Age / Sex : 57 / F

Chief complaint :

low back pain and both thigh pain, Spine OP. Hx.(20 years ago)

What is your impression?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy of Hee Seok Jeong, Pusan National University Yangsan Hospital

Discussion

Answer:

 Post-operative Pseudomeningocele  

Findings:

MR:

s/p both laminectomy state at T12-L3

Loculated cystic lesion at the epidural and intradural space with foraminal widening at T11-L4 level
- with communicated thecal sac of T12/L1-L3/4 level

Differential Diagnosis:

Paraspinous abscess

Postoperative hematoma

Diagnosis:  

Post-operative Pseudomeningocele

Discussion:

• First described by Hyndman and Gerber in 1946


• Pseudomeningocele

  ☞ extravasated collections of extradural cerebrospinal fluid (CSF) that result

      from a dural tear

• Rare complication of an unintended durotomy during spinal surgery


• Incidence of postoperative pseudomeningocele in lumbar laminectomy

    patients

     ☞ 0.07% to 2%

     ☞ approximately 61 cases of post laminectomy pseudomeningoceles

         have been reported

• Tear of both the dural and arachnoid layers ⇒ Ball valve phenomenon ⇒

     CSF accumulation ⇒ Formation of an extradural cyst

• CSF (initially) ☞ absorbed easily

   ⇒ reactive fibrous septations (reabsorption is hindered)

   ⇒ fibrous capsule formation

   ⇒ pseudocyst wall ☞ herniation of nerve roots

• Interval between primary surgery and formation of pseudomeningocele

   ☞ from a few months to years

• Size of the pseudomeningocele

   ☞ size of dural tear and also on the level of incidental durotomy

   ☞ lumbar spine (higher intraspinal pressure in erect posture)

      ▶ greater incidence of pseudomeningocele formation

• Signs and symptoms

   ☞ low back pain (exacerbated on sneezing and coughing)

   ☞ radicular symptoms (herniation of nerve roots in the cyst cavity)

   ☞ rarely motor deficits and sphincter dysfunction

   ☞ delayed infection

       (reported by Koo et al. in 1986 and James et al. in 1996)

• Treatment (varied)

   ☞ small asymptomatic pseudomeningoceles

    ▶ monitored periodically and managed conservatively

   ☞ symptomatic, large pseudomeningocele

    ▶ surgery

    (extirpation of pseudomeningocele sac with repair of incidental durotomy)

     ð If nerve roots are present within the cyst

          à need to be repositioned inside dural cavity

References:

1. Rakesh G, Sharadendu N. Post-operative Pseudomeningocele after Spine Surgery: Rare Cause of

Failed Back Syndrome. Iranian Journal of Neurosurgery 2016;2(1):15-18

2. Macki M, Lo SF, Bydon M, Kaloostian P, Bydon A. Post-surgical thoracic pseudomeningocele 

causing spinal cord compression. Journal of Clinical Neuroscience 2014;21(3):367-72