Intraoperative navigation in the maxillofacial area based on 3D imaging obtained by a cone-beam device

Controversies and Contemporary Management of Orbital Floor Fractures

Substantial controversy exists regarding the timing of intervention and management of patients with orbital floor fractures. Recent advances in computer-aided technology, including the use of 3-dimensional printing, intraoperative navigational imaging, and the use of novel implants, have allowed for improvement in prospective management modalities. As such, this article aims to review the indications and timing of repair, surgical approaches, materials used for repair, and contemporary adjuncts to repair. Indications for orbital floor fracture repair remain controversial as many of these fractures heal without intervention or adverse sequelae. Intraoperative navigation and imaging, as well as endoscopic guidance, can improve visualization of defects mitigating implant positioning errors, thereby reducing the need for secondary corrective procedures. Patient-specific implants may be constructed to fit the individual patient's anatomy using the preoperative CT dataset and mirroring the contralateral unaffected side and have been shown to improve pre-operative efficiency and minimize postoperative complications. With increased data, we can hope to form evidence-based indications for using particular biomaterials and the criteria for orbital defect characteristics, which may be best addressed by a specific surgical approach.

Radiographic Evaluation of Prosthodontic Patients

This article focuses on radiographic imaging with regard to planning, treating, and maintaining partially and completely edentulous prosthodontic patients with dental implants. Cone-beam computed tomography (CBCT) is the preferred imaging method for pretreatment dental implant treatment planning. Radiographic guides containing radiopaque materials and/or fiducial markers transfer both the proposed prosthesis design and desired implant location for appropriate radiographic evaluation. The three-dimensional CBCT analysis provides information on the adjacent relevant anatomy, bone volume of the edentulous sites, and restorative space assessment.

Application of Navigation Surgery in Temporomandibular Joint Ankylosis Case and Review of Literature

The aim of this article is to develop a navigation-guided oral and maxillofacial surgery including surgical planning, simulation and navigation in temporomandibular joint ankylosis case practiced in tertiary care hospital. After getting the computed tomographic angiography of head and neck, the special software of Brain lab^® is used to mark the arteries and veins of the patient, which was in close approximation to the mandibular condyle. Brain lab^® navigation system was used during the surgery to ascertain the middle meningeal artery location, and osteotomy cut was given. Navigation technology use in the neurosurgery is not new. But its use in the subcontinent in the field of maxillofacial surgery is quite rare. First time, it has been used scientifically in temporomandibular joint ankylosis case. Navigation technology use in the maxillofacial surgery requires a holistic imaginative/creative approach to make the surgeries more predictive and safe.

Intraoperative Image-Guided Navigation in Craniofacial Surgery: Review and Grading of the Current Literature

INTRODUCTION

Image-guided navigation has existed for nearly 3 decades, but its adoption to craniofacial surgery has been slow. A systematic review of the literature was performed to assess the current status of navigation in craniofacial surgery.

METHODS

A Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) systematic review of the Medline and Web of Science databases was performed using a series of search terms related to Image-Guided Navigation and Craniofacial Surgery. Titles were then filtered for relevance and abstracts were reviewed for content. Single case reports were excluded as were animal, cadaver, and virtual data. Studies were categorized based on the type of study performed and graded using the Jadad scale and the Newcastle-Ottawa scales, when appropriate.

RESULTS

A total of 2030 titles were returned by our search criteria. Of these, 518 abstracts were reviewed, 208 full papers were evaluated, and 104 manuscripts were ultimately included in the study. A single randomized controlled trial was identified (Jadad score 3), and 12 studies were identified as being case control or case cohort studies (Average Newcastle-Ottawa score 6.8) The most common application of intraoperative surgical navigation cited was orbital surgery (n = 36), followed by maxillary surgery (n = 19). Higher quality studies more commonly pertained to the orbit (6/13), and consistently show improved results.

CONCLUSION

Image guided surgical navigation improves outcomes in orbital reconstruction. Although image guided navigation has promise in many aspects of craniofacial surgery, current literature is lacking and future studies addressing this paucity of data are needed before universal adoption can be recommended.

