Cervical Spine Stenosis Causing Diaphragmatic Paralysis: A Case Study and Narrative Review of Clinical Presentations and Outcomes.

STUDY DESIGN: Case report and narrative review. OBJECTIVE: To explore the therapeutic role of surgical and nonsurgical treatment of diaphragmatic paralysis secondary to spinal cord and nerve root compression. SUMMARY OF BACKGROUND DATA: Phrenic nerve dysfunction due to central or neuroforaminal stenosis is a rare yet unappreciated etiology of diaphragmatic paralysis and chronic dyspnea. Surgical spine decompression, diaphragmatic pacing, and intensive physiotherapy are potential treatment options with varying degrees of evidence. METHODS: The case of a 70-year-old male with progressive dyspnea, reduced hemi-diaphragmatic excursion, and C3-C7 stenosis, who underwent a microscopic foraminotomy is discussed. Literature review (MEDLINE, PubMed, Google Scholar) identified 19 similar reports and discussed alternative treatments and outcomes. RESULTS AND CONCLUSIONS: Phrenic nerve root decompression and improvement in neuromonitoring signals were observed intraoperatively. The patient's postoperative course was uncomplicated, and after 15 months, he experienced significant symptomatic improvement and minor improvement in hemi-diaphragmatic paralysis and pulmonary function tests. All case reports of patients treated with spinal decompression showed symptomatic and/or functional improvement, while one of the 2 patients treated with physiotherapy showed improvement. More studies are needed to further describe the course and outcomes of these interventions, but early identification and spinal decompression can be an effective treatment. OCEBM LEVEL OF EVIDENCE: Level-4.

Evaluating Adult Idiopathic Scoliosis as an Independent Risk Factor for Critical Illness in SARS-CoV-2 Infection.

BACKGROUND: Thoracic spinal deformities may reduce chest wall compliance, leading to respiratory complications. The first SARS-CoV-2 (L-variant) strain caused critical respiratory illness, especially in vulnerable patients. This study investigates the association between scoliosis and SARS-CoV-2 (COVID-19) disease course severity. METHODS: Clinical data of 129 patients treated between March 2020 to June 2021 who received a positive COVID-19 polymerase chain reaction result from Mount Sinai and had a scoliosis ICD-10 code (M41.0-M41.9) was retrospectively analyzed. Degree of coronal plane scoliosis on imaging was confirmed by 2 independent measurers and grouped into no scoliosis (Cobb angle <10°), mild (10°-24°), moderate (25°-39°), and severe (>40°) cohorts. Baseline characteristics were compared, and a multivariable logistic regression controlling for clinically significant comorbidities examined the significance of scoliosis as an independent risk factor for hospitalization, intensive care unit (ICU) admission, acute respiratory distress syndrome (ARDS), mechanical ventilation, and mortality. RESULTS: The no (n = 42), mild (n = 14), moderate (n = 44), and severe scoliosis (n = 29) cohorts differed significantly only in age (P = 0.026). The percentage of patients hospitalized (P = 0.59), admitted to the ICU (P = 0.33), developing ARDS (P = 0.77), requiring mechanical ventilation (P = 1.0), or who expired (P = 0.77) did not significantly differ between cohorts. The scoliosis cohorts did not have a significantly higher likelihood of hospital admission (mild P = 0.19, moderate P = 0.67, severe P = 0.98), ICU admission (P = 0.97, P = 0.94, P = 0.22), ARDS (P = 0.87, P = 0.74, P = 0.94), mechanical ventilation (P = 0.73, P = 0.69, P = 0.70), or mortality (P = 0.74, P = 0.87, P = 0.66) than the no scoliosis cohort. CONCLUSIONS: Scoliosis was not an independent risk factor for critical COVID-19 illness. No trends indicated any consistent effect of degree of scoliosis on increased adverse outcome likelihood.

Effects of repetitive head trauma on symptomatology of subsequent sport-related concussion.

