Abstract
Objectives:
Pseudarthrosis after mandibular reconstruction leads to chronic overload of the osteosynthesis and impedes dental rehabilitation. This study evaluates the impact of gap site on osseous union in mandible reconstruction using a new volumetric analysis method with repeated cone-beam computed tomography (CBCT).
Methods:
The degree of bone regeneration was evaluated in 16 patients after mandible reconstruction with a fibula free flap and patient-specific reconstruction plates. Percentual bone volume and width changes in intersegmental gaps were retrospectively analyzed using a baseline CBCT in comparison to a follow-up CBCT. Patients’ characteristics, plate-related complications, and gap sites (anterior/posterior) were analyzed. Detailed assessments of both gap sites (buccal/lingual/superior/inferior) were additionally performed.
Results:
Intersegmental gap width (p = 0.002) and site (p < 0.001) significantly influence bone volume change over two consecutive CBCTs. An initial larger gap width resulted in a lower bone volume change. In addition, anterior gaps showed significantly less bone volume changes. Initial gap width was larger at posterior segmental gaps (2.97 vs 1.65 mm, p = 0.017).
Conclusions:
A methodology framework has been developed that allows to quantify pseuarthrosis in reconstructed mandibles using CBCT imaging. The study identifies the anterior segmental gap as a further risk factor for pseudarthrosis in reconstructions with CAD/CAM reconstruction plates. Future research should evaluate whether this outcome is related to the biomechanics induced at this site.
Keywords: Mandibular reconstruction, Pseudarthrosis, Cone-Beam Computed Tomography, Fibula, Surgical Flaps
Introduction
Malignancies, osteonecrosis of the jaw and trauma are the main reasons for mandibular reconstruction with free flaps. Most commonly a fibula free flap is used to achieve good aesthetic and functional results. 1 Despite several innovations concerning material improvements and techniques over the past decades, 1,2 overall complication rates after microvascular free flap reconstruction are still at a high rate of around 40%. 3 Complications include wound healing disorders, plate exposure, fixation failure, and most commonly incomplete osseous union. 1
Pseudarthrosis in patients with mandibular reconstruction leads to chronic overload of the fixation plate and screws with increased risk of fixation failure and plate exposure. 4 Furthermore, it impedes dental rehabilitation with implants and prosthetics. 4 Reducing the incidence of pseudarthrosis is a crucial factor concerning a reduction of the overall complication rate.
In mandibular reconstruction, adjuvant radiotherapy and multisegmental flap designs are known as independent risk factors for pseudarthrosis. 1 Recently, the gap width between mandible and fibula segments has been identified as a further risk factor. 5 Distances between osseous segments higher than 2.55 mm have been associated with a higher risk of non-union. 5
From long bones it is known that the biomechanics at the healing site influence bone healing significantly. 6 In biomechanical studies of the mandible, differences in segmental gap movements between different gap sites were found. 7,8 However, no study has yet examined the influence of the gap site on the development of pseudarthrosis in mandibular reconstruction clinically.
Due to the two-dimensionality of the panoramic view and due to artefacts in computer tomography, radiological detection of pseudarthrosis is challenging (Figure 1). 9 Involvement of three-dimensional imagery like cone-beam computed tomography (CBCT) enhances the image quality. 10,11
Figure 1.
Artefact disturbance in CT imagery complicate the detection of pseudarthrosis approximately three months after mandibular reconstruction using a fibula free flap (A = bone window, B = soft tissue window, *=Fibula bone).
The aim of this study is to quantify bone regeneration within intersegmental gaps after mandible reconstruction. We hypothesize that the gap site in mandible reconstruction is an independent risk factor for pseudarthrosis. We also presume that repetitive CBCT image analyses over time enable a quantitative evaluation of the intersegmental gap in order to address this question.
Methods
Patient inclusion criteria and study design
This retrospective study was approved by the Ethics Committee of the medical faculty of Charité – Universitätsmedizin Berlin (EA2/138/18). All patients who underwent mandibular reconstruction with a fibula free flap and a patient-specific titanium reconstruction plate (2.0 mm, Gebrüder Martin GmbH & Co. KG, Tuttlingen, Germany) at the Department of Oral and Maxillofacial Surgery of Charité – Universitätsmedizin Berlin between August 2017 and July 2021 were included in the initial screening process. Preoperative imagery of the mandible area either included a CBCT or CT. Only patients who underwent a digital CBCT less than eight weeks after surgery (baseline) and a second CBCT at least 2 months later (follow-up) met the inclusion criteria. Further inclusion criteria included the concurrent presence of one anterior (paramedian/canine region of mandible) and one posterior osteotomy gap (mandibular angle) between the fibula and the mandible (L-type or LC-type according to Boyd`s classification). 12 Exclusion criteria were major postoperative complications (flap revision or material failure) that could have impaired the healing process and operative procedures in the region of analysis (reosteosynthesis, surgical remodeling of the bone or plate removal) between initial surgery and follow-up CBCT.
