Mechanical prophylaxis is a heparin-independent risk for anti-platelet factor 4/heparin antibody formation after orthopedic surgery.

Platelet-activating antibodies, which recognize platelet factor 4 (PF4)/heparin complexes, induce spontaneous heparin-induced thrombocytopenia (HIT) syndrome or fondaparinux-associated HIT without exposure to unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). This condition mostly occurs after major orthopedic surgery, implying that surgery itself could trigger this immune response, although the mechanism is unclear. To investigate how surgery may do so, we performed a multicenter, prospective study of 2069 patients who underwent total knee arthroplasty (TKA) or hip arthroplasty. Approximately half of the patients received postoperative thromboprophylaxis with UFH, LMWH, or fondaparinux. The other half received only mechanical thromboprophylaxis, including dynamic (intermittent plantar or pneumatic compression device), static (graduated compression stockings [GCSs]), or both. We measured anti-PF4/heparin immunoglobulins G, A, and M before and 10 days after surgery using an immunoassay. Multivariate analysis revealed that dynamic mechanical thromboprophylaxis (DMT) was an independent risk factor for seroconversion (odds ratio [OR], 2.01; 95% confidence interval [CI], 1.34-3.02; P = .001), which was confirmed with propensity-score matching (OR, 1.99; 95% CI, 1.17-3.37; P = .018). For TKA, the seroconversion rates in patients treated with DMT but no anticoagulation and in patients treated with UFH or LMWH without DMT were similar, but significantly higher than in patients treated with only GCSs. The proportion of patients with ≥1.4 optical density units appeared to be higher among those treated with any anticoagulant plus DMT than among those not treated with DMT. Our study suggests that DMT increases risk of an anti-PF4/heparin immune response, even without heparin exposure. This trial was registered to www.umin.ac.jp/ctr as #UMIN000001366.

A genome-wide sib-pair linkage analysis of ossification of the posterior longitudinal ligament of the spine.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is a common musculoskeletal disease among people after middle age. The OPLL presents with serious neurological abnormalities due to compression of the spinal cord and nerve roots. The OPLL is caused by genetic and environment factors; however, its etiology and pathogenesis still remain to be elucidated. To determine the susceptibility loci for OPLL, we performed a genome-wide linkage study using 214 affected sib-pairs of Japanese. In stratification analyses for definite cervical OPLL, we found loci with suggestive linkage on 1p21, 2p22-2p24, 7q22, 16q24 and 20p12. Fine mapping using additional markers detected the highest non-parametric linkage score (3.43, P = 0.00027) at D20S894 on chromosome 20p12 in a subgroup that had no complication of diabetes mellitus. Our result would shed a new light on genetic aspects of OPLL.

Statistical analysis of prognostic factors for survival in patients with spinal metastasis.

There are a variety of treatment options for patients with spinal metastasis, and predicting prognosis is essential for selecting the proper treatment. The purpose of the present study was to identify the significant prognostic factors for the survival of patients with spinal metastasis. We retrospectively reviewed 143 patients with spinal metastasis. The median age was 61 years. Eleven factors reported previously were analyzed using the Cox proportional hazards model:gender, age, performance status, neurological deficits, pain, type of primary tumor, metastasis to major organs, previous chemotherapy, disease-free interval before spinal metastasis, multiple spinal metastases, and extra-spinal bone metastasis. The average survival of study patients after the first visit to our clinic was 22 months. Multivariate survival analysis demonstrated that type of primary tumor (hazard ratio [HR] = 6.80, p < 0.001), metastasis to major organs (HR = 2.01, p = 0.005), disease-free interval before spinal metastasis (HR = 1.77, p = 0.028), and extra-spinal bone metastasis (HR = 1.75, p = 0.017) were significant prognostic factors. Type of primary tumor was the most powerful prognostic factor. Other prognostic factors may differ among the types of primary tumor and may also be closely associated with primary disease activity. Further analysis of factors predicting prognosis should be conducted with respect to each type of primary tumor to help accurately predict prognosis.

Perioperative complications of anterior cervical decompression with fusion in patients with ossification of the posterior longitudinal ligament: a retrospective, multi-institutional study.

