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Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study
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Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study H.-Y. Tan a,b,c,1 , J. Yang a,b,c,1 , Z.-Y. Wang a,b,c,1 , W.-D. Zhu a,b,c , Y.-C. Chai a,b,c , H. Jia a,b,c,∗ , H. Wu a,b,c,∗∗ a Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China b Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China c Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
a r t i c l e
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Keywords: Endoscopic surgery Integrated operation room Skull base Cerebellopontine angle
a b s t r a c t Objective: To examine the impact of integrated hybrid operating rooms for endoscope-assisted microsurgery using the presigmoid retrolabyrinthine (RL) approach, and to determine the value of simultaneous supervision of skull base endoscopic procedures by microscope. Material and methods: We retrospectively reviewed endoscope-assisted surgery using the RL approach at our institution between September 2013 and January 2017. The simultaneous supervision of endoscopic procedures by microscope was realized using the integrated hybrid system. Intra- or postoperative complications and surgical outcomes were analyzed. All patients were followed for at least 1 year. Results: In total, 32 patients were studied: 4 vestibular schwannomas, 5 cholesteatomas, 8 hemifacial spasms, 5 glossopharyngeal neuralgias, and 10 Ménière’s disease. In patients with vestibular schwannoma or cholesteatoma, complete removal was performed in all patients. In patients with Ménière’s disease, hemifacial spasm or glossopharyngeal neuralgia, satisfactory symptom relief was achieved in all patients. Two (6.3%) patients had hearing loss after surgery which did not recover. One (3.1%) patient with vestibular schwannoma had mild facial palsy (HB III) at 2 weeks after the operation and recovered to near normal facial nerve function (HB II) at 1 year after surgery. No permanent or transient dysfunction of the trigeminal nerve or the lower cranial nerves was observed during follow-up. No complications such as cerebrospinal fluid (CSF) leakage or meningitis were observed. Conclusion: The endoscope provided a clearer and larger view, which solved the limitations of surgery using the RL approach. Endoscopic surgery under simultaneous supervision by microscope was safe and efficient in hearing preservation as well as in preservation of facial nerve function. An integrated operation room provided better support and the ability to switch quickly between these various complex devices. © 2018 Published by Elsevier Masson SAS.
1. Introduction Surgery in the cerebellopontine angle (CPA) is very challenging due to the presence of a great variety of vital neurovascular structures. Important blood vessels and nerves lining the skull base region increase the risk of intra- and postoperative hemorrhage and postoperative neurotic dysfunction. Cushing called the CPA the
∗ Corresponding author. No. 639 Zhizaoju Road, 200011 Shanghai, China. ∗∗ Co-Corresponding author. E-mail addresses: huan jia [email protected] (H. Jia), [email protected] (H. Wu). 1 Tan Hao-Yue, Yang Jie, and Wang Zhao-Yan contributed equally to this article.
“bloody triangle”, comparing it with the fence corner at the Battle of the Gettysburg because of the significant hemorrhage which can occur during vestibular schwannoma surgery [1]. With the rapid development of microscopy and intraoperative facial nerve monitoring, otologists and neurosurgeons can achieve a satisfactory rate of preservation of facial nerve function; however, hearing preservation remains poor for most patients. In the hope of improving the rates of preservation of hearing and facial function, the presigmoid retrolabyrinthine (RL) approach was first described by Hitselberger and Pulec for vestibular neurectomy, and Darrouzet et al. reported its first application in vestibular schwannoma [2,3]. By skeletonizing the semicircular canals and sigmoid sinus, the CPA was directly accessed through Trautmann’s
https://doi.org/10.1016/j.anorl.2018.08.003 1879-7296/© 2018 Published by Elsevier Masson SAS.
Please cite this article in press as: Tan H-Y, et al. Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study. European Annals of Otorhinolaryngology, Head and Neck diseases (2018), https://doi.org/10.1016/j.anorl.2018.08.003
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triangle without removal of the labyrinthine complex and with minimal cerebellar retraction. However, the drawbacks of the RL approach were quite obvious. Bento et al. reported that, in 3 of 22 patients who underwent vestibular schwannoma removal through a RL approach, total removal could not be achieved due to the unreachable fundus of the internal acoustic canal (IAC) [3]. Darrouzet et al. stated that only two-thirds of the lateral wall of the IAC could be observed using the RL approach [4]. Limited operating space and unsatisfactory exposure of the IAC have prevented the RL approach from being adopted more widely. The use of endoscopes in skull base procedures provides a wider and clearer view of the CPA and IAC. Although not widely reported, a major impediment to the application of the endoscope in skull base surgery was its probable mechanical and thermal injury to surrounding structures, similar to middle ear endoscopic surgery [5]. As a result of the development of the hybrid operation room, such as the STORZ OR1TM suite, endoscopic imaging and microscopic imaging could be merged and displayed on the same screen which allowed endoscopic manipulations to be performed under simultaneous supervision by microscope. The aim of this retrospective, clinical pilot study was to present the outcomes of endoscope-assisted microsurgery using the RL approach within the integrated hybrid operation room, and discuss the convenience and value of simultaneous supervision by microscope while using the endoscope in skull base surgery.
