- Email: [email protected]
Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study
YBJOM-5464;
No. of Pages 7
ARTICLE IN PRESS Available online at www.sciencedirect.com
ScienceDirect British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study D. Rossi a , M. Romano a , L. Karanxha b , C. Baserga c , A. Russillo c , S. Taschieri b,e , M. Del Fabbro b,d,∗ , A.B. Giannì c , A. Baj a a
Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Maxillo-Facial and Dental Unit, Fondazione Ca’ Granda IRCCS Ospedale Maggiore Policlinico Milan, Italy b Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Milan, Italy c Università degli Studi di Milano, Maxillo-Facial and Dental Unit, Fondazione Ca’ Granda IRCCS Ospedale Maggiore Policlinico Milan, Italy d Dental Clinic, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy e Faculty of Dental Surgery, I.M Sechenov First Moscow State Medical University Accepted 12 July 2018
Abstract The only cutting technique used for osteotomies in orthognathic surgery for many years has been a saw, but recently piezoelectric surgery has been introduced as a possible alternative. The aim of this study was to find out if piezoelectric surgery can be more comfortable for patients having orthognathic surgery. A total of 25 patients with dentofacial deformities (seven male and 18 female), were treated from January 2016 to September 2017. In 11 patients, osteotomies were made using a conventional saw, while in 14 a piezoelectric device was used. The variables assessed were: operating time, postoperative swelling, postoperative pain, and cutaneous sensitivity of the upper and lower lips. The duration of operation for the piezosurgery group was significantly longer than that for controls, but the patients had less swelling at all follow-up visits, and the difference was significant at the 30-day follow-up (p = 0.045). Those who had piezosurgery had significantly less pain at the three-day follow up (p = 0.035). There was a significant difference in cutaneous sensitivity only for the right side of the upper lip and only at the one-day follow-up. We conclude that piezoelectric surgery offers some advantages in lessening swelling and the perception of pain after orthognathic surgery, but further investigations are required. © 2018 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Orthognathic Surgery; Piezoeletric; Saw; post-operative comfort
Introduction The aim of orthognathic surgery is to correct severe dentofacial deformities in adult patients whenever an orthodontic
∗ Corresponding author at: Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, IRCCS Istituto Ortopedico Galeazzi, Via Riccardo Galeazzi 4, 20161 Milano, Italy. Tel.: +39 02 50319950, Fax: +39 02 50319960. E-mail address: [email protected] (M. Del Fabbro).
approach alone is not enough.1 In addition to obviously compromised function, cosmesis is usually the main factor that motivates these patients to request surgical treatment. Modern orthognathic surgery, with advanced fixation systems and 3-dimensional programming, is capable of fulfilling both functional and aesthetic requirements, and most patients have reported long-term satisfaction with the outcome.2 However, the procedure remains uncomfortable, particularly during the postoperative recovery.3
https://doi.org/10.1016/j.bjoms.2018.07.011 0266-4356/© 2018 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
No. of Pages 7
2
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
It was not until the introduction of piezoelectric instruments that an alternative to the conventional saw technique for osteotomies was available. Piezoelectric surgery uses ultrasonic vibrations with low frequency (25–29 kHz) to cut mineralised tissues.4 It was first introduced by Vercellotti in 2004 as a new and safe procedure for sinus lifts,5 and it was soon exploited for other purposes including: extraction of impacted third molars;6 positioning of the inferior alveolar nerve;7 splitting of the alveolar ridge;8 placement of implants and removal of fractured implants; 9 enucleation of cysts;10 endodontic surgery;11 and periodontal surgery.12 Ultrasonic devices are thought to offer the advantages that they cut mineralised tissues selectively, and leave soft tissues or relevant structures such as nerves or blood vessels unharmed. Because of their cavitation effect and reduced bleeding, they offer better intraoperative visibility, and because of their low vibration amplitude, they are thought to cut more precisely and cause less trauma to the surrounding tissues.13 Because of these benefits, orthognathic surgeons started using the piezoelectric technique for osteotomies, with the main aim of reducing operative complications and postoperative discomfort.14 Several studies have compared the two techniques, and most concluded that piezoelectric surgery is superior to the conventional technique because of reduced bleeding and greater safety.15–18 However, few of the studies reported variables such as: swelling, postoperative pain, or sensitivity of the upper and lower lip.15 Consequently, the real impact of piezoelectric surgery is still not clear. The aim of this longitudinal case series study was to evaluate the effect of piezoelectric surgery compared with the conventional saw technique for osteotomies during orthognathic surgery on swelling of soft tissues, postoperative pain, and sensitivity of the upper and lower lips. We also recorded the overall operating time in both groups.
