Occult Tethered Cord Syndrome: Insights into Clinical and MRI Features, Prognostic Factors, and Treatment Outcomes in 30 Dogs with Confirmed or Presumptive Diagnosis

Javier Espinosa Romero¹Steven De Decker²Koen Santifort^3,4Rodrigo Gutierrez-Quintana⁵Maria Ortega⁶Ane Uriarte⁷Abtin Mojarradi⁸Quinten Van Koulil⁴Despoina Douralidou⁹Irene Espadas¹⁰Miguel Benito Benito¹¹Carlo Anselmi¹²Charlotte Dye¹³Patricia Alvarez¹⁴Juan José Minguez¹⁴Abbe Crawford²Christoforos Posporis^14*

• ¹Neurology and Neurosurgery Department, Independent Vetcare (IVC) Evidensia, Pride Veterinary Referrals, Derby, United Kingdom
• ²Department of Clinical Science and Services, Royal Veterinary College, Hatfield, United Kingdom
• ³Neurology and Neurosurgery Department, Independent Vetcare (IVC) Evidensia, Dierenziekenhuis Arnhem, Arnhem, Netherlands
• ⁴Neurology and Neurosurgery Department, Independent Vetcare (IVC) Evidensia, Dierenziekenhuis Hart van Brabant, Waalwijk, Netherlands
• ⁵Small Animal Hospital, School of Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom
• ⁶Neurology and Neurosurgery Service, Anicura Indautxu Hospital Veterinario, Bilbao, Spain
• ⁷Neurology and Neurosurgery Department, Southfields Veterinary Specialists part of Linnaeus Veterinary Limited, Basildon, United Kingdom
• ⁸Neurology and Neurosurgery Service, AWAKE Animal Hospital, Helsingborg, Skåne, Sweden
• ⁹Neurology and Neurosurgery Department, The Ralph Veterinary Referral Centre, Marlow, United Kingdom
• ¹⁰Neurology and Neurosurgery Service, Unavets Veterios Referral Hospital, Madrid, Spain
• ¹¹Anderson & Moores Veterinary Specialists, Part of Linnaeus Veterinary Limited, Winchester, Hampshire, United Kingdom
• ¹²Imaging Department, Independent Vetcare (IVC) Evidensia, Blaise Veterinary Referral Hospital, Birmingham, United Kingdom
• ¹³Internal Medicine Department, Independent Vetcare (IVC) Evidensia, Pride Veterinary Referrals, Derby, United Kingdom
• ¹⁴Neurology and Neurosurgery Department, Independent Vetcare (IVC) Evidensia, Pride Veterinary Referrals, Derby, United Kingdom., Derby, United Kingdom

Occult tethered cord syndrome (OTCS) is poorly documented in dogs. This retrospective multicenter study evaluated the clinical presentation, MRI findings, treatment outcomes, and prognostic factors in 30 dogs diagnosed with OTCS managed surgically (n = 11) or medically (n = 19). Novel clinical severity scoring and neurological grading systems were developed to assess prognostic utility. The median age at clinical onset was 11 months (range 2-65), with a median duration of clinical signs of 13 months (range 1-60). Pain/dysesthesia in the lumbosacral region/tail/pelvic limbs was the most common presenting complaint (97%), followed by pelvic limb gait abnormalities (70%), behavioral changes (67%), impaired physical activity (63%), and urinary/fecal incontinence (17%). Neurological deficits were present in 90% of dogs. MRI findings showed variability in conus medullaris and dural sac termination, with no physiological translocation detected in available dynamic studies. Electrodiagnostic abnormalities were identified in four of nine tested dogs (44%). Clinical severity scores strongly predicted response to medical treatment, with responders having significantly lower scores than non-responders (3.25 ± 2.09 vs. 7.78 ± 3.15, p < 0.001). Higher neurological grades (p = 0.006), presence of behavioral abnormalities (p = 0.045), and worsening clinical evolution prior to referral (p = 0.009) were also associated with poor medical therapy outcomes. Surgical intervention was significantly associated with full recovery (p = 0.015) and discontinuation of medical treatment (p = 0.023) at last follow-up (median: 9 months, range: 2-108). Three surgically treated dogs experienced partial relapse within six months, with two undergoing reintervention and improving postoperatively. This study highlights the clinical and MRI characteristics of canine OTCS, introduces novel prognostic factors, and supports surgical detethering as a key intervention for optimizing outcomes. Larger prospective studies are needed to validate these findings, refine the proposed scoring systems, and establish evidence-based guidelines for managing canine OTCS.