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Currently, Unilateral biportal endoscopy is widely used in the surgical treatment of lumbar spinal stenosis. To investigate the feasibility of bilateral synchronous UBE to unilateral laminotomy and bilateral decompression(BS-UBE-ULBD) for treating two-level lumbar spinal stenosis (LSS). Sixty-four patients with two-level lumbar spinal stenosis (LSS) treated with BS-UBE-ULBD from October 2022 to January 2024 were retrospectively analyzed. All patients were treated with BS-UBE-ULBD. All 64 patients successfully underwent surgery, and the duration of surgery was 95–180 min, with an average of 119.92 ± 14.79 min. The average number of fluoroscopy was 3.02 ± 0.92. The average blood loss during the surgery was 73. 44 ± 36.70 ml. Postoperative lumbar CT showed that the spinal canal and bilateral nerve roots were fully decompressed. There were no postoperative complications, such as infection, severe nerve root injury, and lumbar instability. Complete follow-up data were obtained for all 64 cases. The VAS score of low back and leg pain and the ODI of lumbar function significantly (P < 0.05) improved at each follow-up time point. MacNab evaluation at 6 months after the surgery showed that the results were excellent in 48 cases, good in 14 cases, and fair in 2 cases. The excellent and good rate was 96. 88% (62/64). So BS-UBE-ULBD is a minimally invasive, highly effective, and safe procedure for 2-level LSS. Degenerative lumbar spinal stenosis (LSS) refers to clinical symptoms caused by the compression of the cauda equina, nerve root, and vascular complex. LSS can occur due to the abnormal shape and volume of the bony or fibrous structure after degenerative changes and the stenosis of the inner diameter of one or more lumens at a single level or multiple levels. It is a common cause of lumbago or lumbago and leg pain, which is common among middle-aged and elderly people1. LSS has become the most common cause of lumbar surgery among patients over 60 years of age2. However, traditional surgery necessitates extensive stripping of paraspinal muscles, which can easily lead to the ischemic injury of paraspinal muscles and atrophy after denervation. Therefore, traditional surgery may result in intractable back pain, stiffness, and discomfort after surgery3,4. Furthermore, as the posterior bone and soft tissue structures need to be extensively resected during the surgery, epidural scar and nerve compression are highly likely after the surgery. The high risk of general anesthesia cannot be ignored among elderly and weak patients2,5. Recently, with the rapid development of minimally invasive spine surgery, endoscopic surgery has been applied in the treatment of LSS6. Unilateral biportal endoscopy (UBE) is more popular in treating LSS and is a more flexible operation, with small trauma, quick recovery, and a gentle learning curve. In addition, many studies have proven the good clinical efficacy of unilateral biportal endoscopy7. Multilevel spinal stenosis can be done simultaneously. Previously, the same operator decompressed multiple segments in turn8,9, but the operation lasted longer, and the corresponding problems, such as bleeding, high risk of anesthesia, and fluoroscopy frequency, increased. From October 2022 to June 2024, our hospital pioneered the use of Bilateral Synchronous UBE-unilateral Laminotomy and Bilateral Decompression (BS-UBE-ULBD) for two-level degenerative LSS. Sixty-four patients with two-segment LSS were treated with BS-UBE-ULBD, and the results were satisfactory. [ABSTRACT FROM AUTHOR]

Purpose: One-hole Split Endoscopy (OSE) is a newer surgical modality that can be applied to posterior cervical foraminotomy (PCF), lumbar discectomy, laminectomy, and decompression. It incorporates intervertebral foraminotomy, open surgery, and other lumboendoscopic techniques with a wide observation field, free space, and compatibility with various spinal surgical techniques and instruments. This study investigated the clinical efficacy of minimally invasive posterior cervical nucleus pulposus removal for cervical spondylotic radiculopathy (CSR) by OSE-Keyhole technique. Patients and Methods: This was a retrospective study of 63 patients treated with OSE keyhole treatment for CSR between May 2021 and September 2023 at Qilu Hospital of Shandong University, Qilu