Outcomes of fusion for lateral atlantoaxial osteoarthritis: meta-analysis and review of literature

Athrodesis of the lateral atlanto-axial joint for the relief of neck pain and cervicogenic headache

BACKGROUND

Osteoarthrosis of the lateral atlanto-axial joint (LAAJ) may be a cause of upper neck pain and headache. Intra-articular injection of steroids may provide only short-lasting relief. For intractable pain, arthrodesis of the joint might be considered.

OBJECTIVE

To determine the success rates of arthrodesis of the lateral atlanto-axial joint for relieving neck pain and disability.

DESIGN

Practice audit.

SETTING

Private practice of senior author.

SUBJECTS

Prospective series of 23 consecutive patients.

METHODS

Outcomes were measured using a numerical rating scale for neck pain, and the Neck Disability Index for disability. Success rates were calculated for various degrees of improvement of neck pain at long-term follow-up (8-40 months), and for achieving various combinations of improvement of both neck pain and disability.

RESULTS

Complete relief of pain was achieved in 40% of patients, with a further 40% achieving at least 50% relief. At long-term follow-up, 30% of patients had no neck pain and no disability, and a further 25% had only minimal pain, minimal disability, or both.

CONCLUSIONS

The present study did not corroborate earlier studies that claimed outstanding outcomes for arthrodesis of the LAAJ, but its outcomes are consonant with more recent studies that provided transparent outcome data. These studies provide Pain Physicians with empirical data on success rates and outcomes, upon which they can base their consideration of referral for arthrodesis.

Is neck pain treatable with surgery?

INTRODUCTION

Neck pain is one of the most common complaints in clinical practice and can be caused by a wide variety of conditions. While cervical spine surgery is a well-accepted option for radicular pain and myelopathy, surgery for isolated neck pain is controversial. The identification of the source of pain is challenging and subtle, and misdiagnosis can lead to inappropriate treatment. MATERIALS AND METHODS AND RESULTS: We conducted a thorough literature review to discuss and compare different causes of neck pain. We then supplemented the literature with our senior author's expert analysis of treating cervical spine pathology.

CONCLUSIONS

This study provides an in-depth discussion of neck pain and its various presentations, as well as providing insight into treatment strategies and diagnostic pearls that may prevent mistreatment of cervical spine pathology.

The imaging of cervical spondylotic myeloradiculopathy

This review provides a detailed description of the imaging features of cervical spondylotic myelopathy and radiculopathy, with a focus on MRI. Where relevant, we will outline grading systems of vertebral central canal and foraminal stenosis. Whilst post-operative appearances of the cervical spine are outside the scope of this paper, we will touch on imaging features recognised as predictors of clinical outcome and neurological recovery. This paper will serve as a reference for both radiologists and clinicians involved in the care of patients with cervical spondylotic myeloradiculopathy.

Factors associated with the increased risk of atlantoaxial osteoarthritis: a retrospective study

Purpose Atlantodens osteoarthritis and atlantoaxial osteoarthritis cause neck pain and suboccipital headaches. Currently, knowledge on the risk factors for atlantoaxial osteoarthritis is lacking. This study aimed to investigate the factors related to the increased risk of atlantoaxial osteoarthritis. Methods We analyzed computed tomography (CT) images of the upper cervical spine of 1266 adult trauma patients for whom upper cervical spine CT was performed at our hospital between 2014 and 2019. The degree of atlantoaxial osteoarthritis was quantified as none-to-mild (not having osteoarthritis) or moderate-to-severe (having osteoarthritis). Risk factors associated with atlantoaxial osteoarthritis were identified using univariate and multivariable logistic regression analyses. Results The study group included 69.4% men, and the overall average age of the study population was 54.9 ± 20.4 years. The following factors were independently and significantly associated with atlantoaxial osteoarthritis in the multivariable logistic regression analysis: age in the sixth decade or older (odds ratio [OR], 20.5; 95% confidence interval [CI], 6.2‒67.2, p < 0.001), having calcific synovitis (OR, 4.9; 95% CI, 2.4‒9.9, p < 0.001), women sex (OR, 3.3; 95% CI, 1.9‒5.7, p = 0.002), and not having atlantodens osteoarthritis (OR, 2.1; 95% CI, 1.2‒3.8, p = 0.014). Conclusion In the multivariable logistic regression analysis, age in the sixth decade or older, calcification of the transverse ligament, being women, and not having atlantodens osteoarthritis were found to be significantly associated with atlantoaxial osteoarthritis. Delayed diagnosis and treatment can be avoided by focusing on these risk factors.

