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Surgical manifestations of thoracic arachnoid pathology

Thoracic arachnoid pathology

J Neurosurg Spine 20:30–40, 2014

Various pathologies involving the thoracic arachnoid mater uniformly manifest as thoracic myelopathy and may present a significant management dilemma. The authors undertook this study to assess outcome in cases of thoracic myelopathy due to thoracic arachnoid pathology.

Methods. The authors have cared for and followed 28 patients with thoracic myelopathy from thoracic arachnoid pathology over the last 17 years. A chart review and contemporary follow-up of these patients was performed and outcomes were reported.

Results. Patients with thoracic myelopathy from thoracic arachnoid pathology often have improvement in their condition after surgical decompression/detethering procedures. While not universal, patients in this series had improvement in mJOA scores at 1 year after surgery (p = 0.0001) and at last follow-up (p = 0.04). Results indicated that across a wide variety of pathologies the extent of thoracic spinal cord involvement is a predictor of the disease course and outcome. Comparison of the group of patients with cord involvement limited to 2 vertebral segments (short-segment pathology) versus the group with cord tethering of more than 2 segments (long-segment pathology) showed that patients in the short-segment group more frequently had ventral or dorsal arachnoid bands (p = 0.003), more frequently had signal change in the cord on MRI (p = 0.02), and less frequently presented with a syrinx (p = 0.02), and a smaller percentage of patients in this group underwent reoperation (p = 0.02). While patients with shortsegment pathology typically improved after a single operative intervention, patients with long-segment pathology typically improved after multiple operations, frequently for CSF diversion.

Conclusions. Thoracic arachnoid pathology causing thoracic cord dysfunction and myelopathy is varied, has multiple etiologies, and can be difficult to treat over the long term. Surgical management, when indicated, is case specific. Serial long-term follow-up is essential to document enduring clinical and radiographic success.

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Transpetrosal approach for challenging craniopharyngiomas

Transpetrosal approach for challenging craniopharyngiomas

J Neurosurg 120:1–11, 2014

Retrochiasmatic craniopharyngiomas are surgically challenging tumors. Retrochiasmatic craniopharyngiomas with complicated conditions such as large diameter, major calcification, or significant extension to the third ventricle or posterior fossa present surgical challenges; moreover, recurrent retrochiasmatic craniopharyngiomas are particularly formidable challenges. Although the transpetrosal approach to retrochiasmatic craniopharyngiomas published by Hakuba in 1985 can provide unique advantageous exposure of the retrochiasmatic area to allow safe neurovascular dissection and facilitate radical tumor removal, the procedure is viewed as complicated and time consuming and has a high risk of damaging hearing functions. The authors have modified Hakuba’s technique to minimize petrosectomy and reduce surgical complications and have applied this modified approach to retrochiasmatic craniopharyngiomas with complicated conditions. In this study, the authors describe their technique and surgical outcomes to elucidate the role of this modified transpetrosal approach for retrochiasmatic craniopharyngiomas with complicated conditions. This is the first study to report surgical outcomes of the transpetrosal approach for retrochiasmatic craniopharyngiomas.

Methods. Between 1999 and 2011, the minimum anterior and posterior combined (MAPC) transpetrosal approach, which is a modification of Hakuba’s transpetrosal approach, was applied in 16 cases of retrochiasmatic craniopharyngiomas with complicated conditions. Eight cases were recurrent tumors, 4 had previously received radiotherapy, 11 had a large diameter, 10 had large calcification, 15 had superior extension of the tumor into the third ventricle, and 10 had a posterior extension of the tumor that compressed the midbrain and pons. In all 16 patients, more than 2 of these complicated conditions were present. The follow-up duration ranged from 0.8 to 12.5 years (mean 5.3 years). Surgical outcomes assessed were the extent of resection, surgical complications, visual function, endocrinological status, and neuropsychological function. Five-year and 10-year recurrence-free survival rates were also calculated.

