Translation of the Neck Disability Index and validation of the Greek version in a sample of neck pain patients

Background  

Neck pain is a highly prevalent condition resulting in major disability. Standard scales for measuring disability in patients with neck pain have a pivotal role in research and clinical settings. The Neck Disability Index (NDI) is a valid and reliable tool, designed to measure disability in activities of daily living due to neck pain. The purpose of our study was the translation and validation of the NDI in a Greek primary care population with neck complaints.     

The normative score and the cut-off value of the Oswestry Disability Index (ODI)

Purpose

The Oswestry Disability Index (ODI) is one of the most common scoring systems used for patients with low back pain (LBP). Although the normative score of the ODI was reported to be 10.19 in a review article, no study has calculated the normative score after adjusting the value based on the age distribution. In addition, none of the previous studies has estimated the cut-off value which separates LBP with disability from LBP without disability. The purpose of this study was to estimate the normative score by adjusting the data for age distribution in Japan, and to determine the cut-off value which separates LBP with disability from LBP without disability.

Methods

We conducted an internet survey on LBP using the Japanese version of the ODQ. A total of 1,200 respondents, composed of 100 males and 100 females in each age group (from the 20s to 70s), participated in this study. We also asked them to provide information about their backgrounds. We estimated the normative score after correcting for the age distribution of Japan. We also estimated the ODI of those with or without disability, the factors associated with the ODI, and the cut-off value which separates LBP with disability from LBP without disability.

Results

The participants’ backgrounds were similar to the national survey. The normative score of the ODI was estimated at 8.73. The ODI of the LBP with disability group was 22.07. Those with sciatica and obese subjects showed higher ODI than those without. The optimal cut-off value was estimated to be 12.

Conclusions

We defined the normative score and the cut-off value of the ODI.     

Neck Disability Index,short form-36 physical component summary,and pain scales for neck and arm pain: the minimum clinically important difference and substantial clinical benefit after cervical spine fusion

Background ContextThe Neck Disability Index (NDI), the short form-36 (SF-36) physical component summary (PCS), and pain scales for arm and neck pain are increasingly used to evaluate treatment effectiveness after cervical spine surgery. The minimum clinically important difference (MCID) is a threshold of improvement that is clinically relevant to the patient. However, the true goal is to provide the patient with a substantial clinical benefit (SCB).PurposeThis study determines the MCID and SCB using common anchor-based methods for NDI, PCS, and pain scales for arm and neck pain in patients undergoing cervical spine fusion for degenerative disorders.Study Design/SettingThe study setting is a longitudinal cohort in a multisurgeon spine specialty clinic.Patient sampleThe sample comprises 505 patients who underwent a cervical fusion for degenerative spine conditions and who have prospectively collected outcome scores with a minimum 1-year follow-up.Outcome MeasuresThe outcome measures of the study were NDI, SF-36, and numeric rating scales for arm and neck pain.MethodsThe MCID and SCB values for NDI, PCS, and pain scales for arm and neck pain were determined using receiver operating characteristic (ROC) curve analysis with the Health Transition Item of the SF-36 as an anchor. The Health Transition Item asks a patient “Compared to one year ago, how would you rate your health in general now?” with answers ranging from “Much Better,” “Somewhat Better,” “About the Same,” “Somewhat Worse,” to “Much Worse.” An ROC curve was constructed for each measure. The ROC curve–derived MCID was the change score with equal sensitivity and specificity to distinguish the “Somewhat Better” from the “About the Same” patients. The ROC curve–derived SCB was the change score with equal sensitivity and specificity to distinguish the “Much Better” from the “Somewhat Better” patients. Distribution-based methods including the standard error of the mean and the minimum detectable change were also used to calculate MCID.ResultsThe calculated MCID is 7.5 for the NDI, 4.1 for SF-36 PCS, and 2.5 for arm and neck pain. The calculated SCB is 9.5 for the NDI, 6.5 for SF-36 PCS, and 3.5 for arm and neck pain.ConclusionsPatients with an eight-point decrease in NDI, a 4.1-point increase in PCS, and a three-point decrease in arm or neck pain can detect a minimally clinically important change. Patients with a 10-point decrease in NDI, a 6.5-point increase in PCS, and a four-point decrease in arm or neck pain can detect an SCB after cervical spine fusion.     

