Management of unruptured intracranial aneurysm in Japan: a Markovian decision analysis with utility measurements based on the Glasgow Outcome Scale

Imaging versus Intervention in Managing Small Unruptured Intracranial Aneurysms: A Cost-Effectiveness Analysis

OBJECTIVE

Current guidelines recommend active surveillance with serial magnetic resonance angiography (MRA) for management of small, asymptomatic unruptured anterior circulation aneurysms (UIAs). We sought to determine the cost-effectiveness of active surveillance compared to immediate surgery.

METHODS

We developed a Markov cost-effectiveness model simulating patients with small (<7 mm) UIAs managed by active surveillance via MRA, immediate surgery, or watchful waiting. Inputs for the model were abstracted from the literature and used to construct a comprehensive model following persons from diagnosis to death. Outcomes were quality-adjusted life-years (QALYs), lifetime medical costs (2015 USD), and incremental cost-effectiveness ratios (ICERs). Cost-effectiveness, deterministic, and probabilistic sensitivity analyses were performed.

RESULTS

Immediate surgical treatment was the most cost-effective management strategy for small UIAs with ICER of USD 45,772 relative to active surveillance. Sensitivity analysis demonstrated immediate surgery was the preferred strategy, if rupture rate was >0.1%/year and if the diagnosis age was <70 years, while active surveillance was preferred if surgical complication risk was >11%. Probabilistic sensitivity analysis demonstrated that at a willingness-to-pay of USD 100,000/QALY, immediate surgical treatment was the most cost-effective strategy in 64% of iterations.

CONCLUSION

Immediate surgical treatment is a cost-effective strategy for initial management of small UIAs in patients <70 years of age. While more costly than MRA, surgical treatment increased QALY. The cost-effectiveness of immediate surgery is highly sensitive to diagnosis age, rupture rate, and surgical complication risk. Though there are a wide range of rupture rates and complications associated with treatment, this analysis supports the treatment of small, unruptured anterior circulation intracranial aneurysms in patients <70 years of age.

Worse Than Death: Survey of Public Perceptions of Disability Outcomes After Hypothetical Traumatic Brain Injury

OBJECTIVE

The aim of this study was to determine the health utility states of the most commonly used traumatic brain injury (TBI) clinical trial endpoint, the Extended Glasgow Outcome Scale (GOSE).

SUMMARY BACKGROUND DATA

Health utilities represent the strength of one's preferences under conditions of uncertainty. There are insufficient data to indicate how an individual would value levels of disability after a TBI.

METHODS

This was a cross-sectional web-based online convenience sampling adaptive survey. Using a standard gamble approach, participants evaluated their preferences for GOSE health states 1 year after a hypothetical TBI. The categorical GOSE was studied from vegetative state (GOSE2) to upper good recovery (GOSE8). Median (25th percentile, 75th percentile) health utility values for different GOSE states after TBI, ranging from -1 (worse than death) to 1 (full health), with 0 as reference (death).

RESULTS

Of 3508 eligible participants, 3235 (92.22%) completed the survey. Participants rated lower GOSE states as having lower utility, with some states rated as worse than death, though the relationship was nonlinear and intervals were unequal between health states. Over 75% of participants rated a vegetative state (GOSE2, absence of awareness and bedridden) and about 50% rated lower severe disability (GOSE3, housebound needing all-day assistance) as conditions worse than death.

CONCLUSIONS

In the largest investigation of public perceptions about post-TBI disability, we demonstrate unequally rated health states, with some states perceived as worse than death. Although limited by selection bias, these results may guide future comparative-effectiveness research and shared medical decision-making after neurologic injury.

Cost-Effectiveness of Craniotomy for Epidural Hematomas at a Major Government Hospital in Cambodia

BACKGROUND

Epidural hematoma (EDH) is a common and potentially deadly occurrence following a severe traumatic brain injury. Our aim was to determine whether craniotomy is cost-effective when indicated for the treatment of EDH when a trained neurosurgeon is available.

METHODS

A decision tree was used to model the cost-effectiveness of craniotomy available versus craniotomy unavailable for the management of traumatic EDH from a Cambodian societal and provider perspective. Costs and effectiveness parameters were obtained from patient data at a large government hospital in Cambodia. Outcomes were measured in quality-adjusted life years (QALYs). Incremental cost per QALY and budget impact were calculated for each intervention at a willingness-to-pay (WTP) threshold of $9787.80/QALY (3× GDP per capita PPP). The time horizon reflected full life span, and costs and QALYs were discounted at 3%. Sensitivity analysis was also conducted.

RESULTS

Compared to craniotomy unavailable for EDH ($945.80; 11.78 QALYs), craniotomy available came at a higher cost and greater effectiveness ($1520.73; 12.78 QALYs), resulting in an incremental cost-effectiveness ratio (ICER) of $574.93. One-way analysis demonstrated that craniotomy unavailable became more cost-effective than craniotomy available when the percent chance of having a GOS of 4 or 5 was 60% for patients with an EDH where craniotomy was indicated but not performed. Probabilistic sensitivity analysis revealed that craniotomy available was more cost-effective than conservative management in 84.4% of simulations at the WTP threshold.

CONCLUSIONS

Craniotomy is a cost-effective treatment for patients with a traumatic EDH who meet criteria for operation when trained neurosurgeons are available onsite.

Health State Preference Weights for the Glasgow Outcome Scale Following Traumatic Brain Injury: A Systematic Review and Mapping Study

BACKGROUND

Valid and relevant estimates of health state preference weights (HSPWs) for Glasgow Outcome Scale (GOS) categories are a key input of economic models evaluating treatments for traumatic brain injury (TBI).

