: randomized volunteer trial

Background and objectivesFor pain relief after total knee arthroplasty (TKA), an injection at the midthigh level may produce analgesia inferior to that of a femoral nerve block as the anterior...

Clinical effects of free superficial femoral artery femoral triangle perforator flap in the repair of skin and soft tissue defects in extremities

Objective: To investigate the clinical effects of free superficial femoral artery femoral triangle perforator flap in the repair of skin and soft tissue defects in extremities. Methods: From January 2016 to November 2017, 14 patients (9 males and 5 females, aged 19 to 54 years) with skin and soft tissue defects in extremities accompanied with tendon and bone exposure were admitted to our unit. The size of skin and soft tissue defects after debridement ranged from 7 cm×3 cm to 10 cm×7 cm. The defects were repaired with free superficial femoral artery femoral triangle perforator flaps, with size ranging from 13.0 cm×2.0 cm to 20.0 cm×4.5 cm. The medial femoral cutaneous nerve was applied to the flap. The perforator flap was grafted onto the medial femoral cutaneous nerve in 6 patients. The donor sites were sutured directly. The survival of flaps and the follow-up of patients were observed. Results: All flaps of 14 patients survived successfully. The recipient sites and donor sites were healed completely in 13 patients, and 1 patient with partial skin necrosis at the edge of flap was healed after treatment. All patients were followed up for 6 months to 1 year after the operation. The flaps were in good shape, with nearly normal color and soft texture and no cicatrix contracture deformity. The flaps recovered protective sense in 6 patients who had medial femoral cutaneous nerve grafting, and the sensory recovery of the flap was slightly worse in the remaining 8 patients. There was no significant complications on the appearance and walking of the donor thigh in 14 patients, only a linear scar was left on the inner thigh, and no numbness was felt in the donor sites of patients. Conclusions: The free superficial femoral artery femoral triangle perforator flap is an ideal therapy for repairing skin and soft tissue defects in extremities.

Novel Demonstration of the Anterior Femoral Cutaneous Nerves using Ultrasound.

Neuropathy of the intermediate (IFCN) and medial femoral cutaneous nerve (MFCN) is a potential iatrogenic complication of thigh surgery and its diagnosis is limited. This study aimed to evaluate the possibility of the visualization and diagnostic assessment of the IFCN and MFCN with high-resolution ultrasound (HRUS). In this study, HRUS with high-frequency probes (15 - 22MHz) was used to locate the IFCN and the MFCN in 16 fresh cadaveric lower limbs. The correct identification of the nerves was verified by ink-marking and consecutive dissections at sites correlating to nerve positions (R1 - 3), namely, the origin, the mid portion, and the distal portion, respectively. 12 cases with suspected IFCN and MFCN lesions referred to our clinic for HRUS examinations were also assessed. Anatomical dissection confirmed the correct identification of the IFCN in 16/16 branches at all of the different locations (100 %). MFCN was correctly identified at R1 + 3, in all cases (16/16; 100 %), and in 14/16 cases (88 %) at (R2). 12 cases of patients with IFCN and MFCN pathologies (all of iatrogenic origin) were identified. 9 instances of structural damage were visible on HRUS, and all pathologies were confirmed by almost complete resolution of symptoms after selective HRUS-guided blocks with 0.5 - 1 ml lidocaine 2 %. This study confirms that the IFCN and the MFCN can be reliably visualized with HRUS throughout the course of these nerves, both in anatomical specimens and in patients.

Morphological study and relations of the fascia vasto-adductoria.

