Hydroxyapatite-coating of pedicle screws improves resistance against pull-out force in the osteoporotic canine lumbar spine model: a pilot study.

BACKGROUND CONTEXT: In patients with spinal osteoporosis, the early achievement and maintenance of a biological bond between the pedicle screw and bone is important to avoid screw loosening complications. There are few reports of in vivo investigations involving biomechanical and histological evaluations in the osteoporotic spine. PURPOSE: To evaluate the effect of hydroxyapatite (HA)-coating on the pedicle screw in the osteoporotic lumbar spine and to investigate the relationship between resistance against the screw pull-out force and bone mineral density (BMD) of the vertebral body. STUDY DESIGN/SETTING: Mechanical and pathological investigations in the lumbar spine. METHODS: Two 24-month-old female beagle dogs were fed a calcium-free dog chow for 6 months after ovariectomy (OVX). BMD (in g/cm2) was measured by dual energy X-ray absorptiometry at pre-OVX and 6 months after OVX. Pedicle screws were placed from L1 to L6 at 6 months after OVX. Twenty-four pure titanium cortical screws (Synthes, #401-114) were used as pedicle screws (Ti-PS). Of these, 12 screws had HA-coating (HA-PS). The HA-PS screws were inserted into the right pedicles and the Ti-PS were inserted into the left pedicles. Ten days after this procedure, the lumbar spines were removed en bloc for screw pull-out testing and histological evaluation. RESULTS: The mean BMD value of the lumbar vertebrae 6 months after the OVX was 0.549+/-0.087 g/cm2, which was significantly less than the pre-OVX mean BMD of 0.603+/-0.092 g/cm2 (p < 0.001). The mean resistance against the pull-out force for the HA-PS was significantly greater at 165.6+/-26.5N than in the Ti-PS (103.1+/-30.2N, p < .001). The histological sections in the HA-PS clearly revealed new bone bonding with the apatite coating but only fibrous tissue bonding in the Ti-PS. CONCLUSIONS: The results of this study showed that the resistance to the pull-out force of HA-PS is 1.6 times that of Ti-PS. Furthermore, HA-PS has superior biological bonding to the surrounding bone, as early as 10 days after surgery in this osteoporotic spine model. Thus, in patients with osteoporosis, coating of the pedicle screw with HA may provide better stability and bonding between the pedicle screw and bone in the early postoperative period.     

Successful Norwood operation for single left ventricle associated with severe subaortic stenosis, coarctation of aorta and hypoplastic aorta]

A 4 month-old boy who had double-inlet left ventricle, severe subaortic stenosis, hypoplastic ascending aorta and coarctation of the aorta revealed severe respiratory failure. An urgent Norwood operation was done. The procedure consisted of enlargement of the ascending aorta and main pulmonary artery and a systemic-pulmonary shunt using 5 mm PTFE tube. Postoperative course was uneventful.     

Statistical analysis of the prostatic cancer patients detected from 1985 to 1989 in and around Gunma prefecture]

Prostatic cancer is one of the most common malignant tumors in the field of urology. The number of patients is increasing rapidly and its importance as a mortal disease is gathering attention. In 1985, we organized a registration system for prostatic cancer patients found in and around Gunma prefecture. In this study, we analyzed the clinical characteristics of the 730 patients registered from 1985 to 1989. The results were as follows. Mean age was 74.0 years old and the number of the patients was the greatest in the eighth decade. Voiding disturbance was the most common chief complaint, followed by pollakisuria, gross hematuria and miction pain. Stage and grade distribution were as follows. Stage A 16.2%, B 21.1%, C 17.0%, D 45.7%, well differentiated 27.4%, moderately differentiated 48.2% and poorly differentiated 24.5%, respectively. A statistically significant relationship between stage and grade was observed. Bone was the most common metastatic site. The highest incidence of bone metastasis was in lumbar vertebra, followed by ribs, ilium, thoracic vertebra and ischium. The value of PAP, ALP and ESR tended to be higher in high stage patients, and that of Hb was lower. Fifty two patients were detected by mass screening. Most of these patients were in an early stage. Most of the patients were treated by hormonal therapy. LH-RH agonists constituted 39.2% of the cases given hormonal therapy.     

