Surgery Flashcards
1
Q
Define cholesteatoma.
A
An epidermoid cyst within the middle ear
2
Q
Define myringotomy.
A
Making a hole in a membrane, like the tympanic membrane
3
Q
Define neuropraxia.
A
Injury to a peripheral nerve
4
Q
How is the structure of the ear all connected?
A
- EEC is made up of vertical and horizontal canals
- EEC is connected to ME via EAM, which is where ear drum sits
- ME is where the bulla and ossicles (tiny bones that conduct sound waves from EEC)
- ME connected to pharynx via auditory tube
- ME is connected to IE which sound waves connect to cochlea via cochlea window
- Another window in the IE called vestibular window that connects to vestibular apparatus
- IE connected to the brain via cochlea and vestibular nerves
5
Q
What are the causes and site of autoimmune ear diseases?
A
Allergic skin disease
Discoid lupus erythematosus
Pemphigus
External ear canal, pinna
6
Q
What are the primary anatomical causes of ear diseases?
A
Congenital ear canal stenosis
Pendulous ears
Hair ear canals
7
Q
What are the secondary anatomical causes of ear diseases?
A
Secondary ear canal stenosis
Cauliflower ear
Other traumatic deformity
8
Q
What are the sites of anatomical ear diseases?
A
Pinna – post injury. Puncture/laceration/aural haematoma
External ear canal – commonly secondary changes due to scarring with chronic otitis externa, which is usually due to underlying allergic skin disease
9
Q
What are the neoplastic causes of ear disease?
A
Benign – ceruminous gland adenomas, papillomas, inflammatory polyps
Malignant – squamous cell carcinoma, ceruminous gland adenocarcinoma
10
Q
What are the sites of neoplasia causing ear disease?
A
Pinna, external ear canal, middle ear, inner ear, para-aural
11
Q
What are the infectious causes of ear disease?
A
Bacterial – staphylococcus, streptococcus, pseudomonas
Parasitic – mites (otodectes, demodex, sarcoptes, harvest mites)
Fungal – Malassezia, ringworm
12
Q
What are the causes and sites of inflammatory ear disease?
A
Cholesteatoma
Foreign bodies
Inflammatory polyps
Solar dermatitis
Viral (distemper)
Pinna, external ear canal, middle ear, inner ear, para-aural
13
Q
What are the causes and sites of traumatic ear disease?
A
Self-inflicted secondary to pruritic
Surgical
Accident
Fighting
Pinna, external ear canal
14
Q
What is ear canal avulsion and what is the consequence of this?
A
Separation between the auricular and annular cartilage or at the level of the external acoustic meatus. Fluid, cerumen and debris will accumulate in the proximal portion of the ear canal. Likely to become infected causing a para-aural abscess.
15
Q
Where are inflammatory polyps found?
A
Auditory tube, external ear canal, middle ear, nasopharynx
16
Q
What are the possible causes of aural haematomas?
A
Trauma
Immune-mediated or coagulopathy
17
Q
What are the clinical signs of aural haematomas?
A
Head shaking
Ear scratching
With/without underlying dermatopathy
With/without trauma
Pain
Swollen pinna
Reason for pruritus
18
Q
What factors may determine whether an aural haematoma is medically or surgically treated?
A
- Haematoma size and how long has it been there
- Patient co-morbidities
- Patient temperament
- Owner finances
- Owner practicalities
- Surgeon preference
- Cosmetic appearance
19
Q
How are aural haematomas surgically treated?
A
- Skin incision – position and length depends on where on the pinna the haematoma is
- Evacuate – flush with saline to remove fibrinous material that will prevent the medial skin and cartilage coming into close apposition
- Bring incision edges together – the medial skin will be stretched so there will be excess skin. So start right by/close to your incision and work laterally or you will end up with a raised bit of skin in the middle.
- Sutures to close dead space
20
Q
Where is a lateral wall resection done?
A
Disease isolated to vertical ear canal’s lateral wall
21
Q
How is a lateral wall resection done?
A
- Surgical preparation
- Incision - U shaped over later ear canal, with U ventral to level of horizontal canal
- Expose lateral wall of vertical canal
- 2 parallel cartilage incisions
- Remove excess cartilage and its overlying skin to leave a 2-3cm drainage board, ventral to the opening to the horizontal canal. Board must not obstruct the opening
- Close
22
Q
Where is a vertical ear canal ablation done?
