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Jan-Karl Burkhardt, George F. Lasker, Ethan A. Winkler, Helen Kim and Michael T. Lawton

As the population ages, the question of how to manage brain arteriovenous malformations in the elderly becomes increasingly relevant. Is resection a reasonable option for these patients? In this study, the authors examined the outcomes of surgical patients 60 years or older and found that favorable outcomes were achieved with careful patient selection. Preoperative grading scales were more predictive of outcomes in patients older than 65 years than in those 60–65 years of age.

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Seungwon Yoon, Michael A. Mooney, Michael A. Bohl, John P. Sheehy, Peter Nakaji, Andrew S. Little and Michael T. Lawton

OBJECTIVE

With drastic changes to the health insurance market, patient cost sharing has significantly increased in recent years. However, the patient financial burden, or out-of-pocket (OOP) costs, for surgical procedures is poorly understood. The goal of this study was to analyze patient OOP spending in cranial neurosurgery and identify drivers of OOP spending growth.

METHODS

For 6569 consecutive patients who underwent cranial neurosurgery from 2013 to 2016 at the authors’ institution, the authors created univariate and multivariate mixed-effects models to investigate the effect of patient demographic and clinical factors on patient OOP spending. The authors examined OOP payments stratified into 10 subsets of case categories and created a generalized linear model to study the growth of OOP spending over time.

RESULTS

In the multivariate model, case categories (craniotomy for pain, tumor, and vascular lesions), commercial insurance, and out-of-network plans were significant predictors of higher OOP payments for patients (all p < 0.05). Patient spending varied substantially across procedure types, with patients undergoing craniotomy for pain ($1151 ± $209) having the highest mean OOP payments. On average, commercially insured patients spent nearly twice as much in OOP payments as the overall population. From 2013 to 2016, the mean patient OOP spending increased 17%, from $598 to $698 per patient encounter. Commercially insured patients experienced more significant growth in OOP spending, with a cumulative rate of growth of 42% ($991 in 2013 to $1403 in 2016).

CONCLUSIONS

Even after controlling for inflation, case-mix differences, and partial fiscal periods, OOP spending for cranial neurosurgery patients significantly increased from 2013 to 2016. The mean OOP spending for commercially insured neurosurgical patients exceeded $1400 in 2016, with an average annual growth rate of 13%. As patient cost sharing in health insurance plans becomes more prevalent, patients and providers must consider the potential financial burden for patients receiving specialized neurosurgical care.

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Fred G. Barker II

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Corinna C. Zygourakis, Janelle Lee, Julio Barba, Errol Lobo and Michael T. Lawton

OBJECTIVE

Concurrent surgeries, also known as “running two rooms” or simultaneous/overlapping operations, have recently come under intense scrutiny. The goal of this study was to evaluate the operative time and outcomes of concurrent versus nonconcurrent vascular neurosurgical procedures.

METHODS

The authors retrospectively reviewed 1219 procedures performed by 1 vascular neurosurgeon from 2012 to 2015 at the University of California, San Francisco. Data were collected on patient age, sex, severity of illness, risk of mortality, American Society of Anesthesiologists (ASA) status, procedure type, admission type, insurance, transfer source, procedure time, presence of resident or fellow in operating room (OR), number of co-surgeons, estimated blood loss (EBL), concurrent vs nonconcurrent case, severe sepsis, acute respiratory failure, postoperative stroke causing neurological deficit, unplanned return to OR, 30-day mortality, and 30-day unplanned readmission. For aneurysm clipping cases, data were also obtained on intraoperative aneurysm rupture and postoperative residual aneurysm. Chi-square and t-tests were performed to compare concurrent versus nonconcurrent cases, and then mixed-effects models were created to adjust for different procedure types, patient demographics, and clinical indicators between the 2 groups.

