AAN.com Talks with Gary Gronseth About New Trigeminal Neuralgia Guideline

August 19, 2008

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Gary S. Gronseth, MD, is past co-chair of the Quality Standards Subcommittee. He co-wrote the AAN’s guideline development process manual and, since 1995, has authored 19 AAN Guidelines. AAN.com met with Dr. Gronseth to find out more about the new Guideline on Trigeminal Neuralgia. He spoke with AAN.com Practice Editor Neil A. Busis, MD, FAAN.

Author Disclosure

AAN.com: What is the purpose of AAN clinical practice guidelines?

Gronseth: AAN practice guidelines—called practice parameters or technology assessments—are written to comprehensively synthesize all of the available evidence pertinent to a clinical question or a set of questions. For the purpose of developing a guideline, evidence is narrowly defined and refers to published studies of outcomes in populations of patients with neurologic diseases who undergo specific interventions. Expert opinion is excluded.

AAN.com: Who is the target audience?

Gronseth: Although AAN guidelines are used by many different groups—including non-neurology physicians and patients—the primary target is the practicing neurologist. They are developed to be as helpful as possible to neurologists caring for patients.

AAN.com: How should they be used in clinical practice?

Gronseth: AAN practice guidelines should not be viewed as prescriptive. The guidelines' fundamental purpose is not to tell a neurologist what to do. Rather, they are designed to inform the reader of the state of evidence pertaining to a specific question. We hope that the evidence synthesis will supplement the neurologist's knowledge of their patient's unique circumstances and help them make clinical decisions. Although guidelines are usually accompanied by recommendations, we try to nuance the recommendation to emphasize the strength of the evidence and to preserve physician judgment.

Some readers of guidelines are annoyed when the guideline does not make a definitive recommendation. This happens when the evidence is too weak to support recommendations. We appreciate that this is frustrating. There is a temptation in these circumstances to have experts make guideline recommendations based upon their opinions rather than based upon the evidence. The AAN does not allow this in guidelines. There are many other venues for neurologists to obtain the opinions of experts. This is not the purpose of a guideline.

AAN.com: How are they developed?

Gronseth: This is a long and sometimes arduous process that usually takes several years. A topic is nominated, often by a member of the AAN, and is presented to the AAN's guideline subcommittees—the Quality Standards Subcommittee (QSS) and the Therapeutics and Technology Assessment Subcommittee (TTA). If approved for development, the subcommittees assemble a panel of content experts and evidence-based-medicine experts. Specific clinical questions are formulated and a formalized search of the literature is undertaken to identify all the relevant evidence. The evidence is formally classified relative to its quality. Based upon the results of the identified studies and their quality, conclusions and recommendations are formulated and a draft of the guideline is submitted. The guideline goes through multiple rounds of peer review and revision. Ultimately it is reviewed and approved by the AAN Board of Directors and published in Neurology®.

AAN.com: How are potential conflicts of interest of the authors handled?

Gronseth: This is one of the most difficult areas of guideline development. We continue to improve our methods for dealing with conflicts. To ensure that pertinent clinical questions are developed and that critical studies are not missed in the literature search, it is important to have neurologists with expertise on the guideline topic on the author panel. These content experts often have conflicts. Indeed, it is virtually impossible to assemble a panel of content experts without conflicts. Since we usually cannot assemble conflict-free panels, the QSS and TTA strive to assemble panels that are balanced. That is, for every member with a conflict we have a member without a conflict. To allow the committees to identify these conflicts, prospective panel members are required to complete extensive conflict-of-interest questionnaires very early in the guideline development process. On some occasions, because of a particularly strong conflict, we may not allow a specific panel member to be the panel chair. In extraordinary circumstances, we have excluded some experts from the guideline development panel altogether.

Besides balancing the panel as much as possible, to limit the impact of conflicts of interest we adhere to a strict evidence-based process. Following this process, even experts with strong opinions cannot make conclusions or recommendations that go beyond the evidence.

AAN.com: Why was trigeminal neuralgia selected as a topic?

Gronseth: We started this process several years ago and quite honestly, although I do not recall why it was selected, most of our topics are nominated by the AAN membership. We were looking for a topic that would have international implications because we wanted to develop a guideline in conjunction with the European Federation of Neurological Societies (EFNS). Both the EFNS and AAN agreed that trigeminal neuralgia would be a good topic for the first joint guideline.

AAN.com: What are the main conclusions of this new guideline?

Gronseth: The major messages can be divided into those with diagnostic and those with therapeutic implications.

Diagnostically, it is reasonable to consider routinely imaging all patients with trigeminal neuralgia with head MRI to try to find those patients with symptomatic trigeminal neuralgia—i.e., their trigeminal neuralgia is caused by a tumor or multiple sclerosis. Alternatively, trigeminal reflex testing is highly accurate in identifying symptomatic trigeminal neuralgia patients. In patients with trigeminal neuralgia and normal trigeminal reflexes, MRI could be reasonably foregone.

Therapeutically, carbamazepine and oxcarbazepine are very effective medications that should be considered first-line. Other drugs have weak or no evidence of efficacy. Indeed, the evidence of efficacy of medications other than carbamazepine and oxcarbazepine is about as strong as the evidence of efficacy of surgical procedures targeting the Gasserian ganglion or microvascular decompression. The implication of this is that, if you have a patient with trigeminal neuralgia who has not responded to the first line drugs, it would be reasonable to consider sending them for a surgical intervention rather than trying them on multiple medical regimens with limited evidence of efficacy.

View all AAN Practice Guidelines.

Read more about AAN Practice Subcommittees.

Listen to a Neurology® podcast about using guidelines effectively.

Read a Neurology article on the effective use of guidelines.

Read a related article from a recent issue of Neurology Today®.

Author Disclosure

Dr. Gronseth has received speaker honoraria from Boeheringer Ingelheim, Pfizer, and GlaxoSmithKline, and has been compensated by Ortho-McNeil for serving on a safety monitoring committee.