Vol. 218, No. 5, May 2014
cystic duct when the tie used to secure the catheter does not properly occlude the duct around the cholangiogram catheter. In these cases, the injected bile duct air will preferentially leak at the cholangiogram catheter insertion site, preventing detection of open bile ducts along the parenchymal transection surface. In addition, with our technique, the insufflation pressure on the common duct is monitored throughout the performance of the test with palpation of the distension within the bile duct with the left hand, and the amount of pressure is effectively gauged based on the pneumatic recoil of the plunger of the syringe in the right hand (see Figure 2A in the article). For this reason, we would disagree with the use of a tourniquet to occlude the common bile duct. The ability to bimanually measure and control the pressure applied to the bile duct system as the test is being performed is an important component in the safe and effective application of the ALT. In our experience, the technical success rate for the transcystic approach is >90%, and the technique eliminates any risk of leak and/or stricture that can result from direct puncture, tourniquet, and suture repair of the common bile duct. Second, Dr Kayaalp argues that the direct puncture technique can eliminate the need for ultrasound guidance. Perhaps Dr Kayaalp did not appreciate that confirmation of retrograde air flow in the bile duct is the secondary purpose of the ultrasound maneuver. The primary purpose of part one of the ALT is to confirm bile duct patency. Unlike the Figure submitted by Dr Kayaalp describing a bile leak test after limited partial right hepatectomy, we are using the ALT after hemi- or extended hepatectomy where tumor locations and earlier portal vein embolization frequently mandate a close division of main left or right bile ducts at the biliary bifurcation. Using the direct puncture technique, water, and no ultrasound evaluation, there would be no means to use this method to confirm patency of the biliary confluence after such operations. A negative water leak test using Dr Kayaalp’s technique could be due to occlusion of the bile duct confluence or an anatomical variant, such as a very low cystic to common duct confluence yielding a false-negative result, under-recognition of a potentially catastrophic complication, and/or invalidation of the second step of the ALT. We, therefore, believe there is significant value to the use of air injection under ultrasound guidance to begin the test. In summary, the ALT is associated with a high technical success rate, safe monitoring of intrabiliary pressure, and complete interrogation of the bile duct system with the combined 2 steps designed to evaluate both the patency of the bile duct system and the integrity of peritransectional bile duct closure.
Letters
1079
REFERENCE 1. Zimmitti G, Vauthey JN, Shindoh J, et al. Systematic use of an intraoperative air leak test at the time of major liver resection reduces the rate of postoperative biliary complications. J Am Coll Surg 2013;217:1028e1037.
Disclosure Information: Nothing to disclose.
Optimizing Prosthetic Technique for Ventral Hernia Repair Tetsuji Fujita, Tokyo, Japan
MD
I enjoyed the article1 from the University of Texas MD Anderson Cancer Center, in which bridged mesh repair (hazard ratio ¼ 7.27; 95% CI, 3.3815.65) and fascial defect width >15 cm (hazard ratio ¼ 2.46; 95% CI, 1.105.46) predicted the failure of ventral hernia repair during a mean follow-up period of 31 months. Dr Booth and colleagues1 stated that bridged repair and defect width are independently associated with hernia recurrence in a multiple logistic regression model, perhaps meaning that bridged repair is more responsible for recurrence than defect width, given a greater hazard ratio and higher lower limit of 95% CI of bridged repair than of defect width. This statement might mislead the readers to the assumption that the majority of recurrences are attributable to inappropriate surgical procedures that are independent of patient-related risk factors for recurrence, such as previous repairs and obesity. Multiple logistic regression analysis is performed to construct a best-fit statistical model for predicting primary outcomes. The algorithms for covariate selection are forward or backward stepwise regression analysis, which is repeated until no additional model changes occur during one complete cycle. If an explanatory variable and another explanatory variable are highly correlated, their effects on the primary outcomes might be overestimated or underestimated.2,3 When looking at the data presented in Table 1 of the article,1 patients who received bridged repair had significantly wider fascial defect than those who received mesh-reinforced primary fascial coaptation, suggesting a correlation between bridged repair and defect width. Also, in a previous study that compared primary fascial reapproximation and bridged repair, the relationship between requirements for a bridged repair and larger defects was inferred.4 Therefore, constructing multilevel regression models excluding either bridged repair or defect size from explanatory variables would be feasible to estimate the independent effect of bridged repair or defect width on hernia recurrence. Dr Booth and colleagues1
1080
Letters
