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 border="0" cellpadding="0" cellspacing="0" style="width:755px;" width="755">
	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Nasal Endoscopy (0o)</td>
			<td style="width:221px;">Karl Storz-Endoskope</td>
			<td style="width:127px;">7230 AA</td>
			<td style="width:180px;"></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Tetracaine</td>
			<td style="width:221px;">Eye &#38; ENT Hospital of Fudan University</td>
			<td style="width:127px;">180130</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Epinephrine Hydrochloride Injection</td>
			<td style="width:221px;">Shanghai Harvest Pharmaceutical Co., Ltd</td>
			<td style="width:127px;">10170405</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Number 15 blade</td>
			<td style="width:221px;">Shanghai Pudong Jinhuan Medical Products Co., Ltd</td>
			<td style="width:127px;">35T1205</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Suction Elevator</td>
			<td style="width:221px;">Zhejiang Tian Song Medical Products Co., Ltd</td>
			<td style="width:127px;">B2117.1</td>
			<td>Width: 4 mm</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Electrocoagulation</td>
			<td style="width:221px;">Shanghai Hutong Electronics. Co.,Ltd</td>
			<td style="width:127px;">GD350-B5</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">4-0 Brided Absorbable Suture</td>
			<td style="width:221px;">Covidien Healthcare</td>
			<td style="width:127px;">SL-691</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Rongeur forcep</td>
			<td style="width:221px;">Zhejiang Tian Song Medical Products Co., Ltd</td>
			<td style="width:127px;">B2300.3</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Nasopore</td>
			<td style="width:221px;">Nasopore, Stryker, USA</td>
			<td style="width:127px;"></td>
			<td>Lengh: 8 cm</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">Gauze</td>
			<td style="width:221px;">Ningbo Shenyuan Medical Material Co., Ltd</td>
			<td style="width:127px;"></td>
			<td>6 cm x 60 cm</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">5mm Elevator</td>
			<td style="width:221px;">Zhejiang Tian Song Medical Products Co., Ltd</td>
			<td style="width:127px;">B2067</td>
			<td>Width: 5 mm</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">2mm Elevator</td>
			<td style="width:221px;">Shanghai Medical Instruments (Group) Ltd., Corp. Surgical Instruments Factory</td>
			<td style="width:127px;">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.remotexs.ntu.edu.sg/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.remotexs.ntu.edu.sg/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.remotexs.ntu.edu.sg/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

Murine Ileocolic Bowel Resection with Primary Anastomosis

Intestinal resections are frequently required for treatment of diseases involving the gastrointestinal tract, with Crohn&#8217;s disease and colon cancer being two common examples. Despite the frequency of these procedures, a significant knowledge gap remains in describing the inherent effects of intestinal resection on host physiology and disease pathophysiology. This article provides detailed instructions for an ileocolic resection with primary end-to-end anastomosis in mice, as well as essential aspects of peri-operative care to maximize post-operative success. When followed closely, this procedure yields a 95% long-term survival rate, no failure to thrive, and minimizes post-operative complications of bowel obstruction and anastomotic leak. The technical challenges of performing the procedure in mice are a barrier to its wide spread use in research. The skills described in this article can be acquired without previous surgical experience. Once mastered, the murine ileocolic resection procedure will provide a reproducible tool for studying the effects of intestinal resection in models of human disease.

Ileocolic resection is commonly performed in several human diseases; however, little is known regarding the impact of intestinal resection on surgical illnesses. This article provides instruction on executing the procedure in mice with high success, providing a means to study the effects of ileocolic resection in models of disease.

Intestinal resections are frequently required for treatment of diseases involving the gastrointestinal tract, with Crohn&#8217;s disease and colon cancer ...

Encapsulation Thermogenic Preadipocytes for Transplantation into Adipose Tissue Depots

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular weight metabolites in tissues of the treated host to achieve long-term survival. The semipermeable membrane allows engrafted encapsulated cells to avoid rejection by the immune system. The encapsulation procedure was designed to enable a controlled release of bioactive compounds, such as insulin, other hormones, and cytokines. Here we describe a method for encapsulation of catabolic cells, which consume lipids for heat production and energy dissipation (thermogenesis) in the intra-abdominal adipose tissue of obese mice. Encapsulation of thermogenic catabolic cells may be potentially applicable to the prevention and treatment of obesity and type 2 diabetes. Another potential application of catabolic cells may include detoxification from alcohols or other toxic metabolites and environmental pollutants.

Here, we present a protocol for encapsulation of catabolic cells, which consume lipids for heat production in intra-abdominal adipose tissue and increase energy dissipation in obese mice.

Cell encapsulation was developed to entrap viable cells within semi-permeable membranes. The engrafted encapsulated cells can exchange low molecular ...

