Keyhole Evacuation for moderate basal ganglia Hematoma superior than Craniotomy

Background: Spontaneous intracerebral hemorrhage (SICH) is the most devastate kind of stokes.For basal ganglia hematoma with volume ranged from 30 to 60 ml, different surgical procedures have been recommended by different neurosurgeons.This study aimed to compare the clinical outcomes and hospitalization cost between keyhole surgery and craniotomy for basal ganglia intracerebral hemorrhage. Methods: A retrospective analysis was performed on clinical data of 63 cases of keyhole procedure and 56 cases of craniotomy procedure. Hematoma evacuation rate, infection rate, re-bleeding, operation time, hospitalization cost and outcome were recorded. Results: The evacuation rate was similar in keyhole group and craniotomy group (P>0.05), and infection rate was lower in keyhole group compared to craniotomy group (P<0.05). Mean operation time and hospitalization cost were less in keyhole group than in craniotomy group (P<0.05). Mortality rate between two groups showed no signicant differences. The patients operated within 6h had better outcome than those operated between 6-24h (p<0.05). Conclusion: For patients with basal ganglia hematoma ranged from 30-60 ml, keyhole surgery is safe and feasible, and operation within 6 h can improve the prognosis of the patients.


Background
Spontaneous intracerebral hemorrhage (SICH) is the most devastate kind of stokes. It was estimated that SICH affects over 1 million people worldwide every year with a mortality rate of more than 50% [1,2]. Only 12-39% of the survivors could live independently after 6 months [3][4][5]. The most common cause of SICH is hypertension, and about 60% of SICHs occur at the basal ganglia region [6,7]. Currently, the treatment of hematomas within the basal ganglia continues to be a matter of debate among neurologists and neurosurgeons [7][8][9]. The hematoma with small volume (< 30 ml of supratentorial) can be treated with conservative therapies, while larger hematoma (> 30 ml of supratentorial) is often removed through surgery.
Previous studies showed that the removal of hematoma might reduce nervous tissue damage, possibly by relieving local ischemia and removing noxious chemicals [6][7][8]. However, different surgical procedures have been recommended by different neurosurgeons, such as craniotomy, endoscopy operation, stereotactic aspiration, and keyhole evacuation [8][9][10]. In this study, we present our series of cases of basal ganglia hematoma with volume ranged from 30 to 60 ml who underwent keyhole evacuation or traditional craniotomy, and compared the safety and effectiveness of keyhole surgery with traditional craniotomy.

Ethical permission
This study was approved by Institute Ethics Committee and all patients signed written informed consent.

Patients
Patients enrolled in this study met the following inclusion criteria: 1) Aged 35-70 years; 2) computed tomography CT con rmed basal ganglia hemorrhage; 3) Hematoma volume between 30 to 60 ml; 4) Surgery performed within 24 hours from the onset of clinical symptoms. Patients were excluded if they had tumor bleeding, posttraumatic intracerebral hematomas, arteriovenous hemorrhage or aneurysmal, bleeding caused by uremia, liver cirrhosis, or anticoagulation therapy.
The keyhole group consisted of 63 consecutive adult patients admitted between July 2017 and July 2019. Traditional craniotomy group consisted of 56 consecutive patients treated by craniotomy at our department between July 2017 and July 2019. Clinical characteristics of the patients were recorded.

Traditional craniotomy
An arch incision about 20 cm long was made at the frontal temporal region, and a bone window about 6×8 cm was made with milling cutter. After opening the dura, the hematoma cavity was entered via a transcortical channel through the middle temporal gyrus or inferior temporal gyrus approach with a cortex incision about 1 cm. After evacuation of hematoma, the dura was sutured and the bone ap was replaced to its position. Usually drainage tube was put in the hematoma cavity and kept draining for 3 days.

Keyhole operation
The procedure was performed as described previously [10][11][12]. Brie y, 4-cm skin longitudinal straight incision was made about 3 cm posterior and 3 cm superior the pterion dot area as shown in Fig. 1a. A bone ap 2.5 cm in diameter was drilled (Fig. 1c). Sylvian ssure was dissected using the microsurgical technique. Sylvian veins and arteries had always been protected during surgery. A small insular cortex incision about 1 cm was made parallel to sylvian ssure, and hematoma on putamen was exposed after splitting the insular cortex. Hematoma evacuation was performed using suction and hemostasis with bipolar cautery. Usually drainage tube was put in the hematoma cavity and kept draining for 3 days.

