The majority of nerve reconstruction techniques are performed on the sciatic nerve in above-the-knee amputees. However, sensory branches in the anterior thigh are often overlooked and may contribute to postoperative pain. This study aims to provide an anatomical guide for performing targeted muscle reinnervation (TMR) in the anterior thigh to improve pain in transfemoral amputees. This observational study was conducted on 12 formalin-fixed, well-embalmed cadaveric lower limbs. The femoral nerve was identified and dissected to isolate its anterior and posterior divisions. The saphenous nerve is the terminal branch of the posterior division of the femoral nerve, entering the adductor canal. Linear measurements were taken from the midpoint of the inguinal ligament (IL) in the direction of the medial femoral condyle. An additional proof-of-concept dissection on 2 cadaveric limbs was completed using the recorded measurements to identify the saphenous nerve and nearby motor branches. The median distance from the IL to the saphenous branch point was 19 cm (IQR, 19.1-25.5 cm). The nerve to vastus medialis (VM) was the closest motor branch to the saphenous nerve in 83% of limbs, originating at a median distance of 17.8 cm (IQR, 15.9-21.5 cm). From the posterior division of the femoral nerves, 60% gave 2 motor branches to VM, 30% gave 3, and 10% gave 4. In 2 limbs, we observed no VM branches from the posterior division and found that the closest motor branches were to vastus intermedius (9 cm) and to the sartorius (18 cm). Proximally, branches to vastus intermedius, rectus femoris, and sartorius were highly variable. Using measurements from the 12 cadavers, the saphenous nerve and VM motor branches were found in both cadaveric limbs 16-26 cm from the inguinal crease. Surgeons performing TMR of the saphenous nerve should explore the anterior medial thigh approximately 16-26 cm distal to the inguinal crease to reliably identify VM targets. If more proximal, motor targets are more variable, and other nerve reconstruction techniques such as regenerative peripheral nerve interfaces should be utilized.

Systematic Review and Meta-Analysis Comparing the Efficacy of CHIVA and Conventional Stripping and Ablation Techniques.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and disabling complication of several chemotherapeutic agents. Peripheral nerve stimulation (PNS) has emerged as a potential neuromodulatory treatment, but its effectiveness in CIPN remains unclear. This study evaluates whether optimizing PNS lead placement improves clinical outcomes. Four adults with moderate to severe CIPN (Numerical Rating Scale [NRS] ≥ 4) underwent PNS implantation. Lead placements were categorized as proximal (L5/S1), intermediate (femoral or sciatic at the subgluteal region), or distal (saphenous or popliteal nerves at the midthigh). Pain was assessed using the NRS, and neuropathy symptoms using the Treatment-Induced Neuropathy Assessment Scale (TNAS) at baseline and at 1, 2, and 3 months. Distal lead placement resulted in the greatest improvement, with 30-40% pain reduction and measurable decrease in TNAS scores. Proximal and intermediate placements demonstrated relatively minimal benefit. Two patients with distal placement also reduced their opioid use. No major adverse events occurred. Preliminary findings suggest that PNS lead placement closer to the symptomatic region may improve CIPN-related pain and neuropathic symptoms. These results validate the importance of optimizing lead positioning and support further prospective evaluation.

Is there a need to modify the anatomical targets for genicular nerve ablation in prosthetic knees compared with native knees? A cadaveric study.

