Literature search

A comprehensive systematic review of the literature was performed in the bibliographic databases PubMed (National Library of Medicine, NCBI), EMBASE, and the Cochrane Central Register of Controlled Trials from inception to 15 October 2013; the review was performed in accordance with the PRISMA statement. Search terms included controlled terms from medical subject headings (MeSH) in PubMed and Emtree in EMBASE, as well as free text terms. We used free text terms only in The Cochrane Library. Search terms expressing distraction osteogenesis were used in ‘AND’ combination with search terms comprising ‘mandible’ and terms for complication, failure, and morbidity’ ( Table 1 ). The references of the articles identified were searched for additional relevant publications.

Study selection and inclusion criteria

Two reviewers independently screened all potentially relevant titles and abstracts for pre-specified eligibility criteria. If necessary, the full text article was checked for the eligibility criteria. Differences in judgement were resolved through a consensus procedure. Full text articles were then obtained for further review.

Articles were included if they met the following eligibility criteria: (1) clinical article, (2) mandibular distraction osteogenesis (MDO), (3) acquired mandibular deformity, and (4) a report on complications. Exclusion criteria were (1) insufficient data on complications, (2) no available translation, and (3) non-clinical article ( Table 2 ).

The remaining articles, which were clinically relevant to the subject of the study, were included in the systematic review. According to their emphasis, these relevant papers were included if they described MDO in acquired deformities. The articles were screened for the following data: type of deformity, number of patients, type of DO, distraction device, vector, and type and number of complications. The latter were classified according to the proposed classification index shown in Fig. 1 . This classification places emphasis on the severity and clinical consequences of a complication by dividing events according to whether they are spontaneously resolving or permanent complications, and whether hospitalization or general anaesthesia is required for correction of the complication.

Distraction osteogenesis complication index.

The initial literature search yielded a total of 973 references: 521 in PubMed, 437 in EMBASE, and 15 in The Cochrane Library. After removing duplicate references that were selected from more than one database ( n = 329), 644 papers remained. The titles and abstracts were screened for eligibility. Three hundred and twenty-three articles were excluded from the review based on the abstract. The full text was obtained for 321 papers and analyzed further. In total, 216 articles were excluded from the review ( Table 2 ): (1) 130 articles described MDO in patients with non-acquired mandibular deformities; (2) 41 articles had insufficient or no information on complications and/or methods; (3) 17 papers were non-clinical (three scientific, 14 synopsis); (4) four papers had no relevance (three non-DO, one maxilla); (5) 10 papers had no available translation (four Russian, three Chinese, two Hebrew, one Japanese); (6) nine articles had an edited publication type (five discussion, four letters to the editor/authors); and (7) five papers were not available in the international libraries. These seven groups were excluded from further evaluation. In the case of a paper that reported complications in a mixed population (congenital, developmental, and/or acquired), in which the complications could not be traced back to the exact patient subgroup, the article was excluded on the basis of insufficient data. A total of 105 articles met the inclusion criteria and described MDO in acquired deformities. A flowchart of the literature search and selection process through the different phases of the systematic review (PRISMA) is given in Fig. 2 .

Flowchart of the search and selection procedure using PubMed, EMBASE, and The Cochrane Library.