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Arytenoid dislocation: Techniques of surgical reduction
ARYTENOID DISLOCATION: TECHNIQUES OF SURGICAL REDUCTION ROBERT THAYER SATALOFF, MD, DMA
Arytenoid dislocation is commonly misdiagnosed as vocal fold paralysis. Accurate, early diagnosis increases the likelihood of easy surgical reduction and good functional outcome. However, successful reduction can be accomplished even many years after arytenoid dislocation. Anterior, posterior, and complex dislocation can occur. Different surgical techniques are appropriate for each arytenoid malposition.
Vocal fold immobility may occur after internal or external neck trauma. The immobility may be caused by vocal fold paresis or paralysis, cricoarytenoid joint fixation, or arytenoid dislocation. Arytenoid dislocation is commonly misdiagnosed as vocal fold paralysis. When accurate diagnosis is delayed, surgical repair becomes more difficult, although not impossible as previously thought. 1,2 Many laryngologists were taught that arytenoid reduction was impossible or inappropriate beyond the first or second week. Our experience suggests that reasonably good results are common so long as the arytenoid is reduced within 10 weeks. 2 Although reduction can be performed even many years after arytenoid dislocation, late reductions usually result in correction of the vertical height disparity without restoration of joint motion.
EMBRYOLOGY AND ANATOMY Understanding the complicated embryology and anatomy of the arytenoid cartilages is helpful in clarifying surgical principles and avoiding complications. The primordium of the larynx, trachea, bronchi, and lungs arises as an outgrowth of the pharynx during the third week of embryonic life, forming a laryngotracheal groove. 3 This anterior groove lies immediately posterior to the hypobranchial eminence and becomes the primitive laryngeal aditus. The aditus lies between the sixth branchial arches. The laryngotracheal groove fuses in a caudocranial direction at about the fourth week. The ventral ends of the sixth branchial arches grow and form the arytenoid eminences. During the seventh week, a fissure appears on each arytenoid eminence extending into the primitive vestibule. This is the laryngeal ventricle. The last portion of the laryngotracheal groove to From the Department of Otolaryngology-Head and Neck Surgery, Thomas Jefferson University, and the Department of OtolaryngologyHead and Neck Surgery,The Graduate Hospital, Philadelphia,PA. Modified in part with permission from Sataloff RT: Professional Voice: The Science and Art of Clinical Care (ed 2). San Diego, CA, Singular Publishing Group, 1997, pp 535-537 and 639-640. Address reprint requests to Robert Thayer Sataloff, MD, DMA, 1721 Pine St, Philadelphia,PA 19103. Copyright © 1998 by W.B. Saunders Company 1043-1810/98/0904-0003510.00/0 196
be obliterated is the intra-arytenoid sulcus at about 11 weeks. Laryngeal hyaline cartilages develop from branchial arch mesoderm, and elastic cartilages are derived from mesoderm of the floor of the pharynx. 4 Most of the arytenoid is composed of hyaline cartilage. However, the vocal processes are developed separately in association with the vocal folds and consist of elastic cartilage. "Arytenoid" comes from the Greek work arytainoeides, meaning ladle-shaped. The cartilages are pyramidal, consisting of an apex, base, and two processes. The base articulates with the cricoid cartilage. The apex attaches to the corniculate cartilage of Santorini and to the aryepiglottic fold. The vocal process projects anteriorly to connect with the vocal ligament, and the muscular process is the point of insertion for most of the muscles that move the arytenoid, s The cricoarytenoid facets are well defined, smooth, and symmetrical. Each arytenoid articulates with an elliptical facet on the posterior superior margin of the cricoid ring. The cricoid facet is about 6 m m long and is cylindrical. 6 Traditional teaching holds that the cricoarytenoid joint motion includes rotating, gliding, and rocking. Most of the cricoarytenoid motion is rocking. However, along the long axis of the cricoid facet, gliding also occurs. 7 Limited rotary pivoting is permitted as well. More recent studies suggest that these traditional descriptions are not fully accurate and that complex revolution may more succinctly describe arytenoid behavior. 8 The arytenoid cartilages and the cricoarytenoid facets are extremely symmetric and consistent. 6 The cricoarytenoid joint is an arthrodial join, supported by a capsule lined with synovium. The capsule is strengthened posteriorly by the cricoarytenoid ligament. 9 This ligament is strong and ordinarily prevents anterior subluxation. The axis of the joint is at an angle of about 45 ° from the sagittal plane and 40 ° from the horizontal plane. The cricoarytenoid joint controls abduction and adduction of the true vocal folds, thereby facilitating respiration, protection of the airway, and phonation. Arytenoid motion is controlled directly by intrinsic laryngeal muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, interarytenoid, and thyroarytenoid. It is also affected by the cricothyroid muscle, which increases longitudinal tension of the vocal fold (which attaches to the vocal process of the arytenoid), and to a
OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEADAND NECK SURGERY, VOL 9, NO 4 (DEC), 1998: PP 196-202
FIGURE 1. Typical appearance of a posterior arytenoid dislocation. The dislocated left arytenoid lifts the vocal process (arrow) so the abnormal side overlaps the mobile vocal fold. (Reprinted with permission from Sataloff RT: Professional Voice: Science and Art of Clinical Care (ed 2). Singular Publishing Group, San Diego, CA, 1997, p 536.)
