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Published in: Hernia 1/2008

01-02-2008 | Original Article

Transinguinal preperitoneal repair with the Polysoft patch: prospective evaluation of recurrence and chronic pain

Authors: E. P. Pélissier, D. Blum, Ph. Ngo, O. Monek

Published in: Hernia | Issue 1/2008

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Abstract

Objective

The Polysoft patch was conceived to facilitate performance of the transinguinal preperitoneal patch method and combine the advantages of patch placement in the preperitoneal space and the open inguinal approach. The aim of this prospective study was to evaluate the rate of recurrence and chronic pain at midterm follow-up.

Methods

In a cohort of 200 hernia repairs involved in a prospective evaluation, midterm results of 171 cases operated on from 1 July 2004 to 31 December 2005 were assessed. The anesthesia was spinal in 136 (79.5%) cases, local in 26 (15.2%), and general in nine (5.3%). A questionnaire was sent to patients on 30 November 2006 asking about recurrence, chronic groin pain, and satisfaction.

Results

With a median follow-up of 21.9 months (11.6–29.4), 167 (97.7%) patients were evaluated, two were dead, and two were lost to follow-up. There were two (1.2%) recurrences that were reoperated on; both consisted of an indirect sac that protruded between the branches of the split patch. Eleven (6.6%) patients alleged the feeling of a foreign body, and 12 (7.2%) reported pain that occurred occasionally or upon effort but did not precent activity. In one case, the pain present before operation was unchanged, and in three cases, the pain could clearly be attributed to an origin other than the hernia repair. No case of pain that impaired activity was observed. With regard to results, 98.2% of patients were satisfied and 97.6% declared that they would adopt the same method in case they had to be operated on for another hernia.

