for people ages up to 45 years (full criteria)
Healthy Volunteers
healthy people welcome
at San Francisco, California and other locations
study started
estimated completion
Principal Investigator
by Sohail Saghezchi, DDS, MD



The aim of this prospective study is to analyze the postoperative paresthesias experienced in patients who undergo bilateral sagittal split osteotomies (BSSO) using an ultrasonic saw, versus a reciprocating saw. Patients included in the study are ages 15-45 scheduled to undergo BSSO surgery at the University of California, San Francisco. One side of the patient's mandible will be instrumented with either the Stryker Sonopet ultrasonic saw or traditional reciprocating saw, while the other side will receive the remaining intervention (determined via randomization on the day of surgery). Patient paresthesias will then be analyzed on each side for 3 months postoperatively (at postoperative days: 1, 7, 14, 28, and 84). Sensory examinations will be carried out by blinded examiners using von Frey hairs and two point discrimination testing. Patients will also subjectively rate their sensation on each side. The results will then be analyzed to determine if patient paresthesias, including the severity and duration, differed depending on which instrument was used, the ultrasonic or reciprocating saw.

Official Title

In-person Randomized Control Trial of the Incidence of Postoperative Hypoesthesia Among Bilateral Sagittal Split Osteotomy Patients Treated With Ultrasonic vs. Reciprocating Saw Instrumentation


Surgical Complication, Paresthesia, Fracture, Nerve Injury, Nerve Entrapments, Mandibular Nerve Injuries, Mandibular Hypoplasia, Mandibular Retrognathism, Mandibular Hyperplasia, Mandibular Prognathism, BSSO, Bilateral Saggital Split Osteotomy, Unfavorable split, Unfavorable fracture, Inferior Alveolar Nerve, Reciprocating Saw, Ultrasonic Saw, Pair matched, Randomized Control Trial, Retrognathia, Prognathism, Micrognathism, Angle Class III Malocclusion, Nerve Compression Syndromes, Hyperplasia, Wounds and Injuries, Sonopet ultrasonic saw


You can join if…

Open to people ages up to 45 years

  • Must be undergoing bilateral sagittal split osteotomy surgery with Dr. Saghezchi at UCSF
  • Must agree to return for all follow up visits.
  • Must not have any preexisting V3 nerve paresthesia
  • Must be below the age of 45.

You CAN'T join if...

  • Persons with preexisting V3 nerve paresthesias
  • Pre-pubertal children will be excluded (per routine practice for this type of surgery).
  • Patients with syndromic genetic conditions that demonstrate clearly different anatomy in the two sides of their jaws will be excluded since the two sides may not be "exchangeable".


  • UCSF Medical Center
    San Francisco California 94143 United States
  • UCSF Benioff Children's Hospital
    San Francisco California 94158 United States

Lead Scientist at UCSF

  • Sohail Saghezchi, DDS, MD
    Associate Professor, Oral & Maxillofacial Surgery, School of Dentistry. Authored (or co-authored) 4 research publications


accepting new patients by invitation only
Start Date
Completion Date
University of California, San Francisco
Study Type
Expecting 50 study participants
Last Updated