Characterization of a full-thickness decellularized and lyophilized human placental membrane for clinical applications.

Allografts derived from live-birth tissue obtained with donor consent have emerged as an important treatment option for wound and soft tissue repairs. Placental membrane derived from the amniotic sac consists of the amnion and chorion, the latter of which contains the trophoblast layer. For ease of cleaning and processing, these layers are often separated with or without re-lamination and the trophoblast layer is typically discarded, both of which can negatively affect the abundance of native biological factors and make the grafts difficult to handle. Thus, a full-thickness placental membrane that includes a fully-intact decellularized trophoblast layer was developed for homologous clinical use as a protective barrier and scaffold in soft tissue repairs. Here, we demonstrate that this full-thickness placental membrane is effectively decellularized while retaining native extracellular matrix (ECM) scaffold and biological factors, including the full trophoblast layer. Following processing, it is porous, biocompatible, supports cell proliferation in vitro, and retains its biomechanical strength and the ability to pass through a cannula without visible evidence of movement or damage. Finally, it was accepted as a natural scaffold in vivo with evidence of host-cell infiltration, angiogenesis, tissue remodelling, and structural layer retention for up to 10 weeks in a murine subcutaneous implant model.

Lumbar spine fusion outcomes using a cellular bone allograft with lineage-committed bone-forming cells in 96 patients.

BACKGROUND: Instrumented posterior lumbar fusion (IPLF) with and without transforaminal interbody fusion (TLIF) is a common treatment for low back pain when conservative interventions have failed. Certain patient comorbidities and lifestyle risk factors, such as obesity and smoking, are known to negatively affect these procedures. An advanced cellular bone allograft (CBA) with viable osteogenic cells (V-CBA) has demonstrated high fusion rates, but the rates for patients with severe and/or multiple comorbidities remain understudied. The purpose of this study was to assess fusion outcomes in patients undergoing IPLF/TLIF using V-CBA with baseline comorbidities and lifestyle risk factors known to negatively affect bone fusion. METHODS: This was a retrospective study of de-identified data from consecutive patients at an academic medical center who underwent IPLF procedures with or without TLIF, and with V-CBA. Baseline patient and procedure characteristics were assessed. Radiological outcomes included fusion rates per the Lenke scale. Patient-reported clinical outcomes were evaluated via the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain. Operating room (OR) times and intraoperative blood loss rates were also assessed. RESULTS: Data from 96 patients were assessed with a total of 222 levels treated overall (mean: 2.3 levels) and a median follow-up time of 16 months (range: 6 to 45 months). Successful fusion (Lenke A or B) was reported for 88 of 96 patients (91.7%) overall, including in all IPLF-only patients. Of 22 patients with diabetes in the IPLF+TLIF group, fusion was reported in 20 patients (90.9%). In IPLF+TLIF patients currently using tobacco (n = 19), fusion was reported in 16 patients (84.3%), while in those with a history of tobacco use (n = 53), fusion was observed in 48 patients (90.6%). Successful fusion was reported in all 6 patients overall with previous pseudarthrosis at the same level. Mean postoperative ODI and VAS scores were significantly reduced versus preoperative ratings. CONCLUSION: The results of this study suggest that V-CBA consistently yields successful fusion and significant decreases in patient-reported ODI and VAS, despite patient comorbidities and lifestyle risk factors that are known to negatively affect such bony healing.

Histologic case series of human acellular dermal matrix in superior capsule reconstruction.

BACKGROUND: Acellular dermal matrix (ADM) allografts are commonly used in the surgical treatment of complex and irreparable rotator cuff tears. Multiple studies report that superior capsule reconstruction (SCR) using ADM has resulted in short-term clinical success as assessed via radiographic and patient-reported outcomes. However, limited information is available regarding the biologic fate of these grafts in human subjects. This case series describes histologic results from 8 patients who had reoperations, during which the previously implanted ADMs were removed. These explanted ADMs were subjected to histologic analysis with the hypothesis that they would have evidence of recellularization, revascularization, and active remodeling. METHODS: Eight patients, 38-82 years old, underwent reoperation 6-38 months after undergoing SCR. ADM explants were voluntarily shipped to the manufacturer for histologic analysis. Each graft's structure and composition were qualitatively evaluated by 1 or more of the following histologic stains: hematoxylin and eosin, safranin O, and Russell-Movat pentachrome. Pan-muscle actin staining also assessed the level of neovascularization, potential myoblast or myocyte infiltration, and muscle tissue development in the graft, and was analyzed to determine the proportion of graft that had been recellularized in situ. RESULTS: Grafts showed varying levels of gross and microscopic incorporation with the host. An uneven, but high, overall degree of recellularization, revascularization, and active remodeling was observed. The degree of remodeling correlated with implant duration. These results are consistent with successful biologic reconstruction of the superior shoulder capsule. CONCLUSIONS: The present histologic analysis suggests that ADMs used in SCR undergo active recellularization, revascularization, and remodeling as early as 6 months after implantation, and that graft recellularization positively correlates with duration of implantation. These results represent a significant advancement in our knowledge regarding biologic incorporation of ADMs used in SCR.

