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Αλέξανδρος Γ. Σφακιανάκης

Thursday, November 18, 2021

Cross-population coupling of neural activity based on Gaussian process current source densities

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PLoS Comput Biol. 2021 Nov 17;17(11):e1009601. doi: 10.1371/journal.pcbi.1009601. Online ahead of print.

ABSTRACT

Because local field potentials (LFPs) arise from multiple sources in different spatial locations, they do not easily reveal coordinated activity across neural populations on a trial-to-trial basis. As we show here, however, once disparate source signals are decoupled, their trial-to-trial fluctuations become more accessible, and cross-population correlations become more apparent. To decouple sources we introduce a general framework for estimation of current source densities (CSDs). In this framework, the set of LFPs result from noise being added to the transform of the CSD by a biophysical forward model, while the CSD is considered to be the sum of a zero-mean, stationary, spatiotemporal Gaussian process, having fast and slow components, and a mean function, which is the sum of multiple time-varying functions distributed across sp ace, each varying across trials. We derived biophysical forward models relevant to the data we analyzed. In simulation studies this approach improved identification of source signals compared to existing CSD estimation methods. Using data recorded from primate auditory cortex, we analyzed trial-to-trial fluctuations in both steady-state and task-evoked signals. We found cortical layer-specific phase coupling between two probes and showed that the same analysis applied directly to LFPs did not recover these patterns. We also found task-evoked CSDs to be correlated across probes, at specific cortical depths. Using data from Neuropixels probes in mouse visual areas, we again found evidence for depth-specific phase coupling of primary visual cortex and lateromedial area based on the CSDs.

PMID:34788286 | DOI:10.1371/journal.pcbi.1009601

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Prevalence of Body Dysmorphic Disorder Among Rhinoplasty Candidates: A Systematic Review

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Ear Nose Throat J. 2021 Nov 18:1455613211056543. doi: 10.1177/01455613211056543. Online ahead of print.

ABSTRACT

OBJECTIVE: Body dysmorphic disorder (BDD) represents a bridge between the fields of psychiatry and cosmetic surgery. It is a psychiatric disorder involving altered body image and has been associated with cosmetic surgery. Many studies have investigated BDD following rhinoplasty. However, their findings were inconsistent, which prompted us to conduct this systemati c review to obtain strong evidence about the prevalence of BDD among rhinoplasty candidates.

METHODS: We searched the literature using electronic databases such as PubMed, Scopus, Web of Science, and others using keywords relevant to the study outcomes. We also manually examined the references of the included studies and relevant reviews to look for articles that might have been missed during the electronic search.

RESULTS: Nine articles met the inclusion criteria. We identified 7 other relevant articles; since they had been included in a review conducted in 2016, they were not included in the final list of articles. However, they were included in the discussion, and their findings have been compared with ours. The included articles resulted in a total sample of 712 rhinoplasty candidates. The estimated prevalence rates of BDD in these articles ranged from 22% to 52%, which was considered high by all the authors of the included studies.

CONCLUSION: The prevalence o f BDD among rhinoplasty candidates is high, and adequate management and interventions are needed to reduce it.

PMID:34789021 | DOI:10.1177/01455613211056543

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Comparison of auricle reconstruction with expanded flaps and auricle reconstruction with non-expanded flaps in patients with microtia: A meta-analysis

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Ear Nose Throat J. 2021 Nov 18:1455613211056550. doi: 10.1177/01455613211056550. Online ahead of print.

ABSTRACT

OBJECTIVE: We conducted this meta-analysis to compare the efficacy of these two surgical methods by comparing the incidence of major evaluation indicators.

METHODS: The databases such as PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure, Wanfang, and VIP information databases were searched.

