Risk factor for unsatisfactory outcome after lumbar foraminal and far lateral microdecompression

Percutaneous endoscopic lumbar discectomy for extreme lateral lumbar disc herniation

Background

Far lateral disc herniation (FLDH) constitutes a minor portion of the total discectomy workload for spine surgeons. So far, there is still a debate about the term "extreme lateral," and in general, it describes the intra - and extraforaminal position of the disc herniation. We present a surgical treated case series in which the disc herniation on the lumbar spine was still ventral of the exiting nerve root far outside of the foramen.

Methods

Study Design and Patient Characteristics: retrospective analysis of 14 surgical treated patients. Surgical Technique: In all patients, the so-called foraminal retreat maneuver (percutaneous endoscopic lumbar discectomy) was performed. A foraminoscope with a 15° optic orientation and a nonbeveled working sleeve were used in all cases. The aforementioned technique represents a modification of the "inside-out" endoscopic surgery on the lumbar spine.

Results

We treated 11 male and 3 female patients with an average age of 67 years and 66 years, respectively. Except for one, 13 patients presented with clear monoradicular symptoms accompanied by mild-to-moderate neurological deficits. In 11 cases, the disc herniation exhibited cranial migration; two were at the disc level, and in another case, caudal migration was observed. Immediate pain relief and significant improvement of neurological symptoms occurred in all patients. Two patients developed neuropathic pain, which improved after conservative treatment within 6 weeks following the procedure. No recurrence was observed in this case series.

Conclusion

Patients suffering from extreme lateral lumbar disc herniation were found to be significantly older. Furthermore, there is a higher tendency toward male patients and cranial migration of the herniation. The described and modified inside-out technique, along with a 15° optic, allows for clear identification of the exiting nerve root and safe removal of the displaced disc herniation far outside of the spinal canal and foramen. No complications occurred in this small series, and the development of neuropathic pain appears to be relatively common.

A transfacet approach to the lumbar nerve root canal: technical note

BACKGROUND

Intraforaminal and extraforaminal nerve root compressions caused by disk herniation or stenosis are relatively common causes of lumbar radiculopathy. Currently, the two available surgical treatment methods are decompression from the spinal canal or lateral decompression via the Wiltse approach.

OBJECTIVE

To describe a novel transosseous approach to the lumbar nerve root canal.

METHODS

Transfacet foraminotomy was performed in 11 patients with intraforaminal or extraforaminal disk herniation. The outcome was measured using the Patient Satisfaction Index (PSI), need for reoperation, radiographic criteria, and finite element analysis.

RESULTS

We noted that at the time of dismissal, PSI scores of 1 and 3 were reported by 10 and one patients, respectively. At the last follow-up, 10 patients reported a PSI score of 1 or 2. Two patients required reoperation because of recurrent disk herniation. Two patients underwent computed tomography (CT) postoperatively, which showed the transfacet approach. Intriguingly, a second postoperative CT after one month showed that the hole through the facet joint had shrunk significantly.

CONCLUSION

A posterior-anterior transfacet approach for intraforaminal or extraforaminal disk herniations using an ellipsoid facetectomy is safe and allows for fast and comfortable decompression of the nerve root without compromising the long-term strength of the facet joint.

Magnetic Resonance Imaging Predictors of Surgical Difficulty in Transforaminal Endoscopic Lumbar Discectomy for Far-Lateral Disc Herniation Under Local Anesthesia

Background/Objectives: Transforaminal endoscopic lumbar discectomy (TELD) is a minimally invasive spinal surgery known for its effectiveness, lower complication rates, faster recovery, and ability to be performed under local anesthesia. However, foraminal narrowing or access pain during the transforaminal approach can delay or hinder surgery in patients with far-lateral lumbar disc herniation (LDH). The objectives of this study were to identify predictive factors from preoperative magnetic resonance imaging (MRI) findings and demographics and discuss the optimization of surgical strategies. Methods: This retrospective study included 75 patients with far-lateral LDH who underwent TELD. Preoperative demographics and MRI findings were analyzed. Surgical data, including operative time, length of hospital stay, and intraoperative pain, were recorded. Postoperative outcomes, including complications, revision surgeries, and global outcomes based on the modified Macnab criteria, were evaluated. Preoperative clinical and radiological factors affecting the operative data and results were analyzed. Results: A higher foraminal stenosis grade was significantly correlated with prolonged operative time (p < 0.01) and extended hospital stay (p < 0.01). Extraforaminal LDH was associated with more severe access pain (p < 0.01) owing to increased nerve root irritation. Access pain was significantly correlated with operative time (p < 0.01) and hospital stay (p < 0.01). Appropriate surgical techniques and intraoperative pain management can mitigate these challenges. Conclusions: Preoperative MRI findings, particularly the grade of foraminal narrowing and herniation zone, can predict surgical difficulty and outcomes in TELD for far-lateral LDH. These insights can guide tailored strategies to reduce access pain and improve procedural success under local anesthesia.

Lumbar Decompression Using the Far-Lateral Approach: Patient-Reported Outcome is Associated With the Involved Vertebral Level and Coronal Segmental Angle

STUDY DESIGN

A single-centre retrospective study of prospectively collected data.

OBJECTIVE

Analyse factors associated with the patient-reported outcome after far lateral decompression surgery (FLDS) for lumbar nerve root compression using the far-lateral approach.

SUMMARY OF BACKGROUND DATA

To date, no studies have investigated the influence of vertebral level, coronal segmental Cobb angle, and the nature of the compressive tissue (hard or soft) on the patient-reported outcome following FLDS.

