Clinical Review & Education Clinical Challenges in Otolaryngology
Invited Commentary CLINICAL CHALLENGES IN OTOLARYNGOLOGY
Extracapsular Dissection of Benign Parotid Tumors Daniel G. Deschler, MD
Iro and Zenk1 are to be commended on their concise and thorough discussion of the role of extracapsular dissection (ED) in the surgical management of benign parotid tumors. This discussion, as well as a review of the literature, supports their hypothesis that “ED is a safe and effective surgical technique in the management of benign Related article page 768 parotid neoplasms.” The true challenge is how best to incorporate this information and surgical technique into the global management of parotid tumors. Several points require consideration: the correct definition of the available and historical techniques for addressing parotid neoplasms, close analysis of the comparisons to date, a thorough understanding of the technique as well as evaluation of the relevant complication rates, and specific pitfalls associated with ED. Finally, as noted by all authors publishing on this procedure, significant expertise is required to successfully integrate ED into practice. Enucleation and nodulectomy should remain procedures of historical note and not be considered with current management techniques. The definition of ED is very specific with the goal of complete removal of the tumor with a 2- to 3-mm cuff of normal parotid tissue, if possible, and no formal identification of the nerve before tumor removal. Superficial parotidectomy implies dissection of all facial nerve branches and the removal of the entire superficial lobe; partial parotidectomy (PP) implies the dissection of only nerve branches that is required to safely remove the tumor with a cuff of normal parotid tissue surrounding it. Historically, the pendulum swung drastically away from enucleation procedures because of the high recurrence rates toward the thorough superficial parotidectomy, which advocated wide margins around tumors, yet required extensive facial nerve dissection. In an appropriate fashion, the pendulum has returned centrally with demonstration that effective control of benign parotid tumors can be achieved by PP, addressing only branches of the facial nerve system that are in anatomical proximity to the tumor and leaving a much smaller cuff of parotid tissue around the tumor.2 Extracapsular dissection represents the continuation of this principle by advocating the removal of the tumor with nerve dissection only when required. The end points for surgical management of parotid tumors are straightforward: complete tumor removal in a fashion to prevent recurrence and limitation of any facial muscular dysfunction related to nerve dissection. Minor complications include Frey syndrome, periauricular numbness, and contour deformity. The significant surgical experiences with ED indicate the nearly equitable success of this procedure compared with superficial parotidectomy regarding recurrence and final facial nerve function. Extracapsular dissection demonstrates less transient nerve dysfunction in 770
many series, which is understandable compared with the extensive facial nerve dissection that occurs with superficial parotidectomy.3 Directly comparing ED with appropriate PP procedures would be more informative and appropriate. Tumor recurrence rates and facial nerve function with ED must also take into account that most ED series involved significant selection bias, with smaller, mobile, and favorably selected tumors chosen to undergo ED and tumors that did not meet these criteria preoperatively or intraoperatively removed with superficial parotidectomy. These criteria clearly indicate that for ED to be successful, appropriate technique must be joined with excellent surgical decision making. The importance of capsular exposure in the management of benign parotid tumors continues to be a point of debate. Limited tumor exposure is common with all parotid surgeries and is not a significant risk factor for recurrence,4 whereas formal disruption and spillage of the tumor presents a risk for recurrence. The risk of potential disruption or spillage could increase with greater direct exposure of the tumor capsule– parotid interface during ED. For this reason, ED techniques used in experienced centers attempt to leave a small cuff of parotid tissue on the tumor, allowing ED to limit the welldescribed pathologic features of incomplete capsule, tumor pseudopodia, and tumor satellites. The lower rates of Frey syndrome reported with ED are understandable, but must be placed in the context of overall patient satisfaction and quality of life. The presence of gustatory sweating on starch iodine evaluation or by solicited patient history must be graded by its effect on the patient's life if avoidance of this limited complication is to become a potential driver for a change in surgical technique that has afforded excellent results. Similarly, issues related to contour and cosmetic appearance must be placed in context. Again, the major studies compared ED and superficial parotidectomy which, by definition, involves a greater resection of benign parotid tissue. Resultant contour deformities would be greatly lessened with an appropriate PP combined with simple regional tissue mobilization techniques. Clinical experience demonstrates successful subjective results equivalent to those noted by Iro and Zenk1 in their experience. Potential pitfalls specifically related to ED exist. The success of ED is intricately related to technological support including appropriate preoperative imaging and facial nerve monitoring, which can be variable throughout practice centers. The authors1 note that revision parotidectomy after ED would be an easier procedure with fewer potential complications compared with other interventions. After ED, identification of the main trunk of the facial nerve system as well as previously uninvolved nerve branches would be more straightforward. Yet, the facial nerve branches that were in close prox-
JAMA Otolaryngology–Head & Neck Surgery August 2014 Volume 140, Number 8
Copyright 2014 American Medical Association. All rights reserved.
