CASE 41

By: Dr. Mai Mattar, MD and Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: A 30-year-old male whom had undergone disc surgery one month ago. Developed pain following surgery.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

Axial T1 and T2, post contrast sagittal T1Fs and a myelogram image showing abnormal accumulation of CSF across the laminectomy defect extending into the paraspinal musculature. We cannot appreciate nerve root clumping or retraction.

DIFFERENTIAL DIAGNOSIS:

• Pseudomeningocele.

• Meningocele.

• Arachnoiditis.

• Post-operative collection.

DIAGNOSIS:

Post-operative pseudomeningocele.

PEARLS AND DISCUSSION:

Pseudomeningocoele refers to an abnormal collection of cerebrospinal fluid (CSF) that occurs due to leakage from the CSF-filled spaces surrounding the brain and spinal cord because of trauma or surgery. The salient feature of pseudomeningocele is that it contains CSF that communicates with the CSF surrounding the brain or spinal cord and it is not lined by dura.

A pseudomeningocele can occur any time when there is an opening of the dura mater. It can be occult or apparent and found incidentally or purposely. Its most common cause is by far iatrogenic, but traumatic and congenital causes may also be implicated. During extradural surgery such as a laminectomy, the dura may be breached by direct trauma, excessive dural or nerve root traction, or dural laceration from sharp bone fragments. Lumbar puncture, inadvertent dural puncture after placing an epidural catheter, or myelography needle puncture are other causes of CSF leaks. In cases that require invasion into the dura, such as repair of a tethered cord or resection of intradural tumors, a dural defect may occur if a watertight closure has not been achieved. Leakage may result even if one recognizes improper suturing of dural defects, particularly in anterior defects, which are difficult to repair.

In contrast to a meningocele, in which the fluid is surrounded and confined by dura mater, in a pseudomeningocele, the fluid has no surrounding membrane, but is contained in a cavity within the soft tissues.

Treatment for pseudomeningocele is conservative or may involve neurosurgical repair.

FURTHER READING:

1. Mehendale NH, Samy RN, Roland PS. Management of pseudomeningocele following neurotologic procedures. Otolaryngol Head Neck Surg. 2004;131 (3): 253-62. 

2. Abdulhak M, Marzouk S. Challenging Cases in Spine Surgery. Thieme. (2011) ISBN:1604064897