Results. Gross-total or near-total resection was achieved in 15 cases (93.8%). Facial nerve function was completely maintained in all 16 patients. Serviceable hearing was preserved in 15 cases (93.8%). Visual function improved in 13 out of 14 cases (92.9%) that had visual disturbance before surgery. None of the patients experienced deterioration of their visual function. Twelve cases had endocrinological deficit and received hormonal replacement before surgery. New endocrinological deficit occurred in 2 cases (12.5%). Neuropsychological function was maintained in 14 cases (87.5%) and improved in 1 case (6.3%). One case that had received previous conventional radiotherapy treatment showed a gradual decline in neuropsychological function. The 5-year and 10-year recurrence-free survival rates were both 86.5%.

Conclusions. The authors obtained good results by using the MAPC transpetrosal approach for the removal of retrochiasmatic craniopharyngiomas with complicated conditions. The MAPC transpetrosal approach should be considered as a therapeutic option for selected cases of retrochiasmatic craniopharyngiomas with complicated conditions.

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Combined endovascular and surgical treatment of fusiform aneurysms of the basilar artery

Combined endovascular and surgical treatment of fusiform aneurysms of the basilar artery- technical note

Acta Neurochir (2014) 156:53–61

To present the combined treatment of fusiform basilar artery aneurysms consisting of a surgical posterior fossa decompressive craniectomy and ventriculoperitoneal (VP) shunt operation at the same sitting, before the endovascular procedure with telescopic stenting of the aneurysmatic vessel segment in four cases.

Methods Combined treatment involving surgical procedure consisting of ventriculoperitoneal shunt placement for hydrocephalus and an occipital bone craniectomy and C1 vertebrae posterior laminectomy to decompress the posterior fossa in the same session. After surgery, the patients were loaded with acetylsalicylic acid and clopidogrel, and then the endovascular treatment was performed.

Results All of the procedures were performed successfully without technical difficulty. The patients tolerated the procedures well and all cases showed remodelling with the overlapping stent technique. The patients were discharged home with baseline neurological situation and computed tomography (CT) angiography was performed at the 3rd month.

Conclusion This technique is a safer endovascular approach to treating symptomatic fusiform basilar artery aneurysms by protecting patients from both the haemorrhagic complications of anticoagulant therapy and thrombotic complications due to the interruption of anticoagulant therapy, while treating the hydrocephalus and compression by surgical means.

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The callosal angle measured on MRI as a predictor of outcome in idiopathic normal-pressure hydrocephalus

The callosal angle measured on MRI as a predictor of outcome in idiopathic normal-pressure hydrocephalus

J Neurosurg 120:178–184, 2014

Different neuroimaging biomarkers have been studied to find a tool for prediction of response to CSF shunting in idiopathic normal-pressure hydrocephalus (iNPH). The callosal angle (CA) has been described as useful in discriminating iNPH from ventricular dilation secondary to atrophy. However, the usefulness of the CA as a prognostic tool for the selection of shunt candidates among patients with iNPH is unclear. The aim of this study was to compare the CA in shunt responders with that in nonresponders and clarify whether the CA can serve as a predictor of the outcome.

Methods. Preoperative MRI brain scans were evaluated in 109 patients who had undergone shunt surgery for iNPH during 2006–2010. Multiplanar reconstruction was performed interactively to obtain a coronal image through the posterior commissure, perpendicular to the anterior-posterior commissure plane. The CA was measured as the angle between the lateral ventricles on the coronal image. The patients were examined clinically before surgery and at 12 months postoperatively.

Results. Shunt responders had a significantly smaller mean preoperative CA compared with nonresponders: 59° (95% CI 56°–63°) versus 68° (95% CI 61°–75°) (p < 0.05). A CA cutoff value of 63° showed the best prognostic accuracy.

Conclusions. The preoperative CA is smaller in patients whose condition improves after shunt surgery and may be a useful tool in the selection of shunt candidates among patients with iNPH.

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Cognard Type V Intracranial Dural Arteriovenous Shunt

Cognard Type V Intracranial Dural Arteriovenous Shunt

Neurosurgery 74:E135–E142, 2014

Prompt diagnosis of intracranial dural arteriovenous shunt (DAVS) with spinal venous drainage, classified as Cognard type V, is difficult. We investigated the angiographic and magnetic resonance imaging (MRI) characteristics of Cognard type V DAVS to determine the reason for the difficulty in early diagnosis.

