Perforator-Based Cross-Midline Flaps of the Trunk: A Paradigm Shift in Flap Design.

BACKGROUND: The traditional design for truncal perforator flaps is ipsilateral without midline decussation. The presumed rationale is to minimize the risk of distal flap necrosis. In this article, the authors present their experience and results with contralateral truncal perforator flaps designed and raised crossing the midline. METHODS: This retrospective analysis included 43 patients (25 men and 18 women) who underwent reconstructive surgery from 1984 to 2021 using a contralateral flap design crossing the midline in the anterior trunk and upper back. Considerations included pathology, location, and the dimensions of the defect and flap. Arithmetic and weighted means with their 95% confidence intervals were estimated to compare ipsilateral and contralateral techniques. RESULTS: Contralateral flaps used included the internal mammary perforator flap ( n = 28) superficial superior epigastric artery flap ( n = 8), superior epigastric perforator flap ( n = 2), and the second or ninth dorsal intercostal artery perforator flap ( n = 5). All of these flaps, excluding the superficial superior epigastric artery flap, demonstrated length and coverage surface averages that were significantly greater than those of traditional ipsilateral flaps. However, with the contralateral superficial superior epigastric artery, both measures were statistically similar to those of traditional ipsilateral flaps. CONCLUSION: The anatomical variation design suggests that the trunk midline is not a barrier and that perforator flaps in these two regions may be raised on different longitudinal axes without compromising vitality. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Outcomes of plastic surgical reconstruction in extremity and truncal soft tissue sarcoma: Results from the US Sarcoma Collaborative.

BACKGROUND: This study aimed to define how utilization of plastic surgical reconstruction (PSR) affects perioperative outcomes, locoregional recurrence-free survival (LRRFS), and overall survival (OS) after radical resection of extremity and truncal soft tissue sarcoma (ETSTS). The secondary aim was to determine factors associated with PSR. METHODS: Patients who underwent resection of ETSTS between 2000 and 2016 were identified from a multi-institutional database. PSR was defined as complex primary closure requiring a plastic surgeon, skin graft, or tissue-flap reconstruction. Outcomes included PSR utilization, postoperative complications, LRRFS, and OS. RESULTS: Of 2750 distinct operations, 1060 (38.55%) involved PSR. Tissue-flaps (854, 80.57%) were most commonly utilized. PSR was associated with a higher proportion of R0 resections (83.38% vs. 74.42%, p < 0.001). Tissue-flap PSR was associated with local wound complications (odds ratio: 1.81, confidence interval: 1.21-2.72, p = 0.004). Neither PSR nor postoperative complications were independently associated with LRRFS or OS. High-grade tumors (1.60, 1.13-2.26, p = 0.008) and neoadjuvant radiation (1.66, 1.20-2.30, p = 0.002) were associated with the need for PSR. CONCLUSION: Patients with ETSTS undergoing resection with PSR experienced acceptable rates of complications and a higher rate of negative margins, which were associated with improved LRRFS and OS. High tumor grade and neoadjuvant radiation were associated with requirement of PSR.

Full torso and limited-domain computer models for epicardial pulsed electric field ablation.

BACKGROUND AND OBJECTIVES: Pulsed Electric Field (PEF) ablation has been proposed as a non-thermal energy to treat atrial fibrillation (AF) by ablation of ganglionated plexi using the epicardial approach. The electric field distribution at the target site (heart) and its surroundings has not yet been assessed previously, using epicardial ablation technique. Our objective was to develop computational models, incorporating the real anatomy of the heart and the patient's torso, to assess the electric field distribution when applying epicardial monopolar PEF. METHODS: A novel 3D realistic full torso model was built with the multi-electrode ablation device placed on the epicardium and a dispersive pad on the patient's back to evaluate the electric field distribution. The 400 V/cm isoline was used to estimate the 'PEF-zone'. A 3D limited-domain model was also built including only the region of interest around the ablation device to assess its validity in comparison with the full torso model. RESULTS: The electrical field is mainly limited to the target site (PEF-zone with lengths of 25.79 to 29.00 mm, depths of 5.98-7.02 mm and maximum widths of 8.75-10.57 mm) and is practically negligible in adjacent organs (<30 V/cm and <36 V/cm in oesophagus and lungs, respectively). The electrical currents ranged from 3.67 A to 7.44 A. The 3D limited-domain model provided a similar electric field distribution to those obtained from the 3D full torso models (differences < 0.5 mm in PEF-zone depth). CONCLUSIONS: Computational results suggest that PEF-zone is very focused around the ablation catheter. Limited-domain models offer similar results in terms of PEF-zone size, reducing the complexity of the modelling.