consider nonrandomization of patients a limitation of their study. If the objective of a retrospective study is to answer the same question as a randomized controlled trial, propensity score-matched analysis, which can estimate treatment effects on the population, appears to be more feasible than conventional multivariate regression analysis.5 In the study by Dr Booth and colleagues,1 overall recurrence rate was 13.5% (30 of 222), which is higher than 5% at a mean follow-up duration of 70 months after the Rives-Stoppa retrorecutus inlay repair for clean abdominal wound defects in 254 patients.6 Of course, it might be meaningless to compare recurrence rates among cohorts with different prevalence of established risk factors for hernia recurrence. Dr Booth and colleagues1 mention that they generally use synthetic mesh for clean cases in which mesh is not required to be placed against the bowel, and all patients included in the study underwent preperitoneal or peritoneal mesh repair. As shown in the Tables of the article,1 about 96% of meshes used for reconstruction were bioprosthetic (ie, human, bovine, or porcine acellular dermal matrix), and 44% of the wounds were contaminated at the time of operation. These findings suggest that, in the majority of patients who underwent a bridged repair, acellular dermal matrix graft was placed as a replacement of abdominal fascia because of a large and/or potentially contaminated fascial defect. Bridged repairs with human acellular dermal matrix have been reported to be expensive and associated with a high recurrence rate up to 80%.7,8 In the early experience of human acellular dermis for ventral hernia repair, the limitation of single-layer repairs was known if native fascia was scarce or if primary closure was under undue tension.9 In such cases, the multilayer repair using bioprosthetic meshes would reduce recurrence rates.9 For example, a second layer of bioprosthetic sheets is attached to the rectus or external oblique fascia over the first layer under the same tension as the first layer. However, extended necrosis of superficial and deep abdominal muscles and their fascias due to wound sepsis precludes multilayer repairs with bioprosthetic sheets. In contaminated abdominal wall defects, use of nonabsorbable prosthetic meshes, such as polytetrafluoroethylene and polypropylene, is contraindicated because of high risk for infection and bowel erosion. Although absorbable prosthetic meshes, including polyglycolic acid and polyglactin, are less likely to promote infection and erosion,10 the tensile strength of absorbable meshes is inferior to that of nonabsorbable meshes,11 and the strength decreases with absorption of meshes. In such difficult conditions with wound contamination and absence of native fascia enough to perform a mesh-reinforced primary fascial coaptation
J Am Coll Surg
despite component separation, suturing multiple sheets of acellular dermal matrix to the native fascial edge circumferentially12 might be the obligatory method to achieve a tension-free repair with minimal risk of postoperative wound infection. The Rives-Stoppa repair and modified procedures with synthetic meshes appear to be associated with the lowest risk of recurrence, 5% for complex incisional hernia, when the abdominal wall is not contaminated and retrorecutus space can be entirely dissected. As for techniques for the Rives-Stoppa repair, Stoppa advised that all attempts should be made to bury the polyester mesh beneath a reconstructed parietal layer, even if that means making incisions in the anterior lamina of the rectus sheath.13 Closing midline fascia over the mesh is likely protective against recurrences at the caudal and cranial edges of the repair.14 In some cases, primary closure of the anterior fascia is difficult to perform because of lack of native anterior fascia and/ or excessive tension, in which sandwich repair using a second nonabsorbable mesh might decrease the recurrence.15 Sandwich repairs did not increase wound complications such as seroma and mesh infections, and decreased hernia recurrence.16 Alternatively, securing the fascial margins to the mesh surface as medially as possible was associated with an acceptable recurrence rate of 5.5% in morbidly obese patients.17 In this series, 4 of 5 recurrences occurred at the superior pole of the repair. In another series of 32 patients who underwent the modified Rives-Stoppa repair with or without closure of the midline fascia for multiply recurrent incisional hernias, only one recurrence was observed during a mean follow-up of 28.1 months.18 This recurrence was due to mesh infection. After reviewing a total number of 8,822 patients who underwent mesh repair for ventral hernia and a total of 437 recurrences, Awad and colleagues19 proposed a classification of mechanisms of recurrences. The mechanisms are divided into patient factors and technical factors. Patient factors consist of increased intra-abdominal pressure and diminished tissue integrity. Among technical factors, the leading cause of recurrence was mesh infection (32%), followed by lateral detachment of the mesh (23%) and inadequate mesh fixation (21%). Taken together, for clean but large abdominal wall defects, the Rives-Stoppa repair with sufficient overlap of synthetic meshes with the lateral edges of native fascia seems to be most protective against hernia recurrence. If primary fascial reapproximation is not feasible, despite component separation, sandwich repair would be recommended. Multilayer repairs with biologic meshes would be feasible for contaminated large fascial defects. Because preoperative CT could predict abdominal closure after component separation,20 surgeons are encouraged to prepare for optimal prosthetic techniques for ventral hernia repair.
