Peripheral Nerve Stimulation for Treating Acute Pain Following Traumatic Fracture: A Case Report of Rapid-Onset Analgesia Without Motor Blockade.

Analgesia following acute traumatic fracture remains a clinical challenge. Pain relief via peripheral nerve stimulation (PNS) is a promising treatment modality due to its opioid-sparing effects and rapid, reversible sensory blockade without motor blockade. We present the case of a patient who suffered a traumatic tibial plateau fracture. A popliteal sciatic PNS device was placed on postoperative day 1 following inadequate pain control. The patient reported marked pain relief, a significant reduction in morphine milligram equivalent (MME) utilization, and improved early functional recovery. The PNS lead was removed at the patient's 2-month follow-up visit without any adverse events.

Localization of the greater occipital nerve through palpation of bony landmarks: A cadaveric study.

OBJECTIVE: to provide anatomic confirmation that standard methods which practitioners skilled in palpation use, can reliably identify the most likely site of emergence of the greater occipital nerve in most patients. The location and frequency of subcutaneous emergence of the greater occipital nerve and occipital artery with respect to the external occipital protuberance-mastoid line are reported. METHODS: The external occipital protuberance and the mastoid processes were identified by palpation bilaterally on 57 body donors and the medial trisection point of a line connecting these bony landmarks was identified. A 4 cm circular dissection guide divided into 4 quadrants was centered on the trisection point and used to guide the removal of a circle of skin. The in-situ location of the nerve and artery were exposed by deep dissection within the circle. The frequency of the emergence and occurrence of the nerve and artery by quadrant were analyzed. RESULTS: In 114 total dissections the greater occipital nerve was found to emerge within the circle 96 times (84%) and the occipital artery 100 times (88%). The nerve (90%) and artery (81%) emerged from the two inferior quadrants most of the time with no difference noted between male and female donors. The greater occipital nerve and occipital artery were found to emerge together most commonly in inferior lateral quadrant. Branches of the nerve and artery traveled together most frequently through the two lateral quadrants. CONCLUSION: This study confirmed that the medial trisection point of the external occipital protuberance-mastoid line can be located via palpation and reliably used to pinpoint the subcutaneous emergence of the greater occipital nerve and occipital artery in most individuals. When relying on palpation alone to identify the trisection point in the clinic, infusion of nerve block inferior and lateral to this point is most likely to bathe the greater occipital nerve in anesthetic.

Galacturonic acid-capsaicin prodrug for prolonged nociceptive-selective nerve blockade.

There is an urgent clinical need to develop nerve-blocking agents capable of inducing long duration sensory block without muscle weakness or paralysis to treat post-operative and chronic pain conditions. Here, we report a galacturonic acid-capsaicin (GalA-CAP) prodrug as an effective nociceptive-selective axon blocking agent. Capsaicin selectively acts on nociceptive signaling without motor nerve blockade or disruption of proprioception and touch sensation, and the galacturonic acid moiety enhance prodrug permeability across the restrictive peripheral nerve barriers (PNBs) via carrier-mediated transport by the facilitative glucose transporters (GLUTs). In addition, following prodrug transport across PNBs, the inactive prodrug is converted to active capsaicin through linker hydrolysis, leading to sustained drug release. A single injection of GalA-CAP prodrug at the sciatic nerves of rats led to nociceptive-selective nerve blockade lasting for 234 ± 37 h, which is a sufficient duration to address the most intense period of postsurgical pain. Furthermore, the prodrug markedly mitigated capsaicin-associated side effects, leading to a notable decrease in systemic toxicity, benign local tissue reactions, and diminished burning and irritant effects.

The effect of anesthetic blockade of greater occipital nerve during the withdrawal period of the medication overuse headache treatment.

Background and purpose:

Discontinua­tion of medication still remains a key element in the treatment of medication overuse headache (MOH), but there is no consensus on the withdrawal procedure. We aimed to share the promising results of anesthetic blockade of greater occipital nerve (GON), which can be an alternative to existing treatments during the early withdrawal period of MOH treatment.

This study was conducted using regular electronic medical records and headache diaries of patients diagnosed with MOH and treated with anesthetic GON blockade with 0.5% bupivacaine solution in a specia­lized headache outpatient clinic. A total of 86 patients who developed MOH while being followed up for chronic migraine were included in the study.

