What is SRS and how do we treat it?
The rib cage consists of twenty-four ribs, costal cartilage, joints, breast bone (sternum) and the mid (thoracic) spine.
All ribs are attached to the mid-portion of the spine by joints. Each rib also has a nerve, artery, and vein that run underneath it. The first seven ribs are connected to the sternum by costal cartilages. Ribs 8 to 10 are not directly attached to the sternum but instead to the costal cartilage of the 7th rib. They are therefore often referred to as ‘false ribs.’ Ribs 11 and 12 are often referred to as ‘floating ribs’ and are only attached to the spine.
Costal cartilages are the connective tissue at the front (anterior) end of the ribs connecting them to the sternum. This cartilage functions as a cushion between the sternum and ribs allowing the chest to expand when you breathe.
The rib cage serves several purposes. Firstly, to protect vital organs such as the heart and lungs that sit within them and to support the thoracic portion of your spine. It is also is critical in facilitating chest movement for breathing.
Slipping Rib Syndrome (SRS) is a rare condition where the costal cartilage on a person’s lower ribs slips or dislocates from the rest of the rib cage. This leads to movement of the effected rib which can compress the nerve running under the rib above. This can cause pain in the chest or upper abdomen. It typically affects the 8th, 9th, or 10th ribs, which are more flexible and are not directly attached to the sternum.
There are other variants of this condition that can effect ribs 11 and/or 12. These are sometimes referred to as Floating Rib Syndrome and/or 12th Rib Syndrome. Patients can sometimes have both SRS and Floating Rib Syndrome.
Symptoms
For many patients the exact cause of SRS is unknown. Contributing factors may include trauma (such as car accidents or sports injuries), hypermobility of the joints between the ribs and the spine, or intense physical strain such as heavy lifting.
As noted above, SRS typically affects the 8th, 9th, or 10th ribs (‘false ribs’) because these ribs aren’t connected directly to the sternum and hence are more susceptible to dislocating.
Diagnosing SRS and other variants of this condition is challenging because it is rare, symptoms differ from patient to patient, and other conditions may cause similar symptoms.
Patients are often seen by multiple healthcare providers such as physiotherapists, chiropractors, GPs, and orthopaedic surgeons before getting a diagnosis.
It is often a diagnosis of exclusion. This means other conditions that could be causing symptoms (costochondritis, fractures, or Tietze syndrome) are ruled out first using imaging such as Computerised Tomography (CT) scans or Magnetic Resonance Imaging (MRIs).
SRS is often confirmed by physical examination which includes the hooking manoeuvre. This is when a trained healthcare provider hooks their fingers under the lower ribs and pulls them forward (subluxes) which reproduces the pain.
Dynamic ultrasound may show motion of the cartilage of the lower ribs slipping under the ribs above them particularly during manoeuvring such as abdominal crunches. This test often confirms the diagnosis.
For many patients the exact cause of SRS is unknown. Contributing factors may include trauma (such as car accidents or sports injuries), hypermobility of the joints between the ribs and the spine, or intense physical strain such as heavy lifting.
As noted above, SRS typically affects the 8th, 9th, or 10th ribs (‘false ribs’) because these ribs aren’t connected directly to the sternum and hence are more susceptible to dislocating.
SRS does not often result in any long-term damage and in some cases, symptoms resolve.
Initial conservative treatment often includes avoiding strenuous activity, exercise therapy, a single nerve root injection, and medications such as anti-inflammatories prescribed by your doctor. If symptoms persist surgical treatment can be considered.
Traditionally, surgery for this condition involved removing the effected rib to prevent it from slipping and irritating the surrounding nerves. This surgical technique, however, has been associated with limited success in improving pain. Patients often still experience pain because the rib is still attached to the spine at the joint and there is still movement of the rib and irritation of the nerve at this location.
A newer surgical technique performed by Mr Alam is called a chest wall stabilisation procedure, as first described by Dr Adam Hansen. The goal here is to minimise movement of the effected ribs in relation to the rest of the rib cage, thereby minimising irritation of surrounding nerves and alleviating the pain.
During surgery, two manoeuvres are performed to stabilise the ribs. The first involves placing a piece of cartilage (graft) as a spacer between the effected ribs (see image 04 above). The second step involves using a fibre tape above and between the effected ribs to secure them in place. These two techniques prevent the ribs from both moving too far apart, and too close together.
This is the standard operation, performed by Mr Alam however, each surgery is tailored to the specifics of the patient’s anatomy.