Cutaneous Nerve Research Articles

The Lateral Femoral Cutaneous Nerve is at High Risk During Direct Anterior Approach to the Hip Joint Due to Proximity and Anatomic Variations: A Cadaveric Study

The Lateral Femoral Cutaneous Nerve is at High Risk During Direct Anterior Approach to the Hip Joint Due to Proximity and Anatomic Variations: A Cadaveric Study

High-Risk Retinoblastoma Based on International Classification Systems: Analysis of 1362 Eyes.

To determine the predictive value of international intraocular retinoblastoma classification schemes and the American Joint Committee on Cancer (AJCC) classification for histopathological high-risk features (HRF). Multicentric international collaborative retrospective case series. One thousand three hundred and sixty-two patients with retinoblastoma from 16 centers and 11 countries. Primary enucleation; adjuvant therapy in patients with HRF. High-risk retinoblastoma defined as one or more HRF (anterior segment involvement, massive choroidal invasion, minor choroidal infiltration with prelaminar optic nerve invasion, retrolaminar or resected optic nerve cut end involvement, scleral or microscopic extrascleral infiltration); Metastasis-free survival (MFS) RESULTS: Of the 1362 patients, 751 (55.1%) had HRF. According to the International Classification of Retinoblastoma (ICRB) [Philadelphia vs. Los Angeles (LA)] vs. Children's Oncology Group (COG) classification schemes, the positive predictive value (PPV) of Group D eyes for HRF was 42.0% vs. 35.1% vs. 43.2% respectively and those for group E eyes were 58.5% vs. 59.0% vs. 59.5% respectively. Comparing Group D vs. Group E eyes, there was higher mean number of HRF (SD, range) among Group E eyes using the ICRB Philadelphia [0.7 (0.9, 0.0 - 6.0) vs. 1.3 (1.7, 0.0 - 9.0), p < 0.001], ICRB LA [0.6 (0.8, 0.0 - 6.0) vs. 1.3 (1.7, 0.0 - 9.0), p < 0.001] and COG [0.8 (1.2, 0.0 - 7.0) vs. 1.3 (1.6, 0.0 - 8.0), p < 0.001] classifications. The PPV for HRF was above 55% for AJCC clinical tumor (cT) group cT3a with increments through cT3e to 72.3%. Agreement between ICRB Philadelphia vs ICRB LA, ICRB LA vs COG and ICRB Philadelphia vs COG was 0.9, 0.8 and 0.8 respectively (p < 0.001). Metastasis-free survival rates and overall survival rates were also comparable between all intraocular retinoblastoma classification schemes but better stratified within the AJCC scheme. All intraocular retinoblastoma classification schemes predict HRF and MFS equally. Group E includes a wide spectrum equivalent to AJCC group cT3. Uniform grouping with subcategorization of Group E might improve risk stratification. We propose that everyone across the retinoblastoma world henceforth adopts the AJCC classification for all reporting and publishing.

Pericapsular Nerve Group Block Plus Lateral Femoral Cutaneous Nerve Block vs. Fascia Iliaca Compartment Block in Hip Replacement Surgery

Background: Optimal pain control with limited muscle weakness after total hip arthroplasty (THA) is paramount for a swift initiation of physical therapy and ambulation, thus expediting hospital discharge. FICB (Fascia Iliaca Compartment Block) has been recommended because it offers pain control with a low risk of motor block. PENG (Pericapsular Nerve Group) block with LFCN (Lateral Femoral Cutaneous Nerve) has been proposed as an alternative that offers comparable pain control with a lower risk of motor block; however, evidence is limited. We aimed to investigate the degree of muscle weakness and pain control with PENG + LFCN. Methods: Patients undergoing elective THA from November 2022 to October 2023 have been retrospectively analyzed. The degree of quadriceps femoris muscle paresis was assessed with the MRC scale at 6 h postoperatively. Secondary outcomes: NRS score at 6, 12, and 24 h, total opioid consumption, and time to first rescue opioid. Results: In total, 80 patients were included in the study, 57 received PENG + LFCN, and the remaining 23 received FICB. PENG + LCFN resulted in a higher MRC at 6 h (4 [4; 5] vs. 3 [2; 4] p = 0.0001) and better pain control (mean difference [95% CI] at 6 h, 0.93 [0.14; 1.72], at 12 h, 0.47 [−0.49; 1.43], and at 24 h, 0.39 [0.25; 1.2], p = 0.0006). Less PRN opioids were requested in the PENG + LFCN vs. FICB groups (7.5 [0; 15] MME vs. 60 [40; 80], p = 0.001). Conclusions: PENG + LFCN was associated with less muscle weakness, better pain control, and less rescue opioids in patients undergoing elective THA. A larger prospective study is needed to confirm this finding.