OBJECTIVE: Adolescent participation in athletics continues to grow, leading to an increasing incidence of sports-related concussion (SRC). The current literature suggests that a greater number of prior concussions positively correlates with a greater number of total symptoms, but the specific concussion-related symptoms are not as well defined. The current study investigated the effects of prior recurrent head injury on the symptom profiles of student-athletes after another suspected concussion. METHODS: A multicenter database consisting of 25,815 Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) results was filtered for student-athletes aged 12-22 years old who competed in 21 different sports. Patients were separated into 2 cohorts: athletes reporting a single prior concussion (SRC1) and athletes reporting 2 or more prior concussions (SRC2+). Comparisons were assessed for differences in 22 symptoms and 4 symptom clusters at baseline, first postinjury test (PI1), and second postinjury test (PI2) by using univariate and multivariate analyses. RESULTS: No differences were seen between SRC1 (n = 2253) and SRC2+ (n = 976) at baseline. At PI1, the SRC2+ group (n = 286) had lower severity of headaches (p = 0.04) but increased nervousness (p = 0.042), irritability (p = 0.028), sadness (p = 0.028), visual problems (p = 0.04), and neuropsychiatric symptoms (p = 0.009) compared with SRC1 (n = 529). Multivariate analysis revealed decreased headache severity with increased prior concussion (ß = -0.27,95% CI -0.45 to -0.09, p = 0.003). Multivariate analysis at PI2 demonstrated the SRC2+ cohort (n = 130) had increased cognitive (ß = 1.22, 95% CI 0.27-2.18, p = 0.012), sleep (ß = 0.63, 95% CI 0.17-1.08, p = 0.007), and neuropsychiatric (ß = 0.67,95% CI 0.14-1.2,0.014) symptoms compared with SRC1 (n = 292). CONCLUSIONS: At longitudinal follow-up, patients with a history of recurrent concussions reported greater symptom burden in cognitive, sleep, and neuropsychiatric symptom clusters but not migraine symptoms. This is an important distinction because migraine symptoms are often more easily distinguishable to patients, parents, and physicians. Careful assessment of specific symptoms should be considered in patients with a history of recurrent head injury prior to return to play.

Testing and Optimizing Guided Thinking Tasks to Promote Physical Activity: Protocol for a Randomized Factorial Trial.

BACKGROUND: Insufficient physical activity is associated with various health risks; however, most current physical activity interventions have critical barriers to scalability. Delivering interventions via technology and identifying active and inert components in early-phase development are ways to build more efficient and scalable interventions. We developed a novel intervention to promote physical activity that targets 3 brief guided thinking tasks, separately and in combination, using brief audio recordings: (1) episodic future thinking (EFT), (2) positive affective imagery (PAI), and (3) planning. OBJECTIVE: The aim of this GeT (Guided Thinking) Active study is to optimize a scalable guided thinking intervention to promote physical activity using principles of the Multiphase Optimization Strategy (MOST). Mechanism-focused analyses will inform which components are optimal candidates for inclusion in an intervention package and which need refinement. METHODS: We will enroll 192 participants randomized to receive intervention components delivered via an audio recording that they will listen to prior to weekly in-lab physical activity sessions. Participants in the high dose conditions will also be instructed to listen to the audio recording 4 additional days each week. We will evaluate effects of the components on physical activity over 6 weeks in a 2 (EFT vs recent thinking) × 2 (PAI vs neutral imagery) × 2 (planning vs no planning) × 2 (dose: 5×/week vs 1×/week) full factorial randomized trial. RESULTS: The National Cancer Institute funded this study (R21CA260360) on May 13, 2021. Participant recruitment began in February 2022. Data analysis will begin after the completion of data collection. CONCLUSIONS: The GeT Active study will result in a scalable, audio-recorded intervention that will accelerate progress toward the full development of guided thinking interventions to promote physical activity. TRIAL REGISTRATION: ClinicalTrials.gov NCT05235360; https://clinicaltrials.gov/ct2/show/NCT05235360. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/40908.

Is there a morphometric cause of Chiari malformation type I? Analysis of existing literature.

