Foramen Magnum Decompression with Cranioplasty for Treatment of Chiari-like Malformation in 126 Cavalier King Charles Spaniel with long-term follow-up (2005-2017)


Although medical management can improve clinical signs in some dogs with CLM, the majority of dogs experience a progression of clinical signs. Some authors report poor results after foramen magnum decompression with a lack of syrinx resolution and as a result do not recommend surgery. The purpose of this study is to report the change in syringomyelia, quality of life scores in a large cohort of CKCS with CLM having FMD and cranioplasty greater than 1 year after surgery.


CKCS MRI-confirmed CLM, and that had FMD with cranioplasty with greater than 1 year follow-up were included. Recorded data included: clinical signs, presence or absence of syringomyelia, general outcome, and length of follow-up. The owners were asked prior to the surgery and at last follow-up to rank their pet’s quality of life.


There were 126 CKCS with at least one year follow-up. At the last MRI the syrinx diameter and length was decreased in 52 dogs (48.6%), static in 36 (33.6%), and increased in 8 (7.5%). Of the 52 dogs with a decrease in syrinx size there were 8 dogs (15.4%) with complete resolution of the syrinx. All eleven dogs (10.3%) that did not have a syrinx preoperatively subsequently did not form a syrinx at the last MRI postoperatively. The mean preoperative QOL score was 2.7 (fair to poor QOL : SD +/- 0.92)). After surgery, 115 (91.3%) dogs had the QOL questionnaires returned. The mean QOL score after surgery improved to 4 (good quality of life: SD +/- 0.89).


Based on our findings, FMD with titanium-mesh cranioplasty can be expected to improve or maintain the quality of life in dogs with CLM in the long term, with approximately half of the dogs not needing any medications and the remaining only needing intermittent medications to maintain an improved quality of life.