- Email: [email protected]
Transoral Fixation of Bicortical Screws Is Safe and Feasible for Lower Jaw Osteotomies
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CRANIOMAXILLOFACIAL DEFORMITIES/COSMETIC SURGERY
Transoral Fixation of Bicortical Screws Is Safe and Feasible for Lower Jaw Osteotomies Bart Jozef Falter, MD, DDS,* Johan Abeloos, MD, DDS, PhD,y Calix De Clercq, MD, DDS, PhD,z Nathalie Neyt, MD, DDS,x Philippe Lamoral, MD, DDS,k and Gwen R. Swennen, MD, DDS, PhD{
Q8
Q2
Purpose:
Transoral placement of bicortical screws is a rigid fixation method in orthognathic surgery that is used less often than transbuccal placement. The aim of this study was to examine the postoperative outcome of transoral bicortical screw insertion during orthognathic surgery and to compare it with the more common transbuccal fixation technique.
Materials and Methods:
A retrospective cohort study was conducted. Clinical files of orthognathic surgical patients operated on from January 2010 through December 2012 were reviewed. Screw insertion approach (transoral vs transbuccal) was examined as a predictive variable for postoperative complications (hardware removal and infection). Type of surgery, fibrin sealant, preoperative third molar removal, and patient age and gender were analyzed as potential risk factors. Descriptive and bivariate statistics and regression analyses were performed. Of the 606 patients whose cases were reviewed, 509 patients (185 men; mean age, 26.3 11.1 yr) met the inclusion criteria. Most presented with a Class II malocclusion (84.5%). A transbuccal approach was used in 27.5% of cases, leading to a screw-related infection of 6.3%. Patients treated with a transoral technique (72.5%) had fewer infections (3.5%), but this was not statistically relevant. Screw removal was indicated in 3.3% of patients. Screw placement using the transoral and transbuccal approaches was performed in 3.0 and 4.2% of patients, respectively. Infection and screw removal rates did not differ significantly between fixation techniques (P = .16 and P = .49, respectively).
Results:
Conclusion: Q3
The present findings showed an overall low rate of screw removal and infection secondary to bicortical screw insertion during orthognathic surgery. The postoperative outcome was similar for the transoral and transbuccal approaches. Ó 2016 Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg -:1.e1-1.e8, 2016 Bicortical screws have been widely used for mandibular osteosynthesis during orthognathic surgery. Lindorf1 was the first to adapt rigid fixation with lag screws as described by Spiessl2 by placing positioning screws without compression. In this way, he prevented entrapment of the inferior alveolar nerve
(IAN). In most units, it is routine policy to retain the osteosynthesis screws after bony union unless removal is clinically indicated. Currently, the reported incidence of screw removal per patient in orthognathic surgery ranges from 2.8 to 14.5% in mandibular osteotomies secondary to a transbuccal approach.3-6
Received from Division of Maxillofacial Surgery, Department of
Bruges-Ostend av, Ruddershove 10, Bruges 8000, Belgium; e-mail:
Surgery, GH St John, Bruges-Ostend, Belgium.
[email protected]
*Resident.
Received February 8 2016
yDepartment Head. zStaff Member.
Ó 2016 Published by Elsevier Inc on behalf of the American Association of Oral
xStaff Member.
and Maxillofacial Surgeons
kStaff Member.
0278-2391/16/30609-7
Accepted July 3 2016
{Professor.
http://dx.doi.org/10.1016/j.joms.2016.07.006
Address correspondence and reprint requests to Dr Falter: Division of Maxillofacial Surgery, Department of Surgery, GH St John,
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TRANSORAL FIXATION FOR OSTEOTOMIES
Many studies have investigated the complications and fixation stability of bicortical screws placed with a transbuccal technique, which provides safe osteosynthesis in orthognathic surgery.4-6 Reported complications of the transbuccal approach include early loosening of screws, palpable screws, skeletal instability related or unrelated to a pseudoarthrosis, infection, and scar formation.4 However, although technically more demanding, the transoral approach also has been frequently applied in the authors’ center to avoid extraoral scars. Despite the obvious advantage of the redundancy of a skin incision for screw insertion in the transoral approach, there are no studies describing the transoral technique for orthognathic surgery. Moreover, no studies could be found that compared the transbuccal with the transoral approach in orthognathic surgery for postsurgical morbidity. The purpose of this retrospective study was to examine and compare screw removal and infection rate, as postoperative complications, after transoral vs transbuccal bicortical screw fixation during orthognathic surgery. The authors hypothesized a higher risk for complications in the transbuccal approach owing to the temporary extraoral communication. Moreover, the authors aimed to define risk factors indicative for these screw-related postoperative complications.
Materials and Methods STUDY DESIGN
The authors performed a retrospective cohort study. STUDY SAMPLE
The records of all consecutive patients who presented at the Division of Maxillofacial Surgery of AZ Sint-Jan Brugge-Oostende av (Bruges, Belgium) for orthognathic surgery from January 2010 through December 2012 were reviewed retrospectively. To be included in the study sample, patients had to undergo a bimaxillary osteotomy, a bilateral sagittal split ramus osteotomy (BSSO), a BSSO with a genioplasty, or a bimaxillary osteotomy with genioplasty performed by 1 of the 7 senior staff members of the division. Patients were excluded as study subjects if bone cement Norian (Synthes, Bettlach, Switzerland) or Hydroset (Stryker, Kalamazoo, MI) had been used at the osteotomy sites. Other exclusion criteria included a multisegment mandibular osteotomy, osteosynthesis with plates, no postoperative orthopantomogram available, and no data on the type of placement of the screws. OPERATIVE TECHNIQUE
All BSSOs included in this study were performed by 1 of 7 surgeon staff members with the assistance of a resident surgeon. Antimicrobial prophylaxis consisted
of 1 dose of intravenous (IV) amoxicillin plus clavulanate 2 g given at induction or 1 dose of IV clindamycin 600 mg for allergy to penicillin. Postoperative antibiotics were given only when bone grafts were used. All mandibular sagittal split osteotomies (SSOs) were performed with Lindemann burs (short, medium, and long; Komet, Lemgo, Germany). Five surgeons aimed for a posterior border split and made an oblique buccal osteotomy from the antegonial notch toward the distal side of the first molar.7 The other 2 surgeons performed their surgical procedures for the SSO as described by Epker8 in all cases. All bimaxillary operations started in the maxilla. After completing the SSOs at the right and left sides in the lower jaw, a final wafer was inserted and temporary intermaxillary fixation was performed. Proximal segments were positioned using bi-vector condylar seating and held in place passively with a clamp while the first screw was placed on each side. After loosening the clamp and verifying control of the occlusion, 2 more screws were placed at each side. Rigid internal fixation was established with 2.3-mm Titamed titanium bicortical screws (Titamed, Antwerp, Belgium), as described by Jeter et al9 for transbuccal placement. For transoral placement, screws were placed cranial to the nerve and perpendicular to the bone with the guidance of a von Langenbeck retractor. In some cases, the third screw was placed below the IAN, especially when the bony overlap between the proximal and distal segments was limited. Four different osteosynthesis systems were used for the placement of bicortical screws: the Titamed system, the KLS Martin system (KLS Martin GmbH, Tuttlingen, Germany), the Synthes system (Synthes GmbH, Zuchwil, Switzerland), or the Surgi-tec system (Surgi-tec, Gent, Belgium). Bony interferences were always removed on the inner side of the proximal segment by all surgeons. For transbuccal placement, bicortical screws were positioned in an inverted-L pattern through a transbuccal cannula after skin incision. Skin incisions were sutured with 5-0 Ethilon. When bicortical screws were positioned with the transoral approach, they were placed mostly in a linear formation, although adaptations sometimes occurred in the presence of a cranially positioned IAN. All intraoral wounds were sutured with polyglactin (3-0 Vicryl, Ethicon, Johnson & Johnson, Dilbeek, Belgium). No drainage was used in any case of SSO. A fibrin sealant (Tisseel, Baxter AG, Vienna, Austria) in the sagittal split wound was applied by 5 of the 7 surgeons at the end of the operation. No postsurgical intermaxillary fixation was used. Guiding elastics with light forces were applied in standard fashion to guide a patient’s occlusion during the first 6 postsurgical weeks.
