Physical Properties of Oxide Films Formed by Plasma Anodization on Mg Alloy

Lee, Sung-Hyung,Yashiro, Hitoshi,Aoki, Kazuki,Nanao, Hidetaka,Kure-Chu, Song-Zhu Materials Research Society of Korea 2019 한국재료학회지 Vol.29 No.11

In this work, we study physical and mechanical properties of oxide films formed on AZ91D magnesium alloy by plasma anodization at different temperatures. It is found that the higher the electrolyte temperature, the lower is the breakdown voltage of oxide layer. This is probably because films formed at higher temperatures are thinner and denser. Moreover, electrolyte temperature plays an important role in the physical properties of the films. As the electrolyte temperature increases from 20 to $50^{\circ}C$, the hardness of the oxide layer increases. Friction test against steel balls indicates that wear scars become narrower for films formed at higher temperatures because the films are harder, as indicated by the Vickers hardness. The thinner and denser nature of the oxide film formed at $50^{\circ}C$ is also advantageous for heat transfer when film is used as a heat sink. Laser flash test results show very fast heat transfer for AZ91D with plasma anodized oxide layer formed at higher temperatures.

Change of Lumbar Ligamentum Flavum after Indirect Decompression Using Anterior Lumbar Interbody Fusion

Seiji Ohtori,Sumihisa Orita,Kazuyo Yamauchi,Yawara Eguchi,Yasuchika Aoki,Junichi Nakamura,Masayuki Miyagi,Miyako Suzuki,Gou Kubota,Kazuhide Inage,Takeshi Sainoh,Jun Sato,Kazuki Fujimoto,Yasuhiro Shiga 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.1

Study Design: Retrospective case series. Purpose: The purpose of this study was to examine changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a 10-year follow-up. Overview of Literature: Extreme lateral interbody fusion provides minimally invasive treatment of the lumbar spine; this anterior fusion without direct posterior decompression, so-called indirect decompression, can achieve pain relief. Anterior fusion may restore disc height, stretch the flexure of the ligamentum flavum, and increase the spinal canal diameter. However, changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a long follow-up have not yet been reported. Methods: We evaluated 10 patients with L4 spondylolisthesis who underwent stand-alone anterior interbody fusion using the iliac crest bone. Magnetic resonance imaging was performed 10 years after surgery. The cross-sectional area (CSA) of the dural sac and the ligamentum flavum at L1–2 to L5–S1 was calculated using a Picture Archiving and Communication System. Results: Spinal fusion with correction loss (average, 4.75 mm anterior slip) was achieved in all patients 10 years postsurgery. The average CSAs of the dural sac and the ligamentum flavum at L1–2 to L5–S1 were 150 mm2 and 78 mm2, respectively. The average CSA of the ligamentum flavum at L4–5 (30 mm2) (fusion level) was significantly less than that at L1–2 to L3–4 or L5–S1. Although patients had an average anterior slip of 4.75 mm, the average CSA of the dural sac at L4–5 was significantly larger than at the other levels. Conclusions: Spinal stability induced a lumbar ligamentum flavum change and a sustained remodeling of the spinal canal, which may explain the long-term pain relief after indirect decompression fusion surgery.

Do Physical Symptoms Predict the Outcome of Surgical Fusion in Patients with Discogenic Low Back Pain?

Seiji Ohtori,Sumihisa Orita,Kazuyo Yamauchi,Yawara Eguchi,Yasuchika Aoki,Junichi Nakamura,Masayuki Miyagi,Miyako Suzuki,Gou Kubota,Kazuhide Inage,Takeshi Sainoh,Jun Sato,Yasuhiro Shiga,Koki Abe,Kazuki 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.3

Study Design: Retrospective case series. Purpose: To determine whether symptoms predict surgical outcomes for patients with discogenic low back pain (DLBP). Overview of Literature: Specific diagnosis of DLBP remains difficult. Worsening of pain on flexion is a reported symptom of DLBP. This study sought to determine whether symptoms predict surgical outcomes for patients with DLBP. Methods: We investigated 127 patients with low back pain (LBP) and no dominant radicular pain. Magnetic resonance imaging was used to select patients with disc degeneration at only one level. If pain was provoked during discography, we performed fusion surgery (87 patients). Visual analogue scale score and responses to a questionnaire regarding symptoms including worsening of pain on flexion or extension were assessed. Symptom sites before surgery were categorized into LBP alone, or LBP plus referred inguinal or leg pain. We followed 77 patients (average 3.0 years) and compared symptoms before surgery with surgical outcome. Results: Sixty-three patients with a good outcome showed postsurgical pain relief (≥60% pain relief) and 14 patients with a poor outcome did not (<60% pain relief). In patients with good outcomes, worsening of LBP was evident in 65% of cases on flexion and in 35% on extension. However, these findings were not significantly different from those in patients with poor outcomes. The percentage of patients with LBP alone was significantly lower and the percentage of patients with LBP plus referred inguinal or leg pain was significantly higher in the group with good surgical outcome compared with patients in the group with poor surgical outcome (p <0.05). Conclusions: Worsening of pain on extension may be a symptom of DLBP. Surgical outcomes were superior in patients with both LBP and either referred inguinal or leg pain compared with those having LBP alone.

