Two reports of iatrogenic pseudoaneurysms intraoperatively induced by an ultrasonic surgical aspirator: A rare intraoperative complication.

Background: The ultrasonic surgical aspirator is widely used in intracranial tumor resection as this instrument is considered safe. The advantage of an ultrasonic surgical aspirator is that it does not damage vessels or nerves close to the tumor. Therefore, limited information exists regarding intraoperative arterial injury by the ultrasonic surgical aspirator. Case Description: We report two cases. The first case was a 30-year-old woman who underwent surgery for a recurrent craniopharyngioma, and the second was a 50-year-old man who underwent surgery for a meningioma. A craniopharyngioma encased the basilar artery in the former case, and the superior cerebellar artery was encased by a meningioma in the latter. An ultrasonic surgical aspirator was used to resect the tumors in two cases. During surgery, the arteries involved in the tumors were unintentionally injured using an ultrasonic surgical aspirator. Intraoperative hemostasis was achieved for the bleeding from the injured arteries. However, postoperative digital cerebral angiography revealed pseudoaneurysms in the injured arteries. A subarachnoid hemorrhage occurred in the first case. The pseudoaneurysms were managed using endovascular embolization. Conclusion: Intraoperative arterial injury can occur with the application of an ultrasonic surgical aspirator. Neurosurgeons should be cautious when using ultrasonic surgical aspirators to avoid damaging the arteries involved with the tumor.

Exoscopic microvascular decompression for hemifacial spasm and trigeminal neuralgia.

The 4K 3D exoscope system is becoming increasingly used in neurosurgery. Its 3D ultra-high-definition image is valuable in identifying and dissecting the delicate neural and vascular structures during microvascular decompression. In this video, the authors describe several nuances and details to perform the exoscopic microvascular decompression, including the exoscope layout and the modified supine position. Several illustrative case presentations highlight the benefits of exoscopic surgery. The authors' exoscopic microvascular decompression series of 159 patients showed noninferior surgical outcomes compared to the operative microscope with no significant increase in surgical risk. In conclusion, an exoscope can be a practical alternative to performing microvascular decompression. The video can be found here: https://stream.cadmore.media/r10.3171/2023.10.FOCVID23122.

[Microvascular Decompression for Trigeminal Neuralgia Due to Venous Compression].

In microvascular decompression surgery for trigeminal neuralgia, the veins are essential as an anatomical frame for the microsurgical approach and as an offending vessel to compress the trigeminal nerve. Thorough arachnoid dissection of the superior petrosal vein and its tributaries provides surgical corridors to the trigeminal nerve root and enables the mobilization of the bridging, brainstem, and deep cerebellar veins. It is necessary to protect the trigeminal nerve by coagulating and cutting the offending vein. We reviewed the clinical features of trigeminal neuralgia caused by venous decompression and its outcomes after microvascular decompression. Among patients with trigeminal neuralgia, 4%-14% have sole venous compression. Atypical or type 2 trigeminal neuralgia may occur in 60%-80% of cases of sole venous compression. Three-dimensional MR cisternography and CT venography can help in detecting the offending vein. The transverse pontine vein is the common offending vein. The surgical cure and recurrence rates of trigeminal neuralgia with venous compression are 64%-75% and 23%, respectively. Sole venous compression is a unique form of trigeminal neuralgia. Its clinical characteristics differ from those of trigeminal neuralgia caused by arterial compression. Surgical procedures to resolve venous compression include nuances in safely handling venous structures.

Risk of Bone Wax Migration During Retrosigmoid Craniotomy for Microvascular Decompression: Case-Control Study.