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Clinical and radiographic evaluations were planned at 1, 2, and 6 weeks and at 6 and 12 months postoperatively. An infectious reaction was considered present whenever acute swelling and pain in combination with granulation tissue at the fixation site or an intraoral fistula with pus at the osteosynthesis site was observed. An inflammatory infiltration was treated with antibiotics, and an abscess was treated with incision and drainage. No wound cultures were obtained in any case. The average follow-up time was always at least 18 months. STUDY VARIABLES
The screw insertion approach (transoral vs transbuccal) was defined as the predictor variable. Data on postoperative complications, namely infection and screw removal, were analyzed as the primary outcome variables. Age, gender, surgical procedure (BSSO Le Fort I genioplasty), application of fibrin sealant (yes or no), and preoperative removal of third molars (yes or no) were incorporated as potential confounding variables. In addition, data on the type of deformity (Angle classification and presence of mandibular asymmetry) and the direction of the surgical movement of the jaw were registered for further interpretation of outcome data. Owing to the retrospective study design, sensitivity of the IAN could not be evaluated. Also, the indication for removal, the interval from surgery to the presence of postoperative complications, and the side of the complication were retrieved from the medical charts. This retrospective study acquired institutional review board approval and was conducted in compliance with Declaration of Helsinki guidelines. DATA COLLECTION, MANAGEMENT, AND ANALYSIS
All data were collected from the medical charts by the resident (B.J.F.) and recorded in an Excel (Microsoft, Redmond, WA) file. Descriptive statistics (mean, range, and frequency) were computed for patient and treatment characteristics, predictor outcomes, and confounding variables. Bivariate analyses (c2 test and Fisher exact test) were used as appropriate to measure the association between all study variables and the primary outcome variables. Binary logistic regression analysis was applied to examine the predictive value of variables that showed significant associations (P < .05) in the bivariate analysis after adjusting for potential relevant variables (age, gender, fibrin sealant, and third molar removal) that could act as confounders. Statistical evaluation was performed with IBM SPSS Statistics 20.0 for Windows (IBM Corporation, Armonk, NY). Probabilities less than .05 were accepted as significant.
Results An overview of patient and treatment characteristics is presented in Table 1. The clinical files of 606 patients were retrospectively reviewed. Twenty-nine, 28, and 40 patients were excluded from review for 2010, 2011, and 2012, respectively. The study population was comprised of 509 eligible patients (324 women [63.7%], 185 men) with an average age at surgery of 26.3 years. All 509 patients had undergone a lower jaw operation; 262 patients had a bimaxillary operation and 247 had a BSSO only. Screw-related infections were observed in 4.3% of the population. With the exception of 1 patient, all infections occurred within 6 months after the osteotomy. Of the 22 patients with infections, 12 occurred on the left side, 6 occurred on the right side, and 4 occurred bilaterally. Likewise, no significant difference in screw-related infection rate was found between the transoral (6.3%; 9 of 142) and transbuccal (3.5%; 13 of 367) screw insertion approaches (P = .16; Table 1). Most infections (12 of 22) resolved after a 5-day penicillin cure (amoxicillin 875 mg and clavulanate acid 125 mg 3 times a day). No infections were observed for bone grafts. One patient also was treated with IV antibiotics because of an insufficient response from the oral intake of penicillin. Five patients required intraoral pus drainage and placement of a small gauze under local anesthesia. In 4 patients, removal of the screws under general anesthesia was indicated after an unsuccessful primary treatment with antibiotics. Removal of the screws took place at least 3 months postoperatively. One patient required extraoral drainage of the infection. Seventeen of the 509 patients (3.3%) had at least a portion of the screws removed because they requested removal or required removal secondary to complications related to the screws (Table 1). The average time from hardware placement to removal was 8.7 months (range, 0 to 46 months). Of the removals, 82.3% occurred within the first year after the operation. Of the 17 patients with screw removal, 9 had the screws removed because a problem occurred on the left side, 5 because a problem occurred on the right side, and 3 because a problem occurred bilaterally. In 4 patients (0.8%), the screws were removed because of an infectious episode related to the presence of the screws. Seven patients (1.2%) required screw removal during revision surgery of the osteotomy to correct postoperative malocclusion related to inefficient fixation of the segment or loosening of the jaws during fixation. The positional screws were placed using the transoral approach in 4 of these 7 patients and the transbuccal approach in the other 3 patients.
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337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392
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Table 1. SUMMARY OF ALL STUDY VARIABLES VERSUS SCREW INSERTION APPROACH
Age (yr), mean (range) Gender Men Women Procedure BSSO genio Bimax genio Angle classification II III Third molars Absent before BSSO Present during BSSO Fibrin sealant Applied during surgery Not applied during surgery Primary outcome variables Screw removal Infection rate
Transoral Approach (n = 367), n (%)
Transbuccal Approach (n = 142), n (%)
Total (N = 509), n (%)
P Value
26.0 (14.0-60.0)
27.3 (14.0-59.0)
26.3 (14.0-60.0)
.24
137 (37.3) 230 (62.7)
48 (33.8) 94 (66.2)
185 (36.3) 324 (63.7)
.46
145 (39.5) 222 (60.5)
102 (71.8) 40 (28.2)
247 (48.5) 262 (51.5)
<.001
310 (84.5) 57 (15.5)
120 (84.5) 22 (15.5)
430 (84.5) 79 (15.5)
.99
361 (98.4) 6 (1.6)
142 (100) 0 (0)
503 (98.8) 6 (1.2)
.19
363 (98.9) 4 (1.1)
20 (14.1) 122 (85.9)
383 (75.2) 126 (24.8)
<.001
11 (3.0) 13 (3.5)
6 (4.2) 9 (6.3)
17 (3.3) 22 (4.3)
.49 .16
Note: Transoral approach and transbuccal approach are separately tabulated. Abbreviations: Bimax, bimaxillary osteotomy; BSSO, bilateral sagittal split osteotomy; genio, genioplasty. Falter et al. Transoral Fixation for Osteotomies. J Oral Maxillofac Surg 2016.
Three patients (0.6%) requested removal because of pain or palpable screws. Two patients (0.4%) underwent anesthesia of the third division of the trigeminal nerve directly postoperatively, necessitating removal and replacement of the osteosynthesis screws within 1 week; the 2 screws were placed transorally. The function of the nerve recuperated within 6 months. One patient had a mandibular fracture 2 months after the osteotomy that required revision of the osteotomy. Evaluation of the screw insertion approach showed a nonsignificant difference in screw removal between the transoral (3.0%; 11 of 367) and transbuccal (4.2%; 6 of 142) screw insertion groups (P = .49; Table 1). In addition to the screw insertion approach, the effect of the surgical procedure, fibrin sealant, third molar removal, age, and gender were examined as potential risk factors for postoperative complications, postoperative infection, and screw removal (Table 2). Comparison of the bimaxillary operation with the BSSO-only operation showed a significantly higher risk of postoperative complications, in particular infection, when undergoing a BSSO (6.5%) compared with a bimaxillary operation (2.3%; P = .02; Table 2). After correction for confounding parameters, such as screw insertion, fibrin sealant, and third molar removal, a trend toward a significantly higher risk of postoperative complications and infection when un-
dergoing a BSSO compared with a bimaxillary operation remained (P = .097 and P = .08, respectively; Table 3). However, the rate of screw removal was similar between the BSSO (4.5%) and the bimaxillary operation (2.3%; P = .15; Table 2). Application of fibrin sealant after wound suture showed a statistically significant trend toward a lower risk of postoperative wound infection (3.4 vs 7.1%; P = .08; Table 2); however, this was absent after the correction for confounding parameters, such as surgical procedure, screw insertion, and third molar removal (Table 3). Application of fibrin sealant showed a nonsignificant lower risk for screw removal (2.9 vs 4.7%; P = .39; Table 2). Preoperative third molar removal was performed in all but 6 patients (Table 1). Two of these 6 patients required screw removal. One patient developed a serious infection within 6 weeks postoperatively, which required removal of the osteosynthesis material and then, several months later, extraction of the third molar; the other patient developed recurrent swelling and pain 1 year after the BSSO. A significantly higher risk of screw removal and a trend toward a significantly higher risk of postoperative complications were observed when the third molars had not been removed preoperatively (P = .02 and P = .06, respectively), although this could not be attributed to screw-related infection alone (P = .23; Table 2). After
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Table 2. Cont’d
Table 2. SUMMARY OF ALL STUDY VARIABLES VERSUS PRESENCE OF POSTOPERATIVE COMPLICATIONS, INFECTIONS, AND SCREW REMOVAL AS OUTCOME VARIABLES
Presence of Outcome Variable
Presence of Outcome Variable Yes, n (%)
Q5
No, n (%)
Postoperative complications Age (yr) 27.6 26.3 Gender Men 24 (12.1) 174 (87.8) Women 11 (3.5) 300 (96.5) Surgical procedure BSSO 24 (9.7) 223 (90.3) Bimax 11 (4.2) 251 (95.8) Angle classification II 31 (7.2) 399 (92.8) III 4 (5.1) 75 (94.9) Preoperative removal of third molars Yes 33 (6.6) 470 (93.4) No 2 (33.3) 4 (66.6) Fibrin sealant Yes 21 (5.5) 361 (94.5) No 14 (11.0) 113 (89.0) Postoperative infection Age (yr) 27.8 26.3 Gender Men 6 (3.2) 179 (96.8) Women 16 (4.9) 308 (95.1) Surgical procedure BSSO 16 (6.5) 231 (93.5) Bimax 6 (2.3) 256 (97.7) Angle classification II 20 (4.7) 410 (95.3) III 2 (2.5) 77 (97.5) Preoperative removal of third molars Yes 21 (4.2) 482 (95.8) No 1 (17.7) 5 (83.3) Fibrin sealant Yes 13 (3.4) 369 (96.6) No 9 (7.1) 118 (92.9) Postoperative screw removal Age (yr) 28.4 26.3 Gender Men 7 (3.8) 178 (96.2) Women 10 (3.1) 314 (96.9) Surgical procedure BSSO 11 (4.5) 236 (95.5) Bimax 6 (2.3) 256 (97.7) Angle classification II 14 (3.3) 416 (96.7) III 3 (3.8) 76 (96.2) Preoperative removal of third molars Yes 15 (3.0) 488 (97.0) No 2 (33.3) 4 (66.7)
P Value
.94
.59
.02
.63
.06
.04 .53
.37
.02
.55
.23
.08 .44
.66
.15
.73
.02
Fibrin sealant Yes No
Yes, n (%)
No, n (%)
P Value
11 (2.9) 6 (4.7)
371 (97.1) 121 (95.3)
.39
Abbreviations: Bimax, bimaxillary osteotomy; BSSO, bilateral sagittal split osteotomy. Falter et al. Transoral Fixation for Osteotomies. J Oral Maxillofac Surg 2016.
