RESUMEN
Robotics in medicine is associated with precision, accuracy, and replicability. Several robotic systems are used in spine surgery. They are all considered shared-control systems, providing "steady-hand" manipulation instruments. Although numerous studies have testified to the benefits of robotic instrumentations, they must address their true accuracy. Our study used the Mazor system under several situations and compared the spatial accuracy of the pedicle screw (PS) insertion and its planned trajectory. We used two cadaveric specimens with intact spinal structures from C7 to S1. PS planning was performed using the two registration methods (preopCT/C-arm or CT-to-fluoroscopy registration). After planning, the implant spatial orientation was defined based on six anatomic parameters using axial and sagittal CT images. Two surgical open and percutaneous access were used to insert the PS. After that, another CT acquisition was taken. Accuracy was classified into optimal, inaccurate and unacceptable according to the degree of screw deviation from its planning using the same spatial orientation method. Based on the type of spatial deviation, we also classified the PS trajectory into 16 pattern errors. Seven (19%) out of 37 implanted screws were considered unacceptable (deviation distances > 2.0 mm or angulation > 5°), and 14 (38%) were inaccurate (> 0.5 mm and ≤ 2.0 mm or > 2.5° and ≤ 5°). CT-to-fluoroscopy registration was superior to preopCT/C-arm (average deviation in 0.9 mm vs. 1.7 mm, respectively, p < 0.003), and percutaneous was slightly better than open but did not reach significance (1.3 mm vs. 1.7 mm, respectively). Regarding pattern error, the tendency was to have more axial than sagittal shifts. Using a quantitative method to categorize the screw 3D position, only 10.8% of the screws were considered unacceptable. However, with a more rigorous concept of inaccuracy, almost half were non-optimal. We also identified that, unlike some previous results, the O-arm registration delivers more accurate implants than the preopCT/C-arm method.
Asunto(s)
Tornillos Pediculares , Cirugía Asistida por Computador , Humanos , Imagenología Tridimensional , Tomografía Computarizada por Rayos X , FluoroscopíaRESUMEN
OBJECTIVE: Lumbosacral pseudoarthrosis is a common complication following adult spine deformity (ASD) surgery. This study assessed the reoperation rate for L5-S1 pseudoarthrosis in the ASD population. Compared with transforaminal lumbar interbody fusions (TLIFs), we hypothesized that anterior lumbar interbody fusion (ALIF) would result in lower rates of L5-S1 pseudarthrosis. METHODS: This is a single center study with patient data retrieved from a prospective ASD database. The patients had a long-segment fusion, ALIF or TLIF at the L5-S1 level with a 2-year follow-up and were divided into 2 groups (TLIF and ALIF). The study's primary outcome was to assess the difference in the reoperation rate for clinical pseudoarthrosis between the TLIF and the ALIF groups. The secondary outcomes measured the radiological pseudoarthrosis rate and identified risks for L5-S1 pseudoarthrosis development. RESULTS: A total of 100 patients were included; 49 patients (mean age, 62.9 years; 77.5% females) were in TLIF and 51 patients (mean age, 64.4 years; 70.6% females) were in the ALIF group. Baseline characteristics were similar in both groups. Thirteen (13%) patients with L5-S1 pseudoarthrosis required reoperation. Clinical pseudoarthrosis was higher in the TLIF group than in the ALIF group (12/49 vs. 1/51; P < 0.001). Univariate analysis demonstrated a higher risk of L5-S1 pseudoarthrosis with TLIF than ALIF (risk ratio, 12.4; 95% confidence interval: 1.68-92.4; P < 0.001). Multivariate analysis revealed 4.86 times the risk of L5-S1 clinical pseudoarthrosis with TLIF than with ALIF (risk ratio, 4.86; 95% confidence interval 0.57-47; P = 0.17), but this ratio did not reach statistical significance. CONCLUSIONS: No difference in reoperation risk for L5-S1 pseudarthrosis was observed based on the method of IF. rhBMP-2 was noted as a significant predictor.
Asunto(s)
Seudoartrosis , Fusión Vertebral , Femenino , Humanos , Adulto , Persona de Mediana Edad , Masculino , Fusión Vertebral/efectos adversos , Fusión Vertebral/métodos , Vértebras Lumbares/cirugía , Seudoartrosis/etiología , Seudoartrosis/cirugía , Estudios Retrospectivos , Estudios Prospectivos , Resultado del TratamientoRESUMEN
The same correspondence between general mechanics and civil engineering is true for biomechanics and surgical implants. Currently, numerous mechanical processes are required until a prosthesis is offered to its target audience. These processes typically require human or animal vertebrae, as well as all the complexity involving such tissues, for example, an ethics committee, the availabilityofmaterials, etc. Thus,finite elementmodels (FEMs) havebecome a great option to carry out biomechanical tests independently from anatomical specimens, and, at the same time, to obtain mathematical data to assist in the general physical understanding. The present review discusses the mechanical principles involved in bioengineering, clarifies the steps for the development of FEMs, and shows application scenarios for thesemodels. To the knowledge of the authors, the present paper is the first review study in Portuguese aimed to health care professionals in a language accessible to them.
