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405429
OTO XXX10.1177/0194599811405429Long
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Original Research—Laryngology and Neurolaryngology
Otolaryngology–
Head and Neck Surgery
145(2) 270 –275
© American Academy of
Otolaryngology—Head and Neck
Surgery Foundation 2011
Reprints and permission: sagepub.com/journalsPermissions.nav
DOI: 10.1177/0194599811405429 http://otojournal.org
1
2,3
2,3
1,2
4
No sponsorships or competing interests have been disclosed for this article.
Received December 28, 2010; revised February 24, 2011; accepted
March 9, 2011.
Abstract
Objective. To measure the degree to which the Lindholm laryngeal distending forceps improve visualization during direct laryngoscopy in selected pediatric patients.
Study Design. Case series with chart review.
Setting. Pediatric hospital.
Subjects and Methods. Subjects included children undergoing direct laryngoscopy using the Lindholm laryngeal distending forceps. Intraoperative endoscopic photos with and without false cord retraction via the Lindholm laryngeal distending forceps were obtained from the Seattle Children’s Hospital airway endoscopy photo library. Analysis was performed using imaging software. Comparisons of visible vocal cord and glottic opening areas as well as anterior commissure angles with and without the Lindholm laryngeal distending forceps were performed with a paired and unpaired Student t test.
Results. The use of the Lindholm laryngeal distending forceps increased the glottic opening by a mean of 359% (95% confidence interval [CI], 255%-463%) and increased visualized true vocal cord area by 337% (197%-477%). Angle at the anterior commissure increased from a mean of 24.9° to a mean of
71.5°, resulting in a net mean angle increase of 46.6° (95%
CI, 40.2°-52.9°). All measured changes were statistically significant with P values <.01.
Conclusions. When placed at the level of the false vocal folds, Lindholm laryngeal distending forceps will, at least in certain cases, greatly increase the visible area of the superior surface of the vocal folds, the anterior commissure, and, by increasing the glottic opening, the subglottic region. This improved visualization may enhance the surgeon’s ability to diagnose and treat pathologies in these anatomic regions during direct laryngoscopy.
Keywords
Lindholm laryngeal distending forceps, laryngeal retractor, pediatric endoscopy
D irect laryngoscopy is a commonly performed procedure in pediatric otolaryngology and can be used for both diagnostic and therapeutic purposes. Because of the small caliber of the pediatric airway, achieving sufficient visualization and exposure can be a challenge.
1 Inadequate exposure can make it difficult and even hazardous for the surgeon to manipulate the endolarynx. At our institution, we have adopted techniques advocated by Benjamin and Lindholm 2 to safely gain exposure of the pediatric larynx. One critical component of gaining exposure is the use of a spontaneous ventilation anesthetic technique using total intravenous anesthesia sometimes augmented by insufflated volatile anesthetics.
3 This allows the larynx to be examined without an endotracheal or jet ventilation tube, which could potentially clutter the airway and compromise the surgeon’s view and access. A second critical component is the use, when possible, of relatively large-bore vallecular laryngoscopes, such as the Lindholm and Benjamin-Lindholm models, which, unlike most endolaryngeal laryngoscopes, allow full visualization of adjacent structures in the supraglottic, pyriform sinus, and posterior cricoid regions. As successful as these techniques are, visualization of the superior surface of the true vocal folds is often limited by the overhanging false vocal folds. Furthermore,
1 University of Washington School of Medicine, Seattle, Washington, USA
2 Department of Otolaryngology–Head and Neck Surgery, University of
3
Washington School of Medicine, Seattle, Washington, USA
Division of Pediatric Otolaryngology–Head and Neck Surgery, Seattle
4
Children’s Hospital, Seattle, Washington, USA
Seattle Children’s Research Institute, Seattle, Washington, USA
Accepted for future presentation at the meeting of the American Society of
Pediatric Otolaryngology; April 29 to May 1, 2011; Chicago, Illinois.
Corresponding Author:
Jonathan A. Perkins, DO, Division of Pediatric Otolaryngology–Head and
Neck Surgery, Seattle Children’s Hospital, 4800 Sand Point Way NE, MS
W-7729, Seattle, WA 98105, USA
Email: jonathan.perkins@seattlechildrens.org
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Longstreet et al 271
Figure 1. The Lindholm laryngeal distending forceps with close-up views of the distal end. Note the atraumatic retractor tips.
Figure 2. Use of the Lindholm laryngeal distending forceps (LLDF) in a pediatric patient undergoing direct suspension laryngoscopy.
Note that the LLDF use a minimal amount of space in the lumen of the laryngoscope.
the relaxed, partially adducted position of the true vocal folds seen in the anesthetized larynx can limit thorough inspection and surgical manipulation of the anterior commissure and subglottic regions. An unimpeded inspection of these regions is a critical part of any thorough direct laryngoscopy.
