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Visual outcomes for surgical treatment of large and giant carotid ophthalmic segment aneurysms

Vision after aneurysm clipping with suction decompression

J Neurosurg 118:937–946, 2013

The authors report their results in a series of large or giant carotid ophthalmic segment aneurysms clipped using retrograde suction decompression.

Methods. A retrospective review of clinical data and treatment summaries was performed for 18 patients with large or giant carotid artery ophthalmic segment aneurysms managed operatively via retrograde suction decompression. Visual outcomes, Glasgow Outcome Scale (GOS) scores, and operative complications were determined. Postoperative angiography was assessed.

Results. During a 17-year period, 18 patients underwent surgery performed using retrograde suction decompression. The mean aneurysm size was 26 mm. Three patients presented with subarachnoid hemorrhage. Fourteen of 18 patients presented with visual symptoms. Eleven (79%) of these 14 patients experienced visual improvement and the remaining 3 (21%) experienced worsened vision after surgery. Of 3 patients without visual symptoms and a complete visual examination before and after surgery, 1 had visual worsening postoperatively. One aneurysm required trapping and bypass, and all others could be clipped. Postoperative angiography demonstrated complete occlusion in 9 of 17 clipped aneurysms and neck remnants in the other 8 clipped aneurysms. One (5.5%) of 18 patients experienced a stroke. Eighteen patients had a GOS score of 5 (good outcome), and 1 patient had a GOS score of 4 (moderately disabled). There were no deaths. There was no morbidity related to the second incision or decompression procedure. Prolonged improvement did occur, and even in some cases of visual worsening in 1 eye, the overall vision did improve enough to allow driving.

Conclusions. Retrograde suction decompression greatly facilitates surgical clipping for large and giant aneurysms of the ophthalmic segment. Visual preservation and improvement occur in the majority of these cases and is an important outcome measure. Developing endovascular technology must show equivalence or superiority to surgery for this specific outcome.

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Risk Factors for Pediatric Arachnoid Cyst Rupture/Hemorrhage: A Case-Control Study

Risk_Factors_for_Pediatric_Arachnoid_Cyst

As the availability of imaging modalities has increased, the finding of arachnoid cysts has become common. Accurate patient counseling regarding physical activity or risk factors for cyst rupture or hemorrhage has been hampered by the lack of definitive association studies.

OBJECTIVE: This case-control study evaluated factors that are associated with arachnoid cyst rupture (intracystic hemorrhage, adjacent subdural hematoma, or adjacent subdural hygroma) in pediatric patients with previously asymptomatic arachnoid cysts.

METHODS: Patients with arachnoid cysts and intracystic hemorrhage, adjacent subdural hygroma, or adjacent subdural hematoma treated at a single institution from 2005 to 2010 were retrospectively identified. Two unruptured/nonhemorrhagic controls were matched to each case based on patient age, sex, anatomical cyst location, and side. Risk factors evaluated included arachnoid cyst size, recent history of head trauma, and altitude at residence.

RESULTS: The proportion of imaged arachnoid cysts that presented either originally or subsequently with a rupture or hemorrhage was 6.0%. Larger cyst size, as defined by maximal cyst diameter, was significantly associated with cyst rupture/hemorrhage (P < .001). When dichotomized with a 5-cm cutoff, 9/13 larger cysts ruptured and/or hemorrhaged, whereas only 5/29 smaller cysts ruptured/hemorrhaged (odds ratio = 16.5 (confidence interval [2.5, N]). A recent history of head trauma was also significantly associated with the outcome (P < .001; odds ratio = 25.1 (confidence interval [4.0, N]). Altitude was not associated with arachnoid cyst rupture or hemorrhage.

CONCLUSION: This case-control study suggests that larger arachnoid cyst size and recent head trauma are risk factors for symptomatic arachnoid cyst rupture/hemorrhage.

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Infection rates of external ventricular drains are reduced by the use of silver-impregnated catheters

silverline_evd_catheter_3001202_1_m

Acta Neurochir (2013) 155:875–881

External ventricular drainage (EVD) placement for temporary cerebrospinal fluid (CSF) diversion is a frequent therapeutic procedure. Several types of EVD catheters are currently available, some of which have an antibacterial effect. This study compares the rates of CSF infections in patients with different types of EVD catheters.

