Major mandibular surgical procedures as an indication for intraoperative imaging

Use of intraoperative 3D imaging in the maxillofacial operating room: A French national survey

PURPOSE

To gain a comprehensive understanding of the utilization of intraoperative 3D imaging among maxillofacial surgeons practicing in France through a web-based questionnaire.

METHODS

An 18-point multiple-choice questionnaire was developed and distributed to participants. The questionnaire was divided into two sections, with the first section gathering general information about the respondents and the second section providing an overview of the utilization of 3D imaging techniques, such as cone-beam computed tomography (CBCT), computed tomography (CT) scan, and magnetic resonance imaging (MRI), including the conditions, frequencies, and indications for use, with a particular focus on the number of acquisitions per procedure and the other departments with whom the equipment is shared.

RESULTS

A total of 75 participants completed the survey, with 30% of university hospital departments and 0% of private clinics currently utilizing intraoperative 3D imaging systems. The main indications for 50% of the users were for temporomandibular joint surgery and orbital fractures.

CONCLUSION

The results of this survey indicate that the utilization of intraoperative 3D imaging in French maxillofacial surgery is limited to university centers, with poor utilization and a lack of standardization in indications for use.

On the use of intraoperative 3D-RX C-arm imaging in orthognathic surgery: a prospective non-consecutive case series study

CONTEXT

Segment and osteosynthesis malposition resulting in patients' complaints (mainly about asymmetries) are encountered in orthofacial/orthognathic surgery.

OBJECTIVE, DESIGN, AND SETTING

We planned to investigate the usefulness of intraoperative three-dimensional (3D) imaging concerning positioning and fixation of bone segments and osteosynthesis in orthognathic/orthofacial surgery. We performed a prospective study of non-consecutive cases. All patients receiving a bimaxillary osteotomy, genioplasty, and their combinations were included in the study from May 2016 to May 2020. Unilateral and bilateral sagittal split osteotomies were excluded. There were no gender and age limitations. All were intraoperatively examined using the BV Pulsera 3D-RX System (Philips Medical, Eindhoven, The Netherlands). The outcome variables were the percentage of revisions of segment positioning and osteosynthesis. Predictor variables were age, gender, type of surgery, timing (pre- and post-imaging), and surgeon experience (senior vs assistant).

RESULTS

Forty female and twenty-two male patients were included (mean age 25.25 years ± 7.52 and 29.1 years ± 12.6 respectively). We evaluated 27 genioplasties and 34 Le Fort "type-I" osteotomies. Indications for segment repositioning and redo-osteosynthesis increased after intraoperative imaging as compared to operator's clinical judgment before intraoperative imaging (95% confidence interval; p < .001 and p = .002 respectively).

CONCLUSION

Suboptimal positioning and fixation of bone segments or osteosynthesis were more apparent with 3D imaging. In addition, some satisfactory cases were also revised for an optimal outcome. As a result, surgeons were prompted to more revisions than judged necessary without intraoperative imaging.

Evaluation of Open Reduction and Internal Fixation of Mandibular Condyle Fracture by Intraoperative Cone-Beam Computed Tomography in a Hybrid Operating Room

Condylar fractures are the most common fractures of the mandible, and treatment of mandibular condylar fractures by maxillofacial surgeons is a very important procedure. However, the surgical approaches have anatomical limitations. Therefore, it is difficult to evaluate the reduction achieved in open reduction and internal fixation because of the uncertainty in securing a sufficient operative field. As a potential solution, the authors evaluated the benefits of intraoperative cone-beam computed tomography (CBCT) with high image quality performed in a hybrid operating room. Intraoperative CBCT is easy to perform in a hybrid operating room, and it is possible to quickly evaluate high-quality CT images, including 3D images. Because the state of reduction of mandibular condylar fractures also affects the prognosis of treatment, more precise reduction and fixation should improve prognoses. The use of CBCT in a hybrid operating room also avoids re-operation, and patients benefit from minimum invasive surgery. Intraoperative CBCT is a very useful strategy for evaluation of mandibular condylar fracture surgical treatment.