The effects of long-term intake of a low concentration of sodium fluoride on bone loss in the growing senescence-accelerated mouse (SAM-P/6)]

The long-term effects of low concentrations of sodium fluoride (0, 1 and 5 mg/l) in drinking water on bone metabolism were examined in the growing senescence accelerated mouse (SAM-P/6) as a spontaneous experimental model of senile osteoporosis. In 4 and 8 months of age respectively, there were almost no differences in body weight, and serum calcium, phosphorus and alkaline phosphatase levels between controls and fluoride groups. Calcium contents per dry weight of femoral bone were higher in fluoride groups than in controls. The bone mass of the trabecular was not affected by the low-concentration sodium fluoride intake. However, sodium fluoride decreased the rate of bone mass loss associated with aging in the cortical bone in SAM-P/6 compared with the control. The results of this study suggest that, in growing SAM-P/6 mice, a long-term low-concentration sodium fluoride intake affects the skeletal metabolism.     

Measurement of the zeta potential of human platelets by the use of laser-light scattering.

An instrument was developed to detect the shift in scattering of laser light that occurs when particles in suspension move in a chamber with an electrical load. The instrument measures the zeta potential of particles. We applied the instrument to study human blood cells. Platelet-rich plasma was used because of the stability of the suspension, without the sedimentation or autoaggregation that is often seen with red or white blood cells. The reproducibility of the measurements was satisfactory when there were enough platelets in the suspension. Platelets from healthy controls (n = 136) had a potential of -14.20 +/- 1.64 mV at the detection angle of 17.1 degrees. Platelets from patients with essential thrombocytosis (n = 16) or polycythemia vera (n = 8) had higher potentials than the healthy controls.     

Radical correction of paracardiac type IIb of total anomalous pulmonary venous connection using pedicled flaps of right atrium and atrial septum

Surgical results of total anomalous pulmonary venous connection (TAPVC) has been improved in recent years, however, late development of pulmonary venous obstruction was our concern in its total correction in early infancy. In the cardiac type of TAPVC, in which the pulmonary veins were connected to the right lateral wall, prosthetic patch is conventionally used in diversion of pulmonary venous flow into left atrium. It seemed favorable to repair this subset without using prosthesis. A 3-month-old female with TAPVCIIb according to Darling's classification underwent total correction on September 22th, 1988. Two pedicled flaps were developed using the right atrial wall and the atrial septum to create a pulmonary venous channel to divert arterial blood into left atrium and absorbable sutures were used throughout. Right atrium was entered through a vertical incision in its body and all the pulmonary veins were found in a recess in the lateral wall of the right atrium. Atrial septal defect in the cranial aspect of the fossa ovalis was enlarged by cutting the primum tissue along the right limbus and its caudal margin so as to form a pedicled flap attached to the left limbic tissue. Then the flap was sutured along the limbus to create a roof of the fossa ovalis. The second flap was made in the middle of the lateral atrial wall and was used to create a tunnel from the recess to the atrial septal defect. The defect in the right atrial wall was closed directly and no prosthetic patch was used. Postoperative course was uneventful and echocardiogram showed wide pulmonary venous channel draining into the left atrium.     

Bilateral symmetric tonic posturing suggesting propagation to the supplementary motor area in a patient with precuneate cortical dysplasia.

We report a patient manifesting seizures with bilateral symmetric tonic posturing, which were markedly reduced after resection of the left precuneus. A 16-year-old man had sudden onset, complex partial seizures with bilateral symmetric tonic posturing since the age of eight years. Magnetic resonance fluid-attenuated inversion-recovery imaging revealed a hyperintense lesion in left precuneus. In almost all focal seizures recorded during an invasive EEG evaluation, ictal onset was detected from the inferomesial aspect of the lesion, but fast paroxysmal discharges from the ipsilateral supplementary motor area (SMA) were observed just before the clinical onset. After surgical excision of the EEG onset zone, including the lesion, seizure frequency was markedly (> 95%) reduced. By the 20th month after surgery, there were only brief nocturnal seizures involving slight elevation of both shoulders and slight abduction of both arms, with preservation of consciousness occurring once every few days. Invasive EEG findings and surgical outcome suggested that the epileptic activity originating from the epileptogenic zone may have propagated to the symptomatogenic zone including mainly the ipsilateral SMA. In summary, we report an interesting case of bilateral symmetric tonic posturing suggesting propagation to the SMA. MRI and invasive EEG confirmed the epileptogenic focus as a precuneate cortical dysplasia lesion.[Published with video sequences].     

Evaluation of blood flow patterns of true and false lumens in dissecting aneurysms using MR phase-contrast techniques

The magnetic resonance phase-contrast technique for the measurement of flow velocity and volume in true and false lumens was studied in six patients with chronic dissecting aneurysms. Phase-contrast images were obtained at a level perpendicular to the dissecting aneurysms of the descending aorta. As the maximum diameter of aneurysms increased, the ratio of the cross-sectional area of the false to the true lumen increased and the peak average velocity in the true lumen during systole was decreased. This technique proved invaluable for determining prognosis and operability for this condition.