Component Separation Procedure Research Articles

Impact of 2023 Ventral Hernia Repair CPT Code Changes on Work Relative Value Units in a Tertiary Hernia Referral Center.

CPT codes for ventral hernia repair (VHR) changed in January 2023 to address the heterogeneity of procedures with a concomitant shift from a 90-day to a 0-day global period. This study reviews a tertiary referral center's experience with hernia coding comparing the work relative value units (wRVUs) generated for ventral hernia repair pre-2023 compared to post-2023. CPT codes were analyzed for patients undergoing open or laparoscopic VHR before updates to the CPT hernia codes (January 2022-September 2022) and following CPT change (January 2023-September 2023). Work RVU values were assigned based on nationally published values. CPT codes in 2022, CPT codes in 2023, 8 inpatient E&M codes, and 5 outpatient E&M codes were evaluated. 299 patients underwent VHR, 143 in 2022 and 156 in 2023. Average procedural VHR wRVUs increased from 9.6 in 2022 to 11.6 in 2023 (p<0.001). Procedures involving myofascial advancement flaps/component separation techniques (53.8% vs. 48.7%, p = 0.419) and wRVUs for the component separation procedures were similar between 2022 and 2023, respectively 17.7 vs 16.1 (p=0.419)]. The wRVUs associated with adjunctive procedures (mesh removal/placement) decreased from 3.3 to 0.6 (p<0.001) in the post-2023 era. Postoperative E&M wRVUs increased in 2023 for postoperative inpatient (0.48) and postoperative outpatient (0.39) services, compared to 0 wRVUs in 2022. Overall, the total management including follow-up clinic visit adjusted wRVUs for hernia repair was similar between 2022 and 2023, respectively 30.7 vs 29.2 (p=0.409). Procedural wRVUs for anterior abdominal hernia repair increased from 2022 to 2023 (p<0.001) at a tertiary referral medical center. However, total wRVUs, including the operation and postoperative visits, remained unchanged.

Surgeon volumes: preserving appropriate surgical outcomes in higher-risk patient populations undergoing abdominal wall reconstruction.

It is increasingly recognized that complex abdominal wall reconstruction (cAWR) necessitates specialized training. No studies have been conducted to assess whether a volume-outcomes relationship is present in cAWR. We sought to determine if outcomes for patients undergoing cAWR varied based on surgeon volume among participants in the Abdominal Core Health Quality Collaborative (ACHQC). All patients with ventral hernias undergoing elective cAWR with component separation (lateral component release) were selected from ACHQC database. Surgeons were ranked based on annual number of cAWR procedures performed and then grouped in tertiles. Patient characteristics, hernia risk factors, operative details, and 30-days outcomes were evaluated. A total of 9206 patients were identified, of which 310 (3.4%), 723 (7.9%) and 8173 (88.7%) cAWRs were performed by low (105 surgeons), medium (49) and high-volume (66) surgeons, respectively. Patients operated upon by high-volume surgeons tended to have more comorbidities and higher ASA class (72.5% of class ≥ III, vs 53.5%). Hernia characteristics demonstrated that high-volume surgeons more commonly operated on patients presenting with recurrent hernias (50.2% vs 42%), wider hernias (13.5cm vs 10.5cm), associated ostomies (13% vs 3.6%), and prior of surgical site infections (32% vs 26%, P = 0.035). High-volume surgeons more commonly performed posterior component separation procedures (92% vs 84%), utilized permanent mesh (92% vs 88%), and placed mesh in sublay position. In spite of operating on more advanced hernias, high-volume surgeons achieved comparable rates (all P > 0.4) of 30-day surgical site infections (SSI: 6.9% vs 7.1%) and surgical site occurrences requiring procedural intervention (SSO-PI: 8.9% vs 10%). High-volume surgeons maintain comparable outcomes following cAWR despite performing operations on patients with more comorbidities and advanced hernia disease. These findings should be integrated into the debates related to regionalizing abdominal wall reconstruction procedures among high-volume surgeons.

The outcomes of open anterior component separation versus posterior component separation with transversus abdominis release for complex incisional hernias: a systematic review and meta-analysis.

