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Richard W. Williamson, David A. Wilson, Adib A. Abla, Cameron G. McDougall, Peter Nakaji, Felipe C. Albuquerque, and Robert F. Spetzler

OBJECT

Subarachnoid hemorrhage (SAH) from ruptured posterior inferior cerebellar artery (PICA) aneurysms is uncommon, and long-term outcome data for patients who have suffered such hemorrhages is lacking. This study investigated in-hospital and long-term clinical data from a prospective cohort of patients with SAH from ruptured PICA aneurysms enrolled in a randomized trial; their outcomes were compared with those of SAH patients who were treated for other types of ruptured intracranial aneurysms. The authors hypothesize that PICA patients fare worse than those with aneurysms in other locations and this difference is related to the high rate of lower cranial nerve dysfunction in PICA patients.

METHODS

The authors analyzed data for 472 patients enrolled in the Barrow Ruptured Aneurysm Trial (BRAT) and retrospectively reviewed vasospasm data not collected prospectively. In the initial cohort, 57 patients were considered angiographically negative for aneurysmal SAH source and did not receive treatment for aneurysms, leaving 415 patients with aneurysmal SAH.

RESULTS

Of 415 patients with aneurysmal SAH, 22 (5.3%) harbored a ruptured PICA aneurysm. Eight of them had dissecting/fusiform-type aneurysms while 14 had saccular-type aneurysms. Nineteen PICA patients were treated with clipping (1 crossover from coiling), 2 were treated with coiling, and 1 died before treatment. When comparing PICA patients to all other aneurysm patients in the study cohort, there were no statistically significant differences in age (mean 57.6 ± 11.8 vs 53.9 ± 11.8 years, p = 0.17), Hunt and Hess grade median III [IQR II–IV] vs III [IQR II–III], p = 0.15), Fisher grade median 3 [IQR 3–3] vs 3 [IQR 3–3], p = 0.53), aneurysm size (mean 6.2 ± 3.0 vs 6.7 ± 4.0 mm, p = 0.55), radiographic vasospasm (53% vs 50%, p = 0.88), or clinical vasospasm (12% vs 23%, p = 0.38). PICA patients were more likely to have a fusiform aneurysm (36% vs 12%, p = 0.004) and had a higher incidence of lower cranial nerve dysfunction and higher rate of tracheostomy/percutaneous endoscopic gastrostomy placement compared with non-PICA patients (50% vs 16%, p < 0.001). PICA patients had a significantly higher incidence of poor outcome at discharge (91% vs 67%, p = 0.017), 1-year follow-up (63% vs 29%, p = 0.002), and 3-year follow-up (63% vs 32%, p = 0.006).

CONCLUSIONS

Patients with ruptured PICA aneurysms had a similar rate of radiographic vasospasm, equivalent admission Fisher grade and Hunt and Hess scores, but poorer clinical outcomes at discharge and at 1- and 3-year follow-up when compared with the rest of the BRAT SAH patients with ruptured aneurysms. The PICA's location at the medulla and the resultant high rate of lower cranial nerve dysfunction may play a role in the poor outcome for these patients. Furthermore, PICA aneurysms were more likely to be fusiform than saccular, compared with non-PICA aneurysms; the complex nature of these aneurysms may also contribute to their poorer outcome.

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Christopher Roark, David Case, Mark Gritz, Patrick Hosokawa, David Kumpe, Joshua Seinfeld, Craig A. Williamson, and Anne M. Libby

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (aSAH) has devastating consequences. The association between higher institutional volumes and improved outcomes for aSAH patients has been studied extensively. However, the literature exploring patterns of transfer in this context is sparse. Expansion of the endovascular workforce has raised concerns about the decentralization of care, reduced institutional volumes, and worsened patient outcomes. In this paper, the authors explored various patient and hospital factors associated with the transfer of aSAH patients by using a nationally representative database.

