Ryota Takatori

In vivo measurements of lumbar segmental motion during axial rotation in asymptomatic and chronic low back pain male subjects

Study Design. Twenty male volunteers in their 30s (10 asymptomatic and 10 chronic low back pain) were passively rotated and CT scanned to determine lumbar segmental motion. Objectives. To determine the feasibility of measuring 3-dimensional segmental motion in vivo in pain subjects. Summary of Background Data. Axial rotational spinal instability has been implicated as a potential cause of low back pain. Previous studies have not compared 3-dimensional segmental motions between healthy and symptomatic subjects due to torsion. Methods. Lumbar segmental motions were calculated using volume merge method in 3 major planes from 3-dimensional CT reconstructions. Disc degeneration grade was analyzed from MRI using the Thompsons grading method. Results. All subjects could perform the imaging study without significant increase in pain. No differences were seen in disc degeneration grade or segmental motions between the 2 groups. Segmental motion differences were seen in torsion, lateral bending, and frontal translation based on spinal level. Conclusions. Current noninvasive CT-based method is feasible for use in healthy and low back pain subjects. Measured segmental motions were similar to other studies in torsion; however, other motions have not been measured previously.

Load Response of the Tarsal Bones in Patients with Flatfoot Deformity: In Vivo 3D Study

Background: The objective of this study was to evaluate the bone rotation of each joint in the hindfoot and compare the load response in healthy feet with that in flatfeet by analyzing the reconstructive three-dimensional (3D) CT image data during weightbearing. Methods: CT scans of 21 healthy feet and 21 feet with flatfoot deformity were taken in non-load condition followed by full-body weightbearing load condition. The images of the hindfoot bones were reconstructed into 3D models. The volume merge method in three planes was used to calculate the position of the talus relative to the tibia in the tibiotalar joint, the navicular relative to the talus in talonavicular joint, and the calcaneus relative to the talus in the talocalcaneal joint. Results: The talar position difference to the load response relative to the tibia in the tibiotalar joint in a flatfoot was 1.7 degrees more plantarflexed in comparison to that in a healthy foot (p = 0.031). The navicular position difference to the load response relative to the talus in the talonavicular joint was 2.3 degrees more everted (p = 0.0034). The calcaneal position difference to the load response relative to the talus in the talocalcaneal joint was 1.1 degrees more dorsiflexed (p = 0.0060) and 1.7 degrees more everted (p = 0.0018). Conclusion: Referring to previous cadaver study, regarding not only the cadaveric foot, but also the live foot, joint instability occurred in the hindfoot with load in patients with flatfoot. Clinical Relevance: The method used in this study might be applied to clinical analysis of foot diseases such as the staging of flatfoot and to biomechanical analysis to evaluate the effects of foot surgery in the future. Level of Evidence: III

In Vivo Three-Dimensional Analysis of Hindfoot Kinematics:

Background: Knowledge of normal bone motion of the foot is important for understanding the gait as well as for various pathologies; however, the pattern of 3D motion is not completely understood. The aim of this study was to quantify the in vivo motion of the tibiotalar joint, talocalcaneal joint, and talonavicular joint in normal adult feet using a noninvasive (e.g., nonsurgical) measurement technique. Materials and Methods: CT images were taken of both feet of ten normal young adults (six males, four females) in neutral, plantarflexion, and dorsiflexion positions of the ankle joint, from which 3D virtual models were made of each mid-hind foot bones. The 3D bone motion of these models was calculated using volume merge methods in three major planes. These data were used to analyze the relationship between the motion of the ankle joint and each other joint. Results: Tibiotalar rotation was observed in dorsiflexion, abduction, and eversion during maximal dorsiflexion of the ankle joint. Talocalcaneal and talonavicular rotation was very small because the ankle joint motion was limited to the sagittal plane. Tibiotalar rotation was also observed in plantarflexion and adduction during maximal plantarflexion of the ankle joint, and talocalcaneal rotation was very small. Talonavicular rotation was observed in plantarflexion and inversion. The motion of the x-axis and the z-axis of tibiotalar joint, and the x-axis and the y-axis of the talonavicular and talocalcaneal joint were associated with the ankle motion. Conclusion: Bone motion could be easily and accurately calculated using volume merge methods more effectively than it could with other methods. Clinical Relevance: The data elucidates the baseline segmental motion for comparison with symptomatic subjects which could help us to better understand pathokinematics of various foot and ankle pathologies.

