Correlations and time-dependent changes of upper arm performance tests, the Japanese Orthopaedic Association score, and a newly developed patient-based outcome measure : the Japanese Orthopaedic Cervical Myelopathy Questionnaire

AIMS

In this prospective observational study, we investigated the time-dependent changes and correlations of upper arm performance tests (ten-second test and Simple Test for Evaluating Hand Function (STEF), the Japanese Orthopaedic Association (JOA) score, and the JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) in 31 patients with cervical myelopathy who had undergone surgery.

PATIENTS AND METHODS

We hypothesised that all the indices correlate with each other, but show slightly different recovery patterns, and that the newly described JOACMEQ is a sensitive outcome measure.

RESULTS

Peak recoveries were achieved one month post-operatively in the ten-second test and JOACMEQ upper extremity function (UEF) subscale, and at three months in the JOA and STEF scores. The recoveries of all indices were maintained until six months post-operatively. The upper extremity function (UEF) subscale in the JOACMEQ showed the strongest correlation with STEF although all the indices correlated with each other. Patients with ≥ 20 and < 20 acquired points in the UEF subscale were classified into the UEF-improved and UEF-unimproved groups. Comparisons between the groups showed that pre-operative evaluation of "coordinated motion" of the STEF was significantly low in the UEF-unimproved group.

CONCLUSION

These results indicate that the JOACMEQ is a concise, sensitive, patient-based outcome measure for evaluating functional recovery in patients with cervical myelopathy who have undergone surgery. Cite this article: Bone Joint J 2016;98-B:990-6.

Surgical treatment for skeletal metastases from soft tissue sarcomas: experience with 23 lesions in 20 patients

Purpose. This paper reports the procedures and the clinical results of a series of surgical treatments for skeletal metastases from soft tissue sarcomas.Subjects and methods. Surgical treatment of metastatic bony lesions from soft tissue sarcomas has been carried out over a 20 year period (1975-1996). Thirty-two patients developed skeletal metastases from soft tissue sarcomas, and 20 of these cases received surgical treatment. The 23 metastatic bony lesions in these 20 patients were treated using the following surgical approaches: wide resection with prosthetic replacement in five lesions, wide or marginal resection without reconstruction in four lesions, intramedullarly nailing with curettage and methylmethacrylate cementation in four lesions, marginal resection of vertebral body with replacement by a ceramic prosthesis in three lesions, laminectomy in three lesions, intramedullarly nailing in two lesions, and curettage in two lesions.Results. Relief of pain was achieved in 17 of the 20 patients. The ambulatory status of the patients with metastasis in the lower extremity or periacetabular region was significantly improved in nine of 10 cases. Seventeen patients died of disease, with a mean survival period of 17.9 months after surgery for metastasis.Discussion. Although surgical treatment for skeletal metastases from soft tissue sarcomas cannot save the life of the patient, it can be of value in improving their well-being and overall quality of life. In these cases, surgical intervention may be more frequently indicated than in tumors with an osteoblastic or mixed pattern.

Control of fracture reduction robot using force/torque measurement

We have developed a surgical robotic system for femoral fracture reduction employing indirect traction. Indirect traction in fracture reduction is a generally used surgical method for preventing complications such as bone splits caused by high stress on bones. For traction, a patient's foot is gripped by a jig and pulled to the distal side. Indirect traction has the advantage of distributing bone stress by utilizing a strong traction force; however, this procedure does not accurately control the proper positioning of fractured fragments when a surgical robot is used. The human leg has knee and an ankle joints, and thus robotic motion presents problems in not being able to directly propagate reduction motion to a fractured femoral fragment, rendering control of bone position difficult. We propose a control method for fracture reduction robots using external force/torque measurements of the human leg to achieve precise fracture reduction. Results showed that the proposed method reduced repositioning error from 6.8 mm and 15.9 degrees to 0.7 mm and 5.3 degrees, respectively.

Accuracy evaluation of surface-based registration methods in a computer navigation system for hip surgery performed through a posterolateral approach

OBJECTIVE

Many computer navigation systems have recently been developed for brain surgery, and the use of such systems in orthopedic surgery is increasing. Intraoperative registration of preoperative images is one of the most important steps in controlling the overall accuracy of computer navigation systems. Various parameters, such as CT-scan slice thickness, reconstruction pitch, intraoperative data sampling area, and data sampling volume, may affect the accuracy of registration. The purpose of this study was to evaluate the effect of the aforementioned parameters on the accuracy of registration for hip surgery performed through a posterolateral approach, and to find a clinically suitable trade-off between accuracy and surgical invasiveness.

MATERIALS AND METHODS

One cadaveric pelvis and one cadaveric femur were used for this study. Four alumina ceramic balls with a diameter of 28 mm and within 1 micrometer of sphericity were attached to the pelvis, and three similar balls attached to the femur, to determine relative position. CT-scan images of the pelvis and femur were obtained with a helical scanner. Three sets of slice thickness and slice pitch were chosen for data acquisition, and two additional sets of reconstructed data were made. Bone contours were extracted by cutting out the surrounding substrate at a given CT number threshold, and surface models of the bone were made from the resultant data. The positions of the pelvis and femur were tracked by LED markers attached to the bone using an optical three-dimensional position sensor (OPTOTRAK). Registration of the computer models to the real objects was performed by measuring the position of a certain number of surface points on each object with an OPTOTRAK pen-probe.

RESULTS AND CONCLUSION

Slice thickness and reconstruction pitch affected the accuracy of registration. As the sampling area was expanded from the periarticular area to the distant peripheral area, accuracy increased slightly. Accuracy did not increase when the whole area was used, but in fact decreased, especially in the femur. The positive effect of increasing the number of sampling points was saturated at 30 points when the surface of the periarticular area was sampled. The following trade-off between accuracy and invasiveness, in terms of various parameters of preoperative and intraoperative data, is proposed as clinically optimal: perform the CT scan with 3-mm slice thickness and 1-mm reconstruction pitch, and sample the periarticular area with 30 sampling points. With these parameters, the accuracy of registration was 1.2 mm and 0.9 degrees of bias with 0.7 mm and 0.3 degrees of RMS in the pelvis, and 1.4 mm and 0.6 degrees of bias with 1.3 mm and 0.3 degrees of RMS in the femur.

Localization of cathepsins D, K, and L in degenerated human intervertebral discs

STUDY DESIGN

Localization of cathepsins D, K, and L in degenerated intervertebral discs was examined by immunohistochemistry.

OBJECTIVES

To determine the involvement of cathepsins in the pathomechanism of intervertebral disc degeneration by monitoring the immunolocalization of cathepsins in degenerated intervertebral disc tissue.

SUMMARY OF BACKGROUND DATA

Cathepsins D, K, and L are enzymes that contribute to the matrix destruction seen in the articular cartilage affected by osteoarthritis and rheumatoid arthritis. However, little is known about the contribution of these cathepsins to intervertebral disc degeneration.

METHODS

Paraffin-embedded sections of degenerated intervertebral disc tissue collected at the time of surgery (13 discs from 12 patients) were immunohistochemically stained with antibodies for cathepsins D, K, and L. For further characterization of the stained cells, immunohistochemical detection of CD68 and TRAP staining were performed.

RESULTS

Hematoxylin and eosin staining revealed obvious signs of degeneration in all sections. Cathepsins D and L were immunolocalized in disc fibrochondrocytes at various sites exhibiting degeneration. Cathepsins K were found in tartrate-resistant acid phosphatase-positive multinucleated cells, in particular near the cleft within the cartilaginous endplate. However, few cells were positive for these cathepsins in anulus fibrosus that maintained the lamellar structure of collagen fibers.

