It is administered as a stand-alone procedure in the hope that the tissue which obstructs the patient's airway is localized in the back of the throat.

Phase 2 involves maxillomandibular advancement, a surgery which moves the jaw top (maxilla) and bottom (mandible) forward.

If the procedure achieves the desired results, when the patient sleeps and the tongue relaxes, it will no longer be able to block the airway.

As explained above, sleep apnea is often caused by multiple co-existing obstructions at various locations of the airway such as the nasal cavity, and particularly the base of the tongue.

The contributing factors in the variability of success include the pre-surgical size of the tonsils, palate, uvula and tongue base.

Also, patients who are morbidly obese (body mass index >40 kg/m2) are significantly less likely to have success from this surgery.

Over one thousand people have undergone The Stanford Protocol operation and received follow-up sleep study testing.