Although many etiologies have been proposed for Chiari malformation type I (CM-I), there currently is no singular known cause of CM-I pathogenesis. Advances in imaging have greatly progressed the study of CM-I. This study reviews the literature to determine if an anatomical cause for CM-I could be proposed from morphometric studies in adult CM-I patients. After conducting a literature search using relevant search terms, two authors screened abstracts for relevance. Full-length articles of primary morphometric studies published in peer-reviewed journals were included. Detailed information regarding methodology and symptomatology, craniocervical instability, syringomyelia, operative effects, and genetics were extracted. Forty-six studies met inclusion criteria, averaging 93.2 CM-I patients and 41.4 healthy controls in size. To obtain measurements, 40 studies utilized MRI and 10 utilized CT imaging, whereas 41 analyzed parameters within the posterior fossa and 20 analyzed parameters of the craniovertebral junction. The most commonly measured parameters included clivus length (n = 30), tonsillar position or descent (n = 28), McRae line length (n = 26), and supraocciput length (n = 26). While certain structural anomalies including reduced clivus length have been implicated in CM-I, there is a lack of consensus on how several other morphometric parameters may or may not contribute to its development. Heterogeneity in presentation with respect to the extent of tonsillar descent suggests alternate methods utilizing morphometric measurements that may help to identify CM-I patients and may benefit future research to better understand underlying pathophysiology and sequelae such as syringomyelia.

Surgical Start Time Is Not Predictive of Microdiscectomy Outcomes.

STUDY DESIGN: Retrospective analysis of clinical data from a single institution. OBJECTIVE: The objective of this study was to assess the time of surgery as a possible predictor for outcomes, length of stay, and cost following microdiscectomy. SUMMARY OF BACKGROUND DATA: The volume of microdiscectomy procedures has increased year over year, heightening interest in surgical outcomes. Previous investigations have demonstrated an association between time of procedures and clinical outcomes in various surgeries, however, no study has evaluated its influence on microdiscectomy. METHODS: Demographic and outcome variables were collected from all patients that underwent a nonemergent microdiscectomy between 2008 and 2016. Patients were divided into 2 cohorts: those receiving surgery before 2 pm were assigned to the early group and those with procedures beginning after 2 pm were assigned to the late group. Outcomes and patient-level characteristics were compared using bivariate, multivariable logistic, and linear regression models. Adjusted length of stay and cost were coprimary outcomes. Secondary outcomes included operative complications, nonhome discharge, postoperative emergency department visits, or readmission rates. RESULTS: Of the 1261 consecutive patients who met the inclusion criteria, 792 were assigned to the late group and 469 were assigned to the early group. There were no significant differences in demographics or baseline characteristics between the 2 cohorts. In the unadjusted analysis, mean length of stay was 1.80 (SD=1.82) days for the early group and 2.00 (SD=1.70) days for the late group (P=0.054). Mean direct cost for the early cohort was $5088 (SD=$4212) and $4986 (SD=$2988) for the late cohort (P=0.65). There was no difference in adjusted length of stay or direct cost. No statistically significant differences were found in operative complications, nonhome discharge, postoperative emergency department visits, or readmission rates between the 2 cohorts. CONCLUSION: The study findings suggest that early compared with late surgery is not significantly predictive of surgical outcomes following microdiscectomy.

Assessing the Impact of Neurogenic Claudication on Outcomes Following Decompression With Lumbar Interbody Fusions in Patients With Lumbar Spinal Stenosis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To conduct the first comprehensive national-level study examining specific risks, outcomes, and costs surrounding surgical treatment of lumar spinal stenosis (LSS) in patients with and without neurogenic claudication (NC). METHODS: Data for patients with or without NC who underwent decompression with a lumbar interbody fusion approached anteriorly (ALIF), posteriorly (PLIF), or laterally (LLIF) for LSS was collected from the 2013-2014 National Inpatient Sample using International Classification of Disease codes. RESULTS: A total of 121 025 LSS cases without NC and 20 095 cases with NC were included in this study. The most significant complications associated with NC status by organ system included renal (P = .0030) and hematological complications (P = .0003). Multivariate regression controlling for key demographic and comorbidity variables showed that patients with NC did not have significantly higher odds of complication, non-home discharge, or extended hospitalization compared to patients without NC regardless of fusion type. Interestingly, NC patients had comparatively lower total charges for their hospitalization following PLIFs (P = .0001) and LLIFs (P < .0001), but not ALIFs (P = .6121). CONCLUSION: NC does not appear to significantly increase odds of adverse outcomes following fusion in LSS. Given the large prevalence of LSS and coincidental NC, these findings may carry important implications in managing this challenging patient population and justifies future prospective investigation of this topic.