Hospital of Shandong University (Qingdao, China), and Second Hospital of Shandong University, respectively. Clinical outcomes included patients' preoperative and postoperative visual analogue scale (VAS) - arm and neck, Japanese Orthopaedic Association Assessment Treatment Score (JOA) - cervical spine, which were collected at baseline, two days postoperatively, one month postoperatively, and three months postoperatively after the last follow-up visit for evaluation, and perioperative indicators, including intraoperative bleeding, length of hospital stay, postoperative complications, and reoperations, which were also collected. Results: Statistical analyses were performed for the baseline data and follow-up results of 63 patients. Compared to the preoperative baseline values, the follow-up results two days, one month and three months after surgery showed significant improvements in vas-arm, neck and JOA scores in the operated patients (P< 0.05) as well as a reduction in all perioperative-related indices. Conclusion: In the treatment of cervical pain and disability due to radiculopathy, OSE keyhole removal of the posterior cervical nucleus pulposus is a better clinical option as it is less invasive and recovers better postoperatively. [ABSTRACT FROM AUTHOR]

As one of the paramount components of Asian monsoon and global atmospheric circulation system, the ISM (Indian summer monsoon) plays a vitally important role in the natural environment, ecological balance, and cultural development. Moreover, understanding the ISM could provide valuable insights into global hydrological, atmospheric, and carbon cycles. In recent decades, many ISM records based on different archives have been established within the Holocene, however, issues still remain: the TP (Tibetan Plateau) and the Indian subcontinent are often analyzed separately, despite the both are strongly influenced by the ISM, impeding comprehensive understanding of the monsoon and its object relationship with the East Asian summer monsoon (EASM). Here, covering the both regions, 65 published paleoclimate records within the Holocene have been collected, and conclusions are drawn as follow: (1) There are two evolution patterns of the ISM during the Holocene. The first pattern with the Holocene Optimum (HO) at ~10–6 ka BP, mainly distributing in the Arabian Sea and its surrounding areas, the Indian subcontinent, western central TP, northern TP, and southern China. The second pattern with the HO at ~8–3 ka BP, mainly distributing in the Bay of Bengal and its surrounding areas and southern TP. (2) The delay between the optimum of the second pattern and insolation maximum may be caused by the variation of high-latitude ice cover, although the underlying mechanism concerning the spatial distribution of the two patterns is still unclear. (3) The ISM and the EASM evolve synchronously, and share similar pattern divergence. Arguments over this issue mainly owe to the selected records originating from different patterns. This study makes up the gap in the pattern divergence of monsoon evolution, deepening the understanding of the ISM, even entire Asian monsoon system, and therefore is of great significance for future climate prediction. [ABSTRACT FROM AUTHOR]

The tectonic evolution of the Paleo‐Jinshajiang Ocean, and in particular the time of its closure, is debated. Here we present new constraints on the evolution of this region from an integrated paleomagnetic and geochronologic study of the Late Triassic Batang Group volcanic rocks in Qamdo, Eastern Qiangtang Terrane (EQT). Two zircon U‐Pb ages indicate that the volcanic rocks erupted at ∼227–222 Ma. New paleomagnetic results yield a robust Late Triassic paleopole of 57.6°N, 176.4°E (A95 = 7.8°), corresponding to a paleolatitude of 32.5 ± 7.8°N for the study area. Integrated with other lines of paleomagnetic and geological evidence, we show that the northward drift of the EQT placed it at the same paleolatitude as the Tarim Block by ∼227–222 Ma, which suggests that the Paleo‐Jinshajiang Ocean in the Qamdo region closed before that time, and likely around ∼230 Ma. Plain Language Summary: The closure of the Paleo‐Jinshajiang Ocean, which was one of the most important ancient oceans of Asia, closed when the Qiangtang Terrane (QT) collided with the terranes now located to the north of it. However, the