Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns

Abstract

An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a ‘bad split’. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A–F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches.

Segmenting the mandible in an orthognathic procedure to reposition the tooth-bearing part is generally known as a bilateral sagittal split osteotomy (BSSO). Historically, different ways of splitting the mandible have been advocated. The Trauner and Obwegeser technique (1955), the Dal Pont modification (1961), and the Hunsuck modification (1968) are the best documented. Various approaches, splitting techniques, and instruments have been advocated to reduce complications over the years since Hugo Obwegeser reported the operation in 1955. Despite these improvements, the procedure remains technically challenging in some cases. Intraoperative complications include nerve injury, bleeding, and mechanical problems, such as irregular split patterns. An unfavourable and unanticipated pattern of the mandibular osteotomy fracture is generally referred to as a ‘bad split’. Incidences of 0.2% up to 14.6% per split site have been reported.

Bad splits may cause mechanical instability, a disturbance in bony union, and lead to bone sequestration with subsequent infection. In addition, it has been proposed that temporomandibular joint (TMJ) dysfunction and inferior alveolar nerve damage may arise due to excessive intraoperative manipulation in an attempt to reposition the fractured segments, and that subsequent difficulty in positioning the condyle in the glenoid fossa may increase the risk of relapse. In order to reduce the risk of postoperative functional deficits, fractured split segments are best fixated and reconsolidated. However, few restorative techniques to manage the situation have been described.

The aim of this article is to review unfavourable split pattern types reported in the literature, and to present appropriate salvage procedures to manage the different types of undesired fracture.

Materials and methods

Systematic review

A systematic review was undertaken, which is reported in accordance with the PRISMA Statement.

Eligibility criteria

All retrospective and prospective studies of unwanted splits in BSSO procedures, with or without control groups, were included. There were no restrictions.

Information sources and search

An electronic search without date or language restrictions was undertaken on 12 August 2015, in the online databases PubMed (all indexed years), Web of Science (Science Citation Index Expanded; 1975 to present (v. 5.13.1)), the Cochrane Central Register of Controlled Trials, and the World Health Organization International Clinical Trials Registry Platform, using the strategy outlined in Table 1 .

Table 1
Search terms.
Database Search terms
PubMed (all indexed years) (orthogn* OR (sagittal AND (ramus OR split))) AND (bad OR unfavo* OR undesired OR unwanted OR unexpect* OR complic* OR irregular)
Web of Science, Science Citation Index Expanded 1975 to present (v.5.13.1) #1: TS = (sagittal AND osteotomy)
#2: WC = (Dentistry, Oral Surgery & Medicine)
#3: #1 AND #2
Cochrane Central Register of Controlled Trials Sagittal osteotomy
WHO International Clinical Trials Registry Platform Split osteotomy OR ramus osteotomy [Recruitment status: ALL]

Trial selection

After assessing the eligibility of the articles in a standardized manner by reading the titles and abstracts, selected articles were retrieved and the full-texts read to screen for eligibility.

Data extraction and collection

A data extraction sheet was developed. For each of the articles identified and included in this study, the following data were extracted: (1) author and year of publication, (2) study design, (3) surgical technique, (4) number of patients who underwent BSSO, (5) number of patients who underwent concomitant third molar removal, (6) number of patients who had no third molars present at surgery, (7) patient age statistics, (8) number of split sites, number of bad splits, and the unwanted split pattern types per patient and per split site. Summary outcome data were entered into Review Manager software (RevMan version 5.2; Cochrane Collaboration, 2012).

The development of the search strategy, study selection, and data collection were performed by one author (SAS).

Results

The initial search yielded a total of 2062 citations ( Fig. 1 ). After the primary screening process, 33 full-text reports were read for detailed examination. No articles needed to be excluded after secondary review. The eligibility criteria were met by a total of 33 reports; these included 15 retrospective chart reviews, nine retrospective cohort studies, six prospective cohort studies, one cross-sectional study, one matched-pair analysis, and one case report ( Table 2 ).

