Changes in Swallowing After Anterior Cervical Discectomy and Fusion With Instrumentation: A Presurgical Versus Postsurgical Videofluoroscopic Comparison

Ultrasonographic Evaluation of Upper Esophageal Sphincter for Dysphagia During the Acute Postoperative Phase of Anterior Cervical Surgery

STUDY DESIGN

A retrospective study.

OBJECTIVE

To verify the pathophysiology of dysphagia during the acute postoperative phase of anterior cervical surgery and to identify its predictive features, using ultrasonographic (US) examination for upper esophageal sphincter (UES).

SUMMARY OF BACKGROUND DATA

There are no clinical studies investigating dysphagia after anterior cervical surgery, using US examination for UES.

MATERIALS AND METHODS

We enrolled patients who underwent anterior cervical spine surgery between August 2018 and March 2022. Dysphagia was evaluated using the Eating Assessment Tool-10 (EAT-10) questionnaires. The US examination was performed preoperatively and 2 weeks postoperatively. Three US parameters for morphologic measurements (outer diameter, inner diameter, and muscle thickness) and 4 for functional measurements (displacement, time to relax, passing duration, and time to contract) were assessed. To verify the pathophysiology of postoperative dysphagia, we examined the change in the ratios of US parameters (=US parameter 2 weeks postoperatively /US parameter at baseline ) and the existence of significant correlations with change in the EAT-10 score (=EAT-10 2 weeks postoperatively -EAT-10 at baseline ). To identify the predictive features, the baseline US parameters were compared between dysphagia (+) and dysphagia (-) groups.

RESULTS

A total of 46 patients (mean age, 61.3 y; 78.3% male) were included for analysis. A greater increase of the EAT-10 score after surgery was positively correlated with change ratios of the muscle thickness and time to contract and negatively with change ratio of the inner diameter. The dysphagia (+) group exhibited significantly greater inner diameter and smaller muscle thickness at baseline than the dysphagia (-) group.

CONCLUSION

Dysphagia during the acute postoperative phase of anterior cervical surgery is caused by the physical narrowing of the inner lumen due to muscle thickening of the UES and sphincter contractile dysfunction. In addition, a baseline UES morphology characterized by a greater inner diameter and a thinner muscle layer is predictive of postoperative dysphagia.

Radiographic Magnification on Videofluoroscopy: An Important Variable to Consider for Scaled Analyses of Swallowing

PURPOSE

Traditionally, kinematic measures on videofluoroscopy require the use of an external scalar (such as a penny) to transform pixels to absolute distances. Videofluoroscopy is subject to image magnification based on the distance of the feature of interest to the X-ray source. However, the impact of the position/location of the external scalar on swallowing measures is unknown. Our goal was to systematically investigate the accuracy of various common external scalar locations in lateral and anterior-posterior (A-P) view.

METHOD

U.S. pennies were taped to a styrofoam head in three positions (on the left and right lateral neck and in midline submentally). Locations were measured to ensure equal left and right, as well as midline, placement. A metal screwdriver (6 mm in diameter) was inserted into the premanufactured hole that is centrally located at the bottom of the styrofoam head. The head was centered on a medical tray and placed in the middle of a Siemens Alpha C-arm Fluoroscope field. ImageJ was used to measure penny length in pixels (three locations) in both lateral and A-P views. Penny length was known (19.05 mm), and, therefore, used to derive screwdriver size (for each location) for comparison to the actual screwdriver size.

RESULTS

All scalars overestimated the screwdriver size ranging from 6.55 to 7.87 mm, representing a 9%-31% inflation. Scalars closer to the X-ray source had the largest magnification.

CONCLUSIONS

Our results confirm that image magnification of external scalars is a significant source of variability that is currently unaccounted for in the swallowing literature. Recommendations for future research design/measurement methods are provided.

Kinematic analysis of chewing and swallowing function after cervical spine surgery

PURPOSE

Although movement of the hyoid bone is different for masticatory swallowing and liquid swallowing in normal subjects, it has not been studied after cervical spine surgery. Therefore, we analyzed the swallowing dynamics of masticatory swallowing in anterior cervical spine disease surgery using foods that require chewing close to actual meals.

