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Staged Stereotactic Radiosurgery for Large Brain Metastases

Neurosurgery 83:114–121, 2018

Treatment options are limited for large, unresectable brain metastases.

OBJECTIVE: To report a single institution series of staged stereotactic radiosurgery (SRS) that allows for tumor response between treatments in order to optimize the therapeutic ratio.

METHODS: Patients were treated with staged SRS separated by 1 mo with a median dose at first SRS of 15 Gy (range 10-21 Gy) and a median dose at second SRS of 14 Gy (range 10-18 Gy). Overall survival was evaluated using the Kaplan-Meier method. Cumulative incidences were estimated for neurological death, radiation necrosis, local failure (marginal or central), and distant brain failure. Absolute cumulative dose–volume histogram was created for each treated lesion. Logistic regression and competing risks regression were performed for each discrete dose received by a certain volume.

RESULTS: Thirty-three patients with 39 lesions were treated with staged radiosurgery. Overall survival at 6 and 12mowas 65.0% and 60.0%, respectively. Cumulative incidence of local failure at 6 and 12 mo was 3.2% and 13.3%, respectively. Of the patients who received staged therapy, 4 of 33 experienced local failure. Radiation necrosis was seen in 4 of 39 lesions. Two of 33 patients experienced a Radiation Therapy Oncology Group toxicity grade >2 (2 patients had grade 4 toxicities). Dosimetric analysis revealed that dose (Gy) received by volume of brain (ie, VDose(Gy))was associated with radiation necrosis, including the range V44.5Gy to V87.8Gy.

CONCLUSION: Staged radiosurgery is a safe and effective option for large, unresectable brain metastases. Prospective studies are required to validate the findings in this study.

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Total en-bloc spondylectomy through a posterior approach: technique and surgical outcome in thoracic metastases

Acta Neurochirurgica (2018) 160:1373–1376

In 1981, Roy-Camille et al. have firstly reported the total en-bloc spondylectomy (TES) through a posterior approach for cases of malignant spine tumors in order to reduce the local recurrence and to increase the patient’s survival. By then, this surgery has been increasingly gaining recognition. However, it requires a high level of technical ability and knowledge of spinal anatomy, physiology, and biomechanics.

Method Herein, we report the patient’s selection and technique to execute the TES for cases of thoracic metastasis.

Conclusion This surgery is technically demanding so the patient’s selection requires a careful pre-operative evaluation. However, it can be suggested for patients affected by intracompartmental lesions with a good prognosis since the tumor’s progression is “limited” by local barriers as demonstrated by histological studies.

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Minimally Invasive Surgery is Superior to Conventional Craniotomy in Patients with Spontaneous Supratentorial Intracerebral Hemorrhage: A Systematic Review and Meta-Analysis

World Neurosurg. (2018) 115:266-273

Outcomes of minimally invasive surgery (MIS) versus conventional craniotomy (CC) for patients with spontaneous supratentorial intracerebral hemorrhage (SICH) have not been compared previously. We reviewed the current evidence regarding the safety and efficacy of MIS compared with CC in patients with SICH.

METHODS: We conducted a meta-analysis of studies comparing MIS and CC in patients with computed tomography confirmed SICH published between January 2000 and April 2018 in MEDLINE, Embase, and the Cochrane Controlled Trials Register based on PRISMA inclusion and exclusion criteria. Binary outcomes comparisons between MIS and CC were described using odds ratios (ORs).

RESULTS: Five randomized controlled trials (RCTs) and 9 prospective controlled studies (non-RCTs), involving a total of 2466 patients, met our inclusion criteria. There was a statistically significant difference in mortality rate between MIS and CC (OR, 0.76; 95% confidence interval [CI], 0.60e0.97). MIS was associated with a lower rate of rebleeding (OR, 0.42; 95% CI, 0.28e0.64) and a higher rate of good recovery compared with CC (OR, 2.27; 95% CI, 1.34e3.83).

CONCLUSIONS: Patients with SICH may benefit more from MIS than CC. Our study could help clinicians optimize treatment strategies in SICH

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Total Hospital Costs and Length of Stay of Endovascular Coiling Versus Neurosurgical Clipping for Unruptured Intracranial Aneurysms: Systematic Review and Meta-Analysis

World Neurosurg. (2018) 115:393-399

OBJECTIVE: Comparison of feasibility and safety between endovascular
coiling versus neurosurgical clipping for the management of unruptured intracranial aneurysms (UIAs) has been incrementally reported. However, economic comparison has been rarely reported. This meta-analysis aims at qualitatively and quantitatively analyzing the difference of hospital costs and length of stay between endovascular versus neurosurgical treatment in UIA.

