Microsurgical treatment of recurrent coiled aneurysms.

The number of endovascularly-treated aneurysms has steadily increased over the past two decades. A small but significant number of recurrent or partially recanalized aneurysms have been identified. If repeat endovascular therapies are not feasible due to anatomical or technical considerations, surgical clipping may be considered. The technical challenges in the microsurgical treatment include coils interfering with the clip application; the possibility of an aneurysm that is less collapsible and less easy to manipulate; and intraluminal thrombus formation requiring thrombus and coil removal. The video presents the technical steps and nuances for clipping. The technical issues for coil removal are illustrated in two cases. The video can be found here: http://youtu.be/NvhSDVT4iuE.

Microsurgical Management of Internal Carotid Artery Bifurcation Aneurysm After Failure of Endovascular Coiling and Flow Diversion: 2-Dimensional Operative Video.

We describe the case of a 51-year-old woman who underwent craniotomy and surgical clipping of a large internal carotid bifurcation aneurysm that was refractory to treatment with 2 rounds of endovascular coiling and internal carotid artery (ICA) to middle cerebral artery pipeline placement. The patient initially presented in 2004 with a 3-week history of sudden-onset headache with associated nausea. Computed tomography and lumbar puncture on presentation in 2004 were negative for subarachnoid hemorrhage. Digital subtraction angiography, however, demonstrated a large left ICA bifurcation aneurysm. The decision was made to proceed with endovascular coiling of the aneurysm. Six-month and 1-year follow-up imaging showed incomplete resolution of the aneurysm, and retreatment coiling was completed in 2005. After recoiling in 2005, the patient was lost to follow-up. During this period, she underwent pipeline placement from the ICA to the middle cerebral artery across the A1 segment at a different institution. Two years after flow diversion, the patient was referred back to our institution with further worsening of the aneurysm. Our surgical team opted for craniotomy and surgical clipping given the limited management options that this extremely complex case now presented. The patient consented to the procedure. Postoperative imaging demonstrated marked improvement in aneurysm severity. Although the current neurosurgical trend favors endovascular treatment over craniotomy, this case shows the vital importance of craniotomy and aneurysm clipping in the treatment of select patients. We also provide high-quality operative video of aneurysm clipping.1-7.

A Transcriptomic Comparative Study of Cranial Vasculature.

In genetic studies of cerebrovascular diseases, the optimal vessels to use as controls remain unclear. Our goal is to compare the transcriptomic profiles among 3 different types of control vessels: superficial temporal artery (STA), middle cerebral arteries (MCA), and arteries from the circle of Willis obtained from autopsies (AU). We examined the transcriptomic profiles of STA, MCA, and AU using RNAseq. We also investigated the effects of using these control groups on the results of the comparisons between aneurysms and the control arteries. Our study showed that when comparing pathological cerebral arteries to control groups, all control groups presented similar responses in the activation of immunological processes, the regulation of intracellular signaling pathways, and extracellular matrix productions, despite their intrinsic biological differences. When compared to STA, AU exhibited upregulation of stress and apoptosis genes, whereas MCA showed upregulation of genes associated with tRNA/rRNA processing. Moreover, our results suggest that the matched case-control study design, which involves control STA samples collected from the same subjects of matched aneurysm samples in our study, can improve the identification of non-inherited disease-associated genes. Given the challenges associated with obtaining fresh intracranial arteries from healthy individuals, our study suggests that using MCA, AU, or paired STA samples as controls are feasible strategies for future large-scale studies investigating cerebral vasculopathies. However, the intrinsic differences of each type of control should be taken into consideration when interpreting the results. With the limitations of each control type, it may be most optimal to use multiple tissues as controls.

Somatic Variants in SVIL in Cerebral Aneurysms.