Fig. 1
Flow of information through the different stages of the systematic search.

Table 2
Reported incidence and patterns of bad splits during sagittal split osteotomy procedures (1971–2015).
Author Study design Technique No. of patients Patient age, mean/median and range (years) No. of splits Bad split occurrence Incidence per patient (%) Incidence per split side (%) Bad split types specified
Type 1 Proximal Type 2 Distal Type 3 Coronoid Type 4 Condylar
Guernsey and DeChamplain 1971 Retrospective chart review Obwegeser 22 21.9 (15–32) 44 5 22.7% 11.4% 2 3
(1 greenstick fracture)
0 0
Behrman 1972 Cross-sectional survey Obwegeser ∼600
(10/64 surgeons reported having ever had a bad split)
Jönsson et al., 1979 Prospective cohort study Dal Pont modification 28 56 5 17.9% 8.9% 5
(2 type 1B/1C and 3 type 1D)
0 0 0
MacIntosh 1981 Retrospective chart review Dal Pont modification 236 25 (13–53) 472 16 6.8% 3.4%
(type 1C/1D/1A/1F)

(type 2B)
Martis 1984 Retrospective chart review Dal Pont modification 258 20 (14–40) 516 5 1.9% 1.0% 4 1 0 0
Turvey 1985 Retrospective cohort study Dal Pont modification 128 25.7 (6–56) 256 9 7.0% 3.5% 8 1
Van Merkesteyn et al., 1987 Retrospective chart review Obwegeser (1)/Dal Pont modification (62) 63 25.1 (15–59) 126 5 7.9% 4.0% 5
(type 1D)
0 0 0
Mommaerts 1992 Case reports Obwegeser 96 17, 25 192 2 2.1% 1.0% 1
(type 1D)
1
Tucker and Wolford 1995 Retrospective chart review 207 400 21 10.1% 5.3%
Van de Perre et al., 1996 Retrospective chart review Dal Pont modification and Hunsuck modification 1233 2466 97 7.9% 3.9% “the majority”
Precious et al., 1998 Retrospective cohort study Duguet (Duguet et al., 1987) (group 1: M3 present; group 2: M3 removed >6 months preop.) 633 24.4 (12–57) 1256
(532 in group 1; 724 in group 2)
24
(5 in group 1; 19 in group 2)
3.8% 1.9% 15
(type 1B/1C)
9 0 0
Akhtar and Tuinzing 1999 Retrospective chart review Hunsuck modification 2820 6 0.2%
Acebal-Bianco et al., 2000 Retrospective chart review Dal Pont–Hunsuck–Simpson–Epker modification (Epker 1977; Simpson 1972) 802 23 (13–73) 1584 8 1.0% 0.5% 6 1 1 0
Maurer et al., 2001 Retrospective chart review Dal Pont modification 336 672 34 10.1% 5.1%
Mehra et al., 2001 Retrospective cohort study Wolford (Wolford et al., 1987; Wolford and Davis 1990) (group 1: concomitant M3 removal; group 2: M3 removed >12 months preop.) 262
(137 in group 1; 125 in group 2)
17.7 (13–44) in group 1
36.6 (17–56) in group 2
500
(250 in group 1; 250 in group 2)
11 (8 in group 1; 3 in group 2) 4.2% 2.2% 1
(group 1; type 1C)
3
(group 2; type 1C)
7
(group 1; type 2A)
0 0
Panula et al., 2001 Retrospective chart review 515 30.3 (15–60) 1030 12 2.3% 1.2%
Reyneke et al., 2002 Prospective cohort study 70 23.3 (13–49) 139 5 7.1% 3.6% 1 4 0 0
Borstlap et al., 2004 Prospective cohort study Hunsuck modification
(group 1: concomitant M3 removal; group 2: M3 not present at surgery)
222 25.2 (13–53) 444
(123 in group 1; 321 in group 2)
20
(8 in group 1; 12 in group 2)
9.0% 4.5% 0
(group 1)
8
(group 2)
8
(group 1)
4
(group 2)
