Lumbar Fusion or Non-operative Care for Treatment of Presumed Discogenic Pain
Condition: Low Back Pain
MeSH terms: Low Back Pain
Study type: Interventional

Summary: 
      Title and abstract

      1 a. Title: Lumbar fusion or non-operative care for treatment of presumed discogenic pain.

      A randomized study.

      1 b. Structured summary:

      Authors: B. Nyström, B. Schillberg, E. Svensson, T. Stiles.

      Corresponding author: Bo Nyström, Clinic of Spinal Surgery, Strängnäs, Sweden. e-mail
      address: pgbo.nystrom@gmail.com

      Background: At present there is no clear evidence that surgical treatment by fusion operation
      is more advisable than non-surgical treatment in patients suffering from unspecific chronic
      low back pain (CLBP). By personal experience a subgroup among the CLBP patients is selected,
      possibly representing patients with pain from a motion segment/disc, thus making patient
      selection more specified. Furthermore, selection of level to fuse based on radiological
      findings has not been found reliable. Therefore a mechanical provocation test has been
      developed at the clinic. The aim of this randomized study was to compare the outcomes in pain
      and pain related functions perceived by this specific subgroup of CLBP patients following
      fusion surgery with those following non-surgical treatment.

      Methods: Patients with a specified symptomatology and specified clinical signs at examination
      were recruited and randomized to either type of treatment, non-surgical (NS) including
      cognitive-behavioral therapy and physiotherapy (37 pat.) or surgical (S), including the same
      cognitive-behavioral therapy and physiotherapy as in the NS group plus fusion surgery (37
      pat.). All patients were thoroughly investigated before start of the study and at follow-up
      one year after treatment. The outcomes perceived by the patients were assessed on the
      validated questionnaires Oswestry Disability Index (ODI), Roland-Morris, Balanced Inventory
      for Spinal Disorders (BIS), Short-Form-36 (SF-36) and Euro-Quol (EQ-5D).
    

Detailed description: 
      1. a. Title: Lumbar fusion or non-operative care for treatment of presumed discogenic pain.

           A randomized study.

           Introduction

           Background and objectives:

        2. a. Only two out of five existing randomized studies comparing results from fusion
           surgery for chronic low back pain (CLBP) with results from conservative treatment have
           reported the results from surgery to be better. Systematic review of these trials also
           found methodological concerns. At present, therefore, there is no clear evidence that
           surgical treatment is more advisable than non-surgical treatment in patients suffering
           from unspecific CLBP.

      2 b. The investigators hypothesis is that a/ there exists a specific identifiable subgroup of
      patients within the CLBP group in whom the pain emanates from the disc, and that b/ patients
      in this subgroup may be selected based on thorough symptom analysis, and c/ that the actual
      disc may be localized, not by radiological methods or discography, but by mechanical testing
      procedures, making pain reduction possible by a fusion operation at that level.

      Methods

      Trial design:

      3 a. A RCT with parallel group design with pre- and post-treatment data.

      3 b. No changes were made after trial commencement.

      Participants

      4 a. Inclusion criteria: 18 to 65 years, with pronounced low back pain for at least one year
      and having tried ordinary physical therapy without improvement and being on sick leave at
      least 50 %. They should not have had any prior fusion operation but may have had surgery for
      e.g. a disc herniation.

      4 b. Eligible outpatients at the Clinic of Spinal Surgery, Strängnäs, Sweden, were informed
      about the study and those who consented to participate were included, the other received
      ordinary treatment outside the study.

      Data were collected at the Clinic of Spinal Surgery, Strängnäs, Sweden. Interventions

      5. A percutaneous mechanical provocation test was developed to obtain information regarding a
      possibly painful segment. Local disc injections were also performed to analyse the pain
      response at needle contact with the disc, at injection into the disc with saline or local
      anaesthetics blind for the patients and also the pain situation following local anaestetics
      into the disc, discoblock.

      Further, an open mechanical provocation test was developed to analyse the location of a
      possibly painful disc. Operation by posterior lumbar interbody fusion was performed using
      microsurgical technique and autologous bone. Internal fixation was used.

      Patients in both groups, the surgical (S) and the non-surgical (NS) group, were all treated
      by formal physiotherapy at a five days stay at the Clinic and instructed to continue their
      training at home according to the lines given at the Clinic. Patients in both groups were
      similarly treated individually by cognitive-behavior therapy at seven occasions.

      Outcomes

      6 a. The primary outcome was back pain, assessed by the patients on the BIS and on a VAS
      before treatment and at follow-up one year after treatment as well as the perceived change in
      pain.

      Secondary outcomes were pain related functions assessed on the ODI, the Roland-Morris, and
      the BIS questionnaires. Health related quality of life was also assessed as a secondary
      outcome measure, by using the SF-36 and EQ-5D questionnaires.

      6 b. No changes in trial outcomes were made during the study.

      Sample size

      7a. The sample size calculation was performed before study start by the statistician (ES). It
      was based on previous knowledge of outcomes from a Swedish cross-sectional study (surgery vs
      physiotherapy) in which the proportions patients with improvement were 63% and 29%,
      respectively. Assuming similar results of improvements a total sample size of 66 (33+33) will
      detect such a difference with the statistical power of 80%.

