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Value of whole-body low-dose computed tomography in patients with ventriculoperitoneal shunts: a retrospective study

J Neurosurg 129:1598–1603, 2018

The gold standard for evaluation of ventriculoperitoneal (VP) shunt position, dislocation, or disconnection is conventional radiography. Yet, assessment with this modality can be challenging because of low image quality and can result in repetitive radiation exposure with high fluctuation in the radiation dose. Recently, CT-based radiation doses have been significantly reduced by using low-dose protocols. Thus, whole-body low-dose CT (LDCT) has become applicable for routine use in VP shunt evaluation. The authors here compared image quality and approximate radiation dose between radiography and LDCT in patients with implanted VP shunt systems.

METHODS Ventriculoperitoneal shunt systems have been investigated with LDCT scanning at the authors’ department since 2015. A consecutive series of 57 patients (70 investigations) treated between 2015 and 2016 was retrospectively assessed. A historical patient cohort that had been evaluated with radiography was compared with the LDCT patients in terms of radiation dose and image quality. Three independent observers evaluated projection of the valve pressure level and correct intraperitoneal position, as well as complete shunt projection, using a Likert-type scale of 1–5, where 1 indicated “not assessable” and 5 meant “assessable with high accuracy.” Descriptive statistics and the Mann-Whitney U-test were used for analysis.

RESULTS Twenty-seven radiographs (38.6%) and 43 LDCT scans (61.4%) were analyzed. The median dose-length product (DLP) of the LDCT scans was 100 mGy·cm (range 59.9–183 mGy·cm). The median total dose-area product (DAP) of the radiographic images was 3177 mGy·cm2 (range 641–13,833 mGy·cm2). The estimated effective dose (EED) was significantly lower with the LDCT scan (p < 0.001). The median EED was 4.93 and 1.90 mSv for radiographs and LDCT, respectively. Significantly better identification of the abdominal position of the distal shunt catheter was achieved with LDCT (p < 0.001). Simultaneously, significantly improved visualization of the entire shunt system was realized with this technique (p < 0.001). On the contrary, identification of the valve settings was significantly worse with LDCT (p < 0.001).

CONCLUSIONS Whole-body LDCT scanning allows good visualization of the distal catheter after VP shunt placement. Despite the fact that only a rough estimation of effective doses is possible in a direct comparison of LDCT and radiography, the data showed that shunt assessment via LDCT does not lead to greater radiation exposure. Thus, especially in difficult anatomical conditions, as in patients who have undergone multiple intraabdominal surgeries, have a high BMI, or are immobile, the use of LDCT shunt evaluation has high clinical value. Further data are needed to determine the value of LDCT for the evaluation of complications or radiation dose in pediatric patients.

 

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Total En Bloc Spondylectomy for Lumbar Spinal Tumors by Paraspinal Approach

World Neurosurg. (2018)120:28-35

OBJECTIVE: To report and describe a modified posterioronly
approach (paraspinal approach) for total en bloc
spondylectomy (TES) of lumbar spinal tumors.

METHODS: From February 2013 to June 2014, 5 patients
with lumbar spinal tumors who underwent TES through a
posterior-only paraspinal approach were studied retrospectively;
operative time, blood loss, complications,
neurologic outcomes, and degree of resection were
recorded to evaluate the efficacy of this surgical method.

RESULTS: Patients included 3 men and 2 women with a
mean age of 48.4 years (range, 46e52 years). Two lesions
were located in L2, 2 lesions were located in L3, and 1
lesion was located in L4. Three patients had solitary
metastatic tumors (lung cancer in 2 cases, breast cancer
in 1 case), and 2 patients had primary tumors (osteosarcoma
and plasma cell tumor). According to the surgical
classification of spinal tumors by Tomita et al., 4 cases
were type 4 and 1 case was type 1. Mean operative time
was 464 minutes (range, 420-510 minutes), and mean
blood loss was 1280 mL (range, 1000-1500 mL). One
patient had cerebrospinal fluid leakage, and 1 had transient
motor weakness because of nerve root traction.
Mean follow-up time was 20.6 months (range, 12e30
months), and all patients had improved or stable neurologic
function. No local recurrence was observed at last
follow-up.

CONCLUSIONS: The posterior-only paraspinal approach
is a valid alternative for TES of lumbar spinal tumors,
especially for overweight or muscular patients.