All CBCT scans were performed with the same device (MedSeries H23, Sophisticated Computertomographic Solutions GmbH, Aschaffenburg, Germany) and same adjustments (isotropic voxel edge length of 0.4 mm in all directions). There was no specific artefact reduction adjustment.
Determination of gap volume and width
DICOM files of CBCT scans were imported into the image processing software ImageJ (ImageJ for Java 8, version 1.53f, National Institute of Health, Bethesda, Maryland, USA). Volume and gap width analyses were performed exclusively for the anterior and posterior intersegmental gap between fibula and the native mandible (Figure 2).
Figure 2.
Sequence of analysis: After identifying a baseline and follow-up CBCT, DICOM files were imported to the image processing software. Volumetric analysis was performed for the posterior and anterior gap. Each intersegmental gap was divided into subsections (buccal, lingual, superior, inferior). Only volume change in between cortical bone was analyzed. Figure created with Biorender.com.
Interactive stack rotation was used to show the osteotomy gap in its entirety from a caudal perspective. Only slices with possible differentiation of buccal and lingual cortex were analyzed. The areas in between both the lingual and buccal cortex of the fibula and mandible were determined manually every three slices using the tool “freehand selection” by two individual observers. The remaining gaps in between the manually determined gaps were interpolated by software (Figure 3). The area in between the cancellous bone areas was not used to determine volume changes due to the limited accuracy in differentiation between cancellous bone and the segmental gap. The quality and feasibility of interpolation were checked during establishment of the methodology. By adding all slices together, the total volume (TV [mm3]) for different areas (lingual, buccal, inferior, superior) of the intersegmental gap could be obtained. The TV for the complete osteotomy gap was obtained using the sum of the TV of the lingual and buccal cortex. Changes in TV between the baseline and follow-up CBCTs were analyzed by calculating the percentage change. Complete osseous union (100% union) was indicated as 100 % volume change, non-union as 0 % volume change. Partial unions were indicated with a value between 0 and 100%.
Figure 3.
Visualization of determination of gap area (exemplary lingual gap area). Both, the buccal and lingual gap areas between fibula bone and mandible were examined. Every third CBCT slice was defined by the examiner, other slices were interpolated by the software. Gap width was also analyzed at four different anatomical regions of the gap (buccal, lingual, superior and inferior). Figure created with Biorender.com.
For a more distinct analysis of the healing process within anterior and posterior gaps, separate analyses of exclusively inferior versus superior and buccal versus lingual parts were also performed.
In addition, the initial intersegmental gap width (mm) was measured in between both the buccal and lingual cortex, as well as between the inferior and superior point of the fibula and native mandible in the central slice of the baseline CBCT. Mean values of gap widths between buccal and lingual cortex were calculated for each segmental gap to further analyze the impact of gap width as a known confounding variable.
Statistical analysis
The collected data were compiled in a database (Microsoft Excel, Microsoft Corporation, Redmond, USA). Descriptive analysis was used to calculate the mean percentage changes in volume. Differences concerning volume change and gap width between segmental gaps were analyzed using unpaired t-tests for normally distributed data. Linear regression was used for identification of risk factors (independent variables) on volume change (dependent variable). The level of significance was set at 5% (p = 0.05) for all analyses. All analyses were performed using SPSS (version 27.0.0., IBM Corp., Armonk, New York, USA).
Results
Inclusion criteria were met in 16 patients. There were eleven male and five female patients included (Table 1). The average time between surgery and baseline CBCT was 16.6 ± 16.0 (range 4–37) days and the time between baseline and follow-up CBCT was 51.7 ± 21.5 (range 17.7–153.4) weeks. Further characteristics such as indication for surgery, number of segments, radio/chemotherapy, diabetes, vascular disease, smoking, wound healing disorder/fistula, plate exposure, and material failure are reported in Table 1. All complications (wound healing disorder/fistula, plate exposure, material failure) were only detected at the region of the anterior gap.
Table 1.
