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.

Extramuscular and Intramuscular Course of the Nerve Innervating the Abdominal Part of the Pectoralis Major Muscle: An Anatomical Study with Regard to Transaxillary Endoscopic Subpectoral Breast Augmentation.

BACKGROUND: During transaxillary endoscopic subpectoral breast augmentation, the innervation of the abdominal part of the pectoralis major muscle can be injured. The question has been raised whether this could even be of value, as for a better result, the caudal fibers of the pectoralis major muscle have to be detached from their origin. The authors' aim was to identify the exact position and the intramuscular course and target of these nerve branches. METHODS: Fifty pectoralis major muscles and their supplying nerve branches from 27 formalin-fixed anatomical specimens were studied using macroscopic dissection and anthropometry. Furthermore, eight muscles underwent the modified Sihler procedure to determine the intramuscular course and target of the supplying nerve branches. RESULTS: The branches for the abdominal part of the pectoralis major muscle pierced the pectoralis minor muscle or coursed around its lower border 3.2 to 8.4 cm from the tip of the coracoid process. Within the muscle, at least one small nerve branch, innervating the abdominal part, ascended into the lowermost portion of the sternocostal head, and anastomosed with the lowest small branch of its supplying nerve branches. CONCLUSIONS: Because of the variable position of the nerve branches, they may often cross the operative field during transaxillary endoscopic breast augmentation. However, their interruption can be of value, because weakening of the lower part of the pectoralis major muscle is desired to keep the implant in place, and to avoid animation deformity.

Transfer of a C7 Fascicle for the Pectoralis Major to the Suprascapular Nerve: A 3-Year Follow-Up Patient Series.

BACKGROUND: In patients with C5-C6 brachial plexus injury, spinal accessory nerve transfer to the suprascapular nerve is usually performed for the restoration of shoulder abduction. In order to minimize donor deficits, we transferred one fascicle of the ipsilateral C7 root, dedicated to the pectoralis major muscle, to the suprascapular nerve. METHODS: Ten patients with a mean age of 33 years (range, 19 to 51 years) were operated on at a mean delay of 4 months after their trauma (range, 2 to 7 months). Patients had C5-C6 brachial plexus palsy with avulsed roots on spinal magnetic resonance imaging scan. In addition to the partial C7 transfer, patients sustained nerve transfers to the posterior branch of the axillary nerve and to the motor branches of the musculocutaneous nerve for the biceps and brachialis muscles. RESULTS: At a mean follow-up of 36 months (range, 29 to 42 months), mean shoulder abduction and external rotation ranges of motion were, respectively, 99 degrees (range, 60 to 120 degrees; p = 0.001) and 58 degrees (range, 0 to 80 degrees; p = 0.001). In nine patients, shoulder abduction strength was graded M4, according the British Medical Research Council grading scale, against 1.6 kg (range, 1 to 2 kg), and was graded M3 in one patient. External rotation strength was graded M4 in nine patients and M3 in one patient. Residual strength of the pectoralis major muscle was graded M4+ in every patient. CONCLUSIONS: C7 partial transfer to the suprascapular nerve showed satisfactory results at long-term follow-up for active shoulder abduction and external rotation recovery in C5-C6 brachial plexus palsies. This technique replaced spinal accessory nerve transfer in the authors' practice. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Selective Denervation of Pectoralis Major Muscle Improves Cosmetic Outcome and Quality of Life in Retro-Pectoral Implant Based Breast Reconstruction.

BACKGROUND: Selective pectoralis major muscle (PMM) denervation has been described in retro-pectoral reconstructions to obtain the advantages of the pre-pectoral approach. Present study compared subjective evaluations between retro-pectoral implant based breast reconstructions (IBBRs) with denervation to traditional techniques without denervation. METHODS: In 2020, two 2 groups of patients submitted to retro-pectoral IBBR, minimum 12-month follow-up, were compared through BREAST-Q post-operative questionnaire. Group-1 included direct-to-implant or two2-stage tissue expanderTE cases with selective PMM denervation, while Group-2 similar procedures, in the same time span 2017-2019, without denervation. BREAST-Q was divided into five 5 independent scales and for each scale item responses were summed up and transformed into a score, ranging from 0 to 100, to analyze and compare the results. RESULTS: 50 patients were included both in Group1 and Group-2. Group-1 patients reported significantly higher scores in "satisfaction with the reconstructed breast" scale compared to Group-2, means-medians of 56-58 and 47-50, respectively. A trend in favor of Group-1 was recorded in the scales of "psycho-social well-being", 64-65 vs. 58-53, and "sexual well-being", 53-47 vs. 48-47, albeit not significant. Substantial equivalence was found in "satisfaction with the result overall" and "physical well-being". CONCLUSION: PMM denervation can improve cosmetic results in retro-pec IBBRs, thus leading to better QoL. Possible pain and physical discomfort weren't caused by denervation with scores similar to non-denervated controls.

