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Background Many studies have been conducted on the biomechanics of the spine to elucidate the fixation properties of spinal fusion surgery and the causes of instrumentation failure. Among these studies, there are some studies on load sharing in the spine and measurement using strain gauges and pressure gauges, but there is a lack of research on axial compressive loads. Methods Axial compressive load tests were performed on human cadaveric injured lumbar vertebrae fixed with pedicle screws (PS). Both the strain generated in the PS rod and the intradiscal pressure were measured. Subsequently, the stress generated in the PS rod and the load sharing of the spine and instrumentation were calculated. Results Even when only compressive load is applied, bending stress of more than 10 times the compression stress was generated in the rod, and the stress tended to concentrate on one rod. Rod deformation becomes kyphotic, in contrast to the lordotic deformation behavior of the lumbar spine. The stress shielding rate was approximately 40%, less than half. Conclusions This study obtained basic data useful for constructing and verifying numerical simulations that are effective for predicting and elucidating the causes of dislodgement and failure of spinal implants.
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INTRODUCTION: A posterior-only total en bloc spondylectomy (TES) of the L3 level was deemed a highly intricate surgical procedure, necessitating the preservation of the L3 nerve root to prevent neurological deterioration. Despite bilateral preservation efforts of the L3 nerve roots, neurological deterioration proved unavoidable. This study aims to present the clinical, neurologic, and oncologic outcomes of spinal metastasis patients who underwent a posterior-only approach TES, encompassing the L3 vertebra. MATERIALS AND METHODS: All patients with L3-involved spinal metastasis undergoing posterior TES between January 2018 and January 2022 were investigated. The primary outcomes considered were the local recurrence rate and manual muscle testing of the lumbar myotome. Secondary outcomes included Frankel neurological status, operative time, blood loss, perioperative and postoperative complications, and Eastern Cooperative Oncology Group score. RESULTS: Five patients with TES involving L3 (three females) met the inclusion criteria. All patients had solitary metastases (three in the lungs, 2 in the breasts). Postoperatively, all patients experienced weakness of the hip flexors, but they were able to ambulate independently 12 months after surgery. One patient exhibited adjacent segment (L2) disease progression and underwent corpectomy 18 months after TES. No local recurrences at the surgical site were detected on magnetic resonance imaging at the 1-year follow-up. CONCLUSION: Posterior-only TES for L3-involved vertebrae yielded excellent results in the local control of metastatic disease. Despite hip flexor weakness, all patients were able to regain independent ambulation after 12 months. TES can offer favorable clinical and oncological outcomes in patients with solitary spinal metastases.
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Neoplasias da Coluna Vertebral , Feminino , Humanos , Neoplasias da Coluna Vertebral/patologia , Estudos Retrospectivos , Vértebras Lombares/cirurgia , Vértebras Lombares/patologia , Imageamento por Ressonância MagnéticaRESUMO
AIMS: Implant failure in allograft reconstruction is one of the most common problems after treating a large bone defect for a primary bone tumor. The study aimed to investigate the effect of bone cement augmentation with different configurations of dual locking plates used for femoral allograft fixation. METHODS: Four finite element (FE) models of the femur with a 1-mm bone gap were developed at the midshaft with different configurations of the 10-hole fixation dual locking plate (LP) with and without intramedullary bone cement augmentation. Model 1 was the dual LP at the lateral and medial aspect of the femur. Model 2 was Model 1 with bone cement augmentation. Model 3 was the dual LP at the anterior and lateral aspect of the femur. Finally, Model 4 was Model 3 with bone cement augmentation. All models were tested for stiffness under axial compression as well as torsional, lateral-medial, and anterior-posterior bending. In addition, the FE analyses were validated using biomechanical testing on a cadaveric femur. RESULTS: Model 2 had the greatest axial compression stiffness, followed by Models 1, 4, and 3. Bone cement augmentation in Models 2 and 4 had 3.5% and 2.4% greater axial stiffness than the non-augmentation Models 1 and 3, respectively. In the bone cement augmentation models, Model 2 had 11.9% greater axial compression stiffness than Model 4. CONCLUSION: The effect of bone cement augmentation increases construct stiffness less than the effect of the dual LP configuration. A dual lateral-medial LP with bone cement augmentation provides the strongest fixation of the femur in terms of axial compression and lateral bending stiffness.