A
Disease isolated to vertical ear canal. Taking both lateral and medial wall of the ear canal and leaving the horizontal behind.
23
Q
How is a vertical ear canal ablation done?
A
- Surgical preparation
- Skin incision – T-shaped incisions that extends below level of horizontal canal
- Expose the vertical canal
- 2 cartilage incisions to create a dorsal and ventral flap from the residual vertical canal – 1 incision cranially and the other caudally
- Close – reflect the dorsal and ventral cartilage flaps into place
24
Q
Where is a total ear canal ablation and lateral bulla osteotomy done?
A
Taking horizontal and vertical ear canals and taking lateral wall of the bulla
25
How is a total ear canal ablation and lateral bulla osteotomy?
1. Skin incision – T-shaped incisions that extends below level of horizontal canal, around the inside of the pinna to include the whole opening to the vertical ear canal.
2. Exposure the vertical canal
3. Perform a lateral bulla osteotomy
26
When is a ventral bulla osteotomy done?
When external ear canal is unaffected and/or disease is confined to the middle ear or if has had external ear canal surgery but residual disease in bulla.
27
What are the reasons for a pinnectomy?
- Neoplasia - curative or palliative
- Neutering status – feral cats
- Trauma – if very severe damage
28
How is a pinnectomy done?
1. Excise tip
2. Undermine the lateral skin with/without excise a further 2mm cartilage
3. Find a tissue plane between skin and cartilage
4. Elevate the lateral skin enough to allow it come over the top of the cartilage
5. Suture skin closed medially
29
What are the possible complications of ear surgery?
- Failure to cure
- Healing tissue
- Anatomical complication
- Infection
- Haemorrhage
- Neurological complication
30
When might ear surgery cause failure to cure? How is this treated?
Wrong procedure
Neoplasia
Treatment – more surgery, palliation
31
When might healing tissue be problematic after ear surgery? How is this treated?
- Residual infected tissue causing para-aural abscess
- Residual cartilage
- Patient interference
- Poor technique
Treatment – conservative management or more surgery
32
What are the possible anatomical complications of ear surgery and how is this treated?
- Cauliflower ear
- Stenosis
- Traumatic ear canal avulsion causing para-aural abscess
Treatment – conservative management or more surgery
33
When might ear surgery cause infection and how is this treated?
- Recurrence of primary condition
- Secondary infection
Treatment – culture and targeted antibiosis, more surgery
34
When might ear surgery cause haemorrhage and how is this treated?
- External to ear canal – branches of jugular and carotid
- Within bulla – retroglenoid vein
Treatment – avoid, ligatures, electrosurgery, pressure, bone wax
35
What are the consequences of neurological complications of ear surgery?
Temporary neuropraxia or permanent dysfunction
Externally vulnerable branches of cranial nerves – facial nerve runs around horizontal canal from caudal to cranial
Internal branches of cranial nerves
- Sympathetic branches within middle ear > Horner’s syndrome
- Vestibular nerves > balance issues
- Cochlear nerves > hearing issues
36
How are neurological complications from ear surgery treated?
Conservative management, more surgery, palliation
37
Define an pharyngeal mucocele.
Salivary mucocele within the pharynx formed due to damage to mandibular or parotid salivary ducts
38
Define ranula.
Salivary mucocele under the tongue formed due to damage to mandibular or sublingual salivary ducts
39
Define sialography.
Contrast radiography of salivary ducts
40
Define sialoliths.
Stones formed within salivary glands/saliva
41
Define subcutaneous emphysema.
Free air under the skin
42
Define trichobezoar.
Furball
43
When approaching the neck surgically, where are the important anatomical landmarks in this region?
- Muscles = combined sternohyoideus and sternothyroideus
- Oesophagus = dorsal to the trachea and just to the left of midline
- Larynx = cranial, midline and palpable
- Trachea = caudal to larynx, midline and palpable
- Recurrent laryngeal nerves = run from thorax to larynx either side of trachea
- Thyroids and parathyroid glands = caudal to the larynx, either side of trachea
44
What is the aetiology of stick injuries?
- History of playing with sticks
- Owner aware or unaware
45
What are the oropharyngeal clinical signs of peracute stick injuries?