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Volumetric changes and clinical outcome for petroclival meningiomas after primary treatment with Gamma Knife radiosurgery

J Neurosurg 129:1623–1629, 2018

Petroclival meningiomas (PCMs) can cause devastating clinical symptoms due to mass effect on cranial nerves (CNs); thus, patients harboring these tumors need treatment. Many neurosurgeons advocate for microsurgery because removal of the tumor can provide relief or result in symptom disappearance. Gamma Knife radiosurgery (GKRS) is often an alternative for surgery because it can cause tumor shrinkage with improvement of symptoms. This study evaluates qualitative volumetric changes of PCM after primary GKRS and its impact on clinical symptoms.

METHODS The authors performed a retrospective study of patients with PCM who underwent primary GKRS between 2003 and 2015 at the Gamma Knife Center of the Elisabeth-Tweesteden Hospital in Tilburg, the Netherlands. This study yields 53 patients. In this study the authors concentrate on qualitative volumetric tumor changes, local tumor control rate, and the effect of the treatment on trigeminal neuralgia (TN).

RESULTS Local tumor control was 98% at 5 years and 93% at 7 years (Kaplan-Meier estimates). More than 90% of the tumors showed regression in volume during the first 5 years. The mean volumetric tumor decrease was 21.2%, 27.1%, and 31% at 1, 3, and 6 years of follow-up, respectively. Improvement in TN was achieved in 61%, 67%, and 70% of the cases at 1, 2, and 3 years of follow-up, respectively. This was associated with a mean volumetric tumor decrease of 25% at the 1-year follow-up to 32% at the 3-year follow-up.

CONCLUSIONS GKRS for PCMs yields a high tumor control rate with a low incidence of neurological deficits. Many patients with TN due to PCM experienced improvement in TN after radiosurgery. GKRS achieves significant volumetric tumor decrease in the first years of follow-up and thereafter.

 

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Microsurgical clipping of ophthalmic artery aneurysms

J Neurosurg 129:1511–1521, 2018

While most paraclinoid aneurysms can be clipped with excellent results, new postoperative visual deficits are a concern. New technology, including flow diverters, has increased the popularity of endovascular therapy. However, endovascular treatment of paraclinoid aneurysms is not without procedural risks, is associated with higher rates of incomplete aneurysm occlusion and recurrence, and may not address optic nerve compression symptoms that surgical debulking can. The increasing endovascular management of paraclinoid aneurysms should be justified by comparisons to surgical benchmarks. The authors, therefore, undertook this study to define patient, visual, and aneurysm outcomes in the most common type of paraclinoid aneurysm: ophthalmic artery (OphA) aneurysms.

METHODS Results from microsurgical clipping of 208 OphA aneurysms in 198 patients were retrospectively reviewed. Patient demographics, aneurysm morphology (size, calcification, etc.), clinical characteristics, and patient outcomes were recorded and analyzed.

RESULTS Despite 20% of these aneurysms being large or giant in size, complete aneurysm occlusion was accomplished in 91% of 208 cases, with OphA patency preserved in 99.5%. The aneurysm recurrence rate was 3.1% and the retreatment rate was 0%. Good outcomes (modified Rankin Scale score 0–2) were observed in 96.2% of patients overall and in all 156 patients with unruptured aneurysms. New visual field defects (hemianopsia or quadrantanopsia) were observed in 8 patients (3.8%), decreased visual acuity in 5 (2.4%), and monocular blindness in 9 (4.3%). Vision improved in 9 (52.9%) of the 17 patients with preoperative visual deficits.

CONCLUSIONS The most important risk associated with clipping OphA aneurysms is a new visual deficit. Meticulous microsurgical technique is necessary during anterior clinoidectomy, aneurysm dissection, and clip application to optimize visual outcomes, and aggressive medical management postoperatively might potentially decrease the incidence of delayed visual deficits. As the results of endovascular therapy and specifically flow diverters become known, they warrant comparison with these surgical benchmarks to determine best practices.

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Radiosurgery and fractionated radiotherapy for cavernous sinus meningioma: a systematic review and meta-analysis

Acta Neurochirurgica (2018) 160:2367–2378

Radiosurgery (RS) and fractionated radiotherapy (FRT) are part of the therapeutic armamentarium for the management of cavernous sinus meningiomas. We propose a systematic review of the local tumor control and clinical outcomes after monofractionated radiosurgical treatment, including gamma knife radiosurgery (GKRS) and linear accelerator (Linac RS), or fractionated radiotherapy.

Materials and Methods: The current review and meta-analysis adhered to the PRISMA guidelines. We performed a search in PubMed, Embase, and Medline based on the following mesh terms, used alone or in diverse combinations, in both title and abstract: “cavernous sinus”, “meningioma”, “radiosurgery”, “gamma knife”,”linac”, “cyberknife” and “radiotherapy”. We screened 425 studies. We selected 36 studies, matching all selection criteria: 24 for GK, 5 for Linac, and 7 for FRT.

