Cleft lip and palate is one of the most common birth defects and can cause difficulties with feeding, speech and hearing, as well as psychosocial problems. Treatment of clefts is lengthy, typically taking from birth to adulthood to complete. Upper jaw growth in cleft patients is highly variable, and in a relatively high percentage, it does not develop completely. A type of surgery called orthognathic surgery, which involves surgical cutting of bone to realign the upper jaw (osteotomy), is usually performed in this situation. An alternative intervention is known as distraction osteogenesis, which achieves bone lengthening by gradual mechanical distraction (cutting of bone and moving the ends apart incrementally to allow new bone to form in the gap).
What was the research?
A systematic review to examine the benefits and risks of distraction osteogenesis for advancing the upper jaw compared to conventional orthognathic surgery in adolescents and adults.
Who conducted the research?
The research was conducted by a team led by Dmitrios Kloukos from the University of Bern, on behalf of Cochrane Oral Health. Piotr Fudalej, Patrick Sequeira-Byron and Christos Katsaros were also on the team.
What evidence was included in the review?
The evidence on which this review is based is up to date as of 16 February 2016. We found six relevant articles to include in this review. All are related to one single randomised controlled trial conducted in Hong Kong. The study involved 47 participants aged 13 to 45 years of age. It investigated the effects of the two surgical procedures on alteration of face morphology, stability of upper jaw after surgery, speech and velopharyngeal function (ability to close the gap between the soft palate and nasal cavity to produce sound), psychological status of the participants and clinical side effects.
What did the evidence say?
Both procedures were effective in producing better facial structure in cleft patients. Upper jaw was more stable in the distraction osteogenesis group than the conventional osteotomy group five years after surgery. There was no difference in speech and velopharyngeal function between the procedures. Social self esteem in the maxillary distraction group initially seemed to be lower than in the conventional surgery group, but this improved over time and the distraction group had higher satisfaction with life two years after surgery. Side effects included deterioration of the fit between the teeth when the mouth is closed and infection of muscous membranes of the nose and mouth, but the frequency of these problems was similar between groups. There was no severe harm to any participant.
How good was the evidence?
The quality of the evidence was judged to be very low. The one study was small and there were concerns about aspects of its design and reporting; therefore we have found no reliable evidence as to which procedure should be regarded superior. High quality clinical trials, which involve lots of people, and different face types, are required to guide decision making.
What are the implications for dentists and the general public?
There is insufficient evidence to support or refute the effectiveness of distraction osteogenesis over orthognathic surgery for cleft patients. While significant inter-individual variation exists, distraction osteogenesis may exhibit less skeletal relapse in the long term. However, there is currently no robust evidence to suggest which treatment modality produces best results. Further prospective research is required to confirm the possible benefits of distraction osteogenesis over orthognathic surgery.
What should researchers look at in the future?
The difficulty encountered with all new and emerging techniques is that whenever an intervention is not supported by high quality evidence, it cannot be inferred that the intervention is ineffective; it can only be concluded that there is inadequate evidence. Only new studies can then contribute to acquiring the evidence needed. On the other hand, the control of multiple variables necessary for new randomised controlled trials makes the designing of new studies difficult. Finally, the strict inclusion criteria and the scarcity of patients with specific characteristics willing to participate in a study make it difficult to achieve a proper sample size.
Kloukos D, Fudalej P, Sequeira-Byron P, Katsaros C. Maxillary distraction osteogenesis versus orthognathic surgery for cleft lip and palate patients. Cochrane Database of Systematic Reviews 2016, Issue 9. Art. No.: CD010403. DOI: 10.1002/14651858.CD010403.pub2.