Preoperative Scoring System for Prediction of Early Adjacent Vertebral Body Fracture After Balloon Kyphoplasty Using X-Rays Taken in a Non-Weight-Bearing Position.

BACKGROUND: Prevention of adjacent vertebral body fracture (AVF) following balloon kyphoplasty (BKP) is a key challenge. The objective of this study was to develop a scoring system that could be more extensively and effectively used to determine the surgical indications for BKP. METHODS: The study involved 101 patients aged 60 years or older who had undergone BKP. Logistic regression analysis was used to identify risk factors for early AVF within 2 months following BKP. Scoring was based on the odds ratio for risk factors, and cut-off values were determined from the receiver operating characteristics curve. The correlation between the total scores and the incidence of early AVF, and the area under the curve for the logistic regression model predicting early AVF using the scoring system were investigated. RESULTS: 29 cases (28.7%) experienced early AVF after BKP. The scoring system was created as follows: 1) age (<75 years: 0 points (P), ≥75 years: 1P), 2) number of previous vertebral fractures (0: 0P, 1 or more: 2P), and 3) local kyphosis (<7°: 0P, ≥7°: 1P). The total scores were found to be positively correlated with the incidence of early AVF (r = 0.976, P = 0.004). The area under the curve of the scoring system for predicting early AVF was 0.796. The incidence of early AVF was 4.2% at ≤1P and 44.3% at ≥2P (P < 0.001). CONCLUSIONS: A scoring system which can be applied to a broader patient population was developed. In cases where the total score is 2P or more, alternatives to BKP should be considered.

The Relationship Between Global Sagittal Balance and the Incidence of Early Adjacent Vertebral Fractures Following Balloon Kyphoplasty.

BACKGROUND: Recently, it is widely known that global sagittal balance (GSB) influences the postoperative outcome of the spine. The purpose of this study was to investigate the relationship between GSB and the incidence of early adjacent vertebral fracture (AVF) following balloon kyphoplasty (BKP). METHODS: This study included 96 patients (19 males, 77 females, mean age 77.4 ± 5.5 years) who underwent BKP for osteoporotic vertebral fracture and who were over 60-years-old. We investigated the effect of GSB on early AVF within 2 months after surgery. Of the 96 patients, 76 patients (16 males, 60 females, mean age 77.0 ± 5.4) underwent BKP at the thoracolumbar junction (T11-L2) and were investigated independently. After the two-group comparison, logistic regression analysis was performed. RESULTS: During the observation period (18.3 ± 14.7 months), 27 of 96 patients (28.1%) suffered AVF after BKP, and 24 of 96 patients (25.0%) suffered early AVF. In the logistic regression analysis, spinopelvic parameters were not detected as significant risk factors. In cases of BKP at the thoracolumbar junction (T11-L2), 24 of 76 patients (31.6%) suffered AVF after BKP during the observation period (15.3 ± 19.5 months), and 21 of 76 patients (27.6%) suffered early AVF. Logistic regression analysis detected pelvic tilt (PT): odds ratio 1.087 (P = 0.046∗) and local kyphosis: 1.147 (P = 0.003∗) as risk factors for early AVF. The cutoff value was PT≥29° from the receiver operating characteristics curve. CONCLUSIONS: At the thoracolumbar junction (T11-L2), PT ≥29° is one of the risk factors of early AVF following BKP.

Preoperative scoring system for predicting early adjacent vertebral fractures after Balloon Kyphoplasty.