lesser degree by the thyroepiglottic muscle, which tenses the aryepiglottic fold. ARYTENOID
DISLOCATION:
DIAGNOSIS
Traditionally, arytenoid dislocation has been suspected on the basis of history and absence of the jostle phenomenon present in many cases of unilateral vocal fold paralysis. 1°
Often it is not diagnosed until direct laryngoscopy shows impaired passive mobility of the vocal fold. Preoperative differentiation between vocal fold paralysis and arytenoid dislocation should be possible in virtually all cases. However, if not considered specifically, it will often be missed. Disparity in height between the vocal fold processes is much easier to see in slow motion under stroboscopic light at various pitches than with continuous light. In posterior dislocations, the vocal process and vocal fold are usually higher on the dislocated side (Fig 1). In anterior dislocations, they are generally lower on the abnormal side (Fig 2). In either case, the injured vocal fold may move sluggishly or be immobile. Rarel3~ abduction and adduction may appear almost normal under continuous light. Video documentation of the preoperative and postoperative appearance can prove particularly helpful in cases of arytenoid dislocation not only diagnostically, but also because many of these patients are involved in litigation related to their injuries. The most valuable tests are the stroboscopic examination to visualize differences in vocal process height; computed tomography (CT) scan of the larynx, which should image the arytenoid dislocation and reveal clouding or obliteration of the cricoarytenoid joint space; and laryngeal electromyography to differentiate an immobile dislocated arytenoid joint from vocal fold paralysis. Airflow analysis is also helpful in documenting changes before and after therapy. Strobovideolaryngoscopy is also important to assess other vocal fold injuries. Stiffness and scar of the musculomembranous portion of the vocal folds are found commonly in association with arytenoid dislocation. The trauma causing dislocation frequently involves considerable force that results in vocal fold hemorrhage. It is important to recog-
FIGURE 2. Typical appearance of a severe anterior dislocation. The left arytenoid is tilted forward, and the vocal process pulls the vocal fold to a lower level (arrow), so the mobile right vocal fold overlaps the abnormal side during adduction. (Reprinted with permission from Sataloff RT: Professional Voice: Science and Art of Clinical Care (ed 2). Singular Publishing Group, San Diego, CA, 1997, p 536.) ROBERT THAYER SATALOFF
197
nize the presence of vocal fold scar before reducing an arytenoid dislocation to inform the patient about reasonable expectations for surgical outcome. When the author reported his series of 26 cases in 1994, only 31 additional cases had been reported in the literature. 2 Since that time, additional cases have been documented. 11-2°Although anterior and posterior dislocations are described most commonly, it has been noted previously that the arytenoid can be dislocated in any direction. 2 Complex dislocations have been observed in some of the more than 24 patients cared for by the author since his last report. Posterior dislocation is commonly an extubation injury. The arytenoid is displaced posterolaterally, and the vocal process is high and laterally positioned. Anterior dislocation is most commonly caused by intubation. The laryngoscope engages the posterior lip of the arytenoid, tearing the posterior cricoarytenoid ligament and tipping the arytenoid anteromedially (Fig 3). The vocal process ordinarily is lower than normal in such cases. Complex arytenoid dislocations can be particularly challenging. In our more recent (unreported) cases, direct anterior dislocation has been seen in two patients. In these cases, the arytenoid is anteriorly displaced, but the vocal process is high. This injury requires considerable trauma, with disruption of cartilage. Both cases have followed intubation. With injury of this severity, endoscopic reduction has been less satisfactory than with more typical anterior or posterior dislocations.
TECHNIQUES FOR SURGICAL OF ARYTENOID DISLOCATION
REDUCTION
Although early spontaneous reduction of arytenoid dislocation has been reported, 2 surgical reduction is generally required. Voice therapy for at least a brief period may be helpful in some cases, and preoperative evaluation by a speech-language pathologist is generally recommended. Surgeons should also be aware that nonsurgical approaches have been suggested. For example, Rontal and Rontal, 21 have recently introduced the concept of chemical tenotomy using botulinum toxin to enhance spontaneous reductions. In some cases, adjunct procedures performed at the time of arytenoid reduction may also be advisable, as discussed below.
