Supraclavicular Nerve Research Articles

Activation thresholds for electrical phrenic nerve stimulation at the neck: evaluation of stimulation pulse parameters in a simulation study

Abstract Objective. Phrenic nerve stimulation reduces ventilator-induced-diaphragmatic-dysfunction, which is a potential complication of mechanical ventilation. Electromagnetic simulations provide valuable information about the effects of the stimulation and are used to determine appropriate stimulation parameters and evaluate possible co-activation.
Approach. Using a multiscale approach, we built a novel detailed anatomical model of the neck and the phrenic nerve. The model consisted of a macroscale volume conduction model of the neck with 13 tissues, a mesoscale volume conduction model of the phrenic nerve with three tissues, and a microscale biophysiological model of axons with diameters ranging from 5 to 14 μm based on the McIntyre-Richardson-Grill-model for myelinated axons. This multiscale model was used to quantify activation thresholds of phrenic nerve fibers using different stimulation pulse parameters (pulse width, interphase delay, asymmetry of biphasic pulses, pulse polarity, and rise time) during non-invasive electrical stimulation. Electric field strength was used to evaluate co-activation of the other nerves in the neck.
Main results. For monophasic pulses with a pulse width of 150 μs, the activation threshold depended on the fiber diameter and ranged from 20 to 156 mA, with highest activation threshold for the smallest fiber diameter. The relationship was approximated using a power fit function x^−3. Biphasic (symmetric) pulses increased the activation threshold by 25 to 30 %. The use of asymmetric biphasic pulses or an interphase delay lowered the threshold close to the monophasic threshold. Possible co-activated nerves were the more superficial nerves and included the transverse cervical nerve, the supraclavicular nerve, the great auricular nerve, the cervical plexus, the brachial plexus, and the long thoracic nerve.
Significance. Our multiscale model and electromagnetic simulations provided insight into phrenic nerve activation and possible co-activation by non-invasive electrical stimulation and provided guidance on the use of stimulation pulse types with minimal activation threshold.

Infraclavicular versus supraclavicular nerve block for upper limb surgeries: A meta-analysis.

The impact of infraclavicular versus supraclavicular nerve block on the analgesia for upper limb surgeries is unclear. This meta-analysis and systematic review aims to study the analgesic efficacy of infraclavicular versus supraclavicular nerve block for upper limb surgeries. We searched several databases including PubMed, EMbase, Web of science, EBSCO and Cochrane library databases from inception to December 2023, and randomized controlled trials (RCTs) assessing the effect of infraclavicular versus supraclavicular nerve block for upper limb surgeries were included. We excluded studies reporting other nerve block approaches. The methodological quality of the included studies was evaluated by the modified Jadad scale. Standard mean difference with 95% confidence interval (CI) was used to assess continuous outcomes. This meta-analysis was conducted by the fixed-effect model or random-effect model based on the heterogeneity. Eight RCTs and 725 patients were included in this meta-analysis. Compared with supraclavicular nerve block for upper limb surgeries, infraclavicular nerve block was able to significantly increase duration of motor block (SMD = 0.34; 95% CI = 0.12 to 0.56) and decrease readiness for surgery (SMD = -0.43; 95% CI = -0.77 to -0.10), but showed similar duration of sensory block (SMD = 0.17; 95% CI = -0.05 to 0.39), block performance time (SMD = -0.14; 95% CI = -0.51 to 0.22), onset of sensory blockade (SMD = -0.13; 95% CI = -0.59 to 0.33) and onset of motor blockade (SMD = -0.17; 95% CI = -0.26 to 0.12). No high heterogeneity was seen among the included studies. Infraclavicular nerve block may be superior to control the analgesia for upper limb surgeries than supraclavicular nerve block.

