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Surgery complexity
For blood loss estimation 2
3.0%
Low risk
Low High
95% CI: —
Kernel density estimate — Dataset
No complication
Complication
Model notes: Defaults reflect cohort averages (BMI 27 kg/m², CRP 1.2 mg/L, blood loss 200 mL, no comorbidities). BMI contributes only for units above 25. Logistic regression coefficients: BMI OR 1.07/unit above 25; CRP OR 1.01/mg/L; diabetes type 2 OR 1.94; CHF OR 4.56; prior lumbar surgery OR 1.96; dural tear OR 1.87; blood loss OR 1.11/100 mL. Intercept calibrated to ~3% cohort prevalence. 1
1 Bauer DE et al. Risk factors for major wound complications requiring surgical revision after lumbar spine surgery — retrospective cohort, n = 4,067 (2017–2023). This calculator is provided for research and educational purposes only. It reports population-level estimates from a reference cohort and is not intended to predict outcomes for, or guide treatment decisions about, individual patients.

2 Farshad M, Bauer DE, Wechsler C, Gerber C, Aichmair A. Risk factors for perioperative morbidity in spine surgeries of different complexities: a multivariate analysis of 1009 consecutive patients. The Spine Journal, 2018. DOI: 10.1016/j.spinee.2018.02.003 — Category I: 209 mL, Category II: 403 mL, Category III: 612 mL mean intraoperative blood loss.
Surgical complexity — lumbar procedures: ²

Category I — Lumbar microdiscectomy · Lumbar posterior decompression · Lumbar posterior instrumentation (pedicle screws) · Lumbar kyphoplasty · Lumbar vertebroplasty

Category II — Posterior lumbar interbody fusion (PLIF) · Transforaminal lumbar interbody fusion (TLIF) · Sacral-pelvic instrumentation

Category III — Lateral lumbar interbody fusion (LLIF) · Anterior lumbar interbody fusion (ALIF) · Lumbar disc prosthesis · Lumbar hemi-/corpectomy