Spinal Cord DiseasesPart 2

Casey P. Neary, DVM, DACVIM (Neurology)Neurology/Neurosurgery4/9/17

• V – Vascular • I – Infectious / Inflammatory• T – Trauma• A – Anomalous• M – Metabolic

• I – Idiopathic

• N – Neoplasia• D – Degenerative

Anomalous• Vertebral malformations• Cysts / Diverticula• Cervical spondylomyelopathy (Wobbler)

Vertebral Malformations• Variety of neurologic symptoms Myelopathy Radiculopathy

• However… VAST majority are incidental findings / clinically

insignificant

Vertebral Malformations• Generally breed-associated• Exception Mucolipidosis

• Bulldog overrepresented Also…

Vertebral Malformations• Many different classification systems Stage of development

• Embryonic– Hemivertebrae– Wedge vertebrae– Butterfly vertebrae

• Fetal– Block vertebrae– Articular process hypoplasia

Vertebral Malformations

http://rad.washington.edu/about-us/academic-sections/musculoskeletal-radiology/teaching-materials/online-musculoskeletal-radiology-book/scoliosis/

Articular Process Hypoplasia• Hypoplasia or aplasia• Pugs

Articular Process Hypoplasia• “Pug Myelopathy”• Hypoplasia / aplasia of

caudal articular facets Thoracolumbar region

• Leads to chronic instability and secondary fibrous band Constrictive

myelopathy(J Am Vet Med Assoc 2013;242:223–229)

Vertebral Malformations• Diagnostics Radiography

• Most are easily identified

MRI• Cross-sectional analysis• Spinal cord compression• Other abnormalities

– Disc– Cyst / diverticula

Vertebral Malformations• Treatment Dependent on…

• Significance• Type• Number• Severity• Stability

Vertebral Malformations• Treatment Medical management

• Strict confinement• NSAIDs vs. steroids• Analgesic therapy

Surgery• Rarely performed…

Vertebral Malformations• Surgical Management More common to address secondary disease

• Block vertebrae– Disc

• Hemivertebrae– Cyst / diverticula

Vertebral Malformations• Surgical Management Simple

• Dorsal laminectomy• Hemilaminectomy

Complex• Requiring stabilization

“Chewy”

• 4 month old Chihuahua mix

• Weak / wobbly in PL since adoption

“Chewy”

“Chewy” MRI

“Chewy” CT

T6-7 T13

“Chewy”

Chewy’s 3D model

“Chewy”

Post-op radiographs

Right lateral

VD

Vertebral Malformations

• The 4 Questions Onset?

• Chronic– Months to years

Progression?• Slowly progressive

Symmetry?• Usually symmetric

Painful?• No

Spinal Arachnoid Diverticula• Focal dilations of the subarachnoid space• Formerly known as cysts• More common in brain

https://www.researchgate.net/figure/262810151_fig2_Transverse-plane-CT-myelogram-CT-image-showing-the-focal-accumulation-of-contrast-medium

Spinal Arachnoid Diverticula• Compressive myelopathy• Most common symptom Proprioceptive ataxia

• Two groups of dogs Cervical

• Large breed dogs– Rottweiler

Thoracolumbar***• Frenchies and Pugs

Spinal Arachnoid Diverticula• Corkscrew tail breeds• Very common to have concurrent disease

adjacent to SAD

Spinal Arachnoid Diverticula• Diagnostics CT / myelogram? MRI!!

• Diagnosis– FLAIR

• Also…– Cord changes

» Edema, gliosis

– Concurrent diseases

“Francisco”

“Francisco”

Spinal Arachnoid Diverticula• Treatment Medical management

• Prednisone (low dose)• Omeprazole• +/- furosemide, acetazolamide

Surgery• Laminectomy• Durotomy• Marsupialization

Spinal Arachnoid Diverticula• Prognosis Medical therapy

• Unknown – no studies to date• “Guarded”

Surgery• ~63% - improved• ~37% - worsened

Spinal Arachnoid Diverticula

• The 4 Questions Onset?

