Orthognathic surgery: Is surgery first approach a viable option in orthognathic surgery?

Abstract

Orthognathic surgery, also known as corrective jaw surgery, is a complex procedure used to correct significant skeletal discrepancies in the jaws and face. Historically, orthognathic surgery has been reserved for cases where other treatment modalities have failed. However, in recent years, there has been growing interest in exploring the viability of adopting an orthognathic surgery-first approach. Proponents of surgery first approach argue that immediate surgical intervention can provide substantial advantages. By addressing the underlying skeletal irregularities early on, orthognathic surgery may offer more predictable and long-lasting results. Moreover, it can improve aesthetic outcomes, enhance facial harmony, and alleviate functional issues such as malocclusion, speech difficulties, and temporomandibular joint disorders. Additionally, early orthognathic surgery may prevent or mitigate the need for subsequent orthodontic or orthopedic interventions, potentially reducing overall treatment time and cost. This view point aims to identify the potential benefits and considerations surrounding the use of orthognathic surgery as a first-line treatment option.

INTRODUCTION

Orthognathic surgeries are designed to correct skeletal deformity and require appropriate surgical planning and orthodontic treatment. Conventional orthognathic approach or a three-stage approach requires 15–24 months of presurgical orthodontics as well as 7–12 months for postoperative orthodontics. This phase of presurgical orthodontics causes worsening of the facial profile due to decompensation of dental arches. Surgery-first approach (SFA) was proposed by Nagasaka et al. in 2009[1] to overcome the disadvantages of this therapeutic sequence. SFA avoids prolonged presurgical orthodontic preparation and is set in motion with the surgical correction of jaws. This approach primarily has two main advantages: shorter treatment time and early improvement in facial aesthetics. This is possible in part due to the advancement in 3-D imaging and simulation for precise treatment planning.

REVIEW OF LITERATURE

An electronic search of the literature directly relating to orthognathic surgeries and SFA was conducted. Multiple words and combinations of words were used to search different databases. The articles included were original research papers, case reports, and review articles published from 1986 through 2022. The search strategy consisted of searching the keywords orthognathic surgery, SFA, approaches to orthognathic surgery within the PubMed database, a search within PubMed-related articles, and a search within the references list of the selected articles. Abstracts of all these publications were studied, and an attempt was made to retrieve the full texts of these articles. There were several limitations to our study. Given the retrospective nature of the study, we were able to assess outcomes only through follow-up visits documented in the electronic records and one of the most important limitations of our search was that it remained restricted to English literature only. Our data search was up to November 20, 2022. Of 144 studies and publications identified on the initial search of all databases, 52 were excluded as they were not directly relevant to the subject matter studied. The remaining 10 publications were examined and analyzed for the purposes of this review. Then, we searched for cross-references and cited articles used by other authors. These were in significant numbers, so we used them as per our relevance and findings.

INDICATIONS

SFA basically is a team approach between orthodontists and maxillofacial surgeons. It is desired that the candidates for the SFA have well aligned to mild crowding of teeth, flat to mild curve of Spee, and normal to mild proclination/retroclination of incisors and minimal transverse discrepancy. Even though surgery first technique can be applied to Class II as well as Class III malocclusions, the majority of cases reported in the literature have had Class III malocclusion.[2,3,4]

When comparing patients having transverse discrepancy, there was no significant difference between SFA and conventional approach.[5,6] Patients with deep curve of Spee showed a higher tendency to relapse. In view of postoperative occlusal stability, patients with mild overbite have better results than those with a deep overbite. Patients with bimaxillary protrusion are also indicated for SFA.[7,8,9,10]

ADVANTAGES OVER CONVENTIONAL APPROACH

In SFA, as the surgical procedure is performed prior to the orthodontic correction, the hard and soft tissue imbalance is corrected first. This aids in easier alignment of teeth in the postsurgical phase as the jaws are in the desired position. The early jaw deformity correction prevents the soft tissue profile from worsening during the first stage of the conventional approach. Undergoing surgical correction addresses the chief complaint at the very start of therapy, minimizing serious psychosocial difficulties. Patients have the freedom to select the timing of surgery to accommodate the postsurgical recovery period. There is a reduction in the duration of treatment time because of two major factors: correction of hard and soft tissue disharmony before initiating tooth movement done with surgery first and the regional acceleratory phenomenon (RAP) that accelerates postsurgical tooth movement.

Regional Acceleratory phenomenon (RAP) was well described by Harold Frost in 1989. Serum alkaline phosphatase and C-terminal telopeptide of collagen I are two bone markers studied for RAP. After osteotomy, active bone remodeling with rapid metabolic activity within the healing tissue is present. This phenomenon can be utilized by orthodontists following orthognathic surgery to accelerate tooth movement. The result of one such study shows that surgery triggers 3–4 months of higher osteoclastic activities and metabolic changes in the dentoalveolus, with peak activity in 1–2 months after surgery.

In conventional treatment, the decompensation is completed before surgery, thus it is difficult or impossible to recover from a surgical error during postsurgical orthodontic treatment. Unlike in SFA, compensation of surgical error or skeletal relapse is possible later with the help of the skeletal anchorage system. Reports indicate that a significant number of temporomandibular disorder symptoms are taken care of along with excellent results in patients with mandibular prognathism using SFA. In patients with mandibular retrognathia, early advancement procedures help to immediately increase the dimension of the upper airway, providing an expedient solution to patients having obstructive sleep apnea.

