Complications in Patients Undergoing Spinal Fusion After THA.

INTRODUCTION: Patients with lumbar spine and hip disorders may, during the course of their treatment, undergo spinal fusion and THA. There is disagreement among prior studies regarding whether patients who undergo THA and spinal fusion are at increased risk of THA dislocation and other hip-related complications. QUESTIONS / PURPOSES: Is short or long spinal fusion associated with an increased rate of postoperative complications in patients who underwent a prior THA? PATIENTS AND METHODS: A retrospective study of New York State's Department of Health database (SPARCS) was performed. SPARCS has a unique identification code for each patient, allowing investigators to track the patient across multiple admissions. The SPARCS dataset spans visit data of patients of all ages and races across urban and rural locations. The SPARCs dataset encompasses all facilities covered under New York State Article 28 and uses measures to further representative reporting of data concerning all races. Owing to the nature of the SPARCS dataset, we are unable to comment on data leakage, as there is no way to discern between a patient who does not subsequently seek care and a patient who seeks care outside New York State. ICD-9-Clinical Modification codes identified adult patients who underwent elective THA from 2009 to 2011. Patients who had subsequent spinal fusion (short: 2-3 levels, or long: ≥ 4 levels) with a diagnosis of adult idiopathic scoliosis or degenerative disc disease were identified. Forty-nine thousand nine hundred twenty patients met the inclusion criteria of the study. In our inclusion and exclusion criteria, there was no variation with respect to the distribution of sex and race across the three groups of interest. Patients who underwent a spinal procedure (short versus long fusion) had comparable age. However, patients who did not undergo a spinal procedure were older than patients who had short fusion (65 ± 12.4 years versus 63 ± 10.7 years; p < 0.001). Multivariate binary logistic regression models that controlled for age, sex, and Deyo/Charlson scores were used to investigate the association between spinal fusion and THA revisions, postoperative dislocation, contralateral THAs, and total surgical complications to the end of 2013. A total of 49,920 patients who had THAs were included in one of three groups (no subsequent spinal fusion: n = 49,209; short fusion: n = 478; long fusion: n = 233). RESULTS: Regression models revealed that short and long spinal fusions were associated with increased odds for hip dislocation, with associated odds ratios (ORs) of 2.2 (95% CI, 1.4-3.6; p = 0.002), and 4.4 (95% CI, 2.7-7.3; p < 0.001), respectively. Patients who underwent THA and spinal surgery also had an increased odds for THA revision, with ORs of 2.0 (95% CI, 1.4-2.8; p < 0.001) and 3.2 (95% CI, 2.1-4.8; p < 0.001) for short and long fusion, respectively. However, spinal fusions were not associated with contralateral THAs. Further, short and long spinal fusions were associated with increased surgical complication rates (OR = 2.8, 95% CI, 2.1-3.8, p < 0.001; OR = 5.3, 95% CI, 3.8-7.4, p < 0.001, respectively). CONCLUSION: We showed that spinal fusion in adults is associated with an increased frequency of complications and revisions in patients who have had a prior THA. Specifically, patients who had a long spinal fusion after THA had 340% higher odds of experiencing a hip dislocation and 220% higher odds of having to undergo a revision THA. Further research is necessary to determine whether this relationship is associated with the surgical order, or whether more patient-specific surgical goals of revision THA should be developed for patients with a spinal deformity. LEVEL OF EVIDENCE: Level III, therapeutic study.

Ion-binding properties of a K+ channel selectivity filter in different conformations.