An Anatomical Study of Nerves at Risk During Minimally Invasive Hallux Valgus Surgery

The growing popularity of minimally invasive surgical (MIS) procedures makes it necessary that new anatomical references arise, to aid in tridimensional orientation and localization of structures that are not directly visible to the surgeon. This is especially critical for structures at risk like nerves or blood vessels. Optimization of the handling of cadaveric material and the combination of multiple techniques compensate for the limited availability of adequate specimens. The described protocol combines anatomical plane-by-plane dissection and sectional anatomy of fresh-frozen specimens to help localize relevant structures, such as nerves, arteries, veins and to correctly position the portals during MIS procedures. Depiction of these structures in anatomy textbooks can differ from what is encountered in the surgical field; and for this reason, new anatomical studies with a surgical orientation are needed. However, this is a complex, time-consuming technique requiring specific training. The anatomical references described with the so-called 'clock method' provide the surgeon with an easy and reproducible system to locate the path of the nerves at risk in Hallux Valgus MIS procedures. This model can be extrapolated to many other minimally invasive surgical procedures.

Minimally invasive surgical (MIS) procedures rely on anatomical references to localize structures not directly visible to the surgeon. This manuscript describes a combined method of plane-by-plane dissection and sectional anatomy of fresh-frozen specimens to locate the structures at risk during MIS procedures.

The growing popularity of minimally invasive surgical (MIS) procedures makes it necessary that new anatomical references arise, to aid in tridimensional ...

A Minimally Invasive Model to Analyze Endochondral Fracture Healing in Mice Under Standardized Biomechanical Conditions

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an increased use of mouse models in orthopedic research was noted, most probably because mouse models offer a large number of genetically-modified strains and special antibodies for the analysis of molecular mechanisms of fracture healing. To control the biomechanical conditions, well-characterized osteosynthesis techniques are mandatory, also in mice. Here, we report on the design and use of a closed bone healing model to stabilize femur fractures in mice. The intramedullary screw, made of medical-grade stainless steel, provides through fracture compression an axial and rotational stability compared to the mostly used simple intramedullary pins, which show a complete lack of axial and rotational stability. The stability achieved by the intramedullary screw allows the analysis of endochondral healing. A large amount of callus tissue, received after stabilization with the screw, offers ideal conditions to harvest tissue for biochemical and molecular analyses. A further advantage of the use of the screw is the fact that the screw can be inserted into the femur with a minimally invasive technique without inducing damage to the soft tissue. In conclusion, the screw is a unique implant that can ideally be used in closed fracture healing models offering standardized biomechanical conditions.

This protocol describes a minimally invasive osteosynthesis technique using an intramedullary screw for standardized stabilization of femur fractures, which can be used to analyze endochondral bone healing in mice.

Bone healing models are necessary to analyze the complex mechanisms of fracture healing to improve clinical fracture treatment. During the last decade, an ...

Cone Beam Intraoperative Computed Tomography-based Image Guidance for Minimally Invasive Transforaminal Interbody Fusion

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) approaches have been applied to this technique with an associated decrease in estimated blood loss (EBL), length of hospital stay, and infection rates, while preserving outcomes with traditional open surgery. Previous MIS TLIF techniques involve significant fluoroscopy that subjects the patient, surgeon, and operating room staff to non-trivial levels of radiation exposure, particularly for complex multi-level procedures. We present a technique that utilizes an intraoperative computed tomography (CT) scan to aid in placement of pedicle screws, followed by traditional fluoroscopy for confirmation of cage placement. Patients are positioned in the standard fashion and a reference arc is placed in the posterior superior iliac spine (PSIS) followed by intraoperative CT scan. This allows for image-guidance-based placement of pedicle screws through a one-inch skin incision on each side. Unlike traditional MIS-TLIF that requires significant fluoroscopic imaging during this stage, the operation can now be performed without any additional radiation exposure to the patient or operating room staff. After completion of the facetectomy and discectomy, final TLIF cage placement is confirmed with fluoroscopy. This technique has the potential to decrease operative time and minimize total radiation exposure.

The purpose of this article is to provide image-guidance for minimally invasive transforaminal interbody fusion.

Transforaminal lumbar interbody fusion (TLIF) is commonly used for the treatment of spinal stenosis, degenerative disc disease, and spondylolisthesis. ...

Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or excision. Many of these nodules are identified and excised via minimally invasive thoracic surgery; however, subcentimeter and subsolid nodules are frequently difficult to identify intra-operatively. This can be mitigated by the use of electromagnetic transthoracic needle localization. This protocol delineates the step-by-step process of electromagnetic localization from the pre-operative period to the postoperative period and is an adaptation of the electromagnetically guided percutaneous biopsy previously described by Arias et al. Pre-operative steps include obtaining a same day CT followed by the generation of a three-dimensional virtual map of the lung. From this map, the target lesion(s) and an entry site are chosen. In the operating room, the virtual reconstruction of the lung is then calibrated with the patient and the electromagnetic navigation platform. The patient is then sedated, intubated, and placed in the lateral decubitus position. Using a sterile technique and visualization from multiple views, the needle is inserted into the chest wall at the prechosen skin entry site and driven down to the target lesion. Dye is then injected into the lesion and, then, continuously during needle withdrawal, creating a tract for visualization intra-operatively. This method has many potential benefits when compared to the CT-guided localization, including a decreased radiation exposure and decreased time between the dye injection and the surgery. Dye diffusion from the pathway occurs over time, thereby limiting intra-operative nodule identification. By decreasing the time to surgery, there is a decrease in wait time for the patient, and less time for dye diffusion to occur, resulting in an improvement in nodule localization. When compared to electromagnetic bronchoscopy, airway architecture is no longer a limitation as the target nodule is accessed via a transparenchymal approach. Details of this procedure are described in a step-by-step fashion.

