corpus callosotomy

File:Gray 733-emphasizing-corpus-callosum.png

A corpus callosotomy ({{IPAc-en|k|ə|ˈ|l|ɔː|s|(|ə|)|t|ə|m|iː}}) is a palliative surgical procedure for the treatment of medically refractory epilepsy.{{Cite journal|last1=Mathews|first1=Marlon S.|last2=Linskey|first2=Mark E.|last3=Binder|first3=Devin K.|s2cid=6007475|date=29 February 2008|title=William P. van Wagenen and the first corpus callosotomies for epilepsy|journal=Journal of Neurosurgery|volume=108|issue=3|pages=608–613|doi=10.3171/JNS/2008/108/3/0608|pmid=18312112|issn=0022-3085}} The procedure was first performed in 1940 by William P. van Wagenen. In this procedure, the corpus callosum is cut through, in an effort to limit the spread of epileptic activity between the two halves of the brain.

Although the corpus callosum is the largest white matter tract connecting the hemispheres, some limited interhemispheric communication is still possible via the anterior and posterior commissures.{{Cite journal |last=Gazzaniga |first=M. S. |date=1 July 2000 |title=Cerebral specialization and interhemispheric communication: Does the corpus callosum enable the human condition? |url=https://academic.oup.com/brain/article-lookup/doi/10.1093/brain/123.7.1293 |journal=Brain |volume=123 |issue=7 |pages=1293–1326 |doi=10.1093/brain/123.7.1293|pmid=10869045 }} After the operation, however, the brain often struggles to send messages between hemispheres, which can lead to side effects such as speech irregularities, disconnection syndrome, and alien hand syndrome.

History

The first instances of corpus callosotomy were performed in the 1940s by William P. van Wagenen, who co-founded and served as president of the American Association of Neurological Surgeons. Attempting to treat epilepsy, van Wagenen studied and published the results of his surgeries, including the split-brain outcomes for patients. Most of the surgeries involved a partial division of the corpus callosum and resulted in improvements of seizure control in all patients. Wagenen's work preceded the 1981 Nobel Prize-winning research of Roger W. Sperry by two decades. Sperry studied patients who had undergone corpus callosotomy and detailed their resulting split-brain characteristics.{{cite journal |doi=10.3171/JNS/2008/108/3/0608 |title=William P. Van Wagenen and the first corpus callosotomies for epilepsy |year=2008 |last1=Mathews |first1=Marlon S. |last2=Linskey |first2=Mark E. |last3=Binder |first3=Devin K. |s2cid=6007475 |journal=Journal of Neurosurgery |volume=108 |issue=3 |pages=608–613 |pmid=18312112}}

Improvements to surgical techniques, along with refinements of the indications, have allowed van Wagenen's procedure to endure; corpus callosotomy is still commonly performed throughout the world.{{Cite journal |last1=Markosian |first1=Christopher |last2=Patel |first2=Saarang |last3=Kosach |first3=Sviatoslav |last4=Goodman |first4=Robert R. |last5=Tomycz |first5=Luke D. |date=1 March 2022 |title=Corpus Callosotomy in the Modern Era: Origins, Efficacy, Technical Variations, Complications, and Indications |url=https://www.sciencedirect.com/science/article/abs/pii/S1878875022000407#:~:text=Although%20still%20the%20treatment%20of,in%20patients%20who%20continue%20to |journal=World Neurosurgery |volume=159 |pages=146–155 |doi=10.1016/j.wneu.2022.01.037 |issn=1878-8750}} The surgery is a palliative treatment method for many forms of epilepsy, including atonic seizures, generalized seizures, and Lennox-Gastaut syndrome.{{cite journal| year= 2012 |title= Corpus Callosotomy: What is New and What is Relevant?|journal= World Neurosurgery|volume=77|issue=2|pages=304–305 |doi= 10.1016/j.wneu.2011.07.026| pmid=22120324| last1=Schaller |first1=Karl}} In a 2011 study of children with intractable epilepsy accompanied by attention deficit disorder, EEG showed an improvement to both seizures and attention impairments following corpus callosotomy.{{cite journal |last1=Yonekawa |first1=Takahiro |last2= Nakagawa |first2= Eiji| last3= Takeshita |first3= Eri |last4= Inoue |first4= Yuki |last5= Inagaki| first5= Masumi |last6= Kaga| first6= Makiko| last7=Sugai| first7= Kenji |last8= Sasaki |first8 =Masayuki |last9= Kaido |first9= Takanobu | last10= Takahashi| first10=Akio |last11= Otsuki| first11= Taisuke| display-authors= 3| year=2011|title=Effect of corpus callosotomy on attention deficit and behavioral problems in pediatric patients with intractable epilepsy| journal= Epilepsy & Behavior|volume=22|issue=4|pages=697–704| doi= 10.1016/j.yebeh.2011.08.027| pmid= 21978470 |s2cid=34733721 }}

