Author: cba

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A basic model for training of microscopic and endoscopic transsphenoidal pituitary surgery: the Egghead

A basic model for training of microscopic and endoscopic transsphenoidal pituitary surgery- the Egghead

Acta Neurochir (2015) 157:1771–1777

Transsphenoidal endoscopic surgery has gained popularity in the last 2 decades and is becoming a standard technique for resection of pituitary adenomas. In contrast to their ENT colleagues, neurosurgical residents have practically no endoscopic experience when they reach the training stage for transsphenoidal procedures.

We have developed an affordable method for repetitive training in endoscopic (and microscopic) work in a narrow channel, allowing training of the basic movements needed for resection of pituitary adenoma.

Methods In collaboration with colleagues in the ENT Department, Cantonal Hospital St. Gall, and the Technical University of Zurich, a three-dimensional model of the nasal cavity was developed and patented. The Egghead model consists of a 3D synthetic reconstruction of the head nasal cavity and sphenoid sinus. A boiled egg represents the sella. For validation, 17 neurosurgical residents from the Department of Neurosurgery, University Hospital of Basel, and Department of Neurosurgery, Cantonal Hospital of St. Gall, St. Gall, Switzerland, and two experts performed a standardized procedure mimicking a transsphenoidal pituitary procedure by dissecting a corridor to the egg yolk and resecting it, respecting the surrounding egg white. This procedure was performed under both microscopic and video-endoscopic visualization. A score for the precision and speed of the surgical performance was developed and used.

Results The model allows repetitive training of the resection of the egg yolk under sparing of the egg white after careful opening of the shell. The validation data showed a steeper learning curve using the endoscopic technique than performing the same task using the microscope. After three repetitions, the quality of resection was better with the endoscopic technique.

Conclusions Our model, the Egghead, is affordable, offers tactile feedback and allows infinite repetitions in basic training for pituitary surgery. It can be used for training of advanced neurosurgical residents, who thus far have very few possibilities of acquiring endoscopic experience.

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Interdigitated craniotomy: a simple technique to fix a bone flap with only a single plate

interdigitated craniotomy

J Neurosurg 123:1055–1058, 2015

In pterional craniotomy, fixation plates cause artifacts on postoperative radiological images; furthermore, they often disfigure the scalp in hairless areas.

The authors describe a simple technique to fix a cranial bone flap with only a single plate underneath the temporalis muscle in an area with hair, rather than using a plate in a hairless area.

The key to this technique is to cut the anterior site of the bone flap at alternate angles on the cut surface. Interdigitation between the bone flap and skull enables single-plate fixation in the area with hair, which reduces artifacts on postoperative radiological images and provides excellent postoperative cosmetic results.

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Treatment strategies for dissecting aneurysms of the posterior cerebral artery

Treatment strategies for dissecting aneurysms of the posterior cerebral arteryActa Neurochir (2015) 157:1623–1632

We conducted a systematic review of the literature to evaluate the safety and efficacy of surgical treatment of previously coiled aneurysms.

Methods A comprehensive review of the literature for studies on surgical treatment of previously coiled aneurysms was conducted. For each study, the following data were extracted: patient demographics, initial clinical status, location and size of aneurysms, time interval between initial/last endovascular procedure and surgery, surgical indications, and microsurgical technique.We performed subgroup analyses to compare direct clipping versus coil removal and clipping versus parent vessel occlusion, early (<4 weeks post-coiling) versus late surgery and anterior versus posterior circulation.

Results Twenty-six studies with 466 patients and 471 intracranial aneurysms were included. All of the studies were retrospective and non-comparative case-series. Patients undergoing direct clipping had lower perioperative morbidity (5.0 %, 95%CI=2.6–7.4 %) when compared to those undergoing coil removal and clipping (11.1 %, 95 % CI=5.3–17.0 %) or parent vessel occlusion (13.1 %, 95%CI=4.6–21.6 %) (p=0.05). Patients receiving early surgery (<4 weeks post-coiling) had significantly lower rates of good neurological outcome (77.1 %, 95 % CI=69.3–84.8 %) when compared to those undergoing late surgery (92.1 %, 95 % CI=89.0–95.2 %) (p<0.01). There were higher rates of long-term neurological morbidity in the posterior circulation group (23.1 vs. 4.7 %, p<0.01) as well as long-term neurological mortality (4.4 vs. 2.8 %, p<0.01).

