Short-segment spinal fusion for chronic low back pain with bone marrow edema adjacent to the vertebral endplate in adult spinal deformity.

PURPOSE: Corrective long spinal fusion is a widely accepted surgical method for patients with adult spinal deformities. However, instrumented long fusion is associated with a significant risk of complications. Therefore, we aimed to assess the success of short-segment spinal fusion, particularly for bone marrow edema (BME) adjacent to the vertebral endplate, in patients with low back pain (LBP) and spinal deformity. METHODS: A prospective study was performed at multiple hospitals wherein we monitored patients with spinal deformities and accompanying LBP. Patients aged ≥ 50 years with a minimum LBP severity score of 40 mm on the visual analog scale (VAS) were included in the study. We also included patients with lumbar BME on magnetic resonance imaging. Short spinal fusion was performed on segments with BME. Clinical evaluations of LBP on VAS and Oswestry Disability Index (ODI), and radiological parameters for sagittal vertical axis (SVA), pelvic incidence (PI), lumbar lordosis (LL) and pelvic tilt (PT) were carried out. RESULTS: Overall, 35 patients (22 men and 13 women), with a mean age of 66.7 years and a mean follow-up period of 32 months, were included in the study. The mean VAS and ODI scores were 72.4 mm and 49.0% before surgery and 25.5 mm and 29.9% at the final follow-up, respectively; these parameters significantly improved after surgery. The SVA, PI-LL, and PT scores were 70.1 mm, 20.9°, and 22.8° before surgery and 85.4 mm, 13.8°, and 22.7° at the final follow-up, respectively. The spinal alignment parameters did not change significantly after surgery. CONCLUSIONS: Short-segment spinal fusion is effective for treating LBP and spinal deformity with BME adjacent to the vertebral endplate without spinal correction.

Development of a novel animal model of lumbar vertebral endplate lesion by intervertebral disk injection of monosodium iodoacetate in rats.

PURPOSE: Vertebral endplate lesions (EPLs) caused by severe disk degeneration are associated with low back pain. However, its pathophysiology remains unclear. In this study, we aimed to develop a vertebral EPL rat model mimicking severe intervertebral disk (IVD) degeneration by injecting monosodium iodoacetate (MIA) into the IVDs and evaluating it by assessing pain-related behavior, micro-computed tomography (CT) findings, and histological changes. METHODS: MIA was injected into the L4-5 and L5-6 IVDs of Sprague-Dawley rats. Their behavior was examined by measuring the total distance traveled and the total number of rearing in an open square arena. Bone alterations and volume around the vertebral endplate were assessed using micro-CT. Safranin-O staining, immunohistochemistry, and tartrate-resistant acid phosphatase (TRAP) staining were performed for histological assessment. RESULTS: The total distance and number of rearing times in the open field were significantly reduced in a time-dependent manner. Micro-CT revealed intervertebral osteophytes and irregularities in the endplates at 12 weeks. The bone volume/tissue volume (BV/TV) around the endplates significantly increased from 6 weeks onward. Safranin-O staining revealed severe degeneration of IVDs and endplate disorders in a dose- and time-dependent manner. Calcitonin gene-related peptide-positive nerve fibers significantly increased from 6 weeks onward. However, the number of osteoclasts decreased over time. CONCLUSION: Our rat EPL model showed progressive morphological vertebral endplate changes in a time- and concentration-dependent manner, similar to the degenerative changes in human IVDs. This model can be used as an animal model of severe IVD degeneration to better understand the pathophysiology of EPL.

Development of a novel approach for restoration of the meniscus using silk-elastin in a rabbit meniscus injury model.

