Minimally Invasive Lumbar Decompression, Interbody Fusion, and Pedicle Screw Fixation: Preliminary Report

OBJECTIVE: With improvement in endoscopic visualization and surgical tools, several minimally invasive procedures such as transpedicular fixation, interbody fusion, or decompression have advocated their respective advantages. But all these procedures are developed separately and are not related to other techniques. The authors utilize these procedures as organized procedure like comprehensive conventional procedure. This study is designed to study early results of minimally invasive decompression, interbody fusion, and endoscopic pedicle screw fixation. METHODS: We utilized minimally invasive decompression, interbody fusion, and endoscopic pedicle screw fixation on 12 consecutive patients(9 female, 3 male, mean age 54.8 years). For decompression, unilateral laminectomy and controlateral laminar undercutting was performed through tubular retractor, and interbody fusion(PLIF or TLIF) was done with one cage and bone packing. Pedicle screw fixation was done using expandable tubular retractor under endoscopic visualization and fluoroscopic guidance. Contralateral screw fixation was done with the same manner. RESULTS: There were five spinal stenosis and seven degenerative spondylolisthesis. All patients received one level (L4-5) decompression, interbody fusion, and fixation. Mean operating time was 245.8 minutes. There was dural tear in one patient. All patients were excellent or good with average follow up of 7.2 months. Bone fusion was not evident due to short-term follow-up, but there were no instability or screw loosening. CONCLUSION: Although it is small series and has short-term follow-up, this study demonstrates that minimally invasive decompression, interbody fusion, and pedicle screw fixation are feasible and effective.

Transcranial Doppler Examination Following EIAB in Patients with Hemodynamic Cerebral Ischemia

OBJECTIVE: The aim of this study is to evaluate the effects of intracranial-extracranial arterial bypass(EIAB) surgery on cerebrovascular reserve capacity(CRC) in patients with hemodynamic cerebral ischemia and to assess the significance of transcranial doppler(TCD) examination before and after EIAB surgery. METHODS: In 29 consecutive patients who underwent EIAB surgery due to symptomatic internal carotid artery or middle cerebral artery(MCA) occlusion, 21 patients were studied using preoperative and postoperative digital subtraction angiogram(DSA), SPECT, and TCD examination. After measuring mean radioactivity count of a region of interest, relative regional cerebral blood flow(rrCBF) was quantitated by the following formula: lesional radioactivity count/contralateral radioactivity count x 100%. CRC was calculated as the percentage change from baseline flow after a vasodilatory challenge. RESULTS: Postoperative DSA showed good collateral circulation through the bypass except 4 patients. Preoperative mean value of rCRC improved significantly after EIAB surgery from -14.8+/-2.6% to 6.9+/-2.7%(p<0.01). Intraoperatively, flow velocity of superficial temporal artery(STA) and MCA just after anastomoses increased remarkably in comparison with the values just before anastomoses(p<0.01). There was no correlation between the change of pre- and postoperative flow velocity and the change of rrCBF. In patients with the increase of flow velocity after surgery manifested good collateral circulation through the bypass. The difference was statistically significant(repeated measures ANOVA, p<0.05). Over a mean follow-up period of almost 3 years, no patient had another episode of brain ischemia. CONCLUSION: We believe that the measurement of flow velocity is expected a good method to evaluate the degree of collateral circulation through the bypass.

A Pitfall in the Use of Three Dimensional Computed Tomographic Angiography for Early Surgery of Ruptured Cerebral Aneurysm: Case Report

Three dimensional computed tomographic angiography is a rapid and minimally invasive method of detecting intracranial aneurysms, however, there are some limitation to identify the associated cerebrovascular lesions. We report a case of ruptured dorsal wall aneurysm of internal carotid artery in a 50-year-old man who had underlying stenosis of cervical internal carotid artery, which was overlooked due to lesion outside the scan field of view.