Osteogenic uni- or bilateral form of the guided rapid maxillary expansion

Journal of Cranio-Maxillo-Facial Surgery (2010) 38, 160e165 Ó 2009 European Association for Cranio-Maxillo-Facial Surgery doi:10.1016/j.jcms.2009.03.011, available online at http://www.sciencedirect.com

Osteogenic uni- or bilateral form of the guided rapid maxillary expansion K. AL-OUF, Head of the Oral and Maxillofacial Surgery Unit1, C. KRENKEL, Professor and Head of Oral and Maxillofacial Surgery Department2, M. Y. HAJEER, Senior Lecturer in Orthodontics3, S. SAKKA, Senior Lecturer in Oral and Maxillofacial Surgery3 1 3

Central Police Hospital, Damascus, Syria; 2 Paracelsus University, Muellner Hauptstr 48, 5020 Salzburg, Austria; University of Albaath Dental School, Hamah, Syria

SUMMARY. Surgically assisted rapid palatal expansion is an important treatment procedure in patients with constricted maxillae. Several surgical methods have been proposed to expand the maxilla bilaterally. A new technique was developed for performing a symmetric or asymmetric maxillary expansion guided by the stability of the mid-palatal area employing two osteotomy cuts on either side of mid-palatal suture. A Hyrax-type expansion device was used post-operatively. Seventeen patients were included in the study (9 males, 8 females) with a mean age of 30.7 years. Inter-canine and inter-molar widths were evaluated at three assessment intervals: before treatment (T1), immediately after appliance removal (T2) and at six months follow-up (T3). Between T1 and T2, a mean expansion of 7.1 and 9.9 mm was achieved at the canine and molar areas, respectively. The amount of relapse measured between T2 and T3 was minimal (a mean value of 0.35 and 0.8 mm at the canine and molar areas, respectively). Asymmetric expansion was performed in 6 patients who exhibited unilateral skeletal constriction at the initial assessment and these cases appeared stable at T3. The surgical approach described in the current study enabled rapid maxillary expansion of unilateral and bilateral skeletal constriction cases effectively and with good stability. Ó 2009 European Association for Cranio-Maxillo-Facial Surgery

Keywords: rapid maxillary expansion, palatal osteogenesis, asymmetric expansion

Steinhauser described a surgical technique in which an osteotomy similar to a Le Fort I osteotomy was performed for immediate maxillary widening. Bony segments were moved apart and the resultant space was filled by transplanted autologous bone (Steinhauser, 1972). When reviewing the literature, several methods have been proposed to perform osteotomies on the maxillary complex for maxillary expansion. One of these methods included an osteotomy extending from the piriform aperture to the maxillary tuberosity. Expansion could be then executed by ordinary skeletal screws (Timms and Vero, 1981). Another method was dependent on an osteotomy in the zygomatic process in conjunction with an osteotomy in the palatal area (Kaban, 1984), whereas Zoeller and Ullrich performed an osteotomy in zygomatico-maxillary process area in addition to the mid-palatal suture (Zoeller and Ullrich, 1991). Glassman et al. performed an osteotomy in the faciomaxillary wall starting from the naso-frontal suture and ending at the maxillary tuberosity (Glassman et al., 1984). When Schimming et al. applied this method on their patients, a case with a fracture in the alveolar ridge of the maxillary bone was recorded due to the ossification of the mid-palatal suture (Schimming et al., 2000). Bell and Epker performed a surgical cut similar to Le Fort I osteotomy, in which all the facial bony structures were cut in addition to the osteotomy that was performed in the mid-palatal suture area (Bell and Epker, 1976). Then expansion was accomplished gradually and bone

