Results of a longer than 10-year follow-Up of patients with rheumatoid arthritis treated by occipitocervical fusion

The Influence of Reducing Disease Activity Score on Cervical Spine Deformity in Rheumatoid Arthritis: A Systematic Review

Background. Rheumatoid arthritis (RA) can cause deformity in particularly the craniocervical but also in the lower cervical region. Objectives. The aim of this study is to give an overview of current literature on the association of disease activity score (DAS) and the prevalence and progression of rheumatoid arthritis-associated cervical spine deformities. Methods. A literature search was done in PubMed, Embase, and Web of Science using a sensitive search string combination (Supplemental File). Studies describing the association between DAS and the incidence and progression of atlantoaxial subluxation, vertical subluxation, and subaxial subluxation were selected by predefined selection criteria, and risk of bias was assessed using a Cochrane checklist adjusted for this purpose. Results. Twelve articles were retrieved, and risk of bias on study level was low to moderate. In the eight longitudinal studies, patients demonstrated high DAS at baseline, which decreased upon treatment with medication: cervical deformity at the end of follow-up was associated with higher DAS values. The four cross-sectional studies did not demonstrate a straightforward correlation between DAS and cervical deformity. Deformity progression was evaluated in three studies, but no convincing association with DAS was established. Conclusion. A positive association between prevalence of cervical spine deformities and high disease activity was demonstrated, but quality of evidence was low. Progression of cervical deformity in association with DAS control over time is only scarcely studied, and future investigations should focus on halting of deformity progression.

Mapping of Venous Sinus Anatomy and Occipital Bone Thickness for Safe Screw Placement in 100 Patients with 46,200 Standardized Measurements Using Computed Tomography Angiography

STUDY DESIGN

Retrospective descriptive study.

OBJECTIVE

The aim of this study was to create topographical maps of occipital bone thickness and venous sinus (VS) presence to assess the risks of screw insertion in four commercially available occipital plates.

SUMMARY OF BACKGROUND DATA

Craniocervical junction instability and deformity are serious pathological conditions that require posterior fixation of the occipital bone to the cervical vertebrae. Insertion of occipital bone screws requires evaluation of both occipital bone thickness for effective internal fixation and intracranial VS presence for vascular injury prevention. Despite the surgical risks, there is a paucity of research on safe screw placement.

METHODS

We created a matrix of 231 standardized measurement points to analyze the occipital bone thickness and VS presence in cervical spine CT angiograms. These measurements were used to create topographical maps of occipital bone thickness and likelihood of VS presence, which we then compared to the screw hole configurations of four occipital plates.

RESULTS

Hundred patients were assessed. Maximum occipital bone thickness of 13.9 ± 3.3 mm was midline in the occipital bone, 45 mm from the foramen magnum, around the external occipital protuberance (EOP). Regions with thicknesses >8 mm were 2 cm lateral to the EOP at the level of the superior nuchal line and 2.5 cm inferior to the EOP. The area with the highest VS presence rate was around the EOP and the superior nuchal line. The right transverse VS was more prominent in both sexes.

CONCLUSION

There is a limited area of the occipital bone with thicknesses for enough screw purchase. Previous studies have shown 8 mm as the minimum screw length to reduce the risk of implant failure. In our analysis, only "T"-shaped plates had configurations with thicknesses >8 mm for each screw hole. For every screw hole in the analyzed occipital plates, there was a possibility of VS presence ranging from 8% to 33%.Level of Evidence: 5.

The Feasibility of Anterior Occipital Condyle Screw for the Reconstruction of Craniovertebral Junction: A Digital Anatomical and Cadaveric Study of a Novel Technique

Background

Anterior occipital condyle screw (AOCS) could be a feasible alternative technique for occipitocervical fusion for reconstruction of craniovertebral junction. This study aimed to analyze the feasibility of AOCS.

Methods

The craniovertebral junction computed tomography (CT) scans of 40 adults were enrolled and imported into Mimics software. Then, the three-dimensional reconstruction digital model of craniovertebral junction was established to determine entry point, insertion angle, and screw’s trajectory. After AOCS insertion into ten human cadaver spine specimens, CT scans were performed to verify the location between screws and important structures.

Results

The optimal entry point was located caudally and medial to the ventral of occipital condyle. The optimal trajectory was in inclination angle (5.9°±3.4°) in the sagittal plane and divergence angle (26.7°±6.0°) in the axial plane with the screw length around 21.6±1.2mm. None of the screws invaded the hypoglossal canal and vertebral artery in any of the specimens.

Conclusion

AOCS fixation is a feasible, novel technique for anterior craniovertebral junction reconstruction, and it could be an effective alternative operation for anterior reconstruction with titanium mesh cage.

Is it Suitable to Fix the Occipito-C2 Angle and the Posterior Occipitocervical Angle in a Normal Range During Occipitocervical Fusion?

STUDY DESIGN

This is a retrospective study.

OBJECTIVES

The objective of this study was (1) to measure the occipito-C2 angle (OC2A) and the posterior occipitocervical angle (POCA) in a normal population, and (2) to observe the effects of OC2A and POCA selection on postoperative clinical efficacy and lower cervical curvature after occipitocervical fusion (OCF) in patients with basilar invagination (BI) and atlantoaxial fracture and dislocation (AAFD).

SUMMARY OF BACKGROUND DATA

OC2A has received special attention with respect to the clinical efficacy during OCF. However, none of studies have focused on the relationship between OC2A and POCA and have assessed their impact on clinical outcomes in patients with different occipiocervical diseases.

MATERIALS AND METHODS

One hundred fifty healthy subjects without any cervical disease (healthy group) were randomly selected based on sex and age. Three spine surgeons measured the OC2A and POCA in the healthy group and averaged the values. Forty-two patients with BI (BI group) and 32 patients with AAFD (AAFD group) who underwent OCF between January 2012 and January 2017 were reviewed. OC2A, POCA, and cervical spinal angle (CSA) were measured preoperatively, postoperatively immediately after surgery and ambulation, and at the final follow-up visit. The preoperative and final follow-up visual analog scale (VAS), Japanese Orthopaedic Association score (JOA), neck disability index (NDI), and the change of CSA from postoperatively immediately after surgery and ambulation to the final follow-up (dCSA) were recorded.

RESULTS

The values of OC2A and POCA were 14.5±3.7 and 108.2±8.1 degrees in the healthy group, respectively, and the respective 95% confidence intervals were 7.2-21.8 and 92.3-124.0 degrees as the normal range. There was a negative correlation between OC2A and POCA (r=-0.386, P<0.001). The preoperative value of OC2A (5.6±4.3 degrees) in BI group was smaller than that in the healthy group (P<0.05); however, the preoperative value of POCA (123.0±10.4 degrees) in the BI group was larger than that in the healthy group (P<0.05). There was no significantly different of OC2A and POCA between the healthy group and the AAFD group before the operation (P>0.05). The preoperative value of CSA (25.7±9.5 degrees) in the BI group was larger than that in the AAFD group (16.5±5.1 degrees) (P<0.05). In the BI group, 26 patients had ideal OC2A and POCA (both within 95% confidence interval of the healthy group) postoperatively immediately after surgery and ambulation as a subgroup of the ideal angle group. In the remaining patients with BI (nonideal angle group), VAS, JOA, and NDI at the final follow-up were significantly better than those in the ideal angle group (P<0.05). The ideal angle group showed statistically greater dCSA than the nonideal angle group of the BI group (P<0.05). On the contrary, in the AAFD group, the NDI in the ideal angle group (20 patients) was better than that in the nonideal angle group at the final follow-up, and the ideal angle group had a smaller dCSA compared with the nonideal angle group (P<0.05).