OBJECTIVES

To characterize existing HSPW estimates, and model the EuroQol five-dimensional questionnaire (EQ-5D) from the GOS, to inform parameterization of future economic models.

METHODS

A systematic review of HSPWs for GOS categories following TBI was conducted using a highly sensitive search strategy implemented in an extensive range of information sources between 1975 and 2016. A cross-sectional mapping study of GOS health states onto the three-level EQ-5D UK tariff index values was also performed in patients with significant TBI (head region Abbreviated Injury Scale score ≥3) from the Victoria State Trauma Registry. A limited dependent variable mixture model was used to estimate the 12-month EQ-5D UK value set as a function of GOS category, age, and other explanatory variables.

RESULTS

Six unique HSPWs from five eligible studies were identified. All studies were at high risk of bias with limited applicability. The magnitude of HSPWs differed significantly between studies. Three class mixture models demonstrated excellent goodness of fit to the observed Victoria State Trauma Registry data. GOS category, age at injury, sex, comorbidity, and major extracranial injury all had significant independent effects on mean EQ-5D utility values.

CONCLUSIONS

The few available HSPWs for GOS categories are challenged by potential biases and restricted generalizability. Mixture models are presented to provide HSPWs for GOS categories consistent with the National Institute for Health and Care Excellence reference case.

Impact of pregnancy on the size of small cerebral aneurysm

OBJECTIVE

Because the management of cerebral aneurysms during pregnancy remains controversial, the objective of this study was to perform a retrospective review of pregnant women with cerebral aneurysms to determine whether pregnancy is a risk factor for aneurysm rupture.

METHODS

The change in size of aneurysms during pregnancy was examined by performing repeat magnetic resonance angiography in five pregnant women with cerebral aneurysms between 2005 and 2013. The outcome examined was development of subarachnoid hemorrhage.

RESULTS

Among the five pregnancies, there were eight cerebral aneurysms. Subarachnoid hemorrhage did not developed during any pregnancy. In four of the pregnancies, the cerebral aneurysms did not change in size during pregnancy, remaining 2-5 mm. Although in one pregnancy, the aneurysm increased from 6 to 7 mm during the third trimester, it returned to its original size in the postpartum period.

CONCLUSIONS

We suggest that if the cerebral aneurysm is small (≤ 5 mm), it is likely to remain unchanged despite the increase in circulating blood volume during pregnancy. Cerebral aneurysms greater than 5 mm but without blebs, irregular shape, high-risk location, or increased aspect ratio are also at low risk of rupture and are not likely to change during pregnancy.

The Head Injury Transportation Straight to Neurosurgery (HITS-NS) randomised trial: a feasibility study

BACKGROUND

Reconfiguration of trauma services, with direct transport of traumatic brain injury (TBI) patients to neuroscience centres (NCs), bypassing non-specialist acute hospitals (NSAHs), could potentially improve outcomes. However, delays in stabilisation of airway, breathing and circulation (ABC) and the difficulties in reliably identifying TBI at scene may make this practice deleterious compared with selective secondary transfer from nearest NSAH to NC. National Institute for Health and Care Excellence guidance and systematic reviews suggested equipoise and poor-quality evidence - with regard to 'early neurosurgery' in this cohort - which we sought to address.

METHODS

Pilot cluster randomised controlled trial of bypass to NC conducted in two ambulance services with the ambulance station (n = 74) as unit of cluster [Lancashire/Cumbria in the North West Ambulance Service (NWAS) and the North East Ambulance Service (NEAS)]. Adult patients with signs of isolated TBI [Glasgow Coma Scale (GCS) score of < 13 in NWAS, GCS score of < 14 in NEAS] and stable ABC, injured nearest to a NSAH were transported either to that hospital (control clusters) or bypassed to the nearest NC (intervention clusters).

PRIMARY OUTCOMES

recruitment rate, protocol compliance, selection bias as a result of non-compliance, accuracy of paramedic TBI identification (overtriage of study inclusion criteria) and pathway acceptability to patients, families and staff. 'Open-label' secondary outcomes: 30-day mortality, 6-month Extended Glasgow Outcome Scale (GOSE) and European Quality of Life-5 Dimensions.

RESULTS

Overall, 56 clusters recruited 293 (169 intervention, 124 control) patients in 12 months, demonstrating cluster randomised pre-hospital trials as viable for heath service evaluations. Overall compliance was 62%, but 90% was achieved in the control arm and when face-to-face paramedic training was possible. Non-compliance appeared to be driven by proximity of the nearest hospital and perceptions of injury severity and so occurred more frequently in the intervention arm, in which the perceived time to the NC was greater and severity of injury was lower. Fewer than 25% of recruited patients had TBI on computed tomography scan (n = 70), with 7% (n = 20) requiring neurosurgery (craniotomy, craniectomy or intracranial pressure monitoring) but a further 18 requiring admission to an intensive care unit. An intention-to-treat analysis revealed the two trial arms to be equivalent in terms of age, GCS and severity of injury. No significant 30-day mortality differences were found (8.8% vs. 9.1/%; p > 0.05) in the 273 (159/113) patients with data available. There were no apparent differences in staff and patient preferences for either pathway, with satisfaction high with both. Very low responses to invitations to consent for follow-up in the large number of mild head injury-enrolled patients meant that only 20% of patients had 6-month outcomes. The trial-based economic evaluation could not focus on early neurosurgery because of these low numbers but instead investigated the comparative cost-effectiveness of bypass compared with selective secondary transfer for eligible patients at the scene of injury.