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Cimentos Ósseos , Fraturas do Fêmur , Humanos , Análise de Elementos Finitos , Fixação Interna de Fraturas/métodos , Fraturas do Fêmur/cirurgia , Fêmur/cirurgia , Fêmur/patologia , Placas Ósseas , Aloenxertos , Fenômenos BiomecânicosRESUMO
AIM: To demonstrate a single posterior approach, total en bloc spondylectomy (TES) could be performed safely without preoperative embolization in spinal metastasis patients. MATERIALS AND METHODS: Thirteen solitary spinal metastasis patients (five males) underwent single posterior approach TES at the thoracolumbar spine without preoperative embolization from January 2018 to January 2020. The primary sites were the breast (n = 4), hepatocellular carcinoma (n = 2), colon (n = 2), and others (n = 5). All patients underwent single posterior TES. The Eastern Cooperative Oncology Group, Frankel neurological status, operative time and blood loss, and any complications were all recorded. The patients were regularly followed-up with radiography, computed tomography, and magnetic resonance imaging to detect any local recurrences. RESULTS: The mean operative time was 354.6 min, and the mean operative blood loss was 2134.62 ml. None of the patients experienced any perioperative complications. Within the follow-up period (3-24 months), no local recurrences were detected. Two patients (15.38%) were found to have distant metastasis to adjacent and remote vertebrae. Three patients were lost to follow-up, and three patients died of disease. Six patients showed an improved ECOG functional status by at least one grade. Four of Frankel A patients improved their neurological status by at least one grade. CONCLUSION: Even without embolization, single posterior TES at the thoracolumbar spine is safe and effective for short-term local control in solitary spinal metastasis. However, TES cannot prevent distant metastasis. Longer-term follow-up studies will be able to further identify the benefits of TES for the long-term local control of diseases.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Neoplasias da Coluna Vertebral , Masculino , Humanos , Neoplasias da Coluna Vertebral/diagnóstico por imagem , Neoplasias da Coluna Vertebral/cirurgia , Tailândia , Imageamento por Ressonância Magnética , Estudos RetrospectivosRESUMO
Introduction: Various syndesmotic fixation methods in ankle injury are recommended; however, a lack of biomechanical information persists regarding the stiffness of the fixation methods. The current study thus aimed to assess biomechanical cadaveric validation and perform a finite element analysis of syndesmotic fixation comparing endobutton vs. screw after syndesmotic injury with an ankle fracture. Method: Five pairs of ankles of fresh cadavers were used for the validity test for Anterior Inferior Tibiofibular Ligament (AITFL), Posterior Inferior Tibiofibular Ligament (PITFL), and Interosseous ligament biomechanics properties. Four finite element models (FEM) were created: an intact model, a fracture model with/without syndesmotic injury, an endobutton fixation model, and a syndesmotic screw fixation model. Each FEM was tested vis-à-vis external rotation force, anteroposterior translation force, and compression force until model failure. The primary outcomes were stiffness and force until failure. Result: The respective anteroposterior translation force for the stiffness of the intact model, the screw fixation model, and the endobutton fixation was 8.14, 9.15, and 8.17 N/mm. The respective external rotation force for the stiffness of intact, screw fixation, and endobutton model was 0.927,0.949, and 0.940 Nm/degree. The respective stress under compression force in the intact, screw fixation, and endobutton model was 39.94,25.59, and 37.30 MPa. Conclusion: Both screw and endobutton fixation models provided more translation, compression, and rotation stability than normal syndesmosis, but the screw model provided greater translation and compression force stability than the endobutton model. There was no difference in rotational stability between the two models. We thus recommend the same rehabilitation protocol for both fixation methods; however, vigorous translation and compression should be avoided when using endobutton fixation.
