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A novel modification in combined Le Fort I and horseshoe osteotomy for posterior repositioning of the maxilla
Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176
Contents lists available at ScienceDirect
Asian Journal of Oral and Maxillofacial Surgery journal homepage: www.elsevier.com/locate/ajoms
Original research
A novel modification in combined Le Fort I and horseshoe osteotomy for posterior repositioning of the maxilla Izumi Yoshioka a,b,∗ , Amit Khanal a , Masaaki Kodama a , Manabu Habu a , Takeshi Nishikawa a , Kenjiro Iwanaga a, Shinya Kokuryo a, Akihiko Basugi a, Sumio Sakoda b, Jinichi Fukuda a, Kazuhiro Tominaga a a b
Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu, Fukuoka, Japan Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Miyazaki 5200 Kihara Kiyotake, Miyazaki, 889-1692, Japan
a r t i c l e
i n f o
Article history: Received 5 December 2010 Received in revised form 19 May 2011 Accepted 30 May 2011 Available online 23 June 2011 Keywords: Le Fort I osteotomy Horseshoe osteotomy Posterior repositioning of maxilla Accuracy
a b s t r a c t Objective: Posterior repositioning of the maxilla using a novel modification in combined Le Fort I and horseshoe osteotomy in bimaxillary surgeries is described and assessed for accuracy. Materials and methods: In this prospective study, posterior repositioning of maxilla was performed in a total of 10 patients where the planned posterior setback was at least 3 mm or greater. In all patients, the maxilla was first osteotomized with Le Fort I and horseshoe osteotomy in addition to a new technique to trim maxillary tuberosity and posterior palatal walls, and followed by bilateral sagittal split ramus osteotomy in the mandible with or without additional genioplasty. Lateral cephalograms were obtained preoperatively and 1 week postoperatively. The changes in upper incisor (U1) and upper molar mesial cusp tip (UMT) were examined. Results: The discrepancy between the planned and actual posterior movement was 0.35 and 0.28 mm at U1 and UMT, respectively. There were no severe complications such as intraoperative haemorrhage, avascular necrosis of the maxilla (partial/total), devitalization of teeth, and oroantral or oronasal fistulas in any of the cases. Conclusions: These results suggest that when greater posterior repositioning of the maxilla is indicated, this newly introduced novel modification in horseshoe osteotomy combined with Le Fort I osteotomy is an effective technique for safety and accuracy. © 2011 Asian Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
1. Introduction Maxillary protrusion is one of the most common dentofacial deformities, especially in Far-East Asian community [1]. Conventionally, maxillary skeletal protrusion used to be treated by orthodontic movements alone or combined surgical and orthodontic treatment consisting in extraction of two maxillary premolars associated with anterior maxillary segmental osteotomy. Although the anterior occlusal result comes out quite good, the esthetic impact is often unsatisfactory in severe maxillary protrusions [2]. Further, these methods do not correct for the generally associated vertical maxillary excess or the first molar class II relationship.
∗ Corresponding author at: University of Miyazaki, Department of Oral and Maxillofacial Surgery, Faculty of Medicine, 5200 Kihara Kiyotake, Miyazaki, 889-1692, Japan. Tel.: +81 985 85 3786; fax: +81 985 85 7190. E-mail address: [email protected] (I. Yoshioka).
Therefore, posterior repositioning of total maxilla using Le Fort I osteotomy is the treatment of choice in severe maxillary protrusion. The posterior movement of maxilla as a single segment after Le Fort I osteotomy is often difficult owing to the interferences of posterior maxillary bone around the great palatine canal and anterior part of pterygoid plates. Thus, removal of maxillary tuberosity and posterior palatal wall, and/or the anterior part of pterygoid plates are often necessary for posterior setbacks greater than 3 mm. Adversely, there are high chances of injuring descending palatine artery (DPA) or pterygoid plexus of veins, which can result in massive intraoperative haemorrhage and potential aseptic necrosis of the maxilla [3,4]. From the literature, there are very few studies regarding posterior movement of the maxilla in total [5,6]. Bell and McBride [7] for the first time introduced horseshoe palatal osteotomy in combination with Le Fort I osteotomy in 1977. Recently, the authors have described a modified technique of horseshoe osteotomy for superior impactions of the maxilla [8]. The biggest advantage of
0915-6992/$ – see front matter © 2011 Asian Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ajoms.2011.05.004
I. Yoshioka et al. / Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176
173
Fig. 1. (a) Diagram shows reduction of maxillary tuberosity in the dentoalveolar component using a round bur to allow posterior movement of the maxilla by carefully protecting the DPA along with palatine vessels in the palatal component. (b) 3-D model image of (a). (c) Anterior margin of the palatal component can be reduced in case of bony interferences between the anterior palatal component and dentoalveolar component during greater posterior setbacks. The periosteum and palatal mucosa is preserved. (d) 3-D model image of (c).