Minimally Invasive Plate Osteosynthesis with Mini-Open Technique and Supraclavicular Nerve Preservation Reduces Postoperative Numbness in Acute Displaced Midshaft Clavicle Fracture

Background: Minimally invasive plate osteosynthesis (MIPO) for clavicular shaft fracture yields favorable functional outcomes and results in less surgery-related soft tissue injury than other techniques. Anterior chest and shoulder skin numbness, a common complication after open reduction and plate fixation, is related to injury to the supraclavicular nerves. We propose MIPO combined with a mini-open approach without fluoroscopy for nerve preservation to minimize the risk of postoperative numbness compared with traditional open plating without nerve preservation. Methods: A total of 59 patients were retrospectively identified, with a follow-up period of 6 months. Thirty-two patients underwent MIPO with mini-open and nerve preservation technique (MIPO group), and 27 patients underwent traditional open plating without nerve preservation (open group). Constant–Murley shoulder outcome score, operation time, wound length, skin numbness, and number of implant removals were compared between the groups. Results: The MIPO group had significantly lower rates of anterior chest and shoulder skin numbness than the open group (MIPO: 12.5% vs. open: 55.6%; p < 0.001). Operation time was significantly longer in the MIPO group than in the open group (MIPO: 109.38 ± 18.83 vs. open: 81.48 ± 18.85; p < 0.001). Wound length was significantly shorter in the MIPO group than in the open group (MIPO: 4.73 ± 0.79 vs. open: 9.76 ± 1.64; p < 0.001). Both groups had similarly excellent Constant–Murley shoulder scores. There were significantly fewer implant removals in the MIPO group than in the open group (MIPO: 6.3% vs. open: 25.9%; p = 0.036). Neither group experienced any infection, implant failure, or nonunion. Conclusions: Our technique combining MIPO with the mini-open approach and supraclavicular nerve preservation yields a lower incidence of skin numbness than traditional open plating without nerve preservation.

ID: 341882 Bimodal Sensory and Motor 60-day PNS of Suprascapular, Supraclavicular and Axillary Nerves for Shoulder Pain

ID: 341882 Bimodal Sensory and Motor 60-day PNS of Suprascapular, Supraclavicular and Axillary Nerves for Shoulder Pain

776. THREE-FIELD LYMPHADENECTOMY IN ESOPHAGEAL CANCER: EXPERIENCE OF A PORTUGUESE TERTIARY CENTER

Abstract Background The American Joint Committee for Cancer (AJCC) and the Japanese Esophagus Society (JES) differ in the N classification for esophageal cancer, with the former considering the presence of disease in the supraclavicular lymph nodes as M1, and the latter classifying it as loco-regional disease in thoracic esophageal tumors. Patients who would be excluded from a curative intent treatment strategy by the AJCC classification may be candidates for surgery with lymphadenectomy of nodal groups 101 and 104 (JES). Our goal is to understand the impact of three-field lymphadenectomy on morbidity, loco-regional control and overall survival in patients with esophageal cancer. Methods A retrospective cohort study was conducted using data from a prospective database from a single center, which included all consecutive patients undergoing esophagectomy for cancer with either two-field total thoracic lymphadenectomy or three-field lymphadenectomy, between January 2019 and December 2023. Three-field lymphadenectomy was performed for clinical supraclavicular and recurrent nerve nodal involvement and for proximal third tumors. We assessed the morbidity and mortality of both types of surgery, and loco-regional and distant recurrence and overall survival for both groups. Results Of the 279 esophagectomies for cancer, 137 were included for analysis. The median age was 65 years, with 84% males. 58,4% had squamous cell carcinoma and 41,6% adenocarcinoma. 34.3% of the patients had a 3-field lymphadenectomy, 27,7% of these for supraclavicular N+ and 34% for recurrent nerve N+. Conclusion In this large single-center cohort, patients with significant lymph node involvement, treated with esophagectomy and three-field lymphadenectomy, demonstrated comparable loco-regional control and overall survival to more favorable cases, with no statistically significant increase in morbidity and mortality.

An unilateral double fenestration of the right external jugular vein: a rare variant.