The main objective was to assess the prevalence of hernia recurrence, wound complications (surgical site infections [SSI], seroma and hematoma) and mortality after anterior component separation (ACS) and posterior component separation via transversus abdominis muscle release (PCSTAR) in patients with complex incisional hernias. The so-called complex IH is a serious medical and societal challenge due to its direct and indirect costs; it is also hampered by the use of different surgical techniques, different type of meshes, and different results heterogeneously reported and interpreted. According to actual data, the best approach seems to be a mesh reinforcement component separation procedure augmented or not with an adjuvant technique (preoperative progressive pneumoperitoneum and/or Botulin toxin type A infiltration). A systematic search of four databases (MEDLINE, PubMed, Web of Science, and Google Scholars) was conducted to identify studies reporting on outcomes of component separation techniques and which were published before December 2021. A systematic review and a meta-analysis of postoperative outcomes were performed. Nineteen studies including 3412 patients (1709 with ACS and 1703 with PCSTAR) were selected. Pooled hernia recurrence rate after a minimum 1-year follow-up was evaluated at 5.15% (odds ratio [OR] 0.68; 95% confidence interval [CI] 0.5-0.9; p = 0.0175). Pooled surgical site infection rate was 10.6% (OR 1.32; 95% CI 1.06-1.65; p = 0.0119). Seroma and hematoma were estimated at 9.75% (OR 1.93; 95% CI 1.52-2.44; p = 0.0001) and 3.83% (OR 1.81; 95% CI 1.26-2.61; p = 0.0012), respectively. ACS was associated with increased wound morbidity, seroma and hematoma. PCSTAR displayed higher recurrence rate (4.27% vs 6.11%). PCSTAR was superior to ACS in terms of wound morbidity, surgical site infections, seroma and hematoma incidence. The procedure should be further evaluated in comparative head-to-head randomized controlled trials.

Current practices in complex abdominal wall reconstruction in the Americas: need for national guidelines?

Component separation (CS) procedures have become an important part of surgeons' armamentarium. However, the exact criteria for training, procedure/mesh choice, as well as patient selection for CS remains undefined. Herein we aimed to identify trends in CS utilization between various cohorts of practicing surgeons. Members of the Americas Hernia Society were queried using an online survey. Responders were stratified according to their experience, practice profile (private vs academic, general vs hernia surgery), and volume (low (< 10/year) vs high) of CS procedures. We used Chi-squared tests to evaluate significant associations between surgeon characteristics and outcomes. 275 responses with overwhelming male preponderance (88%) were collected. The two most common self-identifiers were "general" (66%) and "hernia" (28%) surgeon. PCS was the most commonly (67%) used type of CS; endoscopic ACS was least common (3%). Low-volume surgeons were more likely to utilize the ACS (p < 0.05). Only 7% of respondents learned PCS during their residency, as compared to 36% that use ACS. 65% felt 0-10 cases was sufficient to become proficient in their preferred technique. 10cm-wide defect was the most common indication for CS; 23% used it for 5-8cm defects. Self-identified "hernia" and high-volume surgeons were more likely to use synthetic mesh in the setting of previous wound infections and/or contaminated field (p < 0.05). More general/low-volume surgeons use biologic mesh. Contraindications to elective CS varied widely in the cohort, and 9.5% would repair poorly optimized patients electively. Severe morbid obesity was the most feared comorbidity to preclude CS. The use of CS varies widely between surgeons. In this cohort, we discovered that PCS was the most commonly used technique, especially by hernia/high-volume surgeons. There are differences in mesh utilization between high-volume and low-volume surgeons, specifically in contaminated fields. Despite its prevalence, CS training, indications/contraindications, and patient selection must be better defined.

