Single-lane clipping technique for a ruptured aneurysm of A1 fenestration of the anterior cerebral artery: a case report and literature review.

Fenestration of the A1 segment of the anterior cerebral artery is a rare vascular anomaly with a high risk of saccular aneurysm at the proximal end of the A1 fenestration. These aneurysms have a high risk of rupture. However, conventional surgical clipping can be technically challenging due to the anatomical characteristics. We report a case of A1 fenestration with a ruptured aneurysm wherein we successfully achieved complete obliteration of the aneurysm with a new "single-lane" clipping technique. A 64-year-old woman presented with a ruptured saccular A1 aneurysm at the proximal end of an A1 fenestration, resulting in subarachnoid hemorrhage. Microsurgical clipping was attempted; however, adequate exposure of the aneurysm could not be achieved. The recurrent artery of Heubner originated near the distal end of the lateral limb of the A1 fenestration. The lateral limb of the A1 fenestration had no perforating arteries, according to surgical examination. Thus, the aneurysm neck and lateral limb were concurrently obliterated using a nonfenestrated clip, preserving the medial limb of the A1 fenestration. The antegrade flow of the recurrent artery of Heubner was detected using the retrograde flow of the distal part of the lateral limb of the A1 fenestration during intraoperative indocyanine green video angiography. The postoperative course was uneventful without any evidence of ischemic stroke. For A1 aneurysms arising from the proximal end of the A1 fenestration, this technique may be a useful treatment option. Before using this technique, careful surgical exploration should be performed to assess the A1 perforating arteries.

Correlations Among Consistency, Computed Tomography Values, and Histopathological Subtypes of Spinal Meningioma.

The consistency of spinal meningiomas is important to consider when performing tumor removal surgery. This study evaluated the correlations between spinal meningioma consistency and both preoperative computed tomography (CT) values and histopathological subtypes. Fifteen consecutive patients who underwent surgical resection of spinal meningioma at our institution were identified, and preoperative CT values and the signal intensity of T2-weighted magnetic resonance images of the tumor were determined retrospectively. The consistency of the spinal meningioma was defined based on the ultrasonic surgical aspirator output during tumor debulking. Patients were assigned to 2 groups: a soft group (n=4) and a hard group (n=11). The T2 signal intensity was significantly higher in the soft group than in the hard group (p=0.001). While the CT values were considerably higher in the hard group, the difference was not significant (p=0.19). Regarding the histopathological subtypes, psammomatous meningioma exhibited significantly higher CT values than meningothelial meningioma (p=0.019); however, there was a higher frequency of hard tumors in meningothelial meningioma cases than in psammomatous meningioma cases. Although neither robust correlations between tumor consistency and CT values nor a relationship between tumor consistency and histopathological subtype has been established, these results might help with the perioperative manegement of spinal tumors.

Calcified ectopic TSH-secreting pituitary adenoma mimicking craniopharyngioma: a rare case report and literature review.

Among pituitary adenomas, which are relatively common brain tumors, elements of ectopic, thyroid-stimulating hormone (TSH) secretion, and intratumoral calcification are unusual. Here, we present an extremely rare case of a calcified ectopic TSH-secreting pituitary adenoma arising from the pars tuberalis mimicking craniopharyngioma based on neuroimaging findings. To our knowledge, this is the first case report of calcified ectopic TSH-secreting pituitary adenoma without symptoms of excessive thyroid hormone secretion.

Risks of Endoscopic Temporal Ventriculocisternostomy for Isolated Lateral Ventricle: Anatomic Surgical Nuances.

BACKGROUND: Entrapment of the temporal horn, known as isolated lateral ventricle (ILV), is a rare type of noncommunicating focal hydrocephalus, and standard treatment has not been established. We report 2 cases of endoscopic surgery for ILV and highlight the anatomic surgical nuances to avoid associated surgical risks. CASE DESCRIPTION: The first patient presented with recurrent ILV following initial shunt placement for ILV, owing to shunt malfunction. In the second patient, ILV recurred secondary to choroid plexus inflammation caused by cryptococcal infection. Endoscopic temporal ventriculocisternostomy was effective in both cases. However, in the second case, the choroidal fissure was fenestrated, which led to cerebral infarction in the territory of the choroidal artery zone, attributed to damage of the branches of the choroidal segment of the anterior choroidal artery. CONCLUSIONS: Although endoscopic temporal ventriculocisternostomy is considered a safe and less invasive procedure for treatment of symptomatic ILV, the technique is still associated with risks. To avoid complications, it is necessary to be familiar with the anatomy of the choroidal arteries and the pertinent endoscopic intraventricular orientation. Additionally, sufficient experience is required before it can be recommended as the treatment of choice.