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Background: There is no research about current experiences of orthopaedic residents in Thailand and Myanmar. Methods: A questionnaire survey was distributed among Thai and Myanmar orthopaedic residents to assess their current experiences. This study included a total of 168 participants, comprising 92 orthopaedic residents in Thailand, and 76 in Myanmar who answered the questionnaire. The survey comprised nine questions about issues such as the contents of residency training programs, current training satisfaction, and future careers. The survey was administered anonymously between October 2020 and January 2021. Results: Regarding training content, 24 residents (14.3%) reported being "very satisfied", 103 (61.3%) were "satisfied", 37 (22.0%) were "moderately satisfied", and four (2.4%) were "dissatisfied", and respondents spent a mean of 3.1 h/day reading textbooks and research papers. As for salary, five (3.0%) residents answered "satisfied", 46 (27.4%) responded "moderately satisfied", and 117 (69.6%) were "dissatisfied". Conclusions: Many orthopedic residents in Thailand and Myanmar were enthusiastic about and satisfied with their training. Their only problem was that the salary was low.
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There have been no studies comparing the outcomes of nonvascularized autograft (NA) and allograft after resection of primary bone tumors. This study compares the clinical, functional outcomes of NA and allograft reconstruction and analyzes the risk factors for failure after these procedures. A retrospective study of patients with primary bone tumors of the extremities who underwent NA (n = 50) and allograft reconstruction (n = 47). The minimum follow up time was 24 months. The mean time to union for the NA and allograft group was 9.8 ± 2.9 months and 11.5 ± 2.8 months, respectively (p = 0.002). Reconstruction failure in the NA and allograft group was 19 (38%) and 26 (55.3%), respectively. Nonunion (30%) was the most common complication found in the NA group, while structural failure (29.8%) was the most common in the allograft group. There was no significant difference in functional outcome in terms of the mean Musculoskeletal Tumor Society score between the NA and allograft groups (23.5 ± 2.8 and 23.9 ± 2.1, respectively, p = 0.42). Age, sex, tumor location, graft length, method of reconstruction did not significantly influence failure of reconstruction. Chemotherapy was the only significant risk factor affecting outcomes (HR = 3.49, 95% CI = 1.59-7.63, p = 0.002). In the subgroup analysis, the use of chemotherapy affected graft-host nonunion (p < 0.001) and structural failure in both the NA and allograft groups (p = 0.02). Both NA and allograft reconstruction methods provide acceptable clinical and functional outcomes. Chemotherapy is a risk factor for failure of both reconstructions, particularly graft-host nonunion and structural failure.
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Neoplasias Ósseas , Transplante Ósseo , Aloenxertos/patologia , Autoenxertos/patologia , Neoplasias Ósseas/patologia , Transplante Ósseo/efeitos adversos , Transplante Ósseo/métodos , Humanos , Estudos Retrospectivos , Fatores de Risco , Resultado do TratamentoRESUMO
Background: Pleomorphic liposarcoma (PLPS) accounts for less than 5% of liposarcoma, and its metastasis to bone is rare. As a high-grade tumor, PLPS is reported to be more invasive with high local recurrence and distant metastasis. Here, we report a case of PLPS of the femur and undertake a review of the literature. Case Presentation. A 58-year-old man presented with a big mass at posterior aspect of his left thigh. The computed tomography of the chest for staging revealed two nodules at the left upper lung field. Wide resection of the soft tissue mass at the left thigh was performed by a general surgeon. Thoracotomy and wedge resection of the lung nodules was carried out by a cardiothoracic surgeon. Pathologic diagnosis suggested PLPS. Three years later, he was presented with sudden right hip pain after he slipped. The plain radiograph revealed an osteolytic lesion at the right proximal femur with minimally displaced pathological fracture. The MRI showed the presence of a tumor at the proximal part of the right femur and its soft tissue invasion. The patient underwent en bloc proximal femur wide resection followed by cemented long-stem bipolar hemiarthroplasty. The final histopathology report from definite surgery specimen revealed pleomorphic spindle, round, and polygonal cells arranged in sheets, short fascicles, and storiform arrays. There were no complications, adverse outcomes, or recurrence reported at six months after surgery. The patient could walk without gait aid and had good functional outcomes according to the TESS questionnaire. Conclusion: PLPS is a highly aggressive tumor with a high distant metastatic rate. The definite diagnosis of PLPS is made on the basis of histopathology. Surgical treatment involving wide resection that aims to achieve a negative margin is the best option currently available, and we recommend treating bone metastasis from PLPS as the primary site of the tumor. The effect of chemotherapy and radiotherapy in preventing postoperative recurrence is still unclear and requires further studies.
