Clinical Review & Education
Clinical Challenges in Otolaryngology
Role of Extracapsular Dissection in Surgical Management of Benign Parotid Tumors Heinrich Iro, MD; Johannes Zenk, MD
HYPOTHESIS Extracapsular dissection is a safe and effective surgical technique in the management of benign parotid neoplasms.
Background A definition of extracapsular dissection (ED) is a necessary first step in assessing the procedure. It is a technique that involves the total removal of a benign tumor of the parotid gland surrounded by healthy parotid tissue without planned dissection of the main t r u n k o f t h e fa c i a l n e r ve. Branches of the nerve can be identified during the proceInvited Commentary page 770 dure; therefore, nerve stimulation and monitoring are essential for orientation. Extracapsular dissection should not be confused with enucleation or nodulectomy. Enucleation is a procedure that involves opening of the capsule with intracapsular removal of the tumor while leaving the capsule in place. In nodulectomy the tumor is excised directly at the tumor capsule without any of the surrounding tissue.1 During the past century these surgical techniques were abandoned in view of the high rate of recurrence of the tumors and justifiably led to the establishment of formal parotidectomy, which significantly reduced the recurrence of benign parotid tumors, particularly pleomorphic adenomas (PAs). The main difference between ED and all other forms of parotidectomy is that it does not include exposure of the facial nerve at the main trunk to achieve tumor removal. The debate continues as to whether ED is justifiable as a lessinvasive surgical treatment. To answer this question, the following basic criteria should be met to ensure selection of the optimum surgical method: 1. Safe tumor resection with equivalent recurrence rate; 2. Lower or equivalent complication rates; 3. Safe, reliable resection in case of recurrence; and 4. Good cosmetic results.
Pro The most frequently occurring benign tumor of the parotid gland is the PA, followed by the Warthin tumor. Therefore, it makes sense to give primary consideration to the PA in the present discussion. The so-called “bare area” on the tumor can serve as a macroscopic criterion for inadequate resection. This is unavoidable in cases where the tumor is in contact with the facial nerve, musculature, vessels, auditory meatus, or mandibular joint. No one would want to sacrifice these structures to maintain a safe margin during resection of a benign tumor. This is a well-known problem; as described by Donovan and Conley2 in 1984, such a bare area is observed in 61% of PA resection surfaces when a formal parotidectomy is carried out. 768
In histologic terms, pseudopodia and tumor satellites are considered to be responsible for potential recurrence of PAs. Whether the latter are artifacts or are present with some PAs has not been conclusively clarified. However, in 2003, Ghosh et al3 stated that a thin connective tissue layer around the tumor is sufficient to ensure safe tumor resection and minimum re- Johannes Zenk, MD currence rates. This contradicts authors who today still insist on a safety margin of at least 2 cm for PAs.4 Riad et al5 demonstrated in one of the few prospective studies that such a safety margin was feasible in fewer than 4% of all PAs and that resection directly adjacent to the capsule was unavoidable in 30%. Based on the recurrence rates reported in the literature,6 there is no significant difference among the various resec- Heinrich Iro, MD tion techniques, including ED. Factors such as tumor size or intraoperative tumor spillage show greater significance. In a controlled patient contingent of 67 PAs dissected with ED, there have been no recurrences over a mean follow-up monitoring period of 7.4 years.7 In a recent meta-analysis, Albergotti et al8 reported no significant difference when comparing ED with lateral parotidectomy. Therefore, the factors of safe tumor removal and rate of recurrence do not weigh against ED. Complications of parotid surgery include, above all, temporary and permanent paresis of the facial nerve, Frey syndrome, and dysesthesias of the greater auricular nerve. Generally speaking, the frequency of complications increases with the degree of invasiveness of the intervention. In a study9 including 377 EDs, the temporary paresis rate was 6.1%, with permanent pareses in 2.1% of the cases; 1.8% of the patients showed a House-Brackmann score of II and only 0.3% of the patients had a score of III. Similar results were obtained by McGurk et al.10 In assessing this complication, the metaanalysis by Albergotti et al8 demonstrated that the frequency of temporary paresis and Frey syndrome was significantly lower with ED than with lateral parotidectomy. The rate of permanent facial paresis was equivalent; however, the House-Brackmann score was not reported. Because most of the parotid tissue remains in place in ED, the postoperative cosmetic findings are essentially the same as on the healthy side. This information reflects clinical experience not currently supported by systematic studies. Therefore, both complication rates and postoperative cosmetic results appear to favor ED.