A Case of Laterally Extended High-Positioned Chordoma Treated Using the High Cervical Retropharyngeal Approach.

BACKGROUND: Several surgical approaches for the treatment of pathologies of the craniovertebral junction (CVJ) and high cervical regions have been reported. For the best postoperative results, selection of a surgical route to treat such pathologies should be based on a complete understanding of the approach. CASE DESCRIPTION: A 64-year-old woman presented with a 5-year history of motor and sensory disturbances in her right upper extremity. Cervical magnetic resonance imaging (MRI) showed a slightly enhanced mass at the C2-C4 level. Sagittal T2-weighted MRI revealed a hyperintense dumbbell-shaped mass involving a damaged C3 vertebral body. We performed a 2-stage operation to achieve gross total removal of the tumor. In the first operation, a posterior approach was used to remove the intracanalicular tumor, achieve spinal cord decompression, and establish a histological diagnosis of the tumor (subsequently diagnosed as a chordoma). In the second operation, gross total removal of the chordoma was achieved via the anterior high cervical retropharyngeal approach. We used iliac bone and titanium plates for the bony fusion. CONCLUSIONS: Our results indicate that the high cervical retropharyngeal approach is a reasonable option for pathologies located in the anterior or anterolateral portions of high cervical regions. This approach is an alternative to the transoral approach to the ventral CVJ and high cervical regions.

Expression of the JAK/STAT signaling pathway in the ligamentum flavum of patients with lumbar spinal canal stenosis.

BACKGROUND: Ligamentum flavum (LF) hypertrophy is an important cause of lumbar spinal canal stenosis (LSS), one of the most common spinal disorders in the elderly. Although many cytokines are reported to be associated with LF hypertrophy, the intracellular signaling system is rarely discussed. The purpose of this study was to identify the JAK/STAT signaling pathway and to examine the role of the JAK/STAT systems in the hypertrophied LF. METHODS: The LF of 10 LSS patients was analyzed and the expression of JAK1, STAT3, phosphorylated (p)-STAT3, and actin was examined by Western blot analysis. The expression of p-STAT3 was also examined by immunostaining and its positive cell ratio was compared between LSS and non-LSS samples. We measured the thickness of the LF on magnetic resonance images and studied the relationship between its thickness and the expression of p-STAT3. RESULTS: JAK1, STAT3, and p-STAT3 were detected in almost all samples by Western blot analysis. Immunoreactivity against p-STAT3 was observed mainly in endothelial- and fibroblast-like cells. The expression of p-STAT3 was significantly higher in LSS than non-LSS samples; it was significantly stronger on the dorsal than the dural side of the LF and positively correlated with the thickness of the LF on the dorsal side. CONCLUSIONS: The JAK/STAT signaling pathway is positively correlated with the thickness of the LF. Our findings suggest that JAK1 and STAT3 molecules are involved in and regulate LF hypertrophy.

Relationship Between Muscle Dissection Method and Postoperative Muscle Atrophy in the Lateral Suboccipital Approach to Vestibular Schwannoma Surgery.