CONCLUSIONS

Current NHS England practice of bypassing patients with suspected TBI to neuroscience centres gives overtriage ratios of 13 : 1 for neurosurgery and 4 : 1 for TBI. This important finding makes studying the impact of bypass to facilitate early neurosurgery not plausible using this study design. Future research should explore an efficient comparative effectiveness design for evaluating 'early neurosurgery through bypass' and address the challenge of reliable TBI diagnosis at the scene of injury.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN68087745.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 1. See the NIHR Journals Library website for further project information.

Methods to place a value on additional evidence are illustrated using a case study of corticosteroids after traumatic brain injury

OBJECTIVES

To establish whether evidence about the effectiveness of a health care intervention is sufficient to justify the use of the intervention in practice and show how value of information (VOI) analysis can be used to place a value on the need for additional evidence and inform research prioritization decisions.

STUDY DESIGN AND SETTING

Meta-analysis provides an estimate of the effect of an intervention with uncertainty. VOI analysis determines the adverse health consequences of not resolving this uncertainty. A case study examining the evidence before the high profile trial of Corticosteroid Randomisation After Significant Head injury (CRASH) shows the consequences on patient outcomes if this trial had not been successfully funded.

RESULTS

The consequences of uncertainty before CRASH were high at 40 deaths and 1,067 years of full health per annum. VOI analysis indicates that CRASH was worthwhile and the UK National Health Service would have had to spend an additional £205 million elsewhere to generate health benefits similar to CRASH.

CONCLUSIONS

VOI analysis can be integrated with the results of meta-analysis to help inform whether a particular research proposal is potentially worthwhile and whether it should be prioritized over other research topics that could be commissioned with the same resources.

Economic Evaluations in the Diagnosis and Management of Traumatic Brain Injury: A Systematic Review and Analysis of Quality

BACKGROUND

Economic evaluations provide a unique opportunity to identify the optimal strategies for the diagnosis and management of traumatic brain injury (TBI), for which uncertainty is common and the economic burden is substantial.

OBJECTIVE

The objective of this study was to systematically review and examine the quality of contemporary economic evaluations in the diagnosis and management of TBI.

METHODS

Two reviewers independently searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, Health Technology Assessment Database, EconLit, and the Tufts CEA Registry for comparative economic evaluations published from 2000 onward (last updated on August 30, 2013). Data on methods, results, and quality were abstracted in duplicate. The results were summarized quantitatively and qualitatively.

RESULTS

Of 3539 citations, 24 economic evaluations met our inclusion criteria. Nine were cost-utility, five were cost-effectiveness, three were cost-minimization, and seven were cost-consequences analyses. Only six studies were of high quality. Current evidence from high-quality studies suggests the economic attractiveness of the following strategies: a low medical threshold for computed tomography (CT) scanning of asymptomatic infants with possible inflicted TBI, selective CT scanning of adults with mild TBI as per the Canadian CT Head Rule, management of severe TBI according to the Brain Trauma Foundation guidelines, management of TBI in dedicated neurocritical care units, and early transfer of patients with TBI with nonsurgical lesions to neuroscience centers.

CONCLUSIONS

Threshold-guided CT scanning, adherence to Brain Trauma Foundation guidelines, and care for patients with TBI, including those with nonsurgical lesions, in specialized settings appear to be economically attractive strategies.

Optimal approach to circumferential decompression and reconstruction for thoracic spine metastatic disease

BACKGROUND

Circumferential decompression has been demonstrated to be the first-line therapy for patients with metastatic tumors in the thoracic spine requiring surgical intervention. However, there is significant debate regarding whether these tumors are best accessed anteriorly utilizing a thoracotomy or posteriorly. We used decision analysis to determine which approach yields greater health-related quality of life (QOL).

METHODS

We searched Medline, Embase, and the Cochrane Library for relevant articles published between 1990 and 2011 on anterior and posterior approaches to metastatic disease in the thoracic spine. QOL values for major treatment outcomes were determined using the existing literature. Separate models were created for ambulatory and nonambulatory patients. A Monte Carlo simulation and sensitivity analyses were used to determine which treatment strategy resulted in the highest QOL.

RESULTS

For ambulatory patients, an anterior approach resulted in a slightly higher QOL, and for nonambulatory patients, a posterior approach was favored, but these differences were not statistically significant.

CONCLUSIONS

Using a decision-analytic model, we found no significant difference in QOL resulting from anterior versus posterior approaches to metastatic lesions in the thoracic spine. Decisions should instead be based on surgeon comfort, tumor characteristics, anatomy of the lesion, patient-related factors, and goals of the operation.

Comparative effectiveness of treatment options for pediatric craniopharyngiomas

OBJECT

No clear treatment guidelines for pediatric craniopharyngiomas exist. The authors developed a decision analytical model to evaluate outcomes of 4 surgical approaches for craniopharyngiomas in children, including attempted gross-total resection (GTR), planned subtotal removal plus radiotherapy, biopsy plus radiotherapy, and endoscopic resections of all kinds.

METHODS

Pooled data, including the authors' own experience, were used to create evidence tables, from which incidence, relative risks, and summary outcomes in quality-adjusted life years (QALYs) were calculated for the 4 management strategies.