JAMA Otolaryngology–Head & Neck Surgery August 2014 Volume 140, Number 8
Copyright 2014 American Medical Association. All rights reserved.
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Clinical Challenges in Otolaryngology Clinical Review & Education
One aspect of the discussion on the use of ED that is often ignored is the patient’s risk if there is a recurrence. Every surgeon who has performed an operation for recurrent tumor after lateral or total parotidectomy knows how challenging this can be. A second recurrence often is inevitable. Because ED does not primarily expose the facial nerve, the second operation poses a risk to the nerve equivalent to that of the initial operation. Owing to the reduced level of exposure of the surrounding structures, increased dissemination of the PA is not expected. Therefore, there would likely be an advantage for the patient who requires a second operation for recurrence after ED compared with a patient who needs a second operation after a formal parotidectomy.
Con The facts reported in the literature5-10 shed more positive than negative light on ED. However, the procedure must be used where properly indicated, with the proper technique. The application of ED for deep lobe or malignant tumors or performance without proper training and nerve monitoring may increase the risk of recurrence or complications to unacceptable levels. An ideal precondition for ED is the presence of a singular benign tumor located in the caudal portion of the gland. With a surgeon’s increasing levels of practical experience, superficial mobile tumors in the lateral gland segment can also be removed safely with ED. Appropriate preoperative imaging (ulARTICLE INFORMATION Author Affiliations: Department of Otorhinolaryngology, Head and Neck Surgery, University of Erlangen–Nuremberg, Erlangen, Germany (Iro); Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum Augsburg, Augsburg, Germany (Zenk). Corresponding Author: Johannes Zenk, MD, Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum Augsburg, Sauerbruchstrasse 6, D-86179 Augsburg, Germany ([email protected]). Section Editor: Marion Boyd Gillespie, MD, MSc. Published Online: July 17, 2014. doi:10.1001/jamaoto.2014.1218. Conflict of Interest Disclosures: None reported. REFERENCES 1. Zbären P, Vander Poorten V, Witt RL, et al. Pleomorphic adenoma of the parotid: formal
jamaotolaryngology.com
trasonography, magnetic resonance imaging, and computed tomography) and the use of intraoperative nerve monitoring and stimulation are imperative for ED. Preparation outside of the tumor capsule within a healthy tissue margin and cautious handling of the tumor to avoid rupture are basic principles. It may occasionally become necessary to deviate from a planned ED and convert to a more extensive procedure intraoperatively. Familiarity with traditional parotid surgery is therefore important. One concern is that ED might result in neglect of traditional surgery. At our center we perform a total of 200 procedures annually on benign tumors, using ED for approximately 60% of the operations. Thus, enough standard procedures are done to facilitate training of residents in all of the relevant parotidectomy techniques. Even centers where fewer procedures are performed offer sufficient opportunities for teaching surgical trainees. With an eye to the future, we believe that it makes sense to teach less-invasive techniques which, as mentioned above, tend to benefit the patients.
Bottom Line In summary, ED represents a procedure that makes good sense and is less traumatic from the patient’s point of view in cases of benign parotid tumors. It is important to obtain further prospective data and to use ED along with all other parotid procedures responsibly in terms of indication and implementation.
parotidectomy or limited surgery? Am J Surg. 2013; 205(1):109-118.
treatment of parotid pleomorphic adenomas. Br J Surg. 1996;83(12):1747-1749.
