Otology & Neurotology 35:101Y107 Ó 2013, Otology & Neurotology, Inc.
Extension of Indications for Transcanal Endoscopic Ear Surgery Using an Ultrasonic Bone Curette for Cholesteatomas Seiji Kakehata, Tomoo Watanabe, Tsukasa Ito, Toshinori Kubota, and Takatoshi Furukawa Department of Otolaryngology, Head and Neck Surgery, Yamagata University Faculty of Medicine, Yamagata, Japan
UBC prevents injury to the tympanomeatal flap and other soft tissue, which may result with standard drills. Transcanal endoscopic retrograde mastoidectomy on demand was performed to access the pathologies in the attic and antrum. Results: A minimum attico-antrotomy was performed using the UBC, removing only the bony tissue necessary to visualize the pathology. The cholesteatoma was completely removed from the antral mucosa under clear endoscopic visualization in 13 of 14 cases. After removal of the cholesteatoma, the canal wall was reconstructed using cartilage taken from the tragus. This procedure resulted in greater mastoid preservation. Conclusion: The transcanal endoscopic approach to the antrum using the UBC proved to be less invasive and more functional. The UBC contains both a suction and irrigation system in a single handpiece, and this UBC is an appropriate cutting tool that extends the indications for TEES. Key Words: CholesteatomaVLess invasive surgeryVRetrograde mastoidectomy on demandV Transcanal endoscopic ear surgeryVUltrasonic bone curette.
Background: One-handed endoscopic procedures have, up until now, limited the indications for transcanal endoscopic ear surgery (TEES) in cholesteatoma surgery. However, the development of electrically powered instruments has opened the door to such one-handed endoscopic procedures in restricted surgical spaces. Objective: We examined the feasibility of using one such powered instrument, the ultrasonic bone curette (UBC) in TEES for cholesteatoma surgery. The UBC offers several advantages, including nonrotational motion and the combination of both suction and irrigation in a single handpiece. Study Design: A prospective case series. Setting: Tertiary referral center. Patients: TEES was performed on 43 cases of primary cholesteatoma between September 2011 and December 2012, including 14 cases extending to the antrum. Intervention: Zero-, 30-, or 70-degree angled rigid endoscopes with an outer diameter of 2.7 mm (Karl Storz) were used together with a high-definition video system. A Sonopet UBC (Stryker) was used to cut bony tissue. The nonrotational motion of the
Otol Neurotol 35:101Y107, 2014.
Transcanal endoscopic ear surgery (TEES) is a keyhole procedure (1Y5). The combination of thin rigid otoendoscopes and a full high-definition (HD) camera system facilitates a less invasive transcanal approach to the middle ear with clear and high contrast views that overcome the drawbacks of the standard 2D views of endoscopy. The endoscope offers advantages such as a wide field of view, high magnification, and fewer anatomic dead corners, and these advantages make TEES a viable candidate for tympanoplasty. TEES overcomes the drawbacks of microscopic ear surgery (MES) such as wide bone cutting and inevita-
ble anatomical dead corners. However, standard drills are difficult to use for bone cutting in TEES because of the limited working space in the external auditory canal, which is surrounded by bone. The rotating bur of standard drills can also catch the meatal skin flap. Transcanal procedures have thus been performed mainly with curettes, and the use of such curettes has limited the indications of TEES to cholesteatomas within the tympanic cavity and the attic. We have started to treat cholesteatomas using a TEES procedure called endoscopic retrograde mastoidectomy on demand together with an ultrasonic bone curette (UBC). The endoscopic retrograde mastoidectomy on demand procedure allows us to move, anatomic section by anatomic section, through the ear canal and cut only the bone up to the location of the cholesteatoma. This less invasive approach is in stark contrast to the microscopic
Address correspondence and reprint requests to Seiji Kakehata, M.D., Ph.D., Department of Otolaryngology, Head and Neck Surgery, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata, 990-9585, Japan; E-mail: [email protected] The authors disclose no conflicts of interest.
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FIG. 1. Ultrasonic bone curette, Sonopet UST-2001 (Stryker). A, Sonopet 25MA Universal Handpiece. B, The small H201 LT tip uses longitudinal-torsional compound vibrations. C, The UBC has a suction apparatus in the back of the tip.
transcortical mastoidectomy (6), which requires substantial removal of cortical bone and mucosa in the mastoid, regardless of the location of the cholesteatoma. These superior results are due, in large part, to the use of the UBC, which contains a suction-irrigation system in a single handpiece. The nonrotational motion of the UBC prevents damage to the tympanomeatal flap or other soft tissue, which a standard drill can cause (7Y10). Our TEES procedure is described herein, focusing particularly on the incorporation of the UBC into this procedure. We further show how TEES, together with the UBC, can be used to successfully treat cholesteatomas with potentially better results than conventional procedures.
Intervention Cholesteatoma surgery was performed in the ear canal completely under endoscopic visualization using TEES. 0-, 30-,
METHODS Patients Ninety-six patients underwent tympanoplasty for middle ear cholesteatoma at our institute between September 2011 and December 2012. The patients were 42 female and 54 male subjects, ranging in age from 2 to 82 years, with a mean age of 44.2 years. Among these patients, 6 presented with congenital cholesteatomas and 90 with acquired cholesteatomas, including 69 primary cases. The cholesteatoma extended to the mastoid region in 38 cases. TEES was performed on 43 cases, including 14 cases extending to the antrum. Four cases extending up to the mastoid tip were treated with a dual approach, a canal wall up procedure where TEES is combined with transcortical mastoidectomy under microscopy. The study protocol was approved in advance by the ethics committee of Yamagata University Faculty of Medicine, Yamagata, Japan.
FIG. 2. A photograph (A) and a schema (B) show the TEES procedure with the Sonopet UBC.
