Unilateral Laminectomy Research Articles

Learning curve and complications of unilateral biportal endoscopy unilateral laminectomy bilateral decompression for lumbar spinal stenosis

Learning curve and complications of unilateral biportal endoscopy unilateral laminectomy bilateral decompression for lumbar spinal stenosis

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.

Unilateral biportal endoscopy vs. open decompression for lumbar epidural lipomatosis-cohort study using a prospective registry.

This study aimed to compare the outcomes of unilateral biportal endoscopy, unilateral laminectomy bilateral decompression (UBE-ULBD), and open lumbar decompression (OLD) in patients with lumbar epidural lipomatosis (LEL). This prospective observational study was conducted from March 2019 to May 2022 and encompassed 33 patients with LEL who underwent lumbar decompression. The study included 15 cases of UBE-ULBD decompression and 18 cases of open decompression, which were followed up for 1 year. The baseline characteristics, initial clinical manifestations, and surgical details [including estimated blood loss (EBL) and preoperative complications] of all patients were recorded. Radiographic evaluation included the cross-sectional area (CSA) of the thecal sac and paraspinal muscles on MRI. Clinical results were analyzed using the Short Form-36 Score (SF-36), the Numeric Pain Rating Scale (NRS) for lumbar and leg pain, creatine kinase, the Roland and Morris Disability Questionnaire (RMDQ), and the Oswestry Disability Index (ODI). The dural sac CSA increased considerably at the 1-year postoperative follow-up in both groups (p < 0.001). The operative duration in the OLD group (48.2 ± 7.2 min) was shorter than that in the UBE-ULBD group (67.7 ± 6.3 min, p < 0.001). The OLD group (97.2 ± 19.8 mL) was associated with more EBL than the UBE-ULBD group (40.6 ± 13.6 mL, p < 0.001). The duration of hospitalization in the OLD group (5.4 ± 1.3 days) was significantly longer compared with the UBE-ULBD group (3.5 ± 1.2 days, p < 0.01). The SF-36, NRS, RMDQ, and ODI scores improved in both groups postoperatively (p < 0.001). Serum creatine kinase values in the UBE-ULBD group (101.7 ± 15.5) were significantly lower than those in the OLD group (330.8 ± 28.1 U/L) 1 day after surgery (p < 0.001). The degree of paraspinal muscle atrophy in the UBE-ULBD group (4.81 ± 1.94) was significantly lower than that in the OLD group (12.15 ± 6.99) at 1 year (p < 0.001). UBE-ULBD and OLD demonstrated comparable clinical outcomes in treating LEL. However, UBE-ULBD surgery was associated with shorter hospital stays, lower rates of incision infection, lighter paravertebral muscle injury, and lower EBL than OLD surgery. Consequently, UBE-ULBD can be recommended in patients with LEL if conservative treatment fails.

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.

Comparison of biportal endoscopic technique and uniportal endoscopic technique in Unilateral Laminectomy for Bilateral Decomprssion (ULBD) for lumbar spinal stenosis

ObjectiveUnilateral laminotomy for bilateral decompression (ULBD) has been adopted widely to treat lumbar spinal stenosis (LSS). The objective of the study is to investigate clinical and radiological outcomes of the biportal endoscopic ULBD (BE-ULBD) and uniportal endoscopic ULBD (UE-ULBD). MethodsWe collected retrospectively 65 patients’ data who met the inclusion criteria (July 2019–June 2021). 33 patients underwent BE-ULBD surgery, and 32 patients underwent the UE-ULBD surgery, and were followed up for at least 1 year. The following preoperative and postoperative outcomes were compared between groups: the visual analog scale (VAS) for pain, the Oswestry disability index (ODI) for nerve function, and modified Macnab criteria for satisfaction, the cross-sectional area of the dural sac (DSCSA), the mean angle of facetectomy. ResultsAge, BMI, gender, levels of involvement and duration of symptoms were not significantly different at baseline in this study. Clinical data showed that postoperative ODI, VAS scores and Modified Macnab Criteria were not statistically different between the two groups. The BE-ULBD group had a shorter operation time than the UE-ULBD group (P < 0.001). Patients in the BE-ULBD group had a larger postoperative expansion of DSCSA expansion postoperatively (85.58 ± 3.16 mm2 VS 71.43 ± 3.35 mm2, P < 0.001) and a larger contralateral facetectomy angle (63.95 ± 3.34° vs 57.80 ± 3.43°, P < 0.001) compared with patients in the UE-ULBD group. There were no statistical differences in the incidence of postoperative complications between the two groups. ConclusionBoth the BE-ULBD and the UE-ULBD yielded clinical improvement in terms of pain and stenosis symptoms. The BE-ULBD technique has the advantages of the shorter operation time, larger DSCSA expansion and larger contralateral facetectomy angle.

