A guide to selecting upper thoracic versus lower thoracic uppermost instrumented vertebra in adult spinal deformity correction.

PURPOSE: Operative treatment of adult spinal deformity (ASD) has been shown to improve patient health-related quality of life (HRQOL). Selection of the uppermost instrumented vertebra (UIV) in either the upper thoracic (UT) or lower thoracic (LT) spine is a pivotal decision with effects on operative and postoperative outcomes. This review overviews the multifaceted decision-making process for UIV selection in ASD correction. METHODS: PubMed was queried for articles using the keywords "uppermost instrumented vertebra", "upper thoracic", "lower thoracic", and "adult spinal deformity". RESULTS: Optimization of UIV selection may lead to superior deformity correction, better patient-reported outcomes, and lower risk of proximal junctional kyphosis (PJK) and failure (PJF). Patient alignment characteristics, including preoperative thoracic kyphosis, coronal deformity, and the magnitude of sagittal correction influence surgical decision-making when selecting a UIV, while comorbidities such as poor body mass index, osteoporosis, and neuromuscular pathology should also be taken in to account. Additionally, surgeon experience and resources available to the hospital may also play a role in this decision. Currently, it is incompletely understood whether postoperative HRQOLs, functional and radiographic outcomes, and complications after surgery differ between selection of the UIV in either the UT or LT spine. CONCLUSION: The correct selection of the UIV in surgical planning is a challenging task, which requires attention to preoperative alignment, patient comorbidities, clinical characteristics, available resources, and surgeon-specific factors such as experience.

Accumulation of non-outer segment proteins in the outer segment underlies photoreceptor degeneration in Bardet-Biedl syndrome.

Compartmentalization and polarized protein trafficking are essential for many cellular functions. The photoreceptor outer segment (OS) is a sensory compartment specialized for phototransduction, and it shares many features with primary cilia. As expected, mutations disrupting protein trafficking to cilia often disrupt protein trafficking to the OS and cause photoreceptor degeneration. Bardet-Biedl syndrome (BBS) is one of the ciliopathies associated with defective ciliary trafficking and photoreceptor degeneration. However, precise roles of BBS proteins in photoreceptor cells and the underlying mechanisms of photoreceptor degeneration in BBS are not well understood. Here, we show that accumulation of non-OS proteins in the OS underlies photoreceptor degeneration in BBS. Using a newly developed BBS mouse model [Leucine zipper transcription factor-like 1 (Lztfl1)/Bbs17 mutant], isolated OSs, and quantitative proteomics, we determined 138 proteins that are enriched more than threefold in BBS mutant OS. In contrast, only eight proteins showed a more than threefold reduction. We found striking accumulation of Stx3 and Stxbp1/Munc18-1 and loss of polarized localization of Prom1 within the Lztfl1 and Bbs1 mutant OS. Ultrastructural analysis revealed that large vesicles are formed in the BBS OS, disrupting the lamellar structure of the OS. Our findings suggest that accumulation (and consequent sequestration) of non-OS proteins in the OS is likely the primary cause of photoreceptor degeneration in BBS. Our data also suggest that a major function of BBS proteins in photoreceptors is to transport proteins from the OS to the cell body or to prevent entry of non-OS proteins into the OS.

Medications and "Risk" of Aneurysm Rupture Based on Presentation: Setting the Record Straight.

OBJECTIVE: Studies assessing aneurysm rupture "risk" based on comparative retrospective analyses of medications taken on presentation may be subject to presentation bias. Are patients with ruptured aneurysms simply less likely to be taking medications than those with unruptured aneurysms? METHODS: A retrospective chart review was conducted among patients with treated aneurysms from June 2016 to July 2023. A step-wise comparison of demographics, clinical characteristics (rupture status), and medications taken upon presentation was performed between ruptured and unruptured cases. RESULTS: One thousand three hundred eleven patients with intracranial aneurysms were included. The majority of patients presenting with ruptured aneurysms took no medications (68%), in contrast to 22% with unruptured aneurysms (P < 0.001). The majority of patients with unruptured aneurysms took 2-5 medications (51%), in contrast to 15% of patients with ruptured aneurysms taking 2-5 medications (P < 0.001). Twelve percent of patients with unruptured aneurysms took more than 5 medications, while only 1% with ruptured aneurysms did (P < 0.001). Thirty-five different medications were associated with unruptured presentation, including all evaluated antiplatelet agents, anti-hypertensives, antacids, pulmonary inhalers, and psychiatric medications (P < 0.05); no medications were associated with rupture on presentation. CONCLUSIONS: One cannot derive conclusions about medications and "risk" of rupture based on analyses at the time of presentation. This study identifies 35 different medications that were statistically significant and associated with an unruptured presentation; it is doubtful that each is "protective" against aneurysm rupture.

