The Usefulness of the 3.1-mm-diameter 4K Rigid Endoscope for Intracerebral Hematoma Evacuation

Abstract

The indication for surgical intervention in spontaneous intracerebral hemorrhage remains controversial. Although many clinical trials have failed to demonstrate its efficacy over medical treatment, less invasive endoscopic treatment is expected to demonstrate its superiority. A novel endoscopic system for hematoma removal consisting of a 3.1-mm-diameter 4K high-resolution rigid endoscope was used.

The system was used in eight cases of spontaneous intracerebral hemorrhage. It provided improved maneuverability of the surgical instrument while maintaining satisfactory image quality. The surgical goal was achieved in all cases without any complications, including perioperative rebleeding.

Endoscopic hematoma removal using the 3.1 mm high-resolution endoscope is an alternative minimally invasive approach to spontaneous intracerebral hemorrhage with improved reliability.

Introduction

Spontaneous intracerebral hemorrhage is a common disease that significantly impacts subsequent activities of daily living. Although several randomized trials have failed to demonstrate the efficacy of craniotomy over medical therapy,^1,2) there is a growing hope that the less invasive technique of endoscopic hematoma removal will prove effective. However, the endoscopes and sheath diameters as well as the surgical instruments used differ between different centers.

The outer diameters of the rigid endoscopes commonly used for hematoma removal in intracerebral hemorrhage are 2.7 mm and 4 mm, and the outer diameter of the sheaths is often around 10 mm.^3,4) A narrower endoscope reduces interference with surgical instruments and facilitates manipulation within the sheath, but at the same time, the viewing angle is narrower and the brightness is lower, which decreases the visibility of the surgical field. Considering these advantages and disadvantages, we introduced a rigid endoscope with an outer diameter of 3.1 mm in April 2022 and performed endoscopic hematoma removal procedures. We herein present our clinical experience with the novel endoscopic system and report on its effectiveness.

Materials and Methods

Inclusion criteria and endpoints

The Ethics Committee of Osaka Neurological Institute approved this study protocol (OR05-08). Patients with spontaneous intracerebral hemorrhage who met the indications for surgery from April 2022 according to the Japan Stroke Society Guideline 2021 for the Treatment of Stroke were included in this study.⁵⁾ Preoperative evaluation of cerebral arteries by magnetic resonance (MR) and/or computed tomography (CT) angiography was performed. Patients with vascular anomalies such as aneurysms or arteriovenous malformations were excluded, but not patients with intraventricular hemorrhage due to moyamoya and quasi-moyamoya disease. Pre- and postoperative Glasgow Coma Scale (GCS), complications such as perioperative rebleeding, and modified Rankin Scale (mRS) at discharge were retrospectively analyzed from hospital records. Hematoma volume was measured from preoperative and immediate postoperative CT using the ABC/2 method,⁶⁾ and hematoma evacuation rate was calculated. Moreover, the efficacy of the novel endoscopic system for hematoma evacuation was evaluated based on surgical records.

Surgical technique

A rigid endoscope with an outer diameter of 3.1 mm (Precision S 4K sinuscope AC, Stryker, Japan) connected to a 4K camera equipped with an indocyanine green (ICG) detection mode (1688 AIM 4K camera system, Stryker, Japan) was used. Assuming that a trajectory could penetrate the hematoma longitudinally, a 5 cm skin incision was made at the point of contact with the cranial surface. After creating a burr hole, which was enlarged to 1.5 cm in diameter, the hematoma was punctured with a ventricular tap needle. The trajectory was gradually enlarged to 6.7 mm with a Nelaton catheter, and a transparent introducer sheath (Neuroport; outer diameter, 10 mm; inner diameter, 9 mm; Olympus Co., Japan) was inserted. The endoscope was inserted freehand into the sheath, and, after reaching the hematoma, was aspirated and removed with a suction tube. The outer diameter of the suction tube was 2.5 mm with an irrigation channel of 1.5 mm diameter (Fujita Medical Instruments, Tokyo, Japan); thus, even relatively hard clots could be removed by dynamic scrubbing and irrigation of the hematoma.^4,7) Considering the possibility that the area with a highly organized clot was close to the original bleeding site, excessive manipulation was avoided, and the area was intentionally left untouched. When a certain amount of hematoma was removed, ICG was administered to check for active bleeding, and if confirmed, an electrocautery scalpel was connected to the suction tube, and the bleeding site was cauterized. The operation was terminated after confirmation of the absence of fresh bleeding fluorescing in the ICG detection mode.

