Neurophysiological Evaluation of the Facial Nerve in Parry-Romberg Syndrome: A Proposed Preoperative Protocol Before Nerve Transfer

Parry-Romberg syndrome (PRS) is a rare disorder of unknown etiology characterized by unilateral atrophy of facial subcutaneous and deep tissues. Although the trigeminal and facial nerves may be involved, evidence is limited, and neurophysiological abnormalities are not routinely incorporated into presurgical evaluation. This study aimed to describe clinical and neurophysiological findings in these nerves among adults with unilateral PRS previously treated with autologous fat grafting alone. A cross-sectional descriptive study included 10 adults with unilateral PRS who underwent clinical examination, facial nerve neurography, electromyography, and blink reflex testing. Disease severity was classified using the Guerrerosantos scale. Eight participants (80%) were women; mean age was 30.8 ± 14.4 years. Facial neurography showed axonal degeneration in 7 of the patients (70%), while all demonstrated a chronic neuropathic EMG pattern. Guerrerosantos types 1 and 2 were most frequent (30% each). Blink reflexes on the affected side were normal in eight patients (80%) and abnormal in two (20%). Trigeminal motor and sensory function were preserved in most patients. These findings confirm predominant chronic facial nerve axonal degeneration with largely preserved trigeminal function. Preoperative neurophysiological assessment of facial nerve viability should be considered when planning dynamic reconstruction, including nerve transfer.