How useful is intraoperative cone beam computed tomography in maxillofacial surgery? An overview of the current literature

Intraoperative imaging is increasingly used by surgeons and has become an integral part of many surgical procedures. This study was performed to provide an overview of the current literature on the intraoperative use of cone beam computed tomography (CBCT) imaging in maxillofacial surgery. A bibliographic search of PubMed was conducted in March 2020, without time limitation, using "intraoperative imaging" AND "maxillofacial surgery" AND "cone beam computed tomography" as key words. Ninety-one articles were found; after complete reading, 16 articles met the eligibility criteria and were analysed. The results showed that the majority of the indications were related to maxillofacial trauma, particularly zygomaticomaxillary complex fractures. Final verification with intraoperative CBCT before wound closure was the most common use of this device. However, innovative uses of intraoperative CBCT are expanding, such as CBCT coupling with mirror computational planning, and even the combined use of initial intraoperative CBCT acquisition with navigation. Immediate, fast, and easy evaluation of bone repositioning to avoid the need for further surgical revision is the main advantage of this technique. Imaging quality is comparable to that of multi-slice computed tomography, but with lower radiation exposure. Nevertheless, CBCT is still not widely available in maxillofacial centres, probably because of its cost, and perhaps because not everyone is aware of its advantages and versatility, which are reported in this review.

The Quality of Life of Patients with Surgically Treated Mandibular Fractures and the Relationship of the Posttraumatic Pain and Trismus with the Postoperative Complications: A Prospective Study

Background and objectives: Due to the fact that the mandible is the only movable bone in the face, it is often exposed to the influence of external forces. The incidence of trismus and posttraumatic pain in unilateral mandibular corpus fractures may be related to the occurrence of complications. There is a decrease in the quality of life of these patients. The aim was to study the relationship of the preoperative pain and trismus with the incidence of complications, as well as to investigate the quality of life. Materials and Methods: A prospective study on 60 patients with isolated mandibular fractures was performed, with a follow-up period of six months. The level of preoperative pain was measured on a 0–10 scale, while the mouth opening was measured with a caliper. All patients were treated surgically on the third day after the fracture. The University of Washington Quality of Life (UW-QOL v4) questionnaire was used to analyze the quality of life. Results: The most common types of complications were the occlusal derangement and facial asymmetry. The majority of complications were treated with counseling and physical therapy. The degree of preoperative pain was significantly positively related to the onset of complications (r_s = 0.782, p = 0.004). The interincisal distance showed a significant inverse relation with the incidence of complications (r_s = −0.722, p < 0.001). The patients regarded the pain, appearance and mood issues as the most important issues during the first postoperative month. Conclusions: The degree of inflammatory symptoms may be positively related to the onset of complications occurring after the rigid fixation of mandibular fractures. The postoperative health-related and overall quality of life was unsatisfactory in nearly half of the patients.

Cone beam computed tomography: basics and applications in dentistry

The introduction of cone beam computed tomography (CBCT) devices, changed the way oral and maxillofacial radiology is practiced. CBCT was embraced into the dental settings very rapidly due to its compact size, low cost, low ionizing radiation exposure when compared to medical computed tomography. Alike medical CT, 3 dimensional evaluation of the maxillofacial region with minimal distortion is offered by the CBCT. This article provides an overview of basics of CBCT technology and reviews the specific application of CBCT technology to oral and maxillofacial region with few illustrations.

Tomographic Evaluation of Mandibular Thickness on Premolar and Molar Regions Related to Monocortical Screws

The aim of this study was to measure the thickness of the mandible from the external cortical plate to the teeth roots on premolar and molar regions using CT scan to determine the safety margin for the application of monocortical screws for internal rigid fixation. Thirty-one patients underwent CT-scan imaging for surgical planning. The images were used to measure bilaterally the distance from the external cortex of the mandible to the roots of teeth on premolar and molar region by means of Dental Slice software (Bioparts Prototipagem Biomedica, Brasília, DF, Brazil). Mean, median, standard deviation, one-way ANOVA and post hoc Tukey's test were used for statistical analysis. No statistical differences for thickness were found between right and left side (p = 0.1652). The mean thickness for the left side was 4.17 ± 1.68 mm and for right side 3.93 ± 1.49 mm. Increase in mandibular thickness from anterior to posterior regions in both sides was observed and statistical difference was found among the different groups according to the measured region (p < 0.05). The present results can predict the safety zone for the use of monocortical screws in the mandible, but the use of CT scan is imperative and individual analysis is desired owing to anatomical variations. Further studies with larger samples are necessary to confirm these data and should include other anatomic structures, different regions of mandible/maxilla, as well as other ethnic groups.

