A pilot study of blood supply of the coracoid process and the coracoid bone graft after Latarjet osteotomy.

Latarjet osteotomy is still one of the most reliable and commonly used surgeries in treating recurrent anterior shoulder dislocation. The coracoid process (CP) is the main structure of this surgery. However, the blood supply of CP is not fully understood, and the extent of destruction of blood supply of coracoid bone graft after Latarjet osteotomy procedure is still controversial. Five embalmed cadaveric upper limbs specimens were employed for macro observation of the blood supply of CP. The conjoint tendon (CT) and CP interface were dissected for histology. Sixteen fresh frozen shoulder specimens were used for perfusion and micro CT scanning. Eight specimens were used to present the whole vessel structure of CP. The other eight underwent Latarjet osteotomy procedure. The coracoid bone grafts in both groups were scanned to clarify the remnant blood supply. It was found that the CP was nourished by supra-scapular artery (SSA), thoracic-acromial artery and branch from second portion of the axillary artery (AA). After Latarjet osteotomy procedure, no artery from CT was detected to penetrate the CP at its attachment. Only in one specimen the blood vessel that originated from the CT penetrated the bone graft at the inferior side. Therefore, most of the blood supply was destroyed although there is a subtle possibility that the vessels derived from the CT nourished the inferior side of the CP. In a nutshell, CP is a structure with rich blood supply. The traditional Latarjet osteotomy procedure would inevitably cut off the blood supply of the coracoid bone graft.

The coracoid process is supplied by a direct branch of the 2nd part of the axillary artery permitting use of the coracoid as a vascularised bone flap, and improving it's viability in Latarjet or Bristow procedures.

BACKGROUND: A comprehensive understanding of the anatomy of the vascular supply of the coracoid is needed to ensure that the coracoid remains vascularised in order to optimize bone union during any coracoid transfer procedures. It is the purpose of this study to present an anatomical overview of the blood supply of the coracoid process, describing a previously unidentified vessel that arises directly from the axillary artery and nourishes the coracoid process, permitting the coracoid to be used as a free bone flap. METHODS: An anatomical study examining the blood supply to the coracoid process of the scapula was performed in 14 shoulders from 7 fresh frozen (unembalmed) adult cadavers. In addition, the vascular supply to the coracoid was studied in 22 shoulders in patients during operations around the anterior shoulder. RESULTS: In all the cadaveric shoulders studied there was a single consistent direct branch of the second part of the axillary artery that supplied the distal 2-3 cm of the coracoid process with a corresponding vein. The mean pedicle length for the artery was 4.46 cm (range 3.1-5.6 cm). This artery originated from the axillary artery from the antero-lateral position in 6, lateral position in 3 and posterolateral position in 5 shoulders. The mean pedicle length for the vein was 5.8 cm (range 4.5-7.8 cm). The vein joined directly to the axillary vein in 3 shoulders and via another tributary (parallel to the axillary vein) in 9 shoulders. The diameter of the artery and vein averaged 1-1.5 mm. The clinical study confirmed the findings of the cadaveric study. CONCLUSION: Our anatomical cadaveric and clinical studies demonstrate the presence of a previously unidentified direct arterial branch from the second part of the axillary artery supplying the anterior 2-3 cm of the coracoid process of the scapula. This consistent vessel and accompanying vein should be preserved for any surgical procedure that involves transfer of the coracoid process, such as the Laterjet and Bristow procedures for shoulder dislocation and can be used for free transfer of the coracoid where a small vascularised bone flap may be required.

Proximity of the Coracoid Process to the Neurovascular Structures in Various Patient and Shoulder Positions: A Cadaveric Study.

PURPOSE: To examine and compare the distances from the anteromedial aspects of the coracoid base and the coracoid tip to the neurovascular structures in various patient positions. METHODS: The experiment was conducted in 15 fresh-frozen cadavers. We dissected 15 right and 15 left shoulders to measure the distances from the anteromedial aspects of the coracoid base and the coracoid tip to the lateral border of the neurovascular structures in the horizontal, vertical, and closest planes. The measurements were performed with the cadavers in the supine, lateral decubitus, and beach-chair positions. With cadavers in the beach-chair position, we evaluated 5 arm postures (arm at side, 45° of abduction, 90° of abduction, 45° of forward flexion, and 90° of forward flexion). RESULTS: The shortest distance from the coracoid base to the neurovascular structures was found in the beach-chair position with arm at side in the horizontal plane (27.4 ± 4.9 mm) and 90° of abduction in the vertical (21.8 ± 4.2 mm) and closest (19.5 ± 4.2 mm) planes. The distances in each plane were statistically significant compared with the supine and lateral decubitus positions (P < .005). Between the coracoid tip and the neurovascular structures, the shortest distance was found in the beach-chair position with 90° of abduction, with 29.3 ± 7.7 mm, 20.8 ± 4.9 mm, and 18.5 ± 5.1 mm in the horizontal, vertical, and closest planes, respectively. The distances were statistically significant in all planes compared with the supine and lateral decubitus positions (P < .005). CONCLUSIONS: Shoulder surgery in the area of the coracoid process is safe, especially with the patient in the supine position. The distance from the coracoid process to the neurovascular structures was closest in the beach-chair position with 90° of arm abduction. CLINICAL RELEVANCE: This study determined the distances between the coracoid process and the neurovascular structures during surgery around the coracoid process.