Anesthesia for deep brain stimulation

Delayed Recovery After Deep Brain Stimulation Surgery for Parkinson's Disease Under General Anesthesia-Cases Report

Objective

Parkinson's disease (PD) is a neurodegenerative syndrome, and deep-brain stimulation (DBS) is an effective therapy for carefully screened patients with PD. However, delayed recovery after anesthesia, which occurs after taking prolonged general anesthesia for such patients, has been reported less frequently in literature. This report explores the possible causes of postoperative awakening delay in patients undergoing DBS surgery due to general anesthesia and provides a reference for anesthesia management of similar operations in the future.

Case Presentation

Three patients with PD elective underwent DBS surgery. The first patients demonstrated walking disability, gait deficits, unstable posture, limb stiffness, and imbalance. The second demonstrated left limb static tremor, stiffness, and bradykinesia. The third demonstrated bradykinesia, rigidity, walking deficits, and decreased facial expression. These included two males and one female with a mean patient age of 60.7 ± 6.7year, weight of 63.7 ± 11 kg, the height of 163.3 ± 7.6 cm, and preoperative American Society of Anesthesiology rating of 2.3 ± 0.6. The preoperative Glasgow Coma Scale mean score was 15. All patients completed the operation under general anesthesia (the mean anesthesia time was 5.3 ± 1.1 h). The mean operation time was 252 ± 60 min. The mean bleeding volume was 50 ml, and the urine volume was 867 ± 569 ml. However, all the patients showed unconsciousness after 95 ± 22 min after stopping the anesthetic, and the respiratory function was in good condition, but they could not cooperate with anesthesiologists and had no response to the anesthesiologist's instructions. The mean hospital stay was 17 ± 7 days. All patients were discharged uneventfully. The average number of days patients followed up postoperatively was 171 ± 28.5 days. Motor and speech were improved significantly postoperatively in three patients compared with preoperatively. Taking anti-Parkinson medication was markedly reduced. There were no complications during postoperative follow-up.

Conclusions

To prevent delayed recovery occurring after DBS surgery in Parkinson's disease, it is recommended to take scalp nerve block + general anesthesia to complete the procedure while avoiding general anesthesia.

Anesthesia for deep brain stimulation: an update

PURPOSE OF REVIEW

Deep brain stimulation (DBS) is a rapidly expanding surgical modality for the treatment of patients with movement disorders. Its ability to be adjusted, titrated, and optimized over time has given it a significant advantage over traditional more invasive surgical procedures. Therefore, the success and popularity of this procedure have led to the discovery of new indications and therapeutic targets as well as advances in surgical techniques. The aim of this review is to highlight the important updates in DBS surgery and to exam the anesthesiologist's role in providing optimal clinical management.

RECENT FINDINGS

New therapeutic indications have a significant implication on perioperative anesthesia management. In addition, new technologies like frameless stereotaxy and intraoperative magnetic resonance imaging to guide electrode placement have altered the need for intraoperative neurophysiological monitoring and hence increased the use of general anesthesia. With an expanding number of patients undergoing DBS implantation, patients with preexisting DBS increasingly require anesthesia for unrelated surgery and the anesthesiologist must be aware of the considerations for perioperative management of these devices and potential complications.

SUMMARY

DBS will continue to grow and evolve requiring adaptation and modification to the anesthetic management of these patients.

Effects of dexmedetomidine on subthalamic local field potentials in Parkinson's disease

Background

Dexmedetomidine is frequently used for sedation during deep brain stimulator implantation in patients with Parkinson's disease, but its effect on subthalamic nucleus activity is not well known. The aim of this study was to quantify the effect of increasing doses of dexmedetomidine in this population.

Methods

Controlled clinical trial assessing changes in subthalamic activity with increasing doses of dexmedetomidine (from 0.2 to 0.6 μg kg⁻¹ h⁻¹) in a non-operating theatre setting. We recorded local field potentials in 12 patients with Parkinson's disease with bilateral deep brain stimulators (24 nuclei) and compared basal activity in the nuclei of each patient and activity recorded with different doses. Plasma levels of dexmedetomidine were obtained and correlated with the dose administered.

Results

With dexmedetomidine infusion, patients became clinically sedated, and at higher doses (0.5–0.6 μg kg⁻¹ h⁻¹) a significant decrease in the characteristic Parkinsonian subthalamic activity was observed (P<0.05 in beta activity). All subjects awoke to external stimulus over a median of 1 (range: 0–9) min, showing full restoration of subthalamic activity. Dexmedetomidine dose administered and plasma levels showed a positive correlation (repeated measures correlation coefficient=0.504; P<0.001).

