Noriyuki Ishikawa

Surface strain distribution on thoracic and lumbar vertebrae under axial compression. The role in burst fractures.

STUDY DESIGN The surface strain distribution on the thoracic and lumbar vertebrae during axial compressive loading was examined. OBJECTIVES To examine the general mechanical behavior of the thoracic and lumbar vertebrae to evaluate their role in burst fractures. SUMMARY OF BACKGROUND DATA Burst fractures are generally characterized by injury to the middle column and fracturing of the superior endplate. However, results in previous biomechanical investigations have not shown how these fractures are initiated during compression. METHODS Twenty-one thoracic and lumbar vertebrae (5 T10, 10 L1, and 6 L4) with upper and lower vertebrae were studied. Three-axis rosette strain gauges were cemented to 11 sites on the vertebral surface. An axial compressive load was applied, and the strain was measured in each specimen. The strain recorded by each rosette gauge was converted into a tensile, compressive, and shear component. RESULTS The highest tensile and compressive strain was recorded at the base of the pedicle. Shear strain in the vertebral body was significantly higher than that in the lamina at all three spinal levels. At L1 and L4, the tensile strain at the superior vertebral rim was higher than that at the inferior rim. CONCLUSIONS The high tensile and compressive strains found at the base of the pedicle of T10, L1, and L4 indicate that the base of the pedicle is the site of fracture initiation. The higher tensile strain at the superior vertebral rim of L1 and L4 supports the clinical observation of the thoracolumbar burst fractures.

Case report 858

A case of postradiation osteosarcoma of the patella in a 54-year-old man was presented. The lesion in the patella was diffuse and highly sclerotic, and was partially radiolucent in radiographs. The whole patella was removed by Miyakawas method. Diagnostic criteria, clinical features, and radiographic findings of postradiation sarcoma were described. The rarity of osteosarcoma of the patella was emphasized.

Vertebral pedicle diameter as determined by computed tomography: inaccuracies observed by direct measurement of cadaveric lumbar spine

The isthmic diameter of the vertebral pedicle is an important dimension affecting the stability of transpedicular screwing. The isthmic diameter of the pedicle was measured in the lumbar spines of 18 Japanese cadavers (10 male, 8 female) by axial computed tomographic (CT) scan and directly with calipers. In L1 and L2, there was no significant difference between the average value of the isthmic diameter as determined by the two methods (Students t-test). However, in L3-5, the average value of the isthmic diameter as determined by axial CT scan was significantly greater than that given by caliper measurement. In view of the fact that caudally the longitudinal axis of the pedicle diverges to wards the mid-line of the vertebral body in the coronal plane, the plane of the CT scan cannot be parallel to the real isthmic diameter of the pedicle. Therefore, it is suggested that below L2 the diameter as determined by axial CT scanning is greater than the real isthmic diameter.

Enlargement of an osseous loose body in the cervical spine with cord compression

BACKGROUND CONTEXT Loose bodies in the spinal canal are extremely rare, with only two cases reported previously in the literature. PURPOSE To report a rare case of an osseous loose body in the cervical spine with radiographic evidence of dramatic enlargement of the loose body in the spinal canal over the course of 9 years. STUDY DESIGN/SETTING Case report. PATIENT SAMPLE A 50-year-old man presented with progressive numbness and weakness of the upper and lower extremities and swaying gait in 2007. He had a history of temporary incomplete tetraplegia after a fall in 1998. Magnetic resonance imaging revealed enlargement of the posterior mass-occupying lesion compressing the cord at C5-C6 over the course of 9 years. OUTCOME MEASURES Neurological examination with motor and sensory status. RESULTS Posterior decompressive laminectomy was performed. An isolated, smooth-surfaced, bony, hard mass was found between the ligamentum flavum and facet joint and removed. Histological examination demonstrated trabecular bone and peripheral cartilage mixed with fibrous and fibrocartilaginous tissue. Clinical evaluation of the patient 6 months postoperatively showed total resolution of neurological symptoms. CONCLUSION We report herein an extremely rare case of an osseous loose body in the spinal canal with cord compression. This report represents the first documented case of growth of a loose body in the spinal canal.

Limaprost or pregabalin: preoperative and postoperative medication for pain due to lumbar spinal stenosis

We aimed to evaluate the incidence of (and risk factors for) postoperative pregabalin and/or limaprost to treat persistent numbness and/or pain of the lower extremities after lumbar spinal stenosis (LSS) surgery.

Chronic expanding hematoma resulting from osteoporotic insufficiency fracture of the pubis

Chronic expanding hematoma (CEH) is a rare entity. However, several cases have been reported that occurred in various locations such as the trunk or extremities after traumatic events [1e4]. CEH related to osteoporotic insufficiency fracture has not been previously reported. We describe a unique case of CEH in the rectus abdominis muscle that resulted from an insufficiency fracture of the pubis. The patient was informed that data from the case would be submitted for publication, and she gave her consent.

Comparison of Atypical and Osteoporotic Femoral Shaft Fractures in the Elderly: A Multicenter Study

Background In atypical femoral fractures, owing to the high rates of complications and delayed healing that accompany the plate fixation, the most favorable treatment is intramedullary nailing. Although there is insufficient evidence, plate fixation is chosen due to anterolateral bowing of the femur. This study compared the bone healing time and rates of complications in atypical femoral shaft fractures and osteoporotic femoral shaft fractures. Methods We searched the medical records of 3 institutions in Japan for patients with femoral shaft fractures who visited between 1 January 2010 and 31 December 2015. We identified 65 patients and excluded 37 among these due to high-energy injuries or being younger than 65 years. Among the remaining patients, we identified 17 and 11 women with atypical (AFF group) and osteoporotic femoral shaft fractures (OP group), respectively. Results In surgical method, there were differences in intramedullary nailing (94.1% versus 27.2%) (p < 0.01). The mean bone healing time was 11.1 months versus 6.7 months in 2 groups (p < 0.01). Iatrogenic femoral fractures during intramedullary nail insertion were observed in both groups, and reoperation was only seen in atypical femoral fractures treated with a plate fixation, but there was no difference in the rate of complications (23.5% versus 9.1%). Conclusions In the atypical femoral fracture group, intramedullary nailing was more chosen, but the bone healing time was delayed and plate fixation cases needed reoperation. There was no significant difference in the rate of complications between the 2 groups.

Atraumatic aseptic necrosis of the talus with varus deformity of the knee in an elderly patient

A 78-year-old woman was hospitalized with right ankle pain. Chronic pain had been present for 5 years without any history of trauma. Radiographs revealed osteosclerosis and depression at the talus. The patient also had osteoarthritis in the bilateral knees with varus deformity. We performed total knee arthroplasty and obtained good leg alignment. The ankle was treated by bracing and observed. Thereafter, ankle pain gradually decreased. Five years after surgery, the patient has no pain in her ankle and can walk about 1000 m without bracing. Radiograph revealed that the difference in talar articular surface was smoothly remodelled.