Artificial disc replacement and adjacent-segment pathology: 10-year outcomes of a randomized trial.

OBJECTIVE: Artificial disc replacement (ADR) is designed to preserve motion and thus protect against adjacent-segment pathology (ASP) and act as an alternative treatment to fusion surgery. The question remains, how well do ADR devices perform after 10 years of follow-up compared with fusion surgery in terms of patient satisfaction, sustainability, and protection against ASP? METHODS: This was the 10-year follow-up study of 153 participants who underwent ADR or fusion surgery after anterior decompression due to cervical degenerative radiculopathy (ISRCTN registration no. 44347115). Scores on the Neck Disability Index (NDI), EQ-5D, and visual analog scale for neck and arm pain were obtained from the Swedish Spine Registry and analyzed using ANCOVA. Information about secondary surgical procedures was collected from medical records and presented as Kaplan-Meier curves. MRI and flexion-extension radiography were performed, and ASP was graded according to the Miyazaki classification system. RESULTS: Ten participants were lost to follow-up, which left 143 participants (80 underwent ADR and 65 underwent anterior cervical discectomy and fusion). There were no differences between groups in terms of patient-reported outcome measures (10-year difference in NDI scores 1.7 points, 95% CI -5.1 to 8.5, p = 0.61). Nineteen (24%) participants in the ADR group compared with 9 (14%) in the fusion group underwent secondary surgical procedures. The higher reoperation rate of the ADR group was mainly due to 11 female participants with device loosening. The rates of reoperation due to ASP were similar between groups, which was confirmed with MRI assessment of ASP that also showed no differences between the groups (p = 0.21). CONCLUSIONS: This was the first 10-year follow-up study to compare ADR with fusion surgery and to provide MRI information for the assessment of ASP. The authors found no benefit of ADR over fusion surgery after anterior decompression for cervical degenerative radiculopathy.

Unintended fusion in cervical artificial disk replacement: a prospective study on heterotopic ossification, progression, and clinical outcome, with 5-year follow-up.

PURPOSE: Heterotopic ossification (HO) may cause unintended fusion in artificial disk replacement (ADR), failing to preserve motion. The reported incidence of HO varies hugely. This study aimed to determine prevalence of HO, progression, predisposing factors to occurrence and to progression, and potential effect on clinical outcomes. METHODS: Eighty-three patients treated with ADRs for cervical radiculopathy at one or two segments were extracted from a previously published RCT. Of the 83 patients, 59 had remaining ADR (79 implants) and sufficiently high-quality X-rays at 5 years of follow-up to allow analysis. HO was graded on plain films according to Mehren/Suchomel. Prevalence, progression, predisposing factors and effect on clinical outcome (Neck Disability Index-NDI) were analyzed. RESULTS: At 2 years, HO was seen in 46/55 ADR implants (84%), severe enough to affect mobility in 27/55 (49%). At 5 years, HO was seen in 92% of 79 implants, severe in 71%. Male sex was a predisposing factor to HO. No predisposing factors to progression were identified. NDI was not affected by the severity of HO. CONCLUSION: Almost all ADR implants in our study have HO at 5 years of follow-up. Male sex is a risk factor. Severe HO did not affect clinical outcome. TRIAL REGISTRATION: Study registered at ISRCTN (registration number: 44347115).

Accuracy and Reliability of X-ray Measurements in the Cervical Spine.

