Vertebral Column Resection (VCR) in Congenital Kyphoscoliosis (CKS)

Overview

Congenital spinal deformities (CSD) are caused by early embryologic errors in vertebral column formation. Spinal cord malformations are present in approximately one third of patients, even associated cardiac, renal, and genitourinary organ system anomalies in more than half of patients. Functional activity and health-related quality of life (HRQOL) are severely affected in adolescents with neglected severe congenital kyphoscoliosis (CKS) progressive curves in developing countries. Different strategies are described with two main principles; I- Prophylactic surgeries like hemi-epiphysiodesis or in situ fusions that will cease worsening or allow progressive correction over time, II- Corrective surgeries like reconstructive osteotomies and spinal fusion with or without spinal resection. The perfect show in management of congenital spinal deformities is to pick up the curves at early stages where a prophylactic treatment can be achieved with minimal risk to the spinal cord, but certainly many cases are quite aggressive or come late enough where corrective surgeries and even spinal column resection is the only valid plan. A posterior-based vertebral column resection (VCR) is considered to be the preferred approach in the treatment of rigid, severe, and complex spinal deformities, however the difficult and lengthy nature of the procedure require assistance from experienced and well trained team. It is relatively safe but challenging technique, that allows for dramatic radiographic correction and clinical improvement. It also carries a complication rate of 10.2% as profound blood loss, iatrogenic neurological deficit and late junctional kyphosis.

Preoperative Details : Every patient is examined for 1- Shoulder balance 2- Pelvic balance 3- Thoracic hump 4- Neurological examination. Also preoperative whole-spine X-ray anteroposterior and lateral view radiographs in erect position are obtained for accurate preoperative planning. Three-dimensional Multi-Slice Computed Tomography (MSCT) scan is obtained to delineate posterior vertebral column pathoanatomy before surgery. Whole-spine MRI is obtained for declaration of any associated spinal cord malformation. Operative Details : Appropriate patient positioning on the operating frame to avoid excessive pressure points in the axilla, allow the abdomen to hang free, and to maintain stability of the trunk during surgery. Standard posterior exposure is performed, and pedicle screws are placed using a free-hand technique as. The exposure at the osteotomy site is extended laterally to resect a portion of the medial ribs to enhance the exposure of the vertebral body to be removed. Once adequate exposure is achieved, a wide laminectomy is completed from the pedicles of the proximal vertebra to the pedicles of the distal vertebra. Use of tranexamic acid to minimize osseous bleeding during these lengthy surgeries is advisable. At this point, a short rod is placed into the pedicle screws of 1 side to include at least 2 pedicle screws proximally and 2 pedicle screws distally, to provide stability during the osteotomy. Once this rod is secured, the proximal and distal discs are removed and the vertebra to be removed is outlined. Then, the osteotomy is started from the pedicle on the contralateral side, and extending into the body. The exiting nerve roots are tied and transected at the thoracic levels, gently retracted at the lumbar levels. The removal of vertebral body is proceeded using Kerrison rongeurs and osteotomes as necessary. After adequate removal, another rod is placed to the already osteotomized side, and secured. At this point the rod on the other side can be removed or kept in place, depending on the amount of expected instability. The resection carried similarly on the contralateral side. The posterior wall of the vertebral body is kept intact until the very end of the osteotomy. After the removal of the vertebral body and discs, using a reverse cutting curette the posterior wall is fractured with anteriorly directed blows and removed using rongeurs. The endplates of the neighboring vertebrae are cleaned off of any remaining cartilage to expose bone surfaces to achieve fusion. The anterior defect is augmented with morsellized cancellous graft with or without the use of a titanium mesh cage, depending on the width of the void. After the completion of resection, deformity correction is carried out and the posterior instrumentation system is secured using pedicle screws. Application of Wakeup test to detect any on-table neurology. Decortication followed by addition of remaining autograft and allograft to the fusion is performed. Posterior wound closure is performed over a drain. Postoperative Details : Follow-up protocol is carried out after 2 weeks, 3 months, 1 year, and 2 years postoperatively with whole-spine X-Ray radiographs in erect position, and after 1 year with Multi-Slice Computed Tomography (MSCT) scan to assess fusion rate.