Structural Preservation Rhinoplasty: A Hybrid Approach.

SUMMARY: Structural preservation rhinoplasty merges two popular philosophies of rhinoplasty-structure rhinoplasty and preservation rhinoplasty-in an effort to maximize patient outcomes, aesthetics, and function. This allows the surgeon to both preserve the favorable attributes of the nose, and also to structure the nasal tip and dorsum with grafts to maximize contour and support. The concept of dorsal preservation is to preserve favorable dorsal aesthetic lines without the creation of an "open roof." However, the addition of some structure concepts can expand the utility of dorsal preservation in primary rhinoplasty patients. The authors discuss these structure concepts and their applicability to dorsal preservation.

Novel Computer-Aided Diagnosis Software for the Prevention of Retained Surgical Items.

BACKGROUND: Retained surgical items are a serious human error. Surgical sponges account for 70% of retained surgical items. To prevent retained surgical sponges, it is important to establish a system that can identify errors and avoid the occurrence of adverse events. To date, no computer-aided diagnosis software specialized for detecting retained surgical sponges has been reported. We developed a software program that enables easy and effective computer-aided diagnosis of retained surgical sponges with high sensitivity and specificity using the technique of deep learning, a subfield of artificial intelligence. STUDY DESIGN: In this study, we developed the software by training it through deep learning using a dataset and then validating the software. The dataset consisted of a training set and validation set. We created composite x-rays consisting of normal postoperative x-rays and surgical sponge x-rays for a training set (n = 4,554) and a validation set (n = 470). Phantom x-rays (n = 12) were prepared for software validation. X-rays obtained with surgical sponges inserted into cadavers were used for validation purposes (formalin: Thiel's method = 252:117). In addition, postoperative x-rays without retained surgical sponges were used for the validation of software performance to determine false-positive rates. Sensitivity, specificity, and false positives per image were calculated. RESULTS: In the phantom x-rays, both the sensitivity and specificity in software image interpretation were 100%. The software achieved 97.7% sensitivity and 83.8% specificity in the composite x-rays. In the normal postoperative x-rays, 86.6% specificity was achieved. In reading the cadaveric x-rays, the software attained both sensitivity and specificity of >90%. CONCLUSIONS: Software with high sensitivity for diagnosis of retained surgical sponges was developed successfully.

The use of statistical modelling to identify important parameters for the shape of the torso following surgery for adolescent idiopathic scoliosis.

The surgical strategy in adolescent idiopathic scoliosis (AIS) aims to recreate the symmetry of the torso. This requires the minimisation of both the size of the scoliosis and the angulation between the sides of the torso, along with the recreation of a normal thoracic kyphosis. This study uses predictive modelling to identify the significance of the value of the pre-operative parameters, and the change in the magnitude of the parameters as a result of an operation on the shape of the torso using the 'most prominent points'; two areas of maximum prominence on either side of the spine with x, y and z coordinates. The pre-operative values, and the change in magnitude between the pre and post-operative values, for scoliosis, kyphosis and skin angulation from a group of Lenke 1 convex to the right AIS were analysed with measures collected using Integrated Spine Imaging System 2 surface topography and compared with those without visible spinal deformity. The models best explained the z coordinate and least well explained the x coordinate, although there was a contribution to all of the models that remained unexplained. The parameters that affected the position of the coordinates in the model differed between the models. This confirms that surgically altering the shape of the spine and torso whilst correcting an AIS does not lead to a symmetrical torso. There are as yet, undefined factors which contribute to the shape of the torso and which if identified and corrected surgically would lead to greater symmetry post-operatively.

Comparison of the 7th and 8th version of the AJCC classification system for soft tissue sarcomas of extremities and trunk in patients with localised, intermediate or high-grade disease treated at European tertiary sarcoma centres.

