NASAL OBSTRUCTION DUE TO RESTRICTION OF THE BONY NASAL INLET By LEo ROZNER, F.R.C.S., F.R.A.C.S. Senior Registrar, Plastic and Jaw Department, United Sheffield Hospitals THE plastic surgeon is concerned primarily with the appearance of the nose, but is often confronted with problems of function before or after correcting a nasal deformity. Although the nose is a complex organ with many physiological functions such as filtration, humidification, and olfaction, they all depend on an adequate flow of air through the nasal cavity. Thus when function is considered the surgeon is in fact concerned with the mechanics of air flow, and his treatment should aim at its improvement. In general terms, the space available for the passage of air through the nasal fossa is determined by the size of the cavity demarcated by the bony walls, minus the volume taken up by the intranasal structures. A procedure to relieve nasal obstruction can therefore be aimed at reducing the nasal contents, or at increasing the capacity of the conduit. The first serious attempts to overcome nasal obstruction were directed towards correction of septal deformities, either by excision (Langenbeck, I843; Dieffenbach, I845 ) or by repositioning the septum and holding it in the midline with nasal packs (Adams, I875 ; Asch, I89I). While subsequent literature offers innumerable technical variations, this basic approach of trying to obtain airways of equal size by centralising the septum remains unaltered to the present time. The profuse, and at times contradictory advice, is aimed at reducing the technical difficulties, uncertain results, and hazards of anterior septal correction, but does not help to establish the fundamental definition of what constitutes a " septal deformity." The latter may be the predominant difficulty as the majority of normal people when carefully examined, are found to have a deviated septum, and despite significant inequality of the airways to have no complaints related to nasal function and give no history of trauma. This suggests that although the septal position may have a profound influence on the appearance of the nose it is not of the same importance in nasal function. Nasal obstruction due to any of a number of other intranasal abnormalities is widely acknowledged, but nasal insufficiency due to restriction of the bony cavity, particularly the inlet, is less well recognised though it is in fact not rare (Douglas, I952). In this communication some of the anatomical factors which influence the passage of air through the nose will be considered. Special reference will be made to anterior nasal obstruction resulting from bony restriction at the nasal inlet, and its relief by operative procedures which increase the total capacity of the anterior nasal airway. Anatomy and Physiology of the External Nose.--The external nose is usually considered to be the part anterior to a vertical plane passing through the glabella. This arbitrary division separates two portions of the nasal fossa which differ in many ways, e.g., size, shape, rigidity, and configuration of the walls. The anterior nose is the shape of half a hollow pyramid cut on a diagonal (Fig. I). The apex is at the glabella, and the dorsum, equivalent to the edge 287
288 BRITISH JOURNAL OF PLASTIC SURGERY between the two lateral walls, ends at the rounded tip. The base has the ovoid nares through which the air enters. The internal shape is thus of two funnels, ~ one on each side of the septum, which narrow LABELLA from the nares to the root of the nose, but expand as they proceed backwards to continue into the posterior nose at the glabellar plane. The relatively rigid and resistant cartilaginous septum supports the dorsum and influences the shape and position of the external nose. But to function as a support it is by no means necessary NARES for the septum to be straight or in the midline. Its loss as by a radical submucous resection or FI~. i following trauma, allows the part of the nose Nasal pyramid from behind. below the bony bridge to collapse. This change in shape alters the direction of air inflow and allows the redundant septum to bulge into and narrow the airways. Both factors contribute to the nasal insufficiency which is often noticed. The upper part of the lateral wall is rigid, being formed by the nasal bones and part of the frontal processes of the maxillm. They follow the inclination of the walls of the pyramid, running downwards and inwards to the dorsum. The //1~ \\\\. \ \ A B FIG. 2 A, Effect of bone length on the size of the nasal inlet. B, " Plan " of the anterior nose showing aperture size varying with the length and inclination of the bony walls. free lower edges of these bones form the boundaries of the anterior nasal aperture and are readily displayed as a ridge under the stretched nasal lining. It has been suggested that in the normal nose the ridge can act as "one of the baffles which slows and directs the entering air currents " (Cottle, 1955). The size of the aperture varies not only with the height and breadth of the nose, but with the length of the bones and their inclination to the midline (Fig. 2). The further they extend towards the tip and/or the more obtuse the angle, the less the cross-sectional area of the anterior nasal opening becomes. It is conceivable that the bony growth during development could leave an aperture which is too small to allow sufficient air flow for the person's needs during all activities.