Rule-Based EEG Classifier Utilizing Local Entropy of Time–Frequency Distributions

Electroencephalogram (EEG) signals are known to contain signatures of stimuli that induce brain activities. However, detecting these signatures to classify captured EEG waveforms is one of the most challenging tasks of EEG analysis. This paper proposes a novel time–frequency-based method for EEG analysis and characterization implemented in a computer-aided decision-support system that can be used to assist medical experts in interpreting EEG patterns. The computerized method utilizes EEG spectral non-stationarity, which is clearly revealed in the time–frequency distributions (TFDs) of multicomponent signals. The proposed algorithm, which is based on the modification of the Rényi entropy, called local or short-term Rényi entropy (STRE), was upgraded with a blind component separation procedure and instantaneous frequency (IF) estimation. The method was applied to EEGs of both forward and backward movements of the left and right hands, as well as to EEGs of imagined hand movements, which were captured by a 19-channel EEG recording system. The obtained results show that in a given virtual instrument, the proposed methods efficiently distinguish between real and imagined limb movements by considering their signatures in terms of the dominant EEG component’s IFs at the specified subset of EEG channels (namely, F3, F4, F7, F8, T3, and T4). Furthermore, computing the number of EEG signal components, their extraction, and IF estimation provide important information that shows potential to enhance existing clinical diagnostic techniques for detecting the intensity, location, and type of brain function abnormalities in patients with neurological motor control disorders.

Evaluation of the use of component separation in elderly patients: results of a large cohort study with 30-day follow-up.

The incidence of massive ventral hernias among the elderly will increase as the population ages. Advanced age is often viewed as a contraindication to elective hernia repair. A relationship between age and complications of component separation procedures for ventral hernias is not well established. This study evaluated the effect of age on the peri-operative safety of AWR. The 2005-2013 ACS-NSQIP participant use data were reviewed to compare surgical site infection (SSI), overall morbidity, and serious morbidity in non-emergent component separation procedures among all age groups. All patients were stratified into four age quartiles and evaluated. Baseline characteristics included age, body mass index (BMI) and ASA 3 or 4 criteria. Statistical analysis was performed using SPSS. Odds ratios (OR) and 95% confidence intervals were reported as appropriate. 4485 patients were identified. Majority of the cases were clean (76.8%). Patients were divided into the following quartiles based on age. The older quartile had a mean age of 72.7 ± 4.87years. There were baseline differences in BMI and chronic comorbidity severity (measured by incidence of ASA score of 3 or 4) between the age groups, with the oldest group having lower BMI but higher rate of ASA 3 or 4 (p < 0.0001 for both). The rate of postoperative SSI was significantly different between age quartile groups (ranging from 16.3% from the youngest group to 9.4% for the oldest group, p < 0.0001). After adjusting for other baseline differences, advanced age was independently associated with lower SSI rate (OR 0.55, 95% CI 0.41-0.73). There was no significant difference in overall morbidity (p = 0.277) and serious morbidity (p = 0.131) between groups. AWR is being performed with safety across all age groups. In selected patients of advanced age, AWR can be performed with similar safety profile and low SSI rate.

Quantitative Assessment of Tension Reduction at the Midline Closure During Abdominal Component Separation

Abdominal component separation is used commonly for closure of midline abdominal wounds. The value of each step in reducing tension has not been studied. Our aim was to test whether component separation decreases tension in the midline closure and to quantify the value of each procedural step. Tension required to bring the rectus muscle to midline was measured using tensiometry after subcutaneous dissection (step 1), external oblique muscle release (step 2), separation of the internal and external oblique muscles (step 3), and internal oblique muscle release (step 4). Measurements were taken in the upper, middle, and lower thirds of the abdominal midline. Distance to midline was also measured after each surgical step. Tension (measured as percent change) and distance were analyzed using Student's t-test with significance set at p < 0.05. In 41 hemi-abdominal defects, tension decreased in middle, upper, and lower thirds of the abdomen by 22.5%, 24.3%, and 34.8% after step 1; 33.4%, 31.8%, and 39.8% after step 2; 26.5%, 22.2%, and 27.4% after step 3; and 33.2%, 28.2%, and 23.5% after step 4. Mean distance change was 0.97 cm, 1.97 cm, 2.22 cm, and 2.59 cm after steps 1 to 4, respectively. This study shows through a quantitative measure of tension that all steps of the component separation procedure decrease wound tension to variable degrees, with the release of the external and internal oblique muscles being the more effective steps. An internal oblique release is a useful and simple adjunct to the classical component separation procedure.

