Outcomes of instrumented fusion in the pediatric cervical spine
Authors: Hwang Steven W. , Gressot Loyola V. , Rangel-Castilla Leonardo , Whitehead William E. , Curry Daniel J. , Bollo Robert J. , Luerssen Thomas G. , Jea Andrew 
Published: September 2012

Object
The most common cause of cervical spine arthrodesis in the pediatric population is instability related to congenital or traumatic pathology. Instrumenting the cervical spine can be challenging given smaller anatomical structures, less ossified bone, and future growth potential and development. Studies in adult patients have suggested that using screw constructs results in improved outcomes with lower rates of instrumentation failure. However, the pediatric literature is limited to small retrospective series. Based on a review of the literature and their own patient series, the authors report that instrumenting the pediatric cervical spine with screw constructs may be safer and more effective than using wiring techniques.

Methods
The authors reviewed the existing pediatric cervical spine arthrodesis literature and contributed 31 of their own cases from September 1, 2007, to January 1, 2011. They reviewed 204 abstracts from January 1, 1966, to December 31, 2010, and 80 manuscripts with 883 total patients were included in the review. They recorded demographic, radiographic, and outcomes data—as well as surgical details—with a focus on fusion rates and complications.
Patients were then grouped into categories based upon the procedure performed: 1) patients who underwent fusions bridging the occipitocervical junction and 2) patients who underwent fusion of the cervical spine that did not include the occiput, thus including atlantoaxial and subaxial fusions. Patients were further subdivided according to the type of instrumentation used—some had posterior cervical fusion with wiring (with or without rod implantation); others had posterior cervical fusion with screws.

Results
The entire series comprised 914 patients with a mean age of 8.30 years. Congenital abnormalities were encountered most often (in 55% of cases), and patients had a mean follow-up of 32.5 months. From the entire cohort, 242 patients (26%) experienced postsurgical complications, and 50 patients (5%) had multiple complications. The overall fusion rate was 94.4%.
For occipitocervical fusions (N = 285), both screw and wiring groups had very high fusion rates (99% and 95%, respectively, p = 0.08). However, wiring was associated with a higher complication rate. From a sample of 252 patients, 14% of those treated with screw instrumentation had complications, compared with 50% of patients treated with wiring (p < 0.05).
In cervical fusions not involving the occipitocervical junction (N = 181), screw constructs had a 99% fusion rate, whereas wire instrumentation only had an 83% fusion rate (p < 0.05). Similarly, patients who underwent screw fixation had a lower complication profile (15%) when compared with those treated with wiring constructs (54%, p < 0.05).

Conclusions
The results of this study are limited by variations in construct design, use of orthoses, follow-up duration, and newer adjuvant products promoting fusions. However, a literature review and the authors' own series of pediatric cases suggest that instrumentation of the cervical spine in children may be safer and more efficacious using screw constructs rather than wiring techniques.