Accurate Evaluation of Cone-Beam Computed Tomography to Volumetrically Assess Bone Grafting in Alveolar Cleft Patients

OBJECTIVE

The aim of this study was to investigate the accuracy of cone-beam computed tomography (CBCT) to assess the volume of bone graft in alveolar cleft patients.

MATERIALS AND METHODS

Twelve patients of unilateral alveolar cleft were included in this study. All patients were taken CBCT preoperative and 1 week postoperative. The digital imaging and communications in medicine (DICOM) files were imported into Simplant software and three-dimensional (3D) reconstruction of the alveolar defect was achieved. With 3D volumetric measurements module, the volume of alveolar cleft was calculated preoperatively. During operation, the syringe compression method was adopted to calculate the actual amount of bone graft. One week postoperative, CBCT scan was performed again to measure the bone volume grafted to the defect. The volumetric ratio of the syringe compression method to preoperative CBCT assessment and the volume difference between syringe compression method and postoperative CBCT assessment were analyzed to evaluate the accuracy of CBCT measurement.

RESULTS

The 3D structure of the alveolar cleft and the boundary of bone graft was clear from CBCT images. The estimated volume of alveolar cleft by preoperative CBCT scans was 1.06 ± 0.09 cm, and the actual amount of bone graft determined by the syringe compression method was 1.51 ± 0.12 cm. The ratio between the latter to the former was 1.43 ± 0.07. The calculated volume of bone graft by 1-week postoperative CBCT scans was 1.53 ± 0.11 cm, with no significant difference compared with the actual amount of bone graft (P > 0.05).

CONCLUSIONS

CBCT was an accurate measurement to calculate the volume of alveolar defect and bone graft in alveolar cleft patients. Preoperative scans could aid in quantitatively determining the bone amount needed to adequately fill the bone defect, and the postoperative scans give accurate follow-up evaluation after surgery.

3D Rapid Prototyping for Otolaryngology-Head and Neck Surgery: Applications in Image-Guidance, Surgical Simulation and Patient-Specific Modeling

The aim of this study was to demonstrate the role of advanced fabrication technology across a broad spectrum of head and neck surgical procedures, including applications in endoscopic sinus surgery, skull base surgery, and maxillofacial reconstruction. The initial case studies demonstrated three applications of rapid prototyping technology are in head and neck surgery: i) a mono-material paranasal sinus phantom for endoscopy training ii) a multi-material skull base simulator and iii) 3D patient-specific mandible templates. Digital processing of these phantoms is based on real patient or cadaveric 3D images such as CT or MRI data. Three endoscopic sinus surgeons examined the realism of the endoscopist training phantom. One experienced endoscopic skull base surgeon conducted advanced sinus procedures on the high-fidelity multi-material skull base simulator. Ten patients participated in a prospective clinical study examining patient-specific modeling for mandibular reconstructive surgery. Qualitative feedback to assess the realism of the endoscopy training phantom and high-fidelity multi-material phantom was acquired. Conformance comparisons using assessments from the blinded reconstructive surgeons measured the geometric performance between intra-operative and pre-operative reconstruction mandible plates. Both the endoscopy training phantom and the high-fidelity multi-material phantom received positive feedback on the realistic structure of the phantom models. Results suggested further improvement on the soft tissue structure of the phantom models is necessary. In the patient-specific mandible template study, the pre-operative plates were judged by two blinded surgeons as providing optimal conformance in 7 out of 10 cases. No statistical differences were found in plate fabrication time and conformance, with pre-operative plating providing the advantage of reducing time spent in the operation room. The applicability of common model design and fabrication techniques across a variety of otolaryngological sub-specialties suggests an emerging role for rapid prototyping technology in surgical education, procedure simulation, and clinical practice.

Diagnostic efficacy of cone-beam computed tomography for mandibular fractures

OBJECTIVE

The aim of the study was to determine the clinical efficacy of maxillofacial cone-beam computed tomography (CBCT) for the diagnosis of suspected mandibular fractures and to evaluate whether findings would lead to a change in treatment.

