Sinus cortical verticalization technique for atraumatic sinus lift: a case series with 18 months follow-up

Background. Crestal sinus lift is considered a predictable and increasingly used technique, with the aim of augmenting the bone quantity in the posterior-superior maxilla while reducing the invasiveness of implant-prosthetic regenerative treatment. The case series presented in this article analyzes a new minimally invasive technique introduced to limit the postoperative morbidity of crestal sinus floor elevation procedures, while managing an increasingly large number of clinical conditions.

Materials and methods. Forty-one implants were placed in the posterior maxilla of 33 patients using the proposed technique. The surgery duration, postoperative pain and discomfort reported by the patient, assessed using the NRS analogue scale with values between 0 and 10, and any complications were recorded. At 18 months after surgery, implant survival, the amount of vertical increase in regenerated hard tissue, the health status of the maxillary sinus were evaluated. Width and height of the residual alveolar process and vertical bone augmentation were assessed by radiology. The technique is based on the use of special rotating drills and bone condenser designed to make the surgical procedure faster, more efficient and predictable. The floor of the maxillary sinus is initially deformed, increasing the vertical dimension of the infrabony path of the implant site. Subsequently, a round portion of cortical is detached and repositioned apically, forming a roof over the graft and the inserted implant at the same time.

Results. The sites where this technique was applied showed an average residual bone height of 3.5 ± 1.2 mm while the length of the inserted implants was 8.5 mm and the diameter between 3.5 and 5 mm. Postoperative scores reported by patients on NRS scale from 0 to 10 showed an average for intraoperative pain of 0.6±0.8 and for perceived discomfort in the first week post-surgery a mean of 1.5±1.1. One case presented complications during surgery with a small tear in the sinus membrane, while only one case reported above-normal pain after surgery. Eighteen months after surgery, in all cases treated, newly formed mineralized tissue was appreciated around the implants inserted at the same time.

Conclusions. Limited to the cases treated, the proposed protocol appears to be an effective and predictable option for sinus elevation. Due to the deformation and subsequent apical displacement of the sinus floor, this technique has been shown to be effective in treating even wide sinus cases, with very limited residual bone height (1-3 mm), showing low postoperative morbidity.