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EXTENSION OF INDICATIONS FOR TEES
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FIG. 3. The TEES surgical procedure (right ear). A, Surgical view with a 0-degree angled endoscope. B, Circumferential incision in the EAC. C, Elevation of the tympanomeatal flap. After checking the retrotympanum, the incudostapedial joint is cut. Note the clear view of the retrotympanum with a 0-degree angled endoscope.
or 70-degree angled rigid endoscopes with an outer diameter of 2.7 mm (Stroz, Germany) were used. Images were recorded through a full high-definition (HD) camera (Stroz, Germany), which was attached to the endoscope lens, and these images were displayed on a full HD monitor. Endoscopic transcanal retrograde mastoidectomy on demand was performed to access the pathologies in the attic and antrum.
This procedure allows for minimal removal of the bone and maximal preservation of the mucosa. A Sonopet UBC (Stryker, USA) (Fig. 1) was used to cut the bony tissue via a transcanal approach (Fig. 2). This device delivers bone cutting, irrigation, and suction simultaneously in a single handpiece, therefore making the UBC suitable for one-handed TEES. The handpiece is 130 mm in length from the tip to the angled section and 117 mm
FIG. 4. The TEES surgical procedure (continued). A, Retrograde mastoidectomy on demand with the UBC. B, A thin bony shelf is left inside. C, The bony shelf is removed with a high-speed curved bur. D, The matrix is elevated from the antrum to attic, leaving the mucosa intact using a double bent elevator. Otology & Neurotology, Vol. 35, No. 1, 2014
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in the grip section (Fig. 1A). The tip of the UBC is 1.0 1.9 3.0 mm in size and has both longitudinal and torsional (LT) movement at a frequency of 25 kHz with a maximum amplitude of 300 Km. LT oscillation allows bony tissue to be cut with no kicking or grabbing of the soft tissue. The oscillating tip is covered with a tip cover (Fig. 1B), and irrigation water flows between the tip and the cover. The water is aspirated from a suction hole on the back of the tip (Fig. 1C).
The cholesteatoma matrix from the antrum is completely removed with the matrix from the mesotympanum. After removal of the cholesteatoma, an anterior ventilation route is made to prevent cholesteatoma recurrence (Fig. 5A). Reconstruction of the ossicular chain and the bony canal wall are performed using cartilage with perichondrium harvested from the tragus (Fig. 5, B and C). The tympanomeatal flap is put back into place (Fig. 5D), and then, the EAC is packed with chitin sheets, Gelfoam sponges soaked in antibiotic eardrops, and Merocol sponges.
TEES Procedure TEES is performed under general anesthesia. A local anesthesia is administered to the bony ear canal to suppress possible bleeding and elevate the skin of the ear canal. A circumferential incision is made in the middle of the bony ear canal with a round knife (Fig. 3B). The tympanomeatal flap is lifted anteriorly, allowing a clear visualization of the tympanic cavity, including the retrotympanum (Fig. 3C). The matrix in the cavity, if present, is elevated under direct visualization. Retrograde mastoidectomy on demand is performed with the UBC starting with an atticotomy (Fig. 4, AYC). A thin bony shelf is left in the attic and antrum to protect the delicate structures until bone cutting is almost completed (Fig. 4B). A final step is to then remove this shelf with a hammer, chisels, and curettes and then polish the area with a high-speed curved bur (Fig. 4C). This procedure is performed until the edge of the cholesteatoma is visible. Once the edge is identified, the matrix is elevated from the antrum to attic, leaving the mucosa intact (Fig. 4D).
RESULTS TEES indications for cholesteatoma have been successfully expanded to cases extending up to the antrum. We selected the operative procedure presurgically based on these expanded indications for patients treated from September 2011 to December 2012. Our selection process was originally based solely on a CT evaluation, but the evaluation was revised in January 2012 to include both a CT and MRI evaluation, including EPI-DW or non-EPI-DW. This revised evaluation lead to better results, particularly in accurately estimating shadows in the mastoid, which had been overestimated in 4 early cases. Exclusion criteria are: inner ear fistula, wide exposure of the dura, and infiltrative cholesteatoma.
FIG. 5. The TEES surgical procedure (continued). Reconstruction of the ossicular chain and the bony canal wall. A, Making an anterior ventilation route. B, Insertion of the double cartilage with a dimple onto the stapes head. C, Covering the 8 5 mm defect of the EAC using cartilage with perichondrium. D, The tympanomeatal flap was put back into place. Otology & Neurotology, Vol. 35, No. 1, 2014
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EXTENSION OF INDICATIONS FOR TEES Primary Cases First-stage operations were performed in 69 of the 96 cholesteatoma cases. This group of 69 can be further divided into 30 cholesteatomas (43%), which were limited to within the tympanic cavity and/or attic while 38 (55.0%) extended to the mastoid region with 1 located in the petrous apex (Table 1). All 69 patients were presurgically evaluated for the appropriate surgical approach from among TEES, a dual TEES/MES procedure, or canal wall down (CWD). Twenty-six (86.7%) of 30 cholesteatomas up to the attic and 14 (37%) of 38 cholesteatomas extending up to the mastoid were classified as good candidates for TEES for a total of 40 cases. TEES was successfully performed in all 26 of the cholesteatomas up to the attic and 13 of 14 of the mastoid cholesteatomas. The surgical approach was switched during surgery for 1 case to a CWD procedure under microscopy because the infiltrative matrix of the cholesteatoma extended up to the mastoid tip, and new bone formations were found. Retrograde Mastoidectomy on Demand Retrograde mastoidectomy on demand was performed employing a minimum attico-antrotomy. This atticoantrotomy was performed using the UBC without difficulties in most of the 39 cases including when the cholesteatoma extended all the way to the mastoid region. The UBC greatly facilitates cutting of the bony tissue, which is blocking visualization of the diseased area including the cholesteatoma itself, effusions, and granulations. The necessary bony tissue is cut, and an opening not exceeding 10 mm in length is fashioned by the UBC. The cholesteatoma matrix can then be continuously elevated while leaving the mucosa intact. The matrix is removed, ideally in one piece, but occasionally in a small number of large pieces from the antrum to the attic using a double bent elevator and curved suction tubes. The surgical field is kept clear by stopping any hemorrhaging using neurosurgical sponges, Bemsheets, which are soaked in epinephrine. Effusions in the peripheral mastoid cells were suctioned with several types of bent suction tubes. Granulations were removed as much as possible with bent elevators and the suction tubes. The 30- or 70-degree angled endoscopes were used to confirm that no cholesteatoma residue remained in the mastoid. However, a number of issues need to be kept in mind and dealt with as necessary during surgery. First, the outer TABLE 1. Surgical procedures and anatomaic locations of cholesteatomas between September 2011 and December 2012
TEES Dual (TEES+MES) MES (CWD) Total
TA
M
Others
Total
26 0 4 30
13 4 21 38
0 0 1 1
39 4 26 69
CWD indicates canal wall down; M, mastoid; MES, microscopic ear surgery; TA, tympanic cavity and/or attic; TEES, transcanal endoscopic ear surgery.
