Evidence-Based Dynamics in Rhinoplasty.

Rhinoplasty is a delicate surgical procedure that requires a thorough understanding of the dynamic interplay between the various structures of the nose. Any changes made to one part of the nose can have downstream effects on the overall harmony and appearance of the nose. For this reason, it is crucial for surgeons to be aware of these potential impacts in order to achieve predictable and aesthetically pleasing results. In this article, we aim to provide a summary of the current evidence-based conclusions on the dynamic influence of the radix, dorsum, tip, and ala during rhinoplasty. By understanding the complex relationships between these structures, surgeons can make informed decisions and achieve the best possible outcomes for their patients.

Tissue adjuncts in primary cleft palate reconstruction: A systematic review.

BACKGROUND: Tissue adjunct is non-palatal tissue used to manage tension at the defect site by providing additional coverage. This review aimed to compare outcomes of various adjuncts employed in primary palatoplasty. METHODS: A literature search was conducted of MEDLINE, EMBASE, and Cochrane Library with keywords cleft palate, palatoplasty, surgical flaps, and allografts. Data extracted included demographics, cleft severity, primary/adjunctive techniques, outcomes, and follow-up periods. Logistic regression analyses and chi-squared tests were performed to investigate associations among variables. RESULTS: A total of 1332 patients (aged 3 months-5 years) with follow-up of 1 month to 21 years were included. Cleft severity included submucous cleft (1.7%), Veau I/II (33.3%), Veau III (46.3%), and Veau IV (15.1%). Most reported techniques were Furlow (52%) and intravelar veloplasty (14.3%) for soft palate, Bardach (27.2%), and V-Y Pushback (11.1%) for hard palate. Buccal myomucosal flap (BMMF) was performed in 45.4% of cases, followed by buccal fat pad flap/graft (BFP) in 40.8% and acellular dermal matrix (ADM) in 14%. Severe clefts (Veau III/IV) were repaired more frequently with BMMF compared with ADM (p = 0.003) and BFP (p = 0.01). Oronasal fistula occurred in 3.1% of patients, and velopharyngeal insufficiency (VPI) in 4%, both associated with Veau IV (fistula: p = 0.002, VPI: p = 0.0002). No significant differences were found in fistula (p = 0.79) or VPI (p = 0.14) rates between adjuncts. In severe clefts (Veau III/IV), ADM was associated with fistula formation (p = 0.03). CONCLUSIONS: Adjuncts in primary palatoplasty may mitigate unfavorable outcomes associated with severe clefts. BMMF is superior, given its inherent tissue properties, whereas BFP is effective in reducing fistula formation.

Distinguishing Authentic Voices in the Age of ChatGPT: Comparing AI-Generated and Applicant-Written Personal Statements for Plastic Surgery Residency Application.

BACKGROUND: ChatGPT, a generative artificial intelligence model, may be used by future applicants in the plastic surgery residency match. METHODS: Ten personal statements (5 generated by ChatGPT, 5 written by applicants) were rated by 10 reviewers, blinded to the source of the essay. RESULTS: A total of a 100 evaluations were collected. There was no significant difference in ratings for readability, originality, authenticity, and overall quality (all P > 0.05) when comparing computer-generated and applicant essays. CONCLUSION: Personal statements prepared by ChatGPT are indistinguishable from essays written by actual applicants. This finding suggests that the current plastic surgery application format be reevaluated to better aid in holistic evaluation of students.

The Versatile Role of Fat Injection During Various Genioplasties.

