Acceptance and commitment therapy (ACT) for patients with degenerative spinal disorders and maladaptive psychological processes: an observational study

Introduction

Background

Degenerative spinal disorders are common and frequently cause pain, disability, and impaired health-related quality of life. Spine surgery is an effective treatment option for many patients, but pre-operative optimization is paramount to maximize benefits. Patients living with chronic pain often experience maladaptive psychological processes that include depression, somatization, kinesiophobia, pain catastrophizing, and anxiety (1-5), and prior studies have shown that spine surgery in the setting of maladaptive psychological processes can lead to poor outcomes (6-8). Interventions that can improve maladaptive psychological processes before spine surgery are urgently needed.

Rationale and knowledge gap

Acceptance and commitment therapy (ACT) is a specific form of cognitive-behavioral therapy (CBT) that may be an option for spine surgery patients with maladaptive psychological processes (9,10). ACT uses mindfulness and stress reduction to teach coping and resiliency skills, target psychological flexibility, and promote behavioral changes. The goal of ACT is to help patients find ways to engage in meaningful activities even while experiencing negative thoughts and emotions. ACT encourages patients to understand and manage their pain and psychological distress via six core components: acceptance, being present, cognitive defusion, self as context, values, and committed action. ACT can be provided in-person or virtually online, and can be part of a multidisciplinary approach to pain management. ACT has been shown to improve function, quality of life, and other outcomes among patients living with chronic pain (1-3), but the effects of ACT for patients awaiting spine surgery remain unclear (11,12).

Objective

In this study, we aimed to investigate the preliminary effectiveness of ACT for patients with degenerative spinal disorders awaiting surgery. Our primary objective was to evaluate the effects of ACT at modifying maladaptive psychological processes as measured by multiple patient-reported outcome measures (PROMs), and our secondary objective was to evaluate the effects of ACT on back and leg pain among a smaller subset of patients with these data. We present this article in accordance with the STROBE reporting checklist (13) (available at https://jss.amegroups.com/article/view/10.21037/jss-25-39/rc).

Methods

We performed a retrospective observational study of data that were collected in routine clinical practice at a single academic center (University of Calgary). We obtained local research ethics board approval (Conjoint Health Research Ethics Board at the University of Calgary; approval No. REB23-1320) prior to reviewing patient data. The study conformed to the provisions of the Declaration of Helsinki and its subsequent amendments. Informed consent was not required, and a waiver was granted because this was a retrospective study.

Patient sample

We reviewed data from all consecutive spine surgery patients who were referred for ACT between September 2020 and June 2023. ACT was available as part of a multi-disciplinary optimization program, and referrals were at the discretion of the treating surgeons without any standardized criteria or routine pre-referral screening.

Intervention

ACT was provided to all patients by one of two primary care physicians with specialized training in ACT and complex pain management for patients with degenerative spinal disorders. ACT was provided virtually online via group sessions, and all patients attended an initial ACT education session, followed by four weekly ACT sessions. Online rather than in-person delivery was implemented in 2020 to improve access and reduce attrition. ACT was provided prior to surgery for all patients included in this study.

A standardized ACT curriculum was delivered virtually in the same sequence in 90-minute sessions with the same two clinicians present at all sessions over 4 weeks. Sessions were delivered once per week to allow participants an opportunity to explore the previous week’s content and exercises individually between sessions. Each week, two or more of the six core components of ACT were introduced through conceptual presentation and then practiced with exercises and individual sharing. In the final week, the six ACT core concepts were further integrated, and a values compass and recovery goals were developed and discussed. Exploration and group interaction was encouraged between participants during each session with clear guidelines outlining boundaries, respect, and confidentiality. Group sizes ranged from 8 to 14 participants, with the same individuals attending each session together in sequence. Patients were encouraged to attend all sessions, and were provided with a copy of each session’s content to have as a resource. If a patient missed a single session they were asked to review the sessions content independently. If an individual missed more than one session, they were considered to have not completed ACT and were not included in the analysis for this study.