METHODS

The 2013 and 2014 years of the National Inpatient Sample (NIS) were used to define an observational cohort of patients with ruptured brain aneurysms. The initial search identified patients with SAH (ICD-9-CM 430). Those with concomitant codes suggesting trauma or other intracranial vascular abnormalities were excluded. Finally, the patients who had not undergone a subsequent procedure to repair an intracranial aneurysm were excluded. These criteria yielded a cohort of 4373 patients, 1379 of whom had undergone microsurgical clip ligation and 2994 of whom had undergone endovascular repair. The outcome of interest was transfer status, and the NIS data element TRAN_IN was used to define this state. Multiple explanatory variables were identified, including age, sex, primary payer, median household income by zip code, race, hospital size, hospital control, hospital teaching status, and hospital location. These variables were evaluated using descriptive statistics, bivariate correlation analysis, and multivariable logistic regression modeling to determine their relationship with transfer status.

RESULTS

Patients with aSAH who were treated in an urban teaching hospital had higher odds of being a transfer (OR 2.15, 95% CI 1.71–2.72) than the patients in urban nonteaching hospitals. White patients were more likely to be transfer patients than were any of the other racial groups (p < 0.0001). Moreover, patients who lived in the highest-income zip codes were less likely to be transferred than the patients in the lowest income quartile (OR 0.78, 95% CI 0.64–0.95). Repair type (clip vs coil) and primary payer were not associated with transfer status.

CONCLUSIONS

A relatively high percentage of patients with aSAH are transferred between acute care hospitals. Race and income were associated with transfer status. White patients are more likely to be transferred than other races. Patients from zip codes with the highest income transferred at lower rates than those from the lowest income quartile. Transfer patients were preferentially sent to urban teaching hospitals. The modality of aneurysm treatment was not associated with transfer status.

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Adib A. Abla, David A. Wilson, Richard W. Williamson, Peter Nakaji, Cameron G. McDougall, Joseph M. Zabramski, Felipe C. Albuquerque, and Robert F. Spetzler

Object

Cerebral vasospasm following subarachnoid hemorrhage (SAH) causes significant morbidity in a delayed fashion. The authors recently published a new scale that grades the maximum thickness of SAH on axial CT and is predictive of vasospasm incidence. In this study, the authors further investigate whether different aneurysm locations result in different SAH clot burdens and whether any concurrent differences in ruptured aneurysm location and maximum SAH clot burden affect vasospasm incidence.

Methods

Two hundred fifty patients who were part of a prospective randomized controlled trial were reviewed. Most outcome and demographic variables were included as part of the prospective randomized controlled trial. Additional variables were also collected at a later time, including vasospasm data and maximum clot thickness.

Results

Aneurysms were categorized into 1 of 6 groups: intradural internal carotid artery aneurysms, vertebral artery (VA) aneurysms (including the posterior inferior cerebellar artery), basilar trunk or basilar apex aneurysms, middle cerebral artery aneurysms, pericallosal aneurysms, and anterior communicating artery aneurysms. Twenty-nine patients with nonaneurysmal SAH were excluded. Patients with pericallosal aneurysms had the least average maximum clot burden (5.3 mm), compared with 6.4 mm for the group overall, but had the highest rate of symptomatic vasospasm (56% vs 22% overall, OR 4.9, RR 2.7, p = 0.026). Symptomatic vasospasm occurrence was tallied in patients with clinical deterioration attributable to delayed cerebral ischemia. There were no significant differences in maximum clot thickness between aneurysm sites. Middle cerebral artery aneurysms resulted in the thickest mean maximum clot (7.1 mm) but rates of symptomatic and radiographic vasospasm in this group were statistically no different compared with the overall group. Vertebral artery aneurysms had the worst 1-year modified Rankin scale (mRS) scores (3.0 vs 1.9 overall, respectively; p = 0.0249). A 1-year mRS score of 0–2 (good outcome) was found in 72% of patients overall, but in only 50% of those with pericallosal and VA aneurysms, and in 56% of those with basilar artery aneurysms (p = 0.0044). Patients with stroke from vasospasm had higher mean clot thickness (9.71 vs 6.15 mm, p = 0.004).