Randomized Comparative Assessment of Three Surgical Cricothyrotomy Devices on Airway Mannequins.

BACKGROUND: Airway obstruction is the second leading cause of preventable battlefield death, at least in part because surgical cricothyrotomy (SC) failure rates remain unacceptably high. Ideally, SC should be a rapid, simple, easily-learned, and reliably-performed procedure. Currently, 3 SC devices meet Tactical Combat Casualty Care (TCCC) standards: The Tactical CricKit® (TCK), Control-CricTM(CC), and Bougie-assisted Technique (BAT). However, no previous studies have compared these devices in application time, application success, user ratings, and user preference. METHODS: United States Navy Corpsmen (N = 25) were provided 15 minutes of standardized instruction, followed by hands-on practice with each device on airway mannequins. Participants then performed SC with each of the 3 devices in a randomly assigned sequence. In this within-subjects design, application time, application success, participant ratings, and participant preference data were analyzed using repeated-measures ANOVA, regression, and non-parametric statistics at p < 0.05. RESULTS: Application time for CC (M = 184 sec, 95% CI 144-225 sec) was significantly slower than for BAT (M = 135 sec, 95% CI 113-158 sec, p < 0.03) and TCK (M = 117 sec, 95% CI 93-142 sec, p < 0.005). Success was significantly greater for BAT (76%) than for TCK (40%, p < 0.02) and trended greater than CC (48%, p = 0.07). CC was rated significantly lower than TCK and BAT in ease of application, effectiveness, and reliability (each p < 0.01). User preference was significantly (p < 0.01) higher for TCK (58%) and BAT (42%) than for CC (0%). Improved CC blade design was the most common user suggestion. CONCLUSION: While this study was limited by the use of mannequins in a laboratory environment, present results indicate that none of these devices was ideal for performing SC. Based on slow application times, low success rates, and user feedback, the Control-CricTM cannot be recommended until improvements are made to the blade design.

Health economics for treatment of diabetic foot ulcers: a cost-effectiveness analysis of eight skin substitutes.

AIM: Skin substitutes are frequently used to treat chronic diabetic foot ulcers (DFU), and many different options are available. While the clinical efficacy of many products has been evaluated, a comprehensive cost-effectiveness analysis comparing the most popular skin substitutes and using the most recent cost data has been lacking. METHODS: This study compared eight skin substitutes using published efficacy rates combined with the Centers for Medicare and Medicaid Services (CMS) 2018 cost data. The study criteria resulted in the inclusion of seven studies that described efficacy rates for treatment of DFUs using the skin substitutes. RESULTS: The results revealed wide discrepancies between these skin substitutes for the costs of treatments and healing rates in hospital outpatient departments and physician office settings. Healing rates for 12 and 16 weeks ranged from 28% to 68%, while the average cost for treating one DFU varied from $2001 to $14,507 and $1207 to $8791 in the hospital outpatient department and physician's office setting, respectively. The estimated patient share of costs for treating a single DFU ranged from $400 to $2901 and $241 to $1758 in the hospital outpatient department and physician's office setting, respectively. Most importantly, the estimated number of wounds healed out of 100 DFUs per $1000 expenditure with each patient ranged from 3.9-26.5 DFUs in the hospital outpatient department, and 4.3-36.4 DFUs in the physicians' office setting. CONCLUSIONS: This study revealed that the costs of a skin substitute itself did not necessarily correlate with its healing efficacy. These results provide a comprehensive cost-effectiveness analysis to enable integrated health-care systems, health professionals and reimbursement payers to make informed value decisions when treating DFUs.

