Acta Oto-Laryngologica. 2015; 135: 640–644
ORIGINAL ARTICLE
Transtympanic dilatation of the eustachian tube during chronic ear surgery
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
MUAAZ TARABICHI & MURTAZA NAJMI Department of Otolaryngology, American Hospital Dubai, Dubai, United Arab Emirates
Abstract Conclusion: Evaluation of the protympanic segment of the eustachian tube is feasible during chronic ear surgery. Balloon dilatation of that segment yields a bigger aperture. Objective: To evaluate the feasibility of visualization and balloon dilatation of the protympanic segment of the eustachian tube during chronic ear surgery. Methods: This study was carried out on a consecutive case series. All patients undergoing surgical treatment for cholesteatoma or tympanic membrane perforation over a 6-month period of time at a tertiary hospital were evaluated intraoperatively for the ability to visualize the protympanic segment of the eustachian tube, perform balloon dilatation, and then perform visual inspection of the effect of dilatation. Results: A total of 21 chronic ear procedures were performed; visualization of the protympanic segment was feasible in 12 ears, obstruction was identified in 7 ears, and dilatation was undertaken. Immediate assessment showed increased aperture of the tube in all patients when compared with predilatation findings.
Keywords: Cholesteatoma, tympanic perforation, balloon dilatation
Introduction Balloon dilatation of the eustachian tube has been reported with a significant degree of success and patient safety [1]. Instrumentation of the eustachian tube is performed by introducing the balloon catheter through the nasopharyngeal opening of the tube and subsequently dilating the cartilaginous segment of the tube [2]. Safety considerations in regard to avoiding possible injury to the carotid artery have limited the area of instrumentation to the distal end of the tube, probably the most commonly obstructed segment. Other sites of obstruction in the proximal area of the eustachian tube had been reported in patients undergoing chronic ear surgery [3]. Endoscopic ear surgery allows for access and visualization of the protympanic segment of the eustachian tube including the carotid canal [4]. Transtympanic introduction of the balloon catheter beyond the carotid canal into the cartilaginous eustachian tube would assure the safety of the dilatation along with the coverage of a
wider segment of the cartilaginous tube. This report describes the authors’ experience with transtympanic evaluation and dilatation of the eustachian tube in patients undergoing chronic ear surgery. Material and methods Over a 6-month period of time, patients undergoing endoscopic surgery for cholesteatoma or for grafting of the tympanic membrane gave consent to participation in this study. Intraoperatively, and during the course of routine surgical intervention, endoscopic evaluation of the protympanic segment of the eustachian tube was attempted using a 30 , 3 mm, 15 cm rigid endoscope that was introduced anterior to the handle of the malleus if that area was perforated to start with or exposed during the course of surgical intervention. After introduction of the endoscope, the protympanic segment was assessed for clear impression of the carotid artery canal and for evidence of obstruction beyond that canal within the proximal
Correspondence: Muaaz Tarabichi, MD, Department of Otolaryngology, American Hospital Dubai, PO Box 5566, Oud Mehta Road, Dubai, United Arab Emirates. Tel: +971 4 377 6999. Fax: +971 4 3776285. E-mail: [email protected]
(Received 16 November 2014; accepted 6 January 2015) ISSN 0001-6489 print/ISSN 1651-2251 online Ó 2015 Informa Healthcare DOI: 10.3109/00016489.2015.1009640
Transtympanic eustachian tube dilatation
641
L
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
M
Figure 1. Right ear: view of the obstructed protympanic segment of the eustachian tube. L, Lateral; M, Medial.
cartilaginous segment of the tube. Patients in whom a clear anatomical impression of the carotid artery canal and with an obstruction anterior to the carotid artery was observed underwent dilatation using balloon catheters (Figure 1). A eustachian tube balloon dilatation catheter (Spiggle & Theis, Overath, Germany) was used without its introducer. This catheter, with a balloon at its distal tip, was pushed through the eustachian tube opening under endoscopic guidance and carefully advanced into the tube without undue force. Once the balloon was positioned inside the tube and beyond the carotid canal, a saline solution was used to dilate up to a pressure of 10 bar (Figure 2). Pressure was maintained for 2 min. Then the solution was aspirated from the balloon and the catheter was carefully removed under endoscopic guidance. Evaluation of the post-dilated eustachian tube was performed using the same scope placed at the same area (Figure 3). Appropriate reconstruction of the
Figure 2. Right ear: balloon dilatation of the eustachian tube using a balloon catheter. L, Lateral; M, Medial.
