This work was funded by the National Nature Science Foundation of China for Young Scholars (No. 81300810), the Shanghai Young Doctor Training Program (No. 20141057), the Shanghai Natural Science Foundation (No. 16ZR1405100), and the Shanghai Municipal Commission of Health and Family Planning (No. 201740187). We would like to thank LetPub (www.letpub.com) for providing linguistic assistance during the preparation of this manuscript.

This procedure, which involved human subjects, was approved by the Institutional Review Board of the Eye and ENT Hospital, Fudan University, China. All the enrolled patients provided written informed consent.
1. Preparation for Surgery
<ol>
	<li>Before surgery, examine the patient&#39;s nasal cavity with anterior rhinoscopy, endoscopy, and computed tomography (CT) scans to confirm and locate the deviations and to identify the indications15.</li>
	<li>Ask the patient to assess the patency of their nose as a whole and to indicate this on a visual analog scale (VAS) before surgery. 
	NOTE: The total length of the scale was 10 cm, with one extreme being an entirely clear nose (i.e., 0 cm scoring 0%), the other extreme a completely blocked nose (10 cm scoring 100%), and the center a nose with a 50% blockage.</li>
	<li>Remove the vibrissae in both nasal vestibules 1 day before surgery.</li>
	<li>On the day of the surgery, administer general anesthesia to the patient after placing them on the operating table16. 
	NOTE: Induce anesthesia with 2 - 2.5 mg/kg of propofol, 0.2 &#181;g/kg of sulfentanyl, and 0.6 of mg/kg rocuronium. Maintain the anesthesia with a continuous intravenous infusion of remifentanil of 0.1 &#181;g/kg/min and an inhalation of sevoflurane (0.8 minimal alveolar concentration).</li>
	<li>Tilt the operating table 30&#176; (to the dorsal elevated position) and put the patient&#39;s head in a neutral position (neither flexed nor extended).</li>
</ol>
2. Surgical Procedure
NOTE: Use a 0-degree endoscope during the entire operation.
<ol>
	<li>Steep 8 pieces of gauze (6 cm x 60 cm) with a mixed solution of 20 mL of 1% tetracaine and 4 mL of 0.1% epinephrine. Put 1 soaked piece of gauze into each nasal cavity for 5 min to shrink the nasal mucosa.</li>
	<li>Put the inferior turbinate toward the lateral wall of the nasal cavity with the elevator at the end of the procedure.</li>
	<li>Infiltrate the septum using a needle attached to a 5 mL syringe with several milliliters of a mixed solution of 20 mL of 0.9% NaCl and 0.05 mL of 0.1% epinephrine in the subperichondrial and subperiosteal planes of both sides of the septum. 
	NOTE: If the septum was deviated to both sides, we defined the convex side as the side of the anterior deviation.</li>
	<li>Make a Killian incision at the mucocutaneous junction ipsilaterally on the side of the maximal deviation (i.e., the convex side) of the septal cartilage with a No. 15 blade. Start the vertical incision on the septum as high as possible, continue to the floor of the nasal cavity, and curve posteriorly as it reaches the floor of the nasal cavity. 
	NOTE: The incision needs to penetrate the mucous-perichondrium of the nasal septum.</li>
	<li>Raise the mucosal flap in the subperichondrial plane with the suction elevator in case of bleeding. Without bleeding, raise the flap with a 2 mm or 5 mm elevator. Extend the elevation as high as possible upwards and to the floor of the nasal cavity downwards to fully expose the cartilaginous and bony septum on the convex side.</li>
	<li>Make a vertical incision using the sharp end of the 2-mm elevator or a number 15 blade on the cartilage inferior to the dorsum and anterior to the junction of the quadrangular cartilage and perpendicular plate of the ethmoid bone (i.e., the first line of the 2LoRs). Likewise, make a horizontal incision on the cartilage superior to the junction of the quadrangular cartilage, vomer bone, and maxillary crest (i.e., the second line) (Figure 2A). 
	NOTE: In this way, the septal cartilage is mobilized from its posterior and inferior attachment to the bony septum, and the anterior and superior attachment is kept intact.</li>
	<li>Elevate the contralateral mucoperiosteum to expose the bony septum bilaterally with the suction elevator.</li>
	<li>Resect two strips of the posterior and inferior margins of the septal cartilage and the adjacent bony septum (Figure 1B).
	<ol>
		<li>Resect 1/4 to 1/3 (occasionally 1/3 to 1/2) of the original width of the cartilage in the anteroposterior dimension on the first line (Figure 2B).</li>
		<li>Resect 1/4 to 1/3 (occasionally 1/3 to 1/2) of the original height of the cartilage in the vertical dimension on the second line (Figure 2C).</li>
	</ol>
	</li>
	<li>Remove the thickening bony septal deviations and perform&#160;a partial fracture displacement to move the deviation back to the midline.&#160; 
	NOTE: The extensive removal of the posterior and inferior bony septum is to clear all of the thickness and deformities in this region.</li>
	<li>Control any intraoperative bleeding by electrocoagulation.</li>
	<li>Approximate the mucosal flaps by two interrupted sutures with absorbable materials (Figure 2D).
	<ol>
		<li>Start the sutures posterior to the incision, pass them through the septum to the opposite side, and then pull them back from the skin anterior to the incision site.</li>
		<li>Knot the sutures on themselves, respectively. Place the two sutures parallel, one above the other.</li>
	</ol>
	</li>
</ol>
3. Procedure and Assessment After Surgery
<ol>
	<li>Pack the nasal cavity with nasopore.</li>
	<li>Review the patient 1 week after the surgery to check if there is a hematoma or infection of the septum.</li>
	<li>Examine the nasal cavity with anterior rhinoscopy and 0-degree endoscopy and ask the patient to assess the patency of their nose with VAS 6 months after the surgery.</li>
	<li>Record postoperative septum hematoma, transient dental pain, hypesthesia, synechiae, epistaxis, septum abscess, septum swing, septal perforation, and dorsum collapse as surgical complications.</li>
</ol>