Iatrogenic nerve injury following pelvic ring injury: a network meta-analysis.

Pelvic ring injuries are common in multi-trauma patients and can be life-threatening, necessitating prompt surgical intervention to improve outcomes. However, surgery can lead to complications such as iatrogenic nerve injury. This network meta-analysis aimed to improve outcomes in multi-trauma patients with pelvic ring injuries by evaluating the incidence of iatrogenic nerve injuries, identifying vulnerable nerves, and comparing different fixation methods. A systematic search of MEDLINE, EMBASE, and Scopus from inception to 5 December 2023, revealed 29 comparative studies on the incidence of iatrogenic nerve injury in 1561 adult patients with pelvic ring injuries. Data were extracted on study and patient characteristics, iatrogenic nerve injury incidences, and specific nerve injuries. A random-effects model assessed treatment effects, with subgroup analysis and meta-regression. The main outcomes included odds ratios (ORs) and confidence intervals (CIs) for iatrogenic nerve injuries. Compared with closed reduction internal fixation, robotic-assisted techniques had the highest, and open reduction internal fixation had the lowest ORs for iatrogenic nerve injuries. The robotic-assisted approach ranked best with an OR of 0.22 (95%CI: 0.02-2.16), while closed reduction internal fixation with the anterior approach (OR: 0.71; 95%CI: 0.21-2.48) and open reduction internal fixation with the anterior approach performed the worst. The lateral femoral cutaneous nerve was injured in all open reduction internal fixation with anterior approach procedures and in 66.7% of open reduction internal fixation with posterior approach procedures. Meta-regression showed a significantly lower OR for iatrogenic nerve injuries in patients aged >41.4years in the open reduction internal fixation with anterior approach group (OR: 0.02; 95%CI: 0.001-0.63; p=0.026) compared with younger patients. The robotic-assisted technique may result in the fewest iatrogenic nerve injuries during the treatment of pelvic ring injuries. The posterior approach may also reduce the risk of iatrogenic nerve injuries.

The effect of regional anesthesia of the nerves of the pelvic limb on hemodynamic parameters during operations on the anterior cruciate ligament in dogs

The article presents data on the study of the effect of regional anesthesia of the nerves of the pelvic limb during operations on the anterior cruciate ligament in dogs on hemodynamic parameters: heart rate and average blood pressure. The study was performed throughout the entire surgical intervention. Indicators of the state of circulatory function were recorded before anesthesia, after induction and after 5, 10, 20, 30, 40, 50, 60 minutes after the injection of a local anesthetic, then 10 and 20 minutes after waking up. Depending on the method of anesthesia used, the experimental animals were divided into 4 groups. In the course of the study, it was found that the heart rate in dogs significantly increased, and the average blood pressure decreased when performing surgery on the anterior cruciate ligament under epidural anesthesia and multimodal analgesia in comparison with the group where dogs underwent anesthesia of the lateral cutaneous nerve of the thigh. Such dynamics of indicators can lead to inhibition of circulatory function, which increases the risk and probability of resuscitation during reconstructive knee joint operations.

The Efficacy of Cryoneurolysis on Chronic Pain in Patients with Knee Osteoarthritis; A Double-blinded Randomized Controlled Sham Trial.

The objective was to investigate if cryoneurolysis were superior to sham in reducing pain intensity in patients with chronic knee osteoarthritis. We hypothesized that cryoneurolysis was an effective and safe therapy to reduce chronic pain in patients with knee osteoarthritis. The study was a randomized, double-blind, sham-controlled. Eighty-seven patients with chronic knee osteoarthritis were randomized to either cryoneurolysis or a sham procedure, followed by an exercise program. The target nerves, anterior femoral cutaneous nerve and infrapatellar branch of the saphenous nerve were identified using transcutaneous electrical nerve stimulation and cryoneurolysis was performed ultrasound-guided. The primary outcome was the difference in average pain at 14d post intervention between the cryoneurolysis and sham group. For the intention to treat analysis, no difference was observed for the primary outcome (0.49, 95% CI [-0.3 ; 1.2], p=0.198). Both groups showed a significant reduction in pain scores 14d post intervention (Cryoneurolysis: -1.9, 95% CI [-2.4 ; -1.3], Sham: -1.4, 95% CI [-1.9 ; -0.8]). At 6 months follow-up, a significant reduction in pain was observed in the cryoneurolysis group compared to sham group (1.1, 95% CI [0.3 ; 1.9], p=0.009). Cryoneurolysis was well-tolerated, with minor, transient adverse effects. This study did not show a clinically relevant reduction in pain after intervention comparing cryoneurolysis and sham. Further studies are needed.

