Harvesting, Embedding, and Culturing Dorsal Root Ganglia in Multi-compartment Devices to Study Peripheral Neuronal Features.

The most common peripheral neuronal feature of pain is a lowered stimulation threshold or hypersensitivity of terminal nerves from the dorsal root ganglia (DRG). One proposed cause of this hypersensitivity is associated with the interaction between immune cells in the peripheral tissue and neurons. In vitro models have provided foundational knowledge in understanding how these mechanisms result in nociceptor hypersensitivity. However, in vitro models face the challenge of translating efficacy to humans. To address this challenge, a physiologically and anatomically relevant in vitro model has been developed for the culture of intact dorsal root ganglia (DRGs) in three isolated compartments in a 48-well plate. Primary DRGs are harvested from adult Sprague Dawley rats after humane euthanasia. Excess nerve roots are trimmed, and the DRG is cut into appropriate sizes for culture. DRGs are then grown in natural hydrogels, enabling robust growth in all compartments. This multi-compartment system offers anatomically relevant isolation of the DRG cell bodies from neurites, physiologically relevant cell types, and mechanical properties to study the interactions between neural and immune cells. Thus, this culture platform provides a valuable tool for investigating treatment isolation strategies, ultimately leading to an improved screening approach for predicting pain.

Anterior Iliac Crest Bone Graft Harvest Using Acetabular Reamers.

VIDEO AVAILABLE AT: https://ota.org/education/ota-online-resources/video-library-procedures-techniques/anterior-iliac-crest-bone-0.

Efficacy of lengthening right renal veins using accompanying gonadal veins in living donor kidney transplantation.

BACKGROUND: Short harvested right renal veins (RV) are quite common in living donor kidney transplantation (KT). This technical difficulty might interfere implanting and increase warm ischemic time. Several techniques to overcome this problem have been applied, including iliac vein transposition, inverted transplant, synthetic graft, saphenous vein… Application of accompanying gonadal vein (GV), which is easily approachable and less time-consuming, has been recently published. This study aims to evaluate its effectiveness and safety. METHODS: Retrospective study on KT using the gonadal vein to lengthen the short right renal vein at Viet Duc University Hospital from April 2019 to April 2022. The following data were gathered: baseline characteristics, vascular imaging in CT scan/after nephrectomy and after reconstruction (mm), reconstruction and surgical time, hospitalization days. The outcomes were determined by kidney function after transplantation (plasma creatinine, creatinine clearance) and related complications. RESULTS: Twenty-five cases with procured right kidney with short RV from the living donor which were reconstructed and lengthened by the accompanying GV were collected. The additional length of RV was 15.9 ± 2.4 mm. Average cold ischemic time, venoplasty time, warm ischemic time were 60.4 ± 8.2, 21.2 ± 5.3, and 38.1 ± 5.6 min, respectively. The average hospital stay was 15.3 ± 3.2 days. Average follow-up time was 31 ± 5.2 months, creatinine clearance was around 60 ml/min after 1 year, no vascular or urologic complications was observed. CONCLUSION: Accompanying GV from a living donor to lengthen short right RV in KT is a feasible, safe, and effective technique.

Safety and graft outcome of right retroperitoneal laparoscopic donor nephrectomy for living donor kidney transplantation: A comparison with left retroperitoneal laparoscopic donor nephrectomy.

INTRODUCTION: The left kidney is often preferred for living donor kidney transplantation because of its anatomical advantages. However, the right kidney may be procured due to donor conditions. Few studies have assessed the safety and graft outcome of right retroperitoneal laparoscopic donor nephrectomy (RDN). This study aimed to compare the outcomes between right and left RDN with respect to donor outcome and the graft function of recipients. METHODS: This retrospective study included 230 consecutive living donor kidney transplants performed at our institution between May 2019 and March 2023. We reviewed the outcomes of kidney transplant in the right and left kidneys after RDN. RESULTS: A total of 230 living donor kidney transplants were performed, with 32 donors receiving right RDN (right RDN group) and 198 donors receiving left RDN (left RDN group). The renal veins and ureters were significantly shorter in the right RDN group than in the left RDN group (both p < .001). Donor operation and warm ischemia time were significantly longer in the right RDN group than in the left RDN group (p = .012 and p < .001, respectively). None of the groups exhibited any cases of delayed graft function owing to donor-related reasons. Perioperative changes in the estimated glomerular filtration rate of recipients and death-censored graft survival were not significantly different between the two groups. CONCLUSIONS: In RDN, the outcomes of right donor nephrectomy were comparable to those of left donor nephrectomy in terms of donor safety and recipient renal function.