FIGURE 4. Straight Miller-3 laryngoscope blade used by anesthesiologists. The curved tip with a slight lip (arrow) has proven ideal for the reduction of posterior arytenoid dislocation. (Reprinted with permission from Sataloff RT: Professional Voice: Science and Art of Clinical Care (ed 2). Singular Publishing Group, San Diego, CA, 1997, p 639.) Closed Reduction for Posterior Arytenoid Dislocation
The author has found the anesthesiologist's old-fashioned, straight, Miller-3 laryngoscope blade to be the most useful instrument for posterior arytenoid dislocation (Fig 4). The instrument is placed in the piriform sinus with the rolled tip of the laryngoscope against the infralateral edge of the dislocated cartilage (Fig 5). The surgeon's other hand is placed on the opposite side of the larynx externally to apply counterpressure. The arytenoid is distracted cranially, then manipulated anteromedially to pop the arytenoid back into position. Substantial force is often necessary. A Holinger laryngoscope is usually used to reduce anterior dislocations. More delicate instruments such as cupped forceps are not strong enough and are more likely to lacerate the mucosa and expose cartilage to the risk of infection. No instrument should be placed under the vocal process because of the risk of fracture at the embryologic
FIGURE 3. On the left, a normal larynx can be visualized from the back. The cricoarytenoid ligament is seen on both sides. The interarytenoid muscle has been removed. The posterior cricoarytenoid muscle is preserved on the right. In posterior arytenoid dislocation (center image), the posterior cricoarytenoid ligament is generally made more lax, and it is not torn. In an anterior dislocation (right image), the posterior cricoarytenoid ligament is generally torn (as illustrated) or avulsed from its insertion into the cricoid or arytenoid cartilage. 198
ARYTENOID DISLOCATION
FIGURE 5. To reduce a posterior arytenoid dislocation, the tip of a Miller-3 blade is placed in the piriform sinus (upper left). To reduce a left posterior dislocation, the laryngoscope is rotated medially (lower left) so that the lip on the laryngoscope engages the dislocated arytenoid as the laryngoscope is drawn superiorly out of the piriform sinus. Digital external counterpressure (upper left) is required, and the right hand ordinarily needs to be placed more anteriorly than illustrated in this figure. If illustrated in proper position, the hand would block visualization of the tip of the laryngoscope. Once the arytenoid has been hooked by the lip of the laryngoscope (center), considerable force is necessary to distract the arytenoid in a cephalad direction, and then to rotate it anteromedially, reducing it (right).
FIGURE 6. TO reduce an anterior dislocation, a Holinger laryngoscope is positioned (upper left). To reduce a right arytenoid dislocation, the laryngoscope is rotated about 130 ° (lower left) so that the upper surface of the laryngoscope makes broad contact with the medial surface of the dislocated arytenoid (center). The surgeon's contralateral hand is placed externally, posteriorly on the larynx (upper left) so that the arytenoid is manipulated between the laryngoscope tip and the fingers of the surgeon's right hand to reduce this right arytenoid anterior dislocation. Considerable force is required to reduce the arytenoid (right), and care must be taken not to injure or avulse the vocal process. ROBERT THAYER SATALOFF
1 99
FIGURE 7. Digital reduction can be accomplished occasionally, especially for patients who are edentulous and who have had recent posterior dislocation or redislocation after recent arytenoid reduction. The patient's tongue is retracted by the patient or an assistant, leaving the surgeon's other hand free for external counterpressure. The surgeon's index or middle finger is placed in the piriform sinus, engaging the dislocated arytenoid (center). The surgeon's other hand applies external counterpressure, and the arytenoid is reduced digitally (right).
fusion plane between the vocal process and body of the arytenoid. The Holinger laryngoscope is rotated so that its supralateral surface makes broad contact with the anteromedial face of the arytenoid. The surgeon's other hand is placed against the larynx externally and posteriorly for manipulation and counterpressure (Fig 6). For complex dislocations, a combination of these techniques is used. It may be necessary to refracture the cartilage a n d / o r separate the joint to manipulate the arytenoid. For example, in lateral and anterolateral dislocations, it has been helpful to use the Holinger laryngoscope to disrupt the cartilage and fibrosis, bringing the arytenoid posteriorly. Then, a combination of the Holinger laryngoscope and Miller-3 laryngoscope is used to return the arytenoid to optimal position. When endoscopic closed reduction is not successful or is so unstable that dislocation recurs, open reduction and fixation should be considered. The procedure is performed using a standard arytenoid adduction rotation approach. The joint is entered. If the joint has been obliterated, a "joint" is created sharply. The arytenoid is moved to optimize vocal process position. The surgery is performed with the patient awake, and it is important to adjust vocal rocess position while the patient is phonating at his/her abitual frequency, rather than using a high-pitch / i/. Special situations and challenging clinical conditions sometimes demand other solutions to the problems of arytenoid dislocation. On three occasions, the author has used digital reduction (Fig 7). The first was on an edentulous patient in an intensive care unit who had extubated herself repeatedly. Her physicians were concerned about
~
200
even the risk of transporting her to the operating room, let alone sedating her. Yet she had respiratory problems, and it was important to restore the efficiency of her cough. Her tongue was held with gauze in the manner of indirect laryngoscop:~ at the bedside. An assistant helped stabilize her larynx externally. A finger was placed in her pyriform sinus, and her posterior arytenoid dislocation was manually reduced. It maintained good position, and mobility returned. This technique has been used on two other patients whose arytenoids redislocated within 48 hours of surgical reduction. Most recently, another new technique was used. The author was called to see a patient who had awakened with a hoarse, weak, breathy voice and ineffective cough after anterior cervical fusion. Posterior arytenoid dislocation was diagnosed easily, and good vocal fold innervation was confirmed by electromyography. However, the patient had a short, thick neck and was flexed in a halo device, and on full-dose warfarin. In the operating room, the arytenoid was reduced indirectly under nasal fiberoptic laryngoscopic control. A right-angle bayonet forceps was used. This is the instrument that used to be used routinely for holding cocainized cotton in the pyriform sinuses to provide local anesthesia to the larynx. The tip of the forceps was covered with a red rubber catheter. The instrument was placed in the pyriform sinus, and the arytenoid was lifted cranially, anteriorly, and medially; and it popped back into position easily (Fig 8). It is worthwhile attempting endoscopic reduction even long after the injury. 1,2 In 1998 (not yet reported in detail),
ARYTENOID DISLOCATION
.<
FIGURE 8. This previously undescribed procedure can be used for patients with posterior arytenoid dislocation and difficult anatomical constraints, such as this patient in a halo device. A flexible laryngoscope is placed in the nostril to observe the larynx. A right-angle instrument such as a laryngeal bayonet forceps is covered with a shortened red rubber catheter. The hole in the red rubber catheter (lower left) assists in making stable contact with the dislocated arytenoid. The posterior aspect of the dislocated arytenoid is engaged (center), and drawn superiorly and anteromedially to reduce the dislocated cartilage (right).
