Till 1970s, craniotomy was the most commonly used method. Burr hole trephination for chronic subdural hematoma became the most preferred method from 1980s. In 1977, Twist drill craniotomy for chronic subdural hematoma was introduced. Closed system drainage after a Burr hole (BH) or a Twist drill (TD) became the most frequently used surgical method. Although nonsurgical treatment is often successful, trephination has more advantages, such as rapid resolution of the symptoms and short period of hospitalization. Nonsurgical treatment is possible in asymptomatic patients with a small CSDH. For the symptomatic patients with CSDH, trephination is the treatment of choice, either by BH or TD. In gray zone between surgery and medical treatment, shared decision making can be an ideal approach. For chronic subdural hematoma recurrences, repeated trephination is still effective for patients with a low risk of recurrence. If the risk of recurrence is high, additional management would be helpful. For the refractory CSDHs, it is necessary to obliterate the subdural space ¹⁾.

Chronic subdural hematoma treatment in the elderly include observation, operative burr holes or craniotomy, and bedside twist drill drainage. The decision on which technique to use should be determined by weighing the comorbidities and symptoms of the patient with the potential risks and benefits.

Chronic subdural hematoma are ideally treated with surgical drainage. Despite this common practice, there is still controversy surrounding the best surgical procedure. With lack of clear evidence of a superior technique, surgeons are free to base the decision on other factors that are not related to patient care.

Originally, CSDHs were treated by open craniotomy ^{2) 3) 4) 5)}. Later burr hole trephination (BHT) was adopted because it was less invasive with lower morbidity and recurrence rates when compared with standard craniotomy ^{6) 7) 8) 9) 10) 11)}.

The traditional methods include evacuation via a burr hole with closed system drainage with or without irrigation, two burr-hole craniostomy with closed system drainage with irrigation or craniotomy, with subdural drain or without drain placement.

Minicraniotomy (MC) emerged as an attractive alternative to BHT as it allows better visualisation of the subdural cavity, enabling better haemostasis and resection of membranes.

Although bedside twist drill evacuation may avoid operating room costs and anesthetic complications in an elderly patient population and allow earlier anticoagulation resumption treatment if necessary, there is also a risk of morbidity if uncontrolled bleeding is encountered or the patient is unable to tolerate the bedside procedure. However, bedside twist drill craniostomy is a reasonable and effective option for the treatment of subacute/chronic SDH in patients who may not be optimal surgical candidates ¹²⁾.

Subperiosteal vs Subdural Drain After Burr-Hole Drainage of Chronic Subdural Hematoma: A Randomized Clinical Trial (cSDH-Drain-Trial) ¹³⁾.

see Chronic subdural hematoma surgical techniques.

see Chronic subdural hematoma surgery complications.