Clinical Implications of Fat Grafting in the Posterior Calf: A Dynamic Cadaver-based Study.

BACKGROUND: Intramuscular fat grafting in extremity muscles, especially the gastrocnemius, has become increasingly popular. However, while safety in truncal muscle fat grafting has been well-studied, research on extremity muscles is lacking. OBJECTIVES: This study aims to explore the anatomy of the gastrocnemius muscle and adjacent structures concerning intramuscular and subcutaneous recipient sites. Additionally, it seeks to analyze pressure/volume relationships and fat migration patterns during posterior calf grafting. METHODS: Eight cadaveric lower extremities were examined. A prosection was performed to better understand the vascular complex as it exists about the gastrocnemius. Ultrasound-guided fat injections were then performed into both the subcutaneous and intramuscular layers; dynamic pressures were measured with a manometer. Lastly, dyed-injectate was injected subcutaneously to better elucidate subcutaneous anatomy. RESULTS: Anatomic prosection demonstrated the proximity of the gastrocnemius muscle to the popliteal venous system which arborized (>1mm) intramuscularly. In the three specimens that underwent intramuscular fat grafting, the peak intramuscular pressures plateaued at 21mmHg (19.5-23mmHg); there was no observed extra-fascial migration of the injectate. With subcutaneous injectate into one specimen, pressures in the subcutaneous space increased (125mmHg) with additional injectate (240cc) while pressures in the intramuscular space remained relatively constant (4mmHg). CONCLUSIONS: Intramuscular gastrocnemius fat grafting should be done with caution: its proximity to critical veins and sustained increased intramuscular pressures following grafting increases risk of embolus and thrombosis, respectively. Subcutaneous injection may be safer in that increased pressures are not communicated to deep structures. Lastly, we present a novel description of posterior calf subcutaneous compartments that may better allow surgeons to direct and predict subcutaneous injectate.

Tension Reduction With Force Modulating Tissue Bridges Reduces Wounds in Breast Surgery.

BACKGROUND: Tension on healing wounds increases the risk of dehiscence and poor or pathologic scar formation. Force modulating tissue bridges (FMTBs) represent a new class of wound closure and support devices designed to offload tension on healing wounds to improve wound healing and scar outcomes. OBJECTIVES: The study was undertaken to assess the efficacy of FMTBs to reduce the risk of wound healing complications in elective breast surgery. METHODS: One hundred twenty-two consecutive patients undergoing bilateral aesthetic breast surgery underwent intraoperative placement of FMTBs on the vertical limb closure site. A matched case-control cohort of 121 consecutive patients was established for comparison. Wounds were considered significant if larger than 3 mm in diameter. The primary outcome of breast wounds >3 mm was reported with a relative risk, and all outcomes were framed with number needed to treat. RESULTS: The control and intervention cohorts had similar demographics, comorbidities, type of operation, and incision pattern utilized. Within the FMTB group, 96.7% (n = 118) patients completed treatment per protocol. Significant wounds occurred in 1.7% (n = 2) of patients in the tissue bridge vs 15.2% (n = 19) in controls on a per patient/per protocol basis (89% reduction, P < .001). Statistically significant improvements were maintained on sensitivity analyses with intention to treat, even when minor wounds were included. There were no complications noted related to FMTBs. CONCLUSIONS: FMTBs are safe and highly effective at reducing the risk of wound formation in elective breast surgery. Results are consistent with sensitivity analyses based on clinical and methodological factors. Further research will assess long-term scar outcomes.

Deep Subcutaneous Gluteal Fat Compartments: Anatomy and Clinical Implications.