PATIENTS AND METHODS

Patients who had undergone FLDS between 2005 and 2020 were included. Coronal segmental angle (CSCA) was measured on preoperative, posteroanterior radiographs. The primary outcome measure was the core outcome measures index (COMI) score at two years' follow-up (2Y-FU). Patients who had undergone microsurgical decompression using a midline approach served as a comparator group.

RESULTS

There were 148 FLDS and 463 midline approach patients. In both groups, there was a significant improvement in the COMI score from preoperative to 2Y-FU ( P <0.0001), with greater improvement in patients treated at higher vertebral levels than in those treated at L5/S1 ( P =0.014). Baseline COMI, American Society of Anesthesiologists grade, body mass index, and low back pain as the "chief complaint" all had a significant association with the two-year COMI score. The nature of compressive tissue showed no association with the COMI score at 2Y-FU. In the FLDS group, there was a statistically significant correlation between the preoperative CSCA and the change in COMI score preoperatively to 2Y-FU ( P <0.001). The association was retained in the multiple regression analysis, controlling for confounders. A one-degree increase in CSCA was associated with a 0.35-point worse COMI score at 2Y-FU ( P =0.003).

CONCLUSION

Treatment of far lateral nerve root compression showed an overall good patient-reported outcome, but with less improvement with advanced CSCA. Modified approaches and techniques might be preferable for levels L5/S1.

Outcomes of FETD versus UBE in the treatment of L5S1 foraminal stenosis: A comparative study

Background

The L5S1 level exhibits unique anatomical features compared with other levels. This makes minimally invasive surgery for L5S1 foraminal stenosis (FS) challenging. This study compared the surgical outcomes of full endoscopic transforaminal decompression (FETD) and unilateral biportal endoscopy with the far-lateral approach (UBEFLA) in patients with L5S1FS.

Methods

In this retrospective study, 49 patients with L5S1FS were divided into two groups. Of these, 24 patients underwent FETD, 25 patients underwent UBEFLA. The study assessed demographic data, leg pain visual analog scale (VAS) score, back pain VAS score, Oswestry Disability Index (ODI), modified MacNab outcome scale, and radiographic parameters including postoperative lateral facet preservation (POLFP).

Results

The Mann-Whitney U test revealed that the UBEFLA group exhibited a higher VAS score for back pain at one week after the operation, whereas the FETD group exhibited a higher leg pain VAS score 6 weeks after the operation. All four undesired MacNab outcomes in the FETD group were attributed to residual leg pain, whereas all five undesired MacNab outcomes in the UBEFLA group were due to recurrent symptoms. Radiographically, the FETD group exhibited greater POLFP.

Conclusions

When L5S1FS is performed, there may be challenges in adequately clearing the foraminal space in FETD. On the other hand, UBEFLA allowed for a more comprehensive clearance. However, this advantage of UBEFLA was associated with spinal instability as a future outcome.

Transforaminal Unilateral Biportal Endoscopic Spinal Surgery for Extraforaminal Lumbar Disc Herniation: A Retrospective Observational Study

OBJECTIVE

Biportal endoscopic spinal surgery (BESS) is recommended as a safer and less destructive option for lumbar disc herniations. However, limited data exist on clinical outcomes for extraforaminal lumbar disc herniation (ELDH) surgery. This retrospective study presents our preliminary experience with transforaminal unilateral BESS for ELDH.

METHODS

Patients with lumbar radiculopathy refractory to conservative treatment, diagnosed with ELDH by magnetic resonance imaging, and treated with transforaminal unilateral BESS in 2021-2023 in 2 institutions in Taiwan were eligible for inclusion. Those with lumbar spondylolisthesis grade 2 or more with segmental instability, history of drug abuse or psychiatric diseases, or with a follow-up duration <1 year were excluded. Primary outcomes included visual analog scale for pain, assessed at 1 week, 1 month, 6 months, and 1 year using generalized estimating equations analysis; success and satisfaction of BESS graded by the Macnab criteria; and perioperative complications. Secondary outcomes were operative time and hospital length of stay.

RESULTS

Seventeen patients were included in the analysis, with a mean age of 65.8 years; 11 (64.7%) were males and 15 (88.2%) had no prior lumbar spine surgery. mean operative time was 107.9 minutes, and length of stay was 3.5 days. Graded by Macnab criteria, 16 (94.1%) of patients had good to excellent outcomes. Only 1 patient experienced complications. No recurrence/reoperation was observed. Generalized estimating equations analysis showed that postoperative visual analog scale scores decreased significantly at 1 week (adjusted Beta [aBeta] = -5.47, standard error: 0.29, P < 0.001), 1 month (aBeta = -5.82), 6 months (aBeta = -5.88), and 1 year (aBeta = -6.29).

CONCLUSIONS

Transforaminal unilateral BESS is an alternative and feasible method for treating ELDH, producing good surgical outcomes with few complications and sustaining pain improvement. Future studies with larger patient numbers and comparisons between BESS and other minimally invasive techniques for ELDH are warranted.

Factors affecting return to work following endoscopic lumbar foraminal stenosis surgery: A single-center series

Background

This study evaluates the factors affecting the return to work of endoscopic surgery for lumbar foraminal stenosis (LFS), including symptoms, functional status, complications, and reoperation rates.

Methods

The authors' retrospective cohort study included 100 consecutive patients (50 males and 50 females) diagnosed with LFS who underwent endoscopic surgery at Trotsky National Research Center of Surgery between January 2018 and December 2021.

