Degenerative cervical myelopathy: establishing severity thresholds for neuromotor dysfunction in the aging spine using the NIH Toolbox Assessment Scale

Degenerative cervical myelopathy (DCM) is a leading cause of age-related non-traumatic spinal cord disorders resulting from chronic degeneration of the cervical spine. While traditional clinical assessments rely on patient-reported measures, this study used the NIH Toolbox Motor Battery (NIHTBm) as an objective, quantitative measure to determine DCM severity. The objective is to define NIHTBm cutoff values that can accurately classify the severity of DCM neuromotor dysfunction. A case-controlled pilot study of patients with DCM and age-matched controls. The focus was an in-depth quantitative motor assessment using the NIHTBm to understand the severity of neuromotor deficits due to degenerative spine disease. Motor assessments, dexterity, grip strength, balance, and gait speed were measured in 45 DCM patients and 37 age-matched healthy subjects (HC). Receiver operating curve (ROC) analysis determined cutoff values for mild and moderate-to-severe myelopathy which were validated by comparing motor assessment scores with disability scores. The ROC curves identified thresholds for mild dexterity impairment (T-score range 38.4 - 33.5, AUC 0.77), moderate-to-severe dexterity impairment (< 33.5, AUC 0.70), mild grip strength impairment (47.4 - 32.0, AUC 0.80), moderate-to-severe grip strength impairment (< 32.0, AUC 0.75), mild balance impairment (36.4 - 33.0, AUC 0.61), and moderate-to-severe balance impairment (< 33.0, AUC 0.78). Mild gait speed impairment was defined as 0.78-0.6 m/sec (AUC 0.65), while moderate-to-severe gait speed impairment was < 0.6 m/sec (AUC 0.65). The NIHTB motor score cutoff points correlated negatively with the DCM neck disability index (NDI) and showed balance and dexterity measures as independent indicators of DCM dysfunction. The use of NIHTB allows for precise delineation of DCM severity by establishing cutoff values corresponding to mild and moderate-to-severe myelopathy. The use of NIHTB in DCM allows enhanced clinical precision, enabling clinicians to better pinpoint specific motor deficits in DCM and other neurological disorders with motor deficits, including stroke and traumatic brain injury (TBI). Furthermore, the utility of objective assessment, NIHTB, allows us to gain a better understanding of the heterogeneity of DCM, which will enhance treatment strategies. This study serves as a foundation for future research to facilitate the discovery of innovative treatment strategies for DCM and other neurological conditions.

Risk factors for failure to achieve minimal clinically important difference following cervical disc replacement

BACKGROUND CONTEXT

While cervical disc replacement (CDR) has been emerging as a reliable and efficacious treatment option for degenerative cervical spine pathology, not all patients undergoing CDR will achieve minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) postoperatively-risk factors for failure to achieve MCID in PROMs following CDR have not been established.

PURPOSE

To identify risk factors for failure to achieve MCID in Neck Disability Index (NDI, Visual Analog Scale (VAS) neck and arm following primary 1- or 2-level CDRs in the early and late postoperative periods.

STUDY DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

Patients who had undergone primary 1- or 2-level CDR for the treatment of degenerative cervical pathology at a single institution with a minimum follow-up of 6 weeks between 2017 and 2022.

OUTCOME MEASURES

Patient-reported outcomes: Neck disability index (NDI), Visual analog scale (VAS) neck and arm, MCID.

METHODS

Minimal clinically important difference achievement rates for NDI, VAS-Neck, and VAS-Arm within early (within 3 months) and late (6 months to 2 years) postoperative periods were assessed based on previously established thresholds. Multivariate logistic regressions were performed for each PROM and evaluation period, with failure to achieve MCID assigned as the outcome variable, to establish models to identify risk factors for failure to achieve MCID and predictors for achievement of MCID. Predictor variables included in the analyses featured demographics, comorbidities, diagnoses/symptoms, and perioperative characteristics.

RESULTS

A total of 154 patients met the inclusion criteria. The majority of patients achieved MCID for NDI, VAS-Neck, and VAS-Arm for both early and late postoperative periods-79% achieved MCID for at least one of the PROMs in the early postoperative period, while 80% achieved MCID for at least one of the PROMs in the late postoperative period. Predominant neck pain was identified as a risk factor for failure to achieve MCID for NDI in the early (OR: 3.13 [1.10-8.87], p-value: .032) and late (OR: 5.01 [1.31-19.12], p-value: .018) postoperative periods, and VAS-Arm for the late postoperative period (OR: 36.63 [3.78-354.56], p-value: .002). Myelopathy was identified as a risk factor for failure to achieve MCID for VAS-Neck in the early postoperative period (OR: 3.40 [1.08-10.66], p-value: .036). Anxiety was identified as a risk factor for failure to achieve MCID for VAS-Neck in the late postoperative period (OR: 6.51 [1.91-22.18], p-value: .003). CDR at levels C5C7 was identified as a risk factor for failure to achieve MCID in NDI for the late postoperative period (OR: 9.74 [1.43-66.34], p-value: .020).

CONCLUSIONS

Our study identified several risk factors for failure to achieve MCID in common PROMs following CDR including predominant neck pain, myelopathy, anxiety, and CDR at levels C5-C7. These findings may help inform the approach to counseling patients on outcomes of CDR as the evidence suggests that those with the risk factors above may not improve as reliably after CDR.

Comparison of pain relief of the cervical radiculopathy between high thoracic erector spinae plane block and cervical epidural injection

BACKGROUND

The high thoracic erector spinae plane block (ESPB) has been used for the management of chronic shoulder pain or arthroscopic shoulder surgery. No study has evaluated the analgesic efficacy of ESPB in patients with cervical radiculopathy although it is a favored and easy technique compared to neuraxial block. The purpose of this study was to compare the treatment outcome of cervical radiculopathy using high thoracic ESPB or cervical interlaminar epidural injection (CEPI).

METHODS

This study included 82 patients with neck and arm pain who received CEPI (CEPI group) using 4 ml of 0.1% ropivacaine or high thoracic ipsilateral ESPB (ESPB group) at the T2 or T3 level using 20 ml of 0.1% ropivacaine 20 ml. The degree of pain relief and disability were assessed using an 11-point numerical scale (NRS) and neck disability index (NDI), respectively.