Vol. 218, No. 5, May 2014
REFERENCES 1. Booth JH, Garvey PB, Baumann DP, et al. Primary fascial closure with mesh reinforcement is superior to bridged mesh repair for abdominal wall reconstruction. J Am Coll Surg 2013;217:999e1009. 2. Tripepi G, Jager KJ, Stel VS, et al. How to deal with continuous and dichotomic outcomes in epidemiological research: linear and logistic regression analyses. Nephron Clin Pract 2011;118:c399ec406. 3. Greenland S. Modeling and variable selection in epidemiologic analysis. Am J Public Health 1989;79:340e349. 4. Candage R, Jones K, Luchette FA, et al. Use of human acellular dermal matrix for hernia repair: friend or foe? Surgery 2008;144:703e711. 5. Austin PC. An introduction to propensity score methods for reducing the effects of confounding in observational studies. Multivariate Behav Res 2011;46:399e424. 6. Iqbal CW, Pham TH, Joseph A, et al. Long-term outcomes of 254 complex incisional hernia repairs using the modified Rives-Stoppa technique. World J Surg 2007;31: 2398e2404. 7. Jin J, Rosen MJ, Blatnik J, et al. Use of acellular dermal matrix for complicated ventral hernia repair: does technique affect outcomes? J Am Coll Surg 2007;205:654e660. 8. Blatnik J, Jin J, Rosen M. Abdominal hernia repair with bridging acellular dermal matrixdan expensive hernia sac. Am J Surg 2008;196:47e50. 9. Buinewicz B, Rosen B. Acellular cadaveric dermis (AlloDerm): a new alternative for abdominal hernia repair. Ann Plast Surg 2004;52:188e194. 10. Dayton MT, Buchele BA, Shirazi SS, Hunt LB. Use of an absorbable mesh to repair contaminated abdominal-wall defects. Arch Surg 1986;121:954e960. 11. Tyrell J, Silberman H, Chadrasoma P, et al. Absorbable versus permanent mesh in abdominal operations. Surgery 1989;168: 227e232. 12. Hirsch EF. Repair of an abdominal wall defect after a salvage laparotomy for sepsis. J Am Coll Surg 2004;198:324e328. 13. Stoppa RE. The treatment of complicated groin and incisional hernias. World J Surg 1989;13:545e554. 14. Gleysteen JJ. Mesh-reinforced ventral hernia repair. Arch Surg 2009;144:740e745. 15. Schmidbauer S, Ladurner R, Hallfeldt KK, Mussack T. Heavyweight versus low-weight polypropylene meshes for open sublay mesh repair of incisional hernia. Eur J Med Res 2005;10: 247e253. 16. Satterwhite TS, Miri S, Chung C, et al. Outcomes of complex abdominal herniorrhaphy: experiences with 106 cases. Ann Plast Surg 2012;59:382e388. 17. Moore M, Bax T, MacFarlane M, McNevin MS. Outcomes of the fascial component separation technique with synthetic mesh reinforcement for repair of complex ventral incisional hernias in the morbidly obese. Am J Surg 2008;195: 575e579. 18. Novitsky YW, Porter JR, Rucho ZC, et al. Open preperitoneal retrofascial mesh repair for multiply recurrent ventral incisional hernias. J Am Coll Surg 2006;203: 283e289. 19. Awad ZT, Puri V, LeBlanc K, et al. Mechanisms of ventral hernia recurrence after mesh repair and a new proposed classification. J Am Coll Surg 2005;201:132e140.
