Guidelines for return to driving

Our initial search yielded a total of 85 articles across databases after excluding duplicates (Figure 1). Two articles met the inclusion criteria.

Figure 1.

Flow diagram of the article selection process from the Medline (Ovid), Embase and PubMed databases.

• • Charmley et al. aimed to provide return to driving guidelines following deep brain stimulation surgery.^{Reference Charmley, Kimber, Mahant and Lehn12} They highlighted sparse literature and supporting data. They advised a period of 6 weeks without driving for personal vehicles, while patients operating commercial vehicles were advised to wait 6 months prior to resuming driving. In both instances, surgery and the associated recovery had to be uneventful and the underlying disease controlled. Disease control was defined as adequate management of symptoms that might affect driving performance (e.g., cognitive dysfunction, motor symptoms and excessive daytime sleepiness).

• • Cho et al. reported results of a survey examining practice patterns of Australian and New Zealand neurosurgeons regarding the utilization of Prophylactic Antiepileptic Drugs and recommendations for driving restrictions following craniotomy surgery in patients without a history of seizures.^{Reference Cho and Olson13} Driving restrictions varied among respondents, but the most common driving restriction recommendation following craniotomy was 6 months, consistent with the Austroads recommendations.^{Reference Cho and Olson13} There was some variability in recommendations, as restriction durations stated by Austroads are advisory and the decision is ultimately left to the clinician.

Review of guidelines in G20 countries

Table 1 summarizes recommendations for return to driving following cranial procedures in G20 countries. Our review identified three national guidelines for return to driving after a craniotomy (New Zealand, Australia and the United Kingdom). We also found local recommendations on the website of individual institutions. New Zealand’s guidelines suggested waiting at least 3 months before resuming driving following a craniotomy for patients presenting without seizures; 6 months was recommended if a craniotomy was performed for a brain tumor.¹⁴ Australia recommends that driving be avoided for 6 and 12 months for personal and commercial vehicles, respectively.¹⁵ The UK DVLA has a comprehensive guideline for return to driving after a craniotomy, which stratifies based on pathology¹⁶ (see Table 2). For instance, following a craniotomy to remove a meningioma, the recommendations for the return to driving depend on the meningioma’s pathological grade: 6 months without seizure for grade 1, 12 months if grade 2 and 24 months if grade 3. Similarly, following craniotomy for glioma resection, the recommendation is to wait 12 months without seizure if the pathology is low grade (WHO 1 or 2) and 24 months if the pathology is high grade (WHO 3 or 4). In contrast, patients who have undergone transsphenoidal surgery for pituitary adenoma, infratentorial craniotomy for low-grade tumors or craniotomy for unruptured aneurysms can return to driving immediately without consideration for postoperative seizure.¹⁶

Table 1.

Recommendations for return to driving following uncomplicated cranial procedures in countries of the G20

* The recommendations provided by the Driving and Vehicle Licensing Agency of these countries refer specifically to the postoperative seizure risk in patients who do not have a prior history of seizures or significant neurological impairment.

Table 2.

Recommendations for return to driving following cranial procedures from the UK Driving and Vehicle Licensing Agency¹⁶

Select academic institutions have developed specific driving protocols that were not captured in the aforementioned search.¹⁷ One such protocol from the University of Colorado Denver recommends that patients resume driving after 1 week if they have never experienced a seizure, are no longer on narcotic pain medication and have no neurological impairments.¹⁷ While Canada lacks formal national recommendations, some institution-specific guidelines exist.^18,19 For instance, the University Health Network, Toronto, Ontario, suggests that patients should avoid driving for at least 2 weeks after craniotomy surgery.¹⁹ The institutional recommendation at the University of Montreal Hospital Center¹⁸ (Montreal, Quebec) is to avoid driving for at least 2 months after craniotomy surgery.

Risk of seizures following a craniotomy

We performed a scoping review to determine seizure risk following craniotomy.^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9,Reference Horiuchi, Kanaya and Horiuchi20–Reference Kuijlen, Teernstra, Kessels, Herpers and Beuls34} Most studies stratified postoperative seizures as “early” (in the first week after surgery) and “late” (more than 1 week after surgery). Approximately half of postoperative seizures occurred early.^{Reference Horiuchi, Kanaya and Horiuchi20,Reference Ersoy, Ridwan, Grote, Coras and Simon22,Reference Baumgarten, Sarlak and Monden24,Reference Zheng, Chen and Fu31,Reference Bogdanovic, Ristic and Ilic32} Most studies had a small sample size (n < 100), included patients with preoperative epilepsy and had variable durations of follow-up. However, a single study had a sufficient sample size to stratify the risk of postoperative seizures based on etiology, as well as a sufficient follow-up to estimate the chance of occurrence of seizure in the next year (COSY) required to calculate an accident risk ratio (ARR) and formulate driving recommendations.^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9} Giraldi et al. recently reported a nationwide register-based cohort study in Denmark where they evaluated postoperative de novo epilepsy after craniotomy.^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9} They included approximately 9000 patients without prior epilepsy who underwent index craniotomy in Denmark between 2015 and 2016. They calculated the cumulative risk of de novo seizure at 6 months, 12 months and 5 years postoperatively ^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9} (summarized in Table 3). At 12 months post-craniotomy, patients had a cumulative risk of de novo epilepsy of 13.9% (which varied based on etiology). For example, the cumulative risk was 25% at 12 months for patients operated on for glioblastoma or low-grade glioma, compared to 5% for patients operated on for unruptured aneurysms.

Table 3.