Background:Hamstring tendon autografts are the most commonly used grafts for anterior cruciate ligament (ACL) reconstruction and are usually harvested through an anterior approach. This harvest is not without risks of complications, and the tendons can alternatively be harvested through a posterior approach.Indications:Patients undergoing autograft hamstring ACL reconstruction without previous ipsilateral hamstring harvest or distal hamstring injury.Technique Description:The patient is positioned supine, and the leg is elevated. With the knee in flexion, the semitendinosus can be palpated as the most lateral superficial of the medial hamstring tendons. A small incision is then made over the semitendinosus 1 cm proximal to the flexion crease, and the fascia is opened. An open hamstring stripper is then used to harvest the graft proximally with the leg in extension. The graft is then passed through a closed tendon stripper, and the remaining tendon is stripped distally. The graft is then quadrupled on the back table with the sutures on the inside of the graft, and the graft is soaked in a tobramycin-infused saline solution.Results:Compared to anterior hamstring harvest, posterior harvest is associated with a decreased incidence of (infrapatellar branch) saphenous nerve damage (0.4% vs 10.2%), lower risk of premature graft harvest (0% vs 2-9%), shorter operative time (4 to 13 minutes shorter), and higher cosmetic satisfaction (92% vs 80%).Discussion/Conclusion:Posterior hamstring harvest is a safe and reliable technique that is associated with a lower risk of complications compared to anterior hamstring harvest and should be considered for hamstring autograft ACL reconstruction.Patient Consent Disclosure Statement:The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Background and Aims:Adductor canal block (ACB) has emerged as a selective sensory technique to provide pain relief to the anterior aspect of the knee joint. Despite a large amount of available literature, the ideal site for performing ACB remains debatable. With the use of ultrasound, it is now possible to define the exact location of the adductor canal (AC). The objectives of our cadaveric study were to examine the nerves captured by methylene blue dye (MBD) and the stain pattern of the nerves within the AC following mid-AC injection.Methods:We scanned the thigh area of six lightly embalmed cadavers (12 specimens) and marked the midpoint of the AC using ultrasound and injected 10 mL of (MBD) at this level. Thirty minutes later, all the specimens were dissected to document the frequency and stain pattern of various nerves traversing through the AC.Results:The vastoadductor membrane and saphenous nerve got stained heavily (+3) in all twelve specimens, while the nerve to vastus medialis stained heavily (+3) in four and moderately (+2) in eight specimens. Both the medial cutaneous nerve of the thigh and the intermediate cutaneous nerve of the thigh were stained moderately (+2) in four and two specimens, respectively. There was no spread of the dye into the distal femoral triangle area.Conclusions:Injection of MBD in the sonographically located mid part of the AC consistently involved the saphenous nerve and nerve to vastus medialis, and hence may be the optimal site for performing ACB.

Cadaveric evaluation of distal tibial autograft harvest: Can we optimize bone harvesting?

Effect of Nalbuphine on Combined Ultrasound Guided Sciatic and Saphenous Nerve Block in Orthopedic Leg Surgery

Five years after the onset of the SARS-CoV-2 pandemic, post-COVID-19 condition continues to affect millions of subjects with persistent symptoms that significantly impair quality of life. Post-COVID-19 pain, particularly in women, has emerged as a frequent yet underestimated symptom. The validation and identification of animal models that reproduce persistent symptoms after an acute SARS-CoV-2 infection is crucial for a better understanding of the underlying mechanisms. The aim of the current study was to evaluate thermal nociception, biomarkers of inflammation, and nerve tissue damage in a female animal model of post-COVID-19 condition. A SARS-CoV-2 infection model was established by intranasal administration of the Omicron variant (BA.1.17 lineage) in transgenic female C57BL/6 mice expressing the human ACE2 receptor (hACE2). Nociception was assessed using the hot-plate test for 28 days post-infection. Afterwards, animals were sacrificed to analyze plasma inflammatory biomarkers by multiplex analysis. In addition, IL-6, IL-18, and IL-1β expression were evaluated by immunohistochemistry to analyze neural inflammation in the saphenous nerve. The results revealed that heat nociceptive thresholds in infected mice did not significantly differ from those of non-infected, but a trend toward lower thresholds was observed in the infected group (days 14 and 28 post-infection). In addition, a slight modification in pro- and anti-inflammatory cytokines/chemokines in plasma was detected, but no changes in the expression of IL-6, IL-1β, or IL-18 were observed in the saphenous nerve. Based on all the analyses conducted, infection with the Omicron variant of SARS-CoV-2 did not induce thermal sensitization in animals nor alterations in the expression of inflammatory biomarkers in the saphenous nerve. Finally, a slight state of systemic inflammation was present in the infected animals. The absence of detectable changes in this animal model underscores the need for further research to clarify the discrepancies observed in human patients and to explore alternative pathways potentially involved in post-COVID-19 pain syndromes.