BACKGROUND: Advances in gluteal fat grafting have resulted in diminished risks through improved understanding of regional anatomy and technical nuances. No anatomic studies identifying the presence or absence of buttock fat compartments have yet been reported. OBJECTIVES: The aim of this cadaveric study was to identify and characterize the deep subcutaneous gluteal fat compartments to further understand the nuanced differences between deep and superficial subcutaneous fat layers. METHODS: A cadaveric study was performed to identify the fat compartments. Latex injection into the iliac artery and vein was used to prepare 4 fresh (N = 8 hemibuttocks) hydrated cadavers for dissection. Preliminary work identified the likely position of deep gluteal fat compartments. The cannula was positioned under ultrasound guidance in between the superficial and deep gluteal layers. Cadaveric buttocks were infiltrated by the static technique with dyed human fat, dyed applesauce, and dyed saline in an attempt to identify the gluteal deep subcutaneous fat compartments. RESULTS: Dissection identified and characterized 7 discrete deep gluteal fat compartments. These comprise 3 medial fat compartments (superior, middle, and inferior); a central fat compartment; and 3 lateral (superior, middle, and inferior) deep fat compartments. CONCLUSIONS: Seven deep gluteal fat compartments have been identified that have distinct boundaries and maintain injected contents separate from each other above the gluteal muscle fascia. These compartments can be selectively expanded for buttock augmentation. Knowledge of these compartments enables surgeons to perform gluteal augmentation by static infiltration, injecting autologous fat under ultrasound guidance in the deep subcutaneous fat layer, while optimizing aesthetic considerations.

Depressor Anguli Oris Myectomy versus Transfer to Depressor Labii Inferioris for Facial Symmetry in Synkinetic Facial Paralysis.

BACKGROUND: Postparalytic synkinesis presents with a combination of hypo- and hypertonic muscles, leading to facial asynchrony with animation and at rest. One ubiquitous finding is a hypertonic depressor anguli oris (DAO) muscle and a weak depressor labii inferioris (DLI) muscle. The goal of this study was to evaluate the utility of DAO myectomy with or without its transfer to the weakened DLI in improving critical components of the dynamic smile. METHODS: From 2018 to 2020, this single-center, prospective study included of postparetic facial synkinetic patients with evidence of DAO hypertonicity who underwent DAO myectomy with or without transfer to DLI. Objective facial measurements were used to compare the effectiveness of DAO to DLI transfer to pure DAO myectomy in improving asymmetry of the synkinetic hemiface. RESULTS: Twenty-one patients with unilateral postparetic facial synkinesis with DAO hypertonicity were included; 11 underwent DAO myectomy, while 10 underwent DAO to DLI transfer. Baseline demographics and facial measurements were similar between the groups. DAO myectomy resulted in increased modiolus resting position, closed-mouth smile modiolus angle and excursion, open-mouth smile modiolus angle, excursion, dental show, and decreased lower lip height deviation. DAO to DLI transfer demonstrated similar findings but lacked significant increase in excursion and resulted in worsened lower lip height deviation. CONCLUSION: These findings illustrate the utility of DAO myectomy in improving imbalance in the synkinetic patient and necessitate further technical refinements for DAO transfers or a different approach for improving lower lip depression in this subgroup of patients.

A Comparison of Acellular Dermal Matrices in Abdominal Wall Reconstruction.

BACKGROUND: There is a growing literature of evidence that the use of acellular dermal matrices (ADMs) in abdominal wall reconstruction (AWR) for high-risk patients provides superior complication profiles when compared with standard synthetic mesh. Here we compare Fortiva, Strattice, and Alloderm ADMs in AWR. METHODS: In a prospectively maintained database, all patients undergoing AWR between January 2003 and November 2016 were reviewed. Hernia recurrence and surgical site occurrence (SSO) were our primary and secondary endpoints. Kaplan-Meier survival curves and logistic regression models were used to evaluate risks for hernia recurrence and SSO. RESULTS: A total of 229 patients underwent AWR with 1 of 3 ADMs. Median follow-up time was 20.9 months (1-60 months). Cumulative recurrence rates for each mesh were 6.9%, 11.2%, and 22.0% (P = 0.04), for Fortiva, Strattice, and Alloderm groups. Surgical site occurrence for each mesh was 56.9%, 49.0%, and 49.2%, respectively. Seroma was significantly lower in the Fortiva group (1.4%; P = 0.02). Independent risk factors hernia recurrence included body mass index of 30 kg/m(2) or higher and hypertension. Adjusted risk factors included oncologic resection for hernia recurrence (odds ratio, 5.3; confidence interval, 1.1-97.7; P = 0.11) and a wound class of contaminated or dirty/infected for SSO (odds ratio, 3.6; confidence interval, 1.0-16.6; P = 0.07). CONCLUSIONS: Acellular dermal matrices provide a durable repair with low overall rate of recurrence and complications in AWR. The recurrence and complication profiles differ between brands. With proper patient selection and consideration, ADMs can be used confidently for a variety of indications and wound classifications.

