Scottie dog sign
Scottie dog sign is a radiological sign which refers to the appearance of lumbar spine in oblique view X-ray.[1] It was once used as a diagnostic sign in x-rays for lumbar spondylolysis, but it is not commonly in use nowadays because of the advent of more sensitive diagnostic methods such as the CT scan and MRI scan.[2]
Radiological appearance
On lumbar x-ray, a Scottie dog can be seen laterally, with the pedicle as the eye, transverse process as the nose, superior articular facet as the ear, spinous process as the body, and inferior articular facet as the front leg[3]. The pars interarticularis defect presents itself as the neck of the dog.
Clinical relevance
Risk factors
Environmental stress such as repetitive motion or weight bearing are common risk factors for developing spondylosis[4]. There's a proportionate increase in relation to age up until the age of 18. Although spondylolysis is less common in children, it's the leading cause of low back pain in adolescent athletes, especially those in spinal extension intensive sports such as gymnastic, baseball, rowing, and soccer.
Symptoms
Spondylolysis most commonly presents asymptomatic and found incidentally on imaging, however, its most common complaint is lower back pain that's relieved with rest and aggravated by movement[4]. On physical exam, midline tenderness and decreased range of motion of knee extension is also a sign of spondylolysis.
Management
First line therapy for patients with spondylolysis is conservative management such as restricting activity, physical therapy, bracing, and external electrical stimulation.[4] Each of these therapies can be used individually, however, there's greater efficacy and recovery with combination therapy. Conservative treatment's goal is to heal the spinal defect, prevent worsening of the lesion, and provide symptomatic relief for the patient. Typically spinal bracing is used after a failed trial of activity modification and is seen more effective in younger patients, likely due to decreased initiation of bone healing.[4] External electrical stimulation can also be used to repair bone fractures by increasing bone-forming stem cells, inducing mineralization of the bone, forming extracellular matrix, and increasing the expression of osteogenic genes.
Surgical treatment is considered when over 6 months conservative therapy fails to decrease pain, associated symptoms, along with persistent fracture shown on imaging.[4]
References
- ^ Millard, L. (January 1976). "The Scotty dog and his collar". The Journal of the Arkansas Medical Society. 72 (8): 339–40. PMID 129461.
- ^ Morimoto, Masatoshi; Sakai, Toshinori; Goto, Tsuyoshi; Sugiura, Kosuke; Manabe, Hiroaki; Tezuka, Fumitake; Yamashita, Kazuta; Takata, Yoichiro; Chikawa, Takashi; Sairyo, Koichi (29 May 2018). "Is the Scotty Dog Sign Adequate for Diagnosis of Fractures in Pediatric Patients with Lumbar Spondylolysis?". Spine Surgery and Related Research. 3 (1): 49–53. doi:10.22603/ssrr.2017-0099. ISSN 2432-261X. PMC 6690120. PMID 31435551.
- ^ Baig, MN; Byrne, Fergus; Devitt, A; McCabe, J P (2018). "Signs of Nature in Spine Radiology". Cureus. 10 (4) e2456. doi:10.7759/cureus.2456. ISSN 2168-8184. PMC 5991933. PMID 29888160.
- ^ a b c d e Li, Nathan; Amarasinghe, Sam; Boudreaux, Kyle; Fakhre, Waddih; Sherman, William; Kaye, Alan D. (2022). "Spondylolysis". Orthopedic Reviews. 14 (3) 37470. doi:10.52965/001c.37470. ISSN 2035-8164. PMC 9425520. PMID 36045696.