|Year : 2021 | Volume
| Issue : 2 | Page : 106-110
Comparative evaluation of contralateral pterygoid dysjunction versus nondysjunction in unilateral combined maxillomandibular distraction osteogenesis
Indranil Deb Roy1, Serat Rahman2, Pushpa Kumari3
1 Armed Forces Dental Clinic, New Delhi, India
2 Command Military Dental Centre (EC), c/o 99 APO Pin: 900285, Mumbai, Maharashtra, India
3 INDC Danteshwari, Mumbai, Maharashtra, India
|Date of Submission||20-Sep-2020|
|Date of Decision||12-Feb-2021|
|Date of Acceptance||18-Feb-2021|
|Date of Web Publication||17-Sep-2021|
Indranil Deb Roy
Armed Forces Dental Clinic, New Delhi
Source of Support: None, Conflict of Interest: None
Aim: To prospectively evaluate efficacy of Unilateral Combined Maxillomandibular Distraction Osteogenesis in cases of facial asymmetry managed by Lefort I osteotomy with oblique ramal osteotomy with or without contralateral pterygoid dysjunction.
Objective: To evaluate the post op result in terms of facial symmetry, amount of distraction achieved, occlusal cant changes and radiological findings.
Patient and Methods - 9 cases of facial asymmetry were divided into two groups alternatively. Group I cases were managed with Lefort I osteotomy with bilateral pterygoid dysjunction with contralateral wire cinch on normal side along with oblique ramal osteotomy and fixation of distractor in osteotomized mandibular segments. Group II cases were managed without pterygoid dysjunction and cinch on contralateral normal side with all other procedures being same. Distraction of 9-16mm were carried out depending upon the requirement.
Results: No significant difference was noted between the study groups at a follow up period of six months in terms of facial symmetry at maxillary and mandibular bases, and occlusal cant.
Conclusion: Contralateral Pterygoid dysjunction on unaffected side is not necessary in Unilateral Combined Maxillomandibular Distraction Osteogenesis.
Keywords: Distraction osteogenesis, facial asymmetry, occlusal cant
|How to cite this article:|
Roy ID, Rahman S, Kumari P. Comparative evaluation of contralateral pterygoid dysjunction versus nondysjunction in unilateral combined maxillomandibular distraction osteogenesis. J Dent Def Sect. 2021;15:106-10
|How to cite this URL:|
Roy ID, Rahman S, Kumari P. Comparative evaluation of contralateral pterygoid dysjunction versus nondysjunction in unilateral combined maxillomandibular distraction osteogenesis. J Dent Def Sect. [serial online] 2021 [cited 2022 Jan 25];15:106-10. Available from: http://www.journaldds.org/text.asp?2021/15/2/106/326223
| Introduction|| |
Facial asymmetry has been treated since time immemorial. Hemifacial microsomia is one of the most common causes of nontraumatic facial asymmetry. Hemifacial microsomia was first explained by Gorlin and Pindborg in 1964 and involves malformations of structures derived from the first and second branchial arches. The condition is unilateral in 70%–80% of cases and involves the craniofacial skeleton, muscles of mastication, ears, nervous system, and overlying soft tissues of the cheek. The incidence reported in the literature varies between one in 3500 and one in 5600 live births. In 1969, Pruzansky described three types of hemifacial microsomia based on the severity of the mandibular hypoplasia. Other common causes are condylar hypoplasia or hyperplasia, hemifacial hypertrophy, fibrous dysplasia, etc. Bony reconstruction as well as soft-tissue contouring is required for patients with moderate-to-severe deformities. Traditionally, facial skeletal reconstruction was performed with osteotomies and bone grafting. More recently, distraction osteogenesis (DO) has proven to be successful in achieving bone lengthening. For select cases, DO has lessened the need for major skeletal procedures and has allowed earlier surgical intervention., In the recent past, DO has been extensively used to treat facial asymmetry by means of single jaw or bijaw distraction., The goal of such therapy is to elongate the hypoplastic ramus along with the midfacial component to correct the posterior facial height and occlusal cant. Maxillomandibular DO is one of the reliable procedures in the management of facial asymmetry, and the success of such treatment has been well documented.,,
The aim of this study was to prospectively evaluate the efficacy of unilateral combined maxillomandibular DO in cases of facial asymmetry managed by LeFort I osteotomy with oblique ramal osteotomy with or without contralateral pterygoid dysjunction.
The objective of this study was to evaluate postoperative results in terms of facial symmetry, amount of distraction achieved, and occlusal cant changes.
| Patients and Methods|| |
The protocol of the study was reviewed and approved by the Institutional Review Board of tertiary care dental centre where study was conducted, and written informed consent was obtained from all the patients selected for the study. Nine cases of facial asymmetry were selected for the study. All the cases had unilateral flattening of face, deviation of chin, and marked occlusal canting. Condylar form and function of temporomandibular joint (TMJ) were within normal limits.
