Abstract
The aim was to systematically review the maxillary incisor exposure and upper lip position changes with Le Fort I type osteotomies for advancement ± impaction with rigid internal fixation, taking into account the use of cinch sutures and VY closures. Electronic databases (Cochrane Library, Medline, Embase, and Web of Science) were searched using medical subject headings (MeSH), key words, truncations, and Boolean operators. Hand searching was also undertaken. Of 979 articles identified, 15 were included (11 retrospective, two prospective, and two unspecified). Relevant study details and outcomes were recorded on a spreadsheet, along with an assessment of their quality. In total, these studies assessed 419 patients (266 female, 118 male) with a mean age of 26.4 years (range 14–57 years). Soft tissue changes were assessed on lateral cephalometric radiographs. The mean maxillary hard tissue advancement and impaction ranged between 0.94 and 8.77 mm and −0.56 and 4.2 mm, respectively. The ranges of ratios demonstrated that from pronasale (0.24–0.35) to labrale superius (0.36–1.43), the soft tissues followed the underlying horizontal hard tissue movement increasingly more closely. Alar base cinch sutures and VY closures tended to increase these ratios. The soft tissue response was more variable vertically. None of the studies reported on maxillary incisor exposure change. More good quality prospective studies are needed.
Systematic reviews allow condensation of available research on a specific topic and analysis of both the quality of research being undertaken and the outcomes of the studies themselves. The latter can be merged in a meta-analysis, provided the studies are homogeneous with regards to sample characteristics, interventions, follow-up protocols, and outcome measures. In addition, it may highlight what further research would be helpful. Previous systematic reviews in the field of orthognathic surgery have focused on the accuracy of computer programs in predicting hard and soft tissue responses to orthognathic surgery, the soft tissue changes following anterior segmental surgeries, bilateral sagittal split osteotomy (BSSO) for mandibular setback, and the effects on speech. However, no systematic review has been undertaken to assess the maxillary incisor exposure change and soft tissue response to Le Fort I type maxillary osteotomies for advancement ± impaction taking into account the effect of alar base cinch sutures and VY closures.
Contemporary orthognathic surgical planning revolves around the position of the maxillary incisors in relation to the soft tissue envelope of the face and lips to achieve ideal facial aesthetic and dental occlusal outcomes. The dynamic relationship of the maxillary incisor exposure on smiling is also an important aesthetic parameter. Therefore, predicting the effect of different surgical movements on soft tissues and the effect of these on the incisor exposure is the key to planning the case. When using computer software or undertaking hand prediction tracings, the soft tissue changes are predicted by using the hard to soft tissue ratios calculated by previous studies. In a systematic review, Kaipatur and Flores-Mir found that although the individual errors were minimal (less than 2 mm) between the prediction and the actual measurement, the amalgamation of these minimal errors could have clinical implications.
Therefore, it would be interesting to identify which variables have been accounted for in the research that has developed these ratios, and potentially which variables might be limiting the accuracy of the predictions and could be borne in mind in future research to improve the planning and prediction of surgical outcomes, e.g. if alar base cinch sutures and VY closures have an effect on the soft tissue response.
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used in this review. The aim was to systematically review the literature on the change in maxillary incisor exposure (repose and smiling) and soft tissues (especially the upper lip) after a Le Fort I type maxillary osteotomy for advancement ± impaction with rigid internal fixation, with or without a mandibular procedure.
The specific questions to be answered were:
- (1)
What is the relationship between the maxillary incisor exposure change (in repose and on smiling) and the skeletal movement in maxillary Le Fort I type osteotomies for advancement ± impaction?
- (2)
What is the relationship between the soft tissue changes (particularly the upper lip) and skeletal movement in maxillary Le Fort I type osteotomies for advancement ± impaction?
- (3)
Is there an effect on the above results if additional surgical techniques such as alar base cinch suture, V–Y closure, or anterior nasal spine recontouring are undertaken?
Materials and method
The following electronic databases were searched in September 2011: Cochrane Library (Issue 9 of 12, September 2011), EMBASE (1980 to week 35 of 2011), Medline (1948 to week 4 of 2011), and Web of Science (Science Citation Index Expanded 1899 to present and Conference Proceedings Citation Index 1990 to present).
The key words used were: upper, maxilla* surgery, maxilla* advancement, maxilla* impaction, orthognathic surgery, Le Fort I, osteotomy, teeth OR tooth OR incisor*, lip OR lips, and the combination of the above terms using “AND”. Medical subject heading (MeSH) terms such as osteotomy, lip, and incisor were also used and all their trees exploded. The search was devised for Medline and EMBASE and revised appropriately to suit Science Direct and PubMed, where a combination of free text terms with Boolean operators and truncations were employed. An example of the search and combinations carried out in Cochrane is attached as Appendix 1 . No limitations were used regarding language or publication type.
