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Abdominal strength after breast reconstruction using a free abdominal flap
Journal of Plastic, Reconstructive & Aesthetic Surgery (2007) 60, 519e523
Abdominal strength after breast reconstruction using a free abdominal flap* Christian T. Bonde a,*, Hans Lund b, Marie Fridberg a, Bente Danneskiold-Samsoe b, Jens J. Elberg a a
Department of Plastic Surgery and Burns Unit, Center of Head and Orthopedics, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark b Parker Institute, Frederiksberg Hospital, DK-2000 Frederiksberg, Denmark Received 29 May 2006; accepted 22 July 2006
KEYWORDS Breast reconstruction; Abdominal strength; DIEP; TRAM; Isokinetic dynamometer
Summary Background: Today, breast reconstruction with autologous tissue is most commonly done either as a free muscle sparring TRAM flap or as a DIEP flap. Studies of donor site morbidity have shown an advantage in using the DIEP flap. However, this procedure might also be associated with an increased risk of flow related complications and it is also thought to be more demanding and time consuming. A few studies have evaluated the abdominal wall strength after dissection of a TRAM flap or a DIEP flap. However, these studies do not distinguish between the various types of free TRAM flaps and they also compare TRAM procedures preformed in an early period to DIEP procedures done in a later period. Methods: We used an isokinetic dynamometer to measure concentric, eccentric and isometric abdominal muscle strength in 32 patients who had had a unilateral breast reconstruction with a free MS-2 (15) or a DIEP (17) flap in the year 2003. Results: No significant reduction in muscle strength was observed for concentric or isometric muscle strength. However, significant lower eccentric muscle strength was found in the TRAM compared to the DIEP group (p Z 0.05). There was no significant difference in abdominal strength between the two flap groups at low to moderate work intensity (isometric/concentric). At the greatest work intensity (eccentric muscle strength) the patients reconstructed with a DIEP flap had a clinical small, but significant advantage over the patients reconstructed with a MS-2 TRAM flap. ª 2006 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
* Presented at the 2006 Annual Scientific meeting of the American Society for Reconstructive Microsurgery, Loews Ventana Canyon Resort, Tucson, AZ, USA. January 14e17, 2006. * Corresponding author. Tel.: þ45 35458963, þ45 32542333 (private); fax: þ45 35452667. E-mail address: [email protected] (C.T. Bonde).
1748-6815/$ - see front matter ª 2006 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2006.07.003
520 The transverse rectus abdominis musculocutaneous (TRAM) flap was, for many years, the standard in autologous tissue breast reconstruction.1,2 However, harvesting the TRAM flap leads to weakening of the abdominal wall.3 This weakening can be reduced by using a muscle-sparing TRAM flap in which only a small medial part of the muscle is included in the flap.4 The muscle-sparing (MS) techniques have been classified and include the MS-0, MS-1, and MS-2 free TRAM flaps.5,6 The MS-2 free TRAM flap used in this study, where both the medial and the lateral are preserved, causes the least amount of damage to the abdominal integrity and is most similar to the deep inferior epigastric perforator flap (DIEP) (MS-3). During the last decade, the DIEP flap7e9 has been found to be a superior reconstructive option because of minimal donor site morbidity.8,10 The DIEP flap preserves the anterior rectus sheath and the integrity of the abdominis muscle and reduces the incidence of abdominal weakness, bulge and hernia. However, the DIEP procedure might also be associated with an increased risk of flow related complications such as venous congestion and fat necrosis.11 The DIEP flap procedure is also thought to be more technically demanding and the DIEP flap procedure takes longer time to perform due to the dissection of the perforators through the muscle. A few studies have evaluated the abdominal wall strength after dissection of a TRAM flap or a DIEP flap. However, these studies do not distinguish between the various types of free TRAM flaps and they also compare TRAM procedures preformed in an early period to DIEP procedures done in a later period. Not surprisingly, decreased abdominal wall strength has been found in the TRAM groups. Blondeel et al.10 used isokinetic dynamometry to examine the difference in abdominal strength after breast reconstruction using free, full muscle TRAM flaps and DIEP flaps. He found that the full muscle TRAM flap group had a significant reduction in the strength to flex and rotate the upper trunk compared to the DIEP flap group. Using isokinetic dynamometry, Futter found a significant difference in flexion strength during eccentric and isometric contraction between the DIEP flap group and the free MS-2 TRAM flap group.12 However, patients included were operated over a period of 5 years with an average time since reconstruction of 41 months for the TRAM group and 19 months for the DIEP group. In a recent study comparing reconstructions performed with a MS-2 free TRAM flap or a DIEP flap, Nahabedian found no significant difference in the ability of to perform sit-ups.13 However, patients included were operated over a period of 5 years with an average time since reconstruction of 41 months for the TRAM group and 19 months for the DIEP group. No study, using isokinetic dynamometry has examined patients operated in the same period of time and with the same follow-up period.
