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

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.

Sequential sagittal alignment changes in the cervical spine after occipitocervical fusion

BACKGROUND

There are few studies regarding sequential changes in the sagittal alignment of the upper and lower cervical regions of the spine after occipitocervical fusion (OCF). In addition, no comparisons of cervical sagittal alignment (CSA) between patients with craniocervical junction disorders (CJDs) and normal populations have been reported.

AIM

To compare the CSA of patients with CJDs with that of normal controls and investigate the sequential changes in the CSA of the upper and lower cervical spine after OCF.

METHODS

Eighty-four patients who underwent OCF (OCF group) and 42 asymptomatic volunteers (control group) were included. Radiographic parameters, including the occipital to C2 angle (O-C2a), occipital and external acoustic meatus to axis angle (O-EAa), C2–7 angle (C2-7a), and pharyngeal inlet angle (PIA), were measured and compared pre- and postoperatively. The correlations among the parameters were analyzed using Pearson’s correlation test.

RESULTS

The O-C2a and PIA of the OCF group were smaller than those of the control group, while their O-EAa and C2-7a values were larger than those of the normal controls. There were no significant differences in O-C2a, C2-7a, or PIA in the OCF group at baseline, 1 mo, or the final follow-up after surgery. The Pearson’s correlation results showed that there were significant correlations between the O-C2a and C2Ta, C2-7a, C2-7 sagittal vertical axis (SVA), and PIA at 1 mo after OCF surgery and between O-C2a and O-EAa, C2Ta, C2-7a, C2-7 SVA, and PIA at the final follow-up.

CONCLUSION

Patients with CJDs have a more kyphotic upper CSA and a more lordotic lower CSA than normal controls. The effectiveness of OCF surgery in restoring CSA may be limited by the realignment of the craniocervical junction being neglected. The reduction in O-C2a after OCF surgery may increase C2-7a and decrease PIA.

CORRELATION OF craniovertebral PARAMETERS WITH THE RETROPHARYNGEAL SPACE IN POSTERIOR C1-C2 ARTHRODESIS

ABSTRACT Introduction/Objective: The craniovertebral junction (CVJ) requires a detailed evaluation, as the changes in alignment caused by surgery can affect adjacent structures in a secondary way. Examples of these effects are dyspnea or dysphagia after posterior occipitocervical arthrodesis, due to decreased caliber of the oropharynx. These changes can be identified perioperatively by several radiographic parameters that aim to predict possible postoperative respiratory complications. Such complications appear to be related to the narrowest oropharyngeal airway space (nPAS), and may also occur following atlantoaxial (C1-C2) arthrodesis. This work aims to correlate the variation in CVJ alignment parameters before and after C1-C2 arthrodesis with the variation in nPAS. Methods: Patients who underwent posterior C1-C2 arthrodesis between 2011 and 2019 at the National Institute of Traumatology and Orthopedics (INTO) were included in the study, totaling 26 patients. The parameters evaluated included cervical lordosis, C1-C2 angle, slope of C2, Occipito-C2 angle (O-C2), pharyngeal inlet angle (PIA), pharyngeal tilt angle (PTA), occiput and external acoustic meatus to axis angle (O-EAa), cranial transverse motion against C2 angle (C2TA), axial tilt (AT) and the percentage of change in nPAS (%∆nPAS). Results: A correlation was observed between the change in C1-C2 angle, O-C2, PTA, C2TA and the %∆nPAS. Conclusion: The change in cervical alignment and CVJ parameters is correlated with %∆nPAS and should, therefore, be evaluated before and after atlantoaxial fusion as a means of predicting a possible respiratory complication. Level of Evidence: III; Cross sectional study .

Occipitocervical fusion and dysphagia. The role of head neck alignment: A case report

Dysphagia is a less reported but serious adverse outcome post occipitocervical fusion. Any patient suffering from dysphagia and or nasal regurgitation post fusion in flexion should be offered early revision. The right position for occipitocervical fusion is neutral alignment.

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.

Protecting Against Postoperative Dyspnea and Dysphagia After Occipitocervical Fusion

BACKGROUND

Upper airway obstruction leading to dyspnea and dysphagia after occipitocervical fusion is a rare complication that has significant morbidity.

OBJECTIVE

To estimate the frequency of postoperative dyspnea and dysphagia in children after occipitocervical fusion and to identify variables associated with its occurrence.

METHODS

We retrospectively reviewed outcomes from all pediatric occipitocervical fusions at our institution between 2007 and 2014. Pre- and postoperative computed tomography (CT) scans were compared to determine differences in the clivoaxial (OC2) angles.