<ol>
	<li>Chung, B. J., Batra, P. S., Citardi, M. J., Lanza, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+septoplasty:+revisitation+of+the+technique,+indications,+and+outcomes.">Endoscopic septoplasty: revisitation of the technique, indications, and outcomes.</a> The American Journal of Rhinology. 21 (3), 307-311 (2007).</li><li>Hwang, P. H., McLaughlin, R. B., Lanza, D. C., Kennedy, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endoscopic+septoplasty:+indications,+technique,+and+results.">Endoscopic septoplasty: indications, technique, and results.</a> Otolaryngology-Head and Neck Surgery. 120 (5), 678-682 (1999).</li><li>Fettman, N., Sanford, T., Sindwani, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+management+of+the+deviated+septum:+techniques+in+septoplasty.">Surgical management of the deviated septum: techniques in septoplasty.</a> Otolaryngologic Clinics of North America. 42 (2), 241-252 (2009).</li><li>Killian, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+submucous+window+resection+of+the+nasal+septum.">The submucous window resection of the nasal septum.</a> Annals of Otology, Rhinology &amp; Laryngology. 14, 363-393 (1905).</li><li>Freer, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+correction+of+deflections+of+the+nasal+septum+with+a+minimum+of+traumatism.">The correction of deflections of the nasal septum with a minimum of traumatism.</a> The Journal of The American Medical Association. 38, 636-642 (1902).</li><li>Aaronson, N. L., Vining, E. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correction+of+the+deviated+septum:+from+ancient+Egypt+to+the+endoscopic+era.">Correction of the deviated septum: from ancient Egypt to the endoscopic era.</a> International Forum of Allergy &amp; Rhinology. 4 (11), 931-936 (2014).</li><li>Bloom, J. D., Kaplan, S. E., Bleier, B. S., Goldstein, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Septoplasty+complications:+avoidance+and+management.">Septoplasty complications: avoidance and management.</a> Otolaryngologic Clinics of North America. 42 (3), 463-481 (2009).</li><li>Rettinger, G., Kirsche, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complications+in+septoplasty.">Complications in septoplasty.</a> Facial Plastic Surgery. 22 (4), 289-297 (2006).</li><li>Cottle, M. H., Loring, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Newer+concepts+of+septum+surgery;+present+status.">Newer concepts of septum surgery; present status.</a> Eye, Ear, Nose &amp; Throat Monthly. 27 (9), 403-406 (1948).</li><li>Gibson, T., Davis, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+distortion+of+autogenous+cartilage+grafts:+Its+causes+and+prevention.">The distortion of autogenous cartilage grafts: Its causes and prevention.</a> British Journal of Plastic Surgery. 10, 257-274 (1958).</li><li>Kenedi, R. M., Gibson, T., Abrahams, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanical+characteristics+of+skin+and+cartilage.">Mechanical characteristics of skin and cartilage.</a> Human Factors. 5, 525-529 (1963).</li><li>Stenstroem, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+&amp;#34;natural&amp;#34;+technique+for+correction+of+congenitally+prominent+ears.">A &amp;#34;natural&amp;#34; technique for correction of congenitally prominent ears.</a> Plastic and Reconstructive Surgery. 32, 509-518 (1963).</li><li>Fry, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interlocked+stresses+in+human+nasal+septal+cartilage.">Interlocked stresses in human nasal septal cartilage.</a> British Journal of Plastic Surgery. 19 (3), 276-278 (1966).</li><li>Wang, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modified+septoplasty+with+three+high+tension+lines+resection.">A modified septoplasty with three high tension lines resection.</a> Acta Oto-Laryngologica. 130 (5), 593-599 (2010).</li><li>Trimarchi, M., Bellini, C., Toma, S., Bussi, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Back-and-forth+endoscopic+septoplasty:+analysis+of+the+technique+and+outcomes.">Back-and-forth endoscopic septoplasty: analysis of the technique and outcomes.</a> International Forum of Allergy &amp; Rhinology. 2 (1), 40-44 (2012).</li><li>Kilicaslan, A., Acar, G. O., Tekin, M., Ozdamar, O. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+the+long-term+effects+of+septoplasty+surgery+on+olfactory+function.">Assessment the long-term effects of septoplasty surgery on olfactory function.</a> Acta Oto-Laryngologica. 136 (10), 1079-1084 (2016).</li><li>Meeuwis, J., Verwoerd-Verhoef, H. L., Verwoerd, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+and+abnormal+nasal+growth+after+partial+submucous+resection+of+the+cartilaginous+septum.">Normal and abnormal nasal growth after partial submucous resection of the cartilaginous septum.</a> Acta Oto-Laryngologica. 113 (3), 379-382 (1993).</li><li>Lopatin, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Do+laws+of+biomechanics+work+in+reconstruction+of+the+cartilaginous+nasal+septum.">Do laws of biomechanics work in reconstruction of the cartilaginous nasal septum.</a> European Archives of Oto-Rhino-Laryngology. 253 (4-5), 309-312 (1996).</li><li>D'Ascanio, L., Manzini, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quick+septoplasty:+surgical+technique+and+learning+curve.">Quick septoplasty: surgical technique and learning curve.</a> Aesthetic Plastic Surgery. 33 (6), 814-818 (2009).</li></ol>

