Percutaneous Pedicle Screws Positioning by means of the “Scotty Dog” Imaging Monitoring Technique in Spine Surgery: A Case Series

Abstract

Objectives Vertebrae, when looked at in x-rays with oblique incidence (45°), seem similar in shape to a Scottish Terrier dog. The "Scotty Dog" incidence is commonly used in spinal pain treatments such as radiofrequency and transforaminal blockages for correct insertion of the needle, because it allows complete visualization of the pedicle. The objective is to describe a series of cases of spinal surgery using the "Scotty Dog" monitoring technique and to evaluate safety.

Methods In this study, we describe all consecutive patients operated by the same surgeon from August 2011 to August 2012 using the "Scotty Dog" technique of fluoroscopic monitoring. Patients were operated for spondylolisthesis, lumbar canal stenosis, spinal disc herniations, and fractures. All patients underwent computed tomography (CT) after surgery to confirm the correct positioning of screws.

Results During the study period, 42 patients with a mean age of 64.5 years underwent operation, most of them for spinal disc herniation correction. In all cases, visualization of the pedicle was possible in all its length and no case of foramen invasion was registered. Surgical time was 98 minutes on average, with no need for transfusion or complications requiring admission to the ICU. There was one case of infection.

Conclusions The Scotty Dog technique for imaging monitoring of the spine provides easy visualization of the whole pedicle, allowing a safe screw insertion. In this case series, there was no case of foramen invasion.

Resumo

Objetivos As vértebras, visualizadas pela incidência oblíqua (45°) nos raios-X, têm o formato de um cão da raça Scottish Terrier. A incidência Scotty Dog é usada em tratamentos de dor na coluna, como radiofrequência e bloqueios transforaminais, para correta inserção da agulha, porque permite completa visualização do pedículo. O objetivo deste trabalho é descrever uma série de casos de cirurgia de coluna usando a técnica de monitoramento Scotty Dog e avaliar segurança.

Métodos Todos os pacientes consecutivos operados pelo mesmo cirurgião de agosto de 2011 a agosto de 2012 usando a técnica Scotty Dog de monitoramento fluoroscópico foram descritos. Pacientes foram operados devido a espondilolistese, estenose do canal vertebral, hérnias e fraturas. Todos os pacientes foram submetidos a tomografia computadorizada após a cirurgia para confirmação do correto posicionamento dos parafusos.

Resultados No período do estudo, 42 pacientes foram operados, com média de idade de 64,5 anos, a maioria para correção de hérnia de disco. Em todos os casos, a visualização do pedículo foi possível em toda a sua extensão e não foi registrado caso de invasão do forame. O tempo de cirurgia foi de 98 minutos em média, sem necessidade de transfusões ou complicações exigindo internação em unidade de terapia intensiva. Houve um caso de infecção.

Conclusões A técnica Scotty Dog de monitoramento por imagem da coluna permite fácil visualização de todo o pedículo e inserção do parafuso com segurança, com nenhum caso de invasão foraminal nesta série de casos.

Keywords

fluoroscopy - surgical diagnostic techniques - percutaneous discectomy - spine - diagnostic imaging

Palavras-chave

fluoroscopia - técnicas de diagnóstico por cirurgia - discotomia percutânea - coluna vertebral - diagnóstico por imagem

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