RESULTS

The CEPI and ESPB groups demonstrated an equal number of patients with excellent pain relief (NRS reduction ≥ 50%). Significant reduction of NRS was found in both groups, and the effect of time was statistically significant in the groups (P < 0.001). The number of patients who showed an excellent improvement in NDI (NDI reduction ≥ 30%) was 20 (48.8%) and 22 (53.7%) in the CEPI and ESPB groups, respectively.

CONCLUSIONS

Both the CEPI and ESPB demonstrated significant relief in neck and arm pain with improvement in disability.

Pain and Depression Account for More Than One Half of the Neck Disability Variance Among Adult Women with Chiari I

OBJECTIVE

We sought to quantify the neck-related disability in adult women with Chiari malformation type I and identify the significantly related variables.

METHODS

A total of 70 variables were selected from the self-report history questionnaires (12 variables; n = 474), standardized scales (15 variables; n = 474), and morphometric data (43 variables; n = 293-474) of adult women with Chiari malformation type I. The variables were tested independently to identify those with a significant relationship to the Neck Disability Index (NDI; P < 0.00071) and those that might be associated with the NDI (P < 0.05). A forward selection regression model was constructed to identify the variables contributing unique variance to the NDI. In addition, a mediation analysis was performed to determine whether depression mediated the relationship between pain and disability.

RESULTS

Overall, 79.5% of the patients had scored at a moderate level of disability or higher. Independent testing identified 16 significant variables, including symptom duration, tonsillar position, and measures of psychological distress. The short-form McGill pain questionnaire-2 (r = 0.69; P < 0.00001) and CES-D scale for depression (r = 0.56; P < 0.00001) exhibited the highest correlations with the NDI. The forward selection regression model produced an R² of 0.6178. Pain and depression accounted for more than one half of the NDI variance.

CONCLUSIONS

We found that high levels of disability are common among adult women with Chiari malformation type I, independent of surgical status. Pain and depression were the primary factors related to this disability. Depression mediated the relationship between pain intensity and disability at a modest level (5%). Patients who had experienced symptoms for >2 years before diagnosis had had, on average, 77% higher NDI scores, highlighting the importance of a timely diagnosis.

Sex-related differential item functioning of neck disability index

PURPOSE

To investigate if the responses to the Neck Disability Index (NDI) may produce some differential item functioning (DIF) comparing men and women.

MATERIALS AND METHODS

Register-based study among patients undergoing cervical surgery. Item response theory (IRT) analysis including a model for detecting a DIF.

RESULTS

Of 338 patients, 171 (51%) were women and 167 (49%) were men. The mean age was 54.0 years. For most of the items, the average level of disability in a studied sample was associated with the middle point of the scale. The ability to distinguish people with different levels of disability was high or perfect for seven out of 10 items. While the DIF could be seen for all 10 items, only three items demonstrated statistically significant DIF - "pain intensity", "headaches" and "recreation". While the other seven items did not show statistically significant DIFs, better discrimination (steeper curves) for women could be graphically observed for "personal care", "lifting", "work", "driving" and "sleeping".

CONCLUSIONS

It seemed that the NDI may behave differently depending on the sex of respondents. Several items of the NDI may be more precise and more sensitive when detecting restrictions in functioning among women compared to men. This finding should be taken into account when using the NDI in research and clinical practice.Implications for RehabilitationWhile the Neck Disability Index have been found to be a reliable and valid scale, potential differences in its properties across different sexes have mostly remained uninvestigated.This study showed that the Neck Disability Index may behave differently depending on the sex of respondents.Several items of the Neck Disability Index were more precise and sensitive when detecting restrictions in functioning among women compared to men.This difference should be taken into account when using the NDI in research and clinical practice.

Patients with radiculopathy have worse baseline disability and greater improvements following anterior cervical discectomy and fusion compared to patients with myelopathy

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) is commonly performed in patients with radiculopathy and myelopathy. Although the goal of surgery in patients with radiculopathy is to improve function and reduce pain, patients with myelopathy undergo surgery to halt disease progression. Although the expectations between these preoperative diagnoses are generally understood to be disparate by spine surgeons, there is limited literature demonstrating their discordant outcomes.

PURPOSE

To compare improvements in patient reported outcome measures (PROMs) for patients undergoing ACDF for myelopathy or radiculopathy. Secondarily, we analyzed the proportion of patients who attain the minimum clinically important difference (MCID) postoperatively using thresholds derived from radiculopathy, myelopathy, and mixed cohort studies.

STUDY DESIGN/SETTING

Single institution retrospective cohort study PATIENT SAMPLE: Patients undergoing primary, elective ACDF with a preoperative diagnosis of radiculopathy or myelopathy and a complete set of preoperative and one-year postoperative PROMs.

OUTCOME MEASURES

Outcome measures included the following PROMs: Short-Form 12 Physical Component (PCS-12) and Mental Component (MCS-12) scores, the Visual Analog Scale (VAS) Arm score, and the Neck Disability Index (NDI). Hospital readmissions and revision surgery were also collected and evaluated.

METHODS

Patients undergoing an ACDF from 2014 to 2020 were identified and grouped based on preoperative diagnosis (radiculopathy or myelopathy). We utilized "general MCID" thresholds from a cohort of patients with degenerative spine conditions, and "specific MCID" thresholds generated from cohorts of patients with myelopathy or radiculopathy, respectively. Multivariate linear regressions were performed for delta (∆) PROMs and multivariate logistic regressions were performed for both general and specific MCID improvements.

RESULTS

A total of 798 patients met inclusion criteria. Patients with myelopathy had better baseline function and arm pain (MCS-12: 49.6 vs 47.6, p=.018; VAS Arm: 3.94 vs 6.02, p<.001; and NDI: 34.1 vs 41.9, p<.001), were older (p<.001), had more comorbidities (p=.014), more levels fused (p<.001), and had decreased improvement in PROMs following surgery compared to patients with radiculopathy (∆PCS-12: 4.76 vs 7.21, p=.006; ∆VAS Arm: -1.69 vs -3.70, p<.001; and ∆NDI: -11.94 vs -18.61, p<.001). On multivariate analysis, radiculopathy was an independent predictor of increased improvement in PCS-12 (β=2.10, p=.019), ∆NDI (β=-5.36, p<.001), and ∆VAS Arm (β=-1.93, p<.001). Radiculopathy patients were more likely to achieve general MCID improvements following surgery (NDI: Odds ratio (OR): 1.42, p=.035 and VAS Arm: OR: 2.98, p<.001), but there was no difference between patients with radiculopathy or myelopathy when using radiculopathy and myelopathy specific MCID thresholds (MCS-12: p=.113, PCS-12: p=.675, NDI: p=.108, and VAS Arm: p=.314).

