Sacropelvic Fixation with Porous Fusion/Fixation Screws: A Technical Note and Retrospective Review.

OBJECTIVE: The goal of this study was to analyze our initial experience using a novel porous fusion/fixation screw (PFFS) for pelvic fixation, and to determine our rate of screw malposition requiring intraoperative repositioning. METHODS: We reviewed 83 consecutive patients who underwent sacropelvic fixation with PFFS at our institution from 6/1/2022-6/30/2023 using intraoperative CT-based computer-assisted navigation (CAN) via an open posterior approach. Following PFFS insertion, intraoperative CT scans were obtained to assess screw positioning. Demographic data was collected, and operative reports and patient images were reviewed to determine what implants were used and if any PFFS required repositioning. RESULTS: 74 patients (26M:48F) were included, and 57 (77.0%) had a prior sacroiliac joint or lumbar spine surgery. A stacked screw configuration was used in 62/74 cases (83.8%). A total of 235 PFFS were used and six (2.6%) were malpositioned. Of 88 cephalic screws placed in stacked configuration, 4 were malpositioned (4.5%); and 1/123 caudal screws were malpositioned (0.8%). One of 24 SAI screws placed in a stand-alone configuration was malpositioned (4.2%). Malpositions included four medial, one lateral, and one inferior; and all were revised intraoperatively without major sequela. CONCLUSIONS: Although PFFS are larger than traditional sacropelvic fixation screws, stacked SAI instrumentation can be done safely with CAN. We found a low malposition rate in our initial series of patients, the majority being the cephalad screw in a stacked configuration. This isn't surprising, as these are placed after the caudal screws which reduces the available corridor size and increases the placement difficulty.

Spine surgeon versus AI algorithm full-length radiographic measurements: a validation study of complex adult spinal deformity patients.

INTRODUCTION: Spinal measurements play an integral role in surgical planning for a variety of spine procedures. Full-length imaging eliminates distortions that can occur with stitched images. However, these images take radiologists significantly longer to read than conventional radiographs. Artificial intelligence (AI) image analysis software that can make such measurements quickly and reliably would be advantageous to surgeons, radiologists, and the entire health system. MATERIALS AND METHODS: Institutional Review Board approval was obtained for this study. Preoperative full-length standing anterior-posterior and lateral radiographs of patients that were previously measured by fellowship-trained spine surgeons at our institution were obtained. The measurements included lumbar lordosis (LL), greatest coronal Cobb angle (GCC), pelvic incidence (PI), coronal balance (CB), and T1-pelvic angle (T1PA). Inter-rater intra-class correlation (ICC) values were calculated based on an overlapping sample of 10 patients measured by surgeons. Full-length standing radiographs of an additional 100 patients were provided for AI software training. The AI algorithm then measured the radiographs and ICC values were calculated. RESULTS: ICC values for inter-rater reliability between surgeons were excellent and calculated to 0.97 for LL (95% CI 0.88-0.99), 0.78 (0.33-0.94) for GCC, 0.86 (0.55-0.96) for PI, 0.99 for CB (0.93-0.99), and 0.95 for T1PA (0.82-0.99). The algorithm computed the five selected parameters with ICC values between 0.70 and 0.94, indicating excellent reliability. Exemplary for the comparison of AI and surgeons, the ICC for LL was 0.88 (95% CI 0.83-0.92) and 0.93 for CB (0.90-0.95). GCC, PI, and T1PA could be determined with ICC values of 0.81 (0.69-0.87), 0.70 (0.60-0.78), and 0.94 (0.91-0.96) respectively. CONCLUSIONS: The AI algorithm presented here demonstrates excellent reliability for most of the parameters and good reliability for PI, with ICC values corresponding to measurements conducted by experienced surgeons. In future, it may facilitate the analysis of large data sets and aid physicians in diagnostics, pre-operative planning, and post-operative quality control.