In addition, hand searching included retrieving relevant articles mentioned in the reference lists of identified articles and reading special editions dedicated to orthognathic surgery in well known journals in maxillofacial surgery and orthodontics. Duplicates were discarded.
The inclusion criteria for the selection of studies were the following: (1) Retrospective or prospective clinical studies with human subjects including randomized controlled trials, case controlled studies, and case series. (2) Patients who had undergone orthognathic surgery to the maxilla (Le Fort I impaction and/or advancement), excluding those where it was stated that circumferential wires and/or intermaxillary fixation (IMF) had been used postoperatively. Ideally, the use of rigid internal fixation should have been stated. (3) If adjunctive techniques such as alar base cinch suture (AB), V–Y closure of incision (VY), or anterior nasal spine (ANS) remodelling were used, the number of patients who received this should ideally be specified and their results analyzed separately. (4) Participant characteristics should be specified: age, gender breakdown. (5) Length of follow-up should be at least 3 months to allow for soft tissue swelling to settle. (6) Outcomes should be stated in terms of the changes in amount of maxillary incisor exposure after the surgery and/or soft and hard tissue changes related to the change in upper lip position. (7) Outcomes could be measured on lateral cephalometric radiographs, clinically (if direct measurements were taken with callipers), or from other sources such as photographs or laser scanning images.
Case reports, technical notes, opinions, editorials, oral presentations, review articles, and studies involving animal models or patients with clefts, trauma, or syndromes were excluded. If the same data from a study were reported in two different articles, only one of the articles was included. The reason for including only rigid maxillary fixation was to reduce the variables and aim the review at the current practice of fixation in orthognathic surgery. However a comparison to some papers using other fixation methods will be discussed.
An initial screening was undertaken based on titles and abstracts, following which full text articles were retrieved and reviewed for those that appeared to fulfil the inclusion criteria and for those for which more details were necessary prior to a decision. The article selection, data extraction, and quality appraisal were performed by LKL with discussions with FBN to solve doubts.
The data retrieved from the selected studies included: sample size and characteristics (age, gender breakdown, ethnicity, and malocclusion), study design, surgical treatment details (including the use of adjunctive procedures such as alar base cinch sutures, VY closures, or ANS recontouring), and outcome measures (type of imaging, timing, and actual measurements). The outcome measures had to include a measurement related to maxillary incisor exposure change and/or changes in the soft tissues of the upper lip. Data were collated on an Excel spreadsheet. The risk of bias of the studies included was assessed using a quality assessment checklist ( Fig. 1 ), which has been described in a previous systematic review.
Results
In total, 979 articles were identified, of which 47 full length articles were reviewed; 15 were identified as meeting the inclusion criteria. The PRISMA flowchart showing the number of articles remaining at each stage of the sequence of identification, screening, and final inclusion is illustrated in Fig. 2 .
Of the 47 full length articles reviewed, 32 were excluded. The reasons for exclusion included: outcome measures not providing the information relevant to this systematic review ( n = 20), maxillary surgery not being part of the treatment patients received ( n = 5), intermaxillary fixation or circum-maxillary wires used ( n = 5), and type of publication ( n = 2).
Study characteristics
The 15 studies included were published in the years ranging from 1992 to 2011. Countries from which two or more articles were included were: USA ( n = 4), Turkey ( n = 3), and UK ( n = 2). The study designs were most commonly retrospective ( n = 11). There were only two prospective trials and two did not specify this, just reporting that the patients included were consecutive ( Table 1 ).