the author successfully reduced an anterior arytenoid dislocation that had occurred 38 years previously; restoring vertical s y m m e t r y of the vocal process and fold, although thyroplasty was necessary to p r o v i d e adequate medialization.
ADJUNCTIVE MEASURES Several adjunctive m e a s u r e s should be considered w h e n p e r f o r m i n g arytenoid reduction. For a long-standing posterior dislocation, especially w h e n the reduction seems unstable, s i m u l t a n e o u s medialization should be considered. T h y r o p l a s t y or injection of a u t o l o g o u s fat or collagen not only helps medialize the vocal fold, but also tends to pull the vocal process forward. This helps m a i n t a i n the desired arytenoid position. After anterior dislocation, Rontal a n d Rontal h a v e suggested b o t u l i n u m toxin injection into a d d u c t o r muscles that tend to pull the arytenoid forward. 21 In fact, they h a v e suggested that b o t u l i n u m toxin alone m a y result in spontaneous reduction w i t h o u t the need for surgical intervention. In this a u t h o r ' s opinion, although this m a y be true in s o m e cases, it is not likely to occur once the joint has b e e n fibrosed. More investigation of this novel concept is certainly warranted.
CONCLUSION A r y t e n o i d dislocation is not rare, a l t h o u g h it is often diagnosed incorrectly. A l t h o u g h the goal of treatment is restoration of n o r m a l position and function, this cannot always be achieved. However, e v e n correcting the vertical height a b n o r m a l i t y is worthwhile. Essentially, this simpli-
ROBERT THAYER SATALOFF
ties the problem, converting it to one that can be m a n a g e d easily b y standard medialization surgery. It is essential for the surgeon to u n d e r s t a n d the a n a t o m y and surgical principles involved, because visualization d u r i n g these p r o c e d u r e s is extremely limited, and considerable force is required. In virtually all cases, the patient's voice can be i m p r o v e d , and a i r w a y p r o b l e m s and other significant complications h a v e not b e e n e n c o u n t e r e d thus far.
REFERENCES 1. Sataloff RT, Feldman M, Darby KS, et al: Arytenoid dislocation. J Voice 1:368-377, 1987 2. Sataloff RT, Bough ID, Spiegel JR: Arytenoid dislocation: Diagnosis and treatment. Laryngoscope 104:1353-1361, 1994 3. Lee GJ: Essential Otolaryngology (ed 3). New York, NY, Medical Examination Publishing, 1983, pp 306-310 4. Langman J: Medical Embryology (ed 3). Baltimore, MD, Williams and Wilkins, 1975, pp 269, 272 5. Hollinshead WH: Anatomy for Surgeons, Vol i (ed 3). New York, NY, Harper and Row, 1982, pp 423-427 6. Maue W, Dickson DR: Cartilages and ligaments of the adult human larynx. Arch Otolaryngo194:432-439, 1971 7. von Leden H, Moore P: The mechanics of the cricoarytenoid joint. Arch Otolaryngol 73:63-72, 1961 8. Letson JA Jr, Tatchell R: Arytenoid joint, in Sataloff RT (ed): Professional Voice: Science and Art of Clinical Care (ed 2). San Diego, CA, Singular Publishing Group, 1997, pp 131-146 9. Pennington CL: External trauma of the larynx and trachea. Ann Otol Rhinol Laryngo181:546-554, 1972 10. Sataloff RT, Spiegel JR, Heuer RJ, et al: Pediatric anterior arytenoid dislocation. Ear Nose Throat J 74:454, 1995 11. Sataloff RT, McCarter AA, Hawkshaw M: Posterior arytenoid dislocation. Ear Nose Throat J 77:12, 1998
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12. Szigeti CL, Baeuerle JJ, Mongan PD: Arytenoid dislocation with lighted stylet intubation: case report and retrospective review. Anesth Analg 78:185-186, 1994 13. Alexander AE Jr, Lyons GD, Fazekas-May MA, et al: Utility of helical computed tomography in the study of arytenoid dislocation and arytenoid subluxation. Ann Otol Rhinol Laryngo1160:1020-1023, 1997 14. Gauss A, Treiber HS, Haehnel J, et ah Spontaneous reposition of a dislocated arytenoid cartilage. Br J Anaesth 70:591-592, 1993 15. Hsu CS, Huang CT, So EC, et al: Arytenoid subluxation following endotracheal intubation--a case report. Acta Anaesthesiol Sin 33:4552, 1995 16. Hass I, Gross M: Intubation trauma of the larynx--a literature review
202
17. 18. 19. 20. 21.