METHODS: MEDLINE, the Cochrane database, EMBASE, and Web of Science
database were searched for cohort studies describing economic hospital cost or length of stay in patients with UIA. Two authors independently assessed study eligibility and rated quality using the Newcastle Ottawa Scale. Ravmen 5.2 was used to perform forest plot analysis.

RESULTS: Nine studies describing 24,856 UIAs treated with neurosurgical
clipping and 31,309 UIAs treated with endovascular coiling were included.
Meta-analysis revealed that the total hospital costs (THCs) were similar between coiling and clipping in UIA patients (standard mean difference
[SMD]: -0.33, 95% confidence interval: -0.68 to 0.02, f = 99%, P [ 0.07).
Subgroup analysis showed that THCs of coiling were significantly lower than
clipping in the United States but opposite in South Korea. One-year medical
costs of coiling were similar in both groups (SMD: -0.04, 95% CI: -0.08 to 0.00, f = 0%, P [ 0.07). In addition, the length of stay of coiling were significantly shorter than that of clipping (SMD: 0.69, 95% CI: 0.56e0.81, f = 95%, P < 0.001).

CONCLUSION: Generally, no significant difference in THCs and 1-year medical
costs between coiling versus clipping in UIAs was observed. However, the
length of stay of endovascular coiling was much shorter than neurosurgical
clipping and decreased over time.

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Pure arterial malformations

J Neurosurg 129:91–99, 2018

Over the last half century, there have been isolated case reports of purely arterial malformations. In this study, the authors report a consecutive series of patients with pure arterial malformations, emphasizing the clinical and radiological features of these lesions.

METHODS Pure arterial malformations were defined as dilated, overlapping, and tortuous arteries with a coil-like appearance and/or a mass of arterial loops without any associated venous component. Demographic characteristics of the patients, cardiovascular risk factors, presentation, radiological characteristics, and follow-up data were collected. Primary outcomes were new neurological symptoms including disability, stroke, and hemorrhage.

RESULTS Twelve patients meeting the criteria were identified. Ten patients were female (83.3%) and 2 were male (16.6%). Their mean age at diagnosis was 26.2 ± 11.6 years. The most common imaging indication was headache (7 patients [58.3%]). In 3 cases the pure arterial malformation involved the anterior cerebral arteries (25.0%); in 4 cases the posterior communicating artery/posterior cerebral artery (33.3%); in 2 cases the middle cerebral artery (16.6%); and in 1 case each, the superior cerebellar artery, basilar artery/anterior inferior cerebellar artery, and posterior inferior cerebellar artery. The mean maximum diameter of the malformations was 7.2 ± 5.0 mm (range 3–16 mm). Four lesions had focal aneurysms associated with the pure arterial malformation, and 5 were partially calcified. In no cases was there associated intracranial hemorrhage or infarction. One patient underwent treatment for the pure arterial malformation. All 12 patients had follow-up (mean 29 months, median 19 months), and there were no cases of disability, stroke, or hemorrhage.

CONCLUSIONS Pure arterial malformations are rare lesions that are often detected incidentally and probably have a benign natural history. These lesions can affect any of the intracranial arteries and are likely best managed conservatively.

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Electromagnetic neuronavigation for the percutaneous treatment of trigeminal neuralgia with balloon compression

Acta Neurochirurgica (2018) 160:1337–1341

Several techniques have been described for the percutaneous treatment of trigeminal neuralgia; however, each has significant drawbacks. We propose a new technique for percutaneous balloon compression of the trigeminal ganglion and distal trigeminal nerve using electromagnetic (EM) neuronavigation.

Methods The procedure was performed in 17 consecutive patients with trigeminal neuralgia. Patients were then followed up with telephone interview. We also performed a cadaveric validation study to further investigate the accuracy of the technique using dye.

Results Excellent clinical outcomes were achieved with a reduction in the median pain score from 10 out of 10 to 0 out of 10 following the procedure. The cadaveric study also demonstrated a high rate of foramen ovale cannulation.

Conclusion EM-based targeting of the foramen ovale and balloon inflation within Meckel’s cave is a quick, reproducible and straightforward technique for the percutaneous treatment of trigeminal neuralgia.

