Polypropylene anterior-apical single-incision UPHOLD-LITE mesh surgery in women with severe pelvic organ prolapse: Outcome at 53 months follow up.

BACKGROUND AND PURPOSE: We present this current study to complement with mesh inlays plausible benefits (UPHOLD-LITE System) on available long-term study amidst FDA's concern on mesh complications. This study aims to assess the medium-term outcomes of UPHOLD-LITE system for treatment of advanced pelvic organ prolapse (POP) and its complications, and lower urinary tract symptoms. METHODS: This is a retrospective case series of 53 months follow-up of 123 consecutive patients who underwent UPHOLD-LITE system. Objective outcome measures the anatomical correction of prolapse with POP-Q ≤ Stage 1. Subjective outcome was patient's feedback to questions 2 and 3 of POPDI-6. Secondary outcome measures the quality of life, presence of lower urinary tract symptoms and complications. Quality of life is assessed by validated questionnaires on Urogenital Distress Inventory 6 (UDI-6), Incontinence Impact Questionnaire 7 (IIQ-7), Pelvic Organ Prolapse Distress Inventory 6 (POPDI-6), and Pelvic Organ Prolapse/Urinary Incontinence Sexual Function Questionnaire 12 (PISQ-12) at 1 and 3 years post-operatively. RESULTS: Objective outcome at 1 and 3 years was at 96.7 % and 95.4 % respectively. The subjective cure was 95.1 % and 91.6 %. Five-year cumulative cure rate maintained at 87.2 %. Secondary outcomes observed improvement on UDI-6, IIQ-7, POPDI-6 and PISQ-12 postoperatively. Bladder outlet obstruction improved while de novo urodynamic stress incontinence (USI) increased slightly post surgically. Mesh erosion rate was 0.8 %. CONCLUSION: The UPHOLD-LITE system demonstrated good medium term anatomical correction of apical and anterior prolapse, with good subjective cure and improved quality of life. Whilst complication rate was low, slight increase in de novo USI was observed.

Immunochemical analysis on polypropylene mesh: does mesh size make a difference?

INTRODUCTION AND HYPOTHESIS: The aim of the study is to demonstrate the impact of the size of implanted mesh in relation to its immunohistochemical reaction implanted into animal models. METHODS: An experimental study utilizing 54 female Sprague Dawley (SD) rats was divided into five groups: control, sham, and study groups (mesh-small [M-S], mesh-medium [M-M], mesh-large [M-L]). The M-S group used a mesh size of 0.2 × 0.2 cm, the M-M group a mesh size of 0.5 × 0.5 cm, and the M-L a mesh size of 0.7 × 1.0 cm. The sham group underwent vaginal dissection with no mesh implantation. The rats were sacrificed using isoflurane overdose on days 7 and 30. The mesh with the surrounding vaginal and bladder wall tissues were removed and processed for histochemical and western blot analysis. RESULTS: There is a significant increase in IL-1 and TNF-α immunoreactivity in the M-M and M-L groups on day 7 when compared with the sham group with p values of 0.001 and < 0.001 respectively. M-L showed significantly higher immunoreactivity to TNF-α persisting until day 30. All study groups presented a significantly higher immunoreactivity to MMP-2 and NGF on day 7. However, reactivity to NGF does not persist to day 30 in all groups. Immunoreactivity to CD 31 on days 7 and 30 appears significantly greater in the M-M and M-L groups, with the reaction in the M-L group continuing until day 30. CONCLUSION: Mesh size is directly proportional to the inflammatory reaction in the host tissue. The prolonged inflammatory process leads to delayed tissue remodeling and angiogenesis, which could delay mesh-tissue integration.

Outcomes and failure risks in mid-urethral sling insertion in elderly and old age with urodynamic stress incontinence.