BACKGROUND: Limited healing potential of the meniscus remains a burden for the successful repair of meniscus injuries in the orthopaedic fields. Silk-elastin (SE) is a novel recombinant protein with favorable properties for wound healing. This proof-of-concept study aimed to investigate the therapeutic effect of silk-elastin in a rabbit meniscal defect model. METHODS: A migration assay using rabbit meniscus and synovial cells with various concentrations of SE in a culture medium was conducted to investigate the mechanism of meniscal healing by SE. Additionally, cylindrical defects with a 1.5 mm diameter were created at the anterior horn of the medial meniscus of rabbits. The animals were divided into three groups: 1) the Blank group; defect only, 2) the Col I group; implantation of type I atelocollagen sponge, and 3) the SE group; implantation of SE (150 mg/ml) sponge. Whole medial menisci were harvested at 4, 8, 12, and 24 weeks after surgery. Histological analyses including immunohistochemical staining were performed to assess meniscal healing. RESULTS: In vitro study, Migration assay demonstrated a significantly higher number of migrated cells only in synovial cells. Especially, the SE concentration of 10 µg/mL demonstrated the highest number of migrated cells compared with other concentrations. In vivo study, the SE group exhibited significantly higher Ishida scores than other groups at all time points. Furthermore, the SE group showed higher synovial coverage scores than the Col I group at 4 and 8 weeks. Immunohistochemical staining demonstrated higher type II collagen staining in the SE group compared to other groups at 12 weeks. Implanted SE was efficiently replaced by safranin-O staining positive tissue within 8 weeks. CONCLUSIONS: SE could effectively repair a meniscal defect by inducing coverage of synovial cells. SE has the potential to be a useful material for meniscal repair.

Vertebral osteomyelitis due to Mycobacterium abscessus subsp. massiliense with paravertebral abscess: A case report and review.

The incidence of vertebral osteomyelitis (VO) caused by non-tuberculosis mycobacteria (NTM) without immunocompetence is extremely rare. Herein, we reported on a case of VO caused by NTM. A 38-year-old man was admitted to our hospital with persisting low back and leg pain which had lasted for a year. Before coming to our hospital, the patient was treated with antibiotics and iliopsoas muscle drainage. The biopsy confirmed the presence of a NTM, Mycobacterium abscessus subsp. massiliense. Several tests were conducted which showed the infection had progressively increased, such as vertebral endplate destruction on plain radiography, computed tomography scan, and epidural and paraspinal muscle abscesses on magnetic resonance imaging. The patient underwent radical debridement, anterior intervertebral fusion with bone graft, and posterior instrumentation with antibiotic administration. A year later, the patient's low back and leg pain was relieved without any analgetic. VO due to NTM is rare but can be treated with multimodal therapy.

Balancing ability of patients with lumbar spinal canal stenosis.

PURPOSE: To determine the relationship between postural sway and the severity of lumbar spinal canal stenosis as well as the effect on postoperative improvement. METHODS: Stabilometry was performed before and 6 months after surgery in 52 patients (29 men and 23 women; mean age, 74.1 ± 7.8 years) who underwent decompression surgery for lumbar spinal canal stenosis. The environmental area (EA; the area surrounding the circumference of the stabilogram) and locus length per EA (L/EA) were evaluated. The patients were divided into moderate (n = 22) and severe (n = 30) groups according to the severity of canal stenosis. Patient characteristics and parameters were compared between the groups before and after surgery, including the visual analog scale (VAS) score for leg pain, Oswestry Disability Index (ODI), EA, and L/EA. In addition, factors affecting EA and L/EA were evaluated using multiple regression analysis. RESULTS: Age (p = 0.031), preoperative EA (p < 0.001), preoperative L/EA (p = 0.032), and sagittal vertical axis (p = 0.033) were significantly different between groups. The VAS score and ODI significantly improved postoperatively in both groups (p < 0.001). The EA significantly improved postoperatively only in the severe group (p < 0.001), whereas the L/EA did not significantly improve in either group. Multiple regression analysis showed that only the severity of canal stenosis was significantly associated with preoperative EA (p = 0.030), whereas age (p = 0.040) and severity of canal stenosis (p = 0.030) were significantly associated with preoperative L/EA. Diabetes was significantly associated with postoperative EA (p = 0.046) and L/EA (p = 0.030). CONCLUSION: The severity of canal stenosis affected abnormal postural sway, which improved after decompression surgery.

Deficiency of MicroRNA-23-27-24 Clusters Exhibits the Impairment of Myelination in the Central Nervous System.

Several microRNAs (miRNAs), including miR-23 and miR-27a have been reportedly involved in regulating myelination in the central nervous system. Although miR-23 and miR-27a form clusters in vivo and the clustered miRNAs are known to perform complementary functions, the role of these miRNA clusters in myelination has not been studied. To investigate the role of miR-23-27-24 clusters in myelination, we generated miR-23-27-24 cluster knockout mice and evaluated myelination in the brain and spinal cord. Our results showed that 10-week-old knockout mice had reduced motor function in the hanging wire test compared to the wild-type mice. At 4 weeks, 10 weeks, and 12 months of age, knockout mice showed reduced myelination compared to wild-type mice. The expression levels of myelin basic protein and myelin proteolipid protein were also significantly lower in the knockout mice compared to the wild-type mice. Although differentiation of oligodendrocyte progenitor cells to oligodendrocytes was not inhibited in the knockout mice, the percentage of oligodendrocytes expressing myelin basic protein was significantly lower in 4-week-old knockout mice than that in wild-type mice. Proteome analysis and western blotting showed increased expression of leucine-zipper-like transcription regulator 1 (LZTR1) and decreased expression of R-RAS and phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) in the knockout mice. In summary, loss of miR-23-27-24 clusters reduces myelination and compromises motor functions in mice. Further, LZTR1, which regulates R-RAS upstream of the ERK1/2 pathway, a signal that promotes myelination, has been identified as a novel target of the miR-23-27-24 cluster in this study.

Intradiscal Condoliase Injection Therapy for Recurrent Lumbar Disc Herniation: Case Series and Literature Review.

Background and objectives: Although chemonucleolysis with condoliase for lumbar disc herniation (LDH) has become common, few reports have described its application in the treatment of recurrent LDH. Therefore, this study aimed to evaluate the safety and efficacy of condoliase treatment in six patients with recurrent LDH and review the available literature on condoliase treatment for LDH. Materials and Methods: Six patients (four men and two women; mean age, 64.7 years) with recurrent LDH who were treated with condoliase at our hospital between 2019 and 2022 were included. The clinical records and images of the patients were retrospectively evaluated. In addition, the available English literature on condoliase treatment for LDH was retrieved and reviewed. Results: Among the six patients included in the study, three showed >50% improvement in leg pain after treatment, which is a lower efficacy rate than that in previous reports. In addition, two patients required surgery after treatment, which is a higher rate than that in previous reports. The mean intervertebral disc height significantly decreased from 8.4 mm before treatment to 6.9 mm after treatment, consistent with the results of previous studies. None of the cases showed Modic type I changes on magnetic resonance imaging. Conclusions: Although the efficacy of condoliase treatment for recurrent LDH may be lower than that for primary LDH, this treatment was found to be safe and applicable for recurrent LDH.

Vertebral osteomyelitis caused by Mycobacteroides abscessus subsp. abscessus resulting in spinal cord injury due to vertebral body fractures.

Nontuberculous mycobacteria (NTM) rarely cause vertebral osteomyelitis; however, the clinical characteristics of vertebral osteomyelitis caused by NTM are poorly understood due to its rarity. A 74-year-old man with lung cancer was treated with prednisolone for immune checkpoint inhibitor-associated immune-related adverse events. He had been experiencing mild back pain without febrile episodes for five months, and was admitted to the hospital for worsening back pain and progressive paraplegia. Magnetic resonance imaging showed spinal cord compression at T4-5 due to fractures of the T5 and T7 vertebral bodies. The culture of a sample of pus from the T7 vertebral body obtained at the time of spinal fusion surgery yielded the Mycobacteroides abscessus (M. abscessus) complex. The patient was diagnosed with vertebral osteomyelitis caused by M. abscessus complex and treated with clarithromycin, amikacin, and imipenem; clarithromycin was later replaced by sitafloxacin because of inducible macrolide resistance. However, his neurologic deficits were irreversible, and he died due to a deteriorating general condition. The strain was identified up to subspecies level as M. abscessus subsp. abscessus by hsp65 and rpoB sequencing and nucleic acid chromatography. Although vertebral osteomyelitis due to NTM is rare, delayed diagnosis can lead to serious complications or poor outcomes. A prolonged clinical course, less frequent fever, vertebral destruction or spinal deformity, neurological deficits, or immunosuppressed conditions might be suggestive of NTM vertebral osteomyelitis.

