Sports Medicine
Sports Injury Prevention & Rehabilitation

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(Also known as Pars Defect, Lumbar Spine Stress Fracture, Stress Fracture of the Pars Interarticularis)
What is a spondylolysis?
A spondylolysis is the name given to a stress fracture of the lumbar spine (lower back) and specifically affects a region of bone known as the pars interarticularis.
The spine comprises of many bones known as vertebrae. Each vertebra connects with the vertebra above and below via two types of joints: the facet joints on either side of the spine and the disc centrally. These joints are designed to support body weight and enable spinal movement.
During certain movements of the spine, compressive force is placed on the facet joint. This force is then transmitted through a bony region known as the 'pars interarticularis'. If these forces are excessive and beyond what the bone can withstand, bony damage will occur. This initially results in a bony stress reaction, however, with continued damage may progress to a bony fracture of the pars interarticularis. This condition is known as a spondylolysis.
A spondylolysis typically occurs on one side of the spine, however, occasionally both sides may be involved. This can result in one vertebra slipping forwards on another and is known as a spondylolisthesis.

Causes of a spondylolysis
A spondylolysis usually occurs as a result of repeated or forceful hyperextension activities, especially when they are combined with rotation. They are typically overuse injuries and are more common in the younger athlete whose bones are yet to reach skeletal maturity.
A spondylolysis is most commonly seen in the following sports:
  • figure skating
  • gymnastics
  • tennis
  • dance
  • weight lifting
  • wrestling
  • pole vaulting
  • high jump
  • throwing sports (javelin, baseball pitching etc.)

Signs and symptoms of a spondylolysis
Patients with this condition typically experience pain on one side of the lower back that progressively increases with movements involving hyperextension. Symptoms generally decrease with rest. Pain in the lower back is usually felt on the opposite side of the body to the arm performing the repetitive movement (e.g. left sided back pain for a right arm bowler etc). Pain can usually be reproduced by firmly pressing on the affected area, or, by extending backwards while standing on the affected leg, with the aid of a therapist.

Diagnosis of a spondylolysis

A thorough subjective and objective examination from a physician may be sufficient to diagnose a spondylolysis. X-rays may or may not demonstrate a stress fracture, depending on the severity of injury. Usually a bone scan is used to confirm an area of bony damage. Following this, a CT scan may be used to determine the presence of a stress fracture. Occasionally, other investigations such as an MRI may be indicated.

Treatment for a spondylolysis
Treatment for patients with this condition involves an initial period of rest from the aggravating activity (this may involve the use of a back brace). Once the patient is pain-free, a gradual increase in activity and exercise can occur, provided symptoms do not increase. Alternative exercises placing minimal force through the affected bones should be performed to maintain fitness such as swimming, cycling and water running, provided they are pain-free. Stretches for the back, hips, gluteal and hamstring muscles, as well as exercises to strengthen and improve core stability, should also be performed with direction from the treating physical therapist.

Prognosis of a spondylolysis
Rehabilitation following a spondylolysis usually occurs over weeks to months with direction from a physiotherapist and will vary depending on the severity of injury. With appropriate treatment, most minor stress fractures should be able to achieve bony union in 6 to12 weeks. Once this is achieved and the patient is symptom free, a gradual and progressive return to activity is indicated under guidance from a physical therapist. This usually occurs over a period of approximately 4 to 6 weeks. More severe fractures may require an extended period of rehabilitation.
In some cases, a stress fracture may result in non-union of the bone and on-going problems (especially if they are managed inappropriately). Accurate diagnosis, treatment and management in the early stage is therefore vital.

Physical therapy for a spondylolysis
Physical therapy for patients with this condition can hasten the healing process, reduce the likelihood of future recurrence and ensure a safe return to activity. Treatment may comprise:
  • soft tissue massage
  • electrotherapy (e.g. ultrasound)
  • mobilization
  • dry needling
  • education
  • activity modification advice
  • the use of a back brace
  • biomechanical correction
  • clinical Pilates
  • hydrotherapy
  • exercises to improve flexibility, strength, posture and core stability
  • a gradual return to activity program
  • Technique adjustment should also be made to restrict the amount of extension during sporting activity. This may be assisted by the use of a back brace.

Contributing factors to the development of a spondylolysis
There are several factors that may contribute to the development of this condition. These need to be assessed and corrected with direction from a physical therapist and may include:
  • poor sporting technique
  • inappropriate training volumes
  • inappropriate sporting surfaces
  • poor posture
  • lumbar spine stiffness
  • a lack of core stability
  • muscle weakness or tightness
  • poor foot biomechanics

Other intervention for a spondylolysis
Despite appropriate physical therapy management, a small percentage of patients with this condition fail to improve adequately and may require other intervention. This may include pharmaceutical intervention, corticosteroid injection, further investigations such as X-rays, CT scan, MRI or bone scan or assessment from an orthopaedic specialist who can advise on any procedures that may be appropriate for the condition. The treating physical therapist can advise if this is required and will refer to the appropriate medical authority if it is warranted clinically.