C.T. Bonde et al. Table 1 Mean (standard deviation, SD) age, weight, height, follow-up time, operating time and mean length of hospital
Age (years) Weight (kg) Height (cm) Follow-up time (months) Operating time (min) Length of hospital stay (days)
DIEP flaps (n Z 17)
MS-2 TRAM flaps (n Z 15)
54 70.8 166.6 24 351 7.4
53 73.3 167.1 24 344 7.5
(6.5) (11.1) (7.6) (3.1) (62.3) (1.0)
(8.9) (8.4) (7.3) (3.5) (80.5) (1.5)
15 patients had a breast reconstruction using a free MS-2 TRAM flap and 17 patients had a breast reconstruction using a free DIEP flap. The median age, follow-up time, operating time and median length of hospital stay were comparable in both groups (Table 1). All procedures were performed by the same microsurgical team consisting of three senior consultants and two microsurgical trainees. A DIEP flap reconstruction is performed if possible, but, due to being a training department, we chose to convert the procedure to a MS-2 if more than two perforators are required for the DIEP flap based on intra-operative clinical evaluation of flap perfusion. The sheath of the rectus muscle is sutured using polypropylene 2/0 (Prolene) and no mesh is used.
Abdominal muscle strength measurements To define the patient’s maximal muscle strength we used an isokinetic dynamometer (Biodex System 3, PRO, Biodex Medical System, NY, USA) (Fig. 1). The dynamometer is made from a motor that moves a test arm with a constant speed throughout the whole range of motion (ROM) and which registers the entire torque influencing the test arm. A computer is connected to the system. It collects torque, velocity and the ROM angle and thus indirectly registers the dynamic muscle power. The dynamometer is warmed up and calibrated on a daily basis before measuring.
Materials and methods Patient material All patients who had had a unilateral breast reconstruction with a free MS-2 or a DIEP flap in the year 2003 (n Z 43) were included. Thirty-two agrees to participate. Of these,
Figure 1 Abdominal muscle strength testing in the isokinetic dynamometer.
Abdominal strength after breast reconstruction Table 2
521
Types of muscle contraction
Effect
Used in
Isometric
Concentric
Eccentric
Generates tension, no movement
Contraction, muscle shortening
Muscle lengthens under tension
Trunk stability
Trunk flexion
Trunk flexion
Standing position
Trunk flexion, curl ups
Lifting, vacuum cleaning
Abdominal muscle strength was measured as concentric, eccentric and isometric muscle strength, in the mentioned order. Concentric activity of a muscle occurs when the muscle is contracting whilst simultaneously shortening. An example could be trunk flexion during curl ups. With eccentric muscle activity, the muscle lengthens in a controlled manner whilst simultaneously maintaining tension. This is the most demanding contraction type, used for example during vacuum cleaning and lifting. During an isometric muscle contraction, tension is generated within the muscle but no movement occurs. This is used in stabilizing the trunk, for example when in a standing position (Table 2). The standard test consists of three repetitions at 30 s1 for both concentric and eccentric and five repetitions for isometric muscle strength. The isometric test was performed at 105 flexion of the hip (position of mechanical advantage for rectus abdominis). All tests were performed in a sitting position. A trial run of three sub-maximal muscle contractions was given initially as a warm-up and to familiarize the patient with the dynamometer. Throughout each test, a maximal effort was strongly encouraged in a standardized manner (Fig. 1), and a 30-s rest was allowed between each test. If the coefficient of variance (CV%) between the three (concentric and eccentric) or five (isometric) tests were higher than 10%, the measurement was repeated. If the CV% still was above 10% the session with the lowest CV% was chosen. The best of three repetitions was chosen as maximal concentric or eccentric muscle strength (peak torque), and the best of five for isometric (peak torque).
Statistical analysis Muscle strength data were analysed both as peak torque and peak torque adjusted for body weight. A Student’s t-test was applied with 2a < 0.05 as level of significance.
Results The results from the measurements of the abdominal strength are presented in Table 3. No significant reduction in muscle strength was observed for concentric or isometric muscle strength, neither uncorrected nor corrected for body weight. However, a significant lower eccentric muscle strength was found in the TRAM group (n Z 15) compared to the DIEP group (n Z 17) (123.8 Nm vs. 135.4 Nm, p Z 0.05), but only after correction for body weight. A 95% confidence interval on the difference ranged from 23.2 Nm to 0.007 Nm.