Risk Factors for Postoperative Ileus in Patients Undergoing Spine Surgery.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVES: Postoperative ileus (POI) is a common complication following elective spinal surgeries. The aim of this study was to determine the incidence of POI and identify demographic and surgical risk factors for developing POI after elective instrumented fusion of the thoracolumbar spine. METHODS: The University of Utah Institutional Review Board (IRB) approved this retrospective study. The study does not require informed consent given the data reviewed was deidentified and collected in accordance with the institution's standard of care. A designated IRB committee determined that study is exempt under exemption category 7. IRB approval number 00069703. Patients undergoing instrumented thoracolumbar fusion for one or more levels were retrospectively identified from an internal spine surgery database. Cases performed for trauma, infection, or tumors were excluded. Demographics, medical comorbidities, surgical variables, and opioid medication administration (morphine milligram equivalents, MME) were abstracted from the electronic medical record. Univariate analysis was used to identify variables associated with POI. These variables were then tested for independent association with POI using multivariate logistic regression. RESULTS: 418 patients were included in the current study. The incidence of POI was 9.3% in this cohort. There was no significant relationship between development of POI and patient age, gender, BMI, diabetes mellitus, thyroid dysfunction, lung disease, CKD, GERD, smoking status, alcohol abuse, anemia, or prior abdominal surgery. Univariate analysis demonstrated significant association between POI and fusion ≥7 levels compared to fusions of fewer levels (P = .001), as well as intraoperative sufentanil compared to other opioids (35.9% vs 20.1%, P = .02). POI was not significantly associated with total intraoperative MME, approach, use of interbody cage, or osteotomy. Multivariate logistic regression confirmed total 24-hour postoperative MME as an independent risk factor for POI (OR 1.004, P = .04), however, intraoperative sufentanil administration was not an independent risk factor for POI when controlling for other variables. CONCLUSIONS: This retrospective cohort study demonstrates that greater postoperative MME is an independent risk factor for POI after thoracolumbar spine fusion when accounting for demographic, medical, and surgical variables with multiple logistic regression. Prospective studies are warranted to evaluate clinical measures to decrease the risk of POI among patients undergoing instrumented thoracolumbar spinal fusions.

Conditionally Essential Amino Acid Supplementation Reduces Postoperative Complications and Muscle Wasting After Fracture Fixation: A Randomized Controlled Trial.

BACKGROUND: Postoperative complications and substantial loss of physical function are common after musculoskeletal trauma. We conducted a prospective randomized controlled trial to assess the impact of conditionally essential amino acid (CEAA) supplementation on complications and skeletal muscle mass in adults after operative fixation of acute fractures. METHODS: Adults who sustained pelvic and extremity fractures that were indicated for operative fixation at a level-I trauma center were enrolled. The subjects were stratified based on injury characteristics (open fractures and/or polytrauma, fragility fractures, isolated injuries) and randomized to standard nutrition (control group) or oral CEAA supplementation twice daily for 2 weeks. Body composition (fat-free mass [FFM]) was measured at baseline and at 6 and 12 weeks postoperatively. Complications were prospectively collected. An intention-to-treat analysis was performed. The relative risk (RR) of complications for the control group relative to the CEAA group was determined, and linear mixed-effects models were used to model the relationship between CEAA supplementation and changes in FFM. RESULTS: Four hundred subjects (control group: 200; CEAA group: 200) were enrolled. The CEAA group had significantly lower overall complications than the control group (30.5% vs. 43.8%; adjusted RR = 0.71; 95% confidence interval [CI] = 0.55 to 0.92; p = 0.008). The FFM decreased significantly at 6 weeks in the control subjects (-0.9 kg, p = 0.0205), whereas the FFM was maintained at 6 weeks in the CEAA subjects (-0.33 kg, p = 0.3606). This difference in FFM was not seen at subsequent time points. CONCLUSIONS: Our results indicate that CEAA supplementation has a protective effect against common complications and early skeletal muscle wasting after operative fixation of extremity and pelvic fractures. Given the potential benefits of this inexpensive, low-risk intervention, multicenter prospective studies in focused trauma populations are warranted. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Multiple Points of Pelvic Fixation: Stacked S2-Alar-Iliac Screws (S2AI) or Concurrent S2AI and Open Sacroiliac Joint Fusion with Triangular Titanium Rod.

