an overview of the paranasal sinuses.ppt

Definition and Terminology
PD is characterized by idiopathic progressive expansion of one or more paranasal sinuses beyond the normal margins, without evidence of mucous membrane changes. The expansion may involve the complete sinus or a part of it.3

The medical literature offers various labels to describe enlargement of the sinus by air, including frontal sinus hypertrophy, PD, pneumosinus frontalis, aerocele, pneumocele, sinus ectasia, hyperpneumatization, pneumatocele, air cyst, and others.1,4,5

The varying terminology used to describe abnormal expansion of the frontal sinus has caused some confusion about the etiology and diagnosis of the condition.1 Urken et al4 classified the deformity into three groups—hypersinus, pneumocele, and PD—as follows:

Hypersinus or hyperpneumatization was defined as an enlarged frontal sinus that has developed beyond the upper limits of normal. The walls are normal, and the hyperaerated sinus does not extend over the normal limits of the frontal bone. The patient is asymptomatic, and the condition requires no intervention.1

Pneumocele refers to an aerated sinus with variable thinning of the sinus walls. The thinning, focal or generalized, differentiates pneumocele from PD. It is a pathological abnormality.1

PD is a condition where the sinus abnormally expands beyond the normal limits of the frontal bone. The bony walls of the sinus are of normal thickness, but are displaced, causing frontal bossing. There is no evidence of erosion, and the mucosa is of normal appearance. The frontal sinus is most commonly affected, and the ethmoidal, sphenoidal, or unilateral maxillary sinus may be involved.6,7

Etiology
The etiology of primary PD has been the source of great debate for many years. It is still unknown, but eight possible mechanisms have been proposed as follows: a spontaneously draining mucocele, the presence of a gas-forming microorganism, the presence of a one-way valve, congenital abnormality, hormonal change, local growth disturbances, osteoclastic and osteoblastic activity, and trauma.1,7-9

Generally, frontonasal duct obstruction of any cause and the subsequent increase in sinus pressure seem to be the most important factors in the pathogenesis of PD.1,3,4 In this case, the ostium was inspected and found to be macroscopically normal, and we did not find a clear etiology.

Review of the literature reveals that age at presentation varies from puberty to the elderly, but PD has not been reported in children. This may be due to the age at which the normal paranasal sinus develops, as well as the gradual onset of PD.5,6

Diagnosis
Diagnosis is made by clinical examination, and confirmation by radiography (plain film or CT), when the characteristic enlargement of the sinus is seen.7,8

Clinical symptoms are typically related to the displaced structures. In the case of outward expansion, the typical signs are frontal bossing and prominence of the supraorbital ridge.

1. PARANASAL SINUSES -
ANATOMY & PATHOLOGY
PRESENTER:
DR ASHOK SHARMA
JUNIOR RESIDENT II
GUIDE:
DR P.K. LAMGHARE SIR
& DR MOHIT PATIL SIR

2. PARANASAL SINUSES
The large, air-filled cavities of the paranasalsinuses are
sometimes called the accessory nasal sinuses because they
are lined with mucous membrane, which is continuous with
the nasal cavity. These sinuses are divided into four groups,
according to the bones that contain them:
1.Maxillary (2) Maxillary (facial) bones
2. Frontal (usually 2) Frontal (cranial) bones
3. Ethmoid(many) Ethmoid(cranial) bones
4. Sphenoid (cranial) bone

3. They lighten the Facial skeleton
Air-conditioning of the inspired
air by providing large surface
area over which the air is
humidified and warmed.
To provide resonance to voice.
They are lined by
Psuedostratified columnar
epithelium studded with
mucus and serous glands.
Function Histology

4. [email protected]

5. Maxillary Sinuses
The large maxillary sinuses are paired structures, one of which is
located within the body of each maxillary bone.
Each maxillary sinus is shaped somewhat like a pyramid on a frontal
view. Laterally, they appear more cubic. The average total vertical
dimension is between 3 and 4 cm, and the other dimensions are
between 2.5 and 3 cm.
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6. Osteomeatal unit
•The osteomeatal unit (OMU) includes the (1) maxillary
sinus ostium, (2) ethmoid infundibulum, (3) anterior
ethmoid air cells, and (4) frontal recess.
•The OMU is the key factor in the pathogenesis of chronic
sinusitis.

8. Frontal Sinuses
The frontal sinuses are located between the inner and outer tables of the
skull, posterior to the glabella; they rarely become aerated before age 6.
The frontal sinuses are always paired and are usually fairly symmetric in
size and shape; the frontal sinuses are rarely symmetric.