CONCLUSIONS

Marked expression of cathepsins D and L was observed at the site of degeneration. Cathepsins D and K localized in tartrate-resistant acid phosphatase-positive multinucleated cells existed at the cleft between the cartilaginous endplate and vertebral body. The site-specific localization of these cathepsins suggests the association of these proteinases with endplate separation and disorganization of the anulus fibrosus in degenerative spinal disorders.

Localization of cathepsins G and L in spontaneous resorption of intervertebral discs in a rat experimental model

To determine the involvement of cathepsins G and L in the mechanism of spontaneous resorption of herniated intervertebral discs, localization of these cathepsins in this process was examined immunohistochemically using a rat model of autologous transplantation of coccygeal discs. Rat coccygeal discs were resected and autotransplanted into the subcutaneous space of the skin of the back. Paraffin-embedded sections of intervertebral disc tissue, harvested at various post-transplantational periods, were immunohistochemically stained with antibodies for cathepsin G, cathepsin L, MMP-1, MMP-3 and ED-2. The number of positive cells was counted in each part of the transplanted discs. Immunolocalization of cathepsins G and L in various types of disc cells was first observed early in the post-transplantation period. From two days after the operation, histology showed invasion by granulation tissue, with many macrophages, in all sections. Subsequently, the number of macrophages in granulation tissue was observed to increase, along with a gradual increase in the percentage of cells positive for MMP-1 and MMP-3. In addition to the ability of cathepsins G and L to degrade major extracellular matrix components of intervertebral discs, cathepsin G is capable of activating latent pro-MMPs. The up-regulation of cathepsins G and L in the intervertebral disc tissue in this spontaneous resorption model suggests that these proteinases may be involved in degradation of extracellular matrix, leading to the natural resorption of herniated discs.

The relationship between apoptosis of endplate chondrocytes and aging and degeneration of the intervertebral disc

STUDY DESIGN

Apoptosis in cervical intervertebral disc cells and cartilaginous endplate cells was examined by the nick end labeling (TUNEL) technique during the process of natural aging and in a mouse experimental spondylosis model.

OBJECTIVES

To determine the role of apoptosis in aging and degeneration of intervertebral discs by monitoring chronologic changes in the quantity and localization of apoptotic cells.

SUMMARY OF BACKGROUND DATA

Apoptosis occurs within human intervertebral discs, but little is known about the pathologic significance of this process. On the other hand, the cartilaginous endplate is known to decrease in thickness and to disappear with aging and degeneration. The cause of this age-related change remains unclear.

METHODS

A mouse spondylosis model was prepared via surgical resection of the posterior spinal element in 12 mice to examine the experimentally induced spondylosis process. Eighteen naturally aged mice were also used to examine the influence of aging. Paraffin-embedded midsagittal sections of the cervical spine were obtained 2, 3, 6, and 12 months after surgery in the spondylosis model and in the age-matched naturally aged mice, as well as in 4-week-old and 18-month-old naturally aged mice. Sections were stained with hematoxylin and eosin, safranin-O, and the TUNEL procedure. The number of apoptotic cells and vital cells were counted in the cartilaginous endplate of the intervertebral disc excluding the growth cartilage, and the degree of disappearance of the cartilaginous endplate was evaluated.

RESULTS

Apoptosis, particularly noticeable in the cartilaginous endplate, increased with age and resulted in a marked decrease in cell density. Subsequently, the structure of the cartilaginous endplate began to disappear. Apoptosis was more evident and the structure of the cartilaginous endplate began to disappear more rapidly in the surgically treated group than in the naturally aged group.

CONCLUSIONS

TUNEL-positive cells in the cartilaginous endplate increased with age, with destruction of the cartilaginous endplate after apoptosis (TUNEL-positive cell death). The application of the spondylosis model increased the incidence of apoptosis preceding the development of spondylosis. This suggests that apoptosis plays a role in the age-related changes seen in the cartilaginous endplate of the intervertebral disc and in the experimentally induced spondylosis process.

Mechanisms of age-related decline in insulin-like growth factor-I dependent proteoglycan synthesis in rat intervertebral disc cells

STUDY DESIGN

Age-related fluctuations in insulin-like growth factor-I dependent proteoglycan synthesis in rat intervertebral disc cells were investigated.

OBJECTIVES

The purpose of this study was to determine whether synthetic responses to insulin-like growth factor-I decline with age and to explore the possibility that an age-related increase in the expression of insulin-like growth factor binding proteins suppresses matrix synthesis in intervertebral disc cells.

SUMMARY AND BACKGROUND DATA

Several studies have reported that the responsiveness of chondrocytes to insulin-like growth factor-I decreases with age and furthermore that this phenomenon may be related to increased expression of insulin-like growth factor binding proteins by chondrocytes.

MATERIALS AND METHODS

Nucleus pulposus tissue and cells were obtained from the coccygeal vertebrae of 8-week-old, 40-week-old, and 120-week-old rats. Age-related changes in the expression of insulin-like growth factor-I and its receptor were assessed together with insulin-like growth factor-I dependent proteoglycan synthesis by the cultured nucleus pulposus cells. Also, western blot analysis of insulin-like growth factor binding protein-1 was carried out, and further examination was performed of insulin-like growth factor-I signal transduction through tyrosine phosphorylation of insulin receptor substrate-1, which is a signal transducer of insulin-like growth factor-I.

RESULTS

Semiquantitative reverse transcription polymerase chain reaction analysis indicated that the expression of insulin-like growth factor-I receptor in 120-week cells decreased clearly in comparison with the cells of younger animals. By contrast, insulin-like growth factor-I dependent proteoglycan synthesis decreased with age, and the sharpest decline of synthesis was found between 8-week and 40-week cells, although the level of insulin-like growth factor-I/insulin-like growth factor-I receptor gene expression was maintained in 40-week-old animals. Consistent with the results of proteoglycan synthesis, the expression of phosphorylated insulin receptor substrate-1 decreased with age. Thus, the expression of insulin-like growth factor binding protein-1 and proteoglycan synthesis was investigated by use of Long R3 insulin-like growth factor-I, which was not influenced by insulin-like growth factor binding proteins. Insulin-like growth factor binding protein-1 was strongly expressed in 40-week cells in comparison with the expression in 8-week cells. Furthermore, proteoglycan synthesis in 40-week cells supplemented with Long R3 insulin-like growth factor-I was upregulated in comparison with that in 40-week cells supplemented with insulin-like growth factor-I.

CONCLUSION

The present findings indicate that the age-related decline in insulin-like growth factor-I dependent proteoglycan synthesis in nucleus pulposus is caused, at least in part, by the increase in insulin-like growth factor binding proteins at the early stages of aging, and further suggest that a loss of proteoglycan synthesis during the late stages of aging is caused by the downregulation of insulin-like growth factor-I receptor in addition to an increase in insulin-like growth factor binding proteins.

Interobserver and intraobserver reliability of the japanese orthopaedic association scoring system for evaluation of cervical compression myelopathy

STUDY DESIGN

The inter- and intraobserver reliabilities of an assessment scale for cervical compression myelopathy were examined statistically. This scoring system consists of seven categories: motor function of fingers, shoulder and elbow, and lower extremity; sensory function of upper extremity, trunk and lower extremity; and function of the bladder. It evaluates the severity of myelopathy by allocating points based on degree of dysfunction in each category.

OBJECTIVES

To determine the inter- and intraobserver reliabilities of the revised scoring system (17 - 2 points) for cervical compression myelopathy proposed by the Japanese Orthopedic Association.

SUMMARY OF BACKGROUND DATA

Several scales to assess clinical outcome from treatment of cervical compression myelopathy have been proposed. Most of these scales include items evaluated by observers. However, no system, including the Japanese Orthopedic Association scoring system, has yet been validated in terms of interobserver reliability.