The Hybrid Technique for Autologous Gluteal Augmentation.

This article accompanying these videos will describe the technique created and innovated by the senior author for gluteal augmentation with autologous fat transfer. While the principles of gluteal fat grafting originated with Pitanguy, Regnault, Gonazalez, and Spina, the nuances vary greatly from surgeon to surgeon. Although there is much controversy regarding gluteal fat grafting, the major principle of avoiding intramuscular injection is the central pillar of safe and effective augmentation today. The senior author fine-tuned his method to optimize patient outcomes over the past 14 years and demonstrated lasting, aesthetic results while maximizing patient safety with his technique. More recently, the senior surgeon has developed the Hybrid Technique, involving manual injection of fat through a syringe and a power-assisted cannula to maximize aesthetic outcomes while adhering to safety principles. This method follows the deep and moderate depth subcutaneous injection principle while respecting the muscular, neurovascular, and ligamentous anatomy of the buttock.

Reconstructive Burnout after Mastectomy: Implications for Patient Selection.

BACKGROUND: The reconstructive journey after mastectomy can be a long road, with many hurdles to achieve an ideal aesthetic result. Cancer therapy, operative complications, and comorbidities impact patients physically and emotionally. This study introduces the term reconstructive burnout and aims to evaluate which factors predict and contribute to patients prematurely stopping reconstruction. METHODS: The authors performed a retrospective review of patients undergoing breast reconstruction after skin-sparing mastectomy from 2014 to 2017 performed by two senior surgeons (N.T.H. and S.S.T.) at a single institution. Reconstructive burnout is defined as either no breast mound creation or completion of the breast mound without completion of all major revisions. RESULTS: A total of 530 patients were included, with 76.6% completing reconstruction. In patients undergoing delayed-immediate reconstruction, patients with wounds ( P = 0.004), infections ( P = 0.037), or a complication requiring operative intervention ( P < 0.001) were correlated with incomplete reconstruction; explantation of expanders was highly correlated with reconstructive burnout ( P < 0.001). Implant-based and autologous reconstruction had comparable burnout rates (17.1% versus 19.1%; P = 0.58). Logistic regression models found high body mass index, radiation therapy, any tissue expander complication, and tissue expander explantation to be significant predictors of burnout. Autologous reconstruction was the strongest predictor of completion of reconstruction in both univariable and multivariable models. CONCLUSIONS: Reconstructive burnout in breast reconstruction is associated with tissue expander complications, high body mass indices, and radiation therapy. Overall rates of burnout were comparable between autologous and implant-based reconstruction, with autologous reconstruction being the strongest predictor of completion of reconstruction. It is critical to tailor each patient's reconstructive journey to meet both their emotional and physical needs to avoid reconstructive burnout.

Do Preoperative Depressor Anguli Oris Muscle Blocks Predict Myectomy Outcomes? A Single-Cohort Comparison in Postparetic Facial Synkinesis.

SUMMARY: The complexity of facial synkinesis will likely benefit from an individualized approach to intervene on discrete synkinetic facial subunits. This overarching treatment algorithm requires understanding each synkinetic mimetic subunit. The depressor anguli oris muscle, because of its antagonistic relationship to the zygomaticus major, is of particular interest. This study aims to provide outcomes of depressor anguli oris muscle myectomies and the predictive value of preoperative lidocaine blocks. Preoperative depressor anguli oris muscle lidocaine blocks were administered to patients with postparetic facial synkinesis, and subsequent isolated depressor anguli oris muscle myectomies were performed on those who showed improvement and elected to proceed. Twenty synkinetic patients underwent isolated depressor anguli oris myectomies after lidocaine blockade, with an average follow-up of 9 months. Facial mimetic parameters and measurements were recorded and analyzed by Massachusetts Eye and Ear Infirmary Emotrics and National Institutes of Health ImageJ software to compare results from both blocks and myectomies. Both lidocaine block and depressor anguli oris myectomy improved dental show by 14.42 mm 2 and 23.012 mm 2 , respectively, and open mouth smile angles above a horizontal plane by 4.66 and 3.32 degrees, respectively. There was no statistical difference between the groups in terms of improvements noted in closed and open mouth smile angles above a horizontal plane, or in dental show ( p = 0.695, p = 0.351, and p = 0.242, respectively). Preoperative lidocaine blockade accurately predicts the improvement in dental show and modiolus smile angle that is provided by isolated depressor anguli oris muscle myectomy. This furthers our understanding of depressor anguli oris muscle abnormality in the overall spectrum of facial synkinesis. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Flap Monitoring Using Transcutaneous Oxygen or Carbon Dioxide Measurements.

