Clinical and radiological outcomes following open door laminoplasty: a single center evolution of the technique

Background: A comparison of clinical and radiological outcomes after two different variants of open door laminoplasty for cervical spondylotic myelopathy (CSM) is described. Methods: Fifty-five patients underwent cervical laminoplasty for CSM. Between 2005 to 2009, 32 patients underwent open-door laminoplasty (Group A) performed with a monolateral exposure with contralateral "green stick" laminar fracture. A technical variant consisting in bilateral exposure, spinous process removal and symmetrical muscular closure was applied in the other 23 (Group B), from 2009 to 2016. A retrospective analysis of surgical results between the two groups was performed. Results: In group B, the mean operative time was longer and the mean volume of intraoperative blood loss was much higher than in group A. Both differences were not significant (p=0.1601 and p=0.0884, respectively). The average hospitalization was nonsignificantly longer in group B (7.3±1.8 vs. 6.5±1.6 d; p= 0.0947). Postoperatively, axial neck pain was more severe in group A at last follow-up than preoperatively (P>0.05). mJOA scores and Nurick grades improved significantly in both groups at last follow-up; in group A, the mean recovery rates were 41.5 % by mJOA scores and 29.4 % by Nurick grades, whereas in group B they were 52.7 % and 36.8 %, respectively. Conclusions: Applying some few variations to a standard monolateral approach, although slightly more time and blood consuming, could reduce the incidence of long term axial symptoms and, in our experience, are not burdened by worsening of outcomes. A prospective, multicentric study with a longer follow-up should be conducted in order to confirm our findings.