Risk factors and significance of post-operative edema in Parkinson Disease patients submitted to deep brain stimulation. A ten-year case series.

BACKGROUND: Peri-electrode edema after deep brain stimulation (DBS) surgery for Parkinson Disease (PD) has been reported in up to 100% of cases. The clinical significance of this finding is unclear, with most papers suggesting a benign course. The risk factors are also poorly defined. We aimed at defining the incidence rate, the clinical significance and the predictive factors of peri-electrode edema in patients undergoing DBS for PD. METHODS: We reviewed data of 119 patients treated with frameless stereotactic DBS for PD between 2012 and 2022 at our Institution. A mixed-technique targeting was adopted. Awake surgery was used in 64.7% cases; in most cases, microelectrode recording (MER) was adopted. The target was the subthalamic nucleus (STN) in 91.2% cases. RESULTS: Ninety patients were included. Postoperative edema related to lead placement was noticed in 40% patients after a median time of 2 days since surgery; in 88.9% of these cases, it was limited to subcortical white matter. Symptomatic edema was registered only in one case (1.1%), confirming previous reports on the benign clinical course. The only independent predictive factor for edema onset was asleep surgery (p = 0.0451). Notably, the use of directional electrodes was not associated with an increased risk of edema at multivariable analysis. Clinical parameters including age, and timing of CT scanning, did not affect edema onset. CONCLUSIONS: We confirmed the very low rate of symptomatic edema in DBS for PD. When feasible, awake DBS using MER is the ideal technique to reduce the risk of radiologic postoperative edema.

Intraoperative microelectrode recording during asleep deep brain stimulation of subthalamic nucleus for Parkinson Disease. A case series with systematic review of the literature.

The use of microelectrode recording (MER) during deep brain stimulation (DBS) for Parkinson Disease is controversial. Furthermore, in asleep DBS anesthesia can impair the ability to record single-cell electric activity.The purpose of this study was to describe our surgical and anesthesiologic protocol for MER assessment during asleep subthalamic nucleus (STN) DBS and to put our findings in the context of a systematic review of the literature. Sixty-three STN electrodes were implanted in 32 patients under general anesthesia. A frameless technique using O-Arm scanning was adopted in all cases. Total intravenous anesthesia, monitored with bispectral index, was administered using a target controlled infusion of both propofol and remifentanil. A systematic review of the literature with metanalysis on MER in asleep vs awake STN DBS for Parkinson Disease was performed. In our series, MER could be reliably recorded in all cases, impacting profoundly on electrode positioning: the final position was located within 2 mm from the planned target only in 42.9% cases. Depth modification > 2 mm was necessary in 21 cases (33.3%), while in 15 cases (23.8%) a different track was used. At 1-year follow-up we observed a significant reduction in LEDD, UPDRS Part III score off-medications, and UPDRS Part III score on medications, as compared to baseline. The systematic review of the literature yielded 23 papers; adding the cases here reported, overall 1258 asleep DBS cases using MER are described. This technique was safe and effective: metanalysis showed similar, if not better, outcome of asleep vs awake patients operated using MER. MER are a useful and reliable tool during asleep STN DBS, leading to a fine tuning of electrode position in the majority of cases. Collaboration between neurosurgeon, neurophysiologist and neuroanesthesiologist is crucial, since slight modifications of sedation level can impact profoundly on MER reliability.

Reliability of intraoperative visual evoked potentials (iVEPs) in monitoring visual function during endoscopic transsphenoidal surgery.