treated according to the principles of the Helsinki Declaration of 1980 for biomedical research involving human subjects, as revised in 2013. Surgical technique General anaesthesia was given by nasal intubation, and the same surgeon (who had more than 20 years’ experience in orthognathic surgery and was familiar with piezoelectric surgery) did all the bimaxillary orthognathic operations. The procedure included a LeFort I osteotomy for the maxilla and a bilateral sagittal split osteotomy (BSSO) for the mandible, with techniques previously reported elsewhere.19,20 Eleven patients had both maxillary and mandibular osteotomies using a conventional saw, while in 14 patients a piezoelec® tric device (PIEZOSURGERY , Mectron s.p.a Carasco (GE) was used. In the piezo group, all the osteotomies for LeFort I, and all the specific cuts for the BSSO (lingual, saggital, buccal, and lower mandibular border) were made using the piezoelectric saw. For all osteotomies we used the Piezo Tip Mectron MT1-10. Once all the mandibular cuts had been made with the piezoelectric tip, an osteotome was used to split the two fragments. All patients were given a total of hydrocortisone 24 mg of in three doses at precisely 30 minutes preoperatively (8 mg), the night of the operation (8 mg), and the first morning postoperatively (8 mg). All patients were also give acetaminophen 1 g and ketorolac 10 mg three times/day for two days postoperatively. On the third postoperative day the patient was given analgesics only if they were requested. This regimen was standardised for all patients. Outcomes
Materials and methods A total of 25 consecutive patients with dentofacial deformities (seven male and 18 female) were treated from January 2016 to September 2017 at the division of maxillofacial surgery of the Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico di Milano, Italy. Inclusion criteria were: adult patients with dentofacial deformities who needed bimaxillary orthodontic surgery without genioplasty and with no fragmentation of the maxilla. Exclusion criteria were: patients who needed segmented osteotomies or dentoalveolar osteotomies; skeletally immature patients or those with a history of maxillofacial trauma; suspected or confirmed pregnancy; patients with a reported problem with coagulation or patients with chronic diseases; and patients unable to give informed consent. The study was approved by the ethics committee of the Università degli Studi di Milano and written consent was given by all patients after they had been fully informed of the procedure and the essential follow-up plan. All patients were
The overall outcomes assessed included duration of operation and postoperative swelling. This was measured by ultrasonography (frequency 7.5 MHz) at nine selected anthropometric points: three midline and six bilateral (Fig. 1), with the patient sitting upright and with the head straight. Little gel and no pressure were used during the procedure and the thickness of soft tissues was measured.21 All ultrasound procedures were done by the same experienced operator. Postoperative pain was measured using a Visual Analogue Scale (VAS). It consists of a line that measures from 0 to 100 mm, the “0” indicating “no pain” and “100” indicating “the worst paint possible”. Patients were asked to sign the line at the point that they thought indicated the amount of pain that they were experiencing at that particular moment. Cutaneous sensitivity of the upper and lower lip were also measured, using a clinical neurosensory test (the Weber test), which is based on the discrimination of two different points.22,23 Four different areas were measured: the right and left sides of the upper lip, and of the lower lip. The test was done using open calipers, and the tips of the calipers consti-
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
No. of Pages 7
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
3
Fig. 1. Illustration of the nine anthropometric points used for measuring the postoperative swelling. Ls = on the midline between the base of the nose and philtrum of upper lip. Li = most priminent point of the chin on the midline. Me: the lowest point of the chin on the midline. Go = the angle of the mandible (dx = right side, sn = left side). Between Go and Me: +1dx and −1dx = 1 cm above and below lower border of mandible on the right, and +1 dx and −1dx = 1 cm above and below the lower border of the mandible on the left. Table 1 Scoring of neurosensory test for the sensitivity of the upper and lower lip. Difference between preoperative and postoperative values (mm)
Score
None 1–2 2–3 3–4 5–6 ≥6
5 4 3 2 1 0
tuted the two discrimination points. The test was done with the patient relaxed in a quiet room, and the skin was touched simultaneously with both tips of the calipers 2 mm away from each other. The test was repeated several times by increasing the distance between the two tips, and patients were asked to indicate the moment when they could distinguish the two separate points. That exact distance between the two tips of the calipers was measured, and a score was assigned based on the difference from the preoperative score (Table 1). Measurements for all three variables were repeated five times: before the operation (T0), the day after (T1), three days later (T2), seven days later (T3), and 30 days later (T4). Statistical analysis All data were analysed using GraphPad software (GraphPad Software Inc). Data are presented as mean (SD) for quantitative variables. The normality of the distributions was assessed by the D’Agostino and Pearson omnibus normality test. For pain, swelling, and sensitivity the Mann-Whitney test was used to assess the significance of differences between groups (piezosurgery compared with saw), and the Wilcoxon paired signed rank test for comparisons within groups (such as between different time frames). Student’s t test for inde-
pendent samples was used to compare the significance of the difference in operating times between groups. Probabilities of 0.05 or less were accepted as significant. Results Patients’ characteristics and duration of operation are shown in Table 2. The mean (SD) operating time for the conventional saw was 228.7 (29) minutes (95% CI 209.2 to 248.2), while for the piezoelectric saw it was 264.4 (23) minutes (95% CI 251.1 to 277.8). The difference was significant (p = 0.0023, t = 3.424, degrees of freedom = 23). Ultrasonography results showing soft tissue swelling are shown in Fig. 2. Those in the piezo group had less swelling at all follow-up visits compared with the saw group, and the difference was significant at the 30-day follow-up (p = 0.045). The areas more susceptible to swelling were the superior and the inferior lips, which differed significantly at 3, 7, and 30-days, with less swelling in the piezo group (Table 3). VAS scores for perception of pain are shown in Fig. 3. There was a significant difference only at the three-day follow up, with patients in the piezo group complaining of less pain (p = 0.035) (Table 3) A significant difference was found between the two groups in the results for the sensitivity test only at the 1-day follow up, and only for the right side of the upper lip (p = 0.04). No other difference was seen at any other time. Supplemental data, online only. Discussion For several years now, orthognathic surgery has accepted an alternative to the conventional saw technique for osteotomies
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464; 4
No. of Pages 7
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Fig. 2. Ultrasonography results of soft tissue swelling. Each graphic represents one of the nine points evaluated. Graphic no.10 shows the overall results of all nine points/patient. * indicates a significant difference. Headings: Ls = on the midline between the base of the nose and philtrum of upper lip. Li = most priminent point of the chin on the midline. Me: the lowest point of the chin on the midline. Go = the angle of the mandible (dx = right side, sn = left side). Between Go and Me: +1dx and −1dx = 1 cm above and below lower border of mandible on the right, and +1 dx and −1dx = 1 cm above and below the lower border of the mandible on the left.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
ARTICLE IN PRESS
No. of Pages 7
D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
5
Table 2 Details of patients, and type and duration of operation. Case No.
