Search

Sensorimotor integration can be assessed by pairing electrical peripheral nerve stimulation with transcranial magnetic stimulation (TMS). The resulting afferent inhibition is observed when TMS precedes nerve stimulation by ∼ 20-25 ms, termed short-latency afferent inhibition (SAI), or by 200 ms, termed long-latency afferent inhibition (LAI). The purpose of this study was to determine whether biological sex influences the magnitude of SAI or LAI. SAI and LAI were assessed in fifteen males (21.5 ± 2.7 years) and fifteen females (20.2 ± 2.3 years). TMS was delivered to the primary motor cortex (M1) following stimulation of the contralateral median nerve at the wrist or digital nerve of the index finger, and motor-evoked potentials (MEPs) were obtained from the right first dorsal interosseous (FDI) muscle. SAI evoked by median and digital nerve stimulation, and LAI evoked by median nerve stimulation, were not different between males and females. LAI evoked by digital nerve stimulation was increased in females compared to males, but this difference between sexes was no longer present following the removal of datapoints where inhibition was not observed. This study is the first to investigate biological sex differences in afferent inhibition., (Copyright © 2021. Published by Elsevier B.V.)

Objective: It is unclear why specific individuals incur chronic symptoms following a concussion. This exploratory research aims to identify and characterize any neurophysiological differences that may exist in motor cortex function in post-concussion syndrome (PCS)., Methods: Fifteen adults with PCS and 13 healthy, non-injured adults were tested. All participants completed symptom questionnaires, and transcranial magnetic stimulation (TMS) was used to measure intracortical and transcallosal excitability and inhibition in the dominant motor cortex., Results: Cortical silent period (p = 0.02, g = 0.96) and ipsilateral silent period (p = 0.04, g = 0.78) were shorter in the PCS group compared to the control group which may reflect reduced GABA-mediated inhibition in PCS. Furthermore, increased corticomotor excitability was observed in the left hemisphere but not the right hemisphere., Conclusions: These data suggest that persistent neurophysiological differences are present in those with PCS. The exact contributing factors to such changes remain to be investigated by future studies., Significance: This study provides novel evidence of lasting neurophysiological changes in PCS., (© 2020 International Federation of Clinical Neurophysiology. Published by Elsevier B.V.)

Previous research has demonstrated a lack of neuroplasticity induced by acute exercise in low fit individuals, but the influence of exercise intensity is unclear. In the present study, we assessed the effect of acute high-intensity (HI) or moderate-intensity (MOD) interval exercise on neuroplasticity in individuals with low fitness, as determined by a peak oxygen uptake (VO2peak) test (n = 19). Transcranial magnetic stimulation (TMS) was used to assess corticospinal excitability via area under the motor evoked potential (MEP) recruitment curve before and following training. Corticospinal excitability was unchanged after HI and MOD, suggesting no effect of acute exercise on neuroplasticity as measured via TMS in sedentary, young individuals. Repeated bouts of exercise, i.e., physical training, may be required to induce short-term changes in corticospinal excitability in previously sedentary individuals., Competing Interests: The authors have declared that no competing interests exist.

Neurotransmission is highly dependent on the availability of glucose-derived energy, although it is unclear how glucose availability modulates corticospinal and intracortical excitability as assessed via transcranial magnetic stimulation (TMS). In this double-blinded placebo-controlled study, we tested the effect of acute glucose intake on motor-evoked potential (MEP) recruitment curves, short-interval intracortical inhibition (SICI), short-latency afferent inhibition (SAI) and long-latency afferent inhibition (LAI). Eighteen healthy males participated in four sessions. Session 1 involved acquisition of an individualized blood glucose response curve. This allowed measurements to be time-locked to an individualized glucose peak after consuming one of three drinks during the subsequent three sessions. Participants were administered a 300 mL concealed solution containing 75 g of glucose, sucralose, or water in separate sessions. Dependent measures were assessed at baseline and twice after drinking the solution. Secondary measures included blood glucose and mean arterial pressure. Corticospinal excitability and blood pressure increased following the drink across all treatments. No changes were observed in SICI, SAI or LAI. There was no rise in corticospinal excitability that was specific to the glucose drink, suggesting that acute changes in glucose levels do not necessarily alter TMS measures of corticospinal or intracortical excitability., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Interhemispheric inhibition (IHI) between motor cortexes is thought to suppress unwanted mirror movements during voluntary behaviors and can be assessed using paired-pulse transcranial magnetic stimulation (TMS). The magnitude of IHI may be related to the size of the cortical representation for a given muscle as a mechanism for facilitating unimanual control. To date, the relationship between IHI and cortical muscle representations remains unknown. Fifteen healthy, right-handed individuals participated in the present study. IHI was examined in the right first dorsal interosseous (FDI) muscle by delivering conditioning TMS to ipsilateral (right) primary motor cortex (M1) followed by a test TMS pulse to contralateral (left) M1. The size of the FDI representation in M1 was determined by delivering suprathreshold TMS over a 5 × 5-cm grid centered on the FDI motor hotspot of the left M1. Both IHI and cortical territory were obtained during three conditions: rest, contralateral (right) FDI contraction, and ipsilateral (left) FDI contraction. Results indicate a significant association between IHI and the size of the FDI representation only in the context of contraction and not when the FDI muscle was relaxed. Specifically, reduced IHI corresponded to larger cortical FDI representations during both contralateral and ipsilateral contraction. These data demonstrate that, for a muscle of the hand, the magnitude of IHI and the cortical territory are associated within the context of muscle contraction. NEW & NOTEWORTHY This study provides evidence from noninvasive brain stimulation that communication between the motor cortexes of the two hemispheres plays a role in shaping the motor cortical map that outputs to a hand muscle during active contraction of that muscle. This relationship exists only when the hand muscle is contracted. The findings presented further our understanding of motor control during unilateral movement and may inform future research targeting clinical populations that exhibit impaired unilateral control.