More than 6 Months of Teriparatide Treatment Was More Effective for Bone Union than Shorter Treatment Following Lumbar Posterolateral Fusion Surgery

Seiji Ohtori,Sumihisa Orita,Kazuyo Yamauchi,Yawara Eguchi,Nobuyasu Ochiai,Kazuki Kuniyoshi,Yasuchika Aoki,Junichi Nakamura,Masayuki Miyagi,Miyako Suzuki,Gou Kubota,Kazuhide Inage,Takeshi Sainoh,Jun Sa 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.4

Study Design: Retrospective case series. Purpose: To examine the most effective duration of teriparatide use for spinal fusion in women with postmenopausal osteoporosis. Overview of Literature: We reported that daily subcutaneous injection of teriparatide (parathyroid hormone) significantly improved bone union after instrumented lumbar posterolateral fusion (PLF) in women with postmenopausal osteoporosis when compared with oral administration of bisphosphonate. However, the most effective duration of teriparatide use for spinal fusion has not been explored. Methods: Forty-five women with osteoporosis diagnosed with degenerative spondylolisthesis from one of the three treatment groups were evaluated based on: short-duration treatment (average, 5.5 months; n=15; daily subcutaneous injection of 20 μg teriparatide), long-duration treatment (average, 13.0 months; n=15; daily subcutaneous injection of 20 μg teriparatide), and bisphosphonate treatment (average, 13.0 months; n=15; weekly oral administration of 17.5 mg risedronate). All patients underwent PLF with a local bone graft. Fusion rate and duration of bone union were evaluated 1.5 years after surgery. Results: Bone union rate and average duration for bone union were 92% and 7.5 months in the long-duration treatment group, 80% and 8.5 months in the short-duration treatment group, and 70% and 10.0 months in the bisphosphonate treatment group, respectively. Results of bone union rate and average duration for bone union in the teriparatide treatment groups were significantly superior to those in the bisphosphonate treatment group (p <0.05); whereas, significantly superior results were observed in long-duration treatment group when compared with short-duration treatment group (p <0.05). Conclusions: Daily injection of teriparatide for bone union was more effective than oral administration of bisphosphonate. Furthermore, a longer period of teriparatide treatment for bone union was more effective than a shorter period of same treatment.

Progressive Change in Joint Degeneration in Patients with Knee or Hip Osteoarthritis Treated with Fentanyl in a Randomized Trial

Tatsuya Fujii,Seiji Ohtori,Koshi Takana,Sumihisa Orita,Gen Inoue,Nobuyasu Ochiai,Kazuki Kuniyoshi,Yasuchika Aoki,Tetsuhiro Ishikawa,Masayuki Miyagi,Hiroto Kamoda,Miyako Suzuki,Yoshihiro Sakuma,Gou Kub 연세대학교의과대학 2014 Yonsei medical journal Vol.55 No.5

Purpose: Opioids improve pain from knee and hip osteoarthritis (OA) and decreasethe functional impairment of patients. However, there is a possibility that opioids induce analgesia and suppress the physiological pain of OA in patients, thereby inducing the progression of OA changes in these patients. The purpose of the current study was to investigate the possibility of progressive changes in OA among patients using opioids. Materials and Methods: Two hundred knee or hip OA patients were evaluated in the current prospective, randomized, active-controlledstudy. Patients were randomized 1:1:1 into three parallel treatment groups: loxoprofen, tramadol/acetaminophen, and transdermal fentanyl groups. Medicationwas administered for 12 weeks. Pain scores and progressive OA changes on X-ray films were evaluated. Results: Overall, pain relief was obtained by all three groups. Most patients did not show progressive OA changes; however, 3 patients in the transdermal fentanyl group showed progressive OA changes during the 12 weeks of treatment. These 3 patients used significantly higher doses than others in the transdermal fentanyl group. Additionally, the average pain score for these 3 patientswas significantly lower than the average pain score for the other patients in the transdermal fentanyl group. Conclusion: Fentanyl may induce progressive changes in knee or hip OA during a relatively short period, compared with oral Non-Steroidal Anti-Inflammatory Drugs or tramadol.

Efficacy of Direct Injection of Etanercept into Knee Joints for Pain in Moderate and Severe Knee Osteoarthritis

Seiji Ohtori,Sumihisa Orita,Kazuyo Yamauchi,Yawara Eguchi,Nobuyasu Ochiai,Shunji Kishida,Kazuki Kuniyoshi,Yasuchika Aoki,Junichi Nakamura,Tetsuhiro Ishikawa,Masayuki Miyagi,Hiroto Kamoda,Miyako Suzuki 연세대학교의과대학 2015 Yonsei medical journal Vol.56 No.5

Purpose: Osteoarthritic (OA) pain is largely considered to be inflammatory pain. However, during the last stage of knee OA, sensorynerve fibers in the knee are shown to be significantly damaged when the subchondral bone junction is destroyed, and this can induce neuropathic pain. Several authors have reported that tumor necrosis factor-α (TNFα) in a knee joint plays a crucial role in pain modulation. The purpose of the current study was to evaluate the efficacy of etanercept, a TNFα inhibitor, for pain in knee OA. Materials and Methods: Thirty-nine patients with knee OA and a 2–4 Kellgren-Lawrence grading were evaluated in this prospectivestudy. Patients were divided into two groups; hyaluronic acid (HA) and etanercept injection. All patients received a single injectioninto the knee. Pain scores were evaluated before and 4 weeks after injection using a visual analogue scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and they were compared between the groups. Results: Before injection, VAS and WOMAC scores were not significantly different between the groups (p>0.05). Significant pain relief was found in the etanercept group at 1 and 2 weeks by VAS, and at 4 weeks by WOMAC score, compared with the HA group (p<0.05). No adverse events were observed in either group. Conclusion: Direct injection of etanercept into OA knee joints was an effective treatment for pain in moderate and severe OA patients. Furthermore, this finding suggests that TNFα is one factor that induces OA pain.

Mini-Open Anterior Retroperitoneal Lumbar Interbody Fusion: Oblique Lateral Interbody Fusion for Lumbar Spinal Degeneration Disease

Seiji Ohtori,Sumihisa Orita,Kazuyo Yamauchi,Yawara Eguchi,Nobuyasu Ochiai,Shunji Kishida,Kazuki Kuniyoshi,Yasuchika Aoki,Junichi Nakamura,Tetsuhiro Ishikawa,Masayuki Miyagi,Hiroto Kamoda,Miyako Suzuki 연세대학교의과대학 2015 Yonsei medical journal Vol.56 No.4

Purpose: Surgery for lumbar spinal degeneration disease is widely performed. While posterior decompression and fusion are popular, anterior lumbar interbody fusion (ALIF) is also used for treatment. Extreme lateral interbody fusion (XLIF) is commonly used for noninvasive ALIF; however, several complications, such as spinal nerve and psoas muscle injury, have been reported. In the current study, we examined the clinical efficacy and complications of oblique lateral interbody fusion (OLIF) for lumbar spinal degeneration disease. Materials and Methods: Thirty-five patients with degenerated spondylolisthesis, discogenic pain, and kyphoscoliosiswere examined. All patients underwent OLIF surgery (using a cage and bone graft from the iliac crest) with or without posterior decompression, without real-time electromyography monitoring. Posterior screws were used in all patients. Visualanalog scale (VAS) score and Oswestry Disability Index (ODI) were evaluated before and 6 months after surgery. Surgical complications were also evaluated. Results:Pain scores significantly improved after surgery, compared to those before surgery (p<0.05). There was no patient who underwent revision surgery. There was no spinal nerve, major vessel, peritoneal, or urinary injury. Few patients showed symptoms from psoas invasion. Conclusion: OLIF surgery produced good surgical results without any major complication.

Does Discontinuing Teriparatide Treatment and Replacing It with Bisphosphonate Maintain the Volume of the Bone Fusion Mass after Lumbar Posterolateral Fusion in Women with Postmenopausal Osteoporosis?

Seiji Ohtori,Sumihisa Orita,Kazuyo Yamauchi,Yawara Eguchi,Yasuchika Aoki,Junichi Nakamura,Miyako Suzuki,Gou Kubota,Kazuhide Inage,Yasuhiro Shiga,Koki Abe,Kazuki Fujimoto,Hirohito Kanamoto,Masahiro Ino 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.2

Study Design: Retrospective case series. Purpose: The purpose of this study was to determine whether discontinuing teriparatide treatment and replacing it with bisphosphonate treatment maintains the volume of the fusion mass after posterolateral fusion (PLF) in women with postmenopausal osteoporosis. Overview of Literature: Clinical data support the efficacy of parathyroid hormone (PTH) for lumbar PLF. However, the use of PTH is limited to 2 years. Methods: We treated 19 women diagnosed with osteoporosis and degenerative spondylolisthesis with teriparatide (20 μg daily subcutaneously). All patients underwent one-level instrumented PLF. Teriparatide was used during 2 months prior to surgery and more than 8 months after surgery. After discontinuing teriparatide treatment, all patients used bisphosphonate (17.5 mg risedronate weekly, oral administration). Area of the fusion mass across the transverse processes at one segment was determined on an anteroposterior radiograph at 1, 2, and 3 years after surgery. Results: We followed 19 patients for 3 years. The average duration of teriparatide treatment was 11.5 months. The bone union rate was 95%. The average area of the bone fusion mass was not significantly different between the right and left sides at 1, 2, or 3 years after surgery (p >0.05). Conclusions: This study showed that replacing teriparatide treatment with bisphosphonate maintained the bone fusion mass volume after PLF in women with postmenopausal osteoporosis.

Efficacy of TachoSil, a Fibrin-Based Hemostat, for Anterior Lumbar Spine Surgery

Jo Watanabe,Seiji Ohtori,Sumihisa Orita,Kazuyo Yamauchi,Yawara Eguchi,Yasuchika Aoki,Junichi Nakamura,Miyako Suzuki,Kazuhide Inage,Jun Sato,Yasuhiro Shiga,Koki Abe,Kazuki Fujimoto,Hirohito Kanamoto,Ei 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.5

Study Design: Retrospective case series. Purpose: To examine the efficacy of TachoSil for vessel injury in 6 patients who underwent anterior lumbar fusion surgery (ALF). Overview of Literature: ALF for the lumbar spine has a high rate of success, although intraoperative concerns and iatrogenic complications are known, and injury of a major vessel is sometimes a complication. The efficacy of TachoSil, a fibrin-based hemostat, has been reported for several types of surgery; however, use of TachoSil for ALF surgery has not been described. Here, we report on the efficacy of TachoSil in 6 patients, who underwent ALF after vascular surgeons having difficulty in repairing vessels. Methods: Two man and 4 women with average age of 50.8±10.9 (mean±standard deviation) were diagnosed with a vertebral tumor (2 patients), L4 degenerative spondylolisthesis (2 patients), and L5 spondylolytic spondylolisthesis (2 patients) and underwent ALF. The blood vessels injured included the common iliac vein in 2 patients and a branch of a segmental artery from the aorta in 4 patients. We consulted a vascular surgeon to suture or repair the vessels during surgery, and although the vascular surgeon attempted to address the injuries, suturing or repair was not possible in these cases. For this reason, we used TachoSil to repair the injury in the vessels walls or to stop the bleeding. Results: Time to pressure hemostasis using TachoSil was 34±12 minutes, and total blood loss was 1,488±1,711 mL. Nevertheless, all vessel injuries were controlled by the use of TachoSil. Conclusions: We recommend the use of TachoSil for vessel injuries that vascular surgeons cannot suture or repair during ALF surgery.

Transdermal Fentanyl for Chronic Low Back Pain

Seiji Ohtori,Gen Inoue,Sumihisa Orita,Yawara Eguchi,Nobuyasu Ochiai,Shunji Kishida,Masashi Takaso,Yasuchika Aoki,Kazuki Kuniyoshi,Junichi Nakamura,Tetsuhiro Ishikawa,Gen Arai,Masayuki Miyagi,Hiroto Ka 연세대학교의과대학 2012 Yonsei medical journal Vol.53 No.4

Purpose: Chronic low back pain is a common clinical problem. As medication, non-steroidal anti-inflammatory drugs are generally used; however, they are sometimes non-effective. Recently, opioids have been used for the treatment of chronic low back pain, and since 2010, transdermal fentanyl has been used to treat chronic non-cancer pain in Japan. The purpose of the current study was to examine the efficacy of transdermal fentanyl in the treatment of chronic low back pain. Materials and Methods: This study included patients (n=62) that suffered from chronic low back pain and were non-responsive to non-steroidal anti-inflammatory drugs. Their conditions consisted of non-specific low back pain, multiple back operations, and specific low back pain awaiting surgery. Patients were given transdermal fentanyl for chronic low back pain. Scores of the visual analogue scale and the Oswestry Disability Index, as well as adverse events were evaluated before and after therapy. Results: Overall, visual analogue scale scores and Oswestry Disability Index scores improved significantly after treatment. Transdermal fentanyl (12.5 to 50 μg/h) was effective in reducing low back pain in 45 of 62 patients; however, it was not effective in 17 patients. Patients who experienced the most improvement were those with specific low back pain awaiting surgery. Adverse events were seen in 40% of patients (constipation, 29%; nausea, 24%; itching, 24%). Conclusion: Transdermal fentanyl significantly improved visual analog scale scores and Oswestry Disability Index scores in 73% of patients, especially those with specific low back pain awaiting surgery; however, it did not decrease pain in 27% of patients, including patients with non-specific low back pain or multiple back operations.