Outcomes of Decompressive Hemicraniectomy for Spontaneous Intracerebral Hemorrhage: A Case-Control Study

Research Article

Austin Neurol & Neurosci. 2016; 1(1): 1003.

Outcomes of Decompressive Hemicraniectomy for Spontaneous Intracerebral Hemorrhage: A Case-Control Study

Shah SO1,2,3,4*, Rincon F1,2,3,4 and Bar B1,2,3,4

¹Departments of Neurology, Thomas Jefferson University, Philadelphia, PA USA

²Neurosurgery, Thomas Jefferson University, Philadelphia, PA USA

³Divisions of Critical Care and Neurotrauma, Thomas Jefferson University, Philadelphia, PA USA

4Cerebrovascular Diseases, Thomas Jefferson University, Philadelphia, PA USA

*Corresponding author: Syed Omar Shah, Department of Neurological Surgery, Thomas Jefferson University and Jefferson College of Medicine, Philadelphia

Received: October 22, 2015; Accepted: February 22, 2016; Published: February 24, 2016

Abstract

Introduction: Intracerebral hemorrhage (ICH) remains a devastating type of stroke. Besides blood pressure control, treatment options including surgery remain limited. Decompressive hemicraniectomy (DHC) in patients with spontaneous ICH may be considered as salvage therapy. The purpose of this study is to evaluate the role of DHC for the management of primary ICH associated with malignant cerebral edema and its effect on case-fatality and long-term functional outcome.

Methods: A matched case control study was conducted at Thomas Jefferson University. Patient records were reviewed for age, sex; Glasgow Coma Scale (GCS) and ICH score on admission, on discharge and at follow-up. For those patients that underwent DHC, the time to surgery was documented. Computed tomography scans were then reviewed at the time of admission, allowing calculation of ICH scores. Functional outcome was assessed over the phone using the Simplified Modified Rankin Scale Questionnaire (smRSq). We matched (1:1) our cases to controls (ICH without DHC) by age and ICH score. The primary outcome of interest was survival over time. Secondary outcomes were discharge GCS and long-term functional outcome measured by the Modified Rankin Scale (mRS).

Results: There were 17 patients with DHC who were matched (1:1). The mean time to DHC was 61.3 ± 101 hours. Median mRS at follow-up was similar in DHC group vs. controls (4, IQR 4-6 vs. 5, IQR 3-6, p = 0.7).In multivariable analysis, predictors of death overtime were ICH score > 2, and female gender. Predictors of survival was DHC but only in patients with ICH score > 2 (HR 0.83, 95% CI 0.7-0.9, p = 0.04 for interaction).

Conclusion: This case-control study suggests that patients with ICH associated with significant cerebral edema and an ICH score greater than 2 may potentially benefit from DHC. Further research in a larger patient population conducted prospectively is warranted to assess the potential benefit of DHC in ICH.

Keywords: Decompressive hemicraniectomy; Intracerebral hemorrhage; Stroke; Refractory intracranial pressure

Introduction

Morbidity and mortality from Intracerebral Hemorrhage (ICH) are important public health problems [1,2]. Hypertensive ICH accounts for 10%–20% of strokes in the United States. About 40-80% of ICH patients die within the first 30 days and half of all deaths occur within the first 48 hours [3]. Survivors usually require long-term health care [2]. To date, there is no effective therapy for the treatment of ICH and most importantly, mortality remains unchanged [4]. The 30-day mortality rate for patients with ICH volumes greater than 50–60 cc range from 81%-91%, and poor functional outcome rates of 96%–97% have been reported for those with ICH volumes greater than 40–45 cc [5-8].

Current guidelines developed from the American Heart Association and American Stroke Association (AHA/ASA) recommend initial therapy including: relief of intracranial pressure (External Ventricular Drainage (EVD)), blood pressure control, correction of coagulopathies, seizures control, fever prevention, glycemic control, and DVT prophylaxis [8]. Trials have been focused on hematoma evacuation alone, such as The International Surgical Trial in Intracerebral Hemorrhage (STICH) [9]. Hematoma evacuation in cerebellar hemorrhage with brainstem compression and/or hydrocephalus is strongly recommended [8]. Furthermore, lobar clots > 3cc and within 1 cm of the surface should also be considered for evacuation [8]. STICH-II study was recently published and its goal was to determine whether hematoma evacuation within 12 hours would improve outcome compared with medical management [10]. Despite showing non-significant results on the primary endpoint, early surgery did not increase the rate of death or disability at 6 months and suggested a small survival advantage for patients with ICH who do not have intraventricular hemorrhage. Preliminary results from the Minimally Invasive Surgery plus rt-TPA for Intracerebral Hemorrhage Evacuation (MISTIE-II) demonstrated efficacy in the treatment of ICH by using stereotactic evacuation plus intracavitary administration of rt-TPA [11]. Although the guidelines address surgical management, they do not discuss the utility of Decompressive Hemicraniectomy (DHC) for management of malignant cerebral edema secondary to ICH.

DHC is a surgical option to reduce ICP, increase cerebral compliance and increase cerebral blood perfusion when medical management becomes inadequate. Unfortunately, there have only been a few observational studies evaluating DHC for ICH, and these studies are divided regarding whether to also perform a hematoma evacuation along side with DHC [12-20].

