Measurement and comparison of postoperative anterior cord space between C2-7 and C3-7 laminoplasty on MRI

Abstract

To investigate the effect of C(2-7) laminoplasty on postoperative anterior cord space (ACS) compared with C(3-7) laminoplasty, and to provide evidence for reasonable enlargement of decompression range cephalad. Fifty-seven Patients underwent cervical laminoplasty from February 2008 to October 2011 were studied retrospectively, which were divided into two groups by decompression range: Group C(3-7) and Group C(2-7). The pre-and post operative JOA scores,VAS scores of neek and shoulder pain, and cervical alignment were compared in each group. The postoperative ACS at each level from C(2-3) to C(7)-T(1) measured on MRI were compared between the two groups. The postoperative JOA scores increased significantly in both groups. VAS scores and cervical alignment showed no significant difference. ACS at C(2-3) and C(3-4) was 6.13 mm (95%CI: 5.71-6.55) and 6.60 mm (95%CI: 6.10-7.11) respectively in Group C(3-7), which increased 2.5 mm and 2.1 mm respectively in Group C2-7 at the same segment, there was significant difference (P < 0.01). However, there was no significant difference of ACS at C(4-5) and any other caudal levels between the two groups. Compared with conventional C(3-7) laminoplasty, the extensive decompression cephalad to C(2) leads to larger ACS at C(2-3) and C(3-4). When the mid-sagittal diameter of anterior compression is more than 6.10 mm at C(3-4), C(3-7) laminoplasty may cause insufficient decompression, and enlargement of decompression range cephalad should be considered.