Discussion The advantage of using DIEP flaps instead of TRAM flaps for breast reconstruction has been debated for years. Most of the research done on the abdominal wall strength has been qualitative with few objective measurements. Older studies, focusing on the differences between pedicled and free TRAM flaps often used many different qualitative measurements. Examples include ability to do sit-ups3 and the ability to get up from a supine position.14 One study found, not surprisingly, that a pedicled TRAM caused a significant loss of strength in the trunk.15 Just as the pedicled TRAM was refined to the free TRAM flap, this has been further developed into the MS-2. The MS-2 is an alternative to a DIEP flap, as the DIEP is dependent on the size, location and numbers of perforators. The free DIEP flap and free MS-2 TRAM flap (and the inconsistent SIEA flap) are the abdominal flaps causing the least donor site morbidity.16 It has been debated whether the advantages of the DIEP flap were sufficient to outweigh the longer operating times and increased flow related risks also associated with the procedure. Reconstruction using a DIEP flap reduces the risk of abdominal bulge and herniation,17 but it is not known if DIEP flap reconstruction offers a superior alternative to the MS-2 with regards to the abdominal strength.13 Different methods of selecting patients for MS-2 or DIEP exists, some argue that if the patient has small and few perforators, a MS-2 might make a better option.5 In our department we routinely use both the MS-2 free TRAM flap and the DIEP flap and we have previously published our experience in using the two flaps for breast reconstruction.18 In this material we found that as our experience with the two flaps increased, our results with the two flaps became almost identical. The operating time and ischaemic times were the same for the two types of flap and the
Table 3 Abdominal muscle strength in peak torque and peak torque adjusted for body weight (BW)
Isometric Isometric/BW Concentric Concentric/BW Eccentric Eccentric/BW
TRAM (n Z 15)
DIEP (n Z 17)
p-Value
75.8 88.5 79.6 106.4 97.2 123.8
74.1 96.7 84.3 117.6 97.0 135.4
0.76 0.14 0.49 0.19 0.98 0.05
(4.4) (4.1) (4.8) (6.9) (4.8) (4.0)
(3.4) (3.4) (4.6) (4.2) (4.4) (4.0)
Values given as Peak torque (mean(SE)) Nm.
522 duration of hospital stay was also similar for the two groups, with a median of seven days. In a study comparing patients reconstructed with a MS-2 free TRAM flap or a DIEP flap, Nahabedian et al.13 found no significant differences in the ability of to perform sit-ups. Few quantitative studies of abdominal wall strength after reconstruction using a free MS-2 TRAM flap as compared with DIEP flap exists. Isokinetic dynamometry is a well-documented method to measure trunk strength.19 The first study to use isokinetic dynamometry to study the effects of breast reconstruction on abdominal strength focused on the differences between traditional, full muscle TRAM flaps and DIEP flaps.10 The study found a significant reduction in strength to flex and to rotate the upper trunk in the TRAM flap group compared to the DIEP flap group and concludes that the resection of the rectus muscle is responsible for the difference. The MS-2 TRAM flap represents a refinement compared with the full muscle TRAM flap described in Blondeel’s study.10 The volume of muscle removed during the MS-2 procedure is much smaller and the functional rectus muscle is still present in the abdominal muscle network. Therefore, the impact of the MS-2 TRAM procedure on the abdominal muscle strength should also be reduced, compared with the full muscle version. Using an isokinetic dynamometer, Futter et al.12 examined the difference in abdominal strength after breast reconstruction using a MS-2 TRAM or a DIEP flaps. They found that the TRAM group had a significant weakness of the abdominal flexors during eccentric and isometric contraction and back extensors muscles during eccentric contraction when compared to the DIEP group. The TRAM group was also found to suffer more from functional problems in the daily living. However, patients included in the study had been operated any time from 6 to 60 months before the examination, with a mean time since reconstruction of 41 months for the TRAM flaps and 19 months for the DIEP flaps.12 The TRAM flap group were also older than the DIEP flap group with a mean age of 49.8 vs. 46.8 years. Thus the DIEP flap patients had a shorter follow-up and were also younger than the TRAM group. This could explain the difference in abdominal strength. Since surgical technique develops over time, having patients operated in the same period of time would be ideal if conclusions regarding results are to be made. Our study, is the first to examine the abdominal strength after MS-2 TRAM or DIEP flap reconstruction, in a patient material with identical patient age and follow-up. Our goal was to compare the postoperative effect on abdominal strength after breast reconstruction with a MS-2 TRAM or a DIEP flap. The abdominal strength of the two groups was very comparable, without major benefits from one or the other. We found no significant difference in abdominal strength between the two flap groups at low to moderate work intensity but at greater work intensity (eccentric muscle strength) the patients who had a breast reconstruction using a DIEP flap had a small yet significant advantage over the patients reconstructed using a MS-2 TRAM flap. There was no significant difference in abdominal strength between the two flap groups at low to moderate work intensity (isometric/concentric). At the greatest work intensity (eccentric muscle strength) the patients
C.T. Bonde et al. reconstructed with a DIEP flap had a clinical small, but significant advantage over the patients reconstructed with a MS-2 TRAM flap. Thus, only under heavy exertion will a functional difference in abdominal strength between the two procedures become apparent.