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AIM: The biological reconstruction of the knee with osteoarticular allografts and resection arthrodesis have been reported but there has not yet been a direct comparison between both these procedures. This study aimed to identify the prognostic factors that influence failure of biological reconstruction and compared the results between both procedures. METHODS: Between 1994 and 2017, we performed 92 limb-sparing procedures using resection arthrodesis (n = 53) and osteoarticular allograft reconstruction (n = 39) for the management of primary bone tumors around the knee. The minimum follow-up time was 2 years in both groups. RESULTS: The failure rate of reconstruction in the osteoarticular allograft and resection arthrodesis group was 48.7% and 39.6%, respectively (p = 0.75). The mean MSTS score in the osteoarticular allograft and resection arthrodesis group was 23.7 and 21.8, respectively (p = 0.01). The significant risk factor for failure after biological reconstruction was the administration of chemotherapy (p = 0.001; HR = 3.39; 95% CI, 1.60-7.17). CONCLUSION: Patients who underwent osteoarticular allograft had a better functional outcome than those who underwent resection arthrodesis reconstruction, but clinical outcomes between the groups were comparable. Chemotherapy is a significant adverse prognostic factor for failure of biological reconstruction.
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Neoplasias Ósseas , Transplante Ósseo , Aloenxertos/patologia , Aloenxertos/transplante , Artrodese/efeitos adversos , Neoplasias Ósseas/patologia , Transplante Ósseo/efeitos adversos , Transplante Ósseo/métodos , Humanos , Prognóstico , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Biological reconstruction is widely used to reconstruct bone defects after resection of bone tumors in the extremities. This study aimed to identify risk factors for failure and to compare outcomes of the allograft, nonvascularized autograft, and recycled frozen autograft reconstruction after resection of primary malignant bone tumors in the extremities. A retrospective study was performed at a single center between January 1994 and December 2017. Ninety patients with primary malignant bone tumors of the extremities were treated with tumor resection and reconstruction using one of three bone graft methods: nonvascularized autograft (n = 27), allograft (n = 34), and recycled frozen autograft (n = 29). The median time for follow-up was 59.2 months (range 24-240.6 months). Overall failure of biological reconstruction occurred in 53 of 90 patients (58.9%). The allograft group had the highest complication rates (n = 21, 61.8%), followed by the recycled frozen autograft (n = 17, 58.6%) and nonvascularized autograft (n = 15, 55. 6%) groups. There was no statistically significant difference among these three groups (p = 0.89). The mean MSTS score was 22.6 ± 3.4 in the nonvascularized autograft group, 23.4 ± 2.6 in the allograft group, and 24.1 ± 3.3 in the recycled frozen autograft group. There was no significant difference among the groups (p = 0.24). After bivariate and multivariable analyses, patient age, sex, tumor location, graft length, methods, and type of reconstruction had no effects on the failure of biological reconstruction. Biological reconstruction using allograft, nonvascularized autograft, and recycled frozen autograft provide favorable functional outcomes despite high complication rates. This comparative study found no significant difference in functional outcomes or complication rates among the different types of reconstruction.
