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.

Risk Factors and Options of Management for an Incidental Dural Tear in Biportal Endoscopic Spine Surgery

Methods@#We have retrospectively studied IDTs by four surgeons during 1 or 2 years after starting BESS for lumbar degenerative diseases and analyzed the locations, sizes, and specific endoscopic conditions specific to each. @*Results@#Twenty-five cases (1.6%) of IDTs among 1,551 cases of BESS occurred; 13 cases (52%) of these were within the first 6 months. The locations were dorsal midline in 12 cases, ipsilateral side in 11 cases, and contralateral side in two cases. The tear sizes were <10 mm in 20 cases and ≥10 mm in five cases. IDT commonly occurred due to injury of central dural folding during flavectomy under turbid surgical fields due to small bleeds under water. Twenty cases with IDTs of <10 mm were treated well with the patch technique. Among five cases of ≥10 mm, three underwent open repair within a few days, and two of these which failed to conservative management required a delayed revision operation due to pseudomeningocele. No cases progressed to surgical site infection or infectious spondylitis. @*Conclusions@#IDTs of <10 mm can be successfully treated with the patch technique. To prevent IDT during the early learning period, maintaining clear visibility by securing fluent saline outflow and meticulous hemostasis of small bleeding from exposed cancellous bone and epidural vessels is essential with caution not to injure the central dural folding during midline flavectomy.

Risk Factors and Options of Management for an Incidental Dural Tear in Biportal Endoscopic Spine Surgery

Methods@#We have retrospectively studied IDTs by four surgeons during 1 or 2 years after starting BESS for lumbar degenerative diseases and analyzed the locations, sizes, and specific endoscopic conditions specific to each. @*Results@#Twenty-five cases (1.6%) of IDTs among 1,551 cases of BESS occurred; 13 cases (52%) of these were within the first 6 months. The locations were dorsal midline in 12 cases, ipsilateral side in 11 cases, and contralateral side in two cases. The tear sizes were <10 mm in 20 cases and ≥10 mm in five cases. IDT commonly occurred due to injury of central dural folding during flavectomy under turbid surgical fields due to small bleeds under water. Twenty cases with IDTs of <10 mm were treated well with the patch technique. Among five cases of ≥10 mm, three underwent open repair within a few days, and two of these which failed to conservative management required a delayed revision operation due to pseudomeningocele. No cases progressed to surgical site infection or infectious spondylitis. @*Conclusions@#IDTs of <10 mm can be successfully treated with the patch technique. To prevent IDT during the early learning period, maintaining clear visibility by securing fluent saline outflow and meticulous hemostasis of small bleeding from exposed cancellous bone and epidural vessels is essential with caution not to injure the central dural folding during midline flavectomy.

Efficacy of Biportal Endoscopic Spine Surgery for Lumbar Spinal Stenosis

BACKGROUND: Biportal endoscopic spine surgery (BESS) is a recent addition to minimally invasive spine surgery treatments. It boasts excellent magnification and fine discrimination of neural structures. Selective decompression with preservation of facet joints for structural stability is also feasible owing to access to the spinal canal and foramen deeper inside. This study has a purpose to investigate clinical benefits of BESS for spinal stenosis in comparison to the other common surgical treatments such as microscopic decompression-only (DO) and fusion and instrumentation (FI). METHODS: From December 2013 to March 2015, 30 cases of DO, 48 cases of FI, and 66 consecutive cases of BESS for lumbar spinal stenosis (LSS) were enrolled to evaluate the relative clinical efficacy of BESS. Visual analog scale (VAS) for back pain and leg pain, postoperative hemoglobin, C-reactive protein (CRP) changes, transfusion, and postoperative complications were examined. RESULTS: All the patients were followed up until 6 months, and 98 patients (86.7%) for 2 years. At the 6-month follow-up, VAS for back pain improved from 6.8 to 2.8, 6.8 to 3.2, and 6.8 to 2.8 (p = 0.078) for BESS, DO, and FI, respectively; VAS for leg pain improved from 6.3 to 2.2, 7.0 to 2.5, and 7.2 to 2.5 (p = 0.291), respectively. Two cases in the BESS group underwent additional foraminal decompression, but no fusion surgery was performed. Postoperative hemoglobin changes for BESS, DO, and FI were −2.5, −2.4, and −1.3 mL, respectively. The BESS group had no transfusion cases, whereas 10 cases (33.3%) in DO and 41 cases (85.4%) in FI had transfusion (p = 0.000). CRP changes for BESS, DO, and FI were 0.32, 6.53, and 6.00, respectively, at day 2 postoperatively (p = 0.000); the complication rate for each group was 8.6% (two dural tears and one root injury), 6.7% (two dural tears), and 8.3% (two dural tears and two wound infections), respectively. CONCLUSIONS: BESS for LSS showed clinical results not inferior to those of the other open surgery methods in the short-term. Stable hemodynamic changes with no need for blood transfusion and minimal changes in CRP were thought to cause less injury to the back muscles with minimal bleeding. Foraminal stenosis decompression should be simultaneously conducted with central decompression to avoid an additional surgery.

Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis

Biportal endoscopic spinal surgery (BESS) is a minimally invasive spinal surgery, which is basically similar to microscopic spinal surgery in terms of the use of floating technique and technically similar to conventional percutaneous endoscopic spinal surgery in terms of the use of endoscopic or arthroscopic instruments. Using two independent portals (viewing and working) and maintaining a certain distance from the bony and neural structures allow closer access to the target lesion through a panoramic view by free handling of the scope and instruments rather than through a fixed view by docking into the Kambin's triangle. Minimally invasive surgery allows for reduced dissection and inevitable muscle injury, preserving stability and reducing risks of restabilization. The purpose of fusion surgery is the same as that of the three surgical techniques stated above. Its wider range of view helps to overcome limitations of conventional endoscopic spinal surgery and to supplement the weak points of microscopic spinal surgery, such as limited working space in a tubular retractor and difficulty in accessing the contralateral area. This technique provides an alternative to unilateral or bilateral decompression of lumbar central spinal stenosis, foraminal stenosis, low-grade spondylolisthesis, and adjacent segment degeneration. Early clinical outcomes are promising despite potential for complications, such as dural tearing and postoperative epidural hematoma, similar to other procedures. Merits of BESS include decreased postoperative infection rate due to continuous irrigation throughout the procedure and decreased need for fusion surgery for one- or two-level lumbar stenosis by wide sublaminar and foraminal decompression with minimal sacrifice of stabilizing structures.

Biportal Endoscopic Spinal Surgery for Lumbar Intervertebral Disc Herniation / 대한정형외과학회잡지

Herniation of the intervertebral disc is a medical disease manifesting as a bulging out of the nucleus pulposus or annulus fibrosis beyond the normal position. Most lumbar disc herniation cases have a favorable natural course. On the other hand, surgical intervention is reserved for patients with severe neurological symptoms or signs, progressive neurological symptoms, cauda equina syndrome, and those who are non-responsive to conservative treatment. Numerous surgical methods have been introduced, ranging from conventional open, microscope assisted, tubular retractor assisted, and endoscopic surgery. Among them, microscopic discectomy is currently the standard method. Biportal endoscopic spinal surgery (BESS) has several merits over other surgical techniques, including separate and free handling of endoscopy and surgical instruments, wide view of the surgical field with small skin incisions, absence of the procedure of removing fog from the endoscope, and lower infection rate by continuous saline irrigation. In addition, existing arthroscopic instruments for the extremities and conventional spinal instruments can be used for this technique and surgery for recurred disc herniation is applicable because delicate surgical procedures are performed under a brightness of 2,700 to 6,700 lux and a magnification of 28 to 35 times. Therefore, due to such advantages, BESS is a novel technique for the surgical treatment of lumbar disc herniation.

Biportal Endoscopic Spine Surgery for Various Foraminal Lesions at the Lumbosacral Lesion

The stenosing foramen of L5–S1 by several degenerative diseases is one of the challenging areas on surgical approaching because of the deeper depth and steep slope in the lumbosacral junction. The floating view using unilateral biportal endoscopic spine surgery rather than docking into the Kambin’s zone can make the foraminal structures seen panoramically and permit dynamic handling of various instruments without destroying the facet joint and causing iatrogenic instability. Fine discrimination of structural margins in helps of the higher magnification and gentle manipulation of neural structures just as in open spine surgery could be guaranteed using floating technique from the target structures. Selective decompression with preserving innocent structures including facet joints could relieve foraminal lesions at the L5–S1 and decrease the necessity of fusion surgery caused by wider decompression and iatrogenic instability.

