SAS Exam 2 - M

common upper airway diseases

• Brachycephalic Obstruction airway syndrome (BOAS)

• laryngeal paralysis

• obstruction:

  • neoplasia

  • granuloma

• foreign body

• trauma:

  • obstruction

  • wounds

  • pneumothorax

  • pneumonmediastinum

preoperative management for upper airway issues

• identify respiratory difficulty

  • open-mouth breathing

  • abducted forelimbs - cowboy walk look

  • labored breathing

  • restlessness

  • muddy color cyanotic look

• use minimal restraint

• oxygen support - important

• sedation - to calm them down so they can take better breaths

  • Butorphanol

  • Acepromazine

• ± cooling - especially bulldogs

Anesthetic management for upper airway issues

• extreme anesthetic risk!

• greatest danger: induction and recovery

• pre-oxygenation - always

• examine the upper airway at induction

• rapid endotracheal intubation (ET tube)

  • be prepared for a temporary tracheostomy

• recovery

  • calm, quiet

  • oxygen

  • ventilation support

  • dont take tube out until they are chewing the trach tube

Brachycephalic obstruction airway syndrome (BOAS)

• these dogs walk around and you can hear them breahening / snoring

• signalment

  • Brachycephalic breeds

    • compressed face

    • poorly developed nares

    • distorted nasopharynx

    • redundant tissues

  • often young / early age

• syndrome

  • stenotic nares

  • soft palate elongation

  • laryngeal saccule eversion

  • hypoplastic trachea

• clinical signs worsen with time - treat early

• clinical signs

  • stertor (increased nasal sounds)

  • stridor (high pitched wheezing)

  • coughing, gagging

  • exercise intolerance

  • harder to breath at night so restless sleeping pattern

  • collapse

  • dyspnea

BOAS diagnostic workup

• Blood work - usually boring

  • neutrophilia with left shift (if aspiration pneumonia)

• thoracic radiographs

  • rule out aspiration pneumonia

  • identify a hypoplastic trachea

  • identify concurrent tracheal collapse

• ± cervical radiographs

  • identify an elongated soft palate

  • evaluate for any cervical masses

  • evaluate for any cervical tracheal collapse

• airway examination

  • one anesthetic episode

  • perform when ready to do surgery

BOAS stenotic nares

• abnormally narrow nostrils

  • congenital malformation of nasal cartilages

• why a concern

  • normal resistance to airflow is 76-80%

  • airway pressures increase with narrowing

  • airway tissues will eventually collapse

• surgical management - open the nares

  • multiple techniques

    • cartilage resection / suture anastomosis

    • cartilage amputation (traders technique)

BOAS Elongated soft palate

• palate extends >1-3mm beyond the epiglottis

  • subjective evaluation - caution

  • can use tonsils as a guideline

• laryngeal mucosa becomes inflamed

• why a concern

  • laryngeal edema = airway obstruction

  • chronic upper airway stress

  • like having curtains over open window decreased airflow the soft palate drops down over the epiglottis

• surgical technique (staphylectomy/palatoplasty) - shortening the soft palate

  • remove elongated portion of the palate

  • trim to level of tonsils / just past tip of epiglottis

• complications

  • laryngeal edema

    • airway obstruction

    • short term

  • hemorrhage

  • aspiration

BOAS everted laryngeal saccules

• prolapse of mucosa lining the laryngeal crypts

  • response to chronic high upper airway pressures

• least common of the BAS complex

• why a concern

  • further inhibit airflow, increases mucosal irritation

  • first stage of laryngeal collapse

• surgical technique - cut them out but careful of vocal folds

  • extubate the patient temporarily

  • grasp and pull with forceps

  • resect saccule at its base with metzenbaum scissors

  • bleeding is controlled with direct pressure (from the ET tube)

• happens due to chronic stress

BOAS

• Hypoplastic trachea

  • tracheal diameter to small: thoracic inlet <0.2 - have to do after a year old b/c will grow

  • cannot surgically correct

• laryngeal collapse: secondary due to chronic stress

  • due to chronic upper airway obstruction / airway resistance

  • 3 stages

    • I - everted laryngeal saccules

    • II - I + collapsed cunieform cartilages (red)

    • III - I + II + collapsed corniculate cartilages (green) - everything collapsed down cant breath at all

  • treatment

    • laryngectomy

    • permanent tracheostomy

Laryngeal paralysis

• complete or partial failure of the arytenoid cartilages

  • failure of cartilage to open up during inspiration

  • recurrent laryngeal nerve

  • cricoarytenoideus dorsalis muscle

• congenital

  • Rottweiler, Dalmation, White-coated German shepherd, Great pyrenees, Leonburger, Bull terrier, Bouvier des flandres

• acquired - most of the time

  • causes

    • idiopathic****

    • trauma

    • systemic disease

    • Iatrogenic

  • signalment

    • large breed dogs > medium / small breed

    • labrador, irish setter, saint bernard

• clinical presentation

  • inspiratory stridor

  • voice change

  • exercise intolerance

  • coughing, gagging

  • anxious

  • collapse

  • ± generalized weakness, muscle atrophy (goolp)

• clinical signs worsen with time!

