ORIGINAL ARTICLE
Maxillary Distraction Osteogenesis Using a Rigid External Distractor: Which Clinical Factors Are Related With Relapse? Jeenam Kim, MD, Ki-il Uhm, MD, PhD, Donghyeok Shin, MD, Jina Lee, DDS,y and Hyungon Choi, MD, PhD Introduction: Maxillary distraction osteogenesis is a reliable treatment for cleft lip and palate with midfacial retrusion. The purpose of this study was to evaluate the results of long-term follow-up in patients with cleft lip and palate after maxillary distraction osteogenesis and to find clinical factors related to relapse. From February 2002 to June 2008, 21 patients with severe class III malocclusion were treated at our hospital. We performed distraction osteotomy with a rigid external distractor device. The distraction length was more than 15 mm in all patients. Methods: Preoperative and postoperative lateral cephalometric radiographs were used for analysis. The sella-nasion-subnasale, sella-nasion-supramentale, and point-A-point-B-nasion (sellanasion-subnasale–sella-nasion-supramentale) angles were recorded. The timelines for follow-up were preoperatively, after distraction, after consolidation, at 3 years, and once fully grown (5to 8-year follow-ups). A comparative analysis of clinical factors was performed for the relapsing and nonrelapsing groups. Results: Of the 21 patients, 14 had relapsed. The mean age in the relapsing group was 9.1 years (7 boys and 7 girls) with 9 patients with unilateral cleft palate and 5 c bilateral cleft palate. The mean age in the nonrelapsing group was 11.7 years (4 boys and 3 girls) with 5 patients with unilateral cleft palate and 2 patients with bilateral cleft palate. Discussion: Despite greater anterior overcorrection, relapse occurred owing to scar tissue retraction and mandibular compensatory hypertrophy. The results suggest that the younger the patient, the more likely relapse will occur. Key Words: Rigid external distraction, distraction osteogenesis, orthognathic surgery (J Craniofac Surg 2015;26: 1178–1181)
T
he first clinical application of distraction osteogenesis in the craniofacial skeleton according to the principles developed by
From the Department of Plastic Surgery, Konkuk University School of Medicine, Seoul; and yPrivate Practice, Korea. Received July 20, 2014. Accepted for publication January 14, 2015. Address correspondence and reprint requests to Hyungon Choi, MD, PhD, Department of Plastic Surgery, Konkuk University School of Medicine, 120-1 Neungdong-ro, Gwangjin-gu, Seoul 143-729, Korea; E-mail: [email protected] The authors report no conflict of interest. Copyright # 2015 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001568
1178
Ilizarov was performed by McCarthy et al.1 Maxillary distraction osteogenesis is a reliable treatment for severe maxillary deficiency in patients with cleft lip and palate.2 Approximately 25% of patients with cleft palate with class III malocclusion and/or a skeletal class III jaw relationship require surgical intervention.3 LeFort I osteotomy is commonly used for correction of maxillary deficiency in patients with cleft palate as well as in patients without cleft palate, but the tendency to relapse and the extent of the relapse tend to be higher in patients with cleft palate.4 The percentages of relapse varied from 4% to 40%, with much higher rates with longer-term follow-up. The primary causes of relapse are thought to be the existence of mobilization and stabilization difficulties when there are large discrepancies between the bony segments, scarring of the palate, and tightness of the upper lip.3 There is a lack of information about long-term stability after distraction. The purpose of this study was to evaluate the long-term follow-up of maxillary distraction osteogenesis using a rigid external distraction device and to find clinical factors related to relapse.
