Default mode network electrophysiological dynamics and causal role in creative thinking.

The default mode network (DMN) is a widely distributed, intrinsic brain network thought to play a crucial role in internally-directed cognition. The present study employs stereo-electroencephalography in 13 human patients, obtaining high resolution neural recordings across multiple canonical DMN regions during two processes that have been associated with creative thinking: spontaneous and divergent thought. We probe these two DMN-associated higher cognitive functions through mind wandering and alternate uses tasks, respectively. Our results reveal DMN recruitment during both tasks, as well as a task-specific dissociation in spatiotemporal response dynamics. When compared to the fronto-parietal network, DMN activity was characterized by a stronger increase in gamma band power (30-70 Hz) coupled with lower theta band power (4-8 Hz). The difference in activity between the two networks was especially strong during the mind wandering task. Within the DMN, we found that the tasks showed different dynamics, with the alternate uses task engaging the DMN more during the initial stage of the task, and mind wandering in the later stage. Gamma power changes were mainly driven by lateral DMN sites, while theta power displayed task-specific effects. During alternate uses task, theta changes did not show spatial differences within the DMN, while mind wandering was associated to an early lateral and late dorsomedial DMN engagement. Furthermore, causal manipulations of DMN regions using direct cortical stimulation preferentially decreased the originality of responses in the alternative uses task, without affecting fluency or mind wandering. Our results suggest that DMN activity is flexibly modulated as a function of specific cognitive processes and supports its causal role in divergent thinking. These findings shed light on the neural constructs supporting different forms of cognition and provide causal evidence for the role of DMN in the generation of original connections among concepts.

Intracranial stimulation and EEG feature analysis reveal affective salience network specialization.

Emotion is represented in limbic and prefrontal brain areas, herein termed the affective salience network (ASN). Within the ASN, there are substantial unknowns about how valence and emotional intensity are processed-specifically, which nodes are associated with affective bias (a phenomenon in which participants interpret emotions in a manner consistent with their own mood). A recently developed feature detection approach ('specparam') was used to select dominant spectral features from human intracranial electrophysiological data, revealing affective specialization within specific nodes of the ASN. Spectral analysis of dominant features at the channel level suggests that dorsal anterior cingulate (dACC), anterior insula and ventral-medial prefrontal cortex (vmPFC) are sensitive to valence and intensity, while the amygdala is primarily sensitive to intensity. Akaike information criterion model comparisons corroborated the spectral analysis findings, suggesting all four nodes are more sensitive to intensity compared to valence. The data also revealed that activity in dACC and vmPFC were predictive of the extent of affective bias in the ratings of facial expressions-a proxy measure of instantaneous mood. To examine causality of the dACC in affective experience, 130 Hz continuous stimulation was applied to dACC while patients viewed and rated emotional faces. Faces were rated significantly happier during stimulation, even after accounting for differences in baseline ratings. Together the data suggest a causal role for dACC during the processing of external affective stimuli.

Contralateral C7 nerve transfer for severe pediatric brachial plexus injuries: donor site morbidity.

BACKGROUND: Pediatric brachial plexus injuries (BPI) can have a devastating impact on upper extremity function. With localized lesions, nerve grafting and transfers are well-described. However, reconstruction of pan-plexus (C5-T1) injuries (PPI) requires donor nerves outside of the brachial plexus. The cross C7 (CC7) nerve transfer extended with sural nerve grafts to the contralateral recipient nerve offers the advantage of supplying robust donor axons. Though controversial in the West, CC7 transfer is routine in many Asian centers. We present a case series of pediatric patients who underwent CC7 transfer for BPI. Our objective was to catalog donor site morbidity incurred by transferring the C7 nerve root. METHODS: This retrospective study was approved by the Institutional Review Board of our university. INCLUSION CRITERIA: patients under 18 years old that underwent CC7 nerve transfer for BPI at our health system between 2021 and 2022. A chart review was completed to collect demographic and outcomes data. RESULTS: Three patients underwent a complete CC7 transfer between 2021 and 2022 for BPI reconstruction. All patients underwent concomitant additional nerve transfers. Post-operative donor site sensory deficits were minimal and transient in all but one patient, who reported mild but persistent paresthesia of the donor side hand with movement of recipient side digits; however, no patients suffered donor site motor deficits (Table 1). CONCLUSIONS: We conclude that CC7 nerve transfer is a safe surgical option to provide additional donor motor axons for PPI in pediatric patients.