INTRODUCTION AND HYPOTHESIS: To study the surgical outcomes and risk factors for failure of three types of mid urethral slings(MUS) surgeries in elderly and old age women with urodynamic stress incontinence(USI). METHODS: Three different types of MUS surgeries [single incision sling(SIS), trans-obturator tape(TOT), retro-public mid-urethral sling-tension-free vagina tape (TVT)]were performed among three age groups of women (young <64 yr, elderly 65-74 yr and old >75 yr) with USI. They were followed up for 1 year. RESULTS: Complete postoperative data was available for 688 women. After 1 year, overall objective cure rate was 88.2% and subjective cure rate was 85.9%. Among the young, elderly, and old age women objective cure rates were 91.0%, 80.6%, 66.7% and subjective cure rates were 89.2%, 77.6%, 58.3% respectively. Urodynamic parameters demonstrated flow rate, higher post-void bladder residual, smaller cystometric capacity, and lower maximum urethral closure pressure were significantly lower among old and elderly group. Subjectively, urinary distress inventory-6 (UDI-6) and incontinence impact questionnaire-7(IIQ-7) improved significantly in all groups with significant changes from baseline only in older women. Intrinsic sphincter deficiency(ISD) was found to be significantly associated with failure in older women. Other preoperative comorbidities were equally distributed among all the three age groups. The operative time, perioperative complications, and length of hospital stay showed no difference between the study groups. CONCLUSIONS: MUS surgery is safe for the young and aging patients with USI and demostrated significant improvement in its outcomes, but objective and subjective cure rates decreases with age. ISD was also found to be significantly associated with failure.

Outcomes of urodynamic mixed urinary incontinence and urodynamic stress incontinence with urgency after mid-urethral sling surgery.

INTRODUCTION AND HYPOTHESIS: Mixed urinary incontinence (MUI) is defined as symptomatic complaint of involuntary leakage associated with urgency and also with exertion, effort, sneezing or coughing. The paucity of research, especially on the surgical management of MUI, limits its best management. METHODS: This is a retrospective study to determine the outcomes of mixed urinary incontinence after mid-urethral sling surgery with two groups, urodynamic stress incontinence (USI) with urgency and urodynamic mixed urinary incontinence (MUI-UD; USI and detrusor overactivity [DO]). RESULTS: Ninety women (USI + urgency group) with preoperative USI and urgency and no demonstrable DO/DOI attained an objective cure of 82.2%, whereas the remaining 67 (MUI-UD group) women with both USI and DO/DOI were reported to have an objective cure of only 55.2%. Subjective cures were 81.1% and 53.7% respectively. The type of incontinence surgery does not affect postoperative outcomes in either of the groups. Demographic factors identified to have a significant negative effect on cure rates were postmenopausal status (p = 0.005), prior hysterectomy (p = 0.028), pre-operative smaller blafdder capacity (p = 0.001), and a larger volume of pre-operative pad test (p = 0.028). A lower mid-urethral closure pressure (MUCP) was significant with post-operative failure of treatment with MUI-UD group (68.8 ± 36.2 cmH2O vs 51.9 ± 24.7 cmH2O; p = 0.033). CONCLUSIONS: Although there is evidence for a good cure of the stress component of MUI, urodynamic investigation with its findings prior to management of MUI could have greater implications for selective patient centered counseling. Presence of DO or DOI on urodynamics resulted in poorer objective and subjective outcomes.

Prophylactic midurethral sling insertion during transvaginal pelvic reconstructive surgery for advanced prolapse patients with high-risk predictors of postoperative de novo stress urinary incontinence.

INTRODUCTION AND HYPOTHESIS: Our aim was to evaluate the clinical outcome of continent women with high-risk predictors for de novo stress urinary incontinence (SUI) offered prophylactic midurethral sling (MUS) insertion during vaginal pelvic reconstructive surgery (PRS) for advanced pelvic organ prolapse (POP). MATERIALS AND METHODS: This was a prospective cohort study in patients with POP stage ≥ 3 and maximum urethral closure pressure (MUCP) <60 cmH2O and functional urethral length (FUL) <2 cm. Patients were divided into PRS and PRS + MUS groups. Surgery commenced with vaginal hysterectomy, application of Uphold® and insertion of MUS to the PRS + MUS group. Main outcome measures were incidence of de novo urodynamic stress incontinence (USI), lower urinary tract symptoms (LUTS), quality of life (QoL), and topographic and anatomical relationship of implanted mesh. RESULTS: Based on sample size calculation, 40 patients were recruited-20 in each group. Rate of de novo USI in PRS + MUS was 5% objectively and 10% subjectively, while in the PRS it was 50% objectively and 60% subjectively. No significant difference was noted in patient demographics. Intraoperative blood loss was greater for PRS + MUS but was not statistically significant. No organ injuries, mesh exposure, or infections occurred. Postoperatively, MUCP significantly increased from 43.3 ± 8.9 to 58.5 ± 19.2 cmH2O and FUL from 17.2 ± 1.9 to 20.3 ± 3.1 mm in the PRS + MUS group. Residual urine significantly decreased. No patient had bladder outlet obstruction (BOO). Sonographic assessment showed no difference in mesh mobility with urethral kinking observed in 11 (55%) patients with MUS. CONCLUSION: Based on a validated small sample, prophylactic MUS for continent women at high risk for postoperative USI with advanced POP lowers its incidence to 5%. Continence is achieved in 95%. Concern for complications, LUTS, and QoL did not significantly differ.