9. Ethmoid Sinuses
The ethmoid sinuses are contained within the lateral masses or
labyrinths of the ethmoid bone. These air cells are grouped into anterior,
middle, and posterior collections, but they all intercommunicate.
When viewed from the side, the anterior ethmoid sinuses appear to fill
the orbits. This occurs because portions of the ethmoid sinuses are
contained in the lateral masses of the ethmoid bone, which helps to form
the medial wall of each orbit.
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10. Sphenoid Sinuses
The sphenoid sinuses lie in the body of the sphenoid bone directly below
the sella turcica. The body of the sphenoid that contains these sinuses is
cubic and frequently is divided by a thin septum to form two cavities. This
septum may be incomplete or absent entirely, however, resulting in only
one cavity.

11. The Lateral Wall of Nasal Cavity
Marked by 3
projections:
•Superior concha
•Middle concha
•Inferior concha
•The space below
each concha is
called a meatus.

12. The Lateral Wall of Nasal Cavity
1.Inferior meatus:
nasolacrimal duct
2.Middle meatus:
•Maxillary sinus
•Frontal sinus
•Anterior ethmoid
sinuses
3.Superior meatus:
posterior ethmoid
sinuses
4.Sphenoethmoidal
recess: sphenoid
sinus

13. LATERAL VIEW
Lateral side of the skull lies against
the film and x-ray beam is projected
perpendicular from the other side.
Center CR to a point midway between
outer canthus and EAM.

14. LATERAL POSITION—RIGHT OR LEFT LATERAL: SINUSES
Respiration
Suspend respiration during exposure.

15. Structures Shown: • All four paranasal sinus groups are
shown.

16. STRUCTURES SEEN -
ANTERIOR AND POSTERIOR EXTENT
OF SPHENOID, FRONTAL AND
MAXILLARY SINUSES
SELLA TURCICA
ETHMOID SINUSES
CONDYLE AND NECK OF MANDIBLE

17. CALDWELL VIEW
•A/K/A OCCIPITOFRONTAL VIEW OR
NOSE FOREHEAD POSITION

18. Part Position
Place patient's nose and forehead against upright table
with neck extended to elevate the OML 15°from horizontal. A
radiolucent support between forehead and upright Bucky or
table may be used to maintain this position. CR remains
horizontal. (alternate method if Bucky can be tilted 15°.)
Center X-RAY to CR and to nasion, ensuring no rotation.
Align CR horizontal, parallel to floor.

19. POSITION: SINUSES Caldwell Method
.

20. Structures Shown: • Frontal sinuses projected above the
frontonasal suture. • Anterior ethmoid air cells visualized lateral to
each nasal bone, directly below the frontal sinuses.

21. STRUCTURES SEEN
1.FRONTAL SINUSES (SEEN BEST)
2.ETHMOID SINUSES
3.MAXILLARY SINUSES
4.FRONTAL PROCESS OF ZYGOMA AND
ZYGOMATIC PROCESS OF FRONTAL
BONE
5.SUPERIOR MARGIN OF ORBIT AND
LAMINA PAPYRACEA
6.SUPERIOR ORBITAL FISSURE

22. WATER’S VIEW
OCCIPITOMENTAL VIEW OR NOSE
CHIN POSITION
IT IS TAKEN IN SUCH A WAY THAT
NOSE AND CHIN OF THE PATIENT
TOUCH THE FILM WHILE X-RAY BEAM
IS PROJECTED FROM BEHIND.

23. Part Position
• Extend neck, placing chin and nose against table/film.
• Adjust head until MML is perpendicular to film; OML will form
a 37°angle with the plane of the film.
• Ensure that no rotation or tilt exists.
• Center film to CR and to acanthion.

24. PARIETOACANTHIAL PROJECTION: SINUSES Waters
Method

25. Structures Shown: • Maxillary sinuses with the inferior
aspect visualized free from superimposing alveolar
processes and petrous ridges, the inferior orbital rim, and
an oblique view of the frontal sinuses

26. STRUCTURES SEEN
•Maxillary sinuses (seen best)
•Frontal sinuses
•Sphenoid sinuses (if the film is taken with
open mouth)
•Zygoma
•Zygomatic arch
•Nasal bone
•Frontal process of maxilla

27. SUBMENTOVERTICAL (BASAL)
VIEW
THE VIEW IS TAKEN WITH VERTEX NEAR THE
FILM AND X-RAY BEAM PROJECTED AT RIGHT
ANGLES TO THE FILM FROM THE SUBMENTAL
AREA.