this technique is that it allows high superior impaction of maxilla especially in the posterior segment while preserving the DPA and maintains the nasal chamber volume. The current literature provides very little relevant information regarding posterior movement of the maxilla in total [5,6]. In this prospective study, we have made some novel modifications in our earlier described technique of horseshoe osteotomy for posterior setbacks of the maxilla [8]. Although its indications seem to be limited, this modification can play a role in the treatment of adult dentofacial class II deformity. The purpose of this article is to propose and report on a series of 10 patients who underwent posterior setbacks of their maxillas using the modified technique of combined Le Fort I and horseshoe osteotomy described below. Further, the accuracy of this technique is evaluated and presented.
2. Patients and methods 2.1. Patient selection The subjects were 10 adult Japanese patients referred for surgical correction of dentofacial deformity at Kyushu Dental College Hospital from 2006 to 2008. The patients were selected on basis where the planned posterior setback of maxilla was at least 3 mm or greater. Exclusion criteria were one jaw surgery; periodontal disease judged severe by the surgeon; previous maxillo-mandibular surgery and any history of trauma or craniofacial syndrome. Informed consent was obtained from patients and the study was approved by Kyushu Dental College Hospital. All the 10 patients (1 male, 9 female; age range: 19–25 years; median age 21 years)
underwent Le Fort I and horseshoe osteotomy accompanied by mandibular surgery. They had received pre-surgical orthodontics treatment consisting of decompensation and alignment of dental arch with bilateral maxillary first premolar extractions.
2.2. Surgical technique Nasoendotracheal intubation was followed by local anesthetics infiltration. Soft tissue dissection was performed in the standard fashion, as previously described [9]. Then conventional Le Fort I osteotomy was performed according to that of Bell’s technique [9]. Similarly, horseshoe osteotomy was performed according to our earlier described technique [8]. After horseshoe osteotomy, the dentoalveolar component was mobilized from the palatal component consisting bilateral DPA. To allow posterior setback of the maxilla, bone around maxillary tuberosities was carefully reduced using round bur. The maxillary tuberosities were trimmed carefully to avoid any injury to the DPA, dental roots and palatal mucosa. The palatal component consisting bilateral DPA was not trimmed (Fig. 1a and b). However, when greater setback of the maxilla is desired, bony interferences between the dentoalveolar component and anterior margin of the palatal component makes it difficult for posterior pushback. As earlier described [8], we have been utilizing a technique of further dividing the palatal component into 3 parts through 2 parallel osteotomies from the superior aspect. Osteotomizing the palatal component into 3 parts provide flexibility which helps in higher superior impaction of the dentoalveolar component. This time, we have introduced a simple technique of selectively reduc-
174
I. Yoshioka et al. / Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176
Fig. 2. An illustration showing the shaded areas that can be trimmed for posterior setbacks. The dotted lines represent horseshoe osteotomy with palatal component divided into three parts.
ing the anterior margin of palatal component with a round bur so that the dentoalveolar component can be easily repositioned backwards (Figs. 1c and d and 2). Periosteum and palatal mucosa were preserved. Double splint technique was applied in order to achieve the planned position of osteomized maxilla intraoperatively and fixed with four L-shaped titanium miniplates. In all cases, bilateral sagittal split ramus osteotomy (SSRO) with/without genioplasty was performed following Trauner/Obwegeser’s technique [10] and fixed with 2 semi rigid four-hole titanium miniplates at the anterior mandibular ramus. Both planning and operations were done by two senior surgeons of this department. 2.3. Method of analysis Subjects were evaluated 1-week before surgery (T0), and at postoperative 1 week (T1). Lateral cephalograms were taken with the patient oriented to the Frankfort Horizontal Plane. Reliability of repositioning was performed on lateral cephalograms (Fig. 3). Postoperative changes of the upper 1 (U1) and the upper first molar cusp tip (UMT) from Frankfort horizontal plane were measured immediately after releasing intermaxillary fixation. Discrepancy between prediction and actual horizontal and vertical movement of U1 and UMT were examined. All of these analyses were performed by one of the authors who were blinded to the study. The linear measures on lateral cephalograms used in this study are illustrated in Fig. 3. X- and Y-coordinate measurements were obtained by using a line parallel to the Frankfort horizontal plane for the X coordinate. A perpendicular line was then drawn inter-
Fig. 3. Method of analyzing lateral cephalograms for posterior movement of maxilla using the upper 1 (U1) and the upper molar mesial cusp tip (UMT) in relation with Frankfort plane.
