Thoracic, Lumbar & Sacral Spine Surgery After SCI: Pedicle Screws and Rods, Cages, Interbody Fusions, and Pelvic Fixation

Below the neck, the spine gets bigger, the bones get sturdier, and the hardware gets correspondingly heavier: pedicle screws the size of a small bolt, rods you can see through the skin on a thin person, cages that replace an entire vertebra. This guide covers every way the thoracic, lumbar, and sacral spine is stabilized after a spinal cord injury, from the brace-only cases to the fusions that run from the ribs to the pelvis. For the whole-spine overview, start with Spinal Fusion & Stabilization After SCI; the neck has its own guide.

Mid-Back to Pelvis, Level by Level

• Thoracic (T1–T10): twelve vertebrae, each attached to a rib. The rib cage makes this the stiffest part of the spine, so it takes a lot of force to break it, and when it does break the cord, which fills most of the narrow thoracic canal, usually takes the hit. Thoracic SCIs are the most likely to be complete.
• Thoracolumbar junction (T11–L2): the transition from stiff to mobile, and the single most common fracture site in the spine. The cord ends here in the conus medullaris (around L1–L2 in adults), so injuries at this level mix cord and nerve-root damage. Below the conus, the canal holds the cauda equina, a bundle of nerve roots that behave more like peripheral nerves and have a better chance of recovery after decompression.
• Lumbar (L3–L5): big vertebrae, big pedicles, big discs. Fractures here injure roots rather than cord.
• Sacrum (S1–S5) and pelvis: the sacrum is a wedge of fused vertebrae locked into the pelvic ring at the sacroiliac joints. Sacral fractures can tear the roots that run bladder, bowel, and sexual function, and severe ones separate the spine from the pelvis entirely (spinopelvic dissociation).

The Fracture Types & the TLICS Score

• Compression fracture: the front of the vertebral body crushes down; the back wall is intact. Usually stable; usually a brace.
• Burst fracture: the whole body explodes outward, and bone is pushed backward into the canal. The classic cause of a thoracolumbar SCI. Whether it needs surgery depends on the back ligaments and the neurological exam.
• Flexion-distraction (Chance) fracture: the spine is pulled apart from behind, typically by a lap belt in a car crash. The back ligaments or bone are torn; the abdomen is often injured too. Usually needs posterior fixation.
• Fracture-dislocation: the vertebrae have shifted on each other. Every column has failed. This is the most unstable pattern, the one most strongly associated with complete injuries, and it always needs surgery.

The TLICS score (Thoracolumbar Injury Classification and Severity Score) adds points for the fracture shape, the state of the posterior ligaments on MRI, and the neurological exam. Under 4 means a brace; over 4 means surgery; 4 is the surgeon's call. Any spinal cord or cauda equina injury adds enough points on its own to tip most cases into surgery, both to decompress and because the unstable spine has already shown it can hurt the cord.

Braces: TLSO, CTO & Jewett

• TLSO (thoracolumbosacral orthosis): the "turtle shell" or "clamshell," a molded plastic jacket in two halves that limits bending and twisting from about T6 down. Used alone for stable fractures, and after surgery by some surgeons (many no longer brace after a solid instrumented fusion). Custom-molded ones fit better and cause fewer skin problems, which matters enormously when you cannot feel the pressure points.
• CTO / CTLSO: a TLSO with a chin and chest extension (or a full Minerva) for injuries above about T6, where a body jacket alone cannot control motion.
• Jewett / hyperextension brace: a lighter three-point brace that stops you bending forward. For simple compression fractures at the thoracolumbar junction.
• Lumbar corset / LSO: for low lumbar injuries and for comfort. Provides reminder more than real stability.

Brace time is usually 8–12 weeks. In a wheelchair, a TLSO changes how you sit and where your pressure lands, so cushion and backrest choices need rechecking when it comes off.