The accurate identification of peripheral nerves using ultrasound is essential for the safe and effective application of image-guided interventions in pain management. The femoral nerve (FN) and saphenous nerve (SN) are common targets for peripheral nerve invasive techniques, yet their depth and anatomical variability can impact procedural success. The objective was to describe the ultrasound anatomy of the FN and SN in healthy individuals and analyze how anthropometric variables predict its location. Design: A cross-sectional study was conducted in 30 healthy participants. Ultrasound measurements included subcutaneous tissue thickness, nerve depth, and cross-sectional area of the FN and SN. Anthropometric data such as BMI, limb length, and circumference measurements were also recorded. Pearson correlations and hierarchical regression models were used to identify predictors of nerve location. Results: No significant side-to-side differences were found for any variable (p > 0.05). Subcutaneous tissue thickness and limb circumference showed strong correlations with nerve depth. The final hierarchical regression model explained 67.0% of the variance in skin-to-FN distance and 82.3% for skin-to-SN distance. Subcutaneous tissue at the inguinal region and mid-thigh, as well as lower limb length and mid-thigh circumference, were significant predictors for FN depth. For the SN, subcutaneous thickness at mid-thigh, mid-thigh circumference, and inguinal subcutaneous tissue were the most relevant predictors. Conclusion: Anthropometric variables, especially subcutaneous tissue thickness and limb circumferences, are reliable predictors of FN and SN depth in healthy subjects. These findings support the use of simple anatomical measures to improve planning and safety in ultrasound-guided procedures.

Directed functional reinnervation to curb nociception and enable sensation

Background and Objectives: Despite the high rate of donor site morbidity, a bone–patellar tendon–bone (BPTB) graft remains the gold standard when choosing a graft for anterior cruciate ligament (ACL) reconstruction. Damage to the infrapatellar branch of the saphenous nerve (IPBSN) during graft harvesting results in sensory deficits. Despite its high occurrence in the postoperative period, many patients go untreated, leading to a lower quality of life and potential professional impairment. The aim of this study was to assess the effectiveness of PRF therapy in alleviating sensory deficits and enhancing sensory nerve function in patients who have undergone BTB ACL reconstruction. Materials and Methods: This study was registered at ClinicalTrials.gov (Name of registry: ClinicalTrials.gov; Trial registration number: NCT07257666; Date of registration: 2 December 2025; Study start date: 7 January 2022). Over a one-year period, the pilot study enrolled 53 patients, treated them with BPTB ACL reconstruction, and divided them into two groups. The testing group’s donor site and subcutaneous tissue were treated with Vivostat® PRF, whereas the standard group’s donor site and subcutaneous tissue remained untreated. The primary outcome measured was a reduction in the subjective numbness, which was tested during follow-up checks. Secondary outcomes included the evaluation of subjective knee scores for functional recovery, reported by the patients on control exams. Results: The use of Vivostat® PRF resulted in a statistically significant reduction in sensory deficit among the groups at eight months (p < 0.05) and twelve months (p < 0.01) following surgery, favoring the testing group. The most substantial decrease in symptomatic patients was observed between four and eight months post-surgery, with no statistically significant difference found between the eight- and twelve-month follow-ups (p > 0.05). Evaluations of subjective knee function and activity scores showed no statistically significant differences between the groups. Conclusions: Using Vivostat® PRF helps reduce sensory impairment in the area and minimizes donor site morbidity after BPTB ACL reconstruction.

