Lumbar Stress Fracture (Spondylolysis) in Teenagers
and Competitive Swimmers
A lumbar stress fracture or ‘Spondylolysis’ is a non-displaced fracture of a part of the lumbar vertebrae called the pars interarticularis.
Spondylolysis is a common and costly cause of back pain in competitive swimmers as well as a range of other adolescent sports people (e.g. gymnasts, divers).
Spondylolysis most commonly occurs at the L5 vertebrae (90-95%), and is caused by repeated or excessive trunk extension (backward arching), which places stress on this area of the vertebrae.
The stress fracture can occur on either the right or left side of the vertebrae, and in some cases, both sides!
Most Spondylolysis heal with conservative management. Around 25% suffer non-union. In these cases, the fracture becomes thickened with fibrous connective tissue rather than bone.
Spondylolysis can be classified based on its causative mechanism:
· Dysplasic/Congenital (born with it)
· Isthmic (sport related, due to repetitive/excessive extension stress)
· Degenerative (related to ageing and degeneration)
· Traumatic (result of an acute hyperextension injury)
About 50% of Spondylolysis progress to a Spondylolisthesis (a slip forward of one vertebrae on another).
This is more common in those with a bilateral Spondylolysis (i.e. a stress fracture on both the right and left side of the vertebrae).
Spondylolisthesis are graded on a scale of I-IV based on how far the top vertebrae has slipped forward on the bottom vertebrae. Grade I and II are usually conservatively managed, while GIII and IV may require stabilization surgery.
Diagnosis of spondylolysis is made through an assessment of subjective pain history and physical examination by a Physiotherapist or Sports Physician, as well as radiological investigation to identify the fracture line. XRAY may be able to identify the fracture in some cases, although SPECT bone scan and CT scan are more sensitive. MRI is not as sensitive, but might be prescribed as an alternative to bone scan and CT in adolescents, to avoid exposure of the immature skeleton to radiation.
With regard to competitive swimming, Butterfly and Breaststroke swimmers are most at risk, due to the repetitive lumbar extension movement that occurs during these strokes, particularly on the breathing stroke:
A key technique factor is related to minimizing the amount of vertical (up/down) movement throughout the stroke, particularly on the breathing strokes. Not only does this reduce drag and improve efficiency, it also reduces lumbar extension stress:
Image: Butterfly breathing high breath position vs. low breath position
Swimming is a total body exercise, so achieving a good body position, and avoiding excessive lumbar extension in swimming, requires adequate mobility and postural strength throughout the entire body-line:
Tight shoulders can result in excessive lumbar extension in the swimmers effort to achieve a streamline position:
Similarly, tight hip flexors can result in increased lumbar extension in a swimming position. Thirdly, weak trunk musculature can cause the abdomen to ‘sag’ in the water, resulting in increased lumbar extension:
It is important to maintain balanced mobility throughout the thoracolumbar and lumbopelvic spine and hip in order to distribute extension load throughout the kinetic chain. “Hinging” at one spinal segment can focus stress on one vertebral level:
· Lumbar spine bony abnormalities (e.g. pseudoarthrosis or sacralised L5)
· Male gender (2:1)
· Early childhood (learning to stand and walk)
· Adolescence (highly active people playing sport with skeletal immaturity)
· Tight hip flexor and/or hamstrings muscles
· Weak trunk and gluteal musculature
· Poor postures and gait patterns (hyperlordotic postures)
Conservative management of spondylolysis is successful in 85% of adolescents that present with an acute case, however, there is a high potential for recurrence if the aforementioned risk factors are not addressed.
Conservative management pathways vary on a case by case basis, but generally consist of:
· Relative rest from aggravating activities for 6-12 weeks to allow bony healing
· A Physiotherapy guided core strengthening, neuromuscular control and range of motion and flexibility exercise program. Pilates is often useful during this rehabilitation.
· Symptom free stationary cycling for aerobic maintenance
· Pain management through Physiotherapy and the use of pharmacological analgesia, which may include non-steroidal anti-inflammatories
· Progressive, symptom limited return to sport including analysis and correction of sport specific technique errors related to lumbar extension stress
Some Physiotherapists or Sports Physicians may also recommend using a semi-rigid trunk brace during the rest and rehabilitation period in order to help control pain symptoms. These are prescribed on a case-by-case basis and are not always necessary.
Spondylolysis is the most common cause of low back pain in adolescent athletes.
If you have low back pain, visit RHP Physiotherapy for an assessment and up to date, evidence based treatment. Call us on 07 3856 5566 for an appointment