The Spine Journal 14 (2014) 759–767

Clinical Study

Early postoperative fear of movement predicts pain, disability, and physical health six months after spinal surgery for degenerative conditions Kristin R. Archer, PhD, DPTa,*, Caryn L. Seebach, PsyDb, Shannon L. Mathis, PhDa, Lee H. Riley, III, MDc, Stephen T. Wegener, PhDd a

Department of Orthopaedic Surgery & Rehabilitation, Vanderbilt University, School of Medicine, Medical Center East – South Tower, Suite 4200, Nashville, TN 37232, USA b Department of Psychology, Washington DC VA Medical Center, 50 Irving St, NW, Washington, DC 20422, USA c Department of Orthopaedic Surgery, Johns Hopkins Medicine, 601 N. Carolina St, Baltimore, MD 21287, USA d Department of Physical Medicine and Rehabilitation, Johns Hopkins Medicine, 600 N. Wolfe St, Baltimore, MD 21287, USA Received 25 April 2012; revised 25 April 2013; accepted 24 June 2013

Abstract

BACKGROUND CONTEXT: The fear-avoidance model offers a promising framework for understanding the development of chronic postoperative pain and disability. However, limited research has examined this model in patients undergoing spinal surgery. PURPOSE: To determine whether preoperative and early postoperative fear of movement predicts pain, disability, and physical health at 6 months following spinal surgery for degenerative conditions, after controlling for depressive symptoms and other potential confounding variables. STUDY DESIGN/SETTING: A prospective cohort study conducted at an academic outpatient clinic. PATIENT SAMPLE: One hundred forty-one patients undergoing surgery for lumbar or cervical degenerative conditions. OUTCOME MEASURES: Self-reported pain and disability were measured with the Brief Pain Inventory and the Oswestry Disability Index/Neck Disability Index, respectively. The physical composite scale of the 12-Item Short-Form Health Survey (SF-12) measured physical health. METHODS: Data collection occurred preoperatively and at 6 weeks and 6 months following surgery. Fear of movement was measured with the Tampa Scale for Kinesiophobia and depression with the Prime-MD PHQ-9. RESULTS: One hundred and twenty patients (85% follow-up) completed the 6-month postoperative assessment. Multivariable mixed-method linear regression analyses found that early postoperative fear of movement (6 weeks) predicted pain intensity, pain interference, disability, and physical health at 6-month follow-up (p!.05). Preoperative and early postoperative depression predicted pain interference, disability, and physical health. CONCLUSION: Results provide support for the fear-avoidance model in a postsurgical spine population. Early postoperative screening for fear of movement and depressive symptoms that do not acutely improve following surgical intervention appears warranted. Cognitive and behavioral strategies may be beneficial for postsurgical patients with high fear of movement and/or depressive symptoms. Ó 2014 Elsevier Inc. All rights reserved.

Keywords:

Fear of movement; Depression; Spine surgery; Postoperative pain; Rehabilitation

FDA device/drug status: Not applicable. Author disclosures: KRA: Grant: Blaustein Fund (C, Paid directly to institution/employer); Grants: APTA (C, Paid directly to institution/employer), Foundation of Physical Therapy (D, Paid directly to institution/employer). CLS: Nothing to disclose. SLM: Nothing to disclose. LHR: Grant: Blaustein Fund (C, Paid directly to institution/employer). STW: Grant: Blaustein Fund (C, Paid directly to institution/employer). The disclosure key can be found on the Table of Contents and at www. TheSpineJournalOnline.com. 1529-9430/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.spinee.2013.06.087

This research was supported with funds from the Blaustein Pain Research Fund, the Blaustein Pain Treatment Center, Johns Hopkins Medicine. * Corresponding author. Department of Orthopaedic Surgery and Rehabilitation, Vanderbilt University, School of Medicine, Medical Center East – South Tower, Suite 4200, Nashville, TN 37232, USA. Tel.: (615) 322-2732; fax: (615) 936-1566. E-mail address: [email protected] (K.R. Archer)

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Context Psychosocial factors can impact outcomes following surgery. The authors assess fear of movement. Contribution In this prospective cohort study, the authors found that early postoperative fear of movement and depressive symptoms are associated with inferior outcomes at six months postoperative. Implications Early identification and intervention may make a difference—assuming that the association is one of direct or indirect causation. —The Editors

