Chronic Anticoagulation in Patients Who Have Atrial Fibrillation Undergoing Outpatient Total Knee Arthroplasty: A Retrospective Matched Cohort Study.

BACKGROUND: Patients who have atrial fibrillation frequently require long-term anticoagulation with warfarin or a direct-acting oral anticoagulant (DOAC), such as apixaban or rivaroxaban, to avoid vascular complications. However, the impact of anticoagulant use on postoperative complications following total knee arthroplasty (TKA) in an outpatient setting has not been thoroughly elucidated. The purpose of this study was to examine the impact of anticoagulant use on early postoperative complications among atrial fibrillation patients undergoing outpatient TKA. METHODS: An insurance claims database was queried to identify all patients who underwent outpatient TKA between January 2010 and April 2022. There were two cohorts of patients, with associated 1:1 matched controls, who had atrial fibrillation and filled a prescription of either warfarin (N = 4,396) or DOAC (N = 5,383) for at least 30 days. The mean age was 70 years (range, 51 to 84 years) and 47.9% were women in the warfarin cohort, while the mean age was 70 years and 49.2% were women in the DOAC cohort. Postoperative 30-day medical and 90-day surgical complications were subsequently compared. RESULTS: Patients on warfarin had a higher incidence of pulmonary embolism (1.1 versus 0.2%, P < 0.001) and a lower incidence of TKA revision (0.1 versus 0.4%, P = 0.003) than matched controls. Similarly, patients on DOACs exhibited a higher incidence of pneumonia (1.4 versus 0.6%, P < 0.001) and myocardial infarction (3.2 versus 1.5%, P < 0.001) and a lower incidence of wound dehiscence (0.1 versus 0.5%, P < 0.001), joint infection (0.4 versus 0.9%, P = 0.002), and TKA revision (0.1 versus 0.4%, P = 0.002) than matched controls. CONCLUSIONS: Atrial fibrillation patients on long-term anticoagulants undergoing outpatient TKA experience higher rates of medical complications and lower rates of surgical complications than matched controls. Thus, patients on long-term anticoagulants may be considered for outpatient TKA, but should be counseled appropriately on associated medical risks.

Assessing Abnormal Proximal Junctional Angles in Adult Spinal Deformity: A Normative Data Approach to Define Proximal Junctional Kyphosis.

STUDY DESIGN: Multicentric retrospective study of prospectively collected data. OBJECTIVE: Based on normative data from a cohort of asymptomatic volunteers, this study sought to determine the rate of abnormal values of proximal junctional angles (PJA) in adult spinal deformity (ASD) surgery patients, and compare it with PJK rate. SUMMARY OF BACKGROUND DATA: Proximal junctional kyphosis (PJK) definition does not take the vertebral level into account. METHODS: This study included 721 healthy volunteers and 824 ASD surgery patients with 2-year postoperative follow-up. Normative values for each disc and vertebral body between T1 and T12 were analyzed, then normative values for PJA at each thoracic level were defined in the volunteer cohort as the mean±2 standard deviations. PJA abnormal values at the upper instrumented vertebra (UIV) were compared with Glattes' and Lovecchio's definitions for PJK in the ASD population at two years. RESULTS: Mean age was 37.7±16.3 in the volunteer cohort, with 50.5% of females. Mean thoracic kyphosis (TK) was -50.9±10.8°. Corridors of normality included PJA greater than 20° between T3 and T12. Mean age was 60.5±14.0 years in the ASD cohort, with 77.2% of females. Mean baseline TK was -37.4±19.9°, with a significant increase after surgery (-15.6±15.3°, P<0.001). There was 46.2% of PJK according to Glattes' versus 8.7% according to Lovecchio's and 22.9% of kyphotic PJA compared to normative values (P<0.001). CONCLUSION: This study provides normative values for segmental and regional alignment of thoracic spine, used to describe abnormal values of PJA for each level. Using level-adjusted PJA values allows a more precise assessment of abnormal proximal angles and question the definition for PJK. LEVEL OF EVIDENCE: II.

Do Obese Patients Have Worse Outcomes in Adult Spinal Deformity Surgeries? A Meta-Analysis.

