Can retrograde intrarenal surgery (RIRS) be performed under spinal anesthesia in adult patients with renal stones, and what are the recommended block technique and peri‑operative precautions?

RIRS Under Spinal Anesthesia

Retrograde intrarenal surgery (RIRS) can be safely and effectively performed under spinal anesthesia in adult patients with renal stones, with outcomes equivalent to general anesthesia in terms of stone-free rates and complications.

Evidence-Based Recommendation

The most recent high-quality evidence demonstrates that spinal anesthesia (SA) is a viable alternative to general anesthesia (GA) for RIRS procedures. Multiple studies from 2021-2022 show comparable surgical outcomes between the two approaches 1, 2, 3.

Key Surgical Outcomes

Stone-free rates are equivalent between SA and GA:

• SA group: 75.9-85% stone-free rate
• GA group: 70.6-81% stone-free rate
• No statistically significant differences (p = 0.12-0.81) 1, 2, 3

Complication rates are similar:

• SA: 5-14.5% complication rate
• GA: 10-19% complication rate
• No difference in high-grade (Clavien-Dindo ≥3) complications 1, 2, 3

Advantages of Spinal Anesthesia

Operational benefits include:

• Shorter operating room time: Mean 72.9 minutes (SA) vs 81.6 minutes (GA), p=0.033 2
• Reduced hospital stay: Mean 2.2 days (SA) vs 3.5 days (GA), p=0.019 2
• Lower hemoglobin drop: 6.5±3.2 g/L (SA) vs 8.6±2.7 g/L (GA), p=0.012 4
• Significantly lower anesthetic cost: $183.8 (SA) vs $391.9 (GA), p<0.001 4

Block Technique

Combined spinal-epidural anesthesia (CSEA) is the preferred technique when regional anesthesia is chosen for RIRS 4. This approach provides:

• Adequate sensory blockade for the procedure
• Option for extended analgesia if needed
• Flexibility in managing intraoperative requirements

Perioperative Precautions

Patient Selection Criteria

Appropriate candidates for SA include:

• Adults >18 years with single or multiple renal stones
• Stone burden ≤20 mm (per standard RIRS indications) 5, 2
• Patients whose general health status permits neuraxial anesthesia
• Patients with comorbidities that increase GA risk 2

Contraindications to Consider

Do not proceed with SA if:

• Patient has untreated urinary tract infection 5, 6
• Unmodifiable bleeding diathesis present 2
• Standard contraindications to neuraxial anesthesia exist

Intraoperative Management

Critical monitoring parameters:

• No conversion from SA to GA was required in any of the large series (0% conversion rate across 139-250 patients) 1, 3, 7
• Renal mobility during spontaneous breathing under SA does not significantly affect lithotripsy efficacy 2
• Standard RIRS techniques apply regardless of anesthesia type

Maintain low intrarenal pressure and temperature:

• Use ureteral access sheath when feasible
• Keep irrigation pressure low
• Monitor for barotraumatic and septic complications 8

Postoperative Considerations

Pain management:

• Visual analog scale (VAS) pain scores at 6 and 24 hours are equivalent between SA and GA groups 4
• Standard multimodal analgesia protocols apply

Follow-up protocol:

• Imaging (ultrasound and KUB X-ray) at 2 weeks to assess stone clearance 7
• Follow-up until day 90 from discharge 1, 3

Common Pitfalls to Avoid

1. Do not assume SA is inferior: The evidence clearly shows equivalent efficacy and safety
2. Do not delay treatment for GA availability: SA can be used in day surgery settings effectively 7
3. Do not overlook patient preference: Shared decision-making between anesthesiologist and patient is appropriate 2
4. Do not proceed without proper preoperative evaluation: Obtain urinalysis/urine culture and treat any infection before surgery 6, 5

Clinical Context

While current EAU and AUA guidelines do not specifically address anesthesia choice for RIRS (focusing instead on contraindications to general anesthesia for ureteroscopy 5), the research evidence strongly supports SA as a safe alternative. The choice between SA and GA should be based on:

• Patient comorbidities and anesthetic risk
• Patient preference
• Institutional expertise
• Economic considerations
• Availability of resources

The key takeaway: Spinal anesthesia should not be considered a compromise but rather an equivalent option for RIRS, particularly advantageous in patients with increased GA risk, in day surgery settings, and when cost-effectiveness is a consideration.