|Year : 2014 | Volume
| Issue : 1 | Page : 6-13
Chronic subdural hematoma: complication avoidance
Ahmed Abdel Salam Shakal, Ehab Ezzat El Gamal, Ashraf Mohamed Farid
Department of Neurosurgery, Faculty of Medicine, Tanta University, Tanta, Egypt
|Date of Submission||02-Nov-2013|
|Date of Acceptance||25-Dec-2013|
|Date of Web Publication||7-Apr-2014|
Ashraf Mohamed Farid
Department of Neurosurgery, Faculty of Medicine, Tanta University, Tanta
Background and objective
Chronic subdural hematoma (CSDH) is defined as the presence of a typical neomembrane, typical liquefied blood within the hematoma cavity, and 3 weeks of more of acute subdural hematoma. It has been classified into separate, laminar, homogenous, and trabecular types. This study analyzed the complications after burr hole evacuation in CSDHs and the best methods to avoid or at least minimize them.
Materials and Methods
A total of 28 patients who were suffering from complications after evacuation of CSDH were analyzed. Data on patients and treatment protocol were collected. Medical problems were also managed. Complications were studied as regards their causes and avoidance.
The highest incidence of complications is observed in the seventh decade of life. Recurrence was the most common complication especially in the separate type. The recurrence rate was higher among patients operated through a single burr hole. Extradural hematomas, although rare, were observed in three patients. Acute subdural hematoma and cerebral infarction had the worst prognosis.
Subgaleal dissection and insertion of a subgaleal drain are important for absorption and suction of the residual air and blood. In addition, intraoperative copious saline irrigation and postoperative meticulous follow-up are important for patients with a high risk of recurrence, especially those with hematomas of the separate type. During evacuation of the hematoma, we must avoid sudden decompression of the brain as it leads to cerebral infarction or intracranial hemorrhage. It is important to inform the anesthetist before performing the drainage that the blood pressure should be closely monitored and maintained at normal levels while infusing normal saline during surgery to avoid hypotension, which may lead to infarction. Any source of blood from the extradural space must be adequately dealt with.
Keywords: Chronic subdural hematoma, hepatic patients, recurrence, separated type
|How to cite this article:|
Shakal AS, El Gamal EE, Farid AM. Chronic subdural hematoma: complication avoidance. Tanta Med J 2014;42:6-13
| Introduction|| |
The first clear account of chronic subdural hematoma (CSDH) was given by neurosurgeons from Paris in 1817. In 1938, Davidoff and Dyke published their classic treatise on CSDH. In the pre-computed tomography (CT) era, the diagnosis was largely clinical and many patients died undiagnosed or suffered from persistent disability because of a delay in diagnosis . One way to define CSDH is by the presence of a typical neomembrane, typical liquefied blood within the hematoma cavity, and acute subdural hematoma for 3 weeks or more .
CSDH has been very commonly encountered in routine neurosurgical practice for more than 100 years. It is generally accepted that the initial bleeding in CSDH is likely to have a venous origin, as an arterial bleed will lead to early symptoms from acute brain compression .
Yamamoto et al.  and Tokmak et al.  reported that CSDH is an inflammatory process that begins as a local inflammatory reaction of the dura mater in response to injury or external stimuli such as blood or cerebrospinal fluid. Blood in the subdural space then evokes an inflammatory reaction resulting in the deposition of fibrin, which is followed by organization and formation of subdural neomembranes with an ingrowth of fragile neocapillaries. Ultrastructural studies of these neocapillaries have shown that these neovascular structures, called macrocapillaries, are abnormally permeable and have large gap junctions with an absent or incomplete basement membrane. Therefore, exudation through the macrocapillaries may play an important role in the enlargement of a CSDH. A high content of plasminogen and plasminogen activator within the outer neomembrane enhances fibrolytic activity; hence, the newly formed clots are defective and cannot result in effective hemostasis. This situation results in frequent effusions of plasma or rebleeding from the neomembranes into a subdural collection.