Outcomes

Patients completed questionnaires for the following PROMs before ACT and at 2 weeks after completing ACT as part of routine clinical practice. Each of these instruments has been extensively validated and shown to have satisfactory psychometric properties:

Patient Health Questionnaire 9 item (PHQ-9) to measure depression: 9 items, scores may range from 0 to 27; higher values indicate greater severity of depression; scores of 10 or greater are consistent with Major Depressive Disorder (14).

Patient Health Questionnaire 15 item (PHQ-15) to measure somatization: 15 items, scores may range from 0 to 30; higher values indicate greater severity of somatization; scores of 10 or greater represent at least moderate somatization (15).

Tampa Scale for Kinesiophobia (TSK) to measure kinesiophobia: 17 items, scores may range from 17 to 68; higher values indicate greater severity of kinesiophobia; scores of 37 or greater represent high kinesiophobia (16).

Pain Catastrophizing Scale (PCS) to measure pain catastrophizing: 13 items, scores may range from 0 to 52; higher values indicate greater pain catastrophizing; scores of 30 or greater represent clinically important catastrophizing (17).

Generalized Anxiety Disorder 7 Item Scale (GAD-7) to measure anxiety: 7 items, scores may range from 0 to 21; higher values indicate greater anxiety; scores of 10 or greater represent clinically important anxiety (18).

Post-Traumatic Stress Disorder (PTSD) Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) (PCL-5) to measure symptoms of PTSD: 20 items, scores may range from 0 to 80; higher values indicate greater PTSD; cut-off scores of 31–33 correlate with provisional PTSD (19,20).

Injustice Experience Questionnaire (IEQ) to measure perceived injustice: 12 items, scores may range from 0 to 48; higher values indicate greater perceived injustice; scores of 30 or greater represent clinically important perceived injustice (21).

Pain Disability Index (PDI) to measure the extent to which aspects of life are disrupted by chronic pain: 7 items, scores may range from 0 to 70; higher values indicate greater pain-related disability; clinically important threshold values have not yet been established (22).

Visual Analogue Scores (VAS; range, 0–10; higher values indicate greater pain) for back and leg pain were available for a subset of patients but were not collected routinely. Measures of general health related quality of life and measures of spine-related disability were not collected.

Statistical analysis

We report discrete variables as counts or proportions, and normally distributed continuous variables as means with standard deviations (SDs). We compared means with two-tailed paired and unpaired t-tests as appropriate. We performed limited subgroup analyses according to dominant symptom of back pain versus other and primary spinal diagnosis of adult spinal deformity (ASD) versus other. PROM scores were standardized as percentages for concurrent presentation in figures.

We implemented minimum clinical important differences (MCIDs) to aid interpretation of treatment effects, and we used PHQ-9 to perform an a priori sample size estimation with an MCID of 5 points (23). In order to achieve 80% statistical power with an alpha of 0.05, 54 patients were required (24). The MCIDs used for the other PROMs were as follows: PHQ-15—2.3 points (25), TKS—6 points (26), PCS-8 point (27), GAD-7—4 points (28), PCL-5—10 points (29), IEQ—7 points (30), PDI—9 points (31), back pain—1.2 points (32), and leg pain—1.6 points (32).

All tests of significance were two-tailed, and P values <0.05 were considered significant. Patients with missing data were excluded from each analysis where appropriate and imputations were not performed. We used IBM SPSS version 26.0.0.1, 2019 (SPSS Inc., Chicago, IL, USA) and Microsoft Excel version 16.73, 2019 (Microsoft Corp., Redmond, WA, USA).

Results

There were 122 patients with degenerative spinal conditions who were referred by 10 surgeons for consideration of ACT from September 2020 to June 2023 (Figure 1). Of these, 46 were excluded from our analyses because they did not complete all ACT sessions (n=14), or because they did not complete baseline (n=1) or follow-up (n=31) PROMs. We note that the baseline scores of those who did not complete follow-up PROMs were similar to those who did (Table S1). An additional 13 patients were further excluded because after they were reviewed by the ACT physicians because they were judged to not require the program because they were found to have minimal psychological comorbidity with scores that were significantly lower than those who were included (Table S2).

