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Ultrasonic orthognathic surgery: enhancements to established osteotomies
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Int. J. Oral Maxillofac. Surg. 2012; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2012.12.004, available online at http://www.sciencedirect.com
Clinical Paper Orthognathic Surgery
Ultrasonic orthognathic surgery: enhancements to established osteotomies
R. Gillesa, T. Couvreurb, S. Dammousa a
Department of Oral and Maxillofacial Surgery, Clinique de Espe´rance, 447 rue St. Nicolas, 4420 Montegne´e, Belgium; b Department of Radiology, Clinique de Espe´rance, 447 rue St. Nicolas, 4420 Montegne´e, Belgium
R. Gilles, T. Couvreur, S. Dammous: Ultrasonic orthognathic surgery: enhancements to established osteotomies. Int. J. Oral Maxillofac. Surg. 2012; xxx: xxx–xxx. # 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. The use of a novel ultrasonic osteotome enabled the authors to modify wellestablished orthognathic osteotomies to more favourably address the anatomy. For this purpose, they utilized a powerful ultrasonic device with tissue-selective cutting characteristics that was originally developed for spinal osteotomies and nerve decompression (BoneScalpelTM by Misonix Inc., Farmingdale, NY, USA). Its straight ultrasonic blade was adapted for dual action, and a soft protective element was added. The product modifications and the related changes regarding maxillary and mandibular osteotomies are explained in detail. A series of 83 patients underwent orthognathic surgery with the BoneScalpel ultrasonic osteotome. All osteotomies within this study group were performed purely ultrasonically and without the auxiliary use of reciprocating saws or rotary burrs. The complications, alveolar nerve impairment and bad splits were assessed. To assess the quality of the lingual osteotomies and pterygomaxillary separation, three-dimensional scanning was performed on 30 patients. In conclusion, the BoneScalpelTM ultrasonic osteotome enabled improved control over orthognathic osteotomies and resulted in significant reductions in the occurrence of nerve impairment and bad splits.
Ultrasonic systems have been used for surgical soft tissue removal for several decades. Typical applications include laparoscopic dissection,1 resection of head and neck tumours,2 lipoplasty3 and the aspiration of spinal and intracranial tumours.4 The concept of ultrasonic bone dissection was envisioned as early as the 1960s by McFall et al.5 In 2001, Vercellotti introduced an angled piezoelectric short saw, which presented benefits for osteotomies during oral surgery without causing damage to adjacent soft tissue.6,7 A 0901-5027/000001+07 $36.00/0
number of Vercellotti-type devices have since been launched on the market (Piezosurgery 3, Piezosurgery Medical, Piezon Master, Variosurg, and Piezotome 2) and are often referred to as piezoelectric, piezosurgical or piezotome systems. Numerous comparative studies have been performed to determine their safety and efficacy in bone surgery.8,9 Multiple studies have evaluated the feasibility of piezoelectric surgery with Vercellotti-type devices as a substitute for the use of conventional saws and burrs in orthognathic surgery. Overall, these studies reported
Key words: orthognathic surgery; orthognathics; ultrasonic osteotome; BoneScalpel; piezoelectric surgery; piezosurgery; piezotome; bone cutting; osteosurgery; osteotomy; osteotome; ultrasonic curette. Accepted for publication 5 December 2012
favourable reductions in blood loss, operative oedema and nerve injuries at the cost of an increased time investment due to insufficient cutting power for the mandible and the need for the auxiliary use of traditional burrs or saws.10–15 In 2003, Hadeishi et al. reported the safe use of a non-Vercellotti-type ultrasonic bone curette (Sonopet by Miwatec Co., Inagi, Japan) for anterior clinoidectomies and opening the internal auditory canal without causing damage to the surrounding structures.16 Ueki et al. used this instrument in 2004 to perform pterygoid
# 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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process fractures without damaging the surrounding tissues in 14 adults.17 Garzino-Demo et al. used it for resecting mandibular tumours involving the inferior alveolar nerve.18 The most recent system on the market is the BoneScalpelTM ultrasonic osteotome (Misonix, Inc., Farmingdale, NY, USA). Originally developed for neurosurgical nerve decompression and spinal osteotomies, this device promises to combine the benefits of previous piezoelectric devices with improved ergonomics and cutting efficiency. The device features a straight blade with distally bevelled edges that can cleave into bone. In this approach, osseous or calcified tissue is transected by the recurring mechanical impacts of the blade edge at high and constant ultrasonic repetitions of 22,500 purely longitudinal strokes per second. This results in the controlled compression and splitting of rigid, crystalline structures, while soft and elastic tissues are generally able to deform temporarily to maintain their integrity. Sanborn et al. reported favourably on the safety and efficacy of the BoneScalpel ultrasonic osteotome after performing laminectomies on an ovine model in 2011.19 Parker et al. recently presented a case series of 11 patients using the ultrasonic osteotome to perform osteoplastic laminoplasty during the resection of intradural spinal cord pathology.20 Based on ergonomic and performance requirements for advanced orthognathic osteotomies, the authors selected the BoneScalpel ultrasonic osteotome for further study and collaborated with the manufacturer to optimize an existing blade for use in maxillofacial procedures. Materials and methods
A novel ultrasonic osteotome (BoneScalpel1 by Misonix Inc., Farmingdale, NY) was used to perform maxillary and mandibular osteotomies. The standard blade has a straight configuration, is 20 mm long, and 1.0 mm thick. The distal tip has a rounded shape with bevelled surfaces forming a blunt forward-cutting edge. A central channel ensures the proper distribution of roomtemperature irrigant to all cutting surfaces to provide cooling and lubrication, even when the blade is fully engaged in bone. The authors collaborated with the manufacturer to introduce several modifications. Blunt serrations allow bone dissection with one lateral side of the blade, while the contralateral side remains smooth for safe manoeuvring within the oral cavity. Depth markers are etched into the blade surface at 3, 5, 10, and 15 mm to gauge blade
Fig. 1. Modified ultrasonic blade for orthognathic surgery.