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covering of the UBC may be too thick to allow access to the deepest areas such as the supratubal recess in patients with a narrow EAC. In addition, the amount of irrigation water and degree of suction needs to be carefully set to obtain a clear endoscopic view. Finally, the tympanomeatal flap can be caught up by the UBC suction, but this problem can be averted by placing a piece of sterile paper on the tympanomeatal flap creating a protective barrier. The ease of this surgery can be largely attributed to the preservation of a thin bony shelf within the ear canal to prevent unexpected injury to important structures such as the ossicles, facial nerve, and inner ear. Once the bone cutting is nearly completed, this shelf is removed with a hammer, chisels and/or curettes, and then smoothed with a high-speed curved diamond bur. Finally, the opening created by the UBC through which the cholesteatoma matrix was removed is repaired using cartilage from the tragus.
DISCUSSION The use of a powered instrument such as a UBC with TEES is reported herein for the first time in cholesteatoma surgery. TEES allows all aspects of surgery to be performed in the external and middle ear under endoscopy, and TEES is a less invasive surgical procedure with minimal pain, no auricular numbness, no auricular displacement, and reduced hospitalization. However, several drawbacks of TEES such as the 2D image, one-handed surgery, and limitations of bone cutting have impacted the adoption of this procedure. Advances in technology, specifically the development of a full HD camera system, have resulted in much clearer and contrasted endoscopic views. These advances have greatly minimized the drawbacks of 2D images. These advantages prompted us to develop a keyhole operation for tympanoplasty using TEES to remove cholesteatomas. Tympanoplasty for middle ear cholesteatomas is traditionally performed under an operation microscope. Because of the straight-line view offered by the microscope, a wide transcortical mastoidectomy is necessary (2). However, visualization of deep recesses in the middle ear is limited. Therefore, this conventional technique requires surgical exposure to visualize behind the obstructions and overhangs. Yet anatomic dead corners still remain such as the tympanic sinus (11). Surgical goals for cholesteatomas are to remove diseased tissue, to make a dry ‘‘safe’’ ear, to preserve normal anatomy, and to improve or preserve hearing. To accomplish these tasks, several microscopic surgical techniques for cholesteatomas have been developed since the 1950s when the microscope was first introduced into middle ear surgery. However, the recurrent cholesteatoma rate has been reported to be very high (12). In contrast, endoscopes offer several advantages over the microscope; a wide field of view, high magnification through a close approach to objects, and clear visualization of hidden structures such as the retrotympanum and supratubal recess (13,14). These advantages have made the Otology & Neurotology, Vol. 35, No. 1, 2014
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endoscope a useful surgical tool (15Y17). However, the endoscope was only used as an adjunct to conventional surgical techniques. Thomassin et al. (18) used a rigid endoscope as part of conventional surgical microscopy in middle ear surgery resulting in reduction of the cholesteatoma residue. Development of a CCD camera coupled with the rigid endoscope facilitated complete removal of the epidermal residue of the cholesteatomas using a special set of endoscopic surgical instruments (18Y21). However, despite these advances resulting in incorporation of the endoscope into microscopic surgery, repeatedly switching from the microscope to the endoscope during surgery is cumbersome and hinders a smooth procedure. Thus, surgeons worked on developing procedures that could be performed solely with the endoscope (22). Tarabichi reported successful results with TEES for limited attic cholesteatomas (1,2). After the introduction of the HD camera system, transcanal management of middle ear has become widely used. TEES thus gradually became the obvious choice for removing cholesteatomas because of its clear advantages including reduced dead corners and preservation of the mastoid mucosa. However, indications for TEES were limited to early cholesteatomas because transcanal atticotomy was mainly performed with curettes and/or Skeeter drills. We have thus been working to expand the indications for TEES to facilitate a smoother surgical experience for the surgeon and achieve better results for patients. A major step in this direction was performing retrograde mastoidectomy on demand via TEES using the Sonopet UBC. Usage of the UBC, which delivers bone cutting, irrigation, and suction simultaneously in a single handpiece overcomes problems associated with TEES such as one-handed surgery and limitation of bone cutting that have restricted its indications. The UBC has been used in neurosurgery (7), paranasal sinus surgery (8), maxillofacial surgery (9), and spinal surgery (10). The nonrotating design of the UBC makes its safe and suitable in a small surgical field like the ear canal. The UBC allows for minimal bone cutting and maximal preservation of the mucosa during endoscopic transcanal retrograde mastoidectomy on demand. The resulting opening was small enough to be covered with the tragal cartilage in all cases. We have therefore expanded the indications for TEES in cholesteatoma surgery to include cholesteatomas extending up to the antrum because of the use of the UBC. However, cases are excluded with inner ear fistula, wide exposure of dura, or infiltrative cholesteatoma. Our surgical results were good for the TEES with UBC procedure from the start. However, we have improved the presurgical evaluation procedure and have been able to expand the number of candidates (Table 2). The presurgical evaluation was initially conducted based only a CT scan, which leads to overestimation of the cholesteatoma in a number of cases. When an MRI was also performed as part of the presurgical evaluation, we were able to obtain more precise results, particularly with non-EPI-DW. However, surgeons need to be confident that the UBC is absolutely safe to be used within a structurally deli-