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.

Innervation of the clavicle: a cadaveric investigation.

BACKGROUND: This cadaveric study investigated the innervations of the clavicle and clavicular joints (ie, sternoclavicular and acromioclavicular joints). METHODS: Twenty cadavers (40 clavicles) were dissected. A skin incision was made to permit exposure of the posterior cervical triangle and infraclavicular fossa. The platysma, sternocleidomastoid, and trapezius muscles were cleaned in order to identify the supraclavicular nerves. Subsequently, the suprascapular and subclavian nerves were localized after removal of the prevertebral layer of the deep cervical fascia. In the infraclavicular region, the pectoralis major and minor muscles were retracted laterally in order to visualize the lateral pectoral nerve. The contribution of all these nerves to the clavicular bone and joints were recorded. RESULTS: Along their entire length, all clavicular specimens received contributions from the supraclavicular nerves. The latter innervated the cephalad and ventral aspects of the clavicular bone. The caudal and dorsal aspects of the clavicle were innervated by the subclavian nerve (middle and medial thirds). The lateral pectoral nerve supplied the caudad aspect of the clavicle (middle and lateral thirds). The sternoclavicular joint derived its innervation solely from the supraclavicular nerves whereas the acromioclavicular joint was supplied by the supraclavicular and lateral pectoral nerves. CONCLUSION: The clavicle and clavicular joints are innervated by the subclavian, lateral pectoral, and supraclavicular nerves. Clinical trials are required to determine the relative importance and functional contribution of each nerve.

Moving Toward Opioid-Free Breast Surgery: Regional Blocks and a Novel Technique.

Perioperative pain control is of increasing importance as awareness regarding the risks of under-controlled pain and opioid abuse rise. Enhanced recovery protocols and multimodal analgesia, including regional blocks, are useful tools for the plastic surgeon. The thoracic paravertebral block, pectoralis nerve I and pectoralis nerve II blocks, and proximal intercostal blocks are 3 described methods that provide regional anesthesia for breast surgery. The widespread use of these methods may be limited by the requirements for ultrasound equipment and anesthesiologists skilled in regional blocks. This article describes a novel technique of the intercostal field block under direct visualization that is safe and efficient.

Evaluation of postoperative pain in patients undergoing modified radical mastectomy with pectoralis or serratus-intercostal fascial plane blocks.

BACKGROUND: Regional nerve blocks are an integral part of multimodal analgesia and should be chosen based on their efficacy, convenience, and minimal side effects. Here, we compare the use of pectoral (PEC II) and serratus-intercostal fascial plane (SIFP) blocks in breast carcinoma cases undergoing modified radical mastectomy (MRM) in terms of the postoperative analgesic efficacy and shoulder mobility. METHODS: The primary outcome of this prospective controlled study was to compare the postoperative static and dynamic pain scores, and the secondary outcome was to assess the shoulder pain, range of shoulder joint motion, and hemodynamic parameters. Sixty patients were randomly allocated to three groups and given general anesthesia. All patients received paracetamol, diclofenac, and rescue doses of tramadol based on the Institute's Acute Pain Service (APS) policy. No block was performed in group C (control), whereas groups P and S received PEC II and SIFP blocks, respectively, before surgical incision. RESULTS: The groups were comparable in terms of age, weight, height, and body mass index distribution (P > 0.05). Dynamic pain relief was significantly better 12 and 24 h postoperatively in groups P (P = 0.034 and P = 0.04, respectively) and S (P = 0.01 and P = 0.02, respectively) compared to group C. Shoulder pain relief and shoulder mobility were better in group S, while the hemodynamic parameters were more stable in group P. CONCLUSIONS: Both SIFP and PEC blocks have comparable dynamic and static pain relief with better shoulder pain scores in patients receiving SIFP.

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.

Anatomical Variations of the Pectoralis Major Muscle: Notes on Their Impact on Pectoral Nerve Innervation Patterns and Discussion on Their Clinical Relevance.

