Complications and Outcomes of Sinus Augmentation Procedures Using the Lateral Window Approach

Sinus floor augmentation is a widely performed and highly predictable procedure for reconstructing the resorbed atrophic edentulous ridge of the posterior maxilla and restoring function by means of endosseous implants.¹ Currently, the lateral window approach is considered to be the gold standard approach to increase the height and width of the available bone in the posterior maxilla.²There are, however, potential complications associated with this approach that would be expected, like any other surgical procedure. The objective of this study was to investigate the prevalence of different complications, the impact of these complications on ongoing implant treatment, and the outcomes of sinus augmentations in a patient population with pneumatized maxillary sinuses and reduced alveolar bone.

Sixty-seven consecutive patients (33 female and 34 male), aged 32 to 78 years (mean age 55 years), requiring maxillary sinus augmentation for simultaneous or delayed placement of implants were included. Thirty-seven patients were operated on unilaterally and 29 bilaterally. All sinuses were approached through the lateral window technique. Sixty-three patients received allograft, 3 patients received autograft and 1 patient received alloplast. Four patients required unilateral sinus reoperation. A total of 128 implants were installed, 63 simultaneously and 65 in a second stage. A minimum of 5 mm of alveolar bone height remaining was required for considering simultaneous implants placement. 

The sample size was 67 patients, who received sinus augmentation surgery and 128 implants. Patients were chosen retrospectively, and were evaluated and analyzed at a minimum of 12 months postoperatively. Descriptive and quantitative analyses were performed. Success and failure rates of implants placed simultaneously and non-simultaneously were compared and analyzed by a chi square test using SPSS software ver 16 (level of significance = 0.003).

A total of 99 sinus augmentation procedures were performed. In 13 (13%) of the 99 sinuses the sinus membrane was perforated accidentally during surgery. Three patients (4.5%) developed postoperative maxillary sinusitis. One of these patients had had a perioperative sinus membrane perforation. Two patients (3%) suffered perioperative hemorrhages during the approach, which reduced visualization of the window preparation. One patient (1.5%) had a local wound dehiscence, and 3 patients (4.5%) developed postoperative graft infections and loss of graft. Out of 128 implants 114 implants (89%) integrated successfully and 14 implants (11%) failed: 12 (9.38%) placed simultaneously and 2 (1.56%) placed in a second stage surgery, all before loading. There was a statistical difference between the losses of implants placed simultaneously versus non-simultaneously (p=0.003). Two of the failed implants were replaced with wider implants in the grafted areas and received prosthesis as well, for an overall post loading success rate of 90%. Follow-up for all patients after final restoration was between 12 and 120 months.

The lateral window approach for maxillary sinus augmentation is associated with a good rate of success. Certain complications may arise during the procedure that may influence the outcome of clinical treatment. In this study, simultaneous placement of implants during direct sinus augmentation appeared to significantly affect their chance of success.

1. Raja SV. Management of the posterior maxilla with sinus lift: review of techniques. J Oral Maxillofac Surg. 2009 Aug; 67(8): 1730-4.

2. Simon BI, Greenfield JL. Alternative to the gold standard for sinus augmentation: osteotome sinus elevation. Quintessence Int. 2011 Nov-Dec; 42(10): 863-71.