secting the X-coordinate. These X- and Y-coordinated axes were transcribed onto each successive radiograph by superimposition on the “best fit” of sella, nasion, anterior and posterior cranial base landmarks. The relevant points were indicated on the X and Y axes. Movements of these points were represented as linear measurements in millimeters on both the axes. On the X-axis, posterior movement was indicated as a positive value, and anterior movement as a negative value. On the Y-axis, superior movement was indicated as a positive value, while inferior movement as a negative value. The paired t-test was used to identify the skeletal significance of difference between the planned surgical movements and post-surgical changes.Statistical significance was set at P < 0.05.
3. Results There were no severe complications such as intraoperative haemorrhage, avascular necrosis of the maxilla (partial/total), devitalization of teeth and oroantral or oronasal fistulas in any of the cases. The average blood loss was 742.00 mm (SD 330.13) and average operation time was 401.73 min (SD 82.61). Postoperatively, the multi segmented maxilla had a good bony healing as verified from
Table 1 Reliability of posterior repositioning. Case no.
1 2 3 4 5 6 7 8 9 10 Mean ± SD
U1
UMT
Predicted (mm)
Actual (mm)
Discrepancy (mm)
Predicted (mm)
Actual (mm)
Discrepancy (mm)
3.00 3.00 3.00 5.00 3.50 3.00 3.00 3.00 4.50 3.00 3.40 ± 0.70
2.47 3.26 2.84 4.70 3.99 3.56 2.79 2.62 4.73 3.42 3.44 ± 0.77
0.53 0.26 0.16 0.30 0.49 0.56 0.21 0.38 0.23 0.42 0.35 ± 0.14
3.00 3.00 3.00 5.00 3.50 3.00 3.00 3.00 4.50 3.00 3.36 ± 0.70
2.36 3.21 2.88 4.77 3.60 3.46 2.75 2.53 4.62 3.16 3.33 ± 0.77
0.64 0.21 0.12 0.23 0.10 0.46 0.25 0.47 0.12 0.16 0.28 ± 0.17
I. Yoshioka et al. / Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176
175
Table 2 Reliability of superior repositioning. Case no.
1 2 3 4 5 6 7 8 9 10 Mean ± SD
U1
UMT
Predicted (mm)
Actual (mm)
Discrepancy (mm)
Predicted (mm)
Actual (mm)
Discrepancy (mm)
4.00 3.00 3.00 5.00 3.00 0 2.00 1.50 1.00 2.00 2.45 ± 1.39
3.65 2.91 1.98 4.00 3.45 −0.28 2.15 1.35 1.10 1.53 2.18 ± 1.26
0.35 0.09 1.02 1.00 0.45 0.28 0.15 0.15 0.10 0.47 0.41 ± 0.33
5.00 2.00 3.50 5.00 3.00 0 3.50 1.50 2.00 5.00 3.05 ± 1.61
4.20 2.23 3.38 5.74 3.05 −0.88 3.50 1.15 1.35 4.52 2.82 ± 1.82
0.80 0.23 0.12 0.74 0.05 0.88 0 0.35 0.65 0.48 0.43 ± 0.31
radiographs and clinical examinations during follow up period of atleast 1 year. 3.1. Accuracy for repositioning of the maxilla Table 1 shows the reliability of posterior repositioning of the maxilla obtained by measuring U1 and the UMT. The mean posterior prediction was 3.36 mm (range 3.0–5.0 mm) with mean actual position being 3.33 mm accounting 0.28 mm as a discrepancy value between the planned and actual maxillary position at UMT. Similarly, the mean superior prediction was 3.05 mm (range 0–5.0 mm) and mean actual position being 2.82 mm with discrepancy value of 0.43 mm at UMT (Table 2). The vertical and horizontal difference between the planned and actual position of the maxilla was not statistically significant. This shows that the maxillas were repositioned nearly to their planned positions during surgery posteriorly as well as superiorly. 4. Discussion Conventionally, orthodontics treatment with bilateral premolar extraction is the most common way of treating maxillary protrusion. Recent advances in orthodontics technique, such as miniscrews allow maximum anchorage and further simplify this procedure [11]. However, orthodontics alone to retract the anterior teeth with bilateral premolar extractions has limitations owing to various factors such as the amount of tooth movement, periodontal status and patient’s age [12]. To overcome these limitations, anterior segmental osteotomy of the maxilla is sometimes recommended. Anterior segmental osteotomy can markedly reduce the treatment period over conventional orthodontics treatment and achieve immediate improvement of the facial profile [13]. However, the anterior segmental osteotomy often has many postoperative sequelae such as necrosis of repositioned anterior segment, devitalization of teeth, and ankylosis of canine, wound dehiscence at the osteotomy site and poor occlusal interdigitation in the canine-premolar region [9,14,15]. Posterior repositioning or setback of maxilla in total using Le Fort I osteotomy is often difficult due to bony interferences at the posterior edge. Hence, bone around the maxillary tuberosity and palatine canal should be reduced for an effective posterior movement. However, there are high chances of injuring descending palatine artery (DPA) during bone trimming leading to massive intraoperative haemorrhage. Further, in cases requiring greater amount of posterior setback even after maxillary trimming, pterygoid plates need to be sectioned and fractured to accommodate the desired setback amount. Although this procedure is rarely indicated, there is good clinical evidence supported by radiographic