CONCLUSIONS

The biomechanical balance of occipitocervical region in patients with occipitocervical diseases with different pathogenesis is different. On the basis of the different types of occipitocervical diseases, an appropriate range of OC2A and POCA should be selected by the surgeon during OCF, which can further improve the clinical efficacy and reduce the loss of the lower cervical curvature after surgery.

Importance of the Occipitoaxial Angle and Posterior Occipitocervical Angle in Occipitocervical Fusion

OBJECTIVE

To observe the effects of occipitoaxial angle (O-C2 angle, OC2A) and posterior occipitocervical angle (POCA) selection on postoperative clinical efficacy and lower cervical curvature in patients with acute acquired atlantoaxial dislocation after occipitocervical fusion (OCF).

METHODS

A total of 150 healthy subjects without cervical disease (healthy group) were randomly selected based on gender and age. Three spine surgeons measured the OC2A and POCA of the healthy group and averaged the values. A total of 30 patients with an average age of 51.0 years (range, 18-70 years; 16 male and 14 female) with trauma or rheumatoid arthritis (disease group) who underwent occipitocervical fusion (OCF) for atlantoaxial dislocation between January 2012 and June 2016 were reviewed. OC2A, POCA, and cervical spinal angle (CSA) were measured postoperative/soon after surgery and ambulation, and at the final follow-up visit. The preoperative and final follow-up visual analog scale (VAS), Japanese orthopedics association score (JOA), neck disability index (NDI), and dCSA (change of CSA from postoperative/soon after surgery and ambulation to final follow-up) were recorded.

RESULTS

The values of OC2A and POCA in 150 healthy subjects were 14.5° ± 3.7° and 108.2° ± 8.1°, respectively, and the 95% confidence interval (CI) were 7.2°-21.8° and 92.3°-124.0°, respectively. There was a negative correlation between OC2A and POCA (r = -0.386, P < 0.001). There were 18 patients (group one) of ideal OC2A and POCA (both within 95% CI of the healthy group) postoperative/soon after surgery and ambulation with a mean follow-up time of 26.3 ± 20.9 months in disease group. The remaining patients (group two) with a mean follow-up time of 31.3 ± 21.3 months. There was no statistically significant difference in the baseline data as well as pre-operative outcomes, including VAS score, JOA score, and NDI between the two groups. Likewise, the post-operative outcomes in final follow-up, including VAS and JOA score, had no distinct difference in the two groups. However, NDI (11.0 ± 2.9) in group two at the final follow-up was significantly higher than that in group one (7.0 ± 2.3) (P < 0.001). And group two showed statistically greater dCSA (5.9 ± 7.5°) than group one (-2.3° ± 6.2°) (P = 0.003).

CONCLUSIONS

The negative correlation between OC2A and POCA plays an important role in maintaining the biodynamic balance of the occipital-cervical region. OC2A and POCA should be controlled of a normal population in patients with acute acquired atlantoaxial dislocation during OCF, which can further improve the clinical efficacy and prevent loss of lower cervical curvature after surgery.

Occipital and external acoustic meatus to axis angle: a useful predictor of oropharyngeal space in rheumatoid arthritis patients with atlantoaxial subluxation

OBJECTIVE

Dyspnea and/or dysphagia is a life-threatening complication after occipitocervical fusion. The occiput-C2 angle (O-C2a) is useful for preventing dyspnea and/or dysphagia because O-C2a affects the oropharyngeal space. However, O-C2a is unreliable in atlantoaxial subluxation (AAS) because it does not reflect the translational motion of the cranium to C2, another factor affecting oropharyngeal area in patients with rheumatoid arthritis (RA) who have reducible AAS. The authors previously proposed the occipital and external acoustic meatus to axis angle (O-EAa; i.e., the angle made by McGregor's line and a line joining the external auditory canal and the middle point of the endplate of the axis [EA line]) as a novel, useful, and powerful predictor of the anterior-posterior narrowest oropharyngeal airway space (nPAS) distance in healthy subjects. The aim of the present study was to elucidate the validity of O-EAa as an indicator of oropharyngeal airway space in RA patients with AAS.

METHODS

The authors investigated 64 patients with RA. The authors collected lateral cervical radiographs at neutral position, flexion, extension, protrusion, and retraction and measured the O-C2a, C2-C6, O-EAa, anterior atlantodental interval (AADI), and nPAS. Patients were classified into 2 groups according to the presence of AAS and its mobility: group N, patients without AAS; and group R, patients with reducible AAS during dynamic cervical movement.

RESULTS

Group N had a significantly lower AADI and O-EAa than group R in all but the extension position. The O-EAa was a better predictor for nPAS than O-C2a according to the mixed-effects models in both groups (marginal R2: 0.510 and 0.575 for the O-C2a and O-EAa models in group N, and 0.250 and 0.390 for the same models, respectively, in group R).

CONCLUSIONS

O-EAa was superior to O-C2a in predicting nPAS, especially in the case of AAS, because it affects both O-C2a and cranial translational motion. O-EAa would be a useful parameter for surgeons performing occipitocervical fusion in patients with AAS.

Revision surgery after rod breakage in a patient with occipitocervical fusion: A case report

RATIONALE

Rod breakage after occipitocervical fusion (OCF) has never been described in a patient who has undergone surgery for basilar invagination (BI) and atlantoaxial dislocation (AAD). Here, we present an unusual but significant case of revision surgery to correct this complication.

PATIENT CONCERNS

A 32-year-old female presented with neck pain, unstable leg motion in walking, and also BI with AAD. Her first surgery was planned to correct these conditions and for fusion at the occipital junction (C3-4) using a screw-rod system. At the 31-month follow-up after her first operation, the patient complained of severe neck pain and limitation of motion, suggesting rod breakage.

DIAGNOSES

Rod breakage after occipitocervical fusion for BI and AAD.

INTERVENTIONS

The patient underwent reoperation for replacement of the broken rods, adjustment of the occipitocervical angle, maintenance of the bone graft bed, and fusion.

OUTCOMES

At follow-up, the hardware was found to be in good condition, with no significant loss of cervical lordosis. At the 37-month follow-up after her second operation, the patient was doing better and continuing to recover.

LESSONS

We concluded that nonideal choice of occipitocervical angle may play an important role in rod breakage; however, an inadequate bone graft and poor postoperative fusion may also contribute to implant failure.

The Prediction and Prevention of Dysphagia After Occipitospinal Fusion by Use of the S-line (Swallowing Line)

STUDY DESIGN

Clinical case series and risk factor analysis of dysphagia after occipitospinal fusion (OSF).

OBJECTIVE

The aim of this study was to develop new criteria to avoid postoperative dysphagia by analyzing the relationship among the craniocervical alignment, the oropharyngeal space, and the incidence of dysphagia after OSF.

SUMMARY OF BACKGROUND DATA

Craniocervical malalignment after OSF is considered to be one of the primary triggers of postoperative dysphagia. However, ideal craniocervical alignment has not been confirmed.

METHODS

Thirty-eight patients were included. We measured the O-C2 angle (O-C2A) and the pharyngeal inlet angle (PIA) on the lateral cervical radiogram at follow-up. PIA is defined as the angle between McGregor's line and the line that links the center of the C1 anterior arch and the apex of cervical sagittal curvature. The impact of these two parameters on the diameter of pharyngeal airway space (PAS) and the incidence of the dysphagia were analyzed.