Reliability and Validity of Cross Culturally Adapted Punjabi Version of NDI (NDI-P) in Patients with Neck Pain: A Psychometric Analysis

BackgroundNeck disability index (NDI) is one of the commonest patient-reported outcome measures used to evaluate disability related to neck pain. Its application to non-English-speaking Punjabi population is limited as a validated and cross-culturally adapted Punjabi version of NDI is not available. The purpose of the study was to analyze the psychometric properties of Punjabi version of neck disability index (NDI-P) in patients with neck pain.Materials and MethodsThe translation and cross-cultural adaptation of Punjabi version of NDI was done according to well-recommended guidelines. The pre-final version was tested on a set of 15 patients and suitable modifications were made. The final version was administered to 100 patients with neck pain of more than 2 weeks duration. Psychometric properties comprising internal consistency, test–re-test reliability, construct validity and factorial structure of the questionnaire were determined.ResultsThe developed NDI-P showed excellent internal consistency (Chronbach alpha of NDI-P is 0.87), test–re-test reliability (ICC 0.840) and construct validity (Spearman correlation coefficient with VAS 0.547). Factor analysis proved the questionnaire to be having a 2-factor structure with a total variance of 56.58%.ConclusionNDI (P) is a reliable and valid instrument for measurement of disability related to neck pain in Punjabi population. It can be used both in research and clinical care settings in future.Electronic supplementary materialThe online version of this article (10.1007/s43465-020-00280-7) contains supplementary material, which is available to authorized users.     

A descriptive analysis of disorders in patients 17 years following motor vehicle accidents

Whiplash-associated disorders (WAD) are described and analysed 17 years after involvement in a motor vehicle accident. A self-report questionnaire was mailed to 121 patients registered at emergency departments in Gothenburg in 1983 because of neck complaints following a car collision. The questionnaire contained items on symptoms referred to WAD, treatment, work disability, involvement in settlement of claims, medical disability and the Neck Disability Index (NDI). Of the 121 patients, 108 (89%) chose to participate in the present study. Fifty-nine (55%) had residual disorders referable to the original accident. Neck pain, radiating pain and headache were the most common symptoms. One-third of the patients with residual symptoms suffered from work disability, compared to 6% in the group of patients without residual disorders. All 25 patients who had reached a final claim settlement (42%) had a poor outcome, and 15 of the claiming patients had been assigned a medical disability ranging from 5 to 30%. Patients with WAD reported a significantly higher score on the NDI than those without residual disorders. There was no significant correlation between the patients' degree of medical disability and the scores on the NDI. The results of the study show that approximately half of the patients with neck complaints following motor vehicle accidents in Gothenburg in 1983 suffered frequent residual symptoms 17 years after the accident, mostly comprising neck pain, radiating pain, and headache. The residual disorders contributed to the patients' overall disability.     

Neck pain and disability following motor vehicle accidents—a cohort study

The primary aim of the study was to compare the prevalence of neck pain and disability in a group exposed to motor vehicle accidents (MVAs) with those in the general population. The secondary aim was to assess the prevalence of a past history of exposure to an MVA with sequelae of neck pain in the general population. The exposed group consisted of 121 patients with neck complaints following an MVA in 1983. The control group, consisting of 1,491 subjects, was randomly selected, with attention to the distribution of age and gender in the exposed group. A neck-pain questionnaire was mailed to the subjects. In the control group, it included enquiry about a history of exposure to an MVA with sequelae of neck pain. The Neck Disability Index (NDI) was used to assess neck-related disability. In the exposed group 108 subjects (89%) responded, and in the control group 931 (62%) did. Seventeen years after the MVA, 59 subjects (55%) reported neck pain in the exposed group, with no gender differences. In the control group 270 (29%) reported neck pain with a higher frequency among women (34%) than men (19%) (p<0.01). There was a significant difference between the exposed group and the control group regarding the occurrence of neck pain (p<0.001). In the control group 34% recalled a history of an MVA, among whom one-third reported neck pain in connection with the accident and 28% had persistent neck pain referable to the accident. The exposed group scored significantly higher on the NDI (p<0.001) and reported significantly higher neck pain intensity than did the control group (p<0.001). In conclusion, a past history of exposure to an MVA with sequelae of neck pain appears to have a substantial impact on future persistent neck pain and associated disability.     