STUDY DESIGN: This study is a post hoc analysis of a multicenter prospective randomized controlled trial which compared artificial disc replacement and anterior cervical discectomy and fusion. PURPOSE: Useful radiographic parameters for assessing cervical alignment include the Cobb angles, T1 slope (T1S), occipitocervical inclination (OCI), K-line tilt (KLT), and cervical sagittal vertical axis (cSVA). This study aimed to determine measurement accuracy and reliability for these parameters. OVERVIEW OF LITERATURE: Various authors have assessed repeatability by comparing different methods of measurement, but knowledge of measurement error and minimal detectable change is scarce. METHODS: We evaluated 758 lateral cervical radiographs. One medical student and one spine surgeon (i.e., measured ×2 within 4 weeks) independently measured the parameters obtaining 5,850 values. Standard error of measurement (SEm) and minimum detectable change (MDC) were calculated for each parameter. The accuracy and reliability of the Cobb angle measurements were calculated for the different types of angles: cervical lordosis, prosthesis angle, segmental angle with two bone surfaces (SABB), and segmental angle with one bone and one metal surface. Reliability was determined with intraclass correlation coefficient (ICC). RESULTS: SEm was 1.8° and MDC was 5.0° for the Cobb angle, with an intraobserver/interobserver ICC of 0.958/0.886. All the different subtypes of Cobb angles had an ICC higher than 0.950, except SABB (intraobserver/interobserver ICC of 0.922/0.716). The most accurate and reliable measurement was for KLT. CONCLUSIONS: This study provides normative data on SEm and MDC for Cobb angles, T1S, KLT, OCI, and cSVA in cervical lateral radiographs. Reliability was excellent for all parameters except SABB (e.g., good).

Artificial disc replacement versus fusion in patients with cervical degenerative disc disease and radiculopathy: a randomized controlled trial with 5-year outcomes.

In BriefIn this study the authors compare cervical arthroplasty with fusion surgery in a randomized controlled trial using patient-reported outcome measures and MRI after 5 years of follow-up. Because the main purpose of arthroplasties is to prevent adjacent-segment pathology, it is important to investigate if that is actually realized in practice.

Artificial disc replacement versus fusion in patients with cervical degenerative disc disease with radiculopathy: 5-year outcomes from the National Swedish Spine Register.

OBJECTIVE: The long-term efficacy of artificial disc replacement (ADR) surgery compared with fusion after decompression for the treatment of cervical degenerative disc disease and radiculopathy has not previously been investigated in a population-based setting. METHODS: All patients with cervical degenerative disc disease and radiculopathy who were in the national Swedish Spine Registry (Swespine) beginning in January 1, 2006, were eligible for the study. Follow-up information was obtained up to November 15, 2017. The authors compared, using propensity score matching, patients treated with anterior decompression and insertion of an ADR with patients who underwent anterior decompression combined with fusion surgery. The primary outcome was the Neck Disability Index (NDI), a patient-reported function score ranging from 0% to 100%, with higher scores indicating greater disability and a minimum clinically important difference of > 15%. RESULTS: A total of 3998 patients (2018:1980 women/men) met the inclusion criteria, of whom 204 had undergone arthroplasty and 3794 had undergone fusion. After propensity score matching, 185 patients with a mean age of 49.7 years remained in each group. Scores on the NDI were approximately halved in both groups after 5 years, but without a significant mean difference in NDI (3.0%; 95% CI -8.4 to 2.4; p = 0.28) between the groups. There were no differences between the groups in EuroQol-5 Dimensions or in pain scores for the neck and arm. CONCLUSIONS: In patients with cervical degenerative disc disease and radiculopathy, decompression plus ADR surgery did not result in a clinically important difference in outcomes after 5 years, compared with decompression and fusion surgery.

Effects of preoperative mental distress versus surgical modality, arthroplasty, or fusion on long-term outcome in patients with cervical radiculopathy.

OBJECTIVE: Several efforts have been made to investigate the long-term efficacy of artificial disc replacement surgery compared with that of fusion after decompression for the treatment of cervical degenerative disc disease and radiculopathy. However, research on the impact of mental distress on surgical treatment outcome has been sparse. The aim of the authors was to investigate the potential predictive value of preoperative risk factors in determining long-term outcome. METHODS: A total of 153 patients (mean age 47 years) with single- or double-level cervical degenerative disc disease and radiculopathy were randomly assigned to undergo either anterior cervical discectomy and fusion (n = 70) or artificial disc replacement (n = 83). The primary outcome was the Neck Disability Index (NDI) score, a patient-reported function score that ranges from 0% to 100%; higher scores indicate greater disability. Preoperative variables such as sex, age, smoking status, employment status, having a strenuous job, neck pain duration, arm pain duration, amount of regular exercise, Hospital Anxiety and Depression Scale (HADS) score, NDI score, whether surgery was performed on 1 or 2 levels, and allocated treatment were analyzed in multiple linear regression models with the 5-year NDI score as the outcome. RESULTS: A total of 47 (31%) patients had either a HADS anxiety or HADS depression score of 10 points or higher. High values on the preoperative HADS were a negative predictor of outcome (p = 0.009). Treatment allocation had no effect on 5-year NDI scores (p = 0.32). CONCLUSIONS: Preoperative mental distress measured with the HADS affects long-term outcome in surgically treated patients with cervical radiculopathy.

