Stieve M, Schwab B, Haupt C, Bisdas S, Heermann R, Lenarz Th
Department of Otolaryngology, Medical University of Hannover, Hannover, Germany.
Acta Otolaryngol. 2006 Jan;126(1):82-7. doi: 10.1080/00016480510040119.
Intraoperative CT surgery provides the surgeon with additional information about the altered surgical site in difficult anatomical situations. The skull base and lamina papyracea may be revealed by means of intraoperative CT, which may be beneficial in endonasal sinus surgery involving difficult surgical sites, although individual ethmoid cells cannot be assessed owing to blood artefacts. This provides the surgeon with valuable information that may facilitate the procedure considerably. In soft-tissue surgery it is advisable to apply a contrast agent in order to achieve good soft-tissue contrast, thus allowing the tumour to be adequately distinguished from benign tissue. The intraoperative application of CT is a fairly time-consuming procedure, partly owing to the preparation time (set-up of the appliance; 10-min warming-up phase) and partly due to the length of time required to calculate each image (15 s).
CT is a well-established imaging method for the assessment of osseous and soft-tissue structures in the head and neck region. Saving information and transferring it to the intraoperative site may, however, be problematic. Computer-assisted navigation systems are now able to assist difficult surgical procedures in the field of otolaryngology. To investigate the indications for intraoperative CT, we used it in various surgical procedures in the head and neck region.
Intraoperative CT was applied using the Tomoscan M in 46 cases in order to demonstrate the surgical benefit of the following procedures: endonasal surgical procedures on the paranasal sinuses (maxillary and ethmoidal sinusitis, anterior fracture of the sphenoidal sinus); tumour removal by means of laser surgery (carcinomas of the hypopharynx and larynx); and cochlear implantation (to verify the electrode position). After positioning the patient on the CT table, the workstation was set up in the operating theatre. If necessary, the gantry could be moved over the patient's head without repositioning the patient.
Intraoperative CT was used to assist in the exposure of the skull base and lamina papyracea in endonasal surgery of the paranasal sinuses. Individual ethmoidal sinuses could not be evaluated owing to blood artefacts. Intraoperative imaging proved particularly helpful in revision surgery for chronic sinusitis in cases with missing anatomical landmarks owing to previous surgeries, where there is an increased risk of inflicting damage to the skull base or orbita. The resection margins can be determined in craniofacial resections. In soft-tissue procedures, such as tumour removal by means of laser surgery, it proved possible to visualize the resection borders of malignant tumours. Assessment of the electrode position in cochlear implantation is particularly useful in revision cases and in cases of cochlear obliteration.
术中CT手术可为外科医生在解剖结构复杂的手术中提供有关手术部位变化的额外信息。术中CT可显示颅底和纸样板，这在涉及复杂手术部位的鼻内鼻窦手术中可能有益，尽管由于血液伪影无法评估单个筛窦。这为外科医生提供了有价值的信息，可能极大地促进手术进程。在软组织手术中，建议使用造影剂以获得良好的软组织对比度，从而使肿瘤能与良性组织充分区分。术中应用CT是一个相当耗时的过程，部分原因是准备时间（设备设置；10分钟预热阶段），部分原因是计算每张图像所需的时间（15秒）。
CT是评估头颈部骨和软组织结构的成熟成像方法。然而，保存信息并将其传输到手术部位可能存在问题。计算机辅助导航系统现在能够协助耳鼻喉科领域的复杂手术。为了研究术中CT的适应证，我们在头颈部的各种手术中使用了它。
在46例手术中使用Tomoscan M进行术中CT，以证明以下手术的益处：鼻内鼻窦手术（上颌窦和筛窦炎、蝶窦前骨折）；激光手术切除肿瘤（下咽和喉癌）；以及人工耳蜗植入（验证电极位置）。将患者安置在CT台上后，在手术室设置工作站。如有必要，扫描架可在不重新安置患者的情况下移至患者头部上方。
术中CT用于辅助鼻内鼻窦手术中颅底和纸样板的暴露。由于血液伪影，无法评估单个筛窦。术中成像在因先前手术导致解剖标志缺失的慢性鼻窦炎翻修手术中特别有用，在这种情况下损伤颅底或眼眶的风险增加。在颅面切除术中可以确定切除边缘。在软组织手术中，如激光手术切除肿瘤，证明可以可视化恶性肿瘤的切除边界。人工耳蜗植入中电极位置的评估在翻修病例和耳蜗闭塞病例中特别有用。