Clinical outcomes on tension-releasing suture appendage on single-incision sling devices for postoperative voiding dysfunction involving undue tape tension.

INTRODUCTION AND HYPOTHESIS: To determine the clinical outcomes of adding a tension-releasing suture (TRS) appendage for manipulation of over-tensioned single-incision slings (SIS) as a means to relieve postoperative voiding dysfunction. METHODS: A retrospective observational study conducted from January 2010 to July 2017. The records of patients with urodynamic stress incontinence (USI) without needing concurrent procedures who underwent anti-incontinence surgery using MiniArc, Solyx, and Ajust with voiding dysfunction were collated and analyzed. The primary outcome measure was the recovery of normal post-void residual urine (PVR) after TRS manipulation. The secondary outcome measures were the pain intensity noted during manipulation (quantified by visual analog scale) and the continence rate [assessed by (1) objective cure: 1-h pad test weight < 2 g and absence of USI; (2) subjective cure index score ≤ 1 on question 3 of the UDI-6: "Urine leakage related to physical activity, coughing, or sneezing?"]. RESULTS: There were 73 patients with high post-void residual (PVR) urine. The 42 (9.5%) patients with over-tensioned slings were managed with TRS manipulation while the 31 patients (7%) with high PVR and no sling over-tension were managed with intermittent catheterization. All patients in both groups regained normal PVR. The TRS-manipulated group demonstrated an objective cure rate of 92.9% (39/42) and subjective cure rate of 91% (38/42). Pain experienced during TRS manipulation was significantly higher with the Ajust system (p = 0.018). Three patients had persistence of USI, two with MiniArc and one with Solyx. CONCLUSIONS: The TRS manipulation is a well-tolerated procedure that can effectively relieve voiding dysfunction for over-tensioned SIS without affecting continence cure rates.

Evaluation of Clinical Outcome and Risk Factors for Failure of Single-incision Midurethral Short Tape Procedure (Solyx Tape) for Stress Urinary Incontinence.

STUDY OBJECTIVE: To evaluate the clinical outcome and identify risk factors for failure of the Solyx (Boston Scientific Corporation, Marlborough, MA) single-incision sling (SIS) in the treatment of urodynamic stress incontinence (USI). DESIGN: A retrospective observational study (Canadian Task Force classification II-2). SETTING: A tertiary referral center. PATIENTS: Patients diagnosed with USI without needing concurrent procedures that underwent continence surgery using the Solyx SIS from February 2015 to May 2017. INTERVENTIONS: Anti-incontinence surgery. MEASUREMENTS AND MAIN RESULTS: The primary outcome of this study was the rate of objective cure defined as the absence of demonstrable leakage of urine on the cough stress test and a 1-hour pad test weight of less than 2g. The secondary outcome was the rate of subjective cure defined as a negative response to Urinary Distress Inventory question 3 (no leakage on coughing, sneezing, or laughing) and the identification of the different risk factors of cure failure. A total of 113 patients were evaluated in the study. Postoperative USI and the 1-hour pad test significantly improved from 24.2 ± 26.9 gm (range, 19.1-29.3) to 2.5 ± 8.7 gm (range, 0.9-4.2); p <0.001 through 1 year. Data analysis showed an objective cure rate of 90% (102/113) and a subjective cure rate of 86% (97/113). USI recurred in 11 patients with no repeat surgery done becausesymptoms were tolerable to the patients. No patient had bladder outlet obstruction. Peak flow rates 23.7 ± 9.1 ml/s (20.0-27.4) and residual urine volume 38.5 ± 25.8 ml (29.8-47.2) were within normal limits with no significant changes. Previous anti-incontinent surgery, previous prolapsed surgery, intrinsic sphincter deficiency, maximum urethral closure pressure <40cm H2O, and neurogenic disease were significant risk factors for sling failure. Subjective assessment on the quality of life significantly improved (p <0.001). CONCLUSION: The Solyx SIS is an effective and safe treatment option for women with USI, showing high objective and subjective cure rates with a low incidence of complications 1 year after treatment. The identified independent risk factors forfailure are related to poor urethral function and previous pelvic reconstructive surgery.

