Unilateral exposure and contralateral-paravertebral-muscle-preserving laminoplasty in the treatment of multilevel degenerative cervical spondylosis

English Keywords:Cervical spondylosis  Posterior cervical approach  Unilateral exposure  Laminoplasty

English Abstract:

  【Abstract】 Objectives: To evaluate the clinical effect of unilateral exposure and contralateral-paravertebral-muscle-preserving laminoplasty in the treatment of multilevel cervical spondylosis. Method: Data of 76 patients diagnosed with multilevel degenerative cervical spondylosis who underwent open-door laminoplasty from March 2019 to December 2020 were reviewed retrospectively. There were 41 male patients and 35 female patients, with an average age of 61.4±8.2 years. The average postoperative follow-up was 16.3±5.2 months. Among them, 31 patients who underwent unilateral exposure and contralateral-paravertebral-muscle-preserving laminoplasty were defined as muscle-preserved group(MP), and 45 patients who underwent traditional open-door laminoplasty were enrolled and defined as traditional open-door laminoplasty group(LP). Patient characteristics such as age, sex and body mass index(BMI) were compared. Surgical parameters like the operative time, blood loss, amount of post-operative drainage were compared. The visual analog scale(VAS), neck disability index(NDI) and Japanese Orthopaedic Association(JOA) scores of the two groups were compared before operation, immediately after operation, 2 months after operation, 1 year after operation and at the last follow-up. The C2-C7 Cobb angle was measured on the lateral cervical spine X-ray film before and after operation and during clinical follow-up. The cross-sectional area of spinal canal was measured on CT cross section. Increased cross-sectional area of spinal canal was compared between the two groups. Results： All patients underwent operations successfully. In MP group and LP group, the average operative time was 75.4±19.3min and 88.3±21.2min, the mean blood loss was 97.8±36.2ml and 182.5±47.8ml, and the mean postoperative drainage was 134.2±40.3ml and 225.8±49.0ml, respectively. The operative time, blood loss, and postoperative drainage in MP group were significantly less than those in LP group(P<0.05). The postoperative scores of NDI and JOA in the two groups were significantly improved compared with those before operation(P<0.05), there was no significant difference in NDI and JOA scores between the two groups before operation and during follow-up(P>0.05). The neck pain VAS scores of MP group were lower than those of LP group immediately after operation and at 2 months after operation(P<0.05), but there was no significant difference between the two groups at 1 year follow-up(P>0.05). At 2 months after operation, the incidence of early postoperative axial neck pain in MP group and LP group were 19.7% and 28.5% respectively, and there was significant difference between the two groups(P<0.05). At 1 year after operation, the incidence of axial neck pain in two group were 13.2% and 14.6% respectively, and there was no significant difference between the two groups(P>0.05). The C2-C7 Cobb angles immediately after operation and at the last follow-up were 9.8°±8.4° and 8.1°±7.9° in MP group, which were 9.5°±8.4° and 4.0°±7.7° in LP group, respectively. There was no significant difference in the C2-C7 Cobb angle between the two groups before and immediately after operation(P>0.05). There were significant differences in the C2-C7 Cobb angle between the two groups during postoperative follow-ups(P<0.05). In MP group, the area of spinal canal increased by(109.6±18.4)% immediately after operation and (105.2±19.8)% at the final follow-up comparing with that before operation. In LP group, comparing with before operation, the area of spinal canal increased by (115.2±19.0)% immediately after operation and (111.4±20.9)% at the last follow-up. At each follow-up time point, the increase of average spinal canal area in LP group was slightly larger than that in MP group, but there was no significant difference between the two groups(P>0.05). Conclusions： Unilateral exposure and contralateral-paravertebral-muscle-preserving laminoplasty can reduce the operation time, bleeding, and postoperative drainage. It also can reduce the incidence of early postoperative axial neck pain.