Study population and data collection
From February to April 2018, eight unselected consecutive patients with pelvic organ prolapse were recruited for laparoscopic or RVMR with a synthetic MR–visible polyvinylidene fluoride (PVDF) mesh in Oulu University Hospital, Finland. Written informed consent was obtained from all patients. All data about patient characteristics and post-operative recovery were collected prospectively. The study was approved by the local Ethics Committee.
Surgical technique
The surgical procedures were primarily carried out as described by D’Hoore and Penninckx [
2] with minor modifications. The da Vinci Surgical System (Intuitive Surgical Inc., Sunnyvale, CA, USA) with five trocar placements and side docking was used to perform RVMR. The mesh was positioned as far distally as possible and sutured to the levator muscles and on the anterior rectal wall with multiple interrupted seromuscular non-absorbable sutures (2-0 Ethibond, Ethicon Endosurgery). In laparoscopic procedures, only four to five sutures were used to fix the mesh on the proximal rectal wall, and the distal part of the mesh was fixed with glue. For the sacral promontory fixation, spiral attachments (Pro-Tack TM Fixation Device, Medtronic) were used. The peritoneum was closed over the mesh with continuous suture with absorbable V-Loc™ 90 (Medtronic). Peri-operative care was conducted according to the enhanced recovery after surgery protocol.
MR–visible polyvinylidene fluoride (PVDF) 4 × 23 cm meshes (Dynamesh® IPOM, FEG Textiltechnik, Aachen, Germany) containing paramagnetic iron oxide microparticles (Fe3O4 with iron load of 10 mg/g polymer) were used. This macroporous (> 1 mm) mesh consists of 88% visceral-sided PDVF monofilament and 12% parietal-sided polypropylene monofilament.
Magnetic resonance imaging
Magnetic resonance imaging (MRI) was performed by a 3 T magnet (Siemens, Vida, Erlangen, Germany). The patients were asked to empty the bladder before imaging. No other patient preparation was used. Patients were lying supine in the magnet. A body matrix surface coil was used in addition to the posterior spine coil.
T2-weighted sagittal, coronal, and transverse images were obtained (TR 3720–6100, TE 81–90, sagittal and coronal FOV 230, transverse FOV 200, 3 mm slice, 0.6 mm gap, sagittal and coronal matrix 256 × 320, transverse matrix 544 × 640). Breath-hold transverse T1-weighted vibe Dixon (TR 4, TE 1.3 and 2.5, FOV 309 × 380, 3 mm slice, 195 × 320 matrix) and T1-weighted (TR 129, TE 2.5, FOV 333 × 380, 3 mm slice, 210 × 320 matrix) flash images were also obtained. Total time of the examination was 30–35 min.
The visibility of the mesh in each sequence was assessed subjectively. Scores from 1 to 4 were used. Score 1 was given to image series if the mesh was visible in all slices. In score 2, 3, and 4, the visibility was ≥ 3/4, ≥ 1/2 or < 1/2 of the slices.
The position of the lower insertion point according to anorectal junction was assessed, as well as the insertion point to the levator muscle on each side. The length of insertion to the anterior rectal wall was measured. The width of the mesh was measured at the lower insertion point, at the highest insertion point in the rectum, and at the higher insertion point in the promontorium. Also, the narrowest part of the mesh was measured, as well as its distance from the highest rectal insertion point.