Surgical Outcomes Of Cervical Myelopathy Due To Ossification Of Posterior Longitudinal Ligament:Anterior Decompression And Fusion Versus Posterior Laminoplasty

BackgroundOssification of posterior longitudinal ligament(OPLL)is characterized by ectopic bone formation of the spinal ligament.It is most commonly found in Asian populations,especially in Japanese.The spinal cord can be compressed due to progression of this lesion,which can cause neurological deficits.The most common location is at the cervical region of the spine,and OPLL is considered to be a common cause of cervical myelopathy.Conservative treatment is ineffective in relieving neurological symptoms and preventing the progression of ossification.Therefore,surgery is usually the recommended treatment option.Both anterior decompression and fusion(ADF)and laminoplasty(LAMP)are the widely used procedures in treating cervical OPLL.ADF can achieve direct decompression of spinal cord by the removal of ossified lesion,and is in favor of restoring cervical spine alignment.However,ADF is technically demanding and associated with complications.LAMP can enlarge the available space around spinal cord and allow back shift of spinal cord,leading to indirect decompression of spinal cord.Although LAMP is low technically demanding,it increases the risk of local kyphotic deformity.Considerable controversy exists over the choice of surgical procedure for cervical myelopathy due to OPLL,ADF and LAMP.PurposeTo compare the surgical outcomes between ADF and LAMP for treatment of cervical myelopathy due to cervical OPLLMethods1.Inclusion Criteria and Exclusion Criteria(Retrospective study)1.1 Inclusion Criteria:(1)cervical myelopathy due to cervical OPLL,(2)received surgical treatment with ADF or LAMP,(3)no trauma,infection,tumor,or previous surgery,(4)more than 18 years and(5)had complete medical records.1.2 Exclusion Criteria:(1)did not complete minimum of 1 year of follow-up,(2)thoracic or lumbar OPLL,(3)yellow ligament ossified,(4)no contact information,(5)death(not related to surgery),(6)no patient's content,(7)surgery history of spine.2.Inclusion Criteria and Exclusion Criteria(Meta-analysis)2.1 Inclusion Criteria:(1)clinical studies comparing ADF with LAMP for cervical myelopathy due to OPLL,(2)study population 18 years and older,(3)minimum 12-months follow-up,(4)minimum 10 of sample size per group,(5)English literature.2.2 Exclusion Criteria:(1)animal studies,(2)biomechanical studies.,(3)duplicate publications of one trial,(4)case report,(5)letter,(6)revision,(7)technology note,(8)thoracic or lumbar OPLL,(9)commentaries,(10)reviews and meta-analysis3.Outcome IndexOutcome Index:(1)primary outcomes:? Japanese Orthpaedic Association(JOA)score,?neurological function recovery rate.(2)Secondary outcomes:?operation time,? blood loss,?complications rate,?reoperation rate,?cervical C2-C7 Cobb angle,? length of stay.4.Statistical MethodsFor retrospective study,all statistical analysis were performed by use of Statistical Packages for Social Sciences V22.0(SPSS,Chicago,IL,USA).Differences were tested using independent t-test for symmetrically distributed variables and non-parametric Wilcoxon test for other variables.For meta-analysis,all statistical analysis were conducted using Stata 14.0 software.Results1.Outcomes(Retrospective study)There was no significant difference in age,follow-up time,operation time,blood loss,length of stay,preoperative JOA score,preoperative occupying ratio of OPLL,preoperative anteroposterior diameter of spinal canal,preoperative and final follow-up C2-C7 angles,and the change of C2-C7 angle before and after operation between ADF and LAMP groups(P>0.05).The final follow-up JOA score and the neurological recovery rate were significantly higher in ADF group than in LAMP group.2.Meta-analysis OutcomesThe mean preoperative JOA score was similar between two groups.Compared with LAMP group,ADF group was higher at the mean postoperative JOA scores and mean recovery rate,reoperation rate,and longer at mean operation time(P<0.05).There was not significantly different in mean blood loss and complication rate between two groups.ConclusionADF and LAMP can improve neurological function for persons with cervical myelopathy due to OPLL.For cases of OPLL with segmental-type or canal occupying ratios?50%,ADF achieves better neurological improvement than LAMP.Cerebrospinal fluid leakage is a major complication after ADF,C5 paralysis and axial pain frequently results from LAMP.