Volumetric Changes in Cervical Disc Herniation: Comparison of Cervical Expansive Open-door Laminoplasty and Cervical Microendoscopic Laminoplasty.

STUDY DESIGN: Retrospective study on 185 patients with 490 cervical disc herniation (CDH).

OBJECTIVE: The aim of this study was to compare the changes in volumes of CDH in patients with degenerative cervical myelopathy (DCM) surgically treated by expansive open-door laminoplasty (EOLP) or cervical microendoscopic laminoplasty (CMEL).

SUMMARY OF BACKGROUND DATA: Spontaneous resorption of CDH was shown in patients with DCM after conservation treatment, but very few in surgically treated patients. Our previous study identified the clinical efficiency of CMEL to treat DCM but how CDH sized postoperatively, as well as comparing to EOLP, was unknown.

METHODS: Consecutive patients with DCM from December 2015 to December 2019, who underwent MRI evaluation, receiving CMEL or EOLP, and repeat MRI in follow-up were included. The volume of CDH were monitored using the picture archiving and communication system, further calculating the incidence of CDH with volume regression and the percentage changes of CDH volume. The correlations of possible determines with CDH volume changes were analyzed by Spearman rank correlation coefficient.

RESULTS: A total of 89 patients (215 CDHs, EOLP-group) and 96 patients (275 CDHs, CMEL-group) was surveyed, respectively. Resultantly, volume of CDH was decreased postoperatively in both EOLP and CMEL cases. But this CDH volume regression was more profound in CMEL groups (incidence of 81.2% from 223/275, median volume change ratio of -26.7%, occurring from 1 month after CMEL), statistically different from EOLP group (50.2% from 108/215, median volume change ratio of -5.4%, none-appearance within 1 month). Patients information as sex, age, and follow-up time, not CDH significant, was significantly correlated with CDH volume changes.

CONCLUSION: Patients who underwent CMEL developed a postoperative reduction of CDH volume, with more popularity, greater degree and earlier-staged than EOLP-patients. Young females with longer follow-up time were more likely occur.Level of Evidence: 4.