A study of functional spinal motion in women after instrumentation and fusion for deformity or trauma

Photographs were used to measure the residual spine motion in 71 women who had undergone spine fusion and instrumentation for spinal deformity or trauma.

To accurately define the ability of the patient to flex, extend, and bend to the right and left, thus providing the surgeon some accurate information rather than speculation regarding spinal motion.

The 71 patients had undergone spine fusion with instrumentation for scoliosis, kyphosis, or spine trauma. The average age of the patient at surgery was 22 years, ranging from 11 years to 62 years. The average time since surgery was 6 years, ranging from 1 year to 32 years. Each patient had six views photographed: flexion, extension, right and left side bending from the front, and right and left side bending from the back. Each photograph was measured independently by two research assistants. A total of 852 photographs were analyzed.

The average degree of right side bending was 22 degrees, that of left side bending was 23 degrees, that of flexion was 111 degrees, and that of extension was 30 degrees. For the 59 patients who underwent fusion of seven levels or more and who were fused down to T12, L1, L2, L3, or L4, there was no correlation of the range of motion with the lowermost level of fusion, except in patients with fusion to L4 who had significantly less motion. Flexion was primarily a function of hamstring tightness and was best in those who exercised regularly (aerobics, gymnastics, ballet), regardless of the number of levels fused or the lowermost level of fusion.

Typical spine fusions for deformity produce a moderate loss of functional motion, except in patients who undergo fusion to L4 who lose much more. The technique of analysis was found to be highly accurate and reproducible.