Keiro Ono

Repair of rabbit articular surfaces with allograft chondrocytes embedded in collagen gel

In an attempt to repair articular cartilage, allograft articular chondrocytes embedded in collagen gel, were transplanted into full-thickness defects in rabbit articular cartilage. Twenty-four weeks after the transplantation, the defects were filled with hyaline cartilage, specifically synthesising Type II collagen. These chondrocytes were autoradiographically proven to have originated from the transplanted grafts. Assessed histologically the success rate was about 80%, a marked improvement over the results reported in previous studies on chondrocyte transplantation without collagen gel. By contrast, the defects without chondrocyte transplantation healed with fibrocartilage. Immunological enhancement induced by transplanted allogenic chondrocytes or collagen was not significant at eight weeks after treatment, so far as shown by both direct and indirect blastformation reactions. Thus, allogenic transplantation of isolated chondrocytes embedded in collagen gel appears to be one of the most promising methods for the restoration of articular cartilage.

Neck and shoulder pain after laminoplasty. A noticeable complication.

Study Design The authors retrospectively analyzed the prevalence and features of neck and shoulder pain (axial symptoms) after anterior interbody fusion and laminoplasty in patients with cervical spondylotic myelopathy. Objectives To reveal the difference in prevalence of postoperative axial symptoms between anterior interbody fusion and laminoplasty and to clarify the pathogenesis of axial symptoms after laminoplasty. Summary of Background Data Outcome of the cervical surgery is evaluated on neurologic status alone; axial symptoms after laminoplasty rarely have been investigated. Such symptoms, however, are often severe enough to interfere with a persons daily activity. Methods Ninety‐eight patients had surgery for their disability secondary to cervical spondylotic myelopathy. Of those patients, 72 had laminoplasty, and 26 had anterior interbody fusion. The presence or absence of axial symptoms was investigated before and after surgery. The duration, severity, and laterality of symptoms were also recorded. Results The prevalence of postoperative axial symptoms was significantly higher after laminoplasty than after anterior fusion (60% vs. 19%; P < 0.05). In 18 patients (25%) from the laminoplasty group, the chief complaints after surgery were related to axial symptoms for more than 3 months, whereas in the anterior fusion group, no patient reported having such severe pain after surgery. Conclusions The prevalence and severity of axial symptoms after laminoplasty proved to be higher and more serious than has been believed. Such symptoms should be considered in the evaluation of the outcome of cervical spinal surgery.

Natural history of nontraumatic avascular necrosis of the femoral head

We studied the natural history of nontraumatic avascular necrosis of the femoral head (ANFH) in 115 hips in 87 patients, 69 steroid-induced, 21 related to misuse of alcohol and 25 idiopathic. The average length of follow-up was over five years. Collapse occurred most often when the focus of bone necrosis occupied the weight-bearing surface of the femoral head. Flatness of the head due to subchondral fracture was an early manifestation of collapse. Classification into six types based upon the radiographic findings provided an accurate prognosis for individual cases of ANFH which is useful in planning treatment and in assessing its outcome.

Neurologic Complications of Surgery for Cervical Compression Myelopathy

Neurologic complications resulting from surgery for 384 cases of cervical myelopathy (cervical soft disc herniation, spondylosis, ossification of the posterior longitudinal ligament) were reviewed. Surgical procedures performed included 134 anterior interbody fusions (Cloward or Robinson-Smith technique), 70 subtotal corpectomies with strut bone graft, 85 laminectomies, and 95 lamino-plasties. Twenty-one patients (5.5%) sustained neurologic deterioration related to surgery. The deterioration was classified into two types on the basis of the neurologic signs observed: deterioration of spinal cord function or of nerve root function. Manifestations of the former varied from weakness of the hand to tetraparesis. Paralysis of the deltoid and biceps brachii muscles was an exclusive feature of deterioration in the nerve root group. Causes of this paralysis included malalignment of the spine related to graft complications, and a tethering effect on the nerve root following major shifting of the spinal cord after decompression. The causes of deterioration of the cord function included spinal cord injury during surgery, malalignment of the spine associated with graft complication, and epidural hematoma.

Laminoplasty versus subtotal corpectomy. A comparative study of results in multisegmental cervical spondylotic myelopathy.

A comparative study of surgical results was used to determine the tratment of choice for multisegmental cervical spondylotic myelopathy, forty-one patients who received subtotal corpectomy and strut grafting (SCS) and forty-tow undergoing laminoplasty were followed up for at least 2 years after surgery. Regarding factos known to affect surgical prognosis (age at surgery, duration of symptoms, severity of neurologic deficit, anteroposterior canal diameter, transverse area of the cord at the site of maximum compression, number of levels invoived), the two groups were statistically comparable with each other. The sevenity of neurologic deficits was assessed by the Japaneses Orthopaedic Association scale. Results were evaluated in terms of postoperative score and recovery rate, The difference between the recovery rate and final score between the two groups was not statistically significant. Surgical complications were more frequent in the subtotal corpectomy and strut grafting group than in the laminoplasty group. The most frequent complications encountered in the subtotal corpectomy and strut grafting group were related to bone grafting. Spinal aligment worsened in six patients of the laminoplasty group, but none of them suffered from neurologic deterioration, Another disadvantage of subtotal corpectomy and strut grafting was the longer postoperative period of bed rest needed to secure graft stability. We conclude that laminoplasty should be the treatment of choice for multisegmental cervical spondylotic myelopathy when neurologic results, incidence of complications, and postoperstive treatment are taken into consideration.