Long-Term Outcomes After Treatment for Type B Ulnar Polydactyly.

BACKGROUND: Type B ulnar polydactyly is a common congenital hand difference and can be treated with either ligation or surgical excision. There is a paucity of literature, however, evaluating long-term patient reported outcomes of these treatments. The purpose of this study was to compare the long-term outcomes after ligation and excision for the management of type B ulnar polydactyly. METHODS: We created a database of patients who underwent treatment for type B ulnar polydactyly at a single pediatric health system from 2005 to 2014. We administered the Patient Reported Outcomes Measurement Information System (PROMIS) Pediatric Upper Extremity survey to patients through telephone and assessed for their satisfaction. RESULTS: We successfully collected outcomes from 69 of 173 eligible patients treated in infancy (40% response rate). The mean follow-up was 11.1±2.5 years, and the average age of the participant at the time of the survey was 11.7±2.6 years of age. Twenty-four patients were treated with in-office ligation and 45 underwent formal surgical excision. Ten patients who were initially treated with ligation required future treatment with surgery because of symptomatic neuroma stump or persistent polydactyly (42%). Patients who were treated with surgical excision rated significantly higher satisfaction with their treatment than those who underwent ligation (P=0.003). Patients in both cohorts rated similar satisfaction with the esthetic appearance of their hand (P=0.07). There was no significant difference in PROMIS-rated hand function between the ligation and surgical cohort (P=0.765) and treated adolescents PROMIS scores were not statistically different than age-matched controls without polydactyly. CONCLUSION: While ligation and surgical excision result in similar function and esthetics, patient satisfaction is higher after surgery. Furthermore, a significant number of patients fail ligation and ultimately undergo surgery for symptomatic neuroma or persistent polydactyly. Counseling parents of patients with type B ulnar polydactyly should include these considerations to assist them in selecting the best treatment for their child. LEVEL OF EVIDENCE: Level III.

Multivariate Matching Pursuit Decomposition and Normalized Gabor Entropy for Quantification of Preictal Trends in Epilepsy.

Quantification of the complexity of signals recorded concurrently from multivariate systems, such as the brain, plays an important role in the study and characterization of their state and state transitions. Multivariate analysis of the electroencephalographic signals (EEG) over time is conceptually most promising in unveiling the global dynamics of dynamical brain disorders such as epilepsy. We employed a novel methodology to study the global complexity of the epileptic brain en route to seizures. The developed measures of complexity were based on Multivariate Matching Pursuit (MMP) decomposition of signals in terms of time-frequency Gabor functions (atoms) and Shannon entropy. The measures were first validated on simulation data (Lorenz system) and then applied to EEGs from preictal (before seizure onsets) periods, recorded by intracranial electrodes from eight patients with temporal lobe epilepsy and a total of 42 seizures, in search of global trends of complexity before seizures onset. Out of five Gabor measures of complexity we tested, we found that our newly defined measure, the normalized Gabor entropy (NGE), was able to detect statistically significant (p < 0.05) nonlinear trends of the mean global complexity across all patients over 1 h periods prior to seizures' onset. These trends pointed to a slow decrease of the epileptic brain's global complexity over time accompanied by an increase of the variance of complexity closer to seizure onsets. These results show that the global complexity of the epileptic brain decreases at least 1 h prior to seizures and imply that the employed methodology and measures could be useful in identifying different brain states, monitoring of seizure susceptibility over time, and potentially in seizure prediction.

A Systematic Review and Comparison of Outcomes Following Simple Syndactyly Reconstruction With Skin Grafts or a Dorsal Metacarpal Advancement Flap.