CLINICAL PRESENTATION: We systematically reviewed 54 published and 3 new cases of Cognard type V DAVS. The pattern of venous drainage was classified on the basis of relative dominance of the anterior and posterior spinal veins with the use of angiograms. T2-weighted sagittal MRIs were used to detect signal flow voids of enlarged spinal veins. Types of venous drainage were determined in 49 of the 57 cases. Twentyeight and 8 cases showed a dominance of anterior and posterior spinal venous drainage, respectively. In 13 cases, venous drainage was equally distributed through the anterior and posterior spinal veins. Of 41 cases with an abnormally dilated anterior spinal vein, MRIs were available for 25 cases. Signal flow voids of enlarged anterior spinal veins were detected in 9 cases (36.0%), whereas dilatation of the posterior spinal veins was apparent in 9 of 16 cases (56.3%). Overall, MRI detected enlargement of either anterior or posterior spinal veins in 15 of 41 cases (36.6%).

CONCLUSION: In Cognard type V DAVS, anterior venous drainage is dominant. Because the anterior spinal veins are located subpially, flow voids are less prominent on sagittal T2-weighted MRI. This may lead to difficulties in diagnosing. Evaluation with MR angiography may compensate for these limitations.

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Insular low-grade glioma and postoperative seizure outcome

Surgery for insular low-grade glioma- predictors of postoperative seizure outcome

J Neurosurg 120:12–23, 2014

Although a number of recent studies on the surgical treatment of insular low-grade glioma (LGG) have demonstrated that aggressive resection leads to increased overall patient survival and decreased malignant progression, less attention has been given to the results with respect to tumor-related epilepsy. The aim of this investigation was to evaluate the impact of volumetric, histological, and intraoperative neurophysiological factors on seizure outcome in patients with insular LGG.

Methods. The authors evaluated predictors of seizure outcome with special emphasis on both the extent of tumor resection (EOR) and the tumor’s infiltrative pattern quantified by computing the difference between the preoperative T2- and T1-weighted MR images (DVT2T1) in 52 patients with preoperative drug-resistant epilepsy.

Results. The 12-month postoperative seizure outcome (Engel class) was as follows: seizure free (Class I), 67.31%; rare seizures (Class II), 7.69%; meaningful seizure improvement (Class III), 15.38%; and no improvement or worsening (Class IV), 9.62%. Poor seizure control was more common in patients with a longer preoperative seizure history (p < 0.002) and higher frequency of seizures (p = 0.008). Better seizure control was achieved in cases with EOR ≥ 90% (p < 0.001) and DVT2T1 < 30 cm3 (p < 0.001). In the final model, DVT2T1 proved to be the strongest independent predictor of seizure outcome in insular LGG patients (p < 0.0001).

Conclusions. No or little postoperative seizure improvement occurs mainly in cases with a prevalent infiltrative tumor growth pattern, expressed by high DVT2T1 values, which consequently reflects a smaller EOR.

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Schmorl’s nodes: current pathophysiological, diagnostic, and therapeutic paradigms

Schmorl's nodes

Neurosurg Rev (2014) 37:39–46

Schmorl’s nodes were first described by the pathologist Christian Schmorl in 1927 as a herniation of the nucleus pulposus through the cartilaginous and bony endplate into the vertebral body. Although such lesions present most commonly as incidental findings in asymptomatic patients (or in patients with back or radicular pain due to other etiology), there have been several reports emphasizing the deleterious effects of the inflammatory response and endplate changes elicited by the herniation of for such reasons, Schmorl’s nodes have been occasionally implicated in the etiology of chronic axial pain as well as in pathological osteoporotic fractures.

In this article, a thorough literature review about the most relevant historical studies on Schmorl’s nodes previously published is performed. Furthermore, the authors provide an overview about the recent advances in basic science research on the pathophysiology of such lesions, as well as on current diagnostic and therapeutic paradigms.

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The value of immediate postoperative MR imaging following endoscopic endonasal pituitary surgery

The value of immediate postoperative MR imaging following endoscopic endonasal pituitary surgery

Acta Neurochir (2014) 156:133–140

Although the value of early MR imaging has been justified for microscopic transphenoidal surgery, there is no literature evaluating immediate postoperative MR imaging following endoscopic endonasal resection of pituitary adenomas. We hypothesized that MRI of the pituitary gland performed on the first postoperative day is just as effective at detecting residual disease and/or reconstruction materials as the MRI at 3 months following surgery.

