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Common spinal operations: definitions and terms explained

Spinal Fusion - surgically preparing two or more surfaces or vertebrae to become artificially joined over time, typically with bone graft joining the bony surfaces. The goal is to stabilise a painful, poorly aligned or dysfunctional (e.g. pinching nerves) motion segment. Common reasons (indications) that spine fusion is performed is due to spinal malalignment (e.g. spondylolisthesis, kyphosis or scoliosis), instability (e.g. trauma or spondylolysis - stress fractures), neuroforaminal spinal stenosis (where the fusion aims to increase the disc height by distracting the segment, thereby opening up the tight and collapsed tunnels impinging the nerves), persistent disc related or segmental pain after multiple operations that hasn't responded to conservative measures (to stop the painful segment moving.) Spinal fusions without an adequate indication (e.g. for back pain without a precision diagnosis) are generally discouraged as they are not as successful as surgery that is indicated and well planned for.



Posterior spinal fusion - fusion achieved by preparation of joint surfaces and facet joint, transverse process and lamina and packing with bone graft. Often held with screws either through the pedicles or local bony anatomy (e.g. cortical screws)

Lumbar interbody fusion (LIF) - spinal fusion achieved by insertion of a spacer implant into the intervertebral space (between the discs) with or without screws/plates to stabilise.

Anterior LIF or ALIF - LIF performed through an incision at the front of the abdomen with an approach to the front of the spine around the internal abdominal organs with a front on trajectory to the disc. 

Direct Lateral or Extreme Lateral LIF - DLIF/XLIF - LIF performed through an incision at the side of the abdomen with a perpendicular trajectory to the disc.

Oblique LIF or OLIF - ~45 degree trajectory to the disc through the abdomen in front of the psoas muscle.

Posterior LIF or PLIF - LIF performed by removing facet joints and shifting the nerve sac to access the back of the disc with disc clearance being back to front around the nerve sac.

Transforaminal LIF or TLIF - performed by accessing the corner of the disc under the exiting nerve root off to the side of the back of the spine.

360 degree fusion - combinations of LIF and posterior fusion.

Total disc replacement - an artificial protheses intended to maintain spinal motion as opposed to fusion, after clearance of an intervertebral disc.

'Hybrid' - Combination of fusion and disc replacement

Decompression - removing pressure off spinal nerves, generally by removing one or more of a protruding disc, enlarged ligament, bony spurs or overgrown joints. Laminectomy (removing the lamina), discectomy (removing part of a disc) and foraminotomy (enlarging the tunnel for the nerve, or foramen) are all forms of decompression.

Discectomy - surgically paring back or shaving a prolapsed disc touching a nerve. A sequestrectomy is typically performed, only shaving the external disc sitting behind the posterior longitudinal ligament. An aggressive discectomy aims to remove any loose or devitalised pieces in the disc space. Both have pros and cons.

Foraminotomy / Facetectomy - refers to enlarging the space around an exiting nerve root by removal of bony and joint around the foramen and /or facet joint. Usually done on one side but can be bilateral.

'Micro' - refers to procedure done under magnification such as a microscope or loupe glasses.

'Minimally invasive' / 'keyhole' - refers to procedure done with smaller incisions and less muscle damage than conventionally available operations. While appealing, there are also potential downsides to such approaches.

Navigated & Robotic  - Refers to the computer assisted and guided implantation of spinal hardware often calculated and referenced off the patient's bone anatomy from imaging such as CT scans or paired-calibrated Xrays in theatre.

Radiofrequency ablation / neurotomy / denervation / pulsing - all refer to targeted procedures using needles through the skin to alter pain fibres in nerves using radiofrequency energy delivered around the tip of a needle. Ablation aims for permanent destruction of a nerve (e.g. to an arthritic joint) whereas pulsing is less permanent and aims to just desensitise a sensitive nerve.

Spinal instrumentation or stabilisation - refers to insertion of spinal metalwork for the purpose of stabilising a segment. This may be to promote bony fusion (by holding the segment still and supported) or in the context of trauma such as unstable fractures.

Laminoplasty - removing the lamina then replacing it 'hinged open' with metal plates, to create more space.

Coccygectomy - removal of part of the coccyx bone.

Please see links below to commonly performed spinal procedures:

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