Methods This is a retrospective study of 403 patients with a total of 529 implanted EVDs. We analyze the occurrence of EVD-associated infections, microbiological diagnosis, type of EVD catheter (plain polyurethane vs. silver-impregnated), duration of CSF diversion, primary disease, and outcome.

Results There were a total of 29 patients with EVD infections in the whole study group (7.1 %). A pathogen was detected in all cases. Coagulase-negative staphylococci were detected most frequently (20 out of 29 cases, 70 %). The rate of infections by catheter type was 7.6 % (11 of 145) and 13.8 % (4 out of 29) for two different types of noncoated polyurethane catheters. Silver-impregnated polyurethane catheters became infected in 6.1 % (14 out of 228). The differences between non-coated and silver-coated catheters were statistically significant.

Conclusions This study provides comparative data on EVD infections with regard to the type of catheter. Silverimpregnated catheters showed significantly lower infection rates when compared to non-impregnated catheters. The results are critically discussed and compared with the published literature.

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Indocyanine green videoangiography ‘‘in negative’’: definition and usefulness in spinal dural arteriovenous fistulae

SDAVF

Eur Spine J (2013) 22 (Suppl 3):S471–S477

Indocyanine green videoangiography (IGV) has proven its effectiveness in the field of exovascular neurosurgery, both in the intracranial and spinal compartment, but is necessary to define a systematic process for the performance of the IGV to facilitate its interpretation during the procedure. We have defined and applied the concept of videoangiography ‘‘in negative’’ (INIGV) to spinal dural arteriovenous fistulae (dAVF) for the detection and treatment of arteriovenous shunts, so called because the first phase is performed with the vessel suggestive of being pathological occluded.

Methods A Pentero-operating microscope with nearinfrared IGV-integrated system (Carl Zeiss Co., Germany) was used. At our institution, 24 patients were treated for a spinal dAVF between 1995 and 2011, only in the last 4 cases, INIGV was performed.

Results We describe the IGV in negative procedure and show the most illustrative cases. In all cases, the fistula occlusion was confirmed by postoperative selective digital subtraction angiography (DSA). INIGV demonstrate its capacity in detecting vessels not actually arterialized that should be respected and avoid some of the main limitations of the conventional IGV. This is a technical description about an Indocyanine green (ICG) videoangiographic procedure modification that is superior to merely performing ICG before and after clipping of a dAVF.

Conclusion The INIGV results are rapid and easy to interpret procedure and provide great advantages to the dAVF treatment. Nevertheless, further studies are needed with a larger sample size to determine if INIGV may reduce the need to perform immediate postoperative DSA.

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C2 root nerve sheath tumors management

C2 tumor

Acta Neurochir (2013) 155:779–784

Upper cervical nerve sheath tumors (NST) arising mainly from C2 root and to lesser extent from C1 root are not uncommon, they constitute approximately 5-12% of spinal nerve sheath tumors and 18-30% of all cervical nerve sheath tumors, unique in presentation and their relationship to neighbouring structures owing to the discrete anatomy at the upper cervical-craniovertebral region, and have a tendency for growth reaching large-sized tumors before manifesting clinically due to the capacious spinal canal at this region; accordingly the surgical approaches to such tumors are modified.

The aim of this paper is to discuss the surgical strategies for upper cervical nerve sheath tumors.

Methods Eleven patients (8 male and 3 females), age range 28 – 63 years, with C2 root nerve sheath tumors were operated upon based on their anatomical relations to the spinal cord. The magnetic resonance imaging findings were utilized to determine the surgical approach. The tumors had extra and intradural components in 10 patients, while in one the tumor was purely intradural. The operative approaches included varied from extreme lateral transcondylar approach( n =1) to laminectomy, whether complete( n =3) or hemilaminectomy( n =7), with partial facetectomy( n =7), and with suboccipital craniectomy( n =2).

Results The clinical picture ranged from spasticity ( n =8, 72,72 %), tingling and numbness below neck ( n =6, 54,54 %), weakness ( n =6, 54,54 %), posterior column involvement ( n =4, 26,36 %), and neck pain ( n =4, 36,36 %). The duration of symptoms ranged from 1 to 54 months, total excision was performed in 7 patients; while in 3 patients an extraspinal component, and in 1 patient a small intradural component, were left in situ. Eight patients showed improvement of myelopathy; 2 patients maintained their grades. One poor-grade patient was deteriorated.

Conclusion The surgical approaches for the C2 root nerve sheath tumors should be tailored according to the relationship to the spinal cord, determined by magnetic resonance imaging.