Pedicle Screws & Rods

The pedicle is the thick stalk of bone connecting the vertebral body in front to the bony arch behind. A pedicle screw is driven through it from the back, ending deep in the vertebral body, so one screw grips all three columns. Two screws per vertebra, one rod on each side, and the screws are locked to the rods with set screws. This is the standard way to fix the thoracic and lumbar spine, and it is what "rods and screws in my back" almost always means.

The surgeon exposes the bone, places the screws by feel, X-ray, or computer navigation, corrects the alignment by bending and rotating the rods, and then packs bone graft along the roughened bone and facet joints between the screws (a posterolateral fusion). A cross-link between the rods is sometimes added for rotational strength. Screws typically span at least one, and often two, healthy vertebrae above and below the broken one, because the broken one itself may not hold a screw.

Decompression from behind, when the cord needs room: a laminectomy removes the bony roof; a transpedicular decompression or costotransversectomy reaches around the side of the cord to push or remove bone fragments that were driven into the canal from the front, without the cord being touched. In the thoracic spine, where retracting the cord is not an option, these side approaches are how the front of the canal is cleared from a posterior incision.

Burst Fractures: Short, Long & Percutaneous

Most surgical debate in this region is about how many levels to instrument, and whether to fuse at all.

• Short-segment fixation: screws one level above and one below the fracture (four screws). Less motion lost, smaller operation, but the construct is under more strain and can drift back into kyphosis, especially at the junction. Adding screws into the fractured vertebra itself ("index screws") and using a cage in front reduce that risk.
• Long-segment fixation: two levels above and two below (eight screws). Stiffer and holds alignment better; a 2025 meta-analysis of 17 trials found it maintained correction and reduced back pain better than short-segment constructs, at the cost of more fused levels. For someone with an SCI whose spine is going to carry them through decades of wheelchair sitting and transfers, many surgeons lean long.
• Percutaneous (minimally invasive) pedicle screws: the same screws placed through five or six small stab incisions using X-ray or navigation, with the rods slid under the skin. Less blood loss, less muscle damage, faster early recovery. Often done without a formal fusion: the hardware acts as an internal brace while the fracture heals on its own, and some surgeons remove it a year or two later to give the motion back. When a decompression is needed, a small midline laminectomy can be combined with percutaneous screws.
• "Damage control" fixation: in a badly injured patient with other trauma, a quick percutaneous fixation stabilizes the spine so the person can be turned and nursed safely, with the definitive fusion done days later.

Corpectomy & Cages

When a vertebral body is destroyed or a large fragment is pressing on the front of the cord, the body is removed and replaced. A corpectomy in the thoracolumbar spine is reached in one of three ways:

• Anterior, through the chest (thoracotomy) or the flank (retroperitoneal approach): the surgeon works directly on the front of the spine, removes the body and adjacent discs, and places an expandable cage or bone strut, often with a lateral plate or screw-rod construct on the side of the spine. Excellent decompression; a bigger recovery, with chest tubes after a thoracotomy.
• Lateral, minimally invasive: the same reconstruction through a smaller side incision using retractors, sparing much of the chest wall.
• Posterior-only (transpedicular or costotransversectomy corpectomy): the body is removed by working around the side of the cord from a back incision, and the cage is slid in from behind. One incision, one position, and increasingly common for trauma and tumors.

A corpectomy is almost always paired with posterior pedicle screws and rods, because a cage alone does not resist bending. The cage is packed with bone graft and, over time, bone grows through it.

Lumbar Interbody Fusions: PLIF, TLIF, ALIF, LLIF, OLIF

An interbody fusion means the disc is removed and a cage is placed between the vertebral bodies, so the fusion happens through the disc space where the bone surfaces are large and under compression. They are named for the direction the surgeon comes from. After SCI they show up for unstable low lumbar fractures, for spondylolisthesis (one vertebra slipped on another), and years later to treat worn-out levels next to an old fusion.