Figure 3. Right ear: post-dilatation view of the protympanic segment of the eustachian tube; the downward and anterior turn of the tube can now be visualized after dilatation. L, Lateral; M, Medial.
tympanic membrane and ossicular chain was performed. Follow-up was performed with visual assessment using the microscope and by asking patients in regard to the ability to equalize pressure with the Valsalva maneuver as well as the presence of any ear pressure symptoms. The Research and Ethics Committee at the American Hospital Dubai approved the study and informed consent was obtained. Results During a 6-month period of time, 21 procedures were performed for cholesteatoma or tympanic perforation. Of that number, endoscopic evaluation of the protympanic segment of the eustachian tube was possible in only 12 ears without the need for any further dissection or disruption of the anatomy. The most common cause of the failure to visualize was a posterior limited perforation and intact anterior tympanic membrane, which was the case in seven ears. In two other ears, isolated attic cholesteatoma with normal parse tensa was present and visualization was not possible without taking surgical steps that would not have been done in the standard course of the surgical treatment of those cases. There were 12 ears where the protympanic segment was visualized; this group included 10 subtotal perforations and 2 patients with mesotympanic cholesteatoma. In all these patients a clear impression of the carotid canal on the medial wall of the protympanic segment was obtained, and there was no obstruction in the area of the carotid canal. Clear obstruction was identified anterior to the carotid canal in the 2 patients with mesotympanic cholesteatoma and in 6 of 10 ears with subtotal perforation. Balloon dilatation was
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
642
M. Tarabichi & M. Najmi
performed in all eight patients with obstruction by introducing the catheter through the protympanic opening of the eustachian tube. All patients had a clear change in the aperture of the tube after the dilatation, with no clear bleeding or major mucosal trauma. Only three patients underwent postoperative CT of the ear with multiplanar reconstruction to visualize the eustachian tube. Clear differences between preoperative and postoperative CT images were identified in two of these three patients (Figures 4 and 5). The average follow-up for the dilated group was 4 months, with one patient lost to follow-up after 3 weeks. Six of seven patients undergoing dilatation had closure of perforation and no recurrent retraction or cholesteatoma and the tympanic membrane was in a neutral-appearing position without any retraction or evidence of middle ear effusion. In one patient, there was residual small perforation along with draining ear in the immediate postoperative period and the perforation persisted at 3 months follow-up after the ear was dry. All seven patients with follow-up reported no pressure symptoms in the ear. Five of six patients with intact tympanic membrane reported the ability to ‘pop their ears’ with the Valsalva maneuver since the surgery. Only three of six demonstrated clear movement of the tympanic membrane with the Valsalva maneuver during microscopic examination on the last follow-up visit. Discussion Chronic ear surgery has always revolved around removing disease and regaining function, without much attention to the pathophysiologic process underlying the disease. Since much of the obstruction sites lie out of reach of our traditional instruments, it is always assumed that time and age have resolved any
Figure 4. Preoperative CT image of the protympanic segment of the eustachian tube.
Figure 5. Postoperative CT image of the protympanic segment in the same patient as in Figure 4 at 3 months after intervention.