Surgery for spinal deformity: non-elective admission status is associated with higher cost of care and longer length of stay.

INTRODUCTION: Surgery is commonly indicated for adult spinal deformity. Annual rates and costs of spinal deformity surgery have both increased over the past two decades. However, the impact of non-elective status on total cost of hospitalization and patient outcomes has not been quantified. OBJECTIVE: To evaluate the impact of admission status on patient outcomes and healthcare costs in spinal deformity surgery. METHODS: All patients who underwent spinal deformity surgery at a single institution between 2008 and 2016 were grouped by admission status: elective, emergency (ED), or transferred. Demographics were compared by univariate analysis. Cost of care and length of stay (LOS) were compared between admission statuses using multivariable linear regression with elective admissions as reference. Multivariate logistic regression was utilized to assess in-hospital complications, discharge destination, and readmission rates. RESULTS: There were 427 spinal deformity surgeries included in this study. Compared to elective patients, ED patients had higher Elixhauser Comorbidity Index scores (p < 0.0001), longer LOS (+ 10.9 days, 97.5% CI 6.1-15.6 days, p < 0.0001), and higher costs (+ $20,076, 97.5% CI $9,073-$31,080, p = 0.0008). Transferred patients had significantly higher Elixhauser scores (p = 0.0002), longer LOS (+ 8.8 days, 97.5% CI 3.0-14.7 days, p < 0.0001), and higher rates of non-home discharge (OR = 15.8, 97.5% CI 2.3-110.0, p = 0.001). CONCLUSION: Patients admitted from the ED undergoing spinal deformity surgery had significantly higher cost of care and longer LOS compared to elective patients. Transferred patients had significantly longer LOS and a higher rate of non-home discharge compared to elective patients.

A Comparison of Outcomes for Spinal Trauma Patients at Level I and Level II Centers.

STUDY DESIGN: Retrospective analysis of a national database. OBJECTIVE: To characterize the spine trauma population, describe trauma center (TC) resources, and compare rates of outcomes between the American College of Surgeons (ACS) level I and level II centers. SUMMARY OF BACKGROUND DATA: Each year, thousands of patients are treated for spinal trauma in the United States. Although prior analyses have explored postsurgical outcomes for patients with trauma, no study has evaluated these metrics for spinal trauma at level I and level II TCs. MATERIALS AND METHODS: The ACS Trauma Quality Improvement Program was queried for all spinal trauma cases between 2013 and 2015, excluding polytrauma cases, patients discharged within 24 hours, data from TCs without a designated level, and patients transferred for treatment. RESULTS: Although there were similar rates of severe spine traumas (Abbreviated Injury Scale≥3) at ACS level I and level II centers (P=0.7), a greater proportion of level I patients required mechanical ventilation upon emergency department arrival (P=0.0002). Patients at level I centers suffered from higher rates of infectious complications, including severe sepsis (0.58% vs. 0.31%, P=0.02) and urinary tract infections (3.26% vs. 2.34%, P=0.0009). Intensive care unit time (1.90 vs. 1.65 days, P=0.005) and overall length of stay (8.37 days vs. 7.44 days, P<0.0001) was higher at level I TCs. Multivariate regression revealed higher adjusted overall complication rates at level II centers (odds ratio, 1.15, 95% confidence interval, 1.06-1.24; P<0.001), but no difference in mortality (odds ratio, 1.18; 95% confidence interval, 0.92-1.52; P>0.10). CONCLUSIONS: ACS level I TCs possess larger surgical staff and are more likely to be academic centers. Patients treated at level I centers experience fewer overall complications but have a greater incidence of infectious complications. Mortality rates are not statistically different.

