Morphology of the inferior border of the mandible: correct relation between the lowest position of the outer and inner contours of the cortex for a successful split.

For a sagittal split ramus osteotomy to be secure, the relation between the outer and inner contours of the cortex at the inferior border of the mandible is critical. The lowest point of the outer contour is not always immediately below that of the inner contour, and the former is placed more lingually than the latter in about a third of all cases. This tendency is much more noticeable in skeletal class I and II malocclusions than class III. It is therefore important to examine the lowest point of the inferior border in every case, and to carry the inferior part of the buccal cut on to the lingual side if necessary.

Pathophysiological role of endothelin in ectopic ossification of human spinal ligaments induced by mechanical stress.

Ossification of the posterior longitudinal ligament (OPLL) of the spine is characterized by progressive ectopic bone formation in the spinal ligament. To identify the genes related to ossification affected by mechanical stress during OPLL, analyses using cDNA microarray were carried out using cultured human spinal ligament cells that had been subjected to uniaxial cyclic stretching. Samples were obtained from a total of 14 patients: seven cervical or thoracic OPLL patients and seven control patients. Spinal ligament cells derived from tissues of OPLL (OPLL cells) and control (non-OPLL cells) patients were subjected to uniaxial sinusoidal cyclic stretching (0.5 Hz, 20% stretch) for various time periods (0-9 hours). cDNA microarrays revealed that ranges of distribution of both up- and downregulated genes evoked by cyclic stretching were significantly wider in OPLL cells than in non-OPLL cells. Increases in the mRNA expression of endothelin-1 (ET-1) as well as various marker genes related to ossification were also observed. mRNA expression of ET-1 and alkaline phosphatase was increased by mechanical stress in a time-dependent manner, while addition of ET-1 to static cultures of OPLL cells increased mRNA expression of alkaline phosphatase in a dose-dependent manner. During 9 hours of cyclic stretching, ET-1 release increased to about sixfold the amount observed in nonstretched cells. In non-OPLL cells, neither cyclic stretching nor ET-1 induced any increase in alkaline phosphatase expression. These results suggest that mechanical stress promotes the progression of ossification in OPLL cells through autocrine and/or paracrine mechanisms of ET-1.

Uni-axial cyclic stretch induces Cbfa1 expression in spinal ligament cells derived from patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To clarify this mechanism, we investigated the effects of in vitro cyclic stretch (120% peak to peak, at 0.5 Hz) on cultured spinal ligament cells derived from OPLL (OPLL cells) and non-OPLL (non-OPLL cells) patients. The mRNA expressions of Cbfa1 (an osteoblast-specific transcription factor), type I collagen, alkaline phosphatase (ALP), osteocalcin and integrin beta1 (a mechanotransducer) were increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. The effects of cyclic stretch on the spinal ligament tissues derived from OPLL and non-OPLL patients were also analyzed by immunohistochemistry using an antibody against Cbfa1. The expression of Cbfa1 was increased by cyclic stretch at the center of the spinal ligament tissues of OPLL patients, whereas no change was observed in the tissues of non-OPLL patients. Furthermore, U0126, a specific inhibitor of MAPK kinase (MEK), suppressed the stretch-induced mRNA expressions of Cbfa1, ALP and type I collagen in OPLL cells. These results suggest that in OPLL cells, mechanical stress is converted by integrin beta1 into intracellular signaling and that Cbfa1 is activated through the MAP kinase pathway. Therefore, we propose that mechanical stress plays a key role in the progression of OPLL through an increase in Cbfa1 expression.