Ectopic bone induction on and in porous hydroxyapatite combined with collagen and bone morphogenetic protein.

Porous hydroxyapatite (HA-P) discs (5 mm in diameter; 1.5 mm thick; porosity, 80%; mean pore size, 200 micron) were impregnated with purified bovine skin collagen (1 mg/disc) and a small amount of semipurified bone morphogenetic protein (BMP) of sarcoma origin (100 micrograms/disc) and implanted into dorsal muscles of ddY mice. Within one week new ectopic cartilagenous tissue was consistently formed on the surface of the discs adjacent to the host tissue. The cartilage was resorbed and replaced by normal bone containing hematopoietic bone marrow four weeks after implantation and the discs became encased in the newly formed bone. HA-P discs impregnated with only collagen (HA-P/collagen) or only BMP (100 micrograms/disc; HA-P/BMP) did not evoke formation of new cartilage or bone. These results indicate that collagen is effective as a carrier of BMP for expression of the biologic activity of the latter in vivo and that it may be of practical use as a carrier of BMP with synthetic biomaterials.

A noxious stimulus induces the preprotachykinin-A gene expression in the rat dorsal root ganglion: a quantitative study using in situ hybridization histochemistry

Using in situ hybridization histochemistry, we examined the biosynthesis of the preprotachykinin-A (PPTA) mRNAs, which code for substance P (SP) and also a related peptide, substance K (SK), in the rat dorsal root ganglion (DRG). The animals were injected with a small amount of formalin in the right hindpaw for nociceptive chemical stimulation. Analysis of hybridization signals in the emulsion autoradiography showed that the lumbar-5 DRG neurons expressing PPTA mRNAs were significantly increased in number and signal intensity on the formalin-injected side. Such elevation of the PPTA mRNA expression in the DRG was observed as early as 3 h after formalin injection. These results show that the expression of the PPTA gene is activated by chemogenic noxious stimuli.

Choice of surgical treatment for multisegmental cervical spondylotic myelopathy.

Three surgical procedures for multisegmental cervical spondylotic myelopathy were evaluated on the basis of a follow-up study (12-157 months) of 95 patients. Twenty-four patients were treated by extensive laminectomy, 50 by anterior interbody fusion by the Cloward and/ or Smith-Robinson techniques, and 21 by subtotal spondylectomy and fusion. Results of subtotal spondylectomy were significantly (P < 0.01) better when compared with those of the other two procedures. It was concluded that spondylosis up to three disc levels should be treated by subtotal spondylectomy and fusion regardless of the canal diameter. When involvement extended four or more levels, extensive laminectomy was recommended.

Canal diameter, anteroposterior compression ratio, and spondylotic myelopathy of the cervical spine.

Nine patients with cervical spondylotic myelopathy, diagnosed during life, were subjected to detailed clinicopathologic study. The degree of cord destruction was in good correlation with the ratio of the anteroposterior diameter to the transverse diameter, designated as an anteroposterior compression ratio. Within the factors responsible for decrease in the ratio, developmental narrowing of the spinal canal was the most significant, and multiplicity of spondylotic protrusion less so. The former resulted in an extensive demyelination of the posterolateral funiculus and infarction of the gray matter. Recurrent trauma proved to cause distinct manifestations and cord pathology. Clinicopathologic correlations were also examined from the neurologic findings at the terminal stage.

Prognostic significance of Ki‐67 reactivity in soft tissue sarcomas

Proliferative activity of soft tissue sarcomas (STS) in 34 cases was estimated by immunohistochemical procedures (avidin‐biotin complex [ABC] method) with monoclonal antibody Ki‐67 which reacts with a nuclear antigen expressed in all phases of cell cycle except G0. In 20 of 34 cases (59%), varying numbers of Ki‐67‐positive tumor cells were detected with a range from 5 to 382 per 10 high power fields (HPF) (mean 57.2/10 HPF). Ki‐67 index (the number of Ki‐67‐positive tumor cells/10 HPF) positively correlated with mitotic count (r = 0.428, P < 0.02), cellularity (r = 0.447, P < 0.01), and histologic grade (r = 0.473, P < 0.01). The Ki‐67 low index group (less than 50/10 HPF) showed more favorable prognosis than the high index group (more than 50/10 HPF) (P < 0.005). Three cases with low mitotic count and unfavorable prognosis were proved to be the Ki‐67 high index group (142‐382/10 HPF). These results indicated that reactivity of tumor cells for Ki‐67 is a useful prognostic marker in the patients with STS, and might be used as one of the histologic factors for the grading of STS.