Giovanni Badiali

Simulation-guided Navigation: A New Approach to Improve Intraoperative Three-dimensional Reproducibility During Orthognathic Surgery

Because of the recent development of three-dimensional technology, computer software is increasingly being used for diagnosis, analysis, data documentation, and surgical planning for orthognathic surgery. Currently, the typical method to reposition jaws in the correct and planned location is based on the use of surgical splints, which have a quite high level of imprecision. The most important differences between planned and achieved maxillary movements are in the vertical and rotational positioning. Several methods have been described for intraoperative maxillary control, but none of these procedures is satisfactory. We present a new method to transfer individualized three-dimensional virtual planning of the patient using a navigation system in the operating room to improve reproducibility of the simulation. We enrolled 10 patients with dentofacial deformities from November 2008 to May 2009. All patients were studied and treated according to the following steps: cone-beam computed tomography data acquisition, virtual simulation of the surgical procedure, surgery with intraoperative navigation, and validation through reproducibility evaluation. We found 86.5% mean preoperative surgical plan reproducibility with the assistance of simulation-guided navigation compared with 80% mean reproducibility obtained in our previous group, in which no intraoperative navigation was performed. According to these results, we can assume that simulation-guided navigation would be a helpful procedure during orthognathic surgery to improve reproducibility of the preoperative virtual surgical planning.

Augmented reality as an aid in maxillofacial surgery: validation of a wearable system allowing maxillary repositioning.

AIM We present a newly designed, localiser-free, head-mounted system featuring augmented reality as an aid to maxillofacial bone surgery, and assess the potential utility of the device by conducting a feasibility study and validation. METHODS Our head-mounted wearable system facilitating augmented surgery was developed as a stand-alone, video-based, see-through device in which the visual features were adapted to facilitate maxillofacial bone surgery. We implement a strategy designed to present augmented reality information to the operating surgeon. LeFort1 osteotomy was chosen as the test procedure. The system is designed to exhibit virtual planning overlaying the details of a real patient. We implemented a method allowing performance of waferless, augmented-reality assisted bone repositioning. In vitro testing was conducted on a physical replica of a human skull, and the augmented reality system was used to perform LeFort1 maxillary repositioning. Surgical accuracy was measured with the aid of an optical navigation system that recorded the coordinates of three reference points (located in anterior, posterior right, and posterior left positions) on the repositioned maxilla. The outcomes were compared with those expected to be achievable in a three-dimensional environment. Data were derived using three levels of surgical planning, of increasing complexity, and for nine different operators with varying levels of surgical skill. RESULTS The mean error was 1.70 ± 0.51 mm. The axial errors were 0.89 ± 0.54 mm on the sagittal axis, 0.60 ± 0.20 mm on the frontal axis, and 1.06 ± 0.40 mm on the craniocaudal axis. The simplest plan was associated with a slightly lower mean error (1.58 ± 0.37 mm) compared with the more complex plans (medium: 1.82 ± 0.71 mm; difficult: 1.70 ± 0.45 mm). The mean error for the anterior reference point was lower (1.33 ± 0.58 mm) than those for both the posterior right (1.72 ± 0.24 mm) and posterior left points (2.05 ± 0.47 mm). No significant difference in terms of error was noticed among operators, despite variations in surgical experience. Feedback from surgeons was acceptable; all tests were completed within 15 min and the tool was considered to be both comfortable and usable in practice. CONCLUSION We used a new localiser-free, head-mounted, wearable, stereoscopic, video see-through display to develop a useful strategy affording surgeons access to augmented reality information. Our device appears to be accurate when used to assist in waferless maxillary repositioning. Our results suggest that the method can potentially be extended for use with many surgical procedures on the facial skeleton. Further, our positive results suggest that it would be appropriate to proceed to in vivo testing to assess surgical accuracy under real clinical conditions.

