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Vijay M. Ravindra, Robert J. Bollo, Ilyas M. Eli, Julius Griauzde, Arianna Lanpher, Jennifer Klein, Huirong Zhu, Douglas L. Brockmeyer, John R. W. Kestle, William T. Couldwell, R. Michael Scott and Edward Smith

OBJECTIVE

Large experiences with the treatment of pediatric arteriovenous malformations (AVMs) remain relatively rare, with limited data on presentation, treatment, and long-term functional outcomes. Because of the expected long lifespan of children, caregivers are especially interested in outcome measures that assess quality of life. The authors’ intention was to describe the long-term functional outcomes of pediatric patients who undergo AVM surgery and to identify predictors of sustained neurological deficits.

METHODS

The authors analyzed a 21-year retrospective cohort of pediatric patients with intracranial AVMs treated with microsurgery at two institutions. The primary outcome was a persistent neurological deficit at last follow-up. Secondary outcome measures included modified Rankin Scale (mRS) score and independent living.

RESULTS

Overall, 97 patients (mean age 11.1 ± 4.5 years; 56% female) were treated surgically for intracranial AVMs (mean follow-up 77.5 months). Sixty-four patients (66%) presented with hemorrhage, and 45 patients (46%) had neurological deficits at presentation. Radiologically, 39% of lesions were Spetzler-Martin grade II. Thirty-seven patients (38%) with persistent neurological deficits at last follow-up were compared with those without deficits; there were no differences in patient age, presenting Glasgow Coma Scale score, AVM size, surgical blood loss, or duration of follow-up. Multivariate analysis demonstrated that a focal neurological deficit on presentation, AVM size > 3 cm, and lesions in eloquent cortex were independent predictors of persistent neurological deficits at long-term follow-up. Overall, 92% of the children had an mRS score ≤ 2 on long-term follow-up.

CONCLUSIONS

Pediatric patients with AVMs treated with microsurgical resection have good functional and radiological outcomes. There is a high rate (38%) of persistent neurological deficits, which were independently predicted by preoperative deficits, AVMs > 3 cm, and lesions located in eloquent cortex. This information can be useful in counseling families on the likelihood of long-term neurological deficits after cerebral AVM surgery.

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Silvia Gesheva, William T. Couldwell, Vance Mortimer, Philipp Taussky and Ramesh Grandhi

Dural arteriovenous fistulae (dAVFs) are vascular anomalies formed by abnormal connections between branches of dural arteries and dural veins or dural venous sinus(es). These pathologic shunts constitute 10%–15% of all intracranial arteriovenous malformations. The hallmark of malignant dAVFs is the presence of cortical venous drainage, a finding that increases the likelihood of nonhemorrhagic neurologic deficit, intracranial hemorrhage, and mortality if left unaddressed. Endovascular approaches have become the primary modality for the treatment of dAVFs. The authors present a case of staged endovascular transarterial embolization of a malignant dAVF running parallel to the left transverse sinus in a patient with headaches and pulsatile tinnitus. The fistula was completely treated using Onyx and n-butyl cyanoacrylate.

The video can be found here: https://youtu.be/GSAto_wlC3I.

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Yair M. Gozal, Gmaan Alzhrani, Hussam Abou-Al-Shaar, Mohammed A. Azab, Michael T. Walsh and William T. Couldwell

OBJECTIVE

Cavernous sinus meningiomas are complex tumors that offer a perpetual challenge to skull base surgeons. The senior author has employed a management strategy for these lesions aimed at maximizing tumor control while minimizing neurological morbidity. This approach emphasizes combining “safe” tumor resection and direct decompression of the roof and lateral wall of the cavernous sinus as well as the optic nerve. Here, the authors review their experience with the application of this technique for the management of cavernous sinus meningiomas over the past 15 years.

METHODS

A retrospective analysis was performed for patients with cavernous sinus meningiomas treated over a 15-year period (2002–2017) with this approach. Patient outcomes, including cranial nerve function, tumor control, and surgical complications were recorded.

RESULTS

The authors identified 50 patients who underwent subtotal resection via frontotemporal craniotomy concurrently with decompression of the cavernous sinus and ipsilateral optic nerve. Of these, 25 (50%) underwent adjuvant radiation to the remaining tumor within the cavernous sinus. Patients most commonly presented with a cranial nerve (CN) palsy involving CN III–VI (70%), a visual deficit (62%), headaches (52%), or proptosis (44%). Thirty-five patients had cranial nerve deficits preoperatively. In 52% of these cases, the neuropathy improved postoperatively; it remained stable in 46%; and it worsened in only 2%. Similarly, 97% of preoperative visual deficits either improved or were stable postoperatively. Notably, 12 new cranial nerve deficits occurred postoperatively in 10 patients. Of these, half were transient and ultimately resolved. Finally, radiographic recurrence was noted in 5 patients (10%), with a median time to recurrence of 4.6 years.

