eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > Head & Neck Surgery
Sentinel Lymph Node Biopsy in Patients With Squamous Cell Carcinoma
Updated: May 22, 2008
Introduction
Cutaneous squamous cell carcinoma (SCC) is a malignant tumor of keratinizing epidermal cells. This type of skin cancer is the second leading cause of death after melanoma, and it is the second most common type of nonmelanoma skin cancer after basal cell carcinoma.
Most SCCs occur on the sun-exposed areas of the head and the neck. The most common route of spread for metastatic SCC is lymphatic in nature. In SCC of the upper aerodigestive tract, especially the neck, both the investigation and the treatment of a patient with a clinically N0 neck remain controversial. Depending on the classification of the tumor according to the TNM staging system, approximately 30% of patients with SCC of the head and neck have subclinical metastases in the neck, and knowledge of lymph node disease alters management.
Although CT scanning and MRI are commonly used to classify tumors of the neck, their overall accuracy is limited. The only highly accurate means of identifying lymph node disease is to perform a staging lymph node dissection. For disease in its early stages, clinicians are reluctant to perform an elective lymph node dissection because of the associated morbidity and lack of beneficial effects.
The sentinel lymph node (SLN) is the first lymph node to drain a metastatic tumor cell that drains via the lymphatic route. The concept of the SLN is based on the orderly progression of tumor cells within the lymphatic system. Mapping of the lymph flow from the tumor site to the regional lymphatic drainage area can be used to identify the primary draining lymph node (ie, SLN). If the SLN can be identified and examined for the presence of tumor metastases, an elective lymph node dissection for staging does not need to be performed.
History of the Procedure
The concept of the SLN originated in 1977 when Cabanas described mapping of the first lymph node–draining penile carcinoma. In 1977, Robinson et al described the use of cutaneous lymphoscintigraphy in the nodal basin for truncal melanomas using colloidal gold scanning. The development of lymphatic mapping at the end of the 1980s was a breakthrough in making the sentinel node concept applicable to various types of malignancies.
In 1993, Alex et al introduced the use of technetium Tc 99m sulfur colloid, a radioactive tracer, which is injected intradermally around a primary melanoma site, followed by an imaging study and subsequent intraoperative use of a gamma probe to localize the sentinel node.[1 ]Initial results of the SLN procedure in carcinoma of the head and the neck have been reported with mixed success. In a series of cases using radiocolloid alone, Koch et al remained unconvinced of its role in the management of patients with carcinoma of the head and the neck.[2 ]Pitman et al were unable to find any lymph nodes that stained blue in patients who were injected with blue dye alone.[3 ]Alex and Krag performed the first successful SLN biopsy of the head and the neck on a patient with a supraglottic carcinoma.[4 ]
Problem
Approximately 100,000 cases of SCC are diagnosed in the United States each year. Approximately 80% of ultraviolet light–induced SCCs develop on the arms, head, or neck.
Frequency
The frequency of cutaneous SCC, as with all nonmelanoma skin cancers, is increasing.
Etiology
Any of the following may cause SCC: exposure to sunlight; chemical carcinogens, such as arsenic and hydrocarbons; human papillomavirus; ionizing radiation; cigarette smoke; chronic irritation or ulceration; or alcohol. In addition, immunocompromised patients have a much higher risk of developing SCC. Two genes, PATCHED and TP53, have been identified that usually prevent cancers but are inactivated in patients with SCC; TP53 is mutated in more than 90% of patients with SCC.
Pathophysiology
SCC arises from basal keratinocytes of the skin. It typically manifests as a firm nodule on an erythematous base with elevated borders and insidious margins. Central ulceration or crusting may be present. Irregular nests of epidermal cells invading the dermis in varying degrees characterize SCC. Grading is based on the degree of cell differentiation. The most common route of spread for metastatic SCC is lymphatic in nature.