Intradiscal Osteotomy and Bilateral Expandable Transforaminal Interbody Fusion Cages for Iatrogenic Kyphotic Deformity: A Technical Report.

Objectives Expandable transforaminal interbody fusion (TLIF) devices have been developed to introduce more segmental lordosis through a narrow operative corridor, but there are concerns about the degree of achievable correction with a small graft footprint. In this report, we describe the technical nuances associated with placing bilateral expandable cages for correction of iatrogenic deformity. Materials and Methods A 60-year-old female with symptomatic global sagittal malalignment and a severe lumbar kyphotic deformity after five prior lumbar surgeries presented to our institution. We performed multilevel posterior column osteotomies, a L3-4 intradiscal osteotomy, and placed bilateral lordotic expandable TLIF cages at the level of maximum segmental kyphosis. Results We achieve a 21-degree correction of the patient's focal kyphotic deformity and restoration of the patient global sagittal alignment. Conclusion This case demonstrates both the feasibility and utility of placing bilateral expandable TLIF cages at a single disc space in the setting of severe focal sagittal malalignment. This technique expands the implant footprint and, when coupled with an intradiscal osteotomy, allows for a significant restoration of segmental lordosis.

Pharmaceutical Modulation of Intracranial Aneurysm Development and Rupture.

Management of intracranial aneurysms (IAs) is determined by patient age, risk of rupture, and comorbid conditions. While endovascular and microsurgical interventions offer solutions to mitigate the risk of rupture, pharmacological management strategies may complement these approaches or serve as alternatives in appropriate cases. The pathophysiology of IAs allows for the targeting of inflammation to prevent the development and rupture of IAs. The aim of this review is to provide an updated summary of different pharmaceutical management strategies for IAs. Acetylsalicylic acid and renin-angiotensin-aldosterone system (RAAS) inhibitor antihypertensives have some evidence supporting their protective effect. Studies of selective cyclooxygenase-2 (COX-2) inhibitors, statins, ADP inhibitors, and other metabolism-affecting drugs have demonstrated inconclusive findings regarding their association with aneurysm growth or rupture. In this manuscript, we highlight the evidence supporting each drug's effectiveness.

Machine Learning in Spine Surgery: A Narrative Review.

Artificial intelligence and machine learning (ML) can offer revolutionary advances in their application to the field of spine surgery. Within the past 5 years, novel applications of ML have assisted in surgical decision-making, intraoperative imaging and navigation, and optimization of clinical outcomes. ML has the capacity to address many different clinical needs and improve diagnostic and surgical techniques. This review will discuss current applications of ML in the context of spine surgery by breaking down its implementation preoperatively, intraoperatively, and postoperatively. Ethical considerations to ML and challenges in ML implementation must be addressed to maximally benefit patients, spine surgeons, and the healthcare system. Areas for future research in augmented reality and mixed reality, along with limitations in generalizability and bias, will also be highlighted.

Usefulness and Accuracy of Artificial Intelligence Chatbot Responses to Patient Questions for Neurosurgical Procedures.

BACKGROUND AND OBJECTIVES: The Internet has become a primary source of health information, leading patients to seek answers online before consulting health care providers. This study aims to evaluate the implementation of Chat Generative Pre-Trained Transformer (ChatGPT) in neurosurgery by assessing the accuracy and helpfulness of artificial intelligence (AI)-generated responses to common postsurgical questions. METHODS: A list of 60 commonly asked questions regarding neurosurgical procedures was developed. ChatGPT-3.0, ChatGPT-3.5, and ChatGPT-4.0 responses to these questions were recorded and graded by numerous practitioners for accuracy and helpfulness. The understandability and actionability of the answers were assessed using the Patient Education Materials Assessment Tool. Readability analysis was conducted using established scales. RESULTS: A total of 1080 responses were evaluated, equally divided among ChatGPT-3.0, 3.5, and 4.0, each contributing 360 responses. The mean helpfulness score across the 3 subsections was 3.511 ± 0.647 while the accuracy score was 4.165 ± 0.567. The Patient Education Materials Assessment Tool analysis revealed that the AI-generated responses had higher actionability scores than understandability. This indicates that the answers provided practical guidance and recommendations that patients could apply effectively. On the other hand, the mean Flesch Reading Ease score was 33.5, suggesting that the readability level of the responses was relatively complex. The Raygor Readability Estimate scores ranged within the graduate level, with an average score of the 15th grade. CONCLUSION: The artificial intelligence chatbot's responses, although factually accurate, were not rated highly beneficial, with only marginal differences in perceived helpfulness and accuracy between ChatGPT-3.0 and ChatGPT-3.5 versions. Despite this, the responses from ChatGPT-4.0 showed a notable improvement in understandability, indicating enhanced readability over earlier versions.

