Burden of neck pain in general population of China, 1990-2019: An analysis for the Global Burden of Disease Study 2019.

Background: Neck pain has become very common in China and has greatly affected individuals, families, and society in general. In this study, we aimed to report on the rates and trends of the prevalence, incidence, and years lived with disability (YLDs) caused by neck pain in the general population of China from 1990 to 2019. Methods: We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019) study to estimate the number and age standardised rates per 100 000 population of neck pain point prevalence, annual incidence, and YLDs in 33 provinces/municipalities/autonomous regions of China, stratified by age, sex, and sociodemographic index (SDI) from 1990 to 2019. We then compared these estimates with other G20 countries. Results: There were 6.80 × 107 patients with neck pain in 2019, presenting an increase from 3.79 × 107 in 1990. Likewise, the national age-standardised point prevalence increased slightly from 3.53% in 1990 to 3.57% in 2019. The YLDs increased by 78.08%, from 3814 × 103 in 1990 to 6792 × 103 in 2019. The age-standardised YLDs rate increased 1.50% from 352.84 in 1990 to 358.10 in 2019. The point prevalence of neck pain in 2019 was higher in females compared with males. These estimates were all above the global average level and increased more rapidly among G20 countries from 1990 to 2019. We generally observed a positive association between age-standardised YLD rates for neck pain and SDI, suggesting the burden is higher at higher sociodemographic indices. Conclusions: Neck pain is a serious public health problem in the general population in China, especially in its central and western regions, with an overall increasing trend in the last three decades. This is possibly related to changes of people's lifestyles and work patterns due to improvements in societal well-being and technology. Raising awareness of risk factors for neck pain in the general population and establishing effective preventive and treatment strategies could help reduce the future burden of neck disorders.

Incidence, prevalence, and causes of spinal injuries in China, 1990-2019: Findings from the Global Burden of Disease Study 2019.

BACKGROUND: Spinal injuries are an urgent public health priority; nevertheless, no China-wide studies of these injuries exist. This study measured the incidence, prevalence, causes, regional distribution, and annual trends of spinal injuries in China from 1990 to 2019. METHODS: We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 to estimate the incidence and prevalence of spinal injuries in China. The data of 33 provincial-level administrative regions (excluding Taiwan, China) provided by the National Center for Chronic and Noncommunicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention (CDC) were use to systematically analyze the provincial etiology, geographical distribution, and annual trends of spinal injuries. The Bayesian meta-regression tool DisMod-MR 2.1 was used to ensure the consistency among incidence, prevalence, and mortality rates in each case. RESULTS: From 1990 to 2019, the number of living patients with spinal injuries in China increased by 138.32%, from 2.14 million to 5.10 million, while the corresponding age-standardized prevalence increased from 0.20% (95% uncertainty interval [UI]: 0.18-0.21%) to 0.27% (95% UI: 0.26-0.29%). The incidence of spinal injuries in China increased by 89.91% (95% UI: 72.39-107.66%), and the prevalence increased by 98.20% (95% UI: 89.56-106.82%), both the most significant increases among the G20 countries; 71.00% of the increase could be explained by age-specific prevalence. In 2019, the incidence was 16.47 (95% UI: 12.08-22.00, per 100,000 population), and the prevalence was 358.30 (95% UI: 333.96-386.62, per 100,000 population). Based on the data of 33 provincial-level administrative regions provided by CDC, age-standardized incidence and prevalence were both highest in developed provinces in Eastern China. The primary causes were falls and road injuries; however, the prevalence and specific causes differed across provinces. CONCLUSIONS: In China, the overall disease burden of spinal injuries increased significantly during the past three decades but varied considerably according to geographical location. The primary causes were falls and road injuries; however, the prevalence and specific causes differed across provinces.

Adjacent segment degeneration after single- and double-level cervical total disc replacement: a cohort with an over 12-year follow-up.

