Anterior or posterior approach of thoracic disc herniation? A comparative cohort of mini-transthoracic versus transpedicular discectomies.

BACKGROUND CONTEXT

The optimal surgical treatment of thoracic disc herniations remains controversial and depends on the consistency of the herniation and its location related to the spinal cord.

PURPOSE

To compare the outcomes of patients with symptomatic thoracic disc herniations treated with anterolateral mini-transthoracic approach (TTA) versus posterior transpedicular discectomy.

STUDY DESIGN

This is a prospective comparative cohort study.

PATIENT SAMPLE

One hundred consecutive patients with symptomatic thoracic herniated discs were operated by mini-TTA (56 patients) or transpedicular discectomy (44 patients).

OUTCOME MEASURES

Neurologic assessment by American Spinal Injury Association (ASIA) Impairment Scale and patients' self reported perceived recovery and complications.

METHODS

The consistency and location of the herniated disc in relation to the spinal cord was evaluated by preoperative computed tomography and magnetic resonance imaging. Patients were assessed neurologically before surgery and at regular outpatient controls at 2 months or later. Long-term follow-up was achieved by questionnaires sent by mail.

RESULTS

In both groups, most patients had symptoms of myelopathy and radicular pain; patients who underwent mini-TTA, more frequently suffered from spasticity. Fifty-eight percent of the herniated discs were calcified and 77% were larger than one-third of the spinal canal. All patients presented with ASIA Grade C or D (64%) or ASIA Grade E (36%). Postoperatively, 50% of the patients treated with mini-TTA and 37% of the transpedicular group improved at least one grade on the ASIA scale (p=.19). The duration of surgery, blood loss, hospital stay, and complication rate were significantly higher in patients treated with mini-TTA and were mainly related to the magnitude and consistency of the herniated disc. At long-term follow-up, 72% of the mini-TTA patients reported good outcome versus 76% of the transpedicular discectomy group (p=.80).

CONCLUSIONS

Surgical treatment of a symptomatic herniated disc contributed to a clinical improvement in most cases. The approach is dependent on the location, the magnitude, and the consistency of the herniated thoracic disc. Medially located large calcified discs should be operated through an anterolateral approach, whereas noncalcified or lateral herniated discs can be treated from a posterior approach as well. For optimal treatment of this rare entity, the treatment should be performed in selected centers.