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Year : 2022  |  Volume : 25  |  Issue : 7  |  Page : 1056-1060

Burr hole and craniotomy in the treatment of subdural hematoma: A comparative study

1 Department of Neurosurgery, Dicle University School of Medicine, Diyarbakir, Turkey
2 Department of Neurosurgery, HSU Gaziyasargil Training and Research Hospital, Diyarbakir, Turkey
3 Department of Radiology, Dicle University School of Medicine, Diyarbakir, Turkey
4 Department of Physical Medicine and Rehabilitation, HSU Gaziyasargil Training and Research Hospital, Diyarbakir, Turkey

Date of Submission11-May-2021
Date of Acceptance25-May-2022
Date of Web Publication20-Jul-2022

Correspondence Address:
Dr. H Ozevren
Department of Neurosurgery, Dicle University School of Medicine, Diyarbakir, 21280
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/njcp.njcp_1511_21

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Aim: This article aims to study the clinical outcomes in patients with chronic subdural hematoma (CSDH) who underwent burr hole drainage or craniotomy. Patients and Methods: The length of hospitalization, Glasgow outcome scales (GOS) of patients undergoing burr-hole drainage or craniotomy, were evaluated and compared statistically. In this study, we also evaluated the relationship by receiver operating characteristic (ROC) analysis. Results: The sex and age distribution and specific clinical parameters of the patients were investigated. In this study, we provide the evidence of the GOS and length of hospitalization findings of the patients and the superiority of burr hole drainage over craniotomy. Conclusions: Chronic subdural hematoma responds better to burr hole drainage with shorter hospitalization and improved Glasgow score.

Keywords: Burr hole drainage, chronic subdural hematoma, craniotomy

How to cite this article:
Ozevren H, Cetin A, Hattapoglu S, Baloglu M. Burr hole and craniotomy in the treatment of subdural hematoma: A comparative study. Niger J Clin Pract 2022;25:1056-60

How to cite this URL:
Ozevren H, Cetin A, Hattapoglu S, Baloglu M. Burr hole and craniotomy in the treatment of subdural hematoma: A comparative study. Niger J Clin Pract [serial online] 2022 [cited 2022 Aug 8];25:1056-60. Available from:

   Introduction Top

A subdural hematoma is a collection of blood between the dura and arachnoid membrane surrounding the brain.[1] Chronic subdural hematoma (CSDH) develops for three or more weeks and is often caused by mild to moderate head trauma.[2] Symptoms of CSDH range from headaches, behavioral changes, focal deficits, seizures, hemiparesis, memory loss, and even death.[3]

CSDH has been one of the neurological disorders most frequently encountered in outpatient clinics in daily practice.[4] CSDH evacuation is one of the most common surgical procedures in neurosurgery.[5] The two most commonly used surgical techniques accepted by neurosurgery in CSDH evacuation are burr holes and craniotomy.[6] Surgical evacuation by drainage through the burr hole is the most widely accepted procedure for CSDH. In craniotomy, it is not accepted much because the operation time and risk, and post-op follow-ups are longer.[4],[7],[8],[9]

CSDH occurs gradually with bleeding from parasagittal vessels after head trauma. The most important assistant imaging method is a magnetic resonance imaging (MRI) or computed tomography (CT) when deciding to evacuate the hematoma of the patient who applied to the clinic to the neurological symptoms or clinical follow-up after the evacuation.[10]

CSDH is more common in the elderly, as they have an atrophied brain and are sourced from tears in the vein after trauma. It is more common in men in societies because they are often exposed to trauma. CSDH is similar in men and women in the same age range.[11],[12]

Glasgow outcome scale (GOS) is a simple measure of functional outcome that shows the degree of improvement in the follow-up of patients. It is used to evaluate the preoperative and postoperative clinical values of the patients or the healing process of the given medical treatment.[12],[13]

Clinically, CSDH can be treated with surgical evacuation or close observation, but surgical evacuation options remain the subject of debate. Burr hole drainage might be recommended due to shorter hospital stays and the better recovery rate in GOS.