A novel missense mutation in ANO5/TMEM16E is causative for gnathodiaphyseal dyplasia in a large Italian pedigree

Gnathodiaphyseal dysplasia (GDD) is an autosomal dominant syndrome characterized by frequent bone fractures at a young age, bowing of tubular bones and cemento-osseus lesions of the jawbones. Anoctamin 5 (ANO5) belongs to the anoctamin protein family that includes calcium-activated chloride channels. However, recent data together with our own experiments reported here add weight to the hypothesis that ANO5 may not function as calcium-activated chloride channel. By sequencing the entire ANO5 gene coding region and untranslated regions in a large Italian GDD family, we found a novel missense mutation causing the p.Thr513Ile substitution. The mutation segregates with the disease in the family and has never been described in any database as a polymorphism. To date, only two mutations on the same cysteine residue at position 356 of ANO5 amino-acid sequence have been described in GDD families. As ANO5 has also been found to be mutated in two different forms of muscular dystrophy, the finding of this third mutation in GDD adds clues to the role of ANO5 in these disorders.

Cancerization of cutaneous flap reconstruction for oral squamous cell carcinoma: report of three cases studied with the mtDNA D-loop sequence analysis

Foschini M P, Morandi L, Marchetti C, Cocchi R, Eusebi L H, Farnedi A, Badiali G, Gissi D B, Pennesi M G & Montebugnoli L
(2011) Histopathology58, 361–367
Cancerization of cutaneous flap reconstruction for oral squamous cell carcinoma: report of three cases studied with the mtDNA D‐loop sequence analysis

Treatment of intrabony defects after impacted mandibular third molar removal with bioabsorbable and non-resorbable membranes.

BACKGROUND Mandibular second molar (M2) periodontal defects after third molar (M3) removal in high-risk patients are a clinical dilemma for clinicians. This study compares the healing of periodontal intrabony defects at distal surfaces of mandibular M2s using bioabsorbable and non-resorbable membranes. METHODS Eleven patients with bilateral probing depths (PDs) ≥6 mm distal to mandibular M2s and intrabony defects ≥3 mm, related to the total impaction of M3s, were treated with M3 extraction and covering of the surgical bone defect with a bioabsorbable collagen barrier on one side and a non-resorbable expanded polytetrafluoroethylene (ePTFE) barrier contralaterally. The PD, clinical attachment level (CAL), M2 mobility, and furcation class probing were evaluated preoperatively and 3, 6, and 9 months postoperatively. Intraoral periapical radiographs were taken immediately preoperatively and 3 and 9 months postoperatively. RESULTS Both treatment modalities were successful. At 9 months, the mean PD reduction was 5.2 ± 3.9 mm for bioabsorbable sites and 5.5 ± 3.0 mm for non-resorbable sites; the CAL gain was 5.9 ± 3.3 mm and 5.5 ± 3.4 mm, respectively. The outcome difference between the two sites for PD and CAL did not differ statistically (P >0.05) at any assessment time. CONCLUSION Bioabsorbable collagen membranes in guided tissue regeneration treatment of intrabony defects distal to the mandibular M2 obtained the same marked PD reductions and CAL gains as non-resorbable ePTFE membranes after M3 extraction.

Human-PnP: Ergonomic AR Interaction Paradigm for Manual Placement of Rigid Bodies

The human perception of the three-dimensional world is influenced by the mutual integration of physiological and psychological depth cues, whose complexity is still an unresolved issue per se. Even more so if we wish to mimic the perceptive efficiency of the human visual system within augmented reality (AR) based surgical navigation systems. In this work we present a novel and ergonomic AR interaction paradigm that aids the manual placement of a non-tracked rigid body in space by manually minimizing the reprojection residuals between a set of corresponding virtual and real feature points. Our paradigm draws its inspiration from the general problem of estimating camera pose from a set of n-correspondences, i.e. perspective-n-point problem. In a recent work, positive results were achieved in terms of geometric error by applying the proposed strategy on the validation of a wearable AR system to aid manual maxillary repositioning.

Does microvascular free flap reconstruction in oral squamous cell carcinoma improve patient survival

Objective We analyzed our experiences with microvascular reconstruction after oncologic resections for oral squamous cell carcinoma. Has microvascular surgery changed the survival rate of these patients? Design Retrospective study. Subjects and Methods Forty-two consecutive patients enrolled from March 1999 to December 2004. Follow-up time ranged from 1 to 94 months. Survival rates were evaluated by the Kaplan-Meier method and compared among different groups with the use of Cox regression. Results The actuarial 5-year survival rate was 41.9% (SD = 9.6%). Survival rates were also analyzed according to T, N, and stage. The survival was significantly related only to N, which showed a 72.4% increase in the risk related to the increase of one N stage. Conclusions A comparison between our study group and those of 3 previous similar studies would not provide definitive statistical evidence, but it could certainly suggest a trend. The comparison seems to support that microvascular free tissue transfer does not change the survival of these patients.

