The Cleft Palate–Craniofacial Journal 51(6) pp. 651–657 November 2014 Ó Copyright 2014 American Cleft Palate–Craniofacial Association
ORIGINAL ARTICLE Evaluation of Transverse Maxillary Expansion After a Segmental Posterior Subapical Maxillary Osteotomy in Cleft Lip and Palate Patients With Severe Collapse of the Lateral Maxillary Segments S. Carpentier, D.D.S., J. van Gastel, D.D.S, Ph.D., J. Schoenaers, M.D., D.D.S., Ph.D., C. Carels, D.D.S., Ph.D., V. Vander Poorten, M.D., Ph.D., W. Coucke, M.Stat., Ph.D., A. Verdonck, D.D.S., Ph.D. Objective: The purpose of this longitudinal retrospective study was to evaluate transverse maxillary expansion after a Schuchardt or segmental posterior subapical maxillary osteotomy (SPSMO) in patients with cleft lip and palate (CLP). A second aim was to compare these data with data for adult patients without CLP who were receiving a surgical assisted rapid palatal expansion (SARPE). Method: The study group comprised 19 patients with CLP and a severe transversally collapsed maxilla who were treated with SPSMO followed by hyrax expansion at the University Hospitals Leuven. Dental casts of the 19 patients were analyzed before treatment, at maximum expansion, during orthodontic treatment, at the completion of orthodontic treatment. and 2 years after orthodontic treatment and were measured at the canine, premolar, and molar levels. Adult patients without CLP who were enrolled in a prospective study served as the control group. Results: Maxillary expansion within the study group was significantly greater (P , .05) at all measured levels compared with the maxillary arch before treatment. No significant relapse was measured in the study group 2 years after orthodontic treatment. When comparing the study and control groups, the only statistical difference was that canine expansion was significantly greater in the study group. Conclusion: SPSMO followed by maxillary expansion and orthodontic treatment is an appropriate treatment option to correct a severe transversally collapsed maxilla in patients with CLP. The overall treatment effect of SPSMO expansion is comparable with the effects of SARPE, although canine expansion was greater in the SPSMO group. KEY WORDS: cleft lip and palate, maxillary expansion, segmental posterior subapical maxillary osteotomy, transversal maxillary width
Most patients with cleft lip and palate (CLP) present transverse maxillary deficiency. Clinically, this can be seen as a unilateral or bilateral crossbite. A review of the literature suggests that the growth of the maxillary dental arch in patients with CLP is inhibited owing to congenital developmental deficiency, palatal muscle strain, scar retraction, and a history of surgical treatment (Yang et al., 2012). Ye et al. (2010) found that the major cause of maxillary dental arch constriction was scar tissue distribution on the palate. In the initial healing phase, transverse growth of the alveolar bone in patients with CLP is affected by wound contraction and the contractile force exerted by myofibroblasts in granulation tissue. The scar tissue that subsequently forms on denuded bone might impair the maxillary alveolar growth long term (Kim et al., 2002). The purpose of the present study was to evaluate transverse maxillary expansion after a Schuchardt osteotomy or segmental posterior subapical maxillary osteotomy (SPSMO) in patients with CLP and a severe transversally collapsed maxilla. The SPSMO was performed to create a paramedian osteotomy site within healthy maxillary bone.
Dr. Carpentier is a postgraduate student in orthodontics, Katholieke Universiteit Leuven, Leuven, Belgium. Dr. van Gastel is a member of the clinical staff, Orthodontic Department, Katholieke Universiteit Leuven, Leuven, Belgium. Dr. Verdonck is Professor of Orthodontics, Department of Oral Health Sciences, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium. Dr. Carels is Professor of Orthodontics, Department of Oral Health Sciences, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium. Dr. Schoenaers is Professor of Stomatology and Maxillofacial Surgery, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium; Dr. Vander Poorten is Professor of Otorhinolaryngology and Head and Neck Surgery, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium. Dr. Coucke is Statistician, Department of Quality of Medical Laboratories, Scientific Institute of Public Health, Brussels, Belgium. Submitted September 2013; Revised January 2014; Accepted March 2014. Address correspondence to: Prof. Dr. A. Verdonck, Department of Oral Health Sciences - Orthodontics, Katholieke Universiteit Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium. DOI: 10.1597/113-232 651
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TABLE 1
Standard Treatment Protocol at CLPT-UHL Procedure
Timing
Alveolar molding in selected patients Lip closure; two-stage procedure in patients with BCLP Soft palate closure Maxillary expansion with a removable appliance when the small segment has collapsed Hard palate closure Maxillary expansion with a removable appliance when the small segment has collapsed Secondary alveolar bone grafting SPSMO in selected patients who still have a severe collapsed maxilla with crossbite Orthodontic treatment Follow-up
A second aim was to compare these data with the data for adult patients without CLP (Chamberland et al., 2011) who were receiving a surgical assisted rapid palatal expansion (SARPE). MATERIAL
AND
METHODS
About 450 patients with CLP attend an annual multidisciplinary consultation with the cleft lip and palate team of the University Hospitals Leuven (CLPT-UHL) until they reach the age of 20. The standard treatment protocol at CLPT-UHL, which is always adapted to the individual needs of the patient, is demonstrated in Table 1. From the patient population with CLP consulting the CLPT-UHL between May 1996 and November 2009, 31 nonsyndromic patients with CLP showed a severe transversally collapsed maxilla. Only 19 of them were included in this longitudinal retrospective study, which was approved by the clinical trial center (ethics review committee) at University Hospitals Leuven (Table 2A). The other 12 patients with CLP were excluded because of lack of sufficient data. All 19 patients, 4 girls and 15 boys (mean age, 14.0 6 2.6 years), were nonsyndromic patients with CLP who were white, had no major medical history, and had a comparable social background. All patients presented a transversally constricted maxilla, which is defined as a maxillary intercanine width less than 33 6 2 mm at the age of 14 (Moorees, 1959). They were treated according to the CLPT-UHL protocol and received an SPSMO, which was performed by the same experienced surgeon and was followed by a maxillary expansion through a toothborne hyrax and orthodontic intervention. The following types of TABLE 2A
