For Veterinarians

How the Canine Chiari Institute Collaborates with Veterinarians

At the Canine Chiari Institute at LIVS, our team of board-certified veterinary neurologists conduct ongoing studies, research, and pilot breakthrough treatments for pets affected with Chiari-like Malformation and Syringomyelia. Partnering with a LIVS specialist in the care of these patients allows us, together, to make an accurate diagnosis and develop an optimal treatment plan.

More on Chiari-like Malformation

Chiari-like Malformation (CLM), formerly known as Caudal Occipital Malformation Syndrome (COMS), is a condition in dogs, which the rearmost part of the brain, the cerebellum, descends out of the skull through the opening at its base, called the foramen magnum, crowding the spinal cord.

The exact cause is not completely understood. However, it is believed that due to an abnormal skull shape or reduced skull size, part of the cerebellum is forced through the foramen magnum, altering the normal cerebral spinal fluid (CSF) flow in that region. Changes in CSF dynamics and pressure gradients caused by this syndrome (Syringomyelia) may result in abnormal accumulations of fluid within the substance of the cervical spinal cord called “syrinxes.” Recent evidence supports the concept that CLM represents an overall mismatch between intracranial volume and the tissue occupying that volume – the skull is too small for the brain and vice versa) rather than a disorder confined to the back of the brain skull.

Chiari-like Malformation and Syringomyelia (the presence of one or more syrinxes) have high heritability. Although it appears that CLM affects Cavalier Kings Charles Spaniels (CKCS) predominately, this may be misleading since active breeder support has resulted in intensive scrutiny of the CKCS breed, well beyond the assessment of other small breed dogs. With increased awareness in the veterinary community in recent years, almost 40% of dogs operated on at The Canine Chiari Institute at Long Island Veterinary Specialists (LIVS) for CLM are not CKCS dogs.

Clinical signs include:

  • Persistent back of the head-scratching 
  • Pain in the neck 
  • Loss of balance 
  • Difficulty walking 
  • Seizures
  • Head tilt

Diagnosing Chiari-like Malformation

At The Canine Chiari Institute, we are equipped with one of the only 3.0 Tesla MRI machines in private veterinary practice. This allows for exceptional quality imaging studies including better resolution, faster scanning, less anesthesia time, and we can perform CSF flow studies with each patient.

High-Field Magnets

The magnet is the biggest, most expensive, and influential component of an MRI system. Recent years have been marked by a dramatic movement in clinical imaging from 0.5 T to 3.0 T imaging systems. The advantage of high field magnets clinically translates into improved resolution and shorter acquisition time.

Parallel Imaging Techniques

Parallel imaging techniques permit the rapid acquisition of whole-body images with a high spatial resolution providing diagnostic detail in all areas of the image. Software developments also deserve brief mention. Most systems now have specially designed interfaces that minimize the operator’s technical intervention and instead rely on the automated selection of imaging protocols based on clinically driven menus. Automation of the examination procedure allows high-quality examinations to be performed with consistency and accuracy.

Treatment Options Available at LIVS

CLM is a serious condition and treatment is dependent on the severity, age, and overall health of the animal.

Young dogs with mild changes should still be considered surgical candidates to minimize the progression of the disease as the dog ages. Severe cases of CLM/SM, regardless of age, are still surgical candidates as a lot of dogs do have some relief of clinical signs as they heal. Many dogs may still require management post-operatively with medication, but the variety and dosages can often be reduced with surgical correction. Dogs that have been managed with medication initially and continue to have disease progression may still benefit from surgical intervention.

One of the most common and devastating aspects of CLM/SM in dogs is pain. In addition, the scratching activity characteristic of the disorder is suspected to be a sensory disturbance called paranesthesia. Most dogs with CLM/SM with clinical signs of disease exhibit varying degrees of neck pain.

It has become apparent that many patients, however, have pain throughout the length of their spine. When these dogs have MR imaging of their thoracic and lumbar spines performed, in addition to their neck region, syrinx cavities are usually found in all of the imaged locations.

