Conjoined legs: Sirenomelia or caudal regression syndrome?
A 12-year-old boy presented with fusion of lower legs above the ankle joint. Bilateral femur and upper two-third of tibia and fibula were separated. There was fusion of both legs in the lower one third of leg []. The boy weighed 23 kgs at the time of admission. The parents were nonconsanguineous. There was no history of maternal diabetes and patient had a breach presentation with immediate birth cry. Both knees had flexion deformities (right: 10° and left: 25° as measured by 180° goniometer). Both legs were short (left shorter than right). Both feet were rudimentary. The right foot had a valgus rocker-bottom deformity. All toes were present but rudimentary. The left foot showed absence of all toes. Physical examination showed left tibia vara. The chest evaluation in sitting revealed pigeon chest and elevated right shoulder. There was expansion of 2, 3, and 3 cm in axilla, nipple, and xiphisternum levels, respectively. Posterior examination of the trunk showed thoracic scoliosis with convexity to right. He was having no other physical anomalies in the skull, face, and lumbar region.\nMagnetic resonance imaging of spine showed no abnormality in soft tissue planes that is expected from CRS or sirenomelia-like blunted sharp ending of spinal cord or hypoplastic sacrum. Ultrasound of abdomen and pelvis ruled out any visceral anomalies. Color Doppler imaging for both lower limbs showed that anterior tibial, posterior tibial, and peroneal arteries were small in caliber and nontraceable throughout their extent but showed normal triphasic flow pattern in visualized segments. Bilateral external iliac, common femoral, superficial femoral, profunda femoris, and popliteal arteries were normal in caliber and blood flow.\nThe superficial and deep veins were competent in both sides and showed spontaneous phasic flow with adequate response to valsalva and augmentation. There was no evidence of deep venous thrombosis (DVT), arterial venous malformation (AVM) and aneurysm.\nA multidisciplinary surgical team, composed of a plastic surgeon, a vascular surgeon, and an orthopedic surgeon, achieved complete separation of the lower limbs. The typical zigzag incisions were marked between the limbs, Z-plasty of skin was performed [] with independent vascular and nerve supplies. The vascular surgeon identified the anteriortibial, posterior tibial, and peroneal arteries on both the limbs. Intraoperatively, it was found that femurs, tibias, and ﬁbulas were normally represented. Muscles seemed to be present and tonic. After separation, the left side tibia was found to be posterolaterally angulated for which a corrective osteotomy was done and fixed with K-wire to make the feet plantigrade []. Pulse oximeters were helpful during the surgical procedure to assess the viability of the separated limb. Wound closure was performed with split thickness skin grafting from anterolateral thigh. The skin-graft donor site was closed with absorbable sutures. A generous amount of antibiotic ointment was directly applied to the skin graft, and the incisions were followed by a nonadherent dressing material. Dressing was changed after 72 h. The boy had two separate legs with a good aesthetic and functional result [].\nPostoperative physiotherapy consisted of active movements after the skin grafts had settled in by 6 days. The child was instructed to massage the scars to soften them. Once the scar was well established, a cast was applied to stretch the knee flexion contracture which was mostly of soft tissue origin. Strengthening exercises, balance retraining, and gait reeducation were also introduced as part of therapy.\nAfter the surgery, the child demonstrated grade 3 muscle strength in bilateral quadriceps. The arm span was 141 cm but the child measured only 114 cm in total vertical height The hip range of motion was within normal limits and the child was able to stand on both feet and was able to walk with prosthesis []. The prosthesis prescribed was partial type prosthesis for right side and Syme's type of prosthesis for left side along with distal weight bearing socket having soft lining and ethaflex extension for foot and a pair of normal shoes. Anterior strap with pad was given above the bulbous end for suspension.\nAt 6 months’ followup after the operation, the child presented with excellent general condition and good state of healing of the skin scars at the lower extremities, without any evidence of skin retraction. At the time of this writing, the boy was 13-year-old and growing normally. The parents were instructed to go for a detailed assessment to rule out the possibility of any urologic, congenital heart defects and any neuroblastoma that might have coexisted.