Bainan Xu

Microsurgical management of large and giant paraclinoid aneurysms

BACKGROUND Because of the complex topographic anatomical relationship between vascular, dural and bone structures, paraclinoid aneurysms, especially those of larger size, remain a great challenge for vascular neurosurgeons. We present our microneurosurgical experience of 51 consecutive patients with large and giant paraclinoid aneurysms to scrutinize our personal strategies related to surgical treatment. METHODS Fifty-one patients with large or giant paraclinoid underwent micorneurosurgical aneurysm treatment. Operative strategies were planned according to preoperative state-of-the-art imaging studies, and a pterional-transsylvian approach was routinely used. Proximal control of the internal carotid artery (ICA) was achieved by exposure of the cervical portion of the vessel. Intraoperative electroencephalogram and somatosensory evoked potential monitoring, indocyanine green (ICG) videoangiography and/or microvascular Doppler ultrasonography (MDU) were regularly used. A postoperative digital subtraction angiography or computed tomography angiography was performed to verify the efficacy of treatment. RESULTS Forty-three large and giant paraclinoid aneurysm necks (84%) were directly clipped, seven unclippable aneurysms (14%) were trapped with extra-intracranial high-flow revascularization, and one aneurysm (2%) was treated with only ICA proximal Hunterian ligation. Two patients (4%) died in the early postoperative period. In 84% of the patients, the Glasgow Outcome Scale score was 4 or 5 at discharge. At the 6-month follow-up examination, the Rankin Outcome Scale score was 0-2 in 90% of patients. CONCLUSIONS Temporary parent vessel occlusion, retrograde suction decompression, endoaneurysmectomy, parent vessel clip reconstruction, and bypass vascular anastomosis are essential techniques to treat complex paraclinoid aneurysms. The combined use of electrophysiological monitoring, MDU, intraoperative ICG videoangiography, and endoscopy can substantially improve microsurgical outcome.

Integration of diffusion tensor-based arcuate fasciculus fibre navigation and intraoperative MRI into glioma surgery

This study was designed to evaluate the feasibility and efficacy of diffusion tensor-based arcuate fasciculus (AF) fibre navigation in combination with 1.5-Tesla (1.5-T) intraoperative MRI (iMRI) for the resection of gliomas involving eloquent language fibre tracts (AF tracts). Twenty patients with AF tract-involved gliomas in the dominant hemisphere were prospectively enrolled. The patients were divided into two groups. The normal group included nine patients with preoperative intact language function, while the aphasia group consisted of 11 patients who presented with different levels of conduction aphasia. The AF tractography results were integrated into three-dimensional (3D) datasets used for neuronavigation, and their course was superimposed onto the surgical field during glioma resection. The iMRI was used to compensate for the effects of brain shift and to evaluate the extent of resection. Fibre tract visualisation provided a quick and intuitive overview of the displaced course of the AF in 3D space and the surgical field under a microscope. At a 3-month to 6-month follow-up, only two patients from the normal group suffered exacerbated language deficits due to tumour recurrence. Meanwhile, language function in all patients in the aphasia group had improved. Therefore, AF neuronavigation, combined with 1.5 T iMRI, is a feasible method of maximising resection and minimising language deficits when removing gliomas that involve the AF.

Comparison of the Tada Formula With Software Slicer Precise and Low-Cost Method for Volume Assessment of Intracerebral Hematoma