| No. | Study | Year | Country | Journal | Study design |
|---|---|---|---|---|---|
| 1 | McCollum et al. | 2009 | South Africa | Seminars in Orthodontics | R |
| 2 | Chew | 2005 | Singapore | Angle Orthodontist | R |
| 3 | Conley and Boyd | 2007 | USA | Journal of Oral and Maxillofacial Surgery | R |
| 4 | Enacar et al. | 1999 | Turkey | International Journal of Adult Orthodontics and Orthognathic Surgery | R |
| 5 | Altug-Atac et al. | 2008 | Turkey | Angle Orthodontist | R |
| 6 | Muradin et al. | 2011 | The Netherlands | Journal of Oral and Maxillofacial Surgery | P, CT |
| 7 | Louis et al. | 2001 | UK | Journal of Oral and Maxillofacial Surgery | R |
| 8 | Peled et al. | 2004 | Israel | Journal of Oral and Maxillofacial Surgery | P |
| 9 | Shoji et al. | 2011 | Japan | British Journal of Oral and Maxillofacial Surgery | NR; Cons. |
| 10 | Coleta et al. | 2009 | Brazil and USA | International Journal of Oral and Maxillofacial Surgery | R |
| 11 | Jensen et al. | 1992 | USA | American Journal of Orthodontics and Dentofacial Orthopedics | R |
| 12 | Baik and Kim | 2010 | Korea | American Journal of Orthodontics and Dentofacial Orthopedics | NR |
| 13 | Marçan et al. | 2009 | Turkey | Journal of Cranio-Maxillofacial Surgery | R |
| 14 | Talebzadeh and Pogrel | 2000 | USA | Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontics | R |
| 15 | Lin and Kerr | 1998 | UK | European Journal of Orthodontics | R |
A summary of the demographic data relating to the samples of the studies and details of the interventions is provided in Table 2 . In total the studies assessed the outcomes of 419 patients, of whom 266 (63%) were females and 118 (28%) were males; gender was unreported for 35 (8%). From the reported data, the mean age was 26.4 years (range 14–57 years). The sample’s ethnicity was reported in only four studies and included Chinese, Japanese, Korean, and Turkish. The malocclusion of the patients in the studies included was mostly Class III. Bimaxillary surgery was provided in most studies ( n = 14), with only Peled et al. reporting data on isolated maxillary Le Fort I type advancement and impaction osteotomies. The bimaxillary surgery involved a Le Fort I type osteotomy for advancement ± impaction and mandibular BSSO, except for two studies where vertical ramus osteotomies were used instead, in all or some of the patients. The mandibular movement varied from setback (eight studies) to advancement (five studies). Additional procedures such as genioplasty were performed in some or all patients in five studies. Surgical techniques such as ANS recontouring, alar base cinch suture, and V–Y closure of the incision were used by different authors in varied combinations, in some cases comparing a group receiving one of these techniques to a group receiving simple continuous suturing (SCS) of the incision. The use of rigid internal fixation for stabilization was specified in nine studies (60%). Only in seven studies (47%) was the number of surgeons who had treated the patients stated (ranging from 1 to 10 surgeons).
| Study | Sample size (F:M) | Mean age years (range or SD) | Ethnicity | Malocclusion | Presurgical orthodontics | Number of surgeons | Type of surgery and subgroups ( n ) | Fixation | ANS, VY, AB, mACVY, SCS ( n ) |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 26 (16:10) | F: 25 (16–38) M: 22.1 (18–29) |
NR | Class III | Y | 10 | Le Fort I advancement with minimal impaction: and mandibular setback (6), reduction genio (4), both (3) | NR | ANS (26), VY (11) |
| 2 | 34 (20:14) | 22.1 (6.2) | Chinese | Class III | Y | NR | Bimax: Le Fort I and BSSO advancement | RIF | None |
| 3 | 31 (4:27) | 45 (8.1), range 27–59 | NR | NR | N (except for 3) | 1 | Bimax: Le Fort I and BSSO advancement G1: genio (NR), G2: no genio (NR) |
RIF | ANS (31), AB (31), VY (31) |
| 4 | 12 (7:5) | 22.5 ± 2.3 years | NR | Class III | Y | NR | Bimax (12): Le Fort I advancement and BSSO setback Single jaw (12): BSSO setback |
NR | None |
| 5 | 20 (11:9) | 21.3 (17.08–30.08) | NR | Class III | Y | NR | Bimax: Le Fort I advancement (no impaction) and BSSO setback | NR | None |
| 6 | 56 (35:21) SCS (17:8) mACVY (18:13) |
26.9 (15.4–47.9) SCS: 26.3 ± 8.8 mACVY: 25.8 ± 9.3 |
NR | NR | Y | NR | Bimax: Le Fort I impaction ± advancement and mandibular advancement (18) or setback (13), of which SCS (5) and mACVY (8) | RIF | mACVY (31), SCS (25) |
