Objective
Hoarseness can occur after spinal surgery under general anesthesia, which has been assessed through self-report measures based on questionnaires. Given the inherent biases associated with self-report instruments, there is a need for more objective measures to assess hoarseness.
Methods
Single institute, a prospective observational study was planned to include 427 patients after spine surgery. This interim analysis was planned to include 215 patients who met the inclusion criteria. All subjects included in this study submitted a questionnaire of Korean Voice Handicap Index (KVHI)-10. Voice analysis including low or high pitch (Herz), frequency variation rate (jitter), amplitude variation rate (Shimmer), and noise-to-harmonic ratio (NHR) was performed with a software of Pratt.
Results
This interim report enrolled a total of 215 patients who met the inclusion criteria, and among them, 162 patients (75.5%) were subjected to interim analysis after excluding those with data loss (8 patients), operation cancellation (3 patients), and loss to follow-up (42 patients). The incidence of hoarseness was 35.0% on postoperative day (POD)0 and 5.5% on POD30. In the acoustic parameters analyzed, hertz and jitter were significantly positively correlated with the KVHI-10 scores on POD0, while only the jitter value significantly correlated with POD30. The optimal cutoff values of the acoustic parameter on POD30 from the receiver operating characteristic curve were 0.65% in jitter, 4.67% in shimmer, and 16.96 dB in NHR.
Conclusion
This study revealed a correlation between objective acoustic parameters obtained from voice analysis and subjective questionnaire scores for hoarseness.

Objective
Motor-evoked potential (MEP) loss during intramedullary (IM) spinal cord tumor surgery impairs the ability to monitor further neural injury. Direct wave (D-wave) monitoring may allow continued assessment of corticospinal tract integrity after MEP loss. This study evaluates the role of D-wave-guided surgery in preserving function and enabling safe resection after MEP loss.
Methods
A retrospective study was conducted in adult patients with ependymoma (EPN), cavernous angioma (CA) or subependymoma who experienced MEP loss during IM tumor resection between January 2012 and May 2025. Patients who underwent continued resection under D-wave guidance after MEP loss were compared with those who did not.
Results
Among 37 eligible patients, 9 underwent D-wave-guided surgery and 28 did not. Functional improvement at the last follow-up was more frequent in the D-wave-guided surgery group (66.7% vs. 17.9%, p=0.011). This trend remained significant in EPN patients (74.4% vs. 9.1%, p=0.003), but not in CA patients. Immediate postoperative motor grade ≤3 was more common in the D-wave-guided surgery group (66.7% vs. 39.3%), although this difference was not statistically significant (p=0.251). By last follow-up, the proportions of patients self-ambulatory without external aids (88.9% vs. 89.3%, p=1.000) were similar between groups. Extent of resection, complications, and recurrence rates showed no significant differences.
Conclusion
D-wave-guided surgery may enable safe continuation of tumor resection after MEP loss without increasing morbidity. It offers a viable intraoperative strategy to preserve long-term motor function by extending monitoring beyond MEP limitations.

Objective
Chordoma, a rare malignant tumor originating from embryonal notochord remnants, exhibits high resistance to conventional treatments, making surgical resection imperative. However, the factors influencing prognosis specifically for cervical spine chordoma have not been clearly identified. We investigate the prognosis of cervical spine chordoma with factors influential in a nationwide multicenter retrospective study.
Methods
This study included all patients diagnosed with cervical spine chordoma at 7 tertiary referral centers from January 1998 to March 2023, excluding those with clivus and thoracic spine chordomas extending into the cervical spine. Local recurrence (LR) was identified through follow-up magnetic resonance imaging, either as reappearance in completely resected tumors or regrowth in residual tumors. The study assessed LR and overall survival, analyzing factors influencing LR and death.
Results
Forty-five patients with cervical spine chordoma had a mean age of 46.4 years. Over a median follow-up of 52 months, LR and distant metastasis were observed in 21 (46.7%) and 4 patients (8.9%), respectively, and 16 patients (36%) were confirmed dead. The 5-year and 10-year cumulative LR rates were 51.3% and 60%, respectively, while the 5-year and 10-year survival rates were 82% and 53%. Age was the only significant factor affecting mortality (hazard ratio, 1.04; 95% confidence interval, 1.04–1.07; p=0.015). Notably, the degree of resection and adjuvant therapy did not statistically significantly impact local tumor control and mortality.
Conclusion
This study, the largest multicenter retrospective analysis of cervical spine chordoma in Korea, identified age as the only factor significantly affecting patient survival.