Posterior C1-C2 Fixation Research Articles

C1 dome-like laminotomy and posterior C1–C2 polyaxial screw-rod fixation for a patient with cervical myelopathy due to a retro-odontoid pseudotumor

A 49-year-old man presented with progressive cervical myelopathy caused by a retro-odontoid mass, with associated developmental canal stenosis at C1, and C1–C2 instability. Surgery was scheduled for a dome-like laminotomy at C1, posterior C1–C2 fixation using C1 lateral mass screws and C2 pedicle screws, and structural bone grafting between C1 and C2. Prior to surgery, we produced a 3-dimensional full-scale model of the patient’s cervical spine and performed a simulation of the scheduled surgery. Through the simulation, we accurately evaluated the laminotomy sites and the screw insertion points. During the actual surgery, all procedures were successful. After surgery, the patient’s neurological deficits markedly improved. Successful C1–C2 fusion, adequate decompression of the spinal cord, and spontaneous regression of the retro-odontoid mass were achieved by this procedure without any apparent restriction in neck movement.

C2 Pedicle Screw and Plate Combined With C1 Titanium Cable Fixation for the Treatment of Alantoaxial Instability not Suitable for Placement of C1 Screw

A method of atlantoaxial stabilization using individual fixation of the C1 posterior arch and the C2 pedicle with C2 pedicle screws and plates combined with C1 titanium cables is described. In addition, the clinical results of this method on 8 patients are described. To describe the method and the clinical and radiographic results for posterior C1-C2 fixation with a combined implant system. Stabilization of the atlantoaxial complex is a challenging procedure because of the unique anatomy of this region. Fixation by plate or rod and C1 and C2 screw and structural bone grafting leads to excellent fusion rates. The technique is technically demanding and has a potential risk of the injuries to the vertebral artery, the internal carotid artery, spinal cord, and hypoglossal nerves. In addition, how to stabilize the atlantoaxial complex in the cases not suitable for placement of C1 screw is not described in the literature. To address these limitations, a method of C1-C2 fixation has been developed: bilateral insertion of C2 pedicle screws and rolling of C1 titanium cable through the posterior arch of atlas and the cranial hole of the plate, followed by C1-C2 plate fixation. From February 2003 to March 2006, 8 patients with atlantoaxial instability and not suitable for placement of C1 screw were included in this study: 5 cases of broken C1 pedicle screw trajectory and 3 cases of C1 anatomic anomalies. Skull traction was performed in each patient preoperatively. The pedicle screws were inserted into C2 pedicles in the direction as its axis. C1 titanium cable was rolled superior to lower through posterior arch of atlas in the cases not suitable for placement of C1 screw. The C1-C2 plate was slightly bent to fit the upper cervical contour. Hyperflexion alignment of the atlantoaxial complex was corrected by application of extension force created by tightening of the nut on the pedicle screws and the C1 titanium cable, which was passed through the cranial hole of the plate. Morselized autogenous cancellous iliac grafts were placed on the surface of the posterior arches of both atlas and axis. All patients were assessed clinically for neurologic recovery by Odom's method. There were 5 males and 3 females with a mean age of 37.8 years (range, 17 to 59 y). There were 2 cases of old odontoid fracture, 2 cases fresh odontoid fracture (Aderson II C), 2 cases atlas transverse ligament laxation, 2 cases atlas transverse ligament rupture, and in these cases, 5 cases had failed placement of C1 screw because of broken C1 pedicle screw trajectory and 3 cases not suitable for placement of C1 screw because of anatomic anomalies. There were no spinal cord and vertebral artery and nerve injury after surgery. Follow-up duration was from 18 to 55 months with the average of 29 months. The plant bones all fused and there were no internal fixation rupture and mobility. All the patients showed improvement. C2 pedicle screw and plate combined with C1 titanium cable could be used to treat atlantoaxial instability in the cases not suitable for placement of C1 screw.

