G1.1. Strength of Evidence Assessment

The EPC strength of evidence (SOE) rating for each body of evidence was assessed as high, moderate, low, or insufficient, using the approach described in the AHRQ Methods Guide,² based on study limitations, consistency, directness, precision, and reporting bias.

• Study Limitations (low, moderate, or high)
• Directness (Direct or Indirect)
• Consistency (Consistent, Inconsistent, or Unknown)
• Precision (Precise or Imprecise)
• Reporting Bias (Suspected or Undetected)

These criteria were applied regardless of whether evidence was synthesized quantitatively or qualitatively. The I² statistic was used to help assist consistency in pooled analyses; The confidence intervals surrounding effect estimates were reviewed for clear benefit, no effect, and clear harms to aid in assessing precision. We considered evidence from both randomized trials and nonrandomized studies in determining strength of evidence with greater weight given to randomized studies. Strength of evidence ratings reflected our confidence or certainty in the findings. Strength of evidence was considered insufficient when evidence was lacking, sparse, or too conflicting such that we were unable to draw conclusions. SOE was initially assessed by one researcher and confirmed by a second. Based on the assessments for each domain, an overall strength of evidence grade was assigned to each outcome, as defined in the AHRQ Methods Guide.²

Table G-1. Strength of evidence definitions (MS Word, 39K)

G2.1. Strength of Evidence Tables

Key Questions 1 and 10 had no eligible studies to assess.

Table G-2. Key Question 2: surgery versus conservative treatment (MS Word, 55K)

Table G-3. Key Question 3: surgery versus physiotherapy versus collar (MS Word, 48K)

Table G-4. Key Question 4: surgery (laminoplasty) plus add-on therapy versus surgery alone (MS Word, 52K)

Table G-5. Key Question 4: surgery (ACDF) plus add-on therapy versus surgery alone (MS Word, 51K)

Table G-6. Key Question 5. anterior versus posterior procedures in ≤ 2 levels in patient with radiculopathy (MS Word, 125K)

Table G-7. Key Question 6: anterior versus posterior procedures in ≥ 3 levels (MS Word, 152K)

Table G-8. Key Question 7: laminectomy with fusion vs. laminoplasty (MS Word, 124K)

Table G-9. Key Question 8: C-ADR versus ACDF strength of evidence – single-level interventions (MS Word, 472K)

Table G-10. Key Question 8: C-ADR versus ACDF strength of evidence – 2-level interventions (MS Word, 194K)

Table G-11. Key Question 8: C-ADR versus ACDF strength of evidence – mixed level (i.e., 1, 2, or 3) interventions (MS Word, 61K)

Table G-12. Key Question 9: Interbody graft material or device – standalone cage versus plate and cage (MS Word, 137K)

Table G-13. Key Question 9: Interbody graft material or device – titanium cage/titanium-coated PEEK cage versus PEEK cage (MS Word, 69K)

Table G-14. Key Question 9: Interbody graft material or device – autograft, allograft, other osteogenic materials (MS Word, 111K)

Table G-15. Key Question 11: Prognostic utility of MRI findings (MS Word, 92K)

Table G-16. Key Question 12: Diagnostic accuracy of imaging assessment (MS Word, 50K)

Table G-17. Key Question 13: Intraoperative neuromonitoring (MS Word, 47K)