Optimization of mandibular fracture treatment
Batbayar, Enkh-Orchlon
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Batbayar, E-O. (2019). Optimization of mandibular fracture treatment. University of Groningen.
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A TREATMENT PROTOCOL FOR
FRACTURES OF THE EDENTULOUS
MANDIBLE
Enkh-Orchlon Batbayar,Ruud R.M.Bos, Baucke van Minnen J Oral Maxillofac Surg. 2018 Oct;76(10):2151-2160.
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ABSTRACT
Purpose. The incidence of fractures of edentulous mandibles is relatively low. The knowledge about the management of these fractured edentulous mandibles relies heavily upon case reports and observational studies. Based on current literature, we compiled a treatment protocol for fractures of the edentulous mandible and hypothesized that this protocol results in fewer complications.
Patients and Methods. We conducted a retrospective cohort study of edentulous patients with a mandibular fracture. The predictor variable was the fulfillment of the treatment protocol (yes, no). The outcome variables were postoperative complications and reoperation. Demographic variables of patients were collected from patient’s records. A chi-square test was used for statistical analysis between predictor and outcome variables.
Results. Of 61 edentulous mandibular fractures (36 patients), 53 fractures were treated according to the protocol and 8 were not. Four complications were observed first group in the (complication rate 4/53=7.5%) and four in the second group (complication rate 4/8=50%). The fracture treatments that followed the protocol had a significantly (p=.001, OR=.082) lower postoperative complication rate, and needed fewer reoperations (p=.0001, OR=.019) compared with the treatments that did not follow the protocol.
Conclusion. The results of this study show that following the compiled treatment protocol for fractures of edentulous mandibles significantly reduces postoperative complications and reoperations.
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INTRODUCTION
The incidence of fractures of edentulous atrophic mandibles is relatively low. 1 The
knowledge about the management of these fractures relies heavily upon case reports and observational or retrospective studies.2 Moreover, a systematic
Cochrane review did not provide sufficient evidence for the best treatment of these fractures and concluded that treatment decisions are mainly based on clinician’s experience.6
Several factors need to be considered to treat patients with edentulous mandibular fractures, such as comorbidities, age, fracture type and particularly residual bone height at the fracture site. Some clinicians state that it is preferable to treat severely atrophic mandibular fractures with a combination of an autogenous bone graft and a load bearing plate.8,9 However, different
theories have been proposed regarding the use of sharing or load-bearing principles in these fractures. Load-load-bearing plates without bone graft are advocated by some authors because this method is less invasive.4,5,9
Based on current literature and with our experiences, we compiled a treatment protocol (Fig.1) for fractures of the edentulous mandible. The aim of this study was to evaluate the effect of the treatment protocol for edentulous mandibular fractures on complication rates and number of reoperations.
METHODS
In a retrospective cohort study, we included all edentulous mandibular fracture cases which were treated at Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, the Netherlands from January 2007 to December 2016. Due to its retrospective nature, this study was exempted of approval by the ethical review board of the University Medical Center Groningen. Edentulous individuals that received surgical or non-surgical treatment for a mandibular fracture were included. Patients were excluded who received initial treatment at other hospitals, when pre or post treatment radiographs were missing, and when follow-up was less than three months. Based on the type of fracture and the height of the mandible, a treatment protocol was compiled (Fig 1).3,8,10–13 This protocol was not consistently
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Fig 1.
T
reatment pr
6
was divided into two groups dependent on whether the treatment protocol was followed or not. The predictor variable was the fulfillment of the treatment protocol (followed, not followed) and the outcome variables were postoperative complications (yes, no) and reoperations (yes, no).
The following information was obtained from the electronic database of the university hospital: age, gender, comorbidities, wearing of dentures (regular or implant-retained), smoking habits, alcohol and drug addiction, concomitant fracture(s), cause of trauma, fracture location, fracture type and dislocation, treatment protocol, treatment modalities, type of fixation materials, vertical bone height, hospitalization time, follow-up duration, post-treatment complications, and reoperations. All patients received perioperative prophylactic antibiotics of variable duration.