insertion. A soft, protective element made out of silicone and placed at the junction with the handpiece prevents burns to lips or mucosa. The blade length was subsequently extended to 30 mm to accommodate anatomical needs in the maxilla and mandible better (Fig. 1). 83 patients (40 males and 43 females) who were scheduled to undergo orthognathic surgery were prospectively enrolled in this study between August 2009 and June 2012 with the consent of the local ethics committee. The patients’ mean age at the time of surgery was 29 years (range 13–65 years). Patients with a previous history of orthognathic surgery were excluded from the study. The indications for surgery included the presence of dimorphisms in 71 patients and symptoms of sleep apnea in 12 patients. The authors performed 49 Le Fort I osteotomies, 19 maxillary expansions, 5 mandibular expansions, 102 sagittal split osteotomies, and 8 genioplasties. In addition, they performed 40 bi-maxillary procedures. The 20 mm blade was utilized for all osteotomies in patients 1–67, and the 30 mm blade version was used in patients 68–83. The BoneScalpel ultrasonic osteotome operates at a nominal, nonmodulated frequency of 22.5 kHz, and the amplitude of vibration ranges from 35 to 300 mm. While amplitude settings of 1–10 are available, the authors observed that a setting of 7 was well suited to the range of bone qualities encountered. Room temperature 0.9% saline solution is delivered through an integrated peristaltic pump that moves fluid through the central hand piece channel to the blade. The irrigant flow rate is adjustable from 15 to 80 ml/min, which corresponds to console settings of 20– 100%. Irrigation at setting 100% was chosen to cool the bone and clean the surgical site. All of the surgical procedures were performed by two senior surgeons while the patients were under general anaesthesia with nasal intubation. The third molars had been removed at least 9 months prior to the orthognathic procedure.
Fig. 2. Coronal and 3D-reconstructed model views of the mandible.
A control scan with a 2 mm thickness (GE Brightspeed) was obtained 2 days postoperatively, in accordance with recommendations made by the ethics committee. The authors examined the ideal bilateral separation between the maxillary tuberosity and the pterygoid plates. The mandible was digitally isolated from the maxilla and skull to observe the design of the split with OSIRIX Software (Fig. 2). The operative time was evaluated objectively with OPERA Software. Patients were questioned about the presence or absence of abnormal sensitivity. Outpatient follow-ups were performed at 15 days, 2 months and up to 3 years after each procedure. Fracture lines were classified and compared with those reported in the literature. For the bilateral sagittal split osteotomy (BSSO), the subperiosteal preparations and dissections were performed as usual. The osteotomy was initiated at 458 on the lingual ramus side. The nonactive rigid blade in combination with the serrated profile allowed us to determine the geometry and consistency of the osseous surface (Figs. 3 and 4). According to the
Fig. 3. Cutting the lingual ramus.
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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Fig. 6. Cutting the tuberosity and the anterior sinus wall. Fig. 4. Cutting the lingual ramus and the oblique line.
penetrate the lateral nasal wall over the entire length of the septum (Figs. 7 and 8). An Obwegeser chisel was applied to all pterygomaxillary sutures, although the disjunction primarily occurred during the use of the ultrasonic device. The maxillary down-fracture was easily obtained with improved control due to an absence of bleeding.
preoperative scans, the blade tip penetrated on the oblique line deeply into the cortical bone at a 308 angle in the direction of the nerve canal without fear of harming the alveolar nerve (Figs. 4 and 5). The vertical inferior osteotomy was performed to a level below the basilar region. The split manoeuvre was easily performed with manual rotation of the osteotomes. For the Le Fort I osteotomies, the subperiosteal preparations and dissections were performed in the usual fashion through sulcular incisions. The straight ultrasonic blade was pulled around the maxillary tuberosity without visual control. The blade was inserted deeper than would be possible with a saw, without fear of causing haemorrhage, to weaken the pterygomaxillary junction and the posterior sinus wall (Fig. 6). The blade was then brought back to the anterior sinus wall to
All 183 osteotomies in 83 patients in this study were performed with the use of the BoneScalpel ultrasonic osteotome. Its ability to engage bone deeply while maintaining an efficient cutting speed made the use of traditional power instruments, such as saws or burrs, unnecessary. The blade design, with its integrated central channel, was effective in providing irrigant at room temperature to all cutting surfaces, including those that were deep in the bone. Subjectively, the authors noted clear reductions in swelling and haematoma formation. In addition, the authors
Fig. 5. Cutting the oblique line of the mandible.
Fig. 7. Cutting the nasal wall.
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observed the complete absence of dental lesions, haemorrhage, facial palsy and perforations of the nasal mucosa. Only 2 cases were observed to have hypoesthesia (1.96%) of the intra-alveolar nerve. The patients were older and treated for symptoms of sleep apnea. An unsatisfactory split occurred only once (0.98%) during the first use of the 30 mm blade due to insufficient power transmission, which was rectified in subsequent cases. This patient had no disturbance of the nerve. Three patients who underwent sagittal split osteotomy developed an infection on the sagittal side (2.94%) due to poor dental hygiene but did not suffer any significant consequences. Control scans performed after 2 days in patients 53–83 showed different patterns of lingual splitting according to the Plooij et al.21 classification and different patterns of pterygomaxillary separation according to Robinson and Hendy.22 The results for mandibular splitting were 64.8% using Hunsuck’s definition and zero bad splits (Table 1). For the maxilla, 58.3% showed perfect separation of the pterygomaxillary junction without fracture of the pterygoid plates (Table 2).