CSDHs may become multiloculated, with pseudomembranes separating discrete cavities, each with liquefied hematomas of different ages; this is due to multiple recurrent bleeding into the cavity occurring over a period of time. Surgical evacuation by removal of the outer membrane of the hematoma in which plasminogen and plasminogen activator are highly concentrated decreases the cumulative effect and interrupts the cycle of fibrinolysis. The ratio between effusion and rebleeding on the one hand, and reabsorption of the subdural collection on the other, determine whether the CSDH will resolve, persist, or increase in size [6-8]. In this study, we managed only the complicated cases that occurred after surgical management of CSDH and admitted to Neurosurgery Department, Tanta University Hospitals, to analyze and avoid this complication.
| Materials and Methods|| |
A total of 28 adult patients (21 men and seven women) admitted to Neurosurgery Department, Tanta University Hospitals, during the period from October 2006 to November 2010 with complications after burr hole evacuation of CSDH were analyzed.
Patients were managed on the basis of their history on presentation; the previous data available, especially previous images and classification; the presence of medical diseases such as liver disease, hemorrhagic diatheses, and cardiac disease; and anticoagulant use. Neurological examination and laboratory investigations were carried out (e.g. estimation of bleeding time, coagulation time, platelet count, prothrombin time, and concentration). CT of the brain was the main diagnostic tool for all patients with CSDH; urgent CT scanning was performed for patients who did not recover well or for those with neurological deterioration. MRI of the brain with contrast was indicated for patients with suspicion of subdural empyema. Radiographic parameters, such as hematoma location, density, transverse diameter, and midline shift more than 5 mm were recorded; possible confounding underlying brain conditions such as atrophy were also detected.
Although the classic two-burr-hole technique is the standard procedure for all patients with CSDH , there were two patients with hematoma recurrence who were operated previously using the single-burr-hole technique because of high anesthetic risk (class IV, American Society of Anesthesiologists). After induction of general endotracheal anesthesia, positioning the patient, and trephination, the dura in the frontal and parietal burr holes was incised at the same time in a cruciate manner. The dural edges were coagulated. The outer membrane of the hematoma was coagulated and dissected, which led to slow evacuation of the hematoma. The inner membrane was left intact to avoid any cortical damage. The hematoma cavity was irrigated with sterile warm tepid saline until the drained fluid became clear; irrigation was performed in all directions. The brain surface was visualized through both burr holes to assess potential re-expansion. The subgaleal space was dissected widely using a blunt dissector and a subgaleal drain was placed. This was achieved through a frontal skin incision, and the catheter was passed from the frontal to the parietal region, thus covering both burr holes. While irrigating, the parietal incision was closed first, allowing the hematoma cavity to be filled with saline before closure of the frontal incision. The drain was exteriorized through a separate stab incision and then connected to a closed system collection bag, which was placed under full suction. The patient was kept in the supine position until the closed drainage system was removed 48-72 h postoperatively. The patients received 2000-2500 ml fluid intravenously, guided by the central venous pressure (CVP) for the first 24 h; thereafter, the same amount was administered orally. Aiming at brain expansion, prophylactic antibiotics were administered for 7 days and anticonvulsants for 3 months . After surgery, patients were admitted to the intensive care unit and observed for an improvement in the level of consciousness and neurological deficit. Patients with complications (patients who developed extra-axial intracranial hemorrhage, empyema, or pneumocephalus) were reoperated, whereas patients with brain contusions or infarctions received conservative treatment in the intensive care unit. After evacuation of the hematoma, patients were observed for the degree of improvement in the level of consciousness and neurological deficit. Patients with complications either received conservative treatment or were reoperated upon according to the type of complication. Routine baseline CT was not requested for all patients, but was guided by the clinical picture.
