Para-nasal sinuses Flashcards
what are the 4 types
ethmoid, maxillary, sphenoid, frontal
what does the sinuses communicate with
the nasal cavity, PNS discharges fluid into the meatus, which lie at the middle conchae
frontal sinus
frontal bone
compartmentalised
ethmoid sinus
back of the NC, between orbits
small sinuses = ethmoid air cells [ant, middle, post]
least common
sphenoid sinus
roof of the NC
maxillary sinus
largest group
most common site
either side of the NC, underneath the zygoma
discharge fluid into the meatus, which lie at the middle conchae
what is a build up of fluid called
sinusitis
what lines the PNS
respiratory mucosa
goblet secreting cells, in which mucus drains into the NC
highly vascularised, ciliated columnar
olfactory mucosa lines the NC not the PNS
what is the blood supply
arterial: facial artery, a branch from the internal carotid artery
common carotid -> external + internal carotid which supplies the different regions
venous: lateral nasal vein -> facial vein -> IJ vein -> brachiocephalic -> IVC
what is the lymph supply
buccal nodes
parotid nodes
submandibular nodes
what is the nerve supply
sensory innervation
- opthalamic division
- maxillary division of the trigeminal nerve
what is the function
respiratory: warms and humidifies moistens inspired air
olfactory: nerve endings at the cribiform plate detects smell
speech: resonating chamber
what is the only sinus that uses TNM
maxillary
what shape is the maxillary sinus
pyramid shape: base of the pyramid forms lateral wall of the NC, apex extends to the zygomatic process
what does the superior aspect of MS comprise of
floor of the orbit and the ethmoid sinus
what does the inferior aspect of the MS comprise of
alveolar process and typically lies below the NC
describe the infra-orbital nerve
transverses the roof of the sinus whereas the second and first molar teeth, typically project the sinus floor. posterior wall extends into the infratemporal and pherygopalatine fossae
what does the MS drain
ostum maxillae beneath the middle conchae
describe the frontal sinus
full size at puberty
drains into the NC through the middle meatus beneath the middle conchae via the frontal nasal duct
how can tumours in the frontal sinus present
bone swelling
describe the location of the ES
upper part of the NC and between orbits
ant and middle drain into the NC via the middle meatus and posterior drains via the superior meatus beneath the superior conchae
where do the ES lie in respect to the optic nerves
optic nerves lie posterior to the sinus and the anterior cranial fossa lies superiorly
what pathology is ES commonly
adenocarcinoma
what separates the sinus from the orbit and NC
lamina papyracea
how is ES tumours presented
nasal obstruction and loss of smell
describe the location of the sphenoid sinus
deep in the base of the skull, beneath the pituitary gland
nasopharynx lies inferior and NC anterior
optic nerve and cavenous lies laterally
where does the sphenoid drain into
the NC via the sphenoethmoidal recess above the superior conchae of the NC
what is the presentation for a sphenoid tumour
deep seated pain, cranial nerve palsies
what is the lymphatic drainage
retropharyngeal and upper deep cervical
what does presentation related with
tumour location
what are the tumour presentation relations in terms of the MS
inf = pain in the teeth + ulceration
inf + post = trismus
sup =. proptosis and diplopia
medial = nasal stiffness with discharge
ant + lat = mass in cheeks
infraorbital nerve involvement can lead to numbness in the cheeks
diagnosis and staging
- inspection of the OC
- plain x-ray = bone erosion
- CT + MRI = locoregional staging
- CT = bony detail
- MRI = tumour distinction from adjacent structures
- orthopantogram = tooth preservation assessment
- histology assessment on cells
- nasal speculum = upper airway endoscopy
are LN mets rare
yes
do they have early or late presentation
late
what should be inspected
the air filled cavities with an endoscope
what is the ohngrens line
theoretical line which divides the MS, from the medial canthus to the angle of the mandible in the lateral plane
where can they spread to
to other adjacent sinuses via the mucosal layer
what are the sinuses line with
ciliated columnar epithelium
what are the pathological types
adenocarcinoma, adenoid cystic carcinoma, melanoma and lymphoma
what do the sinuses do
lighten the skull, gives resonance to voice
with good clearance with surgery what is the 5 year survival rate
50%
what is the survival rate
25-30%
what is the surgery types
endoscopic resection
craniofacial resection
matxillectomy (with or without exenteration)
partial or total maxillectomy, ethmoidectomy and/or sphenoidectomy
vascularised flap reconstruction
all dependent on size, extent, stage and type
what is the treatment for M + E
surgery + post op RT [except for rare T1 lesions]
describe RT
concurrent with chemo
post-op given to operative bed [tumour location and spread]
volume irradiation correlates with the investigation findings
tongue depressor moves inferiorly out of the volume,
volumes need to be delineated with contrast
retropharyngeal nodes need to be included
IMRT: improved coverage and sparing
do PNS have good local control
no, risk of treatment related sequelae
describe ethmoid RT
difficult to irradiate lies between the optic nerves
surgery + RT = increased local control
CTV = medial portion of maxilla, pterygoid fossa, ethmoid sinus + nasal fossa
3 field plan: ant + 2 lat
66-70Gy in 33-35 fractions
what is the margin and fields for the NC
CTV = lesion + 1cm margin
field = ant wedged pair
whole NC = ant + lat field
MS antrum RT
supine
mouthbite: lower OC + tongue out of the field
PTV close to the optic nerves, chiasm, orbit, temporal lobe and brainstem
CTV = M + ES, NC, pterygoid fossa + lat pharyngeal node
shielding of the brain stem, optic pathway, eyeball, lacrimal gland, and orbit
heavy weighted anterior and one/ two lateral field, non divergent field border, avoid exit dose to lens, 5-10 degree gantry angle
65-70Gy in 30-35 fractions
superior border of lat fields may be reduced to 50Gy to avoid exceeding optic nerve
columella RT
extensive = 2/3 field
superficial = direct ant electron field
wax block and wax nose plugs, produce homogenous tissue density for dose deposition
confined: 55Gy in 20
extending upper NC = 65-70Gy in 30-35
olfactory neuroblastoma
rare
surgery + adj RT
chemo for advanced
CTV is pre-operative GTV with a 1cm margin
margin includes bilateral NC, ES, cribiform plate, olfactory bulb
three field, IMRT
optic nerve and chiasm close by
60Gy in 30
