Cutaneous Nerve Research Articles

Characterization of the Posterior Femoral Cutaneous Nerve and Its Clinical Application for Autologous Breast Reconstruction

IntroductionAutologous breast reconstruction (ABR) uses a harvested tissue flap from the abdomen, posterior thigh, or buttocks to rebuild the breast postmastectomy. Identification of nerves for use in autologous sensate breast reconstruction flaps is an important surgical consideration as loss of breast sensation is a common risk of ABR. The posterior femoral cutaneous nerve (PFCN) and its branches supply sensory innervation to skin of the posterior thigh, leg, perineum, and buttocks, creating a feasible candidate for sensate profunda artery perforator (PAP) flaps for reestablishing breast sensation through ABR. This study characterized PFCN perforating branches located within the PAP flap region as compared to an anatomical landmark intersection (ALI). Twenty-three posterior thigh regions from 15 formalin-embalmed donors were dissected to the level of deep fascia to identify PFCN branches. PFCN branch diameter (mean, 1.34 ± 0.35 mm) and length (mean, 8.82 ± 5.78 mm) piercing the deep fascia were measured; branches were retro-dissected proximally to the PFCN trunk and the distance recorded (mean, 92.55 ± 38.00 mm). The distance to branch emergence from ALI (mean, 113.55 ± 19.80 mm) and from the midline of the posterior thigh (mean, 18.90 ± 11.17 mm) were calculated. Two-Tailed T-tests comparing the left and right limb of 7 donors determined bilateral, statistically significant difference between the length of branch emergence back to the main trunk of PFCN (P = .00). These findings illustrate the presence of adequate yet variable PFCN branches within the PAP flap region in regards to diameter, length, and location for use in sensate ABR.

Sihler's Staining of the Thoracic Cutaneous Nerve and its Significance

Sihler's Staining of the Thoracic Cutaneous Nerve and its Significance

Innervation of thumb carpometacarpal joint: implications for diagnostic block and denervation procedures

IntroductionOsteoarthritis (OA) of the thumb carpometacarpal (CMC) joint is a common disorder that negatively impacts hand function. Denervation of the thumb CMC joint has emerged as a viable treatment option....

Comparison of analgesic efficacy of combined external oblique intercostal and rectus sheath block with local infiltration analgesia at port site in patients undergoing laparoscopic cholecystectomy: a randomized controlled trial.

Conventional fascial plane block approaches for upper abdominal surgeries spare the lateral cutaneous nerve. An external oblique intercostal block (EOIB) may be suitable for upper abdominal incisions as it blocks the lateral and anterior branches of the intercostal nerves T6-T10. However, there is a paucity of studies evaluating this block in clinical settings. The study aimed to compare the analgesic efficacy of combined EOIB and rectus sheath block with local infiltration analgesia (LIA) in laparoscopic cholecystectomy (LC). After obtaining written informed consent, 70 patients were randomly allocated to undergo right-sided EOIB with 20 ml and left-sided RSB with 10 ml of 0.25% bupivacaine at the end of surgery (group ER, n = 35). Patients in the LIA group (n = 35) underwent local infiltration at the port site using 20 ml of the same solution (group LIA, n=35). The visual analog scale scores with combined EOI and RSB were significantly lower than those with LIA at 1, 2, 4, 8, and 12 h (P < 0.001). Rescue analgesics were required by 65.7% and 14.3% of the patients in the LIA and block groups, respectively (P < 0.001). The time to first rescue analgesic was significantly greater in the ER group than that in the LIA group (2.8 ± 1.10 vs. 1.6 ± 0.50 h; P = 0.012). The number of times rescue analgesia was required was significantly lower in the ER group than that in the LIA group (1.00 ± 0.00 vs. 1.83 ± 0.72; P = 0.015). Nausea and vomiting scores were higher in the LIA group than those in the ER group (P < 0.001). Patient satisfaction scores were higher in the ER group than those in the LIA group. EOIB combined with RSB provides superior analgesia compared with LIA and should be considered for LC.

Challenges and Advances in the Diagnosis and Management of Neurogenic Thoracic Outlet Syndrome: A Comprehensive Review.