The authors have nothing to disclose.

The 2LoRs procedure is based on embryological and anatomic knowledge of deviated nasal septa. The nasal septum consists of three different components: the anterior membrane, cartilage in the middle, and posterior and inferior bone. During the development of the nasal septum, the different components ossify in different time sequences. It is commonly held that the bone finishes its extension while the cartilage still grows. Therefore, stresses accumulate on the margins of the cartilage adjacent to the osseous septum, resulting in the initial forces that may deform the nasal septum. As a consequence, in most cases, the nasal septum deviates to some degree from the midline position14. Therefore, the principle of 2LoRs is to change the anatomy of the nasal septum by releasing the forces at the junction of the cartilage and osseous septum that cause the nasal septal deviation and the ones that impede the shaping and repositioning of the cartilage.
In this septoplasty procedure, two strips of the septal cartilage and its adjacent septal bone were resected to remove the excess cartilage and bone and release the stresses that have accumulated on the two lines. The extent of the removal depended on the significance of the cartilaginous deviation. Generally speaking, the more significant the deviation, the more excess was removed. Based on our clinical observation, in most cases, the vertical dimension of the resected cartilage strip on the second line was from 1/4 to 1/3 of the original height of the septal cartilage and similar to the anteroposterior dimension of the cartilage resection on the first line. For those with the septal cartilage of abnormal thickness and/or lack of elasticity, the dimensions were adjusted to 1/3 to 1/2 of the original height of the cartilage. As reported by Meeuwis et al., the partial resection of the margins of the septal cartilage as large as the extent in 2LoRs has no effect on the postnatal growth of the nasal dorsum17. Therefore, 2LoRs might be performed on children and adolescents with nasal airway obstruction who fail medical treatments and pursue surgical intervention.
The septoplasty technique with 2LoRs presented here had a fairly low rate of complications and satisfied the subjective and objective assessment results. This should be attributed to the following surgical tips. First, care should be taken when the mucosa is elevated, as a full elevation of mucosa helps to release the forces that may impede the shaping and repositioning of the cartilage18. To this end, the Killian incision was started as high as possible and continued to the floor of the nasal cavity. We then fully elevated the unilateral mucoperichondrium on the convex side and the bilateral mucoperiosteum, vertically from the anterior margin of the quadrangular cartilage to the floor of the nasal cavity and horizontally from the mucocutaneous junction to the extent that the bony deformities were fully exposed and visualized. In addition, as suggested in the biomechanical principles applied to septoplasty, the elevation of the mucoperichondrium from the convex side bows the cartilage toward its intact surface, thereby moving back to the midline18. Moreover, the intact mucoperichondrial attachment on the concave side stabilizes the cartilage and potentially provides a blood supply in favor of the healing process19. Second, the interrupted sutures are used to approximate the mucosal flaps and to stabilize the septal cartilage and overlying mucosa; this can prevent postoperative complications, such as septal hematoma, bleeding, and perforation. Third, based on clinical observations, the straight rigid framework helps move the septal cartilage back to the midline via the fixation of the cartilage and mucosa. This is probably because the studied cases excluded the abnormal appearance of the nose (e.g., a crooked nose and caudal dislocation), so the whole surrounding anatomic structure adjacent to the margins of the septal cartilage was on the midline after the correction of the bony septum.
It should be noted that, in rare cases, there were still visible residual deviations within the remaining quadrangular cartilage after 2LoRs in our study. Usually, this is due to the high anterior or superior bends and the severe inherent deviation of the quadrangular cartilage. In this situation, the concave surface of the deviation should be exposed, and multiple scratches might be needed on this side for the adequate repositioning of the quadrangular cartilage to the midline.
Two caveats of this study must be acknowledged. First, it would be more comprehensive if there had been a control group of traditional septoplasties, such as SMR, which has effective results in morphology correction and functional improvement. Therefore, the effect comparison of 2LoRs and traditional septoplasties warrants further investigation, especially by means of a prospective randomized controlled study. Second, a longer follow-up period might be needed to record complications such as saddle nose.
To sum up, 2LoRS provides an effective and safe procedure that can be used to correct the deviated nasal septum in the absence of external nasal deformity to improve nasal patency or to improve access to the middle meatus or to the axillary region of the middle turbinate as a preoperative operation. This procedure helps to minimize the removal of quadrangular cartilage and may expand the indication of septoplasty in children and adolescents.