Improved Virtual Planning for Bimaxillary Orthognathic Surgery

Conventional model surgery planning for bimaxillary orthognathic surgery can be laborious, time-consuming and may contain potential errors; hence three-dimensional (3D) virtual orthognathic planning has been proven to be an efficient, reliable, and cost-effective alternative. In this report, the 3D planning is described for a patient presenting with a Class III incisor relationship on a Skeletal III base with pan facial asymmetry complicated by reverse overjet and anterior open bite. A combined scan data of direct cone beam computer tomography and indirect dental scan were used in the planning. Additionally, a new method of establishing optimum intercuspation by scanning dental casts in final occlusion and positioning it to the composite-scans model was shown. Furthermore, conventional model surgery planning was carried out following in-house protocol. Intermediate and final intermaxillary splints were produced following the conventional method and 3D printing. Three-dimensional planning showed great accuracy and treatment outcome and reduced laboratory time in comparison with the conventional method. Establishing the final dental occlusion on casts and integrating it in final 3D planning enabled us to achieve the best possible intercuspation.

Orbital reconstruction in the dog, cat, and horse

OBJECTIVE

To describe an adaptable method for reconstruction of the orbit following partial orbitectomy.

ANIMALS STUDIED

One horse, one cat, and four dogs.

PROCEDURE(S)

Following partial orbitectomy for removal of bone and soft tissue affected by pathologic processes, reconstruction was achieved. Cerclage wires were used to reconstitute the orbital rim and other salient facial contours involved in excisions. These wires were then covered with a prolene mesh, first inside the orbit and then outwards over the affected extraorbital areas. Thereafter, a collagen sheet was placed over the mesh. Finally, subcutis and skin were closed over the construct.

RESULTS

All operated eyes remained visual with normal position, direction, and mobility. Eyelid function, tear production, and nasolacrimal function were preserved. Side effects were mild and temporary, but animals requiring a lateral-posterior surgical approach experienced concavity to the side of the head posterior to the orbital ligament region. One bone tumor out of three recurred.

CONCLUSIONS

The reconstruction method presented offers excellent results tectonically, cosmetically, and functionally, even following extensive orbitectomy. By adapted application of three reconstruction steps using readily available materials, large defects may be surgically repaired. Once orbitectomy is mastered, reconstruction requires no additional specialized techniques or equipment.

CAD/CAM splint based on soft tissue 3D simulation for treatment of facial asymmetry

BACKGROUND

Most cases of facial asymmetry involve yaw deformity, and determination of the yaw correction level is very difficult.

METHODS

We use three-dimensional soft tissue simulation to determine the yaw correction level. This three-dimensional simulation is based on the addition of cephalometric prediction to gradual yaw correction. Optimal yaw correction is determined visually, and an intermediate splint is fabricated with computer-aided design and computer-aided manufacturing. Application of positioning devices and the performance of horseshoe osteotomy are advisable.

RESULTS

With this procedure, accurate repositioning of jaws was confirmed and patients obtained fairly good facial contour.

CONCLUSIONS

This procedure is a promising method for a widespread, predictable treatment of facial asymmetry.

Intraoperative navigation for single-splint two-jaw orthognathic surgery: From model to actual surgery

OBJECTIVE

This study reported an intraoperative navigation system for single-splint two-jaw orthognathic surgery, and assessed the accuracy of transferring the computer assisted surgical simulation.

METHODS

A skull model was used for validation, and twenty patients receiving such procedure were enrolled. The procedure contained five phases, including virtual surgery on three-dimensional images, fabrication of surgical positioning guides, preparation of registration and validation landmarks, confirmation of bony position during surgery, and postoperative assessment. Target registration error (TRE) and differences between simulation (T0) and postoperative images (T1) were measured from landmarks to Frankfort horizontal plane (FHP), mid-sagittal plane (MSP), and coronal plane (COP).

RESULTS

For the model experiment, mean TRE was lowest using the hard tissue landmarks (0.60 ± 0.27 mm), and the mean difference (T1-T0) was less than 1 mm to all three planes. For the patients, mean TRE was 1.07 ± 0.18 mm from the hard tissue landmarks. The mean difference was 0.96. ± 0.60 mm from MSP, 1.39 ± 1.11 mm from FHP, and 2.12 ± 1.82 mm from COP. The differences were not significant. Both surgeons and patients were satisfied with the surgical outcome.

