An uncommon, unilateral motor variation of the intercostobrachial nerve.

The intercostobrachial nerve (ICBN) is commonly defined as a purely sensory nerve supplying the skin of the lateral chest wall, axilla, and medial arm. However, numerous branching patterns and distributions, including motor, have been reported. This report describes an uncommon variant of the right ICBN observed in both an 86-year-old white female cadaver and a 77-year-old white male cadaver. In both cases the ICBN presented with an additional muscular branch, termed the "medial pectoral branch", piercing and therefore innervating the pectoralis major and minor muscles. Clinically, the ICBN is relevant during surgical access to the axilla and can result in sensory deficits (persistent pain/loss of sensory function) to this region following injury. However, damage to the variation observed in these cadavers may result in additional partial motor loss to pectoralis major and minor.

Anatomical Evaluation of a Conventional Pectoralis II Versus a Subserratus Plane Block for Breast Surgery.

BACKGROUND: Pectoralis I and II (Pecs I/Pecs II) blocks are modern regional anesthetic techniques performed in combination to anesthetize the nerves involved in breast surgery and axillary node dissection. Pecs II spread and clinical efficacy is thought to be independent of whether injection occurs between pectoralis minor and serratus anterior or deep to serratus anterior. Injecting deep to serratus anterior onto the rib may be technically easier; however, our clinical experience suggests that this approach may be less effective for axillary dissection. We undertook a cadaveric study to evaluate a subserratus plane approach for use in breast and axillary surgery. METHODS: Ultrasound-guided blocks using methylene blue dye were performed on 4 Genelyn-embalmed cadavers to assess and compare dye spread after a conventional Pecs II and a subserratus plane block at the third rib. RESULTS: Conventional Pecs II injection demonstrated staining of the intercostobrachial nerve, third intercostal nerve, thoracodorsal nerve, long thoracic nerve, medial pectoral, and lateral pectoral nerve. The subserratus plane produced significantly less axillary spread, incomplete staining of the medial pectoral, and very minimal staining of the lateral pectoral nerve. Dye spread was limited to the lateral cutaneous branches of the intercostal nerves in both injections. CONCLUSIONS: In our cadaveric study, injecting deep to serratus plane produced significantly less axillary spread. For breast surgery excluding the axilla, both techniques may be effective; however, for axillary dissection, the conventional Pecs II is likely to produce superior analgesia and additionally may help achieve complete coverage of the deeper pectoral nerve branches.

Postoperative pain treatment with erector spinae plane block and pectoralis nerve blocks in patients undergoing mitral/tricuspid valve repair - a randomized controlled trial.

BACKGROUND: Effective postoperative pain control remains a challenge for patients undergoing cardiac surgery. Novel regional blocks may improve pain management for such patients and can shorten their length of stay in the hospital. To compare postoperative pain intensity in patients undergoing cardiac surgery with either erector spinae plane (ESP) block or combined ESP and pectoralis nerve (PECS) blocks. METHODS: This was a prospective, randomized, controlled, double-blinded study done in a tertiary hospital. Thirty patients undergoing mitral/tricuspid valve repair via mini-thoracotomy were included. Patients were randomly allocated to one of two groups: ESP or PECS + ESP group (1:1 randomization). Patients in both groups received a single-shot, ultrasound-guided ESP block. Participants in PECS + ESP group received additional PECS blocks. Each patient had to be extubated within 2 h from the end of the surgery. Pain was treated via a patient-controlled analgesia (PCA) pump. The primary outcome was the total oxycodone consumption via PCA during the first postoperative day. The secondary outcomes included pain intensity measured on the visual analog scale (VAS), patient satisfaction, Prince Henry Hospital Pain Score (PHHPS), and spirometry. RESULTS: Patients in the PECS + ESP group used significantly less oxycodone than those in the ESP group: median 12 [interquartile range (IQR): 6-16] mg vs. 20 [IQR: 18-29] mg (p = 0.0004). Moreover, pain intensity was significantly lower in the PECS + ESP group at each of the five measurements during the first postoperative day. Patients in the PECS + ESP group were more satisfied with pain management. No difference was noticed between both groups in PHHPS and spirometry. CONCLUSIONS: The addition of PECS blocks to ESP reduced consumption of oxycodone via PCA, reduced pain intensity on the VAS, and increased patient satisfaction with pain management in patients undergoing mitral/tricuspid valve repair via mini-thoracotomy. TRIAL REGISTRATION: The study was registered on the 19th July 2018 (first posted) on the ClinicalTrials.gov identifier: NCT03592485.