Neurogenic thoracic outlet syndrome (nTOS) is caused by brachial plexus compression in the thoracic outlet. It accounts for 85%-95% of thoracic outlet syndrome (TOS) cases, which may also be caused by compression of the subclavian artery and vein. Compression occurs in the interscalene triangle, costoclavicular space or subpectoralis minor space, with congenital anomalies and repetitive overhead activities as contributing factors. Diagnosis is challenging due to overlapping symptoms with other conditions. Patients commonly report pain, numbness, tingling and weakness in the neck, shoulder and arm, exacerbated by arm elevation. Symptoms related to nTOS may manifest in the distribution of the upper (C5-C6), middle (C7) and lower plexus (C8-T1). Although widely used, provocative tests have varying degrees of sensitivity and specificity and may have high false-positive rates, complicating the diagnosis. Patterns on electrodiagnostic studies provide key diagnostic clues, such as reduced sensory response in the medial antebrachial cutaneous nerve and low compound motor action potential in the median nerve. Imaging techniques like magnetic resonance imaging (MRI), alongside procedures like diagnostic and therapeutic anterior scalene blocks, assist in identifying anatomical abnormalities and predicting surgical outcomes. Management of nTOS involves lifestyle changes, physical therapy, medication and botulinum toxin injections for symptomatic relief. Surgical options may include supraclavicular, transaxillary and infraclavicular approaches, each offering specific benefits based on patient anatomy and surgeon expertise. Minimally invasive techniques, such as video-assisted thoracoscopic surgery (VATS) and robotic surgery, enhance exposure and dexterity, leading to better outcomes. Future research should focus on developing precise diagnostic tools, understanding nTOS pathophysiology, standardising diagnostic criteria and surgical approaches, comparing long-term treatment outcomes and exploring preventive measures to improve patient care and quality of life. Level of Evidence: Level V (Therapeutic).

Comparison of Pericapsular Nerve Group and Lateral Quadratus Lumborum Blocks for Analgesia after Primary Total Hip Arthroplasty: A Randomized Controlled Trial.

The quadratus lumborum block (QLB) and the pericapsular nerve group (PENG) block both provide effective postoperative analgesia after hip surgery while minimizing impact on motor function. This study aimed to compare QLB and PENG in patients undergoing primary total hip arthroplasty. This superiority trial randomized patients scheduled for elective total hip arthroplasty to receive a lateral QLB or PENG with lateral femoral cutaneous nerve blocks for postoperative analgesia. Perioperative analgesic protocols were standardized. The primary outcome was postoperative cumulative opioid consumption at 72 hours. Secondary outcome was postoperative pain scores. Additional outcomes of interest included time to first ambulation, length of stay, patient reported outcome measures, and opioid-related side effects. This trial consented and randomized 106 subjects and 101 were included in analysis: PENG (n=50), QLB (n=51). Mean (95% CI) opioid consumption (IV MME) in the first 72 hours did not differ between PENG [109.6 (93.6, 125.6)] and QL [92.3 (76.6, 107.9)] groups (p=0.129) There were no significant differences between treatment arms in average pain score, time to ambulation, distance ambulated, rate of same day discharge, or hospital length of stay. There were also no differences in patient reported outcomes using HOOS-JR and PROMIS-10 scores. Patients undergoing primary THA receiving preoperative PENG vs QLB had similar opioid consumption, pain scores, time to ambulation, and hospital length of stay. Both QL and PENG blocks are analgesic options in patients undergoing primary THA. NCT05710107; www.ClinicalTrial.gov IRB Protocol ID: Pro00124880. Pericapsular nerve group (PENG) block may provide analgesia after hip arthroplasty and improve early functional recovery. This study evaluated postoperative opioid consumption in patients randomized to PENG or lateral quadratus lumborum block (QLB).Opioid consumption, pain scores, motor recovery, and functional outcome measures did not differ in patients randomized to PENG vs lateral QLB.PENG and lateral QLBs are analgesic options following total hip arthroplasty with similar rates of same day discharge.

An earthquake reality: fasciotomy wounds and treatments

Earthquake-induced Crush Syndrome and subsequent acute kidney injury are important issues that affect morbidity and mortality. Fasciotomies prolong the length of stay in intensive care unit in patients with Compartment Syndrome due to the complications it causes. Infections and delayed wound healing are two common complications among these. Therefore, early closure of fasciotomy wounds is recommended. Although different treatments can be applied for treatment of wounds, data on this subject in pediatric patients are insufficient. We report the case of a 15-year-old girl who developed acute renal failure due to crush syndrome after being trapped in the wreckage for 9 hours and undergoing fasciotomy procedures for four locations, in the left extremity, two in the thigh and two in the cruris. Hemodialysis, antihypertensive, and antibiotic treatment were administered during the intensive care follow-up due to acute kidney injury, hypertension, and sepsis. With negative pressure therapy, silver alginate wound dressing, and hyperbaric oxygen therapy, all wounds epithelialized within two months. However, rehabilitation for drop foot syndrome caused by nerve cuts in the left extremity continues.