Methods We retrospectively evaluated 102 consecutive patients who underwent endoscopic endonasal surgery for presumed pituitary adenomas. Sixty-four patients met the inclusion criteria with immediate and 3 months MR imaging. Imaging was evaluated by two sets of observers. The following parameters were assessed: enhancement pattern of the pituitary gland, pituitary stalk, nodular enhancement (residual tumor) or linear enhancement (non-tumoral) and residual reconstruction/packing materials.

Results Gross total resection of the tumors with no cavernous sinus involvement was achieved in 49 out of 52 (94 %) patients. Eleven out of 12 remaining patients with cavernous sinus invasion had residual cavernous sinus component visible on both immediate and 3 month MR imaging. The pituitary gland, position of stalk, and nasoseptal flap could be identified on both post-operative MRIs in all patients. The sensitivity and specificity for residual tumor detection on immediate MRI was 100 % and 97.9 %, respectively. The kappa index evaluating interobserver agreement for identification of residual tumor and packing/reconstruction material on immediate MR was 0.83 and 0.72 indicating near perfect and substantial agreement, respectively.

Conclusion Immediate MR imaging performed following endoscopic endonasal resection of pituitary lesions provides accurate and reliable information regarding the presence of residual tumor compared to reconstruction and packing materials.

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Early promising results for the endoscopic surgical treatment of Cushing’s disease

Endoscopic treatment of Cushing's disease

Neurosurg Rev (2014) 37:105–114

High levels of endogenous cortisol due to Cushing’s disease cause significant mortality and morbidity. Treatment of Cushing’s disease is challenging. For many years, transsphenoidal microsurgical resection of the adenoma has been the treatment of choice. However, recently, neuroendoscope has taken its place in the neurosurgeon’s armamentarium, and the endoscopic transsphenoidal resection of pituitary tumors has become a familiar approach.

Our aim was to present the results of pure endoscopic surgery in the treatment of corticotropinomas for comparison with the results of previous endoscopic and microsurgical series.

We present a retrospective analysis of 90 patients with diagnosis of Cushing’s disease who were operated between 2006 and 2012. Among 90 patients, a total of 81 (90.0%) had a remission (28 out of 29 macroadenomas (96.6 %) and 53 out of 61 microadenoma patients (86.9 %)). Of note is that 66 out of 69 (95.7 %) primary patients (i.e., those who were operated in our center) and 15 out of 21 (71.4 %) patients previously operated in other centers reached a hypo/eucortisolemic state. A remission rate comparable with previous endoscopic series was achieved. In nine patients, it was not possible to achieve remission at all. On the other hand, only four of our cases (5.6%) had a recurrence, andwith reoperation, all of these patients entered a re-remission. To our knowledge, our series is the largest series studying endoscopically operated adrenocorticotropic hormone-secreting adenomas. Our results suggest that the endoscopic approach has opened a new avenue in the treatment of Cushing’s disease, previously a therapeutic challenge for both the clinician and the neurosurgeon.

Endoscopic approach in the treatment of Cushing’s disease is clearly better for patients because of its low morbidity rates and short duration of hospital stay. On the other hand, long-term follow-up of our patients will show whether these favorable observations will persist.

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Diffusion Tensor Imaging of the Spinal Cord

Diffusion_Tensor_Imaging_of_the_Spinal_Cord__

Neurosurgery 74:1–8, 2014

Diffusion tensor imaging (DTI) provides a measure of the directional diffusion of water molecules in tissues. The measurement of DTI indexes within the spinal cord provides a quantitative assessment of neural damage in various spinal cord pathologies.

DTI studies in animal models of spinal cord injury indicate that DTI is a reliable imaging technique with important histological and functional correlates. These studies demonstrate that DTI is a noninvasive marker of microstructural change within the spinal cord.

In human studies, spinal cord DTI shows definite changes in subjects with acute and chronic spinal cord injury, as well as cervical spondylotic myelopathy. Interestingly, changes in DTI indexes are visualized in regions of the cord, which appear normal on conventional magnetic resonance imaging and are remote from the site of cord compression.