Results

There were no significant differences in age and preoperative visual analog scale and Oswestry disability index scores between the male and female groups, time to return to work for different patient groups after undergoing endoscopic lumbar foraminotomy (ELF). However, patients with more severe stenosis and comorbidities may take longer to recover. Confounding factors were patient age, preoperative physical function, and job requirements.

Conclusion

This study confirms that study ELF can effectively improve symptoms associated with lumbar radiculopathy, as well as back pain, and improve patients' quality of life. Comorbidity, smoking status, and complications prolong the time to return to work following ELF surgery compared to healthy subjects.

Transforaminal Endoscopic Lumbar Foraminotomy for Juxta-Fusional Foraminal Stenosis

Adjacent segment foraminal stenosis is a significant adverse event of lumbar fusion. Conventional revision surgery with an extended fusion segment may result in considerable surgical morbidity owing to extensive tissue injury. Transforaminal endoscopic lumbar foraminotomy (TELF) is a minimally invasive surgical approach for symptomatic foraminal stenosis. This study aimed to demonstrate the surgical technique and clinical outcomes of TELF for the treatment of juxta-fusional foraminal stenosis. Full-scale foraminal decompression was performed via a transforaminal endoscopic approach under local anesthesia. A total of 22 consecutive patients who had undergone TELF were evaluated. The included patients had unilateral foraminal stenosis at the juxta-fusional level of the previous fusion surgery, intractable lumbar radicular pain despite at least six months of non-operative treatment, and verified pain focus by imaging and selective nerve root block. The visual analog scale and Oswestry Disability Index scores significantly improved after the two-year follow-up period. The modified MacNab criteria were excellent in six patients (27.27%), good in 12 (55.55%), fair in two (9.09%), and poor in two (9.09%), with a 90.91% symptomatic improvement rate. No significant surgical complications were observed. The minimally invasive TELF is effective for juxta-fusional foraminal stenosis.

Biportal endoscopic paraspinal decompressive foraminotomy for lumbar foraminal stenosis: clinical outcomes and factors influencing unsatisfactory outcomes

BACKGROUND

Lumbar foraminal stenosis (LFS) is an important pathologic entity that causes lumbar radiculopathies. Unrecognized LFS may be associated with surgical failure, and LFS remains challenging to treat surgically. This retrospective cohort study aimed to evaluate the clinical outcomes and prognostic factors of decompressive foraminotomy performed using the biportal endoscopic paraspinal approach for LFS.

METHODS

A total of 102 consecutive patients with single-level unilateral LFS who underwent biportal endoscopic paraspinal decompressive foraminotomy were included. We evaluated the Visual Analogue Scale (VAS) score and the Oswestry Disability Index (ODI) before and after surgery. Demographic, preoperative data, and radiologic parameters, including the coronal root angle (CRA), were investigated. The patients were divided into Group A (satisfaction group) and Group B (unsatisfaction group). Parameters were compared between these two groups to identify the factors influencing unsatisfactory outcomes.

RESULTS

In Group A (78.8% of patients), VAS and ODI scores significantly improved after biportal endoscopic paraspinal decompressive foraminotomy (p < 0.001). However, Group B (21.2% of patients) showed higher incidences of stenosis at the lower lumbar level (p = 0.009), wide segmental lordosis (p = 0.021), and narrow ipsilateral CRA (p = 0.009). In the logistic regression analysis, lower lumbar level (OR = 13.82, 95% CI: 1.33-143.48, p = 0.028) and narrow ipsilateral CRA (OR = 0.92, 95% CI: 0.86-1.00, p = 0.047) were associated with unsatisfactory outcomes.

CONCLUSIONS

Significant improvement in clinical outcomes was observed for a year after biportal endoscopic paraspinal decompressive foraminotomy. However, clinical outcomes were unsatisfactory in 21.2% of patients, and lower lumbar level and narrow ipsilateral CRA were independent risk factors for unsatisfactory outcomes.

Morphometric change in intervertebral foramen after percutaneous endoscopic lumbar foraminotomy: an in vivo radiographic study based on three-dimensional foramen reconstruction

PURPOSE

This study aimed to perform in vivo three-dimensional (3D) quantitative measurements of morphometric changes in the foramen in patients with lumbar foraminal stenosis (LFS) undergoing percutaneous endoscopic lumbar foraminotomy (PELF) and investigate the relationship between anatomical changes in the foramen and clinical outcomes.

METHODS

We retrospectively reviewed consecutive patients with LFS treated with PELF between January 2016 and September 2020 at our centre. Clinical outcomes were evaluated. Foraminal volume (FV) and foraminal minimal area (FMA) were calculated using a novel vertebral and foramen segmentation method. A comparison of the anatomical parameters of the foramen were conducted between the satisfied and unsatisfied groups divided based on the modified MacNab criteria.

RESULTS

A total of 26 eligible patients with a mean follow-up of 3.6 years were enrolled. A significant increase was found in overall FV (71.5%) from 1.436 ± 0.396 to 2.464 ± 0.719 cm3 (P < 0.001) and FMA (109.5%) from 0.849 ± 0.207 to 1.780 ± 0.524 cm2. All clinical outcomes were significantly improved (P < 0.001) after PELF. No significant difference was found in changes in neither FV nor FMA between the two groups.

CONCLUSION

Clinical results and foraminal dimensions improved significantly after PELF, indicating that PELF was a prominent technique suitable for LFS because of the direct decompression at impingement structures. No relationship was found between morphometric changes and clinical outcomes, revealing that full-scale endoscopic decompression is necessary and adequate for LFS, and unsatisfactory outcomes are less likely to result from decompression procedure.

