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Open access

Utilization of three-dimensional fusion images with high-resolution computed tomography angiography for preoperative evaluation of microvascular decompression: patient series

Takamitsu Iwata, Koichi Hosomi, Naoki Tani, Hui Ming Khoo, Satoru Oshino, and Haruhiko Kishima

BACKGROUND

High-resolution computed tomography (CT), outfitted with a 0.25-mm detector, has superior capability for identifying microscopic anatomical structures compared to conventional CT. This study describes the use of high-resolution computed tomography angiography (CTA) for preoperative microvascular decompression (MVD) assessment and explores the potential effectiveness of three-dimensional (3D) image fusion with magnetic resonance imaging (MRI) by comparing it with traditional imaging methods.

OBSERVATIONS

Four patients who had undergone preoperative high-resolution CTA and MRI for MVD at Osaka University Hospital between December 2020 and March 2022 were included in this study. The 3D-reconstructed images and intraoperative findings were compared. One patient underwent conventional CTA, thus allowing for a comparison between high-resolution and conventional CTA in terms of radiation exposure and vascular delineation. Preoperative simulations reflected the intraoperative findings for all cases; small vessel compression of the nerve was identified preoperatively in two cases.

LESSONS

Compared with conventional CTA, high-resolution CTA showed superior vascular delineation with no significant change in radiation exposure. The use of high-resolution CTA with reconstructed 3D fusion images can help to simulate prior MVD. Knowing the location of the nerves and blood vessels can perioperatively guide neurosurgeons.

Open access

Management of a challenging dura-embedded anterior inferior cerebellar artery loop during a retrosigmoid hearing-preserving vestibular schwannoma resection: microsurgical technique and operative video. Illustrative case

Jaime L. Martínez Santos, Robert C. Sterner, and Mustafa K. Başkaya

BACKGROUND

Anatomical variants of the anterior inferior cerebellar artery (AICA), such as an anomalous “AICA loop” embedded in the dura and bone of the subarcuate fossa, increase the complexity and risk of vestibular schwannoma resections. Classically, osseous penetrating AICA loops are the most challenging to mobilize, as the dura must be dissected and the surrounding petrous bone must be drilled to mobilize the AICA away from the surgical corridor and out of harm.

OBSERVATIONS

The authors present a rare case of a dura-embedded, osseous-penetrating AICA loop encountered during a hearing-preserving retrosigmoid approach in which they demonstrate safe and efficient microdissection and mobilization of the AICA loop without having to drill the surrounding bone.

LESSONS

Although preoperative recognition of potentially dangerous AICA loops has been challenging, thin-sliced petrous bone computed tomography scanning and high-quality magnetic resonance imaging can be useful in preoperative diagnosis. Furthermore, this report suggests that a retrosigmoid approach is superior, as it allows early intradural recognition and proximal vascular control and facilitates more versatile mobilization of AICA loops.

Open access

A new strategy for treating drug-resistant focal aware seizures: thalamic specific nuclei deep brain stimulation. Illustrative case

Osvaldo Vilela-Filho, Hélio F. Silva-Filho, Lissa C. Goulart, Paulo C. Ragazzo, and Francisco M. Arruda

BACKGROUND

Focal aware seizures (FASs) are relatively common and frequently pharmaco-resistant. If the seizure onset zone (SOZ) is in eloquent cortical areas, making resective surgery risky and inadvisable, deep brain stimulation (DBS) of the anterior nucleus of the thalamus, which is efficacious in less than half of the cases, has been the main alternative. New targets should be searched to address this deficiency. The present study aims to determine if DBS of different thalamic specific nuclei can modulate the abnormal electrical activity of the SOZ located in their respective cortical projection areas. Herein, the authors present the first patient in an ongoing trial.

OBSERVATIONS

A 60-year-old female patient presented with 25-year history of pharmaco-resistant focal aware visual seizures frequently evolving to focal impaired awareness seizures. The SOZ was in the right occipital lobe (positron emission tomography-computed tomography/video electroencephalography). Magnetic resonance imaging was normal. She underwent ipsilateral lateral geniculate nucleus (LGN) DBS procedure. After a 24-month follow-up, seizure frequency decreased by 97%, improving quality of life and daily functioning without complications.

LESSONS

This is the first time the LGN has been targeted in humans. The results support the hypothesis that led to this study. This strategy represents a paradigm shift in the way of treating pharmaco-resistant FASs not amenable to resective surgery.

Open access

Removal of a flanged ventricular catheter: illustrative case

M. Benjamin Larkin, Tyler T. Lazaro, Howard L. Weiner, and William E. Whitehead

BACKGROUND

Flanged ventricular catheters were created in the 1970s to decrease shunt failure by preventing the holes at the catheter tip from contacting the choroid plexus. However, the flanges on the catheter frequently scarred within and tether to the choroid plexus, resulting in higher rates of intraventricular hemorrhage when removed. Today, flanged catheters are rarely encountered.

