Neurosurg Focus 9 (1):Article 7, 2000, Click here to return to Table of Contents Surgical treatment of spontaneous spinal cerebrospinal fluid leaks CORMAC O. MAHER, M.D., FREDRIC B. MEYER, M.D., AND BAHRAM MOKRI, M.D. Departments of Neurosurgery and Neurology, Mayo Clinic, Rochester, Minnesota Spontaneous spinal cerebrospinal fluid (CSF) leaks are an increasingly recognized cause of intracranial hypoten- sion. In this report the authors review the indications for surgery, surgical techniques, and surgery-related outcomes for these lesions. The major presenting symptoms include postural headaches, nausea, vomiting, and diplopia. Often, there is no history of traumatic injury. The most common cranial magnetic resonance (MR) imaging features include pachymeningeal gadolinium enhancement and sagging of the brain. On spinal MR images, diverticula are frequently noted. In cases in which symptoms are severe and refractory to less invasive measures, surgical intervention is indi- cated. Tears in the dura or leaking diverticula that are identified as the sources of the CSF leak often can be ligated or repaired. When a source of CSF egress is not found intraoperatively, packing the epidural space with blood-soaked Gelfoam or muscle at the appropriate level can lead to relief of symptoms. Occasionally the dural defect is large, irreg- ular, or has attenuated borders that may not be possible to repair with sutures. These may be repaired by packing the defect with muscle or blood-soaked Gelfoam. Indications for and outcomes of surgery in patients with this condition will become more defined as surgeons gain experience with these procedures. KEY WORDS • cerebrospinal fluid leak • intracranial hypotension • intracranial pressure The syndrome of low-pressure CSF headaches was bar puncture. In most patients low or unmeasurable CSF first recognized following diagnostic lumbar puncture. As pressures are observed; however, in a significant minority early as the 1930s, Schaltenbrand in Germany and Wolt- normal opening pressures will be demonstrated on serial man in the United States were familiar with “spontane- lumbar punctures.9,12 Increased levels of CSF protein con- ous” posture-related low-pressure headaches that did not centration and a lymphocytic pleocytosis are common.12 develop after lumbar puncture.23,31 The clinical presenta- On MR imaging examination of the head, although diffuse tion of low-pressure CSF headaches is well described.2,8,9, pachymeningeal enhancement is a very frequent finding, 17,20,24 The headache is typically provoked or exacerbated its absence does not exclude the diagnosis of CSF leak- when the patient is in an upright position and is relieved age.4,13,18,28 In some cases, pachymeningeal enhancement or markedly reduced by recumbency. In addition, the may resolve despite a continued symptomatic CSF leak.11 headaches are often associated with nausea, vomiting, "Sagging" of the brain, sometimes with enough descent of photophobia, diplopia due to a uni- or bilateral sixth cra- the cerebellar tonsils to appear as an acquired Chiari I nial nerve palsy, and tinnitus. In spontaneous CSF leaks, malformation, and subdural fluid collections, usually thin there is sometimes a history of strenuous activity or trivial and bilateral, are observed in many patients.1,16,18,19 In most traumatic injury. Occasionally, patients may complain of cases, these MR imaging findings are resolved following back or neck pain that may or may not correspond to the 25 a successful repair of the CSF leak. Leptomeningeal en- level of the CSF leak. Many patients experience a spon- hancement is not a feature of this condition, and, if pre- taneous resolution of symptoms. In cases in which the sent, alternative diagnoses should be considered. syndrome is untreated for an extended period and does not The location of the CSF leak should be demonstrated by resolve, the headache may evolve into a chronic daily radioisotope cisternography, myelography, CT myelo- headache and lose much of the characteristic posture-re- gram, or MR imaging examination of the spine in all pa- lated features.10,14,15 tients for whom surgical repair of the CSF leak is consid- ered (Fig. 1).5,30 Indium-111 radioisotope cisternography DIAGNOSIS is helpful but CT myelography is the most sensitive diag- nostic modality for establishing the presence of a CSF In patients with a characteristic history, the diagnosis 15 may be confirmed by obtaining head MR images or lum- leak. If an initial myelogram demonstrates normal find- ings, repeating the study several weeks later may be use- ful.10 Magnetic resonance imaging examination of the Abbreviations used in this paper: CSF = cerebrospinal fluid; spine may be used preoperatively to identify structural ab- CT = computerized tomography; MR = magnetic resonance. normalities in patients with known leaks (Fig. 2). Fur- Neurosurg. Focus / Volume 9 / July, 2000 1 Unauthenticated | Downloaded 09/26/21 01:10 PM UTC C. Maher, F. Meyer, and B. Mokri Fig. 2. Magnetic resonance cisternography. Sagittal (left) and parasagittal (right) views revealing an abnormal signal consistent with a CSF leak in the region of T-10 on the right. source of CSF egress. If the diverticulum does not sur- round a nerve root, it may be easily ligated. If the diver- ticulum does surround a nonessential nerve root, however, it must be ligated around the nerve. At nerve roots sup- plying the extremities, special care must be taken to pre- Fig. 1. Standard myelogram (anteroposterior view) obtained in serve nerve root function. For this reason, plication of the a patient with a spontaneous spinal CSF leak. dura surrounding the nerve root may be a good alternative to ligation at these levels. Because the diverticulum may not be the source of the CSF leak, the dura in proximity to thermore, spine MR imaging or radioisotope cisternogra- the leak should be carefully explored under the operating phy may help identify the approximate level of the leak, microscope to rule out the presence of multiple sites of which can then be better defined by CT myelography in CSF egress.10 Even in cases in which a diverticulum is lo- which multiple thin sections are obtained at the suspected cated and repaired, it is necessary to pack the surrounding level (Fig. 3). Diverticula are not uncommon and, when epidural space with muscle or blood-soaked Gelfoam. present, should not automatically be identified as the If a diverticulum is not visualized on preoperative neu- source of the CSF leak. roimaging, the level of CSF leak is explored. The thecal Treatment sac and proximal nerve roots should be carefully exposed. If a diverticulum is discovered intraoperatively, this may Some cases of spontaneous spinal CSF leak will resolve be ligated and then packed with muscle or Gelfoam. More without any treatment. Therefore, surgery is rarely indi- often, no diverticulum is identified if none was visualized cated for symptoms that have been present for a short on the preoperative neuroimaging studies.26 In these cases, duration. In general, an epidural blood patch procedure the epidural space surrounding the nerve roots as they exit should be attempted at least once.22 Epidural blood patch- the thecal sac should be packed with blood-soaked Gel- es are usually effective when directed at the appropriate foam or muscle. level; however, symptoms will frequently recur after a few days. If the symptoms do recur, it is reasonable to offer patients one or more epidural blood patch procedures prior to considering surgical repair. Some patients have been treated with epidural saline infusion7,21,29 or epidural injection of fibrin glue.3,6 The results of these treatments are unpredictable and often not long lasting. Experience with fibrin glue is limited in this setting. SURGICAL TECHNIQUE A standard hemilaminectomy is performed at the level of the CSF leak as directed by the preoperative neuro- imaging findings. Adequate exposure usually requires at least a complete hemilaminectomy at a single level, al- though multilevel exposures are not uncommon. In cases in which preoperative neuroimaging studies demonstrate more than one CSF leak at nonadjacent levels, it may be enough to repair the larger of the tears. The bone removal should be extended far enough laterally to allow for care- Fig. 3. Computerized tomography myelography demonstrating ful exploration of the dura in proximity to the nerve roots. a large meningeal diverticulum on the right. Extraarachnoid con- Diverticula are frequently observed on neuroimaging as a trast surrounds the thecal sac. 2 Neurosurg. Focus / Volume 9 / July, 2000 Unauthenticated | Downloaded 09/26/21 01:10 PM UTC Spontaneous CSF leaks SURGICAL OUTCOMES 11. Mokri B, Atkinson JLD, Dodick DW, et al: Absent pachy- meningeal gadolinium enhancement on cranial MRI despite 27 Schievink, et al., have reported on 10 patients who un- symptomatic CSF leak. Neurology 53:402–404, 1999 derwent surgery for the treatment of spontaneous spinal 12. Mokri B, Hunter SF, Atkinson JLD, et al: Orthostatic headaches CSF leaks. In six of these patients (60%), no leak was caused by CSF leak but with normal CSF pressures. Neurology found. In seven patients (70%) the defect was packed with 51:786–790, 1998 muscle or Gelfoam, and in three the diverticula were lig- 13. Mokri B, Krueger BR, Miller GM, et al: Meningeal gadolinium ated. All patients experienced complete relief of their enhancement in low-pressure headaches. J Neuroimaging 3: headaches, as well as the associated nausea and vomiting, 11–15, 1993 postoperatively and at a mean follow-up period of 19 14. Mokri B, Parisi JE, Scheithauer BW, et al: Meningeal biopsy in intracranial hypotension: meningeal enhancement on MRI. months. There were two reported complications in that Neurology 45:1801–1807, 1995 series: one patient suffered a transient symptomatic in- 15. Mokri B, Piepgras DG, Miller GM: Syndrome of orthostatic crease in intracranial pressure and another experienced leg headaches and diffuse pachymeningeal gadolinium enhance- numbness that was thought to be caused by the placement ment.