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Thoracic disc herniation


Introduction

Thoracic disc herniations (TDHs) are commonly found on imaging and occur in up to 37% of asymptomatic individuals. A large proportion of TDHs are giant (occupying >40% of the spinal canal) and calcified with tendencies to adhere and erode through the dura and cause progressive neurological decline requiring surgical treatment. There is no established gold standard treatment. Thoracic discectomies are challenging and historically have been associated with poor surgical outcomes and high neurological morbidity.

In this chapter we utilize a case example to illustrate the clinical presentation and surgical management of a giant calcified TDH.

Case Example

  • Chief complaint: back pain and lower extremity pain and weakness

  • History of present illness: The patient is a 74-year-old male with history of severe low thoracic back pain radiating to above his umbilicus and progressive lower extremity weakness. He also reports difficulty ambulating over the past month. Thoracic spine imaging ( Figs. 8.1 and 8.2 ) revealed a sizable T9–10 calcified thoracic disc compressing and displacing the spinal cord to the left.

    Fig. 8.1, Preoperative axial (A) and sagittal (B) computed tomography bone windows showing a sizable calcified thoracic disc herniation occupying more than 40% of the anteroposterior spinal canal. Note that the nucleus pulposus is also abnormally calcified.

    Fig. 8.2, Preoperative sagittal (A) and axial (B) thoracic spine MRI redemonstrating this giant herniated thoracic disc causing spinal cord compression (note the high T2 signal within the spinal cord cranial to the disc) (A) and displacing the spinal cord to the left (B).

  • Medications: diuretics, ASA 325 mg

  • Allergies: no known drug allergies

  • Past medical history: congestive heart failure and coronary artery disease

  • Past surgical history: none

  • Family history: none

  • Social history: none

  • Physical examination: awake, alert, and oriented to person, place, and time; cranial nerves II–XII intact, full strength in the upper extremities: bilateral deltoids/triceps/biceps/grip/interossei 5/5; weak lower extremities: hip flexors 3/5, knee extensors 3/5, ankle dorsiflexion 4/5, long toe extensor and ankle plantar flexion 5/5.

  • Reflexes: 2+ response in bilateral biceps/triceps/brachioradialis with negative Hoffman and lower extremity hyperreflexia and clonus with 3+ response in bilateral patella and Achilles tendons; abnormal lower extremity light touch and proprioception with T10 sensory level

  • Laboratories: all within normal limits

  • Jorge Eduardo Guzman Prenk, MD

  • Neurosurgery

  • Pontifica Universidad Javeriana

  • Bogota, Colombia

  • Langston Holly, MD

  • Neurosurgery

  • University of California at Los Angeles

  • Los Angeles, California, United States

  • Sutipat Pairojboriboon, MD

  • Orthopaedic Surgery

  • Vichaiyut Hospital

  • Phyathai, Thailand

  • Frank M. Phillips, MD

  • Orthopaedic Surgery

  • Rush University

  • Chicago, Illinois, United States

Preoperative
Additional tests requested

  • MRI T-spine

  • SSEP/MEP

  • MRI T-spine

  • T-spine AP and lateral x-rays

  • Medicine evaluation

  • MRI T-spine

  • Angiogram

  • Cardiology evaluation

  • Anesthesia evaluation

  • MRI T-spine

  • Standing x-rays

Surgical approach selected T9–10 MIS laminectomy, foraminotomy T9–10 transpedicular costotransversectomy for partial corpectomy and discectomy, laminectomy, right facetectomy T9–10 costotransversectomy discectomy, posterolateral T7-L1 fusion T9–10 laminectomy, transpedicular discectomy, and fusion
Goal of surgery Decompress spinal cord Decompress spinal cord Decompress spinal cord, neurological preservation Decompress spinal cord
Perioperative
Positioning Left lateral decubitus Prone on Jackson table Prone on Jackson table Prone
Surgical equipmentSurgical microscope Hi Speed Drill With diamond tip burrs

  • Fluoroscopy

  • IOM (MEP/SSEP)

  • Tubular retractor

  • IOM (MEP/SSEP)

  • Fluoroscopy

  • Surgical microscope

  • Surgical navigation

  • Fluoroscopy

  • IOM (MEP/SSEP/EMG)