Comparison with conventional 2.7 mm and 4.0 mm endoscopes

To demonstrate the visual improvement of the 3.1 mm 4K endoscope over the 2.7 mm high-definition (HD) endoscope (Olympus Co., Japan), the intraoperative scenes of both systems were shown in parallel. Moreover, to demonstrate the superior maneuverability of the 3.1 mm endoscope compared to the 4.0 mm endoscope, an intraoperative video of a case using the 4.0 mm endoscope (Karl Storz Endoscopy Japan K. K., Japan) was also added. To facilitate comparison, the magnification of each scene was adjusted equally.

To further demonstrate the difference in visual quality between the 2.7 mm endoscope (Machida Endoscope Co., Ltd., Japan) and 3.1 mm endoscope (Stryker, Japan), a static image of the chart paper was captured with the 4K camera (Stryker, Japan), both fixed with an endoscope holder. First, both endoscopes were fixed at a distance of 5 mm from the chart paper and images were presented at the same magnification for comparison (Fig. 1A and B). The 2.7 mm endoscope was then moved away from the chart paper to obtain the same field of view as the 3.1 mm endoscope (Fig. 1C). Finally, the magnification of the 2.7 mm endoscope was adjusted; thus, the field of view and the size of the squares were the same as those of the 3.1 mm endoscope (Fig. 1D).

Fig. 1.

The comparable images of the chart paper obtained with the 3.1 mm (A) and 2.7 mm (B) 4K endoscopes. The 2.7 mm endoscopic images at the distance of 8 mm (C) and with the ×1.3 magnification (D) are demonstrated.

Results

The sites of hematoma were the putamen in three cases, the thalamus and intraventricular in two cases each, and the cerebellum in one case. Hypertension was the cause in six cases and moyamoya and quasi-moyamoya diseases complicated by intraventricular hemorrhage in two cases each. One patient was taking antithrombotic medication (Table 1).

Table 1.

Summary of cases

	Age/sex	Past history	Hematoma location	Preop GCS	Preop HV or mGS	Postop HV or mGS	Evacuation percentage (%)	GCS at discharge	mRS at discharge
1	59/M	HT	R thalamus	6	24	19	20.8	14	4
2	35/M	Quasi-moyamoya desease	Cerebral ventricle	6	27	12	55.6	10	5
3	67/M	HT	R putamen	15	38.6 mL	15.1 mL	60.9	15	4
4	34/F	Moyamoya disease	Cerebral ventricle	6	27	25	7.4	14	3
5	86/F	HT	L putamen	6	41.1 mL	1.8 mL	95.6	10	5
6	82/F	HT	R thalamus	6	29	19	34.5	10	5
7	60/M	HT	L cerebellum	15	14.3 mL	1.35 mL	90.6	15	1
8	53/M	HT	R putamen	11	86.6 mL	3.7 mL	95.7	10	5

M, male; F, female; HT, hypertention; R, right; L, left; HV, hematoma volume; preop, preoperation; postop, postoperation; mGS, modified Graeb Score; mRS, modified Rankin Scale

Table 1 shows hematoma evacuation rate, GCS at discharge, and perioperative complications. All patients had no perioperative rebleeding or other surgery-related complications.