The pecs anesthetic blockade: A correlation between magnetic resonance imaging, ultrasound imaging, reconstructed cross-sectional anatomy and cross-sectional histology.

The interfascial thoracic wall blockades Pecs I and Pecs II are increasingly applied in breast and axillary surgery. Despite the clear anatomical demarcations depicted at their introduction, the clinical outcome is more variable than would be expected based upon the described anatomy. In order to elucidate factors that explain this variability, we evaluated the spread of each injection-medial Pecs I, lateral Pecs I, the deep injection of the Pecs II-separately. A correlation of in vivo landmarks and ultrasound images with ex vivo ultrasound, reconstructed anatomical planes, histology and magnetic resonance imaging. The medial Pecs I, similar to the sagittal infraclavicular block positioning with needle position medial to the pectoral branch of the thoracoacromial artery, reaches the medial and lateral pectoral nerves. The lateral Pecs I, below the lateral third of the clavicle at the level of the third rib with needle position lateral to the pectoral branch of the thoracoacromial artery, additionally spreads to the axilla and reaches the intercostobrachial nerve. The deep Pecs II injection spreads to the lateral cutaneous part of the III-VI intercostal nerves and reaches the long thoracic nerve. The variability of the Pecs anesthetic blockades is driven by the selected Pecs I approach as only the lateral approach stains the intercostobrachial nerve. The pectoral branch of the thoracoacromial artery can serve as the landmark to differentiate the needle position of the medial and lateral Pecs I block. Clin. Anat. 32:421-429, 2019. © 2019 Wiley Periodicals, Inc.

Anatomical versus functional motor points of selected upper body muscles.

INTRODUCTION: In this study we aimed to identify nerve entry points (NEPs) of superficial skeletal muscles obtained by dissection of 20 human cadavers and compared them with motor points (MP) obtained previously by electrical stimulation. METHODS: The biceps brachii (BB), trapezius (TZ), latissimus dorsi (LD), pectoralis major (Pmaj), and pectoralis minor (Pmin) muscles were dissected from human cadavers. NEP data (mean ± standard deviation) from each muscle were calculated. F-tests with Bonferroni corrections were used to compare NEPs and MPs. RESULTS: The number of NEPs was 2 in BB, 1 in Pmin, 4 in TZ, and 3 in LD, whereas the total number in Pmaj varied from 3 to 5. NEPs and MPs were statistically equal only in Pmin and in the descending part of TZ. DISCUSSION: The findings show crucial differences between NEPs and MPs, possibly impacting the effectiveness of several medical treatment strategies. Muscle Nerve 57: 460-465, 2018.

Pectoral nerves I block is associated with a significant motor blockade with no dermatomal sensory changes: a prospective volunteer randomized-controlled double-blind study.

PURPOSE: The pectoral nerves (PECS) I block, first described in 2011 for surgery involving the pectoralis muscle, has principally been used for breast cancer surgery. No formal evaluation of its differential motor- and sensory-blocking abilities has been reported. We hypothesize that the PECS I block will produce a motor block of the pectoralis muscles with diminished upper limb adduction strength as measured with a handheld dynamometer. METHODS: We conducted a PECS I block in a randomized placebo-controlled trial in six healthy subjects who received 0.4 mL·kg-1 of 0.9% saline (placebo) on one side and bupivacaine (0.25% with 1:400 000 epinephrine) on the other. We measured both upper limb adduction strength with a dynamometer and sensory skin levels over the thorax. RESULTS: The mean (standard deviation [SD]) adductor strength evaluated before the block was 119.4 (20.7) Newtons (N). After the PECS I block with bupivacaine, the mean (SD) strength of 54.2 (16.3) N was compared with 116.0 (30.4) N in the placebo group (difference in means 61.8 N; 95% confidence interval [CI], 27.8 to 95.8 N; P = 0.005), showing a 54.6% (95% CI, 43.6 to 65.6%) reduction in adductor strength. There was no difference in dermatomal skin sensory testing between the placebo and bupivacaine sides. CONCLUSIONS: This study shows that a PECS I block produces motor blockade as shown by reduced upper limb adductor strength without any overlying dermatomal sensory loss. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT03040167) 2 February 2017.