TABLE 2. Surgical procedures and anatomaic locations of cholesteatomas between January 2012 and December 2012
TEES Dual (TEES+MES) MES (CWD) Total
TA
M
Others
Total
23 0 0 23
13 4 18 35
0 0 1 1
36 4 19 59
cate area such as the middle ear, which is positioned in a neurologically sensitive location. Salami et al. (23) reported the usefulness and safety of another type of ultrasonic bone cutting system, Piezosurgery (Piezosurgery SRL, Genoa, Italy) in microscopic middle ear surgery. The Piezosurgery UBC is similar but not exactly the same as the Sonopet. Specifically, the Piezosurgery UBC has no suction function in the tip. They reported that no patients presented with postoperative worsening audiologic examinations such as pure-tone audiometry, TEOAE, DPOAE, and ABR. However, no reports were found in the literature regarding potential risks related to use of UBCs in the inner ear. We thus examined the effects of the UBC on the inner ear by measuring skull vibrations caused by the UBC (24). That study revealed that skull bone vibrations caused by the UBC compared favorably with the vibrations caused by conventional high-speed drills and thus confirmed that the UBC is sufficiently safe for use in the inner ear. The heat effect during the pressure of the tip of the UBC into the bone is also an important issue to be addressed. Adverse effects caused by heat production have not been reported in the literature. The increase in temperature caused by Sonopet UBC was reported to be minimal when used with a procedure which employs repeated single strokes across the surface with the tip removed from the surface after each stroke (25). However, bone cutting clearly requires adequate irrigation. Although not specifically related to safety, another important concern is operating time. Previous articles on neurosurgery and spinal surgery reported that the UBC requires more time for resections of large amounts of bone (26,27). However, we found that the operating time for TEES using the UBC was no longer than the time required for the conventional microscopic approach. The average operating time for the primary cases of acquired cholesteatomas with TEES was 247 T 91 minutes (n = 34), whereas the time required with the conventional microscopic approach for procedures conducted between 2008 and 2010 was 256 T 41 minutes (n = 44). These times are not significantly different. This good result for operating time is partly because the UBC is efficient in cutting the attic and partly because the retrograde mastoidectomy performed with the UBC requires much less bone cutting. The transcanal approach also cuts down dramatically on operating time because no retroauricular incisions are made, which subsequently need to be sutured. In conclusion, the transcanal endoscopic approach to the antrum using powered instruments proved to be less invasive and more functional. The UBC, a single handpiece
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EXTENSION OF INDICATIONS FOR TEES containing both a suction and irrigation system, is an appropriate cutting tool that enables the extension of indications for TEES. Acknowledgments: The authors thank Melinda Hull for valuable suggestions concerning English usage.
REFERENCES 1. Tarabichi M. Endoscopic management of acquired cholesteatoma. Am J Otol 1997;18:544Y9. 2. Tarabichi M. Endoscopic management of limited attic cholesteatoma. Laryngoscope 2004;114:1157Y62. 3. Marchioni D, Mattioli F, Alicandri-Ciufelli M, Presutti L. Endoscopic approach to tensor fold in patients with attic cholesteatoma. Acta Otolaryngol 2009;129:946Y54. 4. Migirov L, Shapira Y, Horowitz Z, Wolf M. Exclusive endoscopic ear surgery for acquired cholesteatoma: preliminary results. Otol Neurotol 2011;32:433Y6. 5. Ayache S. Cartilaginous myringoplasty: the endoscopic transcanal procedure. Eur Arch Otorhinolaryngol 2013;270:853Y60. 6. Tos M. Manual of Middle Ear Surgery. Vol 2: Mastoid Surgery and Reconstructive Procedures. New York, NY: Thieme Medical Publishers, 1995:258Y60. 7. Hadeishi H, Suzuki A, Yasui N, Satou Y. Anterior clinoidectomy and opening of the internal auditory canal using an ultrasonic bone curette. Neurosurgery 2003;52:867Y70; discussion 870Y1. 8. Pagella F, Giourgos G, Matti E, Colombo A, Carena P. Removal of a fronto-ethmoidal osteoma using the Sonopet omni ultrasonic bone curette: first impressions. Laryngoscope 2008;118:307Y9. 9. Ueki K, Nakagawa K, Marukawa K, Yamamoto E. Le Fort I osteotomy using an ultrasonic bone curette to fracture the pterygoid plates. J Craniomaxillofac Surg 2004;32:381Y6. 10. Nakagawa H, Kim SD, Mizuno J, Ohara Y, Ito K. Technical advantages of an ultrasonic bone curette in spinal surgery. J Neurosurg Spine 2005;2:431Y5. 11. Merchant SN, Nadol JB Jr. Schuknecht’s Pathology of the Ear. 3rd ed. Shelton, CT: PMPH-USA, 2010:56. 12. Stangerup SE, Drozdziewicz D, Tos M, Hougaard-Jensen A. Recurrence of attic cholesteatoma: different methods of estimating recurrence rates. Otolaryngol Head Neck Surg 2000;123:283Y7.