Three-dimensional morphology and kinematics of the craniovertebral junction in rheumatoid arthritis.

Study Design. A case-series study. Objectives. To measure the 3-dimensional (3D) morphology and kinematics of the craniovertebral junction (CVJ) using a 3D computed tomography (CT) model; to reveal abnormal patterns and the relationships between pathology and kinematics. Summary of Background Data. Evaluations using radiography, 2-dimensional (2D) CT and magnetic resonance imaging have limitations because of the complex 3D structure of the CVJ. Methods. Twenty-four rheumatoid arthritis patients (21 females, 3 males) with cervical involvement underwent CT scanning of the cervical spine from the basilar process of the occipital bone to the first thoracic vertebra in neutral and flexed positions. The 3D morphology of the occipital condyle, atlas, and axis were classified based on the type of deformity observed. Periodontoid lesions (continuous bony lesions between the atlas and the odontoid process) were also noted. The 3D kinematics in the atlanto-occipital and atlantoaxial joints were evaluated using the volume merge method. Results. Deformities in the atlanto-occipital joints appeared more frequently than those in the atlantoaxial joints. The most common instability pattern was flexural rotation during flexion at the CVJ. The direction of translational motions during flexion was posterior in the atlanto-occipital joint and anterior and caudal in the atlantoaxial joint. Conclusion. The results suggest that bilateral occipital condyle deformation, unilateral and bilateral mass collapse, and periodontoid lesions may affect flexion/extension rotational instability in the atlantoaxial joint. In addition, unilateral occipital condyle deformation and atlantoaxial joint stability may affect sagittal translational instability to the posterior side in the atlanto-occipital joint. The noninvasive 3D CT imaging technique employed here would be useful for predicting the prognosis of patients with rheumatoid deformities at the CVJ.

Effect of electroacupuncture on the healing process of tibia fracture in a rat model: a randomised controlled trial

Background Electrical stimulation is used to promote bone reunion, and is most effective when applied directly to the fracture site. Objective To examine the effects of electroacupuncture (EA) on the healing process of tibia fracture in a rat model. Methods Thirty 12-week-old male Wistar rats underwent unilateral open osteotomies of the tibiae. The rats were then assigned randomly to three groups: EA group (n=10), sham group (n=10) and control group (n=10). In the EA group, a cathodal electrode was connected to an acupuncture needle percutaneously penetrated directly at the surgery site, while an acupuncture needle inserted at 15 mm proximal to the surgery site was used as an anodal electrode. EA (50 Hz, 20 μA, 20 min) was performed daily for 3 weeks. In the sham group the acupuncture needles were inserted at the same sites but no electrical stimulation was given and in the control group, no treatment was given. The response was evaluated at 1, 3, 4 and 6 weeks after surgery by radiographic, macroscopic and mechanical examinations. Results The EA group showed accelerated bone healing (EA group 29.92±4.55 mm2, sham group 26.46±5.21 mm2, control group 26.19±2.81 mm2, p<0.05 at 3 weeks) and accretion of the callus (radiographic evaluation: EA group 35.66±4.37 mm2, sham group 32.60±5.73 mm2, control group 29.72±6.39 mm2, p<0.05 at 6 weeks) compared with the other groups. Mechanical testing also showed an excellent result (EA group 16.54±9.92 N, sham group 7.13±3.57 N, control group 6.67±3.12 N, p<0.05) at 6 weeks in the EA group compared with the other groups. There was no difference between the sham and control groups in any evaluation. Conclusion The use of EA enhanced callus development and bone mineralisation during the bone healing process.

