Management of Postoperative Cerebrospinal Fluid Leak

Technique

The dressing is applied in a manner similar to the initial postoperative dressing. First, a vertical gathering tie is placed in the temporal fossa. Dressing sponges (4×4) are folded in half and placed directly over the surgical site and in the postauricular sulcus to support the auricle ( Fig. 55.1A ). Next, fluffed Kerlix is placed over the 4×4 sponges and the auricle ( Fig. 55.1B ). A tight wrap of roller gauze is applied ( Fig. 55.1C ). The direction of the wrap should be from the ear toward the occiput, which ensures that the auricle is not damaged by anterior folding. In addition, the vertical tie must be as lateral as possible in the temporal fossa to avoid a pressure point on the forehead. Pressure necrosis of the forehead skin can develop easily if attention is not given to this point.

The last layer of this dressing is a 3-inch (7.62-cm) elastic bandage, which provides the final compression ( Fig. 55.1D ). The elastic bandage should be wrapped firmly, but patient comfort must be accommodated. Usually, the last several turns can be altered to adjust the exact amount of compression. Ideally, a pressure dressing should be left in place for 3 to 5 days, which allows time for healing of the CSF leak site to occur. A minimum of 48 hours without leakage must pass before the dressing is removed.

In addition to the pressure dressing, other conservative actions should be undertaken. All these measures are directed at decreasing CSF pressure. Straining (Valsalva maneuver) is strictly avoided and the patient is kept at bed rest with the head elevated 45 degrees. Limited activity, such as bathroom privileges or brief periods of sitting up in a chair, is at the surgeon’s discretion. Stool softeners and cough suppressants can be used. Acetazolamide (Diamox) may be administered to decrease CSF production.

Technique

To place the catheter, a lumbar puncture is performed at the L4–L5 level. The patient is placed in either a sitting or lateral decubitus position. The spinous processes are palpated and L4–L5 is identified at the level of the iliac crest. The patient is asked to flex the back and bring the knees and chin to the chest. A prepared catheter kit contains all the necessary supplies for preparing, draping, and anesthetizing the site. A 14-gauge Tuohy needle is introduced in the midline with a slightly superior angle to traverse the space between the spinous processes ( Fig. 55.2 ). The obturator is removed at intervals so that the surgeon can look for a flow of CSF. When a good flow of CSF is established, the epidural catheter is introduced through the needle and threaded into the epidural space. The opened side of the bevel of the needle faces the patient’s left or right side on penetrating the spinous ligaments and arachnoid. Before the catheter is threaded, the bevel is turned to open superiorly, facilitating directing the catheter cephalad. With a flow of CSF established, the needle is withdrawn, and the connector is placed on the end of the catheter so that a connection to intravenous tubing can be made. An empty intravenous fluid bag is attached to the tubing, and all connections are secured with tape ( Fig. 55.3A ).

Several methods of regulating CSF output exist. This regulation is important because tension pneumocephalus and brain herniation can occur if CSF is removed too rapidly. Alternatively, if an inadequate amount of CSF is removed, the purpose of the drain is defeated. Humans produce approximately 18 mL of CSF per hour. The natural mechanisms of CSF absorption reduce some CSF; the lumbar drain should remove less than 18 mL of CSF per hour. The common neurosurgical practice is to order 50 mL of CSF removed every 8 hours.

Gravity is the standard method of effecting CSF drainage. The collection bag is placed at the level of the patient’s heart or below to create increasing output of CSF as needed. This method requires extremely attentive nursing care to ensure the proper amount of drainage. Drains placed to respond to gravity have highly variable output, and a change in patient position may significantly increase or decrease the flow. Establishing an even flow of CSF is difficult, and a bolus of fluid is usually removed, after which the drain is clamped. A limiting device, such as the LimiTorr volume limiting CSF drainage system (Integra LifeSciences), may be employed to halt drainage at a predetermined volume (i.e., 30 mL). The drainage system is at risk of occluding and, subsequently, removing the amount of CSF ordered becomes difficult.

While the lumbar drain is in place, the patient must be closely observed for signs of infection. The temperature, surgical wound, lumbar drain site, and white blood cell count must be monitored. Samples of CSF may be examined at any time. Headache during CSF drainage is common, but meningismus should not be present. Prophylactic antibiotics are controversial but are administered by some surgeons. As with a pressure dressing, the lumbar drain should be left in place for 4 or 5 days. We often clamp the drain for the last 24 hours so that the drainage can be resumed if the leak recurs.