Laminarthrectomy as a surgical approach for decompressing the spinal canal: assessment of preoperative versus postoperative dural sac cross-sectional areal (DSCSA)

Postoperative Dural Sac Cross-Sectional Area as an Association for Outcome After Surgery for Lumbar Spinal Stenosis: Clinical and Radiological Results From the NORDSTEN-Spinal Stenosis Trial

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

The aim was to investigate the association between postoperative dural sac cross-sectional area (DSCA) after decompressive surgery for lumbar spinal stenosis and clinical outcome. Furthermore, to investigate if there is a minimum threshold for how extensive a posterior decompression needs to be to achieve a satisfactory clinical result.

SUMMARY OF BACKGROUND DATA

There is limited scientific evidence for how extensive lumbar decompression needs to be to obtain a good clinical outcome in patients with symptomatic lumbar spinal stenosis.

MATERIALS AND METHODS

All patients were included in the Spinal Stenosis Trial of the NORwegian Degenerative spondylolisthesis and spinal STENosis (NORDSTEN)-study. The patients underwent decompression according to three different methods. DSCA measured on lumbar magnetic resonance imaging at baseline and at three months follow-up, and patient-reported outcome at baseline and at two-year follow-up were registered in a total of 393 patients. Mean age was 68 (SD: 8.3), proportion of males were 204/393 (52%), proportion of smokers were 80/393 (20%), and mean body mass index was 27.8 (SD: 4.2).The cohort was divided into quintiles based on the achieved DSCA postoperatively, the numeric, and relative increase of DSCA, and the association between the increase in DSCA and clinical outcome were evaluated.

RESULTS

At baseline, the mean DSCA in the whole cohort was 51.1 mm 2 (SD: 21.1). Postoperatively the area increased to a mean area of 120.6 mm 2 (SD: 46.9). The change in Oswestry disability index in the quintile with the largest DSCA was -22.0 (95% CI: -25.6 to -18), and in the quintile with the lowest DSCA the Oswestry disability index change was -18.9 (95% CI: -22.4 to -15.3). There were only minor differences in clinical improvement for patients in the different DSCA quintiles.

CONCLUSION

Less aggressive decompression performed similarly to wider decompression across multiple different patient-reported outcome measures at two years following surgery.

Comparison of the Tubular Approach and Uniportal Interlaminar Full-Endoscopic Approach in the Treatment of Lumbar Spinal Stenosis: Our 3-Year Results

BACKGROUND

To report the long-term results of patients with lumbar spinal stenosis (LSS), for whom we applied the tubular and endoscopic approaches and previously published the short-term results.

METHODS

A multicenter, prospective, randomized, double-blind study was carried out to evaluate 2 groups of patients with LSS who underwent microsurgery via a tubular retractor with a unilateral approach (T group) and bilateral spinal decompression using uniportal interlaminar endoscopic approaches (E group). Dural sac cross-sectional and spinal canal cross-sectional areas were measured with the patients' preoperative and postoperative magnetic resonance images. The visual analog scale, Oswestry Disability Index, and Japanese Orthopedic Association scores in the preoperative period and the first, second, and third years after surgery were evaluated.

RESULTS

Twenty patients met the inclusion criteria for the research (T group; n = 10, E group; n = 10). The groups' visual analog scale (respectively; P = 0.315, P = 0.529, and P = 0.853), Oswestry Disability Index (respectively; P = 0.529, P = 0.739, and P = 0.912), and Japanese Orthopedic Association (respectively; P = 0.436, P =0.853, and P = 0.684) scores from the first, second, and third postoperative years were quite good compared with the preoperative period, but there was no statistically significant difference. A significant difference was found in the E group, with less blood loss (P < 0.001).

CONCLUSIONS

The long-term results of the patients with LSS treated with tubular and endoscopic approaches were similar and very good. Bilateral decompression with minimally invasive spinal surgery methods can be completed with less tissue damage, complications, and blood loss with the unilateral approach.