documentation that high level pterygoid plate fractures can result in severe complications like haemorrhage and false aneurysm formation [4,16]. Our novel modification in combination of Le Fort I and horseshoe osteotomy for posterior repositioning of the maxilla is versatile in its design. This modification allows posterior setback as well as superior impactions without compromising on the DPA, nasal chamber volume and posterior airway space. It provides a greater posterior movement of maxilla unlike that offered by anterior segmental osteotomy, which is limited to the width of the extracted teeth or by a single segment Le Fort I osteotomy. The very fact that this technique provides space by the reduction of maxillary tuberosity and third molar (extracted socket) allows greater posterior pushbacks. We have achieved a maximum posterior repositioning of 4.77 mm at UMT by this technique with high accuracy of the planned posterior maxillary movement. While treating deformities having maxillary excess, not only posterior setbacks but superior impactions are often needed as seen in our reported cases. This modified technique is able to serve the both purposes of posterior and superior repositioning of the maxilla. In conclusion, extensive removal of maxillary tuberosity and posterior palatal wall could be safely obtained with this newly described novel modification in horseshoe osteotomy. Thus, when posterior repositioning of the maxilla is indicated, combining Le Fort I with horseshoe osteotomy is an available useful technique for safety and accuracy. We hope that this technique will be of great benefit while treating maxillary excesses, especially in the Far-East Asian population.
References [1] Miyajima K, Mcnamara JA, Kimura T, Murata S, Iizuka T. Craniofacial structure of Japanese and European-American adults with normal occlusions and wellbalanced faces. Am J Orthod Dentfacial Orthop 1996;110:431–8. [2] Baek SH, Kim BH. Determinants of successful treatment of bimaxillary protrusion orthodontic treatment versus anterior segmental osteotomy. J Craniofac Surg 2005;16:234–46. [3] Lanigan DT, Hey JH, West RA. Aseptic necrosis following maxillary osteotomies: report of 36 cases. J Oral Maxillofac Surg 1990;48:142–56. [4] Ueki K, Hashiba Y, Marukawa K, Nakagawa K, Okabe K, Yamamoto E. Determining the anatomy of the descending palatine artery and pterygoid plates with computed tomography in class III patients. J Craniomaxillofac Surg 2009;37:469–73. [5] Ward JL, Garri JI, Wolfe SA. Posterior movements of the maxilla. J Craniofac Surg 2007;18:882–6. [6] Hirose K, Shimoda T, Izumi K, Maeda A, Ozeki S. Three-dimensional assessment of the accuracy of maxillary repositioning by Le Fort I osteotomy with emphasis on maxillary backward transference. Asian J Oral Maxillofac Surg 2006;18:127–33. [7] Bell WH, McBride KL. Correction of the long face syndrome by Le Fort I results: a report on some new technical modifications and treatment results. Oral Surg Oral Med Oral Pathol 1977;44:493–520. [8] Yoshioka I, Khanal A, Kodama M, Furuta N, Tominaga K. Postoperative skeletal stability and accuracy of a new combined Le Fort I and horseshoe
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[11] [12]
I. Yoshioka et al. / Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176 osteotomy for superior repositioning of the maxilla. Int J Oral Maxillofac Surg 2009;38:1250–5. Bell WH, Proffit WR, White Jr RP. Surgical correction of dentofacial deformities. Philadelphia: WB Saunders; 1980. Trauner R, Obwegeser HL. The surgical correction of mandibular prognathism and retrognathia with consideration of genioplasty. Part I. Surgical procedures to correct mandibular prognathism and reshaping of the chin. Oral Surg Oral Med Oral Pathol 1957;10:677–89. Bae SM, Park HS, Kyung HM, Kwon OW, Sung JH. Clinical application of microimplant anchorage. J Clin Orthod 2002;36:298–302. Park JU, Hwang YS. Evaluation of the soft and hard tissue changes after anterior segmental osteotomy on the maxilla and mandible. J Oral Maxillofac Surg 2008;66:98–103.
