Posterior fixation of subaxial cervical spine fractures in patients with ankylosing spondylitis

Abstract

Cervical spine fractures in patients with ankylosing spondylitis are serious and potentially lethal injuries with high complication rates. Treatment obstacles include long lever arms that generate large forces on any fixation device, osteoporosis, and, usually, kyphotic deformity. The Olerud Cervical Fixation System (OC), with cervical pedicle screws and rods, offers an opportunity to create a biomechanically stable posterior fixation in these complicated cases. The present study is a retrospective chart review and a radiological follow-up of patients with this diagnosis, treated at our department between 1995 and 2000. Nineteen patients (two women) with a mean age of 60 years (32-78 years) were included. The fracture levels were predominantly C5-C6 (five patients) and C6-C7 (five patients). All patients were treated with a long posterior fixation with the OC, and in four patients this was combined with an anterior plate fixation. One patient with severe lordosis also received a short posterior plate fixation. The patients' notes and plain radiographs have been reviewed. Five patients died during the post-operative follow-up period; the others had a mean follow-up time of 24 months (10-55 months). Eleven patients had no neurological deficits preoperatively. One of them developed moderate weakness in his right arm, postoperatively, due to a misplaced pedicle screw in the right pedicle of C5. However, after extraction of the screw he almost totally recovered in 6 months. Eight patients had neurological deficits. Two were paraplegic; two had motor weakness combined with sensory deficiency, and four had a sensory deficiency. Two of the patients with neurological deficits improved postoperatively, but the others were unchanged. Peroperative problems were recorded in five patients; one C6 pedicle was perforated, and two patients had pedicles on one or more levels that the surgeon was not able to probe. In one of the latter patients, transfacet screws were chosen, instead, for one of the levels. Extensive peroperative bleeding was encountered in two patients. One deep-wound infection was noted, postoperatively, and required surgical drainage, but no patients have been re-operated due to loosening of the instrument or to healing problems. In conclusion, the results of the present study indicate that the OC--and possibly other similar long-fixation systems that allow using both pedicle screws and lateral mass screws rigidly connected to a rod--is suited for treating subaxial cervical spine fractures in patients with ankylosing spondylitis, allowing high healing rates.

Fig. 1

Radiographs of a 32-year-old man (No. 10 in Table 1) with ankylosing spondylitis. After a C6-fracture in a bicycle accident, he was stabilized with OC from C2 to T1, using transarticular screws in C2, pedicle screws in T1, and lateral mass screws at levels C5 and C7. a preoperative lateral; b postoperative lateral; c postoperative antero-posterior; and d lateral at follow-up at 55 months

Fig. 2

Radiographs of a 51-year-old man (No. 9 in Table 1) with ankylosing spondylitis. He fell indoors on his pelvic area, with an indirect axial compression of the spine. X-rays showed a C7-fracture. However, when the cervical spine was exposed surgically through a posterior approach, the fracture system was visible all the way up to the C4 level, posteriorly. Due to severe hyperlordosis in his cervical spine, and related problems in fixating long rods to the mid-cervical spine, he was stabilized with OC from occiput to T2, but also with an anterior plate at C6–C7 and posterior limited-contact-dynamic-compression plates (LCDCP) at C3–T1. a preoperative lateral; b preoperative CT (sagittal reformation); and c lateral at follow-up at 14 months

Fig. 3

Radiographs of a 54-year-old woman (No. 1 in Table 1) with ankylosing spondylitis. A fall against a bookcase at home fractured level C6–C7. She was stabilised with OC from C4 to T3 using cervical pedicle screws and rods. a preoperative lateral; b postoperative lateral