Results Discussion
Various complications can occur during conventional orthognathic surgery. Kramer et al. prospectively evaluated 1000 patients with conventional Le Fort I osteotomies and reported that 6.4% experienced complications.23 Telzrow et al. examined complications in a series of 1264 patients who underwent conventional sagittal split osteotomy procedures and reported that: 2.8% of patients developed an infection requiring an extraoral incision and drainage; the inferior alveolar nerve was inadvertently cut in 2.1%; 1.2% suffered bleeding complications; and 0.9% experienced an unfavourable split.24 Landes et al. reported the following results in a conventional series of 86 patients: 1.5% of the patients developed an infection; 6% had alveolar nerve damage; 3% developed haemorrhages; 8% experienced unfavourable splits; and 1.5% of the patients had foreign objects left in situ.13,14 In contrast, fewer complications have been reported when piezoelectric devices are used. Landes et al. reported the following results from a piezo-osteotomy study involving 50 patients: 8% experienced unfavourable splits due to incomplete osteotomies with a Vercellotti-type unit; no foreign objects were left in situ; and no
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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Fig. 8. Lateral, medial and septal osteotomies.
patients experienced facial nerve palsy, haemorrhage, macroscopic nerve damage or osteomyelitis. In a series of 50 patients in whom the Mectron was used, Landes et al. concluded
that individualized osteotomy designs are possible and that weakening of the pterygomaxillary sutures occurred, although auxiliary chisels were required in 100% of cases targeting the nasal septum and
Table 1. Classification of mandibular fracture lines. LSS1 LSS2 LSS3 LSS4 N
20 mm
%
30 mm
%
Total
Plooij
18 8 4 0 30
60% 26.6% 13.4% 0%
17 4 3 0 24
70% 16.6% 12.4% 0%
64.8% 22.2% 13% 0% 54
51.25% 13.75% 32.5% 2.5% 80
LSS1, vertical pattern of fracture line to inferior border of the mandible (‘true’ Hunsuck); LSS2, horizontal pattern of fracture line to posterior border of the ramus; LSS3, fracture line through the mandibular canal to the inferior border of the mandible; LSS4, other patterns such as a buccal plate fracture or a bad split.
lateral nasal walls and 33% of those targeting the pterygoid processes. Maxillary down-fractures were significantly reduced, and haemorrhage was successfully avoided. Sagittal mandibular osteotomies required the auxiliary use of a saw in 15% of the cases and were considerably more time consuming. The clinical courses and reossification were unobtrusive, and alveolar inferior nerve sensitivity was retained in 98% of the surgical subjects versus 84% of the controls 3 months after the operation.13,14 For sagittal osteotomies, the method used by Beziat et al. began with cuts of the cortical bone using a round burr, followed by a Vercellotti-type piezosurgical device that was used during the entire sagittal splitting osteotomy. The size of the piezotomy area increased with experience to avoid bad splitting,12 however, from the present authors’ point of view, Beziat et al. did not perform a complete piezoelectric osteotomy. In the study of Gruber et al., in which 7 patients received BSSRO, only 1 patient (7.1%) reported full recovery of sensitivity 7 months after surgery, although this patient complained of a ‘different feeling’ in the area of the left chin compared with the right side.11 Through the utilization of the BoneScalpel ultrasonic osteotome, the authors most striking observation from 83 patients was a significant reduction in bleeding, which resulted in a clean operative field. Thus, osteotomies of the maxilla, particularly the posterior, were safe and risk free. The placement of retractors can now be optimized to avoid stretching of the nerves because of the inherent soft tissue-sparing characteristic of the BoneScalpel ultrasonic osteotome. Moreover, this procedure can be performed with four hands. When performing a BSSO, a preoperative scan precisely displays the lingula and the position of the nerve canal into the ramus. Plooij et al. used cone beam computed tomography (CT) scans to analyze the fracture line for BBSSO in 40 consecutive
Table 2. Comparison of maxillary fracture patterns in the literature.
HLF LLF MLF PCS + PTI PCS + HLF PCS + LLF Total PCS N
20 mm
30 mm
%
0% 9% 4.6% 59.1% 4.6% 22.7% 86.4% 22
7.7% 19.2% 0% 57.7% 3.8% 11.6% 73% 26
4.1% 14.6% 2.08% 58.3% 4.1% 16.6% 79.1% 48
Lanigan micro-saw
Reinick curved Ost
Laster Shark-fin
Laster Obwegeser
Koichiro Sonopet
30% 50%
39.2% 24.3%
19%
70% 4%
81%
25%
100%
20%
24
100% 10
20% 10
16.2% 32
74
HLF, high-level fracture; LLF, low-level fracture; MLF, multiple fractures; PCS, pterygoid completely separate from the maxilla; PTI, pterygoid plates intact.
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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Ultrasonic orthognathic surgery patients who underwent BBSSO advancements, and the results highlighted four paths of the split on the lingual side of the ramus. They concluded that the split pattern was influenced by the length of the medial osteotomy21 (Table 1). Yu and Wong used three-dimensional CT scans to measure the mandibles of 40 Taiwanese patients and found that the mean distance from the anterior border to the antilingula was 17.7 2.89 mm, with a maximum distance of 28.1 mm and a minimum of 10.9 mm. These authors concluded that medial horizontal osteotomy should be performed 5 mm superior to the antilingula and should be extended 4–8 mm posterior to the antilingula.25 While the 20 mm serrated BoneScalpel blade was long enough for most patients, it proved to be too short for some. Based on a morphological analysis, a 30 mm version was developed and used for the last 15 patients (Table 1). Yu and Wong localized the dental nerve near the vertical cut and found that the distance between the mandibular canal and the buccal plate at the second molar was 7.2 1.47 mm, with a maximum distance of 10.6 mm and a minimum of 4.4 mm. Moreover, the distance from the mandibular canal to the lower border at the second molar was 7.6 1.69 mm, with a maximum distance of 12 mm and a minimum of 3.3 mm. The straight configuration and the stiffness of the BoneScalpel blade serve to increase the accuracy of the osteotomy. Compared with conventional saws and burrs, the new ultrasonic blade shows a minimal tendency to deviate from the intended path or walk on bone surfaces. This allows for the placement of the nonactive blade in the correct position prior to activating the ultrasound and engaging the bone, which is not possible with the saw. Moreover, the working position is different from the drill or the saw and appears to be more ergonomic, as the blade does not bend during use. The primary purpose of the serrations added to the lateral side of the blade was to enable the cutting motion along the ramus to remain forward rather than sideways and in accordance with the proposed 458 tilt angle. The 458 angle is critical for initiating the fracture itself, as there is no significant cancellous bone present in this portion of the mandible. A traditional osteotomy is characterized by a steep, increasing angle from the lingual towards the oblique position. In contrast, the BoneScalpel ultrasonic osteotome allows one to continue seamlessly from the lingual ramus towards the
oblique at the same 458 angle. Therefore, the cutting force that is introduced at the posterior ramus is better transmitted into the bone, which improves the quality of the lingual osteotomy. For the horizontal osteotomy, the blade is angled inward towards the nerve canal. The use of the ultrasonic blade is more accurate than the rotary burr or reciprocating saw. The sagittal saw blade is far from rigid, and its lateral flexibility introduces random movements and straying of the saw tip, which make it difficult to maintain the required perpendicular position. Moreover, the risk of slippage with the conventional saw blade is high. In contrast, the new procedure utilizing an ultrasonic osteotome enables the osseous cutting to be more precise and allows for an improved adaption to the anatomy. The tissue-specific cutting resulting from the use of ultrasound technology enables deeper blade insertion for both horizontal and vertical osteotomies, without fear of causing nerve trauma, unlike conventional methods. This is further facilitated by the marker lines on the ultrasonic blade. The propagation of the ultrasonic wave into the cancellous layer facilitates splitting. The thickness of the blade allows for an improved osteotomy line, in accordance with the available width of chisels used to perform the splitting. As a result of these improvements, the vertical osteotomy is safer, as the position of the nerve is preoperatively ascertained from the imaging scan. With the ultrasonic osteotome, it is possible to slip below the basilar level to reach at least half its width without the risk of damaging the facial nerve. The contralateral vertical osteotomy can easily be achieved by having the surgeon switch sides. In contrast, the reciprocating saw requires caution to maintain a superficial cut and avoid penetrating too deeply into the basilar level, as the inferior alveolar nerve could be located just medial to the cortex. The kerf is approximately 1.5 mm, which enables osteotomes and a Cryer elevator to be introduced easily above the basal level. This also allows for force uniformity during the split. With this approach, the osteotomies are more accurate and deeper, and the forces required for splitting are much smaller. This also reduces the risk of bad splits because the osteotomies can be well defined according to the individual patient’s anatomy and pathology, and this may result in the use of osteotomies in more difficult cases, such as cases of asymmetry, older patients requiring reconstruction or patients with apnea.