BACKGROUND: Anterior decompression with fusion (ADF) for patients with cervical ossification of the posterior longitudinal ligament (OPLL) is reportedly associated with a higher incidence of complications than is laminoplasty. However, the frequency of perioperative complications associated with ADF for cervical OPLL has not been fully established. The purpose of this study was to investigate the incidence of perioperative complications, especially neurological complications, following ADF performed to relieve compressive cervical myelopathy due to cervical OPLL. METHODS: Study participants comprised 150 patients who had undergone ADF for cervical OPLL at 27 institutions between 2005 and 2008. Perioperative--especially neurological--complications occurring within 2 weeks after ADF were analyzed. Preoperative imaging findings, including Cobb angle, between C2 and C7 and occupying ratio of OPLL were investigated. Multivariate analysis with logistic regression was performed to identify independent risk factors for neurological complications. RESULT: Three patients (2.0 %) showed deterioration of lower-extremity function after ADF. One of the three patients had not regained their preoperative level of function 6 months after surgery. Upper-extremity paresis occurred in 20 patients (13.3 %), five of whom had not returned to preoperative levels 6 months after surgery. Patients with upper-extremity paresis showed significantly higher occupying ratios of OPLL, greater blood loss, longer operation times, fusion of more segments, and higher rates of cerebrospinal fluid leakage than those without paresis. Independent risk factors for upper-extremity paresis were a high occupying ratio of OPLL and large blood loss during surgery. CONCLUSIONS: The incidences of deterioration in upper- and lower-extremity functions were 13.3 % and 2.0 %, respectively. Patients with a high occupying ratio of OPLL are at higher risk of developing neurological deterioration.

Charlson comorbidity index is predictive of postoperative clinical outcome after single-level posterior lumbar interbody fusion surgery.

BACKGROUND: In several previous studies, Charlson comorbidity index (CCI) score was associated with postoperative complications, mortality, and re-admission. There are few reports about the influence of CCI score on postoperative clinical outcome. The purpose of this study was to investigate the influence of comorbidities as calculated with CCI on postoperative clinical outcomes after PLIF. METHODS: Three hundred sixty-six patients who underwent an elective primary single-level PLIF were included. Postoperative clinical outcome was evaluated with the Japanese Orthopaedic Association lumbar score (JOA score). The correlation coefficient between the CCI score and postoperative improvement in JOA score was investigated. Patients were divided into three groups according to their CCI score (0, 1, and 2+). JOA improvement rate, length of stay (LOS), and direct cost were compared between each group. Postoperative complications were also investigated. RESULTS: There was a weak negative relationship between CCI score and JOA improvement rate (r = - 0.20). LOS and direct cost had almost no correlation with CCI score. The JOA improvement rate of group 0 and group 1 was significantly higher than group 2+. LOS and direct cost were also significantly different between group 0 and group 2+. There were 14 postoperative complications. Adverse postoperative complications were equivalently distributed in each group, and not associated with the number of comorbidities. CONCLUSIONS: A higher CCI score leads to a poor postoperative outcome. The recovery rate of patients with two or more comorbidities was significantly higher than in patients without comorbidities. However, the CCI score did not influence LOS and increased direct costs. The surgeon must take into consideration the patient's comorbidities when planning a surgical intervention in order to achieve a good clinical outcome.

Surgical treatment of metastatic vertebral tumors.

Surgical treatment of metastatic spinal cord compression is controversial. The purpose of this study was to investigate the effectiveness of our current surgical treatments and the use of spinal instrumentation. In this retrospective study covering the years between 1990 and 2006, 100 patients with spinal metastases which were secondary to various cancers underwent posterior and/or anterior decompression with spinal stabilization for the purposes of reduction of pain, and/or to help correct or improve neurological deficits. The group was made up of 60 men and 40 women whose ages ranged from 16 to 83 years (average of 60 years), and the average follow-up period was 14 months. The effect of treatment upon pain relief and neural deficits was assessed, and the cumulative survival rate was calculated by the Kaplan-Meier method. The average surgical time was 185 min. This was calculated based on the following times, listed here with the surgery type: 178 min for posterior surgery; 245 min for anterior surgery;465 min for combined surgery;and 475 min for total en bloc spondylectomy. Average blood loss during surgery was 1,630 ml for posterior surgery, 1,760 ml for anterior surgery, 1,930 ml for combined surgery, and 3,640 ml for total en bloc spondylectomy. Preoperative pain and paralysis were improved by 88% and 53%, respectively. In regards to surgical complications, postoperative epidural hematoma was observed in 2 patients, and instrumentation-related infection was observed in 1. Only 2 patients died within 2 months of surgery. In conclusion, posterior and/or anterior decompression with spinal stabilization is a safe and effective treatment for patients with spinal metastases, and can improve their quality of life.