Patient characteristics
| Variable | Category | Mean (±SD) /frequency (%) |
|---|---|---|
| Gender | Female | 5 (31.2%) |
| Male | 11 (68.8%) | |
| Age at surgery | 64.0 (±10.10) | |
| Interval between surgery and baseline CBCT (days) | 16.6 (±16.0) | |
| Interval between baseline and follow-up CBCT (weeks) | 51.7 (± 21.5) | |
| Indication for surgery | Squamous cell carcinoma | 8 (50.0%) |
| Ameloblastoma | 1 (6.2%) | |
| Osteoradionecrosis | 5 (31.3%) | |
| MRONJ | 1 (6.2%) | |
| Osteomyelitis | 1 (6.2%) | |
| Number of segments | 1 | 6 (37.5%) |
| 2 | 8 (50.0%) | |
| 3 | 2 (12.5%) | |
| Adjuvant radiotherapy | Yes | 5 (31.2%) |
| No | 11 (68.8%) | |
| Adjuvant chemotherapy | Yes | 0 |
| No | 16 (100%) | |
| Diabetes | Yes | 1 (6.2%) |
| No | 15 (93.8%) | |
| Vascular disease | Yes | 3 (18.8%) |
| No | 13 (81.2%) | |
| Smoking | Yes | 6 (37.5%) |
| No | 10 (62.5%) | |
| Wound healing disorder/Fistula | Yes | 4 (25.0%) |
| No | 12 (75.0%) | |
| Plate exposure | Yes | 3 (18.8%) |
| No | 13 (81.2%) | |
| Material failure (plate fracture) | Yes | 1 (6.2%) |
| No | 15 (93.8%) |
CBCT = cone beam computed tomography;MRONJ = medication-related osteonecrosis of the jaw.
In each patient both the anterior and posterior gaps between fibula and mandible were analyzed, resulting in a total of 32 intersegmental gaps. The number of examined slices was dependent on osseous union and height of the fibula bone. On average, 16 slices were analyzed for each gap. Average volume changes as an indicator for ossification, were higher for the posterior gap (74.12%±30.21) compared to the anterior gap (50.86%±39.46). The level of significance was not reached for this comparison (p = 0.071) in the univariate analysis. The average initial gap width was significantly higher in the posterior gap compared to the anterior gap (posterior: 1.65 mm±1.20, anterior: 2.97 mm±1.71; p = 0.017). A univariate linear regression analysis was used for a descriptive analysis of the impact of each variable on volume change (Table 2).
Table 2.
Univariate linear regression analysis
| Variable | Category | Mean volume change (%) (±SD) | p-Value, B |
|---|---|---|---|
| Initial gap width | 0.249,–4.780 | ||
| Gap site | Anterior Posterior |
50.86 (±39.46) 74.12 (±30.21) |
0.071,–23.26 |
| Gender | Female | 65.35 (±32.99) | 0.737, 4.583 |
| Male | 60.77 (±39.23) | ||
| Age at surgery | 0.633,–0.311 | ||
| Interval between CBCT scans | 0.024, 1.853 | ||
| Indication for surgery | SCC | 61.48 (±37.69) | 0.602,–2.716 |
| Ameloblastoma | 90.08 (±6.02) | ||
| Osteoradionecrosis | 61.92 (±38.26) | ||
| MRONJ | 87.76 (±17.30) | ||
| Osteomyelitis | 20.58 (±14.53) | ||
| Number of segments | 1 | 75.74 (±29.15) | 0.282,–10.657 |
| 2 | 51.94 (±38.01) | ||
| 3 | 64.94 (±46.32) | ||
| Adjuvant radiotherapy | Yes | 68.90 (±34.72) | 0.144,–20.511 |
| No | 48.39 (±38.24) | ||
| Diabetes | Yes | 36.59 (±42.81) | 0.308,–27.624 |
| No | 64.22 (±36.25) | ||
| Vascular disease | Yes | 29.62 (±29.40) | 0.012,–40.454 |
| No | 70.07 (±34.10) | ||
| Smoking | Yes | 44.78 (±37.87) | 0.031,–28.339 |
| No | 73.12 (±32.09) | ||
| Wound healing disorder/fistula | Yes | 68.67 (±39.22) | 0.589, 8.245 |
| No | 60.43 (±36.23) | ||
| Plate exposure | Yes | 61.22 (±45.15) | 0.951,–1.399 |
| No | 62.62 (±36.49) | ||
| Material failure (plate fracture) | Yes | 57.39 (±60.26) | 0.842,–5.441 |
| No | 62.83 (±36.05) |
B = regression coefficient; CBCT = cone-beam computed tomography;MRONJ = medication-related osteonecrosis of the jaw; SCC = squamous cell carcinoma.
