Air Embolus to Arachnoid Cyst as a Rare Delayed Complication of Intrathecal Medication Delivery

Symptomatic secondary spinal arachnoid cysts: a systematic review

BACKGROUND

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 to 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.

METHOD

An electronic literature search of the PubMed database was conducted for studies on secondary spinal arachnoid cysts between 1990 to 2022. Non-English publications, non-human studies, reports of a primary cyst, studies not including case details, and studies of non-symptomatic 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, 1 intradural/extradural, 1 interdural, and 1 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 = 0.0248, Gehan-Breslow-Wilcoxon test: P = 0.0126). 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.

CONCLUSION

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 (e.g., 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.

Advances in intrathecal drug delivery

PURPOSE OF REVIEW

Targeted intrathecal drug delivery systems (IDDS) are an option in algorithms for the treatment of patients with moderate-to-severe chronic refractory pain. This article is intended to review the literature regarding IDDS published over the last year, with special attention to the Polyanalgesic Consensus Conference 2012.

RECENT FINDINGS

The recommendations made by the Polyanalgesic Consensus Conference 2012 are reviewed. Separate considerations of intrathecal drug therapy for neuropathic and nociceptive pain syndromes and the new concept of 'microdosing' are discussed in this article.

SUMMARY

This review includes the recommendations for the use of IDDS, trialing, and recent reports of complications (especially, the occurrence of granulomas). In addition, the latest documents on cerebrospinal fluid and potential lines of future development are discussed.