obstruction [3]. Failures in chronic ear surgery have been shown to correlate with persistent eustachian tube dysfunction [5]. The preponderance of evidence seem to indicate that the cartilaginous tube and it distal segment harbor most of the sites of obstruction [6–8]. However, it stands to reason that there is a degree of variability in the site of obstruction and that some of our patients do have obstruction in other more proximal locations in the eustachian tube, in close proximity to the tympanic cavity and any recurrent inflammatory process within it. Linstrom et al. [3] described their experience in using fiberoptic flexible mini scopes introduced through the ear during chronic ear surgery to evaluate the patency of the eustachian tube. Their results indicated that much of the obstruction existed in the protympanic segment of the eustachian tube. They also found that in cases where the obstruction could be bypassed, the obstructed segment did not extend much beyond that point [3]. However, it should be indicated that the quality of the images obtained with the fiberoptic device they used was very limited, which can lead to misleading assessment of these images. In contrast, endoscopic ear surgery with rigid scopes allows the high-resolution evaluation and instrumentation of the protympanic segment of the tube [4]. Recently, balloon dilatation of the eustachian tube has been described with a significant degree of success. The procedure is designed to address obstruction located in the distal segment of the cartilaginous segment in proximity to the nasopharyngeal opening of the eustachian tube [1,2]. The procedure is performed by introducing a balloon dilatation catheter through the nasopharyngeal opening of the tube with design features that prevent its introduction to the
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
Transtympanic eustachian tube dilatation area in proximity to the carotid artery canal. The procedure and the catheters are designed to stay well clear of the protympanic segment of the tube, an area that might harbor the obstruction site. The term ‘protympanic segment’ of the eustachian tube is nonspecific and is used in this paper to describe the segment of the eustachian tube that can be visualized by introducing the 30 angle scope into the anterior tympanic cavity. It can be divided into two areas, the area medial to the carotid canal and the area anterior to that. The carotid canal is uniformly identifiable by expert inspection of the protympanic segment and the end carotid canal anteriorly seems to delineate the beginning point of the cartilaginous segment of the eustachian tube (Figure 6). In most cases, a significant segment of the proximal cartilaginous tube can be visualized and that is part of what we consider the ‘protympanic segment’ of the eustachian tube and is the site of the described obstruction and attempted dilatation. Endoscopic ear surgery with rigid straight and angled view scopes allows for wide view visualization of the tympanic cavity, especially anteriorly [9]. Further exposure anteriorly into the protympanic part of the eustachian tube can be obtained with a 30 , 3 mm endoscope. This allows the visualization of much of the bony segment and a significant part of the cartilaginous segment as it turns inferiorly and medially at an almost 120 angle to the bony segment [10]. This visualization is conditioned on the ability to introduce the endoscope anterior to the handle of the malleus. Access can also be obtained even with intact tympanic membrane anteriorly by separating the membrane from the handle of the malleus and lifting it up anteriorly against the anterior ear canal. In the present
643
study, we were only able to visualize the area in 9 of 21 patients because the ethics committee at our institution conditioned its approval of the study on the fact that no extra intervention would take place to visualize the eustachian tube other than would have otherwise happened in the standard course of treatment of these patients. The site of the obstruction in all of these cases has consistently been in the pre-carotid segment of the eustachian tube, at the proximal end of the cartilaginous tube. It has also been a consistent finding that the post-dilatation picture looked very different, with clear widening of the aperture of that segment when compared with the predilatation findings, confirming the cartilaginous nature of that segment anterior to the carotid canal. The safety of the carotid and its canal can be ascertained due to the consistency of the identification of the carotid canal in the medial wall of the protympanum that was observed here and the introduction of the balloon catheter beyond that point. The anatomy of the protympanic segment of the eustachian tube is variable and clear understanding of that anatomy and full visualization are preconditions for safe instrumentation of the proximal end the eustachian tube. In about 30% of the ears examined, there was a pneumatization of the space in the area anterior to the carotid, which resulted in a ridge of bone that separated the protympanic opening of the eustachian tube into a medial opening for the eustachian tube and a lateral false passage (Figure 6). This requires the surgeon to introduce a small scope far enough anteriorly to determine the exact anatomy of that area (Figures 7 and 8). If the false passage is cannulated, and if the surgeon fails to clearly identify the carotid canal and then to make sure that the dilatation is undertaken in
PET
EC
FP ET
Figure 6. Axial histologic section of the temporal bone with the cochlea and malleus simulated for orientation. Note the pneumatization and formation of a medial false passage. ET, eustachian tube; FP, false passage.
Figure 7. Right ear: the protympanum is visualized after lifting of the tympanic membrane off the handle of the malleus. An apparent opening of the eustachian tube is visualized.