Cumulative risk of postoperative de novo epilepsy after a craniotomy for various underlying pathologies, based on a national registry of 9000 patients without preoperative epilepsy (modified from Giraldi et al.^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9})

Evidence-based approach to driving recommendations and risk calculations

We used data directly from the supplementary material including in Giraldi et al. rather than performing a meta-analysis of small heterogeneous studies as we felt the rigorous, registry-based, high sample size data provided in Giraldi et al. would be more reliable and more granular for underlying pathologies. Based on current epilepsy guidelines, patients who have had a single unprovoked seizure are typically allowed to return to driving 6 months after a seizure, provided their risk of seizure recurrence in the next year is below 20%.^{Reference Brown, Lawn, Lee and Dunne35–38} Drivers can regain their “heavy (commercial) vehicle” license after 5 years, provided their risk of a recurrence is below 2%.^{Reference Brown, Lawn, Lee and Dunne35–Reference Rémillard, Zifkin and Andermann40} Although somewhat arbitrary, these recommendations are based on the calculation of patients’ ARR: the patient-specific relative risk of a motor vehicle collision compared with the general population.^{Reference Brown, Lawn, Lee and Dunne35,38} Many conditions and demographic characteristics may increase the ARR, for instance, being a male driver age < 25 years (ARR = 7) or age > 70 years (ARR = 2).³⁸ The European Working Group on Epilepsy and Driving concluded that in patients with epilepsy, ARR < 2 is acceptable to allow driving.^{Reference Sonnen37,38} Calculating an individual’s ARR compared to the general population can use the formula:

$$ ARR={\left(COSY \times D \times X\right) \over F+1} $$

where:

COSY = Chance of occurrence of seizure in the next 12 months (as a ratio)

D = Driving time (as a proportion of time spent driving)

X = Probability of a seizure at the wheel causing a fatal accident

F = Overall community fatal accidents per driver per year

Regarding the calculation of the ARR related to epilepsy, expert working groups have assumed a mean driving time of 1 h/day, a 1.8% risk of fatal accident if a seizure occurs at the wheels (60% accident rate, of which 3% are deadly) and an equally distributed risk of seizure among time of day and week.³⁸ The risk of fatal accident due to seizures is compared to the overall rate of community fatal accidents per driver per year (1/7000 per year).³⁸ By these calculations, if the COSY is less than 20%, the ARR related to epilepsy falls in an “acceptable” range for driving (<2). For a first seizure, a COSY < 20% is reached after 6 months without seizure, hence the general recommendation of 6 months of seizure freedom required to resume driving. When considering a permit to drive a large commercial vehicle, the epilepsy literature suggests that a COSY < 2% is required, given the higher probability that a seizure at the wheel would cause a fatal accident or even mass casualty (X variable in the formula).³⁸

If we apply these same standards to patients who undergo craniotomy, procedures that do not violate the pia (e.g., clipping of an unruptured intracranial aneurysm or resection of a grade 1 meningioma) imply a postoperative risk of seizure of <20% throughout the first 12 months (5%–10%).^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9} Therefore, an extended restriction of driving may not be warranted with regard to seizure risk in these patients; they may resume driving immediately if they do not take opioid medication and do not have significant neurological impairment. However, procedures involving a violation of supratentorial pia (e.g., resection of a glioblastoma or low-grade glioma) imply a postoperative risk of epilepsy of more than 20% in the first 12 months (20%–25%).^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9} For these patients, waiting at least 1 month before driving may be reasonable. The best available data on postoperative seizure risk after a craniotomy only provides seizure risk at 6 months, 12 months and annually thereafter; granular data is lacking for seizure risk at 1 month or 2 months postoperative, similarly at 13 months or 14 months. As such, we cannot presently calculate a precise COSY at these time points. Therefore, based on currently available data, it is not possible to precisely calculate exactly how long after craniotomy patients with higher-risk pathologies must remain seizure free to reach a COSY < 20% (hence an ARR < 2). In the literature, about half of postoperative seizures occur within the first week (“early postoperative seizures”).^{Reference Horiuchi, Kanaya and Horiuchi20,Reference Ersoy, Ridwan, Grote, Coras and Simon22,Reference Baumgarten, Sarlak and Monden24,Reference Zheng, Chen and Fu31,Reference Bogdanovic, Ristic and Ilic32} Given the high proportion of overall postoperative seizures occurring early (within 1 week), the COSY < 20% is likely reached within 1 month without seizures in all patients, even among those with higher-risk underlying conditions (e.g., high-grade glioma).^{Reference Giraldi, Vinsløv Hansen, Wohlfahrt, Fugleholm, Melbye and Munch9} Since this is an estimation not backed by primary data from Giraldi et al., we opt for a more vague and nuanced recommendation: avoiding driving for at least 1 month without seizure after a craniotomy performed for higher-risk conditions.

Regarding the driving of large commercial vehicles, the annual risk of seizure (COSY) in the first postoperative year is more than 2% for all documented conditions in Giraldi et al. except for surgeries performed for cranial nerve pathologies (e.g., microvascular decompression for trigeminal neuralgia; 1.3% at 1 year, see Table 3). For some other low-risk conditions (craniotomy for the clipping of unruptured aneurysms, congenital malformations such as arachnoid cysts, meningioma, subdural and epidural hematoma), the annual risk of seizures after one postoperative year without seizure becomes less than 2% for the ensuing years. For all higher-risk conditions (low-grade glioma, high-grade glioma, intracranial abscess), a COSY < 2% is never reached, even in patients who have not had a seizure for 1 year postoperatively. Longer-term data (for instance, over 5 years postoperatively) is not available.