Indian Spine Journal

CASE REPORT
Year
: 2019  |  Volume : 2  |  Issue : 2  |  Page : 169--173

Foramen magnum syndrome after iatrogenic cerebrospinal fluid leak during lumbar spine surgery: A series of two cases


Siddharth A Badve1, Michael Galgano2, Richard A Tallarico2, William F Lavelle2,  
1 Department of Orthopedics, SUNY Upstate Medical University, Syracuse, NY; Carolina Pines Regional Medical Center, Hartsville Orthopedics and Sports Medicine, Hartsville, SC, USA
2 Department of Orthopedics, SUNY Upstate Medical University, Syracuse, NY, USA

Correspondence Address:
Dr. Siddharth A Badve
Hartsville Orthopedics and Sports Medicine, Carolina Pines Regional Medical Center, 700 Medical Park Drive, Hartsville, SC 29550
USA

Abstract

Foramen magnum syndrome (FMS) is a rare complication from lumbar spine surgery. Cerebrospinal fluid (CSF) leaks can be difficult to treat. FMS is a dangerous complication due to excessive distal CSF drainage from a dural tear or secondary to a “controlled” lumbar drainage. We present two cases of FMS after iatrogenic CSF leaks. Both patients underwent decompressive laminectomy as a part of the index surgery. Intraoperative dural tear was not identified in either case. A postoperative computed tomography (CT) myelogram ordered in view of the positional headaches indicated a CSF leak. A lumbar drain was placed, but both the patients worsened symptomatically. CT head in Case 1 indicated tonsillar ectopia within the foramen magnum, while that in Case 2 revealed a posterior fossa hemorrhage with fullness of the foramen magnum and profound hydrocephalus. Both patients were treated surgically. Additional corrective measures were also initiated to reverse the pathology. Both patients made a good recovery with resolution of symptoms. Development of neurological changes in a patient with CSF leak may indicate an acute intracranial process. Treatment of foramen magnum syndrome requires prompt realization of the underlying pathology and measures to cease or modulate the CSF drainage. The dangers of excessive distal CSF drainage, whether it is from a dural tear or from “controlled” lumbar drainage, should be considered.



How to cite this article:
Badve SA, Galgano M, Tallarico RA, Lavelle WF. Foramen magnum syndrome after iatrogenic cerebrospinal fluid leak during lumbar spine surgery: A series of two cases.Indian Spine J 2019;2:169-173


How to cite this URL:
Badve SA, Galgano M, Tallarico RA, Lavelle WF. Foramen magnum syndrome after iatrogenic cerebrospinal fluid leak during lumbar spine surgery: A series of two cases. Indian Spine J [serial online] 2019 [cited 2020 Jan 22 ];2:169-173
Available from: http://www.isjonline.com/text.asp?2019/2/2/169/263280


Full Text



 Introduction



Foramen magnum syndrome (FMS), also known as acquired Chiari malformation, is a rare complication of lumbar spine surgery. Iatrogenic dural tears occur in 1%–17% of spine surgeries. The incidence is influenced by factors such as case complexity.[1],[2],[3] Management of this complication can be difficult, especially if the tear goes unrecognized during the original surgery. Intraoperative durotomy can be treated with attempted primary closure, placement of a dural substitute, blood patch, or fibrin glue. If these methods fail, a lumbar drain is utilized to divert cerebrospinal fluid (CSF).

Leaks can result in spinal headaches from dural stretching, delayed wound healing, increased risk of surgical site infection, and, rarely, meningitis. In severe cases of CSF leak, negative pressure gradient between the spinal canal and the intracranial space may result in intracranial hypotension with devastating implications including cardiopulmonary arrest. We present two case illustrations of iatrogenic CSF leaks leading to intracranial hypotension and resultant FMS.

 Case Reports



Case 1

A 31-year-old morbidly obese male presented with left lower extremity radiculopathy of 13 years' duration with no neurological deficit. Magnetic resonance imaging (MRI) revealed canal stenosis at L4/5 and L5/S1. Due to the failure of the standard conservative treatment, the patient was offered surgical intervention in the form of L4-S1 laminectomy, foraminotomy, and discectomy. He developed a left-sided foot drop on the night of surgery and underwent re-exploration, hematoma evacuation and further L5 nerve root decompression on postoperative day (POD) 1. He was discharged with an ankle-foot orthosis on POD 2.

The patient returned at 2 weeks with positional headache and photophobia and was admitted with a concern of a CSF leak. A computed tomography (CT) myelogram demonstrated a left-sided CSF extravasation at L5 level. The lumbar drain was inserted along with epidural fibrin glue placement. The drain height was adjusted in relation to the external auditory meatus to maintain a CSF output of 10–15 ml every hour within the realms of the patient comfort and hemodynamic stability. The wound continued to drain in spite of these measures. A repeat CT myelogram demonstrated extravasation of CSF. The patient underwent reexploration, irrigation, and debridement. The dura was retracted with no identifiable lateral leaf for a primary repair. Synthetic collagen patch was placed over the defect, and a lumbar drain was again placed. Intraoperative wound cultures revealed methicillin-resistant Staphylococcus aureus (MRSA) infection. The drain height was adjusted to maintain a CSF output of 10–15 ml every hour. On POD 2, the lumbar drain output decreased significantly. The patient appeared to be more somnolent and confused.