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Minimally invasive treatment of intracerebral hemorrhage with magnetic resonance–guided focused ultrasound

Sonothrombolysis in ICH

J Neurosurg 118:1035–1045, 2013

Intracerebral hemorrhage (ICH) is a major cause of death and disability throughout the world. Surgical techniques are limited by their invasive nature and the associated disability caused during clot removal. Preliminary data have shown promise for the feasibility of transcranial MR-guided focused ultrasound (MRgFUS) sonothrombolysis in liquefying the clotted blood in ICH and thereby facilitating minimally invasive evacuation of the clot via a twist-drill craniostomy and aspiration tube.

Methods and Results. In an in vitro model, the following optimum transcranial sonothrombolysis parameters were determined: transducer center frequency 230 kHz, power 3950 W, pulse repetition rate 1 kHz, duty cycle 10%, and sonication duration 30 seconds. Safety studies were performed in swine (n = 20). In a swine model of ICH, MRgFUS sonothrombolysis of 4 ml ICH was performed. Magnetic resonance imaging and histological examination demonstrated complete lysis of the ICH without additional brain injury, blood-brain barrier breakdown, or thermal necrosis due to sonothrombolysis. A novel cadaveric model of ICH was developed with 40-ml clots implanted into fresh cadaveric brains (n = 10). Intracerebral hemorrhages were successfully liquefied (> 95%) with transcranial MRgFUS in a highly accurate fashion, permitting minimally invasive aspiration of the lysate under MRI guidance.

Conclusions. The feasibility of transcranial MRgFUS sonothrombolysis was demonstrated in in vitro and cadaveric models of ICH. Initial in vivo safety data in a swine model of ICH suggest the process to be safe. Minimally invasive treatment of ICH with MRgFUS warrants evaluation in the setting of a clinical trial.

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Microvascular Decompression for Classic Trigeminal Neuralgia

MVD vascular compression

Neurosurgery 72:749–754, 2013

Outcomes studies use patient-reported outcome (PRO) measurements to assess treatment effectiveness, but can lack direct clinical meaning. Minimum clinically important difference (MCID) calculation provides a point estimate of the critical threshold needed to achieve clinically relevant treatment effectiveness. MCID remains uninvestigated for microvascular decompression (MVD), a common surgical procedure for trigeminal neuralgia. OBJECTIVE: We aimed to determine MCID for the most commonly used PRO measures of pain after MVD: Visual Analog Scale (VAS) and Barrow Neurological Institute Pain Scale (BNI-PS).

METHODS: Sixty consecutive patients with classic trigeminal neuralgia who decided to undergo MVD by a single surgeon were prospectively assessed with VAS and BNI-PS preoperatively and 2 years postoperatively. Three anchors were used to assign each patient’s outcome. We then used 3 well-established, anchor-based methods to calculate MCID.

RESULTS: Patients experienced significant improvement in both VAS (9.9 vs 2.0, P < .001) and BNI-PS (5.0 vs 1.9, P < .001) after MVD. The area under the receiver-operating characteristic curve was greater for BNI-PS than for VAS for all 3 anchors, indicating that BNI-PS is probably better suited for calculating MCID. The 3 MCID calculation methods generated a range of MCID values for each of the PROs (VAS: 1.40-8.87, BNI-PS: 0.95-3.26).

CONCLUSION: MVD-specific MCID is highly variable based on calculation technique. Some of these calculations appear to either overestimate or underestimate the patients’ preoperative expectations. When the different MCID methods are averaged, the results are clinically appropriate and consistent with preoperative expectations. The average MCID for VAS is 6.25 and for BNI-PS is 2.44.

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Characteristics and long-term outcome of 251 patients with dural arteriovenous fistulas in a defined population

DAVF-headache

J Neurosurg 118:923–934, 2013

Management of dural arteriovenous fistulas (DAVFs) has changed during the last decades due to increased knowledge of their pathophysiology and natural history as well as advances in treatment modalities. The authors describe the characteristics and long-term outcome of a large consecutive series of patients with DAVFs.

Methods. Altogether 251 patients with 261 DAVFs were treated in 2 of the 5 neurosurgery departments at Helsinki and Kuopio University Hospitals between 1944 and 2006. Clinical data and radiological examinations were reviewed to assess patients’ overall long-term clinical outcome.

