OBJECTIVE

Physicians are more frequently encountering patients who are treated with deep brain stimulation (DBS), yet many MRI centers do not routinely perform MRI in this population. This warrants a safety assessment to improve DBS patients’ accessibility to MRI, thereby improving their care while simultaneously providing a new tool for neuromodulation research.

METHODS

A phantom simulating a patient with a DBS neuromodulation device (DBS lead model 3387 and IPG Activa PC model 37601) was constructed and used. Temperature changes at the most ventral DBS electrode contacts, implantable pulse generator (IPG) voltages, specific absorption rate (SAR), and B1+rms were recorded during 3-T MRI scanning. Safety data were acquired with a transmit body multi-array receive and quadrature transmit-receive head coil during various pulse sequences, using numerous DBS configurations from “the worst” to “the most common.”

In addition, 3-T MRI scanning (T1 and fMRI) was performed on 41 patients with fully internalized and active DBS using a quadrature transmit-receive head coil. MR images, neurological examination findings, and stability of the IPG impedances were assessed.

RESULTS

In the phantom study, temperature rises at the DBS electrodes were less than 2°C for both coils during 3D SPGR, EPI, DTI, and SWI. Sequences with intense radiofrequency pulses such as T2-weighted sequences may cause higher heating (due to their higher SAR). The IPG did not power off and kept a constant firing rate, and its average voltage output was unchanged. The 41 DBS patients underwent 3-T MRI with no adverse event.

CONCLUSIONS

Under the experimental conditions used in this study, 3-T MRI scanning of DBS patients with selected pulse sequences appears to be safe. Generally, T2-weighted sequences (using routine protocols) should be avoided in DBS patients. Complementary 3-T MRI phantom safety data suggest that imaging conditions that are less restrictive than those used in the patients in this study, such as using transmit body multi-array receive coils, may also be safe. Given the interplay between the implanted DBS neuromodulation device and the MRI system, these findings are specific to the experimental conditions in this study.

OBJECTIVE

Stem cell therapy is a promising strategy for the treatment of severe cerebral ischemia. However, targeting sufficient grafted cells to the affected area remains challenging. Choosing an adequate transplantation method for the CNS appears crucial for this therapy to become a clinical reality. The authors used a scaffold-free cell sheet as a translational intervention. This method involves the use of cell sheet layers and allows the transplantation of a large number of cells, locally and noninvasively. The authors evaluated the effectiveness of allogeneic adipose tissue–derived mesenchymal stem cell sheets in a rat model of stroke.

METHODS

The animals, subjected to middle cerebral artery occlusion, were randomly divided in two groups: one in which a cell sheet was transplanted and the other in which a vehicle was used (n = 10/group). Over a period of 14 days after transplantation, the animals’ behavior was evaluated, after which brain tissue samples were removed and fixed, and the extent of angiogenesis and infarct areas was evaluated histologically.

RESULTS

Compared to the vehicle group, in the cell sheet group functional angiogenesis and neurogenesis were significantly increased, which resulted in behavioral improvement. Transplanted cells were identified within newly formed perivascular walls as pericytes, a proportion of which were functional. Newly formed blood vessels were found within the cell sheet that had anastomosed to the cerebral blood vessels in the host.

CONCLUSIONS

The transplantation approach described here is expected to provide not only a paracrine effect but also a direct cell effect resulting in cell replacement that protects the damaged neurovascular unit. The behavioral improvement seen with this transplantation approach provides the basis for further research on cell sheet–based regenerative treatment as a translational treatment for patients with stroke.

OBJECTIVE

The aim of this study was to evaluate the effect of lumbar sacralization on the level of vertebral slip and disc degeneration in patients with L4 spondylolysis.

METHODS

The authors analyzed data from 102 cases in which patients underwent surgical treatment for L4 spondylolysis and spondylolisthesis at their institution between March 2007 and September 2016. Lumbar sacralization was characterized by the presence of pseudarthrosis and/or bony fusion between the L5 transverse process and sacrum, and the type of lumbosacral transitional vertebra (LSTV) was evaluated with the Castellvi classification. The amount of vertebral slippage was measured using the Taillard technique and Meyerding grade. Degeneration of the L4–5 segment was quantified using the Pfirrmann and Modic classifications. Patients were divided into 2 groups based on the presence or absence of sacralization, and the amount of vertebral slip and degeneration of the L4–5 segment was compared between groups.

