- Email: [email protected]
Anterior Versus Posterior Routes of Reconstruction After Esophagectomy: A Comparative Anatomic Study
GENERAL THORACIC
Anterior Versus Posterior Routes of Reconstruction After Esophagectomy: A Comparative Anatomic Study Haiquan Chen, MD, FCCP, Jiade J. Lu, MD, MBA, Jianhua Zhou, MD, Xian Zhou, MD, Xiaoyang Luo, MD, Quan Liu, MD, and John Tam, MD Departments of Cardiothoracic Surgery and Radiology, The Cancer Hospital of Fudan University, Shanghai, China; and The Cancer Institute, National Healthcare Group, Singapore, Singapore
Background. A gastric conduit is commonly used to reconstruct the alimentary tract after esophagectomy for esophageal cancer. The choice of anterior versus posterior route for reconstruction is debatable, and longer distance of the reconstructed routes may be associated with higher tension exerted on the transposed stomach. The aim of this study is to evaluate the length of both the anterior and posterior routes in a group of patients measured intraoperatively during esophagectomy for esophageal cancer. Methods. Sixty consecutive and nonselected patients with thoracic esophageal cancer were accrued in this prospective study. Measurements of the anterior (retro-
sternal) and posterior routes were performed after esophagectomy but before reconstruction with gastric conduit, from the cricoid cartilage to the pyloric ring. Results. The lengths of the anterior and posterior routes were 32.68 ⴞ 2.67 cm and 35.48 ⴞ 2.93 cm, respectively (p < 0.001). The anterior route is significantly shorter than the posterior route. Conclusions. The anterior (retrosternal) route is the shorter passage for the reconstruction of the alimentary tract using the stomach after esophagectomy.
E
tion was debatable [5–7]. In addition, comparison of the length of the two routes was never performed in live patients. The objective of this study is to compare the length of the different routes during esophagectomy to determine which approach is more conducive for surgical reconstruction.
sophagectomy is the mainstay treatment for esophageal cancer. Reconstruction of the alimentary tract is essential after esophagectomy, and the resected esophagus is most commonly substituted by the stomach [1]. Reconstruction in this circumstance is either achieved using the anterior (retrosternal) route (AR) or the posterior (prevertebral) route (PR) through the mediastinum [2]. Although both approaches have been widely used, it is debatable which one is more advantageous. Whereas AR places the gastric conduit outside the tumor bed so that digestive function will not be interfered with by local recurrence, and delivery of adjuvant radiation therapy is less complicated if needed, PR is preferred by many surgeons with a perception that it is associated with less probability of postoperative complications [2, 3]. However, these perceptions have not been supported by large-scale prospective randomized studies, and metaanalysis of randomized controlled trials on this topic revealed that both approaches yielded similar outcomes [4]. One of the commonly cited reasons for using PR is that the prevertebral route is relatively shorter than the retrosternal route, which may translate to reduced tension for the anastomosis. Previously reported postmortem analyses showed that AR is approximately 2 to 3 cm longer than PR; however, the reference points used in those studies varied, and the rationale of reference point selec-
Accepted for publication Nov 10, 2008. Address correspondence to Dr Chen, 270# Dong’an Rd, Shanghai, 200032, China; e-mail: [email protected].
© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2009;87:400 – 4) © 2009 by The Society of Thoracic Surgeons
Patients and Methods Between December 2005 and October 2007, a total of 60 consecutive and nonselected patients who were diagnosed with thoracic squamous cell carcinoma of the esophagus and planned to receive esophagectomy were accrued into this institutional review board–approved prospective study. Written consents were obtained from all participating patients before their surgery. Pretreatment evaluation included a complete history and physical examination, chest roentgenogram, computed tomography of the chest and upper abdomen, complete blood counts, serum electrolyte tests, and liver, pulmonary, and kidney function tests, as well as triple endoscopy with biopsy of the esophageal lesion for pathologic diagnosis. Esophagectomy with lymphadenectomy was routinely performed with cervical esophagogastric anastomosis. General anesthesia was administered, and the patient was positioned in the left lateral decubitus position. A standard right muscle-sparing posterolateral thoracotomy was performed through the fourth or fifth intercostal space. The right hemithorax was carefully explored to 0003-4975/09/$36.00 doi:10.1016/j.athoracsur.2008.11.016
CHEN ET AL ROUTES OF RECONSTRUCTION AFTER ESOPHAGECTOMY
401
Table 1. The Mean Distances of AR and PRa Variable Mean distance (cm) a
PR ⬎ AR;
rule out any surgical contraindications before proceeding with the resection. The intrathoracic esophagus was mobilized and thoracic lymphadenectomy was performed; the esophageal carcinoma was then resected. A
PR
32.7 ⫾ 2.7
35.5 ⫾ 2.9
p ⬍ 0.001.
