Endoscopic anterior cruciate ligament reconstruction using a computer-assisted fluoroscopic navigation system

Background During anterior cruciate ligament (ACL) reconstruction, placement of the reconstructed ligament affects the clinical results. To accomplish accurate and reproducible placement of the tibial bone tunnel, we employed a fluoroscopic navigation system for endoscopic ACL reconstruction. In this study, preciseness of the tibial tunnel placement was evaluated, and the advantages and disadvantages of this navigation system for endoscopic ACL reconstruction are discussed. Methods Altogether, 16 knees of 16 patients who had undergone ACL reconstruction using this system (navi group) were evaluated regarding the positioning of the tibial tunnel against Blumensaat's line using X-p and the route of the graft by magnetic resonance imaging (MRI). Another 16 knees of 16 patients who underwent endoscopic ACL reconstruction without the navigation system were the controls (control group). Results At the 1-year follow-up, maximally extended lateral knee X-p revealed that the anterior edge of the tibial tunnel and Blumensaat's line were almost aligned and that roof impingement was avoided; the T2-weighted MR images showed that the graft was placed close to and parallel to the intercondylar roof in all the knees of the navi group. The ratio of the distance between Blumensaat's line and the anterior edge of the tibial tunnel at the level of the tibial plateau to the anteroposterior width in fully extended true lateral radiographs was 2.7% ± 3.4% in the navi group and 8.4% ± 7.4% in the control group. Conclusions The computer-assisted fluoroscopic navigation system improves accuracy and decreases dispersion of the tibial tunnel placement against Blumensaat's line in single-bundle ACL reconstruction. This innovative device renders the reconstruction procedure more reliable, eliminating the problem of skeletal variation among patients. However, the function of this navigation system for femoral tunnel placement is insufficient at present. Further refinement of the system is necessary, and the method of application requires improvement.     

Congenital quadricuspid aortic valve with tetralogy of Fallot and pulmonary atresia

We report the case of a 4-year-old girl who had quadricuspid aortic valve regurgitation with tetralogy of Fallot and pulmonary atresia. This combination is very uncommon. Aortic valve replacement was performed successfully due to aortic regurgitation which had progressed one year after the total repair. The dilated aortic annulus plus quadricuspid aortic valve may result in progressive aortic regurgitation for a short period.     

Distinct osteogenic mechanisms of bones of distinct origins

Mammalian bones have three distinct origins (paraxial mesoderm, lateral plate mesoderm, and neural crest) and undergo two different modes of formation (intra-membranous and endochondral). Bones derived from the paraxial mesoderm and lateral plate mesoderm mainly form through the endochondral process. During this process, hypertrophic chondrocytes play a vital role in inducing both osteogenesis and angiogenesis. One of the essential osteogenic factors secreted from hypertrophic chondrocytes is Indian hedgehog (Ihh). In contrast, bones derived from the neural crest mainly form through the intramembranous pro-cess and do not require Ihh. Thus, depending on their origin, bones have distinct signaling properties, which need to be considered in the research and application of bone biology.Presented at the 18th Annual Research Meeting of the Japanese Orthopaedic Association, Kitakyushu, Japan, October 17, 2003     

Plasma and tumor gastrin in patients with primary hyperparathyroidism

It is well known that primary hyperparathyroidism is often associated with peptic ulcer. The purpose of this study is to confirm the relationship between the gastrin-levels before and after parathyroidectomy in fourteen patients with primary hyperparathyroidism, and to determine the localization of gastrin in the surgically resected parathyroid tumor. The results obtained were as follows: 1) Three patients had peptic ulcer (gastric ulcer and duodenal ulcer), the incidence being 21%. 2) The basal serum gastrin levels were 123.0% +/- 68.1 pg/ml before operation and decreased to 90.2 +/- 44.5 pg/ml after operation. In the 3 patients with slightly elevated gastrin levels, the mean level before operation was 209.1 +/- 61.2 pg/ml. The gastrin level decreased to 116.4 +/- 62.0 pg/ml after operation. 3) Gastrin immunoreactivity was detected in 10 out of 14 tumors and its localization was at the periphery of tumor cells. From these results, we conclude that extragastric gastrin secretion from parathyroid tumors may be one of the cause of peptic ulcer in patients with primary hyperparathyroidism.     

Cutaneous eruption with or without ocular complications in patients with herpes zoster involving the trigeminal nerve

We examined 62 patients with acute herpes zoster involving the trigeminal nerve; 13 had eruptions only and 49 (51 eyes) had eruptions with ocular complications. Bilateral involvement was found in two patients. The frequency of the disease appeared to increase with age, and the disease was least active in November. Patients with eruptions only demonstrated affected areas along the first, second, and/or third divisions of the trigeminal nerve. Ocular complications occurred in patients who had eruptions along the first and/or second divisions of the nerve, and they were usually noted in patients with eruptions on the tip and one side of the node. The ocular complications and associated systemic conditions varied.     

Deficiency of insulin receptor substrate-1 impairs skeletal growth through early closure of epiphyseal cartilage.

