An interventional study of sagittal split osteotomy and Hunsuck Modification of Medial Mandibular Osteotomy in Orthognathic Surgical Procedures, sponsored by Bezmialem Vakif University. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-27.
Sponsored by Bezmialem Vakif University · Not applicable, Interventional, and Treatment
This study aims to compare the effects of the Hunsuck and Posnick modifications of medial mandibular osteotomy on postoperative skeletal stability and relapse in patients undergoing orthognathic surgery. The study will evaluate whether the choice of medial osteotomy technique influences postoperative mandibular relapse.
This study aims to evaluate and compare the effects of two different medial mandibular osteotomy modifications, namely the Hunsuck and Posnick techniques, on postoperative skeletal stability and relapse in patients undergoing orthognathic surgery.
Patients who meet the study eligibility criteria and are scheduled to undergo bilateral sagittal split ramus osteotomy (BSSO) as part of orthognathic surgery will be included. Depending on the medial mandibular osteotomy technique used, patients will be evaluated in two groups: those undergoing the Hunsuck modification and those undergoing the Posnick modification.
Preoperative and postoperative radiographic records will be evaluated to assess skeletal changes associated with each osteotomy technique. Postoperative skeletal stability will be assessed by comparing relevant mandibular and skeletal reference points and angular measurements between the preoperative, immediate postoperative, and follow-up imaging records. The amount and direction of postoperative skeletal relapse will be determined based on changes occurring during the follow-up period.
The primary objective is to determine whether the Hunsuck and Posnick modifications differ in terms of postoperative skeletal stability and relapse following orthognathic surgery. Secondary evaluations may include assessment of the magnitude and direction of mandibular positional changes and comparison of the radiographic outcomes between the two techniques.
The findings of this study may provide clinically relevant information regarding the influence of medial mandibular osteotomy design on postoperative skeletal stability and may help guide the selection of an appropriate osteotomy technique in orthognathic surgery.
Bezmialem Vakif University is the lead sponsor of 354 studies on the registry; 59 are open to participants now.
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Exclusion Criteria:
Patients undergoing orthognathic surgery with bilateral sagittal split ramus osteotomy (BSSO) will undergo medial mandibular osteotomy using the Hunsuck modification. The osteotomy will be performed according to the Hunsuck technique, with the medial horizontal osteotomy terminating at the level of the lingula and extending posteriorly to facilitate the sagittal split. Postoperative skeletal stability and relapse will be evaluated during the follow-up period.
Procedure: sagittal split osteotomy · Procedure: Hunsuck Modification of Medial Mandibular Osteotomy
Patients undergoing orthognathic surgery with bilateral sagittal split ramus osteotomy (BSSO) will undergo medial mandibular osteotomy using the Posnick modification. The osteotomy will be performed according to the Posnick technique, with the modified medial osteotomy design extending posteriorly in accordance with the technique. Postoperative skeletal stability and relapse will be evaluated during the follow-up period.
Procedure: sagittal split osteotomy · Procedure: Posnick Modification Group
Bilateral sagittal split ramus osteotomy will be performed as part of orthognathic surgery to correct the planned mandibular skeletal deformity. The mandibular ramus and body will be divided using the assigned medial osteotomy modification (Hunsuck or Posnick), followed by sagittal splitting of the mandible. The distal mandibular segment will then be repositioned according to the preoperative surgical plan and stabilized using appropriate osteosynthesis. Postoperative skeletal stability and mandibular relapse will be evaluated during the follow-up period.
The Hunsuck modification of the medial mandibular osteotomy will be performed during bilateral sagittal split ramus osteotomy (BSSO). The medial horizontal osteotomy will be initiated at the lingula and extended posteriorly for a short distance, according to the Hunsuck modification. The remaining steps of the BSSO will be performed using the standard surgical technique. Postoperative skeletal stability and relapse will be assessed using preoperative, immediate postoperative, and follow-up radiographic evaluations
The Posnick modification of the medial mandibular osteotomy will be performed during bilateral sagittal split ramus osteotomy (BSSO). The medial horizontal osteotomy will be performed according to the Posnick modification, with the osteotomy design extending posteriorly along the medial aspect of the mandibular ramus as described for this technique. The remaining steps of the BSSO will be performed using the standard surgical technique. Postoperative skeletal stability and relapse will be assessed using preoperative, immediate postoperative, and follow-up radiographic evaluations.
Postoperative Skeletal Relapse
The primary outcome will be the amount and percentage of skeletal relapse between 1 month and 12 months after orthognathic surgery (T3-T1), assessed using three-dimensional cephalometric and skeletal measurements.
Time frame: 1 year
Plan to share: No
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Started Jan 2026 (actual). Primary completion is estimated for Dec 2026, 11 months after the start.
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