BACKGROUND: The updated 8th version of the AJCC-staging system for soft tissue sarcomas (STS) has been criticised for omitting tumour depth as category-defining variable and eventually not improving prognostic accuracy in comparison to the 7th version. This study aimed at investigating the prognostic accuracy of both AJCC-versions in STS-patients treated at European tertiary sarcoma centres. METHODS: 1032 patients (mean age: 60.7 ± 16.3 years; 46.0% [n = 475] females; median follow-up: 38.6 months), treated at five tertiary sarcoma centres for localised, intermediate or high-grade STS of extremities and trunk were retrospectively included. Uni- and multivariate Cox-regression models and Harrell's C-indices were calculated to analyse prognostic factors for overall survival (OS) and assess prognostic accuracy. RESULTS: In univariate analysis, prognostic accuracy for OS was comparable for both AJCC-versions (C-index: 0.620 [8th] vs. 0.614 [7th]). By adding margins, age, gender, and histology to the multivariate models, prognostic accuracy of both versions could be likewise improved (C-index: 0.714 [8th] vs. 0.705 [7th]). Moreover, tumour depth did not significantly contribute to prognostic accuracy of the 8th version's multivariate model (C-index for both models: 0.714). Stratification into four main T-stages based on tumour size only, as implemented in the 8th version, significantly improved prognostic accuracy between each category. However, T-stages as defined in the 7th version had poorer discriminatory power (C-index: 0.625 [8th] vs. 0.582 [7th]). CONCLUSION: Both AJCC-versions perform equally well regarding prognostic accuracy. Yet, simplification of the 8 th version by omitting tumour depth as T-stage-defining parameter, whilst emphasizing the importance of tumour size, should be considered advantageous.

Random pattern hatchet flap as a reconstructive tool in the treatment of pressure sores: clinical experience with 36 patients.

INTRODUCTION: Pressure sores represent a reconstructive challenge, and the high recurrence rate and need for reoperations should always be considered. Sacrifice of muscle and fascia in primary reconstruction may compromise options for future repairs. The objective of this study was to evaluate the reliability of muscle- and fascia-sparing random pattern hatchet flap reconstruction of pressure sores in different body regions. METHODS: From November 2017 to December 2019, 36 participants with grade III and IV pressure sores underwent random pattern hatchet flap reconstruction. Early postoperative complications and flap survival were evaluated in follow up for 6-12 months. RESULTS: Thirty-six participants with an age range of 15 to 67 years who presented with pressure sores (13 sacral, 12 ischial, 10 trochanteric, and 1 scapular) underwent surgery. Complete healing of sores was observed within 21 days of surgery in 32 cases and within 30 days for the remaining four cases. Postoperative complications (11.2%) were recorded in only four participants: two experienced partial wound dehiscence, one seroma developed in a trochanteric case, and there was one infection in a sacral sore. CONCLUSIONS: Random pattern hatchet flap is a reliable tool that results in minimal complications for treatment of pressure sores of limited dimensions.

Complete pathological response to neoadjuvant treatment is associated with better survival outcomes in patients with soft tissue sarcoma: Results of a retrospective multicenter study.

BACKGROUND: Locally advanced soft tissue sarcoma (STS) management may include neoadjuvant or adjuvant treatment by radiotherapy (RT), chemotherapy (CT) or chemoradiotherapy (CRT) followed by wide surgical excision. While pathological complete response (pCR) to preoperative treatment is prognostic for survival in osteosarcomas, its significance for STS is unclear. We aimed to evaluate the prognostic significance of pCR to pre-operative treatment on 3-year disease-free survival (3y-DFS) in STS patients. METHODS: This is an observational, retrospective, international, study of adult patients with primary non-metastatic STS of the extremities and trunk wall, any grade, diagnosed between 2008 and 2012, treated with at least neoadjuvant treatment and surgical resection and observed for a minimum of 3 years after diagnosis. The primary objective was to evaluate the effect of pCR. (≤5% viable tumor cells or ≥95% necrosis/fibrosis) on 3y-DFS. Effect on local recurrence-free survival (LRFS), distant recurrence-free survival (MFS) overall survival (OS) at 3 years was also analyzed. Statistical univariate analysis utilized chi-square independence test and odds ratio confidence interval (CI) estimate, multivariate analysis was performed using LASSO. RESULTS: A total of 330 patients (median age 56 years old, range:19-95) treated by preoperative RT (67%), CT (15%) or CRT (18%) followed by surgery were included. pCR was achieved in 74/330 (22%) of patients, of which 56/74 (76%) had received RT. 3-yr DFS was observed in 76% of patients with pCR vs 61% without pCR (p < 0.001). Multivariate analysis showed that pCR is statistically associated with better MFS (95% CI, 1.054-3.417; p = 0.033), LRFS (95% CI, 1.226-5.916; p = 0.014), DFS (95% CI, 1.165-4.040; p = 0.015) and OS at 3 years (95% CI, 1.072-5.210; p = 0.033). CONCLUSIONS: In a wide, heterogeneous STS population we showed that pCR to preoperative treatment is prognostic for survival.

