During deep brain stimulation surgery for Parkinson's disease, the patient is usually awake so doctors can test whether the electrode has been placed correctly. Not necessary, according to the thesis of neurosurgeon Saman Vinke of the Radboud university medical center. An MRI scan can replace measurements and tests during surgery. This allows for surgery under anesthesia and enables the doctors to perform two instead of one surgical procedure per day. The anesthesia particularly attracts women with Parkinson’s, who are less likely to opt for surgery while awake.
Tremors, slowness of movement and stiffness, these are annoying symptoms of Parkinson's disease. Small surges of electricity in the brain, called deep brain stimulation (DBS), can help. To achieve this, a neurosurgeon places two electrodes through holes in the skull in a deep part of the brain. Through a pacemaker, the electrodes deliver electrical impulses, which can greatly reduce the symptoms. Three hundred of these procedures are performed in the Netherlands each year.
In the classic surgical method, the patient is awake most of the time. ‘This method is thirty years old’, explains neurosurgeon Saman Vinke. ‘The surgeon uses small currents to find the right place for the electrodes. Thanks to the awake state, the surgeon can immediately check whether the symptoms improve.’ But there are disadvantages to this classic method. For example, the operation takes almost an entire working day, most of which the patient is awake while the head is fixed. In addition, the patient must temporarily stop taking medication and therefore the symptoms increase.
Vinke studied whether measurements and tests during surgery, which require a patient to be awake and off medication, help determine the best location of the DBS electrode. ‘Such an electrode has the size of a spaghetti string. We place it in a nucleus in the brain the size of a coffee bean, called the subthalamic nucleus’, Vinke explains. ‘We now use a tailored MRI scan, which allows us to properly visualize the coffee bean. Our study shows that the measurements and tests do not contribute to determine the right spot in the placement of the spaghetti string, when we use the MRI.’
Thanks to this MRI scan, doctors can perform the surgery under anesthesia, which offers major advantages. Vinke: ‘The procedure is much shorter. We can now perform the procedure in two patients in one day instead of one. In addition, patients continue to take their medications as usual, keeping their symptoms stable.’
Another striking advantage Vinke describes in his dissertation is that women in particular are much more likely to choose for DBS surgery if it can be done under anesthesia. ‘Parkinson's occurs in forty percent of cases in women. But in our study, only seventeen percent of patients with the traditional surgical method were women’, Vinke explains. ‘Since we started operating under anesthesia, that percentage has increased to over forty percent, just as the disease is distributed in the population.’ Why women opt less for awake surgery Vinke could not find out. This will be investigated further in follow-up research.
Tip of the iceberg
The Radboudumc now only performs DBS surgery for Parkinson’s using MRI-guidance and under general anesthesia. Worldwide, by far the majority of surgeries are still performed using the traditional awake or partly awake method. Surgeons from abroad regularly come to see how the new method works. Vinke: ‘I think we could perform this operation much more often. However, the procedure is not suitable for everyone and also has side effects, so we have to take that into account, but we are still only treating the tip of the iceberg.’
More information on this thesis defense
Thesis defense on January 20, 2023 at 12:30 p.m. by Saman Vinke. Thesis title: Paradigm shifts in the surgical treatment of parkinson's disease (available online after Jan. 20). Supervisor: Prof. Dr. R.H.M.A Bartels. Co-supervisors: Dr. R.A.J. Esselink and Dr. P.L. Kubben (Maastricht UMC+). The defense can be followed via this livestream.