K(+) channels are membrane proteins that selectively conduct K(+) ions across lipid bilayers. Many voltage-gated K(+) (KV) channels contain two gates, one at the bundle crossing on the intracellular side of the membrane and another in the selectivity filter. The gate at the bundle crossing is responsible for channel opening in response to a voltage stimulus, whereas the gate at the selectivity filter is responsible for C-type inactivation. Together, these regions determine when the channel conducts ions. The K(+) channel from Streptomyces lividians (KcsA) undergoes an inactivation process that is functionally similar to KV channels, which has led to its use as a practical system to study inactivation. Crystal structures of KcsA channels with an open intracellular gate revealed a selectivity filter in a constricted conformation similar to the structure observed in closed KcsA containing only Na(+) or low [K(+)]. However, recent work using a semisynthetic channel that is unable to adopt a constricted filter but inactivates like WT channels challenges this idea. In this study, we measured the equilibrium ion-binding properties of channels with conductive, inactivated, and constricted filters using isothermal titration calorimetry (ITC). EPR spectroscopy was used to determine the state of the intracellular gate of the channel, which we found can depend on the presence or absence of a lipid bilayer. Overall, we discovered that K(+) ion binding to channels with an inactivated or conductive selectivity filter is different from K(+) ion binding to channels with a constricted filter, suggesting that the structures of these channels are different.

Structure of a membrane-embedded prenyltransferase homologous to UBIAD1.

Membrane-embedded prenyltransferases from the UbiA family catalyze the Mg2+-dependent transfer of a hydrophobic polyprenyl chain onto a variety of acceptor molecules and are involved in the synthesis of molecules that mediate electron transport, including Vitamin K and Coenzyme Q. In humans, missense mutations to the protein UbiA prenyltransferase domain-containing 1 (UBIAD1) are responsible for Schnyder crystalline corneal dystrophy, which is a genetic disease that causes blindness. Mechanistic understanding of this family of enzymes has been hampered by a lack of three-dimensional structures. We have solved structures of a UBIAD1 homolog from Archaeoglobus fulgidus, AfUbiA, in an unliganded form and bound to Mg2+ and two different isoprenyl diphosphates. Functional assays on MenA, a UbiA family member from E. coli, verified the importance of residues involved in Mg2+ and substrate binding. The structural and functional studies led us to propose a mechanism for the prenyl transfer reaction. Disease-causing mutations in UBIAD1 are clustered around the active site in AfUbiA, suggesting the mechanism of catalysis is conserved between the two homologs.

Ratio of lumbar 3-column osteotomy closure: patient-specific deformity characteristics and level of resection impact correction of truncal versus pelvic compensation.

PURPOSE: The resection point of a lumbar three-column osteotomy (3CO) creates separation of the spino-pelvic complex. This study investigates the impact of patients' baseline deformity and level of 3CO resection on the distribution of correction between the trunk and the pelvis following osteotomy closure. METHODS: Patients who underwent single lumbar 3CO, upper instrumented vertebra (UIV) T1-T10, and 6 month follow-up were included. The truncal and pelvic closures were calculated based on the vertebrae adjacent to the osteotomy level and the impact of radiographic parameters and level of 3CO on the closures were analyzed. RESULTS: 113 patients were included. Patients who experienced more pelvic correction had significantly higher Pelvic Tilt and lower Sagittal Vertical Axis at baseline. Patients who underwent more caudal osteotomies with higher pelvic compensation with modest SVA sustained more pelvic correction. CONCLUSIONS: The osteotomy closure is driven by patient's specific deformity. More caudal osteotomy level leads to greater pelvic tilt improvement. LEVEL OF EVIDENCE: III.

Structural insights into the N-terminal GIY-YIG endonuclease activity of Arabidopsis glutaredoxin AtGRXS16 in chloroplasts.

Glutaredoxins (Grxs) have been identified across taxa as important mediators in various physiological functions. A chloroplastic monothiol glutaredoxin, AtGRXS16 from Arabidopsis thaliana, comprises two distinct functional domains, an N-terminal domain (NTD) with GlyIleTyr-TyrIleGly (GIY-YIG) endonuclease motif and a C-terminal Grx module, to coordinate redox regulation and DNA cleavage in chloroplasts. Structural determination of AtGRXS16-NTD showed that it possesses a GIY-YIG endonuclease fold, but the critical residues for the nuclease activity are different from typical GIY-YIG endonucleases. AtGRXS16-NTD was able to cleave λDNA and chloroplast genomic DNA, and the nuclease activity was significantly reduced in AtGRXS16. Functional analysis indicated that AtGRXS16-NTD could inhibit the ability of AtGRXS16 to suppress the sensitivity of yeast grx5 cells to oxidative stress; however, the C-terminal Grx domain itself and AtGRXS16 with a Cys123Ser mutation were active in these cells and able to functionally complement a Grx5 deficiency in yeast. Furthermore, the two functional domains were shown to be negatively regulated through the formation of an intramolecular disulfide bond. These findings unravel a manner of regulation for Grxs and provide insights into the mechanistic link between redox regulation and DNA metabolism in chloroplasts.

