Parkinson’s Diseases is a slowly progressive neurodegenerative disorder. It results from dopamine depletion caused by degeneration of dopaminergic nigrostriatal system, leading to a neurotransmitter imbalance between dopamine and acetylecholine in corpus striatum part of the brain. It is expressed in the form of symptoms and signs that include akinesia (loss or impairment of the ability to initiate voluntary movement), tremor, rigidity (inflexibility or stiffness) and unstable posture.
Parkinson’s disease is an extremely disabling neurological disease causing a steep fall in quality of life and enormous patient suffering. However there are various measures that we can take to control the disease, improve the quality of life, ensure patient independence in daily activities and reduce disease related suffering significantly. All these goals can be achieved mainly with the help of 3 strategies, including rehabilitation measures, medical treatment and surgical intervention.
Surgical treatment once used to be the only option for the patients with Parkinson’s Disease. However surgical intervention disappeared from the scene of Parkinson’s Disease treatment when levodopa was introduced in 1960s. It was mainly abandoned due to serious side effects and permanently disabling complications. With the recent emergence of better imaging and better understanding of brain function especially that of basal ganglia and their circuitry has generated new interest in the surgical options for Parkinson’s Disease. With the help of latest technology it has become easy to identify target structure and now surgical treatment is considered an option in patients who have symptoms unresponsive to medical treatment and whose general medical status is good.
During a surgical intervention specific structures are targeted, which include ventral intermediate nucleus of the thalamus, globus pallidus pars interna, subthalamic nucleus and striatum, mainly posterior putamen.
The procedures that are used to intervene include ablative procedures, deep brain stimulation procedures and restorative procedures.
1. Ablative Procedures:
The list of ablative procedures includes Thalamotomy, Pallidotomy and Subthalamotomy.
Severe tremors causing significant disability are a strong indication for carrying out Thalamotomy. These tremors can be either due to predominantly tremor causing Parkinson’s Disease or essential tremors. Thalamotomy provides relief in contralateral tremors and to some extent relieves akinesia and rigidity. An added advantage is that it is readily available at many centers so that it is not a rare procedure.
Akinesia and rigidity associated with Parkinson’s disease respond well to Pallidotomy. There is some positive outcome regarding other Parkinson’s disease symptoms with this procedure. This procedure is also commonly available at various centers, which is an added advantage.
Surgeons usually are not very confident at destroying subthalamic nucleus as it may cause hyperkinesias and even hemiballismus. That’s why this procedure is rarely carried out.
IV. Disadvantages of Ablative Procedures:
Since these procedures involve inflicting damage to certain parts of brain hence these have to be extremely targeted and accurate. If not so accurate these procedures can result in damage to cerebral cortex and other vital parts of brain. The worst fear is of not getting the desired result and even worsening of symptoms. Parkinson’s Disease is a bilateral pathology and unilateral treatment does not provide desired results while bilateral procedures can cause abnormalities of speech, swallowing and higher mental function. Pallidotomy may result in damage to internal capsule and visual pathways and these procedures once done leave little room for any other effective treatment.