Endoscopic Vein Harvesting - How Do We Do It?

The saphenous vein graft (SVG) remains the most used conduit as a second graft in Coronary Artery Bypass Grafting (CABG).1 Traditionally, surgeons harvest SVG with an open approach, making a long incision along the medial part of the leg or thigh. This procedure can potentially result in important complications, such as delayed wound healing, postoperative pain and infection.2 Thus, less invasive techniques for vessel harvesting have grown in popularity. Endoscopic vein harvesting (EVH) is a minimally invasive harvesting procedure, which only requires a short incision, leading to less wound complications and a faster return to normal daily activities. This article intends to describe how we do EVH technique in our centre, from the preparation of the patient to the postoperative period and share some tips and tricks from our experience.

Evaluation of the effect of vascularized fibula graft harvesting on coronal plane alignment and functional outcomes of the lower limb.

Recent studies on fibular osteotomy for varus gonarthrosis and possible subsequent biomechanical changes have attracted increasing attention to the topic. Existing studies have focused mainly on proximal fibular osteotomy with short follow-up periods. The aim of this study was to investigate changes in the alignment of the coronal plane of the ankle and knee joints in patients who underwent vascularized fibula graft harvest (VFGH). The evaluation was based on functional outcomes and radiological measurements.In the comparison between the VFGH side and the contralateral side, no significant differences in the knee inclination (KI) or talar inclination (TI) angle, knee medial clear space (K-MCS) or ankle medial clear space (A-MCS) distance were noted. However, a significant difference in the hip knee (HKA) angle was observed between the operated and nonoperated sides (0.3° ± 1.8° and 1.5° ± 1.9°, respectively [p = 0.019]). Statistically significant differences in both the knee society score (KSS) and the AOFAS scores were found between the ipsilateral donor limb and the contralateral healthy limb. Although the contralateral healthy side had better clinical scores than the VFGH side, the outcomes of the VFGH side were still satisfactory or excellent.

The Use of a Simple Vaginal Speculum to Harvest Quadriceps Tendon Autografts for Anterior Cruciate Ligament Reconstruction and Avoid Any Potential Pitfalls during Harvesting Procedure: Technical note.

This technical note aimed to present a straigthforward method for harvesting quadriceps tendon autografts with the use of a simple vaginal speculum and direct visualisation of a scope. Anterior cruciate ligament reconstruction with quadriceps tendon autografts has gained popularity in recent years, with many harvesting techniques that use different harvesting systems available on the market. These techniques vary from transverse to longitudinal skin incisions and from open to minimally invasive approaches and have a learning curve, as with the majority of surgical procedures. The technique proposed in this technical note is minimally invasive, can be easily reproduced by any surgeon irrespective of their experience, has a short learning curve, requires no additional cost or technical support during the procedure and creates a stable working space that allows for freedom of manipulation of surgical instruments and the arthroscope.

Risk factors for infection at the saphenous vein harvest site after coronary artery bypass grafting surgery: a retrospective cohort study.

INTRODUCTION: Surgical site infection after saphenous vein harvest is common, with reported leg wound infection rates ranging from 2 to 24%. There have been few investigations into sex-related differences in complication rates. Moreover, varied effects of smoking have been reported. The aim of this study was to investigate risk factors such as gender and smoking, associated with surgical site infection after vein graft harvesting in coronary artery bypass grafting surgery. METHODS: We included 2,188 consecutive patients who underwent coronary artery bypass grafting surgery with at least one vein graft at our centre from 2009 to 2018. All patients were followed up postoperatively. Risk factors for leg wound infection requiring antibiotic treatment and surgical revision were analysed using logistic regression analysis. RESULTS: In total, 374 patients (17.1%) received antibiotic treatment and 154 (7.0%) underwent surgical revision for leg wound infection at the harvest site. Female sex, high body mass index, diabetes mellitus, longer operation time, peripheral vascular disease and direct oral anticoagulants were independently associated with any leg wound infection at the harvest site. Among surgically revised patients, female sex and insulin or oral treatment for diabetes mellitus as well as longer operation time were independent risk factors. Smoking was not associated with leg wound infection. CONCLUSION: Female sex is associated with increased risk of leg wound infection. The underlying mechanism is unknown. In the current population, previous or current smoking was not associated with an increased risk of leg wound infection.

