What does the muscle biopsy test involve?

The muscle biopsy involves taking samples of muscle from the lower part of your thigh. The biopsy is a surgical procedure through an incision (cut) in the skin that is usually 5 – 7 cm long. This procedure is performed in an operating theatre and usually takes no more than 45 minutes to 1 hour.

When will I get the results of the biopsy?

You will have your results on the same day as the biopsy and you will receive a written report.

How long will I be in hospital for?

If you are travelling home on your own by public transport then you will be discharged on the morning of the day after the biopsy. Patients cannot drive themselves home under any circumstances. If someone is with you, then generally you can leave on the day of the biopsy after you have seen the anaesthetist.

Will I have pain following the biopsy?

The local anaesthetic will last for around 6 hours, meaning there will be weakness and numbness of the leg for this period. As this begins to wear off you will start to experience some pain or discomfort at the site of the muscle biopsy. Pain killers will be prescribed to help ease this and patients will be advised of further pain medication on discharge. The pain is similar to that of a torn muscle and is usually manageable with routine painkillers.

How long will this last?

This varies between patients. Based on our surveys in the past, patients experience pain for an average of 6 days (ranging from 0 to 60 days) and use painkillers for an average of 3 days.

How big will the scar be?

The scar is normally around 5 – 7 cm and is located just above the knee. In a survey, 96% of the patients described their scar as either hardly noticeable or acceptable. The scar was described as poor in about 4% of the patients.

Are there any complications of the muscle biopsy?

We have surveyed patients 6 months after their muscle biopsy. Approximately 50% of patients reported some numbness around the scar and knee initially. This resolved subsequently in half of them. No patient has reported persistent pain or soreness around the scar. Most patients say they have had to limit normal physical activities for about 10 days after the surgery. It usually takes an average of 1 week after the biopsy before patients feel able to drive safely. This is when the patient has no discomfort or muscle weakness which would stop them from reacting quickly in an emergency. The average period of absence from work after the biopsy was one week. Other uncommon problems patients reported were “knee twitches”; itchiness around the scar; difficulty in bending the knee and climbing stairs.

What is recommended in terms of work/exercise after the muscle biopsy?

Returning to work depends on the type of work and the individual themselves. A more physical job may require a longer period off work, however, generally no more than a week off would be required. In terms of exercise we would recommend that you gradually return to your normal activities. Depending on the type and intensity of exercise you wish to do, it can take between 2 and 6 weeks to get back to normal.

How long should I avoid driving?

There is no set limit, however, patients cannot drive home following their biopsy and we advise they do not drive until they have the strength to comfortably perform an emergency stop. For most patients this usually takes a week.