Research Progress of Atlantoaxial Osteoarthritis: A Narrative Literature Review

OBJECTIVE

The purpose of this review was to consolidate the current literature related to atlantoaxial osteoarthritis (AAOA) and improve the systematic understanding of this clinical syndrome among spine surgeons.

METHODS

Articles reviewed were searched in PubMed, Ovid MEDLINE, and EMBASE using search terms: [("C1-C2" OR "C1-2" OR "atlantoaxial" OR "atlanto-axial" OR "C2" OR "C1" OR "atlas" OR "axis") AND ("osteoarthritis")]. All articles of any study design discussing on AAOA were considered for inclusion. Two independent authors read article titles, abstracts and the included appropriate articles. The relevant articles were studied in full text.

RESULTS

A total of 54 literatures were reviewed and consolidated in this narrative review. These articles are roughly divided into the following five subcategories: (1) epidemiology and etiology, (2) clinical presentation, (3) radiographic findings, (4) conservative treatment and (5) surgical indications and treatment options.

CONCLUSION

AAOA was a clinically common but often overlooked syndrome characterized by persistent occipitocervical pain. The most common cause of AAOA was joint degeneration, which was closely related to age and occupation. Initial treatment for AAOA was conservative. Atlantoaxial fusion was an option for patients with severe pain who unresponsive to conservative management.

Fluoroscopy-Assisted C1-C2 Posterior Fixation for Atlantoaxial Instability: A Single-Center Case Series of 78 Patients

Background and Objectives: Posterior C1-C2 fixation, with trans-articular screws (TAS) or screw-rod-construct (SRC), is the main surgical technique for atlantoaxial instability, and can be performed with a fluoroscopy-assisted free-handed technique or 3D navigation. This study aimed to evaluate complications, radiological and functional outcome in patients treated with a fluoroscopy-assisted technique. Materials and Methods: A single-center consecutive cohort study was conducted of all adult patients who underwent posterior C1-C2 fixation, using TAS or CRS, between 2005-2019. Results: Seventy-eight patients were included, with a median follow-up time of 6.8 years. Trauma was the most common injury mechanism (64%), and cervicalgia the predominant preoperative symptom (88%). TAS was used in 33%, and SRC in 67% of cases. Surgery was associated with a significant reduction in cervicalgia (from 88% to 26%, p < 0.001). The most common complications were vertebral artery injury (n = 2, 2.6%), and screw malposition (n = 5, 6.7%, of which 2 were TAS and 3 were SRC). No patients deteriorated in their functional status following surgery. Conclusions: Fluoroscopy-assisted C1-C2 fixation with TAS or SRC is a safe and effective treatment for atlantoaxial instability, with a low complication rate, few surgical revisions, and pain relief in the majority of the cases.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

BACKGROUND

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

METHODS

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4-5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

RESULTS

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

CONCLUSIONS

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Consensus practice guidelines on interventions for cervical spine (facet) joint pain from a multispecialty international working group

Background

The past two decades have witnessed a surge in the use of cervical spine joint procedures including joint injections, nerve blocks and radiofrequency ablation to treat chronic neck pain, yet many aspects of the procedures remain controversial.

Methods

In August 2020, the American Society of Regional Anesthesia and Pain Medicine and the American Academy of Pain Medicine approved and charged the Cervical Joint Working Group to develop neck pain guidelines. Eighteen stakeholder societies were identified, and formal request-for-participation and member nomination letters were sent to those organizations. Participating entities selected panel members and an ad hoc steering committee selected preliminary questions, which were then revised by the full committee. Each question was assigned to a module composed of 4–5 members, who worked with the Subcommittee Lead and the Committee Chairs on preliminary versions, which were sent to the full committee after revisions. We used a modified Delphi method whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chairs, who incorporated the comments and sent out revised versions until consensus was reached. Before commencing, it was agreed that a recommendation would be noted with >50% agreement among committee members, but a consensus recommendation would require ≥75% agreement.