correction for confounding parameters, such as surgical procedure, screw insertion, and fibrin sealant, this significant difference remained for screw removal and for postoperative complications (P = .002 and P = .016, respectively; Table 3). The average age in the screw removal group was 28.4 years (range, 17 to 45 yr) compared with 26.3 years (range, 14 to 60 yr) for patients in whom removal was not indicated. For the infection group, the average age was 27.8 years (range, 15 to 52 yr) compared with 26.3 years (range, 14 to 60 yr) for patients without infection. No significant age effect was found for removal rate (P = .44) or infection rate (P = .53; Table 2). Likewise, no gender effect was found for hardware removal (P = .66) or for infection risk (P = .37; Table 2). Ten women (3.1% of all women in the study) and 7 men (3.8% of all men) required screw removal. Postoperative infection was observed in 16 women (4.9%) and 6 men (3.2%; Table 2).
Discussion Many publications have reported on the incidence of complications with the transbuccal system for screw fixation, but none have reported on the transoral technique. The authors hypothesized that a transoral fixation might result in similar or possibly fewer postoperative complications than the transbuccal approach when performed by an experienced surgeon. In this retrospective study, transoral and transbuccal bicortical screw fixation during orthognathic surgery were compared for screw removal and infection rate. Moreover, the authors searched for additional risk factors indicative of these screw-related postoperative complications. Analysis of the 509 eligible patients showed that screw removal was indicated in approximately 3 of
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Table 3. BINARY LOGISTIC REGRESSION MODEL OF STUDY VARIABLES PREDICTIVE OF POSTOPERATIVE COMPLICATIONS, INFECTION, AND SCREW REMOVAL AS OUTCOME VARIABLES
Postoperative Complications Q6
Study Variables Transoral approach BSSO No fibrin sealant Preoperative removal of third molars Female gender Age
Postoperative Infection
Postoperative Screw Removal
OR (95% CI)
P Value
OR (95% CI)
P Value
OR (95% CI)
P Value
1.530 (0.27-8.73) 1.969 (0.89-4.38)* 2.692 (0.47-15.55) 0.108 (0.02-0.66)
.632 .097 .268 .016
1.536 (0.18-13.12) 2.502 (0.92-6.84)y 2.483 (0.29-21.46) 0.168 (0.02-1.64)
.70 .08 .39 .13
1.513 (0.13-17.84) 1.619 (0.55-4.79) 2.412 (0.20-28.77) 0.047 (0.01-0.31)z
.742 .384 .486 .002
1.303 (0.61-2.78) 1.012 (0.98-1.05)
.493 .442
1.597 (0.60-4.23) 1.012 (0.98-1.05)
.35 .52
0.843 (0.31-2.32) 1.024 (0.98-1.07)
.742 .268
Abbreviations: BSSO, bilateral sagittal split osteotomy; CI, confidence interval; OR, odds ratio. * Odds of having a postoperative complication after BSSO are 1.969 times greater than when undergoing a bimaxillary osteotomy and when all other variables are fixed. y Odds of having a postoperative infection after BSSO are 2.502 times greater than when undergoing a bimaxillary osteotomy and when all other variables are fixed. z Odds of requiring postoperative screw removal are 21.28 (1 of 0.047) times lower when molars are removed preoperatively and when all other variables are fixed. Falter et al. Transoral Fixation for Osteotomies. J Oral Maxillofac Surg 2016.
100 patients treated at the authors’ division. Similar screw removal rates were seen for the transoral (3.0%) and transbuccal (4.2%) approaches. This low incidence rate indicates that screw insertion is a reliable and safe technique for orthognathic procedures. Likewise, no relevant difference in infection rate was seen between the techniques (transoral vs transbuccal, 3.5 vs 6.3%). Application of fibrin sealant and preoperative removal of third molars might induce an additional protective effect against postoperative complications. However, confirmation in a prospective randomized design is required. The general infection rates of the lower jaw osteotomy of 4.2% per patient and 2.2% per osteotomy site (22 of 1,009) are similar to those reported by Spaey et al10 (4.4%), although that study investigated BSSO sites of the lower and upper jaws. Bouchard and Lalancette11 reported an infection rate of 12.6% in 174 orthognathic patients treated with bicortical screw osteosynthesis. They did not report the number of patients treated with a transbuccal or a transoral technique; however, they used a different technique with a 90 screwdriver for the intraoral placement of screws. Most infections (12 of 22) were cured after a waitand-see policy of 2 weeks with oral antibiotics. Likewise, the screw removal results are in agreement with those found in the literature, with screw removal rates of 2.8 to 14.5% when using a transbuccal approach.4-6 However, problems and infections that required screw removal seemed to start more often on the left side (10 of 17) than on the right side (5 of 17) or bilaterally (2 of 17). This might be explained in part by the fact that in most cases left osteosynthesis was performed by the resident
instead of 1 of the staff members. However, this could not be analyzed as a potential confounding factor and, hence, remains a subjective interpretation of the authors. Moreover, the authors prefer to use screws rather than monocortical miniplates for fixation of osteotomies, because in their experience this procedure is safe and reliable. The 2 procedures have been reported to offer similar skeletal stability.12,13 However, their use depends largely on the preference of the surgeon. In the present study, the authors did not observe the disadvantages seen with the use of bicortical screws, such as rotation of the mandibular condyles from compression of the proximal fragments, or risk of compression of the nerve between the bony fragments, as described by Borstlap et al.14 In addition, laboratory studies have shown that bicortical screw fixation tends to be more rigid and less susceptible to deformation than monocortical plate fixation for mandibular setback.15,16 Of the 509 patients reviewed, 7 needed a secondary operation because of relapse after surgery. The positional screws were placed in 4 patients in the transoral group (n = 367; 1.1%) and in 3 patients in the transbuccal group (n = 142; 2.1%). Although Sindel et al17 reported that their finite element analysis of the stabilization of the SSO showed that an inverted-L formation of the bicortical screws had a better stress distribution than the linear formation, the authors did not find such clinical differences in the present results. However, transoral placement of bicortical screws in a linear formation demands considerable experience in orthognathic surgery and in screw osteosynthesis. Malpositioning of the screws can cause
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anesthesia of the IAN or instability with relapse. Either complication is an indication for replacement of the screws within days after the operation. In addition to the screw insertion approach, the authors examined the effect of the surgical procedure, fibrin sealant, third molar removal, age, and gender as potential risk factors for postoperative infection or screw removal. The higher incidence in infection rate of the BSSOonly operation (6.7%) compared with the bimaxillary operation (2.2%) is an interesting finding. However, this effect was weakened after correction for screw insertion approach, application of fibrin sealant, and third molar removal. A similar situation was noted for the removal rates of 4.6 and 2.2%, respectively. Similar results have been reported by Alpha et al.18 In their study, patients who underwent bimaxillary osteotomy received several doses of IV antibiotics during their hospital stay, whereas patients who underwent only a BSSO did not. Another difference is that they used osteosynthesis plates instead of screws for the fixation of the lower jaw osteotomy. The difference in the present study might be explained by a prolonged hospital stay of 2 days for the bimaxillary operations. Patients undergoing a bimaxillary osteotomy generally start their oral intake of nutrition 12 hours later because of greater postoperative swelling. Also, patients are instructed on the importance of oral hygiene by dietitians and nurses. This might have had a protective effect that decreased the infection rate. Another reason could be that in a bimaxillary procedure, the authors try to intercept the flaring of the lower jaw that occurs in patients with a midline deviation of the mandible. By planning a small yaw correction in the upper jaw, rotation of the lower jaw can be decreased. Also, although the authors did not find a statistically meaningful smaller percentage of postoperative complications when applying the transoral approach, considerably more transoral procedures were performed in the bimaxillary surgery compared with the BSSO surgery, which—according to the authors’ hypothesis—could have led to a protective effect. In addition, because Tisseel, a fibrin sealant, has been suggested for use in adult or pediatric patients undergoing surgery as an alternative or adjunct to conventional surgical suture or ligature,10 the authors were interested in its impact on postoperative outcome for this indication. The present findings might indeed be suggestive for the use of fibrin sealant for wound sealing, because it tended to lower the risk of postoperative infectious complications (infections, 3.4%; screw removal, 2.9%)compared with osteotomies in which no fibrin sealant was used (infections, 4.7%; screw removal, 7.1%). This is in agreement