Presentation
SCCs of the skin typically manifest on the head, neck, or arms. They usually have elevated and rolled edges with central ulceration. Well-differentiated SCCs are likely to manifest as firm erythematous nodules of varying sizes, sometimes with an area of central hyperkeratosis. The tumor is usually firm, although tumors in more advanced cases can be soft and friable. Erosion and ulceration are more common with SCCs. Poorly differentiated SCCs are more apt to manifest as faintly erythematous nodules or plaques that are not well defined; ulceration is also common.
Indications
Elective dissection of a clinically negative (ie, N0) neck causes overtreatment for most patients, while no equivocal advantage in survival has been demonstrated when compared with a delayed dissection for patients with metastases in the neck. SLN biopsy can help determine the presence of lymph node metastases in patients with T1-T2, N0 oral and oropharyngeal SCCs.
Relevant Anatomy
SCCs of the skin typically manifest on sun-exposed areas of the head, neck, or arms.
Contraindications
Contraindications to a SLN biopsy are a palpable lymph node, tumors larger than 4-5 cm, disruption of lymphatic drainage, prior extensive surgery (eg, dissection of the neck), previous radiation to the head and the neck, and allergy to dye.
Workup
Imaging Studies
- Contrast-enhanced CT scanning helpful for determining the extent of tumor infiltration. Detection of grossly positive nodal disease, particularly when central necrosis is present, is enhanced with contrast-enhanced CT scans. The accuracy for detecting nodal metastases is reportedly improved from 70% to 93% when a physical examination is combined with CT scans, but occult disease can still be missed.
- Fluorodeoxyglucose-positron emission tomography is performed before removal of the primary tumor and/or dissection of the neck, and results are compared with those from histopathology studies. Fluorodeoxyglucose-positron emission tomography confirms the clinically identified location of the primary tumor site. Fluorodeoxyglucose-positron emission tomography shows promise in the initial staging of cancer of the head and the neck. It also provides additional accuracy to the conventional staging process using CT scans.
- MRI is beneficial for staging the size of the suggestive lymph nodes, for the evaluation of central lucency reflecting necrosis, for the assessment of irregular nodes with rim enhancement, for the evaluation of indistinct nodal margins, and for obliteration of fat or tissue planes.
Other Tests
Imaging studies are performed to detect any lymph node metastases. If the imaging studies fail to positively show lymph node metastases, a SLN biopsy is indicated for oral and oropharyngeal SCCs.
Histologic Findings
The current histopathologic routine is to step-section the SLNs at multiple levels and to perform immunohistochemical staining with S-100 protein and homatropine methylbromide to identify micrometastatic disease. If any question remains about abnormal cells after the first sections are taken, additional sections are obtained. Immunohistochemistry results identify an additional 10-20% of patients with positive SLNs, in whom micrometastases are not seen on routine sections stained with permanent hematoxylin and eosin (H&E). At least some of the increased rate of detection of micrometastatic disease is attributable to step-sectioning at multiple levels.
The approach for sampling involves bivalving the lymph node, fixing the 2 halves face down, and subsequently sectioning each half into 10 sections, which are alternately used for H&E staining, immunohistochemistry testing, and molecular staging. The sensitivity of intraoperative frozen section examination of the SLN is disappointingly low (<50%), although false-positive results are almost never reported. Because of concerns about tissue loss during the frozen section procedure, most centers eschew frozen sections and rely on permanent sections, except to confirm grossly suggestive metastatic disease.
Staging
Lymph node groups of the neck region are divided into 2 triangles, the anterior and the posterior triangles, which are further subdivided as follows:
- The anterior triangle of the neck is bounded (1) anteriorly by the median plane, (2) posteriorly by the sternocleidomastoid muscle, and (3) superiorly by the base of the mandible. Also, a line joins the angle of the mandible to the mastoid process. The apex of the triangle lies above the manubrium sterni. The anterior triangle is subdivided by the digastric muscle and the superior belly of the omohyoid into the submental triangle, the digastric triangle, the carotid triangle, and the muscular triangle.
