Epilepsy after cranioplasty
Among the several cranioplasty complications, epilepsy is a common complication with an incidence of 14.8-33.0% 1) 2).
Antiepileptic drugs can effectively reduce the occurrence of seizures 3).
Seizures are a recognised complication of cranioplasty but its incidence and risk factors in TBI patients are unclear. Accurate prognostication can help direct prophylactic and treatment strategies for seizures. In a systematic review, Spencer et al., aimed to evaluate current literature on these factors. A PROSPERO-registered systematic review was performed in accordance with PRISMA guidelines. Data was synthesised qualitatively and quantitatively in meta-analysis where appropriate. A total of 8 relevant studies were identified, reporting 919 cranioplasty patients. Random-effects meta-analysis reveals a pooled incidence of post-cranioplasty seizures (PCS) of 5.1% (95% CI 2.6-8.2%). Identified risk factors from a single study included increasing age (OR 6.1, p = 0.006), contusion at cranioplasty location (OR 4.8, p = 0.015), and use of monopolar diathermy at cranioplasty (OR 3.5, p = 0.04). There is an association between an extended DC-cranioplasty interval and PCS risk although it did not reach statistical significance (p = 0.062). Predictive factors for PCS are poorly investigated in the TBI population to date. Heterogeneity of included studies preclude meta-analysis of risk factors. Further studies are required to define the true incidence of PCS in TBI and its predictors, and trials are needed to inform management of these patients. 4).
Two hundred and thirty-eight patients who received cranioplasty following craniectomy between January 2012 and December 2014 were included in a study. The risk factors of the patients with early and late post-cranioplasty seizures were compared to those with no post-cranioplasty seizures.
Seizures (73/238, 30.3%) were the most common complication after cranioplasty. Of these 73 patients, 17 (7.1%) had early post-cranioplasty seizures and 56 (23.5%) had late post-cranioplasty seizures. Early post-cranioplasty seizures were related to a longer interval between craniectomy and cranioplasty (P = 0.006), artificial materials (P < 0.001), and patients with late post-craniectomy seizures (P = 0.001). Late post-cranioplasty seizures were related to the presence of neurological deficits (P = 0.042). After stepwise logistic regression analysis, a longer interval between craniectomy and cranioplasty (P = 0.012; OR: 1.004, 95% CI: 1.001-1.007) and late post-craniectomy seizures (P = 0.033; OR: 4.335, 95% CI: 1.127-16.675) were independently associated with early post-cranioplasty seizures.
Delayed cranioplasty procedures and seizures before cranioplasty were significantly associated with early post-cranioplasty seizures. Further studies are warranted to investigate whether early surgery after craniectomy can reduce the risk of early post-cranioplasty seizures 5).
A retrospective study, covering the period between January 2008 and July 2015, compared postcranioplasty seizures (PCS) in postcranioplasty patients. Postcranioplasty seizures risk factors included diabetes mellitus, hypertension, time between DC and cranioplasty, duraplasty material, cranioplasty contusion location, electrocautery method, PCS type, and infection. Multivariate logistic regression analysis was performed and confidence intervals (CIs) were calculated (95% CI).
Of 270 patients, 32 exhibited initial PCS onset postcranioplasty with 11.9% incidence (32/270). Patients fell into immediate (within 24 hours), early (from 1 to 7 days), and late (after 7 days) PCS groups with frequencies of 12, 5, and 15 patients, respectively. Generalized, partial, and mixed seizure types were observed in 13, 13, and 6 patients, respectively. Multivariate logistic regression analysis showed increased risk with increasing age (>50 years). Cranioplasty contusion location, precranioplasty deficits, duraplasty material, and monopolar electrocautery were predictive of PCS onset (P < 0.05). Increased DC to cranioplasty interval increased risk but was not statistically significant (P = 0.062).
Understanding risk factors for PCS will benefit the management of cranioplasty patients 6).