Preoperative evaluation included thorough clinical assessment and other investigations including orthopantomogram, posterior-anterior, and lateral cephalogram apart from other investigations as deemed necessary. Presurgical orthodontic consultation was sought in all the cases. All the cases were nonsyndromic without any history of trauma.
Cases were divided into two groups alternatively to reduce the bias. Group I had five patients while Group II had four cases.
Group I: Cases of Group I were managed with oblique ramal osteotomy along with LeFort I osteotomy with pterygoid dysjunction bilaterally followed by 26G stainless steel wire cinching on the contralateral side (noneffected side) [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5].
|Figure 2: LeFort I osteotomy with bilateral pterygoid dysjunction followed by cinching on normal side|
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Group II: Cases of Group II were managed with oblique ramal osteotomy along with LeFort I osteotomy with unilateral pterygoid dysjunction on the effected side only.
Erich's arch bar was placed preoperatively in both the arches.
Ramus was exposed through submandibular approach. An oblique ramal osteotomy in anterosuperior and posteroinferior fashion was carried out above the level of angle of mandible, and a Zurich monoplanar distractor was placed as per the predetermined vector. Efficacy was checked by activation of the distractor. Subsequently, LeFort I osteotomy was performed with bilateral pterygoid dysjunction and cinching on the contralateral (normal) side for Group I cases.
Similar procedure was applied in Group II cases except that no pterygoid dysjunction was performed on the contralateral (normal) side.
Latency period of 5 days was observed in all cases. Prior to the commencement of distraction maxillomandibular fixation was done on the 5th postoperative day. Distraction at the rate of 0.5 mm 12 h was carried out. Postdistraction consolidation period of 8 weeks was observed in all cases. Evaluation was done 6 months postoperatively.
Since the study design was comparative evaluation of two procedures, only comparative values of subjects of two groups were taken into account. Occlusal plane angle with tangent to supraorbital rim was evaluated pre- and postoperatively to compare occlusal cant [Figure 6]. Midfacial symmetry was compared by linear measurement between perpendiculars drawn from jugum to midsagittal reference line on affected and unaffected sides [Figure 7]. This corresponds to the comparative maxillary height change postdistraction. Lower third or mandibular symmetry was measured using the linear measurement from condylion to antegonion combined with antegonion to menton on the unaffected and operated site pre- and postoperatively keeping in mind the anteroinferior direction of the vector [Figure 8].
|Figure 7: Midfacial symmetry: Linear measurement between perpendiculars drawn from jugum to midsagittal reference line on affected and unaffected sides|
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|Figure 8: Lower third symmetry: Linear measurement from condylion to antegonion combined with antegonion to menton|
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| Results|| |
The study was conducted at a tertiary care dental centre in New Delhi, India. The mean age of patients in both the groups was 20.6 years and 20.0 years, respectively. Total amount of distraction achieved was between 12 and 13 mm in both the groups. Occlusal cant changes and changes in maxillary and mandibular symmetry in both the groups were also comparable at a follow-up of 6 months. None of the data obtained were of statistical significance (P ≥ 0.05) [Table 1].
| Discussion|| |
Restoration of facial symmetry in hemifacial microsomia and related disorders, especially when associated with a soft-tissue deficiency, continues to be a difficult and challenging procedure for maxillofacial surgeons. DO, first described for orthopedic surgery, has incontestably been advocated as an effective technique in the management of craniofacial deformities. Initially, surgical procedures for correction of hemifacial microsomia encompassed DO for lengthening of hypoplastic mandible alone without any surgical procedure on the maxilla. It was stressed that in patients with hemifacial microsomia, it is most important to increase the vertical dimension of the ramus and deliberately create a posterior open bite on the affected side. Ortiz Monasterio et al. first reported and popularized the technique of combined maxillomandibular distraction in adults to avoid unforeseen and difficult to manage occlusal discrepancy. Various intraoral and extraoral devices have been utilized to carry out combined maxillomandibular DO using various approaches in the past. Different distraction bases, namely maxillary, mandibular, and temporal, have been utilized for the same purpose using different pivots. These pivots could be contralateral TMJ, pterygomaxillary junction, pyriform, or the artificially placed cinch depending on the osteotomy and placement of distractor., However, the impact of pivots on the outcome of result and stability has been ill defined till date. This study was conducted to evaluate the effect of pterygomaxillary junction, a rigid pivot (in Group II cases where no pterygoid dysjunction was carried out on contralateral, i.e., normal side) with a semirigid osteotomy wire cinch pivot (Group I cases) on the outcome of result. A transoral approach for the ramal osteotomy would have been a better choice rather than the extraoral route which was chosen by the author. However, for the ease of operator and correct definition of distraction vector extra oral route was chosen. Second, an oblique osteotomy was planned in all the cases with intent for correction of deviated midline and to reduce the possibility of a genioplasty for definitive chin correction.
| Conclusion|| |
No significant difference was observed in the study groups suggesting a minimal role of pivots on outcome and stability of such procedure. However, studies with larger sample size and longer follow-up are recommended to reach a definitive conclusion.
The study was carried out at Tertiary Care Dental Centre, and no grant or financial support was received from any source for this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]