Patients in a stable condition, who were treated with anticoagulants, were managed as follows: nonurgent patients, anticoagulants should be stopped 3 days preoperatively, administering the patients with fresh-frozen plasma, guided by the ProTime, international normalized ratio, and vitamin K levels (10-20 mg intravenously at ≤1 mg/min), and 1 U of platelets, guided by the platelet count and bleeding time. Urgent patients (those who have recurrence, extradural hematomas, massive pneumocephalus, massive acute subdural or intracerebral hematoma, or subdural empyema) were operated while receiving 1 U (250 ml) of fresh-frozen plasma and vitamin K intraoperatively. The guidelines are according to the ProTime (˜13 s) and the INR (˜≤1.4). As regards the decision for surgery, among patients who developed extradural hematomas, the indication for surgery was a hematoma size of greater than 30 cm, an MLS of greater than 5 mm, or a transverse diameter of greater than 15 mm on CT. Among patients with subdural hematomas, the indication for surgery was an MLS of greater than 5 mm and a thickness of greater than 10 mm, with correlations with clinical deterioration or comparable to the first presentation .
| Results|| |
The highest incidence of complications is in the seventh decade of life (three patients aged between 60 and 70 years, two patients aged above 70 years, one patient aged less than 40 years, and one patient aged less than 50 years. Recurrence was the most common complication (seven of 28 patients, 25%), followed by intracranial hemorrhage: both extradural (>15 mm) and subdural hematomas (>10 mm) were encountered (22%). Hepatic disease was the most relevant disease as a contributing risk factor (36%; bilharzial; assessed by preoperative ultrasound and liver function tests, and by communication with the Internal Medicine Department), followed by cardiac disease (25%; assessed through ECG and cardiological consultation). Both were correlated with recurrence and intracranial hemorrhage.
We assessed recurrence in patients with postoperative improvement of symptoms, followed by deterioration. The CT was the guide, compared with the initial CT. CT was requested if there was clinical deterioration. Data were collected from the referred patients; we assessed the enclosed images and medical reports, if present, in addition to patient history.
Recurrence rate in bilateral hematoma was higher in comparison with unilateral hematoma [two of four patients (50%) and five of 24 patients (21%), respectively]. Mixed density was the main CT finding (41%, more than 2 weeks). Recurrence rate was higher among patients operated through a single burr hole (two of 7 patients). Larger hematomas had a greater tendency for recurrence; six of seven patients' CT scans revealed CSDH of greater than 10 mm transverse diameter (86%) versus one of seven patients (14%) with CSDH that was 10 mm or lesser in transverse diameter.
CSDH is classified into stages: stage 1, the homogeneous stage, in which the hematoma exhibits a homogeneous density (low-high); the laminar stage, a subtype of stage 1, in which a thin high-density layer is present along the inner membrane; stage 2, the separated stage (including the gradation stage), defined as a hematoma containing two components of different densities with a clear boundary between them; stage 3, the trabecular stage, with features of high-density septa created by fibrosis (Nakaguchi et al., 2001). In our study, the recurrence rate of the separate type was the highest (including gradation stage; 57%), followed by the laminar type (29%); there was no recurrence of the trabecular type. Acute subdural hematoma and infarction had the worst prognosis with respect to recovery and postoperative level of consciousness. Larger hematomas had a greater tendency to be recurrent because the subdural space is larger than that found in smaller lesions [Figure 1], [Figure 2], [Figure 3], [Figure 4],.
| Discussion|| |
In this work, the age of the patients ranged from 3 to 81 years; the mean age of the patients was 60 years; the peak incidence was in the seventh decade of life. These results are similar to those of Cameron  and Brush . Four of our patients (14%) reported a history of trauma. In the studies by Brush  and Domenico et al. , a history of trauma was reported in 78 and 63% of patients, respectively. The discrepancy between our results and those reported by Brush  and Domenico et al.  could be explained by the fact that our study included only patients with complications whose hematomas were usually metabolic in origin. Ishikawa et al. , Chen et al. , Frati et al. , and Gurunathan  stated that the mean age at onset for CSDH was 63 years; it has an incidence of one to two cases per 100 000 inhabitants per year; this incidence increases to seven per 100 000 individuals among patients older than 70 years. The mortality rate for CSDH treated by drainage ranges from 0 to 8%, and accompanying conditions such as cardiac disease are the major causes of death . The recurrence rate of CSDH after surgery ranges between 2 and 37% .