• Chronic– Months to years

Progression?• Slowly progressive

Symmetry?• Usually symmetric

Painful?• No

Cervical Spondylomyelopathy• “Wobbler syndrome”• Condition of large and giant breed dogs• Static or dynamic compression Spinal cord Nerve roots pain and spinal cord dysfunction

• Causes Genetic, congenital, conformational, nutritional

Cervical Spondylomyelopathy• Breeds Great Dane, Doberman,

Basset

• Pathogenesis Multifactorial Canal stenosis from disc,

ligament, joint capsule, bone, vertebral instability, among others…

Cervical Spondylomyelopathy• Two forms Doberman

• Older dogs (6.8 years)• Caudal cervical• Disc-associated

Great Dane• Younger dogs (3.8 years)• Cranial-to-mid cervical• Osseous-associated

Cervical Spondylomyelopathy• Basset hound Unique form of disease JVIM, 2012, De Decker et. Al Dorsal lamina & spinous

process hypertrophy leads to ligamentum

flavum hypertrophy

Basset Spondylomyelopathy

Basset Spondylomyelopathy

“George” – 5 mo Basset Hound

Cervical Spondylomyelopathy• Diagnostics CT / Myelography MRI

• Diagnosis• Dynamic vs. static• Cord changes***

“Fitz” – 2 yo MN Great Dane

Cervical Spondylomyelopathy• Treatment Medical

• Prednisone!• Gabapentin• Controlled exercise

Surgery• Dependent on type, extent, severity• Ventral slot, dorsal laminectomy• +/- stabilization• Disc replacement??

http://dogquality.com/blogs/senior-dog-blog/18091711-cervical-disc-replacement-in-dogs

Cervical Spondylomyelopathy• The 4 Questions Onset?

• Chronic, Acute-on-Chronic

Progression?• Progressive

Symmetry?• Usually symmetric

Painful?• Osseous-associated

– 50/50

• Disc-associated– Yes!

• V – Vascular • I – Infectious / Inflammatory• T – Trauma• A – Anomalous• M – Metabolic

• I – Idiopathic

• N – Neoplasia• D – Degenerative

Neoplasia• Primary Arising from the spinal cord or meninges

• Secondary Adjacent

Primary SC Neoplasia

• Can be broken into 2 categories Intramedullary Intradural, extramedullary

http://sevneurology.com/lupa-spinal-tumor/

Intramedullary SC Neoplasia

• Uncommon ~15% of spinal cord tumors

• 2/3 are primary Neuroepithelial

• Glial cells• Ependyma

• 1/3 are secondary Metastatic

Intramedullary SC Neoplasia

• Primary tumors More common…

• Young dogs• Cervical spinal cord

• Secondary More common…

• Older dogs• Thoracolumbar spinal cord

Intramedullary SC Neoplasia

• Primary tumors Mean age is 5.9 years Most common is ependymoma

• Followed by– Astrocytoma– Oligodendroglioma

Intramedullary SC Neoplasia

• Secondary / metastatic tumors Mean age is 10.8 years Most common…

• Hemangiosarcoma• TCC• Prostatic carcinoma• LSA?

Intramedullary Neoplasia

• The 4 Questions Onset?

• Acute-to-chronic

Progression?• Progressive

Symmetry?• Often symmetric

Painful?• Nope!!

Intradural, Extramedullary

http://www.neuroradiologycases.com/2011/08/nerve-sheath-tumour.html

Intradural, Extramedullary

• Meningioma Most common in dogs Arises from arachnoid granulation of meninges

• Locations– Cervical most common

Grades• I-III

Types• Numerous!!