Conclusion

These results suggest that the technique provides a low rate of recurrence and a low percentage of chronic pain that did not impair activity.
Literature
1.
go back to reference Klinge U, Junge K, Stumpf M (2003) Causes of recurrence after Lichtenstein tension-free hernioplasty. Hernia 7:100–101PubMedCrossRef Klinge U, Junge K, Stumpf M (2003) Causes of recurrence after Lichtenstein tension-free hernioplasty. Hernia 7:100–101PubMedCrossRef
2.
go back to reference Rives J, Lardennois B, Flament JB, Couvert G (1973) La pièce en tulle de Dacron, traitement de choix des hernies de l’aine de l’adulte. A propos de 183 cas. Chirurgie 99:564–575PubMed Rives J, Lardennois B, Flament JB, Couvert G (1973) La pièce en tulle de Dacron, traitement de choix des hernies de l’aine de l’adulte. A propos de 183 cas. Chirurgie 99:564–575PubMed
3.
go back to reference Schumpelick V, Arlt G (1996) Transinguinale präperitoneale netzplastik (TIPP) beim leistenbruch in lokalanaesthesie. Chirurg 67:419–424PubMed Schumpelick V, Arlt G (1996) Transinguinale präperitoneale netzplastik (TIPP) beim leistenbruch in lokalanaesthesie. Chirurg 67:419–424PubMed
4.
go back to reference Muldoon RL, Marchant K, Johnson DD, Yoder GG, Read RC, Hauer-Jensen M (2004) Lichtenstein versus anterior preperitoneal prosthetic mesh placement in open inguinal hernia repair: a prospective randomized trial. Hernia 8:98–103PubMedCrossRef Muldoon RL, Marchant K, Johnson DD, Yoder GG, Read RC, Hauer-Jensen M (2004) Lichtenstein versus anterior preperitoneal prosthetic mesh placement in open inguinal hernia repair: a prospective randomized trial. Hernia 8:98–103PubMedCrossRef
5.
go back to reference Pelissier EP (2006) Inguinal hernia: preperitoneal placement of a memory-ring patch by anterior approach. Preliminary experience. Hernia 10:248–252PubMedCrossRef Pelissier EP (2006) Inguinal hernia: preperitoneal placement of a memory-ring patch by anterior approach. Preliminary experience. Hernia 10:248–252PubMedCrossRef
6.
go back to reference Pelissier EP, Monek O, Blum D, Ngo Ph (2007) The Polysoft patch: prospective evaluation of feasibility, post-operative pain and recovery. Hernia 11:229–234PubMedCrossRef Pelissier EP, Monek O, Blum D, Ngo Ph (2007) The Polysoft patch: prospective evaluation of feasibility, post-operative pain and recovery. Hernia 11:229–234PubMedCrossRef
7.
go back to reference Arvidsson D, Smedberg S (2000) Laparoscopic compared with open hernia surgery: complications, recurrences and current trials. Eur J Surg 585:40–47 Arvidsson D, Smedberg S (2000) Laparoscopic compared with open hernia surgery: complications, recurrences and current trials. Eur J Surg 585:40–47
8.
go back to reference Grant AM (2002) Laparoscopic versus open groin hernia repair: meta-analysis of randomised trials based on individual patients data. Hernia 6:2–10PubMedCrossRef Grant AM (2002) Laparoscopic versus open groin hernia repair: meta-analysis of randomised trials based on individual patients data. Hernia 6:2–10PubMedCrossRef
9.
go back to reference Grant AM (2002) Open mesh versus non-mesh repair of groin hernia meta-analysis of randomized trials based on individual patient data. Hernia 6:130–136PubMedCrossRef Grant AM (2002) Open mesh versus non-mesh repair of groin hernia meta-analysis of randomized trials based on individual patient data. Hernia 6:130–136PubMedCrossRef
10.
go back to reference Amid PK, Shulman AG, Lichtenstein IL (1996) Open "tension-free" repair of inguinal hernias: the Lichtenstein technique. Eur J Surg 162:447–453PubMed Amid PK, Shulman AG, Lichtenstein IL (1996) Open "tension-free" repair of inguinal hernias: the Lichtenstein technique. Eur J Surg 162:447–453PubMed
11.
go back to reference Bringman S, Ramie S, Heikkinen TJ, Englund T, Westman B, Anderberg B (2003) Tension-free inguinal hernia repair: TEP versus mesh-plug versus Lichtenstein. A prospective randomized controlled trial. Ann Surg 237:142–147PubMedCrossRef Bringman S, Ramie S, Heikkinen TJ, Englund T, Westman B, Anderberg B (2003) Tension-free inguinal hernia repair: TEP versus mesh-plug versus Lichtenstein. A prospective randomized controlled trial. Ann Surg 237:142–147PubMedCrossRef