Age (years)
Sex
Class of skeletal abnormality
Technique
Duration (min)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
30 34 47 22 21 21 30 21 30 39 19 20 35 22 26 47 35 25 29 26 40 24 33 26 37
F M M F M F F F F F M F F F F F F M F F F F F M M
III III III II III III II II III III III II II II II III III III III II II III III III III
Saw Saw Piezo Saw Piezo Saw Saw Saw Saw Piezo Saw Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Saw Saw Saw
205 255 225 240 290 190 280 180 240 320 225 274 265 263 271 279 270 247 254 242 253 249 238 244 219
Table 3 P values shown by the Mann Whitney test for between-group comparisons of swelling of tissue at the various anthropometric points, and for the assessment of the visual analogue scale (VAS) for pain; 95% CI are also included for VAS. Points
Before operation
Day 1
Day 3
Day 7
Day 30
Ls Li Me Go.dx +1 Dx −1 Dx Go.sn +1 Sn −1 Sn Overall VAS 95% CI saw 95% CI piezo
0.43 0.07 0.55 0.51 0.16 0.06 0.93 0.11 0.07 0.11
0.89 0.64 0.44 0.78 0.49 0.23 0.25 1.00 0.96 0.87 0.99 0.00 to 1.05 0.41 to 0.59
0.02* 0.02* 0.09 0.74 0.58 0.23 0.05 0.66 0.15 0.32 0.035* 0.36 to 1.01 0.24 to 0.51
0.02* <0.001* 0.49 0.31 0.08 0.03* 0.31 0.46 0.12 0.08 0.65 −0.38 to 0.77 0.01 to 0.23
0.007* 0.004* 0.41 0.91 0.046* 0.22 0.64 0.046* 0.04* 0.05* 0.99 0.0 to 0.0 0.0 to 0.0
Ls = on the midline between the base of the nose and philtrum of upper lip. Li = most priminent point of the chin on the midline. Me: the lowest point of the chin on the midline. Go = the angle of the mandible (dx = right side, sn = left side). Between Go and Me: +1dx and −1dx = 1 cm above and below lower border of mandible on the right, and +1 dx and −1dx = 1 cm above and below the lower border of the mandible on the left. ∗ Indicates significant difference.
– piezoelectric surgery – which offers some valuable advantages that have been reported in previous studies. Nevertheless, there are also some disadvantages, mainly related to the duration of the osteotomy. The need to stop the cutting action every once in a while to permit the instrument to cool down prolongs the operating time, and some studies have reported a 30%–50% longer operating time when compared with a conventional bur. We found a significant difference (p = 0.0023) in operating time between the two groups, with the saw technique requiring less time for osteotomies. This
conclusion agrees with those of Spinelli et al15 and Rana et al17 but not with the systematic review by Pagotto et al18 who reported no difference. It is questionable, therefore, whether piezoelectric surgery can be a substitute for the conventional saw in orthognathic surgery, or just an alternative under specific circumstances. To answer this, investigators have focused on comparing the effect of those two techniques on variables related to patients’ postoperative discomfort, such as swelling, pain, and the sensitivity of the inferior alveolar nerve.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464; 6
No. of Pages 7
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Fig. 3. Comparison of mean (SD) visual analogue scores for perception of pain between piezoelectric surgery and saw technique at different follow-up times. There was a significant difference at T2 (p = 0.035).
To evaluate swelling, Spinelli at al15 used a method based on photographs taken of the patient before and after the operation. We used a different method, based on the description of Shetty at al21 which evaluates the swelling ultrasonographically. We concluded that patients in the piezo group had less swelling (as judged at all follow-up visits) than the conventional group, and this difference was significant at the 30-day follow-up (Fig .2, graph 10). This is in agreement with most of the conclusions of Spinelli et al. However, contrary to these, we found a persistence of swelling at the 30-day follow-up in both groups. We also found that the different points evaluated illustrated a different level of swelling, with the upper and lower lips being the most sensitive points, where there were significant differences between the two groups at the three, seven, and 30-day follow-up visits (Fig. 2, graphs 1–9). As far as the perception of pain was concerned, we found a significant difference between the two groups only at the 3-day follow up, with patients of the piezo group saying that they had less pain (Fig. 3). Based on these results, we think that piezoelectric surgery is better for patients during the acute phase of recovery, whereas on the following days the perception pain of is similar in both groups. However, Rana et al17 found no difference in the perception of pain between the two groups when doing a surgically-assisted rapid palatal expansion. Finally, the reported results of testing the sensitivity of the upper and lower lip are controversial. Spinelli et al15 concluded that there was a significant difference at the 30day follow-up visit, with less impairment of sensitivity in the piezo group. However, in a systematic review and metaanalyses of five studies, Pagotto et al18 showed a significant difference between the two groups only at the three-month and six-month follow-up visits. We found a significant difference between the two groups only at the right side of the upper lip at the one-day follow up, and no other differences in
sensitivity of the upper and lower lip between the two groups at any follow-up time (Table 3). A recent systematic review24 concluded that the type of instrument used for the final splitting may influence the possibility of postoperative hypoaesthesia, with spreaders offering better results than chisels. The osteotome that we used may therefore have had some influence in the results of postoperative sensitivity. However, our osteotome was used only for its leverage effect to split the two segments, and we did not move its tip along the buccal or lingual cortex. In addition, the same osteotome was used for both groups (piezo and saw), which minimises its influence on the outcome unless there is a specific correlation between the combination of piezoeletric cutting and splitting with an osteotome. To our knowledge, such correlation has never been confirmed, but might be the subject of future investigations. Overall, piezoelectric surgery requires a longer operating time, swelling was more rapidly resorbed, and pain was significantly less in patients who had had it. However, the sensitivity of the upper and lower lip was not influenced by the surgical technique.
Conclusions Within the limitations of this study, we conclude that piezoelectric surgery offers some advantages in terms of perception of pain and swelling after orthognathic surgery. Further investigations with more patients need to be undertaken to come to more reliable conclusions.
