Subthalamic deep brain stimulation after anesthetic inhalation in Parkinson disease: a preliminary study

Incidence of complications associated with deep brain stimulation surgery in patients with Parkinson's disease: An 8-year retrospective study

Background

Various complications occur in patients undergoing deep brain stimulation (DBS) surgery. The objective of this study was to determine the incidence of complications in patients with Parkinson's disease who underwent DBS surgery and identify the risk factors, especially anesthetic factors.

Methods

A retrospective cohort study was performed between May 2015 and December 2022. Based on a review of medical charts, patients aged 18 years or older who underwent DBS surgery at a tertiary neurological center in Thailand were recruited. Univariate analysis using the Chi-square test or Fisher's exact test was performed to compare patients with and without complications. Multivariate logistic regression analysis was performed to identify the predictive factors for complications.

Results

The study included 46 patients. The most common complication during DBS electrode placement was hypertension (30/46, 65.2%), and 19 patients (41.3%) who developed hypertension did not receive antihypertensive treatment. The most common complication during battery placement was clinical hypotension (14/46, 30.4%). The most common postoperative complication was delirium (6/46, 13.0%). In the multivariate analysis, no significant independent risk factors for overall complications after DBS surgery were identified.

Conclusions

Hypertension during DBS electrode insertion was the most common perioperative complication. Hemodynamic instability is preventable and manageable, and vigilant and prompt treatment should be provided during DBS surgery.

STN-DBS electrode placement accuracy and motor improvement in Parkinson's disease: systematic review and individual patient meta-analysis

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective neurosurgical treatment for Parkinson's disease. Surgical accuracy is a critical determinant to achieve an adequate DBS effect on motor performance. A two-millimetre surgical accuracy is commonly accepted, but scientific evidence is lacking. A systematic review and meta-analysis of study-level and individual patient data (IPD) was performed by a comprehensive search in MEDLINE, EMBASE and Cochrane Library. Primary outcome measures were (1) radial error between the implanted electrode and target; (2) DBS motor improvement on the Unified Parkinson's Disease Rating Scale part III (motor examination). On a study level, meta-regression analysis was performed. Also, publication bias was assessed. For IPD meta-analysis, a linear mixed effects model was used. Forty studies (1391 patients) were included, reporting radial errors of 0.45-1.86 mm. Errors within this range did not significantly influence the DBS effect on motor improvement. Additional IPD analysis (206 patients) revealed that a mean radial error of 1.13±0.75 mm did not significantly change the extent of DBS motor improvement. Our meta-analysis showed a huge publication bias on accuracy data in DBS. Therefore, the current literature does not provide an unequivocal upper threshold for acceptable accuracy of STN-DBS surgery. Based on the current literature, DBS-electrodes placed within a 2 mm range of the intended target do not have to be repositioned to enhance motor improvement after STN-DBS for Parkinson's disease. However, an indisputable upper cut-off value for surgical accuracy remains to be established. PROSPERO registration number is CRD42018089539.

The efficacy and safety of asleep and awake subthalamic deep brain stimulation for Parkinson's disease patients: A 1-year follow-up

Introduction

Traditional DBS is usually conducted under local anesthesia (LA) which is intolerable to some patients, DBS under general anesthesia (GA) was opted to extended surgical indication. This study aimed to compare the efficacy and safety of bilateral subthalamic deep brain stimulation (STN-DBS) for Parkinson's disease (PD) under asleep and awake anesthesia state in 1-year postoperative follow-up.

Methods

Twenty-one PD patients were assigned to asleep group and 25 patients to awake group. Patients received bilateral STN-DBS under different anesthesia state. The PD participants were interviewed and assessed preoperatively and at 1-year postoperative follow-up.

Results

At 1-year follow-up, compared surgical coordinate in two groups, the left-side Y of asleep group showed more posterior than awake group (Y was-2.39 ± 0.23 in asleep group, -1.46 ± 0.22 in awake group, p = 0.007). Compared with preoperative OFF MED state, MDS-UPDRS III scores in OFF MED/OFF STIM state remained unchanged, while in OFF MED/ON STIM state were significantly improved in awake and asleep groups, yet without significant difference. Compared with preoperative ON MED state, MDS-UPDRS III scores in ON MED/OFF STIM, and ON MED/ON STIM state remained unchanged in both groups. In non-motor outcomes, PSQI, HAMD, and HAMA score significantly improved in asleep group compared to awake group at 1-year follow-up (PSQI, HAMD, and HAMA score in 1-year follow-up were 9.81 ± 4.43; 10.00 ± 5.80; 5.71 ± 4.75 in awake group, 6.64 ± 4.14; 5.32 ± 3.78; 3.76 ± 3.87 in asleep group, p = 0.009; 0.008; 0.015, respectively), while there was no significant difference in PDQ-39, NMSS, ESS, PDSS score, and cognitive function. Anesthesia methods was significantly associated with improvement of HAMA and HAMD score (p = 0.029; 0.002, respectively). No difference in LEDD, stimulation parameters and adverse events was observed between two groups.

Discussion

Asleep STN-DBS may be considered a good alternative method for PD patients. It is largely consistent with awake STN-DBS in motor symptoms and safety. Yet, it showed higher improvement in terms of mood and sleep compared to awake group at 1-year follow-up.