Conclusions

Patients needing some degree of sedation throughout subthalamic deep brain stimulator implantation for Parkinson's disease can probably receive dexmedetomidine up to 0.6 μg kg⁻¹ h⁻¹ without significant alteration of their characteristic subthalamic activity. If patients achieve a ‘sedated’ state, subthalamic activity decreases, but they can be easily awakened with a non-pharmacological external stimulus and recover baseline subthalamic activity patterns in less than 10 min.

Clinical trial registration

EudraCT 2016-002680-34; NCT-02982512.

Effect of Anesthesia on Microelectrode Recordings during Deep Brain Stimulation Surgery in Tourette Syndrome Patients

BACKGROUND

Deep brain stimulation (DBS) is an accepted treatment for patients with medication-resistant Tourette syndrome (TS). Sedation is commonly required during electrode implantation to attenuate anxiety, pain, and severe tics. Anesthetic agents potentially impair the quality of microelectrode recordings (MER). Little is known about the effect of these anesthetics on MER in patients with TS. We describe our experience with different sedative regimens on MER and tic severity in patients with TS.

METHODS

The clinical records of all TS patients who underwent DBS surgery between 2010 and 2018 were reviewed. Demographic data, stimulation targets, anesthetic agents, perioperative complications, and MER from each hemisphere were collected and analyzed. Single-unit activity was identified by filtering spiking activity from broadband MER data and principal component analysis with K-means clustering. Vocal and motor tics which caused artifacts in the MER data were manually selected using visual and auditory inspection.

RESULTS

Six patients underwent bilateral DBS electrode implantation. In all patients, the target was the anterior internal globus pallidus. Patient comfort and hemodynamic and respiratory stability were maintained with conscious sedation with one or more of the following anesthetic drugs: propofol, midazolam, remifentanil, clonidine, and dexmedetomidine. Good quality MER and clinical testing were obtained in 9 hemispheres of 6 patients. In 3 patients, MER quality was poor on one side.

CONCLUSION

Cautiously applied sedative drugs can provide patient comfort, hemodynamic and respiratory stability, and suppress severe tics, with minimal interference with MER.

Effect of Dexmedetomidine and Propofol on Basal Ganglia Activity in Parkinson Disease: A Controlled Clinical Trial

BACKGROUND

Deep brain stimulation electrodes can record oscillatory activity from deep brain structures, known as local field potentials. The authors' objective was to evaluate and quantify the effects of dexmedetomidine (0.2 μg·kg·h) on local field potentials in patients with Parkinson disease undergoing deep brain stimulation surgery compared with control recording (primary outcome), as well as the effect of propofol at different estimated peak effect site concentrations (0.5, 1.0, 1.5, 2.0, and 2.5 μg/ml) from control recording.

METHODS

A nonrandomized, nonblinded controlled clinical trial was carried out to assess the change in local field potentials activity over time in 10 patients with Parkinson disease who underwent deep brain stimulation placement surgery (18 subthalamic nuclei). The relationship was assessed between the activity in nuclei in the same patient at a given time and repeated measures from the same nucleus over time.

RESULTS

No significant difference was observed between the relative beta power of local field potentials in dexmedetomidine and control recordings (-7.7; 95% CI, -18.9 to 7.6). By contrast, there was a significant decline of 12.7% (95% CI, -21.3 to -4.7) in the relative beta power of the local field potentials for each increment in the estimated peak propofol concentrations at the effect site relative to the control recordings.

CONCLUSIONS

Dexmedetomidine (0.2 μg·kg·h) did not show effect on local field potentials compared with control recording. A significant deep brain activity decline from control recording was observed with incremental doses of propofol.

Sedation During Surgery for Movement Disorders and Perioperative Neurologic Complications: An Observational Study Comparing Local Anesthesia, Remifentanil, and Dexmedetomidine

BACKGROUND

The anesthetic management of patients requiring surgery for movement disorders needs to balance microrecording quality and patient cooperation with safety and comfort. Anesthetics can alter microrecording, although the effect on outcome is debatable. They also provide a rested and cooperative patient and minimize complications such as intracranial hemorrhage by providing better hemodynamic control. Most teams use local anesthesia with monitored anesthesia care or conscious sedation with propofol. Recently, dexmedetomidine has emerged as an alternative that, at low doses, does not affect microrecording, and that does not impair respiratory drive.