Results. The detection rate of DAVFs increased markedly in the 1970s and again in the 1990s when digital subtraction angiography was introduced. The incidence of DAVFs in a defined southern Finnish population was 0.51 per 100,000 individuals per year, which represents 32% of all the brain arteriovenous malformations. In the early part of the series, DAVFs were treated by proximal ligation of the feeding arteries. Later, most of the patients underwent preoperative embolization and subsequent craniotomy, and since 2000 stereotactic radiosurgery has been increasingly used in the treatment of DAVFs. Fifty-nine percent of the 261 fistulas were totally occluded. Treatment-related major complications were seen in 21 patients.

Conclusions. The advances in diagnostic methods (digital subtraction angiography, CT, and MRI) increased the detection rate of DAVFs, and as treatment modalities developed, the results of treatment and outcome of patients markedly improved with the introduction of endovascular techniques and stereotactic radiosurgery. Microsurgery is of limited use in DAVFs resistant to other treatment modalities.

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The role of the cerebellopontine angle cistern area and trigeminal nerve length in the pathogenesis of trigeminal neuralgia

Role of CPA cistern and TN

Acta Neurochir (2013) 155:863–868

The aim of this prospective study was to evaluate whether the cerebellopontine angle (CPA) cistern area and trigeminal nerve cisternal length play a role in the pathogenesis of trigeminal neuralgia (TN).

Methods High-resolution 1.5 T magnetic resonance imaging of the posterior fossa was performed in 26 patients with TN and 18 age-matched healthy controls. Axial T2- weighted, three-dimensional constructive interference in steady-state (3D-CISS) was used to measure bilaterally the cross-sectional area of the CPA cistern and trigeminal nerve cisternal length.

Results In patients, the cross-sectional area of the CPA cistern and trigeminal nerve cisternal length was smaller on the affected side (p=0.04). Healthy controls tended to have larger cisternal areas and longer trigeminal nerve lengths than patients (p=0.059, p=0.071, respectively). Larger CPA cisternal areas tended to be seen in older patients. There was a strong correlation between the crosssectional area of the CPA cistern and the length of the trigeminal nerve (p=0.000).

Conclusions Smaller CPA cisterns and short cisternal trigeminal nerves impact the pathogenesis of essential TN by facilitating the neurovascular conflict, especially in younger patients. Trigeminal nerve cisternal measurement provides an easy and direct estimation of the CPA area. This information can be used for surgical planning and potentially for outcome prediction.

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Role of Endoscopic Third Ventriculostomy and Ventriculoperitoneal Shunt in Idiopathic Normal Pressure Hydrocephalus: Preliminary Results of a Randomized Clinical Trial

Role_of_Endoscopic_Third_Ventriculostomy_and

Neurosurgery 72:845–854, 2013

Currently, the most common treatment for idiopathic normal pressure hydrocephalus (INPH) is a ventriculoperitoneal shunt (VPS), generally with programmable valve implantation. Endoscopic third ventriculostomy (ETV) is another treatment option, and it does not require prosthesis implantation.

OBJECTIVE: To compare the functional neurological outcome in patients after 12 months of treatment with INPH by using 2 different techniques: ETV or VPS.

METHODS: Randomized, parallel, open-label trial involving the study of 42 patients with INPH and a positive response to the tap test, from January 2009 to January 2012. ETV was performed with a rigid endoscope with a 30 lens (Minop, Aesculap), and VPS was performed with a fixed-pressure valve (PS Medical, Medtronic). The outcome was assessed 12 months after surgery. The neurological function outcomes were based on the results of 6 clinical scales: mini-mental, Berg balance, dynamic gait index, functional independence measure, timed up and go, and normal pressure hydrocephalus.

RESULTS: There was a statistically significant difference between the 2 groups after 12 months of follow-ups, and the VPS group showed better improvement results (ETV = 50%, VPS = 76.9%).

CONCLUSION: Compared with ETV, VPS is a superior method because it had better functional neurological outcomes 12 months after surgery.

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Is endoscopic third ventriculostomy superior to shunts in patients with non-communicating hydrocephalus?

ETV

Acta Neurochir (2013) 155:883–889

Endoscopic third ventriculostomy (ETV) and shunts are both utilized in the treatment of noncommunicating hydrocephalus. The objective of this study was to review the evidence comparing the effectiveness of these two techniques.