Nomogram for Prediction of Postoperative Delirium after Deep Brain Stimulation of Subthalamic Nucleus in Parkinson’s Disease under General Anesthesia

Introduction. Postoperative delirium can increase cognitive impairment and mortality in patients with Parkinson’s disease. The purpose of this study was to develop and internally validate a clinical prediction model of delirium after deep brain stimulation of the subthalamic nucleus in Parkinson’s disease under general anesthesia. Methods. We conducted a retrospective observational cohort study on the data of 240 patients with Parkinson’s disease who underwent deep brain stimulation of the subthalamic nucleus under general anesthesia. Demographic characteristics, clinical evaluation, imaging data, laboratory data, and surgical anesthesia information were collected. Multivariate logistic regression was used to develop the prediction model for postoperative delirium. Results. A total of 159 patients were included in the cohort, of which 38 (23.90%) had postoperative delirium. Smoking (OR 4.51, 95% CI 1.56–13.02, $p<0.01$ ) was the most important risk factor; other independent predictors were orthostatic hypotension (OR 3.42, 95% CI 0.90–13.06, $p=0.07$ ), inhibitors of type-B monoamine oxidase (OR 3.07, 95% CI 1.17–8.04, $p=0.02$ ), preoperative MRI with silent brain ischemia or infarction (OR 2.36, 95% CI 0.90–6.14, $p=0.08$ ), Hamilton anxiety scale score (OR 2.12, 95% CI 1.28–3.50, $p<0.01$ ), and apolipoprotein E level in plasma (OR 1.48, 95% CI 0.95–2.29, $p=0.08$ ). The area under the receiver operating characteristic curve (AUC) was 0.76 (95% CI 0.66–0.86). A nomogram was established and showed good calibration and clinical predictive capacity. After bootstrap for internal verification, the AUC was 0.74 (95% CI 0.66–0.83). Conclusion. This study provides evidence for the independent inducing factors of delirium after deep brain stimulation of the subthalamic nucleus in Parkinson’s disease under general anesthesia. By predicting the development of delirium, our model may identify high-risk groups that can benefit from early or preventive intervention.

Effect of Anesthesia on Microelectrode Recordings During Deep Brain Stimulation Surgery: A Narrative Review

Deep brain stimulation (DBS) is an effective surgical treatment for patients with various neurological and psychiatric disorders. Clinical improvements rely on careful patient selection and accurate electrode placement. A common method for target localization is intraoperative microelectrode recording (MER). To facilitate MER, DBS surgery is traditionally performed under local or regional anesthesia. However, sedation or general anesthesia is sometimes needed for patients who are unable to tolerate the procedure fully awake because of severe motor symptoms, psychological distress, pain, or other forms of discomfort. The effect of anesthetic drugs on MER is controversial but likely depends on the type and dose of a particular anesthetic agent, underlying disease, and surgical target. In this narrative review, we provide an overview of the current literature on the anesthetic drugs most often used for sedation and anesthesia during DBS surgery, with a focus on their effects on MERs.

Optimized Propofol Anesthesia Increases Power of Subthalamic Neuronal Activity in Patients with Parkinson's Disease Undergoing Deep Brain Stimulation

Introduction

Propofol is a general anesthetic option for deep brain stimulation (DBS) of the subthalamic nucleus (STN) of patients with Parkinson's disease (PD). However, its effects on STN activity and neuropsychological outcomes are controversial. The optimal propofol anesthesia for asleep DBS is unknown. This study investigated the safety and effectiveness of an optimized propofol anesthesia regimen in asleep DBS.

Methods

This retrospective study enrolled 68 PD patients undergoing bilateral STN-DBS surgery. All patients received local scalp anesthesia, with (asleep group, n = 35) or without (awake group, n = 33) propofol-remifentanil general anesthesia by target-controlled infusion under electroencephalogram monitoring. The primary outcome was subthalamic neuronal spiking characterization during microelectrode recording. The secondary outcomes were clinical outcomes including motor, cognition, mind, sleep, and quality of life at 6 months.

Results

Significantly increased delta and theta power were obtained under propofol anesthesia (awake vs. asleep group, mean ± standard deviation; delta: 31.97 ± 9.87 vs. 39.77 ± 10.56, p < 0.01; theta: 21.09 ± 5.55 vs. 24.82 ± 6.63, p = 0.01). After excluding the influence of confounding factors of age and preoperative motor scores, there was a statistically significant influence on the delta, theta, and alpha power of STN neuronal activity under different anesthesia regimens (delta: β = 2.64, p < 0.01; theta: β = 2.11, p < 0.01; alpha: β = 1.42, p = 0.01). There were no differences in modified burst index, firing rate, tract numbers of microelectrode recording, and other clinical outcomes between the two groups.

Conclusion

Optimized propofol anesthesia enhanced the delta, theta, and alpha power in STN compared with the awake technique and likely contributed to target recognition under propofol anesthesia. These results demonstrate that propofol is suitable, but needs to be optimized, for asleep STN-DBS.

Trial Registration

Chinese Clinical Trial Registry Identification number: ChiCTR2100045942. Registered 29 April 2021–Retrospectively registered

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-021-00259-y.

Bilateral Subthalamic Nucleus Deep Brain Stimulation under General Anesthesia: Literature Review and Single Center Experience

Bilateral subthalamic nucleus (STN) Deep brain stimulation (DBS) is a well-established treatment in patients with Parkinson's disease (PD). Traditionally, STN DBS for PD is performed by using microelectrode recording (MER) and/or intraoperative macrostimulation under local anesthesia (LA). However, many patients cannot tolerate the long operation time under LA without medication. In addition, it cannot be even be performed on PD patients with poor physical and neurological condition. Recently, it has been reported that STN DBS under general anesthesia (GA) can be successfully performed due to the feasible MER under GA, as well as the technical advancement in direct targeting and intraoperative imaging. The authors reviewed the previously published literature on STN DBS under GA using intraoperative imaging and MER, focused on discussing the technique, clinical outcome, and the complication, as well as introducing our single-center experience. Based on the reports of previously published studies and ours, GA did not interfere with the MER signal from STN. STN DBS under GA without intraoperative stimulation shows similar or better clinical outcome without any additional complication compared to STN DBS under LA. Long-term follow-up with a large number of the patients would be necessary to validate the safety and efficacy of STN DBS under GA.