   Methods Top

A multicenter retrospective study was conducted on 156 patients who had undergone burr hole drainage or craniotomy for CSDH between April 2014 and November 2019. The patients were between 1 and 85 years old. Patients with chronic subdural hematoma were diagnosed radiologically after CT, as in [Figure 1]. We excluded patients with a diagnosis of recurrent CSDH and infection. The length of stay in the hospital and GOS of patients undergoing burr-hole drainage or craniotomy were evaluated and compared statistically.
Figure 1: (a–c) Burr hole drainage; Preop and postop computed tomography images of a patient with left frontoparietal CSDH, (d–f) Craniotomy; Preop and postop computed tomography images of a patient with right frontoparietal CSDH (Preop, preoperative; Postop, postoperative; CSDH, chronic subdural hematoma)

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Ethical approvals

Patient records were included in the study after securing necessary permissions and approvals from the ethics committee (E-10477; 2021).

Statistical analysis

The length of hospitalization of patients undergoing a burr hole drainage or craniotomy was compared statistically. GOS of patients undergoing burr hole drainage or craniotomy were compared preoperatively and postoperatively. Statistical significance was analyzed using the student's t-test and the paired sample t-test. The values were given as mean ± standard deviation (min-max). P < 0.05 was considered significant. In this study, we also evaluated the relationship by receiver operating characteristic (ROC) analysis.

Surgical procedures

Burr hole drainage and craniotomy procedures are frequently applied in all clinics and accepted by the authors. The frequency of surgical procedures varies according to the clinics.

Burr- hole drainage

Burr hole drainage is performed under a general anesthetic. Placing single or double burr holes is a surgical procedure with a burr hole in the frontal region and/or a burr hole in the parietal region. The exact location of the burr hole is estimated with the help of a CT or MRI scan taken preoperatively. The dura is cauterized and opened. Suction irrigation is used to remove the clot, and the pseudomembrane is opened. After the burr holes are drilled, we ensure that irrigation. After the hematoma is evacuated, a drain is inserted through the burr hole to drain the remaining hematoma [Figure 1]a, [Figure 1]b, [Figure 1]c.


A craniotomy is performed under a general anesthetic. A temporary flap is elevated in the skull above the area where the hematoma is located. The hematoma is kindly removed using suction and irrigation, where it is washed with warm saline. After the procedure, the part of the skull is placed in place and fixed using silk or screws [Figure 1]d, [Figure 1]e, [Figure 1]f.

   Results Top

In the present study, 156 patients (125 men and 31 women) were selected. The study included 102 burr hole drainage and 54 craniotomies, except for those who were excluded. The mean age was 56.05 ± 23.68 (1–85 years), of which 56.71 ± 22.92 (1–84 years) were males and 53.36 ± 26.78 (2-85 years) were females. The ages of the patients were compared, but there was no statistically significant difference between their genders (P = 0.524). Features on admission were headache 86 (55%), behavioral changes 55 (35%), focal deficit 47 (30%), hemiparesis 31 (20%), seizures 23 (15%), memory loss 16 (10%), respectively [Figure 2]a. There is a statistically significant difference in terms of length of hospital stay compared to patients who underwent burr hole drainage (9.34 ± 5.44 (4–24) days) or craniotomy (12 ± 6.94 (5-26) days) (P = 0.016) [Figure 2]b. There is a statistically significant difference in terms of GOS compared to patients who underwent burr hole drainage; preoperative 4.18 ± 0.8 (2–5) and postoperative 4.38 ± 1.08 (1–5) (P = 0.006) [Figure 2]c. There is a statistically significant difference in terms of GOS compared to patients who underwent craniotomy; preoperative 3.65 ± 1.14 (2–5) and postoperative 3.94 ± 1.09 (1–5) (P = 0.025) [Figure 2]d.
Figure 2: (a) The hospital admission symptoms of the patients with CSDH, (b) Mean hospitalization days of the burr hole drainage and craniotomy; (c, d) Mean preop and postop values of the GOS of burr hole drainage, and craniotomy, statistically compared. (*P < 0.05 indicates a statistically significant difference; CSDH, chronic subdural hematoma; GOS, Glasgow outcome scale)

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In our study, the selectivity, sensitivity, and the area under the curve (AUC) values were determined by ROC analysis. When GOS preoperative and postoperative results were compared; Burr hole drainage was (AUC: 0.65, 95% Cl: 0.57–0.72, P < 0.001); while craniotomy was (AUC: 0.58, 95% Cl: 0.47–0.69, P = 0.161). When the length of stay in the hospital for the burr hole drainage and craniotomy were compared (AUC: 0.64, 95%: 0.55–0.73, P < 0.01) [Figure 3]a, [Figure 3]b, [Figure 3]c.
Figure 3: ROC Curve Analysis; the GOS (preop vs. postop) (a) Burr hole drainage, (b) Craniotomy; (c) The length of stay in the hospital (burr hole drainage vs. craniotomy). (ROC, receiver operating characteristic; GOS, Glasgow outcome scale; AUC, the area under the curve; Preop, preoperative; Postop, postoperative)