Uniaxial cyclic stretch induces osteogenic differentiation and synthesis of bone morphogenetic proteins of spinal ligament cells derived from patients with ossification of the posterior longitudinal ligaments.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To elucidate this mechanism, we investigated the effects of in vitro sinusoidal cyclic stretch (120% peak to peak, at 1 Hz) on cultured spinal ligament cells derived from OPLL and non-OPLL patients. The mRNA expressions of alkaline phosphatase (ALP), osteopontin, bone morphogenetic protein (BMP)-2, BMP-4, and BMP receptors as well as ALP activity in cell layers and production of BMPs into the conditioned medium were significantly increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. A stretch-activated Ca(2+) channel blocker, Gd(3+), the voltage-dependent L-type Ca(2+) channel blockers diltiazem and nifedipine, and Ca(2+)-free medium suppressed stretch-induced ALP activity, which suggests a role of Ca(2+) influx in the signal transduction of mechanical stress to the osteogenic response of OPLL cells. Our study provides first evidences that mechanical stress plays a key role in the progression of OPLL through the induction of osteogenic differentiation in spinal ligament cells and the promotion of the autocrine/paracrine mechanism of BMPs in this lesion.

Treatment of soft tissue injuries to the dorsum of the metacarpophalangeal joint (Boxer's knuckle).

We retrospectively reviewed the surgical treatment for 16 cases of traumatic soft tissue injury to the metacarpophalangeal joint (Boxer's knuckle). A history of trauma was present in all cases and there was an associated extensor tendon dislocation in seven cases. Eight cases were initially treated conservatively, but their symptoms persisted. Intraoperative findings included rupture of the extensor hood or joint capsule in all cases. Surgical closure of the rupture of the joint capsule resulted in a successful outcome in all cases. We consider that conservative treatment of this injury may not be effective when the joint capsule of the metacarpophalangeal joint is ruptured. We recommend arthrography of the metacarpophalangeal joint to assist in the decision as to whether to proceed with surgical or conservative treatment.

Ipsilateral pedicle vascularized fibula grafts for reconstruction of tibial defects and non-unions.

Between October 1983 and August 1998, 31 patients with non-union or bone defect of the tibia have undergone 32 vascularized fibula transfers to reconstruct lower legs. Of these 32 vascularized fibula transfers, there were 19 pedicle transfers from the ipsilateral leg. There were 17 males and two females. The average patient age was 53 (21 to 84) years old. All patients achieved good bone reconstruction. All patients are currently able to walk without a brace, except for one. As to major complications, three of these 19 had delayed union, with only one postoperative fracture. In the cases with delayed union or fractured grafted fibulas, the periods to walking without a brace were longer than in the cases without such major complications. From the results, the ipsilateral pedicle vascularized fibula graft appears to be a useful option for reconstruction of tibial defects.

Combining free vascularized fibula graft and the Ilizarov external fixator: recent approaches to congenital pseudarthrosis of the tibia.

The present study compares a recent approach for congenital pseudarthrosis of the tibia, combining a free vascularized fibula graft and an Ilizarov external fixator. Between 1984 and 1993, seven vascularized fibula grafts were performed. In the first six cases, casts or unilateral external fixators were applied, and five of these cases were complicated by fractures of the graft, necessitating secondary procedures or long-term immobilization. The mean follow-up was 12.1 years. Five patients can now walk unassisted, and one uses a brace only outdoors. On average, a brace was required for 18 months. In the recent Ilizarov external fixator case, the fixator was removed after 4 months and a brace was unnecessary at 10 months. There was no leg-length discrepancy, severe ankle deformity, or fracture of the grafted fibula 7 years postoperatively. Combining a free vascularized fibula graft with an Ilizarov external fixator is recommended for this condition.

One-bone forearm formation using vascularized fibula graft for massive bone defect of the forearm with infection: case report.

Massive long-bone defects of greater than 6 cm are difficult to treat with conventional bone grafts, and other methods are sometimes recommended, such as vascularized bone grafts or bone transport using the Ilizarov external fixator. The combination of local infection with a massive bone defect exacerbates the problem, and provides an even more negative prognosis. The authors treated a large bone defect of the forearm with local infection, using a one-bone forearm formation with a large vascularized fibula graft. They attached an adequate amount of muscle fascia to the vascularized fibula, which was useful not only for coverage of the skin defect, but also for treatment of the local infection. Twenty months after surgery, elbow and hand functions were maintained, and the patient had no disturbance of hand function in daily activities, although rotation of the forearm was sacrificed.