Can Pallidal Deep Brain Stimulation Rescue Borderline Dystonia? Possible Coexistence of Functional (Psychogenic) and Organic Components

The diagnosis and treatment of functional movement disorders are challenging for clinicians who manage patients with movement disorders. The borderline between functional and organic dystonia is often ambiguous. Patients with functional dystonia are poor responders to pallidal deep brain stimulation (DBS) and are not good candidates for DBS surgery. Thus, if patients with medically refractory dystonia have functional features, they are usually left untreated with DBS surgery. In order to investigate the outcome of functional dystonia in response to pallidal DBS surgery, we retrospectively included five patients with this condition. Their dystonia was diagnosed as organic by dystonia specialists and also as functional according to the Fahn and Williams criteria or the Gupta and Lang Proposed Revisions. Microelectrode recordings in the globus pallidus internus of all patients showed a cell-firing pattern of bursting with interburst intervals, which is considered typical of organic dystonia. Although their clinical course after DBS surgery was incongruent to organic dystonia, the outcome was good. Our results question the possibility to clearly differentiate functional dystonia from organic dystonia. We hypothesized that functional dystonia can coexist with organic dystonia, and that medically intractable dystonia with combined functional and organic features can be successfully treated by DBS surgery.

Sevoflurane and Parkinson’s Disease

Background

General anesthetics-induced changes of electrical oscillations in the basal ganglia may render the identification of the stimulation targets difficult. The authors hypothesized that while sevoflurane anesthesia entrains coherent lower frequency oscillations, it does not affect the identification of the subthalamic nucleus and clinical outcome.

Methods

A cohort of 19 patients with Parkinson’s disease with comparable disability underwent placement of electrodes under either sevoflurane general anesthesia (n = 10) or local anesthesia (n = 9). Microelectrode recordings during targeting were compared for neuronal spiking characteristics and oscillatory dynamics. Clinical outcomes were compared at 5-yr follow-up.

Results

Under sevoflurane anesthesia, subbeta frequency oscillations predominated (general vs. local anesthesia, mean ± SD; delta: 13 ± 7.3% vs. 7.8 ± 4.8%; theta: 8.4 ± 4.1% vs. 3.9 ± 1.6%; alpha: 8.1 ± 4.1% vs. 4.8 ± 1.5%; all P &lt; 0.001). In addition, distinct dorsolateral beta and ventromedial gamma oscillations were detected in the subthalamic nucleus solely in awake surgery (mean ± SD; dorsal vs. ventral beta band power: 20.5 ± 6.6% vs. 15.4 ± 4.3%; P &lt; 0.001). Firing properties of subthalamic neurons did not show significant difference between groups. Clinical outcomes with regard to improvement in motor and psychiatric symptoms and adverse effects were comparable for both groups. Tract numbers of microelectrode recording, active contact coordinates, and stimulation parameters were also equivalent.

Conclusions

Sevoflurane general anesthesia decreased beta-frequency oscillations by inducing coherent lower frequency oscillations, comparable to the pattern seen in the scalp electroencephalogram. Nevertheless, sevoflurane-induced changes in electrical activity patterns did not reduce electrode placement accuracy and clinical effect. These observations suggest that microelectrode-guided deep brain stimulation under sevoflurane anesthesia is a feasible clinical option.

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Five-Year Clinical Outcomes of Local versus General Anesthesia Deep Brain Stimulation for Parkinson's Disease

Background

Studies comparing long-term outcomes between general anesthesia (GA) and local anesthesia (LA) for STN-DBS in Parkinson's disease (PD) are lacking. Whether patients who received STN-DBS in GA could get the same benefit without compromising electrophysiological recording is debated.

Methods

We compared five-year outcomes for different anesthetic methods (GA vs LA) during STN-DBS for PD. Thirty-six consecutive PD patients with similar preoperative characteristics, including age, disease duration, and severity, underwent the same surgical procedures except the GA (n=22) group with inhalational anesthesia and LA (n=14) with local anesthesia during microelectrode recording and intraoperative macrostimulation test. Surgical outcome evaluations included Unified Parkinson's Disease Rating Scale (UPDRS), Mini-Mental Status Examinations, and the Beck Depression Inventory. Stimulation parameters and coordinates of STN targeting were also collected.

Results

Both groups attained similar benefits in UPDRS part III from STN-DBS (GA 43.2 ± 14.1% vs. LA 46.8 ± 13.8% decrease, p=0.45; DBS on/Med off vs. DBS off/Med off) and no difference in reduction of levodopa equivalent doses (GA 47.56 ± 18.98% vs. LA 51.37 ± 31.73%, p=0.51) at the five-year follow-up. In terms of amplitude, frequency, and pulse width, the stimulation parameters used for DBS were comparable, and the coordinates of preoperative targeting and postoperative electrode tip were similar between two groups. There was no difference in STN recording length as well. Significantly less number of MER tracts in GA was found (p=0.04). Adverse effects were similar in both groups.