This report presents a rare anatomical variation, double fenestration of the External jugular vein on the right side. During the routine dissection of a male cadaver aged 60 years, we observed a unilateral large double fenestration of the External jugular vein on the right side. After its formation from the posterior division of the retromandibular and posterior auricular veins, External jugular vein descended in the posterior triangle of neck. Here, it divided into medial, intermediate, and lateral veins that united again before draining into the subclavian vein. Lateral vein was the largest (7.2cm) and intermediate and medial veins were measuring 6.4cm each. Two large fenestrations, measuring 5.8cm each, arranged like a "double bubble" were seen in the External jugular vein extending from fourth to sixth cervical (C4 to C6) vertebrae. The medial branch of supraclavicular nerve was seen passing superficial to the distal part of External jugular vein. On the left side, the course of External jugular vein showed a standard pattern. Surgeons must be acquainted with the varied anatomy of the superficial neck veins to prevent major bleeding during operative procedures, including carotid endarterectomy, flap operations, & central venous catheterisation.

Feasibility and safety of ultrasound-guided supra-clavicular block in children

BackgroundUltrasound-guided supra-clavicular nerve block (SCNB) has regained interest in adults but remains underutilized in pediatrics. This case series aims to evaluate the efficacy and safety of ultrasound-guided SCNB in children undergoing upper-extremity surgery. MethodsProspective observational case series, the inclusion criteria were children over one year old who were scheduled for elective upper-extremity surgery. After induction of general anesthesia, an ultrasound-guided SCNB was performed. A dose of 0.2–0.5 ml/kg of bupivacaine 0.25 % or ropivacaine 0.2 % was administered all around the brachial plexus. In case of postoperative pain, 15 mg kg-1 of paracetamol + 10 mg kg-1 of ibuprofen were administered. The primary outcome measure was the success and safety of the block. Secondary outcomes were time to first analgesia administration and duration of motor blockade. ResultsThirty-three patients were included. Median age and weight were 6 [2.75,9.75] years and 24 [16,35] kg, respectively with a sex ratio of 3.1. Bupivacaine 0.25 % was used in the majority of cases (N = 24). The overall duration to complete block performance was 170 [120,300] seconds. A single attempt was sufficient for the majority of children, with a block success rate of 100 %. No incidents were reported during block performance. Postoperatively, time to the first analgesic request was 10 [8,12.5] hours. Twenty-five patients developed a motor block, with a duration of 4 [0.5,5] hours. Bupivacaine 0.25 % was associated with higher incidence of motor blockade (p = 0.002). ConclusionsUltrasound-guided SCNB appears to be an effective and safe technique in children. Further studies using lower doses of bupivacaine could help reduce the incidence of motor block.

Innervation of the human sternoclavicular joint.

The sternoclavicular joint (SCJ) functions as the basal joint of the entire upper limb and must move in the proper pattern for normal scapular motion. Afferent sensations from joints, such as proprioception and pain sensation, are important for maintaining the proper motion and condition of joints. Detailed anatomical data are useful for discussing injuries or surgeries that impair the afferent nerve to the SCJ. Nerve branches to SCJs were examined on 12 sides, and the subclavian nerve was investigated on six sides to clarify whether it innervates this joint. On seven of the 12 sides, the SCJ was innervated by two nerves, (1) a branch from the medial supraclavicular nerve that ran medially along the clavicle and (2) a branch from the lateral pectoral nerve that innervated the clavicular head and upper part of the sternocostal head of the pectoralis major. This branch ran medially behind the clavicular head of the pectoralis major and reached the SCJ. In the remaining five sides, the SCJ was innervated solely by the branch from the medial supraclavicular nerve. Subclavian nerves ended within the subclavius muscle or periosteum of the clavicle and were separate from the SCJs. Our data on the route of nerve branches to the SCJ suggest that injury or surgery, such as clavicle fracture or resection of the clavicular head of the pectoralis major for myocutaneous flap transfer, can impair the SCJ's afferent nerve supply.

Comparison of supraclavicular block with infraclavicular block for distal arm surgeries: A meta-analysis of randomized controlled studies.