Comparison of 3 Different Minimally Invasive Surgical Techniques for Lumbar Spinal Stenosis: A Randomized Clinical Trial

IMPORTANCE

Operations for lumbar spinal stenosis is the most often performed surgical procedure in the adult lumbar spine. This study reports the clinical outcome of the 3 most commonly used minimally invasive posterior decompression techniques.

OBJECTIVE

To compare the effectiveness of 3 minimally invasive posterior decompression techniques for lumbar spinal stenosis.

DESIGN, SETTING, AND PARTICIPANTS

This randomized clinical trial used a parallel group design and included patients with symptomatic and radiologically verified lumbar spinal stenosis without degenerative spondylolisthesis. Patients were enrolled between February 2014 and October 2018 at the orthopedic and neurosurgical departments of 16 Norwegian public hospitals. Statistical analysis was performed in the period from May to June 2021.

INTERVENTIONS

Patients were randomized to undergo 1 of the 3 minimally invasive posterior decompression techniques: unilateral laminotomy with crossover, bilateral laminotomy, and spinous process osteotomy.

MAIN OUTCOMES AND MEASURES

Primary outcome was change in disability measured with Oswestry Disability Index (ODI; range 0-100), presented as mean change from baseline to 2-year follow-up and proportions of patients classified as success (>30% reduction in ODI). Secondary outcomes were mean change in quality of life, disease-specific symptom severity measured with Zurich Claudication Questionnaire (ZCQ), back pain and leg pain on a 10-point numeric rating score (NRS), patient perceived benefit of the surgical procedure, duration of the surgical procedure, blood loss, perioperative complications, number of reoperations, and length of hospital stay.

RESULTS

In total, 437 patients were included with a median (IQR) age of 68 (62-73) years and 230 men (53%). Of the included patients, 146 were randomized to unilateral laminotomy with crossover, 142 to bilateral laminotomy, and 149 to spinous process osteotomy. The unilateral laminotomy with crossover group had a mean change of -17.9 ODI points (95% CI, -20.8 to -14.9), the bilateral laminotomy group had a mean change of -19.7 ODI points (95% CI, -22.7 to -16.8), and the spinous process osteotomy group had a mean change of -19.9 ODI points (95% CI, -22.8 to -17.0). There were no significant differences in primary or secondary outcomes among the 3 surgical procedures, except a longer duration of the surgical procedure in the bilateral laminotomy group.

CONCLUSIONS AND RELEVANCE

No differences in clinical outcomes or complication rates were found among the 3 minimally invasive posterior decompression techniques used to treat patients with lumbar spinal stenosis.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02007083.

Comparable increases in dural sac area after three different posterior decompression techniques for lumbar spinal stenosis: radiological results from a randomized controlled trial in the NORDSTEN study

PURPOSE

To investigate changes in dural sac area after three different posterior decompression techniques in patients undergoing surgery for lumbar spinal stenosis. Decompression of the nerve roots is the main surgical treatment for lumbar spinal stenosis. The aim of this study was to radiologically investigate three commonly used posterior decompression techniques.

METHODS

The present study reports data from one of two multicenter randomized trials included in the NORDSTEN study. In the present trial, involving 437 patients undergoing surgery, we report radiological results after three different midline retaining posterior decompression techniques: unilateral laminotomy with crossover (UL) (n = 146), bilateral laminotomy (BL) (n = 142) and spinous process osteotomy (SPO) (n = 149). MRI was performed before and three months after surgery. The increase in dural sac area and Schizas grade at the most stenotic level was evaluated. Three different predefined surgical indicators of substantial decompression were used: (1) postoperative dural sac area of > 100 mm², (2) increase in the dural sac area of at least 50% and (3) postoperative Schizas grade A or B.