644
M. Tarabichi & M. Najmi
ET
with clear widening of the obstructed areas. There is anecdotal radiologic evidence that such widening is evident 3 months after the intervention. The present study aimed to assess the technical feasibility of such intervention using an endoscopic technique. The small number of subjects studied would preclude any conclusion on the expected outcome. Further studies of the impact of this intervention on the outcome of the surgical management of chronic ear disease should be undertaken.
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
FP
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Figure 8. Further introduction of the scope shows the true opening of the eustachian tube laterally to a false passage that was initially thought to be the opening of the tube. ET, eustachian tube; FP, false passage.
the cartilaginous segment of the eustachian tube anterior to the canal, one can see the possibility of damaging the carotid canal (Figure 6). Multiplanar reconstruction of high-resolution CT images of the temporal bone has allowed the orientation of the sections in the plane of the eustachian tube and the ability to bring it to view. Careful study of these images in the axis of the tube would result in better understanding of the anatomy of the proximal segment. Preoperative CT is common practice in cholesteatoma surgery and careful attention to the eustachian tube anatomy and pathology should be part of any preoperative assessment of these patients. Conclusion The endoscopic technique allows visualization of the protympanic segment of the eustachian tube in selected patients undergoing chronic ear surgery. Balloon dilatation of the area can be undertaken
References [1] Poe DS, Juha S, Ilmari P. Balloon dilation of the cartilaginous Eustachian tube. Otolaryngol Head Neck Surg 2011;144: 563–9. [2] Ockermann T, Ulf R, Tahwinder U, Jörg E, Holger HS. Balloon dilatation eustachian tuboplasty: a clinical study. Laryngoscope 2010;120:1411–16. [3] Linstrom CJ, Carol AS, Arie R, Lawrence ZM. Eustachian tube endoscopy in patients with chronic ear disease. Laryngoscope 2000;110:1884–9. [4] Tarabichi M. Transcanal endoscopic management of cholesteatoma. Otol Neurotol 2010;31:580–8. [5] Sato H, Hajime N, Iwao H, Masahiko H. Eustachian tube function in tympanoplasty. Acta Otolaryngol 1990;110:9–12. [6] Takahashi H, Fujita A, Honjo I. Site of eustachian tube dysfunction in patients with otitis media with effusion. Am J Otolaryngol 1987;8:361–3. [7] Edelstein DR, Magnan J, Parisier C. Microfiberoptic evaluation of the middle ear cavity. Am J Otol 1994;15:50–5. [8] Takahashi H, Honjo I, Fujita A. Endoscopic findings at the pharyngeal orifice of the Eustachian tube in otitis media with effusion. Eur Arch Otorhinolaryngol 1996;253:42–7. [9] Tarabichi M. Endoscopic management of limited attic cholesteatoma. Laryngoscope 2004;114:1157–62. [10] Graves GO, Edwards LF. The Eustachian tube: review of its descriptive, microscopic, topographic, and clinical anatomy. Arch Otolaryngol 1944;39:359–97.
ORIGINAL ARTICLE
Transtympanic dilatation of the eustachian tube during chronic ear surgery
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
MUAAZ TARABICHI & MURTAZA NAJMI Department of Otolaryngology, American Hospital Dubai, Dubai, United Arab Emirates
Abstract Conclusion: Evaluation of the protympanic segment of the eustachian tube is feasible during chronic ear surgery. Balloon dilatation of that segment yields a bigger aperture. Objective: To evaluate the feasibility of visualization and balloon dilatation of the protympanic segment of the eustachian tube during chronic ear surgery. Methods: This study was carried out on a consecutive case series. All patients undergoing surgical treatment for cholesteatoma or tympanic membrane perforation over a 6-month period of time at a tertiary hospital were evaluated intraoperatively for the ability to visualize the protympanic segment of the eustachian tube, perform balloon dilatation, and then perform visual inspection of the effect of dilatation. Results: A total of 21 chronic ear procedures were performed; visualization of the protympanic segment was feasible in 12 ears, obstruction was identified in 7 ears, and dilatation was undertaken. Immediate assessment showed increased aperture of the tube in all patients when compared with predilatation findings.