PURPOSE: To characterize the change of adjacent segment degeneration (ASD) after cervical total disc replacement (CTDR) with more than 12-year follow-up, and identify the risk factors for ASD. METHOD: This process included 75 patients underwent CTDR from February 2004 to December 2012, with the follow-up of 151.9 ± 36.0 (m). The artificial disc included ProDisc-C, Prestige-LP and Mobi-C. ASD was followed up at 1 week, 6 months, 1 year, 2 years, 5 years, 10 years after CTDR and at the endpoint of June 2022. The radiographic measurements were cervical mobility, intervertebral disc height (IDH), cervical lordosis and balance status. The complications were implant migration, subsidence and heterotopic ossification (HO). RESULTS: Cervical mobility in adjacent segments, IDH and lordosis showed no statistical differences between ASD and NASD group. Balance status, subsidence and migration showed no relationship with ASD. Postoperative ASD increased at 6 m and especially between 6 m to 2y. There was no difference between the incidence of upper ASD and lower ASD all the time and few ASD-related reoperation. The majority of adjacent segments were C4/5 (33.6%) and C6/7 (34.2%), and ASD of C5/6 had the highest incidence (61.5%). Cox regression showed ASD was not related to the types of prosthesis or operated numbers. Generalized estimating equations (GEE) analysis showed severe HO had a higher (2.68 times) probability to suffer from ASD. CONCLUSIONS: After over 12-year follow-up of CTDR, the occurrence of ASD and HO had temporal synchronization. ASD was not merely a natural progression but with the pathological process such as HO.

Correlation between Degenerative Thoracolumbar Kyphosis and Lumbar Posterior Muscle.

The relationship between spinal alignment, particularly degenerative thoracolumbar kyphosis (DTLK) combined with lumbar spine stenosis (LSS), and paraspinal muscle content remains underexplored. This study aimed to elucidate the characteristics of paraspinal muscle distribution in DTLK patients and its association with lumbar lordosis (LL) and body mass index (BMI). METHODS: A case-control study was conducted comparing 126 patients with DTLK and LSS against 87 control patients. The lumbar crossing indentation value (LCIV) was introduced as a novel measurement for paraspinal muscle content, and its relationship with thoracolumbar kyphosis (TLK), BMI, and LL was assessed. RESULTS: LCIV in DTLK patients was found to be lower than in the control group, with a progressive increase from the upper to lower lumbar spine. In the control group, paraspinal muscle content was observed to increase with age and BMI, and LCIV was higher in males. However, the DTLK group showed no gender difference. LCIV in the DTLK group was more pronounced in patients with increased LL. The degree of TLK was not influenced by BMI but was associated with the content of the paravertebral muscle. CONCLUSIONS: Paraspinal muscle content, as measured by LCIV, is significantly associated with DTLK and LSS. The study emphasizes the importance of considering paraspinal muscle health in DTLK patients and offers valuable insights for diagnosis and therapeutic interventions.

Perioperative risk factors related to complications of lumbar spine fusion surgery in elderly patients.

PURPOSE: To analyze the perioperative risk factors related to lumbar spine fusion surgery in elderly patients. METHODS: 202 elderly patients (age range 77-92 years old) who have underwent lumbar spinal fusion surgeries between January 2019 and June 2021 were retrospectively investigated. Information of age, sex, comorbidity, fixation segments, operation time, surgical blood loss and perioperative complications during hospitalization were collected. Risk factors for complications were analyzed. Student's t-test, chi-square test, Mann-Whitney U­test and multivariate generalized linear models were used. RESULTS: In this study, 31 patients presented complications (15.3%) in these elderly patients with an average age of 79.1 years, including 1 patient with intraoperative complication and 30 patients with postoperative complications; and 2 out of 31 patients (1%) died. The elderly patients were divided into group A (24 patients) with major postoperative complications and group B (178 patients) without major postoperative complications. Major postoperative complications were significantly associated with age (univariate analysis, t = 3.92, P < 0.001; multivariate analysis, OR = 1.323, 95%CI 1.126-1.554, P = 0.001), but not significantly associated with other factors tested (sex, comorbidity, fixation segments, operation time, surgical blood loss). Then 173 patients (range 77-81 years) were selected and the rate of major postoperative complications of each age from 78 to 81 years was compared with that of 77 years patients, respectively. We found that the ratios of complications at 80 years (OR = 10.000, P = 0.019) and 81 years (OR = 10.000, P = 0.009) were higher than the ratio at 77 years. CONCLUSIONS: Although with great progress of medical technology, increasing age was still the independent risk factor for major postoperative complications in elderly patients undergoing lumbar spinal fusion surgery. As for the incidence of major postoperative complications, 80 and 81 years old patients was 10 folds higher than that of 77 years old patients, reminding us to pay more attention to 80 years old and even older patients.