There are a number of medical therapies that seem to help CLM/SM dogs with both pain management and scratching activity. Still, there are no controlled clinical trials published yet to measure the efficacy/inefficacy of these treatments objectively. Therefore, there are a lot of opinions regarding which drugs or drug combinations are helpful in this disorder. The three main categories of medical therapy for CLM/MS include:

  • Analgesic (pain-relieving) drugs
  • Medicines that decrease CSF production
  • Corticosteroid therapy (which has multiple effects)

Ongoing Studies

Grossbard BP, Loughin CA, Marino DJ
Thermographic imaging is a non-invasive method used to screen animals for multiple medical problems. This study documents the use of thermal imaging to screen small breed dogs for possible herniated disc disease. Dogs with confirmed herniation based on MRI results are compared to dogs that have no evidence of a herniated disc. We also look at the usefulness of thermography to predict the site of herniation.

Grossbard BP, Loughin CA, Marino DJ
Primary secretory otitis media, also known as PSOM, is a disease of the inner ear. A mucous plug collects behind the ear drum, and can cause pain and scratching. Reported treatments have had variable success, and the mucous plug tends to recur. This study explores initial treatment with myringotomy followed by clavamox for 2 weeks.

Govier S, Loughin CA, Marino DJ
Primary secretory otitis media, also known as PSOM, is a disease of the inner ear. A mucous plug collects behind the ear drum, and can cause pain and scratching. Diagnosis has primarily depended on visualization of a pink swollen ear drum on examination of the ear canal. This type of examination can lead to missed diagnosis of PSOM since it is difficult to visualize this change. Recent studies have found that PSOM can easily be seen on a MRI, but MRIs are expensive and not widely available. This study looks at the accuracy of CT to diagnose PSOM.

Lugones M, Loughin CA, Marino DJ
Cavalier King Charles Spaniels constitute a breed that has a predisposition for PSOM and CLM, but “can these dogs have both diseases at the same time?” This study looks at a population of dogs being evaluated for CLM, and determines how prevalent PSOM is in this group of dogs.

Marino DJ, Loughin CA, Dewey CW, Marino LJ, Sackman J, Lesser M, Ackerman M
Evaluation of MRIs for CLM have mainly been based on the doctor’s opinion on how compressed and herniated the cerebellum may be. This kind of evaluation leads to considerable variability, resulting in disagreement among doctors. In order to make MRI evaluations more consistent, measurements made in the region of the skull and vertebrae of the neck have been developed. This paper reports the consistency of these new measurements.

Loughin CA, Marino DJ, Dewey CW
Syringomyelia, also called SM or syrinx, has been documented as a secondary occurrence to CLM. Based on multiple theories and the results of research in humans, we suspect that the syrinx will slowly regress after decompressive surgery. This paper looks at a group of dogs diagnosed with CLM and SM, and follows them for one year after surgery to see what happens to the length and volume of the syrinx over time.

Dewey CW, Loughin CA, Marino DJ
MRI studies of dogs thought to have CLM have included mainly the skull and neck, but does the syrinx exists further down the spinal cord? This study looks at a group of dogs with CLM and SM to see how far the syrinx can extend.

Loughin CA, Marino DJ, Peters R
Dural biopsies performed in humans with chiari-like malformation have shown thickening of the dura mater. Some of this thickening has even been described as “bone-like”. Do dogs with CLM exhibit the same changes of the dura mater at the site of compression? This paper evaluates the biopsy reports of a group of dogs that have undergone surgery for CLM to determine if the dura develops “bone-like” qualities.
Last Updated ( Wednesday, 13 October 2010 12:41 )

Published Papers

Dewey CW, Budsberg SC, Oliver JE.  Principles of head trauma management in dogs and cats, Part I.  Compend Contin Educ Pract Vet 14(2): 199-207; Emergency Medicine and Critical Care in Practice,1992 221-227.

Marino DJ, Jaggy A. Nocardiosis: A literature review with selected case reports in two dogs. J Vet Intern Med1993; 7:4-11.

Marino DJ, Macdonald JM, Matthiesen DT, Salmeri KR, Patnaik AK. Results of surgery and long-term follow-up in dogs with ceruminous gland adenocarcinoma. J Am Anim Hosp Assoc 1993; 29:560-563.

