A different Sinus Approach, lateral and Internal Sinus Access (LISA)- a New Hybrid Technique

Access to the sinus cavity for bone augmentation-both lateral window approach, and internal or crestal approach - are challenged by many complications, most commonly tear of the Schneiderian membrane.

A technique was developed where crestal approach, a blind technique by nature, is augmented with a small lateral window that verifies proper lift, and separation of the membrane.

The LISA technique utilizes specially designed piezoelectric surgery device tips to prepare lateral and internal sinus access. The tips were originally developed and used in a technique known as hydrodynamic piezoelectric internal sinus elevation (HPISE, Sohn et al 2010).

Although HPISE has been received well by many clinicians globally, it is still a blind technique, and may still produce the inadvertent membrane tear. The LISA technique adds one or more small (3.5 mm in diameter) lateral window immediately superior to the anticipated implant position.

This is opened prior to the crestal approach using either LISA rotary bur or piezoelectric surgery tip (Sohn 028). The surgically exposed membrane through lateral approach lessens the membrane tension, which can be extended to floor of the sinus region through hydrodynamic effect of the Sohn tips.

This relaxation may be enhanced with miniature sinus curettes. Both the relaxation of membrane and visual confirmation allows the next step of internal approach to be much more predictable. This step through the alveolar crest uses either the same piezoelectric tip or with rotary instruments.

A composite graft of platelet-rich fibrin and mineralized allograft or xenograft is then packed through both the internal and lateral access holes. Concurrent implant placement is possible with this approach.