Treatment Concept and Technical Considerations of Biportal Endoscopic Spine Surgery for Lumbar Spinal Stenosis

Decompression is a major component of surgical procedures for degenerative lumbar spinal stenosis (LSS). In addition to sufficient decompression to guarantee the relief of neurological pain, compensating surgical instability after wider laminectomy and foraminotomy and instrumentation with caging and fusion with grafting are performed to secure or restore the foraminal dimension and correct coronal/sagittal imbalance for longer survival of the adjacent segment. Endoscopic spinal surgery (ESS) has been developed under the flag of successful decompression while preserving structural integrity as much as possible with the help of magnification and illumination. ESS provides a technical possibility and feasibility for solving LSS by decompression alone. Recently, many endoscopic trials have been conducted to overcome conventional surgical treatment that requires wider dissection, escape inevitable complications from surgical damage, and compensate for the fusion technique. However, biportal ESS has some technical limitations, including clinical difficulties in accessibility for more moderate to severe stenosis and challenges for complicated conditions with segmental ventral slip, isthmic defect, stenosis combined with foraminal stenosis or foraminal disk rupture, or degenerative segmental scoliosis with disk height collapsing and endplate fatigue fracture. Because decompression alone is a skill for eliminating pathologies, there is no function of preserving degenerative structure or stopping the recurrence of disk degeneration or subsidence. This review of clinical reports investigated the possibility of biportal ESS for treating degenerative lumbar disorders by sufficient decompression and adequate elimination of various pathologies and decreasing technical complications. The results of this study may help develop better innovative spinal surgical techniques in the near future.

Mini-Transthoracic Supradiaphragmatic Approach to the Thoracolumbar Junction

Anterior reconstruction with instrumentation of the thoracolumbar junction (TLJ) offers: 1) the biomechanical advantage of immediate restoration of the load-bearing anterior column and 2) the ideal biological milieu for an optimal arthrodesis. The authors describe the mini-transthoracic supradiaphragmatic (MTTS) approach to the TLJ. Its technical feasibility is compared with that of the traditional transdiaphragmatic and thoracoscopic supradiaphragmatic approaches to this area of the spine. This technique was performed in 21 patients from 2004 to 2006. There were no surgical mortalities. The MTTS approach without the use of a thoracoscope was successfully employed in this study to treat patients with various lesions located at the TLJ. The diaphragmatic opening, even at its smallest diameter, provides excellent views of the operative field and avoids the significant morbidities associated with the traditional transdiaphragmatic approach.

Expandable Cage for Cervical Spine Reconstruction

OBJECTIVE: Expandable cage used for spinal reconstruction after corpectomy has several advantages over nonexpendable cages. Here we present our clinical experience with the use of this cage after anterior column corpectomy with an average of one year follow up. METHODS: Ten patients underwent expandable cage reconstruction of the anterior column after single-level or multilevel corpectomy for various cervical spinal disorders. Anterior plating with or without additional posterior instrumentation were performed in all patients. Functional outcomes, complications, and radiographic outcomes were determined. RESULTS: There was no cage-related complication. Functionally, neurological examination revealed improvement in 7 of 10 patients and no patient had neurological deterioration after the surgery. Immediate stability was achieved and maintained throughout the period of follow-up. There was minimal subsidence (<2mm) noticeable in three of the cases that underwent a two-level corpectomy. Subsidence was noted in osteoporotic patients and patients undergoing multi-level corpectomies. Average pre-operative kyphotic angle was 9 degrees. This was corrected to an average of 5.4 degrees in lordosis postoperatively. CONCLUSION: In conclusion, expandable cages are safe and effective devices for vertebral body replacement after cervical corpectomy when used in combination with anterior plating with or without additional posterior stabilization. The advantages of using expandable cages include its ability to easily accommodate itself into the corpectomy defect, its ability to tightly purchase into the endplates after expansion and thus minimizing the potential for migration, and finally, its ability to correct kyphosis deformity via its in vivo expansion properties.

A STDUY ON THE SURFACE MORPHOLOGY AND BOND STRENGTH OF DENTURE BASE RESIN TO COBALT-CHROMIUM ALLOY AFTER VARYING MODES OF SURFACE TREATMENT / 대한치과보철학회지

The purpose of this experiment was to determine the effects of various treatments on denture base resin to metal bond for cobalt-chromium alloy. The metal surface was treated as follows. Group 1 : Sandblasted with 50microneter aluminum oxide. Group 2 : Sandblasted with 250microneter aluminum oxide. Group 3 : Sandblasted with 250microneter aluminum oxide and followed by silicoating. Group 4 : Electrochemically etched. Group 5 : treated with oxidizing solution. Group 6 : Beaded with 200microneter retention structure and followed by silicoating. All specimens were applied with 4-META resin and were thermocycled 1000 times at temperature of 5degrees C to 55degrees C. The effects of various surface treatments on the bond strength between 4-META resin and metal interface were measured by using the universal testing machine. All specimens were observed with SEM. The results were as follows 1. The bond strength of 4-META resin were significantly higher to Co-Cr alloy. 2. The bond strength decreased in the following orders : group 6, group 3, groups 1 and 2, group 4, group 5 and there was no statistically significant difference in bond strength among groups 1 and 2. (p>0.05) 3. The bond strength of cobalt-chromium alloy to 4-META resin were not significantly different. (p>0.05) 4. The treated surface of groups 1, 2 and 3 has more fine undercut than that of groups 4 and 5 with SEM. 5. Stable adhesion can be achieved when mechanically roughened metal surface by sandblasting than treating in an electrochemical etching and an oxidizing solution with potassium manganate.