Aerobic exercise improves cognitive and motor function by inducing neural changes detected using molecular, cellular, and systems level neuroscience techniques. This review unifies the knowledge gained across various neuroscience techniques to provide a comprehensive profile of the neural mechanisms that mediate exercise-induced neuroplasticity. Using a model of exercise-induced neuroplasticity, this review emphasizes the sequence of neural events that accompany exercise, and ultimately promote changes in human performance. This is achieved by differentiating between neuroplasticity induced by acute versus chronic aerobic exercise. Furthermore, this review emphasizes experimental considerations that influence the opportunity to observe exercise-induced neuroplasticity in humans. These include modifiable factors associated with the exercise intervention and nonmodifiable factors such as biological sex, ovarian hormones, genetic variations, and fitness level. To maximize the beneficial effects of exercise in health, disease, and following injury, future research should continue to explore the mechanisms that mediate exercise-induced neuroplasticity. This review identifies some fundamental gaps in knowledge that may serve to guide future research in this area.

Key Points: Short-latency afferent inhibition (SAI) is modulated by GABA A receptor activity, whereas the pharmacological origin of long-latency afferent inhibition remains unknown. This is the first study to report that long-latency afferent inhibition (LAI) is reduced by the GABA A positive allosteric modulator lorazepam, and that both SAI and LAI are not modulated by the GABA B agonist baclofen. These findings advance our understanding of the neural mechanisms underlying afferent inhibition., Abstract: The afferent volley evoked by peripheral nerve stimulation has an inhibitory influence on transcranial magnetic stimulation induced motor evoked potentials. This phenomenon, known as afferent inhibition, occurs in two phases: short-latency afferent inhibition (SAI) and long-latency afferent inhibition (LAI). SAI exerts its inhibitory influence via cholinergic and GABAergic activity. The neurotransmitter receptors that mediate LAI remain unclear. The present study aimed to determine whether LAI is contributed by GABA A and/or GABA B receptor activity. In a double-blinded, placebo-controlled study, 2.5 mg of lorazepam (GABA A agonist), 20 mg of baclofen (GABA B agonist) and placebo were administered to 14 males (mean age 22.7 ± 1.9 years) in three separate sessions. SAI and LAI, evoked by stimulation of the median nerve and recorded from the first dorsal interosseous muscle, were quantified before and at the peak plasma concentration following drug ingestion. Results indicate that lorazepam reduced LAI by ∼40% and, in support of previous work, reduced SAI by ∼19%. However, neither SAI, nor LAI were altered by baclofen. In a follow-up double-blinded, placebo-controlled study, 10 returning participants received placebo or 40 mg of baclofen (double the dosage used in Experiment 1). The results obtained indicate that SAI and LAI were unchanged by baclofen. This is the first study to show that LAI is modulated by GABA A receptor activity, similar to SAI, and that afferent inhibition does not appear to be a GABA B mediated process., (© 2018 The Authors. The Journal of Physiology © 2018 The Physiological Society.)

