Nasal Septum

OUTLINE

 

  • Embryology

  • Anatomy
  • Pathologic Anatomy Of Cartilage

  • Indications For Nasal Septal Surgery

  • Techniques Of Septal Surgery

  • Sequence Of Techniques In Septorhinoplasty

  • Complications Of Septal Surgery

 

Septoplasty History: first made in 1757 with Quelmaltz's daily digital pressure for gradual correction.

Adams (1875) advocated fracture and splinting of the nasal septum.

Ingals 1882 removing a small triangular piece of cartilage

Hinderer, 1971). Krieg (1889) Boeninghaus (1900): removing deformity & nasal mucosa.

Asch (1899) altering the spring of the cartilage with full-thickness cruciate incisions.

Freer (1902) and Killian (1904) concepts of submucous resection (SMR)

Metzenbaum (1929), Metzenbaum's "swinging door" technique

Cottle (Cottle and Loring, 1947) septoplasty methods.

EMBRYOLOGY

-development of nose begins week 3 of fetal development

-starts with thickening of cranial ectoderm (precursor of paired olfactory placodes)

-5th week, Þ lateral and medial nasal swellings appear as ridges surrounding the placodes,

which become depressed to form epithelium-lined nasal pits (Moore, 1973).

-deepening of these pits separates the frontonasal process into medial and lateral

-medial component fuses to form primitive nasal septum.

-inferiorly, the paired maxillary processes of first branchial arches grow anteriorly and medially to fuse with the medial nasal processes.

-6th week;Þ nasal pits extend posteriorly & form bucconasal memb (separates nasal & oral) Subsequent membrane rupture forms choanae.

Þ nasal septum, grows simultaneously toward sphenoidal process in post direction.

-3rd fetal mnth; mesenchymal condensation begins & cartilage grows in from sphenoid to

form two adjacent plates which fuse with one another & also ventrally with

lateral nasal walls to form the nasal capsule.

-5th month, & well into adolescence, ossification of posterior part of cartilaginous capsule nb: -perpend plate of ethmoid remains fibrous until 3rd year, then ossifies

-vomer, develops from CT astride septal cartilage not by ossification of cartilage

-6th fetal month, ingrowth of connective tissue divides capsule into lower & upper lateral cartilages as well as septal cartilage.

Nasal septum:

-made up of:

-bony: parts of maxillary, palatine, vomerine & ethmoid bones,

nasal spine of frontal bone & premaxilla

-cartilage: Quad cartil, upper lateral cartilages, membranous septum, & columella

Maxillary crest: F’d by perpendicular projections from maxilla and palatine bone.

-In its groove lies quadrilateral cartilage anteriorly and vomer posteriorly.

-Cartilage articulates via fibrous attachments (occasionally, fat is interposed)

-articulation b/w vomer and maxillary crest is fibrous early in life, & becomes bony after both structures have ossified

Septal cartilage:

-four borders: dorsal, ventral, caudal, and cephalic (see Fig. 46-1).

-most caudal portion:

-extends beyond (anterior to) nasal spine (to which is attached +++).

-is insinuated into posterior aspect of columella, b/w two medial crura.

-cephalic border:

-where it lies against perpendicular plate is the thickest (5-7 mm) part of septal cartilg. -cephalic extent varies considerably, & can reach beyond midpoint of the nasal bones.

-septal cartilage articulates with upper lat cartilages at the rhinion (Fig. 46-4).

-dorsal edge of septal cartilg has a groove that cephalically accepts nasal spine of frontal bone, and just caudally, the keel-like undersurface of the nasal bones (Fig. 46-4).

nb: these form the keystone area of nasal support, (structure of substantial strength)

-nb: -no relationship between thickness of septal cartilage and perpendicular plate.

-upper lateral cartilages & septum are separate cartilages, housed in own compartments (serves to tamponade and localize bleeding)

-septal fractures are usually confined to the free nasal tip and are vertically oriented.

-fractures may occur in an oblique fashion and can extend from nasal spine to rhinion

A, Through upper lateral cartilages; B, at rhinion (keystone area); C, root of nose (also radix).

Perpendicular plate of the ethmoid bone (perpendicular lamina).

-polygonal

-descends downward from cribriform plate

-makes up large part of nasal septum.

-contribution to nasal support is minimal.

-chief significance is related to its presumed role in shock absorption.

-anterior border is grooved to receive nasal process of frontal bone & the joined nasal bones.

-caudal edge: thickened where it lies against septal cartilage.

-lower edge curves sharply as it lies in groove on superior surface of vomer.

Mucoperiosteal and mucoperichondrial linings:

-contains its blood and nerve supply (ie b/w perichondrium & overlying mucosa)

nb: vessels run in an anteroposterior direction along the septum

PATHOLOGIC ANATOMY OF CARTILAGE

Causes of bent cartilage:

i. congenital disproportion, (ie cartilaginous component is too large for housing in which it grows

nb: as it bends, it generates intrinsic tension.

ii. long-term results of trauma sustained earlier in life (more common cause).

-usually resists many episodes of trauma because of its elasticity.

