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Introduction: Basilar invagination (BI) is a common deformity in the occipitocervical region. The traditional surgical method of BI is direct transoral decompression followed by posterior decompression and fixation. Posterior-only decompression and fixation have achieved good efficacy in the treatment of BI in recent years, but complications are common due to the operation in the upper cervical vertebra and the medulla oblongata region. Moreover, posterior-only occipitocervical fusion combined with an intraoperative 3-dimensional (3D) navigation system is relatively rare, and reports of this procedure combined with 3D printing technology have not been published. We present a case of BI treated with posterior-only occipitocervical fusion combined with 3D printing technology and 3D navigation system to reduce the risk of surgical complications. Patient Concerns: A 55-year-old patient with a history of neck pain and numbness of the extremities for 6 years developed a walking disorder for 1 year. Diagnoses: Atlantoaxial dislocation with BI. Interventions: The patient underwent posterior-only occipitocervical fusion combined with intraoperative 3D navigation system and 3D printing technology. Outcomes: The patient's walking disorder was resolved and he was able to walk approximately 100 m by himself when he was allowed to get up and move around with the help of a neck brace. At 6 months postoperatively, the patient reported that the numbness of the limbs was reduced, and he could walk >500 m by himself. Conclusion: Occipitocervical fusion is one of the established techniques for the treatment of BI. The biggest advantage of the 2 technologies was that it ensured precise implant placement. The advantages of intraoperative 3D navigation systems are as follows: real-time intraoperative monitoring of the angle and depth of implant placement; the best nailing point can be determined at the time of implantation, rather than according to the operator's previous experience; and the extent of screw insertion is visible to the naked eye, rather than being dependent on the “hand feel” of the surgeon. At the same time, the 3D printing technology can be applied to clarify the relationship between blood vessels and bone around the implant to minimize injury to important structures during implantation.

Rationale: Cauda equina syndrome (CES) refers to a group of symptoms that occur when the nerves in the cauda equina become compressed or damaged. The most common etiology of CES is lumbar intervertebral disc herniation, but CES following lumbar spinal surgery is rare, especially without motor dysfunction. Herein, we illustrate a case of CES that developed as a complication of spinal surgery and to deduce its possible underlying cause. Patient concerns: A 46-year-old man experienced lumbago, bilateral shank pain, and numbness with neurogenic claudication for 3 years due to degenerative lumbar disc herniation and spinal cord stenosis. After a thorough examination to diagnose lumbar spinal stenosis, the patient underwent bilateral decompression and pedicle screw system internal fixation with bone graft. Postoperatively, the patient showed regained strength in his bilateral shanks, and he did not complain of lumbago and shank pain, but CES occurred, which manifested as underpants-type numbness in the perineum without bladder, anal, and motor dysfunction. Diagnoses: CES as a postoperative complication of lumbar stenosis. Interventions: The patient underwent bilateral laminectomies, partial facetectomies, and pedicle screw system internal fixation and fusion with bone graft. Postoperatively, the patient performed adequate rehabilitation exercises and was expected to recover spontaneously. Outcomes: The symptoms of pain and claudication resolved after 3 weeks in the hospital, but an underpants-type hypoesthesia in the perineum without motor dysfunction developed. The patient experienced full recovery from CES 6 months after surgery. Lessons: CES as a complication of lumbar spinal surgery is very rare. Excessive sensitivity to the traction of the dural sac was, in our opinion, the most possible cause of postoperative CES in this case. When the nerve root is pulled intraoperatively, it is best not to cross the central line of the spinous process. The plane of the nerve retractor needs to be parallel to the dural sac at the pulling point to reduce the formation of shear force. Most importantly, gentle maneuver is required because sensitivity to the traction of the dural sac varies individually.

Introduction: Traditional open discectomy and intervertebral fusion surgery is the common strategy for lumbar disc herniation (LDH). However, it has the disadvantages of long recovery time and severe paravertebral soft tissue injury. Zina percutaneous screw fixation combined with endoscopic lumbar intervertebral fusion (ZELIF), as a novel minimally invasive surgical technique for LDH, has the advantages in quicker recovery, less soft tissue destruction, shorter hospital stays and less pain. We report a novel technique of ZELIF under intraoperative neuromonitoring (INM) for the treatment of LDH. Patient concerns: A 51-year-old male presented to our hospital with left lower extremity pain and numbness for 1 year. Diagnosis: Lumbar disc herniation (LDH). Interventions: This patient was treated with Zina percutaneous screw fixation combined with endoscopic neural decompression, endplate preparation, and intervertebral fusion through Kambin's triangle. Each step of the operation was performed under INM. Outcomes: The follow-up period lasted 12 months; the hospitalization lasted 4 nights; the blood loss volume was 65 ml, and the time of operation was 266 min. INM showed no neurological damage during the surgery. No surgical complications, including neurological deterioration, cage migration, non-union, instrumentation failure or revision operation, were observed during the follow-up period. Visual Analogue Scale (VAS) score reduced from 7 to 1; the Oswestry Disability Index (ODI) decreased from 43 to 14; the EQ-5D score was 10 preoperatively and 15 at the final follow-up visit; the Physical Component Summary of the 36-Item Short Form Health Survey (SF-36) was 48 preoperatively and 49 at the last follow up visit; the SF-36 Mental Component Summary was 47 before surgery and decreased to 41 postoperatively. Conclusion: ZELIF under INM may represent a feasible, safe and effective alternative to endoscopic intervertebral fusion and percutaneous screw fixation, for decompressing the lumbar's exiting nerve root directly with minimal invasion in selected patients.

Due to rapid global warming, the relationship between the mass loss of the Antarctic ice sheet and rising sea levels are attracting widespread attention. The Lambert–Amery glacial system is the largest drainage system in East Antarctica, and its mass balance has an important influence on the stability of the Antarctic ice sheet. In this paper, the recent ice flux in the Lambert Glacier of the Lambert–Amery system was systematically analyzed based on recently updated remote sensing data. According to Landsat-8 ice velocity data from 2018 to April 2019 and the updated Bedmachine v2 ice thickness dataset in 2021, the contribution of ice flux approximately 140 km downstream from Dome A in the Lambert Glacier area to downstream from the glacier is 8.5 ± 1.9, and the ice flux in the middle of the convergence region is 18.9 ± 2.9. The ice mass input into the Amery ice shelf through the grounding line of the whole glacier is 19.9 ± 1.3. The ice flux output from the mainstream area of the grounding line is 19.3 ± 1.0. Using the annual SMB data of the regional atmospheric climate model (RACMO v2.3) as the quality input, the mass balance of the upper, middle, and lower reaches of the Lambert Glacier was analyzed. The results show that recent positive accumulation appears in the middle region of the glacier (about 74–78°S, 67–85°E) and the net accumulation of the whole glacier is 2.4 ± 3.5. Although the mass balance of the Lambert Glacier continues to show a positive accumulation, and the positive value in the region is decreasing compared with values obtained in early 2000.