Effect of Platelet-Rich Fibrin on Neurosensory Recovery Following Bilateral Sagittal Split Osteotomy: A Randomized, Participant- and Assessor-Blinded, Split- Mouth Clinical Trial

When a surgeon reshapes the lower jaw to correct a bite or align the face, they perform a procedure known as a bilateral sagittal split osteotomy. This involves carefully splitting the jawbone to move the segments into a new position. While the surgery is routine and effective for fixing skeletal deformities, it carries a specific risk: the nerve that runs through the jawbone, which provides feeling to the lower lip and chin, can be bruised or stretched during the cut. When this happens, patients often wake up with numbness or a tingling sensation, a condition doctors call neurosensory disturbance. For many, this feeling fades away on its own as the nerve heals, but for others, the loss of sensation can linger for months or even become permanent. Because this nerve is so close to the cutting line, surgeons have long searched for ways to protect it or help it recover faster after the operation.

One promising avenue involves using the patient's own blood to create a healing aid. By spinning a small sample of a patient's blood in a centrifuge, doctors can separate out a thick, jelly-like substance rich in platelets, known as platelet-rich fibrin. This material acts like a natural scaffold, holding together a mix of growth factors and proteins that the body uses to repair tissues and reduce inflammation. Researchers have wondered if placing this substance directly onto the nerve during jaw surgery could act as a shield or a booster, helping the nerve recover more quickly than it would on its own. To find out, a team of researchers in Iran designed a study to test whether this simple addition made a measurable difference in how patients felt after their jaw surgery.

The study involved sixteen patients who were scheduled to undergo the jaw-splitting procedure to correct their bite. The researchers used a clever experimental design where each patient served as their own control. During the surgery, the surgeon applied the platelet-rich fibrin to the nerve on one side of the jaw but left the nerve on the other side untreated. This meant that every patient had a treated side and a control side, allowing for a direct comparison under identical conditions. Neither the patients nor the doctor who checked their feeling afterward knew which side had received the treatment, ensuring that the results were based on physical recovery rather than expectation. The team then tested the patients' sensation at three months and again at six months after the operation.

The tests were straightforward and focused on how well the patients could feel their lower lip and chin. They were asked to identify the direction a brush was moving across their skin, to feel the difference between one point and two points of pressure, and to detect a cold spray. They also rated their own level of numbness on a scale from zero to ten. The results showed a clear advantage for the side that received the platelet-rich fibrin. At the three-month mark, the treated sides performed significantly better on the brush test and could distinguish two points of pressure at a much closer distance than the untreated sides. Patients also reported feeling much less numbness on the treated side, with an average score of three out of ten, compared to nearly five out of ten on the untreated side.

By the six-month follow-up, the treated sides continued to show superior results. The ability to distinguish two points of pressure remained significantly better on the side with the platelet-rich fibrin, and patients still reported significantly less numbness. The cold sensitivity test showed a similar pattern, with the treated side detecting the cold stimulus more often at three months, though this difference had faded by the six-month mark. The data suggests that the platelet-rich fibrin did not necessarily change the final outcome for everyone, but rather sped up the healing process. The untreated sides were also recovering, but the treated sides were ahead of the curve, showing that the body's natural repair mechanisms were working more efficiently when supported by the fibrin.

The researchers concluded that applying this blood-derived material during the surgery is associated with a faster and more complete recovery of sensation in the early months following the procedure. However, they noted that the study was limited to a six-month window, so it remains unclear if this early boost leads to a permanent difference in sensation years down the line. The study did not find any negative side effects from using the material, and no patients had to stop the treatment. While the findings are encouraging, the authors emphasize that larger studies with longer follow-up periods are needed to confirm whether this approach can prevent long-term numbness or if its primary benefit is simply helping patients feel normal again sooner. For now, the evidence points to a promising, low-risk method to support nerve healing in a complex surgery where feeling is often the first thing to go and the last thing to return.