2. Donovan DT, Conley JJ. Capsular significance in parotid tumor surgery: reality and myths of lateral lobectomy. Laryngoscope. 1984;94(3):324-329.
7. Iro H, Zenk J, Koch M, Klintworth N. Follow-up of parotid pleomorphic adenomas treated by extracapsular dissection. Head Neck. 2013;35(6): 788-793.
3. Ghosh S, Panarese A, Bull PD, Lee JA. Marginally excised parotid pleomorphic salivary adenomas: risk factors for recurrence and management: a 12.5-year mean follow-up study of histologically marginal excisions. Clin Otolaryngol Allied Sci. 2003;28(3):262-266. 4. Makeieff M, Pelliccia P, Letois F, et al. Recurrent pleomorphic adenoma: results of surgical treatment. Ann Surg Oncol. 2010;17(12):3308-3313. 5. Riad MA, Abdel-Rahman H, Ezzat WF, Adly A, Dessouky O, Shehata M. Variables related to recurrence of pleomorphic adenomas: outcome of parotid surgery in 182 cases. Laryngoscope. 2011;121 (7):1467-1472.
8. Albergotti WG, Nguyen SA, Gillespie MB. In response to extracapsular dissection for benign parotid tumors: a meta-analysis. Laryngoscope. 2014;124(2):55. doi:10.1002/lary.23969. 9. Klintworth N, Zenk J, Koch M, Iro H. Postoperative complications after extracapsular dissection of benign parotid lesions with particular reference to facial nerve function. Laryngoscope. 2010;120(3):484-490. 10. McGurk M, Thomas BL, Renehan AG. Extracapsular dissection for clinically benign parotid lumps: reduced morbidity without oncological compromise. Br J Cancer. 2003;89(9):1610-1613.
6. McGurk M, Renehan A, Gleave EN, Hancock BD. Clinical significance of the tumour capsule in the
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 California - San Diego User on 06/04/2015
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Clinical Challenges in Otolaryngology
Role of Extracapsular Dissection in Surgical Management of Benign Parotid Tumors Heinrich Iro, MD; Johannes Zenk, MD
HYPOTHESIS Extracapsular dissection is a safe and effective surgical technique in the management of benign parotid neoplasms.
Background A definition of extracapsular dissection (ED) is a necessary first step in assessing the procedure. It is a technique that involves the total removal of a benign tumor of the parotid gland surrounded by healthy parotid tissue without planned dissection of the main t r u n k o f t h e fa c i a l n e r ve. Branches of the nerve can be identified during the proceInvited Commentary page 770 dure; therefore, nerve stimulation and monitoring are essential for orientation. Extracapsular dissection should not be confused with enucleation or nodulectomy. Enucleation is a procedure that involves opening of the capsule with intracapsular removal of the tumor while leaving the capsule in place. In nodulectomy the tumor is excised directly at the tumor capsule without any of the surrounding tissue.1 During the past century these surgical techniques were abandoned in view of the high rate of recurrence of the tumors and justifiably led to the establishment of formal parotidectomy, which significantly reduced the recurrence of benign parotid tumors, particularly pleomorphic adenomas (PAs). The main difference between ED and all other forms of parotidectomy is that it does not include exposure of the facial nerve at the main trunk to achieve tumor removal. The debate continues as to whether ED is justifiable as a lessinvasive surgical treatment. To answer this question, the following basic criteria should be met to ensure selection of the optimum surgical method: 1. Safe tumor resection with equivalent recurrence rate; 2. Lower or equivalent complication rates; 3. Safe, reliable resection in case of recurrence; and 4. Good cosmetic results.
