PSF Not to the Pelvis (Neuromuscular)

Neuromuscular scoliosis develops when weakness or imbalance of the trunk muscles allows the spine to curve. In some patients — particularly those who retain some walking ability, and in certain conditions such as milder cerebral palsy or some cases of muscular dystrophy — the pelvis remains relatively level, and the lower part of the curve does not extend deeply into the lowest lumbar segments. In these situations the spine can be corrected and fused without anchoring into the pelvis, stopping the fusion at the lower lumbar spine instead. The rationale for stopping short is to gain the benefits of correction and stability while preserving some movement at the very bottom of the spine and the hip-pelvis region, which can matter for walking, transfers and comfort, and while avoiding the additional operating time, blood loss and complications that come with pelvic anchors. The decision is guided by the underlying diagnosis, the degree of pelvic tilt, the flexibility of the lower curve, whether the child walks, and the pattern of the deformity — not by any single measurement.

This is what is generally done, although techniques vary between surgeons and centres. The operation is a posterior spinal fusion carried out through the back. The spine is exposed, and anchors — most commonly pedicle screws — are placed into the vertebrae on both sides along the length of the curve, with the lowest anchors sited in the lower lumbar spine rather than the pelvis. Two contoured rods are attached and used to derotate and straighten the spine and to balance the trunk over a level pelvis. Bone graft is laid along the spine so that the instrumented segments gradually fuse into one solid column over the following months. As with all neuromuscular spinal surgery, the operation is planned carefully around the child's general health, with attention to anaesthesia, blood management and monitoring of the nerves throughout. A key part of the planning is choosing the lowest level to fuse — an important judgement, because stopping at the right level aims to leave a balanced spine that will not tip out of line or develop a new curve below the fusion.

The literature shows that a well-selected fusion stopping short of the pelvis can achieve good curve correction and a balanced trunk with a shorter, less invasive operation than fusion to the pelvis. Comparative studies report that correction of the main curve is broadly similar whether or not the pelvis is included, with the main difference being in correction of pelvic obliquity, which is somewhat greater when the pelvis is fused. Reviews highlight that extending to the pelvis carries roughly double the reoperation rate in some series and a higher burden of implant-related problems, which is part of the rationale for stopping short when the pelvis does not need to be included. The key risk of stopping short is that, if the level is misjudged or the pelvis was more involved than appreciated, the tilt can persist or a curve can develop below the fusion, sometimes requiring further surgery. This is why patient selection — guided by disease, walking ability and the flexibility of the lower spine — is so central, and why the evidence favours individualised decisions rather than a fixed rule.

Recovery follows a similar path to other major spinal fusions, supported by the whole team. After the operation the child is monitored closely, with active pain relief, and is helped to get up and move as soon as it is safe. For children who walk, an important aim is to protect and support that ability, and physiotherapy helps rebuild confidence and function. A hospital stay of around one to two weeks is common, and the fusion takes several months to become fully solid, during which strenuous activity is limited. Many families notice better posture, more even sitting or standing, and easier day-to-day function once recovery is underway. Progress can feel gradual at first, and it is normal for strength and confidence to build over the weeks and months that follow, with long-term follow-up of the spine.

This is major surgery, and in children with neuromuscular conditions it carries real risks that the team discusses fully beforehand — including bleeding, infection, anaesthetic and breathing problems, and implant-related issues. A consideration specific to stopping short of the pelvis is the small risk that the pelvis remains or becomes tilted, or that a new curve develops below the fusion, which can occasionally require revision surgery. Balancing these possibilities against the advantages of a shorter, less invasive operation is exactly why the choice of the lowest fused level is made so carefully for each individual. This page is educational and does not recommend or advise for or against surgery, or any particular fusion level, in any individual case.

• —When to perform fusion short of the pelvis in patients with cerebral palsy? Indications and outcomes. (PMC10106181)
• —Effect of pelvic fixation on ambulation in children with neuromuscular scoliosis. (PMID 36159626 / PMC9453276)
• —Pelvic vs lumbar fusion in neuromuscular scoliosis — a systematic review. (PMID 40173209 / PMC11966631)
• —The indication of fusion to the pelvis is based on the underlying disease rather than on pelvic obliquity. (PMID 37750950)
• —Current concepts in the treatment of neuromuscular scoliosis: clinical assessment, treatment options, and surgical outcomes. (PMID 35084206 / PMC9047085)
• —Clinical issues in indication, correction, and outcomes of surgery for neuromuscular scoliosis in the pedicle screw era. (PMC8987549)
• —Surgical correction and fusion using posterior-only pedicle screw construct for neuropathic scoliosis in cerebral palsy: three-year follow-up. (PMID 19444065)
• —Surgical complications in neuromuscular scoliosis operated with a posterior-only approach using pedicle screw fixation. (PMC2685769)
• —Surgical and long-term functional outcomes of patients with Duchenne muscular dystrophy following spinal deformity correction. (PMC10292064)
• —Impact of scoliosis surgery on pulmonary function in patients with muscular dystrophies and spinal muscular atrophy. (PMID 32012473)
• —Posterior spinal fusion for scoliosis in Duchenne muscular dystrophy diminishes the rate of respiratory decline. (PMID 17304138)
• —Comparison of survival between surgical and non-surgical treatment in Duchenne muscular dystrophy scoliosis. (PMID 32535073)
• —Quality of life after surgery for neuromuscular scoliosis. (PMC3662264)
• —Surgical advances in the treatment of neuromuscular scoliosis. (PMC4017305)
• —Surgical management of neuromuscular scoliosis in paediatric patients: experiences from a tertiary centre multidisciplinary team. (PMC11836852)