Methods The Cochrane Central Register of Controlled Trials (CENTRAL) and Medline databases were searched between 1990 and August 2012. We included all studies comparing the failure rate of patients with noncommunicating hydrocephalus treated with ETVand shunts. Two authors (HJM and FTR) appraised quality and extracted data independently.

Results Of 313 articles identified, 12 were selected for further review. Of these, 6 were included for qualitative analysis, and 5 for quantitative analysis (n=504). ETV was associated with a non-statistically significant reduction in failure using the random-effects model (OR 0.58, 95 % CI 0.29-1.13).

Conclusions Both ETV and shunts are associated with a relatively high failure rate. At present there is insufficient proof to unequivocally recommend one mode of treatment above the other. However, there is some evidence that ETV may confer long-term survival advantage over shunts in the treatment of non-communicating hydrocephalus, particularly in patients with certain aetiologies such as aqueductal stenosis. Prospective randomized controlled trials are currently underway and may provide more robust evidence to answer this important question and better guide future management.

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The Silent Loss of Neuronavigation Accuracy

The_Silent_Loss_of_Neuronavigation_Accuracy___A-1

Neurosurgery 72:796–807, 2013

Neuronavigation has become an intrinsic part of preoperative surgical planning and surgical procedures. However, many surgeons have the impression that accuracy decreases during surgery.

OBJECTIVE: To quantify the decrease of neuronavigation accuracy and identify possible origins, we performed a retrospective quality-control study.

METHODS: Between April and July 2011, a neuronavigation system was used in conjunction with a specially prepared head holder in 55 consecutive patients. Two different neuronavigation systems were investigated separately. Coregistration was performed with laser-surface matching, paired-point matching using skin fiducials, anatomic landmarks, or bone screws. The initial target registration error (TRE1) was measured using the nasion as the anatomic landmark. Then, after draping and during surgery, the accuracy was checked at predefined procedural landmark steps (Mayfield measurement point and bone measurement point), and deviations were recorded.

RESULTS: After initial coregistration, the mean (SD) TRE1 was 2.9 (3.3) mm. The TRE1 was significantly dependent on patient positioning, lesion localization, type of neuroimaging, and coregistration method. The following procedures decreased neuronavigation accuracy: attachment of surgical drapes (DTRE2 = 2.7 [1.7] mm), skin retractor attachment (DTRE3 = 1.2 [1.0] mm), craniotomy (DTRE3 = 1.0 [1.4] mm), and Halo ring installation (DTRE3 = 0.5 [0.5] mm). Surgery duration was a significant factor also; the overall DTRE was 1.3 [1.5] mm after 30 minutes and increased to 4.4 [1.8] mm after 5.5 hours of surgery.

CONCLUSION: After registration, there is an ongoing loss of neuronavigation accuracy. The major factors were draping, attachment of skin retractors, and duration of surgery. Surgeons should be aware of this silent loss of accuracy when using neuronavigation.

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Incidence of Neurosurgical Wrong-Site Surgery Before and After Implementation of the Universal Protocol

Wrong-site spinal surgery

Neurosurgery 72:590–595, 2013

Although exceedingly rare, wrong-site surgery (WSS) remains a persistent problem in the United States. The incidence is thought to be 2 to 3 per 10 000 craniotomies and about 6 to 14 per 10 000 spine surgeries. In July 2004, the Joint Commission mandated the Universal Protocol (UP) for all accredited hospitals.

OBJECTIVE: To assess the effect of UP implementation on the incidence of neurosurgical WSS at the University of Illinois College of Medicine at Peoria/Illinois Neurological Institute.

METHODS: The Morbidity and Mortality Database in the Department of Neurosurgery was reviewed to identify all recorded cases of WSS since 1999. This was compared with the total operative load (excluding endovascular procedures) of all attending neurosurgeons to determine the incidence of overall WSS. A comparison was then made between the incidences before and after UP implementation.

RESULTS: Fifteen WSS events were found with an overall incidence of 0.07% and Poisson 95% confidence interval of 8.4 to 25. All but one of these were wrong-level spine surgeries (14/15). There was only 1 recorded case of wrong-side surgery and this occurred after implementation of the UP. A statistically greater number of WSS events occurred before (n = 12) in comparison with after (n = 3) UP implementation (P < .001).

CONCLUSION: A statistically significant reduction in overall WSS was seen after implementation of the UP. This reduction can be attributed to less frequent wronglevel spine surgery. There was no case of wrong procedure or patient surgery and the 1 case of wrong-side surgery occurred after UP implementation.