Dewey CW, Downs MO, Aron DN, Mahaffey EA.  Acute traumatic intracranial hemorrhage in dogs and cats: A retrospective evaluation of 23 cases.  VCOT, 1993;6:153-159.

Dewey CW, Downs MO, Crowe DT.  Management of a dog with an acute traumatic subdural hematoma. J Am Anim Hosp Assoc, 1993; 29: 551-551.

Dewey CW, Budsberg SC, Oliver JE.  Principles of head trauma management in dogs and cats, Part II.  Compend Contin Educ Pract Vet, 1993; 15(2): 177-193.

Marino DJ, Macdonald JM, Matthiesen DT, Patnaik AK. Results of surgery in cats with ceruminous gland adenocarcinoma. J Am Anim Hosp Assoc1994; 230:54-57

Marino DJ, Matthiesen DT, Fox PR, Lesser MB, Stamoulis ME. Ventricular arrhythmias in dogs undergoing splenectomy: A prospective study. Vet Surg 1994; 23:101-106

Dewey CW, Aron DN, Foutz TL, Marks MA, Budsberg SC.  Static strength evaluation of two modified unilateral external skeletal fixators.  J Small Anim Pract, 1994; 35: 211-216.

Marino DJ, Stefanacci J, Matthiesen DT, Morhoff S.  Evaluation of dogs with digit masses: 117 cases (1981-1991). J Am Vet Med Assoc1995; 207: 726-728.

Dewey CW, Shelton GD, Bailey CS, Willard MD, Podell M, Collins RC.  Neuromuscular dysfunction in five dogs with acquired myasthenia gravis and presumptive hypothyroidism. Prog Vet Neurol, 1995;6(4):117-123.

Duval J, Dewey CW, Roberts R, Aron DN.  Spinal cord swelling as a myelographic indicator of prognosis: a retrospective study in dogs with intervertebral disc disease and loss of deep pain perception.  Vet Surg, 1996;25: 6-12.

Culbert LA, Marino DJ, Baule RM. Complications associated with high-doseprednisolone sodium succinate therapy in dogs with Acute Neurologic Injury.  J Am Anim Hosp Assoc1997; 34: 129-134

Dewey CW.  Acquired myasthenia gravis in dogs, Part I.  Compend Contin Educ Pract Vet, 1997;19(12): 1340-1354.

Dewey CW, Bailey CS, Haskins SC, Kass PH, Crowe DT.  Evaluation of an epidural intracranial pressure monitoring system in cats.  J Vet Emerg Crit Care, 1997; 7(1): 20-33.

Marino DJ, Spleen in Kirk’s Current Veterinary Therapy XIV.ed Bonagura 1998

Dewey CW.  Advances in small animal neurology and neurosurgery (editorial).  Compend Contin Educ Pract Vet,1998; 20(8): 892-895.

Coates JR, Dewey CW.  Cervical spinal hyperesthesia as a clinical sign of intracranial disease.  Compend Contin Educ Pract Vet, 1998;20(9): 1025-1037.

Jerram RM, Dewey CW.  Suspected spinal epidural empyema and associated vertebral osteomyelitis (physitis) in a dog.  J Vet Emerg Crit Care,1998; 8(3): 215-220.

Dewey CW, Kortz GD, Bailey CS.  Spinal epidural empyema in two dogs.  J Am Anim Hosp Assoc, 1998;34: 305-308.

Dewey CW.  Acquired myasthenia gravis in dogs, Part II.  Compend Contin Educ Pract Vet, 1998;20(1): 47-59.

Dewey CW, Coates JR, Boothe DM.  Nothing is simple about epilepsy (editorial). Vet Forum, 1998;September.

Jerram RM, Dewey CW.  Acute thoracolumbar disk extrusion in dogs, Part II.  Compend Contin Educ Pract Vet1999;21 (11): 1037-1047

Jerram RM, Dewey CW.  Acute thoracolumbar disk extrusion in dogs, Part I.  Compend Contin Educ Pract Vet1999;21 (10): 922-931.

Dewey CW, Coates JR, Ducoté JM, Meeks JC, Fradkin JM.  Azathioprine therapy for acquired myasthenia gravis in five dogs. J Am Anim Hosp Assoc1999;35: 396-402.