Pro The most frequently occurring benign tumor of the parotid gland is the PA, followed by the Warthin tumor. Therefore, it makes sense to give primary consideration to the PA in the present discussion. The so-called “bare area” on the tumor can serve as a macroscopic criterion for inadequate resection. This is unavoidable in cases where the tumor is in contact with the facial nerve, musculature, vessels, auditory meatus, or mandibular joint. No one would want to sacrifice these structures to maintain a safe margin during resection of a benign tumor. This is a well-known problem; as described by Donovan and Conley2 in 1984, such a bare area is observed in 61% of PA resection surfaces when a formal parotidectomy is carried out. 768
In histologic terms, pseudopodia and tumor satellites are considered to be responsible for potential recurrence of PAs. Whether the latter are artifacts or are present with some PAs has not been conclusively clarified. However, in 2003, Ghosh et al3 stated that a thin connective tissue layer around the tumor is sufficient to ensure safe tumor resection and minimum re- Johannes Zenk, MD currence rates. This contradicts authors who today still insist on a safety margin of at least 2 cm for PAs.4 Riad et al5 demonstrated in one of the few prospective studies that such a safety margin was feasible in fewer than 4% of all PAs and that resection directly adjacent to the capsule was unavoidable in 30%. Based on the recurrence rates reported in the literature,6 there is no significant difference among the various resec- Heinrich Iro, MD tion techniques, including ED. Factors such as tumor size or intraoperative tumor spillage show greater significance. In a controlled patient contingent of 67 PAs dissected with ED, there have been no recurrences over a mean follow-up monitoring period of 7.4 years.7 In a recent meta-analysis, Albergotti et al8 reported no significant difference when comparing ED with lateral parotidectomy. Therefore, the factors of safe tumor removal and rate of recurrence do not weigh against ED. Complications of parotid surgery include, above all, temporary and permanent paresis of the facial nerve, Frey syndrome, and dysesthesias of the greater auricular nerve. Generally speaking, the frequency of complications increases with the degree of invasiveness of the intervention. In a study9 including 377 EDs, the temporary paresis rate was 6.1%, with permanent pareses in 2.1% of the cases; 1.8% of the patients showed a House-Brackmann score of II and only 0.3% of the patients had a score of III. Similar results were obtained by McGurk et al.10 In assessing this complication, the metaanalysis by Albergotti et al8 demonstrated that the frequency of temporary paresis and Frey syndrome was significantly lower with ED than with lateral parotidectomy. The rate of permanent facial paresis was equivalent; however, the House-Brackmann score was not reported. Because most of the parotid tissue remains in place in ED, the postoperative cosmetic findings are essentially the same as on the healthy side. This information reflects clinical experience not currently supported by systematic studies. Therefore, both complication rates and postoperative cosmetic results appear to favor ED.
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 California - San Diego User on 06/04/2015
jamaotolaryngology.com
Clinical Challenges in Otolaryngology Clinical Review & Education
One aspect of the discussion on the use of ED that is often ignored is the patient’s risk if there is a recurrence. Every surgeon who has performed an operation for recurrent tumor after lateral or total parotidectomy knows how challenging this can be. A second recurrence often is inevitable. Because ED does not primarily expose the facial nerve, the second operation poses a risk to the nerve equivalent to that of the initial operation. Owing to the reduced level of exposure of the surrounding structures, increased dissemination of the PA is not expected. Therefore, there would likely be an advantage for the patient who requires a second operation for recurrence after ED compared with a patient who needs a second operation after a formal parotidectomy.
