Unlike shoulder augmentation there is only one method to achieve shoulder width reduction. Shortening the length of the horizontally oriented clavicle bone allows the transverse width of the shoulders to move inward. This is done by performing a small segmental osteotomy at the inner third of the clavicle. Putting the two ends of the bone back together creates the narrowing effect. While the clavicle is not shaped like a completely straight cylinder, shortening its length creates a primary inward movement.
Putting the cut clavicle bone back together requires plate and screw fixation for stability and to allow primary bone healing. While extensive biomechanical studies have been done on the plate and screw fixation of clavicle fractures, no such work has been done on elective clavicle osteotomes. And certainly no studies have been done on the biomechanics of the clavicle bone that has been shortened which may or may not be different than a longer clavicle bone.
Drawing from work done on clavicle fracture repair, it is known that superior plate application provides better stability than an anterior plate placement. Also stainless steel plates of 3.5mm profile are used and are often quite long. But many clavicle fractures occur in the mid-or distal shaft locations and are often have angular or spiral fracture patterns. This poses different stability concerns and stability needs that are somewhat different than an elective osteotomy done on the inner third of the clavicle. It is somewhat analogous to comparing the fixation needs of a mandibular angle fracture vs that of a sagittal split ramus osteotomy.
As a result my current approach is to use 2.7mm titanium compression plate with either two or three holes on each side of the reunited bone segments. Bicortical screw placement is important and the length of the screws needed can be measured on the removed bone segment. It is important to add on the thickness of the plate when calculating screw lengths so they fully engage opposite cortex.
Because the incisional length is small long spanning plates can not be used and it is not even known if it is really necessary. Shortening the plate length to a few holes on each side seems adequate particularly with a compression style plate. But it is important to prevent rotational stresses when the primary fixation plate is shorter on a round bone shape. The application of second plate to resist rotation stress in the primary plate can be done either above or below the primary plate. This plate can use shorter monocortical screws.
Double plate fixation of clavicle reduction osteotomies provides good fixation that allows primary bone healing but also permits early mobilization in the first few weeks after surgery.
Dr. Barry Eppley