RESULTS

Six of 38 cases (15.8%) exhibited the dysphagia. A multiple regression analysis showed that PIA was significantly correlated with PAS (β = 0.714, P = 0.005). Receiver-operating characteristic curves showed that PIA had a high accuracy as a predictor of the dysphagia with an AUC (area under the curve) of 0.90. Cases with a PIA less than 90 degrees showed significantly higher incidence of dysphagia (31.6%) than those with a 90 or more degrees of PIA (0.0%) (P = 0.008).

CONCLUSION

Our results indicated that PIA had the high possibility to predict postoperative dysphagia by OSF with the condition of PIA <90°. Based on these results, we defined "Swallowing-line (S-line)" for the reference of 90° of PIA. S-line (-) is defined as PIA <90°, where the apex of cervical lordosis protruded anterior to the "S-line," which should indicate the patient is at a risk of postoperative dysphagia.

LEVEL OF EVIDENCE

4.

Three-dimensional finite element analysis of a newly developed aliform internal fixation system for occipitocervical fusion

For patients with occipital malformation, it is difficult to obtain reliable stability using three screws on the midline. A new aliform occipitocervical internal fixation system was designed. The occiput was fixed with 3, 7, or 11 screws, and a three-dimensional finite element model of the system was established. A compressive preload of 40N combined with a pure moment of 1.5Nm was applied to simulate normal flexion, extension, lateral bending, and axial rotation. The stress distribution across the screws on the occiput and the occipital displacement produced by the newly developed system were compared with those produced by the DePuy SUMMIT system. Compared with the SUMMIT system (control group), in the new system, the maximum stress on the occiputs fixed with 3 screws (group A) and 7 screws (group B) increased by 16.5% and 15.0%, respectively. In contrast, the maximum stress on the occiput fixed with 11 screws (group C) decreased by 15.6%. In addition, the maximum occipital displacements under extension decreased by 10.0%, 11.4%, and 11.8% in the A, B, and, C groups, respectively. Our results indicate that both group A and the control group exhibited sufficient strength and instant stability; however, group C exhibited the highest stability and the lowest maximum von Mises stress.

Sagittal Alignment of Spine and Spinal Cord for Upper Cervical Irreducible Atlantoaxial Kyphosis in Elderly Patients

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate clinical and radiographic outcome of posterior decompression and occipito-cervical/thoracic (OCT) fusion in patients with irreducible atlantoaxial kyphosis (IAK).

SUMMARY OF BACKGROUND DATA

Posterior OCT fusion is an effective surgical procedure for treating IAK in the elderly. However, it is unclear whether correction can be obtained by the strong corrective force provided by implants, even in patients in whom reduction cannot be obtained preoperatively. There are no reports of improvement in patients in whom correction could not be achieved by a rigid system.

METHODS

Twenty-five patients with IAK with mild vertical subluxation due to rheumatoid arthritis and 3 patients with IAK due to os odontoideum were treated with fossa magnum decompression, C1 laminectomy and OCT fusion.

RESULTS

Mean follow-up period was 4.2 years. Preoperative and postoperative neurological findings revealed improvement by 1 or more grades in 18 of 28 (64.2%) patients. The parameters of spinal alignment, sagittal spinal cord alignment, and basilar invagination were evaluated on radiographs. No significant difference between preoperative and postoperative status was seen for the clivo-axial angle, occipito-upper cervical angle, atlantodental interval, or occipito-cervical 2 angle, whereas significant improvement was seen in the cervico-medullary and dorsal CM angles (both P<0.05). No significant postoperative change in the vertical direction was seen for any of the parameters. Width of the spinal cord at the C1 level was significantly increased postoperatively, with a significant expansion of the cerebral spinal fluid space at the same level (P<0.05).

CONCLUSIONS

Posterior decompression with fusion for the treatment of IAK in the elderly did not produce significant change in spinal alignment, but did significantly improve spinal cord alignment and local spinal cord compression at the C1 level, achieving satisfactory clinical outcomes.

Distal Junctional Disease after Occipitothoracic Fusion for Rheumatoid Cervical Disorders: Correlation with Cervical Spine Sagittal Alignment

Study Design Retrospective radiographic study. Objective We have performed occipitothoracic (OT) fusion for severe rheumatoid cervical disorders since 1991. In our previous study, we reported that the distal junctional disease occurred in patients with fusion of O-T4 or longer due to increased mechanical stress. The present study further evaluated the association between the distal junctional disease and the cervical spine sagittal alignment. Methods Among 60 consecutive OT fusion cases between 1991 and 2010, 24 patients who underwent O-T5 fusion were enrolled in this study. The patients were grouped based on whether they developed postoperative distal junctional disease (group F) or not (group N). We measured pre- and postoperative O-C2, C2-C7, and O-C7 angles and evaluated the association between these values and the occurrence of distal junctional disease. Results Seven (29%) of 24 patients developed adjacent-level vertebral fractures as distal junctional disease. In group F, the mean pre- and postoperative O-C2, C2-C7, and O-C7 angles were 12.1 and 16.8, 7.2 and 11.2, and 19.4 and 27.9 degrees, respectively. In group N, the mean pre- and postoperative O-C2, C2-C7, and O-C7 angles were 15.9 and 15.0, 4.9 and 5.8, and 21.0 and 20.9 degrees, respectively. There were no significant differences between the two groups. The difference in the O-C7 angle (postoperative angle - preoperative angle) in group F was significantly larger than that in group N (p = 0.04). Conclusion Excessive correction of the O-C7 angle (hyperlordotic alignment) is likely to cause postoperative distal junctional disease following the OT fusion.

Mapping occipital bone thickness using computed tomography for safe screw placement

OBJECT Safe and effective insertion of occipital bone screws requires morphological analysis of the occipital bone, which is poorly documented in the literature. The authors of this study present morphological data for determining the area of screw placement for optimal internal fixation. METHODS The subjects of this institutional review board-approved retrospective study were 105 individuals without head and neck disease who underwent CT imaging at the authors' hospital. There were 55 males and 50 females, with a mean age of 57.1 years (range 20-91 years). Measurements using CT were taken according to a matrix of 55 points following a grid with 1-cm spacing based on the external occipital protuberance (EOP). RESULTS The maximum thickness of the occipital bone was at the level of the EOP at 16.4 mm. Areas with thicknesses > 8 mm were more frequent at the EOP and up to 2 cm in all directions, as well as up to 1 cm in all directions at a height of 1 cm inferiorly, and up to 3 cm from the EOP inferiorly. The male group tended to have a thicker occipital bone than the female group, and the differences were significant around the EOP. The ratio of the trabecular bone to the occipital bone thickness was > 30% in the central region. At positions more than 2 cm laterally, the ratio was < 15%, and the ratio gradually decreased further laterally. CONCLUSIONS Screws that are 8 mm long can be placed in the area extending 2 cm laterally from the EOP at the level of the superior nuchal line and approximately 3 cm inferior to the center. These results suggest that it may be possible to effectively insert a screw over a wider area than the conventional reference range.

Evaluation of occipitocervical neutral position using lateral radiographs

Background

Intraoperative assessment of neutral occipitocervical balance during a fusion procedure is challenging. We designed this study to introduce a more comprehensive method of evaluating the occipitocervical neutral position using lateral radiographs.

Methods

One hundred neutral lateral cervical spine radiographs interpreted as normal were studied. Cervical spine radiographs were performed using a standard technique. The occipitocervical angle, the occipitocervical distance, and the mandible cervical distance were measured by different observers.

