IU Indianapolis ScholarWorks :: Browsing by Author "Bohnstedt, Bradley N."

Browsing by Author "Bohnstedt, Bradley N."

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Anterior communicating artery complex aneurysms: anatomic characteristics as predictors of surgical outcome in 300 cases
(Elsevier, 2018) Bohnstedt, Bradley N.; Conger, Andrew R.; Edwards, John; Ziemba-Davis, Mary; Edwards, Gary; Brom, Jacqueline; Shah, Kushal; Cohen-Gadol, Aaron A.; Neurological Surgery, School of Medicine
OBJECTIVE Anterior communicating artery (ACoA) complex aneurysms are challenging to treat microsurgically. The authors report their experience with microsurgical treatment of ACoA aneurysms and examine the anatomic characteristics of these aneurysms as predictors of outcome. METHODS The authors queried their institution’s aneurysm database for records of consecutive patients treated for ACoA aneurysms via microsurgical clip ligation. Data included patient demographics and clinical/radiographic presentation characteristics as well as operative techniques. Glasgow outcome scores (GOS) at hospital discharge and 6-month as well as 1-year follow-up were analyzed. RESULTS Of 319 ACoA aneurysms that underwent treatment, 259 were ruptured and 60 were unruptured. Average GOS at 1-year follow-up for all patients was 4.6. Average GOS for patients with ruptured aneurysms correlated with Hunt and Hess grade at presentation, presence of frontal hemorrhages, and need for multiple clips during surgery. Notably, 142 (44.5%) of aneurysms originated mainly from the ACoA artery; 12 (3.8%) primarily from the A1 branch; 3 (0.9%) from the A2 branch; and 162 (50.8%) from the A1/A2 junction. Aneurysm projection was superior in 118 (37%), inferior in 106 (33.2%), anterior in 88 (27.6%), and posterior in 7 (2.2%). Patients with aneurysms originating from the A1 segment had worse outcomes. Posteriorly-projecting aneurysms were more likely to be unruptured and larger than other aneurysm configurations. CONCLUSIONS The aneurysm’s exact location in relation to the adjacent neurovascular structures is potentially predictive of outcomes in the microsurgical treatment of ACoA aneurysms.
Blood Supply to the Human Spinal Cord. II. Imaging and Pathology
(Wiley, 2015-01) Bosmia, Anand N.; Tubbs, R. Shane; Hogan, Elizabeth; Bohnstedt, Bradley N.; DeNardo, Andrew J.; Loukas, Marios; Cohen-Gadol, Aaron A.; Department of Neurological Surgery, IU School of Medicine
The blood supply of the spinal cord is a complex system based on multilevel sources and anastomoses. Diseases often affect this vascular supply and imaging has been developed that better investigates these structures. The authors review the literature regarding pathology and imaging modalities for the blood supply of the spinal cord. Knowledge of the disease processes and imaging modalities used to investigate these arterial lesions of the spinal cord will assist the clinician when treating patients with spinal cord lesions.
Efficacy of postoperative seizure prophylaxis in intra-axial brain tumor resections
(Springer, 2014) Ansari, Shaheryar F.; Bohnstedt, Bradley N.; Perkins, Susan M.; Althouse, Sandra K.; Miller, James C.; Neurological Surgery, School of Medicine
The effectiveness of seizure prophylaxis in controlling postoperative seizures following craniotomy for tumor resection is unclear. Most patients are seizure-free before surgery. To prevent seizures, it is common to treat tumor craniotomy patients postoperatively with an antiepileptic drug (AED). The authors retrospectively analyzed seizure occurrence with and without postoperative prophylactic AEDs. Between 2005 and 2011 at the authors' institution, 588 patients underwent craniotomy for brain tumors and were screened. Data on seizures, AED use, histopathology, comorbidities, complications, and follow-up were collected. Exclusion criteria included lack of follow-up data, previous operation, preoperative seizures, or preoperative AED prophylaxis. The incidence of postoperative seizures in patients with and without prophylactic AEDs was compared using logistic regression analysis. A total of 202 patients (50.5% female) were included. The most common tumor diagnosis was metastasis (42.6%). Of the 202 patients, 66.3% were prescribed prophylactic AED after surgery. Forty-six of 202 (22.8%) suffered a postoperative seizure. The odds of seizure for patients on prophylactic AED was 1.62 times higher than those not on AED (p = 0.2867). No difference was found in seizure occurrence between patients with glioblastoma multiforme compared with other tumor types (odds ratio 1.75, p = 0.1468). No difference was found in time-to-seizure between the two groups (hazard ratio 1.38, p = 0.3776). These data show no statistically significant benefit to prophylactic postoperative AED and a nonsignificant trend for increased seizure risk with AEDs. A randomized, placebo-controlled trial is needed to clarify the benefit of postoperative AED use for brain tumor resection.