BACKGROUND AND OBJECTIVES: Bone wax is a flexible hemostatic agent commonly used for surgery in the posterior cranial fossa to control bleeding from the mastoid emissary vein. A large amount of bone wax can migrate into the sigmoid sinus through the mastoid emissary canal (MEC). We aimed to identify clinical factors related to intraoperative bone wax migration through the MEC during microvascular decompression (MVD) surgery, which may result in sigmoid sinus thrombosis. METHODS: We retrospectively collected the clinical data of patients with trigeminal neuralgia, hemifacial spasm, or trigeminal neuralgia accompanied by painful tic convulsif who underwent MVD. Basic information and the residual width and length (from the bone surface to the sigmoid sinus) of the MEC on computed tomography images were collected. We compared the collected clinical data between 2 groups of cases with and without intraoperative bone wax migration in the sigmoid sinus. RESULTS: Fifty-four cases with intraoperative bone wax migration and 187 patients without migration were enrolled. The t -test revealed significant differences in the width and length of the MEC ( P = .013 and P = .003, respectively). These variables were identified as significant factors in predicting intraoperative bone wax migration using multivariate logistic regression analysis. CONCLUSION: The large size of the MEC may be related to intraoperative bone wax migration into the sigmoid sinus in MVD. Neurosurgeons should be aware of these risks. Bone wax should be applied appropriately and hemostasis should be considered to control bleeding from the mastoid emissary vein in patients with a large MEC.

Functionality and Usability of the Exoscope in Microvascular Decompression for Hemifacial Spasm and Trigeminal Neuralgia.

BACKGROUND: Studies on the functionality and usability of the exoscope in neurosurgical procedures against surgical microscopes (SMs) are limited. This study aimed to examine the functionality and usability of the exoscope during microvascular decompression (MVD) surgery. METHODS: Seven neurosurgeons evaluated the usefulness of a 4 K, 3-dimension digital exoscope in MVD by answering a questionnaire. The questionnaire inquired about the functionality and usability of the exoscope by utilizing a visual analog scale (VAS; 1-10). A score of 5 on VAS was equivalent to the corresponding quality of the SM. The learning effect of the exoscope was evaluated using mean VAS scores in the first and last 3 cases for each neurosurgeon. RESULTS: The functionality of the exoscope in MVD was superior to that in SM (P < 0.001). In the last 3 surgeries, the mean VAS scores of the exoscope were excellent in terms of ease of arm handling, exchange of surgical instruments, ease of surgical procedure, and intraoperative physical stress. The mean VAS scores of the exoscope in intraoperative asthenopia were significantly higher than those of the SM (P < 0.001). No statistical significance was found in operation time, discharge outcome, and 1-year post-surgery outcome between MVD performed using the exoscope and SM. CONCLUSIONS: Neurosurgeons may experience reduced stress levels during MVD when using the exoscope. As the outcome of MVD using the exoscope did not demonstrate a statistical difference compared with MVD using the SM, the exoscope may prove to be a useful tool for performing MVD.

Low back pain improvement after cervical laminoplasty in patients without tandem lumbar stenosis.

PURPOSE: This study aimed to demonstrate the impact of lumbar spinal stenosis (LSS) on LBP after cervical laminoplasty for cervical spinal stenosis by analyzing the clinical characteristics and surgical outcomes. METHODS: This retrospective cohort study analyzed 56 consecutive patients with cervical spinal stenosis who underwent cervical laminoplasty. Data on age, sex, Japanese Orthopaedic Association (JOA) scores, JOA Back Pain Evaluation Questionnaire (BPEQ), and visual analog scale (VAS) were collected. The patients with VAS for LBP ≥ 30 or more were included and divided into two groups: without LSS [LSS (-)]or with LSS [LSS (+)]. Preoperative clinical characteristics and postoperative changes were compared between the groups. RESULTS: Preoperative VAS for LBP were 50.7 ± 16.2 mm and 59.8 ± 19.5 mm in the LSS (+) and LSS (-), respectively (p = 0.09). Patients in the LSS (-) were younger (57.6 ± 11.2 vs. 70.7 ± 8.6, p < 0.001) and showed significantly milder preoperative lumbar symptoms in terms of JOA and BPEQ. Patients in the LSS (-) group showed more postoperative changes in low back pain (18.3 ± 26.4 vs. - 8.3 ± 37.6, p = 0.005) and lumbar function (10.8 ± 25.7 vs. - 2.0 ± 22.5, p = 0.04) at BPEQ, and higher recovery in terms of VAS of LBP (23.0 ± 23.8 mm vs. 5.3 ± 25.9 mm, p = 0.008) and buttocks and low limbs (12.5 ± 35.0 mm vs. - 4.3 ± 24.4 mm, p = 0.029). Nine patients in the LSS (+) group underwent lumbar surgery at 12.8 ± 8.5 months after cervical laminoplasty. CONCLUSION: LBP improved after cervical laminoplasty in patients without lumbar stenosis.