Study on the crystallization behavior and conformation adjustment scale of poly(lactic acid) in the terahertz frequency range.

The observed properties of crystalline polymers are determined by their internal structure, which in turn is the result of their different crystallization behaviors. Here, we investigate the crystallization behavior of poly(lactic acid) (PLA) by terahertz time-domain spectroscopy (THz-TDS) at varied temperatures. We find that the changes in the chain packing and conformation of PLA are characterized by THz spectroscopy. Combining X-ray diffraction (XRD) and infrared spectroscopy (IR), we attributed the blue-shift of the THz peak to the tightness of the chain packing, while its absorption enhancement is caused by the conformation transition. The effects of chain packing and chain conformation on the characteristic peak are phased. Furthermore, absorption discontinuities of the characteristic peaks of PLA crystallized at different temperatures are observed, which originated from differences in the degree of conformational transition caused by different thermal energies. We find that the crystallization temperature at which the absorption mutation of PLA occurs corresponds to the temperature at which the motion of the segment and molecular chain is excited, respectively. At these two temperatures, PLA exhibits different scales of conformational transitions leading to stronger absorption and larger absorption changes at higher crystallization temperatures. The results demonstrate that the driving force of PLA crystallization is indeed from changes in chain packing and chain conformation, and the molecular motion scale can also be characterized by THz spectroscopy.

Terahertz spectroscopy for quantitatively elucidating the crystal transformation of chiral histidine enantiomers to racemic compounds.

d-Histidine (d-His), l-Histidine (l-His), and their racemic compound dl-Histidine (dl-His) have different stereo chirality, making them intrinsic diverse functionalities to the living system. Identifying the configuration and crystal structures of enantiomers and the racemic compound is always the foremost requirement in processing protein foods. Although these features can be analyzed by spectroscopic technologies individually, it remains challenging to incorporate these complex methods into a facile analytical strategy. Herein, we propose a terahertz spectroscopy with solid-state density functional theory to both distinguish the configurational difference and quantify the crystal transformation from l-His and d-His to dl-His. By comparison with X-ray diffraction analysis, the validity of the crystal transformation evaluation based on terahertz spectroscopy is verified. A normalized fitting line regarding the terahertz absorption frequency and intensity is calculated to quantitatively elucidate the crystal transformation from enantiomers to dl-His. Our findings provide a new analytical approach to the research on food chemistry.

Thoracolumbar/Lumbar Degenerative Kyphosis-The Importance of Thoracolumbar Junction in Sagittal Alignment and Balance.

