The significance of intra-abdominal pressure in neurosurgery and neurological diseases: a narrative review and a conceptual proposal
Intra-abdominal pressure (IAP) is defined as the steady-state pressure within the abdominal cavity. The IAP is an important physiological parameter during neurosurgical procedures (spine and brain) in the prone position. The incidence of complications arising from increased IAP, known as intra-abdominal hypertension (IAH) or abdominal compartment syndrome in critically ill patients, can be high and its impact can be significant. In this review, we summarize how IAP impacts the cerebrospinal venous system and the jugular venous system via two pathways.
Increased intra-abdominal pressure (IAP) is recognized as a significant contributor to organ dysfunction in many critically ill patients. Intra-abdominal pressure (IAP) is defined as the steady-state pressure within the abdominal cavity. Under physiological conditions, values of up to 5 mmHg are considered normal in adults. However, in conditions such as obesity or pregnancy, basic IAP may range from 10 to 15 mmHg.
Fig 1. The concept of the two pathways. In the first pathway, an increase in IAP can cause backflow through the sacral venous plexus and the vertebral venous into the spinal canal. This can cause congestion of venous blood in the spinal canal and can cause flow of venous blood into the brain. In the second pathway, an increase in IAP can cause an increase in ITP (intrathoracic pressure) which in turn results in a back pressure on the jugular veins and decreases the drainage of the CSF (Cerebrospinal fluid) and the venous blood.
Implications for neurosurgical procedures
Evidence suggests that increased IAP may play an important role during neurosurgical procedures, in patients suffering from Idiopathic intracranial hypertension (IIH) or, in Traumatic Brain Injury (TBI) and during hydrocephalus therapy.
IAP measurement could provide relevant information to improve the safety of surgical procedures in spine surgery and posterior fossa surgery.
Measurement could optimize the treatment for Idiopathic intracranial hypertension (IIH), Traumatic Brain Injury (TBI), and hydrocephalus. However, more prospective research in this field is needed.