Comparison of clinical and radiological outcomes between modified Gallie graft fusion-wiring technique and posterior cervical screw constructs for Type II odontoid fractures

Abstract

The aim of this study was to compare clinical and radiological outcomes between modified Gallie graft fusion-wiring technique and posterior cervical screw constructs for Type II odontoid fractures, and hope to provide references in decision making and surgical planning for both spinal surgeons and surgically treated patients.This is a retrospective study. By retrieving the medical records from January 2005 to July 2015 in our hospital, 53 Type II odontoid fracture patients were reviewed. According to the instrumentation type, patients were divided into 2 groups: Wiring group and Screw group. Three categorized factors were analyzed statistically: patient characteristics: age, body mass index, preoperative neurological status, duration, complicated injuries; surgical variables: surgery time, blood loss, vertebral artery injury, spinal cord or nerve root injury, major systemic complications, wound infection, pain at the bone donor area, instrumentation failure, revision rate; and radiographic parameters: preoperative and final follow-up data of C0-2 curvature, C2-7 curvature, C2-C7 sagittal vertical axis, C7 slope, fracture classification, separation, and displacement of odontoid fracture, fusion rate. An additional comparison of surgical outcomes was done, including patient satisfaction, visual analog scale score for neck pain, neck stiffness, medical expense.There was no statistically significant difference between the 2 groups in patient characteristics of age, sex, body mass index, preoperative neurological status, duration, and complicated injuries. No statistically significant difference was noted in surgical variables of blood loss, vertebral artery injury, spinal cord or nerve root injury, major systemic complications, wound infection, bone harvested zone pain, instrumentation failure, revision rate. The surgery time was shorter in Wiring group than that in Screw group, with a statistically significant difference. We noted no significant difference between the 2 groups when comparing radiographic parameters of preoperative and final follow-up data of C0-2 curvature, C2-C7 sagittal vertical axis, fracture classification, the separation and displacement of odontoid fracture, and fusion rate. Although we noted no significant difference in preoperative C2-7 curvature and C7 slope, the final follow-up data showed that C2-7 curvature and C7 slope were smaller in Wiring group than that in Screw group. We noted no significant difference in visual analog scale score, neck stiffness, and neurological status at final follow-up. The medical expense was less in Wiring group; the patient satisfaction was lower in the Wiring group than that in the Screw group.The modified Gallie graft fusion-wiring technique provided solid fusion and stabilization for patients with Type II odontoid fractures, Gallie graft fusion-wiring resulted in less surgery time, less medical expense, but lower patient satisfaction when compared with the posterior cervical screw constructs.

Figure 1

Male, 35 years old, duration from injury to operation was 5 days. (A) Preoperative CT showed type II C odontoid fracture, with fracture anterior displacement = 7.3 mm. (B, C) Reduction of the displaced odontoid fracture was attempted using the Mayfield head-holding device. (D–F) Postoperative lateral, flexion, and extension X-ray showed the cervical alignment and mobility was excellent after modified Gallie graft fusion-wiring instrumentation. (G–K) Twelve-month follow-up CT scan showed evident bridging bone across the odontoid fracture site in coronal and sagittal CT-scans in neutral head position.

Figure 2

Male, 29 years old, duration from injury to operation was 8 days. (A–C) Preoperative lateral, flexion, and extension X-ray showed odontoid fracture. (D) Preoperative MRI showed odontoid fracture without spinal cord compression. (E, F) Preoperative CT showed type II B odontoid fracture, with fracture anterior displacement = 8.1 mm. (G) Reduction of the displaced odontoid fracture was attempted using the Mayfield head-holding device. (H–J) Postoperative lateral, flexion, and extension X-ray showed posterior C1 lateral screw-C2 pedicle screws fixation. (K) Three-month follow-up CT scan showed bridging bone across the odontoid fracture site in sagittal CT-scans in neutral head position. (I) Twelve-month follow-up CT scan showed evident bridging bone across the odontoid fracture site in sagittal CT-scans in neutral head position.

Figure 3

C0–2 Cobb angle was measured as the angle between the McGregor line and lower endplate of the C2 vertebra. A positive value indicates lordosis between the occiput and C2, and a negative value indicates kyphosis between the occiput and C2. C2-C7 sagittal vertical axis (SVA) was the horizontal distance between the C2 plumb line and the posterior corner of C7.

Figure 4

C2–7 Cobb angle (Jackson method) was measured at the intersection of the posterior body tangent lines on C2 and C7. C7 slope was defined as an angle formed between the C7 upper end plate and the horizontal plane.

Figure 5

Separation and displacement of odontoid fracture.

Figure 6

Fracture healing was defined as evident bridging bone across the odontoid fracture site on 1 of the cortices in sagittal CT-scans in neutral head position.

Figure 7

(A) Preoperative lateral X-ray showed C2 fracture, with Geier-deformity. (B) Postoperative lateral X-ray showed C1 lateral mass screws with C2 pedicle screws. (C) C1 lateral mass screw loosening 11 months postoperatively. (D) CT showed C1 lateral mass screw loosening bilaterally. (E) Revision surgery with new C1 lateral mass screw reimplantation.