A Prospective, Multicenter, Single-Arm Clinical Trial for Treatment of Complex Diabetic Foot Ulcers with Deep Exposure Using Acellular Dermal Matrix.

OBJECTIVE: This prospective, multicenter study evaluated the efficacy and safety of an acellular dermal matrix allograft, DermACELL (D-ADM; LifeNet Health, Virginia Beach, Virginia), in the treatment of large, complex diabetic foot ulcers (DFUs) that probed to tendon or bone. METHODS: Inclusion criteria were Wagner grade 3 or 4 DFUs between 4 weeks and 1 year in duration. All participants received one application of D-ADM at baseline and could receive one additional application if wound healing arrested. Ulcers were assessed weekly for 16 weeks using a laser measuring device. RESULTS: Sixty-one participants were enrolled, with an average wound area of 29.0 cm; 59 of these ulcers showed exposed bone. The entire per-protocol population (n = 47) achieved 100% granulation. The mean time to 100% granulation was 4.0 weeks with an average of 1.2 applications of D-ADM. Mean percent wound area reduction was 80.3% at 16 weeks. Those DFUs 15 cm or smaller were substantially more likely to close than DFUs larger than 29 cm (P = .0008) over a 16-week duration. No complications were associated with the use of the studied matrix. CONCLUSIONS: The D-ADM demonstrated the ability to rapidly reduce the size of large, complex DFUs with exposed bone. Some wounds did not completely heal by 16 weeks; however, the significant reduction in size suggests that these large, complex wounds may heal if given more time.

Family presence during resuscitation in a paediatric hospital: health professionals' confidence and perceptions.

AIMS AND OBJECTIVES: To investigate medical and nursing staff's perceptions of and self-confidence in facilitating family presence during resuscitation in a paediatric hospital setting. BACKGROUND: Family presence during resuscitation is the attendance of family members in a location that affords visual or physical contact with the patient during resuscitation. Providing the opportunity for families to be present during resuscitation embraces the family-centred care philosophy which underpins paediatric care. Having families present continues to spark much debate amongst health care professionals. DESIGN: A descriptive cross-sectional randomised survey using the 'Family Presence Risk/Benefit Scale' and the 'Family Presence Self-Confidence Scale 'to assess health care professionals' (doctors and nurses) perceptions and self-confidence in facilitating family presence during resuscitation of a child in a paediatric hospital. METHODS: Surveys were distributed to 300 randomly selected medical and nursing staff. Descriptive and inferential statistics were used to compare medical and nursing, and critical and noncritical care perceptions and self-confidence. RESULTS: Critical care staff had statistically significant higher risk/benefit scores and higher self-confidence scores than those working in noncritical care areas. Having experience in paediatric resuscitation, having invited families to be present previously and a greater number of years working in paediatrics significantly affected participants' perceptions and self-confidence. There was no difference between medical and nursing mean scores for either scale. CONCLUSION: Both medical and nursing staff working in the paediatric setting understood the needs of families and the philosophy of family-centred care is a model of care practised across disciplines. RELEVANCE TO CLINICAL PRACTICE: This has implications both for implementing guidelines to support family presence during resuscitation and for education strategies to shift the attitudes of staff who have limited or no experience.

iTClamp-Mediated Wound Closure Speeds Control of Arterial Hemorrhage With or Without Additional Hemostatic Agents.

BACKGROUND: Exsanguination is the leading cause of preventable posttraumatic death, especially in the prehospital arena. Traditional hemorrhage control methods involve packing the wound with hemostatic agents, providing manual pressure, and then applying a pressure dressing to stabilize the treatment. This is a lengthy process that frequently destabilizes upon patient transport. Conversely, the iTClamp, a compact wound closure device, is designed to rapidly seal wound edges mechanically, expediting clot formation at the site of injury. OBJECTIVES: To determine the efficacy of the iTClamp with and without wound packing in the control of a lethal junction hemorrhage. METHODS: Given the limited available information regarding the efficacy of the iTClamp in conjunction with traditional hemostatic agents, this study used a swine model of severe junctional hemorrhage. The goal was to compare a multiagent strategy using the iTClamp in conjunction with XSTAT to the traditional method of Combat Gauze packing with pressure dressing application. Readouts include application time, blood loss, and rebleed occurrence. RESULTS: Mean application times of the iTClamp treatment alone or in conjunction with other hemostatic agents were at least 75% faster than the application time of Combat Gauze with pressure dressing. Percent blood loss was not significantly different between groups but trended the highest for Combat Gauze treated swine, followed by iTClamp plus XSTAT, iTClamp alone and finally iTClamp plus Combat Gauze. CONCLUSION: The results from this study demonstrate that the iTClamp can be effectively utilized in conjunction with hemostatic packing to control junctional hemorrhages.