METHODS

From five different university hospitals, 10 spine surgery specialists, 10 orthopedic surgeons who had just passed the board examination of the Japanese Orthopedic Association, and 13 residents in the first or second year of orthopedic residency programs were chosen. The participants in this study were 29 patients with myelopathy secondary to ossification of the posterior longitudinal ligament selected from five participating university hospitals. Several surgeons interviewed each patient twice at intervals of 1 to 6 weeks. Inter- and intraobserver reliabilities of the total score for all categories were evaluated by the intraclass correlation coefficient. The extension of the kappa coefficient of Kraemer also was calculated for each category to assess reliability of multivariate categorical data.

RESULTS

The interobserver reliability of the total score for the first interview (intraclass correlation coefficient = 0.813) and the intra- and interobserver reliabilities of the total score (intraclass correlation coefficient = 0.826) were high. The level of experience and the hospital slightly affected the reliability of the Japanese Orthopedic Association scoring system. The kappa values for intraobserver data generally were high in each category, whereas the kappa values for interobserver data were relatively low for the categories of shoulder-elbow motor function and lower extremity sensory function.

CONCLUSIONS

The inter- and intraobserver reliabilities of the Japanese Orthopedic Association scoring system for cervical myelopathy were high, suggesting that this system is useful for assessment of cervical myelopathy in comparative studies of treatment.

Activation and localization of cartilage-derived morphogenetic protein-1 at the site of ossification of the ligamentum flavum

Localization and expression of cartilage-derived morphogenetic protein (CDMP)-1 in tissues at the site of ossification of the ligamentum flavum (OLF) were examined by immunohistochemistry and in situ hybridization. The CDMP-1 protein and messenger ribonucleic acid (mRNA) were localized in spindle-shaped cells and chondrocytes in the OLF tissues. CDMP-1 was not detected in cells in non-ossified sites. These data indicate that CDMP-1 is locally activated and localized in spindle-shaped cells and chondrocytes at the site of OLE. Given the previously reported promoting action of CDMP-1 for chondrogenesis, the current results suggest that CDMP-1 may be involved in the progression of OLF, leading to the narrowing of spinal canal and thus causing severe clinical manifestations.

Ossification of the ligamentum flavum associated with osteoblastoma: a report of three cases

We report three cases of spinal osteoblastoma with ossification of the ligamentum flavum (OLF) adjacent to the tumor. The patients in this report, all young adults, had no symptoms except for back pain. Computed tomography (CT) demonstrated a typical radiolucent nidus in the spinal pedicle/lamina with a dense sclerotic rim. In addition, ectopic bone formation at the insertion point of the ligamentum flavum adjacent to the tumor was clearly illustrated. Magnetic resonance imaging (MRI) revealed the tumor and surrounding inflammatory responses, but OLF was not detected clearly. Histological examination revealed endochondral ossification of the ligamentum flavum that is quite unusual for normal young adults. Immunohistochemical assays in one case demonstrated that bone morphogenetic protein (BMP)-2/4 was expressed in the osteoblastic tumor cells. This case raises the possibility that BMPs secreted from the tumor cells triggered ectopic ossification in the spinal ligament.

Subtotal corpectomy versus laminoplasty for multilevel cervical spondylotic myelopathy: a long-term follow-up study over 10 years

STUDY DESIGN

A retrospective study was conducted.

OBJECTIVE

To compare the long-term outcomes of subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

No study has compared the long-term outcomes between subtotal corpectomy and laminoplasty for multilevel cervical spondylotic myelopathy.

METHODS

In this study, 23 patients treated with subtotal corpectomy and 24 patients treated with laminoplasty were followed up for 10 to 14 years after surgery. Neurologic recovery, late deterioration, axial pain, radiographic results (degenerative changes at adjacent levels, alignment, and range of motion of the cervical spine), and surgical complications were compared between the two groups.

RESULTS

No significant difference in neurologic recovery was found between the two groups 1 and 5 years after surgery, or at the latest follow-up assessment. Neurologic status deteriorated in one patient of the subtotal corpectomy group because of adjacent degeneration, and in one patient of the laminoplasty group because of hyperextension injury. Axial pain was observed in 15% of the corpectomy group and in 40% of the laminoplasty group (P < 0.05). In the corpectomy group, listhesis exceeding 2 mm developed at 38% of the upper adjacent levels, and osteophyte formation at 54% of the lower adjacent levels. In the laminoplasty group, kyphotic deformity developed in one patient (6%) after surgery. In the corpectomy group, the mean vertebral range of motion had decreased from 39.4 degrees to 19.2 degrees (49%) by the final follow-up assessment. In the laminoplasty group, the mean vertebral range of motion had decreased from 40.2 degrees to 11.6 degrees (29%) by the final follow-up assessment. Neurologic complications related to the surgery occurred in two patients (one myelopathy from bone graft dislodgement and one C5 root palsy from bone graft fracture) of the corpectomy group and four patients (C5 root palsy) of the laminoplasty group. All of these patients recovered over time. The corpectomy group needed longer operative time (P < 0.001) and tended to have more blood loss (P = 0.24). Six patients in the corpectomy group needed posterior interspinous wiring because of pseudarthrosis.

CONCLUSIONS

Subtotal corpectomy and laminoplasty showed an identical effect from a surgical treatment for multilevel cervical spondylotic myelopathy. These neurologic recoveries usually last more than 10 years. In the subtotal corpectomy group, the disadvantages were longer surgical time, more blood loss, and pseudarthrosis. In the laminoplasty group, axial pain occurred frequently, and the range of motion was reduced severely.

Radiographic analysis of lumbar spine for low-back pain in the general population

We sought to demonstrate a correlation between low-back pain (LBP) and the plain radiographic findings of the lumbar spine in the general population based on an analysis of 838 persons, 387 of whom presented with complaints of low-back pain. The incidence of intervertebral narrowing and irregular ossification of the vertebral end-plate image increased consistently with age and was higher in the presence of LBP in any age or gender group. Multiregression analysis was performed with the imaging factors as multivariates. As a result, multiregression equations with irregular ossification of the vertebral end-plate image, intervertebral narrowing, spondylolisthesis and abnormal lumbar lordotic angle combined as variates showed the highest significance as predictors of a relationship with LBP. The discrimination analysis was performed using the linear discriminant function, resulting in a true discrimination rate of 65%. Plain radiography of the lumbar spine is thus significant as it provides information which can be evaluated as meaningful findings in the investigation of LBP. In addition, while the significance can be increased by considering multiple factors, it is important to understand the limits of the accuracy of this prediction.

Distribution of genes for bone morphogenetic protein-4, -6, growth differentiation factor-5, and bone morphogenetic protein receptors in the process of experimental spondylosis in mice

OBJECT

Because little is known about the molecular mechanisms underlying the process of spondylosis, the authors examined the extent of genetic localization of several members of bone morphogenetic protein (BMP) and BMP receptors in chondrogenesis during the process of inducing spondylosis in their previously established experimental mice model.

METHODS

Experimental spondylosis was induced in 5-week-old ICR mice. The cervical spine was harvested chronologically, and histological sections were prepared. Messenger RNA for BMP-4, growth and differentiation (GDF)-5, BMP-6, and BMP receptors (ALK-3, -6, and BMP-RII) was localized in the tissue sections by in situ hybridization. In the early stage, BMP-4-derived mRNA was localized mainly in cells in the anterior margin of the cervical discs, together with ALK-6 and BMP-RII mRNA. No GDF-5 and BMP-6 mRNA was detected at this stage. In the late stage, cells positive for BMP-4 decreased, whereas GDF-5 and BMP-6 mRNA were localized in cells undergoing chondrogenesis. The ALK-3 mRNA began to appear in this stage, as did ALK-6 and BMP-RII.