BACKGROUND: Fat injection has become increasingly popular in aesthetic surgery, but there is a sparsity of literature regarding its role during genioplasty. In this study, we present the largest series of patients receiving fat injections to the chin for various indications. METHODS: Data were collected from January 2016 to December 2021 for patients who underwent chin fat injection for a variety of chin refinements. Patients with chin fat injection were divided into isolated genioplasty with fat injection (CF), combined facial and chin fat injection (CFC) and combined chin fat injection and osseous genioplasty (CFG). Complication rates and reoperations were compared using Fischer's exact test between each cohort. RESULTS: 181 patients were included in final analysis, with 14 patients in CF cohort, 130 patients in CFC cohort, 24 patients in CFG cohort, and 13 patients who underwent genioplasty alone. Repeat fat injections were required in 17 (9.4%) patients overall, which included 14 patients (10.8%) of CFC subcohort and three patients (12.5%) of CFG subcohort (p > 0.05). No patients who underwent genioplasty alone or CF required reoperation. There were no significant differences in complications between genioplasty alone group (0%) in comparison to CF (7.1%; p = 1.00), CFC (6.2%; p = .53), or CFG cohorts (7.7%; p = 1.00). CONCLUSION: Fat injection can safely correct minor chin deficiency or asymmetry, as either an isolated procedure or in combination with osteotomies. Additionally, fat injection enables advancement of the caudal segment to achieve superior outcomes by preventing unaesthetic deepening of labiomental groove which will not be advanced during sliding osteotomy. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Common Dorsal Flaws Following Preservation Rhinoplasty: A Systemic Analysis.

BACKGROUND: There has recently been a resurgence of interest in preservation rhinoplasty (PR) for dorsal hump elimination or dorsal projection reduction. However, no studies have scrutinized aesthetic outcomes to identify common pattern of flaws seen in published images to aid those with ardent enthusiasm for this technique to become aware of the frequency of these flaws and find ways to reduce imperfections. METHODS: A systematic literature review was performed using search terms ("preservation" OR "let down", "push down") AND "rhinoplasty" on PubMed, Cochrane, SCOPUS, and EMBASE databases for studies between January 2000 and December 2022. Patient images from these studies were analyzed by three reviewers (MWW, IAC, and BG) for dorsal flaws. Raw interrater agreement percentage and Krippendorff's alpha were calculated to determine interrater reliability. A descriptive and comparative analysis with Fisher's exact test was performed for the aggregate data. RESULTS: There were 59 patient images with 464 views from 24 studies included for final analysis. Optimal dorsal aesthetic lines (DAL) were noted in 12 patients (20.3%), while optimal profile was observed in 15 patients (25.4%) (p = 0.66). Combined ideal front and profile view of dorsum was not observed on any patients. The most common flaws were DAL irregularities (n = 45; 78.0%), dorsal deviation (n = 32, 54.2%), and residual hump (n = 25, 42.4%). There was excellent interrater agreement. CONCLUSIONS: While PR may have some advantages, it has shortcomings in outcomes, particularly dorsal irregularities, dorsal deviation, and residual humps. Awareness of these imperfections may compel those performing this procedure to modify their techniques and improve their results. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Exploring the Resurgence of the Preservation Rhinoplasty: A Systematic Literature Review.

INTRODUCTION: The underlying principles of preservation rhinoplasty (PR) center around maintaining the soft tissue envelope, dorsum, and alar cartilage through surgical manipulations and tip suture techniques. In particular, the let-down (LD) and push-down (PD) techniques have been described, although reports of indications and outcomes in the literature are sparse. METHODS: A systematic review of the literature was performed using search terms "preservation" OR "let down" OR "push down" AND "rhinoplasty" on PubMed, Cochrane, SCOPUS, and EMBASE databases. Patient demographic information, operative details, and surgical outcomes were recorded. Sub-cohorts for patients who underwent LD and PD techniques were analyzed utilizing Fischer's exact test for categorical variables and Student's t test for continuous variables. RESULTS: Overall, there were 5967 PR patients in 30 studies in the final analysis, with 307 patients in the PD cohort and 529 patients in the LD cohort. The Rhinoplasty Outcome Evaluation Questionnaire showed a significant increase of patient satisfaction after PR compared to before PR (62.13 vs 91.14; p < 0.001). There was a significantly lower rate of residual dorsal hump or recurrence of 1.3% (n = 4) in the PD when compared to 4.6% (n = 23) in LD cohorts (p = 0.02). The revision rate of PD (0%, n = 0) was also significantly lower than that of LD (5.0%, n = 25) (p < 0.001). CONCLUSION: Based on these published articles, it seems that preservation rhinoplasty is safe and efficacious procedure with improved dorsal aesthetic lines, reduced dorsal contour irregularities, and claimed excellent patient satisfaction. In particular, the PD technique has fewer reported complications and revisions than LD approach, although PD is often indicated in patients with smaller dorsal humps. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Temporalis Myofascial Flap and Conchal Bowl Cartilage Grafting for Temporomandibular Joint Arthritis.

