Does Symptom Duration Correlate Negatively With Outcome After Posterior Lumbar Interbody Fusion for Chronic Low Back Pain?
Bibliographic record
Abstract
STUDY DESIGN: Original report. OBJECTIVE: To investigate the putative negative correlation between the duration of symptoms (DOS) and outcome after surgery for chronic low back pain (CLBP). SUMMARY OF BACKGROUND DATA: Posterior lumbar interbody fusion (PLIF) is a well established treatment for CLBP. Anecdotally, a prolonged DOS is associated with a poor prognosis for recovery of CLBP. In one recent study, a DOS greater than 3 years predicted a poor prognosis for subsequent clinical improvement with CLBP. METHODS: Patients (n = 209) underwent PLIF for CLBP who had proven unresponsive to nonoperative management for at least 6 months. A wide variety of physical and mental outcome scores were simultaneously assessed pre- and after surgery: i.e., the Oswestry Disability Index (ODI), SF-36 body score, SF-36 mental score, Visual Analogue Score (VAS) for back pain, VAS for leg pain, Hospital Anxiety Score (HAS), and Hospital Depression Score. RESULTS: Despite a prolonged mean DOS of 84.3 ± 6.6 months, there was a significant postoperative improvement in all 7 outcome scores after PLIF. Significant improvement occurred in 181 patients (i.e., 86.6%) and was sustained at 51.6 ± 12.0 months follow-up. No significant correlation was found between DOS and any outcome score (ODI: rs = 0.013, P = 0.877; SF-36 bodily pain: rs = 0.013, P = 0.87; VAS for back pain: rs = 0.038, P = 0.656; VAS for leg pain: rs = 0.086, P = 0.310; HAS: rs = 0.511, P = 0.056; Hospital Depression Score: rs = 0.056, P = 0.509, or SF-36 mental score rs = 0.007, P = 0.935). No arbitrary DOS "cut-off" was found for which significantly different outcomes were recorded either side of the cut-off; or for which a significant correlation was revealed either side of the cut-off. Finally, no significant partial correlation was found between DOS and any outcome score after controlling for pain severity (VAS(back pain)) before surgery. There were no significant differences in terms of age, sex, or DOS between those with improved ODI scores less than 10 compared with those with improved ODI scores greater than 10. CONCLUSION: The putative negative correlation between DOS and outcome was not observed under any analysis in our study. PLIF procured a rapid and sustained improvement in CLBP, even where the DOS was excessively prolonged; and even after having allowed for pain severity. Symptom chronicity, therefore, does not represent a poor prognostic indicator for CLBP outcome after PLIF: PLIF should be considered irrespective of DOS. Because DOS and pain severity are likely mediators of "central sensitization," the hypothesis that central sensitization may be prevalent in CLBP patients selected for PLIF is therefore questioned.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.003 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".