• Journal of Korean Neurosurgical Society
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• v.42 no.3
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• pp.195-199
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• 2007

Objective : Bilateral laminotomy and unilateral laminotomy for bilateral decompression are becoming the minimally invasive procedures for lumbar spinal stenosis (LSS). With the aim of less invasiveness and better preservation of spinal stability. these techniques have been developed. But there are no large randomized studies to show the surgical results between these two techniques. The objective of this study was to examine the safety and efficacy of these two minimally invasive techniques. Methods : A total of 80 patients were included in this study (Group I : bilateral laminotomy, Group II : Unilateral laminotomy for bilateral decompression). Perioperative parameters and complications were analyzed. Symptoms and scores such as visual analog scale (VAS) scores, Oswestry Disability Index (ODI) scores, and SF-36 scores of prospectively accrued patients were assessed preoperatively and at 1 month and 12 months after surgery. Paired-t test, two-sample student-t tests, and non parametric tests were used to determine cross-sectional differences between two groups. Results : No major complications such as spinal instability or deaths occurred during follow-up periods. VAS, ODI scores and SF-36 body pain and physical function scores showed statistically significant improvements in both groups (p<0.001). The significant widening of the spinal canal diameter was also noted in both groups. But, in Group II. there were minor postoperative complications such as dural tear (2 cases 5.0%), fracture of ipsilateral inferior facet (1 case 2.5%), and 5 cases of transient leg symptoms of contralateral side. Conclusion : Both bilateral laminotomy and unilateral laminotomy for bilateral decompression allow achievement of adequate and long-lasting operative results in patients with LSS. But postoperative complications are more frequent in Group II (unilateral laminotomy and bilateral decompression). These results indicate that bilateral laminotomy is the preferred minimally invasive technique to treat symptomatic LSS.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1505-1513
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• 2000

Objectives : Many surgical procedures have been introduced to a symptomatic lumbar stenosis. Most of these procedures still have been regarded as an extensive surgical intervention with respect to normal aging process of the lumbar spine. We adopted a microsurgical decompression procedure via unilateral exposure as a minimally invasive intervention for symptomatic lumbar stenosis without instability. Materials and Methods : Fifty-seven patients with symptomatic lumbar stenosis underwent microsurgical decompression via unilateral laminotomy between March 1998 and December 1999. The conceptual modification and technical refinements were added to the previously reported microsurgical decompression procedure. Bilateral decompression through a unilateral laminotomy hole was performed in 11 patients. These patients profile also included 9 cases of degenerative spondylolisthesis(Grade I) without instability. Results : Preoperative neurogenic intermittent claudication(NIC) was more notably improved than low back pain, 60% to 82% during the follow-up period. Overall clinical results were excellent in 20(35%), good in 29(51%), fair in 6(11%) and poor in 2(3%). Conclusions : Microsurgical decompression for lumbar stenosis with stable spine provided a satisfactory symptomatic improvement without extensive destruction of the weight-bearing structures and functional mobile segments, even bilateral symptoms existed.

• Journal of Korean Neurosurgical Society
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• v.61 no.6
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• pp.680-688
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• 2018

Objective : To mitigate the risk of iatrogenic instability, new posterior decompression techniques able to preserve musculoskeletal structures have been introduced but never extensively investigated from a biomechanical point of view. This study was aimed to investigate the impact on spinal flexibility caused by a unilateral laminotomy for bilateral decompression, in comparison to the intact condition and a laminectomy with preservation of a bony bridge at the vertebral arch. Secondary aims were to investigate the biomechanical effects of two-level decompression and the quantification of the restoration of stability after posterior fixation. Methods : A universal spine tester was used to measure the flexibility of six L2-L5 human spine specimens in intact conditions and after decompression and fixation surgeries. An incremental damage protocol was applied : 1) unilateral laminotomy for bilateral decompression at L3-L4; 2) on three specimens, the unilateral laminotomy was extended to L4-L5; 3) laminectomy with preservation of a bony bridge at the vertebral arch (at L3-L4 in the first three specimens and at L4-L5 in the rest); and 4) pedicle screw fixation at the involved levels. Results : Unilateral laminotomy for bilateral decompression had a minor influence on the lumbar flexibility. In flexion-extension, the median range of motion increased by 8%. The bone-preserving laminectomy did not cause major changes in spinal flexibility. Two-level decompression approximately induced a twofold destabilization compared to the single-level treatment, with greater effect on the lower level. Posterior fixation reduced the flexibility to values lower than in the intact conditions in all cases. Conclusion : In vitro testing of human lumbar specimens revealed that unilateral laminotomy for bilateral decompression and bone-preserving laminectomy induced a minor destabilization at the operated level. In absence of other pathological factors (e.g., clinical instability, spondylolisthesis), both techniques appear to be safe from a biomechanical point of view.