Associating T1-Weighted and T2-Weighted Magnetic Resonance Imaging Radiomic Signatures With Preoperative Symptom Severity in Patients With Cervical Spondylotic Myelopathy.

BACKGROUND: Preoperative symptom severity in cervical spondylotic myelopathy (CSM) can be variable. Radiomic signatures could provide an imaging biomarker for symptom severity in CSM. This study utilizes radiomic signatures of T1-weighted and T2-weighted magnetic resonance imaging images to correlate with preoperative symptom severity based on modified Japanese Orthopaedic Association (mJOA) scores for patients with CSM. METHODS: Sixty-two patients with CSM were identified. Preoperative T1-weighted and T2-weighted magnetic resonance imaging images for each patient were segmented from C2-C7. A total of 205 texture features were extracted from each volume of interest. After feature normalization, each second-order feature was further subdivided to yield a total of 400 features from each volume of interest for analysis. Supervised machine learning was used to build radiomic models. RESULTS: The patient cohort had a median mJOA preoperative score of 13; of which, 30 patients had a score of >13 (low severity) and 32 patients had a score of ≤13 (high severity). Radiomic analysis of T2-weighted imaging resulted in 4 radiomic signatures that correlated with preoperative mJOA with a sensitivity, specificity, and accuracy of 78%, 89%, and 83%, respectively (P < 0.004). The area under the curve value for the ROC curves were 0.69, 0.70, and 0.77 for models generated by independent T1 texture features, T1 and T2 texture features in combination, and independent T2 texture features, respectively. CONCLUSIONS: Radiomic models correlate with preoperative mJOA scores using T2 texture features in patients with CSM. This may serve as a surrogate, objective imaging biomarker to measure the preoperative functional status of patients.

Anterior Thoracic Discectomy and Fusion for Symptomatic Ventral Bone Spur Associated Type I Cerebrospinal Fluid Leak: A Technical Report and Operative Video.

STUDY DESIGN: Technical Report. OBJECTIVE: Cerebrospinal fluid (CSF) leak secondary to anterior osteophytes at the cervico-thoracic junction is a rare cause of intracranial hypotension. In this article we describe a technique for anterior repair of spontaneous ventral cerebrospinal fluid leaks in the upper thoracic spine. METHODS: In this technical report and operative video, we describe a 23-year-old male who presented with positional headaches and bilateral subdural hematoma. Dynamic CT myelography demonstrated a high flow ventral cerebrospinal fluid leak associated with a ventral osteophyte at the level of the T1-T2 disc space. Targeted blood patch provided only temporary improvement in symptoms. An anterior approach was chosen to remove the offending spur and micro-surgically repair the dural defect. RESULTS: The patient had complete resolution of his preoperative symptoms after primary repair. CONCLUSIONS: In select cases, an anterior approach to the upper thoracic spine is effective to repair Type 1 cerebrospinal fluid leaks.

Infant Rudimentary Meningocele with Tethering of the Cervical Cord: A Case Report.

Rudimentary meningoceles of the spine with dural extension are very rare and warrant surgical excision to prevent infection and long-term neurological deficits in pediatric patients. We present the case of a 5-month-old infant with a tethered spinal cord secondary to a rudimentary meningocele. The patient presented shortly after birth with a midline cervical dimple that was evaluated for a suspected dermal sinus tract. Magnetic resonance imaging scan of the spine showed a sinus tract with intradural extension to C2-3 and external opening at the level of spinous process C5. En bloc surgical excision and spinal cord release were successfully performed. Histological analysis of the specimen confirmed the presence of two blunt sinus tracts and staining was consistent with a rudimentary meningocele. Intradural rudimentary meningoceles in infants can successfully be managed with surgical intervention. Surgery is indicated to prevent future motor complications from spinal cord tethering and neoplastic growth from the rudimentary meningocele.

Increased prevalence of blister aneurysm formation during the COVID-19 pandemic.