The treatment schemes for MOH are based on expert consensus and withdrawal strategies are the most challenging part of treatment. In our study, numerical rating scale for headache intensity, overused medication consumption per month, headache frequency (day/month) and the duration of each attack (hour/day) decreased significantly in the first month compared to pre-treatment (p < 0.01). 

Conclusion – Our study suggests that GON blockade can be used as a good alternative therapy in the treatment of MOH.

The effectiveness of ambulatory continuous popliteal sciatic nerve blockade on patient-reported overall benefit of analgesia in patients undergoing foot or ankle surgery (CAREFREE trial); a randomized, open label, non-inferiority trial.

STUDY OBJECTIVE: Management of pain after foot and ankle surgery remains a concern for patients and healthcare professionals. This study determined the effectiveness of ambulatory continuous popliteal sciatic nerve blockade, compared to standard of care, on overall benefit of analgesia score (OBAS) in patients undergoing foot or ankle surgery. We hypothesized that usage of ambulatory continuous popliteal sciatic nerve blockade is non-inferior to standard of care. DESIGN: Single center, randomized, non-inferiority trial. SETTING: Tertiary hospital in the Netherlands. PATIENTS: Patients were enrolled if ≥18 years and scheduled for elective inpatient foot or ankle surgery. INTERVENTION: Patients were randomized to ambulatory continuous popliteal sciatic nerve blockade or standard of care. MEASUREMENTS: The primary outcome was the difference in OBAS, which includes pain, side effects of analgesics, and patient satisfaction, measured daily from the first to the third day after surgery. A non-inferiority margin of 2 was set as the upper limit for the 90% confidence interval of the difference in OBAS score. Mixed-effects modeling was employed to analyze differences in OBAS scores over time. Secondary outcome was the difference in opioid consumption. MAIN RESULTS: Patients were randomized to standard of care (n = 22), or ambulatory continuous popliteal sciatic nerve blockade (n = 22). Analyzing the first three postoperative days, the OBAS was significantly lower over time in the ambulatory continuous popliteal sciatic nerve blockade group compared to standard of care, demonstrating non-inferiority (-1.9 points, 90% CI -3.1 to -0.7). During the first five postoperative days, patients with ambulatory continuous popliteal sciatic nerve blockade consumed significantly fewer opioids over time compared to standard of care (-8.7 oral morphine milligram equivalents; 95% CI -16.1 to -1.4). CONCLUSIONS: Ambulatory continuous popliteal sciatic nerve blockade is non-inferior to standard of care with single shot popliteal sciatic nerve blockade on patient-reported overall benefit of analgesia.

Regional Anesthesia for Arthroscopic Knee Repair in a Patient With Hypertrophic Obstructive Cardiomyopathy (HOCM) Under Monitored Anesthesia Care With Dexmedetomidine Infusion.

Patients with hypertrophic obstructive cardiomyopathy (HOCM) who are scheduled for elective, noncardiac surgery present a distinctive challenge for perioperative healthcare providers. The use of general anesthesia and neuraxial anesthesia carries the risk of unpredictable hemodynamic changes and potential complications. Regional anesthesia (RA) emerges as a prudent and effective option for HOCM patients. RA provides advantages such as minimizing hemodynamic fluctuations, avoiding intubation, reducing pharmacologic side effects, facilitating enhanced recovery after surgery, and contributing to greater patient satisfaction. We share the case of a 15-year-old individual diagnosed with HOCM and exercise intolerance, undergoing arthroscopic repair for right patellar instability. In this instance, the patient received preoperative peripheral nerve blocks for surgical anesthesia and underwent repair utilizing monitored anesthesia care (MAC) with a dexmedetomidine (DEX) infusion.

Design and implementation of a training programme on ultrasound-guided lower limb peripheral nerve blockade: An Advanced Clinical Practitioner's personal journey.

Increased demand in services, workforce pressures and continued financial constraints has resulted in a significant expansion in advanced clinical practice roles in the United Kingdom. This article will describe the personal experience of a perioperative Advanced Clinical Practitioner in the design and implementation of a training programme to achieve competence in ultrasound-guided lower limb peripheral nerve blockade. Three specific lower limb peripheral nerve blockade were included in the training programme, namely sciatic nerve block at the popliteal fossa, saphenous nerve block, and femoral nerve block. Key service drivers underpinning development, rationale for Advanced Clinical Practitioner involvement in lower limb peripheral nerve blockade and governance will also be discussed.

The impact of paravertebral nerve blockade on postoperative surgical site wound pain management in patients undergoing video-assisted thoracoscopic surgery for pulmonary carcinoma resection.