Conclusions

Our study confirmed that STN localization with microelectrode recording and patient comfort could be achieved based on equal effectiveness and safety of STN-DBS under GA compared with LA.

Passive limb movement test facilitates subthalamic deep brain stimulation under general anesthesia without influencing awareness

Objectives:

We have shown that neuronal activity in the subthalamic nucleus (STN) in patients with Parkinson's disease can be accurately recorded during deep brain stimulation (DBS) with general anesthesia (GA). However, a vigorous passive range of motion (PROM) test might exert awakening effects on patients who are lightly anesthetized. We will explore the effects of PROM on the heart rate (HR) and mean arterial pressure (MAP) during microelectrode recording (MER) and confirm whether it facilitates identifying the sensory motor portion of the STN under GA.

Materials and Methods:

3T magnetic resonance image targeting of the STN was done to guide MER during frame-based stereotactic procedures for DBS. Regular induction and endotracheal intubation for GA were performed and then maintained with a volatile anesthetic agent and muscle relaxant only. The depth of anesthesia was monitored by the bispectral index (BIS).

Results:

A total of ten patients were enrolled in this study. Their mean age was 48.5 ± 10.8 years old with a disease duration 8.6 ± 2.4 years at the time of surgery. During MER, PROM significantly decreased recording tract numbers and still reached the STN at a recorded length at 5.5 ± 0.8 mm. Compared with baseline, PROM increased HR by a mean 0.5 beats/min and MAP by a mean 1.4 mmHg (P = 0.1178 and 0.0525). The change in BIS was −0.7 (P = 0.4941), and the mean alveolar concentration of the anesthetic agent changed little throughout surgery.

Conclusions:

PROM was effective in triggering and magnifying neuronal firing signal without influencing patient awareness during MER for STN-DBS under GA.

Propofol Anesthesia Precludes LFP-Based Functional Mapping of Pallidum during DBS Implantation

BACKGROUND/AIMS

There are reports that microelectrode recording (MER) can be performed under certain anesthetized conditions for functional confirmation of the optimal deep brain stimulation (DBS) target. However, it is generally accepted that anesthesia affects MER. Due to a potential role of local field potentials (LFPs) in DBS functional mapping, we characterized the effect of propofol on globus pallidus interna (GPi) and externa (GPe) LFPs in Parkinson disease (PD) patients.

METHODS

We collected LFPs in 12 awake and anesthetized PD patients undergoing DBS implantation. Spectral power of β (13-35 Hz) and high-frequency oscillations (HFOs: 200-300 Hz) was compared across the pallidum.

RESULTS

Propofol suppressed GPi power by > 20 Hz while increasing power at lower frequencies. A similar power shift was observed in GPe; however, power in the high β range (20-35 Hz) increased with propofol. Before anesthesia both β and HFO activity were significantly greater at the GPi (χ2 = 20.63 and χ2 = 48.81, p < 0.0001). However, during anesthesia, we found no significant difference across the pallidum (χ2 = 0.47, p = 0.79, and χ2 = 4.11, p = 0.12).

CONCLUSION

GPi and GPe are distinguishable using LFP spectral profiles in the awake condition. Propofol obliterates this spectral differentiation. Therefore, LFP spectra cannot be relied upon in the propofol-anesthetized state for functional mapping during DBS implantation.

Awake versus asleep deep brain stimulation for Parkinson's disease: a critical comparison and meta-analysis

OBJECTIVE

No definitive comparative studies of the efficacy of 'awake' deep brain stimulation (DBS) for Parkinson's disease (PD) under local or general anaesthesia exist, and there remains significant debate within the field regarding differences in outcomes between these two techniques.

METHODS

We conducted a literature review and meta-analysis of all published DBS for PD studies (n=2563) on PubMed from January 2004 to November 2015. Inclusion criteria included patient number >15, report of precision and/or clinical outcomes data, and at least 6 months of follow-up. There were 145 studies, 16 of which were under general anaesthesia. Data were pooled using an inverse-variance weighted, random effects meta-analytic model for observational data.

RESULTS

There was no significant difference in mean target error between local and general anaesthesia, but there was a significantly less mean number of DBS lead passes with general anaesthesia (p=0.006). There were also significant decreases in DBS complications, with fewer intracerebral haemorrhages and infections with general anaesthesia (p<0.001). There were no significant differences in Unified Parkinson's Disease Rating Scale (UPDRS) Section II scores off medication, UPDRS III scores off and on medication or levodopa equivalent doses between the two techniques. Awake DBS cohorts had a significantly greater decrease in treatment-related side effects as measured by the UPDRS IV off medication score (78.4% awake vs 59.7% asleep, p=0.022).

CONCLUSIONS

Our meta-analysis demonstrates that while DBS under general anaesthesia may lead to lower complication rates overall, awake DBS may lead to less treatment-induced side effects. Nevertheless, there were no significant differences in clinical motor outcomes between the two techniques. Thus, DBS under general anaesthesia can be considered at experienced centres in patients who are not candidates for traditional awake DBS or prefer the asleep alternative.

Comparison of Awake vs. Asleep Surgery for Subthalamic Deep Brain Stimulation in Parkinson's Disease

BACKGROUND

Deep brain stimulation (DBS) surgery for Parkinson's disease (PD) is usually performed as awake surgery allowing sufficient intraoperative testing. Recently, outcomes after asleep surgery have been assumed comparable. However, direct comparisons between awake and asleep surgery are scarce.

OBJECTIVE

To investigate the difference between awake and asleep surgery comparing motor and nonmotor outcome after subthalamic nucleus (STN)-DBS in a large single center PD population.