STUDY DESIGN: Meta-Analysis. OBJECTIVE: This meta-analysis evaluates the difference in surgical outcomes between obese and non-obese patients undergoing adult spinal deformity (ASD) corrective surgery. BACKGROUND: ASD encompasses a wide range of debilitating spinal abnormalities. Concurrently, obesity is on the rise globally and has been shown to influence the outcomes of ASD management. The relationship between obesity and surgical outcomes in ASD has been the focus of recent studies, yielding various results. METHODS: We conducted a comprehensive search of PubMed, Cochrane, and Google Scholar (page 1-20) through June of 2024. The surgical outcomes assessed included post-operative complications, revision rates, wound infections, thromboembolic events, implant-related complications, and non-home discharge. Surgical parameters such as operative time, length of stay (LOS), and estimated blood loss (EBL), as well as functional outcomes like the Oswestry Disability Index (ODI) and pain scores were analyzed. RESULTS: Nine studies met inclusion criteria. Non-obese patients exhibited a lower rate of implant-related complications (OR=0.25; 95% CI: 0.12-0.52, P=0.0002) and non-home discharge (OR=0.52; 95% CI: 0.32-0.84, P=0.007). Additionally, non-obese patients had reduced LOS (MD=-0.29; 95% CI: -0.53 - -0.05, P=0.02) and EBL (SMD=-0.68; 95% CI: -1.19 - -0.18, P=0.008). No statistically significant differences were observed for the remaining outcomes. CONCLUSION: Non-obese patients undergoing ASD corrective surgery are associated with fewer implant-related complications, a lower EBL, shorter LOS, and a higher likelihood of being discharged home compared to their obese counterparts.

Postoperative Delirium Following Posterior Lumbar Spinal Fusion: Epidemiology, Risk Factors, and Associated Complications.

BACKGROUND: Postoperative delirium (POD) is frequently reported in the elderly after major surgery. Several risk factors have been identified, including age, surgical complexity, and comorbidities. METHODS: Posterior lumbar fusion patients were identified using PearlDiver and filtered into two cohorts based on presence or absence of POD within 7 days of surgery. Epidemiological analyses were performed to examine trends in POD by age and year. Comparative analyses were performed on patient demographics and baseline cognitive status. After matching by age, sex, and comorbidities, electrolyte disturbances and 90-day postoperative complications were analyzed. RESULTS: Among 476,482 no POD and 2,591 POD patients, mean age was 60.90 years, 57.6% were female, and mean CCI was 1.78. POD patients frequently had baseline cognitive impairment (p<0.001). Incidence of POD decreased from 0.7% in 2010 to 0.4% in 2022 (p<0.001) and increased with increasing patient age (p<0.001). POD patients had higher length of stay (12 vs 6 days, p<0.001) and 90-day costs ($20,605 vs $17,849, p<0.001). After matching, POD patients had higher hypernatremia (5.8% vs 3.5%, p=0.001) and hypocalcemia (5.0% vs 3.5%, p=0.026). POD patients had higher 90-day postoperative complications (p<0.05) than no POD patients. CONCLUSION: Nearly 0.5% of patients who underwent posterior spinal fusion between 2010-2022 developed delirium, although incidence rates have decreased over time. POD was common in elderly patients with electrolyte disturbances who underwent multi-level fusions. Patients suffering from POD had higher rates of 90-day postoperative complications. Ongoing efforts to deliver interventions to mitigate the consequences of POD among spine surgery patients are warranted.

Alignment in motion: Fall risk in spine patients and the effect of vision, support surface, and adaptation on the cone of economy.

