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Open access

Intraoperative application of indocyanine green and temporary venous occlusion test to assess collateral flow during microvascular decompression for venous-related trigeminal neuralgia: illustrative case

Kentaro Fujimoto, Yosuke Akamatsu, Yasumasa Nishikawa, and Kuniaki Ogasawara

BACKGROUND

In microvascular decompression (MVD) for vein-related trigeminal neuralgia (TN), determining whether transection of the offending vein is safe can be challenging. Here, the authors present a case of vein-related TN successfully treated by sacrificing the offending vein on the basis of findings from indocyanine green (ICG) video angiography and a temporary venous occlusion test to assess the collateral flow of the offending vessel.

OBSERVATIONS

A 43-year-old man presented with TN, which had failed to respond to previous medical therapy. Gadolinium-enhanced magnetic resonance imaging (MRI) revealed that the transverse or superior petrosal vein was the offending vein. The patient underwent MVD. Because the transposition of the offending vein was anatomically challenging, a temporary vein occlusion test was performed using ICG video angiography. During and after temporary occlusion, bidirectional flow in the offending vein was observed, suggesting collateral flow even after vein occlusion. On the basis of these findings, the offending vein was transected, resulting in relief from pain without any complications. Postoperative MRI revealed no new lesions in the brainstem or the cerebellar hemisphere. The patient has been free from neuralgia for 6 months.

LESSONS

The temporary vein occlusion test under ICG video angiography was useful for evaluating collateral flow in the offending vein in TN.

Open access

Cervicothoracic ventral-dorsal rhizotomy for bilateral upper-extremity hypertonia in cerebral palsy: illustrative case

Ryan Kelly, Hanna R Kemeny, Sunny Abdelmageed, Robin Trierweiler, Tim Krater, Melissa A LoPresti, and Jeffrey S Raskin

BACKGROUND

Management of medically refractory limb-specific hypertonia is challenging. Neurosurgical options include deep brain stimulation, intrathecal baclofen, thalamotomy, pallidotomy, or rhizotomy. Cervical dorsal rhizotomy has been successful in the treatment of upper-extremity spasticity. Cervical ventral and cervical ventral-dorsal rhizotomy (VDR) has been used in the treatment or torticollis and traumatic hypertonia; however, the use of cervicothoracic VDR for the treatment of upper-extremity mixed hypertonia is not well described.

OBSERVATIONS

A 9-year-old girl with severe quadriplegic mixed hypertonia secondary to cerebral palsy (CP) underwent cervicothoracic VDR. Modified Ashworth Scale scores, provision of caregiving, and examination improved. Treatment was well tolerated.

LESSONS

Cervicothoracic VDR can afford symptomatic and quality of life improvement in patients with medically refractory limb hypertonia. Intraoperative positioning and nuances in surgical techniques are particularly important based on spinal cord position as modified by scoliosis. Here, the first successful use of cervicothoracic VDR for the treatment of medically refractory upper-limb hypertonia in a pediatric patient with CP is described.

Open access

Quantitative susceptibility mapping and a nonlinearly transformed atlas for targeting the ventral intermediate nucleus of the thalamus in a patient with tremor and thalamic hypertrophy: illustrative case

Kazuya Ohtsuki, Masahiro Sawada, Wataru Yoshizaki, Takayoshi Ishimori, Nobukatsu Sawamoto, Yasutaka Fushimi, and Hiroki Toda

BACKGROUND

The ventral intermediate nucleus (Vim) of the thalamus is a surgical target for treating various types of tremor. Because it is difficult to visualize the Vim using standard magnetic resonance imaging, the structure is usually targeted based on the anterior and posterior commissures. This standard targeting method is practical in most patients but not in those with thalamic asymmetry. The authors examined the usefulness of quantitative susceptibility mapping (QSM) and transformed Vim atlas images to estimate the Vim localization in a patient with tremor and significant thalamic hypertrophy.

OBSERVATIONS

A 51-year-old right-handed female had experienced a predominant left-hand action tremor for 6 years. Magnetic resonance imaging showed significant hypertrophy of the right thalamus and caudal shift of the thalamic ventral border. The authors referred to the QSM images to localize the decreased susceptibility area within the lateral ventral thalamic nuclei to target the Vim. In addition, the nonlinearly transformed Vim atlas images complemented the imaging-based targeting. The radiofrequency thalamotomy at the modified Vim target relieved the tremor completely.

LESSONS

A combination of QSM and nonlinear transformation of the thalamic atlas can be helpful in the targeting method of the Vim for tremor patients with thalamic asymmetry.

Open access

Optimization of direct cortical stimulation using tibial versus median nerve sensory mapping during midline brain tumor resection: illustrative case

Denmark Mugutso, Charles Warnecke, Lee Eric Tessler, Christopher J Pace, and Marat V Avshalumov

BACKGROUND

During brain tumor resection, neurophysiological mapping and monitoring help surgeons locate, characterize, and functionally assess eloquent brain areas in real time. The selection of mapping and monitoring targets has implications for successful surgery. Here, the authors compare direct cortical stimulation (DCS) as suggested by median nerve (MN) with posterior tibial nerve (PTN) cortical sensory mapping (SM) during mesial lesion resection.