Validation of the visual analog scale in the cervical spine.

OBJECTIVE The visual analog scale (VAS) is frequently used to measure treatment outcome in patients with cervical spine disorders. The minimum clinically important difference (MCID) is the smallest change in a score that has clinical importance to the patient. Although it has been established for other medical fields, knowledge of the VAS MCID for the cervical spine is sparse, and it has rarely been considered in relation to measurement noise. The goals in this study were as follows: 1) to validate the VAS-neck and VAS-arm instruments for the cervical spine (e.g., repeatability); 2) to investigate the possible influence of predictive factors and the Hospital Anxiety and Depression Scale (HADS) score on repeatability; and 3) to compute the MCID with 5 different methods. METHODS A post hoc analysis of a prospective randomized controlled trial with 151 patients undergoing surgery for cervical radiculopathy due to degenerative disc disease was performed. Information on age, sex, smoking habits, exercise, employment status, HADS score, and VAS-neck and VAS-arm scores was gathered before surgery and after 1 year. The VAS was applied twice on every occasion, with 15 minutes in between. Repeatability and the association with predictors and HADS score were analyzed using the 1-sample t-test, linear regression models, and Spearman correlation. The MCID was calculated with the following methods: average change, change difference, receiver operating characteristic curve, effect size, and minimum detectable change (MDC). RESULTS The repeatability in VAS-neck was 8.1 mm, and in VAS-arm it was 10.4 mm. Less consistent values on the VAS correlated to female sex and higher values on the HADS. For VAS-neck the MCID ranged from 4.6 to 21.4, and for VAS-arm it ranged from 1.1 to 29.1. The highest MCID came from the MDC method, which was the only method that gave values above the measurement noise in both VAS-neck and VAS-arm. CONCLUSIONS Measurement noise in VAS-neck and VAS-arm for the cervical spine was influenced by female sex and HADS score. The only method to compute MCID that consistently gave results above the measurement noise in VAS-neck and VAS-arm was the MDC. Clinical trial registration no.: 44347115 ( www.isrctn.com ).

Effectiveness, costs and cost-effectiveness of chiropractic care and physiotherapy compared with information and advice in the treatment of non-specific chronic low back pain: study protocol for a randomised controlled trial.

BACKGROUND: Low back pain is a global public health problem and a leading cause of disability all over the world. The lifetime prevalence of low back pain is 70-80% and a significant proportion of people affected develop chronic low back pain (CLBP). Besides a severe negative impact on people's health and health-related quality of life, CLBP is associated with substantial costs for society. Medical costs for the management of CLBP and costs for production losses due to absenteeism from work are sizeable. Pharmaceuticals, physical activity, manipulation, and multidisciplinary rehabilitation interventions are examples of widely used treatments for CLBP. However, the scientific basis to recommend the use of one treatment over another is limited and more research is needed to study the effects, costs and cost-effectiveness of treatments for CLBP in clinical practice. The aim of the study is to evaluate the effectiveness (back pain-related functional limitation, back pain intensity, general health, health-related quality of life, and working status), costs (medical costs and costs for production losses) and cost-effectiveness of chiropractic care and physiotherapy when added to information and advice in the treatment of patients with non-specific CLBP in Sweden. METHODS/DESIGN: This is a pragmatic randomised controlled trial, where participants are recruited through six primary care rehabilitation units (PCRUs) in Stockholm County Council, Sweden. Individuals with non-specific CLBP are individually randomised to one of four treatment groups: 'information and advice'; 'physiotherapy, and information and advice'; 'chiropractic care, and information and advice'; or 'chiropractic care, physiotherapy, and information and advice'. A sample size of 600 participants will be recruited during a period of 33 months. A computer-based questionnaire is used to collect data on back pain-related functional limitation (Oswestry Disability Index), pain intensity (Numeric Rating Scale), general health (self-rated health), health-related quality of life (EQ-5D-3L), and working status (measured as percentage of full-time work). Data will be collected at baseline, and at 3, 6, and 12 months after baseline. DISCUSSION: The results from our study should be considered when producing evidence-based guidelines and recommendations on which treatment strategies to use for CLBP. TRIAL REGISTRATION: ISRCTN registry, ID: ISRCTN15830360 . Registered prospectively on 2 February 2017.