Establishment of an optimized set of 406 microsatellite markers covering the whole genome for the Japanese population.

Microsatellites, an essential tool for genetic linkage analyses, are selected in genetic studies on the basis of both informativeness and their positions with respect to one another on the genetic map. In order to establish a microsatellite marker set useful for linkage studies in the Japanese population, we first genotyped 64 unrelated Japanese subjects, using 400 microsatellite markers from a commercially available set (ABI PRISM Linkage Mapping Set-MD10) and then determined the allelic frequencies and heterozygosities for these marker loci in the population. In order to optimize the set, we replaced 41 markers having a heterozygosity lower than 0.6 with as many informative markers in the corresponding loci, and newly added six markers in the set to minimize the several gaps found at intervals of over 20 cM. We finally established a set comprising 406 microsatellites with average intervals of 9cM (maximum, 17 cM) and minimum heterozygosities of over 0.6 (mean, 0.76). All data generated in this study, including the specific polymerase chain reaction (PCR) primer sequences of the newly added markers, are freely available to all researchers at our web site. The genetic tool established here should facilitate genetic linkage studies of various hereditary diseases, especially in the Japanese.

Gender-specific haplotype association of collagen alpha2 (XI) gene in ossification of the posterior longitudinal ligament of the spine.

Among Japanese, ossification of the posterior longitudinal ligament of the spine (OPLL) is a leading cause of myelopathy, showing ectopic bone formation in the paravertebral ligament. We have provided genetic evidence that the collagen alpha2 (XI) (COL11A2) locus of chromosome 6 constitutes susceptibility for OPLL. Five distinct single nucleotide polymorphisms (SNPs), identified in COL11A2, were combined to construct possible haplotypes by the use of a maximum likelihood program. Estimated haplotype frequency was compared in OPLL patients and non-OPLL controls. We report a gender-specific association of the COL11AA2 haplotvpe with OPLL. The frequency of the most commonly observed haplotype was significantly higher in male patients (P = 0.0003) compared with controls, but not in female patients (P = 0.21). OPLL is predominantly observed in males. with a prevalence ratio of 2:1, and our gender-specific associations indicate that genetic factors involving COL11A2 play a specific role in the etiology of OPLL exclusively in males.

Structural varieties of small proteoglycans in human spinal ligament.

Three types of small proteoglycan were purified from human spinal ligaments by ultracentrifugation, ion-exchange chromatography, gel-chromatography, and hydrophobic chromatography. Two of them were identified as decorin and biglycan, and the other was thought to be a decorin-subtype. Molecular sizes of decorin and decorin-subtype were both 85 kDa, and that of biglycan was 200 kDa. N-Terminal amino acid sequence of decorin-subtype corresponded with that of decorin, although it was different from decorin in terms of composition of amino acids and glycosaminoglycan chains, and reactivity with anti-human decorin antibody. The ratios of chondroitin sulfate to dermatan sulfate contained in the three proteoglycans were different, and the location of that in glycosaminoglycan chains was also thought to be different. It was demonstrated that three types of proteoglycan which are structurally different are present in extracellular matrix.

Anterior cervical fusion using porous hydroxyapatite ceramics for cervical disc herniation. a two-year follow-up.