Conflict of interest We have no conflicts of interest.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
ARTICLE IN PRESS
No. of Pages 7
D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Ethics statement/confirmation of patients’ permission The study was approved by the ethics committee of the Università degli Studi di Milano. All patients gave their written consent. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at https://doi.org/10.1016/j.bjoms. 2018.07.011. References 1. Posnick JC. Craniofacial and maxillofacial surgery in children and young adults (Vols 1 and 2). WB Saunders; 2000. 2. Proffitt WR, White Jr RP, Sarver DM. Contemporary treatment of dentofacial deformity. 1st ed Mosby International; 2002. 3. Jedrzejewski M, Smektala T, Sporniak-Tutak K, et al. Preoperative, intraoperative, and postoperative complications in orthognathic surgery: a systematic review. Clin Oral Investig 2015;19:969–77. 4. Vercellotti T. Technological characteristics and clinical indications of piezoelectric bone surgery. Minerva Stomatol 2004;53:207–14. 5. Vercellotti T, De Paoli S, Nevins M. The piezoelectric bony window osteotomy and sinus membrane elevation: introduction of a new technique for simplification of the sinus augmentation procedure. Int J Periodontic Restorative Dent 2001;21:561–7. 6. Sortino F, Pedullà E, Masoli V. The piezoelectric and rotatory osteotomy technique in impacted third molar surgery: comparison of postoperative recovery. J Oral Maxillofac Surg 2008;66:2444–8. 7. Nusrath MA, Postlethwaite KR. Use of piezosurgery in calvarial bone grafts and for release of the inferior alveolar nerve in sagittal split osteotomy: technical note. Br J Oral Maxillofac Surg 2011;49: 668–9. 8. Blus C, Szmukler-Moncler S, Vozza I, et al. Split-crest and immediate implant placement with ultrasonic bone surgery (piezosurgery): 3-year follow-up of 180 treated implant sites. Quintessence Int 2010;41:463–9. 9. Canullo L, Pe˜nrrocha C, Pe˜nrrocha M, et al. Piezoelectric vs: conventional drilling in implant site preparation: pilot controlled randomized clinical trial with crossover design. Clin Oral Implants Res 2014;25:1336–43.
7
10. Pappalardo S, Guarnieri R. Randomized clinical study comparing piezosurgery and conventional rotatory surgery in mandibular cyst enucleation. J Craniomaxillofac Surg 2014;42:e80–5. 11. Tortorici S, Difalco P, Caradonna L, et al. Traditional endodontic surgery versus modern technique: a 5-year controlled clinical trial. J Craniofac Surg 2014;25:804–7. 12. Seshan H, Konuganti K, Zope S. Piezosurgery in periodontology and oral implantology. J Indian Soc Periodontol 2009;13:155–6. 13. Pereira CC, Gealh WC, Meorin-Nogueira L, et al. Piezosurgery applied to implant dentistry: clinical and biological aspects. J Oral Implantol 2014;40:401–8. 14. Gonzàlez-Garcia A, Diniz-Freitas M, Somoza-Martin M, et al. Ultrasonic osteotomy in oral surgery and implantology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108:306–7. 15. Spinelli G, Lazzeri D, Conti M, et al. Comparison of piezosurgery and traditional saw in bimaxillary orthognathic surgery. J Craniomaxillofac Surg 2014;42:1211–20. 16. Bertossi D, Lucchese A, Albanese M, et al. Piezosurgery versus conventional osteotomy in orthognathic surgery: a paradigm shift in treatment. J Craniofac Surg 2013;24:1763–6. 17. Rana M, Gellrich N, Rana M, et al. Evaluation of surgically assisted rapid maxillary expansion with piezosurgery versus oscillating saw and chisel osteotomy − a randomized prospective trial. Trials 2013;14:49. 18. Pagotto LE, Santos T, Vasconcellos SJ, et al. Piezoelectric versus conventional techniques for orthognathic surgery: systematic review and meta-analysis. J Craniomaxillofac Surg 2017;45:1607–13. 19. Islam S, Uwadiae N, Orniston IW. Orthognathic surgery in the management of obstructive sleep apnoea: experience from maxillofacial surgery unit in the United Kingdom. Br J Oral Maxillofac Surg 2014;52:496–500. 20. Schwartz HC. Efficient surgical management of mandibular asymmetry. J Oral Maxillofac Surg 2011;69:645–54. 21. Shetty V, Mohan A. A prospective, randomized, double-blind, placebocontrolled clinical trial comparing the efficacy of systemic enzyme therapy for edema control in orthognathic surgery using ultrasound scan to measure facial swelling. J Oral Maxillofac Surg 2013;71:1261–7. 22. Gianni AB, D’Orto O, Biglioli F, et al. Neurosensory alterations of the inferior alveolar and mental nerve after genioplasty alone or associated with sagittal osteotomy of the mandibular ramus. J Craniomaxillofac Surg 2002;30:295–303. 23. Geha HJ, Gleizal AM, Nimeskern NJ, et al. Sensitivity of the inferior lip and chin following mandibular bilateral sagittal split osteotomy using Piezosurgery. Plast Reconstr Surg 2006;118:1598–607. 24. Mensink G, Gooris PJ, Bergsma JE, et al. Influence of BSSO surgical technique on postoperative inferior alveolar nerve hypoesthesia: a systematic review of the literature. J Craniomaxillofac Surg 2014;42:976–82.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
No. of Pages 7
ARTICLE IN PRESS Available online at www.sciencedirect.com
ScienceDirect British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study D. Rossi a , M. Romano a , L. Karanxha b , C. Baserga c , A. Russillo c , S. Taschieri b,e , M. Del Fabbro b,d,∗ , A.B. Giannì c , A. Baj a a
Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Maxillo-Facial and Dental Unit, Fondazione Ca’ Granda IRCCS Ospedale Maggiore Policlinico Milan, Italy b Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, Milan, Italy c Università degli Studi di Milano, Maxillo-Facial and Dental Unit, Fondazione Ca’ Granda IRCCS Ospedale Maggiore Policlinico Milan, Italy d Dental Clinic, IRCCS Istituto Ortopedico Galeazzi, Milan, Italy e Faculty of Dental Surgery, I.M Sechenov First Moscow State Medical University Accepted 12 July 2018
Abstract The only cutting technique used for osteotomies in orthognathic surgery for many years has been a saw, but recently piezoelectric surgery has been introduced as a possible alternative. The aim of this study was to find out if piezoelectric surgery can be more comfortable for patients having orthognathic surgery. A total of 25 patients with dentofacial deformities (seven male and 18 female), were treated from January 2016 to September 2017. In 11 patients, osteotomies were made using a conventional saw, while in 14 a piezoelectric device was used. The variables assessed were: operating time, postoperative swelling, postoperative pain, and cutaneous sensitivity of the upper and lower lips. The duration of operation for the piezosurgery group was significantly longer than that for controls, but the patients had less swelling at all follow-up visits, and the difference was significant at the 30-day follow-up (p = 0.045). Those who had piezosurgery had significantly less pain at the three-day follow up (p = 0.035). There was a significant difference in cutaneous sensitivity only for the right side of the upper lip and only at the one-day follow-up. We conclude that piezoelectric surgery offers some advantages in lessening swelling and the perception of pain after orthognathic surgery, but further investigations are required. © 2018 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved. Keywords: Orthognathic Surgery; Piezoeletric; Saw; post-operative comfort
Introduction The aim of orthognathic surgery is to correct severe dentofacial deformities in adult patients whenever an orthodontic
∗ Corresponding author at: Department of Biomedical, Surgical and Dental Sciences, Università degli Studi di Milano, IRCCS Istituto Ortopedico Galeazzi, Via Riccardo Galeazzi 4, 20161 Milano, Italy. Tel.: +39 02 50319950, Fax: +39 02 50319960. E-mail address: [email protected] (M. Del Fabbro).
approach alone is not enough.1 In addition to obviously compromised function, cosmesis is usually the main factor that motivates these patients to request surgical treatment. Modern orthognathic surgery, with advanced fixation systems and 3-dimensional programming, is capable of fulfilling both functional and aesthetic requirements, and most patients have reported long-term satisfaction with the outcome.2 However, the procedure remains uncomfortable, particularly during the postoperative recovery.3
https://doi.org/10.1016/j.bjoms.2018.07.011 0266-4356/© 2018 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
No. of Pages 7
2
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
It was not until the introduction of piezoelectric instruments that an alternative to the conventional saw technique for osteotomies was available. Piezoelectric surgery uses ultrasonic vibrations with low frequency (25–29 kHz) to cut mineralised tissues.4 It was first introduced by Vercellotti in 2004 as a new and safe procedure for sinus lifts,5 and it was soon exploited for other purposes including: extraction of impacted third molars;6 positioning of the inferior alveolar nerve;7 splitting of the alveolar ridge;8 placement of implants and removal of fractured implants; 9 enucleation of cysts;10 endodontic surgery;11 and periodontal surgery.12 Ultrasonic devices are thought to offer the advantages that they cut mineralised tissues selectively, and leave soft tissues or relevant structures such as nerves or blood vessels unharmed. Because of their cavitation effect and reduced bleeding, they offer better intraoperative visibility, and because of their low vibration amplitude, they are thought to cut more precisely and cause less trauma to the surrounding tissues.13 Because of these benefits, orthognathic surgeons started using the piezoelectric technique for osteotomies, with the main aim of reducing operative complications and postoperative discomfort.14 Several studies have compared the two techniques, and most concluded that piezoelectric surgery is superior to the conventional technique because of reduced bleeding and greater safety.15–18 However, few of the studies reported variables such as: swelling, postoperative pain, or sensitivity of the upper and lower lip.15 Consequently, the real impact of piezoelectric surgery is still not clear. The aim of this longitudinal case series study was to evaluate the effect of piezoelectric surgery compared with the conventional saw technique for osteotomies during orthognathic surgery on swelling of soft tissues, postoperative pain, and sensitivity of the upper and lower lips. We also recorded the overall operating time in both groups.