Results

A difference analysis was performed between males and females. The mean mandible cervical distances were 11.0 and 11.2 mm in males and females, respectively. The mean occipitocervical distances were 22.0 mm (male) and 19.6 mm (female), and the occipitocervical angles were 47.2° (male) and 45.5° (female). The occipitocervical distance revealed significant differences between males and females (p <0.01). However, there were no significant differences between sexes for the occipitocervical angle or the mandible cervical distance (p >0.01).

Conclusions

This study offers reference values for the occipitocervical angle and occipitocervical distance for the estimation of the occipitocervical neutral position. The introduction of the mandible cervical distance may make the evaluation more direct and more comprehensive during surgery because of its sensitivity to changes in head position.

Correlation of posterior occipitocervical angle and surgical outcomes for occipitocervical fusion

Study Type Retrospective cohort study.

Introduction Craniocervical instability is a surgical disease, most commonly due to rheumatoid arthritis, trauma, erosive pathologies such as tumors and infection, and advanced degeneration. Treatment involves stabilization of the craniovertebral junction by occipitocervical instrumentation and fusion. However, the impact of the fixed occipitocervical angle on surgical outcomes, in particular the need for revision surgery and the incidence of dysphagia, remains unknown. Occipitocervical fusions (OCFs) at a single institution were reviewed to evaluate the relationships between postoperative neck alignment, the need for revision surgery, and dysphagia.

Objective The objective of this study is to determine whether an increased posterior occipital cervical angle results in an increase in the need for revision surgery, and secondary, dysphagia.

Methods A retrospective review of spinal surgery patients from January 2007 to June 2013 was conducted searching for patients who underwent an occipitocervical instrumented fusion utilizing diagnostic and procedural codes. Specifically, a current procedural code of 22590 (arthrodesis, posterior technique [craniocervical]) was queried, as well those with a description of “craniocervical” or “occipitocervical” arthrodesis. Ideal neck alignment before rod placement was judged by the attending surgeon. A review of all cases for revision surgery or evidence of dysphagia was then conducted.

Results From January 2007 to June 2013, 107 patients were identified (31 male, 76 female, mean age 63). Rheumatoid arthritis causing myelopathy was the most common indication for OCF, followed by trauma. Twenty of the patients were lost to follow-up and seven died within the perioperative period. Average follow-up for the remaining 80 patients was 16.4 months. The mean posterior occipitocervical angle (POCA), defined as the angle formed by the intersection of a line drawn tangential to the posterior aspect of the occipital protuberance and a line determined by the posterior aspect of the facets of the third and fourth cervical vertebrae, calculated after stabilization, was 107.1 degrees (range, 72–140 degrees). Reoperation was required in 11 patients (11/107, 10.3%). The mean POCA for the reoperation group was 109.5 degrees (range, 72–123) and was not significantly different than patients not requiring reoperation (106.5, p > 0.05). However, for all pathologies excluding infection as a cause for reoperation, the mean POCA was significantly higher, 115.14 degrees (p = 0.039) (Table 1). Seven patients (6.5%) complained of dysphagia postoperatively with a significantly higher POCA of 115 degrees (p = 0.039). Of these seven patients, six underwent posterior-only procedures. One patient underwent anterior and posterior procedures for a severe kyphotic deformity. The dysphagia resolved in six patients over a mean of 3 weeks (range, 2–4 weeks). One patient, whose surgery was posterior only, required the insertion of a gastrostomy tube.

Conclusions An elevated POCA may result in need for reoperation due to increased biomechanical stress upon adjacent segments or the construct itself due to flexion in an attempt to maintain forward gaze. Further, an elevated POCA seems to also correlate with a higher incidence of dysphagia. Further investigation is necessary to determine the ideal craniocervical angle which is likely individualized to a particular patient based on global and regional spinal alignments.

Adjacent-level failures after occipito-thoracic fusion for rheumatoid cervical disorders

INTRODUCTION

The natural history of cervical spine lesions in rheumatoid arthritis (RA) is variable. We have actively performed occipito-thoracic fusion for severe destructive rheumatoid cervical disorders and reported its clinical results and complications. In our previous study, the most frequent complication was the adjacent-level failures caused by the fragile spine. The objective of this study was to determine risk factors for adjacent-level failures after occipito-thoracic fusion.

MATERIALS AND METHODS

Subjects were 35 RA patients (31 females and 4 males) who underwent occipito-thoracic fusion using RRS Loop Spinal System(®) (Robert Reid Inc. Tokyo, Japan), and the incidence and characteristics of adjacent-level failures were investigated. Furthermore, the adjacent-level failures were divided into two types according to their levels, fracture at the lowest level of the fusion area and that at the level inferior to the fusion area, and the characteristics of each type were evaluated.

RESULTS AND CONCLUSION

Nine (26%) of 35 patients suffered adjacent-level failures (10 vertebral fractures). Adjacent-level failures occurred when the distance of fixation was "O-T4" or longer. The long fusion might cause adjacent-level failures due to greater mechanical stress. Seven fractures occurred at the lowest level of the fusion area, and all of them were cured without symptoms by conservative treatment. Three fractures occurred at the level inferior to the fusion area, and one of them needed additional surgery due to sudden paraplegia resulting from collapse of the adjacent vertebra. After occipito-thoracic fusion, burst fractures at the level inferior to the fusion area might cause sudden paraplegia, and therefore a careful observation should be required for patients with these fractures.

Cervical spine instability in rheumatoid arthritis

Rheumatoid arthritis (RA) is the most common inflammatory disease of the cervical spine (CS). After hands and feet, CS is the most commonly involved segment, being present in more than half of the patients with RA. Especially in the CS, RA may cause degeneration of ligaments, leading to laxity, instability and subluxation of the vertebral bodies. This is often asymptomatic or symptoms are erroneously attributed to peripheral manifestations. Otherwise, this may cause compression of spinal cord (SC) and medulla oblongata leading to severe neurologic deficits and even sudden death. Owing to its potentially debilitating and life-threatening sequelae, inevitable progression once neurologic deficits occur and the poor medical condition of afflicted patients, CS involvement remains a priority in the diagnosis and its treatment will remain a challenge. The surgical approach aims a solid fixation of the upper cervical spine, giving stability, preventing neurologic deterioration and injury to the SC, leading to improved neurologic function, vascular integrity and maintenance of sagittal balance. The recent advances in surgical techniques, complete understanding of the anatomy and precise preoperative evaluation led to safer and more effective procedures that have decreased complication rates. Based on the fact that when a patient becomes myelopathic the rate of long-term mortality increases and the chance of neurologic recovery decreases, many authors agree that early surgical intervention, before the onset of neurologic deficits, gives a more satisfactory outcome. However, the timing when a prophylactic stabilization should occur is poorly defined, and so, patients with radiographic instability but without evidence of neurologic deficit are still the most difficult to manage.

Is inclusion of the occiput necessary in fusion for C1-2 instability in rheumatoid arthritis?

OBJECT

The atlantoaxial joint is the location most and earliest affected in patients with rheumatoid arthritis (RA). In longstanding disease, ligamentous and osseous destruction can progress and involve all cervical segments. If surgical intervention is necessary, some prefer, to be safe, undertaking fusion to the occiput, whereas others advocate 1-level fusion of C1-2. Sparing the occiput (Oc)-C1 segment would allow retention of a considerable amount of physiological range of motion and seems beneficial against subaxial overload. Previous clinical studies on this topic have provided only nonspecific data after short-term follow-up, rendering a segment-sparing approach questionable. The purpose of the present investigation was to assess long-term progression of inflammatory or degenerative destruction in the Oc-C1 segment after isolated C1-2 fusion for RA.

