Unilateral Laminectomy For Bilateral Decompression Research Articles

Comparative efficacy of unilateral biportal and percutaneous endoscopic techniques in unilateral laminectomy for bilateral decompression (ULBD) for lumbar spinal stenosis

BackgroundUnilateral laminotomy for bilateral decompression (ULBD) has yielded positive results in the treatment of lumbar spinal stenosis (LSS). Unilateral biportal ULBD (UB-ULBD) and percutaneous endoscopic ULBD (PE-ULBD) are gaining popularity because of the progress that has been made in minimally invasive surgery (MIS). The objective of this study was to evaluate and compare the radiographic and clinical results of UB-ULBD and PE-ULBD.MethodsThis study retrospectively enrolled patients who underwent ULBD surgery for LSS. The patients were categorized into two groups on the basis of the surgical method: the UB-ULBD group and the PE-ULBD group. Data on the general demographic data, surgical details, clinical efficacy, radiography and complications were compared between the two groups were compared. The minimum follow-up duration was 12 months.ResultsA total of 113 LSS patients who had undergone ULBD at our institution were included, of whom 61 patients underwent UB-ULBD surgery and 52 underwent PE-ULBD surgery. The UB-ULBD group had a significantly shorter operation time (P < 0.05). The facet was significantly better preserved in the UB-ULBD group than in the PE-ULBD group, and the angle of ipsilateral facet joint resection in the UE-ULBD group was significantly smaller (P < 0.05). The ODI score, VAS score and modified Macnab criteria improved postoperatively in both groups. The UB-ULBD group had a 95.08% rate of excellent or good patient outcomes, whereas the PE-ULBD group had a 92.30% rate.ConclusionBoth UB-ULBD and PE-ULBD can provide favourable clinical outcomes when used to treat LSS. UB-ULBD is beneficial because of its shorter operation time, smaller angle of ipsilateral facet joint resection and better facet preservation, making it a viable and safe option for treating LSS while ensuring spinal stability.

Lumbar Endoscopic Unilateral Laminectomy for Bilateral Decompression in Degenerative Spondylolisthesis

Degenerative spondylolisthesis is an important cause of chronic low back pain and radiculopathy in the adult U.S. Open decompression with or without fusion is considered the standard for management, yet optimal treatment remains controversial. Full endoscopic spine surgery offers an alternative surgical approach with possible advantages. There is a paucity of data on the use of full endoscopic spinal surgery in degenerative spondylolisthesis. Therefore, we present the clinical and radiographic outcomes of 73 patients with low-grade degenerative spondylolisthesis with severe stenosis, who underwent lumbar endoscopic unilateral laminectomy for bilateral decompression. Patients with low-grade degenerative spondylolisthesis who underwent a lumbar endoscopic ULBD at 6 spine centers in North America were included in this study. Patients were followed up at 3, 9, and 12 months. Static and dynamic imaging was performed and evaluated routinely before surgery to identify the pathology and grade of spondylolisthesis. Patient-reported outcomes were prospectively collected. This study included 73 patients from 6 spine centers. Sixty-two patients were diagnosed with grade I spondylolisthesis, whereas 11 were diagnosed with grade II spondylolisthesis. Postoperatively, 70 patients reported improved symptoms and pain resolution, whereas 3 patients reported worse pain. Mean visual analog scale back and visual analog scale leg scores and Oswestry Disability Index showed a statistically significant improvement at 3, 9, and 12 months compared with the preoperative period. Radiographically, no patient in our study had progression of the grade of spondylolisthesis. Patients with low-grade degenerative spondylolisthesis causing severe stenosis can safely be treated with lumbar endoscopic unilateral laminectomy for bilateral decompression. A head-to-head trial should be undertaken to provide a higher level of clinical evidence.

Severe Symptomatic Epidural Hematoma Following Percutaneous Endoscopic Unilateral Laminectomy for Bilateral Decompression (Endo-ULBD)-Series Report and Management Strategies.

