What are spondylolysis and spondylitis?

Spondylolysis and Spondylitis: Distinct Spinal Conditions

Spondylolysis is a stress fracture or defect in the pars interarticularis of the vertebra (the bony bridge connecting upper and lower facet joints), while spondylitis refers to inflammatory arthritis affecting the spine and sacroiliac joints.

Spondylolysis

Definition and Pathophysiology

• Spondylolysis represents a weakness or stress fracture in the pars interarticularis, the bony bridge connecting the upper with the lower facet joints of the vertebra 1.
• The lesion likely represents a stress fracture caused by cumulative repetitive stress imposed by physical activity, particularly in sports requiring repetitive spinal hyperextension 2.
• The pars defect typically occurs in early childhood and results from a growth disturbance of the lumbosacral vertebrae linked to bipedal standing position, depending on genetic and environmental factors 3.

Clinical Presentation

• Spondylolysis is the most common cause of low back pain in young athletes, accounting for one-half of all pediatric and adolescent back pain in athletic patients 1.
• The hallmark symptom is low back pain aggravated by activity, frequently accompanied by minimal or no physical findings 1.
• Athletes involved in sports requiring repetitive hyperextension (diving, weightlifting, gymnastics, wrestling) are at highest risk 4.
• Most cases are asymptomatic, but symptomatic cases can be very disabling 3.

Diagnostic Approach

• Plain radiography with posteroanterior, lateral, and oblique views is useful for initial diagnostics, with a sensitivity of 77.6% for anterior-posterior and lateral radiographs 5.
• MRI is especially useful for detecting active spondylolysis and can show edema in the region of the pars interarticularis or adjacent pedicle, even when radiographs are negative 5.
• MRI findings are positively associated with clinical symptomatology, and resolution of signal abnormalities suggests response to therapy 5.
• CT has high sensitivity for evaluating spondylolysis and is superior to radiographs 5.
• Technetium-99m bone scan with SPECT is a sensitive screening tool and can demonstrate increased uptake due to stress reaction when CT reveals no abnormality 5.

Management

• Conservative treatment is usually successful, requiring activity restriction (temporary discontinuation of the aggravating sport or activity) and may require bracing 2.
• Most patients do not require surgery 3.
• Surgical treatment is indicated only for symptomatic cases when conservative methods fail 1.
• Referral to a spine surgeon is recommended for any patient suspected of having spondylolysis due to risk of disease progression 4.

Spondylitis (Ankylosing Spondylitis)

Definition and Pathophysiology

• Ankylosing spondylitis is a form of chronic inflammatory arthritis characterized by sacroiliitis, enthesitis, and a marked propensity for sacroiliac joint and spinal fusion 5.
• AS is part of the spondyloarthritis family of diseases, distinguished by universal involvement with sacroiliac joint inflammation or fusion and more prevalent spinal ankylosis 5.
• The term axial spondyloarthritis encompasses both radiographic AS and nonradiographic axial spondyloarthritis 5.

Clinical Presentation

• The main symptom is chronic low back pain with inflammatory characteristics: morning stiffness predominating in the second half of the night that improves with exercise 5.
• Other musculoskeletal manifestations include arthritis, enthesitis, and dactylitis 5.
• Extra-musculoskeletal manifestations include uveitis, psoriasis, and inflammatory bowel disease 5.
• Patients experience substantial deterioration in health-related quality of life due to impaired function, work productivity, and social interactions 5.

Treatment Goals

• The goals are to reduce symptoms, maintain spinal flexibility and normal posture, reduce functional limitations, maintain work ability, and decrease disease complications 5.

Management Algorithm

First-line treatment:

• NSAIDs are strongly recommended as first-line therapy for patients with active AS 5.
• Physical therapy is strongly recommended 5.

Second-line treatment:

• Tumor necrosis factor inhibitors (TNFi) are strongly recommended when activity persists despite NSAID treatment 5.
• No particular TNFi is preferred except in patients with concomitant inflammatory bowel disease or recurrent iritis, in whom TNFi monoclonal antibodies should be used 5.

What NOT to use:

• Systemic glucocorticoids are strongly recommended against in AS 5.

Advanced disease:

• Hip arthroplasty is strongly recommended for patients with advanced hip arthritis 5.

Important Caveats

• Radiographic features may take years to develop, potentially excluding patients early in the disease course 5.
• The mainstays of treatment have been NSAIDs and exercise, with additional use of slow-acting antirheumatic drugs in patients with peripheral arthritis 5.
• Early identification and adequate treatment are priorities in achieving treatment goals 5.