BACKGROUND CONTEXT: The Smith-Robinson Method (SR), which employs autogenous bone, is the current standard for anterior cervical fusion (AF) surgery. However, autogenous bone has graft-related complications and morbidity, and harvesting it increases trauma and risk to the patient. The use of hydroxyapatite ceramic (HAP) inserts may provide a superior alternative. PURPOSE: To determine the efficacy of using HAP in AF. STUDY DESIGN/SETTING: A retrospective study of patients who had AF surgery with wide decompression and porous HAP inserts used to treat cervical disc herniation (CHD). PATIENT SAMPLE: We evaluated 36 patients who had single-level AF using HAP for CHD, without internal fixations, clinically and radiographically with a minimum follow-up of 2 years. There were 25 men and 11 women, with an average age of 49 years (age range, 24-78 years). Preoperative diagnosis included 25 cases with myelopathy and 11 cases with radiculopathy. OUTCOME MEASURES: We established four grades to classify the degree of bony fusion between the HAP and vertebra, based on any motion at the fused segment, any radiolucent zones (RZ) between vertebral bodies and the grafted HAP, and anterior or posterior bone formations on grafted HAPs. We evaluated the severity of myelopathy by applying the Japan Orthopaedic Association (JOA) scoring system. We evaluated the surgical outcome of the myelopathy patients using the Hirabayashi recovery rating, and for the radiculopathy patients, we used the Herkowitz criteria. METHODS: We retrospectively reviewed the radiographic and clinical records of all 36 patients from surgery up to periods ranging from 2 to 7 years after surgery, with the average period of follow-up being 4.5 years. We systematically classified the degree of bony fusion into four grades ranging from Grade 1 nonunion to Grade 4 complete union. RESULTS: None of the subjects showed Grades 1 and 2 fusion. Eleven percent of the cases showed Grade 3 and 89% showed Grade 4. Loss of height of the fused segment was observed in 29 cases with an average of 1.6 mm. A decrease of lordotic angle of the fused segment was observed in six cases with an average of 2.3 degrees. Four cases revealed cracked HAP inserts but achieved Grade 4 bone fusion. There was no evidence of collapse or displacement of HAPs. The results of the 11 radiculopathy patients were excellent in 10 cases and good in the remaining case. The recovery rate of the 25 myelopathy patients was 73.0%. CONCLUSIONS: Our method of anterior cervical fusion surgery using porous HAP inserted into resected end plates, combined with a wide decompression procedure, had clinical and radiographic results so satisfactory that we conclude that it can effectively replace the use of autogenous bone for treating cervical disc herniation.

Vascularized free flaps for reconstruction after resection of congenital arteriovenous malformations of the hand.

Between 1981 and 1996, the authors performed reconstructions with vascularized free flaps in four patients with congenital arteriovenous malformations of the hand. This series included one man and three women, whose ages at the time of surgery ranged from 20 to 57 years, with an average of 41 years. All were categorized as fast-flow type B malformations. The locations of the arteriovenous malformations were the thumb only, thumb to palm, index to palm, and thumb and index to palm. In all cases, free vascularized flaps (two dorsalis pedis, one wrap-around, and one peroneal) were utilized to replace the resected abnormal skin lesions. Follow-up ranged from 1 year to 18 years and 9 months, with an average of 7 years. All flaps survived with no complications, and all patients were relieved of their preoperative symptoms. One patient unfortunately committed suicide for unknown reasons. The authors recommend that complete resection be carried out whenever possible. When skin is involved, repair should be carried out with a free flap. Based on the good results achieved in the case followed-up for over 18 years, vascularized free flaps proved very useful for the treatment of arteriovenous malformations.

Bone mineral density and osteo sono assessment index in adolescents.

