Lecture: Segmented Spinal Anesthesia

Introduction

• Speaker: Thankful for the opportunity presented by ISACON Kerala
• Topic: Segmented spinal anesthesia
• Historical Context: Introduced in 2006 by A. van Zundert for a patient with severe COPD during laparoscopic polycystectomy.
• Evolution: From criticism to acceptance and appreciation as a regional anesthetic technique.

Concept of Segmented Spinal

• Definition: Spinal anesthesia near targeted nerve roots using low volumes of local anesthetic.
• Technique: High lumbar or thoracic dural puncture to achieve a true segmental block.
• Physiological Factors:
  • Natural thoracic kyphosis
  • Thin thoracic nerve roots favoring efficient blockade
  • No difference in onset time between isobaric and hyperbaric drugs at thoracic levels

Safety Concerns

• Neurological Injury: Major concern; spinal cord damage risk
  • MRI findings: Spinal cord positioned anteriorly in thoracic region with more space between posterior dura and spinal cord.
• Ventilatory Impairment: Unaffected diaphragm; only potential expiration and coughing affected.
• Heart Rate and Blood Pressure:
  • Bradycardia due to blocks extending T1 to T4
  • Less hypotension due to limited sympathetic blockade and lower drug volume

Feasibility and Applications

• Feasibility: Technically feasible, economical, and practical in skilled hands.
• Applications:
  • Intraoperative surgeries in prone/lateral positions, thoracolumbar/musculoskeletal surgeries, breast, and some thoracoscopic procedures.

Techniques and Combinations

• Single Shot: For short to mid-duration surgeries
• Combined with Epidurals: For longer duration surgeries
• Continuous Segmented Spinal: Using SpinoCats
• Drug Types:
  • Isobaric and hyperbaric drugs used; each has advantages and limitations

Advantages

• Higher block levels with lower doses
• Stability in cardiovascular function
• Early recovery and ambulation
• Reduced post-op complications, especially in respiratory comorbid patients

Drug Characteristics

• Isobaric Drugs: Gradual onset, selective anesthesia, shorter motor block time
• Hyperbaric Drugs: Used in specific muscular patients settings
• Additives: Enhance sensory blocks (e.g., fentanyl, dexmedetomidine)

Dosage Strategies

• Depends on surgery type, duration, and patient comorbidities
• Example: 2-2.5 ml drug blocks segments from T2 to L5 S1 if given at T10

Safety and Risks

• Litigation Concerns: Limited due to growing evidence but requires caution and informed consent.
• Practical Tips:
  • Consider ultrasound guidance for difficult cases
  • Ensure complete pre-anesthetic evaluation

Summary

• Outcome: Positively transforming anesthesia practices
• Current Status: Increasingly popular, significant safety profile if due precautions are taken
• Visual Aids: Videos and images enhance understanding and acceptance

Conclusion

• Acknowledged colleagues and researchers
• Encourages continued research and application in clinical practice