INTRODUCTION Expansion of the upper jaw cannot be performed by the use of traditional orthodontic appliances (e.g. Haas or Hyrax appliances) when the mid-palatal suture becomes totally ossified (Moss, 1986). Therefore, osteotomies are indicated to facilitate expansion movements and to avoid overloading the teeth which may be accompanied by bone resorption (Moss, 1968). Hippocrates was the first to write about the constricted upper jaw (Lindorf, 2006). From 1730, several appliances were utilized to expand the maxilla. In 1860, Dr Angell accomplished a conservative and non-surgical maxillary expansion procedure (Angell, 1860). Derichsweiler described the same procedure in 1950 (Derichsweiler, 1953, 1958). ‘Rapid’ maxillary expansion was first used and popularized by Haas who employed this technique in the treatment of patients with constricted maxillary jaws (Haas, 1961, 1980). For a long time, it has been thought that the median palatal suture is the area most resistant to maxillary expansion (Morselli, 1997). It has been shown that other sutures might play a similar role to the median palatal suture (Isaacson and Murphy, 1964; Isaacson et al., 1969). Several studies demonstrated that the fronto-maxillary, zygomatico-maxillary and pterygo-maxillary sutures were resistant areas for maxillary expansion procedures (Lines, 1975; Bell and Jacobs, 1979). One study stressed that the maximum resistance to maxillary expansion came from the zygomatic arch (Wertz and Dreskin, 1977). 160

Osteogenic uni- or bilateral form of the guided rapid maxillary expansion 161

deposited in a way similar to the osteogenesis procedures described by Ilizarov in medicine (the treatment of bone lengthening of ends) (Ilizarov, 1990; McCarthy et al., 1992). Moreselli used a minor surgical procedure to perform maxillary expansion and thought that the mid-palatal suture did not play a primary role when expanding the maxilla (Morselli, 1997). When Mommaerts et al. applied a similar approach using endoscopically assisted corticotomies to perform transpalatal osteodistraction, they found that the operative time as well as both percentage and nature of complications were similar to those experienced with ‘open-sky transpalatal distraction’ with less pronounced oedema (Mommaerts et al., 2008). Stroemberg and Holm, after a longitudinal follow-up of patients with maxillary expansion, found that the inter-molar width was increased by a mean amount of 7.1 mm, whereas the inter-canine width was increased a mean amount of 4.8 mm. They found that the mid-palatal suture might remain unossified for a long time (Stromberg and Holm, 1995). Lindorf applied selective weakening procedures to the facial bones and used mini-plates to create what could be called ‘semi-stabilization’. In addition, he employed inter-maxillary elastics to guide the expansion procedure (Lindorf, 2006). It has been noted from the literature review that several surgical approaches to maxillary expansion as well as several opinions about the most suitable lines of osteotomies have been proposed. The aim of the current paper is to describe and evaluate a modification of the conventional method of surgically assisted rapid maxillary expansion by the application of two osteotomies on either side of the mid-palatal suture which is followed by ordinary maxillary widening and bone formation. This technique is referred to as ‘‘Osteogenic Uni- or Bilateral Form of Rapid Maxillary Expansion’’ (OUF-RME). MATERIALS AND METHODS Subjects Seventeen patients (8 females and 9 males) with skeletal transverse discrepancies in the maxilla were treated between 2005 and 2008 at the Department of Oral and Maxillofacial Surgery at Paracelsus Medical University, Salzburg (Austria) as well as at the Department of Oral and Maxillofacial Surgery at Police Hospital in Damascus (Syria). The average patient age was 30.7 years. Mandibular prognathism was diagnosed in 13 patients whereas maxillary retrognathism occurred in 12 patients, with 8 patients being diagnosed as having both skeletal abnormalities. All patients exhibited skeletal posterior crossbite either uni- or bilaterally. Orthodontic brackets were placed on the anterior teeth in 14 cases pre-operatively, whereas 3 cases just underwent orthodontic treatment post-operatively. Ligation options between the upper six teeth depended on the treatment plan. A Hyrax-type expansion appliance was used with four bands on the upper first premolars and upper first molars.

Fig. 1 e Frontal view showing the lines of osteotomies on the maxillary complex.

