Unknown case. Spinal claudication caused by an arachnoid cyst

[Clinical presentation of a dorsal epidural arachnoid cyst after an epidural anesthesia]

BACKGROUND

Arachnoid cysts are dural diverticula with liquid content similar to cerebrospinal fluid, with 1% occurring in the spinal cord. They locate mainly in the dorsal region of the thoracic spine, and are unusual causes of spinal cord compression.

CLINICAL CASE

The case is presented of a previously healthy 15-year-old boy, with a 20-month history of spastic paraparesis that started apparently after epidural block for ankle osteosynthesis. There was decreased sensitivity and strength of the pelvic limbs and gradually presented with anaesthesia from T12 to L4 dermatomes, L5 and S1 bilateral hypoaesthesia and 4+/5 bilateral strength, in the L2 root and 2+/5 in L3, L4, L5, S1, hyperreflexia, Babinski and clonus, but with no alteration in the sacral reflexes. In the magnetic resonance it was diagnosed as an extradural arachnoid cyst from T6 to T9. The patient underwent a T6 to T10 laminotomy, cyst resection, dural defect suture, and laminoplasty. One year after surgery, the patient had recovered sensitivity, improvement of muscle strength up to 4+/5 in L2 to S1, and normal reflexes.

CONCLUSIONS

After the anaesthetic procedure, increased pressure and volume changes within the cyst could cause compression of the spinal cord, leading to symptoms. Despite being a long-term compression, the patient showed noticeable improvement.

Spinal arachnoid cysts in the pediatric population: report of 31 cases and a review of the literature

OBJECT

The goal of this study was to review all cases of pediatric spinal arachnoid cysts (SACs) surgically treated at the authors' institution between 1992 and 2008 and to compare these cases to the published literature for the general population.

METHODS

The charts of all pediatric patients with SACs were reviewed for demographics, medical history, presenting symptoms, imaging findings, operative procedure(s), complications, and outcomes. Following a complete literature review, the pediatric data were compared with data from the general population and unique findings associated with pediatric patients were identified.

RESULTS

Thirty-one pediatric patients (median age 6.9 years) underwent operative intervention for SACs between 1992 and 2008 (median duration of follow-up 4.2 years). There were 17 female patients (55%) and 14 male patients (45%). Twenty-one patients (68%) presented with symptoms of radiculopathy or myelopathy. The most common presenting symptoms were pain (42%), lower-extremity weakness (39%), gait instability (32%), spasticity (19%), sensory loss (10%), and bladder dysfunction (7%). In 3 patients (10%) SACs were incidental findings. Intradural SACs were more common (18 patients, 58%) than extradural SACs (11 patients, 36%). One patient (3%) had extradural and intradural components. One patient (3%) had a purely intramedullary cyst, and 1 patient (3%) had both an intradural and intramedullary component. Of the 18 intradural SACs, 9 (50%) were located ventral to the spinal cord and 9 (50%) were dorsally situated. One dorsal intradural SAC had an intramedullary component. All extradural SACs were located dorsal to the spinal cord. Intradural SACs were primarily concentrated in the cervical and thoracic regions (67%), whereas extradural cysts were more evenly distributed between the thoracic, lumbar, and sacral regions. Of the 18 patients with intradural SACs, 13 (72%) had significant previous CNS abnormalities, compared with 3 (27%) of 11 patients with extradural SACs. There were 2 operative complications. One patient had a CSF leak treated with a lumbar drain, and the second patient had a pseudomeningocele. No patients had neurological deterioration as a result of surgical intervention. Twenty-one patients (68%) had complete remission of symptoms, 6 (19%) had improvement, 3 (10%) were stable, and 1 (3%) has worsening of symptoms with recurrence that ultimately required cystoperitoneal shunting, despite multiple failed attempts at fenestration.

CONCLUSIONS

Spinal arachnoid cysts are rare lesions in the pediatric population. Affected patients present with back pain, weakness, and/or gait instability. In children, SACs predominantly develop in the thoracic region and are more likely to occur intradurally, compared with SACs in the general population. Overall outcomes following surgical fenestration or excision of SACs are excellent, with complete remission or improvement of symptoms achieved in 87% of cases.