Assuming the voltage-gated sodium channel (VGSC) NaV1.7 facilitates action potential generation upon slow electrical depolarization, we investigated protoxin II and TTX to target VGSC sub-types and to assess their role in C-fiber excitability when stimulated with sinusoidal single 1 Hz pulse (500 ms) and repetitive 4 Hz stimuli. We performed ex vivo extracellular compound potentials (CAP) recordings of pig saphenous nerve and in vivo pig single nerve fiber (SNF) recordings of heat- mechanosensitive (“polymodal”) nociceptors (C-HT) and low- threshold mechanoresponsive C-fibers (C-LTMR) upon electrical 1 and 4 Hz sinusoidal stimulation, which evoke a discharge burst and a tonic response, respectively. Both toxins reduced C-CAP amplitudes and conduction velocity. Number of action potentials evoked by low-intensity phasic (1 Hz) or tonic (4 Hz) sinusoidal stimulation were reduced in C-HT nociceptors after protoxin. In C-LTMR fibers, protoxin reduced the number of action potentials to 4 Hz, but did not affect 1 Hz discharges. The toxins did not increase the delay of action potential initiation of C-CAPs or during SNF. Our results confirm the functional role of NaV1.7 to tonic supra-threshold electrical 4 Hz sinusoidal action potential firing in C-fibers. Protoxin reduced AP discharges to low-intensity phasic 1 Hz stimuli in C-HT nociceptors but not C-LTMR touch fibers. This finding suggests a differential functional role of NaV1.7 between C-fiber classes. Peripheral NaV1.7 blockade seems to increase the depolarization level required for C-nociceptor activation, and this might be relevant to target clinically ongoing pain.

IntroductionLocoregional anesthesia using local anesthetics has been proposed as a highly selective method for perioperative acute pain management because it helps prevent the onset of noxious stimuli. However, a limitation of this technique is the possibility of nerve block failure. Infrared thermography (IRT) has been suggested as a non-invasive tool to assess the success of peripheral nerve blocks by detecting temperature changes related to vasodilation. This study aimed to evaluate the effect of peripheral nerve blocks on the superficial thermal response of limbs in dogs undergoing trauma or orthopedic surgery.MethodsA total of 26 dogs of various breeds, classified as ASA 1 or 2 and undergoing thoracic or pelvic limb, or abdominal surgery, were divided into two groups based on the analgesic technique used. In the experimental group [peripheral nerve block (PNB) n = 20], composed of animals undergoing trauma or orthopedic surgery, bupivacaine was infiltrated into the brachial plexus or the saphenous and sciatic nerves. The control group (n = 6) underwent general anesthesia and surgery, and they received conventional injectable analgesia. The variables assessed included maximum (Tmax), mean (Tmean), and minimum (Tmin.) temperatures of the axillary region, groin, and lateral femoral area, as well as rectal temperature (T°C). Measurements were taken at baseline (TBasal), and 5 (T5min.), 10 (T10min.), and 15 min (T15min.) after treatment.ResultsTmax, Tmean, and Tmin were significantly higher in the PNB group (by 2–3 °C) compared to the control group (p = 0.01). In the PNB group, superficial temperatures decreased by approximately 1 °C from baseline (p = 0.001), whereas the control group exhibited a greater decrease of approximately 3 °C at the same time points (p = 0.001). Rectal temperature was 2 °C higher in the PNB group compared to the control group (p = 0.01), although only the control group showed a progressive decrease over time (p = 0.05). No significant correlation was found between surface and rectal temperatures.DiscussionPeripheral nerve blocks with bupivacaine induced localized vasodilation, resulting in increased superficial heat radiation. This thermal response may serve as an indirect indicator complementary of nerve block effectiveness, supporting the use of IRT as a clinical tool to evaluate peripheral nerve block success in dogs. Further studies are recommended to confirm and validate its clinical application.

Ultrasound-Guided Percutaneous Electrocoagulation of Pathological Perforating Veins in the Treatment of Advanced Chronic Venous Insufficiency of the Lower Extremities: A Retrospective Cohort Study.

