Post-Spinal Anesthesia Intradural Extramedullary Arachnoid Cyst Formation: A Case Report.

The formation of an intradural extramedullary arachnoid cyst is a rare complication of spinal anesthesia. We present a case of a 34-year-old female patient who developed neurological symptoms including a bilateral reduction in sensation and strength in the lower limbs following a C-section under spinal anesthesia. MRI of the thoracic spine revealed a lesion at the level of T11/T12 and the upper limit of the L1 vertebral body, which was pushing the cord to the side, and a diagnosis of the intradural extramedullary arachnoid cyst was established. The prognosis for this condition is good and surgical excision leads to resolution of the symptoms. Proper and prompt diagnosis is crucial to rule out other differentials and prevent permanent neurological damage in these patients.

Symptomatic secondary spinal arachnoid cysts: a systematic review.

BACKGROUND CONTEXT: Secondary spinal arachnoid cysts have rarely been reported but present significant challenges for management. These cysts could be anteriorly located with long rostral-caudal extensions and many are related to arachnoiditis, leading to difficult-to-treat disorders. Thus far, due to the scarcity of reports, the features of the disease and the optimal therapeutic strategies remain unclear. PURPOSE: To investigate clinical features and the optimal treatment modalities of secondary spinal arachnoid cysts compared with primary spinal arachnoid cysts. STUDY DESIGN: Systematic review. PATIENT SAMPLE: Systematic review identified 103 secondary cases from 80 studies and reports. OUTCOME MEASURES: Condition of symptom relief and duration of treatment response were analyzed. METHODS: An electronic literature search of the PubMed database was conducted for studies on secondary spinal arachnoid cysts between 1990 and 2022. Non-English publications, nonhuman studies, reports of a primary cyst, studies not including case details, and studies of nonsymptomatic cases were excluded. RESULTS: This systematic review included 103 secondary cases. The most commonly reported etiologies were iatrogenic factors, trauma, and subarachnoid hemorrhage, accounting for 88 intradural extramedullary, 11 extradural, one intradural/extradural, one interdural, and one intramedullary spinal arachnoid cyst after a median duration of 30, 12, and 9 months, respectively. Extradural cysts were more prone to occur at dorsal locations and affect thoracic segments (mean cyst length: 3.4 segments). Intradural cysts showed a relatively higher ventral/dorsal ratio (1:1.09, 1.75:1, and 3.50:1 for cysts occurring from iatrogenic factors, trauma, and subarachnoid hemorrhage, respectively) and thoracic distribution, with a mean cyst length of 4.3 segments (5.1 for ventral and 3.5 for dorsal cysts). For intradural cysts, recurrence risk was lower after surgical resection than after fenestration/marsupialization (12-month recurrence risk: 21.43% vs 50.72%, log-rank test: p=.0248, Gehan-Breslow-Wilcoxon test: p=.0126). In cases treated with shunting, one recurrence (1/8 cases) was noted after external shunting and two recurrences (2/5 cases) after internal shunting at a median follow up of 12 months. CONCLUSIONS: Secondary spinal arachnoid cysts, particularly intradural cysts, are rarer and more challenging to treat than primary spinal cysts. Although fenestration/marsupialization is the commonly adopted treatment, the recurrence rate is high. For unresectable cysts, shunting procedures, particularly shunting into a body cavity (eg, pleural or peritoneal cavity) away from the subarachnoid space, could be a therapeutic alternative besides fenestration/marupialization, yet its efficacy requires confirmation by more data.

Surgical treatment of a thoracic ventral intradural arachnoid cyst associated with syringomyelia: case report.

The pathogenesis of thoracic ventral intradural spinal arachnoid cyst (ISAC) is unknown due to its extremely low incidence. In addition, its surgical treatment is complicated because of the ventral location, large craniocaudal extension, and frequent coexistence of syringomyelia. The optimal surgical strategy for thoracic ventral ISAC remains unclear and continues to be a matter of debate. In this report, the authors describe an extremely rare case presenting with a compressive thoracic ventral ISAC associated with syringomyelia that was successfully treated with a simple cyst-pleural shunt. The patient's medical history revealed bacterial spinal meningitis along with an extensive spinal epidural abscess, suggesting the incidence of extensive adhesive arachnoiditis (AA) to be a plausible cause for this pathology. Thoracic ventral ISAC reportedly occurs secondary to AA and is commonly associated with syringomyelia. Placement of a cyst-pleural shunt is an effective, safe, and uncomplicated surgical strategy, which can provide sufficient cyst drainage regardless of the coexistence of AA, and thus should be considered as primary surgical treatment. Syrinx drainage could be reserved for a later attempt in case the cyst-pleural shunt fails to reduce the extent of syringomyelia.

Clinical and Radiologic Outcomes After Fenestration and Partial Wall Excision of Idiopathic Intradural Spinal Arachnoid Cysts Presenting with Myelopathy.

BACKGROUND: Intradural spinal arachnoid cysts (ISACs) with associated neurologic deficits are encountered infrequently. Various management strategies have been proposed with minimal data on comparative outcomes. OBJECTIVE: We describe the clinical and radiologic presentation as well as the outcomes of 14 surgically managed patients who presented with an ISAC and associated myelopathy. METHODS: We retrospectively reviewed the clinical course of consecutive patients presenting with neurologic deficits associated with idiopathic ISACs at our institution. The diagnoses were based on preoperative magnetic resonance imaging studies followed by intraoperative and histopathological confirmation. RESULTS: A total of 14 consecutive patients with ISACs (1 cervicothoracic, 12 thoracic, and 1 thoracolumbar) and associated myelopathy were identified. Syringomyelia was noted in 8 patients. All ISACs were treated with cyst fenestration and partial wall resection through a posterior approach. Preoperative neurologic symptoms were noted to be stable or improved in all patients starting at 6-week postoperative follow-up. The median (interquartile range) preoperative mJOA score was 13 (12.0-14.8), whereas the postoperative median score at a mean follow-up of 22 months (range 6-50 months) was 16 (14.0-17.0), which represents a median improvement (ΔmJOA) of 2.0 (1.3-3.0) (P < 0.001). Comparison of ΔmJOA scores between cases without and with associated syrinxes did not reveal a significant difference (P = 0.23). Postoperative magnetic resonance imaging scans revealed spinal cord re-expansion at the level of the ISAC in all cases and either complete or partial syrinx resolution in 7 of 8 cases. CONCLUSIONS: Early treatment with fenestration and partial wall resection allows for cord decompression, syrinx resolution, and gradual resolution of myelopathic symptoms in most cases.