Acknowledgement The L.F. Foghts Fund, The Sophus Jakobsen and wife Astrid Jakobsens Fund, The Danish Medical Association Research Fund/The Vibe A. Linholter Estate, The Jacob Madsen and wife Olga Madsens Foundation, The P.A. Messerschmidt and wife Fund, Direktør Eva & Henry Fraenkels Memorial Fund, Lily Benthine Lunds Fund of 01.06.78, The Oak Foundation and by the University of Copenhagen. The authors also wish to thank laboratory technician Inger Wa ¨tjen for invaluable help during measurement of abdominal muscle strength.
References 1. Schusterman MA, Kroll SS, Miller MJ, et al. The free transverse rectus abdominis musculocutaneous flap for breast reconstruction: one center’s experience with 211 consecutive cases. Ann Plast Surg 1994;32:234e41. 2. Nieminen T, Asko-Seljavaara S, Suominen E, et al. Free microvascular tram flaps: report of 185 breast reconstructions. Scand J Plast Reconstr Surg Hand Surg 1999;33:295e300. 3. Kroll SS, Schusterman MA, Reece GP, et al. Abdominal wall strength, bulging, and hernia after tram flap breast reconstruction. Plast Reconstr Surg 1995;96:616e9. 4. Galli A, Adami M, Berrino P, et al. Long-term evaluation of the abdominal wall competence after total and selective harvesting of the rectus abdominis muscle. Ann Plast Surg 1992;28: 409e13. 5. Nahabedian MY, Momen B, Galdino G, et al. Breast reconstruction with the free TRAM or DIEP flap: patient selection, choice of flap, and outcome. Plast Reconstr Surg 2002;110:466e75. 6. Nahabedian MY, Dooley W, Singh N, et al. Contour abnormalities of the abdomen after breast reconstruction with abdominal flaps: the role of muscle preservation. Plast Reconstr Surg 2002;109:91e101. 7. Allen RJ, Treece P. Deep inferior epigastric perforator flap for breast reconstruction. Ann Plast Surg 1994;32:32e8. 8. Blondeel PN. One hundred free DIEP flap breast reconstructions: a personal experience. Br J Plast Surg 1999;52:104e11. 9. Blondeel PN, Boeckx WD. Refinements in free flap breast reconstruction: the free bilateral deep inferior epigastric perforator flap anastomosed to the internal mammary artery. Br J Plast Surg 1994;47:495e501. 10. Blondeel N, Vanderstraeten GG, Monstrey SJ, et al. The donor site morbidity of free DIEP flaps and free TRAM flaps for breast reconstruction. Br J Plast Surg 1997;50:322e30. 11. Kroll SS. Fat necrosis in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps. Plast Reconstr Surg 2000;106:576e83. 12. Futter CM, Webster MH, Hagen S, et al. A retrospective comparison of abdominal muscle strength following breast reconstruction with a free TRAM or DIEP flap. Br J Plast Surg 2000; 53:578e83. 13. Nahabedian MY, Tsangaris T, Momen B. Breast reconstruction with the DIEP flap or the muscle-sparing (MS-2) free TRAM flap: is there a difference? Plast Reconstr Surg 2005;115: 436e44.
Abdominal strength after breast reconstruction 14. Mizgala CL, Hartrampf Jr CR, Bennett GK. Assessment of the abdominal wall after pedicled TRAM flap surgery: 5- to 7-year follow-up of 150 consecutive patients. Plast Reconstr Surg 1994;93:988e1002. 15. Dulin WA, Avila RA, Verheyden CN, et al. Evaluation of abdominal wall strength after TRAM flap surgery. Plast Reconstr Surg 2004;113:1662e5. 16. Arnez ZM, Khan U, Pogorelec D, et al. Rational selection of flaps from the abdomen in breast reconstruction to reduce donor site morbidity. Br J Plast Surg 1999;52:351e4.
523 17. Nahabedian MY, Momen B. Lower abdominal bulge after deep inferior epigastric perforator flap (DIEP) breast reconstruction. Ann Plast Surg 2005;54:124e9. 18. Bonde CT, Christensen DE, Elberg JJ. Ten years’ experience of free flaps for breast reconstruction in a Danish microsurgical centre: an audit. Scand J Plast Reconstr Surg Hand Surg 2006; 40:8e12. 19. Newton M, Waddell G. Trunk strength testing with iso-machines. Part 1: review of a decade of scientific evidence. Spine June 1, 1993;18:801e11.