[13] Kim JR, Son WS, Lee SG. A retrospective analysis of 20 surgically corrected bimaxillary protrusion patients. Int J Adult Orthodon Orthognath Surg 2002;17:23–7. [14] Stoelinga PJ, Leenen RJ, Class II. Anomalies: a coordinated approach to the management of skeletal, dental, and soft tissue problems. J Oral Surg 1981;39:827. [15] Bell WH, Dann JJ. Correction of dentofacial deformities by surgery in the anterior part of the jaws: a study of stability and soft tissue changes. Am J Orthod 1973;64:162. [16] Lanigan DT. Discussion. False aneurysm of the sphenopalatine artery after a Le Fort osteotomy: report of 2 cases. J Oral Maxillofac Surg 2003;61: 524.
Contents lists available at ScienceDirect
Asian Journal of Oral and Maxillofacial Surgery journal homepage: www.elsevier.com/locate/ajoms
Original research
A novel modification in combined Le Fort I and horseshoe osteotomy for posterior repositioning of the maxilla Izumi Yoshioka a,b,∗ , Amit Khanal a , Masaaki Kodama a , Manabu Habu a , Takeshi Nishikawa a , Kenjiro Iwanaga a, Shinya Kokuryo a, Akihiko Basugi a, Sumio Sakoda b, Jinichi Fukuda a, Kazuhiro Tominaga a a b
Division of Maxillofacial Diagnostic and Surgical Science, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, Kitakyushu, Fukuoka, Japan Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Miyazaki 5200 Kihara Kiyotake, Miyazaki, 889-1692, Japan
a r t i c l e
i n f o
Article history: Received 5 December 2010 Received in revised form 19 May 2011 Accepted 30 May 2011 Available online 23 June 2011 Keywords: Le Fort I osteotomy Horseshoe osteotomy Posterior repositioning of maxilla Accuracy
a b s t r a c t Objective: Posterior repositioning of the maxilla using a novel modification in combined Le Fort I and horseshoe osteotomy in bimaxillary surgeries is described and assessed for accuracy. Materials and methods: In this prospective study, posterior repositioning of maxilla was performed in a total of 10 patients where the planned posterior setback was at least 3 mm or greater. In all patients, the maxilla was first osteotomized with Le Fort I and horseshoe osteotomy in addition to a new technique to trim maxillary tuberosity and posterior palatal walls, and followed by bilateral sagittal split ramus osteotomy in the mandible with or without additional genioplasty. Lateral cephalograms were obtained preoperatively and 1 week postoperatively. The changes in upper incisor (U1) and upper molar mesial cusp tip (UMT) were examined. Results: The discrepancy between the planned and actual posterior movement was 0.35 and 0.28 mm at U1 and UMT, respectively. There were no severe complications such as intraoperative haemorrhage, avascular necrosis of the maxilla (partial/total), devitalization of teeth, and oroantral or oronasal fistulas in any of the cases. Conclusions: These results suggest that when greater posterior repositioning of the maxilla is indicated, this newly introduced novel modification in horseshoe osteotomy combined with Le Fort I osteotomy is an effective technique for safety and accuracy. © 2011 Asian Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
1. Introduction Maxillary protrusion is one of the most common dentofacial deformities, especially in Far-East Asian community [1]. Conventionally, maxillary skeletal protrusion used to be treated by orthodontic movements alone or combined surgical and orthodontic treatment consisting in extraction of two maxillary premolars associated with anterior maxillary segmental osteotomy. Although the anterior occlusal result comes out quite good, the esthetic impact is often unsatisfactory in severe maxillary protrusions [2]. Further, these methods do not correct for the generally associated vertical maxillary excess or the first molar class II relationship.