CONCLUSIONS

Patients undergoing ACDF with myelopathy or radiculopathy represent two distinct patient populations with differing treatment indications and clinical outcomes. Compared to radiculopathy, patients with myelopathy have better baseline function, decreased improvement in PROMs, and are less likely to reach MCID using general threshold values, but there is no difference in the proportion reaching MCID when using specific threshold values.

LEVEL OF EVIDENCE

IRB.

A study from Swespine, the National Swedish spine register

PURPOSE

The Oswestry Disability Index (ODI) and the Neck Disability Index (NDI) scoring algorithms used by the Swedish spine register (Swespine) until April 2022 handled missing items somewhat differently than the original algorithms. The purpose of the current study was to evaluate possible differences in the ODI and NDI scores between the Swespine and the original scoring algorithms.

METHODS

Patients surgically treated for degenerative conditions of the lumbar or cervical spine between 2003-2019 (lumbar) and 2006-2019 (cervical) were identified in Swespine. Preoperative and 1-year postoperative ODI/NDI data were used to evaluate differences between the Swespine and the original ODI/NDI algorithms with adjustment for at most 1 or 2 missing items using mean imputation.

RESULTS

The preoperative as well as the 1-year postoperative ODI/NDI were approximately 1 unit out of 100 smaller for the Swespine algorithm, irrespective of adjustment model. The differences between preoperative and postoperative ODI/NDI scores were similar between the Swespine and the original scoring algorithms. There were occasional statistically significant differences between the preoperative-postoperative differences due to large sample sizes.

CONCLUSIONS

The Swespine algorithms, used until April 2022, underestimated the ODI and NDI by approximately 1 out of 100 units compared with the original algorithms. In addition, there were no statistically significant differences between the original algorithms when adjusting for at most 1 or 2 missing items. The algorithm has now been changed, also for historical data.

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

BACKGROUND CONTEXT

Although 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.

PURPOSE

Primary: 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 DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

Patients 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 MEASURES

Patient-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).

METHODS

Changes 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.

RESULTS

One 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.

CONCLUSIONS

CDR 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.

The association between different outcome measures and prognostic factors in patients with neck pain: a cohort study

Background

Health domains like pain, disability, and health-related quality of life are commonly used outcomes for musculoskeletal disorders. Most prognostic studies include only one outcome, and it is unknown if prognostic factors and models may be generic across different outcomes. The objectives of this study were to examine the correlation among commonly used outcomes for neck pain (pain intensity, disability, and health-related quality of life) and to explore how the predictive performance of a prognostic model differs across commonly used outcomes.

Methods

We conducted an observational prospective cohort study with data from patients with neck pain aged 18–84 years consulting Norwegian chiropractors. We used three different outcomes: pain intensity (Numeric Pain Rating Scale), the Neck Disability Index (NDI), and health-related quality of Life (EQ-5D). We assessed associations between change in outcome scores at 12-weeks follow-up with Pearson’s correlation coefficient. We used multivariable linear regression models to explore differences in explained variance and relationship between predictors and outcomes.

Results

The study sample included 1313 patients and 941 (72%) completed follow-up at 12 weeks. The strongest correlation was between NDI and EQ-5D (r = 0.57) while the weakest correlation was between EQ-5D and pain intensity (r = 0.39). The correlation between NDI and pain intensity was moderate (r = 0.53) In the final regression models, the explained variance ranged from adjusted R² of 0.26 to 0.60, highest with NDI and lowest with pain intensity as outcome. The predictive contributions of the included predictors were similar across outcomes. Among the investigated predictors, pain patterns and the baseline measure of the corresponding outcome measure contributed the most to explained variance across all outcomes.

Conclusions

The highest correlation was found between NDI and EQ-5D and the lowest with pain intensity. The same prognostic model showed highest predictive performance with NDI as outcome and poorest with pain intensity as outcome. These results suggest that we need more knowledge on the reasons for the differences in predictive performance variation across outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05558-5.

Functional outcomes in the management of cervicothoracic junction tuberculosis

Background

We analyzed the clinical and radiological parameters influencing functional outcomes and neurological recovery in patients with cervicothoracic junctional tuberculosis (TB).

Methods

This was a retrospective analysis of 16 cases of cervicothoracic junction (CTJ) spinal TB; 11 patients were managed operatively, while five were managed conservatively. Patients' outcomes were assessed at 1 month, 1 year, and yearly thereafter and included an analysis of multiple outcome scores, various radiographic parameters, and sensitivity or resistance to anti-tubercular therapy.

Results

Patients averaged 25.94 years of age, and typically had three-level vertebral involvement. They were followed for a mean duration of 24 months, and the duration of anti-tubercular therapy averaged 17 months. Patients demonstrated clinical improvement on Japanese Orthopedic Association score and Neck disability index (P < 0.005) starting from 1 month following initiation of treatment which continued in subsequent follow-up, along with change in radiological parameters consisting of mean segmental kyphotic angle from 18.98° to 15.13°, C2-C7 SVA from 16.13 mm to 22.61 mm, T1 slope from 22.80° to 14.66°, thoracic inlet angle from 75.35° to 63.25°, neck tilt from 51.81° to 48.33°, and cervical lordosis from 4.66° to -0.44° (P > 0.05) at the end of 1 year.

Conclusion

Tuberculous affection of the dynamic CTJ is a challenging scenario in clinical practice and its management involves consideration of disease extent, neurological status, and effort toward restoration of normal alignment of spine in sagittal and coronal plane to get favorable clinical outcomes.