0 0
Teltzrow et al., 2005 Retrospective chart review Obwegeser 1264 14–53 12 0.9% 6 1 3 2
Kim and Park 2007 Retrospective chart review 238 474 11 4.6% 2.3%
Kriwalsky et al., 2008 Retrospective cohort study Dal Pont modification
(group 1: M3 removed >12 months preop.; group 2: M3 concomitantly removed; group 3: M3 present at surgery and left in place)
110 26 (17–60) in group 1
22 (17–39) in group 2
26 (17–60) in group 3
(35.0 (21–60) in the bad split group; 24.6 (17–46) in the regular split group)
220
(168 in group 1; 23 in group 2; 29 in group 3)
12
(9 in group 1; 2 in group 2; 1 in group 3)
10.9% 5.5%
Veras et al., 2008 Matched-pair analysis Dal Pont modification Selection of patients from Kriwalsky et al., 2008 30.7 (22–43) 6 1
Falter et al., 2010 Retrospective chart review Epker modification (Epker 1977) 1008 33.1 (21–61) in the bad split group
25.9 (16–61) in the regular split group
2005 14 1.4% 0.7% 13 1 0 0
Doucet et al., 2012 Prospective cohort study Duguet (Duguet et al., 1987)
(group 1: concomitant M3 removal; group 2: M3 removed >6 months preop.)
60 19.3 in group 1
24.9 in group 2
120
(64 in group 1; 56 in group 2)
4
(2 in group 1; 2 in group 2)
6.7% 3.3% 0 4 0 0
Gilles et al., 2013 Prospective cohort study Piezotome surgery
Hunsuck modification
54 102 0 0.0% 0.0%
Mensink et al., 2013 Retrospective chart review Hunsuck modification 427 29 (15–54) 851 17 4.0% 2.0% 11
(1C/1E)
5 0 1
Aarabi et al., 2014 Retrospective cohort study Epker modification (Epker 1977) 48 21.8 in the group with bad splits
26.6 in the group without bad splits
96 14 29.2% 14.6%
Al-Nawas et al., 2014 Retrospective cohort study Group A: Epker modification (Epker 1977)
Group B: Dal Pont modification
400
(214 in group A; 186 in group B)
26.5 (14–68) 800 43
(16 in group A; 27 in group B)
10.8% 5.4%
Verweij et al., 2014 Retrospective cohort study Hunsuck modification
(group 1: concomitant M3 removal; group 2: M3 removed >6 months preop.)
259 27.7 (13–55) 502
(169 in group 1; 333 in group 2)
10
(5 in group 1; 5 in group 2)
3.9% 2.0%
Balaji 2014 Retrospective chart review 208 21.53 (17–27) 416 27
(25 greenstick fractures)
13.0% 6.5% 0 27 0 0
Landes et al., 2014 Retrospective cohort study Piezotome surgery
Landes modification (Landes et al., 2008)
29 26.5 58 4 13.8% 6.9%
Politis et al., 2014 Prospective cohort study Group A: Epker modification (Epker 1977)
Group B: own technique
353
(220 in group A; 133 in group B)
706
(440 in group A; 266 in group B)
2
(0 in group A; 2 in group B)
0.6% 0.3%
Camargo et al., 2015 Retrospective cohort study Jeter modification (Jeter et al., 1984)
(group 1: concomitant M3 removal; group 2: M3 removed earlier)
102
(10 in group 1; 92 in group 2)
41 (30–68) 204 3
(1 in group 1; 2 in group 2)
2.9% 1.5% 1
(group 1)
1
(group 2)
1
(group 1)
1
(group 2)
0 0
Total 10,271 19,527 458 4.5% overall 2.3% overall 97 79 4 4
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Jan 16, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns
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