Keywords: Cholesteatoma, tympanic perforation, balloon dilatation
Introduction Balloon dilatation of the eustachian tube has been reported with a significant degree of success and patient safety [1]. Instrumentation of the eustachian tube is performed by introducing the balloon catheter through the nasopharyngeal opening of the tube and subsequently dilating the cartilaginous segment of the tube [2]. Safety considerations in regard to avoiding possible injury to the carotid artery have limited the area of instrumentation to the distal end of the tube, probably the most commonly obstructed segment. Other sites of obstruction in the proximal area of the eustachian tube had been reported in patients undergoing chronic ear surgery [3]. Endoscopic ear surgery allows for access and visualization of the protympanic segment of the eustachian tube including the carotid canal [4]. Transtympanic introduction of the balloon catheter beyond the carotid canal into the cartilaginous eustachian tube would assure the safety of the dilatation along with the coverage of a
wider segment of the cartilaginous tube. This report describes the authors’ experience with transtympanic evaluation and dilatation of the eustachian tube in patients undergoing chronic ear surgery. Material and methods Over a 6-month period of time, patients undergoing endoscopic surgery for cholesteatoma or for grafting of the tympanic membrane gave consent to participation in this study. Intraoperatively, and during the course of routine surgical intervention, endoscopic evaluation of the protympanic segment of the eustachian tube was attempted using a 30 , 3 mm, 15 cm rigid endoscope that was introduced anterior to the handle of the malleus if that area was perforated to start with or exposed during the course of surgical intervention. After introduction of the endoscope, the protympanic segment was assessed for clear impression of the carotid artery canal and for evidence of obstruction beyond that canal within the proximal
Correspondence: Muaaz Tarabichi, MD, Department of Otolaryngology, American Hospital Dubai, PO Box 5566, Oud Mehta Road, Dubai, United Arab Emirates. Tel: +971 4 377 6999. Fax: +971 4 3776285. E-mail: [email protected]
(Received 16 November 2014; accepted 6 January 2015) ISSN 0001-6489 print/ISSN 1651-2251 online Ó 2015 Informa Healthcare DOI: 10.3109/00016489.2015.1009640
Transtympanic eustachian tube dilatation
641
L
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
M
Figure 1. Right ear: view of the obstructed protympanic segment of the eustachian tube. L, Lateral; M, Medial.
cartilaginous segment of the tube. Patients in whom a clear anatomical impression of the carotid artery canal and with an obstruction anterior to the carotid artery was observed underwent dilatation using balloon catheters (Figure 1). A eustachian tube balloon dilatation catheter (Spiggle & Theis, Overath, Germany) was used without its introducer. This catheter, with a balloon at its distal tip, was pushed through the eustachian tube opening under endoscopic guidance and carefully advanced into the tube without undue force. Once the balloon was positioned inside the tube and beyond the carotid canal, a saline solution was used to dilate up to a pressure of 10 bar (Figure 2). Pressure was maintained for 2 min. Then the solution was aspirated from the balloon and the catheter was carefully removed under endoscopic guidance. Evaluation of the post-dilated eustachian tube was performed using the same scope placed at the same area (Figure 3). Appropriate reconstruction of the
Figure 2. Right ear: balloon dilatation of the eustachian tube using a balloon catheter. L, Lateral; M, Medial.
Figure 3. Right ear: post-dilatation view of the protympanic segment of the eustachian tube; the downward and anterior turn of the tube can now be visualized after dilatation. L, Lateral; M, Medial.