Selective Neurectomy with Regenerative Peripheral Nerve Interface Surgery for Facial Synkinesis.

Background: Selective neurectomy (SN) typically leaves cut nerve endings to be either free-floating or buried in facial muscles. Regenerative peripheral nerve interfaces (RPNIs) use autologous skeletal muscle grafts to provide a nonfacial muscle target for reinnervation. Objective: To evaluate the effectiveness of RPNI surgery with SN for improving postoperative facial function through botulinum toxin use and facial movement metrics. Methods: This was a retrospective cohort study comparing patients with synkinesis undergoing SN with and without RPNI surgery. Outcomes included assessing botulinum toxin dosage/frequency and facial movement metrics (margin to reflex distance, brow movement, smile excursion). Statistical tests were applied based on variable distribution. Results: Twenty-four patients were included (12 with RPNI surgery and 12 without; average age, 52.3 and 55.0 years, respectively; p = 0.552). No significant differences were observed in etiology or nerves sacrificed. Patients with RPNI surgery required lower botulinum toxin dosage (72.2 vs. 90.3 units; p = 0.031) and had longer treatment intervals (83.5%, 5.6 months vs. 17.9%, 4.6 months; p = 0.015). No significant differences were observed in facial movement metrics. Conclusion: RPNI surgery with SN may improve facial function as measured by a proxy of reduction in postoperative botulinum toxin dosage and frequency.

Minimum effective concentration 90 (EC90) of ropivacaine for Femoral nerve block: A biased-coin up-and-down sequential method study

Background and Aims: The femoral nerve (FN) is commonly blocked using ropivacaine to provide postoperative analgesia after knee surgery. However, the minimal required concentration has not yet been defined. The aim of this study was to estimate the minimal ropivacaine concentration required to achieve adequate analgesic FN block in 90% of cases (EC90). Methods: This study included 50 patients who were scheduled for knee ligament reconstruction under combined nerve block and general anaesthesia. The FN block was performed using 15 mL of ropivacaine with varying concentrations and considered adequate when associated with pain-free recovery. The sciatic, obturator, and lateral femoral cutaneous nerves were blocked to negate other knee pain generators, and their block success was confirmed. We used the biased-coin design up–down sequential method where the adequacy of an FN block altered the ropivacaine concentration used for the next block. The adequacy of the analgesic block or lack of it was analysed to calculate the analgesic EC90. The quadriceps motor power and morphine requirement were also recorded. Results: The recommended analgesic ropivacaine EC90 was 0.05% w/v. The associated quadriceps weakness and morphine requirement were minimal. Conclusion: FN block using ropivacaine 0.05% w/v may provide adequate analgesia in 90% of patients.

Donor Site Morbidity is Higher When Comparing Bone-Tendon-Bone vs 4-Strand Semitendinosus/Gracilis & All-inside 4-Strand Semitendinosus for Anterior Cruciate Ligament Reconstruction.

