[Delivery and analgesia of labouring women with congenital spine abnormalities].

Congenital spine abnormalities are common. These anomalies can be associated with other anomalies and different degrees of symptom severity. In pregnant women multidisciplinary planning and considerations of special needs may be necessary as summarised in this review. Recommendation for caesarean section should, for most parts, be made on obstetric indication only. Neuroaxial analgesia during birth and anaesthesia for caesarean section is seldom contraindicated in women with back abnormalities. However, in tethered cord, it is important to avoid iatrogenic damage to the conus when placing spinal anaesthesia.

Low-frequency electrical stimulation induces long-term depression in patients with chronic tension-type headache.

Repetitive low-frequency electrical stimulation (LFS) induces pain inhibition in healthy volunteers and in animals, but it is unknown whether it has an analgesic effect in patients with headache. The aim of this study was to investigate if LFS could induce prolonged pain inhibition, called long-term depression (LTD), in patients with chronic tension-type headache (CTTH). Twenty CTTH patients and 20 healthy volunteers were exposed to 20 min LFS (1 Hz) to the forehead. LTD was measured as a decrease in pain response to electrical stimulation in a 1-h post-LFS period following LFS. The LFS induced a significant and stable inhibition of pain (LTD) both in patients with CTTH (post-LFS average decrease in pain rating: 19.6 +/- 3.9%, all P < 0.005, Holm-Sidak) and in healthy controls (30.1 +/- 5.0%, all P < 0.001, Holm-Sidak). During the LFS period, the pain ratings decreased consistently in both groups. In conclusion, a significant and stable pain inhibition (LTD) can be induced in CTTH patients by LFS.

Central pain processing in chronic tension-type headache.

OBJECTIVE: Chronic tension-type headache (CTTH) affects 3% of the population. Directly and indirectly it causes high costs and considerable loss of quality of life. The mechanisms of this disorder are poorly understood and the treatment possibilities are therefore limited. The blink reflex (BR) reflects neuronal excitability due to nociceptive input in the brainstem. The aim of this study was to investigate nociceptive processing at the level of the brainstem in an experimental pain model of CTTH symptoms. METHODS: The effect of conditioning pain, 5 min infusion of hypertonic saline into the neck muscles, was investigated in 20 patients with CTTH and 20 healthy controls. In addition, a pilot study with isotonic saline was performed with 5 subjects in each group. The BR was elicited by electrical stimuli with an intensity of four times the pain threshold, with a superficial concentric electrode. We measured the BR, sensibility to pressure and electrical pain scores before, during and 25 min after the saline infusion. RESULTS: The pain rating of the electrical stimuli and the pain score of the hypertonic saline infusion were significantly higher in CTTH patients than in healthy volunteers. The primary endpoint was the relative change of the blink reflex integral immediately after hypertonic saline infusion. It was significantly smaller in CTTH patients on the contralateral side (-24.5% +/-7.0 (sem)) compared to healthy volunteers (0.4% +/-6.8), (p<0.05, Holm-Sidak), while there was no significant difference on the ipsilateral side (-5.9% +/-3.2 vs. -3.4% +/-3.0, n.s., Holm-Sidak). CONCLUSION: There was no robust difference in BR integral after conditioning tonic neck pain between CTTH patients and healthy volunteers, but CTTH patients were more sensitive to nociceptive stimuli. SIGNIFICANCE: A combined homotopic and heterotopic effect of the conditioning pain onto the blink reflex could account for this finding.