Computer-assisted piezoelectric surgery: a navigated approach toward performance of craniomaxillofacial osteotomies.

Purpose:The purpose of the current study was to present the clinical applications of a new technique that we term computer-assisted piezoelectric surgery (CAPS). The method marries piezosurgery and navigation to greatly aid the treatment of various maxillofacial problems. Methods:Preliminary applications in orthognathic surgery, craniofacial procedures, orthodontic surgery, and oncology were analyzed retrospectively. Eighteen patients were treated using the CAPS technique in the interval of 2010 to 2013. Results:The technique emphasizing the features that are not possible without the combination of the 2 systems has been analyzed. The technique is safer than other methods, is minimally invasive, and allows the use of a buried or semiburied approach. Conclusions:According to our preliminary experience, CAPS seems to be a valuable new technique for craniomaxillofacial osteotomies.

Navigation in Orthognathic Surgery: 3D Accuracy.

This article aims to determine the absolute accuracy of maxillary repositioning during orthognathic surgery according to simulation-guided navigation, that is, the combination of navigation and three-dimensional (3D) virtual surgery. We retrospectively studied 15 patients treated for asymmetric dentofacial deformities at the Oral and Maxillofacial Surgery Unit of the S.Orsola-Malpighi University Hospital in Bologna, Italy, from January 2010 to January 2012. Patients were scanned with a cone-beam computed tomography before and after surgery. The virtual surgical simulation was realized with a dedicated software and loaded on a navigation system to improve intraoperative reproducibility of the preoperative planning. We analyzed the outcome following two protocols: (1) planning versus postoperative 3D surface analysis; (2) planning versus postoperative point-based analysis. For 3D surface comparison, the mean Hausdorff distance was measured, and median among cases was 0.99 mm. Median reproducibility < 1 mm was 61.88% and median reproducibility < 2 mm was 85.46%. For the point-based analysis, with sign, the median distance was 0.75 mm in the frontal axis, -0.05 mm in the caudal-cranial axis, -0.35 mm in the lateral axis. In absolute value, the median distance was 1.19 mm in the frontal axis, 0.59 mm in the caudal-cranial axis, and 1.02 mm in the lateral axis. We suggest that simulation-guided navigation makes accurate postoperative outcomes possible for maxillary repositioning in orthognathic surgery, if compared with the surgical computer-designed project realized with a dedicated software, particularly for the vertical dimension, which is the most challenging to manage.

Three-dimensional surgical simulation-guided navigation in thoracic surgery: a new approach to improve results in chest wall resection and reconstruction for malignant diseases

OBJECTIVES Oncological surgery of the chest wall should be performed to achieve free margins of at least 2 cm for metastasis or 4 cm for primary tumours. When the lesion is not visible or palpable, difficulty in identification may lead to a larger incision and a resection wider than is necessary. METHODS We report three cases of non-palpable metastatic chest wall lesions in which the preoperative surgical planning and the intraoperative identification of the tumour, and thus the subsequent chest wall reconstruction, was supported using computer-based surgery. RESULTS The application of high-resolution three-dimensional imaging technology and navigational systems is used in preoperative surgical planning to provide virtual simulations of a patients skeletal changes and new soft tissue profile. Intraoperatively, a mobile navigation probe was used to identify the lesion, matching surgical landmarks and the preoperative computed tomography imaging, achieving the radical resection of the tumour with correct but not excessive surgical margins. Two patients underwent partial sternectomy followed by sternal allograft reconstruction. The third patient underwent chest wall resection followed by reconstruction using titanium bars and vicryl mesh. In all cases, the postoperative period was uneventful. After a follow-up period of 13.9 and 8 months, respectively, all patients are disease free, without complications. CONCLUSIONS Application of navigation technology in thoracic surgery should be encouraged because it is easy to use and requires a limited learning curve.