Conclusions Our meta-analysis suggests that surgical treatment is safe and effective. Our data indicate that aneurysms that are amenable to direct clipping have superior outcomes. Late surgery was also associated with better clinical outcomes. Surgery of recurrent posterior circulation aneurysms was associated with high rates of morbidity and mortality. Given the characteristics of the included studies, the quality of evidence of this meta-analysis is limited.

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A Systematic Review of the Treatment of Geriatric Type II Odontoid Fractures

Type II Odontoid Fractures

Neurosurgery 77:S6–S14, 2015

Odontoid fractures are the most common cervical spine fracture in the geriatric population; however, the treatment of type II odontoid fractures in this age group is controversial.

OBJECTIVE: To compare the short-term (<3 months) mortality, long-term (≥12 months) mortality, and complication rates of patients >60 years of age with a type II odontoid fracture managed either operatively or nonoperatively.

METHODS: We performed a systematic review of literature published between January 1, 2000, and February 1, 2015, related to the treatment of type II odontoid fractures in patients .60 years of age. An analysis of short-term mortality, long-term mortality, and the occurrence of complications was performed.

RESULTS: A total of 452 articles were identified, of which 21 articles with 1233 patients met the inclusion criteria. Short-term mortality (odds ratio, 0.43; 95% confidence interval, 0.30-0.63) and long-term mortality (odds ratio, 0.47; 95% confidence interval, 0.34-0.64) were lower in patients who underwent surgical treatment than in those who had nonsurgical treatment, and there were no significant differences in the rate of complications (odds ratio, 1.01; 95% confidence interval, 0.63-1.63). Surgical approach (posterior vs anterior) showed no significant difference in mortality or complication rate. Similarly, no difference in mortality or complication rate was identified with hard collar or a halo orthosis immobilization.

CONCLUSION: The current literature suggests that well-selected patients >60 years of age undergoing surgical treatment for a type II odontoid fracture have a decreased risk of short-term and long-term mortality without an increase in the risk of complications.

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Unskilled unawareness and the learning curve in robotic spine surgery

SpineAssist™ robot system

Acta Neurochir (2015) 157:1819–1823

Robotic assistance for the placement of pedicle screws has been established as a safe technique. Nonetheless rare instances of screw misplacement have been reported.The aim of the present retrospective study is to assess whether experience and time affect the accuracy of screws placed with the help of the SpineAssist™ robot system.

Methods Postoperative computed tomography (CT) scans of 258 patients requiring thoracolumbar pedicle screw instrumentation from 2008 to 2013 were reviewed. Overall, 13 surgeons performed the surgeries. A pedicle breach of >3 mm was graded as a misplacement. Surgeons were dichotomised into an early and experienced period in increments of five surgeries.

Results In 258 surgeries, 1,265 pedicle screws were placed with the aid of the robot system. Overall, 1,217 screws (96.2 %) were graded as acceptable. When displayed by surgeon, the development of percent misplacement rates peaked between 5 and 25 surgeries in 12 of 13 surgeons. The overall misplacement rate in the first five surgeries was 2.4%(6/245). The misplacement rate rose to 6.3 % between 11 and 15 surgeries (10/158; p=0.20), and reached a significant peak between 16 and 20 surgeries with a rate of 7.1 % (8/112; p= 0.03). Afterwards, misplacement rates declined.

Conclusions A major peak in screw inaccuracies occurred between cases 10 and 20, and a second, smaller one at about 40 surgeries. One potential explanation could be a transition from decreased supervision (unskilled but aware) to increased confidence of a surgeon (unskilled but unaware) who adopts this new technique prior to mastering it (skilled). We therefore advocate ensuring competent supervision for new surgeons at least during the first 25 procedures of robotic spine surgery to optimise the accuracy of robot-assisted pedicle screws.