METHODS

In a series of 113 consecutive patients with RA-related destruction restricted to the craniocervical junction, 14 individuals underwent Oc-C2 fusion and 99 underwent surgery exclusively at the C1-2 level. After a mean follow-up period of 9.4 years (range 4.9-14.7 years), 46 patients were available for clinical and radiographic examination, including CT imaging.

RESULTS

None of the 46 patients needed additional surgery to extend the fusion to the occiput. Despite marked deterioration in the subaxial cervical spine, in general there were little or no changes in the atlantooccipital region. All but one patient presented with bony fusion of the fixed C1-2 level at follow-up.

CONCLUSIONS

The results of this investigation suggest that if the Oc-C1 joint is free of osseous destructions on conventional radiographs and free of abnormalities on MRI scans at the time of surgery (for transarticular fixation and fusion of C1-2), there is a very low risk for relevant destruction in the following 5-14 years. Thus, no prophylactic oligosegmental approach, but rather a segment-sparing monosegmental approach, is preferred, even in patients with high inflammatory levels.

Occipitocervical fusion in elderly patients

BACKGROUND

Occipitocervical disease (OCD) in elderly patients will become increasingly common as the population ages. Our experience with occipitocervical fusions (OCF) in this population suggests mixed outcomes.

METHODS

Twenty consecutive patients over 65 years old underwent OCF between 1995 and 2005. A retrospective review of demographic, presentation, surgical and outcome data was performed.

RESULTS

Twenty patients averaging 75.3 years of age (range 65 to 91) were identified. All patients had evidence of myelopathy; however, the primary surgical indications were progressive spinal cord dysfunction (15), brainstem compression (3), and pain (2). Surgical approach was isolated posterior (9), or anterior transoral odontoidectomy followed by posterior stabilization (11). Overall, surgery improved function modestly; average modified Japanese Orthopedic Association functional score (improved 0.9 grades), average Ranawat Myelopathy Score (improved 0.4 grades), and average Nurick Myelopathy Grade (improved 0.6 grades). However, patients with poor preoperative functional assessment (Ranawat grade ≥ III) had greater neurologic improvement than those with good preoperative function, measured by Nurick grade improvement (1 vs. -0.28; P = .03) and Ranawat grade improvement (0.7 vs. -0.2; P = .03). Additionally, the posterior approach demonstrated significant improvement in Japanese Orthopedic Association functional assessment over patients with anterior/posterior approaches (2.2 vs. -0.3; P = .03), with fewer complications (posterior: 1 minor; anterior/posterior: 1 death, 2 major, 8 minor). Perioperative mortality occurred in 5%, and major morbidity in 10% of patients.

CONCLUSIONS

Preventing or stabilizing neurologic deficit in patients with OCD may require OCF, despite the patient's age. In the elderly population, our data favor using the posterior approach when possible, and demonstrate greater neurologic improvement in patients with poor preoperative function.

Treatment of irreducible old atlantoaxial subluxation with cable-dragged reduction and cantilever beam internal fixation

STUDY DESIGN

Retrospective case series study of surgical outcome for 21 atlantoaxial subluxation patients treated with a new technique, called cable-dragged reduction/cantilever beam internal fixation. Surgery was performed by a single surgeon.

OBJECTIVE

To describe and evaluate the cable-dragged reduction/cantilever beam internal fixation technique for the treatment for old atlantoaxial subluxation irreducible by traction.

SUMMARY OF BACKGROUND DATA

Management of old atlantoaxial subluxation has always been a difficult task. A more effective way to achieve surgical reduction is needed.

MATERIALS AND METHODS

Twenty one patients, aged 31.6 ± 13.3 years (range, 11-67 years), 17 men and four women, with atlantoaxial subluxation that failed to be reduced after 10 to 111 days in traction, underwent posterior cable-dragged reduction/cantilever beam internal fixation surgery. Frankel classification of neural function before surgery was the following: Frankel B, four patients; Frankel C, five patients; Frankel D, four patients; and Frankel E, eight patients. Plain radiographs, computed tomographic three-dimensional reconstructive images and magnetic resonance images of the cervical spine were obtained at 3, 6, and 12 months after surgery, and each year thereafter. No patient was lost to follow-up, and the follow-up time ranged from 6 months to 4 years. Rate of reduction and C1∼3 fusion, as well as improvement of neural function, were recorded and analyzed.

RESULTS

The average follow-up period was 13.2 months. Radiographic evaluation of the group at follow-up showed 16 complete and five partial reductions, and satisfactory decompression and C1∼3 fusion in all cases. Neural function at the end of the follow-up was Frankel B still in one patient, Frankel C in seven patients, and Frankel E in 13 patients.

CONCLUSION

Cable-dragged reduction/cantilever beam internal fixation is almost as effective for reduction as anterior release but is less invasive and risky. It has similar operative time and blood loss to occipitocervical fusion but avoids arthrodesis of occipitoatlantal joint. It is also suitable for patients with severe myelopathy before surgery. Its major disadvantage is that C3, which is left free in the traditional atlantoaxial fusion surgery, has to be involved in fusion. And it is suitable only for patients with intact posterior arches in C1.

A systematic review of occipital cervical fusion: techniques and outcomes

Object

Numerous techniques have been historically used for occipitocervical fusion with varied results. The purpose of this study was to examine outcomes of various surgical techniques used in patients with various disease states to elucidate the most efficacious method of stabilization of the occipitocervical junction.

Methods

A literature search of peer-reviewed articles was performed using PubMed and CINAHL/Ovid. The key words “occipitocervical fusion,” “occipitocervical fixation,” “cervical instrumentation,” and “occipitocervical instrumentation” were used to search for relevant articles. Thirty-four studies were identified that met the search criteria. Within these studies, 799 adult patients who underwent posterior occipitocervical fusion were analyzed for radiographic and clinical outcomes including fusion rate, time to fusion, neurological outcomes, and the rate of adverse events.

Results

No articles stronger than Class IV were identified in the literature. Among the patients identified within the cited articles, the use of posterior screw/rod instrumentation constructs were associated with a lower rate of postoperative adverse events (33.33%) (p < 0.0001), lower rates of instrumentation failure (7.89%) (p < 0.0001), and improved neurological outcomes (81.58%) (p < 0.0001) when compared with posterior wiring/rod, screw/plate, and onlay in situ bone grafting techniques. The surgical technique associated with the highest fusion rate was posterior wiring and rods (95.9%) (p = 0.0484), which also demonstrated the shortest fusion time (p < 0.0064). Screw/rod techniques also had a high fusion rate, fusing in 93.02% of cases.

When comparing outcomes of surgical techniques depending on the disease status, inflammatory diseases had the lowest rate of instrumentation failure (0%) and the highest rate of neurological improvement (90.91%) following the use of screw/rod techniques. Occipitocervical fusion performed for the treatment of tumors by using screw/rod techniques had the lowest fusion rate (57.14%) (p = 0.0089). Traumatic causes of occipitocervical instability had the highest percentage of pain improvement with the use of screw/plates (100% improvement) (p < 0.0001).