Responsiveness of the Neck Disability Index in patients with mechanical neck disorders

PurposeReport the test-retest reliability, construct validity, minimum clinically important difference (MCID), and minimal detectable change (MDC) for the Neck Disability Index (NDI).Study design/settingCohort study of patients presenting to outpatient physical therapy clinics.Patient sampleNinety-one subjects with a primary complaint of neck pain, with or without concomitant upper extremity (UE) symptoms, who were participants in a randomized clinical trial.Outcome MeasuresNDI and the 15-point Global Rating of Change (GRC) self-report measures.MethodsAll subjects completed the NDI at baseline and at a 3-week follow-up. Additionally, subjects completed the GRC scale, which was used to dichotomize patients into improved or stable groups. Changes in the NDI were used to assess test-retest reliability, construct validity, MCID, and MDC.ResultsTest-retest reliability was moderate for the NDI (intraclass correlation coefficient, 0.64; 95% confidence interval, 0.19–0.84). For the NDI, the MCID was 7.5 points and the MDC was 10.2 points.ConclusionsThe NDI appears to demonstrate adequate responsiveness based on statistical reference criteria when used in a sample that approximates the high percentage of patients with neck pain and concomitant UE referred symptoms. Because the MCID is within the bounds of measurement error, a 10-point change (the MDC) should be used as the MCID.     

Biopsychosocial sequelae and recovery trajectories from whiplash injury following a motor vehicle collision

BACKGROUND CONTEXTFive out of 10 injured in a motor vehicle collision (MVC) will develop persistent pain and disability. It is unclear if prolonged symptoms are related to peritraumatic pain/disability, psychological distress, muscle fat, lower extremity weakness.PURPOSETo test if widespread muscle fat infiltration (MFI) was (1) unique to those with poor recovery, (2) present in the peritraumatic stage, (3) related to known risk factors.STUDY DESIGN/SETTINGA cohort study, single-center academic hospital.PATIENT SAMPLESA total of 97 men and women (age 18–65) presenting to an urban academic emergency medicine department following MVC, but not requiring inpatient hospitalization.PRIMARY OUTCOME MEASURENeck disability at 12-months.METHODSParticipants underwent magnetic resonance imaging (MRI) to quantify neck and lower extremity MFI, completed questionnaires on pain/disability and psychological distress (< 1-week, 2-weeks, 3-, and 12-months) and underwent maximum volitional torque testing of their lower extremities (2-weeks, 3-, and 12-months). Percentage score on the Neck Disability Index at 12-months was used for a model of (1) Recovered (0%–8%), (2) Mild (10%–28%), and (3) Moderate/Severe (≥ 30%). This model was adjusted for BMI and age.RESULTSSignificant differences for neck MFI were revealed, with the Recovered group having significantly lower neck MFI than the Mild and Moderate/Severe groups at all time points. The Mild group had significantly more leg MFI at 12-months (p=.02) than the Recovered group. There were no other significant differences at any other time point. Lower extremity torques revealed no group differences. The Traumatic Injury Distress Scale (TIDS) and MFI of the neck at 1-week postinjury significantly predicted NDI score at 12-months.CONCLUSIONSHigher neck MFI and distress may represent a risk factor though it is unclear whether this is a pre-existing phenotype or result of the trauma.Trial RegistrationClinicalTrials.gov Identifier: NCT02157038.     