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Neoplasias Ósseas/cirurgia , Transplante Ósseo/métodos , Procedimentos de Cirurgia Plástica/métodos , Adolescente , Adulto , Aloenxertos , Braço , Autoenxertos/cirurgia , Transplante Ósseo/efeitos adversos , Criança , Feminino , Humanos , Perna (Membro) , Masculino , Pessoa de Meia-Idade , Procedimentos de Cirurgia Plástica/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Falha de Tratamento , Adulto JovemAssuntos
Ortopedia , Humanos , Japão/epidemiologia , Mianmar/epidemiologia , Inquéritos e Questionários , TailândiaRESUMO
ABSTRACT: Case-control studies by examining the lumbar spine computed tomography (CT) findings focusing on the spinous processes."Passing spine" was defined as a lumbar degenerative change observed on CT images. In contrast, kissing spine, which is also an image finding, has been acknowledged as an established clinical condition. Therefore, we compared the passing spine group and the kissing spine group to investigate whether the 2 groups belong to a similar disease group; this would help explain the clinical and imaging characteristics of patients with passing spine.Previous studies have described the gradual increase in the height and thickness of the lumbar vertebral spinous processes that can occur in individuals aged >40âyears, and reported that this progressive degeneration can lead to a condition termed "kissing spine."We examined the CT imaging of 373 patients with lumbar spinal disease and divided patients into 2 groups, the kissing spine (K) group and the passing spine (P) group, and compared the clinical (age, sex, presence/absence of lower extremity pain) and imaging data (localization of kissing or passing spine, intervertebral disc height at the level of kissing or passing spine, lumbar lordosis (LL) angle, presence/absence of vacuum phenomenon (VP) in the intervertebral discs and spondylolisthesis at the level of kissing or passing spine between the 2 groups.Compared with patients with kissing spine, patients with passing spine had an increased incidence of lower extremity pain, lower intervertebral disc height at the level of passing spine, relatively static LL, and VP commonly observed in the intervertebral discs at the level of passing spine.Because the clinical and imaging characteristics of patients with passing spine are different from those of patients with kissing spine, passing spine might be a pathological condition distinct from kissing spine.
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Degeneração do Disco Intervertebral/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Região Lombossacral/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Corpo Vertebral/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Humanos , Disco Intervertebral/patologia , Lordose/diagnóstico por imagem , Extremidade Inferior/patologia , Vértebras Lombares/patologia , Região Lombossacral/patologia , Masculino , Pessoa de Meia-Idade , Transtornos Somatoformes/diagnóstico , Transtornos Somatoformes/epidemiologia , Espondilolistese/diagnóstico por imagem , Corpo Vertebral/patologiaRESUMO
This study aims to evaluate the mechanical performance of custom 3D-printed titanium plates in the treatment of distal humerus fractures. Rigidity of four plating configurations were investigated by finite element analysis. The results reveal that implementation of custom designs with minimal screw holes, lateral-medial linking screw and lateral brim could significantly improve stiffness and consequently leads to better biomechanical stability as compared to standard osteosynthesis design. Biomechanical testing was also performed to validate practical usability. The results confirm that newly designed custom plates fabricated by selective laser melting is a possible alternative for the treatment of distal humerus fracture.
