After Anterior Cervical Discectomy And Fusion Research Articles

87. Development of a machine learning algorithm for neck motion classification in patients after anterior cervical discectomy and fusion (ACDF)

<h3>BACKGROUND CONTEXT</h3> Loss of cervical range of motion (ROM) is a common complication after anterior cervical discectomy and fusion (ACDF). Recovery of cervical ROM is a goal for postoperative ACDF patients and is achieved through prescribed at-home neck exercises and physical therapy. Currently, cervical ROM is assessed periodically via physical examination by trained health care professionals. These methods, however, are incapable of continuous measurement of neck motion in a patient's naturalist environment. A skin-mounted, wireless, and wearable sensor that offers a noninvasive way to continuously monitor neck motion as well as heart rate, respiratory rate, energy expenditure, swallow count, and body orientation would hold significant clinical utility by tracking recovery, ensuring adherence to physical therapy, and providing warning of potentially deleterious excessive motion during the essential postoperative period. <h3>PURPOSE</h3> Develop and validate in healthy normal subjects a machine learning algorithm to classify 8 neck motions: right rotation, left rotation, right lateral bending, left lateral bending, flexion, extension, retraction, protraction Validate the algorithm in postoperative ACDF patients Evaluate clinician and patient usability of the sensor. <h3>METHODS</h3> On 11 healthy subjects (6 females, 5 males), the sensor was placed at the suprasternal notch, centered between the sternocleidomastoid tendons. Ten four-second samples of each of the 8 motions were collected from each subject (880 total neck motion samples). Each sample consisted of the output from the sensor's 3-axis accelerometer and gyroscope: x, y, and z linear accelerations and angular velocities. A convolutional neural network (CNN) model was developed using Python to perform 8-way classification using a step-wise classification scheme. A leave-one-out training/testing scheme was used in which a model was trained on 10 subjects and then tested on the remaining subject, which was iterated across all 11 subjects. Additionally, a random mixing training/testing scheme was used, which involved random mixing of all 880 samples, training on 80% of the mixed samples, and testing on the remaining 20%. Ongoing activities include direct measurement of neck motion in the ACDF population. <h3>RESULTS</h3> Each motion produced a characteristic pattern of linear accelerations and angular velocities, which provided the features that were used for classification. The leave-one-out training/testing scheme yielded a mean accuracy of 84% (+/-12%), ranging from 57 to 94%. Ten trials of the random mixing training/testing scheme yielded a mean accuracy of 91% (+/- 1.0%). Flexion vs retraction and extension vs protraction were the most difficult signals to distinguish. <h3>CONCLUSIONS</h3> Rotation, lateral bending, flexion, extension, retraction, and protraction produce unique motion patterns that can be measured with a wearable sensor containing a 3-axis accelerometer and gyroscope placed at the suprasternal notch. Rotation, lateral bending, flexion, and extension produced the most unique motion signatures. Linear accelerations and angular velocities, measured by accelerometer and gyroscope, respectively, can be strategically selected to perform a step-wise 8-way classification of these neck motions with relatively high accuracy. Validation of the algorithm in the surgical patient population, which is ongoing, could demonstrate the utility of wearable sensors in the ACDF patient population and significantly improve their quality of postoperative care. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P67. Does a high postoperative opioid dose predict chronic use after ACDF?

<h3>BACKGROUND CONTEXT</h3> Currently there is an incomplete understanding of the patient level risk factors for chronic opioid use after anterior cervical discectomy and fusion (ACDF). Postoperative opioid prescriptions in spine surgery have been found to commonly exceed the dose necessary for return to function and pain relief, however the direct relationship between postsurgical opioid dose and chronic opioid abuse has yet to be explored. <h3>PURPOSE</h3> To determine if increased postoperative prescription opioid dosing is an isolated predictor of chronic opioid use after ACDF. <h3>STUDY DESIGN/SETTING</h3> Retrospective Cohort Analysis. <h3>PATIENT SAMPLE</h3> All patients over age 18 who underwent one- to four-level primary or revision ACDF for cervical spondylosis associated with radiculopathy and/or myelopathy at an academic center between 2016- 2019 were retrospectively identified. Patients lacking descriptive data or opioid utilization records or who had surgery performed for trauma, infection, or malignancy were excluded. <h3>OUTCOME MEASURES</h3> Postoperative opioid use prescription metrics: mean morphine equivalent (MME) opioid dose, duration of usage, and the number of prescriptions and pharmacies utilized. Preoperative opioid and benzodiazepine tolerance. Chronicity of postoperative opioid use. <h3>METHODS</h3> Pre- and postsurgical opioid and benzodiazepine prescriptions, including the postoperative peak MME and duration of use, were obtained from the Pennsylvania Prescription Drug Monitoring Program (PDMP). Univariate analysis compared patient demographics and surgical factors across two binary groups of high vs low postoperative opioid dose (high: MME≥ 90, low: MME< 90) and chronic vs short-term opioid use (chronic: ≥120 days or >10 prescriptions). The relationship between chronic opioid use and patterns of immediate postoperative opioid use was evaluated. Binary logistic regressions were created to identify patient specific predictors of high opioid dose and chronic use. <h3>RESULTS</h3> A total of 385 patients met the inclusion criteria. Preoperative opioid tolerance and history of tobacco use were found to be associated with both high postoperative opioid dose and chronic postoperative usage. In addition, younger age correlated with receiving high dose prescriptions and obesity and preoperative benzodiazepine use were associated with chronic opioid use patterns. Chronicity of postoperative opioid use correlated meaningfully with immediate postoperative opioid use metrics including high single prescription dose, change in opioid prescribed, private pay scripatients, and greater than one prescriber and pharmacy. High postoperative opioid dose and preoperative opioid tolerance were identified as isolated predictors of chronic postsurgical opioid use on logistic regression. Regression also determined younger age, increased medical comorbidities, and opioid tolerance were significant predictors for high MME prescriptions. <h3>CONCLUSIONS</h3> High postoperative opioid dose was found to be a significant predictor of chronic opioid use after ACDF regardless of preoperative opioid tolerance. Because a multitude of factors increase patient opioid dose requirements after surgery, further research is required to determine if there exists a causal relationship between high postoperative opioid dosing and chronicity of use. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P66. The impact of anxiety/depression on outcomes following 1-2 level anterior cervical surgery