BACKGROUND: Various techniques are available for occipital skull exposure with muscle dissection, as well as different types of skin incisions in the lateral suboccipital approach to vestibular schwannoma (VS) surgery. The skin incisions are generally classified as S-shaped, J-shaped, or C-shaped. In each method, the technique used for muscle dissection differs in terms of cut, single layer, and multiple layers. This study was performed to identify the relationships among muscle dissection method, skin incision type, and muscle atrophy in the lateral suboccipital approach to surgery for VS. METHODS: Between 2002 and 2011, we performed surgical resection in 53 patients with VS at Shinshu University Hospital. Of these 53 patients, 35 with radiographic annual follow-up for >3 years after surgery were evaluated retrospectively. These patients included 14 who underwent an S-shaped incision, 6 with a J-shaped incision, and 15 with a C-shaped incision. Bilateral areas of the skin and occipital muscles were measured, and rates of atrophy were calculated and compared among the 3 methods. RESULTS: Postoperative muscle atrophy was significantly advanced in the second postoperative year, but did not tend to develop further after the third year. The postoperative muscle atrophy ratio was significantly lower in the C-shaped incision group (mean ± SD, 4.0% ± 6.9%) compared with the S-shaped (17.1% ± 9.8%) and J-shaped (17.6% ± 10.0%) incision groups within 2 years after surgery (P < 0.05). CONCLUSIONS: The C-shaped skin incision with multilayer muscle dissection was associated with significantly reduced postoperative muscle atrophy compared with the other methods.

Surgery for ventral intradural thoracic spinal tumors with a posterolateral transpedicular approach.

BACKGROUND: Surgery for ventrally seated thoracic tumors requires an anatomically specific approach that is distinct from cervical or lumbar spinal cord surgery as the narrower spinal canal of the thoracic spinal cord makes it sensitive to surgical procedures. However, reports describing this operative technique are few. To obtain a wide operative field and minimize thoracic spinal cord retraction, we employed a posterolateral transpedicular approach in ventral-located tumors and investigated the efficacy and limitations of this technique. METHOD: Eighteen patients with lesions (meningioma or neurinoma) located in the ventral intradural thoracic region were surgically treated between 2009 and 2014. The relationship among the clinical outcome, tumor location, and postoperative spinal alignment was analyzed. RESULTS: Postoperative neurological function improved in all patients, namely those with meningioma (p = 0.012) and schwannoma (p = 0.018). One patient who underwent removal of two facet joints suffered a postoperative compression fracture. Removal of two facet joints and pedicles resulted in a worsening of spinal alignment (p = 0.03), while this was not the case for the removal of one facet joint and pedicle (p = 0.72). CONCLUSIONS: This case series clarified the benefits of the posterolateral transpedicular approach for resection of ventral intradural extramedullary tumors. Removal of one pedicle and facet joint seems to be more beneficial.

Novel dural incision and closure procedure for preventing postoperative cerebrospinal fluid leakage during the surgical removal of dumbbell-shaped spinal tumors: technical note.

The authors report on a new method for removing dumbbell-shaped spinal tumors that avoids the risk of postoperative cerebrospinal fluid (CSF) leakage. Adequate visualization of the intra- and extradural components of the tumor is achieved with the use of separate dural incisions. First, the dura mater is opened along the dural theca to provide adequate visualization of the intradural portion of the mass; then, a second incision is made along the nerve root to remove the extradural component. Meticulous suturing is essential in intradural lesion cases; however, the dura mater is usually thin and fragile in such cases. During suturing with a needle and thread, the dura mater can become lacerated proximal to the needle holes and result in CSF leakage. In the authors' technique, instead of using a needle and thread, nonpenetrating vascular clips were used to close the dural incisions. When operating on dumbbell-shaped spinal tumors, the authors found that the "separate-dural-incision method" was preferable to the conventional T-shaped dural incision method because no dural defects occurred after the intradural procedure and meticulous dural closure with vascular clips was achieved. The authors conclude that the novel separate-dural-incision method for removing dumbbell-shaped tumors and the use of nonpenetrating vascular clips permits reliable dural closure, prevents postoperative CSF leakage, and promises good postoperative clinical results.

Long Segment Spinal Dural Cyst: A Case Report.

