Long-Term Results of Occipitothoracic Fusion Surgery in RA Patients with Destruction of the Cervical Spine

Effects of Head and Neck Alignment and Pharyngeal Anatomy on Epiglottic Inversion During Swallowing in Dysphagic Patients

The effects of head and neck alignment and pharyngeal anatomy on epiglottic inversion remain unclear. This study investigated the factors involved in epiglottic inversion, including head and neck alignment and pharyngeal anatomy, in patients with dysphagia. Patients with a chief complaint of dysphagia and who underwent videofluoroscopic swallowing study at our hospital from January to July 2022 were enrolled. They were divided into three groups based on the degree of epiglottic inversion as the complete-inversion (CI), partial-inversion (PI), and non-inversion group (NI) groups. Data were compared among the three groups; a total of 113 patients were analyzed. The median age was 72.0 (IQR: 62.0-76.0) years; 41 (36.3%) and 72 (63.7%) were women and men, respectively. There were in 45 (39.8%) patients in the CI, 39 (34.5%) in the PI, and 29 (25.7%) in the NI groups, respectively. Single-variable analysis revealed significant relation to epiglottic inversion of Food Intake LEVEL Scale score, penetration-aspiration score with 3-mL thin liquid bolus, epiglottic vallecula and pyriform sinus residue, hyoid position and displacement during swallowing, pharyngeal inlet angle (PIA), epiglottis to posterior pharyngeal wall distance, and body mass index. Logistic regression analysis with complete epiglottic inversion as the dependent variable revealed the X coordinate at maximum hyoid elevation position during swallowing and PIA as significant explanatory variables. These results suggest that epiglottic inversion is constrained in patients with dysphagia who have poor head and neck alignment or posture and a narrow pharyngeal cavity just before swallowing.

Severe dysphagia after a posterior cervical spine fusion at the C1–C3 level and its improvement after correction surgery for malalignment: a case report

Background

The development of dysphagia and trismus following posterior C1–C3 fusion is rare compared to occipitocervical fusion, and there are very few reports in the literature.

Case presentation

A 75-year-old Thai man who had an extradural tumor at the C1/C2 level developed severe dysphagia and trismus immediately after tumor resection and C1–C3 fusion. During the surgery for malalignment correction, the C1–C2 screws were re-aligned into an increased lordotic position. The symptoms resolved immediately post-surgery.

Conclusions

Short upper cervical fusion can produce trismus and dysphagia in a relatively flexed position. Preoperative planning should be individualized based on the patient’s resting neutral alignment to prevent complications.

A new radiological parameter as a predictor of dysphagia based on oro-pharyngeal stenosis in a cohort of pediatric patients undergoing mal-reduced C1-2 pedicle screw fixation

PURPOSE

C1 pedicle screw technique showed further advantages since it avoids the negative results from the sacrificed range of motion of the atlantooccipital joint compared to the occipitocervical fusion. However, some intractable complications are unavoidable. In the pediatric population, dysphagia after the atlantoaxial fixation can be accidentally serious. We aimed to determine the incidence of dysphagia in the pediatric population's cohort and its radiological predictor.

METHODS

Between January 2010 and August 2018, this retrospective study included 42 pediatric patients with atlantoaxial dislocation due to trauma. They were followed up with an average duration of 8 years (range 5-18 years). Twenty-seven were males and 15 females with a mean age of 8.2 years (range 5-15 years) when undergoing operations. Patients were classified according to the presence of postoperative dysphagia according to the Bazaz dysphagia grading scale. The measurements, including pre- and postoperative CVT/NSL, O-C2, and C2-C7 sagittal angles, were performed.

RESULTS

26.2% of the patients (11/42) experienced postoperative dysphagia. A significant difference in the postoperative CVT/NSL (115.2 ± 13.2 vs.134.8 ± 17.3, P = 0.002), ΔCVT/NSL (7.0 ± 11.2 vs. 20.3 ± 10.5, P = 0.001), ΔO-C2 (- 3.2 ± 5.8 vs. 2.1 ± 5.1, P = 0.026), postoperative nPAS (9.4 ± 3.7 vs. 12.6 ± 4.2, P = 0.031) and ΔPAS (- 1.5 ± 4.1 vs. 2.0 ± 3.5, P = 0.010) between dysphagia group and non-dysphagia group were found. Adjustment for age, gender, and BMI, the multivariate logistic analysis showed that ΔCVT/NSL < 8.35° (OR = 5.23; 95% CI 4.97-5.50; P = 0.001) and ΔO-C2 (OR = 3.34; 95% CI 3.17-3.51; P = 0.001) remained associated with the occurrence of the swallowing problems.