AR ⫽ anterior route;
Fig 1. The cervical incision showing the esophagus (A), the white tape positioned in the prevertebral route (B); and the blue inelastic polyethylene tape passed through the retrosternal tunnel (C).
AR
PR ⫽ posterior route.
white inelastic polyethylene tape was attached to each end of the esophagus. The patient was then placed in the supine position, and a midline laparotomy incision was made. The abdominal cavity was explored to rule out intraabdominal metastasis. Gastric mobilization was performed, and a gastric tube was fashioned as the conduit for esophageal replacement. The Kocher maneuver was not routinely performed as part of this operation. A space within the retrosternal mediastinum was created using a combination of blunt and sharp dissection. Before the neoesophagus was then tunneled through the retrosternal route, a blue inelastic polyethylene tape passed through the retrosternal tunnel. An oblique cervical incision was made anterior to the left sternocleidomastoid muscle. The space between the carotid sheath and the trachea was dissected, and the cervical esophagus was identified. A single-layer handsewn cervical esophagogastric anastomosis was then performed at the level of the cricoid cartilage. Careful measurements of the length of the two routes were made after the esophagus was removed but before alimentary tract reconstruction. Patients were placed in the supine position with the neck slightly extended at the time of the measurements. The cricoid cartilage was used as the proximal reference point and the pyloric ring was used as the distal reference point. The white tape was positioned in the prevertebral route, and the blue inelastic polyethylene tape was used for the retrosternal route. The two tapes were carefully aligned at the two references points, and the distances of both routes were measured (Figs 1, 2).
Results
Fig 2. The abdominal incision showing the pylorus (A), the blue inelastic polyethylene tape passed through the retrosternal tunnel (B), and the white tape positioned in the prevertebral route (C).
The median age of all patients was 59.9 years (range, 43 to 79 years). Fifty patients were Chinese men and 10 were women. All patients were diagnosed with esophageal squamous cell carcinoma in the thoracic esophagus. The number of lesions located in the upper, mid, and lower thoracic esophagus were 15, 33, and 12, respectively. All patients received esophagectomy as well as reconstruction using the gastric conduit through AR as planned. The mean distances of AR and PR were 32.7 ⫾ 2.7 cm and 35.5 ⫾ 2.9 cm, respectively. Anterior route is found to be significantly shorter than PR (p ⬍ 0.001). The distances of the two routes are compared in Table 1.
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Table 2. Studies on the Distance of the Anterior and Posterior Routes of Reconstruction Orringer and Sloan [5]
Variable
Ngan and Wong [6]
Coral et al. [7]
Object Number of patients Proximal reference point Distal reference point
cadaver 10 unknown unknown
cadaver
cadaver
20 cricoid cartilage celiac axis
50 cricoid cartilage celiac axis
Result
AR ⬎ PR
AR is 1.9 cm longer than PR
AR is 5.31 cm longer than PR
AR ⫽ anterior route;
Current Study
gastroduodenal artery AR is 2.51 cm longer than PR
Patient in operation 60 cricoid cartilage pyloric ring AR is 2.8 cm shorter than PR
PR ⫽ posterior route.
Comment Esophagectomy followed by reconstruction of the alimentary tract is the mainstay treatment for early stage resectable esophageal cancers. Alimentary tract reconstruction is commonly achieved using a gastric conduit, and can be positioned either through AR or PR [2]. Although various reasons have been cited for selection of the routes, it seems that the choices are influenced more by the preferences and experience of surgeons than by best evidence, as the data available are scarce and controversial. One of the reasons for choosing the posterior route for reconstruction is that it might be shorter, thus associated with reduced tension on the gastric conduit. However, the length of AR and PR has only been measured in limited numbers of cadavers in reported series, and the rationale of the selection of the proximal and distal reference points of measurements was debatable. Understanding the anatomic details with clinical relevance is important for planning treatment strategy for esophageal cancer. In the current study, we compared the lengths of both AR and PR of the gastric conduit using reference points that are more surgically relevant, and discovered that AR is significantly shorter than PR for reconstruction of the alimentary tract after esophagectomy. Specifically, the lengths of AR and PR were 32.7 ⫾ 2.7 cm and 35.5 ⫾ 2.9 cm, respectively (p ⬍ 0.001). The posterior route is preferred by many surgeons because of the perception that it might be associated with fewer complications [2, 3], possibly because of a shorter distance with less anastomotic tension [6, 7]. However, this finding has not been supported by large-scale randomized studies, and a meta-analysis reported by Urschel and colleagues [4] revealed that the choice of reconstruction routes is not significantly associated with the incidences of postoperative morbidities and mortalities. As part of the integrated treatment of esophageal cancer, reconstruction after esophagectomy should be planned with the entire treatment strategy in mind. One of the most important considerations in the management of esophageal cancer, particularly for patients with locally advanced disease, is the utility of neoadjuvant or adjuvant chemotherapy and radiotherapy. Neoadjuvant concurrent chemoradiation has been shown to improve treatment outcome for locally advanced esophageal can-