Measurements
Hematoma volume was estimated by the following equation: V=length×width×thickness/2. The length, width and thickness were measured on CT images. The hematoma evacuation rate (%) was de ned as (preoperative volume -postoperative volume)/(preoperative volume) ×100 %. Re-bleeding was identi ed as postoperative CT volume greater than preoperative volume. The primary endpoint was re-bleeding and surgical complications and/or death. Outcome variables included hematoma evacuation rate, mean Glasgow Coma Scale (GCS) score at day 3 after operation, and Glasgow Outcome Scale (GOS) score 3 months after operation.
Statistical analysis SPSS version 13.0 was applied for all statistical analyses. Statistical analysis was carried out using t test or χ 2 test. P<0.05 was considered signi cant.
Results 63 cases of keyhole group and 56 cases of craniotomy group were evaluated in this study. All patients had altered consciousness with or without local neurologic de cit. Their characteristics are summarized in Table 1. The male ratio was 71.4% and 60.7% and the mean age was 48.5 and 50.5 years in two groups, respectively. 42 cases in keyhole group and 34 cases in craniotomy group had surgery within 6 hours after symptom onset, respectively. The mean hematoma volume was 46.7 ml in keyhole group and 48.5 ml in craniotomy group, respectively. There were no signi cant differences in hematoma volume and age between these two groups.
The evacuation rate in keyhole group ranged from 60-99%, while the evacuation rate of craniotomy group was from 30-99%. The mean evacuation rate of two groups was 78.4% and 80.6%, respectively without signi cant difference (p = 0.325). There was no difference in GOS score between two groups 3 months after surgery (P = 0.156, Table 2). The median operation time was signi cantly shorter in Keyhole group than in craniotomy group (116.4 vs. 143.7 minutes, p = 0.001). Only one case died of intracerebral infection in craniotomy group, mortality rate was 0% in keyhole group and 3.57% in craniotomy group, without signi cant difference (P > 0.05). ICU stay of keyhole group ranged from 0 to 9 days with the mean of 3.3 days. ICU stay of craniotomy group ranged from 0 to 12 days with the mean of 4.5 days, with signi cant difference between two groups. There was signi cant difference in hospitalization costs between two groups (p = 0.001, Table 2).
Total 76 cases received surgery within 6 hours after symptom onset (42 cases in keyhole group and 34 cases in craniotomy group), among them 52 cases had good prognosis with GOS more than 3. In contrast, only 25 cases had good prognosis among all cases received surgery after 6 hours after symptom onset (Table 3). However, there was no signi cant difference in re-bleeding incidence between ultra-early group (within 6 hours) and early group (> 6 hours) (3.22% vs. 5.56%; P = 0.245, Table 3).

Discussion
In clinical practice, hematoma with small volume (< 10 ml) can be treated with conservative measures and functional exercises for rehabilitation [7,8]. On the other hand, for large hematoma more than 30 ml which could threaten life or cause neurological dysfunction, surgery is essential [9,14]. However, different groups have recommended different surgical procedures [3,7,10]. To moderate volume basal ganglion hematoma ranging from 30 to 60 ml, there are several surgical procedures available, such as endoscopy operation, craniotomy, stereotactic aspiration and keyhole evacuation [9]. In this study, we introduced keyhole operation for moderate basal ganglion hematoma, and compared the complications and outcome with craniotomy.
Craniotomy approach is a classical way for clearing intracerebral bleeding in basal ganglia and is widely used in clinical practice. However, craniotomy prolongs the operation and anesthesia time, and increases the risk of infection and epilepsy. Moreover, craniotomy increases the risk of damage to the speech center and the vein of Labbe, leading to increased chance of complications [9,15]. Keyhole operation transsylvian-transinsular was performed in this study for moderate basal ganglion hematoma, and avoided the above defects of craniotomy. A challenge for keyhole operation of moderate basal ganglion hematoma is hemostasis during operation [11,12]. The bone window of only 2.5 cm in diameter may limit hematoma cavity exposure and lead to hematoma re-bleeding postoperatively [12,13]. In our series, there was no signi cant difference in re-bleeding rate of between two groups, re-bleeding rate of keyhole group was 4.76% (9 of 63 patients), similar to craniotomy group (rebleeding rate was 3.57%, 4 of 56 patients). Poor control of hypertension post-operatively may cause re-bleeding. Therefore, blood pressure control postoperatively is very important. Importantly, we found that infection rate was lower in keyhole group compared to craniotomy group, and mean operation time and hospitalization cost were less in keyhole group than in craniotomy group. These results showed the advantages of keyhole over craniotomy. Moreover, the patients operated within 6 h after symptom onset had better outcome than those operated between 6-24 h, suggesting that early operation is important to improve the prognosis of the patients no matter which operation approach is taken.

Conclusions
Although this study has several limitations such as retrospective nature, small sample size and highly selected patients, our results suggest that keyhole surgery is safe and feasible for moderate basal ganglion hematoma. Further randomized controlled large scale studies are necessary to con rm the safety and e cacy of keyhole surgery.

Declarations
Ethics approval and consent to participate The research protocol was approved by the Research Ethics Committee of Chongqing Medical University, China.

Consent for publication
All the patients signed the Consent for publication, and allowed to public the images and therapy data in this article without commercial interest.

Availability of data and material
The data used and/or analyzed during the current study can be abtained from the corresponding author by email.

Competing interests
No.