Impact of Joint Position and Joint Morphology on Assessment of Thumb Metacarpophalangeal Joint Radial Collateral Ligament Integrity.

PURPOSE: A 2-part biomechanical study was constructed to test the hypothesis that coronal morphology of the thumb metacarpophalangeal joint impacts the assessment of instability in the context of radial collateral ligament (RCL) injury. METHODS: Fourteen cadaveric thumbs were disarticulated at the carpometacarpal joint. Four observers measured the radius of curvature of the metacarpal (MC) heads. In a custom jig, a micrometer was used to measure the RCL length as each thumb was put through a flexion and/or extension arc under a 200 g ulnar deviation load. Strain was calculated at maximal hyperextension, 0°, 15°, 30°, 45°, and maximal flexion. Radial instability was measured with a goniometer under 45 N stress. The RCL was then divided and measurements were repeated. Analysis of variance and Pearson correlation metrics were used. RESULTS: The RCL strain notably increased from 0° to 30° and 45° of flexion. With an intact RCL, the radial deviation was 15° at 0° of flexion, 18° at 15°, 17° at 30°, 16° at 45°, and 14° at maximal flexion. With a divided RCL, instability was greatest at 30° of flexion with 31° of deviation. The mean radius of curvature of the MC head was 19 ± 4 mm. Radial instability was inversely correlated with the radius of curvature to a considerable degree only in divided RCL specimens, and only at 0° and 15° of flexion. CONCLUSIONS: The RCL contributes most to the radial stability of the joint at flexion positions greater than 30°. The results suggest that flatter MC heads contribute to stability when the RCL is ruptured and the joint is tested at 0° to 15° of metacarpophalangeal flexion. CLINICAL RELEVANCE: The thumb MC joint should be examined for RCL instability in at least 30° of flexion.

Osteotomies in the treatment of spinal deformities: indications, classification, and surgical planning.

The surgical treatment of adult spinal deformity has been shown to offer superior clinical and radiographic outcomes compared with nonoperative approaches; furthermore, osteotomies are increasingly applied for treating spinal deformities. Establishing a plan for a patient suffering from marked spinal deformity is a matter of consideration of certain radiographic parameters which correlate with health-related quality of life scores, adherence to consistent principles of alignment and established formulas, and selecting the appropriate osteotomies. This is a review of the most recent work on vertebral osteotomies and includes a summary of a systematic and anatomically based osteotomy classification. A universal classification will facilitate communication, standardize outcomes research, and establish a framework upon which indications can be properly studied and described. Ongoing multicenter collaboration is certain to drive a more evidence-based approach to the complex clinical scenarios of patients suffering from spinal deformity.

[Long-term Survival in Hospitalized Patients with Lung Cancer among Peasants 
in the Coal-producing Area in Eastern Yunnan, China].

