Screw fixation of the upper cervical spine in the pediatric population

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Rigid fixation of the upper cervical spine has become an established method of durable stabilization for a variety of craniocervical pathological entities in children. In children, specifically, the use of C1–2 transarticular screws has been proposed in recent literature to be the gold standard configuration for pathology involving these levels. The authors reviewed the use of rigid fixation techniques alternative to C1–2 transarticular screws in children. Factors evaluated included ease of placement, complications, and postoperative stability.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Seventeen patients, ranging in age from 3 to 17 years (mean 9.6 years), underwent screw fixation involving the atlas or axis for a multitude of pathologies, including os odontoideum, Down syndrome, congenital instability, iatrogenic instability, or posttraumatic instability. All patients had preoperative instability of the occipitocervical or atlantoaxial spine demonstrated on dynamic lateral cervical spine radiographs. All patients also underwent preoperative CT scanning and MR imaging to evaluate the anatomical feasibility of the selected hardware placement. Thirteen patients underwent C1–2 fusion, and 4 underwent occipitocervical fusion, all incorporating C-1 lateral mass screws, C-2 pars screws, and/or C-2 laminar screws within their constructs. Patients who underwent occipitocervical fusion had no instrumentation placed at C-1. One patient's construct included sublaminar wiring at C-2. All patients received autograft onlay either from from rib (in 15 patients), split-thickness skull (1 patient), or local bone harvested within the operative field (1 patient). Nine patients' constructs were supplemented with recombinant human bone morphogenetic protein at the discretion of the attending physician. Eight patients had surgical sacrifice of 1 or both C-2 nerve roots to better facilitate visualization of the C-1 lateral mass. One patient was placed in halo-vest orthosis postoperatively, while the rest were maintained in rigid collars.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>All 17 patients underwent immediate postoperative CT scanning to evaluate hardware placement. Follow-up was achieved in 16 cases, ranging from 2 to 39 months (mean 14 months), and repeated dynamic lateral cervical spine radiography was performed in these patients at the end of their follow-up period. Some, but not all patients, also underwent delayed postoperative CT scans, which were done at the discretion of the treating attending physician. No neurovascular injuries were encountered, no hardware revisions were required, and no infections were seen. No postoperative pain was seen in patients who underwent C-2 nerve root sacrifice. Stability was achieved in all patients postoperatively. In all patients who underwent delayed postoperative CT scanning, the presence of bridging bone was shown spanning the fused levels.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Screw fixation of the atlas using lateral mass screws, in conjunction with C-2 root sacrifice in selected cases, and of the axis using pars or laminar screws is a safe method for achieving rigid fixation of the upper cervical spine in the pediatric population.</jats:p></jats:sec>

Complications and outcomes of posterior fusion in children with atlantoaxial instability

“…One patient sustained injury to the vertebral artery. Similarly, Haque et al [11] reported on four O-C fusion cases with a C1 lateral mass screw, C2 pars screw, and laminar screw. These patients did not have any significant morbidity associated with the procedure and all achieved solid fusion.…”

“…C1-2 transarticular screw fixation (Magerl technique [3]) and its effectiveness in pediatric patients have been described [8,16,17]. Similarly, some studies reported that the C1 lateral screw and C2 pedicle screw technique (Goel-Harms constructs [4,5]) provide stabilization and promotes fusion in pediatric patients with AAI [9][10][11][12][13]. Also, unlike wiring techniques, C1-2 transarticular screw and Goel-Harms constructs do not require that the patient be placed in a halo vest postoperatively [13].…”

“…Recently, some small case series on O-C fusions with rod and screw fixation in pediatric patients were reported [11,15,16]. Jea et al [14] recently reported on a series of pediatric patients in whom they incorporated lateral mass screws and pedicle screws within occipito-cervical or atlantoaxial constructs.…”

“…Magerl et al [3] first proposed the use of C1-C2 transarticular screws in adults, and an alternative technique, namely C1 lateral mass screws and C2 pedicle screws [4,5] or C2 translaminar screws [6] has been reported. More recently, these techniques are being used in pediatric patients [7][8][9][10][11][12][13][14][15][16][17]; however, there are no detailed reports on the risks with these techniques when used in children. Furthermore, the medical community does not fully understand the long-term effects of posterior cervical spine fusion in the skeletally immature spine, and there are only a few published articles on these effects [18,19].…”

Modern Instrumentation of the Pediatric Occiput and Upper Cervical Spine

“…2). The routine depth of screws in the lateral mass has been shown to be possible up to 20 mm in children [10]. We use lateral fluoroscopy to determine the length of drilling and have found that stopping short of the posterior aspect of the anterior ring outline is adequate, taking care to be lined up in the middle with regard to the cranial-caudal direction.…”