BACKGROUND: Adjacent vertebral fracture (AVF) is a major complication following Balloon Kyphoplasty (BKP). There is no scoring system for predicting AVF using only preoperative elements. The purposes of this study were to develop a scoring system for predicting early AVF after BKP based on preoperative factors and to investigate the appropriate surgical indication for BKP. METHODS: Of 220 patients who underwent BKP at a single institution since 2011, 65 patients over the age of 60 who had undergone a standing whole spine X-ray preoperatively were enrolled. Factors affecting the occurrence of early AVF were examined. A scoring system was created consisting of the factors exhibiting significant differences, and the correlation between the total score and the incidence of early AVF was investigated. RESULTS: Twenty of the 65 patients (30.8%) had early AVF. In a univariate analysis, age, previous vertebral fracture, pelvic tilt, and Local kyphosis significantly influenced early AVF. In a multivariate logistic regression analysis, age had an odds ratio of 1.136 (95% CI 1.001-1.289), previous vertebral fractures 4.181 (1.01-17.309), and Local kyphosis 1.103 (1.021-1.191). The scoring system was set as follows: ①Age (<75 years: 0 points(P), 75years≦: 1P), ②The number of previous vertebral fractures (0: 0 P, 1: 1P, 2: 2P, 3 or more: 3P), and ③Local kyphosis (<10°: 0P, 10°â‰¦: 1P). There was a correlation between the total score and the incidence of early AVF (r = 0.812, ∗P = 0.05). The incidence of early AVF was 6.4% (2 cases/31 cases) for a score of ≦1P and 54.5% (18 cases/33 cases) for a score of ≧2P. CONCLUSIONS: There was a correlation between the total score and the incidence of early AVF. A score of 1 point or less may represent the appropriate surgical indication for BKP.

Factors Influencing Interbody Cage Subsidence Following Anterior Cervical Discectomy and Fusion.

STUDY DESIGN: This is a prospective study. OBJECTIVE: The purpose of this study was to analyze the factors influencing subsidence following anterior cervical discectomy and fusion (ACDF) using a stand-alone cage. SUMMARY OF BACKGROUND DATA: The relationship between cage subsidence and cage height and material has been reported in previous studies. METHODS: Clinical and radiologic data from 78 patients, 105 levels, undergoing single-level and 2-level ACDF without plates from 2007 to 2015 were collected prospectively. Patients were followed for at least 12 months after surgery. Radiographs were obtained preoperatively, at 1 week, and at 1, 3, 6, and 12 months postoperatively to determine the presence of fusion and cage subsidence. RESULTS: There was a correlation in cage height and subsidence (Spearman P<0.05). Cage subsidence was significantly shorter in the polyetheretherketone cages than in titanium cages (P<0.05). However, when cage height was <5 mm, the difference between the 2 groups was not significant. Large subsidence (>3 mm) was observed in 17 patients, 20 levels, many of whom exhibited sinking in the first month after surgery. CONCLUSIONS: The greater the cage height, the greater the risk of cage subsidence in ACDF. Polyetheretherketone cages are superior to titanium cages for the maintenance of intervertebral height in cases where cage height is >5.5 mm. LEVEL OF EVIDENCE: Level 3.

Compensatory mechanism of the spine after corrective surgery without lumbar-sacral fixation for traumatic thoracolumbar kyphotic spine deformity.

BACKGROUND: It remains unclear whether long fusion including lumbar-sacral fixation is needed in corrective surgery to obtain good global sagittal balance (GSB) for the treatment of traumatic thoracolumbar kyphotic spine deformity. The purposes of this study were to evaluate compensatory mechanism of the spine after corrective surgery without lumbar-sacral fixation and to evaluate the parameters affecting the achievement of good GSB post-operatively. METHODS: Twenty (20) subjects requiring corrective surgery (distal end of fixation was L3) were included in this study. The radiographic parameters were measured pre-operatively and at one month after surgery. Sagittal Vertical Axis (SVA), Lumber Lordosis angle altered by fracture (fLL), Thoracic Kyphosis angle altered by fracture (fTK), Pelvic Tilt (PT), Sacral Slope (SS), Pelvic Incidence (PI), Segmental Lumbar Lordosis (sLL: L3-S/L4-S), and local kyphotic angle were measured. The correlation between correction of local kyphotic angle (CLA) and the change in radiographic parameters was evaluated. Post-operatively, subjects with SVA<50 mm and PI-fLL<10°were regarded as the "good GSB group (G group). The radiographic parameters affecting the achievement of G group were statistically evaluated. RESULTS: fLL, sLL:L3-S and sLL:L4-S were decreased indirectly because the local kyphosis was corrected directly (CLA: 26.5 ± 8.6°) (P < 0.001). CLA and the change in fLL showed significant correlation (r = 0.821), the regression equation being: Y = -0.63X+3.31 (Y: The change in fLL, X: CLA). The radiographic parameters significantly affecting the achievement of G group were: SVA, PT, PI-fLL, sLL: L3-S, and sLL: L4-S (P < 0.01). CONCLUSION: The main compensatory mechanism was the decrease of lordosis in the lumbar spine. fLL was decreased to approximately 60% of CLA after surgery. SVA was not corrected by the compensatory mechanism.