RESULTS

There was a significant difference in procedure type for concurrent (n = 828) versus nonconcurrent (n = 391) cases. Concurrent cases were more likely to be routine/elective admissions (53% vs 35%, p < 0.001) and physician referrals (59% vs 38%, p < 0.001). This difference in patient/case type was also reflected in the lower severity of illness, risk of death, and ASA class in the concurrent versus nonconcurrent cases (p < 0.01). Concurrent cases had significantly longer procedural times (243 vs 213 minutes) and more unplanned 30-day readmissions (5.7% vs 3.1%), but shorter mean length of hospital stay (11.2 vs 13.7 days), higher rates of discharge to home (66% vs 51%), lower 30-day mortality rates (3.1% vs 6.1%), lower rates of acute respiratory failure (4.3% vs 8.2%), and decreased 30-day unplanned returns to the OR (3.3% vs 6.9%; all p < 0.05). Rates of severe sepsis, postoperative stroke, intraoperative aneurysm rupture, and postoperative aneurysm residual were equivalent between the concurrent and nonconcurrent groups (all p values nonsignificant). Mixed-effects models showed that after controlling for procedure type, patient demographics, and clinical indicators, there was no significant difference in acute respiratory failure, severe sepsis, 30-day readmission, postoperative stroke, EBL, length of stay, discharge status, or intraoperative aneurysm rupture between concurrent and nonconcurrent cases. Unplanned return to the OR and 30-day mortality were significantly lower in concurrent cases (odds ratio 0.55, 95% confidence interval 0.31–0.98, p = 0.0431, and odds ratio 0.81, p < 0.001, respectively), but concurrent cases had significantly longer procedure durations (odds ratio 21.73; p < 0.001).

CONCLUSIONS

Overall, there was a significant difference in the types of concurrent versus nonconcurrent cases, with more routine/elective cases for less sick patients scheduled in an overlapping fashion. After adjusting for patient demographics, procedure type, and clinical indicators, concurrent cases had longer procedure times, but equivalent patient outcomes, as compared with nonconcurrent vascular neurosurgical procedures.

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Ali Tayebi Meybodi, Michael T. Lawton, Dylan Griswold, Pooneh Mokhtari, Andre Payman and Arnau Benet

OBJECTIVE

The anterior temporal artery (ATA) supplies an area of the brain that, if sacrificed, does not cause a noticeable loss of function. Therefore, the ATA may be used as a donor in intracranial-intracranial (IC-IC) bypass procedures. The capacities of the ATA as a donor have not been studied previously. In this study, the authors assessed the feasibility of using the ATA as a donor for revascularization of different segments of the distal middle cerebral artery (MCA).

METHODS

The ATA was studied in 15 cadaveric specimens (8 heads, excluding 1 side). First, the cisternal segment of the artery was untethered from arachnoid adhesions and small branches feeding the anterior temporal lobe and insular cortex, to evaluate its capacity for a side-to-side bypass to insular, opercular, and cortical segments of the MCA. Any branch entering the anterior perforated substance was preserved. Then, the ATA was cut at the opercular-cortical junction and the capacity for an end-to-side bypass was assessed.

RESULTS

From a total of 17 ATAs, 4 (23.5%) arose as an early MCA branch. The anterior insular zone and the frontal parasylvian cortical arteries were the best targets (in terms of mobility and caliber match) for a side-to-side bypass. Most of the insula was accessible for end-to-side bypass, but anterior zones of the insula were more accessible than posterior zones. End-to-side bypass was feasible for most recipient cortical arteries along the opercula, except for posterior temporal and parietal regions. Early ATAs reached significantly farther on the insular MCA recipients than non-early ATAs for both side-to-side and end-to-side bypasses.

CONCLUSIONS

The ATA is a robust arterial donor for IC-IC bypass procedures, including side-to-side and end-to-side techniques. The evidence provided in this work supports the use of the ATA as a donor for distal MCA revascularization in well-selected patients.

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Ali Tayebi Meybodi, Michael T. Lawton, Halima Tabani and Arnau Benet

OBJECTIVE

Surgical access to the lateral recess of the fourth ventricle (LR) is suboptimal with existing transvermian and telovelar approaches because of limited lateral exposure, significant retraction of the cerebellar tonsil, and steep trajectories near brainstem perforator arteries. The goal in this study was to assess surgical exposure of the tonsillobiventral fissure approach to the LR, and to describe the relevant anatomy.