<h3>BACKGROUND CONTEXT</h3> Outcomes after anterior cervical discectomy and fusion (ACDF) and cervical disc replacement (CDR) are likely impacted by the mental state of a patient during recovery. Psychologic factors such as anxiety/depression might negatively impact outcomes for a subset of patients. <h3>PURPOSE</h3> To elucidate whether anxiety/depression affect outcomes following 1-2 level anterior cervical surgery (ACDF or CDR) at short-term and final follow-up. <h3>STUDY DESIGN/SETTING</h3> Retrospective review of prospectively collected data. <h3>PATIENT SAMPLE</h3> Patients who underwent 1-2 level ACDF/CDR for cervical radiculopathy/myelopathy and had health related quality of life scores (HRQOLs) at 6 weeks, 3 months and 6 months out from surgery. <h3>OUTCOME MEASURES</h3> Patient-reported outcome measures (PROMs) - Neck disability index (NDI), short-form 12 physical component score (SF-12 PCS), short-form 12 mental component score (SF-12 MCS), PROMIS score, visual analog scale arm (VAS-arm) and neck (VAS-neck) pain scores. <h3>METHODS</h3> Duration of symptoms prior to surgery was recorded. HRQOLs, including NDI, SF-12 and VAS arm and neck were followed. Classic radiographic measurements of C2-C7 cob angle, cervical sagittal vertical axis (cSVA), and T1-Slope were assessed preoperatively to ensure that the cohorts were similar in terms of alignment. Patients were stratified whether they were diagnosed with anxiety/depression (A/D cohort) or not (non-A/D cohort). We compared outcome scores at each time point to determine if there was a difference in time to recovery for A/D patients.We tested normality of data using a Kolmogrov-Smirnov test. Student's t-test or Mann-Whitney test were used to compare normally and non-normally distributed HRQOLs respectively at each time point between the two cohorts. <h3>RESULTS</h3> There were 82 patients with at least 6-month follow-up (mean age 51.4±11.1 years old, 40 female). There were 16 patients in the A/D cohort. There were no significant differences in age (p=0.14), baseline radiographic parameters (all p>0.05), duration of symptoms (p=0.63) or preop HRQOLs (all p>0.77) between the A/D versus non-A/D. At 2 weeks, VAS-neck (p=0.04) and SF-12 MCS (p < 0.001) were worse for the A/D cohort. At 6 weeks, SF-12 MCS (p < 0.03) was less for the A/D cohort. At 3 months, SF-12 MCS (p<0.001) was worse for the A/D cohort. At final follow-up the only HRQOL that was statistically significant different between the cohorts was SF-12 MCS (54.5±8.4 vs 43.4±10.3, p<0.001) which was worse for the A/D cohort. <h3>CONCLUSIONS</h3> The impact of anxiety/depression on outcomes after 1-2 level ACDF/CDR is minimal. Specific HRQOL measures for mental health like SF-12 MCS will likely be lower in this population as we found within our dataset. Overall outcomes for patients with anxiety/depression mirror positive outcomes for those without these comorbid conditions after 1-2 level ACDF/CDR. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

The Effect of Esophageal Temperature Probes on Postoperative Dysphagia Following Primary Anterior Cervical Discectomy and Fusion: A Randomized Prospective Study.

