Nasal obstruction is one of the most common complaints to otolaryngologists. The aetiology of this particular symptom is complex and a number of differential diagnoses, often multifactorial, can arise. The most common causes of nasal obstruction are nasal valve stenosis or collapse and those problems are frequently the result of previous rhinoplasty. According to studies, 72% of the patients with nasal valve obstruction had previous rhinoplasty (Elwany and Thabet 1996). Following a rhinoplasty, the internal nasal valve area may decrease as much as 25% of the preoperative value (Grymer 1995). Reductive rhinoplasty, by its nature, removes portions of the bony and cartilaginous support of the nasal airway. Preoperative obstruction may also be present in some patients and if not recognised can be made worse after rhinoplasty. In management of a post-rhinoplasty middle nasal vault deformity, the spreader graft (Sheen 1984) has become the standard technique to repair the nasal airway. The spreader graft was first described by Sheen in 1984 as a method of reconstructing the internal nasal valve and recreating the dorsal aesthetic lines. The graft acts as a spacer between the upper lateral cartilage and septum, this widens the nasal valve angle and thus relieve the obstruction.
Anatomy of the middle nasal vault
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The middle nasal vault, also known as the cartilaginous nasal vault is composed primarily of upper lateral cartilages, nasal septum and investing soft tissue. A T or Y shape is formed by the nasal septum along the midpoint of the middle vault where it connects with the upper lateral cartilages (Figure 1). The upper lateral cartilages extend away from the dorsal margin of the septum and then curve toward the pyriform aperture. This forms the trapezoid shape of the middle nasal vault (Figure 1).
Figure 1. Left, shows the cross-section view through the middle vault. On the right is a cadaveric specimen of a cross-section of middle nasal vault taken through similar point. (Picture adapted from Toriumi 1995)
The dorsal side of the middle nasal vault narrows from the osseocartilaginous junction to the anterior septal angle. The internal nasal valve is made of the caudal margin of the upper lateral cartilage, nasal septum, and floor of the nose. The junction between the caudal margin of the upper lateral cartilage and the septum form the nasal valve angle, which is usually 10ï‚° to 20ï‚° (Figure 2). The nasal valve area is the narrowest portion of the upper respiratory tract and has been deemed the main site of nasal resistance. According to Poiseuille's law, airflow through the nose is proportional to the radius of the airway raised to the fourth power. Any small deflection of the septum or the upper lateral cartilages can lead to exponential decrease in airflow. According to the Bernoulli principle, the intraluminal pressure decreases as airflow increases through the valve. If the lateral nasal wall is weakened, this drop in intraluminal pressure can cause collapse of the nasal wall. Any damage to the structural integrity to the nasal valve can lead to collapse and airway obstruction, therefore it is critical that the function of the nasal valve is maintained following rhinoplasty.
Figure 2. Sketch on the left shows a cross section through the internal nasal valve. The cadaveric specimen on the right showing the caudal margin of upper lateral cartilages meeting the septum. The junction between the upper lateral cartilages and the septum at the internal nasal valve is known as the valve angle, in this specimen is approximately 15ï‚°. (Adapted from Toriumi 1995)
While there are many different procedures in dealing with narrowed or collapsed nasal valve, the most widely performed is the spreader graft (Figure 3). Spreader grafts are rectangular cartilage grafts placed between the upper lateral cartilages and dorsal margin of the septum (Sheen 1984). The grafts can be harvested from septal cartilage and should measure 1 to 4 mm in thickness (Toriumi and Johnson1993). 1 to 2 mm thick grafts can be used to preserve width of the middle vault after hump removal; 2 to 4 mm thick grafts are used to increase the width of the middle nasal vault. To make thicker grafts, two layers of septal cartilage can be sutured together with a 5-0 PDS mattress suture (Toriumi 1995).
The height of the grafts should be 3 to 6 mm so they do not affect the airway and the length can range from 8 to 25 mm (Toriumi 1995). The grafts are mostly 10 to 18 mm in length and extend from the osseocartilaginous junction to a point just caudal to the anterior septal angle. As the grafts approach the anterior septal angle, they should taper in thickness to prevent lateral displacement of the lateral crura(Toriumi 1995). Longer and stiffer spreader grafts can be used to correct deviations or weakness in the dorsal margin of the septal cartilage (Zijlker and Vuyk 1993).
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Figure 3. Bilateral spreader grafts have been placed in this patient to open the internal nasal valves and widen the middle nasal vault. (Adapted from Stacey et al 2009.)
Spreader grafts can be placed with endonasal or open rhinoplasty approach. The closed approach requires positioning the graft without direct visualisation and a long and narrow subperichondral pocket need to be dissected for graft placement (Sheen 1984). If possible, the graft should be inserted in this pocket to avoid disruption of the upper lateral cartilages from the septum.
