Fusionless scoliosis correction using a shape memory alloy staple in the anterior thoracic spine of the immature goat

Spine (Phila Pa 1976). 2004 Sep 15;29(18):1980-9. doi: 10.1097/01.brs.0000138278.41431.72.


Study design: Experimental scoliosis was created in goats and then treated using anterior thoracic stapling.

Objective: To correct, without fusion, a progressive idiopathic-type scoliotic deformity in an immature goat model using a shape memory alloy staple.

Summary of background data: Fusionless scoliosis treatment techniques, using minimally invasive approaches to the anterior thoracic spine, provide theoretical advantages over currently available forms of treatment.

Methods: Experimental scoliosis was created in 40 goats using a posterior asymmetric tether with convex rib resection and concave rib tethering for a period of up to 15 weeks. Twenty-seven goats with progressive deformities were used for subsequent study and randomized into 4 treatment groups: group I, anterior thoracic stapling with removal of the posterior tether; group II, removal of the posterior tether only; group III, anterior thoracic stapling with persistent posterior tethering; and group IV, persistent posterior tethering with no treatment. The treatment period lasted an additional 6 to 14 weeks. Staple backout was graded radiographically. After killing the goats, histology and disc biochemistry analyses were conducted.

Results: The goats in group I corrected from an initial 57 degrees of curvature to 43 degrees over the duration of the treatment period. Group II goats, which served as a control for group I, corrected from 67 degrees to 60 degrees during the treatment period. Group III goats demonstrated a modest correction from 65 degrees to 63 degrees with the stapling procedure, whereas group IV goats (controls for group III) progressed from 55 degrees to 67 degrees with a persistent posterior tether during the treatment period. The difference between the correction in group III and progression in group IV was statistically significant (P = 0.002). Complications were limited to partial staple backout in 27% of 56 staples.

Conclusions: The results of this study support the efficacy of an anterior thoracic staple in correcting moderately severe scoliosis and halting the progression of more malignant scoliosis without fusion in a goat model.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alloys
  • Animals
  • Cold Temperature
  • Disease Progression
  • Electrocoagulation
  • Equipment Design
  • Female
  • Goats
  • Hot Temperature
  • Hydroxyproline / analysis
  • Implants, Experimental*
  • Internal Fixators*
  • Intervertebral Disc / chemistry
  • Nickel / analysis
  • Proteoglycans / analysis
  • Random Allocation
  • Scoliosis / surgery*
  • Surgical Stapling* / instrumentation
  • Sutures*
  • Thoracic Vertebrae / surgery*


  • Alloys
  • Proteoglycans
  • Nickel
  • Hydroxyproline