∗ Corresponding author at: University of Miyazaki, Department of Oral and Maxillofacial Surgery, Faculty of Medicine, 5200 Kihara Kiyotake, Miyazaki, 889-1692, Japan. Tel.: +81 985 85 3786; fax: +81 985 85 7190. E-mail address: [email protected] (I. Yoshioka).
Therefore, posterior repositioning of total maxilla using Le Fort I osteotomy is the treatment of choice in severe maxillary protrusion. The posterior movement of maxilla as a single segment after Le Fort I osteotomy is often difficult owing to the interferences of posterior maxillary bone around the great palatine canal and anterior part of pterygoid plates. Thus, removal of maxillary tuberosity and posterior palatal wall, and/or the anterior part of pterygoid plates are often necessary for posterior setbacks greater than 3 mm. Adversely, there are high chances of injuring descending palatine artery (DPA) or pterygoid plexus of veins, which can result in massive intraoperative haemorrhage and potential aseptic necrosis of the maxilla [3,4]. From the literature, there are very few studies regarding posterior movement of the maxilla in total [5,6]. Bell and McBride [7] for the first time introduced horseshoe palatal osteotomy in combination with Le Fort I osteotomy in 1977. Recently, the authors have described a modified technique of horseshoe osteotomy for superior impactions of the maxilla [8]. The biggest advantage of
0915-6992/$ – see front matter © 2011 Asian Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ajoms.2011.05.004
I. Yoshioka et al. / Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176
173
Fig. 1. (a) Diagram shows reduction of maxillary tuberosity in the dentoalveolar component using a round bur to allow posterior movement of the maxilla by carefully protecting the DPA along with palatine vessels in the palatal component. (b) 3-D model image of (a). (c) Anterior margin of the palatal component can be reduced in case of bony interferences between the anterior palatal component and dentoalveolar component during greater posterior setbacks. The periosteum and palatal mucosa is preserved. (d) 3-D model image of (c).
this technique is that it allows high superior impaction of maxilla especially in the posterior segment while preserving the DPA and maintains the nasal chamber volume. The current literature provides very little relevant information regarding posterior movement of the maxilla in total [5,6]. In this prospective study, we have made some novel modifications in our earlier described technique of horseshoe osteotomy for posterior setbacks of the maxilla [8]. Although its indications seem to be limited, this modification can play a role in the treatment of adult dentofacial class II deformity. The purpose of this article is to propose and report on a series of 10 patients who underwent posterior setbacks of their maxillas using the modified technique of combined Le Fort I and horseshoe osteotomy described below. Further, the accuracy of this technique is evaluated and presented.
2. Patients and methods 2.1. Patient selection The subjects were 10 adult Japanese patients referred for surgical correction of dentofacial deformity at Kyushu Dental College Hospital from 2006 to 2008. The patients were selected on basis where the planned posterior setback of maxilla was at least 3 mm or greater. Exclusion criteria were one jaw surgery; periodontal disease judged severe by the surgeon; previous maxillo-mandibular surgery and any history of trauma or craniofacial syndrome. Informed consent was obtained from patients and the study was approved by Kyushu Dental College Hospital. All the 10 patients (1 male, 9 female; age range: 19–25 years; median age 21 years)
underwent Le Fort I and horseshoe osteotomy accompanied by mandibular surgery. They had received pre-surgical orthodontics treatment consisting of decompensation and alignment of dental arch with bilateral maxillary first premolar extractions.
2.2. Surgical technique Nasoendotracheal intubation was followed by local anesthetics infiltration. Soft tissue dissection was performed in the standard fashion, as previously described [9]. Then conventional Le Fort I osteotomy was performed according to that of Bell’s technique [9]. Similarly, horseshoe osteotomy was performed according to our earlier described technique [8]. After horseshoe osteotomy, the dentoalveolar component was mobilized from the palatal component consisting bilateral DPA. To allow posterior setback of the maxilla, bone around maxillary tuberosities was carefully reduced using round bur. The maxillary tuberosities were trimmed carefully to avoid any injury to the DPA, dental roots and palatal mucosa. The palatal component consisting bilateral DPA was not trimmed (Fig. 1a and b). However, when greater setback of the maxilla is desired, bony interferences between the dentoalveolar component and anterior margin of the palatal component makes it difficult for posterior pushback. As earlier described [8], we have been utilizing a technique of further dividing the palatal component into 3 parts through 2 parallel osteotomies from the superior aspect. Osteotomizing the palatal component into 3 parts provide flexibility which helps in higher superior impaction of the dentoalveolar component. This time, we have introduced a simple technique of selectively reduc-
174
I. Yoshioka et al. / Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176
Fig. 2. An illustration showing the shaded areas that can be trimmed for posterior setbacks. The dotted lines represent horseshoe osteotomy with palatal component divided into three parts.
