ORBITAL MORPHOLOGY WITH REFERENCE TO BONY LANDMARKS. 20 La morfología de la órbita en relación a los parámetros óseos

Las órbitas óseas son cavidades del esqueleto situadas a cada lado de la nariz. Se conocen las diferencias raciales en las medidas orbitales. El objetivo del presente estudio era determinar las distancias de varias fisuras y foramen en la órbita en relación a ciertos puntos de referencia óseos / quirúrgicos sobre los márgenes orbitales en la población india, lo que puede ser útil durante la cirugía orbital. La distancia de canal óptico (OC), fisura orbitaria superior (SOF), fisura orbital inferior (IOF) y forámenes lagrimales (LF) se mide a partir de puntos de referencia como cresta lacrimal anterior (ALC) para la pared medial, muesca/foramen supra orbital (SN) para la pared superior, sutura cigomática frontal (FZ) de la pared lateral y un punto en el margen inferior (OIM) justo encima del agujero infraorbitario. Se midió la distancia del foramen etmoidal anterior y posterior (AEF y PEF) de ALC. Se observó la presencia de foramen etmoidal media (MEF) y forámenes lagrimales (LF).La distancia media de OC fue 39,71 ±2,67 mm(deALC), 45,11 ±3,4 mm(de SN) , 48,32 ±2,8 mm(de FZ ) y 45,97 ±3,9 mm(de OIM). La distancia segura para el nervio óptico para cada pared orbital se calcula restando5 mmde la distancia más corta medida. The bony orbits are skeletal cavities located on either side of the nose. Racial differences in orbital measurements are known. The aim of the present study was to determine the distances of various fissures and foramen in the orbit with reference to certain bony / surgical landmarks on the orbital margins in Indian population which can be useful during various surgical procedures. The distance of optic canal (OC), superior orbital fissure (SOF), inferior orbital fissure (IOF), lacrimal foramen (LF) were measured from landmarks like anterior lacrimal crest (ALC) for medial wall, supraorbital foramen/ notch (SON) for superior wall, fronto-zygomatic suture (FZ) for lateral wall and a point on inferior margin (IOM) just above the infraorbital foramen. Distance of anterior and posterior ethmoidal foramen (AEF and PEF) from ALC was measured. The incidence of middle ethmoidal foramen (MEF) and lacrimal foramen (LF) was noted. The mean distance of OC was 39.71 ±2.67 mm(from ALC), 45.11 ±3.4 mm(from SN), 45.97 ±3.9 mm(from FZ) and 48.32 ±2.8 mm(from IOM). The safe distance for optic nerve for each orbital wall was derived by subtracting5 mmfrom the shortest measured distance.

Transorbital Endoscopic Identification of Supernumerary Ethmoid Arteries

Background Anterior and posterior ethmoid arteries supply the paranasal sinuses, septum, and lateral nasal wall. Precise identification of these arteries is important during anterior skull base procedures, endoscopic sinus surgery, and ligation of ethmoid arteries for epistaxis refractory to standard treatment. There is controversy in the literature regarding the prevalence of supernumerary ethmoid arteries. Objective This study examined the prevalence of supernumerary ethmoid arteries by using direct visualization after transorbital endoscopic dissection. Methods Nineteen cadaveric specimens were evaluated by using a superior lid crease (blepharoplasty) incision and an endoscopic approach to the medial orbital wall. Ethmoid arteries were identified as they pierced the lamina papyracea coplanar with the skull base and optic nerve. The distances from the anterior lacrimal crest to the ethmoid arteries and optic nerve were measured with a surgical ruler under endoscopic guidance. Results Thirty-eight cadaveric orbits were measured. Overall, there were three or more ethmoid arteries (including anterior and posterior arteries) in 58% of orbits, with 8% of the total sample that contained four or more ethmoid arteries. The average number of ethmoid arteries was 2.7. Bilateral supernumerary ethmoid arteries were noted in 42% of the specimens. The distance between the anterior lacrimal crest and the anterior ethmoid, posterior ethmoid, and optic nerve averaged 20, 35, and 41 mm, respectively. The average distance to the supernumerary or middle ethmoid artery was 29 mm. Conclusion This study found supernumerary ethmoid arteries in 58% of cadaveric specimens, a prevalence much higher than previously reported. Recognition of these additional vessels may improve safety during endoscopic sinus surgery and skull base surgery, and may permit more effective ligation for refractory epistaxis originating from the ethmoid system.

Surgical Anatomy of the Orbit

When operating in and around the orbit, the key to a successful operative result is precise, anatomic localization. This study was constructed to give pertinent anatomic measurements to which the maxillofacial surgeon may refer. The safe distances noted from this study are: 1) medially 30 mm from the anterior lacrimal crest; 2) inferiorly 25 mm from the infraorbital foramen; 3) superiorly 30 mm from the supraorbital notch; and 4) laterally 25 mm from the frontozygomatic suture.

Dacryocystorhinostomy Utilizing an Anterior Lacrimal Sac Flap to Periosteum Technique

Dacryocystorhinostomy is used in the effective treatment of epiphora secondary to obstruction of the lacrimal drainage system. Common causes of obstruction include canalicular disruption, lacrimal sac fibrosis, and external and internal nasal trauma. Most techniques of dacryocystorhinostomy attempt to suture the lacrimal sac mucosa to the nasal mucosa. At best this is technically difficult, and the mucosa frequently tears. A technique is presented using an anteriorly based lacrimal sac pedicle flap sutured to the periosteum of the anterior lacrimal crest. The sutured flap is quite strong, and the procedure is technically simpler than others. A brief description of the causes of lacrimal obstruction is given. The Jones primary and secondary dye tests for lacrimal system patency are reviewed.