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Contralateral transmaxillary corridor: an augmented endoscopic approach to the petrous apex

J Neurosurg 129:211–219, 2018

The endoscopic endonasal approach (EEA) has been shown to be an effective means of accessing lesions of the petrous apex. Lesions that are lateral to the paraclival segment of the internal carotid artery (ICA) require lateralization of the paraclival segment of the ICA or a transpterygoid infrapetrous approach. In this study the authors studied the feasibility of adding a contralateral transmaxillary (CTM) corridor to provide greater access to the petrous apex with decreased need for manipulation of the ICA.

METHODS Using image guidance, EEA and CTM extension were performed bilaterally on 5 cadavers. The anterior wall of the sphenoid sinus and rostrum were removed. The angle of the surgical approach from the axis of the petrous segment of the ICA was measured. Five illustrative clinical cases are presented.

RESULTS The CTM corridor required a partial medial maxillectomy. When measured from the axis of the petrous ICA, the CTM corridor decreased the angle from 44.8° ± 2.78° to 20.1° ± 4.31°, a decrease of 24.7° ± 2.58°. Drilling through the CTM corridor allowed the drill to reach lateral aspects of the petrous apex that would have required lateralization of the ICA or would not have been accessible via EEA. The CTM corridor allowed us to achieve gross-total resection of the petrous apex region in 5 clinical cases with significant paraclival extension.

CONCLUSIONS The CTM corridor is a feasible extension to the standard EEA to the petrous apex that offers a more lateral trajectory with improved access. This approach may reduce the risk and morbidity associated with manipulation of the paraclival ICA.

 

 

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Cerebrovascular Imaging: Which Test is Best?

Neurosurgery 83:5–18, 2018

Optimal diagnosis and characterization of cerebrovascular disease requires selection of the appropriate imaging exam for each clinical situation.

In this review,we focus on intracranial arterial disease and discuss the techniques in current clinical use for imaging the blood vessel lumen and blood vessel wall, and for mapping cerebral hemodynamic impairment at the tissue level.

We then discuss specific strategies for imaging intracranial aneurysms, arteriovenous malformations, dural arterial venous fistulas, and arterial steno-occlusive disease.

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Surgical management of incidentally discovered diffusely infiltrating low-grade glioma

J Neurosurg 129:19–26, 2018

Occasionally, diffusely infiltrating low-grade gliomas (LGGs) are identified as incidental findings in patients who have no signs or symptoms that can be ascribed to the tumors. The diagnosis of incidental, asymptomatic LGGs has become more frequent due to the vast increase in access to medical imaging technology. While management of these lesions remains controversial, early surgery has been suggested to improve outcome. The authors set out to identify and review the characteristics and surgical outcomes of patients who underwent surgical intervention for incidental LGG.

METHODS All cases of LGG surgically treated between 2004 and 2016 at the authors’ institution were analyzed to identify those that were discovered incidentally. Patients with incidentally discovered LGGs were identified, and their cases were retrospectively reviewed. An “incidental” finding was defined as an abnormality on imaging that was obtained for a reason not attributable to the glioma, such as trauma, headache, screening, or research participation. Kaplan-Meier analysis was performed to determine actuarial rates of overall survival, progression-free survival, and malignant progression– free survival.

RESULTS In 34 (6.8%) of 501 adult patients who underwent surgery for LGG, the tumors were discovered incidentally. Headache (26%, n = 9) and screening (21%, n = 7) were the most common indications for brain imaging in this group. Four of these 34 patients had initial biopsy after the tumor was identified on imaging. In 5 cases, the patients opted for immediate resection; the remaining cases were managed with a “watch-and-wait” approach, with intervention undertaken only after radiological or clinical evidence of disease progression. The mean duration of follow-up for all 34 cases was 5 years. Twelve patients (35.3%) had disease progression, with an average time to progression of 43.8 months (range 3–105 months). There were 5 cases (14.7%) of malignant progression and 4 deaths (11.8%). Oligodendroglioma was diagnosed in 16 cases (47%) and astrocytoma in 15 (44%). Twenty-five patients (74%) had IDH1 mutation and demonstrated prolonged survival. Only 2 patients had mild surgery-related complications, and 16 patients (47%) developed epilepsy during the course of the disease.

