Efficacy of Surgical Treatment by Different Pedicle Screw Systems in Pediatric Neuromuscular Spinal Deformity

Overview

This study was sponsored by Federal state budgetary institution "Russian scientific center for traumatology and orthopedics" n.a. acad. G.A. Ilizarov" of the Ministry of Health of Russian Federation. The study will take place at this center. It is expected to enroll 70 patients aged 6-25 years with NMD, all of whom will be subjected to thoracic and lumbar spinal deformity surgery. Patients will be divided into two groups depending on skeletal maturity. The degree of skeletal maturity will be determined on the basis of an X-ray study of spinal and pelvic bones. The type of surgical correction will depend on the group.

First group of patients: local dorsal access. Cranial access: at the level of posterior Th2 5 structures and caudally at the level of L4-S2 vertebrae with exposure of posterior upper spines of iliac wings. Skeletization of vertebrae will be done within transverse processes. Pedicle support points are set bilaterally cranially at each segment level for the space of 3 segments. Caudal support base is formed with pedicle screws in lateral masses of the sacral bone or iliac crests at the level of L5-S1 vertebrae. Control fluorography is performed in two standard planes in order to control screw position. Two "dynamic" rods are formed on the basis of the distance between screw heads allowing 2 cm for distraction; these are two rods connected with a longitudinal connector and bent following the normal sagittal spine profile. After that, channels are formed on both sides under m. erector spinae in the cranial/caudal direction. Pre-bent rods with connectors are placed into the prepared channels. The metal construct is stabilized with internal set screws. If necessary, the construct may be stiffened with crosslinks. Control fluorography is performed in two standard planes in order to control implant position and evaluate correction. The intervention completes with local dorsal spinal fusion with an autobone at the level of base screws. The wound is sewn up in layers tightly. Group two: dorsal access to the posterior column is gained in accordance with the preoperative plan. The access length depends on the instrumentation area. Vertebral skeletization is performed within transverse processes. Subgroup 1 - pedicle support points are set bilaterally at each segment level. Subgroup 2 - pedicle support points are set bilaterally in every second segment. Segmented instrumentation of 3 cranial segments to prevent dislocation of metal construct elements at the level of Th2-4 or Th3-5 vertebrae is a special measure. Similar to group I, caudal support base is formed with pedicle screws in lateral masses of the sacral bone or iliac crests at the level of L5-S1 vertebrae. Control fluorography is performed after that in two standard planes in order to control screw position. Segmented facetectomy is recommended for additional spine mobilization. Pre-bent rods are placed into support points. Deformity correction is performed by means of a translational maneuver, segmented distraction (concave side) and compression (convex side). The metal construct is stabilized with internal set screws. If necessary, the construct may be stiffened with crosslinks. Control fluorography is performed in two standard planes in order to control implant position and evaluate correction. The intervention completes with dorsal spinal fusion with an autobone along the implants. The postoperative bed is subjected to Redon drain. The drainage is exteriorized to the skin via a separate puncture. The wound is sewn up in layers tightly.