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.

Efficacy of Repeat Percutaneous Endoscopic Lumbar Decompression for Reoperation of Lumbar Spinal Stenosis: A Retrospective Study

Purpose

To evaluate the efficacy of repeat percutaneous endoscopic lumbar decompression (PELD) in lumbar spinal stenosis (LSS) reoperation.

Patients and Methods

This study included patients with LSS who relapsed following treatment with PELD therapy between March 2017 and March 2020. Visual analog scale (VAS) scores and Oswestry Disability Index (ODI) were analyzed preoperatively, postoperatively at 3, 6, 12, and 24 months, and at final follow-up. The modified MacNab criteria were used to assess clinical effects. All complications were recorded.

Results

At a mean follow-up of 3 years, 24 patients with LSS who underwent repeat PELD were identified. The patients' mean operative time was 122.3±29.2 min, blood loss was 12.5±5.3 mL, and mean hospital stay was 7.0±1.9 days. VAS leg-pain score improved from 6.1±1.0 to 2.0±1.2 (P<0.001), VAS back-pain score improved from 6.2±0.8 to 2.1±1.1 (P<0.001), and ODI improved from 68.9±6.0 to 20.9±5.6 (P <0.001). According to the modified MacNab criteria, the good-to-excellent rate was 83.3%. Postoperative complications, including hematoma, nerve root injury, and dural injury, developed in four patients.

Conclusion

Repeat PELD for reoperation in patients with LSS has a good clinical effect, and is recommended in routine clinical practice. Careful intraoperative manipulation is recommended to prevent complications.

Correlation of Foraminal Parameters with Patient-Reported Outcomes in Patient with Degenerative Lumbar Foraminal Stenosis

The relationship between quantitative anatomic parameters in MRI and patient-reported outcomes (PROs) before and after surgery in degenerative lumbar foraminal stenosis remains unknown. We included 58 patients who underwent transforaminal lumbar interbody fusion (TLIF) for single-level degenerative disc disease with foraminal stenosis between February 2013 and June 2020. PROs were evaluated using the visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and EuroQol-5D (EQ-5D). The foraminal parameters assessed using preoperative MRI included foraminal height, posterior intervertebral disc height, superior and inferior foraminal width, and foraminal area. The correlation between foraminal parameters and PROs before operation, at 1 year follow-up, and change from baseline were assessed. The associations between the aforementioned parameters were examined using linear regression analysis. The analysis revealed that among these parameters, superior foraminal width was found to be significantly correlated with ODI and EQ-5D at the 1 year follow-up and with change in ODI and EQ-5D from baseline. The associations remained significant after adjustment for confounding factors including age, sex, body mass index, and duration of hospital stay. The results indicated that in degenerative lumbar foraminal stenosis, decreased superior foraminal width was associated with better improvement in disability and quality of life after TLIF.

Percutaneous Intervertebral-Vacuum Polymethylmethacrylate Injection for Foraminal Stenosis with Degenerative Lumbar Scoliosis

BACKGROUND

Percutaneous intervertebral-vacuum polymethylmethacrylate injection (PIPI) is a minimally invasive procedure for low back pain in elderly patients with degenerative lumbar scoliosis (DLS). Patients with DLS often have radiculopathy as a result of foraminal stenosis in addition to low back pain. The purpose of this study was to evaluate the clinical and radiologic results of PIPI for foraminal stenosis with radiculopathy in elderly patients with DLS.

METHODS

We included patients with de novo DLS aged 65 years or older who underwent PIPI. The presence of an intervertebral vacuum on computed tomography and bone marrow edema on magnetic resonance imaging was required for inclusion. The intersegmental radiologic parameters on plain radiographs and computed tomography and the extent of bone marrow edema on magnetic resonance imaging were measured. The clinical outcomes were evaluated using the visual analog scale (VAS) and Oswestry Disability Index (ODI).

RESULTS

We enrolled 40 patients with DLS who underwent PIPI. There were 16 men and 24 women, and the mean age was 79.0 ± 6.3 years. The mean foraminal height and extent of bone marrow edema showed a significant increase and reduction, respectively, after PIPI (P < 0.05). VAS score for radiculopathy and ODI significantly improved after PIPI (P < 0.01). The minimum clinically important differences in VAS score for radiculopathy and ODI at the final follow-up were 73.9% and 63.6%, respectively.

CONCLUSIONS

PIPI is a minimally invasive procedure not only for low back pain but also for radiculopathy in elderly patients with DLS. It leads to intervertebral stabilization and indirect decompression of the foramen.

Comparison of Microscopic Decompression and Biportal Endoscopic Spinal Surgery in the Treatment of Lumbar Canal Stenosis and Herniated Disc: A One-year Follow-up

Backgrounds. Microscopic decompression (MD) has been widely used as an alternative to open decompression. Lately, biportal endoscopic spinal surgery (BESS) - a new approach in minimal-invasive spinal surgery – has also been used with good results.  Although both groups can achieve adequate lumbar decompression, there is still a lack of evidence regarding their comparison. We aim to compare the outcomes of both techniques in a one-year follow-up. Methods. This is a retrospective study in 100 consecutive patients with symptomatic lumbar spine compression due to herniated nucleus pulposus (HNP) and lumbar canal stenosis (LCS) that was treated by either BESS or MD. Clinical evaluations using Visual Analog Score (VAS), Oswestry Disability Index (ODI), and SF-36 questionnaire were obtained. Objective data such as surgery duration, amount of postoperative drain production, and hospital length of stay were collected. Complications were noted throughout the follow-up time. Results. The BESS group had a significantly lesser surgical duration, drain production, and length of stay. At one year follow-up, both groups achieved significant improvement in VAS, ODI, and SF-36 compared to the preoperative condition. Complications were not observed in the BESS group. Conclusions. Both procedures were comparably effective to treat lumbar stenosis. Although this study shows superiority with BESS technique in immediate and long-term follow-up, the final choice may depend on the surgeon's preference