with special reference to arytenoid cartilage dislocation. Anasthesiol Intensivmed Notfallmed Schmerzther 31:279-280, 1996 Friedberg J, Giberson W: Failed tracheotomy decannulation in children. J Otolaryngo121:404-408,1992 Talmi YP, Wolf M, Bar-Ziv J, et al: Postintubation arytenoid subluxation. Ann Otol Rhinol Laryngo1105:384-390, 1996 Stack BC Jr, Ridley MB: Arytenoid subluxation from blunt laryngeal trauma. Am J Otolaryngo115:68-73,1994 Hiong YT, Fung CF, Sudhaman DA: Arytenoid subluxation: implications for the anaesthetist. Anaesth Intens Care 24:609-610, 1996 Rontal E, Rontal M: Laryngeal rebalancing in the treatment of anteromedial dislocation of the arytenoids. J Voice 12:383-388,1998
ARY'I'ENOID DISLOCATION
Arytenoid dislocation is commonly misdiagnosed as vocal fold paralysis. Accurate, early diagnosis increases the likelihood of easy surgical reduction and good functional outcome. However, successful reduction can be accomplished even many years after arytenoid dislocation. Anterior, posterior, and complex dislocation can occur. Different surgical techniques are appropriate for each arytenoid malposition.
Vocal fold immobility may occur after internal or external neck trauma. The immobility may be caused by vocal fold paresis or paralysis, cricoarytenoid joint fixation, or arytenoid dislocation. Arytenoid dislocation is commonly misdiagnosed as vocal fold paralysis. When accurate diagnosis is delayed, surgical repair becomes more difficult, although not impossible as previously thought. 1,2 Many laryngologists were taught that arytenoid reduction was impossible or inappropriate beyond the first or second week. Our experience suggests that reasonably good results are common so long as the arytenoid is reduced within 10 weeks. 2 Although reduction can be performed even many years after arytenoid dislocation, late reductions usually result in correction of the vertical height disparity without restoration of joint motion.
EMBRYOLOGY AND ANATOMY Understanding the complicated embryology and anatomy of the arytenoid cartilages is helpful in clarifying surgical principles and avoiding complications. The primordium of the larynx, trachea, bronchi, and lungs arises as an outgrowth of the pharynx during the third week of embryonic life, forming a laryngotracheal groove. 3 This anterior groove lies immediately posterior to the hypobranchial eminence and becomes the primitive laryngeal aditus. The aditus lies between the sixth branchial arches. The laryngotracheal groove fuses in a caudocranial direction at about the fourth week. The ventral ends of the sixth branchial arches grow and form the arytenoid eminences. During the seventh week, a fissure appears on each arytenoid eminence extending into the primitive vestibule. This is the laryngeal ventricle. The last portion of the laryngotracheal groove to From the Department of Otolaryngology-Head and Neck Surgery, Thomas Jefferson University, and the Department of OtolaryngologyHead and Neck Surgery,The Graduate Hospital, Philadelphia,PA. Modified in part with permission from Sataloff RT: Professional Voice: The Science and Art of Clinical Care (ed 2). San Diego, CA, Singular Publishing Group, 1997, pp 535-537 and 639-640. Address reprint requests to Robert Thayer Sataloff, MD, DMA, 1721 Pine St, Philadelphia,PA 19103. Copyright © 1998 by W.B. Saunders Company 1043-1810/98/0904-0003510.00/0 196
be obliterated is the intra-arytenoid sulcus at about 11 weeks. Laryngeal hyaline cartilages develop from branchial arch mesoderm, and elastic cartilages are derived from mesoderm of the floor of the pharynx. 4 Most of the arytenoid is composed of hyaline cartilage. However, the vocal processes are developed separately in association with the vocal folds and consist of elastic cartilage. "Arytenoid" comes from the Greek work arytainoeides, meaning ladle-shaped. The cartilages are pyramidal, consisting of an apex, base, and two processes. The base articulates with the cricoid cartilage. The apex attaches to the corniculate cartilage of Santorini and to the aryepiglottic fold. The vocal process projects anteriorly to connect with the vocal ligament, and the muscular process is the point of insertion for most of the muscles that move the arytenoid, s The cricoarytenoid facets are well defined, smooth, and symmetrical. Each arytenoid articulates with an elliptical facet on the posterior superior margin of the cricoid ring. The cricoid facet is about 6 m m long and is cylindrical. 6 Traditional teaching holds that the cricoarytenoid joint motion includes rotating, gliding, and rocking. Most of the cricoarytenoid motion is rocking. However, along the long axis of the cricoid facet, gliding also occurs. 7 Limited rotary pivoting is permitted as well. More recent studies suggest that these traditional descriptions are not fully accurate and that complex revolution may more succinctly describe arytenoid behavior. 8 The arytenoid cartilages and the cricoarytenoid facets are extremely symmetric and consistent. 6 The cricoarytenoid joint is an arthrodial join, supported by a capsule lined with synovium. The capsule is strengthened posteriorly by the cricoarytenoid ligament. 9 This ligament is strong and ordinarily prevents anterior subluxation. The axis of the joint is at an angle of about 45 ° from the sagittal plane and 40 ° from the horizontal plane. The cricoarytenoid joint controls abduction and adduction of the true vocal folds, thereby facilitating respiration, protection of the airway, and phonation. Arytenoid motion is controlled directly by intrinsic laryngeal muscles, including the posterior cricoarytenoid, lateral cricoarytenoid, interarytenoid, and thyroarytenoid. It is also affected by the cricothyroid muscle, which increases longitudinal tension of the vocal fold (which attaches to the vocal process of the arytenoid), and to a
OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEADAND NECK SURGERY, VOL 9, NO 4 (DEC), 1998: PP 196-202
FIGURE 1. Typical appearance of a posterior arytenoid dislocation. The dislocated left arytenoid lifts the vocal process (arrow) so the abnormal side overlaps the mobile vocal fold. (Reprinted with permission from Sataloff RT: Professional Voice: Science and Art of Clinical Care (ed 2). Singular Publishing Group, San Diego, CA, 1997, p 536.)