CONCLUSIONS

The localization of transcripts for BMP-4, -6, and GDF-5 as well as BMP receptors shown during the present experimental model indicate the possible involvement of molecular signaling by these BMPs in the chondrogenic progress in spondylosis.

A long-term follow-up study of cervical lesions in rheumatoid arthritis

To determine the natural history of cervical lesions in rheumatoid arthritis, 161 patients who had been followed for a minimum of 5 years were enrolled in this study. The average follow-up period was 10.2 years (range, 5 to 20 years). The severity of the rheumatoid arthritis was classified into three types based on the multiplicity of peripheral joint rheumatoid involvement: a least erosive subset, a more erosive subset, and a mutilating disease subset. Ninety-two patients (57%) had upper cervical involvement, which progressed in the order of anterior atlantoaxial subluxation, anterior atlantoaxial subluxation combined with vertical subluxation, and vertical subluxation alone. Subaxial subluxation was found in 18 patients (11%). In 17 of these 18 patients, upper cervical lesions were also noted. The incidence of cervical involvement in each disease subset was 39% in the least erosive group, 83% in the more erosive group, and 100% in the mutilating disease group. Fifty percent of the patients with cervical involvement had neck pain, and the remaining patients were asymptomatic. Neural involvement occurred in 10 patients. In 7 of these 10 patients, vertical subluxation of the atlas was responsible for the neural deficit. Six patients required surgical intervention because of progressive myelopathy.

Idiopathic spinal cord herniation: report of three cases and review of the literature

STUDY DESIGN

Three case reports and a literature review are presented.

OBJECTIVE

To describe characteristic clinical and radiographic findings of idiopathic spinal cord herniation.

SUMMARY OF BACKGROUND DATA

Idiopathic spinal cord herniation is a rare disease, with only 26 cases reported before the current study.

METHODS

Three cases of idiopathic spinal cord herniation are reported, and previous reports on this subject are reviewed.

RESULTS

The responsible regions were in the thoracic spine from T2 to T7. Symptoms were mainly unilateral muscle atrophy in the lower extremity and sensory disturbance below the thoracic level. These symptoms had been progressing gradually. Magnetic resonance imaging demonstrated a unique feature: The spinal cord shifted anteriorly in a few segments. Computed tomographic myelogram showed another distinctive picture: There was no subarachnoid space anterior to the spinal cord.

CONCLUSIONS

Because idiopathic spinal cord herniation is out of the concept of "compression myelopathy," this condition may be a pitfall in the diagnosis. Idiopathic spinal cord herniation should be recognized as one of the treatable causes for thoracic myelopathy.

Activating transcription factor 3 (ATF3) induction by axotomy in sensory and motoneurons: A novel neuronal marker of nerve injury

Activating transcription factor 3 (ATF3), a member of ATF/CREB family of transcription factors, is induced in a variety of stressed tissue. ATF3 regulates transcription by binding to DNA sites as a homodimer or heterodimer with Jun proteins. The purpose of this study was to examine the expression and regulation of ATF3 after axonal injury in neurons in dorsal root ganglia (DRG) and spinal cord. In naive rats, ATF3 was not expressed in the DRG and spinal cord. Following the cut of peripheral nerve, ATF3 was immediately induced in virtually all DRG neurons and motoneurons that were axotomized, and the time course of induction was dependent on the distance between the injury site and the cell body. Double labeling using immunohistochemistry revealed that the population of DRG neurons expressing ATF3 included those expressing c-jun, and in motoneurons ATF3 and c-jun were concurrently expressed after axotomy. In contrast to c-jun, ATF3 was not induced transsynaptically in spinal dorsal horn neurons. We conclude that ATF3 is specifically induced in sensory and motoneurons in the spinal cord following nerve injury and should be regarded as an unique neuronal marker of nerve injury in the nervous system.

Cervical radiculopathy and myelopathy: when and what can surgery contribute to treatment?

Indications and timing of surgical treatment for cervical radiculopathy and myelopathy, and the long-term results for the conditions, were reviewed. Advances in spinal imaging and accumulation of clinical experience have provided some clues as to indications and timing of surgery for cervical myelopathy. Duration of myelopathy prior to surgery and the transverse area of the spinal cord at the maximum compression level were the most significant prognostic parameters for surgical outcome. Thus, when myelopathy is caused by etiological factors that are either unchangeable by nature, such as developmental canal stenosis, or progressive, such as ossification of the posterior longitudinal ligament, surgical treatment should be considered. When an etiology of myelopathy is remissible, such as soft disc herniation and listhesis, surgery may be reserved until the effects of conservative treatment are confirmed. When surgery is properly carried out, long-term surgical results are expected to be good and stable, and the natural course of myelopathy secondary to cervical spondylosis may be modified. However, little attention has been paid to the questions "When and what can surgery contribute to treatment of cervical radiculopathy?". A well-controlled clinical study including natural history should be done to provide some answers.

Peripheral nerve palsies in victims of the Hanshin-Awaji earthquake

On January 17, 1995, the Hanshin-Awaji earthquake directly hit a metropolis and destroyed approximately 120,000 houses. Many people were buried under the debris of the Japanese style wooden houses or were injured by falling furniture. Twenty-five patients (35 extremities) with earthquake associated peripheral nerve palsy were studied and followed up for 2 years. The characteristic feature of earthquake associated palsies was combined nerve palsy induced by prolonged compression. There were 11 extremities with brachial plexus palsy; two extremities with combined radial, median, and ulnar nerve palsy; two extremities with combined median and ulnar nerve palsy; two extremities with radial nerve palsy; two extremities with ulnar nerve palsy; 10 extremities with combined femoral and sciatic nerve palsy; one extremity with combined tibial and peroneal nerve palsy; and five extremities with compartment syndrome of the leg. Many peripheral nerve palsies were induced by nerve ischemia. Most patients had good spontaneous recovery. The prognosis of these palsies generally was good.

Can intramedullary signal change on magnetic resonance imaging predict surgical outcome in cervical spondylotic myelopathy?

STUDY DESIGN

A retrospective study evaluating magnetic resonance imaging, computed tomographic myelography, and clinical parameters in patients with cervical spondylotic myelopathy.

OBJECTIVES

To investigate whether magnetic resonance imaging can predict the surgical outcome in patients with cervical spondylotic myelopathy.

SUMMARY OF BACKGROUND DATA

No previous studies have established whether areas of high signal intensity in T2-weighted magnetic resonance images can be a predictor of surgical outcomes.

METHODS

Fifty patients with cervical spondylotic myelopathy were examined by magnetic resonance imaging and computed tomographic myelography before surgery and by delayed computed tomographic myelography after surgery. The correlation between the recovery rate and the clinical and imaging parameters was analyzed.

RESULTS

The best prognostic factor was the transverse area of the spinal cord at maximum compression (correlation coefficient, R = 0.58). The presence of high signal intensity areas on T2-weighted magnetic resonance images correlated poorly with the recovery rate (R = -0.29). However, patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poor surgical results associated with muscle atrophy in the upper extremities. Postoperative delayed computed tomographic myelography showed that multisegmental areas of high signal intensity on T2-weighted magnetic resonance images probably represent cavitation in the central spinal cord.

CONCLUSIONS

Patients with multisegmental areas of high signal intensity on T2-weighted magnetic resonance images tended to have poorer surgical results. However, the transverse area of the spinal cord at the level of maximum compression was a better prognostic indicator.