BACKGROUND: Spinal meningeal cysts are a rare benign disease that can cause myelopathy. In most cases, spinal meningeal cysts consist of an arachnoid membrane. To the best of our knowledge, few articles have report on intradural spinal meningeal cyst consisting of dura mater. CASE DESCRIPTION: A 58-year-old man presented to our institute with aggravation of clumsy hands and dysesthesia of the feet. Magnetic resonance imaging of the entire spine revealed a cystic lesion compressing the spinal cord posteriorly. Cyst fenestration and placement of the cyst-subarachnoid shunt was performed via an anterior approach. Postoperatively, the histopathologic results revealed that the cyst wall consisted of a dura mater-like membrane. The patient's symptoms resolved without the appearance of any new neurologic deficits. CONCLUSIONS: The etiology of spinal meningeal cysts remains unclear. Spinal meningeal cysts consisting of dura mater (spinal dural cysts) are extremely rare. Treatment with only decompression with laminectomy causes enlargement of the dural cyst later. Cyst fenestration and placement of a cyst-subarachnoid shunt for the spinal dural cyst resulted in the resolution of myelopathy and cyst shrinkage.

Iatrogenic dural arteriovenous fistula after radical neck dissection for metastatic malignant disease: A case report.

BACKGROUND: A case of dural arteriovenous fistula (dAVF) developed after radical neck dissection for lymph node metastasis 2 years after oral surgery for tongue cancer. METHODS: The patient was asymptomatic during follow-up visits with no evidence of metastasis on follow-up CT scan of the neck. However, diagnostic angiography showed left internal carotid artery (ICA) stenosis and dAVF involving the posterior meningeal artery and transverse sinus at the left posterior fossa with cortical venous reflux (Cognard type III). They were treated with carotid stenting and surgery, respectively. RESULTS: The postoperative course was uneventful. Follow-up angiography revealed obliteration of the dAVF. CONCLUSION: This was a rare case of iatrogenic dAVF after surgical ligation of venous outflow during radical neck dissection. The surgical plan is presented along with a literature review regarding the development of iatrogenic dAVFs induced by direct surgical trauma.

Posterior Laminoplastic Laminotomy Combined with a Paraspinal Transmuscular Approach for Removing a Lumbar Dumbbell-shaped Schwannoma: A Technical Note.

The surgical strategies and methods used to treat dumbbell-shaped tumors located in the lumbar-foraminal region are controversial. Although a total facetectomy and combined intra- and extraspinal canal approach provide a wide operative field, facet fusion is required, which can be rather invasive. Here, we report a successful removal of a lumbar dumbbell-shaped schwannoma using a combined laminoplastic laminotomy with Wiltse's paraspinal surgical approach. This was performed under an operating microscope without a complete facetectomy, fusion, and posterior fixation. Briefly, we treated two patients with lumbar foraminal tumors, both dumbbell-shaped schwannomas located in the intra- and extradural portion. After a laminoplastic laminotomy, the intradural tumor was removed. The tumor located at the extracanalicular site was removed after drilling the pars interarticularis of the lamina, which was performed to enlarge the intervertebral foramen via Wiltse's paraspinal surgical approach. During surgery, facetectomy with posterior fixation was not needed to remove the intraforaminal component. There was no lumbar instability or complication after surgery. Our results suggest that a combined posterior laminoplastic laminotomy and Wiltse's paraspinal surgical approach is useful and less invasive for treating patients with lumbar foraminal tumors.

Bony surface registration of navigation system in the lateral or prone position: technical note.

BACKGROUND: Navigation systems have become essential tools in neurosurgery. Precise registration is indispensable for the accuracy of navigation. The rapid and precise registration by surface matching on the facial skin is possible using the landmarks of the face in the supine position. On the other hand, incomplete registration often occurs in the lateral or prone position due to the direction of the face and displacement of the skin by headpins and obscuring of the skin by the bispectral index monitor and many electrodes on the forehead as well as the eye patch. Surface matching on the occipital scalp is not suitable for registration because the shape of the occipital scalp is flat and it is compressed in the supine position when obtaining preoperative neuroimaging. To overcome this problem, the authors have developed a new method of registration designated as "bony surface registration" in which surface matching is achieved using the bony surface of the skull after exposure. METHODS: Between June and December 2014, this technique was used in 23 patients and its effectiveness was examined. RESULTS: Registration time was markedly shortened and useful navigation was achieved due to accurate registration in all patients. CONCLUSIONS: This is the first report of a registration methodology for a navigation system in the lateral or prone position. This bony surface registration method is useful for navigation system image-guided surgery in the lateral or prone position.

