Jun Mizutani

Application of full-scale three-dimensional models in patients with rheumatoid cervical spine.

Full-scale three-dimensional (3D) models offer a useful tool in preoperative planning, allowing full-scale stereoscopic recognition from any direction and distance with tactile feedback. Although skills and implants have progressed with various innovations, rheumatoid cervical spine surgery remains challenging. No previous studies have documented the usefulness of full-scale 3D models in this complicated situation. The present study assessed the utility of full-scale 3D models in rheumatoid cervical spine surgery. Polyurethane or plaster 3D models of 15 full-sized occipitocervical or upper cervical spines were fabricated using rapid prototyping (stereolithography) techniques from 1-mm slices of individual CT data. A comfortable alignment for patients was reproduced from CT data obtained with the patient in a comfortable occipitocervical position. Usefulness of these models was analyzed. Using models as a template, appropriate shape of the plate-rod construct could be created in advance. No troublesome Halo-vests were needed for preoperative adjustment of occipitocervical angle. No patients complained of dysphasia following surgery. Screw entry points and trajectories were simultaneously determined with full-scale dimensions and perspective, proving particularly valuable in cases involving high-riding vertebral artery. Full-scale stereoscopic recognition has never been achieved with any existing imaging modalities. Full-scale 3D models thus appear useful and applicable to all complicated spinal surgeries. The combination of computer-assisted navigation systems and full-scale 3D models appears likely to provide much better surgical results.

Safe atlantoaxial fixation using a laminar screw (intralaminar screw) in a patient with unilateral occlusion of vertebral artery: case report.

Study Design. A case of atlantoaxial fusion using an intralaminar (unilateral-crossing laminar screw) screw is presented in a patient with unilateral vertebral artery communication with the basilar artery. Objectives. To document the significance of the intralaminar screw technique in the aforementioned case. Summary of Background Data. Vertebral artery injury is directly linked with intraoperative or perioperative death if the vertebral artery communicates only unilaterally to the basilar artery or has an obvious dominant side. In this situation, irrespective of whether the pedicle is confirmed to be sufficient for pedicle screw placement, if the vertebral artery is violated, fatal complications will occur. The literature reports that even proficient surgeons cannot guarantee 100% accuracy in pedicle screw placement. The intralaminar screw technique is currently the safest with regard to avoiding violation of the vertebral artery. Biomechanical studies have also shown this technique to ensure sufficient strength. Methods. The patient had rheumatoid atlantoaxial subluxation, and the right vertebral artery alone communicated with basilar artery, while the left ended blind. She underwent atlantoaxial fixation with an intralaminar screw (unilateral-crossing laminar screw) of the axis and lateral mass atlas screws inserted via the posterior arch. Results. The intralaminar screw (unilateral-crossing laminar screw) was completed, and comprised lateral mass atlas screws and rods. There were no complications during and after surgery. Good bone union was achieved. Conclusion. Patients with unilateral dominant vertebral artery are good candidates for the intralaminar screw technique, even if the pedicle anatomy is sufficient to insert pedicle screws.

(-)-Epigallocatechin Gallate Reduces Platelet-Derived Growth Factor-BB-Stimulated Interleukin-6 Synthesis in Osteoblasts: Suppression of SAPK/JNK

We previously showed that the mitogen-activated protein (MAP) kinase superfamily, p44/p42 MAP kinase, p38 MAP kinase, and stress-activated protein kinase (SAPK)/c-Jun N-terminal (JNK), positively plays a part in the platelet-derived growth factor-BB- (PDGF-BB-) stimulated synthesis of interleukin-6 (IL-6), a potent bone resorptive agent, in osteoblast-like MC3T3-E1 cells while Akt and p70 S6 kinase negatively regulates the synthesis. In the present study, we investigated whether (-)-epigallocatechin gallate (EGCG), one of the major green tea flavonoids, affects the synthesis of IL-6 in these cells and the mechanism. EGCG significantly reduced the IL-6 synthesis and IL-6 mRNA expression stimulated by PDGF-BB, EGCG reduced the PDGF-BB-stimulated IL-6 synthesis also in primary-cultured osteoblasts. EGCG had no effect on the levels of osteocalcin and osteoprotegerin in MC3T3-E1 cells. The PDGF-BB-induced autophosphorylation of PDGF receptor β was not suppressed by EGCG. The PDGF-BB-induced phosphorylation of p44/p42 MAP kinase and p38 MAP kinase was not affected by EGCG. On the other hand, EGCG markedly suppressed the PDGF-BB-induced phosphorylation of SAPK/JNK. Finally, the PDGF-BB-induced phosphorylation of Akt and p70 S6 kinase was not affected by EGCG. These results strongly suggest that EGCG inhibits the PDGF-BB-stimulated synthesis of IL-6 via suppression of SAPK/JNK pathway in osteoblasts.