12.
go back to reference Friis E, Lindahl F (1996) The tension-free hernioplasty in a randomized trial. Am J Surg 172:315–319PubMedCrossRef Friis E, Lindahl F (1996) The tension-free hernioplasty in a randomized trial. Am J Surg 172:315–319PubMedCrossRef
13.
go back to reference Kama NA, Reis E, Atli MY, Doganay M, Güler M, Kologlu M, Dolapçi M (2000) Factors affecting recurrence in tension-free hernioplasties. Hernia 4:17–20CrossRef Kama NA, Reis E, Atli MY, Doganay M, Güler M, Kologlu M, Dolapçi M (2000) Factors affecting recurrence in tension-free hernioplasties. Hernia 4:17–20CrossRef
14.
go back to reference Paajanen H (2002) Do absorbable mesh sutures cause less chronic pain than nonabsorbable sutures after Lichtenstein inguinal herniorrhaphy? Hernia 6:26–28PubMedCrossRef Paajanen H (2002) Do absorbable mesh sutures cause less chronic pain than nonabsorbable sutures after Lichtenstein inguinal herniorrhaphy? Hernia 6:26–28PubMedCrossRef
15.
go back to reference Neumayer L, Globbie-Hurder A, Jonasson O, Fitzgibbons R, Dunlop D, Gibbs J, Reda D, Henderson W (2004) Open mesh versus laparoscopic mesh repair of inguinal hernia. N Engl J Med 350:1819–1827PubMedCrossRef Neumayer L, Globbie-Hurder A, Jonasson O, Fitzgibbons R, Dunlop D, Gibbs J, Reda D, Henderson W (2004) Open mesh versus laparoscopic mesh repair of inguinal hernia. N Engl J Med 350:1819–1827PubMedCrossRef
16.
go back to reference Bringman S, Wollert S, Osterberg J, Smedberg S, Granlund H, Heikkinen TJ (2006) Three-year results of a randomized clinical trial of lightweight or standard polypropylene mesh in Lichtenstein repair of primary inguinal hernia. Br J Surg 93:1056–1059PubMedCrossRef Bringman S, Wollert S, Osterberg J, Smedberg S, Granlund H, Heikkinen TJ (2006) Three-year results of a randomized clinical trial of lightweight or standard polypropylene mesh in Lichtenstein repair of primary inguinal hernia. Br J Surg 93:1056–1059PubMedCrossRef
17.
go back to reference Pelissier EP, Blum D, Damas JM, Marre P (1999) The plug method in inguinal hernia: a prospective evaluation. Hernia 4:201–204CrossRef Pelissier EP, Blum D, Damas JM, Marre P (1999) The plug method in inguinal hernia: a prospective evaluation. Hernia 4:201–204CrossRef
18.
go back to reference Zdolsek JM, Enebog J, Wallon C, Kald A (2000) A prospective evaluation of the PerFix plug technique for groin hernia repair. Hernia 4:311–315CrossRef Zdolsek JM, Enebog J, Wallon C, Kald A (2000) A prospective evaluation of the PerFix plug technique for groin hernia repair. Hernia 4:311–315CrossRef
19.
go back to reference Witkowski P, Pirski MI, Adamonis W, Smietanski M, Draczkowski T, Sledzinski Z (2000) Mesh-plug versus Bassini operation: a randomized prospective study. Hernia 4:305–310CrossRef Witkowski P, Pirski MI, Adamonis W, Smietanski M, Draczkowski T, Sledzinski Z (2000) Mesh-plug versus Bassini operation: a randomized prospective study. Hernia 4:305–310CrossRef
20.
go back to reference Nienhuijs SW, van Oort I, Keemers-Gel ME, Strobbe LJA, Rosman C (2005) Randomized clinical trial comparing the prolene hernia system, mesh plug repair and Lichtenstein method for open inguinal hernia repair. Br J Surg 92:33–38PubMedCrossRef Nienhuijs SW, van Oort I, Keemers-Gel ME, Strobbe LJA, Rosman C (2005) Randomized clinical trial comparing the prolene hernia system, mesh plug repair and Lichtenstein method for open inguinal hernia repair. Br J Surg 92:33–38PubMedCrossRef
21.
go back to reference Occeli G, Barrat C, Catheline JM, Voreux JP, Cueto-Rozon R, Champault G (2000) Laparoscopic treatment of inguinal hernias: prospective evaluation of 757 cases treated by a totally extraperitoneal route. Hernia 4:81–84CrossRef Occeli G, Barrat C, Catheline JM, Voreux JP, Cueto-Rozon R, Champault G (2000) Laparoscopic treatment of inguinal hernias: prospective evaluation of 757 cases treated by a totally extraperitoneal route. Hernia 4:81–84CrossRef
