Current Strategies for Management of Intervertebral Disc Disease. Ashley Bensfield, DVM, DACVIM (Neurology)

Transcription

1 Current Strategies for Management of Intervertebral Disc Disease. Ashley Bensfield, DVM, DACVIM (Neurology)

2 Objectives Pathophysiology/terminology Where the confusion about IVDD comes from Diagnostics Treatment options Prognosis

3 Pathophysiology/Terminology Type of Intervertebral Disc Disease Hansen Type I Hansen Type II Hansen Type III Myelopathy spinal cord dysfunction Spinal Hyperesthesia misused, but accepted abnormal pain on spinal palpation. Synonym - hyperpathia

4 IVDD Hoerlein 447

5 Pathophysiology/Terminology Upper motor neuron deficits spastic, normoto hyperreflexive Lower motor neuron deficits Decreased tone, normo- to hyporeflexive. Nociception conscious perception of painful stimulus Withdrawal Reflex Reflexive flexion of limb with noxious stimulus to toe

6 Spinal Reflex Arc Platt 21

7 Pathophysiology/Terminology Superficial pain perception Conscious response to mildly noxious stimulus Light pinch, needle prick Deep pain perception Conscious response to bone crushing pain. Paresis inability to move body part with appropriate strength

8 Pathophysiology/Terminology Plegia paralysis inability to move body part Ataxia impaired coordination of movement Proprioceptive Vestibular Cerebellar Proprioception knowledge of where body parts are in space w/o having to look at them.

9 Why is IVDD so confusing? Impossible to find all the information in one place Numerous persistent incorrect anecdotal practices - e.g.: Surgery not needed unless paralyzed Medical management should be tried/failed before surgery considered IVDD is not a systemic disease Length of medical management time is arbitrary

10 References This is a partial list! Brisson, B et al. Comparison of the effect of single-site and multiple-site disk fenestration on the rate of recurrence of the thoracolumbar intervertebral disk herniation in dogs. J Am Vet Med Assoc 2001; 238: Brisson, B et al. Recurrence of thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs after surgical decompression with or without prophylactic fenestration: 265 cases ( ). J Am Vet Med Assoc 2004; 224: De Risio, L et al. Association of clinical and magnetic resonance imaging findings with outcome in dogs with presumptive acute noncompressive nucleus pulposus extrusion: 42 cases ( ). J am Vet Med Assoc 2009:234: Flegel, T et al. Partial Lateral Corpectomy of the Thoracolumbar Spine in 51 Dogs: Assessment of Slot Morphometery and Spinal Cord Decompression. Veterinary Surgery, 40 (2011) Forterre, F et al. Microfenestration Using the CUSA Excel Ultrasonic Aspiration System in Chondrodystrophic Dogs with Thoracolumbar Disk Extrusion: A Descriptive Cadaveric and Clinical Study. Veterinary Surgery, 40 (2011) Gomes, SA, et al. Clinical and magnetic resonance imaging characteristics of thracolumbar intervertebral disk extrusions and protrusions in large breed dogs. Vet Radiol Ultrasound, Vol. 00, No. 0, 2016, pp Hecht, S. et al. Myelography vs. computed tomography in the evaluation of acute thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs. Veterinary Radiology & Ultrasound, Vol. 50, No. 4, 2009, pp Hoerlein, BF. Canine Neurology: Diagnosis and Treatment, 3 rd Ed. W. B. Saunders Company. Philadelphia Israel, SK et al. Relative sensitivity of computed tomograpny and myelography for identification of thoracolumbar intervertebral disk herniations in dogs. Veterinary Radiology & Ultrasound, Vol. 50, No. 3, 2009, pp Jeffrey, N et al. 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;248: Jensen, VF, et al. Quantification of the association between intervertebral disk calcification and disk herniation in Dachshunds. J Am Vet Med Assoc 2008; 233: Levine, JM, et al. Magnetic Resonance Imaging in Dogs with Neurological Impairment Due to acute Thoracic and Lumbar Intervertebral Disk Herniation. J Vet Intern Med. 2009; 23: McKee, WM, et al. Presumptive exercise-associated peracute thoracolumbar disc extrusion in 48 dogs. Veterinary Record (2010)166, Olby, NJ, et al. Prevalence of Urinary Tract Infection in Dogs after Surgery for Thoracolumbar Intervertebral Disc Extrusion. J Vet Intern Med 2010;24: Platt, S and N Olby. BSAVA Manual of Canine and Feline Neurology, 4 th Ed. BSAVA. Glouchester Sharp, NJH and Simon Wheeler. Small Animal Spinal Disorders: Diagnosis and Surgery, 2 nd Ed. Elsevier Mosby. Philadelphia Taylor-Brown, FE, and Steven De Decker. Presumptive acute non-compressive nucleus pulposus extrusion in 11 cats: clinical features, diagnostic imaging findings, treatment and outcome. Journal of Feline Medicine and Surgery. 2017, Vol 19 (1)