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13. Kakehata S, Futai K, Kuroda R, et al. Office-based endoscopic procedure for diagnosis in conductive hearing loss cases utilizing OtoScan laser-assisted myringotomy. Laryngoscope 2004;114:1285Y9. 14. Marchioni D, Mattioli F, Alicandri-Ciufelli M, Presutti L. Transcanal endoscopic approach to the sinus tympani: a clinical report. Otol Neurotol 2009;30:758Y65. 15. McKennan KX. Endoscopic ’second look’ mastoidoscopy to rule out residual epitympanic/mastoid cholesteatoma. Laryngoscope 1993;103:810Y4. 16. Rosenberg SI, Silverstein H, Hoffer M, Nichols M. Use of endoscopes for chronic ear surgery in children. Arch Otolaryngol Head Neck Surg 1995;121:870Y2. 17. Youssef TF, Poe DS. Endoscope-assisted second-stage tympanomastoidectomy. Laryngoscope 1997;107:1341Y4. 18. Thomassin JM, Korchia D, Doris JM. Endoscopic-guided otosurgery in the prevention of residual cholesteatomas. Laryngoscope 1993;103:939Y43. 19. Badr-El-Dine M. Value of ear endoscopy in cholesteatoma surgery. Otol Neurotol 2002;23:631Y5. 20. El-Meselaty K, Badr-El-Dine M, Mandour M, Mourad M, Darweesh R. Endoscope affects decision making in cholesteatoma surgery. Otolaryngol Head Neck Surg 2003;129:490Y6. 21. Presutti L, Marchioni D, Mattioli F, Villari D, Alicandri-Ciufelli M. Endoscopic management of acquired cholesteatoma: our experience. J Otolaryngol Head Neck Surg 2008;37:481Y7. 22. Kakehata S, Futai K, Sasaki A, et al. Endoscopic transtympanic tympanoplasty in the treatment of conductive hearing loss: Early results. Otol Neurotol 2006;27:14Y9. 23. Salami A, Dellepiane M, Ralli G, Crippa B, Mora R. Effects of Piezosurgery on the cochlear outer hair cells. Acta Otolaryngol 2009;129:497Y500. 24. Ito T, Mochizuki H, Watanabe T, et al. Intraoperative measurement of skull bone vibration during mastoidectomy using an ultrasonic bone curette. Otol Neurotol (in press). 25. Kobayashi N, Hadeishi H, Suzuki A. Thermal analysis of bone removal with Ultrasound Bone Curette. 74th Annual Meeting of the American Association of Neurological Surgeons, San Francisco, 2006.4. 26. Nakase H, Matsuda R, Shin Y, et al. The use of ultrasonic bone curettes in spinal surgery. Acta Neurochir (Wien) 2006;148:207Y12. 27. Chang HS, Joko M, Song JS, et al. Ultrasonic bone curettage for optic canal unroofing and anterior clinoidectomy. J Neurosurg 2006;104:621Y4.
Otology & Neurotology, Vol. 35, No. 1, 2014
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Extension of Indications for Transcanal Endoscopic Ear Surgery Using an Ultrasonic Bone Curette for Cholesteatomas Seiji Kakehata, Tomoo Watanabe, Tsukasa Ito, Toshinori Kubota, and Takatoshi Furukawa Department of Otolaryngology, Head and Neck Surgery, Yamagata University Faculty of Medicine, Yamagata, Japan
UBC prevents injury to the tympanomeatal flap and other soft tissue, which may result with standard drills. Transcanal endoscopic retrograde mastoidectomy on demand was performed to access the pathologies in the attic and antrum. Results: A minimum attico-antrotomy was performed using the UBC, removing only the bony tissue necessary to visualize the pathology. The cholesteatoma was completely removed from the antral mucosa under clear endoscopic visualization in 13 of 14 cases. After removal of the cholesteatoma, the canal wall was reconstructed using cartilage taken from the tragus. This procedure resulted in greater mastoid preservation. Conclusion: The transcanal endoscopic approach to the antrum using the UBC proved to be less invasive and more functional. The UBC contains both a suction and irrigation system in a single handpiece, and this UBC is an appropriate cutting tool that extends the indications for TEES. Key Words: CholesteatomaVLess invasive surgeryVRetrograde mastoidectomy on demandV Transcanal endoscopic ear surgeryVUltrasonic bone curette.
Background: One-handed endoscopic procedures have, up until now, limited the indications for transcanal endoscopic ear surgery (TEES) in cholesteatoma surgery. However, the development of electrically powered instruments has opened the door to such one-handed endoscopic procedures in restricted surgical spaces. Objective: We examined the feasibility of using one such powered instrument, the ultrasonic bone curette (UBC) in TEES for cholesteatoma surgery. The UBC offers several advantages, including nonrotational motion and the combination of both suction and irrigation in a single handpiece. Study Design: A prospective case series. Setting: Tertiary referral center. Patients: TEES was performed on 43 cases of primary cholesteatoma between September 2011 and December 2012, including 14 cases extending to the antrum. Intervention: Zero-, 30-, or 70-degree angled rigid endoscopes with an outer diameter of 2.7 mm (Karl Storz) were used together with a high-definition video system. A Sonopet UBC (Stryker) was used to cut bony tissue. The nonrotational motion of the
Otol Neurotol 35:101Y107, 2014.
Transcanal endoscopic ear surgery (TEES) is a keyhole procedure (1Y5). The combination of thin rigid otoendoscopes and a full high-definition (HD) camera system facilitates a less invasive transcanal approach to the middle ear with clear and high contrast views that overcome the drawbacks of the standard 2D views of endoscopy. The endoscope offers advantages such as a wide field of view, high magnification, and fewer anatomic dead corners, and these advantages make TEES a viable candidate for tympanoplasty. TEES overcomes the drawbacks of microscopic ear surgery (MES) such as wide bone cutting and inevita-
ble anatomical dead corners. However, standard drills are difficult to use for bone cutting in TEES because of the limited working space in the external auditory canal, which is surrounded by bone. The rotating bur of standard drills can also catch the meatal skin flap. Transcanal procedures have thus been performed mainly with curettes, and the use of such curettes has limited the indications of TEES to cholesteatomas within the tympanic cavity and the attic. We have started to treat cholesteatomas using a TEES procedure called endoscopic retrograde mastoidectomy on demand together with an ultrasonic bone curette (UBC). The endoscopic retrograde mastoidectomy on demand procedure allows us to move, anatomic section by anatomic section, through the ear canal and cut only the bone up to the location of the cholesteatoma. This less invasive approach is in stark contrast to the microscopic
Address correspondence and reprint requests to Seiji Kakehata, M.D., Ph.D., Department of Otolaryngology, Head and Neck Surgery, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata-shi, Yamagata, 990-9585, Japan; E-mail: [email protected] The authors disclose no conflicts of interest.