Introduction The fear-avoidance model of Vlaeyen et al. [1], based on the work of Lethem et al. [2], Philips [3], and Waddell et al. [4], provides clinicians with a cognitive-behavioral framework for understanding chronic pain syndromes. Robust evidence supports the fear-avoidance model in patients with various musculoskeletal conditions [5], such as back and neck pain [6,7], osteoarthritis [8], and fibromyalgia [9]. The model suggests that after an injury there are two pathways based on the way acute pain is interpreted. Pain that is perceived as nonthreatening will lead to a return to normal activity, but pain that is perceived as threatening will promote anxiety and give rise to pain-related fear that persists beyond the expected healing time. This fear leads to avoidance behaviors and a ‘‘disuse’’ syndrome that is associated with deconditioning and depression, which subsequently perpetuates the pain process. The fear-avoidance model offers a promising framework for the development of chronic postoperative pain and disability. Two studies have demonstrated a predictive relation between preoperative pain catastrophizing (ie, tendency to magnify pain sensations) and increased pain after knee arthroplasty surgery [10,11]. In patients following lumbar disc surgery, Johansson et al. [12] and den Boer and colleagues [13,14] found that preoperative fear of movement was the best predictor of low quality of life (QOL) at 12-month follow-up and increased pain and disability at 6-month follow-up, respectively. Mannion et al. [15] reported that preoperative fear-avoidance beliefs about work, but not activity, was a significant predictor of disability 6 months after surgery in a variety of spinal disorders. Limited research has examined the fear-avoidance model in patients undergoing spinal surgery for degenerative conditions. Abbott et al. [16] reported significant correlations between preoperative fear of movement and preoperative

pain, disability, and QOL outcomes in patients after lumbar spine fusion. In our own work, a significant association was found between postoperative fear of movement and pain, disability, and physical health at 6 weeks and 3 months after laminectomy with or without arthrodesis [17]. Surgery rates for degenerative conditions have been rising steadily since the 1990s [18,19], and fusion procedures account for almost half of the $1 billion spent annually by Medicare on spinal surgery [20]. Despite rapid increases in surgery rates, individuals after surgery for spinal degeneration continue to have poorer physical and mental functioning compared with the general United States population [21,22]. More specifically, up to 40% report residual chronic pain and functional disability [23–26]. Thus, the primary purpose of this study was to determine whether preoperative and early postoperative fear of movement predicts pain, disability, and physical health at 6 months following spinal surgery for degenerative conditions, after controlling for depressive symptoms and other potential confounding variables. We hypothesized that both preoperative and early postoperative fear of movement would be a significant predictor of 6-month outcomes. Methods Participants A total of 244 patients were referred to this study over a 21-month period by participating spine surgeons. Two hundred were eligible and 141 patients undergoing surgery for a lumbar (n592) or cervical (n549) degenerative condition were enrolled in the study after providing informed consent. Degenerative conditions included spinal stenosis, spondylosis with or without myelopathy, and spondylolisthesis. Patients who had surgery for spinal deformity as the primary indication, microsurgical techniques as the primary procedure, such as an isolated laminotomy or microdiscectomy, or surgery secondary to pseudarthrosis, trauma, infection, or tumor were excluded from the study. Specific inclusion criteria were (1) age older than 18 years, (2) English speaking, (3) spine and/or extremity pain for longer than 6 months, (4) radiographic evidence of compression of nerve roots by degenerative changes, (5) no medical history of schizophrenia or other psychotic disorder, and (6) no presence of comorbidities or injuries requiring rehospitalization after spinal surgery. Mean age of the participants was 59.1 years (standard deviation (SD)513.3, range 21–88), 58% were female, 49% had a college or graduate degree, and 81% were non-Hispanic white. Procedures Eligible and consented patients were approached by study personnel before surgery and asked to complete a preoperative assessment consisting of demographic questions and self-report instruments measuring fear of movement, depression, pain, disability, and physical health. Follow-up