CONCLUSION

In comparison with ΔO-C2, ΔCVT/NSL might better predict postoperative dysphagia in children.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Bilateral persistent intersegmental artery in a patient with posterior atlantoaxial subluxation after subaxial cervical laminoplasty

INTRODUCTION AND IMPORTANCE

To summarize the clinical manifestations and treatment of bilateral persistent first intersegmental artery (PFIA) in a patient with posterior subluxation of atlantoaxial joint.

CASE PRESENTATION

A-85-year-old woman with a two-months history of aggravating of gait disturbance and finger clumsiness was referred to our hospital. Magnetic resonance imaging revealed posterior subluxation of the atlantoaxial joint and spinal cord compression at C1 level. Three-dimensional computed tomography angiography (CTA) of cervical spine showed bilateral PFIA and left side high-riding VA. Because of the high risk of vertebral artery injury with posterior arch resection and lateral mass screw insertion due to the presence of PFIA, as well as the bony fragility of the cervical spine and the fact that the posterior atlantoaxial subluxation was reduced in the flexed position, the posterior occipito-thoracic fixation without posterior arch resection in the mildly flexed cervical position was underwent. The postoperative course was uneventful and her neurological symptoms improved gradually after surgery.

CLINICAL DISCUSSION

PFIA is a very rare condition representing between 0.01 % and 1.8 %. Most patients with this condition have a unilateral persistent segmental artery, but in a small minority of cases it occurs bilaterally. It may be more difficult to resect of posterior arch or insert the C1 lateral mass screw in cases of PFIA.

CONCLUSION

The best way to avoid IVAI may be careful examining the abnormal running of VA preoperatively especially on 3D-CT of cervical spine with arteriography and not to choose a technique with a high risk of VA injury.

Analysis of risk factors for postoperative dysphagia after C1-2 fusion

Objective

This study aimed to analyze the risk factors for dysphagia after C1-2 fusion in patients with C1-2 junction diseases.

Summary of the background data

Dysphagia is a common postoperative complication of posterior C1-2 junction surgery. The incidence is 9.5% to 26.3%. However, the etiopathogenisis of postoperative dysphagia remains controversial.

Methods

This retrospective study included patients who underwent C1-2 fusion from January 2016 to January 2020. The patients were divided into dysphagia group and control group in accordance with the Bazaz R dysphagia scoring system. The patients' age, gender, BMI(body mass index), cause of disease, and changes in the C01cobb, C02cobb, C12cobb, C27cobb, dC02cobb, dC01cobb, dC12cobb, d C27cobb angles before and after operation, were recorded. The parameters and changes were compared to analyze the risk factors for dysphagia after C1-2 fusion.

Results

65 cases (15, with dysphagia; 50, without dysphagia) were included. The incidence of postoperative dysphagia was 23%. The differences in age, gender ratio, and BMI between the two groups were not significant (P > 0.05). The differences among postoperative C12 (29.8° ± 11.24° vs. 20.46° ± 13.39°), postoperative C27cobb (10.56° ± 8.53° vs. 20.21° ± 13.21°), and dC12cobb (9.49° ± 5.16° vs. 1.07° ± 12.44°) between the two groups were significant (P < 0.05). Multiple logistic regression analyses revealed that dC12cobb > 5° was a significant independent risk factor for postoperative dysphagia, And preoperative C27cobb was a preventive factor of postoperative dysphagia.

Conclusions

Dysphagia after the C1-2 fusion was common. dC02cobb and dC12cobb were the significant independent risk factors for postoperative dysphagia. Preoperative c27cobb was a preventive factor of dysphagia.

Considerations in revising occipitocervical fixation for dysphagia

Background:

Dysphagia after occipitocervical fixation (OCF) is a complex phenomenon and revision surgery in this context involves difficult decision-making. The pathogenesis is explored and surgical strategies discussed. A surgical strategy that has not been described before in the management of this condition, is discussed with two illustrative cases.

Methods:

Two cases are presented where dysphagia occurred after OCF for C1/C2 instability. The preoperative imaging was not available to determine whether the optimal craniocervical angle had been achieved. Both had revision surgery with removal of the cranial fixation and fusion to the atlas instead. One of the cases had the revision surgery more than 10 years after the original OCF.