Predictors of failure to achieve minimal clinical important difference for pain and disability after mechanical diagnosis and therapy (MDT)-based multimodal rehabilitation for neck pain: a retrospective analysis of 4998 patients

Purpose

To determine predictors of failure to achieve minimal clinical important difference (MCID) for pain and disability at discharge after mechanical diagnosis and therapy (MDT)-based multimodal rehabilitation for neck pain (NP).

Methods

Pre- and post-treatment numerical pain rating scale (NPRS) and neck disability index (NDI) in patients with mechanical NP were analysed in this retrospective study. Multivariate analysis was performed to investigate the effect of covariates such as age, gender, lifestyle, body mass index, presentation, diabetes, osteoporosis, response to repeated movement testing, treatment sessions, compliance rate, and pre-treatment NPRS and NDI scores on failure to achieve MCID of ≥ 30% for NPRS and NDI scores post-treatment.

Results

In the 4998 patients analysed for this study, 7% and 14.5% of patients failed to achieve MCID for NPRS and NDI scores, respectively, at the end of treatment. Age > 70 years, diabetes, osteoporosis, partial or non-response to repeated movements, lesser treatment sessions, and lower compliance rate were associated with increased risk for failure to achieve MCID for NPRS and NDI scores. A higher pre-treatment NDI score was associated with failure to achieve MCID for NPRS score, whereas lower pre-treatment NPRS and NDI scores were associated with failure to achieve MCID for NDI score.

Conclusion

Although MDT-based multimodal rehabilitation helped to achieve significant reduction in pain and disability in mechanical NP, several baseline risk factors were associated with failure to achieve MCID for pain and disability after treatment. Identifying and modifying these factors as part of rehabilitation treatment may help to achieve better outcomes in mechanical NP.

     

Cross-cultural adaptation of the Neck Disability Index and Copenhagen Neck Functional Disability Scale for patients with neck pain due to degenerative and discopathic disorders. Psychometric properties of the Polish versions

Background  

Even though there are several region-specific functional outcome questionnaires measuring neck disorders that have been developed in English-speaking countries, no Polish version has ever been validated. The purpose of our study was to translate, culturally adapt and validate the Neck Disability Index (NDI) and Copenhagen Neck Functional Disability Scale (CDS) for Polish-speaking patients with neck pain.     

Neck and back pain specific outcome assessment questionnaires in the Spanish language: a systematic literature review

Background contextAccurate measurement of functional improvement in clinical practice is becoming increasingly recognized as essential in demonstrating whether patients are deriving meaningful benefit from care. Several simple questionnaires have been developed for this purpose. The majority of these have been developed in English. In North America, there is a growing need for clinical tools, including outcome assessment tools that are available in the Spanish language.PurposeThe purpose of this study was to systematically review the literature regarding spine-specific outcome assessment questionnaires that are available in Spanish and to examine the evidence on their clinical utility.Study designSystematic review.MethodsThe Medline, CINAHL, Embase, and MANTIS databases were searched for any studies on the topic of outcome assessment questionnaires in the Spanish language. Relevant articles were reviewed, and the data on reliability, validity, time to completion, and any other properties of the questionnaire was extracted.ResultsThe search strategy identified 287 articles, of which 10 were deemed relevant. With regard to neck pain, data were found regarding Spanish translations of the Northwick Park Neck Pain Questionnaire, Neck Disability Index (NDI), and Core Outcome Measure for neck pain. With regard to low back pain, data were found regarding Spanish translations of the Oswestry Low Back Pain Disability Index (ODI), Roland Morris Disability Questionnaire (RMQ), and the North American Spine Society—American Academy of Orthopedic Surgeons questionnaire.ConclusionsSeveral reliable and valid outcome assessment questionnaires are available in the Spanish language. All were originally developed in English. It appears from the data reviewed that the most useful instruments are the NDI for neck pain patients and the ODI and RMQ for low back pain patients. The current trend is for the development of culturally adapted versions of these questionnaires that are specific to a particular country or region.     