RESULTS: The satisfaction rate of patients with auricle reconstruction using expanded flaps was 86.5%, and the satisfaction rate of patients with auricle reconstruction using non-expanded flaps was 87.9%. The incidence of postoperative hematoma was 3.2% in patients with auricle reconstruction using expanded flaps and 18.9% in patients with auricle reconstruction using non-expanded flaps. The incidence of postoperative skin necrosis was 2.2% in patients with auricle reconstruction using expanded flaps and 4.1% in patients with auricle reconstruction using non-expanded flaps. The incidence of postoperative incision infection was 3.1% in patients with auricle reconstruction using expanded flaps and 0.9% in patients with auricle reconstruction using non-expanded flaps. The incidence of cartilage framework exposure was 2.2% in patients with auricle reconstruction using expanded flaps and 1.9% in patients with auricle reconstruction using non-expanded flaps. The incidence of postoperative scar hyperplasia was 3.8% in pati ents with auricle reconstruction using expanded flaps and 3% in patients with auricle reconstruction using non-expanded flaps. The publication bias of included literature was evaluated by Egger test. There was no publication bias in this Meta-analysis (P > .05).

CONCLUSION: The auricle reconstruction using non-expanded flaps is dominant in four of the six evaluation indexes. Therefore, we believe that the auricle reconstruction using non-expanded flaps has better therapeutic effect in patients with microtia. Due to the limitations of this meta-analysis, the conclusions of this meta-analysis still need to be further verified.

PMID:34789039 | DOI:10.1177/01455613211056550

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The application of a retrograde postauricular island flap in reconstructing periorbital region defects

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J Plast Reconstr Aesthet Surg. 2021 Oct 22:S1748-6815(21)00514-3. doi: 10.1016/j.bjps.2021.09.069. Online ahead of print.

ABSTRACT

BACKGROUND: Reconstruction of periorbital region defects is thought to be one of the most challenging areas in reconstructive plastic surgery. This paper describes our experiences with the application of retrograde postauricular island flaps in reconstructing periorbital region defects.

METHODS: Between November 2008 and June 2019, 16 patients with periorbital region defects underwent treatment using a retrograde postauricular island flap. The flap is designed with two portions: 1) the pedicle segment only with the superficial temporal fascia and 2) the flap segment in the posterior auricular region with non-hair-bearing full-thickness tissue. Intraoperatively, the vascular networks between the postauricular and the superficial temporal vessels were preserved. The flap was then transferred to the rece ipt area after passing through a subcutaneous tunnel. The donor site was directly closed in the postauricular sulcus by advancing the posterior scalp flap.

RESULTS: All the periorbital region defects were reconstructed in one-stage surgery. All the flaps survived without venous congestion. The size of the harvested flaps varied from 5.0 × 2.5 cm to 7.5 × 5 cm. The colour of the transferred flaps matched the surroundings of the receipt region, and the eyelids functioned well.

CONCLUSION: A retrograde postauricular island flap is a good choice for the reconstruction of periorbital region defects. The flap can be useful for the reconstruction of the periorbital region, since it uses similar colours and textures. In addition, it permits a "one-stage" reconstruction with less conspicuous donor site scars behind the auricle.

PMID:34789431 | DOI:10.1016/j.bjps.2021.09.069

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A new aesthetic pretrichial approach for upper third-facial fractures and pathologies: The 'Crown incision'

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J Plast Reconstr Aesthet Surg. 2021 Oct 22:S1748-6815(21)00485-X. doi: 10.1016/j.bjps.2021.09.042. Online ahead of print.

ABSTRACT

BACKGROUND: The coronal incision represents the cornerstone for the treatment of upper-third maxillofacial pathologies. However, this approach leaves long scars that in numerous patients, it can cause extensive surrounding alopecia and sensory skin deficits. This clinical evidence prompted the authors to propose a full pretrichial incision, the crown incision, in order to overcome these drawbacks.

METHODS: A retrospective study was performed to investigate and report the aesthetic and functional outcomes of 15 patients treated with this new approach.

RESULTS: In the postoperative period, no major or minor complications were detected. The aesthetic evaluation of the scar by the operator and the patient showed overlapping results. The overall rating was 2.93 for the patient and 2.87 for the surgeo n, on a scale from 0 (as normal skin) to 10 (very different from normal skin). The recovery of sensitivity in the innervation territories of the supratrochlear and supraorbital nerves was found to be complete in 14 patients. In one case, the sharp/blunt discriminative sensitivity was absent in all three points assessed.