Results:

The dysphagia recovered after the revision surgery in both cases. The patients gained weight and reported more satisfaction with their posture and head movements compared to before the revision surgery. There was no head ptosis and instead, patients reported better forward gaze and head position.

Conclusion:

In cases of C1/C2 instability, it is preferable to perform C1/C2 fusion rather than OCF. If performing an OCF, care must be taken to fix the head at the same O-C2 angle as preoperative. When an OCF done for C1 C2 instability ends up causing dysphagia, it is feasible and effective to shorten the rostral construct by removing the cranial fixation and fusing to C1 instead.

Predictive ability of pharyngeal inlet angle for the occurrence of postoperative dysphagia after occipitocervical fusion

Background

PIA has been proven to be a predictor for postoperative dysphagia in patients who undergo occipitospinal fusion. However, its predictive effect for postoperative dysphagia in patients who undergo OCF is unknown. The aim of this study was to evaluate the predictive ability of the pharyngeal inlet angle (PIA) for the occurrence of postoperative dysphagia in patients who undergo occipitocervical fusion (OCF).

Methods

Between 2010 and 2018, 98 patients who had undergone OCF were enrolled and reviewed. Patients were divided into two groups according to the presence of postoperative dysphagia. Radiographic parameters, including the atlas-dens interval (ADI), O-C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa), C2 tilting angle (C2Ta), C2-7 angle (C2-7a), PIA and narrowest oropharyngeal airway space (nPAS), were measured and compared. Simple linear regression and multiple regression analysis were used to evaluate the radiographic predictors for dysphagia. In addition, we used PIA = 90° as a threshold to analyze its effect on predicting dysphagia.

Results

Of the 98 patients, 26 exhibited postoperative dysphagia. Preoperatively, PIA in the dysphagia group was significantly higher than that in the nondysphagia group. We detected that O-C2a, O-EAa, PIA and nPAS all decreased sharply in the dysphagia group but increased slightly in the nondysphagia group. The changes were all significant. Through regression analyses, we found that PIA had a similar predictive effect as O-EAa for postoperative dysphagia and changes in nPAS. Additionally, patients with an increasing PIA exhibited no dysphagia, and the sensitivity of PIA <90° in predicting dysphagia reached 88.5%.

Conclusions

PIA could be used as a predictor for postoperative dysphagia in patients undergoing OCF. Adjusting a PIA level higher than the preoperative PIA level could avoid dysphagia. For those who inevitably had decreasing PIA, preserving intraoperative PIA over 90° would help avert postoperative dysphagia.

Trial registration

This trial has been registered in the Medical Ethics Committee of West China Hospital, Sichuan University. The registration number is 762 and the date of registration is Sep. 9 th, 2019.

Predictive abilities of O-C2a and O-EAa for the development of postoperative dysphagia in patients undergoing occipitocervical fusion

BACKGROUND CONTEXT

Dysphagia is a common postoperative complication in patients undergoing occipitocervical fusion (OCF). Previous studies had proposed the use of two measures-the occipital to C2 angle (O-C2a) and the occipital and external acoustic meatus to axis angle (O-EAa)-to predict postoperative dysphagia after OCF. However, these studies had small sample sizes and the predictive abilities of both measures are still not clear.

PURPOSE

To evaluate the predictive ability of O-EAa and O-C2a for dysphagia after OCF.

STUDY DESIGN

A retrospective clinical study.

PATIENT SAMPLE

A total of 109 consecutive patients who had undergone OCF.

OUTCOME MEASURES

Presence of postoperative dysphagia, O-C2a, C2 tilting angle (C2Ta), O-EAa, and the narrowest oropharyngeal airway space (nPAS).

METHODS

Between April 2010 and June 2018, 109 consecutive patients who had undergone OCF were reviewed. Patients were divided into two groups according to the presence of postoperative dysphagia. Radiographic measurements, including O-C2a, C2Ta, O-EAa, and nPAS, were evaluated at preoperative and 1 month postoperative and the findings were compared. Simple linear regression was used to measure the correlations between the parameters and the presence of dysphagia, and the correlations within the parameters. Multiple regression analysis was used to examine the variables that affected the change of nPAS (dnPAS%). Sensitivity and specificity analyses were used to evaluate the effectiveness of the previously proposed measures ("O-C2a change≤-5°" and "postoperative O-EAa<100°") for prediction of post-OCF dysphagia.