METHODS

Ninety-six patients were retrospectively matched pairwise (48 asleep and 48 awake) and compared regarding improvement of Unified PD Rating Scale Motor Score (UPDRS-III), cognitive function, Levodopa-equivalent-daily-dose (LEDD), stimulation amplitudes, side effects, surgery duration, and complication rates. Routine testing took place at three months and one year postoperatively.

RESULTS

Chronic DBS effects (UPDRS-III without medication and with stimulation on [OFF/ON]) significantly improved UPDRS-III only after awake surgery at three months and in both groups one year postoperatively. Acute effects (percentage UPDRS-III reduction after activation of stimulation) were also significantly better after awake surgery at three months but not at one year compared to asleep surgery. UPDRS-III subitems "freezing" and "speech" were significantly worse after asleep surgery at three months and one year, respectively. LEDD was significantly lower after awake surgery only one week postoperatively. The other measures did not differ between groups.

CONCLUSIONS

Overall motor function improved faster in the awake surgery group, but the difference ceased after one year. However, axial subitems were worse in the asleep surgery group suggesting that worsening of axial symptoms was risked improving overall motor function. Awake surgery still seems advantageous for STN-DBS in PD, although asleep surgery may be considered with lower threshold in patients not suitable for awake surgery.

Decreased Power but Preserved Bursting Features of Subthalamic Neuronal Signals in Advanced Parkinson's Patients under Controlled Desflurane Inhalation Anesthesia

Deep brain stimulation (DBS) surgery of the subthalamic nucleus (STN) under general anesthesia (GA) had been used in Parkinson's disease (PD) patients who are unable tolerate awake surgery. The effect of anesthetics on intraoperative microelectrode recording (MER) remains unclear. Understanding the effect of anesthetics on MER is important in performing STN DBS surgery with general anesthesia. In this study, we retrospectively performed qualitive and quantitative analysis of STN MER in PD patients received STN DBS with controlled desflurane anesthesia or LA and compared their clinical outcome. From January 2005 to March 2006, 19 consecutive PD patients received bilateral STN DBS surgery in Hualien Tzu-Chi hospital under either desflurane GA (n = 10) or LA (n = 9). We used spike analysis (frequency and modified burst index [MBI]) and the Hilbert transform to obtain signal power measurements for background and spikes, and compared the characterizations of intraoperative microelectrode signals between the two groups. Additionally, STN firing pattern characteristics were determined using a combined approach based on the autocorrelogram and power spectral analysis, which was employed to investigate differences in the oscillatory activities between the groups. Clinical outcomes were assessed using the Unified Parkinson's Disease Rating Scale (UPDRS) before and after surgery. The results revealed burst firing was observed in both groups. The firing frequencies were greater in the LA group and MBI was comparable in both groups. Both the background and spikes were of significantly greater power in the LA group. The power spectra of the autocorrelograms were significantly higher in the GA group between 4 and 8 Hz. Clinical outcomes based on the UPDRS were comparable in both groups before and after DBS surgery. Under controlled light desflurane GA, burst features of the neuronal firing patterns are preserved in the STN, but power is reduced. Enhanced low-frequency (4–8 Hz) oscillations in the MERs for the GA group could be a characteristic signature of desflurane's effect on neurons in the STN.

Comparison of General and Local Anesthesia for Deep Brain Stimulator Insertion: A Systematic Review

BACKGROUND

Subthalamic nucleus deep brain stimulation (STN-DBS) has become a standard treatment for many patients with Parkinson's disease (PD). The reported clinical outcome measures for procedures done under general anesthesia (GA) compared to traditional local anesthetic (LA) technique are quite heterogeneous and difficult to compare. The aim of this systematic review and metaanalysis was to determine whether the clinical outcome after STN-DBS insertion under GA is comparable to that under LA in patients with Parkinson's disease.

METHODS

The databases of Medline Embase, Cochrane library and Pubmed were searched for eligible studies (human trials, English language, published between 1946 and January of 2016). The primary outcome of this study was to assess the postoperative improvement in the symptoms, evaluated using either Unified Parkinson's Disease Rating Scale (UPDRS) scores or levodopa equivalent dosage (LEDD) requirement.

RESULTS

The literature searches yielded 395 citations and six retrospective cohort studies with a sample size of 455 (194 in GA and 261 in LA) were included in the analysis. Regarding the clinical outcomes, there were no significant differences in the postoperative Unified Parkinson's disease rating scale and levodopa equivalent drug dosage between the GA and the LA groups. Similarly, the adverse events and target accuracy were also comparable between the groups.

CONCLUSIONS

This systematic review and meta-analysis shows that currently there is no good quality data to suggest equivalence of GA to LA during STN-DBS insertion in patients with PD, with some factors trending towards LA. There is a need for a prospective randomized control trial to validate our results.

The Effects of Dexmedetomidine on Microelectrode Recordings of the Subthalamic Nucleus during Deep Brain Stimulation Surgery: A Retrospective Analysis

BACKGROUND

The placement of subthalamic nucleus (STN) deep brain stimulation (DBS) electrodes can be facilitated by intraoperative microelectrode recording (MER) of the STN.

OBJECTIVES

Optimal anesthetic management during surgery remains unclear because of a lack of quantitative data of the effect of anesthetics on MER. Therefore, we measured the effects of dexmedetomidine (DEX) on MER measures of the STN commonly taken intraoperatively.