Franks J, Dewey CW, Walker MA, Storts R.  Computed tomographic findings of ceroid lipofuscinosis in a dog.  J Am Anim Hosp Assoc1999;35;430-435.

Ducoté JM, Coates JR, Dewey CW, Kennis RA.  Case report: Suspected hypersensitivity to phenobarbital in a cat.  J Feline Med and Surg1999;1:123-126.

Ducoté JM, Johnson KE, Dewey CW, Walker MA, Coates JR, Berridge B.  Computed tomography of necrotizing meningoencephalitis in three Yorkshire Terriers.  Vet Rad Ultrasound1999;40(6):617-621.

Ducoté JM, Dewey CW, Coates JR. Clinical forms of acquired myasthenia gravis in cats.  Compend Contin Educ Pract Vet1999;21(5): 440-448.

Dewey CW, Boothe DM, Rinn KL, Coates JR, Burkholder WJ.  Treatment of a myasthenic dog using mycophenolate mofetil.  J Vet Emerg Crit Care 2000; 10(3):  177-187.

Dewey CW, Coates JR, Bahr A, Walker MA, Ducoté JM.  How I treat: Primary brain tumors in dogs and cats.  Compend Contin Educ Pract Vet2000;22 (8):  756-762.

Spangler EA, Dewey CW.  Meningoencephalitis secondary to bacterial otitis media-interna in a dog.  J Am Anim Hosp Assoc2000; 36:239-243.

Davis MJ, Dewey CW, Walker MA, et al.  Contrast radiographic findings in canine bacterial discospondylitis: A multicenter, retrospective study of 27 cases.  J Am Anim Hosp Assoc2000;36:81-85

Dewey CW. External hydrocephalus in a dog with suspected bacterial meningoencephalitis. J Am Anim Hosp Assoc 2000;38: 563-567

Puccio M, Marino DJ. Clinical evaluation and long-term follow-up of dogs with coronoidectomy for elbow incongruity. J AM Anim Hosp Assoc2003; 39:473-478.

Dewey CW, Coates JR, Ducote’ JM, Steffanacci JD, Walker MA, Marino DJ. External hydrocephalus in two cats. J Am Anim Hosp Assoc2003; 39: 567-572.

Dewey CW. A feline challenge. NAVC Clinician’s Brief2003; June: 9-10.

Dewey CW.  Acute onset of neck pain in a dog. NAVC Clinician’s Brief2003; July: 7-8.

Panarello GL, Dewey CW, Barone G, Stefanacci JD. Magnetic resonance imaging of two suspected cases of global brain ischemia. J Vet Emerg Crit Care 2004;14 (4): 269-277.

Dewey CW, Berg JM, Stefanacci JD, Barone G, Marino DJ. Caudal occipital malformation syndrome in dogs.  Compend Contin Educ Pract Vet 2004; 26(11): 886-896.

Dewey CW, Guiliano R, Boothe DM, et al.  Zonisamide therapy for refractory idiopathic epilepsy in dogs. J Am Anim Hosp Assoc2004; 40: 285-291.

Cherrone K, Dewey CW, Coates JR, et al. Hansen Type I cervical disk extrusions in large-breed non-chondrodystrophic dogs: A comparative retrospective study of 46 cases (1998-2002). J Am Anim Hosp Assoc2004; 40: 316-320.

Dewey CW, Barone G, Smith K, Kortz GD. Alternative anticonvulsant drugs for dogs with seizure disordersVet Medicine 2004;99 (9): 786-793.

Loughin CA, Marino DJ, Dewey CW, Gamble DA. Ectopic splenic tissue in the liver of a dog.   Vet MedJan 2005; Vol. 100, No. 1.

Pettigrew R, Stefanacci JD, Loughin CA, Marino DJ. What’s your diagnosis? J Am Vet Med Assoc2005; 226: 1485-1486.

Dewey CW, Berg JM, Barone G, et al. Foramen magnum decompression for treatment of caudal  occipital malformation syndrome in dogs. J Am Vet Med Assoc2005; 227 (8):  1270-1275.