• PLF (posterolateral fusion): not interbody at all: screws, rods, and graft along the back of the spine only. The traditional lumbar fusion, still used for trauma.
• PLIF (posterior lumbar interbody fusion): from the back, the lamina and facets are partly removed, the nerve roots are gently held aside, and two small cages are placed into the disc space. Pedicle screws and rods on top.
• TLIF (transforaminal lumbar interbody fusion): the same idea but entered from one side through the opening the nerve exits, so the nerves are moved less. One cage, placed diagonally. The most common lumbar interbody fusion today, and the one with the most minimally invasive version (MIS-TLIF, through a tube).
• ALIF (anterior lumbar interbody fusion): through the abdomen, with the bowel and the big vessels moved aside by a vascular or general surgeon. A large cage fills the whole disc space and restores height and lordosis well; it is common at L5–S1. Sometimes stand-alone with a small anterior plate, often backed with posterior screws.
• LLIF / XLIF / DLIF (lateral lumbar interbody fusion): through a small incision in the flank, passing through the psoas muscle, with nerve monitoring. A wide cage, good for L1–L4, avoided at L5–S1 because the pelvis is in the way. Temporary thigh numbness or hip-flexor weakness from working through the psoas is common and usually resolves.
• OLIF (oblique lateral interbody fusion): a lateral approach that passes in front of the psoas instead of through it.
• Laminectomy without fusion: for a cauda equina compressed by a disc, fragment, or hematoma in a stable spine. Decompression alone, as fast as possible, gives the roots the best chance.

Sacrum & Pelvis

• Iliosacral (SI) screws: long screws driven from the outside of the pelvis across the sacroiliac joint into the sacrum, usually percutaneously under X-ray. They fix sacral fractures and the pelvic ring but do not connect to the spine.
• Lumbopelvic (spinopelvic) fixation: pedicle screws in L4 and L5 connected by rods to screws in the pelvis, either traditional iliac screws or the newer S2-alar-iliac (S2AI) screws, which start on the back of the sacrum and pass into the ilium so they sit lower and are less prominent. This bypasses the broken sacrum entirely and carries the load of the spine straight to the hips.
• Triangular osteosynthesis: lumbopelvic fixation plus an iliosacral screw on the same side, making a triangle of fixation. The standard construct for spinopelvic dissociation (U- or H-shaped sacral fractures where the spine has separated from the pelvis), which nearly always injures the sacral roots. Hardware prominence at the back of the pelvis, right where you sit and lie, is the main long-term complaint, and a real pressure-injury risk after SCI.
• Sacral laminectomy / decompression: opening the sacral canal to free roots pinched by fragments, done with the fixation when the roots are injured.

Cement, Kyphoplasty & Weak Bone

After SCI, bone below the injury thins rapidly (see Bone Health), and that changes what the hardware can hold.

• Vertebroplasty and kyphoplasty: bone cement injected through a needle into a collapsed vertebral body (kyphoplasty first inflates a balloon to restore height). For painful osteoporotic compression fractures in a stable spine, not for unstable trauma. Years after an SCI, these are the fractures people get from a hard transfer or a fall from the chair.
• Cement-augmented (fenestrated) pedicle screws: screws with side holes through which cement is injected into the vertebral body so the screw grips weak bone. Increasingly used when fusing an osteoporotic spine.
• Longer constructs, more anchors: when each screw holds less, surgeons spread the load over more of them. Pelvic anchors are added for the same reason.

Scoliosis, Kyphosis & Long Fusions

• Neuromuscular scoliosis: children injured before their growth spurt develop a curve in nearly all cases, because the paralyzed trunk muscles cannot hold the growing spine straight. Bracing slows it; a long posterior fusion, often from the upper thoracic spine down to the pelvis with screws at nearly every level, is the definitive fix once the curve is progressing. The Pediatric SCI guide covers when to watch and when to act.
• Post-traumatic kyphosis: a fracture that healed bent forward, or a fusion that lost correction, leaves a hump that shifts your center of gravity, strains the levels above, and can compress the cord again. Fixed with an osteotomy (cutting a wedge of bone out of the spine to straighten it, such as a pedicle subtraction osteotomy) and a long fusion.
• Proximal junctional kyphosis (PJK): the level just above a long fusion tips forward under the extra stress. Usually a radiographic finding, sometimes needs the fusion extended.
• Charcot spine: in people with a complete injury who have lived years without sensation, a joint below the fusion can quietly grind itself apart. It presents as sitting imbalance, a clunk or grinding sound, new back pain, loss of spasticity, or a change in bladder function or autonomic dysreflexia, typically a decade or more after injury. The treatment is a long fusion across the destroyed segment, often to the pelvis. See Living With Spinal Hardware.