Clinical outcomes of detrusor underactivity in female with advanced pelvic organ prolapse following vaginal pelvic reconstructive surgery.

AIM: To determine the impact of vaginal pelvic reconstructive surgery (PRS) on detrusor underactivity (DU) patients having advanced pelvic organ prolapse (POP). METHODS: A retrospective study of patients who underwent PRS for advanced POP (POP-Q ≥ 3) with DU. Data regarding preoperative evaluation, surgical procedure, and post-operative management were collated. Patients were considered to have DU when detrusor pressure at maximum flow (Pdet Qmax ) was ≤10 cmH2 0 and peak flow rate (Qmax ) of ≤12 mL/s. Post-operative values more than the cut-off were considered objectively cured. Subjective cure was defined as having a negative response to UDI-6 Question 5, "Do you experience difficulty emptying your bladder?" RESULTS: A total of 49 patients were evaluated. Majority of the population were post-menopausal and multiparous. Preoperatively, 38 patients (75%) had stage III prolapse and 13 patients (26%) had stage IV. Subjective cure rate of DU was 76% (37/49) and objective cure rate was 47% (23/49). Post-operative DU (P < 0.001) significantly improved together with patients having normal urodynamic diagnosis (P < 0.001). Voiding function showed significant increase in Qmax (P < 0.001) and Pdet Qmax (P < 0.001) while PVR (P < 0.001) and cystometric capacity (P < 0.001) significantly decreased. These findings were observed in 89% (43/49) of patients with post-void residual urine (PVR) of <200 mL, 63% (31/49) with Qmax > 12 mL/s, and 57% (28/49) with Pdet Qmax >10 cmH2 0. CONCLUSION: Reversal of short-term or long-term obstruction through vaginal pelvic reconstructive surgery enables bladders to regain detrusor muscle function. Although objective cure of DU was at 47%, detrusor function recovered in 57% of patients provided that mechanical obstruction was the cause.

Sacrospinous ligament fixation for hysteropexy: does concomitant anterior and posterior fixation improve surgical outcome?

INTRODUCTION AND HYPOTHESIS: Uterine preservation in uterine prolapse is an option for young patients. We hypothesized that sacrospinous hysteropexy (SSH) with anchorage to both the anterior and posterior cervix (SSH-ap) would have a better outcome than SSH with anchorage to the posterior cervix only (SSH-p). METHODS: This was a retrospective study including 75 patients who underwent SSH at Chang Gung Memorial Hospital between March 2008 and August 2013. Five were excluded due to incomplete data. Of the remaining 70 patients, 35 underwent SSH-p between March 2008 and June 2011, and 35 underwent SSH-ap between June 2010 and August 2013. The primary outcome was the objective anatomical result, and a successful outcome was considered anatomical correction (POP-Q stage 1 or less) of anterior and apical prolapse. Subjective outcome was evaluated using the POPDI-6 questionnaire, and a patient response of "No or mild abdominal organ falling out sensation" together with "No or mild heaviness" was considered to indicate a successful outcome. Anterior fornix and cervical diameter measurements were included. The secondary outcome was quality of life according to the UDI-6, IIQ-7, POPDI-6, and PISQ-12 questionnaires. The 3-year outcome was used for comparison. RESULTS: The subjective overall cure rates were significantly different between the SSH-p and SSH-ap groups (74.3% and 94.3%, respectively; p = 0.023). However, the objective overall cure rates were not significantly different (74.3% and 82.9%, respectively). CONCLUSION: Anchorage of the anterior cervix and vaginal wall together with the usual posterior anchorage yield better subjective outcomes and apical suspension at 3 years after surgery than anchorage of the posterior cervix and vaginal wall only. The cervix position affected the subjective outcome. Concurrent trachelectomy did not affect the outcome.

Five-Year Outcome of MiniArc Single-Incision Sling Used in the Treatment of Primary Urodynamic Stress Incontinence.

