Pain
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Comparative Study Clinical Trial
Long-term cohort study comparing medical (oxcarbazepine) and surgical management of intractable trigeminal neuralgia.
Trigeminal neuralgia is a recurrent severe shooting neuropathic pain which can be managed both pharmacologically and surgically. However, there are no prospective data that compare these two therapeutic strategies. This study therefore aimed to assess long-term outcome in patients with intractable trigeminal neuralgia treated with oxcarbazepine and later with surgery. ⋯ Surgery does not provide pain relief for all patients. This is the first study that has compared outcome in a group of patients who have had both pharmacological and surgical treatments. As these data cannot be extrapolated to other antineuralgic drugs, similar comparative studies would be appropriate.
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To study the role of inflammatory cytokines in the initiation and persistence of radiculopathy as seen in humans, tumor necrosis factor alpha (TNF-alpha) was administered either to normal, uninjured L5 dorsal root ganglia (DRG) of rats via a hole drilled through the transverse process, or to chronically compressed L5 DRG via a hollow stainless steel rod inserted into the intervertebral foramen. In other experiments, a mixture of soluble TNF receptors (sTNF-Rs: sTNF-RIplus minussTNF-RII) was locally delivered to the chronically or acutely compressed DRG to neutralize the activity of endogenous TNF-alpha. Behavioral tests of mechanical allodynia were performed before and after TNF-alpha administration. ⋯ Similar results were obtained when sTNF-Rs were chronically administrated at the acutely compressed ganglion. Results demonstrated that exogenous TNF-alpha causes pain and mechanical allodynia when deposited at the normal DRG, and further enhances the ongoing allodynia when administrated at the compressed DRG. Results also suggest that endogenous TNF-alpha contributes to the early development of mechanical allodynia in rats with chronic DRG compression.
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After transection of the inferior alveolar nerve (IAN: the third branch of the trigeminal nerve), the whisker pad area, which is innervated by the second branch of the trigeminal nerve, showed hypersensitivity to mechanical stimulation. Two days after IAN transection, the threshold intensity for escape behavior to mechanical stimulation of the ipsilateral whisker pad area was less than 1.0 g, a sign of allodynia, and returned to the preoperative level (preoperative threshold: 52.0 g) at 32 days after surgery. This decrement of escape threshold lasted for more than 3 weeks. ⋯ Furthermore, an extensively greater number of Fos protein-LI cells were expressed both in superficial and deep laminae of the bilateral Vc and C1 of the spinal cord after subcutaneous injection of mustard oil into the whisker pad. Fos protein expression after mustard oil injection was much stronger than that observed after any mechanical stimulation in the rats with IAN transection. These data suggest that the change in the numbers and spatial arrangement of nociceptive neurons in the Vc and C1 after IAN transection reflect the development of mechanical hyperalgesia in the area adjacent to the IAN innervated region.