Treatment of Breast Animation Deformity in Implant-Based Reconstruction with Selective Nerve Ablation.

Breast animation deformity is a known complication of subpectoral implant placement that is usually corrected by repositioning the implant to the prepectoral position. Other less common treatment options include performing the muscle splitting biplanar technique, triple plane technique, neuromodulator injections, and secondary neurotomies via transection of the pectoral muscle. We report a patient with animation deformity successfully treated with direct identification and ablation of the medial and lateral pectoral nerves using selective bipolar electrocautery. The patient is a woman with a history of invasive ductal carcinoma who underwent bilateral mastectomy and breast reconstruction with subpectoral implant placement and autologous fat grafting. Within 1 year of her breast reconstruction, she developed hyperactive pectoralis muscle contraction with resulting distortion of both breasts. Given the disadvantages of repositioning the implant to the prepectoral position and transecting the pectoralis muscles via secondary neurotomy, we chose to directly identify and selectively ablate distal branches of the medial and lateral pectoral nerves. This offers a novel technique for correcting breast animation deformity without transecting the pectoralis muscles, causing muscle atrophy, and preserving the subpectoral implant position.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the table of contents or the online instructions to authors www.springer.com/00266 .

From Bedside to Bench: The Effect of Muscular Denervation on Fat Grafting to the Breast by Comparing Take Rate, Quality, and Longevity.

BACKGROUND: Autologous fat grafting (AFG) to the breast is a frequent procedure in aesthetic and reconstructive surgery. Despite pure volume gain, questions remain regarding the engraftment rate, quality, and longevity. Little is known about the role of recipient tissue or innervation of the grafted area. OBJECTIVES: The goal of this study was to determine the optimal recipient layer and muscular pretreatment of AFG. METHODS: Fat was grafted to the breast, pectoralis muscle, or adjacent subcutaneous tissue of 42 rats. Nerve treatment included excision of a nerve segment, botulinum toxin (BTX) injection, or no treatment. Magnetic resonance imaging (MRI) and histological workup were carried out after 2 and 6 weeks. RESULTS: Six weeks after AFG, the proportion of viable fat cells within the grafted fat stayed high (median, [IQR]: 81% [72% to 85%]). The signs of inflammation decreased over time. Intramuscular grafting with intact nerves had a decreasing effect on the viability of the grafted cells compared with subcutaneous treatment (-10.21%; 95% confidence interval [-21.1 to 0.68]). CONCLUSIONS: If utilized on an intact nerve, intramuscular injection may lead to inferior results. If the nerve was cut or treated with BTX; however, intramuscular injection tends to be superior. These findings may prove interesting for future studies and eventual clinical application.

Motor Nerve Preservation and Muscle Atrophy After Pectoralis Major Musculocutaneous Flap Surgery for Oromandibular Reconstruction.

OBJECTIVE: The authors investigated the clinical and histopathologic significance of medial pectoral nerve preservation/reinnervation of pectoralis major musculocutaneous flap for oromandibular reconstruction. MATERIALS AND METHODS: The authors compared 13 patients treated with pectoralis major musculocutaneous flap reconstruction and 6 control patients treated by rectus abdominis musculocutaneous flap reconstruction without motor nerve restoration. Subjective awareness was scored to evaluate changes in the facial contour due to muscle atrophy, and objective evaluation was performed in few patients. In addition, the authors performed histopathologic analysis of both muscle atrophy and nerve regeneration in 20 patients from whom samples were available. RESULTS: Subjective awareness of changes in the facial contour induced by muscle atrophy was low among patients with nerve preservation/reinnervation, but there were objective changes at 3 months after surgery among patients who underwent nerve resection. In the patients who had medial pectoral nerve preservation or nerve restoration by nerve suture, favorable facial symmetry was retained at 5 years after surgery. Even though the motor nerve was preserved or restored, fatty degeneration and fibrosis were noted in approximately 30% of the total surface area of the muscle, and type I fibers had decreased to 36% that of control at 7 years after surgery. However, regressive changes were inhibited for 1 year after surgery; in contrast, changes corresponding to those noted at 7 years after surgery were observed by 3 months in the patients with nerve resection. CONCLUSION: Thus, the authors showed that preservation or restoration of nerves can delay muscle and have highlighted the potential benefits of this approach.