Supraclavicular and infraclavicular nerve block are commonly used for the analgesia of distal arm surgeries, and this meta-analysis aims to compare their analgesic efficacy for distal arm surgeries. We searched several databases including PubMed, Embase, Web of Science, EBSCO, and Cochrane library databases, and selected the randomized controlled trials exploring the analgesic efficacy of supraclavicular block versus infraclavicular block for distal arm surgeries. This meta-analysis was conducted using the random-effect or fixed-effect model based on the heterogeneity. Six randomized controlled trials were included in this meta-analysis. Compared with infraclavicular nerve block for distal arm surgeries, supraclavicular nerve block was associated with substantially reduced complete sensory block (odds ratio [OR] = 0.41; 95% confidence interval [CI] = 0.19-0.88; P = .02) and block performance time (standard mean difference [SMD] = -3.06; 95% CI = -5.82--0.31; P = .03), but had no effect on duration of analgesia (SMD = -0.15; 95% CI = -0.49-0.18; P = .36), time to sensory block (SMD = -0.41; 95% CI = -2.28-1.47; P = .67), vascular puncture (OR = 1.03; 95% CI = 0.11-10.05; P = .98) or adverse events (OR = 0.70; 95% CI = 0.12-4.04; P = .69). Infraclavicular nerve block may be superior to supraclavicular nerve block for the analgesia of distal arm surgeries but needs increased block performance time.

Anatomical variations of the brachial plexus in adult cadavers: A descriptive study and clinical significance.

Brachial plexus injury is recognized as one of the most severe clinical challenges due to the complex anatomical configuration of the brachial plexus and its propensity for variation, which complicates safe clinical interventions. This study aimed to ascertain the prevalence and characterize the types of brachial plexus variations, and to elucidate their clinical implications. We conducted meticulous dissections of 60 formalin-fixed cadavers' upper arm, axilla and lower neck to reveal and assess the roots, trunks, divisions, cords, and branches of the brachial plexus. The pattern of branching was noted by groups of dissecting medical students and confirmed by the senior anatomists. The variations discovered were record and photographed using a digital camera for further analysis. Variations in the brachial plexus were identified in 40 of the 60 cadavers, yielding a prevalence rate of 66.7%. These variations were classified into root anomalies (2.1%), trunk anomalies (8.5%), division anomalies (2.1%), and cord anomalies (4.3%). Notably, anomalies in communicating branches were observed in 39 cadavers (83.0%): 14 with bilateral anomalies, 14 with anomalies on the left side, and 11 on the right side. These communicating branches formed connections between the roots and other segments, including trunks, cords, and terminal nerves, and involved the median, musculocutaneous, and ulnar nerves. The frequency and diversity of brachial plexus variations, particularly in communicating branches, are significant in cadavers. It is imperative that these variations are carefully considered during the diagnostic process, treatment planning, and prior to procedures such as supraclavicular brachial plexus blocks and nerve transfers, to mitigate the risk of iatrogenic complications.

A randomised trial comparing block characteristics of a mixture versus sequential injections of lignocaine and ropivacaine for supraclavicular brachial plexus nerve block in patients undergoing upper limb surgery.

There is no consensus on the appropriate use of mixtures of local anaesthetic drugs in various combinations for nerve blocks. We intended to compare short-acting lignocaine and long-acting ropivacaine as a mixture versus undiluted sequential injections on block characteristics of ultrasound-guided (USG) supraclavicular brachial plexus block for upper limb surgeries. A double-blinded randomised study was conducted on 64 adult patients scheduled for upper limb surgery who received 15 mL each of 2% lignocaine with adrenaline and 0.75% ropivacaine as a 1:1 mixture in the mixed group (Group M) or sequential injections in the sequential group (Group S) by using a USG technique. The primary outcome was the percentage of participants with complete four nerve sensory blocks at 10 minutes post block injection. Secondary outcomes were sensory and motor block characteristics till 30 minutes, total duration of analgesia, sensory and motor block, and complications. Demographic characteristics and time taken for the procedure were similar. The percentage of participants with a complete four-nerve sensory block at 10 minutes was higher in Group S (69%) versus Group M (41%) (P = 0.04). Complete sensory and motor block rates were similar at 30 minutes. The block procedure time, total duration of analgesia, and sensory and motor block were similar in both groups. There were no major complications. Sequential lignocaine-ropivacaine, compared to the mixed injection technique, has a higher initial rate of sensory and motor block onset with a similar total block duration.