In retrospective, the gentle learning curve of unilateral laminectomy promotes favorable clinical outcomes

BackgroundThe learning curve in implementing a new surgical procedure is often time-consuming and potentially comes with the additional risk of injury associated with an unusual surgical procedure, which may harm the patient. AimEvaluate intraoperative burden and neurologic recovery of spinal tumor resection following unilateral laminectomy procedures. MethodsMedical records of patients undergoing surgery for intradural spinal tumors from January 2015 to June 2020 were retrospectively reviewed. Preoperative and postoperative data were collected from medical records and interviews. The intraoperative burden was assessed by duration of surgery, estimated intraoperative blood loss (EIBL), and postoperative leukocyte count. Short-term and long-term outcomes were recorded. Data analysis was performed using descriptive statistics and Fisher's exact test. The neurological recovery rate is calculated by the Hirabayashi method, where a 75–100% score indicates an excellent neurological recovery. ResultsTwenty-six records were included in this study. The mean duration of surgery was 180 (120–540) minutes, the mean EIBL was 175 (50 – 1,200) mL, and mean increase in postoperative leukocyte count was 5,670 (2,210 – 13,250) cells/mL, and the mean LOS was 6.5 (4 – 42) days. In 20 of 26 (76.9%) patients, gross total resection was achieved. An excellent neurological recovery rate was achieved in 81% of patients. ConclusionUnilateral laminectomy procedures are adaptable without additional disadvantages, resulting in satisfactory clinical results.

358 Biomechanical Analysis of the Structural Stability of the Lumbar Spine Following the Extent of Endoscopic Lumbar Foraminotomy and Laminotomy: A Finite Element Analysis

INTRODUCTION: Facetectomy as the standard surgical option performed to relieve the patient's symptoms. Recently, endoscopic lumbar foraminotomy shows an alternative to secure space for the spinal nerve to pass through the foramen. However, the biomechanical research on the postoperative structure stability of the spine after endoscopic surgery remains unknown. METHODS: Six types of models were constructed following the graded removal L4 left side of the superior articular process with or without lamina: Type 1: intact model; Type 2: foraminotomy of left-superior dorsal corner of the superior articular process; Type 3: extended foraminotomy of left superior ventral side of the superior articular process; Type 4: left side total facetectomy; Type 5: left side facetectomy and unilateral laminectomy; Type 6: left side facetectomy and laminectomy. RESULTS: From the changes of experiment data in our finite element analysis of simulated endoscopic surgery, the extent of facet removal increases, the mobility and stress distribution of the surgical segment increases. In all loading conditions, the increase rate of the range of motion was the highest in Type 6 in L3-L4 compared to the intact model. The measured increase rate of von Mises s tresses was highest in left lateral bending in types 5 and 6. Furthermore, under other modes of movement, there was no peak von Mises stress differences on Type 1 to Type 4. CONCLUSIONS: In symptomatic lumbar foraminal stenosis, the impact of endoscopic foraminotomy on the stability may be less than those of total facetectomy. There is no significant difference between the standard and extended endoscopic foraminotomy on stability of the lumbar spine.

Intraoperative Spinal Cord Stimulation Mitigates Central Sensitization After Spine Surgery in Mice.