BACKGROUND: Xuanwei and Fuyuan are rural counties, located in the late Permian coal poly area of eastern Yunnan and western Guizhou, where lung cancer mortality rates are among the highest in the China, with similarity for both men and women, younger age at diagnosis and death, and higher in rural areas than in urban areas. In this paper, long-term follow-up of lung cancer cases in local peasants was conducted to observe their survival prognosis and its influencing factors. METHODS: Data of patients diagnosed with lung cancer from January 2005 to June 2011, who had lived in Xuanwei and Fuyuan counties for many years, were collected from 20 hospitals at the local provincial, municipal and county levels. To estimate survival outcomes, individuals were followed up until the end of 2021. The 5-year, 10-year and 15-year survival rates were estimated using the Kaplan-Meier method. Survival differences were examined with Kaplan-Meier curves and Cox proportional hazards models. RESULTS: A total of 3,017 cases were effectively followed up (2,537 peasants and 480 non-peasants). The median age at diagnosis was 57 years, and the median follow-up time was 122 months. During the follow-up period, 2,493 cases (82.6%) died. The distribution of cases by clinical stage was as follows: stage I (3.7%), stage II (6.7%), stage III (15.8%), stage IV (21.1%) and unknown stage (52.7%). Treatment at the provincial, municipal and county-level hospitals accounted for 32.5%, 22.2% and 45.3%, respectively, and surgical treatment was performed in 23.3% of cases. The median survival time was 15.4 months (95%CI: 13.9-16.1), and the 5-year, 10-year and 15-year overall survival rates were 19.5% (95%CI: 18.0%-21.1%), 7.7% (95%CI: 6.5%-8.8%) and 2.0% (95%CI: 0.8%-3.9%), respectively. Peasants with lung cancer had a lower median age at diagnosis, higher proportion residing in remote rural areas, and higher use of bituminous coal as a household fuel. They also have a lower proportion of early-stage cases, treatment at provincial or municipal hospitals, and surgical treatment, leading to poorer survival outcomes (HR=1.57). Even when considering factors such as gender, age, residential location, clinical stage at diagnosis, histological type, hospital level of service, and surgical intervention, peasants still exhibit a survival disadvantage. Multivariable Cox model analysis comparing peasants and non-peasants reveals that surgical intervention, tumor-node-metastasis (TNM) stage, and hospital level of service are common factors influencing survival prognosis, while the use of bituminous coal as a household fuel, hospital level of service and adenocarcinoma (compared to squamous cell carcinoma) are independent prognostic factors for lung cancer survival among peasants. CONCLUSIONS: The lower lung cancer survival rate among peasants is associated with their lower socioeconomic status, lower proportion of early-stage diagnoses, lower proportion of surgical interventions, and treatment at provincial-level hospitals. Furthermore, the impact of other factors such as high-risk exposure to bituminous coal pollution on survival prognosis requires further investigation.

Differential activation mechanisms of lipid GPCRs by lysophosphatidic acid and sphingosine 1-phosphate.

Lysophospholipids are bioactive lipids and can signal through G-protein-coupled receptors (GPCRs). The best studied lysophospholipids are lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P). The mechanisms of lysophospholipid recognition by an active GPCR, and the activations of lysophospholipid GPCR-G-protein complexes remain unclear. Here we report single-particle cryo-EM structures of human S1P receptor 1 (S1P1) and heterotrimeric Gi complexes formed with bound S1P or the multiple sclerosis (MS) treatment drug Siponimod, as well as human LPA receptor 1 (LPA1) and Gi complexes in the presence of LPA. Our structural and functional data provide insights into how LPA and S1P adopt different conformations to interact with their cognate GPCRs, the selectivity of the homologous lipid GPCRs for S1P versus LPA, and the different activation mechanisms of these GPCRs by LPA and S1P. Our studies also reveal specific optimization strategies to improve the MS-treating S1P1-targeting drugs.

Adult-onset Still's disease complicated with hemophagocytic syndrome.

Hemophagocytic syndrome (HS) that occurs in the course of adult-onset Stills disease (AOSD) has been reported only rarely in the literature. HS and AOSD share overlapping clinical and laboratory features, therefore, it is difficult to recognize HS as a complication of AOSD. Here, we report the case of a 46-year old woman with classical features of AOSD. Severe pancytopenia and jaundice associated with extreme hyperferritinemia occurred during high-dose steroid treatment. Bone marrow biopsy showed typical pathological features of hemophagocytosis, which confirmed the coexistence of HS with AOSD. The patient was treated with methylprednisolone pulse therapy of 500 mg/day for 3 days, as recommended in cases of HS complicating AOSD, and her condition improved gradually. During the disease course, extensive studies could not identify any viral infection or other known underlying etiology for the reactive hemophagocytosis. Currently, the patient is in remission on low-dose prednisolone and azathioprine.