Results: Were included 2817 patients (GKRS, n = 2047, LinacRS, n = 350, FRT, n = 420). Half of patients benefited from upfront RS or FRT; the other half benefited from adjuvant RS or FRT (combined approach or tumor recurrence). The mean gross target volume (GTV) was smaller for RS as compared to FRT (p = 0.07). The median marginal doses were 13.9 Gy (range, 11 to 28) for GKRS and 14 Gy (range, 12.8 to 17.7) for LinacRS. For FRT, patients received a mean dose of 51.2 Gy (25.5 fractions, 1.85 Gy each). The mean overall follow-up values were 48 months (range, 15 to 89) for GKRS, 69 months (range, 46 to 87) for Linac, and 59.5 months (range, 33 to 83) for FRT. PFS at 5 years for GKRS, LinacRS, and FRT were respectively 93.6%, 95.6%, and 97.4% (p = 0.32, the Kruskal-Wallis). Monofractionated treatments (GKRS and LinacRS) induced more tumor volume regression than FRT (p = 0.001). Tumor recurrence or progression ranged between 3 and 5.8%, without statistically significant differences between modalities (p > 0.05). Trigeminal symptoms improved in approximately 54%, and III-IV-VI cranial nerves (CN) palsies improved in approximately 45%. After GKRS, visual acuity improved in 21% (not enough data available for other modalities). De novo deficits occurred in 5 to 7.5%. Adverse radiation effects appeared in 4.6 to 9.3% (all techniques pooled).

Conclusion: RS achieved a twice-higher rate of tumor volume regression than FRT. GKRS series reported an improvement in visual acuity in 21% of the cases. GKRS, Linac, and FRT provided similar clinical post therapeutic outcomes for the trigeminal and oculomotor CN.

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Skip Laminectomy Compared with Laminoplasty for Cervical Compressive Myelopathy

World Neurosurg. (2018) 120:296-301

This meta-analysis evaluated the clinical outcomes of skip laminectomy relative to laminoplasty for the treatment of cervical compressive myelopathy.

METHODS: The Cochrane library, PubMed MEDLINE, EMBASE, and Web of Science databases were comprehensively searched to identify relevant articles published up to March 18, 2018. All values of weighted mean difference (WMD) or odds ratio are expressed as skip laminectomy relative to laminoplasty.

RESULTS: Four studies comprising 241 patients were included. Skip laminectomy and laminoplasty were comparable in terms of cervical lordotic curvature (weighted mean difference [WMD] L2.37; 95% confidence interval [CI] L6.18 to 1.43; P [ 0.22) and range of motion (WMD e2.65; 95% CI L6.02 to 0.72; P [ 0.12). The pooled data revealed that the mean visual analogue scale score for pain of the skip laminectomy group was significantly lower than that of the laminoplasty group (WMD e0.97; 95% CI L1.90 to L0.05; P [ 0.04), and the rate of axial pain was also significantly lower (WMD 0.26; 95% CI 0.07e0.93; P [ 0.04). The atrophy rates of the deep extensor muscles in the skip laminectomy group (14%) were significantly lower than that of the laminoplasty group (60%).

CONCLUSIONS: This meta-analysis determined that skip laminectomy was superior to laminoplasty in terms of visual analogue scale score and rates of axial pain and muscle atrophy. These results warrant further confirmation in future research.

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Thirty-Day Outcomes After Craniotomy for Primary Malignant Brain Tumors

Neurosurgery 83:1249–1259, 2018

Despite improved perioperative management, the rate of postoperative morbidity and mortality after brain tumor resection remains considerably high.

OBJECTIVE: To assess the rates, causes, timing, and predictors of major complication, extended length of stay (>10 d), reoperation, readmission, and death within 30 d after craniotomy for primary malignant brain tumors.

METHODS: Patients were extracted from the National Surgical Quality Improvement Program registry (2005-2015) and analyzed using multivariable logistic regression.

RESULTS: A total of 7376 patientswere identified, ofwhich 948 (12.9%) experienced a major complication. The most common major complications were reoperation (5.1%), venous thromboembolism (3.5%), and death (2.6%). Furthermore, 15.6% stayed longer than 10 d, and 11.5% were readmitted within 30 d after surgery. The most common reasons for reoperation and readmission were intracranial hemorrhage (18.5%) and wound-related complications (11.9%), respectively. Multivariable analysis identified older age, higher body mass index, higher American Society of Anesthesiologists (ASA) classification, dependent functional status, elevated preoperative white blood cell count (white blood cell count [WBC], >12 000 cells/mm3), and longer operative time as predictors of major complication (all P < .001). Higher ASA classification, dependent functional status, elevated WBC, and ventilator dependence were predictors of extended length of stay (all P < .001). Higher ASA classification and elevatedWBCwere predictors of reoperation (both P<.001). Higher ASA classification and dependent functional status were predictors of readmission (both P < .001). Older age, higher ASA classification, and dependent functional status were predictors of death (all P< .001).