NASAL OBSTRUCTION 289 The lower part of the lateral wall is mobile and consists of resilient lateral cartilages which are mainly attached to the septal cartilage and imbedded in fibro-fatty tissue. It can be moved passively by finger or air pressure as when a sharp sniff draws it inwards narrowing the nostrils ; or actively, when opened or steadied by muscular action in dyspnoea, taking a deep sigh, and during speech. By merely lifting the tip of the normal nose air inflow becomes easier--probably due to straightening out the airway rather than changing the capacity of the nose. This part appears to direct the air stream, and to have a valvular function which plays a part in phonation. Singers are aware of this and train in nasal control. The flow per unit time through the funnel which directs the air to the respiratory part of the nose (after coarse filtration by the vibrissm) is determined by the resistance in the passages, being greatest at the narrowest part of the conduit. Although the nares at rest have the smallest cross-sectional diameter, their size varies during activity. The narrowest rigid part of this air channel occurs between the free ends of the bones and the septum. Small changes in diameter at this site have very significant effects on the resistance. For turbulent gas flow the resistance factor varies as I/D 4 (+50 per cent.). Therefore a IO mm. diameter's resistance factor is 1/6666. Reducing the diameter by only 2 ram. increases it to 1/2733, i.e., two and a half times ; all other factors remaining equal. The ability to relieve the blocked nose in coryza by reducing the swelling of the mucous membrane a millimetre or so with decongestant drops is a practical example of how minor changes in diameter can radically alter the air flow through the nose. Causes of Restriction of the Bony Nasal Inlet.--Sometimes the clinical diagnosis of obstruction is difficult, for it is determined to an extent by the patient's subjective feelings over his whole range of activity. While some are content with an airway reduced to a mere slit, others complain bitterly about passages which appear to be more than adequate. Even the crude but widely used " Sniff Test" may show vast differences in the ease of air passage through the nose in consecutive examinations and not indicate the true state of affairs. Although an individual variation in " nose consciousness " needs to be taken into account, the deciding factor may be the maximum air flow which can pass through the nasal cavity in relation to the patient's needs. Bearing these difficulties in mind, IOO treated nasal fractures of all degrees of severity were reviewed at least six months after the injury. Thirty-five were considered to have been left with some restriction of the airway, on the basis of the detailed history, careful clinical examination, and repeated " sniff tests " (see table). ~, As a control, fifty patients with neither complaints related to the nose nor history of trauma were examined. Thirty-four had a deviated septum producing significant inequality of air flow between the two sides as determined by the " sniff test" and confirmed by the patient finding that greatly different force was required to drive the air through each nostril. It follows that without knowledge of the septal state prior to the accident it is difficult to be sure that the trauma is responsible for any individual septal deviation. It is likely that in some instances the septum had previously been eccentric and neither the accidental nor the manipulative forces had changed its position or degree of deviation. It is not always realised that in some of the 3 F
290 BRITISH JOURNAL OF PLASTIC SURGERY Group 4 cases, just as in all the Group 3, obstruction could be due to a change in the position of the lateral wall rather than to a displacement of the septum. There are cases of anterior nasal obstruction either following trauma or from other causes, where the appearance of the nose is acceptable. Unless some other cause such as a polyp or soft tissue stricture is found this type of case often tends to be treated by the same septal procedures which are used for straightening a deviated nose. Although in the majority it is effective, in a significant percentage placing the septum in the midline does not give the desired increased air flow ; and a few are in fact made worse. TABLE Cause of the Obstruction I. Deviated septum only 2. Enlarged inferior turbinate 3. Malreduced bony wall. Septum midline 4. Malreduced bony wall. Septum deviated also Complaining only of Obstruction Complaining equally of Obstruction and Appearance Irregularity of Bridge o o I Saddle I o o 6 3 Deviation Total I5 20 In these cases of anterior nasal obstruction where the septum can no longer be at fault, and possibly in most cases where the appearance is acceptable, attention should be focused on the lateral wall. It may be recalled that the total air flow depends on the capacity of the anterior nose at its narrowest rigid diameter, and that it could be too small for the patient's needs. Often the free bony margins of the lateral wall, which form the main part of the rigid inlet, may be seen to protrude excessively into the nostril and encroach on the airway. Anterior nasal obstruction due to stenosis of the bony inlet thus may be : x. Traumatic, where the inlet is narrowed by mal-reduced indriven bony fragments of the lateral wall. 2. Developmental, where there is no obvious bony displacement, but an aperture which is too small for the patient's needs remains after the growth of the bones of the nasal pyramid. Management of Stenosis of the Bony Nasal Inlet.--Traumatic Stenosis.-- This type of stenosis may result either from redisplacement of an unstable fracture spontaneously or inadvertently while applying external fixation, or because of imperfect reduction at the original manipulation. When oedema of the soft tissues over the recently fractured bones makes it difficult to palpate them accurately, the bones on the inner surface of the lateral wall may still remain displaced into the nostril whilst the skin contour of the nose appears satisfactory. In either case the deformity is revealed when the plaster is removed and the (edema has settled.