K.R. Archer et al. / The Spine Journal 14 (2014) 759–767

assessments, using the same battery of self-report instruments, were conducted at 6 weeks and 6 months after surgery during standard postoperative clinic visits. Assessments were mailed to those patients not returning to the clinic. If a patient did not respond within 1 week of mailing the battery of instruments, he or she was contacted by telephone and asked to complete and return the questionnaire within 5 days. The study was approved by the institutional review board at the participating site. Measures Demographic and health variables Participants were asked questions with regard to age in years; sex; race; highest grade or year in school they had completed; number of days of the week they exercise; and marital, work, and smoking status. Comorbidities were assessed using the Charlson Comorbidity Index (CCI) [27], a well-validated means of risk adjustment for in-hospital complications and mortality. Surgery variables The type of surgery, area of surgery (lumbar or cervical), and number of prior spinal surgeries were abstracted from the medical record. Fear of movement The 17-item Tampa Scale for Kinesiophobia (TSK) was used to measure fear of movement [28]. A total score can range from 17 to 68, with a score greater than 39 indicating high fear of movement [1,17,29]. Participants are asked to rate each item, 4 being negatively worded and reversescored (items 4, 8, 12, and 16), on a 4-point Likert scale with scoring alternatives ranging from ‘‘strongly disagree’’ to ‘‘strongly agree.’’ The TSK has been validated as a reliable index of fear of movement with good internal consistency (Cronbach’s alpha O0.70) and test-retest reliability (Pearson’s r O0.70) in patients with chronic pain [9,30]. The TSK was found to have an internal consistency of 0.73 in the current study. Depression The 9-Item Primary Care Evaluation of Mental Disorders Patient Health Questionnaire (Prime-MD PHQ-9 [31]) assessed depressive symptoms. Each of the nine items has four possible answers to quantify how often a patient has had a particular depressive symptom: not at all, several days, more than half the days, and nearly every day. Each item is scored from 0 to 3 with total scores for the Prime-MD PHQ-9 ranging from 0 to 27. A score of 10 or higher is the most commonly recommended cutpoint for ‘‘clinically significant’’ depressive symptom [32]. The Prime-MD PHQ-9 has demonstrated excellent reliability (Cronbach’s alpha O0.85 and Pearson’s r O0.80) and compared with independent diagnoses made by mental health professionals, the instrument has been found to be both

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sensitive (0.75) and specific (0.90) for the diagnosis of major depression in a primary care setting [33]. Pain intensity and interference The Brief Pain Inventory (BPI) [34] measured both pain intensity and pain interference with daily activity. The pain intensity subscale characterizes sensory pain and consists of four items that assess current, worst, least, and average pain, whereas the pain interference subscale consists of seven items that assess general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life. Both subscales use a numerical rating scale with 0 representing ‘‘no pain or does not interfere’’ and 10 representing ‘‘pain as bad as you can imagine or completely interferes.’’ Scores greater than or equal to 5 indicate moderate to severe pain intensity and interference. The BPI has proven both reliable (Cronbach’s alpha O0.80) and valid (highly correlated with wellvalidated generic measures of pain and general health and condition-specific disability) in both surgical patients and patients with chronic low back pain [35,36]. Disability The Oswestry Disability Index (ODI) and Neck Disability Index (NDI) were used to measure low back and neck disability, respectively [37,38]. These 10-item instruments assess the impact of spinal disorders on daily living, with the ODI asking questions about pain intensity, lifting, sitting, standing, walking, sleeping, hygiene, traveling, social life, and sex life and the NDI about pain intensity, personal care, lifting, reading, headache, concentration, work, driving, sleeping, and recreation. Ratings for each item on both instruments range from 0 (high functioning) to 5 (low functioning) and total scores are divided by the total possible score and multiplied by 100 to create a percentage of disability. Scores on the ODI and NDI above 40% classify individuals as having severe disability. These instruments have demonstrated excellent test–retest reliability (Pearson’s r O0.80) and good internal consistency (Cronbach’s alpha O0.70) and validity with moderately high correlations with the 36-item Short Form Health Survey (SF-36), the Visual Analog Scale for pain, and various wellvalidated condition-specific disability measures [37–40]. Physical health The physical composite scale (PCS) of the 12-item Short-Form Health Survey (SF-12) [41] measured generic physical health. Items assess the four physical subdomains of limitations in physical activities, limitations in usual role activities because of physical health, bodily pain, and general health perception. Total scores range from 0 to 100, where 0 indicates the lowest level of health and 100 the highest level of health. The PCS of the SF-12 has demonstrated excellent test–retest reliability (Pearson’s r O0.80) and good internal consistency (Cronbach’s alpha O0.70) and validity, with correlations greater than 0.90 with the

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SF-36 in generalized and various patient populations [41–43].