Background: Many plastic surgery departments in Australasia have experienced increasing referrals for management of skin lesions. This has driven a demand for new strategies to decrease patient waiting time and administrative costs. The aim of this study was to determine if a purpose-built See and Treat skin cancer clinic could provide a faster skin cancer treatment pathway with comparable clinical outcomes and acceptability to patients., Methods: This was a prospective observational study of patients treated through the See and Treat clinic with a retrospective control cohort. The prospective 'See and Treat' cohort included a consecutive series of 106 patients, while the retrospective cohort included a consecutive series of 200 patients. Patient demographics, time from referral to surgery and operative measures were analysed. One hundred patients in the prospective cohort completed an anonymous satisfaction survey regarding their treatment., Results: The average time from referral to surgery was reduced from 121 days in the retrospective cohort to 60 days in the See and Treat cohort (P < 0.001). Rates of complete excision of malignant and premalignant lesions were not different between the two groups, being 93% (178/191) and 91% (76/84), respectively (P = 0.609). Ninety-five percent (95/100) of patients were satisfied with their See and Treat experience overall., Conclusion: We show that a considerable reduction in the time between referral and surgery can be achieved through a See and Treat clinic without compromise of the success of surgical treatment. Moreover, such a treatment pathway has been shown to be acceptable, and largely preferable, to patients., (© 2017 Royal Australasian College of Surgeons.)

(1) Background: Afferent inhibition is the attenuation of the muscle response evoked from transcranial magnetic stimulation (TMS) by a prior conditioning electrical stimulus to a peripheral nerve. It is unclear whether the magnitude of afferent inhibition relates to sensation and movement; (2) Methods: 24 healthy, young adults were tested. Short-latency afferent inhibition (SAI) and long-latency afferent inhibition (LAI) were obtained following median and digital nerve stimulation. Temporal tactile acuity was assessed with a temporal order judgement (TOJ) task, spatial tactile acuity was assessed using a grating orientation task (GOT), and fine manual dexterity was assessed with the Pegboard task; (3) Results: Correlation analyses revealed no association between the magnitude of SAI or LAI with performance on the TOJ, GOT, or Pegboard tasks; (4) Conclusion: The magnitude of SAI and LAI does not relate to performance on the sensory and motor tasks tested. Future studies are needed to better understand whether the afferent inhibition phenomenon relates to human behavior., Competing Interests: The authors declare no conflict of interest.

Background: External beam radiotherapy (XRT) to the breast has been shown to increase complication rates in women undergoing implant-based breast reconstruction (IBBR). Owing to concerns about high complication and failure rates, our department began to favour autologous reconstructive in patients requiring XRT in 2013. This study assesses the outcomes of IBBR prior to and following this policy change., Methods: The records of all patients who underwent first-stage IBBR in 2012 and 2013 in our department were reviewed. Patients undergoing peri-operative XRT were identified. Complications and failure rates were analysed., Results: Over two years, 77 IBBRs were performed in 53 patients. In 2012, 11 patients underwent peri-operative XTR compared with five in 2013. Radiotherapy was significantly associated with higher reconstructive failure rates while pre-operative XRT was associated with more complications overall (p=0.0099). Over the two years, the number of IBBRs with any complication fell from 16 (43.2%) to 11 (27.5%) while reconstructive failure fell from six (16.2%) to four (10%)., Conclusions: Peri-operative XRT increases complication rates and reconstructive failure with IBBR. Our current policy of recommending autologous reconstruction if they have had pre-operative XRT seems to be resulting in decreased complication rates and increased reconstructive success., Competing Interests: Nil.

Transcranial magnetic stimulation (TMS) is an ideal technique for non-invasively stimulating the brain and assessing intracortical processes. By delivering electrical stimuli to a peripheral nerve prior to a TMS pulse directed to the motor cortex, the excitability and integrity of the sensorimotor system can be probed at short and long time intervals (short latency afferent inhibition, long latency afferent inhibition). The goal of this review is to detail the experimental factors that influence the magnitude and timing of afferent inhibition in the upper limb and these include the intensity of nerve and TMS delivery, and the nerve composition. Second, the neural mechanisms of SAI are discussed highlighting the lack of existing knowledge pertaining to LAI. Third, the usage of SAI and LAI as a tool to probe cognition and sensorimotor function is explored with suggestions for future avenues of research., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Anaplastic large-cell lymphoma (ALCL) has recently been reported in women with breast implants. The incidence of breast implant-related ALCL is extremely rare and most surgeons would not expect to see this disease in their career. However, the senior author has had three women present to his practice with ALCL over a 2-year period., Methods: The three patients and their presentation were reviewed to establish the presenting complaint in each case of subsequently diagnosed ALCL. Literature was reviewed to establish appropriate treatment protocols for any subsequent patients., Results: The average time between first implant placement and presentation with breast implant-associated ALCL was 13.3 years (range: 10-16 years) and age at presentation was 49 years (range: 45-53 years). Each presentation was somewhat different, being a palpable mass, a painless seroma and a painful seroma. Both patients with seroma underwent ultrasound-guided aspiration of fluid which confirmed ALCL. All patients underwent implant removal and complete capsulectomy. The patient with a mass at presentation initially declined adjuvant treatment but subsequently developed an ALCL-associated seroma and was treated with surgery and post-operative chemotherapy., Conclusion: Patients with breast implant-associated ALCL can present with different clinical signs and symptoms. Late seroma is a relatively common presentation of breast implant-associated ALCL. While firm guidelines for the management of breast implant-related ALCL are lacking, we suggest that any late seroma in the absence of infection should be managed with aspiration and cytological analysis of the fluid., (© 2015 Royal Australasian College of Surgeons.)

