What Factors Are Relevant to Whether Treatment is Reasonable & Necessary?

In Brief

• Treatment relates to the injuries sustained in the accident if the accident made a material contribution, at least, to the need for treatment.
• Relevant, but not determinative, factors relevant to whether treatment is reasonable and necessary include whether the treatment is appropriate, whether the treatment is likely to be effective, the availability of alternative treatment, the cost-effectiveness of the treatment and whether the treatment is supported by medical experts.

Facts

The Personal Injury Commission (PIC) published its decision in Allianz Australia Insurance Limited v Mataraci [2025] NSWPICMP 536 on 8 August 2025.

The Claimant was injured in a motor accident on 12 February 2022 when the Insured failed to stop at a stop sign.

The Claimant subsequently requested that the Insurer approve a posterior L5/S1 decompression and fusion surgery. A Medical Assessor determined that the surgery was related to the motor accident and was reasonable and necessary.

The Insurer successfully obtained a review of the original Medical Assessor’s decision.

The Review Panel’s Decision

The Review Panel determined that the proposed surgery was related to the injuries sustained in the motor accident for the following reasons:

• The accident did not need to be the sole cause of the need for the Claimant’s surgery. To establish causation, the Review Panel need only be satisfied that the accident made a material contribution to the need for the proposed surgery: AAI Limited t/as AAMI v Phillips [2018] NSWSC 1710.
• After reviewing all the medical evidence, the Review Panel accepted that the motor accident made a material contribution, at least, to the need for surgery.
• The Claimant’s independent condition of multiple sclerosis would not have led to the need for surgery.
• But for the motor accident, and on the balance of probabilities, the surgery would not have been required.

The Review Panel also agreed that the proposed surgery was reasonable and necessary for the following reasons:

1. The test under s 3.24(2) of the Motor Accident Injuries Act 2017, that the treatment be “reasonable and necessary“, is stricter than the “reasonably necessary” test used in the workers compensation arena, because the word “necessary” is not qualified. Treatment is either necessary or it is not.

2. Factors relevant to – but not determinative of – whether treatment is reasonable and necessary include:

• Whether the treatment is appropriate.
• Whether alternative treatment is available.
• Whether the treatment is cost-effective.
• Whether the treatment is actually, or potentially, effective.
• Whether medical experts support the proposed treatment.

3. In this case the proposed surgery was reasonable and necessary because:

• The surgery was clinically indicated in circumstances where non-operative treatment had not resulted in ongoing resolution of the Claimant’s lower back pain, right buttock pain and L5 radiculopathy.
• Decompressing a symptomatic lumbar nerve root is appropriate given that the Claimant had already tried alternative treatment to decompress the nerve via peri-neural steroid injections and chiropractic treatment.
• The likely cost of the surgery was unlikely to exceed the cost of extensive conservative care.
• The decompressive surgery was likely to be effective.

Why This Case is Important

The Review Panel’s decision in Mataraci provides a useful example of a decision maker working through the factors relevant to whether proposed treatment is reasonable and necessary and related to the injuries sustained in the accident.

If you would like to discuss this case note, please don’t hesitate to get in touch with CTP Practice Group Leader Peter Hunt today.

Additional McCabes Resources

• MC PIC Decision of the Week
• MC MAIA Toolkit
• The Proper Lookout Podcast
• MC Ready Reckoner