Efficacy Analysis Of Improved Surgical Treatment For Chiari Typeâ… Malformation

ObjectivesChiari malformation (Chiari Malformation，CM or Arnold-Chiari Malformation ACM)isa congenital diseases. Clinically, Chiari type Ⅰmalformation is the most commonmalformation. It is defined by the caudal extension of the cerebellar tonsils through theforamen magnum into the cervical canal. The cerebellar tonsils reduce the posterior fossavolume and cause cerebrospinal fluid (CSF) flow disturbance at the craniovertebraljunction. It often present with a complex clinical picture. Chiari type Ⅰmalformation isfrequently associated with syringomyelia (often present in cervical spinal cord and upthoracic spinal) and hydrocephalus. Surgical treatment of the patient with symptomaticChiari Ⅰmalformation is the main method. But there is no optimal surgery. Posteriorfossa decompression (PFD), posterior fossa decompression and duralasty (PFDD)、tonsillar reduction (TR) are the common procedure to enlarge the posterior fossa volume,restore CSF flow, and resolve syrinx formation. Outcome assessment for the managementof Chiari type1malformation is difficult as the lack of a reliable and specific surgicaloutcome assessment scale. The Chicago Chiari Outcome Scale (CCOS) was a newlydeveloped outcome scoring system with a simple and quantifiable assessing procedure in 2012.40adult Chiari type Ⅰmalformation patients underwent improved tonsillectomywithout craniectomy. Assess the efficacy of improved surgical treatment accordingChicago Chiari Outcome Scale (CCOS), traditional evaluation, imaging, comparing withimprovement rate in literature.Methods40cases with Chiari malformation underwent improved treatment in our hospital fromOctober2011to October2013. Neck care is essential after operation.Intraoperative ultrasonography could be utilized to monitor the CSF flow, cisternamagna volume, which directly compared the decompression effect before and aftertonsillar resection. Tonsillectomy was achieved by subpial resection to reduce theelongated cerebellar tonsils. The pial mater was kept as intact as possible during thesection of tonsils. After removal of tonsil tissues, the pial mater was gently suturedtogether, with the intention of forming a capsule to wrap and hold the cerebellar tissue andpreventing adhesion. We used the synthetic dura mater or periosteum to patch up and closethe incision of dura, then the occipital bone was put back and firmly fixed. All the patientswere followed up6-18months postoperation. The CCOS and traditional assessment wasintroduced into our study to assess recovery and outcome of the patients after the surgery.MRI was used to see the posterior fossa and syrinx formation.Chi-square test was used to compare the improvement rate (SPSS17.0). A P value of <0.05was considered statistically significantResults:40patients (18males and22females) underwent initial surgical treatment for CM-1inour department. The mean age at time of surgery was40.6years old. Within the40analyzed patients,36cases (90%) scored11or higher, labeled as good outcome;4cases(10%) scored between4and10, labeled as poor outcome. Efficacy between the twogroups were roughly equal, the difference was not statistically significant (χ2=1.491，P=0.222>0.05). Through traditional evaluation methods, clinical improvement (the group of improved) was evident in34(85%) patients; no improvement or similar topreoperative status (the group of unchanged) was observed in5patients (12.5%);1patients (2.5%) showed worse condition or recurring complications after surgery. Efficacybetween the two groups were roughly equal, the difference was not statistically significant(χ2=1.117，P=0.291>0.05)Base on the extent of herniation, we divided three groups: C0-C1,C1-C2,below C2There are27patients in C0-C1group,24cases scored11or higher, labeled as goodoutcome;3cases scored between4and10, labeled as poor outcome.23cases gotimproved,4cases got unchanged. There are11patients in C1-C2group,10casesscored11or higher, labeled as good outcome;1cases scored between4and10, labeledas poor outcome.9cases got improved,1case got unchanged,1case got worse.The difference between different groups was not statistically significant (P>0.05)Postoperative MRI showed that23of27patients (85.2%) achieved a favorable outcome;that is, syrinxes were totally collapsed or remarkably reduced. Syrinx size stabilized inthree patients. And one is deterioration.ConclusionImproved surgical treatment includes removing cerebellar tonsil subpial, suturing thepial mater and dura, put back and firmly fixing the occipital bone. It is a safe and effectivesurgical treatment of CM Ⅰ. According to this study, clinical outcome(CCOSimprovement rate90%, traditional evaluation improvement rate (85%) is better than thecommon group, although, there is no statistically significant differences between theimproved group and traditional PFD and/or PFDD group. Our research has small sampleand short follow-up, so we need more patients and longer follow-up to further study.