Unilateral Biportal Endoscopy for Decompression of Extraforaminal Stenosis at the Lumbosacral Junction: Surgical Techniques and Clinical Outcomes

Objective

The aims of this study were to describe the unilateral biportal endoscopic (UBE) technique for decompression of extraforaminal stenosis at L5–S1 and evaluate 1-year clinical outcomes. Especially, we evaluated compression factors of extraforaminal stenosis at L5–S1 and described the surgical technique for decompression in detail.

Methods

Thirty-five patients who underwent UBE decompression for extraforaminal stenosis at L5–S1 between March 2018 and February 2019 were enrolled. Clinical results were analyzed using the MacNab criteria, the visual analogue scale (VAS) for back and leg pain, and the Oswestry Disability Index (ODI). Compression factors evaluated pseudoarthrosis within the transverse process of L5 and ala of sacrum, disc bulging with or without osteophytes, and the thickened lumbosacral and extraforaminal ligament.

Results

The mean back VAS was 3.7±1.8 before surgery, which dropped to 2.3±0.8 at 1-year postoperative follow-up (p<0.001). There was a significant drop in postoperative mean VAS for leg pain from 7.2±1.1 to 2.3±1.2 at 1 year (p<0.001). The ODI was 61.5 before surgery and 28.6 (p<0.001). Pseudoarthrosis between the transverse process and the ala was noted in all cases (35 of 35, 100%). Pure disc bulging was seen in 12 patients (34.3%), and disc bulging with osteophytes was demonstrated in 23 patients. The thickened lumbosacral and extraforaminal ligament were identified in 19 cases (51.4%). No complications occurred in any of the patients.

Conclusion

In the current study, good surgical outcomes without complications were achieved after UBE decompression for extraforaminal stenosis at L5–S1.

Long-term Outcomes after Microsurgical Decompression of Lumbar Foraminal Stenosis and Adverse Effects of Preoperative Scoliosis: A Prospective Cohort Study

Lumbar foraminal stenosis is a common disorder, with surgical treatment varying from simple decompression to interbody fusion. It is often associated with degenerative lumbar scoliosis, but the effects of scoliosis on outcomes are unclear. The objectives of this study were to clarify long-term outcomes after microsurgical decompression of lumbar foraminal stenosis through Wiltse’s approach and to determine the effects of scoliosis on these outcomes. A total of 86 consecutive patients with lumbar foraminal stenosis were prospectively followed after microsurgical decompression. They were categorized in multiple subcohorts with follow-up durations ranging from 6 months to 5 years. Outcomes were assessed using the Short Form 36 questionnaire (average physical scores and bodily pain scores). Local Cobb angle of the operative segment was measured preoperatively, and its effects on outcomes were analyzed. Average physical scores improved significantly from 33.8 (95% confidence interval [CI]: 29.1–38.5) preoperatively to 59.5 (95% CI: 54.6–64.3) at 6 months postoperatively and remained improved for 5 years. Bodily pain scores improved significantly from 23.7 (95% CI: 18.7–28.6) preoperatively to 56.3 (95% CI: 51.2–61.6) at 6 months postoperatively and remained improved for 5 years. Patients with preoperative scoliosis (local Cobb angle >10 degrees) had poorer outcomes: average physical scores were worse by 9.6 points (p = 0.07) and bodily pain scores were worse by 12.1 points (p = 0.02), compared with patients without scoliosis (local Cobb angle ≤10 degrees). Microsurgical foraminal decompression produced overall excellent outcomes in patients with lumbar foraminal stenosis. Preoperative scoliosis attenuated these beneficial effects.

The irony of the transforaminal approach: A comparative cohort study of transforaminal endoscopic lumbar discectomy for foraminal versus paramedian lumbar disc herniation

Transforaminal endoscopic lumbar discectomy (TELD) is useful for soft lumbar disc herniation (LDH). Although the transforaminal approach can reach the foraminal disc zone, the risk of exiting nerve root irritation along the path is considerable. Few studies have assessed the difficulties of TELD for foraminal LDH. The objective of this study is to compare the clinical results of TELD between foraminal or far-lateral LDH and paramedian LDH.Between June 2016 and July 2017, 135 consecutive patients with single-level LDH were treated with TELD for 2 years. Among them, 25 patients had foraminal or far-lateral LDH (foraminal group), and the remaining 110 patients had central or subarticular LDH (paramedian group). Perioperative data and clinical outcomes were evaluated using the visual analog pain scale, Oswestry Disability Index, and modified Macnab criteria.The foraminal group showed a higher rate of significant access pain (24.00% vs 8.19%, P < .05). The foraminal group also had a longer duration of surgery, length of hospital stay, and return to work (all P < .05). Pain scores and functional status were significantly improved in both groups. Although there were no differences in the outcomes at 2 years postoperatively, early pain and disability at 6 weeks were higher in the foraminal group.Ironically, the early clinical results of TELD for foraminal LDH may be less favorable than those for paramedian LDH. Therefore, great care should be taken during TELD for foraminal or far-lateral LDH.

