Occipitocervical fusion has potential to improve sleep apnea in patients with rheumatoid arthritis and upper cervical lesions

Radiographic Prediction of the Occipito-C2 Angle Variation with Changes in Distance between the Mandible and Cervical Vertebrae: A Preliminary Study

The Occipito (O) -C2 angle reflects the correct craniocervical spine alignment; however, the poor image quality of standard intraoperative fluoroscopy at times lead to inaccurate measurements. Herein, we preliminarily investigated the relationship between the O-C2 angle and the Gonion-C2 distance, which is based on the positioning of the mandible and the cervical spine. We enrolled patients who underwent cervical spine radiography in neutral, flexion, and extension positions from January 2020 to October 2020. The difference by posture changes for each parameter was defined as the Δ value, and the Spearman's rank correlation coefficient was determined. Furthermore, we determined the cutoff value of the ΔGonion-C2 distance to predict a decrease of > 10° in the ΔO-C2 angle, which is reported to be related to dysphagia and dyspnea. Seventy-four patients were included. Spearman's rank correlations for the neutral, flexion, and extension positions were 0.630 (P < 0.001), 0.471 (P < 0.001), and 0.625 (P < 0.001), respectively, while the cutoff values of the ΔGonion-C2 distance for predicting > 10° in the ΔO-C2 angle were 9.3 mm for the neutral flexion change (sensitivity: 0.435, specificity: 0.882) and 8.3 mm for the extension-neutral change (sensitivity: 0.712, specificity: 0.909). The O-C2 angle and Gonion-C2 distances correlated; however, this correlation was weaker in the flexed position. Nevertheless, the ΔGonion-C2 distance can be used as a warning sign for postoperative complications after posterior occipital bone fusion surgery, because a decrease of > 10° in the ΔO-C2 angle can be predicted with high specificity.

Prevalence of obstructive sleep apnea among patients with rheumatoid arthritis and its association with age and body mass index: A systematic review and meta-analysis

AIM

The study aims to recognize the prevalence and possible risk factors of obstructive sleep apnea among individuals with rheumatoid arthritis (RA).

METHODS

We searched PubMed, Scopus, EMBASE, and Google scholar for potential studies published before the October 30, 2020. The study characteristics, obstructive sleep apnea (OSA) events, and various types of rheumatic diseases were extracted, and the meta-analysis method was used to pool the estimates.

RESULTS

We identified eight studies with 37 285 patients for this meta-analysis. The overall pooled prevalence of OSA was 29.8% (95% confidence interval [CI] 15.2-46.7; I²  = 99.6%) in the patients with RA. Age was higher in RA patients with OSA but this was not significant. Body mass index (BMI) was significantly associated with OSA in the RA population (standardized mean difference 1.08; P = 0.044). Assessment based on the Berlin Questionnaire^© for Sleep Apnea resulted in a more precise estimate of OSA prevalence with reduced heterogeneity (prevalence 45.3%; 95% CI 37.4-53.3; I²  = 58.8%).

CONCLUSION

Prevalence of OSA among the RA cohort was 29.8% with significant heterogeneity. However, the prevalence was 45.3% when studies were restricted to the OSA diagnosis based on the Berlin questionnaire with very low heterogeneity. Higher BMI is the principal risk factor of OSA development in RA. Hence, controlling BMI could be a preventive strategy for OSA among RA patients.

A radiologic parameter that could be applied in the development of sleep apnea in rheumatoid arthritis patients undergoing occipitocervical fusion

BACKGROUND

The prevalence of sleep apnea in rheumatoid arthritis (RA) patients with occipitocervical lesions was 79%. Occipitocervical fusion (OCF) could incur sleep apnea or worsen this condition. Recent studies reported that this complication is caused by stenosis of the oropharyngeal airway accompanying a decrease in the occipitoaxial angle (O-C2a). However, there are several limitations to the application of the O-C2a, which decreases its effectiveness. Therefore, we aimed to evaluate the association between a new radiologic parameter, the CVT/NSL angle (CVT: craniocervical inclination in the second and fourth vertebrae; NSL: Nasion-Sella line), and sleep apnea in RA patients accepting OCF.

METHODS

A total of 35 patients who underwent OCF due to upper cervical lesions secondary to RA and had sleep apnea before surgery were analyzed. Those who have a postoperative apnea-hypopnea index (AHI) < 15 and a ΔAHI ≥50% were considered "responders"; patients were otherwise considered "non-responders." They were analyzed whether pre- and postoperative radiologic parameters and their differences in plain lateral radiographs were correlated to the parameter related to sleep apnea.

RESULTS

The included patients have a mean AHI of 21.9 (range, 10 to 52) before surgery. The mean postoperative CVT/NSLa, ΔCVT/NSLa, andΔO-C2a in complete responders were significantly greater compared with non-responders (p < 0.05). Both the changes in the CVT/NSLa and O-C2a were linearly correlated within patients. However, the R² value for the CVT/NSLa was greater compared with the O-C2a (0.403 vs. 0.203).

