CSF Leak

The key points that need to be observed in order to prevent complications involving leakage of cere-brospinal fluid (CSF) are:

Halo Sign Csf Leak

Fig. 12.11 a A proptosed eye due to retro-orbital bleeding. b A CT scan of a patient who had bleeding into the left posterior

Fig. 12.11 a A proptosed eye due to retro-orbital bleeding. b A CT scan of a patient who had bleeding into the left posterior compartment of the eye that was not decompressed and resulted in blindness.

Congenital Csf Leak
Fig. 12.12 a, b A patient who had left enophthalmos, ptosis, and a dilated pupil without blindness due to excessive removal

of bone that included the floor of the orbit and damage to the oculomotor nerve. c, d Radiology showing the result of surgery.

Radiology Step Defect

Fig. 12.13 a A transilluminated skull showing the thin bone of the anterior skull base. b A coronal CT scan showing pneumo-cephalus because the skull base has been traversed. c An endo-scopic view of the defect.

Fig. 12.13 a A transilluminated skull showing the thin bone of the anterior skull base. b A coronal CT scan showing pneumo-cephalus because the skull base has been traversed. c An endo-scopic view of the defect.

• Follow the preoperative checklist.

• Do not fiddle around the attachment of the middle turbinate to the roof of the anterior skull base unless you are familiar with this area.

• It is safest to open the posterior ethmoid air cells once you have found the height of the roof of the sphenoid sinus: if you stay below this level you will not go through the skull base.

• Do not angle your instruments medially toward the lateral lamella as the skull base is extremely thin in this area and you are more prone to cause a leak.

The thinnest area of the skull base is adjacent to where the anterior ethmoid artery enters the anterior skull base at the lateral lamella of the cribriform plate (Fig. 12.13 a-c). The next most common area where CSF leakage occurs is where the middle third of the middle turbinate starts to attach more laterally from the skull base to the lateral nasal wall. It is here that it can inadvertently be grasped, twisted, or pulled and a defect created. The skull base tends to angle inferiorly as the surgeon works posteriorly, and the height of the posterior ethmoid sinuses varies. You need to have a good reason to be in the posterior ethmoid sinuses. This reason is often that there is severe polyposis with or without purulent disease.

The CT scan can help the surgeon decide the extent of surgery that is likely to be needed to remove dis eased mucosa and aerate the affected sinus. (NB Be careful if the CT scan was done during or shortly after a course of oral steroids as this can appreciably reduce the amount of mucosal swelling and the retention of secretions.) See whether there is a "black halo" of some air in the peripheral cells around the skull base (Fig. 12.14a, b). This is an encouraging sign as it means that there is a cushion of normal cells that will be entered before reaching the skull base. A "white-out" on CT needs to be approached with more caution. First, it is worth judging the height of the posterior ethmoid sinuses on CT by examining the height from the posterior skull base to the roof of the maxillary sinuses on the posterior coronal cuts. Next, the surgeon should check for the presence of a sphenoethmoid air cell. Before starting any surgery it is worth flexing the head on the neck as this will place the skull base in a more vertical plane. This is particularly worthwhile as, following intubation, the patient is often positioned on the operating table with the head extended, making it more likely that the surgeon will enter the skull base if they go straight backward.

If there is a "white-out," one safe strategy is to enter the sphenoid sinus before the posterior ethmoid sinuses have been opened to find the height of its roof. As the roof of the ethmoid sinuses is never lower than the roof of the sphenoid sinus, this is a useful indicator of the level below which it is safe to operate. While the

Csf Leak Ethmoid Sinus
Fig. 12.14 a A "black halo" of air on a CT scan showing that the surgeon will come across aerated cells before the skull base. b A "white-out" with no aeration of the sinuses.
Csf Leak Pics
Fig. 12.15 CSF coming out of a defect in the posterior wall of the sphenoid sinus.

posterior ethmoid sinuses can be higher than the roof of the sphenoid sinus, these cells are few and usually large, and just by opening them below the level of the roof of the sphenoid sinus it will become apparent where they are. A curved-ended sound, for example, the olive-shaped end of a curved sucker, can be used to feel whether there is a space behind any of the bony partitions so that these can be removed with through-cutting forceps or a Hajek punch.

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Essentials of Human Physiology

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Responses

  • Joefess
    Hi I had a CT Scan of my Sinus done two weeks ago due to major head pain, the doctor who had done the surgery stated I had PTSD? So on the CT report it stated exactly this...<br /><br />Evidence of previous sinus microsurgery with operative defect in the medial wall of each maxillary sinus and throughout the ethmoid air cells. there is inflammatory mucosal thickening in the bilateral frontal, sphenoid and right maxillary sinuses.<br /><br />I have right side blurred vision @ times when I try to read, I have had pain in my head like never before. I went into the surgery due to a chronic sinus infection, when I only had allergies before. Send a note if I need to explain better. or tell me if I send the scan if you can read it / them because I had alot of scans due to this issue...
    8 years ago

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