CONCLUSIONS

The treatment of cavernous sinus meningiomas using surgical decompression with or without adjuvant radiation is an effective oncological strategy, achieving excellent tumor control rates with low risk of neurological morbidity.

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Al-Wala Awad, Craig Kilburg, Michael Karsy, William T. Couldwell and Philipp Taussky

OBJECTIVE

The Pipeline embolization device (PED) is a self-expanding mesh stent that diverts blood flow away from an aneurysm; it has been successfully used to treat aneurysms of the proximal internal carotid artery (ICA). PEDs have a remarkable ability to alter regional blood flow along the tortuous segments of the ICA and were incidentally found to alter the angle of the anterior genu after treatment. The authors quantified these changes and explored their implications as they relate to treatment effect.

METHODS

The authors retrospectively reviewed cases of aneurysms treated with a PED between the ophthalmic and posterior communicating arteries from 2012 through 2015. The angles of the anterior genu were measured on the lateral projections of cerebral angiograms obtained before and after treatment with a PED. The angles of the anterior genu of patients without aneurysms were used as normal controls.

RESULTS

Thirty-eight patients were identified who had been treated with a PED; 34 (89.5%) had complete obliteration and 4 (10.5%) had persistence of their aneurysm at last follow-up (mean 11.3 months). After treatment, 32 patients had an increase, 3 had a decrease, and 3 had no change in the angle of the anterior genu. The average measured angle of the anterior genu was 36.7° before treatment and 44.3° after treatment (p < 0.0001). The average angle of the anterior genu of control patients was 43.32° (vs 36.7° for the preoperative angle in the patients with aneurysms, p < 0.057). The average change in the angle of patients with postoperative Raymond scores of 1 was 9.10°, as compared with 1.25° in patients with postoperative Raymond scores > 1 (p < 0.001).

CONCLUSIONS

Treatment with a PED significantly changes the angle of the anterior genu. An average change of 9.1° was associated with complete obliteration of treated aneurysms. These findings have important implications for the treatment and management of cerebral aneurysm.

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Yair M. Gozal, Erinç Aktüre, Vijay M. Ravindra, Jonathan P. Scoville, Randy L. Jensen, William T. Couldwell and Philipp Taussky

OBJECTIVE

The absence of a commonly accepted standardized classification system for complication reporting confounds the recognition, objective reporting, management, and avoidance of perioperative adverse events. In the past decade, several classification systems have been proposed for use in neurosurgery, but these generally focus on tallying specific complications and grading their effect on patient morbidity. Herein, the authors propose and prospectively validate a new neurosurgical complication classification based on understanding the underlying causes of the adverse events.

METHODS

A new complication classification system was devised based on the authors’ previous work on morbidity in endovascular surgery. Adverse events were prospectively compiled for all neurosurgical procedures performed at their tertiary care academic medical center over the course of 1 year into 5 subgroups: 1) indication errors; 2) procedural errors; 3) technical errors; 4) judgment errors; and 5) critical events. The complications were presented at the monthly institutional Morbidity and Mortality conference where, following extensive discussion, they were assigned to one of the 5 subgroups. Additional subgroup analyses by neurosurgical subspecialty were also performed.

RESULTS

A total of 115 neurosurgical complications were observed and analyzed during the study period. Of these, nearly half were critical events, while technical errors accounted for approximately one-third of all complications. Within neurosurgical subspecialties, vascular neurosurgery (36.5%) had the most complications, followed by spine & peripheral nerve (21.7%), neuro-oncology (14.8%), cranial trauma (13.9%), general neurosurgery (12.2%), and functional neurosurgery (0.9%).

CONCLUSIONS

The authors’ novel neurosurgical complication classification system was successfully implemented in a prospective manner at their high-volume tertiary medical center. By employing the well-established Morbidity and Mortality conference mechanism, this simple system may be easily applied at other neurosurgical centers and may allow for uniform analyses of perioperative morbidity and the introduction of corrective initiatives.

