Finite Element Analysis of the Mechanical Strength of Phalangeal Osteosynthesis Using Kirschner Wires.

Background: Kirschner wire (K-wire) fixation is widely used to repair metacarpal and phalangeal fractures. In this study, we simulated K-wire osteosynthesis of a 3-dimensional (3D) phalangeal fracture model and investigated the fixation strength at various K-wire diameters and insertion angles to clarify the optimal K-wire fixation method for phalangeal fractures. Methods: The 3D phalangeal fracture models were created by using computed tomographic (CT) images of the proximal phalanx of the middle finger in five young healthy volunteers and five elderly osteoporotic patients. Two elongated cylinders representing K-wires were inserted according to various cross-pinning methods; the wire diameters were 1.0, 1.2, 1.5 and 1.8 mm, and the wire insertion angles (i.e. the angle between the fracture line and the K-wire) were 30°, 45° and 60°. The mechanical strength of the K-wire fixed fracture model was investigated by using finite element analysis (FEA). Results: The fixation strength increased with increasing wire diameter and insertion angle. Insertion of 1.8-mm wires at 60° achieved the strongest fixation force in this series. Fixation strength was generally stronger in the younger group than the elderly group. Dispersion of stress to cortical bone was a critical factor to increase fixation strength. Conclusions: We developed a 3D phalangeal fracture model into which we inserted K-wires; using FEA, we clarified the optimal crossed K-wire fixation method for phalangeal fractures. Level of Evidence: Level V (Therapeutic).

The impact of diabetes mellitus on spinal fracture with diffuse idiopathic skeletal hyperostosis: A multicenter retrospective study.

BACKGROUND: Patients with diffuse idiopathic skeletal hyperostosis (DISH) are susceptible to spinal column injuries with neurological deterioration. Previous studies indicated that the prevalence of diabetes mellitus (DM) in patients with DISH was higher than that in patients without DISH. This study investigates the impact of DM on surgical outcomes for spinal fractures in patients with DISH. METHODS: We retrospectively evaluated 177 spinal fractures in patients with DISH (132 men and 45 women; mean age, 75 ± 10 years) who underwent surgery from a multicenter database. The subjects were classified into two groups according to the presence of DM. Perioperative complications, neurological status by Frankel grade, mortality rate, and status of surgical site infection (SSI) were compared between the two groups. RESULTS: DM was present in 28.2% (50/177) of the patients. The proportion of men was significantly higher in the DM group (DM group: 86.0% vs. non-DM group: 70.1%) (p = 0.03). The overall complication rate was 22.0% in the DM group and 19.7% in the non-DM group (p = 0.60). Poisson regression model revealed that SSI was significantly associated with DM (DM group: 10.0% vs. non-DM group: 2.4%, Relative risk: 4.5) (p = 0.048). Change in neurological status, mortality rate, instrumentation failure, and nonunion were similar between both groups. HbA1c and fasting blood glucose level (SSI group: 7.2% ± 1.2%, 201 ± 67 mg/dL vs. non-SSI group: 6.6% ± 1.1%, 167 ± 47 mg/dL) tended to be higher in patients with SSI; however, there was no significant difference. CONCLUSIONS: In spinal fracture in patients with DISH, although DM was an associated factor for SSI with a relative risk of 4.5, DM did not negatively impact neurological recovery. Perioperative glycemic control may be useful for preventing SSI because fasting blood glucose level was high in patients with SSI.

Cytological detection of metastatic chordoma cells in pleural effusions: A case report.

Cytological detection of chordoma cells in the serosal cavity is challenging because of its rare presentation. Herein, we report a case of chordoma showing malignant pleural effusion accompanied by pleuropulmonary metastases in a 68-year-old woman. Cytological analysis was performed using pleural fluid obtained following thoracentesis. Conventional cytological staining demonstrated few clusters of large, atypical cells characterized by epithelial cell-like connectivity and rich cytoplasm with foamy and/or multivacuolar changes. The nuclei of these atypical cells were large and either round or oval with no conspicuous irregularities in the nuclear membrane. Periodic acid-Schiff staining of these atypical cells revealed fine granules in the cytoplasm. Giemsa staining showed foamy and/or multivacuolar cytoplasm in these cells, with metachromatic mucoid stroma in the surroundings. Immunocytochemistry analysis using cellblock showed these cells to be positive for broad cytokeratins, epithelial membrane antigen, S100 protein, vimentin, and Brachyury. To the best of our knowledge, this is the first case report in which chordoma cells were cytologically detected in pleural effusions. Our findings also suggest that conventional cytology combined with cellblock immunocytochemistry can increase the accuracy of chordoma cell detection in the serosal cavity.