Endovascular treatment of penetrating nail gun injury of the cervical spine and vertebral artery: a case report
(The Korean Society of Traumatology, 2022) Christodoulides, Alexei; Mitchell, Scott; Bohnstedt, Bradley N.; Neurological Surgery, School of Medicine
In this report, we present a case of high cervical penetrating trauma with vertebral artery injury and outline preprocedural, procedural, and postprocedural considerations with recommendations for the treatment of similar injuries. Management involves multiple imaging modalities, including X-ray imaging, computed tomography, computed tomography angiography, magnetic resonance imaging, and catheter angiography. We recommend endovascular treatment of these injuries when possible, based on the improved ability to achieve proximal and distal control and manage hemorrhage risk.
Intracranial chordoma presenting as acute hemorrhage in a child: Case report and literature review
(Wolters Kluwer, 2015-04-20) Moore, Kenneth A.; Bohnstedt, Bradley N.; Shah, Sanket U.; Abdulkader, Marwah M.; Bonnin, Jose M.; Ackerman, Laurie L.; Shaikh, Kashif; Kralik, Stephen F.; Shah, Mitesh V.; Department of Neurological Surgery, IU School of Medicine
BACKGROUND: Chordomas are rare, slow-growing malignant neoplasms derived from remnants of the embryological notochord. Pediatric cases comprise only 5% of all chordomas, but more than half of the reported pediatric chordomas are intracranial. For patients of all ages, intracranial chordomas typically present with symptoms such as headaches and progressive neurological deficits occurring over several weeks to many years as they compress or invade local structures. There are only reports of these tumors presenting acutely with intracranial hemorrhage in adult patients. CASE DESCRIPTION: A 10-year-old boy presented with acute onset of headache, emesis, and diplopia. Head computed tomography and magnetic resonance imaging of brain were suspicious for a hemorrhagic mass located in the left petroclival region, compressing the ventral pons. The mass was surgically resected and demonstrated acute intratumoral hemorrhage. Pathologic examination was consistent with chordoma. CONCLUSION: There are few previous reports of petroclival chordomas causing acute intracranial hemorrhage. To the authors' knowledge, this is the first case of a petroclival chordoma presenting as acute intracranial hemorrhage in a pediatric patient. Although uncommon, it is important to consider chordoma when evaluating a patient of any age presenting with a hemorrhagic lesion of the clivus.
Load-dependent collagen fiber architecture data of representative bovine tendon and mitral valve anterior leaflet tissues as quantified by an integrated opto-mechanical system
(Elsevier, 2020-02) Jett, Samuel V.; Hudson, Luke T.; Baumwart, Ryan; Bohnstedt, Bradley N.; Mir, Arshid; Burkhart, Harold M.; Holzapfel, Gerhard A.; Wu, Yi; Lee, Chung-Hao; Neurological Surgery, School of Medicine
The data presented in this article provide load-dependent collagen fiber architecture (CFA) of one representative bovine tendon tissue sample and two representative porcine mitral valve anterior leaflet tissues, and they are stored in a MATLAB MAT-file format. Each dataset contains: (i) the number of pixel points, (ii) the array of pixel's x- and y-coordinates, (iii) the three acquired pixel intensity arrays, and (iv) the Delaunay triangulation for visualization purpose. This dataset is associated with a companion journal article, which can be consulted for further information about the methodology, results, and discussion of the opto-mechanical characterization of the tissue's CFA's (Jett etal. [1]).
Management of Type III Occipital Condyle Fractures
(MDPI, 2024-12-15) Kwon, Jae Hyun; Chinthala, Anoop Sai; Arnold, Jonathan C.; Witten, Andrew J.; Bohnstedt, Bradley N.; Neurological Surgery, School of Medicine
Background/Objectives: Occipital condyle fractures (OCFs) can be seen in around 4-19% of patients who suffer from cervical spine trauma. Anderson and Montesano system type III OCFs, which are avulsion fractures, are potentially unstable and operative. This study evaluates the management of type III OCFs at our institution over a 22-year period. Methods: This retrospective study reviewed all cases of type III OCFs at our institution from July 2001 to March 2023, identified via imaging reports. Using the in-house radiology imaging informatics system "Doris" (Dig Our Radiology Information System), reports containing the terms subluxation, avulsion, unstable, or type 3/III with occipital condyle, occipital condylar, occipital fx, or occipital fracture were collected. We also searched for Montesano type III/3 fracture. Electronic medical records were used to collect clinical and demographic data. Patients evaluated by the neurosurgical team with at least 1 month of follow-up were included in the analysis. Results: A total of 563 patients were identified with type III OCFs. A total of 56 patients met the inclusion criteria. The majority (91%, 51/56) were treated conservatively with cervical orthosis. A small subset (8.9%, 5/56) underwent occipito-cervical fusion. Three had concomitant unstable C1 fractures, while the other two had significant coronal deformity associated with their type III OCF. Conclusions: At our institution, type III OCFs are predominantly managed with cervical orthosis. Only those with an associated malalignment of the occipito-cervical joint underwent fusion. These findings suggest that most type III OCFs can be treated conservatively with orthosis once stability is confirmed with an upright radiograph.