lesser degree by the thyroepiglottic muscle, which tenses the aryepiglottic fold. ARYTENOID
DISLOCATION:
DIAGNOSIS
Traditionally, arytenoid dislocation has been suspected on the basis of history and absence of the jostle phenomenon present in many cases of unilateral vocal fold paralysis. 1°
Often it is not diagnosed until direct laryngoscopy shows impaired passive mobility of the vocal fold. Preoperative differentiation between vocal fold paralysis and arytenoid dislocation should be possible in virtually all cases. However, if not considered specifically, it will often be missed. Disparity in height between the vocal fold processes is much easier to see in slow motion under stroboscopic light at various pitches than with continuous light. In posterior dislocations, the vocal process and vocal fold are usually higher on the dislocated side (Fig 1). In anterior dislocations, they are generally lower on the abnormal side (Fig 2). In either case, the injured vocal fold may move sluggishly or be immobile. Rarel3~ abduction and adduction may appear almost normal under continuous light. Video documentation of the preoperative and postoperative appearance can prove particularly helpful in cases of arytenoid dislocation not only diagnostically, but also because many of these patients are involved in litigation related to their injuries. The most valuable tests are the stroboscopic examination to visualize differences in vocal process height; computed tomography (CT) scan of the larynx, which should image the arytenoid dislocation and reveal clouding or obliteration of the cricoarytenoid joint space; and laryngeal electromyography to differentiate an immobile dislocated arytenoid joint from vocal fold paralysis. Airflow analysis is also helpful in documenting changes before and after therapy. Strobovideolaryngoscopy is also important to assess other vocal fold injuries. Stiffness and scar of the musculomembranous portion of the vocal folds are found commonly in association with arytenoid dislocation. The trauma causing dislocation frequently involves considerable force that results in vocal fold hemorrhage. It is important to recog-
FIGURE 2. Typical appearance of a severe anterior dislocation. The left arytenoid is tilted forward, and the vocal process pulls the vocal fold to a lower level (arrow), so the mobile right vocal fold overlaps the abnormal side during adduction. (Reprinted with permission from Sataloff RT: Professional Voice: Science and Art of Clinical Care (ed 2). Singular Publishing Group, San Diego, CA, 1997, p 536.) ROBERT THAYER SATALOFF
197
nize the presence of vocal fold scar before reducing an arytenoid dislocation to inform the patient about reasonable expectations for surgical outcome. When the author reported his series of 26 cases in 1994, only 31 additional cases had been reported in the literature. 2 Since that time, additional cases have been documented. 11-2°Although anterior and posterior dislocations are described most commonly, it has been noted previously that the arytenoid can be dislocated in any direction. 2 Complex dislocations have been observed in some of the more than 24 patients cared for by the author since his last report. Posterior dislocation is commonly an extubation injury. The arytenoid is displaced posterolaterally, and the vocal process is high and laterally positioned. Anterior dislocation is most commonly caused by intubation. The laryngoscope engages the posterior lip of the arytenoid, tearing the posterior cricoarytenoid ligament and tipping the arytenoid anteromedially (Fig 3). The vocal process ordinarily is lower than normal in such cases. Complex arytenoid dislocations can be particularly challenging. In our more recent (unreported) cases, direct anterior dislocation has been seen in two patients. In these cases, the arytenoid is anteriorly displaced, but the vocal process is high. This injury requires considerable trauma, with disruption of cartilage. Both cases have followed intubation. With injury of this severity, endoscopic reduction has been less satisfactory than with more typical anterior or posterior dislocations.
TECHNIQUES FOR SURGICAL OF ARYTENOID DISLOCATION
REDUCTION
Although early spontaneous reduction of arytenoid dislocation has been reported, 2 surgical reduction is generally required. Voice therapy for at least a brief period may be helpful in some cases, and preoperative evaluation by a speech-language pathologist is generally recommended. Surgeons should also be aware that nonsurgical approaches have been suggested. For example, Rontal and Rontal, 21 have recently introduced the concept of chemical tenotomy using botulinum toxin to enhance spontaneous reductions. In some cases, adjunct procedures performed at the time of arytenoid reduction may also be advisable, as discussed below.