Impact of K-Line (-) in the Neck-Flexion Position on Patient-reported Outcomes After Cervical Laminoplasty For Patients With Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: This study was a post hoc analysis of prospective data. OBJECTIVE: The objective of this study was to investigate whether K-line (-) in the neck-flexion position [f-K-line (-)] affects patient-reported outcome measures after cervical laminoplasty for patients with ossification of the posterior longitudinal ligament (OPLL). SUMMARY OF BACKGROUND AND DATA: The f-K-line was recently proposed as a predictor of poor outcomes after laminoplasty for patients with OPLL. However, its impact on patient-reported outcome measures remains to be elucidated. PATIENTS AND METHODS: We analyzed prospectively collected data from 68 patients with cervical myelopathy due to OPLL who underwent double-door laminoplasty between 2008 and 2015. Patients were categorized into f-K-line (-) and f-K-line (+) groups on a baseline neck-flexion radiograph. Outcome measures included the Japanese Orthopaedic Association score, EuroQol 5-Dimensional Questionnaire, the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire, and 11-point Numerical Rating Scale for pain. The degree of satisfaction with the outcome was assessed at the 2-year follow-up using a 7-point Numerical Rating Scale. RESULTS: Of the 68 patients, 22 (32%) and 46 (68%) were grouped into the f-K-line (-) and f-K-line (+) groups, respectively. The 2 groups showed no significant difference in baseline functions. The f-K-line (-) group showed a significantly lower recovery rate of the Japanese Orthopaedic Association score and a significantly lower gain in EuroQol 5-Dimensional Questionnaire score than compared with the f-K-line (+) group at the 2-year follow-up. Among the 5 domains of the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire, cervical function, and upper extremity function were significantly lower in the f-K-line (-) group than in the f-K-line (+) group. Patients in the f-K-line (-) group also reported a significantly higher pain intensity in the upper and lower extremities and a significantly lower degree of satisfaction compared with those in the f-K-line (+) group. CONCLUSION: The f-K-line (-) was significantly associated with poorer functional recovery, higher pain intensity in the extremities, and lower patient satisfaction after cervical laminoplasty for patients with OPLL.

Spinal fractures in patients with Diffuse idiopathic skeletal hyperostosis:A nationwide multi-institution survey.

BACKGROUND: Diffuse idiopathic skeletal hyperostosis (DISH) increases the spine's susceptibility to unstable fractures that can cause neurological deterioration. However, the detail of injury is still unclear. A nationwide multicenter retrospective study was conducted to assess the clinical characteristics and radiographic features of spinal fractures in patients with DISH. METHODS: Patients were eligible for this study if they 1) had DISH, defined as flowing ossification along the anterolateral aspect of at least four contiguous vertebral bodies, and 2) had an injury in the ankylosing spine. This study included 285 patients with DISH (221 males, 64 females; mean age 75.2 ± 9.5 years). RESULTS: The major cause of injury was falling from a standing or sitting position; this affected 146 patients (51.2%). Diagnosis of the fracture was delayed in 115 patients (40.4%). Later neurological deterioration by one or more Frankel grade was seen in 87 patients (30.5%). The following factors were significantly associated with neurological deficits: delayed diagnosis (p = 0.033), injury of the posterior column (p = 0.021), and the presence of ossification of the posterior longitudinal ligament (OPLL) (p < 0.001). The majority of patients (n = 241, 84.6%) were treated surgically, most commonly by conventional open posterior fixation (n = 199, 69.8%). Neurological improvement was seen in 20.0% of the conservatively treated patients, and in 47.0% of the patients treated surgically. CONCLUSIONS: Minor trauma could cause spinal fractures in DISH patients. Delayed diagnosis, injury of the posterior column, and the presence of OPLL were significantly associated with neurological deterioration. Patients with neurological deficits or unstable fractures should be treated by fixation surgery.

Predictors of Persistent Axial Neck Pain After Cervical Laminoplasty.