The precise description of the fascia vasto-adductoria (FVA) has become an issue of great surgical and clinical importance. Neurovascular entrapment within the adductor canal (AC) may simulate many clinical conditions for cases presented with medial knee or leg pain and ischemic manifestations of the leg. The aim of the present work is to describe the morphological features of the FVA and to elucidate its neurovascular relations. Forty thigh specimens, pertaining to 15 embalmed and five fresh adult human cadavers, were dissected in pursuit of this aim. The FVA was a continuous subsartorial fascia, roofing the whole length of AC and extended between two points lying at a mean distance of 25.6 and 7cm proximal to the base of patella. It was subdivided into two parts; proximal thin quadrangular (proximal part of FVA) and distal thick pentagonal (vastoadductor membrane; VAM) and the subsartorial space was observed superficial to it. The mean length of its proximal and distal parts was 7.8 and 7.9cm, respectively. The proximal part of FVA, while stretched across the vastus medialis (VM) and the adductor longus (AL) muscles, became attached to the wall of the femoral artery and overlaid the femoral vessels, the saphenous nerve (SN), and an arterial pedicle for VM muscle. It was constantly pierced by two arterial pedicles arising from the femoral artery to the sartorius muscle and occasionally (50%) by a communicating nerve branch arising from the SN to join the medial femoral cutaneous nerve. The VAM stretched across the VM muscle and boththe AL andadductor magnus (AM) muscles and overlaid the SN, its subsartorial and lower medial femoral cutaneous branches, femoral vessels, 1-3 arterial pedicles for the sartorius and descending genicular vessels. The VAM originated from the tendinous fibres of the AM tendon and constantly spread anterolaterally. It was constantly pierced by 1-3 arterial pedicles to sartorius muscleand both the lower medial femoral cutaneousbranch and the subsartorial branches of the SN. An arterial pedicle to the VM muscle and perforating veins between the superficial veins and the femoral vein proved to pierce it in 8/40 specimens. Entrapment of the SN at the distal narrow aperture of the AC, or one of its cutaneous branches at the piercing sites of the FVA, should be remembered when diagnosing cases presented with medial knee or leg pain. The attachment of the proximal part of the FVA to the wall of the femoral artery could add to the mechanism of its potential compression. True AC block should be done deep to the FVA to ensure effective SN analgesia. Its site is recommended to be at the distal one cm of the proximal part of the AC which is at a distance of 16-17cm proximal to the base of patella. The VAM, being an anatomical connection between the VM and AM muscles, is theorized to increase the mechanical efficiency of the VM oblique muscle to maintain the knee extensor mechanism.

Repairing of limb extremity wounds with free descending genicular artery perforator flap without saphenous vein

Objective To explore the surgical technique and the efficacy of free descending genicular artery perforator flap without saphenous vein for tissue defect. Methods 18 cases of extremity tissue defect were involved in this study from August 2010 to April 2014, including 16 males and 2 females with an average age of 32.4 years (8 plantar or heel soft tissue defect, 10 back of hand or palm soft tissue defect). 2 old injury cases that had soft tissue defect after scar release were treated by free flaps and the other 16 were open injury with infection, among which 5 cases were combined with fractures or bone defect. Sizes of the skin and soft tissue defect were 2.0 cm×8.0 cm to 9.0 cm×12.0 cm. All wounds were treated by free descending genicular artery perforator flap from the contralateral limb. Medial femoral cutaneous nerve was kept in flaps as far as possible. The projection points of descending genicular artery perforator and saphenous vein were detected by Doppler, then the flaps were cut with reverse approach, and saphenous vein and saphenous nerve were preserved. Results All 18 flaps were survived and all cases were followed up for 3 to 30 months (average, 10.3 months). The flap sizes varied from 2.5 cm×9.0 cm-9.5 cm×13.0 cm. 2 cases with bone defect were healed 3 months later without infection, and the other 3 cases with fractures were healed 2-3 months after operation. The two point's discrimination distance was 7.0-12.0 mm on the flap. The disabilities of the arm, shoulder, and hand questionnaire score averaged 51, and the mean Japanese Orthopaedic Association's foot rating scale was 70.5. Most patients were satisfied with appearance of the recipient and donor sites, among which 5 cases had skin-graft on the donor sites, and the other 12 cases had small scars on the donor sites. Poor healing was detected in 1 case on the thigh which was healed 3 weeks later. There was no paresthesia and rash on the donor sites. The mean distance between projection points of descending genicular artery perforator and saphenous vein was 3.7 cm. Conclusion Free descending genicular artery perforator flap without saphenous vein is an optimal therapy for the extremity tissue defect, which has the advantage of covert donor site, less invasion, less variation of perforator, and could recover the skin sense of recipient site. Key words: Surgical flaps; Wounds and injuries; Extremities

Multibranch anastomotic variant of the Lateral Femoral Cutaneous Nerve: possible implications in neurosurgical practice