A 24-month retrospective update: follow-up hospitalization charges and readmissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2).

BACKGROUND: The objectives of this study were to build upon previously-reported 12-month findings by retrospectively comparing 24-month follow-up hospitalization charges and potentially-relevant readmissions in US lumbar fusion surgeries that employed either recombinant human bone morphogenetic protein-2 (rhBMP-2) or a cellular bone allograft comprised of viable lineage-committed bone cells (V-CBA) via a nationwide healthcare system database. METHODS: A total of 16,172 patients underwent lumbar fusion surgery using V-CBA or rhBMP-2 in the original study, of whom 3,792 patients (23.4%) were identified in the current study with all-cause readmissions during the 24-month follow-up period. Confounding baseline patient, procedure, and hospital characteristics found in the original study were used to adjust multivariate regression models comparing differences in 24-month follow-up hospitalization charges (in 2020 US dollars) and lengths of stay (LOS; in days) between the groups. Differences in potentially-relevant follow-up readmissions were also compared, and all analyses were repeated in the subset of patients who only received treatment at a single level of the spine. RESULTS: The adjusted cumulative mean 24-month follow-up hospitalization charges in the full cohort were significantly lower in the V-CBA group ($99,087) versus the rhBMP-2 group ($124,389; P < 0.0001), and this pattern remained in the single-level cohort (V-CBA = $104,906 vs rhBMP-2 = $125,311; P = 0.0006). There were no differences between groups in adjusted cumulative mean LOS in either cohort. Differences in the rates of follow-up readmissions aligned with baseline comorbidities originally reported for the initial procedure. Subsequent lumbar fusion rates were significantly lower for V-CBA patients in the full cohort (10.12% vs 12.00%; P = 0.0002) and similar between groups in the single-level cohort, in spite of V-CBA patients having significantly higher rates of baseline comorbidities that could negatively impact clinical outcomes, including bony fusion. CONCLUSIONS: The results of this study suggest that use of V-CBA for lumbar fusion surgeries performed in the US is associated with substantially lower 24-month follow-up hospitalization charges versus rhBMP-2, with both exhibiting similar rates of subsequent lumbar fusion procedures and potentially-relevant readmissions.

Red-Green Tactical Lighting Is Preferred for Suturing Wounds in a Simulated Night Environment.

BACKGROUND: Delivering medical care in nighttime conditions is challenging, as 25% of Special Operations medical Operators have reported that problems with lighting contributed to poor casualty outcomes. Red light is often used in nighttime operations but makes blood detection difficult and diminishes depth perception and visual acuity. Red-green combination lighting may be superior for differentiating blood from tissue and other fluids but had not been tested versus red-only or green-only lighting for combat-related medical procedures, such as wound suturing. METHODS: Dark-adapted medical resident physicians (N = 24) sutured 6cm long, 3cm deep, full-thickness lacerations in deceased swine under red-only, green-only, and red-green lighting provided by a tactical flashlight using a randomized within-subjects design. Time to suture completion, suture quality, user ratings, and user preference data were contrasted at p < .05. This study was approved by Naval Medical Center Portsmouth IRB. RESULTS: Suture completion time and suture quality were similar across all lighting conditions. Participants rated red-green lighting as significantly easier for identifying blood, identifying instruments, and performing suturing (p < .01). Red-green lighting was preferred by 83% of participants compared to 8% each for red-only and green-only (p < .001). CONCLUSIONS: Pending further study under tactical conditions, red-green lighting is tentatively recommended for treating battlefield wounds in low-light environments.

Short-term disruption in regional left ventricular electrical conduction patterns increases interstitial matrix metalloproteinase activity.

