Prediction Model Shows Accuracy in Estimating Outcomes After Low Back Surgery

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A multivariable prediction model for outcome after lower back surgery may reliably predict 12-month improvements.

A multivariable prediction model for outcome after lower back surgery taking into account comorbidity history, back pain score, and motor and physical deficits may predict 12-month improvements in physical disability, the ability of the patient to return to work, major complications, readmissions, and inpatient rehabilitation requirements reliably, according to a study published in Neurosurgical Focus.

In this prospective 12-month analysis of patient-reported outcomes, investigators evaluated 1803 consecutive patients who underwent spine surgery for degenerative lumbar diagnoses.

They collected electronic medical record data on patients’ comorbidities, individual surgery details, and perioperative course. Patient interviews and health assessments were conducted at baseline as well as 3 and 12 months after surgery.

Participants were randomly selected for model development (80%) and model validation (20%). The model coefficients included smoking history, comorbidity history (eg, atrial fibrillation, chronic obstructive pulmonary disorder, arthritis, diabetes, osteoporosis), body mass index, sex, symptoms present for >1 year, and chronic back pain.

All patient-reported outcomes improved after surgery (Oswestry Disability Index at baseline, 50.4% vs at 12 months, 29.5%; P <.001). A total of 121 patients (6.6%) experienced complications, and 108 patients (5.9%) required readmission within 30 days of intervention. In addition, 188 patients (10.3%) were discharged to inpatient rehabilitation, 449 patients (24.9%) had an unplanned outcome, and 1630 (88.9%) were able to return to work.

The goodness of fit of the model (estimated with R2) was 0.51 and 0.47 for development and validation, respectively, suggesting that approximately half of the observed outcome variations were explained by the prediction model. The area under the curve values were between 0.72 and 0.84 for readmission, complications, inpatient rehabilitation, and ability to return to work and between 0.79 and 0.84 for unplanned postoperative outcome.

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The model used in this study was applied to patients from a single center and may not generalize to other patients evaluated at different centers.

“The predictive models we present here may have tremendous value as real-world decision support tools for patients, providers, hospital systems, and payers alike,” concluded the study authors, adding “Patients are now empowered to sit down with their physician and have a concrete discussion about expectations after surgery that is tailored to their particular risk profile.”

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McGirt MJ, Sivaganesan A, Asher AL, Devin CJ. Prediction model for outcome after low-back surgery: individualized likelihood of complication, hospital readmission, return to work, and 12-month improvement in functional disability. Neurosurg Focus. 2015;39(6):E13.