22.
go back to reference Lau H (2005) Fibrin sealant versus mechanical stapling for mesh fixation during endoscopic extraperitoneal inguinal hernioplasty: a randomized prospective trial. Ann Surg 242:670–675PubMedCrossRef Lau H (2005) Fibrin sealant versus mechanical stapling for mesh fixation during endoscopic extraperitoneal inguinal hernioplasty: a randomized prospective trial. Ann Surg 242:670–675PubMedCrossRef
23.
go back to reference Alani A, Duffy F, O’Dwyer PJ (2006) Laparoscopic or open preperitoneal repair in the management of recurrent groin hernias. Hernia 10:156–158PubMedCrossRef Alani A, Duffy F, O’Dwyer PJ (2006) Laparoscopic or open preperitoneal repair in the management of recurrent groin hernias. Hernia 10:156–158PubMedCrossRef
24.
go back to reference ChampaultG, Rizk N, Catheline JM, Barrat C, Turner R, Boutelier P (1997) Inguinal hernia repair. Totally preperitoneal laparoscopic approach versus Stoppa operation. Randomized trial: 100 cases. Hernia 1:31–36CrossRef ChampaultG, Rizk N, Catheline JM, Barrat C, Turner R, Boutelier P (1997) Inguinal hernia repair. Totally preperitoneal laparoscopic approach versus Stoppa operation. Randomized trial: 100 cases. Hernia 1:31–36CrossRef
25.
go back to reference Leroy J, Barthelemy R (1997) Laparoscopic repair of inguinal hernias with wide prosthesis using Stoppa’s principles: analysis of 920 sites operated in 800 patients. Hernia 1:131–138CrossRef Leroy J, Barthelemy R (1997) Laparoscopic repair of inguinal hernias with wide prosthesis using Stoppa’s principles: analysis of 920 sites operated in 800 patients. Hernia 1:131–138CrossRef
26.
go back to reference Knook MTT, Weidema WF, Stassen LPS, Borlhouwer RU, van Steensel CJ (1999) Endoscopic totally extraperitoneal repair of bilateral inguinal hernias. Br J Surg 86:1312–1316PubMedCrossRef Knook MTT, Weidema WF, Stassen LPS, Borlhouwer RU, van Steensel CJ (1999) Endoscopic totally extraperitoneal repair of bilateral inguinal hernias. Br J Surg 86:1312–1316PubMedCrossRef
27.
go back to reference Leibl BJ, Däubler P, Schmedt CG, Kraft K, Bittner R (2000) Long-term results of a randomized clinical trial between laparoscopic hernioplasty and Shouldice repair. Br J Surg 87:780–783PubMedCrossRef Leibl BJ, Däubler P, Schmedt CG, Kraft K, Bittner R (2000) Long-term results of a randomized clinical trial between laparoscopic hernioplasty and Shouldice repair. Br J Surg 87:780–783PubMedCrossRef
28.
go back to reference Bobrzynski A, Budzynski A, Biesiada Z, Kowalczyk M, Lubikowski J, Sienko J (2001) Experience––the key factor in successful laparoscopic total extraperitoneal and transabdominal preperitoneal hernia repair. Hernia 5:80–83PubMedCrossRef Bobrzynski A, Budzynski A, Biesiada Z, Kowalczyk M, Lubikowski J, Sienko J (2001) Experience––the key factor in successful laparoscopic total extraperitoneal and transabdominal preperitoneal hernia repair. Hernia 5:80–83PubMedCrossRef
29.
go back to reference Vo Huu Le J, Buffler A, Rohr S, Bertoncello L, Meyer C (2001) Long-term recurrences after laparoscopic surgery of inguinal hernias. Hernia 5:88–91PubMedCrossRef Vo Huu Le J, Buffler A, Rohr S, Bertoncello L, Meyer C (2001) Long-term recurrences after laparoscopic surgery of inguinal hernias. Hernia 5:88–91PubMedCrossRef
30.
31.
go back to reference Berndsen F, Petersson U, Montgomery A (2002) Endoscopic repair of bilateral inguinal hernias-short and late outcome. Hernia 5:192–195 Berndsen F, Petersson U, Montgomery A (2002) Endoscopic repair of bilateral inguinal hernias-short and late outcome. Hernia 5:192–195
32.
go back to reference Sinha R, Sharma N, Dhobal D, Joshi M (2006) Laparoscopic total extraperitoneal repair versus anterior preperitoneal repair for inguinal hernia. Hernia 10:187–191PubMedCrossRef Sinha R, Sharma N, Dhobal D, Joshi M (2006) Laparoscopic total extraperitoneal repair versus anterior preperitoneal repair for inguinal hernia. Hernia 10:187–191PubMedCrossRef