Background: Several assessment tools have been developed to estimate a patient's likelihood risk of falling. None of these measures estimate the contributions of the visual, vestibular, and somatosensory systems to fall risk, especially in patients with degenerative lumbar spine disease. Methods: Degenerative lumbar spine patients with radiculopathy (LD) and healthy subjects who were 35-70 years old without spine complaints were recruited. Patient reported outcome measures (PROMs) were collected prior to testing. Fall risk assessment was completed using Computer Dynamic Posturography (CDP), a computer-controlled balance machine that allows cone of economy (CoE) and cone of pressure (CoP) measurements. All patients completed Sensory Organization Tests (SOT) which include normal and perturbed stability, both with and without visual cues. Results: In total, 43 spine patients and 12 healthy controls were included, with mean age 57.8 years, 39.5% females, and mean BMI of 29.3 kg/m2. Nearly all CoE and most CoP dimensions were found to be larger in LD patients compared to controls across nearly all subtests (p<.05), with the largest dimensions generally observed in the surrounding and support sway testing condition. In LD patients, ODI and PROMIS Pain Interference were negatively correlated with CoE and CoP measurements (p<.05). Conclusions: In this prospective study, body sway was assessed as a function of CoE and CoP using the CDP system and was found to be elevated in spine patients, especially when they experienced increasing levels of visual and vestibular stimulation. The ability to identify the primary drivers of balance disorders is essential in spine patients and may be helpful in the development of a patient-specific treatment plan, which may in the future aid with fall-prevention initiatives.

Epidemiology of Lumbar Spine Fractures: Twenty-Year Assessment of Nationwide Emergency Department Visit Data.

BACKGROUND: Lumbar spine fractures are common injuries associated with substantial morbidity for patients and socioeconomic burden. This study sought to epidemiologically analyze lumbar spine fractures by mechanism of injury and identify temporal trends in patient demographics and disposition, which few studies have previously evaluated. MATERIALS AND METHODS: A retrospective analysis was done of the US National Electronic Injury Surveillance System (NEISS) database between 2003 and 2022. The sample contained all patients 2 to 101 years old with product-related lumbar fractures presenting to participating institutions' emergency departments. A total of 15,196 unweighted injuries (642,979 weighted injuries) were recorded. RESULTS: Overall, there was a 20-year incidence rate of 10.14 cases per 100,000 person-years with a 2-fold increase in fracture incidence. Females were more prone to lumbar fracture than males (P=.032). Injuries primarily stemmed from a fall (76.6%). The incidence of lumbar fracture increased most significantly in older patients, with patients 80 years and older showing the greatest annual increase (ß=8.771, R2=0.7439, P<.001) and patients 60 to 69 years showing the greatest percent increase with a 3.24-fold increase in incidence. Most (58.9%) of the fractures occurred at home. Females were more often injured at home compared with males (P<.001), who more often sustained lumbar fractures during recreational or athletic activity (P<.001). All patients older than 40 years showed at least a doubling in incidence rate of lumbar fracture between 2003 and 2022. CONCLUSION: These data demonstrate the pressing need to address poor bone health in the aging population, shown here to have an increasing fracture burden. [Orthopedics. 202x;4x(x):xx-xx.].

Spinal deformity surgery in Scheuermann's kyphosis versus adolescent idiopathic scoliosis: meta-analysis of complications and clinical outcomes.

BACKGROUND: Surgical management of adolescent idiopathic scoliosis (AIS) and Scheuermann's kyphosis (SK) may be associated with several complications including extended length of stay and unplanned reoperations. Several studies have previously compared postoperative complications and functional outcomes for AIS and SK patients with mixed results. However, a meta-analysis compiling the literature on this topic is lacking. METHODS: Following the PRISMA guidelines, PubMed, Cochrane, and Google Scholar (pages 1-20) were accessed and explored until April 2024. The extracted data consisted of complications (overall and surgical-site infections [SSI]), readmissions, reoperations, and Scoliosis Research Society-22 (SRS-22) score. Mean differences (MD) with 95% CI were used for continuous data and odds ratio (OR) was utilized for dichotomous data were calculated across studies. RESULTS: Seven retrospective articles were included in the meta-analysis, including 4866 patients, with 399 in the SK group and 4467 in the AIS group. SK patients were found to have statistically significantly higher rates of overall complications (OR = 5.41; 95% CI 3.69-7.93, p < .001), SSI (OR = 11.30; 95% CI 6.14-20.82, p < .001), readmissions (OR = 2.81; 95% CI 1.21-6.53, p = 0.02), and reoperations (OR = 7.40; 95% CI 4.76-11.51, p < .001) than AIS patients. However, they had similar SRS-22 scores postoperatively (MD = -0.06; 95% CI -0.16 to 0.04, p = 0.26) despite the SK group having lower SRS-22 scores preoperatively (MD = -0.30; 95% CI -0.42 to -0.18, p < .001). CONCLUSION: In this meta-analysis of studies comparing spinal deformity surgery outcomes in AIS and SK patients, SK was associated with more complications, readmissions, and reoperations. SK did have equivalent SRS-22 scores postoperatively to AIS patients, highlighting the benefit of surgical treatment despite higher complication rates. This data may help inform healthcare institutions, payors, and quality monitoring organizations who examine outcomes of pediatric and adult spinal deformity surgery.

