Thursday, September 10, 2015

Emerging Trends in Neurology and Neurosurgery: Awake Craniotomy and Stereotactic Surgery

Emerging Trends in Neurology and Neurosurgery

Awake craniotomy and Stereotactic neurosurgery have become the latest trend in Neurosurgery. Some of the neurologic conditions which were treated medically can be treated successfully by these methods. At the outset I would like to state here that eventhough I am a health care professional I have not done or witnessed any of the procedures which are discussed below. These are compilations from the websites of reputed institutions where these procedures are done.

Awake Crniotomy and Stereotactic Surgery

This article gives an overview about
  • Surgery for Intractable Tremor

  • Surgery for Parkinson’s Disease

  • Surgery for Epilepsy

  • Psychiatric Neurosurgery

Surgery for Intractable Tremor

  • Tremor is an involuntary rhythmical movement of the muscles
  • Classification of tremor:
    Tremors at rest-tremors when the hands are in resting position
  • Postural tremors-tremors when the hands held up
  • Intentional tremors- tremors during movement
Essential tremor is intentional tremor which is disabling and which is not due to Parkinsonism or other neurological disorders like cerebrovascular accidents, trauma or multiple sclerosis. In these disorders patients may suffer from tremors because of injury to the cerebellar tracts. In essential tremor even though there are no other major symptoms, the tremors can be disabling and may interfere with the patient’s activities of daily living like feeding, bathing or holding objects.

Thalamotomy or Thalamic Stimulation as treatment for Essential Tremors

  • In thalamotomy, a small lesion is placed in the thalamus in an effort to abolish the tremor.
  • In thalamic stimulation a probe is placed and stimulated with varying intensity to control the tremors.
Patients of essential tremors with significant disability are considered for surgery when it is found that their tremors are refractory to medical treatment.
The drugs usually given for patients with essential tremors are
  • propanolol
  • mysoline
  • and clonazepam.
The patients are considered for surgery after extensive evaluation by a team of experts and detailed investigation for a confirmation of diagnosis.
The procedure discussed here is done when the patient is awake and with local anesthesia as the full co-operaton of the patient is required. The author of this article has not witnessed such surgeries as they are done only in few very highly reputed neurologic centers in the world.

Surgery for Parkinson’s Disease

The neurosurgical treatment for Parkinson’s disease is based on the model of the role of basal ganglia in movement disorders.
  • Neurosurgical treatment of Parkinson’s disease include implantation of deep brain stimulators in the globus pallidus interna (Gpi), the subthalamic nucleus (STN) or the Vim nucleus of the thalamus or the creation of small lesion in Gpi (Pallidotomy) or the Vim nucleus of the thalamus (Thalamatomy).
The patient is selected for surgery after detailed evaluation by the experts.
Parkinson’ disease is caused by a loss of dopaminergic neurons in the substantia nigra which is a part of basal ganglia. Parkinson’s disease is treated medically with precursors of dopamine like levodopa and carbidopa as dopamine does not cross the blood brain barrier. Surgery for Parkinson’s disease is considered usually when the medical therapy fails. Sedating agents and general anesthesia are avoided during the surgery to ensure full cooperation of the patient during the procedure.

Epilepsy Surgery

Seizures are a very disturbing phenomenon occurring as a result of some diseases of the brain or even without that. Seizures interfere with the functional level of the patients. People with history of seizures have to take precautions about a number of things in their daily life like driving, going near the waters and fire, to avoid deprivation of sleep, to avoid stimulants like alcohol etc. Anyone suffering from seizures would hope for a much more free life by putting an end to their sufferings.
It is observed that 20-30% of patients with intractable seizures are estimated to be because of some lesions in the brain. These lesions can be identified with the help of an MRI scan. There can also be an epileptogenic focus surrounding the lesion.
So the surgery for epilepsy may either be a removal of the structural lesion or it may be the removal of the structural lesion and the epileptogenic focus.