cer [8, 9]. Despite its efficacy, neoadjuvant or adjuvant chemoradiation is usually associated with substantial side effects and complications. Inflammation and fibrosis of adjacent soft tissues induced by combined chemoradiation will not only complicate surgical maneuvering during esophagectomy but will also adversely affect the postoperative recovery, respiratory capacity, and the functioning of the reconstructed alimentary tract, as well as increasing perioperative morbidity and mortality [10, 11]. In addition, local or regional recurrence is the most common form of treatment failure in patients with locally advanced esophageal cancer after definitive treatment [12]; thus, it is important to consider the possibility that recurrent tumors in the posterior mediastinum may cause obstruction and dysfunction of the gastric conduit when selecting the reconstruction route. With our current finding that AR is significantly shorter than PR, and the prevailing use of trimodality treatment for esophageal cancer in consideration, reconstruction by means of AR after esophagectomy should be considered as the preferable route if there are no other contraindications. The distances of the various routes for alimentary tract reconstruction were addressed previously and most of the studies revealed that the route through the anterior mediastinum is longer than the posterior route. Orringer and Sloan [5] studied 10 cadavers and discovered that the subcutaneous route is 2 to 3 cm longer than the posterior route. They postulated that the length of AR (retrosternal route) would also be longer, as it lies between the lengths of the subcutaneous and the posterior routes. It is important to note that the reference points used for measuring the two routes were not clearly stated in the report. Ngan and Wong [6] measured the distances from the cricoid cartilage to the celiac axis, and reported that AR is 1.9 cm longer than PR after studying 20 cadavers of Asian origin. Similar conclusions were found by Coral and associates [7] using cadavers of African American and Brazilian origins, with the celiac axis and gastroduodenal artery used as the distal reference points. The above-mentioned results seemed to differ substantially from our current findings (Table 2). We contribute these discrepancies to two major reasons. First, although all trials used the cricoid cartilage as the proximal reference point of measurement, the distal reference points used in the previous reports are different from the one we
used. In previously published trials, celiac axis and gastroduodenal artery were used instead. Because the celiac axis is located in the retroperitoneal space, its distance to the cricoid cartilage would be shorter if measured through the posterior mediastinum, as the passage is relatively straight compared with the more tortuous anterior route. However, this direct distance is not clinically relevant when the stomach is used for reconstruction without the Kocher maneuver. Similarly, although the gastroduodenal artery may serve as a fixed reference point to measure the anatomic distance of anterior and posterior mediastinum, it is also not surgically relevant for postesophagectomy reconstruction using the stomach. In the current study, the Kocher maneuver was not performed as we found mobilization of the duodenum was not necessary if the anterior route is used for reconstruction; thus, an unnecessary surgical procedure can be avoided. Therefore, the pyloric ring was chosen as a superior distal reference point because of its clinical relevance. The duodenum is fixed in the retroperitoneal position without performing the Kocher maneuver, and the pyloric ring is essentially fixed in position by the duodenum. Tension to the gastric conduit is present at the pyloric ring distally and the cervical anastomosis proximally. Therefore, the length between the pylorus and the cricoid cartilage is much more representative of the actual distance used for reconstruction. The finding of AR being the shorter route can be
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further explained using our knowledge of gross anatomy. As the pyloric ring is situated more anteriorly in the normal anatomic position (Fig 3), it is clear that using AR (retrosternal route) for transposing the stomach while the duodenum is fixed in position should be more direct and straight. Another possible explanation for the discrepancies between our results and the previous reports may be the different subjects used for measurements. Measurements comparing the two routes were performed only on cadavers in all previous trials, whereas the measurements in our study are performed on patients during esophagectomy before reconstruction. Postmortem changes and procedures for maintaining the cadavers may significantly change the texture of certain human tissues such as the lung. The anatomic structure of a cadaver may only approximate that of a living human body, especially when the magnitude of the differences of the two routes ranges at 2 to 3 cm. Therefore, measurement results obtained during surgery are more accurate as the body and the organs surrounding the reconstruction routes are under normal physiologic conditions. Although we discovered that the anterior route is shorter for postesophagectomy reconstruction using the stomach, whether this route is associated with fewer postoperative complications remains unanswered. Urschel and colleagues [4] reported that no significant differences could be found in the postoperative morbidity and mortality comparing the two procedures in their meta-analysis; however, all studies included in that analysis were completed before the trimodality era, and neoadjuvant treatments were not used for most patients. As neoadjuvant chemoradiation is currently considered part of the standard treatment for locally advanced esophageal cancer, avoiding the tumor bed within the radiotherapy field during reconstruction may be crucial for reducing posttreatment complications of the gastric conduit. However, this probability cannot be sufficiently addressed without a well-designed prospective clinical trial. Esophageal cancer is relatively common in Asia, and most of the cases are treated in tertiary-care hospitals specializing in cancer management. A multicenter randomized clinical trial is currently under development to study the outcome, complications, and quality of life associated with the routes of alimentary tract reconstruction in patients with esophageal carcinoma undergoing trimodality therapy.