Temporomandibular joint (TMJ) arthritis arises from a multitude of etiologies; however, there is no consensus definitive treatment. The complication profile of artificial TMJs is well known, and outcomes are variable and are reserved for salvage attempts. This case details a patient with persistent traumatic TMJ pain, arthritis, and single-photon emission computed tomography scan of potential nonunion. The present study reports on the first novel use of an alternative composite myofascial flap to help arthritic TMJ pain. This study details the successful use of a temporalis myofascial flap and conchal bowl autologous cartilage graft in posttraumatic TMJ degeneration.

Preinjury Social Determinants of Health Disparities Predict Postinjury Psychosocial Conditions in Adult Traumatic Brachial Plexus Injuries.

BACKGROUND: Adult traumatic brachial plexus injuries (TBPIs) are life-altering events that can have detrimental effects on a patient's quality of life. OBJECTIVE: To examine how social determinants of health (SDOH) disparities influence the risk of developing new psychosocial conditions after TBPIs in previously psychiatric-naïve patients. METHODS: Between January 2010 and June 2019, a retrospective analysis was performed using PearlDiver's Mariner, an all-payer claims database, to create 3 cohorts: TBPI disparity cohort: patients with TBPI and presence of at least 1 SDOH disparity before injury, TBPI without disparity cohort: patients with TBPI and the absence of any SDOH disparity, and control cohort: patients without TBPIs. RESULTS: The matched population analyzed in this study consisted of 1176 patients who were equally represented in the TBPI disparity cohort (n = 392, 33.33%), TBPI without disparity cohort (n = 392, 33.33%), and control cohort (n = 392, 33.33%). A total of 301 patients developed any psychosocial condition with 4 years of their injury. Patients in the TBPI disparity cohort had significantly higher rates of developing any psychosocial condition (31.12%, P < .0005), depression (22.70%, P = .0032), anxiety (18.62%, P = .0203), drug abuse (7.91%, P = .0060), and alcohol abuse (4.85%, P = .03499) when compared with the other cohorts. Furthermore, the disparity cohort carried a significantly increased risk of developing any psychosocial condition (hazard ratio 1.42, 95% CI 1.09-1.86). The rates of suicide attempt, post-traumatic stress disorder, and divorce did not significantly differ between groups. CONCLUSION: TBPI patients with SDOH disparities are at increased risk of developing new-onset psychosocial conditions, such as depression, anxiety, drug abuse, and alcohol abuse. Level of Evidence: Prognostic Level III.

Nipple-Sparing Gigantomastia Breast Reduction: A Systematic Review.

INTRODUCTION: There remains an unclear definition of the term "gigantomastia," with many studies using different parameters and measurements. Currently, the operative management and patient education for gigantomastia are outdated. The historical teaching that a free nipple graft is necessary in elongated pedicles to avoid nipple necrosis may not be factual. The principal goal of our review aims to determine the safety of nipple-sparing breast reductions on large ptotic breasts via complication rate analysis. METHODS: The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines of conduct for systematic review and meta-analysis. In October 2021, PubMed was used to search the US National Library of Medicine database. Rayyan Intelligent Systematic Review aided in screening studies by title then abstract. If inclusion criteria were met, the entire article was reviewed. RESULTS: Twenty-two articles satisfied the inclusion and exclusion criteria. The study was composed of 1689 total patients with a mean body mass index of 32.9 (±3.4). Mean midclavicle-to-nipple distance and resection weight per breast was 39 cm (±3.8) and 1423.8 g (±268.9), respectively. A Wise pattern was preferred in 77.3% of the studies, with an inferior (45.5%) and superomedial (45.5%) pedicle used most commonly. Complete nipple areolar complex necrosis (1.7%) was found in 4 studies, whereas partial (5.9%) was observed in 11. More common complications included delayed wound healing (17.4%), surgical site infection (14.3%), seroma (10.5%), scar hypertrophy (9.9%), and wound dehiscence (9.2%). CONCLUSION: Nipple-sparing breast reduction surgery can be safely performed on hypertrophic and severely ptotic breasts with nipple areolar complications, such as partial or complete nipple areolar complex loss, at a rate less than previously believed.

