Ecological dynamics of terrestrial and freshwater ecosystems across three mid-Phanerozoic mass extinctions from northwest China.

The Earth has been beset by many crises during its history, and yet comparing the ecological impacts of these mass extinctions has been difficult. Key questions concern the kinds of species that go extinct and survive, how communities rebuild in the post-extinction recovery phase, and especially how the scaling of events affects these processes. Here, we explore ecological impacts of terrestrial and freshwater ecosystems in three mass extinctions through the mid-Phanerozoic, a span of 121 million years (295-174 Ma). This critical duration encompasses the largest mass extinction of all time, the Permian-Triassic (P-Tr) and is flanked by two smaller crises, the Guadalupian-Lopingian (G-L) and Triassic-Jurassic (T-J) mass extinctions. Palaeocommunity dynamics modelling of 14 terrestrial and freshwater communities through a long sedimentary succession from the lower Permian to the lower Jurassic in northern Xinjiang, northwest China, shows that the P-Tr mass extinction differed from the other two in two ways: (i) ecological recovery from this extinction was prolonged and the three post-extinction communities in the Early Triassic showed low stability and highly variable and unpredictable responses to perturbation primarily following the huge losses of species, guilds and trophic space; and (ii) the G-L and T-J extinctions were each preceded by low-stability communities, but post-extinction recovery was rapid. Our results confirm the uniqueness of the P-Tr mass extinction and shed light on the trophic structure and ecological dynamics of terrestrial and freshwater ecosystems across the three mid-Phanerozoic extinctions, and how complex communities respond to environmental stress and how communities recovered after the crisis. Comparisons with the coeval communities from the Karoo Basin, South Africa show that geographically and compositionally different communities of terrestrial ecosystems were affected in much the same way by the P-Tr extinction.

How does the sagittal spinal balance of the scoliotic population deviate from the asymptomatic population?

BACKGROUND: Previously, the sagittal spinal balance in both asymptomatic and scoliotic Caucasian people has been characterized and compared. Very recently, the sagittal spino-pelvic parameters among asymptomatic Chinese adults have been studied, and the results were compared with Caucasian adults, indicating that a difference did exist. Unfortunately, the distribution of sagittal standing posture patterns among the Chinese population has not been characterized in either asymptomatic or scoliotic groups. METHODS: We conducted a radiographic comparison study to define the deviation of sagittal balance in scoliotic patients from that of an asymptomatic population. A total of 126 asymptomatic and 117 idiopathic scoliotic (IS) young adults were recruited. Radiographic data from each subject were reviewed, and sagittal spinopelvic parameters were measured. The Roussouly type was then determined, as well as the relative position of the C7 plumbline with respect to the sacrum and hip axis. Comparison analyses were undertaken between the two different groups. RESULTS: The IS group had a larger pelvic incidence, pelvic tilt and sacral slope, but a smaller spinal tilt than the asymptomatic group (P < 0.05), while other sagittal parameters were similar. The distribution of Roussouly types was similar between the asymptomatic and IS groups, of which 49.2% and 45.3% belonged to Roussouly Type 3, respectively. Asymptomatic males and females had a similar distribution, which was different between the two genders in the IS group (P < 0.05), with more females possessing a neutral sagittal standing posture. In addition, more IS subjects had forward displacement of the C7 plumbline than asymptomatic ones (P < 0.05), while there was no difference between the two genders in either group. CONCLUSIONS: Although sagittal pelvic parameters were greater in the IS population, their sagittal spinal balance was maintained and there was no sagittal standing posture pattern correlated with IS. The occurrence of anterior displacement of the C7 plumbline was more common in IS patients than asymptomatic adults, but did not appear to be correlated with gender in both populations.

New keratose sponges after the end-Permian extinction provide insights into biotic recoveries.