Clinical outcomes for patients with lateral lumbar radiculopathy treated by percutaneous endoscopic transforaminal discectomy versus tubular microdiscectomy: A retrospective review

BACKGROUND

Surgical management of lateral lumbar radiculopathy is evolving. TMD (Tubular microdiscectomy) and TELD (Transforaminal endoscopic lumbar discectomy) have emerged as viable MIS treatments. We aim to compare clinical outcomes of both techniques for the treatment of lateral lumbar radiculopathy in relation to pre-operative lumbar foraminal stenosis grade (LFS).

METHODS

Retrospective observational cohort study of patients with back and leg pain from single level foraminal nerve root compression that underwent TMD or TELD. Data analyzed included pre- and post-operative VAS leg and back pain, MacNab clinical outcome scores, hospital length of stay, complication rates, and operative time. Outcomes were correlated with a pre-operative MRI grading system for LFS.

RESULTS

109 patients were enrolled (71 TELD and 38 TMD). Back and leg VAS pain scores improved in TELD and TMD (p < 0.0001). Patients with grade III stenosis showed significantly higher VAS scores (p < 0.01), and worse functional outcomes at latest follow-up compared with grade I/II LFS. Overall, there was no difference in outcome between procedure groups except that TMD VAS back pain scores were lower than TELD at last follow up (p < 0.05). Clinical outcome comparisons between procedures relating to LFS grade showed higher correlation of LFS to TELD (Spearman's rho (ρ)= 0.342 for TMD and 0.606 TELD). Regression analyses demonstrated correlation between higher-grade foraminal stenosis and poorer outcomes in TELD and TMD.

CONCLUSIONS

Both TELD and TMD are viable for treating lateral lumbar radiculopathy. Higher-grade foraminal stenosis can be indicative of poorer outcomes regardless of procedure type, however, the severity of pre-operative LFS correlates with clinical outcomes in TELD more significantly than TMD.

Quantitative correlation of lumbar foraminal stenosis with local morphological metrics

PURPOSE

Clinical evaluation of lumbar foraminal stenosis typically includes qualitative assessments of perineural epidural fat content around the spinal nerve root and evaluation of nerve root impingement. The present study investigates the use of several morphological MRI-derived metrics as quantitative predictors of foraminal stenosis grade.

METHODS

62 adult patients that underwent lumbar spine MRI evaluation over a 1-month duration in 2018 were included in the analysis. Radiological gradings of stenosis were captured from the existing clinical electronic medical record. Clinical gradings were recorded using a 0-5 scale: 0 = no stenosis, 1 = mild stenosis, 2 = mild-moderate stenosis, 3 = moderate stenosis, 4 = moderate-severe stenosis, 5 = severe stenosis. Quantitative measures of perineural epidural fat volume, nerve root cross-sectional area, and lumbar pedicle length were derived from T1 weighted sagittal spine MRI on each side of all lumbar levels. Spearman correlations of each measured metric at each level were then computed against the stenosis gradings.

RESULTS

A total of 347 volumetric segmentation and radiological foraminal stenosis grade sets were derived from the 62-subject study cohort. Statistical analysis revealed significant correlations (p < 0.001) between the volume of perineural fat and stenosis grades for all lumbar vertebral levels.

CONCLUSION

The results of the study have demonstrated that segmented volumes of perineural fat predict the severity of clinically scored foraminal stenosis. This finding motivates further development of automated perineural fat segmentation methods, which could offer a quantitative imaging biometric that yields more reproducible diagnosis, assessment, and tracking of foraminal stenosis.

Ameliorated Full-Endoscopic Transforaminal Decompression for L5-S1 Foraminal and Extraforaminal Stenosis

STUDY DESIGN

This is a retrospective review.

OBJECTIVE

To describe a modified surgical technique, full-endoscopic transforaminal decompression (FETD) in patients with L5-S1 foraminal stenosis or extraforaminal stenosis (EFS) and to detail the short-term results.

SUMMARY OF BACKGROUND DATA

Performing FETD surgery for L5-S1 FS and EFS is challenging because of high iliac crests in most cases and the difficulty in accurately differentiating between FS and EFS by images preoperatively.

MATERIAL AND METHODS

Patients who had solitary unilateral L5-S1 FS or EFS and had undergone FETD between October 2014 and December 2017 were included. In total, 22 patients underwent FETD for L5 root compressions at the L5-S1 levels. All patients were followed up for more than 1 year.

RESULTS

The mean visual analog scale score for back and leg pain, assessed preoperatively and at 12 months postoperatively, improved from 6.3±1.7 to 1.59±1.30 and from 7.29±0.78 to 1.41±1.20, respectively. The mean Oswestry Disability Index improved from 61.53% preoperatively to 15.8% at 12 months postoperatively. Neurovascular injury-related complications were absent in all these cases.

CONCLUSION

Successful short-term clinical outcome is achievable using the ameliorated FETD technique for treating L5-S1 FS and EFS.

Does "Coronal Root Angle" Serve as a Parameter in the Removal of Ventral Factors for Foraminal Stenosis at L5-S1 In Stand-alone Microendoscopic Decompression?

STUDY DESIGN

Prospective single-center cohort study.

OBJECTIVE

The present study aims to investigate the causes of failure of L5/S1 foraminal stenosis, and it is hypothesized that the newly defined "L5 coronal root angle (CRA)" may be a parameter in the removal of ventral pathologies.

