The response of the Military Health System (MHS) to the COVID-19 pandemic: a summary of findings from MHS reviews.

INTRODUCTION: The coronavirus disease 2019 (COVID-19) pandemic caused major disruptions to the US Military Health System (MHS). In this study, we evaluated the MHS response to the pandemic to understand the impact of the pandemic response in a large, national, integrated healthcare system providing care for ~ 9 million beneficiaries. METHODS: We performed a narrative literature review of 16 internal Department of Defense (DoD) reports, including reviews mandated by the US Congress in response to the pandemic. We categorized the findings using the Doctrine, Organization, Training, Materiel, Leadership, Personnel, Facilities, and Policy (DOTMLPF-P) framework developed by the DoD to assess system efficiency and effectiveness. RESULTS: The majority of the findings were in the policy, organization, and personnel categories. Key findings showed that the MHS structure to address surge situations was beneficial during the pandemic response, and the rapid growth of telehealth created the potential impact for improved access to routine and specialized care. However, organizational transition contributed to miscommunication and uneven implementation of policies; disruptions affected clinical training, upskilling, and the supply chain; and staffing shortages contributed to burnout among healthcare workers. CONCLUSION: Given its highly integrated, vertical structure, the MHS was in a better position than many civilian healthcare networks to respond efficiently to the pandemic. However, similar to the US civilian sector, the MHS also experienced delays in care, staffing and materiel challenges, and a rapid switch to telehealth. Lessons regarding the importance of communication and preparation for future public health emergency responses are relevant to civilian healthcare systems responding to COVID-19 and other similar public health crises.

Intraoperative CT for lumbar fusion is not associated with improved short- or long-term complication profiles.

BACKGROUND CONTEXT: The use of intraoperative CT has continued to grow in recent years, as various techniques leverage the promise of improved instrumentation accuracy and the hope for decreased complications. Nonetheless, the literature regarding the short- and long-term complications associated with such techniques remains scant and/or confounded by indication and selection bias. PURPOSE: To use causal inference techniques to determine whether intraoperative CT use is associated with an improved complication profile as compared to conventional radiography for single-level lumbar fusions, an increasingly commonplace application for this technology. STUDY DESIGN/SETTING: Inverse probability weighted retrospective cohort study carried out within a large integrated health care network. PATIENT SAMPLE: Adult patients who underwent surgical treatment of spondylolisthesis via lumbar fusion from January 2016 to December 2021. OUTCOME MEASURES: Our primary outcome was the incidence rate of revision surgery. Our secondary outcome was the incidence of composite 90-day complications (deep and superficial surgical site infection, venous thromboembolic events, and unplanned readmissions). METHODS: Demographics, intraoperative information, and postoperative complications were abstracted from electronic health records. A propensity score was developed utilizing a parsimonious model to account for covariate interaction with our primary predictor, intraoperative imaging technique. This propensity score was utilized in the creation of inverse probability weights to adjust for indication and selection bias. The rate of revisions within 3 years as well as the rate of revisions at any time-point were compared between cohorts using Cox regression analysis. The incidence of composite 90-day complications were compared using negative binomial regression. RESULTS: Our patient population consisted of 583 patients, with 132 who underwent intraoperative CT and 451 who underwent conventional radiographic techniques. There were no significant differences between cohorts following inverse probability weighting. No significant differences were detected in 3-year revision rates (HR, 0.74 [95% CI 0.29, 1.92]; p=.5), overall revision rates (HR, 0.54 [95% CI 0.20, 1.46]; p=.2), or 90-day complications (RC -0.24 [95% CI -1.35, 0.87]; p=.7). CONCLUSIONS: Intraoperative CT use was not associated with an improved complication profile in either the short- or long-term for patients undergoing single-level instrumented fusion. This observed clinical equipoise should be weighed against resource and radiation-related costs when considering intraoperative CT for low complexity fusions.

Projected lifetime cancer risk for patients undergoing spine surgery for isthmic spondylolisthesis.