METHODS

MER from 45 patients was retrospectively compared between patients treated with remifentanil (REMI) alone or both REMI and DEX, which are the 2 main standards of care at our center. The measures examined were population activity, such as root mean square, STN length, and number of passes yielding STN, and the single-neuron measures of firing rate and variability.

RESULTS

The addition of DEX does not affect population measures (number of passes: DEX+REMI, n = 68, REMI only, n = 154), or neuronal firing rates (number of neurons: DEX+REMI, n = 64, REMI only, n = 72), but firing rate variability was reduced.

CONCLUSIONS

In this cohort, population-based measures routinely used for electrode placement in the STN were unaffected by DEX when added to REMI. Neuronal firing rates were also unaffected, but their variability was reduced, even beyond 20 min after cessation.

Neurophysiological comparisons of subthalamic deep-brain stimulation for Parkinson's disease between patients receiving general and local anesthesia

Objectives:

Subthalamic nucleus deep-brain stimulation (STN-DBS) is suggested as a standard treatment for patients with Parkinson's disease (PD) and drug-related side effects. Most centers perform the operation under local anesthesia (LA) to ensure better microelectrode recording (MER). Given the advances in imaging and MER, general anesthesia (GA) is perceived as an alternative choice for PD patients undergoing STN-DBS. However, the outcomes in terms of clinical symptoms and MER after GA have rarely been reported. In this report, we compared the outcomes after STN-DBS for PD between patients receiving LA and GA.

Materials and Methods:

We included 16 patients with comparable severity of PD undergoing either GA (n = 8) or LA (n = 8) for STN-DBS. MER was performed in all patients for STN localization, and surgical outcomes were evaluated using the Unified PD Rating Scales, and Mini-mental status examination. All adverse effects were documented.

Results:

Both groups (GA and LA) acquired similar benefits from STN-DBS, and there were no significant differences in neuropsychiatric outcome analysis between groups. There were no significant differences in stimulation parameters and adverse effects from STN-DBS between groups. The GA group had a trend toward a lower frequency rate of STN firing on MER.

Conclusion:

Although the GA group has a lower neuronal firing frequency in the STN during surgery, STN-DBS under GA showed comparable and non-inferior outcomes as compared with STN-DBS under LA.

Bilateral Deep Brain Stimulation of the Subthalamic Nucleus under Sedation with Propofol and Fentanyl

Awakening during deep brain stimulation (DBS) surgery may be stressful to patients. The aim of the current study was to evaluate the effect on MER signals and their applicability to subthalmic nucleus (STN) DBS surgery for patients with Parkinson’s disease (PD) under sedation with propofol and fentanyl. Sixteen consecutive patients with PD underwent STN-DBS surgery with propofol and fentanyl. Their MER signals were achieved during the surgery. To identify the microelectrodes positions, the preoperative MRI and postoperative CT were used. Clinical profiles were also collected at the baseline and at 6 months after surgery. All the signals were slightly attenuated and contained only bursting patterns, compared with our previous report. All electrodes were mostly located in the middle one third part of the STN on both sides of the brain in the fused images. Six months later, the patients were improved significantly in the medication-off state and they met with less dyskinesia and less off-duration. Our study revealed that the sedation with propofol and fentanyl was applicable to STN-DBS surgery. There were no significant problems in precise positioning of bilateral electrodes. The surgery also improved significantly clinical outcomes in 6-month follow-up.

Dorsolateral subthalamic neuronal activity enhanced by median nerve stimulation characterizes Parkinson’s disease during deep brain stimulation with general anesthesia

OBJECT

Deep brain stimulation (DBS) surgery under general anesthesia is an alternative option for patients with Parkinson’s disease (PD). However, few studies are available that report whether neuronal firing can be accurately recorded during this condition. In this study the authors attempted to characterize the neuronal activity of the subthalamic nucleus (STN) and elucidate the influence of general anesthetics on neurons during DBS surgery in patients with PD. The benefit of median nerve stimulation (MNS) for localization of the dorsolateral subterritory of the STN, which is involved in sensorimotor function, was explored.

METHODS

Eight patients with PD were anesthetized with desflurane and underwent contralateral MNS at the wrist during microelectrode recording of the STN. The authors analyzed the spiking patterns and power spectral density (PSD) of the background activity along each penetration track and determined the spatial correlation to the target location, estimated mated using standard neurophysiological procedures.

RESULTS

The dorsolateral STN spiking pattern showed a more prominent bursting pattern without MNS and more oscillation with MNS. In terms of the neural oscillation of the background activity, beta-band oscillation dominated within the sensorimotor STN and showed significantly more PSD during MNS (p < 0.05).

CONCLUSIONS

Neuronal firing within the STN could be accurately identified and differentiated when patients with PD received general anesthetics. Median nerve stimulation can enhance the neural activity in beta-band oscillations, which can be used as an index to ensure optimal electrode placement via successfully tracked dorsolateral STN topography.

Controlled general anaesthesia for subthalamic nucleus stimulation in Parkinson's disease

OBJECTIVE

To report the short-term (1 year) and long-term (5 years) outcome of patients with Parkinson's disease (PD) with subthalamic nucleus (STN) stimulation operated upon under controlled general anaesthesia (GA).

METHODS

213 consecutive patients with PD were included between January 2000 and March 2009 and operated upon under a particular type of GA with close control of the level of sedation allowing intraoperative recordings. 188 patients were assessed 1 year postoperatively. 65 patients also completed the long-term observation period and were evaluated 5 years postoperatively.