Figure 1 Identification of the study cohort: 63 patients with degenerative spinal conditions who underwent ACT. ACT, acceptance and commitment therapy; GAD-7, Generalized Anxiety Disorder 7 item; IEQ, Injustice Experience Questionnaire; PCL-5, Post-Traumatic Stress Disorder (PTSD) Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5); PCS, Pain Catastrophizing Scale; PDI, Pain Disability Index; PHQ-9, Patient Health Questionnaire 9 item; PHQ-15, Patient Health Questionnaire 15 item; PROMs, patient-reported outcome measures; TSK, Tampa Scale for Kinesiophobia.

In total, we included 63 patients with degenerative spinal conditions who completed ACT prior to any surgery (Table 1). Mean age was 58.1 years (SD 14.5 years), mean body mass index (BMI) was 29.6 kg/m² (SD 6.4 kg/m²), 40% were male, 30% were active smokers, and 32% had pre-operative daily morphine equivalent doses (MED) greater than 50 mg. The most common primary symptom at presentation was back pain (35%), followed by radiculopathy (43%), and neurogenic claudication (16%). The most common primary spinal diagnosis at presentation was ASD (40%), followed by lumbar spondylosis without specific deformity or instability (16%), and lumbar degenerative spondylolisthesis (10%). The proportion of patients that had undergone prior spine surgery was 33%. Data completeness for each PROM among included patients was 98–100% (Figure 1). The surgical procedures that patients went on to have after ACT included: lumbar fusion procedures involving 2–4 vertebral bone levels (33%), lumbar fusion procedures involving 5 or more vertebral bone levels (43%), lumbar decompressions or discectomies without fusion (20%), and multilevel anterior cervical discectomy and fusion (4%).

PROMs before and at 2-weeks after ACT are shown in Table 2 and Figure 2. ACT was associated with significant improvements for depression (mean change −3.3, SD 6.5, P<0.001), somatization (mean change −2.9, SD 4.1, P<0.001), kinesiophobia (mean change −6.1, SD 10.8, P<0.001), catastrophizing (mean change −9.9, SD 14.8, P<0.001), anxiety (mean change −2.1, SD 6.2, P=0.007), injustice (mean change −5.5, SD 8.5, P<0.001), and pain disability (mean change −6.4, SD 17.4, P<0.001). ACT was not associated with a significant improvement for symptoms of PTSD (mean change −3.5, SD 14.3, P=0.06). There were no significant differences in pre- or post-ACT scores among the subgroups of patients who presented with versus without a primary symptom of back pain (Table 3), or with versus without a primary spinal diagnosis of ASD (Table 4).

Figure 2 Changes in PROMs among 63 patients with degenerative spinal disorders who underwent ACT. PROM scores were standardized as percentages for concurrent presentation. ACT, acceptance and commitment therapy; GAD-7, Generalized Anxiety Disorder 7 item; IEQ, Injustice Experience Questionnaire; PCL-5, Post-Traumatic Stress Disorder (PTSD) Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5); PCS, Pain Catastrophizing Scale; PDI, Pain Disability Index; PHQ-9, Patient Health Questionnaire 9 item; PHQ-15, Patient Health Questionnaire 15 item; PROMs, patient-reported outcome measures; TSK, Tampa Scale for Kinesiophobia.

The proportions of patients that achieved MCIDs for each PROM are shown in Table 2 and Figure 3. The greatest effects were observed for catastrophizing (52%), somatization (51%), and kinesiophobia (49%), while the smallest effect was for PTSD (27%). Intermediate effects were seen for injustice (41%), depression (37%), pain disability (33%), and anxiety (30%).

Figure 3 Proportions of patients (n=63) with degenerative spinal conditions who achieved the MCID for each PROM after ACT. ACT, acceptance and commitment therapy; GAD-7, Generalized Anxiety Disorder 7 item; IEQ, Injustice Experience Questionnaire; MCID, minimum clinically important difference; PCL-5, Post-Traumatic Stress Disorder (PTSD) Checklist for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5); PCS, Pain Catastrophizing Scale; PDI, Pain Disability Index; PHQ-9, Patient Health Questionnaire 9 item; PHQ-15, Patient Health Questionnaire 15 item; PROMs, patient-reported outcome measures; TSK, Tampa Scale for Kinesiophobia.