  • often starts as unilateral then progresses to bilateral paralysis

  • voice change unilateral

  • bilateral = more clinical signs

Laryngeal paralysis examination

• light plane of anesthesia (induction)

  • opioid premedication + propofol ± doxapram

• evaluate for purposeful movement of arytenoid cartilages

  • abduction of arytenoids and vocal folds on inspiration

  • caution: fluttering, paradoxical movement

• surgical techniques

  • complicated anatomy

    • goal:

      • reduce the obstruction within the airway

      • reduce airway resistance

    • unilateral arytenoid lateralization - most common

      • abducts one side of the arytenoid cartilages - we only do surgery on one side no matter if both are affected

• complication with surgery (10-60%)

  • failure of the procedure

    • higher with mineralization of cartilages

      • cartilage fracture

    • suture breakage

  • aspiration pneumonia - biggest risk especially first 24hours but life long problem

    • less of a risk with unilateral lateralization

• prognosis

  • good - 90% improvement in clinical signs

• life long risk

  • aspiration pneumonia

  • continued heat / exercise intolerance

  • progression of polyneuropathy - if GOLPP is present

Lung lobectomy

• Normal lung volume

  • right lung - 58%

  • left lung - 42%

• lobectomy: partial or complete removal of a lung

  • dogs easily tolerate up to 58% removal

• compensation occurs via:

  • hyperinflation of the remaining lung

  • enlargement of the alveolar air spaces

  • thinning of the alveolar capillary tissue barrier

• indications

  • partial lobectomy

    • focal lesion at peripheral ½ to 2/3 of lung lobe

      • neoplasia

      • granuloma

      • bulla

    • biopsy

  • complete lobectomy

    • large amount of purulent material (abscess)

    • trauma

    • lung love torsion

    • large / multifocal lesion

      • neoplasia

      • bulla

complete lobectomy

• intercostal thoracotomy or median sternotomy

• remove lung at pedicle

  • ligate main artery, bronchus, vein

  • all the way to hiatus

complete lobectomy - Torsion

• signalment - deep, narrow chest

• right cranial and middle are most common

• venous and bronchus obstruction arterial flow remains

• lobe becomes congested and consolidated

• can be associated with:

  • chronic respiratory disease

  • chylothorax

  • trauma

  • thoracic surgery

  • neoplasia

  • idiopathic*** most common

• surgery

  • complete lobectomy WITHOUT untwisting the lobe

Traumatic and congenital diaphragmatic hernia

• very common

• continuity of the diaphragm is disrupted

  • abdominal organs migrate into the thorax

• due to an alteration in pressure gradient

  • acute

    • shock, associated injuries, respiratory difficulty

  • chronic

    • respiratory dyspnea, exercise intolerance, nonspecific (ADR)

• signalment: no breed predisposition

• tear often occur in weakest area - through muscle

• diagnostic evaluation

  • thoracic radiographs (65% accurate)

    • pleural effusion

    • gas/soft tissue opacity within the thoracic cavity

    • stomach against the diaphragm

    • loss of diaphragm silhouette

  • ultrasound

  • CT scan

• liver is the most herniated organ, rarely stomach

Diaphragmatic hernia - Traumatic

• Surgical repair - be prepared for anything!

  • abdominal exploratory

  • identify hernia and carefully reduce contents

    • caution - adhesions could be present

  • close diaphragmatic defect

    • account for tension

    • freshen edges if chronic

    • suture defect closed - simple continuous with absorbable suture

      • 3-0 PDS

      • suture from dorsal (deep) to ventral (superficial)

  • remove air from thoracic cavity - with needle and syringe and pull air out so lungs can re-expand

  • do NOT re-expand lungs manually!!!

    • can cause re-expansion pulmonary edema

Diaphragmatic hernia - Congenital

• Peritoneopericardia d. hernia (PPDH)

  • congenital common cavity between pericardium and peritoneal cavity

  • breeds: cocker spaniel, weimaraner, himalayan, DLH

  • clinical signs:

    • asymptomatic - most common

    • respiratory dyspnea

  • look for other congenital defects

  • diagnostic evaluation: thoracic radiographs

    • enlarged, globoid cardiac silhouette

    • ± gas opacity in the cardiac silhouette

    • pericardial effusion

• surgical repair

  • perform as early as possible (8-16 weeks of age)

  • abdominal exploratory

  • gently replace abdominal organs

    • enlarge diaphragmatic defect if needed

  • do not close the pericardial sac

  • close the diaphragmatic defect

  • remove air from thoracic cavity

• complications (traumatic and congenital)

  • re-expansion pulmonary edema

  • abdominal compartment syndrome

  • acute respiratory distress

Lymph nodes palpable when enlarged

• maxillary

• accessory axillary

• cervical

• femoral

• retropharyngeal

• sublumbar***

• mesenteric***

Lymphadenomegaly

• causes

  • infection

  • inflammation

  • neoplasia (metastatic, primary)

  • systemic disease

• localized or generalized

• size does not correlate with disease

• palpation is important

  • painful

    • suppurative lymphadenitis (infection)