MRI Findings in Residual Hip Dysplasia

Background Residual subluxation of the hip is a major problem in pediatric orthopaedics. Corrective surgery by Salter innominate osteotomy is performed for residual subluxation before school age. Common indications for corrective surgery are determined based on the clinical condition, x-ray images, and arthrographic images. However, the surgical indications vary among institutions. Thus, further information that can predict acetabular growth with certainty is needed for precise decision- making. This study focused on signal intensity changes on magnetic resonance (MR) images within the weight-bearing portion of the acetabulum to determine whether these signal intensity changes could predict acetabular growth. Methods Thirty-six patients who showed residual subluxation after reduction of developmental dysplasia of the hip and whose MRIs were taken when they were around 3 years old were studied. Corrective surgery was performed in 14 patients, whereas the remaining 22 patients were followed conservatively. The presence of a high-signal intensity area (HSIA) within the weight-bearing portion of the acetabular cartilage on T2-weighted MR coronal section images was investigated, and the correlation between HSIA presence and acetabular growth was examined. Results All patients who underwent corrective surgery showed an HSIA within the weight-bearing portion of the acetabular cartilage on T2-weighted MR images before surgery. After surgery, all patients showed HSIA disappearance or decrease. In patients who were followed conservatively, HSIA-positive patients had poor acetabular growth, whereas HSIA-negative patients had favorable acetabular growth. Conclusions HSIAs in the acetabular cartilage may be caused by an extraordinary stress load from the femoral head. The presence of HSIA on MRI may prevent acetabular growth. HSIA on MRI appears to be a significant decision-making tool for corrective surgery. Level of Evidence III.

Ultrastructural changes at the myotendinous junction induced by exercise

BackgroundAlthough exercise is believed to reduce the risk of rupture of the myotendinous junction, exercise-induced structural changes in this region have not been studied. We examined exercise-induced ultrastructural changes in the myotendinous junction of the lower legs in rats.MethodsTen adult male LETO rats were used. Five rats were randomly placed in the Exercise group; the remaining five were used as controls and placed in the non-Exercise group. Running exercise was performed every day for 4 weeks. The tibialis anterior and gastrocnemius muscles were then removed from both legs from each animal in the two groups. The specimens were subsequently examined by transmission electron microscopy (TEM). Numerous finger-like processes were observed at the myotendinous junction. The changes in frequency of branching of the finger-like process (the number of times one finger-like process branched) and the direction of the processes (the angle of the major axis of a finger-like process to the longitudinal direction of the muscle fiber) were studied. To evaluate the two indicators above, each 10 fingerlike process was randomly and separately selected from the tibialis anterior and gastrocnemius muscles of rats, providing 50 finger-like processes of both muscles for evaluation per group.ResultsIn terms of the frequency of branching of the fingerlike processes, the mean values obtained in the non-Exercise group were 0.04 and 0.18 times, respectively, in the tibialis anterior and gastrocnemius muscles and were 0.38 and 1.16 times, respectively, in these two muscles in the Exercise group. Regarding the direction of the finger-like processes, the values were 4.1° and 3.6°, respectively in the non-Exercise group and 10.4° and 14.5°, respectively in the Exercise group. The differences between the two animal groups were significant.ConclusionsMorphological changes in the myotendinous junction occurred as an adaptation to tension increased by exercise.

Anatomical basis of the medial sural artery perforator flap in Asians

Forty-four lower limbs preserved in formaldehyde from cadavers of adult Asians were used. In all specimens 1–5 perforating branches from the medial sural artery were found. No perforators were found higher than 5 cm or lower than 17.5 cm from the popliteal crease. In the most common place (16/44, 36%) in which 2 perforators were found, the proximal one was a mean of 9.6 cm away from the popliteal crease, and the distant one 12.8 cm. All perforators were in an area between 0.5 cm and 4.5 cm from the midline of the gastrocnemius muscles. Because of the differences in the length of the muscle belly, the distribution of perforators may differ between white people and Asians. It should be safe to raise this flap in Asians, because the anatomical comparison of the perforators of the medial sural artery between Asians and white people is now clear.

