Baseline Patient Risk Profile
Every fusion outcome model starts from a preoperative risk snapshot.
- 4: Key risk domains (smoking, distress, levels, age)
- ~92%: Baseline success rate (ideal low-risk patient)
- 5–35%: Non-union incidence (depends on risk burden)
- 2 sliders: Model inputs used here (smoking + distress)
Why preoperative screening matters
Risk factors compound long before the incision is made.
What the simulator tracks
Smoking, distress, and fusion levels drive the prediction.
Reading the metrics panel
Success, healing rate, complication risk, and category update live.
Smoking Status & Bone-Healing Suppression
Nicotine is one of the strongest modifiable predictors of fusion failure.
- 2–3×: Non-union risk, smokers (higher than non-smokers)
- ~50%: Osteoblast activity drop (under nicotine exposure)
- 4–6 wks: Recommended cessation (before elective fusion)
- ≈ non-smokers: Success rate, quitters (if cessation sustained)
How nicotine impairs fusion
Vasoconstriction starves the graft site of oxygen and nutrients.
Osteoblast suppression
Bone-forming cells proliferate slower under nicotine exposure.
Clinical counseling impact
Preoperative cessation programs measurably improve fusion rates.
Psychosocial Distress & Pain Catastrophizing
Mental health status predicts outcome nearly as strongly as biology.
- +15–20%: High-distress non-union risk (vs low-distress patients)
- PCS score: Catastrophizing screen (pain catastrophizing scale)
- ~20–30%: Depression prevalence (in fusion candidates)
- measurable: Prehab counseling benefit (improves reported outcomes)
Distress and pain perception
High catastrophizing amplifies perceived pain after surgery.
Biological stress pathways
Chronic stress hormones can slow tissue repair processes.
Screening before surgery
Validated questionnaires flag patients needing extra support.
Number of Levels Fused
Each additional fused level adds mechanical stress and healing burden.
- ~90–95%: Single-level success (lowest complexity case)
- ~70–80%: Multi-level (3–4) success (higher construct demand)
- 2–3×: Complication rate, 4-level (vs single-level fusion)
- +45–60 min: Operative time per level (added surgical exposure)
Mechanical load distribution
More segments mean more junctions that must each fuse solidly.
Blood supply and exposure
Longer constructs mean more tissue disruption per surgery.
Cumulative non-union risk
Failure at any single level can compromise the whole construct.
Overall Outcome Probability Estimate
Combining all risk factors yields one actionable success estimate.
- ~95%: Best-case combined success (non-smoker, low distress)
- <20%: Worst-case combined success (smoker, high distress, multi-level)
- 4 metrics: Model output (success, healing, risk, category)
- shared decision: Clinical use (informs surgical counseling)
Reading the outcome gauge
The needle sweeps toward the combined success probability.
Modifiable vs fixed factors
Smoking and distress can improve; anatomy usually cannot.
Using this for counseling
Risk estimates help patients and surgeons set expectations.