FIGURE 4. Straight Miller-3 laryngoscope blade used by anesthesiologists. The curved tip with a slight lip (arrow) has proven ideal for the reduction of posterior arytenoid dislocation. (Reprinted with permission from Sataloff RT: Professional Voice: Science and Art of Clinical Care (ed 2). Singular Publishing Group, San Diego, CA, 1997, p 639.) Closed Reduction for Posterior Arytenoid Dislocation
The author has found the anesthesiologist's old-fashioned, straight, Miller-3 laryngoscope blade to be the most useful instrument for posterior arytenoid dislocation (Fig 4). The instrument is placed in the piriform sinus with the rolled tip of the laryngoscope against the infralateral edge of the dislocated cartilage (Fig 5). The surgeon's other hand is placed on the opposite side of the larynx externally to apply counterpressure. The arytenoid is distracted cranially, then manipulated anteromedially to pop the arytenoid back into position. Substantial force is often necessary. A Holinger laryngoscope is usually used to reduce anterior dislocations. More delicate instruments such as cupped forceps are not strong enough and are more likely to lacerate the mucosa and expose cartilage to the risk of infection. No instrument should be placed under the vocal process because of the risk of fracture at the embryologic
FIGURE 3. On the left, a normal larynx can be visualized from the back. The cricoarytenoid ligament is seen on both sides. The interarytenoid muscle has been removed. The posterior cricoarytenoid muscle is preserved on the right. In posterior arytenoid dislocation (center image), the posterior cricoarytenoid ligament is generally made more lax, and it is not torn. In an anterior dislocation (right image), the posterior cricoarytenoid ligament is generally torn (as illustrated) or avulsed from its insertion into the cricoid or arytenoid cartilage. 198
ARYTENOID DISLOCATION
FIGURE 5. To reduce a posterior arytenoid dislocation, the tip of a Miller-3 blade is placed in the piriform sinus (upper left). To reduce a left posterior dislocation, the laryngoscope is rotated medially (lower left) so that the lip on the laryngoscope engages the dislocated arytenoid as the laryngoscope is drawn superiorly out of the piriform sinus. Digital external counterpressure (upper left) is required, and the right hand ordinarily needs to be placed more anteriorly than illustrated in this figure. If illustrated in proper position, the hand would block visualization of the tip of the laryngoscope. Once the arytenoid has been hooked by the lip of the laryngoscope (center), considerable force is necessary to distract the arytenoid in a cephalad direction, and then to rotate it anteromedially, reducing it (right).
FIGURE 6. TO reduce an anterior dislocation, a Holinger laryngoscope is positioned (upper left). To reduce a right arytenoid dislocation, the laryngoscope is rotated about 130 ° (lower left) so that the upper surface of the laryngoscope makes broad contact with the medial surface of the dislocated arytenoid (center). The surgeon's contralateral hand is placed externally, posteriorly on the larynx (upper left) so that the arytenoid is manipulated between the laryngoscope tip and the fingers of the surgeon's right hand to reduce this right arytenoid anterior dislocation. Considerable force is required to reduce the arytenoid (right), and care must be taken not to injure or avulse the vocal process. ROBERT THAYER SATALOFF
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FIGURE 7. Digital reduction can be accomplished occasionally, especially for patients who are edentulous and who have had recent posterior dislocation or redislocation after recent arytenoid reduction. The patient's tongue is retracted by the patient or an assistant, leaving the surgeon's other hand free for external counterpressure. The surgeon's index or middle finger is placed in the piriform sinus, engaging the dislocated arytenoid (center). The surgeon's other hand applies external counterpressure, and the arytenoid is reduced digitally (right).
fusion plane between the vocal process and body of the arytenoid. The Holinger laryngoscope is rotated so that its supralateral surface makes broad contact with the anteromedial face of the arytenoid. The surgeon's other hand is placed against the larynx externally and posteriorly for manipulation and counterpressure (Fig 6). For complex dislocations, a combination of these techniques is used. It may be necessary to refracture the cartilage a n d / o r separate the joint to manipulate the arytenoid. For example, in lateral and anterolateral dislocations, it has been helpful to use the Holinger laryngoscope to disrupt the cartilage and fibrosis, bringing the arytenoid posteriorly. Then, a combination of the Holinger laryngoscope and Miller-3 laryngoscope is used to return the arytenoid to optimal position. When endoscopic closed reduction is not successful or is so unstable that dislocation recurs, open reduction and fixation should be considered. The procedure is performed using a standard arytenoid adduction rotation approach. The joint is entered. If the joint has been obliterated, a "joint" is created sharply. The arytenoid is moved to optimize vocal process position. The surgery is performed with the patient awake, and it is important to adjust vocal rocess position while the patient is phonating at his/her abitual frequency, rather than using a high-pitch / i/. Special situations and challenging clinical conditions sometimes demand other solutions to the problems of arytenoid dislocation. On three occasions, the author has used digital reduction (Fig 7). The first was on an edentulous patient in an intensive care unit who had extubated herself repeatedly. Her physicians were concerned about
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even the risk of transporting her to the operating room, let alone sedating her. Yet she had respiratory problems, and it was important to restore the efficiency of her cough. Her tongue was held with gauze in the manner of indirect laryngoscop:~ at the bedside. An assistant helped stabilize her larynx externally. A finger was placed in her pyriform sinus, and her posterior arytenoid dislocation was manually reduced. It maintained good position, and mobility returned. This technique has been used on two other patients whose arytenoids redislocated within 48 hours of surgical reduction. Most recently, another new technique was used. The author was called to see a patient who had awakened with a hoarse, weak, breathy voice and ineffective cough after anterior cervical fusion. Posterior arytenoid dislocation was diagnosed easily, and good vocal fold innervation was confirmed by electromyography. However, the patient had a short, thick neck and was flexed in a halo device, and on full-dose warfarin. In the operating room, the arytenoid was reduced indirectly under nasal fiberoptic laryngoscopic control. A right-angle bayonet forceps was used. This is the instrument that used to be used routinely for holding cocainized cotton in the pyriform sinuses to provide local anesthesia to the larynx. The tip of the forceps was covered with a red rubber catheter. The instrument was placed in the pyriform sinus, and the arytenoid was lifted cranially, anteriorly, and medially; and it popped back into position easily (Fig 8). It is worthwhile attempting endoscopic reduction even long after the injury. 1,2 In 1998 (not yet reported in detail),
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.<
FIGURE 8. This previously undescribed procedure can be used for patients with posterior arytenoid dislocation and difficult anatomical constraints, such as this patient in a halo device. A flexible laryngoscope is placed in the nostril to observe the larynx. A right-angle instrument such as a laryngeal bayonet forceps is covered with a shortened red rubber catheter. The hole in the red rubber catheter (lower left) assists in making stable contact with the dislocated arytenoid. The posterior aspect of the dislocated arytenoid is engaged (center), and drawn superiorly and anteromedially to reduce the dislocated cartilage (right).