Sacropelvic fixation is a continually evolving technique in the treatment of adult spinal deformity. The 2 most widely utilized techniques are iliac screw fixation and S2-alar-iliac (S2AI) screw fixation1-3. The use of these techniques at the base of long fusion constructs, with the goal of providing a solid base to maintain surgical correction, has improved fusion rates and decreased rates of revision4. Description: The procedure is performed with the patient under general anesthesia in the prone position and with use of 3D computer navigation based on intraoperative cone-beam computed tomography (CT) imaging. A standard open posterior approach with a midline incision and subperiosteal exposure of the proximal spine and sacrum is performed. Standard S2AI screw placement is performed. The S2AI starting point is on the dorsal sacrum 2 to 3 mm above the S2 foramen, aiming as caudal as possible in the teardrop. A navigated awl is utilized to establish the screw trajectory, passing through the sacrum, across the sacroiliac (SI) joint, and into the ilium. The track is serially tapped with use of navigated taps, 6.5 mm followed by 9.5 mm, under power. The screw is then placed under power with use of a navigated screwdriver.Proper placement of the caudal implant is vital as it allows for ample room for subsequent instrumentation. The additional point of pelvic fixation can be an S2AI screw or a triangular titanium rod (TTR). This additional implant is placed cephalad to the trajectory of the S2AI screw. A starting point 2 to 3 mm proximal to the S2AI screw tulip head on the sacral ala provides enough clearance and also helps to keep the implant low enough in the teardrop that it is likely to stay within bone. More proximal starting points should be avoided as they will result in a cephalad breach.For procedures with an additional point of pelvic fixation, the cephalad S2AI screw can be placed using the previously described method. For placement of the TTR, the starting point is marked with a burr. A navigated drill guide is utilized to first pass a drill bit to create a pilot hole, followed by a guide pin proximal to the S2AI screw in the teardrop. Drilling the tip of the guide pin into the distal, lateral iliac cortex prevents pin backout during the subsequent steps. A cannulated drill is then passed over the guide pin, traveling from the sacral ala and breaching the SI joint into the pelvis. A navigated broach is then utilized to create a track for the implant. The flat side of the triangular broach is turned toward the S2AI screw in order to help the implant sit as close as possible to the screw and to allow the implant to be as low as possible in the teardrop. The navigation system is utilized to choose the maximum possible implant length. The TTR is then passed over the guide pin and impacted to the appropriate depth. Multiplanar post-placement fluoroscopic images and an additional intraoperative CT scan of the pelvis are obtained to verify instrumentation position. Alternatives: The use of spinopelvic fixation in long constructs is widely accepted, and various techniques have been described in the past1. Alternatives to stacked S2AI screws or S2AI with TTR for SI joint fusion include traditional iliac screw fixation with offset connectors, modified iliac fixation, sacral fixation alone, and single S2AI screw fixation. Rationale: The lumbosacral junction is the foundation of long spinal constructs and is known to be a point of high mechanical strain5-7. Although pelvic instrumentation has been utilized to increase construct stiffness and fusion rates, pelvic fixation failure is frequently reported8,9. At our institution, we identified a 5% acute pelvic fixation failure rate over an 18-month period10. In a subsequent multicenter retrospective series, a similar 5% acute pelvic fixation failure rate was also reported11. In response to these findings, our institution changed its pelvic fixation strategies to incorporate multiple points of pelvic fixation. From our experience, utilization of multiple pelvic fixation points has decreased acute failure. In addition to preventing instrumentation failure, S2AI screws are lower-profile, which decreases the complication of implant prominence associated with traditional iliac screws. S2AI screw heads are also more in line with the pedicle screw heads, which decreases the need for excessive rod bending and connectors.The use of the techniques has been described in case reports and imaging studies12-14, but until now has not been visually represented. Here, we provide technical and visual presentation of the placement of stacked S2AI screws or open SI joint fusion with a TTR above an S2AI screw. Expected Outcomes: Pelvic fixation provides increased construct stiffness compared with sacral fixation alone15-17 and has shown better rates of fusion4. However, failure rates of up to 35%8,9 have been reported, and our own institution identified a 5% acute pelvic fixation failure rate10. In response to this, the multiple pelvic fixation strategy (stacked S2AI screws or S2AI and TTR for SI joint fusion) has been more widely utilized. In our experience utilizing multiple points of pelvic fixation, we have noticed a decreased rate of pelvic fixation failure and are in the process of reporting these findings18,19. Important Tips: The initial trajectory of the caudal S2AI screw needs to be as low as possible within the teardrop, just proximal to the sciatic notch.The starting point for the cephalad implant should be 2 to 3 mm proximal to the S2AI screw tulip head. This placement provides enough clearance and helps to contain the implant in bone.More proximal starting points may result in cephalad breach of the TTR.The use of a reverse-threaded Kirschner wire helps to prevent pin backout while drilling and broaching for TTR placement.If malpositioning of the TTR is found on imaging, removal and redirection is technically feasible. Acronyms and Abbreviations: S2AI = S2-alar-iliacTTR = triangular titanium rodCT = computed tomographyAP = anteroposteriorOR = operating roomSI = sacroiliacDRMAS = dual rod multi-axial screwK-wire = Kirschner wireDVT = deep vein thrombosisPE = pulmonary embolism.

Asymptomatic Pre-Operative COVID-19 Screening for Essential and Elective Surgeries: Early Results of Universal Screening at a Midwestern Academic Medical Center.