Free Flap Reconstruction of Posterior Trunk Soft-Tissue Defects: Single-Institution Experience and Systematic Literature Review.

BACKGROUND: The posterior trunk is a technically demanding location for microvascular free tissue transfer. In this study, the authors report their own institutional experience with soft-tissue free flap reconstruction of the posterior trunk and provide a systematic review of the literature regarding this uncommon clinical scenario. METHODS: A systematic review was performed using the PubMed database in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A single-institution retrospective review was also performed including all patients who received a soft-tissue free flap for a posterior trunk defect between 1990 and 2019. RESULTS: The database search yielded 15 articles, representing 61 patients; the most commonly used flap was the latissimus dorsi (45.9 percent) and the most commonly reported defect location was the lumbosacrum (42.3 percent). Retrospective review of the authors' database identified 26 patients, with the latissimus dorsi being the most common flap and the sacrum the most common defect site. The authors' institutional case series showed a 30.7 percent major complication rate and 7.7 percent total flap loss rate; 38.4 percent of flaps required vein grafting. CONCLUSIONS: In this study, the authors provided a systematic literature review and described their own long-term institutional experience with these rare and difficult reconstructions. Although the overall complication rate is high, these reconstructions are frequently necessary, and an algorithmic approach can improve outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Comparison of Augmented Reality Display Techniques to Support Medical Needle Insertion.

Augmented reality (AR) may be a useful technique to overcome issues of conventionally used navigation systems supporting medical needle insertions, like increased mental workload and complicated hand-eye coordination. Previous research primarily focused on the development of AR navigation systems designed for specific displaying devices, but differences between employed methods have not been investigated before. To this end, a user study involving a needle insertion task was conducted comparing different AR display techniques with a monitor-based approach as baseline condition for the visualization of navigation information. A video see-through stationary display, an optical see-through head-mounted display and a spatial AR projector-camera-system were investigated in this comparison. Results suggest advantages of using projected navigation information in terms of lower task completion time, lower angular deviation and affirmative subjective participant feedback. Techniques requiring the intermediate view on screens, i.e. the stationary display and the baseline condition, showed less favorable results. Thus, benefits of providing AR navigation information compared to a conventionally used method could be identified. Significant objective measures results, as well as an identification of advantages and disadvantages of individual display techniques contribute to the development and design of improved needle navigation systems.

A closer look at the natural history and recurrence patterns of high-grade truncal/extremity leiomyosarcomas: A multi-institutional analysis from the US Sarcoma Collaborative.

BACKGROUND/OBJECTIVE: Natural history and outcomes for truncal/extremity (TE) soft tissue sarcoma (STS) is derived primarily from studies investigating all histiotypes as one homogenous cohort. We aimed to define the recurrence rate (RR), recurrence patterns, and response to radiation of TE leiomyosarcomas (LMS). METHODS: Patients from the US Sarcoma Collaborative database with primary, high-grade TE STS were identified. Patients were grouped into LMS or other histology (non-LMS). Primary endpoints were locoregional recurrence-free survival (LR-RFS), distant-RFS (D-RFS), and disease specific survival (DSS). RESULTS: Of 1215 patients, 93 had LMS and 1122 non-LMS. In LMS patients, median age was 63 and median tumor size was 6 cm. In non-LMS patients, median age was 58 and median tumor size was 8 cm. In LMS patients, overall RR was 42% with 15% LR-RR and 29% D-RR. The 3yr LR-RFS, D-RFS, and DSS were 84%, 65%, and 76%, respectively. When considering high-risk (>5 cm and high-grade, n = 49) LMS patients, the overall RR was 45% with 12% LR-RR and 35% D-RR. 61% received radiation. The 3yr LR-RFS (78vs93%, p = 0.39), D-RFS (53vs63%, p = 0.27), and DSS (67vs91%, p = 0.17) were similar in those who did and did not receive radiation. High-risk, non-LMS patients had a similar overall RR of 42% with 15% LR-RR and 30% D-RR. 60% of non-LMS patients received radiation. There was an improved 3yr LR-RFS (82vs75%, p = 0.030) and DSS (77vs65%,p = 0.007) in non-LMS patients who received radiation. CONCLUSIONS: In our cohort, patients with LMS have a low local recurrence rate (12-15%) and modest distant recurrence rate (29-35%). However, LMS patients had no improvement in local control or long-term outcomes with radiation. The value of radiation in these patients merits further investigation.