CONCLUSIONS

The usefulness of the new craniovertebral angle, CVT/NSLa, as an intraoperative indicator during OCF, is more valuable in comparison with the conventional method of measuring the O-C2a. Measuring the craniovertebral angle is extremely important in the planning of surgical treatment for the development of sleep apnea in rheumatoid arthritis patients undergoing occipitocervical fusion.

[Predictive abilities of O-C2 angle, O-EA angle, and Oc-Ax angle for the development of dysphagia in patients after occipitocervical fusion]

Objective

To compare the predictive abilities of O-C2 angle (O-C2a), O-EA angle (O-EAa), and Oc-Ax angle (Oc-Axa) for development of dysphagia in patients after occipitocervical fusion (OCF).

Methods

Between April 2010 and May 2019, 114 patients who underwent OCF and met the selection criteria were selected as the research objects. Among them, 54 were males and 60 were females; they were 14-76 years old, with an average of 50.6 years old. The follow-up time was 13-122 months (median, 60.5 months). The O-C2a, O-EAa, Oc-Axa, and the narrowest oropharyngeal airway space (nPAS) were measured by the lateral X-ray films before operation and at last follow-up, and the differences before and after operation (dO-C2a, dO-EAa, dOc-Axa, and dnPAS) were calculated. Patients were divided into two groups according to whether they had developed postoperative dysphagia. The general data including age, gender, fixed segment, proportion of patients with rheumatoid arthritis (RA), atlantoaxial subluxation (AS), and combined with anterior release surgery (ARS), and imaging indicators were compared between the two groups. The correlations between dO-C2a, dO-EAa, and dOc-Axa and dnPAS in 114 patients were analyzed to further compare the predictive value of three imaging indicators for occurrence of dysphagia after OCF.

Results

Dysphagia occurred after OCF in 31 cases with the incidence of 27.2%. There was significant difference in gender between the dysphagia group and the non-dysphagia group ( χ ²=7.940, P=0.005). There was no significant difference between the two groups in age, fixed segment, the proportion of patients with RA, the proportion of patients with AS, and the proportion of patients combined with ARS ( P>0.05). There was no significant difference in O-C2a and Oc-Axa of 114 patients before operation and at last follow-up ( P>0.05). The differences in O-EAa and nPAS were significant ( P<0.05). There was no significant difference in preoperative O-EAa, Oc-Axa, and nPAS between the dysphagia group and the non-dysphagia group ( P>0.05); the difference in the O-C2a was significant ( t=2.470, P=0.016). At last follow-up, the differences in the above imaging indicators were significant ( P<0.05). There were significant differences in the dO-C2a, dO-EAa, dOc-Axa, and dnPAS between the two groups ( P<0.05). Correlation analysis showed that the dO-C2a, dO-EAa, dOc-Axa were all positively correlated with dnPAS ( P<0.05). The dO-C2a≤-5°, postoperative O-EAa≤100°, postoperative Oc-Axa≤65° were all related to postoperative dysphagia ( P<0.05), and the highest risk factor suffering postoperative dysphagia was dO-C2a ≤-5° with a significant OR of 14.4.

Conclusion

The dO-C2a, postoperative O-EAa, and postoperative Oc-Axa can be used as the predictive indexes of dysphagia after OCF, among which dO-C2a has the highest predictive value.

Surgical Treatment for Central Sleep Apnea due to Occipitocervical Compression Myelopathy in a Patient with Klippel-Feil Syndrome

BACKGROUND

Central sleep apnea (CSA) due to occipitocervical compression myelopathy is an extremely rare condition. Here we report a case of surgical treatment for CSA due to occipitocervical compression myelopathy in a patient with Klippel-Feil syndrome.

CASE DESCRIPTION

A 60-year-old man had become aware of a gradually progressive clumsiness and gait disturbance without any cause of injury 5 years before. He had complicated respiratory discomfort during sleep for the previous month and visited our hospital. Neurologic examination revealed severe myelopathy. Polysomnography showed CSA and Cheyne-Stokes respiration. Imaging findings showed C2-3 vertebral fusion and severe spinal cord compression caused by hypoplasia of the C1 posterior arch complicated by an anomaly of the vertebral artery. We diagnosed the patient with CSA due to occipitocervical compression myelopathy complicated by Klippel-Feil syndrome. After a simulation using a full-scale 3-dimensional model, resection of the C1 posterior arch and C4-5 laminoplasty was performed. After surgery, both clumsiness and gait disturbance gradually improved. Polysomnography 1 month after surgery showed that the CSA and the Cheyne-Stokes respiration disappeared.