RESULTS

Quality-adjusted life years at the 5-year follow-up were 2.3 ± 0.1 for attempted GTR, 2.9 ± 0.2 for planned subtotal removal plus radiotherapy, 3.9 ± 0.2 for biopsy plus radiotherapy, and 3.7 ± 0.2 for endoscopic resection (F = 17,150, p < 0.001). Similarly, QALYs at 10-year follow-up were 4.5 ± 0.2 for attempted GTR, 5.7 ± 0.5 for planned subtotal removal plus radiotherapy, and 7.8 ± 0.5 for biopsy plus radiotherapy (F = 6,173, p < 0.001). On post hoc pairwise comparisons, the differences between all pairs compared were also highly significant (p < 0.001). Since follow-up data at 10 years are lacking for endoscopic cases, this category was excluded from 10-year comparisons.

CONCLUSIONS

Biopsy with subsequent radiotherapy is the preferred approach with respect to improved overall quality of life. While endoscopic approaches also show promise in preserving quality of life at five-year follow-up, there are not sufficient data to draw conclusions about this comparison at 10 years.

The cost-effectiveness of diagnostic management strategies for children with minor head injury

AIM

To estimate the cost-effectiveness of diagnostic management strategies for children with minor head injury and identify an optimal strategy.

METHODS

A probabilistic decision analysis model was developed to estimate the costs and quality-adjusted life years (QALYs) accrued by each of six potential management strategies for minor head injury, including a theoretical 'zero option' strategy of discharging all patients home without investigation. The model took a lifetime horizon and the perspective of the National Health Service.

RESULTS

The optimal strategy was based on the Children's Head injury Algorithm for the prediction of Important Clinical Events (CHALICE) rule, although the costs and outcomes associated with each strategy were broadly similar.

CONCLUSIONS

Liberal use of CT scanning based on a high sensitivity decision rule is not only effective but also cost saving, with the CHALICE rule being the optimal strategy, although there is some uncertainty in the results. Incremental changes in the costs and QALYs are very small when all selective CT strategies are compared. The estimated cost of caring for patients with brain injury worsened by delayed treatment is very high compared with the cost of CT scanning. This analysis suggests that all hospitals receiving children with minor head injury should have unrestricted access to CT scanning for use in conjunction with evidence-based guidelines.

The cost-effectiveness of diagnostic management strategies for adults with minor head injury

STUDY OBJECTIVE

To estimate the cost-effectiveness of diagnostic management strategies for adults with minor head injury.

METHODS

A mathematical model was constructed to evaluate the incremental costs and effectiveness (Quality Adjusted Life years Gained, QALYs) of ten diagnostic management strategies for adults with minor head injuries. Secondary analyses were undertaken to determine the cost-effectiveness of hospital admission compared to discharge home and to explore the cost-effectiveness of strategies when no responsible adult was available to observe the patient after discharge.

RESULTS

The apparent optimal strategy was based on the high and medium risk Canadian CT Head Rule (CCHRhm), although the costs and outcomes associated with each strategy were broadly similar. Hospital admission for patients with non-neurosurgical injury on CT dominated discharge home, whilst hospital admission for clinically normal patients with a normal CT was not cost-effective compared to discharge home with or without a responsible adult at £39 and £2.5 million per QALY, respectively. A selective CT strategy with discharge home if the CT scan was normal remained optimal compared to not investigating or CT scanning all patients when there was no responsible adult available to observe them after discharge.

CONCLUSION

Our economic analysis confirms that the recent extension of access to CT scanning for minor head injury is appropriate. Liberal use of CT scanning based on a high sensitivity decision rule is not only effective but also cost-saving. The cost of CT scanning is very small compared to the estimated cost of caring for patients with brain injury worsened by delayed treatment. It is recommended therefore that all hospitals receiving patients with minor head injury should have unrestricted access to CT scanning for use in conjunction with evidence based guidelines. Provisionally the CCHRhm decision rule appears to be the best strategy although there is considerable uncertainty around the optimal decision rule. However, the CCHRhm rule appears to be the most widely validated and it therefore seems appropriate to conclude that the CCHRhm rule has the best evidence to support its use.

Comparative effectiveness in neurosurgery: what it means, how it is measured, and why it matters

Comparative effectiveness research has recently been the subject of intense discussion. With congressional support, there has been increasing funding and publication of studies using comparative effectiveness and related methodology. The neurosurgical field has been relatively slow to accept and embrace this approach. The author outlines the procedures and rationale of comparative effectiveness, illustrates how it applies to neurosurgical topics, and explains its importance.

Does the extended Glasgow Outcome Scale add value to the conventional Glasgow Outcome Scale?

The Glasgow Outcome Scale (GOS) is firmly established as the primary outcome measure for use in Phase III trials of interventions in traumatic brain injury (TBI). However, the GOS has been criticized for its lack of sensitivity to detect small but clinically relevant changes in outcome. The Glasgow Outcome Scale-Extended (GOSE) potentially addresses this criticism, and in this study we estimate the efficiency gain associated with using the GOSE in place of the GOS in ordinal analysis of 6-month outcome. The study uses both simulation and the reanalysis of existing data from two completed TBI studies, one an observational cohort study and the other a randomized controlled trial. As expected, the results show that using an ordinal technique to analyze the GOS gives a substantial gain in efficiency relative to the conventional analysis, which collapses the GOS onto a binary scale (favorable versus unfavorable outcome). We also found that using the GOSE gave a modest but consistent increase in efficiency relative to the GOS in both studies, corresponding to a reduction in the required sample size of the order of 3-5%. We recommend that the GOSE be used in place of the GOS as the primary outcome measure in trials of TBI, with an appropriate ordinal approach being taken to the statistical analysis.