Clinical and Radiological Outcomes of Foraminal Decompression Using Unilateral Biportal Endoscopic Spine Surgery for Lumbar Foraminal Stenosis

BACKGROUND: Since open Wiltse approach allows limited visualization for foraminal stenosis leading to an incomplete decompression, we report the short-term clinical and radiological results of unilateral biportal endoscopic foraminal decompression using 0° or 30° endoscopy with better visualization. METHODS: We examined 31 patients that underwent surgery for neurological symptoms due to lumbar foraminal stenosis which was refractory to 6 weeks of conservative treatment. All 31 patients underwent unilateral biportal endoscopic far-lateral decompression (UBEFLD). One portal was used for viewing purpose, and the other was for surgical instruments. Unilateral foraminotomy was performed under guidance of 0° or 30° endoscopy. Clinical outcomes were analyzed using the modified Macnab criteria, Oswestry disability index, and visual analogue scale. Plain radiographs obtained preoperatively and 1 year postoperatively were compared to analyze the intervertebral angle (IVA), dynamic IVA, percentage of slip, dynamic percentage of slip (gap between the percentage of slip on flexion and extension views), slip angle, disc height index (DHI), and foraminal height index (FHI). RESULTS: The IVA significantly increased from 6.24°± 4.27° to 6.96°± 3.58° at 1 year postoperatively (p = 0.306). The dynamic IVA slightly decreased from 6.27°± 3.12° to 6.04°± 2.41°, but the difference was not statistically significant (p = 0.375). The percentage of slip was 3.41% ± 5.24% preoperatively and 6.01% ± 1.43% at 1-year follow-up (p = 0.227), showing no significant difference. The preoperative dynamic percentage of slip was 2.90% ± 3.37%; at 1 year postoperatively, it was 3.13% ± 4.11% (p = 0.720), showing no significant difference. The DHI changed from 34.78% ± 9.54% preoperatively to 35.05% ± 8.83% postoperatively, which was not statistically significant (p = 0.837). In addition, the FHI slightly decreased from 55.15% ± 9.45% preoperatively to 54.56% ± 9.86% postoperatively, but the results were not statistically significant (p = 0.705). CONCLUSIONS: UBEFLD using endoscopy showed a satisfactory clinical outcome after 1-year follow-up and did not induce postoperative segmental spinal instability. It could be a feasible alternative to conventional open decompression or fusion surgery for lumbar foraminal stenosis.

Unilateral Biportal Endoscopic Spinal Surgery Using a 30° Arthroscope for L5–S1 Foraminal Decompression

Foraminal decompression using a minimally invasive technique to preserve facet joint stability and function without fusion reportedly improves the radicular symptoms in approximately 80% of patients and is considered one of the good surgical treatment choices for lumbar foraminal or extraforaminal stenosis. However, proper decompression was not possible because of the inability to access the foramen at the L5–S1 level due to prominence of the iliac crest. To overcome this challenge, endoscopy-based minimally invasive spine surgery has recently gained attention. Here, we report the technical skills required in unilateral extraforaminal biportal endoscopic spinal surgery using a 30° arthroscope to enable foraminal decompression at the L5–S1 level. Two 0.8-cm portals were created 2 cm lateral from the lateral border of the pedicles at the L5–S1 level. After sufficient working space was made, half of the superior articular process (SAP) in the hypertrophied facet joint was removed using a high-speed burr and a 5-mm wide osteotome, whereas the remaining inside part of the SAP was removed using a Kerrison punch and pituitary punch. The foraminal ligamentum flavum should be removed to inspect the conditions of the L5 exiting root and disc. Removing of the extruded disc could decompress the L5 root. The extraforaminal approach using a 30° arthroscope is considered a minimally invasive alternative technique for decompressing foraminal stenosis at the L5–S1 level that preserves facet stability and provides symptomatic relief.