OBSERVATIONS

The authors describe an illustrative case of a 7-year-old girl recently adopted from another country with a history of myelomeningocele and shunted hydrocephalus. She had been treated with a flanged catheter at birth. She presented with a shunt infection, which required removal of the flanged catheter tethered to the choroid.

LESSONS

The authors illustrate the safe removal of a posterior-entry flanged ventricular catheter tethered to the choroid plexus using monopolar flexible electrocautery. The removal was monitored with a flexible endoscope inserted from an ipsilateral anterior burr hole and was followed by an endoscopic third ventriculostomy.

Open access

Intravascular ultrasound to aid in the diagnosis and revision of an intra-aortic pedicle screw: illustrative case

Landon D. Ehlers, Patrick J. Opperman, Jack E. Mordeson, Jonathan R. Thompson, and Daniel L. Surdell

BACKGROUND

Pedicle screw impingement on vessel walls has the potential for complications due to pulsatile effects and wall erosion. Artifacts from spinal instrumentation create difficulty in accurately evaluating this interface. The authors present the first case of intravascular ultrasound (IVUS) used to characterize a pedicle screw breach into the aortic lumen.

OBSERVATIONS

A 21-year-old female with surgically corrected scoliosis underwent computed tomography angiography (CTA) 3 years postoperatively, which revealed a pedicle screw within the thoracic aorta lumen. Metal artifact distorted the CTA images, which prompted the decision to use intraoperative IVUS. The IVUS confirmed the noninvasive imaging findings and guided final decisions regarding aortic endograft size and location during spine hardware revision.

LESSONS

For asymptomatic patients presenting with pedicle screws malpositioned in or near the aorta, treatment decisions revolve around the extent of vessel wall penetration. Intraluminal depth can be obscured by artifact on computed tomography or magnetic resonance imaging or inadequately evaluated by a transesophageal echocardiogram. In our intraoperative experience, IVUS confirmed the depth of vessel lumen violation by a single pedicle screw and no wall penetration by two additional screws of concern. This was useful in deciding on thoracic endovascular aortic repair graft size and landing zone and facilitated safe spinal instrumentation removal and revision.

Open access

Radiofrequency ablation during stereoelectroencephalography: from diagnostic tool to therapeutic intervention. Illustrative case

Demitre Serletis, Juan Bulacio, Justin Bingaman, Elham Abushanab, Stephen P. Harasimchuk, Richard Rammo, Silvia Neme-Mercante, and William Bingaman

BACKGROUND

Radiofrequency thermocoagulation (RFTC) during intracranial stereoelectroencephalography (sEEG) was first described as a safe technique for creating lesions of epileptic foci in 2004. Since that time, the method has been applied as a diagnostic and/or palliative intervention. Although widely practiced in European epilepsy surgical programs, the technique has not been popularized in the United States given the lack of Food and Drug Administration (FDA)–approved technologies permitting safe usage of in situ sEEG electrodes for this purpose.

OBSERVATIONS

The authors present a case report of a young female patient with refractory left neocortical temporal lobe epilepsy undergoing sEEG electrode implantation, who underwent sEEG-guided RFTC via a stereotactic temperature-sensing pallidotomy probe. Although used as a diagnostic step in her workup, the patient has remained seizure-free for nearly 18 months.

LESSONS

The use of in situ sEEG electrodes for RFTC remains limited in the United States. In this context, this case highlights a safe alternative and temporizing approach to performing diagnostic sEEG-guided RFTC, using a temperature-sensing pallidotomy probe to create small, precise stereotactic lesions. The authors caution careful consideration of this technique as a temporary work-around solution while also highlighting the rising need for new FDA-approved technologies for safe RFTC through in situ temperature-sensing sEEG electrodes.

Open access

Bilateral L5 pedicle fracture with L5–S1 spondylolisthesis after single-level L4–5 posterior lumbar interbody fusion: illustrative case

Toshiyuki Kitaori, Masato Ota, and Jiro Tamura

BACKGROUND

Single-level posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF) is a commonly performed surgical procedure for L4–5 isthmic spondylolisthesis. Postoperative L5 pedicle fracture with rapidly progressive spondylolisthesis at L5–S1 segment after L4–5 PLIF/TLIF is quite rare, and the etiology remains unclear. This report describes this rare complication and proposes a possible etiology focusing on the lumbosacral sagittal imbalance characterized by an anteriorly shifted lumbar loading axis.

OBSERVATIONS

The authors report a case complicated by L5 bilateral pedicle fractures and rapidly progressive spondylolisthesis at the L5–S1 segment very early after a single-level PLIF for L4–5 isthmic spondylolisthesis. Meyerding grade III anterolisthesis was observed at L5–S1 segment by 3 months after the initial surgery. Additional surgery was performed, and the fixation was extended to L4–ilium. Fracture healing was observed at 6 months postoperatively.