PURPOSE: To conduct a more comprehensive study of sagittal alignment in patients with thoracolumbar/lumbar (TL/L) degenerative kyphosis. METHODS: A total of 133 consecutive patients from September 2016 to March 2019 with degenerative spinal kyphosis were enrolled. These patients were divided into different types according to sagittal alignment, including thoracolumbar junctional kyphosis (TLJK). Then, we divided the patients with TLJK into two groups: the Sagittal Balance group (C7-SVA < 50 mm) and the Sagittal Imbalance group (C7-SVA ≥ 50 mm). The sagittal parameters of each type or group were compared and correlation analysis was conducted. RESULTS: Thoracolumbar/lumbar degenerative kyphosis consists of four types: Type I, lumbar kyphosis; Type II, degenerative flat back; Type III, thoracolumbar junctional kyphosis; and Type IV, global kyphosis. According to different sagittal alignments, Type III can further be divided into three subtypes: IIIA, with smooth kyphosis of thoracic and upper lumbar; IIIB, like a clasp knife, with a flat thoracic and lumbar angle; and IIIC, with bigger thoracic kyphosis and lumbar lordosis. The thoracolumbar kyphosis angle (°) of the three subtypes were -23.61 ± 5.37, -25.40 ± 7.71, and -40.01 ± 8.40, respectively. Lumbar lordosis was correlated with thoracic kyphosis (IIIA, r = -0.600, p = 0.005; IIIB, r = -0.312, p = 0.046; IIIC, r = -0.657, p = 0.015), and correlated with sacral slope (IIIA, r = 0.537, p = 0.015; IIIB, r = 0.654, p = 0.000; IIIC, r = 0.578, p = 0.039). All spinopelvic parameters were compared between the Sagittal Balance group and the Sagittal Imbalance group, and only the thoracolumbar kyphosis angle showed statistical difference (t = -2.247, p = 0.028). CONCLUSIONS: The common characteristics of thoracolumbar junctional kyphosis were found to be a bigger thoracolumbar junctional angle and vertex of kyphosis located in the thoracolumbar junction (T10-L2). Despite TLJK, a change in the thoracic angle was still important to maintain sagittal balance. The thoracolumbar junction plays an important role in sagittal alignment and balance.

Sagittal Parameters of Spine-Pelvis-Hip Joints in Patients with Lumbar Spinal Stenosis.

OBJECTIVE: To explore sagittal compensation characteristics, including extra spinal-pelvic parameters and distal hip parameters, for analysis in middle-aged to the older patients with lumbar spinal stenosis (LSS) without spinal deformity and clarify the fitting relationship between the main sagittal parameters. METHODS: This retrospective single-center study included 205 patients with LSS in our department from January 2016 to December 2018, including 153 women (74.6%), with an average age of 67.6 ± 7.1 years. Sagittal parameters were obtained on the whole spinal lateral radiograph. Spinal parameters include thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), and lumbar lordosis (LL). Pelvic parameters include pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS). Hip parameters include pelvic rotation (PR) and hip inclination angle (HIA). Spine-pelvic parameter is spino-sacral angle (SSA). Sagittal balance parameter is sagittal vertical axis (SVA). PI-LL, PT, SVA, HIA, and TLK were regarded as primary results, and the others were secondary outcomes. The independent sample t-test was used to compare gender. Pearson correlation analysis was used to evaluate the correlation between primary results and secondary results. We take PI-LL, PT, SVA, and TLK as dependent variables and include relevant factors for analysis. RESULTS: In the case of gender, PI, PI-LL, and PT were found smaller in men than women, but TK is greater in men than women (27.3° ± 6.1° vs 23.3° ± 7.7°, p = 0.033). PI-LL was positively correlated with PT (r = 0.608, p < 0.001) and negatively correlated with HIA (r = -0.193, p = 0.010); PT was negatively correlated with HIA (r = -0.289, p < 0.01). As to the relationship between primary and secondary results, HIA was positively correlated with SS and PR (p < 0.01). SVA was positively correlated with SSA (r = 0.341, p = 0.010). The positive influencing factors and risk factors of SVA were SSA, and PI-LL played a negative regulatory role through proximal TK, the distal PT plays a positive regulatory role. The regulation of PI-LL was compensated through both TK and PT, with a fitting relationship of PI-LL = 0.5 × PT - 0.2 × TK. CONCLUSION: There was a close interaction among spine-pelvic-hip sagittal parameters. We found the matching of PI-LL in the domestic middle-aged and elderly LSS population is regulated by thoracic spine and pelvis.