Severe symptomatic epidural hematoma (SSEH) is one of the most severe complications following percutaneous endoscopic unilateral laminectomy for bilateral decompression (Endo-ULBD). Considering that this technique has been performed for a short time, no detailed reports have been recently published. Thus, it is critical to gain a better understanding of SSEH occurring in its postoperative period with regard to its incidence, possible causes, outcome, etc., in order to identify relevant management strategies. Patients with spinal stenosis who had undergone Endo-ULBD in our department from May 2019 to May 2022 were retrospectively analyzed. Of which, patients with postoperative epidural hematoma were followed-up. The preoperative and postoperative physical conditions of each patient were recorded, and the information related to hematoma removal surgery was recorded in detail. Clinical outcomes were assessed using the visual analogue scale (VAS) and Oswestry disability index (ODI), and the results were classified into "excellent," "good," "fair," or "poor" based on the modified MacNab criteria. The incidence of hematoma with different factors was calculated, and a bar graph was used to compare the difference of the indexes related to hematoma removal between cases, and a line graph was used to reflect the trend of the outcome of each patient within 6 months to evaluate the effect of the treatment. A total of 461 patients with spinal stenosis who underwent Endo-ULBD were enrolled in the study. SSEH occurred in four cases, with an incidence rate of 0.87% (4/461). All these four patients underwent decompression of multiple segments, and three of them had a history of hypertension comorbid with diabetes. Notably, one patient had a past history of hypertension and coronary artery disease and was on postoperative low molecular heparin due to lower extremity venous thrombosis. According to the conditions of the four patients, three types of treatment were used. And with timely treatment, all patients recovered well. Despite being a minimally invasive technique, postoperative epidural hematoma remains a severe complication of Endo-ULBD. Therefore, during percutaneous endoscopic surgery, it is essential to enhance the comprehensive perioperative management of patients with Endo-ULBD. Signs related to postoperative hematoma must be recognized and promptly managed. If necessary, satisfactory results can be achieved by using percutaneous endoscopy along the original surgical channel to remove the hematoma.

Outcomes after decompressive laminectomy for lumbar spinal stenosis: comparison between minimally invasive unilateral laminectomy for bilateral decompression versus open laminectomy.

Outcomes after decompressive laminectomy for lumbar spinal stenosis: comparison between minimally invasive unilateral laminectomy for bilateral decompression versus open laminectomy.

Lumbar Giant Disk Herniations Treated With a Unilateral Approach for Bilateral Decompression.

Disk herniations that obstruct the spinal canal by more than 50% are named "giant disk herniations" (GDHs). GDHs are challenging to treat from a surgical perspective because of their size and the risk of iatrogenic manipulation during resection resulting in additional neurological compromise. As a result, the appropriateness of minimally invasive tubular approaches for the treatment of lumbar GDHs remains controversial. To report our experience in treating lumbar GDHs using tubular minimally invasive surgery. A total number of 228 disk herniations were evaluated for the criteria of GDH. In addition, the presence of neurological deficits such as cauda equina syndrome, pain as measured by a visual analog scale, operating time, complications, estimated intraoperative blood loss, and number of surgical revisions were assessed. The standard tubular diskectomy technique was modified to include unilateral laminectomy for bilateral decompression before the diskectomy to create a sufficient working space for removal of the disk fragments. Twenty-three (10%) patients met the criteria for GDH. Clinically significant motor weakness was present in 21 patients (91.3%) before surgery, and 3 patients (13%) presented with cauda equina syndrome. The average mean visual analog scale (±SD) for the preoperative pain score was 8.3 and decreased to 2.4 at follow-up after surgery. All cases of cauda equina syndrome resolved postoperatively. Unilateral tubular minimally invasive surgery diskectomy seems to be a safe and effective treatment alternative for lumbar GDHs, combined with the "over-the-top" decompression, which provides bilateral decompression and working space.

Effects of the difference between lumbar lordosis in the supine and standing positions on the clinical outcomes of decompression surgery for lumbar spinal stenosis.