CONCLUSIONS

Although a recent report has indicated the cause of sleep apnea in patients with rheumatoid arthritis and occipitocervical disorders as obstructive sleep apnea, a significant improvement of CSA was observed with decompression surgery in this case. Appropriate surgical planning resulted in a favorable outcome.

Effects of surgically assisted rapid maxillary expansion on the modification of the pharynx and hard palate and on obstructive sleep apnea, and their correlations

PURPOSE

To investigate the changes induced by surgically assisted rapid maxillary expansion (SARME) on palate and pharynx morphology as well as the correlation of these changes with the improvement of obstructive sleep apnea (OSA).

MATERIALS AND METHODS

The study was conducted in 16 patients, seven women and nine men, aged on average 40.23 ± 10.23 years, all of them with OSA confirmed by polysomnography (PSG) and with posterior crossbite. All participants underwent computed tomography (CT) and PSG before and after SARME. The CT scans were used to determine the dimensions of the palate and pharynx before and after surgery. Data were analyzed statistically by the paired t-test, Wilcoxon test and Pearson correlation, with the level of significance set at P < 0.05.

RESULTS

A 56.24% reduction in apnea and hypopnea index was detected (from 33.23 ± 39.54 to 14.54 ± 19.48: P = 0.001). The total airway area increased on average by 23.99% (P = 0.016), although in a more expressive manner in its lower half (28.63%, P = 0.008). A 24% transverse bone increase was observed in the palate in the region of the first premolars and an 18% increase in the region of the first molars (from 2.42 ± 0.31 to 2.99 ± 0.26. P < 0.001, and from 3.11 ± 0.32 to 3.70 ± 0.41, P < 0.001, respectively), and a mean 15% reduction of its depth (from 1.07 ± 0.33 to 0.89 ± 0.18, P = 0.014). A moderate correlation was detected between palate depth and width and OSA severity, as well as a correlation of the reduction of palate depth and its transverse increase with the improvement of OSA, especially among patients with severe OSA.

CONCLUSION

It appears that narrowing of the palate, especially in the premolar region, and its greater depth may be related to the severity of OSA. SARME promotes transverse maxillary widening and lowering of palate depth, thus reducing OSA among adults and expanding the airway, especially in its lower half.

Cervical Spine Hyperextension and Altered Posturo-Respiratory Coupling in Patients With Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) is associated with postural dysfunction characterized by abnormal spinal curvature and disturbance of balance and walking, whose pathophysiology is poorly understood. We hypothesized that it may be the result of a pathological interaction between postural and ventilatory functions. Twelve patients with OSAS (4 women, age 53 years [51–63] (median [quartiles]), apnea hypopnea index 31/h [24–41]) were compared with 12 healthy matched controls. Low dose biplanar X-rays (EOS® system) were acquired and personalized three-dimensional models of the spine and pelvis were reconstructed. We also estimated posturo-respiratory coupling by measurement of respiratory emergence, obtaining synchronized center of pressure data from a stabilometric platform and ventilation data recorded by an optico-electronic system of movement analysis. Compared with controls, OSAS patients, had cervical hyperextension with anterior projection of the head (angle OD-C7 12° [8; 14] vs. 5° [4; 8]; p = 0.002), and thoracic hyperkyphosis (angle T1–T12 65° [51; 71] vs. 49° [42; 59]; p = 0.039). Along the mediolateral axis: (1) center of pressure displacement was greater in OSAS patients, whose balance was poorer (19.2 mm [14.2; 31.5] vs. 8.5 [1.4; 17.8]; p = 0.008); (2) respiratory emergence was greater in OSAS patients, who showed increased postural disturbance of respiratory origin (19.2% [9.9; 24.0] vs. 8.1% [6.4; 10.4]; p = 0.028). These results are evidence for the centrally-mediated and primarily respiratory origin of the postural dysfunction in OSAS. It is characterized by an hyperextension of the cervical spine with a compensatory hyperkyphosis, and an alteration in posturo-respiratory coupling, apparently secondary to upper airway instability.

Unstable os odontoideum contributing to cervical myelopathy and obstructive sleep apnea

Background:

Sleep apnea is characterized by repetitive cessation of breathing during sleep. It may be attributed to obstructive, central, or mixed pathologies close to the upper airway resulting in a decreased diameter of the oropharyngeal tract.

Case Description:

A 36-year-old male with progressive cervicomedullary myelopathy/quadriparesis exhibited obstructive sleep apnea (OSA) attributed to an anteriorly displaced os odontoideum (OO). Atlantoaxial screw-rod stabilization resulted in improvement of both neurological function and OSA.

Conclusion:

A symptomatic unstable OO may contribute to suboccipital pain, progressive quadriparesis, vertebrobasilar insufficiency, and OSA. Appropriate operative intervention utilizing atlantoaxial screw-rod stabilization may help to resolve these deficits.

