Functional Outcome and Balance Compensation in Patients with Unilateral Vestibular Schwannoma After Surgical Treatment-Short- and Medium-Term Observation

Objective: The aim was to evaluate vestibular function in patients with unilateral vestibular schwannoma before and in the short and medium term after surgical treatment to analyze vestibular compensation. The identification of the prognostic factors determining incomplete and slower balance recovery was assessed. Methods: Forty-five patients with unilateral vestibular schwannoma treated surgically through the middle cranial fossa and translabyrinthine approach were enrolled in this study. The data were collected in the period between April 2022 and August 2023. The clinical data, vestibular tests (video head impulse test, sensory organization test) and the dizziness handicap inventory (DHI) before and after surgery were evaluated. Results: One month after surgery, a temporary deterioration in the DHI results occurred (DHI total score before surgery 24.36 vs. one month after surgery 31.64); however, a significant increase was found only by analyzing the functional subscale (p = 0.0395) for the DHI functional, emotional and physical subscale results; in addition, the total score before and three months after the surgery did not differ significantly. No statistically significant differences between the preoperative sensory organization test and the test one month after the surgery were found, while a significant improvement in the vestibular parameters was observed three months after the surgery compared to the preoperative results (C5 0.0306, C6 0.0002, VEST 0.0294, COMP 0.0023). A negative correlation was found between the DHI total score and C5 (-0.3198, -0.3266), C6 (-0.3448, -0.46379), VEST (-0.3100, -0.3252) and COMP (-0.4018, -0.4854) one and three months after the surgery, respectively. A significant deterioration was found between the LSC gain results on the tumor side (p < 0.001) and on the healthy side before the surgery vs. one month afterwards (p = 0.0079) and before the surgery vs. three months afterwards (p = 0.0419). The middle cranial fossa or translabyrinthine approach had no influence on the postoperative results. Conclusions: In the postoperative period, vestibular compensation occurs spontaneously. The results show that the functional level deteriorates one month after surgery but then improves significantly three months after the surgery, which confirms that compensation occurs gradually. The DHI functional subscale results before surgery and three months afterwards did not differ significantly, which demonstrates that functional recovery after vestibular denervation should take place within that time. In the present study, no predictive factors for unsatisfactory functional postoperative outcomes were found.