Orthognathic Surgery in Ehlers-Danlos Syndrome: Review of the Literature and Case Report.

EDS (Ehlers-Danlos Syndrome) is a heterogenous group of inheritable connective tissue disorders that commonly precludes patients from being elective surgical candidates. Patients with EDS are at a higher risk of increased bleeding, delayed wound healing, and temporomandibular joint pain refractory to treatment. Historically, patients with EDS and TMJ disorders are considered inappropriate surgical candidates due to a higher risk of delayed wound healing, increased risk for uncontrolled post-surgical bleeding, and unsubstantiated outcomes in regards to elective orthognathic surgery. A review of the literature demonstrates a paucity of data accounting the use of orthognathic surgery and maxillary-mandibular advancement in patients with EDS. The present study reports on the use of orthognathic double jaw surgery in a patient with a known diagnosis of hypermobile EDS, history of TMJ subluxation and pain. This case describes a 47-year-old woman with a history of hypermobile EDS who presented with Angle Class II malocclusion, Class II skeletal pattern, and clockwise rotation of the occlusal plane associated with pain at the bilateral TMJs. She underwent maxillary-mandibular advancement with counterclockwise rotation of the occlusal plane and genioplasty. The surgery was without complications, and at 22 months follow up, the patient healed uneventfully with improvement of pain and range of motion. This case report demonstrates that with diligent patient selection, orthognathic surgery in patients with EDS can be safe and effective and should not be an absolute contraindication.

A meta-analysis of functional outcomes in rat sciatic nerve injury models.

INTRODUCTION: Rat sciatic nerve injury (PNR) is the most utilized model in studies on peripheral nerve regeneration. However, large animal models are increasingly favored based on the assumption that nerve regeneration in rodents achieves more favorable outcomes than in humans. The purpose of this meta-analysis was to investigate which rat PNR models are more stringent and should be used before utilizing large animal experimentation. METHODS: A PRISMA-guided meta-analysis of the English literature regarding functional outcomes in rat peripheral nerve injury models was conducted. Outcomes of five basic scenarios: (1) transected nerve/negative control, (2) transection with primary microsurgical repair, (3) isogenic/autologous grafts, (4) acellular-allogenic grafts, and (5) limb transplantation were compared to sciatic nerves without any intervention/positive control. Outcomes were compared using Sciatic Functional Index (SFI). Log-based projections were generated and evaluated using mean squared error (MSE), one-way-ANOVA, and Tukey-HSD post-hoc analysis. RESULTS: In total, 167 articles met the inclusion criteria. The earliest manifestations of motor recovery were encountered in the transection and primary repair group (p <.0005). There was a significant difference in recovery time and degree of recovery between all surgical models (p <.0005). At 24 weeks, the SFI in hindlimb transplantation group was significantly worse than all other groups (-74.07 ± 2.74, p <.0005). Autografts smaller than 10 mm recovered sooner than autografts longer than 10 mm (p = .021) and autografts recovered faster than allografts. CONCLUSION: This meta-analysis does not support the belief that neuro-regeneration is exceptional in transection models. These models remain adequate to provide translatable information and should initially be used in investigational studies.

Alemtuzumab Induction Is Associated With Equalization of Graft Outcomes Between Elderly and Nonelderly Kidney Transplant Recipients: A Single-Center Report.