Effects of transverse maxillomandibular distraction osteogenesis on obstructive sleep apnea syndrome and on the pharynx

PURPOSE

To assess the effects of transverse maxillomandibular distraction osteogenesis (TMDO) on the treatment of obstructive sleep apnea (OSA) and on the morphology of the pharynx.

METHODS

A clinical trial was conducted with seven patients with OSA and with transverse maxillomandibular deficiency, two women and five men aged on average 41.16 ± 10.9 years on the day of surgery. All participants were submitted to computed tomography (CT) and full-night polysomnography (PSG) before and approximately 9 months after surgery. A 95% confidence interval was defined.

RESULTS

The AHI and RDI of the participants were reduced by about 62% (from 27.65 ± 36.65 to 10.73 ± 11.78, p = 0.031 and from 41.21 ± 32.73 to 15.30 ± 13.87, p = 0.015, respectively). The airway showed a surprising mean reduction in volume of 10% (from 5.78 ± 2.53 to 4.71 ± 1.42, p = 0.437, for the upper pharynx; from 6.98 ± 2.23 to 6.23 ± 2.05, p = 0.437, for the lower pharynx; and from 12.76 ± 1.56 to 10.94 ± 2.42, p = 0.625, for the total pharynx). However, the site of the smallest area of the pharynx was considerably increased both in the anteroposterior and transverse direction and in its total area (from 0.88 ± 7.11 to 0.99 ± 0.39, p = 0.625; from 1.78 ± 0.81 to 2.05 ± 0.61, p = 0.812; and from 0.99 ± 0.74 to 1.40 ± 0.51, p = 0.180, respectively).

CONCLUSION

TMDO proved to be efficient in reducing or curing OSA, producing modifications of upper pharynx morphology with an increase of the smallest area of the pharynx.

A New Method of Measuring the Occipitocervical Angle That Could be Applied as an Intraoperative Indicator During Occipitocervical Fusion

STUDY DESIGN

A method for measuring occipitocervical angle.

OBJECTIVE

To develop a new method of measurement for assessing the occipitocervical angle using intraoperative fluoroscopic imaging, and to examine its reliability.

SUMMARY OF BACKGROUND DATA

To avoid postoperative complications following occipitocervical fusion, it is vital to obtain a suitable fusion angle between the occipital bone and the upper cervical spine.

MATERIALS AND METHODS

The subjects were 30 cases with occipito-atlanto-axial lesions and 30 healthy volunteers. Lateral plain radiographs of the cervical spine in neutral position were used to draw the McGregor line, the line between the external occipital protuberance and the most caudal point on the midline occipital curve (Oc line), the tangential line of the inferior endplate of the C2 vertebra (C2 line), and the posterior longitudinal line of the C2 vertebra (Ax line). The angles formed by these 4 lines and the horizontal line were measured. The O-C2 angle and the Oc-Ax angle, the new indicator, were measured by 3 doctors and reliability was evaluated.

RESULTS

In the disease group, mean intraobserver variances of the McGregor, Oc, C2, Ax, O-C2, and Oc-Ax angles were 0.7, 1.3, 1.5, 1.2, 1.6, and 1.9 degrees. Mean intraobserver intraclass correlation coefficients were 0.997, 0.994, 0.994, 0.997, 0.989, and 0.988, showing high intraobserver reliability for all angles. Mean interobserver intraclass correlation coefficients were 0.998, 0.996, 0.994, 0.997, 0.988, and 0.990, showing high interobserver reliability for all angles. The same reliability was obtained in the healthy group.

CONCLUSIONS

The Oc-Ax angle is as reliable an indicator as the conventional O-C2 angle, and could be used as a new intraoperative indicator for occipitocervical fusion. It may be particularly useful in cases where it is difficult to identify the McGregor line and/or the inferior endplate of the C2 vertebra.

LEVEL OF EVIDENCE

Level 3-diagnostic study.

Dysphagia After Occipitothoracic Fusion is Caused by Direct Compression of Oropharyngeal Space Due to Anterior Protrusion of Mid-cervical Spine

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To investigate the relationship among the craniocervical alignment, the oropharyngeal space, and the incidence of dysphagia after occipitothoracic fusion (OTF).

SUMMARY OF BACKGROUND DATA

Craniocervical malalignment after OTF is one of a trigger of dysphagia. However, there has been no logical explanation for the etiology yet.

METHODS

A total of 32 patients who underwent OTF (5 male, 27 female) were reviewed. Following 4 parameters on the lateral cervical radiogram, pharyngeal tilt angle (PTA); the angle between the McGregor's line and the line that links the center of C2 pedicle and the center of vertebral body at the apex of cervical sagittal curvature, diameter of oropharyngeal airway space (dPS), O-C2 angle, and C2-C7 angle were measured at follow-up and then the relationship of these parameters and their influence to the incidence of dysphagia were analyzed.