CONCLUSION: This study provides a descriptive analysis and identifies predictors for short term complications, including death, after craniotomy for primary malignant brain tumors.

 

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External validation of cerebral aneurysm rupture probability model with data from two patient cohorts

Acta Neurochirurgica (2018) 160:2425–2434

For a treatment decision of unruptured cerebral aneurysms, physicians and patients need to weigh the risk of treatment against the risk of hemorrhagic stroke caused by aneurysm rupture. The aim of this study was to externally evaluate a recently developed statistical aneurysm rupture probability model, which could potentially support such treatment decisions.

Methods Segmented image data and patient information obtained from two patient cohorts including 203 patients with 249 aneurysms were used for patient-specific computational fluid dynamics simulations and subsequent evaluation of the statistical model in terms of accuracy, discrimination, and goodness of fit. The model’s performance was further compared to a similaritybased approach for rupture assessment by identifying aneurysms in the training cohort that were similar in terms of hemodynamics and shape compared to a given aneurysm from the external cohorts.

Results When applied to the external data, the model achieved a good discrimination and goodness of fit (area under the receiver operating characteristic curve AUC = 0.82), which was only slightly reduced compared to the optimism-corrected AUC in the training population (AUC = 0.84). The accuracy metrics indicated a small decrease in accuracy compared to the training data (misclassification error of 0.24 vs. 0.21). The model’s prediction accuracy was improved when combined with the similarity approach (misclassification error of 0.14).

Conclusions The model’s performance measures indicated a good generalizability for data acquired at different clinical institutions. Combining the model-based and similarity-based approach could further improve the assessment and interpretation of new cases, demonstrating its potential use for clinical risk assessment.

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Surgical Clipping of Previously Ruptured, Coiled Aneurysms: Outcome Assessment in 53 Patients

World Neurosurg. (2018) 120:e203-e211

Occasionally, previously coiled aneurysms will require secondary treatment with surgical clipping, representing a more complicated aneurysm to treat than the naïve aneurysm. Patients who initially presented with a ruptured aneurysm may pose an even riskier group to treat than those with unruptured previously coiled aneurysms, given their potentially higher risk for rerupture. The objective of this study was to assess the clinical outcomes of patients who undergo microsurgical clipping of ruptured previously coiled cerebral aneurysms. In addition, we present a thorough review of the literature.

METHODS: A total of 53 patients from a single institution who initially presented with a subarachnoid hemorrhage and underwent surgical clipping of a previously coiled aneurysm between December 1997 and December 2014 were studied. Clinical features, hospital course, and preoperative and most recent functional status (Glasgow Outcome Scale score) were reviewed retrospectively.

RESULTS: The mean time interval from coiling to clipping was 2.6 years, and mean follow-up was 5.5 years (range, 0.1e14.7 years). Five patients (9.8%) presented with rebleed prior to clipping. Most patients (79.3%, 42/53) experienced good neurologic outcomes. Most showed no change (81%, 43/53) or improvement (13%, 7/53) in functional status after microsurgical clipping. One patient (2%) deteriorated clinically, and there were 2 mortalities (4%).

CONCLUSIONS: Microsurgical clipping of previously ruptured, coiled aneurysms is a promising treatment method with favorable clinical outcomes

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Enhancement of antitumor activity by using 5-ALA–mediated sonodynamic therapy to induce apoptosis in malignant gliomas

J Neurosurg 129:1416–1428, 2018

High invasiveness of malignant gliomas frequently causes early local recurrence of the tumor, resulting in extremely poor outcome. To control such recurrence, novel therapies targeted toward infiltrating glioma cells around the tumor border are required. Here, the authors investigated the antitumor activity of sonodynamic therapy (SDT) combined with a sonosensitizer, 5-aminolevulinic acid (5-ALA), on malignant gliomas to explore the possibility for clinical use of 5-ALA–mediated SDT (5-ALA-SDT).

