Permanent implantation of expanded polytetrafluoroethylene is safe for pelvic surgery*

B.S. Hurst1 for the United States Expanded Polytetrafluoroethylene Reproductive Surgery Study Group§

Department of Obstetrics and Gynecology, University of Colorado Health Sciences Center, Denver, Colorado, USA


    Abstract
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Clinical trials have shown the expanded polytetrafluoroethylene (ePTFE) membrane to be a highly effective adhesion barrier in gynaecological reconstructive surgery, but the material has not gained wide acceptance because of uncertainty about long-term safety. We conducted a prospective, observational multicentre study to determine if permanent implantation of the ePTFE membrane in the pelvis caused any adverse effects. The subjects were 146 women in whom the membrane was implanted permanently during peritoneal reconstruction in 1991–1996. Postoperatively, patients were examined at regular intervals. The mean postoperative observation time was 3.5 years. No long-term complications occurred. There were 10 births by Caesarean section and 12 by vaginal delivery. All of the pregnancies before these 22 births were uneventful, including 10 in which the women had uterine implantation sites. There were two ectopic pregnancies and three spontaneous abortions. Since the primary purpose of the study was to evaluate the long-term safety of ePTFE, early second-look laparoscopy was not performed routinely. Nevertheless, 24 women had a subsequent operation. Adhesions were present at 8/21 of the membrane sites in these women, a significant decrease compared with adhesions at 17/21 sites during the initial procedure (P = 0.005). This large, multicentre study confirmed the long-term safety of the ePTFE membrane in pelvic reconstruction. Removal of the barrier is not necessary.

Key words: adhesions/expanded polytetrafluoroethylene/pelvis/reproductive surgery/surgical barriers


    Introduction
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Clinical trials have shown the expanded polytetrafluoroethylene (ePTFE) membrane (PRECLUDE Peritoneal Membrane®; W.L. Gore and Associates Inc., Flagstaff, AZ, USA) to be the most effective adhesion barrier in gynaecological reconstructive surgery (Surgical Membrane Study Group, 1992Go; Haney et al., 1995Go; Myomectomy Adhesion Multicenter Group, 1995Go). In a prospective, randomized clinical trial (Haney et al., 1995Go), the ePTFE membrane was significantly more effective at reducing adhesions on the pelvic sidewall than oxidized regenerated cellulose (Interceed TC7®; Johnson & Johnson Medical Inc., Arlington, TX, USA). The ePTFE membrane was also found to be an effective barrier for the prevention of uterine adhesions after myomectomy (Surgical Membrane Study Group, 1992Go).

Despite its proven efficacy, use of the ePTFE membrane to prevent pelvic adhesions has not gained wide acceptance. The reasons for slow acceptance of this adhesion barrier are not clear, but may be due to concerns about ease of use or uncertainty about long-term safety. A multicentre study found that the ePTFE membrane was easy to use and increased surgical time by <11 min when staples were used to anchor the device during laparoscopic surgery (Crain et al., 1995Go). Long-term safety of the ePTFE membrane has been established in thoracic surgery and neurosurgery (Inoue et al., 1984; Jacobs et al., 1996Go). However, no previous studies have confirmed long-term safety of the ePTFE membrane in pelvic surgery. Therefore the goal of this study was to determine whether permanent implantation of the membrane in the pelvis to prevent adhesions was associated with any adverse events.


    Materials and methods
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
In a multicentre study, we collected prospective, observational data on patients in whom an ePTFE peritoneal membrane was implanted permanently in the pelvis in 1991–1996 to prevent adhesions. Informed consent was obtained before surgery, and a wide range of reconstructive surgical procedures was performed. All operative laparoscopic and open laparotomy cases in which the ePTFE adhesion barrier was used were included in the data collection. The membrane was used at the discretion of the surgeon and was implanted in uterine, pelvic sidewall, and posterior cul-de-sac sites. During the procedure, the implantation site was assessed for the presence of adhesions.