Results

Twenty questions were selected, with 100% consensus achieved in committee on 17 topics. Among participating organizations, 14 of 15 that voted approved or supported the guidelines en bloc, with 14 questions being approved with no dissensions or abstentions. Specific questions addressed included the value of clinical presentation and imaging in selecting patients for procedures, whether conservative treatment should be used before injections, whether imaging is necessary for blocks, diagnostic and prognostic value of medial branch blocks and intra-articular joint injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for designating a block as positive, how many blocks should be performed before radiofrequency ablation, the orientation of electrodes, whether larger lesions translate into higher success rates, whether stimulation should be used before radiofrequency ablation, how best to mitigate complication risks, if different standards should be applied to clinical practice and trials, and the indications for repeating radiofrequency ablation.

Conclusions

Cervical medial branch radiofrequency ablation may provide benefit to well-selected individuals, with medial branch blocks being more predictive than intra-articular injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of false-negatives (ie, lower overall success rate). Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

A novel classification and algorithmic-based management of craniovertebral junction osteoarthrosis

Introduction:

The objective of this study is to propose a novel classification and algorithmic-based management plan for craniovertebral junction osteoarthrosis (CVJOA).

Materials and Methods:

A retrospective study was done based on prospective database of radiological studies and clinical history. Twenty symptomatic patients (12 females and 8 males) with a mean age of 54.8 years were identified with CVJOA. These patients underwent either nonsurgical treatment only or surgical intervention and had follow-up of at least 14 months. Classification of CVJOA is based on coronal deformity, rigidity, stability, and two modifiers. The main surgical procedures done in the surgical arm of these patients included C1–C2 fusion, C1–C2 facet distraction and fusion, and unilateral subaxial facet distraction, and posterior column osteotomy.

Results:

All the twenty patients included in this study complained of either sub-occipital or upper neck pain and had radiological evidence of CVJOA. Seven patients improved with nonsurgical management and 13 underwent surgical intervention. Surgical recommendations for each type of CVJOA have been described with case examples, and algorithm for the management of CVJOA has been developed based on this study. Interobserver agreement on CVJOA classification was measured using kappa value statistics which showed moderate strength of agreement (0.467).

Conclusion:

This study describes a novel classification and management of CVJOA based on algorithm and current surgical recommendations for each type of CVJOA.

Improvements in Neck Pain and Disability Following C1-C2 Posterior Cervical Instrumentation and Fusion for Atlanto-Axial Osteoarthritis

OBJECTIVE

Symptomatic Atlanto-axial (C1-2) osteoarthritis (AAOA) is a common phenomenon in elderly patients; however, there is a paucity of data on the effectiveness of posterior atlanto-axial fusion (PAAF) for this condition. To this end, here we assess changes in patient-reported outcomes and neck-related disability in adult patients undergoing PAAF for symptomatic C1-2 AAOA.

METHODS

In this retrospective study, the clinical records of consecutive patients with symptomatic AAOA who underwent PAAF between 2004 and 2017 were reviewed. Patient demographics, comorbidities, intraoperative and postoperative variables, and complication rates were collected. Neck Disability Index (NDI) scores were recorded at baseline and 6 weeks, 6 months, 1 year, and 2 years postoperatively.

RESULTS

Forty-two patients (average age, 72.04 ± 8.56 years; 26.19% males) met the study's inclusion criteria. In this cohort, 19.04% had previous subaxial cervical spine surgery, 35.71% had a history of smoking (all had stopped smoking before surgery), and 11.90% had type II diabetes. At baseline, the majority of patients had a normal neurologic exam. The average preoperative NDI score was 26.88 ± 24.85, which improved to 10.59 ± 14.88 at the 1-year follow-up and 13.20 ± 14.96 at the 2-year follow-up (P = 0.004). At baseline, 18% of the patients reported severe disability based on NDI score; this percentage decreased to 2% at 1 year and 0 at 2 years (P = 0.01). Importantly, a high percentage (11.90%) of patients had undergone previous subaxial cervical fusion for their pain due to a mistaken diagnosis for this condition, without symptom relief.