We challenge the prevailing view that the end-Permian extinction impeded the Triassic evolution of sponges. Here, we report a deep-water community dominated by abundant keratose sponges in the lowest Triassic strata from Southwest China. The sponge fossils occur as dark elliptical imprints in mudstone with distinct oscula on their tops. The structure of preserved fibers suggests closest affinity with the extant Dictyoceratida, an aspiculate demosponge. The exceptional preservation plays a crucial role in retaining their exquisite structures. Sedimentary, taphonomic, pyrite framboid, and trace elemental analyses indicate that the sponges proliferated in an oxygen-poor habitat, demonstrating the high tolerance of sponges to severe conditions. Sponge proliferation is a signal of environmental upheaval but they also stabilized the ecosystem, driving the first phase of biotic recovery after the end-Permian extinction.

Epidemiological survey of ossification of the ligamentum flavum in thoracic spine: CT imaging observation of 993 cases.

OBJECTIVE: To investigate the characteristics of epidemiological distribution of the ossification of the ligamentum flavum (OLF) in the thoracic spine including the incidence, segmental distribution, and shape. METHODS: Chest spiral computed tomography scans of 993 cases (male 506, female 487, mean age 60 years, range 5-102 years) who presented due to chest symptoms were analyzed with axial slices combined with sagittal slices. The conditions of OLF in the thoracic spine, including segments, thickness, location, and dural sac compression, were recorded. Prevalence was standardized according to the "Age Structure of Population in Beijing 2008". RESULTS: Among the population investigated, the standardized prevalence rate was 63.9 %. The standardized prevalence rate for males (68.5 %) was higher than that for females (59.0 %). The highest prevalence rate of OLF was in the 50-59 years age group (79.2 %); however, high density originated it can be found in individuals aged 10-19 years. The comparison of different thoracic segments showed that T10-11 (44.0 %) and T11-12 (41.6 %) had the highest prevalence rates. CONCLUSION: The prevalence of ossification of the ligamentum flavum was highest in the 50-59 years group, but also occurred in early years. OLF occurs more frequently in the lower than in the upper and middle thoracic regions and its prevalence increases with aging.

Bayesian analyses indicate bivalves did not drive the downfall of brachiopods following the Permian-Triassic mass extinction.

Certain times of major biotic replacement have often been interpreted as broadly competitive, mediated by innovation in the succeeding clades. A classic example was the switch from brachiopods to bivalves as major seabed organisms following the Permian-Triassic mass extinction (PTME), ~252 million years ago. This was attributed to competitive exclusion of brachiopods by the better adapted bivalves or simply to the fact that brachiopods had been hit especially hard by the PTME. The brachiopod-bivalve switch is emblematic of the global turnover of marine faunas from Palaeozoic-type to Modern-type triggered by the PTME. Here, using Bayesian analyses, we find that unexpectedly the two clades displayed similar large-scale trends of diversification before the Jurassic. Insight from a multivariate birth-death model shows that the extinction of major brachiopod clades during the PTME set the stage for the brachiopod-bivalve switch, with differential responses to high ocean temperatures post-extinction further facilitating their displacement by bivalves. Our study strengthens evidence that brachiopods and bivalves were not competitors over macroevolutionary time scales, with extinction events and environmental stresses shaping their divergent fates.

The stability and collapse of marine ecosystems during the Permian-Triassic mass extinction.

The history of Earth's biodiversity is punctuated episodically by mass extinctions. These are characterized by major declines of taxon richness, but the accompanying ecological collapse has rarely been evaluated quantitatively. The Permian-Triassic mass extinction (PTME; ∼252 mya), as the greatest known extinction, permanently altered marine ecosystems and paved the way for the transition from Paleozoic to Mesozoic evolutionary faunas. Thus, the PTME offers a window into the relationship between taxon richness and ecological dynamics of ecosystems during a severe extinction. However, the accompanying ecological collapse through the PTME has not been evaluated in detail. Here, using food-web models and a marine paleocommunity dataset spanning the PTME, we show that after the first extinction phase, community stability decreased only slightly despite the loss of more than half of taxonomic diversity, while community stability significantly decreased in the second phase. Thus, taxonomic and ecological changes were unequivocally decoupled, with species richness declining severely ∼61 ka earlier than the collapse of marine ecosystem stability, implying that in major catastrophes, a biodiversity crash may be the harbinger of a more devastating ecosystem collapse.