RESULTS

Six of 32 cases (18.8%) exhibited postoperative dysphagia. ROC curves showed that PTA and dPS had moderate accuracy for the predictor of the dysphagia after OTF with the area under the curve (AUC) of 0.76 and 0.86 respectively, whereas O-C2 angle had low accuracy with AUC of 0.69 and C2-C7 angle was almost useless for prediction of postoperative dysphagia with AUC of 0.51. A multiple linear regression analysis showed that only PTA was significantly correlated with dPS (β=0.822, P=0.014), whereas the O-C2 angle (β=0.101, P=0.779) and C2-C7 angle (β=0.352, P=0.157) had negligibly small influence on dPS.

CONCLUSIONS

Our results demonstrated strong relationships between PTA and the value of dPS, and the incidence of dysphagia. As PTA reflects anterior protrusion of mid-cervical spine, these results indicated that dysphagia after OTF is caused by narrowing of oropharyngeal space due to direct compression from anteirorly protruded mid-cervical spine.

Risk of Obstructive Sleep Apnea and Its Association with Cardiovascular and Noncardiac Vascular Risk in Patients with Rheumatoid Arthritis: A Population-based Study

OBJECTIVE

To define the incidence of obstructive sleep apnea (OSA) in patients with rheumatoid arthritis (RA) and determine whether OSA diagnosis predicts future cardiovascular disease (CVD) and noncardiac vascular events.

METHODS

Medical information pertaining to RA, OSA, CVD, and vascular diagnoses was extracted from a comprehensive medical record system for a geographically defined population of 813 patients previously diagnosed with RA and 813 age- and sex-matched comparator subjects.

RESULTS

The risk for OSA in persons with RA versus comparators was elevated, although not reaching statistical significance (HR 1.32, 95% CI 0.98-1.77; p = 0.07). Patients with RA were more likely to be diagnosed with OSA if they had traditional risk factors for OSA, including male sex, current smoking status, hypertension, diabetes, dyslipidemia, and increased body mass index. Features of RA disease associated with OSA included large joint swelling and joint surgery. Patients with RA with decreased renal function were also at higher risk of OSA. The increased risk of overall CVD among patients with RA who have OSA was similar to the increased CVD risk associated with OSA in the comparator cohort (interaction p = 0.86). OSA diagnosis was associated with an increased risk of both CVD (HR 1.9, 95% CI 1.08-3.27), and cerebrovascular disease (HR 2.4, 95% CI 1.14-5.26) in patients with RA.

CONCLUSION

Patients with RA may be at increased risk of OSA secondary to both traditional and RA-related risk factors. Diagnosis with OSA predicts future CVD in RA and may provide an opportunity for CVD intervention.

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.

Airway adverse events following posterior occipito-cervical spinal fusion

Management of the airway may be challenging in patients undergoing occipito-cervical spine fusions (OCF). Changes in the occipito-cervical angle (dOC2A) of fusion after surgery may result in acute airway obstruction, dyspnea and/or dysphagia. Objectives of the study were to review the airway management of patients during posterior OCF, determine the incidence, nature and risk factors for postoperative airway adverse events (AEs), and to determine the relationship between airway AEs and the change in dOC2A. In this retrospective cohort of 59 patients, following extubation in the operating room (OR), there were no complications in 43 (73%) patients (Group 1). Sixteen (27%) patients (Group 2) had airway complications; 4 requiring reintubation and 12 having delayed extubation. The number of vertebral levels fused (>6), presence of difficult intubation and duration of surgery (>5h) were significantly associated with AEs. There was no significant difference in the dOC2A between the groups (-1.070±5.527 versus -4.375±10.788, p=0.127). Airway management in patients undergoing OCF poses a challenge for the anesthesiology and surgical teams. The incidence of AEs was 27%. The decision to extubate immediately after surgery needs to be individualized. Factors such as difficult intubation, number of vertebral levels fused and duration of surgery have to be considered. A significant correlation between dOC2A and postoperative AEs could not be established. Risk factors for postoperative AEs are multifactorial and prospective evaluation of these factors is indicated.

Preliminary Evaluation of the Pathomechanisms of Dysphagia After Occipitospinal Fusion: Kinematic Analysis by Videofluoroscopic Swallowing Study

STUDY DESIGN

Kinematic analysis of swallowing function using videofluoroscopic swallowing study (VFSS).

OBJECTIVES

The aims of this study were to analyze swallowing process in the patients who underwent occipitospinal fusion (OSF) and elucidate the pathomechanism of dysphagia after OSF.

SUMMARY OF BACKGROUND DATA

Although several hypotheses about the pathomechanisms of dysphagia after OSF were suggested, there has been little tangible evidence to support these hypotheses since these hypotheses were based on the analysis of static radiogram or CT. Considering that swallowing is a compositive motion of oropharyngeal structures, the etiology of postoperative dysphagia should be investigated through kinematic approaches.