At the time of recurrence, the CT density of hematomas in this study was mixed in 11 patients (41%), hypodense in nine patients (31%), and isodense in eight patients (28%). Ming  hypothesized that such a mixed density status occurred as a result of rebleeding into a chronic hematoma. The authors thus argued that if the operations of those patients were to be postponed for any reason, they should remain bed ridden until they undergo drainage to avoid any risk of new bleeding.
In this study, recurrence of the hematoma was the most common complication (25%). The highest recurrence rate was found in CSDHs of the separate type (57%; including the gradation stage), followed by the laminar type (29%) and the homogenous type (14%); no recurrence was observed in the trabecular type. These results are similar to those of Nakaguchi et al. , who attributed the highest recurrence rate of the separated type of CSDH (including the gradation stage) to its pathology, which is characterized by the presence of a high concentration of fibrinogen, fibrin monomer, and d-dimer, which leads to hyperfibrinolytic activity with a high tendency for rebleeding. Nakaguchi and colleagues therefore suggested that meticulous perioperative management and frequent postoperative follow-up examinations are necessary for managing this type of CSDH. Their study also attributed the higher recurrence rate of the laminar type of CSDH compared with the homogeneous type of CSDH to the greater vascularity of the former. Stanisic et al. hypothesized that no recurrence of the trabecular type was observed because of the low risk of bleeding from the hematoma capsule, which carries a large fibrous component. They considered this stage to be the resolution stage of CSDH on surgical inspection.
No subdural hematoma recurrence was observed among diabetic patients in this study. Yamamoto et al. reported that the recurrence rate was lower among diabetic than among nondiabetic patients, and they attributed this finding to higher osmotic pressure and increased platelet aggregation among diabetic patients, which lead to a decrease in exudation from the capillaries. Recurrence rate was higher in bilateral hematoma compared with unilateral hematoma, two of four patients (50%) and five of 24 patients (21%), respectively. Torihashi et al.  reported similar results. They attributed their result to the fact that patients with bilateral CSDH tend to have had a previous brain atrophy, which might lead to poor brain re-expansion after surgery.
In this study, postoperative recurrence rate was higher among patients operated through a single burr hole than among those operated through two burr holes. These results are also in accordance with those of Taussky et al. . Zomfen et al.  attributed the higher postoperative recurrence rate after a single burr hole craniostomy to the possibility that the hematoma itself is the promoter of its chronicity, and consequently, the goal of any surgical therapy is the removal of the hematoma fluid. Taussky et al. , after multivariate regression analysis, identified the number of holes as a single predictor for the postoperative recurrence rate (r2 = 0.12, P < 0.001). In their study, treatment of CSDH with only one burr hole was found to be associated with a significantly higher postoperative recurrence rate, longer hospitalization time, and a higher wound infection rate. The hypothesis of self-promoting hematoma accumulation is supported by laboratory studies showing that the hematoma fluid contains large concentrations of vasoactive cytokines, inflammatory mediators, and fibrinoloytic factors They also emphasized that the importance of hematoma fluid evacuation in preventing postoperative recurrence is further emphasized by the fact that the risk of recurrence is increased when the concentration of fibrinolytic factors remains high in the postoperative drainage fluid. Consequently, the success of any surgical intervention seems to be directly linked to the success or completeness of hematoma fluid evacuation. It seems logical that this goal is easier achieved using two burr holes rather than one, the same way a simple tin can is flushed out easier using two openings instead of one.
Abouzari et al.  concluded that postoperative head position affects recurrence rate. We are also convinced that patients should be kept in the supine position for 3 days postoperatively. In our series, what correlated to recurrence rates of those kept in sitting position are two cardiac patients of seven recurrences. Abouzari and colleagues reported recurrence rates of 2.3 and 19% for patients kept in the supine position and in the sitting position, respectively, for 3 days postoperatively; their study demonstrated that patients with a larger subdural space (brain atrophy, larger maximum transverse diameter of the hematoma) have a higher recurrence rate than patients with a smaller subdural space. They concluded that assuming an upright posture soon after operation is associated with an increased incidence of CSDH recurrence. However, Nakajima et al.  reported that assuming an upright posture soon after operation in cases of CSDH is not a risk factor for recurrence. Abouzari and colleagues attribute this discrepancy to the relatively smaller number of patients in the study by Nakajima and colleagues.