An Anatomic Appraisal of Biplanar Muscle-Splitting Breast Augmentation.

BACKGROUND: Biplanar muscle-splitting (BMS) breast augmentation is a relatively new technique for which the safe regions of dissection have not been delineated. OBJECTIVES: The authors performed cadaver dissections to elucidate the surgical anatomy of the BMS pocket and to infer the safety of this method. METHODS: The breasts and chest regions of 5 female cadavers were dissected to identify anatomic landmarks and to ascertain the optimal split site in the pectoralis major. CS was defined as the lateral junction of the middle and caudal one-third of the sternum, and the sternal index was defined as the ratio of the length of the sternum to the distance from CS to the most medial major nerve branch. RESULTS: Initiating the muscle split at CS is likely to avoid nerve injury. The mean distance from CS to the most medial nerve branch was 15.36 cm. The sternal index is a reproducible marker of the extension of the nerve branches in relation to chest size. The sternal length and the cranio-caudal length of the pectoralis major were similar, enabling reliable planning of the muscle split site. CONCLUSIONS: If dissection is limited to the safe regions delineated herein, BMS breast augmentation is likely to be a safe procedure for most patients. By maintaining the connections between the pectoralis major and its origins, a breast deformity associated with muscle contraction may be avoidable.

Lateral Pectoral Nerve Injury Mimicking Cervical Radiculopathy.

The lateral pectoral nerve (LPN) is commonly injured along with the brachial plexus, but its isolated lesions are rare. Here, we present a case of an isolated LPN lesion confused with cervical radiculopathy. A 41-year-old man was admitted to our clinic because of weakness in his right arm. Previous magnetic resonance imaging (MRI) examination revealed right posterolateral protrusion at the C6-7 level. At the initial assessment, atrophy of the right pectoralis major muscle was evident, and mild weakness of the right shoulder adductor, internal rotator, and flexor muscles was observed. Therefore, electrodiagnostic evaluation was performed, and a diagnosis of isolated LPN injury was made. Nerve injury was thought to have been caused by weightlifting exercises and traction injury. Lateral pectoral nerve injury can mimic cervical radiculopathy, and MRI examination alone may lead to misdiagnosis. Repeated physical examinations during the evaluation and treatment phase will identify the muscle atrophy that occurs 1 or more months after the injury.

A comprehensive analysis of pectoralis major transfer for long thoracic nerve palsy.

BACKGROUND: In the treatment of long thoracic nerve palsy with pectoralis major transfer, it remains unknown whether direct transfer of the pectoralis to the scapula or indirect transfer with an interpositional graft provides superior outcomes. METHODS: A 3-tiered study was performed to gain a comprehensive understanding. (1) A survey of the membership of the American Shoulder and Elbow Surgeons (ASES) was conducted to reach a Level V consensus. (2) A systematic review was conducted to identify all series evaluating direct and indirect transfer of the pectoralis major tendon to create a Level IV consensus. (3) A retrospective review was performed to provide Level III evidence. RESULTS: (1) Surgeons were evenly split between whole and split tendon transfers, direct and indirect transfers, and graft types. More experienced surgeons were more likely to prefer an indirect transfer. (2) Analysis of 10 Level IV studies (131 shoulders) revealed that patients who underwent indirect transfer were significantly more likely to develop recurrent winging (P = .009) and had lower active forward elevation (P < .001) and ASES scores (P = .0016). (3) Twenty-four patients were included in our retrospective review with a mean follow-up of 4.3 years (77% follow-up), of whom 14 underwent indirect transfer and 10 underwent direct transfer. There were no significant differences in recurrence of winging, range of motion, or ASES scores. CONCLUSIONS: Level V and III evidence suggests that there is no functional difference between direct and indirect transfer. Level IV evidence must be interpreted with caution.