Esophageal intramural pseudodiverticulosis complicated with stricture.

We report a rare case of diffuse esophageal intramural pseudodiverticulosis in a 35-year-old man complaining of severe dysphagia and vomiting for several months. The advanced morphological change in the esophagus caused irregular track formation, mimicking an ulcerative lesion on esophagogram. Endoscopic examination revealed an esophageal stricture with intact mucosa. Endoscopic ultrasonography and chest computed tomography showed multiple hyperechoic lesions of unknown nature and multiple air collection sites in the esophageal wall, respectively, making diagnosis difficult. The patient finally received a subtotal esophagectomy because of severe symptoms. The lesion was pathologically proven to be intramural pseudodiverticulosis with marked submucosal fibrosis. Our experience suggests that awareness of this rare pathology and the related image changes will be helpful for early diagnosis and treatment in the future.

Association of heartburn and laryngopharyngeal symptoms with endoscopic reflux esophagitis, smoking, and drinking.

OBJECTIVES: This study was conducted to investigate the association of laryngopharyngeal symptoms and heartburn with endoscopic esophagitis, smoking, and drinking. The clinical importance of the Reflux Symptom Index (RSI) in predicting endoscopic esophagitis was also evaluated. STUDY DESIGN: Case series with planned data collection. SUBJECTS AND METHODS: From November 2006 to February 2007, 156 adults received a whole-body physical check-up. They filled out the RSI questionnaire and were dichotomized into either a "no problem group" or a "possible patients group" according to their scores on the RSI. All subjects received an esophagoscopy. The relationship between RSI score and endoscopic esophagitis, smoking, and drinking was analyzed. RESULTS: Voice change, but not heartburn, was significantly associated with endoscopic reflux esophagitis. Based on the RSI scores, some items in addition to voice change were significantly associated with smoking or drinking but not with endoscopic esophagitis. CONCLUSIONS: While screening patients for reflux esophagitis by using the RSI questionnaire, there is little value in using heartburn to predict endoscopic esophagitis in Taiwanese people. On the other hand, a husky voice might be a good clinical indicator of patients at risk of having reflux esophagitis.

[Public health situation and needs assessment after Wenchuan earthquake in Anxian, Sichuan province].

OBJECTIVE: To explore the public health situation and needs in Anxian after Wenchuan earthquake so as to make an effective strategy for disease control and prevention. METHODS: 69 concentrated settlements with 100 residents were investigated. Probability proportion to size was adopted for sampling of 2200 residents from 687 scattered households (about 440 000 scattered residents). The content of this survey included drinking water, food hygiene, environment sanitation, planning immunity and medical health service, disease surveillance and so on. SPSS 16.0 was used for data analysis, and statistical interpretation was used to describe the results. RESULTS: 90.9% (31/66) resettled residents in Anxian lived in tents, 7.6% (5/66) lived in the movable-plate house, 93.3% (621/666) scattered households lived in tents and 71.9% (446/621) of them lived in tents which were built by residents themselves; the rate of drinking water disinfection in resettlement sites and scattered households were 97.1% (66/68) and 94.6% (650/687); 12.8% scattered residents had mouldy or food; 50% of resettlement sites raised animals; 43.6% (17/39) medical station didn't have bacterin inoculation service; 66.7% (10/15) lacked sufficient disinfection equipment; register rate was 50.0% (33/66) and report rate of symptoms and infectious diseases was 56.1% (37/66). CONCLUSION: There was still some risk of enteric and vector-borne diseases in Anxian, therefore, some tailored measures should be very important.

[Mental health assessment among scattered residents after Wenchuan earthquake in Anxian, Sichuan province].