Intramedullary feeder aneurysm of a cervical epidural arteriovenous fistula causing myelopathy: a case report and literature review.

While a craniocervical junction (CCJ) epidural arteriovenous fistula (EDAVF) may present with hemorrhagic myelopathy from an associated feeder aneurysm on rare occasions, non-hemorrhagic myelopathy from such an aneurysm remains unreported. A woman in her late sixties presented with cervical myelopathy due to a non-hemorrhagic intramedullary aneurysm associated with CCJ-EDAVF. The intramedullary aneurysm originated from the spinal pial artery supplied by the anterior spinal artery. Direct surgical fistula coagulation and feeder obliteration resulted in the disappearance of the aneurysm and myelopathy improvement. This report illustrates the first case of a non-hemorrhagic intramedullary aneurysm associated with CCJ-EDAVF successfully treated with direct surgery.

Recovery from hemidiaphragmatic paralysis with improved respiratory function following cervical laminoplasty and foraminotomy: illustrative case.

BACKGROUND: Hemidiaphragmatic paralysis can occasionally be caused by cervical canal and foraminal stenosis. Rarely is the effect of surgical decompression on hemidiaphragmatic paralyzed patient respiratory function recorded. This report details a case of postoperative respiratory function restoration in a patient with cervical spondylosis-related hemidiaphragmatic paralysis. OBSERVATIONS: A 77-year-old woman suffered hemidiaphragmatic paralysis caused by cervical canal and foraminal stenosis. The phrenic nerve palsy was thought to be caused by compression of the cervical spinal cord and its nerve root. The patient received a C3 laminectomy, a C4-6 laminoplasty, and a left C3-4 and C4-5 posterior foraminotomy. After surgery, she improved her maximum inspiratory pressure and respiratory function. LESSONS: Cervical canal and foraminal stenosis may cause hemidiaphragmatic paralysis due to radiculopathy-induced phrenic nerve palsy. Laminoplasty and posterior foraminotomy can restore respiratory dysfunction related to diaphragmatic paralysis by decompressing the ventral horn of the spinal cord and spinal nerve root.

Infratentorial developmental venous anomaly concurrent with a cavernoma and dural arteriovenous fistula.

OBJECTIVES: While developmental venous anomaly (DVA) may be associated with cavernous malformation, mixed vascular malformation associated with dural arteriovenous fistula (dAVF) has not been previously reported. We observed a case with rare association of infratentorial DVA, cavernous malformation, and dAVF that presented with cerebellar ataxia. We report our endovascular treatment for this complex cerebrovascular condition. CASE PRESENTATION: A 32-year-old woman with ataxia had an infratentorial DVA associated with a cavernoma and dAVF. The dAVF had two shunting points. The dAVF was fed by the posterior meningeal arteries and drained through the sigmoid sinus into the transverse sinus. The dAVF was also fed by the occipital artery and retrogradely drained through the left jugular bulb into the dilated collecting vein of the DVA. Endovascular embolization was performed for the dAVF and dilated collecting vein of the DVA. Postoperative complications did not occur after embolization with no recurrence for three years. CONCLUSIONS: This is the first reported case of infratentorial DVA associated with a cavernoma and dAVF. Endovascular treatment was effective in treating this symptomatic complex cerebrovascular disorder.

[Posterior Subthalamic Area, Pallidothalamic Tract, and Pedunculopontine Nucleus:Deep Brain Stimulation Targets for Parkinson's Disease and Essential Tremor].

This article reviews the stereotactic targets in the posterior subthalamic area(PSA), fields H1/H2 of Forel(pallidothalamic tract), and the pedunculopontine nucleus(PPN)to complement the preceding articles on stereotactic and functional neurosurgery for movement disorders in the present issue of No Shinkei Geka. Two regions within the subthalamus, the PSA and fields H1/H2 of Forel, are the revisited stereotactic targets to treat movement disorders. Currently, the PSA is often utilized to treat essential tremor and various types of tremor. Fields H1/H2 of Forel are investigated as a target for magnetic resonance-guided focused ultrasound to treat motor symptoms and motor complications in patients with Parkinson's disease. For the past twenty years, the PPN has been investigated to treat refractory gait freezing and fall in patients with Parkinson's disease. These revisited and novel targets may be utilized as substitutes and complements for the present standard stereotactic targets.