2. Material and methods
2.2. Integrated hybrid operation room The KARL STORZ Advanced OR1TM Suites (KARL STORZ GmbH & Co. KG, Tuttlingen, Germany) or Stryker iSuite (Stryker Communications, Flower Mound, Texas, USA) constituted our integrated hybrid operation room. The main modules of the OR1TM Suites contained Advanced Image and Data Acquisition (AIDATM ), Storz Communication Bus (SCB) and Audio-Video system, and the Stryker iSuite contained similar modules. The OR1TM , as an example, its main function is intuitive control of the entire surgical environment. The SCB control system enables central control of devices, including image sources, ceiling lights, peripheral cameras and other KARL STORZ compatible devices. All these devices can be controlled from a central location within the sterile area. AIDATM provides convenient archiving of multiple high-quality image sources from any signal, such as endoscope and microscope. It is therefore easier and quicker to record still image, videos and audio files of HD quality and to create documentation. Images from different signals can be displayed on the same screen (QUAD view or PiP) or on separate screens. With this system that offers intelligent routing and imaging solutions, interaction is possible from any location within seconds, e.g. from operating room to operating room, to the senior doctor’s office, to the lecture hall or to any other external location. Theoretically, the medical equipment’s’ signal access to the OR1TM could include endoscope, microscope, anesthetic machine, PACS, surgical cameras and so on. 2.3. Endoscope-assisted microsurgery under simultaneous supervision by microscope
2.1. Patients Patients who underwent endoscope-assisted microsurgery using the RL approach within the integrated hybrid operation room of our institution between September 2013 and January 2017 were retrospectively reviewed. This study focused on the following surgery: • functional microsurgery of the CPA, such as vestibular neurectomy for Ménière’s disease, glossopharyngeal neurectomy for glossopharyngeal neuralgia, and microvascular decompression for hemifacial spasm; • surgical removal of benign CPA tumors, such as small vestibular schwannoma (intracanalicular or CPA diameter ≤ 15 mm) and cholesteatoma. Patients with less than 1 year of follow-up after surgery were excluded from the study. The clinical records and operation videos of these patients were collected. All of the surgeries were performed by the same medical team, in which all intracranial manipulation procedures were performed by one surgeon (HW). Hearing level was evaluated using the American Academy of Otolaryngology – Head and Neck Surgery (AAO–HNS) guidelines and staged in four classes [6]. Facial nerve function was clinically evaluated using the HouseBrackmann (HB) scale [7]. The pain intensity score was evaluated using the Barrow Neurological Institute (BNI) pain intensity score [8]. Control of vertigo was categorized into Class A–F using a numerical value according to the classification of Ménière’s disease recommended by AAO–HNS [9]. Other postoperative complications including trigeminal nerve and lower cranial neurologic damage, cerebrospinal fluid (CSF) leakage and intracranial infection were also analyzed. The symptom relief rates as well as postoperative complications were evaluated at 2 weeks and 1 year after surgery. Patients who had undergone tumor resection were followed by an annual MRI scan.
The RL approach was performed using a classic approach [4]. The semicircular canals, the facial nerve and the sigmoid sinus were thoroughly skeletonized under microscopic view. The mastoid bone was removed from the sinodural angle to the jugular bulb. The dura was opened by a “U”-shaped incision in the rear of the endolymphatic sac and presigmoid. Then the endoscope (size of 4 mm, length of 17 cm) was brought into use, and the focal length of microscope was adjusted to about 400 mm. The Advanced OR1TM Suite was set to display the endoscopic and microscopic images simultaneously on its mobile screen (Figs. 1 and 2). The microscopic view was the minor image and was adjusted to observe the relationship between the endoscope probe and its surrounding tissue. If necessary, 0◦ , 30◦ , or 70◦ angled endoscopes were substituted during surgery. The intracranial manipulations were almost all performed under endoscopic view until dura closure, apart from certain two-handed gestures which were performed under microscopic view. 2.4. Ethics This study was approved by the Human Subjects Committee of the Shanghai Ninth People’s Hospital affiliated to Shanghai Jiaotong University School of Medicine. 2.5. Statistical analysis Data are presented as mean ± standard deviation (SD) or % (n) for descriptive statistics. Fisher’s exact or the 2 test was used for nominal variables. All analyses were done using SPSS 20.0 for Windows (IBM Corp., Armonk, NY, USA). Two-sided P-values less than 0.05 were considered to be statistically significant. 3. Results In total, 32 patients were included in the study (15 males and 17 females), with a mean age at surgery of 41.8 ± 12.5 years (Table 1).
Please cite this article in press as: Tan H-Y, et al. Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study. European Annals of Otorhinolaryngology, Head and Neck diseases (2018), https://doi.org/10.1016/j.anorl.2018.08.003
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Fig. 1. The spatial relationship of microscope, endoscope and image-merged screen. The surgical field is always present in microscopic view, and the movement of the endoscope body can be well supervised under microscopic view. The one-handed endoscope-assisted gesture and two-handed gesture with microscope can be quickly switched when required.
Fig. 2. The merged image on the screen. The main image (endoscopic) shown in fullscreen view, and the minor image (microscopic) displayed in quarter screen view. The minor image can be moved to the upper or lower, left or right quadrant so as not to obscure the main image.