Study of Crystallinity and Conformation of Poly(lactic acid) by Terahertz Spectroscopy.

During crystallization, conformational changes are often accompanied by the formation of interactions. Terahertz (THz) spectroscopy exhibits strong responses to the crystalline poly(lactic acid) (PLA). Therefore, we estimate the relative crystallinity and investigate the effect of conformational transition on the vibration of PLA by THz spectroscopy. By comparing with the results of X-ray diffraction (XRD) and differential scanning calorimetry (DSC), the validity of THz spectroscopy to calculate crystallinity is verified. Furthermore, the peak intensity of PLA at 2.01 THz increases with crystallinity. Combined with Fourier transform infrared spectroscopy (FTIR), the vibrational intensity of PLA at 2.01 THz is highly correlated with the contribution of gt conformation, showing a linear relationship. In addition, the vibrational peak of PLA also reflects the interchain interactions. We believe that the increase in peak intensity with increasing crystallinity originates from the effect of the dipole-dipole interactions between the carbonyl groups. Our study demonstrates the ability of THz spectroscopy to estimate the crystallinity of PLA, and the peak at 2.01 THz shows conformational and interaction sensitivities.

Terahertz Spectroscopy Study of the Stereoisomers of Threonine.

The terahertz (THz) band contains a wealth of information about vibration and rotational energy levels, most of the vibration modes between amino acid molecules are in the THz band, so it reflects many unique absorption characteristics in the THz band. The use of terahertz time-domain spectroscopy can not only effectively identify different kinds of amino acids but also distinguish various isomers of the same amino acid due to the varied vibration modes. The absorption spectra of four stereoisomers of threonine were investigated by terahertz time-domain spectroscopy (THz-TDS) and Fourier transform infrared spectroscopy. The results show that the isomers show similarity in the infrared band, while manifest evidently the similarity between enantiomers L-threonine and D-threonine, and between L-allo-threonine and D-allo-threonine, and the difference between diastereoisomer L-threonine/D-threonine and L-allo-threonine/D-allo-threonine in the terahertz band. In order to fully understand the origin of the terahertz absorption characteristics of isomer molecules, simulation calculations were carried out in combination with density functional theory to connect the vibrational modes and molecular structures, Furthermore, the unit cell configurations of L-thr and L-allo-thr and the differences between various low-frequency vibrational modes are analyzed from the perspective of hydrogen bond configuration. By further extracting terahertz optical parameters such as refractive index and imaginary part of the dielectric constant of threonine isomers, the results show that the refractive index spectrum and dielectric loss spectrum can clearly show the response characteristics of the orientation polarization of dipole inside threonine isomers in terahertz band.

Terahertz spectroscopy for interpreting the formation and hierarchical structures of silk fibroin oligopeptides.

Determining the configuration and conformation of peptides is crucial for interpreting their structure-property relationships. In this work, we present nondestructive terahertz time-domain spectroscopy combined with density functional theory (DFT) and potential energy distribution (PED) analysis to identify the hierarchical structures of oligopeptides. The characteristic THz spectra of silk fibroin oligopeptides have been measured. Supported by DFT and PED analysis, the intrinsic differences among the dipeptides were identified by the collective vibrational modes of "R" groups and terminal groups linked by molecular chains of amido bonds or benzene rings. For tetrapeptides and hexapeptides, a few weak resonances and intensity differences were distinguished by the vibration mode of the molecular collective network formed by the interaction of amide planes and intramolecular hydrogen bond interactions. According to the THz absorption analyses of amide planes and intramolecular interactions within the molecular chains of silk fibroin oligopeptide isomer pairs, the formation and hierarchical structures were successfully interpreted using THz spectroscopy. This investigation develops a better understanding of the peptide formation mechanism, which further provides guidance in interpreting the formation of silk.

Terahertz spectroscopy of temperature-induced transformation between glutamic acid, pyroglutamic acid and racemic pyroglutamic acid.