The anterior approach to the cervical spine is associated with postoperative dysphagia. It is difficult to predict which patients are most at risk for dysphagia. The objective of this study was to determine if placing an esophageal temperature probe preoperatively would affect the severity and length of postoperative dysphagia. We hypothesize that use of an esophageal temperature probe would result in worse postoperative dysphagia at all measured time points as measured by the Swallowing-Quality of Life (SQAL-QOL) survey after anterior cervical discectomy and fusion (ACDF). A total of 44 patients were enrolled in a prospective, randomized controlled trial and randomized into groups: 1 with an esophageal temperature probe placed at the time of surgery and 2 without. A total of 39 patients filled out postoperative SWAL-QOL questionnaires at their preoperatives. Using the survey results, the data were analyzed between groups and subanalyzed based on number of operative levels and sex. SWAL-QOL scores for patients undergoing 2-level ACDF with an esophageal temperature probe were significantly better compared with those without a probe at 2 weeks and 6 months postoperatively. These results were not significant at other time points in in the overall analysis, but a trend toward improved dysphagia scores at each time point postoperatively was seen with the probe group. No differences were found between the 2 groups with respect to age at the time of surgery, sex, and preoperative SWAL-QOL score. Placement of an esophageal temperature probe at the time of surgery significantly improved postoperative dysphagia scores in patients undergoing 2-level ACDF at 2 weeks and 6 months postoperatively. 2 CLINICAL RELEVANCE: Placement of a temperature probe is a safe and effective technique that is readily available and easily applicable to the practice of spine surgery and may improve postoperative dysphagia after ACDF.

Biomechanical Evaluation of a Novel S-Type, Dynamic Zero-Profile Cage Design for Anterior Cervical Discectomy and Fusion with Variations in Bone Graft Shape: A Finite Element Analysis

Variations in cage design, material, and graft shape can affect osteointegration and adjacent segment range of motion (ROM) and stress after anterior cervical discectomy and fusion (ACDF) surgery. This study aimed to evaluate the biomechanical properties of a novel dynamic cervical cage design in both titanium (Ti) and polyether ether ketone (PEEK) with variations in bone graft shape using a single level ACDF (FE) model. A 3-dimensional C3-C6 FE model was developed using computed tomography scan data from a healthy male subject. The novel S-shaped dynamic interbody fusion cage with a zero-profile fixation was inserted at the C4-C5 level with 4 different bone graft shapes (square, circular, rectangular, and elliptical). Changes in segmental ROM and maximum von Mises stresses at the fusion and adjacent segments were analyzed. Both Ti and PEEK cages showed decreased ROM at the fusion and adjacent levels for all shapes of bone graft when compared with the intact spine model. The elliptical graft, for both Ti and PEEK cages, showed a lower percentage of reduction in segmental ROM at the fusion and adjacent levels (0%-5.6%) when compared with other graft shapes (0%-12%). Maximum stresses at the fusion level were lowest in Ti cage with elliptical graft (229.8-347.6 MPa) when compared with other shapes (241.2-476.2 MPa) in flexion, extension, and lateral bending. For the bone graft, maximum stresses were highest on the elliptical-shaped bone graft in flexion and extension in the Ti cage, and in flexion and lateral bending in the PEEK cage. Both Ti and PEEK cages showed decreased ROM at the fusion and adjacent levels for all shapes of bone graft when compared with the intact spine model. In the Ti and PEEK dynamic cages, the elliptical shape bone graft showed decreased stress on the cage and increased stress on the bone graft. Further experimental and clinical studies are needed to confirm these encouraging biomechanical results of this novel dynamic, zero-profile fusion device with elliptical bone graft in ACDF surgery.

Nonunion Rates After Anterior Cervical Discectomy and Fusion: Comparison of Polyetheretherketone vs Structural Allograft Implants

Although advances in implant materials, such as polyetheretherketone (PEEK), have been developed aimed to improve outcome after anterior cervical discectomy and fusion (ACDF), it is essential to confirm whether these changes translate into clinically important sustained benefits. To compare the radiographic and clinical outcomes of patients undergoing up to 3-level ACDF with PEEK vs structural allograft implants. In this cohort study, radiographic and symptomatic nonunion rates were compared in consecutive patients who underwent 1 to 3 level ACDF with allograft or PEEK implant. Prospectively collected clinical data and patient-reported outcome (PRO) scores were compared between the allograft and PEEK groups. Regression analysis was performed to determine the predictors of nonunion. In total, 194 of 404 patients met the inclusion criteria (79% allograft vs 21% PEEK). Preoperative demographic variables were comparable between the 2 groups except for age. The rate of radiographic nonunion was higher with PEEK implants (39%vs 27%, P=.0035). However, a higher proportion of nonunion in the allograft cohort required posterior instrumentation (14%vs 3%, P=.039). Patients with multilevel procedures and PEEK implants had up to 5.8 times the risk of radiographic nonunion, whereas younger patients, active smokers, and multilevel procedures were at higher risk of symptomatic nonunion. Along with implant material, factors such as younger age, active smoking status, and the number of operated levels were independent predictors of fusion failure. Given the impact of nonunion on PRO, perioperative optimization of modifiable factors and surgical planning are essential to ensure a successful outcome.