References
Fig 3. The pyloric ring is situated more anteriorly in the normal anatomic position.
1. Akiyama H, Miyazono H, Tsurumaru M, et al. Use of the stomach as an esophageal substitute. Ann Surg 1978;188: 606 –10. 2. Bartels H, Thorban S, Siewert JR. Anterior versus posterior reconstruction after transhiatal esophagectomy: a randomized controlled trial. Br J Surg 1993;80:1141– 4. 3. Gawad KA, Hosch SB, Bumann D, et al. How important is the route of reconstruction after esophagectomy: a prospective randomized study. Am J Gastroenterol 1999;94:1490 –9. 4. Urschel JD, Urschel DM, Miller JD, et al. A meta-analysis of randomized controlled trials of route of reconstruction after esophagectomy for cancer. Am J Surg 2001;182:470 –5.
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5. Orringer MB, Sloan H. Substernal gastric bypass of the excluded thoracic esophagus for palliation of esophageal carcinoma. J Thorac Cardiovasc Surg 1975;70: 836 –51. 6. Ngan SY, Wong J. Lengths of different routes for esophageal replacement. J Thorac Cardiovasc Surg 1986;91:790 –2. 7. Coral RP, Constant-Neto M, Silva IS, et al. Comparative anatomical study of the anterior and posterior mediastinum as access routes after esophagectomy. Dis Esophagus 2003; 16:236 – 8. 8. Gebski V, Burmeister B, Smithers BM, et al. Survival benefits from neoadjuvant chemoradiotherapy or chemotherapy in oesophageal carcinoma: a meta-analysis. Lancet Oncol 2007; 8:226 –34.
Ann Thorac Surg 2009;87:400 – 4
9. Tepper J, Krasna M, Niedzwiecki D, et al. Superiority of trimodality therapy to surgery alone in esophageal cancer: results of CALGB 9781. J Clin Oncol 2006;24(Suppl 1):4012 (abstract). 10. Lecleire S, Di Fiore F, Ben-Soussan E, et al. Prior chemoradiotherapy is associated with a higher life-threatening complication rate after palliative insertion of metal stents in patients with oesophageal cancer. Aliment Pharmacol Ther 2006;23:1693–702. 11. Makary MA, Kiernan PD, Sheridan MJ, et al. Multimodality treatment for esophageal cancer. The role of surgery and neoadjuvant therapy. Am Surg 2003;69:693–700. 12. Natsugoe S, Okumura H, Matsumoto M, et al. The role of salvage surgery for recurrence of esophageal squamous cell cancer. Eur J Surg Oncol 2006;32:544 –7.
Requirements for Maintenance of Certification in 2009 Diplomates of the American Board of Thoracic Surgery (ABTS) who plan to participate in the Maintenance of Certification (MOC) process which will begin in 2009 must hold an unrestricted medical license in the locale of their practice and privileges in a hospital accredited by the JCAHO (or other organization recognized by the ABTS). In addition, a valid ABTS certificate is an absolute requirement for entrance into the Maintenance of Certification process. If your certificate has expired, the only pathway for renewal of a certificate is to take and pass the Part I (written) and the Part II (oral) certifying examinations. The names of individuals who have not maintained their certificate will no longer be published in the American Board of Medical Specialties directories. Diplomates’ names will be published upon successful completion of the Maintenance of Certification process. The CME requirements are 30 Category I credits earned during each year prior to application. At least half of these CME hours need to be in the broad area of thoracic surgery. Category II credits are not allowed. Interested individuals should refer to the Booklet of Information for Maintenance of Certification for a complete description of acceptable CME credits. Diplomates in the Maintenance of Certification process will be required to complete all sections of the SESATS
© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
self-assessment examination. It is not necessary for Diplomates to purchase SESATS individually because it will be sent to them after their application has been approved. Diplomates may apply for Maintenance of Certification in the year their certificate expires, or if they wish to do so, they may apply up to two years before it expires. However, the new certificate will be dated 10 years from the date of expiration of their original certificate or most recent recertification certificate. In other words, going through the Maintenance of Certification process early does not alter the 10-year validation. Diplomates certified prior to 1976 (the year that time-limited certificates were initiated) are also required to participate in MOC if they wish to maintain valid certificates. The deadline for submission of application for the Maintenance of Certification is May 10 of each year. All ABTS diplomates will receive a letter from the Board outlining their individual timeline and MOC requirements. A brochure outlining the rules and requirements for Maintenance of Certification in thoracic surgery is available upon request from the American Board of Thoracic Surgery, 633 North St. Clair St, Suite 2320, Chicago, IL 60611; telephone (312) 202-5900; fax (312) 202-5960; e-mail: [email protected]. This booklet is also published on the website: www.abts.org.
