Distribution of the axillary nerve to the subacromial bursa and the area around the long head of the biceps tendon

Subpectoral, Suprapectoral, and Top-of-Groove Biceps Tenodesis Procedures Lead to Similar Good Clinical Outcomes: Comparison of Biceps Tenodesis Procedures

Purpose

To determine whether there is a difference in clinical results among open subpectoral (SB), arthroscopic low-in-groove suprapectoral (SP), and arthroscopic top-of-groove (TOG) locations in terms of patient-reported outcome measures for biceps tenodesis (BT) procedures using a global, self-reporting registry.

Methods

We identified patients who underwent BT surgery in the Surgical Outcomes System registry. The inclusion criteria were isolated primary surgical procedures for BT, excluding patients with rotator cuff and labral repairs. Additional search requirements included repair location and 100% compliance with pretreatment and 2-year follow-up surveys. This study measured clinical outcomes comparing the 3 aforementioned techniques using the American Shoulder and Elbow Surgeons (ASES) score, visual analog scale (VAS) pain score, and Single Assessment Numeric Evaluation (SANE) score before treatment and at 3 months, 6 months, 1 year, and 2 years postoperatively. In addition, postoperative VAS pain scores were collected at 2 and 6 weeks. Statistical analysis was conducted using analysis of variance (Kruskal-Wallis test) and the Wilcoxon test.

Results

A total of 1,923 patients from the Surgical Outcomes System registry qualified for the study; of these, 879 underwent the SB technique, 354 underwent the SP technique, and 690 underwent the TOG technique. There was no statistically significant difference in the demographic characteristics among the groups except that the TOG group was older: 60.76 years versus 54.56 years in the SB group and 54.90 years in the SP group (P < .001). In all groups, the ASES score statistically improved from before treatment (mean, 49.29 ± 0.63) to 2 years postoperatively (mean, 86.82 ± 0.80; P < .05). There were no statistically significant differences among the 3 groups in the VAS, ASES, and SANE scores at all time points (P > .12) except for the VAS score at 1 year (P = .032) and the ASES score at 3 months (P = .0159). At 1 year, the mean VAS score in the SB group versus the TOG group was 1.146 ± 1.27 versus 1.481 ± 1.62 (P = .032), but the minimal clinically important difference (MCID) was not met. The 3-month ASES Index scores in the SB, SP, and TOG groups were 68.991 ± 18.64, 66.499 ± 17.89, and 67.274 ± 16.9, respectively (P = .0159), and similarly, the MCID was not met. At 2 years, the ASES scores in the SB, SP, and TOG groups improved from 49.986 ± 18.68, 49.54 ± 16.86, and 49.697 ± 7.84, respectively, preoperatively to 86.00 ± 18.09, 87.60 ± 17.69, and 86.86 ± 16.36, respectively, postoperatively (P > .12).

Conclusions

The SB, SP, and TOG BT procedures each resulted in excellent clinical improvement based on patient-reported outcome measures from a global registry. On the basis of the MCID, no technique was clinically superior to the other techniques in terms of VAS, ASES, or SANE scores at any time point up to 2 years.

Level of Evidence

Level III, retrospective comparative study.

Clinical implications of the distinct anatomy and innervation of the long head biceps tendon

The proximal long head of the biceps tendon (LHBT) has been recognized as a well-known cause of anterior shoulder pain. Previous studies have identified a heterogeneous distribution of nerve fibers in the tendon, with a higher abundance of fibers in the proximal and distal thirds of the tendon. This suggests that the proximal portion of the long head biceps tendon may have a different source of innervation than the distal portion. The purpose of this study was to review the innervation of the superior shoulder and identify the proximal source of sensory innervation of the LHBT. The relevant hypothesis was that the suprascapular nerve (SSN) was the proximal source of sensory innervation to the LHBT. Gross and microdissection of eight fresh human cadaver shoulders were performed, with a focus on the distal articular branches of suprascapular nerve (SSN). Utilizing 3.5× magnification loupes, the medial subacromial branch (MSAb), lateral subacromial branch (LSAb), and posterior glenohumeral branch (PGHb) were identified and followed distally to their terminal branches. In all specimens, terminal branches of the lateral subacromial branch supplied the proximal LHBT and the superior labrum. Terminal branches of the posterior glenohumeral branch supplied the posterosuperior labrum and, to a lesser extent, the labral attachment of the LHBT. These findings confirm branches of the suprascapular nerve as the proximal source of sensory innervation to the LHBT. Identification of the suprascapular nerve as a source of proximal innervation of the LHBT may influence clinical decisions related to nonsurgical and surgical intervention, nerve blocks, and nerve ablation procedures.