Observed complications were recorded and divided into major and minor complications. Major complications included those that require reoperation. All other complications that were treated without surgical intervention were classified as minor. The vertical height of the fracture site was measured in millimeters from upper to lower border using a panoramic radiograph. The condylar fractures were classified using the classification of Loukota et al.14
AO (Arbeitsgemeinschaft für Osteosynthesefragen) terminology was used for defining the fracture types.15 A simple fracture has a single fracture line
producing 2 fracture fragments. A comminuted fracture has multiple fracture lines in the same anatomic location resulting in multiple fragments of bone. In an incomplete fracture, the fractures do not extend through both the buccal and the lingual cortices, as well as the alveolar and basal borders. In such cases, the fracture will be nondisplaced and nonmobile. Displacement: the fracture fragments are not anatomically aligned. Displacement is graded roughly as minimal, moderate and severe. However, there is no universally accepted definition for these terms.
Data were statistically analysed with IBM SPSS version 23.0.03 software. Statistical significance was set at p< .05 and the chi-square exact test was used to analyze differences.
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RESULTS
Demographics of patients and fractures
During the study period, 42 edentulous patients with a mandibular fracture were identified. Six patients were excluded: in four patients follow-up was less than three months, from one patient radiographs were missing, and one patient was not intitially treated in our hospital. A total of 36 patients who had 61 mandibular fractures were included this study. Patients’ mean age was 66±13 years (range 42-95 years). Nineteen (52.8%) patients were male, and 17 (47.2%) female. A mean follow-up was 6.3±4 months (range 3-21 months). Fractures were caused by falls (n=9, 25%), assaults (n=8, 22%), vehicle accidents, including motor vehicles, bicycle and electronic bicycle (n=6, 16%). In seven (19%) patients the fracture occurred after the insertion of a dental implant, and in one patient (3%) the mandible fractured due to infection of a transmandibular implant which had been implanted 25 years before. The remaining patients had pathologic fractures due to osteomyelitis (n=2, 6%), fracture due to a complicated third molar extraction (n=1, 3%), spontaneous fracture during chewing with an ill-fitting denture (n=1, 3%), and fracture due to a collision with a cow (n=1, 3%).
Table 1. Fracture characteristics (n=61)
Mean vertical bone
height* 13.1±6.5 mm n (%) Location Parasymphyseal 22 (36.1) Body 16 (26.2) Angle 5 (8.2) Ramus 2 (3.3) High condyle 13 (21.5) Low condyle 3 (5.0) Type Simple 54 (88.5) Comminuted 4 (6.5) Incomplete 3 (5.0) Displacement No 31 (51.0) Yes 30 (49.0) Vertical bone height (mm)* ≤10 mm >10 mm 19 (44.0) 24 (56.0) Complications No 53 (87.0) Minor 1 (1.5) Major 7 (11.5) Reoperation Yes 5 (8.2) No 56 (91.8)
*Ramus and condylar fractures (18 fractures) were not counted
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Concomitant fractures were present in 10 patients (27.8%). Of these patients, 4 patients had polytrauma (long bone fractures), 3 had maxillary fractures, 2 had fractures of the maxillary sinus, and 1 had orbital an orbital floor fracture. Comorbidities occurred in 40 patients (83.4%). Hypertension, alcohol and drug abuse, chronic obstructive pulmonary disease, osteoporosis, and malnutrition were most frequently observed.
Mandibular fractures were mostly located in the parasymphyseal region, followed by the body region. General characteristics of fractures are shown in Table 1. Before treatment 19 patients did not wear any prosthesis, 15 patients had a removable denture, and two patients had implant-supported dentures. In total, eight fracture cases occurred after the insertion of implants (iatrogenic). After the fractures were treated, six of the patients received a new implant-supported prosthesis using the remaining implants or a new prosthesis after insertion of a new implant near the fracture location (Fig 2).