Increased matrix metalloproteinase (MMP) abundance occurs with adverse left ventricular (LV) remodeling in a number of cardiac disease states, including those induced by long-standing arrhythmias. However, whether regionally contained aberrant electrical activation of the LV, with consequent dyskinesia, alters interstitial MMP activation remained unknown. Electrical activation of the LV of pigs (n = 10, 30-35 kg) was achieved by pacing (150 beats/min) at left atrial and LV sites such that normal atrioventricular activation (60 min) was followed by regional early LV activation for 60 min within 1.5 cm of the paced site and restoration of normal atrioventricular pacing for 120 min. Regional shortening (piezoelectric crystals) and interstitial MMP activity (microdialysis with MMP fluorogenic substrate) at the LV pacing site and a remote LV site were monitored at 30-min intervals. During aberrant electrical stimulation, interstitial MMP activity at the paced site was increased (122 +/- 4%) compared with the remote region (100%, P < 0.05). Restoration of atrioventricular pacing after the 60-min period of aberrant electrical activation normalized segmental shortening (8.5 +/- 0.4%), but MMP activity remained elevated (121 +/- 6%, P < 0.05). This study demonstrates that despite the restoration of mechanical function, disturbances in electrical conduction, in and of itself, can cause acute increases in regional in vivo MMP activation and, therefore, contribute to myocardial remodeling.

A large database study of hospitalization charges and follow-up re-admissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2).

BACKGROUND: The objective of this study was to retrospectively compare initial procedure and 12-month follow-up hospitalization charges and resource utilization (lengths of stay; LOS) for lumbar fusion surgeries using either recombinant human bone morphogenetic protein-2 (rhBMP-2) or a cellular bone allograft comprised of viable lineage-committed bone cells (V-CBA) via a large US healthcare system database. Potentially relevant re-admissions during the follow-up period were also assessed. METHODS: A total of 16,172 patients underwent lumbar fusion surgery using V-CBA or rhBMP-2, of whom 3503 (21.66%) patients had follow-up re-admission data. Initial patient, procedure, and hospital characteristics were assessed to determine confounding factors. Multivariate regression modeling compared differences in hospitalization charges (in 2018 US dollars) and LOS (in days) between the groups, as well as incidences of potentially relevant re-admissions during the 12-month follow-up period. RESULTS: The adjusted mean initial procedure and 12-month follow-up hospital charges were significantly lower in the V-CBA group versus the rhBMP-2 group ($109,061 and $108,315 versus $160,191 and $130,406, respectively; P < 0.0001 for both comparisons). This disparity remained in an ad hoc comparison of charges for initial single-level treatments only (V-CBA = $103,064, rhBMP-2 = $149,620; P < 0.0001). The adjusted mean initial LOS were significantly lower in the V-CBA group (3.77 days) versus the rhBMP-2 group (3.88 days; P < 0.0001), but significantly higher for the cumulative follow-up hospitalizations in the 12-month follow-up period (7.87 versus 7.46 days, respectively; P < 0.0001). Differences in rates of follow-up re-admissions aligned with comorbidities at the initial procedure. Subsequent lumbar fusion rates were comparable, but significantly lower for V-CBA patients who had undergone single-level treatments only, in spite of V-CBA patients having significantly higher rates of initial comorbidities that could negatively impact clinical outcomes. CONCLUSIONS: The results of this study indicate that use of V-CBA for lumbar fusion surgeries performed in the US may result in substantially lower overall hospitalization charges versus rhBMP-2, with both exhibiting similar rates of 12-month re-admissions and subsequent lumbar fusion procedures.

Clinical outcome and explant histology after using a cellular bone allograft in two-stage total hip arthroplasty.

BACKGROUND: Although use of cellular bone allografts (CBA) in orthopedic surgery has become increasingly common, little information is available regarding their short-term clinical performance. In these two case reports of two-stage hip arthroplasties, ViviGen Formable CBA (V-CBA) was used in stage one to fill voids left by previous metal implants. METHODS: The two patients had distinctly different health profiles, but each of them had previous metal implants due to a hip fracture. In the otherwise healthy 49-year-old male patient, the total hip arthroplasty (THA) was performed 7 weeks after nail removal and V-CBA backfill. In the 64-year-old female patient with Type 1 diabetes and severe osteoporosis, stage 2 was performed after 12 weeks. At the time of THA for each patient, bone containing some V-CBA was removed to accommodate the hip implant. The explants were histologically analyzed for bone matrix, mineralization, and neovascularization. RESULTS: Histological staining showed substantial new bone formation and neovascularization in both explants albeit at different levels of maturity. CONCLUSIONS: Although limited, these results suggest that V-CBA may facilitate new bone formation in healthy as well as in metabolically challenged patients. LEVEL OF EVIDENCE: V, case report.