BACKGROUND CONTEXT: Radiographs, fluoroscopy, and computed tomography (CT) are increasingly utilized in the diagnosis and management of various spine pathologies. Such modalities utilize ionizing radiation, a known cause of carcinogenesis. While the radiation doses such studies confer has been investigated previously, it is less clear how such doses translate to projected cancer risks, which may be a more interpretable metric. PURPOSE: (1) Calculate the lifetime cancer risk and the relative contributions of preference-sensitive selection of imaging modalities associated with the surgical management of a common spine pathology, isthmic spondylolisthesis (IS); (2) Investigate whether the use of intraoperative CT, which is being more pervasively adopted, increases the risk of cancer. STUDY DESIGN/SETTING: Retrospective cross-sectional study carried out within a large integrated health care network. PATIENT SAMPLE: Adult patients who underwent surgical treatment of IS via lumbar fusion from January 2016 through December 2021. OUTCOME MEASURES: (1) Effective radiation dose and lifetime cancer risk associated with each exposure to ionizing radiation; (2) Difference in effective radiation dose (and lifetime cancer risk) among patients who received intraoperative CT compared to other intraoperative imaging techniques. METHODS: Baseline demographics and differences in surgical techniques were characterized. Radiation exposure data were collected from the 2-year period centered on the operative date. Projected risk of cancer from this radiation was calculated utilizing each patient's effective radiation dose in combination with age and sex. Generalized linear modeling was used to adjust for covariates when determining the comparative risk of intraoperative CT as compared to alternative imaging modalities. RESULTS: We included 151 patients in this cohort. The range in calculated cancer risk exclusively from IS management was 1.3-13 cases of cancer per 1,000 patients. During the intraoperative period, CT imaging was found to significantly increase radiation exposure as compared to alternate imaging modalities (adjusted risk difference (ARD) 12.33mSv; IQR 10.04, 14.63mSv; p<.001). For a standardized 40 to 49-year-old female, this projects to an additional 0.72 cases of cancer per 1,000. For the entire 2-year perioperative care episode, intraoperative CT as compared to other intraoperative imaging techniques was not found to increase total ionizing radiation exposure (ARD 9.49mSv; IQR -0.83, 19.81mSv; p=.072). The effect of intraoperative imaging choice was mitigated in part due to preoperative (ARD 13.1mSv, p<.001) and postoperative CTs (ARD 22.7mSv, p<.001). CONCLUSIONS: Preference-sensitive imaging decisions in the treatment of IS impart substantial cancer risk. Important drivers of radiation exposure exist in each phase of care, including intraoperative CT and/or CT scans during the perioperative period. Knowledge of these data warrant re-evaluation of current imaging protocols and suggest a need for the development of radiation-sensitive approaches to perioperative imaging.

The effectiveness of systemic therapies after surgery for metastatic renal cell carcinoma to the spine: a propensity analysis controlling for sarcopenia, frailty, and nutrition.

OBJECTIVE: The effectiveness of starting systemic therapies after surgery for spinal metastases from renal cell carcinoma (RCC) has not been evaluated in randomized controlled trials. Agents that target tyrosine kinases, mammalian target of rapamycin signaling, and immune checkpoints are now commonly used. Variables like sarcopenia, nutritional status, and frailty may impact recovery from spine surgery and are considered when evaluating a patient's candidacy for such treatments. A better understanding of the significance of these variables may help improve patient selection for available treatment options after surgery. The authors used comparative effectiveness methods to study the treatment effect of postoperative systemic therapies (PSTs) on survival. METHODS: Univariable and multivariable Cox regression analyses were performed to determine factors associated with overall survival (OS) in a retrospective cohort of adult patients who underwent spine surgery for metastatic RCC between 2010 and 2019. Propensity score-matched (PSM) analysis and inverse probability weighting (IPW) were performed to determine the treatment effect of PST on OS. To address confounding and minimize bias in estimations, PSM and IPW were adjusted for covariates, including age, sex, frailty, sarcopenia, nutrition, visceral metastases, International Metastatic RCC Database Consortium (IMDC) risk score, and performance status. RESULTS: In total, 88 patients (73.9% male; median age 62 years, range 29-84 years) were identified; 49 patients (55.7%) had an intermediate IMDC risk, and 29 (33.0%) had a poor IMDC risk. The median follow-up was 17 months (range 1-104 months) during which 57 patients (64.7%) died. Poor IMDC risk (HR 3.2 [95% CI 1.08-9.3]), baseline performance status (Eastern Cooperative Oncology Group score 3 or 4; HR 2.7 [95% CI 1.5-4.7]), and nutrition (prognostic nutritional index [PNI] first tertile, PNI < 40.74; HR 2.69 [95% CI 1.42-5.1]) were associated with worse OS. Sarcopenia and frailty were not significantly associated with poor survival. PST was associated with prolonged OS, demonstrated by similar effects from multivariable Cox analysis (HR 0.55 [95% CI 0.30-1.00]), PSM (HR 0.53 [95% CI 0.29-0.93]), IPW (HR 0.47 [95% CI 0.24-0.94]), and comparable confidence intervals. The median survival for those receiving PST was 28 (95% CI 19-43) months versus 12 (95% CI 4-37) months for those who only had surgery (log-rank p = 0.027). CONCLUSIONS: This comparative analysis demonstrated that PST is associated with improved survival in specific cohorts with metastatic spinal RCC after adjusting for frailty, sarcopenia, and malnutrition. The marked differences in survival should be taken into consideration when planning for surgery.