Endoscopic septoplasty is a commonly performed surgical procedure in otolaryngology to treat nasal airway obstruction caused by nasal septal deviation1. The purpose of the septoplasty with the indication of nasal airway obstruction is to provide a functional improvement in nasal airway patency, and the principle is to correct the septal deviation with a minimal surgical invasion2.
The beginning of septoplasty, a procedure that is still used today, traces back to the technique that Freer and Killian published in the early 20th century, which was called submucous resection (SMR)3. SMR is characterized by its direct removal of a nasal cartilaginous deviation in a subperichondrial plane, leaving an L-shaped strut to structurally support the appearance of the nose4,5. SMR showed advantages over the previous techniques at its time, so it gradually gained acceptance. In the 1990s, endoscopy was applied to septoplasty1. The illumination and visualization of the surgical field were highly improved, and the resection could be performed directly and precisely6. Thereafter, the indications of SMR were extended, and various septoplasty techniques were developed. While these techniques may be diversified in incision, flap elevation, excision, suture, or packing, the essence of direct removal has not changed. Therefore, once the cartilage was significantly resected, complications such as large septal perforations or a saddle nose deformity would occur7,8.
As Cottle and Loring suggested in 1948, the resection of deviated cartilage should be conservative9. Different from the direct removal of cartilaginous deviation, the biomechanics of cartilage as applied to septoplasty require the utilization of the inherent elastic property of cartilage to straighten the cartilaginous deviation by a limited surgical intervention, such as partial incisions (e.g., scratches or thin slices) and full incisions (e.g., full cuts or wedges). In 1958, Gibson and Davis first reported that cartilage has an internal self-locked stress system as a result of its growth pattern10. Partial incisions on the concave side would release the stress, thereby decreasing the bowing of the cartilage, while the incisions on the convex side would increase the bowing. In 1963, Kenedi, Gibson, and Abrahams further demonstrated the self-locked stress system through a series of studies on mapping the force distribution in a cross-section of rib cartilage11. In the same year, Stenstrom verified the effect of partial incisions on the antihelix12. A few years later, Fry published results on the human nasal septal cartilage that were consistent13. In other words, the biomechanics of cartilage can be used to alter the morphology of cartilage by releasing the forces within the cartilage. Based on this theoretical foundation, a surgical procedure that takes advantage of the biomechanical features of cartilage was developed14.
Combining previous surgical procedures with the embryologic and anatomic knowledge of the nasal septum, here, a modified endoscopic septoplasty procedure with the technique of limited two-line resection (2LoRs) at the posterior and inferior junction of the cartilaginous and bony septum (Figure 1) is presented in detail. This procedure is recommended to correct deviated nasal septa when external nasal deformities are absent, to improve nasal patency or to improve access to the middle meatus or to the axillary region of the middle turbinate as a preoperative operation. This procedure may also be used in children to correct septal deviation because of its minimally invasive approach.

<table><tbody><tr><td>Nasal Endoscopy (0&lt;sup&gt;o&lt;/sup&gt;)</td><td>Karl Storz-Endoskope</td><td>7230 AA</td><td></td></tr><tr><td>Tetracaine</td><td>Eye &amp;amp; ENT Hospital of Fudan University</td><td>180130</td><td></td></tr><tr><td>Epinephrine Hydrochloride Injection</td><td>Shanghai Harvest Pharmaceutical Co., Ltd</td><td>10170405</td><td></td></tr><tr><td>Number 15 blade</td><td>Shanghai Pudong Jinhuan Medical Products Co., Ltd</td><td>35T1205</td><td></td></tr><tr><td>Suction Elevator</td><td>Zhejiang Tian Song Medical Products Co., Ltd</td><td>B2117.1</td><td>Width: 4 mm</td></tr><tr><td>Electrocoagulation</td><td>Shanghai Hutong Electronics. Co.,Ltd</td><td>GD350-B5</td><td></td></tr><tr><td>4-0 Brided Absorbable Suture</td><td>Covidien Healthcare</td><td>SL-691</td><td></td></tr><tr><td>Rongeur forcep</td><td>Zhejiang Tian Song Medical Products Co., Ltd</td><td>B2300.3</td><td></td></tr><tr><td>Nasopore</td><td>Nasopore, Stryker, USA</td><td></td><td>Lengh: 8 cm</td></tr><tr><td>Gauze</td><td>Ningbo Shenyuan Medical Material Co., Ltd</td><td></td><td>6 cm x 60 cm</td></tr><tr><td>5mm Elevator</td><td>Zhejiang Tian Song Medical Products Co., Ltd</td><td>B2067</td><td>Width: 5 mm</td></tr><tr><td>2mm Elevator</td><td>Shanghai Medical Instruments (Group) Ltd., Corp. Surgical Instruments Factory</td><td>HBL020</td><td>Width: 2 mm</td></tr></tbody></table>

endoscopic septoplasty with limited two-line resection: minimally invasive surgery for septal deviation