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Pathological response of cavernous malformations following radiosurgery

Pathological response of cavernous malformations following radiosurgery

J Neurosurg 123:938–944, 2015

Stereotactic radiosurgery (SRS) is a therapeutic option for repeatedly hemorrhagic cavernous malformations (CMs) located in areas deemed to be high risk for resection. During the latency period of 2 or more years after SRS, recurrent hemorrhage remains a persistent risk until the obliterative process has finished. The pathological response to SRS has been studied in relatively few patients. The authors of the present study aimed to gain insight into the effect of SRS on CM and to propose possible mechanisms leading to recurrent hemorrhages following SRS.

Methods During a 13-year interval between 2001 and 2013, bleeding recurred in 9 patients with CMs that had been treated using Gamma Knife surgery at the authors’ institution. Microsurgical removal was subsequently performed in 5 of these patients, who had recurrent hemorrhages between 4 months and 7 years after SRS. Specimens from 4 patients were available for analysis and used for this report.

Results Histopathological analysis demonstrated that vascular sclerosis develops as early as 4 months after SRS. In the samples from 2 to 7 years after SRS, sclerotic vessels were prominent, but there were also vessels with incomplete sclerosis as well as some foci of neovascularization.

Conclusions: Recurrent bleeding after SRS for CM could be related to incomplete sclerosis of the vessels, but neovascularization may also play a role.

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Higher-Resolution Magnetic Resonance Elastography in Meningiomas to Determine Intratumoral Consistency

Higher-Resolution Magnetic Resonance Elastography in Meningiomas to Determine Intratumoral Consistency

Neurosurgery 77:653–659, 2015

Magnetic resonance elastography (MRE) analyzes shear wave movement through tissue to determine stiffness. In a prior study, measurements with firstgeneration brain MRE techniques correlated with intraoperative observations of overall meningioma stiffness.

OBJECTIVE: To evaluate the diagnostic accuracy of a higher-resolution MRE technique to preoperatively detect intratumoral variations compared with surgeon assessment.

METHODS: Fifteen meningiomas in 14 patients underwent MRE. Tumors with regions of distinctly different stiffness were considered heterogeneous. Intratumoral portions were considered hard if there was a significant area ≥6 kPa. A 5-point scale graded intraoperative consistency. A durometer semiquantitatively measured surgical specimen hardness. Statistics included x2, sensitivity, specificity, positive and negative predicative values, and Spearman rank correlation coefficient.

RESULTS: For MRE and surgery, 9 (60%) and 7 (47%) tumors were homogeneous, 6 (40%) and 8 (53%) tumors were heterogeneous, 6 (40%) and 10 (67%) tumors had hard portions, and 14 (93%) and 12 (80%) tumors had soft portions, respectively. MRE sensitivity, specificity, and positive and negative predictive values were as follows: for heterogeneity, 75%, 100%, 100%, and 87%; for hardness, 60%, 100%, 100%, and 56%; and for softness, 100%, 33%, 86%, and 100%. Overall, 10 tumors (67%) matched well with MRE and intraoperative consistency and correlated between intraoperative observations (P = .02) and durometer readings (P = .03). Tumor size ≤3.5 cm or vascular tumors were more likely to be inconsistent (P < .05).

CONCLUSION: MRE was excellent at ruling in heterogeneity with hard portions but less effective in ruling out heterogeneity and hard portions, particularly in tumors more vascular or ≤3.5 cm. MRE is the first technology capable of prospectively evaluating intratumoral stiffness and, with further refinement, will likely prove useful in preoperative planning.

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Safety and efficacy of microsurgical treatment of previously coiled aneurysms: a systematic review and meta-analysis

coiledaneurysm

Acta Neurochir (2015) 157:1623–1632

We conducted a systematic review of the literature to evaluate the safety and efficacy of surgical treatment of previously coiled aneurysms.

Methods A comprehensive review of the literature for studies on surgical treatment of previously coiled aneurysms was conducted. For each study, the following data were extracted: patient demographics, initial clinical status, location and size of aneurysms, time interval between initial/last endovascular procedure and surgery, surgical indications, and microsurgical technique. We performed subgroup analyses to compare direct clipping versus coil removal and clipping versus parent vessel occlusion, early (<4 weeks post-coiling) versus late surgery and anterior versus posterior circulation.