Pathology of ossification of the posterior longitudinal ligament and ligamentum flavum

Ossification takes place in the posterior longitudinal ligament and ligamentum flavum of the spine under certain conditions of unknown nature. Ossification of these ligaments has the following characteristics: (1) ectopic bone formation occurring within the spinal ligaments; (2) ossification accompanies ligamentous tissue hyperplasia and cell proliferation; (3) before ossification, fibrocartilaginous cell proliferation, calcification and tissue resorption with vascular ingrowth take place sequentially; (4) ossification of the ligament has a specific site of predilection and often occurs in combination with senile ankylosing vertebral hyperostosis (Forestier's disease) or diffuse idiopathic skeletal hyperostosis; and (5) ossification and symptom development are remarkably more frequent in the Japanese population. Recent studies revealed that bone morphogenetic proteins and transforming growth factor-beta played an important role in the matrix hyperplasia and ossification of the spinal ligament, and metabolic and genetic aberration often characterized patients suffering from this disorder.

A clinico-pathological study of cervical myelopathy in rheumatoid arthritis: post-mortem analysis of two cases

Two patients who developed cervical myelopathy secondary to rheumatoid arthritis were analyzed post mortem. One patient had anterior atlanto-axial subluxation (AAS) combined with subaxial subluxation (SS), and the other had vertical subluxation (VS) combined with SS. In the patient with AAS, the posterior aspect of the spinal cord demonstrated severe constriction at the C2 segment, which arose from dynamic osseous compression by the C1 posterior arch. A histological cross-section of the spinal cord at the segment was characterized by distinct necrosis in the posterior white columns and the gray matter. In the patient with VS, the upper cervical cord and medulla oblongata showed angulation over the invaginated odontoid process, whereas no significant pathological changes were observed. At the level of SS, the spinal cord was pinched and compressed between the upper corner of the vertebral body and the lower edge of the lamina. Histologically, demyelination and gliosis were observed in the posterior and lateral white columns.

Rapid decalcification using microwaves for in situ hybridization in skeletal tissues

In situ hybridization histochemistry is the sole tool available for detecting the localization and expression of specific RNA on histological sections under various in vivo conditions. For this paper, we examined the effect of microwave exposure on the time needed for decalcification of skeletal tissues and on the preservation of sensitivity for hybridization signals. Our data show that the use of microwave decalcification reduces the decalcification period while preserving intense hybridization signals for mouse alpha1 chain of procollagen type I mRNA in osteogenic cells in bone. The use of microwave treatment to decalcify skeletal tissues may prevent delay in obtaining experimental results or the loss of signals during in situ hybridization.

Pathological fracture of a lumbar vertebra caused by rheumatoid arthritis--a case report

We describe a case of rheumatoid arthritis (RA) with collapse of the L3 lumbar vertebra for which surgery was performed. The pathogenesis of lumbar lesions affected by RA is discussed and the literature reviewed.

Cervical lesions related to the systemic progression in rheumatoid arthritis

STUDY DESIGN

Cross-sectional study of cervical involvement in rheumatoid arthritis.

OBJECTIVES

To clarify the correlation between the deterioration of cervical lesions and the systemic progression of rheumatoid arthritis.

SUMMARY OF BACKGROUND DATA

The natural course of cervical lesions varies. To date, no systemic parameter has been clarified to predict the progression.

METHODS

One hundred seventy-three patients with rheumatoid arthritis participated in this study. The authors studied the progression of cervical lesions and investigated the relation between the types of cervical subluxation at the end of study and the following four variables: the serum level of C-reactive protein, the number of joints with erosion, carpal height ratio, and disease subset (least erosive subset, more erosive subset, and mutilating disease subset).

RESULTS

Of the 173 patients, 55 already had cervical subluxation before entering the study. During the follow-up period, 44 patients deteriorated radiographically, and 77 (45%) had cervical involvement, including involvement of upper cervical lesions in 65 patients, upper lesions combined with subaxial subluxation in 10, and subaxial subluxation alone in 2. The upper cervical subluxation progressed in the order of anterior atlantoaxial subluxation, atlantoaxial subluxation combined with vertical subluxation, and vertical subluxation alone. Deterioration of upper cervical lesion and occurrence of subaxial subluxation were closely correlated with an elevation of serum C-reactive protein level, an increase in the number of joints with erosion, and a decrease in the carpal height ratio. The incidence of cervical involvement and the extent of deterioration were different among the disease subsets.

CONCLUSIONS

The serum level of C-reactive protein, the number of joints with erosion, and the carpal height ratio correlated closely with the extent of the cervical subluxation. The average C-reactive protein values during the follow-up period correlated with progression of the cervical lesions. The classification of rheumatoid disease subset was useful for predicting the terminal feature of the cervical lesions.

Long-term follow-up results of laminectomy for cervical myelopathy caused by ossification of the posterior longitudinal ligament

OBJECT

This retrospective study was performed to assess the long-term results of cervical laminectomy in treating ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

METHODS

The authors reviewed medical records in 44 of 52 patients who underwent cervical laminectomy between 1970 and 1985 (mean follow up 14.1 years). The neurological recovery rate after laminectomy was 44.2% after 1 year and 42.9% after 5 years. The surgical outcome was maintained after 5 years but worsened between 5 and 10 years postsurgery: the recovery rate at the last follow-up review was 32.8%. Using multivariate stepwise analysis, the preoperative factors that affected clinical results were found to be the age at operation, the severity of preexisting myelopathy, and a history of trauma. Late neurological deterioration was observed in 10 (23%) of 44 patients. The earliest deterioration occurred at 1 year and the latest was at 17 years postsurgery (mean 9.5 years). The most frequent cause of deterioration was trauma due to a fall (six patients), followed by ossification of the ligamentum flavum (three patients). Postoperative spread of the OPLL was noted in 70% of the patients, but it was clearly the cause of neurological deterioration in only one of them. After laminectomy, postoperative progression of kyphotic deformity was observed in 47% of patients, but these changes did not cause neurological deterioration.

CONCLUSION

The authors recommend early surgical decompression for OPLL because the outcome is better for younger patients and for those with a higher score as measured by the Japanese Orthopedic Association's system.

Switch of osteonectin and osteopontin mRNA expression in the process of cartilage-to-bone transition during fracture repair

The process of cartilage-to-bone transition (CBT) is a key event for the achievement of rigid bone healing during fracture repair. Since mineralization of cartilaginous matrix is a prerequisite for the initiation of CBT, the genetic localization of mineralization-related bone matrix proteins in CBT was examined in this study. An in situ hybridization method used on decalcified sections with digoxigenin-11-UTP labelled probes identified the cellular localizations of these genes in CBT. Cessation of osteonectin mRNA together with induction of osteopontin mRNA in chondrocyte maturation was observed during the process of CBT in the fracture callus on day 12 after fracture; osteocalcin mRNA was absent in chondrocytes of the CBT area. Induction of osteopontin mRNA in maturated chondrocytes was followed by the expression of mRNAs for osteonectin, osteopontin and osteocalcin in osteogenic cells in the ossification front of CBT. The data suggest that the switch from osteonectin to osteopontin mRNA expression in chondrocyte maturation is one of the key events during CBT. Transcriptional disorders of the expression of these molecules may be linked to the failure of fracture repair, i.e. delayed or prevented hypertrophic osteosynthesis.