RESULTS

No differences between the three surgical groups were found in the mean increase in dural sac area. Mean values were 66.0 (SD 41.5) mm² in the UL-group, 71.9 (SD 37.1) mm² in the BL-group and 68.1 (SD 41.0) mm² in the SPO-group (p = 0.49). No differences in the three predefined surgical outcomes between the three groups were found.

CONCLUSION

For patients with lumbar spinal stenosis, the three different surgical techniques provided the same increase in dural sac area.

CLINICAL TRIAL REGISTRATION

The study is registered at ClinicalTrials.gov reference on November 22th 2013 under the identifier NCT02007083.

Navigated minimally invasive unilateral laminotomy with crossover for intraoperative prediction of outcome in degenerative lumbar stenosis

BACKGROUND

Different surgical techniques have been described for treatment of degenerative lumbar stenosis (DLS). Only postoperative measures have been identified as predictors of efficacy of decompression. The objective of this study is to assess the role of navigated unilateral laminotomy with crossover to achieve and predict a satisfying decompression and outcome in DLS.

MATERIALS AND METHODS

We enrolled patients with DLS who underwent navigation-assisted unilateral laminotomy with crossover. The extent of decompression was evaluated during surgery using neuronavigation. The outcome was assessed through the Oswestry disability index (ODI) and visual analog scale (VAS) for leg pain. Outcome correlation with the extent of the intraoperative bone decompression was analyzed. Finally, the outcome, surgical time, and in-hospital length-of-stay were compared with a control group treated through standard unilateral laminotomy.

RESULTS

Twenty-five patients were treated using the navigated technique (Group A), 25 using the standard unilateral laminotomy (Group B). In Group A, a cut-off value ≥0.9 cm for bone decompression revealed to be an intraoperative predictor of good outcome, both regarding the ODI and VAS scores (P = 0.0005; P = 0.002). As compared with Group B, patients operated using the navigated technique showed similar operative times, in-hospital length-of-stay, ODI scores, but improved VAS scores for leg pain (P = 0.04).

CONCLUSIONS

The intraoperative navigated evaluation of the bone decompression could predict the outcome allowing satisfactory results in unilateral laminotomy for DLS. The navigated technique also could lead to an improved decompression of lateral recesses resulting in better control of leg pain as compared to standard unilateral laminotomy.

Study-protocol for a randomized controlled trial comparing clinical and radiological results after three different posterior decompression techniques for lumbar spinal stenosis: the Spinal Stenosis Trial (SST) (part of the NORDSTEN Study)

Background

There are several posterior decompression techniques for lumbar spinal stenosis (LSS). There is a trend towards performing less invasive surgical procedures, but no multicentre randomized controlled trials have evaluated the relative efficacy of these techniques at short and long-term.

Method/design

A multicentre randomized controlled trial [the Spinal Stenosis Trial (SST) (part of the NORDSTEN study)] including 465 patients aged 18–80 years with neurogenic claudication or radiating pain and MRI findings indicating lumbar spinal stenosis without spondylolisthesis is performed to compare three posterior decompression techniques: unilateral laminotomy with crossover, bilateral laminotomy and spinous process osteotomy. The primary outcome is change in Oswestry Disability Index (ODI 2 years postoperatively). Secondary outcomes are change in EQ-5D, Zurich Claudication Questionnaire, and Numeric Rating Scale for leg-pain and back-pain. Also recorded were Global Perceived Effect score, complications, length of hospital stay, reoperation rate 2 years postoperatively, difference in recurrence of symptoms or postoperative instability, and MRI change in the dural sac area. Further, a 5 and 10 years follow-up is planned with the same outcome measures.

Discussion

Newer and less invasive techniques are increasingly favoured in surgery for LSS. This trial will compare the clinical and radiological results of three different techniques, and may contribute to better clinical decision making in the surgical treatment of LSS.

Trial registration

ClinicalTrials.gov reference: NCT02007083 (November 22, 2013).