Prevalence and risk factors of deep vein thrombosis in patients undergoing lumbar spine surgery.

BACKGROUND: Spinal surgery is classified as a moderate risk for DVT. The occurrence of DVT after various spinal surgical procedures was reviewed retrospectively, and the perioperative risk factors in the high-risk group were identified. In addition, the administration of the factor Xa inhibitor to DVT subjects with unstable thrombosis was evaluated to reveal its effectiveness in the prevention of PTE and postoperative complications. METHODS: This study included 588 subjects who underwent lumbar spine surgery. The patient population consisted of the following four groups: the fracture group (F group), the laminectomy group (La group), the TLIF group (T group), and the long fusion group (Lo group). Bilateral lower limb venous ultrasonography was performed on the day before surgery, the day after surgery, and one week after surgery. The incidence of DVT was determined for each group and potential risk factors were evaluated in the group with the highest incidence of DVT. Subjects with DVT who had unstable thrombosis received anticoagulant therapy (factor Xa inhibitor) and their treatment results were assessed. RESULTS: The overall incidence of DVT was 32.3% (190/588). A significantly high incidence of DVT was observed in the Lo group (54.3%; 75/138). Logistic regression and ROC analysis of potential risk factors in the Lo group identified a D-dimer value of 19.5 ug/ml at one week postoperatively as a risk factor of DVT (p = 0.02; odds ratio, 4.09; 95% CI, 2.82-7.88). Overall, 15.8% of subjects (30/190) received anticoagulant therapy. These subjects experienced neither PTE nor epidural hematoma. A follow-up ultrasonography performed at three weeks postoperatively detected the disappearance/resolution of DVT in 86.7% of these subjects (26/30). CONCLUSION: The incidence of DVT varied according to the invasiveness of the procedure. Successful management of DVT hinges on preoperative risk management involving prophylactic treatment and early diagnosis, in order to avoid PTE and other complications.

Risk Factors of Adjacent Segment Disease After Transforaminal Inter-Body Fusion for Degenerative Lumbar Disease.

STUDY DESIGN: A retrospective study. OBJECTIVE: The purpose of this study was to determine the incidence and risk factors of adjacent segment disease (ASD) after transforaminal inter-body fusion (TLIF) for degenerative lumbar disease. SUMMARY OF BACKGROUND DATA: ASD is a major complication after spinal fusion. Many reports have been published concerning the risk factors for ASD after TLIF. A number of quantitative relationships to spino-pelvic parameters have been established. A retrospective cohort study was carried out to investigate spino-pelvic alignment in patients with ASD after TLIF. METHODS: This study evaluated 263 subjects (150 subjects undergoing floating fusion (FF group), and 113 patients undergoing lumbosacral fusion (LF group)) who underwent TLIF from 2009 to 2012. The mean follow-up period was 37.6 months. Several parameters were measured using pre- and postoperative full-length free-standing radiographs, including lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI), pelvic tilt (PT), and PI-LL. Multivariate logistic regression analysis was performed to evaluate these parameters as potential risk factors of early onset radiographic ASD. RESULTS: Radiographic ASD was found in 65 cases (43.3%) in the FF group, and 49 cases (43.3%) in the LF group. LL improved by 7.5° and 3.9° in each group respectively after TLIF. However, PT worsened by 6.4° in the LF group. When comparing with ASD positive cases and ASD negative cases, a significant difference in preoperative PT was observed in both FF (P = 0.001) and LF groups (P = 0.0001). Logistic regression analysis and receiver operating characteristic analysis revealed that preoperative PT of more than 22.5° was a significant risk factor of the incidence of ASD after TLIF (P = 0.02; odds ratio: 5.1, 95% CI: 1.62-9.03). CONCLUSION: Patients with preoperative sagittal imbalance have a statistically significant increased risk of ASD. The risk of ASD incidence was 5.1 times greater in subjects with preoperative PT of more than 22.5°.