STUDY DESIGN

CBCT imaging was performed for 164 patients with suspected mandibular fractures (231 sites) but equivocal clinical and radiological findings (conventional radiography). Images were interpreted by oral and maxillofacial surgeons and treatment decisions based on pre and postimaging were compared. Linear regression analyses were performed.

RESULTS

For 63.2% of sites (n = 146) the suspected diagnosis was confirmed by CBCT (P < .0001; R(2) = 0.93). For 4.33% of sites (n = 10) no fracture was identified. Additional fractures were identified in 17.75% (n = 41) and additional infractures in 14.72% (n = 34). The treatment plan was altered for 9.52% of sites (n = 22).

CONCLUSIONS

CBCT imaging of suspected mandibular fractures resulted in a change in the treatment plan in 9.52%.

The effect of computed tomographic scanner parameters and 3-dimensional volume rendering techniques on the accuracy of linear, angular, and volumetric measurements of the mandible

OBJECTIVES

This study investigates the effect of scanning parameters on the accuracy of measurements from three-dimensional (3D), multi-detector computed tomography (MDCT) mandible renderings. A broader range of acceptable parameters can increase the availability of computed tomographic (CT) studies for retrospective analysis.

STUDY DESIGN

Three human mandibles and a phantom object were scanned using 18 combinations of slice thickness, field of view (FOV), and reconstruction algorithm and 3 different threshold-based segmentations. Measurements of 3D computed tomography (3DCT) models and specimens were compared.

RESULTS

Linear and angular measurements were accurate, irrespective of scanner parameters or rendering technique. Volume measurements were accurate with a slice thickness of 1.25 mm, but not 2.5 mm. Surface area measurements were consistently inflated.

CONCLUSIONS

Linear, angular, and volumetric measurements of mandible 3D MDCT models can be confidently obtained from a range of parameters and rendering techniques. Slice thickness is the primary factor affecting volume measurements. These findings should also apply to 3D rendering using cone-beam CT (CBCT).

Association between mandibular posterior alveolar morphology and growth pattern in a Chinese population with normal occlusion

OBJECTIVE

To investigate the relationship between growth patterns and mandibular posterior tooth-alveolar bone complex morphology in a Chinese population with normal occlusion.

METHODS

Forty-five patients with normal occlusion (23 males, 22 females) were included in this study. Among these patients, 20 displayed the vertical growth pattern, and 20 had the horizontal growth pattern, while the remaining patients displayed the average growth pattern. All of the patients underwent dental cone beam computed tomography (CBCT), which included the region of the mandibular posterior teeth and the alveolar. A linear regression analysis and a correlation analysis between the facial height index (FHI) and the alveolar bone morphology were performed.

RESULTS

The inclination of the molars, the thickness of the cortical bone, and the height of the mandibular bone differed significantly between patients with the horizontal growth pattern and those with the vertical growth pattern (P<0.05). Significant positive correlations were found between: the FHI and the inclination of the molars; the FHI and the thickness of the cortical bone; and the FHI and the height of the mandibular bone.

CONCLUSIONS

The mandibular posterior tooth-alveolar bone complex morphology may be affected by growth patterns.

Clinical indication for intraoperative 3D imaging during open reduction of fractures of the mandibular angle

PURPOSE

This retrospective study investigated 3-dimensional (3D) imaging with intraoperative Cone-Beam Computed Tomography (CBCT) in Mandibular Angle Fractures (MAF) treated by open reduction. The aim of this study was to demonstrate the image quality of intraoperative CBCT in this region and the benefit for the patients.

METHODS

83 patients with 86 MAF were included in this study. 8 patients were female and 75 male. Patient age ranged from 11 to 68 years (average age 26.8 years). All patients were examined with the mobile CBCT scanner ARCADIS Orbic 3D (Siemens Medical Solutions, Erlangen, Germany) directly after surgical treatment of the MAF.

RESULTS

As a direct result of intraoperative CBCT four patients (5%) underwent intraoperative revision. The intraoperative acquisition of the data sets was uncomplicated and in all cases it was possible to effectively visualise and assess the MAF in 3D quality.

CONCLUSION

The results showed that intraoperative CBCT is a reliable imaging technique for real-time intraoperative assessment of treated MAF. Use of the mobile 3D CBCT scanner is easy to integrate into routine practice and offers the advantage that immediate revision surgery can be performed.