tympanic membrane and ossicular chain was performed. Follow-up was performed with visual assessment using the microscope and by asking patients in regard to the ability to equalize pressure with the Valsalva maneuver as well as the presence of any ear pressure symptoms. The Research and Ethics Committee at the American Hospital Dubai approved the study and informed consent was obtained. Results During a 6-month period of time, 21 procedures were performed for cholesteatoma or tympanic perforation. Of that number, endoscopic evaluation of the protympanic segment of the eustachian tube was possible in only 12 ears without the need for any further dissection or disruption of the anatomy. The most common cause of the failure to visualize was a posterior limited perforation and intact anterior tympanic membrane, which was the case in seven ears. In two other ears, isolated attic cholesteatoma with normal parse tensa was present and visualization was not possible without taking surgical steps that would not have been done in the standard course of the surgical treatment of those cases. There were 12 ears where the protympanic segment was visualized; this group included 10 subtotal perforations and 2 patients with mesotympanic cholesteatoma. In all these patients a clear impression of the carotid canal on the medial wall of the protympanic segment was obtained, and there was no obstruction in the area of the carotid canal. Clear obstruction was identified anterior to the carotid canal in the 2 patients with mesotympanic cholesteatoma and in 6 of 10 ears with subtotal perforation. Balloon dilatation was
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
642
M. Tarabichi & M. Najmi
performed in all eight patients with obstruction by introducing the catheter through the protympanic opening of the eustachian tube. All patients had a clear change in the aperture of the tube after the dilatation, with no clear bleeding or major mucosal trauma. Only three patients underwent postoperative CT of the ear with multiplanar reconstruction to visualize the eustachian tube. Clear differences between preoperative and postoperative CT images were identified in two of these three patients (Figures 4 and 5). The average follow-up for the dilated group was 4 months, with one patient lost to follow-up after 3 weeks. Six of seven patients undergoing dilatation had closure of perforation and no recurrent retraction or cholesteatoma and the tympanic membrane was in a neutral-appearing position without any retraction or evidence of middle ear effusion. In one patient, there was residual small perforation along with draining ear in the immediate postoperative period and the perforation persisted at 3 months follow-up after the ear was dry. All seven patients with follow-up reported no pressure symptoms in the ear. Five of six patients with intact tympanic membrane reported the ability to ‘pop their ears’ with the Valsalva maneuver since the surgery. Only three of six demonstrated clear movement of the tympanic membrane with the Valsalva maneuver during microscopic examination on the last follow-up visit. Discussion Chronic ear surgery has always revolved around removing disease and regaining function, without much attention to the pathophysiologic process underlying the disease. Since much of the obstruction sites lie out of reach of our traditional instruments, it is always assumed that time and age have resolved any
Figure 4. Preoperative CT image of the protympanic segment of the eustachian tube.
Figure 5. Postoperative CT image of the protympanic segment in the same patient as in Figure 4 at 3 months after intervention.
obstruction [3]. Failures in chronic ear surgery have been shown to correlate with persistent eustachian tube dysfunction [5]. The preponderance of evidence seem to indicate that the cartilaginous tube and it distal segment harbor most of the sites of obstruction [6–8]. However, it stands to reason that there is a degree of variability in the site of obstruction and that some of our patients do have obstruction in other more proximal locations in the eustachian tube, in close proximity to the tympanic cavity and any recurrent inflammatory process within it. Linstrom et al. [3] described their experience in using fiberoptic flexible mini scopes introduced through the ear during chronic ear surgery to evaluate the patency of the eustachian tube. Their results indicated that much of the obstruction existed in the protympanic segment of the eustachian tube. They also found that in cases where the obstruction could be bypassed, the obstructed segment did not extend much beyond that point [3]. However, it should be indicated that the quality of the images obtained with the fiberoptic device they used was very limited, which can lead to misleading assessment of these images. In contrast, endoscopic ear surgery with rigid scopes allows the high-resolution evaluation and instrumentation of the protympanic segment of the tube [4]. Recently, balloon dilatation of the eustachian tube has been described with a significant degree of success. The procedure is designed to address obstruction located in the distal segment of the cartilaginous segment in proximity to the nasopharyngeal opening of the eustachian tube [1,2]. The procedure is performed by introducing a balloon dilatation catheter through the nasopharyngeal opening of the tube with design features that prevent its introduction to the
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
