Computer Assisted Surgical Simulation Versus Model Surgery in Orthognathic Surgery: A Postoperative Comparison of Surgical Outcomes
Surgical correction of craniofacial and dentofacial deformities demands both meticulous and accurate pre-surgical, surgical, and post-surgical planning. Traditional model surgery accomplished this feat, and utilized a team approach to appropriately reposition the patient’s jaws to achieve both a satisfactory esthetic and functional outcome. Although this approach has been tried and proven effective in the last half century, there are inherent inaccuracies and difficulties with such methods. Three factors account for such difficulties: improper mounting of casts, errors in the placement of reference lines on the casts, and errors in measuring the surgical displacement of the segments. These errors can be attributed to the lack of perfect technical ability inherent in human nature, and as such we have searched for more advanced ways to “perfect” pre-surgical planning. One such method involves using computer-assisted surgical simulation (CASS).
CASS is being used as an alternative to the traditional model surgery in order to correct for the inaccuracies. This technology can be used to comprehensively treat any patient undergoing orthognathic surgery by aiding in the cephalometric analysis, fabrication of splints, and computer generated model surgery. By using this technology, surgeons can now plan more complex treatments that would be otherwise difficult with traditional model surgery. While there have been several studies indicating the outcome utilizing traditional model surgery or CASS, we hope to compare them side-by-side at the same institution during the same time period.
Patients and Methods:
We chose 10 patients, 5 who underwent traditional model surgery and 5 who underwent CASS. We primarily chose those patients who underwent corrective jaw surgery and did not have any significant co-morbidities. Both groups contained patients with asymmetry along with other dentofacial deformities. The surgeries were performed since 2010 by the same surgeon (AH) and the amount of follow up ranged from 11 months to 26 months. The evaluations of the patients were all done by the same author (TG) and were done eight weeks postoperatively.
Results:
Our results have demonstrated that patients who underwent CASS experienced a more improved esthetic outcome and fewer complications than those that underwent model surgery. There was improved midline coincidence, better asymmetry resolution and occlusal outcome eight weeks postoperatively in patients that underwent CASS than those that had model surgery performed preoperatively. CASS provides a more improved preoperative analysis, surgical planning and as shown, an improved overall outcome.
References:
1.Ellis E. Accuracy of model surgery: an evaluation of an old technique and introduction of a new one. J Oral Maxillofac Surg. 1990 Nov;48(11):1161-1167
2. Gateno J, Xia J, Teichgraeber JF, et al. Clinical feasibility of computer aided surgical simulation (CASS) in the treatment of complex cranio-maxillofacial deformities. J Oral Maxillofac Surg 2007;65:728-734.