Spinal cord DTI provides data that can help us understand underlying microstructural changes within the cord and assist in prognostication and planning of therapies. In this article, we review the use of DTI to investigate spinal cord pathology in animals and humans and describe advances in this technique that establish DTI as a promising biomarker for spinal cord disorders.

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Anatomy and morphology of giant aneurysms

Giant aneurysms

Acta Neurochir (2014) 156:1–10

Giant intracranial aneurysms are rare and heterogeneous lesions with complex vascular anatomy. The aim of this retrospective study was to provide a comprehensive description of the anatomical features of giant aneurysms.

Methods We identified 125 patients with 129 giant aneurysms (≥25 mm) who were treated between 1987 and 2007 at the Department of Neurosurgery of Helsinki University Central Hospital (HUCH). All the imaging studies and medical records were reviewed for relevant information.

Results The distribution of the giant aneurysms among regions was as follows: internal carotid artery (ICA) 39 %, middle cerebral artery (MCA) 32 %, vertebrobasilar and posterior cerebral artery (VB-PCA) region 25 %, and anterior cerebral artery (ACA) including the anterior communicating artery 5%. The cavernous ICA segment (n =21, 16 %) and the MCA bifurcation (n =25, 19 %) were the most frequent specific locations. Half (n =11) of all fusiform aneurysms were found in the VB-PCA region. As many as 41 % of the giant MCA aneurysms were ruptured. Major anatomic variations were found in three (2 %) and multiple giant aneurysms in three (2 %) patients.Wall calcification was noted in 24 % and intraluminal thrombosis in 33 % of ruptured giant aneurysms (n =42).

Conclusions The majority of giant aneurysms are located in the ICA and MCA regions, while the ACA region is an exceptional site. The MCA region is the most common site for ruptured giant aneurysms. Associated anatomic variations and the multiplicity of giant aneurysms are a rare finding.

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Frontobasal interhemispheric approach for large suprasellar craniopharyngiomas

Frontobasal interhemispheric approach for large superasellar craniopharyngiomas

Acta Neurochir (2014) 156:123–131

Large suprasellar craniopharyngiomas are surgically challenging. The aim of our study was to explore the therapeutic efficacy of the frontobasal interhemispheric approach for these lesions.

Methods Twenty-nine consecutive adult patients with large suprasellar craniopharyngiomas (diameter>4 cm) who underwent the frontobasal interhemispheric approach were retrospectively evaluated. Surgical and clinical outcomes were analyzed.

Results Gross total removal was achieved in 23 cases (79.3 %) and subtotal removal in 6 cases (20.7 %). The mean follow-up period was 76.5±33.2 months (range, 12-132 months). Twenty-four patients (82.7 %) had improvement of the visual impairment score (VIS) after surgery. VIS was unchanged in five patients (17.3 %), and no patients experienced visual deterioration. Among 23 patients who had preoperative hypopituitarism, 8 (34.8 %) had an improvement. Postoperative new or aggravated hypopituitarism was observed in four patients (13.8 %). Permanent diabetes insipidus was observed in ten patients (34.4 %). Postoperative anosmia occurred in two earlier cases (6.9 %). There was no intracranial infection or cerebrospinal fluid fistula. At last follow-up, >9 % BMI gain was observed in 34.5 % of patients, and 65.5 % of patients returned to work. Four patients (13.8 %) suffered recurrence.

Conclusion Although the frontobasal interhemispheric approach has some disadvantages, it provides ideal access to the suprasellar region and the third ventricle with limited brain retraction. The surgically visible angle is adequate; thus, vital structures can be better protected. For large suprasellar craniopharyngiomas, the benefits of this approach can outweigh its potential risks.

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Functional outcome and postoperative complications after the microsurgical removal of large vestibular schwannomas via the retrosigmoid approach: a meta-analysis

vestibular-schwannoma

Neurosurg Rev (2014) 37:15–21

For large (≥30 mm) or giant (≥40 mm) vestibular schwannomas (VSs) for which microsurgical removal is the main treatment option, complete tumour resection and the preservation of acceptable facial nerve function can be safely and successfully achieved via the retrosigmoid approach.