RESULTS

The incidence of dysphagia after OCF was 26.6% (29/109). Preoperative values for the radiographic parameters were similar between patients with and without dysphagia. In the dysphagia group, both O-C2a and O-EAa values showed a dramatic decrease after surgery, which was accompanied by a decrease in nPAS. Postoperative O-C2a, O-EAa, and nPAS in the dysphagia group were significantly smaller than those in the nondysphagia group (p<.05). The changes in O-EAa, O-C2a, and nPAS showed a linear correlation with the presence of dysphagia (p<.05). In addition, linear correlations were found between two of the three parameters. Multiple regression showed the change of O-C2a and O-EAa were significant predictors for dnPAS% (β=0.200, p=.022 and β=0.549, p=.000). The sensitivity and specificity of "O-C2a change≤-5°" in predicting dysphagia were 75.9% and 80.0% respectively, and those of "postoperative O-EAa<100°" were 75.9% and 62.5%, respectively. However, the sensitivity of the combination of these two values in predicting postoperative dysphagia was as high as 96.6%.

CONCLUSION

Both O-EAa and O-C2a could be critical predictors for postoperative dysphagia. During surgery, ensuring that the O-EAa exceeds 100° and simultaneously avoiding an O-C2a reduction greater than 5° could effectively avert postoperative dysphagia.

Association Between the Severity of Dysphagia and Various Parameters of the Cervical Spine; Videofluoroscopic Analysis in Neutral and Retraction Position of the Normal Volunteers

STUDY DESIGN

Videoflurographic swallowing study in asymptomatic volunteers.

OBJECTIVE

The purpose of this study was to investigate the relationship between the severity of dysphagia and various parameters of the subjects.

SUMMARY OF BACKGROUND DATA

Occipitocervical fixation is associated with several potential complications. Malalignment of craniovertebral junction and associated dysphagia have been well described in the literature. However, there has been little attention given to investigate the association between the degree of swallowing dysfunction and various patient's parameters.

METHODS

Thirty-nine healthy asymptomatic volunteers, 18 males and 21 females, were enrolled in this study. Based on videofluorographic swallowing study (VFSS), two scoring systems of swallowing dysfunction (dysphagia rating scale [DRS], dysphagia outcome and severity scale [DOSS]) were measured in neutral and retraction position. Multiple linear regression analysis was performed to evaluate the relationship between the degree of swallowing dysfunction and various factors of the subjects such as radiological and clinical parameters.

RESULTS

There was statistically significant correlation between DRS and DOSS (r = -0.354, P < 0.05). Multiple regression analysis showed that there was a significant association of the dysphagia severity (DRS and DOSS) with the percentile change of the narrowest oropharyngeal diameter (OD) (%dn OD) (r = 0.121, P < 0.01 and r = 0.020, P < 0.01, respectively). Percentile change of OD (neutral and retraction position) was positively associated with the difference of C0-2 angle (r = 1.676, P < 0.01). None of the other variables such as age, sex, C0-1 angle, C1-2 angle, and C2-7 angle were significantly associated with the degree of dysphagia or %dn OD.

CONCLUSION

This study demonstrated that the severity of dysphagia is significantly associated with the percentile change of OD and the C0-2 angle has considerable effect on the OD after O-C fusion. Therefore, C0-2 angle could be the most critical radiological parameter not only for predicting the stricture of oropharyngeal space but also for preventing postoperative dysphagia.

LEVEL OF EVIDENCE

4.

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.

The impact of the difference in O-C2 angle in the development of dysphagia after occipitocervical fusion: a simulation study in normal volunteers combined with a case-control study

BACKGROUND CONTEXT

Dysphagia has been recognized as one of the most serious complications after occipitocervical fusion (OCF), and the difference between postoperative and preoperative O-C2 angle (dO-C2A) was proposed to be an indicator in predicting and preventing dysphagia. Therefore, to prevent postoperative dysphagia, previous studies recommend that surgeons should correct the O-C2 angle (O-C2A) during surgery if the occipitocervical alignment was in an excessively flexed position. However, until now, there was no explicit indicator of the condition in which surgeons should adjust the patient's O-C2A during surgery.

PURPOSE

One of the purposes of this study was to explore the threshold of dO-C2A between dysphagia and normal swallowing by a simulation study. The other aim was to evaluate the validity of the threshold of dO-C2A in predicting dysphagia after OCF via a case-control study.