The authors sought to evaluate the relationship between the difference in lumbar lordosis (DiLL) in the preoperative supine and standing positions and spinal sagittal alignment in patients with lumbar spinal stenosis (LSS) and to determine whether this difference affects the clinical outcome of laminectomy. Sixty patients who underwent single-level unilateral laminectomy for bilateral decompression of LSS were evaluated. Spinopelvic parameters in the supine and standing positions were measured preoperatively and at 3 months and 2 years postoperatively. DiLL between the supine and standing positions was determined as follows: DiLL = supine LL - standing LL. On the basis of this determination patients were then categorized into DiLL(+) and DiLL(-) groups. The relationship between DiLL and preoperative spinopelvic parameters was evaluated using Pearson's correlation coefficient. In addition, clinical outcomes such as visual analog scale (VAS) and Oswestry Disability Index (ODI) scores between the two groups were measured, and their relationship to DiLL was evaluated using two-group comparison and multivariate analysis. There were 31 patients in the DiLL(+) group and 29 in the DiLL(-) group. DiLL was not associated with supine LL but was strongly correlated with standing LL and pelvic incidence (PI) - LL (PI - LL). In the preoperative spinopelvic alignment, LL and SS in the standing position were significantly smaller in the DiLL(+) group than in the DiLL(-) group, and PI - LL was significantly higher in the DiLL(+) group than in the DiLL(-) group. There was no difference in the clinical outcomes 3 months postoperatively, but low-back pain, especially in the sitting position, was significantly higher in the DiLL(+) group 2 years postoperatively. DiLL was associated with low-back pain in the sitting position, which was likely to persist in the DiLL(+) group postoperatively. We evaluated the relationship between DiLL and spinal sagittal alignment and the influence of DiLL on postoperative outcomes in patients with LSS. DiLL was strongly correlated with PI - LL, and in the DiLL(+) group, postoperative low-back pain relapsed. DiLL can be useful as a new spinal alignment evaluation method that supports the conventional spinal sagittal alignment evaluation.

Minimally Invasive Microscopic Decompression for Focal Lumbar Spinal Canal Stenosis

Abstract Background: Lumbar canal stenosis is the reduction of the surface area of the spinal canal and it is a prevalent disease which has several etiologies. It is a gradual degenerative and aging process. The cut off is the anteroposterior diameter is 12mm of the spinal canal below that it is relative stenosis and below 10mm it is absolute stenosis. Causes of canal stenosis include congenital and acquired causes (degenerative, spond-ylolithetic and iatrogenic). It is anatomically classified into central, lateral recess foraminal and extraforaminal. Micro-scopic unilateral laminectomy for bilateral decompression is a recently developed minimally invasive technique for decom-pression of the spinal canal with unilateral exposure minimizing soft tissue trauma. Aim of Study: To evaluate the outcome of the procedure and its efficacy in relieving symptoms. Patients and Methods: A prospective study including 32 patients with single level focal lumbar canal stenosis were included, perioperative assessment with history taking full neurological examination VAS score for pain is done, all had minimally invasive microscopic decompression via a unilateral approach postoperative status complications VAS score was done at 1,3 and 6th months intervals also patient satisfaction was considered. Results: Thirty two patients were included all had focal type stenosis, 27 at L4, 4 at L3 and one at L5. Sixty percent relieved at first month ,95% at 3 month and five percent were not satisfied. Conclusion: The technique is a good option with fast recovery and early ambulation with less post-operative back pain.

Minimally invasive approaches to the surgical treatment of lumbar stenosis

A literature review of minimally invasive treatment options for lumbar spinal stenosis was conducted to determine the efficacy and outcomes of existing and evolving techniques. This study focuses on minimally invasive interlaminar decompression, unilateral laminectomy for bilateral decompression, and internal indirect decompression devices/interlaminar stabilization. We found that both minimally invasive interlaminar decompression and unilateral laminectomy for bilateral decompression can lead to acceptable and effective outcomes for patients with lumbar spinal stenosis. Indirect decompression via devices that provide interlaminar stabilization, including the Superion, X-STOP, and Coflex implants, has led to mixed results, but further research is still required.

Unilateral laminectomy for bilateral decompression improves low back pain while standing equally on both sides in patients with lumbar canal stenosis: analysis using a detailed visual analogue scale