ing the anterior margin of palatal component with a round bur so that the dentoalveolar component can be easily repositioned backwards (Figs. 1c and d and 2). Periosteum and palatal mucosa were preserved. Double splint technique was applied in order to achieve the planned position of osteomized maxilla intraoperatively and fixed with four L-shaped titanium miniplates. In all cases, bilateral sagittal split ramus osteotomy (SSRO) with/without genioplasty was performed following Trauner/Obwegeser’s technique [10] and fixed with 2 semi rigid four-hole titanium miniplates at the anterior mandibular ramus. Both planning and operations were done by two senior surgeons of this department. 2.3. Method of analysis Subjects were evaluated 1-week before surgery (T0), and at postoperative 1 week (T1). Lateral cephalograms were taken with the patient oriented to the Frankfort Horizontal Plane. Reliability of repositioning was performed on lateral cephalograms (Fig. 3). Postoperative changes of the upper 1 (U1) and the upper first molar cusp tip (UMT) from Frankfort horizontal plane were measured immediately after releasing intermaxillary fixation. Discrepancy between prediction and actual horizontal and vertical movement of U1 and UMT were examined. All of these analyses were performed by one of the authors who were blinded to the study. The linear measures on lateral cephalograms used in this study are illustrated in Fig. 3. X- and Y-coordinate measurements were obtained by using a line parallel to the Frankfort horizontal plane for the X coordinate. A perpendicular line was then drawn inter-
Fig. 3. Method of analyzing lateral cephalograms for posterior movement of maxilla using the upper 1 (U1) and the upper molar mesial cusp tip (UMT) in relation with Frankfort plane.
secting the X-coordinate. These X- and Y-coordinated axes were transcribed onto each successive radiograph by superimposition on the “best fit” of sella, nasion, anterior and posterior cranial base landmarks. The relevant points were indicated on the X and Y axes. Movements of these points were represented as linear measurements in millimeters on both the axes. On the X-axis, posterior movement was indicated as a positive value, and anterior movement as a negative value. On the Y-axis, superior movement was indicated as a positive value, while inferior movement as a negative value. The paired t-test was used to identify the skeletal significance of difference between the planned surgical movements and post-surgical changes.Statistical significance was set at P < 0.05.
3. Results There were no severe complications such as intraoperative haemorrhage, avascular necrosis of the maxilla (partial/total), devitalization of teeth and oroantral or oronasal fistulas in any of the cases. The average blood loss was 742.00 mm (SD 330.13) and average operation time was 401.73 min (SD 82.61). Postoperatively, the multi segmented maxilla had a good bony healing as verified from
Table 1 Reliability of posterior repositioning. Case no.
1 2 3 4 5 6 7 8 9 10 Mean ± SD
U1
UMT
Predicted (mm)
Actual (mm)
Discrepancy (mm)
Predicted (mm)
Actual (mm)
Discrepancy (mm)
3.00 3.00 3.00 5.00 3.50 3.00 3.00 3.00 4.50 3.00 3.40 ± 0.70
2.47 3.26 2.84 4.70 3.99 3.56 2.79 2.62 4.73 3.42 3.44 ± 0.77
0.53 0.26 0.16 0.30 0.49 0.56 0.21 0.38 0.23 0.42 0.35 ± 0.14
3.00 3.00 3.00 5.00 3.50 3.00 3.00 3.00 4.50 3.00 3.36 ± 0.70
2.36 3.21 2.88 4.77 3.60 3.46 2.75 2.53 4.62 3.16 3.33 ± 0.77
0.64 0.21 0.12 0.23 0.10 0.46 0.25 0.47 0.12 0.16 0.28 ± 0.17
I. Yoshioka et al. / Asian Journal of Oral and Maxillofacial Surgery 23 (2011) 172–176
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Table 2 Reliability of superior repositioning. Case no.