Free tissue transfer is a cornerstone of complex reconstruction. In many cases, it represents the last option available for a patient and their reconstruction. At high-volume centers, the risk of free flap failure is low but its occurrence can be devastating. Currently, the mainstay for flap monitoring is the clinical examination. Though reliable when performed by experienced clinicians, the flap exam is largely subjective, is performed discontinuously, and often results in significant time delay between detection of flap compromise and intervention. Among emerging flap monitoring technologies, the most promising appear to be those that rely on noninvasive transcutaneous oxygen and carbon dioxide measurements, which provide information regarding flap perfusion. In this article, we review and summarize the literature on various techniques but primarily emphasizing those technologies that rely on transcutaneous gas measurements. We also define characteristics for the ideal flap monitoring tool and discuss critical barriers, predominantly cost, preventing more widespread utilization of adjunct monitoring technologies, and their implications.

Nasal Reconstruction after Mohs Cancer Resection: Lessons Learned from 2553 Consecutive Cases.

BACKGROUND: Nasal defects following Mohs resection are a reconstructive challenge, demanding aesthetic and functional considerations. Many reconstructive modalities are available, each with varying utility and efficacy. The goal of this study was to provide an algorithmic approach to nasal reconstruction and illustrate lessons learned from decades of reconstructing Mohs defects. METHODS: A retrospective review was conducted of consecutive patients who underwent nasal reconstruction after Mohs excision from 2003 to 2019 performed by the senior author (J.F.T.). Data were collected and analyzed regarding patient and clinical demographics, defect characteristics, reconstructive modality used, revisions, and complications. RESULTS: A total of 2553 cases were identified, among which 1550 (1375 patients) were analyzed. Defects most commonly affected the nasal ala (48.1 percent); 74.8 percent were skin-only. Full-thickness skin-grafts were the most common reconstructive method (36.2 percent); 24.4 percent of patients underwent forehead flaps and 17.0 percent underwent nasolabial flaps. The overall complication rate was 11.6 percent (n = 181), with poor wound healing being most common. Age older than 75 years, defects larger than 2 cm2, and active smoking were associated with increased complication rates. CONCLUSIONS: Nasal reconstruction can be divided based on anatomical location, and an algorithmic approach facilitates excellent results. Although local flaps may be suitable for some patients, they are not always the most aesthetic option. The versatility and low risk-to-benefit profile of the forehead flap make it a suitable option for elderly patients. Although reconstruction is still safe to be performed without discontinuation of anticoagulation, older age, smoking, and large defect size are predictors of complications. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Improving plastic surgery resident education and quality of care with outcomes feedback using the surgery report card: An initial experience.

BACKGROUND: The practice of tracking and analyzing surgical outcomes is essential to becoming better surgeons. However, this feedback system is largely absent in residency training programs. Thus, we developed a Surgery Report Card (SRC) for residents performing tissue expander (TE)-based breast reconstruction and report our initial experience with its implementation. METHODS: We performed a systematic review and meta-analysis for TE-based breast reconstructions and compared outcomes to our retrospective cohort. The primary outcome was overall complications. The SRC compares patient and complication statistics for resident-led teams to the meta-analysis. RESULTS: The meta-analysis included 12 studies, with 2093 patients (2982 breasts) that underwent TE-based reconstruction. The pooled complication rate was 26.9%; infection was most common (8.3%); failure rate was 5.9%. Our cohort included 144 patients (245 breasts) among 13 resident-led teams. Overall complication rate was 31.8%; infections were most frequent (17.6%) and failure rate was 7.3%. Our cohort had significantly higher BMIs (29.7 vs 25.4, p<0.0001) more diabetics (6.9% vs. 3.2%, p = 0.02), and more patients receiving adjuvant radiation therapy (41.4 vs 26.3%, p<0.0001). Every 3 months, residents receive a customized SRC of their cases, with the meta-analysis used as a benchmark. A survey demonstrated the SRC made residents reconsider surgical technique and more conscientious surgeons, and would like it implemented for other procedures during residency. CONCLUSIONS: The implementation of our SRC for TE-based breast reconstruction establishes a baseline for surgical performance comparison for residents, demonstrates that residents can safely perform the procedure, and allows for critiquing of surgical techniques to improve patient care.