OBJECTIVE: To explore the mental health status of residents scattered living in Anxian after Wenchuan earthquake so as to provide scientific basis for further mental health intervention. METHODS: A face to face interview was conducted among the scattered residents with designed questionnaire, which had three parts of the physical and emotional reaction, the relax methods and the social care and supports expected. Two-stage probability proportional to size (PPS) sample method was performed to sample 2184 from 0.44 million scattered residents in Anxian. On the basis of statistical description, mental health of different characteristics groups was compared. RESULTS: Three main symptoms of posttraumatic stress disorders in 2184 residents (11.23+/-3.44) were higher than the 103 fire victims in Hunan in 2003 (10.06+/-3.26), three factor scores of SCL-90 (5.76+/-1.74) were higher than normal in 1998 repair mode (n=23 891) (4.72+/-1.44), and the statistical difference was observed (t=10.77, P<0.05; t=706.04, P<0.05). Comparing the mental health of different groups, some significant differences were found by age, gender and education background. CONCLUSION: The earthquake disaster brought prevalent physical and emotional reaction. Elderly people, female, junior students need mental intervention immediately. Therefore, strengthen the mental education and assistance (especially in high risk groups) would be of more significance.

[Survival in Lung Cancer among Female Never-smokers in Rural Xuanwei 
and Fuyuan Counties in Eastern Yunnan Province, China].

BACKGROUND: Lung cancer rates among women in rural Xuanwei and Fuyuan counties in eastern Yunnan province, China, are among the highest in the world, even though almost all women are non-smokers, and they tend to develop lung cancer at a younger age than other locations by roughly 5 yr-10 yr. This study investigated the survival of lung cancer patients among female never-smokers. METHODS: The female never-smokers, who had lived for many years in Xuanwei and Fuyuan counties, with lung cancer newly-diagnosed between July 2006 to March 2010, were followed up through the end of 2016. Age-standardized relative survival for all cases was calculated using local life table. The Kaplan-Meier method and Log-rank test were used to analyze the relationship between the variables and the prognosis in univariate analysis. Cox regression analysis was employed in the multivariate analysis. RESULTS: Among 1,250 total subjects, 1,075 died and the remaining 175 were censored during the follow-up, with a median follow-up period of 69 months (95%CI: 61.9-76.0). Overall, the mean age was (54.8 ±10.9) yr, with variable clinical stages: 3.5% of cases were stage I, 8.7% stage II, 20.7% stage III, 29.7% stage IV, and 37.4% stage unknown. The 645 patients(51.6%) with cyto-histological diagnosis contains 303 with Squamous cell carcinoma, and 231 with adenocarcinoma, 24 with small cell, 43 with other specified type and 39 with unknown histological type. Only 215 (17.2%) patients received surgery, 487 (39.0%) were treated without surgery, and 548 (43.8%) did not receive any specific anticancer therapy. The 5-year observed survival rate and age-standardized relative survival were 8.9% (95%CI: 7.0-10.6), and 10.1% (95%CI: 3.7-20.5) respectively, with a median survival of 13.2 months. The 5-year survival rates were 41.1% for stage I, 22.4% for stage II, 5.3% for stage III, 1.3% for stage IV, 11.2% for missing stage, 17.9% for adenocarcinoma, and 5.6% for squamous cell carcinoma respectively. Surgery significantly improved 5-year survival rate compared with non-surgery (34.8% vs 3.2%, P<0.001). The patients with non-treatment, aged 65 years and older, living in rural areas and farmer with low socioeconomic status had poorer survival, whereas the patients treated in provincial hospitals and chest X-ray screening had better survival. Cox multivariate analysis further showed that stage of tumor-node-metastasis (TNM), treatment status, hospital-level, and X-ray screening were factors correlated with survival. CONCLUSIONS: Patients with lung cancer among female never-smokers in Xuanwei and Fuyuan experience poorer survival, because they are less likely to be diagnosed at early stage, as well as less likely to receive surgery and comprehensive treatment. Furthermore low socioeconomic status and poor health security are also responsible for the low survival.

Spinal Fusion in Parkinson's Disease Patients: A Propensity Score-Matched Analysis With Minimum 2-Year Surveillance.