BACKGROUND: During the novel Coronavirus 2019 (COVID-19) worldwide pandemic, viral testing has largely focused on patients presenting with fever and respiratory symptoms. Although Centers for Disease Control has reported 1,551,095 cases in the United States as of May 21, 2020, asymptomatic infection rates remain unknown within the U.S., especially in geographically disparate regions. METHODS: On April 7, 2020 our hospital established universal SARS-CoV-2 screening using RT-PCR RNA detection from nasopharyngeal swabs from asymptomatic patients prior to essential and elective surgeries. This study included 1,997 asymptomatic patients undergoing surgical procedures and 1,797 admitted for medical management at a Midwestern academic hospital between April 7, 2020 and May 21, 2020. RESULTS: As of May 21, asymptomatic testing for SARS-CoV-2 infection had been completed for 1,997 surgical patients and 1,797 non-surgical patients. Initial testing was positive in 26 patients, with an additional four positive tests occurring during repeat testing when greater than 48 hours had elapsed since initial testing. Overall asymptomatic infection rate was 0.79%. Asymptomatic infection rate was significantly lower in surgical patients (0.35% vs. 1.28%, p=0.001). Surgical patients tended to be older than non-surgical patients, although this was not statistically significant (51, IQR 27-65 vsx 46, IQR 28-64, p=0.057). Orthopedic surgery patients were significantly younger than those from other surgical services (42 vs. 53 yrs, p<0.001), however orthopedic and non-orthopedic surgical patients had similar asymptomatic infection rates (0.70% vs. 0.25%, p=0.173). CONCLUSION: Among asymptomatic patients tested at a Midwestern academic medical center, 0.79% were infected with SARS-CoV-2 virus. These findings will help guide screening protocols at medical centers while providing essential and elective procedures during the COVID-19 pandemic. While the asymptomatic infection rate was low, this data substantiates the threat of asymptomatic infections and potential for community viral spread. These results may not be generalizable to large urban population centers or areas with high concentrations of COVID-19, each region must use available data to evaluate the risk-benefit ratio of universal testing vs universal contact precautions.Level of Evidence: IV.

Sarcopenia is associated with increased mortality but not complications following resection and reconstruction of sarcoma of the extremities.

BACKGROUND AND OBJECTIVES: Evidence regarding the impact of sarcopenia on operative outcomes in patients with sarcoma is lacking. We evaluated the relationship between sarcopenia and postoperative complications or mortality among patients undergoing tumor excision and reconstruction. ​ METHODS: We retrospectively reviewed 145 patients treated with tumor excision and limb reconstruction for sarcoma of the extremities. Sarcopenia was defined as psoas index (PI) < 5.45 cm2 /m2 for men and <3.85 cm2 /m2 for women from preoperative axial CT. Regression analyses were used to assess the association between postoperative complications or mortality with PI, age, gender, race, body mass index, tumor histology, grade, depth, location, size, and neoadjuvant/adjuvant therapy. RESULTS: There were 101 soft tissue tumors and 44 primary bone tumors. Sarcopenia was present in 38 patients (26%). Sarcopenic patients were older (median age: 72 vs 59 years, P = .0010) and had larger tumors (86.5%, >5 cm vs 77.7%, P = .023). Seventy-three patients experienced complications (51%) and 18 patients died within 1 year. Sarcopenia and metastatic disease were associated with increased 12-month mortality (hazard ratio [HR] = 6.68, P < .001; HR: 8.51, P < .001, respectively) but not complications (HR 1.45, P = .155, odds ratio, 1.32, P = .426, respectively). CONCLUSIONS: Sarcopenia and metastatic disease were independently associated with postoperative mortality but no complications following surgery.

Associations between evaporative cooling and dust-mite allergens, endotoxins, and ß-(1 → 3)-d-glucans in house dust: A study of low-income homes.

Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and ß-(1 â†’ 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P < .01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P = .03). ß-(1 â†’ 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P < .01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations.

Overlapping Surgery in Primary Total Knee Arthroplasty: Are 6-Week Complications Worse than Single Operating Room Scheduling?

Background: Overlapping surgery is common in high-volume total knee arthroplasty (TKA) practices and has come under recent scrutiny in the press. The aim of this study was to evaluate differences in 6-week clinical and radiographic outcomes for primary TKA patients between single and overlapping operating room (OR) days. Methods: We retrospectively reviewed individual patient records of a consecutive series of primary TKAs with complete 6-week follow-up performed by a single academic surgeon between 2008-2016 (N= 452). Patients were stratified by single vs. overlapping OR days. 177 patients (39%) had an overlapping surgery. Age, body mass index (BMI), Charlson Comorbidity Index (CCI) and American Society of Anesthesiologists (ASA) class were recorded to assess for confounding variables. Outcomes included anesthesia time, 6-week readmission, unplanned return to OR, medical and surgical complication, and 6-week radiographic alignment. Results: There were no significant differences in anesthesiology time (165.5 vs 164.5 min, p=0.85), medical or surgical complication rates (10.5% vs 6.2%, p=0.11), 6-week readmissions (4.4% vs 1.7%, p=0.12), or return to OR (1.8% vs 1.7%, p=1.00) before or after adjusting for age, BMI, gender, ASA and CCI. There was no difference between overlapping and single OR cohorts in rate of neutral coronal alignment (2°-8° valgus) (98.3% vs 98.9%, respectively, p=0.68) or presence of periprosthetic lucency (p=0.43). Conclusions: This study demonstrates no differences in 6-week clinical or radiographic outcomes between patients undergoing primary TKA on single versus overlapping OR days. These results support the safe practice of overlapping surgical scheduling in high-volume primary TKA centers.Level of Evidence: III.

What Are the Costs of Cervical Radiculopathy Prior to Surgical Treatment?