Comparative analysis of fentanyl and dexmedetomidine as an adjuvant to ropivacaine in supraclavicular nerve block procedures involving upper limbs

Comparative analysis of fentanyl and dexmedetomidine as an adjuvant to ropivacaine in supraclavicular nerve block procedures involving upper limbs

Case Report of Acupotomy Treatment for Supraclavicular Nerve Entrapment

Case Report of Acupotomy Treatment for Supraclavicular Nerve Entrapment

Intercostal Nerve Transfer for Biceps Reinnervation in Obstetrical Brachial Plexus Palsy: A Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Individual Patient Data Systematic Review using Individualized Fusion and Comparison to Supraclavicular Exploration and Nerve Grafting.

The objective of this study was to search existing literature on nerve reconstruction surgery in patients with obstetric brachial plexus palsy to determine whether treatment with supraclavicular exploration and nerve grafting produced better elbow flexion outcomes compared to intercostal nerve transfer. This study was a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis for Individual Patient Data guidelines. A systematic search was conducted using multiple databases. An ordinal regression model was used to analyze the effect of using supraclavicular exploration and nerve grafting or intercostal nerve on elbow flexion with the two scores measured: elbow flexion Medical Research Council scores and Toronto active movements scale scores for elbow flexion. A final patient database from 6 published articles consisted of 83 supraclavicular exploration and nerve grafting patients (73 patients with Medical Research Council and 10 patients with Toronto score) and 7 published articles which consisted of 131 intercostal nerve patients (84 patients with Medical Research Council and 47 patients with Toronto scores). Patients who underwent supraclavicular exploration and nerve grafting presented with an average Medical Research Council score of 3.9 ± 0.72 and an average Toronto score of 6.2 ± 2.2. Patients who underwent intercostal nerve transfer presented with an average Medical Research Council score of 3.9 ± 0.71 and an average Toronto score of 6.4 ± 1.2. There was no statistical difference between supraclavicular exploration and nerve grafting and intercostal nerve transfer when utilizing Medical Research Council elbow flexion scores (ordinal regression: 0.3821, standard error: 0.4590, p = 0.2551) or Toronto Active Movement Scale score for elbow flexion (ordinal regression: 0.7154, standard error: 0.8487, p = 0.2188). Regardless of surgical intervention utilized (supraclavicular exploration and nerve grafting or intercostal nerve transfers), patients had excellent outcomes for elbow flexion following obstetric brachial plexus palsy when utilizing Medical Research Council or Toronto scores for elbow flexion. The difference between these scores was not statistically significant. Therapeutic Study: Investigating the Result of Treatment/level III.

Analgesic Efficacy of Dexmedetomidine as an Adjuvant to Ropivacaine in Supraclavicular Brachial Plexus Block for Upper Limb Surgeries: A Prospective Randomized Study

Background and Aims: The primary aim of this randomized controlled study was to evaluate the effect of the addition of dexmedetomidine to ropivacaine on the onset and duration of sensory and motor blockade and the duration of analgesia in patients undergoing upper limb surgeries under supraclavicular brachial plexus block. Materials and Methods: A total of 100 patients of age 18–55 years, planned for elective upper limb surgeries under supraclavicular brachial plexus block using a nerve stimulator, were randomly allocated into two groups. Group 1 (n = 50) received 30 mL 0.5% ropivacaine and 1 mL normal saline and Group 2 (n = 50) received 30 mL 0.5% ropivacaine and 1 μg/kg of dexmedetomidine. The onset and duration of sensory and motor block, duration of analgesia, and adverse events during the perioperative period were noted. Results: The onset of sensory and motor block in Group 1 (16. 26 ± 2.23 and 21.68 ± 2.90 min) was slower than those in Group 2 (9.12 ± 2.40 and 12.68 ± 2.62 min), (<0.001). The duration of sensory and motor block in Group 1 was significantly shorter than those in Group 2 (P < 0.001). The duration of analgesia in Group 1 (402.80 ± 28.21 min) was shorter than that in Group 2 (981.00 ± 92.26 min; P < 0.001). There was no statistically significant difference between the two groups in the incidence of the side effects, except in the incidence of sedation which is significantly higher in Group 2, (P < 0.001). Conclusion: Dexmedetomidine with ropivacaine for supraclavicular nerve block resulted in earlier onset and prolonged duration of the sensorimotor blockade and provided a longer pain-free postoperative period without significant hemodynamic alterations.