Evaluation of biomechanical and histological features of vertebrae following vertebroplasty using hydroxyapatite blocks.

Vertebroplasty was performed using hydroxyapatite blocks to examine the course of compressive strength and histological features in a dog model. The vertebral fracture model was prepared by punching a hole in the center of the vertebra and at 4 sites around the vertebra (5 holes in total) from the front side of the vertebra using an air drill and hollowing the holes. Measurements were made on healthy vertebrae, vertebrae from the vertebral fracture model, vertebrae removed from animals immediately after vertebroplasty, vertebrae collected 1 and 2 months after vertebroplasty, and vertebrae untreated for 1 month after vertebral fracture. Histological examinations were also performed 1 and 2 weeks and 1 and 2 months after vertebroplasty with hydroxyapatite blocks. The strength of vertebrae in the fracture model immediately after vertebroplasty was significantly higher than that in the untreated fracture, and the strength of vertebrae 1 month after the procedure was equivalent to that of healthy vertebrae. Histologically, new bone formation was found around hydroxyapatite blocks 2 weeks after the procedure, and strong crosslinking between neighboring hydroxyapatite blocks was found after 1 month.These results suggest that hydroxyapatite blocks may be effective as filling material for vertebral fracture from both biomechanical and histological perspectives.

Impact of passive smoking on the bones of rats.

Many epidemiological surveys have identified smoking as a risk factor for osteoporosis, but it is unclear whether smoking has a direct effect on bone metabolism and if such an effect could cause osteoporosis. Therefore, we examined whether smoking causes osteoporosis based on the impact of smoke exposure on the bones of rats. A rat model of passive cigarette smoking was prepared by breeding rats in a cigarette-smoking box for 4 or 8 weeks. Histological changes, micro-computed tomographic (CT) analysis, mechanical bone strength, and bone mineral density of the femur and lumbar vertebrae were examined in these rats and in control rats that were not exposed to smoke. Lower mechanical bone strength was observed in smoke-exposed rats, but these differences were not significant. Significantly lower bone mineral density was found in the femur (P<.01) and lumbar bones (P<.001) of 8-week smoke-exposed rats compared to controls. In a micro-CT scan of lumbar vertebrae, the bone volume, trabecular thickness, trabecular number, and trabecular separation differed significantly between smoke-exposed rats and controls. Histologically, the osteocytes in the smoke-exposed rats were small (approximately 25% of the size in controls), and decreased numbers of marrow cells and osteoblasts (P<.01), as well as a black carbon dust-like substance, were found in the bone of smoke-exposed rats. These results indicate that smoking significantly decreases bone mineral density, which causes osteoporosis, and the organizational changes in the bone suggest a direct effect of smoking on bone structure. Fewer marrow cells were present in the smoke-exposed rats, and a black carbon dust-like substance was observed.

Clinical course and significance of the clear zone around the pedicle screws in the lumbar degenerative disease.

