Authors' objectives:

This report aims to evaluate the state of the art of double-electrode medullary electrostimulation (MES) with a view to considering its inclusion in the CatSalut surgical services catalogue.

It synthesises the results on the efficacy/effectiveness and safety of the MES systems in failed back surgery syndrome. The evaluation report presents the results of the other endpoints analysed (description of the MES system, needs analysis, description of the available alternatives, economic analysis of MES and context analysis).

Authors' results and conclusions: 1. Efficacy/effectiveness of double-electrode MES in failed back surgery syndrome: The scientific evidence published on the effectiveness of double-electrode MES is limited (15 studies, of which 6 are congress abstracts) and classified in the scientific evidence level VIII (quality of the evidence: low) since it is a before/after design where each patient acts as their own control (13/15 studies) and, therefore the degree of recommendation is C, i.e. there is insufficient scientific evidence for recommending the adoption of double-electrode MES in failed back surgery syndrome. Nevertheless, in this indication there are results of a crossover prospective randomised trial comparing the MES with a semi-implanted single-electrode system and correctiv neurosurgery. According to this trial, and after 36 months of follow-up of 90% of the patients included (n=50), 52% of the patients with permanent implant presented successful results (pain relief of at least 50%) in comparison with the 19% observed in patients re-operated.6 In this case, the level of scientific evidence is III (quality of scientific evidence good) depending on the type of design and, therefore, degree A of recommendation. Despite this, although there is suitable scientific evidence to recommend the adoption of single-electrode MES simple in failed back surgery syndrome, it must be mentioned that it is only one study, that the sample is small and that was it was performed in a single centre (so for the moment there is absence of reproducibility). The size of the mean sample of the 15 studies is 42 patients, and follow-up varies between 3-48 months. In these studies on the double electrode, the MES systems implanted with greatest frequency are the semi-implantables. Nevertheless, in some it is not possible to distinguish the results according to the type of implant used and the implanted models are not to be found on the market at the moment. According to these published studies, a considerable percentage of patients present post-implant pain relief, coincidence of paresthesia with most of the target area, reduction in the use of analgesics and opiates, and improved sleep patterns (more hours of sleep a day and fewer night-time awakenings). These effects, while reduced over time, seem to be conserved in a certain percentage of patients. After the implant, an improvement in the patients health-related quality of life is also observed and generally speaking patients rate effects on pain control favourably, and are satisfied with the MES and would be willing to repeat. 2. Safety of double-electrode MES: The percentage of mechanical complications or those related with the double-electrode MES is quite variable (7-55.5%) and often higher than surgical complications (0-25%), which are not very serious. No deaths related with the double-electrode MES have been described, nor with the single-electrode system, at least for the indication studied. Explantation (removal of the implant) may be prompted for different reasons such as loss of pain control or presence of possible troublesome positional stimulations. The frequency of implant removal is very variable in the studies that report it.

Authors' recommendations: It is considered that double-electrode MES may be provided in the surgical services catalogue of CatSalut, where single-electrode MES is already included, although there are still limitations in terms of its evaluation and the type of patient to treated. The inclusion of specific brands in this catalogue is not deemed convenient. In any event, if the specification of one of these products must be provided for in the catalogue, the type of MES (single-electrode and/or double electrode) must be described, and the maximum price at which the CatSalut will reimburse this product given.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.gencat.net/salut/depsan/units/aatrm/html/en/dir393/doc7921.ht ml

Year Published: 2003

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: Spain

Organisation Name: Agencia de Qualitat i Avaluacio Sanitries de Catalunya

Contact Address: Antoni Parada, CAHTA, Roc Boronat, 81-95 (2nd floor), 08005 Barcelona, Spain, Tel. +34 935 513 928, Fax: +34 935 517 510

Contact Name: direccio@aatrm.catsalut.net / aparada@aatrm.catsalut.net

Contact Email: direccio@aatrm.catsalut.net / aparada@aatrm.catsalut.net

Copyright: Catalan Agency for Health Technology Assessment and Research (CAHTA)