      7 b. Interim analysis did not occur.

      Randomization. Sequence generation.

      8 a and b. A randomization scheme balanced for female/male, as well as for
      surgery/non-surgery patients was performed by using random permuted blocks of 20 (10 females
      and 10 male) patients in order to reduce predictability. The permutation blocks were randomly
      chosen. Two sets of closed envelopes in numbered orders, one set for males and one for
      females, with either message "operate" or "do not operate" were delivered to the clinic by
      the statistician not involved in the treatment of the patients.

      Allocation concealment mechanism

      9. The patients were consecutively included in the study according to the randomization
      envelopes.

      Implementation

      10. A statistician not involved in the treatment of the patients generated the random
      allocation sequence. The surgeon enrolled the participants and an anaesthesiology nurse at
      the clinic performed the practical assignment, i.e. opened the closed envelopes in
      consecutive order.

      Blinding

      11 a. In accordance with the treatment alternatives the participants and the care givers
      could not be blinded to group assignment.

      11 b. Patients in both groups, the surgical and the non-surgical, received equal
      cognitive-behavioral treatment and physiotherapy. Besides, patients in the surgical group
      were operated by spinal fusion.

      Statistical methods

      12 a and b. The outcome variables are assessed on rating scales that generate ordered
      categorical data. Characteristic features are the ordered structure with lack of information
      regarding size and inter-categorical distances. Non-parametric rank-based statistical methods
      that take account of these limited mathematical properties of ordered categorical data have
      been used for description and analysis. Frequency distribution, proportions, bar charts,
      median and quartiles are used for statistical description of cross-sectional data.
      Statistical analysis of difference in outcomes assessed by transitional scales in the BIS by
      the two groups of patients was performed by the Wilcoxon-Mann-Whitney test. Statistical
      evaluation of change in the paired assessments made before treatment and on the follow-up
      occasion was made by a statistical approach developed for paired ordinal data that provides
      measures of systematic change in common for the group and additional measure of individual
      variability. The measures and the 95% confidence intervals of systematic change in position
      (RP), and in concentration (RC), and the measure of individual variability (RV) will be
      calculated as well as the differences in these measures between the two treatment groups.
      This approach has been found to have a high power of detecting differences in small samples.

      Results

      13. All patients in the surgical as well in the non-surgical group received the allocated
      treatment. All patients in both groups were seen at follow-up.

      Recruitment

      14 a. Recruitment started July 4, 2007 and ended when the last patient was included in the
      study at March 28, 2011.

      The follow-up took place from Oct. 21, 2008 to June 27, 2012.

      14 b. The trial was performed as planned.

      Numbers analysed

      16. The analysis was carried out on the complete groups of 37 patients in each group and no
      missing patients.

      Outcome and estimations

      17 a and b. The material is not fully analysed yet.

      Ancillary analysis

      18. None.

      Harms

      19. There were no surgical complications, no neurological deterioration and no device
      failures. Five of the 37 patients in group S had defect bone healing and were re-operated by
      anterior fusion at the same level, one patient had anterior fusion at a new level and in 3
      patients the fixation screws were extracted due to local pain.

      Comment

      Limitations:

      20. There was a rather small sample size because of difficulties in recruiting eligible
      patients, but a good research team and the choice of appropriate statistical analysis shows
      the power of this study.

      Generalizability

      21. The investigators regard the results generalizable, provided that the patients and the
      level to fuse being selected according to the same criteria as in the present study.

      Interpretation

      22. Based on the results from existing randomized studies comparing fusion surgery with
      conservative treatment in patients suffering from CLBP it has not been evident that surgery
      is advisable. However, in previous studies the symptoms of the patients selected has been
      described simply as "chronic low back pain". The patients in the investigators study were
      selected based on a more specific symptom analysis. Furthermore, in previous studies the
      level to fuse has been chosen based on radiological findings whereas a mechanical provocation
      tests is used in the present study. Two of the previous studies stated the importance of
      cognitive-behavioral therapy in CLBP patients, resulting in equally good results as following
      fusion surgery. To study the specific effect of surgery, therefore, both groups in the
      investigators study received quite the same treatment with cognitive-behavioral therapy and
      physiotherapy, the difference between the two groups being that one group also received
      surgery.

      Other information

      Registration:

      23. The study protocol was approved by the Regional Ethics Committee, Stockholm (reference
      number 2007/598-31/4). In accordance with the Declaration of Helsinki, all patients were
      thoroughly informed concerning all parts of the study, both verbally and in written text, and
      gave their written informed consent.

      24. The full trail protocol can be accessed via Bo Nyström, Clinic of Spinal Surgery,
      Strängnäs, Sweden.

      25. The study had no funding support.
    

Intervention name(s): Lumbar Fusion Surgery; Physiotherapy; Cognitive behavioral therapy
Intervention type(s): Procedure; Other; Other
Intervention description(s): Interbody fusion with fixation; Examination by physiotherapist, motivation of the patient, training in body awareness, physical activity/Qigong, training in water, outdoor pole work, circle training, stabilization training, massage, stretching, lessons and practice in ergonomics.; Individual and group lessons performed by psychologists.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment