Takayuki Kitahara, Masatoshi Morimoto, Naoto Ono, Takafumi Ohshima, Yuji Nagao, Saori Soeda, Kosuke Sugiura, Hiroaki Manabe, Fumitake Tezuka, Hiroshi Kageyama, Junzo Fujitani, Kazuta Yamashita and Koichi Sairyo : Maximal facet tropism of 10.8° as a quantitative cutoff for predicting lumbar disk herniation in young elite athletes: a retrospective case-control study in Japan., Asian Spine Journal, 2026.
(要約)
Retrospective case-control study.To determine whether maximal facet tropism (FT) is an independent risk factor for lumbar disk herniation (LDH) in young athletes and establish a data-driven, quantitative cutoff value.The role of FT in LDH remains debated because previous studies have focused on level-specific prevalence without defining a clinically significant threshold for maximal asymmetry, particularly in athletes.Axial magnetic resonance images from L3 to S1 in 43 athletes were compared with LDH and 11 symptomatic nonherniated athletes. The primary variable was maximal FT, the single greatest asymmetry across the measured levels. Risk was assessed using multivariable logistic regression, and a cutoff was determined by receiver-operating characteristic (ROC) curve analysis.The LDH group exhibited significantly greater maximal FT (11.8°±5.9° vs. 7.6°±3.0°, p=0.028) and was confirmed to be an independent predictor of LDH (with odds ratio of 1.23 per increment of 1°; p=0.041). ROC curve analysis identified an optimal 10.8° cutoff (area under the ROC curve, 0.727), yielding 55.8% sensitivity and 90.9% specificity. Although severe FT (>10°) was most prevalent at L5/S1 in the LDH group (p=0.024), maximal FT values were not significantly different between the L4/5 and L5/S1 groups (p=0.353) in an analysis stratified by herniation level.Maximal FT is an independent risk factor for LDH in young athletes. The magnitude of maximal asymmetry in the lower lumbar spine, rather than its specific spinal level, appears to be the primary contributor to this risk, and an angle >10.8° serves as a preliminary threshold for identifying high-risk athletes.
Takayuki Kitahara, Takafumi Ohshima, Naoto Ono, Yuji Nagao, Saori Soeda, Kosuke Sugiura, Masatoshi Morimoto, Hiroaki Manabe, Fumitake Tezuka, Hiroshi Kageyama, Junzo Fujitani, Kazuta Yamashita and Koichi Sairyo : Transforaminal Full-Endoscopic Lumbar Foraminotomy Under Local Anesthesia for L5/S1 Adjacent Segment Foraminal Stenosis., Journal of visualized experiments : JoVE, 224, 2025.
(要約)
Foraminal stenosis in patients with L5/S1 adjacent segment disease (ASD) presents a significant clinical challenge, as conventional treatment often requires fusion extension surgery. This approach sacrifices spinal mobility and is associated with considerable surgical morbidity. This video article describes a motion-preserving surgical alternative, namely, transforaminal full-endoscopic foraminotomy performed under local anesthesia, detailing a step-by-step protocol to navigate the challenges of these revision cases. The technique utilizes a posterolateral corridor, avoiding prior surgical scarring. Key procedural steps include meticulous preoperative trajectory planning, foraminoplasty via resection of the superior articular process (SAP), and partial resection of the inferior articular process to fully expose the ligamentum flavum (LF). A specific "detach" technique is then demonstrated, involving undercutting the ventral rim of the S1 SAP to release the LF before its removal. Representative results demonstrate successful osseous decompression confirmed by postoperative computed tomography. The procedure resulted in immediate improvement in radicular pain and motor weakness, with the patient's visual analog scale score decreasing from 9/10 to 1/10 at the one-month follow-up. This minimally invasive technique provides effective neural decompression and facilitates rapid recovery, offering a valuable alternative to more extensive surgery for this challenging patient population.
Ryota Mio, Fumiaki Makiyama, Hiroshi Kageyama, Saori Soeda, Yuij Nagao, Naoto Ono, Masatoshi Morimoto, Hiroaki Manabe, Fumitake Tezuka, Kazuta Yamashita and Koichi Sairyo : Impact of Extended Endoscopic Lumbar Foraminotomy on Postoperative Surgical Outcomes: Is Greater Decompression Beneficial?, International Journal of Spine Surgery, 19, 4, 418-425, 2025.
(要約)
The transforaminal (TF) approach in full endoscopic spine surgery (FESS) is the least invasive spinal surgery, as it can be performed under local anesthesia with only an 8-mm skin incision. Transforaminal FESS-based foraminotomy was first performed in the early 2000s for the decompression of foraminal stenosis. The technique has improved year by year over the past 2 decades. In our hospital, full endoscopic lumbar foraminotomy (FELF) has been performed since 2015. Since our development of the FESS undercutting laminectomy procedures in 2019, the size of the decompressed area achieved by FELF has increased.To estimate the technical alteration of FELF over time by comparing the pre- and postoperative osseous foraminal areas (FAs) between traditional and advanced FELF techniques.Fifty-two cases were retrospectively reviewed. In the early phase of FELF before 2019, partial or total resection of the superior articular process (SAP) was performed. Twenty-six of the patients were treated using the traditional FELF procedure (SAP-ectomy group). The remaining 26 underwent advanced FELF procedures, including SAP-ectomy, undercutting laminectomy, and removal of the ligamentum flavum (advanced FELF group). Clinical outcomes were assessed using the modified MacNab score. Pre- and postoperative osseous FAs were measured on sagittal computed tomography, and data were compared between the SAP-ectomy and advanced FELF groups. Paired and unpaired t tests were used for statistical analysis.By the modified MacNab score, the excellent/good rate was 82.6% in the SAP-ectomy group and 95.5% in the advanced FELF group. The improvement was greater in advanced FELF but not significantly. FA prior to surgery was 87.5 ± 27.0 mm2 in the SAP-ectomy group and 95.7 ± 34.3 mm2 in the advanced FELF group, with postoperative increases to 151.4 ± 45.5 mm2 and 195.3 ± 39.1 mm2, respectively (P < 0.05). FA increased by 63.9% and 99.6% in the SAP-ectomy and advanced FELF groups, respectively.Full endoscopic foraminotomy techniques have evolved over time. The recently developed advanced FELF technique appears to safely and effectively achieve better clinical outcomes by significantly enlarging FA.The advanced FELF technique contributes to improved decompression of the exiting nerve root.
Yutaka Kinoshita, Toshinori Sakai, Kosuke Sugiura, Takahisa Kurosaki, Jiro Kobayashi, Saori Soeda, Yasuaki Tamaki, Masatoshi Morimoto, Hiroaki Manabe, Fumitake Tezuka, Kazuta Yamashita and Koichi Sairyo : Can MRI Replace CT in the Diagnosis and Staging of Lumbar Spondylolysis in Pediatric Patients? A Validation Study Using MR Bone Imaging, Journal of Pediatric Orthopedics, 46, 1, e56-e60, 2025.
(要約)
Magnetic resonance (MR) bone imaging may reduce radiation exposure compared with computed tomography (CT) in staging lumbar spondylolysis. This study aimed to validate the consistency between MR bone imaging and CT. We retrospectively investigated short tau inversion recovery (STIR), MR bone imaging, and CT scans of patients diagnosed with lumbar spondylolysis who underwent MRI and CT scans within 2 weeks between November 2021 and March 2023.We identified 190 fractures in 968 pars interarticularis of 105 patients. MR bone imaging was based on Siemens 3 Tesla T1-weighted volumetric interpolated breath-hold imaging (T1 VIBE). The CT-based staging and T1 VIBE-based staging were matched [incomplete fracture, complete fracture, gap of 2 mm (gap)]. For fracture detection with CT as a reference, the respective sensitivity, specificity, and accuracy were 94%, 99%, and 99% for incomplete fracture, 74%, 100%, and 98% for complete fracture, 81%, 99%, and 99% for gap, and 97%, 100%, and 100% for any fracture. When we assessed 62 pars with complete fracture or a gap, the rates were 91%, 100%, and 99%, respectively. In staging 190 fractures with CT as a reference, the respective sensitivity, specificity, and accuracy were 94%, 91%, and 93% for incomplete fracture, 74%, 96%, and 91% for complete fracture, 81%, 96%, and 95% for gap, and 97%, 100%, and 97% for any fracture. The respective values were 91%, 98%, and 96% for complete fracture combined with gap. Of 153 pedicles with high signal change on STIR, 10 showed no fracture line, 110 showed incomplete fracture lines, 30 showed complete fracture lines, and 3 showed a gap on T1 VIBE, compared with 5, 109, 39, and 0, respectively, on CT. The T1 VIBE sequence is highly accurate, although it has some limitations in fracture detection. T1 VIBE can be used clinically in conjunction with STIR and may replace CT in determining the treatment strategy for lumbar spondylolysis, resulting in reduced medical radiation exposure to pediatric patients. Level III diagnostic study.
Saori Soeda, Masatoshi Morimoto, Kosuke Sugiura, Kousaku Higashino, Shunsuke Tamaki, Keisuke Nishidono, Kiyoshi Yagi, Kazuya Kishima, Hiroaki Manabe and Koichi Sairyo : Lumbar apophyseal ring fracture: Prevalence and relationship with spina bifida occulta., Journal of Orthopaedic Science, 31, 1, 76-80, 2025.
(要約)
To investigate the prevalence of apophyseal ring fracture and its association with spina bifida occulta (SBO).A total of 973 patients (mean age 62 years [range 21-90]) with abdominal and pelvic computed tomography scans available were retrospectively evaluated. The prevalence of apophyseal ring fracture and of SBO and the association between these two entities were evaluated.The prevalence of apophyseal ring fracture was 3.8 % (n = 22) in men and 2.8 % (n = 11) in women; the difference was not statistically significant (p = 0.53). The incidence was highest at L5 in both men (58.3 %, n = 14) and women (38.5 %, n = 5). SBO was found in 92 patients (9.5 %), who comprised 75 men (12.9 %) and 17 women (4.4 %). The prevalence of SBO was 2.95-fold higher in men than in women (p < 0.0001). Apophyseal ring fracture was 2.6 times more frequent in patients who had SBO than in those who did not (7.6 % vs 3.0 %, p = 0.019).This study identified the lower lumbar levels as the anatomical locations where apophyseal ring fracture was more likely to occur, particularly involving the anterior portion of the cephalad endplate at L3 and L4 and the posterior portion of the cephalad endplate at S1. This finding will be helpful for understanding the site of origin of apophyseal ring fractures, which can be easily overlooked. In addition, apophyseal ring fractures were more frequent in the presence of SBO, which may contribute to understanding their etiology.
(キーワード)
Humans / Male / Female / Middle Aged / Aged / Retrospective Studies / Adult / Prevalence / Aged, 80 and over / Spina Bifida Occulta / Lumbar Vertebrae / Spinal Fractures / Young Adult / Tomography, X-Ray Computed
Yutaro Kanda, Fumiaki Makiyama, Ryota Mio, Kozaburo Mizutani, Masashi Kumon, Saori Soeda, Masatoshi Morimoto, Fumitake Tezuka, Kazuta Yamashita and Koichi Sairyo : Short-term Clinical and Radiographic Outcomes of Transforaminal Full-endoscopic Pars Crisscross Decompression of the Exiting Nerve Root under Local Anesthesia in Adult Isthmic Spondylolisthesis., Neurologia Medico-Chirurgica, 65, 6, 271-277, 2025.
(要約)
In adult isthmic spondylolysis/spondylolisthesis, a fibrocartilaginous mass, ragged edge, and decrease in disk height cause radiculopathy with intervertebral foraminal stenosis. There are few reports on the outcomes of full-endoscopic spine surgery for isthmic spondylolisthesis because of difficulty in the ragged edge resection. This study evaluated the short-term outcomes of our original full-endoscopic spine surgery technique in patients with isthmic spondylolisthesis with a focus on the "pars crisscross." An important landmark, the pars crisscross consist of the superior articular process at S1, floating lamina, inferior articular process at L4, and pars ragged edge. The exiting nerve root can only be decompressed by complete resection of the ragged edge after confirmation of the pars crisscross. This case series includes 6 patients (mean age 63.2 ± 14.3 years) who underwent full-endoscopic spine surgery under local anesthesia for radiculopathy. The leg pain improved immediately after surgery in all patients and the mean visual analog scale score improved from 8.2 ± 1.3 preoperatively to 1.2 ± 1.1 at 2 weeks postoperatively. The neuroforaminal area at the inlet and center expanded dramatically from 184 ± 41 mm2 and 192 ± 45 mm2, respectively, before surgery to 340 ± 55 mm2 and 338 ± 80 mm2 postoperatively. No patient experienced a recurrence of leg pain, aggravation of low back pain, or spinal instability during the 3 months after surgery. full-endoscopic spine surgery pars crisscross decompression had excellent short-term clinical and radiographic outcomes. Patients who are unsuitable for general anesthesia and instrumentation surgery could be candidates for this procedure.
Yutaro Kanda, Kozaburo Mizutani, Masashi Kumon, Saori Soeda, Kosuke Sugiura, Masatoshi Morimoto, Fumitake Tezuka, Kazuta Yamashita and Koichi Sairyo : Pitfalls in the Diagnosis and Treatment of Low Back Pain in an Elite Para-athlete Successfully Treated by Transforaminal Full-endoscopic Discectomy with Thermal Annuloplasty: A Case Reports., NMC Case Report Journal, 12, 7-13, 2025.
(要約)
We report a rare case of an elite para-athlete with lumbar disk herniation whose pain generator was difficult to diagnose and treat. A 28-year-old woman with paraplegia below the T10 level felt pain in her low back and left leg during a match. Magnetic resonance imaging revealed a lateral lumbar disk herniation and a high-intensity zone on the left side at the L5-L6 level. Because the pain disappeared following L5 selective nerve block, we performed transforaminal full-endoscopic discectomy alone. Despite the disappearance of leg pain after surgery, her low back pain persisted. We performed thermal annuloplasty because reproducible pain and subsequent temporary pain relief by discography and discoblock after the initial surgery indicated discogenic pain. Her suffering from back pain gradually reduced. She returned to competition 2 months after the second surgery without intensive rehabilitation due to difficulty in performing core exercises for abdominal muscles. During the return match, she experienced a relapse of pain in the low back and left leg, which was caused by a recurrence of disk herniation. We performed a full-endoscopic discectomy with thermal annuloplasty again. Her clinical symptoms were immediately relieved. We enhanced her thoracic spine flexibility to prevent subsequent recurrence. Finally, she returned to international competition 2 months after the third surgery. Close attention to para-athletes is required to achieve an accurate diagnosis of pain generators and prevent recurrence due to their distinctive disorders. Thermal annuloplasty and rehabilitating thoracic movement can be an excellent option for para-athletes with discogenic low back pain.
Saori Soeda, Nori Sato, Kosuke Sugiura, Hiroaki Manabe, Masatoshi Morimoto, Fumitake Tezuka, Kazuta Yamashita, Junzo Fujitani and Koichi Sairyo : How should we intervene to increase the number of female spine surgeons? A preliminary survey of trainees in Japan from medical school through spine fellowship., The Journal of Medical Investigation : JMI, 72, 3.4, 425-429, 2025.
(要約)
Women account for 23.6% of physicians in Japan yet account for only 5% of orthopedic surgeons and <1% of board-certified spine surgeons. We identified points along the training pathway where women perceive barriers to pursuing spine surgery.In this sequential explanatory mixed-methods study, we surveyed all 5th- and 6th-year medical students at our institution and postgraduate year-1-2 residents and received responses from 62 trainees (29 women, 33 men). Counts, percentages, and χ2 or Fisher exact tests were used to compare the groups. We thematically analyzed the semi-structured e-mail interviews conducted with 10 female orthopedic trainees (4 residents, 1 non-spine surgeon, and 5 spine fellows).Interest in orthopedics was reported by 45% of women and 64% of men (p=0.22);within that subgroup interest in spine surgery was similar (31% vs. 33%;p=1.00). From the interviews, four categories of barriers to choosing spine surgery as a subspecialty emerged:(1) physical limitations, (2) radiation exposure, (3) demanding working hours/on‑call, and (4) a gender‑imbalanced environment.Many early-career women already express interest in orthopedics. However, translating that interest into careers as spine surgeons will require sustained mentorship plus the adoption of assistive technologies, ergonomic instruments, and team-based shift schedules-interventions that could benefit the entire surgical workforce. J. Med. Invest. 72 : 425-429, August, 2025.
(キーワード)
Humans / Japan / Female / Male / Surveys and Questionnaires / Spine / Fellowships and Scholarships / Orthopedics / Students, Medical / Career Choice / Physicians, Women / Adult / Orthopedic Surgeons
Koichi Sairyo, Yutaro Kanda, Kozaburo Mizutani, Masashi Kumon, Saori Soeda, Fumiaki Makiyama, Ryota Mio, Masatoshi Morimoto, Shunsuke Tamaki, Keisuke Nishidono, Kosuke Sugiura, Makoto Takeuchi, Hiroaki Manabe, Fumitake Tezuka, Kazuta Yamashita, Hiroshi Kageyama and Junzo Fujitani : Transforaminal full-endoscopic decompression under local anesthesia for foraminal stenosis due to stable L5 isthmic spondylolisthesis, a technical note and review:Pars crisscross decompression., The Journal of Medical Investigation : JMI, 71, 3.4, 191-196, 2024.
(要約)
Foraminal stenosis is one of the types of lumbar spinal stenosis. The pathology can be treated minimally invasively by full-endoscopic spine surgery (FESS). The final challenge in transforaminal FESS is foraminal stenosis in patients with stable isthmic spondylolisthesis at L5. This article provides a step-by-step explanation of how to achieve complete decompression. A cannula of 8 mm in diameter is docked at the base of the superior articular process of the sacrum. The pars crisscross that consists of the superior articular process at S1, the floating lamina, the inferior articular process at L4, and the pars ragged edge is then clearly seen endoscopically. Visualization of the pars crisscross is key to successful decompression. Starting with the superior articular process at S1, followed by partial removal of the floating lamina. Next, the tip of the inferior articular process at L4 is removed. The pars ragged edge is then carefully shaved. Finally, decompression of the exiting nerve root at L5 is confirmed. This report provides the first step-by step description of full-endoscopic decompression of foraminal stenosis under local anesthesia in patients with stable L5 isthmic spondylolisthesis, which we have named "full-endoscopic pars crisscross decompression". J. Med. Invest. 71 : 191-196, August, 2024.