In-House 3D Printed Positioning and Cutting Guide System for Mandibular Reconstruction. Protocol and case report

Maxillofacial surgery planning has been improved by technological advances in 3D printing. The use of customized cutting and positioning guides allows intraoperative reproduction of pre-planned osteotomy cuts, resulting in increased surgical accuracy, reduced surgical time and improved esthetic and functional outcomes. Our paper presents a new method for creating and printing in-house cutting and positioning guides. A computer program (Brainlab iPlan) was used to segment the mandible for three-dimensional planning from imported conventional computed tomography (CT) scans. The virtual model of the mandible was printed on a stereolithography (SLA) 3D printer and a reconstruction plate was adapted to the printed model. The surface of the model and the screw-retained plate was scanned using a structured light surface 3D scanner (Artec Eva). The obtained scan of the jaw and plate in position was processed and transformed into an STL file. Free software (Autodesk Meshmixer) superimposes the initial jaw on the scanned jaw with the plate, designing a customized hybrid cutting guide that allows accurate intraoperative positioning, knowing the exact position of the reconstruction plate screws in the jaw. The total design, fabrication and 3D printing time for the in-house hybrid guide was 595 min. The average total printing cost was EUR 16. We found the technique to be simple and repeatable. We present and describe here a novel and simple technique for in-house 3D printed positioning and cutting guide system which can be applied to overall maxillofacial area. In cases of mandibular reconstruction, this protocol guarantees an adequate esthetic and functional result. Key words:Oral cancer, 3D surgery, CAD/CAM, personalized medicine, surgical guides, in house.

An Uncommon Great Pretender in Oral Cavity Lesions: The Masson's Tumor

Intravascular papillary endothelial hyperplasia (IPEH) is a rare benign non-neoplastic vascular lesion. A typical presentation consists of a subcutaneous nodule that may simulate other clinical entities. Presentation in the oral cavity is uncommon. It is thought to develop as an abnormal proliferative reaction of endothelial cells in a process of impaired thrombogenesis. When endothelial proliferation occurs, a differential diagnosis with a soft tissue sarcoma, in particular an angiosarcoma, should be performed. We report a case of a 68-year-old female patient who presented with a lesion on the upper lip of 3 months' duration. Surgical resection revealed an IPEH. 1 year later, the patient showed a local recurrence requiring excision with clear margins. Pathological and immunohistochemical features can help us distinguish these lesions from those requiring more aggressive treatment. The gold standard is surgical resection with clear margins. Accurate preoperative diagnosis is essential to avoid overtreatment. Emphasis should be placed on clinical, radiological and histological studies.

Surgical Navigation, Augmented Reality, and 3D Printing for Hard Palate Adenoid Cystic Carcinoma En-Bloc Resection: Case Report and Literature Review

Adenoid Cystic Carcinoma is a rare and aggressive tumor representing less than 1% of head and neck cancers. This malignancy often arises from the minor salivary glands, being the palate its most common location. Surgical en-bloc resection with clear margins is the primary treatment. However, this location presents a limited line of sight and a high risk of injuries, making the surgical procedure challenging. In this context, technologies such as intraoperative navigation can become an effective tool, reducing morbidity and improving the safety and accuracy of the procedure. Although their use is extended in fields such as neurosurgery, their application in maxillofacial surgery has not been widely evidenced. One reason is the need to rigidly fixate a navigation reference to the patient, which often entails an invasive setup. In this work, we studied three alternative and less invasive setups using optical tracking, 3D printing and augmented reality. We evaluated their precision in a patient-specific phantom, obtaining errors below 1 mm. The optimum setup was finally applied in a clinical case, where the navigation software was used to guide the tumor resection. Points were collected along the surgical margins after resection and compared with the real ones identified in the postoperative CT. Distances of less than 2 mm were obtained in 90% of the samples. Moreover, the navigation provided confidence to the surgeons, who could then undertake a less invasive and more conservative approach. The postoperative CT scans showed adequate resection margins and confirmed that the patient is free of disease after two years of follow-up.

Jacob's disease secondary to coronoid process osteochondroma. A case report

The formation of a new joint between a pathologically elongated coronoid process and the body of the malar homolateral bone is known as Jacob's disease. Coronoid process hyperplasia was first described in 1853 by Von Langenbeck, and it was not until 1899 when Oscar Jacob described the disease that it was named after him. Jacobs's disease is an uncommon entity with only a few documented cases in the literature. The condition first manifests with progressive limitation of mouth opening and facial asymmetry. Pain is uncommon and it mainly affects young patients. Different factors have been postulated as possible causes, including temporal muscle hyperactivity, previous trauma, chronic disc displacement of the ipsilateral temporomandibular joint, endocrine stimuli, and genetic alterations. Definitive diagnosis is by histopathology and it is necessary to confirm bone hyperplasia, the presence of cartilage and synovial capsule forming the new joint between the malar bone and the coronoid process. We report a 52-year-old woman patient with a history of childhood trauma in the right preauricular region. She came to our department with a 2-year history of progressive limitation of mouth opening. Computed tomography (CT) revealed a right coronoid process elongation, in contact with the homolateral malar bone, causing it to deform. Surgery with general anesthesia was performed using an intraoral vestibular approach. Histopathology confirmed the diagnoses of Jacob's disease.

Osteochondroma of the mandibular condyle: Resection and reconstruction using vertical sliding osteotomy of the mandibular ramus

Osteochondroma is one of the most common benign bone tumours, although not in the craniofacial region. More than half of these appear in the coronoid process. It can appear on the mandibular condyle, especially in its medial half, and mainly affects women aged around forty years. We present the case of a 51-year-old woman with pain of several months' duration in the right temporomandibular joint (TMJ) and no other symptoms. Panoramic radiography showed an enlarged condyle with no subchondral cysts. Computed tomography showed a bony proliferation with benign signs and a scintigraphy revealed an increased uptake in the condyle. Due to the painful clinical symptoms, a surgical procedure using preauricular and retromandibular approaches was performed to excise the condyle. The resulting defect, which was 9 mm high, was reconstructed by means of a vertical sliding osteotomy of the mandibular ramus and two miniplates for osteosynthesis. Almost two years later, the patient is symptom-free and has a normal opening with no malocclusion or deviation in the opening pattern. We present and discuss different reconstruction options after condylectomy.