with the findings of Spaey et al10 who reported a decrease in infection rate when using perioperative application of fibrin glue instead of a drain. However, the substantial difference in the sample size of patients who were treated with fibrin sealant compared with those who were not might raise power issues. Moreover, a protective effect of fibrin sealant was no longer present after a correction for confounding factors in the logistic regression model. Further investigation in a randomized controlled trial is required to confirm this finding. Moreover, the present findings suggest that the removal of lower third molars at least 6 months before a BSSO should be standard practice. Although the lower third molars were not removed in only 6 patients, there was a considerably higher risk of screw removal in these patients, even after a correction for confounding parameters. Also, 2 of these 6 patients developed a postoperative infection. This is in agreement with the findings of Alpha et al18 who reported a higher incidence of healing disturbance in patients whose third molars were present at the time of surgery, but contrary to the findings of Posnick19 who reported no difference in the rate of infection or other complication by routinely removing third molar 6 months before surgery. Gender or age did not influence postoperative outcomes in the present study, which is in agreement with the findings of Becelli et al5 and Verweij et al.6 However, the retrospective design of this study only allows hypothesisgenerating conclusions and the results should be interpreted with caution. This study had several limitations. First, although this study included a large sample, many patients were excluded because of missing data, which is common in a retrospective study. A prospective randomized trial might be the best design to address this research hypothesis. Second, the 7 surgeons working at the division allowed the inclusion of a large sample; however, postoperative complications might be explained in part by the difference in the experience of the surgeons and slight differences in their technique. A single-surgeon study would omit this confounding variable. Third, patients undergoing 3 different surgical procedures (BSSO Le Fort I genioplasty) were included in the analysis. These procedures require slight differences in surgical technique, surgical time required to complete the procedure, and postoperative care. This also might be partly responsible for the differences observed in postoperative morbidity. Fourth, the substantially smaller number of patients treated with a transbuccal approach compared with those treated with a transoral approach might raise power issues. A prospective randomized design with an a priori sample size calculation could address this issue.
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Q7
TRANSORAL FIXATION FOR OSTEOTOMIES
In general, in the authors’ experience, bicortical screw insertion is a reliable and safe technique. When performed by an experienced surgeon, the transoral technique shows similar postoperative infection and screw removal rates as the transbuccal approach. The 2 methods provide good stability with a very low incidence of immediate postoperative relapse and a low rate of postoperative complications. However, a prospective randomized trial should be performed to confirm these results. Acknowledgment The authors express their gratitude to Lies Pottel, the clinical research coordinator of the department, for her careful reading of this report.
References 1. Lindorf HH: Sagittal ramus osteotomy with tandem screw fixation. Technique and results. J Maxillofac Surg 14:311, 1986 2. Spiessl B: Osteosynthesis in sagittal osteotomy using the Obwegeser-Dal Pont method. Fortschr Kiefer Gesichtschir 18: 145, 1974 (in German) 3. Lacey MS, Colcleugh RG: Infected screws in patients treated by mandibular sagittal split osteotomy. J Oral Maxillofac Surg 53: 510, 1995 4. Bouwman JP, Husak A, Putnam GD, et al: Screw fixation following bilateral sagittal ramus osteotomy for mandibular advancement—Complications in 700 consecutive cases. Br J Oral Maxillofac Surg 33:231, 1995 5. Becelli R, Fini G, Renzi G, et al: Complications of bicortical screw fixation observed in 482 mandibular sagittal osteotomies. J Craniofac Surg 15:64, 2004 6. Verweij JP, Houppermans PN, Mensink G, et al: Removal of bicortical screws and other osteosynthesis material that caused symptoms after bilateral sagittal split osteotomy: A retrospective study of 251 patients, and review of published papers. Br J Oral Maxillofac Surg 52:756, 2014
7. Mommaerts M, Abeloos J, De Clercq C, et al: Evaluation of the slot osteosynthesis technique in mandibular advancement. With focus on occlusion and lower lip sensibility. J Craniomaxillofac Surg 22:281, 1994 8. Epker BN: Modifications in the sagittal osteotomy of the mandible. J Oral Surg 35:157, 1977 9. Jeter TS, Van Sickels JE, Dolwick MF: Modified techniques for internal fixation of sagittal ramus osteotomies. J Oral Maxillofac Surg 42:270, 1984 10. Spaey YJ, Bettens RM, Mommaerts MY, et al: A prospective study on infectious complications in orthognathic surgery. J Craniomaxillofac Surg 33:24, 2005 11. Bouchard C, Lalancette M: Infections after sagittal split osteotomy: A retrospective analysis of 336 patients. J Oral Maxillofac Surg 73:158, 2015 12. Blomqvist JE, Isaksson S: Skeletal stability after mandibular advancement: A comparison of two rigid internal fixation techniques. J Oral Maxillofac Surg 52:1133, 1994 13. Yamashita Y, Otsuka T, Shigematsu M, et al: A long-term comparative study of two rigid internal fixation techniques in terms of masticatory function and neurosensory disturbance after mandibular correction by bilateral sagittal split ramus osteotomy. Int J Oral Maxillofac Surg 40:360, 2011 14. Borstlap WA, Stoelinga PJ, Hoppenreijs TJ, et al: Stabilisation of sagittal split advancement osteotomies with miniplates: A prospective, multicentre study with two-year follow-up. Part I. Clinical parameters. Int J Oral Maxillofac Surg 33:535, 2004 15. Peterson GP, Haug RH, Van Sickels J: A biomechanical evaluation of bilateral sagittal ramus osteotomy fixation techniques. J Oral Maxillofac Surg 63:1317, 2005 16. Brasileiro BF, Grotta-Grempel R, Ambrosano GM, et al: An in vitro evaluation of rigid internal fixation techniques for sagittal split ramus osteotomies: Setback surgery. J Oral Maxillofac Surg 70:941, 2012 17. Sindel A, Demiralp S, Colok G: Evaluation of different screw fixation techniques and screw diameters in sagittal split ramus osteotomy: Finite element analysis method. J Oral Rehabil 41: 683, 2014 18. Alpha C, O’Ryan F, Silva A, et al: The incidence of postoperative wound healing problems following sagittal ramus osteotomies stabilized with miniplates and monocortical screws. J Oral Maxillofac Surg 64:659, 2006 19. Posnick JC: Orthognathic Surgery: Principles and Practice. St Louis, MO, Elsevier, 2014, pp 478–479
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CRANIOMAXILLOFACIAL DEFORMITIES/COSMETIC SURGERY
Transoral Fixation of Bicortical Screws Is Safe and Feasible for Lower Jaw Osteotomies Bart Jozef Falter, MD, DDS,* Johan Abeloos, MD, DDS, PhD,y Calix De Clercq, MD, DDS, PhD,z Nathalie Neyt, MD, DDS,x Philippe Lamoral, MD, DDS,k and Gwen R. Swennen, MD, DDS, PhD{
Q8
Q2
Purpose:
Transoral placement of bicortical screws is a rigid fixation method in orthognathic surgery that is used less often than transbuccal placement. The aim of this study was to examine the postoperative outcome of transoral bicortical screw insertion during orthognathic surgery and to compare it with the more common transbuccal fixation technique.