Management of postoperative pain is of vital importance for patients undergoing Video-Assisted Thoracoscopic Surgery (VATS) for Pulmonary Carcinoma Resection. The study evaluates the impact of Paravertebral Nerve Blockade (PNB) in conjunction with general anaesthesia on postoperative pain relief, as compared with general anaesthesia alone. A retrospective analysis was carried out from May 2020 to May 2023, involving 100 patients with pathologically confirmed pulmonary carcinoma. The patients were divided into two groups: a control group that received general anaesthesia and an observation group that received a combination of general anaesthesia and PNB. The intensity of postoperative pain was assessed at various time intervals using the visual analogue scale (VAS), while the effectiveness of patient-controlled analgesia was also evaluated. Additionally, the study examined the incidence rates of chronic pain in the postoperative period. Statistical analysis was performed using IBM SPSS version 27.0. Significant reductions in VAS scores for both resting and cough-induced pain were observed in the observation group at 2 and 6 h post-operation (p < 0.01). However, the difference diminished over time. The observation group had fewer patient-controlled analgesia activations and required lower dosages of hydromorphone at both 24- and 48-h post-operation. The incidence of chronic pain was also significantly lower in the observation group (24.00%) compared with the control group (54.00%) (p < 0.01). PNB, when administered in combination with general anaesthesia, significantly reduces immediate postoperative pain and the requirement for additional analgesics in patients undergoing VATS for pulmonary carcinoma resection. The effect diminishes over time but has a lasting impact on reducing the incidence of chronic postoperative pain.

When the Lung Refuses to Expand: A Deep Dive Into a Pneumothorax Ex Vacuo Case.

Pneumothorax ex vacuo and trapped lung represent challenging clinical entities, especially in the context of pre-existing comorbidities. This case report outlines the diagnostic and management pathway of a 38-year-old patient with cerebral palsy who initially presented with empyema. Following the evacuation of the empyema, the patient developed pneumothorax ex vacuo, a rare phenomenon occurring due to a vacuum-like negative intrapleural pressure initiated by lung collapse. Initially suspected to have an infectious etiology based on laboratory findings, the patient was later found to have a large hydropneumothorax through a combination of imaging, laboratory studies, and clinical evaluations without confirming infection or malignancy. Despite interventions including Tissue Plasminogen Activator (TPA) and Deoxyribonuclease (DNAse) administration to facilitate pleural drainage, the patient's condition persisted, necessitating a surgical intervention that evolved from a minimally invasive video-assisted thoracoscopic surgery (VATS) to a more invasive thoracotomy due to unforeseen pleural thickening. The patient's pre-existing condition of cerebral palsy increased his susceptibility to respiratory complications, including empyema, due to the risk of aspiration. This case highlights the importance of a multidisciplinary approach in managing such complex clinical scenarios. It also serves as a clinical reminder that pneumothorax ex vacuo is generally benign and does not typically require chest tube placement, as the primary issue is an unexpandable lung that is unresponsive to pleural drainage. The report emphasizes the need for flexible surgical planning and robust postoperative management to optimize patient outcomes. It also clarifies the distinct pathophysiology of pneumothorax ex vacuo compared to primary or secondary pneumothorax, advocating for a comprehensive diagnostic approach and the crucial role of a multidisciplinary team in the management of such intricate cases.

Vagal Nerve Therapy in the Management of Obesity: A Systematic Review and Meta-Analysis.

INTRODUCTION: The vagus nerve has an important role in satiety, metabolism, and autonomic control in upper gastrointestinal function. However, the role and effects of vagal nerve therapy on weight loss remain controversial. This systematic review and meta-analysis assessed the effects of vagal nerve therapy on weight loss, body mass index (BMI), and obesity-related conditions. METHODS: MEDLINE, EMBASE, and CINAHL databases were searched for studies up to April 2022 that reported on percentage excess weight loss (%EWL) or BMI at 12 months or remission of obesity-related conditions following vagal nerve therapy from January 2000 to April 2022. Weighted mean difference (WMD) was calculated, meta-analysis was performed using random-effects models, and between-study heterogeneity was assessed. RESULTS: Fifteen studies, of which nine were randomised controlled trials, of 1,447 patients were included. Vagal nerve therapy led to some improvement in %EWL (WMD 17.19%; 95% confidence interval [CI]: 10.94-23.44; p < 0.001) and BMI (WMD -2.24 kg/m2; 95% CI: -4.07 to -0.42; p = 0.016). There was a general improvement found in HbA1c following vagal nerve therapy when compared to no treatment given. No major complications were reported. CONCLUSIONS: Vagal nerve therapy can safely result in a mild-to-moderate improvement in weight loss. However, further clinical trials are required to confirm these results and investigate the possibility of the long-term benefit of vagal nerve therapy as a dual therapy combined with standard surgical bariatric interventions.