METHODS In vitro cytotoxicity of 5-ALA-SDT was evaluated in U87 and U251 glioma cells and in U251Oct-3/4 glioma stemlike cells. Treatment-related apoptosis was analyzed using flow cytometry and TUNEL staining. Intracellular reactive oxygen species (ROS) were measured and the role of ROS in treatment-related cytotoxicity was examined by analysis of the effect of pretreatment with the radical scavenger edaravone. Effects of 5-ALA-SDT with high-intensity focused ultrasound (HIFU) on tumor growth, survival of glioma-transplanted mice, and histological features of the mouse brains were investigated.

RESULTS The 5-ALA-SDT inhibited cell growth and changed cell morphology, inducing cell shrinkage, vacuolization, and swelling. Flow cytometric analysis and TUNEL staining indicated that 5-ALA-SDT induced apoptotic cell death in all gliomas. The 5-ALA-SDT generated significantly higher ROS than in the control group, and inhibition of ROS generation by edaravone completely eliminated the cytotoxic effects of 5-ALA-SDT. In the in vivo study, 5-ALA-SDT with HIFU greatly prolonged survival of the tumor-bearing mice compared with that of the control group (p < 0.05). Histologically, 5-ALA-SDT produced mainly necrosis of the tumor tissue in the focus area and induced apoptosis of the tumor cells in the perifocus area around the target of the HIFU-irradiated field. The proliferative activity of the entire tumor was markedly decreased. Normal brain tissues around the ultrasonic irradiation field of HIFU remained intact.

CONCLUSIONS The 5-ALA-SDT was cytotoxic toward malignant gliomas. Generation of ROS by the SDT was thought to promote apoptosis of glioma cells. The 5-ALA-SDT with HIFU induced tumor necrosis in the focus area and apoptosis in the perifocus area of the HIFU-irradiated field, whereas the surrounding brain tissue remained normal, resulting in longer survival of the HIFU-treated mice compared with that of untreated mice. These results suggest that 5-ALA-SDT with HIFU may present a less invasive and tumor-specific therapy, not only for a tumor mass but also for infiltrating tumor cells in malignant gliomas.

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Endoscopic endonasal approach to primitive Meckel’s cave tumors

Acta Neurochirurgica (2018) 160:2349–2361

Recently, an alternative endoscopic endonasal approach to Meckel’s cave (MC) tumors has been proposed. To date, few studies have evaluated the results of this route. The aim of our study was to evaluate long-term surgical and clinical outcome associated with this technique in a cohort of patients with intrinsic MC tumors.

Methods All patients with MC tumors treated at out institution by endoscopic endonasal approach (EEA) between 2002 and 2016 were included. Patients underwent brain MRI, CT-angiography, and neurological evaluation before surgery. Complications were considered based on the surgical records. All examinations were repeated after 3 and 12 months, then annually. The median follow-up was of 44.1 months (range 16–210).

Results The series included 8 patients (4 F): 5 neuromas, 1 meningioma, 1 chondrosarcoma, and 1 epidermoid cyst. The median age at treatment was 54.5 years (range 21–70). Three tumors presented with a posterior fossa extension. Radical removal of the MC portion of the tumor was achieved in 7 out of 8 cases. Two patients developed a permanent and transitory deficit of the sixth cranial nerve, respectively. No tumor recurrence was observed at follow-up.

Conclusion In this preliminary series, the EEA appeared an effective and safe approach to MC tumors. The technique could be advantageous to treat tumors located in the antero-medial aspects of MC displacing the trigeminal structures posteriorly and laterally. A favorable index of an adequate working space for this approach is represented by the ICA medialization, while tumor extension to the posterior fossa represents the main limitation to radical removal of this route.

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Immediate Cranioplasty for Postcranioplasty Infection in Patients with Ventriculoperitoneal Shunt

World Neurosurg. (2018) 119:311-314

Patients with a ventriculoperitoneal (VP) shunt tend to develop epidural fluid accumulation after cranioplasty and also have a higher frequency of syndrome of the trephined after bone flap removal. Thus treatment of patients with postcranioplasty infection and a VP shunt is often challenging.

CASE DESCRIPTION: We treated 2 patients with postcranioplasty infection and a VP shunt. One patient had undergone decompressive craniectomy for cerebral hemorrhage, and the other patient had a large frontal dead space following resection of a brain tumor. Both patients were treated by immediate cranioplasty with obliteration of the epidural dead space by using a vascularized free latissimus dorsi muscle flap. In both of them, the postoperative course was uneventful without any complications.

