Clinical effect of the nano-hydroxyapatite/polyamide66 cage in reconstruction of cervical stability: a midterm follow-up study

English Keywords:Cervical vertebrae  Spinal fusion  Nano-hydroxyapatite／polyamide 66  Polyetheretherketone

English Abstract:

  【Abstract】 Objectives: To explore the midterm outcomes of nano-hydroxyapatite/polyamide66 cage(n-HA/PA66 cage) in reconstructing the stability of anterior and middle cervical column by comparing with polyetheretherketone PEEK cage． Methods: A total of 174 patients who underwent the anterior cervical discectomy and fusion(ACDF) between January 2010 and January 2012 was reviewed. They were divided into two groups according to the implanted cage: 124 cases with n-HA/PA66 cage in group A, and 50 cases with PEEK cage in group B. Sex, age, intraoperative blood loss, operation time, complication rate, postoperative image and clinical effect were compared between two groups. The following radiographic measurements in all the patients were observed: cervical spine alignment, fused segments height, fused segments alignment. The rate of cage subsidence, cage displacement and bone fusion were evaluated by Brantigan score. The clinical outcomes were evaluated by visual analogue scale(VAS) score, Japan Orthopaedic Association(JOA) score and neck disability index(NDI). Results: There were no significant differences(P>0.05) of sex, age, preoperative VAS, preoperative JOA, preoperative NDI, operation time, cervical spine alignment, fused segments height, fused segments alignment, hospitalization time and intraoperative blood loss between two groups. In group B, 2 patients showed temporary sore throat, which disappeared in 72 hours after operation without dysphagia. No cerebrospinal fluid leakage, hematoma or wound infection was found in all patents. Patients had been followed up for an average of 52.10±24.30 months in group A, and 49.50±26.50 months in group B, without significant difference between the two groups(P>0.05). Cage subsidence occurred in 2 cases of group A and 3 cases of group B, there was significant difference of subsidence rate between the two groups(P<0.05). The cervical spine alignment, fused segments height, fused segments alignment singnificantly improved at postoperative and final follow-up. But, there was no significant difference of cervical spine alignment, fused segments height, fused segments alignment at postoperative or final follow-up between two groups(P>0.05). There was no cage displacement, cage breakage or other implant complication in the other patients. The Brantigan score was more than or 3 points in all the patients which showed satisfied fusion rate. The fusion time was 4.2±1.8 months in group A, and 4.1±2.0 months in group B, and there was no significant difference between the two groups(P>0．05). Conclusions: The n-HA/PA66 cage has satisfied similar rate of osseous fusion as PEEK cage and can effectively restore and maintain the height and alignment of fused segments. The n-HA/PA66 cage is an ideal bioactive material in the reconstruction of anterior and middle cervical column.