There were 4 vestibular schwannomas, 5 cholesteatomas, 8 hemifacial spasms, 5 glossopharyngeal neuralgias, and 10 Ménière’s disease. All patients had serviceable hearing (Class A or B according to the AAO–HNS Classification) and good facial nerve function (Grade HB I–II) before surgery. The mean follow-up period was 30.6 ± 12.8 months. The integrated hybrid system worked well in all cases, and no intraoperative complications occurred. The endoscope-assisted
manipulation did not interfere with the simultaneous supervision by microscope. In terms of surgical removal of benign CPA tumors, complete removal was performed in all 9 patients. Serviceable hearing was preserved in all patients at 2 weeks after tumor resection but one patient with vestibular schwannoma presented delayed hearing loss at 1 year after surgery (deteriorated to Class C). Good facial function was preserved in eight patients, but one patient with vestibular schwannoma had mild facial palsy (HB III) at 2 weeks after the operation and further recovered to near normal (HB II) at 1 year after surgery. No residual tumor or recurrence of disease was observed during their follow-up. In terms of functional CPA surgery, all patients with Ménière’s disease achieved complete or a substantial control (Class A and B) of vertigo attacks; six (75%) patients with hemifacial spasm obtained complete relief, and two (25%) presented partial relief; four (80%) patients with glossopharyngeal neuralgia had excellent pain resolution (BNI 1–2) and one (20%) had good pain resolution (BNI 3). Apart from one patient with vestibular neurectomy who presented hearing loss after surgery (Class C), serviceable hearing and good facial function were preserved in the other patients. No recurrence was observed during follow-up. No permanent or transient dysfunction of the other cranial nerves was observed during follow-up. No complications such as CSF leakage or meningitis were observed.
Table 1 Demographic characteristics.
Age (y) Sex Male Female Side Right Left Tumor Size (mm) Postoperative Serviceable hearing at 1 y (n) Postoperative good facial function at 1 y (n) Surgical Outcome
Vestibular Schwannoma (n = 4)
Cholesteatoma (n = 5)
Hemifacial. Spasm (n = 8)
Glossophrayngeal Neuralgia (n = 5)
Menière’s Disease (n = 10)
47 ± 12.0
44.0 ± 11.4
35 ± 11.8
33 ± 15.8
48 ± 7.9
2 2
3 2
5 3
1 4
4 6
1 3 11 ± 2.2 3/4 4/4 No residual or recurrence
1 4 31 ± 6.9 5/5 5/5 No residual or recurrence
3 5 / 5/5 5/5 6/8 complete relief
4 1 / 5/5 5/5 4/5 complete relief
6 4 / 9/10 10/10 10/10 substantial control or above
Please cite this article in press as: Tan H-Y, et al. Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study. European Annals of Otorhinolaryngology, Head and Neck diseases (2018), https://doi.org/10.1016/j.anorl.2018.08.003
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5. Conclusion
Fig. 3. Custom-made suction curette. When removing an intracranial tumor using a one-handed gesture, a curette with suction is useful, and can reduce the frequency of instrument substitution.
4. Discussion The RL approach can preserve the labyrinthine complex, minimize bone drilling, reduce cerebellar retraction, and reach the CPA by a short route. The major drawback of this approach is the limited view of the CPA and IAC, mostly brought about by anatomical reasons, such as sheltering by the posterior semicircular canal, high jugular bulb, or anterior sigmoid sinus. Recently, these disadvantages have largely been overcome with the application of the endoscope in otoneurologic surgery. Cahali et al. reported that the 70◦ endoscope could show the entire IAC in 67.5% of specimens [10]. On cadaveric heads, Muelleman et al. verified that the entire IAC could be exposed with all kinds of angled endoscopes while preserving the labyrinthine complex [11]. Thus, the application of endoscope could be expanded into other surgery in CPA, due to its closer and multi-angled image without excessive bone drilled. In our study, we noted that the fundus of the IAC could be observed using the 70◦ endoscope, and tumors in the IAC could be resected using a suction curette, which is a new self-designed instrument (ZL 2017 2 0354811.0, CN Patent, being marketizing). It was modified by a classic suction with a shape curette on its extremity (Fig. 3). Surgeons should be well familiar with the anatomy of the CPA and they should have been trained in the use of various angled endoscopes. Although the endoscope provides a closer view of the surgical field and greatly expands the application of the RL approach, the lack of a lateral and posterior view due to the body of the endoscope makes it potentially dangerous. The important surrounding neurovascular structures are vulnerable to the sharp edges, shaft and hot lens of the endoscope, which could increase the risk of neurological dysfunction and hemorrhage [5]. Sanna and Caruso indicated that careful and accurate movement of the endoscope are important in the narrow “key-hole” dura incision under direct and close surveillance with a microscope [12]. The integrated hybrid operation room system was designed for optimally using the increasingly complex technologies in existing surgical workspaces. Merging of images from multiple sources is its main advantage. With the simultaneous supervision by microscope, endoscope movement and placement is safer, and the presence of the microscope did not disturb these surgical manipulations. In this series, no intra- or postoperative complications occurred. No tumor recurrence or residual disease was identified during follow-up and a satisfactory relief rate was achieved for functional microsurgery of the CPA. Postoperative hearing loss, which is uncommon, might be provoked by the loss of blood supply to the IAC due to surgery [13,14]. Because of one-handed manipulation with the endoscope, custom-made instruments are very helpful such as suction curettes for tumor removal. However, these manipulations are also challenging for some complex gestures, especially with blood-stained vision or the presence of hemorrhaging in the surgical field, so onehanded manipulations should not be performed forcefully so as to minimize accidental injury to important surrounding structures. A quick transition between endoscopic usage and microscopic usage is valuable and necessary, and the integrated system showed its convenience in this regard.