Typical procedure

Prior to surgery, the patient's head must be partially or completely shaven. Once under general anesthesia, an incision will allow for a craniotomy to be performed. Then sectioning will occur between the two hemispheres of the brain. For a partial callosotomy, the anterior two-thirds of the corpus callosum are sectioned, and for a complete callosotomy, the posterior one-third is also sectioned. Afterward, the dura is closed and the portion of cranium is replaced. The scalp is then closed with sutures.{{cite book |editor1-first=Alexander G. |editor1-last=Reeves |editor2-first=David W. |editor2-last=Roberts |title=Epilepsy and the Corpus Callosum |volume=2 |location=New York |publisher=Plenum Press |year=1995 |isbn=978-0-306-45134-8}}{{page needed|date=July 2012}} Endoscopic corpus callosotomy has been employed with blood loss minimized during the surgical procedure.{{cite journal |vauthors = Sood S, Marupudi NI, Asano E, Haridas A, Ham SD |title = Endoscopic corpus callosotomy and hemispherotomy |journal = J Neurosurg Pediatr |volume = 16 |issue = 6 |pages = 681–6 |year = 2015 |pmid = 26407094 |doi = 10.3171/2015.5.PEDS1531 |doi-access = free }}

Indications

Corpus callosotomy is intended to treat patients who have epilepsy and the resultant chronic seizures. The diminished life expectancy associated with epilepsy has been documented by population-based studies in Europe. In the UK and Sweden, the relative mortality rate of epileptic patients (patients whose epilepsy was not under control from medical or other surgical therapies and who continued to have the disease) increased two- and threefold, respectively. In the vast majority of cases, corpus callosotomy abolishes instance of seizures in the patient.{{cite journal |doi=10.1002/1531-8249(199907)46:1<45::AID-ANA8>3.0.CO;2-I |title=Seizure control and mortality in epilepsy |year=1999 |last1=Sperling |first1=Michael R. |last2=Feldman |first2=Harold |last3=Kinman |first3=Judith |last4=Liporace |first4=Joyce D. |last5=O'Connor |first5=Michael J. |journal=Annals of Neurology |volume=46 |pages=45–50 |pmid=10401779 |issue=1|s2cid=20595932 |doi-access=free }}

=Contraindications=

Although it varies from patient to patient, a progressive neurological or medical disease might be an absolute or relative contraindication to corpus callosotomy. Intellectual disability is not a contraindication to corpus callosotomy. In a study of children with a severe intellectual disability, total callosotomy was performed with highly favorable results and insignificant morbidity.{{cite journal |doi=10.1016/j.yebeh.2008.04.020 |title=Corpus callosotomy |year=2008 |last1=Asadi-Pooya |first1=Ali A. |last2=Sharan |first2=Ashwini |last3=Nei |first3=Maromi |last4=Sperling |first4=Michael R. |journal=Epilepsy & Behavior |volume=13 |issue=2 |pmid=18539083 |pages=271–278|s2cid=19256444 }}

Neuroanatomical background

=Corpus callosum anatomy and function=

{{Main|Corpus callosum#Anatomy|l1=Anatomy of the corpus callosum}}

The corpus callosum is a fiber bundle of about 300 million fibers in the human brain that connects the two cerebral hemispheres. Its interhemispheric functions include the integration of perceptual, cognitive, learned, and volitional information.{{cite journal |doi=10.1016/j.neuroimage.2006.05.044 |title=Topography of the human corpus callosum revisited—Comprehensive fiber tractography using diffusion tensor magnetic resonance imaging |year=2006 |last1=Hofer |first1=Sabine |last2=Frahm |first2=Jens |journal=NeuroImage |volume=32 |issue=3 |pages=989–94 |pmid=16854598|s2cid=1164423 }}