11 Hansen Type I IVDD Herniation, rupture, extrusion of nucleus pulposus through a tear in the annulus pulposus Abnormal/unhealthy nucleus pulposus material, unable to withstand normal forces Mineralized nucleus pulposus chondroid degeneration

12 Hansen Type I IVDD Pain and paresis/plegia caused by: compression of spinal cord and nerve roots Bruising type injury to spinal cord Pain from stretching/tearing of disc annulus and dorsal longitudinal ligament

13 Hansen Type III IVDD Catch all phrase Rupture of IVDD capsule under pressure (traumatic) with explosive extrusion of nucleus pulposus. Synonyms: High Velocity Low Volume Extrusion, Missile Disc, Acute Non-compressive Nucleus Pulposus Extrusion (ANNPE), Splatter disc (overlaps with Type I), Liquid Disc

14 Type I and III IVDD Signalment Peracute to gradual (days) onset Spinal hyperesthesia Abnormal posturing Muscle spasms Paresis/paralysis +/- abnormal reflexes +/- decreased or absent nociception

15 Type I and III IVDD Signalment Young (4-6y) chondrodystrophic dog breeds, and middle aged (6-8) non-chondrodystrophic. In young dachshunds association btwn number of mineralized discs on radiographs and risk for future Type I IVDD Young to middle aged cats Type III associated with exercise/activity Similar presentation to FCE and/or spinal trauma

16 Neurolocalization UMN signs generally carry a better prognosis than LMN signs. LMN signs - dysfunction of spinal cord intumescence (neuron cell bodies for the LMNs reside). Damage to cell body results in permanent loss of that neuron. UMN signs axon damage/dysfunction. Spinal cord/nerve axons have much greater ability to regenerate/resist injury. Hyperesthesia if present, site of pain usually indicates location of IVDD. Cutaneous Trunci reflex 1-2 segments caudal to site of injury

17 Schiff-Sherrington Posture Acute thoracolumbar junction spinal cord injury Loss of upper motor neuron inhibition to forelimbs Increased extensor tone in forelimbs Forelimb proprioception, voluntary motor and reflexes normal to increased Mistaken for Opisthotonos SSP no central vestibular or RAAS signs. Does not give information about prognosis.

18 Platt 6

19 Nerve Root Signature Sharp 93

20 Myelomalacia Spinal cord Softening Ischemic death of the spinal cord Can be focal, but often progresses to the ascendingdescending form. Fatal due to progression cranially to the areas of the spinal cord controlling respiratory muscles Occurs in 10% of patients with acute paraplegia and loss of nociception May not manifest for up to 7-10 days (usually under 5) No treatment, including surgery, shown to prevent.

21 Myelomalacia Clinical signs Ascending cutaneous trunci reflex cutoff This reflex should not decrease further after 24hrs postop or post-disc extrusion. Track daily by marking patient s back with permanent marker Flaccid abdomen and pelvic limbs Patient appears restless/uncomfortable May be hyper- or hypothermic Progressive respiratory paralysis

22 Sharp 128

23 Hansen Type II IVDD Thickening and protrusion of annulus fibrosus Fibrous metaplasia of nucleus pulposus May be associated with spondylosis deformans (ankylosing). Paresis caused by compression of spinal cord and/or nerve roots. May result in spinal cord gliosis and nerve atrophy Pain caused by nerve root compression

24 Type II IVDD Signalment Older, generally large breed dogs or older cats Chronic slowly progressive paresis +/- spinal pain Often reluctant to jump or use stairs getting old, slowing down. Can acutely worsen +/- nerve root signature or paresthesia

25 Differential Diagnoses Other causes of pain and/or myelopathy FCE, spinal fracture, discospondylitis, neoplasia, myelitis (infectious/auto-immune), Deg. Myel., COMS. Other causes of LMN weakness Neuropathy, myopathy, junctionopathy (MG), electrolyte disturbances, diabetes mellitus, plexus avulsion. General causes of weakness Hypotension, hypoglycemia, hemoabdomen, etc. Orthopedic disease/joint pain Bilateral CCL disease, hip dysplasia, polyarthropathy