Dear Editor, The anatomy and topography of the lateral femoral cutaneous (LFCN) and genitofemoral (GFN) nerves is known to have some variability [6]. Their formation and distribution may complicate the outcome of several surgical procedures, such as extraperitoneal approaches to the anterior and lateral lumbar spine [1, 2], rendering these nerves more vulnerable to iatrogenic injury. During a routine dissection of a formalin-fixed, 78-yearold male cadaver, a variant left LFCN was encountered. In the pelvis, the LFCN originated from the L2/L3 roots and emerged typically from the lateral border of the psoas major (PM) muscle. The nerve gave off a lateral accessory LFCN and a medial accessory anterior femoral cutaneous nerve branch, at 5.6 cm and 7.2 cm from the lateral border of the PM muscle, respectively. The GFN, after penetrating the PM muscle, branched off at 3.4 cm prior to the inguinal ligament (IL), providing a lateral nerve that anastomosed with the two LFCN branches below the IL level (Fig. 1a). The three nerve branches passed separately behind the IL and anastomosed 1.1 cm below the IL level, creating a multibranch octopus-like formation that eventually gave off six terminal nerve branches providing sensory supply to the anterolateral thigh (Fig. 1b). Both GFN and LFCN constitute branches of the lumbar plexus [6]. In GFN neuropathy, the symptomatology includes sensory loss and paresthesia over the GFN distribution area. In our case, the GFN anastomosed with the LFCN below the IL level; thus GFN neuralgia may present with sensory abnormalities such as numbness in the anterolateral and lateral thigh. LFCN injury leads to “meralgia paresthetica”, a disorder presenting with paresthesia and numbness over the LFCN supplied area [4]. The IL constitutes a potential entrapment site; in our case, three nerve branches passed behind the IL, jeopardizing nerve traction and neuropathy, leading to increased risk of producing such symptoms. Surgical treatment of “meralgia paresthetica” mainly includes nerve decompression or neurolysis and transposition of the trapped nerve branch [5]. Neurectomy can be also done in cases where other surgical treatments have failed [3]. The presence of multiple nerve branches passing behind the IL may provoke recurrence of symptoms if the surgeon does not identify the responsible nerve branch, although this multinerval supply may be useful in preserving sensation in the affected area after resection of the injured branch. Both LFCN and GFN can be injured during a lateral retroperitoneal approach to the lumbar spine [1, 2]. It is also challenging to recognize possible variants in surgery. Due to the fact that their activity is difficult if not impossible to be monitored reliably with neurophysiology intraoperatively, this type of injury usually remains unnoticed during surgery, with patients complaining for thigh numbness postoperatively [2]. Fortunately, the symptoms tend to resolve within weeks. G. K. Paraskevas :K. Natsis :M. Tzika Department of Anatomy, Faculty of Medicine, Aristotle University, Thessaloniki, Greece

Clinical utility of sensory nerve conduction of medial femoral cutaneous nerve

In this investigation we report on the clinical utility of sensory nerve conduction studies of the medial femoral cutaneous (MFC) nerve. Sensory nerve conduction of the MFC nerve was assessed in 22 patients for whom this test was considered clinically necessary. MFC nerve conduction was abnormal in 4 cases of MFC neuropathy. The most common cause was iatrogenic in 14 femoral neuropathy cases. MFC nerve conduction showed absent or low-amplitude sensory nerve action potential (SNAP) in 13 cases, with femoral motor nerve conduction abnormal in 5 cases. In 2 cases with acute lumbar plexopathy, the MFC SNAP was absent unilaterally. MFC nerve conduction was normal in 1 case with diabetic lumbar radiculopathy and in another case with postpolio syndrome. Assessment of MFC nerve conduction is extremely useful in the diagnosis of femoral neuropathy, medial femoral cutaneous neuropathy, and lumbar plexopathy.

Use of the Medial Side of the Knee Skin as a Free Flap: Saphenous Flap

The knee region is a good free skin flap donor site, as it has minimal subcutaneous tissue and provides a hidden donor site. Acland et al. first used the skin over the medial side of the knee as a "saphenous flap" based on the saphenous branch of the descending genicular artery. The authors studied the descending genicular artery and its saphenous branch in six cadaver limbs and elevated the skin over the medial side of the knee as a free flap in six patients to reconstruct lower extremity defects. In all clinical cases, the authors were able to elevate a skin flap from the skin on the medial side of the knee. The saphenous branch was absent in one cadaveric limb and one patient limb; instead, a direct cutaneous branch from the femoral artery reached the skin and had nearly the same caliber as the saphenous branch of the other cases. All the flaps survived and the defects healed well. The medial side of the knee is a good donor site, as it provides thin skin with innervation potential by means of the medial femoral cutaneous nerve and leaves an inconspicuous donor-site scar.

