Because SMA causes muscles to get weaker, people with SMA can have problems with the bones that are supported by the muscles (orthopaedic problems). SMA can weaken the muscles that support the spine which, without this support, can be pulled by gravity and curve. It’s estimated that as they grow, 60-90% of people who have SMA and are either unable to sit or able to sit but unable to stand and walk develop a spinal curvature, as do 50% of people who can walk. When the spine curves sideways into a “C” or “S” shape it’s called a scoliosis. When the spine bends forward it’s called a kyphosis. At the same time as the spine curves, there are changes to the chest wall and rib cage which reduce the space available for the lungs to grow and for breathing.

Weakening muscles can also mean that some people who are sitters and walkers have ‘unstable hips’. How much muscles weaken and what effect this has on anyone’s spine and hips day to day is very individual – no two people are the same.

Another thing that can be an issue for many who have SMA is not being able to use bones and muscles as much as someone who can walk. This makes you more at risk of bone fractures due to osteoporosis (when bones are weaker and more likely to break).  If you can, standing can help with this as well as being good for many things including your breathing, blood circulation, bladder, bowels and joints. Your physio and OT can tell you more about how and why (see also Posture, Movement and Exercise on this page).

Regular check ups

Whichever Type of SMA you have, you should be having regular assessments and reviews by people such as an orthopaedic consultant, physio or occupational therapist (OT). The main reason for these check-ups is that being seen regularly means that any issues you’re having can be managed in a way that will help you with achieving or maintaining your movement and well-being. If you’re having difficulties with your spine or hips you can then be seen more often.

At these check ups, whoever you see will be checking to see if your spine is curving. This is best done by an X-ray of the whole spine, so the curve can be measured. If you can sit or walk, the X-ray is taken with you in the most upright sitting or standing position you can manage. Otherwise, your X-ray will be done while you’re lying flat. The measurement used is called the Cobb angle and it’s measured in degrees.

At your appointments, you should have plenty of time to talk with your medical team so that you know exactly what they’re measuring and why, as well as what’s involved with any options they might suggest to help you. Hopefully, you’ll feel comfortable about asking them questions about anything you don’t understand, that you’re finding difficult or you’re worried about. If not, tell your parents and they’ll ask for you.

Checking your diet gives you what you need for your bones

To help prevent osteoporosis, it’s really important you have enough calcium and vitamin D3 in your diet. If you aren’t sure if you’re getting enough, talk to your parents and / or medical team. You may get to see a dietitian who can give advice.

If your scoliosis is over 20 degrees (as measured by the Cobb angle) you may already have been given a spinal brace or body jacket, sometimes called a TLSO (thoraco-lumbar sacral orthosis). This is to help keep you well supported so that you’re in an upright sitting position and you are relived of any pain you may have.

Spinal braces can be made of different materials: some are flexible, some are more rigid. Whichever is recommended, they have to be made to measure just for you. Measurement and fitting is done by a specialist called an orthotist. You may want to talk to your orthotist about the kind of clothes you like to wear so that they can try to take this into account. They’ll also tell you when you need to wear your brace.

Unfortunately, though a spinal brace or body jacket may slow down the curving of your spine, wearing one can’t stop it happening, so there may come a point when your medical team says it would be a good idea to have spinal surgery. Many who are non-sitters or sitters have had this by the time they are teenagers.

Spinal surgery is usually recommended when the spinal curve Cobb angle has progressed to 50 degrees or more and when the curve is increasing by 10 degrees or more each year. It’s done to help with posture and balance when sitting. Being able to be straight also means that  the lungs can expand more fully, which helps with breathing.

If spinal surgery is a possibility for you, your medical team will also think about:

• How old you are in years and months (your chronological age) and whether your bones and skeleton are fully grown (skeletal maturity). Since skeletal age and actual age often don’t match in SMA, they can estimate your skeletal maturity by taking an X-ray of the bones in your left wrist!
• Whether you’re having more difficulty with breathing and your curve has increased
• If your chest wall shape has changed
• If your curve is causing problems day-to-day at home and school and when you’re out and about
• If you’re having a lot of back and hip pain
• If your hips and pelvis are getting uneven, making it difficult for you to sit or lie down.

There are two types of spinal surgery:

• ‘Growth-friendly’ spinal surgery. This is recommended for children who still have a lot of spine and rib cage growing to do, so usually it’s for children less than 10 years old. If you had spinal surgery before you were 10 years old, this is likely to have been what you had. The spinal rods are only attached to the spine or ribs at the top and bottom of the curve, leaving the spine segments and ribs in-between untouched to allow for more growing. The spinal curve is straightened as much as possible when the rods are first placed, then every 2 to 6 months the rods supporting the spine are gradually lengthened.
• Spinal fusion. This involves straightening the spine by attaching two metal rods, one on each side of the spine, to many bones of the spine (vertebrae) and ribs along the spinal curve. This corrects the curve and supports the spine against gravity. The vertebrae are also fused together to provide additional support.

If anyone needs surgery beetween the ages of 4 and 10 years, the SoC recommend growth-friendly spinal surgery.

Anyone between the age of 10 and 12 years is still growing. This is called ‘transitioning to skeletal maturity’. If surgery is needed, the SoC say the type of surgery will depend on skeletal maturity and how much more the spine is likely to grow.

Anyone age over 12 years is usually skeletally mature. If surgery is needed, the SoC say it’s likely to be spinal fusion.

Whatever surgery people have now, it’s recommended that there should be an unfused area in the middle of the lower back (mid-lumbar) so that possible treatments, such as Spinraza®, that are injected via a needle directly into the spinal canal (intrathecally) can be given.

Before any operation, your medical team would be checking on your health and well-being. They would be looking at whether you have had any weight or dietary challenges, your bone health and whether you’re having difficulty with breathing. They would talk with you and your parents about exactly what’s involved and any risks and the benefits of having the surgery. Hopefully, you will feel comfortable about asking them questions about anything you don’t understand, are finding difficult or you’re worried about. If not tell your parents and they will ask for you.

Sometimes surgery is recommended for people who can sit or walk but are having a lot of pain or their hip problems are making day-to-day activities like eating, going to the toilet, dressing or sitting, difficult.

Again, if this is a possibility for you, your medical team should tell you all about any risks and benefits; you should have plenty of time to talk with them. Hopefully, you’ll feel comfortable about asking them questions about anything you don’t understand, are finding difficult or you’re worried about. If not tell your parents and they’ll ask for you.

Some people don’t mind hospitals and operations; other people hate them or can find them (or even just the thought of them) frightening. Lots of people are somewhere in the middle. For some people it helps to know exactly what’s going to happen and in great detail; others prefer just an outline (maybe how long the operation will take, where they’ll wake up, how long they’ll be there before they’re back at home, school or work).

Talk to your parents and medical team about what sort of things you want to know so that you can be prepared in the way that suits you best.