Morphologic features of the mandibular ramus associated with increased surgical time and blood loss in sagittal split-ramus osteotomy.

PURPOSE: To determine whether specific morphologic features of the mandibular ramus can predict increased surgical time and blood loss in sagittal split-ramus osteotomy (SSRO). MATERIALS AND METHODS: The clinical and morphologic features of the mandibular ramus, obtained from computed tomographic images (n=50), were analyzed to predict the surgical time, the time required for ablation of the medial mandibular ramus, and the time required for sectioning of the mandible in performing a modified Obwegeser SSRO. RESULTS: Significant factors associated with surgical time were an anterior border of the ramus at least 10.5 mm wide, a maximal length of the thickened ramus of at least 8.5 mm, and a distance from the mandibular incisor to the posterior border of the mandible of at least 97.5 mm. There were significant differences in blood loss between the 2 axial aspects of the medial ramus. CONCLUSIONS: The greater protrusion of the medial oblique ridge, thickened ramus, and longer distance from the mandibular incisors to the posterior border of the mandible may increase the surgical time and blood loss in patients undergoing classic SSRO. When planning or performing an SSRO, the morphologic features obtained from computed tomographic images may help surgeons gain a better understanding of the potential difficulties when the surgical site involves the medial aspect of the ascending ramus of the mandible.

Prognostic factors for keratocystic odontogenic tumor (odontogenic keratocyst): analysis of clinico-pathologic and immunohistochemical findings in cysts treated by enucleation.

BACKGROUND: The purpose of this study was to determine prognostic factors for the recurrence of keratocystic odontogenic tumors (KCOTs) following simple enucleation by examining clinico-pathologic and immunohistochemical findings. METHODS: Following enucleation, the frequency of recurrence among 32 subjects diagnosed with KCOT was analyzed for tumor site, radiographic and histologic features, and immunopositivity for Ki-67 and p53. RESULTS: Keratocystic odontogenic tumors in four out of 32 subjects (12.5%) recurred during the follow-up period (median: 33 months, range: 7-114 months). Three out of four subjects (75.0%) among recurrent group showed high expression of Ki-67 (LI >10%) in basal layer and four (4/28; 14.3%) among non-recurrence group (P = 0.025). Expression of p53 among non-recurrent group was observed in 11 subjects (11/28; 39.3%), and in three subjects (3/4; 75.0%) among the recurrent group (P = 0.295). Hazard risk for the recurrence of KCOT was 4.02 (95% CI 1.42-18.14) for high Ki-67 expression in the basal layer by the Cox proportional hazard model (P = 0.009). In our study, none of the other clinico-pathologic variables were associated with the recurrence of KCOT. CONCLUSION: The results suggested that the evaluation of Ki-67 expression in KCOT at the time of pathological diagnosis might be helpful for consideration of appropriate adjunctive surgical procedures to avoid a recurrence and may serve as a prognostic marker.

Factors predictive of pterygoid process fractures after pterygomaxillary separation without using an osteotome in Le Fort I osteotomy.

OBJECTIVE: This study demonstrated pterygomaxillary disjunction patterns and elucidated factors related to unfavorable pterygomaxillary junction fractures in Le Fort I osteotomy without using an osteotome. STUDY DESIGN: Clinical and anatomical data obtained from computed tomography images (100 sides) were analyzed for their ability to predict patterns of pterygomaxillary disjunction. RESULTS: Separation of the pterygomaxillary junction was most frequently performed at the maxillary tuberosity (48.0%). Twenty-eight pterygoid plates were fractured. Male gender, increased age, thickness of the pterygomaxillary junction, and length of the maxillary tuberosity were significant risk factors for pterygoid process fractures. We also identified that a pterygomaxillary junction thickness less than 2.6 mm and a maxillary tuberosity length of more than 11.5 mm indicated a statistically significant risk of pterygoid process fractures. CONCLUSIONS: Prediction of frangible pterygoid plates by preoperative quantitative evaluation of morphometric values provides useful information for selecting safe procedures.

Endoscopic-assisted resection of peripheral osteoma using piezosurgery.

Endoscopic-assisted surgery has gained widespread popularity as a minimally invasive procedure, particularly in the field of maxillofacial surgery. Because the surgical field around the mandibular angle is extremely narrow, the surrounding tissues may get caught in sharp rotary cutting instruments. In piezosurgery, bone tissues are selectively cut. This technique has various applications because minimal damage is caused by the rotary cutting instruments when they briefly come in contact with soft tissues. We report the case of a 33-year-old man who underwent resection of an osteoma in the region of the mandibular angle region via an intraoral approach. During surgery, the complete surgical field was within the view of the endoscope, thereby enabling the surgeon to easily resection the osteoma with the piezosurgery device. Considering that piezosurgery limits the extent of surgical invasion, this is an excellent low-risk technique that can be used in the field of maxillofacial surgery.