STUDY DESIGN: Retrospective, observational study. OBJECTIVE: To examine the costs associated with nonoperative management (diagnosis and treatment) of cervical radiculopathy in the year prior to anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: While the costs of operative treatment have been previously described, less is known about nonoperative management costs of cervical radiculopathy leading up to surgery. METHODS: The Humana claims dataset (2007-2015) was queried to identify adult patients with cervical radiculopathy that underwent ACDF. Outcome endpoint was assessment of cumulative and per-capita costs for nonoperative diagnostic (x-rays, computed tomographic [CT], magnetic resonance imaging [MRI], electromyogram/nerve conduction studies [EMG/NCS]) and treatment modalities (injections, physical therapy [PT], braces, medications, chiropractic services) in the year preceding surgical intervention. RESULTS: Overall 12,514 patients (52% female) with cervical radiculopathy underwent ACDF. Cumulative costs and per-capita costs for nonoperative management, during the year prior to ACDF was $14.3 million and $1143, respectively. All patients underwent at least one diagnostic test (MRI: 86.7%; x-ray: 57.5%; CT: 35.2%) while 73.3% patients received a nonoperative treatment. Diagnostic testing comprised of over 62% of total nonoperative costs ($8.9 million) with MRI constituting the highest total relative spend ($5.3 million; per-capita: $489) followed by CT ($2.6 million; per-capita: $606), x-rays ($0.54 million; per-capita: $76), and EMG/NCS ($0.39 million; per-capita: $467). Conservative treatments comprised of 37.7% of the total nonoperative costs ($5.4 million) with injections costs constituting the highest relative spend ($3.01 million; per-capita: $988) followed by PT ($1.13 million; per-capita: $510) and medications (narcotics: $0.51 million, per-capita $101; gabapentin: $0.21 million, per-capita $93; NSAIDs: 0.107 million, per-capita $47), bracing ($0.25 million; per-capita: $193), and chiropractic services ($0.137 million; per-capita: $193). CONCLUSION: The study quantifies the cumulative and per-capital costs incurred 1-year prior to ACDF in patients with cervical radiculopathy for nonoperative diagnostic and treatment modalities. Approximately two-thirds of the costs associated with cervical radiculopathy are from diagnostic modalities. As institutions begin entering into bundled payments for cervical spine disease, understanding condition specific costs is a critical first step. LEVEL OF EVIDENCE: 3.

Preoperative Chronic Opioid Therapy Negatively Impacts Long-term Outcomes Following Cervical Fusion Surgery.

STUDY DESIGN: Retrospective, observational. OBJECTIVE: The aim of this study was to define the impact of preoperative chronic opioid therapy (COT) on outcomes following cervical spine fusions. SUMMARY OF BACKGROUND DATA: Opioid therapy is a commonly practiced method to control acute postoperative pain. However, concerns exist relating to use of prescription opioids, including inherent risk of abuse, tolerance, and inferior outcomes following major surgery. METHODS: A commercial dataset was queried from 2007 to 2015 for patients undergoing primary cervical spine arthrodesis [ICD-9 codes 81.01-81.03]. Primary outcome measures were 1-year and 2-year reoperation rates, emergency department (ED) visits, adverse events, and prolonged postoperative opioid use. Secondary outcomes included short-term outcomes including 90-day complications (cardiac, renal, neurologic, infectious, etc.). COT was defined as a history of opioid prescription filling within 3 months before surgery and was the primary exposure variable of interest. Generalized linear models investigated the association of preoperative COT on primary/secondary endpoints following risk-adjustment. RESULTS: Overall, 20,730 patients (51.3% female; 85.9% >50 years) underwent primary cervical spine arthrodesis. Of these, 10,539 (n = 50.8%) met criteria for COT. Postoperatively, 75.3% and 29.8% remained on opioids at 3 months and 1 year. Multivariable models identified an association between COT and an increased risk of 90-day ED visit [odds ratio (OR): 1.25; P < 0.001] and wound complications (OR: 1.24; P = 0.036). At 1 year, COT was strongly associated with reoperations (OR: 1.17; P = 0.043), ED visits (OR: 1.31; P < 0.001), and adverse events including wound complications (OR: 1.32; P < 0.001), infections (OR: 1.34; P = 0.042), constipation (OR: 1.11; P = 0.032), neurological complications (OR: 1.44; P = 0.01), acute renal failure (OR: 1.24; P = 0.004), and venous thromboembolism (OR: 1.20; P = 0.008). At 2 years, COT remained a significant risk factor for additional long-term negative outcomes such as reoperations, including adjacent segment disc disease (OR: 1.21; P = 0.005), ED visits (OR: 1.32; P < 0.001), and other adverse events. Preoperative COT was associated with prolonged postoperative narcotic use at 3 months (OR: 1.30; P < 0.001), 1 year (OR: 5.17; P < 0.001), and at 2 years (OR: 5.75; P < 0.001) after cervical arthrodesis. CONCLUSION: Preoperative COT is a modifiable risk factor that is strongly associated with prolonged postoperative opioid use. In addition, COT was associated with inferior short-term and long-term outcomes after cervical spine fusion. LEVEL OF EVIDENCE: 3.

