Restorative/Functional Neurosurgery :
This is a subspecialisation of neurosurgery which basically involves surgery for the physiological problems of brain. The brain is different from other organs like heart, Kidney in that the structure and the function do not go together always. The classical examples are patients with severe head injury or patients with epilepsy. Restorative or functional neurosurgery deals with usually normal scans and investigations.
The Procedures in Re Restorative/Functional neurosurgery include
- Deep brain stimulation (DBS)
- Intrathecal drug delivery systems especially morphine and baclofen.
- Spinal cord stimulation
- Sacral nerve stimulation
- Epilepsy surgery
- Vagal nerve stimulation
Deep brain stimulation (DBS) involves stimulating various parts of the brain for various pathologies. The usual indications are
- Movement disorders Parkinsonism, dystonias, essential tremor.
- Some psychiatric problems like depression, OCD, Tourette’s syndrome etc.
- Intractable alcoholism
- Chronic pain especially the central post stroke pain.
- Intractable epilepsy
- Intractable obesity
- Some types of autism (aggressive types with self harm).
- Cases of schizophrenia.
- Eating disorders like anorexia nervosa
For each disease, a specific target area/nucleus of the brain is used. For example for Parkinson’s disease, the target is Subthalamic nucleus; for depression it is the subcallosal cingulate area.
The commonest movement disorder is Parkinson’s disease which manifests with tremors, rigidity, slow movement (bradykinesia), poor balance, and difficulty in walking. It affects 1 – 2% of people above 60 yrs but in India it is seen in younger people also (upto 15%). Treatment of movement disorders like Parkinson’s disease is predominantly by drugs and drugs are very effective in most cases. But a good number of patients either come out of good control in the long term or develop side effects of drugs. Such patients are surgical candidates. DBS is offered in patients with Parkinson’s disease when the medical management is becoming ineffective or causing significant side effects. Symptoms which are improved by drug therapy are maximally improved with surgery with remor 80%-100%, Slowness (Bradykinesia) 50%-60%, Stiffness (Rigidity) 50%-70%, Gait, Freezing, and Balance 50%, Dyskinesias & Dystonia (drug induced) 80%- 90%. Motor fluctuations are virtually eliminated and independence and quality of life substantially improved. Complications include haemorrhage (2-3%), Infection (1 -3%), mechanical hardware breakage (1-5%) and cognitive decline (2%).
1. DBS of the nucleus accumbens is highly effective in all cases of addiction as also in obesity. PET studies have shown that, when an individual takes a psychoactive substance, dopamine is released in the nucleus accumbens, which causes “the high”. By an increased dopamine release in the nucleus accumbens, the inhibition of the output neurons is decreased, which causes activation of the reward. Case series and reports have shown DBS of nucleus accumbens causes reduction in alcohol, nicotine and heroin intake in human beings. Studies in lab animals have also shown the same results.
Autism spectrum disorder (ASD) is a developmental disability that can cause significant social, communication and behavioral challenges. It is becoming common in India. People with ASD often have problems with social, emotional, and communication skills. They might repeat certain behaviors and might not want change in their daily activities. There is currently no cure for ASD. One in four children with autism shows aggressive behavior, like hitting others, biting self and others, destroying property or throwing temper tantrums. DBS of amygdala is very good in significantly reducing the aggressive behaviour as well as improving communication skills.
Pain is a very common symptom and is of two types: acute and chronic. Acute pain is considered protective and of limited duration, usually seen in an acute setting and associated with external injuries, burns, surgery etc. It is well controlled by pharmacological measures. Chronic pain is of longer duration, persists long after initial injury and requires pharmacological, psychological and even surgical measures. When pain persists or recurs more than six months it is defined as chronic pain.
Pain is a very common symptom and is of two types: acute and chronic. Acute pain is considered protective and of limited duration, usually seen in an acute setting and associated with external injuries, burns, surgery etc. It is well controlled by pharmacological measures. Chronic pain is of longer duration, persists long after initial injury and requires pharmacological, psychological and even surgical measures. When pain persists or recurs more than six months it is defined as chronic pain.
- Intrathecal drug delivery
- Neurostimulation,
- Neuroablative therapies.
2. Intrathecal drug delivery system involves a pump placed in the lower abdomen subcutaneously and connected to the CSF through a subcutaneous catheter. The pump can be filled with the drug which can be delivered continuously into the CSF. The dose of the drug can be adjusted and refilling is a simple OPD procedure. Usually two drugs are used in this manner.
- Intrathecal morphine (ITM) pumps very useful in:
- cancer pains
- Failed back surgery syndromes.
- Other types of noxious pain like osteoporotic pain, osteoarthritic pain, pain of rheumatoid arthritis
- Intrathecal baclofen (ITB) pumps are good in
- All types of spasticity (including cerebral palsy/ multiple sclerosis/stroke/ traumatic paraplegics/spinal cord injury etc).
- Patients in persistent vegetative state.
- Cases of spino-cerebellar degeneration
- Cerebellar type of MS.
3) The third type of surgery in restorative neurosurgery is the Spinal cord stimulation (SCS)> This involves inserting an electrode into the dorsal extradural space of the spinal cord and connecting it to a battery placed subcutaneously. This procedure is very useful in:
- Refractory angina/ Intractable heart Failure
- Failed back surgery syndrome
- Severe diabetic neuropathy pain.
- Brachial plexus injury pain
- Severe peripheral vascular disease
- Brachial plexus injury pain
- Trigeminal neuropathy
- Post amputation/phantom limb pains
- Post herpetic neuralgia
4) The sacral nerves especially S2, S3, S4 controll the bowel and the bladder sphincters. Sacral nerve stimulation (SNS) is stimulation of the sacral nerves to modulate the reflexes that influence the bladder, sphincter, and pelvic floor. SNS utilizes mild electrical pulses to improve or restore normal voiding function. The common indications for SNS are:
- Symptoms of urinary urge incontinence
- Symptoms of urgency-frequency
- Combination of both
- Non obstructive Urinary retention/incomplete emptying
- Chronic Fecal Incontinence.
- Chronic constipation.
- Irritable bowel syndrome (esp diarrohoea type)
- Severe pelvic pain in women.
Epilepsy is a condition characterized by the occurrence of seizures with or without alterations in consciousness resulting from abnormal electrical activity in the brain. The main treatment of epilepsy is always medical. In patients who are unresponsive to or intolerant of medical therapy, surgery becomes an option. It is important to determine that all medical options have been exhausted prior to surgery. Usual surgical procedures include
- Resective (removing portions) surgery like lesionectomy, temporal lobectomy, corpus callosotomy, hemispherectomy.
- Vagal nerve stimulation (VNS).
- DBS of anterior thalamus recently
Vagus nerve stimulation (VNS) is an adjunctive treatment for certain types of intractable epilepsy and major depression. Vagus nerve stimulation (VNS) is designed to prevent seizures by sending regular, mild pulses of electrical energy to the brain via the vagus nerve. Indications include patients who have failed surgery before, require extratemporal surgery in eloquent area or corpus callosotomy or patients choice. VNS in epilepsy and depression are both FDA approved.