CONCLUSIONS In this retrospective analysis of cases of incidentally discovered LGGs, the tumors were surgically removed with minimal surgical risk. In patients with incidental LGGs there is improved overall survival relative to median survival for patients with symptomatic LGGS, which is likely attributable to the underlying favorable biology of the disease indicated by the presence of IDH1 mutation in 74% of the cases.

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Accuracy in Identifying the Source of Subarachnoid Hemorrhage in the Setting of Multiple Intracranial Aneurysms

Neurosurgery 83:62–68, 2018

Subarachnoid hemorrhage cases with multiple cerebral aneurysms frequently demonstrate a hemorrhage pattern that does not definitively delineate the source aneurysm. In these cases, rupture site is ascertained from angiographic features of the aneurysm such as size, morphology, and location.

OBJECTIVE: To examine the frequency with which such features lead to misidentification of the ruptured aneurysm.

METHODS : Records of patients who underwent surgical clipping of a ruptured aneurysm at our institution between 2004 and 2014 and had multiple aneurysms were retrospectively reviewed. A blinded neuroendovascular surgeon provided the rupture source based on the initial head computed tomography scans and digital subtraction angiography images. Operative reports were then assessed to confirm or refute the imaging-based determination of the rupture source.

RESULTS: One hundred fifty-one patients had multiple aneurysms. Seventy-one patients had definitive hemorrhage patterns on initial computed tomography scans and 80 patients had nondefinitive hemorrhage patterns. Thirteen (16.2%) of the cases with nondefinitive hemorrhage patterns had discordance between the imaging-based determination of the rupture source and intraoperative findings of the true ruptured aneurysm, yielding an imperfect positive predictive value of 83.8%. Of all multiple aneurysm cases with subarachnoid hemorrhage treated by surgical or endovascular means at our institution, 4.3% (13 of 303) were misidentified.

CONCLUSION: Morphological features cannot reliably be used to determine rupture site in cases with nondefinitive subarachnoid hemorrhage patterns. Microsurgical clipping, confirming obliteration of the ruptured lesion, may be preferentially indicated in these patients unless, alternatively, all lesions can be contemporaneously and safely treatedwith endovascular embolization.

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Validation of the unruptured intracranial aneurysm treatment score.

J Neurosurg 129:100–106, 2018

The purpose of this study was to compare the unruptured intracranial aneurysm treatment score (UIATS) recommendations with the real-world experience in a quaternary academic medical center with a high volume of patients with unruptured intracranial aneurysms (UIAs).

METHODS All patients with UIAs evaluated during a 3-year period were included. All factors included in the UIATS were abstracted, and patients were scored using the UIATS. Patients were categorized in a contingency table assessing UIATS recommendation versus real-world treatment decision. The authors calculated the percentage of misclassification, sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve.

RESULTS A total of 221 consecutive patients with UIAs met the inclusion criteria: 69 (31%) patients underwent treatment and 152 (69%) did not. Fifty-nine (27%) patients had a UIATS between -2 and 2, which does not offer a treatment recommendation, leaving 162 (73%) patients with a UIATS treatment recommendation. The UIATS was significantly associated with treatment (p < 0.001); however, the sensitivity, specificity, and percentage of misclassification were 49%, 80%, and 28%, respectively. Notably, 51% of patients for whom treatment would be recommended by the UIATS did not undergo treatment in the real-world cohort and 20% of patients for whom conservative management would be recommended by UIATS had intervention. The area under the ROC curve was 0.646.

CONCLUSIONS Compared with the authors’ experience, the UIATS recommended overtreatment of UIAs. Although the UIATS could be used as a screening tool, individualized treatment recommendations based on consultation with a cerebrovascular specialist are necessary. Further validation with longitudinal data on rupture rates of UIAs is needed before widespread use.

 

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The pathophysiology of chronic noncommunicating hydrocephalus: lessons from continuous intracranial pressure monitoring and ventricular infusion testing

J Neurosurg 129:220–233, 2018

The pathophysiology of chronic noncommunicating hydrocephalus (ncHC) is poorly understood. This present study explored whether lessons about the pathophysiology of this clinical entity might be retrieved from results of overnight monitoring of pulsatile and static intracranial pressure (ICP) and ventricular infusion testing.

METHODS The study cohort included adult patients (> 20 years of age) with chronic ncHC due to aqueductal stenosis in whom symptoms had lasted a minimum of 6 months. A reference cohort consisted of age- and sex-matched patients managed for communicating HC (cHC). Information about symptoms and clinical improvement following surgery was retrieved from a quality register, and results of overnight ICP recordings and ventricular infusion testing were retrieved from the hospital ICP database.