Biportal Endoscopic Transforaminal Lumbar Interbody Fusion with Arthroscopy

Lumbar spine fusion has been widely accepted as a treatment for various spinal pathologies, including the degenerative spinal diseases. Transforaminal interbody fusion (TLIF) using minimally invasive surgery (MIS-TLIF) is well-known for reducing muscle damage. However, the need to use a tubular retractor during MIS-TLIF may contribute to some limitations of instrument handling, and a great deal of difficulty in confirming contralateral decompression and accurate endplate preparation. Several studies in spinal surgery have reported the use of the unilateral biportal endoscopic spinal surgery (technique for decompression or discectomy). The purpose of this study is to describe the process of and technical tips for TLIF using the biportal endoscopic spinal surgery technique. Biportal endoscopic TLIF is similar to MIS-TLIF except that there is no need for a tubular retractor. It is supposed to be another option for alternating open lumbar fusion and MIS fusion in degenerative lumbar disease that needs fusion surgery.

Clinical and Radiological Outcomes of Unilateral Biportal Endoscopic Decompression by 30° Arthroscopy in Lumbar Spinal Stenosis: Minimum 2-Year Follow-up

BACKGROUND: Open microscopic laminectomy has been the standard surgical method for degenerative spinal stenosis without instability till now. However, it is associated with complications such as paraspinal muscle injury, excessive bleeding, and wound infection. Several surgical techniques, including microendoscopic decompression, have been introduced to solve these problems. METHODS: Authors analyzed retrospectively 55 patients presenting with neurological symptoms due to degenerative lumbar spinal stenosis refractory to conservative treatment. Patients with foraminal stenosis requiring foraminal decompression were excluded. Two or three portals were used for each level. One portal was used for viewing purpose and the others for instrument passage. Unilateral laminotomy was followed by bilateral decompression under the view of 30° arthroscopy. Clinical outcomes were evaluated using modified Macnab criteria, Oswestry disability index (ODI), and visual analogue scale (VAS). Postoperative complications were checked during the 2-year follow-up. Plain radiographs before and after surgery were compared to analyze the change of disc height decrement and alignment. RESULTS: ODI scores improved from 67.4 ± 11.5 preoperatively to 19.3 ± 12.1 at 2-year follow-up (p < 0.01). VAS scores of the leg decreased from 7.7 ± 1.5 to 1.7 ± 1.5 at the final follow-up (p < 0.01). Per the modified Macnab criteria, 81% of the patients improved to good/excellent. No cases of infection occurred. The intervertebral angle was significantly reduced from 6.26°± 3.54° to 5.58°± 3.23° at 2 years postoperatively (p = 0.027) and the dynamic intervertebral angle changed from 6.54°± 3.71° to 6.76°± 3.59°, which was not statistically significant (p = 0.562). No significant change in slippage was observed (3.76% ± 5.01% preoperatively vs. 3.81% ± 5.28% at the final follow-up [p = 0.531]). The dynamic percentage slip did not change significantly, from 2.65% ± 3.37% to 2.76% ± 3.71% (p = 0.985). However, intervertebral distance decreased significantly from 10.43 ± 2.23 mm to 10.0 ± 2.24 mm (p = 0.000). CONCLUSIONS: Full endoscopic decompression using a 30° arthroscopy demonstrated a satisfactory clinical outcome at the 2-year follow-up. This technique reduces wound infection rate and did not bring about postoperative segmental spinal instability. It could be a feasible alternative to conventional open microscopic decompression or fusion surgery for degenerative lumbar spinal stenosis.

Biportal Endoscopic Spinal Surgery for Recurrent Lumbar Disc Herniations

The major problems of revision surgery for recurrent lumbar disc herniation (LDH) include limited visualization due to adhesion of scar tissue, restricted handling of neural structures in insufficient visual field, and consequent higher risk of a dura tear and nerve root injury. Therefore, clear differentiation of neural structures from scar tissue and adhesiolysis performed while preserving stability of the remnant facet joint would lower the risk of complications and unnecessary fusion surgery. Biportal endoscopic spine surgery has several merits including sufficient magnification with panoramic view under very high illumination and free handling of instruments normally impossible in open spine surgery. It is supposed to be a highly recommendable alternative technique that is safer and less destructive than the other surgical options for recurrent LDH.

