Anatomical and morphological study of the subcoracoacromial canal.

INTRODUCTION: Many clinical anatomy studies have looked into how variations in the acromion, coracoacromial ligament (CAL) and subacromial space are associated with rotator cuff injuries. However, no study up to now had defined anatomically the fibro-osseous canal that confines the supraspinatus muscle in the subcoracoacromial space. Through an anatomical study of the scapula, we defined the bone-related parameters of this canal and its anatomical variations. MATERIALS AND METHODS: This study on dry bones involved 71 scapulas. With standardised photographs in two orthogonal views (superior and lateral), the surface area of the subcoracoacromial canal and the anatomical parameters making up this canal were defined and measured using image analysis software. The primary analysis evaluated the anatomical parameters of the canal as a function of three canal surface area groups; the secondary analysis looked into how variations in the canal surface area were related to the type of acromion according to the Bigliani classification. RESULTS: Relative to glenoid width, the group with a large canal surface area (L) had significantly less lateral overhang of the acromion than the group with a small canal surface area (S), with ratios of 0.41±0.23 and 0.58±0.3, respectively (P=0.04). The mean length of the CAL was 46±8mm in the L group and 39±9mm in the S group (P=0.003). The coracoacromial arch angle was 38°±11° in the L group and 34°±9° in the S group; the canal surface area was smaller in specimens with a smaller coracoacromial arch angle (P=0.20). CONCLUSION: Apart from acromial morphology, there could be innate anatomical features of the scapula that predispose people to extrinsic lesions to the supraspinatus tendon (lateral overhang, coracoacromial arch angle) by reducing the subcoracoacromial canal's surface area. LEVEL OF EVIDENCE: Anatomical descriptive study.

Particularities of anterior fusion in L4-L5 isthmic spondylolisthesis.

PURPOSE: L4-L5 isthmic spondylolisthesis may be associated with lumbosacral transitional vertebrae (LSTV) and altered venous vascular anatomy. The objectives of this study were to describe the anatomical characteristics of L4-L5 ISPL and the intraoperative difficulties encountered during the approach for anterior lumbar interbody fusion (ALIF). METHODS: This is a retrospective review of 20 ALIFs for L4-L5 ISPL. The anatomy of the common iliac veins confluence and the position of L4-L5 with respect to the projection of the iliac crest were analysed on CT-scan. Intraoperative difficulties were noted. RESULTS: A LSTV was present in 60% of cases, associated with abnormally distal positioning of L4-L5 below the projection of the iliac crest. The common iliac veins confluence was abnormally proximal compared to L4-L5. No complication was noted, even if the approach was unusually difficult in 11 cases. DISCUSSION: Anterior lumbotomies are difficult because the left common iliac vein courses transversely across the left anterolateral aspect of the L4-L5 disc and L5 vertebral body, increasing the risk of vascular injury. Those difficulties have led us to abandon lumbotomies to treat L4-L5 ISPL to favour a pure anterior approach (midline) or an exclusive posterior approach. LEVEL OF EVIDENCE: IV (retrospective study).

[Thoracic outlet syndrome in a child: a rare pediatric diagnosis]. / Syndrome du défilé thoraco-brachial par côte surnuméraire : un diagnostic rare en pédiatrie.

Thoracic outlet syndrome (TOS) is a rare pediatric syndrome and few cases have been reported in the literature. The authors report the case of a 10-year-old boy with generalized arm pain and neck stiffness. The angiocomputed tomography revealed the presence of a TOS caused by an additional cervical rib and stenosis of the sub-clavian artery. The resection of this rib relieved the patient of his pain during a full year following surgery. This case reminds us that children can also be affected by TOS. When a cervical rib causes TOS, a resection is often necessary.