Downloaded From: http://archotol.jamanetwork.com/ by a University of Georgia User on 06/09/2015
jamaotolaryngology.com
Clinical Challenges in Otolaryngology Clinical Review & Education
imity to the tumor at its original presentation would still require meticulous management, with challenges presented by postoperative scarring from the previous procedure. All proponents of ED appropriately note that this procedure should be reserved for benign disease, but we must be realistic that the accuracy of preoperative assessment, even in the context of advances in imaging and fine-needle aspiration techniques, is not 100%. This creates potential scenarios in which a tumor believed to be benign on preoperative assessment is found to be malignant. The decision to add adjuvant therapy is straightforward in malignant tumors that are large or have high-grade malignant histologic characteristics. The decision becomes more challenging when a small- to medium-sized, low-grade parotid malignant neoplasm that could have been removed with adequate margins via PP is excised using ED, revealing multiple areas of capsular exposure and potential microscopically positive margins. In such cases, radiotherapy could be required when PP would have afforded disease control with unimodality surgical therapy. A review of the Manchester experience5 demonstrated equal control rates in the limited series of malignant neoplasms discovered at the time of surgery or postoperatively. A far greater percentage of such tumors were in the superficial parotidectomy group, indicating a bias toward appropriately avoiding ED if features suggest that the tumors are malignant. Wide acceptance of the ED technique would require similar diligent deference. Finally, ED requires significant surgical expertise as well as thorough and experienced surgical judgment. Any practiARTICLE INFORMATION Author Affiliations: Division of Head and Neck Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston; Norman Knight Hyperbaric Medicine Center, Massachusetts Eye and Ear Infirmary, Boston; Department of Head and Neck Surgical Oncology, Massachusetts General Hospital, Boston; Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts. Corresponding Author: Daniel G. Deschler, MD, Division of Head and Neck Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114.
jamaotolaryngology.com
tioner who wishes to use ED must first have a significant experience and comfort level with traditional parotid surgery using facial nerve identification and atraumatic dissection. With traditional parotidectomy, decision making is fairly straightforward. The nerve is identified and the overlying parotid tissue is removed in a manner that encompasses the tumor. The key interface of dissection is primarily at the nerve and normal parotid, although particular care is required when the tumor is in close proximity to the nerve. With ED, the practitioner must constantly decide between 2 tissue interfaces: that of the tumor upon which the surgeon is attempting to leave a small amount of parotid tissue, and the facial nerve, which is not formally visualized but the surgeon is trying to avoid. While treading this fine line the practitioner may be seduced into accepting an increased risk of the late complication of tumor recurrence to avoid the immediate complication of potential facial nerve dysfunction. In summary, the literature indicates that ED can be used effectively and safely for select benign parotid tumors (≤2.5 cm, mobile, and located in the lateral and lower lobes of the gland) compared with standard superficial parotidectomy with a decreased incidence of Frey syndrome. The success of ED is intricately related to technological support including the use of loupe magnification, preoperative imaging, and facial nerve monitoring. Likewise, ED should not be the procedure of choice for surgeons with limited experience; the success of ED depends on preexisting surgical expertise with standard parotid surgery and experienced decision making.
Published Online: July 17, 2014. doi:10.1001/jamaoto.2014.1223. Conflict of Interest Disclosures: None reported. REFERENCES 1. Iro H, Zenk J. Role of extracapsular dissection in surgical management of benign parotid tumors [published online July 17, 2014]. JAMA Otolaryngol Head Neck Surg. doi:10.1001/jamaoto.2014.1218. 2. Zbären P, Vander Poorten V, Witt RL, et al. Pleomorphic adenoma of the parotid: formal parotidectomy or limited surgery? Am J Surg. 2013; 205(1):109-118.
3. Witt RL, Iacocca M. Comparing capsule exposure using extracapsular dissection with partial superficial parotidectomy for pleomorphic adenoma. Am J Otolaryngol. 2012;33(5):581-584. 4. Albergotti WG, Nguyen SA, Zenk J, Gillespie MB. Extracapsular dissection for benign parotid tumors: a meta-analysis. Laryngoscope. 2012;122(9):19541960. 5. McGurk M, Thomas BL, Renehan AG. Extracapsular dissection for clinically benign parotid lumps: reduced morbidity without oncologic compromise. Br J Cancer. 2003;89(9):1610-1613.
JAMA Otolaryngology–Head & Neck Surgery August 2014 Volume 140, Number 8
Copyright 2014 American Medical Association. All rights reserved.
