One Piece Orbitozygomatic Approach Based on the Sphenoid Ridge Keyhole: Anatomical Study

Anatomical features of the sphenoid ridge in the pediatric population

PURPOSE

To describe the relation of the sphenoid ridge (SR) with the surrounding anatomical structures in healthy children when approaching the anterior and middle fossae.

METHODS

Computed tomography of 180 pediatric patients (90 males / 90 females), aged 1-18 years were included the study. The size of the lesser wing (LW) and the distances of the LW to certain landmarks were measured.

RESULTS

The LW length was 28.48 ± 8.15 mm. The LW widths at the midline and the midpoint and lateral point of the SR were 7.78 ± 1.74 mm, 2.84 ± 0.81 mm, and 1.91 ± 0.64 mm, respectively. The distance between the midpoint of the SR and the crista galli was 28.22 ± 5.56 mm, and the distance between the crista alaris and internal auditory meatus was 51.73 ± 5.79 mm. The linear function was calculated as y = 18.748 + 1.024 × age for SR length, y = 6.046 + 0.182 × age for the midline width of SR, y = 2.367 + 0.050 × age for the midpoint width of SR, y = 1.249 + 0.069 × age for the crista alaris width, y = 21.727 + 0.683 × age for the distance between the SR midpoint and the crista galli, and y = 43.614 + 0.855 × age for the distance between the crista alaris and internal auditory meatus.

CONCLUSION

All measured parameters increased irregularly with advancing age. Furthermore, our regression equations representing the growth dynamics of SR may be used to estimate these parameters.

Pure Endoscopic Lateral Orbitotomy Approach to the Cavernous Sinus, Posterior, and Infratemporal Fossae: Anatomic Study

Objective  The aim of this anatomic study is to describe a fully endoscopic lateral orbitotomy extradural approach to the cavernous sinus, posterior, and infratemporal fossae. Material and Methods  Three prefixed latex-injected head specimens (six orbital exposures) were used in the study. Before and after dissection, a computed tomography scan was performed on each cadaver head and a neuronavigation system was used to guide the approach. The extent of bone removal and the area of exposure of the targeted corridor were evaluated with the aid of OsiriX software (Pixmeo, Bernex, Switzerland). Results  The lateral orbital approach offers four main endoscopic extradural routes: the anteromedial, posteromedial, posterior, and inferior. The anteromedial route allows a direct route to the optic canal by removal of the anterior clinoid process, whereas the posteromedial route allows for exposure of the lateral wall of the cavernous sinus. The posterior route is targeted to Meckel's cave and provides access to the posterior cranial fossa by exposure and drilling of the petrous apex, whereas the inferior route gives access to the pterygopalatine and infratemporal fossae by drilling the floor of the middle cranial fossa and the bone between the second and third branches of the trigeminal nerve. Conclusion  The lateral orbitotomy endoscopic approach provides direct access to the cavernous sinus, posterior, and infratemporal fossae. Advantages of the approach include a favorable angle of attack, minimal brain retraction, and the possibility of dissection within the two dural layers of the cavernous sinus without entering its neurovascular compartment.