Achieving balance between resident autonomy and patient safety: Analysis of resident-led microvascular reconstruction outcomes at a microsurgical training center with an established microsurgical training pathway.

BACKGROUND: With advances in microsurgery, the published success rate of microsurgical reconstruction by experienced microsurgeons is greater than 95%. However, it is unknown whether the training residents can produce similar results. At our county hospital, residents perform and lead all aspects of microsurgical reconstruction, from raising the flap to performing microanastomoses. In this study, we retrospectively reviewed the outcomes of 156 consecutive microsurgical cases to determine the efficacy and safety of resident-led reconstructions at the county hospital. METHODS: We performed a retrospective review of patients who underwent microsurgical reconstruction at the county hospital from 2016 to 2018. Demographic, surgical procedure, flap characteristics, resident levels, and complication data were collected. RESULTS: Of the 156 free tissue flaps performed, the most commonly performed reconstruction was for the breast (62.8%), followed by lower extremity (15.9%), upper extremity (10.6%), head and neck (8.8%), and genitalia (1.8%). The average procedure time was 525.1 ±â€¯149.2 min, and mean ischemia time for each flap was 69.8 ±â€¯42.2 min. Venous anastomoses were performed by PGY3 (0.96%), PGY4 (27.9%), PGY5 (18.3%), and PGY6 (47.1%), while the arterial anastomoses were performed by PGY4 (16.4%), PGY5 (11.0%), and PGY6 (69.2%). The average number of anastomosis attempts was 1.3, with a range of 1 to 6. The overall flap success rate was 95.5% with a takeback rate of 7.1%. CONCLUSIONS: In conclusion, our analysis shows that resident-led reconstruction can achieve similar microsurgical success as that of published outcomes. We believe resident-led microsurgical reconstruction can be safely performed, with as-needed faculty assistance in high-risk and complicated cases, while allowing resident education and maturation of technical and decision-making skills.

Reduced Efficacy of the Pipeline Embolization Device in the Treatment of Posterior Communicating Region Aneurysms with Fetal Posterior Cerebral Artery Configuration.

BACKGROUND: Aneurysms at the origin of the posterior communicating artery (PcommA) have been demonstrated to be effectively treated with the pipeline embolization device (PED). Much less is known about the efficacy of the PED for aneurysms associated with a fetal posterior cerebral artery (fPCA) variant. OBJECTIVE: To study PED treatment efficacy of PcommA aneurysms, including fPCA aneurysms. METHODS: A prospectively maintained university database of aneurysm patients treated with the PED was retrospectively reviewed. Demographics, treatment details, and imaging were reviewed for all PcommA and fPCA aneurysms. RESULTS: Out of a total of 285 patients treated with PED, 50 patients (mean age 57.5 ± 12.2 yr, 42 females) with unruptured PcommA (9 fPCA) aneurysms were identified. Mean follow-up duration was 14.0 ± 11.6 mo (48 patients). Roy-Raymond class I occlusion on follow-up magnetic resonance or catheter angiography (mean time 11.7 ± 6.8 mo) was achieved in 30 patients (62.5%), class II occlusion in 11 patients (22.9%) and class III occlusion in 7 patients (14.5%). The PcommA was occluded in 56% of patients without any clinical symptoms. No deaths or permanent neurological complications occurred. In fPCA aneurysms, class I occlusion was seen in 1 patient, class 2 occlusion in 2 patients, and class III occlusion in 6 patients. Multivariate analysis revealed an independent association between incomplete occlusion and fPCA configuration (OR 73.65; 95% CI: 5.84-929.13; P = .001). CONCLUSION: The PED is a safe and effective treatment for PcommA aneurysms, although fetal anatomy should increase consideration of traditional endovascular techniques or surgical clipping.