SAPHO syndrome with rapidly progressing destructive spondylitis: two cases treated surgically.

The authors present two cases of synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome with rapidly progressing destructive spondylitis treated surgically. The spinal lesions in SAPHO syndrome generally have a good prognosis and rarely cause the structural destruction or neurological deterioration. Case 1: a 63-year-old female had palmoplantar pustulosis for 2 years. At first, she only felt a pain in the nape with no inducing factor. Two months later, she had incomplete quadriplegia (ASIA scale C). Magnetic resonance imaging showed destruction of C4-C7, kyphotic deformity, and severe compression of the spinal cord. Decompression and reconstruction surgery using anterior and posterior approach improved her paralysis. Case 2: a 69-year-old female complained of persistent back pain. Magnetic resonance imaging revealed spondylitis of T7-T9. Although there were no typical skin lesions, we diagnosed SAPHO syndrome by hyperostosis of the sternocostoclavicular joint and sacral joint. Destruction with kyphotic deformity of the spine progressed gradually for 3 months. Curettage and reconstruction surgery using thoracic endoscope relieved her pain and prevented the destruction of the spine. The histopathology of the specimen obtained surgically showed non-specific inflammation in both cases. Spondylitis in SAPHO syndrome may cause severe destruction and kyphotic deformity followed by paralysis.

SAPHO syndrome associated spondylitis.

The concept of synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome has been well clarified, after Chamot et al. suggested this peculiar disorder in 1987. The most commonly affected site in SAPHO syndrome is the anterior chest, followed by the spine. However, the clinical course and taxonomic concept of SAPHO spinal lesions are poorly understood. This study was performed to analyze: (1) the detailed clinical course of spinal lesions in SAPHO syndrome, and (2) the relationship between SAPHO syndrome with spinal lesions and seronegative spondyloarthropathy. Thirteen patients with spondylitis in SAPHO syndrome were analyzed. The features of spinal lesions were a chronic onset with a slight inflammatory reaction, and slowly progressing non-marginal syndesmophytes at multi spinal levels, besides the coexistence of specific skin lesions. SAPHO syndrome, especially spinal lesions related to palmoplantar pustulosis, can be recognized as a subtype of seronegative spondyloarthropathy.

Visualization of cerebrospinal fluid flow in syringomyelia through noninvasive magnetic resonance imaging with a time-spatial labeling inversion pulse (Time-SLIP).

CONTEXT: We report a case of syringomyelia assessed by magnetic resonance imaging (MRI) with a time-spatial labeling inversion pulse (Time-SLIP), which is a non-contrast MRI technique that uses the cerebrospinal fluid (CSF) as an intrinsic tracer, thus removing the need to administer a contrast agent. Time-SLIP permits investigation of flow movement for over 3 seconds without any limitations associated with the cardiac phase, and it is a clinically accessible method for flow analysis. FINDINGS: We investigated an 85-year-old male experiencing progressive gait disturbance, with leg numbness and muscle weakness. Conventional MRI revealed syringomyelia from C7 to T12, with multiple webs of cavities. We then applied the Time-SLIP approach to characterize CSF flow in the syringomyelic cavities. Time-SLIP detected several unique CSF flow patterns that could not be observed by conventional imaging. The basic CSF flow pattern in the subarachnoid space was pulsatile and was harmonious with the heartbeat. Several unique flow patterns, such as bubbles, jumping, and fast flow, were observed within syringomyelic cavities by Time-SLIP imaging. These patterns likely reflect the complex flow paths through the septum and/or webs of cavities. CONCLUSION/CLINICAL RELEVANCE: Time-SLIP permits observation of CSF motion over a long period of time and detects patterns of flow velocity and direction. Thus, this novel approach to CSF flow analysis can be used to gain a more extensive understanding of spinal disease pathology and to optimize surgical access in the treatment of spinal lesions. Additionally, Time-SLIP has broad applicability in the field of spinal research.