Region-Specific Risks

• Screw misplacement: a pedicle screw that breaches the pedicle wall can sit against a nerve root (pain or weakness), the cord, or, in front of the spine, a blood vessel. Navigation and intraoperative CT have made this rarer. New leg pain after surgery is worth a CT.
• Loss of correction / kyphosis: the main failure mode of short constructs at the thoracolumbar junction.
• Hardware prominence and pressure injuries: rods and screw heads in the low back and pelvis sit right under the skin in a thin person and directly under the weight of sitting and lying. Prominent iliac screws are a known problem. Ask about low-profile pelvic anchors, and treat any redness over hardware as a pressure injury.
• Approach-specific issues: chest-tube days and shoulder-girdle pain after a thoracotomy; ileus (a sluggish gut) and, in men, a small risk of retrograde ejaculation after an ALIF; temporary thigh numbness or weakness after an LLIF.
• Infection: higher after SCI than in the general fusion population because operations are long, the skin over the incision is under pressure, and the urine is often colonized. Long constructs carry more risk than short ones.
• Autonomic dysreflexia during and after surgery in injuries at T6 and above. Make sure anesthesia knows. See the AD protocol.

Recovery in a Brace

• Log-rolling and a TLSO for the first weeks if your surgeon braces; many do not after a solid instrumented fusion, so ask rather than assume.
• Restrictions on bending, lifting, and twisting for roughly 6–12 weeks. Transfers and wheelchair pushing need to be discussed specifically: a slide-board transfer twists the trunk, and a depression transfer loads it. Therapists will teach modified versions.
• Follow-up X-rays at about 6 weeks, 3 months, 6 months, and a year; a CT if there is any doubt about the fusion. Fixation-without-fusion constructs may be removed at 12–24 months.
• Seating needs a fresh evaluation once the brace is off: your trunk is now stiff in a different way, and your pressure map changed.

Questions to Ask

• Which levels are instrumented, and which are fused? Is the hardware meant to stay or to come out?
• Short segment or long segment, and why did you choose it for me?
• Was the canal decompressed, and from which side?
• Where exactly is the hardware closest to the skin, and how do I protect it in the chair and in bed?
• How will my bone loss below the injury affect the screws, and is cement augmentation worth it?
• What are the transfer and pushing restrictions, in writing, for my therapy team?
• What signs should make me call: new leg pain, a clunk, a change in sitting balance, new AD?

Sources & Further Reading

• Efficacy and safety of posterior short-segment versus long-segment pedicle screws fixation for thoracolumbar burst fractures: a systematic review and meta-analysis (2025)
• Percutaneous pedicle screw fixation for thoracolumbar fractures
• PLIF and TLIF (Interbody Fusion) and Lateral Lumbar Interbody Fusion (OrthoInfo, American Academy of Orthopaedic Surgeons)
• Emerging Techniques in Lumbopelvic Fixation: Biomechanical and Clinical Perspectives; Minimally Invasive Fixation for Spinopelvic Dissociation: Percutaneous Triangular Osteosynthesis
• TLICS Classification of fractures (Radiology Assistant) and Denis Classification (StatPearls)
• Charcot spinal arthropathy: an increasing long-term sequel after spinal cord injury with no straightforward management (Spinal Cord Series and Cases)
• AO Surgery Reference: Spine trauma (thoracolumbar and sacral sections)

This is not medical advice. Spine surgery decisions depend on the exact fracture pattern, your neurological exam, your bone quality, and your overall health. The names and techniques here are to help you understand and question what your surgical team proposes, not to replace that conversation. Practice varies by surgeon and institution.