METHODS

A day before and one week after the surgery, a videofluoroscopic swallow study (VFSS) was performed, and the distance of hyoid bone movement in the anterior and superior directions, amount of opening of the upper esophageal sphincter (UES), time of passage through the pharynx, number of swallows, and amount of pharyngeal residual were measured on the VFSS images during a masticatory swallow of corn flakes. The swallowing function was evaluated by DSS (dysphagia severity scale) and FOIS (functional oral intake scale). Imaging software was used for the measurements.

RESULTS

Postoperative hyoid movement during masticatory swallowing was not significantly different for anterior movement but significantly limited in upward movement (p = 0.002); UES opening volume was significantly decreased (p < 0.001), and bolus residue was significantly worse (p < 0.001), compared to preoperative. The pharyngeal transit time was not significantly different; the number of swallows increased (p < 0.001), along with DSS (p < 0.001) and FOIS (p < 0.001), with significant differences before and after surgery, indicating worsened swallowing function.

CONCLUSIONS

Swallowing function worsened in masticatory swallowing after surgery for cervical spine disease, mainly due to the restriction of upward movement of the hyoid bone and the resulting increase in pharyngeal residuals after swallowing.

Alterations in Swallowing Six Weeks After Primary Anterior Cervical Discectomy and Fusion (ACDF)

This aim of this study is to characterize the nature and pathophysiology of dysphagia after ACDF surgery by precisely and comprehensively capturing within-subject changes on videofluoroscopy between preoperative and postoperative time points. 21 adults undergoing planned primary ACDF procedures were prospectively recruited and enrolled. Participants underwent standardized preoperative and six-week postoperative videofluoroscopic swallow studies. Videos were blindly rated using the Penetration-Aspiration Scale (PAS) and analysis of total pharyngeal residue (%C2-42), swallowing timing, kinematics, and anatomic change was completed. Linear mixed-effects modeling was used to explore the relationships between possible predictor variables and functional outcomes of interest that changed across timepoints. There was no change in PAS scores across timepoints. Total pharyngeal residue (%C2-C42) was increased postoperatively (p < 0.001). Our statistical model revealed significant main effects for timepoint (p = 0.002), maximum pharyngeal constriction area (MPCAN) (p < 0.001), and maximum thickness of posterior pharyngeal (PPWTMAX) (p = 0.004) on the expression of total pharyngeal residue. There were significant two-way interactions for timepoint and MPCAN (p = 0.028), timepoint and PPWTMAX (p = 0.005), and MPCAN and PPWTMAX (p = 0.010). Unsurprisingly, we found a significant three-way interaction between these three predictors (p = 0.027). Our findings suggest that in planned ACDF procedures without known complications, swallowing efficiency is more likely to be impaired than airway protection six weeks after surgery. The manifestation of impaired swallowing efficiency at this timepoint appears to be driven by a complex relationship between reduced pharyngeal constriction and increased prevertebral edema.

Symptoms and coping of patients with dysphagia after anterior cervical spine surgery: a qualitative study

AIM

To explore the subjective symptoms, psychological characteristics and coping strategies of patients with dysphagia after anterior cervical spine surgery, so as to provide the basis for formulating strategies to help patients with dysphagia solve clinical practice problems and to improve their quality of life after surgery.

METHODS

Using the phenomenological research method and the purpose sampling method, semi-structured interviews were conducted with 22 participants with dysphagia at 3-time points after anterior cervical spine surgery (7 days, 6 weeks, and 6 months).

RESULTS

A total of 22 (10 females and 12 males) patients, with years old ranging between 33 and 78 years were interviewed. When analysing the data, the following 3 categories were extracted from the participant interviews: "Subjective symptoms, Coping style and impact on social life". The 3 categories consist of 10 sub-categories.

CONCLUSIONS

The results showed that swallowing-related symptoms may occur after anterior cervical spine surgery. Many patients had developed compensatory strategies to manage or reduce the burden of these symptoms, but lacked professional guidance from health care professionals. Moreover, dysphagia after neck surgery has its unique characteristics, involving the interaction of physical, emotional and social factors, which requires early screening.Healthcare professionals should provide better psychological support in the early or late postoperative period to ensure the improvement of health outcomes and patients' quality of life.