Endoscope-assisted microsurgery using a presigmoid retrolabyrinthine approach can provide direct access to the cerebellopontine angle along with preservation of the labyrinthine complex, leading to hearing preservation and minimal cerebellar retraction. Simultaneous supervision with a microscope improved the safety of endoscope use. An integrated operation room provided better support and quick transition between these various complex devices. Funding This work was supported by the Shanghai Scientific and Technological Innovation Action Plan under Project No 17441903600 hosted by JH, the Shanghai Scientific and Technological Innovation Action Plan under Project No 17441902800 hosted by CYC, the National Natural Science Foundation of China under Grant No. 81670919 hosted by WZY, Grant No. 81600815 hosted by CYC and Grant No. 81570906 hosted by WH, and Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases under Project No 14DZ2260300 hosted by WH. Disclosure of interest The authors declare that they have no competing interest. References [1] Ramsden RT. The bloody angle: 100 years of acoustic neuroma surgery. J R Soc Med 1995;88:464–8. [2] Hitselberger WE, Pulec JL. Trigeminal nerve (posterior root) retrolabyrinthine selective section. Operative procedure for intractable pain. Arch Otolaryngol 1972;96:412–5. [3] Bento RF, De Brito RV, Sanchez TG, Miniti A. The transmastoid retrolabyrinthine approach in vestibular schwannoma surgery. Otolaryngol Head Neck Surg 2002;127:437–41, http://dx.doi.org/10.1067/mhn.2002.129824. [4] Darrouzet V, Guerin J, Aouad N, Dutkiewicz J, Blayney AW, Bebear JP. The widened retrolabyrinthine approach: a new concept in acoustic neuroma surgery. J Neurosurg 1997;86:812–21, http://dx.doi.org/10.3171/jns.1997.86.5.0812. [5] Mitchell S, Coulson C. Endoscopic ear surgery: a hot topic? J Laryngol Otol 2017;131:117–22, http://dx.doi.org/10.1017/S0022215116009828. [6] Committee on Hearing and Equilibrium Guidelines for the Evaluation of Hearing Preservation in Acoustic Neuroma (Vestibular Schwannoma): Committee on Hearing and, Equilibrium. Otolaryngol Head Neck Surg 1995;113:179–80, http://dx.doi.org/10.1016/s0194-5998(95)70101-x. [7] House JW, Brackmann DE. Facial nerve grading system. Otolaryngol Head Neck Surg 1985;93:146–7, http://dx.doi.org/10.1177/019459988509300202. [8] Rogers CL, Shetter AG, Fiedler JA, Smith KA, Han PP, Speiser BL. Gamma knife radiosurgery for trigeminal neuralgia: the initial experience of The Barrow Neurological Institute. Int J Radiat Oncol Biol Phys 2000;47:1013–9. [9] Committee on Hearing and Equilibrium. Committee on Hearing and Equilibrium guidelines for the diagnosis and evaluation of therapy in Menière’s, disease. American Academy of Otolaryngology-Head and Neck Foundation Inc. Otolaryngol Head Neck Surg 1995;113:181–5, http://dx.doi.org/10.1016/S0194-5998(95)70102-8. [10] Cahali RB, Cahali MB, V B Neto R, Bento RF, Ribas GC. Endoscopia do meato acústico interno pelo acesso retrolabiríntico. Rev Bras Otorrinolaringol 2004;70:616–21, http://dx.doi.org/10.1590/S0034-72992004000500007. [11] Muelleman T, Shew M, Alvi S, Shah K, Staecker H, Chamoun R, et al. Endoscopically assisted drilling, exposure of the fundus through a presigmoid retrolabyrinthine approach: a cadaveric feasibility study. Otolaryngol Head Neck Surg 2018;158:155–7, http://dx.doi.org/10.1177/0194599817733665. [12] Sanna M, Caruso AMD. Atlas of acoustic neurinoma microsurgery. Stuttgart: Thieme; 2010. [13] Lü J, Wu H, Huang Q, Yang J, Li Y. Application of the endoscope assisting in retrosigmoid approach vestibular schwannoma resection. Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2009;23:1–4, http://dx.doi.org/10.3969/j.issn.1001-1781.2009.01.001. [14] Li Y, Wu H, Chen X, Wang W, Jia H, Xiang M, et al. Study on the effect of internal auditory artery vasospasm on hearing and its protection topically using vasodilator. J Audiol Speech Pathol 2006;6:436–8, http://dx.doi.org/10.3969/j.issn.1006-7299.2006.06.011.