Perioperative nutrition assessment in musculoskeletal trauma patients: Dietitian evaluation is superior to serum chemistries or modified screening questionnaire for risk stratification.

INTRODUCTION: Malnutrition is a potentially modifiable risk factor associated with increased hospital charges, major wound complication, and fracture non-union after orthopaedic surgery. The goal of this study was to examine the relationship between three nutrition screening tools and postoperative complications in patients undergoing acute fracture fixation. METHODS: Patients aged 18 or older undergoing acute operative fracture fixation at a Level I academic trauma center were screened upon admission using a malnutrition screening questionnaire (MSQ), and classified as low-, moderate- or high risk. Patients at moderate-to-high risk were assessed for clinical malnutrition by dietitian. Serum albumin, transferrin, total lymphocyte count, and 25(OH) Vitamin D were measured preoperatively. Primary outcome measures included twelve-month postoperative surgical and medical complications obtained by retrospective chart review. RESULTS: Of 373 patients, 17% were moderate-to-high risk of malnutrition by MSQ. Clinical malnutrition was diagnosed by dietitian in 4.3% of patients assessed. Nearly half of all subjects had deficiency in one or more serum biomarkers. Cost of biomarker assays was $624 per patient. Medical or surgical complications occurred in 19% of patients. Dietitian diagnosed malnutrition (clinical malnutrition) was the strongest predictor of complication (OR 3.49, p = 0.017). Hypoalbuminemia was also associated with increased complication risk (OR 1.79, p = 0.045). MSQ score was not correlated with postoperative complication. CONCLUSIONS: Among the examined malnutrition screening tools, clinical malnutrition had the strongest association with postoperative complication. Hypoalbuminemia was associated with increased odds of complication, however there was a large false positive rate with all tested serum chemistries and high associated hospital charges compared to dietitian assessment. MSQ was a poor predictor of malnutrition and clinical outcome. Dietetic assessment is advised for orthopaedic trauma patients.

Preparing for Bundled Payments in Cervical Spine Surgery: Do We Understand the Influence of Patient, Hospital, and Procedural Factors on the Cost and Length of Stay?

STUDY DESIGN: Retrospective, observational study. OBJECTIVE: To examine the influence of patient, hospital, and procedural characteristics on hospital costs and length hospital of stay (LOS). SUMMARY OF BACKGROUND DATA: Successful bundled payment agreements require management of financial risk. Participating institutions must understand potential cost input before entering into these episodes-of-care payment contracts. Elective anterior cervical discectomy and fusion (ACDF) has become a popular target for early bundles given its frequency and predictability. METHODS: A national discharge database was queried to identify adult patients undergoing elective ACDF. Using generalized linear models, the impact of each patient, hospital, and procedures characteristic on hospitalization costs and the LOS was estimated. RESULTS: In 2011, 134,088 patients underwent ACDF in the United States. Of these 31.6% had no comorbidities, whereas 18.7% had three or more. The most common conditions included hypertension (44.4%), renal disease (15.9%), and depression (14.7%). Mean hospital costs after ACDF was $18,622 and mean hospital LOS was 1.7 days. With incremental comorbidities, both hospital costs and LOS increased. Both marginal costs and LOS rose with inpatient death (+$17,181, +2.0 days), patients with recent weight loss (+$8351, +1.24 days), metastatic cancer (+$6129 +0.80 days), electrolyte disturbances (+$4175 +0.8 days), pulmonary-circulatory disorders (+$4065, +0.6 days), and coagulopathies (+$3467, +0.58 days). Costs and LOS were highest with the following procedures: addition of a posterior fusion/instrumentation ($+11,189, +0.9 days), revision anterior surgery (+$3465, +0.3 days), and fusion of more than three levels (+$3251, +0.2 days). Patients treated in the West had the highest costs (+$9300, +0.3 days). All P values were less than 0.05. CONCLUSION: Hospital costs and LOS after ACDF rise with increasing patient comorbidities. Stakeholders entering into bundled payments should be aware of that certain patient, hospital, and procedure characteristics will consume greater resources. LEVEL OF EVIDENCE: 3.

Bone Mineral Density T-Scores Derived from CT Attenuation Numbers (Hounsfield Units): Clinical Utility and Correlation with Dual-energy X-ray Absorptiometry.

