Objective
Mesh implants are widely used in surgery for female pelvic organ prolapse. Mesh shrinkage is thought to be common and caused by immunological processes. In this longitudinal study, we examined mesh dimensions at 2 time points after implantation.
Study Design
We analyzed translabial 4-dimensional ultrasound (US) volume datasets of women seen 3-52 months after anterior compartment mesh. Datasets of first and last postoperative appointments were analyzed, with the operator blinded against all other data.
Results
Forty women were assessed at least twice, comprising 59.6 woman-years. Thirty-seven of 40 (93%) were satisfied at their last appointment. Eighteen of 40 considered themselves cured, and 18 of 40 felt improved. Objective recurrence (cystocele stage 2 or greater) was seen in 16 of 40. Midsagittal mesh length increased significantly (35.8 vs 32.7; P = .006), and coronal mesh diameters increased nonsignificantly (37.4 vs 36.6 mm; P = .44).
Conclusion
Over an observation period of almost 60 woman-years, we found no evidence of mesh contraction.
Mesh implants are widely used in surgery for female pelvic organ prolapse. Complications such as erosion and pain syndromes are not uncommon, but so is recurrence of prolapse, which provided the motivation for the development of mesh kits in the first instance. Up to one third of all prolapse procedures are performed for recurrence. Anterior compartment recurrence seems to be a particular problem, and this seems associated with previous recurrence, prolapse severity and with major trauma to the levator ani muscle (avulsion).
Mesh implantation may be the only way to achieve acceptable success rates in women at high risk of recurrence, although the effect of commercially available mesh kits on prolapse recurrence is unknown because of a lack of randomized controlled intervention trials. Although there have been calls for such a trial in the United Kingdom, such a trial is unlikely to be useful clinically unless major predictors of failure are accounted for as confounders.
It has recently been claimed that mesh contraction is a common cause of mesh-related pain, erosion, and recurrence, which is held by some authors to be due to immunological processes rather than surgical methods or technique. Some authors have claimed that wide-weave polypropylene mesh may contract 10% per year, reaching a 85% reduction in volume by year 8. If this was true, one would have to seriously question the basis for mesh use in prolapse surgery.
It is claimed that new meshes are needed to reduce contraction and the complications supposedly associated with mesh shrinkage, which would have substantial consequences regarding research and development. In this longitudinal study, we attempted to determine whether mesh contraction occurs after Perigee (American Medical Systems, Minnetonka, MN) transobturator mesh placement. This implant was the first transobturator mesh used in prolapse surgery, invented in 2004 by Ajay Rane and Malcolm Frazer, and it has become the template for all other anterior compartment meshes used since.
Materials and Methods
As part of an ongoing audit of prolapse surgery, we analyzed ultrasound volume datasets obtained from women attending follow-up appointments 3 months to 5 years after Perigee mesh placement at our hospital. Perigee mesh augmentation of anterior colporrhaphy had been performed in standardized fashion according to the manufacturer’s instruction, with the difference that we remove the tail of the mesh entirely before implantation. This leaves an almost square piece of mesh between the anchoring arms, of approximately 5.0 × 3.7 cm 2 in area. In all cases the mesh was anchored to underlying tissues cranially and caudally, using between 1 and 3 sutures to fix the mesh margin to the bladder base.
Postoperative assessments included a local, nonvalidated questionnaire that comprised questions regarding patient satisfaction (yes/no/not sure) and subjective perception of cure (cured/improved/ same/worse). The clinical examination was performed in the supine position after bladder emptying, using the prolapse quantification system of the International Continence Society (ICS) Pelvic Organ Prolapse Quantification System (POP-Q), and objective recurrence was defined as a cystocele stage 2 according to this system. Patients were examined by translabial ultrasound as previously described, at rest, on maximal Valsalva and on pelvic floor muscle contraction, supine and after bladder emptying. Great care was taken to avoid levator coactivation.
The datasets of the first (minimum 3 months) and last postoperative appointments (maximum 4.6 years) were selected and analyzed using the postprocessing software 4D View (GE Medical; Kretz Ultrasound, Zipf, Austria), with the operator blinded against all clinical data and against the order in which the volumes had been obtained. For volumes obtained during the first and last 12 months of the observation period, the operator (M.E.) was also blinded against all calendar dates contained in the volume datasets, making it impossible to deduce the order of assessments.
Measurements of mesh location and maximum descent were taken relative to the symphysis pubis, similar to the methodology used for determining pelvic organ descent. For this purpose a line is placed horizontally through the inferior margin of the symphysis pubis, and the location of the most caudal mesh margin is determined relative to this line. Mesh dimensions were determined in the midsagittal and coronal plane, as illustrated in the Figure . Occasionally in women with a large recurrent rectocele, volumes obtained on maximal Valsalva did not allow full visualisation of superior aspects of the mesh. In such cases we used volumes obtained on submaximal Valsalva.