Neurovascular distribution within the abdominal head of the pectoralis major muscle: Application to breast and flap surgery.

The abdominal head of the pectoralis major (AHPM) is important in cosmetic and flap surgeries. Few studies have reported on its neurovascular entry points and distribution patterns. We aimed to determine the entry points and distribution patterns of the neurovascular structures within the AHPM. Thirty-two hemithoraxes were dissected, and the distribution patterns of the neurovascular structures were classified into several categories. The neurovascular entry points were measured at the horizontal line passing through the jugular notch (x-axis) and the midclavicular line (y-axis). The AHPM was innervated by the communication branches of the medial pectoral nerve (MPN) and the lateral pectoral nerve (LPN) in 78.1% of the specimens and of the MPN without the communication branches in 21.9%. All the LPNs had communication branches, which could be classified as independent in 46.9% of the samples, with the MPN in 21.9%, and with the LPN in 9.3%. The blood supply of the AHPM was composed of branches from the lateral thoracic artery (LTA) in 62.5% of the specimens, the thoracoacromial artery (TA) in 15.6%, and the LTA with the TA in 21.9%. The mean distance of the entry point was 6.3 cm ± 1.3 cm lateral to the y-axis, 8.1 cm ± 3.3 cm below the x-axis in the nerves, 6.5 cm ± 1.2 cm lateral to the y-axis, and 8.6 cm ± 3.0 cm below the x-axis in the arteries. This study defined the average neurovascular entry point and distribution pattern in detail using standard lines to enable the AHPM to be better understood.

Intraoperative ultrasound-guided pectoral nerve blocks for cardiac implantable device procedures.

BACKGROUND: Pectoral nerve (PECs) blocks are established regional anesthesia techniques that can provide analgesia to the anterior chest wall. Although commonly performed preoperatively by anesthesiologists, the feasibility of electrophysiologist-performed PECs blocks from within cardiac implantable electronic device (CIED) pockets at the time of implantation has not been established. The objective of this study is to assess the feasibility of routine PECs blocks performed by the electrophysiologist from within the exposed device pocket at the time of CIED procedures. METHODS: Patients undergoing CIED procedures underwent a PECs I block (15 cc of 1% lidocaine/0.25% bupivacaine) injected between the pectoralis major and minor muscles guided by ultrasound placed in the device pocket, or PECs II block, which included a second injection (15 cc) between pectoralis minor and serratus anterior muscles. Postoperatively, pain was assessed on a numeric scale (0-10) at 1, 2, 4, and 24 h, and 2 weeks after the procedure. RESULTS: Among 20 patients (age 65 ± 16 years, 70% male, 55% with history of chronic pain), PECs I (75%) and PECs II (25%) blocks were performed. The procedures were de novo implantation (n = 17) or device revision (n = 3). The average pain score in the first 4 h was 0.4 ± 0.8 and 0.3 ± 0.6 at 24 h after the procedure. During the 24-h postoperative period, 4 patients received opioids. Two patients were discharged with opioids for pain unrelated to the procedure. CONCLUSIONS: Intraoperative PECs blocks can be feasibly performed from within an exposed pocket at the time of CIED procedures with minimal postoperative pain.

Combined pectoralis and serratus anterior plane blocks with or without liposomal bupivacaine for minimally invasive thoracic surgery: A randomized clinical trial.

