To allow functional access to the superior orbits and/or nasal region, it is necessary to release the supraorbital neurovascular bundle from its notch or foramen. This maneuver involves dissecting in the subperiosteal plane completely around the bundle, including inside the orbit. If no bone is noted inferior to the bundle, the bundle can be gently removed from the bony bridge along the supraorbital rim to release the bundle (Fig. 6-17).
Figure 6-17 Technique of removing bone inferior to the supraorbital foramen (when present) so the neurovascular bundle can be released. Relaxing incisions in the sagital plane through the elevated periosteum over the bridge of the nose are also shown. Use of this technique greatly facilitates dissection more inferiorly along the nasal dorsum.
Further retraction of the flap inferiorly may be accomplished by subperiosteal dissection into the orbits. The orbital contents attached to the lateral orbital tubercle are stripped, allowing dissection deep into the lateral orbit. Release of the periosteum around the inferior rim of the orbit allows exposure of the entire orbital floor and infraorbital region. Access to the infraorbital area is easiest after overlying tissue of the zygomatic arch and body are released to relax the overlying envelope.
Dissection of the periosteum from the superior and medial orbital walls releases the flap and allows retraction down to the level of the junction of the nasal bones and upper lateral cartilages. This technique is facilitated by carefully incising the periosteum of the nasofrontal region (see Fig. 6-17). Dissection can proceed along the dorsum to the nasal tip, if necessary (Fig. 6-18).
The medial canthal tendons should not be inadvertently stripped from their attachments to the posterior and anterior lacrimal crest. They are identified as dense fibrous attachments in the nasolacrimal fossa (Fig. 6-19). The entire medial orbital wall may be exposed without stripping the canthal tendons. As subperiosteal dissection proceeds posteriorly along the medial orbital wall, the surgeon should be on the lookout for the anterior (and posterior) ethmoidal artery. A simple method to identify and cauterize the artery is to strip the periosteum along the roof of the orbit and inferior to where the artery pierces the medial orbital wall. With a periosteal elevator on each side of the foramen, retraction allows the periosteum attached to the foramen to "tent" outward (Fig. 6-20). Bipolar cauterization of the artery may be performed, followed by transection. Dissection can then proceed posteriorly by subperiosteal elevation.
After the dissections just described, the upper and middle facial regions are completely exposed (Fig. 6-21). The entire orbit can be dissected from the orbital rims to the apex; the only remaining structure is the medial canthal tendon, unless it was intentionally or inadvertently stripped._
Figure 6-21 Amount of exposure obtained with complete dissection of the upper and middle facial bones using the coronal approach. Note maintenance of attachment of the medial canthal tendon. The infraorbital areas are also exposed if retraction is performed from the side of the orbit.
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