METHODS

Each four patients with or without postoperative dysphagia (group D and N, respectively) participated in this study. For VFSS, all patients were monitored to swallow 5-mL diluted barium solution by fluoroscopy, and then dynamic passing pattern of the barium solution was analyzed. Additionally, O-C2 angle (O-C2A) was measured for the assessment of craniocervical alignment.

RESULTS

O-C2A in group D was -7.5 degrees, which was relatively smaller than 10.3 degrees in group N (P = 0.07). In group D, all cases presented smooth medium passing without any obstruction at the upper cervical level regardless of O-C2A, whereas the obstruction to the passage of medium was detected at the apex of mid-lower cervical ocurvature, where the anterior protrusion of mid-lower cervical spine compressed directly the pharyngeal space. In group N, all cases showed smooth passing of medium through the whole process of swallowing.

CONCLUSION

This study presented that postoperative dysphagia did not occur at the upper cervical level even though there was smaller angle of O-C2A and demonstrated the narrowing of the oropharyngeal space towing to direct compression by the anterior protrusion of mid-lower cervical spine was the etiology of dysphagia after OSF. Therefore, surgeon should pay attention to the alignment of mid-cervical spine as well as craniocervical junction during OSF.

LEVEL OF EVIDENCE

4.

Risk of obstructive sleep apnoea in patients with rheumatoid arthritis: a nationwide population-based retrospective cohort study

OBJECTIVE

Sleep disorders are prevalent medical disorders in patients with rheumatoid arthritis (RA). However, whether patients with RA are at an increased risk of developing obstructive sleep apnoea (OSA) is unclear.

DESIGN

Using population-based retrospective cohort study to examine the risk of OSA in patients with RA.

SETTING

We used claims data of the National Health Insurance Research Database (NHIRD) of Taiwan.

PARTICIPANTS

We identified a RA cohort with 33 418 patients newly diagnosed in 2000-2010 and a randomly selected non-RA comparison cohort with 33 418 individuals frequency matched by sex, age and diagnosis year.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incident OSA was estimated by the end of 2011. The HRs of OSA were calculated using the Cox proportional hazards regression analysis.

RESULTS

The overall incidence rate of OSA was 75% greater in the RA cohort than in the non-RA cohort (3.04 vs 1.73/10 000 person-years, p<0.001), with an adjusted HR (aHR) of 1.75 (95% CI 1.18 to 2.60). Stratified analyses by sex, age group and comorbidity revealed that the incidence rates of OSA associated with RA were higher in all subgroups.

CONCLUSIONS

This population-based retrospective cohort study suggested that patients with RA should be monitored for the risk of developing OSA.

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.

Swallowing function after occipitocervical arthrodesis for cervical deformity in patients with rheumatoid arthritis

BACKGROUND

Some patients develop dysphagia after OC arthrodesis with RA. A previous report has indicated that establishing appropriate occipito-C2 is important for avoiding these side effects. However, a more recent report has demonstrated that the O-C2 angle did not have a significant effect on the incidence of postoperative dysphagia.

OBJECTIVE

To investigate the swallowing function of patients with rheumatoid arthritis (RA) before and after they underwent occipitocervical (OC) fusion.

METHODS

The study was performed in collaboration with the Departments of Orthopaedic, Otorhinolaryngology, and Rehabilitation. Seven consecutive patients (3 men and 4 women; mean age, 66.4 years) with RA-induced upper cervical deformity were enrolled from 2013 to 2014. The patients underwent deglutition analysis, which was performed by otorhinolaryngologists, before and after surgery, and comprised videofluoroscopy and fiberoptic endoscopy. We examined the relationship between imaging studies and swallowing function.

RESULTS

Preoperatively, subjective dysphagia was reported by 2 patients. Videofluoroscopy identified dysmotility of the epiglottis and incomplete closure of the laryngeal inlet in 2 patients, with contrast medium entering the larynx, and endoscopy identified food residue in the larynx of 1 patient during swallowing evaluation. Postoperatively, 2 patients with preoperative impaired deglutition showed dysphagia. Imaging examinations of the 2 patients revealed a 10°-reduction in the O-C2 angle of 1 patient, but the angle was unchanged in the other patient.

CONCLUSIONS

To the best of our knowledge, this is the first report to evaluate swallowing function before and after O-C3 arthrodesis. The preoperative O-C2 angle was unchanged after surgery. Impairment of deglutition may be closely associated with air leakage from the oropharynx due to impaired mobility of the soft palate. Because the precise mechanism of dysphagia has not been fully elucidated, further study using dynamic videofluoroscopy and videoendoscopy is needed to examine the swallowing mechanism.