The Epidemiology of Recreation-Related Cervical and Thoracic Fractures.

CONTEXT: Recreational activities are frequently associated with spinal fracture, yet contemporary characterization of sports-related cervical and thoracic fracture is lacking. PURPOSE: To characterize cervical and thoracic fractures associated with recreational activities. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: The National Electronic Injury Surveillance System (NEISS) database OUTCOME MEASURE AND COMPARISONS: Recreation-related cervical and thoracic fracture incidence rates per year, stratified by age and sex. Common causative activities were established by demographics. METHODS: The NEISS database was queried to identify patients with recreation-related cervical fractures between 2003 and 2022 and recreation-related thoracic fractures between 2003 and 2022 in patients aged >2 years-old. United States Census data was utilized to generate incidence rates per year. Data was stratified by demographic variables to assess the impact of age and sex on incidence and causative activity. RESULTS: Between 2003 and 2022, an estimated 13,823 recreation-related cervical fractures occurred with an average annual incidence of 2.20±0.35 per 1 million person-years, while 24,236 estimated recreation-related thoracic fractures occurred from 2003 to 2022 with an average incidence of 3.85±1.26. Males experienced a 3.51 times higher (95% CI 3.38-3.66) rate of cervical fracture, but thoracic fracture rates were similar between sexes. Individuals under 18 experienced a 2.15 times higher rate of thoracic fractures than those aged 18-64 (95% CI 1.85-2.50) and 1.93 times higher rate than those over 65 (95% CI 1.68-2.22). Recreation-related cervical fracture rates in individuals 18-64 was 1.186 (95% CI 1.14-1.23) times higher than those under 18 and rates in those under 18 were 1.15 (95% CI 1.09-1.22) times higher than those over 65. Football (26.6%), horseback riding (19.7%), and skiing (8.35%) were the primary causes of cervical fractures, and horseback riding (46.8%), football (11.2%), and skiing (10.3%) primarily caused thoracic fractures. Cervical fractures resulted primarily from football in males (24.7%) and horseback riding in females (44.0%). Horseback riding primarily caused thoracic fractures in both sexes (males=21.5%, females=74.7%). Football led causative activities for individuals under 18 (Cervical=42.4%, Thoracic=40.7%), while horseback riding dominated among those aged 18-64 (26.7%, 56.7%) and over 65 (52.8%, 67.9%). CONCLUSIONS: This investigation revealed epidemiological trends in cervical and thoracic spinal fractures and underscore the need for targeted preventive measures and safety interventions to mitigate the burden of these fractures particularly in horseback riding and American football.

The Conceptualization and Derivation of the Cervical Lordosis Distribution Index.

SUMMARY OF BACKGROUND DATA: Yilgor et al developed the lumbar Lordosis Distribution Index to individualize the pelvic mismatch to each patient's pelvic incidence. The cervical lordosis distribution in relation to its apex has not been characterized. OBJECTIVE: Tailor correction of cervical deformity by incorporating the cervical apex into a distribution index(CLDI) to maximize clinical outcomes while lowering rates of junctional failure. STUDY DESIGN/SETTING: Retrospective cohort. METHODS: CD patients with complete 2Y data were included. Optimal outcome is defined by no DJF, and meeting Virk et al Good Clinical Outcome Criteria:[Meeting 2 of 3: 1)an NDI<20 or meeting MCID, 2)mJOA>=14, 3)an NRS-Neck<=5 or improved by 2 or more points]. C2-T2 lordosis was divided into cranial (C2 to apex) and caudal (apex to T2) arches postoperatively. A cervical lordosis distribution index(CLDI) was developed by dividing the cranial lordotic arch(C2 to apex) by the total segment(C2-T2) and multiplying by 100. Cross-tabulations developed categories for CLDI producing the highest chi-square values for achieving Optimal Outcome at two years and outcomes were assessed by multivariable analysis controlling for significant confounders. RESULTS: 84 CD patients were included. Cervical apex distribution postoperatively was: 1% C3, 42% C4, 30% C5, 27% C6. Mean cervical LDI was 117±138. Mean cranial lordosis was 23.2±12.5°. Using cross-tabulations, a CLDI between 70 and 90 was defined as 'Aligned'. Chi-square test revealed significant differences among CLDI categories for DJK, DJF, Good Clinical Outcome, and Optimal Outcome(all P<0.05). Patients aligned in CLDI were less likely to develop DJK(OR: 0.1, [0.01-0.88]), more like to achieve GCO (OR: 3.9, [1.2-13.2]) and Optimal Outcome (OR: 7.9, [2.1-29.3] at two years. Patients aligned in CLDI developed DJF at a rate of 0%. CONCLUSION: The cervical lordosis distribution index, classified through the cranial segment, takes each unique cervical apex into account and tailors correction to the patient in order to better achieve good clinical outcomes and minimize catastrophic complications following cervical deformity surgery. LEVEL OF EVIDENCE: III.