SUMMARY OF BACKGROUND DATA

Lumbar foraminal stenosis is an important cause of recurrent leg pain after central spinal stenosis surgery. Although it can be seen at all levels, L5/S1 is the level at which it is most frequently seen due to its specific characteristics, with success rate is lower than other levels after foraminal decompression.

METHODS

L5/S1 microendoscopic foraminal decompression was performed to 51 patients. According to Japanese Orthopedic Association (JOA) improvement at 12-month follow-up, those with improvement >20% were classified as Group 1 and <20% were classified as Group 2. The patients who underwent discectomy in addition to foraminotomy formed Group 3. Lumbar lordosis angle, segmental lordosis angle, anterior disc height, pelvic tilt, pelvic incidence, sacral slope, relative disc height ratio, pedicle height/vertebral body height ratio, L5 depth, L5 CRA, and anterior disc height/ posterior disc height ratio parameters were measured with lumbar radiographic views, computed tomography (CT), and magnetic resonance imaging (MRI).

RESULTS

Among the parameters compared between groups, L5 CRA, posterior disc height, anterior disc height/posterior disc height, relative disc height ratio, and lumbar lordosis angle during extension were seen to be statistically significantly related with low success rate.

CONCLUSION

Failure to remove the ventral pathologies when the L5 CRA is <112. 1º may lead to failed results. Besides, in cases wherein the posterior disc height is <2.85 mm or the anterior/posterior disc height ratio is >3.98, approaches to restoring disc height rather than stand-alone posterior decompression may reduce the possibility of failure.

LEVEL OF EVIDENCE

2.

Combined Effects of Graded Foraminotomy and Annular Defect on Biomechanics after Percutaneous Endoscopic Lumbar Decompression: A Finite Element Study

Percutaneous endoscopic technology has been widely used in the treatment of lumbar disc stenosis and herniation. However, the quantitative influence of percutaneous endoscopic lumbar decompression on spinal biomechanics of the L5–S1 lumbosacral segment remains poorly understood. Hence, the objective of this study is to investigate the combined effects on the biomechanics of different grades of foraminotomy and annular defect for the L5–S1 segment. A 3D, nonlinear, detailed finite element model of L4–S1 was established and validated. Changes in biomechanical responses upon stimulation to the intact spine during different degrees of resection were analyzed. Measurements included intervertebral rotation, intradiscal pressure, and the strain of disc structure under flexion, extension, left/right lateral bending, and left/right axial rotation under pure bending moments and physiological loads. Compared with the intact model, under prefollower load, annular defect slightly decreased intervertebral rotation by −5.0% in extension and 2.2% in right axial rotation and significantly increased the mean strain of the exposed disc by 237.7% in all loading cases. For right axial rotation, unilateral total foraminotomy with an annular detect increased intervertebral rotation by 29.5% and intradiscal pressure by 57.6% under pure bending moment while the maximum corresponding values were 9.8% and 6.6% when the degree of foraminotomy was below 75%, respectively. These results indicate that percutaneous endoscopic lumbar foraminotomy highly maintains spinal stability, even if the effect of annular detect is taken into account, when the unilateral facet is not totally removed. Patients should avoid excessive extension and axial rotation after surgery on L5–S1. The postoperative open annular defect may substantially increase the risk of recurrent disc herniation.

Anterior Lumbar Interbody Fusion May Provide Superior Decompression of the Foraminal Space Compared with Direct Foraminotomy: Biomechanical Cadaveric Study

OBJECTIVE

The objective of this cadaveric biomechanical study was to compare the area of the foraminal space during motion in the intact condition, after direct decompression via foraminotomy, and after indirect decompression via anterior lumbar interbody spacer insertion.

METHODS

Eight (8) L5-S1 cadaver specimens were used for testing. Each specimen was tested in the intact state, after posterior foraminotomy, and after standalone anterior lumbar interbody fusion (ALIF). Each specimen was 3-dimensional imaged under neutral loading, flexion, and extension. The 3-dimensional images were analyzed for changes in the foraminal area under each loading scenario. A repeat-measures design was used. Outcome measures from testing included the frequency in which an increase in cross-sectional area was observed, as well as the percent increase of the foraminal area for each surgical group and loading direction.

RESULTS

Direct foraminotomy and ALIF maintained the foraminal space during initial distraction under no loading with areas 99.7% and 96.5% of the native foraminal area, respectively (P = 0.955 and P = 0.455). Direct foraminotomy increased the foraminal area significantly during flexion to 112.2% of the area before motion (P = 0.008) while ALIF did not. Direct foraminotomy significantly decreased the foraminal area during extension to 89.2% of the area before motion (P = 0.006). ALIF, however, maintained its initial distraction during extension with 98.2% of the area before motion (P = 0.808).

CONCLUSIONS

ALIF maintains the foraminal area in extension while direct posterior foraminotomy does not.