evolution of this ocean, and especially the timing of its closure, are still debated. The drift history of the QT is a key to understanding the evolution of the Paleo‐Jinshajiang Ocean. We present here new constraints on the evolution of this region from an integrated paleomagnetic and zircon U‐Pb geochronologic study of Late Triassic volcanic rocks in Qamdo, Eastern QT. Two zircon U‐Pb geochronologic results indicate that the volcanic rocks erupted at ∼227–222 Ma. New paleomagnetic results yield a robust Late Triassic paleopole of 57.6°N and 176.4°E, and indicate that the study area was then located at a paleolatitude of 32.5 ± 7.8°N. In integrating these data with other lines of evidence, we show that a northward drift of the EQT since the early Permian brought it to the same paleolatitude as the Tarim Block by ∼227–222 Ma. This implies that the closure of the Paleo‐Jinshajiang Ocean in the Qamdo region occurred before 227–222 Ma, and likely around ∼230 Ma. Key Points: Volcanic rocks of the Late Triassic Batang Group are dated by U‐Pb on zircon to ∼227–222 MaPaleomagnetic data from these rocks yield a robust Late Triassic paleopole of 57.6°N, 176.4°E(A95 = 7.8°)Closure of the Paleo‐Jinshajiang Ocean occurred before 227–222 Ma, and likely around ∼230 Ma [ABSTRACT FROM AUTHOR]

The tectonic evolution of the eastern Paleo‐Tethys in the Three‐Rivers headwater region remains uncertain, especially because of the lack of quality paleomagnetic data from the east Eastern Qiangtang Terrane (EQT). Here, we present an integrated paleomagnetic and zircon U‐Pb geochronologic study of the Gadikao Formation (Fm.) volcanic rocks in the EQT. This previously assumed Carboniferous or Permian rock unit is now zircon U‐Pb dated to ∼254–248 Ma. Our new high quality (29 sites and 257 samples) inferred primary paleomagnetic results yield a robust Permo‐Triassic boundary paleopole of 59.7°N and 228.2°E (A95 = 3.3°), with a paleolatitude of 10.0 ± 3.3°N for the study area. Integrated with other reliable Permo‐Triassic paleomagnetic data of the EQT and the Tarim Block and other lines of geologic evidence, we propose that the EQT drifted continuously northward during 300–200 Ma and the Paleo‐Tethys Ocean probably closed at ∼232–220 Ma around the Qamdo region, most likely at 230 Ma. Plain Language Summary: The drift history of the Qiangtang Terrane is the key to understand the evolution of the "Proto‐Tibet" and the Paleo‐/Meso‐Tethys Oceans, which is still under debate. In this work, we provide U‐Pb zircon data to constrain (254–248 Ma) a high quality paleomagnetic pole (59.7°N, and 228.2°E, with A95 = 3.3°) for the EQT, which was located at ∼10.0°N during ∼254–248 Ma. Integrated with other available lines of evidence, we propose that the EQT drifted continuously northward during the Permian and Triassic and collided with the Songpan‐Ganzi/Tarim Terrane, resulting in the closure of the Paleo‐Tethys Ocean around the Qamdo region during ∼232–220 Ma, most likely at about 230 Ma. Key Points: The previous upper Paleozoic Gadikao Formation yields high precision Zircon U‐Pb dates from ∼254 to 248 MaThe volcanic rocks yield a robust Permo‐Triassic boundary paleopole of 59.7°N and 228.2°E (A95 = 3.3°)The closure of the Paleo‐Tethys Ocean around Qamdo is best estimated at ∼232–220 Ma, mostly likely at ∼230 Ma [ABSTRACT FROM AUTHOR]

Background: Recently, the excellent outcomes of temporary fixation of C1-2 without fusion in the treatment of odontoid fracture had been reported. It is still unclear if this technique could achieve the equivalent outcomes as the golden standard technique of anterior screw fixation. The objective of this study is to compare the clinical outcome of two treatments of fresh type II odontoid fracture: anterior cannulated screws fixation (ACSF) versus posterior instrumentation of C1-2 without fusion (PIWF). Methods: This is a retrospective study. This series included 28 males and 8 females, and the mean age was 41.5 years (range, 22 to 70 years). Eleven patients were treated with ACSF, and 25 patients with PIWF. For PIWF, the implants were removed after fracture union was confirmed at 0.75~1.5 years later. All patients underwent preoperative and serial postoperative clinical examinations at approximately 3 months, 6 months, and annually thereafter. The neck disability index (NDI) was used to assess the