Abdominal strength after breast reconstruction using a free abdominal flap* Christian T. Bonde a,*, Hans Lund b, Marie Fridberg a, Bente Danneskiold-Samsoe b, Jens J. Elberg a a
Department of Plastic Surgery and Burns Unit, Center of Head and Orthopedics, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark b Parker Institute, Frederiksberg Hospital, DK-2000 Frederiksberg, Denmark Received 29 May 2006; accepted 22 July 2006
KEYWORDS Breast reconstruction; Abdominal strength; DIEP; TRAM; Isokinetic dynamometer
Summary Background: Today, breast reconstruction with autologous tissue is most commonly done either as a free muscle sparring TRAM flap or as a DIEP flap. Studies of donor site morbidity have shown an advantage in using the DIEP flap. However, this procedure might also be associated with an increased risk of flow related complications and it is also thought to be more demanding and time consuming. A few studies have evaluated the abdominal wall strength after dissection of a TRAM flap or a DIEP flap. However, these studies do not distinguish between the various types of free TRAM flaps and they also compare TRAM procedures preformed in an early period to DIEP procedures done in a later period. Methods: We used an isokinetic dynamometer to measure concentric, eccentric and isometric abdominal muscle strength in 32 patients who had had a unilateral breast reconstruction with a free MS-2 (15) or a DIEP (17) flap in the year 2003. Results: No significant reduction in muscle strength was observed for concentric or isometric muscle strength. However, significant lower eccentric muscle strength was found in the TRAM compared to the DIEP group (p Z 0.05). There was no significant difference in abdominal strength between the two flap groups at low to moderate work intensity (isometric/concentric). At the greatest work intensity (eccentric muscle strength) the patients reconstructed with a DIEP flap had a clinical small, but significant advantage over the patients reconstructed with a MS-2 TRAM flap. ª 2006 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.
* Presented at the 2006 Annual Scientific meeting of the American Society for Reconstructive Microsurgery, Loews Ventana Canyon Resort, Tucson, AZ, USA. January 14e17, 2006. * Corresponding author. Tel.: þ45 35458963, þ45 32542333 (private); fax: þ45 35452667. E-mail address: [email protected] (C.T. Bonde).
1748-6815/$ - see front matter ª 2006 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.bjps.2006.07.003
520 The transverse rectus abdominis musculocutaneous (TRAM) flap was, for many years, the standard in autologous tissue breast reconstruction.1,2 However, harvesting the TRAM flap leads to weakening of the abdominal wall.3 This weakening can be reduced by using a muscle-sparing TRAM flap in which only a small medial part of the muscle is included in the flap.4 The muscle-sparing (MS) techniques have been classified and include the MS-0, MS-1, and MS-2 free TRAM flaps.5,6 The MS-2 free TRAM flap used in this study, where both the medial and the lateral are preserved, causes the least amount of damage to the abdominal integrity and is most similar to the deep inferior epigastric perforator flap (DIEP) (MS-3). During the last decade, the DIEP flap7e9 has been found to be a superior reconstructive option because of minimal donor site morbidity.8,10 The DIEP flap preserves the anterior rectus sheath and the integrity of the abdominis muscle and reduces the incidence of abdominal weakness, bulge and hernia. However, the DIEP procedure might also be associated with an increased risk of flow related complications such as venous congestion and fat necrosis.11 The DIEP flap procedure is also thought to be more technically demanding and the DIEP flap procedure takes longer time to perform due to the dissection of the perforators through the muscle. A few studies have evaluated the abdominal wall strength after dissection of a TRAM flap or a DIEP flap. However, these studies do not distinguish between the various types of free TRAM flaps and they also compare TRAM procedures preformed in an early period to DIEP procedures done in a later period. Not surprisingly, decreased abdominal wall strength has been found in the TRAM groups. Blondeel et al.10 used isokinetic dynamometry to examine the difference in abdominal strength after breast reconstruction using free, full muscle TRAM flaps and DIEP flaps. He found that the full muscle TRAM flap group had a significant reduction in the strength to flex and rotate the upper trunk compared to the DIEP flap group. Using isokinetic dynamometry, Futter found a significant difference in flexion strength during eccentric and isometric contraction between the DIEP flap group and the free MS-2 TRAM flap group.12 However, patients included were operated over a period of 5 years with an average time since reconstruction of 41 months for the TRAM group and 19 months for the DIEP group. In a recent study comparing reconstructions performed with a MS-2 free TRAM flap or a DIEP flap, Nahabedian found no significant difference in the ability of to perform sit-ups.13 However, patients included were operated over a period of 5 years with an average time since reconstruction of 41 months for the TRAM group and 19 months for the DIEP group. No study, using isokinetic dynamometry has examined patients operated in the same period of time and with the same follow-up period.