The manufacturer's guidelines for use of ePTFE membrane were followed. Prophylactic antibiotic therapy was administered routinely. The membrane was placed to cover the defect and overlap the edges by >=1 cm, when possible. The membrane was implanted to lie as flat as possible, and at least one permanent anchoring suture or staple was used. Additional permanent or absorbable sutures or staples were used at the discretion of the surgeon.

Postoperatively, patients were examined routinely. Clinical follow-up assessments included recording of any adverse event possibly related to implantation of the membrane, e.g. infection. Pregnancy outcome was recorded. In patients who underwent subsequent surgery, the membrane implantation site was evaluated for the presence of pelvic adhesions.

Standard forms were completed for each patient visit and surgical procedure and sent to a central registry for data analysis. In patients who underwent subsequent surgery, the difference between the presence of adhesions at the initial and the subsequent surgical procedure was compared with the {chi}2 test. A P value <= 0.05 was considered significant.


    Results
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 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Characteristics of the subjects are shown in Table IGo. One hundred forty-six women with a mean age of 34 years at the time of initial surgery (range 21–44 years) were enrolled in the study. Fifty-eight had an operative laparoscopic procedure and 88 underwent open laparotomy. Myomectomy was the single most common primary procedure (59 patients), but a total of 71 patients had lysis of adnexal adhesions. Ovarian, tubal, or uterine reconstruction was the primary procedure in most of the remaining subjects. The uterus was the most common site of implantation of the ePTFE membrane.


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Table I. Characteristics of 146 women in whom an expanded polytetrafluoroethylene (ePTFE) membrane was implanted
 
There was one short-term complication: an infection that occurred in the immediate postoperative period. The infection was managed with antibiotic therapy and did not necessitate removal of the membrane. No other perioperative complications were observed. In addition, during mean postoperative follow-up of 3.5 years (range 3.7 months to 5.7 years), no adverse events due to the ePTFE membrane were recorded for any patient during routine clinical follow-up visits.

Thirty-two patients became pregnant after their initial surgical procedure (Table IIGo). Two ectopic pregnancies occurred in women in whom the membrane had been placed in the sidewall after adhesiolysis. Three women had first-trimester spontaneous abortions requiring dilatation and curettage; in each, the membrane had been implanted on the uterus. There were 12 vaginal deliveries, two by women with a uterine implantation site. There were 10 deliveries by Caesarean section, eight in women with uterine implantation sites. Four pregnancies are ongoing. The course of all pregnancies that have progressed beyond the first trimester was uneventful, including 10 women who had a uterine implantation site. One women with a cul-de-sac implantation site delivered a stillborn infant. The stillbirth was attributed to a nuchal cord, and there did not appear to be any relation to use of the ePTFE membrane. No complications were noted at the time of Caesarean section in the eight women in whom the ePTFE membrane was implanted on the uterus. There were no obstetric complications that could be attributed to the ePTFE membrane.


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Table II. Outcome data in 146 women in whom an expanded polytetrafluoroethylene (ePTFE) membrane was implanted
 
Early second-look laparoscopy was not performed routinely in this series, but 24 patients underwent a subsequent surgical procedure (Table IIGo). The mean time between the first and second surgical procedure was 322 days (range 15 days to >3 years). During the subsequent surgical procedure, adhesions were observed in eight of the 21 membrane implantation sites assessed. This represented a significant (P = 0.005) decrease in the number of sites with adhesions at the initial procedure (17 of 21) in the same women. No complications attributed to the ePTFE membrane were noted in any patient at the time of subsequent surgery.