A cross‐sectional study of anterior cutaneous nerve entrapment syndrome at a Japanese emergency department

AbstractBackgroundAnterior cutaneous nerve entrapment syndrome (ACNES) is the most common cause of abdominal wall pain. This study aimed to clarify the proportion of ACNES cases among those of abdominal pain and the clinical characteristics and prognosis of the disease in an emergency department (ED) of a Japanese general hospital.MethodsThe medical records of patients from January 2014 to December 2023 were reviewed, and patients aged 15 years or older with abdominal pain with positivity for Carnett's sign, a good response to trigger point injection (TPI), and an ACNES diagnosis were included. The proportion of ACNES cases among the complaints related to abdominal pain in the ED between 2020 and 2023 was then determined. The recurrence rate was also determined using data from the medical records and telephone follow‐ups.ResultsTwenty‐one patients were included. Their median age was 50 years (range: 16–83 years), 13 (62%) were female, and 11 (52%) had acute‐onset pain. Follow‐up data were available for 11 patients (52%), seven (64%) of whom had recurrent pain for a median period of 1 week after the index visit. The proportion of ACNES cases among those of abdominal pain was 0.11%.ConclusionACNES might be uncommon among patients with abdominal pain in the ED setting although underdiagnosis of this condition might have led to an underestimation of the proportion of cases. Moreover, given the high recurrence rate of abdominal pain associated with ACNES, following up these patients is very important.

Ultrasound-Guided Percutaneous Cryoneurolysis of the Antebrachial Cutaneous Nerves for the Management of Prolonged Acute Post-Surgical Forearm Pain: A Report of Two Cases.

Prolonged acute postsurgical pain (PAPSP) contributes to the development of chronic postsurgical pain, impaired rehabilitation, longer hospital stays, and decreased quality of life. For upper extremity analgesia, the duration of postoperative pain management with continuous brachial plexus peripheral nerve blocks is limited due to the risk of infection. Ultrasound-guided percutaneous cryoneurolysis provides extended analgesia and avoids the risks and inconveniences of indwelling catheters. We present 2 cases of PAPSP of the forearm effectively managed by the use of ultrasound-guided percutaneous cryoneurolysis to treat the medial, lateral, and posterior antebrachial cutaneous nerves.

Variations in origin and relation of the posterior cutaneous nerve of the thigh with piriformis muscle

Variations in origin and relation of the posterior cutaneous nerve of the thigh with piriformis muscle

Changes in the Cutaneous Nerve Fiber Staining and Distribution of PGP9.5 in Clinically Uninvolved Skin in Leprosy Patients after Completion of Multidrug Therapy and Assessing PGP9.5 as a Marker of Treatment Response.

Subclinical involvement of nerves may sometimes be present much before the overt clinical manifestations become apparent. Protein gene product (PGP) 9.5, a ubiquitin-C-terminal hydrolase, has been widely used as a marker to study the involvement of peripheral nerve fibers in many diseases. To evaluate the change in cutaneous nerve fiber staining and distribution from pre-treatment and post completion of multidrug therapy through the expression of PGP9.5 and to assess PGP9.5 as a marker of treatment response. In this prospective single-center observational study, skin biopsy was taken in patients with leprosy, having areas of nerve function impairment (NFI), based on findings of nerve conduction studies (NCSs), but not having lesions or impaired tactile or thermal impairment clinically. The thin nerve fiber density in the clinically normal skin in areas supplied by nerve showing changes of sensory neuropathy was evaluated to study the density of the fibers. A second biopsy was taken at the end of treatment from a site near the previous site to assess the changes in intra-epidermal nerve fiber staining and distribution. Thirty-three patients were recruited in the present study (24 males and 9 females). Pre-treatment, 27 patients had abnormal NCSs, while six patients did not have any evidence of neuropathy on NCSs. Staining for nerve fibers using PGP9.5; in the epidermis was positive in five patients pre-treatment and 11 patients post treatment (P = 0.181). Staining in the dermis revealed positivity in 14 pre-treatment, which increased to 18 post treatment (P = 0.342). Adnexae showed positivity in five patients pre-treatment and increased to 17 post treatment (P = 0.005). A reduced PGP9.5 staining in the epidermal, dermal, and adnexal regions was seen in leprosy patients, which improved post treatment. Thus, PGP9.5 may serve as a marker of NFI and treatment response.