C.T. Bonde et al. Table 1 Mean (standard deviation, SD) age, weight, height, follow-up time, operating time and mean length of hospital
Age (years) Weight (kg) Height (cm) Follow-up time (months) Operating time (min) Length of hospital stay (days)
DIEP flaps (n Z 17)
MS-2 TRAM flaps (n Z 15)
54 70.8 166.6 24 351 7.4
53 73.3 167.1 24 344 7.5
(6.5) (11.1) (7.6) (3.1) (62.3) (1.0)
(8.9) (8.4) (7.3) (3.5) (80.5) (1.5)
15 patients had a breast reconstruction using a free MS-2 TRAM flap and 17 patients had a breast reconstruction using a free DIEP flap. The median age, follow-up time, operating time and median length of hospital stay were comparable in both groups (Table 1). All procedures were performed by the same microsurgical team consisting of three senior consultants and two microsurgical trainees. A DIEP flap reconstruction is performed if possible, but, due to being a training department, we chose to convert the procedure to a MS-2 if more than two perforators are required for the DIEP flap based on intra-operative clinical evaluation of flap perfusion. The sheath of the rectus muscle is sutured using polypropylene 2/0 (Prolene) and no mesh is used.
Abdominal muscle strength measurements To define the patient’s maximal muscle strength we used an isokinetic dynamometer (Biodex System 3, PRO, Biodex Medical System, NY, USA) (Fig. 1). The dynamometer is made from a motor that moves a test arm with a constant speed throughout the whole range of motion (ROM) and which registers the entire torque influencing the test arm. A computer is connected to the system. It collects torque, velocity and the ROM angle and thus indirectly registers the dynamic muscle power. The dynamometer is warmed up and calibrated on a daily basis before measuring.
Materials and methods Patient material All patients who had had a unilateral breast reconstruction with a free MS-2 or a DIEP flap in the year 2003 (n Z 43) were included. Thirty-two agrees to participate. Of these,
Figure 1 Abdominal muscle strength testing in the isokinetic dynamometer.
Abdominal strength after breast reconstruction Table 2
521
Types of muscle contraction
Effect
Used in
Isometric
Concentric
Eccentric
Generates tension, no movement
Contraction, muscle shortening
Muscle lengthens under tension
Trunk stability
Trunk flexion
Trunk flexion
Standing position
Trunk flexion, curl ups
Lifting, vacuum cleaning
Abdominal muscle strength was measured as concentric, eccentric and isometric muscle strength, in the mentioned order. Concentric activity of a muscle occurs when the muscle is contracting whilst simultaneously shortening. An example could be trunk flexion during curl ups. With eccentric muscle activity, the muscle lengthens in a controlled manner whilst simultaneously maintaining tension. This is the most demanding contraction type, used for example during vacuum cleaning and lifting. During an isometric muscle contraction, tension is generated within the muscle but no movement occurs. This is used in stabilizing the trunk, for example when in a standing position (Table 2). The standard test consists of three repetitions at 30 s1 for both concentric and eccentric and five repetitions for isometric muscle strength. The isometric test was performed at 105 flexion of the hip (position of mechanical advantage for rectus abdominis). All tests were performed in a sitting position. A trial run of three sub-maximal muscle contractions was given initially as a warm-up and to familiarize the patient with the dynamometer. Throughout each test, a maximal effort was strongly encouraged in a standardized manner (Fig. 1), and a 30-s rest was allowed between each test. If the coefficient of variance (CV%) between the three (concentric and eccentric) or five (isometric) tests were higher than 10%, the measurement was repeated. If the CV% still was above 10% the session with the lowest CV% was chosen. The best of three repetitions was chosen as maximal concentric or eccentric muscle strength (peak torque), and the best of five for isometric (peak torque).
Statistical analysis Muscle strength data were analysed both as peak torque and peak torque adjusted for body weight. A Student’s t-test was applied with 2a < 0.05 as level of significance.
Results The results from the measurements of the abdominal strength are presented in Table 3. No significant reduction in muscle strength was observed for concentric or isometric muscle strength, neither uncorrected nor corrected for body weight. However, a significant lower eccentric muscle strength was found in the TRAM group (n Z 15) compared to the DIEP group (n Z 17) (123.8 Nm vs. 135.4 Nm, p Z 0.05), but only after correction for body weight. A 95% confidence interval on the difference ranged from 23.2 Nm to 0.007 Nm.