Letters
1081
20. Franklin BR, Patel KM, Nahabedian MY, et al. Predicting abdominal closure after component separation for complex ventral hernias: maximizing the use of preoperative computed tomography. Ann Plast Surg 2013;71:261e265.
Disclosure Information: Nothing to disclose.
Reply Patrick B Garvey, MD, FACS, Justin H Booth, MD, Donald P Baumann, MD, FACS, Jesse C Selber, MD, MPH, FACS, Alexander T Nguyen, MD, Mark W Clemens, MD, Jun Liu, MD, PhD, Charles E Butler, MD, FACS Houston, TX One of the interesting aspects of abdominal wall reconstruction is that, as in many other surgical specialties, there is a wide variety of divergent opinions about surgical decision making. Unfortunately, credible, evidence-based data are often insufficient to support or refute many of the widespread and often anecdotal opinions held by surgeons. Perhaps one of the reasons for this is that there is considerable heterogeneity among patients who undergo abdominal wall reconstruction. The cause of these defects, the chronicity of patient comorbidities, and the specific characteristics of the abdominal wall defect vary considerably among patients who require complex abdominal wall reconstruction. Although opinions and historical practice patterns are important, credible, evidence-based, patientspecific data are critical to defining best practices in this field. The author of the letter to the editor suggests that our peer-reviewed publication might “mislead the readers” into assuming that hernia recurrence is attributable to “inappropriate” surgical procedures. In particular, the author of the letter to the editor proposes that it is simply the defect size, rather than the use of a bridged vs reinforced repair, that is associated with hernia recurrence. We believe that the best way to advance the state of the art in our profession is through evidence-based research and the process of peer-reviewed scientific publication. We developed a well-powered study with carefully designed methodology, including multiple regression analysis. Certainly, any study has flaws, which we acknowledged in our article. Selection bias is a common issue for any nonrandomized study. The author of the letter to the editor proposes that the use of propensity score-matched analysis would have minimized selection bias in our study. However, this design is typically limited to studies with very large sample sizes because matching reduces the sample size greatly. For this
cystic duct when the tie used to secure the catheter does not properly occlude the duct around the cholangiogram catheter. In these cases, the injected bile duct air will preferentially leak at the cholangiogram catheter insertion site, preventing detection of open bile ducts along the parenchymal transection surface. In addition, with our technique, the insufflation pressure on the common duct is monitored throughout the performance of the test with palpation of the distension within the bile duct with the left hand, and the amount of pressure is effectively gauged based on the pneumatic recoil of the plunger of the syringe in the right hand (see Figure 2A in the article). For this reason, we would disagree with the use of a tourniquet to occlude the common bile duct. The ability to bimanually measure and control the pressure applied to the bile duct system as the test is being performed is an important component in the safe and effective application of the ALT. In our experience, the technical success rate for the transcystic approach is >90%, and the technique eliminates any risk of leak and/or stricture that can result from direct puncture, tourniquet, and suture repair of the common bile duct. Second, Dr Kayaalp argues that the direct puncture technique can eliminate the need for ultrasound guidance. Perhaps Dr Kayaalp did not appreciate that confirmation of retrograde air flow in the bile duct is the secondary purpose of the ultrasound maneuver. The primary purpose of part one of the ALT is to confirm bile duct patency. Unlike the Figure submitted by Dr Kayaalp describing a bile leak test after limited partial right hepatectomy, we are using the ALT after hemi- or extended hepatectomy where tumor locations and earlier portal vein embolization frequently mandate a close division of main left or right bile ducts at the biliary bifurcation. Using the direct puncture technique, water, and no ultrasound evaluation, there would be no means to use this method to confirm patency of the biliary confluence after such operations. A negative water leak test using Dr Kayaalp’s technique could be due to occlusion of the bile duct confluence or an anatomical variant, such as a very low cystic to common duct confluence yielding a false-negative result, under-recognition of a potentially catastrophic complication, and/or invalidation of the second step of the ALT. We, therefore, believe there is significant value to the use of air injection under ultrasound guidance to begin the test. In summary, the ALT is associated with a high technical success rate, safe monitoring of intrabiliary pressure, and complete interrogation of the bile duct system with the combined 2 steps designed to evaluate both the patency of the bile duct system and the integrity of peritransectional bile duct closure.