Large Language Model Prompting Techniques for Advancement in Clinical Medicine.

Large Language Models (LLMs have the potential to revolutionize clinical medicine by enhancing healthcare access, diagnosis, surgical planning, and education. However, their utilization requires careful, prompt engineering to mitigate challenges like hallucinations and biases. Proper utilization of LLMs involves understanding foundational concepts such as tokenization, embeddings, and attention mechanisms, alongside strategic prompting techniques to ensure accurate outputs. For innovative healthcare solutions, it is essential to maintain ongoing collaboration between AI technology and medical professionals. Ethical considerations, including data security and bias mitigation, are critical to their application. By leveraging LLMs as supplementary resources in research and education, we can enhance learning and support knowledge-based inquiries, ultimately advancing the quality and accessibility of medical care. Continued research and development are necessary to fully realize the potential of LLMs in transforming healthcare.

Evaluating the impact of multiple sclerosis on 2 year postoperative outcomes following long fusion for adult spinal deformity: a propensity score-matched analysis.

STUDY DESIGN: Retrospective cohort study. PURPOSE: The impact of neuromuscular disorders such as multiple sclerosis (MS) on outcomes following long segment fusion is underreported. This study evaluates the impact of MS on two-year (2Y) postoperative complications and revisions following ≥ 4-level fusion for adult spinal deformity (ASD). METHODS: Patients undergoing ≥ 4-level fusion for ASD were identified from a statewide database. Patients with a baseline diagnosis of MS were also identified. Patients with infectious/traumatic/neoplastic indications were excluded. Subjects were 1:1 propensity score-matched (MS to no-MS) based on age, sex and race and compared for rates of 2Y postoperative complications and reoperations. Logistic regression models were utilized to determine risk factors for adverse outcomes at 2Y. RESULTS: 86 patients were included overall (n = 43 per group). Age, sex, and race were comparable between groups (p > 0.05). MS patients incurred higher charges for their surgical visit ($125,906 vs. $84,006, p = 0.007) with similar LOS (8.1 vs. 5.3 days, p > 0.05). MS patients experienced comparable rates of overall medical complications (30.1% vs. 25.6%) and surgical complications (34.9% vs. 30.2%); p > 0.05. MS patients had similar rates of 2Y revisions (16.3% vs. 9.3%, p = 0.333). MS was not associated with medical, surgical, or overall complications or revisions at minimum 2Y follow-up. CONCLUSION: Patients with MS experienced similar postoperative course compared to those without MS following ≥ 4-level fusion for ASD. This data supports the findings of multiple previously published case series' that long segment fusions for ASD can be performed relatively safely in patients with MS.

Intraoperative fluid management in adult spinal deformity surgery: variation analysis and association with outcomes.