A multiple linear regression model was consequently used to adjust for all variables as confounders (Table 3, Figure 4). This model allows the analysis of different confounding factors on volume change simultaneously. In this model, gap site (anterior vs posterior) (p < 0.001) as well as the initial gap width (p = 0,002) were statistically significant influences on volume changes. Of all patient characteristics, only the indication for surgery had a significant influence on volume change (p = 0.034), which was mainly influenced by small volume change in a patient with osteomyelitis (Table 2).
Table 3.
Regression analysis of all variables with volume change as the dependent variable
| Variable | p-Value | 95% CI |
|---|---|---|
| Initial gap width | 0.002 | -24.9,–7.0 |
| Gap site | <0.001 | -73.0,–26.0 |
| Gender | 0.822 | −45.9, 36.9 |
| Age at surgery | 0.242 | −0.6, 2.3 |
| Interval between CBCT scans | 0.506 | −1.2, 2.4 |
| Indication for surgery | 0.034 | -25.7,–1.2 |
| Number of segments | 0.326 | −58.2, 20.5 |
| Adjuvant radiotherapy | 0.069 | −70.1, 2.9 |
| Diabetes | 0.659 | −47.6, 73.4 |
| Vascular disease | 0.782 | −70.4, 53.9 |
| Smoking | 0.259 | −54.5, 15.7 |
| Wound healing disorder/fistula | 0.910 | −57.5, 64.2 |
| Plate exposure | 0.170 | −12.8, 66.8 |
| Material failure | 0.908 | −79.0, 88.2 |
CBCT = cone-beam computed tomography.
Figure 4.
Visual demonstration of regression analysis of volume change and gap width with separation of gap site (blue: posterior gap, red: anterior gap). Required assumptions for linear regression were met.
In the additional analysis of inferior versus superior and buccal versus lingual parts within each segmental gap there were no significant differences concerning mean volume changes (Table 4). The initial gap width was significantly larger in the posterior lingual compared to the posterior buccal gap (p = 0.001). The multiple linear regression model including gap site and initial gap width as independent variables only showed a statistically significant influence of the initial gap width (buccal/lingual) on the volume change in the posterior gap (p = 0.025) (Table 4).
Table 4.
Mean gap widths and volume changes of different gap sites. Additional linear regression analysis including gap width and gap site as independent variables on volume change (dependent variable).
| Gap site | Mean initial gap width (mm) (±SD) |
Mean volume change (%) (±SD) |
Variable gap width in regression analysis with gap site (p; 95% CI) | Variable gap site in regression analysis with gap width (p; 95% CI) | |
|---|---|---|---|---|---|
| Anterior | Total | 1.65 (±1.20) | 50.86 (±39.46) | ||
| Posterior | Total | 2.97 (±1.71) | 74.12 (±30.21) | ||
| t-test | 0.017 | 0.071 | |||
| Anterior | Inferior | 0.75 (±0.32) | 55.18 (±44.00) | ||
| superior | 1.26 (±1.35) | 46.87 (±37.93) | |||
| t-test | 0.153 | 0.571 | 0.781 (−18.09, 13.72) |
0.641 (−24.02, 38.42) |
|
| Buccal | 1.48 (±1.75) | 38.99 (±41.40) | |||
| Lingual | 1.82 (±1.21) | 49.49 (±44.07) | |||
| t-test | 0.528 | 0.492 | 0.389 (−15.23, 6.11) |
0.437 (−19.20, 43.29) |
|
| Posterior | Inferior | 1.22 (±1.27) | 76.31 (±35.12) | ||
| Superior | 1.29 (±0.61) | 68.84 (±32.24) | |||
| t-test | 0.844 | 0.536 | 0.839 (−14.11, 11.54) |
0.548 (−17.43, 32.18) |
|
| Buccal | 1.63 (±1.25) | 74.54 (±34.77) | |||
| Lingual | 4.33 (±2.52) | 73.80 (±31.86) | |||
| t-test | 0.001 | 0.950 |
0.025
(-12.58,–0.90) |
0.203 (−9.99, 44.92) |
|
Discussion
This study aimed to evaluate if pseudarthrosis after mandibular reconstruction is dependent on initial intersegmental gap size and the gap site. Repetitive CBCT image analysis over time was used to quantitatively evaluate bone regeneration of the intersegmental gaps in patients after mandible reconstruction. We show that large initial gap width and the anterior gap site are risk factors for non-union.