=Role in epileptic seizures=

The role of the corpus callosum in epilepsy is the interhemispheric transmission of epileptiform discharges. These discharges are generally bilaterally synchronous in preoperative patients. In addition to disrupting this synchrony, corpus callosotomy decreases the frequency and amplitude of the epileptiform discharges, suggesting the transhemispheric facilitation of seizure mechanisms.{{cite journal |doi=10.1016/S1388-2457(03)00234-7 |title=Callosal role in generation of epileptiform discharges: Quantitative analysis of EEGs recorded in patients undergoing corpus callosotomy |year=2003 |last1=Matsuo |first1=Atsuko |last2=Ono |first2=Tomonori |last3=Baba |first3=Hiroshi |last4=Ono |first4=Kenji |journal=Clinical Neurophysiology |volume=114 |issue=11 |pages=2165–71 |pmid=14580615|s2cid=10604808 }}

Drawbacks

=Side effects=

The most prominent non-surgical complications of corpus callosotomy relate to speech irregularities. For some patients, sectioning may be followed by a brief spell of mutism. A long-term side effect may be an inability to engage in spontaneous speech. In addition, the resultant split-brain prevents some patients from following verbal commands that require the use of their non-dominant hand.{{cite journal |doi=10.1016/0920-1211(95)00052-6 |title=Corpus callosotomy: Seizure and psychosocial outcome a 39-month follow-up of 20 patients |year=1996 |last1=Andersen |first1=Birgit |last2=Árogvi-Hansen |first2=Bjarke |last3=Kruse-Larsen |first3=Christian |last4=Dam |first4=Mogens |journal=Epilepsy Research |volume=23 |pages=77–85 |pmid=8925805 |issue=1|s2cid=19538184 }}

Disconnection syndrome is another well-known side effect of the surgery.{{Cite journal |last1=Stigsdotter-Broman |first1=Lina |last2=Olsson |first2=Ingrid |last3=Flink |first3=Roland |last4=Rydenhag |first4=Bertil |last5=Malmgren |first5=Kristina |date=February 2014 |title=Long-term follow-up after callosotomy—A prospective, population based, observational study |journal=Epilepsia |volume=55 |issue=2 |pages=316–321 |doi=10.1111/epi.12488 |issn=0013-9580 |pmc=4165268 |pmid=24372273}} This occurs due to the brain's inability to transfer information between the hemispheres.{{Cite journal |last1=Lechevalier |first1=B. |last2=Andersson |first2=J. C. |last3=Morin |first3=P. |date=1 May 1977 |title=Hemispheric disconnection syndrome with a "crossed avoiding" reaction in a case of Marchiafava-Bignami disease. |url=https://jnnp.bmj.com/content/40/5/483.short |journal=Journal of Neurology, Neurosurgery & Psychiatry |volume=40 |issue=5 |pages=483–497 |doi=10.1136/jnnp.40.5.483 |issn=0022-3050 |pmid=894319|pmc=492724 }} One characteristic symptom is the "crossed-avoiding reaction", which is observed when one hemisphere does not respond to visual or sensory (e.g., touch, pressure, or pain) stimuli presented to the opposite side.

For instance, when an object is shown in the patient's right visual field, the left hemisphere (typically language-dominant) processes this information, allowing the patient to name the object easily. However, if the same object is shown in the left visual field, the right hemisphere perceives it, but the information does not transfer to the left (verbal) hemisphere.{{Cite journal |last1=de Haan |first1=Edward H. F. |last2=Corballis |first2=Paul M. |last3=Hillyard |first3=Steven A. |last4=Marzi |first4=Carlo A. |last5=Seth |first5=Anil |last6=Lamme |first6=Victor A. F. |last7=Volz |first7=Lukas |last8=Fabri |first8=Mara |last9=Schechter |first9=Elizabeth |last10=Bayne |first10=Tim |last11=Corballis |first11=Michael |last12=Pinto |first12=Yair |date=2020 |title=Split-Brain: What We Know Now and Why This Is Important for Understanding Consciousness |journal=Neuropsychology Review |volume=30 |issue=2 |pages=224–233 |doi=10.1007/s11065-020-09439-3 |issn=1040-7308 |pmc=7305066 |pmid=32399946}} Consequently, while the patient cannot verbally identify the object, they are still able to select it with their left hand.