Please cite this article in press as: Tan H-Y, et al. Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study. European Annals of Otorhinolaryngology, Head and Neck diseases (2018), https://doi.org/10.1016/j.anorl.2018.08.003
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ANORL-798; No. of Pages 4
European Annals of Otorhinolaryngology, Head and Neck diseases xxx (2018) xxxx
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Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study H.-Y. Tan a,b,c,1 , J. Yang a,b,c,1 , Z.-Y. Wang a,b,c,1 , W.-D. Zhu a,b,c , Y.-C. Chai a,b,c , H. Jia a,b,c,∗ , H. Wu a,b,c,∗∗ a Department of Otolaryngology Head and Neck Surgery, Shanghai Ninth People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China b Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai, China c Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
a r t i c l e
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Keywords: Endoscopic surgery Integrated operation room Skull base Cerebellopontine angle
a b s t r a c t Objective: To examine the impact of integrated hybrid operating rooms for endoscope-assisted microsurgery using the presigmoid retrolabyrinthine (RL) approach, and to determine the value of simultaneous supervision of skull base endoscopic procedures by microscope. Material and methods: We retrospectively reviewed endoscope-assisted surgery using the RL approach at our institution between September 2013 and January 2017. The simultaneous supervision of endoscopic procedures by microscope was realized using the integrated hybrid system. Intra- or postoperative complications and surgical outcomes were analyzed. All patients were followed for at least 1 year. Results: In total, 32 patients were studied: 4 vestibular schwannomas, 5 cholesteatomas, 8 hemifacial spasms, 5 glossopharyngeal neuralgias, and 10 Ménière’s disease. In patients with vestibular schwannoma or cholesteatoma, complete removal was performed in all patients. In patients with Ménière’s disease, hemifacial spasm or glossopharyngeal neuralgia, satisfactory symptom relief was achieved in all patients. Two (6.3%) patients had hearing loss after surgery which did not recover. One (3.1%) patient with vestibular schwannoma had mild facial palsy (HB III) at 2 weeks after the operation and recovered to near normal facial nerve function (HB II) at 1 year after surgery. No permanent or transient dysfunction of the trigeminal nerve or the lower cranial nerves was observed during follow-up. No complications such as cerebrospinal fluid (CSF) leakage or meningitis were observed. Conclusion: The endoscope provided a clearer and larger view, which solved the limitations of surgery using the RL approach. Endoscopic surgery under simultaneous supervision by microscope was safe and efficient in hearing preservation as well as in preservation of facial nerve function. An integrated operation room provided better support and the ability to switch quickly between these various complex devices. © 2018 Published by Elsevier Masson SAS.
1. Introduction Surgery in the cerebellopontine angle (CPA) is very challenging due to the presence of a great variety of vital neurovascular structures. Important blood vessels and nerves lining the skull base region increase the risk of intra- and postoperative hemorrhage and postoperative neurotic dysfunction. Cushing called the CPA the
∗ Corresponding author. No. 639 Zhizaoju Road, 200011 Shanghai, China. ∗∗ Co-Corresponding author. E-mail addresses: huan jia [email protected] (H. Jia), [email protected] (H. Wu). 1 Tan Hao-Yue, Yang Jie, and Wang Zhao-Yan contributed equally to this article.
“bloody triangle”, comparing it with the fence corner at the Battle of the Gettysburg because of the significant hemorrhage which can occur during vestibular schwannoma surgery [1]. With the rapid development of microscopy and intraoperative facial nerve monitoring, otologists and neurosurgeons can achieve a satisfactory rate of preservation of facial nerve function; however, hearing preservation remains poor for most patients. In the hope of improving the rates of preservation of hearing and facial function, the presigmoid retrolabyrinthine (RL) approach was first described by Hitselberger and Pulec for vestibular neurectomy, and Darrouzet et al. reported its first application in vestibular schwannoma [2,3]. By skeletonizing the semicircular canals and sigmoid sinus, the CPA was directly accessed through Trautmann’s
https://doi.org/10.1016/j.anorl.2018.08.003 1879-7296/© 2018 Published by Elsevier Masson SAS.
Please cite this article in press as: Tan H-Y, et al. Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study. European Annals of Otorhinolaryngology, Head and Neck diseases (2018), https://doi.org/10.1016/j.anorl.2018.08.003
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triangle without removal of the labyrinthine complex and with minimal cerebellar retraction. However, the drawbacks of the RL approach were quite obvious. Bento et al. reported that, in 3 of 22 patients who underwent vestibular schwannoma removal through a RL approach, total removal could not be achieved due to the unreachable fundus of the internal acoustic canal (IAC) [3]. Darrouzet et al. stated that only two-thirds of the lateral wall of the IAC could be observed using the RL approach [4]. Limited operating space and unsatisfactory exposure of the IAC have prevented the RL approach from being adopted more widely. The use of endoscopes in skull base procedures provides a wider and clearer view of the CPA and IAC. Although not widely reported, a major impediment to the application of the endoscope in skull base surgery was its probable mechanical and thermal injury to surrounding structures, similar to middle ear endoscopic surgery [5]. As a result of the development of the hybrid operation room, such as the STORZ OR1TM suite, endoscopic imaging and microscopic imaging could be merged and displayed on the same screen which allowed endoscopic manipulations to be performed under simultaneous supervision by microscope. The aim of this retrospective, clinical pilot study was to present the outcomes of endoscope-assisted microsurgery using the RL approach within the integrated hybrid operation room, and discuss the convenience and value of simultaneous supervision by microscope while using the endoscope in skull base surgery.