Conclusions

Based on the existing literature, techniques that use screw/rod constructs in occipitocervical fusion are associated with very favorable outcomes in all categories assessed for all disease processes. For patients requiring occipitocervical arthrodesis for the treatment of inflammatory diseases, screw/rod constructs are associated with the most favorable outcomes, while posterior wiring and onlay in situ bone grafting is associated with the least favorable outcomes. Occipitocervical arthrodesis performed for the diagnosis of tumor is associated with the lowest rate of successful arthrodesis using screw/rod techniques, while posterior wiring and rods have the highest rate of arthrodesis. The nonspecified disease group had the lowest rate of surgical adverse events and the highest rate of neurological improvement.

Clinical output of the rheumatoid cervical spine in patients with mutilating-type joint involvement: for better activities of daily living and longer survival

STUDY DESIGN

Retrospective study.

OBJECTIVE

To gain an insight for the final clinical output of surgically managed cervical lesions in seropositive rheumatoid arthritis (RA) patients with mutilating-type joint involvement (mutilating-RA patients), these patients was followed up until either death or complete bedridden.

SUMMARY OF BACKGROUND DATA

There has been no study reporting the final clinical output of surgically managed cervical lesion in mutilating-RA patients. In our previous study, we reported short- to middle-term result of such patient. The present study further traced those patients and reports the final clinical output.

METHODS

Seventeen seropositive mutilating-RA patients extracted from 504 RA patients were enrolled. Eleven patients underwent surgical treatments, whereas six patients did not. All patients, who underwent operation, have received occipitocervical or occipitocervicothoracic fusion. Neck pain, neurological symptoms and ADL score were completely followed up (i.e., follow-up period>10 years).

RESULTS

The six patients of non-operated group worsened ADL score and resulted in either complete bedridden or death within 3 years. Contrary, 11 operated patients either improved or maintained ADL until their death. Survival rate in 6.2 years was 0% in non-operated group and 27% in operated group, respectively. The present study suggests that the seropositive mutilating-RA patients worsen cervical lesions once they become affected, and are likely to lose their ADL activity.

CONCLUSION

Once seropositive mutilating-RA patients develop major spinal involvement(s), they are likely to undergo a life-threatening stage of the disease during the next 5-10 years. Surgical intervention is advocated not only to treat the neurological compromise but also to sustain their ADL levels during end stage of disease. The sustained ADL, in turn, may contribute to the longevity of these patients by preventing other major life-threatening events.

Neurologic outcome of surgical and conservative treatment of rheumatoid cervical spine subluxation: a systematic review

OBJECTIVE

Rheumatoid arthritis commonly involves the upper cervical spine and can cause significant neurologic morbidity and mortality. However, there is no consensus on the optimal timing for surgical intervention: whether surgery should be performed prophylactically or once neurologic deficits have become apparent.

METHODS

A systematic review of the literature was performed to analyze neurologic outcome (Ranawat) and survival time (Kaplan-Meier) after surgical or conservative treatment using the MOOSE (Meta-analysis Of Observational Studies in Epidemiology) and GRADE (Grading of Recommendations, Assessment, Development and Evaluation system) criteria.

RESULTS

Twenty-five observational studies were selected. No randomized controlled trials (RCTs) could be found. All of the studies had a high risk of bias. Twenty-three studies reported the neurologic outcome after surgery for 752 patients. Neurologic deterioration rarely occurred in Ranawat I and II patients. Ranawat III patients did not fully recover. The 10-year survival rates were 77%, 63%, 47%, and 30% for Ranawat I, II, IIIA, and IIIB, respectively. The Ranawat IIIB patients had a significantly worse outcome. Another 185 patients treated conservatively were described in 7 studies. Neurologic deterioration rarely occurred in Ranawat I patients, but was almost inevitable in Ranawat II, IIIA, and IIIB patients. The Kaplan-Meier analysis showed a 10-year overall survival rate of 40%.

CONCLUSION

There are no RCTs that compared surgery with conservative treatment. In observational studies, surgical neurologic outcomes were better than conservative treatment in all patients with cervical spine involvement, and in asymptomatic patients with no neurologic impairment (Ranawat I) the outcomes were similar; however, the evidence is weak. Survival time of surgical and conservative treatment could not be compared.

Relevance of the cranioaxial angle in the occipitocervical stabilization using an original construct: a retrospective study on 50 patients

We present a retrospective study on a series composed of 50 patients, treated between 1992 and 2006, affected by pathologies of the craniocervical junction. All the patients were treated using an innovative procedure based on a cranial claw made up of low profile hooks, conceived by one of the authors. Advantages of this technique are, to our point of view, a higher resistance to cranial hooks dislodgment, when compared with screw fixation instrumentation, especially in pathological conditions, such as rheumatoid arthritis that leads to a qualitative deterioration of the bone stock and to the reduction of the occipital wall thickness. Occipitoaxial alignment was assessed radiographically using the McGregor line. We observed an improvement in the subjective evaluation of pain in all treated patients with a 46% improvement from the initial values. Moreover, patient stabilized with an occipitoaxial angle included in the physiological range showed better results either for the survival of the instrumentation or the onset of junctional pathology. Patients have been followed up afterwards and evaluated by the visual analogue scale for the assessment of pain and by the Nurick scale for the cases associated with myelopathy. We believe that cranial anchorage with a hook claw allows for an instrumentation provided with high stability, particularly useful in revision surgery and major instabilities. The study of the occipitoaxial angles showed that the better results and the long-lasting stability of the implant are correlated to a fusion angle included in the physiological range.

SURGICAL TREATMENT OF OCCIPITOCERVICAL INSTABILITY

OBJECTIVE

Instability of the occipitocervical junction can be a challenging surgical problem because of the unique anatomic and biomechanical characteristics of this region. We review the causes of instability and the development of surgical techniques to stabilize the occipitocervical junction.

METHODS

Occipitocervical instrumentation has advanced significantly, and modern modular screw-based constructs allow for rigid short-segment fixation of unstable elements while providing the stability needed to achieve successful fusion in nearly 100% of patients. This article reviews the preoperative planning, the variety of instrumentation and surgical strategies, as well as the postoperative care of these patients.

RESULTS

Current constructs use occipital plates that are rigidly fixed to the thick midline keel of the occipital bone, polyaxial screws that can be placed in many different trajectories, and rods that are bent to approximate the acute occipitocervical angle. These modular constructs provide a variety of methods to achieve fixation in the atlantoaxial complex, including transarticular screws or C1 lateral mass screws in combination with C2 pars, C2 pedicle, or C2 translaminar trajectories.

CONCLUSION

Surgical techniques for occipitocervical instrumentation and fusion are technically challenging and require meticulous preoperative planning and a thorough understanding of the regional anatomy, instrumentation, and constructs. Modern screw-based techniques for occipitocervical fusion have established clinical success and demonstrated biomechanical stability, with fusion rates approaching 100%.

Treatment of upper cervical spine involvement in rheumatoid arthritis patients

The cervical spine, especially the upper cervical spine, is a common focus of destruction by rheumatoid arthritis (RA). Because of its potentially debilitating and life-threatening sequelae, cervical spine involvement remains a priority in the diagnosis and treatment of RA. Many studies show that early surgical intervention gives a more satisfactory outcome. Surgery aims to establish spinal stability and to prevent neurological deterioration and injury to the spinal cord, leading to improved neurological function. The recent sophisticated screw-rod-plate technique allows one to obtain a solid fixation of the upper cervical spine with a high possibility of bone union even in RA patients. Although surgery of the occipitoatlantoaxial region is a challenge with many possibilities of serious complications, recent advances in the surgical technique, complete understanding of the anatomy, and precise preoperative evaluation have decreased complication rates. Early consultation with a specialized spine surgeon is mandatory once cervical involvement is suspected in an RA patient because once the patient becomes myelopathic, the rate of long-term mortality increases and the chance of neurological recovery decreases.