STUDY DESIGN: A retrospective study. OBJECTIVE: To report the clinical course and significance of postoperative radiolucent zones around pedicle screws. SUMMARY OF BACKGROUND DATA: Radiolucent zones around pedicle screws have been considered to indicate loss of fixation, delayed union, or pseudarthrosis. Few reports have described the course and significance of them. METHODS: Plain radiographs were evaluated from 190 patients with pedicle screw fixation. When 1 mm or greater circumferential lucency was confirmed around a screw on plain radiographs from 2 or more directions, the patient was judged as clear-zone positive. The course of clear-zone positivity was investigated and the relationships between clear-zone positivity and the following items were investigated: (1) number of levels fused, (2) bone union, (3) posterolateral lumbar fusion versus posterior lumbar interbody fusion, (4) clinical results, (5) bone mineral density, and (6) screw types. RESULTS: Although clear zones were observed in 78 patients 6 months after surgery, the clear zone-positive rate decreased over time and the progression of bone union and the number of patients decreased to 28 at the final follow-up 3 years or more after surgery. Interobserver and intraobserver coefficient of variability in clear-zone judgment was over 0.86, and agreement was over 96%. At final follow-up, pseudarthrosis was found in 15 patients. Although the predictive value of the positive test for the presence of clear zones for pseudarthrosis at final follow-up was 0.50, sensitivity was 0.93 and specificity was 0.92. There were significant differences in the clear zone-positive rate in the number of levels fused and bone mineral density among the investigated items. CONCLUSION: As approximately two thirds of the clear zones disappeared over time, the presence of clear zones did not necessarily mean pseudarthrosis. However, clear zones persisting for 2 years or longer after surgery are a great risk of pseudarthrosis. Therefore, careful observation of clear zones around pedicle screws is of great significance as an evaluation of bone union.

A comparative study for wide excision of malignant tumors distal to S2.

BACKGROUND AND AIM: We conducted a retrospective study comparing 5 patients (Group A) who underwent posterior excision of tumors distal to S2 using a modified threadwire saw (MT-saw) with 5 similar patients (Group B) who underwent tumor excision using chisels and airtomes. PATIENTS AND METHODS: The data of 10 patients were obtained from intra-operative records. A flexible silver guide probe connected to an MT-saw by a suture thread was devised for use in osteotomy passing through the S1 sacral canal in the lateral sacrum. Operative time, blood loss and excisional margins were compared between the two groups. RESULTS: Group A had a shorter average operative time (2 hours 24 minutes) and smaller average blood loss (2,124.6 ml) than Group B. In Group A, one patient incurred an S1 nerve root injury, and all patients had wide histological margins. In Group B, one patient had an S1 nerve root injury and another tumor contamination due to a fracture. CONCLUSION: The MT-saw greatly facilitated lateral sacral osteotomy and reduced the risk of tumor cell spread, permitting faster, safer excision with a wider margin.

Current trends in bone grafting and the issue of banked bone allografts based on the fourth nationwide survey of bone grafting status from 2000 to 2004.

BACKGROUND: The Japanese Orthopaedic Association Committee on Tissue Transplantation and Regenerative Medicine has conducted a nationwide survey of the status of bone grafting in Japan every 5 years from 1985. We report here the status of bone grafting from 2000 to 2004, show the trends in bone grafting from 1985 to 2004, and draw attention to the issues affecting banked bone allografts. METHODS: Questionnaires devised by the Committee were sent to all educational and training hospitals (2239 institutions) approved by the Japanese Orthopaedic Association. RESULTS: Survey responses were obtained from 1263 institutions (56%). Of these, 875 institutions performed tissue transplantation during this period. A total of 163 564 tissue transplantations were performed, and 134 782 (82.4%) of them were bone grafts. Of the bone grafts, 76 015 (56.4%) were autografts, 53 735 (40%) used a synthetic bone substitute, and 4886 (3.6%) were banked bone allografts. The proportion of synthetic bone substitutes increased, and the proportion of autografts decreased year by year. Synthetic bone substitutes were most frequently used for replacement arthroplasty (31%). Fifty percent of banked bone allografts were performed for joint disorders requiring replacement arthroplasty. During this period, 271 institutions performed banked bone allografts, with 210 preserving allografts in their own institutions. Donor selection criteria, processing and preservation methods, and management of the bone bank were not the same in all banks. CONCLUSIONS: Most bone grafts performed in Japan during the four surveys were still autografts. However, the proportion of autografts decreased, and the proportion of synthetic bone substitutes increased. The number of synthetic bone substitutes and banked bone allografts used for replacement arthroplasty increased significantly. However, the total number of banked bone allografts reported in the fourth survey was still low. Quality control of banked bone allografts and management of bone banks were not satisfactory, although they were improved.

