Use of a Novel Tissue Oxygen Tension Biosensor to Reliably Predict Healing of Lower Extremity Amputations for Rapid Facilitation of Patient Mobility

继发于血管受损的主要下肢截肢手术表明 极高的感染率、伤口并发症、死亡率和再手术率，导致 活动能力、心血管功能失调和肌肉无力，降低了未来的可能性 假肢装配。这反过来又导致生活质量下降和医疗保健增加 退伍军人健康管理局的支出。 虽然多种因素会导致伤口愈合延迟或失败，但众所周知，肢体灌注是一个关键因素 残肢愈合的组成部分。踝臂指数 (ABI) 和经皮氧分压 (TCPO2) 测量可用于量化肢体灌注并有助于确定需求 对于截肢，文献对于这些值在预测截肢方面的效用存在冲突 残端愈合，没有建立明确的关联。没有可靠客观的方法来预测 愈合的可能性，截肢的程度由手术外科医生根据临床情况确定 对皮肤和组织完整性、质量和灌注的主观（即视觉）评估。 本研究介绍了一种结合光学分析的可注射皮下生物传感技术 数据采集系统将立即检测临床相关的组织氧合张力 特定的解剖平面。这项研究的总体假设是准确的实时 通过使用新型植入式生物传感器获得的组织氧张力的测量是 确定适当截肢水平的重要组成部分，促进快速 残肢的初步愈合，从而为退伍军人提供早期康复的途径 活动能力、增加假肢安装的可能性以及改善功能。 本研究的目的是 1) 将生物传感器测量到的组织氧张力与低于 1 厘米的组织氧张力相关联。 临床确定的截肢水平，并确定初步愈合的临床终点 手术切口/伤口，需要局部伤口护理的手术切口/伤口的二次愈合 无需再次手术、伤口翻修再次手术、翻修截肢再次手术 更近的水平； 2) 建立生物传感器获取数据的可靠性和响应能力 皮下植入下肢时准确读取组织氧张力 人类受试者和 3) 建立组织氧张力使用的初步指南 与再截肢的协变量风险评分相结合，以指导术前确定 最适合预测下肢一期愈合的截肢水平 截肢残肢，加快假肢安装和活动能力，最大限度地减少并发症发生率，以及 减少相关成本。 根据目前的护理标准，截肢水平将由手术外科医生根据 周围组织外观的临床判断（皮肤完整性、水肿程度、 感染或慢性溃疡（如果存在）的近端范围，以及肢体的颜色）。水平 截肢不会因参与研究而改变。两个生物传感器将被插入 每个解剖血管体的皮下组织通过无菌 19 号针头距计划尾部 1 厘米 切口。在实验开始前立即从每个传感器记录组织氧张力 手术过程以及止血带充气后立即再次进行。手术截肢 手术将按常规进行，手术计划不会改变标准护理。学习 术后随访将持续3个月； 3个月时的临床终点将与 术中测量的组织氧张力略低于截肢水平。

Major lower extremity amputation procedures secondary to compromised vascularity demonstrate extremely high rates of infection, wound complication, mortality, and reoperation, resulting in reduced mobility, cardiovascular deconditioning, and muscle weakness, decreasing the probability of future prosthetic fitting. This in turn results in a compromise in quality of life and increased health care expenditures by the Veterans Health Administration. While multiple factors contribute to delayed or failed wound healing, limb perfusion is a known critical component in stump healing. While ankle-brachial index (ABI) and transcutaneous oxygen pressure (TCPO2) measurements can be used to quantify limb perfusion and can assist in determining the need for an amputation, the literature is conflicted as to the utility of these values in predicting amputation stump healing, with no clear association established. Without reliable objective means of predicting the likelihood of healing, the level of amputation is determined clinically by the operating surgeon based on subjective (i.e. visual) assessment of skin and tissue integrity, quality, and perfusion. This study introduces an injectable subcutaneous bio-sensing technology used with an optical analysis data acquisition system that will immediately detect clinically relevant tissue oxygenation tension in a specific anatomic plane. The overarching hypothesis of this study is that accurate real-time measurement of tissue oxygen tension obtained by use of a novel implantable biosensor is a vital component in determining the appropriate level of amputation, promoting fast primary healing of the residual limb thereby providing a path for the veteran to earlier mobility, increased likelihood of prosthetic fitting, and improved function. This study aims to 1) correlate tissue oxygen tension measured by the biosensor 1 cm below the clinically determined amputation level with established clinical endpoints of primary healing of surgical incision/wound, secondary healing of surgical incision/wound requiring local wound care without reoperation, reoperation for wound revision, and reoperation for revision amputation at a more proximal level; 2) establish the reliability and responsiveness of the biosensor in obtaining accurate readings of the tissue oxygen tension when implanted subcutaneously in the lower extremity of human subjects and 3) establish preliminary guidelines for use of tissue oxygen tension in conjunction with covariate risk score for reamputation to preoperatively guide the determination of the most appropriate level of amputation to best predict primary healing of lower extremity amputation stumps, expediting prosthetic fitting and mobility, minimizing complication rates, and decreasing associated costs. Per current standard of care, the amputation level will be determined by the operating surgeon based on clinical judgement of the appearance of the surrounding tissue (skin integrity, amount of edema, proximal extent of infection or chronic ulceration if present, and color of the limb). The level of amputation will not be altered by participation in the study. Two biosensors will be inserted into the subcutaneous tissue of each anatomic angiosome via a sterile 19 Gauge needle 1 cm caudad to the planned incision. Tissue oxygen tension will be recorded from each sensor immediately prior to the start of the surgical procedure and again immediately after inflation of the tourniquet. The surgical amputation procedure will proceed routinely with no alteration in the surgical plan from standard of care. Study follow-up will continue for 3 months after surgery; clinical endpoints at 3 months will be correlated with tissue oxygen tension measured intra-operatively just below the level of amputation.