Thalamic Deep Brain Stimulation for Refractory Atypical Tremor after Encephalitis of Unknown Etiology: A Case Report.

Tremor associated with encephalitis is usually transient and rarely becomes chronic and refractory. Treatment for such tremor using deep brain stimulation (DBS) has not yet been reported. We report an uncommon case of chronic tremor after encephalitis of unknown etiology and its outcome treated with thalamic DBS. A 47-year-old man presented with a 6-month history of medically refractory tremor after non-infectious and probable autoimmune encephalitis. The patient showed an atypical mixture of resting, postural, kinetic, and intention tremor. The tremor significantly disabled the patient's activities of daily life (ADL). The patient underwent bilateral thalamic DBS surgery. DBS leads were placed to cross the border between the ventralis oralis posterior (Vop) nucleus and ventralis intermedius (Vim) nucleus of the thalamus. Stimulation of both the Vop and Vim using the bipolar contacts controlled the mixed occurrence of tremor. The ADL and performance scores on The Essential Tremor Rating Assessment Scale (TETRAS) improved from 47 to 0 and from 44 to 9, respectively. The therapeutic effects have lasted for 24 months. Administration of combined Vop and Vim DBS may control uncommon tremor of atypical etiology and phenomenology.

Effects of acute angle, proximal bending, and distal bending in the deployment vessels on incomplete low-profile visualized intraluminal support (LVIS) expansion: an in vitro study.

BACKGROUND: A low-profile visualized intraluminal support (LVIS) device may incompletely expand during stent deployment in tortuous vessels. However, the cause of incomplete expansion remains uninvestigated. We aimed to examine in vitro the factors causing incomplete expansion in LVIS deployment by using various vessel models. METHODS: A linear model group was created by connecting linear silicone tubes (inner diameter 4 mm) at both sides of the LVIS deployment vessel (inner diameter 4 mm) with different curvature angles of 10-140° at 10° intervals. For comparison, proximal and distal bending model groups were created, both with 90° bending on the proximal/distal larger curvature side of the deployment vessel. A single operator macroscopically deployed an LVIS (4.5×32 mm) four times in each model and 56 times in each group. RESULTS: In each model group the LVIS deployment vessel with a narrow curvature angle incompletely expanded. Incomplete expansion occurred significantly more frequently in the distal bending model group (34%, 19/56) compared with that in the linear model group (14.3%, 8/56; p<0.001), as well as in the proximal bending model group (59%, 33/56) compared with that in the distal bending model group (p<0.05). Compared with the linear model group, the proximal bending model group had a significantly reduced angle between the LVIS and the direction of the LVIS pushing force, but no significant change was found in the distal bending model group compared with that in the linear model group. CONCLUSIONS: Factors such as acute angle, distal bending, and proximal bending of the deployment vessel can cause incomplete LVIS expansion.

Multiple Spinal Chronic Subdural Hematomas Associated with Thoracic Hematomyelia: A Case Report and Literature Review.

BACKGROUND: Chronic subdural hematoma (CSDH) is uncommon in the spine. Most spinal CSDHs occur as solitary lesions in the lumbosacral region. We report a rare case of multiple spinal CSDHs associated with hematomyelia. The diagnostic and therapeutic management of these complex spinal CSDHs is reviewed as well as the pertinent literature. CASE DESCRIPTION: A 79-year-old woman on warfarin therapy presented with lower back pain and progressive lower extremity weakness that had developed in the previous 2 weeks. She subsequently developed paraplegia and urinary incontinence. Thoracolumbar magnetic resonance imaging showed a CSDH from T12-L3 compressing the cauda equina. Single-shot whole-spine magnetic resonance imaging showed another CSDH and hematomyelia at T2-3. She underwent L2-3 hemilaminectomy, which revealed a liquefied subdural hematoma. Delayed T2 laminectomy exposed an organized subdural hematoma and xanthochromic hematomyelia. After each surgery, the patient showed significant motor recovery. Finally, the patient could walk, and the urinary catheter was removed. CONCLUSIONS: Spinal CSDH may occur in multiple regions and may be associated with hematomyelia. Whole-spine magnetic resonance imaging is useful to examine the entire spine for CSDH accurately and thoroughly. Comprehensive surgical exploration of all symptomatic hematomas may restore neurologic functions even with delayed surgery.

