Reduction in shoulder width (shoulder narrowing surgery) has recently evolved into a safe and effective technique by removing a segment of the clavicle bone. By reducing each clavicle in length by 2 to 3cm the external shoulder size (bideltoid width) is equally narrowed. The two cut blunt ends of the clavicle, when put back together with plate and screw fixation, provides an excellent site for primary bone healing that heals as good if not better than many clavicle fractures. With a sequential range of arm motion protocol patients are back to near full range of motion by six weeks after surgery despite having bilateral clavicle osteotomies.
Broadening of the shoulders (shoulder widening surgery), however, poses different considerations than shoulder narrowing surgery from a clavicle osteotomy pattern standpoint. While clavicle reduction can really only be done with a straight perpendicular bone cut, non-bone graft clavicle lengthening can be done by two different osteotomy patterns….both of which ‘stretch’ the bone out leaving a thinner expanded bone segment.
One type of clavicle lengthening osteotomy is the oblique pattern. Done at a 30 to 40 degree angle at the inner third of the clavicle, the outer clavicle segment slides laterally along the oblique cut line. (this is similar to the sliding genioplasty of the chin) Because the bone ends of the cuts are thin there is a limit as to how much lengthening can be done and still have adequate bone stock to heal. This is in the range of 15 to 18mms at most. A long 2.7mm plate is placed superiorly and bone putty is applied around the thinned bone areas under the plate to expedite healing and help restore a more normal bone diameter.
But at lengthening distance 20mms or more the two bone ends have limited contact and what is in contact is very thin bone at the ends of the osteotomy cuts. Even with plate fixation and bone putty, primary bone healing with an adequate diameter is much more tenuous.
The second type of clavicle lengthening osteotomy is the modified sagittal split pattern. In his technique partial thickness perpendicular bone cuts are made on opposite sides of the clavicle 4 cms apart. They are then connected by a midline cut that goes down the center of the bone. (this is very similar to the sagittal split osteotomy of the mandibular ramus) This creates thicker bone ends on each side of the cuts that when put together after lengthening has a normal central bone diameter. The missing half diameter of the bone is on opposite sides of the bone which are filled with bone putty after plate application.
Because of the thicker bone segments some greater shoulder widening may be possible. By lengthening the location of the two half thickness bone cuts (greater than 4cms) some greater lengthening can be achieved with more central bone contact.
In shoulder widening surgery two different osteotomy patterns are possible, each with their own advantages and disadvantages. The oblique osteotomy is simpler to perform but leaves a thinner bone stock to heal and has limitations in its shoulder widening effect. The sagittal split osteotomy requires greater technical precision to perform but leaves a thicker central bone stock and can offer a bit more shoulder widening effect. More clinical experience is needed to determine whether these osteotomy patterns have substantial clinical differences in outcomes and bone healing.
Dr. Barry Eppley