RESULTS

The Unified PD Rating Scale III score in the 'Off drug--On stim' condition was improved at 1 year and 5 years by 61% and 37%, respectively, (p<0.001). Motor complications decreased at short-term and long-term by 68% and 65%, respectively, for dyskinesia and by 52% and 48%, respectively, for fluctuations, (p<0.001). Dopaminergic treatment could also be reduced at short-term and long-term by 46% and 49%, respectively (p<0.001). There was no significant modification of mood and cognition assessments (Mattis scale and Beck depression inventory) at 1 year and 5 years. Concerning the main adverse events related to the surgery, we report four haematomas (1.9%) with two deaths (0.9%), eight cases of transient confusion (3.7%) and no epileptic seizure.

CONCLUSIONS

Our results confirm that STN stimulation performed under controlled GA is efficient and has similar short-term and long-term motor effects than intervention under local anaesthesia. Furthermore, this specific procedure is not associated with more adverse events. The success of such an intervention requires strict anaesthetic monitoring and accurate STN identification.

Anesthetic challenges for deep brain stimulation: a systematic approach

Ablative intracranial surgery for Parkinson's disease has advanced to embedding electrodes into precise areas of the basal ganglia. Electrode implantation surgery, referred to as deep brain stimulation (DBS), is preferred in view of its reversibility, adjustability, and capability to be safely performed bilaterally. DBS is been increasingly used for other movement disorders, intractable tremors epilepsy, and sometimes chronic pain. Anesthesiologists need to amalgamate the knowledge of neuroanatomical structures and surgical techniques involved in placement of microelectrodes in defined cerebral target areas. Perioperative verbal communication with the patient during the procedure is quintessential and may attenuate the need for pharmacological agents. This review will endeavor to assimilate the present knowledge regarding the patient selection, available/practiced anesthesia regimens, and perioperative complications after our thorough search for literature published between 1991 and 2013.

Influence of propofol and fentanyl on deep brain stimulation of the subthalamic nucleus

We investigated the effect of propofol and fentanyl on microelectrode recording (MER) and its clinical applicability during subthalamic nucleus (STN) deep brain stimulation (DBS) surgery. We analyzed 8 patients with Parkinson's disease, underwent bilateral STN DBS with MER. Their left sides were done under awake and then their right sides were done with a continuous infusion of propofol and fentanyl under local anesthesia. The electrode position was evaluated by preoperative MRI and postoperative CT. The clinical outcomes were assessed at six months after surgery. We isolated single unit activities from the left and the right side MERs. There was no significant difference in the mean firing rate between the left side MERs (38.7 ± 16.8 spikes/sec, n=78) and the right side MERs (35.5 ± 17.2 spikes/sec, n=66). The bursting pattern of spikes was more frequently observed in the right STN than in the left STN. All the electrode positions were within the STNs on both sides and the off-time Unified Parkinson's Disease Rating Scale part III scores at six months after surgery decreased by 67% of the preoperative level. In this study, a continuous infusion of propofol and fentanyl did not significantly interfere with the MER signals from the STN. The results of this study suggest that propofol and fentanyl can be used for STN DBS in patients with advanced Parkinson's disease improving the overall experience of the patients.

Deep brain stimulation: Subthalamic nucleus electrophysiological activity in awake and anesthetized patients

OBJECTIVE

The purpose of this study was to evaluate changes in subthalamic nucleus (STN) neuronal activity in Parkinson's disease (PD) patients during deep brain stimulation (DBS) surgery under general anesthesia, and to compare these data with those recorded in the same subjects during previous surgery under local anesthesia.

METHODS

Five patients with advanced PD, who had previously undergone bilateral STN-DBS under local anesthesia, underwent re-implantation under general anesthesia (with an anesthetic protocol based on the intravenous infusion of remifentanyl and ketamine) owing to surgical device complications. The microelectrode recording (MER) data obtained were analyzed by an off-line spike-sorting software. Neurophysiological data (number of spikes detected, mean firing rate, pause index and burst index) obtained under local and general anesthesia were then evaluated and compared by means of statistical analysis.

RESULTS

We found no statistically significant difference between the first and second surgical procedures in any of the neurophysiological parameters analyzed.

CONCLUSIONS

Bilateral STN-DBS for advanced PD with MER guidance is possible and reliable under a ketamine-based anesthetic protocol.

SIGNIFICANCE

General anesthesia can be proposed for those patients who do not accept an "awake surgery" for clinical reasons, such as excessive fear, poor cooperation or severe "off"-medication effects.

Targeting the subthalamic nucleus for deep brain stimulation--a comparative study between magnetic resonance images alone and fusion with computed tomographic images

BACKGROUND

The aim of this study is to determine whether stereotactic computed tomographic (CT) images fused with magnetic resonance images (MRI) is superior to stereotactic MRI alone in accuracy for targeting the subthalamic nucleus (STN) in deep brain stimulation (DBS).

METHODS

During 2006 to 2007, 21 consecutive patients with Parkinson's disease were enrolled in this retrospective cohort study. CT Fusion group included 10 patients who underwent 20 procedures of STN-DBS under MRI-directed targeting in which the MRIs were fused to stereotactic CT images for surgical coordinates. MRI group included 11 patients who underwent 20 procedures under MRI-directed targeting alone.