Development of a rat model with lumbar vertebral endplate lesion.

PURPOSE: Vertebral endplate lesion (EPL) caused by severe disc degeneration is associated with low back pain. However, there is no suitable animal model to elucidate the pathophysiology of EPL. This study aimed to develop a rat model of EPL and evaluate rat behavior and imaging and histological findings. METHODS: The L4-5 intervertebral discs of Sprague-Dawley rats were transperitoneally removed, except for the outer annulus fibrosus and cartilage endplate, in the EPL group. The L4-5 discs were not removed and simply exposed in the sham group. Changes around the vertebral endplate on magnetic resonance imaging (MRI) and computed tomography (CT) were evaluated. Additionally, pain-related behavioral and histological assessments were performed. RESULTS: In the EPL group, a low-signal area around the vertebral endplate was observed on T1-weighted and T2-weighted fat-saturated MRI at 8 weeks or later after surgery. In the same group, CT showed osteosclerosis around the vertebral endplate at 12 weeks after surgery. The sham group did not show abnormal imaging features on the MRI and CT. Behavioral evaluation showed that the EPL group had a significantly longer grooming time than the sham group. Conversely, the 12-week postoperative locomotion time and the 1- and 12-week postoperative standing times were significantly shorter in the EPL group than in the sham group. Histological evaluation showed a high degree of vertebral endplate degeneration and an increased number of osteoclasts and proportion of nerve fibers expressing calcitonin gene-related peptide in the EPL group compared to those in the sham group. CONCLUSION: Our rat EPL model showed pain-related behavioral patterns and an increased expression of pain-related neuropeptide. This model could contribute to the study of the pathophysiology of EPL and will help in the treatment of low back pain in the future.

Comparison of the electrophysiological characteristics of tight filum terminale and tethered cord syndrome.

PURPOSE: This study aims to characterize tight filum terminale (TFT) in motor evoked potential (MEP) testing by comparing TFT patients with both tethered cord syndrome (TCS) patients and healthy subjects. METHODS: Fifty TFT patients, 18 TCS patients, and 35 healthy volunteers participated in this study. We recorded MEPs following transcranial magnetic stimulation from the bilateral abductor hallucis muscles as well as compound muscle action potentials and F-waves evoked by electrical stimulation of the tibial nerve from the bilateral abductor pollicis brevis muscles. The peripheral conduction time (PCT) was calculated from the latency of the compound action potential and F-wave. Furthermore, the central motor conduction time (CMCT) was calculated by subtracting PCT from MEP latency. RESULTS: TFT and TCS patients had a significantly longer MEP latency than healthy subjects. PCT in TFT patients was significantly longer than those in TCS patients or healthy subjects. Using the cutoff values for PCT, we were able to diagnose patients with TFT patients with a sensitivity of 72.0% and a specificity of 91.4%. CONCLUSION: Prolonged PCT in the MEP test may be a useful indicator for TFT and suggests that MEP may be used as an adjunct diagnostic tool for TFT.

Prognostic factors for spontaneous spinal epidural hematoma: a multicenter case-control study.

BACKGROUND: To determine the optimal treatment for spontaneous spinal epidural hematoma (SSEH). The aim of this study was to identify factors associated with SSEH. METHODS: In 62 patients with SSEH, several patient-related parameters were analyzed as candidate factors associated with Frankel grade before treatment or at the last follow-up. These parameters were compared between patients with and without surgery. In addition, multivariate ordinal logistic regression analysis was used to identify factors significantly associated with Frankel's grade before treatment or at the last follow-up. RESULTS: There were significant differences in age, location of the hematoma, and Frankel grade before treatment and at the last follow-up between surgical and nonsurgical cases in all patients, but there were no significant differences in any of these parameters when comparing patients with pre-treatment Frankel grade C. The location of the hematoma was significantly associated with the severity of paralysis before treatment. In surgical cases, the time from onset to surgery and the location of the hematoma was significantly associated with the prognosis. When the time from onset to surgery was evaluated using the criteria of 12, 24, and 48 h, 24 and 48 h had a significant impact on the prognosis. In the analysis of nonsurgical cases, only the vertical size of the hematoma was significantly associated with prognosis. CONCLUSION: The time from onset to surgery and the location of the hematoma were prognostic factors in surgical cases, while the vertical size of the hematoma was a prognostic factor in nonsurgical cases.

Surgical outcomes of cervical myelopathy in patients with athetoid cerebral palsy.

PURPOSE: Surgical treatment for cervical myelopathy with athetoid cerebral palsy remains unestablished. Instrumented fusion is reported to have good clinical results; however, there are no data of decompression surgery for this pathology in recent years. This study aimed to assess the surgical outcomes of laminoplasty with or without posterior instrumented fusion for cervical myelopathy in patients with athetoid cerebral palsy. METHODS: A multi-centre surgical series of patients with cervical myelopathy and athetoid cerebral palsy were enrolled in this study. All patients showed symptoms and signs suggestive of cervical myelopathy and underwent laminoplasty with or without instrumented fusion. The Japanese Orthopaedic Association (JOA) score, Barthel index (BI), and changes in the C2-C7 sagittal Cobb angle in the lateral plain radiograph were analysed. RESULTS: There were 25 patients (16 men and 9 women; mean age, 54.4 ± 10.8 years) with cervical myelopathy and athetoid cerebral palsy who underwent surgical treatment. The mean follow-up period was 41.9 ± 35.6 months. Overall, the BI significantly improved after surgery, whereas the JOA score and C2-C7 angle did not improve postoperatively. The recovery rate of the JOA score in the laminoplasty group was significantly higher than that of the fusion group (P = 0.02). CONCLUSIONS: Cervical laminoplasty with or without instrumented fusion for treating cervical myelopathy due to athetoid cerebral palsy is effective in improving activities of daily living. Cervical laminoplasty may be an effective and less invasive surgical method for selective patients, especially for those with small involuntary movements and no remarkable cervical kyphosis nor instability.

Long-term outcome of targeted therapy for low back pain in elderly degenerative lumbar scoliosis.

PURPOSE: Treatment of low back pain (LBP) associated with elderly degenerative lumbar scoliosis (DLS) remains controversial. We have developed percutaneous intervertebral-vacuum polymethylmethacrylate injection (PIPI) targeting to the intervertebral vacuum as a minimally invasive surgery. The present study compared the long-term clinical outcomes of PIPI to that of nonoperative treatment. METHODS: Patients with de novo DLS, aged ≥ 65 years, who had LBP with visual analog scale (VAS) of ≥ 50 for ≥ 6 months with intervertebral vacuum on computed tomography and bone marrow edema (BME) on magnetic resonance imaging were included. The clinical outcomes were evaluated using VAS and the Oswestry Disability Index (ODI) at baseline, 1, 6, 12, 24 months, and at the final follow-up. The course of BME was also evaluated. RESULTS: One hundred and one patients underwent PIPI and 61 received nonoperative treatment. The mean follow-up duration after PIPI and nonoperative treatment was 63.7 ± 32.4 and 43.9 ± 20.9 months, respectively. VAS and ODI after PIPI were significantly improved compared to post-nonoperative treatment. BME decreased substantially in the PIPI group and it was significantly correlated with VAS and ODI improvement. Following PIPI, LBP recurred in 28 patients (35%). LBP recurrence was identified at the same level of PIPI in 10 patients, at the adjacent level of PIPI in 11 patients, and at the non-adjacent level of PIPI in seven patients. Eighteen patients underwent additional PIPIs, and both VAS and ODI were significantly improved after additional PIPIs. CONCLUSION: Bone marrow lesions of the endplate are strongly associated with the presence of LBP. PIPI can be considered as an effective, safe and repeatable treatment for LBP in elderly DLS patients.

The correlation between sagittal spinopelvic alignment and degree of lumbar degenerative spondylolisthesis.

BACKGROUND: Recently, several authors reported that a high pelvic incidence (PI) might be a predisposing factor to the development of anterior slip in the vertebral body in degenerative spondylolisthesis (DS). The purpose of this study was to analyze patients with DS using a multiple linear regression model, in terms of the correlation between the sagittal spinopelvic parameters and the severity of slip in each lumbar spine, including both anterior and posterior directions. METHODS: Standing lateral radiographs were taken of 104 patients (59 women and 45 men) with lower back pain. The spinopelvic parameters, including PI, sacral slope (SS) and pelvic tilt (PT), angle of thoracic kyphosis (TK), angle of lumbar lordosis (LL), and sagittal vertical axis offset (SVA) were measured. Additionally, the %Slip was measured at each level between the L1 and L5. The slip direction was presented as plus to the anterior, and minus to the posterior. RESULTS: The PI, SS, and/or LL correlate with L3, L4, and/or L5%Slips. The TK and SVA did not correlate with %Slip. A multiple linear regression model shows that PI and LL were significant predictors for L4 %Slip. The ROC curve demonstrated a PI cutoff value of 51.3° and an LL cutoff value of 45.0° to be predictors of anterior slip at L4. Also, our regression models revealed that PI for L3 %Slip and SS for L5 %Slip constitute significant risk factors, while determination coefficients were low. CONCLUSIONS: Our results suggest that high PI and LL are significant predictors for L4 anterior slip. At L4, the anterior slip risk-factor cutoff value was 51.3° for PI and 45.0°for LL. Additionally, our results suggest that high PI and SS could comprise risk factors for L3 anterior slip and L5 anterior slip, respectively.

Transforaminal percutaneous endoscopic discectomy for lumbar disc herniation in athletes under the local anesthesia.

BACKGROUND: Percutaneous endoscopic discectomy (PED) has been reported to be less invasive and effective procedure for lumbar disc herniation (LDH). Damage to the back muscle is considered minimal, which is particularly important for athletes. However, the results of PED for LDH in athletes have not been reported well. The purpose of this study was to evaluate the clinical outcomes of PED for LDH in athletes. METHODS: We retrospectively analyzed 21 athlete patients with LDH who had undergone PED. All patients received athletic rehabilitation immediately after surgery. The clinical outcomes were evaluated from the visual analogue scale (VAS) for leg pain and low back pain (LBP), the Oswestry Disability Index (ODI), complications and periods of return to sport. RESULTS: There were 18 men and 3 women, and the mean age at the time of surgery was 22.9 years (range: 15-43 years). The mean VAS scores for leg pain before and after surgery were 64.3 ± 2.7 mm and 12.4 ± 1.4 mm, respectively. The mean VAS scores for LBP before and after surgery were 62.1 ± 2.2 mm and 10.5 ± 1.1 mm, respectively. The mean ODI scores before and after surgery were 31.3 ± 14.0% and 14.6 ± 7.1%, respectively. The VAS for leg pain, as well as the LBP and ODI, significantly improved after surgery. There were no complications related to the surgery. Ninety-five percent (20/21) returned to play sports at the same performance level as before the procedure by an average of 9.2 weeks after PED. CONCLUSIONS: PED is a minimally invasive and effective procedure for patients with LDH, especially in athletes. Not only the patients' leg pain but also their discogenic LBP improved. PED has the benefits of preservation of normal posterior structures and a faster return to sports.

