Post‑Procedure Monitoring and Safety for Diagnostic Peripheral Nerve Blocks

Motor Function Monitoring

Assess motor function at regular intervals (every 1–2 hours initially) until complete resolution to detect unexpected prolonged blockade that may indicate nerve injury or hematoma formation. 1
Perform a straight‑leg raise test; inability to complete the maneuver at 4 hours post‑block warrants immediate evaluation by the performing clinician. 1
Use the Bromage scale (scores 1–4, with 4 indicating full movement) for standardized documentation of motor block resolution. 1
Keep patients under observation or ensure they have assistance available throughout the period of motor blockade. 1

Record the expected dermatomal distribution of sensory blockade immediately after the block and track its resolution over time. 1
Inform patients that sensation typically returns within 4–12 hours for standard local anesthetics and up to 24 hours for long‑acting agents; advise them to report any delay beyond these windows. 1

If motor or sensory block persists longer than the pharmacologically expected duration (> 12 hours for standard agents, > 24 hours for long‑acting formulations), arrange urgent imaging (MRI or ultrasound) of the nerve distribution to exclude compressive hematoma or other structural complications. 1
Establish 24/7 escalation pathways that provide rapid access to urgent imaging and specialist consultation (neurology, neurosurgery). 1
Any worsening of motor weakness, expansion of the sensory deficit, or emergence of new symptoms (severe pain, paresthesias outside the blocked area) mandates immediate reassessment. 1
Progressive deficits rather than the expected gradual improvement should be interpreted as a possible complication. 1

Provide written discharge instructions that clearly outline the anticipated block duration, activity restrictions, warning signs, and a 24‑hour contact number for concerns. 1
Document a baseline neurological examination before the block and repeat the assessment before discharge to create a clear record of functional status. 1

Patients reporting persistent symptoms beyond the expected timeframe must be evaluated in person; telephone reassurance alone is insufficient. 1
Do not attribute a markedly prolonged block solely to “individual variation” without investigating for underlying complications. 1
Early imaging (ideally within 8–12 hours) is critical when a compressive hematoma is suspected, as delayed diagnosis can lead to permanent neurological injury. 1