- The submental triangle is the median triangle. On each side, the boundaries are the anterior belly of the corresponding digastric muscles. Its base is formed by the body of the hyoid bone. Its apex lies at the chin. The floor of the triangle is formed by the right and left mylohyoid muscles, with the median raphe uniting them.
- The digastric triangle boundaries are, anteroinferiorly, the anterior belly of the digastric; posteroinferiorly, the posterior belly of the digastric and the stylohyoid; and superiorly (base), the base of the mandible and a line joining the angle of the mandible to the mastoid process. The roof boundary is the skin, superficial fascia, and deep fascia. The floor is formed by the mylohyoid muscle anteriorly and by the hyoglossus posteriorly and anteroinferiorly.
- The carotid triangle boundaries are, superiorly, the posterior belly of the digastric muscle and the stylohyoid; anteroinferiorly, the superior belly of the omohyoid; and posteriorly, the anterior border of the sternocleidomastoid muscle. The roof boundary is skin, superficial fascia, and an investing layer of deep fascia. The floor is formed by parts of the thyrohyoid muscle, the hyoglossus, and the middle and inferior constrictors of the pharynx. Most of the SLNs are found in the carotid or the digastric triangle.
- The muscular triangle includes the superficial structures in the infrahyoid region. The boundaries are, anteriorly, the anterior median line of the neck from the hyoid bone to the sternum; posterosuperiorly, the superior belly of the omohyoid muscle; and posteroinferiorly, the anterior border of the sternocleidal mastoid muscle.
- The posterior triangle is a space on the side of the neck situated behind the sternocleidomastoid muscle. The boundaries are, (1) anteriorly, the posterior border of the sternocleidomastoid muscle; (2) posteriorly, the anterior body of the trapezius; and (3) inferiorly (base), the middle third of the clavicle. The apex lies on the superior nuchal line where the trapezius and sternocleidomastoid muscle meet. The posterior triangle is subdivided by the inferior belly of the omohyoid into the omohyoid triangle and the supraclavicular triangle. Lymph node dissection in both the triangles in the posterior compartment is considered to be the same level.
Treatment
Preoperative Details
Patients undergo lymphoscintigraphy up to 1 day prior to surgery. A maximum of 40 MBq99m Tc-labeled human serum albumin (ie, AlbuRES, Nanocoll) is injected throughout the normal mucosa surrounding the tumor edge and the submucosa on the deep aspect of the tumor in a volume of approximately 0.5-1 mL. A syringe with a permanently secured needle is used for injection, thereby preventing inadvertent spillage of colloid into the mouth. Colloid is injected at as many points as necessary in an attempt to completely surround the tumor. A mouthwash is used immediately following injection to prevent pooling or swallowing of residual radioactive material by the patient.
Static lymphoscintigraphy is performed at 15 minutes, 30 minutes, and 1 hour postinjection in 2 planes or until the appearance of radioactive nodes. Hot spots are usually seen 15 minutes postinjection. If nodes are still absent 1 hour after injection, the lymph nodes are too close to the injection site or radiocolloid has leaked out of the injection site.
Either a cobalt Co 57 marker is used to trace the patient outline or a flood source of57 Co or99m Tc is placed behind the patient to produce a silhouette of the patient outline. In light of the radiation dose, the marker pen is preferable. A gamma camera fitted with a low-energy, general-purpose collimator is used to acquire images of the patient. A 20% window centered on the 140 keV photopeak is selected, and the camera is interfaced to a suitable computing system. The locations of radioactive lymph nodes are marked on the patient's skin, the position of a57 Co solid-source pen is observed on the camera's persistence display, and the pen is moved until its position overlies a radioactive node. This position is then marked on the patient's skin using indelible ink. During the skin marking, a lead plate of an appropriate thickness (eg, 3 mm) is used to shield the injection site.