The impact of mental health on outcome after anterior cervical discectomy: cohort study assessing the influence of mental health using predictive modelling

BACKGROUND

Depression and anxiety are common mental disorders among patients with chronic pain. It is hypothesised that patients suffering from these disorders benefit less from cervical spine surgery than mentally healthy patients. Therefore, this study aimed to quantify the effect of mental health status on functional outcome after anterior cervical discectomy in a post hoc analysis on RCT data.

METHODS

One hundred eight patients from the NECK trial, with radiculopathy due to a one-level herniated disc, underwent anterior cervical discectomy and were included into this analysis. Functional outcome was quantified using the Neck Disability Index (NDI), and mental health status was measured using the Hospital Anxiety and Depression Score (HADS) questionnaire. NDI differences were assessed using generalised estimated equations (GEE), crude means, a predictive linear mixed model (LMM) using baseline scores and over time with an explanatory LMM.

RESULTS

At baseline, 24% and 32% of patients were respectively depressed and anxious and had statistically significant and clinically relevant higher NDI scores during follow-up. However, in those patients in which the HADS returned to normal during follow-up, NDI values decreased comparably to the non-depression or non-anxiety cases. Those patients that demonstrated persisting high HADS values had convincingly worse NDI scores. A predictive LMM showed that combining baseline NDI and HADS scores was highly predictive of NDI during follow-up. The R shiny application enabled the effective, visual communication of results from the predictive LMM.

CONCLUSION

This study shows that mental health status and disability are strongly associated and provides insight into the size of the effect, as well as a way to use this relation to improve preoperative patient counselling. These findings give rise to the suggestion that incorporating mental health screening in the preoperative assessment of patients could help to adequately manage patients' expectations for functional recovery.

TRIAL REGISTRATION

Dutch Trial Register Number: NTR1289.

Criterion validation and interpretability of the Single Assessment Numerical Evaluation (SANE) of self-reported recovery in patients with neck pain

BACKGROUND

The SANE is a PROM of recovery, which may assist clinicians in clinical decision-making and discharge planning. The psychometric measurement properties of the SANE have yet to be determined for neck pain.

OBJECTIVES

Threefold objectives included: 1)determine the numerical threshold for the SANE at which patients with neck pain determine their symptoms are acceptable; 2)determine the association between scores for the NDI and VAS, with the SANE; 3)determine the average number of visits, costs and value associated with the management of neck pain.

DESIGN

Longitudinal repeated measures cohort design.

METHODS

Threshold measures for self-reported recovery with the SANE anchored to the PASS were examined using ROC. PCC determined the relationship between the VAS/pain and NDI raw/percentage change scores and the SANE at discharge. Descriptive statistics were used for number of visits and cost. Value was calculated as the proportion of change on the NDI and VAS/$100 US dollars spent.

RESULTS

57 subjects completed full observation. ROC analysis indicates a threshold value of 82.5%(Sn = 56.0, Sp = 85.7,+LR = 1.68,-LR = 0.29) on the SANE with an AUC of 0.820(95%CI = 0.638, 1.00). A weak correlation was found between raw NDI(r = 0.39 p < 0.05)/Pain(r = 0.45 p < 0.05) scores and the SANE with a moderate correlation between percent change scores of NDI(r = 0.52 p < 0.05)/PAIN(r = 0.54 p < 0.05) and the SANE. The value proposition indicated cost of care amounted to a 10.5% and 12.9%; improvement in the NDI and pain scores/$100 spent.

CONCLUSIONS

Patients reporting greater than 82.5% on the SANE are likely to find their present status acceptable and potentially stop seeking care.

The effect of two weeks of spinal manipulative therapy and home stretching exercises on pain and disability in patients with persistent or recurrent neck pain; a randomized controlled trial

Background

Recurrent or persistent neck pain affects a vast number of people globally, leading to reduced quality of life and high societal costs. Clinically, it is a difficult condition to manage, and treatment effect sizes are often moderate at best. Activity and manual therapy are first-line treatment options in current guidelines. We aimed to investigate the combination of home stretching exercises and spinal manipulative therapy in a multicentre randomized controlled clinical trial, carried out in multidiscipline ary primary care clinics.

Methods

The treatment modalities utilized were spinal manipulative therapy and home stretching exercises compared to home stretching exercises alone. Both groups received 4 treatments for 2 weeks. The primary outcome was pain, where the subjective pain experience was investigated by assessing pain intensity (NRS − 11) and the quality of pain (McGill Pain Questionnaire). Neck disability and health status were secondary outcomes, measured using the Neck Disability Indexthe EQ-5D, respectively. One hundred thirty-one adult subjects were randomized to one of the two treatment groups. All subjects had experienced persistent or recurrent neck pain the previous 6 months and were blinded to the other group intervention. The clinicians provided treatment for subjects in both group and could not be blinded. The researchers collecting data were blinded to treatment allocation, as was the statistician performing data analyses. An intention-to-treat analysis was used.

Results

Sixty-six subjects were randomized to the intervention group, and sixty-five to the control group. For NRS − 11, a B-coefficient of − 0,01 was seen, indication a 0,01 improvement for the intervention group in relation to the control group at each time point with a p-value of 0,305. There were no statistically significant differences between groups for any of the outcome measures.

Conclusion

Based on the current findings, there is no additional treatment effect from adding spinal manipulative therapy to neck stretching exercises over 2 weeks for patients with persistent or recurrent neck pain.

Trial registration

The trial was registered 03/07/2018 at ClinicalTrials.gov, registration number: NCT03576846.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04772-x.

Outcomes of scapulothoracic mobilisation in patients with neck pain and scapular dyskinesis: A randomised clinical trial

Objectives

The perceived outcomes of scapulothoracic mobilisation with movement (MWM) in patients with neck pain and scapular dyskinesis remain unclear. This study aimed to examine the effects of adding scapulothoracic MWM to the corrective exercise and taping regimen in patients with neck pain and scapular dyskinesis.

Methods

Forty participants with neck pain and scapular dyskinesis were randomly assigned to one of two 3-week regimens: experimental (scapulothoracic MWM + corrective exercises + tape) or comparison (corrective exercises + tape). The visual analogue scale, pressure pain threshold (PPT), cervical and scapular range of motion (ROM), and neck disability index (NDI) were measured at the start and after the third and sixth sessions.

