Clinical outcomes of microendoscopic decompressive laminotomy for degenerative lumbar spinal stenosis

Unilateral biportal endoscopic discectomy via translaminar approach for highly upward-migrated lumbar disc herniation: a technical note and preliminary treatment outcomes

STUDY DESIGN

A technical note and retrospective case series.

OBJECTIVE

Highly upward-migrated lumbar disc herniation (LDH) is challenging due to its problematic access and incomplete removal. The most used interlaminar approach may cause extensive bony destruction. We developed a novel translaminar approach using the unilateral portal endoscopic (UBE) technique, emphasizing effective neural decompression, and preserving the facet joint's integrity.

METHODS

This retrospective study included six patients receiving UBE translaminar discectomy for highly upward-migrated LDHs from May 2019 to June 2021. The migrated disc was removed through a small keyhole on the lamina of the cranial vertebra. The treatment results were evaluated by operation time, hospital stays, complications, visual analog scale (VAS), Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) score, and modified MacNab criteria.

RESULTS

The mean pre-operative VAS for back pain (5.0 ± 4.9), VAS for leg pain (9.2 ± 1.0), JOA score (10.7 ± 6.6), and ODI (75.7 ± 25.3) were significantly improved to 0.3 ± 0.5, 1.2 ± 1.5, 27.3 ± 1.8, 5.0 ± 11.3 respectively at the final follow-up. Five patients had excellent, and one patient had good outcomes according to the Modified MacNab criteria. The hospital stay was 2.7 ± 0.5 days. No complication was recorded. The MRI follow-up showed complete disc removal, except for one patient with an asymptomatic residual disc.

CONCLUSIONS

UBE translaminar discectomy is a safe and effective minimally invasive procedure for highly upward-migrated LDH with satisfactory treatment outcomes and nearly 100% facet joint preservation.

Decision-making Algorithm for the Surgical Treatment of Degenerative Lumbar Spondylolisthesis of L4/L5

STUDY DESIGN

A retrospective analysis of prospectively collected data.

OBJECTIVE

To report the decision-making process for decompression alone (DA) and decompression and fusion (DF) at a tertiary orthopedic center and compare the operative outcomes between both groups.

BACKGROUND

Controversy exists around the optimal operative treatment for DLS, either with DF or DA. Although previous studies tried to establish specific indications, clinical decision-making algorithms are needed.

MATERIALS AND METHODS

Patients undergoing spinal surgery for DLS at L4/5 were retrospectively analyzed. A survey of spine surgeons was performed to identify factors influencing surgical decision-making, and their association with the surgical procedure was tested in the clinical data set. We then developed a clinical score based on the statistical analysis and survey results. The predictive capability of the score was tested in the clinical data set with a receiver operating characteristic (ROC) analysis. To evaluate the clinical outcome, two years follow-up postoperative Oswestry Disability Index (ODI), postoperative low back pain (LBP) (Numeric Analog Scale), and patient satisfaction were compared between the DF and DA groups.

RESULTS

A total of 124 patients were included in the analysis; 66 received DF (53.2%) and 58 DA (46.8%). Both groups showed no significant differences in postoperative ODI, LBP, or satisfaction. The degree of spondylolisthesis, facet joint diastasis and effusion, sagittal disbalance, and severity of LBP were identified as the most important factors for deciding on DA or DF. The area under the curve of the decision-making score was 0.84. At a cutoff of three points indicating DF, the accuracy was 80.6%.

CONCLUSIONS

The two-year follow-up data showed that both groups showed similar improvement in ODI after both procedures, validating the respective decision. The developed score shows excellent predictive capabilities for the decision processes of different spine surgeons at a single tertiary center and highlights relevant clinical and radiographic parameters. Further studies are needed to assess the external applicability of these findings.

Early efficacy observation of the unilateral biportal endoscopic technique in the treatment of multi-level lumbar spinal stenosis

BACKGROUND

To explore the early curative effect of unilateral biportal endoscopy (UBE) in the treatment of multi-level lumbar spinal stenosis with the help of multiple small incisions.

METHODS

A retrospective analysis was performed on 26 patients with multi-level lumbar spinal stenosis treated by UBE in our hospital from August 1, 2021, to March 1, 2022. We collect patients' basic medical records and independently design surgical incisions. The visual analog score (VAS) and Oswestry Disability Index (ODI) were compared before surgery, 7 days after surgery and 6 months after surgery. Spinal canal diameters on CT were compared before surgery and 7 days after surgery. The modified MacNab standard was used to evaluate the efficacy satisfaction at 6 months after operation.

RESULTS

In this study, 26 patients were operated according to the predetermined surgical plan. The operative time was 145 ± 40.11 min, the intraoperative blood loss was 156.25 ± 44.32 ml, and the postoperative hospital stay was 4.79 ± 1.31 days. The VAS scores of postoperative lumbago and leg pain were lower than those before surgery (P < 0.05). The postoperative ODI score was significantly different from that before surgery (P < 0.05). The postoperative CT sagittal diameter was significantly different from that before surgery (P < 0.05). The curative effect of modified MacNab was 76.92% when followed up 7 days after surgery. The curative effect of modified MacNab was 92.31% when followed up 6 months after surgery, which was significantly improved compared with 7 days after surgery.

CONCLUSION

Under multiple small incision channels, UBE can effectively treat multi-level lumbar spinal stenosis, significantly relieve the clinical symptoms of patients, and significantly improve the quality of life of patients. It is a safe and feasible minimally invasive surgical treatment method for multi-level lumbar spinal stenosis.

The clinical effect of unilateral decompressive laminectomy plus fusion with unilateral biportal endoscopic technique for single level lumbar spinal stenosis

PURPOSE

This study aimed to compare and analyze the effectiveness of unilateral biportal endoscopic (UBE) decompressive laminectomy plus fusion and microscope-assisted open decompressive laminectomy plus fusion.

METHODS

A total of 143 patients with lumbar spinal stenosis were enrolled in this study between March 2020 and February 2021 with a minimum 2 years follow-up visit to our hospital. Sixty-five patients underwent the unilateral biportal endoscopic technique and were assigned to the UBE group, and the remaining 78 patients with microscope assistant were assigned to the Microscope group. The baseline characteristics, clinical outcomes, and radiological data were retrospectively collected and analyzed, as well as Clinical outcomes, radiological data and complications.

RESULTS

There were no significant differences between the two groups in terms of baseline characteristics (P > 0.05). The UBE group was demonstrated to be significantly superior in CRP, drainage, blood loss, treatment cost and Hospital stay than the Microscope group (P < 0.05), whereas a significant longer operation time was observed (P < 0.05). The VAS-B, ODI, and JOA-L scores of the UBE group at 1 year follow-up were significantly greater than those of the Microscope group (P < 0.05). Regarding radiological data, there were no significant differences in the section area of the spinal canal and fusion grade between the two groups (P > 0.05).

CONCLUSION

In view of the satisfactory clinical outcomes of patients and notable decompression at the stenosed segment, UBE is a feasible, minimally invasive technique for single level lumbar canal stenosis.

Preoperative factors affecting the two-year postoperative patient-reported outcome in single-level lumbar grade I degenerative spondylolisthesis

Background

The choice of operative method for lumbar spinal stenosis with Meyerding grade I degenerative spondylolisthesis remains controversial. The purpose of this study was to identify the preoperative factors affecting the 2-year postoperative patient-reported outcome in Meyerding grade I degenerative spondylolisthesis.

Methods

Seventy-two consecutive patients who had minimally invasive decompression alone (D group; 28) or with fusion (DF group; 44) were enrolled. The parameters investigated were the Japanese Orthopaedic Association back pain evaluation questionnaire as patient-reported assessment, and L4 slippage (L4S), lumbar lordosis (LL), and lumbar axis sacral distance (LASD) as an index of sagittal alignment for radiological evaluation. Data collected prospectively at 2 years postoperatively were examined by statistical analysis.

Results

Sixty-two cases (D group; 25, DF group; 37) were finally evaluated. In multiple logistic regression analysis, preoperative L4S and LASD were extracted as significant preoperative factors affecting the 2-year postoperative outcome. Patients with preoperative L4S of 6 mm or more have a lower rate of improvement in lumbar spine dysfunction due to low back pain (risk ratio=0.188, p=.043). Patients with a preoperative LASD of 30 mm or more have a higher rate of improvement in lumbar dysfunction due to low back pain (risk ratio=11.48, p=.021). The results of multiple logistic analysis by operative method showed that there was a higher rate of improvement in lumbar spine dysfunction due to low back pain in patients with preoperative LASD of 30 mm or more in DF group (risk ratio=172.028, p=.01).

Conclusions

Preoperative L4S and LASD were extracted as significant preoperative factors affecting patient-reported outcomes at 2 years postoperatively. Multiple logistic analyses by the operative method suggested that DF may be advantageous in improving lumbar dysfunction due to low back pain in patients with preoperative LASD of 30 mm or more.

Pin-assisted retraction technique in unilateral biportal endoscopic discectomy: a retrospective cohort study

OBJECTIVE

Unilateral biportal endoscopic (UBE) discectomy is a reliable endoscopic technique in the treatment of lumbar disc herniation. However, UBE discectomy involves a single-handed manipulation, which may compromise the utility of the procedure. The present study was performed to examine the efficacy and safety of a novel pin-assisted retraction technique.

METHODS

This single-center retrospective cohort study involved 57 consecutive patients who underwent UBE lumbar discectomy from July 2021 to May 2022. The patients were randomly divided into the pin-assisted UBE discectomy group (P-UBE group) and the traditional UBE discectomy group (T-UBE group). The patients' perioperative data, clinical outcomes, and radiologic outcomes were collected and compared between the two groups.

RESULTS

The operative time, intraoperative blood loss, endoscopic irrigation volume, and overall complication rate were significantly lower in the P-UBE group than in the T-UBE group. There were no significant differences in the clinical outcome data between the two groups.

CONCLUSION

P-UBE discectomy may have superior safety and efficacy over the traditional technique, and it has the potential to serve as an optional method in UBE lumbar surgery.