Following image acquisition, a software mask is applied to all images to eliminate radioactivity from the injection site. A region of interest, drawn around the image of the site of injection, is used as the basis for the mask applied.
Two colloids are commonly used for lymphoscintigraphy: AlbuRES and Nanocoll. AlbuRES has a mean particle size of 500 nm and is a slower-moving particle that remains in first-echelon (sentinel) nodes but requires a high density of terminal lymphatic vessels at the injection site. For these reasons, AlbuRES is the colloid of choice on the tongue and on the floor of the mouth. Nanocolloid has a mean particle size of 50 nm and is a faster-moving colloid, which finds lymphatic vessels despite injection into tissues with low densities of terminal lymphatics. Nanocolloid also moves readily from sentinel nodes to subsequent-echelon nodes. For these reasons, nanocolloid is the colloid of choice for primary tumors that are not located on the floor of the mouth or on the tongue. Record the choice of colloid.
The overall success rate of a SLN biopsy by blue dye is 82%, by radioactive mapping is 94%, and by a combination of both is 98%.
Intraoperative Details
At operation, 1-2 mL of Patent Blue V dye may be used. To approximate the same injection sites as for radiocolloid, ensure that the same person performs all the injections. A suitable incision is made in the neck in such a position as to facilitate excision of the incision scar if a subsequent neck dissection is necessary.
The handheld gamma probe is used to identify radioactive sentinel nodes, including those marked preoperatively during lymphoscintigraphy. To reduce detection of radiation from the injection site, a series of malleable, sterilized lead plates may be used to mask the injection site, thus aiding in vivo identification of radioactive nodes. Radioactive nodes are excised, and radioactivity within the node is confirmed ex vivo.
If the blue dye is used, stained lymphatics, if seen, are followed to the first draining lymph node, which is then harvested. Sentinel nodes are labeled according to their color and radioactivity. The anatomic neck level of the sentinel nodes is noted. Although sentinel nodes are usually harvested prior to treatment of the primary tumor, the proximity of the sentinel node to the injection site may require a further search for sentinel nodes following excision of the primary tumor. If sentinel nodes are sought after excision of the injection site, the nodes are not likely to be stained blue.
Because of the relatively high radioactivity present in the injection sites and the proximity to the sentinel node, detection of scattered radiation must be avoided as far as possible. In addition to the use of the lead plates described above, the gamma probe must have a well-collimated detector, which excludes gamma radiation except over a small angle in front of it. Set the pulse-height analysis window to only include the99m Tc photopeak with a cutoff on the low-energy side at approximately 130 keV. Check the calibration at regular intervals of not more than 1 month (depending on the make and model of the instrument). Devise a quick check of calibration, and perform this quick check before each use. Calling on appropriate scientific or technical assistance may be necessary to ensure that the gamma probe is at its optimal settings and to make an estimate of its sensitivity at these settings.
Sentinel nodes are fixed in 10% neutral, buffered formalin, and, after fixation, they are bisected through the hilum (if identifiable) or through the long axis of the node. If the halves are thicker than 2 mm, the slices are further trimmed to provide additional blocks of 2 mm. If sentinel nodes are found to be free from tumor after the initial histologic examination, step-serial sections are prepared at an additional 6 levels in the block at intervals of approximately 150 µm. One H&E-stained section is prepared at each level. If the nodes still appear negative after histologic examination, an adjacent section from each level is examined by immunocytochemistry using the multicytokeratin antibody AE1/AE3.
The interpretation of the histopathology and immunocytochemistry results for the SLN is categorized as follows:
- Pathology code description
- Stage 1: The sample is positive for tumor upon first examination using H&E stain.
- Stage 2: The sample initially appears negative for tumor, but it is noted to be positive for tumor upon examination of the H&E stain of step-serial sections.
