Bilateral Versus Unilateral Cranialization in the Management of a Breached Frontal Sinus.

BACKGROUND: Frontal sinus breach during craniotomy may occur inadvertently or intentionally. Management of a breached frontal sinus is controversial as numerous operative techniques have been described. Frontal sinus breach may result in life-threatening complications, require additional surgeries, and increase the risk for long-term infectious sequelae. A literature review found a paucity of neurosurgical reports examining breached frontal sinus management or specific analyses of unilateral versus bilateral frontal sinus cranialization. OBJECTIVE: A frontal sinus cranialization technique employed for patients involving frontal sinus breach and analyze outcomes managed with bilateral versus unilateral cranialization was presented in this study. METHODS: A retrospective review of outcomes was performed using our Institutional Review Board-approved surgical case database between September 2012 and September 2018. RESULTS: Thirty-three frontal sinus cranializations following frontal sinus breach were identified. Average follow-up time was 25 months. A statistically significant difference in postoperative infections was observed in patients with a history of previous cranial surgery who underwent unilateral compared to bilateral frontal sinus cranialization. CONCLUSION: These results suggest surgeons performing craniotomy or consulted intraoperatively for suspected frontal sinus breach should have a high suspicion for breached frontal sinus and a low threshold for frontal sinus cranialization. Furthermore, when performing frontal sinus cranialization, surgeons should consider performing bilateral, instead of unilateral, cranialization in patients with a history of previous craniotomy as bilateral cranialization was shown to decrease the risk of postoperative infection.

Sonolucent Cranial Implants: Cadaveric Study and Clinical Findings Supporting Diagnostic and Therapeutic Transcranioplasty Ultrasound.

BACKGROUND: Previously, sonographic evaluation of the intracranial contents was limited to intraoperative use following bone flap removal, with placement of the probe directly on the cortical surface or through a transsulcal tubular retractor. Cranioplasty with sonolucent implants may represent a postoperative window into the brain by allowing ultrasound to serve as a novel bedside imaging modality. The potential sonolucency of various commonly used cranial implant types was examined in this study. METHODS: A 3-phase study was comprised of cadaveric evaluation of transcranioplasty ultrasound (TCU) with cranioplasty implants of varying materials, intraoperative TCU during right-sided cranioplasty with clear implant made of poly-methyl-methacrylate (PMMA), and bedside TCU on postoperative day 5 after cranioplasty. RESULTS: The TCU through clear PMMA, polyether-ether-ketone, and opaque PMMA cranial implants revealed implant sonoluceny, in contrast to autologous bone and porous-polyethylene. Intraoperative ultrasound via the clear PMMA implant in a single patient revealed recognizable ventricular anatomy. Furthermore, postoperative bedside ultrasound in the same patient revealed comparable ventricular anatomy and a small epidural fluid collection corresponding to that visualized on an axial computed tomography scan. CONCLUSION: Sonolucent cranial implants, such as those made of clear PMMA, hold great promise for enhanced diagnostic and therapeutic applications previously limited by cranial bone. Furthermore, as functional cranial implants are manufactured with implantable devices housed within clear PMMA, the possibility of utilizing ultrasound for real-time surveillance of intracranial pathology becomes much more feasible.

Transcranioplasty Ultrasound Through a Sonolucent Cranial Implant Made of Polymethyl Methacrylate: Phantom Study Comparing Ultrasound, Computed Tomography, and Magnetic Resonance Imaging.

BACKGROUND: Current methods of transcranial diagnostic ultrasound imaging are limited by the skull's acoustic properties. Craniotomy, craniectomy, and cranioplasty procedures present opportunities to circumvent these limitations by substituting autologous bone with synthetic cranial implants composed of sonolucent biomaterials. OBJECTIVE: This study examined the potential to image the brain using transcranioplasty ultrasound (TCU) through a sonolucent cranial implant. MATERIALS AND METHODS: A validated adult brain phantom was imaged using computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound without an implant. Next, for experimental comparison, TCU was performed through a sonolucent implant composed of clear polymethyl methacrylate. RESULTS: All imaging modalities successfully revealed elements of the brain phantom, including the bilateral ventricular system, the falx cerebri, and a deep hyperdense mass representing a brain tumor or hematoma. In addition, ultrasound images were captured which closely resembled axial images obtained with both CT and MRI. CONCLUSION: The results obtained in this first-ever, preclinical, phantom study suggest TCU is now a viable immediate and long-term diagnostic imaging modality deserving of further clinical investigation.