BACKGROUND: Intracranial blister aneurysms are a rare and an historically difficult to treat subset of aneurysms. They are distinct from typical saccular aneurysms with different pathophysiology and treatment options. METHODS: A prospectively maintained database of subarachnoid hemorrhage patients was queried for those presenting prior to the pandemic (2017-2019), and those presenting during the height of the pandemic in our locality (2021). Aneurysm characteristics and patient demographics associated with rupture risk/formation were collected. RESULTS: 334 aneurysmal subarachnoid hemorrhage patients were reviewed. 86 of these patients presented in 2021, with a statistically significant increase in the proportion of ruptured ICA blister aneurysms as compared to 2017-2019 (7/86, 8% vs 5/248, p = .02). Mean patient age, presenting grade, other aneurysm location proportions, aneurysm size, and incidence of delayed cerebral ischemia were not different between the groups. CONCLUSIONS: Patients presenting with SAH during the height of the SARS-CoV-2 pandemic in 2021 were more likely to have ICA blister type aneurysms.

Clopidogrel Is Associated with Reduced Likelihood of Aneurysmal Subarachnoid Hemorrhage: a Multi-Center Matched Retrospective Analysis.

Maladaptive inflammation underlies the formation and rupture of human intracranial aneurysms. There is a growing body of evidence that anti-inflammatory pharmaceuticals may beneficially modulate this process. Clopidogrel (Plavix) is a commonly used irreversible P2Y12 receptor antagonist with anti-inflammatory activity. In this paper, we investigate whether clopidogrel is associated with the likelihood of aneurysm rupture in a multi-institutional propensity-matched cohort analysis. Patients presenting for endovascular treatment of their unruptured intracranial aneurysms and those presenting with aneurysm rupture between 2015 and 2019 were prospectively identified at two quaternary referral centers. Patient demographics, comorbidities, and medication usage at the time of presentation were collected. Patients taking clopidogrel or not taking clopidogrel were matched in a 1:1 fashion with respect to location, age, smoking status, aneurysm size, aspirin usage, and hypertension. A total of 1048 patients with electively treated aneurysms or subarachnoid hemorrhages were prospectively identified. Nine hundred twenty-one patients were confirmed to harbor aneurysms during catheter-based diagnostic angiography. A total of 172/921 (19%) patients were actively taking clopidogrel at the time of presentation. Three hundred thirty-two patients were matched in a 1:1 fashion. A smaller proportion of patients taking clopidogrel at presentation had ruptured aneurysms than those who were not taking clopidogrel (6.6% vs 23.5%, p < .0001). Estimated treatment effect analysis demonstrated that clopidogrel usage decreased aneurysm rupture risk by 15%. We present, to the best of our knowledge, the first large-scale multi-institutional analysis suggesting clopidogrel use is protective against intracranial aneurysm rupture. It is our hope that these data will guide future investigation, revealing the pathophysiologic underpinning of this association.

Power Drill Craniostomy for Bedside Intracranial Access in Traumatic Brain Injury Patients.

Invasive neuromonitoring is a bedrock procedure in neurosurgery and neurocritical care. Intracranial hypertension is a recognized emergency that can potentially lead to herniation, ischemia, and neurological decline. Over 50,000 external ventricular drains (EVDs) are performed in the United States annually for traumatic brain injuries (TBI), tumors, cerebrovascular hemorrhaging, and other causes. The technical challenge of a bedside ventriculostomy and/or parenchymal monitor placement may be increased by complex craniofacial trauma or brain swelling, which will decrease the tolerance of brain parenchyma to applied procedural force during a craniostomy. Herein, we report on the implementation and safety of a disposable power drill for bedside neurosurgical practices compared with the manual twist drill that is the current gold standard. Mechanical testing of the drill's stop extension (n = 8) was conducted through a calibrated tensile tester, simulating an axial plunging of 22.68 kilogram (kg) or 50 pounds of force (lbf) and measuring the strength-responsive displacement. The mean displacement following compression was 0.18 ± 0.11 mm (range of 0.03 mm to 0.34 mm). An overall cost analysis was calculated based on the annual institutional pricing, with an estimated $64.90 per unit increase in the cost of the disposable electric drill. Power drill craniostomies were utilized in a total of 34 adult patients, with a median Glasgow Coma Scale (GCS) score of six. Twenty-seven patients were male, with a mean age of 50.7 years old. The two most common injury mechanisms were falls and motor vehicle/motorcycle accidents. EVDs were placed in all subjects, and additional quad-lumen neuromonitoring was applied to 23 patients, with no incidents of plunging events or malfunctions. One patient developed an intracranial infection and another had intraparenchymal tract hemorrhaging. Two illustrative TBI cases with concomitant craniofacial trauma were provided. The disposable power drill was successfully implemented as an option for bedside ventriculostomies and had an acceptable safety profile.