Does Myelopathy Increase the Morbidity and Mortality of Elective Single-Level Anterior Cervical Discectomy and Fusion? An Updated Propensity-Matched Analysis of 3938 Patients From the American College of Surgeons National Surgical Quality Improvement Program Database.

Myelopathy is thought to be associated with higher morbidity and mortality after anterior cervical discectomy and fusion (ACDF); however, the literature investigating this association has limitations. To investigate the influence of myelopathy on early perioperative complications of elective single-level ACDF. Patients who underwent ACDF between 2016 and 2018 were reviewed from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Propensity score matching analysis was used. Twenty percent of the cohort was myelopathic. These patients were significantly older, had more comorbidities, more likely to be functionally dependent, and to undergo emergency surgery when compared to the nonmyelopathic cohort. When 1969 myelopathic patients were 1:1 propensity matched with nonmyelopathic patients, there was no difference between the myelopathic and nonmyelopathic patients in incidence of postoperative intensive care unit admission or death. Patients in the myelopathic group were significantly more likely to have a nonhome discharge and less likely to be discharged on the first postoperative day. Myelopathic patients had a higher rate of return to operating room within the same admission (2.2%) as well as a higher unplanned readmission rate (4.2%). The total operation time (143 min) and average length of hospital stay (52 h) were significantly higher in the myelopathic group when compared to the nonmyelopathic group (117 min) and (33 h), respectively. Patients with myelopathy who undergo elective single-level ACDF have higher risks of several perioperative events including longer operative time, longer hospital stay, higher return to operating room, and unplanned readmission rates, when compared to nonmyelopathic patients. On the other hand, myelopathic patients did not exhibit higher mortality rate.

The impact of preoperative motor weakness on postoperative opioid use after ACDF

This study aims to determine if preoperative weakness is an isolated risk factor for prolonged postoperative opioid use after anterior cervical discectomy and fusion (ACDF). Patients with preoperative weakness were significantly more likely to have prolonged and inappropriate opioid use and have a single prescription mean morphine equivalent (MME) ≥ 200. Logistic regression isolated preoperative weakness, opioid tolerance, depression, and VAS Neck pain as independent predictors of extended opioid use. High postoperative opioid dose (MME ≥ 90) correlated with opioid tolerance, younger age, male sex, greater CCI, prior cervical surgery, and preoperative VAS Neck pain on regression.

Optimal Time Period of Wearing Protective Collar after Anterior Cervical Discectomy and Fusion

Objective: There is still no consensus on the time period of wearing protective collar after Anterior Cervical Discectomy and Fusion (ACDF). We aim to investigate the optimal time period of wearing collar after ACDF. Methods: We retrospectively reviewed patients with cervical spondylosis who underwent one or two segment ACDF during January 2016 and December 2017, and included 97 patients who met inclusion and exclusion criteria. Patients were divided into three groups, 1-4 week group, 5-8 week group and 9-12 week group, according to the actual time period of wearing collar after ACDF. We analyzed Japanese Orthopedic Association (JOA) score, Axial Symptom (AS) score and Neck Disability Index (NDI) before surgery and at post-operative 3 months to investigate the optimal time period of wearing collar after ACDF procedure. Results: 1) JOA score: All three groups have a better post-operative JOA score compared with that before surgery (paired t test, p&lt;0.05). There is no significant difference among the three groups with respect to post-operative JOA (ANOVA, p&gt;0.05). 2) AS score: The post-operative AS scores of 1-4 week group and 5-8 week group were significantly better than that before surgery (paired t test, p&gt;0.05). While the post-operative AS score of 9-12 week group was significantly worse than preoperative AS score (paired t test, p&lt;0.05). 3) NDI: All three groups have a better post-operative NDI compared with that before surgery (McNemar test, p&lt;0.05). Of note, in 5-8 weeks group, the percentage of no deficit increased by 45%, and the percentage of mild deficit decreased by 45% accordingly. That percentage is 26% and 31% in 1-4 week group and 9-12 week group, respectively. There was significant difference among these three groups (Fisher’s exact probability test, p&lt;0.05). Conclusion: For cervical spondylosis patients who underwent 1 or 2 segment ACDF, the optimal time period of wearing protective is 5-8 weeks. This time period results in comparable neurological outcome, least risk of axial symptoms, and highest chance of no deficit with neck function.

Surgery-related Factors Do Not Affect Short-term Adjacent Segment Kinematics After Anterior Cervical Arthrodesis.