Conclusions

The location of a ruptured aneurysm minimally affects the maximum thickness of the SAH clot but is predictive of symptomatic vasospasm or clinical deterioration from delayed cerebral ischemia in pericallosal aneurysms. The worst 1-year mRS outcomes in this cohort of patients were noted in those with posterior circulation aneurysms or pericallosal artery aneurysms. Patients experiencing stroke had higher mean clot burden.

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William J. Spire, Barbara C. Jobst, Vijay M. Thadani, Peter D. Williamson, Terrance M. Darcey, and David W. Roberts

Object

The authors describe their experience with a technique for robotic implantation of depth electrodes in patients concurrently undergoing craniotomy and placement of subdural monitoring electrodes for the evaluation of intractable epilepsy.

Methods

Patients included in this study underwent evaluation in the Dartmouth Surgical Epilepsy Program and were recommended for invasive seizure monitoring with depth electrodes between 2006 and the present. In all cases an image-guided robotic system was used during craniotomy for concurrent subdural grid electrode placement. A total of 7 electrodes were placed in 4 patients within the time period.

Results

Three of 4 patients had successful localization of seizure onset, and 2 underwent subsequent resection. Of the patients who underwent resection, 1 is now seizure free, and the second has only auras. There was 1 complication after subpial grid placement but no complications related to the depth electrodes.

Conclusions

Robotic image-guided placement of depth electrodes with concurrent craniotomy is feasible, and the technique is safe, accurate, and efficient.

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Alexandrine Gagnon, Mathieu Laroche, David Williamson, Marc Giroux, Jean-François Giguère, and Francis Bernard

OBJECTIVE

After craniectomy, although intracranial pressure (ICP) is controlled, episodes of brain hypoxia might still occur. Cerebral hypoxia is an indicator of poor outcome independently of ICP and cerebral perfusion pressure. No study has systematically evaluated the incidence and characteristics of brain hypoxia after craniectomy. The authors’ objective was to describe the incidence and characteristics of brain hypoxia after craniectomy.

METHODS

The authors included 25 consecutive patients who underwent a craniectomy after traumatic brain injury or intracerebral hemorrhage and who were monitored afterward with a brain tissue oxygen pressure monitor.

RESULTS

The frequency of hypoxic values after surgery was 14.6% despite ICP being controlled. Patients had a mean of 18 ± 23 hypoxic episodes. Endotracheal (ET) secretions (17.4%), low cerebral perfusion pressure (10.3%), and mobilizing the patient (8.6%) were the most common causes identified. Elevated ICP was rarely identified as the cause of hypoxia (4%). No cause of cerebral hypoxia could be determined 31.2% of the time. Effective treatments that were mainly used included sedation/analgesia (20.8%), ET secretion suctioning (15.4%), and increase in fraction of inspired oxygen or positive end-expiratory pressure (14.1%).

CONCLUSIONS

Cerebral hypoxia is common after craniectomy, despite ICP being controlled. ET secretion and patient mobilization are common causes that are easily treatable and often not identified by standard monitoring. These results suggest that monitoring should be pursued even if ICP is controlled. The authors’ findings might provide a hypothesis to explain the poor functional outcome in the recent randomized controlled trials on craniectomy after traumatic brain injury where in which brain tissue oxygen pressure was not measured.

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Laura Dellazizzo, Simon-Pierre Demers, Emmanuel Charbonney, Virginie Williams, Karim Serri, Martin Albert, Jean-François Giguère, Mathieu Laroche, David Williamson, and Francis Bernard

OBJECTIVE

Avoiding decreases in brain tissue oxygenation (PbtO2) after traumatic brain injury (TBI) is important. How best to adjust PbtO2 remains unclear. The authors investigated the association between partial pressure of oxygen (PaO2) and PbtO2 to determine the minimal PaO2 required to maintain PbtO2 above the hypoxic threshold (> 20 mm Hg), accounting for other determinants of PbtO2 and repeated measurements in the same patient. They also explored the clinical utility of a novel concept, the brain oxygenation ratio (BOx ratio = PbtO2/PaO2) to detect overtreatment with the fraction of inspired oxygen (FiO2).