treated according to the principles of the Helsinki Declaration of 1980 for biomedical research involving human subjects, as revised in 2013. Surgical technique General anaesthesia was given by nasal intubation, and the same surgeon (who had more than 20 years’ experience in orthognathic surgery and was familiar with piezoelectric surgery) did all the bimaxillary orthognathic operations. The procedure included a LeFort I osteotomy for the maxilla and a bilateral sagittal split osteotomy (BSSO) for the mandible, with techniques previously reported elsewhere.19,20 Eleven patients had both maxillary and mandibular osteotomies using a conventional saw, while in 14 patients a piezoelec® tric device (PIEZOSURGERY , Mectron s.p.a Carasco (GE) was used. In the piezo group, all the osteotomies for LeFort I, and all the specific cuts for the BSSO (lingual, saggital, buccal, and lower mandibular border) were made using the piezoelectric saw. For all osteotomies we used the Piezo Tip Mectron MT1-10. Once all the mandibular cuts had been made with the piezoelectric tip, an osteotome was used to split the two fragments. All patients were given a total of hydrocortisone 24 mg of in three doses at precisely 30 minutes preoperatively (8 mg), the night of the operation (8 mg), and the first morning postoperatively (8 mg). All patients were also give acetaminophen 1 g and ketorolac 10 mg three times/day for two days postoperatively. On the third postoperative day the patient was given analgesics only if they were requested. This regimen was standardised for all patients. Outcomes
Materials and methods A total of 25 consecutive patients with dentofacial deformities (seven male and 18 female) were treated from January 2016 to September 2017 at the division of maxillofacial surgery of the Fondazione IRCCS Cà Granda, Ospedale Maggiore Policlinico di Milano, Italy. Inclusion criteria were: adult patients with dentofacial deformities who needed bimaxillary orthodontic surgery without genioplasty and with no fragmentation of the maxilla. Exclusion criteria were: patients who needed segmented osteotomies or dentoalveolar osteotomies; skeletally immature patients or those with a history of maxillofacial trauma; suspected or confirmed pregnancy; patients with a reported problem with coagulation or patients with chronic diseases; and patients unable to give informed consent. The study was approved by the ethics committee of the Università degli Studi di Milano and written consent was given by all patients after they had been fully informed of the procedure and the essential follow-up plan. All patients were
The overall outcomes assessed included duration of operation and postoperative swelling. This was measured by ultrasonography (frequency 7.5 MHz) at nine selected anthropometric points: three midline and six bilateral (Fig. 1), with the patient sitting upright and with the head straight. Little gel and no pressure were used during the procedure and the thickness of soft tissues was measured.21 All ultrasound procedures were done by the same experienced operator. Postoperative pain was measured using a Visual Analogue Scale (VAS). It consists of a line that measures from 0 to 100 mm, the “0” indicating “no pain” and “100” indicating “the worst paint possible”. Patients were asked to sign the line at the point that they thought indicated the amount of pain that they were experiencing at that particular moment. Cutaneous sensitivity of the upper and lower lip were also measured, using a clinical neurosensory test (the Weber test), which is based on the discrimination of two different points.22,23 Four different areas were measured: the right and left sides of the upper lip, and of the lower lip. The test was done using open calipers, and the tips of the calipers consti-
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
No. of Pages 7
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
3
Fig. 1. Illustration of the nine anthropometric points used for measuring the postoperative swelling. Ls = on the midline between the base of the nose and philtrum of upper lip. Li = most priminent point of the chin on the midline. Me: the lowest point of the chin on the midline. Go = the angle of the mandible (dx = right side, sn = left side). Between Go and Me: +1dx and −1dx = 1 cm above and below lower border of mandible on the right, and +1 dx and −1dx = 1 cm above and below the lower border of the mandible on the left. Table 1 Scoring of neurosensory test for the sensitivity of the upper and lower lip. Difference between preoperative and postoperative values (mm)
Score
None 1–2 2–3 3–4 5–6 ≥6
5 4 3 2 1 0
tuted the two discrimination points. The test was done with the patient relaxed in a quiet room, and the skin was touched simultaneously with both tips of the calipers 2 mm away from each other. The test was repeated several times by increasing the distance between the two tips, and patients were asked to indicate the moment when they could distinguish the two separate points. That exact distance between the two tips of the calipers was measured, and a score was assigned based on the difference from the preoperative score (Table 1). Measurements for all three variables were repeated five times: before the operation (T0), the day after (T1), three days later (T2), seven days later (T3), and 30 days later (T4). Statistical analysis All data were analysed using GraphPad software (GraphPad Software Inc). Data are presented as mean (SD) for quantitative variables. The normality of the distributions was assessed by the D’Agostino and Pearson omnibus normality test. For pain, swelling, and sensitivity the Mann-Whitney test was used to assess the significance of differences between groups (piezosurgery compared with saw), and the Wilcoxon paired signed rank test for comparisons within groups (such as between different time frames). Student’s t test for inde-
pendent samples was used to compare the significance of the difference in operating times between groups. Probabilities of 0.05 or less were accepted as significant. Results Patients’ characteristics and duration of operation are shown in Table 2. The mean (SD) operating time for the conventional saw was 228.7 (29) minutes (95% CI 209.2 to 248.2), while for the piezoelectric saw it was 264.4 (23) minutes (95% CI 251.1 to 277.8). The difference was significant (p = 0.0023, t = 3.424, degrees of freedom = 23). Ultrasonography results showing soft tissue swelling are shown in Fig. 2. Those in the piezo group had less swelling at all follow-up visits compared with the saw group, and the difference was significant at the 30-day follow-up (p = 0.045). The areas more susceptible to swelling were the superior and the inferior lips, which differed significantly at 3, 7, and 30-days, with less swelling in the piezo group (Table 3). VAS scores for perception of pain are shown in Fig. 3. There was a significant difference only at the three-day follow up, with patients in the piezo group complaining of less pain (p = 0.035) (Table 3) A significant difference was found between the two groups in the results for the sensitivity test only at the 1-day follow up, and only for the right side of the upper lip (p = 0.04). No other difference was seen at any other time. Supplemental data, online only. Discussion For several years now, orthognathic surgery has accepted an alternative to the conventional saw technique for osteotomies
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464; 4
No. of Pages 7
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Fig. 2. Ultrasonography results of soft tissue swelling. Each graphic represents one of the nine points evaluated. Graphic no.10 shows the overall results of all nine points/patient. * indicates a significant difference. Headings: Ls = on the midline between the base of the nose and philtrum of upper lip. Li = most priminent point of the chin on the midline. Me: the lowest point of the chin on the midline. Go = the angle of the mandible (dx = right side, sn = left side). Between Go and Me: +1dx and −1dx = 1 cm above and below lower border of mandible on the right, and +1 dx and −1dx = 1 cm above and below the lower border of the mandible on the left.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
ARTICLE IN PRESS
No. of Pages 7
D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
5
Table 2 Details of patients, and type and duration of operation. Case No.