neck discomfort caused by the operation. The range of rotary motion was evaluated at each visit. All fractures were reassessed postoperatively with serial X-films and CT scans of the cervical spine at each follow-up visit, to evaluate screw position, fracture alignment, and fusion status. Results: All patients achieved immediate spinal stabilization after surgery, and none experienced neurologic deterioration. The follow-up periods ranged from 24 to 60 months. The average range of neck rotation was dramatically lost in PIWF after fixation (46° and 89° respectively in ACSF and PIWF), and recovered to 83° after the implant was removed. The NDI in PIWF was statistically higher than that in ACSF (5 and 13% respectively in ACSF and PIWF) after the first operation and decreased to 8% 1 year after the secondary operation. The fusion rates were 90.9 and 96% respectively in ACSF and PIWF. Both groups had a case of fracture non-union. Conclusions: For fresh type II odontoid fractures, high rate of fracture union can be achieved by both ACSF and PIWF. For most fresh type II odontoid fractures, anterior screw fixation was the best option for its simplicity and preservation of normal atlanto-axial rotary function. Posterior instrumentation without fusion could preserve most of the atlanto-axial rotary function and lead to moderate neck discomfort and is also a good alternative if anterior screw fixation is contraindicated. [ABSTRACT FROM AUTHOR]

With the aging population, osteoporosis, which leads to poor fusion, has become a common challenge for lumbar surgery. In addition, most people with osteoporosis are elderly individuals with poor surgical tolerance, and poor bone quality can also weaken the stability of internal fixation. This study compared the fixation strength of the bilateral traditional trajectory screw structure (TT-TT), the bilateral cortical bone trajectory screw structure (CBT-CBT), and the hybrid CBT-TT (CBT screws at the cranial level and TT screws at the caudal level) structure under different bone mineral density conditions. A finite element (FE) analysis study. Above all, we established a healthy adult lumbar spine model. Second, under normal and osteoporotic conditions, three transforaminal lumbar interbody fusion (TLIF) models were established: bilateral traditional trajectory (TT-TT) screw fixation, bilateral cortical bone trajectory (CBT-CBT) screw fixation, and hybrid cortical bone trajectory screw and traditional trajectory screw (CBT-TT) fixation. Finally, a 500-N compression load with a torque of 10 N/m was applied to simulate flexion, extension, lateral bending, and axial rotation. We compared the range of motion (ROM), adjacent disc stress, cage stress, and posterior fixation stress of the different fusion models. Under different bone mineral density conditions, the range of motion of the fusion segment was significantly reduced. Compared to normal bone conditions, the ROM of the L4–L5 segment, the stress of the adjacent intervertebral disc, the surface stress of the cage, and the maximum stress of the posterior fixation system were all increased in osteoporosis. Under most loads, the ROM and surface stress of the cage and the maximum stress of the posterior fixation system of the TT-TT structure are the lowest under normal bone mineral density conditions. However, under osteoporotic conditions, the fixation strength of the CBT-CBT and CBT-TT structures are higher than that of the TT-TT structures under certain load conditions. At the same time, the surface stress of the intervertebral fusion cage and the maximum stress of the posterior fixation system for the two structures are lower than those of the TT-TT structure. Under normal bone mineral density conditions, transforaminal lumbar interbody fusion combined with TT-TT fixation provides the best biomechanictability. However, under osteoporotic conditions, CBT-CBT and CBT-TT structures have higher fixed strength compared to TT-TT structures. The hybrid CBT-TT structure exhibits advantages in minimal trauma and fixation strength. Therefore, this seems to be an alternative fixation method for patients with osteoporosis and degenerative spinal diseases. This study provides biomechanical support for the clinical application of hybrid CBT-TT structure for osteoporotic patients undergoing TLIF surgery. [ABSTRACT FROM AUTHOR]