- Severe impaling injury
- Severe haemorrhage
- Dyspnoea due to pneumomediastinum/pneumothorax
46
What are the oropharyngeal clinical signs of acute stick injuries?
- Nothing
- Pain – one yelp, pain opening mouth
- Pawing at mouth, gagging, retching, dysphagia
- Ptyalism/hypersalivation with/without blood
47
What are the systemic clinical signs of acute stick injuries?
Depression
Pyrexia
48
What are the oropharyngeal clinical signs of chronic stick injuries?
- Worsening of the acute signs
- Swelling
- Draining tract
- Inflammation/abscessation associated with a foreign body. Not all FBs will introduce an infection and some infections can be worse than others (antibiotic stewardship)
49
How are oral examinations used to diagnose stick injuries?
- Conscious > limited
- Sedation > rarely a good idea unless confident FB is in the oral cavity only, not further back and is stuck rather than penetrating
- GA safer – have control of the airway
50
Which imaging modalities can be used to diagnose stick injuries?
Laryngoscope/oesophagoscopy
Radiographs
Ultrasonography
CT - best for iceberg injuries
51
How are patients with stick injuries stabilised?
- IVFT if hypovolaemic or shocked
- Pain relief – opioids initially rather than NSAIDs
- Antibiotics
52
When is surgical exploration done with stick injuries?
- If unable to retrieve pieces
- If acute with signs of cervical emphysema/dyspnoea
- If chronic stick injury
53
Outline stick injury surgeries.
1. Follow the tract
2. Need a larger incision than you might suspect
3. Culture and histopathology
4. Debride and flush
5. Close
54
Why is debridement and flushing important in stick injury surgery?
- Microscopic FBs can be present
- Necrotic tissue will make it difficult to clear infection and be a cause of ongoing draining sinus tract without foreign material
55
What is the post-op management for stick injury surgery?
Analgesia
IVFT
Antibiotics
56
What is the prognosis of acute and chronic stick injury surgeries?
Acute – best handled definitively at time of presentation so no residual foreign material, repair damage as required
Chronic – pre-treatment can complicate investigation, particularly antibiotics (resistance an issue), best to explore when actively draining
57
Where does the cervical oesophagus sit in relation to the trachea?
Dorsal and to the left
58
What are the clinical signs of cervical oesophageal foreign bodies?
Gagging
Dysphagia
Retching
Regurgitation
Vomiting
Dyspnoea
59
What are the common sites of cervical oesophageal foreign bodies?
Heart base
Distal oesophageal sphincter
Near the diaphragm
60
How can cervical oesophageal foreign bodies be diagnosed with imaging?
- Radiographs – may need contrast to highlight radiolucent FBs, plain radiography may not identify perforations, avoid barium in case there is a perforation
- Ultrasound
- CT
- Fluoroscopy
- Endoscopy - ideal, allows for easier, safer less traumatic removal, assessment of damage
61
How can oesophageal foreign bodies be retrieved non-surgically?
Oesophageal foreign body forceps – blind retrieval, can be traumatic, bring foreign body out of mouth if can be done with minimal trauma.
Can use a Foley catheter pushed beyond the FB and bulb inflated and advance into stomach
62
Outline surgical retrieval of cervical oesophageal foreign bodies?
- Ventral, midline skin incision
- Split the paired strap muscles
- Avoid damage to neurovascular/thyroids
- Gentle retractors to expose
- Longitudinal incision following the oesophageal striations
- They have no serosal layer means that dehiscence is more likely than for small intestinal surgery
63
What are the possible complications of surgical retrieval oesophageal foreign bodies?
- Oesophagitis
- Oesophageal perforation – sharp edged FBs
- Oesophageal necrosis
- Mediastinitis/pneumomediastinum – fascial planes of the neck communicate with the mediastinum
- Aspiration pneumonia secondary to dysphagia
64
How is oesophagitis from surgical oesophageal foreign body removal treated?
Mild = antacids/Sucralfate
Severe = feeding tube
65
How does oesophageal necrosis form from surgical oesophageal foreign body removal?
- Severe oesophagitis > inflammatory necrosis
- Delayed diagnosis > pressure necrosis
- Necrosis can be partial or full thickness
- May lead to late breakdown > perforation
- May lead to stricture formation
66
If cost if not an issue, what is the best imaging modality for penetrating stick injury?
