Axillary arch may affect axillary lymphadenectomy

Axillary arch (of Langer): A large-scale dissection and simulation study based on unembalmed cadavers of body donors

Connective or muscular tissue crossing the axilla is named axillary arch (of Langer). It is known to complicate axillary surgery and to compress nerves and vessels transiting from the axilla to the arm. Our study aims at systematically researching the frequency, insertions, tissue composition and dimension of axillary arches in a large cohort of individuals with regard to gender and bilaterality. In addition, it aims at evaluating the ability of axillary arches to cause compression of the axillary neurovascular bundle. Four hundred axillae from 200 unembalmed and previously unharmed cadavers were investigated by careful anatomical dissection. Identified axillary arches were examined for tissue composition and insertion. Length, width and thickness were measured. The relation of the axillary arch and the neurovascular axillary bundle was recorded after passive arm movements. Twenty-seven axillae of 18 cadavers featured axillary arches. Macroscopically, 15 solely comprised muscular tissue, six connective tissue and six both. Their average length was 79.56 mm, width 7.44 mm and thickness 2.30 mm. One to three distinct insertions were observed. After passive abduction and external rotation of the arm, 17 arches (63%) touched the neurovascular axillary bundle. According to our results, 9% of the Central European population feature an axillary arch. Approximately 50% of it bilaterally. A total of 40.74% of the arches have a thickness of 3 mm or more and 63% bear the potential of touching or compressing the neuromuscular axillary bundle upon arm movement.

Anatomical Variations of the Axillary Arch and Implications in Breast Surgery

INTRODUCTION

Langer's axillary arch (AA), the most common anatomical variant in the axillary area of definite clinical significance. This is an updated review of the reported variations in the structure, highlighting its morphological diversity and its potential in complicating axillary lymph node biopsy, lymphadenectomy, or breast reconstruction.

METHODS

A review of the literature concerning the AA published between 1812 and 2020 was performed using the PubMed, Scopus, Embase, and Cochrane medical databases. The frequency, laterality, morphology, origin, lateral attachment points, vascularization, and neurosis of the AA were the parameters retrieved from the collected data.

RESULTS

The prevalence of AA ranged from 0.8% to 37.5%. It is more often unilateral, muscular in nature, and extending from the latissimus dorsi to the pectoralis major. It is vascularized by the lateral thoracic vessels or the subscapular artery and innervated by the thoracodorsal nerve.

CONCLUSIONS

Langer's AA, when present, may complicate surgical procedures in the area; therefore, every surgeon performing breast or axillary surgery should be aware of this entity and its variations to ensure maximal effectiveness and safety in the management of patients.

[Focus on axillary anatomy: The Carl Langer muscle, a great forgotten muscle in the training of medical residents in gynecology and obstetrics]

OBJECTIVE

The Carl Langer muscle is the main anatomical variation of the walls of the axillary area, its incidence being about 7%. The presence of this muscle crossing the anterior edge of the axillary vessels can induce difficulties of exposure, location and dissection during axillary surgery. In addition, it may be responsible for primary lymphedema of the upper limb, venous thrombosis of the axillary vein or thoracic outlet syndrome due to vascular or nervous compression. The objective of this work was to evaluate the state of knowledge on Carl Langer muscle of the gynecology-obstetrics medical residents of the French Eastern Region.

MATERIAL AND METHODS

All the medical residents enrolled in the specialized diploma in gynecology-obstetrics in the 5 regions (Alsace, Bourgogne, Lorraine, Champagne-Ardenne and Franche-Comté) were questioned by means of a questionnaire sent by e-mail.

RESULTS

From February to March 2021, 94 of the 160 medical residents interviewed answered to the questionnaire. Ninety-one of them (97%) did not know Carl Langer's muscle. Three medical residents thought they knew this muscle (3%) but their knowledge was imperfect.

CONCLUSION

Our work has highlighted the general lack of knowledge of this anatomical variation, which is relatively frequent, among French gynecology-obstetrics medical residents who are required to examine or perform surgery on this area. This updated review of the literature should optimize the knowledge of the anatomy of the axillary area and consequently its surgery.

Anterior Axillary Arch: An Anatomic Variant Every Surgeon Operating in the Axilla Should Be Aware of

BACKGROUND

Anterior axillary arch (AAA) is a slip of latissimus dorsi muscle, of variable thickness, which crosses anterior to the axillary vessels and brachial plexus. It is the most common anatomic variant in the axilla and surgeons operating in this area should be familiar with this finding to prevent confusion and complications. The aim of this study is to enhance surgeon's awareness of AAA, report the prevalence, and to describe our experience with this anomaly.

METHODS

An institutionally maintained database was used to identify patients with AAA in a single surgeon's experience, from 2008 to 2019. Patient characteristics, including tumor type, laterality, and pathologic node counts were determined and compared with patients undergoing axillary lymph node dissection (ALND) without this anatomic anomaly.

