Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Jan 2004
Comparative Study Clinical TrialThigh rotation and the anterior approach to the sciatic nerve: a magnetic resonance imaging study.
The anterior approach to the sciatic nerve block may be associated with a high failure rate because the nerve lies posterior to the lesser trochanter of the femur at the level of needle insertion. However, previous work using cadavers demonstrated that internal rotation of the leg renders the nerve more accessible to the anterior approach. ⋯ The results confirm that, as the thigh is moved from an externally to an internally rotated position, the sciatic nerve becomes more accessible by the anterior approach at the level of the lesser trochanter, and the risk of femoral artery or nerve puncture is reduced but not eliminated.
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Reg Anesth Pain Med · Jan 2004
Case ReportsAccidental subdural injection during attempted lumbar epidural block may present as a failed or inadequate block: radiographic evidence.
Until now, case reports after accidental subdural injection during attempted epidural block have usually described extensive neuraxial blocks with a delayed onset, after low doses of local anesthetic, with a characteristic radiographic appearance on contrast injection. Our radiographic investigation of atypical "epidural" blocks has revealed that subdural injection may go unrecognized clinically and may be a cause of inadequate blocks. The mechanism is explored. ⋯ Accidental subdural injection may now be added to the list of causes of failed or inadequate "epidural" block. Clinicians should be aware of the diagnosis of a possible subdural injection, if a poor quality block with restricted spread and slow onset is associated with pain on postoperative reinjection of the catheter.