The purpose of this study is to evaluate the role of DHC for the management of primary ICH associated with malignant cerebral edema and its effect on case-fatality and long-term functional outcome. We hypothesized that after adjustments for known predictors of poor outcome, DHC after ICH would be associated with improved in-hospital case-fatality and long-term functional outcome.

Methods

We conducted a matched case control study. This study was conducted with the approval of the IRB of Thomas Jefferson University Hospital. Admissions at our institution with a primary diagnosis of ICH (ICD-9-CM, 431) with and without DHC (ICD-9-CM, 01.2) were identified by querying of the hospital discharge database [3]. From January 2011 to November 2014, 17 consecutive patients with ICH underwent a DHC in our institution. Patients included were over the age of 18 with primary spontaneous ICH. Exclusion criteria included patients who had ICH secondary to infratentorial origin, AVM, secondary to bleeding into tumor or stroke, TBI, and coagulopathy. Patients who had a pre-morbid modified Rankin scale mRS greater than 2 were also excluded. A board certified vascular neurologist or neurointensivist internally validated the inclusion and exclusion criteria.

Patient records were reviewed for age, sex; Glasgow Coma Scale (GCS) and ICH score on admission, on discharge and at follow-up. For those patients that underwent DHC, the time to surgery was documented. The laterality of the hematoma along with location, hematoma volume, midline shift, and the presence of Intraventricular Hemorrhage (IVH) were recorded. Admission hematoma volumes were measured using a validated semi-automated method. Volumes were estimated on 5-mm-thin slices of admission and follow-up CT scans using Osirix 64 Bit 5.9 software (https://www.osirix-viewer. com). The software was used to generate a polygonal region of interest from a range of Hounsfield units of 40-100. Regions of interest on each axial cut were then manually checked and adjusted to include any missing hemorrhage. Subsequently, the software computed the volume of the polyhedron defined by the regions of interests in cubic centimeters using a Power Crust reconstruction filter.

Patients were also evaluated using the ICH score. The ICH score is a validated measure of ICH severity used in research and clinical trials in ICH [21,22]. The components of the ICH score are: age, GCS, hematoma volume (ml), location (infratentorial vs. supratentorial), and presence of Intraventricular Hemorrhage (IVH) [21].

We matched (1:1) our cases to controls (ICH without DHC) by age and ICH score. All patients received maximal medical therapy which included hyperosmolar treatment (Mannitol, 3% Saline), mechanical ventilation, glycemic control, blood pressure management and analgesic sedation as appropriately needed. Intracranial pressure (ICP) monitoring was not undertaken routinely.

The primary outcome of interest was survival over time. Secondary outcomes were discharge GCS and long-term functional outcome measured by the Modified Rankin Scale (mRS). Poor outcome was defined as mRS 5-6. The mRS is a validated ordinal scale of neurological function ranging from 0 or no deficit to 6 or death [23]. mRS outcomes were collected for ICH survivors using a structured and validated telephone questionnaire [24].

Surgical Approach

The decision to pursue DHC was based on the collective judgment of the treating neurointensivists, attending neurosurgeon, and patient/family preferences. The laterality of the hemorrhage did not impact decisions to proceed with a DHC. All patients received either a unilateral frontal or fronto-parietal-occipital craniectomy based on the localization of the hemorrhage. The minimum diameter opening for the bone in all cases was at least 12 cm. The durotomies were performed in a cruciate fashion. The decision to perform clot evacuation along with the DHC was left to the neurosurgeon. Overall 24% of patients received clot evacuation. Duraplasty was achieved with either bovine pericardium or DuraMatrix (Stryker, Kalamazoo, MI). All patients had a JP drain inserted and remained in for 1-2 days postoperatively.

Statistical Analyses

Continuous variables were assessed for normality using the Kolmogorov-Smirnov test and reported using accepted standards for parametric and nonparametric data as means and Standard Deviations (SD) or medians and Interquartile Ranges (IQRs). Categorical variables were reported as count and proportions in each group. Bivariate comparisons were made using the t-test or Mann- U-Whitney test for continuous variables and Χ² or Fisher’s exact test for categorical variables. Missing data from patient’s lost-to follow up (two patients in the DHC group and one in the control group) were treated by carrying forward the last known outcome of interest. To account for differences in time to follow-up, a multivariable analysis using parametric survival models were fitted with time to event as the dependent variable and censoring for the outcome of interest (death). The main co-variate of interest (case (DHC) status) and additional factors associated with mortality after ICH were included in the models. Parsimonious models were found by systematically removing the least significant factor and recalculating the model. Multiple survival distributions were compared and the AIC or likelihood ratio test allowed us to assess relative model goodness of fit. To this end, the Weibull distribution best fitted the data. Finally, we calculated the Hazard Ratios (HR) and their 95% CI and studied potential interactions between covariates of interest. Statistical analyses were conducted using JMP software version 11.0 (SAS, Cary NC). Our reporting of observational data conforms to the Strengthening the Reporting of Observational Studies in Epidemiology STROBE guidelines [25].

Results

Demographics, admission severity scores, and radiological characteristics are summarized in (Table 1). There were 17 patients with DHC who were matched 1:1 by age and ICH score to historical controls. The mean time to DHC was 61.3 ± 101 hours. CT findings demonstrated a statistically significant difference in median admission midline shift in patients undergoing DHC (8mm, Interquartile Range (IQR) (4-12mm) vs. 3mm, IQR (2-8mm), p = 0.05). Other radiological findings were similar between the two cohorts (Table 1). There were no patients who had a hemorrhage of infratentorial origin.