Discussion The advantage of using DIEP flaps instead of TRAM flaps for breast reconstruction has been debated for years. Most of the research done on the abdominal wall strength has been qualitative with few objective measurements. Older studies, focusing on the differences between pedicled and free TRAM flaps often used many different qualitative measurements. Examples include ability to do sit-ups3 and the ability to get up from a supine position.14 One study found, not surprisingly, that a pedicled TRAM caused a significant loss of strength in the trunk.15 Just as the pedicled TRAM was refined to the free TRAM flap, this has been further developed into the MS-2. The MS-2 is an alternative to a DIEP flap, as the DIEP is dependent on the size, location and numbers of perforators. The free DIEP flap and free MS-2 TRAM flap (and the inconsistent SIEA flap) are the abdominal flaps causing the least donor site morbidity.16 It has been debated whether the advantages of the DIEP flap were sufficient to outweigh the longer operating times and increased flow related risks also associated with the procedure. Reconstruction using a DIEP flap reduces the risk of abdominal bulge and herniation,17 but it is not known if DIEP flap reconstruction offers a superior alternative to the MS-2 with regards to the abdominal strength.13 Different methods of selecting patients for MS-2 or DIEP exists, some argue that if the patient has small and few perforators, a MS-2 might make a better option.5 In our department we routinely use both the MS-2 free TRAM flap and the DIEP flap and we have previously published our experience in using the two flaps for breast reconstruction.18 In this material we found that as our experience with the two flaps increased, our results with the two flaps became almost identical. The operating time and ischaemic times were the same for the two types of flap and the
Table 3 Abdominal muscle strength in peak torque and peak torque adjusted for body weight (BW)
Isometric Isometric/BW Concentric Concentric/BW Eccentric Eccentric/BW
TRAM (n Z 15)
DIEP (n Z 17)
p-Value
75.8 88.5 79.6 106.4 97.2 123.8
74.1 96.7 84.3 117.6 97.0 135.4
0.76 0.14 0.49 0.19 0.98 0.05
(4.4) (4.1) (4.8) (6.9) (4.8) (4.0)
(3.4) (3.4) (4.6) (4.2) (4.4) (4.0)
Values given as Peak torque (mean(SE)) Nm.
522 duration of hospital stay was also similar for the two groups, with a median of seven days. In a study comparing patients reconstructed with a MS-2 free TRAM flap or a DIEP flap, Nahabedian et al.13 found no significant differences in the ability of to perform sit-ups. Few quantitative studies of abdominal wall strength after reconstruction using a free MS-2 TRAM flap as compared with DIEP flap exists. Isokinetic dynamometry is a well-documented method to measure trunk strength.19 The first study to use isokinetic dynamometry to study the effects of breast reconstruction on abdominal strength focused on the differences between traditional, full muscle TRAM flaps and DIEP flaps.10 The study found a significant reduction in strength to flex and to rotate the upper trunk in the TRAM flap group compared to the DIEP flap group and concludes that the resection of the rectus muscle is responsible for the difference. The MS-2 TRAM flap represents a refinement compared with the full muscle TRAM flap described in Blondeel’s study.10 The volume of muscle removed during the MS-2 procedure is much smaller and the functional rectus muscle is still present in the abdominal muscle network. Therefore, the impact of the MS-2 TRAM procedure on the abdominal muscle strength should also be reduced, compared with the full muscle version. Using an isokinetic dynamometer, Futter et al.12 examined the difference in abdominal strength after breast reconstruction using a MS-2 TRAM or a DIEP flaps. They found that the TRAM group had a significant weakness of the abdominal flexors during eccentric and isometric contraction and back extensors muscles during eccentric contraction when compared to the DIEP group. The TRAM group was also found to suffer more from functional problems in the daily living. However, patients included in the study had been operated any time from 6 to 60 months before the examination, with a mean time since reconstruction of 41 months for the TRAM flaps and 19 months for the DIEP flaps.12 The TRAM flap group were also older than the DIEP flap group with a mean age of 49.8 vs. 46.8 years. Thus the DIEP flap patients had a shorter follow-up and were also younger than the TRAM group. This could explain the difference in abdominal strength. Since surgical technique develops over time, having patients operated in the same period of time would be ideal if conclusions regarding results are to be made. Our study, is the first to examine the abdominal strength after MS-2 TRAM or DIEP flap reconstruction, in a patient material with identical patient age and follow-up. Our goal was to compare the postoperative effect on abdominal strength after breast reconstruction with a MS-2 TRAM or a DIEP flap. The abdominal strength of the two groups was very comparable, without major benefits from one or the other. We found no significant difference in abdominal strength between the two flap groups at low to moderate work intensity but at greater work intensity (eccentric muscle strength) the patients who had a breast reconstruction using a DIEP flap had a small yet significant advantage over the patients reconstructed using a MS-2 TRAM flap. There was no significant difference in abdominal strength between the two flap groups at low to moderate work intensity (isometric/concentric). At the greatest work intensity (eccentric muscle strength) the patients
C.T. Bonde et al. reconstructed with a DIEP flap had a clinical small, but significant advantage over the patients reconstructed with a MS-2 TRAM flap. Thus, only under heavy exertion will a functional difference in abdominal strength between the two procedures become apparent.