The CT head showed fullness of the foramen magnum with suprasellar cistern effacement [Figure 1]. Due to the concern for impending tonsillar herniation, the CSF drainage was ceased. Two days later, the MRI demonstrated improved tonsillar positioning [Figure 2] and [Figure 3]. The patient remained neurologically stable. A surgical repair was attempted to suture medial dural leaf to the collagen patch while the lateral leaf was tucked under the thecal sac. A lumbar drain was again placed for CSF drainage, and the patient nursed in 15° of reverse Trendelenburg for 4 days. Appropriate intravenous antibiotics for his MRSA infection were administered. The patient demonstrated no further findings of a CSF leak and hence was discharged from the hospital without any further problems. The patient was followed up for 4 years and 9 months at regular intervals and continued to be free of symptoms.{Figure 1}{Figure 2}{Figure 3}

Case 2

A 51-year-old hypertensive male with prior L4/5 decompressive laminectomy and instrumented fusion presented with severe neurogenic claudication and lumbar radicular symptoms, but no neurological deficit. MRI of the lumbar spine revealed adjacent segment disease with significant stenosis at L2/3 and L3/4. As his symptoms were unresponsive to conservative treatment, he underwent a revision L2–4 decompressive laminectomy with L2–5 instrumented fusion with meticulous separation of the scar without any dural violation. Within 48 h of surgery, the patient complained of a severe positional headache. A CT myelogram [Figure 4]a and [Figure 4]b revealed extravasation of contrast at the L4 level, warranting placement of a lumbar drain at L2 level and fibrin glue injection at the site of the dural leak. The drain height was adjusted to optimize the output at 10–15 ml/h. A sudden elevation in the blood pressure (systolic >200 mmHg) along with extreme lethargy was noted. A CT head revealed bilateral cerebellar hemorrhage, effacement of the fourth ventricle, hydrocephalus, and tonsillar descent into the foramen magnum [Figure 5]a, [Figure 5]b, [Figure 5]c, [Figure 5]d. The lumbar drain was promptly clamped. A neurosurgical evaluation and an emergent right frontal external ventricular drain placement were done [Figure 6]. Over the next few days, the patient improved in his orientation and alertness. A surgical repair of the dural tear and augmentation with synthetic patch and fibrin glue was achieved. The external ventricular drain was eventually weaned and safely removed. The follow-up MRI of the brain revealed resolution of the prior findings [Figure 7]. The patient suffered no neurological sequelae and was relieved of the radicular symptoms. The patient was followed up for 2 years and 9 months at regular intervals and continued to be free of symptoms.{Figure 4}{Figure 5}{Figure 6}{Figure 7}

 Discussion



FMS is a constellation of clinical findings in the setting of cerebellar tonsillar ectopia. Yasuoka and Takakura proposed the definition and detailed the various neurological sequelae.[4] However, great variability exists with the presentation. A Chiari I malformation (primary congenital tonsillar ectopia) is common, and the symptoms dependent on the CSF flow dynamics around the brainstem.

Multiple acquired etiologies can contribute to intracranial hypertension to “push” the cerebellar tonsils into the foramen magnum. In contrast, intracranial hypotension can also cause cerebellar tonsillar descent, usually secondary to distal CSF diversion. In essence, the tonsils are “pulled,” rather than “pushed,” through the foramen magnum as a result of a negative pressure gradient existing between the cranial and spinal theca, with the most likely pathology being at the spinal level.[5],[6],[7],[8],[9] Acute tonsillar herniation can be a fatal event depending on the rapidity and degree of descent, making this a very important clinical entity to diagnose and treat swiftly.[10]

Numerous etiologies of “crowding” within the foramen magnum exist that may predispose development of tonsillar herniation secondary to the alteration in the CSF flow dynamics. A Chiari I malformation (primary congenital tonsillar ectopia) is common. However, these patients may not always be symptomatic, depending on the CSF flow around the brainstem. On the other hand, acquired etiologies such as a supratentorial mass lesion also can “push” the cerebellar tonsils into the foramen magnum. This is a form of intracranial hypertension. Lack of preoperative cranial imaging in our patients makes it impossible to attest to any predisposing factors such as low-lying tonsils or preexisting Chiari malformation.

At the primary surgery, no dural violation was noted in both patients. In accordance with the institutional protocol, the Valsalva maneuver was performed before the wound closure with no evidence of CSF leak. In regard to the occult nature of the CSF leak in Case 2 which was a revision decompression surgery, the development of a minor dural rent without frank violation of the arachnoid is a possibility. Dural tears with an intact arachnoid membrane can still expand over time and, with alteration of CSF dynamics, may lead to a CSF leak. Revision surgery appears to be the most significant risk factor for intraoperative durotomy.

 Conclusion



Development of neurological changes in a patient with CSF leak should raise the concern of acute intracranial process. Treatment of FMS requires prompt realization of the underlying pathology and measures to cease the CSF drainage. Certain situations may need proximal CSF drainage. This case series highlights the dangers of excessive distal CSF drainage, whether it is from a dural tear or from “controlled” lumbar drainage.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgment

We would like to acknowledge Eric Emberton.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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