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Spencer Twitchell, Michael Karsy, Yair M. Gozal, Christian Davidson, William T. Couldwell and Douglas Brockmeyer

Psammomatoid juvenile ossifying fibroma (PJOF) is an uncommon, benign fibro-osseous tumor. It is a purely surgical disease, and a review of the literature revealed that adjuvant therapies, including chemotherapy and radiation, play a limited role. The authors report the case of a 16-year-old male refugee who presented with a giant sinonasal PJOF with parasellar invasion, after having been unable to undergo earlier surgical treatment. The delay in presentation resulted in a large lesion with bilateral optic nerve compression, blindness, and frontal lobe compression. The patient was surgically treated with a two-stage combined cranial and endoscopic endonasal surgical approach. The delay in treatment and significant neurological compromise, which necessitated a two-stage approach, are unique from previously reported cases of PJOF.

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Hussam Abou-Al-Shaar, Mohammed A. Azab, Michael Karsy, Jian Guan, Gmaan Alzhrani, Yair M. Gozal, Randy L. Jensen and William T. Couldwell

OBJECTIVE

Microsurgical resection and radiosurgery remain the most widely used interventions in the treatment of vestibular schwannomas. There is a growing demand for cost-effectiveness analyses to evaluate these two treatment modalities and delineate the factors that drive their total costs. Here, the authors evaluated specific cost drivers for microsurgical and radiosurgical management of vestibular schwannoma by using the Value Driven Outcomes system available at the University of Utah.

METHODS

The authors retrospectively reviewed all cases involving microsurgical and radiosurgical treatment of vestibular schwannomas at their institution between November 2011 and September 2017. Patient and tumor characteristics, subcategory costs, and potential cost drivers were analyzed.

RESULTS

The authors identified 163 vestibular schwannoma cases, including 116 managed microsurgically and 47 addressed with stereotactic radiosurgery (SRS). There were significant differences between the two groups in age, tumor size, and preoperative Koos grade (p < 0.05), suggesting that indications for treatment were markedly different. Length of stay (LOS) and length of follow-up were also significantly different. Facility costs were the most significant contributor to both microsurgical and SRS groups (58.3% and 99.4%, respectively); however, physician professional fees were not specifically analyzed. As expected, microsurgical treatment resulted in an average 4-fold greater overall cost of treatment than for SRS cases (p < 0.05), and there was a greater variation in costs for open cases as well. Costs remained stable over time for both open resection and SRS. Multivariable analysis showed that LOS (β = 0.7, p = 0.0001), discharge disposition (β = 0.2, p = 0.004), nonserviceable hearing (β = 0.1, p = 0.02), and complications (β = 0.2, p = 0.005) affected cost for open surgery, whereas no specifically examined factor could be identified as driving costs for SRS.

CONCLUSIONS

This analysis identified the fact that facility utilization constitutes the majority of total costs for both microsurgery and SRS treatment modalities of vestibular schwannomas. LOS, discharge disposition, nonserviceable hearing, and complications contributed significantly to the total costs for the microsurgical group, whereas none of the factors could be identified as driving total costs for the SRS group. This information may be used to establish policies and protocols to reduce facility costs, with the goal of decreasing the total costs without jeopardizing patient care.

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Jian Guan, Michael Karsy, Andrea A. Brock, William T. Couldwell, John R. W. Kestle, Randy L. Jensen, Andrew T. Dailey, Erica F. Bisson and Richard H. Schmidt

OBJECTIVE

Overlapping surgery remains a controversial topic in the medical community. Although numerous studies have examined the safety profile of overlapping operations, there are few data on its financial impact. The authors assessed direct hospital costs associated with neurosurgical operations during periods before and after a more stringent overlapping surgery policy was implemented.

METHODS

The authors retrospectively reviewed the records of nonemergency neurosurgical operations that took place during the periods from June 1, 2014, to October 31, 2014 (pre–policy change), and from June 1, 2016, to October 31, 2016 (post–policy change), by any of the 4 senior neurosurgeons authorized to perform overlapping cases during both periods. Cost data as well as demographic, surgical, and hospitalization-related variables were obtained from an institutional tool, the Value-Driven Outcomes database.

RESULTS

A total of 625 hospitalizations met inclusion criteria for cost analysis; of these, 362 occurred prior to the policy change and 263 occurred after the change. All costs were reported as a proportion of the average total hospitalization cost for the entire cohort. There was no significant difference in mean total hospital costs between the prechange and postchange period (0.994 ± 1.237 vs 1.009 ± 0.994, p = 0.873). On multivariate linear regression analysis, neither the policy change (p = 0.582) nor the use of overlapping surgery (p = 0.273) was significantly associated with higher total hospital costs.