2. Material and methods
2.2. Integrated hybrid operation room The KARL STORZ Advanced OR1TM Suites (KARL STORZ GmbH & Co. KG, Tuttlingen, Germany) or Stryker iSuite (Stryker Communications, Flower Mound, Texas, USA) constituted our integrated hybrid operation room. The main modules of the OR1TM Suites contained Advanced Image and Data Acquisition (AIDATM ), Storz Communication Bus (SCB) and Audio-Video system, and the Stryker iSuite contained similar modules. The OR1TM , as an example, its main function is intuitive control of the entire surgical environment. The SCB control system enables central control of devices, including image sources, ceiling lights, peripheral cameras and other KARL STORZ compatible devices. All these devices can be controlled from a central location within the sterile area. AIDATM provides convenient archiving of multiple high-quality image sources from any signal, such as endoscope and microscope. It is therefore easier and quicker to record still image, videos and audio files of HD quality and to create documentation. Images from different signals can be displayed on the same screen (QUAD view or PiP) or on separate screens. With this system that offers intelligent routing and imaging solutions, interaction is possible from any location within seconds, e.g. from operating room to operating room, to the senior doctor’s office, to the lecture hall or to any other external location. Theoretically, the medical equipment’s’ signal access to the OR1TM could include endoscope, microscope, anesthetic machine, PACS, surgical cameras and so on. 2.3. Endoscope-assisted microsurgery under simultaneous supervision by microscope
2.1. Patients Patients who underwent endoscope-assisted microsurgery using the RL approach within the integrated hybrid operation room of our institution between September 2013 and January 2017 were retrospectively reviewed. This study focused on the following surgery: • functional microsurgery of the CPA, such as vestibular neurectomy for Ménière’s disease, glossopharyngeal neurectomy for glossopharyngeal neuralgia, and microvascular decompression for hemifacial spasm; • surgical removal of benign CPA tumors, such as small vestibular schwannoma (intracanalicular or CPA diameter ≤ 15 mm) and cholesteatoma. Patients with less than 1 year of follow-up after surgery were excluded from the study. The clinical records and operation videos of these patients were collected. All of the surgeries were performed by the same medical team, in which all intracranial manipulation procedures were performed by one surgeon (HW). Hearing level was evaluated using the American Academy of Otolaryngology – Head and Neck Surgery (AAO–HNS) guidelines and staged in four classes [6]. Facial nerve function was clinically evaluated using the HouseBrackmann (HB) scale [7]. The pain intensity score was evaluated using the Barrow Neurological Institute (BNI) pain intensity score [8]. Control of vertigo was categorized into Class A–F using a numerical value according to the classification of Ménière’s disease recommended by AAO–HNS [9]. Other postoperative complications including trigeminal nerve and lower cranial neurologic damage, cerebrospinal fluid (CSF) leakage and intracranial infection were also analyzed. The symptom relief rates as well as postoperative complications were evaluated at 2 weeks and 1 year after surgery. Patients who had undergone tumor resection were followed by an annual MRI scan.
The RL approach was performed using a classic approach [4]. The semicircular canals, the facial nerve and the sigmoid sinus were thoroughly skeletonized under microscopic view. The mastoid bone was removed from the sinodural angle to the jugular bulb. The dura was opened by a “U”-shaped incision in the rear of the endolymphatic sac and presigmoid. Then the endoscope (size of 4 mm, length of 17 cm) was brought into use, and the focal length of microscope was adjusted to about 400 mm. The Advanced OR1TM Suite was set to display the endoscopic and microscopic images simultaneously on its mobile screen (Figs. 1 and 2). The microscopic view was the minor image and was adjusted to observe the relationship between the endoscope probe and its surrounding tissue. If necessary, 0◦ , 30◦ , or 70◦ angled endoscopes were substituted during surgery. The intracranial manipulations were almost all performed under endoscopic view until dura closure, apart from certain two-handed gestures which were performed under microscopic view. 2.4. Ethics This study was approved by the Human Subjects Committee of the Shanghai Ninth People’s Hospital affiliated to Shanghai Jiaotong University School of Medicine. 2.5. Statistical analysis Data are presented as mean ± standard deviation (SD) or % (n) for descriptive statistics. Fisher’s exact or the 2 test was used for nominal variables. All analyses were done using SPSS 20.0 for Windows (IBM Corp., Armonk, NY, USA). Two-sided P-values less than 0.05 were considered to be statistically significant. 3. Results In total, 32 patients were included in the study (15 males and 17 females), with a mean age at surgery of 41.8 ± 12.5 years (Table 1).
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Fig. 1. The spatial relationship of microscope, endoscope and image-merged screen. The surgical field is always present in microscopic view, and the movement of the endoscope body can be well supervised under microscopic view. The one-handed endoscope-assisted gesture and two-handed gesture with microscope can be quickly switched when required.
Fig. 2. The merged image on the screen. The main image (endoscopic) shown in fullscreen view, and the minor image (microscopic) displayed in quarter screen view. The minor image can be moved to the upper or lower, left or right quadrant so as not to obscure the main image.