Fig. 2 e Occlusal view of the maxillary complex showing the bilateral osteotomies extending from the midpoint between the upper lateral and the canine (on the right side) and between the upper central and lateral incisor (on the left side). These osteotomies are extended to the posterior border of the maxillary complex.

OUF-RME surgical technique The procedure was performed under general anaesthesia and local infiltration with a vasoconstrictor (Adrenaline, 1:100,000 concentration) which was applied on both sides of the oral vestibule. Oral intubation was used for general anaesthesia since the surgical osteotomies were performed through the nasal cavity floor and not from the palatal area. The palatal mucosa was kept intact throughout the procedure. An incision was made in the mucosal membrane and the periosteum in the depth of the vestibule. This incision extended from the first molar on the right side to the first molar on the other side. Soft tissues were dissected at the canine fossa as well as the maxillary tuberosity. Dissection was also made along the floor of the nasal cavity towards the soft palate. Intra-operatively, the patient was given intravenous antibiotics.

162 Journal of Cranio-Maxillo-Facial Surgery

Fig. 3 e Lateral views. A e right view, B e left view. The lateral osteotomy line extends from the lower margin of the pirifrom aperture of the nasal cavity towards the posterior margin of the maxillary complex.

Fig. 4 e This intra-oral photograph shows the OUF-RME lines of osteotomies in the anterior region of the maxilla. It can be seen that two vertical osteotomies extend from the horizontal osteotomies towards the interdental alveoli between the central and lateral incisors bilaterally.

The anterior nasal spine area was not cut during the procedure; therefore, there was no possibility of injuring the naso-palatal nerve or artery. This was followed by a separation of the main facial pillar zones e the frontal process area and the zygomatic process area of the maxillary bone using a surgical saw, and the pterygo-maxillary process area by a Kawamoto chisel (Figs. 1e3a and 4b). Osteotomy was performed on both sides of the mid-palatal suture in the floor of the nasal cavity starting from the posterior border and continuing towards the anterior border of the piriform aperture. The osteotomy extended between teeth 11 and 12 or 12 and 13 on the right hand side, and between teeth 21 and 22 or 22 and 23 on the left hand side (Fig. 4). A long saw blade was used for this procedure and injury to the palatal mucosa was avoided. A fine chisel was used to separate the alveolar ridge bone between the anterior teeth. A bony separator device was used to completely mobilise the bone on both sides of the osteotomy line (Fig. 5). In this manner, the midpalatal area remained stable because of its attachment to the vomer as well as the mid-nasal areas. This stable mid-palatal area played a major role in guiding the subsequent maxillary expansion. Great care was taken to ensure that the bilateral maxillary segments were properly mobilised on both sides in order to facilitate the expansion movements. Finally, flaps were replaced and sutured. Following the surgical

Fig. 5 e A bony separator device is used to mobilise the bone completely and thoroughly.

intervention, the Hyrax-type appliance was cemented onto the upper first premolars and molars (14, 24, 16 and 26). The screw was turned four times (each turn is equivalent of 0.25 mm) with an initial expansion of 1 mm intra-operatively. To avoid post-surgical oedema the patients were asked not to blow their nose and to breathe gently (Tuinzing et al., 2005). The protocol of the following activations of the skeletal expansion device was similar to the other rapid maxillary expansion techniques after a latency period of one week. The expansion procedure was continued until good transverse posterior relationships were achieved. The Hyrax-type device was maintained for an additional three months for retention. Orthodontic treatment was continued until the patients achieved their final planned occlusion. Assessment method Alginate impressions were taken at the beginning of treatment (T1), immediately after appliance removal (T2) and six months following appliance removal (T3). Study model analysis included the measurement of inter-canine and inter-molar widths at the three assessment intervals using digital calipers (Fig. 6). RESULTS This technique showed good results in expanding the maxilla, which was guided through the stable positioning

