Hiroshi Yonezu

Characteristics of bone mineral density and soft tissue composition of obese Japanese women: Application of dual-energy X-ray absorptiometry

Abstract: We studied the characteristics of bone mineral density (BMD) and soft tissue composition in obese Japanese women using dual-energy X-ray absorptiometry. Eighty-nine women, aged 45–85 years, were divided into three groups according to their body mass index (BMI): a thin group (n = 38; BMI < 21), a standard weight group (n = 31; BMI, 21–25), and an obese group (n = 20; BMI ≥ 25). The mean BMD of the second to fourth lumbar vertebrae and BMD of the lumbar spine, thoracic spine, pelvis, legs, and ribs of the thin group were significantly lower than those of the standard weight group or the obese group (P < 0.05), whereas no significant difference in total body BMD was observed among the three groups. There was a significant difference in total and regional fat mass among the three groups (P < 0.05). Lean mass of legs and total lean mass showed a significant difference between the thin group and the obese group (P < 0.05). The results showed that obesity was associated with higher BMD of weight bearing-bones and ribs, high total and regional fat mass, and high lean mass of bilateral legs and total lean mass. We suggest that obesity may contribute to the prevention of bone loss of weight-bearing bones and ribs and muscular atrophy of the legs.

Effects of sciatic neurectomy on the femur in growing rats: application of peripheral quantitative computed tomography and Fourier transform infrared spectroscopy.

Abstract: The effects of unilateral sciatic neurectomy (USN) on the development of the femur were studied in 15 growing Wistar-derived rats (age, 5 weeks). The rats were divided into four groups: USN-operated group (right femur), USN-nonoperated group (left femur), sham-operated group (right femur), and sham-nonoperated group (left femur). Bone mineral density (BMD), bone mineral content (BMC), bone area, periosteal circumference, and endosteal circumference were measured by peripheral quantitative computed tomography (pQCT) and the mineral/matrix ratio was evaluated by Fourier transform infrared spectroscopy (FTIR). The USN-operated group showed a significant decrease in cortical BMC, bone area, and periosteal circumference compared with the other groups (P < 0.05). The cortical BMD did not vary significantly between the groups. In the cancellous bone, the USN-operated group showed a significant decrease in BMD and BMC at the metaphysis compared with the other groups (P < 0.05). The mineral/matrix ratio of the cortical bone did not differ significantly between the USN-operated and USN-nonoperated groups. These results suggest that in cortical bone, USN inhibits periosteal bone formation but has no significant effect on the mineral/matrix ratio of cortical bone in femurs. In cancellous bone, USN induces bone loss at the metaphysis.

Characteristics of regional bone mineral density and soft tissue composition in patients with atraumatic vertebral fractures

Abstract To clarify the characteristics of total body and regional bone mineral density (BMD) and soft tissue composition in patients with atraumatic vertebral fractures (AVF), we measured total body and regional BMD, lean mass, and fat mass using dual-energy X-ray absorptiometry. Sixty-four women, aged 55–75 years, were divided into two groups: women with AVF (fracture group, n = 30) and women without AVF (nonfracture group, n = 34). Mean BMD of the second to fourth lumbar vertebrae (L2–4BMD), regional BMD, and soft tissue mass were measured. Regional BMD was measured in the head, arms, legs, ribs, thoracic vertebrae, lumbar vertebrae, and pelvis. Lean mass and fat mass of head, arms, legs, and trunk were measured. L2–4BMD, total body BMD, and BMD of the lumbar spine, thoracic spine, and pelvis of the fracture group were significantly lower than those of the nonfracture group (P < 0.001). Total lean and fat mass of the fracture group tended to be lower than that of the nonfracture group. The results suggest that BMD of weight-bearing bones, except for that of the bones of the legs of the fracture group, is significantly lower than that of the nonfracture group, and that total body lean and fat mass may be a predictor for AVF.

