What should be checked before relying on a WPI figure?
Check maximum medical improvement, the body area, objective findings, the NSW Guideline chapter and any NSW modification before relying on a percentage.
Can this page calculate your percentage?
No. WPI depends on an assessor, maximum medical improvement, objective findings and the NSW Guidelines. This page is general information only.
Permanent impairment assessment
How permanent impairment is assessed for Disc bulge, disc prolapse and disc herniation
Disc bulge or prolapse WPI is not based on the MRI wording alone. The assessor needs to connect the disc finding to the clinical picture, decide whether radiculopathy exists, and then apply the NSW DRE spine method and any relevant surgery modifier.
What injuries can happen to this body part?
- Disc bulge, protrusion, extrusion, sequestration or annular tear described on MRI/CT
- Disc prolapse causing nerve-root compression, radiculopathy or sciatica-type symptoms where signs match the level
- Recurrent disc prolapse after surgery or residual post-operative disc/scar findings
- Disc degeneration or multilevel findings where causation and apportionment may be disputed
- Back or neck pain without objective neurological signs, which may still affect capacity but is not the same as ratable radiculopathy
Symptoms and findings that matter
- Whether the disc finding is a bulge, protrusion, extrusion, sequestration or post-surgical change
- Clinical signs matching the affected nerve root and side
- Whether symptoms are single-level, recurrent or multilevel
- Surgery history, residual symptoms and Table 4.2 relevance
- Pre-existing degeneration and whether apportionment is raised
What investigations are usually relevant?
- Treating specialist report and final impairment assessment at maximum medical improvement
- Imaging, pathology, audiology, ophthalmology, respiratory, nerve or functional testing that fits the body system
- Operative reports, discharge summaries, rehabilitation records and objective clinical measurements where relevant
How WPI is assessed for this body part
- Disc bulge or prolapse WPI is not based on the MRI wording alone. The assessor needs to connect the disc finding to the clinical picture, decide whether radiculopathy exists, and then apply the NSW DRE spine method and any relevant surgery modifier.
- Assessment source: NSW Guidelines Chapter 4, including the warning that disc protrusions may exist without injury-related impairment, and AMA5 spine tables where adopted.
- The assessor should explain maximum medical improvement, the body-system chapter, the method selected, any NSW modification, and why the objective findings fit that method.
How movement affects the assessment
- Back movement limits can show function, but the NSW spine chapter excludes the ROM model for WPI.
- Reduced bending or sitting tolerance is important for work capacity but does not convert a disc bulge into a fixed WPI percentage.
NSW spine assessment rules
DRE methodThe NSW spine chapter says spinal impairment is evaluated using diagnosis-related estimates (DREs).
DRE vs ROMAMA5 contains a ROM model in some contexts, but the NSW spine chapter says the ROM model should not be used for NSW spine WPI. Movement observations may still help describe DRE clinical findings, such as asymmetric movement.
ImagingImaging can support the diagnosis, but imaging alone is insufficient for a DRE category except for spinal fractures.
RadiculopathyRequires objective neurological findings. Radiating pain, pins and needles or a scan report alone are not the same as radiculopathy.
Electrodiagnostic testingEMG/NCS may help clinicians investigate symptoms, but SIRA says electrodiagnostic verification of radiculopathy should be disregarded when placing the worker into a DRE category.
Surgery modifiersSIRA Table 4.2 gives public NSW modifiers for relevant spinal surgery scenarios; the operation itself must fit the Guideline wording.
Spine DRE category concepts, without guessing percentages
DRE IUsually no significant clinical findings. Do not use this guide to infer a percentage without the relevant AMA5 table.
DRE IIUsually minor objective findings, resolved radiculopathy, non-verifiable radicular complaints, or structural findings that fit the table.
DRE IIIOften relevant where radiculopathy is present or where the table criteria otherwise place the worker in category III.
DRE IVOften relevant where alteration of motion segment integrity, fusion-type criteria or higher-grade fracture criteria apply, depending on the region and NSW method.
DRE VCan involve radiculopathy plus alteration of motion segment integrity, but NSW modifies post-fusion radiculopathy treatment through Table 4.2.
NSW radiculopathy criteria, in practical terms
Criteria countThe NSW Guidelines generally require two or more criteria, with at least one major criterion, before radiculopathy is concluded.
Reflex, motor or sensory findingsLoss or asymmetry of reflexes, anatomically localised weakness, or reproducible sensory impairment can be relevant when they fit the nerve root distribution.
Nerve tension, wasting and imagingPositive nerve root tension, muscle wasting/atrophy, and imaging consistent with the clinical signs can also be relevant.
Pain aloneRadicular pain or sensory symptoms that follow an anatomical pathway but cannot be verified by neurological findings do not alone constitute radiculopathy.
SIRA Table 4.2 public spine surgery modifier rows
Spinal surgery with residual symptoms and radiculopathyCervical 3% WPI, thoracic 2% WPI, lumbar 3% WPI, subject to the Guideline criteria.
Second and further levelsAdd 1% WPI for each additional level in cervical, thoracic or lumbar regions, where the Guideline permits it.
Second operation2% WPI in cervical, thoracic or lumbar regions, where the Guideline permits it.
Third and subsequent operations1% WPI each in cervical, thoracic or lumbar regions, where the Guideline permits it.
Practical WPI examples
- A person can have a disc bulge on MRI and no ratable WPI if the clinical findings do not fit the impairment criteria.
- A disc prolapse with consistent nerve-root signs is a stronger WPI issue than a scan-only finding.