- Stage 3: The sample is negative for tumor at stages 1 and 2 but positive for tumor based on immunohistochemistry results. To be categorized as positive for tumor, cells must be present that are (1) positive based on immunocytochemistry results and (2) cytologically observed to be nucleated cells with the characteristics of viable epithelial cells in both the immunocytochemical preparation and the serial H&E-stained sections. Cytokeratin positivity lacking the cytological features of viable tumor cells is categorized as stage 4.
- Stage 4: Cytokeratin positivity does not show the features of viable tumor cells. This positivity likely represents either dying tumor cells (possibly apoptotic cells), characterized by eosinophilic bodies lacking normal nuclei, or macrophages with phagocytosed tumor products. Usually, these cells are single and not in small, cohesive groups. The decision to allocate nodes to this category requires careful comparison of the serial H&E-stained section and the immunocytochemical preparation.
- Stage 5: The sample is negative for tumor at all stages.
If any lymph node contains a viable tumor (ie, stages 1-3 according to the pathology code description) either based on routine histology studies or based on immunohistochemistry and multiple sectioning, the patient undergoes a radical or modified radical dissection of the neck. Perform the dissection of the neck within 4 weeks of the SLN biopsy, and begin any adjuvant radiotherapy within 6 weeks of the dissection. Do not administer radiotherapy prior to a neck dissection.
For tumors in stage 4 or 5 according to the pathology code description, no further treatment to the neck is required and no prophylactic neck radiotherapy or additional surgery is necessary.
Postoperative Details
The current treatment for patients with SCC includes a proper diagnosis based on a high level of consideration and examination, with subsequent staging and development of a treatment paradigm. A treatment program of surgery, radiation, or chemotherapy is best developed by an oncology team that includes surgeons, radiation and medical oncologists, and rehabilitative specialists who all have significant experience in the care of patients with cancer involving the head and the neck. By using this approach, new protocols and surgical options can be appropriately offered to those patients with advanced cancers.
Follow-up
Patients are seen every 3 months for the first year, every 4 months for the following 2 years, and every 6 months until 5 years following a SLN biopsy. At any stage, if nodal disease is detected, patients can elect to undergo surgical treatment of the neck.
For excellent patient education resources, visit eMedicine's Cancer and Tumors Center. Also, see eMedicine's patient education articles Skin Cancer, Skin Biopsy, and Cancer of the Mouth and Throat.
Complications
Allergic reactions to isosulfan blue, nerve injury, lymphedema, neuropathy, fat necrosis, seroma, and hematoma can result following dissection of an SLN.
Outcome and Prognosis
The SLN biopsy can be a valuable staging technique for patients with SCC whose lymphatic drainage of the neck has not been altered by previous surgery or radiotherapy. It provides reliable detection of micrometastasis, indicating which levels should be removed ipsilaterally or contralaterally. This technique also allows the surgeon to accurately plan a dissection of the neck, taking into consideration the pattern of lymphatic drainage of each patient. In this way, unnecessary dissection of the neck and its morphofunctional sequelae can be avoided in numerous patients.
The cumulative results of all those who contributed to the first international conference on SLN biopsy of mucosal cancer of the head and the neck confirm that SLN biopsy has a role in staging the clinically N0 neck, and it has a similar sensitivity to that of a neck dissection for staging.
Future and Controversies
Defining a successful SLN biopsy accurately is critical. Although some studies have examined the impact of an individual surgeon's experience on the SLN identification rate, SLN identification is clearly not an appropriate endpoint; many studies have documented excellent SLN identification rates with unacceptably high false-negative rates. The more important issue is the experience required to achieve an acceptably low false-negative rate. In cases in which the pathology results from the scintigram are unclear or are negative, a formal elective neck dissection should be considered for staging purposes.
This procedure is multidisciplinary. As such, surgeons must ensure that nuclear medicine specialists, radiologists, and pathologists are actively involved with the successful implementation of this new technology. The learning curve for individual surgeons is undoubtedly associated with the experience levels of specialists within the multidisciplinary team. The implications of the SLN procedure must be effectively communicated to radiation oncologists and medical oncologists. The coordination of effort among the various specialists in each discipline is an essential component of the learning process.