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Postoperative ischemic changes following resection of newly diagnosed and recurrent gliomas and their clinical relevance

Postoperative ischemic changes following resection of newly diagnosed and recurrent gliomas and their clinical relevance

J Neurosurg 118:801–808, 2013

The aim of surgical treatment of glioma is the complete resection of tumor tissue with preservation of neurological function. Inclusion of diffusion-weighted imaging (DWI) in the postoperative MRI protocol could improve the delineation of ischemia-associated postoperative neurological deficits. The present study aims to assess the incidence of infarctions following resection of newly diagnosed gliomas in comparison with recurrent gliomas and the influence on neurological function.

Methods. Patients who underwent glioma resection for newly diagnosed or recurrent gliomas had early postoperative MRI, including DWI and apparent diffusion coefficient (ADC) maps. Postoperative areas of restricted diffusion were classified as arterial territorial infarctions, terminal branch infarctions, or venous infarctions. Tumor entity, location, and neurological function were recorded.

Results. New postoperative ischemic lesions were identified in 26 (31%) of 84 patients with newly diagnosed gliomas and 20 (80%) of 25 patients with recurrent gliomas (p < 0.01). New permanent and transient neurological deficits were more frequent in patients with recurrent gliomas than in patients with newly diagnosed tumors. Patients with neurological deficits had a significantly higher rate of ischemic lesions.

Conclusions. Postoperative infarctions occur frequently in patients with newly diagnosed and recurrent gliomas and do have an impact on postoperative neurological function. In this patient cohort there was a higher risk for ischemic lesions and for deterioration of neurological function after resection of recurrent tumors. Radiogenic and postoperative tissue changes could contribute to the higher risk of an ischemic infarction in patients with recurrent tumors.

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Reoperation Rate After Surgery for Lumbar Herniated Intervertebral Disc Disease

herniated_disc

Spine 2013 ; 38 : 581 – 590

Retrospective cohort study using national health insurance data.

Objective. To provide a longitudinal reoperation rate after surgery for lumbar herniated intervertebral disc (HIVD) disease, and to compare the reoperation rates of surgical methods.

Summary of Background Data. Herniated intervertebral disc disease is the most common cause of lumbar spinal surgery. Despite improved surgical techniques and instrumentation, reoperation cannot be avoided. The reoperation rates were in the range of 6% to 24% in previous studies. A population-based study is less subject to bias; hence, a nationwide longitudinal analysis was warranted.

Methods. A national health insurance database was used to identify a cohort of patients who underwent fi rst surgery for herniated intervertebral disc disease in 2003 and 18,590 patients were selected. Individual patients were followed for at least 5 years through their encrypted unique resident registration number. The primary endpoint was any type of second lumbar surgery. After adjusting for confounding factors, 5 surgical methods (fusion, laminectomy, open discectomy, endoscopic discectomy, and nucleolysis [including mechanical nucleus decompression]) were compared. Open discectomy was used as the reference method.

Results. Open discectomy was the most common procedure (68.9%) followed by endoscopic discectomy (16.1%), laminectomy (7.9%), fusion (3.9%), and nucleolysis (3.2%). The cumulative reoperation rate was 5.4% at 3 months, 7.4% at 1 year, 9% at 2 years, 10.5% at 3 years, 12.1% at 4 years, and 13.4% at 5 years. The reoperation rates were 18.6%, 14.7%, 13.8%, 12.4%, and 11.8% after laminectomy, nucleolysis, open discectomy, endoscopic discectomy, and fusion, respectively. Compared with open discectomy, the reoperation rate was higher after laminectomy at 3 months, whereas the other surgical methods had similar rates.

Conclusion. The cumulative reoperation rate after 5 years was 13.4% and half of the reoperations occurred during the fi rst postoperative year. With the exception of laminectomy, the reoperation rates of the other procedures were not different from that of open discectomy.

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Transventricular Endoscopic Fenestration of Intrasellar Arachnoid Cyst

Transventricular

Neurosurgery 72:520–528, 2013

To manage arachnoid cysts, incorporation with the normal circulation is the single most important determinant of success. Although the postoperative cerebrospinal fluid leakage rate is 3.9% for all cases of transsphenoidal surgery, it is 21.4% for intrasellar arachnoid cysts.

OBJECTIVE: To present a safe, relatively easy, and effective treatment option for very rare intrasellar arachnoid cysts.