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The most frequent surgical morbidity associated with BSSO is damage to the inferior alveolar nerve caused by direct mechanical injury, postoperative oedema or compression injury after fixation. Nakagawa et al. reported that damage was also initiated during periosteal dissection on the medial side of the ascending ramus.26 Unlike the saw, the straight blade does not require a large dissection for the placement of the retractor, and minimal subperiosteal elevation decreases this risk. The method described by Gruber et al. requires the use of two types of angulated inserts. They concluded that this method was more time consuming,11 and in the current study, using the BoneScalpel ultrasonic osteotome, there was no need to change inserts during use, as the entire procedure was performed utilizing the straight blade. For Le Fort I osteotomies, the blade can be inserted safely without any visual control behind the level of the pterygoid. Closed scissors are currently only used to verify the disjunction with the contact finger at the palate. Cheung et al. showed that the presence of maxillary third molars influences the transverse angulation of the posterior vertical cut. In his series of 30 Asian dry skulls, he identified the location for safe osteotomy. This posterior type of osteotomy can also be performed with different instrumentation.27 In a study that examined 50 cadaver heads, the advantages of using a micro-oscillating saw were reported.28,29 The present authors noted adequate pterygoid disjunction in their series, and this result was confirmed in the group of 30 patients who were given immediate postoperative CT scans (Table 2). Osteotomy of the pillars and nasal septum can be performed using the 30 mm blade without tearing the nasal mucosa. In contrast to the technique described by Landes et al., osteotomies of the nasal septum and lateral nasal walls were initiated at a depth of 20 or 30 mm. The study by Li et al. showed that the average distance from the piriform rim to the descending palatine canal was 38.4 mm in men and 34.6 mm in women.30 Furthermore, Cheung et al. recommended 23 mm as the minimal safety guideline for the medial cut.27 Using the line markers on the 20 mm and 30 mm blades, the authors did not risk touching the artery, and can confirm that the osteotomy easily reached the inner sinus walls, which significantly facilitated the maxillary down-fracture. When the down-fracture was initiated, the authors were able to complete the
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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osteotomies safely with the BoneScalpel, especially in the posterior region (i.e. near the emergence of the artery). By entering deeper into the anterior sinus wall, they effectively widened the osteotomy and needed to consider a gap of 1.5 mm for the cephalometric preparation. Compared with the rotary burr or sagittal saw, the osteotomy line for the BoneScalpel is more regular. In posterior maxillary impaction, the ostectomy of the posterior wall is safer with BoneScalpel. The authors think that a comparative study of the quality of osteotomies performed using conventional saws and chisels or ultrasonic blades could be achieved on fresh cadaver heads. Minimally invasive procedures (endoscopic) would also benefit from these advances. In conclusion, recent improvements in ultrasonic surgery have proved to be important for advanced orthognathic osteotomies, and the use of ultrasonic instruments, with their associated benefits, is no longer limited to dental surgery. The authors were able to adapt a more powerful ultrasonic device, the Misonix BoneScalpel, for use in orthognathic surgery. This tool allowed them to improve the techniques for performing maxillary and mandibular osteotomies because they were able to take advantage of the improved control over bone cuts, an enhanced comprehension of the anatomy, and the knowledge that the blade would spare soft tissues. This technique resulted in a higher efficiency in the operating room when performing orthognathic osteotomies. This preliminary report justifies the further study of various parameters listed in the objective criteria with a longer patient follow-up period. Funding
None. Competing interests
None declared. Ethical approval
Approval was obtained from the ethics committee of CHC, Liege. Acknowledgments. The authors would like to thank the engineering team, which consisted of Christian Ritter, Dan Void and Alex Darian, for helping us to adapt the blades. They would also like to
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Ultrasonic orthognathic surgery 27. Cheung LK, Fung SC, Samman N. Posterior maxillary anatomy: implications for Le Fort I osteotomy. Int J Oral Maxillofac Surg 1998;27:346–51. 28. Lanigan DT, Guest P. Alternative approaches to pterygomaxillary separation. Int J Oral Maxillofcac Surg 1993;22:131–8. 29. Lanigan DT, Loewy J. Postoperative computed tomography scan study of the
pterygomaxillary separation during the Le Fort I osteotomy using a micro-oscillating saw. J Oral Maxillofac Surg 1995;53: 1161–6. 30. Li KK, Merar JG, Alexander A. Localisation of the descending palatine in relation to the Le Fort I osteotomy. J Oral Maxillofac Surg 1996;54:822–5.