CONCLUSIONS: This study showed the crown incision to be a safe approach with an optimal recovery of scalp sensitivity and excellent aesthetic results even in bald patients. Therefore, it can be considered a valid aesthetic and effective alternative to the classic coronal approach and should form part of the craniomaxillofacial surgical armamentarium.

PMID:34789433 | DOI:10.1016/j.bjps.2021.09.042

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Outcomes of anterior interosseous nerve transfer to restore intrinsic muscle function after high ulnar nerve injury

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J Plast Reconstr Aesthet Surg. 2021 Oct 22:S1748-6815(21)00510-6. doi: 10.1016/j.bjps.2021.09.072. Online ahead of print.

ABSTRACT

Traumatic high ulnar nerve injuries have historically resulted in long-term loss of hand function due to the long re-innervation distance to the intrinsic muscles. Transfer of the anterior interosseous nerve (AIN) to the deep motor branch of the ulnar nerve (MUN) is proving promising in these patients. The purpose of this study was to evaluate the outcomes and efficacy of this procedure in our series. Eligible high ulnar nerve injury patients who underwent AIN to MUN nerve transfer were evaluated with a mean follow-up of 17 months. Data including demographics, injury details, surgical procedures, and outcomes were collected. A review of the current literature was performed for comparison. Sixteen patients had AIN to MUN transfer, mean age of 39.4 years, and a median delay from injury to nerve transfer of 0. 8 months. The injury site was above the elbow in 5 cases, at the elbow in 8 cases, and in the proximal forearm in 3 cases. The majority were sharp transection, with the remaining from blast injuries, traumatic traction, and one post-traumatic neuroma resection. Transfer was performed end-to-end in 7 cases, hemi end-to-end in 7 cases, and supercharged end-to-side in 2 cases. Five patients achieved intrinsic muscle recovery of MRC 4+ and thirteen gained MRC 3 or above. The AIN to MUN nerve transfer provides meaningful intrinsic recovery in the majority of traumatic high ulnar nerve injuries. This procedure should be routinely considered, however, warrants further research to validate the optimum technique.

PMID:34789435 | DOI:< a href="https://doi.org/10.1016/j.bjps.2021.09.072" target="_blank" rel="noopener" class="underlink bluelink">10.1016/j.bjps.2021.09.072

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Melanoma sentinel lymph node biopsy and completion lymph node dissection: A regional hospital experience

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J Plast Reconstr Aesthet Surg. 2021 Oct 22:S1748-6815(21)00518-0. doi: 10.1016/j.bjps.2021.09.077. Online ahead of print.

ABSTRACT

Completion lymph node dissection (CLND) following positive sentinel lymph node biopsy (SLNB) for cutaneous melanoma is a topic of controversy. The second Multicenter Selective Lymphadenectomy Trial (MSLT-II) suggested no survival benefit with CLND over observation amongst patients with a positive SLNB. The findings of the MSLT-II may have limited applicability to our high-risk population where nodal ultrasound and non-surgical melanoma treatment is rationed. In this regional, retrospective study, we reviewed primary melanoma, SLNB and CLND histopathological reports in the Bay of Plenty District Health Board (BOPDHB) across a 10-year period. The primary outcomes measured were size of sentinel lymph node metastases and non-sentinel node (NSN) positivity on CLND for patients with a positive SLNB. In the 157 SL NB identified, the mean sentinel lymph node metastatic deposit size was larger in BOPDHB compared with MSLT-II (3.53 vs 1.07/1.11mm). A greater proportion of BOPDHB patients (54.8%) had metastatic deposits larger than 1mm compared with MSLT-II (33.2/34.5%) and the rate of NSN involvement on CLND was also higher (23.8% vs 11.5%). These findings indicate that the BOPDHB is a high-risk population for nodal melanoma metastases. Forgoing CLND in the context of a positive SLNB may place these patients at risk.