Double-blinded, prospective laboratory animal study. To examine whether intraoperative spinal cord stimulation (SCS) inhibits the development of spine surgery-induced hypersensitivity. Managing postoperative pain after spine surgery is challenging, and as many as 40% of patients may develop failed back surgery syndrome. Although SCS has been shown to effectively reduce chronic pain symptoms, it is unknown whether intraoperative SCS can mitigate the development of central sensitization that causes postoperative pain hypersensitivity and potentially leads to failed back surgery syndrome after spine surgery. Mice were randomly stratified into three experimental groups: (1) sham surgery, (2) laminectomy alone, and (3) laminectomy plus SCS. Secondary mechanical hypersensitivity was measured in hind paws using von Frey assay one day before and at predetermined times after surgery. In addition, we also performed a conflict avoidance test to capture the affective-motivational domain of pain at selected time points postlaminectomy. Mice that underwent unilateral T13 laminectomy developed mechanical hypersensitivity in both hind paws. Intraoperative SCS applied to the exposed side of the dorsal spinal cord significantly inhibited the development of hind paw mechanical hypersensitivity on the SCS-applied side. Sham surgery did not produce any obvious secondary mechanical hypersensitivity in the hind paws. These results demonstrate that spine surgery for unilateral laminectomy induces central sensitization that results in postoperative pain hypersensitivity. Intraoperative SCS after laminectomy may be able to mitigate the development of this hypersensitivity in appropriately selected cases.

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.

Learning curve for microscopic unilateral laminectomy for bilateral decompression surgery using the cumulative summation test for learning curve.

A retrospective observational study The purpose of this study was to characterize the learning curve for a single level unilateral laminectomy and bilateral decompression in lumbar spinal stenosis using a learning curve cumulative summation test. Unilateral laminectomy and bilateral decompression for lumbar spinal stenosis proposes a potential benefit with minimizing surgery-related instability compared to traditional bilateral laminectomy, by preserving posterior stabilizing structures and contralateral facet joint and neural arch. Due to a narrow surgical corridor, it is considered to exhibit a steep learning curve as other types of minimally invasive procedures. However, there are few reports available regarding learning curve of unilateral laminectomy and bilateral decompression. The learning curve of a single surgeon performing single level unilateral laminectomy and bilateral decompression was assessed using learning curve cumulative summation test analysis. The surgeon had minimal experience in open decompressive laminectomy but no previous experience in unilateral laminectomy and bilateral decompression. Procedure success was defined as an operation time less than 75 minutes. Surgery related complications were recorded. Total 194 consecutive patients, who underwent primary single level unilateral laminectomy and bilateral decompression by a single spine surgeon, were included. The mean operative time for unilateral laminectomy and bilateral decompression was 64.6 ± 23.6 minutes. The mean operative time in the early learning period (≤29th case) was 80.6 ± 20.9 minutes, and that in the late learning period (after 29th case) was 61.8 ± 22.7 minutes, respectively. The overall complication rate was 13.9%. Majority of complications occurred in the early learning period. The learning curve cumulative summation test signaled competency for unilateral laminectomy and bilateral decompression at the 29th operation, indicating that the surgeon reached the competent level. In addition, based on the cumulative summation test, the surgeon seemed to maintain his competency for the procedure. This study showed that surgical experience reduced the operation time and surgery related complications. For inexperienced surgeon to achieve an acceptable outcome in unilateral laminectomy and bilateral decompression, minimum 30 cases of unilateral laminectomy and bilateral decompression are required to reach competent level of surgery.

Efficacy and Safety of Microscopic Bilateral Decompression with Unilateral Laminectomy in Geriatric Lumbar Spinal Stenosis Surgery

Efficacy and Safety of Microscopic Bilateral Decompression with Unilateral Laminectomy in Geriatric Lumbar Spinal Stenosis Surgery

A meta-analysis of clinical effects of microscopic unilateral laminectomy bilateral decompression (ULBD) versus biportal endoscopic ULBD for lumbar canal stenosis.

