Physio Network: CSF Leaks

Updated: Feb 7

The following blog was originally published by Physio Network. It's great to have the support of organisations like Physio Network, keen to educate physios about rarer conditions that may affect their patients as well as the more common.

With the increasing recognition of spontaneous spinal cerebrospinal fluid (CSF) leaks, you just may find yourself with a patient presenting for rehab after procedures to treat this condition. Unfortunately, you may also find a patient on your list who hasn’t yet been diagnosed but is in fact experiencing the consequences of a spontaneous spinal CSF leak and your recognition of this issue could make an enormous difference to the patient. So what is it and what can you do to help?

Symptoms arising from a leak of CSF after a dural puncture have been recognised since the 1st lumbar punctures performed in the late 19th century. In the past few decades, spontaneous leaks due to dural defects have been increasingly recognised as imaging has allowed visualisation of leaks and the changes they cause in the CNS due to the induced Spontaneous Intracranial Hypotension (SIH) (1). The term “spontaneous” leak is actually used to describe those not occurring due to iatrogenic effects of a medical procedure which can include those occurring after trauma or with no known precipitant. Leaks have been recognised to occur from meningeal diverticula, discrete tears (sometimes associated with bony spurs) or venous fistulas directly draining CSF into the venous system (2).

CT Myelogram and intraoperative photos of the same patient with a dural tear due to a bone spur. Supplied by Dr Scott Davies.

Symptoms and Diagnosis

The most recent estimate is an average annual incidence of this condition of 3.7 per 100 000 population (4.3 per 100 000 and for women and 2.9 per 100 000 for men) (3). Diagnosis is frequently delayed, primarily due to lack of recognition of this condition and a high false negative rate on any single diagnostic test. In 2003, the average duration of symptoms for a patient with a spinal CSF leak in a US study was 13 months before diagnosis (4). A small Australian study in 2019 reported an average 2.7 year delay to diagnosis (5).

Spontaneous spinal CSF leaks are believed to cause symptoms via a number of mechanisms related to the loss of CSF especially from the cranium. As a result, the usual functions of CSF such as buoyancy, cushioning, nutrition and waste clearance are impaired. The buoyancy attributed to CSF usually reduces the apparent weight of the brain from 1500 g to 50g. Loss of this effect can result in descent of brain structures particularly in the upright position and traction on the pain sensitive meninges. Loss of CSF volume is also believed to trigger compensatory increases in blood volume leading to venous distension which may trigger nociceptive responses as well as impacting more generally on vascular flow. The loss of CSF volume may also leave cranial structures including brain, pituitary and cranial nerves susceptible to mechanical effects normally cushioned by the fluid, as well as restriction of the normal flow of CSF around the foramen magnum due to the descent of the brain which sometimes mimicks a Chiari malformation (2, 6).

Not surprisingly, the classic symptom of the spinal CSF leak is headache, typically worse when upright and better on lying down. It is usually bilateral and diffuse but may localise, most commonly to the occiput. The headache may be instantaneous on standing, develop over minutes to hours, or may be described as a “second half of the day headache”(2). It is important to recognise, however, that this classic pattern of headache often becomes less distinct with greater chronicity (6). In addition to the headache, patients with spinal CSF leaks commonly report pain in the cervical and thoracic region along with a wide range of neurological symptoms (as described in Table 1).

Non-physio Management

Conservative measures such as bedrest, increased fluids and caffeine can sometimes lead to spontaneous healing. When this fails there are a number of procedures which can be used in an attempt to seal the site of CSF leak. Commonly an epidural blood patch is used in which the patient’s own blood is injected into the epidural space in an attempt to “plug” the leak site.

In comparison to leaks occurring from a lumbar puncture, larger volumes of blood (commonly 20 to 30 ml) are used and multiple patches may be required to achieve full resolution of leaking. These patches may be applied directly to the leak site if it has been successfully identified on imaging, or carried out “blind” often at the upper lumbar level, sometimes with head down tilting of the patient to encourage the spread of the blood as far as possible through the spinal column in the hope that it will reach a remote leak site.

When a leak site is known, fibrin glue can also be directly applied to the dural defect. A range of different surgical repairs may also be undertaken where the leak can be located but is not responsive to blood patching, and recently CSF venous fistulas have been successfully treated by embolisation procedures (13).

Physio management

There is little currently in the peer-reviewed literature to direct physiotherapy care of patients with spinal CSF leaks and clearly much research still to be done. This leaves us to apply the basic science and models from related conditions together with solid clinical reasoning in order to best help these patients.