Under heating conditions, L-Glutamic acid (L-Glu) can be dehydrated to form L-pyroglutamic acid (L-PGA), and L-PGA can racemize to form DL-PGA. Here, we characterized this transformation at different temperatures and times by terahertz time domain spectroscopy (THz-TDS). By Powder X-ray diffraction (PXRD), the validity of THz spectroscopy is verified. The results prove that the reaction rate of dehydration and racemization is significantly affected by temperature. The THz spectra divided the reactions into three stages. At 150-155 °C, the reaction changes drastically. Furthermore, we found that the absorption intensity at 0.97 and 1.55 THz has a good dependence on the reaction temperature and time, showing a non-linear relationship (R2 > 0.98). Our findings suggest that the chemical transformation and reaction rate can be sensitively probed by terahertz spectroscopy, which provides a potential method for the quantitative analysis of reaction products.

Evaluation of formation and proportion of secondary structure in γ-polyglutamic acid by terahertz time-domain spectroscopy.

The study of secondary structure is essential for understanding peptides and proteins. Here, we measured the terahertz (THz) spectra of γ-polyglutamic acid (γ-PGA) dominated by α-helix and random coil (RC) respectively. The α-helix has two absorption peaks in the THz region, but no absorption peak is observed in the RC conformation. We believe this is because the hydrogen bonding effect leads to a higher orientation in the helix-dominated γ-PGA. At lower pH, the absorption intensity of γ-PGA increases with the induction time. Similar changes were obtained in the Fourier infrared spectroscopy (FTIR). Through the correlation analysis of THz and IR spectroscopy, it is found that the characteristic peak at 1.2 THz can be used as a sensitive indicator of the intermediate conformation of the α-helical structure. In addition, the transformation of α-helix-RC conformation is related to the peak intensity at 1.99 THz (R2 = 0.991), which preliminarily indicates that terahertz time-domain spectroscopy (THz-TDS) has the potential to become a new effective method for characterizing and evaluating secondary structure.

Examination of proline, hydroxyproline and pyroglutamic acid with different polar groups by terahertz spectroscopy.

Hydroxyproline (HYP) and pyroglutamic acid (PGA), as amino acid derivatives, are highly similar in structure to proline (Pro). However, their low-frequency vibrations show significant differences in the range of 0.25-2.6 THz. Therefore, this study investigated the reasons for the differences combined with terahertz time domain spectroscopy (THz-TDS) and density functional theory (DFT). The results show that HYP and PGA have stronger absorption of terahertz waves due to the existence of polar substituents. Furthermore, the absorption peaks of HYP and PGA are significant red shifted and blue shifted, respectively. We believe that this is caused by the change in the strength of intermolecular hydrogen bonds. Our findings demonstrate that dipole and hydrogen bond effects play a significant role in low-frequency vibrations.

Posterior instrumented fusion on lumbar stenosis syndrome can bring benefit to proximal degenerative kyphosis: A CONSORT-compliant article.

