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.



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

Correct positioning is key for a smooth and uncomplicated operative procedure.

Important to keep in mind: in prone position a free-hanging abdomen is mandatory to prevent venous congestion of the operative field.

Inadequate positioning can lead to increased blood loss associated with the higher IAP values.

A rise in blood loss will obscure the visual operating field, making microsurgery a more difficult procedure.

A rise in IAP can cause venous congestion, an increased intrathoracic pressure, intracranial hypertension in patients with morbid obesity or brain swelling during posterior fossa surgery or supratentorial craniotomy in the prone position.


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.

Expected studies about IAP

Dr. van Eijs, anesthesiologist at ETZ Tilburg has submitted an application to the MEC (Medical Review Ethics Committee) for a study to measure the IAP when using the IPS-system. The IPS (Inflatable Prone Support) allows for the optimal positioning of patients on air and is designed and produced by Ergotrics. The objective is to assess the difference in Intra-Abdominal Pressure (IAP) relative to the current way of prone positioning. It is measured via a urinary catheter, when the patient is in prone position.

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