Aprotinin modifies left ventricular contractility and cytokine release after ischemia-reperfusion in a dose-dependent manner in a murine model.

BACKGROUND: Periods of ischemia-reperfusion (I/R) during cardiac surgery are associated with transient left ventricular (LV) dysfunction and an inflammatory response. In this study, we examined the potential dose-dependent effects of aprotinin (APRO) on LV contractility and cytokine release in the setting of I/R. METHODS: An index of LV contractility, LV maximal elastance (E(max)), was measured at baseline, 30 min of ischemia, and 60 min of reperfusion by microtransducer volumetry. Mice were randomized as follows: (a) APRO 20,000 kallikrein-inhibiting units (KIU)/kg (n = 11); (b) APRO 4 x 10(4) KIU/kg (n = 10); (c) APRO 8 x 10(4) KIU/kg (n = 10); and (d) vehicle (saline; n = 10). APRO doses were calculated to reflect half, full, and twice the clinical Hammersmith dosing schedule. After I/R, plasma was collected for cytokine measurements. RESULTS: After I/R, E(max) decreased from the baseline value by more than 40% in the vehicle group as well as in the APRO 4 x 10(4) KIU/kg and APRO 8 x 10(4) KIU/kg groups (P < 0.05). However, E(max) returned to near baseline values in the APRO 2 x 10(4) KIU/kg group. Tumor necrosis factor (TNF) increased 10-fold after I/R, but it was reduced with higher APRO doses. CONCLUSIONS: This study demonstrated that a low dose of APRO provided protective effects on LV contractility, whereas higher doses suppressed TNF release. These unique findings suggest that there are distinct and independent mechanisms of action of APRO in the context of I/R.

Pilot Study of a Novel Swine Model for Controlling Junctional Hemorrhage Using the iTClamp in Conjunction With Hemostatic Agents.

Exsanguinating hemorrhage is a primary cause of battlefield death. The iTClamp is a relatively new device (FDA approval in 2013) that takes a different approach to hemorrhage control by applying mechanism wound closure. However, no previous studies have explored the feasibility of utilizing the iTClamp in conjunction with hemostatic packing. To fill this important gap in the literature, a novel swine model was developed, and a total of 12 trials were performed using QuikClot Combat Gauze or XSTAT sponges in conjunction with the iTClamp to treat arterial injuries through 5 cm or 10 cm skin incisions in the groin, axilla, or neck. First-attempt application success rate, application time, and blood loss were recorded. Hemostasis was achieved on all wounds, though reapplication was required in one Combat Gauze and three XSTAT applications. Application averaged ~50% slower for Combat Gauze (M = 41 seconds, 95%CI: 22-32 seconds) than for XSTAT (M = 27 seconds, 95%CI: 35-47 seconds). XSTAT application was faster than Combat Gauze for each wound location and size. The 10 cm wounds took ~10 seconds (36%) longer to close (M = 27 seconds, 95%CI: 35-47 seconds) than the 5 cm wounds (M = 27 seconds, 95%CI: 35-47 seconds). Blood loss was similar for Combat Gauze (M = 51 mL, 95%CI: 25-76 mL) and XSTAT (M = 60 mL, 95%CI: 30-90 mL). Blood loss was roughly twice as great for 10 cm wounds (M = 73 mL, 95%CI: 47-100 mL) than for 5 cm wounds (M = 38 mL, 95%CI: 18-57 mL). This pilot study supports the feasibility of a novel model for testing the iTClamp in conjunction with hemostatic packing towards controlling junctional hemorrhage.

Multilevel instrumented posterolateral lumbar spine fusion with an allogeneic cellular bone graft.