Effects of lower-leg lengthening on bone mineral density and soft tissue composition of legs in a patient with achondroplasia

tall and weighed 38 kg; she was remarkably short compared with normal girls of the same age. She had an enlarged neurocranium with frontal bossing and flattening of the nasal bridge. Her features included normal height of the trunk height with rhizomelic shortening and genu varum. Lower-leg lengthening was performed on bilateral tibias by means of callus distraction (callotasis) using a unilateral dynamic external fixator. As for schedule of leg lengthening, the waiting period was 10 days, distraction period was 180 days at a rate of 1 mm/day, neutralization period was 84 days, and dynamic load period was 98 days. After the dynamic load period, the external fixation was removed from the tibial shaft. As a result, overall treatment time was 372 days in this case, and the healing index was 42 days/cm. On the 40th day following the operation, the patient started to walk with two axillary crutches. The mean BMD of the second to fourth lumbar vertebrae (L2-4BMD), total body BMD, and soft tissue mass were measured by DXA using a Hologic QDR 2000 (Waltham, MA, USA). As shown in Fig. 1, the BMD (g/ cm2) of head, upper or lower extremities, ribs, thoracic vertebrae, lumbar vertebrae, and pelvis was measured. The lean mass (g) and the fat mass (g) of head, arms, legs, and trunk were measured with a tissue bar. In addition, to assess bone mineral metabolism during and after leg lengthening, serum alkaline phosphatase (Alp) and osteocalcin were measured before leg lengthening, during the distraction period, and during the dynamic load period.

A new concept of transforaminal ventral facetectomy including simultaneous decompression of foraminal and lateral recess stenosis: Technical considerations in a fresh cadaver model and a literature review

Percutaneous endoscopic surgery for the lumbar spine, which was established in the last decade, requires only an 8-mm skin incision and causes minimal damage to the paravertebral muscles; thus, it is considered to be a minimally invasive technique for spinal surgery. It has been used to perform percutaneous endoscopic discectomy via two main approaches: the TF approach is a posterolateral one through the intervertebral foramen and can be done under local anesthesia; the IL approach is a more traditional one through the interlaminar space and is difficult to perform under local anesthesia. Recently, these techniques have been applied for lumbar spinal stenosis (LSS), the TF method for foraminal stenosis under local anesthesia, and the IL method for central and lateral recess stenosis under general anesthesia. In this study, using a fresh human cadaver model, we performed simultaneous decompression of the lateral recess and foraminal stenosis at L4-5 using the TF approach. Computed tomography confirmed enlargement of the lateral recess and intervertebral foramen. This technique, which can be performed under local anesthesia, should benefit elderly patients with LSS and poor general condition due to multiple comorbidities. Finally, we introduce the concept of percutaneous transforaminal ventral facetectomy using a spinal percutaneous endoscope. J. Med. Invest. 64: 1-6, February, 2017.

Cementless calcar-replacement stem with integrated greater trochanter plate for unstable intertrochanteric fracture in very elderly patients:

Purpose: To evaluate the clinical results of rigid fixation of the greater trochanter fragment through a consecutive hemiarthroplasty series using a cementless and modular calcar-replacement prosthesis with an integrated plate (MOD-Centaur stem) with 1-year follow-up in very elderly patients with unstable intertrochanteric fractures. Methods: We assessed 44 consecutive very elderly patients (age >85 years; 2 men, 42 women; mean age at surgery: 89.6 years) with an unstable intertrochanteric fracture who underwent bipolar hemiarthroplasty using the MOD-Centaur stem by the same surgeon. Operative time and blood loss were evaluated, and postoperative complications and mortality rate within 1 year were assessed. Bony union of the greater trochanter was evaluated using plain X-ray images at least 6 months postoperatively. Walking ability was evaluated at the time of discharge and at 1 year postoperatively. Results: The mean operative time was 95.8 min, and the mean intraoperative blood loss was 358.0 mL. Postoperative peripheral infection occurred in one patient. Four patients died within 1 year postoperatively (mortality rate: 9.1%). Bony union of the greater trochanter was achieved in all the patients who had a plain X-ray taken at least 6 months postoperatively. At 1-year follow-up, 20 patients could walk independently. Conclusion: Hemiarthroplasty using the MOD-Centaur stem for unstable intertrochanteric fracture in very elderly patients offers favorable outcomes. These findings encourage early walking without any loading limitations, despite severe osteoporosis, and emphasize the importance of greater trochanteric fixation, which reconstructs the mechanism of the gluteus medius muscle.