Presented here is a protocol for lung nodule localization using dye marking via electromagnetically navigated transthoracic needle access. The technique described here can be accomplished in the peri-operative period to optimize nodule localization and to successful resection when performing minimally invasive thoracic surgery.

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or ...

A Pre-clinical Rat Model for the Study of Ischemia-reperfusion Injury in Reconstructive Microsurgery

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many areas of biomedical research due to its cost-effectiveness and its translation to humans. This protocol describes a method to create a preclinical free skin flap model in rats with ischemia-reperfusion injury. The described 3 cm x 6 cm rat free skin flap model is easily obtained after the placement of several vascular ligatures and the section of the vascular pedicle. Then, 8 h after the ischemic insult and completion of the microsurgical anastomosis, the free skin flap develops the tissue damage. These ischemia-reperfusion injury-related damages can be studied in this model, making it a suitable model for evaluating therapeutic agents to address this pathophysiological process. Furthermore, two main monitoring techniques are described in the protocol for the assessment of this animal model: transit-time ultrasound technology and laser speckle contrast analysis.

Here, we describe a pre-clinical animal model for studying the pathophysiology of ischemia-reperfusion injury in reconstructive microsurgery. This free skin flap model based on the superficial caudal epigastric vessels in the rat may also allow for the evaluation of different therapies and compounds to counteract ischemia-reperfusion injury-related damage.

Ischemia-reperfusion injury is the main cause of flap failure in reconstructive microsurgery. The rat is the preferred preclinical animal model in many ...

Evaluation of Capnography Sampling Line Compatibility and Accuracy when Used with a Portable Capnography Monitor

Capnography is commonly used to monitor patient&#8217;s ventilatory status. While sidestream capnography has been shown to provide a reliable assessment of end-tidal CO2 (ETCO2), its accuracy is commonly validated using commercial kits composed of a capnography monitor and its matching disposable nasal cannula sampling lines. The purpose of this study was to assess the compatibility and accuracy of cross-paired capnography sampling lines with a single portable bedside capnography monitor. A series of 4 bench tests were performed to evaluate the tensile strength, rise time, ETCO2 accuracy as a function of respiratory rate, and ETCO2 accuracy in the presence of supplemental O2. Each bench test was performed using specialized, validated equipment to allow for a full evaluation of sampling line performance. The 4 bench tests successfully differentiated between sampling lines from different commercial sources and suggested that due to increased rise time and decreased ETCO2 accuracy, not all nasal cannula sampling lines provide reliable clinical data when cross-paired with a commercial capnography monitor. Care should be taken to ensure that any cross-pairing of capnography monitors and disposable sampling lines is fully validated for use across respiratory rates and supplemental O2 flow rates commonly encountered in clinical settings.

The goal of this study was to evaluate the accuracy of capnography sampling lines used in conjunction with a portable bedside capnography monitor. Sampling lines from 7 manufacturers were evaluated for tensile strength, rise time, and ETCO2 accuracy as a function of respiratory rate or supplemental oxygen flow rate.

Capnography is commonly used to monitor patient&#8217;s ventilatory status. While sidestream capnography has been shown to provide a reliable assessment ...

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. ...

Clinical Application of Microscope-Assisted Minimally Invasive Anterior Lumbar Interbody Fusion

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for minimally invasive anterior lumbar interbody fusion (Mini-ALIF). This article is a technical description of anterior lumbar spine surgery under a microscope. We retrospectively collected information on patients who underwent microscope-assisted Mini-ALIF surgery at our hospital between July 2020 and August 2022. A repeated-measures ANOVA was used to compare imaging indicators between periods. Forty-two patients were included in the study. The mean volume of intraoperative bleeding was 180 mL, and the mean operative time was 143 min. The mean follow-up time was 18 months. Apart from one case of peritoneal rupture, no other serious complications occurred. The postoperative foramen and disc height were both higher on average than before surgery. The spreader-assisted micro-Mini-ALIF is simple and easy to use. It can provide good intraoperative disc exposure, good discrimination of important structures, adequate spreading of the intervertebral space, and the restoration of the necessary intervertebral height, which is very helpful for less experienced surgeons.

The technique described in this article is well-suited to the Mini-ALIF procedure, allows for excellent exposure and decompression, and facilitates microscope-assisted manipulation.

This study aims to investigate the technical aspects of microscope-assisted anterior decompression fusion and to introduce a spreader system suitable for ...