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Placas Ósseas , Úmero/cirurgia , Lasers , Fenômenos Biomecânicos , Análise de Elementos Finitos , Fixação Interna de Fraturas/métodos , Humanos , Estresse MecânicoRESUMO
OBJECTIVE: To investigate the neurological recovery of Frankel A spinal giant cell tumor (GCT) patients after they had received a Total En Bloc Spondylectomy (TES). MATERIALS AND METHODS: We retrospectively recorded data of three patients (two females) with mobile spine GCT (T6, T10, and L2) Enneking stage III with complete paralysis before surgery, who had undergone TES in our institute from January 2018 to September 2020. The duration of neurologic recovery to Frankel E was the primary outcome. The intra-operative blood loss, operative time, operative-related complications, and the local recurrence were the secondary outcomes. RESULTS: The duration of suffering from Frankel A to TES surgery was 2 months for the T6 patient, 3 weeks for the T10 patient, and 1 month for the L2 patient. Three patients had achieved full neurological recovery to Frankel E within 6 months after TES (T6 for 5 months, T10 for 3 months, and L2 for 3 months). The average blood loss was 2833.33 ml and the mean operative time was 400 min. Up until the last follow-up (13-25 months), no evidence of local recurrences had been found in any of the three patients. CONCLUSION: Frankel A spinal GCT patients can achieve full neurological recovery after TES, if the procedure is performed within 3 months after complete paraplegia. TES can effectively control any local recurrences.
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Neoplasias Ósseas/cirurgia , Discotomia/métodos , Tumor de Células Gigantes do Osso/cirurgia , Paralisia/cirurgia , Neoplasias da Coluna Vertebral/cirurgia , Adulto , Neoplasias Ósseas/complicações , Feminino , Seguimentos , Tumor de Células Gigantes do Osso/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/prevenção & controle , Paralisia/etiologia , Estudos Retrospectivos , Neoplasias da Coluna Vertebral/complicações , Coluna Vertebral/cirurgia , Resultado do TratamentoRESUMO
PURPOSE: There is little information available regarding the cage diameter that can provide the most rigid construct reconstruction after total en bloc spondylectomy (TES). The aim of this study was thus to determine the most appropriate titanium mesh cage diameter for reconstruction after spondylectomy. METHODS: A finite element model of the single level lumbar TES was created. Six models of titanium mesh cage with diameters of 1/3, 1/2, 2/3, 3/4, 4/5 of the caudad adjacent vertebra, and 1/1 of the cephalad vertebra were tested for construct stiffness. The peak von Mises stress (MPa) at the failure point and the site of failure were measured as outcomes. A cadaveric validation study also conducted to validate the finite element model. RESULTS: For axial loading, the maximum stress points were at the titanium mesh cage, with maximum stress of 44,598 MPa, 23,505 MPa, 23,778 MPa, and 16,598 MPa, 10,172 MPa, 10,805 MPa in the 1/3, 1/2, 2/3, 3/4, 4/5, and 1/1 diameter model, respectively. For torsional load, the maximum stress point in each of the cages was identified at the rod area of the spondylectomy site, with maximum stress of 390.9 MPa (failed at 4459 cycles), 141.35 MPa, 70.098 MPa, and 88.972 MPa, 42.249 MPa, 15.827 MPa, respectively. A cadaveric validation study results were coincided with the finite element model results. CONCLUSION: The most appropriate mesh cage diameter for reconstruction is 1/1 the diameter of the lower endplate of the adjacent cephalad vertebra, due to its ability to withstand both axial and torsional stress. According to the difficulty of large size cage insertion, a cage diameter of more than half of the upper endplate of the caudad vertebrae is acceptable in term of withstand stress. A cage diameter of 1/3 is unacceptable for reconstruction after total en bloc spondylectomy.