OBSERVATIONS

Recordings from a 6-contact cortical strip served to generate an MN and a PTN sensory map, which indicated the strip was anterior to the central sulcus. Responses exhibited an amplitude gradient with no phase reversal (PR). DCS, elicited through a stimulus probe or contact(s) of the strip, yielded larger responses from the corresponding sensory mapped limb; that is, PTN SM resulted in larger lower limb muscle responses than those suggested by MN SM.

LESSONS

SM of the MN and PTN is effective for localizing eloquent cortical areas wherein the PTN is favored in surgery for mesial cortical tumors. The recorded amplitude of the cortical somatosensory evoked potential is a valuable criterion for defining the optimal location for DCS, despite an absent PR. The pathway at risk dictates the specifics of SM, which subsequently defines the optimal location for DCS.

Open access

Vagus nerve stimulation for enhanced stroke recovery after intracerebral hemorrhage: illustrative case

Daniel D Cummins, Roshini Kalagara, Margaret H Downes, Hyun Joo Park, Jenna Tosto-Mancuso, David Putrino, Fedor E Panov, and Christopher P Kellner

BACKGROUND

Randomized controlled trial (RCT) evidence has revealed the efficacy of vagus nerve stimulation (VNS) paired with rehabilitation therapy, over therapy alone, for upper-limb functional recovery after ischemic stroke. However, this technique has not yet been described for the recovery of chronic motor deficits after hemorrhagic stroke.

OBSERVATIONS

Three years after left putaminal intracerebral hemorrhagic stroke with chronic upper-limb functional deficits, a patient was treated with VNS for enhanced stroke recovery. VNS was paired with 6 weeks of in-clinic physical therapy, resulting in upper-limb functional improvement of 14 points on the Fugl-Meyer Assessment Upper Extremity (FMA-UE) index for stroke recovery (maximum score of 66 equating to normal function). This improvement was more than 1 standard deviation above the improvement documented in the first successful RCT of VNS paired with therapy for ischemic stroke (5.0 ± 4.4 improvement on FMA-UE).

LESSONS

VNS is a promising therapy for enhanced recovery after hemorrhagic stroke and may offer greater improvement in function compared to that after ischemic stroke. Improvement in function can occur years after the time of intracerebral hemorrhage.

Open access

Microvascular decompression for developmental venous anomaly causing hemifacial spasm: illustrative case

Margaret Tugend and Raymond F Sekula Jr.

BACKGROUND

Developmental venous anomaly (DVA) is a rare cause of hemifacial spasm (HFS). The treatment of HFS caused by a DVA varies in the literature and includes medication management, botulinum toxin injections, and microvascular decompression (MVD).

OBSERVATIONS

A 64-year-old woman presented with right-sided HFS. Preoperative magnetic resonance imaging showed a DVA in the right inferior pons, with an enlarged segment compressing the facial nerve at its root detachment point prior to drainage into the superior petrosal sinus. MVD was performed, and the facial nerve was decompressed without sacrifice of the vein. Immediately following the procedure, the patient had significantly reduced spasms. The patient became spasm-free 3 months after MVD and maintained spasm freedom for 3 months. Six months after MVD, the patient had a partial return of spasms. At 8 months, the patient continued to have reduced and intermittent spasms in the right orbicularis oculi muscle.

LESSONS

MVD for HFS caused by a DVA is a safe procedure and can be effective at reducing spasm frequency and severity.

Open access

Bilateral and asymmetrical localization of language function identified by the superselective infusion of propofol in an epilepsy patient with a mild malformation of cortical development: illustrative case

Mayuko Otomo, Shin-ichiro Osawa, Kyoko Suzuki, Kazuo Kakinuma, Kazushi Ukishiro, Hiroyoshi Suzuki, Kuniyasu Niizuma, Norio Narita, Nobukazu Nakasato, and Teiji Tominaga

BACKGROUND

Atypical localization of language function can result in unexpected postsurgical deficits after cortical resection, but it is difficult to predict the risk in the presurgical evaluation. The authors experienced a rare case of the bilateral and independent existence of different components of language function identified by segmented evaluation of anatomical anterior and posterior language areas using the superselective infusion of propofol.

OBSERVATIONS

A 32-year-old right-handed female presented with drug-resistant epilepsy. Comprehensive epilepsy evaluation suggested that the epileptic foci involved the whole left frontal lobe but provided less evidence of structural abnormality. To estimate the extent of functional deterioration likely to be caused by an extended left frontal lobectomy, the authors evaluated segmented cortical function in the ipsi- and contralateral hemispheres by the superselective infusion of propofol into the branches of the intracranial artery. The results revealed bilateral and asymmetrical localization of language function because the patient presented with different components of aphasia in each hemisphere. Based on the authors’ assessment of her functional tolerance, an extended left frontal lobectomy was performed and resulted in neurological deficits within the anticipated range.