Anatomical bases for minimizing sensory disturbance after arthroscopically-assisted anterior cruciate ligament reconstruction using medial hamstring tendons.

The aim of this study was to improve surgical techniques for arthroscopically-assisted anterior cruciate ligament (ACL) reconstruction with minimal sensory disturbance in the infrapatellar and anterior lower leg regions. Thirteen patients with sensory disturbance were examined neurologically, and 51 lower limbs of 26 adult cadavers were examined anatomically to investigate the nerve branches supplying the regions. The region of sensory disturbance was supplied by branches of the medial femoral cutaneous nerve and the saphenous nerve, and the nerves showed a complementary distribution area. After detailed investigation of the positional relationships between the nerve branches and the skin incisions of the operative procedure, it was found that at least one branch of both nerves ran across the longitudinal skin incision (80%) for tendon harvest in the above-mentioned reconstruction. The complicated anatomic variations of the nerve branches preclude their absolute avoidance in any surgical incision, and a completely safe zone could not be found in the present study. However, an oblique incision for the tendon harvest rather than the typical longitudinal incision should be considered to minimize the sensory disturbance.

Medial femoral cutaneous nerve conduction.

Medial femoral cutaneous nerve (MFCN), a sensory branch of the femoral nerve, supplies the skin on the anterior medial aspect of the thigh and knee. A conduction study for this nerve is described. A recording electrode was placed anterior-medially in the thigh and 14 cm distal to the stimulating cathode that was placed immediately lateral to the femoral artery just below the inguinal ligament. Sixty-four nerves of 32 adults with a mean age of 40 yr (range, 21-56) were tested. The latencies to the onset and peak were 2.4 +/- 0.2 and 2.9 +/- 0.2 ms, respectively. The amplitude of baseline to negative peak was 4.9 +/- 1.0 microV. The conduction velocity calculated by the distance divided by the onset latency was 60 +/- 5 m/s. We conclude that the MFCN is accessible for electrophysiologic evaluation, which may help in diagnosing the MFCN or femoral neuropathy.

Guidance of regenerating motor axons in larval and juvenile bullfrogs

The segmental distribution of regenerating bullfrog motor axons was mapped in advanced tadpoles and juvenile frogs by stimulating selected muscle nerves and recording from the distal ends of the 3 lumbar ventral roots (VRs) that innervate the hindlimb. When motoneurons were axotomized by VR transection, they reestablished their original innervation fields, rarely, if ever, growing beyond the territory normally supplied by their spinal segment. However, when motoneurons were axotomized in the spinal nerves at the level of the hindlimb plexus, some of them regenerated into limb nerves that lay outside the axons' normal segmental boundaries, and many regenerated into the medial femoral cutaneous nerve, a pathway normally limited to sensory axons. These observations suggest that the ultimate destinations of regenerating axons are largely determined by structures the axons encounter as they penetrate the distal nerve stumps. Thus, axons regenerating from a severed VR grow into that root's own distal stump and reinnervate the hindlimb in a manner that is segmentally appropriate; axons transected near the plexus have access to the pathways of sensory, as well as motor, axons in all 3 lumbar segments, and establish innervation fields that are inappropriate for their segment of origin and their motor function.

Two New Cutaneous Free Flaps: The Medial and Lateral Thigh Flaps

Two new cutaneous free-flap donor areas are described on the medial and lateral sides of the thigh. The medial thigh flap is supplied by an unnamed artery from the superficial femoral artery and is drained by the accompanying venae comitantes. Its nerve supply is from the medial femoral cutaneous nerve. The lateral thigh flap has its vascular pedicle from the third perforating artery of the profunda femoral artery and its accompanying vein. The lateral femoral cutaneous nerve provides sensation over the area. These flaps provide a large surface area of both skin and subcutaneous tissue without the usual bulk of subcutaneous fat and muscle. Their desirable features include long vascular pedicles with large vessel diameters and potential of being neurovascular flaps with specific sensory nerve supply and predictable anatomy. The principal disadvantage is that the donor site may leave a slight contour defect with primary closure or require grafting when a large flap is taken. We predict that these flaps will become important donor sites for reconstructive problems requiring resurfacing of cutaneous defects in various anatomic areas.