METHODS

Two formaldehyde-fixed cerebella were used to study the anatomical relationships of the LR. Also, the tonsillobiventral fissure approach was simulated in 8 specimens through a lateral suboccipital craniotomy.

RESULTS

The pattern of the cerebellar folia and the cortical branches of the posterior inferior cerebellar artery were key landmarks to identifying the tonsillobiventral fissure. Splitting the tonsillobiventral fissure allowed a direct and safe surgical trajectory to the LR and into the cerebellopontine cistern. The proposed approach reduces cervical flexion and optimizes the surgical angle of attack.

CONCLUSIONS

The tonsillobiventral fissure approach is a feasible and effective option for exposing the LR. This approach has more favorable trajectories and positions for the patient and the surgeon, and it should be added to the armamentarium for lesions in this location.

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Ali Tayebi Meybodi, Wendy Huang, Arnau Benet, Olivia Kola and Michael T. Lawton

OBJECT

Management of complex aneurysms of the middle cerebral artery (MCA) can be challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with aneurysm obliteration. Various bypass techniques are available, but an algorithmic approach to classifying these lesions and determining the optimal bypass strategy has not been developed. The objective of this study was to propose a comprehensive and flexible algorithm based on MCA aneurysm location for selecting the best of multiple bypass options.

METHODS

Aneurysms of the MCA that required bypass as part of treatment were identified from a large prospectively maintained database of vascular neurosurgeries. According to its location relative to the bifurcation, each aneurysm was classified as a prebifurcation, bifurcation, or postbifurcation aneurysm.

RESULTS

Between 1998 and 2015, 30 patients were treated for 30 complex MCA aneurysms in 8 (27%) prebifurcation, 5 (17%) bifurcation, and 17 (56%) postbifurcation locations. Bypasses included 8 superficial temporal artery–MCA bypasses, 4 high-flow extracranial-to-intracranial (EC-IC) bypasses, 13 IC-IC bypasses (6 reanastomoses, 3 reimplantations, 3 interpositional grafts, and 1 in situ bypass), and 5 combination bypasses. The bypass strategy for prebifurcation aneurysms was determined by the involvement of lenticulostriate arteries, whereas the bypass strategy for bifurcation aneurysms was determined by rupture status. The location of the MCA aneurysm in the candelabra (Sylvian, insular, or opercular) determined the bypass strategy for postbifurcation aneurysms. No deaths that resulted from surgery were found, bypass patency was 90%, and the condition of 90% of the patients was improved or unchanged at the most recent follow-up.

CONCLUSIONS

The bypass strategy used for an MCA aneurysm depends on the aneurysm location, lenticulostriate anatomy, and rupture status. A uniform bypass strategy for all MCA aneurysms does not exist, but the algorithm proposed here might guide selection of the optimal EC-IC or IC-IC bypass technique.

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Brian P. Walcott, Jae Seung Bang, Omar Choudhri, Sirin Gandhi, Halima Tabani, Arnau Benet and Michael T. Lawton

A 46-year-old male presented with an incidentally discovered left ventricular body arteriovenous malformation (AVM). It measured 2 cm in diameter and had drainage via an atrial vein into the internal cerebral vein (Spetzler-Martin Grade III, Supplementary Grade 4). Preoperative embolization of the posterior medial choroidal artery reduced nidus size by 50%. Subsequently, he underwent a right-sided craniotomy for a contralateral transcallosal approach to resect the AVM. This case demonstrates strategic circumferential disconnection of feeding arteries (FAs) to the nidus, the use of aneurysm clips to control large FAs, and the use of dynamic retraction and importance of a generous callosotomy. Postoperatively, he was neurologically intact, and angiogram confirmed complete resection.

The video can be found here: https://youtu.be/j0778LfS3MI.