Afternoon Surgical Start Time Is Associated with Higher Cost and Longer Length of Stay in Posterior Lumbar Fusion.

BACKGROUND: Existing research about surgical start time is equivocal about associations between outcomes and late start times, and there is only one published report investigating start time in spine surgery. Therefore, the objective of this study was to assess associations between surgical start time, length of stay (LOS), and cost in lumbar spine surgery. METHODS: Patients at a single institution undergoing posterior lumbar fusion (PLF) were grouped based on whether they received their surgery before or after 2 pm, with those receiving their surgery between 12 am and 6 am and receiving surgery for tumors, trauma, or infections being excluded. These 2 groups were then compared on the basis of demographics and outcomes with cost and LOS as the coprimary outcomes. RESULTS: A total of 2977 patients underwent PLF during the study period. There were minimal differences in preoperative characteristics of the cohorts. The patients who underwent PLF starting after 2 pm had longer LOS (0.45 days; 95% confidence interval [CI], 0.18-0.72; P = 0.001) and higher costs ($1343; 95% CI, $339-$2348; P = 0.009) than cases starting before 2 pm The late surgical start cohort also had higher rates of nonhome discharge (29.73% vs. 23.17%, P = 0.0004), and 30-day (4.36% vs. 2.5%, P = 0.01) and 90-day emergency department visits (5.72% vs. 2.94%, P = 0.0005). CONCLUSIONS: Late surgical start time is associated with longer LOS and higher cost in patients undergoing PLF.

Utility of the Hospital Frailty Risk Score for Predicting Adverse Outcomes in Degenerative Spine Surgery Cohorts.

BACKGROUND: As spine surgery becomes increasingly common in the elderly, frailty has been used to risk stratify these patients. The Hospital Frailty Risk Score (HFRS) is a novel method of assessing frailty using International Classification of Diseases, Tenth Revision (ICD-10) codes. However, HFRS utility has not been evaluated in spinal surgery. OBJECTIVE: To assess the accuracy of HFRS in predicting adverse outcomes of surgical spine patients. METHODS: Patients undergoing elective spine surgery at a single institution from 2008 to 2016 were reviewed, and those undergoing surgery for tumors, traumas, and infections were excluded. The HFRS was calculated for each patient, and rates of adverse events were calculated for low, medium, and high frailty cohorts. Predictive ability of the HFRS in a model containing other relevant variables for various outcomes was also calculated. RESULTS: Intensive care unit (ICU) stays were more prevalent in high HFRS patients (66%) than medium (31%) or low (7%) HFRS patients. Similar results were found for nonhome discharges and 30-d readmission rates. Logistic regressions showed HFRS improved the accuracy of predicting ICU stays (area under the curve [AUC] = 0.87), nonhome discharges (AUC = 0.84), and total complications (AUC = 0.84). HFRS was less effective at improving predictions of 30-d readmission rates (AUC = 0.65) and emergency department visits (AUC = 0.60). CONCLUSION: HFRS is a better predictor of length of stay (LOS), ICU stays, and nonhome discharges than readmission and may improve on modified frailty index in predicting LOS. Since ICU stays and nonhome discharges are the main drivers of cost variability in spine surgery, HFRS may be a valuable tool for cost prediction in this specialty.

Later Surgical Start Time Is Associated With Longer Length of Stay and Higher Cost in Cervical Spine Surgery.