[The posterior surgical treatment of old tuberculous kyphosis].

OBJECTIVE: To observe the results of posterior osteotomy and correction in the surgical treatment of old tuberculous kyphosis. METHODS: From June 2004 to December 2008, 31 cases of old tuberculous kyphosis with posterior osteotomy and correction technique were treated. There were 12 cases of male and 19 cases of female. The average age was 33.4 years. Pedicle subtraction osteotomy or vertebral column resection were applied in surgery. The kyphosis angle, lumbar lordosis angle and sagittal balance condition of the spine were measured before and after surgery, as well as follow-up. The Frankel grading system for neurological function of lower extremities, the Oswestry disability index (ODI) for life quality, and patient satisfactory index (PSI) for satisfaction of surgery were applied before surgery and at follow-up. RESULTS: The average kyphosis angle was 94° ± 27°, the average lumbar lordosis angle was 71° ± 20°, and the average sagittal C(7) plumb line was (-15 ± 44) mm away from the balance region before surgery. The average kyphosis angle decreased to 26° ± 11° in one week after surgery, with an improvement rate of 71.4%. The average follow-up time was 22.5 months. The average kyphosis angle was 28° ± 12° at the final follow-up, with an improvement rate of 70.0%. The average lumbar lordosis angle was 46° ± 11°, with an improvement rate of 35.1%. The postoperative kyphosis angle and lumbar lordosis angle were significantly different with that of pre-operation (for kyphosis angle: t = 16.3, P < 0.05; for lumbar lordosis angle: t = 8.1, P < 0.05). The average sagittal C(7) plumb line was (-4 ± 22) mm away from the balance region at the final follow-up, with an improvement rate of 73.4%. The Frankel grading were E in 13 cases, D in 13 cases, and C in 5 cases before surgery, and were E in 20 cases, D in 8 cases, and C in 3 cases at the final follow-up. The average ODI was 13 ± 12 before surgery, and was 7 ± 8 at the final follow-up, with an improvement rate of 45.2%. The PSI results showed a satisfied rate of 90.3%. CONCLUSION: Good results can be achieved by applying proper posterior osteotomy and correction technique according to the severity of old tuberculous kyphosis.

[Longterm outcome after the decompressive surgery for thoracic myelopathy due to the ossification of the ligamentum flavum].

OBJECTIVES: To investigate the long-term surgical outcome of thoracic myelopathy caused by the ossification of the ligamentum flavum (OLF) and evaluate the related risk factors. METHODS: Forty-four patients who underwent decompressive laminectomy with thoracic OLF between January 1990 and December 2005 and got more than 5 years follow-up were retrospectively reviewed. Among these 44 cases, there were 29 male and 15 female whose ages at operation were 52 years averagely (27-68 years). The 2-year follow-up results and long-term outcomes were classified according to the modified Epstein's standard, and then the rates of excellent or good (REG) were calculated. The correlation between the long-term REG and the patients' ages, durations of symptoms, decompressed levels, and dural leak were analyzed. RESULTS: The mean follow-up period of these 44 cases was 8.5 years (5-19 years). The REG at 2 years after laminectomy was 77.3% (34/44), while the long-term REG was 65.9% (29/44). There was one case who had suffered from an acute spinal cord injury got a poor post-operative outcome. The other 43 cases had chronic durations, including 22 cases whose pre-operative durations of symptoms were less than 12 months and 21 cases whose durations were equal to or more than 12 months. And the long-term REG of these two groups were 77.3% (17/22) and 57.1% (12/21) respectively (P>0.05). The REG of those cases whose decompression levels were limited in T1-T9 was 78.9% (15/19), while that of those cases whose laminectomy was relevant to thoracolumbar segment (T10-L2) was 58.3% (14/24) (P>0.05). There were 7 cases who had excellent or good short-term results and poor long-term outcomes. The reasons of these changes included coexistence of lumbar spinal stenosis in three cases and the growth of the OLF at the adjacent levels in four cases. CONCLUSIONS: Although the short-term results of the decompressive surgery for thoracic OLF is good, the regular long-term follow-up is necessary because the symptoms may reoccur or deteriorate secondary to lumbar spinal stenosis or the growth of OLF at the adjacent levels near former decompressive levels; the duration of symptoms which is more than one year and the decompression levels that is involved to T10-L2 segments are possibly related to the poor long-term outcomes.

