Isolated subependymal giant cell astrocytoma (SEGA) in the absence of clinical tuberous sclerosis: two case reports and literature review.

PURPOSE: Subependymal giant cell astrocytoma (SEGA) is a WHO grade I pediatric glioma arising in 5-15% of patients with tuberous sclerosis (TSC). Rare cases of isolated SEGA without TSC have been described. The etiology, genetic mechanisms, natural history, and response to treatment of these lesions are currently unknown. We describe two such cases of isolated SEGA with follow-up. METHODS: Retrospective review was performed at a single institution to describe the clinical course of pathology-confirmed SEGA in patients with germline testing negative for TSC mutations. RESULTS: Two cases of isolated SEGA were identified. Genetic analysis of the tumor specimen was available for one, which revealed an 18 base pair deletion in TSC1. Both cases were managed with surgical resection, one with preoperative embolization. In spite of a gross total resection, one patient experienced recurrence after three years. Treatment with an mTOR inhibitor led to a significant interval reduction of the mass on follow-up MRI. The patient tolerated the medication well for 6 years and is now off of treatment for 2 years with a stable lesion. CONCLUSION: Cases of SEGA outside of the context of TSC are exceedingly rare, with only 48 cases previously described. The genetic mechanisms and treatment response of these lesions are poorly understood. To date, these lesions appear to respond well to mTOR inhibitors and may behave similarly to SEGAs associated with TSC. However, given that experience is extremely limited, these cases should be followed long term to better understand their natural history and treatment response.

Utility of prolonged prophylactic systemic antibiotics for wound drains in posterior spine surgery: a systematic review and meta-analysis.

OBJECTIVE: Closed suction drains, often used after posterior spinal surgery, pose a potential risk of infection. To combat this risk, many surgeons opt for a prolonged prophylactic antibiotic regimen. Since 2015, several studies have shown that prolonged prophylactic systemic antibiotics (PPSA) for drains provides no additional benefit in reducing surgical site infection (SSI) rates. However, most of these studies lacked sufficient power to make reliable conclusions. To date, there has been no meta-analysis conducted to further investigate this issue. The aim of this study was to investigate whether a regimen of PPSA reduces the incidence of deep SSIs in adult patients with closed suction drains following posterior spinal surgeries. METHODS: The protocol of the current systematic review was registered with PROSPERO. A systematic review of the literature in PubMed (Medline), Europe PMC, Embase, and Cochrane Review databases was conducted for all relevant literature with the keywords "spine," "antibiotics," "surgical site infection," "prophylaxis," and "drain." Retrospective and prospective studies investigating the effectiveness of PPSA in patients 18 years or older who underwent posterior cervical or thoracolumbar surgery and had postoperative wound drains were included. The primary outcome was the odds ratio for deep SSI based on the intervention (PPSA vs non-PPSA). The secondary outcomes were the rates of superficial and overall SSIs. RESULTS: From a total of 2558 titles identified from the search, 7 studies were chosen for final analysis. Three were randomized controlled trials (RCTs), and 4 were retrospective reviews. A total of 2446 patients were analyzed; 1149 received a PPSA regimen and 1297 received a non-PPSA regimen. Deep SSIs occurred in 45 patients (3.9%) and 46 patients (3.5%) in the PPSA and non-PPSA groups, respectively. The odds ratio for deep SSIs in the PPSA group compared with the non-PPSA group was 1.10 (95% CI 0.69-1.74), which was not statistically significant. Additionally, there were no differences in the rates of superficial and overall SSIs. There was a trend toward increased infections with multidrug-resistant bacteria (Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus) in the PPSA group; however, it was not possible to perform a durable statistical analysis because of the small number of reported organisms in the selected publications. CONCLUSIONS: This meta-analysis demonstrates that there is no reduction in rate of deep, superficial, and overall SSIs with prolonged prophylactic antibiotics after posterior spinal surgery involving the use of closed suction drains.