Clinical Insights and Optimization of Surgical Approach for Lateral Femoral Cutaneous Nerve Injury/Entrapment: A Comprehensive Analysis of 184 Cases.

Entrapment or injury of the lateral femoral cutaneous nerve (LFCN) is being recognized with increasing frequency, often requiring a surgical approach to relieve symptoms. The presence of anatomic variations can lead to errors in diagnosis and intraoperative decision-making. This study presents the experience of a single surgeon (T.W.T.) in managing 184 patients referred with clinical issues related to the LFCN. A comprehensive review of these cases was conducted to develop a prospective surgical management algorithm. Data on the LFCN's anatomic course, pain relief outcomes, comorbidities, body mass index, and sex were extracted from patients' medical charts and operative notes. Pain relief was assessed subjectively, categorized into "excellent relief" for complete pain resolution, "good" for substantial pain reduction with some residual discomfort, and "failure" for cases with no pain relief necessitating reoperation. The decision tree is dichotomized based on the mechanism of LFCN pathology: compression (requiring neurolysis) versus history of trauma, surgery, and/or obesity (requiring resection). Forty-seven percent of the patients in this series had an anatomic variation. It was found that failure to relieve symptoms of compression often indicated the presence of anatomic variation of the LFCN or intraneural changes consistent with a neuroma, even if adequate decompression was achieved. With respect to pain relief as the outcome measure, recognition of LFCN anatomic variability and use of this algorithm resulted in 75% excellent results, 10% good results, and 15% failures. Twenty-seven of the 36 failures originally had neurolysis as the surgical approach. Twelve of those failures had a second surgery, an LFCN neurectomy, resulting in 10 excellent, 1 good, and 1 persistent failure. This article establishes an algorithm for the surgical treatment of MP, incorporating clinical experience and anatomical insights to guide treatment decisions. Criteria for considering neurectomy may include a history of trauma, prior local surgery, anatomical LFCN variations, and severe nerve damage due to chronic compression.

Anterior cutaneous nerve entrapment syndrome (ACNES) in a Palliative care setting

Anterior cutaneous nerve entrapment syndrome (ACNES) in a Palliative care setting

Superficial retrocalcaneal bursae and nerves: From anatomy to ultrasound‐guided procedures

AbstractThe pertinent literature widely describes ultrasound‐guided procedures targeting the retrocalcaneal bursa and the tendon tissue to manage insertional Achilles tendinopathy. Synovial bursae and cutaneous nerves of the superficial retrocalcaneal pad are often overlooked pain generators and are poorly considered by clinicians and surgeons. A layer‐by‐layer dissection of the superficial soft tissues in the retrocalcaneal region of two fresh frozen cadavers was matched with historical anatomical tables of the textbook Traite d'Anatomie Topographique Avec Applications Médico‐Chirurgicales (1909 by Testut and Jacob). An accurate and detailed description of the superficial retrocalcaneal pad with its synovial bursae and cutaneous nerves was provided. Cadaveric dissections confirmed the compartmentalized architecture of the superficial retrocalcaneal fat pad and its histological continuum with the superficial lamina of the crural fascia. Superficial synovial tissue islands have been demonstrated on the posterior aspect of the Achilles tendon in one cadaver and on the posterolateral surface of the tendon in the other one. Digitalization of the original anatomical tables of the textbook Traite d'Anatomie Topographique Avec Applications Médico‐Chirurgicales (1909 by Testut and Jacob) showed five potential locations of the superficial calcaneal bursa and a superficial retrocalcaneal nerve plexus within the Achilles tendon‐fat pad interface. In clinical practice, in addition to the previously described interventions regarding the retrocalcaneal bursa and the tendon tissue, ultrasound‐guided procedures targeting the synovial and neural tissues of the superficial retrocalcaneal pad should be considered to optimize the management of insertional Achilles tendinopathy.

Assessment of Skin Biopsy as a Diagnostic Biomarker in CSF1R-Related Disorder.