A comparison of cell salvage strategies in posterior spinal fusion for adolescent idiopathic scoliosis.

STUDY DESIGN: Retrospective case-control study. OBJECTIVE: To compare the efficacy of 3 blood management strategies in patients undergoing posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) in reducing donor blood transfusion. SUMMARY OF BACKGROUND DATA: Although intraoperative cell salvage and predonated banked blood may be effective in reducing donor blood transfusion in the perioperative period, the optimal blood management strategy is unclear. A combined cell salvage strategy holds several potential advantages but has not yet been investigated. METHODS: Patients who underwent isolated PSF for AIS (n=167) were subdivided into 3 groups by perioperative blood management strategy: (1) intraoperative retransfusion of shed blood (cell saver) and predonated autologous banked blood (n=51); (2) cell saver alone (n=33); and (3) combined cell saver and postoperative collection and retransfusion of drained blood (Retransfusion drain) (n=83). Data collected included age, sex, diagnosis, body weight, number of levels fused, operative time, intraoperative and postoperative blood loss and retransfusion, preoperative and postoperative (72 h) hemoglobin and hematocrit (Hct), and amount of autologous and donor blood transfused in the perioperative period. RESULTS: Fewer patients in the cell saver and predonated blood (3.9%) and cell saver and retransfusion drain (1.2%) groups received donor transfusions than did those managed with cell saver alone (33%). There was no significant difference in the donor transfusion rate between cell saver/predonated blood and retransfusion groups. Mean postoperative Hct (72 h) was higher in the retransfusion group 3 than in the other 2 (group 3: 29.3%, group 1: 25.4%, group 2: 26.1%). There was no significant difference in the mean change in hemoglobin and Hct after surgery between the 3 groups. CONCLUSIONS: The present study demonstrates the efficacy of a combined intraoperative and postoperative cell salvage strategy in PSF for AIS, significantly reducing perioperative donor blood transfusions, maintaining physiological Hct, and conserving blood bank resources.

Effects of supplemental oxygen and hyperbaric oxygen on tendon healing in a rat model.

Systemic supplemental oxygen therapy (SOT) and hyperbaric oxygen therapy (HBOT) have been shown to positively impact wound healing. The purpose of this study was to evaluate the effects of SOT and HBOT on tendon healing in a rat tendon model. The right patellar tendon of 90 male Sprague-Dawley rats was completely sectioned. Animals were randomized to receive HBOT, SOT, or room air therapy. Animals were sacrificed at 3- and 6-weeks postoperatively. The ultimate tensile strength in axial extension was compared between groups. Statistical significance was calculated using the Student's t-test. The SOT group exhibited the highest tensile strength at both time-points, although HBOT was the only treatment that exhibited a statistically significant increase in tensile strength between time-periods (p = 0.006). There was no statistical difference in ultimate tensile strength when the three groups were compared at the 3- or 6-week time-points. Results presented here cannot support the premise that intermittent HBOT or SOT significantly increases the healing of tendon repairs.