Higher reoperation rate following cervical disc replacement in a retrospective, long-term comparative study of 715 patients.

PURPOSE: To evaluate rates of secondary surgical interventions in a cohort treated with fusion (ACDF), artificial disc replacement (ADR) or a posterior surgical procedure (PP) because of a cervical degenerative pathology. METHODS: 715 patients treated with any primary cervical surgical intervention between the years 2000 and 2010 were retrospectively evaluated regarding frequency of secondary surgery between the years 2000 and 2015, thus giving a follow-up time of minimum 5 years. Reasons for secondary surgery as well as choice of new intervention were evaluated. Data were collected from a single-center setting. RESULTS: Follow-up rate was 94%. 79 (11%) patients in total underwent a new operation during follow-up. 50/504 (10%), 27/172 (15%), and 2/39 (5%) of the patients had a second surgical intervention in the ACDF, ADR, and PP groups, respectively. There was a statistically significant higher rate of repeated surgery in the ADR group compared to the ACDF group, OR 1.7 (CI 1.06-2.8), p = 0.03. Risk for repeated surgery at index level was even higher for ADR, OR 5.1 (CI 2.4-10.7), p < 0.001. Reoperation rate because of ASD in the whole cohort did not differ between ACDF and ADR groups, p = 0.40. CONCLUSION: The group initially treated with artificial disc replacement showed higher rate of reoperations and more implant-related complications. In this cohort, artificial disc replacement was not protective against reoperation because of adjacent segment pathology.

Pain drawings predict outcome of surgical treatment for degenerative disc disease in the cervical spine.

INTRODUCTION: Pain drawings have been frequently used in the preoperative evaluation of spine patients. For lumbar conditions comprehensive research has established both the reliability and predictive value, but for the cervical spine most of this knowledge is lacking. The aims of this study were to validate pain drawings for the cervical spine, and to investigate the predictive value for treatment outcome of four different evaluation methods. METHODS: We carried out a post hoc analysis of a randomized controlled trial, comparing cervical disc replacement to fusion for radiculopathy related to degenerative disc disease. A pain drawing together with Neck Disability Index (NDI) was completed preoperatively, after 2 and 5 years. The inter- and intraobserver reliability of four evaluation methods was tested using κ statistics, and its predictive value investigated by correlation to change in NDI. RESULTS: Included were 151 patients, mean age of 47 years, female/male: 78/73. The interobserver reliability was fair for the modified Ransford and Udén methods, good for the Gatchel method, and very good for the modified Ohnmeiss method. Markings in the shoulder and upper arm region on the pain drawing were positive predictors of outcome after 2 years of follow-up, and markings in the upper arm region remained a positive predictor of outcome even after 5 years of follow-up. CONCLUSIONS: Pain drawings were a reliable tool to interpret patients' pain prior to cervical spine surgery and were also to some extent predictive for treatment outcome.

Anxiety and depression affect pain drawings in cervical degenerative disc disease.