Planckintermediate results

The Planck mission, thanks to its large frequency range and all-sky coverage, has a unique potential for systematically detecting the brightest, and rarest, submillimetre sources on the sky, including distant objects in the high-redshift Universe traced by their dust emission. A novel method, based on a component-separation procedure using a combination of Planck and IRAS data, has been applied to select the most luminous cold submm sources with spectral energy distributions peaking between 353 and 857GHz at 5' resolution. A total of 2151 Planck high-z source candidates (the PHZ) have been detected in the cleanest 26% of the sky, with flux density at 545GHz above 500mJy. Embedded in the cosmic infrared background close to the confusion limit, these high-z candidates exhibit colder colours than their surroundings, consistent with redshifts z>2, assuming a dust temperature of 35K and a spectral index of 1.5. First follow-up observations obtained from optical to submm have confirmed that this list consists of two distinct populations. A small fraction (around 3%) of the sources have been identified as strongly gravitationally lensed star-forming galaxies, which are amongst the brightest submm lensed objects (with flux density at 545GHz ranging from 350mJy up to 1Jy) at redshift 2 to 4. However, the vast majority of the PHZ sources appear as overdensities of dusty star-forming galaxies, having colours consistent with z>2, and may be considered as proto-cluster candidates. The PHZ provides an original sample, complementary to the Planck Sunyaev-Zeldovich Catalogue; by extending the population of the virialized massive galaxy clusters to a population of sources at z>1.5, the PHZ may contain the progenitors of today's clusters. Hence the PHZ opens a new window on the study of the early ages of structure formation, and the understanding of the intensively star-forming phase at high-z.

Is There an Association between Component Separation and Venous Thromboembolism? Analysis of the NSQIP.

Background:Patients undergoing incisional/ventral hernia repair are at risk of developing several postoperative complications particularly venous thromboembolism (VTE), which is a major cause of morbidity and mortality. The aim of this study was to assess 30-day postoperative morbidity and mortality of patients undergoing incisional/ventral hernia repair and to determine the association between component separation and VTE.Methods:We reviewed the 2005–2011 American College of Surgeons National Surgical Quality Improvement Program databases to identify patients undergoing incisional/ventral hernia repair. Preoperative variables and postoperative outcomes were compared between a component separation group and a non–component separation group. The χ2 tests and Fisher’s exact test were used for categorical variables and t tests for continuous variables. Logistic regression analysis was performed to determine preoperative predictors for complications in both groups.Results:Thirty-four thousand five hundred forty-one patients were included in our study; 501 patients underwent a component separation procedure. A higher rate of wound complications, minor/major morbidity, mortality, and return to the operating room occurred in the component separation group. However, there was no statistically significant difference in deep vein thrombosis/thrombophlebitis and pulmonary embolism rates between the 2 groups (P = 0.780 and P = 0.591, respectively). Several risk factors were significantly associated with postoperative complications in both groups.Conclusions:Component separation is used for large and complex incisional/ventral hernia repairs to achieve tension-free midline closure. Although component separation hernia repair is associated with higher incidence of wound complication, morbidity, and mortality, perhaps because of the complexity of the defects, it does not seem to be associated with increased VTE rates.

Mapping possible non-Gaussianity in thePlanckmaps

[Abridged.] It is conceivable that no single statistical estimator can be sensitive to all forms and levels of non-Gaussianity that may be present in observed CMB data. In recent works a statistical procedure based upon the calculation of the skewness and kurtosis of the patches of CMB sky-sphere has been proposed and used to find out significant large-angle deviation from Gaussianity in the foreground-reduced WMAP maps. Here we address the question as to how the analysis of Gaussianity of WMAP maps is modified if the foreground-cleaned Planck maps are used, therefore extending and complementing the previous analyses in several regards. We carry out a new analysis of Gaussianity with the available nearly full-sky foreground-cleaned Planck maps. As the foregrounds are cleaned through different component separation procedures, each of the resulting Planck maps is then tested for Gaussianity. We determine quantitatively the effects for Gaussianity of masking the foreground-cleaned Planck maps with the INPMASK, VALMASK, and U73 Planck masks. We show that although the foreground-cleaned Planck maps present significant deviation from Gaussianity of different degrees when the less severe INPMASK and VALMASK are used, they become consistent with Gaussianity as detected by our indicator $S$ when masked with the union U73 mask. A slightly smaller consistency with Gaussianity is found when the $K$ indicator is employed, which seems to be associated with large-angle anomalies reported by the Planck team. Finally, we examine the robustness of the Gaussianity analyses with respect to the noise pixel's as given by the Planck team, and show that no appreciable changes arise when is incorporated into the maps. The results of our analyses provide important information about the suitability of the foreground-cleaned Planck maps as Gaussian reconstructions of the CMB sky.