Treatment of Thoracic Ossification of Posterior Longitudinal Ligament with One-Stage 360 Degree Circumferential Decompression Assisted by Piezosurgery.

OBJECTIVES: To evaluate the safety and clinical efficacy of One-Stage 360 degree circular decompression for thoracic ossification of the posterior longitudinal ligament (TOPLL) assisted by piezosurgery. MATERIALS AND METHODS: The present study enrolled 36 patients with TOPLL between August 2016 and February 2019. The average intraoperative bleeding volume of all 36 patients in this study is 1058.61 ±737.66 ml. RESULTS: All patients did not experience any intraoperative complications such as spinal cord and nerve injuries, and 22 other complications related to decompression of OPLL cited in other literature; all of which were relieved after treatment. The resection time of single laminectomy was 3.43 ±0.49 min, and circular decompression was 42.06 ±14.22 min. At the last follow-up, the modified Japanese Orthopaedic Association (mJOA) score was 8.89 ±1.56, the recovery rate of spinal cord function was 64.2 ±21.2%, and the number of cases of spinal cord function deterioration was 0 (0%). The mJOA score of the last follow-up was negatively correlated with the time of circular decompression (r = 0.368, p ＜ 0.01) and age (r = 0.412, p = 0.026). The recovery rate of the spinal cord function was negatively correlated with the operation time of circular decompression (r = -0.325, p = 0.041) and the amount of intraoperative blood loss (r = -0.555, p = 0.028). CONCLUSIONS: The use of piezosurgery can safely and effectively complete one-stage simple posterior TOPLL with 360-degree circular decompression. The incidence of complications is not high, and a good outcome can be obtained.

Resilience of infaunal ecosystems during the Early Triassic greenhouse Earth.

The Permian-Triassic mass extinction severely depleted biodiversity, primarily observed in the body fossil of well-skeletonized animals. Understanding how whole ecosystems were affected and rebuilt following the crisis requires evidence from both skeletonized and soft-bodied animals; the best comprehensive information on soft-bodied animals comes from ichnofossils. We analyzed abundant trace fossils from 26 sections across the Permian-Triassic boundary in China and report key metrics of ichnodiversity, ichnodisparity, ecospace utilization, and ecosystem engineering. We find that infaunal ecologic structure was well established in the early Smithian. Decoupling of diversity between deposit feeders and suspension feeders in carbonate ramp-platform settings implies that an effect of trophic group amensalism could have delayed the recovery of nonmotile, suspension-feeding epifauna in the Early Triassic. This differential reaction of infaunal ecosystems to variable environmental controls thus played a substantial but heretofore little appreciated evolutionary and ecologic role in the overall recovery in the hot Early Triassic ocean.

The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction.

The timing and nature of biotic recovery from the devastating end-Permian mass extinction (252 Ma) are much debated. New studies in South China suggest that complex marine ecosystems did not become re-established until the middle-late Anisian (Middle Triassic), much later than had been proposed by some. The recently discovered exceptionally preserved Luoping biota from the Anisian Stage of the Middle Triassic, Yunnan Province and southwest China shows this final stage of community assembly on the continental shelf. The fossil assemblage is a mixture of marine animals, including abundant lightly sclerotized arthropods, associated with fishes, marine reptiles, bivalves, gastropods, belemnoids, ammonoids, echinoderms, brachiopods, conodonts and foraminifers, as well as plants and rare arthropods from nearby land. In some ways, the Luoping biota rebuilt the framework of the pre-extinction latest Permian marine ecosystem, but it differed too in profound ways. New trophic levels were introduced, most notably among top predators in the form of the diverse marine reptiles that had no evident analogues in the Late Permian. The Luoping biota is one of the most diverse Triassic marine fossil Lagerstätten in the world, providing a new and early window on recovery and radiation of Triassic marine ecosystems some 10 Myr after the end-Permian mass extinction.