4 The Lindholm laryngeal distending forceps (LLDF), when placed at the level of the false vocal folds, will generally allow full and complete visualization of these regions. We have routinely used the LLDF during direct laryngoscopy at our institution for more than a decade without complication and consider their use a vital part of the exam.
The LLDF (8654B; Karl Storz Endoscopy, Tuttlingen,
Germany) are 2-bladed, bayonet-style, ratcheted self-retaining retractors for use in the endolarynx ( Figures 1 and 2 ). Most important, they are typically placed at the level of the false vocal folds, and, when expanded, directly retract the false folds laterally and indirectly retract or distend the true folds ( Figure
3 ). In our experience, the LLDF facilitate comprehensive and atraumatic laryngeal evaluation and facilitate endoscopic intervention when necessary. The goal of this project was to objectively quantify the improved glottic and subglottic exposure during laryngoscopy with the use of the LLDF.
Figure 3. Placement of the Lindholm laryngeal distending forceps at the level of the false cords.
Approval was obtained from the Seattle Children’s Institutional
Review Board (IRB). The Seattle Children’s Hospital (SCH) quality improvement airway endoscopy database 5 was queried for the years 2009 and 2010. Patients were identified if they had undergone endoscopic airway procedures using the
LLDF and had photographic images available both before and after the placement of the LLDF.
Pre- and post-LLDF placement images were reviewed side-by-side. Patients were excluded if the camera angle or position appeared to vary in photos taken before and after placement of the LLDF or if pathology or camera location
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272 Otolaryngology–Head and Neck Surgery 145(2)
Figure 4. (A) Image set meeting inclusion criteria. Camera position is similar. True vocal cords, glottis, anterior commissure, and interarytenoid muscles are well visualized. (Pathology is idiopathic laryngeal stenosis.) (B) Image set failing to meet inclusion criteria.
Camera position varies significantly between pre- and postretractor images, and anterior commissure is not well visualized in the postretractor placement image.
hindered visualization of the vocal cords, interarytenoid muscle, glottic space, or anterior commissure ( Figure 4 ).
All image sets were processed for analysis using Adobe
Photoshop (Adobe Systems, San Jose, California). Image size was adjusted to 8 × 6.404 inches, and resolution was maintained at a constant value of 72 dpi. Image analysis was then performed using Image J (a public-domain Java image- processing program inspired by NIH Image [National Institutes of Health Research Services, Bethesda, Maryland]). Angle at the anterior commissure (ACA) was measured in degrees
( Figure 5A , B ). True vocal cord area ( Figure 5C , D ) was defined by the area encompassed by the lateral aspect of the true vocal cords (TVC), medial aspect of the TVC, anterior commissure, and arytenoid cartilage. Area of the glottic space
( Figure 5E , F ) was defined laterally by the vocal ligament, posteriorly by the interarytenoid muscle, and anteriorly by the anterior commissure. Relative area was determined by counting the number of pixels within each defined boundary.
Because camera placement and anatomic size were not uniform between patients, we were restricted to comparing within-person change in vocal cord and glottic opening space.
For each parameter measured, the percentage difference between pre- and post-LLDF insertion was calculated. Student t tests were used to determine whether any calculated differences exceeded those that could be attributed to chance. Data were analyzed using STATA 11.0 (StataCorp, College Station,
Texas) and Microsoft Excel (Microsoft Corporation,
Redmond, Washington).
Figure 5. (A) Anterior commissure (ACA) without Lindholm laryngeal distending forceps (LLDF) in place (40.7°) (B) ACA with LLDF in place (86.3°). (C) True vocal cord (TVC) area without LLDF in place (37,660 pixels). (D) TVC area with LLDF in place (60,408 pixels). (E) Glottic area without LLDF in place
(36,773 pixels). (F) Glottic area with LLDF in place (59,794 pixels).
We also performed a search of the University of Washington
Department of Otolaryngology–Head and Neck Surgery
Quality Assurance database for complications attributable to or associated with the LLDF.
Records from 892 patients who underwent laryngoscopy for upper aerodigestive tract procedures were reviewed. The majority of these procedures were fiber-optic laryngoscopies and were excluded (n = 765). A total of 127 patients were selected on the basis of endoscopic images that demonstrated the use of the LLDF. Ninety of these patients were excluded because of an absence of images taken without the forceps.
Eight were excluded because the camera angle and size of the images differed with and without the forceps, making meaningful comparisons impossible. Thus, 29 patients met inclusion criteria. This group defined the study cohort ( Figure 6 ).
From this group, we obtained 34 sets of images clearly demonstrating laryngeal structures before and after placement of the LLDF (3 patients contributed multiple sets of images because of repeat examinations).