OsbjectiveSeveral studies have shown that both microscopic unilateral laminotomy bilateral decompression (ULBD) and unilateral biportal endoscopic (UBE) ULBD are effective for treating lumbar canal stenosis (LCS). However, there are different viewpoints as to which surgical technique is superior. Therefore, this meta-analysis investigated the clinical efficacy and side effects of microscopic ULBD and UBE ULBD for treating LCS.MethodsTo identify relevant studies describing the clinical outcomes and complication rates of microscopic ULBD and UBE ULBD for LCS, several databases were systematically searched in the Internet. The visual analog scale score for back and leg pain and the Oswestry Disability Index were used to assess clinical outcomes. Furthermore, data about perioperative outcomes and complications were documented.ResultsIn total, six studies with 450 participants were included in this meta-analysis. The UBE ULBD was found to be superior to microscopic ULBD in terms of efficacy against early postoperative back and leg pain. However, there was no significant difference between the two procedures in terms of final clinical outcomes and complications. In addition, compared with microscopic ULBD, UBE ULBD was associated with a significant reduction in the length of hospital stay and C-reactive protein levels 2 days after surgery.ConclusionUBE ULBD and microscopic ULBD for the treatment of LCS were similar in terms of final clinical outcomes and complications. However, UBE ULBD has several advantages over microscopic ULBE, including a shorter hospital stay and faster alleviation of postoperative back and leg pain.

Change in sagittal alignment after decompression alone in patients with lumbar spinal stenosis without significant deformity: a prospective cohort study.

The authors' objective was to investigate whether sagittal balance improves in patients with spinal stenosis after decompression alone. This prospective longitudinal cohort study compared preoperative and 6-month postoperative 36-inch full-length radiographs in patients aged older than 60 years. Patients underwent decompression alone for central lumbar spinal stenosis with either a minimally invasive bilateral laminotomy for central decompression, unilateral laminectomy as an over-the-top procedure for bilateral decompression, or traditional wide laminectomy with removal of the spinous processes on both sides. The following radiographic parameters were measured: sagittal vertical axis (SVA), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), PI-LL mismatch, coronal Cobb angle, and sacral slope (SS). Patient-reported outcome measures (PROMs) were collected, including scores on the Oswestry Disability Index (ODI), visual analog scale (VAS) for leg and back pain, and EQ-5D. Forty-five patients (24 males) with a mean ± SD age of 71.8 ± 5.6 years were included. Sagittal balance showed statistically significant improvement, with the mean SVA decreasing from 52.3 mm preoperatively to 33.9 mm postoperatively (p = 0.0001). The authors found an increase in LL, from mean -41.5° preoperatively to -43.9° postoperatively, but this was not statistically significant (p = 0.055). A statistically significant decrease in PI-LL mismatch from mean 8.4° preoperatively to 5.8° postoperatively was found (p = 0.002). All PROM scores showed significant improvement after spinal decompression surgery. The correlations between SVA and all PROMs were statistically significant at both preoperative and postoperative time points, although most correlations were weak except for those between preoperative SVA and ODI (r = 0.55) and between SVA and VAS for leg pain (r = 0.58). Sagittal balance and PROMs show improvement at short-term follow-up evaluations in patients who have undergone decompression alone for lumbar spinal stenosis.

A comparative study of one-stage posterior unilateral limited laminectomy vs. bilateral laminectomy debridement and bone grafting fusion combined with internal fixation for the treatment of aged patients with single-segment spinal tuberculosis

Study designThis is a retrospective study.BackgroundTo assess and compare the clinical outcomes of posterior unilateral limited laminectomy (ULL) or bilateral laminectomy (BL) debridement and bone grafting fusion combined with internal fixation among aged patients with single-segment thoracic and lumbar tuberculosis (SST/LTB).Materials and methodsWe performed a retrospective study on aged patients (age > 65 years old) with SST/LTB from January 2010 to October 2018. We reviewed 36 aged patients who were treated with BL and 31 aged patients treated with ULL. All participants had undergone and finished a three-year follow-up. The outcomes were evaluated by the improvement of neurological function, correction Cobb angle, bone fusion time, and back pain, as well as operative time, blood loss, hospital stay, and postoperative complications.ResultsThe operative time, blood loss volume, and incidence of complications in group B were significantly less than those in group A (P < 0.01). The postoperative kyphotic angle in both groups was reduced significantly compared to the preoperative status (P < 0.01). The percentage of neurological improvement was 92.9% in group A and 90.9% in group B. All patients achieved solid bone fusion after surgery. At three-year follow-up, the angle loss in group B was significantly less than that in group A (P < 0.01); Furthermore, patients in group B had a lower average visual analog scale score of back pain and Oswestry Disability Index score than patients in group A (P < 0.05).ConclusionsFor aged patients with SST/LTB, ULL is a safer and more effective surgical treatment than BL.