CONCLUSIONS

In appropriately selected patients, PAAF may decrease neck pain and improve functional disability in patients with AAOA. Future prospective longitudinal studies are needed to corroborate these findings.

Suboccipital neuralgia after C1 pedicle screw insertion: do we neglect atlantooccipital joint violation? - Case report and literature review

Background

Occipital neuralgia is one of the postoperative complications of C1 lateral mass screw insertion, which was deemed to be related with the C2 nerve root dysfunction.

Case presentation

A 52-year-old female patient presented with gradually progressive numbness and weakness in her extremities for 6 months. X-ray and computed tomography (CT) scan revealed obvious anterior atlantoaxial dislocation (ADD), which was reducible on extensive view. Atlantoaxial pedicle screw fixation and bone graft was performed. Immediately after the operation, the neurological symptom significantly improved. The patient complained of restricted cervical rotation and suboccipital neuralgia which was exacerbated by rotation with an intensity of 7 on a visual analog scale (VAS) ranging from 0 to 10 at postoperative day 5. While a satisfactory reduction was detected in the postoperative CT, violation of the left atlantooccipital joint was observed in the left C1 screw. Nimesulide (daily dosage of 0.2 g) and bracing were recommended immediately. At the 2 month follow-up, both the neurological improvement and reduction were maintained. The VAS of suboccipital neuralgia is 3 and decreased to 1 at 6 months postoperative. Bony fusion of the left atlantooccipital joint was confirmed by CT scan at 6 months postoperative. The patient complained that the suboccipital neuralgia was tolerable without the assistance of braces or medications for pain. At the 18 month follow-up, only stiffness of head flexion and rotation was observed without suboccipital neuralgia.

Conclusion

Suboccipital neuralgia after atlantooccipital joint violation of C1 pedicle screw placement most likely results from C1 nerve root irritation. As the corresponding dermatome differs from the distributing region and aggravated factor of C2 nerve root dysfunction, neuralgia due to C1 irritation was only localized at suboccipital region and exacerbated by rotation.

Clinical and radiological outcomes of image guided posterior C1-C2 fixation for atlantoaxial osteoarthritis (AAOA)

Background

Atlantoaxial (C1-C2) osteoarthritis (AAOA) causes severe suboccipital pain exacerbated by lateral rotation. The pain is usually progressive and resistant to conservative therapy. Posterior fusion surgery is performed to stabilise the C1-C2 segment. This is the first Australian study reporting the outcome of posterior atlantoaxial fixation including hybrid fixations performed for AAOA.

Methods

All patients who underwent posterior atlantoaxial fixation surgery for AAOA from 2005 to 2015 at our institutions were enrolled (N=23). Patient demographics and surgical technique were recorded. These techniques included transarticular screw (TAS) fixation using image guidance with iliac crest bone graft and supplemental posterior Sonntag wiring, or C1-C2 lateral mass fixation (Harms technique). Some patients required a combination of fixation due to anatomical variation. Primary outcome measures including patient satisfaction, pain, disability scores and range of motion were recorded for all patients pre- and post-operatively. Post-operative assessment was supplemented with CT and X-ray imaging.

Results

Twenty-three patients (19 women, 4 males, mean age 71.8±6.3 years) underwent surgical fixation. Eight underwent TAS fixation, 8 had Harms fixation, and 7 had a hybrid fixation. All patients reported statistically significant improvement in pain scores [Visual Analogue Scale (VAS) 9.4 pre-op compared to 2.9 post-op, P<0.005]. Disability scores [Neck Disability Index (NDI)] were statistically significantly reduced from 72.2±12.9 pre-operatively to 18.9±11.9 post-operatively, P<0.005. Mean follow-up was 55.3±36.1 months. Results did not vary according to the construct type. Ninety-five point five percent of patients showed radiographic evidence of fusion. Ninety-one percent of patients said they would undergo the surgery again.