Background and Purpose— The Tada (ABC/2) formula has been used widely for volume assessment of intracerebral hematoma. However, the formula is crude for irregularly shaped hematoma. We aimed to compare the accuracy of the ABC/2 formula with open source software Slicer. Methods— Computed tomographic images of 294 patients with spontaneous intracerebral hematoma were collected. Hematoma volumes were assessed with the ABC/2 formula and calculated with software 3D Slicer. Results of these 2 methods were compared with regard to hematoma size and shape. Results— The estimated hematoma volume was 58.41±37.83 cm3 using the ABC/2 formula, compared with 50.38±31.93 cm3 with 3D Slicer (mean percentage deviation, 16.38±9.15%). When allocate patients into groups according to hematoma size, the mean estimation error were 3.24 cm3 (17.72%), 5.85 cm3 (13.72%), and 15.14 cm3 (17.48%) for groups 1, 2, and 3, respectively. When divided by shape, estimation error was 3.33 cm3 (9.76%), 7.19 cm3 (18.37%), and 29.39 cm3 (39.12%) for regular, irregular, and multilobular hematomas. Conclusions— There is significant estimation error using the ABC/2 formula to calculate hematoma volume. Compared with hematoma size, estimation error is more significantly associated with hematoma shape.

Intraoperative MRI with integrated functional neuronavigation-guided resection of supratentorial cavernous malformations in eloquent brain areas.

Between March 2009 and January 2010, 36 patients with 38 supratentorial cavernous malformations in eloquent brain areas underwent surgery with the aid of intraoperative MRI (iMRI), functional neuronavigation, and electrocorticography (ECoG). To optimize outcomes, the hemosiderin-stained tissue surrounding the lesion in addition to the cavernous malformation itself (lesion) was microsurgically removed, leaving behind only small areas adjacent to, or overlapping with, functional areas. According to the Zabramski classification, there were 13 type I lesions, which all underwent total resection. There were 25 type II or III lesions with a surrounding hypointense rim, and all of these lesions were completely removed; the surrounding hypointense rims were completely removed in 15 patients and partially removed in 10. No new neurologic disorders occurred postoperatively. Twenty patients had preoperative epileptic seizures, nine of whom were refractory to treatment. During follow-up, seizure outcome was assessed using the Engel classification, and 11 patients with non-refractory epilepsy had a class I outcome. Of the nine patients with refractory epilepsy, seven (77.8%) had a class I outcome, one (11.1%) had a class II outcome, and one (11.1%) had a class III outcome.

The diagnostic performance of magnetic resonance spectroscopy in differentiating high-from low-grade gliomas: A systematic review and meta-analysis

ObjectiveMagnetic resonance spectroscopy (MRS) is a powerful tool for preoperative grading of gliomas. We performed a meta-analysis to evaluate the diagnostic performance of MRS in differentiating high-grade gliomas (HGGs) from low-grade gliomas (LGGs).MethodsPubMed and Embase databases were systematically searched for relevant studies of glioma grading assessed by MRS through 27 March 2015. Based on the data from eligible studies, pooled sensitivity, specificity, diagnostic odds ratio and areas under summary receiver operating characteristic curve (SROC) of different metabolite ratios were obtained.ResultsThirty articles comprising a total sample size of 1228 patients were included in our meta-analysis. Quantitative synthesis of studies showed that the pooled sensitivity/specificity of Cho/Cr, Cho/NAA and NAA/Cr ratios was 0.75/0.60, 0.80/0.76 and 0.71/0.70, respectively. The area under the curve (AUC) of the SROC was 0.83, 0.87 and 0.78, respectively.ConclusionsMRS demonstrated moderate diagnostic performance in distinguishing HGGs from LGGs using tumoural metabolite ratios including Cho/Cr, Cho/NAA and NAA/Cr. Although there was no significant difference in AUC between Cho/Cr and Cho/NAA groups, Cho/NAA ratio showed higher sensitivity and specificity than Cho/Cr ratio and NAA/Cr ratio. We suggest that MRS should combine other advanced imaging techniques to improve diagnostic accuracy in differentiating HGGs from LGGs.Key points• MRS has moderate diagnostic performance in distinguishing HGGs from LGGs.• There is no significant difference in AUC between Cho/Cr and Cho/NAA ratios.• Cho/NAA ratio is superior to NAA/Cr ratio.• Cho/NAA ratio shows higher sensitivity and specificity than Cho/Cr and NAA/Cr ratios.• MRS should combine other advanced imaging techniques to improve diagnostic accuracy.