- Surgery can change the method, but the operation name alone does not set the percentage.
Evidence checklist
- A clear diagnosis and the body area being assessed
- Records showing the condition has reached maximum medical improvement, if that is the issue
- Specialist reports, imaging reports and treating notes relied on by the assessor
- Objective findings on examination, not only symptoms described by the injured person
- A work and treatment chronology explaining the injury, treatment, surgery and recovery path
- Any previous injury, degeneration, congenital issue or non-work cause that needs apportionment considered
- MRI/CT report, specialist notes, neurological examination, operative reports and treatment chronology
What usually does not increase WPI
- Assuming a scan result automatically gives a WPI percentage
- Confusing pain, disability or inability to work with permanent impairment
- Ignoring maximum medical improvement before arranging an assessment
- Using an AMA5 table without checking whether the NSW Guidelines modify or replace it
- Double counting the same impairment through two methods when the Guidelines require one method
- Treating every disc bulge as a compensable permanent impairment
- Ignoring asymptomatic or pre-existing disc findings
Assessment source
Assessment source: Assessment source: NSW Guidelines Chapter 4, including the warning that disc protrusions may exist without injury-related impairment, and AMA5 spine tables where adopted.
This section is source-backed general information. It is not a WPI assessment and is not legal advice.
- SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment: Source for the NSW assessment framework, MMI, AMA5 adoption, NSW modifications and exclusions.
- SIRA spine chapter: Source for NSW spine assessment rules, DRE method, radiculopathy criteria and surgery modifiers. The NSW spine chapter excludes the ROM model.
- SIRA DRE definitions of clinical findings: Source for clinical findings used to place a spine condition into a DRE category.
- SIRA Table 4.2 spine surgery modifiers: Public NSW surgery modifier rows for DRE categories following spine surgery.
- SIRA Table 4.2 interpretation note: Source for how surgical modifiers following spine surgery should be read and applied.
Related injury and claim pages
- Common injury evidence hub
- Work injury claims NSW
- Claim process
- Compensation and entitlements
- Ask about an impairment issue
- NSW Injury Claim Evidence, Documents and Templates - This library helps injured people organise incident, medical, income, correspondence and daily-impact records into a clear working file, without presenting any checklist or template as an official form.
- NSW Injury Claims by Location - NSW Injury Claims accepts enquiries from across NSW. The claim pathway depends on how the injury happened, while phone, online and electronic document handling can make an initial enquiry possible without creating a false impression of premises in every region.
- Radiculopathy WPI Assessment NSW - Spine permanent impairment assessment guide with NSW Guideline source notes.
Need a practical claim check?
If an impairment percentage, medical assessment or insurer decision is affecting your NSW injury claim, send the decision or report for a practical review. This is general information only and does not guarantee any result.
Request a free claim checkAssessment scope for Disc Bulge and Disc Prolapse WPI Assessment
The assessment scope for Disc Bulge and Disc Prolapse WPI Assessment should be stated precisely before any percentage is considered. The file should identify whether that label describes the primary diagnosed condition, a symptom of another injury, a regional overview or one component of a broader impairment. Findings from another body area or diagnosis should not be transferred without explanation. The report should connect the stated condition to the correct NSW Guideline chapter, objective findings, treatment history and any permitted combination or apportionment method. This distinction is particularly important where similar page labels cover different clinical questions.
- Confirm the diagnosis and body area being assessed as Disc Bulge and Disc Prolapse
- Separate condition-specific findings from overlapping symptoms or injuries in another body area
- Check that the selected NSW Guideline chapter and method match the condition actually assessed
- Explain any combination, apportionment or exclusion rather than relying on the page label alone
Start with maximum medical improvement
Permanent impairment should generally be assessed when the condition is stable and unlikely to change substantially in the next year. Treatment, surgery and rehabilitation history may affect whether the timing is appropriate.
Use the NSW Guidelines first
The NSW Guidelines adopt AMA5 in many areas, but NSW modifications prevail. Do not assume an AMA5 table applies without checking the NSW chapter and any public SIRA clarification.
Keep the assessment practical
A useful assessment file separates diagnosis, objective findings, surgery history, work capacity issues, apportionment questions and the body-area method used by the assessor.
Ask about an impairment issueDocuments and records
Injury evidence to organise early
The useful records depend on how the injury happened, when symptoms were recorded and how treatment or work capacity changed.
- Date, location and short description of the injury event
- Medical certificates, reports, scans, treatment records or hospital documents
- Employer, insurer, police, incident or venue records where relevant
- Photos, witness details, dashcam or other supporting material if available
- Income, superannuation, work capacity or leave records where relevant
- Letters, emails, claim numbers and decisions already received
Common questions
Injury evidence questions
Short general answers only. The right next step depends on the facts, dates and documents.
Is WPI the same as being unable to work?
No. WPI is a medical impairment measure. Work capacity, weekly payments, damages, treatment disputes and TPD issues are separate questions, although the evidence may overlap.
Does pain alone create a WPI percentage?
Not by itself. NSW workers compensation excludes AMA5 Chapter 18 on pain. Chronic pain is assessed through the underlying diagnosed condition where the Guidelines permit it.
Can secondary psychological symptoms be added to physical WPI?
In NSW workers compensation, secondary psychiatric or psychological impairment is not assessed as permanent impairment. Primary psychological impairment is assessed separately and is not combined with physical WPI.
Injury pathway enquiry
Not sure which claim type matches the injury?
Start with how the injury happened, what medical records exist and how work or daily activity has changed. The same injury can sit in different pathways.