Surgical results of sacral perineural (Tarlov) cysts.

The purpose of this study was to investigate the surgical outcomes and to determine indicators of the necessity of surgical intervention. Twelve consecutive patients harboring symptomatic sacral perineural cysts were treated between 1995 and 2003. All patients were assessed for neurological deficits and pain by neurological examination. Magnetic resonance of imaging, computerized tomography, and myelography were performed to detect signs of delayed filling of the cysts. We performed a release of the valve and imbrication of the sacral cysts with laminectomies in 8 cases or recapping laminectomies in 4 cases. After surgery, symptoms improved in 10 (83%) of 12 patients, with an average follow-up of 27 months. Ten patients had sacral perineural cysts with signs of positive filling defect. Two (17%) of 12 patients experienced no significant improvement. In one of these patients, the filling defect was negative. In conclusion, a positive filling defect may become an indicator of good treatment outcomes.

Pathogenesis and diagnosis of delayed vertebral collapse resulting from osteoporotic spinal fracture.

BACKGROUND CONTEXT: In recent years there have been an increasing number of reports on surgical cases involving delayed neurological deficits caused by vertebral collapse after osteoporotic vertebral fracture. PURPOSE: We do not yet know which patients are most susceptible to delayed vertebral collapse and subsequent neurological deficits, or whether this pathological condition can be prevented or predicted. In this study, we investigated the mechanism of progression and radiographic features characteristic of this disease, and we report here the predictive or risk factors for delayed osteoporotic vertebral collapse. STUDY DESIGN: Retrospectively, we investigated the pathogenesis and diagnosis of delayed vertebral collapse with neurological deficit resulting from osteoporosis. PATIENT SAMPLE: A total of 28 patients (7 men and 21 women) with neurological deficits resulting from vertebral collapse caused by osteoporotic vertebral fractures were the subjects for this study. OUTCOME MEASURES: Comparisons and investigations about clinical features and radiographic findings between the patient group of delayed vertebral collapse with neurological deficits and the group of osteoporotic spinal fracture with no neurological deficits. METHODS: The following factors were examined: the cause of injury; the length of time from injury, or the onset of pain, to the onset of neurological symptoms; radiographic findings obtained during the above period; the clinical course of vertebral fracture on plain X-ray films; time of appearance of the intravertebral cleft, and its localization and changes. RESULTS: Six patients were hospitalized and prescribed a period of 2 weeks of bed rest followed by the fitting of a corset; seven outpatients were corseted but not prescribed bed rest; 15 patients were given medication only at an outpatient clinic. At radiography, intravertebral clefts were detected in 22 patients (79%) during the period from the appearance of pain to the onset of neurological deficit. In 14 patients (50%) who were radiographed every 1 to 2 weeks from the injury to the onset of neurological symptoms, the course of progression to collapse of the vertebral body could be observed. CONCLUSION: Initial correct diagnosis and immobilization are important in preventing the delayed collapse with neurological deficit. The presence of an intravertebral cleft and instability of the affected vertebra represent risk factors for vertebral collapse with neurological deficit, requiring careful observation.