Favorable prognosis with nonsurgical management of type III acute odontoid fractures: a consecutive series of 212 patients

BACKGROUND CONTEXTThe recommended primary treatment for type III odontoid fractures (OFx) is external immobilization, except for patients having major displacement of the odontoid fragment. The bony fusion rate of type III OFx has been reported to be >85%. High compliance to treatment recommendations is favorable only if the treatment leads to a good outcome.PURPOSEThe primary aim of this study was to determine the long-term outcome after conservative and surgical treatment of type III OFx and to reaffirm that primary external immobilization is the best treatment for most type III fractures.STUDY DESIGN/SETTINGRetrospective study based on a prospective database.PATIENT SAMPLETwo hundred twelve consecutive patients with type III OFx treated at Oslo University Hospital over an 8-year period (2009–2017).OUTCOME MEASURESLong-term rates of bony fusion, crossover from primary conservative treatment to surgical fixation, new onset spinal cord injury (SCI), severe persistent neck pain (visual analogue scale - VAS), and persistent disability measured with Neck Disability index (NDI).METHODSThe present study was based on data extracted from our quality control database for acute cervical spine fractures from a general population. During the years 2018 to 2019 long-term follow-up of alive patients was performed (median follow-up time was 38.0 months; range 3.0–108.0 months). The follow-up included neurological examination, radiological examination and scoring of bony fusion status, crossover from primary conservative treatment to surgical fixation, new onset SCI, neck pain, and Neck Disability Index (NDI score).RESULTSIn this consecutive series of 212 patients with type III acute OFx, median patient age was 72 years, 56% had severe preinjury comorbidities (ASA score ≥3) and 22% lived dependently. Severe comorbidities and dependent living were significantly associated with increasing age (p<.001). The trauma mechanism was fall injury in 82%. The median age of patients injured by falls was significantly higher than in patients with a nonfall injury (p<.001). At the time of diagnosis, 4% had an OFx related SCI. Primary treatment was external immobilization alone in 95.3% and open surgical fixation in 4.7%. Patients treated with primary external immobilization alone presented with significantly less translation of the odontoid fragment (p<.001) and less angulation of the odontoid fragment (p=.025) than patients treated with primary surgery. Subsequent crossover to surgical fixation was performed in 5.4%. At long-term follow-up, 95.7% of patients had bony fusion of the OFx, 80.5% had minimal/no neck pain, and none developed new onset SCI. There was no significant difference in long-term follow-up VAS (p=.444) or NDI (p=.562) between the primary external immobilization group and the primary surgical group.CONCLUSIONThis study reaffirms that nonsurgical treatment remains the preferable option in the majority of patients with type III OFx.     

The association between neck pain, the Neck Disability Index and cervical ranges of motion: a narrative review

Background:

The Neck Disability Index (NDI) and Cervical Ranges of Motion (CROM) are measurement tools that are used for neck pain patients.

Objective:

To review the literature to determine how the NDI is associated with neck pain and CROM outcomes.

Methods:

Computer based searches of 5 databases were performed and supplemented by internet and hand searching of article references and “related citations.”

Results:

The search yielded 23 studies that met the inclusion and exclusion criteria and these were summarized into four categories: NDI, NDI and other questionnaires, whiplash and NDI and cervical range of motion and NDI. The NDI was shown to be a well validated and reliable self-reported questionnaire, especially when compared to other questionnaires, in both neck pain and whiplash (WAD) patients. There are very few studies that discuss the NDI and cervical range of motion.

Conclusion:

This review outlines the strength of the NDI as a self-reported neck disability questionnaire, but also demonstrates a need for further research to explore the association between the NDI, neck pain and cervical ranges of motion.     