PATIENTS AND METHODS Distraction osteogenesis was performed at UM plastic surgery clinic and Konkuk University Medical Center by a senior author. A retrospective review of medical records was performed, including radiologic images taken before and after surgery. Between February 2002 and June 2008, we performed distraction osteotomy with a rigid external distractor device (RED I System; KLS-Martin LP, Tuttlingen, Germany) on 21 patients with severe class III malocclusion enrolled in this study. All of these patients allowed for longterm follow-up until growth completion. Thirteen patients had unilateral cleft lip and palate, 1 patient had a unilateral cleft lip and alveolus, 6 patients had bilateral cleft lip and palate, and 1 patient had a bilateral cleft lip and unilateral cleft alveolus. There were 10 female and 11 male patients. The timing of surgery was between 8 and 14 years, depending on visiting period of patients. All patients underwent preoperative orthodontic alignment of their dental arches with fixed appliances. The osteotomy performed was the LeFort I procedure with pterygomaxillary and septal disjunctions. After completion of the osteotomy, the RED I system was attached to the cranium with 4 scalp screws. After a latency period of 5 days, the maxillary distraction was begun at a rate of 1 to 1.5 mm per day. Maxillary distraction was continued until distraction length reached 15–20 mm. The external distraction device was left in place for 5–6 weeks after completion of the distraction. The distraction device was removed and replaced with a facial mask for 6 months for consolidation. After the consolidation period, all patients were followed annually until reaching growth completion. Preoperative and postoperative lateral cephalometric radiographs were analyzed by 2 authors. The sella-nasion-subnasale (SNA), the sella-nasion-supramentale (SNB), and the point-A-topoint-B-nasion [SNA-SNB (ANB)] angles were recorded. The timeline for follow-up was before distraction, after distraction,
The Journal of Craniofacial Surgery
Volume 26, Number 4, June 2015
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 4, June 2015
TABLE 2-2. Baseline Characteristics
TABLE 1. Changes During Maxillary Distraction Osteogenesis After After Preoperatively Distraction Consolidation
3 Years After Operation
After Grown up
85.7 83.3 2.4
84.3 84.8 0.5
Cleft type SNA SNB ANB
77.7 82.2 4.5
90.8 82.0 8.8
90.0 82.0 8.0
Sex Cleft palate
Data are expressed as mean values.
Outcome
after consolidation, at 3 years, and after full growth (>5-year follow-up). Completion of growth was determined by closure of the growth plate on wrist radiography. Comparative analysis of clinical factors (age, sex, unilateral or bilateral cleft, and existence of cleft palate) was performed between the relapsing and nonrelapsing groups. The relapsing group consisted of patients who needed additional orthognathic surgery after puberty. Logistic regression analyses were performed to estimate odds ratios.
RESULTS The maxilla was advanced successfully to the desired position without complications. No significant postoperative morbidity or infection was observed. The mean SNA angle was 77.7 degrees preoperatively, 90.8 degrees after distraction, 90.0 degrees after consolidation, 86.8 degrees at the 3-year follow-up, and 84.2 degrees once fully grown. The mean SNB angle was 82.2 degrees preoperatively, 82.0 degrees after distraction, 82.0 degrees after consolidation, 83.3 degrees at the 3-year follow-up, and 84.7 degrees once fully grown. The mean ANB angle was 4.5 degrees preoperatively, 8.8 degrees after distraction, 8.0 degrees after consolidation, 3.5 degrees at the 3-year follow-up, and 0.5 degrees once fully grown (Table 1). Because the length of time to full growth differed in all patients, it is difficult to interpret statistical significance. Fourteen of 21 patients relapsed and needed additional orthognathic surgery. Twelve of 14 patients underwent double-jaw surgery, one patient had LeFort I osteotomy with titanium plate and screw fixation, and one patient needed sagittal split ramus osteotomy but she refused the surgery. The mean age of the relapsing group was 9.1 years (7 boys and 7 girls); 9 patients had unilateral cleft, and 5 patients had bilateral cleft. The mean age of the nonrelapsing group was 11.7 years (4 boys and 3 girls), 5 patients of whom had unilateral cleft and 2 patients had bilateral cleft. In this study, 2 patients were without cleft palate, and they did not relapse. Age was the only factor of significant difference between the groups (P ¼ 0.0357). The other factors had no statistical significance (Tables 2–1 to 4–2).
Patient 1 No Relapse After Distraction Osteogenesis A 12-year-old female patient presented with unilateral cleft lip and alveolus. She had undergone cheiloplasty at the age 3 months. At the age of 8 years, she had gingivoperiosteoplasty and iliac bone graft. After patient’s growth, the maxillary hypoplasia progressed. She had skeletal class III malocclusion. LeFort I osteotomy was TABLE 2-1. Baseline Characteristics
Age
#
N
Mean
SD
Min
Max
21
9.95
1.75
8.00
14.00
2015 Mutaz B. Habal, MD
Maxillary Osteogenesis and Factors
Unilateral Bilateral Male Female Palate Alveolus Nonrelapse Relapse Total
n
(%)
14 7 12 9 19 2 7 14 21
(66.67) (33.33) (57.14) (42.86) (90.48) (9.52) (33.33) (66.67) (100.00)
performed, and distraction was performed at a rate of 1 mm per day for 15 days. The SNA angle was 81.0 degrees preoperatively, 97.0 degrees after distraction, 96.0 degrees after consolidation, 94.4 degrees at 3-year follow-up, and 92.7 degrees once fully grown. The ANB angle was 5.7 degrees preoperatively, 8.7 degrees after distraction, 7.2 degrees after consolidation, 4.9 degrees at 3-year follow-up, and 2.3 degrees once fully grown. She had class I occlusion until fully grown and therefore did not need additional orthognathic surgery (Fig. 1).