Address: R. Gilles 6 rue des Fagnes 4020 Lie`ge Belgium Tel: +32 475 273891; Fax: +32 4 2249292 E-mail: [email protected]
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Int. J. Oral Maxillofac. Surg. 2012; xxx: xxx–xxx http://dx.doi.org/10.1016/j.ijom.2012.12.004, available online at http://www.sciencedirect.com
Clinical Paper Orthognathic Surgery
Ultrasonic orthognathic surgery: enhancements to established osteotomies
R. Gillesa, T. Couvreurb, S. Dammousa a
Department of Oral and Maxillofacial Surgery, Clinique de Espe´rance, 447 rue St. Nicolas, 4420 Montegne´e, Belgium; b Department of Radiology, Clinique de Espe´rance, 447 rue St. Nicolas, 4420 Montegne´e, Belgium
R. Gilles, T. Couvreur, S. Dammous: Ultrasonic orthognathic surgery: enhancements to established osteotomies. Int. J. Oral Maxillofac. Surg. 2012; xxx: xxx–xxx. # 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Abstract. The use of a novel ultrasonic osteotome enabled the authors to modify wellestablished orthognathic osteotomies to more favourably address the anatomy. For this purpose, they utilized a powerful ultrasonic device with tissue-selective cutting characteristics that was originally developed for spinal osteotomies and nerve decompression (BoneScalpelTM by Misonix Inc., Farmingdale, NY, USA). Its straight ultrasonic blade was adapted for dual action, and a soft protective element was added. The product modifications and the related changes regarding maxillary and mandibular osteotomies are explained in detail. A series of 83 patients underwent orthognathic surgery with the BoneScalpel ultrasonic osteotome. All osteotomies within this study group were performed purely ultrasonically and without the auxiliary use of reciprocating saws or rotary burrs. The complications, alveolar nerve impairment and bad splits were assessed. To assess the quality of the lingual osteotomies and pterygomaxillary separation, three-dimensional scanning was performed on 30 patients. In conclusion, the BoneScalpelTM ultrasonic osteotome enabled improved control over orthognathic osteotomies and resulted in significant reductions in the occurrence of nerve impairment and bad splits.
Ultrasonic systems have been used for surgical soft tissue removal for several decades. Typical applications include laparoscopic dissection,1 resection of head and neck tumours,2 lipoplasty3 and the aspiration of spinal and intracranial tumours.4 The concept of ultrasonic bone dissection was envisioned as early as the 1960s by McFall et al.5 In 2001, Vercellotti introduced an angled piezoelectric short saw, which presented benefits for osteotomies during oral surgery without causing damage to adjacent soft tissue.6,7 A 0901-5027/000001+07 $36.00/0
number of Vercellotti-type devices have since been launched on the market (Piezosurgery 3, Piezosurgery Medical, Piezon Master, Variosurg, and Piezotome 2) and are often referred to as piezoelectric, piezosurgical or piezotome systems. Numerous comparative studies have been performed to determine their safety and efficacy in bone surgery.8,9 Multiple studies have evaluated the feasibility of piezoelectric surgery with Vercellotti-type devices as a substitute for the use of conventional saws and burrs in orthognathic surgery. Overall, these studies reported
Key words: orthognathic surgery; orthognathics; ultrasonic osteotome; BoneScalpel; piezoelectric surgery; piezosurgery; piezotome; bone cutting; osteosurgery; osteotomy; osteotome; ultrasonic curette. Accepted for publication 5 December 2012
favourable reductions in blood loss, operative oedema and nerve injuries at the cost of an increased time investment due to insufficient cutting power for the mandible and the need for the auxiliary use of traditional burrs or saws.10–15 In 2003, Hadeishi et al. reported the safe use of a non-Vercellotti-type ultrasonic bone curette (Sonopet by Miwatec Co., Inagi, Japan) for anterior clinoidectomies and opening the internal auditory canal without causing damage to the surrounding structures.16 Ueki et al. used this instrument in 2004 to perform pterygoid
# 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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process fractures without damaging the surrounding tissues in 14 adults.17 Garzino-Demo et al. used it for resecting mandibular tumours involving the inferior alveolar nerve.18 The most recent system on the market is the BoneScalpelTM ultrasonic osteotome (Misonix, Inc., Farmingdale, NY, USA). Originally developed for neurosurgical nerve decompression and spinal osteotomies, this device promises to combine the benefits of previous piezoelectric devices with improved ergonomics and cutting efficiency. The device features a straight blade with distally bevelled edges that can cleave into bone. In this approach, osseous or calcified tissue is transected by the recurring mechanical impacts of the blade edge at high and constant ultrasonic repetitions of 22,500 purely longitudinal strokes per second. This results in the controlled compression and splitting of rigid, crystalline structures, while soft and elastic tissues are generally able to deform temporarily to maintain their integrity. Sanborn et al. reported favourably on the safety and efficacy of the BoneScalpel ultrasonic osteotome after performing laminectomies on an ovine model in 2011.19 Parker et al. recently presented a case series of 11 patients using the ultrasonic osteotome to perform osteoplastic laminoplasty during the resection of intradural spinal cord pathology.20 Based on ergonomic and performance requirements for advanced orthognathic osteotomies, the authors selected the BoneScalpel ultrasonic osteotome for further study and collaborated with the manufacturer to optimize an existing blade for use in maxillofacial procedures. Materials and methods
A novel ultrasonic osteotome (BoneScalpel1 by Misonix Inc., Farmingdale, NY) was used to perform maxillary and mandibular osteotomies. The standard blade has a straight configuration, is 20 mm long, and 1.0 mm thick. The distal tip has a rounded shape with bevelled surfaces forming a blunt forward-cutting edge. A central channel ensures the proper distribution of roomtemperature irrigant to all cutting surfaces to provide cooling and lubrication, even when the blade is fully engaged in bone. The authors collaborated with the manufacturer to introduce several modifications. Blunt serrations allow bone dissection with one lateral side of the blade, while the contralateral side remains smooth for safe manoeuvring within the oral cavity. Depth markers are etched into the blade surface at 3, 5, 10, and 15 mm to gauge blade
Fig. 1. Modified ultrasonic blade for orthognathic surgery.