We performed a meta-analysis to provide a reliable estimate of functional outcome and postoperative complications for patients treated surgically for large VSs. We conducted a comprehensive search in Pubmed, Embase and the Chinese National Knowledge Infrastructure (CNKI) databases to identify publications that included only patients in whom the VSs were >3.0 cm in maximal diameter and microsurgically removed by a retrosigmoid approach. Pooled estimates of proportions with corresponding 95 % confidence intervals were calculated using the Freeman–Tukey double arcsine transformation. This meta-analysis revealed that the pooled proportion of gross total resections was 79.1 % (95 % CI, 64.2–90.8 %; I2=95.4 %). By combining microsurgical techniques with continuous electrophysiological monitoring, the anatomical preservation of the facial nerve at the end of surgery was achieved in 88.8 % (95 % CI, 83.6–93.2 %; I2=76.1 %) of the patients. The pooled proportion of good postoperative facial nerve function (House–Brackmann (HB) grades I–II) was 62.9 % (95 % CI, 50.0–74.9 %; I2=91.1 %). Cerebrospinal fluid leakage was reported in 7.8 % (95 % CI, 4.8–11.4 %; I2=49.8 %) of the patients. The mortality rate was 0.87 % (95 % CI, 0.22–1.78 %; I2=4.9 %).

Our meta-analysis revealed that for large VSs, very favourable results can be obtained using the retrosigmoid approach with minimal mortality, especially with respect to anatomical and functional facial nerve preservation.

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Anatomical variants of the basal vein of Rosenthal: prevalence in idiopathic subarachnoid hemorrhage

Anatomical variants of the basal vein of Rosenthal- prevalence in idiopathic subarachnoid hemorrhage

Acta Neurochir (2014) 156:45–51

Spontaneous, non traumatic subarachnoid hemorrhage (SAH) is a significant clinical problem that occurs most commonly as a result of aneurysm rupture. In approximately 15 % of cases, nor aneurysm or other vascular malformation can be identified by cerebral angiography as origin of the hemorrhage, and these are commonly defined as idiopathic SAH (ISAH). Because of the negative angiography, limited extension of the bleeding with prevalent prepontine pattern and the benign prognosis, the venous causes has been preferred rather than the arterial ones. In the literature recent studies have suggested a possible contribution by primitive variants of Basal vein of Rosenthal (BVR) in its the pathogenesis of ISAH, commonly grouped according Watanabe classification (type A, B and C). In this paper we evaluated the prevalence of anatomical variants of BVR in ISAH.

Methods Venous drainage at angiography was retrospectively analyzed in 40 patients with ISAH and in 40 with unruptured aneurysms as controls.

Results and conclusions Previous studies displayed a significant prevalence of BVR type C variants in ISAH. Conversely in our study we recognized variant B as prevalent, in which the BVR bifurcates to drain anteriorly into the uncal vein and posteriorly into the Galenic system. Similarly to variant C (in which the BVR drains via perimesencephalic “bridging” veins into cavernous, sphenoparietal, petrosal sinus or directly into transverse sinus) also variant B might be subjected to those stress mechanisms and intrinsic system ‘fragility’ and for reasons yet to determine, sets off a consequent hemorrhage with clinical and radiological features typical of ISAH.

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Intraspinal Stem Cell Transplantation in Amyotrophic Lateral Sclerosis

Intraspinal Stem Cell Transplantation in Amyotrophic Lateral Sclerosis

Neurosurgery 74:77–87, 2014

The first US Food and Drug Administration approved clinical trial for a stem cell-based treatment of amyotrophic lateral sclerosis has now been completed.

OBJECTIVE: Primary aims assessed the safety of a direct microinjection-based technique and the toxicity of neural stem cell transplantation to the ventral horn of the cervical and thoracolumbar spinal cord. Results from thoracolumbar-only microinjection groups have been previously published. Cervical and cervical plus thoracolumbar microinjection group perioperative morbidity results are presented.

METHODS: Eighteen microinjection procedures (n = 12 thoracolumbar [T10/11], n = 6 cervical [C3-5]) delivered NSI-566RSC (Neuralstem, Inc), a human neural stem cell, to 15 patients in 5 cohorts. Each injection series comprised 5 injections of 10 mL at 4-mm intervals. The patients in group A (n = 6) were nonambulatory and received unilateral (n = 3) or bilateral (n = 3) thoracolumbar microinjections. The patients in groups B to E were ambulatory and received either unilateral (group B, n = 3) or bilateral (group C, n = 3) thoracolumbarmicroinjection. Group D and E patients received unilateral cervical (group D, n = 3) or cervical plus bilateral thoracolumbar microinjection (group E, n = 3).