Before lip closure 3 months 1 year Before hard palate closure 5–6 years Before alveolar bone grafting When 2/3 of the root of the maxillary canine has formed After consolidation of alveolar bone graft and eruption of the canine Permanent dentition Lifetime
clefts were seen in the study group (Table 2A): three patients with cleft palate (CP), one patient with right unilateral cleft CLP (RUCLP), 11 patients with left unilateral CLP (LUCLP), and four patients with bilateral CLP (BCLP). Dental casts of the patients enrolled in this study were analyzed immediately before SPSMO (T1, n ¼ 19), at completion of maxillary expansion (T2, n ¼ 13), during orthodontic treatment (T3, n ¼ 13), at the completion of orthodontic treatment (T4, n ¼ 19), and 2 years after orthodontic treatment (T5, n ¼ 13) (Table 2A). Changes in tooth positions and maxillary width were evaluated by measurements on the available dental casts at each time point, T1 to T5, using a caliper (Mitutyo Asia Pacific Ltd., Singapore) with a precision of 0.5 mm). Intercanine width was measured at the cusp tip, inter-premolar width was measured in the mesial fossa of the first premolar, and intermolar width was measured in the central fossa of the first molar. All measurements were performed twice, at a 2week interval, by two independent observers. The SPSMO was originally described by Schuchardt in 1959 as a two-stage procedure for correcting open bite deformities. It is now also used as part of the treatment protocol at the CLPT-UHL in patients with CLP presenting a severe transversally collapsed maxilla. The SPSMO procedure is performed in the permanent dentition after consolidation of the secondary alveolar bone graft procedure and eruption of the cuspid. Dental age of the patient with CLP is very important because the maxillary canine and the second molar have to be erupted to perform the SPSMO. The SPSMO (Trimble et al., 1983) is most commonly performed as a single-stage procedure in which
Composition of the Study Group
Type of Cleft
Male
Female
Total
T1
T2
T3
T4
T5
CP RUCLP LUCLP BCLP Total
1 1 11 2 15
2 0 0 2 4
3 1 11 4 19
3 1 11 4 19
3 0 6 4 13
2 1 8 2 13
3 1 11 4 19
2 0 7 4 13
Carpentier et al., MAXILLARY TRANSVERSAL WIDTH AFTER SCHUCHARDT OSTEOTOMY
TABLE 2B
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Mean Age 6 SD in Years at Each Time Point
Mean age 6 SD
T1
Surgery
T2
T3
T4
T5
14.0 6 2.6
15.2 6 2.1
15.6 6 2.3
17.6 6 1.8
18.9 6 2.0
20.2 6 1.9
the horizontal buccal osteotomy is completed at least 7 mm above the apices of the teeth extending from the bone-graft region to the pterygomaxillary fissure. After all the necessary osteotomies have been completed, the lateral maxillary segment can be mobilized. To prevent interferences during transverse expansion, some minimal amount of bone is removed in the zygomatic buttress region. A toothborne hyrax, that is, an expansion device consisting of an expansion screw, is banded on the first premolars and first molars at the end of the surgical procedure. The expansion treatment consist of the surgical procedure and orthodontic treatment, performing a distraction within healthy bone through the maxillary expansion device and causing a substantial enlargement of the palatal vault and maxillary apical bases. Depending on the patient, the SPSMO will be performed unilaterally at the right or left side. The patient with RUCLP received an SPSMO at the right side, and all 11 patients with LUCLP received an SPSMO at the left side. If a bilateral expansion is desired, as in all 4 patients with BCLP, the surgery is staged in two separate procedures with an interval of 6 months. This enables the surgeon and orthodontist to have exact control of the expansion and allows the patient to chew at the nonoperated side. The mean age (6 SD) at the time of surgery in our study group was 15.2 6 2.1 years (Table 2B). After surgery, a latency period of 5 to 7 days was indicated. After this period of initial healing, patients were instructed to activate the expansion screw twice a day, which accounts for a 0.5-mm expansion. The patients were monitored once a week until the planned expansion was achieved, usually after 2 to 3 weeks. In most cases, presurgical orthodontics with fixed appliances produced the desired shape and width of the mandibular arch. Once the mandibular arch had reached its final shape, the appropriate maxillary expansion could be determined as the palatal cuspid of the maxillary molar was positioned on top of the buccal cuspid of the mandibular molar. Brackets were bonded on the maxillary teeth 3 months after the expansion was completed. As part of the retention protocol, the hyrax was kept in place 6 months to preserve the gained transversal width. After the expansion device was removed, maxillary width was retained by placing a transpalatal bar. Orthodontic treatment with fixed appliances was usually finished 1 to 2 years later. At the time of debonding, a removable Hawley retainer was placed in the maxilla and a fixed lingual retainer was bonded from canine to canine in the mandible. Patients were instructed to wear the removable Hawley retainer continuously during the first 3 months after debonding; afterward, it could be reduced to
only nighttime wear. A strict posttreatment follow-up was provided. In the literature, very little information is available on the evaluation of transverse expansion of the maxilla by means of an SPSMO in patients with CLP, which made it difficult to compare our results with a CLP control group matching for type of cleft. Orthodontic correction of a maxillary transverse discrepancy in patients without CLP by rapid palatal expansion (RPE) is successful until closure of the midpalatal suture at approximately 14 to 15 years of age depending on the patient’s gender (Koudstaal et al., 2009a). Although patients in our study group were approximately the same age, an RPE study could not serve as control group as the equivalent of a healthy midpalatal suture is absent in patients with CLP (Gorlin et al., 1990; Scollozi et al., 2007). Once skeletal maturity has been reached and the midpalatal suture has closed, SARPE must be performed to release the areas of bony resistance, such as the midpalatal suture, zygomatic buttresses, and piriform aperture (Koudstaal et al., 2009). As adult patients without CLP no longer have a functional midpalatal suture, we decided to compare our results with those of a group of adult patients without CLP from the literature. The aim of the study of Chamberland and Proffit (2008, 