The role of the SLN biopsy in the management of SCC of the head and the neck will evolve as more centers accept it as a standard of care.
References
Alex JC, Weaver DL, Fairbank JT, et al. Gamma-probe-guided lymph node localization in malignant melanoma. Surg Oncol. Oct 1993;2(5):303-8. [Medline].
Koch WM, Choti MA, Civelek AC, et al. Gamma probe-directed biopsy of the sentinel node in oral squamous cell carcinoma. Arch Otolaryngol Head Neck Surg. Apr 1998;124(4):455-9. [Medline].
Pitman KT, Johnson JT, Edington H, et al. Lymphatic mapping with isosulfan blue dye in squamous cell carcinoma of the head and neck. Arch Otolaryngol Head Neck Surg. Jul 1998;124(7):790-3. [Medline].
Alex JC, Krag DN. The gamma-probe-guided resection of radiolabeled primary lymph nodes. Surg Oncol Clin N Am. Jan 1996;5(1):33-41. [Medline].
Alex JC, Sasaki CT, Krag DN, et al. Sentinel lymph node radiolocalization in head and neck squamous cell carcinoma. Laryngoscope. Feb 2000;110(2 Pt 1):198-203. [Medline].
Asthana S, Deo SV, Shukla NK. Intraoperative neck staging using sentinel node biopsy and imprint cytology in oral cancer. Head Neck. May 2003;25(5):368-72. [Medline].
Civantos FJ, Gomez C, Duque C. Sentinel node biopsy in oral cavity cancer: correlation with PET scan and immunohistochemistry. Head Neck. Jan 2003;25(1):1-9. [Medline].
Cochran AJ, Wen DR, Farzad Z, et al. Immunosuppression by melanoma cells as a factor in the generation of metastatic disease. Anticancer Res. Jul-Aug 1989;9(4):859-64. [Medline].
Hughes CJ, Gallo O, Spiro RH, Shah JP. Management of occult neck metastases in oral cavity squamous carcinoma. Am J Surg. Oct 1993;166(4):380-3. [Medline].
Kontio R, Leivo I, Leppänen E. Sentinel lymph node biopsy in oral cavity squamous cell carcinoma without clinically evident metastasis. Head Neck. Jan 2004;26(1):16-21. [Medline].
Kovács AF. Head and neck squamous cell carcinoma: sentinel node or selective neck dissection. Surg Oncol Clin N Am. Jan 2007;16(1):81-100. [Medline].
Martinez JC, Cook JL. High-risk cutaneous squamous cell carcinoma without palpable lymphadenopathy: is there a therapeutic role for elective neck dissection?. Dermatol Surg. Apr 2007;33(4):410-20. [Medline].
Morton DL, Wen DR, Wong JH, et al. Technical details of intraoperative lymphatic mapping for early stage melanoma. Arch Surg. Apr 1992;127(4):392-9. [Medline].
Pillsbury HC 3rd, Clark M. A rationale for therapy of the N0 neck. Laryngoscope. Oct 1997;107(10):1294-315. [Medline].
Reintgen D, Cruse CW, Wells K, et al. The orderly progression of melanoma nodal metastases. Ann Surg. Dec 1994;220(6):759-67. [Medline].
Ross GL, Shoaib T, Scott J, et al. The learning curve for sentinel node biopsy in malignant melanoma. Br J Plast Surg. Jun 2002;55(4):298-301. [Medline].
Ross GL, Shoaib T, Soutar DS, et al. The First International Conference on Sentinel Node Biopsy in Mucosal Head and Neck Cancer and adoption of a multicenter trial protocol. Ann Surg Oncol. May 2002;9(4):406-10. [Medline].
Shah JP, Andersen PE. Evolving role of modifications in neck dissection for oral squamous carcinoma. Br J Oral Maxillofac Surg. Feb 1995;33(1):3-8. [Medline].
