Symptomatic Oculomotor Nerve Cyst in a 3-Year-Old Child: Case Report With Emphasis on Surgical Management

BACKGROUND AND IMPORTANCE Third nerve palsies in the pediatric population are most commonly caused by trauma, tumors, or vascular abnormalities. Cystic oculomotor nerve neuropathies, however, are rare. We report the case of a symptomatic cyst along and within the oculomotor nerve, which has not been described previously. CLINICAL PRESENTATION Here, we report a case of a 3-yr-old girl presenting with a progressive painless oculomotor nerve palsy. A magnetic resonance imaging revealed a cystic formation along the cisternal and cavernous course of the nerve. Due to lack of alternative treatment options, surgery was offered. Intraoperative direct nerve stimulation allowed for identification of a non-functional part of the cyst wall and open fenestration and biopsy were executed. Histopathology revealed neuritis. Serology was negative for various pathogens. The oculomotor palsy rapidly resolved. At a follow-up 5 yr after surgery, the girl is asymptomatic and the cisternal part of the cyst remains collapsed. CONCLUSION This is the first report of a symptomatic cyst along and within the oculomotor nerve treated effectively with open fenestration and decompression highlighting the importance of intraoperative neuromonitoring in cranial nerve surgery. Uncertainty remains regarding the etiology of this disease.

Case Series: Cystic Brain Metastases Managed With Reservoir Placement and Stereotactic Radiosurgery

BACKGROUND Stereotactic radiosurgery (SRS) has become one of the mainstays of treatment for patients with metastatic brain tumors. However, metastatic tumors with a large cystic component often exceed the size limit for safe and effective SRS. In such cases, surgical resection may not be the preferred first method of treatment, due to tumor location, patient co-morbidities, and patient preference. In these patients, volume reduction by cyst aspiration (CA) followed by SRS may be a viable alternative treatment option. OBJECTIVE To present the treatment of patients with cystic metastases using reservoir placement followed by SRS. METHODS Nine patients were treated with this method. We performed reservoir insertion for the aspiration of cystic component in each patient and followed that with outpatient SRS. RESULTS Mean overall volume reduction from this treatment method was 78.5%. Mean volume reduction from the CA alone was 59.8%, and after SRS, a further 66.6%, accounting for some cyst reaccumulation between the time of surgery and SRS. Repeat reservoir aspiration was done a total of 10 times in 5 patients. Our study showed local tumor control in 7 of 9 patients (77.8%), while 2 patients required later surgical resection of their tumors. CONCLUSION CA with reservoir placement followed by SRS is a good option for patients with large cystic brain metastases. The reservoir allows for repeat aspiration if needed. Catheter placement at the center of the cyst, and SRS within 2 to 3 wk of surgery, can maximize the likelihood of a successful outcome.

Improving Neurosurgery Resident Microdissection Through Placental Simulation

ABSTRACT Prior work has shown that the human placenta is an available and realistic model for microdissection simulation. We sought to find a measurable improvement in the technical skills of neurosurgical residents with deliberate practice of microdissection tasks using a placental model. Postgraduate year (PGY) 1 to 3 neurosurgery residents were consented. A 1-min video of each participant's baseline skills skeletonizing placental vessels was recorded. Participants underwent 10 practice sessions with intermittent informal feedback for 30-60 min over 18 mo. Another 1-min video was recorded following the 10th dissection. The videos were blinded and assessed by 3 board eligible or certified microsurgical neurosurgeons using a modified Objective Structured Assessment of Aneurysm Clipping Skills. Performance was compared via t-testing among four domains: instrument handling, time flow and forward planning, quality of dissection, and respect for tissue. Microdissection, instrument handling, and quality of dissection were significantly improved after deliberate practice with the placental simulator (P < .05). Improvement was seen in time flow and forward planning and respect for tissue; however, this failed to be significant. Subjectively, residents expressed enjoyment performing the exercise. They also expressed a desire for demonstrations or videos to watch before practice sessions. The placental simulation model provides microsurgical skill development with minimal deliberate practice sessions. Practice exercises are favorably regarded and interest in continuing them is strong by residents. Residents expressed a desire to make the dissection more deliberate with demonstration, breakdown of steps, and mimicry, which could improve the effectiveness and enjoyment of the skills session.