Ann Thorac Surg 2009;87:404
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0003-4975/09/$36.00
Anterior Versus Posterior Routes of Reconstruction After Esophagectomy: A Comparative Anatomic Study Haiquan Chen, MD, FCCP, Jiade J. Lu, MD, MBA, Jianhua Zhou, MD, Xian Zhou, MD, Xiaoyang Luo, MD, Quan Liu, MD, and John Tam, MD Departments of Cardiothoracic Surgery and Radiology, The Cancer Hospital of Fudan University, Shanghai, China; and The Cancer Institute, National Healthcare Group, Singapore, Singapore
Background. A gastric conduit is commonly used to reconstruct the alimentary tract after esophagectomy for esophageal cancer. The choice of anterior versus posterior route for reconstruction is debatable, and longer distance of the reconstructed routes may be associated with higher tension exerted on the transposed stomach. The aim of this study is to evaluate the length of both the anterior and posterior routes in a group of patients measured intraoperatively during esophagectomy for esophageal cancer. Methods. Sixty consecutive and nonselected patients with thoracic esophageal cancer were accrued in this prospective study. Measurements of the anterior (retro-
sternal) and posterior routes were performed after esophagectomy but before reconstruction with gastric conduit, from the cricoid cartilage to the pyloric ring. Results. The lengths of the anterior and posterior routes were 32.68 ⴞ 2.67 cm and 35.48 ⴞ 2.93 cm, respectively (p < 0.001). The anterior route is significantly shorter than the posterior route. Conclusions. The anterior (retrosternal) route is the shorter passage for the reconstruction of the alimentary tract using the stomach after esophagectomy.
E
tion was debatable [5–7]. In addition, comparison of the length of the two routes was never performed in live patients. The objective of this study is to compare the length of the different routes during esophagectomy to determine which approach is more conducive for surgical reconstruction.
sophagectomy is the mainstay treatment for esophageal cancer. Reconstruction of the alimentary tract is essential after esophagectomy, and the resected esophagus is most commonly substituted by the stomach [1]. Reconstruction in this circumstance is either achieved using the anterior (retrosternal) route (AR) or the posterior (prevertebral) route (PR) through the mediastinum [2]. Although both approaches have been widely used, it is debatable which one is more advantageous. Whereas AR places the gastric conduit outside the tumor bed so that digestive function will not be interfered with by local recurrence, and delivery of adjuvant radiation therapy is less complicated if needed, PR is preferred by many surgeons with a perception that it is associated with less probability of postoperative complications [2, 3]. However, these perceptions have not been supported by large-scale prospective randomized studies, and metaanalysis of randomized controlled trials on this topic revealed that both approaches yielded similar outcomes [4]. One of the commonly cited reasons for using PR is that the prevertebral route is relatively shorter than the retrosternal route, which may translate to reduced tension for the anastomosis. Previously reported postmortem analyses showed that AR is approximately 2 to 3 cm longer than PR; however, the reference points used in those studies varied, and the rationale of reference point selec-
Accepted for publication Nov 10, 2008. Address correspondence to Dr Chen, 270# Dong’an Rd, Shanghai, 200032, China; e-mail: [email protected].
