Imaging study of mesh placement on the postoperative effects of hybrid decompression and fixation for 3-level cervical spondylotic myelopathy

English Keywords:Cervical spondylotic myelopathy  3－level  Hybrid decompression and fusion  Internal fixation  Titanium mesh subsidence

English Abstract:

  【Abstract】 Objectives: To explore the location effects of mesh placement on postoperative subsidence in patients with 3-level cervical spondylotic myelopathy undergone hybrid decompression and fusion(HDF). Methods: 58 cases with 3-level cervical spondylotic myelopathy undergone HDF from September 2016 to September 2020 admitted to the spinal surgery department of our hospital were divided into group A(titanium mesh located at the cephalad end, n=32) and group B(titanium mesh located at the caudal end n=26). The general conditions(gender, age, course of disease, operative segment, operative time, intraoperative bleeding, and postoperative follow-up time) of the patients in the two groups were collected. The imaging data of intervertebral height of mesh located segment, fused segment Cobb angle, and C2-7 Cobb angle before surgery on the day right after surgery, at 2 months after surgery, and the last follow-up were measured and compared. Results: There were no significant differences between the two groups in terms of the general conditions（P>0.05）. The intervertebral height of mesh located segment immediately after operation between groups showed no significant difference(27.75±2.79mm vs 28.46±2.11mm，P>0.05), which was 25.66±2.80mm and 24.47±2.50mm of group A vs 26.76±2.13mm and 25.73±2.57mm of group B, respectively, at 2 months after operation and the final follow-up, with significant differences at the same time point(P<0.05). The titanium mesh subsidence values at 2 months and the last follow-up were 3.61±1.25mm and 1.09±0.67mm in group B, respectively, which were higher than those in group A of 2.33±0.61mm and 1.00±0.53mm(P<0.05). The fused segment Cobb angles decreased in both groups at 2 months postoperatively and the final follow-up compared with those immediately after operation(P>0.05). However, there was no significant difference in the fused segment Cobb angle between the two groups immediately after surgery, at 2 months after surgery, and at the last follow-up(P>0.05). The C2-7 Cobb angles were corrected in both groups immediately postoperatively, and all patients had significant decreases in C2-7 Cobb angles at 2 months postoperatively and the final follow-up(P<0.05), but there was no significant difference in the decreases in C2-7 Cobb angle between the two groups at the same time point(P>0.05). Loosening and displacement of the internal fixation were observed in four patients in group A at 2 months postoperatively but none in group B. Conclusions: The probability of mesh subsidence was higher when the mesh was placed caudally in patients with 3-level cervical spondylotic myelopathy undergone hybrid decompression and fusion.