Endoscopic septoplasty is a surgical procedure in otolaryngology that is commonly performed to treat nasal airway obstruction caused by nasal septal deviation. It has a long history with multiple variations. In this article, a modified endoscopic septoplasty procedure using the limited two-line resection (2LoRs) technique at the posterior and inferior junction of the cartilaginous and bony septum is presented based on embryologic and anatomic knowledge of the nasal septum and the biomechanics of cartilaginous behavior. With this procedure, the quadrangular cartilage can be preserved as much as possible, which is helpful in retaining the supporting framework and rigidness of the septum. 2LoRs has been proven effective and sound for the correction of nasal septal deviation with rare complications. This modified procedure can be applied to correct the deviated nasal septum in the absence of any external nasal deformity to improve nasal patency or to improve access to the middle meatus or to the axillary region of the middle turbinate. It may also be used to expand the indications of septoplasty to children and adolescents because of its minimally invasive approach.

Adult patients (&#62;18 years of age) with nasal septal deviation were included in this study. Patients with nasal septal deviation accompanied by chronic rhinosinusitis, sinonasal tumors, external nose deformities, and those with a previous surgical history of septoplasty were excluded. Patients with a straight dorsum but who had caudal cartilage dislocated off the greater alar which had protruded into one of the nasal vestibules were excluded as well.
Thirty-two patients were included in this study. The patients&#39; average age was 44.7 years (with a range of 19 - 72 years) and 68% were male and 32% were female. The VAS score was shown as the mean &#177; the standard deviation. Comparisons between groups were made with a paired Student&#39;s t-test. The VAS decreased from 7.67 &#177; 1.13 before surgery to 1.84 &#177; 1.17 at 6 months after the surgery, which was statistically significant (P &#60;0.01) (Figure 3A). The deviation had returned to the midline of the nasal cavity in most cases, as shown in the representative CT images (Figure 3B).
Only one septum hematoma was recorded as a complication postoperatively. No cases of transient dental pain, hypesthesia, synechiae, epistaxis, septum abscess, septum swing, septal perforation, or saddle nose were recorded in the follow-up visits at 6 months after the surgery.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57678/57678fig1.jpg" /> 
Figure 1: Location of the two-line and the resection area. (A) The first line is located at the junction of the quadrangular cartilage and the perpendicular plate of the ethmoid bone, and the second line is at the junction of the quadrangular cartilage, vomer bone, and maxillary crest. (B) Two incisions were carried out through the quadrangular cartilage. Two strips of septal cartilage and the adjacent bony septum were resected. <a href="https://www.jove.com/files/ftp_upload/57678/57678fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57678/57678fig2.jpg" /> 
Figure 2: Intraoperative endoscopic photographs. (A) After the mucosa was elevated on the convex side, the incisions were made on the septal cartilage anterior to the first line and superior to the second line, and then the contralateral mucoperiosteum was elevated. (B) A strip of the septal cartilage and the adjacent bony septum was resected from the first line. (C) A strip of the septal cartilage and the adjacent bony septum was resected from the second line. (D) Two interrupted sutures were made to reapproximate the flaps. QC = quadrangular cartilage; MPC = mucoperichondrium; NS = nasal septum. <a href="https://www.jove.com/files/ftp_upload/57678/57678fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57678/57678fig3.jpg" /> 
Figure 3: The effect of 2LoRs. A total of 32 patients with the indication of nasal airway obstruction caused by septal deviation were included in this study. None of the patients had a previous history of septoplasty. To eliminate nasal obstruction caused by other diseases, the patients with chronic rhinosinusitis, a nasal tumor, septal perforation, or with external nose deformities were excluded from this study. (A) The mean VAS score decreased from 7.67 &#177; 1.13 to 1.84 &#177; 1.17 (P &#60;0.01). (B) The septum was deviated to the left nasal cavity before surgery (B1, B2) and was returned to the midline of the nasal cavity after surgery (B3, B4). The data are expressed as the mean &#177; the standard deviation. <a href="https://www.jove.com/files/ftp_upload/57678/57678fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

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Endoscopic Septoplasty with Limited Two-line Resection: Minimally Invasive Surgery for Septal Deviation

Endoscopic septoplasty is a time-honored surgical procedure with multiple variations. This paper focuses on a step-by-step surgical approach to perform a modified septoplasty procedure known as limited two-line resection. This surgical technique can be applied to correct a deviated nasal septum in the absence of an external nasal deformity.

Endoscopic septoplasty is a surgical procedure in otolaryngology that is commonly performed to treat nasal airway obstruction caused by nasal septal ...