Materials and Methods:
A retrospective cohort study was conducted. Clinical files of orthognathic surgical patients operated on from January 2010 through December 2012 were reviewed. Screw insertion approach (transoral vs transbuccal) was examined as a predictive variable for postoperative complications (hardware removal and infection). Type of surgery, fibrin sealant, preoperative third molar removal, and patient age and gender were analyzed as potential risk factors. Descriptive and bivariate statistics and regression analyses were performed. Of the 606 patients whose cases were reviewed, 509 patients (185 men; mean age, 26.3 11.1 yr) met the inclusion criteria. Most presented with a Class II malocclusion (84.5%). A transbuccal approach was used in 27.5% of cases, leading to a screw-related infection of 6.3%. Patients treated with a transoral technique (72.5%) had fewer infections (3.5%), but this was not statistically relevant. Screw removal was indicated in 3.3% of patients. Screw placement using the transoral and transbuccal approaches was performed in 3.0 and 4.2% of patients, respectively. Infection and screw removal rates did not differ significantly between fixation techniques (P = .16 and P = .49, respectively).
Results:
Conclusion: Q3
The present findings showed an overall low rate of screw removal and infection secondary to bicortical screw insertion during orthognathic surgery. The postoperative outcome was similar for the transoral and transbuccal approaches. Ó 2016 Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg -:1.e1-1.e8, 2016 Bicortical screws have been widely used for mandibular osteosynthesis during orthognathic surgery. Lindorf1 was the first to adapt rigid fixation with lag screws as described by Spiessl2 by placing positioning screws without compression. In this way, he prevented entrapment of the inferior alveolar nerve
(IAN). In most units, it is routine policy to retain the osteosynthesis screws after bony union unless removal is clinically indicated. Currently, the reported incidence of screw removal per patient in orthognathic surgery ranges from 2.8 to 14.5% in mandibular osteotomies secondary to a transbuccal approach.3-6
Received from Division of Maxillofacial Surgery, Department of
Bruges-Ostend av, Ruddershove 10, Bruges 8000, Belgium; e-mail:
Surgery, GH St John, Bruges-Ostend, Belgium.
[email protected]
*Resident.
Received February 8 2016
yDepartment Head. zStaff Member.
Ó 2016 Published by Elsevier Inc on behalf of the American Association of Oral
xStaff Member.
and Maxillofacial Surgeons
kStaff Member.
0278-2391/16/30609-7
Accepted July 3 2016
{Professor.
http://dx.doi.org/10.1016/j.joms.2016.07.006
Address correspondence and reprint requests to Dr Falter: Division of Maxillofacial Surgery, Department of Surgery, GH St John,
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TRANSORAL FIXATION FOR OSTEOTOMIES
Many studies have investigated the complications and fixation stability of bicortical screws placed with a transbuccal technique, which provides safe osteosynthesis in orthognathic surgery.4-6 Reported complications of the transbuccal approach include early loosening of screws, palpable screws, skeletal instability related or unrelated to a pseudoarthrosis, infection, and scar formation.4 However, although technically more demanding, the transoral approach also has been frequently applied in the authors’ center to avoid extraoral scars. Despite the obvious advantage of the redundancy of a skin incision for screw insertion in the transoral approach, there are no studies describing the transoral technique for orthognathic surgery. Moreover, no studies could be found that compared the transbuccal with the transoral approach in orthognathic surgery for postsurgical morbidity. The purpose of this retrospective study was to examine and compare screw removal and infection rate, as postoperative complications, after transoral vs transbuccal bicortical screw fixation during orthognathic surgery. The authors hypothesized a higher risk for complications in the transbuccal approach owing to the temporary extraoral communication. Moreover, the authors aimed to define risk factors indicative for these screw-related postoperative complications.
Materials and Methods STUDY DESIGN
The authors performed a retrospective cohort study. STUDY SAMPLE
The records of all consecutive patients who presented at the Division of Maxillofacial Surgery of AZ Sint-Jan Brugge-Oostende av (Bruges, Belgium) for orthognathic surgery from January 2010 through December 2012 were reviewed retrospectively. To be included in the study sample, patients had to undergo a bimaxillary osteotomy, a bilateral sagittal split ramus osteotomy (BSSO), a BSSO with a genioplasty, or a bimaxillary osteotomy with genioplasty performed by 1 of the 7 senior staff members of the division. Patients were excluded as study subjects if bone cement Norian (Synthes, Bettlach, Switzerland) or Hydroset (Stryker, Kalamazoo, MI) had been used at the osteotomy sites. Other exclusion criteria included a multisegment mandibular osteotomy, osteosynthesis with plates, no postoperative orthopantomogram available, and no data on the type of placement of the screws. OPERATIVE TECHNIQUE
All BSSOs included in this study were performed by 1 of 7 surgeon staff members with the assistance of a resident surgeon. Antimicrobial prophylaxis consisted
of 1 dose of intravenous (IV) amoxicillin plus clavulanate 2 g given at induction or 1 dose of IV clindamycin 600 mg for allergy to penicillin. Postoperative antibiotics were given only when bone grafts were used. All mandibular sagittal split osteotomies (SSOs) were performed with Lindemann burs (short, medium, and long; Komet, Lemgo, Germany). Five surgeons aimed for a posterior border split and made an oblique buccal osteotomy from the antegonial notch toward the distal side of the first molar.7 The other 2 surgeons performed their surgical procedures for the SSO as described by Epker8 in all cases. All bimaxillary operations started in the maxilla. After completing the SSOs at the right and left sides in the lower jaw, a final wafer was inserted and temporary intermaxillary fixation was performed. Proximal segments were positioned using bi-vector condylar seating and held in place passively with a clamp while the first screw was placed on each side. After loosening the clamp and verifying control of the occlusion, 2 more screws were placed at each side. Rigid internal fixation was established with 2.3-mm Titamed titanium bicortical screws (Titamed, Antwerp, Belgium), as described by Jeter et al9 for transbuccal placement. For transoral placement, screws were placed cranial to the nerve and perpendicular to the bone with the guidance of a von Langenbeck retractor. In some cases, the third screw was placed below the IAN, especially when the bony overlap between the proximal and distal segments was limited. Four different osteosynthesis systems were used for the placement of bicortical screws: the Titamed system, the KLS Martin system (KLS Martin GmbH, Tuttlingen, Germany), the Synthes system (Synthes GmbH, Zuchwil, Switzerland), or the Surgi-tec system (Surgi-tec, Gent, Belgium). Bony interferences were always removed on the inner side of the proximal segment by all surgeons. For transbuccal placement, bicortical screws were positioned in an inverted-L pattern through a transbuccal cannula after skin incision. Skin incisions were sutured with 5-0 Ethilon. When bicortical screws were positioned with the transoral approach, they were placed mostly in a linear formation, although adaptations sometimes occurred in the presence of a cranially positioned IAN. All intraoral wounds were sutured with polyglactin (3-0 Vicryl, Ethicon, Johnson & Johnson, Dilbeek, Belgium). No drainage was used in any case of SSO. A fibrin sealant (Tisseel, Baxter AG, Vienna, Austria) in the sagittal split wound was applied by 5 of the 7 surgeons at the end of the operation. No postsurgical intermaxillary fixation was used. Guiding elastics with light forces were applied in standard fashion to guide a patient’s occlusion during the first 6 postsurgical weeks.
