One of the most common questions asked by patients who will undergo brain pacemaker, or deep brain stimulation (DBS) surgery is:
“Will I be awake during the surgery?”
The short answer: Not always.
Deep brain stimulation surgery can be performed both while the patient is awake and under general anesthesia, meaning with the patient fully asleep. Today, thanks to advanced imaging and surgical planning methods, successful results can be achieved with either approach in appropriate patients [1–4]. A randomized study also showed that motor improvement was similar after awake and general anesthesia DBS surgery in patients with Parkinson’s disease [1].
Why is the patient kept awake during surgery?
In deep brain stimulation surgery, electrodes must be placed in very small, specific areas of the brain with millimetric precision.
In the traditional approach, the patient is awake during the stage when the electrodes are placed. Local anesthesia is applied to the head area to ensure that the patient does not feel pain.
During surgery, the surgeon can speak with the patient; ask the patient to move a hand or foot; observe whether tremor decreases; or deliver temporary electrical stimulation to assess whether an unwanted effect occurs in speech, movement, or other functions [1].
Some centers also use microelectrode recordings. In this method, the electrical activity of nerve cells in the targeted brain area is recorded during surgery. This can provide the surgeon with additional information about whether the electrode has reached the correct brain area [1].
For this reason, awake surgery was the classic method of DBS surgery for many years.
Does being awake mean remaining fully awake throughout the surgery?
No.
The term “awake DBS” does not mean that the patient remains fully awake from the beginning to the end of surgery without receiving any medication.
The approach may vary according to the center and the surgical technique used. In some methods, it is sufficient for the patient to be awake during certain stages. The main purpose is to be able to communicate with the patient when necessary and to perform certain neurologic tests while the electrode is being placed.
Placement of the battery unit, which is implanted in the chest area and supplies electricity to the electrodes, can generally be performed under anesthesia. For example, in the GALAXY study, after placement of the brain electrodes in patients in the awake group, the stage in which the battery and connection system were placed was performed under general anesthesia [1].
Can deep brain stimulation surgery also be performed with the patient fully asleep?
Yes.
In recent years, DBS electrodes have also been able to be placed while the patient is under general anesthesia. This method is often called “asleep DBS”, meaning DBS performed with the patient asleep.
In this method, rather than relying on the patient’s clinical responses during surgery, imaging methods performed especially before and during surgery are used. Detailed MRI and CT images, stereotactic surgical planning systems, and intraoperative imaging performed at some centers help place the electrode at the correct location [2–4].
It should not be assumed that microelectrode recordings can be performed only in awake patients. Depending on the anesthesia technique used, microelectrode recordings can also be performed under general anesthesia. Indeed, microelectrode recordings were used in both the awake and general anesthesia groups in the GALAXY study [1].
Is surgery performed with the patient asleep less successful?
Current scientific evidence does not show this.
Studies directly comparing awake and asleep DBS surgery in patients with Parkinson’s disease have not shown a significant difference between the two methods in terms of improvement in motor symptoms [1–4].
In one of the most important studies on this subject, the GALAXY randomized clinical trial included 110 patients with Parkinson’s disease who underwent STN-DBS surgery while awake or under general anesthesia. At six months of follow-up, no significant difference in motor improvement was found between the two groups [1]. Surgery under general anesthesia was considered less burdensome by patients, and the surgery time was on average 26 minutes shorter.
Another randomized study reported that motor improvement at six months after asleep STN-DBS was similar to the results achieved with the awake approach [2].
Studies evaluating larger patient groups have also generally reported similar results between awake and asleep DBS in terms of motor improvement, quality of life, and reduction in medication use [3,4].
Therefore, today:
“A brain pacemaker must be implanted while the patient is awake.”
is not an accurate general rule.
What is the advantage of surgery performed with the patient asleep?
One of the most important advantages is patient comfort.
Surgery performed under general anesthesia may be more comfortable, especially for patients with significant anxiety about surgery, difficulty remaining in the same position for a long time, or marked tremor, muscle contractions, or involuntary movements during the period when medications are stopped.
In the GALAXY study, patients who underwent surgery under general anesthesia also considered the surgical process less burdensome than patients who underwent awake surgery [1]. In addition, being able to operate under general anesthesia on patients who may have difficulty tolerating awake surgery because of extreme restlessness, anxiety, or painful dystonia may be an important advantage [1].
So, what is the advantage of awake surgery?
One of the main advantages of awake surgery is that, while the electrode is being placed, the patient can be directly assessed clinically.
For example, when the electrode is temporarily stimulated:
- -does the tremor decrease?
- -is there improvement in movement?
- -does speech impairment occur?
- -do involuntary contractions develop in the face or arms and legs?
- -does any other side effect that bothers the patient occur?
effects such as these can be assessed during surgery [1].
This information may help determine the most appropriate electrode location in some patients and with some surgical techniques.
However, with the development of modern imaging methods, the ability to visualize target areas of the brain in much greater detail before surgery has enabled some centers to place DBS electrodes under general anesthesia without clinical testing [1–4].
Which is better: awake DBS or asleep DBS?
In fact, the right question is often not “Which is better?” but “Which method is more appropriate for this patient?”.
This is because the success of DBS surgery is not determined solely by whether the patient is awake or asleep during surgery.
More important factors are:
- -selecting the right patient,
- -determining the brain target appropriate for the patient,
- -safely placing the electrode at the correct location,
- -correctly programming the device after surgery,
- -and having the entire process carried out by an experienced team.
Current clinical studies show that, when appropriate techniques are used at experienced centers, both awake and asleep DBS surgery can be effective options [1–4].
Conclusion
A patient who will undergo deep brain stimulation surgery does not necessarily need to remain awake throughout the surgery.
Today, DBS surgery can be performed while the patient is awake or under general anesthesia. Each approach has its own advantages. Comparative studies in patients with Parkinson’s disease show that, when appropriate surgical techniques are used, both methods can provide similar motor outcomes [1–4].
The method to be preferred should be determined individually according to the patient’s characteristics, the targeted brain area, the surgical and imaging technologies to be used, and the experience of the surgical team.
Therefore, the most important aspect of deep brain stimulation surgery is not whether the patient is awake or asleep, but whether the electrode is placed safely and precisely at the correct target.
References
1. Holewijn RA, Verbaan D, van den Munckhof PM, et al. General Anesthesia vs Local Anesthesia in Microelectrode Recording-Guided Deep-Brain Stimulation for Parkinson Disease: The GALAXY Randomized Clinical Trial. JAMA Neurol. 2021;78(10):1212–1219. doi:10.1001/jamaneurol.2021.2979.
2. Engelhardt J, Caire F, Damon-Perrière N, et al. A Phase 2 Randomized Trial of Asleep versus Awake Subthalamic Nucleus Deep Brain Stimulation for Parkinson’s Disease. Stereotact Funct Neurosurg. 2021;99(3):230–240. doi:10.1159/000511424.
3. Brodsky MA, Anderson S, Murchison C, et al. Clinical outcomes of asleep vs awake deep brain stimulation for Parkinson disease. Neurology. 2017;89(19):1944–1950. doi:10.1212/WNL.0000000000004630.
4. Chen T, Mirzadeh Z, Chapple KM, et al. Clinical outcomes following awake and asleep deep brain stimulation for Parkinson disease. J Neurosurg. 2019;130(1):109–120. doi:10.3171/2017.8.JNS17883.