Surgical Techniques: Cervical Osteotomies: Modified Cervical SPO

Abstract

Smith-Petersen osteotomy (SPO) was first described in 1945 for patients with a kyphotic deformity secondary to rheumatic conditions (i.e. ankylosing spondylitis or rheumatoid arthritis). This technique uses the posterior half of the vertebral body and longitudinal ligament (PLL) as the fulcrum to obtain correction. This results in a shortening of the posterior column and a lengthening of the anterior column. This chapter describes a modified SPO technique for treatment of severe cervico-thoracic kyphotic deformities (CTKD). The osteotomy is performed at C7/T1 level. The technique consists in a complete resection of the C7 lamina, inferior portion of C6 and superior portion of T1 laminae. The cervical spine is instrumented from C3 to C6 and thoracic spine from T1 to T5. Malleable temporary rods are used to control coronal and sagittal plane movement during correction of the deformity while allowing extension at the cervico-thoracic junction. This technique is commonly applied in patients with ankylosing spondylitis but can be used in patients with other etiologies. Technical details are presented with advice on how to prevent common pitfalls with this technique.