Reliable Clinical and Sonographic Outcomes of Subpectoral Biceps Tenodesis Using an All-Suture Anchor Onlay Technique

PURPOSE

To evaluate the clinical outcomes and structural integrity of primary subpectoral biceps tenodesis using an all-suture anchor onlay technique for long head of the biceps (LHB) tendon pathology.

METHODS

We conducted a retrospective case series with prospectively collected data of patients who underwent primary, isolated subpectoral biceps tenodesis with a single all-suture anchor onlay fixation between March 2017 and March 2019. Outcomes were recorded at a minimum follow-up of 12 months based on assessments of the American Shoulder and Elbow Surgeons (ASES) score, LHB score, and elbow flexion strength and supination strength measurements. The integrity of the tenodesis construct was evaluated using ultrasound.

RESULTS

Thirty-four patients were available for clinical and ultrasound examination at a mean follow-up of 18 ± 5 months. The mean ASES score significantly improved from 51.0 ± 14.2 points preoperatively to 89.8 ± 10.5 points postoperatively (P < .001). The minimal clinically important difference for the ASES score was 8.7 points, which was exceeded by 31 patients (91.2%). The mean postoperative LHB score was 92.2 ± 8.3 points. Regarding subcategories, an average of 47.2 ± 6.3 points was reached for "pain/cramps"; 26.4 ± 6.1 points, "cosmesis"; and 18.6 ± 2.6 points, "elbow flexion strength." Both elbow flexion strength and supination strength were similar compared with the nonoperated side (P = .169 and P = .210, respectively). In 32 patients, ultrasound examination showed an intact tenodesis construct, whereas 2 patients (5.9%) sustained failure of the all-suture anchor fixation requiring revision.

CONCLUSIONS

Primary subpectoral biceps tenodesis using an all-suture anchor onlay technique for pathology of the LHB tendon provides reliable clinical results and a relatively low failure rate (5.9%).

LEVEL OF EVIDENCE

Level IV, case series.

Overview of Innervation of Shoulder and Acromioclavicular Joints

Detailed understanding of the course and location of articular nerves supplying the shoulder joint is paramount to the successful utilization of image-guided radiofrequency ablation to manage chronic shoulder pain. In this article, the origin, course, and relationship to anatomic landmarks of articular nerves supplying the shoulder and acromioclavicular joints are discussed. The shoulder joint capsule was consistently reported to receive innervation from multiple sources including the suprascapular, axillary, subscapular, and lateral pectoral nerves. The acromioclavicular joint received innervation from suprascapular and lateral pectoral nerves. The consistent relationship of articular branches to anatomic landmarks provides the basis for specific image-guided targeting.

Putting Our Shoulder to the Wheel: Current Understanding and Gaps in Nerve Ablation for Chronic Shoulder Pain

Shoulder pain is prevalent, burdensome, and functionally limiting, with diverse pathology and associated treatments. This narrative review provides a summary of relevant neuroanatomy, proposed ablation targets, safety and efficacy concerns for ablation targets, and current research gaps. Radiofrequency ablation (RFA) of peripheral sensory nerves is a well-established treatment for chronic joint and spine pain, but it is relatively nascent for shoulder pain. Cadaveric studies demonstrate the shoulder joint is innervated by articular branches of the suprascapular nerve, axillary nerve, lateral pectoral nerve, and upper and lower subscapular nerves. Shoulder articular branch RFA appears to be a safe and effective treatment for chronic shoulder pain, but there are currently no widely accepted protocols for ablation targets. There are also no randomized controlled trials (RCT) assessing safety and efficacy of proposed targets or the prognostic value of articular blocks. Future research studies should prioritize categorical data, use appropriate functional measures as primary endpoints, and would ideally include a large-scale RCT.