© 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2009;87:400 – 4) © 2009 by The Society of Thoracic Surgeons
Patients and Methods Between December 2005 and October 2007, a total of 60 consecutive and nonselected patients who were diagnosed with thoracic squamous cell carcinoma of the esophagus and planned to receive esophagectomy were accrued into this institutional review board–approved prospective study. Written consents were obtained from all participating patients before their surgery. Pretreatment evaluation included a complete history and physical examination, chest roentgenogram, computed tomography of the chest and upper abdomen, complete blood counts, serum electrolyte tests, and liver, pulmonary, and kidney function tests, as well as triple endoscopy with biopsy of the esophageal lesion for pathologic diagnosis. Esophagectomy with lymphadenectomy was routinely performed with cervical esophagogastric anastomosis. General anesthesia was administered, and the patient was positioned in the left lateral decubitus position. A standard right muscle-sparing posterolateral thoracotomy was performed through the fourth or fifth intercostal space. The right hemithorax was carefully explored to 0003-4975/09/$36.00 doi:10.1016/j.athoracsur.2008.11.016
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Table 1. The Mean Distances of AR and PRa Variable Mean distance (cm) a
PR ⬎ AR;
rule out any surgical contraindications before proceeding with the resection. The intrathoracic esophagus was mobilized and thoracic lymphadenectomy was performed; the esophageal carcinoma was then resected. A
PR
32.7 ⫾ 2.7
35.5 ⫾ 2.9
p ⬍ 0.001.
AR ⫽ anterior route;
Fig 1. The cervical incision showing the esophagus (A), the white tape positioned in the prevertebral route (B); and the blue inelastic polyethylene tape passed through the retrosternal tunnel (C).
AR
PR ⫽ posterior route.
white inelastic polyethylene tape was attached to each end of the esophagus. The patient was then placed in the supine position, and a midline laparotomy incision was made. The abdominal cavity was explored to rule out intraabdominal metastasis. Gastric mobilization was performed, and a gastric tube was fashioned as the conduit for esophageal replacement. The Kocher maneuver was not routinely performed as part of this operation. A space within the retrosternal mediastinum was created using a combination of blunt and sharp dissection. Before the neoesophagus was then tunneled through the retrosternal route, a blue inelastic polyethylene tape passed through the retrosternal tunnel. An oblique cervical incision was made anterior to the left sternocleidomastoid muscle. The space between the carotid sheath and the trachea was dissected, and the cervical esophagus was identified. A single-layer handsewn cervical esophagogastric anastomosis was then performed at the level of the cricoid cartilage. Careful measurements of the length of the two routes were made after the esophagus was removed but before alimentary tract reconstruction. Patients were placed in the supine position with the neck slightly extended at the time of the measurements. The cricoid cartilage was used as the proximal reference point and the pyloric ring was used as the distal reference point. The white tape was positioned in the prevertebral route, and the blue inelastic polyethylene tape was used for the retrosternal route. The two tapes were carefully aligned at the two references points, and the distances of both routes were measured (Figs 1, 2).
Results
Fig 2. The abdominal incision showing the pylorus (A), the blue inelastic polyethylene tape passed through the retrosternal tunnel (B), and the white tape positioned in the prevertebral route (C).
The median age of all patients was 59.9 years (range, 43 to 79 years). Fifty patients were Chinese men and 10 were women. All patients were diagnosed with esophageal squamous cell carcinoma in the thoracic esophagus. The number of lesions located in the upper, mid, and lower thoracic esophagus were 15, 33, and 12, respectively. All patients received esophagectomy as well as reconstruction using the gastric conduit through AR as planned. The mean distances of AR and PR were 32.7 ⫾ 2.7 cm and 35.5 ⫾ 2.9 cm, respectively. Anterior route is found to be significantly shorter than PR (p ⬍ 0.001). The distances of the two routes are compared in Table 1.
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Table 2. Studies on the Distance of the Anterior and Posterior Routes of Reconstruction Orringer and Sloan [5]
Variable
Ngan and Wong [6]
Coral et al. [7]
Object Number of patients Proximal reference point Distal reference point
cadaver 10 unknown unknown
cadaver
cadaver
20 cricoid cartilage celiac axis
50 cricoid cartilage celiac axis
Result
AR ⬎ PR
AR is 1.9 cm longer than PR
AR is 5.31 cm longer than PR
AR ⫽ anterior route;
Current Study
gastroduodenal artery AR is 2.51 cm longer than PR
Patient in operation 60 cricoid cartilage pyloric ring AR is 2.8 cm shorter than PR
PR ⫽ posterior route.