Is aggressive treatment of traumatic brain injury cost-effective?

OBJECT

The object of this study was to determine whether aggressive treatment of severe traumatic brain injury (TBI), including invasive intracranial monitoring and decompressive craniectomy, is cost-effective.

METHODS

A decision-analytical model was created to compare costs, outcomes, and cost-effectiveness of 3 strategies for treating a patient with severe TBI. The aggressive-care approach is compared with "routine care," in which Brain Trauma Foundation guidelines are not followed. A "comfort care" category, in which a single day in the ICU is followed by routine floor care, is included for comparison only. Probabilities of each treatment resulting in various Glasgow Outcome Scale (GOS) scores were obtained from the literature. The GOS scores were converted to quality-adjusted life years (QALYs), based on expected longevity and calculated quality of life associated with each GOS category. Estimated direct (acute and long-term medical care) and indirect (loss of productivity) costs were calculated from the perspective of society. Sensitivity analyses employed a 2D Monte Carlo simulation of 1000 trials, each with 1000 patients. The model was also used to estimate these values for patients 40, 60, and 80 years of age.

RESULTS

For the average 20-year-old, aggressive care yields 11.7 (± 1.6 [SD]) QALYs, compared with routine care (10.0 ± 1.5 QALYs). This difference is highly significant (p < 0.0001). Although the differences in effectiveness between the 2 strategies diminish with advancing age, aggressive care remains significantly better at all ages. When all costs are considered, aggressive care is also significantly less costly than routine care ($1,264,000 ± $118,000 vs $1,361,000 ± $107,000) for the average 20-year-old. Aggressive care remains significantly less costly until age 80, at which age it costs more than routine care. However, even in the 80-year-old, aggressive care is likely the more cost-effective approach. Comfort care is associated with poorer outcomes at all ages and with higher costs for all groups except 80-year-olds.

CONCLUSIONS

When all the costs of severe TBI are considered, aggressive treatment is a cost-effective option, even for older patients. Comfort care for severe TBI is associated with poor outcomes and high costs, and should be reserved for situations in which aggressive approaches have failed or testing suggests such treatment is futile.

Cost-effectiveness of decompressive craniectomy as a lifesaving rescue procedure for patients with severe traumatic brain injury

BACKGROUND

Decompressive craniectomy has been traditionally used as a lifesaving rescue procedure for patients with refractory intracranial hypertension after severe traumatic brain injury (TBI), but its cost-effectiveness remains uncertain.

METHODS

Using data on length of stay in hospital, rehabilitation facility, procedural costs, and Glasgow Outcome Scale (GOS) up to 18 months after surgery, the average total hospital costs per life-year and quality-adjusted life-year (QALY) were calculated for patients who had decompressive craniectomy for TBI between 2004 and 2010 in Western Australia. The Corticosteroid Randomisation After Significant Head Injury prediction model was used to quantify the severity of TBI.

RESULTS

Of the 168 patients who had 18-month follow-up data available after the procedure, 70 (42%) achieved a good outcome (GOS-5), 27 (16%) had moderate disability (GOS-4), 34 (20%) had severe disability (GOS-3), 5 (3%) were in vegetative state (GOS-2), and 32 (19%) died (GOS-1). The hospital costs increased with the severity of TBI and peaked when the predicted risk of an unfavorable outcome was about 80%. The average cost per life-year gained (US$671,000 per life-year) and QALY (US$682,000 per QALY) increased substantially and became much more than the usual acceptable cost-effective limit (US$100,000 per QALY) when the predicted risk of an unfavorable outcome was >80%. Changing different underlying assumptions of the analysis did not change the results significantly.

CONCLUSIONS

Severity of TBI had an important effect on cost-effectiveness of decompressive craniectomy. As a lifesaving procedure, decompressive craniectomy was not cost-effective for patients with extremely severe TBI.

Decompressive hemicraniectomy for pediatric traumatic brain injury: long-term outcome based on quality of life

AIMS

The impact of decompressive hemicraniectomy (DCH) on the overall outcome of pediatric brain injury patients has not been fully determined. In this paper, the authors performed a systematic review of patient outcome based on quality of life following DCH in a pediatric population.

METHODS

We describe our experience with decompressive craniectomy in pediatric patients and perform a literature review and pooled outcomes analysis to supplement these findings. A total of 13 children underwent DCH for intractable intracranial pressure in our institution from 2000 to 2008. Follow-up was available in 11 patients with 1 death (9%) and 7 survivors (70%) obtaining a favorable outcome (Glasgow Outcome Scale, GOS, scores = 4-5).

RESULTS

A literature review to determine the usefulness of DCH identified 17 articles that, when combined with our series, resulted in 186 pediatric DCH cases. Pooled outcomes found 42 deaths and 112 patients who had favorable outcomes at 6 months. The average 6-month mortality was 21.1%, and the pooled mean quality of life among survivors 0.75 (0.68-0.82), midway between moderate disability and good outcome.

CONCLUSIONS

Based on our findings, DCH results in a majority of pediatric patients having a good outcome based on the GOS score.

Quality of life after hemicraniectomy for traumatic brain injury in adults

Decompressive hemicraniectomy is well accepted for the surgical treatment of intractable intracranial hypertension in cases in which medical management fails. Although it is performed as a life-saving procedure when death is imminent from intracranial hypertension, little is known about the functional outcomes for these patients on long-term follow-up. In this study, the authors performed a systematic review of the literature to examine neurological outcome after hemicraniectomy. A literature search revealed 29 studies that reported outcomes using GOS scores. The GOS scores were transformed to utility values for quality of life using a conversion method based on decision analysis modeling. Based on the literature, 1422 cases were analyzed. The average 6-month-postoperative mortality rate was 28.2%. The mean QOL value among survivors was 0.592, which corresponds roughly to a GOS score of 4. Although more studies are needed for validation of long-term neurological outcome after hemicraniectomy, the assumption that most patients remain in a vegetative state after this intervention is clearly incorrect.

