Operculoinsular cortectomy

Operculoinsular cortectomy

Operculoinsular cortectomy for refractory epilepsy is a relatively safe therapeutic option but temporary neurological deficits after surgery are frequent. A study of Bouthillier et al. highlighted the role of frontal/parietal opercula resections in postoperative complications. Corona radiata ischemic lesions are not clearly related to motor deficits. There were no obvious permanent neurological consequences of losing a part of an epileptic insula, including on the dominant side for language. A low complication rate can be achieved if the following conditions are met: 1) microsurgical technique is applied to spare cortical branches of the middle cerebral artery; 2) the resection of an opercula is done only if the opercula is part of the epileptic focus; and 3) the neurosurgeon involved has proper training and experience 1).


The goal of a study of Bouthillier et al. of the Sainte-Justine University Hospital CenterMontrealQuebecCanada, was to document seizure control outcome after operculoinsular cortectomy in a group of patients investigated and treated by an epilepsy team with 20 years of experience with this specific technique.

Clinical, imaging, surgical, and seizure control outcome data of all patients who underwent surgery for refractory epilepsy requiring an operculoinsular cortectomy were retrospectively reviewed. Tumors and progressive encephalitis cases were excluded. Descriptive and uni- and multivariate analyses were done to determine seizure control outcome and predictors.

Forty-three patients with 44 operculoinsular cortectomies were studied. Kaplan-Meier estimates of complete seizure freedom (first seizure recurrence excluding auras) for years 0.5, 1, 2, and 5 were 70.2%, 70.2%, 65.0%, and 65.0%, respectively. With patients with more than 1 year of follow-up, seizure control outcome Engel class I was achieved in 76.9% (mean follow-up duration 5.8 years; range 1.25-20 years). With multivariate analysis, unfavorable seizure outcome predictors were frontal lobe-like seizure semiology, shorter duration of epilepsy, and the use of intracranial electrodes for invasive monitoring. Suspected causes of recurrent seizures were sparing of the language cortex part of the focus, subtotal resection of cortical dysplasia/polymicrogyria, bilateral epilepsy, and residual epileptic cortex with normal preoperative MRI studies (insula, frontal lobe, posterior parieto-temporal, orbitofrontal).

The surgical treatment of operculoinsular refractory epilepsy is as effective as epilepsy surgery in other brain areas. These patients should be referred to centers with appropriate experience. A frontal lobe-like seizure semiology should command more sampling with invasive monitoring. Recordings with intracranial electrodes are not always required if the noninvasive investigation is conclusive. The complete resection of the epileptic zone is crucial to achieving good seizure control outcome 2).


In 2017 Bouthillier et al. published twenty-five patients underwent an epilepsy surgery requiring an operculoinsular cortectomy: mean age at surgery was 35 y (9-51), mean duration of epilepsy was 19 y (5-36), 14 were female, and mean duration of follow-up was 4.7 y (1-16). Magnetic resonance imaging of the operculoinsular area was normal or revealed questionable nonspecific findings in 72% of cases. Investigation with intracranial EEG electrodes was done in 17 patients. Surgery was performed on the dominant side for language in 7 patients. An opercular resection was performed in all but 2 patients who only had an insulectomy. Engel class I seizure control was achieved in 80% of patients. Postoperative neurological deficits (paresis, dysphasia, alteration of taste, smell, hearing, pain, and thermal perceptions) were frequent (75%) but always transient except for 1 patient with persistent mild alteration of thermal and pain perception. 3).

References

1)

Bouthillier A, Weil AG, Martineau L, Létourneau-Guillon L, Nguyen DK. Operculoinsular cortectomy for refractory epilepsy. Part 2: Is it safe? J Neurosurg. 2019 Sep 20:1-11. doi: 10.3171/2019.6.JNS191126. [Epub ahead of print] PubMed PMID: 31597116.
2)

Bouthillier A, Weil AG, Martineau L, Létourneau-Guillon L, Nguyen DK. Operculoinsular cortectomy for refractory epilepsy. Part 1: Is it effective? J Neurosurg. 2019 Sep 20:1-10. doi: 10.3171/2019.4.JNS1912. [Epub ahead of print] PubMed PMID: 31629321.
3)

Bouthillier A, Nguyen DK. Epilepsy Surgeries Requiring an Operculoinsular Cortectomy: Operative Technique and Results. Neurosurgery. 2017 Oct 1;81(4):602-612. doi: 10.1093/neuros/nyx080. PubMed PMID: 28419327.