RESULTS

Nineteen patients with AAA were identified (13 on ALND and 6 during sentinel lymph node biopsy). Indications for ALND included breast cancer (12), melanoma (5), and Merkel cell carcinoma (2). In patients with AAA undergoing an ALND, the median number of lymph nodes pathologically identified was 23 and similar to those without AAA (27, P = 0.14). The prevalence of AAA in patients who underwent ALND was 3.1% (13/422).

CONCLUSIONS

Surgeons who operate in the axilla are likely to encounter an AAA. Knowledge of this variant should improve operative efficiency and may prevent technical errors during an ALND or sentinel lymph node biopsy.

Prevalence and anatomy of the axillary arch and its implications in surgical practice: A meta-analysis

PURPOSE

The following research aimed to investigate the prevalence and anatomical features of the axillary arch (AA) - a muscular, tendinous or musculotendinous slip arising from the latissimus dorsi and that terminates in various structures around the shoulder girdle. The AA may complicate axillary lymph node biopsy or breast reconstruction surgery and may cause thoracic outlet syndrome.

METHODS

Major electronic databases were thoroughly searched for studies on the AA and its variations. Data regarding the prevalence, morphology, laterality, origin, insertion and innervation of the AA was extracted and included in this meta-analysis. The AQUA tool was used in order to assess potential risk of bias within the included studies.

RESULTS

The AA was reported in 29 studies (10,222 axillas), and its pooled prevalence estimate in this meta-analysis was found to be 5.3% of the axillas: unilaterally (61.6%) and bilaterally (38.4%). It was predominantly muscular (55.1% of the patients with the AA), originated from the latissimus dorsi muscle or tendon (87.3% of the patients with the AA), inserted into the pectoralis major muscle or fascia (35.2% of the patients with the AA), and was most commonly innervated by the thoracodorsal nerve (39.9% of the patients with the AA).

CONCLUSION

The AA is a relatively common variant, hence it should not be neglected. Oncologists and surgeons should consider this variant while diagnosing an unknown palpable mass in the axilla, as the arch might mimic a neoplasm or enlarged lymph nodes.

Y-shaped axillary arch muscle: A case report

The axillary arch is a rudimentary part of the latissimus dorsi. Generally it has a single insertion either into tendon of the pectoralis major, coracobrachialis or fascia over the biceps. Clinically, this anomalous muscular slip is known to cause neurovascular compression of nearby structures. The present case reports an unusual bifurcated fibrous insertion of an axillary arch with Y-shaped limbs. The stem of this muscle was a fleshy belly measuring 7.8 cm. The upper limb of this muscle, measuring 5.6 cm, was attached to the fascia covering the short head of biceps brachii and the coracoid process while its lower limb, measuring 5.1 cm, ended by merging with the brachial fascia over the biceps brachii below the deltoid muscle. The persistence of such a Y-shaped anomalous axillary arch might restrict the hyperabduction of the arm and compress the neurovascular structures passing below it.

Langer's arch: a rare anomaly affects axillary lymphadenectomy

Langer's arch is the best-known anatomic variant of definite surgical implication in the region of the axilla. This rare anomaly is a muscular slip extending from the latissimus dorsi (LD) muscle to the tendons, muscles or fasciae around the superior part of the humerus. In this report, we present a rare case of left axillary arch. During modified radical mastectomy for breast cancer, we encountered an abnormal muscle slip crossing the axilla from the LD muscle to the posterior surface of the pectoralis major muscle anterior to the neurovascular structures. Preoperative knowledge is essential to identify such unusual anomaly and avoid potential complications both intra- and postoperatively.

Clinical significance of the axillary arch in sentinel lymph node biopsy

Purpose

The axillary arch is an anomalous muscle that is not infrequently encountered during axillary sentinel lymph node biopsy (SLNB) of breast cancer patients. In this study, we aimed to investigate how often the axillary arch is found during SLNB and whether it affects the intraoperative sentinel lymph node (SLN) identification rate.

Methods

We retrospectively analyzed the correlation between the presence of the axillary arch and the SLN sampling failure rate during SLNB in 1,069 patients who underwent axillary SLNB for invasive breast cancer.

Results

Of 1,069 patients who underwent SLNB, 79 patients (7.4%) had the axillary arch present. The SLNB failure rate was high when the patient's body mass index was ≥25 (p=0.026), when a single SLN mapping technique was used (p=0.012), and when the axillary arch was present (p<0.001). These three factors were also found to be statistically significant by multivariate analysis, and of these three factors, presence of the axillary arch most significantly increased the SLNB failure rate (hazard ratio, 10.96; 95% confidence interval, 4.42-27.21; p<0.001). Additionally, if the axillary arch was present, the mean operative time of SLNB was 20.8 minutes, compared to 12.5 minutes when the axillary arch was not present (p<0.001). If the axillary arch was present, the SLN was often located in a high axillary region (67%) rather than in a general low axillary location.

Conclusion

The axillary arch was found to be a significant factor affecting intraoperative SLN failure rate. It is necessary to keep in mind that carefully checking the high axillar region during SLNB in breast cancer patients with the axillary arch is important for reducing SLN sampling failure.