Subdural Displacement of an Epidural Catheter With Spinal Cord Compression in a Patient With Chronic Cancer Pain: A Case Report.

Here we present the case of a 76-year-old woman with pancreatic cancer receiving epidural analgesia for chronic cancer pain treatment. Attempts of running the epidural catheter sequentially resulted in unexpected and extensive sensory block together with sympathicolysis but insufficient pain control. Finally, after 3 failed attempts of epidural catheter placements with insufficient pain control and uncommon neurological signs, a magnetic resonance imaging (MRI) scan of the spine was ordered. The MRI showed subdural catheter displacement with extensive liquid accumulation in the subdural space and consequent significant spinal cord compression. Findings normalized after removing the subdural catheter.

Modulation of central hypersensitivity by nociceptive input in chronic pain after whiplash injury.

OBJECTIVE: Chronic pain after whiplash injury is associated with hypersensitivity of the central nervous system to peripheral stimulation. It is unclear whether central hypersensitivity is modulated by peripheral nociceptive input. We hypothesized that changes in nociceptive input would correlate with changes in magnitude of central hypersensitivity. DESIGN: Fifteen patients with chronic pain after whiplash injury were investigated. Changes in nociceptive input were induced by infiltration of painful and tender muscles with bupivacaine (0.25%). Such infiltrations produce either pain reduction or pain enhancement, the latter effect probably resulting from transient injection-induced trauma. We used this individual variability in correlation analyses. Changes in intensity of neck pain, as assessed by a visual analog scale (VAS), after infiltration were assumed to reflect changes in nociceptive input. Changes in pressure pain thresholds recorded at healthy tissues (nonpainful point of the neck and the second toe) were used to measure changes in central hypersensitivity. The correlations between the change in VAS score and changes in pressure pain thresholds 15 minutes after infiltration were analyzed. RESULTS: Statistically significant negative correlations were found between change in VAS score and changes in threshold measurements performed at the neck, but not at the toe. CONCLUSIONS: Different mechanisms underlie hyperalgesia localized at areas surrounding the site of pain and hyperalgesia generalized to distant body areas. Central hypersensitivity as a determinant of neck pain is probably a dynamic condition that is influenced by the presence and activity of a nociceptive focus.