Natural history of upper cervical lesions in rheumatoid arthritis

The natural history of the upper cervical lesions in rheumatoid arthritis (RA) was investigated, based on a follow-up study of 79 patients. At the beginning of this study, anterior atlantoaxial subluxation (AAS) was found in 35 patients, AAS combined with vertical subluxation (VS) in 34, and VS alone in 10. During the follow-up period (mean, 6.4 years), these lesions deteriorated in 30 of the 79 patients. To evaluate the occipitoatlantoaxial relation, the angles between occiput and atlas (C0/C1 angle) and between atlas and axis (C1/C2 angle) were measured, and the correlation between these angles and deterioration of the lesions was investigated. The severity of RA was classified according to the "disease subset" advocated by one of us (T.O.): the least erosive subset (LES), the more erosive subset (MES), and the mutilating subset (MUD). There was a significant positive correlation between the C1/C2 angle and atlantodental interval (ADI) and a significant negative correlation between the C0/C1 angle and the ADI. This indicates that the atlas not only shifts forward but also slips down and forward at an incline from the axis. With an increase of the atlantal inclination, the anterior arch of atlas displaces in an anteroinferior direction, and VS combines with AAS. The development of associated VS lessens the amount of the ADI. At the advanced stage of the natural course, AAS is concealed, and VS alone is demonstrated. We concluded that the upper cervical lesion deteriorated in the order of AAS, AAS + VS, and VS alone. In patients classified as the LES subset, only AAS was found, and VS was never combined with AAS at the terminal stage. In patients in the MES, VS frequently combined with AAS. All patients who deteriorated to VS alone were ranked as MUD.

In vivo direct gene transfer into articular cartilage by intraarticular injection mediated by HVJ (Sendai virus) and liposomes

OBJECTIVE

To establish a system for efficient, direct in vivo gene transfer into joints.

METHODS

A hemagglutinating virus of Japan (HVJ; Sendai virus)-liposome suspension containing SV40 large T antigen (SVT) gene was injected intraarticularly into knee joints of 6-week-old female Lewis rats. Rats were killed at various times for immunohistochemical analysis of the expression of SVT gene.

RESULTS

The expression of SVT gene was detected immunohistochemically in chondrocytes in the superficial and middle zones of articular cartilage in the knee joints. The average percentage of SVT-positive cells was estimated to be approximately 30% on days 3, 7, 14, and 21 after transfection. Moreover, no pathologic change caused by HVJ-liposome injection was observed in the joints.

CONCLUSION

The transfection frequency and stability of expression recognized in this study indicate the possibility of a strategy for treatment of joint disorders, including arthritis, using direct gene transfer.

[The dorsal approach in degeneratively changed cervical spine]

The posterior approach to the cervical spine was the only method of access to the spinal canal until the anterior approach was developed by Robinson and Smith, and Cloward. With the accumulation of experience in posterior decompression for cervical spondylotic myelopathy (CSM), successful laminectomy was guaranteed only when lordotic alignment of the cervical spine, wide and extensive laminectomy for adequate posterior shift of the spinal cord, and stability of the spine were ensured after surgery. The thick scar formation occasionally seen subsequent to postlaminectomy hematoma could lead to an unfavorable outcome. The insertion of surgical instruments, such as a Kerrison rongeur or a curette, into the spinal canal without being aware of how narrow the canal is, or uneven decompression of the spinal cord during resection of the laminae can impinge on or distort the spinal cord and result in deterioration of neurological function. Several authors have pointed out that postoperative loss of neural function is a hazard of surgical intervention. Owing to the poor results of conventional laminectomy for cervical compression myelopathy related to the problems mentioned above, Kirita developed extensive simultaneous decompression laminectomy to avoid distortion of the spinal cord by the edges of the resected laminae. Hattori devised an expansive Z-shaped laminoplasty in which the posterior wall of the spinal canal was preserved by Z-plasty of the prepared laminae. This was an attempt to prevent the invasion of scar tissue, i.e., the so-called laminectomy membrane, which was believed to be a cause of late neurological regression. He also expected that the laminae reconstructed by Z-plasty would provide support for the spine. The introduction of high-speed air-drills allowed successful development of this procedure. In 1977, Hirabayashi introduced an epoch-making laminoplasty, the expansive open-door laminoplasty. He described the advantages of this procedure as: possibility of decompressing multiple levels of the spinal cord simultaneously, better postoperative support of the neck, allowing earlier mobilization of the patients, prevention of postoperative kyphotic deformity of the cervical spine, and reduced mobility of the cervical spine postoperatively, which helps to prevent late neurological deterioration and progression of OPLL. Subsequent to the Hirabayashi laminoplasty, various modifications and supplementary procedures have been devised for further improvement of the safety and efficacy of decompression, and for improved stability of the spine. Aims, advantages and disadvantages of laminoplasty: The aims of the laminoplasty are to expand the spinal canal, to secure spinal stability and to spare the protective function of the spine. Preservation of mobility of the spine is also a goal of this procedure for multiple level involvement. Decompression can be extended along the nerve root by facetectomy. Preservation of the posterior spinal structures permits reinsertion of the nuchal muscles and the spinal ligaments after they have been totally or partially detached. This prevents kyphosis or listhesis of the cervical spine, which often develops after laminectomy, particularly in subjects below 50 years of age. Reconstructive procedures for reattaching muscles and/or ligaments to the spinous processes are added to the laminoplasty, improving the dynamic or ligamentous stability of the spine.

[Posterior approach to the degenerative cervical spine]

The posterior approach to the cervical spine was the only method of access to the spinal canal until the anterior approach was developed by Robinson and Smith, and Cloward. With the accumulation of experience in posterior decompression for cervical spondylotic myelopathy (CSM), successful laminectomy was guaranteed only when lordotic alignment of the cervical spine, wide and extensive laminectomy for adequate posterior shift of the spinal cord, and stability of the spine were ensured after surgery. The thick scar formation occasionally seen subsequent to postlaminectomy hematoma could lead to an unfavorable outcome. The insertion of surgical instruments, such as a Kerrison rongeur or a curette, into the spinal canal without being aware of how narrow the canal is, or uneven decompression of the spinal cord during resection of the laminae can impinge on or distort the spinal cord and result in deterioration of neurological function. Several authors have pointed out that postoperative loss of neural function is a hazard of surgical intervention. Owing to the poor results of conventional laminectomy for cervical compression myelopathy related to the problems mentioned above, Kirita developed extensive simultaneous decompression laminectomy to avoid distortion of the spinal cord by the edges of the resected laminae. Hattori devised an expansive Z-shaped laminoplasty in which the posterior wall of the spinal canal was preserved by Z-plasty of the prepared laminae. This was an attempt to prevent the invasion of scar tissue, i. e., the so-called laminectomy membrane, which was believed to be a cause of late neurological regression. He also expected that the laminae reconstructed by Z-plasty would provide support for the spine. The introduction of high-speed air-drills allowed successful development of this procedure. In 1977, Hirabayashi introduced an epoch-making laminoplasty, the expansive open-door laminoplasty. He described the advantages of this procedure as: possibility of decompressing multiple levels of the spinal cord simultaneously, better postoperative support of the neck, allowing earlier mobilization of the patients, prevention of postoperative kyphotic deformity of the cervical spine, and reduced mobility of the cervical spine postoperatively, which helps to prevent late neurological deterioration and progression of OPLL. Subsequent to the Hirabayashi laminoplasty, various modifications and supplementary procedures have been devised for further improvement of the safety and efficacy of decompression, and for improved stability of the spine. Aims, advantages and disadvantages of laminoplasty: The aims of the laminoplasty are to expand the spinal canal, to secure spinal stability and to spare the protective function of the spine. Preservation of mobility of the spine is also a goal of this procedure for multiple level involvement. Decompression can be extended along the nerve root by facetectomy. Preservation of the posterior spinal structures permits reinsertion of the nuchal muscles and the spinal ligaments after they have been totally or partially detached. This prevents kyphosis or listhesis of the cervical spine, which often develops after laminectomy, particularly in subjects below 50 years of age. Reconstructive procedures for reattaching muscles and/or ligaments to the spinous processes are added to the laminoplasty, improving the dynamic or ligamentous stability of the spine.