In this study, larger hematomas were found to have a greater tendency to recur because postoperatively the subdural space is larger than that found after removal of a smaller lesion. The postoperative recurrence rate for patients with hematomas that were 10 mm or smaller was 14% (one of seven patients) versus 86% for those with hematomas greater than 10 mm (six of seven patients) on CT before the first surgery. Stanisic et al. , reported a postoperative recurrence rate of 9% for patients with hematomas that were 10 mm or smaller, whereas the postoperative recurrence rate for patients with hematomas greater than 10 mm was 21%. Moreover, they concluded that frontal base type, midline shift more than 5 mm, presence of subdural clots in the cranial base type, and massive postoperative air collection are also associated with a high recurrence rate. They attributed the high recurrence of the cranial base hematomas to the higher rebleeding rate in hematomas with a cranial base extension because of a greater extent of feeding vessels from the middle meningeal artery and/or greater technical difficulty in evacuation of these hematomas. The frontal base type had a higher recurrence rate than frontotemporal base hematomas; according to their explanation, the former hematomas may be more difficult to evacuate adequately compared with the latter if the burr hole, for cosmetic reasons, is placed too far posteriorly. Hence, the evacuation may be insufficient. In addition, if the catheter is forced too far in the frontobasal direction, it may cause bleeding from the traumatized neomembrane. It is worth mentioning that they also reported that the subdural drain impairs the adhesion between the inner and outer membranes, hence leading to a risk for recurrence.
Although there is controversy regarding the insertion of a drain after burr-hole craniostomy, we believe that the insertion of drainage system decreases the incidence of recurrence rate as Markwalder, 1990  and Gurunathan , reported that closed system drainage decreases recurrence rate after burr-hole evacuation, the system could be simply applied & no infection rate and prevents early postoperative subdural collections. Their conclusion was based on a comparative study between patients with drains inserted and those without drains. In addition, they did not recommend a subdural drain. There is controversy about whether the position of the drainage catheter should be subdural or subgaleal. We are convinced that a subdural drainage catheter is associated with a high risk of subdural empyema; hence, we applied the drainage catheter in a subgaleal position in all our patients. Placement in the subgaleal space per se is not associated with infection. In addition, maintenance was under complete aseptic conditions (emptying, recording the rate of filling etc.). We did not culture samples from the drain and did not insert a subdural drain at all.
Gazzeri et al.  found the incidence of postoperative subdural empyema complicating subdural drainage to be 2% versus 0.3% in the case of subgaleal drainage systems in 224 consecutive adult patients with symptomatic CSDH. The mean age of the patients was 71.5 years (range 65-94 years): 146 were men and 88 were women. Diagnostic methods included CT scanning (218) and cerebral MRI scans (15). In addition, we believe that subgaleal drainage helps avoid the risk for an acute hemorrhage, which may follow the removal of a subdural drain.
In this study, the subgaleal space was dissected widely using a blunt dissector; thereafter, the closed drainage system was positioned through the frontal skin incision and passed from the frontal to the parietal region, thus leaving the drain over both burr holes. Nakaguchi et al.  reported a 9% recurrence rate for patients whose drainage system tip was placed on the occipital burr hole, whereas the recurrence rate for those whose drainage system tip was placed on the frontal burr hole was 1%. Therefore, we opted to place the tip of the drainage catheter accurately over the frontal burr hole, also removing subdural air. Yamamoto et al.  also performed closed system drainage using a silicone tube for 1-5 days; they considered that drainage helps in promotion of subdural fluid reabsorption and prevention of rebleeding. In their analysis of patients, 10 of 11 patients in the recurrent group had a frontal draining system, whereas 84 of 94 patients in the nonrecurrent group had a frontal draining system. They did not elaborate on the technical steps of insertion of the drain or whether the drain was subgaleal or subdural. They emphasized that if irrigation is performed completely, residual structures (intrahematomal membranes) should shrink and adhere to each other.