METHODS

In the past 15 years, we have used in our institution local anesthesia, remifentanil, or dexmedetomidine sedation. We compared functional outcome and rate of complications in a group of 145 patients with similar characteristics.

RESULTS

We found 5 (3.4%) intracranial hemorrhages. Two (1.4%) were symptomatic. The remifentanil group had the highest risk of having systolic blood pressure >160 mm Hg during surgery (odds ratio [OR], 2.8; 95% confidence interval [CI], 0.9-9.9), whereas the dexmedetomidine group had the lowest (OR, 0.7; 95% CI, 0.2-1.8), compared with the local anesthesia group. Surgical time was shortest with dexmedetomidine (mean, 283 minutes) and longest with local anesthesia only (mean, 328 minutes). Functional outcome (Unified Parkinson's Disease Rating Scale, Part III motor component scale) was similar among groups. The dexmedetomidine group had a statistically significant lower risk of perioperative neurologic events compared with the local anesthesia group (OR, 0.09; 95% CI, 0.002-0.68).

CONCLUSIONS

Sedation can be used safely without affecting outcome, and dexmedetomidine provides better hemodynamic management. Clinical significance remains unclear and larger studies need to be undertaken.

Innovations in Functional Neurosurgery and Anesthetic Implications

Functional neurosurgery has undergone rapid growth over the last few years fueled by advances in imaging technology and novel treatment modalities. These advances have led to new surgical treatments using minimally invasive and precise techniques for conditions such as Parkinson's disease, essential tremor, epilepsy, and psychiatric disorders. Understanding the goals and technological issues of these procedures is imperative for the anesthesiologist to ensure safe management of patients presenting for functional neurosurgical procedures. In this review, we discuss the advances in neurosurgical techniques for deep brain stimulation, focused ultrasound and minimally invasive laser-based treatment of refractory epilepsy and provide a guideline for anesthesiologists caring for patients undergoing these procedures.

Anaesthesia for deep brain stimulation: a review

PURPOSE OF REVIEW

Deep brain stimulation (DBS) is a well tolerated and efficacious surgical treatment for movement disorders, chronic pain, psychiatric disorder, and a growing number of neurological disorders. Given that the brain targets are deep and small, accurate electrode placement is commonly accomplished by utilizing frame-based systems. DBS electrode placement is confirmed by microlectrode recordings and macrostimulation to optimize and verify target placement. With a reliance on electrophysiology, proper anaesthetic management is paramount to balance patient comfort without interfering with neurophysiology.

RECENT FINDINGS

To achieve optimal pain control, generous amounts of local anaesthesia are instilled into the planned incision. During the opening and closing states, conscious sedation is the prevailing method of anaesthesia. The preferred agents are dexmedetomidine, propofol, and remifentanil, as they affect neurocognitive testing the least, and shorter acting. All the agents are turned off 15-30 min prior to microelectrode recording. Dexmedetomidine has gained popularity in DBS procedures, but has some considerations at higher doses. The addition of ketamine is helpful for pediatric cases.

SUMMARY

DBS is a robust surgical treatment for a variety of neurological disorders. Appropriate anaesthetic agents that achieve patient comfort without interfering with electrophysiology are paramount.

Factors Associated with Tremor Changes during Sedation with Dexmedetomidine in Parkinson's Disease Surgery

<b><i>Introduction:</i></b> Dexmedetomidine is an α₂-agonist recently proposed as a potentially ideal drug for sedation during the surgical treatment of Parkinsonʼs disease (PD). This report documents the incidence of changes in motor symptoms (especially tremor) in PD patients sedated with dexmedetomidine for deep brain stimulation or ablation procedures. <b><i>Methods:</i></b> We reviewed a retrospective cohort of 22 patients who underwent surgery for PD with dexmedetomidine sedation at a single institution from 2010 to 2014. A logistic regression analysis was performed to analyze possible confounding factors. <b><i>Results:</i></b> 14 cases of tremor reduction or suppression were recorded (cumulative incidence: 63.6%; 95% CI: 40.7-82.8). No association could be identified between loading dose, β-blocker use and preoperative total Unified Parkinson's Disease Rating Scale III, with tremor changes. The maintenance dose of dexmedetomidine was higher in patients who did not experience changes [median and range for patients with and without tremor alteration 0.75 (0.2-1.0) and 1.0 µg × kg^-1 × h^-1 (0.7-1.4), respectively; p = 0.021]. <b><i>Conclusion:</i></b> Dexmedetomidine provides adequate sedation during surgery for PD, but it might affect motor signs making intraoperative testing difficult or even impossible. Dosage appears not to be the determining factor in motor changes, whose cause remains unclear.