STUDY DESIGN: Retrospective analysis of prospective data. OBJECTIVE: The aim of this study was to reveal baseline predictors of persistent postlaminoplasty neck pain. SUMMARY OF BACKGROUND DATA: Axial neck pain is one of the most common complications after cervical laminoplasty; however, baseline predictors of persistent postlaminoplasty neck pain are unclear. METHODS: We analyzed data from 156 patients who completed a 2-year follow-up after double-door laminoplasty for degenerative cervical myelopathy. Patients rated the average intensity of axial neck pain in the last month using an 11-point numerical rating scale preoperatively and at the 2-year follow-up. The dependent variable was the presence of moderate-to-severe neck pain (numerical rating scale ≥4) at the 2-year follow-up. The independent variables included patient characteristics, baseline radiological parameters, surgical variables, baseline axial neck pain intensity, and baseline functions, which were measured by the Japanese Orthopaedic Association score and the Short Form-36 survey (SF-36). Logistic regression analysis was performed to identify independent predictors of moderate-to-severe neck pain after laminoplasty. RESULTS: At the 2-year follow-up, 51 patients (32%) had moderate-to-severe neck pain, and 106 patients (68%) had no or mild pain. Univariate analysis revealed that the ratio of cervical anterolisthesis, ratio of current smoking, baseline neck pain intensity, and baseline SF-36 Mental Component Summary differed significantly between the groups. Multivariate logistic regression analysis showed that independent predictors of moderate-to-severe neck pain at the 2-year follow-up include the presence of anterolisthesis, current smoking, moderate-to-severe baseline neck pain, and lower SF-36 Mental Component Summary. The presence of anterolisthesis and moderate-to-severe baseline neck pain were also associated with significantly poorer physical function after surgery. CONCLUSION: The presence of anterolisthesis was associated not only with the highest odds ratio of persistent neck pain but also with significantly poorer functional outcomes. Indications for cervical laminoplasty should be carefully determined in patients with cervical anterolisthesis. LEVEL OF EVIDENCE: 4.

Hemostatic function to regulate perioperative bleeding in patients undergoing spinal surgery: A prospective observational study.

Although bleeding is a common complication of surgery, routine laboratory tests have been demonstrated to have a low ability to predict perioperative bleeding. Better understanding of hemostatic function during surgery would lead to identification of high-risk patients for bleeding. Here, we aimed to elucidate hemostatic mechanisms to determine perioperative bleeding. We prospectively enrolled 104 patients undergoing cervical spinal surgery without bleeding diathesis. Blood sampling was performed just before the operation. Volumes of perioperative blood loss were compared with the results of detailed laboratory tests assessing primary hemostasis, secondary hemostasis, and fibrinolysis. Platelet aggregations induced by several agonists correlated with each other, and only two latent factors determined inter-individual difference. Platelet aggregability independently determined perioperative bleeding. We also identified low levels of plasminogen-activator inhibitor-1 (PAI-1) and α2-plasmin inhibitor to be independent risk factors for intraoperative and postoperative bleeding, respectively. Most important independent factor to determine postoperative bleeding was body weight. Of note, obese patients with low levels of PAI-1 became high-risk patients for bleeding during surgery. Our data suggest that bleeding after surgical procedure may be influenced by inter-individual differences of hemostatic function including platelet function and fibrinolysis, even in the patients without bleeding diathesis.

Preoperative predictors of patient satisfaction with outcome after cervical laminoplasty.

Study design Prospective cohort study. Objective The purpose of the present study was to identify the predictors of patient satisfaction with outcome after cervical laminoplasty for compressive cervical myelopathy. Methods A cohort of 143 patients with compressive myelopathy who underwent cervical double-door laminoplasty between 2008 and 2011 was studied prospectively. The principal outcome was patient satisfaction with outcome at 1 year after surgery. Patient satisfaction was graded on an ordinal scale from 1 to 7. Subjective health-related quality of life (QOL) and objective disease-specific outcome was measured by Short Form-36 (SF-36) and the Japanese Orthopaedic Association (JOA) score, respectively, before surgery and at 1-year follow-up. We evaluated the association between patient satisfaction at 1-year follow-up and various baseline parameters, including patient demographics, duration of symptoms, comorbidities, imaging findings, JOA score, and SF-36 scores. Results A total of 116 patients completed subjective and objective follow-up for a minimum of 1 year. Of 116 patients, 95 patients (81.9%) were satisfied with the outcome ("satisfied a little" or more). The unsatisfied group ("neutral" or less) showed significantly lower baseline SF-36 scores in bodily pain (BP), general health perceptions (GH), and vitality (VT) domains compared with the satisfied group. At the 1-year follow-up, SF-36 scores showed significant differences between the groups in all eight domains, whereas the JOA score showed no significant difference. Conclusions Lower baseline QOL measured by SF-36 scores, specifically in BP, GH, and VT domains, are associated with lower satisfaction with outcome after cervical laminoplasty.

Ultrasonographic quantification of spinal cord and dural pulsations during cervical laminoplasty in patients with compressive myelopathy.