Letters
1079
REFERENCE 1. Zimmitti G, Vauthey JN, Shindoh J, et al. Systematic use of an intraoperative air leak test at the time of major liver resection reduces the rate of postoperative biliary complications. J Am Coll Surg 2013;217:1028e1037.
Disclosure Information: Nothing to disclose.
Optimizing Prosthetic Technique for Ventral Hernia Repair Tetsuji Fujita, Tokyo, Japan
MD
I enjoyed the article1 from the University of Texas MD Anderson Cancer Center, in which bridged mesh repair (hazard ratio ¼ 7.27; 95% CI, 3.3815.65) and fascial defect width >15 cm (hazard ratio ¼ 2.46; 95% CI, 1.105.46) predicted the failure of ventral hernia repair during a mean follow-up period of 31 months. Dr Booth and colleagues1 stated that bridged repair and defect width are independently associated with hernia recurrence in a multiple logistic regression model, perhaps meaning that bridged repair is more responsible for recurrence than defect width, given a greater hazard ratio and higher lower limit of 95% CI of bridged repair than of defect width. This statement might mislead the readers to the assumption that the majority of recurrences are attributable to inappropriate surgical procedures that are independent of patient-related risk factors for recurrence, such as previous repairs and obesity. Multiple logistic regression analysis is performed to construct a best-fit statistical model for predicting primary outcomes. The algorithms for covariate selection are forward or backward stepwise regression analysis, which is repeated until no additional model changes occur during one complete cycle. If an explanatory variable and another explanatory variable are highly correlated, their effects on the primary outcomes might be overestimated or underestimated.2,3 When looking at the data presented in Table 1 of the article,1 patients who received bridged repair had significantly wider fascial defect than those who received mesh-reinforced primary fascial coaptation, suggesting a correlation between bridged repair and defect width. Also, in a previous study that compared primary fascial reapproximation and bridged repair, the relationship between requirements for a bridged repair and larger defects was inferred.4 Therefore, constructing multilevel regression models excluding either bridged repair or defect size from explanatory variables would be feasible to estimate the independent effect of bridged repair or defect width on hernia recurrence. Dr Booth and colleagues1
1080
Letters
consider nonrandomization of patients a limitation of their study. If the objective of a retrospective study is to answer the same question as a randomized controlled trial, propensity score-matched analysis, which can estimate treatment effects on the population, appears to be more feasible than conventional multivariate regression analysis.5 In the study by Dr Booth and colleagues,1 overall recurrence rate was 13.5% (30 of 222), which is higher than 5% at a mean follow-up duration of 70 months after the Rives-Stoppa retrorecutus inlay repair for clean abdominal wound defects in 254 patients.6 Of course, it might be meaningless to compare recurrence rates among cohorts with different prevalence of established risk factors for hernia recurrence. Dr Booth and colleagues1 mention that they generally use synthetic mesh for clean cases in which mesh is not required to be placed against the bowel, and all patients included in the study underwent preperitoneal or peritoneal mesh repair. As shown in the Tables of the article,1 about 96% of meshes used for reconstruction were bioprosthetic (ie, human, bovine, or porcine acellular dermal matrix), and 44% of the wounds were contaminated at the time of operation. These findings suggest that, in the majority of patients who underwent a bridged repair, acellular dermal matrix graft was placed as a replacement of abdominal fascia because of a large and/or potentially contaminated fascial defect. Bridged repairs with human acellular dermal matrix have been reported to be expensive and associated with a high recurrence rate up to 80%.7,8 In the early experience of human acellular dermis for ventral hernia repair, the limitation of single-layer repairs was known if native fascia was scarce or if primary closure was under undue tension.9 In such cases, the multilayer repair using bioprosthetic meshes would reduce recurrence rates.9 For example, a second layer of bioprosthetic sheets is attached to the rectus or external oblique fascia over the first layer under the same tension as the first layer. However, extended