Asunto(s)
Columna Vertebral/fisiología , Fenómenos Biomecánicos , Análisis de Elementos Finitos , Tornillos Pediculares , Prótesis e ImplantesRESUMEN
A estenose do canal vertebral lombar (ECL) é uma patologia complexa, com alta incidência entre pessoas acima de 65 anos de idade. No entanto, o diagnóstico correto é, por vezes, difícil de ser confirmado. O uso de modelos de Inteligência Articial (IA) na medicina é, em geral, desconhecida para a maioria da comunidade médica, mas tem sido usada há décadas na assistência em UTI, os métodos de imagem e dispositivos de diagnóstico eletrônico (ECG). Através de uma revisão sistemática da literatura, com foco nos achados clínicos e radiológicos, juntamente com todas as modalidades de tratamento, foi possível identicar o ambiente completo de pacientes LSS, para responder a quatro questões: (a) "Com base no quadro clínico, o paciente tem um, cenário moderado ou grave?"; (b) "Com base nos dados radiológicos, o paciente pode ser classicado com um cenário leve,moderada ou grave?"; (c) "Qual é a probabilidade, com base na anamnese, do paciente ter ECL?"; (d) "Qual é o melhor tratamento a ser oferecido?".þ. Como auxílio de um software usando Sistema Especialista (Expert Sinta), uma linguagem de IA, alocamos todas as variáveis e seus valores para orientar o software responder às quatro perguntas. Foi possível identicar 657 artigos cientícos, no entanto apenas 63 poderia mencionar não apenas as variáveis, mas a sua probabilidade de ocorrência ou teve disponibilidade texto completo. Foi possível classicar a intensidade do quadro clínico e radiológico, criar um índice de probabilidade para LSS e oferecer o melhor tratamento. Recomendamos o uso, sob supervisão médica, em de Neurocirurgia ou clínicas ortopédicas como um conselheiro para os pacientes com ELA.
The lumbar spinal stenosis (LSS) is a complex pathology with high incidence among people above 65 years old. However, the correct diagnose is sometimes difcult to perform. The use of Articial Intelligence (AI) models in medicine is, in general, unfamiliar for the majority of medical community, but has been used for decades in assistance in ICUs, image methods and electronic diagnostic devices (EKG). Through a systematic literature review focused in the clinical and radiological ndings, in addition to all treatmentmodalities, we identied the complete environment of LSS patients, to answer four questions. (a) "Based on the clinical presentation, the patient has a mild, moderate or severe scenario?", (b) "Based on the radiological data, the patient can be classied having a mild, moderate or severe scenario?", (c) "What is the probability, based on the anamneses, the patient has LSS?", and (d) "What is the best treatment to be offered?".With the aid of a software using Expert System (Expert Sinta), a language of AI, we allocate all the variables and their values to orient the software to answer the four questions. It was possible to identify 657 scientic articles, however only 63 could mention not only the variables, but their occurrence probability or had full text availability. It was possible to classify the intensity the clinical and radiological scenario, create a probability index for LSS and offer the best treatment. We recommend the use, under medical supervision, in neurosurgery or orthopedic clinics as an adviser for patients with LSS.
Asunto(s)
Humanos , Estenosis Espinal/diagnóstico , Estenosis Espinal/terapia , Sistemas Especialistas , Inteligencia Artificial , Vértebras LumbaresRESUMEN
BACKGROUND AND PURPOSE: Hypothermia has been shown to be neuroprotective in a variety of clinical settings. Unfortunately, poor delivery techniques and insufficient data in appropriate preclinical models have hampered its development in human stroke. To address these limitations, we have devised a 10F intravascular catheter capable of rapid systemic cooling of nonhuman primates. METHODS: Placed in the inferior vena cava via a transfemoral approach, the catheter was used to induce mild systemic hypothermia 3 hours after the onset of hemispheric stroke in baboons. RESULTS: Cooling was achieved at a rate of 6.3+/-0.8 degrees C/h. Target brain temperatures (32.2+/-0.2 degrees C) were reached at the same time (47.7+/-6.32 minutes) as target esophageal temperatures (32.0+/-0.0 degrees C). Hypothermia was maintained for 6 hours in all animals. Animals did not experience the infections, coagulopathy, or cerebral edema commonly seen with surface cooling methods in human stroke. CONCLUSIONS: These data suggest that a brief episode of mild core hypothermia instituted at a clinically relevant time point can be achieved in primate stroke and that our intravascular cooling technique provides safe, rapid, and reproducible hypothermia.