[Anesthesiological aspects of deep brain stimulation : special features of implementation and dealing with brain pacemaker carriers]

Deep brain stimulation (DBS) provides a very effective treatment for a number of neurological diseases including Parkinson's disease, movement disorders and epilepsy. In DBS microelectrodes are positioned in defined cerebral target areas and connected to a pacemaker. It is most often performed as an awake craniotomy with intraoperative testing. Various anesthesiological regimes are used to protect the patient from surgical stress on the one hand and to achieve ideal test conditions on the other. They include local anesthesia or scalp blocks, intermittent general anesthesia or analgosedation with or without airway protection; however, anesthetic agents interfere with hemodynamic stability and ventilation, with vigilance and cooperation and in addition with the symptoms and microelectrode recording. Guidance and communication have a pivotal impact on patient needs for pharmacological interventions. With increasing numbers of DBS procedures, anesthesiologists are more often faced with patients carrying brain pacemakers. For anesthesia the characteristics of the disease as well as the respective long-term medication have to be considered. In addition, the rules for handling patients with pacemakers need to be followed to avoid both dysfunction of the generator and tissue damage due to overheating of the electrodes.

Differential diagnosis of psychiatric symptoms after deep brain stimulation for movement disorders

OBJECTIVES

The presence of a deep brain stimulator (DBS) in a patient with a movement disorder who develops psychiatric symptoms poses unique diagnostic and therapeutic challenges for the treating clinician. Few sources discuss approaches to diagnosing and treating these symptoms.

MATERIALS AND METHODS

The authors review the literature on psychiatric complications in DBS for movement disorders and propose a heuristic for categorizing symptoms according to their temporal relationship with the DBS implantation process.

RESULTS

Psychiatric symptoms after DBS can be categorized as preimplantation, intra-operative/perioperative, stimulation related, device malfunction, medication related, and chronic stimulation related/long term. Once determined, the specific etiology of a symptom guides the practitioner in treatment.

CONCLUSIONS

A structured approach to psychiatric symptoms in DBS patients allows practitioners to effectively diagnose and treat them when they arise.

Continuous perioperative apomorphine in deep brain stimulation surgery for Parkinson's disease

BACKGROUND

Patients with Parkinson's disease (PD) deprived of dopaminergic medication to facilitate awake testing during the deep brain stimulation (DBS) procedure are at increased risk of neurologic deterioration.. The aim of this survey was to demonstrate the safety of subcutaneous apomorphine treatment for reducing surgery-related neurologic deterioration in patients undergoing DBS surgery for PD.

METHODS

Ninety-two patients who underwent DBS surgery for PD between 11/2007 and 10/2011 in our department were retrospectively analyzed for this survey. Demographic data, apomorphine dosage, side-effects and need of ICU/IMC stay were collected and analyzed.

RESULTS

Seventy-two out of 92 patients (78.3%) received apomorphine treatment; main reason for omission of treatment was intolerable nausea (16/92, 17.3%). Apomorphine treatment was well tolerated and the most common side effect was nodular panniculitis. No severe complications were observed. No patient required ICU/IMC stay related to dopaminergic deprivation.

CONCLUSIONS

Perioperative withdrawal of dopaminergic medication in PD patients leads to an increased risk of neurologic and respiratory deterioration during DBS procedures. These complications can likely be tempered using perioperative subcutaneous apomorphine as a substitute. Our 5-year experience indicates a reduction in postoperative neurologic deterioration and ICU/IMC stay need. We consider perioperative apomorphine safe during DBS surgery for PD.

Anesthetic considerations for awake craniotomy for epilepsy and functional neurosurgery

The two most common neurosurgical procedures that call for an awake patient include epilepsy surgery and functional neurosurgery. Monitoring patients in the awake state allows more aggressive resection of epileptogenic foci in functionally important brain regions. Careful patient selection and preparation combined with attentive monitoring and anticipation of events are fundamental to a smooth awake procedure. Current pharmacologic agents and techniques at the neuroanesthesiologist's disposal facilitate an increasing number of procedures performed in awake patients.