There were 4 vestibular schwannomas, 5 cholesteatomas, 8 hemifacial spasms, 5 glossopharyngeal neuralgias, and 10 Ménière’s disease. All patients had serviceable hearing (Class A or B according to the AAO–HNS Classification) and good facial nerve function (Grade HB I–II) before surgery. The mean follow-up period was 30.6 ± 12.8 months. The integrated hybrid system worked well in all cases, and no intraoperative complications occurred. The endoscope-assisted
manipulation did not interfere with the simultaneous supervision by microscope. In terms of surgical removal of benign CPA tumors, complete removal was performed in all 9 patients. Serviceable hearing was preserved in all patients at 2 weeks after tumor resection but one patient with vestibular schwannoma presented delayed hearing loss at 1 year after surgery (deteriorated to Class C). Good facial function was preserved in eight patients, but one patient with vestibular schwannoma had mild facial palsy (HB III) at 2 weeks after the operation and further recovered to near normal (HB II) at 1 year after surgery. No residual tumor or recurrence of disease was observed during their follow-up. In terms of functional CPA surgery, all patients with Ménière’s disease achieved complete or a substantial control (Class A and B) of vertigo attacks; six (75%) patients with hemifacial spasm obtained complete relief, and two (25%) presented partial relief; four (80%) patients with glossopharyngeal neuralgia had excellent pain resolution (BNI 1–2) and one (20%) had good pain resolution (BNI 3). Apart from one patient with vestibular neurectomy who presented hearing loss after surgery (Class C), serviceable hearing and good facial function were preserved in the other patients. No recurrence was observed during follow-up. No permanent or transient dysfunction of the other cranial nerves was observed during follow-up. No complications such as CSF leakage or meningitis were observed.
Table 1 Demographic characteristics.
Age (y) Sex Male Female Side Right Left Tumor Size (mm) Postoperative Serviceable hearing at 1 y (n) Postoperative good facial function at 1 y (n) Surgical Outcome
Vestibular Schwannoma (n = 4)
Cholesteatoma (n = 5)
Hemifacial. Spasm (n = 8)
Glossophrayngeal Neuralgia (n = 5)
Menière’s Disease (n = 10)
47 ± 12.0
44.0 ± 11.4
35 ± 11.8
33 ± 15.8
48 ± 7.9
2 2
3 2
5 3
1 4
4 6
1 3 11 ± 2.2 3/4 4/4 No residual or recurrence
1 4 31 ± 6.9 5/5 5/5 No residual or recurrence
3 5 / 5/5 5/5 6/8 complete relief
4 1 / 5/5 5/5 4/5 complete relief
6 4 / 9/10 10/10 10/10 substantial control or above
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5. Conclusion
Fig. 3. Custom-made suction curette. When removing an intracranial tumor using a one-handed gesture, a curette with suction is useful, and can reduce the frequency of instrument substitution.
4. Discussion The RL approach can preserve the labyrinthine complex, minimize bone drilling, reduce cerebellar retraction, and reach the CPA by a short route. The major drawback of this approach is the limited view of the CPA and IAC, mostly brought about by anatomical reasons, such as sheltering by the posterior semicircular canal, high jugular bulb, or anterior sigmoid sinus. Recently, these disadvantages have largely been overcome with the application of the endoscope in otoneurologic surgery. Cahali et al. reported that the 70◦ endoscope could show the entire IAC in 67.5% of specimens [10]. On cadaveric heads, Muelleman et al. verified that the entire IAC could be exposed with all kinds of angled endoscopes while preserving the labyrinthine complex [11]. Thus, the application of endoscope could be expanded into other surgery in CPA, due to its closer and multi-angled image without excessive bone drilled. In our study, we noted that the fundus of the IAC could be observed using the 70◦ endoscope, and tumors in the IAC could be resected using a suction curette, which is a new self-designed instrument (ZL 2017 2 0354811.0, CN Patent, being marketizing). It was modified by a classic suction with a shape curette on its extremity (Fig. 3). Surgeons should be well familiar with the anatomy of the CPA and they should have been trained in the use of various angled endoscopes. Although the endoscope provides a closer view of the surgical field and greatly expands the application of the RL approach, the lack of a lateral and posterior view due to the body of the endoscope makes it potentially dangerous. The important surrounding neurovascular structures are vulnerable to the sharp edges, shaft and hot lens of the endoscope, which could increase the risk of neurological dysfunction and hemorrhage [5]. Sanna and Caruso indicated that careful and accurate movement of the endoscope are important in the narrow “key-hole” dura incision under direct and close surveillance with a microscope [12]. The integrated hybrid operation room system was designed for optimally using the increasingly complex technologies in existing surgical workspaces. Merging of images from multiple sources is its main advantage. With the simultaneous supervision by microscope, endoscope movement and placement is safer, and the presence of the microscope did not disturb these surgical manipulations. In this series, no intra- or postoperative complications occurred. No tumor recurrence or residual disease was identified during follow-up and a satisfactory relief rate was achieved for functional microsurgery of the CPA. Postoperative hearing loss, which is uncommon, might be provoked by the loss of blood supply to the IAC due to surgery [13,14]. Because of one-handed manipulation with the endoscope, custom-made instruments are very helpful such as suction curettes for tumor removal. However, these manipulations are also challenging for some complex gestures, especially with blood-stained vision or the presence of hemorrhaging in the surgical field, so onehanded manipulations should not be performed forcefully so as to minimize accidental injury to important surrounding structures. A quick transition between endoscopic usage and microscopic usage is valuable and necessary, and the integrated system showed its convenience in this regard.