The Unified Brain-Based Determination of Death Conceptually Justifies Death Determination in DCDD and NRP Protocols.

Organ donation after the circulatory determination of death requires the permanent cessation of circulation while organ donation after the brain determination of death requires the irreversible cessation of brain functions. The unified brain-based determination of death connects the brain and circulatory death criteria for circulatory death determination in organ donation as follows: permanent cessation of systemic circulation causes permanent cessation of brain circulation which causes permanent cessation of brain perfusion which causes permanent cessation of brain function. The relevant circulation that must cease in circulatory death determination is that to the brain. Eliminating brain circulation from the donor ECMO organ perfusion circuit in thoracoabdominal NRP protocols satisfies the unified brain-based determination of death but only if the complete cessation of brain circulation can be proved. Despite its medical and physiologic rationale, the unified brain-based determination of death remains inconsistent with the Uniform Determination of Death Act.

Mid-term outcomes of endoscopic vein harvesting in coronary artery bypass grafting: a retrospective cohort study.

OBJECTIVES: Endoscopic vein harvesting (EVH) is an alternative technique to obtain the saphenous vein for coronary artery bypass grafting (CABG) surgery. We aimed to evaluate the early and mid-term outcomes of patients with EVH in CABG. METHODS: This cohort study included consecutive isolated CABG patients in Nanjing First Hospital from July 2020 to December 2022 using propensity score matching methods. Patients were classified to EVH group and open vein harvesting (OVH) group according to the vein harvesting methods. The primary outcome was the all-cause death, and the secondary outcomes were major adverse cardiovascular events (MACEs) including cardiovascular death, heart failure, myocardial infarction and revascularization and asymptomatic survival in the follow-up. RESULTS: Totally 1247 patients were included in the study with 849 in OVH group and 398 in EVH group. Patients with EVH were more female, diabetes, higher body mass index, more multi-vessel and left main diseases. 308 pairs were formed after the matching. There was no significant difference in the rates of in-hospital death (EVH vs. OVH, 2.3% vs. 1.3%, P = 0.543). During the 3 years follow-up, EVH grafts were considered not inferior to OVH grafts, no differences were found in all-cause death [8.5% vs. 5.0%, hazard ratio (HR) 1.565, 95% confidence interval (CI): 0.77-3.17, P = 0.21], MACEs (8.1% vs. 7.1%, HR 1.165, 95CI: 0.51-2.69, P = 0.71) and asymptomatic survival (66.7% vs. 72.5%, HR 1.117, 95%CI: 0.65-1.92, P = 0.68). CONCLUSIONS: EVH grafts were considered comparable to OVH grafts in patients following CABG in the 3 years follow-up.

Can CT or MRI volumetry substitute scintigraphy in living kidney donor evaluation? A systematic review.

BACKGROUND: Current potential living kidney donor's assessment includes functional and anatomical evaluation. Scintigraphy is recommended in some cases and some centers include this test in the donor's protocol. Recent studies advocate for the avoidance of this test as CT or MRI volumetry showed to accurately assess donor's renal function. OBJECTIVE: To summarize scientific evidence on image tests for pre-donation and/or post-nephrectomy renal function evaluation. EVIDENCE ACQUISITION: This review followed the guidelines set by the European Association of Urology and adhered to PRISMA 2020 recommendations. The protocol was registered in PROSPERO on 10th December 2022 (ID: CRD42022379273). EVIDENCE SYNTHESIS: Twenty-one studies met the inclusion criteria after thorough screening and eligibility assessment. According to QUADAS-2, patient selection and flow/timing domains showed a predominant low risk of bias. The correlation between split renal function (SRF) using CT and scintigraphy varied from weak (r = 0.21) to remarkably strong (r = 0.949). Bland-Altman agreement demonstrated moderate to excellent results, with mean differences ranging from -0.06% to 1.76%. The correlation between split renal volume (CT) and estimated glomerular filtration rate (eGFR) at 6 months or 1 year after nephrectomy showed a moderate correlation, with coefficients ranging from 0.708 to 0.83. The correlation between SRF (MRI) and renal scintigraphy reported a moderate correlation, with correlation coefficients of 0.58 and 0.84. MRI and scintigraphy displayed a good agreement, with a 66% agreement observed and mean differences of ± 0.3%. CONCLUSIONS: Despite study heterogeneity, MRI or CT-based renal volumetry appears promising compared to scintigraphy, with favorable correlations and agreement.

