Results of the Treatment of Chronic, Refractory CRPS with Ketamine Infusions: a Preliminary Report

Abstract

Chronic, refractory complex regional pain syndrome remains very difficult to treat. A sub-anaesthetic low-dose ketamine has shown promise in advanced CRPS. We investigated the efficacy of ketamine in anaesthetic dosage in chronic, refractory CRPS patients that had failed available standard therapies. 5 female patients, aged a mean of 34 years with long-standing, a mean of 8 years’, CRPS received ketamine in anaesthetic dosage over 10 days. The patients received 1–5 ketamine courses. The effect of gradual pain reduction was observed beginning on the 4^th–5^th day of treatment, associated with a decrease in the intensity of the allodynia (pain at light touch). No improvement in function (finger range of motion, grip strength) of the affected hands was noted in any patient. This beneficial analgesic effect was confined to 1.5–2.5 months after treatment and then pain relapsed to the baseline level. The results of this study show a short-term analgesic effect for this therapy, with no effect on movement and function of the affected limbs. Nevertheless, this method brings hope to the most severely ill patients who cannot be offered any other reasonable treatment option.

Zusammenfassung

Das chronische, therapieresistente komplexe regionale Schmerzsyndrom (CRPS) ist weiterhin schwierig zu behandeln. Niedrigdosierte Ketamingaben zeigten in solchen Fällen vielversprechende Ergebnisse. Wir untersuchten die Effektivität von Ketamin in anästhesierender Dosierung bei Patienten mit einem chronischen, therapieresistenten komplexen regionalen Schmerzsyndrom, bei denen die herkömmliche Behandlung versagte. 5 weibliche Patienten mit einem mittleren Alter von 34 Jahren und einem im Mittel seit 8 Jahren bestehenden CRPS erhielten Ketamin in anästhesierender Dosierung über 10 Tage, wobei zwischen 1 und 5 Zyklen verabreicht wurden. Nach 4–5 Tagen wurde eine graduelle Schmerzreduktion beobachtet – begleitet von einer Verminderung der Berührungsempfindlichkeit, allerdings ohne funktionelle Verbesserung (Fingerbeweglichkeit, Griffkraft). Die Schmerzreduktion hielt zwischen 1,5 und 2,5 Monate an. Danach kehrten die Schmerzen auf das Ausgangsniveau zurück. Zusammenfassend kam es also zu einem kurzfristigen Absinken der Schmerzen ohne funktionelle Verbesserung. Trotzdem gibt uns dieser Behandlungsansatz Hoffnung für jene Patienten mit einem CRPS, bei denen alle anderen Behandlungsversuche fehlgeschlagen sind.

Key words

chronic regional pain syndrome - ketamine infusion

Schlüsselwörter

chronisches regionales Schmerzsyndrom - Ketamin-Behandlung

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