    Discussion
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Our study confirms the long-term safety of the ePTFE peritoneal membrane and provides further data in support of the efficacy of this adhesion barrier. We did not identify a single adverse effect associated with permanent implantation of the membrane in more than 507 patient-years of observation. There was no apparent relationship between ectopic pregnancies, spontaneous abortion, or infection, and the ePTFE membrane. The ectopic pregnancies occurred in two women with tubo-ovarian adhesions, a recognized risk factor for tubal implantation. It is unlikely that an extratubal ePTFE site would alter intratubal gamete transport and increase the risk of tubal pregnancy. It is even more unlikely that placement of the ePTFE barrier on the uterine serosa would increase the risk of spontaneous abortion. In fact, the 9% spontaneous abortion rate seen in this study was slightly below the normally reported rate of 10–20%. A postoperative infection is usually considered to be more serious in the presence of a foreign object, but our patient with such an infection responded to antibiotic treatment without removal of the ePTFE membrane. In summary, observational data indicate that it is highly unlikely that the ePTFE peritoneal membrane will produce any long-term adverse effects.

Assessment of the efficacy of the ePTFE membrane was not a goal of the study, since the effectiveness of this device in pelvic surgery was demonstrated clearly in earlier studies. In theory, the ePTFE membrane mechanically separates traumatized peritoneal surfaces, and allows each to heal without forming adhesions. Histological examination of the ePTFE membrane removed after second-look laparoscopy demonstrated no tissue attachment in a previous report (Haney et al., 1995Go). A preliminary clinical study found a dramatic reduction in adhesion reformation with use of the ePTFE membrane that was far superior to results obtained with other anti-adhesion agents (Surgical Membrane Study Group, 1992Go). In a prospective, randomized clinical study, ePTFE membrane significantly reduced myomectomy site adhesions at the uterine fundus and posterior uterus in comparison with results achieved with microsurgery alone (Myomectomy Adhesion Multicenter Study Group, 1995). Another prospective, randomized clinical trial found that the ePTFE membrane was significantly more effective than oxidized regenerated cellulose for prevention of pelvic sidewall adhesions (Haney et al., 1995Go).

Despite the strong evidence of its safety and efficacy, the ePTFE peritoneal membrane is underused in pelvic surgery. An estimated 8000 myomectomies are performed in the USA each year (Golan, 1996Go). Adhesions to the uterine fundus and posterior portion of the uterus may occur in over 90% of incision sites after myomectomy (Tulandi et al., 1993Go; Myomectomy Adhesion Multicenter Group, 1995Go; Diamond et al., 1996Go). An absorbable membrane composed of sodium hyaluronate and carboxymethylcellulose (Seprafilm®; Genzyme Corporation, Cambridge, MA, USA) did not significantly decrease formation of posterior uterine adhesions after myomectomy, although adhesions to the anterior uterine surface were reduced (Diamond et al., 1996Go). However, 65% of women in whom this absorbable membrane was implanted were later found to have adhesions between the posterior uterus and large bowel after myomectomy. In addition, in more than 90% of women adnexal adhesions may form after a posterior uterine myomectomy (Tulandi et al., 1993Go). With respect to oxidized regenerated cellulose, serious concerns have been raised about its use in a site that is not completely haemostatic (Linsky et al., 1988Go). Thus, its use in myomectomies is not advisable.

In contrast, despite the propensity of the uterine fundus and posterior uterus to form adhesions, more than 55% of myomectomy incisions at these sites were completely free of adhesions when the ePTFE membrane was used as an adhesion barrier (Myomectomy Adhesion Multicenter Group, 1995Go). Annual use of more than 10 000 ePTFE peritoneal membranes could be justified for this indication alone. However, this adhesion barrier is probably used far less often, and most surgeons who perform myomectomies probably do not use this device.

In conclusion, our large multicentre study confirmed the long-term safety of use of the ePTFE peritoneal membrane to reduce adhesions after pelvic reconstruction. No complications associated with the adhesion barrier were observed at any follow-up visits, and no obstetrical problems associated with the ePTFE membrane were identified, even in women in whom the device was implanted on the uterus. Furthermore, no membrane-related problems were observed in patients who had subsequent surgery, and a significant reduction in adhesion formation was found in this group. Our findings support the routine use of the ePTFE adhesion barrier in gynaecological reconstructive surgery. Second-look laparoscopy to remove the membrane is not necessary.