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   Discussion Top

CSDH is a stale aggregation of blood or the blood's destruction products that accumulate between the arachnoid membrane and the dura membrane. The most widely accepted pathophysiological expression of CSDH is that, after a mild head trauma, the bridged vessels tear, and then hemorrhage gradually forms with hematoma.[14] A minor head injury has often been reported as the main cause of CSDH development but is often seen in those who do not remember the trauma in their anamnesis.[15] In particular, approximately 30% to 50% of cases after the age of 65 do not have a history of trauma.[16],[17]

CSDH period involves inflammation, pro-collagens, and angiogenic factors; patients may not have symptoms and this period may take weeks to months.[18] At the end of the period, a gradual decrease in intracranial capacity occurs as a result of constant growth of the hematoma volume and capsule, and some symptoms may be caused by increased intracranial pressure.[19] These symptoms of chronic subdural hematoma admission to the hospital usually include headache, hemiparesis, unconsciousness, and seizures.[5] In our study, the symptoms of admission to the hospital are similar to the literature, as shown in [Figure 2]a.

Balser et al.[11] reported that there was a significant increase in the incidence of CSDH in the elderly compared to other age groups. In addition, most CSDH case series cohorts reported that they were aged 55–60 years, and some were over 70 years old.[20] In our study, it was shown that there was a significant increase in the incidence of CSDH in the 50–60 age group compared to other age groups.

In the study of Yang et al.,[15] the male gender was accepted as a potential risk factor for CSDH. In our study, the male gender was higher in line with the literature.

Surgical evacuation is considered in patients with CSDH when the hematoma results in clinical symptoms that have a mass effect on the underlying brain tissue.[5] Surgical methods of CSDH evacuation are generally safe, and postoperative patient follow-up results can often be satisfactory.[21] Although CSDH evacuation may be considered a simple surgical procedure, complications after surgery can have unwanted consequences such as disability and death.[22] Surgical treatment of CSDH is decided by CT or MRI scan after a detailed anamnesis. Most patients with CSDH have undergone craniotomy or burr hole drainage over the world.[7],[12],[23]

In the study of Shim et al.,[24] burr hole drainage was shown to be the most effective method in the treatment of CSDH compared to craniotomy. Due to the short duration of the operation of burr hole drainage, the small suture incision, and the fact that it can be performed with local anesthesia, patients recover and mobilize in the early period. Similar to the literature in our study, the burr hole drainage method was shown to be superior to craniotomy in terms of the length of stay in the hospital, as shown in [Figure 2]b.

GOS is one of the first and most widely used functional outcome measures in head injuries, bleeding, and stroke. This study gives us knowledge about the healing of patients with neuronal damage caused by CSDH using GOS, according to the patient's ability to do specific tasks; death, herbal life, extreme disability, moderate disability, and marked improvement.[12],[13] King et al.[25] assessed outcomes of patients with traumatic brain injury by GOS and demonstrated long-term clinical follow-up results. In our postoperative clinical follow-ups, there was a significant difference in the patients with a burr hole drainage in recovery when comparing the patients with burr hole drainage and craniotomy, as shown in [Figure 2]c and [Figure 2]d.

Burr hole drainage, when compared to craniotomy, according to the sensitivity, selectivity, and AUC values detected by ROC analysis, was concluded to be superior.

The limitations of this study are the number of patients and the lack of longer follow-up, so it cannot be generalized to all patients with CSDH.

   Conclusion Top

CSDH was mostly seen in older patients and the male gender. The complaints of patients admitted to the hospital were frequently caused by headaches. Patients with CSDH who underwent burr hole or craniotomy were compared according to the hospital stay length and GOS criteria; burr hole drainage application was found to be significantly more beneficial. We thought that the burr hole drainage method should be more beneficial for CSDH patients.

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Conflicts of interest

There are no conflicts of interest.

   References Top

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  [Figure 1], [Figure 2], [Figure 3]


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