Indications for and Outcomes of Three Unilateral Biportal Endoscopic Approaches for the Decompression of Degenerative Lumbar Spinal Stenosis: A Systematic Review

Objective: In this systematic review, we summarized the indications for and outcomes of three main unilateral biportal endoscopic (UBE) approaches for the decompression of degenerative lumbar spinal stenosis (DLSS). Methods: A comprehensive search of the literature was performed using Ovid Embase, PubMed, Web of Science, and Ovid’s Cochrane Library. The following information was collected: surgical data; patients’ scores on the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Macnab criteria; and surgical complications. Results: In total, 23 articles comprising 7 retrospective comparative studies, 2 prospective comparative studies, 12 retrospectives case series, and 2 randomized controlled trials were selected for quantitative analysis. The interlaminar approach for central and bilateral lateral recess stenoses, contralateral approach for isolated lateral recess stenosis, and paraspinal approach for foraminal stenosis were used in 16, 2, and 4 studies, respectively. In one study, both interlaminar and contralateral approaches were used. L4-5 was the most common level decompressed using the interlaminar and contralateral approaches, whereas L5-S1 was the most common level decompressed using the paraspinal approach. All three approaches provided favorable clinical outcomes at the final follow-up, with considerable improvements in patients’ VAS scores for leg pain (63.6–73.5%) and ODI scores (67.2–71%). The overall complication rate was <6%. Conclusions: The three approaches of UBE surgery are effective and safe for the decompression of various types of DLSS. In the future, long-term prospective studies and randomized control trials are warranted to explore this new technique further and to compare it with conventional surgical techniques.

Complications of Unilateral Biportal Endoscopic Spinal Surgery for Lumbar Spinal Stenosis: A Meta-Analysis and Systematic Review

BACKGROUND

In recent years, unilateral biportal endoscopic spinal surgery has been used for the treatment of lumbar spinal stenosis with good results. Some investigators counted the total incidence of complications in unilateral biportal endoscopic surgery for lumbar spinal stenosis, but none have analyzed the incidence of specific complications. The present study further counted the incidence of specific complications and gave the possible causes of the complications.

METHODS

English databases including PubMed were searched to collect relevant literature on unilateral biportal endoscopic spinal surgery for lumbar spinal stenosis. The inquiry period is from January 1, 2015, to July 1, 2022. The literature was screened, information extracted, and risk of bias evaluated by the researchers, followed by Meta analysis using R4.2.1 and RStudio statistical software.

RESULTS

In total, we included 14 studies involving 707 patients. The included studies were retrospective case series, The results of the single-arm rate meta-analysis showed that the total complication rate of unilateral biportal endoscopic surgery treatment of lumbar spinal stenosis was 8.1% (95% confidence interval [CI] [0.060; 0.103]); of which, the highest incidence of dural tear was 4.5% (95% CI [0.030; 0.064]), the incidence of symptomatic postoperative spinal epidural hematoma was approximately 1.1% (95% CI [0.001; 0.027]), the incidence of incomplete decompression was 2.0% (95% CI [0.007; 0.038]), the incidence of transient palsy was 2.6% (95% CI [0.005; 0.057]).

CONCLUSIONS

The incidence of total complications of unilateral biportal endoscopic surgery for lumbar spinal stenosis was 8.1%, dural tear remained a major complication with an incidence of 4.5%, incomplete decompression was 2.0%, transient palsy was 2.6%, and, unexpectedly, symptomatic postoperative spinal epidural hematoma was only 1.1%.

Increased Surgical Experience in Microendoscopic Spinal Surgery Can Reduce Development of Postoperative Spinal Epidural Hematoma and Improve the Clinical Outcomes

No reports have previously evaluated the association between surgical technique and the incidence of postoperative spinal epidural hematoma (PSEH) following microendoscopic decompression surgery (MED). This study aimed to evaluate the association between the development of radiographic PSEH (rPSEH) following MED and microendoscopic surgical experience and postoperative clinical outcomes related to the quality of life (QoL). This retrospective cohort study included 3922 patients who had undergone MED performed by a single surgeon. rPSEH was defined as a hematoma that was identified via routine magnetic resonance images performed 3−4 days postoperatively. Patients were divided into rPSEH and control groups to identify the risk factor of rPSEH and assess clinical outcomes. In the multivariate analysis, age (p = 0.002), surgical experience (p = 0.003), surgical time (p = 0.038), multilevel decompression (p < 0.001), and diagnosis (p = 0.004) were identified as independent variables associated with rPSEH. Moreover, in mixed-effect models, the rPSEH group showed less improvement in Oswestry Disability Index (p = 0.014) than the control group. In conclusion, the surgical experience was identified as a risk factor for rPSEH that could lead to poor QoL. The sharing of microendoscopic surgical techniques among surgeons may reduce rPSEH incidence and improve patients’ QoL.

Microscopic Unilateral Approach for Bilateral Decompression of Lumbar Spinal Stenosis

BACKGROUND

This is a study based on single-surgeon data on spinal stenosis surgery via microscopic approach. The aim is to evaluate the effectiveness of the unilateral approach to bilateral decompression and the usage of Taylor retractors and brain spatula in patients with spinal stenosis.

METHODS

This is a retrospective study on bilateral decompression for lumbar spinal stenosis using a microscopic unilateral approach by a single surgeon, between April 2015 and March 2018. In total, 50 patients were operated due to single level lumbar spinal stenosis. All patients were evaluated by preoperative and postoperative plain radiographs and magnetic resonance (MR) images. Walking distance (WD), visual analog scale (VAS) for pain and Odom's criteria were evaluated for follow-up.

RESULTS

One level of the lumbar spine was surgically decompressed in all patients. The median age of patients was 64.6 (51- 82). Of the patients, 72% (36) were women, and 28% (14) were men. Most patients had refractory low back pain (96%) after conservative treatment. The stenotic levels of the cases were as follows: L3-4, 23(46%); L4-5, 24(48%); and L5-S1, 3 (6%). VAS scores decreased in all patients after surgery. According to Odom's criteria, an excellent or good score was found in 43 patients at the 12th follow-up examination. WDs increased up to 1000 meters for 41 patients.

CONCLUSION

The microscopic unilateral approach to bilateral decompression is an effective method for decompression in spinal stenosis. Via this approach, surgical trauma is reduced and surgically induced instability is avoided as much as possible.

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.

Long-Term Outcomes of Laminectomy in Lumbar Spinal Stenosis: A Systematic Review and Meta-Analysis

Objective Lumbar spinal stenosis (LSS) patients suffer from significant pain and disability. To assess long-term safety and efficacy of laminectomy in LSS patients, a systematic review and meta-analysis study was conducted.

Methods Literature review in MEDLINE, Embase, Scopus, Web of Science, and Cochrane Library databases was performed using a predefined search strategy. Articles were included if they met the following characteristics: human studies, LSS, and at least 5 years of follow-up. Outcome measures included patient satisfaction, pain, disability, claudication, reoperation rates, and complications.

Results Twelve articles met the eligibility criteria for our study. Overall, there was low-quality evidence that patients undergoing laminectomy, with at least 5 years of follow-up, have significantly more satisfaction, and less pain and disability, compared with the preoperative baseline. Assessment of neurogenic intermittent claudication showed significant improvement in walking abilities. We also reviewed the postoperative complication and adverse events in the included studies. After meta-analysis was performed, the reoperation rate was found to be 14% (95% confidence interval: 13–16%).

Conclusion Our study provides low-quality evidence suggesting that patients undergoing laminectomy for LSS have less disability and pain and can be more physically active postoperatively.

Thermal Dynamics of a Novel Radio-Frequency Device for Endoscopic Spine Surgery: An Experimental Model

STUDY DESIGN

Experimental study.

OBJECTIVE

In this study, the ambient temperature of a radiofrequency (RF) electrode tip was compared and analyzed in terms of products, mode, flow quantity, and flow rate.

SUMMARY OF BACKGROUND DATA

Endoscopic spine surgery is a widely used operation for degenerative lumbar stenosis and herniated lumbar disc. To perform endoscopic spine surgery, dedicated instruments like a RF generator and electrode are essential.

METHODS

An evaluation system capable of measuring temperature under equal conditions at a certain distance from the electrode tip was manufactured. The distance between the electrode tip and the temperature sensor was set to 1, 5, and 10 mm. The flow quantities of 0, 50, 100, and 150 mL/min and the flow rates of 0, 0.20, 0.53, and 0.80 m/s were compared and statistically analyzed.

RESULTS

The temperatures measured in the experiments conducted on the four combinations of RF device showed similar values, and showed differences according to the characteristics of each mode of the RF. As the distance between the electrode tip and the temperature sensor increased, the temperature decreased, and as flow quantity or flow rate increased, the temperature decreased. The maximum temperatures differed significantly according to flow quantity, between flow quantities of 0 and 100 mL/min (P  = 0.03) and between 0 and 150 mL/min (P ≤ 0.01). The maximum temperatures also differed significantly between the flow rate of 0 m/s, and the flow rates of 0.20, 0.53, and 0.80 m/s, with P ≤ 0.01 in all three comparisons.

CONCLUSION

This is the first study in which we made a customized RF temperature evaluation system and verified the temperature changes in various environments. When irrigation was performed, we could confirm that the maximum temperature was less than 60°C. Irrigation is considered essential in endoscopic spine surgery.

LEVEL OF EVIDENCE

3.

Adjacent Segment Degeneration after Short-Segment Lateral Lumbar Interbody Fusion (LLIF)

Purpose

To investigate the influence on the adjacent segment degeneration (ASD) of short-segment lateral lumbar interbody fusion (LLIF) at 2 years postoperatively.

Methods

Ninety-seven consecutive patients who underwent one- or two-level LLIF were included from two institutions. We diagnosed radiographical adjacent segment degeneration with the appearance of adjacent spondylolisthesis (>3 mm) or deterioration of adjacent disk height (>3 mm) on plain radiographs or decrease of the intervertebral angle (>5 degrees). The differences between the two groups with and without radiographical ASD were investigated using univariate and multivariate analyses to determine the risk factors for ASD. The variables included extent of adjacent decompression, posterior fixation method (open method or percutaneous method), and facet violation on postoperative CT.