RESULTS The cohort with ncHC consisted of 61 patients of whom 6 (10%) were managed conservatively, 34 (56%) by endoscopic third ventriculostomy (ETV), and 21 (34%) using ETV and subsequent shunt surgery. In patients responding to surgery, pulsatile ICP (mean ICP wave amplitude) was significantly increased to a similar magnitude in patients with ncHC and the reference cohort (cHC). Furthermore, intracranial compliance (ICC) was reduced in clinical responders. The results of ventricular infusion testing provided evidence that patients responding to ETV have impaired ventricular CSF absorption, while those requiring shunt placement after ETV present with impaired CSF absorption both in the intraventricular and extraventricular compartments.

CONCLUSIONS The study may provide some lessons about the pathophysiology of chronic ncHC. First, increased pulsatile ICP and impaired ICC characterize patients with chronic ncHC who respond clinically to CSF diversion surgery, even though static ICP is not increased. Second, in patients responding clinically to ETV, impaired ventricular CSF absorption may be a key factor. Patients requiring shunt placement for clinical response appear to have both intraventricular and extraventricular CSF absorption failure. A subgroup of patients with ncHC due to aqueductal stenosis has normal ventricular CSF absorption and normal ICC and may not be in need of surgical CSF diversion.

 

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Contralateral posterior interhemispheric approach to deep medial parietooccipital vascular malformations

J Neurosurg 129:198–204, 2018

Deep medial parietooccipital arteriovenous malformations (AVMs) and cerebral cavernous malformations (CCMs) are traditionally resected through an ipsilateral posterior interhemispheric approach (IPIA), which creates a deep, perpendicular perspective with limited access to the lateral margins of the lesion. The contralateral posterior interhemispheric approach (CPIA) flips the positioning, with the midline positioned horizontally for retraction due to gravity, but with the AVM on the upper side and the approach from the contralateral, lower side. The aim of this paper was to analyze whether the perpendicular angle of attack that is used in IPIA would convert to a parallel angle of attack with the CPIA, with less retraction, improved working angles, and no significant increase in risk.

METHODS A retrospective review of pre- and postoperative clinical and radiographic data was performed in 8 patients who underwent a CPIA.

RESULTS Three AVMs and 5 CCMs were resected using the CPIA, with an average nidus size of 2.3 cm and CCM diameter of 1.7 cm. All lesions were resected completely, as confirmed on postoperative catheter angiography or MRI. All patients had good neurological outcomes, with either stable or improved modified Rankin Scale scores at last follow-up.

CONCLUSIONS The CPIA is a safe alternative approach to the IPIA for deep medial parietooccipital vascular malformations that extend 2 cm or more off the midline. Contralaterality and retraction due to gravity optimize the interhemispheric corridor, the surgical trajectory to the lesion, and the visualization of the lateral margin, without resection or retraction of adjacent normal cortex. Although the falx is a physical barrier to accessing the lesion, it stabilizes the ipsilateral hemisphere while gravity delivers the dissected lesion through the transfalcine window. Patient positioning, CSF drainage, venous preservation, and meticulous dissection of the deep margins are critical to the safety of this approach.

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Frontal Lobe Epilepsy Surgery in Childhood and Adolescence: Predictors of Long-Term Seizure Freedom, Overall Cognitive and Adaptive Functioning

Neurosurgery 83:93–103, 2018

Although frontal lobe resections account for one-third of intralobar resections in pediatric epilepsy surgery, there is a dearth of information regarding long-term seizure freedom, overall cognitive and adaptive functioning.

OBJECTIVE: To identify outcome predictors and define the appropriate timing for surgery.

METHODS: We retrospectively analyzed the data of 75 consecutive patients aged 10.0 ± 4.9 yr at surgery that had an 8.1 yr mean follow-up.

RESULTS: Etiology comprised focal cortical dysplasia (FCD) in 71% and benign tumors in 16% cases. All patients but one had a magnetic resonance imaging-visible lesion. At last follow-up, 63% patients remained seizure-free and 37% had discontinued antiepileptic drugs. Presurgical predictors of seizure freedom were a shorter epilepsy duration, strictly regional epileptic discharges in electroencephalography (EEG), and an epileptogenic zone and/or lesion distant fromeloquent cortex. Postsurgical predictorswere the completeness of resection and the lack of early postoperative seizures or epileptic discharges in EEG. Higher presurgical overall cognitive and adaptive functioning was related to later epilepsy onset and to a sublobar epileptogenic zone and/or lesion. Following surgery, scores remained stable in themajority of patients. Postsurgical gains were determined by higher presurgical performance and tumors vs FCD.