Miyazaki syndrome

Miyazaki syndrome

Miyazaki syndrome is a cervical myelopathy or cervical radiculopathy caused by cervical epidural venous congestion, due to shunt overdrainage. The complex pathophysiology includes CSF pressure-changes consistent with the Monro-Kellie hypothesis and a non-functional Starling resistor, leading to spinal epidural venous plexus enlargement and dilation. This venous congestion may be significant enough to exert compression on the spinal cord or nerve roots. The typical clinical and imaging findings together with a history of ventricular CSF shunting may establish the diagnosis, proven by a successful treatment. The aim of treatment is the abrogation of CSF over-drainage. The eligible interventions may be the followings: the increase of the opening-pressure of the valve system by the insertion of a new programmable valve if necessary, closing or removing the shunt.


In 1997 Miyazaki et al. described a case of intracranial hypotension syndrome due to overdrainage of cerebrospinal fluid presented with hearing loss afterventriculoperitoneal shunting procedure. A 69-year-old man suffering from subarachnoid hemorrhage presented with an angiogram showing two aneurysms, one of the right internal carotid artery and one of the middle cerebral artery. Neck clipping was performed. One month later, he developed normal pressure hydrocephalus (NPH), which was treated by ventriculoperitoneal shunting procedure using low pressure Pudenz valve system. Trias of NPH were improved by insertion of shunt system. However, he complained of hearing loss which was worsened by upright position and improved by lying down. Such kinds of phenomenon were demonstrated by audiogram showing that the transitory decrease of hearing and electrocochleography showing the elongation of N1 latency at upright position. These data suggested that his hearing loss was caused by inner ear or auditory nerve lesion. After the shunt system was replaced into the antisiphon device, his hearing disturbance improved. Axial computed tomography of bone window at the level of orbitomeatal line demonstrated widely perilymphatic duct on both sides. This finding suggested that the fluctuation of intracranial pressure was easily transmitted into the cochlear through the widened perilymphatic duct, resulting in hearing disturbance 1).


Várallyay et al. want to call attention to this rare iatrogenic condition with potentially severe consequences.

They performed a systematic literature-review and presented ther five cases.

Once recognized in time, Miyazaki syndrome can be well taken care of.

Patients with chronic ventricular shunt need monitoring for CSF over-drainage to recognise potential complications such as cervical myelopathy or radiculopathy 2).


In 2018 a 33-year-old patient had undergone placement of a ventriculoperitoneal shunt with a pressure-adjustable valve for communicating hydrocephalus years before presenting to our department with the complaints of constant headache and unsteady gait. On the basis of the clinical picture and her history, plain and contrast-enhanced cranial and whole spine magnetic resonance imaging and magnetic resonance angiography examinations were performed, with the scans revealing signs indicative of cerebrospinal fluid hypotension typical of Miyazaki syndrome 3).


In 2015 Caruso et al. reported one case 4).

References

1)

Miyazaki Y, Tomii M, Sawauchi S, Ikeuchi S, Yuki K, Abe T. [A case of hearing loss caused by overdrainage of cerebrospinal fluid after ventriculo-peritoneal shunting procedure]. No Shinkei Geka. 1997 Apr;25(4):367-71. Japanese. PubMed PMID: 9125722.
2)

Várallyay P, Nagy Z, Szűcs A, Czigléczki G, Markia B, Nagy G, Osztie É, Vajda J, Vitanovics D. Miyazaki syndrome: Cervical myelo/radiculopathy caused by overshunting. A systematic review. Clin Neurol Neurosurg. 2019 Sep 24;186:105531. doi: 10.1016/j.clineuro.2019.105531. [Epub ahead of print] PubMed PMID: 31622897.
3)

Kovács A, Németh T, Csomor A, Novák T, Kövér F, Vörös E. Miyazaki Syndrome due to Ventriculoperitoneal Shunt Treatment. World Neurosurg. 2018 Aug;116:29-34. doi: 10.1016/j.wneu.2018.05.032. Epub 2018 May 31. PubMed PMID: 29775766.
4)

Caruso R, Wierzbicki V, Marrocco L, Pesce A, Piccione E. A Poorly Known Cerebrospinal Fluid Shunt Complication: Miyazaki Syndrome. World Neurosurg. 2015 Sep;84(3):834-8. doi: 10.1016/j.wneu.2015.04.030. Epub 2015 Apr 23. PubMed PMID: 25913430.
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