Features of hindfoot 3D kinetics in flat foot in ankle-joint maximal dorsiflexion and plantarflexion

BackgroundIt is difficult to evaluate the kinematics of flat foot from 2D images, and no definitive methods have so far been established to diagnose flat foot. This study evaluated hindfoot kinetics through the progression of posterior tibial tendon dysfunction (PTTD) in patients with stages II and III PTTD flat foot compared with those in normal patients under dorsiflexion and plantarflexion conditions using 3D computed tomography (CT) reconstruction images.MaterialsCT images were taken of 26 normal and 32 flat feet in neutral, plantarflexion, and dorsiflexion positions of the ankle joint, from which 3D virtual models were made of each hindfoot bone. The 3D bone motion of these models was calculated using volume merge methods in three major planes.ResultsTibiotalar-joint motion in ankle-joint plantarflexion became less plantarflexed (normal −41.2°, stage II −33.5°, stage III −25.3°) and less adducted (normal −13.9°, stage II −10.7°, stage III −5.6°) as the stage progressed. Talocalcaneal-joint motion in stage III became more plantarflexed (normal −0.8°, stage II −3.0°, stage III −8.7°) and more adducted (normal −0.3°, stage II −4.7°, stage III −10.3°) as the stage progressed. Talonavicular-joint motion in stage III became more plantarflexed (normal −7.2°, stage II −7.6°, stage III −14.9°) and more adducted (normal 1.0°, stage II −7.3°, stage III −17.9°) as the stage progressed.ConclusionsTibiotalar-joint plantarflexion decreased and talocalcaneal and talonavicular-joint adduction increased in the maximal ankle-joint plantarflexion in stage II in comparison with normal cases. Tibiotalar-joint plantarflexion and adduction were decreased and of the talocalcaneal and talonavicular joints increased in stage III in comparison with stage II cases.

Ligamentum flavum hypertrophy in asymptomatic and chronic low back pain subjects.

Purpose To examine ligamentum flavum thickness using magnetic resonance (MR) images to evaluate its association with low back pain symptoms, age, gender, lumbar level, and disc characteristics. Materials and Methods Sixty-three individuals were part of this IRB-approved study: twenty-seven with chronic low back pain, and thirty-six as asymptomatic. All patients underwent MR imaging and computed tomography (CT) of the lumbar spine. The MR images at the mid-disc level were captured and enlarged 800% using a bilinear interpolation size conversion algorithm that allowed for enhanced image quality. Ligamentum flavum thickness was assessed using bilateral medial and lateral measurements. Disc height at each level was measured by the least-distance measurement method in three-dimensional models created by CT images taken of the same subject. Analysis of variance and t-tests were carried out to evaluate the relationship between ligamentum flavum thickness and patient variables. Results Ligamentum flavum thickness was found to significantly increase with older age, lower lumbar level, and chronic low back pain (p < 0.03). No difference in ligamentum flavum thickness was observed between right and left sided measurements, or between male and female subjects. Disc height and both ligamentum flavum thickness measurements showed low to moderate correlations that reached significance (p < 0.01). Additionally, a moderate and significant correlation between disc degeneration grade and ligamentum flavum thickness does exist (p <0.001). Conclusion By measuring ligamentum flavum thickness on MR images at two different sites and comparing degrees of disc degeneration, we found that ligamentum flavum thickness may be closely related to the pathogenesis of pain processes in the spine.

Prevention of neurological complications using a neural monitoring system with a finger electrode in the extreme lateral interbody fusion approach

