Posterior occipito-cervical fusion in rheumatoid arthritis

Posterior occipitocervical (C0–3) fusion using polyaxial occipital condyle to cervical spine screw and rod fixation: a radiographic and cadaveric analysis

Numerous conditions affect the occipitocervical junction requiring treatment with occipitocervical fixation. In this paper the authors present their technique of craniocervical fixation achieved with the cephalad extension of posterior C1–3 polyaxial screw and rods to polyaxial screws placed in the occipital condyles. They retrospectively analyzed occipital condyle morphology obtained from CT analyses of 40 patients with normal cervical spines, evaluated occipital condyle screw placement feasibility in 4 cadavers, and provided a case report of a 70-year-old woman with rheumatoid arthritis, basilar invagination, and atlantoaxial instability who was treated with this novel technique. Based on radiographic analysis of occipital condyle anatomy, they concluded that on average a 3.5-mm-diameter × 20- to 30-mm-long screw can be safely placed at an angle of 20–33° from the sagittal plane. Overall, measuring the condylar heights (mean [± SD] 10.8 ± 1.5 mm, range 8.1–15.0 mm), widths (mean 11.1 ± 1.4 mm, range 8.5–14.2 mm), lengths (20.3 ± 2.1 mm, range 15.4–24.6 mm), and angles (mean 32.8 ± 5.2°, range 20.2–45.8°) by using CT studies is an accurate and precise method. This finding correlates with the results of prior anatomical studies of occipital condyles and is important in the planning of craniovertebral junction surgery.

Posterior Fusion in Patients with Trauma, Instability, and Tumor of the Cervical Spine

Trauma, instabilities and tumors of the cervical spine are treated with established methods of surgery. Therefore, anterior fusion is considered to be a standardized procedure for the lower cervical spine, while posterior and anterior instrumentation facilitates stabilization of the upper cervical spine. However, special situations that particularly require posterior instrumentation in traumatic lesions, tumor or other kinds of instabilities arise again and again. Neurological deficit symptoms, bone quality and related diseases fundamentally lead to a decision of posterior access and fusion. Different pathologies and corresponding reasons for posterior surgical interventions on the cervical spine are described in this paper and discussed using the current literature.

Rationale and design of The Delphi Trial – I(RCT)2: international randomized clinical trial of rheumatoid craniocervical treatment, an intervention-prognostic trial comparing 'early' surgery with conservative treatment [ISRCTN65076841]

Background

Rheumatoid arthritis is a chronic inflammatory disease, which affects 1% of the population. Hands and feet are most commonly involved followed by the cervical spine. The spinal column consists of vertebrae stabilized by an intricate network of ligaments. Especially in the upper cervical spine, rheumatoid arthritis can cause degeneration of these ligaments, causing laxity, instability and subluxation of the vertebral bodies. Subsequent compression of the spinal cord and medulla oblongata can cause severe neurological deficits and even sudden death. Once neurological deficits occur, progression is inevitable although the rapidity of progression is highly variable. The first signs and symptoms are pain at the back of the head caused by compression of the major occipital nerve, followed by loss of strength of arms and legs. The severity of the subluxation can be observed with radiological investigations (MRI, CT) with a high sensitivity.

The authors have sent a Delphi Questionnaire about the current treatment strategies of craniocervical involvement by rheumatoid arthritis to an international forum of expert rheumatologists and surgeons. The timing of surgery in patients with radiographic instability without evidence of neurological deficit is an area of considerable controversy. If signs and symptoms of myelopathy are present there is little chance of recovery to normal levels after surgery.

Design

In this international multicenter randomized clinical trial, early surgical atlantoaxial fixation in patients with rheumatoid arthritis and radiological abnormalities without neurological deficits will be compared with prolonged conservative treatment. The main research question is whether early surgery can prevent radiological and neurological progression. A cost-effectivity analysis will be performed. 250 patients are needed to answer the research question.