Segmentation process significantly influences the accuracy of 3D surface models derived from cone beam computed tomography

AIMS

To assess the accuracy of surface models derived from 3D cone beam computed tomography (CBCT) with two different segmentation protocols.

MATERIALS AND METHODS

Seven fresh-frozen cadaver heads were used. There was no conflict of interests in this study. CBCT scans were made of the heads and 3D surface models were created of the mandible using two different segmentation protocols. The one series of 3D models was segmented by a commercial software company, while the other series was done by an experienced 3D clinician. The heads were then macerated following a standard process. A high resolution laser surface scanner was used to make a 3D model of the macerated mandibles, which acted as the reference 3D model or "gold standard". The 3D models generated from the two rendering protocols were compared with the "gold standard" using a point-based rigid registration algorithm to superimpose the three 3D models. The linear difference at 25 anatomic and cephalometric landmarks between the laser surface scan and the 3D models generate from the two rendering protocols was measured repeatedly in two sessions with one week interval.

RESULTS

The agreement between the repeated measurement was excellent (ICC=0.923-1.000). The mean deviation from the gold standard by the 3D models generated from the CS group was 0.330mm±0.427, while the mean deviation from the Clinician's rendering was 0.763mm±0.392. The surface models segmented by both CS and DS protocols tend to be larger than those of the reference models. In the DS group, the biggest mean differences with the LSS models were found at the points ConLatR (CI: 0.83-1.23), ConMedR (CI: -3.16 to 2.25), CoLatL (CI: -0.68 to 2.23), Spine (CI: 1.19-2.28), ConAntL (CI: 0.84-1.69), ConSupR (CI: -1.12 to 1.47) and RetMolR (CI: 0.84-1.80).

CONCLUSION

The Commercially segmented models resembled the reality more closely than the Doctor's segmented models. If 3D models are needed for surgical drilling guides or surgical planning which requires high precision, the additional cost of the commercial segmentation services seem to be justified to produce a more accurate surface models.

An indentation depth-force sensing wheeled probe for abnormality identification during minimally invasive surgery

This paper presents a novel wheeled probe for the purpose of aiding a surgeon in soft tissue abnormality identification during minimally invasive surgery (MIS), compensating the loss of haptic feedback commonly associated with MIS. Initially, a prototype for validating the concept was developed. The wheeled probe consists of an indentation depth sensor employing an optic fibre sensing scheme and a force/torque sensor. The two sensors work in unison, allowing the wheeled probe to measure the tool-tissue interaction force and the rolling indentation depth concurrently. The indentation depth sensor was developed and initially tested on a homogenous silicone phantom representing a good model for a soft tissue organ; the results show that the sensor can accurately measure the indentation depths occurring while performing rolling indentation, and has good repeatability. To validate the ability of the wheeled probe to identify abnormalities located in the tissue, the device was tested on a silicone phantom containing embedded hard nodules. The experimental data demonstrate that recording the tissue reaction force as well as rolling indentation depth signals during rolling indentation, the wheeled probe can rapidly identify the distribution of tissue stiffness and cause the embedded hard nodules to be accurately located.

Clinical indication for intraoperative 3D imaging during open reduction of fractures of the neck and head of the mandibular condyle

PURPOSE

This study aimed to evaluate the use of intraoperative cone-beam computed tomography (CBCT) in monitoring the results of repositioning and osteosynthesis of condylar process and head (capitulum) fractures of the mandible to see if CBCT is beneficial for these patients.

PATIENTS AND METHODS

Sixty patients (22 females and 38 males, age range 16-79 years, average 36.5 years) with condylar process and head fractures according to the classification of Spiessl and Schroll were treated during the study period. Thirty-four of the 60 patients received a CBCT scan immediately after surgical treatment under aseptic conditions.

RESULTS

In all 34 cases, intraoperative CBCT provided high-quality imaging of the condylar process in all three planes. In four patients (11.8%), unsatisfactory reposition or unexpected complications were detected which could immediately be corrected with a surgical revision.

CONCLUSION

Intraoperative use of CBCT enables optimization of the surgical outcome for fractures of the condylar process and head of the mandible, reduces postoperative complications, and spares patients from repeated intervention. In addition, intraoperative CBCT enables safer treatment with minimally invasive approaches.