RESULTS: Unilateral cervical (group D, n = 3) and cervical plus thoracolumbar (group E, n = 3) microinjections to the ventral horn have been completed in ambulatory patients. One patient developed a postoperative kyphotic deformity prompting completion of a laminoplasty in subsequent patients. Another required reoperation for wound dehiscence and infection. The solitary patient with bulbar amyotrophic lateral sclerosis required perioperative reintubation.

CONCLUSION: Delivery of a cellular payload to the cervical or thoracolumbar spinal cord was well tolerated by the spinal cord in this vulnerable population. This encouraging finding supports consideration of this delivery approach for neurodegenerative, oncologic, and traumatic spinal cord afflictions.

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Endoscopic third ventriculostomy: can we predict success during surgery?

ETV-1

Neurosurg Rev (2014) 37:89–97

Endoscopic third ventriculostomy (ETV) is widely used as an alternative technique for hydrocephalus treatment. ETV success or failure may be influenced by numerous factors. In this study, we have analyzed preoperative and intraoperative risk factors and suggest an intraoperative scale to predict etV failure.

Fifty-one patients (27 adults and 24 children) underwent an etV at Carlos Haya University Hospital, Malaga. Intraoperative video records were assessed and the following intraoperative findings were recorded: (1) abnormal ventricular anatomy, (2) intraoperative incident, (3) Liliequist membrane opening in a second endoscopic maneuver, (4) thickened or scarred membranes in the subarachnoid space, (5) absence or “weakness” of pulsation of third ventricle floor at etV completion, and (6) floppy premammillary membrane that needs edge coagulation. An intraoperative scale ranging from 0 to 6 points was performed.

A significant relation was found between a higher result on the prognosis scale and etV failure (p <0.0001). An absence or weakness of pulsation of the third ventricle floor at etV completion was significantly related to etV failure (p <0.0001).

The presence of thickened or scarred membranes in the subarachnoid space was significantly related to etV failure (p <0.04) as well as the Liliequist membrane opening in a second endoscopic maneuver (p <0.008). Intraoperative factors should be taken into account for prediction of etV success. More studies with larger case series are needed to determine the influence of all intraoperative factors over etV success

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Real-Time Atlas-Based Stereotactic Neuronavigation

Real-Time Atlas-Based Stereotactic Neuronavigation

Neurosurgery 74:128–134, 2014

Surgery for tumors in eloquent brain faces immense challenges when attempting to maximize resection and avoid neurological deficits.

OBJECTIVE: In order to give the surgeon real-time atlas-based anatomic information linked to the patient’s anatomy, we developed a software-based interface between deformable anatomic templates (DATs) and an intraoperative navigation system.

METHODS: Magnetic resonance imaging (MRI), diffusion tensor imaging, and/or functional MRI were performed on 3 patients preoperatively for the purposes of tumor resection by the use of neuronavigation. The DAT was registered to the patients’ navigation coordinate system and utilized coordinates from the navigation system during surgery. This provided the surgeon with a list of proximal anatomic and functional structures and a real-time image of the atlas at that location fused to the patient’s MRI. The clinical feasibility of this approach was evaluated during the resection of 3 eloquent tumors (right postcentral gyrus, left inferior frontal gyrus, and left occipital cuneus gyrus).

RESULTS: Tumor resection was performed successfully in all 3 patients. With the use of the coordinates from the navigation system, anatomic and functional structures and their distances were visualized interactively during tumor resection by using the DAT.

CONCLUSION: This is a proof of concept that an interactive atlas-based navigation can provide detailed anatomic and functional information that supplements MRI, diffusion tensor imaging, and functional MRI. The atlas-based navigation generated distances to important anatomic structures from the navigation probe tip. It can be used to guide direct electrical stimulation and highlight areas to avoid during tumor resection.