Cadaveric evaluation of the feasibility of glenohumeral joint denervation

Purpose

To assess the feasibility of total shoulder denervation through two proposed incisions.

Methods

Total shoulder denervation was performed through an extended delta-pectoral approach and a transverse dorsal approach at the spine of the scapula. The study involved six cadavers. Course and number of articular branches from the lateral pectoral, axillary and supra-scapular nerve were documented.

Results

All shoulder joint articular branches were accessible through the proposed anterior and posterior approaches. The articular branch of the lateral pectoral nerve and supra scapular nerve were present in all the specimen. Axillary nerve articular branches were variable in number but when present anteriorly were proximal to the deltoid muscular branches and posteriorly proximal to the muscular branches to the teres minor.

Conclusion

Total glenohumeral denervation was feasible through our proposed anterior and posterior approaches. Enhanced knowledge of articular nerve branches could provide interventional targets for joint and ligament pain, with low risk of muscle weakness.

Sensory innervation of the human shoulder joint: the three bridges to break

BACKGROUND

Painful shoulders create a substantial socioeconomic burden and significant diagnostic challenge for shoulder surgeons. Consensus with respect to the anatomic location of sensory nerve branches is lacking. The aim of this literature review was to establish consensus with respect to the anatomic features of the articular branches (ABs) (1) innervating the shoulder joint and (2) the distribution of sensory receptors about its capsule and bursae.

MATERIALS AND METHODS

Four electronic databases were queried, between January 1945 and June 2019. Thirty original articles providing a detailed description of the distribution of sensory receptors about the shoulder joint capsule (13) and its ABs (22) were reviewed.

RESULTS

The suprascapular, lateral pectoral, axillary, and lower subscapular nerves were found to provide ABs to the shoulder joint. The highest density of nociceptors was found in the subacromial bursa. The highest density of mechanoreceptors was identified within the insertion of the glenohumeral ligaments. The most frequently identified innervation pattern comprised 3 nerve bridges (consisting of ABs from suprascapular, axillary, and lateral pectoral nerves) connecting the trigger and the identified pain generator areas rich in nociceptors.

CONCLUSION

Current literature supports the presence of a common sensory innervation pattern for the human shoulder joint. Anatomic studies have demonstrated that the most common parent nerves supplying ABs to the shoulder joint are the suprascapular, lateral pectoral, and axillary nerves. Further studies are needed to assess both the safety and efficacy of selective denervation of the painful shoulders, while limiting the loss of proprioceptive function.

Clinical relevance of the anatomy of the long head bicipital groove, an evidence-based review

Pathology in the bicipital groove can be a source of anterior shoulder pain. Many studies have compared treatment techniques for the long head biceps tendon (LHBT) without showing any clinically significant differences. As the LHBT is closely related to the bicipital groove, anatomical aspects of this groove could also be implicated in surgical outcomes. The aim of this review is to contribute to developing the optimal surgical treatment of LHBT pathology based on clinically relevant aspects of the bicipital groove. Medline/PubMed was systematically searched using key words "bicipital" and "groove" and combinations of their synonyms. Studies reporting on evolution, embryonic development, morphometry, vascularization, innervation, and surgical treatment of the LHBT and the bicipital groove were included. The length of the bicipital groove reported in the included studies ranged from 81.00 mm to 87.33 mm, width from 7.74 mm to 11.60 mm, and depth from 3.70 mm to 6.00 mm. The anatomy of the bicipital groove shows a bottleneck narrowing approximately two-thirds from superior. The transverse humeral ligament can constrain the bicipital groove and could be involved in anterior shoulder pain. When either LHBT tenotomy or tenodesis is performed, routinely releasing the transverse ligament could decrease postoperative anterior shoulder pain, which has frequently been reported in the literature. To avoid the bottle neck narrowing, a location below the bicipital groove may be preferred for biceps tenodesis over a more proximal tenodesis site. Level of evidence: IV.

A randomized controlled trial evaluating the impact of selective axillary nerve block after arthroscopic subacromial decompression

BACKGROUND

The sensory innervation of the shoulder is complex and there are variations in the branching patterns of the sensory fibres. Articular branches from the axillary nerve to the subacromial bursa are described in more than 50% of investigated shoulders but the isolated contribution of sensory input from the axillary nerve has never been investigated clinically. We hypothesized that a selective block of the axillary nerve would reduce morphine consumption and pain after arthroscopic subacromial decompression.

