How do you assess for saddle anesthesia?

From the Guidelines

To assess for saddle anesthesia, a focused sensory examination of the perineal region, including light touch and pinprick sensation tests, as well as assessments of anal tone and the bulbocavernosus reflex, should be performed. This approach is crucial for early detection of potential neurological complications, such as cauda equina syndrome, which can arise from epidural anesthesia 1. The assessment should include explaining the procedure to the patient, ensuring privacy, and using appropriate tools like a cotton swab or safety pin to test sensation in the perianal area, buttocks, genitals, posterior thighs, and medial thighs. The patient should be asked to report any sensation and compare it to normal areas of skin.

Key components of the assessment include:

• Testing light touch and pinprick sensation in the perianal area, buttocks, genitals, posterior thighs, and medial thighs.
• Evaluating anal tone by checking for voluntary contraction of the anal sphincter.
• Assessing the bulbocavernosus reflex by squeezing the glans penis or clitoris and observing for anal contraction. These steps are essential for identifying decreased or absent sensation characteristic of saddle anesthesia, which, when accompanied by other symptoms like bowel or bladder dysfunction, may indicate sacral nerve root compression 1. Prompt identification and management of such conditions are critical to prevent permanent neurological damage.

In the context of epidural analgesia during labor, as discussed in the safety guideline by the Association of Anaesthetists and the Obstetric Anaesthetists' Association 1, monitoring for sensory and motor block is recommended, with an emphasis on assessing leg strength as a critical monitor of spinal cord health. However, the specific assessment for saddle anesthesia involves a detailed sensory examination of the perineal region, which is vital for detecting early signs of neurological compromise.

From the Research

Assessment of Saddle Anesthesia

To assess for saddle anesthesia, several key points must be considered:

• Saddle anesthesia is a symptom that can be associated with cauda equina syndrome, a condition that requires urgent diagnosis and treatment 2, 3.
• The assessment of saddle anesthesia involves evaluating the patient's symptoms, including numbness or tingling in the saddle area, as well as other potential symptoms such as bowel and bladder dysfunction, and sexual dysfunction 2, 4.
• A thorough neurologic examination is essential in assessing patients with suspected saddle anesthesia, including evaluation of the brainstem and spinal cord function 5.
• Imaging studies, such as MRI, may be necessary to confirm the diagnosis and identify the underlying cause of the saddle anesthesia 2, 4.

Key Findings

Some key findings that may indicate saddle anesthesia include:

• Numbness or tingling in the saddle area, which can include the perineum, genital area, and anus 2, 4.
• Bowel and bladder dysfunction, such as constipation, urinary retention, or incontinence 2, 3.
• Sexual dysfunction, such as impotence or decreased libido 2, 4.
• Weakness or paralysis of the lower extremities 3.

Diagnostic Approach

The diagnostic approach to saddle anesthesia involves:

• A thorough medical history and physical examination, including a neurologic examination 2, 3.
• Imaging studies, such as MRI, to confirm the diagnosis and identify the underlying cause of the saddle anesthesia 2, 4.
• Laboratory tests, such as urine analysis and blood work, to rule out other potential causes of the symptoms 3.
• Consultation with a specialist, such as a neurosurgeon or orthopedic surgeon, if cauda equina syndrome is suspected 2, 3.