Association between Anterior Surgical Approach and Dysphagia Severity in Patients with Cervical Spinal Cord Injury

INTRODUCTION

Early detection and management of dysphagia are essential for preventing aspiration pneumonia and reducing mortality in patients with cervical spinal cord injury (C-SCI). In this study, we identified risk factors for dysphagia in patients with C-SCI by analyzing the correlation between the clinical factors and the severity of dysphagia, not the presence or absence of dysphagia. Combined with the analysis results of previous studies, we thought that this additional analysis method could more accurately reveal the risk factors for dysphagia in patients with C-SCI.

METHODS

The presence and severity of dysphagia in patients with C-SCI was evaluated using a modified videofluoroscopic dysphagia scale (mVDS) and penetration-aspiration scale (PAS). All included patients with C-SCI performed a video fluoroscopic swallowing study (VFSS). Clinical factors such as age, sex, the presence of tracheostomy, spinal cord independence measure (SCIM), pulmonary function test (PFT), including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FVC/FEV1, maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP), American Spinal Cord Injury Association (ASIA) score, Berg Balance Scale (BBS), and operation method were investigated.

RESULTS

In the multivariate regression analysis, the anterior surgical approach was the only clinical factor that had a significant correlation in both mVDS and PAS, which represents the severity of dysphagia in C-SCI patients (p < 0.05).

CONCLUSION

The anterior surgical approach was correlated with the severity of dysphagia in patients with C-SCI. Considering this, as one of the risk factors affecting dysphagia in patients with C-SCI, surgical method may also need to be considered. Additionally, we recommend that clinicians should pay particular attention to the potential for development of dysphagia in patients who received anterior cervical surgery. However, further prospective studies with larger sample sizes are needed for more accurate generalization.

Using Reference Values to Identify Profiles of Swallowing Impairment in a Case Series of Individuals With Traumatic Spinal Cord Injury

PURPOSE

In this article, we illustrate use of a systematic approach to rating videofluoroscopic swallowing studies (VFSS), the Analysis of Swallowing Physiology: Events, Kinematics and Timing (ASPEKT) method. The method is applied to a clinical case series of individuals with a history of traumatic spinal cord injury (tSCI) requiring surgical intervention using a posterior approach. Previous studies suggest that swallowing is highly variable in this population given heterogeneity in mechanisms, location and extent of injury, and in surgical management approaches.

METHOD

The case series involved 6 individuals who were at least 1 month postsurgery for management of tSCI. Participants completed a VFSS using a standardized bolus protocol. Each VFSS was blindly rated in duplicate using the ASPEKT method and compared with published reference values.

RESULTS

The analysis revealed considerable heterogeneity across this clinical sample. Penetration-aspiration scale scores of 3 or higher were not observed in this cohort. Of note, patterns of impairment did emerge, suggesting there are some commonalities across profiles in this population, including the presence of residue associated with poor pharyngeal constriction, reduced upper esophageal opening diameter, and short upper esophageal sphincter opening duration.

CONCLUSIONS

Although the participants in this clinical sample shared a history of tSCI requiring surgical intervention using a posterior approach, there was great heterogeneity in swallowing profile. Using a systematic method to identify atypical swallowing parameters can guide clinical decision making for determining rehabilitative targets and measuring swallowing outcomes.

A scoping review of the methods used to capture dysphagia after anterior cervical discectomy and fusion: the need for a paradigm shift

OBJECTIVE

Dysphagia is the most commonly reported complication of annterior cervical discectomy and fusion (ACDF) surgery. However, the incidence of dysphagia post-ACDF varies widely-partly attributable to differing outcome measures used to capture dysphagia. Our objective was to conduct a scoping review of the literature to quantify which dysphagia outcome measures have been employed post-ACDF and examine trends by study design, year, and location.

METHODS

After removing duplicates, 2396 abstracts were screened for inclusion. A total of 480 studies were eligible for full-text review. After applying exclusion criteria, data was extracted from 280 studies. We extracted the dysphagia outcome measure(s), study design (prospective vs retrospective), year, and location (country). Approximately 10% of studies were repeated for intra-rater agreement.