STUDY DESIGN

This is a simulation study combined with a retrospective case-control study.

PATIENT SAMPLE

Thirty volunteers were enrolled in the simulation study. Thirty-four consecutive patients who underwent OCF between September 2011 and September 2016 were included in the case-control study.

OUTCOME MEASURES

The outcome measures included O-C2A, C2-7 angle (C2-7A), atlantodental interval (ADI), the narrowest oropharyngeal airway space (nPAS), the rate of change in dnPAS (%dnPAS), and the prevalence of postoperative dysphagia.

MATERIALS AND METHODS

In the simulation study, each volunteer received two lateral x-rays of their cervical spine in neutral position and dysphagia position, respectively. We compared the radiographic parameters in neutral and dysphagia positions. The cumulative frequency diagram of dO-C2A in the dysphagia position was analyzed to identify the threshold of dO-C2A in the development of dysphagia. In the case-control study, these 34 patients were divided into two groups according to the threshold of dO-C2A identified in the simulation study. The impact of radiographic parameters on nPAS was analyzed. The prevalence of postoperative dysphagia between the two groups was compared to evaluate the validity of the threshold of dO-C2A in predicting dysphagia after OCF.

RESULTS

In the simulation study, the mean O-C2A and nPAS in the dysphagia position were significantly smaller than in the neutral position (p<.05). There was no significant difference between the mean C2-7A in the neutral and dysphagia positions (p>.05). There was a significant positive correlation between dO-C2A and dnPAS (p<.05). A dO-C2A of -5° delineated the threshold between normal swallowing and dysphagia. In the case-control study, multiple regression analysis showed that dO-C2A was the only significant variable correlated with dnPAS (β=0.769, p<.001). Among the reviewed 34 patients, the incidence of dysphagia was 17.6% (6/34) at 2 weeks after surgery and decreased over time to 11.8% (4 of 34) at the last follow-up. There was also a significant positive correlation between the dO-C2A and dnPAS (p<.05). The prevalence of dysphagia after OCF in patients with dO-C2A<-5° was as high as 66.7% (6/9). However, there was no patient suffering from dysphagia in patients with dO-C2A≥-5°.

CONCLUSION

The present study showed that the dO-C2A should be a key factor in the development of postoperative dysphagia after OCF. A dO-C2A of -5° could be the threshold between dysphagia and normal swallowing. Furthermore, to avoid dysphagia, surgeons should correct the O-C2A just before the final occipitocervical fixation if the checked dO-C2A during surgery is less than -5°.

Occipital and external acoustic meatus to axis angle as a predictor of the oropharyngeal space in healthy volunteers: a novel parameter for craniocervical junction alignment

BACKGROUND CONTEXT

The occipito-C2 angle (O-C2a) influences the oropharyngeal space. However, O-C2a has several limitations. There is no normal value of O-C2a because of the wide individual variations, and O-C2a does not reflect translation of the cranium to the axis, another factor influencing the oropharyngeal space in patients with atlantoaxial subluxation.

PURPOSE

The objective of this study was to propose a novel parameter that accounts for craniocervical junction alignment (CJA) and the oropharyngeal space.

STUDY DESIGN

This is a post hoc analysis of craniocervical radiological parameters from another study.

PATIENT SAMPLE

Forty healthy volunteers were included in the study.

OUTCOME MEASURES

Craniocervical measurement parameters included the occipital and external acoustic meatus to axis angle (O-EAa), the C2 tilting angle (C2Ta), O-C2a, and the anterior-posterior distance of the narrowest oropharyngeal airway space (nPAS).

MATERIALS AND METHODS

We collected 40 healthy volunteers' lateral cervical radiographs in neutral, flexion, extension, protrusion, and retraction positions. We measured O-C2a, C2Ta (formed by the inferior end plate of C2 and a line connecting the external acoustic meatus and the midpoint of the inferior end plate of C2 [EA-line]), O-EAa (formed by the McGregor line and the EA-line), and nPAS. We evaluated the inter-rater and intrarater reliability of O-EAa and C2Ta, and the associations between each of the measured parameters.

