Anterior Release and Posterior Spinal Fusion (AIS)

An anterior release is an operation on the front of the spine, carried out through the chest, that is done to prepare a stiff curve for correction. When I perform it, I do so as a separate procedure, and I aim to completely excise six discs across the curve. Removing those discs unlocks the front of the spine. Two things follow from that: the curve becomes considerably more flexible, so that it can be corrected more fully at the posterior operation, and, importantly, the front of the spine can be re-shaped to restore a normal thoracic kyphosis. The release itself does not straighten the spine — that is the job of the posterior fusion that follows — but it makes a good, balanced correction achievable in a spine that would otherwise resist it.

There are two reasons I turn to an anterior release, and both connect to my aims. The first is the sagittal plane. Many thoracic scoliosis curves are not just bent sideways but are also flattened, with too little of the normal forward curve of the upper back. Powerful correction from the back alone can flatten the thoracic spine further. By releasing the front of the spine and removing the discs, I create the room to rebuild a healthy thoracic kyphosis — restoring the normal front-to-back profile, which is central to a truly balanced correction. The second reason is flexibility. A large, stiff curve simply will not come round adequately from the back if it is locked at the front; releasing it first lets me achieve the coronal correction I am aiming for. When a costoplasty — a reshaping of the prominent ribs — is also required, I can perform this anteriorly at the same sitting.

The anterior release comes first, unlocking and re-shaping the front of the spine. The posterior spinal fusion then follows, and it is at this stage that the curve is actually corrected and permanently fixed into a balanced, level alignment, in both planes, with bone graft laid so the spine fuses solidly over the following months. Combining the two lets me deal with a stiff, flat curve that a single approach could not fully address, while keeping close control of both the side-to-side and the front-to-back shape. As always, the nerves are monitored throughout, and both stages are planned around the young person's general health, with particular attention to the lungs because the chest is entered.

The evidence confirms that a multi-level anterior release meaningfully increases the flexibility of a stiff thoracic curve — studies using bending films show flexibility rising substantially after release, and the post-release films closely predict the final correction. Because working on the front column restores the sagittal profile, anterior release combined with posterior fusion is particularly favoured for flat, hypokyphotic thoracic curves, where it reliably adds thoracic kyphosis that posterior-only correction tends to leave behind. The main trade-off is pulmonary: entering the chest through an open incision causes a temporary reduction in lung function, whereas keyhole (thoracoscopic) release preserves lung function far better while achieving comparable correction. Contemporary evidence also shows that modern all-pedicle-screw posterior constructs can correct many curves without a release, so anterior release is now reserved chiefly for the largest, stiffest curves and for cases where restoring thoracic kyphosis is a primary goal.

Because the chest is entered for the release, a temporary drain is commonly used for a short time and breathing is supported and monitored closely in the early days. Recovery then follows that of a spinal fusion: a hospital stay of several days, active pain relief, help to get up and move as soon as it is safe, and a graded return to normal life over the following months while the fusion becomes solid. Many young people notice they stand straighter and that the shape of the upper back looks more natural once a flat, stiff curve has been corrected. Strenuous activity and contact sport are limited during healing, and the spine is followed up over the long term.

• —Newton PO, et al. Treatment of stiff thoracic scoliosis by thoracoscopic anterior release combined with posterior instrumentation and fusion. (PMID 17937803 / PMC2173894)
• —Anterior release and posterior spinal fusion vs posterior-only fusion in AIS with large-magnitude thoracic curves. (PMC12872680)
• —In-vivo effectiveness of thoracoscopic anterior release using the fulcrum-bending radiograph. (PMC1602185)
• —The efficacy of video-assisted thoracoscopic surgery for anterior release and fusion in pediatric spinal deformity. (PMID 17152572 / PMC3207578)
• —Newton PO, et al. Is anterior release effective to increase flexibility in idiopathic thoracic scoliosis? Traction films. (PMC2229813)
• —Residual thoracic hypokyphosis after posterior spinal fusion in AIS: risk factors and clinical ramifications. (PMID 21358571)
• —Increased risk of thoracic hypokyphosis after posterior spinal fusion in AIS with thoracic double curve. (PMID 36645436)
• —CT and radiographic analysis of sagittal profile changes following thoracoscopic anterior scoliosis surgery. (PMC3495407)
• —Thoracoscopic scoliosis surgery affects pulmonary function less than thoracotomy at 2 years. (PMID 17304137)
• —The effect of surgical approaches on pulmonary function in AIS. (PMID 19494748)
• —Prospective pulmonary function comparison of anterior spinal fusion: thoracotomy versus thoracoabdominal approach. (PMID 18449037)
• —Anterior release, internal distraction and posterior spinal fusion for severe and rigid scoliosis. (PMID 23873228)
• —3D sagittal parameters can guide the indications for anterior release in thoracic AIS ≥70 degrees. (PMC11909644)