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.

Endoscopic Spine Surgery of the Cervicothoracic Spine: A Review of Current Applications.

Endoscopic spine surgery in the cervicothoracic spine is generating continued interest in a rapidly evolving field. The authors present 4 techniques for fully endoscopic cervical spine surgery: (1) posterior cervical unilateral laminectomy and bilateral decompression, (2) posterior cervical foraminotomy, (3) anterior cervical discectomy, and (4) anterior transcorporal discectomy. Two techniques for fully endoscopic thoracic spine surgery are also presented: (1) posterior thoracic unilateral laminectomy and bilateral decompression and (2) transforaminal thoracic endoscopic discectomy and foraminotomy. We describe 6 different surgical approaches and review the relevant literature about each technique. The clinical application of endoscopic spine surgery techniques has evolved over the past 40 years. Recent data suggest comparable outcomes to other procedures and perhaps fewer complications and quicker recovery when these techniques are used in the cervical and thoracic spine. Significant variability exists in these approaches depending on the goal of canal decompression, root decompression, and the site of the pathology. Each endoscopic approach in the cervicothoracic spine has its technical nuances, outcomes, advantages, and disadvantages, making fully endoscopic cervicothoracic spine surgery an exciting and growing field.

Postoperative spinal epidural hematoma in a biportal endoscopic spine surgery.

Biportal endoscopic spine surgery (BESS) is extending its application to most kind of spine surgeries. Postoperative spinal epidural hematoma (POSEH) is one of the major concerns of this emerging technique. Through this study we aim to investigate the incidence of POSEH in BESS comparing to a conventional spine surgery (CSS).The patients who underwent a non-fusion decompressive spine surgery due to degenerative lumbar spinal stenosis (LSS) or herniated lumbar disc (HLD) or both between January 2015 and March 2019 were reviewed retrospectively. The incidence of clinical POSEH that demanded a revision surgery for hematoma evacuation was compared between CSS and BESS. As a second endpoint, the morphometric degree of POSEH was compared between the two groups. The maximal compression of cauda equina by POSEH was measured by 4 grade scale at the T2 axial image and the neurological state was evaluated by 5 grade scale. The indication of hematoma evacuation was more than hG3 with more than nG1. As a subgroup analysis, risk factors of POSEH in BESS were investigated.The 2 groups were homogenous in age, sex, number and level of operated segments. There was significant difference in the incidence of symptomatic POSEH as 2/142 (1.4%) in CSS and 8/95 (8.4%) in BESS (P = .016). The radiological thecal sac compression by hematoma was hG1 65 (61.3%), hG2 35 (33.0%), hG3 5 (4.7%), hG4 1 (0.9%) cases in CSS and hG1 33 (39.8%), hG2 25 (30.1%), hG3 22 (26.5%), hG4 3 cases (3.6%) in BESS. The difference was significant (P < .001). In BESS subgroup analysis, the risk factor of high grade POSEH was bilateral laminectomy (OR = 8.893, P = .023).The incidence of clinical and morphometric POSEH was higher in BESS. In BESS, POSEH developed more frequently in bilateral laminectomy than unilateral laminectomy.

Effect of single-segment unilateral laminectomy and facetectomy on sheep lumbar spine stability: an in vitro biomechanical study

Effect of single-segment unilateral laminectomy and facetectomy on sheep lumbar spine stability: an in vitro biomechanical study