Prospective cohort study. The aim of this study was to identify surgical factors that affect adjacent segment kinematics after anterior cervical discectomy and fusion (ACDF) as measured by biplane radiography. Previous studies investigated the effect of surgical factors on spine kinematics as a potential etiology for adjacent segment disease (ASD). Those studies used static flexion-extension radiographs to evaluate range of motion. However, measurements from static radiographs are known to be unreliable. Furthermore, those studies were unable to evaluate the effect of ACDF on adjacent segment axial rotation. Patients had continuous cervical spine flexion/exten- sion and axial rotation movements captured at 30 images per second in a dynamic biplane radiography system preoperatively and 1 year after ACDF. Digitally reconstructed radiographs generated from subject-specific CT scans were matched to biplane radiographs using a previously validated tracking process. Dynamic kinematics, postoperative segmental kyphosis, and disc distraction were calculated from this tracking process. Plate-to-disc distance was measured on postoperative radiographs. Graft type was collected from the medical record. Multivariate linear regression was performed to identify surgical factors associated with 1-year post-surgery changes in adjacent segment kinematics. A secondary analysis was also performed to compare adjacent segment kinematics between each of the surgical factors and previously defined thresholds believed to be associated with adjacent segment degeneration. Fifty-nine patients completed preoperative and postoperative testing. No association was found between any of the surgical factors and change in adjacent segment flexion/exten- sion or axial rotation range of motion (all P > 0.09). The secondary analysis also did not identify differences between adjacent segment kinematics and surgical factors (all P > 0.07). Following ACDF for cervical spondylosis, factors related to surgical technique were not associated with short-term changes in adjacent segment kinematics that reflect the hypermobility hypothesized to lead to the development of ASD.Level of Evidence: 2.

Return-to-Play Outcomes in Elite Athletes After Cervical Spine Surgery: A Systematic Review.

Return-to-play (RTP) outcomes in elite athletes after cervical spine surgery are currently unknown. To systematically review RTP outcomes in elite athletes after anterior cervical discectomy and fusion (ACDF), cervical disc replacement (CDR), or posterior foraminotomy (PF) surgery. EMBASE, PubMed, Cochrane, and Medline databases from inception until April 2020. Keywords included elite athletes, return to play, ACDF, foraminotomy, and cervical disc replacement. Eligible studies included those that reported RTP outcomes in elite athletes after cervical spine surgery. Systematic review. Level 4. Data were extracted by 2 independent reviewers. The primary outcomes of interest were rates and timing of RTP. Secondary outcomes included performance on RTP. A total of 1720 studies were initially screened. After inclusion criteria were applied, 13 studies with a total of 349 patients were included. A total of 262 (75%) played football, 37 (11%) played baseball, 19 (5%) played rugby, 10 (3%) played basketball, 10 (3%) played hockey, 9 (3%) were wresters, and 2 (1%) played soccer. ACDF was reported in 13 studies, PF in 3 studies, and CDR in 2 studies. The majority of studies suggest that RTP after surgical management is safe in elite athletes who are asymptomatic after their procedure and may lead to higher rates and earlier times of RTP. There is limited evidence regarding RTP or outcomes after CDR or multilevel surgery. The management and RTP in elite athletes after cervical spine injury is a highly complex and multifactorial topic. The overall evidence in this review suggests that RTP in asymptomatic athletes after both ACDF and PF is safe, and there is little evidence for decreased performance postoperatively. Surgical management results in a higher RTP rate compared with athletes managed conservatively.

Biomechanical effect of different plate-to-disc distance on surgical and adjacent segment in anterior cervical discectomy and fusion - a finite element analysis

BackgroundThe plate-to-disc distance (PDD) is an important factor affecting the degeneration of adjacent segments after anterior cervical discectomy and fusion (ACDF). However, the most suitable PDD is controversial. This study examined the adjacent intervertebral disc stress, bone graft stress, titanium plate stress and screw stress to evaluate the biomechanical effect of different PDD on surgical segment and adjacent segment following C5/C6 ACDF.MethodsWe constructed 10 preoperative finite element models of intact C4–C7 segments and validated them in the present study. We simulated ACDF surgery based on the 10 intact models in software. We designed three different distance of plate-to-disc titanium plates: long PDD (10 mm), medium PDD (5 mm) and short PDD (0 mm). The changes in C4/C5 and C6/C7 intervertebral disc stress, bone graft stress, titanium plate stress and screw stress were analyzed.ResultsThe von Mises stress of C4/C5 and C6/C7 intervertebral discs had no significant differences (P > 0.05) in three different PDD groups. Titanium plate stress increased as the PDD decreased. The bone graft stress and screws stress decreased as the PDD decreased. The maximum stress of each part occurred was mostly in the conditions of rotation and lateral bending.ConclusionsThe PDD has no effect on adjacent intervertebral disc stress, but it is an important factor that affecting the bone graft stress, titanium plate stress and screws stress after ACDF. Shorter PDD plate can provide better stability to reduce stress on screws and bone graft, which may be helpful to prevent cage subsidence, pseudarthrosis and instrument failure. This can serve as a reference for clinical choice of plate.