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 person's 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.

Post-traumatic syringomyelia

STUDY DESIGN

This study retrospectively analyzed patients who developed post-traumatic syringomyelia secondary to spinal cord injury.

OBJECTIVES

To identify an indicator that would predict the outcome of surgical treatment for post-traumatic syringomyelia.

SUMMARY OF BACKGROUND DATA

Syrinx-subarachnoid shunting was chosen as a surgical treatment for post-traumatic syringomyelia. No previous study has been published concerning magnetic resonance imaging findings' ability to predict surgical results before surgery.

METHODS

Nine patients diagnosed by magnetic resonance imaging with post-traumatic syringomyelia were the subjects of this study. The magnetic resonance imaging findings and surgical results were analyzed.

RESULTS

Neurologic deterioration was found in five patients. Ascending dissociated sensory disturbances and motor weakness were noticed to occur characteristically above the level of the spinal cord injury. The other four patients complained of a slight worsening of numbness without displaying neurologic deterioration. The five patients with neurologic deterioration were treated with a syrinx-subarachnoid shunting. Two of the five patients experienced sustained neurologic improvement after a midline myelotomy, which allowed the fluid within the syrinx to spout out and cause the expanded spinal cord to collapse. This was called a "high-pressure syrinx." In these two patients, the preoperative magnetic resonance imaging demonstrated a positive flow-void sign. On the other hand, drainage of the syrinx in the three patients with a negative flow-void sign did not collapse the expanded spinal cord, and the surgical results were considered fair. This was called a "low-pressure syrinx."

CONCLUSIONS

Post-traumatic syringomyelia was classified into two types. A preoperative distinction could be made based on the presence or absence of the flow-void sign on a T2-weighted magnetic resonance image.

Expansive laminoplasty for cervical radiculomyelopathy due to soft disc herniation

STUDY DESIGN

A comparative study was performed in patients with cervical radiculomyelopathy due to soft disc herniation to compare surgical results of laminoplasty with anterior discectomy and arthrodesis.

OBJECTIVES

To determine whether posterior decompression without discectomy can be selected for cervical myelopathy due to cervical soft disc herniation.

SUMMARY OF BACKGROUND DATA

Anterior cervical discectomy and arthrodesis has had acceptable surgical results, but a significant number of complications have been reported, especially those related to bone grafting.

METHODS

Sixteen patients who received expansive laminoplasty and 17 patients who received anterior arthrodesis were studied. The mean value of the anteroposterior diameter of the spinal canal was 12.4 mm in the former and 12.9 mm in the latter. The mean follow-up was 3.1 years in the laminoplasty group, and 8.8 years in the anterior arthrodesis group. There was no statistical difference between the two groups in prognostic factors believed to affect surgical results. Neurologic results were evaluated with postoperative scores and recovery rates by methods previously described, and assessed by the Japanese Orthopaedic Association scoring system.

RESULTS

The difference between the two groups in the recovery rate and final Japanese Orthopaedic Association score was not statistically significant. Surgical complications were more frequent in the anterior arthrodesis group than in the laminoplasty group. Additional surgeries were performed in three cases (18%) in the anterior arthrodesis group: posterior wiring for delayed union and kyphotic deformity in two cases, and laminoplasty for deterioration of myelopathy in one case. Regression of herniated cervical disc after laminoplasty was confirmed by computed tomography or magnetic resonance imaging in six of eight cases (75%).

CONCLUSIONS

When the incidence of complications and the possibility of regression of herniated disc are taken into consideration, expansive laminoplasty can be selected for radiculomyelopathy due to cervical disc herniation.

Vertebral body replacement with a ceramic prosthesis for metastatic spinal tumors

STUDY DESIGN

This study retrospectively analyzed the clinical outcome of vertebral replacement surgery with our unique ceramic prosthesis for spinal metastases.

OBJECTIVES

To indicate the results of vertebral replacement surgery with a ceramic prosthesis.

SUMMARY OF BACKGROUND DATA

Spinal metastasis often involves the vertebral bodies, of which abnormal fracture causes intractable pain and paresis. For such conditions, laminectomy or irradiation can have no effect because they do not improve spinal stability. Autogenous bone or bone cement are not durable materials, and fatigue fracture of the implanted material occasionally occurs. We developed a simple prosthesis made of alumina ceramic, a bioinert material, to replace the affected vertebrae. There has not been such a large study to assess vertebral replacement surgery with a ceramic prosthesis.

METHODS

From 1972 to 1993, 90 ceramic prostheses were used in 84 patients with spinal metastasis, and the average follow-up period was 26.2 months. The primary tumor was thyroid cancer in 13 patients, breast cancer in 12, multiple myeloma in eight, renal cell cancer in eight, gastrointestinal cancer in eight, and lung cancer in eight. The clinical symptoms were assessed before and after surgery, and the maintenance of operative gain was investigated.

RESULTS

Pain relief was achieved in 94%, motor function improved in 81%, and ambulation recovered in 64%. There were no serious complications associated with the procedure, and the operative benefit was maintained until the terminal stage in the vast majority of patients.

CONCLUSIONS

In selected patients, vertebral replacement using our prosthesis proved to be a useful procedure, effectively managing the severe spinal pain or neurologic deficits associated with vertebral body destruction.

Intramedullary changes of the spinal cord in cervical spondylotic myelopathy

STUDY DESIGN

This study retrospectively reviewed magnetic resonance imaging and delayed computed tomography after myelography of cervical spondylotic myelopathy patients who needed surgical treatment.

OBJECTIVES

The purpose of this study is to clarify the meaning of high magnetic resonance intensity areas in cervical spondylotic myelopathy patients.

SUMMARY OF BACKGROUND DATA

There is no conclusion whether the high magnetic resonance signal intensity areas can be a predictor for surgical results or not.

METHODS

Thirty-one patients with cervical spondylotic myelopathy were examined with magnetic resonance imaging before surgery and delayed computed tomography after surgery. The presence or absence of high intensity areas in the spinal cord was compared with clinical symptoms and surgical outcomes.

RESULTS

Twenty-three (74%) of 31 patients showed high intensity areas in the spinal cord on the T2-weighted image. Among these 23 patients, 18 revealed bilateral intramedullary "snake eyes" enhancement in delayed computed tomography. The presence of high intensity areas did not correlate with the surgical outcomes. Patients with multisegmental (linear) high intensity areas frequently manifested muscle atrophy in upper extremities.

CONCLUSIONS

High intensity areas on T2-weighted magnetic resonance imaging were not correlated with the severity of myelopathy or surgical outcomes evaluated by the Japanese Orthopaedic Association score. Magnetic resonance imaging or delayed computed tomography in this study could not rule out the presence of white matter changes, including axonal loss or demyelination. Multisegmental (linear) high intensity areas on T2-weighted magnetic resonance imaging were associated with clinical evidence of extensive anterior horn cell and radiographic evidence of gray matter cavitation.

Postoperative cervical pseudomeningocele with herniation of the spinal cord

STUDY DESIGN

This is a report of a patient in whom spinal cord herniation into a pseudomeningocele resulted in progressive myelopathy.

OBJECTIVE

To describe the outcome of a 59-year-old man who visited Osaka University Hospital complaining of gait disturbance. He had undergone cervical laminectomy to resect a spinal cord tumor 14 years previously.

SUMMARY OF BACKGROUND DATA

Pseudomeningocele is an extremely rare condition and can be overlooked. In addition, cord herniation into the pseudomeningocele rarely can be diagnosed before surgical exploration. Our patient represents the first case we are aware of in which magnetic resonance imaging could clearly demonstrate not only the pseudomeningocele, but the herniation of the cord into the cyst.