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16.5K Views.  Fudan University. Endoscopic septoplasty is a time-honored surgical procedure with multiple variations. This paper focuses on a step-by-step surgical approach to perform a modified septoplasty procedure known as limited two-line resection. This surgical technique can be applied to correct a deviated nasal septum in the absence of an external nasal deformity.

Video: Endoscopic Septoplasty with Limited Two-line Resection: Minimally Invasive Surgery for Septal Deviation

Endoscopic Endonasal Trans-sphenoidal Approach: Minimally Invasive Surgery for Pituitary Adenomas

Endoscopic endonasal trans-sphenoidal surgery has become the gold standard for the surgical treatment of pituitary adenomas and many other pituitary lesions. Refinements in surgical techniques, technological advancements, and incorporation of neuronavigation have rendered this surgery minimally invasive. The complication rates of this surgery are very low while excellent results are consistently obtained through this approach.
This paper focuses on the step-by-step surgical approach to pituitary adenomas, which is based on personal experience, and details the results obtained with this minimally invasive surgery.

The aim of this paper is to describe the different steps of the endoscopic endonasal approach to the sella turcica.

Endoscopic endonasal trans-sphenoidal surgery has become the gold standard for the surgical treatment of pituitary adenomas and many other pituitary ...

Neuroscience

Standardized Technique of Aortic Valve Re-implantation for Valve-sparing Aortic Root Replacement

Despite the obvious advantages of the preservation of a normal aortic valve during aortic root replacement, the complexity of valve sparing procedures prevents a number of cardiac surgeons from incorporating them into their practice. The aim of this protocol is to describe a simplified and user-friendly technique of an aortic valve-sparing root replacement (VSRR) procedure by re-implantation of the aortic valve. Proper selection of patients and limitations of the technique are discussed.
In 54 consecutive patients, normal appearing aortic valves were re-implanted in a commercially available polyester prosthesis with pre-shaped sinuses by a simplified and standardized technique. Placement of the first row of the proximal suture line, choice of the prosthesis size, and adjustment of the height of the commissures of the patient to the fixed height of the sinus portion of the prosthesis were slightly modified from the reference techniques with the aim of increasing its feasibility for use by other cardiac surgeons. Early mortality and morbidity as well as 5-year survival, freedom from aortic valve reoperation, and freedom from recurrent moderate regurgitation were collected in all patients.
Thirty-day mortality, re-sternotomy for bleeding, re-sternotomy for mediastinitis, and the incidence of stroke were very low, 1.8% for each (1 of 54). No patient required permanent pace-maker implantation. At 5 years, survival, freedom from aortic valve reoperation, and freedom from recurrent moderate regurgitation were 97.5%, 95.2%, and 91.6%, respectively.
Mid-term results of our standardized technique of re-implantation of the aortic valve for valve-sparing aortic root replacement are very good and compare with more complex techniques reported by experienced surgeons. By following the present protocol of the standardized re-implantation technique, a greater number of cardiac surgeons can perform this procedure with comparable good results.

Valve-sparing aortic root replacement has the advantage of preserving the patient&#39;s own aortic valve. The complexity of the reported techniques to date restricts their use to a limited number of cardiac surgeons. This protocol describes step-by-step a standardized technique reproducible by a greater number of cardiac surgeons.

Despite the obvious advantages of the preservation of a normal aortic valve during aortic root replacement, the complexity of valve sparing procedures ...

Role of Diffusion MRI Tractography in Endoscopic Endonasal Skull Base Surgery

Endoscopic endonasal surgery has gained a prominent role in the management of complex skull base tumors. It allows the resection of a large group of benign and malignant lesions through a natural anatomical extra-cranial pathway, represented by the nasal cavities, avoiding brain retraction and neurovascular manipulation. This is reflected by the patients' prompt clinical recovery and the low risk of permanent neurological sequelae, representing the main caveat of conventional skull base surgery. This surgery must be tailored to each specific case, considering its features and relationship with surrounding neural structures, mostly based on preoperative neuroimaging. Advanced MRI techniques, such as tractography, have been rarely adopted in skull base surgery due to technical issues: lengthy and complicated processes to generate reliable reconstructions for inclusion in the neuronavigation system. 
This paper aims to present the protocol implemented in the institution and highlights the synergistic collaboration and teamwork between neurosurgeons and the neuroimaging team (neurologists, neuroradiologists, neuropsychologists, physicists, and bioengineers) with the final goal of selecting the optimal treatment for each patient, improving the surgical results and pursuing the advancement of personalized medicine in this field.

We present a protocol to integrate diffusion MRI tractography in patient work-up to endoscopic endonasal surgery for a skull base tumor. The methods for adopting these neuroimaging studies in the pre- and intra-operative phases are described.

Endoscopic endonasal surgery has gained a prominent role in the management of complex skull base tumors. It allows the resection of a large group of ...