STUDY DESIGN: Retrospective study of a surgical cohort from a single, large academic institution. OBJECTIVE: The aim of this study was to investigate associations between surgical start time, length of stay, cost, perioperative outcomes, and readmission. SUMMARY OF BACKGROUND DATA: One retrospective study with a smaller cohort investigated associations between surgical start time and outcomes in spine surgery and found that early start times were correlated with shorter length of stay. No examinations of perioperative outcomes or cost have been performed. METHODS: All patients undergoing anterior cervical discectomy and fusion (ACDF) and posterior cervical decompression and fusion (PCDF) were queried from a single institution from January 1, 2008 to November 30, 2016. Patients undergoing surgery that started between 12:00 AM and 6:00 AM were excluded due to their likely emergent nature. Cases starting before and after 2:00 PM were compared on the basis of length of stay and cost as the primary outcomes using multivariable logistic regression. RESULT: The patients undergoing ACDF and PCDF were both similar on the basis of comorbidity burden, preoperative diagnosis, and number of segments fused. The patients undergoing ACDF starting after 2 PM had longer LOS values (adjusted difference of 0.65 days; 95% confidence interval [CI]: 0.28-1.03; P = 0.0006) and higher costs of hospitalization (adjusted difference of $1177; 95% CI: $549-$1806; P = 0.0002). Patients undergoing PCDF starting after 2 PM also had longer LOS values (adjusted difference of 1.19 days; 95% CI: 0.46-1.91; P = 0.001) and higher costs of hospitalization (adjusted difference of $2305; 95% CI: $826-$3785; P = 0.002). CONCLUSION: Later surgical start time is associated with longer LOS and higher cost. These findings should be further confirmed in the spine surgical literature to investigate surgical start time as a potential cost-saving measure. LEVEL OF EVIDENCE: 3.

Adult spinal deformity surgery: the effect of surgical start time on patient outcomes and cost of care.

PURPOSE: There are reports investigating the effect of surgical start time (SST) on outcomes, length of stay (LOS) and cost in various surgical disciplines. However, this has not been studied in spine deformity surgery to date. This study compares outcomes for patients undergoing spinal deformity surgery based on SST. METHODS: Patients at a single academic institution from 2008 to 2016 undergoing elective spinal deformity surgery (defined as fusing ≥ 7 segments) were divided by SST before or after 2 PM. Co-primary outcomes were LOS and direct costs. Secondary outcomes included delayed extubation, ICU stay, complications, reoperation, non-home discharge, and readmission rates. RESULTS: There were 373 surgeries starting before 2 PM and 79 after 2 PM. The cohorts had similar demographics including age, sex, comorbidity burden, and levels fused. The late SST cohort had shorter operation durations (p = 0.0007). Multivariable linear regression showed no differences in LOS (estimate 0.4 days, CI - 1.2 to 2.0, p = 0.64) or direct cost (estimate $3652, 95% CI - $1449 to $8755, p = 0.16). Multivariable logistic regression revealed the late SST cohort was more likely to have delayed extubation (OR 2.6, 95% CI 1.4-4.9, p = 0.004) and non-home discharge (OR 2.2, 95% CI 1.1-4.2, p = 0.03). All other secondary outcomes were non-significant. CONCLUSION: Patients undergoing spinal deformity surgery before and after 2 PM have similar LOS and cost of care. However, the late SST cohort had increased likelihood of delayed extubation and non-home discharges, which increase cost in bundled payment models. These findings can be utilized in OR scheduling to optimize outcomes and minimize cost.

Increased Risk of Transient Cerebral Ischemia After Subarachnoid Hemorrhage in Patients with Premorbid Opioid Use Disorders: A Nationwide Analysis of Outcomes.