26 Diagnostics Physical Exam General PE Back pain and abdominal pain can be hard to differentiate Particular attention to causes of weakness Thorough auscultation, palpate pulses, ballotte abdomen, check MM color. Thorough orthopedic exam

27 Diagnostics-Neurological Examination Importance of performing neuro exam on normal patients. Make sure patient adequately supported to differentiate weakness from CP deficit. Should be mentally appropriate Cranial nerves Possible Horner s Syndrome if cervical/high thoracic. Otherwise normal. Nociception-if limbs move voluntarily, pain sensation should be present no need to aggressively test. Reflex does not equal nociception! Remember tail/perineum!

28 Diagnostics- Neurological Examination Spinal palpation, neck range of motion If suspect animal is painful, do this step last! Neck pain and partial seizures can look similar Neck pain dogs will hunch their T/L spine too. Voluntary Motor assessment Assess patients in quiet room On the floor Good footing Olby Fig.7-2, 3 rd Ed

29 Diagnostics Minimum Database Complete blood count (with manual diff) Chemistry profile (with CPK) Urinalysis (with sediment) +/- Tick testing Aspergillus antigen German Shepherds DM genetic test Boxers, GSD, Corgi +/- Neoplasia screening if over 8yrs (3-view CXR/AUS) Viral testing for cats. ECG/BP if renal dz, arrhythmia, poor pulses, etc.

30 Diagnostics - Imaging Radiographs Low yield for IVDD Provides information about Congenital malformations Spinal fracture Osteolytic disease cancer, osteomyelitis, discospondylitis, etc. V/D views less helpful, especially if not sedated COLLIMATE not a time for cat/dog-o-gram

31 Diagnostics - Myelography Technically challenging but inexpensive. General anesthesia, iodinated compound injected into epidural space. Causes reactive meningitis x 2 weeks and small area of permanent focal damage to lumbar spinal cord where needle penetrates. May cause seizures Highlights extradural compression Does not always provide accurate side/site Does not give information about health of spinal cord. Helpful in evaluating Type II IVDD for dynamic compression Does not differentiate neoplasia, etc. from IVDD.

32 Diagnostics CT +/- myelography Rapidly identify acute, compressive, Type I, thoracolumbar IVDD in young dogs. Site, side, extent Not as helpful for differentiating acute/chronic sites. Does not provide information about health of spinal cord. More expensive than myelography, less expensive than MRI Helpful in evaluating Type II lesions for dynamic compression with myelography. Does not always differentiate IVDD from neoplasia, etc. IV contrast administration can help.

33 Hansen Type I IVDD

34 Hansen Type I IVDD

35 Diagnostics - MRI Best modality for evaluating IVD, spinal cord, and nerve roots Not as good bone detail as CT. Evaluates spinal cord for edema/gliosis. More prognostic information than CT or myelography More readily differentiates acute vs. chronic sites. Can evaluate dynamic compression More time consuming and expensive than myelography or CT.

36 Hansen Type I IVDD

37 Hansen Type II IVDD

38 Treatment options Medical Type I Rest, anti-inflammatory medication, pain management, bladder management 6 weeks cage rest, no jumping/stairs for life NSAID OR anti-inflammatory dose of steroids days only. Manage secondary damage hydration, free radicals, etc. +/- muscle relaxer, opioid, and/or gabapentin +/- bladder management U-cath, intermittent catheterization, manual expression. Prazosin (1mg/15kg TID) +/- diazepam, +/- bethanechol

39 Treatment Options - Medical Type II Physical therapy and/or intermittent cage rest. Long term vs. pulse anti-inflammatory medications Long term gabapentin and/or tramadol. No jumping or stairs +/- bladder management

40 Treatment Options - Surgical Hemilaminectomy Dorsal Laminectomy Lateral Corpectomy Ventral Slot Distraction/fusion Fenestration Reduces risk of future Type I

41 Treatment Post-OP 2-4 weeks strict rest, no jumping/stairs for life Gradual return to walking, then running, and playing. Anti-inflammatory therapy x days Tramadol, gabapentin as needed Muscle relaxer diazepam, methocarbamol, 5-7 days

42 Treatment Options - Complementary Acupuncture Laser Therapy for muscle soreness. Physical therapy when? How much? Massage Ice/Hot packing