2011) was to assess the amount of dental and skeletal expansion and stability after SARPE. Thirty-eight adult patients presenting a unilateral or bilateral crossbite were enrolled in their prospective study (Chamberland and Proffit, 2011). Changes in maxillary width observed in our study group were compared with the changes Chamberland and Proffit (2008, 2011) observed in their SARPE study control group. Statistical analysis was performed and a linear mixed model was fit with time as the fixed factor and the patient as the random factor. A normal quantile plot indicated that the residuals were normally distributed. The comparison between the data from this study and the data from the SARPE study was performed using metaregression. A P value , .05 was considered statistically significant. RESULTS According to the Pearson correlation, intraobserver and interobserver reliability for the dental cast measurements was 0.99/0.95 and 0.98 respectively (P , .001). The mean value of the four measurements was used for further analysis. Measurements of the maxillary width are shown in Table 3. Dental changes are shown in Table 4, along with their statistical significance. Statistical analysis was performed on the entire study group (n ¼ 19), patients with CP (n ¼ 3),
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TABLE 3
Measurements in the Maxillary Arch During Combined SPSMO Expansion and Orthodontic Treatment of Patients with CLP Mean 6 SD (mm)
Time Point
Position
T1 T2 T3 T4 T5 T1 T2 T3 T4 T5 T1 T2 T3 T4 T5
Canine Canine Canine Canine Canine Premolar Premolar Premolar Premolar Premolar Molar Molar Molar Molar Molar
Study Group (n ¼ 19) 22.7 29.2 31.2 31.2 30.4 26.0 35.6 35.8 34.8 33.5 39.4 44.7 45.4 44.8 43.6
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
CP (n ¼ 3)
4.8 5.4 4.5 3.8 4.2 3.2 3.1 3.8 2.5 2.9 3.0 2.9 4.6 2.9 3.7
26.3 33.9 35.5 32.6 31.9 26.0 36.5 39.6 35.1 33.1 39.9 48.0 47.1 42.1 40.7
patients with UCLP (n ¼ 12), and patients with BCLP (n ¼ 4). The mean maxillary intercanine measurements at T1 in patients with UCLP (23.6 mm) and patients with BCLP (16.4 mm) were, respectively, 5 and 9 standard deviations below the standard mean value (33 mm) according to Moorees (1959), which validates the need for two SPSMO interventions in patients with BCLP. As mentioned before, patients with UCLP received an SPSMO at the cleft side combined with a maxillary expansion, whereas patients with BCLP received two SPSMO surgeries, one on each cleft side, combined with maxillary expansion. Statistical analysis was performed to compare the maxillary expansion in 19 patients with CLP receiving an SPSMO with 38 adult patients without CLP receiving an SARPE. When comparing both groups, the only statistical significant outcome was that canine expansion was greater in the study group (Table 5). No significant difference was observed for the other measurements. When looking at the
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
UCLP (n ¼ 12)
0.9 3.4 2.2 1.6 1.3 3.4 1.3 3.4 1.5 1.3 1.6 3.6 3.3 2.7 4.7
23.6 30.2 32.7 32.5 31.2 26.7 36.3 36.4 35.7 35.3 40.3 47.9 47.0 45.9 45.6
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
BCLP (n ¼ 4)
3.2 3.9 3.5 2.3 3.2 2.6 3.6 2.5 1.8 1.0 2.7 3.3 3.1 2.4 2.5
16.4 21.8 22.7 26.2 26.5 26.0 36.6 36.4 34.9 33.3 39.2 49.1 46.1 44.8 43.5
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
5.8 1.5 2.4 4.8 4.5 3.7 3.7 3.9 2.6 2.9 4.0 4.1 4.5 2.9 3.9
different subgroups, no evidence for a significant difference could be found for the CP and BCLP group. The UCLP group, however, also showed a significantly greater canine expansion than the SARPE control group. DISCUSSION Our study group comprised more male than female patients. This predominance of boys was also reflected in the distribution of the type of cleft according to the patient’s gender, except for CP. According to increasing incidence, we noticed the following ranking of type of cleft: RUCLP (n¼1), CP (n¼3), BCLP (n¼4), and LUCLP (n¼11). This distribution pattern is in agreement with the literature (Derijcke et al., 1996). The review of Derijcke et al. (1996) showed a higher incidence of CLP compared with CP; they also found that the left side was affected twice as often as the right side. The left side was 11 times more affected than the right side in our study group. Derijcke et al. (1996) also
TABLE 4 Dental Changes in Arch Width During Combined SPSMO Expansion and Orthodontic Treatment Within the Total Study Group and Subgroups and Their Statistical Significance** CLP (n ¼ 19)
CPO (n ¼ 3)
UCLP (n ¼ 12)
BCLP (n ¼ 4)
Variable
Estimated Value
P Value
Estimated Value
P Value
Estimated Value
P Value
Estimated Value
P Value
Canine T2–T1 (maximum expansion) Canine T4–T2 (relapse) Canine T4–T1 (net expansion) Canine T5–T4 (long term relapse) Canine T5–T1 (net changes) Premolar T2–T1 Premolar T4–T2 Premolar T4–T1 Premolar T5–T4 Premolar T5–T1 Molar T2–T1 Molar T4–T2 Molar T4–T1 Molar T5–T4 Molar T5–T1
7.3353 1.3275 8.6628 0.3242 8.9869 10.2333 1.2463 8.987 0.5238 8.4633 8.65 3.6774 4.9726 0.7758 4.1968
.0001** .4872 .0001** .9857 .0001** .0001** .3223 .0001** .8986 .0001** .0001** .0002** .0001** .8136 .0001**
7.54 1.3 6.25 0.02 6.23 10.54 1.45 9.08 1.11 7.98 8.20 5.91 2.29 1.15 1.13
.004** .79 .012** .99 .02** .0008** .73 .001** .89 .006** .0003** .0018** .13 .71 .71
7.25 1.72 8.98 0.19 9.17 10.05 1.04 9.01 0.14 9.15 8.44 2.73 5.71 0.07 5.63
.0001** .42 .0001** .99 .0001** .0001** .55 .0001** .99 .0001** .0001** .06 .0001** .99 .0001**
5.56 4.25 9.81 0.37 10.19 10.16 0.98 9.19 1.5 7.69 7.74 3.28 4.46 1.78 2.68
.14 .33 .004** .99 .003** .002** .96 .002** .85 .007** .017** .46 .15 .81 .56
** P , .01.
Carpentier et al., MAXILLARY TRANSVERSAL WIDTH AFTER SCHUCHARDT OSTEOTOMY
TABLE 5
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Comparison Between SARPE* and SPSMO expansion CLP (n ¼ 19)
CP (n ¼ 3)
UCLP (n ¼ 12)
BCLP (n ¼ 4)
Variable
Estimation SARPE
Estimation SPSMO
P Value
Estimation SPSMO
P Value
Estimation SPSMO
P Value
Estimation SPSMO
P Value
Canine net expansion Canine long-term relapse Canine net changes Premolar net expansion Premolar long-term relapse Premolar net changes Molar net expansion Molar long-term relapse Molar net changes
2.9546 0.06 2.547 5.4621 0.493 4.894 5.4467 0.987 6.152
8.3264 0.0938 8.4479 9.0069 0.7188 9.1042 4.9583 0.8542 4.8438
.0315** .9677 .1299 .0547 .8237 .1476 .6479 .8971 .5256
6.25 0.25 6.06 9.08 1.18 8.75 2.29 0.87 0.93
.104 .765 .234 .109 .672 .177 .08 .928 .122
8.97 0.16 9.33 90.1 0.16 10.01 5.71 0.62 6.64
0.0304** .92 .13 .06 .70 .12 .82 .77 .79
7.79 0.16 7.59 8.91 1.7 7.21 4.62 1.37 3.25
.081 .88 .17 .11 .45 .29 .52 .61 .23
* Chamberland and Proffit (2011). ** P , .01.