Local administration of WP9QY (W9) peptide promotes bone formation in a rat femur delayed-union model.

The WP9QY peptide (W9) consists of nine amino acids. It binds to RANKL and blocks RANKL-induced increases in bone resorption and osteoclastogenesis. W9 has a unique effect on the coupling mechanism between osteoclasts and osteoblasts, which promotes bone formation while working to suppress bone resorption. In this study, with the aim of clinical application of W9 for fracture treatment, we aimed to clarify the bone repair-promoting effect of W9 when administered locally to a rat femur model of delayed union. Using Sprague-Dawley rats, a model of delayed union was created in the right femur by cauterizing the periosteum. Injection of W9 (1 mg in 100 µl) or phosphate-buffered saline (PBS) (100 µl) at the fracture site was performed at the operation and every week thereafter until death (sacrifice). The bone union rate was 14% in the PBS group and 57% in the W9 group at 8 weeks postoperatively. The X-ray score of the W9 group was significantly higher than that of the PBS group at 8 weeks postoperatively. When bone morphometry was analyzed by micro-computed tomography (CT), total callus volume (TV) and mineralized callus bone volume (BV) were measured. TV showed no significant difference between the two groups, but BV/TV was significantly higher in the W9 group. This finding suggests that local administration of W9 can promote bone maturation from callus and can be considered to contribute to fracture healing. These results reveal that W9 has an effect on fractures of promoting healing and could be applied as a fracture treatment.

The safety and efficacy of magnetic targeting using autologous mesenchymal stem cells for cartilage repair.

PURPOSE: A new cell delivery system using magnetic force, termed magnetic targeting, was developed for the accumulation of locally injected cells in a lesion. The aim of this study was to assess the safety and efficacy of mesenchymal stem cell (MSC) magnetic targeting in patients with a focal articular cartilage defect in the knee. METHODS: MSC magnetic targeting for five patients was approved by the Ministry of Health Labour and Welfare of Japan. Autologous bone marrow MSCs were cultured and subsequently magnetized with ferucarbotran. The 1.0-T compact magnet was attached to a suitable position around the knee joint to allow the magnetic force to be as perpendicular to the surface of the lesion as possible. Then 1 × 107 MSCs were injected into the knee joint. The magnet was maintained in the same position for 10 min after the MSC injection. The primary endpoint was the occurrence of any adverse events. The secondary endpoints were efficacy assessed by magnetic resonance imaging (MRI) T2 mapping and clinical outcomes using the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation and the Knee Injury and Osteoarthritis Outcome Score (KOOS). RESULTS: No serious adverse events were observed during the treatment or in the follow-up period. Swelling of the treated knee joint was observed from the day after surgery in three of the five patients. The swelling resolved within 2 weeks in two patients. MRI showed that the cartilage defect areas were almost completely filled with cartilage-like tissue. MOCART scores were significantly higher 48 weeks postoperatively than preoperatively (74.8 ± 10.8 vs 27.0 ± 16.8, p = 0.042). Arthroscopy in three patients showed complete coverage of their cartilage defects. Clinical outcome scores were significantly better 48 weeks postoperatively than preoperatively for the IKDC Subjective Knee Evaluation (74.8 ± 17.7 vs 46.9 ± 17.7, p = 0.014) and knee-related quality-of-life (QOL) in the KOOS (53.8 ± 26.4 vs 22.5 ± 30.8, p = 0.012). CONCLUSION: Magnetic targeting of MSCs was safely performed and showed complete coverage of the defects with cartilage-like tissues and significant improvement in clinical outcomes 48 weeks after treatment. The magnetic targeting of MSCs is useful as a minimally invasive treatment for cartilage repair. LEVEL OF EVIDENCE: IV.

Discrimination of a nerve fiber that is the origin of a cauda equina tumor using acetylcholinesterase staining.