Combined Endoscopic and Transoral Approach for Total Maxillectomy

The technique of maxillectomy has been revised since it was first described in the 1820s. During the past decade, the endoscopic approach has been widely practiced for resecting maxilla. Compared with the traditional approaches, the combined endoscopic and transoral approach has many advantages such as avoiding facial incisions and postoperative scars and better visualization of the surgical margin. However, this technique is complicated to master and possess several challenges. Here, we demonstrate this approach step-by-step to show how to perform a total maxillectomy. We also reported nine cases with malignant tumors originating from the maxilla, and for all of them total maxillectomy was performed with combined endoscopic and transoral approach. Our data showed that the combination of the endoscopic and transoral approach could be used to resect the total maxilla successfully, though the tumor extended to the infratemporal and pterygopalatine fossa should be treated very carefully to avoid its spread in the local area. Furthermore, besides denture, other reconstruction methods should be attempted to improve the postoperative quality of life after the total maxillectomy.

The technique of maxillectomy has been revised since it was first described in the 1820s. During the past decade, the endoscopic approach has been widely ...

Low-Cost Single-Port (LoCoSP) Device for a Transcervical Approach in Minimally Invasive Transhiatal Esophagectomy

Esophagectomy remains the preferred option to achieve curative treatment in advanced esophageal cancer, but the choice of surgical approach remains controversial. A transthoracic approach may improve lymph node dissection, but it has considerable morbidity and respiratory complications. Transhiatal access has been demonstrated as an efficient means of minimizing post-operative complications. Minimally invasive transhiatal esophagectomy may reduce operative trauma and morbidity as well as enhance postoperative recovery with no compromise in cancer recurrence or survival. Nevertheless, it has a technical limitation in terms of cervical esophagus dissection. Thus, a low-cost single-port device was developed to complete upper mediastinal dissection by a transcervical approach during minimally invasive transhiatal esophagectomy. This device uses a nasogastric tube, a number-eight sterile glove, a sterile sponge, and 3 permanent 5-mm trocars. The step-by-step process of transhiatal esophagectomy and the development of this device are described. This technique allows for the dissection of the upper mediastinum, as well as the esophagus over the aortic arch and behind the superior portion of the trachea. The harvesting of lymph nodes along the left recurrent laryngeal nerve and paratracheals was improved.

Low-Cost Single-Port LoCoSP Device for a Transcervical Approach in Minimally Invasive Transhiatal Esophagectomy

Here, we describe a step-by-step description of transhiatal esophagectomy and the development of a low-cost single-port device for a transcervical approach in a minimally invasive transhiatal esophagectomy.

Esophagectomy remains the preferred option to achieve curative treatment in advanced esophageal cancer, but the choice of surgical approach remains ...

Step-by-Step Stapedotomy through Transcanal Exclusive Endoscopic Approach

In recent years there has been an increasing trend in the use of the endoscope to treat a variety of middle ear pathologies, including otosclerosis. Several studies comparing traditional microscopic and endoscopic stapes surgery have reported similar hearing results and an overall low rate of complications. The endoscope has unraveled its full potential in demanding settings of stapes surgery, such as unfavorable anatomy of the oval window niche or revision cases. Reduced manipulation of the chorda tympani and low rate of post-operative dysgeusia are further benefits to mention for endoscopic stapes surgery.
Being a one-handed technique, management of bleeding, positioning, and crimping of the prosthesis may be challenging for novice endoscopic surgeons, so some training in endoscopic ear surgery is recommended before performing endoscopic stapedotomy. The problem of sharing the surgical field between the endoscope and the operating instruments could be easily overcome if proper instruments positioning is understood. One-handed bleeding control in the narrow space of the ear canal may represent an issue during the elevation of the tympano-meatal flap, possibly discouraging the surgeon since the preliminary steps of surgery. Following appropriate technique to raise the flap and the collaboration with the anesthesiology team in keeping the blood pressure low guarantee an adequate bleeding control in most cases.
The aim of this article is to describe the entire surgical procedure of a transcanal exclusive endoscopic stapedotomy, from operating room set up and patient positioning to post-operative care. A step-by-step description of the surgical maneuvers with technical hints is reported, to guide the surgeon across the procedure and allow any ear surgeon to perform stapes surgery endoscopically.

The aim of this article is to provide a step-by-step method for endoscopic stapes surgery from operating room setting and patient positioning to post-operative care. This work would represent a guide for any otologic surgeon who is willing to treat otosclerosis with endoscopic transcanal technique.

In recent years there has been an increasing trend in the use of the endoscope to treat a variety of middle ear pathologies, including otosclerosis. ...

Endoscopic Cholesteatoma Surgery

Implementation of endoscopes in cholesteatoma surgery resulted in considerable changes in the management of cholesteatoma in the last two decades. Compared to the microscopic approach with an excellent but straight-line view and limited illumination, the introduction of endoscopes provides a wide-angled panoramic view. Moreover, angled lenses allow the surgeon to visualize the middle ear and its hidden recesses through a transcanal, minimally-invasive approach. The endoscope enables the surgeon to remove limited cholesteatoma of the middle ear and its recesses using an exclusive endoscopic technique by taking advantage of these benefits. This reduces the rate of residual disease and sparing external incisions and excessive temporal bone drilling as in a transmastoid approach. Since transcanal endoscopic access is mainly a one-handed technique, it implies the need for specific procedures and technical refinements. This article describes a step-by-step guide as a surgical manual for endoscopic removal of epitympanic cholesteatoma. Different techniques for cholesteatoma dissection and bone removal for epitympanectomy, including curettage and powered instruments such as drills and ultrasonic devices with their outcomes, are discussed. This may offer ear surgeons insight into technical refinements and the latest technological developments and open the horizon for different techniques.