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FIG. 1. Ultrasonic bone curette, Sonopet UST-2001 (Stryker). A, Sonopet 25MA Universal Handpiece. B, The small H201 LT tip uses longitudinal-torsional compound vibrations. C, The UBC has a suction apparatus in the back of the tip.
transcortical mastoidectomy (6), which requires substantial removal of cortical bone and mucosa in the mastoid, regardless of the location of the cholesteatoma. These superior results are due, in large part, to the use of the UBC, which contains a suction-irrigation system in a single handpiece. The nonrotational motion of the UBC prevents damage to the tympanomeatal flap or other soft tissue, which a standard drill can cause (7Y10). Our TEES procedure is described herein, focusing particularly on the incorporation of the UBC into this procedure. We further show how TEES, together with the UBC, can be used to successfully treat cholesteatomas with potentially better results than conventional procedures.
Intervention Cholesteatoma surgery was performed in the ear canal completely under endoscopic visualization using TEES. 0-, 30-,
METHODS Patients Ninety-six patients underwent tympanoplasty for middle ear cholesteatoma at our institute between September 2011 and December 2012. The patients were 42 female and 54 male subjects, ranging in age from 2 to 82 years, with a mean age of 44.2 years. Among these patients, 6 presented with congenital cholesteatomas and 90 with acquired cholesteatomas, including 69 primary cases. The cholesteatoma extended to the mastoid region in 38 cases. TEES was performed on 43 cases, including 14 cases extending to the antrum. Four cases extending up to the mastoid tip were treated with a dual approach, a canal wall up procedure where TEES is combined with transcortical mastoidectomy under microscopy. The study protocol was approved in advance by the ethics committee of Yamagata University Faculty of Medicine, Yamagata, Japan.
FIG. 2. A photograph (A) and a schema (B) show the TEES procedure with the Sonopet UBC.
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FIG. 3. The TEES surgical procedure (right ear). A, Surgical view with a 0-degree angled endoscope. B, Circumferential incision in the EAC. C, Elevation of the tympanomeatal flap. After checking the retrotympanum, the incudostapedial joint is cut. Note the clear view of the retrotympanum with a 0-degree angled endoscope.
or 70-degree angled rigid endoscopes with an outer diameter of 2.7 mm (Stroz, Germany) were used. Images were recorded through a full high-definition (HD) camera (Stroz, Germany), which was attached to the endoscope lens, and these images were displayed on a full HD monitor. Endoscopic transcanal retrograde mastoidectomy on demand was performed to access the pathologies in the attic and antrum.
This procedure allows for minimal removal of the bone and maximal preservation of the mucosa. A Sonopet UBC (Stryker, USA) (Fig. 1) was used to cut the bony tissue via a transcanal approach (Fig. 2). This device delivers bone cutting, irrigation, and suction simultaneously in a single handpiece, therefore making the UBC suitable for one-handed TEES. The handpiece is 130 mm in length from the tip to the angled section and 117 mm
FIG. 4. The TEES surgical procedure (continued). A, Retrograde mastoidectomy on demand with the UBC. B, A thin bony shelf is left inside. C, The bony shelf is removed with a high-speed curved bur. D, The matrix is elevated from the antrum to attic, leaving the mucosa intact using a double bent elevator. Otology & Neurotology, Vol. 35, No. 1, 2014
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in the grip section (Fig. 1A). The tip of the UBC is 1.0 1.9 3.0 mm in size and has both longitudinal and torsional (LT) movement at a frequency of 25 kHz with a maximum amplitude of 300 Km. LT oscillation allows bony tissue to be cut with no kicking or grabbing of the soft tissue. The oscillating tip is covered with a tip cover (Fig. 1B), and irrigation water flows between the tip and the cover. The water is aspirated from a suction hole on the back of the tip (Fig. 1C).
The cholesteatoma matrix from the antrum is completely removed with the matrix from the mesotympanum. After removal of the cholesteatoma, an anterior ventilation route is made to prevent cholesteatoma recurrence (Fig. 5A). Reconstruction of the ossicular chain and the bony canal wall are performed using cartilage with perichondrium harvested from the tragus (Fig. 5, B and C). The tympanomeatal flap is put back into place (Fig. 5D), and then, the EAC is packed with chitin sheets, Gelfoam sponges soaked in antibiotic eardrops, and Merocol sponges.
TEES Procedure TEES is performed under general anesthesia. A local anesthesia is administered to the bony ear canal to suppress possible bleeding and elevate the skin of the ear canal. A circumferential incision is made in the middle of the bony ear canal with a round knife (Fig. 3B). The tympanomeatal flap is lifted anteriorly, allowing a clear visualization of the tympanic cavity, including the retrotympanum (Fig. 3C). The matrix in the cavity, if present, is elevated under direct visualization. Retrograde mastoidectomy on demand is performed with the UBC starting with an atticotomy (Fig. 4, AYC). A thin bony shelf is left in the attic and antrum to protect the delicate structures until bone cutting is almost completed (Fig. 4B). A final step is to then remove this shelf with a hammer, chisels, and curettes and then polish the area with a high-speed curved bur (Fig. 4C). This procedure is performed until the edge of the cholesteatoma is visible. Once the edge is identified, the matrix is elevated from the antrum to attic, leaving the mucosa intact (Fig. 4D).