Model-based cost-effectiveness analyses for the treatment of acute stroke events: a review and summary of challenges

OBJECTIVE

To summarize the methodological approaches used in published decision-analytic models evaluating interventions for acute stroke treatment, to highlight key components of decision-analytic models of stroke treatment, and to discuss challenges for developing stroke decision models.

METHODS

A review of the published literature was performed using Medline, to identify studies involving mathematical decision models to evaluate interventions for acute stroke treatment. Articles were analyzed to determine key components of a stroke model and to note areas in which data are lacking.

RESULTS

We identified 13 published models of acute stroke treatment. These models typically possessed a short-term treatment module and a long-term post-treatment module. The following aspects of economic modeling were found to be relevant for developing a stroke model: modeling approach and health state; health state transition probabilities; estimation of short-term, long-term, and indirect costs; health state utilities; poststroke mortality; time horizon; model validation; and estimation of parameter uncertainty.

CONCLUSIONS

Data gaps have limited the development of economic models in stroke to date. In order to more accurately assess the long-term incremental impact of a new treatment of stroke, future research is needed to address these data gaps. We recommend that the complexity of models for examining the cost-effectiveness of an acute stroke treatment be kept to a minimum such that it can incorporate the currently available data without making a large number of assumptions around the data.

Cost-effectiveness of treatment of unruptured intracranial aneurysms in patients with a history of subarachnoid hemorrhage

RATIONALE AND OBJECTIVES

The study goal was to evaluate the cost-effectiveness of surgery and endovascular treatment of unruptured intracranial aneurysms in patients with a history of subarachnoid hemorrhage from a previous aneurysm, incorporating the results of the prospective International Study of Unruptured Intracranial Aneurysms.

MATERIALS AND METHODS

Using a Markov model, we performed a decision and cost-effectiveness analysis comparing surgery or endovascular treatment with no treatment. Twelve clinical scenarios were defined based on aneurysm size and location. Probabilistic sensitivity analyses were performed for 50- and 40-year-old cohorts. Treatment was considered to be cost-effective at an incremental cost-effectiveness ratio less than $100,000 per quality-adjusted life-year.

RESULTS

In 50-year-old patients, no treatment was the most cost-effective strategy for aneurysms located in the cavernous carotid artery. For aneurysms less than 7 mm located in the anterior circulation, no treatment was the most cost-effective strategy. Endovascular treatment was the most cost-effective option for 7- to 24-mm aneurysms, whereas surgery was the most cost-effective option for aneurysms of 25 mm or larger. For aneurysms less than 7 mm and located in the posterior circulation, endovascular treatment was the most cost-effective option, whereas surgery was the most cost-effective option for 7- to 12-mm aneurysms. No treatment was the most cost-effective strategy for aneurysms of 13 mm or larger.

CONCLUSION

For 50-year-old patients with a history of aneurysmal subarachnoid hemorrhage, treatment of unruptured aneurysms that are located in the cavernous carotid artery, or small (<7 mm) and located in the anterior circulation, or large (>or=13 mm) and located in the posterior circulation is ineffective or not cost-effective.

Treatment of unruptured intracranial aneurysms: decision and cost-effectiveness analysis

PURPOSE

To prospectively perform a decision and cost-effectiveness analysis of surgical and endovascular treatments of unruptured intracranial aneurysms, with incorporation of the results of the prospective International Study of Unruptured Intracranial Aneurysms.

MATERIALS AND METHODS

With use of a Markov model, a decision and cost-effectiveness analysis was performed for comparison of surgical or endovascular treatment with no treatment. Twelve clinical scenarios were defined on the basis of aneurysm size and location. Probabilistic sensitivity analyses were performed for 50- and 40-year-old patient cohorts. Treatment was considered to be cost-effective at an incremental cost-effectiveness ratio less than $100,000 per quality-adjusted life-year.

RESULTS

In 50-year-old patients, no treatment was the most cost-effective strategy for aneurysms located in the cavernous carotid artery. For aneurysms smaller than 7 mm located in the anterior circulation, no treatment was the most cost-effective strategy. Endovascular treatment was the most cost-effective option for 7-24-mm aneurysms, whereas surgical treatment was the most cost-effective option for aneurysms 25 mm or larger. For aneurysms smaller than 7 mm or 25 mm or larger located in the posterior circulation, no treatment was the most cost-effective strategy. Surgical treatment was the most cost-effective option for 7-12-mm aneurysms, whereas endovascular treatment was the most cost-effective option for 13-24-mm aneurysms.

CONCLUSION

For 50-year-old patients, treatment of aneurysms that are small (<7 mm), that are located in the cavernous carotid artery, or that are large (>or=25 mm) and located in the posterior circulation is ineffective or not cost-effective.

Anévrismes intracrâniens non rompus : que proposer ?