Does surgical technique influence clinical outcome after lumbar spinal stenosis decompression? A comparative effectiveness study from the Norwegian Registry for Spine Surgery

INTRODUCTION

The aim of this study was to compare the clinical outcome of spinal process osteotomy with two other midline-retaining methods, bilateral laminotomy and unilateral laminotomy with crossover, among patients undergoing surgery for lumbar spinal stenosis.

METHODS

This cohort study was based on data from the Norwegian Registry for Spine Surgery (NORspine). Patients were operated on between 2009 and 2013 at 31 Norwegian hospitals. The patients completed questionnaires at admission for surgery, and after 3 and 12 months. The Oswestry Disability Index (ODI) was the primary outcome. Secondary outcomes were duration of surgery and hospital stay, Numeric Rating Scale (NRS) for back pain and leg pain, and EQ-5D and EQ-VAS. The patients were classified into one of three treatment groups according to the surgery they had received, and a propensity score was utilized to minimize bias. The three treatment groups were divided into subgroups based on Propensity Scores, and the statistical analyses were performed with and within the Propensity Score stratified subgroups.

RESULTS

103 patients had spinal process osteotomy, 966 patients had bilateral laminotomy, and 462 patients had unilateral laminotomy with crossover. Baseline clinical scores were similar in the three groups. There were no differences in improvement after 3 and 12 months between treatment groups. At 12 months, mean ODI improvement was 15.2 (SD 16.7) after spinous process osteotomy, 16.9 (SD 17.0) after bilateral laminotomy, and 16.7 (SD 16.9) after unilateral laminotomy with crossover. There were no differences in the secondary clinical outcomes or complication rates. Mean duration of surgery was greatest for spinal process osteotomy (p < 0.05). Length of stay was 2.1 days (SD 2.1) in the bilateral laminotomy group, 3.5 (SD 2.4) days for unilateral laminotomy, and 6.9 days (SD 4.1) for spinous process osteotomy group (p < 0.05).

CONCLUSION

In a propensity scored matched cohort, there were no differences in the clinical outcome 12 months after surgery for lumbar spinal stenosis performed using the three different posterior decompression techniques. Bilateral laminotomy had shortest duration of surgery and shortest length of hospital stay. Surgical technique does not seem to affect clinical outcome after three different midline-retaining posterior decompression techniques.

Comparison of Outcomes of Percutaneous Endoscopic Lumbar Discectomy and Open Lumbar Microdiscectomy for Young Adults: A Retrospective Matched Cohort Study

OBJECTIVE

There have been only a few studies on surgical treatment of lumbar disc herniation (LDH) in young adults. In addition, previous studies do not provide detailed information on the surgical outcomes for young adults with LDH. The purpose of this study was to compare the outcome of transforaminal percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy for active, young adults (age 20-25 years).

METHODS

We performed retrospective chart and radiography. The patients were divided into 2 groups according to the surgical methods. Group A included the patients who underwent transforaminal PELD, and Group B included the patients who underwent open lumbar microdiscectomy for LDH at L4/5. After we matched for several factors, 32 young patients in group A and 34 young patients in group B were analyzed. We compared the outcomes between the 2 groups in terms of clinical, radiologic, perioperative outcomes, and surgery-related complications.

RESULTS

The clinical results for leg pain and radiologic results for decompression were the same in both groups. Most of complications in the PELD group occurred in the early phase. The recurrence rate and operation failure rate was no difference between the groups. The PELD brought significant advantages in the following areas: back pain, operation time, blood loss, hospital stay, and return-to-work.

CONCLUSIONS

Although a learning curve is needed in order to become familiar with PELD, PELD seemed to be a good choice for disc herniation in the lumbar spine for active, young adults.

Does daily tobacco smoking affect outcomes after microdecompression for degenerative central lumbar spinal stenosis? - A multicenter observational registry-based study

BACKGROUND

There are limited scientific data on the impact of smoking on patient-reported outcomes following minimally invasive spine surgery. The aim of this multicenter observational study was to examine the relationship between daily smoking and patient-reported outcome at 1 year using the Oswestry Disability Index (ODI) after microdecompression for single- and two-level central lumbar spinal stenosis (LSS). Secondary outcomes were the length of hospital stays, perioperative and postoperative complications.