RESULTS

Sixty-seven pediatric patients underwent occipitocervical fusions. Median age was 9.6 yr (range 6 mo-18 yr). Fifty-six of 62 patients (90.3%) with at least 1 yr of follow-up had successful fusions. Eleven had pre-existing symptoms or otherwise compromised examination (eg, severe traumatic brain injury). None of 15 patients placed in extension (>2 degrees) relative to preoperative CT in Situ position developed new dyspnea or dysphagia. Nine of forty patients (23%) kept in Situ or flexed position developed new symptoms of dyspnea or dysphagia. Dysphagia in patients fused in the in Situ position was milder and resolved within a few weeks. No patient under age 5 (n = 20) developed symptoms of dyspnea or dysphagia regardless of head position. There were 3 cases of infection, 1 clinically silent vertebral artery injury, and 3 deaths at last follow-up.

CONCLUSION

Positioning of the child's head prior to occipitocervical fusion has considerable impact on outcomes, especially in older children. Careful measurements of the OC2 angle during surgery to ensure optimal head positioning in Situ or slightly extended position may prevent postoperative dysphagia or dyspnea.

A rare case of difficult airway management in a Klippel-Feil syndrome pediatric patient with osseous torticollis undergone orthopedic surgery : Difficult airway in pediatric patient with torticollis

Background

Orthopedic surgery for cervical torticollis poses potential threat to airway management both in tracheal intubation and extubation. Klippel-Feil syndrome (KFS) is a complex syndrome of osseous and visceral anomalies. The anatomical characteristics of KFS might have significant implications for airway management.

Case presentation

This is a rare case of an 8-year-old boy presenting with osseous torticollis, congenital occipito-atlantal deformity, congenital basilar invagination and KFS undergone elective torticollis correction surgery. Though with difficulty, tracheal intubation was successfully performed. Extubation failed twice on postoperative day 2 and 10, and required tracheostomy. Based on radiological findings, we speculated that prolonged airway edema accounted for the main reason of the failed extubation, the hypertrophic tonsil and occipito-cervical fusion resulted in reduced oropharyngeal space and limited cervical range of motion. Moreover, the Chiari malformation and KFS complicated the airway condition and lead to prolonged airway obstruction. The tracheostomy casing was removed 1 month later.

Conclusions

Cautions should be taken in extubation of pediatric patients undergone major osseous torticollis surgery. Reintubation should be prepared in case of failed extubation. Severe post-operative airway edema, complicated with hypertrophic tonsil, the structural abnormalities in the oropharyngeal cavity, and occipito-cervical deformities constituted the decreased oropharyngeal space and resulted in failed extubation. For severe airway compromise and prolonged intubation, tracheostomy should be considered.

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.

Clinical Outcomes of Endoscopic Endonasal Odontoidectomy: A Single-Center Experience

BACKGROUND

Odontoidectomy for basilar invagination and craniovertebral junction pathology traditionally has been performed using a transoral route. However, the endoscopic endonasal approach to the anterior craniovertebral junction may offer safer and more effective access when compared with transoral approaches. The objective of this study is to review the surgical outcomes and complications associated with endoscopic endonasal odontoidectomy.

METHODS

This study is a retrospective chart review of all adult patients who underwent an endoscopic endonasal odontoidectomy at a single tertiary care center between January 2011 and May 2019.

RESULTS

Seventeen patients who underwent endoscopic endonasal odontoidectomy were included. The median age at admission was 67 years (range: 33-84 years) and 65% of the patients were female. One patient (1/17, 6%) had vertebral artery injury, which had to be coiled with no neurologic deficits, and 4 patients (4/17, 24%) had intraoperative CSF leaks with no postoperative leak. Fourteen (14/17, 82%) patients were extubated by postoperative day 1. Three patients (3/17, 18%) developed postoperative sinus infections and required antibiotics. Eight patients (8/17, 47%) developed transient postoperative dysphagia. One patient (1/17, 6%) had postoperative epistaxis and 1 patient (1/17, 6%) had postoperative lower cranial nerve symptoms. The median length of hospital stay was 13 days (range: 2-44 days).

CONCLUSIONS

Although the transoral approach has been the traditional route for anterior decompression of the craniovertebral junction, endoscopic endonasal odontoidectomy is a feasible and well-tolerated procedure associated with satisfactory patient outcomes and low morbidity.

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.

Can Posterior Reduction Replace Odontoidectomy as Treatment for Patients With Congenital Posterior Atlantoaxial Dislocation and Basilar Invagination?

BACKGROUND

For patients with odontoid process protrusion and basilar invagination, posterior screw–rod fixation can usually achieve satisfactory horizontal reduction, but in some cases satisfactory reduction in the vertical direction cannot be achieved at the same time.