RESULTS

The inter-rater and intrarater reliabilities of measuring O-EAa and C2Ta were excellent. The neutral position O-EAa values remained in a narrower range (mean±standard deviation, 90.0°±5.0°) than O-C2a (15.6°±6.7°) (Levene test of equality of variances, p=.044). In the linear mixed-effects models, sex, O-C2a, C2Ta, and O-EAa were significantly associated with nPAS. The marginal R² values for the mixed-effect models, which express the variance explained by fixed effects, were 0.605 and 0.632 for the O-C2a and O-EAa models, respectively. In all models, the subaxial alignment (C2-C6a) had no significant association with nPAS.

CONCLUSIONS

The O-EAa may be a useful parameter of CJA with several advantages over O-C2a, including less individual variation, easier visual recognition during surgery, and improved prediction of postoperative nPAS after occipitocervical fusion.

Influence of neck postural changes on cervical spine motion and angle during swallowing

Occipitocervical (OC) fixation in a neck retraction position could be dangerous due to the risk of postoperative dysphagia. No previous study has demonstrated an association between the cervical posture change and cervical spine motion/angle during swallowing. So, we aimed to analyze the influence of neck posture on the cervical spine motion and angle change during swallowing.Thirty-seven asymptomatic volunteers were recruited for participation this study. A videoflurographic swallowing study was performed in the neutral and retracted neck posture. We analyzed the images of the oral and pharyngeal phases of swallowing and compared the angle and the position changes of each cervical segment.In the neutral posture, C1 and C2 were flexed, while C5, C6, and C7 were extended. C3, C4, C5, C6, and C7 moved posteriorly. All cervical levels, except for C5, moved superiorly. In the retraction posture, C0 and C1 were flexed, while C6 was extended during swallowing. All cervical levels moved posteriorly. C1, C2, C3, and C4 moved superiorly. The comparison between 2 postures shows that angle change is significantly different between C0, C2, and C5. Posterior translation change is significantly different in the upper cervical spine (C0, C1, and C2) and C7. Superior movement is significantly different in C0.C0 segment is most significantly different between neutral and retraction posture in terms of angle and position change. These data suggest that C0 segment could be a critical level of compensation that allows swallowing even in the retraction neck posture regarding motion and angle change. So, it is important not to do OC fixation in retraction posture. Also, sparing C0 segment could provide some degree of freedom for the compensatory movement and angle change to avoid dysphagia after OC fixation.

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.

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.

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.

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.

Dyspnea and dysphagia from upper airway obstruction after occipitocervical fusion in the pediatric age group

Upper airway obstruction resulting from overflexion of the craniocervical junction after occipitocervical fusion is a rare but potentially life-threatening complication and is associated with morbidity. The authors retrospectively reviewed the medical records and diagnostic images of 2 pediatric patients who underwent occipitocervical fusion by the Neuro-Spine Program at Texas Children's Hospital and experienced dyspnea and/or dysphagia from new upper airway obstruction in the postoperative period. Patient demographics, operative data, and preoperative and postoperative occiput-C2 angles were recorded. A review of the literature for similar complications after occipitocervical fusion was performed. A total of 13 cases of prolonged upper airway obstruction after occipitocervical fusion were analyzed. Most of these cases involved adults with rheumatoid arthritis. To the best of the authors' knowledge, there have been no previous reports of prolonged upper airway obstruction in children after an occipitocervical fusion. Fixation of the neck in increased flexion (-18° to -5°) was a common finding among these adult and pediatric cases. The authors' cases involved children with micrognathia and comparatively large tongues, which may predispose the oropharynx to obstruction with even the slightest amount of increased flexion. Close attention to a satisfactory fixation angle (occiput-C2 angle) is necessary to avoid airway obstruction after an occipitocervical fusion. Children with micrognathia are particularly sensitive to changes in flexion at the craniocervical junction after occipitocervical fixation.

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.

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.

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.

Neurological improvement and prognosis after occipito-thoracic fusion in patients with mutilating-type rheumatoid arthritis

INTRODUCTION

Mutilating-type rheumatoid arthritis, the most aggressive type of rheumatoid arthritis, is frequently associated with destructive cervical involvement, both at the high-cervical and subaxial levels, causing significant neurological deficit, and their natural course of the disease and the survival are discouraging. For such cases, we have been actively performing occipito-thoracic fusion since 1991. Although medical treatment for rheumatoid patients has represented a marked improvement, it could not treat all of these patients because of several reasons. Therefore, it is still important to evaluate the past treatment results.