    Acknowledgments
 
This paper is sponsored in part by W.L. Gore and Associates Inc., Flagstaff, Arizona, USA.


    Notes
 
*Paper previously presented at the XV FIGO World Congress of Gynecology and Obstetrics, Copenhagen, Denmark, August 3-8, 1997.

1 To whom correspondence should be addressed at: Department of Obstetrics and Gynecology, University of Kentucky Medical Center, 800 Rose Street, Lexington, Kentucky 40536, USA Back

§ J.Crain, Women's Specialty Center, Charlotte, NC; D.Curole, Ochsner Clinic, New Orleans, LA; G.Hill, Nashville Fertility Center, Nashville, TN; D.A.Metzger, Reproductive Medical Institute of Connecticut, Hartford, CT; A.A.Murphy, Department of Obstetrics and Gynecology, Emory University School of Medicine, Atlanta, GA; M.Perloe, Atlanta Reproductive Health Center, Atlanta, GA; H.Reich, Wyoming Valley Health Care System, Wilkes-Barre, PA; G.Rowe, Baylor College of Medicine, Houston, TX; J.S.Sanfilippo, University of Louisville School of Medicine, Louisville, KY; W.D.Schlaff, Department of Obstetrics and Gynecology, University of Colorado, Denver, CO; S.Taylor, The Fertility Institute, New Orleans, LA; and R.Wing, Women's Specialty Center, Charlotte, NC, USA. Back


    References
 Top
 Abstract
 Introduction
 Materials and methods
 Results
 Discussion
 References
 
Crain, J., Curole, D., Hill, G. et al. (1995) Laparoscopic implant of Gore-Tex surgical membrane. J. Am. Assoc. Gynecol. Laparoscopists, 2, 417–420.[ISI][Medline]

Diamond, M.P., Seprafilm Adhesion Study Group (1996) Reduction of adhesions after uterine myomectomy by Seprafilm membrane (HAL-F): a blinded, prospective, randomized, multicenter clinical study. Fertil. Steril., 66, 904–910.[ISI][Medline]

Golan, A. (1996) GnRH analogues in the treatment of uterine fibroids. Hum. Reprod., 11 (Suppl. 3), 33–41.[ISI][Medline]

Haney, A.F., Hesla, J., Hurst, B.S. et al. (1995) Expanded polytetrafluoroethylene (Gore-Tex surgical membrane) is superior to oxidized regenerated cellulose (Interceed, TC7) in preventing adhesions. Fertil. Steril., 63, 1021–1026.[ISI][Medline]

Inoue, H.K., Kobayashi, S., Ohbayashi, K. et al. (1994) Treatment and prevention of tethered and retethered spinal cord using a Gore-Tex surgical membrane. J. Neurosurg., 180, 689–693.

Jacobs, J.P., Iyer, R.S., Weston, J.S. et al. (1996) Expanded PTFE membrane to prevent cardiac injury during resternotomy for congenital heart disease. Ann. Thorac. Surg., 62, 1778–1782.[Abstract/Free Full Text]

Linsky, C.B., Diamond, M.P., Cunningham, T. et al. (1988) Effect of blood on the efficacy of barrier adhesion reduction in the rabbit uterine horn model. Infertility, 11, 273–280.

The Myomectomy Adhesion Multicenter Group (1995) An expanded polytetrafluoroethylene barrier (Gore-Tex surgical membrane) reduces post-myomectomy adhesion formation. Fertil. Steril., 63, 491–493.[ISI][Medline]

The Surgical Membrane Study Group (1992) Prophylaxis of pelvic sidewall adhesions with Gore-Tex surgical membrane: a multicenter clinical investigation. Fertil. Steril., 57, 921–923.[ISI][Medline]

Tulandi, T., Murray, C. and Guralnick, M. (1993) Adhesion formation and reproductive outcome after myomectomy and second-look laparoscopy. Obstet. Gynecol., 82, 213–215.[Abstract]

Submitted on August 7, 1998; accepted on December 21, 1998.





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