Figure 4. Bilateral mucoperichondrial flaps are elevated to the junction between the upper lateral cartilages and the septum. This dissection allows the upper lateral cartilages to be sharply divided from the septum without disrupting the mucoperichondrium. (Adapted from Toriumi 1995)
In open procedures, a septoplasty is usually performed to correct deformities of the septum and this also produce the cartilage for grafting (Johnson and Toriumi 1990). During septoplasty, a hemitransfixion incision is made at the caudal margin of the septum, and bilateral mucoperichondrial flaps are elevated up to the junction between the upper lateral cartilages and septum (Toriumi and Johnson1993, see figure 4). Preservation of the mucoperichondrium is important because it will provide support to the graft and prevent collapse. Disruption of the intranasal mucosa can result in loss of medial support and inferomedial collapse of the upper later cartilages (Constantian 1993, Figure 5 and 6).
Figure 5. Hump reduction of the middle vault. When the intranasal mucoperichondrium is intact, the upper lateral cartilages are partially supported preventing collapse. (A) Intranasal mucosa is partially dissected away from the septum and the upper lateral cartilages. (B) Open roof with intact mucosa. (C) Minimal movement of the upper lateral cartilages with no compromise to the airway. (Adapted from Toriumi 1995)
Next, the upper lateral cartilages are divided from the septum using a Freer elevator inserted into the hemitransfixion incision, this exposes the middle vault. Then the upper lateral cartilages are dissected off the septum from the osseocartilaginous junction to the anterior septal angle, this will provide good visualisation of the dorsal margin of the nasal septum.
Once the upper lateral cartilages are free from the septum, the spreader grafts can be fixed directly to the septum. Both grafts can be initially sutured directly to the dorsal margin of the septum and then the caudal margin of the upper lateral cartilages should be sutured back to the septum (Toriumi 1995).
Figure 6. Hump reduction of the middle vault, to illustrate the importance of the intranasal mucosa support. (A) Hump is removed with intranasal mucosa. (B) Open roof with no mucosal support. (C) Inferomedial collapse of the upper lateral cartilages with compromise of the airway. (Adapted from Toriumi 1995)
The middle vault may appear slightly wide after the grafts are sutured into position, this is caused by oedema and will resolve in time. Plus, the scar contracture will also pull the upper lateral cartilages medially. In some cases, irregularities occur on the dorsal margin of the septum after spreader graft when the oedema resolve. This can be caused by grafts protruding above the dorsal margin of the septum. To prevent this, a thin graft can be placed over the dorsum of the nose to cover the spreader grafts and conceal visible deformities.
Endoscopic placement of spreader grafts
While the open procedure of placing spread grafts has many advantages over the closed one, it also causes extensive disruption of normal tissues and sometimes a columellar scar. Huang et al conducted a study using cadaveric heads to evaluate the possibility of placing the spreader graft using the endoscopic technique.
The study was done on cadaveric heads and one side of the head is randomly selected for grafting and the contralateral side is used as control. On the chosen side a standard hemitransfixion incision was made and a submucoperichondrial septal flap was then elevated. After the submucosal space was prepared, a 30-degree nasal rigid endoscope was inserted to visualise the nasal valve. Under the endoscopic guidance the graft was sandwiched between the septum and the upper lateral cartilage and septal flap was the restored to its normal position (Huang et al 2006).
Results shown there is an average net increase in nasal valve cross-sectional area of 0.280cm2 on the operated side, and this is statistically significant change compared to the control side. On external transcutaneous inspections, all grafts were confirmed to be in the proper position (Huang et al 2006). Objective testing of nasal function is typically performed with acoustic rhinometry, which is used in this experiment. Subjective evaluation using patient grading or objective flow rate measurements cannot be obtain on cadavers, so direct comparison between the endoscopic and the standard open techniques is not available. Furthermore, the same graft harvested from a cadaveric septal cartilage was used in all specimens. I think this over simplified the spreader graft procedure which usually involves obtaining the graft material from the patient. Most graft material for spreader graft is obtained from the nasal septum, using the endoscopic approach this could become more difficult so materials from a different site may need to be considered.
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Nonetheless, this study showed that the endoscopic technique is a viable and possibility better method of placing spreader grafts. Endoscope can provide great visualisation, illumination and magnification of nasal valve region, but it does make suture fixation difficult. The practicality of the endoscopic approach is yet to be proven and it should be fully evaluated in real clinical settings.
The ideal graft material is yet to be discovered. Cartilage autografts, when properly harvested and handled, are perhaps the closest to the perfect candidate. It is the most frequently used in rhinoplasty, because the autologous cartilages are durable and versatile and is not rejected by the host (Tardy 1997).
Some patients undergoing spreader graft operation may not have usable donor septal cartilage or may require more donor cartilage than their septum can provide. For those patients the auricular cartilage can be used instead (Murrell 2004). The complication rate is low at 5% and none of which was judged to be serious, but all patients would have a scar on the anterior side of the ear chosen to be harvested (Figure 7, Murrell 2004).
