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Background: In anterior lumbar interbody fusion (ALIF), the use of integrated screws is attractive to surgeons because of the ease of implantation and no additional profile. However, the number and length of screws necessary for safe and stable implantation in various bone densities is not yet fully understood. The current study aims to determine how important both length and number of screws are for stability of ALIFs. Methods: Three bone models with densities of 10, 15, and 20 pounds per cubic foot (PCF) were chosen as surrogates. These were instrumented using the Z-Link lumbar interbody system with either 2, 3, or 4 integrated 4.5 × 20 mm screws or 4.5 × 25 mm screws (Zavation, LLC, Flowood, MS). The bone surrogates were tested with loading conditions resulting in spine extension to measure construct stiffness and peak force. Results: The failure load of the construct was influenced by the length of screws (p=.01) and density of the bone surrogate (p<.01). There was no difference in failure load between using 2 screws and 3 screws (p=.32) or when using four 20 mm screws versus three 25 mm screws (p=.295). Conclusion: In our study, both bone density and length of screws significantly affected the construct's load to failure. In certain cases where a greater number of screws are unable to be implanted, the same stability can potentially be conferred with use of longer screws. Future clinical studies should be performed to test these biomechanical results.
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Introduction: This study aimed to identify demographic, clinical, and operative factors associated with increased postoperative compliance of patient-reported outcome (PRO) assessments following lumbar spine surgery. Methods: A retrospective study of prospectively collected data of 1,680 consecutive adult patients who underwent elective lumbar surgery at a single institution from 2017-2020. Digital assessment questionnaires were used to assess PROs (i.e., VAS-back, VAS-leg, Oswestry Disability Index, Short Form (SF-12) mental & physical health, VR-12 mental and physical, and VR6D scores) and patient compliance, defined as the percentage of questionnaires completed preoperatively, at 3 months and 1 year after surgery. Multivariate logistic regression was used to assess the association between PRO compliance and patient characteristics. Results: A total of 1,680 patients (53.1% male, mean age: 57.7 years) had a mean PRO compliance of 64.7%. Compliance decreased continuously from initial preoperative rates (84.5%) to lower rates at 3 months (54.4%) and 12 months (45.6%), respectively, with 33.2% of patients completing zero assessment questionnaires at 12 months, postoperatively. Factors associated with significantly increased PRO compliance included being employed (preop: odds ratio [OR]=2.58, p=0.002; 3-month postop: OR=1.25, p=0.095; 12-month postop: OR=1.34, p=0.028). Factors associated with decreased compliance included preoperative smoking status (3-month postop: OR=0.63, p=0.029; 12-month postop: OR=0.60, p=0.016). Conclusions: Patients who completed greater than 50% of their PROs demonstrated significantly different rates of being employed compared with those who completed less than 50% throughout 1 year of follow-up. Preoperative smoking status was associated with decreased compliance, whereas a history of employment was associated with increased compliance throughout follow-up. To validate our findings and explore additional parameters that affect postoperative compliance of PROs, further investigation is required.
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INTRODUCTION: The purpose of this systematic review is to identify whether poor nutrition, as defined by the more commonly used markers of low albumin, low transferrin, or low total lymphocyte count (TLC), leads to more postoperative complications. We hypothesized that it may be possible to identify the levels of these laboratory values at which point total joint arthroplasty (TJA) may be ill advised. To this end, we analyzed the available literature regarding links between these three variables on postoperative complications after TJA. METHODS: This systematic review was done in two parts: (1) In the first part, we reviewed the most commonly used malnutrition marker, albumin. (2) In the second part, we reviewed TLC and transferrin. We accessed PubMed, EMBASE, and Cochrane Library using relevant keywords to this study. The biostatistics were visualized using a random-effects forest plot. We compared data from all articles with sufficient data on patients with complications (ie, cases) and patients without complications (ie, noncases) among the two groups, malnourished and normal nutrition, from albumin, transferrin, and TLC data. RESULTS: A meta-analysis of seven large-scale articles detailing the complications of albumin led to an all-cause relative risk increase of 1.93 when operating with hypoalbuminemia. This means that in the studies detailed enough to incorporate in this pooled analysis, operating on elective TJAs with low albumin is associated with a 93% increase in all measured complications. In the largest studies, analysis of transferrin levels for the most common complications revealed a relative risk increase of 2.52 when operating on patients with low transferrin levels. There were not enough subjects to do a biostatistical analysis in articles using TLC as the definition of malnutrition. CONCLUSION: The focus is on the trends rather than absolutes. As shown in Table 1, whether the albumin cutoff for albumin was 3.0 g/dL, 3.5 g/dL, or 3.9 g/dL, the trend remains the same. Because low albumin before TJAs tends to increase complications, it is recommended to incorporate albumin levels in preoperative workups. Many patients with hip and knee arthritis undergo months of conservative management (eg, physical therapy and corticosteroid injections) before considering surgery, and it would be wise to optimize their nutritional status in this period to minimize the risk of perioperative complications. The physician should use these data to provide informed consent of the increased risk to patients planning to undergo TJAs with elevated malnutrition markers. Because this research is retrospective in nature, albumin should be studied prospectively in hypoalbuminemic and normoalbuminemic patients and their postoperative outcomes should be measured. Regarding transferrin and TLC, future research should help elucidate their predictive value and determine the value of preoperatively optimizing them and their effect in mitigating postoperative complications.