Transtympanic eustachian tube dilatation area in proximity to the carotid artery canal. The procedure and the catheters are designed to stay well clear of the protympanic segment of the tube, an area that might harbor the obstruction site. The term ‘protympanic segment’ of the eustachian tube is nonspecific and is used in this paper to describe the segment of the eustachian tube that can be visualized by introducing the 30 angle scope into the anterior tympanic cavity. It can be divided into two areas, the area medial to the carotid canal and the area anterior to that. The carotid canal is uniformly identifiable by expert inspection of the protympanic segment and the end carotid canal anteriorly seems to delineate the beginning point of the cartilaginous segment of the eustachian tube (Figure 6). In most cases, a significant segment of the proximal cartilaginous tube can be visualized and that is part of what we consider the ‘protympanic segment’ of the eustachian tube and is the site of the described obstruction and attempted dilatation. Endoscopic ear surgery with rigid straight and angled view scopes allows for wide view visualization of the tympanic cavity, especially anteriorly [9]. Further exposure anteriorly into the protympanic part of the eustachian tube can be obtained with a 30 , 3 mm endoscope. This allows the visualization of much of the bony segment and a significant part of the cartilaginous segment as it turns inferiorly and medially at an almost 120 angle to the bony segment [10]. This visualization is conditioned on the ability to introduce the endoscope anterior to the handle of the malleus. Access can also be obtained even with intact tympanic membrane anteriorly by separating the membrane from the handle of the malleus and lifting it up anteriorly against the anterior ear canal. In the present
643
study, we were only able to visualize the area in 9 of 21 patients because the ethics committee at our institution conditioned its approval of the study on the fact that no extra intervention would take place to visualize the eustachian tube other than would have otherwise happened in the standard course of treatment of these patients. The site of the obstruction in all of these cases has consistently been in the pre-carotid segment of the eustachian tube, at the proximal end of the cartilaginous tube. It has also been a consistent finding that the post-dilatation picture looked very different, with clear widening of the aperture of that segment when compared with the predilatation findings, confirming the cartilaginous nature of that segment anterior to the carotid canal. The safety of the carotid and its canal can be ascertained due to the consistency of the identification of the carotid canal in the medial wall of the protympanum that was observed here and the introduction of the balloon catheter beyond that point. The anatomy of the protympanic segment of the eustachian tube is variable and clear understanding of that anatomy and full visualization are preconditions for safe instrumentation of the proximal end the eustachian tube. In about 30% of the ears examined, there was a pneumatization of the space in the area anterior to the carotid, which resulted in a ridge of bone that separated the protympanic opening of the eustachian tube into a medial opening for the eustachian tube and a lateral false passage (Figure 6). This requires the surgeon to introduce a small scope far enough anteriorly to determine the exact anatomy of that area (Figures 7 and 8). If the false passage is cannulated, and if the surgeon fails to clearly identify the carotid canal and then to make sure that the dilatation is undertaken in
PET
EC
FP ET
Figure 6. Axial histologic section of the temporal bone with the cochlea and malleus simulated for orientation. Note the pneumatization and formation of a medial false passage. ET, eustachian tube; FP, false passage.
Figure 7. Right ear: the protympanum is visualized after lifting of the tympanic membrane off the handle of the malleus. An apparent opening of the eustachian tube is visualized.
644
M. Tarabichi & M. Najmi
ET
with clear widening of the obstructed areas. There is anecdotal radiologic evidence that such widening is evident 3 months after the intervention. The present study aimed to assess the technical feasibility of such intervention using an endoscopic technique. The small number of subjects studied would preclude any conclusion on the expected outcome. Further studies of the impact of this intervention on the outcome of the surgical management of chronic ear disease should be undertaken.
Acta Otolaryngol Downloaded from informahealthcare.com by Nyu Medical Center on 06/13/15 For personal use only.
FP
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. Figure 8. Further introduction of the scope shows the true opening of the eustachian tube laterally to a false passage that was initially thought to be the opening of the tube. ET, eustachian tube; FP, false passage.
the cartilaginous segment of the eustachian tube anterior to the canal, one can see the possibility of damaging the carotid canal (Figure 6). Multiplanar reconstruction of high-resolution CT images of the temporal bone has allowed the orientation of the sections in the plane of the eustachian tube and the ability to bring it to view. Careful study of these images in the axis of the tube would result in better understanding of the anatomy of the proximal segment. Preoperative CT is common practice in cholesteatoma surgery and careful attention to the eustachian tube anatomy and pathology should be part of any preoperative assessment of these patients. Conclusion The endoscopic technique allows visualization of the protympanic segment of the eustachian tube in selected patients undergoing chronic ear surgery. Balloon dilatation of the area can be undertaken
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