INTRODUCTION: Pain drawings have been frequently used in the preoperative evaluation of spine patients. Until now most investigations have focused on low back pain patients, even though pain drawings are used in neck pain patients as well. The aims of this study were to investigate the pain drawing and its association to preoperative demographics, psychological impairment, and pain intensity. METHODS: We carried out a post hoc analysis of a randomized controlled trial, comparing cervical disc replacement to fusion for radiculopathy related to degenerative disc disease. Preoperatively the patients completed a pain drawing, the Hospital Anxiety and Depression Scale (HADS), and a visual analogue scale (VAS). The pain drawing was evaluated according to four established methods, now modified for cervical conditions. Comparisons were made between the pain drawing and age, sex, smoking, and employment status as well as HADS and VAS. RESULTS: Included were 151 patients, mean age of 47 years, female/male: 78/73. Pain drawing results were not affected by age, sex, smoking, and employment status. Patients with non-neurogenic pain drawings according to the modified method by Ransford had higher points on HADS-anxiety, HADS-depression, and HADS-total. Patients with markings in the head region had higher score on HADS-depression. Markings in the neck and lower arm region were associated with high values of VAS-neck and VAS-arm. CONCLUSIONS: Pain drawings were affected by both pain intensity and anxiety/depression in cervical spine patients. Therefore, the pain drawing can be a useful tool when interpreting the patients' pain in correlation to psychological impairment and pain location.

The association between preoperative mental distress and patient-reported outcome measures in patients treated surgically for cervical radiculopathy.

BACKGROUND CONTEXT: Previous research indicates that there might exist a link between the experience of pain and mental distress. Pain can possibly trigger anxiety and chronic pain, as well as also depression. On the other hand, anxiety and depression might also be risk factors for painful conditions and more pronounced subsequent disability and thus, the pathways may be bidirectional. Expanded knowledge of how different factors affect pain and function may help surgeons in preoperative decision-making. PURPOSE: The aim of this study was to evaluate the impact of potential preoperative risk factors with special reference to mental distress. STUDY DESIGN/SETTING: This is a prospective outcome study in a cohort from a multicenter randomized controlled trial comparing anterior cervical decompression and fusion with disc replacement. PATIENT SAMPLE: The sample included 151 patients with cervical radiculopathy planned for surgery. OUTCOME MEASURES: Surgical outcome was evaluated with Neck Disability Index (NDI), health related quality-of-life with European Quality of Life-5 Dimensions, and pain with visual analogue scale for arm and neck. Mental distress was preoperatively measured with the Hospital Anxiety and Depression (HAD) scale. METHODS: Preoperative data regarding possible risk factors for poor outcome were analyzed in multiple linear regression models with postoperative NDI and change of NDI as dependent factors. Patients with high preoperative levels of anxiety or depression (H-HAD), indicating mental distress, were compared with patients scoring low/moderate levels (L-HAD) regarding patient-reported outcome measures (PROMs) preoperatively and at 1- and 2-year follow-up. RESULTS: Outcome data were available for 136 patients at the 2-year follow-up. No statistically significant difference in any outcome data could be demonstrated between the two surgical treatment groups. Mental distress was the variable most strongly associated with NDI at 2 years in the regression analysis. There were 42 patients classified as H-HAD and 94 as L-HAD. The average improvement in NDI was 16.9 in the H-HAD group and 26.3 in the L-HAD group, p=.02. The H-HAD patients showed a tendency for poorer baseline data and worse outcome overall in all PROMs at follow-up at both 1 and 2 years. CONCLUSIONS: Preoperative mental distress measured with HAD was associated with worse outcome overall. More research is needed to investigate whether patients with mental distress may achieve better results if other treatments are offered, either as non-surgical treatment alone or as an adjunct to surgery.

Evaluation of mobility and stability in the Discover artificial disc: an in vivo motion study using high-accuracy 3D CT data.