Spinal nerve sheath tumors are well known to typically originate from dorsal sensory nerve roots. However, it is difficult to anatomically identify the origin in the case of cauda equina tumors. In this study, we aimed to ascertain whether a cauda equina nerve root removed with a nerve sheath tumor was a motor nerve using acetylcholinesterase (AchE) staining. Nerve rootlet sections removed with tumors were stained for AchE using the AchE Rapid Staining Kit. Additionally, we performed intraoperative motor-evoked potential (MEP) monitoring following either transcranial electrical stimulation (TES) or electrical stimulation of nerve rootlets. The muscular strength of the lower extremities was assessed bilaterally before and after surgery using manual muscle testing. An AchE-positive motor nerve rootlet that was the origin of a cauda equina tumor was observed in one of the 12 patients. In this patient, a MEP in the right quadriceps evoked by electrical stimulation of this rootlet was detected. TES-MEP showed a 30% decrease in the amplitude in the right quadriceps evoked after tumor resection with this nerve rootlet. However, the motor strength in both lower extremities did not change after surgery. AchE staining and intraoperative MEP monitoring could detect the motor nerve rootlet that was the origin of a cauda equina tumor. Nerve sheath tumors originating from the motor nerve might be rare even in cauda equina.

The effect of administration of double stranded MicroRNA-210 on acceleration of Achilles tendon healing in a rat model.

BACKGROUND: Achilles tendons heal slower than other tissues, therefore requiring the developmnent of a strategy for accelerating the process. Vascular supply plays an important role in primary tendon healing, especially during the early healing phase. MicroRNA (miR)-210 has been reported as being crucial for angiogenesis, which is a key factor of tissue repair. We report herein that local injection of synthetic miR-210 into the injured Achilles tendon of a rat accelerated healing of the tendon. METHODS: Achilles tendons were transected and repaired via the Kessler suture technique in Sprague-Dawley rats. Then, double stranded (ds) miR-210 was injected into the repaired sites. The control group was injected with non-functioned dsRNA. At 2, 6 and 12 weeks, histological evaluations were performed. At two and six weeks, mechanical testing and angiogenesis were evaluated. Gene expression analysis using real-time polymerase chain reaction (PCR) and immunohistochemistry were performed at two weeks. RESULT: At two and six weeks, regular dense collagen tissue in the miR-210 group was observed and the diameter of collagen fiber in the miR-210 group was significantly higher than in the control. At two weeks, the ultimate failure load was significantly higher than in the control group, and expression of VEGF, FGF2 and type I collagen was upregulated. Abundant vessels in the miR-210 group were observed at two weeks, but there was no significant difference in vessel numbers between the two groups at six weeks. At 12 weeks, repaired Achilles tendons in the miR-210 group consisted of parallel and dense fibers, whereas wavy and loose fibers were still observed in the control group. CONCLUSION: The current study showed that single local injection of synthetic miR-210 promotes Achilles tendon healing in the early phase.

Clinical results of microsurgical bilateral decompression via unilateral approach for lumbar canal stenosis with multiple-level involvement.

OBJECT: Microsurgical decompression of the lumbar spine is a beneficial approach for selected patients of lumbar spinal stenosis (LSS). The purpose of this prospective study was to describe the clinical results of surgical treatment for microsurgical bilateral decompression via unilateral approach on patients with LSS with multiple-level involvement. MATERIALS AND METHODS: Seventy-three consecutive patients who had microsurgical bilateral decompression via unilateral approach of more than two spinal levels were included in this study. Seventy-seven patients who had surgery at a single level over the same time periods were compared as a single-level LSS group. RESULTS: The preoperative Japanese Orthopaedic Association scores averaged 11.7 points, and the postoperative scores averaged 21.2 points with an average recovery rate (RR) of 56% in the multiple-level LSS group. There was no significant difference in the RR between the groups. There were no major complications related to the surgery in the both groups. CONCLUSION: Microsurgical bilateral decompression via unilateral approach was a useful and safe operative procedure for LSS patients. Sufficient clinical results that were comparable to single-level LSS patients were obtained even in the patients with multiple-level LSS, if the patient were correctly selected and the microsurgical decompression surgery were carefully performed.