Patch technique for repair of a dural tear in microendoscopic spinal surgery

A dural tear is a common but troublesome complication of endoscopic spinal surgery. The limitations of space make repair difficult, and it is often necessary to proceed to an open operation to suture the dura in order to prevent leakage of cerebrospinal fluid. We describe a new patch technique in which a small piece of polyglactin 910 is fixed to the injured dura with fibrin glue. Three pieces are generally required to obtain a watertight closure after lavage with saline. We have applied this technique in seven cases. All recovered well with no adverse effects. MRI showed no sign of leakage of cerebrospinal fluid.

Regulation by heat shock protein 27 of osteocalcin synthesis in osteoblasts.

We have previously reported that various stimuli, including sphingosine 1-phosphate, are able to induce heat shock protein (HSP) 27 in osteoblast-like MC3T3-E1 cells. However, the precise role of HSP27 in bone metabolism has not been satisfactory clarified. In this study, we investigated the effect of HSP27 on osteocalcin synthesis induced by bone morphogenetic protein (BMP)-4 or T₃ in these cells. In MC3T3-E1 cells, pretreatment with sphingosine 1-phosphate, sodium arsenite, or heat stress caused the attenuation of osteocalcin synthesis induced by BMP-4 or T₃ with concurrent HSP27 induction. To further investigate the effect of HSP27, we established stable HSP27-transfected cells. The osteocalcin synthesis was significantly reduced in the stable HSP27-transfected MC3T3-E1 cells and normal human osteoblasts compared with empty-vector transfected cells. On the other hand, anisomycin, a p38 MAPK activator, caused the phosphorylation of HSP27 in both sphingosine 1-phosphate-stimulated untransfected MC3T3-E1 cells and HSP27-transfected MC3T3-E1 cells. An immunofluorescence microscopy study showed that the phosphorylated HSP27 induced by anisomycin concentrated perinuclearly in these cells, in which it colocalized with the endoplasmic reticulum. We also established stable mutant-HSP27-transfected cells. Osteocalcin synthesis induced by either BMP-4 or T₃ was markedly suppressed in the nonphosphorylatable HSP27-overexpressing MC3T3-E1 cells compared with the phosphomimic HSP27-overexpressing cells. In contrast, the matrix mineralization was more obvious in nonphosphorylatable HSP27-overexpressing cells than that in phosphomimic HSP27-overexpressing cells. Taken together, these results strongly suggest that unphosphorylated HSP27 has an inhibitory effect on osteocalcin synthesis, but has a stimulatory effect on mineralization, in osteoblasts.

New needle biopsy technique for lumbar pyogenic spondylodiscitis.

Study Design. Case series. Objective. To improve the isolation rate for pyogenic spondylodiscitis, we developed a new needle biopsy technique. Summary of Background Data. The biggest problem in treating lumbar pyogenic spondylodiscitis is a low success rate in isolating a causative microorganism. The rates have been reported 42% to 64%. Methods. There are 3 steps: (A) Insert a 21-G needle as for discography, aspirate pus or fluid as specimen. (B) If step A fails, inject saline and collect fluid as reflux

Rho-kinase inhibitors decrease TGF-β-stimulated VEGF synthesis through stress-activated protein kinase/c-Jun N-terminal kinase in osteoblasts

We have previously reported that transforming growth factor-beta (TGF-beta) stimulates the synthesis of vascular endothelial growth factor (VEGF) through p44/p42 mitogen-activated protein (MAP) kinase, p38 MAP kinase and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) in osteoblast-like MC3T3-E1 cells. In order to investigate whether Rho-kinase is involved in the TGF-beta-stimulated VEGF synthesis in these cells we examined the effects of Rho-kinase inhibitors on the VEGF synthesis. TGF-beta time-dependently induced the phosphorylation of myosin phosphatase targeting subunit (MYPT-1) which is a well known substrate of Rho-kinase. Y27632 and fasudil, Rho-kinase inhibitors, significantly reduced the TGF-beta-stimulated VEGF synthesis as well as the MYPT-1 phosphorylation. Y27632 and fasudil failed to affect the TGF-beta-induced phosphorylation of p44/p42 MAP kinase, p38 MAP kinase or Smad2. On the contrary, Y27632 as well as fasudil markedly suppressed the TGF-beta-induced phosphorylation of SAPK/JNK. Taken together, our results strongly suggest that Rho-kinase regulates TGF-beta-stimulated VEGF synthesis via SAPK/JNK activation in osteoblasts.