Simvastatin induces estrogen receptor-alpha expression in bone, restores bone loss, and decreases ERα expression and uterine wet weight in ovariectomized rats.

We previously reported that simvastatin induces estrogen receptor-alpha (ERα) in murine bone marrow stromal cells in vitro. In this study, we investigated the effect of simvastatin on ERα expression in bone and uterus in ovariectomized (OVX) rats and evaluated bone mass, bone strength, and uterine wet weight. Three-month-old Sprague-Dawley female rats received OVX or sham operation. Six weeks later, the rats were treated orally with simvastatin (5 or 10 mg/kg/day), or intraperitoneally with 17-ß-estradiol (E(2)) or a combination of simvastatin and E(2) for 6 weeks. Uterine wet weight, bone mineral density (BMD) of lumbar vertebrae, biomechanics of lumbar vertebrae, and induction of ERα expression in the bone and uterus were analyzed. The 6-week simvastatin treatment improved lumbar vertebral BMD and boosted biomechanical performance of the vertebral body compared to the OVX control, suggesting that simvastatin can treat osteoporosis caused by estrogen deficiency. More interestingly, simvastatin could increase ERα expression and synergy with estradiol in bone while antagonizing estradiol in the uterus, along with uterus atrophy and uterine wet weight decreases. In conclusion, these data suggest that simvastatin exert opposing modulatory effects on ERα expression on bone and uterus in ovariectomized rats, inducing ERα expression and synergy with estrogen to perform anabolic effects on the bones while decreasing E2 efficacy and uterine wet weight. This finding may be helpful to explain the mechanism of statin treatment in osteoporosis caused by estrogen deficiency.

[The impact of thoracic and thoracolumbar angular kyphosis on pelvic shape and sagittal alignment].

OBJECTIVE: To analyze the impact of thoracic and thoracolumbar angular kyphosis on pelvic shape and sagittal alignment. METHODS: From May 2002 to June 2010, the sagittal spino-pelvic parameters were analyzed in lateral standing radiographs of 32 patients (mean age 29.6 years) with thoracolumbar angular kyphosis. The parameters included Cobb angle of kyphosis, lumbar lordosis (LL), pelvic incidence (PI), sacrum slope (SS), pelvic tilt (PT) and sagittal vertical axis (SVA). All pelvic parameters in the patients were compared with those reported in historical normal subjects. All patients were treated by using kyphotic correction and fusion. The preoperative and postoperative parameters were compared. The pelvic parameters were also compared between the patients with kyphotic apex located at T(1-8) and those located at T(9-12) and thoracolumbar junction. The linear regression analysis was used to investigate the independent factors of PI. RESULTS: The mean kyphosis was 90.1° (31° - 138°). The mean age of kyphosis occurrence was 6.1 years. The mean PI, SS and PT were 34.8°, 35.8° and -0.7° respectively. The PI and PT were significantly smaller (P < 0.001) in the patients than those in normal subjects while the SS was similar. The kyphosis was improved to 27.9° post-operatively. There was no difference in PI values between pre-operation and postoperation (P > 0.05). The PI and SS in patients whose kyphosis located at thoracic spine (T(1-8)) were significantly higher than those at T(9)-L(2). Instead of patients' age and LL, the preoperative Cobb angle of kyphosis and the levels where kyphosis located were two independent impact factors of PI. CONCLUSIONS: The kyphosis occurred at childhood may influence pelvic shape and alignment significantly. The lower kyphotic apex located and the bigger kyphosis, the greater impact on the pelvic morphology. The surgery can improve the kyphosis, but can not change the sagittal pelvic morphology. Early treatment of thoracolumbar angular kyphosis is beneficial not only to reconstruction of spine alignment but also to the formation of sagittal pelvic morphology.

