Effective dermatomal blockade after subcostal transversus abdominis plane block

Area of Science:

• Anesthesiology
• Pain Management
• Regional Anesthesia

Background:

• Ultrasound-guided transversus abdominis plane (TAP) block is a common technique for postoperative pain relief after abdominal surgery.
• Local anesthetics are injected into the fascial plane between internal oblique and transversus abdominis muscles to anesthetize abdominal wall sensory nerves.
• Assessing the sensory extent of a TAP block is crucial for optimizing pain management strategies.

Purpose of the Study:

• To investigate the feasibility of assessing the dermatomal extent of sensory blockade after a bilateral subcostal TAP block.
• To determine if cold and pinprick sensations can be used to evaluate the spread of local anesthetic effect.
• To guide decisions regarding the necessary extent of the block for effective pain control.

Main Methods:

• Twenty awake patients undergoing elective abdominal surgery received bilateral subcostal TAP blocks with 20 ml of 0.5% ropivacaine.
• Sensory changes in dermatomes T4-L4 were assessed using pinprick and cold swabs at 10, 20, and 30 minutes post-injection.
• Data from 40 blocks were analyzed to evaluate the dermatomal spread of anesthesia.

Main Results:

• Eighteen out of twenty patients demonstrated sensory changes following the TAP block.
• A consistent blockade of dermatomes T10-T12 was observed in all patients with sensory changes after 30 minutes.
• Variable spread of sensory blockade was noted, extending to dermatomes T5-L3 in some cases.

Conclusions:

• The study confirms that cold and pinprick sensations are reliable methods for assessing the dermatomal extent of sensory blockade after a single-shot subcostal TAP block.
• This assessment can provide valuable information for tailoring the block's extent to individual patient needs.
• The findings support the use of sensory testing to optimize postoperative pain management with TAP blocks.