Conclusions

Posterior atlantoaxial fixation with TAS and Harms constructs are highly effective for the surgical treatment of intractable neck pain secondary to atlantoaxial lateral mass osteoarthritis (AAOA). Surgery offers a high rate of symptom relief. If anatomical variability exists, both transarticular and pedicle screw fixation could be safely used in the same patient.

Lateral Atlantoaxial Osteoarthritis: A Narrative Literature Review

Lateral atlantoaxial osteoarthritis (AAOA), or C1-C2 lateral mass arthritis (LMA), is an unfamiliar degenerative cervical disease with a clinical presentation that markedly differs from subaxial spondylosis. The prevalence of LMA in the nonsurgical outpatient setting is 4%. Risk factors include age and occupation. The typical patient is between 50 and 90 years old, presents with upper cervical or occipital pain, has limited rotation, and has pain provocation during passive rotation to the affected side. Pain stems from degeneration of the lateral C1-C2 articulation and may be referred or radicular, through the greater occipital nerve. Although there is no consensus on diagnostic work-up, the disease is classically seen on the open-mouth odontoid radiograph. Computerized tomography, magnetic resonance imaging, bone scan, and diagnostic injections are also useful. Initial treatment is conservative, and upwards of two-thirds of LMA patients obtain lasting relief with noninvasive measures and injections. In patients with severe, recalcitrant pain, limited C1-C2 fusion offers satisfactory and reliable relief. The goals of this review article are to provide a synthesis of the literature on LMA, to offer a treatment approach to LMA, and to identify problems with the current state of knowledge on LMA.

Outcomes Following Arthrodesis for Atlanto-Axial Osteoarthritis

STUDY DESIGN

Retrospective analysis.

OBJECTIVE

We set out to evaluate the radiographic and patient-reported outcomes following C1-C2 arthrodesis for atlantoaxial osteoarthritis (AAOA) using modern instrumentation and techniques.

SUMMARY OF BACKGROUND DATA

Few studies have evaluated outcomes following C1-C2 arthrodesis for AAOA using modern surgical fixation techniques.

METHODS

Retrospective analysis of all patients following C1-C2 arthrodesis with recalcitrant AAOA from a single center, single surgeon from 2002 to 2012. Preoperative, immediate and final follow-up postoperative radiographic images were evaluated. Patient-reported outcomes scores were assessed preoperative, 1-year, and final postoperative follow-up.

RESULTS

We found a total of 14 patients (13 female, 1 male) with average follow-up of 2.96 ± 2.26 years and mean age at surgery of 71.8 ± 9.3 years old. The most common construct was posterior C1-C2 bilateral screw-rod construct (SRC) (n = 9), and there were 3 patients with transarticular screw (TAS) constructs, and 2 patients with hybrid fixation (unilateral SRC and contralateral TAS). Mean change from baseline to final follow-up for Numeric Pain Rating Scale (NRS) was -4.7 ± 2.1, and Neck Disability Index (NDI) was -21.0 ± 13.6, with 11 (78.6%) patients demonstrated a substantial clinical benefit (change in NDI ≥ 10). There were no differences from baseline to all follow-up time points for SF-12 Physical and Mental Component Scores. All patients had evidence of solid C1-C2 arthrodesis and stable fixation at final follow-up, with no significant change in subaxial sagittal alignment. There were no perioperative or postoperative complications.

CONCLUSION

We report one of the largest series evaluating patient-reported outcomes in patients following arthrodesis for AAOA using modern C1-C2 fixation techniques. Our study found C1-C2 arthrodesis for AAOA to be safe and effective, with a significant improvement in patient-reported pain and neck disability and most patients reporting substantial clinical benefit.

LEVEL OF EVIDENCE

4.