PURPOSE: To evaluate the variability in intraoperative fluid management during adult spinal deformity (ASD) surgery, and analyze the association with complications, intensive care unit (ICU) requirement, and length of hospital stay (LOS). METHODS: Multicenter comparative cohort study. Patients ≥ 18 years old and with ASD were included. Intraoperative intravenous (IV) fluid data were collected including: crystalloids, colloids, crystalloid/colloid ratio (C/C), total IV fluid (tIVF, ml), normalized total IV fluid (nIVF, ml/kg/h), input/output ratio (IOR), input-output difference (IOD), and normalized input-output difference (nIOD, ml/kg/h). Data from different centers were compared for variability analysis, and fluid parameters were analyzed for possible associations with the outcomes. RESULTS: Seven hundred ninety-eight patients with a median age of 65.2 were included. Among different surgical centers, tIVF, nIVF, and C/C showed significant variation (p < 0.001 for each) with differences of 4.8-fold, 3.7-fold, and 4.9-fold, respectively. Two hundred ninety-two (36.6%) patients experienced at least one in-hospital complication, and ninety-two (11.5%) were IV fluid related. Univariate analysis showed significant relations for: LOS and tIVF (ρ = 0.221, p < 0.001), IOD (ρ = 0.115, p = 0.001) and IOR (ρ = -0.138, p < 0.001); IV fluid-related complications and tIVF (p = 0.049); ICU stay and tIVF, nIVF, IOD and nIOD (p < 0.001 each); extended ICU stay and tIVF (p < 0.001), nIVF (p = 0.010) and IOD (p < 0.001). Multivariate analysis controlling for confounders showed significant relations for: LOS and tIVF (p < 0.001) and nIVF (p = 0.003); ICU stay and IOR (p = 0.002), extended ICU stay and tIVF (p = 0.004). CONCLUSION: Significant variability and lack of standardization in intraoperative IV fluid management exists between different surgical centers. Excessive fluid administration was found to be correlated with negative outcomes. LEVEL OF EVIDENCE: III.

L5-S1 Transforaminal Lumbar Interbody Fusion (TLIF) Is Associated with Increased Revisions Compared to L4-L5 TLIF at Two Years.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Compare outcomes in patients undergoing one-level transforaminal lumbar interbody fusion (TLIF) at L4-S1. BACKGROUND: TLIF is frequently performed at L4-S1 to treat degenerative lumbar pathologies. However, the native alignment and biomechanics differ across L4-L5 and L5-S1, and there is limited data regarding comparative radiographic outcomes. METHODS: Patients who underwent one-level TLIF at L4-L5 or L5-S1 at a single academic institution were identified. Baseline demographics, procedural characteristics, change in postoperative spinopelvic alignment and patient-reported outcome measures (PROMs), and two-year postoperative surgical complications were compared. Multivariate regression analyses, accounting for age, gender, Charlson Comorbidity Index (CCI), and body mass index (BMI), were also performed. RESULTS: Across the 175 included patients, 125 had L4-L5 TLIF and 50 had L5-S1 TLIF. The mean age was 57.8 years, 56.6% were female, mean CCI was 0.9, and mean follow-up was 26.7 months. In the hospital, the two cohorts were not statistically different with regards to EBL and LOS. Two years postoperatively, multivariate linear regression analyses revealed that L5-S1 TLIF achieved 6.0° higher correction in L4-S1 lordosis ( P =0.012) than L4-L5 TLIF. At the same time, however, L5-S1 TLIF patients experienced significantly higher rates of pseudoarthrosis (8.0% vs 1.6%, P =0.036) and subsequent spine surgery (18.0% vs. 7.2%, P =0.034), specifically for pseudoarthrosis (6.0% vs. 0.0%, P =0.006), with this cohort having 8.7 times higher odds of subsequent spine surgery for pseudoarthrosis ( P =0.015) than L4-L5 TLIF patients on multivariate logistic analyses. PROMs, on the other hand, were not different across the two cohorts. CONCLUSIONS: Although L5-S1 TLIF yielded good radiographic correction, it was associated with higher rates of subsequent spine surgery for pseudoarthrosis compared to L4-L5 TLIF. These findings may be related to differences in native segmental alignment and biomechanics across the L4-L5 and L5-S1 motion segments and are important to consider during surgical planning. LEVEL OF EVIDENCE: IV.

The Importance of Alignment in the Management of Thoracolumbar Trauma.