  • non-painful

    • lymphoid neoplasia

  • fixed

    • metastatic neoplasia

    • fungal

fine needle aspiration lymph nodes

• screening tool

  • performed as a first step

• cellular sample only

• specific but not sensitive

• etiologies

  • bacterial

  • fungal

  • neoplasia - mesenchymal, epithelial

why biopsy lymph nodes

• Diagnosis

  • non-diagnostic FNA

  • neoplasia

  • culture

• disease staging

• develop treatment plans

Needle (tru cut) biopsy techniques

• septic technique

• large bore (14-16g)

• indication

  • larger node

  • safe location

• core of tissue

  • fairly small sample size

• easy / quick

• expensive

Incisional (wedge) biopsy techniques

• indications

  • regional anatomy concern

  • smaller size of node

  • more difficult location

• aseptic technique

• stabilize node

• wedge-shaped incision

• capsule sutured closed

Excisional (lymphadenectomy) biopsy technique

• indications

  • smaller node

  • evaluate for metastasis

    • does not prevent metastasis

• aseptic technique

• surgical approach to node

• dissection of the node

• ligation of the blood vessels

splenic anatomy

• gastrosplenic ligament

• vascular supply

  • celiac artery →

  • splenic artery

    • A. branch to the pancreas

    • left gastroepiploic a

    • short gastric aa

splenomegaly

• Diffuse

  • congestion

    • splenic torsion*

    • right-sided heart failure

    • gastric dilatation - volvulus (GDV)*

    • drugs

    • infection*

    • immune-mediated*

    • neoplasia-lymphoma

• focal

  • nodular regeneration

  • hematoma*

  • trauma*

  • neoplasia*

splenic torsion

• spleen twists on its vascular pedicle

• large breed dogs

• uncommon

• acute

  • shock, anorexia, vomiting, diarrhea, abdominal pain, enlarged spleen

• chronic

  • anorexia, vomiting, diarrhea, abdominal pain, enlarged spleen, hemoglobinuria

• radiographs

  • abnormal location

  • mass effect

  • gas bubbles

  • comma-shaped

• ultrasound

  • variable echotexture

  • dilated vessels - gas bubbles

  • thrombi

• treatment

• acute more urgent than chronic

• cardiovascular stabilization

• antibiotics - Unasyn

• electrocardiogram - can cause issues with rhyme of heart so want ECG

  • DO NOT UN-TWIST

    • Necrotic debris can enter systemic circulation

• splenectomy

  • cannot and should not un-twist

Neoplasia of the spleen

• benign or malignant

• very common

• large breed dogs » small breed dogs

• acute

  • shock, enlarged abdomen, abdominal mass, fluid wave, lethargic, vomiting, abdominal pain

• chronic

  • same as acute but episodic presentation

• diagnosis

  • abdominal radiographs

    • mass-effect

    • peritoneal effusion

  • thoracic radiographs

    • metastasis

  • ultrasound

    • mixed echotexture

    • cavitated lesions

    • enlarged spleen

spleen neoplasia

• differentials

  • non-neoplastic

    • hematoma

• benign neoplasia

  • Lipoma / myelolipoma

  • hemangioma

  • fibroma

• malignant neoplasia

  • Hemangiosarcoma* - most common

  • fibrosarcoma

  • liposarcoma

  • mast cell tumor

• treatment

  • cardiovascular stabilization

  • electrocardiogram

  • ± blood transfusion

  • splenectomy

splenic fine needle aspiration

• advantage:

  • samples obtained percutaneously

  • cheap, easy

• indications:

  • concern for diffuse disease or definitive mass

• caution:

  • avoid cavitary lesions

  • major hemorrhage can occur

• usually non-diagnostic for neoplastic masses

splenic biopsy

• surgical approach to the spleen

• obtain more tissue for histopathology

  • diffuse disease

  • small/focal mass

• obtain tissue for culture

• technique

  • incision into the spleen to remove tissue

  • close capsule with suture

  • direct pressure for hemostasis

splenectomy

• preferred method

• indications

  • neoplasia

  • severe trauma

  • immune-mediated disease

• concern

  • large-volume blood loss

• classic approach

  • exteriorize and isolate spleen

  • dissect, ligate, and divide all hilar vessels

    • do not damage the short gastric aa.

    • time consuming

    • more option for hemorrhage

• alternate approach

  • abdominal exploration

  • exteriorize and isolate the spleen

  • identify the splenic artery and vein distal to:

    • pancreatic branch

    • short gastric aa

    • left gastroepiploic a

  • quicker

  • ok for normal spleen with no adhesions

splenectomy complications and post op considerations

• hemorrhage

  • hemoabdomen prior to surgery

  • breakdown of adhesions at surgery

    • resist this temptation

  • mass rupture with handling at surgery

  • ligature slippage

  • blood contained within the spleen itself

• blood transfusion

• electrocardiogram

  • you will see ventricular arrhythmias

• crystalloid/colloid fluid support

• oxygen therapy

• monitor coagulation profiles (PT/PTT)

oncology patient assessment

• history and physical exam

• visual inspection

• mass palpation

• evaluate

  • gross appearance

  • consistency

  • size

  • mobility

• palpation of regional lymph nodes

• secondary effects of a tumor present

  • anemia

  • hypercalcemia

  • vomiting / diarrhea

oncology fine needle aspiration

• cytological evaluation

  • cellularity

• definitive diagnosis

  • lymphoma

  • melanoma

  • mast cell tumor

• supportive information

• inflammation often accompanies tumors

oncology biopsy

• obtain a diagnosis

• need to know tumor behavior

  • degree of local invasion

  • metastatic potential

  • biologic activity (ie. histamine release)

• pre or postoperative

  • will the information affect case management

  • can i harm the patient

• what technique consider

  • invasiveness of the procedure

  • potential for intra-cavitary hemorrhage

  • potential to seed tumor cells

biopsy oncology

Incisional / TruCut

• removal of part of the tumor

• specific behavior of tumor may affect treatment plan/owners decision

• disadvantage

  • requires a second surgery

  • seed tumor cells if not careful

Excisional:

• remove entire tumor with normal tissue

• allows for a single procedure

• disadvantage:

  • surgical excision may not be complete

  • may remove too move tissue

biopsy incisional vs excisional

Incisional:

• large skin mass

• fixed mass

• mass near important structures

• musculoskeletal

Excisional:

• small, movable skin masses

• internal organs

• finances

tumor staging

• Diagnostic process

  • to evaluate for progression / extent of disease

• tests are dictated by tumor type

  • often performed after a diagnosis is made

• bloodwork

  • complete blood count

  • serum biochemistry panel

  • urinalysis

• radiography

  • three view thoracic

• ultrasonography - abdomen

  • identify masses / infiltration

  • obtain samples for cytology

  • surgical planning

• lymph node aspiration

  • enlarged nodes

  • draining / sentinel lymph nodes

• computed tomography

• magnetic resonance imaging

oncology surgical principles

• one and done

  • normal anatomy

  • less chance of tumor metastasis

  • easier closure

  • less chance of surgical spread of tumor

• excise all neoplastic tissue

  • tumor itself

  • biopsy or cytology tracts

oncology surgical principles margin of excision

• Aggressiveness (surgical dose)

  • intralesional (debulking)

  • marginal

  • wide

  • radical

• dependent on

  • tumor type

  • tumor grade

  • location of tumor

• intralesional

  • leave “gross” tumor behind

• marginal

  • just peripheral to pseudocapsule

  • reactive zone

  • used for benign

    • lipoma

  • satellite tumor

  • common without a prior biopsy

• wide and radical

  • curative-intent

  • recommended for solid tumors

  • excise a margin of normal tissue

  • deep

    • 1 or 2 facial planes

  • radical

    • entire tissue compartment

    • splenectomy

    • amputation

    • mammary chain

oncology post-removal biopsy

• Do this! do this! do this!

• allows for margin assessment

  • 3D margins: lateral and deep

• dictates adjunctive treatment plan

mechanisms of trauma in the CNS

• contusion

  • spinal instability

    • fracture

    • luxation

  • disc herniation

  • blunt trauma

• compression

  • disc herniation

  • disc protrusion

  • spinal instability

    • fracture

    • luxation

  • blunt trauma

  • localized hemorrhage

  • spinal cord > brain

  • primary damage

    • mechanical trauma

    • axonal injury

    • hemorrhage

    • edema

  • secondary biochemical effects

    • demyelination

    • neuronal and glial cell necrosis

    • inflammatory response - IL, TNF, NO

  • severity depends on:

    • etiology

    • speed of onset

    • duration

    • location

    • amount of compression

clinical history for CNS issues

• environment

• how did the trauma occur

• duration since trauma

• how did the patient appear immediately after the trauma

• has the patient had a change in mentation

• any medications administered

physical examination for CNS patients

• evaluate all body systems

• neurologic examination

  • complete

  • partial - do not manipulate spinal trauma

    • gentle palpation of vertebral column

    • spinal reflexes

    • severity of neurologic deficits

• neurologic localization

  • brain

  • spinal cord

• goal

  • determine most likely cause

  • determine potential prognosis

triage for CNS trauma

• treat shock

  • fluids, ECG, oxygen, maintain patent airway

  • monitor vitals

• decide if spinal trauma is present

  • defect on paraspinal palpation

  • neurologic signs in limbs/reflexes

• decide if head trauma is present

  • anisocoria

  • pupil size

  • nystagmus

  • mentation/level of consciousness

  • bleeding - nose, ear, eye

• cushing response

  • nervous system response to increased ICP

  • severe cases of head injury/brain herniation

  • what do you see

    • increased blood pressure, irregular breathing, reflex bradycardia

Treatment - head trauma

• serial neurologic exams

• keep head elevated

• fluid therapy

• oxygen

• ventilatory support, if needed

• monitor electrocardiogram

• pain medications - opioids

• mannitol (0.5-1 g/kg) over 20 minutes - removes edema in brain

  • osmotic diuretic

  • can do 2-3 doses

• Dexamethasone (0.1 mg/kg once)