OBJECTIVE Extreme lateral interbody fusion (XLIF) is a minimally disruptive surgical procedure that uses a lateral approach. There is, however, concern about the development of neurological complications when this approach is used, particularly at the L4-5 level. The authors performed a prospective study of the effects of a new neural monitoring system using a finger electrode to prevent neurological complications in patients treated with XLIF and compared the results to results obtained in historical controls. METHODS The study group comprised 36 patients (12 male and 24 female) who underwent XLIF for lumbar spine degenerative spondylolisthesis or lumbar spine degenerative scoliosis at L4-5 or a lower level. Using preoperative axial MR images obtained at the mid-height of the disc at the treated level, we calculated the psoas position value (PP%) by dividing the distance from the posterior border of the vertebral disc to the posterior border of the psoas major muscle by the anteroposterior diameter of the vertebral disc. During the operation, the psoas major muscle was dissected using an index finger fitted with a finger electrode, and threshold values of the dilator were recorded before and after dissection. Eighteen cases in which patients had undergone the same procedure for the same indications but without use of the finger electrode served as historical controls. Baseline clinical and demographic characteristics, PP values, clinical results, and neurological complications were compared between the 2 groups. RESULTS The mean PP% values in the control and finger electrode groups were 17.5% and 20.1%, respectively (no significant difference). However, 6 patients in the finger electrode group had a rising psoas sign with PP% values of 50% or higher. The mean threshold value before dissection in the finger electrode group was 13.1 ± 5.9 mA, and this was significantly increased to 19.0 ± 1.5 mA after dissection (p < 0.001). A strong negative correlation was found between PP% and threshold values before dissection, but there was no correlation with threshold values after dissection. The thresholds after dissection improved to 11 mA or higher in all patients. There were no serious neurological complications in any patient, but there was a significantly lower incidence of transient neurological symptoms in the finger electrode group (7 [38%] of 18 cases vs 5 [14%] of 36 cases, p = 0.047). CONCLUSIONS The new neural monitoring system using a finger electrode may be useful to prevent XLIF-induced neurological complications.

Posterior tibial tendon tenosynovectomy for rheumatoid arthritis: a report of three cases.

Posterior tibial tendon dysfunction (PTTD) has been cited as a cause of pes planovalgus deformity.9 In patients with rheumatoid arthritis (RA), PTTD may be caused by tenosynovitis around the posterior tibial (PT) tendon,5 but there are few reports regarding the effects of tenosynovectomy. We report three patients with RA and PTTD classified as 1 or 2 according to the classification of Pomeroy et al.13 who did not respond to conventional therapy including corticosteroid injection and were treated with tenosynovectomy. The American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale was used for clinical evaluation. For radiographic evaluation, gadoliniumdiethylenetriamine pentaacetic acid (Gd-DTPA) enhanced MRI and anteroposterior and lateral radiographs of the foot were used.3,15

Clinical Outcome of Muscle-Preserving Interlaminar Decompression (MILD) for Lumbar Spinal Canal Stenosis: Minimum 5-Year Follow-up study

Introduction Favorable short-term outcomes have been reported following muscle-preserving interlaminar decompression (MILD), a less invasive decompression surgery for lumbar spinal canal stenosis (LSCS). However, there are no reports of mid- to long-term outcomes. The purpose of this study was to evaluate the clinical outcomes five or more years after treatment of LSCS with MILD. Methods Subjects were 84 cases with LSCS (44 males; mean age, 68.7 years) examined five or more years after MILD. All patients had leg pain symptoms, with claudication and/or radicular pain. The patients were divided into three groups depending on the spinal deformity: 44 cases were without deformity (N group); 20 had degenerative spondylolisthesis (DS group); and 20 had degenerative scoliosis (DLS group). The clinical evaluation was performed using Japanese Orthopedic Association (JOA) scores, and revision surgeries were examined. Changes in lumbar alignment and stability were evaluated using plain radiographs. Results The overall JOA score recovery rate was 65.5% at final follow-up. The recovery rate was 69.5% in the N group, 65.2% in the DS group, and 54.0% in the DLS group, with the rate of the DLS group being significantly lower. There were 16 revision surgery cases (19.0%): seven in the N group (15.9%), three in the DS group (15.0%) and six in the DLS group (30.0%). There were no significant differences between pre- and postoperative total lumbar alignment or dynamic intervertebral angle in any of the groups, slip percentage in the DS group, or Cobb angle in the DLS group. Conclusions The mid-term clinical results of MILD were satisfactory, including in cases with deformity, and there was no major impact on radiologic lumbar alignment or stability. The clinical outcomes of cases with degenerative scoliosis were significantly less favorable and the revision rate was high. This should be taken into consideration when deciding on the surgical procedure.