Since the discovery of adipose-derived stem cells (ASC) in human adipose tissue nearly 15 years ago, significant advances have been made in progressing this promising cell therapy tool from the laboratory bench to bedside usage. Standardization of nomenclature around the different cell types used is finally being adopted, which facilitates comparison of results between research groups. In vitro studies have assessed the ability of ASC to undergo mesenchymal differentiation as well as differentiation along alternate lineages (transdifferentiation). Recently, focus has shifted to the immune modulatory and paracrine effects of transplanted ASC, with growing interest in the ASC secretome as a source of clinical effect. Bedside use of ASC is advancing alongside basic research. An increasing number of safety-focused Phase I and Phase IIb trials have been published without identifying any significant risks or adverse events in the short term. Phase III trials to assess efficacy are currently underway. In many countries, regulatory frameworks are being developed to monitor their use and assure their safety. As many trials rely on ASC injected at a distant site from the area of clinical need, strategies to improve the homing and efficacy of transplanted cells are also being explored. This review highlights each of these aspects of the bench-to-bedside use of ASC and summarizes their clinical utility across a variety of medical specialties.

Aim: To assess patients' quality of life and satisfaction with individual outcomes following breast reconstructive surgery, using the BREAST-Q questionnaire., Methods: The BREAST-Q questionnaire was used to collect information on patients' satisfaction in various domains following breast reconstructive surgery. The questionnaire answers were entered into the Qscore Excel template. Scores for each domain were obtained and different comparison groups were analysed for statistical significance., Results: Overall, patients showed above average satisfaction in majority of the domains. No statistically significant difference in satisfaction was seen with breast or overall outcome when compared by type or timing of reconstruction; presence or absence of significant complication; and completed or ongoing surgery. However, some difference in satisfaction with medical and office staff by ethnicity was evident, with Europeans being more satisfied than Maori or other ethnicities., Conclusion: The BREAST-Q questionnaire is a valuable tool to provide patient satisfaction information on breast reconstruction. Our retrospective audit shows that our patients are currently satisfied with their breast and outcomes overall. We will now use this tool prospectively to assess our patients' progress and satisfaction, and improve our service delivery for our future patients.