CT
67
How do salivary mucoceles form?
- Salivary duct leakage – idiopathic, trauma, sialoliths
- Inflammation – salivary gland, ducts and oral mucosa all adapted to contact with saliva, marked response to the saliva being in the subcutaneous tissues, a form of autodigestion
68
What are the clinical signs of salivary mucoceles?
Localised swelling in subcutaneous or submucosal tissues:
- Pharyngeal swelling – respiratory distress, dysphagia
- Sublingual ranula causes a saliva-filled, cyst-like swelling under the tongue
- Zygomatic can cause proptosis
69
How are salivary mucoceles diagnosed?
- Aspiration – characteristic stringy fluid, low cell numbers
- Imaging
- Glands involved
70
How are salivary mucoceles treated?
Salivary drainage
- Reasonable for traumatic mucoceles
- Futile as saliva will continue to form
- Marsupialisation for ranula is a possibility as can get the leaking saliva to drain into the mouth
Gland removal
70
What does the position of mucoceles suggest?
- Cervical = sublingual or mandibular
- Pharyngeal = mandibular
- Ranula = sublingual
- Under eye = zygomatic
- Base of ear/side of head = parotid
- Mandibular/sublingual most common
71
How can marsupialisation treat salivary mucocele?
- Incise the ranula and suture the inner aspect to the outer mucosal layer of the tongue
- Saliva drains into the mouth directly
72
What are the complications of surgical treatment of salivary mucoceles?
Iatrogenic damage
Seroma formation
Infection
Recurrence
73
Which salivary gland is most commonly affected by a salivary mucocele and where does the mucocele sit?
Mandibular, cervical
74
What are the differential diagnoses of neck masses?
- Foreign body-induced abscess or sinus tract
- Salivary mucoceles
- Oesophageal foreign body
- Thyroid and parathyroid diseases
- Neoplasia (skin, subcutaneous)
- Congenital neck cysts
- Lymphadenopathy
- Cervical expanding hematoma
- Postoperative seroma
75
Distinguish stertor and stridor.
Stertor = abnormal. Low breathing noise created above the level of the larynx
Stridor = abnormal, high-pitched noise, typically created within the larynx or below
76
Define oronasal fistulae.
Abnormal communication between the oral and nasal cavities
77
What is the aetiology of oronasal fistulae?
- Congenital – cleft lip/palate
- Acquired
- Breed disposition – brachycephalic dogs and cats
78
What are the clinical signs of oronasal fistulae?
- Facial deformity
- Coughing/gagging when drinking water
- Pneumonia due to aspiration
- Failure to thrive – not getting enough nutrition due to difficulties swallowing
- None
79
Distinguish primary and secondary palate defects.
Primary – upper lip, rostral part of the maxilla, maxillary alveolus, and the hard palate rostral to the incisive foramen
Secondary – more distal hard palate behind the incisive foramen and soft palate
80
What is causes by congenital oronasal fistulae?
1. Inability to suck
2. Milk into the nasal cavity
3. Milk into trachea and out of nose
81
What may cause oronasal fistulae?
- Hereditary
- Nutritional – deficiency during pregnancy
- Viral – drugs and other chemical exposure during pregnancy, teratogen
- Trauma
82
When should treatment of oronasal fistulae be treated?
Delay surgery until 3-4 months old
83
How are oronasal fistulae surgically treated?
Reconstruct tissues to form a more normal barrier between oral and nasal cavities. Tissue from the mucosa side of the lip to cover hole instead of tissue from the hard palate.
84
What are the possible causes of acquired oronasal fistulae?
Trauma – RTA, malicious act, dental or oral procedure/elevator handling
Periodontal disease – severe localised inflammation/infection causing osteomyelitis, particularly in Dachshunds
85
What is the supportive care for acquired oronasal fistulae?
- Adjust feeding – small sized kibble
- Analgesia
- Oral rinses to avoid secondary infection
- Systemic antibiotics best avoided
- Feeding tube to bypass the area so food stuff doesn’t interfere with healing
- Avoid chewy treats and toys
86
What are the possible complications of oronasal fistulae surgical treatment?
Dehiscence – high failure rates >50%
Repeat surgery
- Friable tissue
- More debridement
- Less and less tissue available
- Progressively harder to get a good outcome
87
What is the most common reason for a puppy to be born with a congenital cleft palate?