Table 1 Baseline demographic and clinical characteristics of study population

Statistical analysis Descriptive statistics were used to explore the mean and median scores and SDs of fear of movement, depression, pain intensity, pain interference, disability, physical health, and the continuous baseline variables of age and CCI score. All continuous variables were examined for the assumptions required for parametric analyses. Student’s t tests or Wilcoxon rank sum tests and chisquare tests assessed preoperative and postoperative differences in scales as well as patient demographic and clinical characteristics by area of surgical procedure (lumbar vs. cervical) to support combining patients into a single group for subsequent analyses. Significant differences between preoperative and 6-week and 6-month follow-up data were examined with dependent Student’s t tests or Wilcoxon signed-rank tests. Separate multivariable mixed-model linear regression analyses were performed to examine the relation between both preoperative and 6-week postoperative fear of movement and the 6-month outcomes of interest. All models included a random effect to control for the clustering of patients by surgeon. Variables that were considered to be relevant to the outcomes were entered into each model for analysis. These a priori variables for the analyses examining preoperative fear of movement included age; sex; race; education; CCI score; type and area of surgery; prior spinal surgeries; preoperative depression; and level of preoperative pain, disability, or functional status depending on outcome of interest. For the analyses examining 6-week postoperative fear of movement, covariates were similar except 6-week postoperative depressive symptoms and 6-week pain, disability, or functional status were included instead of preoperative levels. All multivariable analyses were performed on patients with 6-month follow-up data (n5120). Missing data were less than 5% for fear of movement, depression, and outcome variables and were handled in a 2-step process. First, missing items from the scales were imputed based on a single mean imputation. Second, multiple imputation was performed for missing scores (all items missing) using additive imputation models that imputed the missing values as a function of the other covariates. More specifically, each regression model was fitted for five simulated complete datasets and the results were combined to produce a final estimate [44]. The stability of the final models was confirmed by comparing results to analyses with only observed data. SAS software (version 9.1.3; SAS Institute, Cary, NC) was used to analyze the data. The level of significance was set at p!.05.

Results Of the 200 eligible patients approached, 141 (71%) agreed to participate in the study. There were no significant

Characteristic Mean age (SD) Sex Male Female Race White Nonwhite Education Less than high school Some college College degree Graduate degree Marital status Married Not married Usual major activity Working Laid off/looking Homemaking/school Retired (not due to illness) Retired (due to illness) Regular exercise None 1x/week 2–3x/week O3x/week Smoking history Never Former Current Surgery Fusion Other type Prior spinal surgery None 1 $2

Total (N5141) N (%)

Lumbar (n592) n (%)

Cervical (n549) n (%)

59.1 (13.3)

63.7 (19.5)

55.4 (12.4)

59 (42) 82 (58)

36 (39) 56 (61)

23 (47) 26 (53)

114 (81) 27 (19)

75 (82) 17 (18)

39 (80) 10 (20)

22 26 20 24

13 11 10 15

35 37 30 39

(25) (26) (21) (28)

104 (74) 37 (26)

(24) (28) (22) (26)

(27) (22) (20) (31)

66 (72) 26 (28)

38 (78) 11 (22)

52 19 14 41 15

(37) (13) (10) (29) (11)

27 15 10 31 9

(29) (16) (11) (34) (10)

25 4 4 10 6

(52) (8) (8) (20) (12)

53 19 45 24

(38) (13) (32) (17)

37 12 30 13

(40) (13) (33) (14)

16 7 15 11

(33) (14) (31) (22)

60 (42) 66 (47) 15 (11)

37 (40) 46 (50) 9 (10)

23 (47) 20 (41) 6 (12)

107 (76) 34 (24)

62 (67) 30 (33)

45 (92) 4 (8)

95 (67) 34 (24) 12 (9)

62 (67) 21 (23) 9 (10)

33 (67) 13 (27) 3 (6)

SD, standard deviation.

differences with regard to age, sex, race, insurance status, surgery type and area, and prior spinal surgery between eligible patients who were enrolled and those who were not enrolled. Of the 141 enrolled participants, 128 (91% follow-up) completed the 6-week and 120 (85% followup) completed the 6-month postoperative assessment. There were no significant differences between patients with and without follow-up data on demographic and surgery characteristics, fear of movement, depression, and outcome variables. Preliminary analyses determined that patients with lumbar and cervical degeneration were not significantly different on measures of preoperative or postoperative fear of movement, depression, pain, disability, and physical health or on baseline demographic characteristics. As a result, all patients were combined into one sample for further analyses. Participant demographic and clinical characteristics by area of surgery are presented in Table 1.

