Ch 124 Basic eye surgery Flashcards
Anatomy eyelids
- All eyelid muscles are innervated by the branches of the facial nerve, except for the levator palpebrae superioris (oculomotor nerve)
- Sensation to the eyelids and corneal surface is provided by branches of the trigeminal nerve,
suture
- polyglactin can be and is routinely used for skin apposition around the eyelids.
- excellent knot security and handling, along with the fact that it becomes soft when wet, make it a good choice
- absorbable, polyglactin sutures do not need to be removed
Eyelid Neoplasia
- meibomian gland tumors, squamous papillomas, melanomas, and histiocytomas make up more than 80% of all eyelid tumors
- removal we recon
- enucleation of the globe may be necessary
Eyelid reconstruction techniques
- Two-layer closure used to appose margin: Mattress suture to appose tarsus and orbicularis muscle layer + Figure of eight suture for skin
- Sliding Pedicle Advancement Flap (Defects that involve more than one-third of the eyelid margin)
- Myocutaneous Pedicle Graft (reconstruction of defects of the upper eyelid that involve large portions of the eyelid margin)
- Semicircular Flap
- Lip-to-Lid Flap
Nictitating Membrane Gland
prolapse (Cherry eye)
- Orbital Rim Anchoring Technique
- Morgan Pocket Technique
Excision of the Nictitating Membrane
- Hemangiomas are the most common in dogs and squamous cell carcinomas in cats.
orbit anatomy
- medial, dorsomedial, and lateral walls of the orbit are bone
- muscles of mastication and soft tissues of the soft palate make up the dorsolateral and ventral orbital boundaries
- sphenoid bone, which forms the caudomedial boundary of the orbit.
- Distinct compartments within the orbit are formed by reflections of the fibrous periorbita (also called the orbital septum)
Space-occupying lesions reported to cause exophthalmos
- tumors,
- zygomatic mucoceles
- arteriovenous malformations
- extraocular and masticatory muscle myositis
- hemorrhage
- orbital cellulitis or abscessation
Definitive diagnosis, determination of the full extent of involvement, and surgical planning usually require CT or MRI and fine needle aspiration or biopsy.
retrobulbar abscess
- transoral orbitotomy to provide drainage and obtain bacterial culture and sensitivity
- surgical treatment is rarely indicated because most orbital abscesses respond to medical therapy
Exenteration
- removal of all the orbital contents
- Care must be taken not to remove the muscular floor of the orbit or lacerate the maxillary artery that runs through it.
Orbitotomy
Modified Lateral Orbitotomy
- used for all extraconal lesions, except for those medial to the muscle cone, and all intraconal lesions.
- orbital ligament is transected
- facial vein and venous plexus that are closely associated with the rostral extent of the zygomatic arch
- osteotomy
Orbitectomy
- When neoplasia affects the bones of the orbit, chemotherapy or radiation therapy alone may not provide satisfactory control
Globe removal - enucleation
Subconjunctival Approach:
- incision through the conjunctiva and Tenon’s capsule
- Care must be taken to avoid lacerating the angularis oculi vein, which runs over the surface of the medial orbital rim
- Care must be taken to not place too much traction on the globe when transecting the optic nerve
- remove all of the conjunctival tissue
- third eyelid is excised
Transpalpebral Approach
- An incision through the skin, completely surrounding the palpebral fissure
- xtraocular muscles are visualized, they should be transected at their tendinous attachment to the globe
-
Strontium 90 plesiotherapy for the
treatment of eyelid squamous cell
carcinoma in eight cats
Onne-Marju Russak 2022
In six
cases, ST-90 was used as the only treatment modality, while in two cats it was used as an adjuvant to surgery. Four
cats received a single protocol and four a hypofractionated protocol. In the six cats in which ST-90 was used as the
primary treatment, the response was 100%.
no signs of recurrence at a median time of
34 months
early stage (such as carcinoma in situ Tis or T1),
SE: alopecia
Tumours involving the retrobulbar
space in cats: 37 cases
Bryn A Jones 2022
Thirty-two cases (86%) had secondary extension
of neoplasia to the retrobulbar space (most commonly from the nasal cavities), (54%), of which
12 were lymphoma.
36 (97%) retrobulbar tumours were malignant. Thoracic imaging,
where it was performed, was concerning for metastasis in 8/25 cases (31%), with abdominal imaging suggestive of
metastasis in 5/12 (42%).
The most common diagnosis was lymphoma with 19 cases (51%), carcinoma in 10 (27%). The median survival time, for cases where death was
recorded, was 85 days (range 1–263 days).
Patterns of bacterial culture and antimicrobial
susceptibility test results for dogs
with retrobulbar abscesses: 133 cases (2002–2019)
Stephanie A. Pumphrey 2020
multiple isolates recovered from 54 (56%) of those dogs.
34 (49%) had purely aerobic infections,
15 (22%) had mixed aerobic and anaerobic infections,
20 (29%) had purely anaerobic infections. Pasteurella, streptococcus spp (20), and Escherichia coli (12) were the most common aerobic Bacteroides , Actinomyces, and Fusobacterium (10) most common anaerobic
Susceptibility test results led to changes in (46%) dogs. 78 (97%) recovered
amoxicillin-clavulanate or a combination of clindamycin and enrofloxacin as first-line treatments
X/Y shaped periorbital reconstructive
surgery following enucleation or
exenteration in dogs and cats: 24 cases
(2013-2020)
Vlachomitrou 2021
cinti
Nineteen dogs and five cats were included in the study
two cats and two dogs showed eyelid depression (16%)
incisions parallel to the orbital rim of the frontal bone were made into the collagenous
connective tissue and periosteum
Transorbital postcaruncular endoscopic surgery
as an alternative to orbital exploratory surgery: A cadaveric
study and case report in a dog with an orbital sarcoma
Filipe N. C. M. Espinheira Gomes
Transorbital endoscopy was performed to obtain biopsies of an
orbital apex mass by using a postcaruncular approach. A 2.7-mm 30 rigid
endoscope fitted with a cystoscope working sheath was used with the aid of a
blunt suction-dissector and fluid ingress
This technique should be considered in cases in which a
histological diagnosis is required prior to definitive treatment as a method to
obtain biopsy samples of the orbital apex region without major surgical dissection.
Use of a temporalis fascia transposition flap for ventral orbital
stabilization after ventral orbitectomy in a dog
Brian Dent 2019
No complications occurred during the procedure
Clinical significance: A temporalis fascia transposition flap can be used to reconstruct
the ventral aspect of the orbit in dogs.
alternative
- masseter muscle flap
- cerclage wire,
- polypropylene mesh,
- orthopedic steel plate
Outcome of secondary intention healing of full thickness lower eyelid defects in dogs
M. W. Jack 2019
krosse
three dogs
70 to 90% of the lower eyelid margin
not all lower eyelid resections require anatomical reconstruction. Selected cases can be left to heal by secondary intention with minimal post-operative complications
anatomical reconstruction is traditionally recommended because corneal health is thought to rely on normal eyelid position and integrity
> dogs were able to move their third eyelid laterally when blinking. This can occur due to abducens nerve stimulation