Multi-faceted computational assessment of risk and progression in oligodendroglioma implicates NOTCH and PI3K pathways.

Oligodendrogliomas are diffusely infiltrative gliomas defined by IDH-mutation and co-deletion of 1p/19q. They have highly variable clinical courses, with survivals ranging from 6 months to over 20 years, but little is known regarding the pathways involved with their progression or optimal markers for stratifying risk. We utilized machine-learning approaches with genomic data from The Cancer Genome Atlas to objectively identify molecular factors associated with clinical outcomes of oligodendroglioma and extended these findings to study signaling pathways implicated in oncogenesis and clinical endpoints associated with glioma progression. Our multi-faceted computational approach uncovered key genetic alterations associated with disease progression and shorter survival in oligodendroglioma and specifically identified Notch pathway inactivation and PI3K pathway activation as the most strongly associated with MRI and pathology findings of advanced disease and poor clinical outcome. Our findings that Notch pathway inactivation and PI3K pathway activation are associated with advanced disease and survival risk will pave the way for clinically relevant markers of disease progression and therapeutic targets to improve clinical outcomes. Furthermore, our approach demonstrates the strength of machine learning and computational methods for identifying genetic events critical to disease progression in the era of big data and precision medicine.

Management of Glioblastoma Multiforme in Elderly Patients: A Review of the Literature.

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults, occurs most commonly in individuals older than 65 years of age, and is universally fatal. Increasing age compounds the poor prognosis of GBM, as elderly patients have markedly worse outcomes than younger patients. However, many of the studies previously investigating optimal treatment regimens exclude patients older than the age of 65 years and thus may not represent the best approaches to ensuring prolonged survival with preserved quality of life. This review aims to highlight the current literature on surgical and medical management, including our own experience, for GBM in the elderly patients, and to provide rational treatment approaches for a vulnerable, often-overlooked, patient population.

Effect of perioperative steroids on dysphagia after anterior cervical spine surgery: A systematic review.

BACKGROUND: Dysphagia following anterior cervical spine surgery is common. Steroids potentially reduce post-operative inflammation that leads to dysphagia; however, the efficacy, optimal dose and route of steroid administration have not been fully elucidated. OBJECTIVE: The purpose of this systematic review is to evaluate the effect of peri-operative steroids on the incidence and severity of dysphagia following anterior cervical spine surgery. METHODS: A PubMed search adherent to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed to include clinical studies reporting use of steroids in adult patients following anterior cervical spine surgery. Data regarding steroid dose, route and timing of administration were abstracted. Incidence and severity of post-operative dysphagia were pooled across studies. RESULTS: Seven of 72 screened articles met inclusion criteria for a total of 246,298 patients that received steroids. Patients that received systemic and local steroids had significant reductions in rate and severity of dysphagia postoperatively. Reduction of dysphagia severity was more pronounced in patients undergoing multilevel procedures in both groups. There was no difference in infectious complications among patients that received steroids compared with controls. There was no difference in fusion rates at long-term follow-up. CONCLUSIONS AND CLINICAL RELEVANCE: Steroids may reduce dysphagia after anterior cervical spinal procedures in the early post-operative period without increasing complications. This may be especially beneficial in patients undergoing multilevel procedures. Future studies should further define the optimal dose and route of steroid administration, and the specific contraindications for use.

Interactive phenotyping of large-scale histology imaging data with HistomicsML.

Whole-slide imaging of histologic sections captures tissue microenvironments and cytologic details in expansive high-resolution images. These images can be mined to extract quantitative features that describe tissues, yielding measurements for hundreds of millions of histologic objects. A central challenge in utilizing this data is enabling investigators to train and evaluate classification rules for identifying objects related to processes like angiogenesis or immune response. In this paper we describe HistomicsML, an interactive machine-learning system for digital pathology imaging datasets. This framework uses active learning to direct user feedback, making classifier training efficient and scalable in datasets containing 108+ histologic objects. We demonstrate how this system can be used to phenotype microvascular structures in gliomas to predict survival, and to explore the molecular pathways associated with these phenotypes. Our approach enables researchers to unlock phenotypic information from digital pathology datasets to investigate prognostic image biomarkers and genotype-phenotype associations.

