Surgical Adhesion Prevention

A hydrogel that is sprayed directly on tissues during pelvic surgery may prevent adhesions from forming between tissue surfaces. Adhesions are abnormal attachments between tissues or organs and are a major cause of chronic pelvic pain, infertility, and intestinal obstruction.[1,2]

A Significant Problem

Abdominal adhesions are estimated to occur in up to 90% of women following pelvic surgery or appendectomy.[3] To relieve pain or free an obstruction, additional adhesiolysis surgery may be required to separate or remove the adhesions.

In the US, the annual cost for adhesiolysis is estimated to be US$1.3 billion.[3]

Hydrogel Anti-adhesion Products

SprayGel® Adhesion Barrier (Confluent Surgical, Waltham, MA) and Adhibit™ adhesion prevention gel (Angiotech Pharmaceuticals Inc., Vancouver, BC) are two synthetic hydrogel products that are being investigated for use in laparoscopic (“keyhole”) or open pelvic surgery procedures.

The products are sprayed onto the surgical site as two separate streams of polyethylene glycol-based precursor liquids, which rapidly cross-link on the target tissue to form a flexible, adherent, bioabsorbable gel barrier.[1]

The Evidence

Adhibit

A randomized, controlled, single-blind study of 71 women who had surgery to remove uterine fibroids (myomectomy) reported that 48 women who received Adhibit (0.8±2.0) had a reduction in adhesions compared with 23 women in a control group who did not receive the gel (2.6±2.2, p=0.01).[4] Adhesions were measured eight to 10 weeks after the surgery, using the modified American Fertility Society score.

SprayGel

A randomized study of 66 women who underwent myomectomy with or without SprayGel reported that seven of 22 patients (31.8%) in the SprayGel group and two of 18 (11.1%) patients in the control group were free of adhesions three to 16 weeks after the surgery.[1]

Regulatory Status

Neither Adhibit nor SprayGel are currently licensed in Canada or the US. Adhibit was approved in Europe in August 2002 to prevent or reduce the incidence, severity, and extent of post-surgical adhesions during cardiac surgery.[5] SprayGel received European marketing approval in November 2001 for use in laparoscopic or open surgery.[2] Adhibit is chemically identical to Angiotech’s CoSeal® Surgical Compound, which was licensed in Canada in 2002 as a vascular sealant.

Cost

According to European distributor Q Medical International, SprayGel costs €275 (approximately C$385) for a 2x5 mL syringe kit and a laparoscopic applicator. For extensive pelvic surgery cases, two to five kits may be required to cover the complete area.[2] Adhibit is supplied as a 2x4 mL kit; pricing information is unavailable.

Future Products

In the future, solid hydrogel barriers may be loaded with drugs such as paclitaxel, for improved barrier performance.[5]

References

[1] Mettler L, et al. Fertil Steril 2004;82(2):398-404.

[2] Trew G. Reviews in Gynaecological and Perinatal Practice 2006;6:47-56.

[3] Ray NF, et al. J Am Coll Surg 1998;186(1):1-9.

[4] Angiotech presents positive Adhibit^TM data at the 19th annual European Congress of Obstetrics and Gynecology: surgical adhesion scores were threefold less in patients treated with Adhibit^TM. Vancouver: Angiotech Pharmaceuticals; 2006. Available: http://www.bcbiotech.ca/News/Member_Press_Releases/pr04070602.asp

[5] Technology for surgical adhesions. Vancouver: Angiotech Pharmaceuticals; 2006. Available: http://www.angiotech.com/?seek=30