Complex Microsurgical Reconstruction After Tumor Resection in the Trunk and Extremities.

Reconstruction of soft tissue defects following tumor ablation procedures in the trunk and extremities can challenge the microsurgeon. The goal is not just to provide adequate soft tissue coverage but also to restore form and function and minimize donor site morbidity. Although the principles of the reconstructive ladder still apply in the trunk and extremities, free tissue transfer is used in many cases to optimally restore form and function. Microsurgery has changed the practice in soft tissue tumors, and amputation is less frequently necessary.

A reconstructive algorithm of oncologic defects of the upper trunk and shoulder girdle: Factors predicting complexity and outcomes.

BACKGROUND: Locally advanced malignancies of the upper torso and shoulder girdle (UT-SG) necessitate extensive resection and complex reconstruction. Due to the infrequent nature of these operations, a global reconstructive algorithm has not been defined. METHODS: A retrospective review of all patients who received reconstructive surgery following malignant tumor extirpation in the UT-SG from 2008 to 2018 at the University of Texas MD Anderson Cancer Center. Factors predicting the need for flap reconstruction and risk for postoperative complications were evaluated. RESULTS: In total, 252 procedures met inclusion criteria. The most common pathology was sarcoma (76%) and 52% were primary tumors. The median defect area was 112 cm2 (range 4-1350 cm2 ). Reconstructive techniques included pedicled flaps (46%), local tissue rearrangement (38%), and free flaps (16%). On univariate analysis, the probability of needing a free flap increased 39% when the defect size increased by 100 cm2 . The strongest independent predictors of requiring a free flap were major vessel exposure (adjusted odds ratio [OR] = 4.92, 95% confidence interval [CI], 1.36-17.84, P = .015) and major peripheral nerve exposure (adjusted OR = 3.2, 95% CI, 1.1-9.2, P = .031). CONCLUSION: Despite the aggressive nature of their malignancies, patients requiring an UT-SG resection demonstrate high survival rates and therefore demand a durable reconstruction. Exposed critical structures and defect size were predictive of free tissue transfer.

Trends in the Use of Adjuvant Chemotherapy for High-Grade Truncal and Extremity Soft Tissue Sarcomas.

BACKGROUND: In the randomized controlled trial (RCT) EORTC 62931, adjuvant chemotherapy failed to show improvement in relapse-free survival (RFS) or overall survival (OS) for patients with resected high-grade soft tissue sarcoma (STS). We evaluated whether the negative results of this 2012 RCT have influenced multidisciplinary treatment patterns for patients with high-grade STS undergoing resection at seven academic referral centers. METHODS: The U.S. Sarcoma Collaborative database was queried to identify patients who underwent curative-intent resection of primary high-grade truncal or extremity STS from 2000 to 2016. Patients with recurrent tumors, metastatic disease, and those receiving neoadjuvant chemotherapy were excluded. Patients were divided by treatment era into early (2000-2011, pre-European Organisation for Research and Treatment of Cancer [EORTC] trial) and late (2012-2016, post-EORTC trial) cohorts for analysis. Rates of adjuvant chemotherapy and clinicopathologic variables were compared between the two cohorts. Univariate and multivariate regression analyses were used to determine factors associated with OS and RFS. RESULTS: 949 patients who met inclusion criteria were identified, with 730 patients in the early cohort and 219 in the late cohort. Adjuvant chemotherapy rates were similar between the early and late cohorts (15.6% versus 14.6%; P = 0.73). Patients within the early and late cohorts demonstrated similar median OS (128 months versus median not reached, P = 0.84) and RFS (107 months versus median not reached, P = 0.94). Receipt of adjuvant chemotherapy was associated with larger tumor size (13.6 versus 8.9 cm, P < 0.001), younger age (53.3 versus 63.7 years, P < 0.001), and receipt of adjuvant radiation (P < 0.001). On multivariate regression analysis, risk factors associated with decreased OS were increasing American Society of Anesthesiologists class (P = 0.02), increasing tumor size (P < 0.001), and margin-positive resection (P = 0.01). Adjuvant chemotherapy was not associated with OS (P = 0.88). Risk factors associated with decreased RFS included increasing tumor size (P < 0.001) and margin-positive resection (P = 0.03); adjuvant chemotherapy was not associated with RFS (P = 0.23). CONCLUSIONS: Rates of adjuvant chemotherapy for resected high-grade truncal or extremity STS have not decreased over time within the U.S. Sarcoma Collaborative, despite RCT data suggesting a lack of efficacy. In this retrospective multi-institutional analysis, adjuvant chemotherapy was not associated with RFS or OS on multivariate analysis, consistent with the results from EORTC 62931. Rates of adjuvant chemotherapy for high-grade STS were low in both cohorts but may be influenced more by selection bias based on clinicopathologic variables such as tumor size, margin status, and patient age than by prospective, randomized data.