POSTERIOR REDUCTION AND FIXATION OF AN UNSTABLE JEFFERSON FRACTURE WITH C1 LATERAL MASS SCREWS, C2 ISTHMUS SCREWS, AND CROSSLINK FIXATION

Abstract Objective: We sought to describe a modified technique for the reduction and stabilization of unstable Jefferson fractures. Clinical Presentation: We present the case of an isolated unstable Jefferson fracture in a 33-year-old woman. The patient was the victim of a motor vehicle accident. Her neurological examination was normal. A cervical computed tomographic scan revealed an isolated Jefferson fracture that we thought to be unstable when we applied the Spence criteria. Technique: The fracture was treated by a technical variant of C1–C2 posterior fixation with compression on the rods by means of a crosslink connector, allowing the reduction of the atlantoaxial lateral mass overhanging. C1–C2 fusion with posterior iliac crest bone graft was added. Conclusion: The 1-year radiological follow-up evaluation showed a complete consolidation of the fracture lines and atlantoaxial stability. This technique could be an option for the reduction and stabilization of the unstable Jefferson fractures.

Posterior reduction and fixation of an unstable Jefferson fracture with C1 lateral mass screws, C2 isthmus screws, and crosslink fixation: technical case report.

We sought to describe a modified technique for the reduction and stabilization of unstable Jefferson fractures. We present the case of an isolated unstable Jefferson fracture in a 33-year-old woman. The patient was the victim of a motor vehicle accident. Her neurological examination was normal. A cervical computed tomographic scan revealed an isolated Jefferson fracture that we thought to be unstable when we applied the Spence criteria. The fracture was treated by a technical variant of C1-C2 posterior fixation with compression on the rods by means of a crosslink connector, allowing the reduction of the atlantoaxial lateral mass overhanging. C1-C2 fusion with posterior iliac crest bone graft was added. The 1-year radiological follow-up evaluation showed a complete consolidation of the fracture lines and atlantoaxial stability. This technique could be an option for the reduction and stabilization of the unstable Jefferson fractures.

Current Concepts in Posterior C1-C2 Fixation

Historically, fixation into C1 has been limited by the inability to attach a stable, longitudinal construct to the adjacent motion segments. Over the past several years, the introduction of universal polyaxial screw/rod instrumentation for the posterior cervical spine has enabled the surgeon to individually anchor into C1 and C2, providing stability comparable to transarticular screws, versatility of incorporating the occiput and the subaxial cervical spine easily into the construct, with safer and less difficult screw insertion. There has been considerable confusion in the literature regarding screws placed into the C2 vertebra from a posterior approach, with the distinction between C2 pedicle screws and C2 pars interarticularis screws hinging on the anatomic definitions of the true pedicle and pars interarticularis. Additionally, the recent advent of the C2 intralaminar screw has been introduced as a safe, alternative option for purchase into the C2 vertebra. We present a detailed discussion of the current trends in posterior atlantoaxial fixation.

Posterior C1-C2 fusion with polyaxial screw and rod fixation.

A novel technique of atlantoaxial stabilization using individual fixation of the C1 lateral mass and the C2 pedicle with minipolyaxial screws and rods is described. In addition, the initial results of this technique on 37 patients are described. To describe the technique and the initial clinical and radiographic results for posterior C1-C2 fixation with a new implant system. Stabilization of the atlantoaxial complex is a challenging procedure because of the unique anatomy of this region. Fixation by transarticular screws combined with posterior wiring and structural bone grafting leads to excellent fusion rates. The technique is technically demanding and has a potential risk of injury to the vertebral artery. In addition, this procedure cannot be used in the presence of fixed subluxation of C1 on C2 and in the case of an aberrant path of the vertebral artery. To address these limitations, a new technique of C1-C2 fixation has been developed: bilateral insertion of polyaxial-head screws in the lateral mass of C1 and through the pars interarticularis into the pedicle of C2, followed by a fluoroscopically controlled reduction maneuver and rod fixation. After posterior exposure of the C1-C2 complex, the 3.5-mm polyaxial screws are inserted in the lateral masses of C1. Two polyaxial screws are then inserted into the pars interarticularis of C2. Drilling is guided by anatomic landmarks and fluoroscopy. If necessary, reduction of C1 onto C2 can be accomplished by manipulation of the implants, followed by fixation to the 3-mm rod. For definitive fusion, cancellous bone can be added. No structural bone graft or wiring is required. In selected cases, e.g., C1-C2 subluxation or fractures in young patients in whom only temporary fixation is necessary, the instrumentation can be removed after an appropriate time. Because the joint surfaces stay intact, the patient can regain motion in the C1-C2 joints. Thirty-seven patients underwent this procedure. No neural or vascular damage related to this technique has been observed. The early clinical and radiologic follow-up data indicate solid fusion in all patients. Fixation of the atlantoaxial complex using polyaxial-head screws and rods seems to be a reliable technique and should be considered an efficient alternative to the previously reported techniques.