Background: Clinical computed tomography (CT) studies performed for other indications can be used to opportunistically assess vertebral bone without additional radiation or cost. Reference values for young women are needed to evaluate diagnostic accuracy and track changes in CT bone mineral density values across the lifespan. The purpose of this study was to determine reference values for lumbar trabecular CT attenuation (Hounsfield units [HU]) and determine the diagnostic accuracy of HU T-scores (T-scoreHU) for identifying individuals with osteoporosis. Methods: We performed a retrospective single-center cohort study of patients undergoing CT of the lumbar spine. Reference values for lumbar spine Hounsfield units were determined from a reference sample of 190 young women aged 20-30 years undergoing CT scan of the lumbar spine. A separate sample of 252 older subjects undergoing CT and dual-energy X-ray absorptiometry (DXA) within a 6-month period that served as a validation cohort. Osteoporosis was defined by T-scoreDXA ≤ -2.5. Reference values were determined for lumbar HU from L1 to L4 from the reference cohort (24.0 ± 2.9 years). T-scoreHU was calculated in the validation cohort (58.9 ± 7.5 yrs). Receiver operating characteristic (ROC) curves were used to assess sensitivity and specificity of T-scoreHU for this task. Results: Reference group HU ranged from 227 ± 42 at L3 to 236 ± 42 at L1 (P < 0.001). Validation group T-scoreDXA was -0.7 ± 1.5 and -0.9 ± 1.2 at lumbar and femoral sites respectively. Mean T-scoreHU was -2.3. T-scoreHU of -3.0, corresponding to 110 HU, was 48% sensitive and 91% specific for osteoporosis in the validation group. ROC area under the curve ranged from 0.825 to 0.853 depending on lumbar level assessed. Conclusions: Although lumbar trabecular HU T-scores are lower than DXA T-scores, thresholds can be selected to achieve high sensitivity and specificity when screening for osteoporosis. Patients with a lumbar T-scoreHU ≤ -3.0 should be referred for additional evaluation. Further research into HU T-scores and clinical correlates may also provide a tool to assess changes in vertebral bone and the relationship to fracture risk across the lifespan.

Opioid Utilization Following Lumbar Arthrodesis: Trends and Factors Associated With Long-term Use.

STUDY DESIGN: A retrospective, observational cohort study. OBJECTIVE: In patients undergoing lumbar spine arthrodesis, we sought to establish perioperative trends in chronic versus naive opioid users (OUs) and identify modifiable risk factors associated with prolonged consumption. SUMMARY OF BACKGROUND DATA: The morbidity associated with excessive opioid use for chronic conditions continues to climb and has been identified as a national epidemic. Limiting excessive perioperative opioid use after procedures such as lumbar fusion remains a national health strategy. METHODS: A national commercial claims dataset (2007-2015) was queried for all patients undergoing anterior lumbar interbody fusion (ALIF) and/or lumbar [posterior/transforaminal lumbar interbody fusion (P/TLIF) or posterolateral fusion (PLF)] spinal fusion procedures. Patients were labeled as either an OU (prescription within 3 months pre-surgery) or opioid naive (ON, no prescription). Rates of opioid use were evaluated preoperatively for OU, and longitudinally tracked up to 1-year postoperatively for both OU and ON. Multivariable regression techniques investigated factors associated with opioid use at 1-year following surgery. In addition, a clinical calculator (app) was created to predict 1-year narcotic use. RESULTS: Overall, 26,553 patients (OU: 58.3%) underwent lumbar surgery (ALIF: 8.5%; P/TLIF: 43.8%; PLF: 41.5%; ALIF+PLF: 6.2%). At 1-month postop, 60.2% ON and 82.9% OUs had a filled opioid prescription. At 3 months, prescription rates declined significantly to 13.9% in ON versus 53.8% in OUs, while plateauing at 6 to 12-month postoperative period (ON: 8.4-9.6%; OU: 42.1-45.3%). At 1 year, significantly higher narcotic prescription filling rates were observed in OUs than in ON (42.4% vs. 8.6%; P < 0.001). Preoperative opioid use was the strongest driver of 1-year narcotic use following ALIF [odds ratio (OR): 7.86; P < 0.001], P/TLIFs (OR: 4.62; P < 0.001), or PLF (OR: 7.18; P < 0.001). CONCLUSION: Approximately one-third patients chronically use opioids before lumbar arthrodesis and nearly half of the pre-op OUs will continue to use at 1 year. Our findings serve as a baseline in identifying patients at risk for chronic use and alter surgeons to work toward discontinuation of opioids before lumbar spinal surgery. LEVEL OF EVIDENCE: 3.

Opioid use following cervical spine surgery: trends and factors associated with long-term use.