Figure 7. Follow up pictures of three separate cases showing scar left after the cartilage harvest. Left: 30 months postoperative appearance of the donor site of a 6-year-old female showing favourable results. Middle: 12 months postoperative of a 45-year-old female showing favourable healing. Right: donor site of a 41-year-old black male shows favourable healing at 14 months postoperative. (Adapted from Murrell 2004)
Addition to auricular cartilage, bone grafts obtained from the mental symphysis can also be considered in septal cartilage depleted patients (Prado et al 2008). Additional instruments are required to harvest the bone graft: hand oscillating saw, sharp osteotomes and a Tessier bone modulator for straightening the bone (Prado et al 2008). When the cancellous side of the bone is contacting the septum, it acts as an auto-blocking fixation with no need of suturing (Prado et al 2008).
Groups prone to collapse of the nasal valve after primary rhinoplasty
Certain patients indicated for primary rhinoplasty are at greater risk of postoperative complications due to the presence of specific anatomical characteristics. "Narrow nose syndrome" patients are predisposed to collapse of the cartilaginous vault following hump excision. This syndrome was first described by Sheen (Sheen 1984) and those patients have a combination of short nasal bones, long and weak upper lateral cartilages and thin skin.
Patients with short nasal bones will not adequately support the relatively long middle vault. If the surgeon resects and dorsum without reconstructing the roof to provide width to the anterior dorsal edge, the patient will suffer impaired function and the nose will appear caved in (Sheen 1984). Patients with thin skin on the nose will also suffer from collapse of the lateral walls following dorsal resection and result in a caved-in appearance (Sheen 1984). After resection of the roof, the upper lateral cartilages are no longer held away from the septum by the broad dorsal edge, flaccid cartilages will droop medially and narrowing the middle vault (Sheen 1984).
Spreader graft should also be considered during primary rhinoplasty with patients displaying a disproportion in width between the middle nasal vault and the nasal tip (Toriumi 1995). This disproportion causes disharmony of the line from brow to nasal tip and may lead to surgeons to narrow the tip excessively to make it proportional to the narrow middle nasal vault. This aggressive procedure can produce unsatisfactory aesthetic results and also impair the function of the external nasal valve (Boccieri et al 2005). The bilateral placement of spreader grafts makes it possible to harmonise the line from eyebrow to nasal tip and to use less aggressive surgical procedures on the tip itself (Boccieri et al 2005).
Patients of crooked nose are another group might benefit from spreader grafts (Boccieri 2005). Risk of reoccurrence and collapse of the middle nasal vault is often high after crooked nose correction. The cartilage memory of the nasal septum and the extrinsic forces exerted by the upper lateral cartilages tend to bring the septum back to its original, deviated position (Boccieri 2005). The use of unilateral spreader graft performs the dual function of strengthening and supporting the structure while countering cartilage memory (Boccieri 2005).
Variations on the spreader graft
Apart from spreader graft, there are also other techniques that can be used to reconstruct the nasal valve area. One of which is to used upper lateral cartilages as "spreader flaps" (Ozmen et al 2008). The upper lateral cartilages are separated from the septum, the superomedial parts of the upper lateral cartilages are detached from their attachments to the medial aspects of the nasal bones; the caudal and medial parts of the upper lateral cartilages are grasped with a Brown-Adson forceps and folded inward, toward the septum bilaterally (Figure 8, Ozmen et al 2008). The fold-in manoeuvre was performed before hump reduction to keep upper lateral cartilages away from trauma during hump reduction and it also helps to determine the amount of hump reduction (Ozmen et al 2008). After the hump reduction, the folded upper lateral cartilages are sutured to the dorsal septum (Figure 8).
Figure 8. Left, The caudal and middle parts of the upper lateral cartilages are grasped with a Brown-Adson forceps and folded inwards at both sides of the nasal septum. Right, the folded upper lateral cartilages are sutured to the dorsal septum with 5-0 polydioxanone sutures. (Adapted from Ozmen et al 2008)
The fold-in flap technique is an alternative method to preserve the aesthetic and functional features of the middle nasal vault without cartilaginous grafts. It is relative simple and proven to be effective (Ozmen et al 2009), the widening of the middle nasal vault is insignificant and no morbidity was produced.
Nasal valve collapse is a complex problem that requires a thorough history and physical examination to identify the specific sites involved in the obstruction. For long-term improvement, the general emphasis is to have less reduction and more augmentation. The spreader grafts can be used to reconstitute the support to the middle vault and correct impairments of the internal nasal valve. The use of spreader grafts in primary rhinoplasty has massively increased in prevalence since its first introduction. This is due to its proven usefulness and effectiveness in restoring middle nasal vault function through many years of experience by various surgeons. Originally, spreader grafts are only intended for "narrow nose syndrome" patients. Since then, many more anatomical variations of the nose are recognised to be at risk of middle nasal vault collapse, so the use of spread grafts will continue to expand. For patients with severe middle vault deformity, spreader grafts can be combined with dorsal onlay or columellar grafts (Arslan et al 2007). Spreader graft combined laser assisted uvuloplasty can be used to treat obstructive sleep apnoea (Cillo et al 2006), this technique is successful at improving quality of sleep and reduce daytime sleepiness. It is likely that the placement of spreader grafts will be done by using endoscopic technique, because this has became the preferred method to access the nose. This will reduce the amount of dissection required, reducing recovery time and visible scars and improving overall patient satisfaction.