CSF Otorrhea Treatment & Management

Updated: Jun 16, 2020
  • Author: Matthew B Hanson, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Treatment

Medical Therapy

Although the presence of a CSF leak places the patient at risk for meningitis, the use of prophylactic antibiotics is controversial. Many believe the use of antibiotics in the absence of infection has the effect of selecting out resistant organisms among the normal flora, complicating the treatment of meningitis when it does arise. They believe antibiotics should be withheld unless signs and symptoms of meningitis occur and diagnosis is confirmed by spinal tap. Then, broad-spectrum antibiotics are instituted until cultures and sensitivities are returned.

Others believe that the routine use of prophylactic broad-spectrum antibiotics is advised in CSF otorrhea. The initial signs of meningitis may be subtle, and irreparable harm may occur to the CNS by the time obvious meningitic signs are present. A number of published studies have shown that the risk of meningitis is significantly reduced when prophylactic antibiotics are used in posttraumatic CSF leakage, and their use in this situation is generally recommended. However, the results of these studies can probably not be extrapolated to postoperative and spontaneous leaks.

Prophylactic antibiotics should always be used in patients who are immunosuppressed and when soilage of the central nervous system is obvious. In these situations, overwhelming infection may be present before signs of meningitis are noted. Antibiotics are also routinely used when an indwelling device, such as a lumbar or ventricular drain, is used.

Often, medication can be used to decrease production of spinal fluid. Such medications include diuretics (eg, furosemide, hydrochlorothiazide), carbonic anhydrase inhibitors (eg, acetazolamide), and steroids. These medications are not used as a primary therapy for a CSF leak, but they are valuable adjuncts to treatment. During the diagnosis and evaluation phase, they may hamper the ability to locate the leak if the output is low.

Otogenic CSF leak secondary to recent surgery or trauma can often be treated conservatively with a compressive dressing and bed rest with head elevation. Spinal fluid leaks following acoustic neuroma surgery respond to this treatment 80% of the time. This is also true of leaks associated with temporal bone fractures, which almost always seal in 3-4 weeks with this conservative therapy. [4]

Postoperative leakage though an incision line can often be stopped with a single well-placed mattress stitch.

Continuous lumbar spinal fluid drainage may serve as a useful adjunct to the conservative treatment of a spinal fluid leak related to surgery or trauma. Continuous drainage of spinal fluid serves to decrease the pressure head against the leak to allow natural healing to occur. Do not use spinal drains when the site of leakage is not known because they may hamper localization and allow air to flow into the cranial vault, resulting in pneumocephalus. In cases of spontaneous leakage, the lumbar drain may help facilitate healing after surgical repair.

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Surgical Therapy

Primary treatment of a spontaneous otogenic spinal fluid leak is surgical repair. In patients with postsurgical and traumatic leaks, surgery is reserved for those in whom conservative therapy is unsuccessful. Surgical approach is dictated by the nature and location of the defect.

Spontaneous leaks in children with otic capsule defects, such as Mondini deformity, can often be repaired by a transcanal approach. Because rarely any hearing is present, a stapedectomy is usually performed and the oval window obliterated with soft tissue. A transcanal approach can also be used in some cases of CSF leakage due to a patent Hyrtl fissure.

However, in most cases of spontaneous leakage, a transmastoid approach is preferred. [5] This is especially true if the exact site of the leakage is not known or suggested on imaging studies. The exposure of a mastoidectomy usually allows excellent visualization of the leakage site. The site can often be repaired with a small amount of fascia supported by Gelfoam. If the leak is related to a small ( < 1 cm) defect in the bone of the tegmen, the fascial repair can be supported with a tragal cartilage graft placed between the intact bony edges and the dura.

Occasionally, a fat or muscle graft may be needed. In rare cases, the exact site of leakage is not found, and diffuse leak is observed from multiple mastoid air-cell tracts. In this situation, the mastoid may need to be obliterated with fat. Obliteration of the middle ear and eustachian tube may also be required, especially if the leakage is not limited to the mastoid.

A study by Kim et al supported the efficacy of transmastoid procedures for patients with spontaneous temporal bone CSF leaks. In the study, 15 patients (16 ears) with temporal bone ̶ related chronic otorrhea and conductive/mixed hearing loss underwent transmastoid surgery. The procedures were multilayered, with autologous mastoid bone, temporalis fascia, and tissue sealant typically employed. The operations were successful in all but one ear, which was subsequently treated with a middle fossa craniotomy. None of the patients suffered serious complications, and the air-bone gap, which had a mean preoperative value of 19 dB, was 12 dB or less following surgery in the 14 patients for whom postoperative audiograms were available. [14]

Leaks may occur in ears that have previously undergone canal wall down mastoidectomy. Removal of the canal wall may also be dictated by the extent of disease when the leak is associated with an active cholesteatoma. In these situations, the external ear and mastoid epithelium must be completely removed and the ear canal sewn over. Abdominal fat is then used for obliteration.

Leaks occurring from defects of the posterior cranial fossa anterior to the sigmoid sinus present a special problem. This is the area of the basal cistern, where no arachnoid mesh is present. Leakage from this area is explosive and profuse and is not well controlled with fascia alone. A large fat graft obliterating the mastoid is usually required.