Acute cervical spinal cord injury complicated by preexisting ossification of the posterior longitudinal ligament: a multicenter study.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVE: To review the clinical characteristics of traumatic cervical spinal cord injury (SCI) associated with ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: Despite its potentially devastating consequences, there is a lack of information about acute cervical SCI complicated by OPLL. METHODS: This study included consecutive patients with acute traumatic cervical SCI (Frankel A, B, and C) who were admitted within 48 hours of injury to 34 spine institutions across Japan. For analysis of neurologic outcome, patients who had completed at least a 6-month follow-up were included. Neurologic improvement was defined as at least one grade conversion in Frankel grade. RESULTS: A total of 453 patients were identified (367 men, 86 women; mean age, 59 years). OPLL was found in 106 (23%) patients (87 men, 19 women; mean age, 66 years). Most of the patients with OPLL (94 of 106) were without bone injury, presenting with incomplete SCI. The prevalence of OPLL reached 34% in SCI without bone injury. The cause of SCI was predominantly falls (74%). Only 25% of the patients were aware of OPLL. Half of the OPLL patients reported gait disturbance before injury. Forty-eight (52%) OPLL patients without bone injury underwent surgery (median, 13.5 days after injury), mostly laminoplasty. Overall, no significant difference was noted in neurologic improvement between surgery group and conservative group. However, further stratification showed that surgery was associated with greater neurologic recovery in patients who had gait disturbance before injury (P = 0.04). CONCLUSION: Prevalence of OPLL among cervical SCI was alarmingly high, especially in those without bone injury. Most of cervical SCI associated with OPLL were incomplete, without bone injury, and caused predominantly by low-energy trauma. The majority of the patients were unaware of OPLL. Surgery produced better neurologic recovery in patients who had gait disturbance before injury.

Neurological complications of cervical laminoplasty for patients with ossification of the posterior longitudinal ligament-a multi-institutional retrospective study.

STUDY DESIGN: Retrospective multi-institutional study. OBJECTIVE: To investigate the incidence of neurological deficits after cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND DATA: According to analysis of long-term results, laminoplasty for cervical OPLL has been reported as a safe and effective alternative procedure with few complications. However, perioperative neurological complication rates of laminoplasty for cervical OPLL have not been well described. METHODS: Subjects comprised 581 patients (458 men and 123 women; mean age: 62 ± 10 years; range: 30-86 years) who had undergone laminoplasty for cervical OPLL at 27 institutions between 2005 and 2008. Continuous-type OPLL was seen in 114, segmental-type in 146, mixed-type in 265, local-type in 24, and not judged in 32 patients. Postoperative neurological complications within 2 weeks after laminoplasty were analyzed in detail. Cobb angle between C2 and C7 (C2/C7 angle), maximal thickness, and occupying rate of OPLL were investigated. Pre- and postoperative magnetic resonance imaging was performed on patients with postoperative neurological complications. RESULTS: Open-door laminoplasty was conducted in 237, double-door laminoplasty in 311, and other types of laminoplasty in 33 patients. Deterioration of lower-extremity function occurred after laminoplasty in 18 patients (3.1%). Causes of deterioration were epidural hematoma in 3, spinal cord herniation through injured dura mater in 1, incomplete laminoplasty due to vertebral artery injury while making a trough in 1, and unidentified in 13 patients. Prevalence of unsatisfactory recovery not reaching preoperative level by 6-month follow-up was 7/581 (1.2%). Mean occupying rate of OPLL for patients with deteriorated lower-extremity function was 51.2 ± 13.6% (range, 21.0%-73.3%), significantly higher than the 42.3 ± 13.0% for patients without deterioration. OPLL thickness was also higher in patients with deterioration (mean, 6.6 ± 2.2 mm) than in those without deterioration (mean, 5.7 ± 2.0 mm). No significant difference in C2/C7 lordotic angle was seen between groups. CONCLUSION: Although most neurological deterioration can be expected to recover to some extent, the frequency of short-term neurological complications was higher than the authors expected.

