Conjoined Twin Separation: Review of 30-Year Case Experience and Lessons Learned

BACKGROUND

Conjoined twinning is a rare medical phenomenon, and numerous challenges remain with respect to surgical separation and reconstruction. The purpose of this study is to present a detailed discussion of the authors' institutional experience with eight conjoined twin separations over the past three decades, focusing on challenges and lessons gleaned from these cases.

METHODS

The records of all patients who underwent conjoined twin separation at The Hospital for Sick Children in Toronto, Ontario, Canada, from 1984 to 2018 were retrospectively reviewed.

RESULTS

Eight sets of conjoined twins were analyzed. Half of the sets [ n = 4 (50 percent)] were female. There were four sets (50 percent) of ischiopagus twins, three sets (37.5 percent) of omphalopagus twins, and one set (12.5 percent) of craniopagus twins. The median age at separation was 6.75 months. The mean durations of intensive care unit and hospital stay were 14.1 ± 12.9 days and 4.9 ± 4.8 months, respectively. Mean length of follow-up was 6.7 ± 4.4 years. Three deaths occurred in our series, with an overall survival rate of 81 percent. Two sets of twins experienced expander-related complications such as infection and bowel perforation. Three twins required reoperation because of flap necrosis or dehiscence after separation.

CONCLUSIONS

The authors' results highlight the unique nature of each operation and the great ingenuity required in managing the particular considerations of each case and also adhering to a systematic approach of evaluation and planning. A number of novel strategies were used at the authors' center and have now become commonplace. The lessons learned from such procedures may improve care for future generations of patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Conjoined twins: From conception to separation, a review

Conjoined twins are suggested to result from aberrant embryogenesis. The two main theories proposed to explain the phenomena are fission and fusion. The incidence rate is 1 in 50,000 births; however, since about 60% of the cases are stillborn, the true incidence is approximated at 1 in 200,000. There is a higher predisposition towards female than male gender with a ratio of 3:1. Conjoined twins are classified based upon the site of attachment. The extent of organ sharing, especially the heart, determines the possibility and prognosis of a separation procedure. Meticulous preoperative evaluation, planning, and preparedness of the team are crucial for a successful separation. Separation of conjoined twins poses several technical, legal, and ethical issues. Clin. Anat. 30:385-396, 2017. © 2017 Wiley Periodicals, Inc.

Urological management

The pediatric urologists role is confined to ischio-, para-, and pygopagus conjoined twins. The aim is to preserve renal function, to address problems with urinary continence, and to optimize genital issues with particular reference to sexual and reproductive function. Full urological imaging is essential prior to separation for planning and for the operation itself.

The separation procedure

The various stages of the separation are carefully planned but despite this, variations which will change the schedule of the procedure may exist. In general the operation commences on the opposite side from the main procedure and then the twins are turned for the remainder of the operation. Each type of conjoined twin is different but basically thoracopagus involves the hearts, omphalopagus involves the liver and small intestine and ischiopagus involves the large intestine and genito-urinary system. Our results are presented together with interesting cases from which lessons have been learned.