Advances in radiologic imaging have significantly augmented the practitioner's diagnostic and therapeutic capabilities in otolaryngologic surgery. This is manifest in two particular areas: (1) in-office CT scanning or point-of-care CT (POC-CT), and (2) intraoperative CT scanning (IO-CT).
POC-CT is notably useful in the work-up of patients presenting with historical symptoms suggestive of paranasal sinus inflammation. Many patients presenting with symptoms of nasal blockage, nasal drainage, facial pressure, and/or cough are empirically diagnosed as having sinusitis, while in many cases, the process reflects allergies, viral upper respiratory infection, or non-otolaryngologic conditions such as tension headache, migraine, or temporomandibular joint dysfunction. Previously, these patients were often treated with broad spectrum antibiotics empirically and CT was reserved for refractory cases. The speed and availability of POC-CT permits sinusitis to be confirmed or ruled out prior to initiating such therapy. POC-CT utilizes cone beam technology which acquires the equivalent of >100 axial slices in approximately 1 minute at an effective resolution of 0.3mm or less. The equipment occupies a space of 8'x10' and can thus be accommodated in almost any office setting (Figure 1). Perhaps most importantly, the radiation dosing for even the most sophisticated protocol is 0.17 mSv, which is < 10% of the dose of a conventional head CT and equivalent to approximately 20 days of background radiation. One theoretical shortcoming of this technology is that it does not permit soft tissue imaging. This is seldom a concern in sinonasal evaluation, as this is typically undertaken in bone windows. The acquired data is immediately formatted into triplanar (axial, sagittal, coronal) reconstructions and is also compatible with devices used for intraoperative stereotactic navigation. Imaging of the temporal bone for evaluation of middle ear structures can be performed via POC-CT as well.
Complex pathology of the paranasal sinuses, temporal bone, and skull base is increasingly managed via minimally invasive surgical approaches. IO-CT scanning has been a useful complement to endoscopy in these procedures. IO-CT utilizes potable cone beam technology. The intraoperative acquired data can guide surgical decision-making and also may be used to update the stereotactic navigation. Current market entries vary in size and true portability (Figure 2), and use of some devices is limited by the patient's body habitus (the scan may not be feasible in obese patients). IO-CT technology is also somewhat hampered in that those devices that have soft tissue imaging capabilities are also less portable and adaptable to patients of large girth. Nonetheless, this technology has a potential role in the resection of bone-density structures and can help guide surgical decision making to assure completeness of resection and proximity to critical anatomic structures, such as the optic canal.
The most notable recent developments in the field of head and neck cancer have focused on the impact of human papillomavirus (HPV) in patients with oropharyngeal carcinoma and the use of robotics in head and neck surgery.
The incidence of oropharyngeal squamous cell carcinoma has increased significantly over the last 3 decades. The etiology for this rise has been attributed to the HPV-16 related development of malignancy. HPV infection can induce the production of two viral oncoproteins, E6 and E7, which inactivate tumor suppressors p53 and Rb leading to tumor promotion. In a prospective clinical trial of patients enrolled in the Eastern Cooperative Group (ECOG) trial 2399, Fakhry et al reported on the survival benefit seen in oropharyngeal cancer patients that were HPV-positive. Patients were treated with sequential chemoradiation for advanced stage disease. HPV positivity was found in 57% of all oropharyngeal cancers in the study. HPV-positive cancers demonstrated a higher response rate to induction chemotherapy (82% vs. 55) and improved 2-year survival (95% vs. 62%). Compared to patients with HPV-negative tumors, HPV-positive cancers presented in younger male patients and were associated with a history of higher lifetime number of sexual partners and oral sex. HPV-associated oropharyngeal carcinoma is considered to represents a distinct clinicopathologic entity different from the traditional squamous cell carcinoma of the head and neck associated with the long-term use of tobacco and alcohol ( Table 1 ). Surprisingly, the rate of distant metastasis is similar in HPV-positive and HPV-negative patients indicating that survival benefits are likely from improved locoregional control with treatment. Clinical trials are currently being performed to assess if therapy can be de-intensified in the HPV patient population while obtaining the same locoregional and overall survival seen with standard treatment options.
In an effort to resect tumors of the oropharynx in a minimally invasive fashion, which might otherwise require a lip-splitting mandibulotomy approach with dissection through the floor of mouth, the transoral robotic surgical approach utilizing the da Vinci Surgical System has been utilized with favorable results. Dean et al reported on the use of robot-assisted primary and salvage surgery for 36 patients with T1 and T2 tumors of the oropharynx compared to traditional open salvage resection. Patients who underwent robot-assisted surgery had shorter lengths of stay and were less likely to be gastrostomy tube or tracheostomy dependent at 6 months. Of patients undergoing primary transoral robotic surgery to tonsillar carcinoma, 93% still required some form of postoperative adjuvant therapy. Advocates of the technique believe that initial surgical management of the oropharynx, a site typically treated with primary radiation or chemoradiation therapy, allows for a better long-term functional result with the potential for decreasing the intensity of adjuvant therapy to radiation alone as opposed to postoperative chemoradiation. Clinical trials and experience with the technique continue to evolve with the focus of use directed at early-stage oropharyngeal carcinomas.
AccessMedicine from McGraw-Hill © 2011 The McGraw-Hill Companies
All rights reserved. From Tintinalli's Emergency Medicine
Cite this: Advances in Otolaryngology-Head and Neck Surgery - Medscape - Apr 26, 2011.