Patient 2 Relapse After Distraction Osteogenesis A 9-year-old female patient presented with unilateral cleft lip and palate. She had undergone cheiloplasty and palatoplasty at ages 3 and 12 months, respectively. At age 8 years, she had gingivoperiosteoplasty and iliac bone graft. After the patient’s growth, maxillary hypoplasia progressed. Her diagnosis was skeletal class III malocclusion. LeFort I osteotomy was performed, and distraction was performed at a rate of 1 mm per day for 15 days. The SNA angle was 80.6 degrees preoperatively, 90.3 degrees after distraction, 88.2 degrees after consolidation, 84.3 degrees at 3-year follow-up, and 81.0 degrees once fully grown. The ANB angle was 2.7 degrees preoperatively, 7.2 degrees after distraction, 5.5 degrees after consolidation, 1.1 degrees at 3-year follow-up, and 5.9 degrees once fully grown. She had LeFort I osteotomy and bilateral sagittal split ramus osteotomy when she was 20 years old (Fig. 2).
DISCUSSION This study evaluated long-term changes and clinical factors regarding relapse in patients with cleft palate who received maxillary distraction osteogenesis with RED devices to correct severe maxillary retrusion. Recently, distraction osteogenesis has become a popular surgical modality because of its many advantages: It is a relatively safe, effective, and minimally invasive procedure that can be performed at any age, with a low rate of complications.5 However, there is a very high relapse rate in patients with cleft palate, and causes of relapse are often described in the literature. Baek et al6 noted the relapsing rate of cleft lip and palate patients is 25% to 50%; whereas in TABLE 3. Univariate Logistic Regression Analysis
Age Cleft type Sex Cleft palate
Unilateral/Bilateral Male/Female Palate/Alveolus
Odds Ratio
95% Confidence Interval
P
0.110 0.720 1.000 >999.999
0.014–0.863 0.100–5.167 0.160–6.255 < 0.001 > 999.999
0.0357 0.7439 1.0000 0.9700
1179
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Kim et al
Volume 26, Number 4, June 2015
TABLE 4-1. Wilcoxon Rank Sum Test Nonrelapse
Age
Relapse
N
Mean
SD
Min
Max
N
Mean
SD
Min
Max
P
7
11.71
1.80
9.00
14.00
14
9.07
0.83
8.00
10.00
0.0017
Wilcoxon rank sum test. patients without cleft palate, it is known to be 10%. This discrepancy can be explained by retraction of the scar tissue, tightness of the upper lip, interference with the nasal septum, and inadequate mobilization of the bony segment.6 Huang et al stated the maxilla gradually moves backward and downward for up to 1 year. In most growing children with cleft lip and palate, there was no further forward growth of the maxilla after distraction. Because the pterygomaxillary junction is an important growth site and is in line with the osteotomy cut and the region of new bone formation during distraction, forward growth of the maxilla may be affected adversely owing to disturbance of this growth site or obliteration of this junction. A secondary factor is pressure from the soft tissue and musculature, which may have a longer-lasting effect, adversely affecting maxillary forward growth.1 When the maxilla is distracted, soft tissues along with the bony structures are also distracted. In a patient without cleft palate, soft tissue changes well by the surgery; but in cleft patient, soft tissue is scarring in palate and maxillary region. Thus, the soft tissue of patients with cleft palate is not fully distracted, causing retraction of the maxilla, and the newly generated bone is not compact enough to resist the tight soft tissue envelope.7 Most patients with cleft lip and palate have severe maxillary anterior crowding and premolar lesions as well as congenitally missing teeth. Therefore, it is essential to create a new alveolar bone to simultaneously obtain proper alignment of teeth and correct maxillary hypoplasia.8 Krimmel et al9 described one patient who had a bilateral cleft lip and palate, and mobile premaxilla with no bone graft to the alveolar cleft before distraction. The 3 segments did not consolidate to the midface after distraction. Krimmel et al stated that slight anterior overcorrection can compensate for partial relapse and growth deficit; Cho et al stated that 20% to 30% anterior overcorrection is needed.9 In this study, further anterior overcorrection was done, and all patients with alveolar cleft underwent iliac bone grafting 1 year before distraction to create a stable maxillary arch. Therefore, the vector and level of distraction were easily controlled as one unit. Surgical skill can be another factor in relapse. We confirmed more than 15 mm of anterior movement of the maxilla in the operating room; therefore, in this study, our results were not influenced by surgical skill.
FIGURE 1. Cephalogram of patient. Patient 1: Before the operation (A), after distraction (B), after consolidation (C), at 3-year follow-up (D), and once fully grown (8-year follow-up) (E).