Does the Modified Arrhenius Model Reliably Predict Area of Tissue Ablation After Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Pediatric Lesional Epilepsy?

BACKGROUND: Commercial magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) systems utilize a generalized Arrhenius model to estimate the area of tissue damage based on the power and time of ablation. However, the reliability of these estimates in Vivo remains unclear. OBJECTIVE: To determine the accuracy and precision of the thermal damage estimate (TDE) calculated by commercially available MRgLITT systems using the generalized Arrhenius model. METHODS: A single-center retrospective review of pediatric patients undergoing MRgLITT for lesional epilepsy was performed. The area of each lesion was measured on both TDE and intraoperative postablation, postcontrast T1 magnetic resonance images using ImageJ. Lesions requiring multiple ablations were excluded. The strength of the correlation between TDE and postlesioning measurements was assessed via linear regression. RESULTS: A total of 32 lesions were identified in 19 patients. After exclusion, 13 pairs were available for analysis. Linear regression demonstrated a strong correlation between estimated and actual ablation areas (R2 = .97, P < .00001). The TDE underestimated the area of ablation by an average of 3.92% overall (standard error (SE) = 4.57%), but this varied depending on the type of pathologic tissue involved. TDE accuracy and precision were highest in tubers (n = 3), with average underestimation of 2.33% (SE = 0.33%). TDE underestimated the lesioning of the single hypothalamic hamartoma in our series by 52%. In periventricular nodular heterotopias, TDE overestimated ablation areas by an average of 13% (n = 2). CONCLUSION: TDE reliability is variably consistent across tissue types, particularly in smaller or periventricular lesions. Further investigation is needed to understand the accuracy of this emerging minimally invasive technique.

Comparison of Clinical and Radiographic Outcomes After Standalone Versus Cage and Plate Constructs for Anterior Cervical Discectomy and Fusion.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) has conventionally been performed using an allograft cage with a plate-and-screw construct. Recently, standalone cages have gained popularity due to theorized decreases in operative time and postoperative dysphagia. Few studies have compared these outcomes. Here, we directly compare the outcomes of plated versus standalone ACDF constructs. METHODS: A single-center retrospective review of patients undergoing ACDF after June 2011 with at least 6 months of follow up was conducted. Clinical outcomes were analyzed and compared between standalone and plated constructs. Multivariate regression analysis of the primary outcome, need for revision surgery, as well as several secondary outcomes, procedure duration, estimated blood loss (EBL), length of hospital stay, disposition, and incidence of dysphagia, hoarseness, or surgical site infection, was completed. RESULTS: A total of 321 patients underwent ACDF and met inclusion-exclusion criteria, with mean follow-up duration of 20 months. Forty-six (14.3%) patients received standalone constructs, while 275 (85.7%) received plated constructs. Fourteen (4.4%) total revisions were necessary, 4 in the standalone group and 10 in the plated group, yielding revision rates of 8.7% and 3.6%, respectively (P = .125). Mean EBL was 98 mL in the standalone group and 63 mL in the plated group (P = .001). Mean procedure duration was 147 minutes in the standalone group and 151 minutes in the plated group (P = .800). Mean hospital stay was 3.6 days in the standalone group and 2.5 days in the plated group (P = .270). There was no significant difference in incidence of dysphagia (P = .700) or hoarseness (P = .700). CONCLUSIONS: Standalone ACDF demonstrates higher, but not statistically significant, revision rates than plate-and-screw constructs, without the hypothesized decreased incidence of dysphagia or hoarseness and without decreased procedure duration or EBL. Surgeons may consider limiting use of these constructs to cases of adjacent segment disease. Larger studies with longer follow up are necessary to make more definitive conclusions. LEVEL OF EVIDENCE: 4. CLINICAL RELEVANCE: This study will help spine surgeons decide between using standalone or cage-and-plate constructs for ACDF.