Transitional Meningioma

Sturges et. al. J Vet Intern Med 2008;22:586–595

Meningothelial Meningioma

Sturges et. al. J Vet Intern Med 2008;22:586–595

Angiomatous Meningioma

Sturges et. al. J Vet Intern Med 2008;22:586–595

Microcystic Meningioma

Sturges et. al. J Vet Intern Med 2008;22:586–595

Meningioma

• Treatment Palliative care Oral chemotherapy

• Hydroxyurea

Surgery alone• 1410-1440 days (Levy et. al 1997)• 19 months (Petersen et. al 2008)

Surgery + Radiation• ??? Likely longer…

Intradural, Extramedullary

• Nerve sheath tumors Types

• Schwannomas• Neurofibromas• Neurofibrosarcomas

Nerve Sheath Tumors

Nerve Sheath Tumors

• Treatment Palliative care Radiation

• 371 ± 30 days

Surgery alone• 6-9 months

Surgery + Radiation• ??? Likely longer…

Nephroblastoma

• “Thoracolumbar tumor of young dogs”• Embryonal tumors of the kidneys• Neoplastic transformation of blastemal cells Retroperitoneal primary renal tumor Within dura spinal tumor

• T10-L3• GSD, Golden retrievers

Nephroblastoma

• Age at onset 5-48 months

• Median 14 months

• Progressive symptoms T3-L3 Paraparesis / ataxia to

paraplegia

Nephroblastoma

Nephroblastoma

• Treatment Medical management Surgery

• Dorsal / hemilaminectomy• Durotomy

• Prognosis Poor

• MST 30 days in all dogs• Surgical resection

– MST 70.5 days

Extradural Tumors

• Vertebral tumors Osteosarcoma Fibrosarcoma Chondrosarcoma Multiple myeloma Lymphoma Metastatic…

Extradural Tumors

• Other sites Soft tissue Abdominal Retroperitoneal Esophageal

ID-EM and Extradural Tumors

• The 4 Questions Onset?

• Acute-to-chronic

Progression?• Progressive

Symmetry?• ED Symmetric • ID-EM Asymmetric

Painful?• Most are…

– Meninges, nerve, muscle

• V – Vascular • I – Infectious / Inflammatory• T – Trauma• A – Anomalous• M – Metabolic

• I – Idiopathic

• N – Neoplasia• D – Degenerative

Degenerative• Intervertebral disc disease (IVDD)• Degenerative myelopathy (DM)

Max,7 yr, MN Dachshund

Max – The Situation

• 2 days ago – sudden onset not walking, painful

• 1 day ago – pcDVM - paralyzed and no deep pain

• Your exam – quite the same

• Diagnosis ? Prognosis?

Max – The truth

• Came in through ER (~8PM)• Plegic, DPP (NEGATIVE)

• Advised to wait til AM to have MRI

• 8AM• Exam unchanged.

MRI

Outcome

• Left hemilaminectomy at T12-T13 with removal of massive amount of paste-like disc

• Grossly normal spinal cord

• Weakly ambulatory at discharge 2 ½ days later

Ito D, et. al. Prognostic value of magnetic resonance imaging in dogs with paraplegia caused by thoracolumbar intervertebral disc extrusion: 77 cases (2000-2003). J Am Vet Med Assoc. 2005; 227: 1454-60

Deep Pain Negative & Hemilaminectomy

T2 Signal Changes

Number Recovered

Success Rate

None noted 13/13 100%

< 3x length L2 4/6 66%

> 3 x length L2 1/10 10%

Totals 18/29 62%

Deep Pain Positive & Hemilaminectomy

T2 Signal Changes

Number Recovered

SuccessRate

None noted 31/31 100%

< 3x length L2 11/12 92%

> 3 x length L2 2/5 40%

Totals 44/48 92%

• MRI findings best predictor of outcome in paraplegic dogs

• Generally success rates are 92% and 62%, in DPP+, DPP – respectively

MRI as predictor of outcome

• Allows for evaluation of SC health• Without MRI Prognoses range from 10-100%

• “50/50”

• MRI allows for… Establishment of diagnosis Accurate prognosis!

Why wait??

• Our beliefs Diagnostic and prognostic value of MRI is worth the wait CT / myelogram?? Little harm in waiting

• 2 components of injury caused by disc rupture 1) Concussive internal injury sustained at moment

of impact• Most important / fate is sealed at time of rupture

2) Ongoing compression

Why MRI for Type I Disc Disease?