BackgroundUnilateral laminectomy for bilateral decompression (ULBD) for lumbar spinal stenosis (LSS) is a less invasive technique compared to conventional laminectomy. Recently, several authors have reported favorable results of low back pain (LBP) in patients of LSS treated with ULBD. However, the detailed changes and localization of LBP before and after ULBD for LSS remain unclear. Furthermore, unsymmetrical invasion to para-spinal muscle and facet joint may result in the residual unsymmetrical symptoms. To clarify these points, we conducted an observational study and used detailed visual analog scale (VAS) scores to evaluate the characteristics and bilateral changes of LBP and lower extremity symptoms.MethodsWe included 50 patients with LSS treated with ULBD. A detailed visual analogue scale (VAS; 100 mm) score of LBP in three different postural positions: motion, standing, and sitting, and bilateral VAS score (approached side versus opposite side) of LBP, lower extremity pain (LEP), and lower extremity numbness (LEN) were measured. Oswestry Disability Index (ODI) was used to quantify the clinical improvement.ResultsDetailed LBP VAS score before surgery was 51.5 ± 32.5 in motion, 63.0 ± 30.1 while standing, and 37.8 ± 31.8 while sitting; and showed LBP while standing was significantly greater than LBP while sitting (p < 0.01). After surgery, LBP while standing was significantly improved relative to that while sitting (p < 0.05), and levels of LBP in the three postures became almost the same with ODI improvement. Bilateral VAS scores showed significant improvement equally on both sides (p < 0.01).ConclusionsULBD improves LBP while standing equally on both sides in patients with LCS. The improvement of LBP by the ULBD surgery suggests radicular LBP improved because of decompression surgery. Furthermore, the symmetric improvement of LBP by the ULBD surgery suggests unsymmetrical invasion of the paraspinal muscles and facet joints is unrelated to residual LBP.

Minimally Invasive Lumbar Spinal Decompression in Elderly Patients with Magnetic Resonance Imaging Morphological Analysis.

Study DesignCase-control study.PurposeIn this study, we aimed to investigate clinical outcomes and morphological features in elderly patients with lumbar spinal stenosis (LSS) who were treated by minimally invasive surgery (MIS) unilateral laminectomy for bilateral decompression (ULBD) using a tubular retractor.Overview of LiteratureNumerous methods using imaging have been attempted to describe the severity of spinal stenosis. But the relationship between clinical symptoms and radiological features remains debatable.ObjectiveIn this study, we aimed to investigate clinical outcomes and morphological features in elderly patients with LSS who were treated by MIS-ULBD.MethodsWe methodically assessed 85 consecutive patients aged >65 years who were treated for LSS. The patients were retrospectively analyzed in two age groups: 66–75 years (group 1) and >75 years (group 2). Clinical outcomes were assessed using the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and the modified MacNab criteria. Outcome parameters were compared between the groups at the 1-year follow-up. Core radiologic parameters for central and lateral stenosis were analyzed and clinical findings of the groups were compared.ResultsAt the 1-year follow-up, patients in both groups 1 and 2 demonstrated significant improvement in their VAS and ODI scores. All clinical outcomes, except postoperative ODI, were not significantly difference between the groups. In addition, no significant difference was noted in the preoperative radiological parameters between the groups. There was no statistically significant correlation between radiological parameters and clinical symptoms or their outcomes. Moreover, no differences were noted in perioperative adverse events and in the need for repeat surgery at follow-ups between the groups.ConclusionsMIS-ULBD by tubular approach is a safe and effective treatment option for elderly patients with LSS. Clinical outcomes in patients with LSS and aged >75 years were comparable with those in patients with LSS and aged 66–75 years. Moreover, we did not find any correlation between radiological parameters and clinical outcomes in either of the two patient groups.

Treatment of Lumbar Spinal Stenosis by Microscopic Unilateral Laminectomy for Bilateral Decompression: A Technical Note.

Lumbar spinal stenosis is typically a degenerative condition that leads to compression of the spinal canal and lateral recess, resulting in leg pain and walking disability. Surgical management is indicated after failure of non-surgical management or rapidly worsening neurological impairment. The traditional approach is a laminectomy with foraminotomy and partial facetectomy but a newer minimally invasive option, unilateral laminectomy for bilateral decompression (ULBD), seems to demonstrate the better postoperative outcomes due to its unilateral exposure. ULBD involves a midline incision, opening the thoracolumbar fascia, retracting the paravertebral muscles unilaterally, then a hemilaminectomy, flavectomy, and decompression of the spinal canal with foraminotomy or partial facetectomy. The clinical decision on which side to approach spinal stenosis with ULBD has not been discussed in the literature. We have come up with an algorithm to decide which side to approach for ULBD based on position of spinous process and angulation, side of maximal compression, and surgeon handedness.