BACKGROUND: Low back pain (LBP) is the leading cause of absence from work, disability, and impaired quality of life. Fusion surgery may be indicated when non-operative treatments have failed to provide relief. Surgery may include the use of fusion-enhancing implants, such as cellular bone allografts (CBAs). The purpose of this retrospective study was to evaluate efficacy and safety of one CBA (V-CBA) in patients who underwent instrumented posterolateral fusion (IPLF). METHODS: Retrospective data were collected from 150 consecutive patients who had undergone IPLF surgery between January 1, 2015, and March 31, 2018, in which V-CBA was used. All surgeries were performed by one surgeon. V-CBA was mixed with local autograft bone. Patient diagnoses included degenerative disc disease, spondylosis, spondylolisthesis, or spondylolysis with or without stenosis. Standing anteroposterior (AP) and lateral images were collected prior to surgery and again at the terminal visit, which took place between 6 and 33 months post-operatively. De-identified images were assessed radiologically. Adverse events were documented. The primary composite endpoint of fusion status was dependent upon two main criteria: bridging bone per the Lenke scale (classified as "A" definitely solid or "B" possibly solid) and posterior hardware status (intact). Lenke scale C or D were categorized as pseudarthrosis. RESULTS: Eighty-seven male and 63 female patients (613 levels total) underwent IPLF in which V-CBA was implanted. An average of 4.1 levels was treated, with 59.3% of patients having undergone treatment for more than 3 levels. Twenty-nine percent of patients had diabetes. Fifty-two percent of patients had previously used nicotine products, and 12% were current smokers. Sixteen serious adverse events were recorded and included lumbar seroma, cerebrospinal fluid leak, wound dehiscence, pneumonia, urinary tract infection, and myocardial infarction. Successful fusion (Lenke scale "A" or "B") was recorded in 148 out of 150 patients (98.7%), or 608 out of 613 levels. The total pseudarthrosis rate was 0.8%. CONCLUSIONS: The use of V-CBA combined with local autograft in multilevel IPLF resulted in successful fusions in 98.7% of patients. These results are particularly robust given the complex nature of many of these cases: 89 patients had 4 or more surgical levels, and many patients had multiple comorbidities. LEVEL OF EVIDENCE: IV.

Preservation of allograft bone using a glycerol solution: a compilation of original preclinical research.

BACKGROUND: Bone allografts are used in many orthopedic procedures to provide structural stability as well as an osteoconductive matrix for bone ingrowth and fusion. Traditionally, bone allografts have been preserved by either freezing or freeze-drying. Each of these preservation methods has some disadvantages: Frozen grafts require special shipping and storage conditions, and freeze-drying requires special lyophilization equipment and procedures that may impact biomechanical integrity. This report describes an alternate type of preservation using glycerol, which allows storage of fully-hydrated tissues at ambient temperature avoiding the potential complications from freeze-drying. METHODS: In the in vitro three-point bend test, cortical bone was processed and frozen, freeze-dried, or treated with glycerol-based preservation (GBP). Load was applied to each graft at a rate of 2.71 mm/min. The flexural strain, flexural strength, and flexural modulus were then calculated. In the in vitro axial compression test, iliac crest wedges, fibular segments, and Cloward dowels were processed and either freeze-dried or GBP treated. The compressive strength of the grafts were tested at time zero and after real time aging of 1, 4, and 5 years. In the in vivo rat calvarial defect assessment, freeze-dried, frozen, and GBP bone implants were compared after being implanted into a critical sized defect. Samples underwent histological and biomechanical evaluation. RESULTS: Bone grafts subjected to GBP were found to be at least biomechanically equivalent to frozen bone while also being significantly less brittle than freeze-dried bone. GBP-preserved bone demonstrated significantly greater compressive strength than freeze-dried at multiple time points. Preclinical research performed in calvaric defect models found that GBP-preserved bone had similar osteoconductivity and biocompatibility to frozen and freeze-dried samples. CONCLUSION: Preclinical research demonstrated that glycerol-preservation of bone yields a material that maintains biomechanical strength while eliminating the need for extensive rehydration or thaw periods if used clinically. Additionally, in vivo evidence suggests no negative impact of glycerol-preservation on the ability of bone grafts to successfully participate in new bone formation and fusion.

A Pilot Study of Four Intraosseous Blood Transfusion Strategies.

BACKGROUND: Intraosseous (IO) access is used by military first responders administering fluids, blood, and medications. Current IO transfusion strategies include gravity, pressure bags, rapid transfusion devices, and manual push-pull through a three-way stopcock. In a swine model of hemorrhagic shock, we compared flow rates among four different IO blood transfusion strategies. METHODS: Nine Yorkshire swine were placed under general anesthesia. We removed 20 to 25mL/kg of each animal's estimated blood volume using flow of gravity. IO access was obtained in the proximal humerus. We then autologously infused 10 to 15mL/kg of the animal's estimated blood volume through one of four randomly assigned treatment arms. RESULTS: The average weight of the swine was 77.3kg (interquartile range, 72.7kg-88.8kg). Infusion rates were as follows: gravity, 5mL/min; Belmont rapid infuser, 31mL/min; single-site pressure bag, 78mL/min; double-site pressure bag, 103mL/min; and push-pull technique, 109mL/min. No pulmonary arterial fat emboli were noted. CONCLUSION: The optimal IO transfusion strategy for injured Servicemembers appears to be single-site transfusion with a 10mL to 20mL flush of normal saline, followed immediately by transfusion under a pressure bag. Further study, powered to detect differences in flow rate and clinical complications. is required.