Extensor retinaculum graft for chronic boxer's knuckle.

PURPOSE: Boxer's knuckle is a tear of the metacarpophalangeal (MCP) joint capsule that occurs while punching. Because of the nature of boxing, boxer's knuckle tends to be a chronic condition and often is associated with sagittal band rupture. Chronic cases often feature excessive scarring in the damaged area where the sagittal band and the MCP joint capsule become indistinguishable. The purpose of this study was to ascertain whether extensor retinaculum grafting to the defect is useful in treating chronic boxer's knuckle when direct repair of a capsular tear is not possible. METHODS: In 5 professional boxers with chronic boxer's knuckle in whom capsular repair could have impaired MCP joint flexion, scar tissue of the damaged capsule and the sagittal band-if ruptured-were removed and an oval extensor retinaculum graft was sutured in the capsule/sagittal band defect. The mean age of the patients was 22 years. In all patients, surgery was performed on the middle finger. The capsule was damaged on the ulnar side in 3 patients and on the radial side in 2 patients. RESULTS: All boxers reported alleviation of pain when punching. The range of motion for the MCP joint was not restricted after surgery in any patient. Tendon dislocation did not occur after surgery in any patient. All 5 patients were able to return to professional competition. CONCLUSIONS: Extensor retinaculum grafting is useful in treating chronic boxer's knuckle if the damaged capsule cannot be repaired directly. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Gene expression changes in an early stage of intervertebral disc degeneration induced by passive cigarette smoking.

STUDY DESIGN: This study attempts to determine the molecular changes in intervertebral disc degeneration of rats induced by passive cigarette smoking. OBJECTIVES: To quantitate and compare the gene expression levels in intervertebral discs from passively cigarette smoking rats and nonsmoking rats. SUMMARY OF BACKGROUND DATA: The molecular mechanism of intervertebral disc degeneration has been investigated mainly in vitro but little in vivo, and gene expression analysis has been performed in a few studies. The cigarette smoking is a risk factor of low back pain. We developed a smoking box to create a rat model of intervertebral disc degeneration induced by passive cigarette smoking. METHODS: Total RNA was extracted from intervertebral discs of rats that were raised in a cigarette-smoking box for 2 to 7 weeks. After synthesis of cDNA, the quantitative analysis of gene expression was performed by the real-time PCR. The remaining spines were subjected to the histologic examination. RESULTS: Histologic changes of the nucleus pulposus and the anulus fibrosus were detected after 2 weeks of smoking and were frequently found after 7 weeks. Collagen genes were downregulated remarkably after 7 weeks of smoking. No significant increase was observed in the expressions of matrix metalloproteinase-3, but the expression of tissue inhibitor of metalloproteinases-1 started to increase at 4 weeks of smoking. Aggrecan also started to be up-regulated at 4 weeks. CONCLUSIONS: Changes in gene expression by passive cigarette smoking precede the histologic changes in the intervertebral discs. Reactions to suppress the destruction of tissue matrix and to regenerate the intervertebral discs are occurring at the same time as the degenerative histologic changes.

Histological changes in intervertebral discs after smoking and cessation: experimental study using a rat passive smoking model.