Learning Curve Associated with Complications in Biportal Endoscopic Spinal Surgery: Challenges and Strategies

STUDY DESIGN: Descriptions of technical strategies to overcome pitfalls associated with early learning periods in biportal endoscopic spinal surgery (BESS). PURPOSE: To introduce BESS for lumbar spinal diseases (LSDs) and to inform certain challenges to be overcome in mastering the technique. OVERVIEW OF LITERATURE: BESS has shown superior benefits including excellent magnification, a wider range of view by dynamic handling of an endoscope and instruments. Clinical reports, however, have not yet been very revealing for its new introduction into minimally invasive spine surgery. METHODS: To evaluate the learning curve for BESS, the procedures for various LSDs by one surgeon were analyzed in the view of shortening of the operating times and reduction of complications. Reviewing of recorded procedures helped in finding the reasons and the implemented solutions. RESULTS: The 68 cases included 25 for lumbar disc herniation (LDH), 3 for revision for recurred LDH, 39 for lumbar spinal stenosis (LSS) and 1 for synovial cyst. The operation time for the total cases averaged 83.7±33.6 minutes. According to diagnosis, it was 68.2±23.7 minutes for LDH. After the 14th case of LDH, it was nearly constant and close to the average time. One level of LSS needed 110.4±34.4 minutes. Prolonged operation times even in some later cases of LSS were mainly from struggling against blurred vision due to epidural bleeding. There were 7 cases of complications (10.3%) including 2 cases of dural tear, 1 case of root injury, and 4 cases of incomplete decompression on postoperative magnetic resonance imaging. There was no case of symptomatic hematoma or wound infection. CONCLUSIONS: BESS seemed to have a relatively short learning curve period. The overall complication rate in early learning period was 10.3%. These could be avoided by magnified regional views on an endoscope and a clear surgical field by controlling epidural bleeding.

Awareness Assessment on Continuing Medical Education in Korean Orthopaedic Society / 대한정형외과학회잡지

PURPOSE: Awareness on continuing medical education (CME) of the Korean Orthopaedic Association (KOA) was investigated in order to augment the weak educational points of the conventional academic CME. MATERIALS AND METHODS: The web-survey was conducted in the KOA on the awareness of conventional academic or web-based CME. The questionnaire included working conditions, intimacy of informational technology, and strengths and weaknesses of academic and web-based CME. RESULTS: Among 3,427 emails sent, 168 (4.9% of effective response rate) responses were received. Of the responders, 74.4% of the responders could not attend CME frequently because of working time (35.7%) and a distance far from the working place (13.2%). The merits of academic CME included as the opportunity for considerations of other members' thoughts on some clinical matters (64.3%); however, the weak points were holding several similar conferences (60.1%) and too short time for adequate study (53.0%). They wanted that surgical procedures and tips (49.0%) to be provided in the form of lecture slides (44.6%) or movie clips (37.6%) in web-based CME. 95.5% of the responders showed positive response regarding the need for web-based CME. CONCLUSION: Results of the survey showed high needs and interests in web-based CME, which could support the weaknesses of the academic CME with less time for education and limited accessibility to CME due to time or space barriers due to their working conditions.

Web-Based Continuing Medical Education in Korean and Foreign Orthopaedic Societies / 대한정형외과학회잡지

PURPOSE: The current states of web-contents for continuing medical education (CME) of domestic and foreign orthropaedic web sites were investigated. MATERIALS AND METHODS: Korean Orthopaedic Association (KOA) and Korean Orthopaedic Cyber-Society (KOC) as domestic, and American Academy of Orthopaedic Surgerns (AAOS), Journal of Bone and Joint Surgery (JBJS), AOSpine, and Arthroscopy as foreign web sites were searched in view of provided information technology (IT), including electrical paper (ePDF), lecture and surgical procedure video clips, case discussion, interactive content, and CME credit program. RESULTS: KOA supplied 19 types of ePDFs, and KOC, 43 video clips, and 217 case discussions. However, only one video clip was updated from 2011 to 2012 and 20 video clips from 2008 were not accessible. AAOS provided one type of ePDF, 142 lecture and 570 surgical procedure video clips, five interactive CME programs and 107 CME credit programs. In JBJS, one kind of ePDF, 97 video clips, 24 case discussions, and 37 CME credit programs were provided. In AOSpine, 12 types of ePDFs, 994 video clips, one interactive content, and 347 case discussions were provided. In Arthroscopy, one type of ePDF and 126 video clips were supplied. All web-contents were available. CONCLUSION: A large number of better quality web-contents and web-based CME credit programs should be implemented with standardized IT for Web-based CME in domestic orthropaedic societies.