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Jason M. Davies and Michael T. Lawton

OBJECTIVE

Treatment of cerebrovascular malformations has grown in complexity with the development of multimodal approaches, including microsurgery, endovascular treatments, and radiosurgery. In spite of this changing standard of care, the provision of care continues across a variety of settings. The authors sought to determine the risk of adverse outcome after treatment of patients with vascular malformations in the US. Patient, surgeon, and hospital characteristics, including volume, were tested as potential outcome predictors.

METHODS

The authors examined data collected between 2000 and 2009 in the Nationwide Inpatient Sample (NIS) database, assessing safety, quality, and cost-effectiveness. They performed multivariate analyses of trends in microsurgical, radiosurgical, and endovascular treatment by hospital and surgeon volume, using death, routine discharge percentage, length of stay (LOS), complications, and hospital charges as end points. They further computed the value of care, which was defined as the ratio of the functional outcome (routine discharge percentage) to cost of care to the payer (hospital charges).

RESULTS

The authors identified 8227 patients with vascular malformations who were treated at US hospitals. Hospitals and surgeons were classified by yearly case volume. Compared with low-volume hospitals (2 or fewer cases/year), high-volume hospitals (16 or more cases/year) had shorter LOS (3 vs 2 days, p = 0.005), higher total charges ($37,374 vs $19,986, p = 0.003), more frequent discharge to home (p < 0.001), and lower mortality rates (0.7% vs 1.16%, p = 0.010). High-volume surgeons (7 or more cases/year) likewise had superior outcomes compared with low-volume surgeons (1 or fewer cases/year), with shorter LOS (2 vs 3 days, p = 0.03), more frequent discharge to home (p < 0.001), and lower mortality rates (0.7% vs 1.10%, p = 0.005). Underlying these outcomes, the rates of intervention for surgery, angiography, embolization, and radiosurgery were likewise significantly different in high- versus low-volume practices.

Based on these results the authors modeled how outcomes might change if care were consolidated at designated centers of excellence (COEs), and found that on an annual basis, care at high-volume hospital COEs would result in 18.5 fewer deaths, 1252.1 fewer hospital days, 182.7 more discharges home without additional services, 48.5 fewer medical complications, and 117.4 fewer perioperative complications. Surgeon-level rates for high-volume COEs demonstrated an even larger benefit over current standards, with 27.4 fewer deaths, 10,713.7 fewer hospital days, a $51.6-million reduction in charges, 370.9 additional routine discharges, and reduced complications in all categories (27.8 fewer surgical, 198.0 fewer medical, and 32.1 fewer perioperative) compared with care at non-COEs.

CONCLUSIONS

For patients with vascular malformations who were treated in the US between 2000 and 2009, treatment performed at high-volume centers was associated with significantly lower morbidity and, for high-volume surgeons, with lower mortality rates. These data suggest that treatment by high-volume institutions and surgeons will yield superior outcomes and superior value. The authors therefore advocate the creation of care paradigms that triage patients to high-volume institutions and surgeons, which can serve as cerebrovascular COEs.

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Robert M. Starke, Felipe C. Albuquerque and Michael T. Lawton

It is with great pleasure that we present this Neurosurgical Focus video supplement on supratentorial cerebral arteriovenous malformations (AVMs). We were privileged to view a remarkable number of outstanding videos demonstrating current state-of-the-art management of brain AVMs using endovascular and microsurgical modalities. Careful and critical review was required to narrow down the submitted videos to a workable volume for this supplement, which reflects the excellent work being done at multiple centers with these lesions.

This issue consists of videos that represent modern microsurgical and neuroendovascular techniques for the treatment of supratentorial cerebral AVMs. The videos demonstrate cutting-edge therapies as well as standard ones, which will be valuable to both novice and expert neurointerventionists and neurosurgeons. We are honored to be involved with this project and proud of its content and expert authors. We believe you will enjoy the video content of this supplement and hope that it will raise the collective expertise of our community of AVM surgeons.