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Table 2 Comparison of preoperative and postoperative scores for fear of movement, depression, pain intensity, pain interference, disability, and physical health Mean6SD (median) Variables Fear of movement (TSK) Depression (PHQ-9) Outcomes Pain intensity (BPI) Pain interference (BPI) Disability (ODI/NDI) Physical health (SF-12)

Preoperative (N5141)

6 Wk (N5128)

43.966.6 (44) 7.766.0 (7) 5.662.3 6.062.4 43.2615.5 28.669.3

6 Mo (N5120)

39.065.5 (38)* 5.665.2 (4)*

(6) (6) (43) (28)

3.062.1 3.362.6 37.6619.0 29.668.6

37.866.9 (38)* 5.064.9 (4)*

(3)* (3)* (36)* (29)*

2.862.5 2.662.6 27.5618.9 37.5611.0

(2.3)* (2)* (24.4)* (34.5)*

BPI, Brief Pain Inventory; NDI, Neck Disability Index; ODI, Oswestry Disability Index; PHQ-9, 9-item Primary Care Evaluation of Mental Disorders Patient Health Questionnaire; SD, standard deviation; SF-12, 12-Item Short-Form Health Survey; TSK, Tampa Scale for Kinesiophoia. * p!.001.

Clinical course of fear of movement, depression, and outcomes There were statistically significant decreases in fear of movement, depression, pain, and disability and increases in physical health from preoperative to both 6-week and 6-month follow-up (p!.001) (Table 2). Depression, pain interference, disability, and physical health were also noted to improve between the 6-week and 6-month time points (p!.05). However, no statistically significant improvement was noted between 6-week and 6-month fear of movement and pain intensity. Seventy-four percent of patients reported high preoperative fear of movement (TSK O39) and 49% and 42% continued to have high fear of movement at 6 weeks and 6 months following spinal surgery, respectively. Preoperative fear of movement and 6-month outcomes Preoperative fear of movement was not a significant predictor of postoperative outcomes at 6 months after spinal surgery (Table 3). However, preoperative depressive symptoms

predicted increased pain interference (b50.09; 95% confidence interval [CI]50.00–0.18) and disability (b50.65; 95% CI50.04–1.3) and decreased physical health (b50.54; 95% CI50.86 to 0.21) at 6 months. Results demonstrate that for every 10-point increase on the PrimeMD PHQ-9 (range 0–27) as measured at the preoperative period; there was a 0.9-point increase on the BPI interference scale (range 0–10), 6.5-point increase on the ODI or NDI (range 0–100), and a 5.4-point decrease on the physical component of the SF-12 (range 0–100) at 6 months. Having a college or graduate degree was predictive of decreased pain (b51.1; 95% CI52.0 to 0.26) and having surgery other than a fusion was predictive of increased disability (b59.5; 95% CI51.9–17.2) and decreased physical health (b56.8; 95% CI511.4 to 2.1) at 6-month follow-up. Six-week postoperative fear of movement and 6-month outcomes Higher levels of fear of movement at 6 weeks after surgery was predictive of increased pain intensity (b50.09;

Table 3 Multivariable mixed-model linear regression analyses for preoperative fear of movement and 6-month pain, disability, and physical health (N5120)

Preoperative fear of movement Preoperative depression Patient characteristics Age, y Female versus male, ref White versus nonwhite, ref College degree versus less than college, ref Comorbidity (CCI) Surgery characteristics Other versus fusion, ref Lumbar versus cervical, ref $1 prior spine surgery versus none, ref

Pain intensity

Pain interference

Disability

Physical health

b (95% CI)

b (95% CI)

b (95% CI)

b (95% CI)

0.04 (0.56 to 0.49) 0.65 (0.04–1.3)*

0.18 (0.48 to 0.13) 0.54 (0.86 to 0.21)y

0.04 (0.03 to 0.11) 0.07 (0.01 to 0.15) 0.02 0.51 0.30 1.1 0.01

(0.06 to 0.03) (1.4 to 0.36) (1.3 to 0.70) (2.0 to 0.26)* (0.09 to 0.07)

0.50 (0.56 to 1.6) 0.13 (0.78 to 1.0) 0.09 (0.97 to 0.79)

0.08 (0.01–0.15) 0.09 (0.00–0.18)* 0.02 0.27 0.04 0.93 0.04

(0.07 (1.21 (1.11 (1.88 (0.05

to to to to to

0.02) 0.66) 1.03) 0.02) 0.13)

0.89 (0.24 to 2.03) 0.39 (0.60 to 1.38) 0.01 (0.97 to 0.95)

0.04 2.1 2.8 5.3 0.16

(0.26 to 0.35) (8.2 to 4.0) (4.3 to 10.1) (11.6 to 1.1) (0.43 to 0.75)

9.5 (1.9–17.2)* 0.10 (6.7 to 6.5) 1.3 (5.1 to 7.7)

0.04 0.69 1.05 2.50 0.29

(0.23 to 0.14) (3.0 to 4.4) (3.3 to 5.4) (1.3 to 6.3) (0.64 to 0.06)

6.8 (11.4 to 2.1)* 1.8 (5.7 to 2.1) 2.8 (6.6 to 1.0)

b, regression coefficient (slope of the linear relationship between the outcome and the predictor variable independent of the other variables in the model); CCI, Charlson Comorbidity Index; CI, confidence interval; ref, reference. Models also included a variable to represent preoperative level of pain, disability, or functional status depending on outcome of interest and random effect to account for clustering of visits by surgeon. * p!.05. y p!.01.