showed a predominance of girls in the CP group, whereas the CLP group comprised mainly boys. As already mentioned, conventional RPE to treat transverse maxillary deficiency cannot be performed in patients with CLP who have already undergone secondary alveolar bone grafting because of the absence of the equivalent of a healthy midpalatal suture (Scolozzi et al., 2007). The reason why the CLPT-UHL chooses to correct severe transverse collapsed maxilla at a relatively young age through combined SPSMO and orthodontic treatment is to minimize the need for a heavy three-piece osteotomy of the maxilla at an adult age. Only a small decrease in the transversal width was seen during orthodontic treatment, which was only statistically significant across the molars for the entire study group and the CP group. In most cases, this transverse relapse is of no clinical importance because overcorrection was performed during the hyrax treatment to anticipate relapse. Chamberland and Proffit (2011) found that skeletal changes with SARPE were modest but stable. They even ranked the skeletal changes with SARPE high in the hierarchy of stability of orthognathic surgery. Relapse in dental expansion was almost totally attributed to palatal movement of the posterior teeth. Comparing maxillary expansion after SPSMO in patients with CLP with those after SARPE in adult patients without CLP showed similar overall results. Both studies (SPSMO group and SARPE group) achieved correction of the dental crossbite and preserved the correction of the transverse maxillary deficiency as no long-term relapse could be found in either group. However, the canine expansion was statistically significant different between both groups. The achieved maxillary expansion at T2 measured across the canines was significantly greater for the patients with CLP in the entire SPSMO group and in the UCLP group. This difference might be explained by the severe initial transverse maxillary collapse at the alveolar cleft region. The lateral maxillary segment in patients with CLP has mostly a palatal pretreatment position, whereas the posterior part hinges in the pterygomaxillary junction
during expansion. Swennen et al. (2003), Heidbuchel et al. (1998), and Latief et al. (2009) also saw asymmetric transverse deficiency in patients with UCLP caused by collapse of the lateral maxillary segment at the cleft side. A statistically significant difference for canine expansion could also have been expected between the BCLP and control group as an initial severe transversal collapse is often clinically seen in the canine region. This clinical observation is also represented by the mean values of the measurements across the canines (Table 3): 16.4 6 5.8 for patients with BCLP versus 23.6 6 3.2 for patients with UCLP at T1. The fact that no significant difference could be shown is due to the small number of patients in the BCLP group (n ¼ 4). Figure 1A and 1B shows such a severe collapsed maxillary arch in a patient with BCLP in our study group. In our study, SPSMO was always performed in combination with a toothborne hyrax as part of the CLPT-UHL surgical protocol. As suggested by Mommaerts et al. (1999), a toothborne expansion device might cause unwanted side-effects, including possible loss of anchorage, tooth tipping, maxillary segmental tipping, cortical fenestration, damage to the dentition, periodontal membrane compression, and buccal root resorption. To avoid these complications, several boneborne expansion devices have been developed that are placed directly on the palatal bone during surgery. Several studies have compared the results of toothborne versus boneborne expansion devices in adult patients without CLP receiving a SARPE. Koudstaal et al. (2009b) concluded that there is no significant difference between the two groups considering stability, segmental maxillary tipping, and relapse. Swennen et al. (2003) described the use of a boneborne distraction device in patients with UCLP receiving a unilateral posterior maxillary subapical osteotomy. Performing a segmental unilateral transpalatal distraction (TPD) in patients with CLP, Swennen et al. (2003) encountered some differences compared with traditional TPD procedures described by Mommaerts et al. (1999). Therefore, Swennen et al. (2003) suggested that modifying
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FIGURE 1 A: Pretreatment situation of a patient with BCLP. B: The same patient with BCLP after treatment.
the device is necessary for segmental unilateral TPD in patients with UCLP. Ideally, the distraction device should allow vector modification and simultaneous transversal and vertical interceptive distraction osteogenesis (Swennen et al., 2003). In this retrospective study, we only measured the transverse maxillary width on a dental level. Looking at the skeletal level on anterior-posterior cephalograms or cone beam computed tomography (CBCT), would have given us a more accurate knowledge of the skeletal expansion, changes, and relapse during the whole treatment procedure. Chamberland and Proffit (2011) also suggested focusing on skeletal rather than dental stability. Because the patients treated at CLPT-UHL did not receive anteriorposterior cephalograms or CBCTs on a regular base during their treatment, analysis of the skeletal changes could not be performed in our study group. Furthermore, dental stability is most important in occlusion and thereby in the function of patients with CLP. Relapse is defined as the gradual recurrence of the abnormality for which distraction was performed (Koudstaal et al., 2009). It is not yet well understood in the literature why relapse occurs. Koudstaal et al. (2009b) suggested that scar tissue contraction after distraction is the most important factor. Posttreatment retention is an important factor for stability (Chamberland and Proffit, 2011). In our study, a relapse (T5 to T4) of 0.77 mm across the first molar was noticed. This was in line with the findings of Berger et al. (1998), Progel et al. (1992), de Freitas et al. (2008), Koudstaal et al. (2009), and Chamberland and Proffit (2011).
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Scolozzi P, Verdeja R, Herzog G, Jaques B. Maxillary expansion using transpalatal distraction in patients with unilateral cleft lip and palate. Plast Reconstr Surg. 2007;119:2200–2205. Swennen G, Treutlein C, Brachvogel P, Berten JL, Schwestka-Polly R, Hausamen JE. Segmental unilateral transpalatal distraction in cleft patients. J Craniofac Surg. 2003;14:786–790. Trimble LD, Tideman H, Stoelinga PJW. A modification of the pterygoid plate separation in low-level maxillary osteotomies. J Oral Maxillofac Surg. 1983;41:544–546. Yang C, Pan X, Qian Y, Wang G. Impact of rapid maxillary expansion in unilateral cleft lip and palate patients after secondary alveolar bone grafting: review and case report. Oral Maxillofac J. 2012;114:25–30. Ye B, Ruan C, Hu J, Yang Y, Ghosh A, Jana S, Zhang G. A comparative study on dental-arch morphology in adult unoperated and operated cleft palate patients. J. Craniofac Surg. 2010;21:811– 815.
