Sung Myung Lee

Short Segment Screw Fixation without Fusion for Unstable Thoracolumbar and Lumbar Burst Fracture : A Prospective Study on Selective Consecutive Patients

Objective The purpose of this prospective study was to evaluate the efficacy and safety of screw fixation without bone fusion for unstable thoracolumbar and lumbar burst fracture. Methods Nine patients younger than 40 years underwent screw fixation without bone fusion, following postural reduction using a soft roll at the involved vertebra, in cases of burst fracture. Their motor power was intact in spite of severe canal compromise. The surgical procedure included postural reduction for 3 days and screw fixations at one level above, one level below and at the fractured level itself. The patients underwent removal of implants 12 months after the initial operation, due to possibility of implant failure. Imaging and clinical findings, including canal encroachment, vertebral height, clinical outcome, and complications were analyzed. Results Prior to surgery, the mean pain score (visual analogue scale) was 8.2, which decreased to 2.2 at 12 months after screw fixation. None of the patients complained of worsening of pain during 6 months after implant removal. All patients were graded as having excellent or good outcomes at 6 months after implant removal. The proportion of canal compromise at the fractured level improved from 55% to 35% at 12 months after surgery. The mean preoperative vertebral height loss was 45.3%, which improved to 20.6% at 6 months after implant removal. There were no neurological deficits related to neural injury. The improved vertebral height and canal compromise were maintained at 6 months after implant removal. Conclusion Short segment pedicle screw fixation, including fractured level itself, without bone fusion following postural reduction can be an effective and safe operative technique in the management of selected young patients suffering from unstable burst fracture.

The Role of Bone Cement Augmentation in the Treatment of Chronic Symptomatic Osteoporotic Compression Fracture

OBJECTIVE Bone cement augmentation procedures such as percutaneous vertebroplasty and balloon kyphoplasty have been shown to be effective treatment for acute or subacute osteoporotic vertebral compression fractures. The purpose of this study was to determine the efficacy of bone cement augmentation procedures for long standing osteoporotic vertebral compression fracture with late vertebral collapse and persistent back pain. METHODS Among 278 single level osteoporotic vertebral compression fractures that were treated by vertebral augmentation procedures at our institute, 18 consecutive patients were included in this study. Study inclusion was limited to initially, minimal compression fractures, but showing a poor prognosis due to late vertebral collapse, intravertebral vacuum clefts and continuous back pain despite conservative treatment for more than one year. The subjects included three men and 15 women. The mean age was 70.7 with a range from 64 to 85 years of age. After postural reduction for two days, bone cement augmentation procedures following intraoperative pressure reduction were performed. Imaging and clinical findings, including the level of the vertebra involved, vertebral height restoration, injected cement volume, local kyphosis, clinical outcome and complications were analyzed. RESULTS The mean follow-up period after bone cement augmentation procedures was 14.3 months (range 12-27 months). The mean injected cement volume was 4.1 mL (range 2.4-5.9 mL). The unipedicular approach was possible in 15 patients. The mean pain score (visual analogue scale) prior to surgery was 7.1, which decreased to 3.1 at 7 days after the procedure. The pain relief was maintained at the final follow up. The kyphotic angle improved significantly from 21.2 ± 4.9° before surgery to 10.4 ± 3.8° after surgery. The fraction of vertebral height increased from 30% to 60% after bone cement augmentation, and the restored vertebral height was maintained at the final follow up. There were no serious complications related to cement leakage. CONCLUSION In the management of even long-standing osteoporotic vertebral compression fracture for over one year, bone cement augmentation procedures following postural reduction were considered safe and effective treatment in cases of non-healing evidence.