Con The facts reported in the literature5-10 shed more positive than negative light on ED. However, the procedure must be used where properly indicated, with the proper technique. The application of ED for deep lobe or malignant tumors or performance without proper training and nerve monitoring may increase the risk of recurrence or complications to unacceptable levels. An ideal precondition for ED is the presence of a singular benign tumor located in the caudal portion of the gland. With a surgeon’s increasing levels of practical experience, superficial mobile tumors in the lateral gland segment can also be removed safely with ED. Appropriate preoperative imaging (ulARTICLE INFORMATION Author Affiliations: Department of Otorhinolaryngology, Head and Neck Surgery, University of Erlangen–Nuremberg, Erlangen, Germany (Iro); Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum Augsburg, Augsburg, Germany (Zenk). Corresponding Author: Johannes Zenk, MD, Department of Otorhinolaryngology, Head and Neck Surgery, Klinikum Augsburg, Sauerbruchstrasse 6, D-86179 Augsburg, Germany ([email protected]). Section Editor: Marion Boyd Gillespie, MD, MSc. Published Online: July 17, 2014. doi:10.1001/jamaoto.2014.1218. Conflict of Interest Disclosures: None reported. REFERENCES 1. Zbären P, Vander Poorten V, Witt RL, et al. Pleomorphic adenoma of the parotid: formal
jamaotolaryngology.com
trasonography, magnetic resonance imaging, and computed tomography) and the use of intraoperative nerve monitoring and stimulation are imperative for ED. Preparation outside of the tumor capsule within a healthy tissue margin and cautious handling of the tumor to avoid rupture are basic principles. It may occasionally become necessary to deviate from a planned ED and convert to a more extensive procedure intraoperatively. Familiarity with traditional parotid surgery is therefore important. One concern is that ED might result in neglect of traditional surgery. At our center we perform a total of 200 procedures annually on benign tumors, using ED for approximately 60% of the operations. Thus, enough standard procedures are done to facilitate training of residents in all of the relevant parotidectomy techniques. Even centers where fewer procedures are performed offer sufficient opportunities for teaching surgical trainees. With an eye to the future, we believe that it makes sense to teach less-invasive techniques which, as mentioned above, tend to benefit the patients.
Bottom Line In summary, ED represents a procedure that makes good sense and is less traumatic from the patient’s point of view in cases of benign parotid tumors. It is important to obtain further prospective data and to use ED along with all other parotid procedures responsibly in terms of indication and implementation.
parotidectomy or limited surgery? Am J Surg. 2013; 205(1):109-118.
treatment of parotid pleomorphic adenomas. Br J Surg. 1996;83(12):1747-1749.
2. Donovan DT, Conley JJ. Capsular significance in parotid tumor surgery: reality and myths of lateral lobectomy. Laryngoscope. 1984;94(3):324-329.
7. Iro H, Zenk J, Koch M, Klintworth N. Follow-up of parotid pleomorphic adenomas treated by extracapsular dissection. Head Neck. 2013;35(6): 788-793.
3. Ghosh S, Panarese A, Bull PD, Lee JA. Marginally excised parotid pleomorphic salivary adenomas: risk factors for recurrence and management: a 12.5-year mean follow-up study of histologically marginal excisions. Clin Otolaryngol Allied Sci. 2003;28(3):262-266. 4. Makeieff M, Pelliccia P, Letois F, et al. Recurrent pleomorphic adenoma: results of surgical treatment. Ann Surg Oncol. 2010;17(12):3308-3313. 5. Riad MA, Abdel-Rahman H, Ezzat WF, Adly A, Dessouky O, Shehata M. Variables related to recurrence of pleomorphic adenomas: outcome of parotid surgery in 182 cases. Laryngoscope. 2011;121 (7):1467-1472.
8. Albergotti WG, Nguyen SA, Gillespie MB. In response to extracapsular dissection for benign parotid tumors: a meta-analysis. Laryngoscope. 2014;124(2):55. doi:10.1002/lary.23969. 9. Klintworth N, Zenk J, Koch M, Iro H. Postoperative complications after extracapsular dissection of benign parotid lesions with particular reference to facial nerve function. Laryngoscope. 2010;120(3):484-490. 10. McGurk M, Thomas BL, Renehan AG. Extracapsular dissection for clinically benign parotid lumps: reduced morbidity without oncological compromise. Br J Cancer. 2003;89(9):1610-1613.
6. McGurk M, Renehan A, Gleave EN, Hancock BD. Clinical significance of the tumour capsule in the
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 California - San Diego User on 06/04/2015
769
