[Unilateral spinal anesthesia : Literature review and recommendations]

Area of Science:

• Anesthesiology
• Regional Anesthesia
• Surgical Patient Management

Background:

• Unilateral spinal anesthesia provides targeted anesthesia with fewer adverse effects than bilateral spinal anesthesia.
• It is particularly advantageous for patients with cardiovascular risks, avoiding hypotension common in bilateral techniques.
• The technique is suitable for outpatient surgery, addressing limitations of traditional spinal anesthesia like prolonged recovery and urinary retention.

Purpose of the Study:

• To review and define an optimized method for performing unilateral spinal anesthesia.
• To highlight the benefits of unilateral spinal anesthesia for outpatient procedures and specific patient populations.
• To establish key parameters for achieving a successful and exclusively unilateral block.

Main Methods:

• A review of published data on unilateral spinal anesthesia from high-impact factor journals.
• Definition of an optimized technique focusing on anesthetic agent, dose, baricity, needle type, injection speed, and patient positioning.
• Specific recommendations include using 0.5% hyperbaric bupivacaine, slow injection (≤0.33 ml/min), and maintaining lateral decubitus position for 20 minutes post-injection.

Main Results:

• A dose of 5 mg of 0.5% hyperbaric bupivacaine provides a block to T12 for one hour.
• Doses of 7.5-10 mg extend the block to T6.
• Adding clonidine (0.5-1.0 µg/kg) prolongs the block duration to 2-3 hours; patient positioning influences cephalad spread.

Conclusions:

• Unilateral spinal anesthesia is a cost-effective, rapid technique with significant advantages over bilateral spinal anesthesia.
• Optimized technique ensures an exclusively unilateral block, minimizing side effects and allowing for earlier patient discharge.
• This method enhances suitability for outpatient surgery and patients with cardiovascular comorbidities.