Preliminary observation of the clinical efficacy of posterior atlantoaxial lateral mass joint cage graft fusion and internal fixation in the treatment of irreducible atlantoaxial dislocation

English Keywords:Atlantoaxial dislocation  Posterior approach  Lateral mass joint  Graft fusion  Cage

English Abstract:

  【Abstract】 Objectives: To investigate the clinical efficacy of posterior atlantoaxial lateral mass joint cage graft fusion and internal fixation for the treatment of irreducible atlantoaxial dislocation(IAAD) through comparing with the transoral pharyngeal release and posterior reduction, fixation and fusion procedure. Methods: The clinical data of patients with IAAD treated with posterior atlantoaxial lateral mass joint cage graft fusion and internal fixation(23 cases, cage group) and transoral pharyngeal release and posterior reduction, fixation and fusion(25 cases, control group) in our department from January 2018 to August 2022 were retrospectively analyzed. There were 8 males and 15 females in the cage group, aged 9-79(48.35±14.38) years old, while 6 males and 19 females were in the control group, who aged 21-69(47.84±13.51) years old. The operative time, intraoperative bleeding, length of hospital stay and complications were recorded. Japanese Orthopaedic Association(JOA) score was used to evaluate nerve functions, and atlantodental interval(ADI), vertical distance from odontoid process to Chamberlain′s line(DOCL), cervicomedullary angle(CMA), and clivus-axial angle(CAA) were measured to evaluate the reduction of atlantoaxial dislocation preoperatively, postoperatively and at final follow-up. The conditions of lateral mass joint cage and posterior bone graft fusion were also assessed. Results: All the patients had good positions of internal fixation, adequate decompressions and satisfactory reductions, and all symptoms were significantly relieved without vertebral artery injury and aggravation of spinal cord injury. The operative time, intraoperative bleeding and length of hospital stay in the cage group were 133.04±34.04min, 119.13±54.77mL and 14.74±6.10d, which were significantly less or shorter than those in the control group(253.20±53.98min, 181.20±45.40mL, 23.96±5.47d), respectively. The preoperative JOA, ADI, DOCL, CMA, CAA of the cage group were 6.33±1.13 points, 7.31±3.05mm, 9.47±3.32mm, 122.89°±12.58°, 122.02°±12.50° respectively, which were 13.04±2.17 points, 2.18±0.67mm, 0.89±1.00mm, 148.81°±5.43°, 146.70°±9.32° postoperatively, and 14.89±1.17 points, 2.09±0.69mm, 0.83±0.86mm, 149.10°±5.11°, 146.89°±8.95° at final follow-up. The preoperative JOA, ADI, DOCL, CMA, CAA of the control group were 6.76±1.21 points, 7.70±0.97mm, 10.56±1.99mm, 121.53°±4.87°, 123.77°±8.95° respectively, which were 13.26±1.32 points, 1.89±0.50mm, 1.13±1.08mm, 151.40°±6.15°, 149.86°±5.58° postoperatively, and 15.02±0.88 points, 1.87±0.44mm, 0.87±1.39mm, 149.48°±4.06°, 149.94°±6.61° at final follow-up. The JOA, ADI, DOCL, CMA and CAA of postoperative and final follow-up were significantly improved in both groups compared with those before operation(P<0.05), and the postoperative JOA score was statistically different from that at final follow-up in both groups(P<0.05), but there was no significantly statistical difference in ADI, DOCL, CMA and CAA between postoperative and final follow-up in both groups(P>0.05). 1 case of incision infections occurred in the cage group; 3 cases of incision infections(2 oropharyngeal, 1 posterior) and 1 case of cerebrospinal leakage occurred in the control group. The internal fixations were all stable in positions during follow-up, and osseous fusion was achieved at final follow-up in both groups, besides, there was no loss of joint space height in the cage group. Conclusions: Posterior atlantoaxial lateral mass joint cage graft fusion and internal fixation has similar efficacy for treating IAAD compared with transoral pharyngeal release and posterior reduction, fixation and fusion, but with the addition of implant fusion sites, which can be more effectively fused, and apart from avoiding transoral surgery, it can reduce the operative time, intraoperative bleeding, hospitalization time and complications.