OBJECTIVES: Alemtuzumab (monoclonal anti-CD52 antibody) provides profound lymphocyte depletion and offers numerous advantages as an induction agent. Elderly recipients (> 65 years old) traditionally have inferior posttransplant outcomes versus younger recipients. We investigated short-term and long-term patient and graft survival rates following alemtuzumab induction in elderly recipients. MATERIALS AND METHODS: This retrospective analysis, which included 676 renal allograft transplant recipients with alemtuzumab induction, was conducted at the University of Toledo Medical Center between March 2006 and November 2015. We used 2-sided t test, Pearson chi-square test, Fisher exact test, and Cox proportional hazard regressions with 95% confidence interval for analyses. P < .05 was significant. RESULTS: Elderly recipients were more likely to receive a kidney from an inferior donor (deceased donor: 82% vs 72.4%; P = .030) and have higher mean kidney donor profile index (46.2 vs 38.4; P = .024) than nonelderly recipients. Elderly recipients were more likely to experience delayed graft function (15.1% vs 8.5%; P = .038). Elderly recipients demonstrated death-censored graft survival (1 year: 95.4% vs 93.1%; 3 years: 88.5% vs 93.3%; 5 years: 83.1% vs 86.4%) and rejection rates (1 year: 19.8% vs 21.2%; 3 years: 22.1% vs 25.3%; 5 years: 23.8% vs 26.9%) similar to nonelderly recipients. Elderly recipients had significantly higher overall mortality rates than recipients under 65 years old (29.8% vs. 13.2%; P = .001). Although 1-year patient survival was similar to younger recipients (94.8% vs 96.3%; P = .431), 3-year (80.0% vs 91.5%; P = .006) and 5-year (72.9% vs 86.2%; P = .19) rates were significantly decreased in elderly recipients. CONCLUSIONS: Elderly age is not a predictor of rejection or death-censored graft loss in individuals who receive alemtuzumab induction. Despite elevated overall mortality, elderly recipients induced with alemtuzumab demonstrated rejection, graft, and short-term patient survival rates similar to younger recipients.

Alemtuzumab Induction Is Associated With an Equalization of Outcomes Between White and African American Kidney Transplant Recipients.

OBJECTIVES: Our aim was to assess outcomes in White and African American kidney transplant recipients after induction with alemtuzumab. MATERIALS AND METHODS: We performed a retrospective study of 464 patients who received deceased-donor kidney transplants and were induced with alem-tuzumab between March 2006 and May 2015. We evaluated ethnic influences on patient and graft survival, delayed graft function, allograft failure, and rejection. RESULTS: There were 337 White (67.3%) and 127 African American (25.3%) patients. We observed no significant differences in 1-, 3-, 5-, and 7- year death-censored graft survival. We also observed no significant differences in 1-, 3-, and 5-year patient survival rates. Having African American ethnicity was not a significant predictor of rejection, graft survival, or patient survival. CONCLUSIONS: Our results indicate that recipient ethnicity is not a predictor of rejection, graft survival, or patient survival. White and African American kidney transplant recipients induced with alemtuzumab experienced an equalization of outcomes.

Simultaneous Pancreas and Kidney Transplantation is Associated With Inferior Long-Term Outcomes in African Americans.

OBJECTIVES: Simultaneous pancreas and kidney transplant (SPK) is the most effective treatment for patients with type 1 diabetes mellitus and renal failure. However, the effect of ethnicity on SPK outcomes is not well understood. METHODS: We studied the influence of recipient ethnicity on SPK using the United Network for Organ Sharing database. A retrospective review of 20,196 SPK patients from 1989 to 2014 was performed. The recipients were divided into 4 groups: 15,833 whites (78.40%), 2708 African Americans (AA) (14.39%), 1456 Hispanics (7.21%), and 199 Asians (0.99%). RESULTS: Hispanics and Asians experienced the best overall graft and patient outcomes. Both groups demonstrated significantly superior graft and patient survival rates compared with whites at 1, 3, 5, 10, and 15 years (all P < 0.0001). African Americans experienced significantly superior 1- and 3-year patient survival compared with whites (both P < 0.0001). African Americans also experienced significantly superior 1-year kidney and pancreas graft survival compared with whites (P < 0.0001). However, AA experienced significantly inferior patient and allograft outcomes for all other time points compared with whites. CONCLUSIONS: Based on United Network for Organ Sharing data from 1989 to 2014, AA have worse long-term patient and graft survival rates compared with whites, Hispanics, and Asians undergoing SPK.

Improvements in Outcomes for Ethnic Minorities During the Share 35 Era Are Not Due to Decreased Rates of Early Graft Loss.