Inherited a faulty gene from parents
88
Name 3 nasopharyngeal disorders.
Nasopharyngeal atresia/stenosis
Nasopharyngeal/BOAS
Nasopharyngeal polyps
89
What is the aetiology of nasopharyngeal atresia/stenosis?
Congenital or acquired. Secondary to severe inflammation – rhinitis, foreign body, reflux under GA (silently regurgitating in GA and stomach acid sits in oesophagus or nasopharynx and causes bad inflammation that causes stenosis)
90
What are the clinical signs of nasopharyngeal polyps?
Clinical signs will depend on where they pop out from forming in the middle ear
91
What is the conservative treatment for nasopharyngeal polyps?
- Traction – grasp polyp with forceps. Apply gradual, steady traction pressure gently, some are very friable
- Steroids – prednisolone
92
What is the surgical treatment for nasopharyngeal polyps?
VBO or ear canal surgery
93
What are the complications of traction for treatment of nasopharyngeal polyps?
- Bleeding usually self-limiting
- Neurological signs
- Infection
- Recurrence
94
An apparently 10 day old Persian kitten is presenting with milk coming out of its nose. What is the most likely diagnosis?
Secondary palate deficit
95
What are the clinical signs of nasopharyngeal disorders?
Upper respiratory obstruction
Stertor
Mouth breathing
Sneezing
96
What tissues can be affected by oral masses?
Bone – mandible, maxilla, hard palate, nasal bones
Soft – gingiva, mucosa, periodontal ligament, tongue, tonsils
97
What are the clinical signs of oral masses?
- Mass
- Dysphagia – gagging, messy eating, rubbing at mouth when food lodged uncomfortably
- Halitosis
- Bleeding
98
How are oral masses investigated?
- Cytology - impression smear/scrapings/FNA. SCC can be friable so smears/scrapings may be helpful
- Histopathology
- Staging
99
What are the treatment options for oral masses?
- Local – for benign masses
- Wide - getting more than 1cm margin likely to be very challenging with a malignancy with/without bone depending on cell type and site
- Lymph node – if local metastasis present, particularly important for melanoma
- Melanoma vaccine
- Radiation
- Chemotherapy
- Photodynamic therapy
100
What are the possible intraoperative complications of oral mass surgery?
Bleeding
Nerve damage
Fracture
Damage to salivary ducts
101
What are the short term post-operative complications of oral mass surgery?
Dysphagia, drooling, inappetence
Dehiscence
Swelling
102
What are the long term post-operative complications of oral mass surgery?
Recurrence
Metastasis
Anorexia
Fistulation
Malocclusion, ulceration
Chronic pain
Mandibular drift
103
What is the best treatment option for a nasopharyngeal inflammatory polyp?
Traction followed by steroids
104
How are patients with oral cavity trauma triaged?
- Treat shock
- Pain relief
- With/without antibiotics if infection present
- Preliminary clinical exam to assess severity of injuries
105
What is done to manage patients with oral cavity trauma post stabilisation?
- Complete clinical exam to check for other external/internal injuries
- Check for co-morbidities that could complicate healing
- Imaging
- Wound management
106
What are in the indications for a glossectomy?
- Trauma – bites, laceration, burn
- Neoplasia
- Lingual abscess
107
What are the complications of glossectomy?
- Haemorrhage – intra or post operative
- Failure to cure – recurrence
- Failure to heal – dehiscence, tongue necrosis
- Tongue function
108
What are the consequences of impaired tongue function as a complication of glossectomy?
- Dysphagia/ptyalism = aspiration pneumonia
- Prehension = messy eating and drinking
- Grooming = poor coat care
- Panting = heat stress
109
What are the indications for a tonsillectomy?
BOAS or neoplasia
110
What is the technique for a tonsillectomy?
- Grasp the tonsil firmly
- Exteriorise tonsil from crypt
- Electrosurgery/sutures to prevent bleeding from the tonsillar vessels
- Transect at base
- Close tonsillar crypt with simple continuous suture pattern to reduce bleeding
111
What are the complications of a tonsillectomy?
- Intra-operative/post-operative haemorrhage
- Failure to cure/recurrence
112
How would you confirm your diagnosis of a nasopharyngeal polyp?