BACKGROUND: Subarachnoid hemorrhage (SAH) is the most morbid sequela of intracranial aneurysms. Although mortality from SAH has been declining, opioid use in the United States has surged, and neurosurgeons are increasingly tasked with operating on patients with opioid use disorders (OUDs). There is a deficit in the literature regarding how OUDs affect SAH outcomes, particularly transient cerebral ischemic (TCI) events. The objective of this study was to investigate the influence of clinically diagnosed OUDs on the outcomes after acute SAH, with a specific focus on the rate of symptomatic TCI. METHODS: Patients with and without a diagnosed OUD who underwent either microsurgical clipping or endovascular coiling for SAH were queried from the 2012-2014 National Inpatient Sample using International Classification of Disease codes. The primary outcome was the rate of TCI after SAH treatment. RESULTS: A total of 25,330 patients were included, 310 of whom (1.22%) also carried a diagnosis of OUD. Univariate and multivariate regression showed that patients with OUD faced significantly increased odds of TCI (P = 0.044) compared with patients without OUD. OUD status was not associated with increased odds of other adverse outcomes, including overall complication, in-hospital mortality, poor outcome by a validated National Inpatient Sample SAH Outcome Measure, nonhome discharge, or extended hospitalization. CONCLUSIONS: Patients with OUD face significantly higher odds of symptomatic TCI events producing clinical deficits during hospitalization for acute SAH. These findings suggest usefulness in screening patients for OUD to identify individuals who may benefit from a higher level of clinical scrutiny for post-SAH TCI.

Correction to: Adult spinal deformity surgery: the effect of surgical start time on patient outcomes and cost of care.

The original version of this article unfortunately contained a mistake. The first name of the author "Samuel Z. Maron" was incorrectly provided as "Sam" instead of "Samuel".

Adjacent Segment Reoperation and Other Perioperative Outcomes in Patients Who Underwent Anterior Lumbar Interbody Fusions at One and Two Levels.

OBJECTIVE: This is the first large retrospective analysis of patients undergoing anterior lumbar interbody fusion (ALIF) with concern for clinical determinants leading to reoperation for adjacent segment disease (ASD). The objective of this study is to examine the specific perioperative and clinical determinants that affect need for adjacent segment reoperation in patients who underwent 1-level and 2-level ALIF procedures for degenerative disc disorders. METHODS: All cases at our institution between 2008 and 2016 involving an ALIF performed for degenerative disc disorders at 1 or 2 levels were examined. A total of 404 ALIF cases, of which 268 were single-level (66.33%) and 136 were 2-level procedures (33.67%), were included. Adjacent segment reoperation was the primary outcome. Secondary outcomes included increased blood loss, extended surgery duration, greater nonhome discharge, extended hospitalization, and higher total direct costs. Univariate and multivariate logistic regression assessed how number of levels fused related to perioperative outcomes. RESULTS: The patient cohorts shared similar demographic characteristics and showed expected differences in certain intraoperative outcomes. After controlling for preoperative and intraoperative variables, multivariate regression showed that patients who underwent 2-level ALIFs experienced increased odds of adjacent segment reoperation (P = 0.0424) but no other adverse clinical outcomes. CONCLUSIONS: Our findings support a biomechanical hypothesis of ASD onset after fusion, suggesting that the risk of ASD after ALIF lies primarily in the number of levels fused rather than any demographic or intraoperative variables.

Elixhauser Comorbidity Measure is Superior to Charlson Comorbidity Index In-Predicting Hospital Complications Following Elective Posterior Cervical Decompression and Fusion.

OBJECTIVE: The predictive ability of Elixhauser Comorbidity Index (ECI) and Charlson Comorbidity Index (CCI) have been compared in orthopedic and gastrointestinal surgery; however, their predictive ability for complications secondary to spine surgery and posterior cervical decompression and fusion (PCDF) specifically is understudied. This study examines the predictive ability of the ECI and CCI for complications and morbidity following PCDF. METHODS: ECI and CCI were retrospectively computed for all PCDF cases in the National Inpatient Sample database from 2013 to 2014 and complications or morbidity were identified. C-statistics were used to analyze ECI and CCI predictive ability in a range of complications and compared with a base comorbidity model that included age, sex, race, and primary payer. RESULTS: PCDF was performed in 46,700 hospitalizations between 2013 and 2014. The complications for which ECI was found to be a significantly better predictor included airway complications (69.16% superior to CCI), hemorrhagic anemia (79.04% superior), cardiac arrest (72.39% superior), pulmonary embolism (83.01% superior), sepsis (62.44% superior), septic shock (78.90% superior), urinary tract infection (63.53% superior), death (74.28% superior), any minor complication (75% superior), any major complication (133% superior), and any complication at all (63.72% superior). The complications for which neither the ECI Index nor the CCI proved superior were acute kidney injury, myocardial infarction, cerebrovascular accident, deep vein thrombosis, pneumonia, wound dehiscence, and superficial surgical-site infection following PCDF. CONCLUSIONS: ECI showed superior predictive ability to the CCI in predicting 8 of the 18 complications that were analyzed and inferior in none.