BACKGROUND: Passive smoking has been reported to induce intervertebral disc degeneration in rats, and the objective of the present study was to histologically investigate changes in smoking-induced intervertebral disc degeneration after cessation of smoking. METHODS: Four-week-old rats were subjected to passive smoking for 8 weeks in a smoking box [20 cigarettes a day: one cigarette an hour (inhaled over 3 minutes and followed by ventilation with room air for 5 minutes)] to induce intervertebral disc degeneration. Smoke-free periods of different lengths were then established, and intervertebral discs were histologically analyzed. RESULTS: Immediately after 8 weeks of passive smoking, intervertebral discs exhibited cracks, tears, and misalignment of the annulus fibrosus, and increased fibrous tissue was seen in the nucleus pulposus. In addition, the level of interleukin-1beta in intervertebral discs was higher in the smoking group than in the non-smoking group. After cessation, progression of degeneration ceased, and the matrix of the nucleus pulposus and annulus fibrosus exhibited increased fibrous connective tissue and proteoglycan. However, there were no changes in annulus fibrosus misalignment. Interleukin-1beta levels also remained significantly elevated after 8 weeks of cessation. CONCLUSIONS: While the annulus fibrosus degeneration caused by smoking was partially irreversible after cessation of smoking, the amount of mucin (proteoglycan) in the nucleus pulposus and annulus fibrosus tended to increase after cessation, thus suggesting the possibility that smoking-induced intervertebral disc degeneration can be repaired to some degree by cessation of smoking.

Effectiveness of posterior decompression for patients with ossification of the posterior longitudinal ligament in the thoracic spine: usefulness of the ossification-kyphosis angle on MRI.

STUDY DESIGN: A reliability study was conducted. OBJECTIVE: To report the utility of the ossification- kyphosis angle of a decompression site in the sagittal view of MRI in the preoperative evaluation of the effectiveness of posterior decompression for patients with ossification of the posterior longitudinal ligament in the thoracic spine. SUMMARY OF BACKGROUND DATA: In patients with ossification of the posterior longitudinal ligament, in the thoracic spine, posterior decompression may not always be effective for those with physiologic kyphosis; however, posterior decompression is sometimes useful for patients with multilevel lesions or with ossification of the ligamentum flavum. Therefore, it is necessary to evaluate the indications or limitations of posterior decompression before surgery. METHODS: The indications or limitations of posterior decompression for this disease were reviewed from the findings of intraoperative ultrasonography and various parameters on preoperative imaging in 22 patients with thoracic myelopathy. RESULTS: Thirteen patients had echo-free space and 9 patients had no echo-free space in intraoperative ultrasonography after posterior decompression. In the kyphosis angle of the decompression site and the configuration of the maximal prominent OPLL, there was no significant difference between the group with echo-free space and the group without echo-free space (P = 0.49, P = 0.55). On the other hand, the ossification-kyphosis angle of the decompression site was more than 23 degrees in all patients with no echo-free space (23 degrees -34 degrees , 28.2 degrees +/- 3.6 degrees ), and it was less than 23 degrees in all patients with echo-free space (10 degrees -23 degrees , 17.4 degrees +/- 4.1 degrees ). There was also significant difference between the groups statistically (P < 0.01, P = 1.50789E-06). In addition, in the occupation rate of the greatest prominence of the OPLL, there was statistically significant difference between the groups (P = 0.032). CONCLUSION: The ossification-kyphosis angle in the sagittal view of MRI has potential as an indicator of the effectiveness of posterior decompression in this disease. It is thought that there is a critical point of posterior decompression at nearly 23 degrees of the ossification-kyphosis angle of the decompression site. When the ossification-kyphosis angle is more than 20 degrees , the presence of echo free space should be carefully confirmed in intraoperative ultrasonography.

A revised scoring system for preoperative evaluation of metastatic spine tumor prognosis.

