Shoulder width reduction can be effectively done by reduction of the clavicle, the only horizontally oriented long bone in the body. Because it is a relatively long bone (mean length of 15cms with ranges between 13 and 17 cms) and serves as a strut between the sternum (breast bone) and the scapula (shoulder blade), it is easy to visualize why shortening its length could reduce the outer width of the shoulders.
The common amount of bone removed in aesthetic clavicle reduction is 2cms per side which creates a visible shoulder narrowing effect of about one inch per side. Because the clavicle is not a completely straight bone and does not connect the sternum and the shoulder joint in the same horizontal plane, its ‘collapse’ is not completely linear. At an approximate 30 degree angle a 20mm reduction in bone length does not translate precisely to a true 20mm shoulder width reduction. (closer to 18 mms) But this is overcome by the slight anterior movement of the shoulder which occurs from the non-linear shortening angle which compensates for the ‘loss’ in the non-linear bone length reduction.
While in theory the segment of bone removed in clavicular lengthening can be dine almost anywhere along its length, it is best done closer to he middle third of the bone. The clavicle has most cross-sectional thickness in this area and is exposed to the least stress that comes from shoulder movement which together creates the most favorable environment for rapid bone healing. Equally importantly the placement of the incision in the supraclavicular fossa is the best location for it with the least visible scarring.
The medial third of the clavicle also has a good superior surface which is optimal for plate application. The standard six-hole reconstruction plate lies flat on this bone surface which allows it to be rigidly applied to the bone in the most favorable direction. (straight down through the incision)
Unlike clavicle fractures which have a highly random pattern of bone injury and often occur in the weaker middle third of the clavicle, elective clavicular reduction osteotomies are placed in thicker section of the bone with less surface area of injury that is easily stabilized with plate and screw fixation with its end to end bone contact.
Dr. Barry Eppley