The Single Assessment Numeric Evaluation (SANE) after anterior cervical discectomy and fusion: A pilot study

Study designRetrospective cohort. ObjectivesTo evaluate the single assessment numerical evaluation (SANE) as a patient reported outcomes measure (PROM) after anterior cervical discectomy and fusion (ACDF), by comparing to legacy measures. MethodsWe included all patients undergoing ACDF with at least one year of follow up with complete PROM data. Patients completed the Neck Disability Index (NDI), the RAND-36 and the EuroQual Five Dimension (EQ-5D) scale, as well as the one-question SANE, pre- and post-operatively. Validity of SANE compared with other PROMs was determined utilizing Pearson’s correlation (ρ), proportional bias (B), responsiveness, minimal clinically important difference (MCID) and agreement. ResultsSixty-nine patients were included. There were moderate-to-strong correlations at a minimum of one-year follow-up between the SANE and NDI (ρ = −0.73, P < 0.0001), RAND (ρ = 0.80, P < 0.0001), and EQ-5D (ρ = −0.66, P < 0.0001). No significant proportional bias was found for the SANE when compared to the RAND (B = 0.03, p = 0.99), NDI (B = −0.003, p = 0.99), or EQ-5D (B = −0.0007, p = 0.99). Responsiveness for SANE was statistically similar to all other PROMs. The MCID for SANE was determined to be 10.5, with 42% of patients achieving the MCID. Bland-Altman plots demonstrated high agreement between all PROMs. ConclusionWe found the SANE score provides clinically important patient outcomes data after ACDF, despite only requiring answering one question. The SANE performs comparably to more burdensome health questionnaires. The SANE score may offer spine surgeons the option to easily and quickly collect clinically relevant data on their surgical patients.

The Short-Term to Midterm Follow-Up of Patients with Hirayama Disease After Anterior Cervical Discectomy and Fusion

Surgical treatment is widely used to treat patients with Hirayama disease (HD). However, postoperative follow-up with abundant samples is still scarce. This study investigated short-term to midterm clinical outcomes after anterior cervical discectomy and fusion (ACDF) among patients with HD. We enrolled 115 patients with HD who had undergone ACDF. Radiographic parameters included cervical lordosis (CL), sagittal vertical axis, segment lordosis (SL), T1 slope (T1S), T1S minus CL, range of motion (ROM), upper/lower adjacent segment ROM, and upper adjacent SL. Electrophysiologic parameters included the maximal compound muscle action potentials (CMAPs) of abductor digit minimi and abductor pollicis brevis, the latency of the ulnar nerve F reaction, and abnormal spontaneous action potentials. Clinical assessment included the selected brief-Michigan Hand Questionnaire and Odom scale. The average age was 19.5 ± 4.5 years. The mean follow-up time was 16.35 ± 9.21 months. CL, SL, and T1S increased, whereas sagittal vertical axis and ROM decreased at the final follow-up (P < 0.001). Upper adjacent SL, upper adjacent ROM, and lower adjacent ROM were stable after ACDF (P > 0.05). The maximal CMAPs of abductor digit minimi and the latency of the ulnar nerve F reaction improved bilaterally (P < 0.05), whereas there was no significance in the maximal CMAPs of abductor pollicis brevis (P > 0.05). Abnormal spontaneous action potentials reduced remarkably. The selected brief-Michigan Hand Questionnaire score increased after surgery (P < 0.001). The Odom scale showed a ratio of 79.1% (excellent and good ratio). This study showed favorable radiologic, electrophysiologic, and clinical outcomes after ACDF among patients with HD.

Reciprocal change of occipitocervical parameters after anterior cervical discectomy and fusion

To evaluate the reciprocal changes in occipitocervical parameters according to the recovery of cervical lordosis (CL) after anterior cervical discectomy and fusion (ACDF) in patients with sagittal imbalance. Sixty-five cases that underwent ACDF were followed. They were divided according to the recovery of the CL: Group 1 (ΔCL > 5°, 30 cases) and Group 2 (ΔCL < 5°, 35 cases). The following parameters were measured: occiput-cervical inclination (OCI), CL, occiput-C2 angle (OC2A), distance between external occipital protuberance and spinous process of C2 (OC2D), distance between spinous processes of C2 and C7 (C27D), and shortest distance between the plumb line of C2 body and posterosuperior corner of C7 (C27SVA). Overall, all parameters changed significantly after ACDF. Preoperative CL and preoperative C27D showed a correlation with ΔCL. ΔCL was negatively correlated with ΔC27D and ΔC27SVA. In Group 1, CL increased from − 2.60 ± 1.88° to 11.57 ± 1.83°, OC2A decreased from 23.96 ± 2.05° to 19.87 ± 1.36°, OC2D increased from 82.96 ± 1.48 mm to 86.50 ± 1.81 mm, C27D decreased from 95.61 ± 2.66 mm to 87.01 ± 2.50 mm, and C27SVA decreased from 24.14 ± 2.20 mm to 17.06 ± 2.14 mm. In Group 2, only OCI decreased significantly after ACDF. ACDF can increase CL postoperatively in patients with cervical sagittal imbalance. Patients with significant CL recovery after ACDF showed a reciprocal change in occipitocervical parameters. (OC2A, OC2D).