Osteogenic uni- or bilateral form of the guided rapid maxillary expansion 163

of the mid-palatal area (Table 1). When measuring the inter-canine width, a mean expansion of 7.1 mm was achieved, whereas the expansion at the molar area reached a mean value of 9.9 mm. After an average follow-up of six months, there was a mean decrease of 0.35 mm in the inter-canine width, whereas the relapse at the molar area reached a mean value of 0.8 mm. In general, the current study showed that a mean net expansion of 6.7 mm and 9.1 mm can be achieved at the canine and molar areas, respectively, when the OUF-RME was

employed. It should be noted that asymmetric expansion was carried out in 6 patients who exhibited unilateral skeletal constriction at the initial assessment. The stability of the mid-palatal area aided in stabilising upper teeth on their relative positions on arch circumference and moving the required teeth (which are in a posterior crossbite) laterally. In this way, we were able to treat unilateral skeletal constriction cases as well as bilateral constriction cases effectively and accurately. Figs. 7e10 present a skeletal Class III malocclusion in a patient aged 22 years who was treated by the OUFRME technique. At the beginning of treatment, the patient presented with a bilateral crossbite related to maxillary skeletal constriction (Fig. 7). A Hyrax-type RME appliance was tried-in (Fig. 8) and brackets were applied on the upper anterior teeth (Fig. 9). Following the completion of RME, the patient presented a satisfactory maxillary width (Fig. 10). The patient underwent retention for three months and a comprehensive fixed appliance treatment was commenced afterwards. The speed of maxillary expansion using this method appeared greater than that of other rapid maxillary techniques dependant on a single osteotomy along the midpalatal suture. The average expansion time was 17 days. No complications were observed such as haemorrhage, infection, hyper-mobility and asymmetry with the exception of post-surgical swelling which was common with such surgical interventions. DISCUSSION By using this technique, osteogenesis occurs at the sites of distraction of the bony segments of the maxilla. Expansion can be guided through the stable position of the mid-palatal suture area. This design of osteotomies enables the orthodontist to choose any of the two sides

Fig. 6 e Measurements performed on study models. IC: Intercanine, IM: Intermolar.

Table 1 e Sample characteristics, inter-canine and inter-molar widths at assessment intervals Case

1* 2 3 4* 5* 6 7 8 9* 10 11 12* 13 14* 15 16 17 Mean SD

Sex

F F M M F M M F F M M F F M F M M

Age

Inter-canine width (mm) at

Inter-molar width (mm) at

T1

T2

T2

T1

T3

29 23 35 31 35 20 27 26 28 30 46 52 37 27 24 31 22

19 27.5 25 24.5 25.5 20.5 20 28 23.5 23.5 22.5 24.5 28 21 20.5 27 24

25.5 31.5 34 30.5 32 28 27 35.5 31 32.5 29.5 32 36.5 28 28.5 32 31.5

6.5 4 9 6 6.5 7.5 7 7.5 7.5 9 7 7.5 8.5 7 8 5 7.5

25 30.5 34 30 32 27.5 27 35.0 30.5 32.5 29 31.5 35.5 27 28.5 33 31

30.7

23.8 2.9

30.9 2.9

7.1 1.3

30.5 2.9

Relapse

T1

T2

T2

0.5 1.0 0.0 0.5 0.0 0.5 0.0 0.5 0.5 0.0 0.5 0.5 1.0 1.0 0.0 1.0 0.5

33 34.5 40 38.5 39 33 35.5 39.5 38 40.5 41 39 41 35.5 33.5 36 40

43.5 41 52 49 48.5 45.5 44.5 50.5 48.5 48.5 52 48 50.5 47 42 47.5 49

10.5 6.5 11.5 10.5 9.5 12.5 9 11 10.5 8 11 9 9.5 11.5 8.5 11.5 9

43.0 40 51 48.5 48 43.5 44 49.5 48 47 51.5 47 49 47 41.5 47.5 47

0.5 1.0 1.0 0.5 0.5 2.0 0.5 1.0 0.5 1.5 0.5 1.0 1.5 0.0 0.5 0.0 2.0

0.35 0.49

37.5 2.8

47.5 3.2

9.9 1.5

46.6 3.2

0.8 0.6

T1: Before treatment, T2: immediately after appliance removal, T3: at six-month follow-up. * Asymmetric expansion was performed through the stable mid-palatal area.