CONCLUSION: Our findings highlight the favorable long-term outcomes following frontal lobe epilepsy surgery in childhood and adolescence and underline the importance of early surgical intervention in selected candidates. Early postsurgical relapses and epileptic discharges in EEG constitute key markers of treatment failure and should prompt timely reevaluation. Postsurgical overall cognitive and adaptive functioning is stable in most patients, whereas those with benign tumors have higher chances of improvement.

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Thalamic Glioblastoma: Clinical Presentation, Management Strategies, and Outcomes

Neurosurgery 83:76–85, 2018

Thalamic glioblastomas (GBMs) represent a significant neurosurgical challenge. In view of the low incidence of these tumors, outcome data and management strategies are not well defined.

OBJECTIVE: To identify the natural history and factors associated with survival in patients with thalamic glioblastoma.

METHODS: A retrospective review of all patients with thalamic glioblastoma over a 10-yr period was performed. Presenting clinical, radiological, and outcome data were collected. Chi-squared and Fisher’s exact tests were used to compare clinical characteristics across tumor groups. Cox proportional hazard models were utilized to investigate variables of interest with regard to overall survival.

RESULTS: Fifty-seven patients met inclusion criteria, with a median age of 53 and median Karnofsky Performance Scale (KPS) score of 80. The most common presenting symptoms were weakness, confusion, and headache. Hydrocephalus was present in 47% of patients preoperatively. Stereotactic biopsy was performed in 47 cases, and 10 patients underwent craniotomy. The median overall survival was 12.2 mo. Higher KPS, younger age, and cerebrospinal fluid (CSF) diversionwere correlatedwith better overall survival univariately, respectively, while the presence of language deficits at initial presentation was associated with poorer survival. In multivariate analysis, the only significant predictor of survival was presenting KPS.

CONCLUSION: The overall survival of patients with thalamic glioblastoma is comparable to unresectable lobar supratentorial GBMs. Younger patients and those with good presenting functional status had improved survival. Midbrain involvement by the tumor is not a negative prognostic factor. Improved therapies are needed, and patients should be considered for early trial involvement and aggressive upfront therapy.

 

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Lumbar disk herniation during pregnancy: a review on general management and timing of surgery

Acta Neurochir (2018) 160:1361–1370

Objective Provide an overview of existing management strategies to suggest a guideline for surgical management of lumbar disk herniation in pregnant women based on time of presentation.

Methods We performed a narrative review on the topic using the PubMed database. A total of 63 relevant articles published after 1992 were identified, of which 17 fulfilled selection criteria.

Results A total of 22 published cases of spine surgery for disk herniation during pregnancy were found in 17 studies on the topic. Prone positioning was reported in the majority of cases during the first and early second trimester. C-sections were performed prior to spine surgery in the prone position for the majority of patients operated during the third trimester. The left lateral position with continued pregnancy was preferred during the latter half of the second trimester when delivery of the fetus cannot yet be performed but surgery is indicated.

Conclusion Spine surgery during pregnancy is a rare scenario but can be performed safely when needed if providers adhere to general guidelines. Surgical approaches and overall management are influenced by the stage of pregnancy.

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Visual field deficits after epilepsy surgery: a new quantitative scoring method

Acta Neurochirurgica (2018) 160:1325–1336

Anterior temporal lobectomy (ATL) as a treatment for drug-resistant temporal lobe epilepsy (TLE) frequently causes visual field deficits (VFDs). Reported VFD encompasses homonymous contralateral upper quadrantanopia. Its reported incidence ranges from 15 to 90%. To date, a quantitative method to evaluate postoperative VFD in static perimetry is not available. A method to quantify postoperative VFD, which allows for comparison between groups of patients, was developed.

Methods Fifty-five patients with drug-resistant TLE, who underwent ATL with pre- and postoperative perimetry, were included. Temporal lobe resection length was measured on postoperative MRI. Percentage VFD was calculated for the total visual field, contralateral upper quadrant, or other three quadrants combined.