METHOD

Data were collected through the Norwegian Registry for Spine Surgery (NORspine).

RESULTS

A total of 825 patients were included (619 nonsmokers and 206 smokers). For the whole patient population there was a significant difference between preoperative ODI and ODI at 1 year (17.3 points, 95% CI 15.93-18.67, p < 0.001). There was a significant difference in ODI change at 1 year between nonsmokers and smokers (4.2 points, 95% CI 0.98-7.34, p = 0.010). At 1 year 69.6% of nonsmokers had achieved a minimal clinically important difference (≥10 points ODI improvement) compared to 60.8% of smokers (p = 0.008). There was no difference between nonsmokers and smokers in the overall complication rate (11.6% vs. 9.2%, p = 0.34). There was no difference between nonsmokers and smokers in length of hospital stays for either single-level (2.3 vs. 2.2 days, p = 0.99) or two-level (3.1 vs. 2.3 days, p = 0.175) microdecompression. Smoking was identified as a negative predictor for ODI change in a multiple regression analysis (p = 0.001) CONCLUSIONS: Nonsmokers experienced a significantly larger improvement at 1 year following microdecompression for LSS compared to smokers. Smokers were less likely to achieve a minimal clinically important difference. However, it should be emphasized that considerable improvement also was found among smokers.

Postoperative expansion of dural sac cross-sectional area after unilateral laminotomy for bilateral decompression: correlation with clinical symptoms

OBJECTIVE

Dural sac cross-sectional area (DSCSA) is a way to measure the degree of central spinal canal compression. The objective was to investigate the correlation between the expansion ratio of DSCSA after unilateral laminotomy for bilateral decompression (ULBD) and the clinical results for lumbar spinal stenosis.

METHODS

We retrospectively reviewed the clinical data and radiographs of 103 patients who underwent ULBD for symptomatic spinal stenosis in one year. We compared preoperative and postoperative clinical data and DSCSA and evaluated the correlation between clinical and radiographic measurements.

RESULTS

There was a significant increase of DSCSA after ULBD (p=0.000) and mean expansion ratio of DSCSA was 203.7±147.2%(range -32.9-826.1%). Clinical outcomes, measured by VAS and ODI were improved significantly not only in early postoperative period, but also in the last follow-up. However, there were no statistically significant correlations between the preoperative DSCSA and clinical symptoms, Perioperative expansion ratio of DSCSA and clinical parameters were also not correlated to the improvement of clinical symptoms significantly in both early postoperative phase and last follow-up.

CONCLUSION

Our result indicates that the DSCSA itself has a definite limitation to be correlated to the clinical symptoms, and thus meticulous correlation between the clinical presentation and MRI imaging is essential in determination of surgical treatment.

Impact and clinical significance of pedicle length on spinal canal and intervertebral foramen area

The aim of this study was to measure changes in the cross-sectional area of the spinal canal and the area of the intervertebral foramen for each pedicle segment before and after the pedicle extension using computer-simulated transpedicular osteotomy to provide a theoretical basis for clinical decompression in the lumbar spinal canal. Using spiral CT scanning of the original lumbar spine, a finite element model was established. The pedicle was cut and extended by 2 mm, 4 mm, 6 mm, and 8 mm for respective modeling. The changes in the area of each plane of the vertebral canal and the area of the intervertebral foramen were measured. With the gradual extension of the pedicle, the areas of the spinal canal and intervertebral foramen also significantly increased compared with those of the original lumbar spine (P<0.05). The extension of the pedicle using transpedicular osteotomy can significantly increase the cross-sectional area of the lumbar canal and the area of the intervertebral foramen. This finding provides a new theoretically practicable method for the clinical decompression of the lumbar spinal canal.