Risk factors for postoperative dysphagia and dysphonia following anterior cervical spine surgery: a comprehensive study utilizing the hospital for special surgery dysphagia and dysphonia inventory (HSS-DDI)

BACKGROUND CONTEXTPostoperative dysphagia and dysphonia (PDD) are prevalent complications after anterior cervical discectomy and fusion (ACDF). Identification of risk factors for these complications is necessary for effective prevention. Recently, patient reported outcome measures (PROM) have been used to determine PDD after ACDF. The Hospital for Special Surgery Dysphagia and Dysphonia Inventory (HSS-DDI) is a validated PROM that specifically assesses dysphagia and dysphonia after anterior cervical spine surgery. PURPOSETo identify the perioperative risk factors for PDD utilizing the HSS-DDI. STUDY DESIGN/SETTINGObservational study of prospectively collected data at a single academic institution. PATIENT SAMPLEPatients undergoing anterior cervical discectomy and fusion from 2015 to 2019 who enrolled in the prospective data collection. OUTCOME MEASUREThe HSS-DDI administered 4 weeks, 8 weeks, and 4-6 months after surgery. METHODSAs potential risk factors, the data on demographic factors, analgesic medications, history of psychiatric illness, preoperative sagittal alignment, surgical factors, preoperative diagnoses, and preoperative Neck Disability Index (NDI) scores were collected. Bivariate and multivariable regression analyses utilizing the Tobit model were conducted. RESULTS291 patients were included in the final analysis. The median HSS-DDI at 4-weeks, 8 weeks, and 4-6 months postoperatively, were 80.7, 92.7, and 98.4, respectively. Multivariable analysis demonstrated that current smoking, previous cervical spine surgery, preoperative C2-7 angle, upper level surgery, multilevel surgery, opioid use, and a high preoperative NDI score, were independent contributing factors to a low HSS-DDI score at 4-weeks follow-up. Intraoperative topical steroid use was an independent protective factor for a low HSS-DDI score. Opioid use and high NDI score remained independent factors at 4-6 months. Sub-domain analysis demonstrated that prior cervical surgery, preoperative C2-7 angle, multilevel surgery, and intraoperative topical steroid use were significant for dysphagia only. Current smoking was significant for dysphonia only. CONCLUSIONSOur results showed that preoperative opioid use and a high preoperative NDI score are novel independent risk factors for postoperative dysphagia and dysphonia in addition to other known factors.

Titanium-interlayer mediated hydroxyapatite coating on polyetheretherketone: a prospective study in patients with single-level cervical degenerative disc disease

BackgroundCurrently, there are limited reports regarding investigation of the biological properties of polyetheretherketone (PEEK) coated with titanium (Ti) and hydroxyapatite (HA) in human. The objective of this study is to evaluate the in vivo response of the PEEK cages coated with Ti and HA versus uncoated PEEK cages after anterior cervical discectomy and fusion (ACDF) in patients with single-level cervical degenerative disc disease (CDDD).MethodsTwenty-four patients with PEEK cages coated with Ti and HA (PEEK/Ti/HA group) were matched one-to-one with patients with uncoated PEEK cages (PEEK group) based on age, gender, and operative segment. All patients had been followed up for more than 2 years. Radiological assessments included intervertebral height (IH), C2-7 angle (C2-7a), segmental alignment (SA), and fusion rate. Clinical parameters included Visual Analogue Scale (VAS) and Japanese Orthopedic Association (JOA) scores.ResultsThere was no statistical difference in SA, IH, and C2-7a between the two groups before and after surgery and all these parameters were restored postoperatively. The fusion rate of PEEK/Ti/HA group was significantly higher than PEEK group at 3-month post-operation (87.5% vs. 62.5%). At the last follow-up, the fusion rate of the both groups achieved 100%. The VAS and JOA scores were comparable between two groups and improved postoperatively.ConclusionsIn patients with single-level ACDF, PEEK cage coated with Ti and HA provided a higher fusion rate than uncoated PEEK cage at 3-month post-operation, while both two cages could achieve solid osseous fusion at the last follow up. Compared with the uncoated PEEK cage, PEEK/Ti/HA cage yielded similar favorable segmental and overall cervical lordosis, IH, and clinical outcomes after the surgery.

Does Graft Position Affect Subsidence After Anterior Cervical Discectomy and Fusion?