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Longstreet et al 273
Figure 6. Cohort assembly demonstrating exclusion of patients resulting in final study population. LLDF, Lindholm laryngeal distending forceps; SCH, Seattle Children’s Hospital.
The average age in the study cohort was 7.6 years (range,
11 months to 20 years; median age, 6.5 years). Of the patients,
Table 1. Cohort Demographics and Pathology
Sex, No. (%)
55% were female (n = 16) and 45% were male (n = 13).
Demographic and disease-specific data are summarized in
Table 1 . The most common pathology demonstrated in the cohort was laryngeal stenosis. A significant portion of our
Male
Female
Indication for surgery, No. (%)
Laryngeal stenosis cohort also suffered from recurrent respiratory papillomatosis.
Representative examples with various pathologies are shown in Figure 7 .
There was a more than 3-fold enlargement in the area of the
Papilloma
Hemangioma
Chronic aspiration
Injury/scarring glottic opening (95% confidence interval [CI], 2.55-4.63; range, Vocal polyps
1.21-12.60). Similarly, there was a 3.4-fold increase in the visible Supraglottic cysts area of the superior surface of the vocal folds (95% CI, 1.97-4.77; Granuloma range, 1.32-24.65). The angle at the anterior commissure increased Age from a mean of 24.9° to a mean of 71.5°, resulting in a mean Mean, y increase in angle of 46.6° (95% CI, 40.2°-52.9°). The range of
SD, y angle increase at the anterior commissure was 7.5° to 80° ( Table
2 ). Based on a review of these patients’ charts, surgeons’
Min, mo
Max, y
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13 (45)
16 (55)
15 (52)
5 (17)
2 (7)
2 (7)
2 (7)
1 (3)
1 (3)
1 (3)
7.6
4.7
11
20

274 Otolaryngology–Head and Neck Surgery 145(2)
Figure 7. Representative pathologies as better visualized with Lindholm laryngeal distending forceps. (Please note that these do not represent images used in study calculations.) (A) Recurrent respiratory papillomata with laryngeal scarring. (B) Subglottic cysts. (C)
Involuted subglottic hemangioma. (D) Vocal granulomas.
Table 2. Effect of Retractor Placement in Cord Area, Glottic Space, and Angle at Anterior Commissure
TVC area, pixels
Glottic area, pixels
ACA
Preretractor Mean Postretractor Mean
42,541.5
29,661.6
24.9°
99,823.7
65,391.4
71.5°
Mean Difference
(Post – Pre) Mean % Difference
57,282.1
35,729.9
46.6° a
Abbreviations: ACA, anterior commissure; CI, confidence interval; TVC, true vocal cord.
b
Student t test.
Paired t test.
336.8
358.8
96.0
95% CI
196.7%-476.9%
254.9%-462.9%
40.2
o -52.9
o
P Value
<.01
<.01
<.01
b a a memories, and the University of Washington Department of
Otolaryngology–Head and Neck Surgery Quality Assurance database, none of the patients in our study or institution suffered any complications from the use of the LLDF.
For diagnostic and therapeutic purposes, direct visualization of the vocal cords and related airway structures is frequently necessary in children with airway disorders. However, structures superior to the glottis may obstruct the surgeon’s view during laryngoscopy, and the vocal cords themselves may limit visualization of the subglottic and more distal airway.
6
In this study, we demonstrate objectively how use of the
LLDF during pediatric direct laryngoscopy greatly enhances airway visualization, thereby extending our surgical capabilities during these procedures.
As demonstrated in Figure 7 , the lateral half of the superior surface of the vocal fold frequently lies beneath the undistended false vocal fold. Our first measurement, the increase of the visible area of the superior surface of the true cords, showed that with distension, the entire superior surface of the true cords comes into view, typically extending to at least the arcuate line and often beyond into the ventricular mucosa. We have found this to be exceedingly useful in procedures such as papilloma removal, where papilloma growth typically extends into the laryngeal ventricles ( Figure 7A , left vocal cord).
Our second parameter, vocal cord angle, is clinically significant in that it greatly increases the surgeon’s ability to inspect and manipulate the free edge of the vocal cord as well as the anterior commissure. This is desirable for a variety of pathologies, but we would like to point out the special utility during papilloma surgery when the anterior commissure is involved. By allowing the surgeon to clearly delineate the exact junction of the left and right vocal cords, distension of the commissure greatly facilitates accurate papilloma removal on one side without disturbing the opposite cord, regardless of the technique used. This greatly lessens the chance of web formation.
The increased glottic opening measured in our third parameter has many clinical advantages during direct laryngoscopy. First and foremost, it increases the safety of the procedure by opening the airway. This is especially important because our patients are breathing spontaneously without an endotracheal tube. Although this is difficult to measure objectively, it is our impression that long procedures go much more smoothly and require less interruption due to hypoventilation when we use the LLDF. Second, subglottic pathology becomes dramatically more visible
( Figure 7B ). The improved exposure allows pathologies in
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Longstreet et al 275 this region such as papillomas, cysts, scars, and hemangiomas to be examined and excised with what for us has been unparalleled precision.