RESULTS TEES indications for cholesteatoma have been successfully expanded to cases extending up to the antrum. We selected the operative procedure presurgically based on these expanded indications for patients treated from September 2011 to December 2012. Our selection process was originally based solely on a CT evaluation, but the evaluation was revised in January 2012 to include both a CT and MRI evaluation, including EPI-DW or non-EPI-DW. This revised evaluation lead to better results, particularly in accurately estimating shadows in the mastoid, which had been overestimated in 4 early cases. Exclusion criteria are: inner ear fistula, wide exposure of the dura, and infiltrative cholesteatoma.
FIG. 5. The TEES surgical procedure (continued). Reconstruction of the ossicular chain and the bony canal wall. A, Making an anterior ventilation route. B, Insertion of the double cartilage with a dimple onto the stapes head. C, Covering the 8 5 mm defect of the EAC using cartilage with perichondrium. D, The tympanomeatal flap was put back into place. Otology & Neurotology, Vol. 35, No. 1, 2014
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EXTENSION OF INDICATIONS FOR TEES Primary Cases First-stage operations were performed in 69 of the 96 cholesteatoma cases. This group of 69 can be further divided into 30 cholesteatomas (43%), which were limited to within the tympanic cavity and/or attic while 38 (55.0%) extended to the mastoid region with 1 located in the petrous apex (Table 1). All 69 patients were presurgically evaluated for the appropriate surgical approach from among TEES, a dual TEES/MES procedure, or canal wall down (CWD). Twenty-six (86.7%) of 30 cholesteatomas up to the attic and 14 (37%) of 38 cholesteatomas extending up to the mastoid were classified as good candidates for TEES for a total of 40 cases. TEES was successfully performed in all 26 of the cholesteatomas up to the attic and 13 of 14 of the mastoid cholesteatomas. The surgical approach was switched during surgery for 1 case to a CWD procedure under microscopy because the infiltrative matrix of the cholesteatoma extended up to the mastoid tip, and new bone formations were found. Retrograde Mastoidectomy on Demand Retrograde mastoidectomy on demand was performed employing a minimum attico-antrotomy. This atticoantrotomy was performed using the UBC without difficulties in most of the 39 cases including when the cholesteatoma extended all the way to the mastoid region. The UBC greatly facilitates cutting of the bony tissue, which is blocking visualization of the diseased area including the cholesteatoma itself, effusions, and granulations. The necessary bony tissue is cut, and an opening not exceeding 10 mm in length is fashioned by the UBC. The cholesteatoma matrix can then be continuously elevated while leaving the mucosa intact. The matrix is removed, ideally in one piece, but occasionally in a small number of large pieces from the antrum to the attic using a double bent elevator and curved suction tubes. The surgical field is kept clear by stopping any hemorrhaging using neurosurgical sponges, Bemsheets, which are soaked in epinephrine. Effusions in the peripheral mastoid cells were suctioned with several types of bent suction tubes. Granulations were removed as much as possible with bent elevators and the suction tubes. The 30- or 70-degree angled endoscopes were used to confirm that no cholesteatoma residue remained in the mastoid. However, a number of issues need to be kept in mind and dealt with as necessary during surgery. First, the outer TABLE 1. Surgical procedures and anatomaic locations of cholesteatomas between September 2011 and December 2012
TEES Dual (TEES+MES) MES (CWD) Total
TA
M
Others
Total
26 0 4 30
13 4 21 38
0 0 1 1
39 4 26 69
CWD indicates canal wall down; M, mastoid; MES, microscopic ear surgery; TA, tympanic cavity and/or attic; TEES, transcanal endoscopic ear surgery.
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covering of the UBC may be too thick to allow access to the deepest areas such as the supratubal recess in patients with a narrow EAC. In addition, the amount of irrigation water and degree of suction needs to be carefully set to obtain a clear endoscopic view. Finally, the tympanomeatal flap can be caught up by the UBC suction, but this problem can be averted by placing a piece of sterile paper on the tympanomeatal flap creating a protective barrier. The ease of this surgery can be largely attributed to the preservation of a thin bony shelf within the ear canal to prevent unexpected injury to important structures such as the ossicles, facial nerve, and inner ear. Once the bone cutting is nearly completed, this shelf is removed with a hammer, chisels and/or curettes, and then smoothed with a high-speed curved diamond bur. Finally, the opening created by the UBC through which the cholesteatoma matrix was removed is repaired using cartilage from the tragus.