The standard value for bone mineral density in the distal radius (R-BMD) and the osteo sono assessment index (OSI) in the os calcaneus for each sex and age in teenagers have not yet been fully reported. The R-BMD and OSI of junior and senior high school students were measured by dual energy X-ray absorptiometry (DEXA) or by a quantitative ultrasound technique. Subjects measured by DEXA included 635 junior and senior high school students (274 males and 361 females, aged 12-17 years). Ultrasound measurements were made for 2878 subjects (1733 males, 1145 females, aged 12-18 years). All subjects filled out questionnaires about their past history, family history, past and present eating habits, sports activities, and for females, the presence of menses, regularity of menses, and so on. The R-BMD in 15- to 17-year-old males was significantly higher than that in females. The R-BMD rate of increase in males was almost linear; the rate of increase in females was significantly highest from ages 12 to 13, after which R-BMD increased gradually. The OSI in 15- to 18-year-old males was significantly higher than that in females. The OSI rate of increase in males was almost linear from ages 12 to 17. The OSI in females, except in 14-year-olds, was roughly equal at each age. The OSI was significantly higher in those who regularly participated in sports, either currently or in the past. It was significantly higher in those who previously or currently consumed milk on a daily basis compared with those who had consumed little or no milk. To prevent osteoporosis, increasing peak bone mass is very important. Adequate calcium intake from dairy products which are rich in calcium and absorbed easily, and exercise in adolescence, are expected to result in increased bone formation and increased OSI.

Severely displaced scaphoid fracture treated by arthroscopic assisted reduction and osteosynthesis.

The severely displaced scaphoid fracture, when combined with a scapholunate dissociation, is a very rare condition that commonly is treated by open surgery. The authors present a case treated by arthroscopic-assisted closed reduction, using percutaneous pinning for the scapholunate dissociation and a Herbert/Whipple screw insertion for the scaphoid fracture. The patient was able to return to work four months after surgery. At twenty-seven months after surgery, both the patient's grip power and range of motion in the wrist were acceptable. The authors recommend this procedure as a minimally invasive operation.

Experimental study on vascularized island pedicle bone graft: bony fusion between the graft and the recipient floor.

To evaluate the process of bony fusion between the recipient floor and the bone graft, where a muscle sleeve has been interposed, an experimental model for a vascularized island pedicle bone graft was prepared using rats. The proximal two thirds of the tibia pedicled with the popliteal artery and vein was collected to be used as a vascularized bone. This was onlay grafted to the femur of the same limb in such a manner that the muscle sleeve was interposed between the bone graft and the recipient floor. The animals subjected to this procedure were designated as the vascularized island pedicle bone graft group (hereafter called group V, n = 32). In another group, vascular pedicles were interrupted by ligation and the animals were subjected to nonvascularized bone graft (hereafter called group N, n = 32). In the third group, an appropriate amount of bone chips was transplanted throughout the length of the grafted floor; then the animals were subjected to additional vascularized island pedicle bone graft (hereafter called group B, n = 13). In groups V and B, the vascularized bone graft formed new bone at the site where the bone graft faced the recipient floor 6 weeks after surgery. Hypertrophy of the bone graft was noted. Bony fusion at the section where a muscle sleeve had been interposed was recognized only in group B. Chondrocytes were found around the free bone graft, suggesting chondrocyte participation in osteogenesis. In group N, the bone graft had been absorbed and no bony fusion was recognized between the bone graft and recipient floor in any of the samples. These findings imply that it is important to minimize the size of the muscle sleeve attached to the vascularized island pedicle bone graft and add free bone chips around the grafted bone to assure bony fusion between a vascularized bone graft and the recipient floor in clinical practice.

Human retinoic X receptor beta: complete genomic sequence and mutation search for ossification of posterior longitudinal ligament of the spine.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the ligament. OPLL is a very common disorder, in fact it constitutes the leading cause of myelopathy among Japanese. In the previous report, we provided the genetic linkage evidence that the genetic susceptibility of OPLL mapped to HLA complex of chromosome 6. As a candidate gene approach, retinoic X receptor beta (RXR beta), assigned to chromosome 6p21.3 adjacent to HLA class II, was analyzed for a possible causality. To start screening for the molecular variants of RXR beta in OPLL subjects, we first obtained P1 phage genomic clones containing the entire human RXR beta and elucidated the genomic organization of the gene. The human RXR beta is composed of 10 exons spanning over 6.2 kb of genomic DNA. Sequence analysis of the promoter region revealed a GC-rich sequence without TATA motif. We have identified three distinct molecular variants, one was in exon 10 and two were in the intergenic region between RXR beta and collagen 11A2 (COL11A2). Two variants in the intergenic region, 3' end + 140 and 3' end + 561, exhibit statistically significant associations with OPLL in case-control study (p = 0.0028 for 3' end + 140 and p = 0.034 for 3' end + 561). These results indicate that the genetic causality of OPLL lies within or close to the RXR beta/COL11A2 locus.