The novel endoscopic system allowed for more dynamic maneuvering of the suction tube and even a somewhat hardened hematoma could be scraped and easily removed by suction (VIDEO-1). In addition, the improved visibility of the surgical field increased the safety and reliability of the procedure. New bleeding that occurred during surgery could also be identified by ICG injection under fluorescence mode, allowing precise identification of the source of bleeding and reliable hemostasis (VIDEO-2).

The parallel demonstration of intraoperative scenes obtained with the 3.1 mm 4K endoscope and 2.7 mm HD endoscope clearly shows the visual superiority of the former system (VIDEO-3). In addition, the intraoperative video of the 4.0 mm endoscope shows frequent flicking of the suction tube and associated blurring of the endoscopic images, both indicative of interference between the surgical instrument and the endoscope.

The comparable images of the chart paper obtained with the 3.1 mm and 2.7 mm 4K endoscopes at the distance of 5 mm demonstrated the same size of the squares, but the field of view was narrower with the 2.7 mm endoscope (Fig. 1A and B). If the 2.7 mm endoscope was set at the distance of 8 mm, nearly identical field of view was obtained (Fig. 1C), but the size of the squares on the chart paper was reduced. By setting the magnification to 1.3, the field of view and the size of the squares became almost identical to those of the 3.1 mm endoscope (Fig. 1D); however, there was an obvious decrease in the quality of the image.

Representative Cases

Case 1 (patient 3 in Table 1)

A 67-year-old man with a history of hypertension was referred to our hospital due to sudden paresis on the left side. He presented with mild disturbance of consciousness of Japan Coma Scale (JCS) I-1, dysarthria, and grade 2 paresis of the left extremities according to manual muscle testing (MMT). A CT scan of the head showed a right putaminal hemorrhage with a hematoma volume of 51 mL (Fig. 2, top row). MR angiography showed no vascular abnormality and emergent endoscopic hematoma evacuation was indicated.

Fig. 2.

The preoperative (upper row) and postoperative (lower row) computed tomograms of case 1.

The preoperative computer tomography (CT) scan demonstrated a right putaminal hemorrhage with a hematoma volume of 51 mL. The postoperative CT scan showed residual hematoma to be 20 mL in volume.

The postoperative CT scan of the head showed a residual hematoma volume of 20 mL (Fig. 2, lower row). The patient's postoperative course was uneventful with improvement of consciousness to JCS 0 and MMT of the left extremities to grade 3 (VIDEO-1).

Case 2 (patient 6 in Table 1)

An 82-year-old woman who had a history of cerebral infarction and was taking clopidogrel was admitted to an emergency department with sudden onset of vomiting and altered consciousness. CT showed acute hydrocephalus due to right thalamic hemorrhage and ventricular perforation, and she was transferred to our hospital. Upon arrival, her level of consciousness was 6 on GCS, and pupils were 4 mm on the right without light reflex. The volume of the hematoma calculated from the repeated CT scan was 157.2 mL (Fig. 3, top row). CT angiography showed no abnormality of the intracerebral vasculature. Therefore, emergency endoscopic hematoma evacuation was indicated.

Fig. 3.

The preoperative (upper row) and postoperative (lower row) computed tomograms of case 2.

The hematoma volume calculated from the preoperative CT scan was 157.2 mL.

Postoperative CT showed the residual hematoma to be 58.15 mL in volume and evacuation of the intraventricular hematoma including the contralateral side to the approach.

Postoperative CT showed a residual hematoma volume of 58.15 mL and evacuation of the bilateral intraventricular hematomas (Fig. 3, lower row). Her postoperative course was uneventful without rebleeding or other complications, and her level of consciousness improved to 10 on GCS. However, her mRS remained at 5, requiring enteral nutrition, and she was transferred to a convalescent hospital. (The operative video is shown as VIDEO-2.)