Likewise, despite efforts to reduce relapse, the relapse rate was increased from other studies. Thus, we studied comparative analysis of clinical factors to find causes for relapse. The mean age of the relapsing group was 9.1 years (7 boys and 7 girls), with 9 patients having unilateral cleft and 5 patients having bilateral cleft. The mean age of the nonrelapsing group was
TABLE 4-2. Chi-Square Analysis Nonrelapse
Cleft type
Unilateral Bilateral Total Sex Male Female Total Cleft palate Palate Alveolus Total
1180
n
(%)
5 2 7 4 3 7 5 2 7
(71.43) (28.57) (33.33) (57.14) (42.86) (33.33) (71.43) (28.57) (33.33)
Relapse n
(%)
Total n
(%)
P
9 (64.29) 14 (66.67) 1.0000 5 (35.71) 7 (33.33) Fisher exact test 14 (66.67) 21 (100.00) 8 (57.14) 12 (57.14) 1.0000 6 (42.86) 9 (42.86) Fisher exact test 14 (66.67) 21 (100.00) 14 (100.00) 19 (90.48) 0.1000 0 (0.00) 2 (9.52) Fisher exact test 14 (66.67) 21 (100.00)
FIGURE 2. Cephalogram of patient. Patient 2: Before the operation (A), after distraction (B), after consolidation (C), at 3-year follow-up (D), once fully grown (8-year follow-up) (E), before the 2-jaw surgery (F), and after the 2-jaw surgery (G).
#
2015 Mutaz B. Habal, MD
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 4, June 2015
11.7 years (4 boys and 3 girls), with 5 patients having unilateral cleft and 2 patients having bilateral cleft. In this study, 2 patients without cleft palate did not relapse; therefore, comparison was not possible. Age was the only factor of significant difference between the groups (P ¼ 0.0357). The other factors had no statistical significance. Cho et al9 reported that after the age of 9 years, age cannot inhibit anteroposterior growth of the maxilla. However, studies with a longer follow-up period are needed to evaluate a much larger patient population. As the mean age of the relapsing group was 9.1 years in our study, we suggest that distraction osteogenesis should be done at an older age. To reduce bias, all cephalometric tracings and calculations were performed by 2 independent plastic surgeons. Despite these efforts, our study had some limitations. First, comparisons were not made with untreated patients. Second, the number of patients evaluated was small, with a higher risk of sampling error. The design of this study was also retrospective, and not randomized. Therefore, a prospective randomized clinical trial could have prevented the introduction of selection bias.
REFERENCES 1. Huang CS, Harikrishnan P, Liao YF, et al. Long-term follow-up after maxillary distraction osteogenesis in growing children with cleft lip and palate. Cleft Palate Craniofac J 2007;44:274–277
#
2015 Mutaz B. Habal, MD
Maxillary Osteogenesis and Factors
2. Doucet JC, Herlin C, Bigorre M, et al. Mandibular effects of maxillary distraction osteogenesis in cleft lip and palate. Int J Oral Maxillofac Surg 2014;43:702–707 3. Seda G, Jyri H, Kirsti H. Five-year follow-up of maxillary distraction osteogenesis on the dentofacial structures of children with cleft lip and palate. J Oral Maxillofac Surg 2010;68:744–750 4. Heliovaara A, Ranta R, Hukki J, et al. Skeletal stability of Le Fort I osteotomy in patients with isolated cleft palate and bilateral cleft lip and palate. Int J Oral Maxillofac Surg 2002;31:358–363 5. Meazzini MC, Mazzoleni F, Gabriele C, et al. Mandibular distraction osteogenesis in hemifacial microsomia: long-term follow-up. J Craniomaxillofac Surg 2005;33:370–376 6. Baek SH, Lee JK, Lee JH, et al. Comparison of treatment outcome and stability between distraction osteogenesis and LeFort I osteotomy in cleft patients with maxillary hypoplasia. J Craniofac Surg 2007;18: 1209–1215 7. Is¸eri H, Kis¸nis¸ci R, Altug˘-Atac¸ AT. Ten-year follow-up of a patient with hemifacial microsomia treated with distraction osteogenesis and orthodontics: an implant analysis. Am J Orthod Dentofac Orthop 2008;134:296–304 8. Choi HY, Hwang CJ, Kim HJ, et al. Maxillary anterior segmental distraction osteogenesis with 2 different types of distractors. J Craniofac Surg 2012;23:706–711 9. Cho BC, kyung HM. Distraction osteogenesis of the hypoplastic midface using a rigid external distraction system: the results of a one- to six-year follow-up. Plast Reconstr Surg 2006;118:1201–1212