Results

In total, 19 patients (19.6%) were diagnosed as radiographical ASD 2 years after surgery. Univariate analysis showed that the ASD (+) group had a high frequency of adjacent decompression (21.1 vs. 3.8%, p = 0.035) compared with the ASD (-) group. There were no differences between the two groups in posterior fusion method (percutaneous method 42.1 vs. 57.7%, p = 0.221) or facet joint violation (15.8 vs. 14.1%, p = 0.860). The multivariate analysis found adjacent intervertebral decompression to be a risk factor for ASD 2 years after surgery (odds ratio: 9.95; 95% confidence interval: 1.2–82.1).

Conclusions

Adjacent intervertebral decompression was considered to be a potential risk factor for the development of ASD after spinal fusion with LLIF.

Microendoscopic Lumbar Posterior Decompression Surgery for Lumbar Spinal Stenosis: Literature Review

Lumbar spinal stenosis (LSS) is a common disease in the elderly, mostly due to degenerative changes in the lumbar spinal complex. Decompression surgery is the standard surgical treatment for LSS. Classically, total laminectomy—which involves resection of the spinous process, entire laminae and medial facet—has been the standard decompression technique; however, it can cause post-surgical instability. To overcome this disadvantage, various minimally invasive techniques that preserve the stabilization structures of the spine have been developed, and surgeons have begun to re-evaluate decompression surgery from the standpoint of reduced invasiveness and cost. More than two decades have passed since the introduction of microendoscopic spine surgery, and studies continue to shed light on its advantages and limitations as new knowledge becomes available. This article is a narrative review of the available literature, along with authors’ experience, regarding the indications, surgical techniques, clinical outcomes, and limitations/complications of microendoscopic decompression for LSS.

Revision surgery following minimally invasive decompression for lumbar spinal stenosis with and without stable degenerative spondylolisthesis: a 5- to 15-year reoperation survival analysis

OBJECTIVE

Minimally invasive decompression (MID) is an effective procedure for lumbar spinal stenosis (LSS). Long-term follow-up data on reoperation rates are lacking. The objective of this retrospective cohort study was to evaluate reoperation rates in patients with LSS who underwent MID, stratified for degenerative lumbar spondylolisthesis (DLS), with a follow-up between 5 and 15 years.

METHODS

All consecutive patients with LSS who underwent MID between 2002 and 2011 were included. All patients had neurogenic claudication from central and/or lateral recess stenosis, without or with up to 25% of slippage (grade I spondylolisthesis), and no obvious dynamic instability on imaging (increase in spondylolisthesis by ≥ 5 mm demonstrated on supine-to-standing or flexion-extension imaging). Reoperation rates defined as any operation on the same or adjacent level were assessed. Revision decompression alone was considered if the aforementioned clinical and radiographic criteria were met; otherwise, patients underwent a minimally invasive posterior fusion.

RESULTS

A total of 246 patients (mean age 66 years) were included. Preoperative spondylolisthesis was present in 56.9%. The mean follow-up period was 8.2 years (range 5.0-14.9 years). The reoperation rates in patients with and without spondylolisthesis were 15.7% and 15.1%, respectively; fusion was required in 7.1% and 7.5%, with no significant difference (redecompression only, p = 0.954; fusion, p = 0.546). For decompression only, the mean times to reoperation were 3.9 years (95% CI 1.8-6.0 years) for patients with DLS and 2.8 years (95% CI 1.3-4.2 years) for patients without DLS; for fusion, the mean times to reoperation were 3.1 years (95% CI 1.0-5.3 years) and 3.1 years (95% CI 1.1-5.1 years), respectively.

CONCLUSIONS

In highly selected patients with stable DLS and leg-dominant pain from central or lateral recess stenosis, the long-term reoperation rate is similar between DLS and non-DLS patients undergoing MIS decompression.

Clinical Outcomes of Minimally Invasive Posterior Decompression for Lumbar Spinal Stenosis with Degenerative Spondylolisthesis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To compare the clinical outcomes 5 years after minimally invasive posterior decompression for lumber spinal stenosis (LSS) between patients with and without degenerative spondylolisthesis (DS).

SUMMARY OF BACKGROUND DATA

Indications for surgical procedures for patients with LSS and DS are still under investigation. Since minimally invasive surgery does not affect most anatomical structures, preoperative DS may not negatively affect the clinical outcomes of minimally invasive posterior decompression.

METHODS

Overall, 198 patients with LSS who underwent microendoscopic or microscopic decompression and were followed up for more than 5 years postoperatively were included in the present study. Patients who showed a segmental kyphosis >5° at the surgical level during flexion were treated with fusion surgery. However, other patients, including those with DS, were treated with posterior decompression. The patients were divided into two groups: the DS group included 82 patients with >3-mm slip and the non-DS group included 112 patients with ≤3-mm slip or without slip. A mixed-effects model adjusted for age and sex was used to compare the improvements in the visual analog scale score for low-back pain and the Japanese Orthopaedic Association score of the two groups. For subgroup analysis (n = 53), the changes in the preoperative physical component summary and the mental component summary of Short Form-36 of the two groups at 5 years after surgery were evaluated.

RESULTS

There was no significant difference in the improvement of preoperative low-back pain visual analog scale score and Japanese Orthopaedic Association score 5 years after surgery between the two groups. Subgroup analysis showed no significant difference between the two groups in the improvement of preoperative physical component summary and mental component summary 5 years after surgery.

CONCLUSION

After carefully eliminating patients with segmental instability, DS did not affect the clinical outcomes of minimally invasive decompression surgery.Level of Evidence: 3.

Ultrafast laser surgery probe with a calcium fluoride miniaturized objective for bone ablation

We present a miniaturized ultrafast laser surgery probe with improved miniaturized optics to deliver higher peak powers and enable higher surgical speeds than previously possible. A custom-built miniaturized CaF2 objective showed no evidence of the strong multiphoton absorption observed in our previous ZnS-based probe, enabling higher laser power delivery to the tissue surface for ablation. A Kagome fiber delivered ultrashort pulses from a high repetition rate fiber laser to the objective, producing a focal beam radius of 1.96 μm and covering a 90×90 μm2 scan area. The probe delivered the maximum available fiber laser power, providing fluences >6 J/cm2 at the tissue surface at 53% transmission efficiency. We characterized the probe's performance through a parametric ablation study on bovine cortical bone and defined optimal operating parameters for surgery using an experimental- and simulation-based approach. The entire opto-mechanical system, enclosed within a 5-mm diameter housing with a 2.6-mm diameter probe tip, achieved material removal rates >0.1 mm3/min, however removal rates were ultimately limited by the available laser power. Towards a next generation surgery probe, we simulated maximum material removal rates when using a higher power fiber laser and found that removal rates >2 mm3/min could be attained through appropriate selection of laser surgery parameters. With future development, the device presented here can serve as a precise surgical tool with clinically viable speeds for delicate applications such as spinal decompression surgeries.

Intraoperative disc level marking with needle: a technical note and prospective study on 30 patients

BACKGROUND

Wrong-level surgery is a rare but unresolved issue in spine surgery. Some proposed protocols with high success rates, but it remains a risk with potential complications for the patient. Surgical navigation offers more accurate surgery, without additional irradiation related to the imaging device, in order to optimize the surgical guidance.

METHODS

We describe our institutional technique with a needle placed under fluoroscopy at 3 cm from the incision line at the disc level to be operated, in order to guide the surgical approach; and we report a prospective evaluation of all patients during a six-month period operated by microdiscectomy for symptomatic lumbar discus hernia, whose hernia level was landmarked with this technique. We collected demographic, clinical-such as visual analog scale (VAS) of pain and Oswestry disability index (ODI) scores-operative and irradiation data for effective dose calculation.

RESULTS

Thirty patients were included in the study. No wrong-level procedure was performed. Mean time for landmarking was 2.22 [1-5] minutes. Average operative time was 54.5 [30-150] minutes. The effective dose related to the imaging device use was 0.032 (0.007-0.092) mSv. The effective dose was also correlated to body mass index and disc level (P=0.05). The operative duration, complication rate and postoperative VAS and ODI scores were similar to the current literature.

CONCLUSIONS

We advocate the use of percutaneous needle guidance, avoiding wrong-level microdiscectomy and helping the surgeon as a "navigation-like" device with minimal additional irradiation for the patient.

"A decade with micro-tubular decompression": Peri-operative complications and surgical outcomes in single and multilevel lumbar canal stenosis

PURPOSE

We present ten years experience with micro-tubular decompression (MTD) performed for single and multilevel lumbar canal stenosis (LCS) assessing the peri-operative complications and mid-term surgical outcome. The aims of this study were to review the incidence of peri-operative complications and classification of complications and define risk factors to prevent it while negotiating the learning curve.

METHODS

A retrospective review of prospectively collected data over a period of ten years involving 625 patients who underwent single/multilevel lumbar MTD. Peri-operative clinical-radiological parameters, post-operative complications, clinical outcome (VAS and ODI), and satisfactory outcomes in the form of Wang and Bohlmann's criteria were evaluated. The peri-operative complications were divided into five broad categories based on their time of occurrence, severity, and system affected. The comparison between the patients with and without complications was done to evaluate the causative risk factors.

RESULTS

The overall incidence of the peri-operative complication was 12.96% over ten years with higher rate (29.8%) during the initial three years of practice and lower rate (8.78%) in the last seven years. The most common peri-operative complications were urinary tract infections (UTI). The risk factors for complications with MTD revealed in statistical analysis were presence of one or more comorbidities, L4-L5 single-level stenosis, bilateral stenosis with ipsilateral and bilateral decompression done through unilateral approach, and multilevel MTD done through single incision for multilevel LCS. More than 95% patients operated with MTD showed excellent to good outcome as per the Wang and Bohlmann's criteria at the final follow-up.

