Circumspinal decompression and fusion through a posterior midline incision to treat central calcified thoracolumbar disc herniation: a minimal 2-year follow-up study with reconstruction CT.

PURPOSE

There have been several surgical approaches used in the treatment of thoracolumbar disc herniation (TLDH) from T10/11 to L1/2. However, central calcified TLDH cases are still challenging to spine surgeons. The anterior transthoracic approaches and lateral/posterolateral approaches are all essentially performed from one side; thus, the compressive lesion and the dura matter on the other side of the spinal canal are not clearly visualized, predisposing the procedure to incomplete decompression or inadvertent cord manipulation. Moreover, a number of these approaches are technically demanding and require entry into the chest. The purpose of this study was to introduce a new surgical procedure-circumspinal decompression and fusion through a posterior midline incision-for the treatment of central calcified TLDH and to evaluate its surgical outcome.

METHODS

In this study, 22 patients (15 males and 7 females; mean age 49 years) with central calcified TLDH underwent this procedure between April 2008 and April 2011. Altogether, 26 discs were excised, with two discs at T10/11, eight discs at T11/12, nine discs at T12/L1 and seven discs at L1/2. Of these patients, 16 returned for final follow-up, with a mean follow-up period of 41 months (range 24-57 months). Clinical outcomes, including operative time, blood loss, perioperative complications, post-operative time of hospitalization, neurological status improvement, extent of decompression, back pain, local spinal curvature and fusion, were investigated. The patients' neurological status was evaluated by a modified Japanese Orthopedic Association scoring system of 11 points. Fusion and the extent of decompression were evaluated by reconstruction CT at final follow-up.

RESULTS

The mean operative time was 185 min, the mean blood loss was 896 ml and the mean post-operative hospitalization time was 8 days. Four patients suffered perioperative complications, but only two were related to dura violation and none involved the respiratory system. All of the 16 patients who returned for the final follow-up showed improvement, and evidence of improvement was found in five of the other six patients who did not return for final follow-up through telephone interview or earlier follow-up evaluations. Complete decompression was achieved in 12 of the 16 patients who returned for final follow-up. In the 16 patients who returned for final follow-up, back pain was significantly reduced and local spinal curvature remained unaltered. In addition, based on reconstruction CT images, solid fusion was observed in 15 of the 16 patients who returned for final follow-up.

CONCLUSIONS

The circumspinal decompression and fusion through a posterior midline incision procedure can be used to treat central calcified TLDH patients with neurological deficits. This method's greatest advantage is that it is a highly effective and safe procedure for decompression. Although it is a major and destructive procedure, spinal stability was well maintained in most of the cases. In this era when minimally invasive spine surgeries like thoracoscopy have been in an upward trajectory, spine surgeons still should be made aware of this procedure.