33.
go back to reference Nutley MT, Mulloy RH, Hagen N (2006) Minimal post-operative pain using properitoneal nontension sutured repair of direct inguinal hernias. Am J Surg 191:479–482PubMedCrossRef Nutley MT, Mulloy RH, Hagen N (2006) Minimal post-operative pain using properitoneal nontension sutured repair of direct inguinal hernias. Am J Surg 191:479–482PubMedCrossRef
34.
go back to reference Bay-Nielsen M, Nordin P, Nilsson E, Kehlet H (2001) Operative findings in recurrent hernia after a Lichtenstein procedure. Am J Surg 182:134–136PubMedCrossRef Bay-Nielsen M, Nordin P, Nilsson E, Kehlet H (2001) Operative findings in recurrent hernia after a Lichtenstein procedure. Am J Surg 182:134–136PubMedCrossRef
35.
go back to reference Lowham AS, Filipi CJ, Fitzgibbons RJ, Stoppa RE, Wantz GE, Felix EL, Crafton WB (1997) Mechanisms of hernia recurrence after preperitoneal mesh repair. Ann Surg 225:422–431PubMedCrossRef Lowham AS, Filipi CJ, Fitzgibbons RJ, Stoppa RE, Wantz GE, Felix EL, Crafton WB (1997) Mechanisms of hernia recurrence after preperitoneal mesh repair. Ann Surg 225:422–431PubMedCrossRef
36.
go back to reference Celdran A, Frieyro O, Souto JL, Villar S (2000) Study of recurrences after anterior open tension-free hernioplasty. Hernia 4:85–87CrossRef Celdran A, Frieyro O, Souto JL, Villar S (2000) Study of recurrences after anterior open tension-free hernioplasty. Hernia 4:85–87CrossRef
37.
go back to reference Amid PK (2003) The Lichtenstein repair in 2002: an overview of causes of recurrence after Lichtenstein tension-free hernioplasty. Hernia 7:13–16PubMedCrossRef Amid PK (2003) The Lichtenstein repair in 2002: an overview of causes of recurrence after Lichtenstein tension-free hernioplasty. Hernia 7:13–16PubMedCrossRef
38.
go back to reference Cunningham J, Temple W, Mitchell P, Nixon JA, Preshaw RM, Hagen NA (1996) Cooperative hernia study: pain in the postrepair patient. Ann Surg 224:598–602PubMedCrossRef Cunningham J, Temple W, Mitchell P, Nixon JA, Preshaw RM, Hagen NA (1996) Cooperative hernia study: pain in the postrepair patient. Ann Surg 224:598–602PubMedCrossRef
39.
go back to reference Gillion JF, Fagniez PL (1999) Chronic pain and cutaneous sensory changes after inguinal hernia repair: comparison between open and laparoscopic techniques. Hernia 3:75–80CrossRef Gillion JF, Fagniez PL (1999) Chronic pain and cutaneous sensory changes after inguinal hernia repair: comparison between open and laparoscopic techniques. Hernia 3:75–80CrossRef
40.
go back to reference Callesen T, Bech K, Kehlet H (1999) Prospective study of chronic pain after groin hernia repair. Br J Surg 86:1528–1531PubMedCrossRef Callesen T, Bech K, Kehlet H (1999) Prospective study of chronic pain after groin hernia repair. Br J Surg 86:1528–1531PubMedCrossRef
41.
go back to reference Poobalan AS, Bruce J, King PM, Chambers WA, Krukowski ZH, Smith WCS (2001) Chronic pain and quality of life following open inguinal hernia repair. Br J Surg 88:1122–1126PubMedCrossRef Poobalan AS, Bruce J, King PM, Chambers WA, Krukowski ZH, Smith WCS (2001) Chronic pain and quality of life following open inguinal hernia repair. Br J Surg 88:1122–1126PubMedCrossRef
42.
go back to reference Kumar S, Wilson RG, Nixon SJ, Macintyre MC (2002) Chronic pain after laparoscopic and open mesh repair of groin hernia. Br J Surg 89:1476–1479PubMedCrossRef Kumar S, Wilson RG, Nixon SJ, Macintyre MC (2002) Chronic pain after laparoscopic and open mesh repair of groin hernia. Br J Surg 89:1476–1479PubMedCrossRef
43.
go back to reference Bay-Nielsen M, Nilsson E, Nordin P, Kehlet H, the Swedish Hernia Data Base (2004) Chronic pain after open mesh and sutured repair of indirect inguinal hernia in young males. Br J Surg 91:1372–1376 Bay-Nielsen M, Nilsson E, Nordin P, Kehlet H, the Swedish Hernia Data Base (2004) Chronic pain after open mesh and sutured repair of indirect inguinal hernia in young males. Br J Surg 91:1372–1376
44.
