Chronic subdural hematoma (CSDH), first introduced by Wepfer in 1656, refers to the space-occupying lesion caused by slow hemorrhage between the dura of the brain and its arachnoid and a collection of blood in the cerebral subdural space. In most patients, clinical symptoms occur after presence of the lesion for over 3 weeks.^[@R1],[@R2]^ Chronic subdural hematoma is a common disease in neurologic practice. It is more common in middle-aged and older patients. Before the computed tomography (CT) and magnetic resonance imaging (MRI) technology was invented, erroneous diagnosis and treatment happened frequently. Presently, the CT and MRI technology enables correct diagnosis on the disease, and yet, surgical treatment has been the main solution for decades because most of the patients have progressive hematomas. In recent years, although it has been reported that atorvastatin can partially cure CSDH,^[@R3]^ surgical treatment remains as the only option for those who have failed to recover with medication. With China\'s aging population growing, the traditional definition of the aged population (at the age of 60--79) has become outdated because the average life span of the population in developed regions has reached over 80 years, which indicates the emergence of the super-aged population (at the age of 80 or above). In general, the number of patients in demand for CSDH diagnosis keeps increasing as the aging population rises. In terms of surgical treatment, since older patients have more underlying diseases, they have to face a greater surgical risk or even death.^[@R4]^ In fact, except for the age of a patient, the level of surgical risk is also associated with the degree of surgical invasion. In this paper, a report on the CSDH patients who had been cured with the YL-1 needle was provided, in which, it was held that the YL-1 needle was safe in the treatment for the super-aged CSDH patients, and the aged ones, as well.

DATA AND METHODS
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General Information
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Thirty-six patients with CSDH treatment with the YL-1 needle from May 2012 to December 2016 were selected from the hospital and divided into 2 groups, including a super-aged group composed of 17 patients at 80 to 90 years old and an aged group having 19 patients at the age of 60 to 79. Both groups had male and female patients who were verified to meet the CSDH diagnostic standards through brain CT or MRI scanning. The selected patients mainly showed following clinical symptoms: headache, dizziness, nausea, vomiting, stumble, hemiplegia, and cognitive handicap. The brain CT results indicated that hematomas, in the thickness ≥1 cm and with the midline shift \>0.5 cm, could appear on the left or the right or both sides of the brain (Table [1](#T1){ref-type="table"}).

Operation Methods
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The piercing point at the center of the thickest layer of the hematoma is marked with a clip or bone wax (applicable to MRI scanning only) during CT or MRI scanning without damaging the functional areas, venous sinus, middle meningeal artery, etc. The 2 cm YL-1 needle supplied by Beijing WanTeFu Medical Apparatus Co, Ltd is selected for surgical treatment. After routine disinfection, the patient is draped and local anesthesia with lidocaine is performed. Then, an incision is made to 0.5 cm in the patient\'s scalp with a sharp blade. The puncture needle is connected to an electric trepanning drill before piercing. When it arrives at the piercing point, the surgeon can obviously feel the puncture needle piercing the hematoma. The side drainage tube is connected in advance and clamped before the core needle is removed when there is soy sauce-like or dark-red fluid flowing or spurting out, which indicates successful puncture; then, an apical drainage tube is immediately added and clamped while the clamp of the side drainage tube is removed so that the fluid can slowly flow. When the pressure is reduced, physiologic saline in 20 mL each time flow slowly in the apical drainage tube repeatedly and the side drainage tube is open to discharge the bloody fluid until the effluent becomes clear. Finally, the patient is sent back to the ward with the drainage tube fixed and the cut dressed. In the following 2 to 3 days, the patient needs to drain continuously. In patient with bilateral CSDH, the same procedures should be performed on the other side of hematoma. After operation, the patient should maintain a prostrate position in the ward. Infusion can be carried out as appropriate to facilitate brain reposition. In 1 to 2 days after operation, another CT scanning should be conducted to check whether there is residual flocculate. Meanwhile, 30,000 to 50,000 IU urokinase injection can be given to accelerate dissolution of flocculate, achieve thorough drainage, and reduce the possibility of recurrence. In 2 to 4 days after operation, the puncture needle can be removed according to the drainage volume and reposition of brain tissue. The cut should be sewed up after removing the puncture needle and the stitches should be taken out after a week (Figs. [1](#F1){ref-type="fig"}-[2](#F2){ref-type="fig"}).