Outcomes of cervical disc replacement in patients with neck pain greater than arm pain

BACKGROUND CONTEXTAlthough anterior cervical discectomy and fusion is believed to positively impact a patient's radicular symptoms as well as axial neck pain, the outcomes of cervical disc replacement (CDR) with regards to neck pain specifically have not been established.PURPOSEPrimary: to assess clinical improvement following CDR in patients with neck pain greater than arm pain. Secondary: to compare the clinical outcomes between patients undergoing CDR for predominant neck pain (pNP), predominant arm pain (pAP), and equal neck and arm pain (ENAP).STUDY DESIGNRetrospective review of prospectively collected data.PATIENT SAMPLEPatients who had undergone one- or two-level CDR for the treatment of degenerative cervical pathology and had a minimum of 6-month follow-up were included and stratified into three cohorts based on their predominant location of pain: pNP, pAP, and ENAP.OUTCOME MEASURESPatient-reported outcomes: Neck Disability Index (NDI), Visual Analog Scale (VAS) neck and arm, Short Form 12-Item Physical Health Score (SF12-PHS), Short Form 12-Item Mental Health Score (SF12-MHS), minimal clinically important difference (MCID).METHODSChanges in Patient-reported outcomes from preoperative values to early (<6 months) and late (≥6 months) postoperative timepoints were analyzed within each of the three groups. The percentage of patients achieving MCID was also evaluated.RESULTSOne hundred twenty-five patients (52 pNP, 30 pAP, 43 ENAP) were included. The pNP cohort demonstrated significant improvements in early and late NDI and VAS-Neck, early SF-12 MCS, and late SF-12 PCS. The pAP and ENAP cohorts demonstrated significant improvements in all PROMs, including NDI, VAS-Neck, VAS-Arm, SF-12 PCS, and SF-12 MCS, at both the early and late timepoints. No statistically significant differences were found in the MCID achievement rates for NDI, VAS-Neck, SF-12 PCS, and SF-12 MCS at the late timepoint amongst the three groups.CONCLUSIONSCDR leads to comparable improvement in neck pain and disability in patients presenting with neck pain greater than arm pain and meeting specific clinical and radiographic criteria.     

Predictive factors for the outcome of anterior cervical decompression and fusion

In a prospective study, 103 patients were randomised to anterior cervical decompression and fusion (ACDF) with a cervical carbon-fibre intervertebral fusion cage or the Cloward procedure. Preoperative background variables, active range of neck motion, handgrip strength, radiological evaluation and subjective variables were used in a multiple regression model to find the strongest predictors of postoperative outcome as measured by current pain intensity and the Neck Disability Index (NDI). Male sex, greater kyphosis at the level operated on, non-smoking, a greater neck mobility in right rotation, low disability on NDI, and older age were predictors of pain reduction and explained 30% of current pain intensity at follow-up. Higher educational level, non-smoking, greater kyphosis at the level operated on, a greater flexion mobility, greater right handgrip strength and lower current pain intensity were predictors of improvement, and explained 28% of the postoperative outcome on NDI. The most important predictor for postoperative pain intensity was the magnitude of the preoperative kyphosis. Preoperative pain intensity was the most important predictor for improved NDI. At follow-up about 70% of the patients still had deficit based on current pain intensity and NDI, and 44% had remaining dysfunction based on Odom's criteria. In conclusion, the multivariate analysis shows that male sex, non-smoking, greater segmental kyphosis and a low pain and disability level are preoperative predictors of a good outcome in ACDF. In addition, the study suggests the importance of other predictive variables than those studied for the outcome of ACDF.     

Anterior cervical discectomy and fusion in young adults leads to favorable outcome in long-term follow-up