RESULTS

In total, 317 dysphagia outcome measures were reported in 280 studies (primarily retrospective-63%). The largest proportion of outcome measures were categorized as "unvalidated patient-reported outcome measures" (46%), largely driven by use of the popular Bazaz scale. The next most common categories were "insufficient detail" and "validated patient-reported outcome measures" (both 16%) followed by "chart review/database" (13%) and instrumental assessment (7%). Studies examining dysphagia post-ACDF steadily increased over the years and the use of validated measures increased in the past 10 years.

CONCLUSIONS

This scoping review of the literature highlights that nearly half of the ACDF dysphagia literature relies on unvalidated patient-reported outcome measures. The current understanding of the mechanism, timeline, and presentation of dysphagia post-ACDF are likely limited due to the metrics that are most commonly reported in the literature.

Swallowing rehabilitation following spinal injury: A case series

Context/objective: Swallowing difficulties (dysphagia) are well recognized after spinal injury. There are no published rehabilitation efficacy studies to date. This study explored viability and outcomes of swallowing rehabilitation programs for four patients with persisting dysphagia.Design: Prospective, quantitative experimental longitudinal case series.Setting: Spinal rehabilitation unit or patients' homes.Interventions: Four patients engaged in a 6-week (3×weekly) individualized progressive rehabilitation program.Outcome measures: Objective videofluoroscopic measures of timing and displacement and a validated self-reported questionnaire - the Eating Assessment Tool (EAT-10) were taken pre-therapy, immediately post-therapy and EAT-10 was repeated at 3 months. Feeling and fatigue scale scores were taken before and after each therapy session.Results: Patients (63, 67 yr, 67 yr, 76 yr; 3 male) had varying spinal diagnoses (2 traumatic, all involving the C-spine) and length of dysphagia (6 weeks, 6 weeks, 12 weeks, 10 yr). Common physiological impairments across all patients were: reduced maximum hyoid displacement, reduced pharyngeal constriction and reduced pharyngoesophageal segment maximum opening. Therapy programs were well received with 100% compliance. Participants made quantitative improvements in their videofluoroscopic measures of timing and displacement. Three out of four participants were able to have their percutaneous endoscopic gastrostomies (PEG) removed. EAT-10 scores significantly improved for all patients (P < .001). Poor upper limb function and restricted neck flexion prohibited some exercises.Conclusions: For many patients following spinal injury, dysphagia resolves during the acute phase of post-surgery recovery. For some, significant pharyngeal impairments persist. This case series demonstrates potential to regain functional swallowing following a 6-week tailored rehabilitation program. High-quality research exploring efficacy of rehabilitation programs are warranted.

Characterization of dysphagia following anterior cervical spine surgery

BACKGROUND

Post-operative dysphagia is one of the most common complications of anterior cervical spine surgery (ACSS).

OBJECTIVE

Examine post-operative structural and physiologic swallowing changes in patients with dysphagia following ACSS as compared with healthy age and gender matched controls.

METHODS

Videofluoroscopic swallow studies of adults with dysphagia after ACSS were retrospectively reviewed. Seventy-five patients were divided into early (≤2 months) and late (> 2 months) post-surgical groups. Modified Barium Swallow Impairment Profile (MBSImP), Penetration-Aspiration Scale (PAS) scores, and pharyngeal wall thickness (PWT) metrics were compared.

RESULTS

Significant differences were identified for all parameters between the control and early post-operative group. MBSImP Pharyngeal Total (PT) scores were greater in the early group (Interquartile Range (IQR) = 9-14, median = 12) versus controls (4-7, 5, P < 0.001) and late group (0.75-7.25, 2, P < 0.001). The early group had significantly higher maximum PAS scores (IQR = 3-8, median = 7) than both the control group (1-2, 1, P < 0.001) and late post-operative group (1-1.25, 1, P < 0.001). PWT was significantly greater in the early (IQR = 11.12-17.33 mm, median = 14.32 mm) and late groups (5.31-13.01, 9.15 mm) than controls (3.81-5.41, 4.68 mm, P < 0.001).

CONCLUSION

Dysphagic complaints can persist more than two months following ACSS, but often do not correlate with validated physiologic swallowing dysfunction on VFSS. Future studies should focus on applications of newer technology to elucidate relevant deficits.