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.

A novel skull clamp positioning system and technique for posterior cervical surgery: clinical impact on cervical sagittal alignment

A prospective radiographic study.The purpose of this study was to analyze whether a novel skull clamp positioning system and technique is useful for obtaining good, quantitative cervical sagittal alignment during posterior cervical surgery.Different surgical procedures depend on cervical spine positioning. However, maneuver of the device and cervical position depends on the skill of the operator.This study included 21 male and 10 female patients with cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament of the cervical spine, undergoing posterior cervical surgery using the novel skull clamp positioning system. The average patient age was 68.6 years (range: 56-87 years). The novel system has a scale to adjust the neck position and to enable intended cervical sagittal alignment. First, the patient was placed on the operating table in the prone position with preplanned head-neck sagittal alignment (neutral position in general). The head was rotated sagittally, and the head was positioned in the military tuck position with the novel device that was used to widen the interlaminar space. After completing the decompression procedure, the head was rotated again back to the initial preplanned position. During this position change, the scale equipped with the device was useful in determining accurate positions. The C0-C1, C0-C2, C1-C2, C2-C7, and C0-C7 angles were measured on lateral radiographs taken pre-, intra-, and postoperatively.This novel system allowed us to obtain adequate, quantitative cervical sagittal alignment during posterior cervical surgery. There were no clinically significant differences observed between the pre- and postoperative angles for C1-C2 and C2-C7.Sagittal neck position was quantitatively changed during posterior cervical surgery using a novel skull clamp positioning system, enabling adequate final cervical sagittal alignment identical to the preplanned neck 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.

Sleep apnea and cervical spine pathology

PURPOSE

Sleep apnea is a multi-factorial disease with a variety of identified causes. With its close proximity to the upper airway, the cervical spine and its associated pathologies can produce sleep apnea symptoms in select populations. The aim of this article was to summarize the literature discussing how cervical spine pathologies may cause sleep apnea.

METHODS

A search of the PubMed database for English-language literature concerning the cervical spine and its relationship with sleep apnea was conducted. Seventeen published papers were selected and reviewed.

RESULTS

Single-lesion pathologies of the cervical spine causing sleep apnea include osteochondromas, osteophytes, and other rare pathologies. Multifocal lesions include rheumatoid arthritis of the cervical spine and endogenous cervical fusions. Furthermore, occipital-cervical misalignment pre- and post-cervical fusion surgery may predispose patients to sleep apnea.

CONCLUSIONS

Pathologies of the cervical spine present significant additional etiologies for producing obstructive sleep apnea in select patient populations. Knowledge of these entities and their pathophysiologic mechanisms is informative for the clinician in diagnosing and managing sleep apnea in certain populations.

The O-C2 angle established at occipito-cervical fusion dictates the patient's destiny in terms of postoperative dyspnea and/or dysphagia

PURPOSE

We have revealed that the cause of postoperative dyspnea and/or dysphagia after occipito-cervical (O-C) fusion is mechanical stenosis of the oropharyngeal space and the O-C2 alignment, rather than total or subaxial alignment, is the key to the development of dyspnea and/or dysphagia. The purpose of this study was to confirm the impact of occipito-C2 angle (O-C2A) on the oropharyngeal space and to investigate the chronological impact of a fixed O-C2A on the oropharyngeal space and dyspnea and/or dysphagia after O-C fusion.

MATERIALS AND METHODS

We reviewed 13 patients who had undergone O-C2 fusion, while retaining subaxial segmental motion (OC2 group) and 20 who had subaxial fusion without O-C2 fusion (SA group). The O-C2A, C2-C6 angle and the narrowest oropharyngeal airway space were measured on lateral dynamic X-rays preoperatively, when dynamic X-rays were taken for the first time postoperatively, and at the final follow-up. We also recorded the current dyspnea and/or dysphagia status at the final follow-up of patients who presented with it immediately after the O-C2 fusion.

RESULTS

There was no significant difference in the mean preoperative values of the O-C2A (13.0 ± 7.5 in group OC2 and 20.1 ± 10.5 in group SA, Unpaired t test, P = 0.051) and the narrowest oropharyngeal airway space (17.8 ± 6.0 in group OC2 and 14.9 ± 3.9 in group SA, Unpaired t test, P = 0.105). In the OC2 group, the narrowest oropharyngeal airway space changed according to the cervical position preoperatively, but became constant postoperatively. In contrast, in the SA group, the narrowest oropharyngeal airway space changed according to the cervical position at any time point. Three patients who presented with dyspnea and/or dysphagia immediately after O-C2 fusion had not resolved completely at the final follow-up. The narrowest oropharyngeal airway space and postoperative dyspnea and/or dysphagia did not change with time once the O-C2A had been established at O-C fusion.

