Traumatic brain injury (TBI) remains a major public health problem globally. Indications for neurosurgical interventions following TBI can be broadly categorised as 1) evacuation of haematoma, 2) control of traumatic intracranial pressure (ICP), 3) elevation of depressed skull, 4) repair of skull base fractures with or without dural repair, 5) treatment of hydrocephalus and 6) cranial reconstruction. Decompressive craniectomy (DC) is a neurosurgical procedure that involves the removal of a section of the skull (bone flap) and expansion duraplasty which provides additional space for the swollen brain to expand, leading to a reduction in ICP and maintained or improved cerebral perfusion pressure. As an adjunct, Cisternal opening is a well-embedded microsurgical technique in neurosurgical practice for vascular and skull base pathologies. Its application in the context of TBI, in combination with insertion of an external drain which stays in place for a few days post-operatively, has been termed cisternostomy. The objective of this study is to compare the outcome of Cisternostomy and DC for the management of severe TBI in terms of the Glasgow outcome scale (GOS). For these two groups meeting the inclusion criteria will be divided based on the lottery method after a CT scan of the brain. Group A (DC) and Group B (Cisternostomy) for severe TBI. The rationale of the procedure lies in the recognition of the important contribution of the perivascular Virchow - Robin spaces to CSF circulation. In severe TBI, increases the inter-cisternal pressure that provokes a shift of fluid from the cisternal compartment to the brain parenchyma. Although DC brings the ICP to atmospheric pressure, it does not counter react the intracerebral pressure, which causes severe brain swelling and herniation. DC may further necessitate an additional operation for cranial reconstruction, termed as cranioplasty. In this situation, cisternostomy is useful in reversing this fluid shift alleviating brain edema and thereby lowering ICP. A standard ventricular drain will be placed in the cisternal compartment which will further help in controlling the raised ICP. This study will be conducted at the Department of Neurosurgery, Punjab Institute of Neurosciences, Lahore. Clinical evaluation of the patient will be done with regular follow-up for 6 months. Data of the GOS, duration on Ventilator, ICU stay and hospital stay along with extended GOS at 6 months will be recorded and analysed. It is expected that the cisternostomy technique 3 can be considered as an adjuvant surgical strategy for severe TBI effective in reducing ICP with good GOS and a low rate of complications in the postoperative period following cisternostomy, decreased number of days on a ventilator and ICU stay with good GOS at 6 months. Performing a cisternostomy demands specific instruments and expertise in skull base and vascular surgery, making its widespread use in trauma care centers challenging. Data will be collected and analyzed by using the SPSS 24 version. Quantitative variables such as age and demographic variables will be described as Mean +/- SD for both groups. Comparison of both groups for the surgical outcome will be done by using the Chi-square test and t-test according to the nature of outcome variables. The P-value of equal or less than 0.05 will be considered significant.