Ben A. Strickland

Radiofrequency lesioning through deep brain stimulation electrodes: A pilot study of lesion geometry and temperature characteristics

Deep brain stimulation (DBS) electrodes have been used effectively to perform radiofrequency lesions in the brain. This study aimed to characterize lesion geometry and peak tissue temperature achieved when lesioning through DBS electrodes. Fresh bovine liver was chosen for a medium as the tissue reliably changes color between 45 and 50 °C. Medtronic 3387 DBS electrodes (Medtronic Sofamor Danek, Inc., Memphis, TN, USA) and the Cosman G4 Radiofrequency Generator (Cosman Medical, Inc., Burlington, MA, USA) were used for lesioning. Bipolar lesions were created at currents between 25 mA and 100 mA for 60-120 seconds. Peak tissue temperature was monitored with Cosman disposable cordotomy electrode (LCED; Cosman Medical Inc.) and recorded. Photographic analysis of the lesions was performed. Tissue impedance ranged between 800-900 Ohms, and tissue temperature was maintained at 20 °C. With lesions at 25 mA for up to 120 seconds, maximal tissue temperature achieved was 36 °C. This correlated with no visible lesions. At 50 mA, maximal tissue temperature exceeded 100 °C, which was associated with tissue charring. Lesions created at 35 mA and 40 mA led to an increase in tissue temperature of 63 °C and 75 °C, respectively. Lesion size was highly reproducible, increasing from 4.5 mm × 7 mm at 35 mA, to 6 mm × 7.5mm at 50 mA. Preliminary analysis suggests that caution should be exerted in using lesion amplitudes exceeding 40 mA (at 800 Ohms), as peak tissue temperatures in vivo could exceed 100 °C. Further in vivo experiments with imaging correlates are needed to further test the safety of this technique.

Extracranial to intracranial bypass for the treatment of cerebral aneurysms in the pediatric population

Cerebral aneurysms are rare in the pediatric population, making a definitive treatment algorithm difficult. Microsurgical clipping is the first choice for treatment but is not always feasible, while high recurrence rates and radiation exposure make endovascular options less favorable. Extracranial-intracranial (EC-IC) bypass, though not commonly performed in the pediatric aneurysm population, has been reported in a small number of studies to be both safe and effective for the management of cerebral aneurysms. The authors present the case of a child with a distal middle cerebral artery (MCA) aneurysm in eloquent territory, successfully treated with a superficial temporal artery (STA) to MCA bypass and trapping. A review of the current literature on pediatric EC-IC bypass in the treatment of intracranial aneurysms is presented.

Factors influencing outcomes of the treatment of positional plagiocephaly in infants: a 7-year experience

OBJECTIVE Following institution of the Back to Sleep Campaign, the incidence of sudden infant death syndrome decreased while the prevalence of positional skull deformation increased dramatically. The management of positional deformity is controversial, and treatment recommendations and outcomes reporting are variable. The authors reviewed their institutional experience (2008-2014) with the treatment of positional plagiocephaly to explore factors associated with measured improvement. METHODS A retrospective chart review was conducted with risk factors and treatment for positional head shape deformity recorded. Univariate and multivariate analyses were used to assess the impact of these variables on the change in measured oblique diagonal difference (ODD) on head shape surface scanning pre- and posttreatment. RESULTS A total of 991 infants aged less than 1 year were evaluated for cranial positional deformity in a dedicated clinical program. The most common deformity was occipital plagiocephaly (69.5%), followed by occipital brachycephaly (18.4%) or a combination of both deformities (12.1%). Recommended treatment included repositioning (RP), physical therapy (PT) if indicated, or orthotic treatment with a customized cranial orthosis (CO) according to an age- and risk factor-dependent algorithm that the authors developed for this clinic. Of the 991 eligible patients, 884 returned for at least 1 follow-up appointment. A total of 552 patients were followed to completion of their treatment and had a full set of records for analysis: these patients had pre- and posttreatment 2D surface scanner evaluations. The average presenting age was 6.2 months (corrected for prematurity for treatment considerations). Of the 991 patients, 543 (54.8%) had RP or PT as first recommended treatment. Of these 543 patients, 137 (25.2%) transitioned to helmet therapy after the condition did not improve over 4-8 weeks. In the remaining cases, RP/PT had already failed before the patients were seen in this program, and the starting treatment recommendation was CO. At the end of treatment, the measured improvements in ODD were 36.7%, 33.5%, and 15.1% for patients receiving CO, RP/PT/CO, and RP/PT, respectively. Univariate analysis showed that sex, race, insurance, diagnosis, sleep position preference, torticollis history, and multiple gestation were not significantly associated with magnitude of ODD change during treatment. On multivariate analysis, corrected age at presentation and type of treatment received were significantly associated with magnitude of ODD change. Orthotic treatment corresponded with the largest ODD change, while the RP/PT group had the least change in ODD. Earlier age at presentation corresponded with larger ODD change. CONCLUSIONS Earlier age at presentation and type of treatment impact the degree of measured deformational head shape correction in positional plagiocephaly. This retrospective study suggests that treatment with a custom CO can result in more improvement in objective measurements of head shape.