ORIGINAL ARTICLE Evaluation of Transverse Maxillary Expansion After a Segmental Posterior Subapical Maxillary Osteotomy in Cleft Lip and Palate Patients With Severe Collapse of the Lateral Maxillary Segments S. Carpentier, D.D.S., J. van Gastel, D.D.S, Ph.D., J. Schoenaers, M.D., D.D.S., Ph.D., C. Carels, D.D.S., Ph.D., V. Vander Poorten, M.D., Ph.D., W. Coucke, M.Stat., Ph.D., A. Verdonck, D.D.S., Ph.D. Objective: The purpose of this longitudinal retrospective study was to evaluate transverse maxillary expansion after a Schuchardt or segmental posterior subapical maxillary osteotomy (SPSMO) in patients with cleft lip and palate (CLP). A second aim was to compare these data with data for adult patients without CLP who were receiving a surgical assisted rapid palatal expansion (SARPE). Method: The study group comprised 19 patients with CLP and a severe transversally collapsed maxilla who were treated with SPSMO followed by hyrax expansion at the University Hospitals Leuven. Dental casts of the 19 patients were analyzed before treatment, at maximum expansion, during orthodontic treatment, at the completion of orthodontic treatment. and 2 years after orthodontic treatment and were measured at the canine, premolar, and molar levels. Adult patients without CLP who were enrolled in a prospective study served as the control group. Results: Maxillary expansion within the study group was significantly greater (P , .05) at all measured levels compared with the maxillary arch before treatment. No significant relapse was measured in the study group 2 years after orthodontic treatment. When comparing the study and control groups, the only statistical difference was that canine expansion was significantly greater in the study group. Conclusion: SPSMO followed by maxillary expansion and orthodontic treatment is an appropriate treatment option to correct a severe transversally collapsed maxilla in patients with CLP. The overall treatment effect of SPSMO expansion is comparable with the effects of SARPE, although canine expansion was greater in the SPSMO group. KEY WORDS: cleft lip and palate, maxillary expansion, segmental posterior subapical maxillary osteotomy, transversal maxillary width
Most patients with cleft lip and palate (CLP) present transverse maxillary deficiency. Clinically, this can be seen as a unilateral or bilateral crossbite. A review of the literature suggests that the growth of the maxillary dental arch in patients with CLP is inhibited owing to congenital developmental deficiency, palatal muscle strain, scar retraction, and a history of surgical treatment (Yang et al., 2012). Ye et al. (2010) found that the major cause of maxillary dental arch constriction was scar tissue distribution on the palate. In the initial healing phase, transverse growth of the alveolar bone in patients with CLP is affected by wound contraction and the contractile force exerted by myofibroblasts in granulation tissue. The scar tissue that subsequently forms on denuded bone might impair the maxillary alveolar growth long term (Kim et al., 2002). The purpose of the present study was to evaluate transverse maxillary expansion after a Schuchardt osteotomy or segmental posterior subapical maxillary osteotomy (SPSMO) in patients with CLP and a severe transversally collapsed maxilla. The SPSMO was performed to create a paramedian osteotomy site within healthy maxillary bone.
Dr. Carpentier is a postgraduate student in orthodontics, Katholieke Universiteit Leuven, Leuven, Belgium. Dr. van Gastel is a member of the clinical staff, Orthodontic Department, Katholieke Universiteit Leuven, Leuven, Belgium. Dr. Verdonck is Professor of Orthodontics, Department of Oral Health Sciences, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium. Dr. Carels is Professor of Orthodontics, Department of Oral Health Sciences, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium. Dr. Schoenaers is Professor of Stomatology and Maxillofacial Surgery, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium; Dr. Vander Poorten is Professor of Otorhinolaryngology and Head and Neck Surgery, Katholieke Universiteit Leuven, and member of the Cleft Lip and Palate Team, University Hospitals, Leuven, Belgium. Dr. Coucke is Statistician, Department of Quality of Medical Laboratories, Scientific Institute of Public Health, Brussels, Belgium. Submitted September 2013; Revised January 2014; Accepted March 2014. Address correspondence to: Prof. Dr. A. Verdonck, Department of Oral Health Sciences - Orthodontics, Katholieke Universiteit Leuven, Kapucijnenvoer 7, B-3000 Leuven, Belgium. DOI: 10.1597/113-232 651
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TABLE 1
Standard Treatment Protocol at CLPT-UHL Procedure
Timing
Alveolar molding in selected patients Lip closure; two-stage procedure in patients with BCLP Soft palate closure Maxillary expansion with a removable appliance when the small segment has collapsed Hard palate closure Maxillary expansion with a removable appliance when the small segment has collapsed Secondary alveolar bone grafting SPSMO in selected patients who still have a severe collapsed maxilla with crossbite Orthodontic treatment Follow-up
A second aim was to compare these data with the data for adult patients without CLP (Chamberland et al., 2011) who were receiving a surgical assisted rapid palatal expansion (SARPE). MATERIAL
AND
METHODS
About 450 patients with CLP attend an annual multidisciplinary consultation with the cleft lip and palate team of the University Hospitals Leuven (CLPT-UHL) until they reach the age of 20. The standard treatment protocol at CLPT-UHL, which is always adapted to the individual needs of the patient, is demonstrated in Table 1. From the patient population with CLP consulting the CLPT-UHL between May 1996 and November 2009, 31 nonsyndromic patients with CLP showed a severe transversally collapsed maxilla. Only 19 of them were included in this longitudinal retrospective study, which was approved by the clinical trial center (ethics review committee) at University Hospitals Leuven (Table 2A). The other 12 patients with CLP were excluded because of lack of sufficient data. All 19 patients, 4 girls and 15 boys (mean age, 14.0 6 2.6 years), were nonsyndromic patients with CLP who were white, had no major medical history, and had a comparable social background. All patients presented a transversally constricted maxilla, which is defined as a maxillary intercanine width less than 33 6 2 mm at the age of 14 (Moorees, 1959). They were treated according to the CLPT-UHL protocol and received an SPSMO, which was performed by the same experienced surgeon and was followed by a maxillary expansion through a toothborne hyrax and orthodontic intervention. The following types of TABLE 2A
