OBJECTIVES: The intrathecal route has not yet been thoroughly standardized and evaluated in an experimental model of spinal cord injury (SCI) in Wistar rats. The objective of this study was to standardize and evaluate the effect of intradural injection in this animal model. METHOD: The animals were divided into 6 groups: 1) laminectomy and intradural catheter; 2) laminectomy, intradural catheter and infusion; 3) only SCI; 4) SCI and intradural catheter; 5) SCI, intradural catheter and infusion; and 6) control (laminectomy only). Motor evaluations were performed using the Basso, Beattie and Bresnahan (BBB) scale and the horizontal ladder test; motor evoked potentials were measured for functional evaluation, and histological evaluation was performed as well. All experimental data underwent statistical analysis. RESULTS: Regarding motor evoked potentials, the groups with experimental SCI had worse results than those without, but neither dural puncture nor the injection of intrathecal solution aggravated the effects of isolated SCI. Regarding histology, adverse tissue effects were observed in animals with SCI. On average, the BBB scores had the same statistical behaviour as the horizontal ladder results, and at every evaluated timepoint, the groups without SCI presented scored significantly better than those with SCI (p<0.05). The difference in performance on motor tests between rats with and without experimental SCI persisted from the first to the last test. CONCLUSIONS: The present work standardizes the model of intradural injection in experimental SCI in rats. Intrathecal puncture and injection did not independently cause significant functional or histological changes.

A fibrose pós laminectomia em cirurgias da coluna vertebral tem sido responsabilizada por um grande percentual das falhas nestas cirurgias, tanto a curto quanto a longo prazo. Muitos dos pacientes desenvolvem sintomas de dor crônica ou recorrente após tratamento cirúrgico de hérnias de disco, estenose de canal, etc. Apesar de ainda existirem dúvidas quanto à fisiopatologia do problema, sabe-se que a fibrose interfere na mobilidade normal das raízes e da medula espinal, fator este responsabilizado como o principal na gênese das falhas cirúrgicas. Para se evitar a fibrose pós-cirúrgica, vários materiais de interposição entre a musculatura posterior da coluna e a dura-máter foram estudados, sem grandes resultados. Neste trabalho foi feito o estudo da membrana de politetrafluoroetileno inerte expandido (Preclude Spinal Membrane®) comparando-se a mesma com grupo controle para a prevenção da fibrose pós laminectomia. Observou-se que a técnica cirúrgica apurada parece ser fator importante na prevenção da formação de tecido cicatricial abundante e que a membrana de politetrafluoroetileno inerte expandido mostrou ser material inerte.

Post laminectomy fibrosis in spine surgery has been responsible for a high rate of failure in a short or long term. Many of this patients develop chronic or recurrent pain after surgery of discal herniation, canal stenosis etc. Although there some doubts about the etiology of this problem, it was known that fibrosis interfere with the normal mobility of roots and spinal cord. This factor is considered as the most important aspect in the genesis of the surgical failures. To avoid postoperative fibrosis, a lot of materials of interposition between posterior spine muscles and dura mater were studied, without good response. This paper studied comparatively post laminectomy fibrosis in Wistar rats with the addition of the following materials to avoid it: control group (without interposition) and expanded inert polytetrafluoroethylene membrane (Preclude Spinal Membrane®). It was observed that accurate surgical technique apparently is an important factor to prevent the formation of abundant scar tissue and that the expanded inert polytetrafluoroethylene membrane is an inert material.

O uso de agentes morfínicos para o controle da dor crônica não relacionada a câncer é controverso. Este estudo aferiu o alívio da dor e as mudanças nas atividades de 11 doentes com dor crônica não associada ao câncer, tratados pela infusão intratecal de fármacos morfínicos através de bombas implantáveis. A dor era neuropática em 5 doentes e miofascial em 6. A duração média da queixa álgica foi 5,3 anos. A média da intensidade da dor antes da infusão foi 8,6. Sete doentes apresentavam dor durante 6 ou mais horas por dia. Após o tratamento, a média de intensidade da dor reduziu-se para 3,9. Somente 1 doente manteve dor com duração superior a 6 horas. O tratamento melhorou o desempenho de 36,36% dos aspectos funcionais avaliados. O tempo médio de tratamento foi 19,6 meses. A infusão crônica de agentes morfínicos por via intratecal proporcionou alívio da dor, mas não melhorou a funcionalidade com a mesma magnitude.

The use of opioids for treatment of non-malignant pain is controversial. The evaluation of pain relief and of the quality of life of 11 severely incapacitated chronic non-cancer pain patients treated with long term intrathecal infusion of opioids trought implantable pumps was performed. The mean duration of pain complaints was 5.3 years. The mean pain intensity was 8.6. In 7 patients, pain episodes lasted at least 6 hours daily. The mean duration of the therapy was 19.6 months. After the treatment the mean pain score became 3.9. In only 1 patient, the duration of pain episodes was still longer than 6 hours. Quality of life improved in 36.36% of the cases. The long term spinal opioids through implantable pumps for non-malignant pains results in pain relief but not necessarily improves the quality of life.