Treatment of Thoracic disk

herniationYoumans 283

Samer Ghostine, Srinath Samudrala,J. Patrick Johnson15/11/2559

Outline• Clinical presentation and differential diagnosis• Radiologic evaluation• Management• Result and complication

Clinical presentation

• Pain ; most common symptom• Sensory change in radicular pattern, sensory loss is rare• Spinal cord compression ; myelopathy, weakness and bowel and

bladder dysfunction• Spinal cord symdrome : Brown-Sequard syndrome, anterior spinal

artery syndrome, conus medullaris syndrome• Rare : Horner’s syndrome, dysesthesia in the medial arm

Differential diagnosis• Primary and metastasis neoplasm• Demyelinating disease• Primary motor neuron disease• Neuromuscular disease• Myopathy• Muscular dystrophy• Motor neuropathy• Spinal cord infarction• Spinal vascular malformation• Visceral pain : renal colic, gallbladder colic, colitis, intercostal neuritis, costochondritis

Radiologic evaluation

• MRI • noninvasive nature and high sensitivity• 14.5% false-positive rate : add clinical information• sagittal : edge effect between disc and CSF on T2• axial : level of stenosis, increased signal on T2 may be seen in the spinal cord• distinguish herniated disks in the thoracic spine from neoplastic,

demyelinating, or infectious pathologies• distinguish intradural versus extradural lesions

Radiologic evaluation• Myelography and Postmyelography Computed Tomography• it typically shows an indentation caused by an extradural mass compressing

the dural sac• postmyelography CT allows the distinction among bone, calcified soft tissue,

soft tissue, dural sac, and spinal cord• high false-positive rate (13.5%)

Radiologic evaluation• Radiography• alignment of the vertebral column to rule out a kyphotic or scoliotic deformity• the disk spaces for diskitis• the end plates for degenerative disk disease• the vertebrae for osteomyelitis• compression or burst fractures• osteolytic or osteoblastic lesions• suggest a calcified disk when the disk space is collapsed : highly suspicious of

a thoracic herniated disk

Management

Nonsurgical Management

• Restricted activity• Immobilization with a hyperextension brace• 0ral steroids• NSIAD• Oral pain medications• Epidural injections• Aim : allow the herniated disk to resorb and the inflamed nerve root

to heal

Indication for surgery• Refractory pain• Progressive myelopathy

Surgical Management

Posterior approach• Posterior thoracic laminectomy• because 70-90% central or paracentral : inadequate exposure of midline herniated disk • significant retraction of the dural sac

• Transpedicular approach• better exposure of the paracentral herniated disk• minimal dural sac retraction and sparing of the facet

Posterolateral approach• Costotransversectomy approach• the transverse process and a proximal piece of the rib head(5 cm lateral to)

are resected• providing further direct midline exposure of the ventral dura• Skin incision : curve paramedian skin incision, midline incision• Remove rib 5 to access T4-5 space

Posterolateral approach• Lateral extracavitary and lateral parascapular approaches• more lateral exposure and dissection than the costotransversectomy

approach• useful when an extensive exposure is required for the placement of cages or

the performance of vertebrectomy for infectious, neoplastic, or traumatic lesions• cutting the head of the rib as well as 8 cm of the rib distal to the dorsal root

ganglion• The intercostal nerve is sacrificed by tying it 3 cm distal to the dorsal root

ganglion

Posterolateral approach• Extrapleural approach to the anterior elements without the need for

postoperative chest tubes• Anterior or posterior instrumentation in the same setting if needed• Can be performed in a minimally invasive fashion by using the METRx tube

(Medtronic Sofamor Danek, Memphis, TN) and an endoscope• Not facet-sparing both

• Fusion should be considered for some patients, especially in the lower thoracic levels, where the rib cage does not provide as much support

Anterior approach• Central or paracentral herniated disks, especially if the disk is calcified and

intraspinal• Without the need to manipulate or retract the dura• At the T11-L1 region, the diaphragm limits the surgeon’s working channel and

must be retracted : retroperitoneal approach or thoracoscopic approach• Thoracoscopic approach : either side from T2 down to T12• Need thoracic surgeon• Anesthesia : double lumen tube• One rib is resect, above the disc space• Need for chest tube

possible conversion to open thoracotomy

Posterior axillary line Anterior axillary line

Result and complication• New-onset mild myelopathy : better chance for improvement or

recovery• It is hard to compare the results of the different approaches because

of the low incidence of thoracic disk herniation, the nonstandardized measurement of results, and some surgeons’ preference for one particular approach• Improvement • Myelopathy 70-90 %• Back and radicular pain 67-94 %

Result and complication• Misdiagnoses and misidentifications of surgical level• preoperative lumbar and thoracic plain films• CT of the thoracic spine• use of high-quality intraoperative fluoroscopy• intraoperative image-guided system

• Reopearate• misidentified• herniated disk was incompletely dissected

• inadequate visualization• calcified• midline