PURPOSE: Many techniques exist for simple syndactyly reconstruction. The most commonly used techniques involve either skin grafts or a dorsal metacarpal advancement flap. Our aim was to review and compare the outcomes of these 2 techniques systematically. METHODS: We reviewed articles from PubMed, MEDLINE, EMBASE, and Google Scholar published between January 1966 and January 2016. We identified studies that reported outcomes after reconstruction of simple syndactyly using skin grafts and those using only a dorsal metacarpal advancement flap. Cases of complex syndactyly and those that were not clearly differentiated by technique or type of simple syndactyly were excluded. Outcomes were then stratified by technique and type of syndactyly (complete and incomplete). RESULTS: We identified 693 articles and selected 34 for inclusion. No standardized outcome measure was uniformly applied in the examined studies. Overall, skin grafting procedures were associated with more complications (eg, flap necrosis/graft failure, contracture, web creep, hypertrophic scarring) and a greater need for revision. When stratified by subtype, patients with simple, complete syndactyly who underwent skin grafting had a significantly higher rate of hypertrophic scarring than those who underwent reconstruction with a dorsal metacarpal advancement flap. CONCLUSIONS: Simple syndactyly reconstruction with a dorsal metacarpal advancement flap may lead to fewer complications than procedures using skin grafts. However, substantial limitations of currently available evidence do not allow for the recommendation of a specific technique. Future research should use a uniform reporting system for syndactyly classification and complications. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Anesthetic Neurotoxicity in Congenital Hand Surgery: An Overview of the Evidence and Advice for Counseling Parents.

Millions of children undergo general anesthesia for surgical procedures each year, the implications of which are not fully understood. Animal models demonstrate neurotoxicity and long-term cognitive impairment following exposure to common general anesthetic agents. However, it is unclear if human brains are affected in a similar fashion and what-if any-the implications on cognitive development may be. Furthermore, it is not known if these effects are additive and if they can be avoided by delaying reconstruction. Here, we explore reconstructive surgical timelines for common congenital hand differences in light of the available anesthetic neurotoxicity evidence, with an emphasis on preoperative counseling.

Congenital Hand Differences.

Congenital hand differences are frequently encountered by pediatric plastic surgeons. These anomalies may cause significant emotional and functional challenges for children. Pediatric plastic surgery nurses should have a basic understanding of common congenital hand differences and related treatment options to facilitate patient education and postoperative care. This article discusses clinical findings and management of 4 of the most common hand anomalies: syndactyly, polydactyly, thumb hypoplasia, and cleft hand. The goals of surgical treatment are to maximize hand function and aesthetics with minimal adverse outcomes.

Pediatric Hand Injuries.

Pediatric hand injuries are extremely common. Although many hand injuries are adequately managed in the emergency department, some may need evaluation and treatment by a pediatric hand surgeon to ensure a good functional outcome. This article discusses the diagnosis and management of the most common pediatric hand maladies: fingertip injuries/amputation, tendon injuries, and phalangeal and metacarpal fractures. The plastic surgery nurse should be familiar with hand injuries that require intervention to facilitate efficient management and optimal postoperative care.

Do Patient- and Parent-reported Outcomes Measures for Children With Congenital Hand Differences Capture WHO-ICF Domains?

BACKGROUND: Patient- and parent-reported outcome measures (PROMs) are increasingly used to evaluate the effectiveness of surgery for congenital hand differences (CHDs). Knowledge of an existing outcome measure's ability to assess self-reported health, including psychosocial aspects, can inform the future development and application of PROMs for CHD. However, the extent to which measures used among children with CHD align with common, accepted metrics of self-reported disability remains unexplored. QUESTIONS/PURPOSES: We reviewed studies that used PROMs to evaluate surgery for CHD to determine (1) the number of World Health Organization-International Classification of Functioning, Disability and Health (WHO-ICF) domains covered by existing PROMs; (2) the proportion of studies that used PROMs specifically validated among children with CHD; and (3) the proportion of PROMs that targets patients and/or parents. METHODS: We performed a comprehensive review of the literature through a bibliographic search of MEDLINE®, PubMed, and EMBASE from January 1966 to December 2014 to identify articles related to patient outcomes and surgery for CHD. We evaluated the 42 studies that used PROMs to identify the number and type of WHO-ICF domains captured by existing PROMs for CHD and the proportion of studies that use PROMs validated for use among children with CHD. The most common instruments used to measure patient- and parent-reported outcomes after reconstruction for CHD included the Prosthetic Upper Extremity Functional Index (PUFI), Disabilities of the Arm, Shoulder, and Hand questionnaire, Childhood Experience Questionnaire, and Pediatric Quality of Life Inventory. RESULTS: Current PROMs that have been used for CHD covered a mean of 1.3 WHO-ICF domains (SD ± 1.3). Only the Child Behavior Checklist and the Piers-Harris Children's Self-Concept Scale captured all ICF domains (body functions and structures, activity, participation, and environmental factors). The PUFI, the only PROM validated specifically for children with congenital longitudinal and transverse deficiency, was used in only four of 42 studies. Only 13 of the 42 studies assessed patient-reported outcomes, whereas five assessed both patient- and parent-reported outcomes. CONCLUSIONS: The PROMs used to assess patients after CHD surgery do not evaluate all WHO-ICF domains (ie, body structure, body function, environmental factors, and activity and participation) and generally are not validated for children with CHD. Given the psychological and sociological aspects of CHD illness, a PROM that encompasses all components of the biopsychosocial model of illness and validated in children with CHD is desirable. LEVEL OF EVIDENCE: Level III, therapeutic study.