The Oblique Proximal Interlocking Screw for Intramedullary Nailing Proximal Tibial Fractures: Is It Safe? / 대한정형외과학회잡지

PURPOSE: We tried to reveal radiographic clues for the possibility of damages to the important structures, including the peroneal nerve and the anterior tibial artery, caused by a proximal interlocking screw with a medial to lateral oblique direction (ObML-PIS). MATERIALS AND METHODS: The length of the proximal tibiofiular joint (PTFJ) was measured from the tip of the fibular head to the end of PTFJ on the simple oblique radiographs of 22 cases of tibial intramedullary (IM) nailing. The center (O) of the IM nailing, from the tibial anterior cortex at the level of insertion of an ObML-PIS, was measured on the simple lateral radiographs. The angle POA (P: a point 10 mm anterior from the anterior fibular border, A: a point on the tangent line from the O point to the posteromedial cortex of the fibula) was measured on the MR axial view of 60 cases, and within this angle an ObML-PIS could injure the important anatomical structures. Transverse and 45-degree oblique diameters of the proximal tibia on the MR axial view were also measured. RESULTS: The PTFJ length was 18.5+/-3.3 mm and the O point was located at 15.3+/-3.4 mm posterior from the tibial anterior cortex. The angle POA was 21.4+/-6.2-67.8+/-6.7 degrees with medial to lateral oblique directions. The transverse diameter of the proximal tibia was 58.0+/-5.8 mm and the 45-degree oblique diameter was 50.7+/-6.2 mm. CONCLUSION: Special caution may be needed when we use an ObML-PIS because it is located at the level distal from the end of the PTFJ and within the POA angle, and the peroneal nerve and anterior tibial artery can possibly be severed.

Survival and Prognostic Analysis of Adjacent Segments after Spinal Fusion

BACKGROUND: To examine the survival function and prognostic factors of the adjacent segments based on a second operation after thoracolumbar spinal fusion. METHODS: This retrospective study reviewed 3,188 patients (3,193 cases) who underwent a thoracolumbar spinal fusion at the author's hospital. Survival analysis was performed on the event of a second operation due to adjacent segment degeneration. The prognostic factors, such as the cause of the disease, surgical procedure, age, gender and number of fusion segments, were examined. Sagittal alignment and the location of the adjacent segment were measured in the second operation cases, and their association with the types of degeneration was investigated. RESULTS: One hundred seven patients, 112 cases (3.5%), underwent a second operation due to adjacent segment degeneration. The survival function was 97% and 94% at 5 and 10 years after surgery, respectively, showing a 0.6% linear reduction per year. The significant prognostic factors were old age, degenerative disease, multiple-level fusion and male. Among the second operation cases, the locations of the adjacent segments were the thoracolumbar junctional area and lumbosacral area in 11.6% and 88.4% of cases, respectively. Sagittal alignment was negative or neutral, positive and strongly positive in 47.3%, 38.9%, and 15.7%, respectively. Regarding the type of degeneration, spondylolisthesis or kyphosis, retrolisthesis, and neutral balance in the sagittal view was noted in 13.4%, 36.6%, and 50% of cases, respectively. There was a significant difference according to the location of the adjacent segment (p = 0.000) and sagittal alignment (p = 0.041). CONCLUSIONS: The survival function of the adjacent segments was 94% at 10 years, which had decreased linearly by 0.6% per a year. The likelihood of a second operation was high in those with old age, degenerative disease, multiple-level fusion and male. There was a tendency for the type of degeneration to be spondylolisthesis or kyphosis in cases of the thoracolumbar junctional area and strongly positive sagittal alignment, but retrolisthesis in cases of the lumbosacral area and neutral or positive sagittal alignment.

Spinal Cord Injury Caused by Bone Cement after Percutaneous Vertebroplasty : One Case of Long-term Follow-up and the Result of Delayed Removal / 대한정형외과학회잡지

Among the complications of percutaneous vertebroplasty, bone cement leakage into the spinal canal doesn't happen very often, but this could provoke a severe neurologic deficit. It is not certain whether this neurologic deficit may be permanent or reversible. Yet if the bone cement is left in the spinal canal, trivial events such as minor trauma could worsen the neurologic symptoms. The authors treated a 75-year-old female patient with Nurick's grade IV neurologic deficit, which was due to cement leakage into the spinal canal after previous vertebroplasty of T8 and T9. She had been having a neurologic deficit for 9 years, and it became aggravated after a minor trauma to Nurick's grade V. After the cement in the spinal canal was removed, her neurologic symptoms were improved to Nurick's grade II. Leaving a cement mass in the spinal canal may be a risk factor for additional neurologic injury even when suffering only a minor trauma, and the neurologic symptoms can be improved after removal of the cement, even for the case with a long-term neurological defect.