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Focused opening of the sylvian fissure for microsurgical management of MCA aneurysms

Focused opening of the sylvian fissure for microsurgical management of MCA aneurysms

Acta Neurochir (2014) 156:17–25

A wide sylvian opening, with either a proximal or distal start, has been standard for microsurgical management of middle cerebral artery (MCA) aneurysms. However, extensive sylvian dissection is potentially associated with increased incidence of iatrogenic injury to the brain and neurovascular structures. The aim of the present study was to describe the technique of focused opening of the sylvian fissure for microsurgical management of MCA aneurysms with additional tips on handling difficulties which may be encountered with this technique.

Method A 3D image-based anatomic orientation, clipping field–focused surgical planning, slack brain, and high magnification are the basic requirements for this approach. A 10– 15 mm sylvian opening is placed so that it allows safe access and a good surgical view of the MCA aneurysm clipping field. Under proximal control of the MCA, the aneurysm neck can be dissected and clipped effectively and safely, in this small surgical field.

Results The presented technique has been developed and refined by the senior author during the surgery of 1,097 aneurysms over the last 13 years. It has proved to be safe, and effective for clipping of both ruptured and unruptured MCA aneurysms. Its greatest advantages are a shorter operative time and less brain and vessel manipulation compared to more extensive approaches.

Conclusion The focused sylvian opening is a less-invasive alternative to the classical wide sylvian opening for the microsurgical management of most MCA aneurysms.

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Computational Fluid Dynamic Analysis of Intracranial Aneurysmal Bleb Formation

Computational Fluid Dynamic Analysis of Intracranial Aneurysmal Bleb Formation

Neurosurgery 73:1061–1069, 2013

The management of unruptured aneurysms is controversial, with the decision to treat influenced by aneurysm characteristics including size and morphology. Aneurysmal bleb formation is thought to be associated with an increased risk of rupture.

OBJECTIVE: To correlate computational fluid dynamic (CFD) indices with bleb formation.

METHODS: Anatomic models were constructed from 3-dimensional rotational angiography data in 27 patients with cerebral aneurysms harboring a single bleb. Additional models representing the aneurysm before bleb formation were constructed by digitally removing the bleb. We characterized hemodynamic features of models both with and without the blebs using CFDs. Flow structure, wall shear stress (WSS), pressure, and oscillatory shear index (OSI) were analyzed.

RESULTS: There was a statistically significant association between bleb location at or adjacent to the point of maximal WSS (74%, P = .019), irrespective of rupture status. Aneurysmal blebs were related to the inflow or outflow jet in 89% of cases (P < .001), whereas 11% were unrelated. Maximal wall pressure and OSI were not significantly related to bleb location. The bleb region attained a lower WSS after its formation in 96% of cases (P < .001) and was also lower than the average aneurysm WSS in 86% of cases (P < .001).

CONCLUSION: Cerebral aneurysm blebs generally form at or adjacent to the point of maximal WSS and are aligned with major flow structures. Wall pressure and OSI do not contribute to determining bleb location. The measurement of WSS using CFD models may potentially predict bleb formation and thus improve the assessment of rupture risk in unruptured aneurysms.

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Management of tuberculum and diaphragma sellae meningiomas

TSM, DSM

Neurosurg Focus 35 (6):E7, 2013

Tuberculum sellae meningiomas (TSMs) and diaphragma sellae meningiomas (DSMs) are challenging lesions to treat due to their proximity to neurovascular structures.

Methods. The authors reviewed the medical records of patients who underwent surgical excision of TSMs and DSMs from 1990 to 2013. They also describe the technical strategies used to minimize injury to the optic apparatus, vascular structures, and pituitary stalk.

Results. Twenty-four patients with TSM and 6 patients with DSM were included in the study. Seventy percent of the tumors were large (≥ 5 cm). The pterional approach was employed in most cases. Optic canal involvement was observed in 4 patients. Twenty-one patients (70%) had visual dysfunction before surgery. At follow-up (median 18 months), visual improvement was noted in 10 (47.6%) of 21 patients. Gross-total excision was achieved in 22 patients (91.6%) with TSM and 5 (83.3%) with DSM. At last follow-up, 28 patients (93.3%) had a Glasgow Outcome Scale score of 5. There were no deaths in this series.

Conclusions. Tuberculum and diaphragma sellae meningiomas present a unique subset of tumors due to their location. They can be safely excised with minimal morbidity and mortality using microsurgical techniques. Attention to technical details during surgery leads to greater respectability and superior visual outcome.

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