Tissue Expander Complications Predict Permanent Implant Complications and Failure of Breast Reconstruction.

BACKGROUND: Two-stage tissue expander-based breast reconstruction is the most commonly used reconstructive modality following mastectomy. We sought to determine if patients who experienced complications during the expansion phase were at increased risk for complications or reconstructive failure after the exchange procedure. METHODS: A retrospective review of tissue expander-based breast reconstructions was performed from January 2007 through December 2011. Variables evaluated included age, presence of cancer, tobacco use, body mass index, comorbidities, use of acellular dermal matrix, chemotherapy, radiation, timing of reconstruction (delayed/immediate), intraoperative tissue expander fill, complications, and explantation or salvage of the reconstruction by means of debridement and closure or myocutaneous flap. RESULTS: A total of 196 patients underwent mastectomy with 304 tissue expander reconstructions. Tobacco use (active and remote), hypertension, and radiation were associated with complications. Patients with a salvaged tissue expander complication were 3 times more likely to have a complication after placement of a permanent implant and 9 times more likely to fail permanent implant reconstruction (ie, require explantation). CONCLUSIONS: Women with complications after placement of a tissue expander are at significantly increased risk for both complications and reconstructive failure after placement of a permanent implant. Consideration for earlier autologous reconstruction as a salvage should be strongly considered in patients with a tissue expander complication, particularly in smokers and those undergoing radiation therapy.

Lifelong Learning for the Hand Surgeon.

Hand surgeons are faced with the impossible task of mastering a rapidly expanding pool of knowledge and surgical techniques. Dedication to lifelong learning is, therefore, an essential component of delivering the best, most up-to-date care for patients. Board certification, participation in continuing medical education and maintenance of certification activities, and attendance at national meetings are essential mechanisms by which hand surgeons may foster the acquisition of essential knowledge and clinical skills, This article highlights the history, current status, and emerging needs in continuing medical education for the hand surgeon.

Surgical Treatment of Cubital Tunnel Syndrome: Trends and the Influence of Patient and Surgeon Characteristics.

PURPOSE: To examine trends in and determinants of the use of different procedures for treatment of cubital tunnel syndrome. METHODS: We performed a retrospective cross-sectional analysis of the Healthcare Cost and Utilization Project Florida State Ambulatory Surgery Database for 2005 to 2012. We selected all patients who underwent in situ decompression, transposition, or other surgical treatments for cubital tunnel syndrome. We tested trends in the use of these techniques and performed a multivariable analysis to examine associations among patient characteristics, surgeon case volume, and the use of different techniques. RESULTS: Of the 26,164 patients who underwent surgery for cubital tunnel syndrome, 80% underwent in situ decompression, 16% underwent transposition, and 4% underwent other surgical treatment. Over the study period, there was a statistically significant increase in the use of in situ release and a decrease in the use of transposition. Women and patients treated by surgeons with a higher cubital tunnel surgery case volume underwent in situ release with a statistically higher incidence than other techniques. CONCLUSIONS: In Florida, surgeon practice reflected the widespread adoption of in situ release as the primary treatment for cubital tunnel syndrome, and its relative incidence increased during the study period. Patient demographics and surgeon-level factors influenced procedure selection. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic III.

