Allowing Standing and Assisted Steps in a Patient With Renshaw Type IV Sacral Agenesis

Abstract

Case: A 6-year-old boy with a Renshaw type 4 sacral agenesis presented paraplegia and rigid, "Buddha-like" lower-limb contractures, including severe knee pterygia, which made crawling and sitting difficult. Staged surgical treatment involved bilateral knee disarticulation, soft tissue surgery, and bifocal femoral osteotomies for lower-limb reorientation. At 18 months postoperatively and after prosthetic fitting, the patient can stand and take steps with assistance. Conclusion:This effective surgical strategy achieves standing in a troublesome orthopaedic congenital condition. The intervention should be tailored to specific orthopaedic disorders and the wishes of patients and families, aiming to improve function. Sacral agenesis (SA) is a rare congenital malformation of the sacrococcygeal bone 1 that encompasses a wide spectrum of malformations of the caudal region of the spine. When associated with gastrointestinal or urogenital malformations it is referred to as caudal regression syndrome (CRS) 2 . Common orthopaedic abnormalities associated with SA are kyphoscoliosis, spinopelvic instability, and, in more severe cases, lower-extremity paraplegia with rigid flexion-abduction hip contractures, knee pterygia, and foot deformities 3 . This rigid, "Buddha-like" lower-limb position causes great functional impairment that not only prevents walking and standing but also inhibits comfortable sitting. If left untreated, as the child grows, wider chairs would be needed to accommodate the position and over time this would impede access through doorways and mobility even at home.The estimated incidence of SA is between 1 and 5 cases per 100,000 births 1 . The main risk factor found is maternal diabetes, which increases the risk of SA 20-fold 1 . Other related risk factors are folic acid deficit 4 , multiple pregnancies, smoking 1 , and retinoic acid intake 5 . A failure of neurulation caused by a vascular deficit in Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/C103).