Diagnostic validity of space available for the spinal cord at C1 level for cervical myelopathy in patients with rheumatoid arthritis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To evaluate diagnostic validity of space available for the spinal cord (SAC) at C1 level for myelopathy in patients with rheumatoid arthritis (RA). SUMMARY OF BACKGROUND DATA: The relationship of SAC at C1 level with myelopathy has been evaluated by relatively small number of the patients, and 2 criteria have been proposed. METHODS: Two cohorts of the patients with RA were established. Group A consisted of 140 patients with myeopathy due to upper cervical involvement selected from the database. Group B consisted of 99 patients with upper cervical subluxation, but not associated with myelopathy selected from the consecutive series of the hospitalized patients. Distributions of SAC at C1 level in both groups were evaluated. Efficacy indexes for screening (sensitivity, specificity, etc.) were calculated for these patients' population by previously demonstrated 2 criteria. In addition, analysis according to receiver operating characteristic (ROC) curve was performed. RESULTS: The average values of SAC were 11.1 mm in Group A and 16.5 mm in Group B. When cut-off point for myelopathy was defined as 13 mm or less, sensitivity and specificity were 82% and 85%, respectively. When it was defined as 14 mm or less, sensitivity increased (88%) while specificity decreased (74%). Accuracies by these 2 criteria were almost the same (83%, 82%). The left upper corner point of ROC curve was located between these 2 cut-off points. CONCLUSION: Distributions of SAC showed that SAC was a reliable parameter for relating myelopathy in patients with upper cervical subluxation in RA. The plots according to ROC curve showed adequacy of previously demonstrated 2 cut-off points. For the purpose to screen the patients with high risk for myelopathy, 14 mm or less was recommended as a cut-off point of SAC.

Surgical results and related factors for ossification of posterior longitudinal ligament of the thoracic spine: a multi-institutional retrospective study.

STUDY DESIGN: Retrospective multi-institutional study OBJECTIVE: To describe the surgical outcomes in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to clarify factors related to the surgical outcomes. SUMMARY OF BACKGROUND DATA: Detailed analyses of surgical outcomes of T-OPLL have been difficult because of the rarity of this disease. METHODS: The subjects were 154 patients with T-OPLL who were surgically treated at 34 institutions between 1998 and 2002. The surgical procedures were laminectomy in 36, laminoplasty in 51, anterior decompression via anterior approach in 25 and via posterior approach in 29, combined anterior and posterior fusion in 8, and sternum splitting approach in 5 patients. Instrumentation was conducted in 52 patients. Assessments were made on (1) The Japanese Orthopedic Association (JOA) scores (full score, 11 points), its recovery rates, (2) factors related to surgical results, and (3) complications and their consequences. RESULTS: (1) The mean JOA score before surgery was 4.6 +/- 2.0 and, 7.1 +/- 2.5 after surgery. The mean recovery rate was 36.8% +/- 47.4%. (2) The recovery rate was 50% or higher in 72 patients (46.8%). Factors significantly related to this were location of the maximum ossification (T1-T4) (odds ratio, 2.43-4.17) and the use of instrumentation (odds ratio, 3.37). (3) The frequent complications were deterioration of myelopathy immediately after surgery in 18 (11.7%) and dural injury in 34 (22.1%) patients. CONCLUSION: The factors significantly associated with favorable surgical results were maximum ossification located at the upper thoracic spine and use of instrumentation. T-OPLL at the nonkyphotic upper thoracic spine can be treated by laminoplasty that is relatively a safe surgical procedure for neural elements. The use of instrumentation allows correction of kyphosis or prevention of progression of kyphosis, thereby, enhancing and maintaining decompression effect, and its use should be considered with posterior decompression.

Nationwide survey on complications of spine surgery in Japan.

The Japan Spine Research Society carried out a nationwide survey on complications of the spine, enrolling a total of 16 157 patients who had undergone spine surgery in 196 institutes in the 1-year period from January to December 2001. Diseases, surgical procedures, and complications were surveyed in detail. Forty-nine percent of patients were aged 60 years or older, which was remarkably increased in comparison with the percentage reported by the 1994 survey (37.3%). The number of cases with degenerative spinal diseases comprised 78.2% of the total number of spine surgery cases. The percentage of patients with stenosis was the greatest (38.5%), reflecting the increase in the elderly population undergoing spine surgery. Spinal instrumentation was used with 5497 patients (34.0%). The frequency of its use was much greater than that reported in 1994 (27.0%). The pedicle screw was the most frequently used instrument (54.6%). The use of spinal instrumentation greatly increased for spinal deformity, trauma, and tumors. Posterior lumbar interbody fusion has been increasingly used in cases of lumbar degenerative disease. Complications of spinal surgery were reported in 1383 patients (8.6%). The incidence of complications associated with instrumentation surgery was 12.1%, being twice as much as that associated with noninstrumentation surgery (6.8%).