Computed tomography analysis of the anterior ethmoid genu of the frontal recess in non-diseased sinuses.

OBJECTIVE: Knowledge of anatomical variations of the frontal recess and frontal sinus and recognition of endoscopic landmarks are vital for safe and effective endoscopic sinus surgery. This study revisited an anatomical landmark in the frontal recess that could serve as a guide to the frontal sinus. METHOD: Prevalence of the anterior ethmoid genu, its morphology and its relationship with the frontal sinus drainage pathway was assessed. Computed tomography scans with multiplanar reconstruction were used to study non-diseased sinonasal complexes. RESULTS: The anterior ethmoidal genu was present in all 102 anatomical sides studied, independent of age, gender and race. Its position was within the frontal sinus drainage pathway, and the drainage pathway was medial to it in 98 of 102 cases. The anterior ethmoidal genu sometimes extended laterally and formed a recess bounded by the lamina papyracea laterally, by the uncinate process anteriorly and by the bulla ethmoidalis posteriorly. Distance of the anterior ethmoidal genu to frontal ostia can be determined by the height of the posterior wall of the agger nasi cell rather than its volume or other dimensions. CONCLUSION: This study confirmed that the anterior ethmoidal genu is a constant anatomical structure positioned within frontal sinus drainage pathway. The description of anterior ethmoidal genu found in this study explained the anatomical connection between the agger nasi cell, uncinate process and bulla ethmoidalis and its structural organisation.

Anatomic relationship of nasolacrimal duct and major lateral wall landmarks: cadaveric study with surgical implications.

BACKGROUND: Detailed knowledge of the surgical anatomic landmarks of the lateral nasal wall is important for safe and successful endoscopic sinonasal surgery. We sought to determine the relationship of major landmarks to the nasolacrimal duct (NLD). METHODS: Twenty mid-sagittal head sections of 10 fresh frozen cadavers were studied after removal of the nasal septum. The insertion of the alar cartilage into the maxilla was taken as a fixed point and all measurements were performed in a defined axial plane at the level of the maxillary sinus natural ostium. Two surgeons independently recorded each measurement 3 times with an average of the readings used for statistical analysis. RESULTS: The overall agreement index was excellent (r = 0.84) between the observers. At the level of maxillary ostium, the mean distance from the alar rim to the NLD was 43.05 ± 4.76 mm on the right and 41.25 ± 4.56 mm on the left. The most anterior projection of the middle turbinate head was noted to be anterior to the NLD in 70% of specimens. In positional relationship, the maxillary line was posterior to the NLD in 55%, whereas the bulla ethmoidalis and the free edge of uncinate process were uniformly posterior to the NLD in all the specimens. CONCLUSION: This study provides useful anatomic and positional relationships between the NLD and major lateral wall landmarks. Although the maxillary line and the head of the middle turbinate are often considered useful guides to the position of the ipsilateral NLD, their spatial relationship to the NLD is not consistent. These landmarks, therefore, cannot be solely relied upon during surgery to avoid injury to the NLD.

Clinical Study on Blowout Fractures of the Medial Orbital Wall Reconstructed by Bulla Ethmoidalis Osteomucosal Flap / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Various surgical approaches have been employed to treat fractures of the medial orbital wall. Among them, the transnasal endoscopic approach provides the chance to avoid external scars and to observe the fracture site clearly. These approaches mostly require the use of grafts or splints. Authors carried out a retrospective study on the blowout fractures repaired by bulla ethmoidalis osteomucosal flap (BOMF) and compared them with the groups that were treated with silastic sheet only and with Med-pore(R) registered to investigate the merits of BOMF with respect to results and complications. SUBJECTS AND METHOD: We reviewed 62 cases (64 sides) of medial wall fractures that were treated surgically. They were diagnosed with 3 mm facial CT scans and treated according to the authors' indications from February 1998 to March 2004 at Namgwang Hospital, Seonam University. The surgical treatment consisted of the reconstruction of the fractures and the repair of the remaining bone defects by graft and splint, and the type of graft was selected according to the size of the defect. For minor defects, silastic sheet was used alone, whereas major defects were repaired with BOMF or Med-pore(R) registered. All patients were evaluated regularly for at least six months postoperatively. RESULTS: There were no differences in the aspects of the final treatment results of diplopia and enopthalmos. But in the aspects of postoperative crust formation and granulation, the cases that were repaired with BOMF showed better results as well as the economic merits. In the BOMF cases, the average duration of silastic sheet stenting was 12.5 days and it could reduce the follow up period. CONCLUSION: BOMF demonstrated better results in the respects of duration of silastic sheet stenting, postope-rative crust formation, granulation and economic cost.