Age (years)
Sex
Class of skeletal abnormality
Technique
Duration (min)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
30 34 47 22 21 21 30 21 30 39 19 20 35 22 26 47 35 25 29 26 40 24 33 26 37
F M M F M F F F F F M F F F F F F M F F F F F M M
III III III II III III II II III III III II II II II III III III III II II III III III III
Saw Saw Piezo Saw Piezo Saw Saw Saw Saw Piezo Saw Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Piezo Saw Saw Saw
205 255 225 240 290 190 280 180 240 320 225 274 265 263 271 279 270 247 254 242 253 249 238 244 219
Table 3 P values shown by the Mann Whitney test for between-group comparisons of swelling of tissue at the various anthropometric points, and for the assessment of the visual analogue scale (VAS) for pain; 95% CI are also included for VAS. Points
Before operation
Day 1
Day 3
Day 7
Day 30
Ls Li Me Go.dx +1 Dx −1 Dx Go.sn +1 Sn −1 Sn Overall VAS 95% CI saw 95% CI piezo
0.43 0.07 0.55 0.51 0.16 0.06 0.93 0.11 0.07 0.11
0.89 0.64 0.44 0.78 0.49 0.23 0.25 1.00 0.96 0.87 0.99 0.00 to 1.05 0.41 to 0.59
0.02* 0.02* 0.09 0.74 0.58 0.23 0.05 0.66 0.15 0.32 0.035* 0.36 to 1.01 0.24 to 0.51
0.02* <0.001* 0.49 0.31 0.08 0.03* 0.31 0.46 0.12 0.08 0.65 −0.38 to 0.77 0.01 to 0.23
0.007* 0.004* 0.41 0.91 0.046* 0.22 0.64 0.046* 0.04* 0.05* 0.99 0.0 to 0.0 0.0 to 0.0
Ls = on the midline between the base of the nose and philtrum of upper lip. Li = most priminent point of the chin on the midline. Me: the lowest point of the chin on the midline. Go = the angle of the mandible (dx = right side, sn = left side). Between Go and Me: +1dx and −1dx = 1 cm above and below lower border of mandible on the right, and +1 dx and −1dx = 1 cm above and below the lower border of the mandible on the left. ∗ Indicates significant difference.
– piezoelectric surgery – which offers some valuable advantages that have been reported in previous studies. Nevertheless, there are also some disadvantages, mainly related to the duration of the osteotomy. The need to stop the cutting action every once in a while to permit the instrument to cool down prolongs the operating time, and some studies have reported a 30%–50% longer operating time when compared with a conventional bur. We found a significant difference (p = 0.0023) in operating time between the two groups, with the saw technique requiring less time for osteotomies. This
conclusion agrees with those of Spinelli et al15 and Rana et al17 but not with the systematic review by Pagotto et al18 who reported no difference. It is questionable, therefore, whether piezoelectric surgery can be a substitute for the conventional saw in orthognathic surgery, or just an alternative under specific circumstances. To answer this, investigators have focused on comparing the effect of those two techniques on variables related to patients’ postoperative discomfort, such as swelling, pain, and the sensitivity of the inferior alveolar nerve.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464; 6
No. of Pages 7
ARTICLE IN PRESS D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Fig. 3. Comparison of mean (SD) visual analogue scores for perception of pain between piezoelectric surgery and saw technique at different follow-up times. There was a significant difference at T2 (p = 0.035).
To evaluate swelling, Spinelli at al15 used a method based on photographs taken of the patient before and after the operation. We used a different method, based on the description of Shetty at al21 which evaluates the swelling ultrasonographically. We concluded that patients in the piezo group had less swelling (as judged at all follow-up visits) than the conventional group, and this difference was significant at the 30-day follow-up (Fig .2, graph 10). This is in agreement with most of the conclusions of Spinelli et al. However, contrary to these, we found a persistence of swelling at the 30-day follow-up in both groups. We also found that the different points evaluated illustrated a different level of swelling, with the upper and lower lips being the most sensitive points, where there were significant differences between the two groups at the three, seven, and 30-day follow-up visits (Fig. 2, graphs 1–9). As far as the perception of pain was concerned, we found a significant difference between the two groups only at the 3-day follow up, with patients of the piezo group saying that they had less pain (Fig. 3). Based on these results, we think that piezoelectric surgery is better for patients during the acute phase of recovery, whereas on the following days the perception pain of is similar in both groups. However, Rana et al17 found no difference in the perception of pain between the two groups when doing a surgically-assisted rapid palatal expansion. Finally, the reported results of testing the sensitivity of the upper and lower lip are controversial. Spinelli et al15 concluded that there was a significant difference at the 30day follow-up visit, with less impairment of sensitivity in the piezo group. However, in a systematic review and metaanalyses of five studies, Pagotto et al18 showed a significant difference between the two groups only at the three-month and six-month follow-up visits. We found a significant difference between the two groups only at the right side of the upper lip at the one-day follow up, and no other differences in
sensitivity of the upper and lower lip between the two groups at any follow-up time (Table 3). A recent systematic review24 concluded that the type of instrument used for the final splitting may influence the possibility of postoperative hypoaesthesia, with spreaders offering better results than chisels. The osteotome that we used may therefore have had some influence in the results of postoperative sensitivity. However, our osteotome was used only for its leverage effect to split the two segments, and we did not move its tip along the buccal or lingual cortex. In addition, the same osteotome was used for both groups (piezo and saw), which minimises its influence on the outcome unless there is a specific correlation between the combination of piezoeletric cutting and splitting with an osteotome. To our knowledge, such correlation has never been confirmed, but might be the subject of future investigations. Overall, piezoelectric surgery requires a longer operating time, swelling was more rapidly resorbed, and pain was significantly less in patients who had had it. However, the sensitivity of the upper and lower lip was not influenced by the surgical technique.
Conclusions Within the limitations of this study, we conclude that piezoelectric surgery offers some advantages in terms of perception of pain and swelling after orthognathic surgery. Further investigations with more patients need to be undertaken to come to more reliable conclusions.
