Abstract
Major problems associated with the use of a bone lid for osteoplastic surgery of the maxillary sinus, as first described by Lindorf, are the possibility of postoperative dislocation of the bony fragment into the sinus (floating bone), as well as inflammatory resorption or fracture of the very thin removed trap door fragment. We describe a technique that prevents dislocation of the bone lid and allows for very good visualization of the entire sinus by a simple extended design and the use of resorbable pins. With the use of this extended bone lid, the removal of severely dislocated teeth, implants, sinus pathologies, or foreign bodies can be performed easily. Furthermore, this is an advantageous approach for large orbital fractures, especially those of the posterior half.
More than 100 years ago, Caldwell and Luc described the approach to the maxillary sinus via trephination of its thin anterior wall. To prevent chronic pain due to scarring of the sinus membrane, Lindorf described a new technique for use in place of the conventional Caldwell–Luc approach, involving the creation of a bone lid; this approach allowed for replantation of the bone lid after the procedure. Feldmann modified this technique by fixing the osseous lid with sutures in its corners. Since then, various modifications of the technique have been described using the Schneiderian membrane in the superior osteotomy line as a vascularized pedicle.
Major problems of these techniques include the possibility of postoperative dislocation of the bony fragment into the sinus (floating bone), as well as inflammatory resorption or fracture of the very thin removed trap door fragment. We therefore describe a technique that prevents dislocation of the bone lid and allows for very good visualization of the entire sinus by a simple extended design and the use of resorbable pins. With the use of this extended bone lid, the removal of severely dislocated teeth, implants, sinus pathologies, or foreign bodies can be performed easily. Furthermore, this is an advantageous approach for large orbital fractures, especially those of the posterior half.
Methods
To allow for good visualization of the maxillary sinus, as well as safe pinning of the bony trap door, the osteotomy lines are extended into the body of the zygomatic bone and into the paranasal apical canine region (see Fig. 1 ). Sufficient cancellous bone for later refixation of the bone lid can be found in these areas ( Fig. 1 A and C). Before performing the osteotomy, the infraorbital nerve and the dental roots must be identified to avoid injury or damage during the procedure. Following this, the horizontal cuts and the medial vertical cut are easily done using an ultrasonic surgery device (Piezotome) or a fissure bur ( Fig. 1 B and D). The dorsal cut in the zygomatico-alveolar crest is simply done using an angulated Piezotome, a thin fissure bur, or a wheel saw ( Fig. 1 E). The osteotomy lines should not be completed with the Piezotome or bur in the craniolateral or caudomedial corner. The crucial step of this technique is the osteotomy using a chisel to gently break the bone at its cancellous pedicles ( Fig. 1 A and C).
This type of window design creates a large access and allows good visualization of the maxillary sinus ( Fig. 2 ). Since the outer regions of this fragment are made of thicker bone, it appears as a bony frame with a thin cortical wall in the middle. This cancellous lid is very stable and can be replaced and fixed easily with screws or absorbable pins in the craniolateral and caudomedial corners (see Fig. 3 ); this is in contrast to the conventional Lindorf bone lid, which can easily break in its corners during fixation.