As with any patient recovering from a tissue injury or surgery, protection of the healing site is one of the first principles. As yet there is little data on the specific timeframes of dural healing after these procedures or the mechanical and inflammatory impacts on the dura, spinal cord and surrounding tissues of the various repair procedures, so careful assumptions must be made based on other tissue healing models.

Factors believed to substantially increase mechanical load on the dura, and therefore potentially put a repair site at risk, include body movements generating tension in the dura. The dura is structurally more susceptible to transversely applied tension (such as during upper limb neurodynamic testing procedures, and spinal lateral flexion) than to tension applied axially (such as during spinal flexion or straight leg raise) (14). Spinal rotation may physically stress the dura, and the presence of impaired segmental control at any level of the spine may also presumably lead to increased mechanical strain on the dura, as persistent rotation of one spinal segment relative to the next has been shown to impart significant stretch to nerve roots (14). Valsalva-type manoeuvres may stress the dura by increasing CSF pressure (such as during lifting or straining to empty the bowels) (15). These forces will all need to be controlled appropriate to the stage of recovery to protect the repair site and facilitate optimal tissue repair.

Body position relative to gravity will impact the position of the cord and dura within the canal, and its relationship to adjacent structures. For example, in neutral spinal positions the cord will generally move within the canal under the influence of gravity, dropping against the lower side of the canal. Spinal flexion against gravity, however, can lift the cord and dura off the lower surface of the canal (14). Combinations of trunk flexion/extension and body position relative to gravity can therefore presumably impact the mechanics of cord and dura relative to surrounding tissue interfaces during functional and therapeutic movements, and sensible manipulation of these variables may facilitate therapeutic processes (14).

As the neural tract is mechanically linked throughout the body, compromises of neural mobility in body areas remote from the CSF leak site may presumably also impact dural mechanics and function in the spinal and cranial regions as is witnessed in multiple crush syndrome (16). Management of remote mechanical neural restrictions and optimisation of the mechanics of the entire neural tract may therefore improve the longevity of the CSF leak repair and overall recovery of function.

Optimal recovery after treatment for a CSF leak will require consideration of the secondary implications of the often-delayed diagnosis and repair. Patients may have experienced significant levels of pain over an extended period and therefore experience central neurological changes related to the ongoing pain input. In addition, many patients will experience repeated recurrence of the leak after an apparently successful patch, making them aware and understandably potentially fearful of the real risk of ‘re-leaking’. Significant deconditioning will also be a reality for many patients who have been severely limited in their ability to function in upright postures prior to treatment.

The body’s own attempts to compensate for the leak of CSF can further contribute to symptoms after repair. For example, CSF production is thought to increase in an attempt to compensate for the leak and this may contribute to “rebound intracranial hypertension” after successful sealing of a CSF leak (6). This reversal of intracranial pressure to a higher than normal level after sealing of a CSF leak can cause reversal of the patient’s orthostatic pattern to intolerance of lying down. The raised CSF pressure may also theoretically put the repair site at risk as well as other potential complications so should be brought to the attention of the treating specialist.

The results of a recent study of CSF dynamics in patients with leaks led the authors to propose that some patients with spinal CSF leaks may develop scarring, fibrosis or adhesions between the meninges and surrounding tissues which could clearly have significant implications for the mechanical function of the spinal dura (17). This hypothesis is supported by the results of epidurograms performed after blood patching of iatrogenic leaks (18).

CFS Leaks and Connective Tissue Disorders

A significant proportion of patients with spontaneous spinal CSF leaks have an underlying inherited disorder of connective tissue or hypermobility syndrome (e.g. Marfans Syndrome or Ehlers-Danlos Syndrome) (19). Patients with these conditions often experience impaired tissue healing, impaired proprioception, and a range of comorbidities including small fibre neuropathies, autonomic dysfunction (including orthostatic intolerance), and disorders involving gastrointestinal, genitourinary and immune systems. In addition, these patients’ neural systems may need to mechanically adapt to significantly greater ranges of motion compared to a client of average mobility (20). These factors will be significant considerations in determining the progression of rehabilitation for a CSF leak patient with a hypermobility syndrome.

Wrapping Up

There are clearly many unanswered clinical questions around best practices in the management of patients who have experienced spontaneous spinal CSF leaks. Research in the field will likely see a growing knowledge base to better inform our practices in the coming years. In the meantime, physios able to apply their existing knowledge and clinical reasoning with respect for the individual patient and the many complex factors affecting their recovery process, can potentially have a significant positive effect on the function and quality of life of their patient.


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