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Análise de Elementos Finitos , Vértebras Lombares/cirurgia , Osteotomia/métodos , Procedimentos de Cirurgia Plástica/métodos , Próteses e Implantes , Desenho de Prótese , Neoplasias da Coluna Vertebral/cirurgia , Telas Cirúrgicas , Titânio , Fenômenos Biomecânicos , Transplante Ósseo , Cadáver , Humanos , Estresse Mecânico , Suporte de CargaRESUMO
BACKGROUND: The L2 nerve root is considered part of the lumbar plexus that innervates the iliopsoas (IP) and quadricep muscles (Qd). Total en bloc spondylectomy (TES) at the L2 vertebra requires bilateral nerve root transection to facilitate surgical dissection and vertebral body removal. Information regarding neurological function recovery of the IP and Qd in patients with muscle weakness before TES is lacking. We aimed to report the neurological recovery of IP and Qd after TES involving the L2 vertebra in preoperative lower extremity weakness in spinal tumor patients. METHODS: We prospectively recorded all L2-involved spinal tumor patients undergoing TES between January 2018 and November 2020. As a primary outcome, we recorded the Manual Muscle Testing (MMT) grade of the IP and Qd preoperatively, immediately postoperatively, and at follow-up. Secondary outcomes included the Frankel neurological status, sensation impairment, and the Eastern Cooperative Oncology Group score. RESULTS: From 8 TES-involving L2 patients, 6 (4 males) met the inclusion criteria. One patient had first-grade deterioration of the Qd MMT immediately postoperatively. All patients could ambulate independently 6 months after surgery. Five patients required follow-up for more than 1 year and could walk without any gait aids. All patients had persistent anterior groin and bilateral thigh numbness until the final follow-up. CONCLUSION: Neurological recovery of the IP and Qd muscles as measured by MMT can occur within 6 months of bilateral L2 nerve root transection. Bilateral L2 nerve root sacrifice can have acceptable neurological outcomes and recovery, even in patients with preoperative IP and Qd weakness. LEVEL OF EVIDENCE: 4.
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STUDY DESIGN: An in vitro biomechanical study. OBJECTIVE: The purpose of this study is to discuss whether pedicle screw systems can control spinal rotational instability in a functional spinal unit of lumbar spine on human cadaver. SUMMARY OF BACKGROUND DATA: Rotational experiments using deer lumbar cadaveric models showed that rotational range of motion (ROM) of the model fixed by a pedicle screw system with crosslinking after total facetectomy for both the sides was larger than that in the intact model, and stated that spinal rotational instability could not be controlled using a pedicle screw system. METHODS: A rotation experiment using 10 functional spinal units (L3-4) of lumbar spine on human cadavers was performed by preparing the four models (intact model, damaged model, pedicle screw model, and crosslink (CL) model) in stages, then calculating and comparing rotational ROM among the four models. RESULTS: Rotational ROM in the CL model was still larger than that of the intact model in all the samples. And, rotational ROM decreased in the order of damaged model >> pedicle screw model > CL model > intact model. Statistical analysis revealed significant differences between all models (Pâ<â0.001). CONCLUSIONS: Pedicle screw systems may not control severe spinal rotational instability in human lumbar cadaveric models with total facetectomy on both the sides. This may represent a major biomechanical drawback to the pedicle screw system. LEVEL OF EVIDENCE: N/A.
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Instabilidade Articular/cirurgia , Vértebras Lombares/cirurgia , Parafusos Pediculares , Rotação , Fusão Vertebral/métodos , Idoso , Idoso de 80 Anos ou mais , Animais , Fenômenos Biomecânicos/fisiologia , Cadáver , Cervos , Feminino , Humanos , Instabilidade Articular/diagnóstico por imagem , Instabilidade Articular/fisiopatologia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/fisiopatologia , Masculino , Pessoa de Meia-Idade , Amplitude de Movimento Articular/fisiologia , Fusão Vertebral/instrumentaçãoRESUMO
BACKGROUND: Allografts and recycled bone autograft are commonly used for biological reconstruction. The dual locking plates fixation method has been advocated for increasing allograft stability and preventing fixation failure; however, the biomechanical properties of the various configurations of dual locking plates have not been extensively studied. METHODS: In a finite element (FE) analysis, we developed 6 patterns of different dual locking plate configurations for fixation of the mid shaft of the femur. The maximum strains were recorded for each of the 6 models then axial, bending and torsion stiffness were calculated. The FE analysis was validated the results with mechanical testing (axial compression, bending, and torsional stiffness) on a cadaveric femur. FINDINGS: The highest axial compression (715.41 N/mm) and lateral bending (2981.24 N/mm) was found in Model 4 (with two 10-hole locking plates placed at the medial and lateral side), while the highest torsional stiffness (193.59 N·mm /mm) was found in Model 3 (with 8- and 10-hole locking plates placed at the posterior and lateral side). Excellent agreement was found between the finite element analysis and biomechanical testing (r2 = 0.98). INTERPRETATION: The dual locking plate configuration with medial and lateral, 10-hole locking plates provided the most rigid and strongest fixation of the femur; both in terms of axial compression and lateral bending stiffness.