CONCLUSIONS

A more restrictive overlapping surgery policy was not associated with a reduction in the direct costs of hospitalization for neurosurgical procedures.

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Gmaan Alzhrani, Yair M. Gozal, Ilyas Eli, Walavan Sivakumar, Amol Raheja, Douglas L. Brockmeyer and William T. Couldwell

OBJECTIVE

Surgical treatment of pathological processes involving the ventral craniocervical junction (CCJ) traditionally involves anterior and posterolateral skull base approaches. In cases of bilateral extension, when lesions extend beyond the midline to the contralateral side, a unilateral corridor may result in suboptimal resection. In these cases, the lateral extent of the tumor will prevent extirpation of the lesion via anterior surgical approaches. The authors describe a unilateral operative corridor developed along an extreme lateral trajectory to the anterior aspect of the clival and upper cervical dura, allowing exposure and resection of tumor on the contralateral side. This approach is used when the disease involves the bone structures inherent to stability at the anterior CCJ.

METHODS

To achieve exposure of the ventral CCJ, an extreme lateral transcondylar transodontoid (ELTO) approach was performed with transposition of the ipsilateral vertebral artery, followed by drilling of the C1 anterior arch. Resection of the odontoid process allowed access to the contralateral component of lesions across the midline to the region of the extracranial contralateral vertebral artery, maximizing resection.

RESULTS

Exposure and details of the surgical procedure were derived from anatomical cadavers. At the completion of cadaveric dissection, morphometric measurements of the relevant anatomical landmarks were obtained. Illustrative case examples for approaching ventral CCJ chordomas via the ELTO approach are presented.

CONCLUSIONS

The ELTO approach provides a safe and direct surgical corridor to treat complex lesions at the ventral CCJ with bilateral extension through a single operative corridor. This approach can be combined with other lateral approaches or posterior infratemporal approaches to remove more extensive lesions involving the rostral clivus, jugular foramen, and temporal bone.

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Michael Karsy, Fraser Henderson Jr., Steven Tenny, Jian Guan, Jeremy W. Amps, Allan H. Friedman, Alejandro M. Spiotta, Sunil Patel, John R. W. Kestle, Randy L. Jensen and William T. Couldwell

OBJECTIVE

The analysis of resident research productivity in neurosurgery has gained significant recent interest. Resident scholarly output affects departmental productivity, recruitment of future residents, and likelihood of future research careers. To maintain and improve opportunities for resident research, the authors evaluated factors that affect resident attitudes toward neurosurgical research on a national level.

METHODS

An online survey was distributed to all US neurosurgical residents. Questions assessed interest in research, perceived departmental support of research, and resident-perceived limitations in pursuing research. Residents were stratified based on number of publications above the median (AM; ≥ 14) or below the median (BM; < 14) for evaluation of factors influencing productivity.

RESULTS

A total of 278 resident responses from 82 US residency programs in 30 states were included (a 20% overall response rate). Residents predominantly desired future academic positions (53.2%), followed by private practice with some research (40.3%). Residents reported a mean ± SD of 11 ± 14 publications, which increased with postgraduate year level. The most common type of research involved retrospective cohort studies (24%) followed by laboratory/benchtop (19%) and case reports (18%). Residents as a group spent on average 14.1 ± 18.5 hours (median 7.0 hours) a week on research. Most residents (53.6%) had ≥ 12 months of protected research time. Mentorship (92.4%), research exposure (89.9%), and early interest in science (78.4%) had the greatest impact on interest in research while the most limiting factors were time (91.0%), call scheduling (47.1%), and funding/grants (37.1%). AM residents cited research exposure (p = 0.003), neurosurgery conference exposure (p = 0.02), formal research training prior to residency (p = 0.03), internal funding sources (p = 0.05), and software support (p = 0.02) as most important for their productivity. Moreover, more productive residents applied and received a higher number of < $10,000 and ≥ $10,000 grants (p < 0.05). A majority of residents (82.4%) agreed or strongly agreed with pursuing research throughout their professional careers. Overall, about half of residents (49.6%) were encouraged toward continued neurosurgical research, while the rest were neutral (36.7%) or discouraged (13.7%). Free-text responses helped to identify solutions on a departmental, regional, and national level that could increase interest in neurosurgical research.

CONCLUSIONS

This survey evaluates various factors affecting resident views toward research, which may also be seen in other specialties. Residents remain enthusiastic about neurosurgical research and offer several solutions to the ever-scarce commodities of time and funding within academic medicine.