Before lip closure 3 months 1 year Before hard palate closure 5–6 years Before alveolar bone grafting When 2/3 of the root of the maxillary canine has formed After consolidation of alveolar bone graft and eruption of the canine Permanent dentition Lifetime
clefts were seen in the study group (Table 2A): three patients with cleft palate (CP), one patient with right unilateral cleft CLP (RUCLP), 11 patients with left unilateral CLP (LUCLP), and four patients with bilateral CLP (BCLP). Dental casts of the patients enrolled in this study were analyzed immediately before SPSMO (T1, n ¼ 19), at completion of maxillary expansion (T2, n ¼ 13), during orthodontic treatment (T3, n ¼ 13), at the completion of orthodontic treatment (T4, n ¼ 19), and 2 years after orthodontic treatment (T5, n ¼ 13) (Table 2A). Changes in tooth positions and maxillary width were evaluated by measurements on the available dental casts at each time point, T1 to T5, using a caliper (Mitutyo Asia Pacific Ltd., Singapore) with a precision of 0.5 mm). Intercanine width was measured at the cusp tip, inter-premolar width was measured in the mesial fossa of the first premolar, and intermolar width was measured in the central fossa of the first molar. All measurements were performed twice, at a 2week interval, by two independent observers. The SPSMO was originally described by Schuchardt in 1959 as a two-stage procedure for correcting open bite deformities. It is now also used as part of the treatment protocol at the CLPT-UHL in patients with CLP presenting a severe transversally collapsed maxilla. The SPSMO procedure is performed in the permanent dentition after consolidation of the secondary alveolar bone graft procedure and eruption of the cuspid. Dental age of the patient with CLP is very important because the maxillary canine and the second molar have to be erupted to perform the SPSMO. The SPSMO (Trimble et al., 1983) is most commonly performed as a single-stage procedure in which
Composition of the Study Group
Type of Cleft
Male
Female
Total
T1
T2
T3
T4
T5
CP RUCLP LUCLP BCLP Total
1 1 11 2 15
2 0 0 2 4
3 1 11 4 19
3 1 11 4 19
3 0 6 4 13
2 1 8 2 13
3 1 11 4 19
2 0 7 4 13
Carpentier et al., MAXILLARY TRANSVERSAL WIDTH AFTER SCHUCHARDT OSTEOTOMY
TABLE 2B
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Mean Age 6 SD in Years at Each Time Point
Mean age 6 SD
T1
Surgery
T2
T3
T4
T5
14.0 6 2.6
15.2 6 2.1
15.6 6 2.3
17.6 6 1.8
18.9 6 2.0
20.2 6 1.9
the horizontal buccal osteotomy is completed at least 7 mm above the apices of the teeth extending from the bone-graft region to the pterygomaxillary fissure. After all the necessary osteotomies have been completed, the lateral maxillary segment can be mobilized. To prevent interferences during transverse expansion, some minimal amount of bone is removed in the zygomatic buttress region. A toothborne hyrax, that is, an expansion device consisting of an expansion screw, is banded on the first premolars and first molars at the end of the surgical procedure. The expansion treatment consist of the surgical procedure and orthodontic treatment, performing a distraction within healthy bone through the maxillary expansion device and causing a substantial enlargement of the palatal vault and maxillary apical bases. Depending on the patient, the SPSMO will be performed unilaterally at the right or left side. The patient with RUCLP received an SPSMO at the right side, and all 11 patients with LUCLP received an SPSMO at the left side. If a bilateral expansion is desired, as in all 4 patients with BCLP, the surgery is staged in two separate procedures with an interval of 6 months. This enables the surgeon and orthodontist to have exact control of the expansion and allows the patient to chew at the nonoperated side. The mean age (6 SD) at the time of surgery in our study group was 15.2 6 2.1 years (Table 2B). After surgery, a latency period of 5 to 7 days was indicated. After this period of initial healing, patients were instructed to activate the expansion screw twice a day, which accounts for a 0.5-mm expansion. The patients were monitored once a week until the planned expansion was achieved, usually after 2 to 3 weeks. In most cases, presurgical orthodontics with fixed appliances produced the desired shape and width of the mandibular arch. Once the mandibular arch had reached its final shape, the appropriate maxillary expansion could be determined as the palatal cuspid of the maxillary molar was positioned on top of the buccal cuspid of the mandibular molar. Brackets were bonded on the maxillary teeth 3 months after the expansion was completed. As part of the retention protocol, the hyrax was kept in place 6 months to preserve the gained transversal width. After the expansion device was removed, maxillary width was retained by placing a transpalatal bar. Orthodontic treatment with fixed appliances was usually finished 1 to 2 years later. At the time of debonding, a removable Hawley retainer was placed in the maxilla and a fixed lingual retainer was bonded from canine to canine in the mandible. Patients were instructed to wear the removable Hawley retainer continuously during the first 3 months after debonding; afterward, it could be reduced to
only nighttime wear. A strict posttreatment follow-up was provided. In the literature, very little information is available on the evaluation of transverse expansion of the maxilla by means of an SPSMO in patients with CLP, which made it difficult to compare our results with a CLP control group matching for type of cleft. Orthodontic correction of a maxillary transverse discrepancy in patients without CLP by rapid palatal expansion (RPE) is successful until closure of the midpalatal suture at approximately 14 to 15 years of age depending on the patient’s gender (Koudstaal et al., 2009a). Although patients in our study group were approximately the same age, an RPE study could not serve as control group as the equivalent of a healthy midpalatal suture is absent in patients with CLP (Gorlin et al., 1990; Scollozi et al., 2007). Once skeletal maturity has been reached and the midpalatal suture has closed, SARPE must be performed to release the areas of bony resistance, such as the midpalatal suture, zygomatic buttresses, and piriform aperture (Koudstaal et al., 2009). As adult patients without CLP no longer have a functional midpalatal suture, we decided to compare our results with those of a group of adult patients without CLP from the literature. The aim of the study of Chamberland