Skeletonized Versus Pedicled Harvesting of the Internal Thoracic Artery and Long-Term Clinical Outcomes in Coronary Artery Bypass Surgery.

BACKGROUND: The internal thoracic artery (ITA) is the most important conduit for coronary artery bypass grafting. Recent evidence suggests that skeletonized ITA harvesting yields long-term outcomes inferior to those of pedicled harvesting. The aim was to investigate the impact of the ITA harvesting method on 10-year mortality and major adverse cardiovascular events. METHODS AND RESULTS: In this observational cohort study, we identified all patients from the SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) register who underwent isolated coronary artery bypass grafting using at least 1 ITA at Karolinska University Hospital from 2012 to 2021. The main outcome was all-cause mortality, and the secondary outcomes were a combination of myocardial infarction, repeat revascularization, heart failure, and stroke. Outcomes were ascertained using national health data registers and compared between the skeletonized and pedicled groups using weighted flexible parametric survival models. Among 3267 patients, 1657 (51%) underwent pedicled ITA harvesting and 1610 (49%) underwent skeletonized ITA harvesting. The patients' mean age was 66 years, and 15% were women. The weighted all-cause mortality incidence rate in the pedicled versus skeletonized ITA group was 2.6% (95CI, 2.2%-3.0%) versus 2.6% (95% CI, 2.2%-3.1%), respectively (hazard ratio (HR), 1.01 [95% CI, 0.81-1.27]). The weighted major adverse cardiovascular events incidence rate was 7.8% (95% CI, 7.1%-8.6%) versus 7.5% (95% CI, 6.7%-8.4%), respectively (HR, 0.94 [95% CI, 0.82-1.08]). CONCLUSIONS: We found no significant differences in all-cause mortality or major adverse cardiovascular events rates between the 2 ITA harvesting methods.

Biological attributes required for epidermal regeneration: Evaluation of the next-generation autologous cell harvesting device.

Early wound intervention and closure is critical for reducing infection and improving aesthetic and functional outcomes for patients with acute burn wounds and nonthermal full-thickness skin defects. Treatment of partial-thickness burns or full-thickness injuries with autologous skin cell suspension (ASCS) achieves robust wound closure while limiting the amount of donor skin compared with standard autografting. A Next Generation Autologous Cell Harvesting Device (NG-ACHD) was developed to standardize the preparation process for ASCS to ensure biological attributes are obtained known to correlate with well-established safety and performance data. This study compared ASCS prepared using the NG-ACHD and ACHD following the manufacturer's guidance, evaluating cellular yields, viability, apoptotic activity, aggregates, phenotypes and functional capacity. Non-inferiority was established for all biological attributes tested and comparable healing trajectories were demonstrated using an in vitro skin regeneration model. In addition to standardization, the NG-ACHD also provides workflow efficiencies with the potential to decrease training requirements and increase the ease of incorporation and utilization of ASCS in clinical practice.

Topographical and histological analysis of keratinized mucosal grafts removal techniques an ex-vivo study in porcine mandibles.

The aim of this study was to assess the surface and tissue quality of keratinized mucosa grafts (KMG) obtained using the conventional scalpel and mucotome techniques. This was an experimental in vitro/ex vivo study involving six porcine hemi-mandibles. Specimens were harvested using both the mucotome and conventional scalpel techniques, with randomization determining the choice of technique for tissue removal. The specimens were prepared following predefined laboratory protocols and subsequently subjected to optical microscopy for evaluating epithelial and connective tissue and scanning electron microscopy for topographical and 3D profilometry analysis. Tissues harvested using the mucotome exhibited a linear base and uniform thickness, along with the presence of submucosa and fibrous connective tissue, all of which are ideal for graft success. Differences in the surface characteristics of specimens obtained through the two techniques were observed during a comparative analysis of images obtained through both microscopy types. KMG obtained using the mucotome technique displayed greater uniformity and reduced undesirable cell presence compared to the scalpel technique, thereby enhancing the likelihood of success in soft tissue graft surgical procedures. This study provides valuable insights to oral healthcare professionals and may contribute to future research aimed at achieving more successful surgeries, shorter postoperative recovery times, reduced discomfort, and an overall more positive patient experience.

