The Ethics Committee of the Affiliated Hospital of Guizhou Medical University approved this retrospective study. The study was performed based on the WMA Declaration of Helsinki. Patients with ICH admitted to our hospital and underwent sMIS were included in our study. The recruitment period was from January 1, 2018 to June 30, 2019.
2.1 Study design and participants
2.1.1 Study design
A retrospective analysis was performed in the present study. The authors aimed to determine whether initial CT blend signs are associated with poor functional outcome of patients with ICH following sMIS. We collected data from patients with ICH by reviewing the medical records of the Affiliated Hospital of Guizhou Medical University. The recruitment period was from January 1, 2018 to June 30, 2019. The patients were diagnosed by a baseline CT scan within 1 hour of admission, and the surgery was performed within 24 hours after admission. The eligible patients with ICH were selected by the inclusion criteria below. All eligible patients were treated by sMIS and were assigned to two groups based on their haematoma features.
The inclusion criteria were as follows: (1) Patients (over 18 years old) with a history of hypertension or hypertension observed upon admission, and the symptoms and signs met the diagnostic criteria for ICH, which was confirmed by a non-enhanced CT scan. (2) Patients suffered from spontaneous ICH in the basal ganglia and thalamus. (3) Patients with the ICH volume between 30 ml and 50 ml. (4)Patients were candidates without contraindications for surgery. (4) Authorized representatives of the patients provided consent for the surgery.
The exclusion criteria were the same as previously published studies15. Patients with ICH located in the brainstem or with secondary ICH from haemorrhagic transformation from brain infarction were not included. Patient without an authorized representative consent to surgery were also excluded from the study.
From January 1, 2018 to June 30, 2019, a total of 710 patients with spontaneous ICH were admitted to the Affiliated Hospital of Guizhou Medical University. Among them, 318 patients received sMIS. Of the 318 patients that underwent sMIS, 25 patients left the hospital in one week without medical orders, and 21 patients with ICH located in the brainstem, another 30 patients with large volume (over 50 mL) ICH. These 76 patients were not included in the final analysis (Fig.1).
Based on the inclusion criteria, 242 sequential patients with spontaneous ICH were included in the present study. All the patients received a sMIS. The patients were assigned to the following groups based on their CT haematoma features. The blend sign group included 91 patients and the non-blend sign group (control group) included 151 patients with spontaneous ICH. The baseline clinical characteristics of patients were listed in Table 1. The blend sign group showed higher rate of hypertension history (P=0.004) and gender (male, P=0.027) over the control group. There were not statistic differences in age, hypertension, diabetes mellitus, smoking, and alcoholic drinking between the blend sign group and the control group.
2.2 Imaging analysis
The initial CT and follow-up CT scans (General Electric Medical Systems, Milwaukee,WI) were performed using standard clinical parameters with axial 3-mm-thick sections, current of 225 mA, window level of 39 and window width of 120. The images were obtained and stored for further evaluation. The ICH for each patient was located in the basal ganglia and thalamus. Two experienced experts (one neurosurgical and one neuroimaging experts) blinded to the clinical information of the patients served as reviewers and independently evaluated the shape features of the haematoma. The shape of the haematoma was assessed by visual inspection16. The blend sign was determined by the criteria proposed in previously published studies17. Discrepancies about the presence of the blend signs were settled by joint discussion between the readers.