1181
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Maxillary Distraction Osteogenesis Using a Rigid External Distractor: Which Clinical Factors Are Related With Relapse? Jeenam Kim, MD, Ki-il Uhm, MD, PhD, Donghyeok Shin, MD, Jina Lee, DDS,y and Hyungon Choi, MD, PhD Introduction: Maxillary distraction osteogenesis is a reliable treatment for cleft lip and palate with midfacial retrusion. The purpose of this study was to evaluate the results of long-term follow-up in patients with cleft lip and palate after maxillary distraction osteogenesis and to find clinical factors related to relapse. From February 2002 to June 2008, 21 patients with severe class III malocclusion were treated at our hospital. We performed distraction osteotomy with a rigid external distractor device. The distraction length was more than 15 mm in all patients. Methods: Preoperative and postoperative lateral cephalometric radiographs were used for analysis. The sella-nasion-subnasale, sella-nasion-supramentale, and point-A-point-B-nasion (sellanasion-subnasale–sella-nasion-supramentale) angles were recorded. The timelines for follow-up were preoperatively, after distraction, after consolidation, at 3 years, and once fully grown (5to 8-year follow-ups). A comparative analysis of clinical factors was performed for the relapsing and nonrelapsing groups. Results: Of the 21 patients, 14 had relapsed. The mean age in the relapsing group was 9.1 years (7 boys and 7 girls) with 9 patients with unilateral cleft palate and 5 c bilateral cleft palate. The mean age in the nonrelapsing group was 11.7 years (4 boys and 3 girls) with 5 patients with unilateral cleft palate and 2 patients with bilateral cleft palate. Discussion: Despite greater anterior overcorrection, relapse occurred owing to scar tissue retraction and mandibular compensatory hypertrophy. The results suggest that the younger the patient, the more likely relapse will occur. Key Words: Rigid external distraction, distraction osteogenesis, orthognathic surgery (J Craniofac Surg 2015;26: 1178–1181)
T
he first clinical application of distraction osteogenesis in the craniofacial skeleton according to the principles developed by
From the Department of Plastic Surgery, Konkuk University School of Medicine, Seoul; and yPrivate Practice, Korea. Received July 20, 2014. Accepted for publication January 14, 2015. Address correspondence and reprint requests to Hyungon Choi, MD, PhD, Department of Plastic Surgery, Konkuk University School of Medicine, 120-1 Neungdong-ro, Gwangjin-gu, Seoul 143-729, Korea; E-mail: [email protected] The authors report no conflict of interest. Copyright # 2015 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0000000000001568
1178
Ilizarov was performed by McCarthy et al.1 Maxillary distraction osteogenesis is a reliable treatment for severe maxillary deficiency in patients with cleft lip and palate.2 Approximately 25% of patients with cleft palate with class III malocclusion and/or a skeletal class III jaw relationship require surgical intervention.3 LeFort I osteotomy is commonly used for correction of maxillary deficiency in patients with cleft palate as well as in patients without cleft palate, but the tendency to relapse and the extent of the relapse tend to be higher in patients with cleft palate.4 The percentages of relapse varied from 4% to 40%, with much higher rates with longer-term follow-up. The primary causes of relapse are thought to be the existence of mobilization and stabilization difficulties when there are large discrepancies between the bony segments, scarring of the palate, and tightness of the upper lip.3 There is a lack of information about long-term stability after distraction. The purpose of this study was to evaluate the long-term follow-up of maxillary distraction osteogenesis using a rigid external distraction device and to find clinical factors related to relapse.