Spinal injuries occur in 3% of all trauma patients, most commonly in males, and often due to high-velocity impact followed by abrupt deceleration. The most affected region following spinal trauma is the thoracolumbar junction due to the anterior center of gravity at T12-L1 vertebral level and the relatively stiff thoracic spine uniting with the mobile lumbar spine. Many classifications exist to guide the choice of operative versus non-operative management of traumatic injuries at this site. However, the current classifications do not consider the segmental alignment of the spine - an aspect which has been shown to improve quality of life in non-traumatic post-operative spinal patients. Ignoring this aspect of thoracolumbar management often contributes to the development of post-traumatic malalignment and other complications. This review recommends that a new or modified classification system accounts for sagittal segmental alignment factors, including the injured vertebra's level, the number of affected adjacent levels, imaging techniques with better specificity and sensitivity, and assessment for osteoporosis. Case studies are included to demonstrate the importance of segmental sagittal alignment and the vertebral level on patient outcomes.

Electrolyte Disturbances and Repletion in Orthopaedic and Spine Surgery Patients.

Electrolyte derangement, defined as disorders of clinically impactful physiologic ions such as potassium, sodium, calcium, magnesium, and phosphate, has a variety of clinical manifestations. These electrolytes have narrow windows of normal in vivo concentration before neurologic, cardiac, renal, or gastrointestinal consequences occur. Perioperative disturbances in electrolyte concentration can lead to increased morbidity and mortality, longer length of stay, and higher rates of short and medium-term readmission in orthopaedic and spine surgery postoperatively. To prevent electrolyte related complications, careful monitoring and repletion of at-risk patients must be undertaken. A systematic approach to repletion allows for a safe and efficacious treatment of these disorders.

Incremental Increase in Hospital Length of Stay Due to Complications of Surgery for Adult Spinal Deformity.

STUDY DESIGN: Retrospective Cohort Study. OBJECTIVES: Length of Stay (LOS) and resource utilization are of primary importance for hospital administration. This study aimed to understand the incremental effect of having a specific complication on LOS among ASD patients. METHODS: A retrospective examination of prospective multicenter data utilized patients without a complication prior to discharge to develop a patient-adjusted and surgery-adjusted predictive model of LOS among ASD patients. The model was later applied to patients with at least 1 complication prior to discharge to investigate incremental effect of each identified complication on LOS vs the expected LOS. RESULTS: 571/1494 (38.2%) patients experienced at least 1 complication before discharge with a median LOS of 7 [IQR 5 to 9]. Univariate analysis demonstrated that LOS was significantly affected by patients' demographics (age, CCI, sex, disability, deformity) and surgical strategy (invasiveness, fusion length, posterior MIS fusion, direct decompression, osteotomy severity, IBF use, EBL, ASA, ICU stay, day between stages, Date of Sx). Using patients with at least 1 complication prior discharge and compared to the patient-and-surgery adjusted prediction, having a minor complication increased the expected LOS by 0.9 day(s), a major complication by 3.9 days, and a major complication with reoperation by 6.3 days. CONCLUSION: Complications following surgery for ASD correction have different, but predictable impact on LOS. Some complications requiring minimal intervention are associated with significant and substantial increases in LOS, while complications with significant impact on patient quality of life may have no influence on LOS.