To study pain and sensory alterations of 75 (three cohorts of 25 patients) patients that underwent different anterior cruciate ligament reconstruction (ACLR) techniques. The cohorts were divided in the bone-patellar tendon-bone (BTB) autograft, the quadruple strand semitendinosus and gracilis (4ST/G) autograft and the all-inside quadruple strand semitendinosus autograft cohort. We conducted a retrospective study to evaluate pain and sensory alterations after surgery. All these patients followed a similar rehabilitation protocol, being 2 years the minimal follow-up time. Pain was characterized by duration and anatomical location and sensory deficits were evaluated concerning duration and affected area. Patients also scored on 3 different subjective tests: Knee Walking Test (KWT); Lysholm Knee Scoring Scale (LKSS) and International Knee Documentation Committee Subjective Knee Form (IKDC-SKF) and were divided according to its Tegner Activity Level Scale (TALS). The mean anterior knee pain (AKP) duration amongst the 3 cohorts was 1.8 ± 4.5 months and was smaller in the 4ST/G cohort. The majority of patients of the BTB cohort located pain on the patellar tendon while patients in the 4ST/G and all-inside cohorts referred that it was diffuse. At 15 days' post-surgery, hypoesthesia was reported by 56% patients and was higher on the BTB cohort and lower in the all-inside cohort. At 2-year follow-up, the all-inside cohort had no patients with hypoesthesia. In the BTB cohort, the sensitive alterations were only located on the area innervated by the infra-patellar branch of the saphenous nerve (IPBSN). The 4ST/G cohort located the hypoesthesia in the area innervated by the IPBSN and in the area of the lateral sural cutaneous nerve (LSCN). The all-inside group located the sensitive alterations mostly in the LSCN. The KWT was painful in BTB and 4ST/G patients and reported 0% for the all-inside cohort. No statistic significant relevance was found for the IKDC-SKF and LKSS. All cohorts referred pain and sensitive alterations. Using BTB autograft for ACLR seems to condition a higher number of anterior knee pain and hypoesthesia on medium post-operative follow-up and KWT was more often reported. The 4ST/G group had the smallest duration of AKP. The all-inside cohort showed, globally, a lower number of complaints and a shorter time of symptom persistence, namely in terms of sensory deficits. III.

Beyond One-Size-Fits-All: Pioneering a Zone-Based Strategy in Digital Nerve Autografting.

Digital nerve injuries significantly affect hand function and quality of life, necessitating effective reconstruction strategies. Autologous nerve grafting remains the gold standard due to its superior biocompatibility, despite recent advancements in nerve conduits and allogenic grafts. This study aims to propose a novel zone-based strategy for donor nerve selection to improve outcomes in digital nerve reconstruction. A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, searching PubMed, Embase, Cochrane Library, and Web of Science for articles published from January 2004 to December 2023. Inclusion criteria included studies involving adult human subjects undergoing autologous nerve grafting for digital nerve reconstruction, with sensory recovery and donor site morbidity as primary outcome measures. Additionally, an anatomical study comparing donor nerves to digital nerves was included. Five studies met the inclusion criteria: 4 clinical studies and 1 anatomical study. Analysis of the 4 included clinical studies showed that the posterior interosseous nerve had the lowest donor site morbidity (6.25%), while the lateral antebrachial cutaneous nerve (LABCN) demonstrated the best sensory recovery outcomes (mean 2-point discrimination of 5.92 mm, with 100% of patients achieving good to excellent recovery). The sural nerve exhibited acceptable donor site morbidity (15%) but showed the lowest sensory recovery outcomes (mean 2-point discrimination of 10.8 mm, with only 46% of patients reporting good to very good recovery). The anatomical study indicated that the LABCN had the closest match in cross-sectional area and fascicle count to most zones of the digital nerve, supporting its suitability as a graft source. Although there are many nerve reconstruction techniques available, autologous nerve grafting remains the gold standard. Based on the analysis of five studies, this review proposes a new zone-based approach for donor nerve selection, emphasizing matching donor nerves to specific injury zones. This tailored strategy can potentially optimize both functional recovery and donor site morbidity, moving beyond the one-size-fits-all paradigm. The posterior interosseous nerve, LABCN, and SN each provide unique benefits depending on the zone of injury, suggesting that this approach may lead to improved patient outcomes. Future research is needed to validate this framework.

Optimizing Anesthetic Techniques: Special Brachial Plexus and Cutaneous Blocks in Clavicle Fracture Surgeries in Bangladesh