PATIENTS AND METHODS Distraction osteogenesis was performed at UM plastic surgery clinic and Konkuk University Medical Center by a senior author. A retrospective review of medical records was performed, including radiologic images taken before and after surgery. Between February 2002 and June 2008, we performed distraction osteotomy with a rigid external distractor device (RED I System; KLS-Martin LP, Tuttlingen, Germany) on 21 patients with severe class III malocclusion enrolled in this study. All of these patients allowed for longterm follow-up until growth completion. Thirteen patients had unilateral cleft lip and palate, 1 patient had a unilateral cleft lip and alveolus, 6 patients had bilateral cleft lip and palate, and 1 patient had a bilateral cleft lip and unilateral cleft alveolus. There were 10 female and 11 male patients. The timing of surgery was between 8 and 14 years, depending on visiting period of patients. All patients underwent preoperative orthodontic alignment of their dental arches with fixed appliances. The osteotomy performed was the LeFort I procedure with pterygomaxillary and septal disjunctions. After completion of the osteotomy, the RED I system was attached to the cranium with 4 scalp screws. After a latency period of 5 days, the maxillary distraction was begun at a rate of 1 to 1.5 mm per day. Maxillary distraction was continued until distraction length reached 15–20 mm. The external distraction device was left in place for 5–6 weeks after completion of the distraction. The distraction device was removed and replaced with a facial mask for 6 months for consolidation. After the consolidation period, all patients were followed annually until reaching growth completion. Preoperative and postoperative lateral cephalometric radiographs were analyzed by 2 authors. The sella-nasion-subnasale (SNA), the sella-nasion-supramentale (SNB), and the point-A-topoint-B-nasion [SNA-SNB (ANB)] angles were recorded. The timeline for follow-up was before distraction, after distraction,
The Journal of Craniofacial Surgery
Volume 26, Number 4, June 2015
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 4, June 2015
TABLE 2-2. Baseline Characteristics
TABLE 1. Changes During Maxillary Distraction Osteogenesis After After Preoperatively Distraction Consolidation
3 Years After Operation
After Grown up
85.7 83.3 2.4
84.3 84.8 0.5
Cleft type SNA SNB ANB
77.7 82.2 4.5
90.8 82.0 8.8
90.0 82.0 8.0
Sex Cleft palate
Data are expressed as mean values.
Outcome
after consolidation, at 3 years, and after full growth (>5-year follow-up). Completion of growth was determined by closure of the growth plate on wrist radiography. Comparative analysis of clinical factors (age, sex, unilateral or bilateral cleft, and existence of cleft palate) was performed between the relapsing and nonrelapsing groups. The relapsing group consisted of patients who needed additional orthognathic surgery after puberty. Logistic regression analyses were performed to estimate odds ratios.
RESULTS The maxilla was advanced successfully to the desired position without complications. No significant postoperative morbidity or infection was observed. The mean SNA angle was 77.7 degrees preoperatively, 90.8 degrees after distraction, 90.0 degrees after consolidation, 86.8 degrees at the 3-year follow-up, and 84.2 degrees once fully grown. The mean SNB angle was 82.2 degrees preoperatively, 82.0 degrees after distraction, 82.0 degrees after consolidation, 83.3 degrees at the 3-year follow-up, and 84.7 degrees once fully grown. The mean ANB angle was 4.5 degrees preoperatively, 8.8 degrees after distraction, 8.0 degrees after consolidation, 3.5 degrees at the 3-year follow-up, and 0.5 degrees once fully grown (Table 1). Because the length of time to full growth differed in all patients, it is difficult to interpret statistical significance. Fourteen of 21 patients relapsed and needed additional orthognathic surgery. Twelve of 14 patients underwent double-jaw surgery, one patient had LeFort I osteotomy with titanium plate and screw fixation, and one patient needed sagittal split ramus osteotomy but she refused the surgery. The mean age of the relapsing group was 9.1 years (7 boys and 7 girls); 9 patients had unilateral cleft, and 5 patients had bilateral cleft. The mean age of the nonrelapsing group was 11.7 years (4 boys and 3 girls), 5 patients of whom had unilateral cleft and 2 patients had bilateral cleft. In this study, 2 patients were without cleft palate, and they did not relapse. Age was the only factor of significant difference between the groups (P ¼ 0.0357). The other factors had no statistical significance (Tables 2–1 to 4–2).
Patient 1 No Relapse After Distraction Osteogenesis A 12-year-old female patient presented with unilateral cleft lip and alveolus. She had undergone cheiloplasty at the age 3 months. At the age of 8 years, she had gingivoperiosteoplasty and iliac bone graft. After patient’s growth, the maxillary hypoplasia progressed. She had skeletal class III malocclusion. LeFort I osteotomy was TABLE 2-1. Baseline Characteristics
Age
#
N
Mean
SD
Min
Max
21
9.95
1.75
8.00
14.00
2015 Mutaz B. Habal, MD
Maxillary Osteogenesis and Factors
Unilateral Bilateral Male Female Palate Alveolus Nonrelapse Relapse Total
n
(%)
14 7 12 9 19 2 7 14 21
(66.67) (33.33) (57.14) (42.86) (90.48) (9.52) (33.33) (66.67) (100.00)
performed, and distraction was performed at a rate of 1 mm per day for 15 days. The SNA angle was 81.0 degrees preoperatively, 97.0 degrees after distraction, 96.0 degrees after consolidation, 94.4 degrees at 3-year follow-up, and 92.7 degrees once fully grown. The ANB angle was 5.7 degrees preoperatively, 8.7 degrees after distraction, 7.2 degrees after consolidation, 4.9 degrees at 3-year follow-up, and 2.3 degrees once fully grown. She had class I occlusion until fully grown and therefore did not need additional orthognathic surgery (Fig. 1).