If a leak is due to a large (>1 cm) defect in the floor of the middle fossa, the problem is best addressed with a combined middle fossa/transmastoid approach. A mastoidectomy is performed first to identify the site of leakage. Do not attempt to reduce herniated brain tissue. Such encephaloceles do not contain functioning brain tissue and should be excised using bipolar cautery. Once the defect is identified, use the middle fossa approach for repair. The middle fossa affords excellent visualization of the defect and an opportunity to use the intact bony edges of the defect to hold any repair material in place.

Recommended repair of such large defects is with a 3-layer technique. A layer of calvarial bone is sandwiched between 2 layers of fascia. Use of a bone graft helps to resist the pulsation of the CSF and prevent formation of a new meningocele. The calvarial bone can be harvested by splitting the bone flap taken for the craniotomy. [15] Fibrin glue is a very useful adjunct to such a repair and helps seal the components in place.

Fascia for grafting is usually harvested from the temporalis muscle. This muscle can also serve as the source of a muscle graft. If a vascularized pedicled flap is desired, this can be harvested from the superficial temporal fascia.

If adequate grafting material is not readily available in the operative wound, it may need to be harvested from elsewhere in the body. One such site is the fascia lata found on the lateral thigh. This site is capable of providing large amounts of fascia for dural repair.

Several local vascularized flaps are available to be used for reconstruction in the repair of a CSF leak. These flaps include temporalis muscle, galeal flaps, and superficial temporoparietal fascia. These flaps are especially useful following skull base surgery, where large dural defects are often created. In rare cases of very large defects, a vascularized free flap may be required.

Several forms of commercially available materials are now available to assist in the repair of a CSF leak. One such material is made from bovine pericardium. This material is very tough, but it is pliable and easy to work with. Hydroxyapatite cement may also be used to aid in reconstruction of bone defects. Fibrin glue alone cannot be used as a repair material, but it can be used to secure the repair components. Each of these substances is biocompatible and becomes integrated with host tissue. Other synthetic materials, such as silicone sheeting, Marlex mesh, titanium plates, and methylmethacrylate, do not become integrated with host tissue and have a high rate of infection or extrusion. The author prefers that even biocompatible materials not be used if the supply of the patient's own tissue is adequate.

Continuous lumbar spinal fluid drainage is an important adjunct to surgical repair of otogenic CSF leakage. The drain is usually placed at the beginning of treatment, but it should be left clamped until the leakage site is identified. After the surgery, remove a small amount of spinal fluid on an hourly basis to decrease the pressure head against the repair. Care must be taken not to remove too much spinal fluid because this may draw air into the cranium through the repair, resulting in pneumocephalus. The patient must remain on bed rest as long as the drain is in place.

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Postoperative Details

In most cases, the postoperative patient should be observed in an ICU setting. The intensive care setting ensures that neurologic changes heralding an arising complication will be rapidly noticed and addressed. Perform hourly neurologic checks for the first 24 hours after surgery and then every 2 hours until the patient is well enough to leave the unit.

An important aspect of ICU care is monitoring of the lumbar drain. Drainage should be accomplished by draining a specific amount every hour, usually about 10 mL. Occasionally, this causes severe headache, in which case a smaller amount can be removed or the fluid can be removed less frequently (eg, 5 mL every half hour). Some have advocated leaving the drain open at a level just below the level of the leak, allowing the spinal fluid to drain at its own pace while maintaining a low pressure against the repair. This technique has led to some reports of pneumocephalus and is generally not recommended. Others have suggested attaching the drain to an IV pump so that a steady even flow can be maintained. This, too, may be risky because it may cause too much drainage and result in pneumocephalus.

While the drain is in place, patients should remain on bed rest. Use position changes and compression boots to prevent bedsores and deep venous thrombosis.

Check spinal fluid drainage every 2 days with a Gram stain and a culture.

The lumbar drain is usually left in place for 2-3 days postoperatively. If no sign of leakage is present, it is clamped and the patient is observed for an additional 24 hours. If no further leakage is observed, the drain is then removed.

In many cases of surgical repair of a CSF leak, ICU monitoring may not even be necessary. These include cases treated by a transcanal approach that do not require lumbar drainage.

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Complications

The risks faced by patients undergoing surgery to repair a CSF leak are far less than those they face if the leak remains unaddressed. Although some leaks may continue in some patients for prolonged periods, any leak is likely to eventually result in meningitis if monitored for long enough. The surgical risks associated with the surgery are no greater than those for any other similar neurologic surgery.

Neurologic surgery carries risks for intracranial bleeding, cerebral edema, hydrocephalus, stroke, and of course, meningitis. Any change in mental status in the postoperative period must be rapidly evaluated and addressed. An immediate CT scan of the brain performed without contrast usually demonstrates any bleeding, edema, stroke, or hydrocephalus. If the findings of this study are normal, it should be followed by a lumbar puncture. Lumbar puncture should not be performed before these entities are ruled out because removal of spinal fluid may result in brain herniation. However, in most situations, a lumbar drain is already in place. When mental status changes occur, the drain should be clamped until the CT scan findings are shown to be normal. A sample of the fluid in the reservoir can be sent off at any time.

A study by Stevens et al indicated that in patients with spontaneous CSF otorrhea who undergo surgical treatment, those with a thin tegmen (< 0.9 mm thick) tend to have a higher incidence and rate of adverse perioperative outcomes. The study involved 30 patients with thin tegmens and 15 patients with thicker tegmens, with leak recurrence more common in the thinner-tegmen group. [16]

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