CONCLUSION

This study showed that the navigation system had acceptable accuracy and was useful for the two-jaw orthognathic surgery using single-splint method.

Clinical utility of dental cone-beam computed tomography: current perspectives

Panoramic radiography and computed tomography were the pillars of maxillofacial diagnosis. With the advent of cone-beam computed tomography, dental practice has seen a paradigm shift. This review article highlights the potential applications of cone-beam computed tomography in the fields of dental implantology and forensic dentistry, and its limitations in maxillofacial diagnosis.

Surgical navigation in reconstruction

Navigational systems are paramount in solving today's traffic dilemmas, and have important applications in the human body. Current imaging must be diagnostic and is often dictated by the radiologist, but it is up to the surgeon to consider surgical procedures and to decide in which case surgical navigation (SN) has advantages. Knowledge of the surgical capabilities of SN is indispensable. The aims of this article are to support real-time image-guided SN, present routine and advanced cases with precise preoperative planning, and show the scientific capabilities of SN.

Computer-assisted orthognathic surgery: feasibility study using multiple CAD/CAM surgical splints

OBJECTIVE

We present a virtual planning protocol incorporating a patented 3-surgical splint technique for orthognathic surgery. The purpose of this investigation was to demonstrate the feasibility and validity of the method in vivo.

MATERIALS AND METHODS

The protocol consisted of (1) computed tomography (CT) or cone-beam computed tomography (CBCT) maxillofacial imaging, optical scan of articulated dental study models, segmentation, and fusion; (2) diagnosis and virtual treatment planning; (3) computed-assisted design and manufacture (CAD/CAM) of the surgical splints; and (4) intraoperative surgical transfer. Validation of the accuracy of the technique was investigated by applying the protocol to 8 adult class III patients treated with bimaxillary osteotomies. The virtual plan was compared with the postoperative surgical result using image fusion of CT/CBCT dataset by analysis of measurements between hard and soft tissue landmarks relative to reference planes.

RESULTS

The virtual planning approach showed clinically acceptable precision for the position of the maxilla (<0.23 mm) and condyle (<0.19 mm), marginal precision for the mandible (<0.33 mm), and low precision for the soft tissue (<2.52 mm).

CONCLUSIONS

Virtual diagnosis, planning, and use of a patented CAD/CAM surgical splint technique provides a reliable method that may offer an alternate approach to the use of arbitrary splints and 2-dimensional planning.

Comparison of cone-beam and conventional multislice computed tomography for image-guided dental implant planning

OBJECTIVES

To compare the accuracy of cone-beam CT (CBCT) and multislice CT (MSCT) with regard to its use in image-guided dental implant surgery in a prospective model based study.

MATERIAL AND METHODS

Ten photopolymer-acrylate mandibula models, each with four precise metal reference markers, were scanned with MSCT and CBCT. The six reference distances between the markers were measured by a three-axis milling machine first. The distances were then measured by (1) navigation with the Medtronic StealthStation® TREON™ image-guided surgery system, (2) with the Medtronic planning-tool and (3) on the PC with the Mimics® software. Mean values were calculated for all three methods for CBCT and MSCT and were compared for statistical significance.

RESULTS

Of all measurements, 83% of the arithmetic mean values were within the ±0.5 mm range (MSCT 88% and CBCT 78%) and 17% within the ±1.0 mm range (MSCT 12% and CBCT 22%). The absolute difference of the arithmetic mean values showed no statistically significant difference between MSCT and CBCT. The difference of the overall mean values to the reference was 0.43 mm for MSCT and 0.46 mm for CBCT.

CONCLUSIONS

The data of our study prove that the application of CBCT for the indicated purpose yielded good results comparable to those of MSCT. All three measuring methods were feasible and accuracy was statistically not different between the data acquired by MSCT and CBCT within the setting of this study.