STUDY DESIGN: Retrospective analysis. OBJECTIVE: To compare outcomes and complication rates between patients with and without Parkinson's disease (PD) patients undergoing surgery for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: There is limited literature evaluating the impact of PD on long-term outcomes after thoracolumbar fusion surgery for ASD. METHODS: Patients admitted from 2009 to 2011 with diagnoses of ASD who underwent any thoracolumbar fusion procedure with a minimum 2-year follow-up surveillance were retrospectively reviewed using New York State's Statewide Planning and Research Cooperative System. A 1:1 propensity score-match by age, Deyo score, and number of fused vertebral levels was conducted before comparing surgical outcomes of patients with ASD with and without PD. Univariate analysis compared demographics, complications, and subsequent revision. Multivariate binary stepwise logistic regression models identified independent predictors of these outcomes (covariates: age, sex, Deyo Index score, and PD diagnosis). RESULTS: A total of 576 propensity score-matched patients were identified (PD: n = 288; no-PD: n = 288), with a mean age of 69.7 years (PD) and 70.2 years (no-PD). Each cohort had comparable distributions of age, sex, race, insurance provider, Deyo score, and number of levels fused (all P > 0.05). Patients with PD incurred higher total charges across ASD surgery-related visits ($187,807 vs. $126,610, P < 0.001), yet rates of medical complications (35.8% PD vs. 34.0% no-PD, P = 0.662) and revision surgery (12.2% vs. 10.8%, P > 0.05) were comparable. Postoperative mortality rates were comparable between PD and no-PD cohorts (2.8% vs. 1.4%, P = 0.243). Logistic regression identified nine-level or higher spinal fusion as a significant predictor for an increase in total complications (odds ratio = 5.64); PD was not associated with increased odds of any adverse outcomes. CONCLUSION: Aside from higher hospital charges incurred, patients with PD experienced comparable overall complication and revision rates to a propensity score-matched patient cohort without PD from the general population undergoing thoracolumbar fusion surgery. These results can support management of concerns and postoperative expectations in this patient cohort. LEVEL OF EVIDENCE: 3.

Infiltrating spinal angiolipoma.

Infiltrating angiolipomas are rarely encountered in the spine. We present a case involving a 71-year-old man with a dorsal epidural angiolipoma at the T5-T7 level. The tumor involved the T5-T6 vertebral bodies and left pedicle. The patient presented with acute paraparesis and MRI showed a homogeneously hyphointense lesion on T1-weighted images. The epidural component of the tumor was removed via laminectomy to achieve adequate cord decompression. The patient was symptom-free at a 2-year follow-up. This report emphasizes the unusual clinical presentation and MRI features of an infiltrating spinal angiolipoma and discusses therapeutic management options.

MicroED structure of the NaK ion channel reveals a Na+ partition process into the selectivity filter.

Sodium (Na+) is a ubiquitous and important inorganic salt mediating many critical biological processes such as neuronal excitation, signaling, and facilitation of various transporters. The hydration states of Na+ are proposed to play critical roles in determining the conductance and the selectivity of Na+ channels, yet they are rarely captured by conventional structural biology means. Here we use the emerging cryo-electron microscopy (cryoEM) method micro-electron diffraction (MicroED) to study the structure of a prototypical tetrameric Na+-conducting channel, NaK, to 2.5 Å resolution from nano-crystals. Two new conformations at the external site of NaK are identified, allowing us to visualize a partially hydrated Na+ ion at the entrance of the channel pore. A process of dilation coupled with Na+ movement is identified leading to valuable insights into the mechanism of ion conduction and gating. This study lays the ground work for future studies using MicroED in membrane protein biophysics.

Ion Binding to Transport Proteins using Isothermal Titration Calorimetry.

Isothermal titration calorimetry (ITC) is an emerging, label-free technology used to measure ligand binding to membrane proteins. This technology utilizes a titration calorimeter to measure the heat exchange upon ligands binding to proteins, the magnitude of which is based on the overall enthalpy of the reaction. In this protocol, the steps we and others use to measure ion binding to ion transport proteins are described.