The present protocol describes a step-by-step guide for the complete endoscopic removal of epitympanic cholesteatoma with different techniques for cholesteatoma dissection and bone removal for epitympanectomy.

Implementation of endoscopes in cholesteatoma surgery resulted in considerable changes in the management of cholesteatoma in the last two decades. ...

Full-Endoscopic Decompression for Thoracic Ossification of the Ligamentum Flavum Combined with Dural Ossification

Ossification of the ligamentum flavum (OLF) can result in spinal stenosis. Thoracic spinal cord compression due to spinal stenosis is a common cause of progressive thoracic myelopathy in Asian countries. The incidence of complications is high in open decompression surgeries for thoracic OLF. With dural ossification (DO), the risk of complications is even higher in thoracic OLF. We introduce a full-endoscopic decompression surgery for thoracic OLF combined with DO under local anesthesia. Hemilaminectomy is performed using a high-speed burr under the endoscopy first, and then decompression of the contralateral spinal canal is completed using an "over the top" technique. DO resection uses the eggshell technique; after the base of the DO is cut from the lamina, forceps or lamina rongeurs are typically used for removal. The dural defect left after resection does not need repair. Neurological function was improved, and no complications such as hematoma or neck pain occurred. On imaging, no pseudodural cyst, cerebrospinal fluid leakage, or wound complications were observed after the operation. Endoscopic surgery causes less damage to the posterior ligament complex, so no cases of persistent back pain complaints or secondary internal fixation requirements were found in this study. Full-endoscopic decompression can achieve good imaging and clinical effects in the treatment of thoracic OLF with DO.

We describe a minimally invasive surgery using a full-endoscopy system for the single segmental thoracic ossification of the ligamentum flavum, combined with dural ossification, at Hebei General Hospital.

Ossification of the ligamentum flavum (OLF) can result in spinal stenosis. Thoracic spinal cord compression due to spinal stenosis is a common cause of ...

Full-Endoscopic Interlaminar Approach for Decompression of Lateral Recess Stenosis

For lateral recess stenosis, extensive decompression with laminectomy is still performed in most centers. However, tissue-sparing surgeries are becoming more common. Full-endoscopic spinal surgeries have the advantages of being less invasive and offering a shorter recovery time. Here, we describe the technique of the full-endoscopic interlaminar approach for the decompression of lateral recess stenosis. The full-endoscopic interlaminar approach for the lateral recess stenosis procedure took approximately 51 min (range of 39-66 min). Blood loss could not be measured due to continuous irrigation. However, no drainage was required. There were no dura mater injuries reported in our institution. Furthermore, there were no injuries to the nerves, no cauda equine syndrome, and no hematoma formation. The patients were mobilized on the same day as surgery and discharged the next day. Therefore, the full-endoscopic technique for lateral recess stenosis decompression is a feasible procedure that lowers the operational time, complications, traumatization, and rehabilitation duration.

Technical advances and increased experience in full-endoscopic spinal surgeries enable these procedures to be performed with minimal incision, muscle retraction, and bone removal.

For lateral recess stenosis, extensive decompression with laminectomy is still performed in most centers. However, tissue-sparing surgeries are becoming ...

Clinical Application of Single-Surgeon, Three-Port, Laparoscopic Resection for Colorectal Cancer with Natural Orifice Specimen Extraction

Reduced-port laparoscopic surgery (RPLS) has been widely used for the radical resection of gastrointestinal tumors. Single-surgeon, three-port, laparoscopic radical resection for sigmoid colon or high rectal cancer with natural orifice specimen extraction surgery (NOSES) has the advantage of a small incision, quick postoperative recovery, and short hospital stay. Yet, there are still only a few reports on NOSES. This paper describes the indications, preoperative preparations, surgical steps, and precautions for single-surgeon, three-port, laparoscopic radical resection of the sigmoid colon and high rectal cancer, and intraoperative specimen collection through the natural orifice. 
The protocol focuses on the steps of radical dissection and the main technical points of resection and reconstruction. At the same time, a procedure for fixing an anvil seat by self-traction of extracorporeal silk thread, used for purse-string suture fixation after the proximal anvil was placed in the abdominal cavity, was creatively improved. This operation could effectively avoid problems such as an insufficient proximal intestinal tube, shaking off the anvil seat, and weak purse-string suture during a single operation. The surgical care had less variability and was easy to perform, effectively avoiding postoperative anastomotic leakage and bleeding due to excessive intraoperative anastomotic tissue. This surgery could be widely promoted in primary hospitals.

Here, we present a protocol to successfully perform single-surgeon, three-port, laparoscopic resection for colorectal cancer with natural orifice specimen extraction.