28. Part Position
• Raise chin, hyperextend neck if possible until
OML is parallel to table/film.
• Head rests on vertex of skull.
• Ensure no rotation or tilt.

29. SUBMENTOVERTEX (SMV) PROJECTION: SINUSES

30. STRUCTURES SEEN
•Sphenoid, posterior Ethmoid and Maxillarry sinuses
(seen best in that order)
•Mandible

31. Structures Shown: • Sphenoid sinuses,
ethmoid sinuses, nasal fossae, and maxillary
sinuses.

32. PARIETOACANTHIAL TRANSORAL PROJECTION: SINUSES
Open Mouth Waters Method

33. Structures Shown: • Maxillary sinuses with the inferior aspect visualized, free from
superimposing alveolar processes and petrous ridges, the inferior orbital rim, an
oblique view of the frontal sinuses, and the sphenoid sinuses visualized through
the open mouth.

34. Advantages of x-ray imaging in rhinology
include:
1. Cost effectiveness of the investigation
2. Easy availability
3. Currently available digital x-ray imaging
techniques provide better soft tissue and
bone resolution when compared to
conventional x-rays.

35. Disadvantages of conventional radiographs:
1. Plain radiographs have a false positive
rate of 4%.
2. Plain radiographs have false negative rate
of more than 30%

36. CT NOSE
AND PNS

37. BASIC CONCEPTS
•CT scans typically obtained for visualizing the
paranasal sinus should include coronal and axial (3-
mm) cross
sections.
Soft tissue and bony windows facilitate evaluation of
disease processes and the bony architecture.
The use of intravenous contrast material just prior
to scanning can help define soft tissue lesions and
delineate vascularized structures, such as vascular
tumors.
Contrast-enhanced CT is particularly useful in
evaluating neoplastic, chronic, and inflammatory
processes.

38. The CT scan is the GOLD STANDARD
investigation in all preoperative cases as it
gives detailed bony anatomy of the area
and serves as a ‘road map’ for the
operating surgeon.
CT scans are best done after a course of
antibiotics, so that acute inflammation is not
mistaken for chronic mucosal disease.

39. CROSS SECTIONAL ANATOMY –
AXIALS

48. CORONAL ANATOMY

56. SAGITTAL ANATOMY

60. PATHOLOGY OF THE
PARANASAL SINUSES

61. SINUSITIS
Sinusitis is the inflammatory
condition of the mucous
membrane lining of the
sinuses. It may progress to
pus formation.
Sinusitis may be acute and
chronic.
•inflammation of the maxillary
sinus is called maxillitis;
•inflammation of the
ethmoidal sinus is called
ethmoiditis;

62. SINUSITIS
•inflammation of the
frontal sinus is called
frontal sinusitis;
•inflammation of the
sphenoid sinus is
called sphenoiditis;

63. SINUSITIS
•hemisinusitis –the
involvement all
sinuses on one side
into inflammation
process;
•pansinusitis –all
sinuses are involved;
•polisinusitis –
several sinuses, but
not all, are involved

64. SINUSITIS
Sinusitis may divided into:
•Rhinogenous –infection spreads from
the nasal cavity. It is the most common
way for infection and such sinusitis is
the complication of the flu.
•Odontogenic –infection spreads from
upper teeth. This way is typical only for
maxillary sinus. The pathologic process
may spreads from 4,5,6 cheek-teeth
apex to the inferior wall of the maxillary
sinus
•Traumatic
•Hematogenic
•Allergic.

65. SINUSITIS
ACUTE sinusitis are
divided into:
•Catarrhal.
•Purulent.
•Necrotic.
CHRONIC:
•Purulent
•Polyps of sinuses
•mixed

66. SINUSITIS SYMPTOMS
Common symptoms:
•rise in temperature
•bad appetite
•sleep disturbances
•changes of the blood
(leukocytosis)
Local symptoms:
•Pain located in the affected
sinus.
•Nasal obstruction.
•Purulent discharge from the
nose.
•Oedema of facial tissues.
•Watering.
•Smell disturbances
(hyposmia).

67. ONE-SIDED MAXILLARY
SINUSITIS

68. ONE-SIDED
ETHMOIDITIS

69. ONE-SIDED
SPHENOIDITIS

71. FUNGAL SUNUSITIS

76. OSTEOMA

77. Mucocele

78. Fibrous dysplasia

79. INVERTED PAPILLOMA

80. JUVENILE NASOPHARYNGEAL ANGIOFIBROMA

81. ESTHESIONEUROBLASTOMA
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82. ADENOCYSTIC CA

83. AMELOBLASTOMA

84. THANK YOU