Conditions: Intracranial Injury from Sinus Surgery

What is a Intracranial injury?

The space occupied by the brain, the cranial vault, is separated from the sinuses by a thin layer of bone. Put another way, the ceiling of the sinuses is the floor of the cranial vault. Inadvertent injury to tissues beyond this partition can occur during sinus surgery. While this is a rare event, this page will explain some of the potential injuries ranging from minor to major.

Anatomy

The images below show a thin slice of the anatomy of a face from a CT scan, as if it were looking back at you. The colorized image on the right shows the relevant structures labelled. In green, the thin bone comprising the ethmoid sinuses is shown. Blue identifies bone to be preserved during sinus surgery. The first layer of tissue beyond this bone is the dura, which is a water-tight wrap surrounding the brain. The dura holds cerebrospinal fluid, within which the brain floats.

Anatomic Extent of Injuries

In sinus surgery, millimeters matter. Let’s walk through some scenarios of progressively worse injury to the cranial vault during removal of the ethmoid cells, shown in green above. If the bone (shown in blue) between the sinus and the cranial vault incurs a small fracture, there may be no consequence, as it may heal within a few weeks of surgery. During that time, if one were to sneeze or blow the nose, air could be pushed into the cranial vault (pneumocephalus). If the dura were to tear, then the cerebrospinal fluid (CSF) could leak into the sinuses. If a fracture is larger, then some of the brain tissue could herniate into the sinus (encephalocele). If the barrier between the non-sterile sinuses and the cranial vault were breached, there would be a risk of bacteria spreading to the cranial vault and causing an infection (such as meningitis or cerebritis). Going further, if a blood vessel within the cranial vault were to bleed, the spilled blood could accumulate (intracranial hematoma) and cause increased pressure on the brain. If a surgical instrument traversed the bone, dura, CSF space, then the instrument may contact and injure brain tissue.

HOw is Intracranial injury prevented?

Many factors go into maximizing safety during sinus surgery. The surgeon references the sinus CT scan prior to surgery to understand the individual variances present. Improved endoscopic visualization and technology and surgical experience and technique are key elements to minimizing risk in sinus surgery.

How is Intracranial injury identified?

Injury may become apparent during surgery, though some complications may manifest after surgery. If leakage of CSF is identified, the surgeon knows that the dura has a tear in it, and repair of this tear may be undertaken immediately. A CSF leak may, however, become apparent after surgery if a patient were to experience clear fluid dripping from the nose or, since CSF has a high salt content, noticing a distinctly salty taste. Bleeding in the cranial vault may cause headache, changes in the pupils of the eyes and decreased level of consciousness. Infection may be associated with headache, pain in the back of the neck (especially when lowering one’s chin or lifting a knee), nausea/vomiting, and intolerance to bright lights. While some pain after surgery and some sedation from anesthetic or pain medication is to be expected, any progressively of these symptoms, or any question about the appropriateness of a patient’s symptoms should be brought to medical attention. The time elapsed from symptoms to treatment, if needed, may influence final outcome—the sooner the better.

How is intracranial injury treated?

General guidelines for patients after sinus surgery involve avoidance of certain conditions. Nose blowing should not be done and sneezing, if unavoidable, should be done with an open mouth to release the pressure as freely as possible. High blood pressure may cause bleeding, so keeping blood pressure normal includes avoiding strenuous physical activity, enduring severe pain, and using one’s usual blood pressure medications, if applicable. Strenuous activity also increases CSF pressure, which might lead a small dural tear to leak and not heal. Placement of a lumbar drain may be undertaken to remove some of the CSF, preventing or minimizing leakage through the tear, so that the dura can heal faster. Bleeding within the cranial vault may be suspected based on symptoms and an examination by a physician, but definitive diagnosis typically requires an imaging study, such as a CT or MRI scan. Bleeding may need surgical treatment to stop the bleeding, relieve pressure on the brain to avoid development or progression of brain injury.