CONCLUSIONS: Immediate cranioplasty and obliteration of the epidural dead space with a vascularized free latissimus dorsi muscle flap is an alternative for patients with postcranioplasty infection who are unfavorable candidates for temporary bone flap removal because of the risk of neurologic deterioration

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Predictors of Poor Outcome in Patients Submitted to Minimally Invasive Transforaminal Lumbar Interbody Fusion

World Neurosurg. (2018) 119:488-493

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) has become an increasingly popular method for lumbar arthrodesis. While having similar long-term outcomes when compared with open TLIF, it decreases the amount of intraoperative blood loss and iatrogenic muscle damage, the intensity of postoperative pain, and the duration of hospital stay. However, uncertainty remains about which factors contribute to outcomes in these patients. The purpose of this study was to retrospectively analyze a cohort of patients submitted to MI-TLIF and to identify factors that can be associated with a worse postoperative outcome.

METHODS: Clinical records from 283 patients were assessed and, according to Odom’s criteria, postoperative clinical outcome at 12 months was classified as excellent, good, fair, and poor. Demographic variables, clinical data, and surgery-related data were analyzed, looking for associations between them and clinical outcome. A binomial logistic regression analysis was then performed to include those associations.

RESULTS: The main variables associated with worse prognosis (“poor” class according to Odom’s criteria) were a period of sick leave longer than 3 months before the surgery, age younger than 50 years, lytic spondylolisthesis, L5-S1 level, and occurrence of complications. These 5 conditions were included in a logistic regression analysis, and 3 of them were independently associated with poor outcome: operative complications, age younger than 50 years, and sick leave longer than 3 months before surgery. –

CONCLUSIONS: Younger patients, those on a sick leave for more than 3 months before surgery, or those who suffered surgical complications tended to have less satisfactory results after MI-TLIF.

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Drivers of Variability in 90-Day Cost for Elective Anterior Cervical Discectomy and Fusion for Cervical Degenerative Disease

Neurosurgery 83:898–904, 2018

Value-based episode of care reimbursement models is being investigated to curb unsustainable health care costs. Any variation in the cost of index spine surgery can affect the payment bundling during the 90-d global period.

OBJECTIVE: To determine the drivers of variability in cost for patients undergoing elective anterior cervical discectomy and fusion (ACDF) for degenerative cervical spine disease.

METHODS: Four hundred forty-five patients undergoing elective ACDF for cervical spine degenerative diagnoses were included in the study. The direct 90-d cost was derived as sum of cost of surgery, cost associated with postdischarge utilization. Multiple variable linear regression models were built for total 90-d cost.

RESULTS: The mean 90-d direct cost was $17685 ± $5731. In a multiple variable linear regression model, the length of surgery, number of levels involved, length of hospital stay, preoperative history of anticoagulation medication, health-care resource utilization including number of imaging, any complications and readmission encounter were the significant contributor to the 90-d cost. The model performance as measured by R2 was 0.616.

CONCLUSION: There was considerable variation in total 90-d cost for elective ACDF surgery. Our model can explain about 62% of these variations in 90-d cost. The episode of care reimbursement models needs to take into account these variations and be inclusive of the factors that drive the variation in cost to develop a sustainable payment model. The generalized applicability should take in to account the differences in patient population, surgeons’ and institution-specific differences.

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Improving the aesthetic outcome with burr hole cover placement in chronic subdural hematoma evacuation

Acta Neurochirurgica (2018) 160:2129–2135

The aesthetic outcome after burr hole trepanation for the evacuation of chronic subdural hematomas (cSDH) is often unsatisfactory, as the bony skull defects may cause visible skin depressions. The purpose of this study was to evaluate the efficacy of burr hole cover placement to improve the aesthetic outcome.

Methods We reviewed consecutive patients treated by burr hole trepanation for cSDH with or without placement of burr hole covers by a single surgeon between October 2016 and May 2018. The clinical data, including complications, were derived from the institution’s prospective patient registry. The primary endpoint was the aesthetic outcome, as perceived by patients on the aesthetic numeric analog (ANA) scale, assessed by means of a standardized telephone interview. Secondary endpoints were skin depression rates and wound pain, as well as complications.

Results From n = 33, outcome evaluation was possible in n = 28 patients (n = 24 male; mean age of 70.4 ± 16.1 years) with uni- (n = 20) or bilateral cSDH (n = 8). A total of 14 burr hole covers were placed in 11 patients and compared to 50 burr holes that were not covered. Patient satisfaction with the aesthetic outcome was significantly better for covered burr holes (mean ANA 9.3 ± 0.74 vs. 7.9 ± 1.0; p < 0.001). Skin depressions occurred over 7% (n = 1/14) of covered and over 92%(n = 46/50) of uncovered burr holes (p < 0.001). There was no difference in wound pain (p = 0.903) between covered and uncovered sites. No surgical site infection, cSDH recurrence, or material failure was encountered in patients who had received a burr hole plate.