Autologous tissue microsurgical breast reconstruction is increasingly requested by women following mastectomy. While the abdomen is the most frequently used donor site, not all women have enough abdominal tissue excess for a unilateral or bilateral breast reconstruction. A secondary choice in such women may be the transverse upper gracilis (TUG) myocutaneous flap. This study reviews our experience with TUG flap breast reconstruction looking specifically at reconstructive success rate and the requirement for secondary surgery. A total of 16 free TUG flaps were performed to reconstruct 15 breasts in eight patients over a period of five years. Data were collected retrospectively by chart review. Follow up ranged from 14 to 41 months. During the follow up period, there was one (6.3%) complete flap loss in an immediate breast reconstruction patient. Four further flaps (25%) failed in their primary aim of breast reconstruction, as they required additional significant reconstruction with either deep inferior epigastric perforator (DIEP) flaps (two flaps (12.5%), one patient) or augmentation with silicone breast implants (two flaps (12.5%), one patient), giving a successful breast reconstruction rate with the TUG flap of only 66.7%. In all of the remaining reconstructed breasts, deficient flap volume or breast contour was seen. Eight flaps were augmented by lipofilling. A total of 62.5% of the donor sites had complications, namely sensory disturbance of the medial thigh (25%) and poor scar (37.5%) requiring revision. This series demonstrates a high rate of reconstructive failure and unsatisfactory outcomes from TUG flap breast reconstruction. We feel this reinforces the necessity of adequate pre-operative patient assessment and counselling, including discussion regarding the likelihood of subsequent revisional surgery, before embarking on this form of autologous breast reconstruction., (Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Background: This study evaluated patients who underwent primary breast surgery within a single group practice from 1994 to 2009. Reoperations were divided by reoperation reason into total reoperations and implant-specific reoperations. The authors hypothesized that the implant-specific reoperation rate will provide the most accurate measurement of complications caused by the breast implant device., Methods: A total of 812 patients received the same brand of breast implant for primary breast augmentation or augmentation/mastopexy. Safety and efficacy data were recorded and complication rates were calculated. Statistics were applied using Kaplan-Meier estimated cumulative incidence calculations., Results: This study included 482 patients with saline and 330 patients with silicone implants. The most common complications included capsular contracture, rippling, rupture, infection, and hematoma. A total of 8.2 percent of patients developed Baker grade III/IV capsular contracture by 6 years. The raw incidence of rippling was 7.1 percent, and the rate was significantly increased in underweight patients with subglandular saline implants (p = 0.045). The rate of total reoperation at 1 year was 14.2 percent. While a significantly increased rate of total reoperation was seen for silicone compared with saline implants (p < 0.01), no difference was seen in the rate of implant-specific reoperation for saline compared to silicone implants (p = 0.582)., Conclusions: The use of total reoperation rates as an indication of complications of breast implants can lead to both an overestimation of implant-related complications and the inaccurate conclusion that silicone implants result in higher complication rates than saline implants. The implant-specific reoperation rate may provide a more accurate incidence of implant complications than the total reoperation rate, which includes reoperations for factors unrelated to the implant.

Background: The latissimus dorsi myocutaneous flap and implant breast reconstruction procedure has undergone many refinements over its lifetime. In fact, the authors have made many aesthetic and technical refinements to their own approach to breast reconstruction., Objectives: The authors review the historical progression of latissimus flap and breast reconstruction techniques and compare these to their own 15-year experience., Methods: A retrospective chart review was conducted for all latissimus and implant breast reconstructions performed by the senior author (MAC) from July 1994 to June 2009, for a total of 52 procedures in 31 patients. Surgical and oncological data, complications, and outcomes data were recorded., Results: The mean age of the patients at time of surgery was 47.6 years. Average mastectomy weight was 283 grams and average final implant volume was 364 cc. Average follow-up was three years, four months. Of the 52 total procedures, 34.6% were immediate breast reconstructions utilizing skin-sparing mastectomy (SSM); 13.5% of the reconstructed breasts also had preservation of the areola (areolar-sparing mastectomy [ASM]). The most common complication was donor site seroma (40.4%). Aesthetic and surgical refinements identified over the time period included the adoption of SSM and ASM techniques, immediate nipple reconstruction, the placement of an adjustable saline implant to allow for postoperative size adjustment, and implant placement in the prepectoral position. The overall latissimus dorsi implant reconstruction success rate was 94.2% (49/52)., Conclusions: The data demonstrated a successful outcome for latissimus dorsi and implant breast reconstruction for patients with a low or normal body mass index and a small (A to C cup) breast size. The aesthetic outcome of latissimus dorsi breast reconstruction has been improved over the past 15 years by the adoption of SSM and ASM techniques. Immediate nipple reconstruction and the placement of an adjustable saline implant potentially render this procedure a true single-stage reconstruction. Prepectoral implant position provides good aesthetics while preserving the subpectoral space for future management of capsular contracture if required.

A unilateral upper lateral orbital cleft, fitting the description of the extremely rare Tessier cleft number 9 is reported. The management and surgery of this patient are discussed, and the relevant literature is reviewed. The usefulness of three-dimensional computed tomography reconstructions and plastic models in planning the surgery is discussed.

After more than a century of use, fat grafting is firmly entrenched in the skill set of plastic surgeons. While macrofat grafting is relatively predictable and reliable, microfat grafting by injection is still in the stages of technical evolution. Review of the current literature suggests that revascularization may take up to 21 days to reach the center of a microfat graft. We recommend harvesting by excision (or gentle aspiration), processing by short and gentle centrifuge to separate the layers, and reinjection of the lower layer via a fine cannula (for example, 17 gauge for the face) and a 1-mL syringe with multiple passes, injecting only a tiny amount with each pass as the needle is withdrawn, to obtain the most reliable clinical outcome.