T1

T3

Relapse

164 Journal of Cranio-Maxillo-Facial Surgery

Fig. 7 e Pre-surgical intra-oral photograph showing the initial malocclusion which was characterised by a Class III skeletal relationship as well as skeletal maxillary constriction.

Fig. 9 e Brackets were placed on the upper anterior teeth (from canine to canine). This was done to enable the surgeon to perform a unilateral expansion when needed.

Fig. 10 e Post-expansion intra-oral photograph showing the final result with satisfactory upper inter-molar and inter-premolar widths.

Fig. 8 e Pre-surgical intra-oral photograph showing an occlusal view of the Hyrax-type RME device when it was tried-in. No cementation was done at this stage.

of the maxillary segments to be ligated to the central part of the maxillary bone (which carries two to four incisors). Therefore, expansion can be directed towards the right or left side of the patient’s maxilla (i.e. unilateral expansion), an approach which has not been well evaluated in the literature (Stromberg and Holm, 1995; Morselli, 1997; Schimming et al., 2000). In the current study, the mean expansion achieved at the canine and molar areas exceeded that documented in other studies (Stromberg and Holm, 1995; Morselli, 1997; Schimming et al., 2000). The procedure appeared stable when measured in the anterior and posterior segments of the maxilla and the mean value of relapse seemed to be less than that reported in earlier studies (Stromberg and Holm, 1995; Schimming et al., 2000). Despite performing double osteotomies, good stability can be attributed to the presence of the mid-palatal area which enhanced the post-expansion stability of the moved segments, in addition to the preservation of the naso-palatal neurovascular bundle which improved the blood supply to the bony segments and enhanced osteogenesis at the areas of distraction. It should be noted that the measurements performed in the current study were based on study models which re-

flected the positions of the crowns before and after the surgically assisted expansion. However, good stability of the posterior teeth in the long-term is dependent on achieving proper axial inclination at the end of treatment which was not evaluated in the current study. This limitation could have been overcome by evaluating frontal cephalograms at the three assessment intervals (Doruk et al., 2004). OUF-RME may facilitate any further orthognathic procedures, restrict the surgical intervention to the upper jaw only, or it may eliminate the need for surgical correction. During the joint treatment planning, the surgeon should discuss with the orthodontist the possibility of conducting such procedure. The nasal cavity size and nasal breathing improve with this technique. Regarding external nasal changes, OUF-RME does not affect nasal aesthetics. The philtrum does not change and no increase in the width of the columella is found. This is because para-saggital expansion does not cause stretching of soft tissues that comprise the philtrum area. This aspect need to be addressed and evaluated objectively in future studies when the OUF-RME is used. This technique is very useful for performing rapid palatal expansion in all skeletally narrow maxillae with the exception of those cases with severely convergent roots between the central and lateral incisors or between the laterals and canines. In such cases, the operator should seek other techniques or may be obliged to ask the