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Table 4 Multivariable mixed-model linear regression analyses for 6-week fear of movement and 6-month pain, disability, and physical health (N5120)

6-week fear of movement 6-week depression Patient characteristics Age, y Female versus male, ref White versus nonwhite, ref College degree versus less than college, ref Comorbidity (CCI) Surgery characteristics Other versus fusion, ref Lumbar versus cervical, ref $1 prior spine surgery versus none, ref

Pain intensity

Pain interference

Disability

b (95% CI)

b (95% CI)

b (95% CI)

0.09 (0.01–0.16)* 0.07 (0.00–0.15) 0.003 0.43 0.47 1.2

(0.05 to 0.04) (1.3 to 0.43) (1.5 to 0.52) (2.1 to 0.31)y

0.03 (0.11 to 0.05) 0.36 (0.65 to 1.38) 0.18 (0.71 to 1.1) 0.17 (1.0 to 0.68)

0.13 (0.05–0.20)y 0.10 (0.01–0.19)* 0.004 0.14 0.26 1.0

(0.05 to 0.04) (1.04 to 0.77) (1.3 to 0.80) (1.9 to 0.07)*

0.02 (0.07 to 0.10) 0.63 (0.45 to 1.71) 0.48 (0.48 to 1.4) 0.18 (1.1 to 0.72)

0.68 (0.22–1.1)y 1.4 (0.84–1.9)y 0.11 0.96 2.2 4.9

(0.17 to 0.38) (6.1 to 4.2) (4.3 to 8.7) (10.6 to 0.74)

0.21 (0.33 to 0.75) 1.8 (7.7 to 4.1) 0.52 (2.2 to 6.4) 0.17 (4.9 to 5.3)

Physical health b (95% CI) 0.51 (0.81 to 0.21)y 0.54 (0.84 to 0.24)z 0.21 0.20 2.2 2.7

(0.31 to 0.06) (3.4 to 3.8) (1.9 to 6.4) (0.94 to 6.3)

0.18 (0.52 to 0.16) 5.9 (10.4 to 1.6)y 2.2 (5.9 to 1.6) 2.4 (5.9 to 1.2)

b, regression coefficient (slope of the linear relationship between the outcome and the predictor variable independent of the other variables in the model); CCI, Charlson Comorbidity Index; CI, confidence interval; ref, reference. Models also included a variable to represent 6 week level of pain, disability, or functional status depending on outcome of interest and random effect to account for clustering of visits by surgeon. * p!.05. y p!.01. z p!.001.

95% CI50.01–0.16), pain interference (b50.13; 95% CI50.05–0.20), and disability (b50.68; 95% CI50.22– 1.1) and decreased physical health (b50.51; 95% CI50.81 to 0.21) at 6-month follow-up (Table 4). In addition, higher levels of depressive symptoms at 6 weeks was predictive of increased pain interference (b50.10; 95% CI50.01–0.19) and disability (b51.4; 95% CI50.84–1.9) and decreased physical health (b50.54; 95% CI50.84 to 0.24) at 6-month follow-up. Results demonstrate that for every 10-point increase on the TSK (range 17–68); there was a 0.9-point and 1.3-point increase on the pain intensity and pain interference scales of the BPI, respectively, a 6.8-point increase on the ODI or NDI, and a 5.1-point decrease on the physical component of the SF-12. For every 10-point increase on the PrimeMD PHQ-9; there was a 1-point increase on the pain interference scale of the BPI, a 14-point increase on the ODI or NDI, and a 5.4-point decrease on the SF-12. Having a college or graduate degree was predictive of decreased pain intensity (b51.2; 95% CI52.1 to 0.31) and pain interference (b51.0; 95% CI51.9 to 0.07) and having surgery other than a fusion was predictive of decreased physical health (b55.9; 95% CI510.4 to 1.6) at 6-month follow-up. Discussion The primary purpose of this study was to determine whether preoperative and early postoperative fear of movement predicted 6-month outcomes following surgery for degenerative conditions. Demonstration of this relation would inform clinical decisions regarding the need for screening and targeted treatment. Results partially supported our