NASAL OBSTRUCTION 291 The principal features are due to the position of the displaced bones-- asymmetrical appearance, a " step " at the side of the bridge, and intranasal FIG. 3 Case I. On presentation eight months after the injury. A, Bony fragments on the left side displaced into the airway. B, Lateral view with fracture lines still obvious. C, Capacity of the normal right nostril. D~ Malreduced fragments presenting into and restricting the left airway. prominence (with a more vertical inclination) of the bony margin which reduces the capacity of the nostril. Although minor deformities of this type can be ignored, some patients complain that the nose is "bent," "humped," and/or "blocked." When indicated, correction can be undertaken by manipulation
292 BRITISH JOURNAL OF PLASTIC SURGERY using Walsham's forceps applied with moderate but sustained force. The fragments should be accurately placed into slight over-correction and supported with a firm nasal pack for seventy-two hours. A plaster splint laid on with minimum moulding pressure protects the nose for ten days. The manipulation permanently restores the capacity of the obstructed airway to its pre-traumatic state. The widely held belief that nasal fractures unite rapidly may be true of fractures through the thick part of the maxillary bone at the base of the nose, but it does not appear to be so for fractures through the thin bony plates (nasal and adjacent frontal processes of the maxilla) which constitute most of the lateral wall. The clinical evidence of fibrous union, indicated by some tenderness and slight mobility of the fragments, is supported by X-rays showing clearly visible fracture lines many months after the accident ; and fragments of the bony wall have been found to be still mobile at corrective rhinoplasties undertaken many months after the injury. Similar FIG. 4 observations about the slow union of nasal fractures Case I. One month after and the feasibility of achieving permanent and manipulation, satisfactory correction by late manipulation have previously been recorded (Rubinstein, 1956; Crawford, 1963) with the suggestion that if the fracture cannot be reduced immediately, better results may be obtained if the oedema is allowed to settle before undertaking the correction. Case I.--Mr A. A., aged 27. This man had no complaints relating to nasal function prior to July 1962, when he sustained a lateral violence fracture of the nose in a fight. The nasal pyramid was displaced to the right and considerable swelling developed. The left nasal bones were driven inwards and the right slightly outwards. The fracture was easily manipulated, reducing with a palpable " click." No nasal packs were inserted, but the fragments were immobilised for a week by a plaster of Paris splint. He returned eight months later complaining principally of left-sided obstruction and also of the deformity. Examination showed an apparent deviation of the nose due to some inward displacement of the left side. The right side and bridge were in their normal position, despite the impression of deviation. Palpation revealed a step on the left side of the bridge and some tenderness and slight mobility of the displaced bones. Their lower edges presented, and were more vertically inclined, inside the left nostril (Fig. B)- As the septum was also slightly deviated to the left, this airway was much smaller than the right. Under endotracheal anmsthesia the left nasal fragments were manipulated into slight over-correction, the nostril packed, and a plaster laid on with minimal moulding pressure. The packs were removed after three days and the plaster after ten days. One month later the patient reported that the airway was restored to normal and the appearance much improved (Fig. 4). Developmental Stenosis.--The feature of this group is the long-standing severe nasal obstruction which has not improved despite a number of operations on the septum and turbinates. Trauma is not a factor as any injury that may have