Optimizing electrode placement for saphenous nerve conduction study based on cadaveric dissection and probabilistic mapping

Chronic non-healing ulcers (CNUs), particularly those complicated by neuropathy and multi-morbidity, represent a profound therapeutic challenge with limited effective interventions. This case study investigates the novel application of topical anhydrous aluminum potassium sulfate (AAPS), a traditional astringent agent, for a refractory postsurgical ulcer with concomitant saphenous neuropathy. A 65-year-old male with poorly-controlled type 2 diabetes mellitus, schizophrenia, and severe alcohol use disorder, presented with a three-year-old, post-surgical CNU inferior to the right medial malleolus. The ulcer had failed multiple courses of targeted intravenous and oral antibiotics and was not amenable to a planned skin graft due to psychosocial constraints. Clinical and neurophysiological examination confirmed severe sensory mononeuropathy of the right saphenous nerve with Utah Early Neuropathy Scale (UENS) score of 9/12. After exhaustive conventional therapy failed, a protocol of once-daily topical AAPS dusting powder was initiated alongside phased mechanical debridement. The intervention resulted in complete ulcer closure within 60 days, with a 57% reduction in surface area observed by day 30. Critically, the patient reported the return of protective sensation (pain) at day 30, and the UENS score improved significantly to 3/12 post-treatment, indicating neurological recovery. No recurrence was noted during a six-month surveillance period. This first-reported case demonstrates AAPS dusting as a highly effective intervention for complex CNUs, achieving both tissue repair and neurological recovery. The clinical outcomes align with recent evidence of AAPS-mediated ERK pathway inhibition, suggesting a potential molecular mechanism for its therapeutic action in chronic wounds. These dramatic results warrant controlled trials to validate efficacy and the mechanistic pathways. anhydrous aluminum potassium sulfate, chronic non-healing ulcer, ERK pathway, nerve regeneration, wound healing.

Anatomical variations in nerves are common and can significantly impact ultrasound-guided regional anesthesia. They directly influence needle trajectory, local anesthetic spread, and block efficacy, contributing to procedural failure or complications. However, the literature specifically addressing the clinical implications of neural variations for regional anesthesia remains limited. This narrative review synthesizes evidence on three key aspects: (1) variations of common peripheral nerves and their clinical significance in regional anesthesia (including the terminal branches of the trigeminal nerve, suprascapular nerve, phrenic nerve, lumbar plexus, saphenous nerve, obturator nerve, and sciatic nerve); (2) variations of major vessels relevant to regional anesthesia and their clinical significance in regional anesthesia (including the Adamkiewicz artery and vertebral artery); (3) variations of the spine and spinal nerve roots and their clinical significance in regional anesthesia. This review systematically synthesizes current evidence on these anatomical variations and introduces practical resources, including regional ultrasound guidance and tables correlating specific variants with technical modifications, to enhance ultrasound recognition and clinical decision-making, thereby serving as a valuable reference for clinicians.

Objective: Knee osteoarthritis (OA) is a prevalent cause of chronic pain and functional impairment. Ultrasound-guided saphenous nerve block has emerged as a promising non-surgical treatment modality. This study evaluates the comparative efficacy of bupivacaine alone versus bupivacaine with triamcinolone acetonide in ultrasound-guided saphenous nerve block for OA knee pain. Methods: A prospective, randomized, double-blind study was conducted involving 80 patients aged 30–80 y with chronic OA knee pain (Grade II or III). Patients were allocated to two groups: Group T received 4 ml of 0.5% bupivacaine+40 mg triamcinolone acetonide; Group B received 4 ml of 0.5% bupivacaine alone. Both solutions were diluted to 10 ml with normal saline. Pain intensity (VAS), functional disability (WOMAC index), and patient satisfaction were assessed at baseline, 1 h, 1 w, 2 w, 1 mo, 3 mo, and 6 mo post-block. Results: Both groups showed significant reductions in VAS and WOMAC scores over time (p&lt;0.05). However, Group T showed superior pain relief and functional improvement at all follow-up points (p&lt;0.05). Grade II OA patients in both groups had better outcomes compared to Grade III. No significant procedural complications were noted. Conclusion: Ultrasound-guided saphenous nerve block using bupivacaine with triamcinolone acetonide provides prolonged and superior analgesia and functional improvement compared to bupivacaine alone in patients with OA knee. This technique is safe, effective, and minimally invasive, warranting consideration in non-surgical OA knee management.

Dynamic ultrasound examination for postoperative intermittent irritation of the infrapatellar branch of the saphenous nerve