insertion. A soft, protective element made out of silicone and placed at the junction with the handpiece prevents burns to lips or mucosa. The blade length was subsequently extended to 30 mm to accommodate anatomical needs in the maxilla and mandible better (Fig. 1). 83 patients (40 males and 43 females) who were scheduled to undergo orthognathic surgery were prospectively enrolled in this study between August 2009 and June 2012 with the consent of the local ethics committee. The patients’ mean age at the time of surgery was 29 years (range 13–65 years). Patients with a previous history of orthognathic surgery were excluded from the study. The indications for surgery included the presence of dimorphisms in 71 patients and symptoms of sleep apnea in 12 patients. The authors performed 49 Le Fort I osteotomies, 19 maxillary expansions, 5 mandibular expansions, 102 sagittal split osteotomies, and 8 genioplasties. In addition, they performed 40 bi-maxillary procedures. The 20 mm blade was utilized for all osteotomies in patients 1–67, and the 30 mm blade version was used in patients 68–83. The BoneScalpel ultrasonic osteotome operates at a nominal, nonmodulated frequency of 22.5 kHz, and the amplitude of vibration ranges from 35 to 300 mm. While amplitude settings of 1–10 are available, the authors observed that a setting of 7 was well suited to the range of bone qualities encountered. Room temperature 0.9% saline solution is delivered through an integrated peristaltic pump that moves fluid through the central hand piece channel to the blade. The irrigant flow rate is adjustable from 15 to 80 ml/min, which corresponds to console settings of 20– 100%. Irrigation at setting 100% was chosen to cool the bone and clean the surgical site. All of the surgical procedures were performed by two senior surgeons while the patients were under general anaesthesia with nasal intubation. The third molars had been removed at least 9 months prior to the orthognathic procedure.
Fig. 2. Coronal and 3D-reconstructed model views of the mandible.
A control scan with a 2 mm thickness (GE Brightspeed) was obtained 2 days postoperatively, in accordance with recommendations made by the ethics committee. The authors examined the ideal bilateral separation between the maxillary tuberosity and the pterygoid plates. The mandible was digitally isolated from the maxilla and skull to observe the design of the split with OSIRIX Software (Fig. 2). The operative time was evaluated objectively with OPERA Software. Patients were questioned about the presence or absence of abnormal sensitivity. Outpatient follow-ups were performed at 15 days, 2 months and up to 3 years after each procedure. Fracture lines were classified and compared with those reported in the literature. For the bilateral sagittal split osteotomy (BSSO), the subperiosteal preparations and dissections were performed as usual. The osteotomy was initiated at 458 on the lingual ramus side. The nonactive rigid blade in combination with the serrated profile allowed us to determine the geometry and consistency of the osseous surface (Figs. 3 and 4). According to the
Fig. 3. Cutting the lingual ramus.
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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Ultrasonic orthognathic surgery
Fig. 6. Cutting the tuberosity and the anterior sinus wall. Fig. 4. Cutting the lingual ramus and the oblique line.
penetrate the lateral nasal wall over the entire length of the septum (Figs. 7 and 8). An Obwegeser chisel was applied to all pterygomaxillary sutures, although the disjunction primarily occurred during the use of the ultrasonic device. The maxillary down-fracture was easily obtained with improved control due to an absence of bleeding.
preoperative scans, the blade tip penetrated on the oblique line deeply into the cortical bone at a 308 angle in the direction of the nerve canal without fear of harming the alveolar nerve (Figs. 4 and 5). The vertical inferior osteotomy was performed to a level below the basilar region. The split manoeuvre was easily performed with manual rotation of the osteotomes. For the Le Fort I osteotomies, the subperiosteal preparations and dissections were performed in the usual fashion through sulcular incisions. The straight ultrasonic blade was pulled around the maxillary tuberosity without visual control. The blade was inserted deeper than would be possible with a saw, without fear of causing haemorrhage, to weaken the pterygomaxillary junction and the posterior sinus wall (Fig. 6). The blade was then brought back to the anterior sinus wall to
All 183 osteotomies in 83 patients in this study were performed with the use of the BoneScalpel ultrasonic osteotome. Its ability to engage bone deeply while maintaining an efficient cutting speed made the use of traditional power instruments, such as saws or burrs, unnecessary. The blade design, with its integrated central channel, was effective in providing irrigant at room temperature to all cutting surfaces, including those that were deep in the bone. Subjectively, the authors noted clear reductions in swelling and haematoma formation. In addition, the authors
Fig. 5. Cutting the oblique line of the mandible.
Fig. 7. Cutting the nasal wall.
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observed the complete absence of dental lesions, haemorrhage, facial palsy and perforations of the nasal mucosa. Only 2 cases were observed to have hypoesthesia (1.96%) of the intra-alveolar nerve. The patients were older and treated for symptoms of sleep apnea. An unsatisfactory split occurred only once (0.98%) during the first use of the 30 mm blade due to insufficient power transmission, which was rectified in subsequent cases. This patient had no disturbance of the nerve. Three patients who underwent sagittal split osteotomy developed an infection on the sagittal side (2.94%) due to poor dental hygiene but did not suffer any significant consequences. Control scans performed after 2 days in patients 53–83 showed different patterns of lingual splitting according to the Plooij et al.21 classification and different patterns of pterygomaxillary separation according to Robinson and Hendy.22 The results for mandibular splitting were 64.8% using Hunsuck’s definition and zero bad splits (Table 1). For the maxilla, 58.3% showed perfect separation of the pterygomaxillary junction without fracture of the pterygoid plates (Table 2).