There are different ways to assess bone healing in general. In mandibular reconstruction, all previous studies have performed a qualitative assessment using a panoramic view, CT, or CBCT. 1,5,9,13,14 Due to the limitations of qualitative assessments, also quantitative evaluations have been described as an alternative evaluation method. However, this has only been performed in secondary bone grafting assessments in cleft patients. 15–17
For the evaluation of pseudarthroses in mandibular reconstruction, both methods have weaknesses though. Besides the limited value of qualitative assessments, detection of pseudarthrosis using two-dimensional imagery is unfavorable due to the overlay of fixation plates. In contrast to panoramic views, CBCT scans allow a complete display of the intersegmental gaps. However, intersegmental gaps are in direct proximity to fixation plates, which are usually made of titanium. 1 Titanium plates induce significant artefacts in postoperative imaging and thus impede assessments severely. 18 For this reason, quantitative analyses as described in cleft patients are not completely transferrable to mandibular reconstruction. This indicates the need for strategies for artefact reduction to reliably identify pseudarthrosis in mandibular reconstruction.
In this study, we present a possible solution to reliably evaluate the existence of radiological pseudarthrosis and measure intersegmental gap widths by comparing repeated CBCT scans at different points in time after surgery quantitatively with volumetric analysis. This strengthens the quality in comparison to previously performed qualitative analyses of pseudarthrosis in other studies. 1,5,9,13,14 Furthermore, the degree of objectivity of these assessments is much higher.
The presented methodology was used to analyze the impact of the initial gap width on volume change (indicating pseudarthrosis) and differences in gap widths between gap sites. A previous study by Hashemi et al indicated the relevance of the initial gap width on the development of pseudarthrosis in mandibular reconstruction. 5 Their findings of a general influence of gap width on development of pseudarthrosis were confirmed by this study (Table 3). A negative correlation between gap width and volume change was found, indicating higher rates of pseudarthrosis in cases of initially larger gap widths (Figure 4).
This strengthens the need for well-performed mandibular reconstructions with minimization of initial intersegmental gap sizes. Especially in complex reconstructions this can be challenging, even in high-volume centers. Precise osteotomy with CAD/CAM drilling and cutting guides can help to obtain close segment proximity, however, just minimal deviations during osteotomy, even with cutting guides, can result in increased gap widths and thus negatively impact bone healing. Piezosugery revealed advanced bone healing in comparison to conventional saw blades, 19 but osteotomies have been performed using piezosurgery at the fibula and conventional saw blades at the mandible in our center.
Increased accuracy in mandibular reconstruction with patient-specific CAD/CAM plates has recently been described. 20 However, in the current study, gap widths were not always as small as expected (Table 4).
Variations of gap widths were not only detected between different patients, but also in reconstruction sites within the same patient. The present study revealed significantly larger gap widths in posterior gaps located at the mandible angle compared to anterior gaps located in the paramedian region of the mandible. This may be due to the fact, that positioning and fixation of cutting guides as well as correct angulation during osteotomy with a piezotome or bone saw is sometimes more challenging in the angle and ramus region with disruptive tissue, namely the cranial platysma-skin flap, sternocleidomastoid, and masseter muscle and parotid gland pushing and pulling against the surgical instruments during osteotomy. This may result in a false angulation and thus increased gap width.
Remarkably, while there was a significant difference in the initial gap width (posterior>anterior), no significant differences between the gap sites were found for mean volume changes (Table 4). Considering, that increased gap width is known to be associated with pseudarthrosis, one would have assumed worse outcomes of the posterior gap as a result. In contrast, a converse trend towards lower rates of pseudarthrosis at the posterior gap was found (Figure 4) and confirmed by multiple linear regression (Table 3). The results indicate significantly lower rates of pseudarthrosis at the posterior compared to the anterior gap. The difference between univariate and multiple linear regression also illustrates that for a reliable interpretation of volumetric analyses, the simultaneous determination of gap width is compulsory. Both, larger gap widths at the posterior intersegmental gap and diminished osseous union at the anterior gap have not been described before. This study therefore introduces a new risk factor for pseudarthrosis in mandibular reconstruction - the anterior segmental gap.