Patterns in Follow-Up Imaging Usage for Pediatric Patients with Whiplash-Associated Disorder.

BACKGROUND: A clinical concern exists that pediatric patients with whiplash-associated disorder (WAD) might have missed structural injuries or, alternatively, subsequently develop structural injuries over time, despite initially negative imaging findings. The primary objective of this study is to assess follow-up imaging usage for pediatric patients presenting with WAD. METHODS: A retrospective review of 444 pediatric patients presenting to a level 1 pediatric trauma hospital from January 1, 2010 to December 31, 2019 was performed. Imaging was reviewed at the initial encounter and the 3- and 6-month follow-up appointments. RESULTS: At the initial evaluation, children aged <6 years were more likely to receive radiographs (P = 0.007) and magnetic resonance imaging (P = 0.048) than were children aged 6-11 and 12-18 years. At the 3- and 6-month follow-up appointments, persistent neck pain was rare, representing <15% of patients at either time. Regardless of pain persistence, 80.2% of patients seen at the 3-month follow-up and 100% of patients at the 6-month follow-up underwent additional imaging studies. At the 3-month follow-up, children with persistent neck pain were more likely to undergo magnetic resonance imaging than were patients without persistent pain (P < 0.001). Also, patients with persistent neck pain were also more likely to not undergo any imaging evaluation (P = 0.002). Follow-up imaging studies did not reveal new structural injuries at either time point. CONCLUSIONS: Follow-up imaging for pediatric patients with low-grade WAD did not identify new structural pathology-in patients with or without persistent neck pain.

Novel Innovation in Flow Diversion: Surface Modifications.

Flow diversion is a mainstay of modern endovascular aneurysm treatment. Several surface-modified flow diverters have been introduced with a goal to reduce rates of in-stent thrombosis and the need for dual antiplatelet therapy. Preliminary follow-up data suggest that these now commercially available devices are noninferior with respect to rates of angiographic occlusion. These data also suggest that these devices have lower rates of stent-related ischemia. In this chapter, we explore these devices in detail and discuss clinical data regarding their efficacy. We also discuss an alternative bioactive surface modification strategy that has shown in vitro and in vivo efficacy.

T7-T11 Posterior Decompression and Instrumented Fusion, T9 Partial Corpectomy, and Intradural Microsurgical Diskectomy: An Operative Video.

We describe the case of a 57-year-old female with renal cell cancer and metastatic disease to the spine. The patient presented to our institution with progressive lower extremity weakness and a T9 pathologic fracture with bony and tumor retropulsion into the canal. In addition, there was spinal cord compression from a chronic-appearing T8-9 herniated disk fragment. The patient was consented for surgery. In this operative video, we demonstrate the intradural diskectomy following a T7-T11 posterior instrumented fusion, decompression, and transpedicular tumor resection (Video 1). The dorsal and ventral dural closure was reinforced with compressed gelfoam and dural sealant.

Bigger is Still Better: A Step Forward in Reperfusion With React 71.

BACKGROUND: While multiple new larger-bore aspiration catheters have been introduced for stroke thrombectomy, sizeable cohort outcome studies are lacking along with meaningful comparative studies to evaluate whether they represent a clinically relevant improvement compared to predecessors. OBJECTIVE: To evaluate comparative angiographic and clinical outcomes between an 071 and 068 aspiration catheter. METHODS: The authors reviewed an institutional thrombectomy database extracting the first 150 consecutive cases utilizing React 71 (Medtronic, Dublin, Ireland) with a comparison of background/demographic, procedural, angiographic, and clinical outcome variables to a cohort of patients treated with our previously most frequently utilized 0.068-inch aspiration catheter. RESULTS: In our React 71 cohort, successful reperfusion (thrombolysis in cerebral infarction [TICI] 2b-3) was achieved in 95% of cases. In comparison to a prior cohort of 96 patients treated with a 0.068-inch catheter, there was no statistically significant difference in rates of successful reperfusion (TICI 2b-3), initial disposition, and 90-d outcome. However, the frequency of single pass cases was significantly higher in the React 71 cohort (47% vs 35%, P = .019 on multivariate analysis) along with the rate of TICI 2c-3 reperfusion after the first pass (26% vs 14%, P = .019 on multivariate analysis), and final TICI 2c-3 reperfusion (39% vs 28%, P = .04 on multivariate analysis). CONCLUSION: While rates of TICI 2b-3 reperfusion and clinical outcome results were similar, our study suggests that a newer, larger bore aspiration catheter may be associated with a greater frequency of single pass cases and higher quality reperfusion, judged as TICI 2c-3 frequency after the first and final pass.