RESULTS

Lumbar sacralization was present in 37 (36%) of 102 patients with L4 spondylolysis. The LSTV was type IIa in 10 cases, type IIb in 7, type IIIa in 2, and type IIIb in 18. The levels of vertebral slip and disc degeneration in the group of patients with sacralization were significantly greater than in the group without sacralization. No significant difference was found between the 2 groups with respect to Modic changes.

CONCLUSIONS

The increased stability between a sacralized L5 and the sacrum may predispose the L4–5 segment to greater instability and disc degeneration in patients with L4 spondylolysis.

OBJECTIVE

The shunt protocol developed by the Hydrocephalus Clinical Research Network (HCRN) was shown to significantly reduce shunt infections in children. However, its effectiveness had not been validated in a non-HCRN, small- to medium-volume pediatric neurosurgery center. The present study evaluated whether the 9-step Calgary Shunt Protocol, closely adapted from the HCRN shunt protocol, reduced shunt infections in children.

METHODS

The Calgary Shunt Protocol was prospectively applied at Alberta Children’s Hospital from May 23, 2013, to all children undergoing any shunt procedure. The control cohort consisted of children undergoing shunt surgery between January 1, 2009, and the implementation of the Calgary Shunt Protocol. The primary outcome was the strict HCRN definition of shunt infection. Univariate analyses of the protocol, individual elements within, and known confounders were performed using Student t-test for measured variables and chi-square tests for categorical variables. Multivariable logistic regression was performed using stepwise analysis.

RESULTS

Two-hundred sixty-eight shunt procedures were performed. The median age of patients was 14 months (IQR 3–61), and 148 (55.2%) were male. There was a significant absolute risk reduction of 10.0% (95% CI 3.9%–15.9%) in shunt infections (12.7% vs 2.7%, p = 0.004) after implementation of the Calgary Shunt Protocol. In univariate analyses, chlorhexidine was associated with fewer shunt infections than iodine-based skin preparation solution (4.1% vs 12.3%, p = 0.02). Waiting ≥ 20 minutes between receiving preoperative antibiotics and skin incision was also associated with a reduction in shunt infection (4.5% vs 14.2%, p = 0.007). In the multivariable analysis, only the overall protocol independently reduced shunt infections (OR 0.19 [95% CI 0.06–0.67], p = 0.009), while age, etiology, procedure type, ventricular catheter type, skin preparation solution, and time from preoperative antibiotics to skin incision were not significant.

CONCLUSIONS

This study externally validates the published HCRN protocol for reducing shunt infection in an independent, non-HCRN, and small- to medium-volume pediatric neurosurgery setting. Implementation of the Calgary Shunt Protocol independently reduced shunt infection risk. Chlorhexidine skin preparation and waiting ≥ 20 minutes between administration of preoperative antibiotic and skin incision may have contributed to the protocol’s quality improvement success.

OBJECTIVE

Safety-net hospitals deliver care to a substantial share of vulnerable patient populations and are disproportionately impacted by hospital payment reform policies. Complex elective procedures performed at safety-net facilities are associated with worse outcomes and higher costs. The effects of hospital safety-net burden on highly specialized, emergent, and resource-intensive conditions are poorly understood. The authors examined the effects of hospital safety-net burden on outcomes and costs after emergent neurosurgical intervention for ruptured cerebral aneurysms.

METHODS

The authors conducted a retrospective analysis of the Nationwide Inpatient Sample (NIS) from 2002 to 2011. Patients ≥ 18 years old who underwent emergent surgical clipping and endovascular coiling for aneurysmal subarachnoid hemorrhage (SAH) were included. Safety-net burden was defined as the proportion of Medicaid and uninsured patients treated at each hospital included in the NIS database. Hospitals that performed clipping and coiling were stratified as low-burden (LBH), medium-burden (MBH), and high-burden (HBH) hospitals.