STUDY OBJECTIVE: To evaluate the effectiveness and safety of the MiniArc single-incision sling in the treatment of urodynamic stress incontinence (USI) through 5 years. DESIGN: Retrospective observational study (Canadian Task Force classification II-2). SETTING: Tertiary referral center. PATIENTS: Eighty-five patients with USI without needing concurrent procedures who underwent anti-incontinence surgery using the MiniArc SIMS from February 2010 to December 2011. INTERVENTIONS: Anti-incontinence surgery. MEASUREMENTS AND MAIN RESULTS: Objective cure was defined as no demonstrable leakage of urine on the cough stress test and 1-hour pad test weight <2 g. Subjective cure was based on negative response to Urinary Distress Inventory question 3, no leakage on coughing, sneezing, or laughing. Most patients were postmenopausal, overweight, and multiparous. Postoperative USI significantly improved (p < .001) through 3 years, and the 1-hour pad test showed significant improvement through 5 years (p < .001). Although 13 patients had recurrence of USI, no repeat surgery was done. The cumulative cure rates may show a declining trend of cure, yet subjective cure was 80.0% and objective cure 84.7%, with age as a significant risk factor for sling failure. CONCLUSION: MiniArc maintains its effectiveness and safety in treatment of USI through 5 years with high objective and subjective cure rates and low incidence of complications.

Dissecting of the paravesical space associated with lower urinary tract dysfunction - a rat model.

To determine the association of opening the paravesical space in relation to its occurrence of de novo SUI in an animal model. Thirty five female Sprague Dawley rats were divided into 5 groups of 7 rats each: Control group, Sham groups(F, H), and Study groups(MF, MH). Groups labeled with "F" had the paravesical space opened, "H" had tissue dissection with no opening of the space, and "M" had mesh implanted inside the vaginal wall. Urodynamic studies, immunohistochemical analysis, and western blot were done at day 40. The mean weight and age of 35 rats were 302.1 ± 25.1 grams and 12.8 ± 1.2 weeks old. No significant differences were noted among the control, Sham F, Sham H, Study MF, and Study MH on the voiding pressure and voided volume. The Sham F and Study MF (opened paravesical space) groups had significantly lower values on leak point pressures (LPP) (p = 0.026; p < 0.001) and shorter voiding intervals (p = 0.032; p = 0.005) when compared to other groups. Immunohistochemical analysis showed IL-1 and TNF-α to be intensely increased for the Study MF group (p = 0.003; p = <0.001). MMP-2 and CD 31 markers were also significantly higher in the Study MH and MF group. NGF expression was significantly increased in the Study MF and Sham F groups. Thus, opening of the paravesical space causes an increased inflammatory reaction, which leads to tissue destruction and lower urinary tract dysfunction, exemplified in the study with low leak point pressure and shortened voiding intervals.

Urodynamics mixed type urinary incontinence with advanced pelvic organ prolapse, management and outcomes.

Patients with pelvic organ prolapse (POP) often have accompanying lower urinary tract symptoms. Symptoms such as stress urinary incontinence(SUI-UD) and detrusor overactivty(DO) would co-exist in a number of patients. Management entails relieving the obstructive element. To determine the clinical outcome of patients with urodynamics mixed type urinary incontinence(MUI-U) after vaginal pelvic reconstructive surgery(PRS), a retrospective study was conducted. MUI-U was defined as having urodynamic findings of both of DO/DOI (derusor overactivity incontinence) and SUI-UD. Main outcome measures: Objective cure- absence of involuntary detrusor contraction on filling cystometry and no demonstrable leakage of urine during increased abdominal pressure; Subjective cure- assessment index score of <1 on UDI-6 question #2 and #3. Of the 82 patients evaluated, 14 underwent vaginal PRS with concomitant mid-urethral sling(MUS) insertion while 68 had vaginal PRS alone. Pre-operatively, 49(60%) patients had stage III and 33(40%) had stage IV prolapse. Post-operatively, 1-year data shows an objective cure of 56% (46/82) and subjective cure of 54% (44/82). MUI-U was significantly improved. Improvement of SUIUD and results of the 1-hour pad test were more pronounced in patients with concomitant MUS insertion. Ergo, vaginal PRS cures symptoms of MUI-U in >50% of patients and concomitant MUS can be offered to SUI predominant MUI.