The Prognostic Value of Lymphovascular Invasion in Truncal and Extremity Soft Tissue Sarcomas: An Analysis from the National Cancer Database.

OBJECTIVE: The aim of this study was to determine the association between lymphovascular invasion (LVI) and overall survival (OS) in truncal/extremity soft tissue sarcomas (STS). METHODS: The National Cancer Database (NCDB) was queried for all patients, ages 18-85 years, who underwent resection of primary, truncal/extremity STS between 2010 and 2012, and had LVI data. The primary endpoint was OS. RESULTS: Among 6169 patients identified, the most common histology groups were (1) liposarcoma (LPS, 24%), (2) undifferentiated pleiomorphic sarcoma (UPS, 19%), and (3) leiomyosarcoma (LMS, 15%); 449 patients (7%) were LVI-positive. There were no differences in demographics or comorbidities between the LVI groups. Compared with LVI-negative patients, LVI-positive patients were more likely to have larger (> 5 cm: 80% vs. 66%), deep (80% vs. 68%), and high-grade tumors (82% vs. 57%). They were also more likely to have positive margins (27% vs. 17%), nodal (16% vs. 2%) and metastatic disease (21% vs. 4%), and receive chemotherapy (37% vs. 18%; all p < 0.001). LVI was associated with worse median OS (39 months vs. MNR; p < 0.001), which persisted on stratum-specific analyses for all tumor grades, size categories, and stages I-III, but not stage IV. On multivariable Cox regression, LVI was associated with worse OS (hazard ratio [HR] 1.84, 95% confidence interval [CI] 1.39-2.44), while accounting for other significant prognostic factors. Among non-metastatic, curative-intent resections (n = 5696), LVI was still associated with worse OS (HR 1.79, 95% CI 1.28-2.49). CONCLUSIONS: LVI appears to be an important adverse pathologic factor in truncal and extremity STS. Even when taking into account other established prognostic factors, LVI was predictive of worse OS. Knowledge of LVI status may help to better risk-stratify patients and guide management strategies, and should be considered in future prognostic classification schemes and nomograms.

2-cm versus 4-cm surgical excision margins for primary cutaneous melanoma thicker than 2 mm: long-term follow-up of a multicentre, randomised trial.