CONCLUSION

This study represents 12.96% overall incidence of peri-operative complications with higher rate (29.8%) during the initial three years of practice and lower rate (8.78%) in the last seven years with MTD for single/multilevel LCS with. MTD is an effective procedure with substantial clinical benefits in the form of excellent to good clinico-radiological outcomes at two year follow-up. However, there is a learning curve associated with the adoption of the technique. The described classification for peri-operative complications is helpful to record, to evaluate, and to understand the aetiology and risk factors based on its duration of occurrence in the peri-operative period.

Microendoscope-Assisted Versus Open Posterior Lumbar Interbody Fusion for Lumbar Degenerative Disease: A Multicenter Retrospective Cohort Study

Background and objectives: Minimally invasive surgery has become popular for posterior lumbar interbody fusion (PLIF). Microendoscope-assisted PLIF (ME-PLIF) utilizes a microendoscope within a tubular retractor for PLIF procedures; however, there are no published reports that compare Microendoscope-assisted to open PLIF. Here we compare the surgical and clinical outcomes of ME-PLIF with those of open PLIF. Materials and Methods: A total of 155 consecutive patients who underwent single-level PLIF were registered prospectively. Of the 149 patients with a complete set of preoperative data, 72 patients underwent ME-PLIF (ME-group), and 77 underwent open PLIF (open-group). Clinical and radiographic findings collected one year after surgery were compared. Results: Of the 149 patients, 57 patients in ME-group and 58 patients in the open-group were available. The ME-PLIF procedure required a significantly shorter operating time and involved less intraoperative blood loss. Three patients in both groups reported dural tears as intraoperative complications. Three patients in ME-group experienced postoperative complications, compared to two patients in the open-group. The fusion rate in ME-group at one year was lower than that in the open group (p = 0.06). The proportion of patients who were satisfied was significantly higher in the ME-group (p = 0.02). Conclusions: ME-PLIF was associated with equivalent post-surgical outcomes and significantly higher rates of patient satisfaction than the traditional open PLIF procedure. However, the fusion rate after ME-PLIF tended to be lower than that after the traditional open method.

The short-term outcomes of minimally invasive decompression surgery in patients with lumbar ossification or calcification of the ligamentum flavum

OBJECTIVE

Although minimally invasive endoscopic surgery techniques are established standard treatment choices for various degenerative conditions of the lumbar spine, the surgical indications of such techniques for specific cases, such as segments with ossification of the ligamentum flavum (OLF) or calcification of the ligamentum flavum (CLF), remain under investigation. Therefore, the authors aimed to demonstrate the short-term outcomes of minimally invasive endoscopic surgery in patients with degenerative lumbar disease with CLF or OLF.

METHODS

This is a retrospective cohort study including consecutive patients who underwent microendoscopic posterior decompression at the authors' institution, where the presence of OLF and CLF did not influence the surgical indication. Fifty-nine patients with OLF and 39 patients with CLF on preoperative CT were identified from the database. Subsequently, two matched control groups (one each matched to the OLF and CLF groups) were created using propensity scores to adjust for age, sex, preoperative Japanese Orthopaedic Association (JOA) score and Oswestry Disability Index, and diagnosis. The background, surgical outcomes, and changes in clinical scores were compared between the matched groups. If there was a significant difference in the improvement of clinical scores, a multivariate linear regression model was applied.

RESULTS

On performing univariate analysis, patients with OLF were found to have a higher body mass index (Mann-Whitney U-test, p = 0.001), higher incidence of preoperative motor weakness (chi-square test, p = 0.019), longer operative time (Mann-Whitney U-test, p < 0.001), and lower improvement in the JOA score (mixed-effects model, p = 0.023) than the matched controls. On performing multivariate analysis, the presence of OLF was identified as an independent variable associated with a poor recovery rate based on the JOA score (multivariate linear regression, p < 0.001). In contrast, there were no significant differences between patients with CLF and their matched controls in terms of preoperative and surgical data and postoperative improvements in clinical scores.

CONCLUSIONS

Although the perioperative surgical outcomes, including the surgical complications, and the in-hospital period did not significantly differ, the short-term improvement in the JOA score was significantly lower in patients with degenerative lumbar disease accompanied by OLF than in the patients from the matched control group. In contrast, there were no significant differences in the short-term improvement in clinical scores and perioperative outcomes between patients with CLF and their matched control group. Thus, the surgical indications of minimally invasive posterior decompression for patients with CLF can be the same as those for patients without CLF; however, the indications for patients with OLF should be further investigated in future studies, including the other surgical methods.

Feasibility of Unilateral Approach for Bilateral Decompressive Endoscopic Spinal Surgery for Lumbar Stenosis to Improve Back and Leg Pain: A Consecutive Single-Center Series of 60 Patients

Introduction: Endoscopic surgery is one of the methods that achieve the goal of decompression while minimizing collateral tissue damage. Its efficacy and safety have been supported by numerous studies. There is a plethora of studies on lumbar stenosis regarding the outcomes and related issues in endoscopic spine surgery. However, few studies evaluated the outcome of the decompressive lumbar spine surgery. The present study aims to analyze the outcome of a unilateral approach to endoscopic surgery for lumbar stenosis using the visual analog scale (VAS), the Oswestry Disability Index (ODI), and MacNab's criteria.

Methods: This is a retrospective study (level IV) conducted between January 2009 and December 2013 on 60 patients who underwent endoscopic interlaminar decompressive spine surgery (Destandau method) for lumbar degenerative spinal stenosis in the Hospital Universiti Sains Malaysia. The clinical outcome was measured pre-operatively and post-operatively for VAS: for back and leg pain, motor and sensory grading, the ODI, and MacNab's criteria. A paired t-test was used for statistical analysis.

Results: The mean age of patients was 60.82 years comprising 23 males (38.3%) and 37 females (61.7%). The mean follow-up period was 30.1 months (range = 17.2–43 months). The mean operation time was 183.6 min (ranging from 124.8 to 242.4 min), and the mean blood loss was 150.18 mL (ranging from 30.82 to 269.54 mL). Post-operatively, mean hospital stay was 2.45 days (ranging from 1.34 to 3.56 days). The most frequently involved level was L4/L5 in 51 patients (52.6%), followed by L3/L4 in 19 patients (19.6%), L5/S1 in 24 patients (24.7%), and L2/L3 in three patients (3.1%). Improvement in the post-operative VAS for back and leg pain and the ODI for pre-operation and post-operation was statistically significant (p < 0.001). Conversely, the reduction in neurological status was statistically insignificant. Based on MacNab's criteria, 88.4% showed excellent to good outcomes.

Conclusion: To summarize, unilateral percutaneous endoscopic spine surgery to achieve the bilateral decompression in lumbar stenosis provides excellent yet safe and effective outcomes. It improves back and leg pain and patients' function significantly.

Degenerative Spondylolisthesis: When to Fuse and When Not to? A New Scoring System

STUDY DESIGN

A prospective cohort.

OBJECTIVE

The objective of this study was to develop a scoring system for lumbar degenerative spondylolisthesis (LDS) that would guide decision-making.

BACKGROUND

The management protocol for LDS has been under debate, with no guidelines. Most studies oversimplify LDS as a homogenous entity.

MATERIALS AND METHODS

A retrospective analysis of 131 patients who underwent surgery for LDS between July 2007 and October 2011 with a minimum follow-up of 3 years was carried out on the basis of clinical, radiologic, and technical factors. A scoring system was conceptualized. Clinical: back pain score-2, age younger than 70 years-1, high-demand activity-1. Radiologic: segmental kyphosis-1.5, segmental dynamic translation-1, disk height >50% of adjacent level-1, facet effusion-1, sagittal facet-orientation-1. Technical: feasibility to decompress without causing instability-1.5. Its reliability was ascertained by a univariate analysis. The benchmark was set at 5.5 according to the Youden Index. This was followed by a prospective study for reliability analysis between November 2011 and January 2017 of 52 patients who underwent stand-alone decompression in LDS with a minimum follow-up of 24 months. Outcomes were evaluated using the Oswestry Disability Index and the Visual Analog Scale. Interobserver variability was determined. None of the patients in the retrospective or prospective group had undergone any lumbar surgery previously.

RESULTS

The mean Oswestry Disability Index and Visual Analog Scale of both the groups in the retrospective and the stand-alone decompression groups in prospective studies showed significant improvement. The interobserver reliability was high, with a κ value of 0.847.

CONCLUSIONS

The proposed scoring system helps view LDS as a heterogenous condition and assists in tailoring treatment for individual patients. For a select subgroup of patients with LDS, minimally invasive decompression (unilateral laminotomy and bilateral decompression using a minimally invasive surgery tubular retractor system) without fusion is adequate.

LEVEL OF EVIDENCE

Level III.

Comparision of biportal endoscopic and microscopic decompression in treatment of lumbar spinal stenosis: A comparative study protocol

BACKGROUND

Microscopic bilateral decompression (MBD) has been suggested as an alternative to open laminectomy and fusion. Recently, percutaneous biportal endoscopic decompression (PBED) has begun to attract attention. The purpose of this retrospective study was to evaluate postoperative pain, functional disability, symptom reduction and satisfaction, and specific surgical parameters between the MBD and PBED techniques in patients with lumbar spinal stenosis (LSS).

METHODS

A retrospective review of LSS patients performed with MBD or PBED technique between May 2015 and June 2018 was conducted. Institutional review board approval in People's Hospital of Ningxia Hui Nationality Autonomous Region was obtained prior to conducting chart review and analysis. We received informed consent from all patients before surgery. The primary outcomes assessed were the preoperative to postoperative changes in leg/back pain and disability/function, patient satisfaction with the procedure, and postoperative quality of life. The secondary outcomes including duration of postoperative hospital stay, time to mobilization, postoperative analgesic use, complication rates, and baseline patient characteristics were prospectively collected.

RESULTS

The hypothesis was that the PBED technique would achieve better clinical outcomes as compared to the MBD technique in LSS.