Results Patients were divided into groups by resection size (< 45 and ≥ 45 mm) and side of surgery (right and left).We found significant higher VFD in the ≥ 45 vs. < 45 mm group (2.3 ± 4.4 vs. 0.7 ± 2.4%,p = 0.04) for right-sided ATL. Comparing VFD in both eyes, we found more VFD in the right vs. left eye following left-sided ATL (14.5 ± 9.8 vs. 12.9 ± 8.3%, p = 0.03). We also demonstrated significantly more VFD in the < 45mm group for left- vs. right-sided surgery (6.7 ± 6.7 vs. 13.1 ± 7.0%, p = 0.016). A significant quantitative correlation between VFD and resection size for right-sided ATL was shown (r = 0.52, p < 0.01).

Conclusions We developed a new quantitative scoring method for the assessment of postoperative visual field deficits after temporal lobe epilepsy surgery and assessed its feasibility for clinical use. A significant correlation between VFD and resection size for right-sided ATL was confirmed.

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Characteristics of Unruptured Compared to Ruptured Intracranial Aneurysms: A Multicenter Case–Control Study

Neurosurgery 83:43–52, 2018

Only a minority of intracranial aneurysms rupture to cause subarachnoid hemorrhage.

OBJECTIVE: To test the hypothesis that unruptured aneurysms have different characteristics and risk factor profiles compared to ruptured aneurysms.

METHODS: We recruited patients with unruptured aneurysms or aneurysmal subarachnoid hemorrhages at 22 UK hospitals between 2011 and 2014. Demographic, clinical, and imaging data were collected using standardized case report forms. We compared risk factors using multivariable logistic regression.

RESULTS: A total of 2334 patients (1729 with aneurysmal subarachnoid hemorrhage, 605 with unruptured aneurysms) were included (mean age 54.22 yr). In multivariable analyses, the following variables were independently associated with rupture status: black ethnicity (odds ratio [OR] 2.42; 95% confidence interval [CI] 1.29-4.56, compared to white) and aneurysm location (anterior cerebral artery/anterior communicating artery [OR 3.21; 95% CI 2.34-4.40], posterior communicating artery [OR 3.92; 95% CI 2.67-5.74], or posterior circulation [OR 3.12; 95% CI 2.08-4.70], compared to middle cerebral artery). The following variables were inversely associated with rupture status: antihypertensive medication (OR 0.65; 95% CI 0.49-0.84), hypercholesterolemia (0.64 OR; 95% CI 0.48-0.85), aspirin use (OR 0.28; 95% CI 0.20-0.40), internal carotid artery location (OR 0.53; 95% CI 0.38-0.75), and aneurysm size (per mm increase; OR 0.76; 95% CI 0.69-0.84).

CONCLUSION: We show substantial differences in patient and aneurysm characteristics between ruptured and unruptured aneurysms. These findings support the hypothesis that different pathological mechanisms are involved in the formation of ruptured aneurysms and incidentally detected unruptured aneurysms. The potential protective effect of aspirin might justify randomized prevention trials in patients with unruptured aneurysms.

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Red-light excitation of protoporphyrin IX fluorescence for subsurface tumor detection

J Neurosurg 128:1690–1697, 2018

The objective of this study was to detect 5-aminolevulinic acid (ALA)-induced tumor fluorescence from glioma below the surface of the surgical field by using red-light illumination.

METHODS To overcome the shallow tissue penetration of blue light, which maximally excites the ALA-induced fluorophore protoporphyrin IX (PpIX) but is also strongly absorbed by hemoglobin and oxyhemoglobin, a system was developed to illuminate the surgical field with red light (620–640 nm) matching a secondary, smaller absorption peak of PpIX and detecting the fluorescence emission through a 650-nm longpass filter. This wide-field spectroscopic imaging system was used in conjunction with conventional blue-light fluorescence for comparison in 29 patients undergoing craniotomy for resection of high-grade glioma, low-grade glioma, meningioma, or metastasis.

RESULTS Although, as expected, red-light excitation is less sensitive to PpIX in exposed tumor, it did reveal tumor at a depth up to 5 mm below the resection bed in 22 of 24 patients who also exhibited PpIX fluorescence under blue-light excitation during the course of surgery.

CONCLUSIONS Red-light excitation of tumor-associated PpIX fluorescence below the surface of the surgical field can be achieved intraoperatively and enables detection of subsurface tumor that is not visualized under conventional bluelight excitation. Clinical trial registration no.: NCT02191488 (clinicaltrials.gov)

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