Treatment modalities
Of 61 fractures, 31(51%) underwent open reduction and internal fixation (ORIF). The remaining 30 fractures were treated in a closed manner (Table 2). In total, 27 treatments used load-sharing plates (2.0 mm mini-plates), 11
Table 2. Treatment modalities according to the treatment protocol (n=61)
Variables Treatment protocol Bone height ≤10 mm (n=12) Bone height > 10 mm (n=17) Low condylar fracture (n=4) High condylar fracture or Ramus (n=14) Non displaced and non-mobility or incomplete (n=6) Non displaced Implant related fracture (n=7) Displaced Implant related fracture (n=1) Treatment modalities Bone graft and load bearing plate 6 (50%) 1 (6%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 1 (100%) Load sharing or load bearing plate only 4 (33%) 16 (94%) 3 (75%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) Closed 2 (17%) 0 (0%) 1 (25%) 14 (100%) 6 (100%) 7 (100%) 0 (0%) Complication Yes No 39 (75%) a (25%) 314 (82%) 4 (100%) 14 (100%) 6 (100%) b (18%) 0 (0%) 0 (0%) 0 (0%) 16 (86%) c (14%) 10 (0%) d (100%) Re-operation Yes 3 (25%) 1 (6%) 0 (0%) 0 (0%) 0 (0%) 0 (0%) 1 (100%) No 9 (75%) 16 (94%) 4 (100%) 14 (100%) 6 (100%) 5 (100%) 0 (0%) Protocol followed Yes No 5 (42%) 7 (58%) 17 (100%) 4(100%) 0 (0%) 0 (0%) 14(100%) 6 (100%) 0 (0%) 0 (0%) 7 (100%) 0 (0%) 0 (0%) 1 (100%)
a Non-union (n=2), re-dislocation of the fracture (n=1)
b Osteomyelitis (n=1), wound dehiscence (n=1), plate fracture (n=1)
c Pseudarthrosis (n=1)
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Fig 2. A, Postoperative panoramic radiograph after insertion of 3 implants in a severely atrophic
mandible. B, Fracture in the left parasymphyseal area (arrow) with loss of 1 implant 1 month later. C, Result 8 months after closed treatment and insertion of a new implant.
A
B
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treatments used load-bearing plates (2.3 mm, n=8; Pape-Gerlach, n=2; or 2.7mm, n=1), and a combination of load-bearing and load-sharing plates were used in 3 cases (2.3 mm plus 2.0 mm). Bone grafts were used in 8 fractures in combination with load-bearing plates and circum-mandibular wiring. All bone grafts were harvested from the iliac crest and positioned along the lower border of the fracture. In 24 (77.5%) fractures, reduction was achieved by manual reduction, and 7 fractures (22.5%) were reduced by repositioning forceps. After treatment, 7 patients did not wear a denture until the end of follow-up. Twelve patients had a new removable partial denture, 5 patients used their old removable partial denture, 11 patients had implant-supported denture, and 1 patient underwent a Rohner procedure.16,17 Patients started to
wear their prosthesis at a mean of 4.5±3.5 months after treatment.
Treatment protocol
In 8 out of 61 fractures (13%), treatment was not performed according to the protocol. In all 8 fractures, the vertical bone height was less than 10 mm or less (Table 3). Among them, 4 fractures were treatedwith ORIF without bone grafts. Two fractures underwent fixation with a load-bearing plate and with a bone graft but not with a sufficient number of screws (Fig 3). Two cases were treated in a closed manner. In 1 case this was because the patient refused to undergo an operation, and in the second case the patient’s general health condition was a strict contraindication for surgery.