Conclusions In this retrospective series, placement of burr hole covers was associated with improved aesthetic outcome, likely due to reduction of skin depressions. A randomized controlled trial is developed to investigate whether adding burr hole covers results in superior aesthetic outcomes, without increasing the risk for complications.

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Reliable Identification of Benign Clinical Course in Aneurysmal Subarachnoid Hemorrhage

Neurosurgery 83:948–956, 2018

A reliable method to specifically identify low vasospasm risk in aneurysmal subarachnoid hemorrhage (aSAH) patients has not been previously proposed.

OBJECTIVE: To develop a clinical algorithm using admission aSAH clinical severity and subarachnoid blood distribution to identify patients at low risk of clinical vasospasm.

METHODS: Clinical severities, admission noncontrasted head computerized tomography (CT) scan, and incidences of vasospasm among 291 aSAH patients treated at our institutionwere evaluated. Admission head CTswere assessed for distributions of cisternal and ventricular blood. Patients with the following 4 criteria experienced considerably lower risk of vasospasm: (1) Hunt Hess grade 1 to 2, (2) Lack of thick subarachnoid blood filling 2 adjacent cisterns, (3) Lack of thick interhemispheric blood, and (4) Lack of biventricular intraventricular hemorrhage.

RESULTS: One hundred thirty-three patients (45.7%) developed cerebral vasospasm. Hunt Hess grade greater than 2 (odds ratio [OR] 4.52, 95% confidence interval [CI] 2.74-7.46), adjacent cistern blood (OR 4.1, 95% CI 2.51-6.7), interhemispheric thick blood (OR 5.72, 95% CI 3.41-9.59), and biventricular intraventricular hemorrhage (OR 1.92, 95% CI 1.19-3.02) were significant risk factors. Application of our algorithm yielded a sensitivity of 29%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 54.5%, which was superior compared to metrics from current institutional practice criteria. Inter-rater agreement was substantial at mean kappa = 0.75.

CONCLUSION: Application of our novel clinical algorithm produced successful identification of aSAH patients who experience zero risk of clinical vasospasm. Our algorithm is simple to apply with high reliability and is superior to currently available clinical and radiographic metrics.

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The relationship between repeat resection and overall survival in patients with glioblastoma: a time-dependent analysis

J Neurosurg 129:1231–1239, 2018

Previous studies assessed the relationship between repeat resection and overall survival (OS) in patients with glioblastoma, but ignoring the timing of repeat resection may have led to biased conclusions. Statistical methods that take time into account are well established and applied consistently in other medical fields. The goal of this study was to illustrate the change in the effect of repeat resection on OS in patients with glioblastoma once timing of resection is incorporated.

METHODS The authors conducted a retrospective study of patients initially diagnosed with glioblastoma between January 2005 and December 2014 who were treated at Memorial Sloan Kettering Cancer Center. Patients underwent at least 1 craniotomy with both pre- and postoperative MRI data available. The effect of repeat resection on OS was assessed with time-dependent extended Cox regression controlling for extent of resection, initial Karnofsky Performance Scale score, sex, age, multifocal status, eloquent status, and postoperative treatment.

RESULTS Eighty-nine (55%) of 163 patients underwent repeat resection with a median time between resections of 7.7 months (range 0.5–50.8 months). Median OS was 18.8 months (95% confidence interval [CI] 16.3–20.5 months) from initial resection. When timing of repeat resection was ignored, repeat resection was associated with a lower risk of death (hazard ratio [HR] 0.62, 95% CI 0.43–0.90, p = 0.01); however, when timing was taken into account, repeat resection was associated with a higher risk of death (HR 2.19, 95% CI 1.47–3.28, p < 0.001).

CONCLUSIONS In this study, accounting for timing of repeat resection reversed its protective effect on OS, suggesting repeat resection may not benefit OS in all patients. These findings establish a foundation for future work by accounting for timing of repeat resection using time-dependent methods in the evaluation of repeat resection on OS. Additional recommendations include improved data capture that includes mutational data, development of algorithms for determining eligibility for repeat resection, more rigorous statistical analyses, and the assessment of additional benefits of repeat resection, such as reduction of symptom burden and enhanced quality of life.

 

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Lateral lumbar interbody fusion in the elderly

J Neurosurg Spine 29:525–529, 2018

Elderly patients, often presenting with multiple medical comorbidities, are touted to be at an increased risk of peri- and postoperative complications following spine surgery. Various minimally invasive surgical techniques have been developed and employed to treat an array of spinal conditions while minimizing complications. Lateral lumbar interbody fusion (LLIF) is one such approach. The authors describe clinical outcomes in patients over the age of 70 years following stand-alone LLIF.

