DEVIATED NASAL SEPTUM (DNS)

This is an important cause of nasal obstruction.
Aetiology
Trauma and errors of development form the two import
facto rs in the causation of deviated sepcum.
1. Trauma. A lateral blow on the nose may cause displacement
of septal cartilage from the vomerine groove
and maxillary crest, while a crushing blow from the front
may cause buckling, twisting, fractures and duplication of
nasal septum with telescoping of its fragments. Injuries to
the nose commonly occur in childhood but are often
overlooked. Even the history may not be forthcoming.
- Trauma may also be inflicted at birth during d
hour when nose is pressed during its passage through
the birth canal. Birth injuries should be immediately
attended to as they result in septal deviation later in life.
2. Developmental error. Nasal septum is formed by
the tectoseptal process which descends to meet the two
halves of the developing pa late in the midline. During
the primary and secondary dentition, further development
takes place in the palate, which descends and
widens to accommodate the teeth.
Unequal growth between the palate and the base of
skull may cause buckling of the nasal septum. In mouth
breathers, as in adenoid hypertrophy, the palate is often
highly arched and the septum is deviated
Similarly, DNS may be seen in cases of cleft lip and
palate and in those with dental abnormalities.
3. Racial factors. Caucasians are affected more than
Negroes.
4. Hereditary factors. Several members of the same
family may have deviated nasal septum.
Types of DNS
Deviation may involve only the cartilage, bone or both
the cartilage and bone .
1. Anterior dislocation. Septal cClrtiiage may be dislocated
into one of the nasal chambers. This is better
appreciated by looking at the base of nose when patient's
head is tilted backwards
2. C-shaped deform ity. Septum is deviated in a simple
curve to one side. Nasal chamber on the concave side
of the nasal septum will be wider and may show com pensmory
hypertrophy of turbinates.
3. S-shaped deformity. Septum may show as-shaped
curve either in vertical or anteroposterior plane. Such a
deformity may cause bilateral nasal obstruction.
4. Spurs. A spur is a shelf- like projection often found
at the junction of bone and carti lage. A spur may press on
the latera l wall and gives rise to headache. It may also predispose
to repeated epistaxis from the vessels stretched on
its convex sUlface.
5. Thickening. It may be due to organised haematoma
or over-riding of dislocated septal fragments.
Clinical features
DNS can involve any age and sex. Ma les are affected
more than females.
1. Nasal obstruction. Depending on the type of septal
deformity, obstruction may be unilateral or bilateral.
Respiratory c urrents pass through upper part of nasa l cavity,
therefore, high. septal deviation cause nasa l obstruction
more than lower ones.
When examining a case of nasal obstruction, one should
ascertain the site of obstruction in the nose. It could be (1)
vestibular (caudal septal dislocation, synechiae or stenosis),
(2) at the nasal valve (synechiae, Llsually post-rhino.plasty),
(3) attic (a long the upper part o.f nasal septum due to high
septal deviat ion; (4) turbinal (hypertrophic turbinates or
concha bullosa); and (5) choanal (choanal atresia or a
choanal polyp.) unilateral choana1 atresia maY be missed
in infancy and childhood. Choanal polyp may be missed
on the anterior rhinoscopy unless posterior rhinoscopy or
nasal endoscopy is done.
Cottle test. It is used in nasal obstruction due to abnormality
of the nasa l valve. In this test, cheek is drawn laterally
while the patient breathes quietl y. If the nasal
airway improves on the test side, the test is positive, am.!
indicates abnormality of the vestibular component ot'
nasal valve
2. Headache. Deviated septum, especially a spur.
may press on the latera l wall of nose giving rise to
pressure headache.
3. Sinusitis. Deviated septum may obstruct sinu,
ost ia resu lting in poor ventilation of the sinuses.
Therefore, it forms an important cause to predispose or
perpetuate sinus infec tions.
4. Epistaxis. Mucosa over the deviated part of septum
is exposed to the dryi ng effects o.f air cu rrents leading
to. formation of crusts which when removed, cause
bleed ing. Bleeding may a lso occur from vessels over a
septal spur.
5. Anosmia. Fa ilure of the inspired air to reach tht'
olfactory region may res ult in total or partial loss of sens
of smell
6. External deformity. Septal deformities may be
associated with deviation of the cartilaginous or both
the bony and cartilaginous dorsum of nose, deform itie
of the nasal tip or columella.
7. Middle ear infection. DNS also predisposes to middle ear infection.
Treatment
Minor degrees of septal deviation with no sympwms are
commonly seen in patients and require no treatment. It
is only when deviated septum produces mechanical nasal
obstruction or the symptoms given above, that an operation
is indicated.
Submucous resection (SMR) operation. It is generally
done in adu lts under local anaesthesia. It consists
of elevating the mucoperichondrial and mucoperi os teal
flaps on either side of the septal framework by a single
incision made on one side of the septum, removing the
deflected parts of the bony and cartilaginous septum, and
then repositioning the fl aps (see section on Operative
Surgery for details).
Septoplasty. It is a conservative approach to septa l
surgery. In this operation, much of the septal framework
is retained. Only the most deviated parts are removed.
Rest of the septal framework is corrected and repositioned
by plastic means. Mucoperichondrial/periosteal
flap is generally raised only on one side of the septum,
retaining the attachment and blood supply on the other.
Septoplasty has now almost replaced SMR operation.
Septal surgery is usually done after the age of 17 so as
not to interfere with the growth of nasal skeleton.
However, if a child has severe septal deviation causing
marked nasal obstruction, conservative septal surgery
(septoplasty) can be performed to provide a good airway.