VAS back and leg pain were available for 44 patients (70% of the study cohort). Prior to ACT, mean back pain was 7.7 (SD 1.6) and mean leg pain was 6.9 (SD 2.2). Following ACT, mean back pain was 6.4 (SD 2.1) and mean leg pain was 5.5 (SD 2.8), both of which were significant improvements (P<0.001). The proportion of patients that achieved the MCID was 39% for each of back pain and leg pain.

Discussion

Key findings

We performed a retrospective observational study to investigate the preliminary effectiveness of ACT on modifying maladaptive psychological processes among patients with degenerative spinal conditions prior to surgery. Among 63 patients, we found that ACT was associated with significant improvements of depression, somatization, kinesiophobia, catastrophizing, anxiety, injustice, and pain disability. The proportions of patients that achieved the MCID for each of these psychological processes ranged from 27% to 52%, with the greatest effects being observed for catastrophizing, somatization, and kinesiophobia. Effects did not differ among limited subgroups stratified according to primary presenting symptom or spinal disorder. ACT was also associated with achievement of the MCIDs for back pain and leg pain among many patients.

Comparison with similar research

This work adds substantially to a growing body of literature exploring the importance of maladaptive psychological processes among patients with spinal disorders. In a study of 2,031 patients who received surgery for deformity, stenosis, spondylolisthesis, disc degeneration, or disc herniation, Cushnie et al. found that 73% presented with moderate or severe depressive symptoms (5). Maladaptive psychological processes have been shown consistently to have negative prognostic importance, but effective strategies to modify them are limited. For example, Parrish et al. reported a meta-analysis of 7 studies that reported on CBT for patients undergoing lumbar spine surgery, which included data from a total of 531 patients (11). Their results suggested that CBT in comparison to usual care or other treatments was associated with greater improvements in quality of life after surgery, but most of the included studies administered CBT after rather than before surgery. In a separate review of 13 studies, Scarone et al. reported that important remaining knowledge gaps include uncertainty about the optimal timing, intensity, and frequency of CBT, as well as uncertainty about effects of peri-operative CBT on long-term patient-important outcomes (12). Castaño-Asins et al. published a protocol for a planned RCT to investigate ACT versus usual care prior to spine surgery, but results are not yet available (9).

Interventions to modify maladaptive psychological processes have been studied more broadly outside of spine surgery. In a scoping review, Gibson et al. identified 47 studies of patients undergoing any type of surgery and discussed that pain catastrophizing appeared to be at least somewhat modifiable following surgery itself, patient education, physiotherapy, CBT, nursing-directed therapy, and pharmacological treatments (33). In a meta-analysis of 79 studies of patients with chronic non-cancer pain, Schütze et al. found that best evidence supported CBT and specifically ACT, but effects sizes were reported to be of uncertain clinical significance (34). They discussed that interventions should be directed specifically towards patients with demonstrable high catastrophizing scores in order to optimize outcomes. In a prospective study of 203 orthopaedic patients, Sabo et al. found that many orthopaedic surgeons were not able to accurately identify high catastrophizing in the setting of their clinical practice (35).

Strengths and limitations

The most important limitation of this study is its small sample size and preliminary nature. Although this study had sufficient power to detect meaningful differences in PHQ-9, the design involved multiple testing across multiple outcomes, which risks statistical fragility that could lead to spurious or misleading findings (36). Likewise, our power was inadequate to reliably examine subgroups or consider regression for associations with failure to achieve MCIDs. Further studies with larger samples are necessary to validate our findings and increase confidence in our results. Our study did not have a control arm for meaningful comparison to usual care because psychological PROMs were not collected among patients that were not referred for ACT.

The second most important limitation is that this study does not inform about the effects of ACT on outcomes after surgery or durability at long-term follow-up because this study simply reported on the effectiveness of ACT at 2 weeks after versus before the program. It is a major limitation that we did not have data about peri-operative or long-term pain and conventional PROM outcomes, because the goal of ACT for these patients was to optimize their short- and long-term surgical outcomes. This is an important area for future research. It remains unclear to what extent ACT prior to surgery might modify the benefits of surgery itself, and whether ACT prior to surgery is more effective than ACT after surgery during recovery and rehabilitation. Our finding that ACT was associated with improved back and leg pain prior to any surgery suggests the possibility of important treatment interactions, and further research is warranted to explore this in larger sample sizes.