Another complication is alien hand syndrome, in which the affected person's hand appears to take on a mind of its own.{{Cite journal|last1=Biran|first1=Iftah|last2=Giovannetti|first2=Tania|last3=Buxbaum|first3=Laurel|last4=Chatterjee|first4=Anjan|date=1 June 2006|title=The alien hand syndrome: What makes the alien hand alien?|journal=Cognitive Neuropsychology|volume=23|issue=4|pages=563–582|doi=10.1080/02643290500180282|issn=0264-3294|pmid=21049344|quote=The alien hand syndrome is a deeply puzzling phenomenon in which brain-damaged patients experience their limb performing seemingly purposeful acts without their intention. Furthermore, the limb may interfere with the actions of their normal limb.|citeseerx=10.1.1.537.6357|s2cid=15889976}} In one described incident, the patient grabbed their throat with their left hand and struggled to remove, as they had no control over it.{{Cite journal |last1=Hassan |first1=Anhar |last2=Josephs |first2=Keith A. |date=17 June 2016 |title=Alien Hand Syndrome |url=https://link.springer.com/article/10.1007/s11910-016-0676-z |journal=Current Neurology and Neuroscience Reports |volume=16 |issue=8 |page=73 |doi=10.1007/s11910-016-0676-z |pmid=27315251 |issn=1534-6293}}

Cognitive impairments may also be seen.{{cite journal |last1=Huang |first1=Xiaoqin |last2=Du |first2=Xiangnan |last3=Song |first3=Haiqing |last4=Zhang |first4=Qian |last5=Jia |first5=Jianping |last6=Xiao |first6=Tianyi |last7=Wu |first7=Jian |title=Cognitive impairments associated with corpus callosum infarction: a ten cases study |journal=International Journal of Clinical and Experimental Medicine |date=15 November 2015 |volume=8 |issue=11 |pages=21991–21998 |pmid=26885171 |pmc=4724017 }} Other symptoms may occur after the operation but generally go away on their own, such as scalp numbness, feeling tired or depressed, headaches, and difficulty speaking, remembering things, or finding words.{{Cite web|url=https://www.urmc.rochester.edu/neurosurgery/services/treatments/corpus-callosotomy.aspx|title=Corpus Callosotomy – Treatments – For Patients – UR Neurosurgery – University of Rochester Medical Center|website=urmc.rochester.edu}}

=Alternatives=

Epilepsy is also treated by a less invasive process called vagus nerve stimulation. This method utilizes an electrode implanted around the left vagus nerve within the carotid sheath in order to send electrical impulses to the nucleus of the solitary tract.{{cite journal |doi=10.1016/j.yebeh.2010.06.044 |title=Vagus nerve stimulation for drop attacks in a pediatric population |year=2010 |last1=Abd-El-Barr |first1=Muhammad M. |last2=Joseph |first2=Jacob R. |last3=Schultz |first3=Rebecca |last4=Edmonds |first4=Joseph L. |last5=Wilfong |first5=Angus A. |last6=Yoshor |first6=Daniel |journal=Epilepsy & Behavior |volume=19 |issue=3 |pmid=20800554 |pages=394–9|s2cid=13346234 }} However, corpus callosotomy has been proven to offer significantly better chances of seizure freedom compared with vagus nerve stimulation (58.0% versus 21.1% reduction in atonic seizures, respectively).{{cite journal|last1=Rolston|first1=John D.|last2=Englot|first2=Dario J.|last3=Wang|first3=Doris D.|last4=Garcia|first4=Paul A.|last5=Chang|first5=Edward F.|title=Corpus callosotomy versus vagus nerve stimulation for atonic seizures and drop attacks: A systematic review|journal=Epilepsy & Behavior|date=October 2015|volume=51|pages=13–17|doi=10.1016/j.yebeh.2015.06.001|pmid=26247311|pmc=5261864}}

References

External links

[https://web.archive.org/web/20050407105335/http://www.epilepsy.com/epilepsy/corpus_collostomy.html Details of procedure] at epilepsy.com
[http://www.surgeryencyclopedia.com/Ce-Fi/Corpus-Callosotomy.html Encyclopedia of Surgery: Corpus callosotomy]

Category:Neurosurgical procedures

Category:Epilepsy