A pilot study on biaxial mechanical, collagen microstructural, and morphological characterizations of a resected human intracranial aneurysm tissue
(Springer Nature, 2021-02-10) Laurence, Devin W.; Homburg, Hannah; Yan, Feng; Tang, Qinggong; Fung, Kar‑Ming; Bohnstedt, Bradley N.; Holzapfel, Gerhard A.; Lee, Chung‑Hao; Neurological Surgery, School of Medicine
Intracranial aneurysms (ICAs) are focal dilatations that imply a weakening of the brain artery. Incidental rupture of an ICA is increasingly responsible for significant mortality and morbidity in the American’s aging population. Previous studies have quantified the pressure-volume characteristics, uniaxial mechanical properties, and morphological features of human aneurysms. In this pilot study, for the first time, we comprehensively quantified the mechanical, collagen fiber microstructural, and morphological properties of one resected human posterior inferior cerebellar artery aneurysm. The tissue from the dome of a right posterior inferior cerebral aneurysm was first mechanically characterized using biaxial tension and stress relaxation tests. Then, the load-dependent collagen fiber architecture of the aneurysm tissue was quantified using an in-house polarized spatial frequency domain imaging system. Finally, optical coherence tomography and histological procedures were used to quantify the tissue’s microstructural morphology. Mechanically, the tissue was shown to exhibit hysteresis, a nonlinear stress-strain response, and material anisotropy. Moreover, the unloaded collagen fiber architecture of the tissue was predominantly aligned with the testing Y-direction and rotated towards the X-direction under increasing equibiaxial loading. Furthermore, our histological analysis showed a considerable damage to the morphological integrity of the tissue, including lack of elastin, intimal thickening, and calcium deposition. This new unified characterization framework can be extended to better understand the mechanics-microstructure interrelationship of aneurysm tissues at different time points of the formation or growth. Such specimen-specific information is anticipated to provide valuable insight that may improve our current understanding of aneurysm growth and rupture potential.
Posterior Interhemispheric Transfalcine Transprecuneus Approach for Microsurgical Resection of Peri-Atrial Lesions: Indications, Technique, and Outcomes
(2015-10) Bohnstedt, Bradley N.; Kulwin, Charles; Shah, Mitesh; Cohen-Gadol, Aaron A.; Department of Neurological Surgery, IU School of Medicine
OBJECT Surgical exposure of the peritrigonal or periatrial region has been challenging due to the depth of the region and overlying important functional cortices and white matter tracts. The authors demonstrate the operative feasibility of a contralateral posterior interhemispheric transfalcine transprecuneus approach (PITTA) to this region and present a series of patients treated via this operative route. METHODS Fourteen consecutive patients underwent the PITTA and were included in this study. Pre- and postoperative clinical and radiological data points were retrospectively collected. Complications and extent of resection were reviewed. RESULTS The mean age of patients at the time of surgery was 39 years (range 11–64 years). Six of the 14 patients were female. The mean duration of follow-up was 4.6 months (range 0.5–19.6 months). Pathology included 6 arteriovenous malformations, 4 gliomas, 2 meningiomas, 1 metastatic lesion, and 1 gray matter heterotopia. Based on the results shown on postoperative MRI, 1 lesion (7%) was intentionally subtotally resected, but ≥ 95% resection was achieved in all others (93%) and gross-total resection was accomplished in 7 (54%) of 13. One patient (7%) experienced a temporary approach-related complication. At last follow-up, 1 patient (7%) had died due to complications of his underlying malignancy unrelated to his cranial surgery, 2 (14%) demonstrated a Glasgow Outcome Scale (GOS) score of 4, and 11 (79%) manifested a GOS score of 5. CONCLUSIONS Based on this patient series, the contralateral PITTA potentially offers numerous advantages, including a wider, safer operative corridor, minimal need for ipsilateral brain manipulation, and better intraoperative navigation and working angles.
Shape Memory Polymer-Based Endovascular Devices: Design Criteria and Future Perspective
(MDPI, 2022-06-21) Pineda-Castillo, Sergio A.; Stiles, Aryn M.; Bohnstedt, Bradley N.; Lee, Hyowon; Liu, Yingtao; Lee, Chung-Hao; Neurological Surgery, School of Medicine
Devices for the endovascular embolization of intracranial aneurysms (ICAs) face limitations related to suboptimal rates of lasting complete occlusion. Incomplete occlusion frequently leads to residual flow within the aneurysm sac, which subsequently causes aneurysm recurrence needing surgical re-operation. An emerging method for improving the rates of complete occlusion both immediately after implant and in the longer run can be the fabrication of patient-specific materials for ICA embolization. Shape memory polymers (SMPs) are materials with great potential for this application, owing to their versatile and tunable shape memory properties that can be tailored to a patient's aneurysm geometry and flow condition. In this review, we first present the state-of-the-art endovascular devices and their limitations in providing long-term complete occlusion. Then, we present methods for the fabrication of SMPs, the most prominent actuation methods for their shape recovery, and the potential of SMPs as endovascular devices for ICA embolization. Although SMPs are a promising alternative for the patient-specific treatment of ICAs, there are still limitations that need to be addressed for their application as an effective coil-free endovascular therapy.

Browsing by Author "Bohnstedt, Bradley N."

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