J Oral Maxillofac Surg61:1113-1114, 2003

Control of the Proximal Segment DuringApplication of Rigid Internal Fixation ofSagittal Split Osteotomy of the Mandible

Gerald Alexander, DDS,* and Mark Stivers, DDS†

Control of the proximal fragment during sagittal ra-mus osteotomy is important to achieve a stable de-sired change in centric relation of the mandible aftereither anterior or posterior repositioning. Failure toaccomplish this often leads to decreased stability ofthe surgical result, adversely affects the temporoman-dibular joint apparatus, and decreases masticatory ef-ficiency.1 Failure to control the proximal fragmentcan result in occlusal discrepancies that cannot befully corrected with orthodontic therapy.

Several methods of controlling the proximal frag-ment have been reported. Originally, clamping thefragments after maxillomandibular fixation and seat-ing the condyle before screw fixation was commonpractice.1-4 Unintended posterior open bites can oc-cur with this method. Other modalities have includedwiring the segments (as was common before rigidfixation), then placement of rigid fixation.2 Nicker-son5 described a technique of filleting the proximalend of a plate, engaging the anterior border of theproximal fragment while passively seating the con-dyle. This position is then maintained by placingscrews in the plate at the anterior fragment. Placing awire in the anterior superior aspect of the seatedproximal fragment before screw fixation has alsobeen done.2 Another common procedure involvesplating. The proximal fragment is secured to the platewith screws, allowing the unsecured anterior portionof the plate to be used to seat the proximal fragmentbefore the final screw placement in the anterior por-tion of the plate. Epker et al1 describe a techniqueusing a condyle proximal segment control device.Some authors describe a technique in which the prox-

imal segment is seated and plated to the zygomabefore the osteotomy. The plate is removed, osteoto-mies are completed, and occlusion is established;then the plate is reapplied and rigid fixation isachieved with the condyle in the plated position.6,7

Our experience has shown that the most practicaland predictable method of positioning and fixating theproximal fragment of the sagittal split osteotomy in-volves a controlled screw fixation. After maxilloman-dibular fixation, a transbuccal trocar system with apointed rotating cannula (K.L.S. Martin, Jacksonville, FL)is passed to the region corresponding to the anterosu-perior portion of the proximal fragment (Fig 1). Thepoint of the cannula is adjusted so that the pointedportion of the cannula is anterior. Then, an initial mono-cortical hole of small diameter is drilled into the anteriorsuperior aspect of the proximal fragment. The pointedend of the cannula is placed in this small hole, and thetrocar is removed, allowing control of the proximalfragment and the engaged cannula. The proximal frag-ment is then brought posteriorly and slightly superiorlywith the aid of finger pressure applied extra orally at theangle. With the condyle being gently seated and beingheld in position with the extraoral finger and the can-nula point, the first bicortical hole can then be drilledwithout changing the position of the cannula (Fig 1,inset). The remaining bicortical screw can then beplaced in the normal fashion.

This technique allows for accurate and predictableproximal fragment placement without the use of ex-cessive plating hardware.

References1. Epker BN, Wylie G, Wylie A: Control of the condylar-proximal

mandibular segments after sagittal split osteotomies to advancethe mandible. J Oral Maxillofac Surg 62:613, 1986

2. Wolford LM, Bennett MA: Modification of the mandibular ramussagittal split osteotomy. J Oral Maxillofac Surg 64:146, 1987

3. Alexander G: Modified Kocher clamp for fragment stabilizationafter sagittal ramus osteotomy. J Oral Maxillofac Surg 42:649, 1985

4. Jeter TS, Van Sickels JE, Dolwick MF: Modified techniques forinternal fixation of sagittal ramus osteotomies. J Oral MaxillofacSurg 42:270, 1984

5. Nickerson TS: Stabilization of the proximal segment in sagittal splitosteotomy: A new technique. J Oral Maxillofac Surg 41:683, 1983

6. Hiatt WR, Schelkun PM, Moore DL: Condylar positioning inorthognathic surgery. J Oral Maxillofac Surg 46:110, 1988

7. Merten HA, Halling F: A new condyler positioning technique inorthognathic surgery. J Craniomaxillofac Surg 20:310, 1992

*Attending Surgeon, Oral and Maxillofacial Surgery, UMC-

Fresno/Community Medical Centers; Private Practice, Fresno Oral/

Maxillofacial Surgery Group, Fresno, CA.

†Resident, Oral and Maxillofacial Surgery, UMC-Fresno/Commu-

nity Medical Centers, Fresno, CA.

Address correspondence and reprint requests to Dr Alexander:

Oral and Maxillofacial Surgery, UMC-Fresno/Community Medical Cen-

ters, 445 South Cedar Ave, Fresno, CA 93702; GArunsii@yahoo.com.

© 2003 American Association of Oral and Maxillofacial Surgeons

0278-2391/03/6109-0024$30.00/0

doi:10.1016/S0278-2391(03)00329-X

1113

FIGURE 1. Seating of proximal segment using both point of sheath engaging the first monocortical hole drilled and extra oral finger pressure gentlyseating condyle. (Inset) Engaged sheath and the drill ready for the first bicortical hole.

1114 ALEXANDER AND STIVERS