Pressure Injury Classification and Documentation

Staging Classification

Full-thickness sacral ulcers should be classified as Stage III or Stage IV pressure injuries, depending on whether bone, tendon, muscle, or ligament is exposed, according to the Clinical Infectious Diseases guideline 1
The current staging system distinguishes full-thickness ulcers based on the deepest tissue layer involved, with Stage III characterized by full-thickness tissue loss exposing subcutaneous fat, and bone, muscle, and tendon not visible or directly palpable 1
Stage IV pressure injury is characterized by full-thickness tissue loss with exposed bone, muscle, ligament, or tendon, and may involve undermining, tunneling, and osteomyelitis when bone is exposed and infected 1

The sacral region should be specified as the anatomic site when documenting sacral pressure injuries, with the sacrum being the most common location for pressure ulcers (39% of all pressure injuries) 1, 2
Sacral ulcers have lower recurrence rates after surgical repair compared to ischial or trochanteric ulcers, according to the Annals of Internal Medicine guideline 3

Complete documentation should include the stage (III or IV based on deepest tissue involvement), wound dimensions, amount and type of necrotic tissue, exudate characteristics, and surrounding skin condition, as recommended by the Praxis Medical Insights guideline 4, 2

The Clinical Infectious Diseases guideline recommends not staging a wound covered by eschar or slough, as these must be classified as "unstageable" until debrided 1
The preferred term is "pressure injury" or "pressure ulcer", rather than outdated terminology such as "decubitus ulcer" or "bedsore", according to the Clinical Infectious Diseases and Praxis Medical Insights guidelines 1, 4

The lower sacral segments (below S3/S4) have subcutaneous bone with poor intrinsic blood supply, predisposing to deep tissue injury 5
Patients with sacral pressure injuries typically present with limited mobility or immobilization 6

When bone is exposed or palpable in a Stage IV sacral pressure injury, pelvic osteomyelitis (POM) must be suspected, and the lower sacral segments are particularly vulnerable because the bone is subcutaneous with poor blood supply 5, 7
MRI without and with IV contrast is the preferred initial imaging for suspected bone involvement, with a sensitivity of 96% and specificity of 94% for spine infection 6
CT with IV contrast can evaluate osseous detail and paraspinal soft tissue abnormalities, with a sensitivity of 79% and specificity of 100% 7