METHODS: We performed a prospective study of intrasellar cystic lesions without a solid portion. Endoscopic exploration and fenestration were performed for all lesions under neuronavigational guidance. We analyzed presenting symptoms, endocrinological status, and magnetic resonance images.

RESULTS: There were 2 male and 4 female patients with a mean age of 45 years (range, 27-67 years). All patients presented with the visual disturbance of bitemporal hemianopsia. Four patients had endocrinological symptoms including galactorrhea, dysmenorrhea, and diabetes insipidus. Endoscopic fenestration of the cyst was successfully performed in all patients. All patients were confirmed to have a pure cystic lesion, namely an arachnoid cyst. The follow-up period was 10 months on average (range, 6-12 months). Visual disturbance improved in 5 patients. Endocrinological problems persisted in all patients for 3 months and then normalized, with the exception of the patient with diabetes insipidus. There was no evidence of recurrence in any of the 6 patients in the 12-month postoperative imaging studies (median follow-up of 10 months). Two patients showed syndrome of inappropriate antidiuretic hormone at 2 and 4 weeks after the operation, but antidiuretic hormones recovered to normal levels after this time point.

CONCLUSION: Endoscopic fenestration of an intrasellar arachnoid cyst is a safe and simple procedure without serious complications.

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Microvascular decompression for hemifacial spasm: long-term outcome and prognostic factors, with emphasis on delayed cure

PE-Hemifacial

Neurosurg Rev (2013) 36:297–302

The postoperative course of microvascular decompression (MVD) for hemifacial spasm (HFS) is variable, and the optimal time for assessing the results is unclear.

From April 1997 to October 2007, MVD for HFS was performed in 801 patients. Patients were divided into two groups (cured or failed) according to subjective patient assessments over a 3-year period. We analyzed patient characteristics and surgical findings to determine prognostic factors. Medical records were analyzed retrospectively over the 3-year follow-up period.

Of the 801 patients who underwent surgery, 743 (92.8 %) appeared to be cured, 70 (8.7 %) had residual or recurrent spasms more than 1 year after surgery, 11 (1.3 %) had gradual improvement over 3 years, and 1 (0.1 %) had delayed improvement more than 3 years after surgery. Fifty-eight patients (7.2 %) had residual or recurrent spasms more than 3 years after surgery, of which 19 (2.4 %) had recurrence after initial relief. The mean time to spasm recurrence was 18.9 months. Intraoperative resolution of the lateral spread response (LSR) after decompression (p=0.048) and severe indentation (p=0.038) were significant predictors of good long-term outcome after MVD for HFS.

In our series, 70 patients (8.7 %) had residual or recurrent spasms more than 1 year after surgery, of which 12 (17.1 %) improved gradually after 1 year. If the surgeon can confirm intraoperative resolution of the LSR and severe indentation, reoperation can be delayed until 3 years after MVD.

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Multiple resections for patients with glioblastoma: prolonging survival

Prolonged survival GBM

J Neurosurg 118:812–820, 2013

Glioblastoma is the most common and aggressive type of primary brain tumor in adults. These tumors recur regardless of intervention. This propensity to recur despite aggressive therapies has made many perceive that repeated resections have little utility. The goal of this study was to evaluate if patients who underwent repeat resections experienced improved survival as compared with patients with fewer numbers of resections, and whether the number of resections was an independent predictor of prolonged survival.

Methods. The records of adult patients who underwent surgery for an intracranial primary glioblastoma at an academic tertiary-care institution between 1997 and 2007 were retrospectively reviewed. Multivariate proportionalhazards regression analysis was used to identify an association between glioblastoma resection number and survival after controlling for factors known to be associated with survival, such as age, functional status, periventricular location, extent of resection, and adjuvant therapy. Survival as a function of time was plotted using the Kaplan-Meier method, and survival rates were compared using log-rank analysis.

Results. Five hundred seventy-eight patients with primary glioblastoma met the inclusion/exclusion criteria. At last follow-up, 354, 168, 41, and 15 patients underwent 1, 2, 3, or 4 resections, respectively. The median survival for patients who underwent 1, 2, 3, and 4 resections was 6.8, 15.5, 22.4, and 26.6 months (p < 0.05), respectively. In multivariate analysis, patients who underwent only 1 resection experienced shortened survival (relative risk [RR] 3.400, 95% CI 2.423–4.774; p < 0.0001) as compared with patients who underwent 2 (RR 0.688, 95% CI 0.525–0.898; p = 0.0006), 3 (RR 0.614, 95% CI 0.388–0.929; p = 0.02), or 4 (RR 0.600, 95% CI 0.238–0.853; p = 0.01) resections. These results were verified in a case-control evaluation, controlling for age, neurological function, periventricular tumor location, extent of resection, and adjuvant therapy. Patients who underwent 1, 2, or 3 resections had a median survival of 4.5, 16.2, and 24.4 months, respectively (p < 0.05). Additionally, the risk of infections or iatrogenic deficits did not increase with repeated resections in this patient population (p > 0.05).

