Surgery for thoracic disc herniations is still challenging, and the disc excision via a posterior laminectomy is considered risky. A variety of dorsolateral and ventral approaches have been developed. However, the lateral extracavitary and transthoracic approach require extensive surgical exposure. Therefore, we adopted a posterior transdural approach for direct visualization without entry into the thoracic cavity. Three cases that illustrate this procedure are reported here with the preoperative findings, radiological findings and surgical techniques used. After the laminectomy, at the involved level, the dorsal dura was opened with a longitudinal paramedian incision. The cerebrospinal fluid was drained to gain more operating space. After sectioning of the dentate ligaments, gentle retraction was applied to the spinal cord. Between the rootlets above and below, the ventral dural bulging was clearly observed. A small paramedian dural incision was made over the disc space and the protruded disc fragment was removed. Neurological symptoms were improved, and no surgery-related complication was encountered. The posterior transdural approach may offer an alternative surgical option for selected patients with thoracic paracentral soft discs, while limiting the morbidity associated with the exposure.

Objective

Burr hole drainage has been widely used to treat chronic subdural hematoma (CSDH). However, the incidence of recurrent CSDH varies from 3.7 to 30% after surgery. The authors attempted to elucidate the risk factors associated with the recurrence of CSDH in one burr hole drainage technique.

Methods

A total of 255 consecutive cases who underwent one burr hole drainage for CSDH were included in this study. Twenty-four patients (9.4%) underwent a repeated operation because of the recurrence of CSDH. We analyzed retrospectively the demographic, clinical and radiologic factors associated with the recurrence of CSDH.

Results

In this study, two risk factors were found to be independently associated with the recurrence of CSDH. The incidence of CSDH recurrence in the high- and mixed-density groups was significantly higher than those in the low- and iso-density groups (p<0.001). Bleeding tendency such as in leukemia, liver disease and chronic renal failure was also significantly associated with recurrence of CSDH (p=0.037).

Conclusion

These results suggest that high- and mixed- density shown on computed tomographic scan was closely relates with a high incidence of recurrence. Therefore, the operation could be delayed in those cases unless severe symptoms or signs are present. Reoperation using the previous burr hole site is a preferred modality to treat the recurrent CSDH.