Results Twenty-six studies with 466 patients and 471 intracranial aneurysms were included. All of the studies were retrospective and non-comparative case-series. Patients undergoing direct clipping had lower perioperative morbidity (5.0 %, 95%CI=2.6–7.4 %) when compared to those undergoing coil removal and clipping (11.1 %, 95 % CI=5.3–17.0 %) or parent vessel occlusion (13.1 %, 95%CI=4.6–21.6 %) (p=0.05). Patients receiving early surgery (<4 weeks post-coiling) had significantly lower rates of good neurological outcome (77.1 %, 95 % CI=69.3–84.8 %) when compared to those undergoing late surgery (92.1 %, 95 % CI=89.0–95.2 %) (p<0.01). There were higher rates of long-term neurological morbidity in the posterior circulation group (23.1 vs. 4.7 %, p<0.01) as well as long-term neurological mortality (4.4 vs. 2.8 %, p<0.01).

Conclusions Our meta-analysis suggests that surgical treatment is safe and effective. Our data indicate that aneurysms that are amenable to direct clipping have superior outcomes. Late surgery was also associated with better clinical outcomes. Surgery of recurrent posterior circulation aneurysms was associated with high rates of morbidity and mortality. Given the characteristics of the included studies, the quality of evidence of this meta-analysis is limited.

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Microrecording and stereotactic biopsy of brain tumors

Microrecording and image-guided stereotactic biopsy of deep-seated brain tumors

J Neurosurg 123:978–988, 2015

Image-guided stereotactic brain tumor biopsy cannot easily obtain samples of small deep-seated tumor or selectively sample the most viable region of malignant tumor. Image-guided stereotactic biopsy in combination with depth microrecording was evaluated to solve such problems.

Methods Operative records, MRI findings, and pathological specimens were evaluated in 12 patients with small deep-seated brain tumor, in which image-guided stereotactic biopsy was performed with the aid of depth microrecording. The tumors were located in the caudate nucleus (1 patient), thalamus (7 patients), midbrain (2 patients), and cortex (2 patients). Surgery was performed with a frameless stereotactic system in 3 patients and with a frame-based stereotactic system in 9 patients. Microrecording was performed to study the electrical activities along the trajectory in the deep brain structures and the tumor. The correlations were studied between the electrophysiological, MRI, and pathological findings. Thirty-two patients with surface or large brain tumor were also studied, in whom image-guided stereotactic biopsy without microrecording was performed.

Results The diagnostic yield in the group with microrecording was 100% (low-grade glioma 4, high-grade glioma 4, diffuse large B-cell lymphoma 3, and germinoma 1), which was comparable to 93.8% in the group without microrecording. The postoperative complication rate was as low as that of the conventional image-guided method without using microelectrode recording, and the mortality rate was 0%, although the target lesions were small and deep-seated in all cases. Depth microrecording revealed disappearance of neural activity in the tumor regardless of the tumor type. Neural activity began to decrease from 6.3 ± 4.5 mm (mean ± SD) above the point of complete disappearance along the trajectory. Burst discharges were observed in 6 of the 12 cases, from 3 ± 1.4 mm above the point of decrease of neural activity. Injury discharges were often found at 0.5–1 mm along the trajectory between the area of decreased and disappeared neural activity. Close correlations between electrophysiological, MRI, and histological findings could be found in some cases.

Conclusions Image-guided stereotactic biopsy performed using depth microrecording was safe, it provided accurate positional information in real time, and it could distinguish the tumor from brain structures during surgery. Moreover, this technique has potential for studying the epileptogenicity of the brain tumor.

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Transzygomatic approach with anteriorly limited inferior temporal gyrectomy for large medial tentorial meningiomas

Transzygomatic approach with anteriorly limited inferior temporal gyrectomy for large medial tentorial meningiomas

Acta Neurochir (2015) 157:1747–1756

Tentorial meningiomas near the middle third of the medial tentorial edge with supratentorial extension are usually removed via the subtemporal approach. This approach, however, may not be practical, especially for huge tumors extending to the posterior subtemporal space. This study describes the use of the transzygomatic approach with anteriorly limited inferior temporal gyrectomy (TZ-AITG) to remove these large tumors.