Background: This study compares the efficacy, safety, and resource utilization of brachial plexus + cutaneous nerve blocks (RAG) versus conventional anesthesia (CAG) in patients undergoing clavicle fracture surgeries. Methods: A total of 100 patients were enrolled and equally divided into the RAG (n=50) and CAG (n=50) groups. Baseline characteristics, intraoperative and postoperative outcomes, postoperative complications, length of hospital stay, and resource utilization were evaluated. Pain control was assessed using the Visual Analog Scale (VAS), and patient satisfaction was measured with a satisfaction score. Results: Baseline characteristics were comparable between the groups. Significant differences were observed in postoperative pain control, with the RAG group demonstrating lower VAS scores at all postoperative intervals (p &lt; 0.001). Patient satisfaction was significantly higher in the RAG group (9.5 ± 0.8 vs. 8.3 ± 1.3, p &lt; 0.001). Although no significant differences were found in respiratory depression, nausea, or wound infections, the RAG group showed trends toward reduced nausea and prolonged recovery. The RAG group also had a significantly shorter length of hospital stay (2.8 ± 0.7 days vs. 3.4 ± 1.0 days, p &lt; 0.01) and reduced supplemental analgesic use (20% vs. 50%, p &lt; 0.001). Ultrasonographic guidance was used in 80% of RAG cases. Conclusion: Brachial plexus and cutaneous nerve blocks provide superior postoperative pain control, greater patient satisfaction, and shorter recovery times compared to conventional anesthesia. These advantages, coupled with reduced reliance on supplemental analgesics, make regional anesthesia a more efficient and cost-effective option for clavicle fracture surgeries. Ultrasonographic guidance may further enhance the application of this technique in clinical practice.

Spatial histomorphometry reveals that local peripheral nerves modulate but are not required for skeletal adaptation to applied load in mice

Abstract Mechanical loading is required for bone health and results in skeletal adaptation to optimize strength. Local nerve axons, particularly within the periosteum, may respond to load-induced biomechanical and biochemical cues. However, their role in the bone anabolic response remains controversial. We hypothesized that spatial alignment of periosteal nerves with sites of load-induced bone formation would clarify this relationship. To achieve this, we developed RadialQuant, a custom tool for spatial histomorphometry. Tibiae of control and neurectomized (sciatic/femoral nerve cut) pan-neuronal Baf53b-tdTomato reporter mice were loaded for 5-days. Bone formation and periosteal nerve axon density were then quantified simultaneously in non-decalcified sections of the mid-diaphysis using RadialQuant. In control animals, anabolic loading induced maximal periosteal bone formation at the site of peak compression, as has been reported previously. By contrast, loading did not significantly change overall periosteal nerve density. Neurectomy depleted ~90% of all periosteal axons, with near-total depletion on load-responsive surfaces. Neurectomy alone also caused de novo bone formation on the lateral aspect of the mid-diaphysis. However, neurectomy did not inhibit load-induced increases in periosteal bone area, mineralizing surface, or bone formation rate. Rather, neurectomy spatially redistributed load-induced bone formation towards the lateral tibial surface with a reduction in periosteal bone formation at the posterolateral apex (-63%) and enhancement at the lateral surface (+1360%). Altogether, this contributed to comparable load-induced changes in cortical bone area fraction. Our results show that local skeletal innervation modulates but is not required for skeletal adaptation to applied load in our model. This supports the continued use of loading and weight-bearing exercise as an effective strategy to increase bone mass, even in patients with peripheral nerve damage or dysfunction.

UVB Induces Sympathetic Nervous System Activation and Norepinephrine Secretion to Regulate TheSkin Color of Mice Through the β2-AR/AP-1 Pathway in Epidermal Keratinocytes.

The aim of this study was to investigate how ultraviolet B (UVB) light regulates AP-1 expression via the β2-adrenergic receptor (β2-AR) in epidermal keratinocytes, which in turn regulates melanin synthesis in melanocytes, thereby modulating downstream melanin production in skin hair follicles and altering mouse skin color. We established a UV-irradiated mouse model to investigate the effects of UV radiation on changes in skin color. By measuring changes in the expression of genes related to cutaneous sympathetic nerves, norepinephrine synthesis and melanin synthesis, we investigated the relationship between β2-AR expression and cutaneous melanogenesis and determined the localization of β2-AR in cells. The results of the siRNA-mediated transfection of keratinized cells with downregulated β2-AR expression were further verified in vitro. Our results suggest that UVB alters the color of the dorsal skin in mice by activating the AP-1/IL-6 pathway, which triggers the sympathetic release of norepinephrine, thereby increasing β2-AR expression in keratinocytes. Overall, our study improves the current understanding of how UVB light influences skin color changes and highlights the complex interplay between ultraviolet radiation and skin physiology.

Technical Report on the New Ultrasound Lateral Mid-Shaft Approach to the Sciatic Nerve: A Never-Ending Story.