Third, our study is also limited by selection bias. There were no standardized criteria for referral or screening, and the number of patients referred for ACT during the study period is only a small proportion of the total number of patients seen by the surgeons during the study time period. Our finding that only 11% of those who were referred did not actually require ACT due to minimal psychological comorbidity suggests that the surgeons in this study had reasonable positive predictive value for identifying maladaptive psychological processes. Nonetheless, the proportion of those patients who were not referred and could have benefitted is unknown. We were unable to explore reasons for poor compliance among those who were excluded due to failure to complete ACT.

It is also important to consider the possibility of limited generalizability. ACT is not a novel intervention, but administration in the context of our specific multi-disciplinary spine surgery environment was unique and relied on ACT providers with specialized training and experience. Likewise, patients with back pain in the context of ASD represented a large proportion of our included sample, and applicability to patients with other symptoms and/or primary spinal disorders might vary. Patients with ASD are known to experience profound and chronic disability, and our results reflect an increased rate of referral for patients with this pathology by surgeons attempting to optimize this population. Finally, some patients also underwent concurrent opioid deprescribing, obesity management, physiotherapy, and/or bone health optimization, and ACT could interact with any psychological aspects of these treatments.

It remains unknown the extent to which patient might still benefit from ACT if they completed some but not all of the sessions. It could be useful to know the effect of treatment after each individual session, given that different concepts are taught each week followed by an integration week. Our study is limited because we did not collect data to inform about these issues. We also did not collect data about the number of sessions attended by patients who were excluded, and we did not collect outcomes for those who completed some but not all of the sessions.

Implications and actions needed

Our results suggest that ACT can provide substantial benefits to some patients with degenerative spinal disorders, which supports that further implementation of ACT in clinical practice is appropriate and that further research is warranted. Rates of achieving MCIDs varied from 27% to 52%, which corresponds to numbers needed to treat (NNT) of approximately 1 in 4 to 1 in 2. These findings are very encouraging, but they also highlight that many patients did not experience improvement. Further research is warranted to investigate reasons for non-response and whether other interventions could help these patients. Ultimately, well-designed randomized controlled studies are necessary to reliably compare the efficacy and effectiveness of ACT versus usual care, and outcomes should include general health related quality of life and long-term measures of spine-related disability after surgery in addition to psychological PROMs. Efforts to develop standardized protocols for screening and referral could minimize selection bias and help identify those patients who might benefit most, which could inform healthcare resource distribution.

The use of virtual delivery formats also warrants further attention. ACT is an intervention which requires both specialized expertise to provide and substantial commitment by patients to participate. Virtual delivery may improve accessibility and adherence, which could enhance the practicality and scalability of implementing ACT in broader clinical settings.

Conclusions

Among selected patients, ACT prior to spine surgery may be associated with significant improvements for many maladaptive psychological processes. These results suggest that implementation of ACT in clinical practice could be appropriate and that further research to understand effects on outcomes after surgery is warranted.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jss.amegroups.com/article/view/10.21037/jss-25-39/rc

Data Sharing Statement: Available at https://jss.amegroups.com/article/view/10.21037/jss-25-39/dss

Peer Review File: Available at https://jss.amegroups.com/article/view/10.21037/jss-25-39/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-25-39/coif). W.B.J. reports consulting fees from Stryker, Cerapedics, J&J MedTech and speaker fees/honoraria from Stryker, Cerapedics, J&J MedTech, Medtronic; F.N. reports grants from Medtronic, DePuy Synthes, Stryker and consultancy fees from DePuy Synthes and speaker fees/honoraria from AO Spine North America; A.S. reports teaching fee from Strkyer; G.S. reports grants from AOSpine and Alberta Spine Foundation, speaker fees/honoraria from Medtronic Canada, and shareholder for Torus Biomedical Solutions Inc.; E.S. reports employment from Caleo Health. D.E. reports employment from Caleo health. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the institutional review board of the University of Calgary (REB23-1320) and individual consent for this retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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