Supraclavicular nerve sparing versus sacrifice during open reduction internal fixation of acute midshaft clavicle fracture

BackgroundThe branches of the supraclavicular nerve are often sacrificed during open reduction and internal fixation (ORIF) for clavicle fracture. No consensus exists on whether the supraclavicular nerve should be routinely identified and protected during ORIF.MethodsWe developed a simple method to make nerve sparing easier; Wide-Awake Local Anesthesia No Tourniquet (WALANT) solution is locally injected prior to the surgical incision being made. This retrospective study enrolled 340 patients and divided them into supraclavicular-nerve-sparing (n = 45) and supraclavicular-nerve-sacrifice (n = 295) groups. Surgical outcomes—including operative time, estimated blood loss, postoperative pain, union rate, time to union, functional score, paresthesia, complications, implant removal rate, and complication rate—were recorded.ResultsIncisional or anterior chest wall numbness and intraoperative blood loss were significantly less (p < 0.001) in the nerve-sparing group. The operative time was similar in the two groups. No significant differences were discovered in QuickDASH score, postoperative pain score, union rate, time to union, implant removal rate, complication rate, or revision rate.ConclusionsOur study demonstrated that the outcomes of supraclavicular nerve sparing during ORIF with WALANT can reduce postoperative incisional and anterior chest wall numbness and intraoperative blood loss without increasing the operative time or complication rate.

Comparitive Study between Dexamethasone versus Fentanyl as Adjuvant to Local Anesthesia in Supraclavicular Nerve Block in Upper Limb Surgery

Abstract Background Peripheral nerve block as an anesthetic technique plays an important role in modern regional anesthesia. Upper limb surgeries are mostly performed under peripheral blocks such as the brachial plexus block. Peripheral nerve blocks not only provide intra-operative anesthesia, but also extend analgesia in the post-operative period without major systemic side-effects by minimizing stress response and using minimal anesthetic drugs. Objective To evaluate the effects of adding dexamethasone and fentanyl to bupivacaine in ultrasound guided supraclavicular brachial plexus block for upper limb surgery versus bupivacaine alone. Patients and Methods After obtaining approval from the medical ethical committee in Al-Matareya Teaching Hospital, this study was conducted in Al-Matareya Teaching Hospital in cooperation with Ain Shams University. It was include patients undergoing elective upper limb surgery. A written informed consent was obtained from every patient after explaining the procedure. A randomized double-blinded controlled study is thought to be the most suitable design to achieve the study objectives. Results The present study showed that addition of dexamethasone and fentanyl to bupivacaine in ultrasound-guided supraclavicular nerve block shortened the onset times of both sensory and motor blocks and significantly prolonged their duration compared to bupivacaine olny. Conclusion In the current study, the addition of dexamethasone or fentanyl to bupivacaine for supraclavicular brachial plexus block make the onset of sensory &amp; motor block faster and prolongation of motor and sensory block duration and prolongation of duration of analgesia more than using bupivacaine only. But onset of motor and sensory block was shorter in fentanyl group than dexamethasone group and duration of sensory and motor block more in dexamethasone rather than fentanyl.

The Effects of Dexamethasone versus Potassium Chloride as Additives to Local Anesthetic in Supraclavicular Brachial Plexus Block