DISCUSSION The use of a powered instrument such as a UBC with TEES is reported herein for the first time in cholesteatoma surgery. TEES allows all aspects of surgery to be performed in the external and middle ear under endoscopy, and TEES is a less invasive surgical procedure with minimal pain, no auricular numbness, no auricular displacement, and reduced hospitalization. However, several drawbacks of TEES such as the 2D image, one-handed surgery, and limitations of bone cutting have impacted the adoption of this procedure. Advances in technology, specifically the development of a full HD camera system, have resulted in much clearer and contrasted endoscopic views. These advances have greatly minimized the drawbacks of 2D images. These advantages prompted us to develop a keyhole operation for tympanoplasty using TEES to remove cholesteatomas. Tympanoplasty for middle ear cholesteatomas is traditionally performed under an operation microscope. Because of the straight-line view offered by the microscope, a wide transcortical mastoidectomy is necessary (2). However, visualization of deep recesses in the middle ear is limited. Therefore, this conventional technique requires surgical exposure to visualize behind the obstructions and overhangs. Yet anatomic dead corners still remain such as the tympanic sinus (11). Surgical goals for cholesteatomas are to remove diseased tissue, to make a dry ‘‘safe’’ ear, to preserve normal anatomy, and to improve or preserve hearing. To accomplish these tasks, several microscopic surgical techniques for cholesteatomas have been developed since the 1950s when the microscope was first introduced into middle ear surgery. However, the recurrent cholesteatoma rate has been reported to be very high (12). In contrast, endoscopes offer several advantages over the microscope; a wide field of view, high magnification through a close approach to objects, and clear visualization of hidden structures such as the retrotympanum and supratubal recess (13,14). These advantages have made the Otology & Neurotology, Vol. 35, No. 1, 2014
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endoscope a useful surgical tool (15Y17). However, the endoscope was only used as an adjunct to conventional surgical techniques. Thomassin et al. (18) used a rigid endoscope as part of conventional surgical microscopy in middle ear surgery resulting in reduction of the cholesteatoma residue. Development of a CCD camera coupled with the rigid endoscope facilitated complete removal of the epidermal residue of the cholesteatomas using a special set of endoscopic surgical instruments (18Y21). However, despite these advances resulting in incorporation of the endoscope into microscopic surgery, repeatedly switching from the microscope to the endoscope during surgery is cumbersome and hinders a smooth procedure. Thus, surgeons worked on developing procedures that could be performed solely with the endoscope (22). Tarabichi reported successful results with TEES for limited attic cholesteatomas (1,2). After the introduction of the HD camera system, transcanal management of middle ear has become widely used. TEES thus gradually became the obvious choice for removing cholesteatomas because of its clear advantages including reduced dead corners and preservation of the mastoid mucosa. However, indications for TEES were limited to early cholesteatomas because transcanal atticotomy was mainly performed with curettes and/or Skeeter drills. We have thus been working to expand the indications for TEES to facilitate a smoother surgical experience for the surgeon and achieve better results for patients. A major step in this direction was performing retrograde mastoidectomy on demand via TEES using the Sonopet UBC. Usage of the UBC, which delivers bone cutting, irrigation, and suction simultaneously in a single handpiece overcomes problems associated with TEES such as one-handed surgery and limitation of bone cutting that have restricted its indications. The UBC has been used in neurosurgery (7), paranasal sinus surgery (8), maxillofacial surgery (9), and spinal surgery (10). The nonrotating design of the UBC makes its safe and suitable in a small surgical field like the ear canal. The UBC allows for minimal bone cutting and maximal preservation of the mucosa during endoscopic transcanal retrograde mastoidectomy on demand. The resulting opening was small enough to be covered with the tragal cartilage in all cases. We have therefore expanded the indications for TEES in cholesteatoma surgery to include cholesteatomas extending up to the antrum because of the use of the UBC. However, cases are excluded with inner ear fistula, wide exposure of dura, or infiltrative cholesteatoma. Our surgical results were good for the TEES with UBC procedure from the start. However, we have improved the presurgical evaluation procedure and have been able to expand the number of candidates (Table 2). The presurgical evaluation was initially conducted based only a CT scan, which leads to overestimation of the cholesteatoma in a number of cases. When an MRI was also performed as part of the presurgical evaluation, we were able to obtain more precise results, particularly with non-EPI-DW. However, surgeons need to be confident that the UBC is absolutely safe to be used within a structurally deli-
TABLE 2. Surgical procedures and anatomaic locations of cholesteatomas between January 2012 and December 2012
TEES Dual (TEES+MES) MES (CWD) Total
TA
M
Others
Total
23 0 0 23
13 4 18 35
0 0 1 1
36 4 19 59
cate area such as the middle ear, which is positioned in a neurologically sensitive location. Salami et al. (23) reported the usefulness and safety of another type of ultrasonic bone cutting system, Piezosurgery (Piezosurgery SRL, Genoa, Italy) in microscopic middle ear surgery. The Piezosurgery UBC is similar but not exactly the same as the Sonopet. Specifically, the Piezosurgery UBC has no suction function in the tip. They reported that no patients presented with postoperative worsening audiologic examinations such as pure-tone audiometry, TEOAE, DPOAE, and ABR. However, no reports were found in the literature regarding potential risks related to use of UBCs in the inner ear. We thus examined the effects of the UBC on the inner ear by measuring skull vibrations caused by the UBC (24). That study revealed that skull bone vibrations caused by the UBC compared favorably with the vibrations caused by conventional high-speed drills and thus confirmed that the UBC is sufficiently safe for use in the inner ear. The heat effect during the pressure of the tip of the UBC into the bone is also an important issue to be addressed. Adverse effects caused by heat production have not been reported in the literature. The increase in temperature caused by Sonopet UBC was reported to be minimal when used with a procedure which employs repeated single strokes across the surface with the tip removed from the surface after each stroke (25). However, bone cutting clearly requires adequate irrigation. Although not specifically related to safety, another important concern is operating time. Previous articles on neurosurgery and spinal surgery reported that the UBC requires more time for resections of large amounts of bone (26,27). However, we found that the operating time for TEES using the UBC was no longer than the time required for the conventional microscopic approach. The average operating time for the primary cases of acquired cholesteatomas with TEES was 247 T 91 minutes (n = 34), whereas the time required with the conventional microscopic approach for procedures conducted between 2008 and 2010 was 256 T 41 minutes (n = 44). These times are not significantly different. This good result for operating time is partly because the UBC is efficient in cutting the attic and partly because the retrograde mastoidectomy performed with the UBC requires much less bone cutting. The transcanal approach also cuts down dramatically on operating time because no retroauricular incisions are made, which subsequently need to be sutured. In conclusion, the transcanal endoscopic approach to the antrum using powered instruments proved to be less invasive and more functional. The UBC, a single handpiece
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EXTENSION OF INDICATIONS FOR TEES containing both a suction and irrigation system, is an appropriate cutting tool that enables the extension of indications for TEES. Acknowledgments: The authors thank Melinda Hull for valuable suggestions concerning English usage.
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