Power spectrum distortions in CMB map one-dimensional cross-sections depending on the cosmological model

We examine the effect produced by the variation of parameters of the cosmological model on the power spectrum of one-dimensional cross-sections of the cosmic microwave background maps. We also investigate the possibility of determining these parameters in the analysis of one-dimensional data. The features of the component separation procedure, leading to additional restrictions on the accuracy of reconstruction of the original spectrum are discussed. When the low harmonics remain in the map, the power spectrum of a one-dimensional cross-section is poorly sensitive to the variations of a number of cosmological parameters. Still, the analysis of one-dimensional data could be useful in the search and study of anomalous effects.

Repair of recurrent ventral hernias using tissue expansion and porcine acellular dermal matrix

Recurrent ventral hernias are often large and associated with loss of abdominal domain, hindering primary closure. One established intervention for patients with large ventral hernias is the component separation procedure that advances muscle from the lateral abdomen. This technique allows closure without creating tension; however, the relaxing incisions weaken the lateral abdominal wall by altering its natural architecture. We propose an approach to primary midline closure that does not compromise lateral abdominal wall stability and restores the architecture of the abdominal wall while allowing tension-free midline closure. In three patients with recurrent ventral hernias who had failed two or more repair attempts, we used a two-stage reconstruction. Bilateral rectangular tissue expanders placed between the external and internal oblique muscles via subcostal incisions were expanded for 6–8 weeks. Second-stage surgery consisted of expander removal and primary closure of the abdominal defect reinforced by an underlay and overlay of noncross-linked intact porcine-derived acellular dermal matrix (PADM; Strattice™ Reconstructive Tissue Matrix, LifeCell, Branchburg, NJ, USA). Primary closure of ventral hernias measuring 8 × 8, 12 × 8, and 8 × 6 cm was achieved with no need for component separation. At follow-up ranging from 10 to 17 months, all patients had structurally intact abdomens with no hernia recurrence and no abdominal wall weakness. All patients have resumed normal daily activities, including returning to work. Expansion of the external and internal oblique muscles combined with an underlay and overlay of noncross-linked intact PADM allows strong and reliable primary closure of recurrent ventral hernias without the need for component separation. Level of evidence: Level V, therapeutic study

The platelet storage lesion.

D URING THE PAST 2 decades, the demand for platelet concentrates (PC) has been steadily increasing because of more intense treatment schedules as well as widening indications for the use of chemotherapy. This has. placed considerable pressure on the logistics of supply. The emphasis on reducing donor exposure, caused by the possibility of transfusion associated alloimmunisation and leucocyte borne infection, t has led to an increase in the use of apheresis and leucoreduced PC. In re@onse to these requirements, measures have been taken that are aimed at maximum resource use, for example: by splitting a high platelet yield unit, collected by a cell separator, into two therapeutic doses (-->240 • 109/dose); development of new containers and storage media to permit prolonging the length of storage period; and the development of new generation of leukocyte filters as welLas modem apheresis procedures to achieve high purity leukoreducedproducts (~1 • 106/unit). In parallel to the above development, the bottom and top (BAT) bag system, 2 combined with semiautomated blood component separation procedures, have been used to optimize platelet recovery from whole blood and to standardize the yield. This has enabled the consistent production of PC with an average dose of 300 X 109 platelets/unit and leucocyte content 0.05 X 109/unit from a pool of four ABO compatible buffy coats. Storage in synthetic media has been proposed 3 with the practical advantages of reducing the rapid accumulation of lactate and the removal of some plasma components, cell-released enzymes, and soluble antigens including HLA; therefore improving the viability of platelets as well as reducing potential transfusion reactionsJ -6 Despite these continual process improvements and major advances in establishing optimized storage conditions, the platelet storage lesion (PSL) as manifested by the loss. of function and changes in morphology associated with vacuolisation and plate-