Conclusions. Patients with glioblastoma will inevitably experience tumor recurrence. The present study shows that patients with recurrent glioblastoma can have improved survival with repeated resections. The findings of this study, however, may be limited by an intrinsic bias associated with patient selection. The authors attempted to minimize these biases by using strict inclusion criteria, multivariate analyses, and case-control evaluation.

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Radiation-Induced Complications in Endovascular Neurosurgery

Table Height

Neurosurgery 72:566–572, 2013

The incidence of radiation-induced complications is increasingly part of the informed consent process for patients undergoing neuroendovascular procedures. Data guiding these discussions in the era of modern radiation-minimizing equipment is lacking.

OBJECTIVE: To quantify the rates of skin and hair effects at a modern high-volume neurovascular center, and to assess the feasibility of accurately quantifying the risk of future central nervous system (CNS) tumor formation.

METHODS: We reviewed a prospectively collected database of endovascular procedures performed at our institution in 2008. The entrance skin dose and brain dose were calculated. Patients receiving skin doses .2 Gy were contacted to inquire about skin and hair changes. We reviewed several recent publications from leading radiation physics bodies to evaluate the feasibility of accurately predicting future cancer risk from neurointerventional procedures.

RESULTS: Seven hundred two procedures were included in the study. Of the patients receiving .2 Gy, 39.6% reported subacute skin or hair changes following their procedure, of which 30% were permanent. Increasing skin dose was significantly associated with permanent hair loss. We found substantial methodological difficulties in attempting to model the risk of future CNS tumor formation given the gaps in our current understanding of the brain’s susceptibility to low-dose ionizing radiation.

CONCLUSION: Radiation exposures exceeding 2 Gy are common in interventional neuroradiology despite modern radiation-minimizing technology. The incidence of side effects approaches 40%, although the majority is self-limiting. Gaps in current models of brain tumor formation after exposure to radiation preclude accurately quantifying the risk of future CNS tumor formation.

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Size Ratio Performance in Detecting Cerebral Aneurysm Rupture Status Is Insensitive to Small Vessel Removal

Siza Ratio as rupture discriminant

Neurosurgery 72:547–554, 2013 

The variable definition of size ratio (SR) for sidewall (SW) vs bifurcation (BIF) aneurysms raises confusion for lesions harboring small branches, such as carotid ophthalmic or posterior communicating locations. These aneurysms are considered SW by many clinicians, but SR methodology classifies them as BIF.

OBJECTIVE: To evaluate the effect of ignoring small vessels and SW vs stringent BIF labeling on SR ruptured aneurysm detection performance in borderline aneurysms with small branches, and to reconcile SR-based labeling with clinical SW/BIF classification.

METHODS: Catheter rotational angiographic datasets of 134 consecutive aneurysms (60 ruptured) were automatically measured in 3-dimensional. Stringent BIF labeling was applied to clinically labeled aneurysms, with 21 aneurysms switching label from SW to BIF. Parent vessel size was evaluated both taking into account, and ignoring, small vessels. SR was defined accordingly as the ratio between aneurysm and parent vessel sizes. Univariate and multivariate statistics identified significant features. The square of the correlation coefficient (R2) was reported for bivariate analysis of alternative SR calculations.

RESULTS: Regardless of SW/BIF labeling method, SR was equally significant in discriminating aneurysm ruptured status (P , .001). Bivariate analysis of alternative SR had a high correlation of R2 = 0.94 on the whole dataset, and R2 = 0.98 on the 21 borderline aneurysms.

CONCLUSION: Ignoring small branches from SR calculation maintains rupture status detection performance, while reducing postprocessing complexity and removing labeling ambiguity. Aneurysms adjacent to these vessels can be considered SW for morphometric analysis. It is reasonable to use the clinical SW/BIF labeling when using SR for rupture risk evaluation.

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