ABSTRACT: The effect on degenerative thoracolumbar kyphosis (DTLK) after short-segment instrument for lumbar spinal stenosis syndrome (LSS) remains controversial. Based on the biomechanics and compensatory of the global spino-pelvic alignment, it was assumed that the interference on the lumbar spine, instead of the thoracolumbar segment, could still make a difference on the proximal spine.To explore whether DTLK could improve with only surgery for LSS and identify influencing factors on postoperative TLK.The study was performed from January 2016 to December 2018. Sixty-nine participants (25 male) diagnosed LSS with DTLK were enrolled and surgery was only for LSS. Radiological parameters included TLK, lumbar lordosis, pelvic incidence, pelvic tilt, sacral slope, and osteoporosis. Clinical outcomes were visual analogue scale and Oswestry disability index. According to lower instrumented vertebrae (LIV) on L5 or S1, inter-group comparisons were performed between LIV on L5 (L5 group) and S1 (S1 group).Demographics were well-matched between L5 and S1 group with a mean follow-up of 24.3 ±â€Š12.1 (m). TLK improved with a mean of 16.2 ±â€Š7.6 (°) (P < .001). There was no significance on radiological and clinical parameters between L5 and S1 groups except for a larger pelvic tilt in S1 group (P = .046). Visual analogue scale (P = .787) and Oswestry disability index (P = .530) were both indifferent between normal TLK and DTLK at last (P > .05). Postoperative TLK was affected by osteoporosis and sacral slope, the latter was dominated by pelvic incidence and pelvic rotation. Osteoporosis was the risk factor for TLK correction (P = .001, odd risk = 9.58).DTLK decreased if instrument only performed for LSS, where TLK and clinical outcomes are comparably affected whether L5 or S1 is selected as LIV. This study supplements the compensatory mechanism of spino-pelvic alignment, especially for cases with severe osteoporosis.

Abdominal changes in patients with degenerative spinal deformity: A comparative study.

ABSTRACT: The incidence of degenerative spinal deformity (DSD) is increasing with the age while the effect of DSD on the abdominal cavity parameters is unclear.To identify the characteristics of abdominal change in DSD and to explore the correlation between the abdominal cavity volume (ACV) and various types of DSD.The retrospective study included 95 patients with DSD and 100 subjects without deformity as control group. The Cobb angle, thoracic kyphosis angle, thoracolumbar kyphosis (TLK) angle, and lumbar kyphosis angle were obtained through full-length X-ray. The ACV was calculated by measuring the longitudinal, transversal, and coronal diameters of the abdominal cavity on magnetic resonance imaging (MRI). The rotation of the diaphragm (DR) were measured in the sagittal plane. DSD ones were divided into degenerative lumbar scoliosis (DLS group), degenerative kyphosis (DK group), and degenerative lumbar scoliokyphosis (DKS group).Compared to control group, ACV of the DLS and DKS group was smaller. The distance between the xiphoid process and spine in DLS group was shorter and DR in DK group and DKS group was smaller. The inter-group analysis showed ACV and the shortest distance between xiphoid process and spine in DLS and DKS group were significantly lower than those in DK group. The degree of DR in DK group and DKS group was higher than that in the DLS group. Multiple linear regression analysis showed Cobb angle and weight were influencing factors of ACV with ACV = 0.67 × weight - 0.19 × Cobb angle + 2231.8. The DR was affected by TLK with DR = 25.82 - 0.42 × TLK.DLS can cause the decrease of ACV. DK will not cause changes of ACV but is related to the degree of kyphosis. DKS will impact both ACV and DR.

Modified Hidden Blood Loss Based on Drainage in Posterior Surgery on Lumbar Stenosis Syndrome with Rheumatoid Arthritis.

