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Diagnostic Radiology · Spine

Postoperative spine

Postoperative Spine

Diagnostic imaging of the operated spine is essential for monitoring spinal alignment, implant positioning, and bone healing status. To correctly interpret images, the physician must understand the type of procedure performed and the characteristics of the hardware used.

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Goals of SurgeryDecompression of neural structures, segmental stabilization, and tumor excision.
Spinal FusionMetal hardware serves merely as temporary support until complete bone healing occurs.
RadiolucencySynthetic polymer cages are visualized via metal markers.
3 min readFor medical studentsUpdated Sep 25, 2026
Material prepared by WhiteCoat Pro editorial team based on platform study guidesReviewed by medical editor: Aulov A. A., general practitioner · 09/24/2026

Principles of Spine Surgery

Spinal surgical interventions pursue three primary goals:

  1. Decompression of neural structures (decompression of neural structures). Performed to remove herniated discs, widen a stenotic canal, or extract bone fragments displaced during a fracture.
  2. Stabilization of the spinal column (stabilisation of the spinal column). Necessary to relieve movement-induced pain, provide support following bone structure resection, and prevent deformities.
  3. Excision of spinal tumours (excision of spinal tumours).

Decompression Methods

Various types of resection (often combined) are used to free nerve roots and the spinal cord:

  • Disc procedures: discectomy (discectomy) and microdiscectomy.
  • Access to the canal: laminotomy (removal of the lamina edges), hemilaminectomy (unilateral lamina resection), flavectomy (excising the ligamentum flavum).
  • Canal widening: laminoplasty (lamina osteotomy creating a gap), bilateral laminectomy (complete removal of posterior structures — "roof removal"), facetectomy (excising the zygapophyseal joint).
  • Root decompression: foraminotomy (in the intervertebral foramen zone).
  • Extensive resections (for trauma and tumors): pediculectomy (pedicle resection), corpectomy (vertebral body resection), vertebrectomy (removal of the entire vertebra).
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Stabilization and Bone Grafting

Stabilization is achieved via instrumentation (placement of translaminar, pedicle screws, rods, plates, hooks) and bone grafting. The main rule: metal hardware serves as a temporary framework until continuous bone fusion (bone fusion) develops.

Materials for Spinal Fusion:

  • Autografts: harvested from the patient's own body (iliac crest, tibia, or fibula). Cancellous chips stimulate osteogenesis, while cortical bone provides support.
  • Allografts: donor tissue (femoral rings, fibular struts).
  • Synthetic substitutes: recombinant human bone morphogenetic protein (BMP), demineralized bone matrix (DBX), ceramics.
  • Synthetic cages: replace cortical bone during interbody fusion. Available in metal (titanium) and non-metal radiolucent materials (PEEK, polylactic acid, carbon). The cage cavity is filled with bone chips.

Postoperative Imaging Findings

Surgical approaches may be anterior, posterior, or combined. Radiographs and CT scans allow evaluation of the procedure type:

  • Following corpectomy (e.g., for chordoma), a massive autograft (often from the iliac crest) is visualized, fixed with an anterior plate and posterior screws with rods.
  • Following ACDF (anterior cervical discectomy and fusion), a cortical graft or cage is visible in the interbody space.
  • In lumbar interbody fusions (PLIF, TLIF), cages are visualized. If the cage is radiolucent (radiolucent cage), its position is determined by built-in metal markers (radiopaque dots/pins).
  • Posterior fusion is often accompanied by the placement of crushed bone chips (bone chips) posterior to the fixation hardware elements.

Briefly: answers to topical questions

What types of interbody fusion are used at the lumbar level?

Anterior, posterior, transforaminal, direct lateral, and oblique lateral types of lumbar interbody fusion are utilized.

  • Anterior lumbar interbody fusion (ALIF) — possesses the greatest corrective capability (up to 15-20° per segment).
  • Posterior lumbar interbody fusion (PLIF) — has the lowest correction capability (approximately 7°).
  • Transforaminal lumbar interbody fusion (TLIF) — is also characterized by minimal correction capability.
  • Direct lateral interbody fusion (DLIF) — provides moderate sagittal plane capabilities and good frontal plane capabilities.
  • Oblique lateral interbody fusion (OLIF) — is similar to DLIF in its corrective characteristics.

Which imaging signs indicate instability of installed pedicle screw instrumentation?

The primary imaging sign of pedicle screw hardware loosening is the presence of a peri-implant lucency zone around the screw threads.

  • Computed tomography (CT) is used to detect peri-implant lucency (peri-implant lucency), which is a sign of screw loosening.
  • Radiography enables the evaluation of migration, loosening, and breakage of metal hardware.
  • Dynamic functional tests (flexion/extension) are used to assess mobility in the fusion zone and detect instability or pseudarthrosis.
  • Signs of late failure also include hardware fracture, implant migration, and progressive malalignment.
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What else to study on this topic

  • Intraoperative and Perioperative Complications
  • Early Complications of Spine Surgery
  • Late Complications and Hardware Failure
  • Imaging Modalities for the Postoperative Spine

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Other topics in the "Spine" section

Surgical Approaches to the SpinePedicle ScrewsSpinal Epidural HematomaPseudomeningocelePostoperative Spinal ChangesCT of the Lumbosacral Spine
Entire "Spine" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.