Two potential factors may explain the trend towards better healing outcomes in the posterior gap (angle region). The importance of soft tissue coverage of osteosynthesis to reduce complications has recently been reported. 21 In contrast to the paramedian region, soft tissue closure in the angle region is usually easier with residual masseter and medial pterygoid muscle attachments. In the anterior region sufficient soft tissue coverage might be difficult if no bulky skin is used for intraoral reconstruction. This is further undermined by a recent study of our group reporting increased plate exposure rates at the paramedian region in comparison to the ramus and angle region. 1 Also in the current study, primary wound healing disorders, fistula, and late-onset plate exposures were only registered in the paramedian region. Although there were five patients receiving adjuvant radiotherapy with a radiation field in the anterior region, radiotherapy had no influence on volume change.
Secondly, differences in bone healing between the anterior and posterior gap may be explained by the biomechanics of mandible reconstruction. For bone healing, axial loading conditions are beneficial while shear stress is associated with delayed healing and potentially non-union. 6,22–24 The intensity of axial loads may differ between gap sites. In our department, the standard angulation between the fibula and mandible segment is between 30° and 45°, whereas the anterior gap has a vertical orientation. This may result in higher axial loads at the posterior gap with a beneficial effect on bone healing, however this remains to be further investigated.
Load directions in mandibular reconstruction are highly complex due to muscle forces during mastication and geometrical complexity. These forces result in a compression zone at the inferior border and a tension zone at the superior mandible border. 25 Interestingly, despite theoretically increased axial compression forces at inferior borders, this study could not reveal lower rates of pseudarthrosis at inferior borders for both the anterior and posterior gap (Table 4). Higher rates of pseudarthrosis at the anterior gap might therefore not only be caused by the impact of load directions. This is underlined by previous biomechanical studies analyzing intersegmental gap movements, which could not reveal significant differences between anterior and posterior gaps. However, load directions were not analyzed in particular in these studies. 8,26,27 Finite element analyses including a precise simulation of (residual) muscle activation after surgery and the potential impact of osteotomy angulation and different plate fixation techniques on the stresses and strains are therefore necessary in future studies.
The relatively small number of patients can be regarded as a limitation of the study. The significant impact of the indication for surgery on volume change might have been a consequence of this. The relatively small case number was rooted in the fact that CBCT scans at two different points in time were available only for these patients. This problem is based on our in-house standard, where every patient receives a CBCT scan within the initial stage after surgery but routine tumor staging includes a conventional CT scan in the postoperative course. There is no conventional CT scan immediately after surgery available. Since osseous union is often assessed along the way with CT scans, further CBCT scans are often not necessary. A specific determination of pseudarthrosis using CBCT instead of CT would reduce radiation doses 28 and allow a quantitative analysis of osseous union. Magnetic resonance imaging (MRI) could replace CT scans for postoperative tumor staging, which was overall more accurate for tumor staging. 29
Further limitations include variations in intervals between CBCT imagery. Also, artefacts are still a confounding factor, although the impact of artefacts is diminished due to the analysis of CBCTs at different points in time and all patients having received reconstruction plates. Analyses are time-consuming so clinical use is more realistic in selected patients due to reasons of practicability. For dental rehabilitation after mandible reconstruction, plate removal and therefore complete osseous union is often necessary. 4 In cases of difficult evaluations of osseous unions before dental implantation, the methodology developed here could therefore be helpful. The presented methodology could also be transferred to other parts of oral and maxillofacial surgery such as orthognathic surgery or fracture treatment, where interferences with artefacts are a major issue.
Conclusion
Quantitative evaluation of intersegmental gaps in mandibular reconstruction using repetitive CBCT image analysis is a reliable and objective assessment of pseudarthrosis.
The relevance of the initial gap width on the development of pseudarthrosis was confirmed. Furthermore, the anterior gap site was identified as a new risk factor for non-union after osteosynthesis with patient-specific reconstruction plates. Determination of the initial gap width is compulsory when analyzing other influencing factors on the osseous union. Further research including finite element analyses are needed to identify reasons for differences in bone healing between gap sites.
Contributor Information
Claudius Steffen, Email: claudius.steffen@charite.de.
Heilwig Fischer, Email: heilwig.fischer@charite.de.
Marius Sauerbrey, Email: marius.sauerbrey@charite.de.
Thelma Heintzelmann, Email: thelma-theresa.heintzelmann@charite.de.
Jan Oliver Voss, Email: jan.voss@charite.de.
Steffen Koerdt, Email: steffen.koerdt@charite.de.
Sara Checa, Email: sara.checa@bih-charite.de.
Kilian Kreutzer, Email: kilian.kreutzer@charite.de.
Max Heiland, Email: max.heiland@charite.de.
Carsten Rendenbach, Email: carsten.rendenbach@charite.de.
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