Acknowledgement The L.F. Foghts Fund, The Sophus Jakobsen and wife Astrid Jakobsens Fund, The Danish Medical Association Research Fund/The Vibe A. Linholter Estate, The Jacob Madsen and wife Olga Madsens Foundation, The P.A. Messerschmidt and wife Fund, Direktør Eva & Henry Fraenkels Memorial Fund, Lily Benthine Lunds Fund of 01.06.78, The Oak Foundation and by the University of Copenhagen. The authors also wish to thank laboratory technician Inger Wa ¨tjen for invaluable help during measurement of abdominal muscle strength.
References 1. Schusterman MA, Kroll SS, Miller MJ, et al. The free transverse rectus abdominis musculocutaneous flap for breast reconstruction: one center’s experience with 211 consecutive cases. Ann Plast Surg 1994;32:234e41. 2. Nieminen T, Asko-Seljavaara S, Suominen E, et al. Free microvascular tram flaps: report of 185 breast reconstructions. Scand J Plast Reconstr Surg Hand Surg 1999;33:295e300. 3. Kroll SS, Schusterman MA, Reece GP, et al. Abdominal wall strength, bulging, and hernia after tram flap breast reconstruction. Plast Reconstr Surg 1995;96:616e9. 4. Galli A, Adami M, Berrino P, et al. Long-term evaluation of the abdominal wall competence after total and selective harvesting of the rectus abdominis muscle. Ann Plast Surg 1992;28: 409e13. 5. Nahabedian MY, Momen B, Galdino G, et al. Breast reconstruction with the free TRAM or DIEP flap: patient selection, choice of flap, and outcome. Plast Reconstr Surg 2002;110:466e75. 6. Nahabedian MY, Dooley W, Singh N, et al. Contour abnormalities of the abdomen after breast reconstruction with abdominal flaps: the role of muscle preservation. Plast Reconstr Surg 2002;109:91e101. 7. Allen RJ, Treece P. Deep inferior epigastric perforator flap for breast reconstruction. Ann Plast Surg 1994;32:32e8. 8. Blondeel PN. One hundred free DIEP flap breast reconstructions: a personal experience. Br J Plast Surg 1999;52:104e11. 9. Blondeel PN, Boeckx WD. Refinements in free flap breast reconstruction: the free bilateral deep inferior epigastric perforator flap anastomosed to the internal mammary artery. Br J Plast Surg 1994;47:495e501. 10. Blondeel N, Vanderstraeten GG, Monstrey SJ, et al. The donor site morbidity of free DIEP flaps and free TRAM flaps for breast reconstruction. Br J Plast Surg 1997;50:322e30. 11. Kroll SS. Fat necrosis in free transverse rectus abdominis myocutaneous and deep inferior epigastric perforator flaps. Plast Reconstr Surg 2000;106:576e83. 12. Futter CM, Webster MH, Hagen S, et al. A retrospective comparison of abdominal muscle strength following breast reconstruction with a free TRAM or DIEP flap. Br J Plast Surg 2000; 53:578e83. 13. Nahabedian MY, Tsangaris T, Momen B. Breast reconstruction with the DIEP flap or the muscle-sparing (MS-2) free TRAM flap: is there a difference? Plast Reconstr Surg 2005;115: 436e44.
Abdominal strength after breast reconstruction 14. Mizgala CL, Hartrampf Jr CR, Bennett GK. Assessment of the abdominal wall after pedicled TRAM flap surgery: 5- to 7-year follow-up of 150 consecutive patients. Plast Reconstr Surg 1994;93:988e1002. 15. Dulin WA, Avila RA, Verheyden CN, et al. Evaluation of abdominal wall strength after TRAM flap surgery. Plast Reconstr Surg 2004;113:1662e5. 16. Arnez ZM, Khan U, Pogorelec D, et al. Rational selection of flaps from the abdomen in breast reconstruction to reduce donor site morbidity. Br J Plast Surg 1999;52:351e4.
523 17. Nahabedian MY, Momen B. Lower abdominal bulge after deep inferior epigastric perforator flap (DIEP) breast reconstruction. Ann Plast Surg 2005;54:124e9. 18. Bonde CT, Christensen DE, Elberg JJ. Ten years’ experience of free flaps for breast reconstruction in a Danish microsurgical centre: an audit. Scand J Plast Reconstr Surg Hand Surg 2006; 40:8e12. 19. Newton M, Waddell G. Trunk strength testing with iso-machines. Part 1: review of a decade of scientific evidence. Spine June 1, 1993;18:801e11.