go back to reference O’Dwyer PJ, Kingsnorth AN, Molloy RG, Small PK, Lammers B, Horeyseck G (2005) Randomized clinical trial assessing impact of a lightweight or heavyweight mesh on chronic pain after inguinal hernia repair. Br J Surg 92:166–170PubMedCrossRef O’Dwyer PJ, Kingsnorth AN, Molloy RG, Small PK, Lammers B, Horeyseck G (2005) Randomized clinical trial assessing impact of a lightweight or heavyweight mesh on chronic pain after inguinal hernia repair. Br J Surg 92:166–170PubMedCrossRef
45.
go back to reference Sanjay P, Harris D, Jones P, Woodward A (2006) Randomized controlled trial comparing Prolene hernia system and Lichtenstein method for inguinal hernia repair. ANZ J Surg 76:548–552PubMedCrossRef Sanjay P, Harris D, Jones P, Woodward A (2006) Randomized controlled trial comparing Prolene hernia system and Lichtenstein method for inguinal hernia repair. ANZ J Surg 76:548–552PubMedCrossRef
46.
go back to reference Franneby U, Sandblom G, Nordin P, Nyren O, Gunnarsson U (2006) Risk factors for long-term pain after hernia surgery. Ann Surg 244:212–219PubMedCrossRef Franneby U, Sandblom G, Nordin P, Nyren O, Gunnarsson U (2006) Risk factors for long-term pain after hernia surgery. Ann Surg 244:212–219PubMedCrossRef
47.
go back to reference Heikkinen T, Bringman S, Ohtonen P, Kunelius P, Haukipuro K, Hulkko A (2004) Five-year outcome of laparoscopic and Lichtenstein hernioplasties. Surg Endosc 18:518–522PubMedCrossRef Heikkinen T, Bringman S, Ohtonen P, Kunelius P, Haukipuro K, Hulkko A (2004) Five-year outcome of laparoscopic and Lichtenstein hernioplasties. Surg Endosc 18:518–522PubMedCrossRef
48.
go back to reference Grant AM, Scott NW, O’Dwyer PJ, on behalf of the MRC Laparoscopic Groin Hernia Trial Group (2004) Five-year follow-up of a randomized trial to assess pain and numbness after laparoscopic or open repair of groin hernia. Br J Surg 91:1570–1574 Grant AM, Scott NW, O’Dwyer PJ, on behalf of the MRC Laparoscopic Groin Hernia Trial Group (2004) Five-year follow-up of a randomized trial to assess pain and numbness after laparoscopic or open repair of groin hernia. Br J Surg 91:1570–1574
49.
go back to reference Schmedt CG, Sauerland S, Bittner R (2005) Comparison of endoscopic procedures versus Lichtenstein and other open mesh techniques for inguinal hernia repair: a meta-analysis of randomized controlled trials. Surg Endosc 19:189–199CrossRef Schmedt CG, Sauerland S, Bittner R (2005) Comparison of endoscopic procedures versus Lichtenstein and other open mesh techniques for inguinal hernia repair: a meta-analysis of randomized controlled trials. Surg Endosc 19:189–199CrossRef
50.
go back to reference Lau H, Patil NG, Yuen WK (2006) Day-case endoscopic totally extraperitoneal inguinal hernioplasty versus open Lichtenstein hernioplasty for unilateral primary inguinal hernia in males: a randomized trial. Surg Endosc 20:76–81PubMedCrossRef Lau H, Patil NG, Yuen WK (2006) Day-case endoscopic totally extraperitoneal inguinal hernioplasty versus open Lichtenstein hernioplasty for unilateral primary inguinal hernia in males: a randomized trial. Surg Endosc 20:76–81PubMedCrossRef
51.
go back to reference Demirer S, Kepenekci I, Evirgen O, Birsen O, Tuzuner A, Karahuseyinoglu S, Ozban M, Kuterdem E (2006) The effect of polypropylene mesh on ilioinguinal nerve in open mesh repair of groin hernia. J Surg Res 131:175–181PubMedCrossRef Demirer S, Kepenekci I, Evirgen O, Birsen O, Tuzuner A, Karahuseyinoglu S, Ozban M, Kuterdem E (2006) The effect of polypropylene mesh on ilioinguinal nerve in open mesh repair of groin hernia. J Surg Res 131:175–181PubMedCrossRef
Metadata
Title
Transinguinal preperitoneal repair with the Polysoft patch: prospective evaluation of recurrence and chronic pain
Authors
E. P. Pélissier
D. Blum
Ph. Ngo
O. Monek
Publication date
01-02-2008
Publisher
Springer-Verlag
Published in
Hernia / Issue 1/2008
Print ISSN: 1265-4906
Electronic ISSN: 1248-9204
DOI
https://doi.org/10.1007/s10029-007-0278-4

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