BACKGROUND: The optimal surgical excision margins are uncertain for patients with thick (>2 mm) localised cutaneous melanomas. In our previous report of this multicentre, randomised controlled trial, with a median follow-up of 6·7 years, we showed that a narrow excision margin (2 cm vs 4 cm) did not affect melanoma-specific nor overall survival. Here, we present extended follow-up of this cohort. METHODS: In this open-label, multicentre randomised controlled trial, we recruited patients from 53 hospitals in Sweden, Denmark, Estonia, and Norway. We enrolled clinically staged patients aged 75 years or younger diagnosed with localised cutaneous melanoma thicker than 2 mm, and with primary site on the trunk or upper or lower extremities. Patients were randomly allocated (1:1) to treatment either with a 2-cm or a 4-cm excision margin. A physician enrolled the patients after histological confirmation of a cutaneous melanoma thicker than 2 mm. Some patients were enrolled by a physician acting as responsible for clinical care and as a trial investigator (follow-up, data collection, and manuscript writing). In other cases physicians not involved in running the trial enrolled patients. Randomisation was done by telephone call to a randomisation office, by sealed envelope, or by computer generated lists using permuted blocks. Patients were stratified according to geographical region. No part of the trial was masked. The primary outcome in this extended follow-up study was overall survival and the co-primary outcome was melanoma-specific survival. All analyses were done on an intention-to-treat basis. The study is registered with ClinicalTrials.gov, number NCT03638492. FINDINGS: Between Jan 22, 1992, and May 19, 2004, 936 clinically staged patients were recruited and randomly assigned to a 4-cm excision margin (n=465) or a 2-cm excision margin (n=471). At a median overall follow-up of 19·6 years (235 months, IQR 200-260), 621 deaths were reported-304 (49%) in the 2-cm group and 317 (51%) in the 4-cm group (unadjusted HR 0·98, 95% CI 0·83-1·14; p=0·75). 397 deaths were attributed to cutaneous melanoma-192 (48%) in the 2-cm excision margin group and 205 (52%) in the 4-cm excision margin group (unadjusted HR 0·95, 95% CI 0·78-1·16, p=0·61). INTERPRETATION: A 2-cm excision margin was safe for patients with thick (>2 mm) localised cutaneous melanoma at a follow-up of median 19·6 years. These findings support the use of 2-cm excision margins in current clinical practice. FUNDING: The Swedish Cancer Society, Stockholm Cancer Society, the Swedish Society for Medical Research, Radiumhemmet Research funds, Stockholm County Council, Wallström funds.

Development of mobile intraoperative computed tomography imaging system and assessment of its performance in a brain and body phantom study.

BACKGROUND: Intraoperative computed tomography (iCT) system has been developed focusing on combining the advanced imaging techniques for the best imaging modality. However, the use of iCT system in the operating rooms is limited due to the lack of flexible mobility. OBJECTIVE: This study aims to develop a mobile iCT imaging system and assess its imaging performance in a phantom study. METHODS: The mobile iCT system with mecanum omni-directional wheels has three major components namely, a rotating gantry, a slip-ring and a stationary gantry. Performance of mecanum iCT system was evaluated using the indices of signal-to-noise (SNR), contrast-to noise (CNR), and spatial resolution (MTF). Anatomical landmarks on phantom images were assessed using a 5-point scale (5 = definitely seen; 4 = probably seen; 3 = equivocal; 2 = probably not seen; and 1 = definitely not seen). RESULTS: The mecanum iCT system can be conveniently used for a whole-body scan under intraoperative conditions even in narrow operating rooms due to a smaller turning radius. The image quality of the mecanum iCT system was found to be acceptable for clinical applications (with SNR = 162.72, CNR = 134.29 and MTF = 694 µm). The diagnostic scores on the phantom images were 'definitely seen' value. CONCLUSIONS: The proposed mecanum iCT system achieved the improved flexible mobility and has potential to better serve as a useful imaging tool in the clinical intraoperative setting.

The impact of unplanned excisions of truncal/extremity soft tissue sarcomas: A multi-institutional propensity score analysis from the US Sarcoma Collaborative.

OBJECTIVE: Our aim was to compare outcomes in patients who underwent unplanned excisions (UE) of soft-tissue sarcomas (STS) against patients with planned excisions (PE). METHODS: The retrospective 7-institution US Sarcoma Collaborative database was used. Patients with curative-intent resection of truncal/extremity STS between 2000 and 2016 were included. Propensity score weighting analysis (PSWA) was performed. Endpoints were locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-specific survival (DSS). RESULTS: One thousand five hundred and ninety-six patients were included. Eighty-two percent (n = 1315) underwent PE and 18% (n = 281) underwent UE. Compared with PE, patients with UE were younger with smaller tumors with similar tumor grade. Unmatched analysis revealed PE was associated with worse DMFS (hazard ratio [HR] 1.95, P = .009) and DSS (HR 1.78, P = .039), but not LRFS compared with UE. On PSWA, UE had earlier LRFS (3-year LRFS: 80.5% vs 89.8%, P = .039), but not DMFS or DSS. By grade, patients with high-grade tumors and UE had worse LRFS (1-year LRFS: 90% vs 94%, P = .015), but similar DMFS and DSS compared with PE. In low-grade patients, UE and PE had similar LRFS, DMFS, or DSS. CONCLUSIONS: UE of STS is not associated with worse prognosis compared to PE, though UE is associated with earlier locoregional recurrence in patients with high-grade tumors. Multimodality therapy is needed to achieve improved outcomes in these patients.