Effects of Cranioplasty on Cerebral Blood Flow Following Decompressive Craniectomy: A Systematic Review of the Literature.

BACKGROUND: Cranioplasty after decompressive craniectomy (DC) is routinely performed for reconstructive purposes and has been recently linked to improved cerebral blood flow (CBF) and neurological function. OBJECTIVE: To systematically review all available literature to evaluate the effect of cranioplasty on CBF and neurocognitive recovery. METHODS: A PubMed, Google Scholar, and MEDLINE search adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines included studies reporting patients who underwent DC and subsequent cranioplasty in whom cerebral hemodynamics were measured before and after cranioplasty. RESULTS: The search yielded 21 articles with a total of 205 patients (range 3-76 years) who underwent DC and subsequent cranioplasty. Two studies enrolled 29 control subjects for a total of 234 subjects. Studies used different imaging modalities, including CT perfusion (n = 10), Xenon-CT (n = 3), single-photon emission CT (n = 2), transcranial Doppler (n = 6), MR perfusion (n = 1), and positron emission tomography (n = 2). Precranioplasty CBF evaluation ranged from 2 days to 6 months; postcranioplasty CBF evaluation ranged from 7 days to 6 months. All studies demonstrated an increase in CBF ipsilateral to the side of the cranioplasty. Nine of 21 studies also reported an increase in CBF on the contralateral side. Neurological function improved in an overwhelming majority of patients after cranioplasty. CONCLUSION: This systematic review suggests that cranioplasty improves CBF following DC with a concurrent improvement in neurological function. The causative impact of CBF on neurological function, however, requires further study.

Comparison Between CTA and Digital Subtraction Angiography in the Diagnosis of Ruptured Aneurysms.

BACKGROUND: Computerized tomography angiography (CTA) is commonly used to diagnose ruptured cerebral aneurysms with sensitivities reported as high as 97% to 100%. Studies validating CTA accuracy in the setting of subarachnoid hemorrhage (SAH) are scarce and limited by small sample sizes. OBJECTIVE: To evaluate the diagnostic accuracy of CTA in detecting intracranial aneurysms in the setting of SAH. METHODS: A single-center, retrospective cohort of 643 patients was reviewed. A total of 401 patients were identified whose diagnostic workup included both CTA and confirmatory digital subtraction angiography (DSA). Aneurysms missed by CTA but diagnosed by DSA were further stratified by size and location. RESULTS: Three hundred and thirty aneurysms were detected by CTA while DSA detected a total of 431 aneurysms. False positive CTA results were seen for 24 aneurysms. DSA identified 125 aneurysms that were missed by CTA and 83.2% of those were <5 mm in diameter. The sensitivity of CTA was 57.6% for aneurysms smaller than 5 mm in size, and 45% for aneurysms originating from the internal carotid artery. The overall sensitivity of CTA in the setting of SAH was 70.7%. CONCLUSION: The accuracy of CTA in the diagnosis of ruptured intracranial aneurysm may be lower than previously reported. CTA has a low sensitivity for aneurysms less than 5 mm in size, in locations adjacent to bony structures, and for those arising from small caliber parent vessels. It is our recommendation that CTA should be used with caution when used alone in the diagnosis of ruptured intracranial aneurysms.

Predicting clinical outcomes from large scale cancer genomic profiles with deep survival models.

Translating the vast data generated by genomic platforms into accurate predictions of clinical outcomes is a fundamental challenge in genomic medicine. Many prediction methods face limitations in learning from the high-dimensional profiles generated by these platforms, and rely on experts to hand-select a small number of features for training prediction models. In this paper, we demonstrate how deep learning and Bayesian optimization methods that have been remarkably successful in general high-dimensional prediction tasks can be adapted to the problem of predicting cancer outcomes. We perform an extensive comparison of Bayesian optimized deep survival models and other state of the art machine learning methods for survival analysis, and describe a framework for interpreting deep survival models using a risk backpropagation technique. Finally, we illustrate that deep survival models can successfully transfer information across diseases to improve prognostic accuracy. We provide an open-source software implementation of this framework called SurvivalNet that enables automatic training, evaluation and interpretation of deep survival models.