Morphological analyses in and around the epiphyseal cartilage of mice deficient in insulin receptor substrate-1 (IRS-1) showed IRS-1 signaling to be important for skeletal growth by preventing early closure of the epiphyseal cartilage and maintaining the subsequent bone turnover at the primary spongiosa. Introduction: IRS-1 is an essential molecule for intracellular signaling by IGF-I and insulin, both of which are potent anabolic regulators of cartilage and bone metabolism. To clarify the role of IRS-1 signaling in the skeletal growth, morphological analyses were performed in and around the epiphyseal cartilage of mice deficient in IRS-1 (IRS-1(-/-)), whose limbs and trunk were 20-30% shorter than wildtype (WT) mice. MATERIALS AND METHODS: The epiphyseal cartilage and the primary spongiosa at proximal tibias of homozygous IRS-1(-/-) and WT male littermates were compared using histological, immunohistochemical, enzyme cytohistochemical, ultrastructural, and bone histomorphometrical analyses. RESULTS: In and around the WT epiphyseal cartilage, IRS-1 and insulin-like growth factor (IGF)-1 receptors were widely expressed, whereas IRS-2 was weakly localized in bone cells. Chronological observation revealed that height of the proliferative zone and the size of hypertrophic chondrocytes were decreased in WT mice as a function of age, and these decreases were accelerated in the IRS-1 (-/-) cartilage, whose findings at 12 weeks were similar to those of WT at 24 weeks. In the IRS-1(-/-) cartilage, proliferating chondrocytes with positive proliferating cell nuclear antigen (PCNA) or parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor immunostaining had almost disappeared by 12 weeks. Contrarily, TUNEL+ apoptotic cells were increased in the hypertrophic zone, at the bottom of which most of the chondrocytes were surrounded by the calcified matrix, suggesting the closure of the cartilage. In the primary spongiosa, bone volume, alkaline phosphatase (ALP)+ osteoblasts, TRACP+ osteoclasts, and the osteopontin-positive cement line were markedly decreased. Bone histomorphometrical parameters for both bone formation and resorption were significantly lower in IRS-1(-/-) mice, indicating the suppression of bone turnover. CONCLUSION: The IRS-1(-/-) epiphyseal cartilage exhibited insufficient proliferation of chondrocytes, calcification of hypertrophic chondrocytes, acceleration of apoptosis, and early closure of the growth plate. Thus, the data strongly suggest that IRS-1 signaling is important for the skeletal growth by preventing early closure of the epiphyseal cartilage and by maintaining the subsequent bone turnover at the primary spongiosa.     

Effect of nasal continuous positive airway pressure treatment on plasma adrenomedullin levels in patients with obstructive sleep apnea syndrome: roles of nocturnal hypoxia and oxidant stress.

Obstructive sleep apnea syndrome (OSAS) is recognized as one of the risk factors of hypertension and cardiovascular disorders. In the current study, we hypothesized that the hypoxic stress and oxidative stress caused by obstructive sleep apnea would increase circulating adrenomedullin (ADM) levels in untreated OSAS patients as compared to an age and body mass index (BMI)-matched control group and an age-matched, but normal-BMI control group. We further hypothesized that nasal continuous positive airway pressure (nCPAP) treatment may decrease OSAS-induced hypoxic stress, oxidative stress and ADM levels. To examine these hypotheses, we measured circulating ADM and reactive oxygen species (ROS) from leukocytes before and after nCPAP therapy in OSAS patients. The circulating levels of ADM and amount of ROS in untreated OSAS patients were significantly greater than those in the controls. No differences in ADM levels were found between the increased-BMI controls and normal-BMI controls. We observed that nCPAP treatment decreased sleep apneas, nocturnal oxyhemoglobin desaturation, the circulating ADM, and ROS production by leukocytes in OSAS patients. The ADM levels were associated with the magnitude of oxyhemoglobin desaturation rather than the number of sleep apneas. These observations suggest that nCPAP therapy could reduce OSAS-induced nocturnal hypoxemia, generation of ROS, and ADM in patients with OSAS.     

In vivo presynaptic and postsynaptic striatal dopamine functions in idiopathic normal pressure hydrocephalus.

Differentiation of impaired gait seen in idiopathic normal pressure hydrocephalus (iNPH) from parkinsonian gait is sometimes a great challenge and important for future medication in the clinical setting. To investigate dopaminergic contribution to its pathophysiology, two aspects of the trans-synaptic dopamine functions in the striatal region in eight iNPH patients na?ve to dopaminergic drugs were examined using positron emission tomography with a presynaptic marker [11C]CFT ([11C]2-beta-carbomethoxy-3beta-(4-fluorophenyl) tropane) that binds to dopamine transporter and a postsynaptic marker [11C]raclopride that binds to D2 receptor. Quantitative values of binding potentials (BPs) for [11C]CFT and [11C]raclopride were compared between patients and eight age-matched healthy subjects. The BPs and magnetic resonance imaging-based morphometric measures in iNPH were used for correlation analyses between the magnitude of binding of these in vivo markers and clinical severity of the patients. Analysis of variance showed significant reduction in [11C]raclopride binding in the putamen and nucleus accumbens (P<0.05, corrected for multiple comparison) and unchanged striatal [11C]CFT binding in iNPH. The dorsal putamen [11C]raclopride binding correlated negatively with gait severity (r=0.720, P<0.05), and the nucleus accumbens [11C]raclopride binding correlated positively with emotional recognition score (r=0.727, P<0.05) in the disease group. No significant relationship was observed between BPs and morphometric measures. The current result of the postsynaptic D2 receptor reduction along with preserved presynaptic activity in the nigrostriatal dopaminergic system reflects a pathophysiology of iNPH. Postsynaptic D2 receptor hypoactivity in the dorsal putamen may predict the severity of gait impairment in iNPH.