  • follow up only after 3rd dose of mannitol, if not effective

  • decreases edema

• surgical intervention

  • subdural hematoma

  • depressed skull fracture

  • debride contaminated / necrotic tissue

  • stabilize intracranial pressure

• procedure

  • craniectomy

    • decrease pressure by 15%

  • durotomy

    • decrease pressure by 65%

intervertebral disk disease anatomy

• #1 most common in general practice

  • 2 components

    • annulus fibrosus

      • parallel arrangement of lamellae

      • thicker ventrally

    • nucleus pulposus

      • located centrally (eccentric)

  • cartilagenous vertebral end plates

    • source of nutrients via diffusion

function of the intervertebral disk

• shock absorption and distribution

  • determined by:

    • proteoglycans in the nucleus

    • elasticity of the annulus

• flexible enough to allow/rigid enough to endure:

  • bending

  • shear

  • torsion

  • compression

  • tension

intervertebral disk herniation

• chondroid metaplasia

  • loss of water content

  • deposition of mineral

  • alteration of proteoglycans

    • equals intradiskal pressure

• signalment

  • chondrodystrophic breeds

  • dachshund - 10x increased risk

  • 3-5yr (TL), 8-12yr (cervical)

• clinical presentation

  • compressive myelopathy

  • contusion injury

• acute, progressive

• severity may depend on factors:

  • location of compression

  • duration of compression

  • velocity / force of herniation

  • volume of disc herniation

clinical presentation for intervertebral disk herniation

• paraspinal hyperesthesia

  • abdominal discomfort

  • reluctance to ambulate

  • hunched back

  • guarded neck

  • vocalization

  • forelimb lameness

    • nerve root signature

  • ataxia / paresis

  • paralysis (plegia)

cervical or thoracolumbar intervertebral disk herniation

• Cervical

  • 25-33% incidence

  • C2-3 to C5-6

  • pain more common

    • up to 61%

• thoracolumbar

  • 66-75% incidence

  • T10-11 to L6-7

  • pain + neurologic deficits more common

Diagnosis of intervertebral disk herniation

• spinal radiographs

  • 35% accurate

  • rule out differentials

    • diskospondylitis

    • neoplasia

    • trauma

  • identify

    • foraminal changes / mineralization

    • narrowing/wedging of disc space

    • mineralized disk IN SITU

• CT

• MRI

management for intervertebral disk herniation

• medical management

  • goals

    • reduce inflammation

    • disk resorption

  • decreased motion

    • crate rest x 4 weeks minimum

    • leash walks only

  • pain medication

    • Gabapentin - 10-14mg/kg TID

    • NSAID (carprofen, meloxicam)

    • ± amantadine (4mg/kg SID-BID)

  • reserved for

    • pain only

    • ambulatory paresis

• surgical management

  • goal

    • remove compression

    • reduce inflammation/pain

  • reserved for:

    • nonambulatory paresis

    • plegia/paralysis

  • surgical procedure

    • ventral slot diskectomy (cervical)

    • hemilaminectomy (TL)

  • follow with medical management protocol

Intervertebral disk herniation recurrence

• 15-20% - on average but increases with mineralized disk in situ

• 50% risk with >5 mineralized disk IN SITU

• risk increases with inappropriate management - they can herniate again so 4-6 weeks rest important

percutaneous laser disk ablation (PLDA) for intervertebral disk herniation

• approach to remove (ablate) the nucleus pulposus

• performed from T10-11 thru L5-6

• intended to reduce risk of recurrence

  • 15-20% → 4.5% (require surgery)

Intervertebral disk protrusion

• 2nd most common in GP

• Fibroid metaplasia

  • dorsal annulus weakens

  • nucleus pulposus protrudes into the annulus

• effects

  • ischemic myelopathy

  • decreased blood circulation

  • demyelination / axonal degeneration

• slow, progressive myelopathy

• signalment

  • large breed

  • non-chondrodystrophic

  • middle-aged to older (5-12 yrs)

• scuffing toe nails

• difficult to get up, way more common in back legs

clinical presentation and diagnosis of intervertebral disk protrusion

• slow, progressive ataxia (weakness)

  • weeks to months

• pain at the site of protrusion

• TL »» cervical

• differential diagnoses

  • neoplasia

  • degenerative myelopathy

  • infection/inflammation

  • orthopedic disease

• diagnosis

  • radiographs

    • rule out other differentials

  • MRI

treatment for intervertebral disk protrusion

• medical

  • often the preferred treatment

  • pain medication

    • Gabapentin - 10-15mg/kg TID

    • NSAID (carprofen, meloxicam)

  • nursing /supportive care

    • sling support / ambulatory assistance

    • padded bedding

    • good footing

    • bladder management (if needed)

• surgical

  • goals

    • decompression

    • restoration of blood flow

    • axonal regeneration

  • procedure

    • laminectomy

  • acute worsening of neurologic signs

  • deterioration of signs within 1 year

  • continue medical management protocol

  • you dont really see improvement

anatomy of lumbosacral disease

• L7 to S1-3

• collection of nerve roots (cauda equina)