![Sketch of YL-1 puncture needle. (A-B) Installation diagrams of YL-1 needle, mainly including a trepan, a 3-way needle and a blunt core needle in A and a side drainage tube and an apical drainage tube in B (see D); (C-E) Diagrams of intraoperative procedures and postoperative drainage; (F) P represents the piercing point with the cut of 0.5 cm in depth and the trepanned hole in the bone of 4.2 mm in diameter (red arrow).](jcrsu-29-e90-g001){#F1}

![Drainage operation of YL-1 puncture needle in chronic subdural hematoma trepanation. (A-C) Computed tomography images of a 71-year-old female patient before operation, on day 1 after the operation, and after 3 months from the operation; (D-F) computed tomography images of an 86-year-old male patient before operation, on day 1 after the operation, and after 3 months from the operation.](jcrsu-29-e90-g002){#F2}

### Follow-Up Visits

The periods of follow-up visits varied from 10 months to 4 years, during which, patients had received at least 2 CT reexaminations. Patients mainly paid follow-up visits by receiving outpatient service. Follow-up visit via telephone was also available.

Efficacy Observation
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Cure: The clinical symptoms and signs disappear and the imageologic examination result demonstrates complete removal of hematomas. Recurrence: In 3 to 6 months after the primary operation, it is demonstrated through CT scanning that the CSDH and the corresponding symptoms and signs recur in the same position as the original hematomas. Complications: The complications mainly include pneumocephalus and wound infection.

Statistical Analysis
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The SPSS18.0 software was used for data analysis. The measurement data were tested with the *t* test statistical method while the recurrence rates and complication incidence rates of both groups were analyzed with the Mann--Whitney *U* test of the rank-sum test. *P* \< 0.05 indicates that the difference between the 2 groups has statistical significance.

RESULTS
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General Information of Patients
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Among the 36 patients, 26 had head injuries in the previous 1 to 2 months, equal to 72.2% of the total number of patients of both groups in this paper while another few patients reported bleeding of undetermined origin; the number of male patients in both groups outperformed that of female patients, probably because male patients were more likely to have injuries. Hematomas were divided into left, right, and bilateral hematomas in terms of the position of occurrence. Hematomas were extensively distributed in the frontal, parietal, and temporal lobes in the thickness ≥1 cm (see Table [2](#T2){ref-type="table"}).

Comparison of Cure Rate, Recurrence Rate, Complication Incidence Rate, and Length of Stay Between Aged and Super-Aged Groups
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Patients in both groups were cured and discharged. Among the super-aged patients, there was 1 patient with pneumocephalus and 1 patient with wound infection, representing a complication infection rate of 11.8% while another patient had postoperative recurrence, showing a recurrence rate of 5.9%; as to the aged group, 2 patients developed pneumocephalus, representing a recurrence rate of 10.5% while other patients had no other complications. Meanwhile, in the aged group, there was 1 patient with recurrence, showing the recurrence rate of 5.3%. There is no significant difference in complication incidence and recurrence rates between the groups (*P* \> 0.05, Tables [3](#T3){ref-type="table"}-[4](#T4){ref-type="table"}). The length of stay of the super-aged group was 9.235 ± 2.948 days while that of the aged group was 7.316 ± 3.660 days. Although the former is slightly longer than the latter, it shows no statistical difference (*P* = 0.0917) (Fig. [3](#F3){ref-type="fig"}).

