How are the degrees of inferior alveolar nerve injury differentiated after Bilateral Sagittal Split Osteotomy (BSSO)?

BSSO (Benign Prostatic Hyperplasia), one of the most common surgical techniques, involves longitudinally splitting the bone to advance or retract the lower jaw, and the inferior alveolar nerve passes directly through this line. Postoperative sensory loss in the lower lip and chin is classified into three groups based on the degree of nerve damage: “Neuropraxia,” the mildest form where the nerve is not severed but temporarily interrupted due to stretching or compression, usually resolving completely within a few weeks; “Axonotmesis,” where the nerve fibers (axons) are damaged but the sheath surrounding the nerve remains intact, with healing taking 6-12 months; and “Neurotmesis,” the most severe condition where the nerve is completely severed, resulting in permanent numbness without microsurgical intervention. Surgeons perform risk analysis using preoperative three-dimensional CT scans (CBCT) to determine the nerve’s trajectory with millimeter precision.