Application of Piezosurgery in En Bloc Laminectomy for the Treatment of Multilevel Thoracic Ossification of Ligamentum Flavum

OBJECTIVE: To evaluate safety and effectiveness of the application of piezosurgery in en bloc laminectomy for the treatment of multilevel thoracic ossification of ligamentum flavum (MTOLF). METHODS: Forty-one cases who had MTOLF and underwent en bloc laminectomy from January 2012 to January 2017 were reviewed and divided into Group A (high-speed drill, n = 23) and Group B (piezosurgery, n = 18). Comparisons in clinical outcome and perioperative complications were carried out between the 2 groups. RESULTS: Mean follow-up period was comparable between Group A (12.6 months) and Group B (11.4 months). Both operation time and intraoperative blood loss in Group A were significantly more than those in Group B (P < 0). Although final Japanese Orthopaedic Association (JOA) score in both groups significantly increased, differences in preoperative JOA, final JOA, and neurologic recovery rate between the 2 groups weren't significant. Perioperative complications included early neurologic deterioration (1 in Group A), wound infection (2 in Group A and 1 in Group B), and leakage of cerebrospinal fluid (5 in Group A and 1 in Group B); incidences of these complications between the 2 groups weren't significant (P > 0.05). A relationship analysis showed that cases with preoperative tram track sign, tuberous OLF, or larger compression ratio were at greater risk of developing an intraoperative dura defect. CONCLUSIONS: The application of piezosurgery in en bloc laminectomy is a safe and effective method in the treatment of MTOLF, and it was advantageous for reducing both operation time and intraoperative blood loss compared with the high-speed drill.