BACKGROUND: Minimally invasive thoracic surgery is associated with substantial pain that can impair pulmonary function. Fascial plane blocks may offer a favorable alternative to opioids, but conventional local anesthetics provide a limited duration of analgesia. We therefore tested the primary hypothesis that a mixture of liposomal bupivacaine and plain bupivacaine improves the overall benefit of analgesia score (OBAS) during the first three postoperative days compared to bupivacaine alone. Secondarily, we tested the hypotheses that liposomal bupivacaine improves respiratory mechanics, and decreases opioid consumption. METHODS: Adults scheduled for robotically or video-assisted thoracic surgery with combined ultrasound-guided pectoralis II and serratus anterior plane block were randomized to bupivacaine or bupivacaine combined with liposomal bupivacaine. OBAS was measured on postoperative days 1-3 and was analyzed with a linear mixed regression model. Postoperative respiratory mechanics were estimated using a linear mixed model. Total opioid consumption was estimated with a simple linear regression model. RESULTS: We analyzed 189 patients, of whom 95 were randomized to the treatment group and 94 to the control group. There was no significant treatment effect on total OBAS during the initial three postoperative days, with an estimated geometric mean ratio of 0.93 (95% CI: 0.76, 1.14; p = 0.485). There was no observed treatment effect on respiratory mechanics, total opioid consumption, or pain scores. Average pain scores were low in both groups. CONCLUSIONS: Liposomal bupivacaine did not improve OBAS during the initial postoperative three days following minimally invasive thoracic procedures. Furthermore, there was no improvement in respiratory mechanics, no reduction in opioid consumption, and no decrease in pain scores. Thus, the data presented here does not support the use of liposomal bupivacaine over standard bupivacaine to enhance analgesia after minimally invasive thoracic surgery. SUMMARY STATEMENT: For minimally invasive thoracic procedures, addition of liposomal bupivacaine to plain bupivacaine for thoracic fascial plane blocks does not improve OBAS, reduce opioid requirements, improve postoperative respiratory mechanics, or decrease pain scores.

Neuromuscular control of hovering wingbeat kinematics in response to distinct flight challenges in the ruby-throated hummingbird, Archilochus colubris.

While producing one of the highest sustained mass-specific power outputs of any vertebrate, hovering hummingbirds must also precisely modulate the activity of their primary flight muscles to vary wingbeat kinematics and modulate lift production. Although recent studies have begun to explore how pectoralis (the primary downstroke muscle) neuromuscular activation and wingbeat kinematics are linked in hummingbirds, it is unclear whether different species modulate these features in similar ways, or consistently in response to distinct flight challenges. In addition, little is known about how the antagonist, the supracoracoideus, is modulated to power the symmetrical hovering upstroke. We obtained simultaneous recordings of wingbeat kinematics and electromyograms from the pectoralis and supracoracoideus in ruby-throated hummingbirds (Archilochus colubris) hovering under the following conditions: (1) ambient air, (2) air density reduction trials, (3) submaximal load-lifting trials and (4) maximal load-lifting trials. Increased power output was achieved through increased stroke amplitude during air density reduction and load-lifting trials, but wingbeat frequency only increased at low air densities. Overall, relative electromyographic (EMG) intensity was the best predictor of stroke amplitude and is correlated with angular velocity of the wingtip. The relationship between muscle activation intensity and kinematics was independent of treatment type, indicating that reduced drag on the wings in hypodense air did not lead to high wingtip angular velocities independently of increased muscle work. EMG bursts consistently began and ended before muscle shortening under all conditions. During all sustained hovering, spike number per burst consistently averaged 1.2 in the pectoralis and 2.0 in the supracoracoideus. The number of spikes increased to 2.5-3 in both muscles during maximal load-lifting trials. Despite the relative kinematic symmetry of the hovering downstroke and upstroke, the supracoracoideus was activated ~1 ms earlier, EMG bursts were longer (~0.9 ms) and they exhibited 1.6 times as many spikes per burst. We hypothesize that earlier and more sustained activation of the supracoracoideus fibres is necessary to offset the greater compliance resulting from the presence of the supracoracoid tendon.

Pectoralis major transfer for subscapular deficiency: anatomical study of the relationship between the transferred muscle and the musculocutaneous nerve.