METHODS

We investigated the neurological improvement and prognosis in 51 mutilating-type rheumatoid arthritis patients who underwent occipito-thoracic fusion between 1991 and 2010. The neurological status was evaluated using modified Ranawat classification; class IIIB was subdivided into IIIBa (able to sit upright) and IIIBb (bedridden).

RESULTS

The preoperative neurologic status was IIIBa in 19 patients and IIIBb in 17 patients. 15 of the 19 patients with class IIIBa improved to being able to walk (79 %), whereas only 3 of the 17 patients with class IIIBb improved to being able to walk (18 %) after surgery. Of the 51 patients, 28 died during follow-up; the mean age at death was 67.2 years. The postoperative 5- and 10-year survival rates were 60.3 and 26.4 %, respectively.

CONCLUSION

The neurological improvement and prognosis after surgery was poorer in class IIIBb patients than in the other patient groups. Occipito-thoracic fusion can improve the neurological symptoms and prognosis. However, early surgical intervention is recommended, before a patient becomes bedridden (class IIIBb).

Stable reconstruction using halo vest for unstable upper cervical spine and occipitocervical instability

INTRODUCTION

Upper cervical or occipitocervical disorders such as rheumatoid arthritis present as atlantoaxial subluxation, vertical subluxation of the axis, and subaxial subluxation, which produce myelopathy and severe pain. In such cases, occipitocervical reconstruction surgery may be indicated, and several reports have described reduction of subluxation by fixing the halo vest before this surgery.

PURPOSE

The purpose of this study was to evaluate the efficacy of using the halo vest before the surgery for unstable upper cervical spine and for occipitocervical instability.

METHODS

Twenty-eight patients (9 men and 19 women; mean age, 61.8 years at surgery) who presented with atlantoaxial or occipitocervical fusion were studied. In all cases, the halo vest was fixed in the conscious condition, and subluxation was reduced before the surgery. The mean follow-up period was 45 months. Roentgenologic measurement and clinical evaluation were performed before the surgery and at the final follow-up.

RESULTS

Using the halo vest resulted in significant reductions in the atlantodental interval, the space available for the spinal cord, and the Ranawat value (p < 0.05), and these were maintained until the final follow-up. The mean Japanese Orthopedic Association score significantly improved from 9.5 before surgery to 12.2 at the final follow-up (p = 0.01). Nineteen cases (68%) improved by more than 1 grade by Ranawat's classification after surgery and 16 cases (57%) maintained the same at the follow-up visit.

CONCLUSION

Conscious preoperative reduction using the halo vest for occipitocervical disorders is a useful and safe technique.

Occipitocervicothoracic stabilization in pediatric patients

OBJECT

Although rarely encountered, pediatric patients with severe cervical spine deformities and instability may occasionally require occipitocervicothoracic instrumentation and fusion. This case series reports the experience of 4 pediatric centers in managing this condition. Occipitocervical fixation is the treatment of choice for craniocervical instability that is symptomatic or threatens neurological function. In children, the most common distal fixation level with modern techniques is C-2. Treated patients maintain a significant amount of neck motion due to the flexibility of the subaxial cervical spine. Distal fixation to the thoracic spine has been reported in adult case series. This procedure is to be avoided due to the morbidity of complete loss of head and neck motion. Unfortunately, in rare cases, the pathological condition or highly aberrant anatomy may require occipitocervical constructs to include the thoracic spine.

METHODS

The authors identified 13 patients who underwent occipitocervicothoracic fixation. Demographic, radiological, and clinical data were gathered through retrospective review of patient records from 4 institutions.

RESULTS

Patients ranged from 1 to 14 years of age. There were 7 girls and 6 boys. Diagnoses included Klippel-Feil, Larsen, Morquio, and VATER syndromes as well as postlaminectomy kyphosis and severe skeletal dysplasia. Four patients were neurologically intact and 9 had myelopathy. Five children were treated with preoperative traction prior to instrumentation; 5 underwent both anterior and posterior spinal reconstruction. Two patients underwent instrumentation beyond the thoracic spine. Allograft was used anteriorly, and autologous rib grafts were used in the majority for posterior arthrodesis. Follow-up ranged from 0 to 43 months. Computed tomography confirmed fusion in 9 patients; the remaining patients were lost to follow-up or had not undergone repeat imaging at the time of writing. Patients with myelopathy either improved or stabilized. One child had mild postoperative unilateral upper-extremity weakness, and a second child died due to a tracheostomy infection. All patients had severe movement restriction as expected.