1 2 3 4 5 6 7 8 9 10 Mean ± SD
U1
UMT
Predicted (mm)
Actual (mm)
Discrepancy (mm)
Predicted (mm)
Actual (mm)
Discrepancy (mm)
4.00 3.00 3.00 5.00 3.00 0 2.00 1.50 1.00 2.00 2.45 ± 1.39
3.65 2.91 1.98 4.00 3.45 −0.28 2.15 1.35 1.10 1.53 2.18 ± 1.26
0.35 0.09 1.02 1.00 0.45 0.28 0.15 0.15 0.10 0.47 0.41 ± 0.33
5.00 2.00 3.50 5.00 3.00 0 3.50 1.50 2.00 5.00 3.05 ± 1.61
4.20 2.23 3.38 5.74 3.05 −0.88 3.50 1.15 1.35 4.52 2.82 ± 1.82
0.80 0.23 0.12 0.74 0.05 0.88 0 0.35 0.65 0.48 0.43 ± 0.31
radiographs and clinical examinations during follow up period of atleast 1 year. 3.1. Accuracy for repositioning of the maxilla Table 1 shows the reliability of posterior repositioning of the maxilla obtained by measuring U1 and the UMT. The mean posterior prediction was 3.36 mm (range 3.0–5.0 mm) with mean actual position being 3.33 mm accounting 0.28 mm as a discrepancy value between the planned and actual maxillary position at UMT. Similarly, the mean superior prediction was 3.05 mm (range 0–5.0 mm) and mean actual position being 2.82 mm with discrepancy value of 0.43 mm at UMT (Table 2). The vertical and horizontal difference between the planned and actual position of the maxilla was not statistically significant. This shows that the maxillas were repositioned nearly to their planned positions during surgery posteriorly as well as superiorly. 4. Discussion Conventionally, orthodontics treatment with bilateral premolar extraction is the most common way of treating maxillary protrusion. Recent advances in orthodontics technique, such as miniscrews allow maximum anchorage and further simplify this procedure [11]. However, orthodontics alone to retract the anterior teeth with bilateral premolar extractions has limitations owing to various factors such as the amount of tooth movement, periodontal status and patient’s age [12]. To overcome these limitations, anterior segmental osteotomy of the maxilla is sometimes recommended. Anterior segmental osteotomy can markedly reduce the treatment period over conventional orthodontics treatment and achieve immediate improvement of the facial profile [13]. However, the anterior segmental osteotomy often has many postoperative sequelae such as necrosis of repositioned anterior segment, devitalization of teeth, and ankylosis of canine, wound dehiscence at the osteotomy site and poor occlusal interdigitation in the canine-premolar region [9,14,15]. Posterior repositioning or setback of maxilla in total using Le Fort I osteotomy is often difficult due to bony interferences at the posterior edge. Hence, bone around the maxillary tuberosity and palatine canal should be reduced for an effective posterior movement. However, there are high chances of injuring descending palatine artery (DPA) during bone trimming leading to massive intraoperative haemorrhage. Further, in cases requiring greater amount of posterior setback even after maxillary trimming, pterygoid plates need to be sectioned and fractured to accommodate the desired setback amount. Although this procedure is rarely indicated, there is good clinical evidence supported by radiographic
documentation that high level pterygoid plate fractures can result in severe complications like haemorrhage and false aneurysm formation [4,16]. Our novel modification in combination of Le Fort I and horseshoe osteotomy for posterior repositioning of the maxilla is versatile in its design. This modification allows posterior setback as well as superior impactions without compromising on the DPA, nasal chamber volume and posterior airway space. It provides a greater posterior movement of maxilla unlike that offered by anterior segmental osteotomy, which is limited to the width of the extracted teeth or by a single segment Le Fort I osteotomy. The very fact that this technique provides space by the reduction of maxillary tuberosity and third molar (extracted socket) allows greater posterior pushbacks. We have achieved a maximum posterior repositioning of 4.77 mm at UMT by this technique with high accuracy of the planned posterior maxillary movement. While treating deformities having maxillary excess, not only posterior setbacks but superior impactions are often needed as seen in our reported cases. This modified technique is able to serve the both purposes of posterior and superior repositioning of the maxilla. In conclusion, extensive removal of maxillary tuberosity and posterior palatal wall could be safely obtained with this newly described novel modification in horseshoe osteotomy. Thus, when posterior repositioning of the maxilla is indicated, combining Le Fort I with horseshoe osteotomy is an available useful technique for safety and accuracy. We hope that this technique will be of great benefit while treating maxillary excesses, especially in the Far-East Asian population.
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