• MRI consistently superior to myelography for determining lesion localization and lateralization (Bos)

• Correlation between MRI and surgical findings is 100% for lesion localization and lateralization (Besalti, Naude )

• Superior to deep pain status in determining outcome in paraplegic dogs

Besalti, O, et. al. Can Vt J. 2005: 46: 814-20.Bos AS. University of Guelph. 2008: 113-49Naude SH, JAVMA 2008; 232: 702-8.

No harm in waiting…

• JAVMA 2016 Jeffery et. al

• Goals of study Identify factors associated with recovery of

locomotion

• 78 dogs that underwent spinal surgery for IVDD Iowa State, TAMU, UK

JAVMA 2016 cont.

• Results No evidence that prognosis for recovery of

ambulation was related to time from onset of non-ambulatory state or loss of DPP

• Conclusion “Immediacy of surgical treatment had no

apparent association with outcome” Rather, the prognosis strongly influenced by

nature of initiating injury

Further Evidence…

• JAVMA 2003 Olby et. al Study on spinal trauma

• Including IVDD, HBC, etc.

Outcome was not associated with duration of paraplegia Additionally, 0% of DPP(-) dogs recovered that

had suffered “trauma” (fracture, subluxation, etc.)

Further Evidence…

• JSAP 1999 Scott, McKee No statistical significance to show duration of loss

of DPP impacted the prognosis

• JAVMA 2005 Ito et. al Duration of clinical signs

• Not associated with outcome

However….

• We do still recommend prompt establishment of diagnosis and prognosis

• Surgical intervention (if indicated) Sooner rather than later.

Type I Disc Disease

Intervertebral Disc Degeneration

Brisson, B. Vet Clin Small Anim. 2010; 40:829-858.

Type I - Breeds

• Overall prevalence = 2% (Bray, 1998)• Dachshunds (20%), Pekingese, beagle, cocker

Type I – Age

• Chondrodystrophic: 3-7 years• Non-chondrodystrophic: 6-8 years

- Large breed dogs: mixed, German Shepherd, Labrador, Rottweiler, Dalmatian, Doberman

Surgery vs. Medical Management?

• In general with an isolated disc rupture… Surgery

• Prognosis with surgery is >95%• Quicker recovery• Low recurrence with fenestration

– ~8%

Medical management• Fair prognosis• Recurrence rates

– 30-50%

Medical

• What are we trying to accomplish?

• Rest is key!!!! All medically managed cases

will be more likely to fail if not rested.

• So, rest (not medication) is more important!

NSAIDS > Steroids

• NSAID therapy associated with higher satisfaction (better pain control, fewer side effects) via questionnaire (Levine)

• Administration of steroid is associated with higher rate of GI and urinary complications causing increased hospital stay

• NSAIDS lower recurrence rate than prednisone (Mann)• Steroids impair healing (annulus)

Levine JM, et. al. Vet Surg.2007; 36: 482-91.Mann FA, et. al. J Emer Crit Care. 2007; 17: 53-60.

Medical

• My preference NSAID

• Meloxicam, Carprofen

Gabapentin Tramadol Muscle relaxer

• Other Urinary status

Surgery

• Best if done sooner…• If delayed >2 weeks Prognosis could worsen Why?

• Disc material analogy• If delayed…

– Adhered to dura, vessels– More challenging– More dangerous

Type 1 Disc Summary

• Not as time sensitive as once thought. Down ≠ Down n’ Out

• Recommend referral in all dogs with suspected disc disease Establish diagnosis and PROGNOSIS

• Educate owners of risks associated with medical management Recurrence Surgery for chronic discs

Type 1 Disc

• The 4 Questions Onset?

• Peracute-to-acute

Progression?• Progressive

Symmetry?• Often subtly asymmetric

Painful?• Yes!