PURPOSE: Pulsatile movements of the dura mater have been interpreted as a sign that the cord is free within the subarachnoid space, with no extrinsic compression. However, the association between restoration of pulsation and adequate decompression of the spinal cord has not been established. The present study investigated the relationship between the extent of spinal cord decompression and spinal cord and dural pulsations based on quantitative analysis of intraoperative ultrasonography (US). METHODS: Eighty-five consecutive patients (55 males, 30 females; mean age, 64 ± 13 years) who underwent cervical double-door laminoplasty to relieve compressive myelopathy were enrolled. Spinal cord decompression status was classified as: Type 1 (non-contact), the subarachnoid space was retained on the ventral side of the cord, Type 2 (contact and apart), the cord showed both contact with and separation from the anterior element of the cervical spine, or Type 3 (contact), the cord showed continuous contact with the anterior element of the cervical spine. Spinal cord and dura mater dynamics were quantitatively analyzed using automatic video-tracking software. Furthermore, the intensity of spinal and dural pulsation was compared with the recovery of motor function at 1 year after surgery as measured by increase in the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). RESULTS: Spinal cord pulsation amplitude ranged from 0.01 to 0.84 mm (mean 0.30 ± 0.16 mm) and dural pulsation amplitude ranged from 0.01 to 0.38 mm (mean 0.14 ± 0.08 mm). Average spinal cord pulsation amplitude in Type 2 patients was significantly larger than that in the other groups, whereas, average dural pulsation amplitudes were similar for all three groups. There was a significant correlation between spinal cord and dural pulsation amplitudes in Type 1 patients, but not in Type 2 or Type 3 patients. Type 3 patients showed a particularly poor correlation between spinal cord and dural pulsations. Spinal cord pulsation amplitude was moderately correlated with the recovery of motor function evaluated by JOACMEQ. CONCLUSION: The present results suggest that restoration of dural pulsation is not an adequate indicator of sufficient decompression of the spinal cord following a surgical procedure.

Treadmill training for hindlimb transplanted rats.

Functional improvement is an important concern for a composite allograft with motor function. As the procedure of rat composite limb transplantation is a well-established model, we focused on the effects of rehabilitation using this model. We performed the rat hindlimb transplantation in syngenic combination using a modified method confirming the processes of vessel anastomosis step-by-step that maintains good vascular patency. We studied the impact of treadmill training on hindlimb transplantated rats using Rodent Robot 3000 (Robomedica). Functional recovery was evaluated electro-physiologically after training. All transplants were conducted successfully. The "drop foot" condition improved in rats that were subjected to a training program. However, there were no significant differences in muscle atrophy improvement or denervation potential as determined by electromyography. This study is the first to detail the effects of rehabilitation on rat limb transplantation. This model is useful for the study of functional improvement for limb transplantation.

An ultrastructural study on the ligamentum flavum of the cervical spine in patients with ossification of the posterior longitudinal ligament.

Some histological analyses of the ossification of the posterior longitudinal ligament (OPLL) have been reported, but no ultrastructural studies of the ligamentum flavum (LF) in patients with OPLL have been published to date. To understand the pathology of the ossification of the spinal ligament, we examined, by electron microscopy, ultrastructural changes in the LF in cases of OPLL and made a comparison with the LF in cervical spondylotic myelopathy (CSM). Subjects were three men and two women with cervical OPLL who underwent longitudinal spinous process-splitting laminoplasty. During surgery, a small piece of the LF was collected from C2-C3 to C7-T1 and was then analyzed by light and electron microscopy. We observed atrophic elastic bundles with a two-layer structure and disarrangement, a partially torn area, the disappearance of microfibrils, and an enlarged interstitium with an irregular alignment of collagen fibrils. We observed some properties of a cell preceding its death: the initial phase may be the disappearance of the plasma-membrane, followed by the scattering of many organellae around its degenerated nucleus. Finally, many extracellular plasma membrane-invested particles that resemble matrix vesicles remain there without phagocytosis. These results suggest that ultrastructural abnormalities exist in the spinal ligament in cases of ossification of the spinal ligament.

Cervical muscle strength after laminoplasty.

To determine changes in cervical muscle strength after laminoplasty and to evaluate the relation between muscle strength and neck pain, we measured maximum isometric muscle strength using a handheld dynamometer. We also investigated neck pain before surgery and every month after surgery in 21 subjects who had undergone French-door laminoplasty. Muscle strength decreased particularly 1 month after surgery, the extensor muscles being affected more than the flexors. The strength of both muscle groups increased gradually; and at 1 year after surgery they had regained their presurgical status. All of the subjects complained of severe neck pain after 1 month. Their complaints began to decrease a few months after surgery, although they were still present in nine patients at 1 year after surgery. The correlation between muscle strength and neck pain was strongly negative for extension and flexion in men and for extension in women. No correlation was found between flexor muscle strength and neck pain in women. The extension/flexion ratio was significantly high in the neck pain group 1 year after surgery. Our results suggest that symptoms within a few months after surgery are due to surgical trauma to the soft tissues but that chronic neck pain derives from an imbalance of the two muscle strengths.