Methods Between 2008 and 2012, five patients with symptomatic tentorial meningiomas (median diameter, 5.2 cm; range, 4.0–5.7 cm) near the middle third of the medial tentorial edge with supratentorial extension underwent TZAITG, consisting of zygomatic osteotomy, low-positioned craniotomy, and resection of the inferior temporal gyrus around 4 cm from the tip.

Results Tumors were completely resected in all patients. Postoperatively, none had a newly developed neurological morbidity, and none died. Of three patients with preoperative hemianopia, two showed improvement and one remained stationary. One patient with preoperative hemiparesis recovered completely. All patients returned to their normal activities during the follow-up period. Surgical morbidities included epidural hematoma and chronic subdural hematoma in one patient each, with both requiring evacuation.

Conclusions TZ-AITG may be a good alternative to the subtemporal approach for large tentorial meningiomas near the middle third of the medial tentorial edge. TZ-AITG provides access to the lesions and visualization of the middle fossa, facilitating early feeder control while minimizing brain retraction, thus reducing potential injury to the vein of Labbé. TZ-AITG is also safe and feasible in minimizing neurological compromise.

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Posterior interhemispheric transfalcine transprecuneus approach for microsurgical resection of periatrial lesions

posterior interhemispheric transfalcine transprecuneus approach

J Neurosurg 123:1045–1054, 2015

Surgical exposure of the peritrigonal or periatrial region has been challenging due to the depth of the region and overlying important functional cortices and white matter tracts. The authors demonstrate the operative feasibility of a contralateral posterior interhemispheric transfalcine transprecuneus approach (PITTA) to this region and present a series of patients treated via this operative route. Methods Fourteen consecutive patients underwent the PITTA and were included in this study. Pre- and postoperative clinical and radiological data points were retrospectively collected. Complications and extent of resection were reviewed.

Results The mean age of patients at the time of surgery was 39 years (range 11–64 years). Six of the 14 patients were female. The mean duration of follow-up was 4.6 months (range 0.5–19.6 months). Pathology included 6 arteriovenous malformations, 4 gliomas, 2 meningiomas, 1 metastatic lesion, and 1 gray matter heterotopia. Based on the results shown on postoperative MRI, 1 lesion (7%) was intentionally subtotally resected, but ≥ 95% resection was achieved in all others (93%) and gross-total resection was accomplished in 7 (54%) of 13. One patient (7%) experienced a temporary approach-related complication. At last follow-up, 1 patient (7%) had died due to complications of his underlying malignancy unrelated to his cranial surgery, 2 (14%) demonstrated a Glasgow Outcome Scale (GOS) score of 4, and 11 (79%) manifested a GOS score of 5.

Conclusions Based on this patient series, the contralateral PITTA potentially offers numerous advantages, including a wider, safer operative corridor, minimal need for ipsilateral brain manipulation, and better intraoperative navigation and working angles.

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Management of the Elderly With Vertebral Compression Fractures

Management of the Elderly With Vertebral Compression Fractures

Neurosurgery 77:S33–S45, 2015

Vertebral compression fractures (VCFs) are the most common type of fracture secondary to osteoporosis. These fractures are associated with significant rates of morbidity and mortality and annual direct medical expenditures of more than $1 billion in the United States. Although many patients will respond favorably to nonsurgical care of their VCF, contemporary natural history data suggest that more than 40% of patients may fail to achieve significant pain relief within 12 months of symptom onset. As a result, percutaneous vertebral augmentation is often used to hasten symptom resolution and return of function. However, controversy regarding the role of kyphoplasty and vertebroplasty in the treatment of symptomatic VCFs exists.

The purposes of this review are (1) to outline the epidemiology of VCFs as well as the physical morbidity and economic impact of these injuries, (2) to familiarize the reader with the best available evidence surrounding the operative and nonoperative treatment of VCFs, and (3) to examine the literature pertaining to the cost-effectiveness of surgical management of VCFs with the overarching goal of helping physicians make informed decisions regarding symptomatic VCF treatment.