Impact of Segmental Lordosis Restoration During Degenerative Spinal Fusion on Two-Year Adjacent Segment Disease and Revision Rates.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Assess the impact of inadequate correction of L4-S1 lordosis during transforaminal lumber interbody fusion (TLIF) on adjacent segment disease and revision rates. BACKGROUND: Restoring alignment is an important consideration in spinal fusions. Failure to correct to level-specific alignment goals could promote the development of adjacent segment disease. As such, it is crucial to investigate the role of sagittal segmental alignment on clinical outcomes following short segment lumbar fusion. METHODS: Patients who underwent 1- to 3-level transforaminal lumbar interbody fusion (TLIF) and had two-year outcomes data were included in this retrospective cohort study. Segmental lumbar lordosis was assessed in all patients with L3-L4, L4-L5, and L5-S1 constructs. Demographics, radiographic spinopelvic alignment, and complications were compared in a sub-group of patients fused at L4-S1 with adequate (i.e., within 35-45°) and inadequate (i.e., <35°) L4-S1 lordosis. RESULTS: Among the 168 included patients, mean age was 61.7 years, 56.0% were female, and mean follow-up was 32.3 months. Segmental lumbar lordosis did not change significantly after TLIF of L3-L4, L4-L5, or L5-S1 (P>0.05). Two-year postoperatively, 32.7% developed adjacent segment disease and 19.6% underwent revisions. After stratification by adequate (N=15) or inadequate (N=54) restoration of L4-S1 lordosis following initial TLIF surgery, adequately-restored patients had higher preoperative L4-S1 lordosis (Adequately-Restored=39.3° vs Inadequately-Restored=29.5°, P<0.001) and lower two-year postoperative adjacent segment disease (6.7% vs. 33.3%, P=0.032) and revision (5.7% vs. 25.9%, P=0.l33) rates. Adjacent segment disease patients had higher implant-related complications (Adjacent Segment Disease=36.8% vs No Adjacent Segment Disease=8.0%, P=0.008) and subsequent revisions (61.1% vs. 8.7%, P<0.001). CONCLUSIONS: Adjacent segment disease and revisions after degenerative lumbar spinal fusion are common. In this cohort, suboptimal restoration of L4-S1 lordosis was associated with higher rates of adjacent segment disease and subsequent revisions, thus highlighting the importance of restoring sagittal alignment in degenerative spine surgery. LEVEL OF EVIDENCE: III.

Crossing the Cervicothoracic Junction: A Biomechanical Investigation of C7 vs T1 Caudal Selection's Effect on Adjacent Segment Motion in Posterior Cervical Fusion.

STUDY DESIGN: Biomechanical Study. OBJECTIVE: This study aims to evaluate the biomechanical adjacent segment effects of multi-level posterior cervical fusion constructs that terminate at C7 compared to those that terminate at T1 in cadaveric specimens. BACKGROUND: The cervicothoracic junction poses unique challenges for spine surgeons. Deciding to terminate multi-level posterior cervical fusion constructs at C7 or extend them across the cervicothoracic junction remains a controversial issue. METHODS: Six cadaveric specimens underwent biomechanical testing in the intact state and after instrumentation with constructs from C3 and terminating at either C7 or T1. Range of motion (ROM) was assessed in flexion-extension, lateral bending, and axial rotation globally and at cranial and caudal adjacent segments. RESULTS: There was a significant decrease in overall flexion/extension by both C7 (-35.5°, P=0.002) and T1 (-39.8°, P=0.002) instrumentation compared to the intact spine. T1 instrumentation had significantly lower (-4.3°, P=0.008) flexion/extension ROM compared to C7 instrumentation. There were significant decreases in axial rotation by both C7 (-31.4°, P=0.009) and T1 (-36.8°, P=0.009) instrumentation compared to the intact spine, but no significant differences were observed between the two. There were also significant decreases in lateral bending by both C7 (-27.9°, P=0.022) and T1 (-33.7°, P=0.022) instrumentation compared to the intact spine, but no significant differences were observed between the two. No significant differences were observed in ROM at cranial or caudal adjacent segments between constructs terminating at C7 and those extending to T1. CONCLUSION: This biomechanical investigation demonstrates that constructs that cross the cervicothoracic junction experience less overall spinal motion in flexion-extension compared to those that terminate at C7. However, contrary to prior studies there is no difference in cranial and caudal adjacent segment motion. Surgeons should make clinical decisions regarding the caudal extent of fusion in multi-level posterior cervical fusions without major concerns about adjacent segment motion.

Lumbar Spondylolisthesis Grading: Current Standards and Important Factors to Consider for Management.

Spondylolisthesis is a common condition with a prevalence of 4-6% in childhood and 5-10% in adulthood. The Meyerding Classification, developed in 1932, assigns grades (I to V) based on the degree of slippage observed on standing, neutral lateral lumbar radiographs. Despite its historical significance and reliability, more factors should be evaluated to predict spondylolisthesis progression, especially in low-grade cases. The manuscript highlights areas for improvement in spondylolisthesis classification, emphasizing the need for considering factors beyond vertebral slippage. Factors such as global and segmental alignment, pelvic incidence, overhang, the number of affected levels, and the use of lateral flexion-extension radiographs to assess for stability using the kyphotic angle and slippage degree are identified as crucial in predicting progression and determining effective management strategies.