hypothesis for early postoperative, but not preoperative, fear of movement, which was found to be a risk factor for increased pain and disability and decreased physical health at 6 months following surgery. Implications of our data appear to be that screening for fear of movement should occur at an early postoperative clinic visit to identify patients at risk for poor long-term postoperative outcomes. Although our results are consistent with other studies [12–14,16] in supporting the important role of cognitivebehavioral variables in outcomes after spinal surgery, our data do not support work by Johansson et al. [12], den Boer et al. [13,14], and Abbott and colleagues [16], who found a relation between preoperative fear of movement and surgical outcomes. Our nonsignificant finding may be due to differences in participants’ clinical characteristics. Johansson et al. [12] and den Boer et al. [13,14] included patients undergoing first-time lumbar disc surgery, whereas Abbott et al. [16] included first-time fusion surgery. In our study, 33% of patients had at least one prior surgery for spinal degeneration. Furthermore, patients in the current study demonstrated higher preoperative fear of movement, pain, and disability, with greater decline over the postoperative recovery period compared with these previous studies in spine surgery populations [12–14]. Our results do support preoperative screening for depressive symptoms to identify patients at risk for poorer postoperative outcomes, which is consistent with several prospective studies in patients with degenerative spinal stenosis. Sinikallio and colleagues [45,46] have consistently reported a significant association between preoperative depression and pain and disability up to 2 years after surgery. Trief et al. [47] found that preoperative depression predicted decreased return to work and functional abilities at

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1 year follow-up. In addition, studies have demonstrated significant associations between preoperative depression and pain at 6 months [48], disability and physical health at 18 months [49], and symptom severity and disability at 2 years [50,51] following surgery for lumbar degenerative conditions. As expected, postoperative fear of movement at 6-week follow-up predicted postoperative pain, disability, and physical health outcomes 6 months after surgery, even after controlling for 6-week depressive symptoms and pain. This finding is clinically relevant, as most patients have the first postoperative clinic visit approximately 6 weeks after hospital discharge. Patients are usually referred to physical therapy and other health care providers at this visit, which provides clinicians with an optimal time point for screening so as to inform referral and treatment. Furthermore, no significant differences were noted between 6-week and 6-month fear of movement, indicating that fear of movement remains relatively stable during the postoperative period. Our results support the recommendation by Ostelo et al. [52] that future research in spinal surgery should focus on the early identification of subgroups at risk for poor outcomes and on psychosocial factors, such as fear of movement, as part of rehabilitation. In addition to being stable, fear of movement remained high postoperatively, with 49% and 42% of patients having clinically significant scores at 6 weeks and 6 months, respectively. Postoperative scores in our surgical population are also consistent with the chronic pain literature. Although some studies report average TSK scores as high as 44 [53,54], the average range in patients with chronic back and neck pain is 38 to 41 [1,30,55]. This comparison indicates that postsurgical spine patients continue to resemble chronic pain patients and may benefit from cognitive and behavioral strategies that have proven effective for low back and neck pain [56,57]. Specific cognitive-behavioral components that have demonstrated effectiveness through randomized controlled trials include graded activity and exposure in vivo, and goal-setting, relaxation, pacing, and problem-solving strategies [58–60]. Furthermore, targeted physical therapy interventions to reduce psychosocial barriers to rehabilitation have shown promise in low back and neck pain populations. Sullivan et al. [61] targeted fear of movement and pain catastrophizing and found a higher return-to-work rate in a 10-week cognitive-behavioral–based physical therapy group compared with standard physical therapy following whiplash injury, whereas George et al. [62] found a decrease in self-reported disability with a six-session fear-avoidance–based physical therapy intervention in patients with back pain. Despite the demonstrated effectiveness of cognitivebehavioral strategies in patients with chronic back and neck pain, limited research has examined the influence of a cognitive-behavioral approach to rehabilitation on pain and disability following spinal surgery. Trials by Christensen