Spinal Anaplastic Oligodendroglioma With Oligodendrogliomatosis: Molecular Markers and Management: Case Report

BACKGROUND AND IMPORTANCE Spinal cord oligodendrogliomas are rare tumors, with a reported incidence varying between 0.8% and 4.7% of all spinal cord tumors and just over 50 cases reported in the literature. Of these, only 9 cases are histologically defined as anaplastic oligodendrogliomas, with few having complete molecular characterization. The diffuse tumor spread that can occur along the subarachnoid space with secondary invasion of the leptomeninges is called oligodendrogliomatosis and is associated with poor outcome. CLINICAL PRESENTATION A 68-year-old man with a history of lumbar stenosis status after lumbar decompression presented with new-onset right lower-extremity weakness. Magnetic resonance imaging demonstrated an intramedullary lesion from T9 to T12. During an attempted diagnostic biopsy, numerous intradural intramedullary lesions not present on magnetic resonance imaging were observed. Tissue biopsy demonstrated a 1p/19q-codeleted anaplastic oligodendroglioma with diffuse oligodendrogliomatosis. Postoperative treatment included 39.2-Gy radiation over 22 fractions from T1 to the bottom of the thecal sac with a boost to the T9-T12 area, the primary site of disease, to a total dose of 43.2 Gy in 24 fractions, followed by adjuvant temozolomide at a dose of 200 mg/m on days 1 to 5 in a 28-day cycle. At the 1-year follow-up, the patient demonstrated moderate neurological improvement. CONCLUSION Management, prognosis, and use of molecular data in the decision-making algorithm for these patients are discussed, together with a review of all cases of primary intradural intramedullary spinal anaplastic oligodendrogliomas reported to date. Our study indicates that the combination of sequential treatment with radiation and temozolomide might provide a favorable outcome in the case of 1p/19q-codeleted spinal anaplastic oligodendrogliomas and that molecular analysis can be beneficial in guiding treatment strategies, although the impact of IDH mutations on these tumors is still unclear.

Perfusion-based human cadaveric specimen as a simulation training model in repairing cerebrospinal fluid leaks during endoscopic endonasal skull base surgery

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.

Endoscopic Endonasal Transsphenoidal Drainage of a Spontaneous Candida glabrata Pituitary Abscess

BACKGROUND Noniatrogenic pituitary abscess remains a rare clinical entity, and is the indication for surgery in <1% of transsphenoidal approaches. Correct diagnosis of this rare entity is often delayed. Without timely treatment, morbidity and mortality are high. Of the 200 cases reported to date, less than one-half have identified a causative organism. We report the second case of a pituitary abscess caused by Candida species, and also provide an intraoperative video showing the endoscopic management of this pathology. CASE DESCRIPTION A 33-year-old woman presented with headache, hypopituitarism, and vision loss in the setting of diabetic ketoacidosis, and was found to have multiple abscesses in the liver, lung, kidney, and uterus. Brain magnetic resonance imaging revealed a 15-mm cystic sellar mass with restricted diffusion. The patient underwent urgent evacuation of the abscess via an endoscopic endonasal transsphenoidal route, with obvious purulent material filling the sella, later identified as Candida glabrata. Antimicrobial therapy was refined appropriately, and she exhibited significant improvement in neurologic function, although endocrinopathy has persisted. CONCLUSIONS With timely management, including a combination of surgical drainage and appropriate antimicrobial therapy, neurologic outcomes are good in most cases of pituitary abscess; however, endocrinopathy often does not improve. Although most reported cases with identified causative organisms speciate bacteria, some cases are of fungal etiology and require different antimicrobial agents. This further underscores the importance of identifying the causative agent.