Comment Esophagectomy followed by reconstruction of the alimentary tract is the mainstay treatment for early stage resectable esophageal cancers. Alimentary tract reconstruction is commonly achieved using a gastric conduit, and can be positioned either through AR or PR [2]. Although various reasons have been cited for selection of the routes, it seems that the choices are influenced more by the preferences and experience of surgeons than by best evidence, as the data available are scarce and controversial. One of the reasons for choosing the posterior route for reconstruction is that it might be shorter, thus associated with reduced tension on the gastric conduit. However, the length of AR and PR has only been measured in limited numbers of cadavers in reported series, and the rationale of the selection of the proximal and distal reference points of measurements was debatable. Understanding the anatomic details with clinical relevance is important for planning treatment strategy for esophageal cancer. In the current study, we compared the lengths of both AR and PR of the gastric conduit using reference points that are more surgically relevant, and discovered that AR is significantly shorter than PR for reconstruction of the alimentary tract after esophagectomy. Specifically, the lengths of AR and PR were 32.7 ⫾ 2.7 cm and 35.5 ⫾ 2.9 cm, respectively (p ⬍ 0.001). The posterior route is preferred by many surgeons because of the perception that it might be associated with fewer complications [2, 3], possibly because of a shorter distance with less anastomotic tension [6, 7]. However, this finding has not been supported by large-scale randomized studies, and a meta-analysis reported by Urschel and colleagues [4] revealed that the choice of reconstruction routes is not significantly associated with the incidences of postoperative morbidities and mortalities. As part of the integrated treatment of esophageal cancer, reconstruction after esophagectomy should be planned with the entire treatment strategy in mind. One of the most important considerations in the management of esophageal cancer, particularly for patients with locally advanced disease, is the utility of neoadjuvant or adjuvant chemotherapy and radiotherapy. Neoadjuvant concurrent chemoradiation has been shown to improve treatment outcome for locally advanced esophageal can-
cer [8, 9]. Despite its efficacy, neoadjuvant or adjuvant chemoradiation is usually associated with substantial side effects and complications. Inflammation and fibrosis of adjacent soft tissues induced by combined chemoradiation will not only complicate surgical maneuvering during esophagectomy but will also adversely affect the postoperative recovery, respiratory capacity, and the functioning of the reconstructed alimentary tract, as well as increasing perioperative morbidity and mortality [10, 11]. In addition, local or regional recurrence is the most common form of treatment failure in patients with locally advanced esophageal cancer after definitive treatment [12]; thus, it is important to consider the possibility that recurrent tumors in the posterior mediastinum may cause obstruction and dysfunction of the gastric conduit when selecting the reconstruction route. With our current finding that AR is significantly shorter than PR, and the prevailing use of trimodality treatment for esophageal cancer in consideration, reconstruction by means of AR after esophagectomy should be considered as the preferable route if there are no other contraindications. The distances of the various routes for alimentary tract reconstruction were addressed previously and most of the studies revealed that the route through the anterior mediastinum is longer than the posterior route. Orringer and Sloan [5] studied 10 cadavers and discovered that the subcutaneous route is 2 to 3 cm longer than the posterior route. They postulated that the length of AR (retrosternal route) would also be longer, as it lies between the lengths of the subcutaneous and the posterior routes. It is important to note that the reference points used for measuring the two routes were not clearly stated in the report. Ngan and Wong [6] measured the distances from the cricoid cartilage to the celiac axis, and reported that AR is 1.9 cm longer than PR after studying 20 cadavers of Asian origin. Similar conclusions were found by Coral and associates [7] using cadavers of African American and Brazilian origins, with the celiac axis and gastroduodenal artery used as the distal reference points. The above-mentioned results seemed to differ substantially from our current findings (Table 2). We contribute these discrepancies to two major reasons. First, although all trials used the cricoid cartilage as the proximal reference point of measurement, the distal reference points used in the previous reports are different from the one we
used. In previously published trials, celiac axis and gastroduodenal artery were used instead. Because the celiac axis is located in the retroperitoneal space, its distance to the cricoid cartilage would be shorter if measured through the posterior mediastinum, as the passage is relatively straight compared with the more tortuous anterior route. However, this direct distance is not clinically relevant when the stomach is used for reconstruction without the Kocher maneuver. Similarly, although the gastroduodenal artery may serve as a fixed reference point to measure the anatomic distance of anterior and posterior mediastinum, it is also not surgically relevant for postesophagectomy reconstruction using the stomach. In the current study, the Kocher maneuver was not performed as we found mobilization of the duodenum was not necessary if the anterior route is used for reconstruction; thus, an unnecessary surgical procedure can be avoided. Therefore, the pyloric ring was chosen as a superior distal reference point because of its clinical relevance. The duodenum is fixed in the retroperitoneal position without performing the Kocher maneuver, and the pyloric ring is essentially fixed in position by the duodenum. Tension to the gastric conduit is present at the pyloric ring distally and the cervical anastomosis proximally. Therefore, the length between the pylorus and the cricoid cartilage is much more representative of the actual distance used for reconstruction. The finding of AR being the shorter route can be