LESSONS

This complication may have been caused by abnormal local shear forces on the posterior neural arch of L5 vertebra and L5–S1 intervertebral disc, which were triggered by the fusion surgery for L4 shear-type spondylolisthesis. L4 sagittal vertical axis is considered a reasonable parameter representing lumbosacral sagittal imbalance with an anteriorly shifted loading axis and may be a candidate for the predictive parameters of this rare complication.

Open access

Deep brain stimulation in a pediatric dystonia patient with cochlear implants and mitochondrial disorder: novel application of a frameless stereotactic system and navigating the anesthesia choice and neurosurgical complexities. Illustrative case

Audrey Grossen, Helen H. Shi, Mallory Schenk, Amber Stocco, Justin Ramsey, Suneet Sahgal, Andrew K. Conner, and Virendra R. Desai

BACKGROUND

This report presents a case of medically refractory dystonia in a pediatric patient successfully treated with bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) while under general anesthesia by using microelectrode recordings (MERs) with intraoperative computed tomography (CT).

OBSERVATIONS

The patient was an 18-year-old female with primary dystonia secondary to mitochondrial Leigh syndrome. Her past medical history was significant for complex partial epilepsy and hearing loss treated with cochlear implants. Her cochlear implants precluded anatomical targeting via magnetic resonance imaging. Additionally, the patient could not tolerate awake surgery with MER. The decision was made to proceed with bilateral STN DBS with intraoperative CT with the patient under general anesthesia. The patient’s cochlear implants made standard frame placement difficult, so navigation was performed with the Nexframe system. Recordings were obtained with the patient under general anesthesia with ketamine, dexmedetomidine, and remifentanil. At the 3- and 6-month follow-ups, the patient demonstrated marked improvement in dystonia without neurological complications.

LESSONS

This is the first case of dystonia secondary to Leigh syndrome treated with DBS. Additionally, the authors describe the novel use of the Nexframe for DBS lead placement in a pediatric patient. This demonstrates that STN DBS with the use of MER and intraoperative CT can be a safe and effective method of treating dystonia in certain pediatric patients.

Open access

Open surgical ligation of a thoracic spinal epidural arteriovenous fistula causing thoracic myelopathy: illustrative case

Brandon R. W. Laing, Benjamin Best, John D. Nerva, and Aditya Vedantam

BACKGROUND

Spinal epidural arteriovenous fistulas (eAVFs) are rare spinal vascular malformations characterized by an abnormal connection from the paraspinal and paravertebral system to the epidural venous plexus. This contrasts with the more frequently seen spinal dural AVF, where the fistula is entirely intradural. Although endovascular repair is commonly performed for spinal eAVF, few cases require open surgical ligation.

OBSERVATIONS

The authors present a case of a 74-year-old male with progressive thoracic myelopathy secondary to a spinal eAVF. Thoracic magnetic resonance imaging (MRI) showed intramedullary T2 signal hyperintensity from T8 to T12. Spinal angiography revealed a primary arterial supply from the right T11 segmental artery and minor supply from the left T11 branches with drainage into the ventral epidural space. The patient underwent T11–12 laminectomy and complete right T11–12 facetectomy for ligation of the fistula with T11–L1 fusion. A postoperative spinal angiogram showed resolution of the fistula. Postoperatively, the patient’s myelopathy improved, and MRI showed a decrease in T2 cord intensity.

LESSONS

Spinal eAVFs are rare lesions that differ from the more commonly seen intradural dural AVF in that the abnormal connection is in the epidural space, and they are often associated with a dilated epidural venous pouch. Treatment involves endovascular, open surgical, or combined approaches.

Open access

Pediatric intraspinal arachnoid cyst: successful endoscopic fenestration. Illustrative case

Victoria Jane Horak, Med Jimson D. Jimenez, Melissa A. LoPresti, and Jeffrey S. Raskin

BACKGROUND

Intradural spinal arachnoid cysts (SACs) are a rare cause of spinal cord compression. Treatment is centered on decompression of the spinal cord via laminectomy or laminoplasty followed by resection or fenestration of the cyst. Although laminectomy or laminoplasty access may be needed to achieve the desired result, either procedure can be associated with more extensive surgical dissections and long-term spinal stability concerns, including postsurgical kyphosis.

OBSERVATIONS

The authors present a case of a cervical intradural SAC in a 4-month-old girl presenting with symptomatic compression. The patient was treated by laminotomy and endoscopic fenestration of the SAC with resolution of symptoms and no disease progression 10 months postoperatively, when the patient was 14 months old.

LESSONS

Microsurgical endoscopic fenestration of an intradural SAC can provide a less invasive means of treatment while avoiding the risks associated with more invasive approaches.