Endonasal endoscopic resection of the odontoid process in a nonachondroplastic dwarf with juvenile rheumatoid arthritis: feasibility of the approach and utility of the intraoperative Iso-C three-dimensional navigation

✓The authors report a case of a nonachnodroplastic dwarf with severe basilar invagination and compression of the cervicomedullary junction (CMJ) due to juvenile rheumatoid arthritis. Initially excellent reduction of the invagination and decompression of the CMJ was achieved using posterior fixation. However, 1 month postoperatively symptoms recurred and the authors found imaging evidence of recurrence as well. The patient subsequently underwent an endoscopic transnasal resection of the dens with assistance of Iso-C navigation. He recovered well and tolerated regular diet on postoperative Day 2.

Occipitocervical fusion with rigid internal fixation: long-term follow-up data in 69 patients

Object.

Instability of the occipitocervical junction may result from degenerative disease, infection, tumor, and trauma. Surgical stabilization involving screw fixation and rigid implants has been found to be biomechanically superior to wire-based implants. To evaluate the long-term results in a large and diverse patient population, the authors prospectively studied a consecutive group of 69 patients.

Methods.

All patients underwent occipitocervical fusion in which rigid posterior instrumentation included either plates or rods and screws. Patients ranged in age from 11 to 90 years (mean 51.4 years); there were 34 female and 35 male patients. The mean follow-up duration was 37 months (range 6–66 months). Fifty-seven (83%) of the 69 patients had long-standing occipitocervical anomalies, whereas the remainder presented with acute instability. Basilar invagination was present in 20 patients.

Results.

Correction of a severe cervical kyphotic deformity was accomplished in six patients. There were no fatalities or medical complications associated with the procedures. During the follow-up period, 87% of the patients exhibited improvement in their myelopathic symptoms; in 13% the symptoms were unchanged. Complications were minimal. Stability was demonstrated on flexion/extension studies in all cases. There were no treatment-related deaths, although four patients died within the follow-up period, all due to progression of metastatic disease.

Conclusions.

The authors found that rigid internal fixation of the occipitocervical complex was safe, effective, and technically possible for spine surgeons familiar with occipital bone anatomy and lateral mass fixation.

Management of cervicomedullary compression in patients with congenital and acquired osseous–ligamentous pathologies

We present our experience in the diagnosis, surgical management and long-term follow-up of congenital and acquired osseous-ligamentous abnormalities or pathologies of the craniovertebral junction. The purpose of this study was: (i) to determine the incidence and degree of cervicomedullary compression in pediatric and young adult patients with congenital and acquired abnormalities, and (ii) to correlate cervicomedullary compression with other imaging and clinical factors to determine to what extend cervicomedullary compression is successfully treated with a posterior decompressive procedure, transoral decompression, and medical management. Between January 1995 and December 2004, 26 cases were managed in our department. These patients had: rheumatoid arthritis (RA) (3); traumatic injury (2); congenital basilar impression (5, in 2 cases a posteriorly oriented or retroflexed odontoid); infection (10); craniovertebral junction Pott's disease (9); os odonteideum (3); condylus tertius (1); and tumor (2). Six of the patients (23.1%) had syringomyelia. Only three (11.3%) were in the pediatric age group. Symptoms and signs included headache (72%), ataxia (38%), lower cranial nerve dysfunction (54%), quadriparesis (44%), hyperreflexia (76%), Hoffman positivity (72%), achilles clonus (72%) nystagmus (33%) and dysphagia (22%). The mean follow-up time was 44 months (range 3-85). Twelve (46.2%) had undergone posterior fossa decompression; seven (26.6%) had ventral decompression. Seven of the patients (26.6%) had medical management. The major morbidity included pharyngeal wound sepsis leading to dehiscence (3.8%), valopharyngeal insufficiency (3.8%), cerebrospinal fluid leakage (3.8%), postoperative macroglossia (3.8%) and inadequate anterior decompression (3.8%). Transient neurological deterioration occurred in two patients (7.6%). Our management paradigm will result in some neurologic improvements and limit the progression of symptoms. Patients with these pathologies are likely to show a good neurologic outcome when treatment, whether with or without surgery, is administered early in the course of the disease.

Complex Deformities of the Cervical Spine

Cervical deformities arise from a multitude of causes, including genetic, congenital, inflammatory, degenerative, and iatrogenic etiologies. They often require surgical intervention for treatment of pain, progressive structural decompensation, and neurologic deterioration. Although congenital and hereditary causes of cervical deformity require specialized attention to particular clinical features and operative considerations, postsurgical (iatrogenic) cervical deformity after surgery is the most common single cause. Appropriate treatment involves careful selection of conservative and aggressive measures and familiarity with advanced surgical techniques that allow for the safe correction of these challenging deformities. Flexible deformities can be managed with single-staged procedures, whereas fixed deformities require two-staged or even three-staged procedures. Staged surgery for fixed cervical deformities can achieve up to 28 degrees of angular correction and 31% translational correction.

Long-term incidence of subaxial cervical spine instability following cervical arthrodesis surgery in patients with rheumatoid arthritis

OBJECTIVE

Cervical spine deformities are well-known complications of RA. A 5- to 20-year follow-up of 51 consecutive rheumatoid patients who underwent posterior cervical arthrodesis is presented to evaluate the recurrence of instability and need for further surgery.

METHODS

We conducted a retrospective review of the clinical features of 11 men and 40 women with an established diagnosis of RA and associated cervical deformities who underwent cervical spine surgery at the Mayo Clinic (Rochester, MN) between 1979 and 1990. Their mean age was 61 +/- 10 years (SD), and their duration of RA averaged 21 +/- 8.9 years (SD). There were 22 patients who presented with myelopathy, 7 with radiculopathy, and 22 with instability/neck pain. There were 33 patients with AAS, 2 with SMO process into the foramen magnum, 8 with SAS, and 8 with combinations of these. Preoperative reduction was followed by decompression and fusion using wiring techniques and autologous bone graft. Postoperative halo orthosis was provided for at least 3 months. The mean follow-up was 8.3 +/- 6 years (SD).

RESULTS

There were 31 patients (61%) who underwent atlantoaxial arthrodesis, 17 patients (33%) who underwent subaxial, and 3 patients (6%) who underwent occipitocervical arthrodesis. During follow-up, 39% (13/33) of patients with AAS developed nonsymptomatic (6) or symptomatic/unstable (7) SASs subsequent to C1-C2 fusion. The latter 7 patients (21%) subsequently required extension of their arthrodesis. Adjacent segment disease was most common at the C3-C4 interspace after atlantoaxial fusion in 62% (8/13). Among the 8 patients who underwent isolated cervical fusion for SAS, 1 patient (1/8, 12%) developed adjacent instability after a fall and required extension of the previous fusion. No secondary procedure was required for the 6 patients initially stabilized by C1-(C6-T1) fusions for combinations of AAS + SAS. None of the patients initially treated by C1-C2 arthrodesis for AAS progressed to SMO.

CONCLUSIONS

The incidence of subaxial instability in patients with rheumatoid disease who underwent cervical arthrodesis may be higher than previously reported, indicating the need for continued follow-up in these patients. Adjacent segment disease may be most common at the C3-C4 level following atlantoaxial fusion. Early stabilization of the C1-C2 complex in the patients with AAS may potentially prevent progression of SMO.

