Notice the blue overlay on the Accuro display image; this indicates the spinous process cross-section is detected. When scanning a particular intervertebral level, if no orange interlaminar-space overlay appears, the interlaminar space will not be easily accessible with a midline approach.
Consider the following Accuro overlay indications:
In the above instances, identification of the interlaminar space may be attempted again after repositioning the patient or moving to a different intervertebral level.
Alternatively, a paramedian approach may be attempted using the thoracic presetting, which identiﬁes a prescribed paramedian needle path based on the Accuro Locator needle guide.
Reasons for an obstructed view.
Ligament calcifications appear as bone under the ultrasound, consequently obstructing the interlaminar view. Inaccessibility to the interlaminar space can be caused by spinal stenosis, osseous growths, or calcifications of surrounding ligaments. It occurs most often in the elderly population.
Accuro can be used to identify the spinous process position as a means to guide a paramedian lumbar epidural technique* as shown.
*Paramedian lumbar epidural protocol details from Ghosh et al., BJA Education, 16(7): 213-220 (2016)