LLDF are easily inserted into the pediatric airway during endoscopic procedures, generally sit unobtrusively at the bottom of the surgeon’s field of view, and do not preclude the use of other instrumentation via the laryngoscope ( Figure 3 ). It is absolutely critical to note that these “distending forceps” work most effectively when placed so that they directly retract the false cords: they should not be placed through the glottis, and they should not be in direct contact with the true vocal cords.
Although not directly measured in this study, we would like to point out other advantages of the LLDF. First, they will greatly reduce—if not eliminate—any spontaneous movement of the vocal cords, which is highly desirable when working on a larynx with the child breathing spontaneously. This allows the anesthesiologist to run the anesthetic somewhat “lighter,” improving ventilation. Second, even when placed at the level of the false cords, they can atraumatically open a larynx clamped shut in mild laryngospasm, allowing the passage of a small endotracheal tube in this setting without trauma. Third, they may be useful in other parts of the aerodigestive tract, such as the pyriform fossa for treatment of pyriform sinus tracts.
7
Occasionally, the bayonet portion of the LLDF will obscure the view of the posterior glottis. This can be rectified by inserting the forceps in an inverted fashion and suspending the LLDF from the suspension arm of the laryngoscope.
8
Although the LLDF were designed for use in adults, we found they could be effectively and safely used in virtually any pediatric patient, regardless of patient size, except for very small premature infants. We also feel these results are likely equally applicable in adults if the laryngoscopy is performed with a small jet tube, although we have little experience with this modality.
Owing to the retrospective nature of this study, we recognize the possibility of systematic error or bias in patient selection.
Sample size was reduced because we did not have protocols or even informal practice standards that included routinely obtaining pre- and postdistension photographs when direct laryngoscopy was performed. Surface area measurements are likely only an estimation because no protocol was in place to ensure that camera angle and distance from the larynx were identical when pre- and postdistention pictures were obtained (as the photos were taken for clinical purposes). However, we attempted to mitigate the effects of these inconsistencies by evaluating whether camera angle and distance appeared to match in pre- and postdistension photographs, and we excluded individuals if that was not the case. Also, the data presented here are in accordance with our clinical experience using LLDF, demonstrating that the visible area of the surface of the vocal cords, vocal cord angle, and the glottis opening is approximately tripled.
In conclusion, use of the LLDF during direct laryngoscopy provides a significantly improved view of the larynx distal to the false cords, including the vocal cords, anterior commissure, and subglottis. In more than 10 years of routine use, we have had no complications attributable to
LLDF. We feel use of this instrument should be a routine consideration in pediatric direct laryngoscopy along with other pediatric laryngoscopy standards outlined by
Benjamin and Lindholm, 2 such as spontaneous ventilation anesthesia, suspension laryngoscopy via vallecular laryngoscopes, and visual examination by the naked eye, rigid telescope, and binocular microscope.
Acknowledgments
Eden Palmer, figure preparation; Stacy Russ, manuscript preparation.
Author Contributions
Beck Longstreet , study conception and design, analysis and interpretation of data, drafting the article, critical revision of manuscript;
Prabhat K. Bhama , study conception and design, drafting the article, critical revision of manuscript; Andrew F. Inglis Jr , study conception and design, acquisition of data, analysis and interpretation of data, critical revision of manuscript; Babette Saltzman , analysis and interpretation of data, critical revision of manuscript;
Jonathan A. Perkins , study conception and design, acquisition of data, analysis and interpretation of data, critical revision of manuscript.
Disclosures
Competing interests: None.
Sponsorships: None.
Funding source: None.
References
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3. Collins CE. Anesthesia for pediatric airway surgery: recommendations and review from a pediatric referral center. Anesthesiol
Clin . 2010;28:505-517.
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5. Perkins JA, Coltrera MD. Relational databases for rare disease study: application to vascular anomalies. Arch Otolaryngol Head
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6. Perkins JA, Duke W, Chen E, Manning S. Emerging concepts in airway infantile hemangioma assessment and management. Otolaryngol Head Neck Surg . 2009;141:207-212.
7. Chen EY, Inglis AF, Ou H, et al. Endoscopic electrocauterization of pyriform fossa sinus tracts as definitive treatment. Int J Pediatr Otorhinolaryngol . 2009;73:1151-1156.
8. Inglis AF Jr, Perkins JA, Manning SC, Mouzakes J. Endoscopic posterior cricoid split and rib grafting in 10 children. Laryngoscope . 2003;113:2004-2009.
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