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Microsurgical resection of an intramedullary glomus arteriovenous malformation in the high cervical spinal cord

Microsurgical resection of an intramedullary glomus arteriovenous malformation in the high cervical spinal cord

Acta Neurochir (2015) 157:1659–1664

Spinal intramedullary arteriovenous malformations (AVMs) fed by an anterior spinal artery are surgically challenging vascular lesions.

Method We herein presented microsurgical resection techniques for an intramedullary glomus AVM located in the lateral part of the high cervical spinal cord with an operative video.

These techniques included (1) a lateral suboccipital approach via cervical hemilaminectomy in the lateral position; (2) retrograde dissection of the AVM located between the spinal tracts; (3) coagulation and division of multiple narrow sulcal branches of the anterior spinal artery.

Conclusion Patients who underwent these techniques achieved good outcomes with minimal bleeding and morbidity.

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Can Preoperative Imaging Predict Tumor Involvement of the Anterior Clinoid in Clinoid Region Meningiomas?

Can Preoperative Imaging Predict Tumor Involvement of the Anterior Clinoid in Clinoid Region Meningiomas?

Neurosurgery 77:525–530, 2015

Anterior clinoid region meningiomas may infiltrate the bone over which they arise, therefore requiring an anterior clinoidectomy to achieve a Simpson grade 1 resection. A clinoidectomy, however, is not without risks.

OBJECTIVE: We performed a study of diagnostic accuracy investigating whether preoperative imaging could predict tumor involvement of the clinoid, and thereby tailor the degree of bony removal.

METHODS: Patients having undergone resection of a clinoid region meningioma between 2001 and 2011 were identified. Included in further analysis were those patients in whom a clinoidectomy was performed with subsequent pathologically confirmed presence or absence of tumor in the clinoid process on decalcified specimens. Two neuroradiologists, blinded to pathology results, independently reviewed available preoperative imaging and stated whether or not they anticipated the clinoid to be involved by tumor. Interobserver agreement and the ability to accurately predict tumor involvement of the clinoid were then analyzed.

RESULTS: Sixty-two patients were included in the final analysis. Interobserver agreement was 100%. Sensitivity and specificity of preoperative imaging to predict tumor involvement was 89% and 52%, respectively, with positive and negative likelihood ratios of 1.85 and 0.20. Positive and negative predictive values were 73% and 76%, respectively.

CONCLUSION: Preoperative imaging of clinoid region meningiomas can accurately predict the presence or absence of tumor involvement of the clinoid in only approximately 75% of cases. In light of the fact that a quarter of patients with radiographically negative clinoids will have tumor present on pathological analysis, we recommend a clinoidectomy for all clinoid region meningiomas.

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Minimally Invasive Spinal Surgery in the Elderly: Does It Make Sense?

Minimally Invasive Spinal Surgery in the Elderly- Does It Make Sense

Neurosurgery 77:S108–S115, 2015

Lumbar degenerative disease can have varied pathoanatomy, with stenosis, spondylolisthesis, and scoliosis contributing to significant pain and disability. Among appropriately selected patients, surgical intervention can treat both back pain and leg pain and improve quality of life in a cost-effective manner with an acceptable safety profile. The evolution of minimally invasive surgical (MIS) techniques offers the potential to decrease the physiological impact of surgery and to improve the complication profile while achieving the same spine surgical objectives. The utility of such techniques among elderly patients >65 years of age has not been rigorously evaluated, and this systematic review sought to define the utility and safety of MIS spinal surgery for decompression, interbody fusion, and deformity correction in this population.

Review of 2 studies for MIS lumbar decompression reveals that the majority of elderly patients exhibit significant improvements in pain (change in visual analog score for leg pain, 3.4 points) and disability (change in Oswestry Disability Index, 19 points), with inadvertent durotomy in 3% of patients. Review of 4 studies for MIS lumbar interbody fusion reveals robust improvement in pain (change in visual analog score for leg pain, 3.4 points; change in visual analog score for back pain, 7.2 points), with inadvertent durotomy in 5% of patients.

Narrative review was performed for adult degenerative deformity correction, revealing that MIS techniques are feasible for managing such patients with acceptable rates of osseous union and complication. On the basis of largely low-quality, retrospective evidence, we recommend that elderly patients should not be excluded from MIS interventions for symptomatic lumbar degenerative spinal disease.

