Intraosseous Venous Malformation of the Zygomatic Bone: Comparison between Virtual Surgical Planning and Standard Surgery with Review of the Literature

Intraosseous venous malformations affecting the zygomatic bone are infrequent. Primary reconstruction is usually accomplished with calvarial grafts, although the use of virtual surgical planning, cutting guides and patient-specific implants (PSI) have had a major development in recent years. A retrospective study was designed and implemented in patients diagnosed with intraosseous venous malformation during 2006–2021, and a review of the scientific literature was also performed to clarify diagnostic terms. Eight patients were treated, differentiating two groups according to the technique: four patients were treated through standard surgery with resection and primary reconstruction of the defect with calvarial graft, and four patients underwent resection and primary reconstruction through virtual surgical planning (VSP), cutting guides, STL models developed with CAD-CAM technology and PSI (titanium or Polyether-ether-ketone). In the group treated with standard surgery, 75% of the patients developed sequelae or morbidity associated with this technique. The operation time ranged from 175 min to 210 min (average 188.7 min), the length of hospital ranged from 4 days to 6 days (average 4.75 days) and the postoperative CT scan showed a defect surface coverage of 79.75%. The aesthetic results were “excellent” in 25% of the patients, “good” in 50% and “poor” in 25%. In the VSP group, 25% presented sequelae associated with surgical treatment. The operation time ranged from 99 min to 143 min (average 121 min), the length of hospital stay ranged from 1 to 2 days (average of 1.75 days) and 75% of the patients reported “excellent” results. Postoperative CT scan showed 100% coverage of the defect surface in the VSP group. The multi-stage implementation of virtual surgical planning with cutting guides, STL models and patient-specific implants increases the reconstructive accuracy in the treatment of patients diagnosed with intraosseous venous malformation of the zygomatic bone, reducing sequelae, operation time and average hospital stay, providing a better cover of the defect, and improving the precision of the reconstruction and the aesthetic results compared to standard technique.

Assessing The Reliability of Zygomatic Bone Landmarks as Guides to Reach The Inferior Orbital Fissure in Orbitozygomatic Osteotomy. Anatomical Study Of 83 Human Skulls.

ObjectivesTo perform an adequate orbito-zygomatic craniotomy, it is very important that the bone cut which passes through the body of the zygoma reaches the inferior orbital fissure (IOF). To reach the IOF, two surface landmarks on the body of the zygoma are described: a point located directly superior to the malar eminence and the zygomaticofacial foramen. The article explores the reliability of these landmarks and three other alternative points to reach the IOF.Method Eighty-three adult skulls were used in this study. The IOF dimensions and the relationship with the malar eminence, the point superior to the malar eminence, the zygomaticofacial foramen and 3 alternative points (E, C, F) were analyzed.Results. The malar eminence was unacceptable for use as a guide to the IOF. The point superior to the malar eminence was also unacceptable as a guide as only 9.4% and 10.9% were in the projection of the IOF on the right and left, respectively. 59.7% of the total zygomaticofacial foramina fell in the IOF projection. The point F fell in the projection of the IOF in 98.8% and 100.0% on the right and left, respectively. Conclusion. The use of the malar eminence as a guide to reach the IOF is unreliable in one third of cases as it is not easily identified intraoperatively in these cases. The zygomaticofacial foramen cannot be considered a reliable surgical landmark to reach the IOF. The authors recommend using the point “F” which is reliable in 98.8-100% of cases.

Evaluation of zygomatic bone region for placement of quad zygomatic implants using CBCT in postmenopausal women

Insufficient height and width of the alveolar ridge at the implant site remains with inadequate bone volume following extraction in older age people especially in postmenopausal women. Postmenopausal women are susceptible to primary osteoporosis where more bone resorption than formation is seen resulting in decreased bone mass. Hence the present study aims to evaluate the zygomatic bone region for placement of quad zygomatic implants using CBCT.: A total of 120 CBCT images of female patients who were between the age group of 45 yrs to 65 yrs were taken. The zygomatic bone was evaluated for pneumatisation zones and thickness of zygomatic bone at three different regions i.e., superior, middle and inferior at nine points on zygoma bone along with bone to implant contact (BIC) region using virtual software. The largest thickness in the superior, middle and inferior regions were at Point A2(8.01+/-2.10 mm), Point B2 (7.01+/-1.62 mm), and Point C1 (6.65+/-1.64 mm), respectively. The virtually placed implants at Point A3 (15.92+/-4.16 mm) and Point B2 (12.02+/-3.62 mm) had the highest BICs. : To obtain the largest BICs, results suggested that the posterosuperior region (Point A3) and the centre of zygoma (Point B1) were the optimal places for the placement of quad zygomatic implants.

Reduction of Zygomatic Bone Fracture by Two Different Treatment Protocols

Background: Zygomatic bone, a malar bone or cheekbone usually works as eye socket. All over the world, around 15 to 20 million people are traumatized with road accidents. Over 50% of these statistics are diagnosed with zygomatic fractured bone. There are different approaches of therapy to treat zygomatic fractured bone. In this research, two approaches have been studied. The Percutaneous Hook approach is extraoral while Keen’s approach is intraoral. The objective of this study was to evaluate outcomes of two different treatment protocols (percutaneous bone hook method and Keen’s method) for reduction of zygomatic bone fracture. Methods: This comparative analytical study conducted at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Liaquat University Hospital, Hyderabad, Pakistan. Subjects with displaced isolated zygomatic bone fracture were divided in two groups, Group A (Percutaneous Hook Method) and Group B (Keen’s Method). The data was analyzed through SPSS and p<0.05 was considered as statistically significant. Results: Males were predominantly affected in both groups as compared to females i.e., Group A male patients were 22(73.52%) while in Group B male patients were 23(79.41%). Road traffic accidents were the most common etiological factor in both groups. There was a significant difference between the groups in diplopia, cheek flattening and mean mouth opening at postoperative 2nd, 4th and 6th week. The obtained p-value=0.01 was less than 0.05; therefore, the results were statistically significant. Conclusion: It was observed that percutaneous hook method had better outcomes compared to Keen’s method in reducing isolated zygomatic bone fracture. Keywords: Bone Fracture; Treatment Protocols; Zygoma.

A zygomatic bone study using virtual dental implant planning software

This study evaluated the anatomical factors that influence the virtual planning of zygomatic implants by using cone beam computerized tomography (CBCT) scans. CBCT scans of 268 maxilla edentulous patients were transferred to a specialized implant planning software (Galaxis, Sirona) for the following measurements: maxillo-sinus concavity size (small, medium, and large), Zygoma width, implant insertion angle, implant length, and implant apical anchorage. Concavity sizes found were as follows: 34.95% small, 52.30% medium, and 7.35% large. The mean insertion angle was 43.2 degrees and the average implant apical anchorage was 9.1mm. The most frequent implant length was 40mm. Significant differences were found when the different types of concavities in relation to the installation angle, the distance of the apical portion of the implant in contact with the zygomatic bone and the lateral-lateral thickness of the zygomatic bone were compared (p&lt;0.001). Medium-sized maxillary sinus concavity presented greater apical anchorage of the implant (9.7mm) and was the most frequent type (52.30%). The zygomatic bone is a viable site for zygomatic fixtures and the use of specialized implant planning software is an important tool to achieve predictable outcomes for zygomatic implants and allows good visualization of the implant-anatomical structures relation.