Cone beam CT for diagnosis and treatment planning in trauma cases

Three-dimensional imaging offers many advantages in making diagnoses and planning treatment. This article focuses on cone beam CT (CBCT) for making diagnoses and planning treatment in trauma-related cases. CBCT equipment is smaller and less expensive than traditional medical CT equipment and is tailored to address challenges specific to the dentoalveolar environment. Like medical CT, CBCT offers a three-dimensional view that conventional two-dimensional dental radiography fails to provide. CBCT combines the strengths of medical CT with those of conventional dental radiography to accommodate unique diagnostic and treatment-planning applications that have particular utility in dentoalveolar trauma cases. CBCT is useful, for example, in identifying tooth fractures relative to surrounding alveolar bone, in determining alveolar fracture location and morphology, in analyzing ridge-defect height and width, and in imaging temporomandibular joints. Treatment-planning applications include those involving extraction of fractured teeth, placement of implants, exposure of impacted teeth, and analyses of airways.

Conebeam CT of the head and neck, part 2: clinical applications

SUMMARY

Conebeam x-ray CT (CBCT) is being increasingly used for point-of-service head and neck and dentomaxillofacial imaging. This technique provides relatively high isotropic spatial resolution of osseous structures with a reduced radiation dose compared with conventional CT scans. In this second installment in a 2-part review, the clinical applications in the dentomaxillofacial and head and neck regions will be explored, with particular emphasis on diagnostic imaging of the sinuses, temporal bone, and craniofacial structures. Several controversies surrounding the emergence of CBCT technology will also be addressed.

A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT). Part II: On 3D model accuracy

AIM

The study aim was to compare the geometric accuracy of three-dimensional (3D) surface model reconstructions between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system.

MATERIALS AND METHODS

A dry human mandible was scanned with five CBCT systems (NewTom 3G, Accuitomo 3D, i-CAT, Galileos, Scanora 3D) and one MSCT scanner (Somatom Sensation 16). A 3D surface bone model was created from the six systems. The reference (gold standard) 3D model was obtained with a high resolution laser surface scanner. The 3D models from the five systems were compared with the gold standard using a point-based rigid registration algorithm.

RESULTS

The mean deviation from the gold standard for MSCT was 0.137 mm and for CBCT were 0.282, 0.225, 0.165, 0.386 and 0.206 mm for the i-CAT, Accuitomo, NewTom, Scanora and Galileos, respectively.

CONCLUSION

The results show that the accuracy of CBCT 3D surface model reconstructions is somewhat lower but acceptable comparing to MSCT from the gold standard.

A comparative evaluation of Cone Beam Computed Tomography (CBCT) and Multi-Slice CT (MSCT) Part I. On subjective image quality

AIMS

To compare image quality and visibility of anatomical structures in the mandible between five Cone Beam Computed Tomography (CBCT) scanners and one Multi-Slice CT (MSCT) system.

MATERIALS AND METHODS

One dry mandible was scanned with five CBCT scanners (Accuitomo 3D, i-CAT, NewTom 3G, Galileos, Scanora 3D) and one MSCT system (Somatom Sensation 16) using 13 different scan protocols. Visibility of 11 anatomical structures and overall image noise were compared between CBCT and MSCT. Five independent observers reviewed the CBCT and the MSCT images in the three orthographic planes (axial, sagittal and coronal) and assessed image quality on a five-point scale.

RESULTS

Significant differences were found in the visibility of the different anatomical structures and image noise level between MSCT and CBCT and among the five CBCT systems (p=0.0001). Delicate structures such as trabecular bone and periodontal ligament were significantly less visible and more variable among the systems in comparison with other anatomical structures (p=0.0001). Visibility of relatively large structures such as mandibular canal and mental foramen was satisfactory for all devices. The Accuitomo system was superior to MSCT and all other CBCT systems in depicting anatomical structures while MSCT was superior to all other CBCT systems in terms of reduced image noise.

CONCLUSIONS

CBCT image quality is comparable or even superior to MSCT even though some variability exists among the different CBCT systems in depicting delicate structures. Considering the low radiation dose and high-resolution imaging, CBCT could be beneficial for dentomaxillofacial radiology.