METHODS

A retrospective cohort study at an academic level 1 trauma center included 38 TBI patients who required the insertion of a monitor to measure PbtO2. Various determinants of PbtO2 were collected simultaneously whenever a routine arterial blood gas was drawn. A PbtO2/PaO2 ratio was calculated for each blood gas and plotted over time for each patient. All patients were managed according to a standardized clinical protocol. A mixed effects model was used to account for repeated measurements in the same patient.

RESULTS

A total of 1006 data points were collected. The lowest mean PaO2 observed to maintain PbtO2 above the ischemic threshold was 94 mm Hg. Only PaO2 and cerebral perfusion pressure were predictive of PbtO2 in multivariate analysis. The PbtO2/PaO2 ratio was below 0.15 in 41.7% of all measures and normal PbtO2 values present despite an abnormal ratio in 27.1% of measurements.

CONCLUSIONS

The authors’ results suggest that the minimal PaO2 target to ensure adequate cerebral oxygenation during the first few days after TBI should be higher than that suggested in the Brain Trauma Foundation guidelines. The use of a PbtO2/PaO2 ratio (BOx ratio) may be clinically useful and identifies abnormal O2 delivery mechanisms (cerebral blood flow, diffusion, and cerebral metabolic rate of oxygen) despite normal PbtO2.

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Aladine A. Elsamadicy, David T. Lubkin, Amanda R. Sergesketter, Syed M. Adil, Lefko T. Charalambous, Nicolas Drysdale, Theresa Williamson, Joaquin Camara-Quintana, Muhammad M. Abd-El-Barr, C. Rory Goodwin, and Isaac O. Karikari

OBJECTIVE

In the United States, healthcare expenditures have been soaring at a concerning rate. There has been an excessive use of postoperative radiographs after spine surgery and this has been a target for hospitals to reduce unnecessary costs. However, there are only limited data identifying the rate of instrumentation changes on radiographs after complex spine surgery involving ≥ 5-level fusions.

METHODS

The medical records of 136 adult (≥ 18 years old) patients with spine deformity undergoing elective, primary complex spinal fusion (≥ 5 levels) for deformity correction at a major academic institution between 2010 and 2015 were reviewed. Patient demographics, comorbidities, and intra- and postoperative complication rates were collected for each patient. The authors reviewed the first 5 subsequent postoperative and follow-up radiographs, and determined whether revision of surgery was performed within 5 years postoperatively. The primary outcome investigated in this study was the rate of hardware changes on follow-up radiographs.

RESULTS

The majority of patients were female, with a mean age of 53.8 ± 20.0 years and a body mass index of 27.3 ± 6.2 kg/m2 (parametric data are expressed as the mean ± SD). The median number of fusion levels was 9 (interquartile range 7–13), with a mean length of surgery of 327.8 ± 124.7 minutes and an estimated blood loss of 1312.1 ± 1269.2 ml. The mean length of hospital stay was 6.6 ± 3.9 days, with a 30-day readmission rate of 14.0%. Postoperative and follow-up change in stability on radiographs (days from operation) included: image 1 (4.6 ± 9.3 days) 0.0%; image 2 (51.7 ± 49.9 days) 3.0%; image 3 (142.1 ± 179.8 days) 5.6%; image 4 (277.3 ± 272.5 days) 11.3%; and image 5 (463.1 ± 525.9 days) 15.7%. The 3rd year after surgery had the highest rate of hardware revision (5.55%), followed by the 2nd year (4.68%), and the 1st year (4.54%).

CONCLUSIONS

This study suggests that the rate of instrumentation changes on radiographs increases over time, with no changes occurring at the first postoperative image. In an era of cost-conscious healthcare, fewer orders for early radiographs after complex spinal fusions (≥ 5 levels) may not impact patient care and can reduce the overall use of healthcare resources.

