Is epilepsy surgery utilized to its full extent?

Authors


To the Editors:

In 2001, Engel stated that surgery in patients with drug-resistant focal epilepsy is one of the most neglected successful treatments worldwide (Engel, 2001). Guidelines advise screening for epilepsy surgery in patients with persistent seizures after 2 years of medical treatment, when two or three first-line antiepileptic drugs have failed (Engel et al., 2003; Karceski et al., 2005; Van Donselaar & Carpay, 2006). Six years later, we investigated whether epilepsy surgery is still underutilized and, if so, why.

From a general, nonacademic hospital and a tertiary epilepsy clinic in The Netherlands, we collected a random sample of all adult patients who were not seizure free despite medical treatment (Fig. 1). The files of the patients not referred for presurgical work-up were evaluated by a panel of two independent experienced epileptologists who determined whether the patients were correctly not referred, whether they were potential candidates for work-up but additional diagnostic tests (e.g., MRI according to special epilepsy protocol or video EEG monitoring) were indicated, or whether they were straightforward true candidates.

Figure 1.


Flow chart of evaluated patients.

Results are presented in Fig. 1. In the general hospital, 31 of the 427 evaluated patients were not referred for presurgical work-up, although they should have been according to the guidelines, while seven patients were correctly referred. In tertiary care, this distribution was 42 of 160 patients not referred and 15 referred. The expert panel concluded that of the 73 (31 + 42) nonreferred intractable patients, four (two from secondary and two from tertiary care) were true candidates for presurgical work-up and 12 (eight from secondary and four from tertiary care) were potential candidates pending further testing. In total, there were 16 incorrectly nonreferred patients.

In secondary care, 10 additional (two true and eight potential) candidates were incorrectly not referred, which means that the referral rate should have been 1.3 ([7 + 2]/7) to 2.4 ([7 + 2 + 8]/7) times higher than currently. In tertiary care, six additional (two true and four potential) candidates were eligible for referral, leading to a 1.1 ([15 + 2]/15) to 1.4 ([15 + 2 + 4]/15) times higher referral rate. Overall, instead of 22 patients, at least 26 (22 + 4) and at the most 38 (22 + 4 + 12) of 587 evaluated patients should have been referred—that is, 4–6% of the outpatient epilepsy patients. This rate is slightly higher than the 3% Lathoo et al. estimated for the United Kingdom (Lhatoo et al., 2003).

In the 16 nonreferred patients, mean time since failure of a third drug was 5.7 years (median = 4.3; range = 0.3–19.6). When asked, caring neurologists gave as a main reason for not referring that they considered the seizure burden as low. Some secondary care patients had been referred to a tertiary care clinic, but in tertiary care the possibility for presurgical work-up was not raised.

In conclusion, physicians in secondary and tertiary care do not sufficiently adhere to guidelines for referral to presurgical work-up. We believe that better use of available noninvasive diagnostic facilities should be encouraged, so as to facilitate appropriate referral to presurgical work-up.

Acknowledgment

This study was supported by a grant from the Dutch College of Health Insurers (CVZ). The study sponsor had no involvement in the study design; in the collection, analysis, and interpretation of the data; in the writing of the report; and in the decision to submit the paper for publication.

Conflict of interest: The authors confirm that they have read the Journal's position on issues involved in ethical publication and affirm that this report is consistent with those guidelines. In addition, the authors report no conflicts of interest.

Ancillary