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Feasibility of radiological markers in idiopathic normal pressure hydrocephalus

Feasibility of radiological markers in idiopathic normal pressure hydrocephalus

Acta Neurochir (2015) 157:1709–1719

Various radiological markers have been proposed for diagnostics in idiopathic normal pressure hydrocephalus (iNPH).We examined the usefulness of radiological markers in the diagnostics and prediction of shunt response in iNPH.

Method In this retrospective cohort study, we evaluated brain CTor MRI scans of 390 patients with suspected iNPH. Based on a 24-h intraventricular pressure monitoring session, patients were classified into a non-NPH (n=161) or probable iNPH (n=229) group. Volumes of cerebrospinal fluid compartments (lateral ventricles, sylvian and suprasylvian subarachnoid spaces and basal cisterns) were visually assessed. Disproportionally enlarged subarachnoid spaces, flow void, white matter changes, medial temporal lobe atrophy and focally dilated sulci were evaluated. Moreover, we measured quantitative markers: Evans’ index (EI), the modified cella media index, mean width of the temporal horns and callosal angle.

Results iNPH was more likely in patients with severe volumetric disproportion between the suprasylvian and sylvian subarachnoid spaces than in those without disproportion (OR 7.5, CI 95 % 4.0–14.1, P<0.0001). Mild disproportion (OR 2.6, CI 95 % 1.4–4.6, P=0.001) and narrow temporal horns (OR per 1mm0.91, CI 95%0.84–0.98, P=0.014)were also associated with an iNPH diagnosis. Other radiological markers had little association with the iNPH diagnosis in the final combined multivariate model. Interestingly, EI was higher in non-NPH than iNPH patients (0.40 vs. 0.38, P= 0.039). Preoperative radiological markers were not associated with shunt response.

Conclusions Visually evaluated disproportion was the most useful radiological marker in iNPH diagnostics. Narrower temporal horns also supported an iNPH diagnosis, possibly since atrophy was more pronounced in the non-NPH than iNPH group.

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Endoscopic hematoma evacuation for acute and subacute subdural hematoma in elderly patients

Endoscopic hematoma evacuation for acute and subacute subdural hematoma in elderly patients

J Neurosurg 123:1065–1069, 2015

Endoscopic surgery was performed for acute or subacute subdural hematoma (SDH), and its effectiveness and safety in elderly patients were evaluated.

Methods Between September 2007 and November 2013, endoscopic surgery was performed in 11 elderly patients with acute SDH (8 patients) and subacute SDH (3 patients). The criteria for surgery were as follows: 1) the presence of clinical symptoms; 2) age older than 70 years; 3) no brain injury (intracerebral hematoma, brain contusion); 4) absence of an enlarging SDH; and 5) no high risk of bleeding. Hematoma evacuation was performed with a 4-mm rigid endoscope with a 0° lens and a malleable irrigation suction cannula.

Results Endoscopic surgery was performed under local anesthesia. The mean age of the patients was 82.6 years (range 73–91 years). There were 5 female and 6 male patients. The mean preoperative Glasgow Coma Scale score was 12, and 5 patients had been receiving antithrombotic drug therapy. The mean operation time was 85 minutes. Only 1 patient had rebleeding, and reoperation with the same technique was performed uneventfully in this individual. A total of 7 patients had a good recovery (modified Rankin Scale Score 0–2) at discharge.

Conclusions Endoscopic hematoma evacuation of acute and subacute SDH is a safe and effective method of clot removal that minimizes operative complications. This technique may be a less invasive method for treating elderly patients with acute and subacute SDHs.

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Subcortical anatomy as an anatomical and functional landmark in insulo-opercular gliomas

Subcortical anatomy as an anatomical and functional landmark in insulo-opercular gliomas

J Neurosurg 123:1081–1092, 2015

Little attention has been given to the functional challenges of the insular approach to the resection of gliomas, despite the potential damage of essential neural networks that underlie the insula. The object of this study is to analyze the subcortical anatomy of the insular region when infiltrated by gliomas, and compare it with the normal anatomy in nontumoral hemispheres.