Minimally Invasive Unilateral Laminectomy for Bilateral Decompression

Unilateral laminectomy for bilateral decompression (ULBD) is a recently popularized minimally invasive surgical technique for decompression of the spinal canal. With the patient prone on the spinal table of your choice, use an image intensifier to determine the incision position and then position the retractor of your choice to identify the inferior aspect of the superior lamina. Begin the laminotomy on the approach side, drilling to identify the ligamentum flavum on the approach side, and remove bone up to the superior attachment of the ligamentum flavum. To gain access to the contralateral side of the canal for bilateral decompression, remove enough of the spinous process to gain access to the midline and contralateral ligamentum flavum. The superior aspect of the decompression usually corresponds with the superior ligamentum flavum attachment, except in certain cases such as when a facet joint cyst extends beyond the limits of the ligamentum flavum; removal of the upper limit of the ligamentum flavum provides an important landmark to confirm the superior limit of the decompression. Detach the ligamentum flavum from the facet joint on the approach side using a combination of angled curets and Kerrison rongeurs; a partial medial facetectomy, or removal of adequate facet hypertrophy, on the approach side is necessary to expose the traversing nerve root. Decompression of the thecal sac on the contralateral side of the canal is the potentially dangerous aspect of the procedure, with the highest risk of dural injury and a cerebrospinal fluid leak; thus, create enough room on the ipsilateral side so that instruments can be safely introduced into the canal for the contralateral decompression. Reducing the paraspinal muscle dissection substantially reduces iatrogenic muscle injury and blood loss, and oozing from the bone removal can be easily controlled with bone wax or a variety of hemostatic agents. Closure of a unilateral muscle exposure is rapid and the use of wound drainage is very rare, further reducing operative time as well as exposure to complications related to wound drains and subsequent infection risk. One of us (R.M.) and colleagues5 conducted a prospective randomized trial comparing ULBD with open laminectomy for degenerative lumbar spinal stenosis in 54 patients (27 in each arm of the study) treated from 2007 to 2009.

Minimally Invasive Versus Open Laminectomy for Lumbar Stenosis: A Systematic Review and Meta-Analysis.

Systematic review with meta-analysis. To assess the relative merits of minimally invasive unilateral laminectomy for bilateral decompression (ULBD) versus open laminectomy, a systematic review and meta-analysis of all available evidence was performed. Lumbar spinal stenosis is one of the most common pathologies in the increasingly elderly population that results in claudication, back and leg pain, and disability. The conventional approach for decompression is open laminectomy. In recent years, there has been a surge in microendoscopic procedures, which aim to minimize invasiveness. Despite the increasing use of these minimally invasive techniques, few studies have directly compared the safety, efficacy, and outcomes of these procedures with conventional laminectomy. There is a lack of robust clinical evidence, with most reports limited to single-center, inadequately powered, noncomparative studies. Relevant articles were identified from six electronic databases. Predefined endpoints were extracted and meta-analyzed from the identified studies. Satisfaction rates were significantly higher in the minimally invasive group (84% vs. 75.4%; P = 0.03), whereas back pain Visual Analog Scale scores were lower (P < 0.00001). Minimally invasive laminectomy operative duration was 11 minutes longer than the open approach (P = 0.001), however this may not have clinical significance. However, there was less blood loss (P < 0.00001) and shorter hospital stay (2.1 days; P < 0.0001). Dural injuries and cerebrospinal fluid leaks were comparable, but reoperation rates were lower in the minimally invasive cohort (1.6% vs. 5.8%; P = 0.02); however this was not significant when only randomized evidence was considered. The pooled evidence suggests ULBD may be associated with less blood loss and shorter stay, with similar complication profiles to the open approach. These findings warrant verification in large prospective registries and randomized trials. 1.