OBJECT: Artificial disc replacement (ADR) devices are unlike implants used in cervical fusion in that they are continuously exposed to stress not only within the implant site but also at their site of attachment to the adjacent vertebra. An imaging technique with higher accuracy than plain radiography and with the possibility of 3D visualization would provide more detailed information about the motion quality and stability of the implant in relation to the vertebrae. Such high-accuracy studies have previously been conducted with radiostereometric analysis (RSA), which requires implantation of tantalum markers in the adjacent vertebrae. The aim of this study was to evaluate in vivo motion and stability of implanted artificial discs. A noninvasive analysis was performed with CT, with an accuracy higher than that of plain radiographs and almost as high as RSA in cervical spine. METHODS: Twenty-eight patients with ADR were included from a larger cohort of a randomized controlled trial comparing treatment of cervical radiculopathy with ADR or anterior cervical decompression and fusion. Surgical levels included C4-7; 18 patients had 1-level surgery and 10 patients had 2-level surgery. Follow-up time ranged from 19 to 50 months, with an average of 40 months. Two CT volumes of the cervical spine, 1 in flexion and 1 in extension, were obtained in each patient and then spatially registered using a customized imaging tool, previously used and validated for the cervical spine. Motion between the components in the artificial disc, as well as motion between the components and adjacent vertebrae, were calculated in 3 planes. Intraclass correlation (ICC) between independent observers and repeatability of the method were also calculated. RESULTS: Intrinsic motion, expressed as degrees in rotation and millimeters in translation, was detectable in a majority of the ADRs. In the sagittal plane, in which the flexion/extension was performed, sagittal rotation ranged between 0.2° and 15.8° and translation between 0.0 and 5.5 mm. Eight percent of the ADRs were classified as unstable, as motion between at least 1 of the components and the adjacent vertebra was detected. Five percent were classified as ankylotic, with no detectable motion, and another 8% showed very limited motion due to heterotopic ossification. Repeatability for the motion in the sagittal plane was calculated to be 1.30° for rotation and 1.29 mm for translation (95% confidence level), ICC 0.99 and 0.84, respectively. All 3 patients with unstable devices had undergone 1-level ADRs at C5-6. They all underwent revision surgery due to increased neck pain, and instability was established during the surgery. CONCLUSIONS: The majority of the artificial discs in this study showed intrinsic mobility several years after implantation and were also shown to be properly attached. Implant instability was detected in 8% of patients and, as all of these patients underwent revision surgery due to increasing neck pain, this might be a more serious problem than heterotopic bone formation.

The Discover artificial disc replacement versus fusion in cervical radiculopathy--a randomized controlled outcome trial with 2-year follow-up.

BACKGROUND CONTEXT: Several previous studies comparing artificial disc replacement (ADR) and fusion have been conducted with cautiously positive results in favor of ADR. This study is not, in contrast to most previous studies, an investigational device exemption study required by the Food and Drug Administration for approval to market the product in the United States. This study was partially funded with unrestricted institutional research grants by the company marketing the artificial disc used in this study. PURPOSE: To compare outcomes between the concepts of an artificial disc to treatment with anterior cervical decompression and fusion (ACDF) and to register complications associated to the two treatments during a follow-up time of 2 years. STUDY DESIGN/SETTING: This is a randomized controlled multicenter trial, including three spine centers in Sweden. PATIENT SAMPLE: The study included patients seeking care for cervical radiculopathy who fulfilled inclusion criteria. In total, 153 patients were included. OUTCOME MEASURES: Self-assessment with Neck Disability Index (NDI) as a primary outcome variable and EQ-5D and visual analog scale as secondary outcome variables. METHODS: Patients were randomly allocated to either treatment with the Depuy Discover artificial disc or fusion with iliac crest bone graft and plating. Randomization was blinded to both patient and caregivers until time for implantation. Adverse events, complications, and revision surgery were registered as well as loss of follow-up. RESULTS: Data were available in 137 (91%) of the included and initially treated patients. Both groups improved significantly after surgery. NDI changed from 63.1 to 39.8 in an intention-to-treat analysis. No statistically significant difference between the ADR and the ACDF groups could be demonstrated with NDI values of 39.1 and 40.1, respectively. Nor in secondary outcome measures (EQ-5D and visual analog scale) could any statistically significant differences be demonstrated between the groups. Nine patients in the ADR group and three in the fusion group underwent secondary surgery because of various reasons. Two patients in each group underwent secondary surgery because of adjacent segment pathology. Complication rates were not statistically significant between groups. CONCLUSIONS: Artificial disc replacement did not result in better outcome compared to fusion measured with NDI 2 years after surgery.