Effect of obturator nerve block during transurethral resection of bladder tumors on the disease recurrence, progression and surgery outcomes.

OBJECTIVE: In our study, we aimed to evaluate the effect of the obturator nerve block (ONB) on the operation time, duration of hospital stay, complete resection, presence of muscle tissue in the pathology, second resection, recurrence, and progression, when applied in addition to spinal anesthesia in patients with primary bladder lateral wall tumor and Transurethral Resection of Bladder Tumor (TURBT) was planned. MATERIALS AND METHODS: Seventy patients with bladder lateral wall tumors were included in the study. In addition, ONB was applied to 35 of the patients who underwent spinal anesthesia. The two groups were compared in terms of obturator reflex development, perforation, complete resection, presence of muscle tissue in pathology samples, need for second resection, need for second resection due to inadequate muscle tissue, and 1 year recurrence and progression rates. RESULTS: When the two groups were compared for obturator reflex and bladder perforation, both were found to be lower in the ONB group (p = 0.002, p = 0.198, respectively). The rate of complete resection and the presence of muscle tissue in the pathology samples were higher in the ONB group (p = 0.045, p = 0.034, respectively). The rates of second resection and second resection due to inadequate muscle tissue were found to be higher in the group without ONB (p = 0.015, p = 0.106, respectively). In the 1-year follow-up, the recurrence rate was significantly lower in the ONB group (p < 0.001), while there was no significant difference between the progression rates (p = 0.106). CONCLUSION: In our study, we found out that ONB applied in addition to spinal anesthesia increases the rate of complete and muscle tissue resection by decreasing the obturator reflex, and causes a significant reduction in the need for second resection and tumor recurrence.

Comparison of the Effect of Intercostobrachial Nerve Block with and Without Ultrasound Guidance on Tourniquet Pain After Axillary Block of Brachial Plexus: A Randomized Clinical Trial.

Background: A tourniquet is used to control bleeding in the surgical field. Because part of the inner arm is innervated by the intercostobrachial nerve (ICBN), a tourniquet can cause intolerable pain. Objectives: The present study aimed to compare the effect of ICBN block with and without ultrasound (US) guidance on tourniquet pain after axillary block. Methods: This study was performed on 60 patients who were candidates for surgery. The patients were divided into 3 groups: the control group (n = 22), the traditional ICBN (TICBN) blockade group (n = 19), and the US-guided ICBN blockade group (n = 19). After the intervention, the duration of the onset and intensity of pain was recorded for all patients according to the Numeric Rating Scale (NRS). Data analysis was performed using SPSS. Results: No significant differences were observed in demographic variables between the 3 groups (P > 0.05). The pain intensity in the TICBN blockade (P = 0.001) and US-guided ICBN blockade (P = 0.001) groups was significantly less than in the control group. The mean duration of pain onset was significantly higher in the TICBN blockade (P = 0.021) and US-guided ICBN blockade (P = 0.013) groups than in the control group. No significant difference was observed in the mean of pain intensity (P = 0.48) and the mean duration of pain onset (P = 0.44) between the US-guided ICBN blockade and TICBN blockade groups. Conclusions: The pain caused by a tourniquet can be managed by ICBN block during hand and forearm surgery. It is recommended to use US guidance for more success and safety.

The effects of greater occipital nerve blockage with lidocaine on sleep characteristics in chronic migraine patients.

PURPOSE: The aim of our study was to determine the effects of greater occipital nerve block (GONB) with lidocaine on sleep characteristics in patients with chronic migraine. MATERIALS AND METHODS: Twenty female patients who underwent GONB with lidocaine were included in the study. The Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), Pre-Sleep Arousal Scale (PSAS), Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS), Restless Legs Syndrome Severity Scale (RLSSS), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and headache diary results before and after the treatment of the patients were compared. RESULTS: We included 20 patients (all females) in our study. The mean age was 35.80 ± 8.82 years (range 24-50). After GON blockade, the number of days with pain (p < 0.001), duration of pain (p < 0.001), and Visual Analog Scale (VAS) score (p < 0.001) were significantly lower than before. After GONB, BDI (p = 0.007), BAI (p = 0.022), ISI (p = 0.009), and PSQI (p = 0.026) scores were significantly lower than before. After GONB, sleep quality was better than before (p = 0.035). CONCLUSION: This study showed that GONB with lidocaine can improve sleep quality, insomnia, and symptoms of depression and anxiety while reducing migraine headache.