Results

Pain decreased after the sixth session in both experimental (mean difference: 3.1; 95% confidence interval [CI]: 2.1–4.1) and comparison (mean difference: 1.8; 95% CI: 0.81–2.8) groups. Although there was no change in PPT and scapular ROM, scapular upward rotation decreased significantly only in the comparison group in the sixth session (p = 0.014). The ROM for neck extension, right rotation, and right and left side bending improved significantly (p ≤ 0.031) in both groups. The NDI improved in both the experimental (mean difference: 7.2–10.6; 95% CI: 2.5–15.7) and comparison (mean difference: 5.9–10.3; 95% CI: 1.2–15.4) groups. There were no significant differences in outcomes between the groups.

Conclusions

In this study, the addition of scapulothoracic MWM to the corrective exercise and taping regimen over a 3-week period did not increase pain or improve function in patients with neck pain and scapular dyskinesis.

Persistent sleep disturbance after spine surgery is associated with failure to achieve meaningful improvements in pain and health-related quality of life

BACKGROUND CONTEXT

Little is known about the effects of sleep disturbance (SD) on clinical outcomes after spine surgery.

PURPOSE

To determine the (1) prevalence of SD among patients presenting for spine surgery at an academic medical center; (2) correlations between SD and health-related quality of life (HRQoL) scores; and (3) associations between postoperative SD resolution and short-term HRQoL.

STUDY DESIGN

Retrospective review of prospectively collected data.

PATIENT SAMPLE

We included 508 adults undergoing spine surgery at 1 academic center between December 2014 and January 2018.

OUTCOME MEASURES

Participants completed the Oswestry Disability Index (ODI) or Neck Disability Index (NDI) and Patient Reported Outcome Measurement System (PROMIS-29) questionnaire preoperatively, during the immediate postoperative period (6-12 weeks), and at 6, 12, and 24 months after surgery.

METHODS

Using preoperative PROMIS SD scores, we grouped participants as having no sleep disturbance (score <55), mild disturbance (score, 55-60), moderate disturbance (score 60-70), or severe disturbance (score, 70). For the final analysis, we collapsed these categories into no/mild and moderate/severe. Pearson correlation tests were used to assess correlations between SD and HRQoL measures. Regression analysis (adjusting for age, sex, comorbidities, current opioid use, and occurrence of complications) was used to estimate the effect of postoperative resolved or continuing SD on HRQoL scores and the likelihood of achieving clinically meaningful improvements in HRQoL. Alpha = 0.05.

RESULTS

Preoperative SD was reported by 127 participants (25%). SD was significantly correlated with worse ODI and/or NDI values and worse scores in all PROMIS health domains (all, p<.001). At the immediate postoperative assessment, SD had resolved in 80 of 127 participants (63%). Compared with participants who reported no preoperative SD, those with ongoing SD were significantly less likely to achieve clinically meaningful improvements in Pain Interference (odds ratio [OR], 0.49; 95% confidence interval [CI], 0.28, 0.84), Physical Function (OR, 0.32; 95% CI, 0.13, 0.82), and Satisfaction with Participation in Social Roles (OR, 0.57; 95% CI, 0.37, 0.80).

CONCLUSION

One-quarter of spine surgery patients reported preoperative SD of at least moderate severity. Poor preoperative sleep quality and ongoing postoperative sleep disturbance were significantly associated with worse scores on several HRQoL measures. These results highlight the importance of addressing patients' sleep disturbance both before and after surgery.

Transcultural adaptation of the neck disability index to mexican spanish and assessment of its psychometric properties

PURPOSE

To transculturally adapt the Neck Disability Index to Mexican Spanish (NDI-Mx) and to evaluate its psychometric properties.

METHODS

Translation and transcultural adaptation of the NDI were conducted according to published guidelines. The test-retest reliability of the NDI-Mx was assessed with intraclass correlation coefficient (ICC_3,1), the student t-test, standard error of measurement, minimal detectable change and Bland-Altman plot. Cronbach's α coefficient was used to evaluate internal consistency. Floor and ceiling effects were also evaluated. Convergent validity was assessed by comparison of the NDI-Mx with the Northwick Park Neck Pain Questionnaire (NPQ) through the Spearman correlation coefficient. Finally, a confirmatory factor analysis (CFA) was conducted.

RESULTS

The sample was composed of 113 subjects (38 men and 75 women) with a mean age of 30 (SD, 12.19) years. All items of the NDI-Mx showed good test-retest reliability (ICC_3,1 = 0.86) and good internal consistency (Cronbach's α = 0.85). Floor and ceiling effects were not observed. There was good convergent validity with a high correlation between NDI-Mx and NPQ (ρ = 0.83). The CFA revealed that a one-factor solution fitted adequately the data (χ²(32) = 41.18, p = .13).

CONCLUSION

The NDI-Mx seems to be a valid and reliable tool that can be used in clinical practice and research on Mexican populations with neck pain.

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

BACKGROUND

Neck 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 METHODS

The 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.

RESULTS

The 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%.

CONCLUSION

NDI (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.

Defining threshold values on the neck disability index corresponding to a patient acceptable symptom state in patients undergoing elective surgery for degenerative disorders of the cervical spine

BACKGROUND CONTEXT

The patient acceptable symptom state (PASS) has emerged as a novel tool for interpreting patient-reported outcomes. While the minimal clinically important difference values for various spine outcome instruments have been defined, little is known about the PASS thresholds for these measures.

PURPOSE

To define threshold values on the neck disability index (NDI) corresponding to a PASS in patients undergoing surgery for degenerative disorders of the cervical spine.

STUDY DESIGN

Retrospective review of prospectively collected registry data.

PATIENT SAMPLE

The sample includes 613 patients who underwent anterior cervical discectomy and fusion for degenerative spine conditions between 2005 and 2014.

OUTCOME MEASURES

The main outcome measure was the NDI. The PASS anchor question was adapted from the NASS questionnaire, "How would you rate the overall results of your treatment?" and the validation question was adapted from the AAOS cervical spine questionnaire, "Would you have the same treatment again if you had the same condition?"