LESSONS

An accurate understanding of the correlations between vascular and functional anatomy and the highly specific evaluation of language function provides more advanced presurgical assessment, allowing more tailored planning of cortical resection.

Open access

Spinal cord stimulation for chronic pain treatment following sacral chordoma resection: illustrative case

Khaled M Taghlabi, Taimur Hassan, Isuru A Somawardana, Sibi Rajendran, Ahmed Doomi, Lokeshwar S Bhenderu, Jesus G Cruz-Garza, and Amir H Faraji

BACKGROUND

Cancer-related or postoperative pain can occur following sacral chordoma resection. Despite a lack of current recommendations for cancer pain treatment, spinal cord stimulation (SCS) has demonstrated effectiveness in addressing cancer-related pain.

OBSERVATIONS

A 76-year-old female with a sacral chordoma underwent anterior osteotomies and partial en bloc sacrectomy. She subsequently presented with chronic pain affecting both buttocks and posterior thighs and legs, significantly impeding her daily activities. She underwent a staged epidural SCS paddle trial and permanent system placement using intraoperative neuromonitoring. The utilization of percutaneous leads was not viable because of her history of spinal fluid leakage, multiple lumbosacral surgeries, and previous complex plastic surgery closure. The patient reported a 62.5% improvement in her lower-extremity pain per the modified Quadruple Visual Analog Scale and a 50% improvement in the modified Pain and Sleep Questionnaire 3-item index during the SCS trial. Following permanent SCS system placement and removal of her externalized lead extenders, she had an uncomplicated postoperative course and reported notable improvements in her pain symptoms.

LESSONS

This case provides a compelling illustration of the successful treatment of chronic pain using SCS following radical sacral chordoma resection. Surgeons may consider this treatment approach in patients presenting with refractory pain following spinal tumor resection.

Open access

Stereoelectroencephalography in the setting of a previously implanted responsive neural stimulation device: illustrative case

Dorian M Kusyk, Nicholas Blaney, Timothy Quezada, and Alexander C Whiting

BACKGROUND

Responsive neural stimulation (RNS) is a relatively novel procedure for drug-resistant epilepsy, which involves implantation of a device into the skull and brain. As more devices are implanted, there may be an increasing need to perform intracranial electrocorticography in implant patients with persistent seizures. Given the device location, imaging difficulties with implanted devices, and other technical hurdles, stereoelectroencephalography (SEEG) could be especially challenging. The authors describe the first reported SEEG investigation in a patient with an RNS device, highlighting the technical challenges and clinical data ascertained.

OBSERVATIONS

A 41-year-old male with drug-resistant epilepsy presented several years after a local surgeon had placed an RNS device with two electrodes in the bilateral parieto-occipital lobes. Because of inadequate seizure control, the patient was offered a repeat SEEG investigation to characterize his epilepsy better. Although more technically challenging than a traditional SEEG implantation, the SEEG investigation was successfully performed, which led to a confirmation of bilateral hippocampal seizure onset. The patient underwent repositioning of his RNS leads with a significant decrease in his seizure frequency.

LESSONS

Concurrent implantation of SEEG electrodes in a functioning RNS device can be safely performed and can augment our understanding of a patient’s seizures.

Open access

Hemifacial spasm caused by multiple vascular attachments due to remote compression effects of a dermoid cyst in the cerebellar hemisphere: illustrative case

Kento Hirayama, Takafumi Tanei, Takenori Kato, Toshinori Hasegawa, Eiji Ito, Yusuke Nishimura, and Ryuta Saito

BACKGROUND

Dermoid cysts located laterally in the posterior fossa are rare. The authors report the case of a dermoid cyst in the cerebellar hemisphere presenting with hemifacial spasm (HFS) caused by multiple vascular attachments due to remote compression effects.

OBSERVATIONS

A 48-year-old man presented with left HFS. Computed tomography showed a mass lesion in the left cerebellar hemisphere with calcification and erosion of skull bone. Magnetic resonance imaging showed no contrast enhancement of the lesion and a dural defect. The lesion compressed the brainstem and cerebellopontine cistern, but no vascular attachments to the facial nerve were seen. Tumor removal and microvascular decompression were performed. The lesion was composed of soft tissue containing oil-like liquid and hairs, and the border of the cerebellar arachnoid was clear. There were multiple vascular attachments to the root exit zone, facial nerve, and brainstem. After displacing these arteries, the intraoperative abnormal muscle response disappeared. Histopathological findings showed stratified squamous epithelium, keratin flakes, calcifications, and hairs. The HFS disappeared completely and has remained absent for 27 months.

LESSONS

The dermoid cyst originating from occipital bone compressed the cerebellar hemisphere, displacing multiple vessels and leading to HFS. Tumor removal and the removal of all vascular factors can completely resolve HFS.