Feasibility and Outcomes of Tubular Decompression in Extreme Stenosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

To report the feasibility, nuances, technical tips as well as outcomes of managing single-level grade D (extreme stenosis) and to compare the outcomes with nonextreme stenosis using the tubular retractor system.

SUMMARY OF BACKGROUND DATA

Minimally invasive decompression in extreme stenosis is a challenge due to technical difficulty, feasibility of adequate decompression, and a steep learning curve.

METHODS

Consecutive patients from January 2007 to January 2017 presenting with neurogenic claudication secondary to single-level spinal stenosis operated using tubular retractors were included in the study. The patients were divided into two groups; extreme-stenosis and nonextreme stenosis. The outcomes of surgery were evaluated and compared using visual analogue score (VAS) for leg and back pain, Oswestry disability index (ODI), and MacNab's criteria.

RESULTS

A total of 325 patients (out of 446 patients after excluding the multilevel cases) fulfilled the inclusion criteria. One hundred forty patients were cases of extreme stenosis and 185 were nonextreme stenosis. The mean VAS for back and leg pain for extreme stenosis improved from 3.23 ± 1.30 to 2.15 ± 0.91 and 7.33 ± 0.78 to 1.66 ± 1.03 respectively as compared with nonextreme stenosis where the mean VAS for back and leg pain improved from 3.01 ± 1.15 to 1.86 ± 1.10 and 6.57 ± 1.00 to 1.54 ± 1.12 respectively. The mean ODI changed from 66.47 ± 7.53 to 19.95 ± 2.90 in extreme stenosis as compared with nonextreme stenosis where mean ODI changed from 59.05 ± 5.08 to 19.88 ± 2.67. As per MacNab's criteria 102 (of 120 patients) and 139 (of 157 patients) reported excellent and good outcomes in extreme and nonextreme stenosis respectively.

CONCLUSION

Tubular decompression is feasible in patients with extreme-stenosis with no difference in the outcomes as well as complication rates when compared with a cohort of nonextreme stenosis.

LEVEL OF EVIDENCE

3.

Unilateral biportal endoscopic decompression for degenerative lumbar canal stenosis

Background

Unilateral biportal endoscopic (UBE) decompression is a minimally invasive (MI) approach to treat degenerative lumbar canal stenosis (DLCS). Decompression can be performed in a clear and magnified surgical field with proper control of normal saline inflow and outflow.

Methods

Clinical and radiographic data of 81 consecutive patients of DLCS treated between July 2018 and Feb 2019 using UBE techniques were reviewed. They were 38 males and 43 females with an average age of 70.2. Sixty-nine had pure canal stenosis and 12 patients had associated spondylolisthesis. Bilateral decompression via unilateral laminotomy was performed from the side on patients with more severe neurological symptoms. This is a retrospective study from chart review and image analysis. Therefore, we don't have formal ethical information for this study, and it is not mandatory in our hospital.

Results

At the final follow-up, the mean VAS for low back pain was improved from 4.3±3.0 to 1.2±1.0 and the VAS for leg symptoms was improved from 7.3±2.2 to 0.9±0.7. The mean JOA score and ODI was significantly improved from 13.3±7.9 to 25.3±5.0 and from 54.6±16.9 to 14.6±12.6, respectively. Modified Macnab criteria were excellent in 47 patients (58.0%), good in 29 (35.8%), fair in 5 (6.2%). The average hospital stay was 3.6±2.4 days. MRI before and after the operation showed the cross-sectional dural area (CSDA) was significantly increased from 71.4±36.5 to 177.3±59.2 mm², corresponding to a 201.9%±188.0% increase. The percentage of facet joint preservation was 84.2% on the approach side and 92.9% on the contralateral side. Complications included 4 dural tears, 1 transient motor weakness, 1 inadequate decompression, and 1 epidural hematoma.

Conclusions

With UBE techniques, decompression for DLCS can be performed safely and effectively. The soft tissue and facet joint destruction are minimized; therefore, it is possible to avoid spinal fusion as well as to preserve the segmental stability.

Clinical and radiological outcomes between biportal endoscopic decompression and microscopic decompression in lumbar spinal stenosis

BACKGROUND CONTEXT

Numerous minimal invasive techniques treating lumbar spinal stenosis have been introduced. Clinical results using biportal endoscopic spinal surgery has recently been introduced as a treatment option for lumbar spinal stenosis. The purpose of this study was to compare the clinical and radiologic outcome between microscopic unilateral laminotomy bilateral decompression and biportal endoscopic unilateral laminotomy bilateral decompression in patients with degenerative lumbar spinal stenosis.

METHOD

A total of 89 patients were evaluated for this study. Only single-level patients were enrolled for accurate comparison. Patients that underwent biportal endoscopic surgery were assigned to Group A, and patients that underwent microscopic surgery were designated Group B. Clinical outcomes were evaluated using modified Macnab criteria, Oswestry Disability Index, and Visual Analog Scale. Postoperative complications were checked until final follow up. Plain radiographs before and after surgery were compared to analyze the change of alignment.

RESULT

There was a significant difference between Group A and B in VAS of back on postoperative 2 months. Other clinical measurements except for postoperative 2 months VAS of back showed no significant difference. There were no significant differences between Group A and Group B regarding preoperative and postoperative radiological findings.

CONCLUSION

Two different decompression techniques preserve the spinal structure and exhibit a favorable clinical outcome and have the advantage of not causing postoperative instability in the short term follow up. Biportal endoscopic surgery may leads to less postoperative back pain than microscopic surgery, which may allow early ambulation and shorter hospitalization period.

Comparative Study Between Uniportal Full-Endoscopic Interlaminar and Tubular Approach in the Treatment of Lumbar Spinal Stenosis: A Pilot Study

STUDY DESIGN

Multicenter, prospective, randomized, and double-blinded study.

OBJECTIVES

To compare tubular and endoscopic interlaminar approach.

METHODS

Patients with lumbar spinal stenosis and neurogenic claudication of were randomized to tubular or endoscopic technique. Enrollment period was 12 months. Clinical follow up at 1, 3, 6 months after surgery with visual analogue scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) score. Radiologic evaluation with magnetic resonance pre- and postsurgery.

RESULTS

Twenty patients were enrolled: 10 in tubular approach (12 levels) and 10 in endoscopic approach (11 levels). The percentage of enlargement of the spinal canal was higher in endoscopic approach (202%) compared with tubular approach (189%) but was not statistically significant (P = .777). The enlargement of the dural sac was higher in endoscopic group (209%) compared with tubular group (203%) but no difference was found between the 2 groups (P = .628). A modest significant correlation was found between the percentage of spinal canal decompression and enlargement of the dural sac (r = 0.5, P = .023). Both groups reported a significant clinical improvement postsurgery. However, no significant association was found between the percentage of enlargement of the spinal canal or the dural sac and clinical improvement as determined by scales scores. Endoscopic group had lower intrasurgical bleeding (P < .001) and lower disability at 6 months of follow-up than tubular group (p=0.037).

CONCLUSIONS

In the treatment of lumbar spinal stenosis, endoscopic technique allows similar decompression of the spinal canal and the dural sac, lower intrasurgical bleeding, similar symptoms improvement, and lower disability at 6 months of follow-up, as compared with the tubular technique.

Ipsilateral Pedicle Stress Fracture After Endoscopic Foraminal Decompression for Patient with Isthmic Spondylolisthesis

BACKGROUND

Minimally invasive endoscopic spine surgery is useful for the treatment of various spinal conditions. Although surgery-related complications such as dural injury, exiting nerve root injury, incomplete decompression, and hematoma have been reported, there are few reports of late complications after endoscopic surgery.

CASE DESCRIPTION

A 51-year-old man complained of radiating pain to the right leg. The patient underwent endoscopic foraminal decompression under the diagnosis of foraminal stenosis with isthmic type spondylolisthesis (L5-S1). The lower extremity radiating pain was improved after surgery. Six weeks after surgery, the patient's symptoms recurred. The patient experienced a sudden onset of severe low back pain, which was aggravated by any motion of the lumbar spine. Computed tomography scan and magnetic resonance imaging revealed a fracture line with a sclerotic margin at the base of the right pedicle at the L5 level. Because the symptoms significantly interfered with his normal activities of daily living, the patient was treated with a total laminectomy, followed by posterior instrumented fusion. As the indication for endoscopic spinal surgery is widening, endoscopic decompression surgery is being performed for patients with low-grade lumbar spondylolisthesis, regardless of the presence of advanced spinal instability. However, endoscopic decompression surgery may cause damage to the posterior facet joint, which may have worsened the instability and lead to late complications such as progression of spondylolisthesis and pedicle stress fracture.

CONCLUSIONS

The surgeon should carefully review risk factors such as isthmic type spondylolisthesis before planning spine surgery and minimize facet joint damage during endoscopic decompression.

Are There Differences Between Patients with Extreme Stenosis and Non-extreme Stenosis in Terms of Pain, Function or Complications After Spinal Decompression Using a Tubular Retractor System?

BACKGROUND

Micro-tubular decompression in extreme lumbar spinal stenosis is challenging because it is technically difficult to achieve adequate decompression. Whether the results of micro-tubular decompression related to pain, function, and complications in lumbar spinal stenosis of the extreme and non-extreme varieties are different has not yet been conclusively established.

QUESTIONS/PURPOSES

Are there differences between patients with extreme stenosis and non-extreme stenosis in terms of (1) VAS back or leg pain, (2) Oswestry Disability Index (ODI), or (3) complications when they were treated with spinal decompression using a tubular retractor system?

