Brain Shift during Staged Deep Brain Stimulation for Movement Disorders.

INTRODUCTION: Deep brain stimulation (DBS) is a routine neurosurgical procedure utilized to treat various movement disorders including Parkinson's disease (PD), essential tremor (ET), and dystonia. Treatment efficacy is dependent on stereotactic accuracy of lead placement into the deep brain target of interest. However, brain shift attributed to pneumocephalus can introduce unpredictable inaccuracies during DBS lead placement. This study aimed to determine whether intracranial air is associated with brain shift in patients undergoing staged DBS surgery. METHODS: We retrospectively evaluated 46 patients who underwent staged DBS surgery for PD, ET, and dystonia. Due to the staged nature of DBS surgery at our institution, the first electrode placement is used as a concrete fiducial marker for movement in the target location. Postoperative computed tomography (CT) images after the first electrode implantation, as well as preoperative, and postoperative CT images after the second electrode implantation were collected. Images were analyzed in stereotactic targeting software (BrainLab); intracranial air was manually segmented, and electrode shift was measured in the x, y, and z plane, as well as a Euclidian distance on each set of merged CT scans. A Pearson correlation analysis was used to determine the relationship between intracranial air and brain shift, and student's t test was used to compare means between patients with and without radiographic evidence of intracranial air. RESULTS: Thirty-six patients had pneumocephalus after the first electrode implantation, while 35 had pneumocephalus after the second electrode implantation. Accumulation of intracranial air following the first electrode implantation (4.49 ± 6.05 cm3) was significantly correlated with brain shift along the y axis (0.04 ± 0.35 mm; r (34) = 0.36; p = 0.03), as well as the Euclidean distance of deviation (0.57 ± 0.33 mm; r (34) = 0.33; p = 0.05) indicating statistically significant shift on the ipsilateral side. However, there was no significant correlation between intracranial air and brain shift following the second electrode implantation, suggesting contralateral shift is minimal. Furthermore, there was no significant difference in brain shift between patients with and without radiographic evidence of intracranial air following both electrode implantation surgeries. CONCLUSION: Despite observing volumes as high as 22.0 cm3 in patients with radiographic evidence of pneumocephalus, there was no significant difference in brain shift when compared to patients without pneumocephalus. Furthermore, the mean magnitude of brain shift was <1.0 mm regardless of whether pneumocephalus was presenting, suggesting that intracranial air accumulation may not produce clinical significant brain shift in our patients.

Corrigendum: The role of the piriform cortex in temporal lobe epilepsy: A current literature review.

[This corrects the article DOI: 10.3389/fneur.2022.1042887.].

The role of the piriform cortex in temporal lobe epilepsy: A current literature review.

Temporal lobe epilepsy is the most common form of focal epilepsy and can have various detrimental consequences within many neurologic domains. Recent evidence suggests that the piriform cortex may also be implicated in seizure physiology. The piriform cortex is a primary component of the olfactory network and is located at the junction of the frontal and temporal lobes, wrapping around the entorhinal sulcus. Similar to the hippocampus, it is a tri-layered allocortical structure, with connections to many adjacent regions including the orbitofrontal cortex, amygdala, peri- and entorhinal cortices, and insula. Both animal and human studies have implicated the piriform cortex as a critical node in the temporal lobe epilepsy network. It has additionally been shown that resection of greater than half of the piriform cortex may significantly increase the odds of achieving seizure freedom. Laser interstitial thermal therapy has also been shown to be an effective treatment strategy with recent evidence hinting that ablation of the piriform cortex may be important for seizure control as well. We propose that sampling piriform cortex in intracranial stereoelectroencephalography (sEEG) procedures with the use of a temporal pole or amygdalar electrode would be beneficial for further understanding the role of the piriform cortex in temporal lobe epilepsy.

Transient cardiac asystole during vagus nerve stimulator implantation: A case report.

Background: Vagal nerve stimulation (VNS) is a Food and Drug Administration approved therapy for seizures with a suggested mechanism of action consisting of cortical desynchronization, facilitated through broad release of inhibitory neurotransmitters in the cortex and brainstem. The vagus nerve contains visceral afferents that transmit sensory signals centrally, from locations that include the heart and the aorta. Although the vagus nerve serves a role in cardiac function, electrical stimulation with VNS has rarely resulted in adverse cardiac events. Here, we report a case of a cardiac event during left-sided VNS implantation. Case Description: A 22-year-old male with an 8-year history of absence seizures and a 3-year history of medically refractory generalized tonic-clonic seizure was planned for surgical implantation of a VNS device. In the operating room, the patient underwent left-sided VNS implantation. An initial impedance check was performed with subsequent wound irrigation; following a few seconds of irrigation, a 5 s complete cardiac pause was noted. A repeated impedance check, which included turning on the stimulation, did not replicate the cardiac pause. No further pauses or cardiac events were noted and the case continued to completion without issue. The patient was later activated without any further complications. Conclusion: This report describes the initiation of a cardiac event, unlikely resulting from VNS, but instead time linked to intraoperative irrigation directly on the vagus nerve.

Clinical Indicators of Pediatric Shunt Malfunction: A Population-Based Study From the Nationwide Emergency Department Sample.

OBJECTIVES: The majority of the previous literature on clinical predictors of shunt malfunction is from the neurosurgical data, looking at the symptoms of patients who had surgery. Because common childhood illnesses are filtered from these samples, the prevalence of shunt malfunction is markedly higher than it would be for the pediatrician's office or emergency department (ED). Clinical predictive values obtained from a representative population can better inform clinical judgment in these environments. METHODS: A retrospective analysis of the Nationwide Emergency Department Sample (2006-2015) was performed. International Classification of Diseases, Ninth Revision, Clinical Modification Diagnosis/Procedure Codes were used to identify pediatric (≤20 years of age) ED visits with the presence of a cerebrospinal fluid (CSF) shunt (V45.2). Shunt malfunction was defined as any condition resulting in surgical revision (02.41, 02.42, 02.43). Multivariable logistic regression was used to examine the associations between shunt malfunction, demographic factors, and clinical presentation. RESULTS: There were 74,552 observations for ED visits by pediatric patients with a CSF shunt between 2006 and 2015, of which 12.8% (9,560) required shunt revision. Positive predictive values for clinical indicators were reported along with the results of multivariable logistic regression. CONCLUSIONS: We identified peritonitis, papilledema, and oculomotor palsies as the strongest clinical indicators for shunt malfunction in pediatric ED visits with a CSF shunt. We found that patients presenting with headache, nausea/vomiting, convulsions, or fever were more likely to have an etiology other than shunt malfunction. Thus, after an appropriate shunt evaluation, other sources of symptoms should be investigated.

Hysteroscopic sterilization in an immunosuppressed patient.

Essure sterilization produces a local benign tissue response resulting in bilateral occlusion of the fallopian tubes 3 months after insertion. There is a precautionary warning about performing this procedure on immunosuppressed patients. We present a case of successful bilateral tubal occlusion with Essure in a patient with a history of kidney transplantation and receiving immunosuppressive medications.