CONCLUSIONS

Occipitocervicothoracic stabilization may be employed to stabilize and reconstruct complex pediatric spinal deformities. Neurological function can be maintained or improved. The long-term morbidity of loss of cervical motion remains to be elucidated.

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.

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.

O-C2 angle as a predictor of dyspnea and/or dysphagia after occipitocervical fusion

STUDY DESIGN

A retrospective clinical study.

OBJECTIVE

To confirm the impact of the O-C2 angle on dyspnea and dysphagia after posterior occipitocervical (O-C) fusion.

SUMMARY OF BACKGROUND DATA

Dyspnea and dysphagia are complications of posterior O-C fusion with malalignment, and may be prolonged or occasionally serious. However, it is difficult to select a safe alignment during surgery, and no indicators of the appropriate alignment have been available to preclude these complications.

METHODS

The authors retrospectively reviewed 29 consecutive patients who had undergone O-C or occipitocervicothoracic fusion between 2003 and 2008. Data were analyzed for O-C2 angles on plain radiographs and the axial computed tomographic cross-sectional areas of the oropharynx just cranial to the epiglottis before and after surgery. The patients were grouped according to whether they developed postoperative dyspnea and/or dysphagia (group A) or not (group B).

RESULTS

After surgery, 4 patients complained of dysphagia, and 1 patient had dyspnea and dysphagia, although they had all undergone short O-C fusions. The difference in the O-C2 angle (dOC2A = postoperative O-C2 angle--preoperative O-C2 angle) and the percentage change in the cross-sectional area of the oropharynx (S) before and after surgery (% dS) were linearly correlated. Both dOC2A and % dS were significantly lower in group A than in group B. All patients with dOC2A of less than -10 degrees showed % dS of less than -40%, and developed dyspnea and/or dysphagia after surgery. Conversely, no patients with positive dOC2A developed these complications.

CONCLUSION

The O-C2 angle has considerable impact on dyspnea and/or dysphagia after O-C fusion. The O-C2 angle is easily measured during surgery and can be a practical index with which to avoid postoperative dyspnea and dysphagia.

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.

Mediastinal migration of distal occipito-thoracic instrumentation

We present the occurrence and management of mediastinal migration of the distal aspect of a posterior occipito-thoracic screw-rod construct. No similar occurrence was found in the literature. This event occurred following an emergency tracheotomy (requiring neck hyperextension) in a patient with severe rheumatoid arthritis, who had previously undergone decompression and an Occiput-T2 instrumented fusion for cranio-cervical and sub-axial cervical spine instability. Imaging showed fracture-subluxation of T1/2 and T2/3 with the bilateral C7, T1 and T2 screws in the mediastinum causing tracheal and esophageal compression. Removal of the instrumentation, decompression (T2 corpectomy) and construct revision down to T10 was safely performed from a posterior approach. Severe osteoporosis, some pre-existing screw loosening and hyperextension of the neck were the predisposing factors of this near catastrophic event. By staying directly posterior to the rod and following the fibrous tract already created, the instrumentation was safely removed from the mediastinum.

Upper-airway obstruction after short posterior occipitocervical fusion in a flexed position

STUDY DESIGN

Case report.

OBJECTIVE

To stress the importance of the fusion angle of the occipitocervical spine based on an unusual case of upper-airway obstruction after a posterior fusion from the occipital bone to the second cervical vertebra (O-C2) in a flexed position.

SUMMARY OF BACKGROUND DATA

It is well known that cervical malalignment after occipito-cervicothoracic fusion may cause dysphagia or, rarely, dyspnea. However, to the best of our knowledge, there have been no previous English reports of prolonged upper-airway obstruction after an O-C2 fusion.

METHODS

We present the case of a 77-year-old woman with rheumatoid arthritis, who developed an upper-airway obstruction immediately after an O-C2 fusion. She was reintubated immediately and extubated the next day. She again suffocated suddenly 3 days after surgery, and a tracheotomy was performed. Suspecting that the main cause of the airway obstruction was not only pharyngeal edema, but also the fixture of the upper cervical angle in a flexed position, we changed the angle to the neutral position 14 days after surgery.

RESULTS

After revision surgery, the upper-airway obstruction disappeared.

CONCLUSION

An adequate fixation angle is necessary to avoid airway obstruction after an occipitocervical fusion, even for short upper cervical fusions, especially in patients with rheumatoid arthritis.