Magnetic Resonance Imaging Mapping of Brain Tumor Burden: Clinical Implications for Neurosurgical Management: Case Report

ABSTRACT BACKGROUND AND IMPORTANCE Distinction of brain tumor progression from treatment effect on postcontrast magnetic resonance imaging (MRI) is an ongoing challenge in the management of brain tumor patients. A newly emerging MRI biomarker called fractional tumor burden (FTB) has demonstrated the ability to spatially distinguish high-grade brain tumor from treatment effect with important implications for surgical management and pathological diagnosis. CLINICAL PRESENTATION A 58-yr-old male with glioblastoma was treated with standard concurrent chemoradiotherapy (CRT) after initial resection. Throughout follow-up imaging, the distinction of tumor progression from treatment effect was of concern. The surgical report from a redo resection indicated recurrent glioblastoma, while the tissue sent for pathological diagnosis revealed no tumor. Presurgical FTB maps confirmed the spatial variation of tumor and treatment effect within the contrast-agent enhancing lesion. Unresected lesion, shown to be an active tumor on FTB, was the site of substantial tumor growth postresection. CONCLUSION This case report introduces the idea that a newly developed MRI biomarker, FTB, can provide information of tremendous benefit for surgical management, pathological diagnosis as well as subsequent treatment management decisions in high-grade glioma.

Active Cerebrospinal Fluid Exchange System for Treatment of Pyogenic Ventriculitis

ABSTRACT BACKGROUND Despite recent advances in antibiotic treatment, pyogenic ventricular brain infections are still associated with adverse clinical outcome in 80% of affected patients and mortality rates approaching 60%. The limitation of antibiotic penetration into the cerebrospinal fluid (CSF) challenges the treatment. Intrathecal treatment remains an option for adjunctive therapy to intravenous (iv) antibiotics when the iv therapy fails to sterilize the CFS. Current treatment options do not allow for changing the CSF composition without adversely affecting intracranial pressure (ICP) and power of hydrogen (pH). OBJECTIVE To investigate if CSF composition exchange has impact on ventriculitis patients. METHODS We report 2 cases with pyogenic ventriculitis treated with a new intracranial active fluid exchange system that consists of a dual-lumen catheter to facilitate irrigation and drainage coupled with an intelligent digital pump. RESULTS This new technique allowed us to change the composition of CSF to an antibiotic-consisted fluid. This resulted in the ability to directly modify the concentration of the targeted antibiotics in the CSF, while simultaneously removing bacterial mass without harming brain tissue and controlling ICP and pH. CONCLUSION Our reported experience shows that drainage of purulent fluid caused by healthcare-associated ventriculitis or meningitis is now possible without harming brain tissue and ICP while also changing the composition of CSF to an antibiotic-consisted fluid. Actively removing pus and altering CSF in this manner had an impact on infection treatment and antibiotic penetration. Further cases are needed to confirm that our treatment algorithm is correctly tailored to assist clinicians in reliably treating this catastrophic condition.

Tissue Engineering and Regenerative Medicine Cranioplasty Using Polycaprolactone-Tricalcium Phosphate: Management and Treatment Outcomes

ABSTRACT BACKGROUND Cranioplasty is a procedure commonly performed as the next step in management for patients with decompressive craniectomy. It is commonly associated with complications that might result in implant failure and reoperation. Tissue engineering and regenerative medicine (TERM) involve the development of biological substitutes that restore tissue function and regrow and replace damaged tissues. TERM is a potential solution that might allow for improved long-term outcomes in cranioplasty. OBJECTIVE To present a case series that describes the management and treatment outcomes of using TERM in cranioplasty, using polycaprolactone-tricalcium phosphate (PCL-TCP) implants in 2 patients. METHODS In 2 young adults, large bone defects of the skull following decompressive craniectomy were reconstructed using patient-specific implants manufactured from PCL-TCP. Bone marrow aspirate was used as autologous biologic that incorporates stem cell and growth factors into the implant. RESULTS Both patients recovered without any complications following surgery. Physical examination shows favorable healing outcomes with the defect area having a hard texture upon palpation. Postoperative imaging performed at 8 and 20 months for each patient, respectively, demonstrated ossification over the defect area. CONCLUSION Satisfactory bone growth is seen with TERM cranioplasty. The PCL-TCP implant is a novel and recommendable alternative to currently available patient-specific implants used in cranioplasty. TERM cranioplasty is the potential solution to the quest of finding the ideal cranioplasty implant.

Local 3-Dimensional Printing of a Calvarium-Anchored Ventricular Catheter Occlusion Device

ABSTRACT Three-dimensional (3D)-printed objects have been incorporated into many surgical specialties for various purposes. These devices can be customized and used as implants or surgical instruments. This study describes the use of a 3D-printed device that eliminates the need for a surgical assistant to occlude and retain the intracranial catheter during ventriculoperitoneal shunt creation and revision. After we identified design considerations and solutions, we modeled the device dimensions using computer-aided design software. Prototypes were 3D printed using stereolithography. Iterative design improvements were tested on cadaveric cranial samples. A final design was established, prepared by the in-hospital sterile processing department, and deployed successfully for clinical use. The design process for 3D-printed surgical instruments can produce straightforward idea-to-prototype pipelines. Because 3D-printed devices are easily duplicated and modified, small adjustments and new models can be developed, printed, and tested in a short time span.