Background and Objectives: While somatic mutations have been well-studied in cancer, their roles in other complex traits are much less understood. Our goal is to identify somatic variants that may contribute to the formation of saccular cerebral aneurysms. Methods: We performed whole-exome sequencing on aneurysm tissues and paired peripheral blood. RNA sequencing and the CRISPR/Cas9 system were then used to perform functional validation of our results. Results: Somatic variants involved in supervillin (SVIL) or its regulation were found in 17% of aneurysm tissues. In the presence of a mutation in the SVIL gene, the expression level of SVIL was downregulated in the aneurysm tissue compared with normal control vessels. Downstream signaling pathways that were induced by knockdown of SVIL via the CRISPR/Cas9 system in vascular smooth muscle cells (vSMCs) were determined by evaluating changes in gene expression and protein kinase phosphorylation. We found that SVIL regulated the phenotypic modulation of vSMCs to the synthetic phenotype via Krüppel-like factor 4 and platelet-derived growth factor and affected cell migration of vSMCs via the RhoA/ROCK pathway. Discussion: We propose that somatic variants form a novel mechanism for the development of cerebral aneurysms. Specifically, somatic variants in SVIL result in the phenotypic modulation of vSMCs, which increases the susceptibility to aneurysm formation. This finding suggests a new avenue for the therapeutic intervention and prevention of cerebral aneurysms.

Incidence and predictors of intracranial hemorrhage after minor head trauma in patients taking anticoagulant and antiplatelet medication.

BACKGROUND: The yield of head computed tomography (CT) for patients who suffered head trauma with a presenting Glasgow Coma Scale (GCS) score of 15 has been reported to be low, even in patients who are anticoagulated or on antiplatelet therapy. We undertook this study to (1) determine the frequency of intracranial hemorrhage in anticoagulated patients and patients on antiplatelet therapy and its impact on clinical management, (2) identify predictors of positive imaging findings, and (3) assess potential differences between anticoagulation and antiplatelet therapy. METHODS: We conducted a retrospective review of the trauma registry at our institution, a Level II trauma center. All trauma registry patients with a minor head injury registered between the years 2004 and 2006 who were taking warfarin or clopidogrel, had a presenting GCS score of 15, and underwent head CT were included in this study. Intracranial hemorrhage on head CT was considered a positive result. RESULTS: One hundred forty-one patients (male, n=67; female, n=74), mean age 79 years (range, 36-101 years), were included in this study. Forty-one patients (29%) were diagnosed with intracranial hemorrhage. Thirty-nine (95%) of these 41 patients underwent reversal and/or discontinuation of clopidogrel and/or warfarin. Five patients required surgical evacuation of an intracranial hemorrhage. Four patients died. Loss of consciousness (Wald=7.468, ß=1.179, p=0.008) predicted a positive CT result. Type of medication (warfarin, aspirin, or clopidogrel) did not reach statistical significance as a predictor of positive result. CONCLUSION: Despite a presenting GCS score of 15, patients with minor head injury from the trauma registry at our institution taking anticoagulation or antiplatelet therapy have a high incidence of intracranial hemorrhage especially after reported loss of consciousness.

Postoperative resolution of abnormal blood vessels related to a nerve root hemangioblastoma.

To our knowledge, there are currently no published reports that describe the postoperative evolution of abnormal blood vessels associated with spinal nerve root hemangioblastomas. We present a patient with a hemangioblastoma that was completely resected. Follow-up imaging revealed complete resolution of the abnormal blood vessels. We hypothesize that complete resection of spinal nerve root hemangioblastomas eliminates the venous hypertension and allows for regression of the dilated vascular network. Persistent dilated vessels should be followed closely for residual tumors.

Orbital reconstruction for tumor-associated proptosis: quantitative analysis of postoperative orbital volume and final eye position.