METHODS

Patients were assessed preoperatively, 6 months and 2 years postoperatively using the NDI. Responses to the anchor question were dichotomized and used as the external criterion in receiver operating characteristics analysis to define thresholds on the NDI that corresponded to a PASS at 2 years postoperatively. Sensitivity analyses were carried out for various subgroups (age, gender, BMI, comorbidity status), baseline NDI (tertiles), time of follow-up (6 months and 2 years) and an alternate definition of PASS.

RESULTS

Of the 613 patients, 503 (82%) completed 2-year follow-up, of which, 81% reported their current state as acceptable. The areas under the curve (AUC) for the receiver operating characteristics were 0.75 to 0.89 for all analyses, indicating a good ability of the NDI to discriminate between attaining a satisfactory state or not. The PASS threshold was ≤15 points at 6 months (AUC 0.81, sensitivity 73%, specificity 79%) and ≤17 points at 2 years (AUC 0.80, sensitivity 86%, specificity 65%). Sensitivity analyses revealed that the 17-point threshold on the NDI was robust. PASS responders were approximately 12 times more likely to be satisfied (adjusted odds ratio 12.11, 95% confidence intervals 6.96-21.07) and 6 times more willing to undergo surgery again (adjusted odds ratio 6.12, 95% confidence intervals 3.47-10.80) compared to nonresponders.

CONCLUSIONS

Patients with a NDI of ≤17 consider their postoperative symptom state to be acceptable. This PASS threshold can be used alongside the minimal clinically important difference when defining treatment success in spine outcomes studies. At the individual level, this threshold provides clinically relevant benchmarks for surgeons when assessing a patient's postoperative recovery.

Cross-cultural adaptation and psychometric evaluation of the Malay version of the Neck Disability Index

Purpose: Translating the Neck Disability Index (NDI) into the Malay language (NDI-M); evaluation of psychometric properties in patients with neck pain.Methods: The NDI-M was translated according to established guidelines. In the first visit, 120 participants completed the NDI-M, visual analogue scale (VAS) for pain and demographic details. 98 participants returned to complete similar questionnaires and the Global Rating of Change (GRoC) scale. The NDI-M was evaluated for internal consistency, test-retest reliability, content validity, construct validity and responsiveness.Results: The NDI-M demonstrated excellent internal consistency (Cronbach's α = 0.84) and good test-retest reliability (ICC_2,1 = 0.79). Content validity was confirmed with no floor or ceiling effects. Construct validity was established revealing three-factor subscales explaining 68% of the total variance. The NDI-M showed a moderate correlation with VAS (R_p = 0.49, p < 0.001). Regarding responsiveness, a moderate correlation between NDI-M change scores and VAS change scores was found (R_p = 0.40, p < 0.001). However, there was no significant correlation between NDI-M with GRoC (R_s = 0.11, p = 0.27).Conclusions: The NDI-M is a reliable and valid tool to measure functional outcomes in patients with neck pain. It is responsive in detecting changes in pain intensity during a patient's rehabilitation journey.Implications for rehabilitationThe NDI was translated into the Malay language and culturally adapted for Malay-speaking patients with neck pain.The NDI-M demonstrated an excellent level of internal consistency and good test-retest reliability. It demonstrated content and construct validity, with three-factor subscales, and moderate responsiveness for pain intensity.The NDI-M is a reliable, valid and responsive instrument to measure functional limitations in patients with neck pain for rehabilitation.

Effect of external cervical orthoses on clinical and radiological outcome of patients undergoing anterior cervical discectomy and fusion

BACKGROUND

The current use of external cervical orthoses (ECO) after cervical discectomy is still based on a common practice than a solid scientific literature. The aim of this study is to evaluate the impact of ECO on radiological and functional outcomes in patients undergoing anterior cervical discectomy and fusion (ACDF).

METHODS

We compared two cohorts of consecutive patients who underwent ACDF with and without ECO after surgery. Thirty-six patients operated from January 2015 to June 2016 received an ECO whereas 36 patients, operated from July 2016 to December 2017, did not. Each patient underwent radiological and functional evaluation using plain x-ray at 1, 6, and 12 months after surgery and Neck Disability Index (NDI) at 2 weeks and 3, 6, and 12 months after surgery, respectively.

RESULTS

In the ECO group, 5 patients (13.9%) presented an incomplete fusion and 31 patients (86.1%) presented a complete fusion (CI 0.705-0.953). In the non-ECO group, 8 patients (22.2%) presented an incomplete fusion and 28 patients (77.8% [CI 0.608-0.899]) had a complete fusion, with no statistically significant differences between two groups. No statistically significant differences were also observed regarding the NDI neither at 2 weeks nor at 3-, 6-, and 12-month follow-up. At multivariate analysis, patients who underwent two-level ACDF showed a five-fold increased risk of worse NDI at 3-, 6-, 12-month (p = 0.003, CI 1.770-14.584) follow-up.

CONCLUSIONS

We advise against the routine use of ECO after single- or two-level ACDF as we did not find out any significant statistical differences between the two groups.

The NECK trial: Effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; a double-blinded randomized controlled trial

BACKGROUND

Motion preserving anterior cervical disc arthroplasty (ACDA) in patients with cervical radiculopathy was introduced to prevent symptomatic adjacent disc degeneration as compared with anterior cervical discectomy and fusion (ACDF). Prior reports suggest that ACDF is not more effective than anterior cervical discectomy (ACD) alone for the treatment of cervical radiculopathy.

PURPOSE

To evaluate whether patients with cervical radiculopathy due to a herniated disc benefit more from undergoing ACDA, ACDF, or ACD in terms of clinical outcome measured by the neck disability index (NDI).

STUDY DESIGN

Double-blinded randomized controlled trial.

METHODS

One hundred-nine patients with one level herniated disc were randomized to one of the following treatments: ACDA, ACDF with intervertebral cage, ACD without fusion. Clinical and radiological outcome was measured by NDI, Visual Analogue Scale (VAS) neck pain, VAS arm pain, SF36, EQ-5D, patients' self-reported perceived recovery, radiographic cervical curvature, and adjacent segment degeneration parameters at baseline and until two years after surgery. BBraun Medical paid €298.837 to cover the costs for research nurses.

