In this retrospective study, we investigated the relevant factors of pain after TVM surgery for the treatment of POP, and analysed the management and relief of pain based on our clinical experience. The incidence of pain in our study was 2.7%. Excessive intraoperative blood loss and large postoperative POP-Q values were considered as risk factors. The vagina was the most common site of pain, followed by the perineum, buttock, and groin; few patients had lower abdomen or generalised pain. In some patients, pain could be relieved by conservative therapy. Mesh removal was an effective treatment with the relief rate of 84.8%, and mesh exposure was the most common reason for the removal.
The process by which pain develops after TVM surgery is probably multifactorial, and the manifestations of pain are varied. The relationship between excessive intraoperative blood loss and postoperative pain has not been determined. A previous study shows that excessive intraoperative blood loss can increase the risk of mesh exposure 7.3-fold [23] and may lead to postoperative inflammatory reaction, which may be related to the development of pain. One out five patients with mesh exposure in our study reported pain, compared with 0-54% in the previous studies [13,18,20,24]. The exposure itself may not have been the cause of pain, while the resulting inflammatory reaction might have been relevant. It has been proposed that chronic inflammatory response caused by the exposed mesh can lead to vaginal pain [25]. Unsatisfactory postoperative anatomic outcomes may also increase the risk of pain, which may be related to the insufficient tension of the mesh. Patients with this condition may experience abdominal and perineal distension accompanied by the pain, which can also occur occasionally in untreated POP patients. In addition, although MUS is also a transvaginal implant, the concomitant MUS implantation for SUI was thought to be unrelated to the pain, in accord with previous findings [26].
Pain can sometimes resolve on its own or improve with physiotherapy, oestrogen cream, or antibiotic treatment [13,27]. Since pain usually includes hypertonia of the pelvic floor muscles, pelvic floor physiotherapy has showed a good curative effect [28]. For the mesh exposure, more aggressive management might be required when the pain appears, rather than conservative treatment such as topical oestrogen and closure of the vaginal epithelium [27]. Partial or total mesh removal is a better option for patients who have not responded to the conservative treatment, and the rate of pain relief after the mesh removal ranges from 50% to 84% in prior studies [18].
Pain can also result from mesh arms piercing the obturator space or ischiorectal fossa [29,30], which can be markedly improved after the mesh is removed. Thus, during the process of puncture for mesh implantation, we would like to emphasise that the implants must be placed in the interstitial space rather than in the tissue. In some cases, pain can be explained by bunching, folding, or contracture of the mesh [29,31]. Mesh contracture may result in a concomitant contracture of the underlying pelvic floor musculature and excessive tension on the mesh arms, causing increased pelvic floor muscle tone and tenderness [17,30]. Pain in these cases usually is unresponsive to conservative measures, but can be relieved following mesh removal. In addition, some patients had persistent pain from the moment the mesh was implanted, while no abnormality was found at the examination. In a previous study, the removal of all vaginally accessible meshes was performed in such cases [18]. Both conservative and surgical approaches in our study were used, while the improvement was unsatisfactory. The mechanism of such pain has not been clearly identified. Nevertheless, new complications may be associated with the removal of the mesh, including recurrent POP, and a concomitant prolapse repair should be performed if needed.
In this study, a small number of patients had undergone previous hysterectomy. Although several approaches including TVM for the management of POP have been reported, the best strategy for post-hysterectomy vaginal vault prolapse (VVP) remains controversial. Studies have suggested that laparoscopic sacrocolpopexy and sacrospinous fixation in the treatment of primary VVP and transvaginal bilateral sacrospinous fixation in the treatment of recurrent VVP appears to be effective and safe for the improvement of quality of life and sexual function [32]. As noted in a systematic review, TVM surgery had the highest reoperation rates (including complications and recurrence) in the treatment of VVP [33]. Therefore, we should be more careful in evaluating and selecting the appropriate approach before the TVM is intended for the reconstruction of VVP.
Health-related quality of life (HR-QoL) is widely recognised as an important outcome measure following urogynaecological surgery [34]. Taking into account the significant impact of POP on physical and mental health [35], in addition to the surgical effect, that is, anatomical reduction, surgeons should focus on the assessment of postoperative function recovery and improvement of quality of life of the patients. Therefore, multidisciplinary approach in the treatment of women with POP is very important. Although studies have shown that general HR-QoL improved significantly (mainly shown as improvement of sexual activity, mobility, excretion, depression, etc.) after apical POP reconstructive surgery [36], the use of TVM can still lead to some serious complications, such as pain, sexual dysfunction, and mesh exposure [11]. Therefore, the application of TVM should have strict indications, and is usually recommended for patients ≥50 years old or with low sexual activity, severe pelvic floor structural damage, or recurrence [21,35]. Surgeons should weigh the risks and benefits on an individual level based on the patient characteristics when opting for mesh kits for surgical repair, to achieve better treatment outcomes in patients with POP.
This study had the following limitations: Firstly, pain was not directly measured with validated instruments, and the metric used for pain relief was based on subjective phrases in medical records at times. Secondly, since the mesh we used was mainly Prolift™, the factors of mesh itself (size, shape and material) are not included in the study. Then, since the pain may occur years after surgery, longer-term follow-up might be required. Finally, the cases in this study came from specific regions, and it is unclear whether the conclusions can apply to patients in other parts of the world. This study had several limitations. First, pain was not directly measured with validated instruments, and the metric used for analysis of pain relief was based on subjective phrases in medical records at times. Second, since the pain may occur years after the surgery, longer-term follow-up might be required. Third, the cases in this study were collected from specific geographical regions, and it is unclear whether the conclusions can apply to patients in other parts of the world.
Despite these limitations, the evidence of our study is strengthened by the relatively large number of patients and detailed data available from surgical and medical records. Moreover, this study investigated the relevant factors of postoperative pain, one of the inconvenient complications after the TVM surgery, the observations of which are relatively new to the available literature. The clinical practice shown in this study may provide important information about the strategy of the pain management following TVM surgery. In the future, we will carry out more in-depth studies on the mesh complications to provide more important reference for the postoperative management of TVM.