Otoscope and endoscopy
113
Which plain radiographic views of the skull would be most helpful for diagnosing nasopharyngeal polyps?
Open mouthed, rostro-caudal – as there is so much bone in the skull so only view, MRI and CT are better for visualising the head. Sould be soft tissue density in the middle ear and if not there is something in there.
114
What is the most common complications following treatment with traction alone with nasopharyngeal polyps?
Polyp regrowth
115
What are the most common complications following treatment with traction and VBO for nasopharyngeal polyps?
Horner’s syndrome and vestibular disturbances
116
What are the possible complications after a partial maxillectomy?
Difficulty eating
Wound dehiscence
Altered appearance
Buccal ulcer
Chronic pain
117
How do complications after maxillectomy differ from complications following mandibulectomy?
Potential penetration of the nasal cavity performing max – formation of oronasal fistula. Cosmetic appearance with mandibulectomy. More issues with post op inappetence with maxillectomy and more chronic pain associated with maxillectomy. Cosmetic results following maxillectomy and mandibulectomy vary between location.
118
Define phaeochromocytoma.
Malignant adrenal tumour that secretes catecholamines
119
What are the possible splenic conditions?
- Generalised splenic enlargement
- Splenic mass with/without
- Splenic torsion – with or without GDV
- Splenic trauma
120
How are splenectomy for splenic masses done?
- Partial vs total splenectomy
- Exteriorise the spleen by pushing the abdominal wall out so spleen ‘spills’ rather than risking rupture
- Assistant to hold the weight of the mass during splenectomy
- Suction to avoid abdominal contamination with neoplastic cells
- Histopathology
121
What is the splenic hilar technique to close vessels in a splenectomy?
Very safe, will not disturb blood supply to pancreas or stomach
122
What is the en masse ligation technique to close vessels in a splenectomy?
Quicker than hilar but need to be able to identify:
- Splenic artery must ligate distal to the pancreatic artery
- Left gastroepiploic artery
- Short gastric arteries
123
What must be done if a splenectomy is being performed as part of GDV?
Preserve all blood supply to the stomach
124
What are the post-splenectomy complications?
- Haemorrhage
- Pancreatitis
- Immunosuppression
- Arrythmias – ventricular ectopic beats or ventricular premature complexes, do not treat unless causing a clinical problem with lidocaine
125
What is the prognosis of haemangiosarcoma?
10 weeks
126
What are the clinical signs of adrenal gland disease?
- None – incidentaloma
- Secondary effects by excess production of aldosterone, cortisol, androgen, catecholamines (epinephrine, norepinephrine)
- Haemoabdomen – some adrenal masses will present with spontaneous bleeding causing retroperitoneal swelling or haemoabdomen
127
What is the prognosis of adrenalectomies?
- Very challenging anaesthesia, surgery and aftercare
- Some will die from blood loss on the table, some will develop thromboembolism post-operatively
- Short and long term post-op can be very challenging
128
When performing a splenectomy for a splenic mass using the en mass technique which 2 arteries do you need to preserve?
Pancreatic and left gastroepiploic artery
129
What is characteristic of cats with pancreatitis?
Yellow
130
What are the indications for pancreatic surgery?
- Endocrine pancreatic neoplasia
- Exocrine pancreatic neoplasia
- Necrotising pancreatitis
- Pancreatic abscessation
- Pancreatic cysts
131
What are the possible pancreatic surgical options?
- Partial pancreatectomy of affected area, identified on imaging
- Omentalisation a good idea, can be packed into pancreatic cysts and abscesses
132
How much of the pancreas can be resected in partial pancreatectomies?
Up to 80%
133
What are the characteristics of insulinomas?
- Malignant carcinoma
- Hypoglycaemia in an upright dog is the big clue, so brought in for very vague reasons – lethargy, exercise intolerance
- Metastasis to LN and liver
134
What are the post-operative considerations of insulinomas?
- Micro-metastasis can result in persistent hypoglycaemia post-operatively
- Can develop DM
135
What are the clinical signs of exocrine pancreatic neoplasia?
Vomiting
Weight loss
Difficult to differentiate from pancreatitis
136
How is exocrine pancreatic neoplasia managed?
Very poor prognosis so unlikely to be surgical = palliation
137
What are the partial pancreatectomy options?