Successful Endoscopic Surgery for L5 Radiculopathy Caused by Far-Lateral Disc Herniation at L5-S1 and L5 Isthmic Grade 2 Spondylolisthesis in a Professional Baseball Player

ABSTRACT Background: We report the case of a professional baseball player who had severe leg pain due to lumbar lateral disc herniation at L4-5 and isthmic spondylolisthesis at L5 (double crash syndrome). For early recovery to competitive level, we performed minimally invasive endoscopic decompression surgery without fusion. There are few reports to discuss the usefulness of minimally invasive treatment for top athletes. Methods: A 29-year-old professional baseball player who played catcher was referred to us with a complaint of right leg pain. The previous doctor diagnosed far-lateral disc herniation and Grade 2 isthmic spondylolisthesis and recommended arthrodesis at L5-S1 as treatment for both pathologies. Radiological imaging showed that the right L5 nerve root was impinged by the 2 lumbar disorders, namely, far-lateral disc herniation and a ragged edge around a pars defect. We had taken into account the patients occupation and his wish to avoid a lengthy sick leave, and we had performed endoscopic decompression surgery during the offseason. The far-lateral disc herniation at L5-S1 was removed under local anesthesia by percutaneous endoscopic discectomy, after which the ragged edge at the pars defect was removed under general anesthesia using a microendoscopic discectomy system. Given that the patient did not have any low back pain, arthrodesis was not considered. Results: The leg pain resolved after surgery. The following year (2015), the patient resumed playing baseball from the beginning of the season and played in 41 games. In the 2016 season, he played in 71 games without any symptoms. No further slippage was observed at radiological follow up 1 year after the surgery. Conclusions: Minimally invasive endoscopic surgery is an option for radiculopathy in very active patients who need an early return to their previous level of physical activity.

Accurate diagnosis of chronic low back pain in a high-level college athlete: a case report

A 21-year-old woman who was high-level college softball player presented with a 6-month history of low back pain that had been treated unsuccessfully by medication at local clinics. There was tenderness in the left paravertebral muscle at the lower lumbar level. X-ray and computed tomography revealed congenital scoliosis and an L6 hemivertebra. Short tau inversion recovery magnetic resonance imaging showed a fluid collection at the left L6-S1 facet joint. We performed a diagnostic facet injection, consisting of 1% lidocaine and steroids, that was infiltrated into the left facet joint at L6-S1. Her persistent low back pain disappeared immediately after the facet block. We diagnosed left-sided facet arthritis at L6-S1. Due to her multiple congenital anomalies, excessive loading occurred at the facet joint. Therefore, we opted for conservative management, including mobilization of the thoracic spine and stretching of hamstrings and quadriceps. This case report underscores the importance of accurate diagnosis of low back pain and of the diagnostic utility of short tau inversion recovery magnetic resonance imaging and lumbar facet block in young athletes with chronic spinal pain. J. Med. Invest. 64: 313-316, August, 2017.

Utility of STIR-MRI in Detecting the Pain Generator in Asymmetric Bilateral Pars Fracture: A Report of 5 Cases

Lumbar spondylolysis usually occurs as a stress fracture in the pars interarticularis of the vertebra. It is a prevalent sports-related disorder and a common cause of low back pain. We encountered five athletes (4 males, 1 female) with severe low back pain. Mean age was 14.5 years. All five patients were found to have bilateral pars fracture. In all cases, staging based on the findings from computed tomography scan of the right and left pars fracture was different. On short tau inversion recovery magnetic resonance imaging (STIR-MRI) of the comparatively newer more recently injured side, high signal intensity changes were obvious and dominant at the intra- and extraosseous area, which would indicate tissue edema and/or bleeding. Furthermore, the imaging findings corresponded to the side of the low back pain. In conclusion, STIR-MRI can effectively distinguish between painful pars fracture and painless pars fracture.

Injury to the Obturator Artery During Periacetabular Osteotomy

Case:We describe a middle-aged woman who had undergone periacetabular osteotomy (PAO) on both hips successively within a two-year period. Although the first PAO was successfully performed on the right hip without any complications, injury to the obturator artery occurred during the subsequent PAO on the left hip. In this case, the obturator artery seemed to be injured at the medial base of the iliopectineal eminence during osteotomy. Conclusion:PAO has been employed as a reconstructive surgery for acetabular dysplasia. However, given the proximity of intrapelvic vascular structures, there is a risk of iatrogenic vascular injury.