NASAL OBSTRUCTION 293 been sustained was usually minor, and the bones are seen at operation to be smooth and without evidence of old fracture. The bony nose is usually found to be small, or high-vaulted and narrow. Intranasally, the bony margins of the anterior aperture are prominent and near to the septum, radically reducing the airway. Fro. 5 A, Anterior bony aperture displayed at operation. B, Soft tissue elevated to expose the bony edge of the inlet. C, Post-operative radiograph of nasal inlet. D, Corresponding diagram of site and amount excised. Although there is some collapse of the lower part of the nose, the patient is referred for a bridge graft to elevate the nasal tip as a means of relieving the airway, rather than because there is any dissatisfaction with the appearance. By resecting some bone from the nasal inlet the capacity is increased, and the relief of obstruction is immediately noted by the patient. Douglas (I95~), after describing an application of this principle in which some of the maxilla only is resected from the nasal inlet,
294 BRITISH JOURNAL OF PLASTIC SURGERY states that "... partial resection of an unimportant portion of the superior maxilla submucously seems to provide a relatively simple and safe procedure for increasing the calibre of the airway and is to be preferred." Operative Details,--Under endotracheal anazsthesia, the capacity of the nostril is first tested by attempting to pass an obturator such as a length of stiff rubber tubing about I½ to 2 cm. external diameter. After the anterior bony margin is exposed through a nasal speculum and the area infiltrated with a few millilitres of I/IO,OOO adrenaline solution, a vertical incision is made through the lining and periosteum directly over the lower three-quarters of the presenting bony ridge. Over the whole length of the incision the soft tissue is elevated from both sides of the bone for about IO mm. with a dental scaler (Fig. 5). Starting at the maxillary end, about 5 ram. of the bony edge is removed. This can usually be done with a bone nibbler, though it may be necessary to start with horizontal chisel cuts in two or three places. Similar amounts are removed from the whole length of the cleared rim, but as the bone nearer the bridge is more fragile extra care is required to avoid splintering. The amount removed can be ascertained by putting the little finger into the nose and pressing through the overlying skin. The clearance is checked by passing the same obturator. If it "falls in " easily the airway will be adequate, but should it be held up at a particular point further trimming of the lateral wall may be undertaken~ Disappointing results are nearly always due to a conservative excision, and it is better to aim at slight overcorrection even if it requires a larger excision than the average 5 mm., particularly over the maxilla. The incision is closed with one No. ooo chromic catgut suture, and the dead space and oozing controlled by packing the nostril firmly with tulle gras and applying counter pressure with dental rolls and elastic strapping. On removing the packs in forty-eight hours the patient immediately notices the improvement in the airway, though it may subsequently retrogress with the reactionary oedema. Slight tenderness and Gedema over the nose settles in about three weeks, and the airway reaches maximum improvement in about six weeks. In review six months after this procedure, there has been no noticeable akeration in nasal appearance. Case 2.--Mrs J. Y., aged 57. This patient had some negroid features including a rather small flat bony nose and flaring nostrils. In early childhood she had sustained a nasal injury, but could not recall any details of the accident or of treatment. As long as she could remember she had had equal difficulty in nasal breathing on both sides. She was inclined to be a mouth breather on the slightest exertion, very prone to " colds," and to snore. In 1958 she had a submucous resection, following which the lower part of her nose drooped and became broader. Although she was not particularly concerned with the shape of her nose, as it drooped the obstruction worsened until it was virtually complete on both sides. In 196o, diathermy destruction of the inferior turbinates did not give any improvement. In 1962 she was referred for a graft to elevate the nasal bridge. On examination the bony nose was midline and symmetrical, but the lower part was saddled, the tip drooped, and the nostrils were wide and flaring. The septum was broadened and bulged into the airways. Part of the inferior turbinates were still visible but not enlarged. The bony margins of the lateral walls were prominent inside the nose, leaving a slit of about 4 mm. between the septum and the bony inlet on each side. Relief,of obstruction was obtained by lifting up the tip or pulling the lateral wall outwards. At operation the bone was found to be smooth with no evidence of previous injury.