METHODS

We included 60 patients in a randomized, blinded, placebo-controlled study. Patients were randomized to a preoperative selective ultrasound-guided axillary nerve block with 20 mL ropivacaine (7.5 mg/mL) or 20 mL saline. Primary outcome was intravenous morphine consumption 0-4 h postoperatively. Secondary outcome was postoperative pain evaluated by a visual analogue scale (VAS) score (0-100).

RESULTS

We analysed data from 50 patients and found no significant difference in 0-4 h postoperative morphine consumption between the two groups (ropivacaine 14 mg, placebo 18 mg (P = 0.12)). There was a reduction in postoperative pain: VAS 0-4 h (area under the curve) (ropivacaine 135, placebo 182 (P = 0.03)), VAS after 8 h (ropivacaine 9, placebo 20 (P = 0.01)) and VAS after 24 h (ropivacaine 7, placebo 18 (P = 0.04)). Eight out of 19 patients with a successful selective axillary nerve block needed an interscalene brachial plexus escape block.

CONCLUSIONS

Selective block of the axillary nerve has some pain relieving effect, but in this setting the effect was unpredictable, variable and far from sufficient in a large proportion of the patients.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01463865). Registered: November 1, 2011.

Quantitative analysis of the distal, lateral, and posterior articular branches of the axillary nerve to the shoulder: implications for intervention

INTRODUCTION

The terminal sensory branches innervating the shoulder joint are potential therapeutic targets for the treatment of shoulder pain. This cadaveric study investigated in detail the anatomic pathway of the posterior terminal sensory branch of the axillary nerve (AN) and its relationship to nearby anatomic structures for applications, such as nerve block or ablation of the shoulder joint.

METHODS

For this study, nine shoulders were dissected. Following dissection, methylene blue was used to stain the pathway of the terminal sensory branches of the AN to provide a visual relationship to the nearby bony structures. A transparent grid was overlaid on the humeral head to provide further detailed information regarding the innervation to the shoulder joint.

RESULTS

Eight of the nine shoulders displayed terminal sensory branches of the AN. The terminal sensory branches of the AN innervated the posterolateral head of the humerus and shoulder capsule and were deep and distal to the motor branches innervating the deltoid muscle and teres minor muscle. All terminal branches dissected innervated the shoulder capsule at the posteroinferior-lateral aspect of the greater tuberosity of the humerus. All specimens displayed innervation to the shoulder joint in the lateral most 25% and inferior most 37.5% before methylene blue staining.

CONCLUSION

The terminal sensory branches of the AN consistently innervate the inferior and lateral aspects of the posterior humeral head and shoulder capsule. These nerves are easily accessible and would provide a practical target for nerve block or ablation to relieve shoulder pain without compromising motor integrity.

Ultrasonography-guided anterior approach for axillary nerve blockade: An anatomical study

Combined ultrasound (US)-guided blockade of the suprascapular and axillary nerves (ANs) has been proposed as an alternative to interscalene blockade for pain control in shoulder joint pathology or postsurgical care. This technique could help avoid respiratory complications and/or almost total upper limb palsy. Nowadays, the AN blockade is mostly performed using an in-plane caudal-to-cephalic approach from the posterior surface of the shoulder, reaching the nerve immediately after it exits the neurovascular quadrangular space (part of the spatium axillare). Despite precluding most respiratory complications, this approach has not made postsurgical pain relief any better than an interscalene blockade, probably because articular branches of the AN are not blocked.Cephalic-to-caudal methylene blue injections were placed in the first segment of the AN of six Thiel-embalmed cadavers using an US-guided anterior approach in order to compare the distribution with that produced by a posterior approach to the contralateral AN in the same cadaver. Another 21 formalin-fixed cadavers were bilaterally dissected to identify the articular branches of the AN.We found a good spread of the dye on the AN and a constant relationship of this nerve with the subscapularis muscle. The dye reached the musculocutaneous nerve, which also contributes to shoulder joint innervation. We describe the anatomical landmarks for an ultrasonography-guided anterior AN blockade and hypothesize that this anterior approach will provide better pain control than the posterior approach owing to complete blocking of the joint nerve. Clin. Anat. 33:488-499, 2020. © 2019 Wiley Periodicals, Inc.