Intracranial unruptured aneurysm (ICUA) has become a common condition for patient consultation. The mortality rate after fissuration is estimated to be between 52% and 85.7%. The final therapeutic decision results from a balance between the risk of rupture and risks related to the aneurysmal exclusion. Analysis of the risk of rupture risk enables a classification of risk factors. Depending on the circumstances of diagnosis, we considered the ICUA at high risk of rupture for incidental ICUA larger than 7 mm and in the event of associated aneurysms. Classifying by morphologic features, high-risk ICUA were located in the vertebrobasilar system (RR: 4.4; 95%CI: 2.7-6.8), those with a size between 7 and 12 mm (RR: 3.3; 95%CO: 1.3-8.2), larger than 12 mm (RR: 17; 95%CI: 8-36.1), those that were multilobular or a larger size and those ones with a index P/L superior to 3.4 (risk x20). Familial ICUA would expose to a major rupture risk (2 to 7 times sporadic ICUA). Some systemic factors were related to ICUA rupture: arterial hypertension (RR: 1.46; 95%CI: 1.01-2.11) and smoking addiction (RR: 3.04; 95%CI: 1.21-7.66). After microsurgical exclusion, the morbidity and mortality rates were 10% and 2% respectively. Some microsurgical morbidity factors were identified: age (32%>65 years), size (14%>15 mm), vertebrobasilar location and temporary occlusion. The rupture incidence after microsurgical exclusion was estimated 0.26%/year. After endovascular exclusion, the morbidity and mortality rates were 8% and 1% respectively. The complete exclusion rate varied between 47% and 67%. The rupture risk was estimated at 0.9%/year. Treatment recommendations were classified into 3 categories.

Prophylaxis for Deep Venous Thrombosis in Craniotomy Patients: A Decision Analysis

OBJECTIVE:

We sought to determine the most efficient perioperative prophylactic strategy for deep venous thrombosis (DVT) in craniotomy patients by use of a decision analysis model.

METHODS:

We conducted a structured review of the relevant literature and compiled the reported incidences of DVT, pulmonary embolism, and postoperative intracranial hemorrhage (ICH) in craniotomy patients. We also obtained from the literature estimates of the likelihood and the impact of various outcomes of these complications. Data from 810 craniotomies performed at our own institution were also examined. The decision analytic model was then used to compare the effectiveness of pneumatic compression boots with pneumatic compression boots combined with either unfractionated or low-molecular-weight heparin. The model dealt with variability by using both sensitivity analysis and Monte Carlo simulation.

RESULTS:

As expected, the addition of heparin lowered the incidence of both DVT and pulmonary embolism, but at the cost of increasing ICH. Because the deleterious effects of ICH were so much greater than the benefits from heparinization, overall outcomes were best with mechanical prophylaxis alone. This was especially true for low-molecular-weight heparin, which is associated with a relatively high risk of ICH. Our own institutional data support the findings in the literature. Although the differences are modest, they reach statistical significance in the case of low-molecular-weight heparin.

CONCLUSION:

Using decision analytic modeling, we have shown that mechanical prophylaxis yields outcomes in craniotomy patients superior to those of either unfractionated or low-molecular-weight heparin.

A probabilistic and interactive decision-analysis system for unruptured intracranial aneurysms

OBJECT

The goal in this study was to develop an interactive, probabilistic decision-analysis system for clinical use in the decision to treat or observe unruptured intracranial aneurysms. Further goals were to enable users of the system to adapt decision-analysis methods to individual patients and to provide a tool for interactive sensitivity analysis.

METHODS

A computer program was designed to model the outcomes of treatment and observation of unruptured aneurysms. The user supplies probabilistic estimates of key parameters relating to a specific patient and nominates discount rate and quality of life adjustments. The program uses Monte Carlo discrete-event simulation methods to derive probability estimates of the outcomes of treatment and observation. Results are expressed as summary statistics and graphs. Discounted quality-adjusted life years are graphed using survival methods. Hierarchical simulations are used to enable investigators to perform probabilistic sensitivity analysis for one or multiple parameters simultaneously. The results of sensitivity analysis are expressed in graphs and as the expected value of perfect information. The system can be distributed and updated using the Internet.

CONCLUSIONS

Further research is required into the benefits of clinical application of this system. Further research is also required into the optimum level of complexity of the model, into the user interface, and into how clinicians and patients are likely to interpret results. The system is easily adaptable to a range of medical decision analyses.

Unruptured intracranial aneurysms: benign curiosity or ticking bomb?

15 years ago, the treatment of incidentally discovered intracranial aneurysms was straightforward with a good evidence base behind it. When intracranial aneurysms were identified, people were referred to neurosurgeons who would offer surgical repair if the patient was in reasonable health and had a good life expectancy. Since that time, several studies have given contradictory evidence for what should be done with these lesions, and a new technique for the repair of aneurysms, endovascular coil embolisation, has been developed. Here we review the research and make several recommendations. First, incidentally discovered aneurysms in the anterior circulation less than 7 mm in size in people with no personal or family history of subarachnoid haemorrhage should be left untreated. Second, people with remaining life expectancy of less than 20 years or so (ie, those over age 60 years) should be informed that from a statistical point of view the benefits of treatment do not outweigh the risks. Third, in all other cases treatment with surgical clipping or coil embolisation should be advised. And finally, if surgical treatment is not feasible then medical hypotensive treatment may be a viable alternative.

Stroke: Effect of implementing an evaluation and treatment protocol compliant with NINDS recommendations

PURPOSE

To evaluate--relative to routine clinical practice--the potential cost-effectiveness of implementing a strategy compliant with National Institute of Neurological Disorders and Stroke (NINDS) recommendations for care of patients presenting with signs and symptoms of acute ischemic stroke.