| 7 | 15 (NR) | NR | NR | NR | N | NR | Bimax: Le Fort I advancement (8 ± 2.5 mm) with minimal impaction (<3.5 mm) and BSSO and geniotomy advancement | RIF | VY (15) (none AB or ANS) |
| 8 | 35 (17:18) | 19.06 (17–28) | NR | NR | Y | NR | Le Fort I advancement (3–6 mm) and ≤3 mm vertical movement | RIF | AB (35); random assign to: VY (17), SCS (18) |
| 9 | 30 (26:4) | 22 (17–36) | Japanese | Class III | Y | 1 | Bimax: Le Fort I advancement or rotation and BSSO setback | NR | AB (30), VY (30), ANS (when maxilla advanced) |
| 10 | 44 (44:0) | 34.5 (14–57) | NR | Class III | NR | 1 | TMJ replacement (TMJ Concepts total joint prosthesis) and maxillary advancement and impaction anteriorly and mandibular counterclockwise advancement and augmentation genio (18), no genio (26) | RIF | AB (44), VY (44) |
| 11 | 17 (15:2) | 30. 75 | NR | Class II | NR | 1 | Bimax: Le Fort I impaction with Wolford step and BSSO advancement | RIF | AB (17), VY (17) |
| 12 | 20 (NR) | ≥18 | Korean | Class III | NR | AB cinch by 1 | Bimax: Le Fort I advancement (1–3 mm), posterior impaction (1–3 mm) and setback bilateral intra-oral VRO; genio (10), no genio (10) | NR | AB (20), VY (20), ANS (20) |
| 13 | 44 (44:0) | 28.3 ± 3.7 | Turkish | Class III | Y | NR | Bimax: Le Fort I advancement and impaction and BSSO setback | RIF | None |
| 14 | 18 (11:7) | NR | NR | NR | NR | 3 | Bimax: Le Fort I advancement and impaction and BSSO setback | RIF | VY (10), SCS (8) |
| 15 | 17 (16:1) | 24 ± 8 | NR | Class III | Y | NR | Bimax: Le Fort I advancement and mandibular setback by BSSO or VRO | NR | NR |
Lateral cephalometric radiographs were taken preoperatively (within 8 weeks to immediately preoperatively) and postoperatively (3–40.8 months) to assess soft tissue changes ( Table 3 ). Four studies did not report the timing of the preoperative radiograph and all but one study used lateral cephalometric radiographs, which were taken at least 6 months postoperatively. The soft and hard tissue changes were most commonly assessed on these radiographs (eight studies) by tracing a line 6–12° from the sella–nasion line (SN) to produce a horizontal reference line ( x -axis) and a perpendicular to this through either sella or nasion, to produce the vertical reference line ( y -axis). Other methods included using the Frankfort horizontal (FH) line, SN line, or natural head position to produce the horizontal reference line. In addition to the radiographic examinations, clinical measurements with a sliding digital calliper and surface facial laser scans were also undertaken.
| Study | Imaging type | Timing: pre-op | Timing: post-op (range) | Tracing method | Reference lines |
|---|---|---|---|---|---|
| 1 | Lateral cephalogram | 4 weeks | 7 months (3–16) | H | x : 6° to SN y : perpendicular to above at S |
| 2 | Lateral cephalogram | Within 8 weeks | At least 6 months (6.2–22) | D | x : 7° to SN y : perpendicular to above at N |
| 3 | Lateral cephalogram | Within 4 weeks | At least 6 months | H and D | x : operator assisted natural head position |
| 4 | Lateral cephalogram | Within 4 weeks | 12 months | H | Ricketts’ cephalometric reference planes (PTV, FH, E-plane) |
| 5 | Lateral cephalogram | Pre-treatment and 2–4 days before | At least 10 months | H and D | x : SN y : perpendicular to above at S |
| 6 | Lateral cephalogram | NR | At least 12 months | D | x : 7° to SN y : perpendicular to above at S |
| 7 | Lateral cephalogram | NR | At least 8 months (8–24) | H | Transparent grid with xy coordinates marked in mm used to measure changes |
| 8 | Lateral cephalogram | NR | At least 6 months | NR | NR |
| 9 | Lateral cephalogram, clinical a | Both: 1 week pre-op | Both: 1 week and 12 months | NR | x : FH y : perpendicular to above at N |
| 10 | Lateral cephalogram | 1–6 days pre-op | 40.8 months (12–143) | D | x : 7° to SN y : perpendicular to above at S |
| 11 | Lateral cephalogram | Within 1 week | At least 9 months | D | x : 12° to SN y : perpendicular to above at S |
| 12 | Lateral cephalogram, laser scans | Laser scan: 1 month pre-op Cephalogram: NR |
Laser scan: at least 6 months Cephalogram: NR |
NR | x : 7° to SN y : perpendicular to above at S |
| 13 | Lateral cephalogram | Immediately pre-op | 2.6 ± 0.7 years | H | x : 7° to SN y : perpendicular to above at N |
| 14 | Lateral cephalogram | Up to 2 weeks | 12 months | H | Linear measurements only |
| 15 | Lateral cephalogram | When presurgical orthodontics completed | 3–6 months | D | x : 7° to SN y : perpendicular to above at S |
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