Two cases of primary ocular adnexal lymphomas diagnosed after pre-biopsy corticosteroid treatment using polymerase chain reaction-based gene rearrangement analysis.

PURPOSE: To report the limited usefulness of polymerase chain reaction (PCR)-based immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangement analysis in diagnosing primary ocular adnexal lymphomas (OAL) treated with corticosteroids before biopsy. OBSERVATIONS: This was a case series of two patients: a 47-year-old woman and a 43-year-old man, who both presented with impaired visual acuity and ophthalmoplegia of the involved eyes. Both patients had previously received non-diagnostic biopsy and had been subsequently treated with corticosteroids. The visual acuity and ophthalmoplegia progressively worsened after a variable duration of remission. Ocular magnetic resonance imaging revealed gadolinium-enhancing intra- and extraconal lesions. Systemic evaluations did not reveal any other lesions outside of the orbit. Differential diagnoses were lymphoproliferative disorders, including undiagnosed primary OALs, and idiopathic ocular inflammation. Both patients were exposed to repeated biopsies. The biopsied tissue demonstrated marked lymphocytolysis due to corticosteroid usage; therefore, histology and immunophenotype were non-diagnostic. EuroClonality/BIOMED-2 PCR-based gene rearrangement analyses detected genetic clonalities of Ig and TCR and suggested diagnoses of primary OALs of B-cell and T-cell origins, respectively. An OAL of B-cell origin was treated with radiotherapy; an OAL of a rare T-cell origin was treated with high-dose methotrexate-based chemotherapy and adjuvant radiotherapy. Both patients remained progression free for more than 36 months. CONCLUSIONS AND IMPORTANCE: PCR-based gene rearrangement analysis can be of limited usefulness in suggesting a diagnosis of primary OAL in patients receiving pre-biopsy corticosteroid treatment. Identification of genetic clonality is of clinical importance to provide treatment options for undiagnosed OALs.

Prosthesis Used in Microvascular Decompressions: A Multicenter Survey in Japan Focusing on Adverse Events.

OBJECTIVE: To investigate the characteristics of materials used as prostheses for microvascular decompression surgery (MVDs) in Japan and their possible adverse events (AEs) to determine preferable materials for MVDs. METHODS: A questionnaire was sent to all members of the Japanese Society for MVDs, and answers were obtained from 59 institutions. RESULTS: Among a total of 2789 MVDs, 1088 operations for trigeminal neuralgia, 1670 for hemifacial spasm, and 31 others, including 117 reoperations, were performed between April 2011 and March 2014. Nonabsorbable material was used in 96.5% of MVDs, including polytetrafluoroethylene (PTFE) (80.5%), polyurethane (11.9%), expanded PTFE (2.1%), and silk thread (1.47%). The use of absorbable materials, including fibrin glue (87.5%), cellulose (13.5%), gelatin (4,77%), and collagen (1.76%), was reported. The major combinations were PTFE with fibrin glue (58.7%) followed by PTFE alone (7.60%). Eighty-eight AEs in 85 (3.2%) cases were reported among 2672 first operations. AEs included 51 central nervous system dysfunctions, 15 wound infections/dehiscence, and 10 others, which were presumed to be related to the intraoperative procedure. Among relatively high-, moderate-, and low-volume centers, there were no significant differences in the frequency of AEs (P = 0.077). Tissue-prosthesis adhesion and/or granuloma formation were reported in 13 cases of 117 reoperations. The incidence of adhesion-related recurrence was 11.1% of all reoperations. CONCLUSIONS: The number of AEs was quite low in this survey, and intradural use of any prosthesis reported in this paper might be justified; however, further development of easily handled and less-adhesive prosthesis materials is awaited.