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Clinical and radiographic evaluations were planned at 1, 2, and 6 weeks and at 6 and 12 months postoperatively. An infectious reaction was considered present whenever acute swelling and pain in combination with granulation tissue at the fixation site or an intraoral fistula with pus at the osteosynthesis site was observed. An inflammatory infiltration was treated with antibiotics, and an abscess was treated with incision and drainage. No wound cultures were obtained in any case. The average follow-up time was always at least 18 months. STUDY VARIABLES
The screw insertion approach (transoral vs transbuccal) was defined as the predictor variable. Data on postoperative complications, namely infection and screw removal, were analyzed as the primary outcome variables. Age, gender, surgical procedure (BSSO Le Fort I genioplasty), application of fibrin sealant (yes or no), and preoperative removal of third molars (yes or no) were incorporated as potential confounding variables. In addition, data on the type of deformity (Angle classification and presence of mandibular asymmetry) and the direction of the surgical movement of the jaw were registered for further interpretation of outcome data. Owing to the retrospective study design, sensitivity of the IAN could not be evaluated. Also, the indication for removal, the interval from surgery to the presence of postoperative complications, and the side of the complication were retrieved from the medical charts. This retrospective study acquired institutional review board approval and was conducted in compliance with Declaration of Helsinki guidelines. DATA COLLECTION, MANAGEMENT, AND ANALYSIS
All data were collected from the medical charts by the resident (B.J.F.) and recorded in an Excel (Microsoft, Redmond, WA) file. Descriptive statistics (mean, range, and frequency) were computed for patient and treatment characteristics, predictor outcomes, and confounding variables. Bivariate analyses (c2 test and Fisher exact test) were used as appropriate to measure the association between all study variables and the primary outcome variables. Binary logistic regression analysis was applied to examine the predictive value of variables that showed significant associations (P < .05) in the bivariate analysis after adjusting for potential relevant variables (age, gender, fibrin sealant, and third molar removal) that could act as confounders. Statistical evaluation was performed with IBM SPSS Statistics 20.0 for Windows (IBM Corporation, Armonk, NY). Probabilities less than .05 were accepted as significant.
Results An overview of patient and treatment characteristics is presented in Table 1. The clinical files of 606 patients were retrospectively reviewed. Twenty-nine, 28, and 40 patients were excluded from review for 2010, 2011, and 2012, respectively. The study population was comprised of 509 eligible patients (324 women [63.7%], 185 men) with an average age at surgery of 26.3 years. All 509 patients had undergone a lower jaw operation; 262 patients had a bimaxillary operation and 247 had a BSSO only. Screw-related infections were observed in 4.3% of the population. With the exception of 1 patient, all infections occurred within 6 months after the osteotomy. Of the 22 patients with infections, 12 occurred on the left side, 6 occurred on the right side, and 4 occurred bilaterally. Likewise, no significant difference in screw-related infection rate was found between the transoral (6.3%; 9 of 142) and transbuccal (3.5%; 13 of 367) screw insertion approaches (P = .16; Table 1). Most infections (12 of 22) resolved after a 5-day penicillin cure (amoxicillin 875 mg and clavulanate acid 125 mg 3 times a day). No infections were observed for bone grafts. One patient also was treated with IV antibiotics because of an insufficient response from the oral intake of penicillin. Five patients required intraoral pus drainage and placement of a small gauze under local anesthesia. In 4 patients, removal of the screws under general anesthesia was indicated after an unsuccessful primary treatment with antibiotics. Removal of the screws took place at least 3 months postoperatively. One patient required extraoral drainage of the infection. Seventeen of the 509 patients (3.3%) had at least a portion of the screws removed because they requested removal or required removal secondary to complications related to the screws (Table 1). The average time from hardware placement to removal was 8.7 months (range, 0 to 46 months). Of the removals, 82.3% occurred within the first year after the operation. Of the 17 patients with screw removal, 9 had the screws removed because a problem occurred on the left side, 5 because a problem occurred on the right side, and 3 because a problem occurred bilaterally. In 4 patients (0.8%), the screws were removed because of an infectious episode related to the presence of the screws. Seven patients (1.2%) required screw removal during revision surgery of the osteotomy to correct postoperative malocclusion related to inefficient fixation of the segment or loosening of the jaws during fixation. The positional screws were placed using the transoral approach in 4 of these 7 patients and the transbuccal approach in the other 3 patients.
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Q4
281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336
337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392
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Table 1. SUMMARY OF ALL STUDY VARIABLES VERSUS SCREW INSERTION APPROACH
Age (yr), mean (range) Gender Men Women Procedure BSSO genio Bimax genio Angle classification II III Third molars Absent before BSSO Present during BSSO Fibrin sealant Applied during surgery Not applied during surgery Primary outcome variables Screw removal Infection rate
Transoral Approach (n = 367), n (%)
Transbuccal Approach (n = 142), n (%)
Total (N = 509), n (%)
P Value
26.0 (14.0-60.0)
27.3 (14.0-59.0)
26.3 (14.0-60.0)
.24
137 (37.3) 230 (62.7)
48 (33.8) 94 (66.2)
185 (36.3) 324 (63.7)
.46
145 (39.5) 222 (60.5)
102 (71.8) 40 (28.2)
247 (48.5) 262 (51.5)
<.001
310 (84.5) 57 (15.5)
120 (84.5) 22 (15.5)
430 (84.5) 79 (15.5)
.99
361 (98.4) 6 (1.6)
142 (100) 0 (0)
503 (98.8) 6 (1.2)
.19
363 (98.9) 4 (1.1)
20 (14.1) 122 (85.9)
383 (75.2) 126 (24.8)
<.001
11 (3.0) 13 (3.5)
6 (4.2) 9 (6.3)
17 (3.3) 22 (4.3)
.49 .16
Note: Transoral approach and transbuccal approach are separately tabulated. Abbreviations: Bimax, bimaxillary osteotomy; BSSO, bilateral sagittal split osteotomy; genio, genioplasty. Falter et al. Transoral Fixation for Osteotomies. J Oral Maxillofac Surg 2016.
Three patients (0.6%) requested removal because of pain or palpable screws. Two patients (0.4%) underwent anesthesia of the third division of the trigeminal nerve directly postoperatively, necessitating removal and replacement of the osteosynthesis screws within 1 week; the 2 screws were placed transorally. The function of the nerve recuperated within 6 months. One patient had a mandibular fracture 2 months after the osteotomy that required revision of the osteotomy. Evaluation of the screw insertion approach showed a nonsignificant difference in screw removal between the transoral (3.0%; 11 of 367) and transbuccal (4.2%; 6 of 142) screw insertion groups (P = .49; Table 1). In addition to the screw insertion approach, the effect of the surgical procedure, fibrin sealant, third molar removal, age, and gender were examined as potential risk factors for postoperative complications, postoperative infection, and screw removal (Table 2). Comparison of the bimaxillary operation with the BSSO-only operation showed a significantly higher risk of postoperative complications, in particular infection, when undergoing a BSSO (6.5%) compared with a bimaxillary operation (2.3%; P = .02; Table 2). After correction for confounding parameters, such as screw insertion, fibrin sealant, and third molar removal, a trend toward a significantly higher risk of postoperative complications and infection when un-
dergoing a BSSO compared with a bimaxillary operation remained (P = .097 and P = .08, respectively; Table 3). However, the rate of screw removal was similar between the BSSO (4.5%) and the bimaxillary operation (2.3%; P = .15; Table 2). Application of fibrin sealant after wound suture showed a statistically significant trend toward a lower risk of postoperative wound infection (3.4 vs 7.1%; P = .08; Table 2); however, this was absent after the correction for confounding parameters, such as surgical procedure, screw insertion, and third molar removal (Table 3). Application of fibrin sealant showed a nonsignificant lower risk for screw removal (2.9 vs 4.7%; P = .39; Table 2). Preoperative third molar removal was performed in all but 6 patients (Table 1). Two of these 6 patients required screw removal. One patient developed a serious infection within 6 weeks postoperatively, which required removal of the osteosynthesis material and then, several months later, extraction of the third molar; the other patient developed recurrent swelling and pain 1 year after the BSSO. A significantly higher risk of screw removal and a trend toward a significantly higher risk of postoperative complications were observed when the third molars had not been removed preoperatively (P = .02 and P = .06, respectively), although this could not be attributed to screw-related infection alone (P = .23; Table 2). After
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Table 2. Cont’d
Table 2. SUMMARY OF ALL STUDY VARIABLES VERSUS PRESENCE OF POSTOPERATIVE COMPLICATIONS, INFECTIONS, AND SCREW REMOVAL AS OUTCOME VARIABLES
Presence of Outcome Variable
Presence of Outcome Variable Yes, n (%)
Q5
No, n (%)
Postoperative complications Age (yr) 27.6 26.3 Gender Men 24 (12.1) 174 (87.8) Women 11 (3.5) 300 (96.5) Surgical procedure BSSO 24 (9.7) 223 (90.3) Bimax 11 (4.2) 251 (95.8) Angle classification II 31 (7.2) 399 (92.8) III 4 (5.1) 75 (94.9) Preoperative removal of third molars Yes 33 (6.6) 470 (93.4) No 2 (33.3) 4 (66.6) Fibrin sealant Yes 21 (5.5) 361 (94.5) No 14 (11.0) 113 (89.0) Postoperative infection Age (yr) 27.8 26.3 Gender Men 6 (3.2) 179 (96.8) Women 16 (4.9) 308 (95.1) Surgical procedure BSSO 16 (6.5) 231 (93.5) Bimax 6 (2.3) 256 (97.7) Angle classification II 20 (4.7) 410 (95.3) III 2 (2.5) 77 (97.5) Preoperative removal of third molars Yes 21 (4.2) 482 (95.8) No 1 (17.7) 5 (83.3) Fibrin sealant Yes 13 (3.4) 369 (96.6) No 9 (7.1) 118 (92.9) Postoperative screw removal Age (yr) 28.4 26.3 Gender Men 7 (3.8) 178 (96.2) Women 10 (3.1) 314 (96.9) Surgical procedure BSSO 11 (4.5) 236 (95.5) Bimax 6 (2.3) 256 (97.7) Angle classification II 14 (3.3) 416 (96.7) III 3 (3.8) 76 (96.2) Preoperative removal of third molars Yes 15 (3.0) 488 (97.0) No 2 (33.3) 4 (66.7)
P Value
.94
.59
.02
.63
.06
.04 .53
.37
.02
.55
.23
.08 .44
.66
.15
.73
.02
Fibrin sealant Yes No
Yes, n (%)
No, n (%)
P Value
11 (2.9) 6 (4.7)
371 (97.1) 121 (95.3)
.39
Abbreviations: Bimax, bimaxillary osteotomy; BSSO, bilateral sagittal split osteotomy. Falter et al. Transoral Fixation for Osteotomies. J Oral Maxillofac Surg 2016.