New Methods to Evaluate Craniofacial Deformity and to Plan Surgical Correction

The success of cranio-maxillofacial (CMF) surgery depends not only on surgical techniques, but also upon an accurate surgical plan. Unfortunately, traditional planning methods are often inadequate for planning complex cranio-maxillofacial deformities. To this end, we developed 3D computer-aided surgical simulation (CASS) technique. Using our CASS method, we are able to treat patients with significant asymmetries in a single operation which in the past was usually completed in two stages. The purpose of this article is to introduce our CASS method in evaluating craniofacial deformities and planning surgical correction. In addition, we discuss the problems associated with the traditional surgical planning methods. Finally, we discuss the strength and pitfalls of using three-dimensional measurements to evaluate craniofacial deformity.

Reliability and reproducibility of linear mandible measurements with the use of a cone-beam computed tomography and two object inclinations

OBJECTIVE

The aim of this study was to assess the influence of inclination of the object on the reliability and reproducibility of linear measurements of anatomic structures of the mandible on images obtained using cone-beam CT (CBCT).

METHODS

Ten linear dimensions between anatomical landmarks were measured in a dry mandible. The measurements were performed with a manual calliper three times by three observers. The mandible was scanned with Planmeca Promax 3D cone-beam CT (Planmeca Oy, Helsinki, Finland) with the base of the mandible parallel as well as tilted 45° to the horizontal plane. Computer measurements of the linear dimension were performed by three observers. The radiographic measurements were performed four times for each experimental setting. A total of 240 measurements were performed. Reproducibility was evaluated through comparison of standard deviation (SD) and estimation of intraclass correlation coefficient (ICC). The error was estimated as the absolute difference between the radiographic measurements and the mean manual calliper measurements.

RESULTS

The mean SD for the radiographic measurements was 0.36 mm for the horizontally positioned mandible and 0.48 mm for the inclined mandible. The ICC between examiners was 0.996 mm, between sessions was 0.990 mm and between CBCT measurements and calliper was 0.992 mm. The overall absolute mean measurement error was 0.40 mm (SD 0.39 mm). The percentage of errors that exceeded 1 mm was 6.7%.

CONCLUSION

The results revealed high reliability of measurements performed on CBCT images independently from object position, examiner's experience and high reproducibility in repeated measurements settings.

Advances in medical robotic systems with specific applications in surgery--a review

Although robotics was started as a form of entertainment, it gradually became used in different branches of science. Medicine, particularly in the operating room, has been influenced significantly by this field. Robotic technologies have offered valuable enhancements to medical or surgical processes through improved precision, stability and dexterity. In this paper we review different robotics and computer-assisted systems developed with medical and surgical applications. We cover early and recently developed systems in different branches of surgery. In addition to the united operational systems, we provide a review of miniature robotic, diagnostic and sensory systems developed to assist or collaborate with a main operator system. At the end of the paper, a discussion is given with the aim of summarizing the proposed points and predicting the future of robotics in medicine.

Comparison of actual surgical outcomes and 3-dimensional surgical simulations

PURPOSE

The advent of imaging software programs has proved to be useful for diagnosis, treatment planning, and outcome measurement, but precision of 3-dimensional (3D) surgical simulation still needs to be tested. This study was conducted to determine whether the virtual surgery performed on 3D models constructed from cone-beam computed tomography (CBCT) can correctly simulate the actual surgical outcome and to validate the ability of this emerging technology to recreate the orthognathic surgery hard tissue movements in 3 translational and 3 rotational planes of space.

MATERIALS AND METHODS

Construction of pre- and postsurgery 3D models from CBCTs of 14 patients who had combined maxillary advancement and mandibular setback surgery and 6 patients who had 1-piece maxillary advancement surgery was performed. The postsurgery and virtually simulated surgery 3D models were registered at the cranial base to quantify differences between simulated and actual surgery models. Hotelling t tests were used to assess the differences between simulated and actual surgical outcomes.

RESULTS

For all anatomic regions of interest, there was no statistically significant difference between the simulated and the actual surgical models. The right lateral ramus was the only region that showed a statistically significant, but small difference when comparing 2- and 1-jaw surgeries.