Comparison of dysphagia between cervical artificial disc replacement and fusion: data from a randomized controlled study with two years of follow-up.

STUDY DESIGN: Prospective randomized controlled trial. OBJECTIVE: To determine and explain any differences in self-reported dysphagia between patients treated with artificial disc replacement and anterior cervical decompression and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Dysphagia after anterior cervical spine surgery has in previous studies been evaluated regarding different influencing factors. Surgical technique, number of treated levels, and type of implant has been shown to be of possible importance. METHODS: One hundred thirty-six patients from a randomized controlled trial between artificial disc replacement and ACDF in 1 or 2 surgical levels were evaluated regarding dysphagia. Evaluation was done with the dysphagia short questionnaire preoperatively, at 4 weeks, 3 months, and 1 and 2 years postoperatively. Reconstruction in the artificial disc replacement group was performed with the Discover artificial disc. Bone graft and anterior plating was used in the ACDF group. Type of implant was blinded to the patients and the surgeon until time of implantation. RESULTS: Demographics and dysphagia short questionnaire levels were similar in both groups preoperative. At 4 weeks of follow-up postoperatively, dysphagia was significantly higher in both groups than baseline levels, P < 0.01. No significant differences were seen between the groups until follow-up at 2 years, which showed significantly higher dysphagia short questionnaire levels in the ACDF group, P = 0.04. The difference was statistically significant in both patients treated with 1- and 2-level surgery, P = 0.029 and P = 0.032, respectively. A logistic regression model showed a stronger association to type of implant than to number of surgical levels. Duration of surgery was highly associated to number of surgical levels but did not differ significantly between types of implant. CONCLUSION: Long-term postoperative dysphagia could be explained by bulk of implant or decreased motion in the cervical spine. However, it is doubtful if differences between the groups in this study can be interpreted as a clinically important difference. LEVEL OF EVIDENCE: 2.

The Dysphagia Short Questionnaire: an instrument for evaluation of dysphagia: a validation study with 12 months' follow-up after anterior cervical spine surgery.

STUDY DESIGN: Prospective clinical validation study of questionnaire to assess dysphagia. OBJECTIVE: To test validity and reliability of Dysphagia Short Questionnaire (DSQ), and also to determine levels of dysphagia over time after anterior cervical spine surgery (ACSS). SUMMARY OF BACKGROUND DATA: Dysphagia is common after ACSS but reports on the incidence vary widely between 1% and 79%, indicating an evaluation problem. Several tools for evaluation of dysphagia exist but common features are that they are cumbersome to use and usually are designed for patients with neurological or malignant diseases in the neck region. Others are not validated, for example, the Bazaz score. There is, thus, a need for a more adapted tool to evaluate dysphagia in patients undergoing ACSS. METHODS: The DSQ was constructed in collaboration with a group of ear-nose-and-throat specialists. In a first validation study, 45 patients with stationary dysphagia for various reasons completed the DSQ twice 2 weeks apart, the M.D. Anderson Dysphagia Inventory (MDADI), the Bazaz score, and a quality-of-life score, the EQ-5D. To evaluate the utility of the DSQ, a second validation study was performed, where 111 subjects undergoing ACSS for degenerative disk disease completed the form preoperatively and at 4 weeks, 3 months, and 1 year after surgery. RESULTS: In the first study, the DSQ correlated to MDADI (r = 0.59) and showed good reproducibility. The Bazaz score did not correlate to the DSQ, the MDADI, or the EQ-5 D. In the second study, dysphagia was present in a few patients already preoperatively. At 4 weeks, 85% of the patients reported dysphagia. The level had dropped significantly at 3 months and had returned to baseline levels at 1 year. CONCLUSION: We consider the DSQ to be a validated tool for the assessment of dysphagia in ACSS patients. Dysphagia after ACSS for cervical spondylosis is common but the symptoms on a group level are not very severe and are also temporary.