Background ContextAnterior cervical discectomy and fusion (ACDF) procedures is thought to lead to accelerated degeneration of the adjacent cervical discs and in some cases can be symptomatic (adjacent segment disease, or ASD). The occurrence of ASD is of particular interest when treating young individuals, as the cumulative disease burden may become increasingly significant during their expectedly long lifetime. However, the overall impact of a surgical intervention on the lifetime prognosis of ASD remains unclear.PurposeOur goal was to study the long-term outcomes of ACDF surgery among those members of the young adult population who have been operated on between the ages of 18 and 40.Study DesignRetrospective study.Patient SampleAll patients between 18 and 40 years of age at the time of surgery who underwent ACDF due to degenerative cervical disorders at Helsinki University Hospital between the years of 1990 and 2005 (476 patients).Outcome MeasuresCervical reoperation rate, satisfaction with the surgery, employment status, Neck Disability Index (NDI).MethodsWe retrospectively analyzed the medical records of all patients between 18 and 40 years of age at the time of surgery who underwent ACDF due to degenerative cervical disorders at Helsinki University Hospital between the years of 1990 and 2005. We sent questionnaires to all available patients at the end of the follow-up (median 17.5 years) to assess their current neck symptoms, general situations, and levels of satisfaction with the surgery. Furthermore, we compared the results for different types of ACDF surgeries (ie, discectomy only vs. synthetic cage or bone autograft implantation for fusion) in propensity-score-matched groups.ResultsOf the 476 patients who were included in the study, surgery was performed in 72% of the cases due to intervertebral disc herniation and in 28% due to spondylotic changes. The total reoperation rate during the entire follow-up (median 17.5 years) was 24%, and 19.5% if early reoperations (<28 days from index surgery) were excluded. At 10 years postsurgery, the total reoperation rate was 16.8% and 12.8% with early reoperations excluded. The probability of surgery for adjacent level disease was 10.3% at 10 years and 16.8% for the duration of the entire follow-up, with the annual incidence rate of 1.1% for those with ASD requiring surgery. Statistically significant risk factors leading to the need for further cervical surgery included central spinal cord compression and smoking at the time of the index operation. After propensity score matching, there was no significant difference found between the outcomes of different types of surgery. A total of 443 patients were still able to be contacted 12–28 years after the surgery. Of the 281 patients responding to the questionnaires, 92% were still satisfied with the results. With respect to employment, 67% of patients were working, 7% were unemployed, and 7% were on disability due to cervical problems. The median NDI score was 12%, with 56% of patients having an NDI score lower than 15%; it has been suggested that this latter NDI score serves as a cut-off value for significant neck morbidity. The NDI scores were significantly higher among female patients, patients with spondylosis, and patients having undergone further cervical surgeries during the follow-up.ConclusionsLong-term satisfaction with the surgery was very high, and the employment rate among patients resembled that of the general population in Finland. Thus, the long-term prognosis after having ACDF surgery at a younger age seems to be good, even though nearly half of the patients experienced some persistent neck symptoms later in life.     

Confirmatory factory analysis of the Neck Disability Index in a general problematic neck population indicates a one-factor model

Background contextThe Neck Disability Index frequently is used to measure outcomes of the neck. The statistical rigor of the Neck Disability Index has been assessed with conflicting outcomes. To date, Confirmatory Factor Analysis of the Neck Disability Index has not been reported for a suitably large population study. Because the Neck Disability Index is not a condition-specific measure of neck function, initial Confirmatory Factor Analysis should consider problematic neck patients as a homogenous group.PurposeWe sought to analyze the factor structure of the Neck Disability Index through Confirmatory Factor Analysis in a symptomatic, homogeneous, neck population, with respect to pooled populations and gender subgroups.Study designThis was a secondary analysis of pooled data.Patient sampleA total of 1,278 symptomatic neck patients (67.5% female, median age 41 years), 803 nonspecific and 475 with whiplash-associated disorder.Outcome measuresThe Neck Disability Index was used to measure outcomes.MethodsWe analyzed pooled baseline data from six independent studies of patients with neck problems who completed Neck Disability Index questionnaires at baseline. The Confirmatory Factor Analysis was considered in three scenarios: the full sample and separate sexes. Models were compared empirically for best fit.ResultsTwo-factor models have good psychometric properties across both the pooled and sex subgroups. However, according to these analyses, the one-factor solution is preferable from both a statistical perspective and parsimony. The two-factor model was close to significant for the male subgroup (p<.07) where questions separated into constructs of mental function (pain, reading headaches and concentration) and physical function (personal care, lifting, work, driving, sleep, and recreation).ConclusionsThe Neck Disability Index demonstrated a one-factor structure when analyzed by Confirmatory Factor Analysis in a pooled, homogenous sample of neck problem patients. However, a two-factor model did approach significance for male subjects where questions separated into constructs of mental and physical function. Further investigations in different conditions, subgroup and sex-specific populations are warranted.     