Mutational and bioinformatic analysis of haloarchaeal lipobox-containing proteins.

A conserved lipid-modified cysteine found in a protein motif commonly referred to as a lipobox mediates the membrane anchoring of a subset of proteins transported across the bacterial cytoplasmic membrane via the Sec pathway. Sequenced haloarchaeal genomes encode many putative lipoproteins and recent studies have confirmed the importance of the conserved lipobox cysteine for signal peptide processing of three lipobox-containing proteins in the model archaeon Haloferax volcanii. We have extended these in vivo analyses to additional Hfx. volcanii substrates, supporting our previous in silico predictions and confirming the diversity of predicted Hfx. volcanii lipoproteins. Moreover, using extensive comparative secretome analyses, we identified genes encodining putative lipoproteins across a wide range of archaeal species. While our in silico analyses, supported by in vivo data, indicate that most haloarchaeal lipoproteins are Tat substrates, these analyses also predict that many crenarchaeal species lack lipoproteins altogether and that other archaea, such as nonhalophilic euryarchaeal species, transport lipoproteins via the Sec pathway. To facilitate the identification of genes that encode potential haloarchaeal Tat-lipoproteins, we have developed TatLipo, a bioinformatic tool designed to detect lipoboxes in haloarchaeal Tat signal peptides. Our results provide a strong foundation for future studies aimed at identifying components of the archaeal lipoprotein biogenesis pathway.

[Characteristics of clinical findings and radiological assessment of high grade developmental spondylolisthesis].

OBJECTIVES: To investigate clinical appearance and radiological characteristics of high grade developmental spondylolisthesis and their significance. METHODS: In a retrospective study, a group of 6 female patients, who were diagnosed as high grade developmental spondylolisthesis and treated in Peking University third hospital from March 2007 to December 2008 were included. Clinical and radiological characteristics of the 6 patients were investigated and the following parameters were measured on standing lateral X-ray: PI (pelvic incidence), SK (sacral kyphosis) and LL (Lumbar lordosis). A series of 44 patients who came to out-patient department due to LBP and had no positive findings on lateral lumbar X-ray were selected as the control group. The four parameters were compared between study group and control group. Clinical meanings of significant difference were discussed. RESULTS: Clinical findings of high grade developmental spondylolisthesis included bending of knees, deformity of trunk and sciatica. Radiological appearances were characterized with kyphosis of lumbo-sacral joint, retroverted pelvis and domed sacrum. Spondylolisthesis patients has an average PI of (52 +/- 7) degrees which was significant higher than the control group [(43 +/- 8) degrees ] (P < 0.01). LL of study group [(51 +/- 10) degrees ] was higher than that of the control group [(18 +/- 9) degrees ] (P < 0.01) and SK of the study group [(12 +/- 11) degrees ] were lower than that of the control group [(21 +/- 10) degrees ] (P < 0.05). CONCLUSIONS: Characteristics of clinical findings of spondylolisthesis patients have obvious cosmetic appearance, significant pain and lower neurological deficits. Radiological characteristics display deformity of lumbo-sacral joint. PI, LL and SK are significant parameters for high grade spondylolisthesis.

[Morphological features of complicated thoracolumbar fractures and fixation technology of injured vertebra].