Impact of Injury Mechanisms on Patterns and Management of Facial Fractures.

Mechanisms causing facial fractures have evolved over time and may be predictive of the types of injuries sustained. The objective of this study is to examine the impact of mechanisms of injury on the type and management of facial fractures at our Level 1 Trauma Center. The authors performed an Institutional Review Board-approved review of our network's trauma registry from 2006 to 2010, documenting age, sex, mechanism, Injury Severity Score, Glasgow Coma Scale, facial fracture patterns (nasal, maxillary/malar, orbital, mandible), and reconstructions. Mechanism rates were compared using a Pearson χ2 test. The database identified 23,318 patients, including 1686 patients with facial fractures and a subset of 1505 patients sustaining 2094 fractures by motor vehicle collision (MVC), fall, or assault. Nasal fractures were the most common injuries sustained by all mechanisms. MVCs were most likely to cause nasal and malar/maxillary fractures (P < 0.01). Falls were the least likely and assaults the most likely to cause mandible fractures (P < 0.001), the most common injury leading to surgical intervention (P < 0.001). Although not statistically significant, fractures sustained in MVCs were the most likely overall to undergo surgical intervention. Age, number of fractures, and alcohol level were statistically significant variables associated with operative management. Age and number of fractures sustained were associated with operative intervention. Although there is a statistically significant correlation between mechanism of injury and type of facial fracture sustained, none of the mechanisms evaluated herein are statistically associated with surgical intervention. Clinical Question/Level of Evidence: Therapeutic, III.

Addressing medical errors in hand surgery.

Influential think tanks such as the Institute of Medicine have raised awareness about the implications of medical errors. In response, organizations, medical societies, and hospitals have initiated programs to decrease the incidence and prevent adverse effects of these errors. Surgeons deal with the direct implications of adverse events involving patients. In addition to managing the physical consequences, they are confronted with ethical and social issues when caring for a harmed patient. Although there is considerable effort to implement system-wide changes, there is little guidance for hand surgeons on how to address medical errors. Admitting an error by a physician is difficult, but a transparent environment where patients are notified of errors and offered consolation and compensation is essential to maintain physician-patient trust. Furthermore, equipping hand surgeons with a guide for addressing medical errors will help identify system failures, provide learning points for safety improvement, decrease litigation against physicians, and demonstrate a commitment to ethical and compassionate medical care.

The clinical implications of the oblique retinacular ligament.

The oblique retinacular ligament originates from the flexor tendon sheath, courses past the proximal interphalangeal joint, and merges with the lateral extensor tendon. There has been disagreement regarding the contribution of the oblique retinacular ligament to coordinated movements between the proximal and distal interphalangeal joints. Landsmeer postulated that it acts as a dynamic tenodesis that tightens with proximal interphalangeal joint extension, causing obligatory distal interphalangeal joint extension. However, studies have shown that the oblique retinacular ligament is variably present and often attenuated, which diminishes its presumed role in finger movement. Despite this, the concept of a checkrein linking interphalangeal joint motion heralded the development of effective and reproducible surgical interventions for swan-neck and mallet deformities. This article examines the controversy regarding the existence of the oblique retinacular ligament, its plausible functionality, and clinical implications in the practice of hand surgery.

A biophysically constrained brain connectivity model based on stimulation-evoked potentials.

