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Alagille syndrome is associated with decreased bile ducts, cardiac abnormalities, vertebral body fusion defects, and a typical facies. While regenerative nodules and hepatocellular carcinoma have been described in these patients, hepatic adenoma has not. Herein, we present a patient with Alagille syndrome caused by a mutation in NOTCH2 with a hepatic adenoma. The clinical, imaging, and histologic features are discussed.

Background Currently, cannulated pedicle screws have been widely used in minimal invasive or navigation techniques. However, the stress distribution and the strength of different core diameters of cannulated screw are not clear. This study aimed to investigate the mechanical strength of cannulated screws with different inner core diameter under various lumbar spine movements using finite element analysis. Results The results showed that the von-Mises stress of a cannulated screw was larger than that of a solid screw in all loading conditions, especially above 2 mm in cannulated core diameter. In lateral bending, extension, and flexion, the maximum von-Mises stress was found approximate to the proximal thread for all types of screws. In rotation condition, the maximum von-Mises stress was located at the middle of the screw. Additionally, the difference in stiffness of instrumented levels was not significant among four screws under the same loading condition. Conclusion Cannulated screws could provide enough stability for the vertebral body fusion comparing to solid screws. The diameter of cannulated core is suggested not to exceed 2.0 mm.

Selection of the operative procedure for treating multiple disc lesions is often difficult. We adopted anterior vertebral fusion (AVF) for the lowest double disc lesions, particularly for manual workers under 30 years of age. In these cases, over a period of 10 years after surgery stenosis of the canal at the L3-4 level has rarely been found although incomplate union of the L5/S disc space has sometimes been reported. In additoin, in cases of AVF for L4-5 disc lesions with L5-S disc degeneration, herniation of the L5-S has rarely occurred. These results meat that since 1986 we have carried out AVF for L4-5 and anterior discectomy without fusion for L5-S. We clinically evaluated 36 cases all with a post-operative follow-up of at ledst 12 months.Results are as follows:(1) Radiological Findings:1) Narrowing of L5-S disc space and posterior displacement of L5 were found relatively early after surgery2) The range of motion in L5-S disc space tended to decrease after 2 years post-operatively, but its ROM was greater than other disc spaces.(2) Clinical findings:1) Clinical improcement was noted shortly after operation.2) Improvement in ADL, as evidenced by improvement in the range of movement and the ability to life heavy things, was mostly found withinl-2 years after operation.

Case ReportsA 61-year-old man with left lumbar pain and left lower limb pain was pointed out to have an abnormal shadow in the spinal canal on CT-scan.Simple X-P view in the lumbal spine revealed vacuum phenome non in L3-4 intervertebral disc.Myelography revealed the defect of the left L4 root at the supe rior aspect of the L4 vertebral body.Plain-CT revealed low density lesion in the spinal canal at the same level.Discography and CTD revealed the continuance between interv ertebral disc and cystic tissue.We confirmed cystic tissue surrouded by the thick capsule and the presence of the gas collection in it at the operation.We did disectomy and vertebral body fusion via the posterior approach to prevent a relapse.The patient was in good condition after the operation.

Anterior cervical diskectomy in cervical disk lesions with vertebral body fusion using polymethyl methacrylate (Palacos) for fixation gives excellent results in most of our patients. We are now able to report on 618 patients operated on during the last 16 years. During the first few years we used a bone graft for fixation, but from 1968 on we preferred polymethyl methacrylate (Palacos). The results were very favorable, but we also observed a specific complication of these operations that may cause the patient pain and difficulties.

Two cases of the severe fracture-dislocation of the cervical spine with tetraplegia have been treated successfully with a new technique. This technique consists of anterior vertebral body fusion with a tibia span added to the Cloward's method. This procedure permitted substantial removal of ruptured disks and bone fragments, effectivelly strengthened the spine weakened by fracture, and also enabled early start to a postoperative rehabilitation program. It seems that fracture-dislocation of the cervical spine should be treated operatively as early as possible.

A brief description is given of the operative technic and the instruments used in the new operation of vertebral body fusion for ruptured cervical discs by an anterior approach. In the past two years this operation has been used on eighty-four patients from whom one or more cervical discs were removed and the vertebral bodies fused. Fusion occurred in eighty-one patients with complete relief of pain in the neck, shoulder and upper extremities.