OBJECTIVES: To study the morphological feature of complicated thoracolumbar fractures and the fixation technology of injured vertebra. METHODS: From January 2005 to December 2007, 61 patients with type B and C thoracolumbar fractures according to AO classification were treated. There were 53 males and 8 females, with a mean age of 33.2 years (range, 9 to 65 years). Based on ASIA grading system of neurologic deficit, Grade A was found in 41 cases, grade B in 5 cases, Grade C in 5 cases, Grade D in 6 cases and Grade E in 4 cases. The injured vertebra located at thoracic region in 13, thoracolumbar in 39 and lumbar in 9 cases. The patients were divided into two groups: 32 cases with pedicle screws in the injured vertebra and 29 cases without pedicle screw in the injured vertebra. The analyses on the morphological features of injured vertebra were performed, and comparisons were carried out on the outcome regarding the reduction and correction of the injured vertebra, and the difference of Denis scale in pain domain and work status domain, between the two groups. RESULTS: All the patients were followed up for an average of 3 years (range, 1.5 to 4.5 years). There were significance statistical difference in the correction loss of Cobb angle, sagittal index, correction of dislocation index, and the Denis pain scale between the two groups (P < 0.05). A better outcome was observed in the injured vertebra fixation group than the injured vertebra non-fixation group. CONCLUSIONS: Inserting pedicle screws in the injured vertebra is effective and useful in the correction of complicated thoracolumbar fractures. It improves biomechanical stability of the spine after the operation.

[Clinical outcomes of surgical correction for ankylosing spondylitic kyphosis].

OBJECTIVE: To evaluate the clinical outcomes of posterior surgical corrective methods for ankylosing spondylitic kyphosis. METHODS: From June 2003 to June 2008, 21 cases of ankylosing spondylitic kyphosis received posterior surgical correction. There were 17 male and 4 female, and the average age was 39.5 years (range, 20 to 57 years). The total spine X-ray and CT were used to evaluate sagittal balance and thoracolumbar spine kyphosis angle, and chin brow-vertical angle was obtained from clinical lateral photograph. The surgical goal was to correct sagittal imbalance and chin brow-vertical angle. The simulated osteotomy was performed in computer before surgery to determine the correction methods. The surgical methods included: 16 cases of monosegmental closing osteotomy correction, 3 cases of anterior opening-posterior closing osteotomy correction, and 2 cases of combined pedicle subtraction osteotomy in thoracolumbar spine and Smith-Peterson osteotomy in lumbar spine. All patients were followed up after surgery, and the improvement of sagittal imbalance, chin brow-vertical angle and thoracolumbar spine kyphosis angle were assessed. The symptoms relief and satisfied rate were also evaluated. RESULTS: The average operation time was 4.4 hours, and the average blood loss was 1770 ml. Before surgery, the average thoracolumbar kyphosis angle was 62.1°, the average anterior shift of C(7) plumb line was 172.9 mm, and the average chin brow-vertical angle was 34.9°. The average follow-up was 28.8 months after surgery. The average correction rate of thoracolumbar kyphosis angle was 60%, the average improvement rate of anterior shift of C(7) plumb line was 64%, and the average correction rate of chin brow-vertical angle was 98%. The improvement rate of back pain was 64% during follow-up. The total surgical satisfactory rate was 95%. CONCLUSION: Based on the simulated osteotomy in computer before surgery, according to the characteristics of ankylosing spondylitic kyphosis, different posterior osteotomy and correction methods can achieve good results.

[Study of spinal sagittal plane curve in patients with thoracolumbar intervertebral disc herniation].

OBJECTIVE: To understand the curve of thoracolumbar junction in patients with thoracolumbar intervertebral disc herniation and analyze the relation between thoracolumbar intervertebral disc herniation and spinal sagittal curve. METHODS: The radiographic films of thoracolumbar junction of spine from 27 patients with thoracic disc herniation and 37 healthy persons as control were taken at reclining position. The Cobb angles of sagittal plane of thoracolumbar junction of spine were measured and statistically compared by SPSS (statistics package for social science). RESULTS: The Cobb angles of T10-L2, T10-L12 and T12-L2 in patients with thoracolumbar intervertebral disc herniation were greater than those in healthy controls respectively. CONCLUSION: The Cobb angles of sagittal plane of thoracolumbar junction of spine in patients with thoracolumbar intervertebral disc herniation are greater than those in healthy controls. The abnormal spinal curve is possibly responsible for thoracolumbar intervertebral disc herniation by abnormal biomechanical action.

[The study on correlation between intrusion of nucleus gelatinosus into vertebral body and low back pain after thoracolumbar fractures].