Surgical outcome in rheumatoid Ranawat Class IIIb myelopathy

OBJECTIVE

Rheumatoid arthritis frequently affects the craniovertebral junction (CVJ) and may lead to severe neck pain, quadriparesis, and respiratory dysfunction. Surgery in rheumatoid nonambulatory (Ranawat Class IIIb) patients carries a significant risk. This study presents the surgical outcome of Class IIIb patients with CVJ rheumatoid myelopathy and reviews the literature.

METHODS

One hundred twelve consecutive patients with rheumatoid cervical myelopathy underwent surgical decompression and stabilization. Thirty-two of the patients (mean age, 66.81 +/- 10.25 yr) with CVJ rheumatoid arthritis were in Class IIIb, and all had atlantoaxial subluxation. A halo brace was applied before surgery and continued during surgery. Eleven patients with reducible atlantoaxial subluxation underwent direct posterior fusion. Twenty-one patients with fixed atlantoaxial subluxation underwent transoral decompression and then posterior fusion while they were under anesthesia.

RESULTS

At a mean follow-up of 39 months, four patients improved to Class II and 14 improved to Class IIIa, whereas six remained in Class IIIb. Neck pain was relieved in all patients. There was one perioperative death after transoral surgery (posterior fusion not done), and seven other patients died subsequently of causes unrelated to surgery. The morbidity of surgery included construct failure, cerebrospinal fluid leak, superficial wound or graft donor site infection, transient dysphagia, and lung infection.

CONCLUSION

A large subset of patients with CVJ rheumatoid myelopathy may reach Class IIIb. These patients have unique management considerations. Surgery (despite high morbidity) often remains the best therapeutic option available to them. Improvement of even one grade in their Ranawat score from Class IIIb to Class IIIa brought about by surgery confers on them a significant benefit in terms of their quality of life and survival.

Occipitocervical fixation: long-term results

STUDY DESIGN

The study is a retrospective review of 58 patients who underwent occipitocervical fusion between 1997 and 2001.

OBJECTIVES

Our objective is to study the clinical results after occipitocervical fixation with long-term follow-up and assess factors contributing to clinical success.

METHODS

Data from patient charts, operative notes, physician office notes, and imaging studies were incorporated in the study. Myelopathy was assessed using a Nurick scale for preoperative and postoperative evaluation. Fusion was assessed using cervical plane films with flexion and extension views.

RESULTS

Mean follow-up was 36 months, with all patients having a greater than 1-year follow-up. The most common pathology was congenital cranial settling (41%) followed by trauma (22%) and rheumatoid arthritis (17%). Myelopathy was the most common presentation (62%) followed by pain (28%). A successful fusion occurred in 48 out of 51 patients (94%). Symptoms improved in 86% of patients, whereas 35% improved 1 Nurick grade. Complications occurred in 30% of patients. The cervical wound infection rate was 5%. The rate of adjacent level degeneration was 7%. The mortality rate was 1.7%.

CONCLUSIONS

Occipitocervical instrumentation allows for very high fusion rates without the need for halo vest immobilization. All patients with successful fixation have pain resolution. Myelopathy improves in most patients, whereas one-third of patients demonstrate dramatic improvement.

Rheumatoid arthritis: evaluation and surgical management of the cervical spine

BACKGROUND CONTEXT

Rheumatoid arthritis is a debilitating polyarthropathic degenerative condition. Eighty-six percent of patients with rheumatoid arthritis have cervical spine involvement. Often these lesions are clinically asymptomatic or symptoms are erroneously attributed to peripheral manifestation of the patient's rheumatoid disease. Because these lesions are common and missed diagnosis can result in death, early recognition is vital.

PURPOSE

The purpose of this literature review is to identify common lesions present in the rheumatoid neck and review diagnostic methods as well as treatment options for those requiring surgical intervention.

STUDY DESIGN

A review of the English medical literature with focus on more recent studies on the presentation, diagnosis, management, surgical treatment and clinical outcomes of rheumatoid arthritis of the cervical spine.

METHODS

A comprehensive literature review of the English medical literature obtained through Medline up to November 2003 was performed identifying relevant and more recent articles that addressed the presentation, evaluation, surgical management and outcomes of rheumatoid patients with cervical spine involvement.

RESULTS

If left untreated, a large percentage of rheumatoid patients with cervical spine involvement progress toward complex instability patterns resulting in significant morbidity and mortality. Once myelopathy occurs, prognosis for neurologic recovery and long-term survival is poor. In properly selected patients, anterior and/or posterior cervical procedures can prevent neurologic injuries and preserve remaining function.

CONCLUSION

Cervical spine involvement in the rheumatoid patient is common and progressive. Early diagnosis and treatment is imperative; however, surgical intervention should be considered carefully because associated morbidity and mortality is high.

Measurement of occipitocervical angle

STUDY DESIGN

This study compared the reliability of 3 techniques used to measure alignment between the occiput and cervical spine.

OBJECTIVES

Intraobserver and interobserver intraclass correlation coefficient were computed to determine the most reliable method to measure occipitocervical angle.

SUMMARY OF BACKGROUND DATA

No studies have been performed comparing occipitocervical angle measurement techniques.

METHODS

The angles between the inferior endplate of second cervical vertebrae and the occiput line using the Chamberlain line, McRae line, and McGregor line were measured from lateral cervical radiographs of 30 healthy volunteers. Five spine surgeons made measurements.

RESULTS

Mean intraobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.0 degrees (ranging from 0 degrees-15 degrees), 4.7 degrees (from 0 degrees-28 degrees), and 1.5 degrees (from 0 degrees-9 degrees), respectively; intraobserver intraclass correlation coefficients of the angles were 0.956, 0.835, and 0.975. Mean interobserver variances of the angles using Chamberlain line, McRae line, and McGregor line were 2.3 degrees (from 0.4 degrees-6.4 degrees), 5.0 degrees (from 1.8 degrees-11.9 degrees), and 1.4 degrees (from 0 degrees-4.5 degrees), respectively; interobserver intraclass correlation coefficients were 0.939, 0.802, and 0.972. The highest reliability indexes were obtained for McGregor line.

CONCLUSIONS

The McGregor line is the most reproducible and reliable method for measurement of the occipitocervical angle.

Reducción de las masas periodontoideas tras artrodesis posterior: revisión a propósito de 2 casos no vinculados a artritis reumatoide

Inflamatory periodontoid pannus is quite common in patients with rheumatoid arthritis. However, the occurrence of a pannus-like periodontoid mass that is unassociated with rheumatic inflammation is less frequent. Transoral surgery associated with a posterior stabilization has long been considered one of the most efficient methods to resolve the problem of instability in patients presenting neurological deficits secondary to the pannus. We present two cases of non rheumatic etiology, in which an occipito-cervical arthrodesis was used to resolve the proliferative lesion around the odontoid apophysis. Two women (67 and 60 years old respectively) presented symptoms of pain and neurological deterioration with an antecedent of possible past odontoid fracture in one case, and a previous large anterior cervical arthrodesis to correct spondylarthrosis in the other case. Both patient's neurological condition improved after placement of an arthrodesis through a posterior approach.

Inverted-hook occipital clamp system in occipitocervical fixation. Technical note

The authors describe an occipitocervical fixation procedure in which they use inverted occipital hooks inserted through a burr hole drilled in the squamous part of the occipital bone. Fifteen patients with unstable lesions of the occipitocervical junction underwent occipitocervical internal fixation. The mean follow-up period was 21 months (range 2-63 months). No implant failed, and postoperative immobilization was not required. The placement of a posterior occipitocervical graft (for which fusion is uncertain) can be avoided in certain conditions.