Endoscope-assisted microsurgery using a presigmoid retrolabyrinthine approach can provide direct access to the cerebellopontine angle along with preservation of the labyrinthine complex, leading to hearing preservation and minimal cerebellar retraction. Simultaneous supervision with a microscope improved the safety of endoscope use. An integrated operation room provided better support and quick transition between these various complex devices. Funding This work was supported by the Shanghai Scientific and Technological Innovation Action Plan under Project No 17441903600 hosted by JH, the Shanghai Scientific and Technological Innovation Action Plan under Project No 17441902800 hosted by CYC, the National Natural Science Foundation of China under Grant No. 81670919 hosted by WZY, Grant No. 81600815 hosted by CYC and Grant No. 81570906 hosted by WH, and Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases under Project No 14DZ2260300 hosted by WH. Disclosure of interest The authors declare that they have no competing interest. References [1] Ramsden RT. The bloody angle: 100 years of acoustic neuroma surgery. J R Soc Med 1995;88:464–8. [2] Hitselberger WE, Pulec JL. Trigeminal nerve (posterior root) retrolabyrinthine selective section. Operative procedure for intractable pain. Arch Otolaryngol 1972;96:412–5. [3] Bento RF, De Brito RV, Sanchez TG, Miniti A. The transmastoid retrolabyrinthine approach in vestibular schwannoma surgery. Otolaryngol Head Neck Surg 2002;127:437–41, http://dx.doi.org/10.1067/mhn.2002.129824. [4] Darrouzet V, Guerin J, Aouad N, Dutkiewicz J, Blayney AW, Bebear JP. The widened retrolabyrinthine approach: a new concept in acoustic neuroma surgery. J Neurosurg 1997;86:812–21, http://dx.doi.org/10.3171/jns.1997.86.5.0812. [5] Mitchell S, Coulson C. Endoscopic ear surgery: a hot topic? J Laryngol Otol 2017;131:117–22, http://dx.doi.org/10.1017/S0022215116009828. [6] Committee on Hearing and Equilibrium Guidelines for the Evaluation of Hearing Preservation in Acoustic Neuroma (Vestibular Schwannoma): Committee on Hearing and, Equilibrium. Otolaryngol Head Neck Surg 1995;113:179–80, http://dx.doi.org/10.1016/s0194-5998(95)70101-x. [7] House JW, Brackmann DE. Facial nerve grading system. Otolaryngol Head Neck Surg 1985;93:146–7, http://dx.doi.org/10.1177/019459988509300202. [8] Rogers CL, Shetter AG, Fiedler JA, Smith KA, Han PP, Speiser BL. Gamma knife radiosurgery for trigeminal neuralgia: the initial experience of The Barrow Neurological Institute. Int J Radiat Oncol Biol Phys 2000;47:1013–9. [9] Committee on Hearing and Equilibrium. Committee on Hearing and Equilibrium guidelines for the diagnosis and evaluation of therapy in Menière’s, disease. American Academy of Otolaryngology-Head and Neck Foundation Inc. Otolaryngol Head Neck Surg 1995;113:181–5, http://dx.doi.org/10.1016/S0194-5998(95)70102-8. [10] Cahali RB, Cahali MB, V B Neto R, Bento RF, Ribas GC. Endoscopia do meato acústico interno pelo acesso retrolabiríntico. Rev Bras Otorrinolaringol 2004;70:616–21, http://dx.doi.org/10.1590/S0034-72992004000500007. [11] Muelleman T, Shew M, Alvi S, Shah K, Staecker H, Chamoun R, et al. Endoscopically assisted drilling, exposure of the fundus through a presigmoid retrolabyrinthine approach: a cadaveric feasibility study. Otolaryngol Head Neck Surg 2018;158:155–7, http://dx.doi.org/10.1177/0194599817733665. [12] Sanna M, Caruso AMD. Atlas of acoustic neurinoma microsurgery. Stuttgart: Thieme; 2010. [13] Lü J, Wu H, Huang Q, Yang J, Li Y. Application of the endoscope assisting in retrosigmoid approach vestibular schwannoma resection. Lin Chung Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2009;23:1–4, http://dx.doi.org/10.3969/j.issn.1001-1781.2009.01.001. [14] Li Y, Wu H, Chen X, Wang W, Jia H, Xiang M, et al. Study on the effect of internal auditory artery vasospasm on hearing and its protection topically using vasodilator. J Audiol Speech Pathol 2006;6:436–8, http://dx.doi.org/10.3969/j.issn.1006-7299.2006.06.011.
Please cite this article in press as: Tan H-Y, et al. Simultaneous supervision by microscope of endoscope-assisted microsurgery via presigmoid retrolabyrinthine approach: A pilot study. European Annals of Otorhinolaryngology, Head and Neck diseases (2018), https://doi.org/10.1016/j.anorl.2018.08.003