Protein kinase C isoform activation and endothelin-1 mediated defects in myocyte contractility after cardioplegic arrest and reperfusion.

BACKGROUND: Endothelin-1 (ET-1) is released after hyperkalemic cardioplegic arrest (CA) and reperfusion and may contribute to contractile dysfunction. ET-1 receptor transduction causes activation of protein kinase C (PKC) isoforms, which can cause differential intracellular events. The goal of this study was to determine which PKC isoforms contribute to myocyte contractile dysfunction with ET-1 and CA. METHODS AND RESULTS: Percent shortening (PERSHORT) and the time to 50% relaxation (T50) were measured in porcine (n =22) left ventricular myocytes, randomized (minimum: 30 cells/group) to normothermia: (cell media for 2 hours/37 degrees C), and CA: (2 hours/4 degrees C, 24 mEq K+ solution followed by reperfusion in cell media), ET-1/CA: (100 pM ET-1 during CA). Studies were performed in the presence and absence of PKC inhibitors (500 nM) against the classical (Beta-I, Beta-II, Gamma) and novel (Epsilon, Eta) isoforms (myocytes from a minimum of 3 pigs per inhibitor). CA reduced PERSHORT by approximately 35% from normothermia (P<0.05), which was further reduced with ET-1. PKC-Beta-II or PKC-Gamma inhibition increased PERSHORT from ET-1/CA as well as CA only (P<0.05). CA prolonged T50 by approximately 19% from normothermia (P<0.05) and was further prolonged with ET-1. Inhibition of the classical PKC isoforms reduced T50 from ET-1/CA (P<0.05). Inhibition of novel PKC isoforms did not yield similar effects on either PERSHORT or T50 with ET-1/CA. CONCLUSIONS: Inhibition of the classical PKC isoforms relieved the negative inotropic and lusitropic effects of ET-1 after CA. These findings provide mechanistic support for developing targeted inhibitory strategies with respect to ET-1 signaling and myocyte contractile dysfunction with cardioplegic arrest and reperfusion.

Myocardial interstitial matrix metalloproteinase activity is altered by mechanical changes in LV load: interaction with the angiotensin type 1 receptor.

LV myocardial remodeling is a structural hallmark of hypertensive hypertrophy, but molecular mechanisms driving this process are not well understood. The matrix metalloproteinases (MMPs) can cause myocardial remodeling in chronic disease states, but how MMP activity is altered with a mechanical load remains unknown. The present study quantified interstitial MMP activity after a discrete increase in LV load and dissected out the contributory role of the angiotensin II Type 1 receptor (AT1R). Pigs (38 kg) were randomized to undergo (1) increased LV load by insertion of an intra-aortic balloon pump (IABP) triggered at systole for 3 hours, then deactivated (n=11); (2) IABP and AT1R blockade (AT1RB; valsartan, 3 ng/kg/hr; n=6). MMP activity was directly measured in the myocardial interstitium using a validated inline digital fluorogenic microdialysis system. IABP engagement increased LV peak pressure from 92+/-3 to 113+/-5 and 123+/-7 mm Hg in the vehicle and AR1RB group, respectively, and remained elevated throughout the IABP period (P<0.05). With IABP disengagement, segmental shortening (% change from baseline of 0) remained depressed in the vehicle group (-32.2+/-11.8%, P<0.05) but returned to baseline in the AT1RB group (2.3+/-12.5%). MMP activity decreased with IABP in both groups. At IABP disengagement, a surge in MMP activity occurred in the vehicle group that was abrogated with AT1RB (3.03+/-0.85 versus 0.07+/-1.55 MMP units/hr, P<0.05). A transient increase in LV load caused a cyclic variation in interstitial MMP activity that is regulated in part by the AT1R. These temporally dynamic changes in MMP activity likely influence myocardial function and structure with increased LV load.