![Length of stay. No statistical difference between the 2 groups (*P* \> 0.05).](jcrsu-29-e90-g003){#F3}

DISCUSSION
==========

Pathophysiology of Chronic Subdural Hematoma
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Chronic subdural hematoma is commonly seen in the middle-aged and older population and head injury is an important cause of CSDH. Other factors that may lead to CSDH include excessive drinking, epilepsy, cerebrospinal fluid, disturbances of blood coagulation, and so on.^[@R5]^ Compared with the middle-aged population, with the same external factors, the aged has a relatively higher incidence of CSDH. In addition, there are few reports on CSDH in teenagers. Therefore, the age factor plays a considerably important role in the incidence of CSDH. Aging is not only associated with endocrine changes but also a direct factor leading to atrophy of brain. Hence, CSDH may called a physiologic atrophy-related senile disease. The pathophysiologic process of CSDH indicates that even a small amount of bleeding due to a light head injury can evolve into inflammatory reaction; in a few days, the fibroblasts invade the blood clots and form an envelope between the visceral layer and the parietal layer while the outer layer of the envelope, which is stimulated by the growth factors of vascular endothelial cells, forms a number of immature new vessels that break repeatedly; at the same time, fibrin breakdown products increase due to plasmin hyperfunction, resulting in loss of blood coagulation function and continuous growth of hematomas.^[@R6],[@R7]^ The characteristic change of CSDH refers to the repeated angiorrhexis of newly formed immature vessels induced by the growth factors of vascular endothelial cells, which creates a vicious circle and further leads to slow growth of hematoma. Therefore, to address both the symptoms and root causes, the space-occupying hematomas should be removed and more importantly, the basic materials of vascular endothelial cells (ie, coagulation fragments) should be eliminated.

Treatment of Chronic Subdural Hematoma
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The development of CSDH is based on the above-mentioned pathophysiologic process. Hence, in the state of local anesthesia, hematomas can be removed through trepanation, rinsing, and postoperative drainage while the growth factors of vascular endothelial cells and anticoagulant factors in the hematomas can be eliminated at the same time so that the patient can be cured. At present, the traditional sphenotresia accompanied by drainage is still the major clinical treatment method for CSDH. Compared with bone flap craniotomy, it is considered to be a "minimally invasive keyhole operation." Yet, it is not comparable to the YL-1 puncture needle CSDH trepanation and drainage operation in terms of the degree of invasion. In addition, the traditional trepanation and drainage operation cannot avoid such postoperative complications as infection, brain injury, intracranial hemorrhage, leakage of cerebrospinal fluid, and epilepsy.^[@R8]^ Further, in the previous reports, we^[@R9]^ have pointed out that compared with the traditional sphenotresia and drainage, the YL-1 puncture needle CSDH trepanation and drainage operation has obvious advantage in reducing the postoperative complication incidence and recurrence rates. Meanwhile, the YL-1 puncture needle CSDH trepanation and drainage operation, similar to the traditional trepanation and drainage operation, is characterized in intraoperative rinsing and postoperative drainage; in addition, it is convenient and time-saving, with the averaged time of operation ranging from 15 to 30 minutes; besides, its exceptional performance in reducing the degree of invasion has effectively relieved patients' pain.^[@R10]^ With the advantages above, the operation is suitable for the super-aged patients having various underlying diseases because they usually have poor cardiorespiratory function. The degree of invasion and the time of operation play an important role in determining whether they can come through the operation or not. The above-mentioned characteristics of the YL-1 puncture needle make the trepanation and drainage operation an effective solution to different indications, especially for the super-aged patients. Thanks to the application of YL-1 puncture needle to the operation, oral anticoagulant is no longer an absolute contraindication.

It should be specifically noted whether the application of YL-1 puncture needle to CSDH treatment can outperform neuroendoscopic treatment. Neuroendoscopic treatment is an emerging program that requires a greater number of patients and professional reports to gain its own advantages. Presently, it allows open diaphragm of multilocular hematomas under endoscope, which remains as its primary advantage.^[@R11]^ However, multilocular CSDH has a low incidence rate. Moreover, the cranial hole in neuroendoscopic treatment is much larger than that in the treatment with the YL-1 puncture needle. In addition to the cranial hole, the former shows poorer performance in preoperative preparation, physician training, and time of operation compared with the latter.^[@R12]^

