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Gabriel Zada, Vance L. Fredrickson and Bozena B. Wrobel

Meningiomas are the most prevalent primary intracranial tumor, with 3%–10% arising from the tuberculum sellae. Optimal management consists of total microsurgical resection with preservation of surrounding structures. The authors present a 64-year-old woman with progressive bilateral vision loss, including visual acuity deficits and bitemporal hemianopsia. MRI revealed a 2-cm tuberculum sellae meningioma causing optic apparatus compression. An extended endoscopic endonasal transtuberculum approach was utilized for gross-total resection, including microdissection of tumor from the optic chiasm and infundibulum. Closure was performed with multilayer tensor fascia lata autograft and a pedicled nasal-septal flap. The patient’s postoperative exam showed visual improvement and normal pituitary function.

The video can be found here: https://youtu.be/ZfNB_rhlyeI.

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Martin H. Pham, Joshua Bakhsheshian, Patrick C. Reid, Ian A. Buchanan, Vance L. Fredrickson and John C. Liu

OBJECTIVE

Freehand placement of C2 instrumentation is technically challenging and has a learning curve due the unique anatomy of the region. This study evaluated the accuracy of C2 pedicle screws placed via the freehand technique by neurosurgical resident trainees.

METHODS

The authors retrospectively reviewed all patients treated at the LAC+USC Medical Center undergoing C2 pedicle screw placement in which the freehand technique was used over a 1-year period, from June 2016 to June 2017; all procedures were performed by neurosurgical residents. Measurements of C2 were obtained from preoperative CT scans, and breach rates were determined from coronal reconstructions on postoperative scans. Severity of breaches reflected the percentage of screw diameter beyond the cortical edge (I = < 25%; II = 26%–50%; III = 51%–75%; IV = 76%–100%).

RESULTS

Neurosurgical residents placed 40 C2 pedicle screws in 24 consecutively treated patients. All screws were placed by or under the guidance of Pham, who is a postgraduate year 7 (PGY-7) neurosurgical resident with attending staff privileges, with a PGY-2 to PGY-4 resident assistant. The authors found an average axial pedicle diameter of 5.8 mm, axial angle of 43.1°, sagittal angle of 23.0°, spinal canal diameter of 25.1 mm, and axial transverse foramen diameter of 5.9 mm. There were 17 screws placed by PGY-2 residents, 7 screws placed by PGY-4 residents, and 16 screws placed by the PGY-7 resident. The average screw length was 26.0 mm, with a screw diameter of 3.5 mm or 4.0 mm. There were 7 total breaches (17.5%), of which 4 were superior (10.0%) and 3 were lateral (7.5%). There were no medial breaches. The breaches were classified as grade I in 3 cases (42.9%), II in 3 cases (42.9%), III in 1 case (14.3%), and IV in no cases. There were 3 breaches that occurred via placement by a PGY-2 resident, 3 breaches by a PGY-4 resident, and 1 breach by the PGY-7 resident. There were no clinical sequelae due to these breaches.

CONCLUSIONS

Freehand placement of C2 pedicle screws can be done safely by neurosurgical residents in early training. When breaches occurred, they tended to be superior in location and related to screw length choice, and no breaches were found to be clinically significant. Controlled exposure to this unique anatomy is especially pertinent in the era of work-hour restrictions.

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Mohamad Bydon, Vance Fredrickson, Rafael De la Garza-Ramos, Yiping Li, Ronald A. Lehman Jr., Gregory R. Trost and Ziya L. Gokaslan

Sacral fractures are uncommon lesions and most often the result of high-energy trauma. Depending on the fracture location, neurological injury may be present in over 50% of cases. In this article, the authors conducted a comprehensive literature review on the epidemiology of sacral fractures, relevant anatomy of the sacral and pelvic region, common sacral injuries and fractures, classification systems of sacral fractures, and current management strategies. Due to the complex nature of these injuries, surgical management remains a challenge for the attending surgeon. Few large-scale studies have addressed postoperative complications or long-term results, but current evidence suggests that although fusion rates are high, long-term morbidity, such as residual pain and neurological deficits, persists for many patients.