Abstract Background Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage. Regional anesthesia of the trunk and the extremities an alternative to general anesthesia in many situations. It avoids the unwanted effects of the anesthetic drugs used during general anesthesia and the stress of laryngoscopy and tracheal intubation. Aim of the Work To compare the clinical efficacy of addition of dexamethasone or potassium chloride to local anesthetic solution of bupivacaine and lignocaine on the onset, duration, quality of analgesia, and quality of sensory and motor blockade in supraclavicular brachial plexus block in patients undergoing upper extremity surgeries. Patients and Methods This study is a prospective double – blinded, randomized trial After obtaining approval from the Research Ethical Committee of faculty of medicine Ain shams University, this study was conducted in the operating theaters of Ain shams University Hospital. Results In the current study, it was obvious that: addition of Dexamethasone to bupivacaine in supraclavicular nerve block shortened the onset times of both sensory and motor blocks than add. Addition of Dexamethasone to bupivacaine significantly prolongs both sensory and motor block durations than injecting dexamethasone intravenously. Addition of Dexamesthasone to bupivacaine prolongs the analgesia of brachial plexus block with subsequent consumption of less amount of analgesics than adding Potassium Chloride. Conclusion The use of ultrasonography in performing the supraclavicular nerve block, decreased significantly the incidence of complications such as pneumothorax or intravascular injection and hence, lowered the incidence of systemic toxicity of local anesthetics.

Ultrasonographic visualization of anatomical variations of the supraclavicular nerves.

Typical anatomy of the supraclavicular nerve (SCN) is described as originating from the cervical plexus and dividing into medial, intermediate, and lateral branches. The SCN is vulnerable to injury during clavicular surgery, leading to altered sensation post-operatively. There is also increasing interest in anesthetizing the SCN in shoulder or clavicular surgery. Utilizing a high-frequency (20 MHz) ultrasound probe, 20 healthy volunteers were scanned, giving data for 40 SCNs. For each nerve, anatomical course and branches were graphically plotted using a custom Python 3.8.12 program and Microsoft Excel. Of 40 nerves, only 19 (47.5%) demonstrated a typical course, with the rest showing considerable variability of branching patterns. Crossing branches (CBs) were found in 24 (60%) with a total of 54. Just over half (29, 54.7%) of these crossed the clavicle lateral to its midpoint, with 32 (59.6%) CBs having a diameter of ≥25% compared to that of the SCN main trunk. The distance from the mid-clavicular point at which the branches crossed the clavicle was recorded. This study demonstrated that over half the SCNs had atypical branching patterns with intra-volunteer variability. Preoperative mapping may be useful in preventing injury and subsequent numbness.

Peripheral Nerve Stimulation with a High Frequency Electromagnetic Coupled (HF-EMC) Powered Implanted Neurostimulator with Receiver at the Suprascapular and Supraclavicular Nerves for the Treatment of Chronic Shoulder Pain: Case Report

Background: Over 20% of adults are affected by chronic shoulder pain that can limit the use of the upper extremity and decrease the overall quality of life. Peripheral nerve stimulation (PNS) is an emerging treatment for refractory cases of chronic pain that has been receiving heightened attention in recent years with growing documentation of favorable results. This report discusses a case of chronic shoulder pain effectively managed with PNS. Case Report: A 58-year-old man, with a history of cervical laminectomy presented with persistent pain of the left shoulder, radiating down the medial aspect of the left upper arm to the elbow, and pain along the upper trapezius between the neck and shoulder that did not ease after successful shoulder joint replacement. The pain averaged 8/10 and escalated to 10/10 with arm movement or lifting over 5 pounds. Once agitated, the pain would stay elevated for several hours. The patient eventually withdrew completely from social activities and stopped leaving his home except when absolutely necessary to avoid additional pain brought on by activity. Previous treatments, including physical therapy, opioids, nonsteroidal anti-inflammatory drugs (NSAIDS), and cervical epidural steroid injection, were unsuccessful in managing pain. The patient did, however, achieve relief with peripheral nerve stimulation. Pain scores at 3-month follow-up decreased from 8/10 without and 10/10 with activity to an average of 1/10 with increased activity, complete cessation of pain medication, and reported improvement in quality of life. These results have been maintained at 12 months post-implant. Conclusion: Sub-threshold peripheral nerve stimulation with an externally powered system at the suprascapular and supraclavicular nerves was an effective treatment for a patient suffering from debilitating pain in the shoulder, upper arm, and upper trapezius after a successful, structurally sound shoulder replacement did not reduce persistent chronic pain. Key words: Peripheral nerve stimulation (PNS), chronic pain, suprascapular nerve, supraclavicular nerve, mononeuropathy, upper limb pain, brachial plexus, disorder, shoulder replacement