Beyond the position of drains, Gurunathan , in their study of 103 patients, reported that intraoperative saline irrigation decreases the recurrence rate of subdural hematoma as it leads to adequate and complete evacuation of the CSDH with its fibrinolytic agents. Yoshimoto and Kwak  added that irrigation allows refilling of the subdural cavity with saline, thus preventing the influx of air into the subdural space, which leads to pneumocephalus. Nakaguchi et al.  reported that patients with residual subdural air on CT scans obtained on the seventh postoperative day had a higher recurrence rate than those with no subdural air, which could be explained by the fact that presence of subdural air induces prolonged widening of the subdural space and disturbs adhesion between the inner and outer membranes, which is considered to be a necessary factor for cure of CSDH.
In this work, postoperative intracranial hemorrhage occurred in six patients (22% of complications): three patients developed extradural hematomas and the same number of patients developed acute subdural hematomas. All these patients were reoperated by urgent craniotomy. Good recovery occurred in four of these six patients. Gazzeri et al. , in his retrospective study conducted on 224 patients, reported postoperative complications in three patients: one patient developed a subgaleal empyema, which was treated with a surgical toilet and antibiotics; two patients suffered from partial motor seizures, which were managed successfully with anticonvulsant drugs; two other patients suffered from pneumonia, which resolved after antibiotic therapy. Two patients died while in the hospital, yielding a mortality rate of 0.9%: one of them, an 80-year-old patient, developed an acute subdural hematoma and multiorgan failure a few hours after the initial surgery and died 3 days later; the other patient (87-year-old) arrived at our surgical room in a coma and died 2 weeks later having not shown improvement after surgery.
Ford and Mclaurin  hypothesized that an extradural hematoma could occur as a complication after evacuation of CSDH, as a result of loss of intradural pressure on venous laceration and separation of the dura mater over a wide area. This view is substantiated by the observation that there is variation in adherence of the dura mater to bone between different individuals and even within the same individual, with least adherence in the temporal area and the greatest adherence along the suture lines.
In this study, in patients with bilateral hematomas, the two sides are evacuated during the same operation. In our study, two of four patients with bilateral hematomas developed recurrence (50%), whereas five of 24 patients with unilateral hematomas developed recurrence (21%). Torihashi et al.  operated upon 61 patients with bilateral hematomas, 35% of whom developed recurrence. They attributed their result to the fact that patients with bilateral CSDH tend to have had previous brain atrophy, which might lead to poor brain re-expansion after surgery. Poor brain re-expansion has been shown to be correlated with recurrence, and it is thought to create the potential for reaccumulation of blood. Kasta et al.  reported that evacuation of hematoma in one side before the other leads to distortion of the midline structure and failure of autoregulation of blood flow to the brain, resulting in intracranial hemorrhage or infarction.
Guzel et al.  and Mark et al.  reported the importance of informing the anesthetist that the blood pressure should be closely monitored and maintained at normal levels while infusing normal saline during surgery, as sudden decompression during drainage from the burr hole may result in a reduction in blood pressure and failure of autoregulation of brain blood flow, thus resulting in postoperative cerebral infarction.
In this work, 82% of patients showed good recovery, which is comparable with the results of the studies by Mark , who reported good recovery in 86% of his patients, and Cameron , who reported good recovery in 89% of his patients. Cameron reported that mortality among his patients (nine of 101) was attributable to internal capsule hemorrhage in four patients, myocardial infarction in two patients, massive pulmonary embolus in two patients, and acute pulmonary edema in one patient.
| Conclusion|| |
Subgaleal dissection and insertion of a subgaleal drain passing through the burr holes are important for absorption and suction of the residual air and blood; in addition, irrigation with copious amounts of saline intraoperatively and meticulous follow-up postoperatively are important for patients with a high risk of recurrence. During evacuation of the hematoma, we must avoid sudden decompression of the brain as it leads to cerebral infarction or intracranial hemorrhage. It is important to inform the anesthetist before performing drainage that the blood pressure should be closely monitored and maintained at normal levels while infusing normal saline during surgery to avoid hypotension, which may lead to infarction. Finally, any source of blood from the extradural space must be adequately dealt with [Figure 1], [Figure 2], [Figure 3], [Figure 4].
| Acknowledgements|| |
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]