Application of RT-PCR designed from the sequence of the local SRSV strain to the screening in viral gastroenteritis outbreaks.

The Yuri strain of small round structured virus (SRSV) was cloned from a fecal specimen in which virus particles were observed by electron microscopy. The most common RT-PCR protocol in Japan, however, using 35/36 and NV81/NV82/SM82 nested primer pairs, could not detect the SRSV genome in this specimen. Nucleotide and amino acid sequence analysis revealed that the Yuri strain is genetically close to the genotype II of SRSV. A novel procedure using primer sets designed from the nucleotide sequence of the Yuri strain was applied to the screening of 119 stool samples obtained from subjects with sporadic diarrhea and 46 samples obtained during seven foodborne gastroenteritis outbreaks. Using this novel procedure, PCR bands were detected in 44% and 52% of the samples, respectively. These detection rates were approximately twice those obtained with the 35/36 and NV81/NV82/SM82 nested primers. In particular, more than 40% of positive samples could be detected by using only the Yuri primer sets. Furthermore, three improvements were made in the RNA preparation, cDNA synthesis, and amplification steps to save materials and time. The background, or extra bands, in the amplification reaction resulting from DNA in the fecal specimens was completely removed by DNase I treatment just before cDNA synthesis. Random nonamers were used as universal primers in the reverse transcription. No difference in sensitivity or specificity was noted in the final results when either random nonamers or specific primers were used. The use of a preamplification step under low stringent conditions before standard amplification under highly stringent conditions compensated for any mismatched bases in the primers with respect to the target sequences. Thus our novel procedure using Yuri primer sets may be useful for the screening of SRSV in the recent SRSV outbreaks in Japan.

Proteoglycans in the nucleus pulposus of canine intervertebral discs after chondroitinase ABC treatment.

Experimental chemonucleolysis of the canine intervertebral disc with chondroitinase ABC and chymopapain was compared during a 52-week period. Roentgenograms and magnetic resonance imaging were used to examine changes in disc space and water content, respectively. Disc space narrowing and reductions in disc water content after chondroitinase ABC treatment were less than that after chymopapain. High-performance liquid chromatography was performed to measure changes in proteoglycans. Similarly to chymopapain, chondroitinase ABC degrades proteoglycans in the nucleus pulposus and decreases their quantity. However, large differences in the molecular weight and acidity of the resynthesized proteoglycans and in the chain length of the resynthesized glycosaminoglycans were observed between the two enzymes. The difference in disc space narrowing and the changes in disc water content between the two enzymes might result from differences in the characteristics of the resynthesized proteoglycans.

Genetic mapping of ossification of the posterior longitudinal ligament of the spine.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is recognized as a common disorder among Japanese and throughout Asia. Estimates of its prevalence are in the range of 1. 9%-4.3%. Although its etiology is thought to involve a multiplicity of factors, epidemiological and family studies strongly implicate genetic susceptibility in the pathogenesis of OPLL. In this study we report an identification of a predisposing locus for OPLL, on chromosome 6p, close to the HLA complex. The evidence for this localization is provided by a genetic-linkage study of 91 affected sib pairs from 53 Japanese families. In this sib-pair study, D6S276, a marker lying close to the HLA complex, gives evidence for strongly significant linkage (P = .000006) to the OPLL locus. A candidate gene in the region, that for collagen 11A2, was analyzed for the presence of molecular variants in affected probands. Of 19 distinct variants identified, 4 showed strong statistical associations with OPLL (highest P = .0004). These observations of linkage and association, taken together, show that a genetic locus for OPLL lies close to the HLA region, on chromosome 6p.