STUDY DESIGN: A semi-prospective clinical study was conducted. OBJECTIVES: To evaluate the accuracy of a revised scoring system predicting metastatic spinal tumor prognosis and the suitability of the subsequent treatment strategy. SUMMARY OF THE BACKGROUND DATA: We used a scoring system for the preoperative evaluation of the prognosis of metastatic spinal tumors and selected treatment methods for the predicted prognosis. In the previous version of our scoring system, the reliability of the predicting prognosis was 63.3% in 128 patients with metastatic spinal tumors. METHODS: The study participants were 164 patients who died after surgery and 82 who died after conservative treatment. Six parameters were used in the revised scoring system. Each parameter ranged from 0 to 5 points, and the total score was 15 points. In principle, conservative treatment or palliative procedures were indicated in patients with a total score of 8 or less (predicted survival period, less than 6 months) or those with multiple vertebral metastases, while excisional procedures were performed in patients with a total score of 12 or more (predicted survival period, 1 year or more) or those with a total score of 9 to 11 (predicted survival period, 6 months or more) and with metastasis in a single vertebra. The selection of treatment modality was followed faithfully according to the criteria of the revised scoring system after 1998. The prognosis predicted by the revised scoring system and the actual survival period after treatment were compared, and the reliability of the prognostic criteria was analyzed for the group subjected to it prospectively after 1998 (n = 118) and for all 246 patients it was applied to retrospectively. RESULTS: The total score for each patient could be correlated with the survival period. This correlation was also observed in each treatment group. The consistency rate between the predicted prognosis from the criteria of the total scores and the actual survival period was high in patients within each score range (0-8, 9-11, or 12-15), 86.4% in the 118 patients evaluated prospectively after 1998, and 82.5% in the 246 patients evaluated retrospectively. Furthermore, a similar result was also observed in both the surgical procedure group and conservative treatment group. The rate of consistency between the predicted prognosis and the actual survival period in each local extension of the lesion was 75% or more in all types, excluding Type 6 in the surgical classification of Tomita et al. CONCLUSION: The prognostic criteria using the total scores from our revised scoring system were useful for the pretreatment evaluation of metastatic spinal tumor prognosis irrespective of treatment modality or local extension of the lesion.

Trapeziometacarpal joint instability after Bennett's fracture-dislocation.

BACKGROUND: Investigation of trapeziometacarpal joint instability was undertaken following Bennett's fracture-dislocation. METHODS: We treated six patients who were experiencing trapeziometacarpal joint instability following Bennett's fracture-dislocation. The average age of the patients at the initial visit was 22.2 years. There were four men and two women. All six patients complained of trapeziometacarpal joint pain and instability preoperatively. Fluoroscopy confirmed that the beak fragment moved with the shaft fragment. The length of time from injury to surgery ranged from 1 to 29 months (average 10.7 months). Ligament reconstruction based on Eaton's method was performed on five patients, and in one patient the fracture site was osteotomized and reduced and the dorsoradial ligament repaired. RESULTS: Over an average follow-up observation period of 20 months, none of the patients complained of severe joint pain or instability. CONCLUSIONS: When treating Bennett's fracture-dislocation, it is necessary to pay careful attention not only to accurate anatomic reduction of the joint surface but also to joint instability.

Ultrasonography in tarsal tunnel syndrome.

OBJECTIVE: The purpose of this study was to clarify the diagnostic value of ultrasonography in tarsal tunnel syndrome. METHODS: Seventeen patients (17 feet) with tarsal tunnel syndrome were treated between 1988 and 2003. Preoperative ultrasonography was performed, and the cause of the syndrome was confirmed intraoperatively in all cases. Long and short axes of the tarsal tunnel were scanned to ascertain the presence of any space-occupying lesion. RESULTS: The causes of tarsal tunnel syndrome, as confirmed by surgery, were ganglia (n = 10), talocalcaneal coalition (n = 1), talocalcaneal coalition associated with ganglia (n = 3), and varicose veins (n = 3). Among the cases involving ganglia, hypoechoic or anechoic regions were observed. The mean sizes +/- SD of these regions were 19.4 +/- 8.8 mm in the long axis, 15.2 +/- 6.3 mm in the short axis, and 10.4 +/- 3.8 mm in depth. Of these, 3 ganglia were not clearly palpable before surgery and were small: 10 x 10 x 7, 13 x 11 x 9, and 9 x 8 x 7 mm. Among the cases involving talocalcaneal coalition, ultrasonography indicated a beak-shaped bony process on the short axis images. Although these 3 cases were associated with ganglia, this could not be determined by preoperative palpation. CONCLUSIONS: As a diagnostic imaging technique for tarsal tunnel syndrome, ultrasonography is extremely useful for identifying space-occupying lesions. Ultrasonography should be performed routinely in patients with suspected tarsal tunnel syndrome.