Image-guided sinus surgery: current concepts and technology

Image-guided surgery (IGS) has gained considerable acceptance in rhinologic surgery. Principles of registration paradigms and registration error serve to define certain intrinsic limitations of this technology. Real-world experiences have further elucidated other concepts that may guide the appropriate use of IGS. With such knowledge, the rhinologic surgeon may incorporate IGS into a wide range of procedures.     

Image-guided transnasal endoscopic surgery of the paranasal sinuses and anterior skull base

Image-guided surgery represents a new technology with applicability to patients undergoing functional endoscopic sinus surgery for medically refractory rhinosinusitis. It also shows promise in helping to safely expand minimally invasive transnasal endoscopic techniques for nonrhinosinusitis diagnoses of the paranasal sinuses, orbits, and anterior skull base. This report discusses the application of the InstaTrak, a commercially available image-guided surgical navigation system, in 109 consecutive operations. The device was useful for localization to within less than 3 mm in 106 (98%) cases. In the remaining three (2%) surgeries where the perceived accuracy was not within 3 mm, the device was not used. The acquisition of radiographic data, operating room set-up, intraoperative localization and complications, and indications for surgical navigation will be discussed.     

Image-guided sinus surgery: practical considerations

The availability and use of image-guidance systems for sinus surgery will probably continue to increase in the years ahead. Surgeons who use this technology must do so with an appreciation of its potential benefits, as well as its possible pitfalls.     

Image-guided surgery of the anterior skull base

Minimally invasive surgical procedures have revolutionized surgery of the paranasal sinuses. The endonasal procedure has become standard practice due to a better understanding of pathological physiology. However, malformations, previous operations and bleeding can interfere greatly with intraoperative orientation. Together with microscopy and endoscopy, image-guided surgery has the potential to be of significant assistance to the surgeon. We evaluated the electromagnetic navigation system InstaTrak 2000 (Visualization Technologies Inc., Lawrence, MA) in 168 patients with various disorders of the paranasal sinuses who underwent endonasal surgery. The system consists of a headset attached to an electronic transmitter which is fitted on the dorsum of the nose and in the external auditory canal. With the aid of low-frequency magnetic fields the position of the instrument equipped with an electromagnetic receiver is calculated on the basis of the reaction of ferromagnetic components in the magnetic field; the location is displayed in orthogonal sections on a high resolution screen. The intraoperative accuracy of the system was estimated to be 1.2-2.8 mm. The preparation time amounted to < 10 min. No system failures were observed. The InstaTrak 2000 navigation system is only suitable for endonasal surgery. The placement of the electromagnetic transmitter and receiver allows flexible head positioning through the use of a headset. This system is a valuable aid for the surgeon under anatomically complex conditions. The technology also lends itself well to training purposes, as visualization in different sectional planes augments the understanding of anatomy and pathological anatomy.     

Medical applications of electronic nose technology: review of current status.

Electronic noses, or artificial sensors of odorants. have been developed over the last ten years to perform a variety of identification tasks in various industries. This powerful technology is only beginning to be introduced in the field of medicine, but is promising in its potential to assist in diagnosis. This article reviews electronic nose technology and some initial investigations of potential applicability of the technology in the field of medicine.     

Image-guided endoscopic sinus surgery: a comparison of two navigation systems

We evaluated the effectiveness of two navigation systems with optical tracking in endoscopic sinus surgery (ESS). The Signa SP/i Intraoperative navigation system (General Electric Co., Intraoperative NS) is advantageous in acquiring both real time and high-resolution images during surgery, compared to conventional image-guided navigation (Stealth Station TREON, Medtronic Inc., IGNS) that rely entirely on preoperative three-dimensional images. We studied the following in 14 patients treated with intraoperative NS and 19 treated with IGNS: 1) additional time for navigation system implementation, 2) available instrumentations in ESS, and 3) navigation system accuracy. Navigation systems required additional time to prepare ESS. The time lapse from admittance to the operating room to ESS onset was measured in patients under both systems and controls undergoing ESS without any image guidance. Preparation of the intraoperative NS required an additional 52 min and IGNS required 17 min compared to the control group. Based on operative instruments, the intraoperative NS has some limitations arising from the application of a high magnetic field. Surgical instruments must not be attracted by the magnetic field in the operating room. So those used in our study were thoroughly examined and some remanufactured using MR safe materials. All instruments in ESS could be used in surgical guidance during surgery in the IGNS. Anatomic landmarks were accurately visualized using intraoperative NS and IGNS. Intraoperative NS renews the image during surgery, so surgeons could confirm the surgical outcome during ESS. Since the average distant error in both systems was between 1 mm and 2.5 mm, we confirmed that accuracy obtained with both navigation system was suitable for ESS completion. The intraoperative NS renewed the image during navigation. In conclusion, both navigation systems are sufficient for accurate image navigation in ESS, but navigation systems must be selected based on the individual case.     

Navigation surgery in diseases of the paranasal sinuses

BACKGROUND: Since the mid-80s, endonasal sinus surgery has gained significant importance in the treatment of chronic inflammatory sinus disease. Many surgeons have recognized the necessity of developing new methods to increase the safety of this type of surgery. One of the advancements in increasing the safety of endonasal sinus surgery was the development of computer-aided surgical navigation (CAS) systems. METHODS: Since 1996, we have tried several different CAS systems for difficult surgical procedures in sinus and anterior skull base surgery, mainly revision surgery for chronic inflammatory sinusitis and endonasal tumors. During this time, we tried one electromagnetic ("Insta Trak") and two optoelectric systems ("Surgigate" and "Vector Vision"). RESULTS: In our experience, all systems can be used in endonasal sinus surgery; accuracy was satisfactory and varied between 0.1 and 0.5 mm. There were differences with respect to the time of preparation of the system for surgery as well as to the possibility to use different instruments. CONCLUSIONS: Computer-assisted surgical navigation systems today have gained a degree of accuracy which makes them not only suitable but almost necessary, at least for difficult surgical procedures at the anterior skull base, i.e. revision surgery in chronic inflammatory sinus disease. On the long run, these systems will become mandatory for these kinds of procedures. On the other hand, CAS systems cannot substitute thorough anatomical and surgical training.     