necrosis of superficial and deep abdominal muscles and their fascias due to wound sepsis precludes multilayer repairs with bioprosthetic sheets. In contaminated abdominal wall defects, use of nonabsorbable prosthetic meshes, such as polytetrafluoroethylene and polypropylene, is contraindicated because of high risk for infection and bowel erosion. Although absorbable prosthetic meshes, including polyglycolic acid and polyglactin, are less likely to promote infection and erosion,10 the tensile strength of absorbable meshes is inferior to that of nonabsorbable meshes,11 and the strength decreases with absorption of meshes. In such difficult conditions with wound contamination and absence of native fascia enough to perform a mesh-reinforced primary fascial coaptation
J Am Coll Surg
despite component separation, suturing multiple sheets of acellular dermal matrix to the native fascial edge circumferentially12 might be the obligatory method to achieve a tension-free repair with minimal risk of postoperative wound infection. The Rives-Stoppa repair and modified procedures with synthetic meshes appear to be associated with the lowest risk of recurrence, 5% for complex incisional hernia, when the abdominal wall is not contaminated and retrorecutus space can be entirely dissected. As for techniques for the Rives-Stoppa repair, Stoppa advised that all attempts should be made to bury the polyester mesh beneath a reconstructed parietal layer, even if that means making incisions in the anterior lamina of the rectus sheath.13 Closing midline fascia over the mesh is likely protective against recurrences at the caudal and cranial edges of the repair.14 In some cases, primary closure of the anterior fascia is difficult to perform because of lack of native anterior fascia and/ or excessive tension, in which sandwich repair using a second nonabsorbable mesh might decrease the recurrence.15 Sandwich repairs did not increase wound complications such as seroma and mesh infections, and decreased hernia recurrence.16 Alternatively, securing the fascial margins to the mesh surface as medially as possible was associated with an acceptable recurrence rate of 5.5% in morbidly obese patients.17 In this series, 4 of 5 recurrences occurred at the superior pole of the repair. In another series of 32 patients who underwent the modified Rives-Stoppa repair with or without closure of the midline fascia for multiply recurrent incisional hernias, only one recurrence was observed during a mean follow-up of 28.1 months.18 This recurrence was due to mesh infection. After reviewing a total number of 8,822 patients who underwent mesh repair for ventral hernia and a total of 437 recurrences, Awad and colleagues19 proposed a classification of mechanisms of recurrences. The mechanisms are divided into patient factors and technical factors. Patient factors consist of increased intra-abdominal pressure and diminished tissue integrity. Among technical factors, the leading cause of recurrence was mesh infection (32%), followed by lateral detachment of the mesh (23%) and inadequate mesh fixation (21%). Taken together, for clean but large abdominal wall defects, the Rives-Stoppa repair with sufficient overlap of synthetic meshes with the lateral edges of native fascia seems to be most protective against hernia recurrence. If primary fascial reapproximation is not feasible, despite component separation, sandwich repair would be recommended. Multilayer repairs with biologic meshes would be feasible for contaminated large fascial defects. Because preoperative CT could predict abdominal closure after component separation,20 surgeons are encouraged to prepare for optimal prosthetic techniques for ventral hernia repair.
Vol. 218, No. 5, May 2014
REFERENCES 1. Booth JH, Garvey PB, Baumann DP, et al. Primary fascial closure with mesh reinforcement is superior to bridged mesh repair for abdominal wall reconstruction. J Am Coll Surg 2013;217:999e1009. 2. Tripepi G, Jager KJ, Stel VS, et al. How to deal with continuous and dichotomic outcomes in epidemiological research: linear and logistic regression analyses. Nephron Clin Pract 2011;118:c399ec406. 3. Greenland S. Modeling and variable selection in epidemiologic analysis. Am J Public Health 1989;79:340e349. 4. Candage R, Jones K, Luchette FA, et al. Use of human acellular dermal matrix for hernia repair: friend or foe? Surgery 2008;144:703e711. 5. Austin PC. An introduction to propensity score methods for reducing the effects of confounding in observational studies. Multivariate Behav Res 2011;46:399e424. 