BACKGROUND CONTEXT: Limited or no data exist evaluating risk factors associated with prolonged opioid use following cervical arthrodesis. PURPOSE: The objectives of this study were to assess trends in postoperative narcotic use among preoperative opioid users (OUs) versus non-opioid users (NOUs) and to identify factors associated with postoperative narcotic use at 1 year following cervical arthrodesis. STUDY DESIGN/SETTING: This is a retrospective observational study. PATIENT SAMPLE: The patient sample included 17,391 patients (OU: 52.4%) registered in the Humana Inc claims dataset who underwent anterior cervical fusion (ACF) or posterior cervical fusion (PCF) between 2007 and 2015. OUTCOME MEASURES: Prolonged opioid usage was defined as narcotic prescription filling at 1 year following cervical arthrodesis. METHODS: Based on preoperative opioid use, patients were identified as an OU (history of narcotic prescription filled within 3 months before surgery) or a NOU (no preoperative prescription). Rates of opioid use were evaluated preoperatively for OU and trended for 1 year postoperatively for both OU and NOU. Multivariable regression techniques investigated factors associated with the use of narcotics at 1 year following ACF and PCF. Based on the model findings, a web-based interactive app was developed to estimate 1-year postoperative risk of using narcotics following cervical arthrodesis (http://neuro-risk.com/opiod-use/ or https://www.neurosurgerycost.com/opioid/opioid_use). RESULTS: Overall, 87.4% of the patients (n=15,204) underwent ACF, whereas 12.6% (n=2187) underwent PCF. At 1 month following surgery, 47.7% of NOUs and 82% of OUs had a filled opioid prescription. Rates of prescription opioids declined significantly to 7.8% in NOUs versus 50.5% in OUs at 3 months, but plateaued at the 6- to 12-month postoperative period (NOU: 5.7%-6.7%, OU: 44.9%-46.9%). At 1 year, significantly higher narcotic prescription filling rates were observed in OUs compared with NOUs (45.3% vs. 6.3%, p<.001). Preoperative opioid use was a significant driver of 1-year narcotic use following ACF (odds ratio [OR]: 7.02, p<.001) and PCF (OR: 6.98, p<.001), along with younger age (≤50 years), history of drug dependence, and lower back pain. CONCLUSIONS: Over 50% of the patients used opioids before cervical arthrodesis. Postoperative opioid use fell dramatically during the first 3 months in NOU, but nearly half of the preoperative OUs will remain on narcotics at 1 year postoperatively. Our findings serve as a baseline in identifying patients at risk of chronic use and encourage discontinuation of opioids before cervical spine surgery.

Targeting mitochondrial responses to intra-articular fracture to prevent posttraumatic osteoarthritis.

We tested whether inhibiting mechanically responsive articular chondrocyte mitochondria after severe traumatic injury and preventing oxidative damage represent a viable paradigm for posttraumatic osteoarthritis (PTOA) prevention. We used a porcine hock intra-articular fracture (IAF) model well suited to human-like surgical techniques and with excellent anatomic similarities to human ankles. After IAF, amobarbital or N-acetylcysteine (NAC) was injected to inhibit chondrocyte electron transport or downstream oxidative stress, respectively. Effects were confirmed via spectrophotometric enzyme assays or glutathione/glutathione disulfide assays and immunohistochemical measures of oxidative stress. Amobarbital or NAC delivered after IAF provided substantial protection against PTOA at 6 months, including maintenance of proteoglycan content, decreased histological disease scores, and normalized chondrocyte metabolic function. These data support the therapeutic potential of targeting chondrocyte metabolism after injury and suggest a strong role for mitochondria in mediating PTOA.

Personal exposure to fine particulate air pollution while commuting: An examination of six transport modes on an urban arterial roadway.

Traffic-related air pollution in urban areas contributes significantly to commuters' daily PM2.5 exposures, but varies widely depending on mode of commuting. To date, studies show conflicting results for PM2.5 exposures based on mode of commuting, and few studies compare multiple modes of transportation simultaneously along a common route, making inter-modal comparisons difficult. In this study, we examined breathing zone PM2.5 exposures for six different modes of commuting (bicycle, walking, driving with windows open and closed, bus, and light-rail train) simultaneously on a single 2.7 km (1.68 mile) arterial urban route in Salt Lake City, Utah (USA) during peak "rush hour" times. Using previously published minute ventilation rates, we estimated the inhaled dose and exposure rate for each mode of commuting. Mean PM2.5 concentrations ranged from 5.20 µg/m3 for driving with windows closed to 15.21 µg/m3 for driving with windows open. The estimated inhaled doses over the 2.7 km route were 6.83 µg for walking, 2.78 µg for cycling, 1.28 µg for light-rail train, 1.24 µg for driving with windows open, 1.23 µg for bus, and 0.32 µg for driving with windows closed. Similarly, the exposure rates were highest for cycling (18.0 µg/hr) and walking (16.8 µg/hr), and lowest for driving with windows closed (3.7 µg/hr). Our findings support previous studies showing that active commuters receive a greater PM2.5 dose and have higher rates of exposure than commuters using automobiles or public transportation. Our findings also support previous studies showing that driving with windows closed is protective against traffic-related PM2.5 exposure.