RESULTS

The NDI declined from 41 to 47 points at baseline to 19 ± 15 in the ACD group, 19 ± 18 in the ACDF group, and 20 ± 22 in the ACDA group after surgery (p=.929). VAS arm and neck pain declined to half its baseline value and decreased below the critical value of 40 mm. Quality of life, measured by the EQ-5D, increased in all three groups. Adjacent segment degeneration parameters were comparable in all three groups as well. No statistical differences were demonstrated between the treatment groups.

CONCLUSIONS

The hypothesis that ACDA would lead to superior clinical outcome in comparison to ACDF or ACD could not be confirmed during a 2-year follow-up time period. Single level ACD without implanting an intervertebral device may be a reasonable alternative to ACDF or ACDA.

Correlation of Clinical and Radiological Outcome After Anterior Cervical Discectomy and Fusion With a Polyetheretherketone Cage

Background

Anterior cervical discectomy and fusion (ACDF) with a polyetheretherketone (PEEK) cage is considered as the gold standard for patients with cervical disc disease. However, there are limited in vivo data on the impact of ACDF on the cervical kinematics and its association with patient-reported clinical outcomes. The purpose of this study was to investigate the impact of altered cervical sagittal alignment (cervical lordosis) and sagittal range of motion (ROM) on patients’ self-reported pain and functional disability, after ACDF with a PEEK cage.

Methods

We prospectively studied 74 patients, who underwent single-, or consecutive two-level ACDF with a PEEK interbody cage. The clinical outcomes were assessed by using the pain numeric rating scale (NRS) and the neck disability index (NDI). Radiological outcomes included cervical lordosis and C2-C7 sagittal ROM. The outcome measures were collected preoperatively, at the day of patients’ hospital discharge, and also at 6 and 12 months postoperatively.

Results

There was a statistically significant reduction of the NRS and NDI scores postoperatively at each time point (P < 0.005). Cervical lordosis and also ROM significantly reduced until the last follow-up (P < 0.005). There was significant positive correlation between NRS and NDI preoperatively, as well as at 6 and 12 months postoperatively (P < 0.005). In regard to the ROM and the NDI scores, there was no correlation preoperatively (P = 0.199) or postoperatively (6 months, P = 0.322; 12 months, P = 0.476). Additionally, there was no preoperative (P = 0.134) or postoperative (6 months, P = 0.772; 12 months, P = 0.335) correlation between the NDI scores and cervical lordosis.

Conclusions

In our study, reduction of cervical lordosis and sagittal ROM did not appear to significantly influence on patients’ self-reported disability. Such findings further highlight the greater role of pain level over the mechanical limitations of ACDF with a PEEK cage on patients’ own perceived recovery.

Correlations among visual analogue scale, neck disability index, shoulder joint range of motion, and muscle strength in young women with forward head posture

This study investigated the correlation between the neck disability index (NDI) and visual analogue scale (VAS), which are indicators of neck pain, shoulder joint range of motion (ROM), and muscle strength in women with a slight forward head posture. This study was carried out on 42 female college students attending Uiduk University in Gyeongju, Korea. The neck pain and disability index for each subject was measured using VAS and NDI, respectively. Two physiotherapists measured the shoulder joint ROM and muscle strengths of the subjects using a goniometer and a dynamometer, respectively. External rotation, internal rotation, and abduction of the shoulder joint were measured for each subject. A significant negative correlation between neck pain and shoulder joint ROM in external rotation and the muscle strength of the shoulder joint in abduction was found in the subjects. In addition, a significant positive correlation was observed between ROM in external rotation and muscle strength in abduction. This study showed a significant negative correlation between neck pain and ROM in external rotation as well as between neck pain and the muscle strength in abduction.

[Effectiveness of an individualised physiotherapy program versus group therapy on neck pain and disability in patients with acute and subacute mechanical neck pain]

OBJECTIVE

To compare the efficacy in reducing neck pain and disability in an individualised physiotherapy treatment with group treatment in acute and subacute mechanical neck pain.

DESIGN

Randomised clinical trial.

LOCATION

Health Area of University Hospital Virgen del Rocío, Seville, Spain.

PARTICIPANTS

A total of 90 patients diagnosed with mechanical neck pain of up to one month onset, distributed randomly into two groups: (i)individualised treatment; (ii)group treatment.

INTERVENTION

The treatment consisted of 15 sessions of about 60minutes for both groups. Individual treatment consisted of 15minutes of infrared heat therapy, 17minutes of massage, and analytical passive stretching of the trapezius muscles and angle of the scapula. The group treatment consisted of a program of active mobilisation, isometric contractions, self-stretching, and postural recommendations.

MAIN MEASURES

Pain was measured at the beginning and end of treatment pain using a Visual Analogue Scale (VAS) and an algometer applied on the trapezius muscles and angle of the scapula, and neck disability using the Neck Disability Index.

RESULTS

Both treatments were statistically significant (P<.001) in improving all variables. Statistically significant differences (P<.001) were found for all of them in favour of individualised treatment compared to group treatment.

CONCLUSIONS

Patients with acute or subacute mechanical neck pain experienced an improvement in pain and neck disability after receiving either of the physiotherapy treatments used in our study, with the individual treatment being more effective than collective.

Correlation between rounded shoulder posture, neck disability indices, and degree of forward head posture

[Purpose] The present study aimed to examine the correlation between rounded shoulder posture, neck disability indices and the degree of forward head posture. [Subjects and Methods] Subjects aged 19-24 years were selected for this study, and the craniovertebral angle was used to measure the degree of forward head posture in the standing and seated positions. Vernier calipers were used to measure rounded shoulder posture in the supine position, and neck pain and functional disability were assessed using neck disability indices. [Results] Angle and neck disability indices in both standing and sitting posture positions exhibited a significant inverse relationship. However, no significant correlation was detected between the craniovertebral angle and rounded shoulder posture for the standing and sitting posture positions. [Conclusion] In conclusion, it was demonstrated in the present study that, depending on the degree of forward head posture, changes were detected in the neck disability indices. However, even an increase in the forward head tilt angle did not lead to rounded shoulder posture. Therefore, maintaining proper posture may prevent postural pain syndrome, functional disability, and postural deformity.