OBJECTIVE: To refine a reliable and reproducible intraoperative visual evoked potentials (iVEPs) monitoring protocol during endoscopic transsphenoidal surgery. To assess the reliability of baseline iVEPs in predicting preoperative visual status and perioperative iVEP variation in predicting postoperative visual outcome. METHODS: Sixty-four patients harboring tumors of the pituitary region were included. All patients underwent endoscopic endonasal approach (EEA) with iVEPs monitoring, using a totally intravenous anesthetic protocol. Ophthalmological evaluation included visual acuity and visual field studies. RESULTS: Preoperatively, visual acuity was reduced in 86% and visual field in 76.5% of cases. Baseline iVEPs amplitude was significantly correlated with preoperative visual acuity and visual field (p = 0.001 and p = 0.0004, respectively), confirming the reliability of the neurophysiological/anesthetic protocol implemented. Importantly, perioperatively the variation in iVEPs amplitude was significantly correlated with the changes in visual acuity (p < 0.0001) and visual field (p = 0.0013). ROC analysis confirmed that iVEPs are an accurate predictor of perioperiative visual acuity improvement, with a 100% positive predictive value in patients with preoperative vision loss. CONCLUSIONS: iVEPs during EEA is highly reliable in describing preoperative visual function and can accurately predict postoperative vision improvement. SIGNIFICANCE: iVEPs represent a promising resource for carrying out a more effective and safe endoscopic transsphenoidal surgery.

Electrocardiographic-Guided Technique for Placement of Ventriculoatrial Shunts: A Valid and Cost-Effective Technical Simplification.

BACKGROUND: Ventriculoatrial (VA) shunt is a routine technique for the treatment of hydrocephalus. The correct position at the superior vena cava-right atrium junction is generally assessed by radiography. We present the first experience of an alternative, nonradiographic technique to assess the distal end of the VA shunts through an electrocardiographic (EKG) method. The technique has developed from the large experience of central venous catheters (CVC) worldwide; the EKG-guided method is a common and validated alternative to standard radiologic control of the location of the tip of any CVC. METHODS: Five consecutive patients underwent VA shunt with venous catheter positioned with the EKG-guided technique. The position of the catheter tip was verified by standard chest radiography. RESULTS: Four men and 1 woman (mean age, 45.4 years) underwent VA shunt for hydrocephalus with the EKG-guided technique. The side of internal jugular vein puncture was the right side in 4 cases and the left side in 1 case. As confirmed by radiography, all VA shunt tips were located within the correct range. There was no radiologic evidence of procedure-related complication or catheters that had to be replaced. CONCLUSIONS: The EKG-guided technique for VA shunts is as accurate as fluoroscopy, but simpler, more readily available, less expensive, safer, and more cost effective. It reduces the need of radiography and radiologic exposition for both patients and operators. The EKG method may be a valid and cost-effective alternative to standard radiologic control in VA shunts, as for any central venous access device, and could become the preferential method for confirming tip position during VA shunt surgery.

Italian COnsensus in Neuroradiological Anesthesia (ICONA).

Anesthetic management of patients undergoing endovascular procedures for treating intracranial aneurysms or cerebrovascular malformations must consider a number of specific challenges, in addition to those associated with anesthesia for other specialties. In addition to maintenance of physiological stability, manipulation of systemic and cerebral hemodynamic parameters may be required to treat any sudden unexpected catastrophic neurological events. A multidisciplinary group including neuro- and pediatric anesthesiologists, interventional neuroradiologists, neurosurgeons, and a clinical methodologist contributed to this document. This consensus working group from 21 Italian institutions identified open questions regarding the best practices for management of anesthesia during endovascular neuroradiological procedures for intracranial aneurysms and cerebrovascular malformations, and addressed these by formulating practical consensus statements. At the first meeting in November 2015, nine key areas were identified regarding choice of anesthetic, patient monitoring, hemodynamic targets, postoperative care, and the management of neuromuscular blockade, anticoagulant and/or antiplatelet therapy, and special considerations for pediatric patients. Nine subgroups were established and a medical librarian performed literature searches in the Cochrane and MEDLINE/PubMed databases for each group. Groups drafted literature summaries and provisional responses in the form of candidate consensus statements based on evidence, when possible, and clinical experience, when this was lacking. Final wording was agreed at a meeting in April 2016 and where possible evidence was graded using United States Preventive Services Task Force criteria. Consensus (defined as >90% agreement) was based on evidence, clinical experience, clinician preference, feasibility in the Italian healthcare system, and cost/benefit considerations.