As outpatient orthopedic surgery becomes increasingly prevalent, the choice of spinal anesthetic plays a pivotal role in optimizing patient recovery and healthcare resource use. Traditionally, bupivacaine has been the mainstay agent due to its profound block and long duration. However, mepivacaine, with its shorter and more predictable action, is emerging as an appealing alternative, particularly in same-day discharge total joint arthroplasty (TJA).

A 2024 quality improvement study by Coleman et al., published in Regional Anesthesia & Pain Medicine, explored this very shift at a large academic medical center. The results reveal a compelling story of trade-offs between operational efficiency and patient comfort.

The need for speed: why anesthetic choice matters

In the context of bundled payment models, hospital capacity limits, and the aftermath of COVID-19 backlogs, same-day discharge after TJA has become a high-value target. With surgical techniques and patient optimization already refined, attention is turning toward anesthetic agents that can support early ambulation and rapid PACU turnover.

Key goals for spinal anesthesia in outpatient TJA:

• Provide reliable sensory and motor blockade during surgery
• Minimize postoperative side effects (nausea, urinary retention)
• Allow predictable, timely return of motor function
• Facilitate discharge from PACU without delay

Key findings: Mepivacaine accelerates recovery, but increases discomfort

1. Shorter PACU time

• Bupivacaine group: Median 5.33 hours
• Mepivacaine group: Median 4.03 hours
• Statistical significant

Interpretation: A reduction of over 1 hour in median PACU time supports increased throughput and efficiency, especially crucial in settings with high patient volume or limited PACU beds.

2. Higher postoperative pain scores

• Maximum PACU pain score:
  • Bupivacaine: 3.41
  • Mepivacaine: 6.29
• Pain at PACU discharge:
  • Statistically higher in the mepivacaine group

Takeaway: The faster resolution of mepivacaine can lead to earlier return of nociception and discomfort, necessitating more vigilant pain management in PACU.

3. Increased opioid use

• Perioperative OMME:
  • Bupivacaine group: Mean 11.4 mg
  • Mepivacaine group: Mean 22.5 mg
• Statistically significant

Clinical note: Despite faster discharge, patients receiving mepivacaine required nearly double the opioid analgesia, raising concerns about early postoperative pain and potential for overmedication.

4. Similar safety outcomes

• Conversion to GA: No significant difference
• Overnight admission: One per group
• Emergency department visit: One in the bupivacaine group for nausea and pain

Conclusion: Switching agents did not increase the rate of anesthesia-related complications or unplanned admissions.

Practice implications: weighing benefits and trade-offs

Benefits of mepivacaine:

• Predictable block resolution
• Faster patient turnover in PACU
• Enhanced capacity for elective surgeries

Drawbacks:

• Increased postoperative pain
• Greater opioid requirements
• More challenging PACU pain control

Strategies for success

• Preoperative education: Set expectations for faster return of sensation and the need for prompt pain control
• Aggressive multimodal analgesia: Consider NSAIDs, acetaminophen, and regional nerve blocks
• PACU staffing awareness: Inform nursing and physical therapy teams of anesthetic choice and timing

Conclusion

Coleman et al.’s study offers valuable real-world evidence that switching to intrathecal mepivacaine can meaningfully improve discharge efficiency in same-day TJA. However, it introduces new challenges in managing early postoperative pain and opioid consumption. Institutions considering this transition must weigh the benefits of reduced PACU time against the cost of increased analgesia needs and discomfort.

Reference: Coleman PW et al. Transitioning from intrathecal bupivacaine to mepivacaine for same-day discharge total joint arthroplasty: a quality improvement study. Reg Anesth Pain Med. 2024;49:254-259.

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