The anatomy of the sciatic nerve allows it to be blocked at different levels using various anesthetic approaches. However, for several reasons, performing these approaches may be challenging or disadvantageous in specific categories of patients, particularly in obese patients. The objective of this brief technical report is to describe a new technical approach to sciatic nerve block, designed to simplify the procedure for certain categories of patients and less experienced practitioners. Since 2010, more than 5000 procedures have been performed by both experienced anesthesiologists and novice trainees in several hospitals. The ultrasound lateral mid-shaft technique appears to be a safe and effective method for performing a sciatic nerve block, even in obese patients with significant subcutaneous fat and unclear ultrasound images. This approach is particularly beneficial given the various anatomical variations that can occur. By targeting the mid-thigh area, the ultrasound beam accesses anatomical structures that are more superficial, improving the technique's efficacy. Various hospital groups have been performing this technique as a routine procedure, achieving a success rate of nearly 100%. This impressive success rate exceeds that of other conventional techniques documented in the literature. Additionally, there have been significant improvements in comfort and ease for anesthetists. This method allows the anesthetic to spread around the paraneural sheath, covering the posterior femoral cutaneous nerve. Finally, it is performed in the supine position without the need to mobilize the lower limbs, ensuring patient comfort, especially in cases of fractures or lower limb injuries. Further studies are needed to confirm these results.

Keratinocyte-derived extracellular vesicles in painful diabetic neuropathy.

Painful diabetic neuropathy (PDN) is a challenging complication of diabetes with patients experiencing a painful and burning sensation in their extremities. Existing treatments provide limited relief without addressing the underlying mechanisms of the disease. PDN involves the gradual degeneration of nerve fibers in the skin. Keratinocytes, the most abundant epidermal cell type, are closely positioned to cutaneous nerve terminals, suggesting the possibility of bi-directional communication. Extracellular vesicles are lipid-bilayer encapsulated nanovesicles released from many cell types that mediate cell to cell communication. The role of keratinocyte-derived extracellular vesicles (KDEVs) in influencing signaling between the skin and cutaneous nerve terminals and their contribution to the genesis of PDN has not been explored. In this study, we characterized KDEVs in a well-established high-fat diet mouse model of PDN using primary adult mouse keratinocyte cultures. We obtained highly enriched KDEVs through size-exclusion chromatography and then analyzed their molecular cargo using proteomic analysis and small RNA sequencing. We found significant differences in the protein and microRNA content of high-fat diet KDEVs compared to KDEVs obtained from control mice on a regular diet, including pathways involved in axon guidance and synaptic transmission. Additionally, using an in vivo conditional extracellular vesicle reporter mouse model, we demonstrated that epidermal-originating GFP-tagged KDEVs are retrogradely trafficked into the dorsal root ganglion (DRG) neuron cell bodies. This study presents the first comprehensive isolation and molecular characterization of the KDEV protein and microRNA cargo in RD and HFD mice. Our findings suggest a potential novel communication pathway between keratinocytes and DRG neurons in the skin, which could have implications for PDN.

The Melanocyte and Nerve Fiber Cross-Talk, Facilitated Also by Semaphorin-4A, Enhances UV-B-Induced Melanogenesis.

Epidermal melanocytes form synaptic-like contacts with cutaneous nerve fibers, but the functional outcome of these connections remains elusive. In this pilot study we used our fully humanized re-innervated skin organ culture model to investigate melanocyte-nerve fiber interactions in UV-B-induced melanogenesis. UV-B-irradiation significantly enhanced melanin content and tyrosinase activity in re-innervated skin compared to non-innervated controls, indicating that neuronal presence is essential for exacerbating pigmentation upon UV-B irradiation in long-term culture. Comparative transcriptomic analysis between laser-capture-microdissected melanocytes from freshly embedded human skin and published microarray data on invitro primary melanocytes identified Semaphorin-4A (SEMA4A) as possible mediator of melanocyte-nerve fibers interactions. SEMA4A protein levels in Gp100+-epidermal melanocytes were significantly higher in re-innervated skin, and reduced by UV-B treatment. Analysis of melanocytes invitro showed reduced SEMA4A protein expression 24 h after UV-B-irradiation while SEMA4A secretion into the medium was increased. Beta-tubulin expression and axon growth in sensory neurons were stimulated by conditioned media (CM) from UV-B irradiated melanocytes. When this neuronal-conditioned medium was transferred to fresh melanocytes, melanin content increased, but only if neurons had been treated with CM from UV-B irradiated melanocytes. These findings highlight the importance of melanocyte-neuron interactions for UV-B-induced melanogenesis and suggest that secreted proteins (e.g., SEMA4A) can function as a novel target to treat hypo- and hyperpigmentation disorders.

