This study evaluates the necessity of dural tenting sutures in craniotomies. The sutures elevate the dura, a layer between the brain and skull. Supposedly, by doing so, they prevent blood collecting between dura mater and the skull. These blood collections, called epidural hematomas, contributed greatly to postoperative mortality in the early days of neurosurgery. There have been several reports questioning the ongoing need for them in neurosurgery, thanks to modern hemostatic techniques. Moreover, it has been published in the literature, and is a common knowledge as well, that some neurosurgeons do not use these sutures at all, and do not have worse outcomes than their colleagues.

In this study, half of the randomly assigned participants will undergo craniotomy without dural tenting sutures and will be considered an intervention group. The other half will undergo craniotomy with these sutures.

In the early days of neurosurgery, epidural hemorrhages (EDH) contributed to a high mortality rate after craniotomies. Almost a century ago Walter Dandy reported dural tenting sutures as an effective way of preventing postoperative EDH. Over time, his technique gained in popularity and significance to finally become a neurosurgical standard.

Yet, there have been several retrospective reports questioning the ongoing need for dural tenting sutures. Dandy's explanation that the hemostasis under hypotensive conditions is deceiving and eventually causes EDH may be obsolete. These days, proper intra- and postoperative care, including maintenance of normovolemia and normotension and the use of modern hemostatic agents, may be enough for effective hemostasis. Evading of this suturing technique by some surgeons supports this argument even further.

Thus, there is a fundamental need to evaluate the necessity of dural tenting sutures in an unbiased, evidence-based manner.

Inclusion Criteria:

• male or female over 18 and under 75 years old
• qualified for an elective supratentorial craniotomy with a diameter of at least 3 cm
• Glasgow Coma Scale 15 preoperatively
• Modified Rankin Scale 0, 1 or 2 preoperatively

Exclusion Criteria:

• Coagulation abnormalities before the surgery
• Revision craniotomy
• Skull base surgery

The trial protocol, full study report, anonymised participant-level dataset and statistical code for generating the results will be made publicly available if all investigators agree to share the data.

Due to the nature of the surgical procedures, the surgeon and the rest of the OR medical team will be aware of the current subject's allocation. However, in each case, the specific OR team aware of the subject's allocation will be different from the investigators performing further evaluation of the given subject. The following study procedures will be in place to ensure double-blind administration of the study.

• Access to the randomization code will be strictly controlled.
• The surgeon will receive information on subject's allocation after commencing the surgery.

The study blind will be broken:

1. During interim monitoring, after recruiting the first 100 patients.
2. On completion of the clinical study and after the study database has been locked.
3. When patients' safety requires access to allocation data.