OBJECTIVE

To propose a method for calculation of the theoretical maximum vertical reduction possible in individual patients.

METHODS

The computed tomography imaging data of patients with occipitalization and basilar invagination who were treated at our institute between January 2013 and June 2016 were retrospectively analyzed. The direction of odontoid reduction was decided by the inclination of the lateral joint. The atlanto-dental distance was assumed to be the maximum possible reduction in the horizontal direction. The maximum vertical reduction possible was calculated based on these values.

RESULTS

A total of 82 patients (34 males and 48 females) were included. The theoretical vertical reduction value was 4.2 ± 3.0 mm, which was significantly smaller than that of the dental protrusion (14.5 ± 3.8 mm, P = .000). Analysis of follow-up data (29 cases) showed that, the difference between the theoretical vertical reduction value H (4.7 ± 3.5 mm) and the actual vertical reduction value Ha (5.6 ± 3.5 mm) was not significant (P = .139).

CONCLUSION

The theoretical calculation method we proposed can well predict the actual degree of vertical reduction. The theoretical vertical reduction value is significantly lower than the odontoid protrusion value, indicating that satisfactory reduction in the vertical direction is difficult with a posterior approach alone.

Revision for Failed Craniovertebral Junction Stabilization: A Report of 30 Treated Cases

OBJECTIVE

To analyze the probable causes of failed craniovertebral junction stabilization procedures, and to evaluate the advantages of the Goel technique in revision surgery and the positive factors that lead to reduction of the instability and achieve ultimate arthrodesis.

METHODS

During the period from January 2010 to June 2018, we treated 30 cases where previous attempt at craniovertebral stabilization with various fixation techniques had failed and the patients presented with progressively worsening neurologic deficits. All patients were re-operated by lateral mass fixation techniques described by the senior author. The technique involved opening of the atlantoaxial joint, denuding the articular cartilage, introduction of bone graft within the articular cavity, and plate and screw fixation. No bone decompression was done.

RESULTS

Fixation of multiple subaxial spinal segments (n = 9), inclusion of occipital bone in the fixation construct (n = 21), and dependence on metal stabilization rather than bone fusion (n = 19) appear to be important causes of implant failure. All patients improved in clinical symptoms after revision surgery. Postoperative images of all patients demonstrated significant reduction of the atlantoaxial dislocation and craniovertebral junction realignment. During the average follow-up period of 32 months, all reoperated patients continued to show clinical recovery. No further surgery was necessary.

CONCLUSIONS

Although relatively difficult, when indicated, reoperation and direct stabilization of the atlantoaxial joint can result in significant and enduring clinical recovery.

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°.

Influence of Postoperative O-C2 Angle on the Development of Dysphagia After Occipitocervical Fusion Surgery: Results from a Retrospective Analysis and Prospective Validation

BACKGROUND

Postoperative dysphagia is a known complication of anterior cervical surgery, but its incidence and possible mechanisms are seldom reported after occipitocervical fusion (OCF). Our objective was to study the relationship between craniocervical alignment and the development of dysphagia after OCF for the treatment of basilar invagination with atlantoaxial instability.

METHODS

The study consisted of a retrospective series and a prospective series. Seventy-eight patients who underwent OCF (30 male, 48 female) were reviewed in the retrospective series. The presence and duration of postoperative dysphagia were recorded with an in-person questionnaire or telephone interview. Sagittal reconstructed computed tomography images before and after the procedure were collected. The O-C2 angle and C2-C7 angle were measured. The relationship of these parameters and their influence to the incidence of dysphagia were analyzed. The patients were grouped according to whether they developed postoperative dysphagia (group A) or not (group B). A prospective case series of 27 patients (group C) were reported to verify the influence of O-C2 angle on postoperative dysphagia.

RESULTS

In the retrospective case series, 19 patients (24.4%) complained of postoperative dysphagia after OCF. The change in the O-C2 angle was significantly lower in group A than in group B (P < 0.001). In the prospective case series, only 1 patient (3.7%) complained of postoperative dysphagia.

CONCLUSIONS

O-C2 angle plays an important role in the development of postoperative dysphagia after OCF procedure. Careful intraoperative alignment of the O-C2 angle may help to reduce the incidence and severity of postoperative dysphagia after OCF.