Conflict of interest We have no conflicts of interest.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011
YBJOM-5464;
ARTICLE IN PRESS
No. of Pages 7
D. Rossi et al. / British Journal of Oral and Maxillofacial Surgery xxx (2017) xxx–xxx
Ethics statement/confirmation of patients’ permission The study was approved by the ethics committee of the Università degli Studi di Milano. All patients gave their written consent. Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at https://doi.org/10.1016/j.bjoms. 2018.07.011. References 1. Posnick JC. Craniofacial and maxillofacial surgery in children and young adults (Vols 1 and 2). WB Saunders; 2000. 2. Proffitt WR, White Jr RP, Sarver DM. Contemporary treatment of dentofacial deformity. 1st ed Mosby International; 2002. 3. Jedrzejewski M, Smektala T, Sporniak-Tutak K, et al. Preoperative, intraoperative, and postoperative complications in orthognathic surgery: a systematic review. Clin Oral Investig 2015;19:969–77. 4. Vercellotti T. Technological characteristics and clinical indications of piezoelectric bone surgery. Minerva Stomatol 2004;53:207–14. 5. Vercellotti T, De Paoli S, Nevins M. The piezoelectric bony window osteotomy and sinus membrane elevation: introduction of a new technique for simplification of the sinus augmentation procedure. Int J Periodontic Restorative Dent 2001;21:561–7. 6. Sortino F, Pedullà E, Masoli V. The piezoelectric and rotatory osteotomy technique in impacted third molar surgery: comparison of postoperative recovery. J Oral Maxillofac Surg 2008;66:2444–8. 7. Nusrath MA, Postlethwaite KR. Use of piezosurgery in calvarial bone grafts and for release of the inferior alveolar nerve in sagittal split osteotomy: technical note. Br J Oral Maxillofac Surg 2011;49: 668–9. 8. Blus C, Szmukler-Moncler S, Vozza I, et al. Split-crest and immediate implant placement with ultrasonic bone surgery (piezosurgery): 3-year follow-up of 180 treated implant sites. Quintessence Int 2010;41:463–9. 9. Canullo L, Pe˜nrrocha C, Pe˜nrrocha M, et al. Piezoelectric vs: conventional drilling in implant site preparation: pilot controlled randomized clinical trial with crossover design. Clin Oral Implants Res 2014;25:1336–43.
7
10. Pappalardo S, Guarnieri R. Randomized clinical study comparing piezosurgery and conventional rotatory surgery in mandibular cyst enucleation. J Craniomaxillofac Surg 2014;42:e80–5. 11. Tortorici S, Difalco P, Caradonna L, et al. Traditional endodontic surgery versus modern technique: a 5-year controlled clinical trial. J Craniofac Surg 2014;25:804–7. 12. Seshan H, Konuganti K, Zope S. Piezosurgery in periodontology and oral implantology. J Indian Soc Periodontol 2009;13:155–6. 13. Pereira CC, Gealh WC, Meorin-Nogueira L, et al. Piezosurgery applied to implant dentistry: clinical and biological aspects. J Oral Implantol 2014;40:401–8. 14. Gonzàlez-Garcia A, Diniz-Freitas M, Somoza-Martin M, et al. Ultrasonic osteotomy in oral surgery and implantology. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108:306–7. 15. Spinelli G, Lazzeri D, Conti M, et al. Comparison of piezosurgery and traditional saw in bimaxillary orthognathic surgery. J Craniomaxillofac Surg 2014;42:1211–20. 16. Bertossi D, Lucchese A, Albanese M, et al. Piezosurgery versus conventional osteotomy in orthognathic surgery: a paradigm shift in treatment. J Craniofac Surg 2013;24:1763–6. 17. Rana M, Gellrich N, Rana M, et al. Evaluation of surgically assisted rapid maxillary expansion with piezosurgery versus oscillating saw and chisel osteotomy − a randomized prospective trial. Trials 2013;14:49. 18. Pagotto LE, Santos T, Vasconcellos SJ, et al. Piezoelectric versus conventional techniques for orthognathic surgery: systematic review and meta-analysis. J Craniomaxillofac Surg 2017;45:1607–13. 19. Islam S, Uwadiae N, Orniston IW. Orthognathic surgery in the management of obstructive sleep apnoea: experience from maxillofacial surgery unit in the United Kingdom. Br J Oral Maxillofac Surg 2014;52:496–500. 20. Schwartz HC. Efficient surgical management of mandibular asymmetry. J Oral Maxillofac Surg 2011;69:645–54. 21. Shetty V, Mohan A. A prospective, randomized, double-blind, placebocontrolled clinical trial comparing the efficacy of systemic enzyme therapy for edema control in orthognathic surgery using ultrasound scan to measure facial swelling. J Oral Maxillofac Surg 2013;71:1261–7. 22. Gianni AB, D’Orto O, Biglioli F, et al. Neurosensory alterations of the inferior alveolar and mental nerve after genioplasty alone or associated with sagittal osteotomy of the mandibular ramus. J Craniomaxillofac Surg 2002;30:295–303. 23. Geha HJ, Gleizal AM, Nimeskern NJ, et al. Sensitivity of the inferior lip and chin following mandibular bilateral sagittal split osteotomy using Piezosurgery. Plast Reconstr Surg 2006;118:1598–607. 24. Mensink G, Gooris PJ, Bergsma JE, et al. Influence of BSSO surgical technique on postoperative inferior alveolar nerve hypoesthesia: a systematic review of the literature. J Craniomaxillofac Surg 2014;42:976–82.
Please cite this article in press as: Rossi D, et al. Bimaxillary orthognathic surgery with a conventional saw compared with the piezoelectric technique: a longitudinal clinical study. Br J Oral Maxillofac Surg (2017), https://doi.org/10.1016/j.bjoms.2018.07.011