Discussion

Early surgery could prevent serious neurological deficits, but may have peri-operative morbidity and loss of rotation of the head and neck. The objective of this study is to identify the best timing of surgery for patients at risk for the development of neurological signs and symptoms.

OP-1 for cervical spine fusion: bridging bone in only 1 of 4 rheumatoid patients but prednisolone did not inhibit bone induction in rats

We used OP-1 (also called BMP-7) on a collagen type-1 carrier in atlanto-axial posterior fusions to promote bony healing after wire fixation. 4 patients who had instability between the atlas and axis due to rheumatoid disease received the implants. The patients were examined with conventional radiography postoperatively at 2, 6 and 10 months. In 3 patients, no new bone formation was detectable. In 1 patient, new bone bridged the fusion site at 6 months. 3 patients were on chronic steroid treatment, including the patient in whom bone formation was detected. To determine whether steroid treatment could be responsible for the low rate of bone induction, 24 rats each received OP-1 implants in an abdominal muscle pouch. They were divided into 3 groups receiving saline, 0.1 or 1.0 mg/kg BW of prednisolone daily until they were killed 3 weeks postoperatively. Specimens were decalcified for histology and the amount of calcium in the decalcifying solution was measured. All groups showed ossicles induced by OP-1, and no effect of prednisolone was detected. Thus the failures in the patients may have causes other than prednisolone treatment.

Atlantoaxial fusion and retrodental pannus in rheumatoid arthritis

STUDY DESIGN

This study analyzed the influence of atlantoaxial fusion in rheumatoid arthritis patients on inflammatory retrodental pannus.

OBJECTIVES

To determine the value of fusion on the magnitude of pannus as a compressive structure on the spinal cord.

SUMMARY OF BACKGROUND DATA

Transverse and vertical instability may lead to neurologic deficits from spinal cord compression. Increased size of the retrodental pannus can exacerbate the neurologic deterioration. Anterior removal of dens and pannus followed by posterior fusion has been proposed in such situations as a method to relieve spinal cord compression.

METHODS

Twenty-two patients with atlantoaxial instability and verified pannus on magnetic resonance imaging underwent posterior fusion of the upper cervical spine. These patients were followed 12 to 75 months after surgery by clinical, radiologic, and magnetic resonance imaging evaluations. The size of the pannus was compared before and after surgery.

RESULTS

In all patients, the retrodental pannus had significantly decreased or disappeared postoperatively.

CONCLUSIONS

Pannus reduction occurred even in patients whose disease was active or progressing, supporting the hypothesis that the pannus is more a reactive fibrous tissue resulting from instability rather than a direct consequence of the inflammatory process itself.

Posterior occipitoaxial fusion for atlantoaxial dislocation associated with occipitalized atlas

Between 1989 and 1994, 50 patients suffering from congenital atlantoaxial dislocation with either an assimilated atlas or a thin or deficient posterior arch of the atlas were treated with occipitocervical fusion using the technique described by Jain and colleagues in 1993 with a few modifications. An artificial bridge created from the occipital bone along the margin of the foramen magnum was fused to the axis using sublaminar wiring and interposed strut and lateral onlay bone grafts. Ten patients (20%) also underwent atlantoaxial lateral joint fusion by intraarticular instillation of bone chips. In 22 patients (44%) with irreducible dislocation, posterior fusion was preceded by transoral odontoidectomy. In seven patients (14%) with ventral compression, who showed marked clinical improvement on traction despite radiological evidence of persisting atlantoaxial dislocation, occipitocervical fusion was performed without ventral decompression. Seven patients (14%) underwent a single-stage transoral odontoidectomy and posterior fusion. There was no perioperative mortality and the osseous fusion rate was 88%. Of the 43 patients available at follow-up examination (range 3-12 months), 31 patients (72.09%) improved, seven (16.28%) remained the same, and five (11.6%) deteriorated in comparison with their preoperative status. Hence, this technique achieves a stable occipitocervical arthrodesis without supplemental external orthoses and facilitates early postoperative mobilization.

The management of acute spinal cord compression

Images