Utility of nonpenetrating titanium clips for dural closure during spinal surgery to prevent postoperative cerebrospinal fluid leakage.

OBJECT: The nonpenetrating titanium clip has been successfully used in peripheral arterial bypass surgery. The purpose of this study was to evaluate the leakage pressures and patterns of nonpenetrating titanium clips using a simple model that mimicked spinal surgery. In addition, the authors describe their surgical experience with these clips and the follow-up results in 31 consecutive patients. METHODS: The authors compared nonpenetrating titanium clips and expanded polytetrafluoroethylene (ePTFE) sutures in relation to the water pressure that could be tolerated by sutured ePTFE sheets, and the leakage pressure patterns were determined. The changes in leakage pressures at 5 minutes, 30 minutes, and 12 hours were examined when the clips and sutures were used in combination with the mesh-and-glue technique in an in vitro study. Thirty-one patients underwent spinal intradural procedures using nonpenetrating titanium clips to suture the dura maters using the meshand-glue technique, involving fibrin glue and polyglycolic acid-fibrin sheets. RESULTS: A significant difference was apparent between the ePTFE suture group and the nonpenetrating titanium clip group, with the latter showing a leakage pressure that could be sustained and was 1508% higher than that of the former (p = 0.001). In relation to leakage patterns, the nonpenetrating titanium clips did not make any suture holes in the ePTFE sheet and fluid leakage occurred between the clips, whereas fluid leakage was associated with the pressure elevation that occurred at the suture holes made by the ePTFE sutures. Of the 31 patients who underwent spinal intradural procedures using nonpenetrating titanium clips, 1 (3.2%) experienced cerebrospinal fluid (CSF) leakage postoperatively. No other complications-for example, allergic reactions, adhesions, or infections--were encountered. CONCLUSIONS: The interrupted placement of nonpenetrating titanium clips enables dural closure without creating any holes. These clips facilitate improvements in the initial leakage pressure and reduce postoperative CSF leakage following spinal surgery. The authors conclude that it is very beneficial to suture the spinal dura mater using nonpenetrating titanium clips given the anatomical characteristics of the spinal dura mater and the fact that the clips do not create suture holes.

Surgical Strategies for Cervical Spinal Neurinomas.

Cervical spinal neurinomas are benign tumors that arise from nerve roots. Based on their location, these tumors can also take the form of a dumbbell-shaped mass. Treatment strategies for these tumors have raised several controversial issues such as appropriate surgical indications and selection of surgical approaches for cervical dumbbell-shaped spinal neurinomas. In this report, we review previous literature and retrospectively analyze cervical spinal neurinoma cases that have been treated at our hospital. Surgical indications and approaches based on tumor location and severity are discussed in detail. Thus, with advances in neuroimaging and neurophysiological monitoring, we conclude that appropriate surgical approaches and intraoperative surgical manipulations should be chosen on a case-by-case basis.

Radiographic measurements of C-2 in patients with atlas assimilation.

OBJECT: The object of this study was to evaluate the radiographic characteristics of C-2 using multiplanar CT measurements for anchor screw placement in patients with C-1 assimilation (C1A). Insertion of a C-2 pedicle screw in the setting of C1A is relatively difficult and technically demanding, and there has been no report about the optimal sizes of the pedicles and laminae of C-2 for screw placement in C1A. METHODS: An institutional database was searched for all patients who had undergone cervical CT scanning and cervical spine surgery between April 2006 and December 2012. Two neurosurgeons reviewed the CT scans from 462 patients who met these criteria, looking for C1A and other anomalies of the craniocervical junction such as high-riding vertebral artery (VA), basilar invagination, and VA anomaly. The routine axial images were reloaded on a workstation, and reconstruction CT images were used to measure parameters: the minimum width of bilateral pedicles and laminae and the length of bilateral laminae of the atlas. RESULTS: Seven patients with C1A were identified, and 14 sex-matched patients without C1A were randomly selected from the same database as a control group. The mean minimum pedicle width was 5.21 mm in patients with C1A and 7.17 mm in those without. The mean minimum laminae width was 5.29 mm in patients with C1A and 6.53 mm in controls. The mean minimum pedicle and laminae widths were statistically significantly smaller in the patients with C1A (p < 0.05). CONCLUSIONS: In patients with C1A, the C-2 bony structures are significantly smaller than normal, making C-2 pedicle screw or translaminar screw placement more difficult.

