Terrestrial biota of Nishinoshima Island, the Ogasawara Islands, in 2021

西之島は2019年12月から2020年8月までの噴火により全域が溶岩と火山灰に被覆され、旧西之島由来の陸地のない完全な新島と言える状況となった。この島の陸上生物相の現状把握のため、2021年7月と9月に調査を行った。無人航空機による調査の結果、カツオドリ、アオツラカツオドリ、クロアジサシ、セグロアジサシ、オオアジサシの繁殖が確認された。陸上に設置した自動録音装置ではオナガミズナギドリの飛来が確認された。上陸地探索で上陸した北部の海岸ではカツオドリの死体は分解が進んでいなかったものの、死体下の砂礫からノミバエ類の蛹が確認されたほか、消化管内からハマゴウの種子が検出された。このほか菌類らしき構造が確認されたが、植物は確認されなかった。海鳥の繁殖成功度は低く、現在の西之島はエコロジカルトラップになっている可能性がある。海鳥は重要な生態系機能を持ち生態系成立プロセスに大きな影響を与えるため、初期の鳥類相変化のモニタリングが不可欠である。The eruption from December 2019 to August 2020 had covered the entire area of Nishinoshima with lava and volcanic ash, making it a completely new island without land derived from the former Nishinoshima. In order to clarify the current status of the terrestrial biota on this island, we conducted surveys in July and September 2021. As a result of the survey using unmanned aerial vehicles, we confirmed the breeding of the brown booby, masked booby, brown noddy, sooty tern and great-crested tern. The arrival of the wedgetailed shearwater was confirmed by using acoustic recorders located on the island. The carcass of a brown booby found on the northern beach had not decomposed, but pupae of Phoridae fly were identified in the sand under the carcass, and Vitex rotundifolia seeds were found in the digestive tract of the carcass. In addition, fungus-like structures were observed, but no plants were found. The breeding success of seabirds seemed very low, and Nishinoshima might be an ecological trap. Since seabirds have important ecological functions and greatly influence the process of ecosystem establishment of Nishinoshima, it is essential to monitor the initial avifaunal changes.departmental bulletin pape

Lateral Lumbar Interbody Fusion for Ossification of the Yellow Ligament in the Lumbar Spine: First Reported Case

When ossification of the yellow ligament (OYL) occurs in the lumbar spine and extends to the lateral wall of the spinal canal, facetectomy is required to remove all of the ossified lesion and achieve decompression. Subsequent posterior fixation with interbody fusion will then be necessary to prevent postoperative progression of the ossification and intervertebral instability. The technique of lateral lumbar interbody fusion (LLIF) has recently been introduced. Using this procedure, surgeons can avoid excess blood loss from the extradural venous plexus and detachment of the ossified lesion and the ventral dura mater is avoidable. We present a 55-year-old male patient with OYL at L3/4 and anterior spondylolisthesis of L4 vertebra, with concomitant ossification of the posterior longitudinal ligament, who presented with a severe gait disturbance. He underwent a 2-stage operation without complications: LLIF for L3/4 and L4/5 was performed at the initial surgery, and posterior decompression fixation using pedicle screws from L3 to L5 was performed at the second surgery. His postoperative progress was favorable, and his interbody fusion was deemed successful. Here, we present the first reported case of LLIF for OYL of the lumbar spine. This procedure can be a good option for OYL of the lumbar spine

A case of thoracic disc herniation characterized by marked posture-related dynamic changes in neurological symptoms

Thoracic disc herniation is less common than lumbar and cervical disc herniations. It is usually accompanied by severe myelopathy, which often leads to surgery. Because the thoracic spine is less mobile, thoracic disc herniation is considered to be minimally affected by dynamic spine factors in cases with myelopathy. We experienced a case of thoracic disc herniation (T4/5 and T6/7) characterized by posture-related dynamic changes in neurological symptoms; that is, numbness extending from the trunk to the entire lower limbs was deteriorated in the standing and sitting positions, was relieved in the supine position, and disappeared in the prone position. In addition, the patient reported dysuria with a delay when attempting to urinate in the standing position. Computed tomographic myelography revealed diffuse idiopathic skeletal hyperostosis extending from T3 to T11, and the kyphosis angles at T1 to T11 levels were 68 degrees in the half-sitting position and 58 degrees in the prone position, showing posture-related changes. The patient underwent the posterior fusion in the prone position, by which symptoms disappeared, without undergoing disc herniotomy or laminectomy, and favorable outcomes were achieved. Thoracic disc herniation with marked posture-related neurological symptoms is extremely rare. Here we report a case presentation and literature review of pathophysiology observed in our patient