• sacrum is attached to the pelvis

  • joint movement is different

  • mainly flexion

  • restricted degrees of lateral bending, rotation, extension

causes of lumbosacral disease

• degenerative

  • disc protrusion* most cases

  • ligamentum flavum degeneration

  • dorsal longitudinal ligament hypertrophy

  • articular facet hypertrophy

  • spondylosis

  • instability*

• congenital - very rare

  • stenosis of canal

  • malarticulation / malformation

  • transitional vertebrae

  • osteochondrosis of vertebral end plate

clinical presentation of lumbosacral disease

• signalment

  • large-breed, middle-aged

  • active, working (German shepherd)

• signs

  • reluctance to jump

  • less active

  • stiff hind limb gait - not front legs

  • low tail carriage - b/c lessens pain so if you lift tail will have pain

  • urinary or fecal incontinence

  • lower back pain/ weakness due to vascular compromise and or nerve root compression

  • pain ± neurologic deficits

Diagnosis of lumbosacral disease

• differentials

  • neoplasia

  • hip dysplasia

  • degenerative myelopathy

• elicit pain on examination - tail raise

• varying degrees of nerve deficits

  • sacral, caudal, sciatic nerves

• LMN (L4-S3)

• abnormal perineal sensation

• patellar “pseudohyperreflexia” - exaggerated reflex

  • sciatic affected, patellar reflex spared - sciatic cant counter the femoral nerve action

  • due to loss of antagonistic muscle action

  • femoral nerve not affected since femoral is higher up

• rectal exam

  • palpate dorsal/pressure b/c they will show pain also stricture of rectum

• radiographs

  • spondylosis

  • narrowed disc

  • endplate sclerosis

  • transitional vertebrae

• CT

• MRI - way to go but CT will work

Treatment of lumbosacral disease

• medical

  • pain medication

    • gabapentin

    • NSAID

  • rest*

  • epidural steroid injections

    • methylprednisolone acetate x3 injections

      • initial 2 weeks, 6 weeks

    • 79% improved; 50% resolved pain

  • appropriate bedding

  • bladder control (if needed)

• surgical

  • goal

    • decompression

    • pain relief

    • axonal regeneration

  • laminectomy + discectomy

  • distraction and stabilization

• prognosis and outcome

  • laminectomy and discectomy

    • 70-80% success rate

• best surgical outcome

  • mild disease

  • 50% success rate with severe neurologic signs

• recurrence

  • new bone formation

  • scar tissue formation

wobbler syndrome

• cervical malformation or cervical protrusion →

  • compression of spinal cord / nerve roots →

  • pain and neurologic deficits

• vertebral canal is proportionally smaller

• dynamic and static disease

  • disc-associated vs osseous-associated compression

Disc-associated wobbler syndrome

• middle-aged, large breed dog

  • Doberman pinscher*

• vertebral canal stenosis (C5-6,6-7)

• torsion of the caudal cervical

• intervertebral disc protrusion

• ligamentum flavum hypertrophy

osseous associated wobbler syndrome

• young, giant breed, 9 ½ months old

  • Great Dane*

• ligamentum flavum hypertrophy

• vertebral canal stenosis due to:

  • proliferation of the vertebral arch

  • articular process proliferation

  • pedicle proliferation

clinical presentation for wobbler syndrome

• Chronic, progressive (weeks to months)*

• acute presentation - neck pain

• mild to moderate proprioceptive deficits / ataxia, lameness

• signalment

  • large breed (3+ years, mean age 7 years)

    • 50% single site / 50% multiple sites

    • C6-7 most common

  • giant breed (9mo-2 years)

    • 20% single site / 80% multiple sites

    • C6-7 most common

• diagnosis

  • radiographs - limited information not helpful

  • CT -better for bone

    • traditional method

    • identify direction of compression

  • MRI * soft tissue better

    • gold standard

      • more accurate at identifying site, severity, nature of compression

      • assessment of spinal cord parenchyma

      • sometimes have to do MRI and CT

treatment for wobbler syndrome

• medical

  • reserved for mildly affected cases

  • exercise restriction

  • harness instead of neck load*

  • pain medications - gabapentin, NSAID

  • good footing, padded bedding

  • success

    • 54% improved; 27% unchanged neurologically

    • clinical signs improved or stable - 81%

• surgical

  • indications

    • more severe neurologic signs and pain

    • lack of response to medical management

    • short and long-term expectation of owner

    • presence of concurrent problems

  • success

    • improvement in 81%of cases

techniques for wobbler syndrome and prognosis

• direct decompression: static lesions

  • ventral slot

  • dorsal laminectomy

• distraction - stabilization: dynamic lesions

  • decompress disc protrusion

  • stabilize disc space with spacer / implants

• neurologic deterioration

  • most significant with a continuous laminectomy (70%)

• domino effect

  • adjacent segment syndrome (20%)

  • mainly with distraction - stabilization techniques

  • altered biomechanics at operated sited leads to stress/load at adjacent site

• up to ~80% improvement

• risk of recurrence -25%

Atlantoaxial instability

• compression and concussion of cranial cervical spinal cords

• displacement of vertebrae into spinal canal

• C2 dorsally displaced from C1

• due to:

  • ligamentous instability

  • osseous abnormality

• congenital or traumatic

• effect:

  • excessive flexion of the A-A joint

  • cranial axis displaces dorsally in relation to atlas

• abnormalities

  • aplasia of the dens - 46%

  • hypoplasia of the dens - 34%

  • dorsal dens angulation

  • separation of the dens

  • ligamentous instability

• up to 24% of dogs with A-A instability have an normal dens

clinical presentation for atlantoaxial instability

• young, small breed dogs (<1 year)

  • toy poodle

  • yorkshire terrier

  • chihuahua

• severity of signs is dependent on degree of spinal cord injury

• clinical signs

  • neck pain

    • most traumatic

    • 30-60% congenital

  • neurologic deficits (94% of patients)

    • progressive tetraparesis ataxia

diagnosis for atlantoaxial instability

• physical examination: Do not flex the neck! makes C2 go dorsally and makes pain worse in flexion of neck

• radiographs

  • increased distance between dorsal arch of C1 and dorsal spinous process of C2

• CT

• MRI

• differential diagnosis

  • meningitis

  • syringomyelia

  • discospondylitis

  • disc disease

Treatment for atlantoaxial instability

• Medical

  • goal: stabilize joint while ligamentous structures heal

  • candidates

    • acute onset of clinical signs without prior history

    • young dog with immature bone

    • financial constraints

  • strict confinement: 6-8 weeks * very important

  • neck brace*

  • pain medications

  • Gabapentin, NSAID

  • good long term outcome

• surgical

  • gold standard

  • goal

    • reduce further compression of the spinal cord

    • definitive stabilization of the A-A joint (fusion)

  • complication rate: 50-70%

• prognosis

  • medical management

    • good long term prognosis in 40% of cases

    • better if clinical signs <30days

  • perioperative mortality - 10-30%

principles of integumentary system surgery

• tissue trauma

  • scalpel < scissors < CO2 < electroscalpel

  • skin hooks or suture stays < tissue forceps or repeated tissue manipulation

• to decrease the risk of devascularization

  • dissect deep to the subdermal plexus

    • under cutaneous muscles or the deep dermal layer

skin closure

• primary

  • immediate direct closure

• delayed primary (<3-5 days)

  • delayed direct closure before onset of granulation tissue

• secondary (>3-5 days)

  • delayed direct closure after onset of granulation tissue

• second intention

  • indirect closure by onset of granulation tissue and epithelization

technique chosen for skin closure depends on

• elasticity of surrounding tissue

• location of the defect

• size of defect

• regional blood supply

• wound healing factors - systemic and local

• simple is best

skin tension

• tension lines are formed by the predominant pull of fibrous tissue within the skin

• tension increases the risk of closure complications

• generally close skin parallel to tension lines

• if closed perpendicular to skin tension lines:

  • delays in healing

  • wider scar

  • more tension - dehiscence, pain

  • dog ears

Tension relief - Undermining

• separate the skin and panniculus muscle (when present) from underlying subcutaneous tissue

  • blunt and sharp scissor dissection

• simplest technique to relieve tension

• maximizes elastic potential of skin edges

• undermining - delayed wound closure

  • separate granulation tissue from epithelium

  • caution!! dont get too aggressive

Tension relief - walking sutures

• must do undermining first

• moves skin across a defect

• obliterates dead space

• distributes tension over the wound surface

  • via several suture rows

  • less chance of dehiscence of main incision closure

• stretches skin in small increments

• anchored in fascia and dermis

  • do not penetrate the skin surface

tension relief - suture patterns

• cruciate

• horizontal mattress

• vertical mattress

• far-near-near-far

• help prevent sutures from cutting out

• provides limited tension relief

• can place sutures farther from skin edge or use suture pattern to help disperse pressure

  • cruciate - in skin

  • horizontal / vertical mattress - in fascia/deep tissue

  • far-near-near-far

• stents and quills

• skin stretching

Dog ears

• puckers of skin at the end of the incision line

• correction via various methods

  • outline with an elliptical incision, remove redundant skin, appose skin edges

  • cut off the dog ear - blade or scissors

irregular circular skin defects

• difficult to close because of dog ears

• perform a linear closure

  • easier with smaller defects

  • close parallel with line of tension

  • * start in the center of the wound

  • correct the dog ears

• convert to ellipse

  • easier with smaller defects as well

    • resects more skin than necessary

  • 4:1 length to width ratio

  • eliminates dog ears

  • adequate surgical preparation

• combined V - good with lesion by eye

  • 45 degrees from axis of tension

  • additional skin is not removed

triangular defects in skin

• Y closure

  • start at points of triangle and suture towards center

  • place horizontal type suture in center (where most tension is)

• rotational flaps

  • semicircular / three quarter circular flap of skin rotated at a pivot point into the defect

  • single

    • used when skin is available only on one side of the defect or rotation of skin results in a defect/distortion of adjacent structures