Double lung en bloc procurement and back table separation of lungs.

Donor organ recovery techniques have improved with novel preservation solutions, implementation of advanced preservation systems and machine perfusion. However, surgical techniques for organ procurement have not changed. In this video tutorial, we have outlined key steps in double lung en bloc organ recovery, including introduction of pulmonoplegia, pulmonectomy en bloc and separation of the two single-lung blocks.

Robotic-assisted free flap harvesting for diverse soft tissue reconstruction: a PRISMA scoping review of clinical outcomes over the last decade.

Introduction: The aim of our study was to assess the advantages and limitations of robotic technology in diverse reconstructive procedures. METHODS: A scoping review was conducted in Oct'23, on published studies from 2013 to 2023, focussing on robotic-assisted free flap harvesting. Three databases Ovid-MEDLINE, Scopus, and PubMed were searched. Original research studies reporting robotic-assisted free flap harvest were included. Studies on lesion excision, microvascular anastomosis, local flap harvest, roboticassisted flap inset, review articles, abstract-only studies, non-English documents, and animal studies were excluded from this review. RESULTS: Sixteen studies met the inclusion criteria out of a total of 318, searched initially. These studies included a total of 128 patients, who underwent robotic-assisted free flap harvest for the reconstruction of various defects, with 140 free flaps harvested. The most common flaps harvested by robotic technique were deep inferior epigastric artery perforator (DIEP) flap 120 (85.7%), radial forearm free (RFF) flap 11 (7.9%), latissimus dorsii flap 4 (2.9%), rectus abdominus flap 4 (2.9%), and omental flap 1 (0.7%). Breast reconstruction was the major procedure done i.e. 120 (85.7%) followed by head and neck 11 (7.9%) and limb defects 9 (6.4%) reconstruction procedures. The reported clinical outcomes were acceptable in all the studies with a 99% flap success rate and minimal complications. Variability in operating time was observed depending upon surgical steps undertaken with robotic systems. CONCLUSIONS: This scoping review highlights the role of robotic-assisted free flap harvesting in plastic surgery and its potential benefits on clinical outcomes, due to its high precision and minimal invasiveness. However, challenges like cost effectiveness, resource distribution and learning curve are there.

Robotic versus laparoscopic versus open nephrectomy for live kidney donors.

BACKGROUND: Waiting lists for kidney transplantation continue to grow. Live kidney donation significantly reduces waiting times and improves long-term outcomes for recipients. Major disincentives to potential kidney donors are the pain and morbidity associated with surgery. This is an update of a review published in 2011. OBJECTIVES: To assess the benefits and harms of open donor nephrectomy (ODN), laparoscopic donor nephrectomy (LDN), hand-assisted LDN (HALDN) and robotic donor nephrectomy (RDN) as appropriate surgical techniques for live kidney donors. SEARCH METHODS: We contacted the Information Specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 31 March 2024 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing LDN with ODN, HALDN, or RDN were included. DATA COLLECTION AND ANALYSIS: Two review authors independently screened titles and abstracts for eligibility, assessed study quality, and extracted data. We contacted study authors for additional information where necessary. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. MAIN RESULTS: Thirteen studies randomising 1280 live kidney donors to ODN, LDN, HALDN, or RDN were included. All studies were assessed as having a low or unclear risk of bias for selection bias. Five studies had a high risk of bias for blinding. Seven studies randomised 815 live kidney donors to LDN or ODN. LDN was associated with reduced analgesia use (high certainty evidence) and shorter hospital stay, a longer procedure and longer warm ischaemia time (moderate certainty evidence). There were no overall differences in blood loss, perioperative complications, or need for operations (low or very low certainty evidence). Three studies randomised 270 live kidney donors to LDN or HALDN. There were no differences between HALDN and LDN for analgesia requirement, hospital stay (high certainty evidence), duration of procedure (moderate certainty evidence), blood loss, perioperative complications, or reoperations (low certainty evidence). The evidence for warm ischaemia time was very uncertain due to high heterogeneity. One study randomised 50 live kidney donors to retroperitoneal ODN or HALDN and reported less pain and analgesia requirements with ODN. It found decreased blood loss and duration of the procedure with HALDN. No differences were found in perioperative complications, reoperations, hospital stay, or primary warm ischaemia time. One study randomised 45 live kidney donors to LDN or RDN and reported a longer warm ischaemia time with RDN but no differences in analgesia requirement, duration of procedure, blood loss, perioperative complications, reoperations, or hospital stay. One study randomised 100 live kidney donors to two variations of LDN and reported no differences in hospital stay, duration of procedure, conversion rates, primary warm ischaemia times, or complications (not meta-analysed). The conversion rates to ODN were 6/587 (1.02%) in LDN, 1/160 (0.63%) in HALDN, and 0/15 in RDN. Graft outcomes were rarely or selectively reported across the studies. There were no differences between LDN and ODN for early graft loss, delayed graft function, acute rejection, ureteric complications, kidney function or one-year graft loss. In a meta-regression analysis between LDN and ODN, moderate certainty evidence on procedure duration changed significantly in favour of LDN over time (yearly reduction = 7.12 min, 95% CI 2.56 to 11.67; P = 0.0022). Differences in very low certainty evidence on perioperative complications also changed significantly in favour of LDN over time (yearly change in LnRR = 0.107, 95% CI 0.022 to 0.192; P = 0.014). Various different combinations of techniques were used in each study, resulting in heterogeneity among the results. AUTHORS' CONCLUSIONS: LDN is associated with less pain compared to ODN and has comparable pain to HALDN and RDN. HALDN is comparable to LDN in all outcomes except warm ischaemia time, which may be associated with a reduction. One study reported kidneys obtained during RDN had greater warm ischaemia times. Complications and occurrences of perioperative events needing further intervention were equivalent between all methods.