Comparative Study of Unilateral Laminotomy versus Conventional Laminectomy

Introduction Prolapsed intervertebral disc and lumbar canal stenosis have been major challenging problem of mankind since ages. Many different methods have been evolved for its diagnosis and management. The purpose of this study is to determine the efficacy and safety of unilateral laminotomy for decompression in case of PIVD and lumbar canal stenosis compared with conventional laminectomy. Materials and Methods A retrospective and prospective study of 40 patients who had undergone surgery for PIVD or lumbar canal stenosis at our institute was performed. They were assigned in the two groups: Group 1 ( n = 20) consisted of patients who underwent laminotomy for decompression, and Group 2 ( n = 20) consisted of patients treated by decompressive laminectomy. Neurological status of the patients was evaluated by physical examination both pre- and postoperatively. Pain, disability, and other criteria were assessed by Greenough scoring system. Plain AP and lateral radiographs and MRI of concerned segment of every patient were obtained. Lumbar flexion-extension films were obtained to assess spinal instability. Minimum follow-up was done at 6 months and results were assessed by using Greenough scoring system and radiographs at final follow-up. Results Excellent clinical outcome was obtained in 80% of patients in Group 1 and in 65% of patients in Group 2. Increase in Greenough score was more in Group 1. Postoperative spinal instability occurred in four patients in Group 2, none in Group 1. Early rehabilitation and early return to work was more possible in Group 1. There was one surgical complication in the each group (dural tear dealt during surgery). Postoperative infection developed in four patients (two in each group) among which one require surgical debridement in Group 2. Neurological impairment occurred in one patient in Group 2. Conclusion Duration of hospital stay is significantly reduced amongst the patients operated by unilateral laminotomy compared with laminectomy, and rehabilitation was also faster by starting earlier sitting and thereby reducing morbidity and burden to hospital. Consequent earlier return to normal routine life can be expected. Although overall outcome of the patients at final follow-up remains mostly unchanged, technique of sparing unilateral paraspinal muscles and thereby sparing supraspinous and interspinous ligaments does help in earlier rehabilitations of the patients, fastens the recovery, and thereby reducing psychiatric problems related to it, saves many man hours of one's life going in wastage and brings in overall feeling of well-being and patient satisfaction. Disclosure of Interest None declared References Young S, Veerapen R, O’Laoire SA. Relief of lumbar canal stenosis using multilevel subarticular fenestrations as an alternative to wide laminectomy: preliminary report. Neurosurgery 1988;23(5):628–633 Spetzger U, Bertalanffy H, Naujokat C, von Keyserlingk DG, Gilsbach JM. Unilateral laminotomy for bilateral decompression of lumbar spinal stenosis. Part I: Anatomical and surgical considerations. Acta Neurochir (Wien) 1997;139(5):392–396 Weiner BK, Walker M, Brower RS, McCulloch JA. Microdecompression for lumbar spinal canal stenosis. Spine 1999;24(21):2268–2272 Cavuşoğlu H, Türkmenoğlu O, Kaya RA, et al. Efficacy of unilateral laminectomy for bilateral decompression in lumbar spinal stenosis. Turk Neurosurg 2007;17(2):100–108 Guiot BH, Khoo LT, Fessler RG. A minimally invasive technique for decompression of the lumbar spine. Spine 2002;27(4):432–438 Kim SW, Ju CI, Kim CG, Lee SM, Shin H. Minimally invasive lumbar spinal decompression: a comparative study between bilateral laminotomy and unilateral laminotomy for bilateral decompression. J Korean Neurosurg Soc 2007;42(3):195-199 Greenough CG, Fraser RD. Assessment of outcome in patients with low-back pain. Spine 1992;17(1):36–41 Greenough CG. Results of treatment of lumbar spine disorders. Effects of assessment techniques and confounding factors. Acta Orthop Scand Suppl 1993;251(Suppl 251):126–129

Surgical Experience of Unilateral Laminectomy for Bilateral Decompression (ULBD) of Ossified Ligamentum Flavum in the Thoracic Spine

We describe a new surgical technique for the treatment of ossified ligamentum flavum (OLF) in the thoracic spine through unilateral laminectomy for bilateral decompression (ULBD). We reviewed the clinical data of 11 consecutive adult patients who had undergone ULBD for OLF between August 2004 and July 2008. Four patients underwent simultaneous decompressive surgery for cervical or lumbar lesions. The duration of symptoms was 25.4 months. Using clinical charts and mailed questionnaires, we evaluated the patients by pre- and postoperative Japanese Orthopaedic Association (JOA) scores and recovery rates. The mean follow-up period was 10.09 months (range: 3-35 months). The average age was 54.5 years (range: 34-78 years). The mean preoperative JOA score was 6.6. This improved to 8.8 in the follow-up study. The recovery rate was 33.2%. The cross-sectional area of the pre- and postoperative dural sac at the level of the stenosis was 57.56 mm(2) and 111.8 mm(2) respectively (p<0.0001). There was no operation-related transfusion, and there was no evidence of postoperative instability in the follow-up examination. ULBD is a safe and effective non-fusion technique that provides a good surgically decompressed field. A potential increase in kyphosis following laminectomy can be avoided by this surgical technique, also it preserves the contralateral facet joint, the lamina and the midline ligament structures, while widening the spinal canal.