Twin-twin transfusion syndrome: the good news is; there is still room for improvement …

Development and validation of a flexible fetoscope for fetoscopic laser coagulation

PURPOSE

Fetoscopic laser coagulation for twin-to-twin transfusion syndrome is challenging for anterior placenta due to the rigidity of current tools. The capacity to keep entry port forces minimal is critical for this procedure, as is optimal coagulation distance and orientation. This work introduces technological tools to this end.

METHODS

A novel fetoscope is presented with a rigid shaft and a flexible steerable segment at the distal end. The steerable segment can bend up to 90[Formula: see text] even when loaded with a laser fiber. An artificial pneumatic muscle makes such acute bending possible while allowing for a low-weight and disposable device.

RESULTS

The flexible fetoscope was validated in a custom-made phantom model to measure visual range and coagulation efficacy. The flexible fetoscope shows promising results when compared to a clinical rigid curved fetoscope to reach anterior targets. The new fetoscope was then evaluated in vivo (pregnant ewe) where it successfully coagulated placental vasculature.

CONCLUSION

The flexible fetoscope improved the ability to achieve optimal coagulation angle and distance on anteriorly located targets. The fetoscope also showed the potential to lead fetoscopic laser coagulation and other fetal surgical procedures toward safer and more effective interventions.

Subsequent fertility, pregnancy, and gynecologic outcomes after fetoscopic laser therapy for twin-twin transfusion syndrome compared with normal monochorionic twin gestations

BACKGROUND

An improved survival and quality of life for neonatal survivors after fetoscopic laser therapy for twin-twin transfusion syndrome has been reported. However, little is known about the medium-term maternal effects after fetoscopic laser therapy with respect to reproductive and gynecologic outcomes.

OBJECTIVE

The objective of this study was to document reproductive, obstetric, gynecological, and psychological outcomes in women who underwent fetoscopic laser therapy for twin-twin transfusion syndrome.

STUDY DESIGN

This was a monocentric controlled study on consecutive women who underwent fetoscopic laser therapy for twin-twin transfusion syndrome between 2007 and 2013 at the University Hospitals Leuven (cases; n = 198). Controls were women followed up during the same time period for an uncomplicated monochorionic diamniotic twin pregnancy and with an uneventful course (controls; n = 211). All patients received a questionnaire inquiring on their fertility, later pregnancies, and gynecological outcomes.

RESULTS

The response rate was 50.4% (cases: n = 95; controls: n = 109). Most baseline characteristics were similar across both groups. Women in the fetoscopic laser therapy group attempted a new pregnancy more frequently (34% [31 of 92] vs 21% [22 of 107] in controls; P < .05) and became pregnant more often (100% [31 of 31] vs 82% [18 of 22]; P < .05).We observed a shorter interpregnancy interval in cases than controls (median interval, 12 [interquartile range, 5-27] vs 24 [interquartile range, 15-30] months) (P < .05). This was also observed in cases who lost one or both fetuses or babies in the index pregnancy (median interval, 9 [interquartile range, 3.5-25.5] months; P < .05). The complication rate during subsequent pregnancies (26% [8 of 31] vs 11% [2 of 19]; P = .194) and at delivery (17% [5 of 30] vs 11% [2 of 19]; P = .554) were comparable. More women who underwent fetoscopic laser coagulation reported relevant psychological symptoms (44% [40 of 92] vs 21% [23 of 107]; P < .05). When only women in whom there was a double-surviving twin pair were considered, there were no differences in psychological symptoms compared with controls (16% [15 of 55] vs 21% [23 of 107]; P = .411). Gynecological problems were equally frequent in both groups (20% [18 of 92] vs 31% [33 of 107]; P = .069).

CONCLUSION

No adverse medium-term maternal effects with respect to fertility, obstetric, and gynecological outcomes were observed after fetoscopic laser therapy. However, these women reported more psychological or emotional problems than women with monochorionic diamniotic who did not have laser therapy, in particular when this was complicated by a fetal loss.

Learning curve for fetoscopic laser surgery using cumulative sum analysis

OBJECTIVE

To identify a learning curve and monitor operator performance for fetoscopic laser surgery for twin-to-twin transfusion syndrome using cumulative sum analysis.

DESIGN

Retrospective cohort study.

SETTING

National tertiary referral center for invasive fetal therapy.

POPULATION

A total of 340 consecutive monochorionic pregnancies with twin-to-twin transfusion syndrome treated with fetoscopic laser coagulation between August 2000 and December 2010.

METHODS

A learning curve was generated using learning curve cumulative sum analysis and cumulative sum methodology to assess changes in double survival across the case sequence. Laser surgery was initially performed by two operators, joined by a third and fourth operator after 1 and 2 years, respectively.

MAIN OUTCOME MEASURES

Individual operator performance, double perinatal survival at 4 weeks.

RESULTS

Overall survival of both twins occurred in 59% (201/340), median gestational age at birth was 32.0 weeks. Cumulative sum graphs showed that level of competence for double survival for the operators was reached after 26, 25, 26, and 35 procedures, respectively. Two operators kept their competence level and continued to improve after completing the initial learning process; two others went out of control at one point in time, according to the cumulative sum boundaries. A difference in learning effect was associated with number of procedures performed annually and previous experience with other ultrasound-guided invasive procedures.

CONCLUSIONS

This study shows that all operators reached a level of competence after at least 25 fetoscopic laser procedures and confirms the value of using the cumulative sum method both for learning curve assessment and for ongoing quality control.