ABSTRACT
BACKGROUND AND IMPORTANCE: Complete posterior atlantoaxial dislocation (PAAD) with an unfractured odontoid process is a rare condition where a dislocated but intact odontoid process is positioned ventrally to the anterior arch of C1. This lesion is related to transverse and alar ligament rupture secondary to hyperextension and rotatory traumatic injury and is often associated with neurological deficit. The treatment strategy remains controversial, and in many cases, odontoidectomy is required. Traditional approaches for odontoidectomy (transnasal and transoral) are technically demanding and are related to several complications. This article describes a 360° reduction and stabilization technique through a navigated anterior full-endoscopic transcervical approach (nAFETA) as a novel technique for odontoidectomy and C1-C2 anterior transarticular fixation supplemented with posterior fusion. CLINICAL PRESENTATION: A 21-year-old man presented to the emergency room by ambulance after a motorcycle accident. On evaluation, incomplete ASIA B spinal cord injury was documented. Imaging revealed a complete PAAD. We performed a two-staged procedure, a nAFETA odontoidectomy plus C1-C2 anterior transarticular fixation followed by posterior C1-C2 wired fusion. At a 2-year follow-up, the patient had a 10-point Oswestry Disability Index score and neurological improvement to ASIA E. CONCLUSION: PAAD can be successfully treated through minimally invasive nAFETA. Noteworthy, the risks of the transoral and endonasal routes were avoided through this approach. In addition, nAFETA allows anterior transarticular fixation during the same procedure providing spinal stability. Further studies are required to expand the use of nAFETA in this field.
ABSTRACT
BACKGROUND: Intraventricular meningiomas (IVMs) are rare tumors with considerable treatment-associated morbidity due to their challenging location. Treatment with stereotactic radiosurgery (SRS) is sparsely reported in the literature. We describe our experience over the last 35 years using Gamma knife radiosurgery (GKRS) for IVMs. METHODS: We retrospectively reviewed the GKRS database identifying 2501 meningiomas treated at the University of Pittsburgh Medical Center over the last 35 years. Nineteen patients with (12 males, mean age = 53.2 years, range 14-84) 20 IVMs were identified. Headache was the most frequent presenting symptom (N = 12), and the trigone of the lateral ventricle was the most common location (N = 18). The median tumor volume was 4.8 cc (range, 0.8-17). The median margin dose was 14 Gy (range, 12-25) delivered at 50% isodose line. RESULTS: At a median follow-up of 63.1 months (range, 6-322.4) symptom control was achieved in 18 (94.7%) patients. The overall progression-free survival (PFS) was 95% at 5 years, and 85% at 10-years. After Log-rank test, patients who underwent GKRS within 12 months after diagnosis (vs. ≥ 12 months, X2: 4.455, p = 0.035), patients treated with primary GKRS without prior biopsy (vs. prior biopsy, X2: 4.000, p = 0.046), and patients with WHO grade I meningioma (vs. WHO II, X2: 9.000, p = 0.003) had a longer PFS. Imaging showed peritumoral edema in seven cases at a median of 10.5 (range, 6.13-24.3) months after GKRS. Only three of these patients were symptomatic and were successfully managed with oral medications. Cox´s regression revealed that a V12Gy ≥ 10 cc [HR: 10.09 (95% CI: 2.11-48.21), p = 0.004], and tumor volume ≥ 8 cc [HR: 5.87 (95% CI: 1.28-26.97), p = 0.023] were associated with a higher risk of peritumoral edema. CONCLUSION: GKRS is an effective and safe management option for intraventricular meningiomas. Early GKRS should be considered as a primary management modality for small and medium sized IVM and adjuvant management for residual IVMs.