The retrosigmoid approach to petroclival meningioma surgery

Petroclival meningiomas are technically challenging lesions. The authors retrospectively analyzed their experience between 2000 and 2010 in 82 patients with petroclival meningioma to evaluate changes in management strategy. A total of 42 patients (51%) were treated via the retrosigmoid approach. The patients received postoperative neurological and neuroradiological follow-up. The maximum diameter of the tumors ranged from 1.5 cm to 6.5 cm (mean, 3.8 cm). Gross total resection (Simpson Grade II) was achieved in 27 patients (64%), subtotal resection (Simpson Grade III) in 11 (26%), and partial removal (Simpson Grade IV) in four (9.5%). Ten patients (24%) had new neurological deficits or worsening of pre-existing deficits. One patient (2%) died because of brainstem dysfunction after surgery. The retrosigmoid approach is suitable for treatment of selected petroclival meningioma if the main part of the tumor is located in the posterior fossa in the cerebellopontine angle and the low clivus, and only a minor part of the tumor extends to the posterior wall of the cavernous sinus. This approach provides a low degree of surgical difficulty and a low complication rate.

In vivo visualization of the facial nerve in patients with acoustic neuroma using diffusion tensor imaging–based fiber tracking

OBJECTIVE Preoperative determination of the facial nerve (FN) course is essential to preserving its function. Neither regular preoperative imaging examination nor intraoperative electrophysiological monitoring is able to determine the exact position of the FN. The diffusion tensor imaging-based fiber tracking (DTI-FT) technique has been widely used for the preoperative noninvasive visualization of the neural fasciculus in the white matter of brain. However, further studies are required to establish its role in the preoperative visualization of the FN in acoustic neuroma surgery. The object of this study is to evaluate the feasibility of using DTI-FT to visualize the FN. METHODS Data from 15 patients with acoustic neuromas were collected using 3-T MRI. The visualized FN course and its position relative to the tumors were determined using DTI-FT with 3D Slicer software. The preoperative visualization results of FN tracking were verified using microscopic observation and electrophysiological monitoring during microsurgery. RESULTS Preoperative visualization of the FN using DTI-FT was observed in 93.3% of the patients. However, in 92.9% of the patients, the FN visualization results were consistent with the actual surgery. CONCLUSIONS DTI-FT, in combination with intraoperative FN electrophysiological monitoring, demonstrated improved FN preservation in patients with acoustic neuroma. FN visualization mainly included the facial-vestibular nerve complex of the FN and vestibular nerve.

Intraoperative MRI for optimizing electrode placement for deep brain stimulation of the subthalamic nucleus in Parkinson disease

OBJECT The degree of clinical improvement achieved by deep brain stimulation (DBS) is largely dependent on the accuracy of lead placement. This study reports on the evaluation of intraoperative MRI (iMRI) for adjusting deviated electrodes to the accurate anatomical position during DBS surgery and acute intracranial changes. METHODS Two hundred and six DBS electrodes were implanted in the subthalamic nucleus (STN) in 110 patients with Parkinson disease. All patients underwent iMRI after implantation to define the accuracy of lead placement. Fifty-six DBS electrode positions in 35 patients deviated from the center of the STN, according to the result of the initial postplacement iMRI scans. Thus, we adjusted the electrode positions for placement in the center of the STN and verified this by means of second or third iMRI scans. Recording was performed in adjusted parameters in the x-, y-, and z-axes. RESULTS Fifty-six (27%) of 206 DBS electrodes were adjusted as guided by iMRI. Electrode position was adjusted on the basis of iMRI 62 times. The sum of target coordinate adjustment was -0.5 mm in the x-axis, -4 mm in the y-axis, and 15.5 mm in the z-axis; the total of distance adjustment was 74.5 mm in the x-axis, 88 mm in the y-axis, and 42.5 mm in the z-axis. After adjustment with the help of iMRI, all electrodes were located in the center of the STN. Intraoperative MRI revealed 2 intraparenchymal hemorrhages in 2 patients, brain shift in all patients, and leads penetrating the lateral ventricle in 3 patients. CONCLUSIONS The iMRI technique can guide surgeons as they adjust deviated electrodes to improve the accuracy of implanting the electrodes into the correct anatomical position. The iMRI technique can also immediately demonstrate acute changes such as hemorrhage and brain shift during DBS surgery.