Detecting relevant changes and responsiveness of Neck Pain and Disability Scale and Neck Disability Index

Purpose

To investigate relevant change on the Neck Pain and Disability Scale (NPAD) and Neck Disability Index (NDI) and which questionnaire is the most responsive in patients with non-specific chronic neck pain (CNP).

Methods

Seventy-six patients with non-specific CNP in an outpatient tertiary rehabilitation setting were dichotomized into “improved” and “stable” based on global perceived effect (GPE) scores. To investigate relevant change minimal detectable change (MDC) and minimal important change (MIC) with the receiver operator characteristic (ROC) cut-off point were assessed. Comparison of responsiveness was performed using areas under the ROC curve (AUC) and correlations between change scores of NPAD and NDI, and GPE.

Results

MDC and MIC on NPAD (scale 0–100) were 31.7 and 11.5 points, respectively. MDC and MIC on NDI (scale 0–50) were 8.4 and 3.5 points, respectively. Changes should exceed this MDC or MIC cut-off to be interpreted as relevant. AUC was 0.75 for both NPAD and NDI. Correlations between change scores of NPAD and NDI, and GPE were, respectively, 0.48 (95 % CI 0.29–0.64) and 0.49 (95 % CI 0.30–0.64).

Conclusions

Relevant change on both NPAD and NDI assessed with MDC and MIC resulted in different cut-offs and consequently with different amounts of certainty that the patient is improved. Responsiveness of NPAD and NDI was similar.     

Development of a clinical prediction rule to identify patients with neck pain who are likely to benefit from home-based mechanical cervical traction

The objective of the study was to identify the population of patients with neck pain who improved with home-based mechanical cervical traction (HMCT). A prospective cohort study was conducted in a physical therapy clinic at a local hospital. Patients with neck pain referred to the clinic for physical therapy were included in the study. A HMCT program was given to participants for 2 weeks. The patient’s demographic data, Numerical Pain Scale (NPS) score, Neck Disability Index (NDI) and Fear-Avoidance Beliefs Questionnaire score were collected, and standard physical examination of the cervical spine was conducted before intervention. The NPS score, NDI and a global rating of perceived improvement were collected after the intervention was completed. A total of 103 patients participated in the study and 47 had a positive response to HMCT. A clinical prediction rule with four variables (Fear-Avoidance Beliefs Work Subscale score < 13, pre-intervention pain intensity ≥ 7/10, positive cervical distraction test and pain below shoulder) was identified. With satisfaction of at least three out of four variables (positive likelihood ratio = 4.77), the intervention’s success rate increased from 45.6% to over 80%. It appears that patients with neck pain who are likely to respond to HMCT may be identified.     

Development of the Neck Pain and Disability Scale. Item analysis, face, and criterion-related validity.

STUDY DESIGN: The development and testing of a new comprehensive measure of neck pain and disability, the Neck Pain and Disability Scale. OBJECTIVES: To provide an initial evaluation of the Neck Pain and Disability Scale's reliability and validity. SUMMARY OF BACKGROUND DATA: Although several measures exist for generalized pain and disability, none is specific for neck pain. More specific measurements should improve assessment of treatments and clinical research aimed at cervical pain syndromes. METHODS: The Neck Pain and Disability Scale was designed using the Million Visual Analogue Scale as a template and consists of 20 items that assess neck pain. In this study, 100 patients with neck pain, 52 patients with lower back and leg pain, and 27 pain-free volunteers were rated by the Neck Pain and Disability Scale. In addition, a subset of the 47 patients with neck pain were rated by several other established psychometric instruments. RESULTS: An item analysis showed a high degree of internal consistency among the 20 items on the Neck Pain and Disability Scale (r = 0.93), and face validity was established by comparing patients who had neck pain as well as lower back and leg pain with a pain-free group. The Neck Pain and Disability Scale scores correlated with the Oswestry Disability Questionnaire, the Pain Disability Index, and psychological measures of depression and neuroticism. CONCLUSIONS: The results suggest a highly reliable instrument for evaluating neck pain with at least four underlying dimensions. Further work to address the predictive validity of this new tool are under way.