Periarticular Injection Versus Peripheral Nerve Blockade in Bilateral Total Hip Arthroplasty.

Pain control after total hip arthroplasty is associated with patient satisfaction, early discharge, and improved surgical outcomes. Two commonly utilized opioid-reducing analgesic modalities are periarticular injection (PAI) by surgeons and motor-sparing peripheral nerve block (PNB) by anesthesiologists. We present a case contrasting PAI and PNB in a single patient undergoing bilateral total hip arthroplasty. For the left hip, the patient received preoperative transmuscular quadratus lumborum, femoral nerve, and lateral femoral cutaneous nerve blocks using a combination of low-concentration local anesthetic and glucocorticoids. For the right hip, the patient received an intraoperative PAI with liposomal bupivacaine. The patient's pain scores and recovery were evaluated for three months postoperatively. The patient's pain scores on postoperative day (POD) zero to five were consistently lower in the left hip than in the right hip. For this patient undergoing bilateral hip replacement, preoperative PNBs were superior to PAI for postoperative pain control.

Vasovagal Syncope and Transient Asystole During Peripheral Nerve Blockade.

Vasovagal syncope has been associated with chronic pain procedures, phlebotomy, and musculoskeletal injections. While vasovagal syncope is commonly associated with interventional pain procedures, its occurrence during peripheral nerve block procedures has not been reported. We report a case of vasovagal syncope leading to transient asystole in a patient undergoing a lower extremity peripheral nerve block procedure. The episode resolved after halting the procedure and administering ephedrine, atropine, and intravenous fluids.

Regional anesthesia improves inpatient but not outpatient opioid demand in tibial shaft fracture surgery.

BACKGROUND: Patients undergoing operative treatment of tibial shaft fractures have considerable pain largely managed with opioids. Regional anesthesia (RA) has been increasingly used to reduce perioperative opioid use. METHODS: This was a retrospective study of 426 patients that underwent operative treatment of tibial shaft fractures with and without RA. Inpatient opioid consumption and 90-day outpatient opioid demand were measured. RESULTS: RA significantly decreased inpatient opioid consumption for 48 h post-operatively (p = 0.008). Neither inpatient use after 48 h nor outpatient opioid demand differed in patients with RA (p > 0.05). CONCLUSIONS: RA may help with inpatient pain control and reduce opioid use in tibial shaft fracture. LEVEL OF EVIDENCE: Level III, retrospective, therapeutic cohort study.

Greater occipital nerve blockade for the preventive treatment of chronic migraine: A randomized double-blind placebo-controlled study.

BACKGROUND: Greater occipital nerve blockade for the prevention of chronic migraine has a limited evidence base. A robust randomized double-blind, placebo-controlled trial is needed. METHODS: This double-blind, placebo-controlled, parallel-group trial, following a baseline period of four weeks, randomly assigned patients of chronic migraine 1:1 to receive four-weekly bilateral greater occipital nerve blockade with either 2 ml of 2% (40 mg) lidocaine (active group) or 2 ml of 0.9% saline (placebo) injections for 12 weeks. The primary and key secondary efficacy endpoints were a change from the baseline in the mean number of headache and migraine days and the achievement of ≥50% reduction in headache days from baseline across the weeks 9-12 respectively. Safety evaluations included the documentation and reporting of serious and other adverse events. RESULTS: Twenty-two patients each were randomly allocated to the active and placebo group. Baseline demography and clinical characteristics were similar between the two groups. Mean headache and migraine days at baseline (±SD) were 23.4 ± 4.4 and 15.6 ± 5.7 days in the active group and 22.6 ± 5.0 and 14.6 ± 4.6 days in the placebo group respectively. The active group compared to the placebo had a significantly greater least-squares mean reduction in the number of headache and migraine days (-4.2 days [95% CI: -7.5 to -0.8; p = 0.018] and -4.7 days [95%CI: -7.7 to -1.7; p = 0.003] respectively). 40.9% of patients in the active group achieved ≥50% reduction in headache days as compared with 9.1% of patients receiving a placebo (p = 0.024). Overall, 64 mild and transient adverse events were reported by 16 patients in the active group and 15 in the placebo. No death or serious adverse events were reported. CONCLUSION: Four-weekly greater occipital nerve blockade with 2% lidocaine for 12 weeks was superior to placebo in decreasing the average number of headache and migraine days in patients with chronic migraine with a good tolerability profile.Clinical trial.gov no. CTRI 2020/07/026709.