Study Design:Retrospective cohort study.Objective:Implant subsidence is an important prognostic factor after anterior cervical discectomy and fusion (ACDF). Our purpose in this study was to investigate whether graft position affects subsidence after ACDF and to determine if there is a difference in clinical results based on allograft subsidence and position.Methods:We reviewed 92 patients who underwent single-level ACDF with allograft and plate between January 2012 and October 2018. Treatment levels were divided based on allograft position within 2 mm of the posterior margin of the augmented plate (Anterior group) or at greater than 2 mm (Center group). Subsidence was defined as segmental vertebral body height decrease of 2 mm or more at 1 year compared to 1 week after surgery.Results:Overall subsidence prevalence was 15 (16%) cases. Subsidence was 11% in the Anterior group (8/73) and 39% in the Center group (7/19; P = .012). The subsidence group showed smaller graft footprint size (graft/endplate ratio) compared with the nonsubsidence group, and pseudarthrosis occurred frequently in the subsidence. There was no significant difference in clinical results according to graft position. These findings indicate that anterior graft position reduces risk of subsidence (95% confidence interval = 0.085-0.949).Conclusion:To minimize risk of subsidence, the graft should be positioned on the anterior position of the surgical-level endplate. In addition, using a graft appropriate for endplate size will further reduce subsidence.

The effect of the difference in C2\u20137 angle on the occurrence of dysphagia after anterior cervical discectomy and fusion with the zero-P implant system

ObjectivesTo investigate the effect of the difference in C2–7 angle on dysphagia after anterior cervical discectomy and fusion (ACDF) with the Zero-P Implant System.MethodsA retrospective analysis of 181 patients who underwent ACDF with the Zero-P Implant System and had at least one year of follow-up from January 2011 to November 2018 was performed. All patients were divided into a non-dysphagia group and a dysphagia group to explore the effect of the difference between postoperative and preoperative C2–7 angle (dC2–7A) on postoperative dysphagia. At the same time, other possible related factors including the difference between postoperative and preoperative O-C2 angle (dO-C2A), sex, age, body mass index (BMI), intraoperative time, estimated blood loss, diabetes mellitus, hypertension, smoking, alcohol consumption, prevertebral soft-tissue swelling (PSTS), the highest segment involved in the surgery and the levels of surgery segments were analyzed.ResultsIn total, the non-dysphagia group comprised 139 patients and the dysphagia group comprised 42 patients. The single-factor analysis showed that smoking, PSTS and dC2–7A were significantly different between the two groups (P < 0.05). Spearman’s correlation coefficient showed no significant correlation between the degree of dysphagia and dC2–7A (P > 0.05). The results of the multiple-factor analysis with an ordinal logistic regression model showed that smoking, PSTS and dC2–7A were significantly associated with the incidence of dysphagia (P < 0.05).ConclusionsThe postoperative C2–7 angle has an important effect on the occurrence of dysphagia in patients undergoing Zero-P implant system interbody fusion surgery.

S3444 Balloon Dilation of an Upper Esophageal Stricture as a Complication of Anterior Cervical Discectomy Fusion Surgery (ACDF) Using an Ultrathin Scope and Seldinger Wire Technique

INTRODUCTION: Dysphagia after anterior cervical discectomy and fusion (ACDF) surgery is a frequent and well-known complication however the pathophysiology of dysphagia is unclear and there is sparse data on the best methods for evaluation and treatment. CASE DESCRIPTION/METHODS: A 64 year-old female was seen in the Gastroenterology clinic for complaints of dysphagia primarily to solids and pills and an unintentional weight loss of nearly 20 pounds after a C3-C4 ACDF was performed earlier in the year. At the index endoscopy, a standard-sized endoscope could not pass through the upper esophagus and the procedure required completion with an ultrathin (UT) endoscope. A barium swallow following the case revealed a focal stricture 4 × 7mm in diameter just below the ACDF site. To attempt dilation during a subsequent endoscopy, a wire was placed through the UT scope and the scope was removed. A through-the-scope (TTS) balloon was pre-loaded into a standard endoscope and the wire was then placed through the balloon. The scope was advanced using a Seldinger wire technique and the balloon was dilated in the upper esophagus being careful to avoid a large osteophyte at C-7 found on prior MRI. The patient required three sessions with wire exchange and dilation up to a max of 15mm resulting in the ability to pass a standard endoscope through the upper esophagus. Since the last endoscopy, the patient has had improvement in her dysphagia with significant weight gain within 2 months post-procedure. DISCUSSION: Up to 15% of ACDF patients can still present with dysphagia one year post-op however the exact causes are largely unknown and therapeutic strategies have not been described. Management of complex strictures in the setting of recent cervical spine surgery can be challenging however lessons learned from our case include the importance of careful imaging review to avoid potential complications (such as dilating against an osteophyte), use of the UT scope to navigate the stricture and employment of the Seldinger technique to accommodate focal balloon dilation which can be successfully employed for upper esophageal strictures.