OBJECTIVE: To study the correlation between intrusion of nucleus gelatinosus into vertebral body and low back pain after thoracolumbar fractures. METHODS: One hundred and two patients who were treated in Peking university third hospital from January 2005 to September 2007 were evaluated retrospectively and included into this study. They were followed up for an average of 18 months and complete data were kept. Fifty-four patients were treated operatively and forty-eight patients were treated conservatively. VAS questionnaire was applied to evaluate the low back pain. Spearman Correlation Coefficients module and Wilcoxon 2-Sample Test module of SAS software were used to analyze the relation between intrusion of nucleus gelatinosus, different treatments, kyphotic Cobb angles and VAS. RESULTS: There were strong correlations between intrusion of nucleus gelatinosus and VAS in both operative group, P < 0.01 and non-operative group, P < 0.01; there were poor correlations between different treatments and VAS in both intrusion group, P > 0.05 and non-intrusion group, P > 0.05; and there were also poor correlations between Cobb angles and VAS, gamma = 0.2584, P > 0.05. CONCLUSION: There is correlation between the intrusion of nucleus gelatinosus into vertebral body and the low back pain after thoracolumbar fractures.

Efficacy and safety of antifibrinolytic agents in spinal surgery: a network meta-analysis.

BACKGROUND: Significant blood loss is still one of the most frequent complications in spinal surgery, which often necessitates blood transfusion. Massive perioperative blood loss and blood transfusion can create additional risks. Aprotinin, tranexamic acid (TXA), and epsilon-aminocaproic acid (EACA) are antifibrinolytics currently offered as prophylactic agents to reduce surgery-associated blood loss. The aim of this study was to evaluate the efficacy and safety of aprotinin, EACA, and low/high doses of TXA in spinal surgery, and assess the use of which agent is the most optimal intervention using the network meta-analysis (NMA) method. METHODS: Five electronic databases were searched, including PubMed, Cochrane Library, ScienceDirect, Embase, and Web of Science, from the inception to March 1, 2018. Trials that were randomized and compared results between TXA, EACA, and placebo were identified. The NMA was conducted with software R 3.3.2 and STATA 14.0. RESULTS: Thirty randomized controlled trial (RCT) studies were analyzed. Aprotinin (standardized mean difference [SMD]=-0.65, 95% credibility intervals [CrI;-1.25, -0.06]), low-dose TXA (SMD = -0.58, 95% CrI [-0.92, -0.25]), and high-dose TXA (SMD = -0.70, 95% CrI [-1.04, -0.36]) were more effective than the respective placebos in reducing intraoperative blood loss. Low-dose TXA (SMD = -1.90, 95% CrI [-3.32, -0.48]) and high-dose TXA (SMD = -2.31, 95% CrI [-3.75, -0.87]) had less postoperative blood loss. Low-dose TXA (SMD = -1.07, 95% CrI [-1.82, -0.31]) and high-dose TXA (SMD = -1.07, 95% CrI [-1.82, -0.31]) significantly reduced total blood loss. However, only high-dose TXA (SMD = -2.07, 95% CrI [-3.26, -0.87]) was more effective in reducing the amount of transfusion, and was significantly superior to low-dose TXA in this regard (SMD = -1.67, 95% CrI [-3.20, -0.13]). Furthermore, aprotinin (odds ratio [OR] = 0.16, 95% CrI [0.05, 0.54]), EACA (OR = 0.46, 95% CrI [0.22, 0.97]) and high dose of TXA (OR = 0.34, 95% CrI [0.19, 0.58]) had a significant reduction in transfusion rates. Antifibrinolytics did not show a significantly increased risk of postoperative thrombosis. Results of ranking probabilities indicated that high-dose TXA had the greatest efficacy and a relatively high safety level. CONCLUSIONS: The antifibrinolytic agents are able to reduce perioperative blood loss and transfusion requirement during spine surgery. And the high-dose TXA administration might be used as the optimal treatment to reduce blood loss and transfusion.