Anatomical study of the innervation of glenohumeral and acromioclavicular joint capsules: implications for image-guided intervention

BACKGROUND AND OBJECTIVES

In 2011, chronic shoulder joint pain was reported by 18.7 million Americans. Image-guided radiofrequency ablation has emerged as an alternative intervention to manage chronic shoulder joint pain. To optimize the effectiveness of shoulder denervation, it requires a detailed understanding of the nerve supply to the glenohumeral and acromioclavicular joints relative to landmarks visible with image guidance. The purpose of this cadaveric study was to determine the origin, course, relationships to bony landmarks, and frequency of articular branches innervating the glenohumeral and acromioclavicular joints.

METHODS

Fifteen cadaveric specimens were meticulously dissected. The origin, course, and termination of articular branches supplying the glenohumeral and acromioclavicular joints were documented. The frequency of each branch was determined and used to generate a frequency map that included their relationships to bony and soft tissue landmarks.

RESULTS

In all specimens, the posterosuperior quadrant of the glenohumeral joint was supplied by suprascapular nerve; posteroinferior by posterior division of axillary nerve; anterosuperior by superior nerve to subscapularis; and anteroinferior by main trunk of axillary nerve. Less frequent innervation was found from lateral pectoral nerve and posterior cord. The acromioclavicular joint was found to be innervated by the lateral pectoral and acromial branch of suprascapular nerves in all specimens. Bony and soft tissue landmarks were identified to localize each nerve.

CONCLUSIONS

The frequency map of the articular branches supplying the glenohumeral and acromioclavicular joints, as well as their relationship to bony and soft tissue landmarks, provide an anatomical foundation to develop novel shoulder denervation and perioperative pain management protocols.

Clinical Anatomy for the Innervated Pattern and Boundary of the Subdeltoid Bursa

The aim of this study was to accurately identify the distribution of sensory nerve branches running to bursa with mesoscopic dissection and boundaries following the injection of gelatin into the bursa. Eighteen shoulders of 11 Korean soft cadavers (average age, 65 years; age range, 43 - 88 years) were dissected. The most prominent point of greater tubercle of the humerus (GT) was used as a reference point. The horizontal line passing through GT was used as the x-axis while the vertical line passing through the GT was used as the y-axis. Average distances of the anterior, posterior, superior, and inferior from the GT were 1.9±0.6, 2.4±1.3, 2.1±0.7, and 3.2±1.5 cm, respectively. In 15 cases of 18 shoulders, the anterior branch of the axillary nerve was distributed to the subdeltoid bursa that was running posteriorly. The muscular branch of the anterior and middle parts of the deltoid was distributed to the branch of nerve that was running into the subdeltoid bursa. A branch of the posterior cord of brachial plexus was distributed to the subdeltoid bursa that was running anteriorly in three cases. Most of the branches of the axillary nerve were distributed into the posterolateral area. The branches of the posterior cord of brachial plexus were distributed in the anterolateral area. These results might be useful for preventing residual pain on the anterior shoulder region following an injection for the relief of shoulder pain.

Ultrasound-guided interventions for painful shoulder: from anatomy to evidence

Shoulder pain is a common musculoskeletal disorder of variable etiology, ranging from rotator cuff pathology to peripheral nerve entrapment. Advances in ultrasound (US) technology have allowed static and dynamic evaluation of shoulder problems and most importantly, offer real-time, radiation-free guidance for interventions. The present review aims to describe shoulder anatomy in detail using information from cadaveric models and to illustrate US-guided techniques using clearly labeled figures and videos. The review will also present evidence of specific US-guided therapies for shoulder pain by summarizing landmark studies, systematic reviews, and meta-analyses. The following shoulder structures will be covered: 1) the biceps long head tendon, 2) the acromioclavicular joint, 3) the subacromial-subdeltoid bursa, 4) the glenohumeral joint, 5) the suprascapular nerve, and 6) the axillary nerve.