Table 3. Characteristics of fractures in which the treatment protocol was not followed
№ Gender/
Age (years) Fracture location Vertical bone height (mm)
Management Comment Complications
1 Male, 61 Body 5.00 2.3 mm plate Bone graft was necessary Non-union with plate loosening 2 Male, 61 Body 5.08 2.3 mm plate and
2.00 mm plates Bone graft was necessary Non-union with screw loosening 3 Male, 74
Para-symphysis 7.70 Bone graft with 2.3 mm plate Bone graft was done, but 2 screws on the proximal side of fracture
Re-dislocation of the fracture 4 Female, 73
Para-symphysis 5.00 Bone graft with Pape-Gerlach plates
Bone graft was done, but 2 screws on the proximal side of fracture
Osteomyelitis 5 Female, 72 Body 5.00 2.0 mm plates Bone graft and load bearing
plate was necessary No 6 Female, 79 Body 8.00 2.7 mm plate Bone graft was necessary No 7 Female, 85 Body 9.10 Closed Bone graft and load bearing
plate was necessary No 8 Female, 65 Body 8.75 Closed Bone graft and load bearing
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Fig 3. A, Postoperative panoramic radiograph showing the right-sided body fracture of a severely
atrophic mandible with fixated a bone graft, 2.3 mm plate, and circum-mandibular wiring. B, Redislocation of the fracture (arrow) probably occurred because only 2 screws had been inserted on the proximal side of the fracture
Complication and reoperation
Of 61 fractures, 53 did not show any complications. Complications occurred in 8 fractures (13%). One originally nondisplaced implant-related fracture of an edentulous irradiated mandible became displaced during follow-up. The patient did not undergo surgery because there were no complaints. Therefore, this case was classified as a minor complication.Major complications occurred in 7 fracture cases, including osteomyelitis (n=2), nonunion (n=2), wound dehiscence (n=1), plate fracture (n=1), and redislocation of the fracture (n=1). Of the complications, 4 occurred in the group in which the treatment protocol was correctly followed (complication rate, 7.5% [4 of 53]); the remaining 4 complications occurred in the group of fractures not treated according to the protocol (complication rate, 50% [4 of 8]). As shown in Table 4, complications occurred significantly more often when the fracture treatment was not performed according to the protocol.
A total of 19 fractures occurred in severely atrophic (≤10 mm) mandibles. In 11 of these fractures, the treatment protocol was followed and no complications occurred. However, in 8 fractures the treatment protocol was not followed, and major complications occurred in 4 of them (50%). A significant difference was found between these two groups (p=.018, OR=2, 95% CI 2:4).
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Table 5. Two-by-two Table between the fulfillment of protocol and reoperations
Re-operation Total Protocol Yes No
Yes 1 (2%) 52 (98%) 53 (100%) No 4 (50%) 4 (50%) 8 (100%) Total 5 (8%) 56 (92%) 61 (100%)
P value .0001, OR=.019 (95% CI, .002:.215)
Table 4. Two-by-two table between the fulfillment of protocol and complications
Complication Total
Protocol Yes No
Yes 4 (7.5%) 49 (92.5%) 53 (100%)
No 4 (50%) 4 (50%) 8 (100%)
Total 8 (13%) 53 (87%) 61 (100%)
P value .001, OR=.082 (95% CI, .015:.456)
Of 8 compilations, 5 resulted in an indication for reoperation. Of these fractures, 2 originally underwent fixation with bone grafts and load-bearing plates (Fig 3), 2 underwent fixation without bone grafts and both bearing and load-sharing plates (Fig 4), and 1 underwent fixation with a load-load-sharing plate only.
Table 5 shows that significantly fewer reoperations were necessary when the protocol was followed.
Confounders
The possible confounding factors for complications are summarized in Table 6. No association between complication and potential confounders was found.
DISCUSSION
The aim of the current study was to assess the importance of following a treatment protocol for fractures of the edentulous mandible. The results of this study suggest that fractures of edentulous mandibles treated according to the treatment protocol have fewer complications. The treatment protocol (shown in Fig. 1) was compiled based on current literature and retrospecitvely applied to our total cohort. This protocol supports the strategy of an invasive approach (i.e. bone grafting combined with load bearing plate) for fractures of the atrophic mandible with a height of 10 mm or lower, and a less invasive for fractures of the edentulous mandible with sufficient bone height of more than 10 mm.
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Fig 4. A, Postoperative panoramic radiograph showing fixation of severely atrophic mandibular
fractures using load-bearing and load-sharing plates without bone grafts. After 1.5 months, redislocation (arrows) occurred. B, Open reduction and internal fixation after reoperation with autogenous bone grafts and load-bearing plates in same patient.