Stereotactic radiosurgery vs. fractionated radiotherapy for tumor control in vestibular schwannoma patients: a systematic review.

OBJECTIVE: Repeated controlled studies have revealed that stereotactic radiosurgery is better than microsurgery for patients with vestibular schwannoma (VS) <3 cm in need of intervention. In this systematic review we aimed to compare results from single-fraction stereotactic radiosurgery (SRS) to fractionated stereotactic radiotherapy (FSRT) for patients with VS. DATA SOURCES AND ELIGIBILITY CRITERIA: We systematically searched MEDLINE, Web of Science, Embase and Cochrane and screened relevant articles for references. Publications from 1995 through 2014 with a minimum of 50 adult (>18 years) patients with unilateral VS, followed for a median of >5 years, were eligible for inclusion. After screening titles and abstracts of the 1094 identified articles and systematically reviewing 98 of these articles, 19 were included. INTERVENTION: Patients with unilateral VS treated with radiosurgery were compared to patients treated with fractionated stereotactic radiotherapy. RESULTS: No randomized controlled trial (RCT) was identified. None of the identified controlled studies comparing SRS with FSRT were eligible according to the inclusion criteria. Nineteen case series on SRS (n = 17) and FSRT (n = 2) were included in the systematic review. Loss of tumor control necessitating a new VS-targeted intervention was found in an average of 5.0% of the patients treated with SRS and in 4.8% treated with FSRT. Mean deterioration ratio for patients with serviceable hearing before treatment was 49% for SRS and 45% for FSRT, respectively. The risk for facial nerve deterioration was 3.6% for SRS and 11.2% for FSRT and for trigeminal nerve deterioration 6.0% for SRS and 8.4% for FSRT. Since these results were obtained from case series, a regular meta-analysis was not attempted. CONCLUSION: SRS and FSRT are both noninvasive treatment alternatives for patients with VS with low rates of treatment failure in need of rescue therapy. In this selection of patients, the progression-free survival rates were on the order of 92-100% for both treatment options. There is a lack of high-quality studies comparing radiation therapy alternatives for patients with VS. Finally, 19 articles reported long-term tumor control after SRS, while only 2 articles reported long-term FSRT results, making effect estimates more uncertain for FSRT.

Conservative management for pediatric patients with chiari 1 anomaly: A retrospective study.

OBJECTIVE: To better understand the natural history of non-surgical management of chiari 1 anomaly. PATIENTS AND METHODS: After obtaining approval of the institutional review board, medical records and radiological exams of patients treated for CM1 at our institution between the years 2010 and 2016 were reviewed. Twenty-nine patients total were included in our study. RESULTS: The average age of our patient population was 8.5 years old at the time of diagnosis. The average tonsillar herniation on first MRI was 9.4 mm (+/- 4.6) and the average tonsillar herniation on second MRI was 10.4 mm (+/- 4.8). The average follow up time of our sample of patients was 26 months. Of the 29 patients in our study 9 (31 %) had symptomatic presentation. Interestingly, four of our patients (13.8 %) presented with epilepsy. CONCLUSIONS: Our findings support the previous work that nonoperative management is best in asymptomatic or mildly symptomatic chiari patients.

Paradoxical ventriculomegaly due to low-pressure hydrocephalus, a rare complication of the treatment of a trapped fourth ventricle: Case report.

In this paper, we describe the rare phenomena of descending transtentorial herniation and paradoxical ventriculomegaly due to low pressure hydrocephalus. This resulted as a complication of treatment in a 14year old male patient, who had undergone multiple ventriculo-peritoneal shunt placements for hydrocephalus after resection of pilocytic astrocytoma. We discuss the etiology of this rare complication and our strategy for treatment. We emphasize the need for strategic placement of programmable shunts to avoid over shunting and associated complications such as tentorial herniation.