Downloaded From: http://archotol.jamanetwork.com/ by a University of Georgia User on 06/09/2015
771
Invited Commentary CLINICAL CHALLENGES IN OTOLARYNGOLOGY
Extracapsular Dissection of Benign Parotid Tumors Daniel G. Deschler, MD
Iro and Zenk1 are to be commended on their concise and thorough discussion of the role of extracapsular dissection (ED) in the surgical management of benign parotid tumors. This discussion, as well as a review of the literature, supports their hypothesis that “ED is a safe and effective surgical technique in the management of benign Related article page 768 parotid neoplasms.” The true challenge is how best to incorporate this information and surgical technique into the global management of parotid tumors. Several points require consideration: the correct definition of the available and historical techniques for addressing parotid neoplasms, close analysis of the comparisons to date, a thorough understanding of the technique as well as evaluation of the relevant complication rates, and specific pitfalls associated with ED. Finally, as noted by all authors publishing on this procedure, significant expertise is required to successfully integrate ED into practice. Enucleation and nodulectomy should remain procedures of historical note and not be considered with current management techniques. The definition of ED is very specific with the goal of complete removal of the tumor with a 2- to 3-mm cuff of normal parotid tissue, if possible, and no formal identification of the nerve before tumor removal. Superficial parotidectomy implies dissection of all facial nerve branches and the removal of the entire superficial lobe; partial parotidectomy (PP) implies the dissection of only nerve branches that is required to safely remove the tumor with a cuff of normal parotid tissue surrounding it. Historically, the pendulum swung drastically away from enucleation procedures because of the high recurrence rates toward the thorough superficial parotidectomy, which advocated wide margins around tumors, yet required extensive facial nerve dissection. In an appropriate fashion, the pendulum has returned centrally with demonstration that effective control of benign parotid tumors can be achieved by PP, addressing only branches of the facial nerve system that are in anatomical proximity to the tumor and leaving a much smaller cuff of parotid tissue around the tumor.2 Extracapsular dissection represents the continuation of this principle by advocating the removal of the tumor with nerve dissection only when required. The end points for surgical management of parotid tumors are straightforward: complete tumor removal in a fashion to prevent recurrence and limitation of any facial muscular dysfunction related to nerve dissection. Minor complications include Frey syndrome, periauricular numbness, and contour deformity. The significant surgical experiences with ED indicate the nearly equitable success of this procedure compared with superficial parotidectomy regarding recurrence and final facial nerve function. Extracapsular dissection demonstrates less transient nerve dysfunction in 770
many series, which is understandable compared with the extensive facial nerve dissection that occurs with superficial parotidectomy.3 Directly comparing ED with appropriate PP procedures would be more informative and appropriate. Tumor recurrence rates and facial nerve function with ED must also take into account that most ED series involved significant selection bias, with smaller, mobile, and favorably selected tumors chosen to undergo ED and tumors that did not meet these criteria preoperatively or intraoperatively removed with superficial parotidectomy. These criteria clearly indicate that for ED to be successful, appropriate technique must be joined with excellent surgical decision making. The importance of capsular exposure in the management of benign parotid tumors continues to be a point of debate. Limited tumor exposure is common with all parotid surgeries and is not a significant risk factor for recurrence,4 whereas formal disruption and spillage of the tumor presents a risk for recurrence. The risk of potential disruption or spillage could increase with greater direct exposure of the tumor capsule– parotid interface during ED. For this reason, ED techniques used in experienced centers attempt to leave a small cuff of parotid tissue on the tumor, allowing ED to limit the welldescribed pathologic features of incomplete capsule, tumor pseudopodia, and tumor satellites. The lower rates of Frey syndrome reported with ED are understandable, but must be placed in the context of overall patient satisfaction and quality of life. The presence of gustatory sweating on starch iodine evaluation or by solicited patient history must be graded by its effect on the patient's life if avoidance of this limited complication is to become a potential driver for a change in surgical technique that has afforded excellent results. Similarly, issues related to contour and cosmetic appearance must be placed in context. Again, the major studies compared ED and superficial parotidectomy which, by definition, involves a greater resection of benign parotid tissue. Resultant contour deformities would be greatly lessened with an appropriate PP combined with simple regional tissue mobilization techniques. Clinical experience demonstrates successful subjective results equivalent to those noted by Iro and Zenk1 in their experience. Potential pitfalls specifically related to ED exist. The success of ED is intricately related to technological support including appropriate preoperative imaging and facial nerve monitoring, which can be variable throughout practice centers. The authors1 note that revision parotidectomy after ED would be an easier procedure with fewer potential complications compared with other interventions. After ED, identification of the main trunk of the facial nerve system as well as previously uninvolved nerve branches would be more straightforward. Yet, the facial nerve branches that were in close prox-
JAMA Otolaryngology–Head & Neck Surgery August 2014 Volume 140, Number 8
Copyright 2014 American Medical Association. All rights reserved.