[Risk Factors for Early Progression of Carotid Stenosis after Cervical Radiation Therapy].

OBJECTIVE: Carotid stenosis may occur as a late complication following cervical radiation therapy(RT);however, it may also progress in the early post-RT period. This study aimed to characterize the clinical features associated with the early progression of post-RT carotid stenosis. METHODS: We retrospectively reviewed clinical records of 30 patients who had undergone unilateral or bilateral cervical RT between January 2010 and November 2014. We analyzed the pre- and post-RT stenosis of their carotid arteries using contrast-enhanced computed tomography images. The arteries were classified as progressive or non-progressive according to the presence or absence of stenosis progression within five years after RT. Using univariate and multivariate analyses, we evaluated the following potential clinical risk factors:age;gender;history of hypertension, hyperlipidemia, diabetes mellitus, coronary artery disease, or smoking habit;antiplatelet or statin use;radiation dose;and prior presence of carotid stenosis before RT. RESULTS: In total, we reviewed 57 irradiated carotid arteries and identified 9 with early post-RT progression. Carotid stenosis before RT was observed in 88.9% of arteries in the progressive group but only 2% of arteries in the non-progressive group and it predicted progression(univariate and multiple logistic regression analyses, p<0.0001). No other clinical characteristics had a significant association with the progression of carotid stenosis. CONCLUSION: Prior presence of carotid stenosis may be a risk factor for its early progression after RT. Pre-RT screening of cervical arteries may be useful, and strict management of carotid stenosis is critical in patients with cervical radiation therapy.

Nervus Intermedius Section to Mobilize the Anterior Inferior Cerebellar Artery in Microvascular Decompression Surgery for Hemifacial Spasm: A Technical Case Report.

BACKGROUND: The course of the anterior inferior cerebellar artery (AICA) in the cerebellopontine angle may affect the technical options in microvascular decompression surgery for hemifacial spasm. A complex relationship between the AICA and the nervus intermedius has rarely been discussed in patients with hemifacial spasms. CASE DESCRIPTION: A 74-year-old woman presented with left facial spasms for 8 years. Intraoperative endoscopic observation confirmed that the left nervus intermedius crossed over the left AICA and limited its mobilization from the root exit zone (REZ) of the left facial nerve. Nervus intermedius section enabled mobilization of the AICA to decompress the facial nerve REZ. Her hemifacial spasm was resolved completely after the surgery with no significant complication. CONCLUSIONS: The AICA may be found between the nervus intermedius and the facial nerve proper in patients with hemifacial spasm. Endoscope can visualize the relationship between the AICA and the nervus intermedius. Nervus intermedius section is a useful option in case that the nervus intermedius limits adequate mobilization of the AICA from the facial nerve REZ.

Extradural Anterior Clinoidectomy and Optic Canal Unroofing for Paraclinoid and Basilar Aneurysms: Usefulness of a No-Drill Instrumental Method.

The authors describe extradural anterior clinoidectomy without the use of a high-speed drill or ultrasonic device to clip paraclinoid and basilar aneurysms, which can eliminate potential complications related to traditional power drilling or ultrasonic device use. This method involves four steps: (1) partial osteotomy of the sphenoid wing at the superior orbital fissure (SOF); (2) peeling of the dura propria of the temporal lobe from the inner cavernous membrane of the SOF; (3) isolation and resection of the exposed meningo-orbital band to expose the superolateral aspect of the anterior clinoid process (ACP); and (4) piecemeal rongeuring of ACP and the roof of the optic canal. The entire procedure was performed using surgical instruments, including micro-rongeurs, a fine Kerrison punch, and micro-dissectors. Subsequently, intradural neck clipping was performed. Twenty consecutive patients with paraclinoid and basilar aneurysms successfully underwent clipping after this non-drill extradural clinoidectomy. Minor morbidity was noted in two patients (cerebrospinal fluid leakage in one and transient oculomotor palsy in the other). The non-drill method is a simple, easy, safe, and quick alternative to traditional power drilling in extradural clinoidectomy, and this method can avoid morbidity related to direct mechanical/thermal injury of important neurovascular structures.