Disc Disease – Type 2

• Signalment Large breed dogs 6-8 years GSD, Lab, Golden

Disease Physiology

• Disc degeneration• Fibrous form of

metaplasia nucleus pulposus

replaced with fibrocartilage

weakening of the dorsal annulus

protrusion, bulging of annulus

Type 2 - Signs / Progression • Lumbosacral (L7-S1) disc protrusions

• Slow to rise / sit• Paraparesis• Poor reflexes• Incontinence• Tail abnormalities• Pain

• Low cervical disc protrusions (Disc associated Wobbler’s syndrome or DAWS)• Tetraparesis• Tetra-ataxia• Pain

Surgery and L7-S1 Type II Disc

• Dorsal laminectomy with fenestration• 131 cases, GSD, painful / reluctant to jump, rise, climb

stairs, 93% improved, 17% recurrence rate (Danielsson)• 69 cases, various grades, 78% good outcome (De Risio)

- Urinary or fecal incontinence has a worse prognosis - Chronic urinary incontinence predicts poor outcome

• DO NOT confuse with orthopedic disease and wait to address the problem until incontinent

Danielsson F, et al Vet Surg 1999;28(2):91-98.De Risio L, et al. JAVMA 2001;219(5):624-628.

Type 2 Disc

• The 4 Questions Onset?

• Chronic

Progression?• Progressive

Symmetry?• Usually symmetric

Painful?• Yes

IVDD in Cats??

• Yes!• Far less common• Older• Lumbar disc disease L4-L5

• Type 1 > Type 2• Outcome similar to dogs

“Amy” – 11 yo FS Balinese

Degenerative Myelopathy

• First described in 1973 Non-specific degeneration

• Most dogs in initial reports were GSD

• However, common in several other breeds Overall prevalence of

0.19%

Degenerative Myelopathy

• Cause Mutation in superoxide dismutase 1 gene

• SOD1• Antioxidant / free radical scavenger

Amyotrophic lateral sclerosis• ALS / Lou Gehrig’s disease• Differences

– Neuron vs. axon

Degenerative Myelopathy

• Progressive disease in older dogs 8-14 years

• Large breed dogs GSD, Boxer, CBR Mean age of 9 yo

• PWC Mean age of 11 yo.

Degenerative Myelopathy

• Clinical Progression Spectrum of symptoms

• Proprioceptive ataxia, paraparesis

– T3-L3 spinal cord segments

• Progress to non-ambulatory state (6-20 months)

– LMN paraplegia– tetraplegia– brainstem signs

Degenerative Myelopathy

• Antemortem Diagnostics MRI

• Diagnosis of exclusion / presumptive diagnosis

– Normal MRI– Cord atrophy

CSF• Normal• High protein

Degenerative Myelopathy

• Genetic test Mizzou OFA

• Samples Cheek swab Whole blood

• Results

• Treatment? No definitive treatment Supportive care

• Exercise/physical therapy• Vitamin supplementation?

Good nutrition Weight control

Degenerative Myelopathy

Degenerative Myelopathy

• The 4 Questions Onset?

• Chronic!

Progression?• Progressive

Symmetry?• Often symmetric

Painful?• No.

Take Home Points

• MRI is the best diagnostic modality to evaluate spinal cord health, determine an accurate prognosis and to plan appropriate therapy

• Not everything is a disc!!!

References• Brewer DM1, Cerda-Gonzalez S, Dewey CW, Diep AN, Van Horne K, McDonough SP. Spinal cord nephroblastoma in dogs: 11

cases (1985-2007). J Am Vet Med Assoc. 2011 Mar 1;238(5):618-24. • Danielsson F1, Sjöström L. Surgical treatment of degenerative lumbosacral stenosis in dogs. Vet Surg. 1999 Mar-

Apr;28(2):91-8.• De Decker S1, De Risio L, Lowrie M, Mauler D, Beltran E, Giedja A, Kenny PJ, Gielen I, Garosi L, Volk H. Cervical vertebral

stenosis associated with a vertebral arch anomaly in the Basset Hound. J Vet Intern Med. 2012 Nov-Dec;26(6):1374-82. • De Risio L1, Sharp NJ, Olby NJ, Muñana KR, Thomas WB. Predictors of outcome after dorsal

decompressive laminectomy for degenerative lumbosacral stenosis in dogs: 69 cases (1987-1997). J Am Vet Med Assoc. 2001 Sep 1;219(5):624-8.