Discussion

Various clinical studies have been conducted on the indications for surgery for spontaneous cerebral hemorrhage. However, the results of the studies differ, and the final conclusion on the efficacy of surgical intervention remains unclear. The purpose of surgery is to reduce the pressure on the brain parenchyma and the hematologic toxicity caused by the hematoma. On the other hand, surgery cannot be performed without some damage. Although the randomized trials have failed to demonstrate the efficacy of craniotomy over medical therapy,^1,2) the minimally invasive techniques including the endoscopic approach are expected to show superiority over medical management.⁸⁾ Indeed, there are reports of better neurological outcomes with endoscopic treatment of thalamic, lobar, and ventricular hemorrhage than with craniotomy or ventricular drainage.^9-11) On the other hand, less hematoma evacuation and higher rebleeding rates have been reported in the endoscopic cohort.^12-14) The limited maneuverability of endoscopic surgery and poor visibility of bleeding sites serve as factors that make reliable hematoma removal and hemostasis difficult.

When performing endoscopic hematoma repair in the confined space of a sheath, it is important to ensure the operability of the surgical instruments. For this reason, endoscopes with a smaller diameter of 2.7 mm have been used. However, the narrower diameter of endoscopes directly reduces visibility due to a decrease in light intensity and resolution. For this reason, the use of 4-mm-diameter endoscopes has been reported, but this greatly limits the maneuverability of the instruments.

In the operation using the 3.1-mm-diameter 4K endoscope introduced in our hospital, good visibility is ensured because it has sufficient light intensity and resolution, while the suction tube is fully operable with respect to the 9 mm inner diameter of the sheath. This is evident from the fact that the area occupied by the 4-mm-diameter endoscope is 12.56 mm² (19.7%) of the 63.6 mm² area of the 9-mm-diameter sheath, while the area occupied by the 3.1-mm-diameter endoscope is only 7.54 mm² (11.9%). On the other hand, the visibility of the 3.1-mm-diameter endoscope does not decrease excessively as in the case of the 2.7-mm-diameter endoscope, and the high image quality (4K) of the endoscope maintains it at a satisfactory level.¹⁵⁾ There are no reports on the use of a 3.1 mm rigid endoscope for hematoma removal, and this system offers a new option for endoscopic treatment of spontaneous intracerebral hemorrhage.

The rate of hematoma removal in this series was not as high as in previous reports. This may be due to the fact that we aim to reduce the mass effect and not to completely remove the hematoma. In cases complicated by intraventricular hematoma, we aimed to avoid hydrocephalus by removing the clot to establish adequate cerebrospinal fluid flow. After we realized the improved operability and visibility during endoscopic intervention by using this novel system, the surgical policy was changed to aggressively remove the hematoma, resulting in an improved intraparenchymal hematoma removal rate in the second half of the series.

In intracerebral hemorrhage surgery, hemostasis of the bleeding source has usually been achieved before surgery, and rebleeding is often attributed to the surgical maneuver. The novel endoscopic system used in this series ensures sufficient visibility of the surgical field, maneuverability of the instruments, and precise detection of the bleeding site through the ICG mode. These features facilitate reliable hemostasis, allowing aggressive hematoma removal without the incidence of rebleeding. Although the prognostic impact of hematoma toxicity from residual hematoma remains controversial, we believe that the establishment of a technique that allows for more reliable and complete hematoma removal has the potential to demonstrate the efficacy of surgical intervention over medical therapy.

Conclusion

The use of a high-resolution 3.1-mm-diameter rigid endoscope for hematoma removal provided both good visibility and instrument maneuverability. As a result, the reliability of hematoma aspiration and hemostasis was increased, and more aggressive hematoma removal without rebleeding became feasible. To date, there are no reports on the use of a 3.1 mm rigid endoscope for hematoma removal, and we believe that the introduction of this method will help to demonstrate the superiority of surgical intervention over medical therapy.

Conflicts of Interest Disclosure

The authors declare no conflicts of interest.