METHODS

Between January 2007 and January 2017, one surgeon performed 325 single-level lumbar micro-tubular decompressions without fusion. Of those, 43% (140 of 325) had extreme stenosis (defined as the absence of cerebrospinal fluid signal and a grey homogeneous dural sac with unrecognizable rootlets and posterior epidural fat in T2 weighted axial MRI image) and the rest had non-extreme stenosis. During this time, we used tubular retractors for these procedures in patients with simple lumbar spinal stenosis who had persistent symptoms despite conservative treatment for neurogenic claudication. No alternate form of decompression was performed in the study period. Patients with complex lumbar spinal stenosis associated with a deformity or instability who were treated with instrumented fusion were excluded. A total of 14% (20 of 140) patients in the extreme stenosis group and 15% (28 of 185) patients in the non-extreme stenosis group were lost to follow-up before 2 years; the remaining 120 patients with extreme stenosis and 157 patients with non-extreme stenosis were analyzed at a mean follow-up of 33 ± 5 months in this retrospective, comparative study. The groups were not different at baseline in terms of preoperative VAS score for back pain, age, gender, BMI or the percentage who had diabetes or who smoked. However, patients with extreme stenosis had higher preoperative ODI scores and higher preoperative VAS score for leg pain compared with the non-extreme group. There was a higher proportion of men in the non-extreme stenosis group (56% [104 of 185] versus 50% [71 of 140]; p = 0.324). Study endpoints were VAS score for leg and back pain, ODI, and complications, all of which were ascertained by chart review. With the numbers available, we could detect with 80% power at p < 0.05 a difference of 0.93 cm of 10 cm on a 10-cm VAS scale for VAS leg pain; a difference of 1.00 cm of 10 cm on a 10-cm VAS scale for VAS back pain and a difference of 2.12 cm of 100 cm on a 100-cm ODI scale.

RESULTS

In terms of pain, both groups improved after surgery, but there was no between-group difference in terms of the VAS scores at the most recent follow-up. VAS back pain improved from a mean of 3 ± 1 to 2 ± 1 in the extreme stenosis group and from 3 ± 1 to 1 ± 1 in the non-extreme stenosis group (p = 0.904); VAS leg pain improved from 7 ± 1 to 1 ± 1 versus 6 ± 1 to 1 ± 1, respectively (p = 0.537). ODI scores likewise improved in both groups, with no between-group difference in the ODI scores at latest follow-up (66 ± 7 to 19 ± 2 in the extreme stenosis group versus 59 ± 5 to 19 ± 2 in the non-extreme stenosis group (p = 0.237). Complications in the group with extreme stenosis occurred in six patients (incidental dural tears in two patients, urinary retention in three patients, and Syndrome of Inappropriate Anti Diuretic Hormone secretion (SIADH) in one patient); complications in the non-extreme stenosis occurred in two patients (incidental dural tears in two patients).

CONCLUSIONS

The results in terms of improvement in VAS for leg and back pain and ODI scores were not different between patients with extreme and non-extreme stenosis. Micro-tubular decompression can be thus considered an alternative for patients with extreme stenosis. Future studies, ideally multicentre, comparative trials, are needed to confirm our preliminary results.

LEVEL OF EVIDENCE LEVEL

III, therapeutic study.

Decompression Surgery versus Interspinous Devices for Lumbar Spinal Stenosis: A Systematic Review of the Literature

In this retrospective review study, the authors systematically reviewed the literature to elucidate the efficacy and complications associated with decompression and interspinous devices (ISDs) used in surgeries for lumbar spinal stenosis (LSS). LSS is a debilitating condition that affects the lumbar spinal cord and spinal nerve roots. However, a comprehensive report on the relative efficacy and complication rate of ISDs as they compare to traditional decompression procedures is currently lacking. The PubMed database was queried to identify clinical studies that exclusively investigated decompression, those that exclusively investigated ISDs, and those that compared decompression with ISDs. Only prospective cohort studies, case series, and randomized controlled trials that evaluated outcomes using the Visual Analog Scale (VAS), Oswestry Disability Index, or Japanese Orthopedic Association scores were included. A random-effects model was established to assess the difference between preoperative and the 1–2-year postoperative VAS scores between ISD surgery and lumbar decompression. This study included 40 papers that matched our criteria. Twenty-five decompression-exclusive clinical trials with 3,386 patients and a mean age of 68.7 years (range, 31–88 years) reported a 2.2% incidence rate of dural tears and a 2.6% incidence rate of postoperative infections. Eight ISD-exclusive clinical trials with 1,496 patients and a mean age of 65.1 (range, 19–89 years) reported a 5.3% incidence rate of postoperative leg pain and a 3.7% incidence rate of spinous process fractures. Seven studies that compared ISDs and decompression in 624 patients found a reoperation rate of 8.3% in ISD patients vs. 3.9% in decompression patients; they also reported dural tears in 0.32% of ISD patients vs. 5.2% in decompression patients. A meta-analysis of the randomized controlled trials found that the differences in preoperative and postoperative VAS scores between the two groups were not significant. Both decompression and ISD interventions are unique surgical interventions with different therapeutic efficacies and complications. The collected studies do not consistently demonstrate superiority of either procedure over the other but understanding the differences between the two techniques can help tailor treatment regimens for patients with LSS.

A protective method to reduce radiation exposure to the surgeon during endoscopic lumbar spine surgery

BACKGROUND

Endoscopic lumbar spine surgery is a minimally invasive technique that requires intraoperative fluoroscopic imaging. Fluoroscopy is a source of ionizing radiation, and exposure of the surgeon to this radiation has a risk for radiation-induced morbidities. To reduce this radiation exposure, we developed a protective method that can be used during endoscopic lumbar spine surgery. The purpose of the study was to determine the effectiveness of this method.

METHODS

A prospective interventional study was performed, in which the primary outcome was radiation exposure to the surgeon [Sievert (Sv)] per case. This was measured using a radiation badge at the levels of the neck, chest, and abdomen on the surface of a protector for the surgeon in 18 endoscopic lumbar spine surgeries, including 9 each with the radiation protection method and the conventional method. Data were also collected for age, gender, body mass index, operative side, and total fluoroscopy time. Primary outcomes were compared in cases that used the radiation protection method and the conventional method.

RESULTS

The mean radiation exposures to the surgeon at the neck, chest, and abdomen were 1.0, 0.8 and 0.7 µSv, respectively, using the radiation protection method, and 3.2, 10.8, and 10.2 µSv, respectively, using the conventional method. The differences in exposure at all three points were significant (P=0.013, P<0.001, P<0.001, respectively).

CONCLUSIONS

These results show the effectiveness of the radiation protection method developed to reduce exposure of the surgeon to radiation during endoscopic lumbar spine surgery.

[Minimally invasive decompression techniques for spinal cord stenosis]

BACKGROUND

Lumbar spinal canal stenosis is frequently found among elderly patients and significantly limits their quality of life. Non-surgical therapy is an initial treatment option; however, it does not eliminate the underlying pathology. Surgical decompression of the spinal canal has now become the treatment of choice.

OBJECTIVE

Minimalization of surgical approach strategies with maintaining sufficient decompression of the spinal canal and avoiding disadvantages of macrosurgical techniques, monolateral paravertebral approach with bilateral intraspinal decompression, specific surgical techniques.

MATERIALS AND METHODS

Minimally invasive decompression techniques using a microscope or an endoscope are presented and different surgical strategies depending on both the extent (mono-, bi-, and multisegmental) and the location of the stenosis (intraspinal central, lateral recess, foraminal) are described.

RESULTS

Minimally invasive microscopic or endoscopic decompression procedures enable sufficient widening of the spinal canal. Disadvantages of macrosurgical procedures (e. g., postoperative instability) can be avoided. The complication spectrum overlaps partially with that of macrosurgical interventions, albeit with significantly less marked severity. Subjective patient outcome is clearly improved.

CONCLUSIONS

Referring to modern minimally invasive decompression procedures, surgery of lumbar spinal canal stenosis represents a rational and logical treatment alternative, since causal treatment of the pathology is only possible with surgery.

Percutaneous Unilateral Biportal Endoscopic Spine Surgery Using a 30-Degree Arthroscope in Patients With Severe Lumbar Spinal Stenosis: A Technical Note

BACKGROUND

Unilateral biportal endoscopic surgery (UBESS) for severe lumbar central canal stenosis (LCCS) remains challenging.

OBJECTIVE

To describe the use of UBESS with a 30-degree arthroscope in patients with severe LCCS.

MATERIALS AND METHODS

Working and viewing portals were created in each unilateral paravertebral area at the target interlaminar level. After ensuring the visual field with a 30-degree arthroscope, effective tissue removal was possible through safe access to the bilateral hypertrophic yellow ligament with minimal osteotomy. The authors evaluated 58 patients and analyzed the clinical outcomes using the visual analog scale, Macnab criteria, and self-predicted walking distance.

RESULTS

The visual analog scale scores for low back and leg pains decreased from 7.1 to 1.9 and from 7.9 to 1.6, respectively, at 18 months after the procedure. According to the Macnab criteria, "excellent," "good," and "fair" results were obtained in 51.7%, 41.4%, and 6.9% subjects, respectively. Before surgery, the subjects could walk a mean of 305.8±468.1 m. After surgery, 43.1% of the patients could walk for >1 hour, whereas the remaining patients could walk 1521.8±1831.1 m.

CONCLUSION

UBESS using a 30-degree arthroscope can be an efficient and safe intervention in patients with severe LCCS.

Unilateral Laminotomy with Bilateral Decompression: A Case Series Studying One- and Two-Year Outcomes with Predictors of Minimal Clinical Improvement

OBJECTIVE

To assess factors that may predict failure to improve at 12 and 24 months after unilateral laminotomy with bilateral decompression (ULBD) for the management of lumbar spinal stenosis.

METHODS

A database of 255 patients who underwent microdecompression surgery by a single orthopedic spine surgeon between 2014 and 2018 was queried. Patients who underwent primary single-level ULBD of the lumbar spine were included. Visual analog scale (VAS) for back pain and leg pain and Oswestry Disability Index (ODI) results were collected preoperatively and at 12 and 24 months postoperatively. Demographic, radiographic, and operative factors were assessed for associations with failure to improve. Clinically important improvement was defined as reaching or surpassing the previously established minimum clinically important difference for ODI (12.8) and not requiring revision.