PURPOSE: Pectoralis major transfer is indicated for irreparable subscapularis tendon tears. One surgical option is transferring the sternal part of the pectoralis major to the humeral insertion of the subscapularis under the conjoined tendon of the coracobrachialis and biceps muscles. The purpose of this study is to define the anatomical relationship between the transferred tendon and the musculocutaneous nerve. METHODS: In 52 cadaveric fresh-frozen shoulders, the relevant structures were dissected and a pectoralis major transfer was performed. The relationship between the transferred tendon, the musculocutaneous nerve branches distally and the coracoid process proximally was examined. Measurements were taken at the conjoined tendon level. RESULTS: The distance between the coracoid process and the most proximal musculocutaneous nerve branch was 54.2 ± 33.2 mm. In 25 cases (48%), the transferred tendon passed freely between both structures. In 16 cases (31%), there was contact distally with the musculocutaneous nerve. In 11 cases (21%), there was contact both proximally with the coracoid process and distally with the musculocutaneous nerve, making a safe transfer impossible. CONCLUSIONS: When performing a pectoralis major transfer, it is essential to identify the musculocutaneous nerve and its branches. In some cases, a subcoracobicipital transfer may not be feasible and a more superficial transfer should be considered.

Selective ultrasound guided pectoral nerve targeting in breast augmentation: How to spare the brachial plexus cords?

Subpectoral breast augmentation surgery under regional anesthesia requires the selective neural blockade of the medial and lateral pectoral nerves to diminish postoperative pain syndromes. The purpose of this cadaver study is to demonstrate a reliable ultrasound guided approach to selectively target the pectoral nerves and their branches while sparing the brachial plexus cords. After evaluating the position and appearance of the pectoral nerves in 25 cadavers (50 sides), a portable ultrasound machine was used to guide the injection of 10 ml of 0.2% aqueous methylene blue solution in the pectoral region on both sides of three Thiel's embalmed cadavers using a single entry point-triple injection technique. This technique uses a medial to lateral approach with the entry point just medial to the pectoral minor muscle and three subsequent infiltrations: (1) deep lateral part of the pectoralis minor muscle, (2) between the pectoralis minor and major muscles, and (3) between the pectoralis major muscle and its posterior fascia under ultrasound visualization. Dissection demonstrates that the medial and lateral pectoral nerves were well stained while leaving the brachial plexus cords unstained. We show that 10 ml of an injected solution is sufficient to stain all the medial and lateral pectoral nerve branches without a proximal extension to the cords of the brachial plexus.

Ideal Injection Points for Botulinum Neurotoxin for Pectoralis Minor Syndrome: A Cadaveric Study.

Pectoralis Minor Syndrome (PMS) causes significant discomfort due to the compression of the neurovascular bundle within the retropectoralis minor space. Botulinum neurotoxin (BoNT) injections have emerged as a potential treatment method; however, their effectiveness depends on accurately locating the injection site. In this study, we aimed to identify optimal BoNT injection sites for PMS treatment. We used twenty-nine embalmed and eight non-embalmed human cadavers to determine the origin and intramuscular arborization of the pectoralis minor muscle (Pm) via manual dissection and Sihler's nerve staining techniques. Our findings showed the Pm's origin near an oblique line through the suprasternal notch, with most neural arborization within the proximal three-fourths of the Pm. Blind dye injections validated these results, effectively targeting the primary neural arborized area of the Pm at the oblique line's intersection with the second and third ribs. We propose BoNT injections at the arborized region within the Pm's proximal three-fourths, or the C region, for PMS treatment. These findings guide clinicians towards safer, more effective BoNT injections.

Novel Diagnostic and Treatment Techniques for Neurogenic Thoracic Outlet Syndrome.

Neurogenic thoracic outlet syndrome is a challenging condition to diagnose and treat, often precipitated by the triad of repetitive overhead activity, pectoralis minor contracture, and scapular dyskinesia. The resultant protracted scapular posture creates gradual repetitive traction injury of the suprascapular nerve via tethering at the suprascapular notch and decreases the volume of the brachial plexus cords and axillary vessels in the retropectoralis minor space. A stepwise and exhaustive diagnostic protocol is essential to exclude alternate pathologies and confirm the diagnosis of this dynamic pathologic process. Ultrasound-guided injections of local anesthetic or botulinum toxin are a key factor in confirming the diagnosis and prognosticating potential response from surgical release. In patients who fail over 6 months of supervised physical therapy aimed at correcting scapular posture and stretching of the pectoralis minor, arthroscopic surgical release is indicated. We present our diagnostic algorithm and technique for arthroscopic suprascapular neurolysis, pectoralis minor release, brachial plexus neurolysis, and infraclavicular thoracic outlet decompression.