von Willebrand factor and factor VIII are independently required to form stable occlusive thrombi in injured veins.

von Willebrand factor (VWF) protects factor VIII (FVIII) from proteolysis and mediates the initial contact of platelets with the injured vessel wall, thus playing an important role in hemostasis and thrombosis. VWF is crucial for the formation of occlusive thrombi at arterial shear rates. However, with only a few conflicting studies published, the role of VWF in venous thrombosis is still unclear. Using gene-targeted mice, we show that in ferric chloride-injured veins platelet adhesion to subendothelium is decreased and thrombus growth is impaired in VWF(-/-) mice when compared with wild type (WT). We also observed increased embolization in the VWF(-/-) mice, which was due to lower FVIII levels in these mice as recombinant factor VIII (r-FVIII) restored thrombus stability. Despite normalization of blood clotting time and thrombus stability after r-FVIII infusion, the VWF(-/-) venules did not occlude. Transgenic platelets lacking the VWF receptor GPIbalpha extracellular domain showed decreased adhesion to injured veins. But, after a delay, all the injured venules occluded in these transgenic mice. Thus, VWF likely uses other adhesion receptors besides GPIbalpha in thrombus growth under venous shear conditions. Our studies document crucial roles for VWF and FVIII in experimental thrombosis under venous flow conditions in vivo.

Systemic antithrombotic effects of ADAMTS13.

The metalloprotease ADAMTS13 (a disintegrin-like and metalloprotease with thrombospondin type I repeats 13) cleaves highly adhesive large von Willebrand factor (VWF) multimers after their release from the endothelium. ADAMTS13 deficiency is linked to a life-threatening disorder, thrombotic thrombocytopenic purpura (TTP), characterized by platelet-rich thrombi in the microvasculature. Here, we show spontaneous thrombus formation in activated microvenules of Adamts13-/- mice by intravital microscopy. Strikingly, we found that ADAMTS13 down-regulates both platelet adhesion to exposed subendothelium and thrombus formation in injured arterioles. An inhibitory antibody to ADAMTS13 infused in wild-type mice prolonged adhesion of platelets to endothelium and induced thrombi formation with embolization in the activated microvenules. Absence of ADAMTS13 did not promote thrombi formation in alphaIIbbeta3 integrin-inhibited blood. Recombinant ADAMTS13 reduced platelet adhesion and aggregation in histamine-activated venules and promoted thrombus dissolution in injured arterioles. Our findings reveal that ADAMTS13 has a powerful natural antithrombotic activity and recombinant ADAMTS13 could be used as an antithrombotic agent.

Shigatoxin triggers thrombotic thrombocytopenic purpura in genetically susceptible ADAMTS13-deficient mice.

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening illness caused by deficiency of the vWF-cleaving protease ADAMTS13. Here we show that ADAMTS13-deficient mice are viable and exhibit normal survival, although vWF-mediated platelet-endothelial interactions are significantly prolonged. Introduction of the genetic background CASA/Rk (a mouse strain with elevated plasma vWF) resulted in the appearance of spontaneous thrombocytopenia in a subset of ADAMTS13-deficient mice and significantly decreased survival. Challenge of these mice with shigatoxin (derived from bacterial pathogens associated with the related human disease hemolytic uremic syndrome) resulted in a striking syndrome closely resembling human TTP. Surprisingly, no correlation was observed between plasma vWF level and severity of TTP, implying the existence of TTP-modifying genes distinct from vWF. These data suggest that microbe-derived toxins (or possibly other sources of endothelial injury), together with additional genetic susceptibility factors, are required to trigger TTP in the setting of ADAMTS13 deficiency.