and Proffit (2008, 2011) was to assess the amount of dental and skeletal expansion and stability after SARPE. Thirty-eight adult patients presenting a unilateral or bilateral crossbite were enrolled in their prospective study (Chamberland and Proffit, 2011). Changes in maxillary width observed in our study group were compared with the changes Chamberland and Proffit (2008, 2011) observed in their SARPE study control group. Statistical analysis was performed and a linear mixed model was fit with time as the fixed factor and the patient as the random factor. A normal quantile plot indicated that the residuals were normally distributed. The comparison between the data from this study and the data from the SARPE study was performed using metaregression. A P value , .05 was considered statistically significant. RESULTS According to the Pearson correlation, intraobserver and interobserver reliability for the dental cast measurements was 0.99/0.95 and 0.98 respectively (P , .001). The mean value of the four measurements was used for further analysis. Measurements of the maxillary width are shown in Table 3. Dental changes are shown in Table 4, along with their statistical significance. Statistical analysis was performed on the entire study group (n ¼ 19), patients with CP (n ¼ 3),
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TABLE 3
Measurements in the Maxillary Arch During Combined SPSMO Expansion and Orthodontic Treatment of Patients with CLP Mean 6 SD (mm)
Time Point
Position
T1 T2 T3 T4 T5 T1 T2 T3 T4 T5 T1 T2 T3 T4 T5
Canine Canine Canine Canine Canine Premolar Premolar Premolar Premolar Premolar Molar Molar Molar Molar Molar
Study Group (n ¼ 19) 22.7 29.2 31.2 31.2 30.4 26.0 35.6 35.8 34.8 33.5 39.4 44.7 45.4 44.8 43.6
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
CP (n ¼ 3)
4.8 5.4 4.5 3.8 4.2 3.2 3.1 3.8 2.5 2.9 3.0 2.9 4.6 2.9 3.7
26.3 33.9 35.5 32.6 31.9 26.0 36.5 39.6 35.1 33.1 39.9 48.0 47.1 42.1 40.7
patients with UCLP (n ¼ 12), and patients with BCLP (n ¼ 4). The mean maxillary intercanine measurements at T1 in patients with UCLP (23.6 mm) and patients with BCLP (16.4 mm) were, respectively, 5 and 9 standard deviations below the standard mean value (33 mm) according to Moorees (1959), which validates the need for two SPSMO interventions in patients with BCLP. As mentioned before, patients with UCLP received an SPSMO at the cleft side combined with a maxillary expansion, whereas patients with BCLP received two SPSMO surgeries, one on each cleft side, combined with maxillary expansion. Statistical analysis was performed to compare the maxillary expansion in 19 patients with CLP receiving an SPSMO with 38 adult patients without CLP receiving an SARPE. When comparing both groups, the only statistical significant outcome was that canine expansion was greater in the study group (Table 5). No significant difference was observed for the other measurements. When looking at the
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
UCLP (n ¼ 12)
0.9 3.4 2.2 1.6 1.3 3.4 1.3 3.4 1.5 1.3 1.6 3.6 3.3 2.7 4.7
23.6 30.2 32.7 32.5 31.2 26.7 36.3 36.4 35.7 35.3 40.3 47.9 47.0 45.9 45.6
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
BCLP (n ¼ 4)
3.2 3.9 3.5 2.3 3.2 2.6 3.6 2.5 1.8 1.0 2.7 3.3 3.1 2.4 2.5
16.4 21.8 22.7 26.2 26.5 26.0 36.6 36.4 34.9 33.3 39.2 49.1 46.1 44.8 43.5
6 6 6 6 6 6 6 6 6 6 6 6 6 6 6
5.8 1.5 2.4 4.8 4.5 3.7 3.7 3.9 2.6 2.9 4.0 4.1 4.5 2.9 3.9
different subgroups, no evidence for a significant difference could be found for the CP and BCLP group. The UCLP group, however, also showed a significantly greater canine expansion than the SARPE control group. DISCUSSION Our study group comprised more male than female patients. This predominance of boys was also reflected in the distribution of the type of cleft according to the patient’s gender, except for CP. According to increasing incidence, we noticed the following ranking of type of cleft: RUCLP (n¼1), CP (n¼3), BCLP (n¼4), and LUCLP (n¼11). This distribution pattern is in agreement with the literature (Derijcke et al., 1996). The review of Derijcke et al. (1996) showed a higher incidence of CLP compared with CP; they also found that the left side was affected twice as often as the right side. The left side was 11 times more affected than the right side in our study group. Derijcke et al. (1996) also
TABLE 4 Dental Changes in Arch Width During Combined SPSMO Expansion and Orthodontic Treatment Within the Total Study Group and Subgroups and Their Statistical Significance** CLP (n ¼ 19)
CPO (n ¼ 3)
UCLP (n ¼ 12)
BCLP (n ¼ 4)
Variable
Estimated Value
P Value
Estimated Value
P Value
Estimated Value
P Value
Estimated Value
P Value
Canine T2–T1 (maximum expansion) Canine T4–T2 (relapse) Canine T4–T1 (net expansion) Canine T5–T4 (long term relapse) Canine T5–T1 (net changes) Premolar T2–T1 Premolar T4–T2 Premolar T4–T1 Premolar T5–T4 Premolar T5–T1 Molar T2–T1 Molar T4–T2 Molar T4–T1 Molar T5–T4 Molar T5–T1
7.3353 1.3275 8.6628 0.3242 8.9869 10.2333 1.2463 8.987 0.5238 8.4633 8.65 3.6774 4.9726 0.7758 4.1968
.0001** .4872 .0001** .9857 .0001** .0001** .3223 .0001** .8986 .0001** .0001** .0002** .0001** .8136 .0001**
7.54 1.3 6.25 0.02 6.23 10.54 1.45 9.08 1.11 7.98 8.20 5.91 2.29 1.15 1.13
.004** .79 .012** .99 .02** .0008** .73 .001** .89 .006** .0003** .0018** .13 .71 .71
7.25 1.72 8.98 0.19 9.17 10.05 1.04 9.01 0.14 9.15 8.44 2.73 5.71 0.07 5.63
.0001** .42 .0001** .99 .0001** .0001** .55 .0001** .99 .0001** .0001** .06 .0001** .99 .0001**
5.56 4.25 9.81 0.37 10.19 10.16 0.98 9.19 1.5 7.69 7.74 3.28 4.46 1.78 2.68
.14 .33 .004** .99 .003** .002** .96 .002** .85 .007** .017** .46 .15 .81 .56
** P , .01.
Carpentier et al., MAXILLARY TRANSVERSAL WIDTH AFTER SCHUCHARDT OSTEOTOMY
TABLE 5
655
Comparison Between SARPE* and SPSMO expansion CLP (n ¼ 19)
CP (n ¼ 3)
UCLP (n ¼ 12)
BCLP (n ¼ 4)
Variable
Estimation SARPE
Estimation SPSMO
P Value
Estimation SPSMO
P Value
Estimation SPSMO
P Value
Estimation SPSMO
P Value
Canine net expansion Canine long-term relapse Canine net changes Premolar net expansion Premolar long-term relapse Premolar net changes Molar net expansion Molar long-term relapse Molar net changes
2.9546 0.06 2.547 5.4621 0.493 4.894 5.4467 0.987 6.152
8.3264 0.0938 8.4479 9.0069 0.7188 9.1042 4.9583 0.8542 4.8438
.0315** .9677 .1299 .0547 .8237 .1476 .6479 .8971 .5256
6.25 0.25 6.06 9.08 1.18 8.75 2.29 0.87 0.93
.104 .765 .234 .109 .672 .177 .08 .928 .122
8.97 0.16 9.33 90.1 0.16 10.01 5.71 0.62 6.64
0.0304** .92 .13 .06 .70 .12 .82 .77 .79
7.79 0.16 7.59 8.91 1.7 7.21 4.62 1.37 3.25
.081 .88 .17 .11 .45 .29 .52 .61 .23
* Chamberland and Proffit (2011). ** P , .01.