The Surgical Treatment for Spinal Intradural Extramedullary Tumors

BACKGROUND: We wanted to investigate the results of surgical treatment and analyze the factors that have an influence on the neurologic symptoms and prognosis of spinal intradural extramedullary (IDEM) tumors. METHODS: The spinal IDEM tumor patients (11 cases) who had been treated by surgical excision and who were followed up more than 1 year were retrospectively analyzed. Pain was evaluated by the visual analogue scale (VAS) and the neurologic function was assessed by Nurick's grade. The pathological diagnosis, the preoperative symptom duration, the tumor location on the sagittal and axial planes and the percentage of tumor occupying the intradural space were investigated. In addition, all these factors were analyzed in relation to the degree of the preoperative symptoms and the prognosis. On the last follow-up, the MRI was checked to evaluate whether or not the tumor had recurred. RESULTS: The most common diagnosis was schwannomas (73%), followed by meningiomas (18%). The percentage of tumor occupying the intradural space was 82.9 +/- 9.4%. The VAS score was reduced in all cases from 8.0 +/- 1.2 to 1.2 +/- 0.8 (p = 0.003) and the Nurick's grade was improved in all cases from 3.0 +/- 1.3 to 1.0 +/- 0.0 (p = 0.005). The preoperative symptoms were correlated with only the percentage of tumor occupying the intradural space (VAS; r2 = 0.75, p = 0.010, Nurick's grade; r2 = 0.69, p = 0.019). One case of schwannoma recurred. CONCLUSIONS: The degree of neurologic symptoms was correlated with the percentage of tumor occupying the intradural space. All the tumors were able to be excised through the posterior approach. The postoperative neurologic recovery was excellent in all the cases regardless of any condition. Therefore, aggressive surgical excision is recommended even for cases with a long duration of symptoms or a severe neurologic deficit.

The Effect of Demineralized Bone Matrix as a Graft Enhancer in Posterior Lumbar Interbody Fusion Using Cage and Local Bone Chips / 대한척추외과학회지

STUDY DESIGN: A randomized, controlled study OBJECTIVES: We wanted to investigate whether osteogenesis can be enhanced when a small amount of demineralized bone matrix (1 cc/segment) is mixed with local bone chips. SUMMARY OF LITERATURE REVIEW: Demineralized bone matrix (DBM) has been used for spinal arthrodesis. However, there are only a few reports about its use as a composite graft with local bone chips for posterior lumbar interbody fusion MATERIALS AND METHODS: Degenerative spine patients, who would normally be treated by decompression and posterior lumbar interbody fusion with using a pedicle screw system and one cage, were randomly, prospectively selected for whether they would be treated with using local bone chips mixed with 1cc of DBM (Group I: 15 patients and 19 segments) or local bone chips (Group II: 12 patients and 13 segments) for graft material. The sampling bias was investigated for gender, age, endocrine diseases, previous operation, habits (alcohol drinking, smoking), steroid medication, bone mineral density and the amount of local bone. The amount of bone formation was measured at 6 months after operation. On the sagittal and coronal reconstruction CT images, the bone formation outside of the cage was measured, and this was interpreted in a "blinded"fashion by 2 independent doctors who did not take part in the operations. RESULTS: There was no sampling bias between the 2 groups except for age (Group I= 65.3+/-7.1, Group II=58.9+/-6.0, p=0.010). The ratio of local bone chips and DBM was 5.98:1 in Group I. There was moderate concurrence between the 2 interpreters (kappa coefficiency= 0.494, p<0.001 for the sagittal plain images and kappa co-efficiency=0.467, p<0.001 for the coronal plain images) and Group I showed significantly more bone formation (p=0.003). CONCLUSION: DBM that is mixed with local bone chips, even with small amount, enhanced bone formation in the posterior lumbar interbody fusion. This is regarded to act as a graft enhancer to increase the fusion rate, even when using local bone chips for graft material, for the cases that show unfavorable conditions for fusion or for the cases that are prone to loosening of hardware.