Surgical management of large and giant cavernous sinus hemangiomas

Cavernous sinus hemangiomas (CSH) are rare vascular tumors within the cavernous sinus. Gamma Knife radiosurgery (GKS) is less effective for large and giant CSH than for smaller ones. In one of the largest single-institution series reported thus far, we present 22 patients with large (3-4 cm-diameter, six patients) and giant (>4 cm, 16 patients) CSH treated surgically between 1994 and 2011. We also review related reports published since 1999 and further compare the treatment outcomes of surgery and radiosurgery. In the present study, a modified Dolencs epidural approach was performed in 18 patients and the intradural approach was used in four. Gross total or near-total resection was achieved in 18 patients, subtotal resection was achieved in three patients and partial resection was achieved in one patient. Postoperative ophthalmoparesis occurred in seven patients (two improved, four unchanged to preoperative, one new deficit), and decreased visual acuity occurred in one patient. The reviewed literature and our experience suggest that surgical treatment of large and giant CSH is a reasonable option. A relatively low postoperative morbidity can be achieved with minimal disturbance of cranial nerve (CN) III, particularly with early localization and preservation of CN VI. GKS could be an adjunct treatment for residual tumor.

Effectiveness of endoscopic surgery for supratentorial hypertensive intracerebral hemorrhage: a comparison with craniotomy

OBJECTIVE The goal of this study was to investigate the effectiveness and practicality of endoscopic surgery for treatment of supratentorial hypertensive intracerebral hemorrhage (HICH) compared with traditional craniotomy. METHODS The authors retrospectively analyzed 151 consecutive patients who were operated on for treatment of supratentorial HICH between January 2009 and June 2014 in the Department of Neurosurgery at Chinese PLA General Hospital. Patients were separated into an endoscopy group (82 cases) and a craniotomy group (69 cases), depending on the surgery they received. The hematoma evacuation rate was calculated using 3D Slicer software to measure the hematoma volume. Comparisons of operative time, intraoperative blood loss, Glasgow Coma Scale score 1 week after surgery, hospitalization time, and modified Rankin Scale score 6 months after surgery were also made between these groups. RESULTS There was no statistically significant difference in preoperative data between the endoscopy group and the craniotomy group (p > 0.05). The hematoma evacuation rate was 90.5% ± 6.5% in the endoscopy group and 82.3% ± 8.6% in the craniotomy group, which was statistically significant (p < 0.01). The operative time was 1.6 ± 0.7 hours in the endoscopy group and 5.2 ± 1.8 hours in the craniotomy group (p < 0.01). The intraoperative blood loss was 91.4 ± 93.1 ml in the endoscopy group and 605.6 ± 602.3 ml in the craniotomy group (p < 0.01). The 1-week postoperative Glasgow Coma Scale score was 11.5 ± 2.9 in the endoscopy group and 8.3 ± 3.8 in the craniotomy group (p < 0.01). The hospital stay was 11.6 ± 6.9 days in the endoscopy group and 13.2 ± 7.9 days in the craniotomy group (p < 0.05). The mean modified Rankin Scale score 6 months after surgery was 3.2 ± 1.5 in the endoscopy group and 4.1 ± 1.9 in the craniotomy group (p < 0.01). Patients had better recovery in the endoscopy group than in the craniotomy group. Data are expressed as the mean ± SD. CONCLUSIONS Compared with traditional craniotomy, endoscopic surgery was more effective, less invasive, and may have improved the prognoses of patients with supratentorial HICH. Endoscopic surgery is a promising method for treatment of supratentorial HICH. With the development of endoscope technology, endoscopic evacuation will become more widely used in the clinic. Prospective randomized controlled trials are needed.