43 Prognosis Type I or III, acute Neurolocalization C1-C5 50 %, 30-50% Relapse C6-T2 50%, 30-50% Relapse T3-L3 70%, 30% Relapse L4-S %, ~50% relapse Pain + Medical Pain + Sx Pain - Medical Pain - Sx 90-95% N/A N/A 70-95% N/A N/A 90-95% 10% 50-55%, Timing??? 70-90% Less than 10% 10-30%, Timing??? **with pain +, no change in prognosis for surgical success ~8wks from time of injury. However, if become pain -, prognosis decreases as above.**

44 Prognosis Type I, chronic, pain + Because of additional scar tissue, prognosis with surgery decreased by about 20-25% if surgery performed >8wks after herniation

45 Prognosis Type II Degree of spinal cord atrophy difficult to quantify. No improvement in neurological grade with surgery if due to atrophy Decreased functional reserve More likely to be worse following surgery Minor trauma during surgery = last straw effect Surgical vs. conservative management have similar outcomes Indications to try surgery Chronic pain Paralysis Improved neurological grade with anti-inflammatories. Owner goals try to prevent further worsening knowing risk

46 References Brisson, B et al. Comparison of the effect of single-site and multiple-site disk fenestration on the rate of recurrence of the thoracolumbar intervertebral disk herniation in dogs. J Am Vet Med Assoc 2001; 238: Brisson, B et al. Recurrence of thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs after surgical decompression with or without prophylactic fenestration: 265 cases ( ). J Am Vet Med Assoc 2004; 224: De Risio, L et al. Association of clinical and magnetic resonance imaging findings with outcome in dogs with presumptive acute noncompressive nucleus pulposus extrusion: 42 cases ( ). J am Vet Med Assoc 2009:234: Flegel, T et al. Partial Lateral Corpectomy of the Thoracolumbar Spine in 51 Dogs: Assessment of Slot Morphometery and Spinal Cord Decompression. Veterinary Surgery, 40 (2011) Forterre, F et al. Microfenestration Using the CUSA Excel Ultrasonic Aspiration System in Chondrodystrophic Dogs with Thoracolumbar Disk Extrusion: A Descriptive Cadaveric and Clinical Study. Veterinary Surgery, 40 (2011) Gomes, SA, et al. Clinical and magnetic resonance imaging characteristics of thracolumbar intervertebral disk extrusions and protrusions in large breed dogs. Vet Radiol Ultrasound, Vol. 00, No. 0, 2016, pp Hecht, S. et al. Myelography vs. computed tomography in the evaluation of acute thoracolumbar intervertebral disk extrusion in chondrodystrophic dogs. Veterinary Radiology & Ultrasound, Vol. 50, No. 4, 2009, pp Hoerlein, BF. Canine Neurology: Diagnosis and Treatment, 3 rd Ed. W. B. Saunders Company. Philadelphia Israel, SK et al. Relative sensitivity of computed tomograpny and myelography for identification of thoracolumbar intervertebral disk herniations in dogs. Veterinary Radiology & Ultrasound, Vol. 50, No. 3, 2009, pp Jeffrey, N et al. 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;248: Jensen, VF, et al. Quantification of the association between intervertebral disk calcification and disk herniation in Dachshunds. J Am Vet Med Assoc 2008; 233: Levine, JM, et al. Magnetic Resonance Imaging in Dogs with Neurological Impairment Due to acute Thoracic and Lumbar Intervertebral Disk Herniation. J Vet Intern Med. 2009; 23: McKee, WM, et al. Presumptive exercise-associated peracute thoracolumbar disc extrusion in 48 dogs. Veterinary Record (2010)166, Olby, NJ, et al. Prevalence of Urinary Tract Infection in Dogs after Surgery for Thoracolumbar Intervertebral Disc Extrusion. J Vet Intern Med 2010;24: Platt, S and N Olby. BSAVA Manual of Canine and Feline Neurology, 4 th Ed. BSAVA. Glouchester Sharp, NJH and Simon Wheeler. Small Animal Spinal Disorders: Diagnosis and Surgery, 2 nd Ed. Elsevier Mosby. Philadelphia Taylor-Brown, FE, and Steven De Decker. Presumptive acute non-compressive nucleus pulposus extrusion in 11 cats: clinical features, diagnostic imaging findings, treatment and outcome. Journal of Feline Medicine and Surgery. 2017, Vol 19 (1)

47 Questions?

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