Haematoma volumes were estimated based on CT using the ABC/2 formula (t=π/6×l×s×slice) 18. The criteria for identify the blend sign was the same as those reported in the literature15. The blend sign was composed of two parts with different densities on CT (Fig.2)
2.3 Treatment of patients
2.3.1 sMIS for ICH evacuation
The sMIS for the ICH evacuation was the same procedure that was used in our previously published studies19, 22, 23. In order to remove the influences of the surgical technical factors on the outcomes, the surgical procedures were performed by two experienced neurosurgeons. Briefly, a stereotactic instrument was fixed on the patient’s skull and a repeated CT scan was performed for each patient prior to surgery. After the repeating CT scan was performed, the patient was transferred to the operating room. Using the CT scan, the coordinates of the ICH was figured out and we punctured the skull by using a 3-mm-diameter needle (with a drill integrated into the needle guard) under the guidance of the stereotactic instrument. After the drill was replaced by a tip-blunt plastic-needle core, the LY-1-type puncture-needle set was inserted slightly into the haematoma. Following removal of the plastic-needle core, the liquid part of the haematoma was aspirated with a 10-ml syringe. The aspiration was stopped after first resistance was encountered, and the needle guard connected to a plastic tube was retained for several days for drainage. The patients were transferred to the intensive care unit after removing the location framework and stereotactic apparatus. Then, 50,000 units (diluted in 2 ml of normal saline) of urokinase were injected slowly every 8 hours into the residual haematoma area to dissolve the solid part of the haematoma. The needle system was closed for 2 hours before reopening to allow spontaneous drainage. The first postoperative follow-up CT scan was performed on following day after surgery and the second postoperative CT was performed on the third day after surgery. Some patients needed a third or even a fourth postoperative follow-up CT scan. If the patients showed neurological deterioration after surgery, a repeated CT scan was performed at any time.
All patients in our study received the same medical management based on the guidelines for the treatment of hypertensive ICH19. In addition, more comprehensive measures were also taken in all patients, including the prevention of deep-venous thrombosis (DVT), the control of temperature and blood glucose, nutritional support, and the prevention of other complications. The main measures for preventing DVT were to move slowly the paralysed limbs and to wear socks. No anticoagulants were used to prevent DVT during the hospital stay because they might induce haemorrhage.
2.4 Efficacy outcome
The primary efficacy outcomes were functional good outcome, defined as the proportion of patients who achieved a modified Ranking Scale (mRS) score of 0–3 in at discharge. The secondary outcomes included the National Institutes of Health Stroke Scale (NIHSS) scores, the Glasgow Coma Scale (GCS) scores and the ICH volume changes. The outcome was considered favourable if the mRS score was 0–3 points. In contrast, if the mRS score was >3 points, the outcome was considered poor4. The GCS and the NIHSS scores were assessed on admission and at one week and two weeks after surgery by experienced neurological experts. The mortality and complications were recorded during the hospital stay and were compared between the two groups.
2.5.2 Cardiopulmonary complications
Some patients suffered from life-threatening complications during their hospital stay. Severe cardiopulmonary complications mainly included severe pulmonary infection, respiratory failure, or heart failure. The cardiopulmonary complications included were those that occurred in their hospital stay. The exacerbation of chronic heart failure and respiratory failure, as well as community-acquired pneumonia, was not included.
2.6 Statistical analysis
On the basis of the assumption that 38% of patients with ICH would have a mRS score of 0–3 following sMIS4, we estimated that 180 patients would provide 95% statistical power at an α level of 0.05. The permissible error d was 0.1, and the design deficiency (deff) was 2. The sample size was calculated using the following formula:
A commercially available software package (SPSS, Version 22.0) was used to perform the statistical analyses. Categorical data are shown as proportions, and continuous variables are presented as`x±S. Demographic, clinical, and radiological characteristics were compared between patients with shape-regular or shape-irregular ICH using Student’s t tests (for normal distribution) or a non-parametric test (if the data were not normally distributed). A difference in the GCS and NIHSS scores between different time points was analysed by the method of repeated measures. A p value less than 0.05 was considered to indicate a statistically significant difference. The independent association between the initial CT blend sign and the outcome of patients after sMIS was evaluated using multivariable logistic regression. The interobserver reliability of CT blend sign was assessed by calculating the κ values. The κ values were categorized as reported in the literature15. When the κ value is equal to 1, it indicates total agreement between the observers.