The treatment protocol was not followed in a total of eight fractures although in all these fractures bone height was less than 10 mm. Four of them presented major complications such as nonunion, osteomyelitis and re-dislocation of the fracture. Nonunion and osteomyelitis is the most common complication when fractures of severely atrophic mandibles are treated without bone grafts.2,3
Furthermore, several studies have shown the importance of the number of screws on each side of the fracture.10,11,18 These studies suggested that at
A
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least 3 screws should be used on both sides of a fracture. In our study, 2 of the complications occurred probably because of lack of at least 3 screws at the proximal side of the fracture (2 screws inserted).
Fractures of the edentulous mandible with more than 10 mm bone height at the fracture site were mainly treated with ORIF without bone grafts. However, one pathologic fracture with a continuity defect was treated with load-bearing osteosynthesis with an autogenous bone graft. In fractures higher than 10 mm bone height, load-sharing plates can be used without bone graft in cases with good interfragmentary stability, while load-bearing plates can be used without bone graft in cases without sufficient interfragmentary stability.
Table 6. Potential confounders of complication
Variables Complications P value*
Yes
n (%)a No n (%)a
Gender
(n=36 Patients) Male Female 5 (26) 2 (12) 14 (74) 15 (88) .408 Co-morbidity** (n=36 Patients) Yes No 4 (13) 3 (50) 26 (87) 3 (50) .073 Concomitant fracture (n=36 Patients) Yes 4 (40) 6 (60) .076 No 3 (12) 23 (88) Bone height at fracture line (n=43 fractures) <10 mm 4 (17) 15 (83) >.99 >10 mm 4 (21) 20 (79) Fracture location b
(n=61 Fractures) Anterior Posterior 7 (18) 1 (4) 31 (82) 22 (96) .143 Fracture Displacement (n=61 Fractures) Yes 6 (20) 24 (80) .147 No 2 (7) 29 (93) Fracture type
(n=61 Fractures) Simple Complex 6 (11) 2 (50) 48 (89) 2 (50) .067 Incomplete 0 (0) 3 (100)
Fracture fixation
(n=31 Fractures) Load sharing 3 (18) 14 (82) .851 Load
bearing 3 (27) 8 (73) Both 1 (33) 2 (67)
Bone graft Yes 2 (25) 6 (75) .581 No 6 (11) 47 (89)
a Row percentage
b Anterior (symphyseal, parasymphyseal, body), Posterior (angle, ramus, condyle) *Results of Chi square test (exact procedure)
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In our study 19 out of 61 fractures occurred in severely atrophic (<10 mm) mandibles. The severely atrophic mandibles that were not treated according to the protocol presented major complications twice as often as fractures treated according to the protocol.
Fractures of the atrophic mandible occurring after implant insertion are rarely reported.19,20,12 In the current study, eight mandibular fractures occurred after
the insertion of an implant. All these fractures were treated closed, except one severely dislocated fracture case. This shows that closed treatment can result in uncomplicated healing in case there is no or just minor dislocation, and there is even agreement among some authors, who suggest closed treatment for implant related fractures of atrophic mandibles.12,21 One severely dislocated
fracture after implant placement was initially treated with an autogenous bone graft and load bearing plate. However, because of osteomyelitis, this case needed re-operation through a Rohner procedure.16,17 Eventually, 3/4 of these
patients received an implant-supported prosthesis on the remaining implants or after re-insertion of an implant. High condylar fractures and non-displaced or incomplete fractures were all treated closed, and no complications were observed.
A possible limitation of the current study is that the vertical height at the fracture site was measured using the OPG, which may result in magnification error. However, as this applied to both groups this should not affect the results of the study. Another limitation of this study could result from its retrospective design. On the other hand this study is based on a relatively high number of patients, compared to other reports on the treatment of fractures of the edentulous mandible. Furthermore, possible confounders were assessed that might explain postoperative complications.
Notwithstanding these limitations, the results of this study show that following the compiled treatment protocol for fractures of edentulous mandibles significantly reduces postoperative complications and reoperations.
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