Methods Ten postmortem human hemispheres were dissected, with isolation of the inferior fronto-occipital fasciculus (IFOF) and the uncinate fasciculus. Probabilistic diffusion tensor imaging (DTI) tractography was used to analyze the subcortical anatomy of the insular region in 10 healthy volunteers and in 22 patients with insular Grade II and Grade III gliomas. The subcortical anatomy of the insular region in these 22 insular gliomas was compared with the normal anatomy in 20 nontumoral hemispheres.

Results In tumoral hemispheres, the distances between the peri-insular sulci and the lateral surface of the IFOF and uncinate fasciculus were enlarged (p < 0.05). Also in tumoral hemispheres, the IFOF was identified in 10 (90.9%) of 11 patients with an extent of resection less than 80%, and in 4 (36.4%) of 11 patients with an extent of resection equal to or greater than 80% (multivariate analysis: p = 0.03).

Conclusions Insular gliomas grow in the space between the lateral surface of the IFOF and uncinate fasciculus and the insular surface, displacing and compressing the tracts medially. Moreover, these tracts may be completely infiltrated by the tumor, with a total disruption of the bundles. In the current study, the identification of the IFOF with DTI tractography was significantly associated with the extent of tumor resection. If the IFOF is not identified preoperatively, there is a high probability of achieving a resection greater than 80%.

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Transvenous Approach to Intracranial Arteriovenous Malformations

Transvenous Approach to Intracranial Arteriovenous Malformations

Neurosurgery 77:644–652, 2015

A compartmental conceptualization of intracranial arteriovenous malformations (AVMs) allows recognition of feeding arteries, an intervening plexiform nidus, and draining veins. AVM therapy involves eliminating the nidus, which is the source of hemorrhage, without compromising normal arterial and venous drainage of the brain. Traditional methods of AVM therapy through microsurgery and endovascular embolization involve arterial devascularization, with preservation of AVM venous drainage, until the nidus is excluded.

The transvenous approach in treating vascular malformations was popularized by successful treatment models for dural arteriovenous fistulas. More recently, high-flow intracranial AVMs are being managed with transvenous endovascular approaches, although this novel technique has its challenges and perils.

We review the current literature on transvenous AVM therapy and highlight its role for AVM therapy in the present day.

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What You See Is What You Get: Lead Location Within Deep Brain Structures Is Accurately Depicted by Stereotactic Magnetic Resonance Imaging

What You See Is What You Get- Lead Location Within Deep Brain Structures Is Accurately Depicted by Stereotactic Magnetic Resonance Imaging

Operative Neurosurgery 11:412–419, 2015

Magnetic resonance imaging (MRI)-verified deep brain stimulation relies on the correct interpretation of stereotactic imaging documenting lead location in relation to visible anatomic target. However, it has been suggested that local signal distortion from the lead itself renders its depiction on MRI unreliable.

OBJECTIVE: To compare lead location on stereotactic MRI with subsequent location of its brain track after removal.

METHODS: Patients underwent deep brain stimulation with the use of MRI-guided and MRI-verified Leksell frame approach. Infection or suboptimal efficacy required lead removal and subsequent reimplantation by using the same technique. Postimplantation stereotactic MR images were analyzed. Lateral (x) and anteroposterior (y) distances from midcommissural point to center of the lead hypointensity were recorded at the anterior commissure-posterior commissure plane (pallidal electrode) or z = 24 (subthalamic electrode). Stereotactic MRI before the second procedure, x and y distances from the center of the visible lead track hypointensity to midcommissural point were independently recorded. Vectorial distance from center of the lead hypointensity to the center of its track was calculated.

RESULTS: Sixteen electrode tracks were studied in 10 patients. Mean differences between lead artifact location and lead track location were: x coordinate 0.4 mm 6 0.2; y coordinate 0.6 mm 6 0.3. Mean vectorial distance was 0.7 mm 6 0.2.

CONCLUSION: Stereotactic distance between lead location and subsequent brain track location on MRI was small. The mean discrepancy was approximately half the deep brain stimulation lead width. This suggests that lead hypointensity seen on postimplantation MRI is indeed an accurate representation of its real location within deep brain structures.

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