Shoaib T, Soutar DS, MacDonald DG, et al. The accuracy of head and neck carcinoma sentinel lymph node biopsy in the clinically N0 neck. Cancer. Jun 1 2001;91(11):2077-83. [Medline].
Werner JA, Dünne AA, Ramaswamy A, Dalchow C, Behr T, Moll R, et al. The sentinel node concept in head and neck cancer: solution for the controversies in the N0 neck?. Head Neck. Jul 2004;26(7):603-11. [Medline].
Woolgar JA, Vaughan ED, Scott J, Brown JS. Pathological findings in clinically false-negative and false-positive neck dissections for oral carcinoma. Ann R Coll Surg Engl. Jul 1994;76(4):237-44. [Medline].
Keywords
sentinel lymph node biopsy in patients with squamous cell carcinoma, sentinel node, SN, SLN, SLN biopsy, SLN mapping, sentinel lymph node mapping, skin malignancy, skin cancer, skin squamous cell cancer, squamous cell skin cancer, skin cancer diagnosis, skin SCC, squamous cell carcinoma, SCC, squamous skin cancer, SC cancer, cutaneous SCC, cutaneous squamous cell carcinoma, sun exposure, lymph node disease, lymph node cancer, head and neck SCC, head and neck cancer, head and neck carcinoma, head and neck malignancy, head and neck squamous cell carcinoma, lymph node dissection
Contributor Information and Disclosures
Author
Amit Dwivedi, MD, Assistant Professor of Surgery, University of Louisville
Amit Dwivedi, MD is a member of the following medical societies: American College of Surgeons and American Medical Association
Disclosure: Nothing to disclose.
Coauthor(s)
Karl J D'Silva, MD, Fellow in Hematology/Oncology, Department of Internal Medicine, Breslin Cancer Center, Michigan State University
Karl J D'Silva, MD is a member of the following medical societies: Massachusetts Medical Society
Disclosure: Nothing to disclose.
Nafisa K Kuwajerwala, MD, Staff Surgeon, Breast Oncology, William Beaumont Hospital
Nafisa K Kuwajerwala, MD is a member of the following medical societies: American College of Surgeons
Disclosure: Nothing to disclose.
Thabet Abbarah, MD, FACS, Consulting Staff, Department of Otolaryngology, North Oakland Medical Centers
Thabet Abbarah, MD, FACS is a member of the following medical societies: American College of Surgeons
Disclosure: Nothing to disclose.
Medical Editor
M Abraham Kuriakose, MD, DDS, FRCS, Chairman, Head and Neck Institute, Amrita Institute of Medical Sciences
M Abraham Kuriakose, MD, DDS, FRCS is a member of the following medical societies: American Association for Cancer Research, American Head and Neck Society, British Association of Oral and Maxillofacial Surgeons, and Royal College of Surgeons of England
Disclosure: Nothing to disclose.
Pharmacy Editor
Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.
Managing Editor
Nader Sadeghi, MD, FRCS(C), Associate Professor of Surgery, Director of Head and Neck Surgery, Division of Otolaryngology, George Washington University
Nader Sadeghi, MD, FRCS(C) is a member of the following medical societies: American Academy of Otolaryngology-Head and Neck Surgery, American Head and Neck Society, Federation of Medical Specialists in Quebec, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.
CME Editor
Christopher L Slack, MD, Otolaryngology-Facial Plastic Surgery, Private Practice, Associated Coastal ENT; Medical Director, Treasure Coast Sleep Disorders
Christopher L Slack, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, and American Medical Association
Disclosure: Nothing to disclose.
Chief Editor
Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine
Arlen D Meyers, MD, MBA is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery, American Academy of Otolaryngology-Head and Neck Surgery, and American Head and Neck Society
Disclosure: Advanced Headache Intervention Consulting fee Consulting; Covidien Corp Consulting fee Consulting
© 1994-
by Medscape.
All Rights Reserved
(http://www.medscape.com/public/copyright)