METHODS

Magnetic resonance imaging was used for preoperative and postoperative investigation.

RESULTS

The pseudomeningocele was resected to improve the neurologic status of the patient. During the operation, the herniated cord was successfully reduced into the original subarachnoid space by the release of adhesion. Most symptoms subsided soon after surgery. Magnetic resonance imaging could delineate not only the cyst and cord herniation, but the medullary pathology. The distribution of high-intensity areas on T2-weighted images suggested the cord damage.

CONCLUSION

Magnetic resonance imaging revealed not only the cyst and cord herniation, but medullary pathology, too.

Distribution of the basic fibroblast growth factor and its receptor gene expression in normal and degenerated rat intervertebral discs

STUDY DESIGN

Using a rat spondylosis model, the distributions of cells expressing the basic fibroblast growth factor and its receptor were investigated in normal and degenerated intervertebral discs. Cell-proliferating activity in degenerated discs was also assessed.

OBJECTIVES

This study was conducted to determine whether basic fibroblast growth factor is related to intervertebral disc degeneration.

SUMMARY OF BACKGROUND DATA

Basic fibroblast growth factor stimulates proliferation and matrix synthesis of cultured intervertebral disc cells.

METHODS

Immunohistochemistry and in situ hybridization histochemistry were conducted to detect cells with basic fibroblast growth factor-like immunoreactivity and fibroblast growth factor receptor messenger RNA, respectively. Cell-proliferating activity was evaluated by AgNOR staining.

RESULTS

In degenerated discs, round chondrocytes with basic fibroblast growth factor-like immunoreactivity and fibroblast growth factor receptor messenger RNA are scattered instead of spindle-shaped cells in the normal anulus (normal anular cells), which are devoid of basic fibroblast growth factor-like immunoreactivity and fibroblast growth factor receptor messenger RNA. The proliferating activity of these chondrocytes is suggested to exceed that of normal anular cells.

CONCLUSION

Basic fibroblast growth factor is suggested to promote proliferation of chondrocytes in degenerated discs in an autocrine or paracrine manner. Basic fibroblast growth factor may be related to intervertebral disc degeneration as a proliferation-stimulating factor of chondrocytes that replace normal anular cells during disc degeneration.

Natural course of cervical spine lesions in rheumatoid arthritis

STUDY DESIGN

This study analyzed the natural course of cervical spine involvement in rheumatoid arthritis by serial radiographs.

OBJECTIVES

The purpose was to determine the pattern of progression of cervical spine lesions in rheumatoid arthritis and predictors for the extent of progression.

SUMMARY OF BACKGROUND DATA

Subluxation frequently occurs as a result of rheumatoid involvement of the cervical spine. It may be severe in patients with mutilans deformities in the hands and feet. The extent of progression in a given patient is still unpredictable.

METHODS

Serial cervical radiographs in 49 patients with rheumatoid arthritis were analyzed. The extent of progression was evaluated by rheumatoid arthritis subset defined previously, which reflected the final extent of joint erosion in this systemic disease and could be roughly classified during early stages of the disease.

RESULTS

In the upper cervical spine, reducible anterior atlantoaxial subluxation occurred first. Vertical subluxation of the axis appeared next. Irreducible change of preceding anterior atlantoaxial subluxation was a sign of the start of vertical subluxation. In subaxial lesion, subluxation occurred less frequently (22.4%) than upper cervical lesion (77.6%). The extent of progression was different with the rheumatoid arthritis subset. In the upper cervical spine, none of the subset with least erosive disease developed vertical subluxation, whereas 52% of the subset with more erosive disease and 88% of the subset with mutilating disease advanced to vertical subluxation. The extent of progression was well correlated with the number of joints with erosion. Subaxial subluxation was often seen and became irreducible in mutilating disease and more erosive disease, but not in least erosive disease.

CONCLUSIONS

A progressive pattern of the upper cervical subluxations was clarified. That is, upper cervical lesions progressed from reducible anterior atlantoaxial subluxation to irreducible anterior atlantoaxial subluxation with vertical subluxation. This extent of progression was different with the rheumatoid arthritis subset, which was also related to the development of subaxial subluxation. The most aggressive arthritis classification, a subset with mutilating disease, had the more severe subluxation in both upper and subaxial cervical spine.

Orthopaedic management of spinal metastases

Spinal metastases result in severe spinal pain, neurologic deficits, or both. These symptoms usually are caused by spinal instability, in which conservative therapy can have no effect, and surgical treatment is required to restabilize the destroyed spinal segments. Surgical indications are instability of the spine, pain and/or paresis resistant to radiation therapy, acute progressing paresis, and unknown histologic diagnosis. There are 2 surgical approaches for vertebral metastases: prosthetic replacement and posterior stabilization. Single or 2 consecutive diseased vertebrae should be treated with replacement surgery. In this series, excellent surgical outcome was attained with this procedure, and surgical benefit was maintained until the terminal stage of each patient. Multiple vertebral metastases are treated with posterior stabilization using various instrumentation systems that provide rigid stabilization. To choose the most appropriate procedure for each patient, the local condition of the lesion and general status of the patient, including prediction of life expectancy, should be evaluated fully. Spinal metastases develop early and are not terminal events. Therefore, not only palliative treatment but also surgical intervention should be considered for spinal metastases when indicated.

Magnetic stimulation of biceps after intercostal cross-innervation for brachial plexus palsy. A study of motor evoked potentials in 25 patients

We studied the motor evoked potentials (MEP) in the biceps of 25 patients with traumatic brachial plexus palsy from root avulsion after cross-innervation by intercostal nerves. We used transcranial, transcervical and transthoracic magnetic stimulation at 8 to 235 months (mean 51) after transfer of intercostal nerves to the musculocutaneous nerve. Biceps strength recovered to MRC grade 2 in eight patients, grade 3 in three and grade 4 in 14. The mean latency of the MEP in the normal biceps on transcranial stimulation was 12.5 +/- 1.3 ms and on transcervical stimulation 6.3 +/- 1.1 ms. After intercostal reinnervation the mean latency on transcranial stimulation was 21.7 +/- 4.5 ms and on transthoracic stimulation 11.6 +/- 3.8 ms. The latency of the biceps MEP after reinnervation by intercostal nerves on transcranial and transthoracic magnetic stimulation correlated well with the duration of follow-up and the latency of the MEP on transthoracic magnetic stimulation correlated significantly with muscle power.

Magnetic stimulation of biceps after intercostal cross-innervation for brachial plexus palsy. A study of motor evoked potentials in 25 patients

We studied the motor evoked potentials (MEP) in the biceps of 25 patients with traumatic brachial plexus palsy from root avulsion after cross-innervation by intercostal nerves. We used transcranial, transcervical and transthoracic magnetic stimulation at 8 to 235 months (mean 51) after transfer of intercostal nerves to the musculocutaneous nerve. Biceps strength recovered to MRC grade 2 in eight patients, grade 3 in three and grade 4 in 14. The mean latency of the MEP in the normal biceps on transcranial stimulation was 12.5 +/- 1.3 ms and on transcervical stimulation 6.3 +/- 1.1 ms. After intercostal reinnervation the mean latency on transcranial stimulation was 21.7 +/- 4.5 ms and on transthoracic stimulation 11.6 +/- 3.8 ms. The latency of the biceps MEP after reinnervation by intercostal nerves on transcranial and transthoracic magnetic stimulation correlated well with the duration of follow-up and the latency of the MEP on transthoracic magnetic stimulation correlated significantly with muscle power.