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.

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.

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.

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.

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.

The prognosis and the treatment of patients with a C3/4 spinal cord injury.

Twenty patients with a C3/4 spinal cord injury have been treated in our hospital since 1974. There were 15 new patients. The average follow up period was 68 months, ranging from 7 to 162 months. The 15 new cases were classified as Frankel A in nine cases, B in one, and C in five. Frankel A or B were usually accompanied by either an unstable spinal fracture or by spinal canal stenosis at the C3/4 level. Twelve patients received surgery. At the most recent follow up, eight of the 15 patients (53.3%) had improved according to Frankel's classification. Five, all Frankel A on remission, have died between 2 and 156 months after injury. Seven patients required tracheotomy on account of severe respiratory disturbance.

Cloning and characterization of the cDNA encoding the HA protein of a hemagglutination-defective measles virus strain.

cDNA clones corresponding to the mRNA for the hemagglutinin of the hemagglutination-defective strain AK-1 of measles virus were isolated and characterized. Compared with the prototype Edmonston strain, 60 nucleotide substitutions that resulted in 18 amino acid changes were detected. An additional potential N-linked glycosylation site was added by point mutation, which was supported by the observation that the hemagglutinin of the AK-1 strain was stained more heavily after NaDodSO4-PAGE and periodic acid-Schiff (PAS) staining than the Edmonston strain. Computer-assisted analysis revealed that three reverse turns in the secondary structure had disappeared in the hemagglutinin of the AK-1 strain. Moreover, one of these structural changes occurred in the closely glycosylated region at amino acid residues 168-240, which appeared to be a biologically important functional domain. The isoelectric point calculated from the predicted amino acid sequence became about 1 pH unit more basic in the AK-1 strain than the Edmonston strain. This present study is the first sequence analysis of the hemagglutinin gene in a hemagglutination-defective strain of the measles virus.

Influence of the ultrasonic surgical aspirator on the dura and spinal cord. An electrohistologic study.

The influence of the ultrasonic surgical aspirator on the dura and underlying spinal cord was examined. Spinal-cord-evoked potential was simultaneously recorded. In a test of identical time, the degree of influence on the dura, the pia mater, and the spinal cord increased according to the increase of energy of the ultrasonic surgical aspirator. With 60% energy at 20 seconds and 80% energy at both 10 and 20 seconds, spinal-cord-evoked potential showed wave changes. In light of these results, it is suggested that in using the ultrasonic surgical aspirator on the dura, the electrohistologic safety limit be set at 60% energy and the maximum time duration at one point less than 10 seconds.