To validate a recently published study in which skin biopsy was reported as a valuable alternative to brain biopsy in diagnosing CSF1R-related disorder (CSF1R-RD). Blinded evaluation of skin samples was performed by independent reviewers using light and electron microscopy collected from a group of CSF1R variant carriers (n = 10) with various genotypes (mono and biallelic), different stages of the disease (asymptomatic and symptomatic), and exposed to different therapies (glucocorticoids, hematopoietic stem cell transplantation, and TREM2 agonist), and from a group of healthy controls (n = 5). Biopsies from patients with CSF1R-RD at various disease stages were indistinguishable from controls determined using light microscopy and electron microscopy. We found no distinctive axonal pathology in skin biopsies collected from CSF1R variant carriers at all stages of the disease. Our results are consistent with clinical and neurophysiologic features of the CSF1R-RD, in that peripheral nervous system involvement has not been reported. Studies aiming to discover new biomarkers are important, but the results must be validated with larger numbers of patients and healthy controls. Based on blinded light and electron microscopic studies of skin biopsies, there is no evidence that CSF1R-RD is associated with distinctive changes in cutaneous peripheral nerves. This suggests that skin biopsy is not useful in diagnosis of CSF1R-RD. This study provides Class III evidence that skin biopsy does not distinguish those with CSF1R-RD, or carriers, from normal controls.

Response to "Pericapsular nerve group block and lateral femoral cutaneous nerve block versus fascia iliaca block for multimodal analgesia after total hip replacement surgery: A retrospective analysis".

Response to "Pericapsular nerve group block and lateral femoral cutaneous nerve block versus fascia iliaca block for multimodal analgesia after total hip replacement surgery: A retrospective analysis".

Anatomy of the Lateral Antebrachial Cutaneous Nerve: Landmarks for Procedures in the Cubital Fossa

The research outlines anatomical landmarks that may help surgeons in identifying the lateral antebrachial cutaneous nerve (LABCN) to minimize nerve damage during procedures in the cubital fossa. Twenty-eight fresh cadaveric upper extremities were dissected. The course of the LABCN was followed from the emerging point at the biceps brachii tendon (BT) to the mid-forearm. The nerve's relationships with the BT, lateral epicondyle (LE), antebrachial vein, and brachioradialis (BR) muscle were measured and documented. The LABCN emerged lateral to the BT in all specimens and crossed medially at the top of the BT in 50% of the cadavers. It was deep to the forearm superficial fascia in all cadavers. At the level of the LE, the nerve was located at a mean of 6.3 ± 3.1 mm medial to the BR. The LABCN aligns with the medial border of the BR at a mean of 68 mm distal to the interepicondylar line. The mean distance from the LE to the LABCN at the interepicondylar line was 24.5 ± 7.2 mm. The LABCN and antebrachial vein are in the same deep fascia plane, on average 47.6 ± 5 mm (37-55) from the LE. At the elbow joint level, 82.1% of the specimens have two branches for the LABCN, whereas 17.9% demonstrated only a single branch. Lateral antebrachial cutaneous nerve was situated approximately 6.8 cm distal to the interepicondyle line, positioned at the ulnar edge of the BR, and runs parallel with the antebrachial vein deep to the forearm fascia plane. The nerve crossed over the biceps tendon in 50% of the specimens. These findings suggest that the nerve should be identified 6-7 cm distal to the LE, followed by a proximal dissection. This study may help surgeons in identifying LABCN, and reducing the potential risk of LABCN injury.

Modified pedicle screw-rod fixation versus open reduction plate fixation for the management of pubic symphysis diastasis: A retrospective study

ObjectiveSurgical intervention and fixation is the recognized measurement to treat pubic symphysis diastasis caused by high-energy trauma. The purpose of this retrospective study was to assess the clinical application of modified pedicle screw-rod fixation (modified PSRF) and open reduction plate fixation (ORPF) for treating pubic symphysis diastasis. MethodsThe data of this retrospective analysis were collected from 32 patients with pubic symphysis diastasis managed with modified PSRF or ORPF from January 2012 to December 2017, with or without posterior fixation. Indicators of clinical assessments including operating time, intraoperative blood loss, relevant surgical complications as well as follow-up were recorded. Majeed scores were performed for functional evaluation, as well as Matta criteria were applied to evaluate the quality of reduction. ResultsThe average time from injury to operation was 2.9 days in modified PSRF group and 3.2 days in ORPF group. Significant differences regarding average operation time (41.8 min versus 64.3 min) and average intraoperative blood loss (46.6 ml versus 304.6 ml) were presented between modified PSRF groups and ORPF group. Neither Majeed scores nor Matta evaluation showed a significant difference between two groups. In ORPF group, the incision infection occurred in one patient and two patients developed loosening of screws. In modified PSRF group, loosening of screws was found in one patient during the operative procedure and one patient experienced femoral nerve palsy. Irritation to the lateral femoral cutaneous nerve (LFCN) was detected in two patients in modified PSRF group. ConclusionsSatisfactory clinical outcomes were provided with applications of both fixation methods for treating pubic symphysis diastasis. Modified PSRF, as a minimal invasive technique, could serve as an effective and reasonable option for treating pubic symphysis diastasis.Level of evidence: III: retrospective cohort study.Trial registration: researchregistry3906.