Robotic-Assisted Microsurgery in Gender-Affirming Phalloplasty.

Genital gender-affirming masculinization surgeries require handling of small vessels and nerves handling in deep planes. Since the introduction of the Symani Surgical System for robotic-assisted microsurgery in clinical practice, its value in handling small and deep vessels via additional distal motion axes, motion scaling, and tremor elimination has been demonstrated. We combined the Symani with the robotic exoscope RoboticScope to achieve maximum flexibility and ergonomics for the microsurgeon. Here, we present the initial application of robotic-assisted microsurgery for gender-affirming phalloplasty. The Symani and the RoboticScope were used to perform the end-to-side nerve coaptation of the lateral antebrachial cutaneous nerve to the dorsal nerve of the clitoris with five epineural 9.0 Ethilon sutures. Arterial anastomosis to the deep inferior epigastric artery (DIEA) was completed in an end-to-end fashion with six 8.0 Ethilon sutures. Cephalic vein anastomosis to the great saphenous vein was performed manually in an end-to-end fashion using a 3.5-mm coupler. The time for nerve coaptation was 17 minutes; for arterial anastomosis, 26 minutes; and for vein anastomosis, 6 minutes. Time for flap ischemia was 157 minutes. Incision to closure was performed in 401 minutes. Symani's tremor elimination and motion scaling support precise arterial anastomosis and nerve coaptation. The additional degrees of freedom distal to the tips of the instruments enable flexible operation in deep planes, such as the periclitoral space. Combining Symani with a robotic exoscope enables a comfortable remote positioning for the surgeon. The presented case demonstrates feasibility and encourages further exploration to elucidate the potential benefits of this robotic-assisted technique.

An approach to the prevention and treatment of neuropathic pain at the radial forearm phalloplasty donor site

This article presents a comprehensive strategy for both the prevention and treatment of neuropathic pain at the radial forearm (RF) donor site. This strategy is presented within the framework of RF phalloplasty, based on the senior author’s practice and the premise that of all RF reconstructions, phalloplasty holds the greatest potential for postoperative neuropathic pain due to flap size and the inherent division of multiple antebrachial cutaneous nerves to provide for flap sensation. This proposed protocol offers a thorough care pathway that integrates techniques in peripheral nerve surgery with perioperative clinical strategies to prevent and treat neuropathic pain. Specific technical recommendations for the prevention and treatment of postoperative neuromas, compression neuropathies, and hyperalgesia of each peripheral nerve involved in RF phalloplasty flap harvest are proposed. These strategies can be adapted and applied to RF flaps utilized in other reconstructive areas.

The Diagnosis and Management of Meralgia Paresthetica: A Narrative Review.

Meralgia paresthetica (MP) is a sensory mononeuropathy affecting the lateral femoral cutaneous nerve. Diagnosis is typically made clinically, often utilising multiple diagnostic aids such as imaging and electrophysiology. Upon diagnosis, the management of MP follows the standard ladder, with conservative management first line, followed by steroid injection and finally surgery. Surgery may be neurolysis or neurectomy. A literature review of the PubMed database was performed identifying 594 papers regarding MP or the lateral femoral cutaneous nerve. Following a two-stage screening process and reference searching, 34 articles were included in this review, 11 discussing diagnosis and 23 discussing management. Despite the longstanding knowledge of MP, there remains limited comprehensive research discussing its diagnosis and management. Diagnosis of MP is based on clinical examination, imaging and electrophysiology. There is no obviously superior diagnostic strategy for MP. Once that diagnosis is made, the management strategy is typical of any condition, wherein a patient will move up the intervention ladder. It is apparent that conservative management and steroid injection are both adequate in most patients. Where these strategies fail, surgical options such as decompression, radiofrequency ablation or neurectomy are suitable for the majority of remaining patients. While both neurolysis and neurectomy are described as appropriate strategies, there is a scope for discussion regarding whether one is superior. Other management strategies such as botox, acupuncture and kinesio taping may have some value, but limited research exists on these strategies and further research into these is required.

Anatomical study of the innervation of the posterior elbow joint capsule: implications for ultrasound-guided peripheral nerve block and radiofrequency ablation procedures

IntroductionUltrasound-guided peripheral nerve block and radiofrequency ablation have been developed for pain management in various joints including the hip, knee and shoulder, but not the elbow. Precise three-dimensional (3D) localization...