  • bilateral

    • little skin is available on both sides of defect

  • 4:1 length to width - prevent tension

irregular skin defects

• square or rectangle

  • start at corners and work inward

    • skin must be available on all four sides of defect

  • advancement flaps

fusiform (elliptical) skin defects

• place suture across widest part of defect (center)

• divide each remaining segment in half with subsequent sutures

crescentic skin defects

• one side is longer than the other

• close beginning at the midpoint

• each remaining segment closed by dividing segments in half

• place sutures on concave side closer, further on convex side

skin grafts

• transfer of a segment of free dermis and epidermis to a distant recipient site

• full thickness (recommended)*

  • epidermis and dermis

• partial thickness

  • epidermis and variable dermis - part

  • cannot do in cats (too thin)

• types

  • sheet or mesh (often preferred)

  • punch, stamp, stripe

    • mesh preferred b/c

      • increased surface area

      • better conformity

      • fluid drainage

• factors critical to graft survival

  • healthy vascular bed - no infection

  • lack of motion

  • contact between the bed and graft

  • lack of infection

Neoplastic masses

• wide excision

• submit tissue for histopathologic margins

• first attempt at removal is the best attempt

• exact margin depends on tumor type

  • lipoma - 0cm

  • mast cell tumor - 1-2cm

  • high grade sarcoma - 3cm

vulvar fold redundant skin

• signalment

  • overweight dogs

  • younger dogs with an infantile, recessed vulva * most commonly seen

• superficial dermatitis, urinary incontinence, recurrent urinary tract infections

• episioplasty

redundant tail folds

• signalment

  • Brachycephalic

  • bulldog, Schipperke, Manx cat

• screw tail, corkscrew tail, ingrown tail

• redundant skin overlaps a deformed terminal caudal vertebrae

• tail fold pyoderma secondary complication

• en-bloc resection of skin and deformed tail

pinna lacerations

• lacerations

  • skin

  • skin + cartilage

  • skin + cartilage + skin

• use auricular cartilage as a template

• partial thickness may be treated conservatively

• marginal defects may be amputated

Pinna aural hematoma

• collection of blood, serum, or both in the pinna

• forms second degree longitudinal planar fracture of articular cartilage

• exacerbated with shaking of the head

• numerous techniques for repair

  • goal: obliterate dead space

  • incision and suture, CO2 laser

  • infusion of steroid

• common with ear infections shaking head

lateral ear canal resection for otitis externa / media

• removes the lateral wall of the vertical ear canal

• new opening is at junction of vertical and horizontal canal

• indications

  • adjunct to medical management for otitis externa

  • minimal hyperplasia of ear canal

  • small neoplastic lesions of lateral aspect of vertical canal

• allows for increased drainage, aeration of canal, facilitates medication administration

• owner beware - must still medicate the ear

• not for concurrent otitis media or obstruction of the horizontal ear canal

vertical ear canal resection for otitis externa / media

• indicated for vertical canal disease

  • tumor infiltrating vertical canal

  • otitis externa confined to the vertical ear canal

• horizontal canal must be normal

• better cosmetic appearance than with lateral resection when abundant hyperplastic tissue is present in and around vertical ear canal

total ear canal ablation (TECA) for otitis externa / media

• most commonly performed

• indications

  • chronic otitis externa

    • failure of medical management

  • ossification, hyperplasia of entire canal

  • neoplasia

• must perform a lateral bulla osteotomy ( scraping of)

  • must remove all epithelium in bulla

ventral bulla osteotomy otitis media

• allows increased exposure to tympanic cavity

• technique of choice for cats with:

  • neoplasia

  • nasopharyngeal polyps

• better drainage of bulla

• cats have two compartments that make up their bulla

Caudectomy

• amputation of a portion / all of the tail

• therapeutic caudectomy

  • traumatic lesions, infection, neoplasia

• cosmetic caudectomy - puppies

  • 3-5 days of age

  • analgesia - usually local

• adult caudectomy

  • general anesthesia

  • V-shaped incision, vessel ligation, tension free closure

onychectomy

• cats

• removal of the 3rd digital phalanx (P3)

  • complication rate ~20%

• elective - usually performed between 3-12 mo

  • young tolerate the procedure better than old

• front or all four limbs educate owners

• alternatives : nail trim, caps, outdoor cat

• surgical procedure

  • local / ring block to provide additional analgesia

  • place a tourniquet

    • radial neuropathy

      • limit time

  • scalpel

    • all of P3 is removed by surgical dissection

  • resco nail clipper

    • better chance of leaving ungual crest

    • can get persistent pain/lameness from remaining bone

  • CO2 laser

    • less bleeding

    • faster healing

    • smaller incision

    • disadvantage; laser is expensive

• sutures

  • absorbable, monofilament

  • single for skin apposition

• postoperative care

  • bandages x 24 hours

  • paper litter

• complications

  • hemorrhage, infection

  • claw re-growth, lameness from remaining bone

  • pad injury, tissue necrosis

onychectomy for dogs - Neuter

• indications

  • trauma

  • tumor - SCC, melanoma, sarcoma

  • infection