Neurotized profunda artery perforator flap for subtotal tongue reconstruction – Prospective case series

BackgroundTotal or subtotal glossectomy defects cause significant functional deficits in swallowing and speech and subsequently impair patients’ quality of life. Recently, the profunda artery perforator (PAP) flap has emerged as a potential alternative for reconstructing extensive glossectomy defects. While previous studies assessing recovery of neurotized ALT flaps in head and neck reconstruction reported superior sensory recovery, improved swallow function, and improved overall patient satisfaction in patients with neurotized flaps vs. non-neurotized ALT flap reconstruction, PAP flap neurotization has not been described and systematically assessed in head and neck patients. MethodsSix patients underwent subtotal tongue reconstruction with neurotized PAP flaps at the authors’ institution from May 2022 until August 2023. A branch of the posterior femoral cutaneous nerve of the PAP flap was coaptated to the lingual nerve. Two-point discrimination, Semmes-Weinstein monofilament, pain, and temperature assessments were conducted at 3, 6, and 12 months postoperatively on the neo-tongue. The MD Anderson speech and deglutition scales and the EORTC-QLQ-H&N35 were used to record functional outcomes and QOL. ResultsMean age was 69±4 years and mean BMI was 25±7kg/m2. Neo-tongue median two-point discrimination at the tip improved from >10mm at 3 months to 6mm at 12 months. All patients had protective pain and temperature perception at the neo-tongue tip at 6-month follow-up. Speech and swallowing function were similar at 12 month follow-up compared with data on neurotized ALT flaps from literature. No neuropathic pain was reported at the donor site at 6-month follow-up. ConclusionsThis is the first case series of PAP flap neurotization in head and neck patients, suggesting potential functional advantages with minimal donor site morbidity. Level of evidenceV Case Series

The Anterior Branch of the Medial Femoral Cutaneous Nerve Innervates Cutaneous and Deep Surgical Incisions in Total Knee Arthroplasty.

Background/Objectives: The intermediate femoral cutaneous nerve (IFCN), the saphenous nerve, and the medial femoral cutaneous nerve (MFCN) innervate the skin of the anteromedial knee region. However, it is unknown whether the MFCN has a deeper innervation. This would be relevant for total knee arthroplasty (TKA) that intersects deeper anteromedial genicular tissue layers. Primary aim: to investigate deeper innervation of the anterior and posterior MFCN branches (MFCN-A and MFCN-P). Secondary aim: to investigate MFCN innervation of the skin covering the anteromedial knee area and medial parapatellar arthrotomy used for TKA. Methods: This study consists of (1) a dissection study and (2) unpublished data and post hoc analysis from a randomized controlled double-blinded volunteer trial (EudraCT number: 2020-004942-12). All volunteers received bilateral active IFCN blocks (nerve block round 1) and saphenous nerve blocks (nerve block round 2). In nerve block round 3, all volunteers were allocated to a selective MFCN-A block. Results: (1) The MFCN-A consistently innervated deeper structures in the anteromedial knee region in all dissected specimens. No deep innervation from the MFCN-P was observed. (2) Sixteen out of nineteen volunteers had an unanesthetized skin gap in the anteromedial knee area and eleven out of the nineteen volunteers had an unanesthetized gap on the skin covering the medial parapatellar arthrotomy before the active MFCN-A block. The anteromedial knee area and medial parapatellar arthrotomy was completely anesthetized after the MFCN-A block in 75% and 82% of cases, respectively. Conclusions: The MFCN-A shows consistent deep innervation in the anteromedial knee region and the area of MFCN-A innervation overlaps the skin area covering the medial parapatellar arthrotomy. Further trials are mandated to investigate whether an MFCN-A block translates into a clinical effect on postoperative pain after total knee arthroplasty or can be used for diagnosis and interventional pain management for chronic neuropathic pain due to damage to the MFCN-A during surgery.