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further explained using our knowledge of gross anatomy. As the pyloric ring is situated more anteriorly in the normal anatomic position (Fig 3), it is clear that using AR (retrosternal route) for transposing the stomach while the duodenum is fixed in position should be more direct and straight. Another possible explanation for the discrepancies between our results and the previous reports may be the different subjects used for measurements. Measurements comparing the two routes were performed only on cadavers in all previous trials, whereas the measurements in our study are performed on patients during esophagectomy before reconstruction. Postmortem changes and procedures for maintaining the cadavers may significantly change the texture of certain human tissues such as the lung. The anatomic structure of a cadaver may only approximate that of a living human body, especially when the magnitude of the differences of the two routes ranges at 2 to 3 cm. Therefore, measurement results obtained during surgery are more accurate as the body and the organs surrounding the reconstruction routes are under normal physiologic conditions. Although we discovered that the anterior route is shorter for postesophagectomy reconstruction using the stomach, whether this route is associated with fewer postoperative complications remains unanswered. Urschel and colleagues [4] reported that no significant differences could be found in the postoperative morbidity and mortality comparing the two procedures in their meta-analysis; however, all studies included in that analysis were completed before the trimodality era, and neoadjuvant treatments were not used for most patients. As neoadjuvant chemoradiation is currently considered part of the standard treatment for locally advanced esophageal cancer, avoiding the tumor bed within the radiotherapy field during reconstruction may be crucial for reducing posttreatment complications of the gastric conduit. However, this probability cannot be sufficiently addressed without a well-designed prospective clinical trial. Esophageal cancer is relatively common in Asia, and most of the cases are treated in tertiary-care hospitals specializing in cancer management. A multicenter randomized clinical trial is currently under development to study the outcome, complications, and quality of life associated with the routes of alimentary tract reconstruction in patients with esophageal carcinoma undergoing trimodality therapy.
References
Fig 3. The pyloric ring is situated more anteriorly in the normal anatomic position.
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9. Tepper J, Krasna M, Niedzwiecki D, et al. Superiority of trimodality therapy to surgery alone in esophageal cancer: results of CALGB 9781. J Clin Oncol 2006;24(Suppl 1):4012 (abstract). 10. Lecleire S, Di Fiore F, Ben-Soussan E, et al. Prior chemoradiotherapy is associated with a higher life-threatening complication rate after palliative insertion of metal stents in patients with oesophageal cancer. Aliment Pharmacol Ther 2006;23:1693–702. 11. Makary MA, Kiernan PD, Sheridan MJ, et al. Multimodality treatment for esophageal cancer. The role of surgery and neoadjuvant therapy. Am Surg 2003;69:693–700. 12. Natsugoe S, Okumura H, Matsumoto M, et al. The role of salvage surgery for recurrence of esophageal squamous cell cancer. Eur J Surg Oncol 2006;32:544 –7.
Requirements for Maintenance of Certification in 2009 Diplomates of the American Board of Thoracic Surgery (ABTS) who plan to participate in the Maintenance of Certification (MOC) process which will begin in 2009 must hold an unrestricted medical license in the locale of their practice and privileges in a hospital accredited by the JCAHO (or other organization recognized by the ABTS). In addition, a valid ABTS certificate is an absolute requirement for entrance into the Maintenance of Certification process. If your certificate has expired, the only pathway for renewal of a certificate is to take and pass the Part I (written) and the Part II (oral) certifying examinations. The names of individuals who have not maintained their certificate will no longer be published in the American Board of Medical Specialties directories. Diplomates’ names will be published upon successful completion of the Maintenance of Certification process. The CME requirements are 30 Category I credits earned during each year prior to application. At least half of these CME hours need to be in the broad area of thoracic surgery. Category II credits are not allowed. Interested individuals should refer to the Booklet of Information for Maintenance of Certification for a complete description of acceptable CME credits. Diplomates in the Maintenance of Certification process will be required to complete all sections of the SESATS
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self-assessment examination. It is not necessary for Diplomates to purchase SESATS individually because it will be sent to them after their application has been approved. Diplomates may apply for Maintenance of Certification in the year their certificate expires, or if they wish to do so, they may apply up to two years before it expires. However, the new certificate will be dated 10 years from the date of expiration of their original certificate or most recent recertification certificate. In other words, going through the Maintenance of Certification process early does not alter the 10-year validation. Diplomates certified prior to 1976 (the year that time-limited certificates were initiated) are also required to participate in MOC if they wish to maintain valid certificates. The deadline for submission of application for the Maintenance of Certification is May 10 of each year. All ABTS diplomates will receive a letter from the Board outlining their individual timeline and MOC requirements. A brochure outlining the rules and requirements for Maintenance of Certification in thoracic surgery is available upon request from the American Board of Thoracic Surgery, 633 North St. Clair St, Suite 2320, Chicago, IL 60611; telephone (312) 202-5900; fax (312) 202-5960; e-mail: [email protected]. This booklet is also published on the website: www.abts.org.
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