• Dolera M1, Malfassi L1, Bianchi C1, Carrara N1, Finesso S1, Marcarini S1, Mazza G1, Pavesi S1, Sala M1, Urso G1,2 . Frameless stereotactic volumetric modulated arc radiotherapy of brachial plexus tumours in dogs: 10 cases. Br J Radiol. 2017 Jan;90(1069).

• Fisher SC1, Shores A, Simpson ST. Constrictive myelopathy secondary to hypoplasia or aplasia of the thoracolumbar caudalarticular processes in Pugs: 11 cases (1993-2009). J Am Vet Med Assoc. 2013 Jan 15;242(2):223-9.

• Ito D1, Matsunaga S, Jeffery ND, Sasaki N, Nishimura R, Mochizuki M, Kasahara M, Fujiwara R, Ogawa H. Prognostic value of magnetic resonance imaging in dogs with paraplegia caused by thoracolumbar intervertebral disk extrusion: 77 cases (2000-2003). J Am Vet Med Assoc. 2005 Nov 1;227(9):1454-60.

• Levine JM1, Levine GJ, Johnson SI, Kerwin SC, Hettlich BF, Fosgate GT. Evaluation of the success of medical management for presumptive thoracolumbar intervertebral disk herniation in dogs. Vet Surg. 2007 Jul;36(5):482-91.

References• Jeffery ND, Barker AK, Hu HZ, Alcott CJ, Kraus KH, Scanlin EM, Granger N, Levine JM. Factors associated with recovery from

paraplegia in dogs with loss of pain perception in the pelvic limbs following intervertebral disk herniation. J Am Vet Med Assoc. 2016 Feb 15;248(4):386-94.

• Mauler DA1, De Decker S, De Risio L, Volk HA, Dennis R, Gielen I, Van der Vekens E, Goethals K, Van Ham L. Signalment, clinical presentation, and diagnostic findings in 122 dogs with spinal arachnoid diverticula. J Vet Intern Med. 2014 Jan-Feb;28(1):175-81.

• Olby N1, Levine J, Harris T, Muñana K, Skeen T, Sharp N. Long-term functional outcome of dogs with severe injuries of the thoracolumbar spinal cord: 87 cases (1996-2001). J Am Vet Med Assoc. 2003 Mar 15;222(6):762-9.

• Pancotto TE1, Rossmeisl JH Jr, Zimmerman K, Robertson JL, Werre SR. Intramedullary spinal cord neoplasia in 53 dogs (1990-2010): distribution, clinicopathologic characteristics, and clinical behavior. J Vet Intern Med. 2013 Nov-Dec;27(6):1500-8.

• Petersen SA1, Sturges BK, Dickinson PJ, Pollard RE, Kass PH, Kent M, Vernau KM, Lecouteur RA, Higgins RJ. Canine intraspinal meningiomas: imaging features, histopathologic classification, and long-term outcome in 34 dogs. J Vet Intern Med. 2008 Jul-Aug;22(4):946-53.

• Rylander H1, Lipsitz D, Berry WL, Sturges BK, Vernau KM, Dickinson PJ, Añor SA, Higgins RJ, LeCouteur RA.. Retrospective analysis of spinal arachnoid cysts in 14 dogs. J Vet Intern Med. 2002 Nov-Dec;16(6):690-6.

• Sturges BK1, Dickinson PJ, Bollen AW, Koblik PD, Kass PH, Kortz GD, Vernau KM, Knipe MF, Lecouteur RA, Higgins RJ. Magnetic resonance imaging and histological classification of intracranial meningiomas in 112 dogs. J Vet Intern Med. 2008 May-Jun;22(3):586-95.

Any Questions??