BACKGROUND: Single-pulse electrical stimulation (SPES) is an established technique used to map functional effective connectivity networks in treatment-refractory epilepsy patients undergoing intracranial-electroencephalography monitoring. While the connectivity path between stimulation and recording sites has been explored through the integration of structural connectivity, there are substantial gaps, such that new modeling approaches may advance our understanding of connectivity derived from SPES studies. NEW METHOD: Using intracranial electrophysiology data recorded from a single patient undergoing stereo-electroencephalography (sEEG) evaluation, we employ an automated detection method to identify early response components, C1, from pulse-evoked potentials (PEPs) induced by SPES. C1 components were utilized for a novel topology optimization method, modeling 3D electrical conductivity to infer neural pathways from stimulation sites. Additionally, PEP features were compared with tractography metrics, and model results were analyzed with respect to anatomical features. RESULTS: The proposed optimization model resolved conductivity paths with low error. Specific electrode contacts displaying high error correlated with anatomical complexities. The C1 component strongly correlated with additional PEP features and displayed stable, weak correlations with tractography measures. COMPARISON WITH EXISTING METHOD: Existing methods for estimating neural signal pathways are imaging-based and thus rely on anatomical inferences. CONCLUSIONS: These results demonstrate that informing topology optimization methods with human intracranial SPES data is a feasible method for generating 3D conductivity maps linking electrical pathways with functional neural ensembles. PEP-estimated effective connectivity is correlated with but distinguished from structural connectivity. Modeled conductivity resolves connectivity pathways in the absence of anatomical priors.

Active nerve management for above the knee amputation: A comparison of through the wound versus posterior approach.

Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) are used to prevent or treat neuromas in amputees. TMR for above-the-knee amputation (AKA) is most commonly performed through a posterior incision rather than the stump wound because recipient motor nerves are primarily located in the proximal third of the thigh. When preventative TMR is performed with concurrent AKA, a posterior approach requires intraoperative repositioning and an additional incision. The purpose of this study was to evaluate feasibility of TMR and operative times for nerve management performed through the wound compared to a posterior approach in AKA patients to guide surgical decision-making. Patients who underwent AKA with TMR between 2018-2023 were reviewed. Patients were divided into two groups: TMR performed through the wound (Group I) and TMR performed through a posterior approach (Group II). If a nerve was unable to undergo coaptation for TMR due to the lack of suitable donor motor nerves, RPNI was performed. Eighteen patients underwent AKA with nerve management were included from Group I (8 patients) and Group II (10 patients). TMR coaptations performed on distinct nerves was 1.5 ± 0.5 in Group I compared to 2.6 ± 0.5 in Group II (p = 0.001). Operative time for Group I was 200.7 ± 33.4 min compared to 326.5 ± 37.1 min in Group II (p = 0.001). TMR performed through the wound following AKA requires less operative time than a posterior approach. However, since recipient motor nerves are not consistently found near the stump, RPNI may be required with TMR whereas the posterior approach allows for more TMR coaptations.

Beta activity in human anterior cingulate cortex mediates reward biases.

The rewards that we get from our choices and actions can have a major influence on our future behavior. Understanding how reward biasing of behavior is implemented in the brain is important for many reasons, including the fact that diminution in reward biasing is a hallmark of clinical depression. We hypothesized that reward biasing is mediated by the anterior cingulate cortex (ACC), a cortical hub region associated with the integration of reward and executive control and with the etiology of depression. To test this hypothesis, we recorded neural activity during a biased judgment task in patients undergoing intracranial monitoring for either epilepsy or major depressive disorder. We found that beta (12-30 Hz) oscillations in the ACC predicted both associated reward and the size of the choice bias, and also tracked reward receipt, thereby predicting bias on future trials. We found reduced magnitude of bias in depressed patients, in whom the beta-specific effects were correspondingly reduced. Our findings suggest that ACC beta oscillations may orchestrate the learning of reward information to guide adaptive choice, and, more broadly, suggest a potential biomarker for anhedonia and point to future development of interventions to enhance reward impact for therapeutic benefit.

Insula uses overlapping codes for emotion in self and others.

In daily life, we must recognize others' emotions so we can respond appropriately. This ability may rely, at least in part, on neural responses similar to those associated with our own emotions. We hypothesized that the insula, a cortical region near the junction of the temporal, parietal, and frontal lobes, may play a key role in this process. We recorded local field potential (LFP) activity in human neurosurgical patients performing two tasks, one focused on identifying their own emotional response and one on identifying facial emotional responses in others. We found matching patterns of gamma- and high-gamma band activity for the two tasks in the insula. Three other regions (MTL, ACC, and OFC) clearly encoded both self- and other-emotions, but used orthogonal activity patterns to do so. These results support the hypothesis that the insula plays a particularly important role in mediating between experienced vs. observed emotions.