Pfohl JC, Dewey CW. Intracranial Toxoplasma gondii 2005;granuloma in a cat. Feline Med Surg 7 (6): 369-374.

Loughin CA, Dewey CW, Ringwood PB, et al. Effect of durotomy on functional outcome of dogs with type I thoracolumbar disc extrusion and absent deep pain perception. Vet Comp Orthop Traumatol 2005; 18: 141-146.

Cook LB, Coates JR, Dewey CW, et al. Vascular encephalopathy associated with bacterial endocarditis in four dogs.  J Am Anim Hosp Assoc 2005; 41: 252-258.

Loughin CA, Marino DJ, Dewey CW, Gamble DA. A challenging case: a lethargic and depressed dog with a long history of problems.  Vet Medicine  2005;100 (1): 40-44.

Hillock SM, Dewey CW, Stefanacci JD, Fondacaro JV. Vascular encephalopathies in dogs: incidence, risk factors, pathophysiology, and clinical signs. Compend Contin Educ Pract Vet2006;28 (3): 196-207.

Hillock SM, Dewey CW, Stefanacci JD, Fondacaro JV. Vascular encephalopathies in dogs: diagnosis, treatment, and prognosis. Compend Contin Educ Pract Vet2006; 28 (3): 208-217.

Coates JR, Axlund TW, Dewey CW, Smith J. Hydrocephalus in dogs and cats. Compend Contin Educ Pract Vet 2006;28 (2): 136-146

C.A. Loughin, Marino DJ. Screening of Cavalier King Charles Spaniels for Chiari-like malformation, British Journal of Neurosurgery Oct, 2007, issue 21.5; 451

Marino DJ. Foramen magnum decompression with cranioplasty for the treatment of Chiari-like malformation in dogs,British Journal of Neurosurgery Oct, 2007, issue 21.5; 469

Lombardi R, Marino DJ. Long Term Evaluation of Dogs Perianal Fistula Disease Treated with Surgical excision and Beef avoidance diet. J AM Anim Hosp Assoc2009; 44:302-307.

Dewey CW, Bailey KS, Marino DJ, Barone G, Bolognese P, Milhorat TH, Poppe DJ. Foramen magnum decompression with cranioplasty for the treatment of caudal occipital malformation syndrome in dogs. Vet Surg 2007 Jul;36(5): 406-15

Loughin CA, Marino DJ. Evaluation of Thermographic Imaging of the Limbs of Healthy Dogs. Am J Vet Res 2007, Oct;68(10): 1064-9

Scrivani PV, Thompson MS, Winegardner KR, Dewey CW, Scarlett JM. Association between frontal sinus size and syringohydromyelia in small-breed dogs: 62 cases (2004-2006). Am J Vet Res.2007

Loughin CA,  Marino DJ. Delayed Primary Surgical Treatment in a Dog with a Persistent Right Aortic Arch.  J AM Anim Hosp Assoc2008; 44:258-261

Marino, DJ. Advances in Neuro Imaging: Magnetic Resonance Imaging, Computed Tomography and Thermography, American College of Veterinary Surgeons Symposium proceeding; October 2008

Marino, DJ. Chiari Like Malformation and Syringomyelia in Dogs, American College of Veterinary Surgeons Symposium proceeding; October 2008

House, M., Marino, DJ., Puccio, M., Stefanacci, JD. The Effect of CT Elbow Positioning on Diagnosis of Elbow Incongruity; Vet Surg 2009 Jul;38(2): 154-160

Marino, DJ. Chiari Like Malformation in Dogs, American College of Veterinary Surgeons Symposium proceeding; October 2009

Marino, DJ. Syringomyelia in Dogs, American College of Veterinary Surgeons Symposium proceeding; October 2009

Infuernuso, T., Loughin, C., Marino, DJ. Thermographic imaging of dogs with Cranial Cruciate Deficient Stifles; Vet Surg ,2010; June

Marino, DJ. Advanced Imaging of the Canine Stifle; Invited editor Vet Surg, 2010, April

Refer a Case

If a patient is exhibiting symptoms related to CLM/MS, refer them to the Canine Chiari Institute at LIVS for evaluation.

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