Patient 2 Relapse After Distraction Osteogenesis A 9-year-old female patient presented with unilateral cleft lip and palate. She had undergone cheiloplasty and palatoplasty at ages 3 and 12 months, respectively. At age 8 years, she had gingivoperiosteoplasty and iliac bone graft. After the patient’s growth, maxillary hypoplasia progressed. Her diagnosis was skeletal class III malocclusion. LeFort I osteotomy was performed, and distraction was performed at a rate of 1 mm per day for 15 days. The SNA angle was 80.6 degrees preoperatively, 90.3 degrees after distraction, 88.2 degrees after consolidation, 84.3 degrees at 3-year follow-up, and 81.0 degrees once fully grown. The ANB angle was 2.7 degrees preoperatively, 7.2 degrees after distraction, 5.5 degrees after consolidation, 1.1 degrees at 3-year follow-up, and 5.9 degrees once fully grown. She had LeFort I osteotomy and bilateral sagittal split ramus osteotomy when she was 20 years old (Fig. 2).
DISCUSSION This study evaluated long-term changes and clinical factors regarding relapse in patients with cleft palate who received maxillary distraction osteogenesis with RED devices to correct severe maxillary retrusion. Recently, distraction osteogenesis has become a popular surgical modality because of its many advantages: It is a relatively safe, effective, and minimally invasive procedure that can be performed at any age, with a low rate of complications.5 However, there is a very high relapse rate in patients with cleft palate, and causes of relapse are often described in the literature. Baek et al6 noted the relapsing rate of cleft lip and palate patients is 25% to 50%; whereas in TABLE 3. Univariate Logistic Regression Analysis
Age Cleft type Sex Cleft palate
Unilateral/Bilateral Male/Female Palate/Alveolus
Odds Ratio
95% Confidence Interval
P
0.110 0.720 1.000 >999.999
0.014–0.863 0.100–5.167 0.160–6.255 < 0.001 > 999.999
0.0357 0.7439 1.0000 0.9700
1179
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Kim et al
Volume 26, Number 4, June 2015
TABLE 4-1. Wilcoxon Rank Sum Test Nonrelapse
Age
Relapse
N
Mean
SD
Min
Max
N
Mean
SD
Min
Max
P
7
11.71
1.80
9.00
14.00
14
9.07
0.83
8.00
10.00
0.0017
Wilcoxon rank sum test. patients without cleft palate, it is known to be 10%. This discrepancy can be explained by retraction of the scar tissue, tightness of the upper lip, interference with the nasal septum, and inadequate mobilization of the bony segment.6 Huang et al stated the maxilla gradually moves backward and downward for up to 1 year. In most growing children with cleft lip and palate, there was no further forward growth of the maxilla after distraction. Because the pterygomaxillary junction is an important growth site and is in line with the osteotomy cut and the region of new bone formation during distraction, forward growth of the maxilla may be affected adversely owing to disturbance of this growth site or obliteration of this junction. A secondary factor is pressure from the soft tissue and musculature, which may have a longer-lasting effect, adversely affecting maxillary forward growth.1 When the maxilla is distracted, soft tissues along with the bony structures are also distracted. In a patient without cleft palate, soft tissue changes well by the surgery; but in cleft patient, soft tissue is scarring in palate and maxillary region. Thus, the soft tissue of patients with cleft palate is not fully distracted, causing retraction of the maxilla, and the newly generated bone is not compact enough to resist the tight soft tissue envelope.7 Most patients with cleft lip and palate have severe maxillary anterior crowding and premolar lesions as well as congenitally missing teeth. Therefore, it is essential to create a new alveolar bone to simultaneously obtain proper alignment of teeth and correct maxillary hypoplasia.8 Krimmel et al9 described one patient who had a bilateral cleft lip and palate, and mobile premaxilla with no bone graft to the alveolar cleft before distraction. The 3 segments did not consolidate to the midface after distraction. Krimmel et al stated that slight anterior overcorrection can compensate for partial relapse and growth deficit; Cho et al stated that 20% to 30% anterior overcorrection is needed.9 In this study, further anterior overcorrection was done, and all patients with alveolar cleft underwent iliac bone grafting 1 year before distraction to create a stable maxillary arch. Therefore, the vector and level of distraction were easily controlled as one unit. Surgical skill can be another factor in relapse. We confirmed more than 15 mm of anterior movement of the maxilla in the operating room; therefore, in this study, our results were not influenced by surgical skill.
FIGURE 1. Cephalogram of patient. Patient 1: Before the operation (A), after distraction (B), after consolidation (C), at 3-year follow-up (D), and once fully grown (8-year follow-up) (E).