Clinical relevance and treatment outcomes of vesicovaginal fistula (VVF) after obstetric and gynecologic surgery.

OBJECTIVE: Vesicovaginal fistulas (VVF) are consequences from obstetric and gynecologic surgery. Treatment approach from either abdominal or vaginal route have its own pros and cons. The study aims to present the anatomical, clinical and lower urinary tract symptom outcomes of women with VVF. MATERIALS AND METHODS: A retrospective case series conducted patients with VVF. Data regarding pre-operative evaluation, surgical treatment, and post-operative follow-ups were collected. Surgical approach depended on the cause, type, number, size, location, and time of onset of the fistula. Post-operatively, foley catheter was maintained for at least 1 week with cystoscopy performed prior to removal. Follow-up evaluation included cystoscopy, bladder diary, UDI-6 and IIQ-7 questionnaires and multi-channel urodynamic study. RESULTS: Of the 15 patients that were evaluated, 1 had spontaneous closure, 8 were repaired vaginally and 6 abdominally. Patients repaired vaginally were significantly noted to have a mean age of 50.3 ± 7.1 years with VVFs located adjacent the supra-trigone area having a mean distance of 1.7 ± 0.5 cm from the ureteric orifice. Its operative time and hospital stay were significantly shorter. In contrast, abdominally repaired patients had mean age of 38.0 ± 8.2 years and VVFs with mean distance of 0.4 ± 0.4 cm from the ureteric orifice. Post-operatively, 2 cases (14.2%, 2/14) of VVF recurrence and de novo urodynamic stress incontinence (USI) (25%, 2/8) were noted after vaginal repair and 3 cases (50%, 3/6) of concurrent ureteric injury and overactive bladder after abdominal repair. CONCLUSION: Treatment outcomes for vaginal and abdominal repair yielded good results. Though the vaginal route had higher incidence of recurrence and de novo USI, its less invasiveness, faster recovery period, and no association with post-op overactive bladder made it more preferable than the abdominal approach.

Ultrasonography and clinical outcomes following anti-incontinence procedures (Monarc vs MiniArc): A 3-year post-operative review.

OBJECTIVE: To compare the ultrasonographic positional changes of mid-urethral sling(MUS) tape in relation to symphysis pubis, and the different clinical outcomes among women who underwent MUS insertion with MiniArcTM or MonarcTM for the treatment of stress urinary incontinence 3 years after. MATERIALS AND METHODS: A retrospective follow-up study on patients with clinically confirmed stress urodynamic incontinence and urodynamic stress incontinence who had undergone MiniArc or Monarc surgery. Data regarding preoperative evaluation, intraoperative complications and post-operative follow-ups were collated. Main outcome is to determine the change in position of the sling through measurement of the x- and y-axis at rest and during Valsalva maneuver using the 3D introital ultrasound. RESULTS: A total of 138 patients were evaluated, 82 belonged to Monarc and 56 to MiniArc. At 3years, objective and subjective cure rates for MiniArc and Monarc were comparable (88%, 91%; p>0.05; 83%, 89%, p>0.05 respectively). Ultrasonographic changes between MiniArc and Monarc from 6 months to 3 years, showed MiniArc to exhibit significant movement in both x- [3.0 ±0.4 mm vs. 2.2 ±0.3 mm (p = 0.02) at rest; 2.6 ±0.3 mm vs. 1.6 ±0.3 mm (p<0.001) during valsalva] and y-axis [3.5 ±0.5 mm vs. 2.0 ±0.3 mm (p<0.001) at rest; 3.3 ±0.5 mm vs. 2.9 ±0.3 mm (p = 0.037) during Valsalva]. The mobility of MiniArc was significantly more than Monarc from rest to Valsalva (1.1 ±0.4 mm vs. 0.3 ±0.3 mm, p = 0.001). Tightness of the sling assessed from the major and minor axis of the urethral core had no significant difference in both groups at rest and during Valsalva. Urethral kinking percentage and the location of the sling did not yield statistical difference. CONCLUSION: Maintenance of continence rates of mid-urethral slings depends on the compressive effect of the sling on the urethra, urethral kinking, and sling fixation. From 6months to 3 years, MiniArc changed its position in both x- and y-axis over time, which the authors attribute to loosening of the anchoring mechanism since no clinical relevance could be sought.