RESUMEN
Tremor is a debilitating symptom that can lead to functional impairment. Pharmacotherapy is often successful, but up to 50% of patients are resistant to medications or cannot tolerate side effects. Thalamotomy to the ventral intermediate nucleus of the thalamus is a surgical intervention for refractory tremor. Thalamotomy surgeries include radiofrequency and incisionless procedures, such as Gamma Knife radiosurgery and magnetic resonance-guided focused ultrasound. Cognitive changes following thalamotomy have been inconsistently reported across studies. We performed a meta-analysis to summarize the impact of unilateral thalamotomy to the ventral intermediate nucleus of the thalamus across multiple cognitive domains. We searched MEDLINE, Embase Classic, Embase and EBM Reviews for relevant studies. Neuropsychological tests were categorized into seven cognitive domains: global cognition, verbal memory, non-verbal memory, executive function, phonemic fluency, semantic fluency and visuospatial processing. We calculated standardized mean differences as Hedges' g and 95% confidence intervals of the change between pre- and postoperative cognitive scores. Pooling of standardized mean differences across studies was performed using random-effects models. Risk of bias across studies and quality of evidence for each cognitive domain were assessed with the National Institute of Health quality assessment tool and the GRADEpro Guideline Development Tool, respectively. Of the 1251 records reviewed, eight studies met inclusion criteria. We included 193 patients with essential tremor, Parkinson's disease, or multiple sclerosis in the meta-analysis. There was a small significant decline in phonemic fluency [standardized mean difference = -0.29, 95% confidence interval: (-0.52, -0.05), P = 0.017] and a trend towards a decline in semantic fluency [standardized mean difference = -0.19, 95% confidence interval: (-0.40, 0.01), P = 0.056]. No postoperative changes were observed in the other cognitive domains (P values >0.14). In secondary analyses, we restricted the analyses to studies using magnetic resonance-guided focused ultrasound given its growing popularity and more precise targeting. In those analyses, there was no evidence of cognitive decline across any domain (P values >0.37). In terms of risk of bias, five studies were rated as 'good' and three studies were rated as 'fair'. According to GRADEpro guidelines, the certainty of the effect for all cognitive domains was low. This study provides evidence that unilateral thalamotomy to the ventral intermediate nucleus of the thalamus is relatively safe from a cognitive standpoint, however, there may be a small decline in verbal fluency. Magnetic resonance-guided focused ultrasound might have a more favourable postoperative cognitive profile compared with other thalamotomy techniques.
RESUMEN
BACKGROUND: Sinking skin flap syndrome (SSFS) is an uncommon complication that can follow decompressive craniectomy. Even less common is the development of SSFS following bone resorption after cranioplasty with exacerbation by a ventriculoperitoneal (VP) shunt. OBSERVATIONS: A 56-year-old male sustained a severe traumatic brain injury and subsequently underwent an emergent decompressive craniectomy. After craniectomy, a cranioplasty was performed, and a VP shunt was placed. The patient returned to the emergency department 5 years later with left-sided hemiplegia and seizures. His clinical presentation was attributed to complete bone flap resorption (BFR) complicated by SSFS likely exacerbated by his VP shunt and the resultant mass effect on the underlying brain parenchyma. The patient underwent surgical intervention via synthetic bone flap replacement. Within 6 days, he recovered to his baseline neurological status. LESSONS: SSFS after complete BFR is a rare complication following cranioplasty. To the authors' knowledge, having a VP shunt in situ to exacerbate the clinical picture has yet to be reported in the literature. In addition to presenting the case, the authors also describe an effective treatment strategy of decompressing the brain and elevating the scalp flap while addressing the redundant tissue, then using a synthetic mesh to reconstruct the calvarial defect while keeping the shunt in situ.