Characterizing dysphagia after spinal surgery

Context/Objective: Dysphagia after spinal surgery is well recognised. Characteristics of post-operative dysphagia are not well defined. This study explored severity, longevity, and physiological characteristics of dysphagia.Design: Prospective, observational study.Setting: Tertiary urban hospital.Participants: Two-hundred fifty patients consecutively receiving spinal surgery.Interventions: Demographic and clinical information were collected. Flexible endoscopic evaluation of swallowing (FEES) and videofluoroscopic study of swallowing (VFSS) recordings were analyzed.Outcomes Measures: FEES recordings were analyzed using three validated symptom scales. VFSS recordings were analyzed using 10 objective digital measures of timing, displacement and symptoms.Results: Of 250 patients, 75 were referred for swallowing assessment. Sixty-two received FEES and 11 VFSS. Patients with anterior approach surgery for cervical level injuries represented 85% of referrals (n = 64). Secretion accumulation, aspiration and residue scores decreased significantly within 2 months for most patients. For those with persisting dysphagia, objective VFSS measures demonstrated significant impairments in pharyngeal constriction, hyoid displacement and pharyngoesophageal segment opening with corresponding residue and aspiration scores. By 6 months, all patients had returned to a regular diet except three patients following anterior cervical discectomy and fusion (ACDF) who remained nil by mouth with severe physiological impairments.Conclusions: A quarter of patients following spinal surgery present with dysphagia. For most, symptoms decrease significantly by 2 months and patients return to normal diets. Early screening of dysphagia is critical to avoid secondary complications and prolonged hospitalizations. For some, significant pharyngeal impairments persist and high-quality case series exploring efficacy of rehabilitation programmes are needed.

Comparison of Bazaz scale, Dysphagia Short Questionnaire, and Hospital for Special Surgery-Dysphagia and Dysphonia Inventory for Assessing Dysphagia Symptoms After Anterior Cervical Spine Surgery in Chinese Population

Dysphagia is one of the most common complaints after anterior cervical spine surgery. The Bazaz scale, the Dysphagia Short Questionnaire (DSQ), and the Hospital for Special Surgery-Dysphagia and Dysphonia Inventory (HSS-DDI) were patient-reported outcome measures assessing the patients' perceptions of their swallowing functions after surgery. This prospective diagnostic test study aimed to compare these surveys' psychometric properties in the Chinese population. We evaluated 150 consecutive patients after anterior cervical spine surgery with the Bazaz scale, DSQ, HSS-DDI, and M.D. Anderson Dysphagia Inventory (MDADI). The reliability and validity of the Bazaz scale, DSQ, and HSS-DDI were compared. Receiver operating characteristic (ROC) curves of the DSQ, Bazaz scale, and HSS-DDI were constructed using the MDADI as a reference criterion. Their areas under the curve (AUCs) were further analyzed. In total, 132 participants completed all of the surveys. The results showed that all surveys were significantly correlated with each other. The HSS-DDI and HSS-Dysphagia subscale showed near-perfect reliability (Cronbach α = 0.969 and 0.957, respectively). ROC curves showed both HSS-DDI and HSS-Dysphagia subscale had greater accuracy (AUCs > 0.9) in detecting mild dysphagia and moderate/severe dysphagia. The HSS-Dysphagia subscale achieved higher accuracy in assessing the dysphagia symptoms after anterior cervical spine surgery. The Bazaz scale was considered less accurate than other scales. Our results provided guidance for selecting the appropriate measuring tool during clinical and research practices.

Fluoroscopic Swallowing Abnormalities in Dysphagic Patients Following Anterior Cervical Spine Surgery

Objectives:

To evaluate the precise objective fluoroscopic abnormalities in persons with dysphagia following anterior cervical spine surgery (ACSS).

Methods:

129 patients with dysphagia after ACSS were age and sex matched to 129 healthy controls. All individuals underwent videofluoroscopic swallow study (VFSS). VFSS parameters abstracted included upper esophageal sphincter (UES) opening, penetration aspiration scale (PAS), and pharyngeal constriction ratio (PCR). Other data collected included patient-reported outcome measures of voice and swallowing, number of levels fused, type of plate, vocal fold immobility, time from surgery to VFSS, and revision surgery status.