RESULTS

A total of 34,647 patients with ruptured cerebral aneurysms underwent clipping and 23,687 underwent coiling. Compared to LBHs, HBHs were more likely to treat black, Hispanic, Medicaid, and uninsured patients (p < 0.001). HBHs were also more likely to be associated with teaching hospitals (p < 0.001). No significant differences were observed among the burden groups in the severity of subarachnoid hemorrhage. After adjusting for patient demographics and hospital characteristics, treatment at an HBH did not predict in-hospital mortality, poor outcome, length of stay, costs, or likelihood of a hospital-acquired condition.

CONCLUSIONS

Despite their financial burden, safety-net hospitals provide equitable care after surgical clipping and endovascular coiling for ruptured cerebral aneurysms and do not incur higher hospital costs. Safety-net hospitals may have the capacity to provide equitable surgical care for highly specialized emergent neurosurgical conditions.

OBJECTIVE

Endovascular treatment in children, especially neonates, can be more challenging than analogous procedures in adults. This study aimed to describe the clinical and radiological findings, type and timing of endovascular treatment, and early outcomes in children who present with neurovascular malformations, who are treated with embolization, and who weigh less than 5 kg.

METHODS

The authors carried out a retrospective review of all consecutively treated children weighing less than 5 kg with neurovascular arteriovenous malformations (AVMs) at a single institution over a 10-year period.

RESULTS

Fifty-two patients were included in the study. Thirty-eight had a vein of Galen aneurysmal malformation, 3 a pial AVM, 6 a pial arteriovenous fistula, and 5 a dural sinus malformation. The endovascular treatment goals were control of cardiac failure or hydrocephalus in cases of nonhemorrhagic malformations or to prevent new bleeding in cases of previous hemorrhage. A hemorrhagic complication occurred in 12 procedures and an ischemic complication in 2. Both complication types were correlated with the age of the infant (age cutoff at 3 months) (p = of 0.015 and 0.049, respectively). No correlation was found with the weight of the infant or the duration of the procedure.

CONCLUSIONS

The embolization of AVMs in these patients prevented adverse cardiac effects, hydrovenous disorders, and rebleeding. The risk of major cerebral complications seems mainly correlated with age, with a threshold at 3 months. A multidisciplinary team involved in the treatment of these children may help to improve treatment success and management.

OBJECTIVE

The evolution of microsurgical and endoscopic techniques has allowed the development of less invasive transcranial approaches. The authors describe a purely endoscopic transpterional port craniotomy to access lesions involving the cavernous sinus and the anterolateral skull base.

METHODS

Through single- or dual-port incisions and with direct endoscopic visualization, the authors performed an endoscopic transpterional port approach (ETPA) using a 4-mm straight endoscope in 8 sides of 4 formalin-fixed cadaveric heads injected with colored latex. A main working port incision is made just below the superior temporal line and behind the hairline. An optional 0.5- to 1-cm second skin port incision is made on the lateral supraorbital region, allowing multiangle endoscopic visualization and maneuverability. A 1.5- to 2-cm craniotomy centered over the pterion is done through the main port, which allows an extradural exposure of the cavernous sinus region and extra/intradural exposure of the frontal and temporal cranial fossae. The authors present a pilot surgical series of 17 ETPA procedures and analyze the surgical indications and clinical outcomes retrospectively.

RESULTS

The initial stage of this work on cadavers provided familiarity with the technique, standardized its steps, and showed its anatomical limits. The clinical ETPA was applied to gain access into the cavernous sinus, as well as for aneurysm clipping and meningioma resection. Overall, perioperative complications occurred in 1 patient (6%), there was no mortality, and at last follow-up all patients had a modified Rankin Scale score of 0 or 1.

CONCLUSIONS

The ETPA provides a less invasive, focused, and direct route to the cavernous sinus, and to the frontal and temporal cranial fossae, and it is feasible in clinical practice for selected indications with good results.