Downloaded From: http://archotol.jamanetwork.com/ by a University of Georgia User on 06/09/2015
jamaotolaryngology.com
Clinical Challenges in Otolaryngology Clinical Review & Education
imity to the tumor at its original presentation would still require meticulous management, with challenges presented by postoperative scarring from the previous procedure. All proponents of ED appropriately note that this procedure should be reserved for benign disease, but we must be realistic that the accuracy of preoperative assessment, even in the context of advances in imaging and fine-needle aspiration techniques, is not 100%. This creates potential scenarios in which a tumor believed to be benign on preoperative assessment is found to be malignant. The decision to add adjuvant therapy is straightforward in malignant tumors that are large or have high-grade malignant histologic characteristics. The decision becomes more challenging when a small- to medium-sized, low-grade parotid malignant neoplasm that could have been removed with adequate margins via PP is excised using ED, revealing multiple areas of capsular exposure and potential microscopically positive margins. In such cases, radiotherapy could be required when PP would have afforded disease control with unimodality surgical therapy. A review of the Manchester experience5 demonstrated equal control rates in the limited series of malignant neoplasms discovered at the time of surgery or postoperatively. A far greater percentage of such tumors were in the superficial parotidectomy group, indicating a bias toward appropriately avoiding ED if features suggest that the tumors are malignant. Wide acceptance of the ED technique would require similar diligent deference. Finally, ED requires significant surgical expertise as well as thorough and experienced surgical judgment. Any practiARTICLE INFORMATION Author Affiliations: Division of Head and Neck Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston; Norman Knight Hyperbaric Medicine Center, Massachusetts Eye and Ear Infirmary, Boston; Department of Head and Neck Surgical Oncology, Massachusetts General Hospital, Boston; Department of Otology and Laryngology, Harvard Medical School, Boston, Massachusetts. Corresponding Author: Daniel G. Deschler, MD, Division of Head and Neck Surgery, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, 243 Charles St, Boston, MA 02114.
jamaotolaryngology.com
tioner who wishes to use ED must first have a significant experience and comfort level with traditional parotid surgery using facial nerve identification and atraumatic dissection. With traditional parotidectomy, decision making is fairly straightforward. The nerve is identified and the overlying parotid tissue is removed in a manner that encompasses the tumor. The key interface of dissection is primarily at the nerve and normal parotid, although particular care is required when the tumor is in close proximity to the nerve. With ED, the practitioner must constantly decide between 2 tissue interfaces: that of the tumor upon which the surgeon is attempting to leave a small amount of parotid tissue, and the facial nerve, which is not formally visualized but the surgeon is trying to avoid. While treading this fine line the practitioner may be seduced into accepting an increased risk of the late complication of tumor recurrence to avoid the immediate complication of potential facial nerve dysfunction. In summary, the literature indicates that ED can be used effectively and safely for select benign parotid tumors (≤2.5 cm, mobile, and located in the lateral and lower lobes of the gland) compared with standard superficial parotidectomy with a decreased incidence of Frey syndrome. The success of ED is intricately related to technological support including the use of loupe magnification, preoperative imaging, and facial nerve monitoring. Likewise, ED should not be the procedure of choice for surgeons with limited experience; the success of ED depends on preexisting surgical expertise with standard parotid surgery and experienced decision making.
Published Online: July 17, 2014. doi:10.1001/jamaoto.2014.1223. Conflict of Interest Disclosures: None reported. REFERENCES 1. Iro H, Zenk J. Role of extracapsular dissection in surgical management of benign parotid tumors [published online July 17, 2014]. JAMA Otolaryngol Head Neck Surg. doi:10.1001/jamaoto.2014.1218. 2. Zbären P, Vander Poorten V, Witt RL, et al. Pleomorphic adenoma of the parotid: formal parotidectomy or limited surgery? Am J Surg. 2013; 205(1):109-118.
3. Witt RL, Iacocca M. Comparing capsule exposure using extracapsular dissection with partial superficial parotidectomy for pleomorphic adenoma. Am J Otolaryngol. 2012;33(5):581-584. 4. Albergotti WG, Nguyen SA, Zenk J, Gillespie MB. Extracapsular dissection for benign parotid tumors: a meta-analysis. Laryngoscope. 2012;122(9):19541960. 5. McGurk M, Thomas BL, Renehan AG. Extracapsular dissection for clinically benign parotid lumps: reduced morbidity without oncologic compromise. Br J Cancer. 2003;89(9):1610-1613.
JAMA Otolaryngology–Head & Neck Surgery August 2014 Volume 140, Number 8
Copyright 2014 American Medical Association. All rights reserved.
Downloaded From: http://archotol.jamanetwork.com/ by a University of Georgia User on 06/09/2015
771