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Autoenxertos , Placas Ósseas , Análise de Elementos Finitos , Fixação Interna de Fraturas/instrumentação , Fenômenos Biomecânicos , Transplante Ósseo , Fêmur/lesões , Fêmur/cirurgia , HumanosRESUMO
BACKGROUND: The aim of this study was to evaluate survival of metastatic bone disease of an upper extremity, and to identify the prognostic factors that influence survival. METHODS: Patients with metastatic bone disease of an upper extremity between 2008 and 2015 were reviewed from the database of a tertiary university hospital. RESULTS: Of 102 patients, 48 males and 54 females with a median age of 61 (range, 28-82 years), the humerus (64.7%), clavicle (13.7%), and scapula (12.7%) were the common sites for bone metastasis of an upper extremity. Fifty-nine (57.8%) presented with pathologic fracture. No history of cancer was found in 76.5% of patients. The mean onset of metastatic bone disease after the first diagnosis of primary cancer was 4.74 ± 14.07 months (range, 0-84 months). Lung (31.4%) was the most common primary cancer followed by liver (14.7%), breast (12.7%), thyroid (7.8%), and renal (3.9%). Eighty-two cases (80.39%) died from the disease such that the median survival was 4.08 months (95% CI 2.57-6.17). The significant risk factors were the type of primary tumor (P < 0.001, HRâ¯=â¯4.44; 95% CI, 1.99-9.90) and ECOG performance status (Pâ¯=â¯0.021, HR = 2.11, 95% CI 1.12-3.99). CONCLUSIONS: Patients with metastatic bone disease of an upper extremity have a limited life expectancy. The type of primary tumor and ECOG performance status were the important prognostic factors that influenced overall survival. Our data help in the management of patients, families, and doctors, so as to avoid over- or under-treatment.
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The aim of this study was to perform a survival analysis of Cholangiocarcinoma (CCA) with spinal metastases. 55 cases of CCA with spinal metastases were retrospectively reviewed. We recorded age, sex, Kanofsky performance score, Frankel scale, number and region of affected vertebrae, presence of appendicular bone metastases, treatment received, and survival time; then performed a survival analysis. Overall median survival was 4months (95%CI, 2.89-5.11). Frankel A had the poorest survival (2months-95%CI, 1.15-2.85) compared to Frankel C and D (P=0.004 and <0.001, respectively). One-level spinal metastasis had the longest survival (8months-95%CI, 5.98-10.02) compared to two-level and more than two-level involvement (P=0.036 and 0.001, respectively). The higher Kanofsky score had the longer survival (11months-95%CI, 9.61-12.39) compared with the low and moderate score groups (P<0.001 and 0.012, respectively). Radiation therapy had a survival of 6months (95%CI, 3.41-8.59), significantly longer than the 3months for palliative spine surgery and 2months for palliative treatment alone. CCA resection and palliative spine surgery-when performed together and/or combined with other adjuvant treatment(s)-had a survival time of longer than 9months. In conclusion, CCA with spinal metastases had a poor median survival. A single level of affected spine, a Frankel scale of C or better, a moderate to high Kanofsky score, and radiation therapy were associated with significantly longer median survival. CCA resection and spinal surgery may play an important role in prolonging survival when used in conjunction with other adjuvant treatment modalities.