• Journal of Korean Neurosurgical Society
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• v.47 no.5
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• pp.338-344
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• 2010

Objective : This study assessed the safety and efficacy of one level unilateral laminotomy bilateral decompression (ULBD) with the placement of a device for intervertebral assisted motion (DIAM) compared with one level ULBD only in elderly patients with degenerative lumbar spinal stenosis (DLSS). Methods : A non randomized prospective analysis was performed on 16 patients who underwent one level ULBD with DIAM (Group A) and 20 patients with one level ULBD only (Group B) between February 2007 and March 2008. Radiographic imaging, visual analog scale (VAS) and MacNab outcome scale were obtained before and after surgery at a mean interval of 21 months (range 17-27 months). Results : The disc height, interpedicular distance, slip distance and segmental lordotic angle were similar between two groups. In the group A, there was no significant difference between the pre- and post-operative imaging in terms of the sagittal balance and disc height. Both groups showed significant improvement in the clinical outcomes. In addition, there was significantly less low-back pain in the group A than in the group B at the last follow up, while the clinical improvement of the leg pain and MacNab outcome scale showed no significant difference in the two groups. There were no major complications or DIAM associated complications. Conclusion : ULBD with DIAM is a safe and efficacious treatment for selective elderly patients with DLSS, particularly for relieving low back pain comparing to ULBD. ULBD with DIAM did not alter the disc height or sagittal alignment at the mean 21 months follow-up interval.

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.194-200
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• 2013

Objective : Lumbar spine stenosis (LSS) can result in symptomatic compression of the neural elements, requiring surgical treatment if conservative management fails. Minimally invasive surgery has come to be more commonly used for the treatment of LSS. The current study describes outcomes of bilateral microdecompression by unilateral or bilateral laminotomy (BML) for degenerative LSS after a minimum follow-up period of 3 years and investigates factors that result in a poor outcome. Methods : Twenty-one patients who were followed-up for at least 3 years were included in this study. For clinical evaluation, the Japanese Orthopedic Association (JOA) scoring system for low back pain was used. The modified grading system of Finneson and Cooper was used for outcome assessment. Radiographic evaluation was also performed for spondylolisthesis, sagittal rotation angle, and disc height. Results : Twenty-one patients (10 men, 11 women) aged 53-82 years ($64.1{\pm}8.9$ years) were followed-up for a minimum of 3 years (36-69 months). During follow-up, two patients underwent reoperation. Average preoperative JOA score and clinical symptoms, except persistent low back pain, improved significantly at the latest follow-up. There were no significant differences in radiological findings preoperatively and postoperatively. Thirteen patients (61.9%) had excellent to fair outcomes. Conclusion : BML resulted in a favorable and persistent outcome for patients with degenerative LSS without radiological instability over a mid-term follow-up period. Persistent low back pain unrelated to postoperative instability adversely affects mid-term outcomes.

• Journal of Korean Neurosurgical Society
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• v.41 no.3
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• pp.207-209
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• 2007

We present an elderly patient with unilateral foraminal stenosis treated by isthmus resection. An 83-year-old female could not walk due to severe leg pain along right L5 sensory dermatome. Despite the laminotomy for spinal stenosis on the right side at the L4-5 level, her leg pain did not improve. Careful review of computed tomography scans and coronal source images of magnetic resonance myelography revealed foraminal stenosis on the right side at the L5 vertebra. Because of medical problem, she underwent isthmus resection on the right side at the L5 level instead of total facetectomy and fusion. After surgery, her leg pain was markedly improved. Isthmus resection showed successful result for this medically compromised elderly patient with unilateral foraminal stenosis.