Movement Disorders Surgery
– LESIONING – RF ablation – STIMULATION – DBS – Deep Brain Stimulation
Targets In Brain
- MOTOR THALAMUS
– Vim – Ventralis intermedius
– Vo – Ventralis Oralis (Voa, Vop, Voi)
- GPi – GLOBUS PALLIDUS INTERNUS – (PVP)
- STN – SUB THALAMIC NUCLEUS – (with options PSA, cZI & PPN) Plus many other areas.
All Movement Disorders surgeries’ are done with the patient FULLY AWAKE! Constant feedback is obtained from the patient during surgery.
STIMULATION – always done to confirm target location. Two types of stimulation exist.
-Macro stimulation- MS
-Micro Electrode stimulation & Recording – MER
RF ABLATION OR LESIONING SURGERY
Radio Frequency Ablation or RF lesioning (Thalamotomy/Pallidotomy), reduces the symptoms of movement disorders though the permanent inactivation of a precisely targeted region/ circuit of the brain. Principal targets of this therapy are the thalamus and the globus pallidus, two areas of the brain involved in movement.
RF procedures continue to play a role even in patients for whom DBS is the ideal surgery but is contraindicated or who would have difficulty maintaining the DBS device. This is also very cost effective and in selected cases, the results are excellent.
COMMON LESIONING SURGERIES
The pallidal target for surgical treatment of dystonia is located in the posteroventral lateral GPi. Whereas improvement of phasic dystonic movements may be seen early after surgery, tonic dystonic postures improve over much longer time, sometimes up to 6 months. Pallidotomy has been reported to be effective in various dystonic disorders, including generalized dystonia, segmental dystonia and hemidystonia, yielding about50–80% improvement in most studies.Patients with genetic dystonias (bothDYT-1 positive and DYT-1 negative) consistently demonstrated marked improvement, whereas this was less dramatic and less consistent in secondary dystonia.
Thalamotomy- Vim & Vo
The Thalamic target is selected in patients having either tremors or focal hand dystonias or a combination of both. The targets are in the motor thalamus and may be either the Vim, Vo or both.
In Vim or Vothalamotomy, the results are usually immediate, The surgery usually requires a 4-day hospital stay. Most people recover completely within about 6 weeks.
DEEP BRAIN STIMULATION (DBS) OR BRAIN PACEMAKER
This is a neurosurgical procedure introduced in 1987, involving the implantation of a medical device called a neurostimulator (sometimes referred to as a ‘brain pacemaker’), which sends electrical impulses, through implanted electrodes, to specific targets in the brain (brain nuclei) for the treatment of movement and neuropsychiatric disorders. DBS in select brain regions has provided therapeutic benefits for otherwise-treatment-resistant disorders such as Parkinson’s disease, essential tremor, generalized dystonia, chronic pain, major depression and -obsessive-compulsive disorder(OCD)
DBS directly changes brain activity in a controlled manner, its effects are reversible. The deep brain stimulation system consists of three components: the implanted pulse generator (IPG), the lead, and the extension. The IPG is a battery-powered neurostimulator encased in a titanium housing, which sends electrical pulses to the brain to interfere with neural activity at the target site.
A hole about 14 mm in diameter is drilled in the skull and the probe electrode is inserted stereotactically. During the awake procedure with local anesthesia, feedback from the patient is used to determine optimal placement of the permanent electrode.
The right side of the brain is stimulated to address symptoms on the left side of the body and vice versa.
Spasticity (from Greek spasmos-, meaning “drawing, pulling”) is a feature of altered skeletal muscle performance with a combination of paralysis, increased tendon reflex activity and hypertonia. It is also colloquially referred to as an unusual “tightness”, stiffness, or “pull” of muscles.
Spasticity – as a component of the upper motor neuron syndrome – is a frequently encountered clinical condition. Spasticity may be either useful – by compensating decrease in motor strength – or harmful – by limiting both passive and active motion and, in the extreme, by leading to irreducible contractures and deformities – or as in most cases and harmful and useful in the same patient. A large population of adults and children in developing countries and in wealthy societies as well is suffering from this locomotor disability.
Excess of spasticity leads to a disability that is marked by impaired locomotion and, if not controlled, handicapping deformities, discomfort, and pain. When spasticity is disabling, an effective therapeutic armamentarium is currently available. If spasticity fails to be controlled by relaxant medications and physical therapy and escapes rehabilitation rograms, neurosurgical procedures aiming to diminish the excess of tone and rebalance agonist and antagonist muscle groups can be the remedy. They may help improve function and limit irreversible deformities. Complementary orthopedic surgical corrections are often required though.
Spasticity should only be treated when excess of tone leads to further functional losses, impairs locomotion and motricity, or induces deformities. Spasticity is often treated with the drug baclofen, which acts as an agonist at GABA receptors, which are inhibitory.
Spastic cerebral palsy is the most common form of cerebral palsy, which is group of permanent movement problems that do not get worse over time. GABA’s inhibitory actions contribute to baclofen’s efficacy as an anti-spasticity agent.
Targets of lesioning procedures are the peripheral nerves (neurotomies), the spinal roots (dorsal rhizotomies), the spinal cord (myelotomies), and the dorsal root entry zone (DREZotomy). Treatment with intrathecal baclofen can be achieved thanks to modern technology, namely, the computerized programmable, implantable, pump.