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Cyrus Elahi, Theresa Williamson, Charis A. Spears, Sarah Williams, Josephine Nambi Najjuma, Catherine A. Staton, João Ricardo Nickenig Vissoci, Anthony Fuller, David Kitya, and Michael M. Haglund

OBJECTIVE

Traumatic brain injury (TBI), a burgeoning global health concern, is one condition that could benefit from prognostic modeling. Risk stratification of TBI patients on presentation to a health facility can support the prudent use of limited resources. The CRASH (Corticosteroid Randomisation After Significant Head Injury) model is a well-established prognostic model developed to augment complex decision-making. The authors’ current study objective was to better understand in-hospital decision-making for TBI patients and determine whether data from the CRASH risk calculator influenced provider assessment of prognosis.

METHODS

The authors performed a choice experiment using a simulated TBI case. All participant doctors received the same case, which included a patient history, vitals, and physical examination findings. Half the participants also received the CRASH risk score. Participants were asked to estimate the patient prognosis and decide the best next treatment step. The authors recruited a convenience sample of 28 doctors involved in TBI care at both a regional and a national referral hospital in Uganda.

RESULTS

For the simulated case, the CRASH risk scores for 14-day mortality and an unfavorable outcome at 6 months were 51.4% (95% CI 42.8%, 59.8%) and 89.8% (95% CI 86.0%, 92.6%), respectively. Overall, participants were overoptimistic when estimating the patient prognosis. Risk estimates by doctors provided with the CRASH risk score were closer to that score than estimates made by doctors in the control group; this effect was more pronounced for inexperienced doctors. Surgery was selected as the best next step by 86% of respondents.

CONCLUSIONS

This study was a novel assessment of a TBI prognostic model’s influence on provider estimation of risk in a low-resource setting. Exposure to CRASH risk score data reduced overoptimistic prognostication by doctors, particularly among inexperienced providers.

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Krzysztof A. Bujarski, Fuyuki Hirashima, David W. Roberts, Barbara C. Jobst, Karen L. Gilbert, Robert M. Roth, Laura A. Flashman, Brenna C. McDonald, Andrew J. Saykin, Rod C. Scott, Eric Dinnerstein, Julie Preston, Peter D. Williamson, and Vijay M. Thadani

Object

Previous comparisons of standard temporal lobectomy (STL) and selective amygdalohippocampectomy (SelAH) have been limited by inadequate long-term follow-up, variable definitions of favorable outcome, and inadequate consideration of psychiatric comorbidities.

Methods

The authors performed a retrospective analysis of seizure, cognitive, and psychiatric outcomes in a noncontemporaneous cohort of 69 patients with unilateral refractory temporal lobe epilepsy and MRI evidence of mesial temporal sclerosis after either an STL or an SelAH and examined seizure, cognitive, and psychiatric outcomes.

Results

The mean duration of follow-up for STL was 9.7 years (range 1–18 years), and for trans–middle temporal gyrus SelAH (mtg-SelAH) it was 6.85 years (range 1–15 years). There was no significant difference in seizure outcome when “favorable” was defined as time to loss of Engel Class I or II status; better seizure outcome was seen in the STL group when “favorable” was defined as time to loss of Engel Class IA status (p = 0.034). Further analysis revealed a higher occurrence of seizures solely during attempted medication withdrawal in the mtg-SelAH group than in the STL group (p = 0.016). The authors found no significant difference in the effect of surgery type on any cognitive and most psychiatric variables. Standard temporal lobectomy was associated with significantly higher scores on assessment of postsurgical paranoia (p = 0.048).

Conclusions

Overall, few differences in seizure, cognitive, and psychiatric outcome were found between STL and mtg-SelAH on long-term follow-up. Longer exposure to medication side effects after mtg-SelAH may adversely affect quality of life but is unlikely to cause additional functional impairment. In patients with high levels of presurgical psychiatric disease, mtg-SelAH may be the preferred surgery type.