Complications following cervicothoracic osteotomy for cervico-thoracic kyphosis caused by ankylosing spondylitis and treatment

English Keywords:Ankylosing spondylitis  Cervico-thoracic kyphosis  Pedicle subtraction osteotomy  Complication  Radiculopathy

English Abstract:

  【Abstract】 Objectives: The study aimed to investigate the incidence, clinical manifestations and prognosis of complications following cervico-thoracic osteotomy for cervico-thoracic kyphosis(CTK) secondary to ankylosing spondylitis(AS). Methods: A retrospective study of 11 AS patients with CTK who underwent surgery were performed. The average age was 33.4±14.0 years(range, 14-60 years). C7-T1 extensive osteotomy was performed in 3 cases with mild ossified anterior longitudinal ligament(OALL) while C7 pedicle subtraction osteotomy(PSO) was performed in 8 patients with severe OALL. Radiographs were analyzed for C2-T1 kyphosis(CK), C2-T1 sagittal vertical axis(C2 SVA), chin-brow vertical angle(CBVA), C2-7 Cobb angle in coronal plane and coronal balance distance(CBD) preoperatively, 1 week postoperatively and at final follow-up. Postoperative complications were also recorded including incidence, clinical manifestation and prognosis. Results: The mean follow-up period was 16.45 months(range, 6-48 months). The CK, C2 SVA and CBVA significantly improved at postoperative 1 week compared with those before operation(-11.45°±13.98° vs 17.64°±14.03°, 48.64±23.56mm vs 84.27±36.90mm, 10.18°±9.47° vs 42.45°±22.46°, all P<0.05), which showed no significant loss at final follow-up(P>0.05). Three patients presented with concomitant coronal deformity. The preoperative CBD and coronal Cobb angles were 48.5mm, 37mm, 78.7mm and 47.3°, 26.8°, 20.5° respectively, which were improved to 14.1mm, 6.1mm, 24.8mm and 14.4°, 9.3°, 6.3° one week after surgery. No obvious loss of correction was observed for all the parameters at final follow-up. The incidence of complications was 27.3% (3/11), including one case of osteotomized vertebral subluxation(VS) and two cases of C8 radiculopathy. The patient with VS presented with weakness and numbness of unilateral upper extremity. For the two patients with C8 radiculopathy, one presented with weakness of intrinsic muscles in the right hand, the other had numbness and weakness of left arm. The symptoms of the three patients were relieved six months postoperatively after rehabilitation and Halo-vest immobilization. Conclusions: C8 radiculopathy and VS were common complications following cervicothoracic osteotomy in AS patients with CTK. For patients with C8 radiculopathy, conservative treatment(rest and brace) till bony fusion could be considered first when there is extensive laminectomy intra-operatively, without abnormal intraoperative neuro-monitoring signals or VS on sagittal CT reconstruction, otherwise, surgical exploration should be performed when there is progressive muscle strength decrease and VS on CT image. For the VS, conservative bracing was indicated in the absence of significant neural compression or neurological deficits secondary to vertebral dislocation; Conversely, surgical intervention was warranted if dislocation resulted in neurological symptoms or was accompanied by extensive osseous defects.