Results:

The mean age of the entire cohort was 63 (SD ± 11) years. The mean number of levels fused was 2.2 (±0.9). 11.6% (15/129) were revision surgeries. The mean time from ACSS to VFSS was 58.3 months (±63.2). The majority of patients (72.9%) had anterior cervical discectomy and fusion (ACDF). For persons with dysphagia after ACSS, 7.8% (10/129) had endoscopic evidence of vocal fold immobility. The mean UES opening was 0.84 (±0.23) cm for patients after ACSS and 0.86 (±0.22) cm for controls ( P > .0125). Mean PCR was 0.12 (±0.12) for persons after ACSS and 0.08 (±0.08) for controls, indicating significant post-surgical pharyngeal weakness ( P < .0125). The median PAS was 1 (IQR 1) for persons after ACSS as well as for controls. For ACSS patients, PCR had a weak correlation with EAT-10 ( P < .0125).

Conclusion:

Chronic swallowing dysfunction after ACSS appears to be secondary to pharyngeal weakness and not diminished UES opening, the presence of aspiration, vocal fold immobility, or ACSS instrumentation factors. Level of Evidence: 3b

Use of the Penetration-Aspiration Scale in Dysphagia Research: A Systematic Review

The penetration-aspiration scale (PAS) is an 8-point scale used to characterize the depth and response to airway invasion during videofluoroscopy. Though widely used in the field of deglutition, there is a lack of consensus regarding the statistical properties of the scale. In order to better understand the state of the literature and the statistical use of the PAS, a systematic review was undertaken to descriptively examine trends in statistical and reporting practices of the PAS since its inception. Online databases were searched for studies citing the original PAS article, which yielded 754 unique articles. Of these, 183 studies were included in the review. Results showed inconsistencies in the statistical use of the scale; 79 studies treated the PAS as ordinal, 71 as categorical, and 49 as interval. Ten types of categorizations were identified. Reporting of power analyses (9%), as well as inter- (26%) and intra-rater (17%) reliability, was uncommon. Among studies that administered multiple bolus volumes or consistencies, 55% reported PAS analyses at the participant/group level only. This review confirms the existence of discrepancies in the statistical treatment of the PAS. A lack of consensus among researchers limits comparisons between studies. The approach to handling this scale dictates the statistical tests used, potentially affecting results and interpretations. Consistent application of statistically sound approaches to PAS analyses is vital for the future of deglutition research.

Differences in swallow physiology in patients with left and right hemispheric strokes

BACKGROUND

We sought to determine the impact of lesion lateralization and lesion volume on swallow impairment on group-level by comparing patients with left and right hemisphere strokes and on patient-level by analyzing patients individually.

METHODS

We performed a retrospective, observational, cross-sectional study of 46 patients with unilateral (22 left, 24 right), acute, first-ever, ischemic strokes who received a diffusion weighted MRI (DW-MRI) and modified barium swallow study (MBSS) during their acute hospital stay. We determined lesion side on the DW-MRI and measured swallow physiology using the Modified Barium Swallow Impairment Profile (MBSImP™©), Penetration-Aspiration Scale (PAS), swallow timing, distance, area, and speed measures. We performed Pearson's Chi-Square and Wilcoxon Rank-Sum tests to compare patients with left and right hemisphere strokes, and Pearson or Spearman correlation, simple logistic regression, linear, and logistic multivariable regression modeling to assess the relationship between variables.

RESULTS

At the group-level, there were no differences in MBSImP oral swallow impairment scores between patients with left and right hemisphere stroke. In adjusted analyses, patients with right hemisphere strokes showed significantly worse MBSImP pharyngeal total scores (p = 0.02), worse MBSImP component specific scores for laryngeal vestibular closure (Bonferroni adjusted alpha p ≤ 0.0029), and worse PAS scores (p = 0.03). Patients with right hemisphere strokes showed worse timing, distance, area, and speed measures. Lesion volume was significantly associated with MBSImP pharyngeal residue (p = 0.03) and pharyngeal total scores (p = 0.04). At the patient-level, 24% of patients (4 left, 7 right) showed opposite patterns of MBSImP oral and pharyngeal swallow impairment than seen at group-level.

CONCLUSION

Our study showed differences in swallow physiology between patients with right and left unilateral strokes with patients with right hemisphere strokes showing worse pharyngeal impairment. Lesion lateralization seems to be a valuable marker for the severity of swallowing impairment at the group-level but less informative at the patient-level.