OBJECTIVE: Surgical resection of sphenoid wing tumors and intraorbital pathology carries the dual goal of appropriately treating the target pathology as well as correcting proptosis. Residual proptosis following surgery can lead to cosmetic and functional disability. The authors sought to quantitatively assess the effect of orbital volume before and after reconstruction to determine the optimal strategy to achieve proptosis correction. METHODS: All surgeries involving orbital wall reconstruction for orbital or intracranial pathology that preoperatively resulted in proptosis between 2007 and 2017 were reviewed. Proptosis was measured by the exophthalmos index (EI): the ratio of the distance of the anterior limit of each globe to a line drawn between the anterior limit of the frontal processes of the zygomas, comparing the pathological eye to the normal eye. Postoperative radiographic measurements were taken at least 60 days after surgery to allow surgical swelling to abate. The orbit contralateral to the pathology was used as an internal control for normal anatomical orbital volume. Cases with preoperative EI < 1.10, orbital exenteration, or enucleation were excluded. RESULTS: Twenty-three patients (16 females and 7 males, with a mean age of 43.6 ± 22.8 years) were treated surgically for tumor-associated proptosis. Nineteen patients harbored meningiomas (11 en-plaque; 8 sphenoid wing), and one patient each harbored an orbital schwannoma, glomangioma, arteriovenous malformation, or cavernous hemangioma. Preoperative EI averaged 1.28 ± 0.10 (range 1.12-1.53). Median time to postoperative imaging was 19 months. Postoperatively, the EI decreased to a mean of 1.07 ± 0.09. Greater increases in size of the reconstructed orbit were positively correlated with greater quantitative reductions in proptosis (p < 0.01). Larger volume of soft tissue pathology was also associated with achieving greater proptosis correction (p < 0.01). Residual exophthalmos (defined as EI > 1.10) was present in 8 patients, while reconstruction in 2 patients resulted in clinically asymptomatic enophthalmos (defined as EI < 0.95). Tumor invasion into the superior orbital fissure sinus was associated with residual proptosis (p = 0.04). CONCLUSIONS: Proptosis associated with intracranial and orbital pathology represents a surgical challenge. The EI is a reliable and quantitative assessment of proptosis. For orbital reconstruction in cases of superior orbital fissure involvement, surgeons should consider rebuilding the orbit at slightly larger than anatomical volume.

Superficial temporal artery dissection: a technical note.

BACKGROUND: Dissection of the superficial temporal artery (STA) is often required in preparation for a bypass procedure. Traditionally, dissection of the STA involves a direct cutdown on the artery after marking the course of the artery on the skin with the help of a Doppler ultrasound probe. OBJECTIVE: We describe a method that takes advantage of the position of the STA superficial to the temporal fascia. METHODS: The technique was used in a total of 38 procedures in 32 patients to create synangiosis or extracranial-intracranial STA bypasses. The STA was dissected using a blunt malleable brain retractor that was inserted into the subgaleal plane directly over the STA, allowing creation of a linear incision and concurrent protection of the STA in its bed. Either computed tomography- or catheter-based angiography was used to evaluate the patency postoperatively. RESULTS: All STA vessels were dissected without complications or injury to the graft vessel. The sole complication was a superficial wound breakdown in a synangiosis case. Postoperative angiography demonstrated patency in all but 1 of the 24 bypass cases (95.8%). CONCLUSION: We describe a method that takes advantage of the position of the STA superficial to the temporal fascia to allow rapid, safe, and efficacious dissection. The incision is linear and easier to manage and close. In our series, there were no technical complications related to the dissection of the STA.

Obliteration of a metameric spinal arteriovenous malformation (Cobb syndrome) using combined endovascular embolization and surgical excision.

Cobb syndrome represents the concurrent findings of a metameric spinal vascular malformation and a cutaneous vascular malformation within several dermatomes of each other. This rare entity engenders many difficult decisions with respect to appropriate therapeutic management. Historically, surgical excision carried a high morbidity, and conservative management without intervention was preferred. More recently, several cases of endovascular embolization have been reported with good success. The authors describe the case of a 17-year-old boy who presented with a right gluteal angioma and was found to have a spinal arteriovenous malformation. Multiple embolizations failed to prevent neurological deterioration, and the patient eventually became wheelchair dependent. Surgical excision of the malformation led to partial recovery of neurological function, and at the latest follow-up, 52 months postoperatively, the patient was able to ambulate independently. This case demonstrates the successful treatment of a patient with Cobb syndrome with surgical excision after multiple refractory embolizations. A multidisciplinary approach, which balances the patient's current neurological function against the risks and potential gains from any interventional and surgical procedure, is recommended.

Lumbar microdiscectomy and microendoscopic discectomy.

Lumbar microdiscectomy, which relies on the operating microscope for visualization, was first described in the late 1970s. This operation is considered the gold standard procedure for patients who require surgery for symptomatic lumbar disc herniation causing radiculopathy that has not improved with conservative measures. A new approach to the management of symptomatic lumbar disc herniation, microendoscopic discectomy, was introduced in 1997. This operation utilizes a tubular retractor system and a microendoscope for visualization rather than the operating microscope. As it is a new procedure, long-term outcomes have not yet been established for this operation. However, recent literature suggests that microendoscopic discectomy may be as effective as the traditional lumbar microdiscectomy in relieving radiculopathy. This article describes the operative techniques and outcomes reported in the literature for both lumbar microdiscectomy and microendoscopic discectomy.