CONCLUSIONS

The O-C2A established at O-C fusion dictates the patient's destiny in terms of postoperative dyspnea and/or dysphagia. Surgeons should pay maximal attention when establishing the O-C2A during surgery, because their careless decision for the O-C2A may cause persistent dysphagia or a life-threatening consequence. We recommend that the O-C2A in O-C fusion should be kept at least at more than the preoperative O-C2A in the neutral position.

Reduction of atlantoaxial subluxation causes airway stenosis

STUDY DESIGN

A cross-sectional study.

OBJECTIVE

The purpose of this study was to investigate the effect of reduction of anterior atlantoaxial subluxation (AAS) on the oropharyngeal airway space.

SUMMARY OF BACKGROUND DATA

Our previous studies have shown that reduction of the occipito-C2 angle (O-C2A) makes the mandible shift posteriorly, resulting in oropharyngeal airway stenosis, which occasionally causes postoperative dysphagia after occipitocervical fusion. Based on this background, we hypothesized that reduction of AAS would also cause oropharyngeal airway stenosis independent of the O-C2A, because it also shifts the mandible posteriorly. To our knowledge, there are no data demonstrating an association between reduction of AAS and the oropharyngeal airway space.

METHODS

The authors prospectively evaluated 64 patients with rheumatoid arthritis. We analyzed lateral cervical plain radiographs of 5 different positions (neutral, flexion, extension, retraction, and protrusion), and measured the O-C2A, C2-C6 angle, anterior atlantodental interval, anteroposterior distance of the narrowest oropharyngeal airway space (nPAS), and so on. The subjects were classified into 2 groups: group R comprised patients with a "reducible AAS" in dynamic cervical movement, and group N comprised "patients without AAS" patients.

RESULTS

In the multiple regression analysis, the change in the O-C2A was the only significant independent variable related to the percentage change in the nPAS from the neutral position in group N. On the contrary, the change in the anterior atlantodental interval and change in the O-C2A were significantly related to the percentage change in the nPAS in group R. No cases in group N and 7 cases (28%) in group R showed a paradoxical decrease in the nPAS in extension, in which the O-C2A is largest and reduction of AAS is obtained.

CONCLUSION

Reduction of AAS has a negative effect on the oropharyngeal airway space. Therefore, reduction of AAS during occipitocervical fusion may cause postoperative dysphagia despite maintenance of the O-C2A.

Impact of the O-C2 angle on the oropharyngeal space in normal patients

STUDY DESIGN

Radiographic analysis using normal patients.

OBJECTIVE

To analyze the relationship between the cervical alignment and the oropharyngeal space.

SUMMARY OF BACKGROUND DATA

Few clinical studies stress the effect of the occipito-C2 (O-C2) alignment on the oropharyngeal space. A previous study showed dysphagia and/or dyspnea after occipitocervical fusion was caused by oropharyngeal stenosis resulting from O-C2 fixation in a flexed position. Other independent researchers showed that development or improvement of obstructive sleep apnea in rheumatoid arthritis patients was related to the O-C2 alignment. However, there are limited basic data demonstrating the relationship between the O-C2 alignment and the oropharyngeal space.

METHODS

Plain lateral cervical radiographs in five tested positions--neutral, flexion, extension, protrusion, and retraction--of 40 asymptomatic volunteers were collected. The O-C2 angle, the C2-C6 angle, and the anterior-posterior distance of the narrowest oropharyngeal airway space (nPAS) were measured, and the changes in value from the neutral to the other four positions were calculated for each patient.

RESULTS

According to the multiple regression analysis, there was an extremely strong linear correlation of the change in the O-C2 angle with the percentage change in the nPAS. Referring to the multiple regression analysis, a decrease of 10° in the O-C2 angle caused a 37% reduction in the nPAS in the neutral position. In contrast, no significant correlation was found between the change in the C2-C6 angle and the percentage change in the nPAS.

CONCLUSION

Our results show the impact of the O-C2 angle on the oropharyngeal space. This knowledge will be useful for the diagnosis and treatment of the upper cervical lesion combined with the upper airway stenosis, and for the determination of the optimal fixation angle in occipitocervical fusion.

Depression in patients with rheumatoid arthritis: description, causes and mechanisms

Two sets of contributory factors to depression among patients with rheumatoid arthritis (RA) are generally examined - the social context of the individual and the biologic disease state of that person's RA. This article will review the evidence for both. RA affects patients both physically and psychologically. Comorbid depression is common with RA and leads to worse health outcomes. Low socioeconomic status, gender, age, race/ethnicity, functional limitation, pain and poor clinical status have all been linked to depression among persons with RA. Systemic inflammation may also be associated with, cause, or contribute to depression in RA. Understanding the socioeconomic factors, individual patient characteristics and biologic causes of depression in RA can lead to a more comprehensive paradigm for targeting interventions to eliminate depression in RA.