Short Segment Fixation for Thoracolumbar Burst Fracture Accompanying Osteopenia : A Comparative Study

Objective The purpose of this study was to compare the results of three types of short segment screw fixation for thoracolumbar burst fracture accompanying osteopenia. Methods The records of 70 patients who underwent short segment screw fixation for a thoracolumbar burst fracture accompanying osteopenia (-2.5< mean T score by bone mineral densitometry <-1.0) from January 2005 to January 2008 were reviewed. Patients were divided into three groups based on whether or not bone fusion and bone cement augmentation procedure 1) Group I (n=26) : short segment fixation with posterolateral bone fusion; 2) Group II (n=23) : bone cement augmented short segment fixation with posterolateral bone fusion; 3) Group III (n=21) : bone cement augmented, short segment percutaneous screw fixation without bone fusion. Clinical outcomes were assessed using a visual analogue scale and modified MacNabs criteria. Radiological findings, including kyphotic angle and vertebral height, and procedure-related complications, such as screw loosening or pull-out, were analyzed. Results No significant difference in radiographic or clinical outcomes was noted between patients managed using the three different techniques at last follow up. However, Group I showed more correction loss of kyphotic deformities and vertebral height loss at final follow-up, and Group I had higher screw loosening and implant failure rates than Group II or III. Conclusion Bone cement augmented procedure can be an efficient and safe surgical techniques in terms of achieving better outcomes with minimal complications for thoracolumbar burst fracture accompanying osteopenia.

Screw Fixation without Fusion for Low Lumbar Burst Fracture : A Severe Canal Compromise But Neurologically Intact Case

The low lumbar spine is deeply located in flexible segments, and has a physiologic lordosis. Therefore, burst fractures of the low lumbar spine are uncommon injuries. The treatment for such injuries may either be conservative or surgical management according to canal compromise and the neurological status. However, there are no general guidelines or consensus for the treatment of low lumbar burst fractures especially in neurologically intact cases with severe canal compromise. We report a patient with a burst fracture of the fourth lumbar vertebra, who was treated surgically but without fusion because of the neurologically intact status in spite of severe canal compromise of more than 85%. It was possible to preserve motion segments by removal of screws at one year later. We also discuss why bone fusion was not necessary with review of the relevant literature.

Implant removal after percutaneous short segment fixation for thoracolumbar burst fracture : does it preserve motion?

Objective The purpose of this study was to evaluate the efficacy of implant removal of percutaneous short segment fixation after vertebral fracture consolidation in terms of motion preservation. Methods Between May 2007 and January 2011, 44 patients underwent percutaneous short segment screw fixation due to a thoracolumbar burst fracture. Sixteen of these patients, who underwent implant removal 12 months after screw fixation, were enrolled in this study. Motor power was intact in all patients, despite significant vertebral height loss and canal compromise. The patients were divided into two groups by degree of osteoporosis : Group A (n=8), the non-osteoporotic group, and Group B (n=8), the osteoporotic group. Imaging and clinical findings including vertebral height loss, kyphotic angle, range of motion (ROM), and complications were analyzed. Results Significant pain relief was achieved in both groups at final follow-up versus preoperative values. In terms of vertebral height loss, both groups showed significant improvement at 12 months after screw fixation and restored vertebral height was maintained to final follow-up in spite of some correction loss. ROM (measured using Cobbs method) in flexion and extension in Group A was 10.5° (19.5/9.0°) at last follow-up, and in Group B was 10.2° (18.8/8.6°) at last follow-up. Both groups showed marked improvement in ROM as compared with the screw fixation state, which was considered motionless. Conclusion Removal of percutaneous implants after vertebral fracture consolidation can be an effective treatment to preserve motion regardless of osteoporosis for thoracolumbar burst fractures.

Repeated migration of a fusion cage after posterior lumbar interbody fusion.

Although posterior lumbar interbody fusion (PLIF) is a widely accepted procedure, perioperative and postoperative complications are still encountered. In particular, cage migration can result in severe sequelae, and revision surgery is technically demanded. Here, we report a rare case of repeated migration of a fusion cage after PLIF. To the best of our knowledge, no report has been previously issued on repeated migration of a fusion cage after PLIF. The authors discuss the radiological and clinical findings of this unusual complication with a review of the literature.

Ligamentum Flavum Hematoma in the Adjacent Segment after a long Level Fusion.

Ligamentum flavum hematoma (LFH) is a very rare condition of dural compression; most are observed in the mobile cervical and lumbar spine regions. A 67-year-old man who had a long level interbody fusion at L3-S1 four years ago presented with symptoms suggestive of dural compression. Magnetic resonance imaging showed a posterior semicircular mass located at the adjacent L2-L3 level. After decompression of the spinal canal and removal of the mass lesion, pathological examination of the surgical specimen revealed a hematoma within the ligamentum. The patient fully recovered to normal status after surgery. Here, we report our experience with a LFH in the adjacent segment after a long level fusion procedure and discuss the possible associated mechanisms.