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Eisha A. Christian, Joshua Bakhsheshian, Ben A. Strickland, Vance L. Fredrickson, Ian A. Buchanan, Martin H. Pham, Andrew Cervantes, Michael Minneti, Bozena B. Wrobel, Steven Giannotta and Gabriel Zada

OBJECTIVE

Competency in endoscopic endonasal approaches (EEAs) to repair high-flow cerebrospinal fluid (CSF) leaks is an essential component of the neurosurgical training process. The objective of this study was to demonstrate the feasibility of a simulation model for EEA repair of anterior skull base CSF leaks.

METHODS

Human cadaveric specimens were utilized with a perfusion system to simulate a high-flow CSF leak. Neurological surgery residents (postgraduate year 3 or greater) performed a standard EEA to repair a CSF leak using a combination of fat, fascia lata, and pedicled nasoseptal flaps. A standardized 5-point Likert questionnaire was used to assess the knowledge gained, techniques learned, degree of safety, benefit of CSF perfusion during repair, and pre- and posttraining confidence scores.

RESULTS

Intrathecal perfusion of fluorescein-infused saline into the ventricular/subarachnoid space was successful in 9 of 9 cases. The addition of CSF reconstitution offered the residents visual feedback for confirmation of intraoperative CSF leak repair. Residents gained new knowledge and a realistic simulation experience by rehearsing the psychomotor skills and techniques required to repair a CSF leak with fat and fascial grafts, as well as to prepare and rotate vascularized nasoseptal flaps. All trainees reported feeling safer with the procedure in a clinical setting and higher average posttraining confidence scores (pretraining 2.22 ± 0.83, posttraining 4.22 ± 0.44, p < 0.001).

CONCLUSIONS

Perfusion-based human cadaveric models can be utilized as a simulation training model for repairing CSF leaks during EEA.

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Michelle Lin, Michelle A. Wedemeyer, Daniel Bradley, Daniel A. Donoho, Vance L. Fredrickson, Martin H. Weiss, John D. Carmichael and Gabriel Zada

OBJECTIVE

Rathke’s cleft cysts (RCCs) are benign epithelial lesions of the sellar region typically treated via a transsphenoidal approach with cyst fenestration and drainage. At present, there is limited evidence to guide patient selection for operative treatment. Furthermore, there is minimal literature describing factors contributing to cyst recurrence.

METHODS

The authors conducted a retrospective analysis of 109 consecutive cases of pathology-confirmed RCCs treated via a transsphenoidal approach at a single center from 1995 to 2016. The majority of cases (86.2%) involved cyst fenestration, drainage, and partial wall resection. Long-term outcomes were analyzed.

RESULTS

A total of 109 surgeries in 100 patients were included, with a mean follow-up duration of 67 months (range 3–220 months). The mean patient age was 44.6 years (range 12–82 years), and 73% were women. The mean maximal cyst diameter was 14.7 mm. Eighty-eight cases (80.7%) were primary operations, and 21 (19.3%) were reoperations. Intraoperative CSF leak repair was performed in 53% of cases and was more common in reoperation cases (71% vs 48%, p < 0.001). There were no new neurological deficits or perioperative deaths. Two patients (1.8%) developed postoperative CSF leaks. Transient diabetes insipidus (DI) developed in 24 cases (22%) and permanent DI developed in 6 (5.5%). Seven cases (6.4%) developed delayed postoperative hyponatremia. Of the 66 patients with preoperative headache, 27 (44.3%) of 61 reported postoperative improvement and 31 (50.8%) reported no change. Of 31 patients with preoperative vision loss, 13 (48.1%) reported subjective improvement and 12 (44.4%) reported unchanged vision. Initial postoperative MRI showed a residual cyst in 25% of cases and no evidence of RCC in 75% of cases. Imaging revealed evidence of RCC recurrence or progression in 29 cases (26.6%), with an average latency of 28.8 months. Of these, only 10 (9.2% of the total 109 cases) were symptomatic and underwent reoperation.

CONCLUSIONS

Transsphenoidal fenestration and drainage of RCCs is a safe and effective intervention for symptomatic lesions, with many patients experiencing improvement of headaches and vision. RCCs show an appreciable (although usually asymptomatic) recurrence rate, thereby mandating serial follow-up. Despite this, full RCC excision is typically not recommended due to risk of hypopituitarism, DI, and CSF leaks.