Results Discussion
Various complications can occur during conventional orthognathic surgery. Kramer et al. prospectively evaluated 1000 patients with conventional Le Fort I osteotomies and reported that 6.4% experienced complications.23 Telzrow et al. examined complications in a series of 1264 patients who underwent conventional sagittal split osteotomy procedures and reported that: 2.8% of patients developed an infection requiring an extraoral incision and drainage; the inferior alveolar nerve was inadvertently cut in 2.1%; 1.2% suffered bleeding complications; and 0.9% experienced an unfavourable split.24 Landes et al. reported the following results in a conventional series of 86 patients: 1.5% of the patients developed an infection; 6% had alveolar nerve damage; 3% developed haemorrhages; 8% experienced unfavourable splits; and 1.5% of the patients had foreign objects left in situ.13,14 In contrast, fewer complications have been reported when piezoelectric devices are used. Landes et al. reported the following results from a piezo-osteotomy study involving 50 patients: 8% experienced unfavourable splits due to incomplete osteotomies with a Vercellotti-type unit; no foreign objects were left in situ; and no
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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Fig. 8. Lateral, medial and septal osteotomies.
patients experienced facial nerve palsy, haemorrhage, macroscopic nerve damage or osteomyelitis. In a series of 50 patients in whom the Mectron was used, Landes et al. concluded
that individualized osteotomy designs are possible and that weakening of the pterygomaxillary sutures occurred, although auxiliary chisels were required in 100% of cases targeting the nasal septum and
Table 1. Classification of mandibular fracture lines. LSS1 LSS2 LSS3 LSS4 N
20 mm
%
30 mm
%
Total
Plooij
18 8 4 0 30
60% 26.6% 13.4% 0%
17 4 3 0 24
70% 16.6% 12.4% 0%
64.8% 22.2% 13% 0% 54
51.25% 13.75% 32.5% 2.5% 80
LSS1, vertical pattern of fracture line to inferior border of the mandible (‘true’ Hunsuck); LSS2, horizontal pattern of fracture line to posterior border of the ramus; LSS3, fracture line through the mandibular canal to the inferior border of the mandible; LSS4, other patterns such as a buccal plate fracture or a bad split.
lateral nasal walls and 33% of those targeting the pterygoid processes. Maxillary down-fractures were significantly reduced, and haemorrhage was successfully avoided. Sagittal mandibular osteotomies required the auxiliary use of a saw in 15% of the cases and were considerably more time consuming. The clinical courses and reossification were unobtrusive, and alveolar inferior nerve sensitivity was retained in 98% of the surgical subjects versus 84% of the controls 3 months after the operation.13,14 For sagittal osteotomies, the method used by Beziat et al. began with cuts of the cortical bone using a round burr, followed by a Vercellotti-type piezosurgical device that was used during the entire sagittal splitting osteotomy. The size of the piezotomy area increased with experience to avoid bad splitting,12 however, from the present authors’ point of view, Beziat et al. did not perform a complete piezoelectric osteotomy. In the study of Gruber et al., in which 7 patients received BSSRO, only 1 patient (7.1%) reported full recovery of sensitivity 7 months after surgery, although this patient complained of a ‘different feeling’ in the area of the left chin compared with the right side.11 Through the utilization of the BoneScalpel ultrasonic osteotome, the authors most striking observation from 83 patients was a significant reduction in bleeding, which resulted in a clean operative field. Thus, osteotomies of the maxilla, particularly the posterior, were safe and risk free. The placement of retractors can now be optimized to avoid stretching of the nerves because of the inherent soft tissue-sparing characteristic of the BoneScalpel ultrasonic osteotome. Moreover, this procedure can be performed with four hands. When performing a BSSO, a preoperative scan precisely displays the lingula and the position of the nerve canal into the ramus. Plooij et al. used cone beam computed tomography (CT) scans to analyze the fracture line for BBSSO in 40 consecutive
Table 2. Comparison of maxillary fracture patterns in the literature.
HLF LLF MLF PCS + PTI PCS + HLF PCS + LLF Total PCS N
20 mm
30 mm
%
0% 9% 4.6% 59.1% 4.6% 22.7% 86.4% 22
7.7% 19.2% 0% 57.7% 3.8% 11.6% 73% 26
4.1% 14.6% 2.08% 58.3% 4.1% 16.6% 79.1% 48
Lanigan micro-saw
Reinick curved Ost
Laster Shark-fin
Laster Obwegeser
Koichiro Sonopet
30% 50%
39.2% 24.3%
19%
70% 4%
81%
25%
100%
20%
24
100% 10
20% 10
16.2% 32
74
HLF, high-level fracture; LLF, low-level fracture; MLF, multiple fractures; PCS, pterygoid completely separate from the maxilla; PTI, pterygoid plates intact.
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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Ultrasonic orthognathic surgery patients who underwent BBSSO advancements, and the results highlighted four paths of the split on the lingual side of the ramus. They concluded that the split pattern was influenced by the length of the medial osteotomy21 (Table 1). Yu and Wong used three-dimensional CT scans to measure the mandibles of 40 Taiwanese patients and found that the mean distance from the anterior border to the antilingula was 17.7 2.89 mm, with a maximum distance of 28.1 mm and a minimum of 10.9 mm. These authors concluded that medial horizontal osteotomy should be performed 5 mm superior to the antilingula and should be extended 4–8 mm posterior to the antilingula.25 While the 20 mm serrated BoneScalpel blade was long enough for most patients, it proved to be too short for some. Based on a morphological analysis, a 30 mm version was developed and used for the last 15 patients (Table 1). Yu and Wong localized the dental nerve near the vertical cut and found that the distance between the mandibular canal and the buccal plate at the second molar was 7.2 1.47 mm, with a maximum distance of 10.6 mm and a minimum of 4.4 mm. Moreover, the distance from the mandibular canal to the lower border at the second molar was 7.6 1.69 mm, with a maximum distance of 12 mm and a minimum of 3.3 mm. The straight configuration and the stiffness of the BoneScalpel blade serve to increase the accuracy of the osteotomy. Compared with conventional saws and burrs, the new ultrasonic blade shows a minimal tendency to deviate from the intended path or walk on bone surfaces. This allows for the placement of the nonactive blade in the correct position prior to activating the ultrasound and engaging the bone, which is not possible with the saw. Moreover, the working position is different from the drill or the saw and appears to be more ergonomic, as the blade does not bend during use. The primary purpose of the serrations added to the lateral side of the blade was to enable the cutting motion along the ramus to remain forward rather than sideways and in accordance with the proposed 458 tilt angle. The 458 angle is critical for initiating the fracture itself, as there is no significant cancellous bone present in this portion of the mandible. A traditional osteotomy is characterized by a steep, increasing angle from the lingual towards the oblique position. In contrast, the BoneScalpel ultrasonic osteotome allows one to continue seamlessly from the lingual ramus towards the