Histological assessment of a novel de-epithelialization method for connective tissue grafts harvested from the palate. An experimental study in cadavers.

OBJECTIVES: This study aims to compare the histological outcomes of three distinct de-epithelialization methods used in (connective tissue grafts) CTG harvested from the palate. MATERIALS AND METHODS: An experimental study using nine cadaver head specimens was carried out to compare 3 different de-epithelialization techniques for CTG. Eighteen samples were randomly allocated to three study groups: bone scraper, diamond bur and extraoral removal with a scalpel. The main outcome variable was the graft surface percentage without epithelium remains. Additionally, the time employed, and the graft thickness were also measured. RESULTS: Sixteen CTGs were analyzed. The extraoral scalpel group presented a total surface area with no epithelium of 58.84% (22.68) and a mean de-epithelialization time of 3.7 min; the intraoral diamond bur group had 88.24% (41.3) of the surface with no epithelium and took 1.455 min, and the intraoral bone scraper showed 97.98% (5.99) of surface without epithelium and a mean time of 0.815 min (P < 0.05). Histological analysis showed significant differences between the bone scraper and the extraoral group (P = 0.009). CONCLUSION: The de-epithelialization technique with a bone scraper seems to be the most effective and fastest de-epithelialization technique for CTG. These findings need to be confirmed in future clinical studies with larger samples. CLINICAL RELEVANCE: The use of bone scrapers, could be a simple, effective and fast technique to de-epithelialize connective tissue grafts harvested from the palatal area for both novice and experienced surgeons.

Rates and predictors of reimplantation of matrix-induced autologous chondrocyte implantation following first stage cartilage harvest: A cohort study.

PURPOSE: To assess the reimplantation rate and predictors of patients requiring second-staged matrix-induced autologous chondrocyte implantation (MACI) reimplantation after initial first stage cartilage biopsy. METHODS: A retrospective review was performed from 2018 to 2022 among patients who underwent only phase I MACI biopsy procedure (biopsy group) or both phase I with transition to phase II implantation of chondrocytes (implantation group) at a single tertiary center. Demographic, qualitative, and quantitative measurements were recorded, and univariate and multivariate regression analysis was performed to assess predictors of ultimately requiring second stage MACI implantation. RESULTS: A total of 71 patients (51% female, age 27.7 ± 10.6 years (range 12-50)) were included in this study. Eventually, 25 of 71 patients (35.2%) experienced persistence of symptoms after initial MACI biopsy and other concomitant procedures, requiring second-stage implantation. Univariate analysis showed the implantation group compared to the biopsy group had a greater lesion size (5.2 cm2 ± 3.3 vs. 3.3 cm2 ± 1.4, p = 0.024), a higher proportion patients ≥ 26 years of age (76% vs. 43%, p = 0.009), a medial femoral condyle lesion more commonly (33% vs 11%, p = 0.005), were more often female (72% vs. 39%, p = 0.008), and had less often soft tissue repair at time of biopsy (32% vs. 61%, p = 0.020). Backward multivariate logistic regression analysis revealed that size of the lesion (OR 1.43, p = 0.031) and age ≥ 26 years old at time of biopsy (OR 3.55, p = 0.042) were independent predictors of not responding to initial surgery and requiring implantation surgery. CONCLUSION: This study found that 35% of patients undergoing MACI phase I biopsy harvest eventually required autologous implantation. Independent risk factors for progressing to implantation after failed initial surgery were larger defect size and older age. LEVEL OF EVIDENCE: III, Cohort Study.