PMID:34789434 | DOI:10.1016/j.bjps.2021.09.077

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Managing locoregional breast cancer recurrence after autologous free flap reconstruction: A retrospective review of 2,734 procedures

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J Plast Reconstr Aesthet Surg. 2021 Oct 22:S1748-6815(21)00519-2. doi: 10.1016/j.bjps.2021.09.078. Online ahead of print.

ABSTRACT

INTRODUCTION: The 5-year incidence of locoregional recurrence (LRR) after mastectomy is 3-8 %. This study examines the incidence, modes of detection, and reconstructive options after loss of index reconstruction in the largest series of autologous free flap patients who subsequently developed LRR.

METHODS: We identified patients undergoing muscle-sparing free transverse rectus abdominus muscle or deep inferior epigastric perforator flap reconstruction for breast cancer at our institution from 2005 to 2017 who subsequently developed LRR. The main outcomes were incidence of recurrence, primary mode of detection, surgical management, and patient and cancer-specific factors associated with surgical management and loss of index reconstruction.

RESULTS: The incidence of LRR in this cohort was 3% (n=66 of 2240 flaps), and 71% (n=46) of recurrences were diagnosed on physical examination. 80% (n=53) of LRR required multidisciplinary management, whereas 56% (n=37) were managed surgically. Patients with postoperative radiation prior to recurrence, metastatic disease at diagnosis, nodal positivity, and chest wall involvement were less likely to be offered surgery (all p<0.05). Twelve patients lost their index reconstruction and five required subsequent advanced chest wall reconstruction. No differences were seen in terms of location of recurrence, detection of recurrence, or mortality between flap types (all p>0.05).

CONCLUSION: Management of LRR is centered around early multidisciplinary involvement and often requires surgery. Removal of index reconstruction and/or advanced chest well reconstruction is indicated in select cases. Plastic surgeons should be aware of the indications and options that exist for management in these complex situations.

PMID:34789432 | DOI:10.1016/j.bjps.2021.09.078

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The Role of HPV in Cancer Prognosis

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In recent decades, it has become clear that most oropharyngeal squamous cell carcinomas (OPSCCs) are associated with human papillomavirus (HPV), with a distinct biology and favorable prognosis vs head and neck squamous cell carcinomas (HNSCCs) that originate in other anatomic subsites. The reasons for the superior survival outcomes and treatment responses seen in HPV-related OPSCC are not entirely well understood. However, it is known that viral oncoproteins within tumor cells can serve as a source of antigenic stimulation for immune cells w ithin the tumor microenvironment. Radiation and chemotherapy release these viral antigens from dying tumor cells, effectively turning the tumor into an in situ vaccine. These concepts are supported by the superior responses of HPV-related OPSCC to radiation, chemotherapy, and immune checkpoint inhibitors. However, the role of HPV in the prognosis of HNSCC outside the oropharynx is less clear. Fewer oral, laryngeal, and hypopharyngeal tumors are positive for HPV, although tumors at these sites are not routinely tested. Adding to the mystery, studies investigating whether these nonoropharyngeal, HPV-positive tumors are associated with improved prognosis vs their HPV-negative counterparts have shown mixed results. Tumors from other anatomic subsites of the head and neck often contain transcriptionally active virus and a nonkeratinizing, endophytic growth pattern similar to HPV-positive OPSCC, suggesting that the oncogenesis of these tumors is driven by the virus. However, collectively, these studies suggest that the association between HPV status and prognosis is not nearly as strong outside the oropharynx. In the case of cervical cancer, the effects of HPV on prognosis are also controversial, but this has been challenging to investigate because most cervical cancer cases are associated with HPV.
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Growing Public Health Concern of COVID-19 Chronic Olfactory Dysfunction

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This meta-analysis examines the scale of the public health con cern of COVID-19–related chronic olfactory dysfunction.
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Tumor Site and the Prognosis and Immunogenomics of HPV-Related Cancers

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This cohort study categorizes tumors of the head and neck and the cervix by human papillomavirus (HPV) positivity status and compares their immunogenomic landscapes and associations with survival.
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