OBJECTIVES: Our aim was to investigate the effects of the Share 35 policy on outcomes in ethnic minorities and recipients who experienced early graft failure. MATERIALS AND METHODS: We analyzed donor and recipient data from the United Network for Organ Sharing database before (June 6, 2011 to June 18, 2013) and after (June 18, 2013 to June 30, 2015) implementation of Share 35. Graft and patient survival outcomes were compared. RESULTS: There were significant differences in 1- and 2-year graft and patient survival rates between ethnicities pre-Share 35 (P = .03, P < .001, P = .01, P < .001, respectively). There were no significant differences in 1- and 2-year graft and patient survival between ethnicities post-Share 35 (P = .268, P = .09, P = .343, P = .087, respectively). There were no differences in early graft failure rates pre- and post-Share 35 at 7 days (2.1% vs 2.0; P = .71) and 30 days (4.0% vs 3.8%; P = .47) after transplant, with a decreased early graft failure rate shown at 90 days after transplant (6.8% vs 5.8%; P = .003). When analyzed separately, the low Model for End-Stage Liver Disease (score of < 35) and the high Model for End-Stage Liver Disease recipients (score of ≥ 35) both exhibited reduced early graft failure rates post-Share 35 (6.1% vs 5.3% and 10.8% vs 7.8%, respectively; P < .05). CONCLUIONS: Share 35 was associated with a short-term reduction in ethnic disparities. Most ethnic groups experienced improved survival in the Share 35 era. Share 35 was not associated with an increase in early graft failure and is an efficacious policy with regard to short-term outcomes.

Patient Satisfaction With an Early Smartphone-Based Cosmetic Surgery Postoperative Follow-Up.

BACKGROUND: While prevalent in everyday life, smartphones are also finding increasing use as a medical care adjunct. The use of smartphone technology as a postoperative cosmetic surgery adjunct for care has received little attention in the literature. OBJECTIVES: The purpose of this effort was to assess the potential efficacy of a smartphone-based cosmetic surgery early postoperative follow-up program. Specifically, could smartphone photography provided by the patient to the plastic surgeon in the first few days after surgery allay patient's concerns, improve the postoperative experience and, possibly, detect early complications? METHODS: From August 2015 to March 2016 a smartphone-based postoperative protocol was established for patients undergoing cosmetic procedures. At the time of discharge, the plastic surgeon sent a text to the patient with instructions for the patient to forward a postoperative photograph of the operated area within 48 to 72 hours. The plastic surgeon then made a return call/text that same day to review the patient's progress. A postoperative questionnaire evaluated the patients' postoperative experience and satisfaction with the program. RESULTS: A total of 57 patients were included in the study. Fifty-two patients responded to the survey. A total of 50 (96.2%) patients reported that the process improved the quality of their postoperative experience. The protocol allowed to detect early complications in 3 cases. The physician was able to address and treat the complications the following day prior to the scheduled clinic follow up. CONCLUSIONS: The smartphone can be effectively utilized by the surgeon to both enhance the patient's postoperative experience and alert the surgeon to early postoperative problems. LEVEL OF EVIDENCE: 4.

Surgical Management of Mandibular Intraosseous Schwannomas.

Intraosseous schwannomas of the mandible are rare tumors that usually arise from peripheral nerve sheaths of the main trunk or branches of the inferior alveolar nerve (IAN).A systematic review of the English literature through PubMed was conducted from 1945 to 2016. Forty-nine patients of mandibular intraosseous schwannomas were identified. The most common location of the tumor was the posterior mandible (61.2%). There were 28 patients in whom the tumor involved the IAN (57.1%). The most commonly performed procedures included enucleation through a mucoperiosteal flap and a bone window (73%), curettage (10%), segmental mandibulectomy (10%), and sagittal split ramus osteotomy (6%). The recurrence rate was 6%: all 3 recurrent patients occurred in the posterior area. The authors report a 72-year-old female with a schwannoma of the IAN which was removed through a sagittal split of the mandible, although there was a bony defect of the external cortex after biopsy of the lesion. The nerve was reconstructed with a sural nerve graft.Due to the slow growing nature and encapsulation of schwannomas, surgical resection seems the best treatment with optimal functional outcomes and low recurrence rate even with a minimally invasive approach. Sagittal split ramus osteotomy and segmental mandibulectomy are reserved to large or posterior lesions to aid with radical resection or improve exposure and reconstruction.