Oryzias latipes is increasingly used as a model in biomedical skeletal research. The standard approach is to generate genetic variants with particular skeletal phenotypes which resemble skeletal diseases in humans. The proper diagnosis of skeletal variation is key for this type of research. However, even laboratory rearing conditions can alter skeletal phenotypes. The subject of this study is the link between skeletal phenotypes and rearing conditions. Thus, wildtype medaka were reared from hatching to an early juvenile stage at low (LD: 5 individuals/L), medium (MD: 15 individuals/L), and high (HD: 45 individuals/L) densities. The objectives of the study are: (I) provide a comprehensive overview of the postcranial skeletal elements in medaka; (II) evaluate the effects of rearing density on specific meristic counts and on the variability in type and incidence of skeletal anomalies; (III) define the best laboratory settings to obtain a skeletal reference for a sound evaluation of future experimental conditions; (IV) contribute to elucidating the structural and cellular changes related to the onset of skeletal anomalies. The results from this study reveal that rearing densities greater than 5 medaka/L reduce the animals’ growth. This reduction is related to decreased mineralization of dermal (fin rays) and perichondral (fin supporting elements) bone. Furthermore, high density increases anomalies affecting the caudal fin endoskeleton and dermal rays, and the preural vertebral centra. A series of static observations on Alizarin red S whole mount-stained preural fusions provide insights into the etiology of centra fusion. The fusion of preural centra involves the ectopic formation of bony bridges over the intact intervertebral ligament. An apparent consequence is the degradation of the intervertebral ligaments and the remodeling and reshaping of the fused vertebral centra into a biconoid-shaped centrum. From this study it can be concluded that it is paramount to take into account the rearing conditions, natural variability, skeletal phenotypic plasticity, and the genetic background along with species-specific peculiarities when screening for skeletal phenotypes of mutant or wildtype medaka.

In a series of 91 patients under 20 years of age with lytic spondylolisthesis treated by different operations, 66 (73%) showed a displacement of more than 30 per cent at admission. If the displacement exceeds 30 per cent, it often progresses to a subtotal olisthesis. Spinal fusion should be performed before the displacement exceeds a third of the length of the vertebra. A posterior fusion with two massive tibial grafts was carried out in 78 patients (87.5%). Concurrent with fusion laminectomy was performed in 18 patients. Anterior vertebral body fusion was performed in 3 patients and posterolateral fusion in 10, in 4 of these as a secondary operation. Laminectomy alone was carried out in 4 patients, 3 of these having a total olisthesis. Laminectomy without fusion should be performed only in exceptional cases in young patients. Non-union or uncertain union after the primary operations occurred in 17 cases (19.5%); 15 reoperations were performed in 13 patients. The degree of displacement at operation did not influence the results. A progression of displacement despite dorsal fusion was observed in 14 patients. The final results of operative treatment were: good in 55 patients (60.4%); satisfactory in 23 (24.1%); unsatisfactory in 13 (15.5%). Posterolateral fusion seems to be preferable to posterior fusion.

Fig. 10 Halftone drawings, demonstrating a transvertebral grafting procedure on the anterior aspect of the lumbosacral joint. The lower right-hand figure shows insertion of full -thickness iliac graft, ‘‘coin’’ type. Two such grafts per level are preferred. If the most superficial (ventral) graft cannot be countersunk to more than one-eighth inch below the vertebral margin, screw fixation, oblique at a 45-degree angle through graft and into sacral body is recommended. (Reprinted with permission and Lippincott Williams & Wilkins, from Harmon, PH. Anterior excision and vertebral body fusion operation for intervertebral disk syndromes of the lower lumbar spine: three to five year results in 244 cases. Clin Orthop Relat Res. 1963;26:107–127.) Fig. 11 An alternative technique of preparation of graft bed and insertion of 2 rectangular grafts illustrated for the L-4 level: (A) incision in the anterior ligament; (B) preparation of graft bed; (C) completed grafting procedure. (Reprinted with permission and Lippincott Williams & Wilkins, from Harmon, PH. Anterior excision and vertebral body fusion operation for intervertebral disk syndromes of the lower lumbar spine: three to five year results in 244 cases. Clin Orthop Relat Res. 1963;26:107–127.) Published online: 31 March 2012 The Association of Bone and Joint Surgeons1 2012

Dietary phosphorus (P) is essential for bone mineralisation in vertebrates. P deficiency can cause growth retardation, osteomalacia and bone deformities, both in teleosts and in mammals. Conversely, excess P supply can trigger soft tissue calcification and bone hypermineralisation. This study uses a wide range of complementary techniques (X-rays, histology, TEM, synchrotron X-ray tomographic microscopy, nanoindentation) to describe in detail the effects of dietary P on the zebrafish skeleton, after two months of administering three different diets: 0.5% (low P, LP), 1.0% (regular P, RP), and 1.5% (high P, HP) total P content. LP zebrafish display growth retardation and hypomineralised bones, albeit without deformities. LP zebrafish increase production of non-mineralised bone matrix, and osteoblasts have enlarged endoplasmic reticulum cisternae, indicative for increased collagen synthesis. The HP diet promotes growth, high mineralisation, and stiffness but causes vertebral centra fusions. Structure and arrangement of bone matrix collagen fibres are not influenced by dietary P in all three groups. In conclusion, low dietary P content stimulates the formation of non-mineralised bone without inducing malformations. This indicates that bone formation and mineralisation are uncoupled. In contrast, high dietary P content promotes mineralisation and vertebral body fusions. This new zebrafish model is a useful tool to understand the mechanisms underlying osteomalacia and abnormal mineralisation, due to underlying variations in dietary P levels.