RESULTS

A total of 68 patients were included. Compared with preoperative values for back pain, leg pain, and ODI (7.32, 7.53, and 51.22, respectively), there were significant improvements on follow-up at 12 months (2.89, 2.23, and 22.40, respectively; P < 0.001) and 24 months (2.80, 2.11, 20.32, respectively; P < 0.001). Based on the defined criteria, 50 patients showed clinically important improvement after ULBD. Of the 18 patients who failed to improve, 12 required revision. Independent predictors of failure to improve included female sex (adjusted odds ratio, 5.06; 95% confidence interval, 1.49-21.12; P = 0.014) and current smoker status (adjusted odds ratio, 5.39; 95% confidence interval, 1.39-23.97; P = 0.018).

CONCLUSIONS

ULBD for the management of lumbar spinal stenosis leads to clinically important improvement that is maintained over a 24-month follow-up period. Female sex and tobacco smoking are associated with poorer outcomes.

Changes of balance control in individuals with lumbar degenerative spine disease after lumbar surgery: a longitudinal study

BACKGROUND CONTEXT

Lumbar degenerative spine disease (DSD) with neurological symptoms is the most common indication requiring lumbar surgery when nonoperative treatment is not effective. Individuals with lumbar DSD have sensory, proprioception, and musculoskeletal system alterations, which may result in balance impairment. However, evidence regarding balance recovery in individuals with lumbar DSD after lumbar surgery is limited.

PURPOSE

To evaluate balance control, pain, and functional activities in individuals with lumbar DSD after lumbar surgery.

STUDY DESIGN/SETTING

A prospective study with a cross-sectional control group.

PATIENT SAMPLE

Seventy individuals with lumbar DSD (DSD group) and 30 age-matched healthy adults (control group) were recruited. Participants in the DSD group were diagnosed by a neurological surgeon and received lumbar surgery according to relevant imaging findings and neurological symptoms.

OUTCOME MEASURES

Clinical assessments, including a visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the Roland-Morris Disability Questionnaire (RMDQ), were performed in the DSD group only. Balance control was assessed in all participants using the root mean square (RMS) distance of the center of pressure (COP) in anteroposterior and mediolateral directions.

METHODS

All participants were instructed to stand in natural stance and Romberg stance with eyes open and eyes closed on a force platform for 35 seconds, respectively. The assessments were performed in the DSD group at four time points: preoperative phase (baseline), 3 months, 6 months, and 12 months postoperatively. In the age-matched healthy control group, only one assessment on the recruitment day was performed.

RESULTS

The VAS, ODI, and RMDQ scores of the DSD group significantly improved after lumbar surgery (p<.001). The RMS distance of COP in the DSD group significantly decreased after lumbar surgery (p<.017) compared with baseline in most of the testing conditions. However, the RMS distance of the COP in the DSD group after surgery was significantly greater than in the healthy control group (p<.05), especially 6 months and 12 months postoperatively.

CONCLUSIONS

Balance control, pain, and functional activities of individuals with lumbar DSD showed improvement after lumbar surgery. However, balance control in individuals with lumbar DSD was still less stable than in age-matched healthy adults from 6 to 12 months after surgery. Therefore, individuals with lumbar DSD require fall prevention programs after lumbar surgery, including balance assessments and postoperative balance training.

A reproducible and reliable localization technique for lumbar spine surgery that minimizes unintended-level exposure and wrong-level surgery

BACKGROUND CONTEXT

Exposure of unintended levels (defined as a spinal segment outside the intended surgical levels) is unnecessary and potentially adds to operative time and patient morbidity. Wrong-level surgery (defined as decompression, instrumentation, or fusion of a spinal segment not part of the intended surgical procedure) clearly adds to morbidity as well as putting the surgeon at medicolegal risk.

PURPOSE

To describe a localization technique for posterior lumbar spine surgery to minimize both unintended-level exposure and wrong-level surgery.

STUDY DESIGN

Consecutive case series.

PATIENT SAMPLE

One thousand nine hundred and eighty-six consecutive posterior lumbar operations performed from January 2010 to January 2017 using this technique were reviewed.

OUTCOME MEASURES

The primary outcome measure was the incidence of unintended-level exposure and wrong-level surgery.

METHODS

This localization technique was consistently used for determination of skin incision, soft tissue dissection, and identification of spinal levels for all patients undergoing posterior lumbar surgery during the time interval noted. Two spinal needles are inserted under sterile technique 3cm lateral to the midline before incision at the approximate cranial and caudal aspects of the anticipated incision based on external landmarks. A cross-table lateral X-ray before incision is obtained and the actual incision is adjusted based on the location of the spinal needles. Once dissection is carried down to the facet capsules, spinal needles are then placed in adjacent facets, and a second cross-table lateral film is obtained to confirm appropriate levels. A retrospective review of all posterior lumbar cases was performed to determine the incidence of unintended-level exposure and wrong-level surgery using this technique.

RESULTS

There were no wrong-level surgeries during this time period. There were six (0.30%) cases of unintended-level exposure.

CONCLUSIONS

The technique described provides surgeons with a reliable, accurate, and easily reproducible method for localizing surgical levels during posterior lumbar spine surgery while minimizing exposure of uninvolved areas. This technique offers distinct advantages over previously proposed protocols and may lead to a widely accepted system for intraoperative spinal level identification.

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.

Endoscopic Lumbar Surgery: The State of the Art in 2019

This study was aimed to provide a brief historical perspective to facilitate appreciation of current techniques, describe outcomes of endoscopic lumbar surgery relative to those of existing techniques, and identify topics in need of study and future directions for the field of endoscopic lumbar surgery. Using the PubMed database, a comprehensive search was conducted to identify peer-reviewed English language articles pertaining to endoscopic lumbar surgery. Lack of focus on pertinent techniques or lack of outcome measures constituted exclusion criteria. A majority of included articles were published from 2015–2019. A context with which to appreciate the application of endoscopic lumbar techniques is established. An abundance of case series and several recent comparison studies have documented the benefits and potential pitfalls of these methods in the past two decades. The advantages of endoscopic lumbar spine surgery are widely touted to include reduced perioperative morbidity, including blood loss, operative time and immediate postoperative recovery, minimal structural trauma resulting from surgery, generally positive patient report outcome scores and the potential to contain costs. Additional high-quality research assessing outcomes of endoscopic lumbar surgery are certainly needed and currently expected given the rapid expansion of the field in recent years.

Step-by-Step Sublaminar Approach With a Newly-Designed Spinal Endoscope for Unilateral-Approach Bilateral Decompression in Spinal Stenosis

OBJECTIVE

Spinal stenosis is increasingly common due to population aging. In elderly patients with lumbar central canal stenosis (LCCS), minimizing muscle damage and bone resection is particularly important. We performed a step-by-step operation with a newly designed spinal endoscope to obtain adequate decompression in patients with spinal stenosis.

METHODS

From April 2015 to August 2016, 78 patients (48 males, 30 females) with LCCS (91 segments) underwent endoscopic decompression using a newly designed endoscope system. The inclusion criteria were: (1) neurogenic intermittent claudication with or without radiculopathy, (2) LCCS, and (3) having exhausted conservative treatment (>3 months). The exclusion criteria were: (1) >10° of instability, (2) spondylolisthesis grade II or greater according to the Meyerding criteria, (3) foraminal stenosis, (4) vascular intermittent claudication, (5) infection, and (6) stenosis combined with malignancy. We performed a step-by-step procedure using a newly designed endoscope system for unilateral-approach bilateral decompression. We used the same incision for 2-3 segments, only moving the skin.

RESULTS

The mean follow-up was 2.3±1.3 years. Excellent or good results were found according to the MacNab criteria in 85.9% of cases (67 of 78). The visual analogue scale, Japanese Orthopedic Association score, and Oswestry Disability Index showed significant decreases at 1 month, persisting until the 2-year follow-up. Dural tear occurred in 4 cases (5.1%), and patch repair was performed under endoscopy. No patients experienced aggravated instability requiring surgery.

CONCLUSION

We obtained good results with endoscopic decompression surgery using a newly designed instrument that minimized muscle and bone damage in elderly patients with spinal stenosis.

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.

Intra-operative imaging for spinal level localisation in lumbar surgery

Study Design: Retrospective review of the practice of 3 surgeons in a single centre during a 1-year period. Objective: We aimed to investigate our adherence to the Society of British Neurological Surgeons (SBNS) guidelines regarding intra-operative imaging during lumbar surgery and to determine if this has any impact on length of surgery or complications rates, in particular rates of wrong-level surgery. Background: The SBNS recommends three x-rays for intra-operative spinal localisation - one prior to incision, the second after exposure of the laminae and before the commencement of decompression, and the third at the end of the operation to confirm the adequacy of decompression. At our centre, surgeon A performs x-rays 1 and 3 routinely, and x-ray 2 in cases where the anatomy is uncertain, surgeon B performs x-ray 2 only, and the practice of surgeon C varies depending on the complexity of cases. Method: We reviewed the surgical logbooks of 3 consultant neurosurgeons in our centre for the 1-year period between October 2015 and October 2016. Our study included 301 patients who had undergone lumbar decompression or lumbar discectomy during this period. Results: There were no cases of wrong-level surgery. The incorrect spinal level was initially exposed in 13 cases (4.3%). 10 of these had x-ray 2 only, 1 had x-ray 1, 1 had x-rays 1 and 2, and 1 had all 3 x-rays. Surgeon B performed 8 of these cases, four were performed by surgeon C, and 1 by surgeon A. The median duration of surgery was 80 minutes for lumbar decompression and 67.5 minutes for lumbar discectomy. The median duration of surgery in patients in whom the wrong level was initially exposed was 85 minutes for lumbar decompression and 80 minutes for lumbar discectomy. Conclusion: Performance of the 3 recommended x-rays may increase the identification of wrong-level exposures before the commencement of decompression and may reduce the length of surgery.

Microendoscopic Decompression for Lumbar Spinal Stenosis With Degenerative Spondylolisthesis: The Influence of Spondylolisthesis Stage (Disc Height and Static and Dynamic Translation) on Clinical Outcomes

STUDY DESIGN

This study was a retrospective subgroup analysis of prospective cohort data.