Closing the gap: artificial intelligence applied to ultrasound-guided regional anaesthesia.

The role of artificial intelligence in ultrasound-guided regional anaesthesia is explored in a recent study by Bowness and colleagues, published in the British Journal of Anaesthesia. The investigators showed that non-expert ability to identify key sono-anatomical structures was improved with the assistance of proprietary artificial intelligence software. Whether such software could increase learning efficiency, and thereby patient access, to regional anaesthesia, will require further study.

A Practical Guide to Lower Extremity Nerve Blocks for the Sports Medicine Surgeon.

BACKGROUND: Peripheral nerve blocks (PNBs) are vital in the administration of surgical analgesia and have grown in popularity for use in lower extremity arthroscopic procedures because of their capacity to safely and effectively control pain. The number and specificity of PNBs, however, have made choosing the best option for a procedure nebulous for orthopaedic surgeons. PURPOSE: To present a narrative literature review of the PNBs available for arthroscopic hip and knee procedures that is adapted to an audience of orthopaedic surgeons. STUDY DESIGN: Narrative literature review. METHODS: A combination of the names of various lower extremity PNBs AND "hip arthroscopy" OR "knee arthroscopy" was used to search the English medical literature including PubMed, Cochrane Library, ScienceDirect, Embase, and Scopus. Placement technique, specificity of blockade, efficacy, and complications were assessed. Searches were performed through May 2, 2021. RESULTS: A total of 157 studies were included in this review of lower extremity PNBs. Femoral nerve, lumbar plexus, sciatic nerve, and fascia iliaca compartment blocks were most commonly used in arthroscopic hip surgery, while femoral nerve, 3-in-1, and adductor canal blocks were preferred for arthroscopic knee surgery. Each block demonstrated a significant benefit (P > .05) in ≥1 of the following outcomes: intraoperative morphine, pain scores, nausea, and/or opioid consumption. Combination blocks including the lateral femoral cutaneous nerve block, obturator nerve block, quadratus lumborum block, and L1 and L2 paravertebral block have also been described. Complication rates ranged from 0% to 4.8% in those administered with ultrasound guidance. The most commonly reported complications included muscular weakness, postoperative falls, neuropathy, intravascular and intraneural injections, and hematomas. CONCLUSION: When administered properly, PNBs were a safe and effective adjuvant method of pain control with a significant potential to limit postoperative narcotic use. While blockade choice varies by surgeon preference and procedure, all PNBs should be administered with ultrasound guidance, and vigilant protocols for the risk of postoperative falls should be exercised in patients who receive them.

Reevaluation of the topographical anatomy of the mid-thigh: A magnetic resonance and ultrasound imaging study.

Adductor canal (AC) and sciatic nerve (SN) blockades are commonly used during total knee arthroplasties for postoperative pain control. Medical professionals have begun to utilize single injection combined regional anesthesia methods due to increased patient comfort. In this study, we examined the topographical anatomy of the mid-thigh, which is recommended as the appropriate intervention level for combined AC and SN blockades, in order to provide a safe approach for clinicians. We examined 184 thigh magnetic resonance images (MRI) from 98 patients. We measured the diameter of the mid-thigh, anterior thigh muscle thickness, subcutaneous adipose tissue thickness, and SN depth on the MRIs. We obtained ultrasound (US) images of the vastoadductor membranes (VAM) of 26 volunteers, and measured the vertical distances between the greater trochanter and the adductor tubercle (A) and the greater trochanter and the upper edge of the VAM (B). We then proportioned B to A in order to determine in which part of the thigh the AC was located. The AC was in the distal third of the thigh, and the SN's depth was located in the third quarter of the thigh's diameter. Only the adductor magnus, and no neurovascular structure, was at risk of injury between the AC and the SN. The upper edge of the VAM was 6.5 cm below the mid-thigh, therefore it is not appropriate to suggest performing an AC blockade at mid-thigh. We think that it is safe to perform a combined AC and SN blockade in a single injection in selected patients.