  • Ultrasonic bone scalpel

  • Surgical microscope

  • Ultrasound

  • Fluoroscopy

  • IOM

Medications None None Steroids, MAPs >80 Maintain MAP
Anatomical considerations Pedicles, facets, dura, nerve root Spinal cord, nerve roots, segmental artery Artery of Adamkiewicz, segmental artery, spinal cord Spinal cord
Complications feared with approach chosen Instability CSF leak, spinal cord injury, hardware-related problems Ventral dural tear, arterial injury, inadequate discectomy Neural injury, CSF leak
Intraoperative
Anesthesia General General General General
Exposure T9–10 T9–10 T7-L1 T9–10
Levels decompressed T9–10 T9–10 T9–10 T9–10
Levels fused None None T7-L1 T9–10
Surgical narrative Position left lateral decubitus, fluoroscopy in AP projection to identify right T9–10 facet and ipsilateral pedicle, right paramedian incision, sequentially place tubes using Seldinger technique with entry point on the superior lateral quadrant of the pedicle, place and fix tubular system, drill T9 right lamina and partial right inferior facet and T10 right superior facet, right T9–10 foraminotomy, drill calcified disc in lateral to medial and inside-out manner if possible, send samples to pathology, withdraw tubular system once hemostasis confirmed, layered closure Position prone on Jackson table, localize incision using AP fluoroscopy, midline posterior incision, T9–10 laminectomy, right facetectomy, place reference frame, O-arm spin, register with navigation, potentially remove rib head if needed to increase working angle, perform partial transpedicular corpectomy to create space to displace disc away from cord, sacrifice nerve root, incise disc herniation and remove, palpate to confirm decompression, additional O-arm to confirm decompression, layered closure with drain Position prone on Jackson table, count spinal levels and ribs or pre and intraoperative x-rays, midline skin incision, expose lamina and transverse process, T9–10 laminectomy, remove right facet/transverse process/ribs using ultrasonic bone scalpel or drill, rib removal with care to avoid tearing underlying pleura, identify and follow right T10 nerve root medially to foramen, suture and ligate nerve root, use nerve root for gentle traction, drill down right pedicle, discectomy under surgical microscope, incise PLL and disc annulus, clear disc space with curettes and drill if necessary, send specimen to pathology, separate ventral thecal sac from calcified disc and push disc ventrally into working cavity, ultrasound to evaluate disc morphology and adequacy of decompression, pedicle screw placement three levels above and below and left pedicle at index level, intraoperative O-arm to assess instrumentation, connect rods, local and allograft bone grafts in posterolateral gutters, antibiotic irrigation and vancomycin powder, standard closure with drains Position prone, laminectomy above and below index level, wide laminectomy at index level without instrument intrusion into spinal canal, resect facet and pedicle as needed adjacent to calcified intracanal material, approach calcified material from far lateral, thin calcified material with drill from inside-out creating thin shell of material adjacent to cord, collapse remaining bony shell away from cord with micro and reverse angle curettes, instrument and fuse level destabilized by wide decompression and facetectomy, layered closure
Complication avoidance AP fluoroscopy to identify level, minimally invasive approach, drill in lateral to medial and inside-out manner to avoid dural injury AP fluoroscopy to identify surgical level, potentially remove rib head to increase working angle, surgical navigation, partial corpectomy to displace disc away from cord, sacrifice nerve root, O-arm spin to confirm decompression Count levels based on spinal level and ribs, costotransversectomy with care to protect pleura, suture and ligate T10 nerve root, use nerve root for gentle traction, removal of T10 pedicle, separate disc from thecal sac, ultrasound to assess disc and decompression, intraoperative O-arm to assess instrumentation Resect pedicle as need adjacent to calcified intracanal material, approach calcified material from far lateral, eggshell calcified material, remove remaining bone away from cord
Postoperative
Admission Outpatient Floor ICU Floor
Postoperative complications feared CSF leak, epidural hematoma, wound infection Neurological deficit, CSF leak, spinal instability Inadequate decompression, intercostal neuralgia, dural tear Neural injury, CSF leak
Anticipated length of stay Same day 3 days 4–5 days 2–3 days
Follow-up testing

  • CT T-spine 4 months after surgery

  • MEP/SSEP 4 months after surgery if results unsatisfactory

None T–L spine x-rays at each follow-up visit T–L spine x-rays 6 weeks, 3 months, 6 months, 1 year after surgery
Bracing None None None None
Follow-up visits 10 days, 4 months after surgery 2 weeks, 6 weeks, 3 months, 6 months, 1 year after surgery 2 weeks, every 3 months until 1 year after surgery 2 weeks, 6 weeks, 3 months, 6 months, 1 year after surgery
AP , Anteroposterior; CSF , cerebrospinal fluid; CT , computed tomography; EMG , electromyography; ICU , intensive care unit; IOM , intraoperative monitoring; MAP , mean arterial pressure; MEP , motor evoked potential; MRI , magnetic resonance imaging; PLL , posterior longitudinal ligament; SSEP , somatosensory evoked potential.

Differential diagnosis

  • ▪

    Metastasis

  • ▪

    Tuberculosis

  • ▪

    Fungal infection

  • ▪

    Thoracic stenosis

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