Radiographic Outcomes of Upper Cervical Fusion for Pediatric Patients Younger Than 10 Years

Purpose: This study aimed to investigate radiographic outcomes after posterior spinal fusion (PSF) for pediatric patients younger than 10 years with upper cervical disorders. Methods: Thirteen patients (mean age at surgery, 5.9 years; range, 1 to 9 years) who underwent PSF with a minimum of 2 years of follow-up (mean, 5.8 years) were included. Diagnoses were atlanto-axial instability due to congenital disorders for 11 patients and atlanto-axial rotatory fixation for 2 patients. The fusion area was occipito-cervical for 7 patients and C1/2 for 6 patients. PSF was performed using rigid screw-rod constructs for 6 patients and conventional techniques for 7 patients. Ten patients required halo immobilization after surgery. Fusion status, perioperative complications, radiographic alignment, and range of motion (ROM) from C2 to C7 were evaluated. Results: Twelve patients successfully achieved bony fusion (fusion rate, 92%), but complications occurred in 5 patients. Regarding radiographic measures (preoperative/postoperative/final follow-up), the mean atlanto-dental interval was significantly reduced (8.0 mm/2.7 mm/3.5 mm) and the C2-7 ROM was increased (from 49.4 degrees to 66.0 degrees) at the final follow-up (both comparisons, p<0.05). Sagittal alignment was unchanged. Conclusion: Use of rigid screw-rod instrumentation in the upper cervical spine with careful radiological evaluation is amenable for pediatric patients younger than 10 years. However, conventional procedures such as wiring fixation with rigid external immobilization are still alternative options for preventing serious neurological and vascular complications.

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.

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.

Periosteal turndown flap for posterior occipitocervical fusion: a technique review

PURPOSE

Recently, several authors have proposed techniques for improving the fusion rate in pediatric posterior occipitocervical fusion including a variety of implants and the use of bone morphogenetic protein. A technique by Koop et al. using a periosteal flap for occipitocervical arthrodesis was described in 1984.

METHODS

A straight incision is made about the posterior neck to expose the occipitocervical region from the inion superiorly to the lowest cervical vertebrae to be fused inferiorly. The occiput is exposed superficial to the periosteum, which is then reflected and elevated from the occiput. The attachment is preserved at the caudal base of the flap and reflected over the intended area of fusion. When possible, fixation is then performed with cables, wires, screws, hooks, or plates.

CASE EXAMPLE

A 6-year-old male with an occiput to C2 distraction injury underwent posterior spinal fusion from occiput to C3 using sublaminar wires, periosteal turndown flap, and autologous iliac crest bone graft.

CONCLUSION

In small children with traumatic upper cervical spine instability, the periosteal turndown technique may be used as a safe adjunct for occipitocervical fusions.

Patient-reported outcomes of occipitocervical and atlantoaxial fusions in children

OBJECTIVE There is limited literature on patient-reported outcomes (PROs) and health-related quality of life (HRQOL) outcomes in pediatric patients undergoing surgery for craniovertebral junction pathology. The aim of the present study was to assess surgical and quality of life outcomes in children who had undergone occipitocervical or atlantoaxial fusion. METHODS The authors retrospectively reviewed the demographics, procedural data, and outcomes of 77 consecutive pediatric patients who underwent posterior occipitocervical or atlantoaxial fusion between 2008 and 2015 at Texas Children's Hospital. Outcome measures (collected at last follow-up) included mortality, neurological improvement, complications, Scoliosis Research Society Outcomes Measure-22 (SRS-22) score, SF-36 score, Neck Disability Index (NDI), and Pediatric Quality of Life Inventory (PedsQL). Multivariate linear regression analysis was performed to identify factors affecting PROs and HRQOL scores at follow-up. RESULTS The average age in this series was 10.6 ± 4.5 years. The median follow-up was 13.9 months (range 0.5-121.5 months). Sixty-three patients (81.8%) were treated with occipitocervical fusion, and 14 patients (18.1%) were treated with atlantoaxial fusion. The American Spinal Injury Association (ASIA) grade at discharge was unchanged in 73 patients (94.8%). The average PRO metrics at the time of last follow-up were as follows: SRS-22 score, 4.2 ± 0.8; NDI, 3.0 ± 2.6; the parent's PedsQL (ParentPedsQL) score, 69.6 ± 22.7, and child's PedsQL score, 75.5 ± 18.7. Multivariate linear regression analysis revealed that older age at surgery was significantly associated with lower SRS-22 scores at follow-up (B = -0.06, p = 0.03), and the presence of comorbidities was associated with poorer ParentPedsQL scores at follow-up (B = -19.68, p = 0.03). CONCLUSIONS This study indicates that occipitocervical and atlantoaxial fusions in children preserve neurological function and are associated with acceptable PROs and ParentPedsQL scores, considering the serious nature and potential for morbidity in this patient population. However, longer follow-up and disease-specific scales are necessary to fully elucidate the impact of occipitocervical and atlantoaxial fusions on children.