Table 3

Variables extracted from studies

Variables extractedPotential valuesLevel of measurementIn regression models
1. First author surnameTextNANo
2. Year of publicationYYYYNANo
3. Patient ageNumber ≥18 ≤89ScaleYes
4. Patient sex0=male
1=female
2=unclear or other		NominalNo
5. Symptoms distal to gluteal fold0=no
1=yes
2=unclear		NominalYes
6. A description of the surgical intervention(s)

  • Discectomy

  • Decompression (laminectomy/otomy, facetectomy, foraminotomy)

  • Fusion

  • Arthroplasty (artificial disc)

  • Interspinous device

  • Spinal cord stimulator

  • Other (describe)

  • · Unclear

NANo
7. Treating provider degree0=chiropractic
1=physical therapy
2=TEAM
3=MD/DO
4=other
5=unclear		NominalYes
8. Motion segments remaining following surgery0=0
1=1
2=2
3=3
4=4
5=5 or more
6=unclear		OrdinalYes
9. Spinal implant0=no
1=yes
2=unclear		NominalYes
10. Postsurgical imaging0=no
1=yes
2=unclear		NominalYes
11. Lumbar–SMT0=no
1=yes
2=unclear		NominalYes
12. Lumbar–manual-thrust SMT0=no
1=yes
2=unclear		NominalYes
13. Surgery-to-SMT interval0≤1 year
1≥1 year
2=unclear		NominalYes

  • MD/DO, doctor of medicine or osteopathy; SMT, spinal manipulative therapy; TEAM, traditional East Asian medicine.