LIMITATIONS

Cases requiring extractions are especially very difficult to plan when performing SFA. The planning process is very time-consuming in contrast to total treatment time. Predicting the final occlusion remains challenging with SFA due to multiple dental interferences. Chewing becomes difficult immediately after surgery due to imperfect occlusion. SFA may yield poorer postoperative stability than the conventional orthognathic approach (COA). The first factor is the unstable occlusion acquired after surgery in SFA, which is unfavorable to postoperative stability. In sagittal split osteotomies performed using SFA, the compressive force of the masseter muscle applied to the bone segment is the main cause of relapse. However, a stable occlusion aids in bone stability and decreases the chances of mandibular relapse.[4] The second factor involves the mandibular autorotation after the removal of the surgical splints or postoperative orthodontic correction of occlusal interference. The third factor is the high degree of tooth movement in the postoperative orthodontic phase. The regionally accelerated phenomenon helps us hasten postoperative orthodontic tooth movement. This may also cause immediate rotational relapse as well. Mandibular protrusive relapse may occur within the initial stage of postoperative orthodontic treatment.[6]

AUTHORS IN SUPPORT FOR SURGERY FIRST APPROACH AS VIABLE OPTION

Yang L et al.[2] in 2017 compared SFA and CTM (conventional three-stage method) by performing a systematic review (SR). The authors hypothesized that there would be no significant outcome difference between the two strategies. The meta-analysis of 10 retrospective studies including 513 study subjects showed SFA as more efficacious with significantly shorter treatment duration with similar stability when compared with CTM. On the other hand, CTM required significantly short postsurgical orthodontic treatment time. Similarly, Ellen Wen-Ching Ko and associates identified parameters related to skeletal stability for Class III malocclusion treated with SFA.[3] They found out that the mean setback at the innermost point of the contour of the mandible was 11.19 mm and the mean relapse rate was 12.46%. Statistically, significant correlations with the amount of relapse were found with amount of surgical setback, overbite, overjet, and depth of curve of Spee, of which mandible skeletal relapse increased with an increase in overbite. Therefore, an initial overbite can be a predictor for possible skeletal relapse of mandibular setback. The study also reported minimal differences in stability between conventional orthognathic surgery and surgery-first orthognathic surgery.

Park K et al.[4] in 2014 carried out a study to compare postoperative stability following bimaxillary surgery performed with the conventional or SFA for patients with Class III malocclusion where they found no statistical difference between the results obtained by the SFA and conventional bimaxillary surgery during the first 6 months.

H.B. YU, L.X. Mao, and X.D. Wang et al. (2015)[8] conducted a retrospective study of 50 cases undergoing SFA without presurgical orthodontic treatment. The presurgical orthodontic treatment may take 12–24 months depending on the complexity. At the same time, there is a progressive deterioration in facial aesthetics and dental function preoperatively. In this study, total orthodontic treatment time was reduced to about 15 months. SFA does not compromise the quality of treatment in terms of facial aesthetics or occlusion. Reasons for shorter orthodontic treatment were due to (1) dental decompensation being resolved in part by surgery itself and (2) regional accelerated phenomenon postoperatively shortens the treatment period required for orthodontic tooth movement as the orthognathic surgery triggers a 3- to 4-month period of higher osteoclastic activity and metabolic changes in the dentoalveolar bone postoperatively. The indications for SFA include skeletal class II/III malocclusion, skeletal open bite, bimaxillary protrusion, and facial asymmetry. The mean duration of postoperative orthodontic treatment was 14.9 months, which is shorter than that of traditional joint orthognathic–orthodontic treatment. Patients were satisfied with the results of treatment. No relapse was recorded during 6–12 months of follow-up.[8]

Selene Barone, Anne Morice, Arnaud Picard, and Amerigo Giudice (2020)[9] reviewed skeletal stability, treatment time, surgical complications, and quality of life in SFA and COA. Six databases were accessed up to May 2020 to obtain all SRs. Ten SRs were included in this review. A good stability of the jaws was assessed both with SFA and COA by most of low or critically low-quality SRs. Less treatment time was reported for SFA than COA with moderate quality level SRs. A slightly higher complication rate was recorded with SFA than COA by SRs with low or moderate quality. A better quality of life with SFA than COA was reported by moderate or low-quality SRs. The review concluded that SFA may represent a reasonable alternative to COA.

AUTHORS NOT CONSIDERING SURGERY FIRST AS A VIABLE OPTION

Contrary to the above-mentioned concept, Park HM, Yang IH, Choi JY, Lee JH, Kim MJ, and Baek SH et al. in 2015[5] conducted a study on postsurgical relapse in Class III patients treated with the CTM and SFA and found a higher incidence of unstable occlusion in the postsurgical phase leading to relapse in patients without presurgical orthodontic treatment. They also concluded that not only the approach for surgery but also skeletal- and dental-related factors like occlusal prematurity, and vertical discrepancy influences postoperative stability.

Tadaharu Kobayashi, Izumi Watanabe, and Ken Ueda et al. (1986)[6] concluded in their study that appropriate preoperative orthodontic treatment minimizes postsurgery relapse. Tendency to relapse was greater in cases that had larger posterior or lateral movements of mandible.

CONCLUSION

Case selection for SFA must be done with great caution. Cases most suitable for SFA include those with well aligned to mild crowding of teeth, flat to mild Curve of Spee, normal to mild proclination/retroclination of incisors and minimal transverse discrepancy. Considering the parameters for the SFA, appropriate treatment planning with model surgery and 3-D radiological analysis are required to have a better outcome. In our experience, there is a definitive reduction in treatment time with the SFA. Significantly SFA bypasses the decompensatory nonaesthetic phase for the patient during presurgical orthodontic, which is considered to be an important limitation of the conventional approach.

The SFA is still in its infancy and many more studies and reports are required to firmly establish this as a viable treatment option. At present very few articles comment on the complications associated with SFA or on the long-term outcomes. Therefore, it is still early to comment on SFA as a viable alternative to the conventional approach in all cases of facial deformity.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.