The effect of feedback respiratory exercise on muscle activity, craniovertebral angle, and neck disability index of the neck flexors of patients with forward head posture

[Purpose] This study aimed to simultaneously investigate the activities of the sternocleidomastoid muscle and scalenus anterior muscle, which are agonists of neck and breathing accessory muscles, by implementing breathing exercises. [Subjects and Methods] Thirteen subjects were selected for the experimental group, which performed feedback respiratory exercises with McKenzie exercises, and 12 subjects were selected for the control group, which performed McKenzie exercises alone. The intervention program was performed for 30 minutes a session, once a day, four times a week, and for 2 weeks before conducting the experiment. Before intervention, muscle activity was measured using surface electromyogram, and the neck disability index was evaluated. [Results] There were meaningful differences in activities of the sternocleidomastoid muscle and the scalenus anterior muscle, craniovertebral angle, and neck disability index within both the experimental group and control group after intervention. There also were meaningful differences in sternocleidomastoid muscle and neck disability index changes between groups. [Conclusion] Neck flexors as accessory respiratory muscle can affect inefficient respiratory imbalance of forward head posture patients. Multimodal intervention method should be studied continually and not be exposed to upper chest breathing patterns by preventing such phenomenon.

Therapeutic patient education and exercise therapy in patients with cervicogenic dizziness: a prospective case series clinical study

The purpose of this study was to evaluate the effectiveness of a treatment for patients with cervicogenic dizziness that consisted of therapeutic education and exercises. The Dizziness Handicap Inventory and Neck Disability Index were used. Secondary outcomes included range of motion, postural control, and psychological variables. Seven patients (two males and five females) aged 38.43±14.10 with cervicogenic dizziness were included. All the participants received eight treatment sessions. The treatment was performed twice a week during a four weeks period. Outcome measures included a questionnaire (demographic data, body chart, and questions about pain) and self-reported disability, pain, and psychological variables. Subjects were examined for cervical range of motion and postural control. All of these variables were assessed pre- and postintervention. Participants received eight sessions of therapeutic education patient and therapeutic exercise. The majority of participants showed an improvement in catastrophism (mean change, 11.57±7.13; 95% confidence interval [CI], 4.96–18.17; d=1.60), neck disability (mean change, 5.14±2.27.28; 95% CI, 3.04–7.24; d=1.32), and dizziness disability (mean change, 9.71±6.96; 95% CI, 3.26–16.15; d=1.01). Patients also showed improved range of motion in the right and left side. Therapeutic patient education in combination with therapeutic exercise was an effective treatment. Future research should investigate the efficacy of therapeutic patient education and exercise with larger sample sizes of patients with cervicogenic dizziness.

Correlation among scapular asymmetry, neck pain, and neck disability index (NDI) in young women with slight neck pain

[Purpose] This study aimed to investigate the correlations among scapular asymmetry, neck pain, and neck disability index in women in their 20s with slight neck pain. [Subjects and Methods] A total of 60 female students at U university in Gyeongsangbuk-do, South Korea, participated in this study. The lateral scapular slide test, which measures the distance between the thorax and scapula, was used to analyze the scapular asymmetry. The lateral scapular slide test was performed in three positions. The visual analogue scale and neck disability index were used to measure neck pain. [Results] In the lateral scapular slide test in position 3 (shoulder abduction at 90 degrees), the scapular left-right asymmetry and VAS showed a moderate positive linear relationship, with r=0.344. The VAS and NDI showed a moderate positive linear relationship, with r = 0.632. [Conclusion] Scapular asymmetry indicates imbalance of surrounding muscles of the scapula and is related to neck pain based on the results of measuring the distance from the thorax to the scapula.

Comparison of cervical kinematics between patients with cervical artificial disc replacement and anterior cervical discectomy and fusion for cervical disc herniation

BACKGROUND CONTEXT

Although anterior cervical discectomy and fusion (ACDF) is an effective treatment option for patients with cervical disc herniation, it limits cervical range of motion, which sometimes causes discomfort and leads to biomechanical stress at neighboring segments. In contrast, cervical artificial disc replacement (ADR) is supposed to preserve normal cervical range of motion than ACDF. A biomechanical measurement is necessary to identify the advantages and clinical implications of ADR. However, literature is scarce about this topic and in those available studies, authors used the static radiological method, which cannot identify three-dimensional motion and coupled movement during motion of one axis.

PURPOSE

The purpose of this study was to compare the clinical parameters and cervical motion by three-dimensional motion analysis between ACDF and ADR and to investigate the ability of ADR to maintain cervical kinematics.

STUDY DESIGN

This was a prospective case control study.

PATIENT SAMPLE

Patients who underwent ADR or ACDF for the treatment of single-level cervical disc herniation.

OUTCOME MEASURES

Visual analog scale (VAS), Korean version of Neck Disability Index (NDI, %), and three-dimensional motion analysis were used.

METHODS

The patients were evaluated by VAS and the Korean version of the NDI (%) to assess pain degree and functional status. Cervical motions were assessed by three-dimensional motion analysis in terms of sagittal, coronal, and horizontal planes. Markers of 2.5 cm in diameter were attached at frontal polar (Fpz), center (Cz), and occipital (Oz) of 10-20 system of electroencephalography, C7 spinous process, and both acromions. These evaluations were performed preoperatively and 1 month and 6 months after surgery.

RESULTS

The ACDF and ADR groups revealed no significant difference in VAS, NDI (%), and cervical range of motion preoperatively. After surgery, both groups showed no significant difference in VAS and NDI (%). In motion analysis, significantly more range of motion was retained in flexion and extension in the ADR group than the ACDF group at 1 month and 6 months. There was no significant difference in lateral tilt and rotation angle. In terms of coupled motion, ADR group exhibited significantly more preserved sagittal plane motion during right and left rotation and also showed significantly more preserved right lateral bending angle during right rotation than ACDF group at 1 month and 6 months. There was no significant difference in other coupled motions.

CONCLUSION

Three-dimensional motion analysis could provide useful information in an objective and quantitative way about cervical motion after surgery. In addition, it allowed us to measure not only main motion but also coupled motion in three planes. ADR demonstrated better retained cervical motion mainly in sagittal plane (flexion and extension) and better preserved coupled sagittal and coronal motion during transverse plane motion than ACDF. ADR had the advantage in that it had the ability to preserve more cervical motions after surgery than ACDF.