MATERIALS AND METHODS

A discrete-event simulation model of the process of stroke care from symptom onset through administration of tissue plasminogen activator (tPA) was constructed. A literature review was performed to determine process times, performance of computed tomography (CT), health outcomes, and cost estimates. The following were compared: (a) a "base-case" strategy determined on the basis of findings in the literature and (b) a NINDS-compliant strategy (ie, evaluation by emergency physician in less than 10 minutes, interpretation of CT scans within 45 minutes, and administration of tPA within 1 hour after presentation). Strategies were compared with regard to cost and effectiveness. Sensitivity analyses were performed for all relevant cost, timing, and resource parameters. Outcomes of concern were quality-adjusted life years and number of patients treated within a 3-hour therapeutic window.

RESULTS

The NINDS-compliant strategy resulted in an average quality-adjusted life years value of 3.64, versus 3.63 for the base case, at an approximate cost of 434 US dollars per patient. The NINDS-compliant strategy increased the proportion of treatable patients from 1.4% to 3.7% and remained cost-effective for expenditures of up to 450 US dollars per patient. Assuming base-case parameters are used, increasing the number of CT scanners from two to eight raised the proportion of treatable patients to 1.5%. Increasing the number of available neurologists from four to eight raised the proportion to 1.44%. Reducing the time from stroke onset to emergency department arrival by 30 minutes raised the proportion to up to 7.7%.

CONCLUSION

Applying NINDS recommendations is potentially cost-effective, although reducing the time from stroke onset to emergency department arrival may be even more so.

Aneurysm observation versus intervention: a literature review

Aneurysmal subarachnoid hemorrhage (SAH) is a devastating illness that affects persons at the peaks of their lives. The 1990s witnessed rapid growth in noninvasive vascular imaging technologies, which allowed safe diagnosis of unruptured saccular intracranial aneurysms. Presently, it is unclear who will benefit from screening. Mass screening is neither feasible nor cost-effective. The current literature suggests that persons in a family with two or more relatives with a history of SAH are most likely to benefit from screening. Individuals with a history of SAH, with aneurysms greater than 10 mm in diameter or with symptomatic aneurysms are clearly at increased risk for SAH. These aneurysms should be treated, though the method of treatment remains open to question. Treatment of older patients or those with smaller aneurysms has been modeled by decision analysis, but has yet to be verified in a prospective clinical trial. Future directions for aneurysm management are explored.

Endovascular management of unruptured intracranial aneurysms: does outcome justify treatment?

OBJECTIVE

The appropriate management of unruptured intracranial aneurysms depends on a complete understanding of their natural history and on the risks and efficacy of treatment options. There is little current data on the risks of endovascular therapy for these aneurysms. The aim of this study was to assess outcome of endovascular treatment of unruptured intracranial aneurysms.

METHOD

A retrospective analysis was performed on all unruptured aneurysms treated by Guglielmi detachable (GD) coils at this institution from 1994 to 2000.

RESULTS

Seventy three unruptured aneurysms were treated in 62 patients. There were 52 female and 10 male patients, with a median age of 55.7 years. Clinical background was: subarachnoid haemorrhage due to rupture of an additional aneurysm (40), headache (4), third nerve palsy (four), familial (four), and incidental (10). There were 14 technical failures with no clinical sequelae. Four procedural complications occurred (5.5%, 95% confidence interval (95% CI) 0.3% to 10.9%). One patient had temporary clinical sequelae (1.4%, 95% CI 0% to 2.7%); 79% of treated aneurysms had stable occlusions at follow up, 10.5% showed improved occlusion grade, 10.5% showed some recurrence, and three patients have required retreatment. Follow up modified Glasgow outcome scores were grade 1, 71%; grade 2, 18%; grade 3, 3%; grade 4, 3%. There were no deaths or haemorrhages during the follow up period. Two patients died as a result of complications from subarachnoid haemorrhage.

CONCLUSION

The endovascular treatment of patients with unruptured aneurysms is safe with few clinical or procedural complications. Poor outcomes were only seen in those patients who presented with subarachnoid haemorrhage due to rupture of an aneurysm at another site.

Unruptured Intracranial Aneurysms: Appraisal of the Literature and Suggested Recommendations for Surgery, Using Evidence-based Medicine Criteria

OBJECTIVE

The literature on unruptured intracranial aneurysms is reviewed, and an attempt is made to stratify it according to the weight of the evidence. Recommendations for surgery are suggested, using evidence-based criteria.

METHODS

A MEDLINE search was performed for 1966 to 1999. The focus was restricted to surgical management rather than other types of management, such as endovascular treatments. Each article was classified as Class I, II, or III according to the weight of the evidence. Some articles, such as literature reviews and data analyses, did not fit this classification and were grouped separately. Recommendations are based on the evidence available.

RESULTS

Forty-five articles were reviewed. Thirteen articles contained information on the natural history, 19 contained data on the risks of surgery, and 2 contained information on both. In addition, 11 contained analyses of costs and benefits. None met the criteria for Class I evidence. Seven articles on the natural history and 7 on the risks of surgery met the criteria for Class II evidence, and 6 and 12, respectively, met those for Class III evidence. The remainder of the articles were analyses or review articles.

CONCLUSION

There is insufficient evidence to recommend a standard of management. As a therapeutic guideline, conservative treatment is recommended for small aneurysms (&lt;10 mm) and asymptomatic nongiant aneurysms in older people, whereas surgery is recommended for larger aneurysms in younger people and symptomatic aneurysms in fit patients. Other recommendations can be justified only as therapeutic options, using evidence-based criteria. Areas for future investigation are discussed.