Emergent Endovascular Embolization for Iatrogenic Vertebral Artery Injury during Cervical Discectomy and Fusion

Injury to the vertebral artery during anterior cervical discectomy is rare but potentially fatal. We report a case of cerebellar infarction after endovascular embolization for iatrogenic vertebral artery injury at C5-C6 during an anterior cervical discectomy and fusion. A 61-year-old man had an intraoperative injury of the right vertebral artery that occurred during anterior cervical discectomy and fusion at C5-C6. Hemorrhage was not controlled successfully by packing with surgical hemostatic agents. While the patient was still intubated, an emergency angiogram was performed. The patient underwent endovascular occlusion of the right V2 segment with coils. After the procedure, his course was uneventful and he did not show any neurologic deficits. Brain computed tomographic scans taken 3 days after the operation revealed a right cerebellar infarction. Anti-coagulation medication was administered, and at 3-month follow-up examination, he had no neurologic sequelae in spite of the cerebellar infarction.

Posterior Lumbar Interbody Fusion Using an Unilateral Cage: A Prospective Study of Clinical Outcome and Stability

Objective The purpose of this study was to evaluate the clinical and radiological results of instrumented posterior lumbar interbody fusion (PLIF) using an unilateral cage. Methods Seventeen patients with unilateral radiculopathy who underwent bilateral percutaneous screw fixation with a single fusion cage inserted on the symptomatic side for treatment of focal degenerative lumbar spine disease were prospectively enrolled in this study. Their clinical results, radiological parameters, and related complications were assessed 10 days, 3 months, and 12 months postoperatively. Results There was no pseudarthrosis, instrumented fusion failure, significant cage subsidence, or retropulsion in any patient. The surgery restored the disc space height and maintained it as of 12 months postoperatively and did not exacerbate the lumbar lordotic and scoliotic angles. All patients had excellent or good outcomes according to the modified MacNabs criteria. The mean pain score according to the visual analogue scale was 7.5 preoperatively but had improved to 2.5 when reassessed 3 months postoperatively. The improvement was maintained as of 12 months postoperatively. Conclusion In cases of uncomplicated unilateral radiculopathy, PLIF using a single cage can be an effective and safe procedure with the advantage of preserving the posterior elements of the contralateral side. A shorter operative time and greater cost-effectiveness than for PLIF using bilateral cages can be expected.

Paraspinal Muscle Sparing Versus Percutaneous Screw Fixation: A Comparative Enzyme Study of Tissue Injury during the Treatment of L4-L5 Spondylolisthesis

Objective Screw fixation via the paraspinal muscle sparing approach and by percutaneous screw fixation are known to diminish the risk of complications, such as, iatrogenic muscle injury as compared with the conventional midline approach. The purpose of this study was to evaluate tissue injury markers after these less traumatic screw fixation techniques for the treatment of L4-L5 spondylolisthesis. Methods Twenty-two patients scheduled for posterior lumbar interbody fusion (PLIF) at the L4-L5 segment for spondylolisthesis were prospectively studied. Patients were divided into two groups by screw fixation technique (Group I: paraspinal muscle sparing approach and Group II: percutaneous screw fixation). Levels of serum enzymes representing muscle injury (CK-MM and Troponin C type 2 fast), pro-inflammatory cytokine (IL-8), and anti-inflammatory cytokine (IL-1ra) were analyzed using ELISA techniques on the day of the surgery and 1, 3, and 7 days after the surgery. Results Serum CK-MM, Troponic C type 2 fast (TNNC2), and IL-1ra levels were significantly elevated in Group I on postoperative day 1 and 3, and returned to preoperative levels on postoperative day 7. No significant intergroup difference was found between IL-8 levels despite higher concentrations in Group I on postoperative day 1 and 3. Conclusion This study shows that percutaneous screw fixation procedure is the preferable minimally invasive technique in terms of minimizing muscle injury associated with L4-L5 spondylolisthesis.