the author successfully reduced an anterior arytenoid dislocation that had occurred 38 years previously; restoring vertical s y m m e t r y of the vocal process and fold, although thyroplasty was necessary to p r o v i d e adequate medialization.
ADJUNCTIVE MEASURES Several adjunctive m e a s u r e s should be considered w h e n p e r f o r m i n g arytenoid reduction. For a long-standing posterior dislocation, especially w h e n the reduction seems unstable, s i m u l t a n e o u s medialization should be considered. T h y r o p l a s t y or injection of a u t o l o g o u s fat or collagen not only helps medialize the vocal fold, but also tends to pull the vocal process forward. This helps m a i n t a i n the desired arytenoid position. After anterior dislocation, Rontal a n d Rontal h a v e suggested b o t u l i n u m toxin injection into a d d u c t o r muscles that tend to pull the arytenoid forward. 21 In fact, they h a v e suggested that b o t u l i n u m toxin alone m a y result in spontaneous reduction w i t h o u t the need for surgical intervention. In this a u t h o r ' s opinion, although this m a y be true in s o m e cases, it is not likely to occur once the joint has b e e n fibrosed. More investigation of this novel concept is certainly warranted.
CONCLUSION A r y t e n o i d dislocation is not rare, a l t h o u g h it is often diagnosed incorrectly. A l t h o u g h the goal of treatment is restoration of n o r m a l position and function, this cannot always be achieved. However, e v e n correcting the vertical height a b n o r m a l i t y is worthwhile. Essentially, this simpli-
ROBERT THAYER SATALOFF
ties the problem, converting it to one that can be m a n a g e d easily b y standard medialization surgery. It is essential for the surgeon to u n d e r s t a n d the a n a t o m y and surgical principles involved, because visualization d u r i n g these p r o c e d u r e s is extremely limited, and considerable force is required. In virtually all cases, the patient's voice can be i m p r o v e d , and a i r w a y p r o b l e m s and other significant complications h a v e not b e e n e n c o u n t e r e d thus far.
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12. Szigeti CL, Baeuerle JJ, Mongan PD: Arytenoid dislocation with lighted stylet intubation: case report and retrospective review. Anesth Analg 78:185-186, 1994 13. Alexander AE Jr, Lyons GD, Fazekas-May MA, et al: Utility of helical computed tomography in the study of arytenoid dislocation and arytenoid subluxation. Ann Otol Rhinol Laryngo1160:1020-1023, 1997 14. Gauss A, Treiber HS, Haehnel J, et ah Spontaneous reposition of a dislocated arytenoid cartilage. Br J Anaesth 70:591-592, 1993 15. Hsu CS, Huang CT, So EC, et al: Arytenoid subluxation following endotracheal intubation--a case report. Acta Anaesthesiol Sin 33:4552, 1995 16. Hass I, Gross M: Intubation trauma of the larynx--a literature review
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with special reference to arytenoid cartilage dislocation. Anasthesiol Intensivmed Notfallmed Schmerzther 31:279-280, 1996 Friedberg J, Giberson W: Failed tracheotomy decannulation in children. J Otolaryngo121:404-408,1992 Talmi YP, Wolf M, Bar-Ziv J, et al: Postintubation arytenoid subluxation. Ann Otol Rhinol Laryngo1105:384-390, 1996 Stack BC Jr, Ridley MB: Arytenoid subluxation from blunt laryngeal trauma. Am J Otolaryngo115:68-73,1994 Hiong YT, Fung CF, Sudhaman DA: Arytenoid subluxation: implications for the anaesthetist. Anaesth Intens Care 24:609-610, 1996 Rontal E, Rontal M: Laryngeal rebalancing in the treatment of anteromedial dislocation of the arytenoids. J Voice 12:383-388,1998
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