Maxillary sinus floor elevation surgery

Although augmentation of the maxillary sinus floor with autogenous bone grafts has become a well established preimplantology procedure, its effect on the function of the maxillary sinus has not been the subject of prospective human studies. In this prospective study the effects of sinus floor augmentation on maxillary sinus performance were evaluated. Seventeen consecutive patients who were to undergo augmentation of the maxillary sinus floor with an iliac crest autogenous bone graft agreed to participate in this study. All patients were subject to (i) extensive anamnestic and clinical investigation on sinusitis, (ii) conventional radiography (Waters’ projection) and (iii) unilateral endoscopic inspection of the maxillary sinus. This triad of evaluations was performed preoperatively, immediately preceding the augmentation procedure (the maxillary sinus to be inspected endoscopically was randomly selected), and at 3 (at insertion of the implants) and 9 months (at uncovering of implants) postaugmentation. None of the 17 patients showed clinical or radiological signs of actual sinus pathology preoperatively, though 5 patients had a history of an impeded sinus clearance. By contrast, unilateral endoscopic evaluation revealed preexisting subclinical mucosal pathology in two out of five patients with a history of sinus clearance impairment and in one out of the other 12 patients. At 3 months’ postaugmentation, clinical and radiographical examination showed chronic maxillary sinusitis in one non-compromised patient. Moreover, serial unilateral endoscopic evaluation revealed subclinical maxillary mucosal pathology in four other patients (two of whom had a history of an impeded sinus clearance), confirmed by Waters’ projection in three of these four patients. At 9 months’ postaugmentation, only subclinical maxillary mucosal pathology was detected endoscopically in two patients (one compromised, one non-compromised patient), confirmed by Waters’ projection in this last patient. Five implants were lost during the 9month observation period. As is obvious from this prospective evaluation, the effects of the augmentation procedure on maxillary sinus performance in patients without signs of maxillary sinusitis are of no clinical significance. Maxillary sinus floor elevation surgery with autogenous bone grafts has been proven to be a reliable preimplantology method to enable insertion of endosseous implants in a severely resorbed edentulous maxilla (Raghoebar et al. 2001). An often mentioned drawback of this procedure is the development of maxillary sinusitis after augmentation (Timmenga et al. 1997, 2001). Maxillary sinus floor elevation may involve the potential hazard of compromising the sinus physiology. After all, the maxillary physiology is affected by the alTimmenga et al . Aclinical, radiographic and endoscopic evaluation tered anatomic relation of the antral floor. In addition to the altered anatomy, mucosal injury and postoperative swelling may lead to reduction of the patency of the ostio-meatal unit, which plays a key role in the development of sinusitis, viz. impairment of the mucociliar cleansing system (Buiter 1976; Terrier 1991). If the patency of the maxillary ostium is reduced, or the maxillary sinus is (partly) filled up by postoperative hematoma or seroma, the development of a postoperative maxillary sinusitis may compromise the success of the sinus graft and/or implants and the patient’s sense of general physical well-being (Tos & Mogensen 1984; Melen et al. 1986; Dawes et al. 1989; Schow 1991; Stierna et al. 1991; Norlander et al. 1993; Nord 1995; Lanza & Kennedy 1997). The clinical diagnosis of sinusitis is characterized by a typical triad of symptoms, i.e. nasal congestion, pathological secretion or obstruction, and headache (Williams & Simel 1993; Yonkers 1995). Detection of postaugmentation maxillary sinusitis on conventional radiographs is difficult. Misinterpretation may easily occur, for example due to altered pneumatization and sinus depth as a result of the grafting procedure (Illum et al. 1972; Larenne et al. 1992; Wiltfang et al. 2000). Conversely, close inspection of the antral mucosa (the Schneiderian membrane) with fiber-endoscopic tools nowadays is the standard method in Ear, Nose and Throat (ENT) surgery and facilitates other diagnostic modalities such as histology, cytology and microbiology (Herberhold 1973; Buiter 1976; Howard & Lund 1986; Pfleiderer et al. 1986; Smith & Cable 1988; Kamel 1989; Terrier 1991; Bavbek et al. 1997; Bonifazi et al. 1997; Westergren et al. 1998). Direct observation of the ostiomeatal unit and antrum is beyond doubt of great importance in the evaluation of sinus (clearance) pathology and diagnosing maxillary sinusitis. The aim of this study was to prospectively evaluate the effects of maxillary sinus floor elevation surgery on maxillary sinus performance, applying anamnestic and clinical investigations, radiodiagnostic evaluation, and endoscopy. Material and methods