Running-to-Interrupted Microsuture Technique for Vascular Bypass

BACKGROUND The ideal suturing technique for microvascular anastomosis for neurosurgical bypass procedures remains a point of debate. Simple interrupted sutures are thought to possess higher long-term patency but require more time to place as compared to running sutures. OBJECTIVE To optimize the efficiency of microvascular anastomosis and limit brain ischemia time. METHODS The running-to-interrupted microsuture technique, a modification of the previously published spiral anastomosis, is described wherein loosely thrown running sutures are placed between 2 opposed anchor stitches. The loops are then serially cut and tied, resulting in efficiently placed interrupted stitches. This process is repeated on the opposite side to complete the anastomosis. RESULTS The running-to-interrupted microsuture technique is quickly learned, limits unnecessary microsurgical movements, and is employed by the senior author for a multitude of cerebral arterial bypass procedures. CONCLUSION This technical improvement can be adapted by any neurovascular surgeon to optimize microsurgical efficiency and limit anastomosis-related brain ischemia times.

Intraoperative Imaging for Vascular Lesions

Neurovascular surgery is a broad and challenging, yet exciting field within neurologic surgery. The neurovascular surgeon must be meticulous; because the brain and spinal cord are unforgiving to ischemic insults. Along with the pressures of this demanding subspecialty comes the potential to help patients recover from potentially devastating pathology to go on and lead normal, healthy lives. Several intraoperative imaging modalities are available to help maximize treatment success while reducing risk. This article reviews each of these modalities, including digital subtraction angiography, fluorescence angiography, Doppler ultrasonography, laser Doppler, laser speckle contrast imaging, neuronavigation, and neuroendoscopy.

Transblepharo-Preseptal Modified Orbitozygomatic Craniotomy for Treatment of Ruptured Aneurysm: 3-Dimensional Operative Video

Various supraorbital approaches to the anterior cranial fossa using a transciliary or supraciliary incision have been described. An orbitotomy is a valuable addition to the standard supraorbital keyhole approach offering an extended angle of exposure with minimal frontal lobe retraction. The transpalpebral approach is common in oculoplastic surgery and offers excellent cosmetic outcomes using the natural crease of the superior eyelid. This approach avoids risk of eyebrow alopecia and damage to the frontalis muscle or frontalis branches of the facial nerve. A transblepharo-preseptal or transpalpebral modified orbitozygomatic approach for the treatment of unruptured anterior circulation aneurysms has been reported. Our experience with this approach has been that it has potential to offer anterior skull base access and outcomes that are not inferior to traditional approaches for selected cases including ruptured anterior circulation aneurysms. Moreover, we believe this approach can provide excellent cosmetic results and could minimize surgical time and hospitalization stay. This 3-dimensional video presents the case of a 47-year-old female with sudden-onset headache and seizure (Video 1). She was found to have a subarachnoid hemorrhage resulting from rupture of a carotid terminus aneurysm. Considering the location and morphology of the aneurysm, as well as the patients eyelid anatomy, clip ligation via a transblepharo-preseptal modified orbitozygomatic craniotomy was recommended. Aneurysm clipping was uneventful, and postoperative imaging showed complete occlusion. The patient was discharged neurologically intact.

Extracranial-Intracranial Bypass for Treatment of Blister Aneurysms: Efficacy and Analysis of Complications Compared with Alternative Treatment Strategies

OBJECTIVE Blister aneurysms (BAs) represent a clinical challenge without a consensus treatment strategy. We report our institutions experience with BAs with an emphasis on the use of extracranial-to-intracranial (EC-IC) bypass. METHODS Seventeen patients with BAs (88% [15/17] ruptured) were treated with microsurgical techniques (5 clip wrappings, 4 clip ligations, 4 EC-IC bypasses and clip trappings, 2 internal carotid artery ligations [1 combined with clip wrapping], and 2 clip trappings). RESULTS Six of 17 patients experienced intraoperative ruptures. There were no intraoperative ruptures among the bypass cases and 75% (3/4) of patients achieved a good neurologic outcome. Further, a literature review was performed to identify all previously reported cases of BAs undergoing clip ligation, clip wrapping, EC-IC bypass/clip trapping, and endovascular therapies, encompassing 246 BA cases across 33 studies. Intraoperative ruptures occurred in 29% of clip ligations (23/79), 27.2% of clip wrappings (6/35), 16.1% of EC-IC bypasses (5/31), and 0% of endovascular treatments. Aneurysm recurrence occurred in 2.97% (3/101) with endovascular therapies to 0% with EC-IC bypass. Mortality was 8.8% for clip ligation/wrapping (10/114), 6.5% for EC-IC bypass (2/31), and 4.0% for endovascular treatments (4/101). CONCLUSIONS Endovascular interventions have a favorable procedural safety profile but high rates of retreatment for persistent filling or posttreatment aneurysmal growth. Clip ligation and clip wrapping techniques have lower retreatment rates but slightly higher intraoperative risk. EC-IC bypass can safely provide definitive aneurysm securement and should be considered as a first-line therapy for BAs at high-volume bypass centers.