6. Iqbal CW, Pham TH, Joseph A, et al. Long-term outcomes of 254 complex incisional hernia repairs using the modified Rives-Stoppa technique. World J Surg 2007;31: 2398e2404. 7. Jin J, Rosen MJ, Blatnik J, et al. Use of acellular dermal matrix for complicated ventral hernia repair: does technique affect outcomes? J Am Coll Surg 2007;205:654e660. 8. Blatnik J, Jin J, Rosen M. Abdominal hernia repair with bridging acellular dermal matrixdan expensive hernia sac. Am J Surg 2008;196:47e50. 9. Buinewicz B, Rosen B. Acellular cadaveric dermis (AlloDerm): a new alternative for abdominal hernia repair. Ann Plast Surg 2004;52:188e194. 10. Dayton MT, Buchele BA, Shirazi SS, Hunt LB. Use of an absorbable mesh to repair contaminated abdominal-wall defects. Arch Surg 1986;121:954e960. 11. Tyrell J, Silberman H, Chadrasoma P, et al. Absorbable versus permanent mesh in abdominal operations. Surgery 1989;168: 227e232. 12. Hirsch EF. Repair of an abdominal wall defect after a salvage laparotomy for sepsis. J Am Coll Surg 2004;198:324e328. 13. Stoppa RE. The treatment of complicated groin and incisional hernias. World J Surg 1989;13:545e554. 14. Gleysteen JJ. Mesh-reinforced ventral hernia repair. Arch Surg 2009;144:740e745. 15. Schmidbauer S, Ladurner R, Hallfeldt KK, Mussack T. Heavyweight versus low-weight polypropylene meshes for open sublay mesh repair of incisional hernia. Eur J Med Res 2005;10: 247e253. 16. Satterwhite TS, Miri S, Chung C, et al. Outcomes of complex abdominal herniorrhaphy: experiences with 106 cases. Ann Plast Surg 2012;59:382e388. 17. Moore M, Bax T, MacFarlane M, McNevin MS. Outcomes of the fascial component separation technique with synthetic mesh reinforcement for repair of complex ventral incisional hernias in the morbidly obese. Am J Surg 2008;195: 575e579. 18. Novitsky YW, Porter JR, Rucho ZC, et al. Open preperitoneal retrofascial mesh repair for multiply recurrent ventral incisional hernias. J Am Coll Surg 2006;203: 283e289. 19. Awad ZT, Puri V, LeBlanc K, et al. Mechanisms of ventral hernia recurrence after mesh repair and a new proposed classification. J Am Coll Surg 2005;201:132e140.
Letters
1081
20. Franklin BR, Patel KM, Nahabedian MY, et al. Predicting abdominal closure after component separation for complex ventral hernias: maximizing the use of preoperative computed tomography. Ann Plast Surg 2013;71:261e265.
Disclosure Information: Nothing to disclose.
Reply Patrick B Garvey, MD, FACS, Justin H Booth, MD, Donald P Baumann, MD, FACS, Jesse C Selber, MD, MPH, FACS, Alexander T Nguyen, MD, Mark W Clemens, MD, Jun Liu, MD, PhD, Charles E Butler, MD, FACS Houston, TX One of the interesting aspects of abdominal wall reconstruction is that, as in many other surgical specialties, there is a wide variety of divergent opinions about surgical decision making. Unfortunately, credible, evidence-based data are often insufficient to support or refute many of the widespread and often anecdotal opinions held by surgeons. Perhaps one of the reasons for this is that there is considerable heterogeneity among patients who undergo abdominal wall reconstruction. The cause of these defects, the chronicity of patient comorbidities, and the specific characteristics of the abdominal wall defect vary considerably among patients who require complex abdominal wall reconstruction. Although opinions and historical practice patterns are important, credible, evidence-based, patientspecific data are critical to defining best practices in this field. The author of the letter to the editor suggests that our peer-reviewed publication might “mislead the readers” into assuming that hernia recurrence is attributable to “inappropriate” surgical procedures. In particular, the author of the letter to the editor proposes that it is simply the defect size, rather than the use of a bridged vs reinforced repair, that is associated with hernia recurrence. We believe that the best way to advance the state of the art in our profession is through evidence-based research and the process of peer-reviewed scientific publication. We developed a well-powered study with carefully designed methodology, including multiple regression analysis. Certainly, any study has flaws, which we acknowledged in our article. Selection bias is a common issue for any nonrandomized study. The author of the letter to the editor proposes that the use of propensity score-matched analysis would have minimized selection bias in our study. However, this design is typically limited to studies with very large sample sizes because matching reduces the sample size greatly. For this