Early Injury Landscape in Vein Harvest by Single-Cell and Spatial Transcriptomics.

BACKGROUND: Vein graft failure following cardiovascular bypass surgery results in significant patient morbidity and cost to the healthcare system. Vein graft injury can occur during autogenous vein harvest and preparation, as well as after implantation into the arterial system, leading to the development of intimal hyperplasia, vein graft stenosis, and, ultimately, bypass graft failure. Although previous studies have identified maladaptive pathways that occur shortly after implantation, the specific signaling pathways that occur during vein graft preparation are not well defined and may result in a cumulative impact on vein graft failure. We, therefore, aimed to elucidate the response of the vein conduit wall during harvest and following implantation, probing the key maladaptive pathways driving graft failure with the overarching goal of identifying therapeutic targets for biologic intervention to minimize these natural responses to surgical vein graft injury. METHODS: Employing a novel approach to investigating vascular pathologies, we harnessed both single-nuclei RNA-sequencing and spatial transcriptomics analyses to profile the genomic effects of vein grafts after harvest and distension, then compared these findings to vein grafts obtained 24 hours after carotid-carotid vein bypass implantation in a canine model (n=4). RESULTS: Spatial transcriptomic analysis of canine cephalic vein after initial conduit harvest and distention revealed significant enrichment of pathways (P<0.05) involved in the activation of endothelial cells (ECs), fibroblasts, and vascular smooth muscle cells, namely pathways responsible for cellular proliferation and migration and platelet activation across the intimal and medial layers, cytokine signaling within the adventitial layer, and ECM (extracellular matrix) remodeling throughout the vein wall. Subsequent single-nuclei RNA-sequencing analysis supported these findings and further unveiled distinct EC and fibroblast subpopulations with significant upregulation (P<0.05) of markers related to endothelial injury response and cellular activation of ECs, fibroblasts, and vascular smooth muscle cells. Similarly, in vein grafts obtained 24 hours after arterial bypass, there was an increase in myeloid cell, protomyofibroblast, injury response EC, and mesenchymal-transitioning EC subpopulations with a concomitant decrease in homeostatic ECs and fibroblasts. Among these markers were genes previously implicated in vein graft injury, including VCAN, FBN1, and VEGFC, in addition to novel genes of interest, such as GLIS3 and EPHA3. These genes were further noted to be driving the expression of genes implicated in vascular remodeling and graft failure, such as IL-6, TGFBR1, SMAD4, and ADAMTS9. By integrating the spatial transcriptomics and single-nuclei RNA-sequencing data sets, we highlighted the spatial architecture of the vein graft following distension, wherein activated and mesenchymal-transitioning ECs, myeloid cells, and fibroblasts were notably enriched in the intima and media of distended veins. Finally, intercellular communication network analysis unveiled the critical roles of activated ECs, mesenchymal-transitioning ECs, protomyofibroblasts, and vascular smooth muscle cells in upregulating signaling pathways associated with cellular proliferation (MDK [midkine], PDGF [platelet-derived growth factor], VEGF [vascular endothelial growth factor]), transdifferentiation (Notch), migration (ephrin, semaphorin), ECM remodeling (collagen, laminin, fibronectin), and inflammation (thrombospondin), following distension. CONCLUSIONS: Vein conduit harvest and distension elicit a prompt genomic response facilitated by distinct cellular subpopulations heterogeneously distributed throughout the vein wall. This response was found to be further exacerbated following vein graft implantation, resulting in a cascade of maladaptive gene regulatory networks. Together, these results suggest that distension initiates the upregulation of pathological pathways that may ultimately contribute to bypass graft failure and presents potential early targets warranting investigation for targeted therapies. This work highlights the first applications of single-nuclei and spatial transcriptomic analyses to investigate venous pathologies, underscoring the utility of these methodologies and providing a foundation for future investigations.