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et al. [63] and Abbott et al. [64] found significantly lower leg pain and improved function with a group behavioral physical therapy intervention and improved functional disability with a brief cognitive-behavioral–based physical therapy program, respectively, in patients after lumbar spinal fusion. However, randomized controlled trials by Ostelo and colleagues [65] and Johansson et al. [66] have failed to show improvements following a behavioral approach to physical therapy in patients after first-time lumbar disc surgery. Nonsignificant findings may be due to excluding empirically supported cognitive strategies, such as cognitive coping and relaxation strategies used by Abbott et al. [64], and not identifying subgroups of patients at risk for poor outcomes. Thus, future rehabilitation interventions targeting fear of movement after spinal surgery should use both cognitive and behavioral strategies to address negative beliefs about movement and the avoidance of physical activity. Incorporating cognitive strategies into rehabilitation also has the potential to ameliorate depressive symptoms postoperatively, which, based on our work and that of others [17,45,67], appears to be an important risk factor along with fear of movement. Specific to this study, higher levels of depressive symptoms at 6-week follow-up predicted increased pain interference and disability and decreased physical health 6 months following spinal surgery. This finding is similar to the work of Sinikallio et al. [45], which demonstrated a strong predictive relation between depressive symptoms in the early postoperative period and poorer outcomes at 1 year following surgery for lumbar spinal stenosis. Robust evidence from the chronic pain literature also supports a significant association between depression and disability and physical functioning [68,69]. Overall, our results strongly suggest that clinically significant symptoms of depression, along with fear of movement, need to be recognized during the early postoperative recovery period and managed appropriately though referral to mental health providers and/or psychologically informed physical therapy (ie, rehabilitation focusing on the management of psychosocial obstacles to recovery of optimal function [70]). Study limitations Several limitations should be considered when interpreting the results of this study. First, although we followed patients prospectively for 6 months after surgery, future studies should continue to examine the relation between preoperative and postoperative fear of movement and postoperative outcomes at 1- and 2-year follow-up. Second, only a limited number of psychosocial variables were investigated in this study. Other variables, such as pain catastrophizing (the tendency to focus on, ruminate, and magnify pain sensations) and self-efficacy (expectations that one can execute a behavior required to produce a desired outcome), have been shown to influence persistent

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pain and disability in patients with various musculoskeletal conditions [54,55,71] and may need to be addressed, along with fear of movement and depression, during postoperative rehabilitation. Furthermore, illness perceptions, such as personal control and illness identity, have been found to predict outcomes in patients with low back pain [72] and other conditions [73,74] and may yet explain some of the variance in postoperative surgical spine outcomes. Finally, our results may not be generalizable to patients having surgery for disc pathology or to patients being treated outside academic institutions. Conclusions The findings from this study provide support for the fearavoidance model in a postsurgical spine population. Early postoperative fear of movement, but not preoperative values, was predictive of increased pain intensity, pain interference, and disability, and decreased physical health at 6 months following surgery. Screening for fear of movement during the first postoperative clinic visit appears warranted to identify patients at risk for poor outcomes. Depressive symptoms in the preoperative and early postoperative period were also predictive of increased disability and poorer physical health, indicating that patients need to be closely monitored for underlying psychological distress that does not acutely improve following surgical intervention. Cognitive and behavioral strategies that have proven effective for chronic back and neck pain may be beneficial for postsurgical patients with high fear of movement and/or depressive symptoms. Interventional trials are needed to determine whether targeted, cognitive-behavioral–based rehabilitation is effective for improving recovery in patients at risk for poor outcomes following spinal surgery for degenerative conditions. References [1] Vlaeyen J, Kole-Snijders A, Boeren R, van Eek H. Fear of movement/(re)injury in chronic low back pain and its relation to behavioral performance. Pain 1995;62:363–72. [2] Lethem J, Slade PD, Troup JD, Bentley G. Outline of a fearavoidance model of exaggerated pain perception: I. Behav Res Ther 1983;21:401–8. [3] Philips HC. Avoidance behavior and its role in sustaining chronic pain. Behav Res Ther 1987;25:273–9. [4] Waddell G, Newton M, Henderson I, et al. A Fear-Avoidance Beliefs Questionnaire (FABQ) and the role of fear-avoidance beliefs in chronic low back pain and disability. Pain 1993;52:157–68. [5] Vlaeyen J, Linton SJ. Fear-avoidance and its consequences in chronic musculoskeletal pain: a state of the art. Pain 2000;85: 317–32. [6] Landers MR, Creger RV, Baker CV, Stutelberg KS. The use of fearavoidance beliefs and nonorganic signs in predicting prolonged disability in patients with neck pain. Man Ther 2008;13:239–48. [7] Grotle M, Vollestad N, Brox J. Clinical course and impact of fearavoidance beliefs in low back pain. Spine 2006;31:1038–46. [8] Somers TJ, Keefe FJ, Pells JJ, et al. Pain catastrophizing and pain related fear in osteoarthritis patients: relationships to pain and disability. J Pain Symptom Manage 2009;37:863–72.

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Early postoperative fear of movement predicts pain, disability, and physical health six months after spinal surgery for degenerative conditions.

The fear-avoidance model offers a promising framework for understanding the development of chronic postoperative pain and disability. However, limited...
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