Advertisement

The Unfavourable Split: A novel classification and an 11- Year retrospective study looking at alternative methods for management of this well-known complication

Published:November 11, 2022DOI:https://doi.org/10.1016/j.bjoms.2022.11.007

      Abstract

      Objectives

       An unfavourable split is a well-known complication following a sagittal split osteotomy (SSO) of the mandible. Our aim was to analyse all unfavourable mandibular splits that had occurred when carrying out a SSO with the aim to design a classification which can facilitate management.

      Materials and Methods

       We carried out a retrospective study analysing all orthognathic surgery from January 2010 until April 2021. Data surrounding unfavourable splits during this period were specifically analysed. Orthognathic surgery during this period was performed by a single OMFS unit with osteotomies performed by a single surgeon and their trainee. The dataset included 311 patients who underwent either a bilateral sagittal split osteotomy (BSS0) or a bimaxillary osteotomy.

      Results

       There were 225 bimaxillary osteotomies, 86 BSSOs. 21 patients had unfavourable splits following their BSSO with a total of 22 out of 622 sagittal split osteotomies over this 11 year period. Bilateral unfavourable splits occurred in 1 patient. These result correlate to an incidence rate of 6.8% of unfavourable splits following SSO's in an 11-year period.

      Conclusion

       The results reveal common patterns of unfavourable splits. suggest a simple classification based on our results. This can be applied to any unfavourable splits in SSO which then allows the clinician to proceed with surgery and prevent abandonment of the procedure. It is classified as follows:
      Type 1 fractures where the mandibular condyle is attached to the proximal fragment.
      Type 2 fractures whereby the mandibular condyle is attached to the tooth-bearing segment.
      Type 3 fractures are lingual cortex fractures.
      Each of these fracture types has a specific management protocol which we recommend is used in all unfavourable splits.

      Keywords

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to British Journal of Oral and Maxillofacial Surgery
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Dreiseidler T.
        • et al.
        Three-dimensional fracture pattern analysis of the Obwegeser and Dal Pont bilateral sagittal split osteotomy.
        Int. J. Oral Maxillofac. Surg. 2016; 45: 1452-1458
        • Steenen S.A.
        • van Wijk A.J.
        • Becking A.G.
        Bad splits in bilateral sagittal split osteotomy: systematic review and meta-analysis of reported risk factors.
        Int. J. Oral Maxillofac. Surg. 2016; 45: 971-979
        • Obwegeser H.L.
        Zur Operationstechnik bei der Progenie und anderer Unterkieferanomalien.
        Dtsch, Z. Mund. Kieferheilk. 1955; 23: 1-26
        • Obwegeser H.L.
        Orthognathic surgery and a tale of how three procedures came to be: a letter to the next generations of surgeons.
        Clin. Plast. Surg. 2007; 34: 331-355
        • Dal Pont G.
        L’osteotomia retromolare per la correzione della progenia.
        Minerva Chir. 1958; 18: 1138-1141
        • Hunsuck E.E.
        A modified intraoral sagittal splitting technic for correction of mandibular prognathism.
        J Oral Surg. 1968; 26: 49-52
        • Veras R.B.
        • Kriwalsky M.S.
        • Hoffmann S.
        • Maurer P.
        • Schubert J.
        Functional and radiographic long-term results after bad split in orthognathic surgery.
        Int. J. Oral Maxillofac. Surg. 2008; 37: 606-611
        • Hall H.D.
        • McKenna S.J.
        Further refinement and evaluation of intraoral vertical ramus osteotomy.
        J. oral Maxillofac. Surg. 1987; 45: 684-688
        • McKenna S.J.
        • King E.E.
        Intraoral vertical ramus osteotomy procedure and technique.
        Atlas Oral Maxillofac Surg Clin North Am. 2016; 24: 37-43
        • Ellis E.
        A Method to Passively Align the Sagittal Ramus Osteotomy Segments.
        J. Oral Maxillofac. Surg. 2007; 65: 2125-2130