Welcome to the Norwich Lumbar Surgery Predictor (NLSP)

NLSP: development version

This Web calculator is designed only for educational purposes and researchers.

The NLSP Web calculator predicts the chance achieving a satisfactory level of disability and pain 1 year after lumbar surgery for disc herniation or spinal stenosis, with or without a single-level fusion. The Web calculator is not a substitute for clinical decision-making and clinicians should make their own clinical judgment on individual patients.


What is satisfactory disability and pain?

Oswestry Disability Index (ODI), back pain, and leg pain and are scored out of 100 (0 = least, 100 = worst).

Satisfactory symptoms are defined as ODI (disability) score of 22 or below, and back pain or leg pain as a score of 30 or below.


How does it work?

Click on “Click here to begin” below to open the NLSP Web calculator. Please enter patient demographic and clinical details.


1.    As a short-cut, if known, add the total ODI score rather than clicking on individual ODI items (questions).

2.    Multiple-joint osteoarthritis (MJOA) is a relatively rare phenotype of osteoarthritis. MJOA diagnosis in the study was by rheumatology consultants using the criteria of ≥5 painful and swollen (effusion) joints with radiographic evidence of osteoarthritis (joints replaced due to osteoarthritis are included in total joints affected). In the original study it was more prevalent and severe in peri- or post-menopausal women (5% prevalence, mean age 70 years) than men of comparable age (1% prevalence, mean age 69 years).



The ODI model categorises patients as low-risk (predicted ODI ≤ 22) or high-risk (predicted ODI > 22).

In the low-risk group 80% achieve acceptable levels of disability or pain compared to 39%–53% in the high-risk group (also see figure at bottom of the NLSP Web calculator page).

Researcher resources

An Excel file enabled with the algorithm can be downloaded here.

A Word file with ODI model outputs and algorithm can be downloaded here.

A Word file with a template preoperative questionnaire can be downloaded here.

Note: As with the Web calculator, the Excel and Word algorithm for external validation is derived from the combined development and validation data in the original study. Please open these files on the respective desktop application, mobile use may not be supported.

Checklists and guidelines for prognostic studies can be found here and here:


The NLSP tool underwent development and temporal validation at one centre and has not been externally validated for use in other centres. The algorithm requires complete information.

This tool is provided 'as is' with no express or implied warranties. The tool is not liable for any direct damages, consequential damages, or lost profits incurred by the user of this predictive tool. The entire risk as to the tool’s quality and accuracy is to those using the tool.

Click here to begin