Biopsy techniques similar to liver:
- Guillotine using absorbable monofilament suture
- Finger fracture
138
Describe the position of the thyroid glands in cats and dogs.
5th and 8th tracheal rings. Lie ventrolateral to the trachea. R gland typically slightly more cranial than left
139
What are the differences between the functionality of thyroid surgical conditions in cats and dogs?
Almost all feline thyroid masses will be functional and present due to hyperthyroidism
Almost all canine thyroid masses will be non-functional and present due to the mass
140
How is malignant thyroid neoplasia staged?
- Local extent of disease - FNA and biopsy may carry high risk of haemorrhage
- Local lymph nodes
- Distant metastasis
141
What may affect the bilateral disease incidence of the thyroid gland?
Presence of an isthmus
142
How is a canine thyroidectomy done?
1. Dorsal recumbency
2. Ventral midline approach to the neck
3. Dissect between muscles of the neck
4. Unilateral or bilateral thyroidectomy
5. With/without parathyroidectomy
6. Avoid iatrogenic damage to the blood vessels, nerves and other anatomical structures close by
7. Decide before surgery whether to do unilateral/bilateral and whether to include the parathyroid
143
What are the options for thyroidectomy?
Extracapsular – easiest. Ligate vessels and remove thyroid and parathyroid glands in total. For tumours only, avoid this for hyperthyroidism – don’t want to remove parathyroid gland due to risk hypocalcaemia
Intracapsular – challenging, more likely to leave thyroid tissue behind
Modified intracapsular – try to preserve parathyroid but more fiddly
Modified extra capsular – best, leave a bit of capsule so preserve parathyroids
144
What are the possible complications of thyroidectomies?
- Haemorrhage
- Seroma
- Laryngeal paralysis – if damage recurrent laryngeal nerves
- Post op hypocalcaemia
- Recurrence
145
When is recurrence of thyroidectomy more likely?
With ectopic tissue, intracapsular technique and malignant neoplasia
146
Describe unilateral modified extracapsular thyroidectomy before and after the procedure.
Normal thyroid:
- Pre-op = smaller, decreased T4, normal PTH
- Post-op = increasing T4, normal PTH
Overactive thyroid:
- Pre-op = increased size, increased T4, normal PTH
- Post-op = zero T4, reduced PTH
147
What is the characteristic of bilateral modified extracapsular thyroidectomy?
- If at surgery of the contralateral gland is normal size, it is likely to be producing T4
- Higher risk of hypocalcaemia than for unilateral. Some do staged procedures to reduce risk of hypocalcaemia
148
What is the anatomy of the parathyroid glands?
4 glands in total – 2 pairs
Intracapsular are caudal
Extracapsular are cranial
149
What are the clinical signs of primary hyperparathyroidism?
Hypercalcaemia
PUPD
Lethargy
Weakness
Subclinical
Markedly polydipsic but also may be incidental
150
How can you prevent post parathyroidectomy hypocalcaemia?
- Monitor blood calcium – at least twice a day for 2-3 days
- Vitamin D – 24h before surgery to increase calcium absorption from the GI tract and reduce losses through kidneys
151
What are the clinical signs of post parathyroidectomy hypocalcaemia?
- Loss of appetite
- Restless
- Stiff/weak
- Hypersensitivity to touch/sound
- Muscle tremors > progresses to twitching > spasms > seizures > death
152
How can calcium administration be done to manage post parathyroidism hypocalcaemia?
- Tricky to manage as the remaining parathyroid’s function will have been suppressed
- Exogenous calcium will slow recovery of parathyroid function
- Oral if level dropping but no clinical signs
- Intravenous if levels very low and/or clinical signs
153
What are the risks of iatrogenic hypoparathyroidism in thyroid and parathyroidectomies?
Unilateral thyroidectomy - low risk hypocalcaemia, low risk hypothyroidism
Bilateral thyroidectomy - higher risk hypocalcaemia, hypoparathyroidism more likely to be treated in dog than cat
Unilateral parathyroidectomy (primary hyperparathyroidism) - highest risk hypocalcaemia, low risk hypothyroidism
154
What is a sentinel lymph node?
Primary draining lymph node is used to identify local metastasis
155
How can sentinel lymph nodes be identified at surgery?
Not always the one we suspect, can be use Methylene Blue to identify it