METHODS A retrospective query of a prospectively maintained database was performed for patients over the age of 70 years who underwent stand-alone LLIF. Patients with posterior segmental fixation and/or fusion were excluded. The preoperative and postoperative values for the Oswestry Disability Index (ODI) were analyzed to compare outcomes after intervention. Femoral neck t-scores were acquired from bone density scans and correlated with the incidence of graft subsidence.

RESULTS Among the study cohort of 55 patients, the median age at the time of surgery was 74 years (range 70–87 years). Seventeen patients had at least 3 medical comorbidities at surgery. Twenty-three patients underwent a 1-level, 14 a 2-level, and 18 patients a 3-level or greater stand-alone lateral fusion. The median estimated blood loss was 25 ml (range 5–280 ml). No statistically significant relationship was detected between volume of blood loss and the number of operative levels. The median length of hospital stay was 2 days (range 1–4 days). No statistically significant relationship was observed between the length of hospital stay and age at the time of surgery. There was one intraoperative death secondary to cardiac arrest, with a mortality rate of 1.8%. One patient developed a transient femoral nerve injury. Five patients with symptomatic graft subsidence subsequently underwent posterior instrumentation. A lower femoral neck t-score < -1.0 correlated with a higher incidence of graft subsidence (p = 0.006). The mean ODI score 1 year postoperatively of 31.1 was significantly (p = 0.003) less than the mean preoperative ODI score of 46.2.

CONCLUSIONS Stand-alone LLIF can be safely and effectively performed in the elderly population. Careful evaluation of preoperative bone density parameters should be employed to minimize risk of subsidence and need for additional surgery. Despite an association with increased comorbidities, age alone should not be a deterrent when considering stand-alone LLIF in the elderly population.

 

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Supratotal Resection of Diffuse Frontal Lower Grade Gliomas with Awake Brain Mapping, Preserving Motor, Language, and Neurocognitive Functions

World Neurosurg. (2018) 119:30-39

Extended margin tumor resection beyond the abnormal area detected by magnetic resonance imaging, defined as supratotal resection, could improve the outcomes of patients with lower grade gliomas (LGGs). The aim of the present study was to assess the surgical outcomes of awake brain mapping to achieve supratotal resection with determination of the normal brain tissue boundaries beyond the tumor of frontal LGGs, in both dominant and nondominant hemispheres.

METHODS: We analyzed the data from 9 patients with diffuse frontal LGGs who had undergone supratotal resection with awake surgery from January 2016 to November 2017.

RESULTS: The frontal aslant tract was identified as the functional boundary in 4 of 5 left frontal tumor cases (80%). Working memory impairments during dorsolateral prefrontal cortex stimulation with digit span and/or visual N-back tasks were detected in all 4 patients (100%) with right-frontal tumor. The neurocognitive outcomes were significantly improved after surgery, as shown by the mean Wechsler adult intelligence scale III scores for verbal intelligence quotient (P [ 0.04) and verbal comprehension (P [ 0.03) and the mean Wechsler memory scale-revised scores for generalized memory (P [ 0.04) and delayed recall (P [ 0.04).

CONCLUSIONS: The results of the present study have provided evidence that awake mapping can enable the preservation of higher neurocognitive function, including working memory and spatial cognition in patients with nondominant right frontal tumors. Despite the small number of cases, our findings suggest the surgical benefit of awake surgery for supratotal resection of diffuse frontal LGGs.

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The microneurosurgical anatomy legacy of Albert L. Rhoton Jr., MD: an analysis of transition and evolution over 50 years

J Neurosurg 129:1331–1341, 2018

Dr. Albert L. Rhoton Jr. was a pioneer of the study of microneurosurgical anatomy. Championing this field over the past half century, he produced more than 500 publications.

In this paper, the authors review his body of work, focusing on approximately 160 original articles authored by Rhoton and his microneuroanatomy fellows.

The articles are categorized chronologically into 5 stages: 1) dawn of microneurosurgical anatomy, 2) study of basic anatomy for general neurosurgery, 3) study for skull base surgery, 4) study of the internal structures of the brain by fiber dissection, and 5) surgical anatomy dealing with new advanced surgical approaches.

Rhoton introduced many new research ideas and surgical techniques and approaches, along with better microsurgery instruments, through studying and teaching microsurgical anatomy, especially during the first stage. The characteristic features of each stage are explained and the transition phases of his projects are reviewed.

 

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