Spinal subdural hygroma

BACKGROUND Spinal cysts in the interdural space are extremely rare and are not included in the standard classification of spinal meningeal cysts. OBSERVATIONS A 60-year-old female presented to our hospital with a spastic gait and numbness in both palms. Magnetic resonance imaging (MRI) revealed a spinal cyst from C4 to T4 compressing the spinal cord. Computed tomography myelography revealed a fistula at C4–5 and C5–6 that connected the cyst along the right C5 and C6 root sleeves. The cyst was located within the dura mater, and communication with the arachnoid space was achieved using a shunt tube. There was partial spastic gait amelioration after the procedure, but the patient experienced a relapse 2 months postoperation. A repeat procedure was performed without a shunt tube to allow greater communication between the cyst and the subarachnoid space. After this, marked improvement in gait function was observed, and MRI showed a significant reduction in cyst volume. LESSONS Interdural spinal meningeal cysts are rare. When the interdural cyst cannot be removed entirely, surgery may be appropriate for providing a shunt tube or establishing communication between the cyst and arachnoid space to maintain the circulation of cerebrospinal fluid collected in the cyst cavity.

Section: Discussionmentioning

confidence: 73%

An interdural spinal cyst in the cervicothoracic spine: a review and proposal for a revised classification of spinal meningeal cysts. Illustrative case

Kawasaki

Takayama

Maki³

et al. 2022

“…A possible reason for the unilateral passage of CSF from the subarachnoid space to the subdural space is the effect of pressure changes in the meningeal compartments. 7 Monro-Kellie proposed that the sum volumes of the brain, CSF, and intracranial blood are constant. 8 Severe lumbar canal stenosis causes intradural pressure disparity between the upper and lower levels of canal stenosis.…”

Section: Discussionmentioning

confidence: 99%

“… 12 CSF may be transported from the subarachnoid space into the interstitial space of the dura through various mechanisms (i.e., along exiting nerves, exiting vessels, transcellular transport, and arachnoid granulations). 7 …”

Section: Discussionmentioning

confidence: 99%

Asymptomatic spinal subdural epiarachnoid hygroma after lumbar laminectomy for lumbar spinal canal stenosis: illustrative case

Kawasaki

Takayama

Maki³

et al. 2022

BACKGROUND Spinal subdural epiarachnoid hygroma (SSEH) after lumbar laminectomy is an extremely rare complication. OBSERVATIONS An 84-year-old man presented to the hospital with lower back pain, radicular pain, and numbness in the lateral aspect of the left leg. Magnetic resonance imaging (MRI) revealed anterior lumbar spondylolisthesis at L3, severe disc herniation at L3–4, and severe lumbar spinal canal stenosis at L3–4 and L4–5. Lumbar laminectomy at L3–4 and L4–5 and discectomy at L3–4 were performed without complications such as cerebrospinal fluid (CSF) leakage and durotomy intraoperatively. Although lower back pain and numbness at the lateral aspect of the left leg were resolved postoperatively, postoperative MRI showed spinal nerve deviation to the ventral side due to SSEH from T12 to S1. Conservative therapy was performed for asymptomatic SSEH, and MRI 1 week postoperatively indicated improved ventral spinal nerve deviation and reduced SSEH. LESSONS SSEHs after posterior decompression without durotomy are extremely rare. Asymptomatic SSEHs may resolve with conservative treatment. However, surgery should be performed to decompress hygroma in patients with symptomatic SSEH.

“…[18][19][20] These authors theorize that given the diluting and redistributing effect of CSF, the hemorrhage within the subarachnoid space may be washed away, leaving only the SSH. 21 SSH has also been shown to be a result of traumatic introduction of blood into the subdural space by a traumatic lumbar puncture. 22,23 In these cases, postmortem examination found laceration of radicular vessels to be the source of the bleeding, which was traumatically introduced into the subdural space.…”

Section: Pathophysiologymentioning

confidence: 99%

Postoperative spinal subdural hygroma without incidental durotomy: illustrative cases

Barr

Mayer

2021

BACKGROUND Spinal subdural hygroma (SSH) is a rare pathological entity occurring as a complication of spinal surgery. It is different from spinal subdural hematoma due to blunt trauma, anticoagulation therapy, spinal puncture, and rupture of vascular malformations. OBSERVATIONS The authors presented five patients with SSH who received decompression for lumbar stenosis. None had incidental durotomy. All presented postoperatively with unexpectedly severe symptoms, including back and leg pain and weakness. Postoperative magnetic resonance imaging (MRI) revealed SSH with a characteristic imaging finding termed the “flying bat” sign. Four patients underwent evacuation of SSH, with immediate and complete resolution of symptoms in three patients and improvement in one patient. One patient improved without additional surgery. At surgery, subdural collections were found to be xanthochromic fluid in three patients and plain cerebrospinal fluid (CSF) in one patient. LESSONS Unexpectedly severe back and leg pain and weakness after lumbar or thoracic spine surgery should raise suspicion of SSH. MRI and/or computed tomography myelography shows the characteristic findings termed the flying bat sign. Surgical evacuation is successful although spontaneous resolution can also occur. The authors hypothesized that SSH is due to CSF entering the subdural space from the subarachnoid space via a one-way valve effect.