Likewise, despite efforts to reduce relapse, the relapse rate was increased from other studies. Thus, we studied comparative analysis of clinical factors to find causes for relapse. The mean age of the relapsing group was 9.1 years (7 boys and 7 girls), with 9 patients having unilateral cleft and 5 patients having bilateral cleft. The mean age of the nonrelapsing group was
TABLE 4-2. Chi-Square Analysis Nonrelapse
Cleft type
Unilateral Bilateral Total Sex Male Female Total Cleft palate Palate Alveolus Total
1180
n
(%)
5 2 7 4 3 7 5 2 7
(71.43) (28.57) (33.33) (57.14) (42.86) (33.33) (71.43) (28.57) (33.33)
Relapse n
(%)
Total n
(%)
P
9 (64.29) 14 (66.67) 1.0000 5 (35.71) 7 (33.33) Fisher exact test 14 (66.67) 21 (100.00) 8 (57.14) 12 (57.14) 1.0000 6 (42.86) 9 (42.86) Fisher exact test 14 (66.67) 21 (100.00) 14 (100.00) 19 (90.48) 0.1000 0 (0.00) 2 (9.52) Fisher exact test 14 (66.67) 21 (100.00)
FIGURE 2. Cephalogram of patient. Patient 2: Before the operation (A), after distraction (B), after consolidation (C), at 3-year follow-up (D), once fully grown (8-year follow-up) (E), before the 2-jaw surgery (F), and after the 2-jaw surgery (G).
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2015 Mutaz B. Habal, MD
Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
Volume 26, Number 4, June 2015
11.7 years (4 boys and 3 girls), with 5 patients having unilateral cleft and 2 patients having bilateral cleft. In this study, 2 patients without cleft palate did not relapse; therefore, comparison was not possible. Age was the only factor of significant difference between the groups (P ¼ 0.0357). The other factors had no statistical significance. Cho et al9 reported that after the age of 9 years, age cannot inhibit anteroposterior growth of the maxilla. However, studies with a longer follow-up period are needed to evaluate a much larger patient population. As the mean age of the relapsing group was 9.1 years in our study, we suggest that distraction osteogenesis should be done at an older age. To reduce bias, all cephalometric tracings and calculations were performed by 2 independent plastic surgeons. Despite these efforts, our study had some limitations. First, comparisons were not made with untreated patients. Second, the number of patients evaluated was small, with a higher risk of sampling error. The design of this study was also retrospective, and not randomized. Therefore, a prospective randomized clinical trial could have prevented the introduction of selection bias.
REFERENCES 1. Huang CS, Harikrishnan P, Liao YF, et al. Long-term follow-up after maxillary distraction osteogenesis in growing children with cleft lip and palate. Cleft Palate Craniofac J 2007;44:274–277
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2015 Mutaz B. Habal, MD
Maxillary Osteogenesis and Factors
2. Doucet JC, Herlin C, Bigorre M, et al. Mandibular effects of maxillary distraction osteogenesis in cleft lip and palate. Int J Oral Maxillofac Surg 2014;43:702–707 3. Seda G, Jyri H, Kirsti H. Five-year follow-up of maxillary distraction osteogenesis on the dentofacial structures of children with cleft lip and palate. J Oral Maxillofac Surg 2010;68:744–750 4. Heliovaara A, Ranta R, Hukki J, et al. Skeletal stability of Le Fort I osteotomy in patients with isolated cleft palate and bilateral cleft lip and palate. Int J Oral Maxillofac Surg 2002;31:358–363 5. Meazzini MC, Mazzoleni F, Gabriele C, et al. Mandibular distraction osteogenesis in hemifacial microsomia: long-term follow-up. J Craniomaxillofac Surg 2005;33:370–376 6. Baek SH, Lee JK, Lee JH, et al. Comparison of treatment outcome and stability between distraction osteogenesis and LeFort I osteotomy in cleft patients with maxillary hypoplasia. J Craniofac Surg 2007;18: 1209–1215 7. Is¸eri H, Kis¸nis¸ci R, Altug˘-Atac¸ AT. Ten-year follow-up of a patient with hemifacial microsomia treated with distraction osteogenesis and orthodontics: an implant analysis. Am J Orthod Dentofac Orthop 2008;134:296–304 8. Choi HY, Hwang CJ, Kim HJ, et al. Maxillary anterior segmental distraction osteogenesis with 2 different types of distractors. J Craniofac Surg 2012;23:706–711 9. Cho BC, kyung HM. Distraction osteogenesis of the hypoplastic midface using a rigid external distraction system: the results of a one- to six-year follow-up. Plast Reconstr Surg 2006;118:1201–1212
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Copyright © 2015 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