RESULTS

After DBS surgery, in comparison to baseline levodopa (L-dopa) OFF, Unified Parkinson Disease Rating Scale, Part III scores improved by 43.6% ± 20.3% and 39.0% ± 15.6% (P = 0.60) in CT Fusion group and MRI group, respectively (L-dopa OFF/DBS ON). The mean decrease in L-dopa equivalent daily dose was 38.9% ± 26.3% and 36.7% ± 30.5% (P = 0.87), respectively. Single microelectrode recording (MER) trajectory procedure was experienced in 65% of patients in the CT Fusion group (13/20) and 45% of patients in the MRI group (9/20). The mean recorded STN length from initial to final MER trajectory in the CT Fusion and MRI groups was 4.3 mm (standard deviation [SD] = 1.8 mm)/5.1 mm (SD = 0.5 mm) and 3.6 mm (SD = 1.7 mm) (P = 0.214)/4.5 mm (SD = 0.7 mm) (P = 0.006), respectively. The final recorded STN length was significantly longer in the CT Fusion group.

CONCLUSIONS

In-frame-based stereotactic STN targeting, an image fusion technique between stereotactic CT and MRI, can record a significantly longer STN length through limited MER compared with MRI alone. Whether this could translate into better clinical outcome and less morbidity still need a large and randomized trial.

An assessment of current brain targets for deep brain stimulation surgery with susceptibility-weighted imaging at 7 tesla

BACKGROUND

Deep brain stimulation (DBS) surgery is used for treating movement disorders, including Parkinson disease, essential tremor, and dystonia. Successful DBS surgery is critically dependent on precise placement of DBS electrodes into target structures. Frequently, DBS surgery relies on normalized atlas-derived diagrams that are superimposed on patient brain magnetic resonance imaging (MRI) scans, followed by microelectrode recording and macrostimulation to refine the ultimate electrode position. Microelectrode recording carries a risk of hemorrhage and requires active patient participation during surgery.

OBJECTIVE

To enhance anatomic imaging for DBS surgery using high-field MRI with the ultimate goal of improving the accuracy of anatomic target selection.

METHODS

Using a 7-T MRI scanner combined with an array of acquisition schemes using multiple image contrasts, we obtained high-resolution images of human deep nuclei in healthy subjects.

RESULTS

Superior image resolution and contrast obtained at 7 T in vivo using susceptibility-weighted imaging dramatically improved anatomic delineation of DBS targets and allowed the identification of internal architecture within these targets. A patient-specific, 3-dimensional model of each target area was generated on the basis of the acquired images.

CONCLUSION

Technical developments in MRI at 7 T have yielded improved anatomic resolution of deep brain structures, thereby holding the promise of improving anatomic-based targeting for DBS surgery. Future study is needed to validate this technique in improving the accuracy of targeting in DBS surgery.

Propofol decreases neuronal population spiking activity in the subthalamic nucleus of Parkinsonian patients

BACKGROUND

Implantation of deep brain stimulation (DBS) electrodes in the subthalamic nucleus (STN) for the treatment of Parkinson disease is often performed using microelectrode recording (MER) of STN population spike activity. The extent to which sedative drugs interfere with MER is unknown. We recorded the population activity of STN neurons during propofol sedation and examined its effect on neuronal activity.

METHODS

The procedure was performed during DBS surgery for Parkinson disease. We administered propofol (50 μg/kg/min) at a constant electrode location in the STN until stable sedation was achieved. We recorded the electrical activity, and calculated its root mean square (RMS) before, during, and after the propofol infusions.

RESULTS

The activity of 24 electrode trajectories was recorded in 16 patients. The RMS of STN activity decreased significantly after propofol administration in 18 of the 24 trajectories. The average normalized RMS decreased by 23.2%± 9.1% (mean ± SD) during propofol administration (P < 0.001), and returned to baseline 9.3 ± 4.0 minutes after it was stopped.

CONCLUSIONS

Propofol administration leads to a significant decrease of STN neuronal activity. Thus, it may interfere with MER identification of the STN borders. However, activity returns to baseline shortly after administration stops. Therefore, propofol can be safely used until shortly before MER for DBS.

Review article: anesthetic management of patients undergoing deep brain stimulator insertion

Deep brain stimulation is used for the treatment of patients with neurologic disorders who have an alteration of function, such as movement disorders and other chronic illnesses. The insertion of the deep brain stimulator (DBS) is a minimally invasive procedure that includes the placement of electrodes into deep brain structures for microelectrode recordings and intraoperative clinical testing and connection of the DBS to an implanted pacemaker. The anesthetic technique varies depending on the traditions and requirements of each institution performing these procedures and has included monitored anesthesia with local anesthesia, conscious sedation, and general anesthesia. The challenges and demands for the anesthesiologist in the care of these patients relate to the specific concerns of the patients with functional neurologic disorders, the effects of anesthetic drugs on microelectrode recordings, and the requirements of the surgical procedure, which often include an awake and cooperative patient. The purpose of this review is to familiarize anesthesiologists with deep brain stimulation by discussing the mechanism, the effects of anesthetic drugs, and the surgical procedure of DBS insertion, and the perioperative assessment, preparation, intraoperative anesthetic management, and complications in patients with functional neurologic disorders.

Parkinson's disease and deep brain stimulator placement

Deep brain stimulation (DBS) has added to the comfort and quality of life for an increasing number of Parkinson's disease (PD) patients. The anesthesiologist needs to understand the pathophysiology of the disease, the surgical procedure, and its postoperative implications to most effectively manage these patients. This article examines the role of the anesthesiologist in the pre- and perioperative management of patients undergoing DBS procedures. In terms of the general anesthetic management of PD patients, it is clear that no simple anesthetic regimen exists. Anesthesiologists can provide the best care through preoperative assessment, maintenance of PD drug therapy, and avoidance of known precipitating agents.

Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 February 2008 and 31 January 2009 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.