Microscopic endonasal surgery of the paranasal sinuses and the parasellar region

The anatomic principles and operative techniques currently applied to functional endoscopic endonasal surgery have allowed for significant refinements in another approach to regional pathology that uses the operating microscope, newly designed sinus instruments, and a self-retaining nasal speculum system. The main benefits of this method are the superb widefield stereoscopic vision and the distinct freedom to work bimanually. Additionally, direct bipolar cautery of bleeders is afforded while use of the observer tube or video allows for excellent teaching. The precise nature of this surgery affords less fear of serious complications in the treatment of periorbital, paranasal sinus, and parasellar diseases. We describe technical aspects of the surgery and associated complications in 219 patients treated from 1984 to 1987.     

Computer-aided surgery of the paranasal sinuses and the anterior skull base

Endoscopic or microscopic surgery for chronic rhinosinusitis with or without nasal polyps is a routine intervention in daily practice. It is often a delicate and difficult minimally invasive intervention in a narrow space, with a tunnel view of 4 mm in the case of endoscopy and frequent bleeding in chronically inflamed tissue. Therefore, orientation in such a "labyrinth" is often difficult. In the case of polyp recurrence or tumors, the normal anatomical landmarks are often missing, which renders orientation even more difficult. In such cases, computer-aided navigation together with images such as those from computed tomography or magnetic resonance imaging can support the surgeon to make the operation more accurate and, in some cases, faster. Computer-aided surgery also has great potential for education.     

Anatomic variations of the paranasal sinuses: CT examination for endoscopic sinus surgery

Chronic rhinosinusitis endoscopic surgery requires an accurate evaluation of diseases and paranasal sinus anatomic variations. This study aims to show the main anatomical variations in the ostiomeatal complex and paranasal sinuses which are usually depicted by computed tomography (CT). CT scans obtained 2 mm thickness in axial and coronal plane from a series of 200 patients with chronic sinusitis were examined to determine the prevalence of anatomic variants. Anatomical variations determined were supraorbital recess in 6%, concha bullosa in 30%, sphenomaxillary plate in 17%, infra-orbital ethmoid cells (Haller's cells) in 6%, spheno-ethmoid cells (Onodi's cells) in 12%, pneumatization of the anterior clinoid process in 6%, carotid artery bulging into the sphenoid sinus in 8%, pneumatization of the uncinate process in 2%, paradoxical curvature of the middle turbinate in 3% and septal deviation in 36%. Level difference between the ethmoid roof and nasal vault was an average of 8 mm in right side and 9.5 mm in left side. Awareness of these different variations will help the rhinologic surgeon in his orientation during endoscopic surgical procedures.     

功能性鼻窦内窥镜手术100例疗效观察

目的观察功能性鼻窦内窥镜手术的长期疗效.方法采用Messerklinger术式为100例患者手术;并以传统术式治疗100例作对照.结果内窥镜组临床治愈率81%,总有效率95%,明显优于传统手术组(P＜0.05),手术并发症发生率为6%,明显低于传统组(P＜0.05).结论内窥镜手术长期疗效可靠,并发症少,复发率低.     

Cholesteatoma of the nose and maxillary and ethmoid sinuses: a rare complication of palatal surgery

A 10-year-old boy presented with a complaint of a left-sided nasal obstruction with an associated foul-smelling discharge. Physical examination and anterior rhinoscopy revealed that a whitish, friable mass had completely filled the left nasal cavity. On computed tomography, a soft-tissue mass was seen filling the cavity and extending to the paranasal sinuses with bone erosion. A biopsy of the mass suggested that it represented a cholesteatoma. The lesion was removed via nasal endoscopy, and histopathology confirmed the diagnosis of a cholesteatoma. No recurrence was noted during 6 months of follow-up. Cholesteatoma of the paranasal sinuses is a rare entity, as only a few dozen cases have been reported in the literature.     

鼻内窥镜手术治疗非侵袭性鼻窦真菌病

目的 :探讨鼻内窥镜手术代替传统柯 陆手术治疗非侵袭性鼻窦真菌病的疗效。方法 :采用Storz30°鼻内窥镜行病侧钩突切除 ,扩大上颌窦开口 ,行下鼻道开窗 ,双进路清除病灶。术后用 1%H2 O2 及生理盐水冲洗 ,不用抗真菌药。结果 :2 9例随访 6个月～ 3年 ,原有症状消失 ,未见复发。结论 :采用鼻内窥镜手术治疗非侵袭性鼻窦真菌病 ,较之柯 陆手术创伤小、照明好、清除病灶准确 ;不损害鼻腔正常生理功能 ;保证鼻窦通气引流 ,减少复发 ,治愈率高     

鼻内窥镜手术治疗鼻窦炎疗效观察

目的观察鼻内窥镜手术治疗鼻窦炎的效果,研究提高鼻内窥镜鼻窦手术的疗效.方法对鼻窦炎患者进行鼻内窥镜手术及随访观察.结果参照FESS-97海口标准,治愈53例(53.9%),好转30例(28.9%),无效21例(20.2%).结论术前仔细研究鼻窦CT片,术后加强术腔清洁处理,是防止手术并发症和提高疗效的关键.