BUT even minor trauma to the developing nose Þ significant effects on development

-3 distinct periods in early development of nose (Hinderer 1971):

-first period lasts for 5 years and is distinguished by rapid growth,

-next 5 years are noted for relative quiescence,

-last 5-year period is associated with another acceleration of growth.

-neonatal period trauma:

-most nasal deformities in newborns occur during labor or birth

-nb: cartilaginous nasal tip is most prominent facial structure by 2-3cm

-early life trauma to septum results Þ gradual bowing and deviation of cartilage,

Þ asymmetric growth of nose, septal membranes, and underlying skeletal parts.

-majority of microfractures occurring early in life are vertically oriented.

-Steiner (1959): nasal trauma may occur at any time after fourth month of gestation.

-Cottle (1951):distinction b/w temporary nasal flattening from delivery VS permanent damage in-utero b/c nasal septal deformities are sometimes noted in neonates born by cesarean

Intrinsic factors

-In vitro studies Þ cartilage has definable intrinsic stress system & if disturbed by fractures,

Þ an imbalance that can lead to warping or bending.

-Histological explanation:

-chondrocytes are concentrated at periphery of cartilage, whereas central portion is acellular.

-if one side of cartilage is interrupted with partial-thickness cuts (or a microfractures from early life) Þ opposite side assumes dominance, Þ warping of cartilage in that direction (Fig. 46-5).

Then as fibrous ingrowth fills the microfracture, permanence is established.

-nb: magnitude of these stresses vary in different areas of septum, as well as b/w different septums.

\ partial cuts are good in some areas of cartilage but not others. (?? need for full-thickness cuts)

A, Partial cuts leading to, B, convex bending.

C, Counteracting partial-thickness cuts on opposite side, Þ equalizing peripheral dominance

D, Note chondrocyte concentration on periphery of cartilage & relative acellularity in center.

Extrinsic factors

-premaxillary spine (abN’lly large/lateralized) can Þ displacement of base of caudal septal cartilage

-maxillary crest-vomer relationship abnormalaty also can Þ displacement of nasal septum.

nb: spurs can be due to:

-distorted appearance of normal bony anatomy.

-vomer is actually fractured, leaving its lower edge lying in the groove of the maxillary crest.

-perpendic plate of ethmoid deformity can Þ marked deviation of junction area with septal cartilg.

-previously depressed nasal bone

-upper lateral cartilage assymetry

-any lateral nasal structure (e.g., a turbinate) can disproportionally impinge on nasal septum

NORMAL NASAL PHYSIOLOGY

-nasal "valve" (Mink 1903)

-space b/w most caudal margin of upper lat cartilage & nasal septum.

-this angle is apprx 10-15 degrees, (if > 15 Þ prob with N functn).

-controls "shape" (change from columnÞ sheet), resistance & velocity of inspired air currents

-resistance of nasal valve results in a greater depth of respiration (Hinderer, 1971).

-area can be disturbed by deviation of nasal septum or by bowing effect of a flattened nose -velocity of airflow must be within a critical zone; if too fast/slow, valve collapses against septum.

-certain resistance is necessary for the air conditioner, and filter to work well.

(air in nasopharynx is maintained at temp of 30°-37° C with 75% or greater relative humidity)

-in quiet respiration nose accounts for 50% of total airway resistance (nasal valves make up most)

INDICATIONS FOR NASAL SEPTAL SURGERY

-elective surgical procedures,\ no absolute indications, only relative.

influenced by age, economic status, and social and environmental needs.

-2 categories of indications: procedures for primary abnormalities & those associated with rhinoplasty.

I. Septal surgery for primary septal pathology

Nasal obsrtuction:

-Nasal obstruct’n is subjective (??snoring, mouth breathing, dryness of pharynx, watch pt breathe)

-Rhinomanometry used to quantify nasal airflow,(?? role in preop evaluation)

-other med probs (eg chronic lung disease)

-Athletes (?? musicians ..ZB) better performance with functional nasal breathing vs oral only.

-Nasal obstrctn has been assoctd with hypoxia, ß ‘d pulmonary function, sudden death, sleep apnea

-Exercise-induced asthma is related to pulmonary ambient temp & humidity; \ improvement in nasal breathing secondary to septoplasty has been shown to improve this condition

-alterations in airflow currents result. Þ drying, crusting, and metaplastic changes of mucosa on the side with increased flow.

Bleeding

-abnormal air turbulence secondary to intranasal deformity Þ excessive mucosa drying & crusting Þ recurrent bleeding.

-septoplasty for access to bleeding site.

Sinus drainage

-if deviated nasal septum impinges onOMC

II Septal surgery as part of functional or cosmetic rhinoplasty

TECHNIQUES OF SEPTAL SURGERY

Contemporary methods: emphasis on straightening septal cartilage rather than removing it.

Correcting extrinsic defects

-elevate membranes one or both sides & inspect overall pathology,

-separate septal cartilage from most of its bony attachments, and,

-expose postr part of nose(ie perpendic ethmoid plate& vomer) by displacing cartilage to one side

-posterior deformities are managed by removing bone.

-septal cartilage is then altered in a manner dictated by the problem at hand.

