pallidotomy

The internal globus pallidus can be regarded as an "output structure" of the basal ganglia.{{cite journal|last1=Middleton|first1=Frank A.|last2=Strick|first2=Peter L.|year=2000|title=Basal Ganglia Output and Cognition: Evidence from Anatomical, Behavioral, and Clinical Studies|journal=Brain and Cognition|volume=42|issue=2|pages=183–200|doi=10.1006/brcg.1999.1099|pmid=10744919|s2cid=16048706 |citeseerx=10.1.1.322.734}} It processes input from nucleus accumbens and the striatum, and sends input to the cerebral cortex via the thalamus. It is critical for the functioning of the basal ganglia.

Pallidotomy is an alternative to deep brain stimulation for the treatment of the involuntary movements known as dyskinesias which can become a problem in people with Parkinson's disease after long-term treatment with levodopa — a condition known as levodopa-induced dyskinesia.{{cite book |first1=W.H. |last1=Oertel |first2=A.|last2= Berardelli |first3=B.R. |last3=Bloem |first4=U. |last4=Bonuccelli |first5=D. |last5=Burn |first6=G. |last6=Deuschl |last7=Dietrichs |first7=E. |display-authors=6 |chapter=Late (complicated) Parkinson's disease |editor1-first=Nils Erik |editor1-last=Gilhus |editor2-first=Michael R. |editor2-last=Barnes |editor3-first=Michael |editor3-last=Brainin |title=European Handbook of Neurological Management |chapter-url=http://www.efns.org/fileadmin/user_upload/guidline_papers/EFNS_guideline_2011_Late__complicated__Parkinsons_disease.pdf |access-date=31 October 2012 |edition=2nd |volume=I |year=2011|publisher=Blackwell |isbn=978-1-405-18533-2 |pages=240–1}} Whilst it used to be used a primary treatment for Parkinson's disease, it has been mainly replaced by levodopa.

Pallidotomy may sometimes used to treat difficult cases of essential tremor as an alternative to deep brain stimulation.{{cite journal |doi=10.1159/000120426 |title=Clinical Cases where Lesion Therapy Was Chosen over Deep Brain Stimulation |year=2008 |last1=Hooper |first1=Amanda K. |last2=Okun |first2=Michael S. |last3=Foote |first3=Kelly D. |last4=Fernandez |first4=Hubert H. |last5=Jacobson |first5=Charles |last6=Zeilman |first6=Pamela |last7=Romrell |first7=Janet |last8=Rodriguez |first8=Ramon L. |journal=Stereotactic and Functional Neurosurgery |volume=86 |issue=3 |pages=147–52 |pmid=18334856|s2cid=1228101 }} It may also be used for dystonia, and hemiballismus.{{Cite book|last1=Smith|first1=K. A.|chapter-url=https://www.sciencedirect.com/science/article/pii/B9780123851574007739|title=Encyclopedia of the Neurological Sciences - Reference Module in Neuroscience and Biobehavioral Psychology|last2=Javedan|first2=S. P.|last3=Shetter|first3=A. G.|publisher=Academic Press|year=2014|isbn=978-0-12-385158-1|edition=2nd|pages=778–780|language=en|chapter=Pallidotomy|doi=10.1016/B978-0-12-385157-4.00773-9}}

Unilateral posteroventral pallidotomy can be effective at reducing Parkinsonism. However, it is associated with impaired language learning (if performed on the dominant hemisphere) or impaired visuospatial constructional ability (if performed on the non-dominant hemisphere). It can also impair executive functions.{{cite journal |doi=10.1212/WNL.51.1.207 |title=Neuropsychological consequences of posteroventral pallidotomy for the treatment of Parkinson's disease |year=1998 |last1=Trepanier |first1=L. L. |last2=Saint-Cyr |first2=J. A. |last3=Lozano |first3=A. M. |last4=Lang |first4=A. E. |journal=Neurology |volume=51 |pages=207–15 |pmid=9674804 |issue=1|s2cid=30517616 }} Bilateral pallidotomy will not reduce Parkisonistic symptoms.{{cite journal|last1=Merello|first1=M|last2=Starkstein|first2=S|last3=Nouzeilles|first3=MI|last4=Kuzis|first4=G|last5=Leiguarda|first5=R|year=2001|title=Bilateral pallidotomy for treatment of Parkinson's disease induced corticobulbar syndrome and psychic akinesia avoidable by globus pallidus lesion combined with contralateral stimulation|journal=Journal of Neurology, Neurosurgery & Psychiatry|volume=71|issue=5|pages=611–4|doi=10.1136/jnnp.71.5.611|pmc=1737599|pmid=11606671}}{{cite journal|last1=Ghika|first1=Joseph|last2=Ghika-Schmid|first2=Florence|last3=Fankhauser|first3=Heinz|last4=Assal|first4=Gil|last5=Vingerhoets|first5=François|last6=Albanese|first6=Alberto|last7=Bogousslavsky|first7=Julien|last8=Favre|first8=Jacques|year=1999|title=Bilateral simultaneous posteroventral pallidotomy for the treatment of Parkinson's disease: Neuropsychological and neurological side effects|journal=Journal of Neurosurgery|volume=91|issue=2|pages=313–21|doi=10.3171/jns.1999.91.2.0313|pmid=10433321|s2cid=16499763 }} It will cause severe apathy and depression, along with slurred, unintelligible speech, drooling, and pseudobulbar palsy.

The surgery itself can cause complications. Damage to a blood vessel may cause intracranial haemorrhage. Damage to the optic tract can cause a permanent vision problem. Pressure on brain tissue can induce a seizure.

Pallidotomy involves placing a tiny electrical probe in the globus pallidus, one of the basal ganglia of the brain. A craniotomy (temporary hole in the skull) needs to be created. The probe is guided based on stereotactic information, and sometimes magnetic resonance imaging. The globus pallidus is heated for a short time to destroy a small area of brain cells.

Pallidotomy has been used to treat Parkinson's disease since at least the 1950s. Older techniques involved occluding the anterior choroidal artery, with lower success rates and more side effects.

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{{Central nervous system tests and procedures}}

Category:Neurosurgical procedures