OBJECTIVE: Publications on hidden blood loss (HBL) after posterior lumbar interbody fusion (PLIF) for lumbar spine stenosis syndrome (LSS) have been reported, but the modified HBL (mHBL) was different from HBL obtained by classical formula and there are few studies on lumbar spine hemorrhage with rheumatoid arthritis (RA). Therefore, the aim of our study is to respectively evaluate the importance of hidden blood loss (HBL) and modified HBL (mHBL) after posterior lumbar interbody fusion (PLIF) in patients diagnosed with LSS and RA, to explore the correlation between RA activity and HBL as well as mHBL. METHODS: A total of 61 patients (nine males and 52 females) diagnosed with LSS and RA who underwent PLIF were included. Data contained demographics, RA-related parameters such as duration of RA, Steinbrocker classification (used to evaluated RA activity), the disease-modifying anti-rheumatic drugs (DMARDs), osteoporosis and total knee arthroplasty; operation and hemorrhage parameters. Then HBL and mHBL were calculated by Gross formula and modified formula, respectively. Subgroup analysis on HBL and mHBL was performed based on gender, age (≤60 years and ˃60 years), different number of surgical segments (single segment, double segment, and ≥3 segments), and taking DMARDs or not. ANOVA analysis was performed on HBL and mHBL in different surgery segment number and Steinbrocker classification of RA. Independent sample t-test was used in comparison of gender and age, as well as in comparison between HBL and mHBL based on whether the patient took DMARDs or not. Furthermore, paired t-test was used to compare the volume between HBL and mHBL. RESULTS: The mean age and duration of RA was 65.2 ± 9.3 years and 14.3 ± 10.7 years, respectively. There were 13 grade I cases, 34 grade II cases, and 14 grade III cases as assessed by Steinbrocker classification and the most common anti-RA drugs were DMARDs (57.4%). The mean intraoperative bleeding, drainage, and blood loss in drainage (DBL) was 453.3 ± 377.8 mL, 489.1 ± 253.8 mL, and 304.6 ± 156.3 mL, respectively. There was no difference on HBL and mHBL in gender. HBL and mHBL was larger in patients over 60 years (P = 0.040 and P = 0.023). There were differences in intraoperative blood loss, drainage, and DBL based on different number of segments but not in HBL and mHBL, or on Steinbrocker classification. DBL was lower in DMARDs group than non-drugged group (P = 0.03), while HBL and mHBL were both of no significance. The comparison of HBL and mHBL showed statistical difference (P < 0.001), suggesting that mHBL volume is larger than HBL. CONCLUSIONS: Patients diagnosed as LSS with RA have amounts of HBL or mHBL after PLIF. HBL or mHBL is not associated with RA activity, which may not increase in RA patients compared with common ones. Taking DMARDs may reduce postoperative DBL. The fact that mHBL is larger than HBL provides an all-round basis for measuring factual HBL.

The compensatory mechanisms for global sagittal balance in degenerative spinal kyphosis patients: a radiological analysis of muscle-skeletal associations.

BACKGROUND: The position of the head relative to the spine can be used to evaluate the true global balance in patients with degenerative spinal kyphosis (DSK). However, it is still not clear how the position of the head is related to the spinal-pelvic parameters and lumbar muscles, which are most commonly considered. METHODS: Sixty-seven patients with DSK admitted in the hospital from January 2017 to January 2019 were retrospectively analyzed. All patients had whole spine X-ray and lumbar MRI. The head position parameters include: the angles of both lines joining the center of acoustic meati (CAM) to the center of the bi-coxofemoral axis (BA) (CAM-BA) and the most superior point of dentiform apophyse of C2 odontoid (OD) to BA (OD-BA) with the vertical line; the distance between the vertical line passing CAM and the posterior upper edge of the S1 (CAM-SVA). The spinal parameters include: C7 sagittal vertical axis (C7-SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), and lumbar lordosis (LL). The pelvic parameters include: pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). The relative cross-sectional area (RCSA) of bilateral multifidus, erector spinae and psoas muscle at L3/4 and L4/5 segments were measured. The correlations between head position parameters and the spinal-pelvic parameters and RCSA of lumbar muscles were analyzed, respectively. RESULTS: Significant positive correlations were found between each two of CAM-SVA, C7-SVA, CAM-BA and OD-BA (p < 0.001). SS was found to be significantly positively correlated with CAM-BA (r = 0.377, p = 0.034) and OD-BA (r = 0.402, p = 0.023). CAM-BA was found to be significantly negatively correlated with TK (r = - 0.367, p = 0.039). Significant positive correlations were found between RCSA of multifidus at L3/4 level and CAM-SVA (r = 0.413, p = 0.021), CAM-BA (r = 0.412, p = 0.019) and OD-BA (r = 0.366, p = 0.04). CONCLUSIONS: Our study showed that the head position relative to the spine were significantly correlated to some spinal-pelvic parameters, and the lower lumbar multifidus muscle. The compensatory mechanisms of the global sagittal balance status should also involve the head position area.