OBJECTIVE

The main objectives of this study were to develop a classification of degenerative spondylolisthesis (DS) and concurrent lumbar spinal stenosis (LSS) based on pathologic stage, and to determine how these subtypes of DS affect outcomes for minimally invasive (MIS) decompression SUMMARY OF BACKGROUND DATA:: DS with LSS is a common clinical scenario, yet there is no consensus on optimal treatment. Natural history of DS is described as early degenerative damage, followed by instability, and eventual restabilization via spondylotic changes. MIS decompression surgery has become increasingly popular, but the effect of DS subtypes on clinical outcomes after MIS decompression is unknown.

PATIENTS AND METHODS

From 2008 to 2013, all patients who underwent microendoscopic laminotomy for single-level LSS with DS were included. In total, 218 patients (91 male, 127 female individuals) were reviewed. DS pathologic staging was defined as early, advanced, or end stage, based on percent slippage (10% slippage), degree of dynamic instability (3 mm), and disc height. The following variables were evaluated preoperatively and >2 years postoperatively and compared among groups: Japanese Orthopaedic Association (JOA) score, JOA recovery rate, and Visual Analog Scale low back pain.

RESULTS

In total, 173 patients were included in final analysis. Final follow-up period was 2.3 years. Average JOA recovery rate was 63.8%. There were no significant differences in JOA recovery and Visual Analog Scale among 3 DS stages (P>0.05). In total, 9.8% of patients required additional spine surgery, with 5% requiring subsequent fusion. All patients who required subsequent fusion were in the advanced stage DS group.

CONCLUSIONS

Microendoscopic decompression is an effective treatment for patients with DS and concurrent LSS, with only 5% of patients requiring subsequent fusion at over 2-year follow-up, and another 5% requiring revision or adjacent segment decompression. The advanced stage DS group, indicating a >10% anterolisthesis and/or >3 mm of dynamic instability, was more likely to require additional surgery.

Transforaminal Percutaneous Endoscopic Lumbar Decompression by Using Rigid Bendable Burr for Lumbar Lateral Recess Stenosis: Technique and Clinical Outcome

Background

Open laminectomy has been regarded as the standard surgical procedure for lumbar lateral recess stenosis during the last decades. Although percutaneous endoscopic lumbar decompression has led to successful results comparable with open decompression, its application in LSS with is still challenging and technically demanding. Here, we report the surgical procedure and preliminary clinical outcomes of transforaminal percutaneous endoscopic lumbar decompression (PELD) by using flexible burr for lumbar lateral recess stenosis.

Method

A retrospective study was performed for the patients with lumbar lateral recess stenosis receiving PELD by using flexible burr. The indications of surgery were moderate to severe stenosis, persistent neurological symptoms, and failure of conservative treatment. The patients with mechanical back pain, more than grade I spondylolisthesis, or radiographic signs of instability were not included. Before the operation, the transforaminal epidural lidocaine injections were carried out to make the diagnosis more precise and accurate. Radiologic findings were investigated, and visual analog scale (VAS) for back and leg pain, Oswestry Disability Index, and modified Macnab criteria were analyzed at the different time of preoperation, postoperation, 3 months, 6 months, and 12 months.

Results

The follow-up period was 12 months. The mean VAS scores for back and leg pain immediately improved from 7.9 ± 1.2 to 2.8± 1.3, 2.4 ± 1.0, and 2.3 ± 1.0, respectively. The mean visual analog scale scores (VAS) for back pain and leg pain were significantly improved after PELD. The preoperative ODI dropped from 69.1 ± 7.3 to 25.9 ± 8.7, 25.0± 6.9, and 24.7 ± 6.4, respectively. The final outcome was excellent in 39.6%, good in 47.9%, fair in 8.3%, and poor in 4.17%. 87.5% of excellent-to-good ratio was achieved on the basis of Macnab criteria at postoperative 12 months. The complications were limited to transient postoperative dysesthesia (one case), temporary pain aggravation (six cases), and neck pain during the operation (one case).

Conclusion

This observation suggests that the clinical outcomes of PELD for lateral recess stenosis were excellent or showed good results. This minimally invasive technique would be helpful in choosing a surgical method for lateral recess stenosis.

In-hospital complication rate following microendoscopic versus open lumbar laminectomy: a propensity score-matched analysis

BACKGROUND CONTEXT

The incidence of postoperative complications after microendoscopic laminectomy (MEL) has not been compared with that after open laminectomy in a large study, so it is not clear whether MEL is a safer procedure.

PURPOSE

The objective of this study was to compare postoperative morbidity and mortality following lumbar laminectomy between patients treated with MEL and with open laminectomy.

STUDY DESIGN

This is a retrospective cohort study with propensity score-matched analysis.

PATIENT SAMPLE

Data of patients who underwent elective spinal surgery between July 2010 and March 2013 were extracted from the Diagnosis Procedure Combination database, a nationwide inpatient database in Japan.

OUTCOME MEASURES

Clinical outcomes included length of hospital stay, occurrence of major complications (cardiac events, respiratory complications, pulmonary embolism, stroke, and acute renal failure), surgical site infection (SSI), postoperative delirium, and in-hospital death.

MATERIALS AND METHODS

Propensity score matching was performed to adjust for measured confounding factors, including patient age, sex, Charlson Comorbidity Index, body mass index, smoking status, blood transfusion, duration of anesthesia, number of operated disc levels, and type of hospital and hospital volumes. The clinical outcomes of one-to-one propensity-matched pairs of the MEL and the open laminectomy groups were compared.

RESULTS

Of 23,317 patients identified in the database, 1,536 underwent MEL (6.6%). By one-to-one propensity score matching, 1,536 pairs were selected. The distributions of patient backgrounds were closely balanced between the MEL and the open laminectomy groups. An analysis of 1,536 pairs revealed that there was a significantly lower incidence of major postoperative complications in those who underwent MEL (1.0% vs. 2.8% for open laminectomy, risk difference 1.8%, 95% confidence interval [CI] 0.9%-2.9%), SSI (0.5% vs. 1.6% for open laminectomy, risk difference 1.1%, 95% CI 0.4%-1.9%), and postoperative delirium (1.1% vs. 2.3% for open laminectomy, risk difference1.2%, 95% CI 0.3%-2.1%). The length of hospital stay was significantly shorter in those treated with MEL (12 days vs. 16 days for open laminectomy, p<.001). There was no significant difference in in-hospital mortality between the groups.

CONCLUSIONS

Patients who underwent MEL were significantly less likely to experience major postoperative complications and were less likely to develop SSI and postoperative delirium than those who underwent open laminectomy.

Comparison of minimally invasive decompression and combined minimally invasive decompression and fusion in patients with degenerative spondylolisthesis with instability

Posterior lumbar interbody fusion with cortical bone trajectory (CBT-PLIF) is a form of minimally invasive decompression and fusion, whereas microendoscopic laminotomy (MEL) is a form of minimally invasive decompression surgery. No study has compared the clinical outcomes of the two methods for patients who have degenerative spondylolisthesis (DS) with instability. In this study, CBT-PLIF and MEL were both offered to 64 patients who met the inclusion criteria. Each patient then selected his or her preferred treatment. Twenty patients received CBT-PLIF. They were matched to 30 of the 44 patients receiving MEL based on age, sex, disease duration, and surgical levels. The 20 patients with CBT-PLIF formed the CBT group and the 30 matched patients with MEL formed the MEL group. At 2 years of follow-up, Japanese Orthopaedic Association scores improved to 72.6% and 70.5% in the CBT and MEL groups, respectively. The difference in scores was not statistically significant. Further, improvements in visual analogue scale scores for back and leg symptom did not differ significantly between the two groups. Regarding complications, 1 CBT-group patient (5%) had adjacent-segment degeneration and 7 MEL-group patients (23%) had same-segment degeneration. Three CBT-group patients (15%) and 5 MEL-group patients (16%) required reoperation within the follow-up period. In summary, among patients who had DS with instability, MEL and CBT-PLIF offered comparable clinical outcomes at 2 years of follow-up. Although the rate of segmental degeneration was relatively high in the MEL group, both groups had similar reoperation rates.

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.

Clinical Outcome of Muscle-Preserving Interlaminar Decompression (MILD) for Lumbar Spinal Canal Stenosis: Minimum 5-Year Follow-Up Study

Introduction

Favorable short-term outcomes have been reported following muscle-preserving interlaminar decompression (MILD), a less invasive decompression surgery for lumbar spinal canal stenosis (LSCS). However, there are no reports of mid- to long-term outcomes. The purpose of this study was to evaluate the clinical outcomes five or more years after treatment of LSCS with MILD.

Methods

Subjects were 84 cases with LSCS (44 males; mean age, 68.7 years) examined five or more years after MILD. All patients had leg pain symptoms, with claudication and/or radicular pain. The patients were divided into three groups depending on the spinal deformity: 44 cases were without deformity (N group); 20 had degenerative spondylolisthesis (DS group); and 20 had degenerative scoliosis (DLS group). The clinical evaluation was performed using Japanese Orthopedic Association (JOA) scores, and revision surgeries were examined. Changes in lumbar alignment and stability were evaluated using plain radiographs.

Results

The overall JOA score recovery rate was 65.5% at final follow-up. The recovery rate was 69.5% in the N group, 65.2% in the DS group, and 54.0% in the DLS group, with the rate of the DLS group being significantly lower. There were 16 revision surgery cases (19.0%): seven in the N group (15.9%), three in the DS group (15.0%) and six in the DLS group (30.0%). There were no significant differences between pre- and postoperative total lumbar alignment or dynamic intervertebral angle in any of the groups, slip percentage in the DS group, or Cobb angle in the DLS group.

Conclusions

The mid-term clinical results of MILD were satisfactory, including in cases with deformity, and there was no major impact on radiologic lumbar alignment or stability. The clinical outcomes of cases with degenerative scoliosis were significantly less favorable and the revision rate was high. This should be taken into consideration when deciding on the surgical procedure.