The “coracoid tunnel view”: a simulation study for finding the optimal screw trajectory in coracoid base fracture fixation

Abstract

PurposeCoracoid fractures represent approximately 3–13% of all scapular fractures. Open reduction and internal fixation can be indicated for a coracoid base fracture. This procedure is challenging due to the nature of visualization of the coracoid with fluoroscopy. The aim of this study was to develop a fluoroscopic imaging protocol, which helps surgeons in finding the optimal insertion point and screw orientation for fixations of coracoid base fractures, and to assess its feasibility in a simulation study.MethodsA novel imaging protocol was defined for screw fixation of coracoid base fractures under fluoroscopic guidance. The method is based on finding the optimal view for screw insertion perpendicular to the viewing plane. In a fluoroscopy simulation environment, eight orthopaedic surgeons were invited to place a screw down the coracoid stalk through the coracoid base and into the neck of 14 cadaveric scapulae using anatomical landmarks. The surgeons placed screws before and after they received an e-learning of the optimal view. Results of the two sessions were compared and inter-rater reliability was calculated.ResultsScrew placement was correct in 33 out of 56 (58.9%) before, and increased to 50 out of 56 (89.3%) after the coracoid tunnel view was explained to the surgeons, which was a significant improvement (p < 0.001).ConclusionsOur newly developed fluoroscopic view based on simple landmarks is a useful addendum in the orthopaedic surgeon’s tool box to fixate fractures of the coracoid base.Electronic supplementary materialThe online version of this article (10.1007/s00276-019-02274-z) contains supplementary material, which is available to authorized users.

A guideline for screw fixation of coracoid process base fracture by 3D simulation

“…Trikt et al reported a useful fluoroscopic view based on simple landmarks for fixation of fractures of the coracoid base [31]. Their approach is similar to ours, and an optimal trajectory for the placement of screws in the base fracture of the coracoid process was also obtained.…”

The safe zone of long screw fixation for Ogawa type I coracoid process fracture—Using quadrant method for 3D simulation operation and 2D fluoroscopy verification

“…The axial superimposition of the coracoid process cortical bone essentially formed the boundary line of this fusiform region. When the screws did not penetrate the boundary in the axial perspective view, the screws were located entirely in the bone [17,20]; however, intraoperative reproduction of the fusiform region imaging is relatively tricky. This is related to factors such as lack of reduction for the coracoid process fracture, obstruction of the clavicle, selection of the patient position, light transmission performance of operating bed, or di culty placing the C-arm Mobile X-Ray systems.…”

“…This study stemmed from the expectation of longer screw insertion and the concern about iatrogenic injury caused by screw penetration. Ogawa type I coracoid process fractures are rare; therefore, surgeons have a poor experience in surgical xation, which increases the risk of misplacement of screws [17]. Long screw xation of Ogawa type I coracoid process fracture-related iatrogenic injuries, including neurovascular injuries: the coracoid process is close to the lateral funiculus of the brachial plexus and the axillary vessels, and the distance between the suprascapular nerve vascular area and the neck of the scapula is short, which may be accidentally damaged during screw placement [18,19].…”

Current challenges and controversies in the management of scapular fractures: a review

“…The cephalad and lateral angulations (30 to 40° each) of the fluoroscopic beam directed at the coracoid tip demonstrates the entire profile of the superior coracoid pillar (‘superior pillar view’) and the cephalad and medial angulations (30 to 40° each) of the fluoroscopic beam demonstrates the entire ‘inferior coracoid pillar’. van Trikt et al [ 77 ] described the coracoid tunnel view based on simple landmarks of the scapular bone. They found the optimal passageway of a screw through the coracoid base into the neck of the scapula as the coracoid tunnel.…”

“…As mentioned before, the sharp, hooked, and thin coracoid tip precludes the screw placement starting from this landmark. Therefore, the screw must be placed down the coracoid body through the coracoid base and into the neck of the scapula, which is the coracoid tunnel [ 77 ]. In the vast majority of cases, the drill must be positioned perpendicular to the coracoid process and parallel to the longest axis of the glenoid cavity and the screw must be placed parallel to the glenoid fossa.…”