Joint arthropathy at the cranio-vertebral junction. Scintigraphic patterns on bone SPECT/CT

Osteoarthritic degeneration at the cranio-vertebral junction (CVJ) is an underrecognized source of suboccipital and neck pain, limited range of motion and cervicogenic headaches. Correlation of radiographic findings with clinical symptoms is often difficult. Limited evidence currently exists to support the use of bone single-photon emission computed tomography/computed tomography (SPECT/CT) in this subgroup of patients. The aim of this study was to describe the scintigraphic patterns of joint arthropathy at the CVJ on bone SPECT/CT in patients with suboccipital/neck pain and cervicogenic headache. Patients with more than 3 months of suboccipital/neck pain/cervicogenic headache and abnormal SPECT/CT findings at the CVJ were included. Patients with known/suspected malignancy, trauma, infectious processes and previous surgery at the CVJ were excluded. Neck disability index (NDI), visual analogue scale (VAS) and treatment were recorded for each patient. Patterns of osteoblastic activity at the CVJ on bone SPECT/CT were described and correlated with arthritic changes on conventional scans. Eighteen patients were included (10 females, mean age 68). Mean NDI score was 22. Mean VAS was 7.5. On bone SPECT/CT, it was found that 13 patients had high osteoblastic activity unilaterally at the atlanto-axial joint (AAJ); two patients at the atlanto-dental joint (ADJ), one at the occipito-atlantal joint (OAJ), one at both OAJ and ADJ and one at the level of C2 pars/pedicle unilaterally. Metabolic activity on SPECT/CT was associated with severe degenerative changes on CT scans. The ability of hybrid bone SPECT/CT to precisely localize osteoblastic activity at the CVJ may provide significant improvement in the diagnosis and treatment of patients with suboccipital/neck pain and joint arthropathy at the CVJ. Further clinical studies are needed to establish the real clinical impact of bone SPECT/CT in the treatment of patients with suboccipital neck pain.

Occipital neuralgia secondary to unilateral atlantoaxial osteoarthritis: Case report and review of the literature

Background:

Atlantoaxial osteoarthritis (AAOA), either in isolation or in the context of generalized peripheral or spinal arthritis, presents most commonly with neck pain and limitation of cervical rotational range of motion. Occipital neuralgia (ON) is only rarely attributed to AAOA, as fewer than 30 cases are described in the literature.

Case Description:

A 64-year-old female presented with progressive incapacitating cervicalgia and occipital headaches, refractory to medications, and local anesthetic blocks. Computed tomography and magnetic resonance imaging studies documented advanced unilateral atlantoaxial arthrosis with osteophytic compression that dorsally displaced the associated C2 nerve root. Surgical decompression and atlantoaxial fusion achieved rapid and complete relief of neuralgia. Ultimately, postoperative spinal imaging revealed osseous union.

Conclusions:

Atlantoaxial arthrosis must be considered in the differential diagnosis of ON. Surgical treatment is effective for managing refractory cases. Intraoperative neuronavigation is also a useful adjunct to guide instrumentation and the intraoperative extent of bony decompression.

Posterior atlantoaxial 'facetal' instability associated with cervical spondylotic disease

Aim:

The association of single or multiple level cervical spondylotic disease with atlantoaxial instability is assessed. The implications of identifying and treating atlantoaxial instability in such an association are highlighted.

Materials and Methods:

The analysis is based on an experience with 11 patients treated during the period June 2013-June 2014. All patients had single or multilevel cervical spondylotic disease. The spinal canal compromise and evidence of cord compression was evident on imaging in the cervical subaxial spine and was related to disc bulges and osteophytic bars. There was no or relatively insignificant compression of the cervicomedullary cord by the odontoid process. There was no evidence of odontoid process-related instability on dynamic imaging. Apart from presence of features of cervical spondylosis, investigations and surgical exploration and direct manual handling of the facets revealed evidence of Type B (posterior) atlantoaxial ‘facetal’ instability in all patients. Our 5-point clinical grading system and Japanese Orthopaedic Association (JOA) scores were used to monitor the patients both before and after surgery and at follow-up. Surgery involved both at lantoaxial and subaxial cervical fixation. During the average period of follow-up of 9 months (5-17 months), all patients showed remarkable and gratifying neurological recovery.

Conclusion:

We conclude that atlantoaxial facetal instability can be ‘frequently’ associated with cervical spondylosis and needs surgical stabilization. Our surgical outcome analysis suggests that missing or ignoring the presence of atlantoaxial facetal instability can be an important cause of suboptimal result or failure of surgery for cervical spondylotic myelopathy.