-to ensure a narrow septal base and allow the cartilage to seek midline freely, a large portion of

vomer and maxillary crest is often removed.

-anterior maxillary spine is almost always preserved as its periosteum provides a sturdy tissue to which the septal cartilage, which is now free, is reattached.

Steps of dissection

- incision: a hemitransfixion incision, at caudal rim of septal cartilage.

-dissection into subperichondrial plane

-sharp dissection against bone of crest to enter subperiosteal plane elevate off floor.

-separation of septal cartilage from bone of perpendicular plate and is carried down to vomer and forward along it to anterior maxillary spine. -boomerang-shaped piece of cartilage is excised along edge of cartilage.

-septal cartilg should then swing freely with opp mucoperichond flap intact.."swinging door"

-door is displaced laterally with speculum, & bony septum can be inspected +/- removed

-chisel is used to cut maxillary crest along floor, starting just posterior to ant maxillary spine

-a bone scissors is used to cut the perpendicular plate superiorly avoiding #of cribriform plate

-remaining portions of deviated ethmoid plate and vomer can then be removed.

-Attention is then directed to the cartilage that is the "swinging door.":

If it is straightÞ suture base of caudal septum to periosteum of antr maxillary spine.

- If deviated,

-if old # line filled with fibrous tissue is seen, # line & adjacent cartilage is excised.

-if deviation is more complex:

-partial-thickness cutting of cartilage on concave side to make it straighter.

-full-thickness incisn on concave curvature or wedge excisin on convex surface

-morselization, or "checkerboard" gridding

-sometimes necessary to elevate both mucoperichondrial membranes.

nb; elevation of both membranes totally deprives cartilage of blood supply

-cartilage grafts have been used.

-crushed cartilage replaced.

-membrane-approximation with 4-0 plain catgut (ie thru & thru quilting suture).

-incision is closed.

-packed to prevent hematoma and for support.

COMPLICATIONS OF SEPTAL SURGERY

Hematoma & Hemorrhage

-potentially serious complication.

-cartilage deprived of its blood supply can be absorbed.

ß metabolic activity of cartilage begins promptly after separation from its blood supply.

-unless infected cartilage stays alive for about 3 days, \ needs Rx in < 3 days!!!

-after 3 days at body temperature, chondrocyte death results Þ absorption

-Chondrocytes make chondromucoprotein, collagen, elastin, and the matrix around it.

-?? pressure from expanding hematoma within a perichondrial pocket enhances absorption.

-infection puts cartilage at increased risk for resorption.

-If septal hematoma remains uninfected, the clot proceeds to liquefaction.

Partial or complete resorption of hematoma ensues +/- fibrosis Þ permanent thickening of septum

-If septal hematoma becomes infected Þ substantial if not total cartilaginous absorption follows.

Þ classic saddle deformity, due to loss of septal structure & scar contracture.

-causes: -failure to adequately obliterate intramembranous dead space

-bleeding from bone edges in floor.

-clin: -swelling and pain. (nb: intense pain does not occur after septoplasty; if it does, ??hematoma)

-excessive swelling of upper lip and mucosal discoloration under the upper lip.(results from intramembranous blood collection and subsequent dissection into tissues adjacent)

-complete nasal obstruction.

-Mx: -prompt.

-drainage through previously made transfixion incision +/-drain.

nb: Needle aspiration of localized pockets of partially clotted blood may be adequate) -following evacuation Þ intranasal packing and antibiotics.

Infection

-infection following septoplasty is unusual.

Nasal obstruction

-after postoperative swelling has subsided, continued nasal obstruction is usually related to:

scar formation (adhesions) or turbinate hypertrophy.

-scar bands are usually small and can be corrected in the office with LA and transection.

-nb: the compensatory pre-op hypertrophy of inf or mid turbinate on concave side of septum, can be a

problem post op if not Rx’d at Sx.

Septal perforation

-When tears occur bilaterally and opposite one another, potential for postop septal perforation exists.

-Under such circumstances, reapproximate mucosal edges with sutures on at least one side & place a

piece of intervening cartilage between the membranes.

-Post-operative infection, excessive packing, hematoma, tight membrane-approximation sutures

can Þ vascular compromise and subsequent septal perforation.

Palatal and dental anesthesia

Clin: temporary anesthesia of medial incisor teeth & immediately adjacent palatal mucosa.

Due to: transection of delicate nerve endings in area of premaxilla

This anesthesia is usually short lived.

Anosmia

Alteration in ability to smell has been reported but is very unusual.

Cosmetic nasal deformity

-following excessive removal of nasal septal cartilage.

-When removal of substantial amounts of septal cartilage is necessary, every attempt should be made

to place straightened cartilage back into the surgically created dead space.

Bibliography:

Cottle M: Nasal surgery in children: effect of early nasal injury, EENT Monthly 30:32, 1951.

Cottle M: Concepts of nasal physiology as related to nasal surgery, Arch Otolaryngol 72:11, 1960.

Cottle M, Loring R: Corrective surgery of the external nasal pyramid and the nasal septum for restoration of normal physiology, EENT Monthly 26:147, 1947.

Cummings, C. Otolaryngology. 

Gates G, Current Therapeutics.