NASAL OBSTRUCTION 295 About 5 mm. was resected from each pyriform margin and a x½ cm. obturator could then be passed with ease. Three months later the patient reported that the airways were clearer than she could ever remember, and that there had been no change in nasal shape. DISCUSSION Before undertaking the treatment of any problem following accidental or surgical trauma to the external nose, the surgeon should be absolutely clear as to what he wishes to achieve. If the nose requires cosmetic improvement septal correction may form an essential part of the plan of treatment. Not only is it necessary for repositioning and retention of the osteotomy fragments, but as the nose is narrowed any unsuccessfully corrected septal spurs or deviations will further restrict the airway. If the shape is acceptable but the object is to improve nasal function the operation must increase the air flow through the nose. Moving a deviated septum within the finite space of the bony nose can enlarge the narrowed airway only by a commensurate restriction of the other side, and will not alter the total nasal air flow. Clinically, cases are seen in which the air flow is insufficient for the patient's needs despite a septum which has remained, or has been replaced in the midline. Taken in conjunction with the findings in the control group, it suggests that a deviation should not automatically be taken as the cause of obstruction, or that septal operations will relieve it. The recognition that the bony margin of the anterior nasal inlet can affect the total air flow has thrown light on some of the problems of nasal obstruction. Improvement of the airway by attacking the cause and site of maximal restriction only, follows logically. Both procedures described for the relief of anterior choanal stenosis conform to all the requirements for increasing total nasal function. To increase the diameter by replacing the real-reduced fragments follows surgical principles. To increase the diameter by resecting a small part of the free edge of the lateral wall follows an understanding of the anatomical shape of the anterior nose. The operations are quick, simple, and economical of hospital accommodation. By lateral wall excision, the permanent correction achieved can be accurately gauged since the parts cannot slip back. The nasal shape does not alter as the bridge support is not weakened or even approached, and the resilience of the lateral cartilage, firmly attached to the septum, has a tendency to hold the nostrils open. As already indicated, in cases of nasal collapse due to loss of septal support with recurrent obstruction but in which the appearance is acceptable, this direct attack at the site of obstruction has the advantage of not only giving permanent relief but eliminating the problems of grafting. The procedure does not prejudice the subsequent performance of any other operation--including infracture--and therefore can have a wider application. For example, in difficult borderline cases where the surgeon may be reluctant to undertake what amounts to a major operation, a resection at the pyriform margin could be used as a therapeutic test. In the presence of gross septal deformity which would require the operator to be so radical as consciously to risk nasal collapse to get the necessary functional improvement, a partial septal resection combined with bony resection of the adjacent lateral wall can give the desired capacity without altering the nasal shape.
2~6: BRITISH JOURNAL OF PLASTIC SURGERY The subject remains fraught with difficulties and many basic problems await elucidation. Without the development of a precise clinical method of measuring nasal function it cannot be taken that one approach to the relief of nasal obstruction is better than any other. A procedure which is simple and appears to give satisfactory results is, however, at least worthy of further consideration and perhaps addition to the armamentarium, either alone or with a less radical septal procedure, for those selected cases of obstruction of the anterior nose where the lesion can be localised to the region of the anterior choanm. I should like to record my gratitude to the Consultant Surgeons of this Department, Mr W. Hynes, Mr B. S. Crawford and Mr D. A. Campbell Reid, who so kindly allowed me to treat and review cases under their care ; and for their helpful advice and constructive criticism during the preparation of this paper. Mr A. S. Foster, Medical Artist to the United Sheffield Hospitals, is responsible for the very fine drawings ; and Miss S. W. Spence, of the Photographic Department of the Sheffield Royal Hospital, for the photographs which speak for themselves. REFERENCES ADAMS, G. (1875). Brit. med. J., 2, 421. ASCH, M. (1891). " A New Operation for Deviation of the Nasal Septum, with a Report of Cases. Trans. Amer. Laryng. Ass., p. 76. D. Appleton & Co. COTTLE, M. H. (1955). Arch. Otolaryng., 62, 173. CRAWFORD, B. S. (1963). Brit. ft. plast. Surg., x6, 23I. DIEFFENBACH, J. (I845). " Die operative Chirurgie." Leipzig. DOUGLAS, B. (1952). Plast. reconstr. Surg., 9, 42. LANGENBECK, B. (1843). " Handbuch der Anatomie." G6ttingen. RUBINSTEIN, M. (1956). Arch. Otolaryng., 6a, 355. Submitted for publication, August 1963.