correction for confounding parameters, such as surgical procedure, screw insertion, and fibrin sealant, this significant difference remained for screw removal and for postoperative complications (P = .002 and P = .016, respectively; Table 3). The average age in the screw removal group was 28.4 years (range, 17 to 45 yr) compared with 26.3 years (range, 14 to 60 yr) for patients in whom removal was not indicated. For the infection group, the average age was 27.8 years (range, 15 to 52 yr) compared with 26.3 years (range, 14 to 60 yr) for patients without infection. No significant age effect was found for removal rate (P = .44) or infection rate (P = .53; Table 2). Likewise, no gender effect was found for hardware removal (P = .66) or for infection risk (P = .37; Table 2). Ten women (3.1% of all women in the study) and 7 men (3.8% of all men) required screw removal. Postoperative infection was observed in 16 women (4.9%) and 6 men (3.2%; Table 2).
Discussion Many publications have reported on the incidence of complications with the transbuccal system for screw fixation, but none have reported on the transoral technique. The authors hypothesized that a transoral fixation might result in similar or possibly fewer postoperative complications than the transbuccal approach when performed by an experienced surgeon. In this retrospective study, transoral and transbuccal bicortical screw fixation during orthognathic surgery were compared for screw removal and infection rate. Moreover, the authors searched for additional risk factors indicative of these screw-related postoperative complications. Analysis of the 509 eligible patients showed that screw removal was indicated in approximately 3 of
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Table 3. BINARY LOGISTIC REGRESSION MODEL OF STUDY VARIABLES PREDICTIVE OF POSTOPERATIVE COMPLICATIONS, INFECTION, AND SCREW REMOVAL AS OUTCOME VARIABLES
Postoperative Complications Q6
Study Variables Transoral approach BSSO No fibrin sealant Preoperative removal of third molars Female gender Age
Postoperative Infection
Postoperative Screw Removal
OR (95% CI)
P Value
OR (95% CI)
P Value
OR (95% CI)
P Value
1.530 (0.27-8.73) 1.969 (0.89-4.38)* 2.692 (0.47-15.55) 0.108 (0.02-0.66)
.632 .097 .268 .016
1.536 (0.18-13.12) 2.502 (0.92-6.84)y 2.483 (0.29-21.46) 0.168 (0.02-1.64)
.70 .08 .39 .13
1.513 (0.13-17.84) 1.619 (0.55-4.79) 2.412 (0.20-28.77) 0.047 (0.01-0.31)z
.742 .384 .486 .002
1.303 (0.61-2.78) 1.012 (0.98-1.05)
.493 .442
1.597 (0.60-4.23) 1.012 (0.98-1.05)
.35 .52
0.843 (0.31-2.32) 1.024 (0.98-1.07)
.742 .268
Abbreviations: BSSO, bilateral sagittal split osteotomy; CI, confidence interval; OR, odds ratio. * Odds of having a postoperative complication after BSSO are 1.969 times greater than when undergoing a bimaxillary osteotomy and when all other variables are fixed. y Odds of having a postoperative infection after BSSO are 2.502 times greater than when undergoing a bimaxillary osteotomy and when all other variables are fixed. z Odds of requiring postoperative screw removal are 21.28 (1 of 0.047) times lower when molars are removed preoperatively and when all other variables are fixed. Falter et al. Transoral Fixation for Osteotomies. J Oral Maxillofac Surg 2016.
100 patients treated at the authors’ division. Similar screw removal rates were seen for the transoral (3.0%) and transbuccal (4.2%) approaches. This low incidence rate indicates that screw insertion is a reliable and safe technique for orthognathic procedures. Likewise, no relevant difference in infection rate was seen between the techniques (transoral vs transbuccal, 3.5 vs 6.3%). Application of fibrin sealant and preoperative removal of third molars might induce an additional protective effect against postoperative complications. However, confirmation in a prospective randomized design is required. The general infection rates of the lower jaw osteotomy of 4.2% per patient and 2.2% per osteotomy site (22 of 1,009) are similar to those reported by Spaey et al10 (4.4%), although that study investigated BSSO sites of the lower and upper jaws. Bouchard and Lalancette11 reported an infection rate of 12.6% in 174 orthognathic patients treated with bicortical screw osteosynthesis. They did not report the number of patients treated with a transbuccal or a transoral technique; however, they used a different technique with a 90 screwdriver for the intraoral placement of screws. Most infections (12 of 22) were cured after a waitand-see policy of 2 weeks with oral antibiotics. Likewise, the screw removal results are in agreement with those found in the literature, with screw removal rates of 2.8 to 14.5% when using a transbuccal approach.4-6 However, problems and infections that required screw removal seemed to start more often on the left side (10 of 17) than on the right side (5 of 17) or bilaterally (2 of 17). This might be explained in part by the fact that in most cases left osteosynthesis was performed by the resident
instead of 1 of the staff members. However, this could not be analyzed as a potential confounding factor and, hence, remains a subjective interpretation of the authors. Moreover, the authors prefer to use screws rather than monocortical miniplates for fixation of osteotomies, because in their experience this procedure is safe and reliable. The 2 procedures have been reported to offer similar skeletal stability.12,13 However, their use depends largely on the preference of the surgeon. In the present study, the authors did not observe the disadvantages seen with the use of bicortical screws, such as rotation of the mandibular condyles from compression of the proximal fragments, or risk of compression of the nerve between the bony fragments, as described by Borstlap et al.14 In addition, laboratory studies have shown that bicortical screw fixation tends to be more rigid and less susceptible to deformation than monocortical plate fixation for mandibular setback.15,16 Of the 509 patients reviewed, 7 needed a secondary operation because of relapse after surgery. The positional screws were placed in 4 patients in the transoral group (n = 367; 1.1%) and in 3 patients in the transbuccal group (n = 142; 2.1%). Although Sindel et al17 reported that their finite element analysis of the stabilization of the SSO showed that an inverted-L formation of the bicortical screws had a better stress distribution than the linear formation, the authors did not find such clinical differences in the present results. However, transoral placement of bicortical screws in a linear formation demands considerable experience in orthognathic surgery and in screw osteosynthesis. Malpositioning of the screws can cause
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anesthesia of the IAN or instability with relapse. Either complication is an indication for replacement of the screws within days after the operation. In addition to the screw insertion approach, the authors examined the effect of the surgical procedure, fibrin sealant, third molar removal, age, and gender as potential risk factors for postoperative infection or screw removal. The higher incidence in infection rate of the BSSOonly operation (6.7%) compared with the bimaxillary operation (2.2%) is an interesting finding. However, this effect was weakened after correction for screw insertion approach, application of fibrin sealant, and third molar removal. A similar situation was noted for the removal rates of 4.6 and 2.2%, respectively. Similar results have been reported by Alpha et al.18 In their study, patients who underwent bimaxillary osteotomy received several doses of IV antibiotics during their hospital stay, whereas patients who underwent only a BSSO did not. Another difference is that they used osteosynthesis plates instead of screws for the fixation of the lower jaw osteotomy. The difference in the present study might be explained by a prolonged hospital stay of 2 days for the bimaxillary operations. Patients undergoing a bimaxillary osteotomy generally start their oral intake of nutrition 12 hours later because of greater postoperative swelling. Also, patients are instructed on the importance of oral hygiene by dietitians and nurses. This might have had a protective effect that decreased