Osteogenic uni- or bilateral form of the guided rapid maxillary expansion 165

orthodontist to perform some pre-surgical space creation for interdental osteotomies. CONCLUSION The OUF-RME has been shown to be effective in performing uni- or bilateral rapid maxillary expansion in patients with constricted maxillary bases. The achieved expansion has been shown to be stable during follow-up. References Angell EH: Treatment of irregularities of the permanent or adult tooth. Dental Cosmos 1: 540e547, 1860 Bell WH, Epker BN: Surgical-orthodontic expansion of the maxilla. Am J Orthod 70(5): 517e528, 1976 Bell WH, Jacobs JD: Surgical-orthodontic correction of horizontal maxillary deficiency. J Oral Surg 37(12): 897e902, 1979 Derichsweiler H: Die Gaumennaht Erweiterung. Fortschr Kieferorthop 14: 405e415, 1953 Derichsweiler H: Die Gaumennaht Erweiterung. Stuttghart: Hansa Verlag, 1958 Doruk C, Bicakci AA, Basciftci FA, Agar U, Babacan H: A comparison of the effects of rapid maxillary expansion and fan-type rapid maxillary expansion on dentofacial structures. Angle Orthod 74(2): 184e194, 2004 Glassman AS, Nahigian SJ, Midway JM, Aronowitz HI: Conservative surgical orthdontic adult rapid palatal expansion: sixteen cases. Am J Orthod 86: 207e213, 1984 Haas AJ: Rapid palatal expansion of the maxillary dental arch and nasal cavity by opening the midfacial sutures. Angle Orthod 31: 73e90, 1961 Haas AJ: Long-term posttreatment evaluation of rapid palatal expansion. Angle Orthod 50(3): 189e217, 1980 Ilizarov GA: Clinical application of the tension-stress effect for limb lengthening. Clin Orthop Relat Res 250: 8e26, 1990 Isaacson RJ, Murphy D: Some effects of rapid maxillary expansion in cleft lip and palate patients. Angle Orthod 34: 143e154, 1964 Isaacson RJ, Wood JL, Ingram AH: Forces produced by rapid maxillary expansion. Angle Orthod 34: 256e269, 1969 Kaban LB: Surgical orthdontic correction of transverse maxillary deficiency: a simplified approach, discussion. Plast Reconstr Surg 73: 67e68, 1984 Lindorf H: Die chirurgisch gesteuerte maxillare expansion (GME) durch selektive Schwachung der Gesichtspfeiler. ZMK 22: 6e20, 2006

Lines PA: Adult rapid maxillary expansion with corticotomy. Am J Orthod 67(1): 44e56, 1975 McCarthy JG, Schreiber J, Karp N, Thorne CH, Grayson BH: Lengthening the human mandible by gradual distraction. Plast Reconstr Surg 89(1): 1e8, 1992 Mommaerts MY, Collado J, Mareque BJ: Morbidity related to ‘‘endocorticotomies’’ for transpalatal osteodistraction. J Craniomaxillofac Surg 36(4): 198e202, 2008 Morselli PG: Surgical maxillary expansion: a new minimally invasive technique. J Craniomaxillofac Surg 25(2): 80e84, 1997 Moss JP: Rapid expansion of the maxillary arch. II. Indications for rapid expansion. J Pract Orthod 2: 215e223, 1968 Moss JP: Rapid expansion of the maxillary arch. I. J Pract Orthod 2: 165e171, 1986 Schimming R, Feller KU, Herzmann K, Eckelt U: Surgical and orthodontic rapid palatal expansion in adults using Glassman’s technique: retrospective study. Br J Oral Maxillofac Surg 38(1): 66e69, 2000 Steinhauser EW: Midline splitting of the maxilla for correction of malocclusion. J Oral Surg 30(6): 413e422, 1972 Stromberg C, Holm J: Surgically assisted, rapid maxillary expansion in adults. A retrospective long-term follow-up study. J Craniomaxillofac Surg 23(4): 222e227, 1995 Timms DJ, Vero D: The relationship of rapid maxillary expansion to surgery with special reference to midpalatal synostosis. Br J Oral Surg 19(3): 180e196, 1981 Tuinzing DB, Greebe RB, Dorenbos J, Van Der Kwast WAM: Surgical orthodontics: diagnosis and treatment, Amsterdam: Harry Ransom Humanities Research Center, 2005 Wertz R, Dreskin M: Midpalatal suture opening: a normative study. Am J Orthod 71(4): 367e381, 1977 Zoeller J, Ullrich H: Die Kombinierte chirurgischkieferorthopadische Gaumennahterweiterung im Erwachsenenalter. Fortschr Kieferorthop 52: 61e65, 1991

Dr K. AL-OUF P.O. Box 25821 Damascus Syria Tel.: +963 115419706 Fax: +963 112221843 E-mail: [email protected] Paper received 9 November 2008 Accepted 28 March 2009