Reflection of Similar Efficacy of YL-1 Puncture Needle Treatment for Super-Aged and Aged Chronic Subdural Hematoma Patients
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Postoperative recurrence is one of the main reasons for poor prognosis of CSDH patients. It is probably related to the age and hematoma volume of a patient.^[@R13]^ In terms of the efficacy of the YL-1 puncture needle, senile atrophy of brain---an important factor in postoperative recurrence---must be taken into account because the atrophy of brain will reduce the intracranial pressure, retard the postoperative brain reexpansion, and cause difficulty in hematoma drainage. Therefore, the treatment for super-aged CSDH patients should meet the following requirements as possible: the time of operation should be short while the hematomas should be thoroughly rinsed because, as mentioned above, residual coagulation fragments can lead to postoperative hematoma recurrence; after operation, the intracranial pressure should be increased as appropriate because the super-aged patients usually have multiple underlying diseases that prevent brain reexpansion with the fluid replacement therapy; patients are required to maintain a prostrate position or the trendelenburg position after operation to speed up the brain reexpansion; the use of urokinase should be reduced as possible according to the postoperative CT scanning results; in patient with poor rinsing and slight fall in the CT values, intracavitary injection of urokinase in hematomas can be performed to dissolve the blood clots; unnecessary extension of the drainage time should be prevented because, for the super-aged patients having severe atrophy of brain, extension of the drainage time cannot facilitate brain reexpansion; instead, it will increase the probability of postoperative complications. Hence, in 1 to 2 days after operation, if the effluent indicates drainage of cerebrospinal fluid, the drainage tubes should be removed; and if no obvious contraindication is observed, oral atorvastatin can be applied to the CSDH patients from the first day after operation. So far, it has been widely accepted that atorvastatin is efficient in stabilizing the newly formed vessels.^[@R3]^

Since the treatment with YL-1 puncture needle for the super-aged CSDH patients and the aged patients has similar efficacy, we have sound reasons to recommend that the age limit to the CSDH patients having surgical indications be lowered to 90 or above so that the patients can turn to the surgical treatment with the YL-1 puncture needle, which is a life-saving straw for those patients with ineffective treatment with atorvastatin. Yet, it is preferred to collect a larger number of patients to support the conclusion. According to Chen,^[@R10]^ the treatment with the YL-1 puncture needle for 697 CSDH patients, including the 98-year-old one(s), has satisfactory efficacy. Thus, the authors of this paper agree upon Chen\'s opinion that the treatment method is worth recommending.

Xifeng Fei and Yi Wan contributed equally to this work

The authors report no conflicts of interest.

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Main Clinical Symptoms of Chronic Subdural Hematoma Patients

  Symptom Age        Headache   Dizziness   Nausea and Vomiting   Hemiplegia   Stumble
  ------------------ ---------- ----------- --------------------- ------------ ---------
  Aged group         13         8           6                     6            5
  Super-aged group   11         5           0                     7            3

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General Information of Patients

                                                     Super-Aged Group   Aged Group
  -------------------------------------------------- ------------------ ------------
  Number of patients                                 17                 19
   Male                                              11                 15
   Female                                            6                  4
  Hematoma position                                                     
   Left frontal, parietal, and temporal lobes        5                  8
   Right frontal, parietal, and temporal lobes       8                  6
   Bilateral frontal, parietal, and temporal lobes   3                  5
  Having a history of head injury                    14                 12

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Recurrence Rates of 2 Groups

  Groups             n    Nonrecurrence (%)   Recurrence (%)   Z       *P*
  ------------------ ---- ------------------- ---------------- ------- -------
  Super-aged group   17   16 (94.1)           1 (5.9)          0.080   0.936
  Aged group         19   18 (94.7)           1 (5.3)                  

###### 

Complication Incidence of 2 Groups

  Groups             n    Noncomplication (%)   Complication (%)   Z       *P*
  ------------------ ---- --------------------- ------------------ ------- -------
  Super-aged group   17   15 (88.2)             2 (11.8)           0.116   0.907
  Aged group         19   17 (89.5)             2 (10.5)                   
