Factors influencing CAD/CAM accuracy in fibula free flap mandibular reconstruction

La tecnologia CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) ha migliorato sia i risultati funzionali che morfologici nella chirurgia ricostruttiva mandibolare. L\u2019obiettivo del nostro studio \ue8 stato quello di valutare questo tipo di tecnologia ed i fattori che possono influenzare la sua precisione. Un totale di 26 casi di ricostruzione mandibolare con lembo libero di fibula, utilizzando tecnologia CAD/CAM sono stati operati presso l\u2019Unit\ue0 Maxillofacciale della Fondazione IRCCS Ca\u2019 Granda Ospedale Maggiore Policlinico di Milano, da giugno 2014 a febbraio 2018. Abbiamo valutato l\u2019accuratezza confrontando i files STL di pianificazione chirurgica virtuale (obiettivo pianificato) con il file STL di una scansione TC postoperatoria precoce (risultato postoperatorio ottenuto). Entrambi i file STL sono stati importati su Geomagic Studio 2016 (Geomagic Gmbh). In base alla posizione della placca di ricostruzione (punto di riferimento fisso), abbiamo confrontato la deviazione sul condilo sinistro, gonion sinistro, gnathion, gonion destro e condilo destro, per calcolare l\u2019errore medio di deviazione. L\u2019errore medio di deviazione varia da 0,6 mm a 2,2 mm. Solo 2 dei 26 casi analizzati avevano un errore medio uguale o superiore a 2 mm (7,7%). L\u2019area mediana (symphysis-gnathion) ha mostrato una variazione pi\uf9 bassa (1,05 \ub1 0,92 mm) mentre l\u2019area di gonion ha mostrato maggiore variazione (la variazione media del gonion destro e sinistro era rispettivamente di 1,6 mm e 1,46 mm). Nessuno dei possibili fattori (tempi di ricostruzione, malignit\ue0 o benignit\ue0, sito o dimensione del difetto) che potrebbero influenzare la precisione del CAD/CAM, ha mostrato un\u2019influenza significativa. La tecnologia CAD/CAM nella ricostruzione microvascolare dei difetti mandibolari mediante lembo libero di fibula minimizza gli errori umani ed \ue8 considerato come un intervento chirurgico indipendente dall\u2019operatore con alto grado di accuratezza e riproducibilit\ue0.Computer-aided design/computer-aided manufacturing (CAD/CAM) technology has im-proved the functional and morphological results of mandibular reconstructive surgery. The purpose of this study was to objectively assess this technology and factors affecting its accuracy.Fibula free flap mandibular reconstruction was performed in 26 cases us-ing CAD/CAM technology at the Maxillofacial Unit of Fondazione IRCCS Ca\u2019 Gran-da Ospedale Maggiore Policlinico, Milan, between June 2014 and February 2018. We evaluated the technology\u2019s accuracy by comparing the virtual surgical planning STL file (planned-target mesh) with the STL file from an early postoperative CT scan (postopera-tive-achievement mesh) in each case. The STL files were imported into Geomagic Studio 2016 (Geomagic GmbH). According to the position of the reconstruction plate (fixed reference point), we assessed deviations at the right condyle, right gonion, gnathion, left gonion and left condyle, calculating mean, minimum and maximum error values.Mean error values ranged from 0.6 to 2.2 mm; they were 65 2 mm in only 2 (7.7%) cases. The midline area (symphysis-gnathion) showed the least variation (1.05 \ub1 0.92 mm), and the gonion area showed the greatest variation (right and left means of 1.6 and 1.46 mm, respectively). Among all possible factors that could affect CADCAM accuracy, nothing showed significant influence, including the timing of reconstruction, site and size of the defect and malignancy status. CAD/CAM technology has a high degree of accuracy and reproducibility for microvascular reconstruction of mandibular defects using fibula free flaps, regardless of the defect site and length, use of a single- or double-barrel graft or timing of reconstructio

Use of CAD-CAM technology to improve orthognathic surgery outcomes in patients with severe obstructive sleep apnoea syndrome

Introduction: Although multilevel surgery is the mainstay treatment for severe obstructive sleep apnoea syndrome (OSAS), bi-maxillary surgery (maxillomandibular advancement [MMA]) is the most efficacious single procedure for the expansion of the whole pharyngeal airway. MMA is an alternative to the gold standard of continuous positive airway pressure and is equivalent to tracheotomy. Patients and method: Computer-aided design/computer-aided manufacturing (CAD-CAM) technology was used to virtually assess the degree of mandibular and/or maxillary advancement and rotation required to obtain adequate posterior airway space (PAS) in eight patients (seven males, one female). The mean age of the patients was 45.5 years (range, 27\u201351 years), and the average body mass index was 28.9 kg/m2 (range, 21.9\u201331.8 kg/m2). Results: The study group showed significant mandibular advancement, widening of the PAS, and reduction of the apnoea hypopnea index (p < 0.0001, p < 0.0001, and p < 0.0002, respectively). Moreover, patient satisfaction scores regarding postoperative facial profile changes showed excellent compliance. Conclusion: This study demonstrated that bi-maxillary surgery is an efficient single surgical procedure in patients with multilevel OSAS. CAD-CAM technology aided surgeons in performing this operation precisely and enabled patients to expect specific facial profiles

Computer-Aided Design and Computer-Aided Manufacturing Versus Conventional Free Fibula Flap Reconstruction in Benign Mandibular Lesions: An Italian Cost Analysis

PURPOSE: The cost of computer-aided design and computer-aided manufacturing (CAD-CAM) technology has created obstacles for its widespread use despite its several advantages. This study compared the cost of CAD-CAM technology with that of the conventional freehand technique in fibula reshaping for mandibular reconstruction. MATERIALS AND METHODS: A retrospective comparative study was conducted at the Maxillofacial and Dental Unit of the Fondazione Ca' Granda IRCCS Ospedale Maggiore Policlinico (Milan, Italy). The study compared 15 patients in the CAD-CAM group with 10 patients in the conventional freehand group. Only benign pathologic lesions that required at least 3 fibular segments for reconstruction were included. The consumption of resources was estimated using micro-costing analysis (activity-based costing approach). RESULTS: The CAD-CAM group included 15 patients (7 men and 8 women) with a mean age of 42.2 \ub1 1.5 years, and the conventional freehand group included 10 patients (4 men and 6 women) with a mean age of 40.8 \ub1 0.9 years. Although CAD-CAM was a statistically expensive procedure in the perioperative phase (P < .0001), no significant difference was shown in total health care costs between the 2 groups (P = .98). CONCLUSION: CAD-CAM technology had a comparable expense to the conventional freehand technique, specifically for defects requiring at least 3 fibular segments