"Is a CT scan really necessary for rhinoplasty?"
There are surely not a few people who feel this way. Considering the cost and trouble, it's a natural question.
To state the conclusion first, CT is not a "reassurance material"; it functions as a "design material" in rhinoplasty. Therefore, CT is not necessary for every case, and the judgment differs depending on the technique and purpose.
In this article, based on the latest clinical research, we explain the difference between cases where a CT scan is necessary for rhinoplasty and cases where it is unnecessary. Especially those consideringshort-nose correction or septal extension surgery, please use it as a reference.
Whether a CT scan is necessary for rhinoplasty: the judgment criteria you first want to know
In the preoperative evaluation of rhinoplasty, the cases where CT is considered especially effective are as follows.
- Wishing to correct the shortness of the nose (a short nose)
- Considering septal extension surgery (SEG)
- Planning to use one's own septal cartilage / bone
- Having had rhinoplasty in the past, with an unclear internal structure
On the other hand, in procedures that do not require detailed evaluation of bone and cartilage, such as adjusting the bridge height using only an implant, CT is not necessarily needed.
What is important is the sense of purpose of "taking it to obtain the information needed to decide the technique," not "taking it just in case."
Therefore, it is first important to confirm in a consultation with a physician which of these your case falls under.
The anatomical features of the Asian nose: what CT reveals
Rhinoplasty is not only an improvement of appearance; maintaining breathing function is also an important condition.
Therefore, accurately grasping the internal structure of the nose before surgery is required.
An indicator that should be especially noted is the "internal nasal valve (INV) angle," which receives the most air resistance in the nasal cavity.
By using CT, this angle can be precisely measured.
In addition, comparing data of Asians (centered on Koreans) and Westerners makes the anatomical differences clear.
As this data shows, the internal nasal valve angle of Asians is about twice as wide as that of Westerners.
Therefore, it has been found that Asians have an extremely low risk of "inverted-V deformity" even after hump excision.
In addition, the "spreader graft," considered standard in Western surgery, is not necessarily needed for many Asian patients.Confirming such anatomical differences before surgery with CT is important in appropriate technique selection.
The septal cartilage-bone complex (SCBC) as an option
The most common consultations in Asian rhinoplasty are "the shortness of the nose (a short nose)" and "insufficient tip height."
What solves these is "septal extension surgery (SEG)," but in cases where the Asian nose is small, there was a dilemma of not being able to secure a sufficient amount of cartilage for grafting.
Thus, what has attracted attention in recent years is SCBC (the septal cartilage-bone complex).
This is a technique that harvests bones such as the "perpendicular plate of the ethmoid (PPE)" and the "vomer" of the septum together with cartilage and reuses them as a firm strut.
Because it is completed with manipulation inside the nose alone, no additional incision to the ear or chest is needed.
In addition, by using bone together, structural stability that cannot be obtained with cartilage alone can be secured.
On the other hand, safety management is also very important.
To maintain the foundation of the nose, it is necessary to leave an "L-shaped maintenance structure (L-strut)" of at least 10 mm on the dorsal and caudal sides.
Therefore, procedures using SCBC are required to be performed under a specialist with advanced skill and abundant experience.
Also, because bone is hard, skilled techniques such as drilling fine holes with a drill for fixation are also needed.
Cases where CT is needed in rhinoplasty: prior evaluation of bone quality by HU value
What is most important in utilizing SCBC is the prediction of the "quality" of the bone to be grafted.
In the latest CBCT diagnosis, the "Hounsfield Unit (HU value)," which indicates tissue density, is used as an indicator.
In addition, to perform a standard evaluation independent of the machine, the "HU ratio," the density ratio of bone to cartilage, is the modern standard.
One of the major reasons CT is needed in rhinoplasty is precisely this preoperative bone-quality evaluation by HU ratio.
By grasping the state of the bone before surgery, the optimal technique and material can be selected.
- Bone optimal for surgery (equivalent to Type IV)
HU ratio: PPE 6.8 ± 2.1 / Vomer 5.7 ± 1.8
State: supple and easy to process, ideal as graft material. - Bone that is too hard / too thick (unsuitable)
HU ratio: PPE > 10.0 / Vomer > 7.0
State: as hard as bone thickness exceeding 3.6 mm, and may hinder delicate shaping. - Bone that is too brittle (unsuitable)
HU ratio: PPE < 4.0 / Vomer < 5.0
State: high risk of crumbling during harvesting or manipulation, and unsuitable.
By confirming the HU ratio before surgery, in cases where SCBC is judged unsuitable, alternative plans such as "irradiated homologous costal cartilage (IHCC)" or "auricular cartilage" can be prepared in advance.
Therefore, the point that "unforeseen situations" during surgery can be greatly reduced is a major reason CT scans are needed in rhinoplasty.
On the other hand, if it is found in advance that the bone quality is within the suitable range, there is also the merit of being able to omit the harvesting of additional material.
Thus, the role of CT is not "for reassurance" but "for optimizing the technique."
Results shown by clinical research and patient satisfaction
In a clinical study using SCBC (19 cases), the following results were reported regarding the change in appearance and patient satisfaction.
- Anatomical improvement (significant change)
Nose length: mean 3.90 mm → 4.85 mm
Tip projection: mean 2.21 mm → 2.71 mm - Satisfaction score (out of 10)
Shape: 8.1 points / tip height: 7.9 points / ease of breathing: 7.7 points
Softness of the tip: 5.9 points
Regarding the relatively low score for "softness," understanding from a professional perspective is important. This is a trade-off with the "structural stability" for reliably lengthening a short nose and preventing long-term reversion. Precisely because the strut is firm, the ideal height can be maintained.
In addition, the details of this studycan also be confirmed on PubMed (a medical literature database).
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Takeaways
- For Asian short noses, septal extension surgery with SCBC can be expected to yield aesthetically and functionally good results.
- The HU value obtained from CBCT is an effective indicator for predicting the quality of the bone to be grafted before surgery.
- Through preoperative evaluation using the HU ratio, an accurate surgical plan according to bone quality and advance preparation of alternative materials become possible.
- Whether a CT scan is necessary in rhinoplasty differs depending on the technique and case. Judgment in a precise consultation first is important.
What is most important in modern rhinoplasty is "agreement of the preoperative diagnosis."
Rather than noticing a material shortage after entering the operating room, knowing your own bone quality before surgery and selecting the optimal material.
That process is the shortest route to minimizing the risk of reoperation and to the ideal result.
In addition, related columns on rhinoplastycan also be viewed in the Zetith Beauty Clinic column list.
For a precise evaluation of rhinoplasty, please consult us first
"Is a CT scan necessary for my nose?" "What material is suitable for short-nose correction?"
Such questions can be confirmed one by one in a consultation. Whether a preoperative evaluation by CT is necessary will also be explained after an examination.
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References
- Seo M, Jung D. Predictive Evaluation of Septal Cartilage-bone Complex for Rhinoplasty Using Cone Beam Computed Tomography. Plastic and Reconstructive Surgery – Global Open. 2025. Confirm on PubMed
- Suh M, Jin H, Kim J. Computed tomography versus nasal endoscopy for the measurement of the internal nasal valve angle in Asians. Acta Oto-Laryngologica. 2008. Confirm on PubMed
The author of this article
Hiromitsu Nakamura Physician
Zetith Beauty Clinic Ginza / Osaka / Fukuoka
He has a track record of research presentations at domestic and international conferences in Japan and is also involved in technical guidance and education across the entire Zetith Beauty Clinic. Specializing in precise rhinoplasty based on anatomical grounds, he pursues natural results tailored to each individual's bone structure and tissue.