(73) From Virtual to Reality: Computer Guided Mid-Face Reconstruction Using Free Osseous Flaps

Abstract:
Statement of the Problem: The mid-face bony defects are challenging, complex and make the desired functional and esthetic outcomes of the reconstruction hard to reach due to subunits anatomical considerations such as restoring the previous orbital volume and support in order to correct enophthalmos, dystopia and diplopia, keep the nasal airway patent, provide malar projection, infra-orbital and lateral orbital rims contouring identical to the contralateral non-defected side otherwise cosmetic deformities occur, need to close the oronasal communication and the desired bony volume and position for dental implant placement. All these criteria make it difficult; even impossible in some cases to reconstruct such defects in free-hand traditional ways.
Material and

Methods: A retrospective study is performed on patients of complex mid-face defects including maxillary, infra-orbital and lateral orbital rims and zygoma between 2019 and 2024. The (VP) and computer-guided reconstruction were utilized in all patients with microvascular osseous free flaps (n = 78). A preoperative contrast-enhanced CT on head and neck region are required for virtual planning and designing of the osseous flap mimicking the previous challenging anatomic contour of the mid-face. Also, CT angiography of lower limbs in cases of fibula free flap, iliac bone in case of DCIA free flap and shoulder in case of scapula free flap; were required for virtual planning and designing of the osteotomy guides and patient-specific plates. All the (VP) workflow was designed by our team surgeons using Materialise softwares.
Results and Data Analysis: 78 patients of complex mid-face defects categorized according to Brown classification of mid-face complex defects as following; 37 class II, 9 Bilateral class II, 27 class III, 5 class IV. 69 of the defects were post tumor resection, 9 of defects were post gunshot injury. Lesions were histo-pathologically proven as 18 Squamous cell carcinoma, 12 muco-epidermoid carcinoma, 4 adenoid cystic carcinoma, 2 osteosarcoma, 4 chondrosarcoma, 6 Mucormycosis, 13 ameloblastoma, 7 odontogenic keratocyst, 3 arteriovenous malformations. There were 30 females and 48 males. Reconstruction was utilizing full computer-guided surgical protocol with 57 fibular free flap, 9 DCIA free flap, 12 scapula free flap. The approach utilized for dissection and flap setting was endo-oral in 46 patients (59%) and weber-Fergusson in 32 patients (41%) .77 free flaps (98.7%) were succeeded and just one (1.3%) free flap failure; DCIA. The recipient artery of anastomosis was the facial artery in 46 patients, the external carotid artery in 23 patients and the superfacial temporal vessels in 9 patients. Dental rehabilitation was carried out in 72 patients (92.3%); by dental implants in 68 patients (87.1%) and removable prosthesis in the remaining 4 patients (5.1%). Esthetic results were perfect (identical superimposition between preoperative virtual planning and postoperative CT radiograph in the 3 dimensions) in 71 patients (91%).

Conclusion: Preoperative (VP), 3D modeling and computer-guided design of osteotomy guides and custom-made plates offers a lot of benefits for the patients of complex mid-face defects, dramatically reducing the operation time and efforts and magnificently improvement of the functional and esthetic outcomes. That makes utilizing them mandatory not fantasy.

References:
1.Elsharabasy IM, Elhafez HAEA, Ahmed SAE, Ayad WM. Evaluation of the Accuracy of Three-Dimensional Virtual Surgical Planning for Reconstruction of Mandibular Defects Using Free Fibular Flap. J Craniofac Surg. 2020 Jun;31(4):950-955. doi: 10.1097/SCS.0000000000006280. PMID: 32149975.
2.Swendseid BP, Roden DF, Vimawala S, Richa T, Sweeny L, Goldman RA, Luginbuhl A, Heffelfinger RN, Khanna S, Curry JM. Virtual Surgical Planning in Subscapular System Free Flap Reconstruction of Midface Defects. Oral Oncol. 2020 Feb;101:104508. doi: 10.1016/j.oraloncology.2019.104508. Epub 2019 Dec 19. PMID: 31864958.C
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