What is the best diagnostic test to evaluate tunneling and an old wound on a buttock?

From the Guidelines

The best diagnostic test to evaluate tunneling and an old wound on a buttock is a wound assessment with probe measurement, combined with imaging studies such as MRI or ultrasound. For initial evaluation, a sterile probe should be gently inserted into the wound to determine the depth and direction of tunneling, measuring in centimeters. This provides immediate information about the extent of undermining. For more detailed assessment, MRI is preferred as it can visualize deep tissue involvement, potential abscesses, and the relationship to surrounding structures like the sacrum or ischium 1. Ultrasound offers a less expensive alternative that can still identify fluid collections and assess tissue integrity. CT scanning may be useful if osteomyelitis is suspected, as it can depict cortical bone well and play a role in the diagnosis of chronic osteomyelitis 1. These imaging studies are crucial because tunneling wounds on the buttock may be associated with pressure injuries, pilonidal disease, or perianal abscesses, and proper diagnosis affects treatment planning.

Some key points to consider in the evaluation of tunneling wounds include:

• The use of assessment tools such as NERDS/STONES or the International Wound Infection Institute–Wound Infection Continuum (IWII–WIC) to increase diagnostic specificity 1
• The importance of evaluating wound bed characteristics, exudate, surrounding tissue condition, and potential for infection to guide appropriate wound care interventions
• The role of imaging techniques such as ultrasound, MRI, or CT in determining the extent of soft tissue infection and the presence of underlying abscesses that would require drainage 1

Overall, a comprehensive approach that combines wound assessment with probe measurement and imaging studies is necessary for accurate diagnosis and effective treatment of tunneling wounds on the buttock.

From the Research

Diagnostic Tests for Tunneling and Old Wound on a Buttock

To evaluate tunneling and an old wound on a buttock, several diagnostic tests can be considered. The choice of test depends on the clinical presentation and the suspected underlying condition.

• Magnetic Resonance Imaging (MRI): MRI is a highly sensitive and specific imaging modality for detecting osteomyelitis and soft tissue abnormalities 2, 3, 4, 5. It provides detailed images of the anatomy and can help identify the extent of the infectious process.
• Computed Tomography (CT) Scan: CT scan can be useful in detecting early osseous erosion and documenting the presence of sequestrum, foreign body, or gas formation 2, 6. However, it is generally less sensitive than MRI for detecting bone infection.
• Ultrasound: Ultrasound can be useful in detecting fluid collections and guiding diagnostic or therapeutic aspiration, drainage, or tissue biopsy 2. However, it may underestimate the extent of the disease.
• Plain Radiography: Plain radiography can provide an overview of the anatomy and pathologic conditions of the bone and soft tissues 2. However, it may not be sensitive enough to detect early changes in osteomyelitis.

Considerations for Diagnostic Testing

When choosing a diagnostic test, consider the following factors:

• Clinical presentation: The presence of symptoms such as pain, swelling, and redness can guide the choice of diagnostic test.
• Suspected underlying condition: The suspected underlying condition, such as osteomyelitis or soft tissue infection, can influence the choice of diagnostic test.
• Availability of imaging modalities: The availability of imaging modalities, such as MRI or CT scan, can impact the choice of diagnostic test.

Summary of Diagnostic Tests

In summary, MRI is a highly sensitive and specific imaging modality for detecting osteomyelitis and soft tissue abnormalities. CT scan and ultrasound can be useful in certain situations, but may have limitations. Plain radiography can provide an overview of the anatomy, but may not be sensitive enough to detect early changes in osteomyelitis. The choice of diagnostic test depends on the clinical presentation and suspected underlying condition 2, 6, 3, 4, 5.