the infection rate. Another reason could be that in a bimaxillary procedure, the authors try to intercept the flaring of the lower jaw that occurs in patients with a midline deviation of the mandible. By planning a small yaw correction in the upper jaw, rotation of the lower jaw can be decreased. Also, although the authors did not find a statistically meaningful smaller percentage of postoperative complications when applying the transoral approach, considerably more transoral procedures were performed in the bimaxillary surgery compared with the BSSO surgery, which—according to the authors’ hypothesis—could have led to a protective effect. In addition, because Tisseel, a fibrin sealant, has been suggested for use in adult or pediatric patients undergoing surgery as an alternative or adjunct to conventional surgical suture or ligature,10 the authors were interested in its impact on postoperative outcome for this indication. The present findings might indeed be suggestive for the use of fibrin sealant for wound sealing, because it tended to lower the risk of postoperative infectious complications (infections, 3.4%; screw removal, 2.9%)compared with osteotomies in which no fibrin sealant was used (infections, 4.7%; screw removal, 7.1%). This is in agreement
with the findings of Spaey et al10 who reported a decrease in infection rate when using perioperative application of fibrin glue instead of a drain. However, the substantial difference in the sample size of patients who were treated with fibrin sealant compared with those who were not might raise power issues. Moreover, a protective effect of fibrin sealant was no longer present after a correction for confounding factors in the logistic regression model. Further investigation in a randomized controlled trial is required to confirm this finding. Moreover, the present findings suggest that the removal of lower third molars at least 6 months before a BSSO should be standard practice. Although the lower third molars were not removed in only 6 patients, there was a considerably higher risk of screw removal in these patients, even after a correction for confounding parameters. Also, 2 of these 6 patients developed a postoperative infection. This is in agreement with the findings of Alpha et al18 who reported a higher incidence of healing disturbance in patients whose third molars were present at the time of surgery, but contrary to the findings of Posnick19 who reported no difference in the rate of infection or other complication by routinely removing third molar 6 months before surgery. Gender or age did not influence postoperative outcomes in the present study, which is in agreement with the findings of Becelli et al5 and Verweij et al.6 However, the retrospective design of this study only allows hypothesisgenerating conclusions and the results should be interpreted with caution. This study had several limitations. First, although this study included a large sample, many patients were excluded because of missing data, which is common in a retrospective study. A prospective randomized trial might be the best design to address this research hypothesis. Second, the 7 surgeons working at the division allowed the inclusion of a large sample; however, postoperative complications might be explained in part by the difference in the experience of the surgeons and slight differences in their technique. A single-surgeon study would omit this confounding variable. Third, patients undergoing 3 different surgical procedures (BSSO Le Fort I genioplasty) were included in the analysis. These procedures require slight differences in surgical technique, surgical time required to complete the procedure, and postoperative care. This also might be partly responsible for the differences observed in postoperative morbidity. Fourth, the substantially smaller number of patients treated with a transbuccal approach compared with those treated with a transoral approach might raise power issues. A prospective randomized design with an a priori sample size calculation could address this issue.
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In general, in the authors’ experience, bicortical screw insertion is a reliable and safe technique. When performed by an experienced surgeon, the transoral technique shows similar postoperative infection and screw removal rates as the transbuccal approach. The 2 methods provide good stability with a very low incidence of immediate postoperative relapse and a low rate of postoperative complications. However, a prospective randomized trial should be performed to confirm these results. Acknowledgment The authors express their gratitude to Lies Pottel, the clinical research coordinator of the department, for her careful reading of this report.
References 1. Lindorf HH: Sagittal ramus osteotomy with tandem screw fixation. Technique and results. J Maxillofac Surg 14:311, 1986 2. Spiessl B: Osteosynthesis in sagittal osteotomy using the Obwegeser-Dal Pont method. Fortschr Kiefer Gesichtschir 18: 145, 1974 (in German) 3. Lacey MS, Colcleugh RG: Infected screws in patients treated by mandibular sagittal split osteotomy. J Oral Maxillofac Surg 53: 510, 1995 4. Bouwman JP, Husak A, Putnam GD, et al: Screw fixation following bilateral sagittal ramus osteotomy for mandibular advancement—Complications in 700 consecutive cases. Br J Oral Maxillofac Surg 33:231, 1995 5. Becelli R, Fini G, Renzi G, et al: Complications of bicortical screw fixation observed in 482 mandibular sagittal osteotomies. J Craniofac Surg 15:64, 2004 6. Verweij JP, Houppermans PN, Mensink G, et al: Removal of bicortical screws and other osteosynthesis material that caused symptoms after bilateral sagittal split osteotomy: A retrospective study of 251 patients, and review of published papers. Br J Oral Maxillofac Surg 52:756, 2014
7. Mommaerts M, Abeloos J, De Clercq C, et al: Evaluation of the slot osteosynthesis technique in mandibular advancement. With focus on occlusion and lower lip sensibility. J Craniomaxillofac Surg 22:281, 1994 8. Epker BN: Modifications in the sagittal osteotomy of the mandible. J Oral Surg 35:157, 1977 9. Jeter TS, Van Sickels JE, Dolwick MF: Modified techniques for internal fixation of sagittal ramus osteotomies. J Oral Maxillofac Surg 42:270, 1984 10. Spaey YJ, Bettens RM, Mommaerts MY, et al: A prospective study on infectious complications in orthognathic surgery. J Craniomaxillofac Surg 33:24, 2005 11. Bouchard C, Lalancette M: Infections after sagittal split osteotomy: A retrospective analysis of 336 patients. J Oral Maxillofac Surg 73:158, 2015 12. Blomqvist JE, Isaksson S: Skeletal stability after mandibular advancement: A comparison of two rigid internal fixation techniques. J Oral Maxillofac Surg 52:1133, 1994 13. Yamashita Y, Otsuka T, Shigematsu M, et al: A long-term comparative study of two rigid internal fixation techniques in terms of masticatory function and neurosensory disturbance after mandibular correction by bilateral sagittal split ramus osteotomy. Int J Oral Maxillofac Surg 40:360, 2011 14. Borstlap WA, Stoelinga PJ, Hoppenreijs TJ, et al: Stabilisation of sagittal split advancement osteotomies with miniplates: A prospective, multicentre study with two-year follow-up. Part I. Clinical parameters. Int J Oral Maxillofac Surg 33:535, 2004 15. Peterson GP, Haug RH, Van Sickels J: A biomechanical evaluation of bilateral sagittal ramus osteotomy fixation techniques. J Oral Maxillofac Surg 63:1317, 2005 16. Brasileiro BF, Grotta-Grempel R, Ambrosano GM, et al: An in vitro evaluation of rigid internal fixation techniques for sagittal split ramus osteotomies: Setback surgery. J Oral Maxillofac Surg 70:941, 2012 17. Sindel A, Demiralp S, Colok G: Evaluation of different screw fixation techniques and screw diameters in sagittal split ramus osteotomy: Finite element analysis method. J Oral Rehabil 41: 683, 2014 18. Alpha C, O’Ryan F, Silva A, et al: The incidence of postoperative wound healing problems following sagittal ramus osteotomies stabilized with miniplates and monocortical screws. J Oral Maxillofac Surg 64:659, 2006 19. Posnick JC: Orthognathic Surgery: Principles and Practice. St Louis, MO, Elsevier, 2014, pp 478–479
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