showed a predominance of girls in the CP group, whereas the CLP group comprised mainly boys. As already mentioned, conventional RPE to treat transverse maxillary deficiency cannot be performed in patients with CLP who have already undergone secondary alveolar bone grafting because of the absence of the equivalent of a healthy midpalatal suture (Scolozzi et al., 2007). The reason why the CLPT-UHL chooses to correct severe transverse collapsed maxilla at a relatively young age through combined SPSMO and orthodontic treatment is to minimize the need for a heavy three-piece osteotomy of the maxilla at an adult age. Only a small decrease in the transversal width was seen during orthodontic treatment, which was only statistically significant across the molars for the entire study group and the CP group. In most cases, this transverse relapse is of no clinical importance because overcorrection was performed during the hyrax treatment to anticipate relapse. Chamberland and Proffit (2011) found that skeletal changes with SARPE were modest but stable. They even ranked the skeletal changes with SARPE high in the hierarchy of stability of orthognathic surgery. Relapse in dental expansion was almost totally attributed to palatal movement of the posterior teeth. Comparing maxillary expansion after SPSMO in patients with CLP with those after SARPE in adult patients without CLP showed similar overall results. Both studies (SPSMO group and SARPE group) achieved correction of the dental crossbite and preserved the correction of the transverse maxillary deficiency as no long-term relapse could be found in either group. However, the canine expansion was statistically significant different between both groups. The achieved maxillary expansion at T2 measured across the canines was significantly greater for the patients with CLP in the entire SPSMO group and in the UCLP group. This difference might be explained by the severe initial transverse maxillary collapse at the alveolar cleft region. The lateral maxillary segment in patients with CLP has mostly a palatal pretreatment position, whereas the posterior part hinges in the pterygomaxillary junction
during expansion. Swennen et al. (2003), Heidbuchel et al. (1998), and Latief et al. (2009) also saw asymmetric transverse deficiency in patients with UCLP caused by collapse of the lateral maxillary segment at the cleft side. A statistically significant difference for canine expansion could also have been expected between the BCLP and control group as an initial severe transversal collapse is often clinically seen in the canine region. This clinical observation is also represented by the mean values of the measurements across the canines (Table 3): 16.4 6 5.8 for patients with BCLP versus 23.6 6 3.2 for patients with UCLP at T1. The fact that no significant difference could be shown is due to the small number of patients in the BCLP group (n ¼ 4). Figure 1A and 1B shows such a severe collapsed maxillary arch in a patient with BCLP in our study group. In our study, SPSMO was always performed in combination with a toothborne hyrax as part of the CLPT-UHL surgical protocol. As suggested by Mommaerts et al. (1999), a toothborne expansion device might cause unwanted side-effects, including possible loss of anchorage, tooth tipping, maxillary segmental tipping, cortical fenestration, damage to the dentition, periodontal membrane compression, and buccal root resorption. To avoid these complications, several boneborne expansion devices have been developed that are placed directly on the palatal bone during surgery. Several studies have compared the results of toothborne versus boneborne expansion devices in adult patients without CLP receiving a SARPE. Koudstaal et al. (2009b) concluded that there is no significant difference between the two groups considering stability, segmental maxillary tipping, and relapse. Swennen et al. (2003) described the use of a boneborne distraction device in patients with UCLP receiving a unilateral posterior maxillary subapical osteotomy. Performing a segmental unilateral transpalatal distraction (TPD) in patients with CLP, Swennen et al. (2003) encountered some differences compared with traditional TPD procedures described by Mommaerts et al. (1999). Therefore, Swennen et al. (2003) suggested that modifying
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FIGURE 1 A: Pretreatment situation of a patient with BCLP. B: The same patient with BCLP after treatment.
the device is necessary for segmental unilateral TPD in patients with UCLP. Ideally, the distraction device should allow vector modification and simultaneous transversal and vertical interceptive distraction osteogenesis (Swennen et al., 2003). In this retrospective study, we only measured the transverse maxillary width on a dental level. Looking at the skeletal level on anterior-posterior cephalograms or cone beam computed tomography (CBCT), would have given us a more accurate knowledge of the skeletal expansion, changes, and relapse during the whole treatment procedure. Chamberland and Proffit (2011) also suggested focusing on skeletal rather than dental stability. Because the patients treated at CLPT-UHL did not receive anteriorposterior cephalograms or CBCTs on a regular base during their treatment, analysis of the skeletal changes could not be performed in our study group. Furthermore, dental stability is most important in occlusion and thereby in the function of patients with CLP. Relapse is defined as the gradual recurrence of the abnormality for which distraction was performed (Koudstaal et al., 2009). It is not yet well understood in the literature why relapse occurs. Koudstaal et al. (2009b) suggested that scar tissue contraction after distraction is the most important factor. Posttreatment retention is an important factor for stability (Chamberland and Proffit, 2011). In our study, a relapse (T5 to T4) of 0.77 mm across the first molar was noticed. This was in line with the findings of Berger et al. (1998), Progel et al. (1992), de Freitas et al. (2008), Koudstaal et al. (2009), and Chamberland and Proffit (2011).
CONCLUSION The combined SPSMO and orthodontic treatment is an appropriate treatment option to correct the transversally collapsed maxilla in patients with CLP who have already received a secondary alveolar bone graft. The overall treatment effect of the SPSMO expansion in patients with CLP is comparable with the effects of SARPE in adult patients without CLP; the canine net expansion is greater in the SPSMO group. REFERENCES Berger J, Pangrazio-Kulbersh V, Borgula T, Kaczynski R. Stability of orthopedic and surgically assisted rapid palatal expansion over time. Am J Orthod Dentofacial Orthop. 1998;114:638–645. Chamberland S, Proffit W. Closer look at the stability of surgically assisted rapid palatal expansion. J Oral Maxillofac Surg. 2008;66:1895–1900. Chamberland S, Proffit W. Short-term and long-term stability of surgically assisted rapid palatal expansion revisited. Am J Orthod Dentofacial Orthop. 2011;139:815–822. Derijcke A, Eerens A, Carels C. The incidence of oral clefts: a review. Br J Oral Maxillofac Surg. 1996;34:488–494. de Freitas R, Goncalves A, Moniz N, Maciel F. Surgically assisted maxillary expansion in adults: prospective study. Int J Oral Maxillofac Surg. 2008;37:779–804. Gorlin R, Cohen M, Levin L. Syndromes of the Head and Neck. New York: Oxford University Press; 1990:693–696. Heidbuchel K, Kuijpers-Jagtman A, Kramer G, Prahl-Andersen B. Maxillary arch dimensions in bilateral cleft lip and palate from birth until four years of age in boys. Cleft Palate Craniofac J. 1998;35:233–239. Kim T, Ishikawa H, Chu S, Handa A, Iida J, Yoshida S. Constriction of the maxillary dental arch by mucoperiosteal denudation of the palate. Cleft Palate Craniofac J. 2002;39:425–431.
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