Effect on the morphological change in the posterior cervical muscle of laminoplasty with preservation of unilateral musculo-ligamentous complex in the treatment of patients with ossification of the posterior longitudinal ligament

English Keywords:Ossification of posterior the longitudinal ligament in cervical spine  Laminoplasty with preservation of unilateral muscular-ligamentous complex  Posterior cervical muscles  Functional cross-sectional area  Fatty infiltration

English Abstract:

  【Abstract】 Objectives: To explore the influence of posterior cervical laminoplasty with preservation of unilateral musculo-ligamentous complex on posterior cervical muscles in patients with cervical ossification of the posterior longitudinal ligament(OPLL). Methods: Retrospectively reviewed patients diagnosed with cervical OPLL and received C3-7 laminoplasty with preservation of unilateral musculo-ligamentous complex in our institute. We collected clinical data such as age, gender, body mass index (BMI), C2-7 Cobb angle, cervical range of motion, cervical visual analog scale(VAS), mJOA score and neck disability index (NDI) with a minimal 24 months follow-up. The cross-sectional area(CSA), functional CSA(FCSA) and fatty infiltration(FI) of cervical posterior muscles in each segment were measured at pre-operation and 24 months after surgery. T-test, Chi-square test were used for univariable test. Results: 16 cases were included in this research, 9 were male and 7 were female. The average age was 52.94±7.07 years old. Of all the patients, 6 cases were diagnosed with OPLL of local type, 5 were of segmental type, and 5 were of continuous type. 2 years after surgery, there wasn′t any significant change in C2-7 Cobb angle and disc height. There was significant change of range of motion(ROM) pre- and post-operatively(40.33°±12.03° vs 27.09°±11.09°). Comparison was made between the posterior cervical muscles pre- and post-operatively, at C3/4 level, the FCSA was decreased and FI increased significantly in paraspinal muscle, FI increased significantly in splenius capitis(SC). At C4/5 and C5/6 level, FCSA and FI changed significantly in paraspinal muscle and SC. At C6/7 level, FCSA and FI in paraspinal muscle, CSA, FCSA and FI in SC all changed significantly. The paraspinal muscle on the left side and right side were compared post-operatively. At C3/4 level, CSA and FI in paraspinal muscle are significantly larger on the right side. At C4/5 level, FI of SC was significantly larger on the left side. At C5/6 level, CSA and FCSA of paraspinal muscle was significantly larger on the right side. At C6/7 level, FI of paraspinal muscle was significantly larger on the left side. Conclusions: In patients with cervical OPLL, posterior laminoplasty will significantly decrease the CSA and FCSA of paraspinal muscle and increase the FI. Laminoplasty with preservation of unilateral muscular-ligamentous complex will effectively prevent the decrease of muscle volume and increase of fatty infiltration in the preserved side.