CONCLUSIONS

Virtual surgical methods were reliably reproduced. Oral surgery residents could benefit from virtual surgical training. Computer simulation has the potential to increase predictability in the operating room.

Three-dimensional reconstruction of a fibro-osseous lesion using binary images transformed from histopathological images

The aim of this report was to introduce a new method of three-dimensional (3D) reconstruction for fibro-osseous lesions (FOLs) using binary images transformed from histopathological images and to describe its usefulness. A sample of multiconfluent FOL was used (one of the five types of FOL according to a radiographic classification) which was diagnosed histopathologically as ossifying fibroma. Approximately 30 pathological images were assembled into a composite image of the slide using Tiling Boutique software version 3 for Windows (Sanyo Electric, Osaka, Japan). The tiling images were transformed into 8-bit scale images and then into binary images using ImageJ software ver.1.37 (National Institutes of Health, Bethesda, MD). These images were used for 3D reconstruction using ImageJ software. Images were loaded at the same matrix size and were reconstructed into layers of two-dimensional image stacks, adjusted so that contiguous images were aligned based on their centre points, and arranged with long axes horizontal. 3D findings aided the visual understanding of morphological features in the lesion. The 3D reconstruction can be displayed with arbitrary rotation. In this case, the 3D reconstruction, using Real Image software version 4.01 for Windows (KGT, Tokyo, Japan), was created from an arbitrary section. This allowed us to determine the pattern of calcification between groups of connected osteoids and to compare the internal structure of such lesions that are not visible on histopathological findings. Differentiation of features was even more pronounced with a two colour display indicating fibrous connective tissue and osteoid tissue. A 3D reconstruction of a multiconfluent ossifying fibroma was created using binary images transformed from histopathological images. The quality of the images depends above all on the functionality of the image-processing software. Comparison of each pattern of FOL might allow more simple assessment of the morphological features of FOLs.

Clinical use of navigation based on cone-beam computer tomography in maxillofacial surgery

Image-guidance in maxillofacial surgery is based predominantly on computed tomographic (CT) images. Its main disadvantage is the considerable amount of radiation to which the patient is exposed, and dental metal artefacts. Recently, a new class of devices based on the concept of cone-beam computed tomography (CBCT) has been introduced for maxillofacial imaging, which we have investigated. In a clinical study, the first seven patients to be operated using a navigation system based on CBCT images, were evaluated. In all cases patient to image recording was uneventful and the surgical objective was reached. The guidance given by the navigation system was helpful. CBCT is an alternative to conventional CT, gives a lower dose of radiation, and costs less. Limitations in the quality of the images and the size of the field of view may restrict its use. It is suitable for image-guided surgery using a navigation system as long as the images show enough of the relevant anatomy and pathology.

The accuracy of image guided surgery based on cone beam computer tomography image data

OBJECTIVE

The objective of this study was to verify if accurate patient-to-image registration for precision navigation in maxillofacial surgery is possible based on cone beam computed tomography (CBCT) image data.

STUDY DESIGN

A maxillary registration template was placed on a standard plastic skull phantom that was equipped with a custom made model of the maxilla and with target markers. Imaging was performed with a CBCT device (Newtom 9000 Digital Volume Tomograph (DVT), QR s.r.l., Verona, Italy) and a computed tomography (CT) scanner (Somatom 4, Siemens, Forchheim, Germany). Using an infrared navigation system (Polaris, NDI, Waterloo, Ontario), multiple pair-point registration of both image data sets and the phantom were performed. The target registration error (TRE) was evaluated.

RESULTS

A total of 243 registrations were performed for either image data set. The spatial distribution of TRE on the skull showed increasing inaccuracy with growing distance from the registration markers. The average target registration error was 1.50 +/- 0.82 mm with CBCT and 1.57 +/- 0.84 mm with CT image data and did not differ significantly. Error distribution correlated strongly between CT- and CBCT-based registration.

CONCLUSIONS

The overall registration accuracy based on CBCT image data was similar to CT. The strong correlation of the geometric distribution of TRE between CT- and CBCT-based measurements proves that CBCT can be equivalent to CT in image-guided maxillofacial surgery.