Cervical radiculopathy due to disc herniation with adjacent facet hypertrophy: case report.

We report a rare case of cervical radiculopathy associated with facet hypertrophy and disc herniation. The patient was a 38-year-old woman with sudden-onset left arm pain. As conservative therapy failed to alleviate her symptoms she was referred to us. On physical examination she manifested no neurological deficits except pain and dysesthesia in the left C7 territory. Computed tomography revealed hypertrophic ossified changes in the left T1 facet joint with encroachment on the spinal canal. Magnetic resonance imaging showed compression of the spinal cord at C6/7 by disc herniation at C6/7. Anterior cervical decompression and fusion by corpectomy (C7 corpectomy and C6/T1 fixation with a titanium cage) ameliorated her pain. Facet hypertrophy in a morphologically normal cervicothoracic spine is extremely rare and its etiology is unknown. We speculate the possibility that our patient harbored a congenital anomaly and that the morphologic changes were the consequence of an injury she sustained in a traffic accident.

Surgical strategy and results of treatment for dumbbell-shaped spinal neurinoma with a posterior approach.

OBJECTIVE: Total removal of neurinomas is generally an achievable goal that yields good results; however, dumbbell-shaped neurinomas often present challenges for complete resection. Some extensive surgical approaches for complete removal have been reported to lead to severe complications. Therefore, the surgical strategy for dumbbell-shaped neurinomas is controversial. METHODS: Twelve patients with dumbbell-shaped neurinomas were surgically treated in our hospital over 5 years. We adopted a posterior approach to remove the intracanalicular portion of the neurinomas as completely as possible, intentionally leaving the foraminal portion unresected to prevent bony and vascular insult. We investigated the postoperative surgical results and complications and the regrowth rate of the remnant lesions. RESULTS: Postoperative residual tumours were identified in 6 of the 12 patients. The perioperative neurological findings between the two groups were almost the same. The recurrence rate was low. Severe surgery-related complications occurred in only one patient with mild and temporary motor weakness. CONCLUSION: Our strategy demonstrated low rates of recurrence and complications compared with those accompanying the extensive alternative approaches that have been reported previously. Our case series showed that subtotal removal of dumbbell-shaped neurinomas using a posterior approach is a safer, more effective, and more minimally invasive treatment.

Isolated primary malignant lymphoma arising from the optic chiasm.

Isolated primary malignant lymphoma rarely arises from the anterior visual pathway. A 59-year-old previously healthy man presented with progressive, painless, bilateral visual disturbance. Neurological imaging revealed an enhancing mass arising from the optic chiasm. Open biopsy was carried out under monitoring of visual evoked potentials and a histopathological diagnosis of diffuse large B-cell lymphoma was made. As systemic examination did not show any evidence of systemic lymphoma, we concluded that this patient had an isolated primary malignant lymphoma at the anterior visual pathway.

Early changes in tissue perfusion after tissue plasminogen activator administration in hyperacute ischemic stroke: initial experiences with arterial spin labeling perfusion magnetic resonance imaging.

Cerebral perfusion monitoring is an important component of hyperacute stroke treatment. Arterial spin labeling (ASL) perfusion magnetic resonance (MR) imaging provides a noninvasive method of cerebral perfusion observation. Rapid changes in cerebral perfusion were demonstrated in two patients admitted one hour after onset of hyperacute stroke who underwent recombinant tissue plasminogen activator (rt-PA) treatment. Serial MR images and ASL images were taken on admission and after rt-PA administration. Cerebral blood flow (CBF) values were obtained using the CBF workstation and analysis software. Interpretable ASL images were taken in both patients. Perfusion deficits were consistent with symptoms and/or MR angiography imaging abnormalities. Delayed arterial transit effect was present in one patient; serial imaging showed improvement of CBF after rt-PA treatment in both patients. ASL perfusion MR imaging can provide rapid noninvasive multislice imaging in hyperacute ischemic stroke, and can depict early perfusion deficit and quantify regional CBF concomitantly.