UAV-based exploratory survey of invertebrates on Nishinoshima Island

西之島は2013年以降断続的に噴火を繰り返しており、2017年からは毎年噴火が記録されている。特に2019年12月からの激しい噴火以降は火山活動への警戒により、島のほぼ全てのエリアで上陸調査ができない状況が続いている。しかし、その期間中も西之島では生態系遷移が進むと考えられる。そこで無人航空機（UAV）を活用することにより、遠隔からの生態系モニタリングを実施することとした。小型の無脊椎動物については撮影調査による情報収集が難しいことから、粘着トラップ、吸引機、採水器をUAV で運搬して試料を採集する新規の手法により調査を試みた。粘着トラップではカクレイワガニとシラミバエの1種が捕獲され、採水サンプルの環境DNA解析では軟体動物、棘皮動物のDNA が検出された。生態系遷移の初期段階を明らかにするための調査においては網羅的な生物群の時間的変化を記録することが重要である。火山活動が続く西之島において安全に生態系モニタリングを継続するためにUAVを活用した多様な生物の探索技術は重要な手段となりうる。Nishinoshima Island has been volcanically active since 2013, with eruptions recorded every year since 2017. Especially since the severe eruption in December 2019, almost all areas of the island cannot be surveyed ashore due to the warnings of volcanic activity. However, ecological succession on Nishinoshima Island may continue to progress even during the period. We utilised UAVs to carry out remote ecosystem monitoring. As it is difficult to collect information on small invertebrates by photographing surveys, we tried new methods for collecting samples by transporting a sticky trap, a vacuum cleaner and a water sampler using a UAV. Geograpsus grayi and Olfersia sp. were captured in the sticky traps. Environmental DNA analysis of the collected water samples detected molluscs and echinoderms. It is important to record temporal changes of a comprehensive biological dataset in order to clarify the earliest stages of ecosystem succession on oceanic islands. Various biological survey techniques using UAVs can be important tools for safely conducting continuous implementation of ecosystem monitoring on Nishinoshima Island, where volcanic activity is continuing.departmental bulletin pape

Visualization of walking speed variation-induced synchronized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles with a newly developed gait analysis system

Purpose:To evaluate a newly developed system for dynamic analysis of gait kinematics and muscle activity.Methods:We recruited 10 healthy men into this study. Analyses of three-dimensional motion and wireless surface electromyogram (EMG) were integrated to achieve synchronous measurement. The participants walked continuously for 10 min under two conditions: comfortable and quick pace. Outcome measures were joint angles of the lower limbs determined from reflective markers and myoelectric activity of trunk and lower limbs determined from EMG sensors, comparing comfortable and quick gait pace.Results:Lower limb joint angle was significantly greater at the quick pace (maximum flexion of the hip joint: 4.1°, maximum extension of hip joint: 2.3°, and maximum flexion of the knee joint while standing: 7.4°). The period of maximum flexion of the ankle joint during a walking cycle was 2.5% longer at a quick pace. EMG amplitudes of all trunk muscles significantly increased during the period of support by two legs (cervical paraspinal: 55.1%, latissimus dorsi: 31.3%, and erector spinae: 32.6%). EMG amplitudes of quadriceps, femoral biceps, and tibialis anterior increased significantly by 223%, 60.9%, and 67.4%, respectively, between the periods of heel contact and loading response. EMG amplitude of the gastrocnemius significantly increased by 102% during the heel-off period.Conclusion:Our gait analysis synchronizing three-dimensional motion and wireless surface EMG successfully visualized dynamic changes in lower limb joint angles and activity of trunk and lower limb muscles induced by various walking speeds

Cervical restenosis caused by progressive ossification of the posterior longitudinal ligament in patients following laminoplasty: Two case reports

We report two cases of restenosis caused by the progression of thickness of ossification of the posterior longitudinal ligament (OPLL) seven and more years after laminoplasty, resulting in neurological deterioration needed for revision anterior decompressive surgeries. Neurological recovery after revision anterior excision of OPLL was poor. In both cases, the patients had progressive OPLL, with a non-ossified segment of the ossification foci, in common. After laminoplasty, they also both exhibited osseous fusion of the elevated laminae, but there was discontinuity at the interlaminar space at the peak level of OPLL. Discontinuity of the osseous fusion in the elevated laminae might cause mechanical stress increases at the non-ossified segment of the OPLL and could lead to the progression of OPLL. The present cases showed that long-term progression of OPLL can induce neurological deterioration even after sufficient posterior decompression by laminoplasty. Therefore, when considering risk factors that may be predictive of the progression of OPLL after laminoplasty, it is important to perform strict follow-up examination to check for progression to reduce the risk of myelopathy symptoms that are indicative of neurological deterioration