oblique at the same 458 angle. Therefore, the cutting force that is introduced at the posterior ramus is better transmitted into the bone, which improves the quality of the lingual osteotomy. For the horizontal osteotomy, the blade is angled inward towards the nerve canal. The use of the ultrasonic blade is more accurate than the rotary burr or reciprocating saw. The sagittal saw blade is far from rigid, and its lateral flexibility introduces random movements and straying of the saw tip, which make it difficult to maintain the required perpendicular position. Moreover, the risk of slippage with the conventional saw blade is high. In contrast, the new procedure utilizing an ultrasonic osteotome enables the osseous cutting to be more precise and allows for an improved adaption to the anatomy. The tissue-specific cutting resulting from the use of ultrasound technology enables deeper blade insertion for both horizontal and vertical osteotomies, without fear of causing nerve trauma, unlike conventional methods. This is further facilitated by the marker lines on the ultrasonic blade. The propagation of the ultrasonic wave into the cancellous layer facilitates splitting. The thickness of the blade allows for an improved osteotomy line, in accordance with the available width of chisels used to perform the splitting. As a result of these improvements, the vertical osteotomy is safer, as the position of the nerve is preoperatively ascertained from the imaging scan. With the ultrasonic osteotome, it is possible to slip below the basilar level to reach at least half its width without the risk of damaging the facial nerve. The contralateral vertical osteotomy can easily be achieved by having the surgeon switch sides. In contrast, the reciprocating saw requires caution to maintain a superficial cut and avoid penetrating too deeply into the basilar level, as the inferior alveolar nerve could be located just medial to the cortex. The kerf is approximately 1.5 mm, which enables osteotomes and a Cryer elevator to be introduced easily above the basal level. This also allows for force uniformity during the split. With this approach, the osteotomies are more accurate and deeper, and the forces required for splitting are much smaller. This also reduces the risk of bad splits because the osteotomies can be well defined according to the individual patient’s anatomy and pathology, and this may result in the use of osteotomies in more difficult cases, such as cases of asymmetry, older patients requiring reconstruction or patients with apnea.
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The most frequent surgical morbidity associated with BSSO is damage to the inferior alveolar nerve caused by direct mechanical injury, postoperative oedema or compression injury after fixation. Nakagawa et al. reported that damage was also initiated during periosteal dissection on the medial side of the ascending ramus.26 Unlike the saw, the straight blade does not require a large dissection for the placement of the retractor, and minimal subperiosteal elevation decreases this risk. The method described by Gruber et al. requires the use of two types of angulated inserts. They concluded that this method was more time consuming,11 and in the current study, using the BoneScalpel ultrasonic osteotome, there was no need to change inserts during use, as the entire procedure was performed utilizing the straight blade. For Le Fort I osteotomies, the blade can be inserted safely without any visual control behind the level of the pterygoid. Closed scissors are currently only used to verify the disjunction with the contact finger at the palate. Cheung et al. showed that the presence of maxillary third molars influences the transverse angulation of the posterior vertical cut. In his series of 30 Asian dry skulls, he identified the location for safe osteotomy. This posterior type of osteotomy can also be performed with different instrumentation.27 In a study that examined 50 cadaver heads, the advantages of using a micro-oscillating saw were reported.28,29 The present authors noted adequate pterygoid disjunction in their series, and this result was confirmed in the group of 30 patients who were given immediate postoperative CT scans (Table 2). Osteotomy of the pillars and nasal septum can be performed using the 30 mm blade without tearing the nasal mucosa. In contrast to the technique described by Landes et al., osteotomies of the nasal septum and lateral nasal walls were initiated at a depth of 20 or 30 mm. The study by Li et al. showed that the average distance from the piriform rim to the descending palatine canal was 38.4 mm in men and 34.6 mm in women.30 Furthermore, Cheung et al. recommended 23 mm as the minimal safety guideline for the medial cut.27 Using the line markers on the 20 mm and 30 mm blades, the authors did not risk touching the artery, and can confirm that the osteotomy easily reached the inner sinus walls, which significantly facilitated the maxillary down-fracture. When the down-fracture was initiated, the authors were able to complete the
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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osteotomies safely with the BoneScalpel, especially in the posterior region (i.e. near the emergence of the artery). By entering deeper into the anterior sinus wall, they effectively widened the osteotomy and needed to consider a gap of 1.5 mm for the cephalometric preparation. Compared with the rotary burr or sagittal saw, the osteotomy line for the BoneScalpel is more regular. In posterior maxillary impaction, the ostectomy of the posterior wall is safer with BoneScalpel. The authors think that a comparative study of the quality of osteotomies performed using conventional saws and chisels or ultrasonic blades could be achieved on fresh cadaver heads. Minimally invasive procedures (endoscopic) would also benefit from these advances. In conclusion, recent improvements in ultrasonic surgery have proved to be important for advanced orthognathic osteotomies, and the use of ultrasonic instruments, with their associated benefits, is no longer limited to dental surgery. The authors were able to adapt a more powerful ultrasonic device, the Misonix BoneScalpel, for use in orthognathic surgery. This tool allowed them to improve the techniques for performing maxillary and mandibular osteotomies because they were able to take advantage of the improved control over bone cuts, an enhanced comprehension of the anatomy, and the knowledge that the blade would spare soft tissues. This technique resulted in a higher efficiency in the operating room when performing orthognathic osteotomies. This preliminary report justifies the further study of various parameters listed in the objective criteria with a longer patient follow-up period. Funding
None. Competing interests
None declared. Ethical approval
Approval was obtained from the ethics committee of CHC, Liege. Acknowledgments. The authors would like to thank the engineering team, which consisted of Christian Ritter, Dan Void and Alex Darian, for helping us to adapt the blades. They would also like to
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Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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Address: R. Gilles 6 rue des Fagnes 4020 Lie`ge Belgium Tel: +32 475 273891; Fax: +32 4 2249292 E-mail: [email protected]
Please cite this article in press as: Gilles R, et al. Ultrasonic orthognathic surgery: enhancements to established osteotomies, Int J Oral Maxillofac Surg (2013), http://dx.doi.org/10.1016/j.ijom.2012.12.004
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