BACKGROUND: The presented study attempts to classify individual anatomical variants of the pectoralis major muscle (PM), including rare and unusual findings. Rare cases of muscular anomalies involving the PM or its tendon have been presented. An attempt has also been made to determine whether anatomical variations of the PM may affect the innervation pattern of the lateral and medial pectoral nerves. MATERIAL AND METHODS: The research was carried out on 40 cadavers of both sexes (22 males, 18 females), owing to which 80 PM specimens were examined. RESULTS: Typical PM structure was observed in 63.75% of specimens. The most frequently observed variation was a separate clavicular portion of the PM. In one female cadaver (2.5% of specimens) the hypotrophy of the clavicular portion of the PM was noticed. In two male cadavers (5% of specimens) the fusion between the clavicular portion of the PM and the deltoid muscle was observed. In one of those cadavers, small sub-branches of the lateral pectoral nerve bilaterally joined the clavicular portion of the deltoid muscle. The detailed intramuscular distribution of certain nerve sub-branches was visualized by Sihler's stain. PM is mainly innervated by the lateral pectoral nerve. In all specimens stained by Sihler's technique, the contribution of the intercostal nerves in PM innervation was confirmed. CONCLUSIONS: Surgeons should be aware of anatomic variations of the PM both in planning and in conducting surgeries of the pectoral region.

Analgesic efficacy of modified pectoral block plus serratus plane block in breast augmentation surgery: A randomised, controlled, triple-blind clinical trial. / Eficacia analgésica del bloqueo pectoral modificado más bloqueo del plano del serrato en mamoplastia subpectoral: ensayo clínico, controlado, aleatorizado, triple ciego.

INTRODUCTION: Prosthetic breast surgery is a very common plastic surgery procedure, but its postoperative analgesic management is a challenge for the surgical team. The purpose of the present study is to validate the analgesic efficacy of pectoral block and serratus plane block in retropectoral mammoplasty. PATIENTS AND METHODS: A randomised, controlled, triple-blind, clinical trial was designed, and included 30 patients undergoing retropectoral augmentation mammoplasty. All of them had a modified PECII block and a serratus plane block with a total volume of 40ml per breast. In 15 of them bupivacaine 0.25% (GPEC) was injected and in the other 15 patients saline was used (GC). Standardised management of anaesthesia and postoperative analgesia was performed. Intra-operative haemodynamic parameters required for postoperative analgesia, and a numeric verbal scale on arrival in the recovery unit were measured and at 3, 6, and 24h. The quality perceived by patients and surgeons was also measured. RESULTS: Post-operative pain was significantly better in GPEC (5.3±2.3 vs. 2.9±2.7; P=.018). No significant differences were observed at 3, 6, and 24h. The surgeons rated the anaesthetic-analgesic quality as very good in 80% of the cases in GPEC versus 33% in CG (P=.01). CONCLUSIONS: The use of these blocks is a good perioperative analgesic strategy in the multimodal management of retropectoral augmentation mammoplasty.

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.

The effect of lateral pectoral nerve sparing technique and radiotherapy on the pectoralis major muscle applied with modified radical mastectomy.

BACKGROUND/OBJECTIVE: The aim of this study was to evaluate with electromyography (EMG) the effect of lateral pectoral nerve sparing technique (LPNST) and radiotherapy (RT) on the lateral pectoral nerve (LPN) in patients applied with modified radical mastectomy (MRM). METHODS: The study included 66 patients who underwent MRM surgery. The patients were separated into 2 groups as those applied with LPNST and those who underwent standard surgery (Control group). Within these 2 groups, patients were again separated as those who received or did not receive RT. The EMG evaluations were made by a neurology specialist blinded to the patient groups. RESULTS: The mean age of the patients was 53.3 ± 10.6 years. Standard surgery was applied to 33 (50%) patients and LPNST to 33 (50%) patients, RT was applied to 32 (48.5%) patients and not to 34 (51.5%) patients. In the EMG evaluation, latency was 2.1 ms (1.4-3.2) in the LPNST and 3.7 ms (1.9-12.4) in the control (p <0.001) and amplitude values were 9650 mV (3120-36900) in the LPNST and 4780 mV (510-12.4) in the control (p <0.001). The latency values in the Control receiving and not receiving RT were 4.0 ms (1.9-12.4) and 2.6 ms (1.9-6.2) respectively (p <0.05). The latency values of the patients receiving and not receiving RT in the LPNST were 2.2 ms (1.8-3.2) and 2.0 ms (1.4-2.4) respectively (p <0.05). In the Control and LPNST Group, no significant difference was determined between receiving and not receiving RT groups in respect of amplitude values (p >0.05). CONCLUSION: The results of this study demonstrated that electromyographically the latency and amplitude values were better protected in the LPNST group. It was also seen that RT increased the formation of nerve damage in both groups.