Clinical outcome of percutaneous lumbar foraminoplasty using a safety-improved device in patients with lumbar foraminal spinal stenosis

Lumbar foraminal spinal stenosis (LFSS) is defined as the narrowing of the nerve root exit associated with a herniated intervertebral disc, osteoarthritic changes in the facet joints, or a hypertrophied ligamentum flavum, which can provoke neurogenic claudication. To achieve effective and safe decompression of the lumbar spinal foramen, a specially designed instrument (Claudicare, SEAWON Meditech, Bucheon-si, Gyeonggi-do, Republic of Korea) for percutaneous lumbar foraminoplasty (PLF) was invented. The purpose of this study was to evaluate the clinical efficacy and safety of the newly devised instrument in patients with LFSS.PLF was performed for LFSS by a single pain physician. For each patient, an 11-point numerical rating scale (NRS) pain score-the Oswestry Disability Index (ODI)-and the duration of walking without radicular pain were evaluated at the 3-month follow-up. The successful responder percentage was defined as ≥50% reduction from the baseline NRS score with improvement in ODI and duration of walking.Among 24 patients who underwent PLF, 15 patients showed successful responses. The NRS pain score and duration of walking without radicular pain were improved significantly from baseline at the 3-month follow-up (P < .01). The ODI was also decreased, but the difference was not statistically significant (P = .09). The NRS pain score and walking duration without pain at 3 months were statistically significantly different between the groups (P < .001 and P = .01, respectively), whereas there was no statistically significant difference in improvement in ODI between the groups (P = .23). No serious adverse events occurred in the study.In conclusion, PLF using the Claudicare device may be an optimal and safe option for managing intractable LFSS on an outpatient basis.

Percutaneous Stenoscopic Lumbar Decompression with Paramedian Approach for Foraminal/Extraforaminal Lesions

The lumbar foramen is affected by different degenerative diseases, including extraforaminal disc herniation, foraminal stenosis (FS), and degenerative or spondylolytic spondylolisthesis. The purpose of this study was to describe percutaneous stenoscopic lumbar decompression with a paramedian approach (para-PSLD) for foraminal/extraforaminal lesions. All operative procedures were performed using a complete uniportal endoscopic instrument system. The para-PSLD can be easily applied to patients with FS and narrow disc space or facet joint hypertrophy. The anatomical view of a para-PSLD is similar to that of a conventional open surgery and allows for good visualization of the foraminal/extraforaminal areas. We suggest that para-PSLD is an alternative and minimally invasive procedure to treat degenerative lumbar foraminal/extraforaminal stenoses.

Predictors of Clinical Outcome After Endoscopic Partial Facetectomy for Degenerative Lumbar Foraminal Stenosis

OBJECTIVE

Endoscopic partial facetectomy (EPF) is an effective option for decompressing the lumbar exiting root without causing spinal instabilities in the treatment of patients with degenerative lumbar foraminal stenosis. The aim of the present study was to identify the preoperative risk factors of poor clinical outcomes after EPF in patients with degenerative lumbar foraminal stenosis.

METHODS

A total of 51 consecutive patients who had undergone EPF from 2012 to 2015 were included in the present study. The clinical outcomes were evaluated using the visual analog scale (VAS), Oswestry disability index (ODI), and Short-Form 36-item (SF-36) outcome questionnaires. The preoperative radiological risk factors were measured using the lumbar Cobb's angle, disc wedging angle, lumbar lordosis (LL), segmental lordosis, disc height index, presence of spondylolisthesis, and morphological changes (no change, horizontal collapse, vertical collapse) of the exiting root within the most stenotic level on preoperative magnetic resonance imaging.

RESULTS

The VAS, ODI, and SF-36 scores had significantly improved at the 1-month follow-up visit compared with the baseline mean values and were maintained within the 2-year follow-up period. A correlation analysis revealed significant relationships between various preoperative factors and clinical outcomes. On multiple regression analysis, the morphological change of vertical collapse significantly predicted the VAS, ODI, and SF-36 scores, and LL significantly predicted the ODI and SF-36 scores.

CONCLUSIONS

A morphological change in vertical collapse found on preoperative magnetic resonance imaging and decreased LL were significant predictors of poor clinical outcomes after EPF in the treatment of lumbar foraminal stenosis.

Unilateral Biportal Endoscopic Spinal Surgery Using a 30° Arthroscope for L5-S1 Foraminal Decompression

Foraminal decompression using a minimally invasive technique to preserve facet joint stability and function without fusion reportedly improves the radicular symptoms in approximately 80% of patients and is considered one of the good surgical treatment choices for lumbar foraminal or extraforaminal stenosis. However, proper decompression was not possible because of the inability to access the foramen at the L5–S1 level due to prominence of the iliac crest. To overcome this challenge, endoscopy-based minimally invasive spine surgery has recently gained attention. Here, we report the technical skills required in unilateral extraforaminal biportal endoscopic spinal surgery using a 30° arthroscope to enable foraminal decompression at the L5–S1 level. Two 0.8-cm portals were created 2 cm lateral from the lateral border of the pedicles at the L5–S1 level. After sufficient working space was made, half of the superior articular process (SAP) in the hypertrophied facet joint was removed using a high-speed burr and a 5-mm wide osteotome, whereas the remaining inside part of the SAP was removed using a Kerrison punch and pituitary punch. The foraminal ligamentum flavum should be removed to inspect the conditions of the L5 exiting root and disc. Removing of the extruded disc could decompress the L5 root. The extraforaminal approach using a 30° arthroscope is considered a minimally invasive alternative technique for decompressing foraminal stenosis at the L5–S1 level that preserves facet stability and provides symptomatic relief.

Clinical and Radiological Outcomes of Foraminal Decompression Using Unilateral Biportal Endoscopic Spine Surgery for Lumbar Foraminal Stenosis

Background

Since open Wiltse approach allows limited visualization for foraminal stenosis leading to an incomplete decompression, we report the short-term clinical and radiological results of unilateral biportal endoscopic foraminal decompression using 0° or 30° endoscopy with better visualization.

Methods

We examined 31 patients that underwent surgery for neurological symptoms due to lumbar foraminal stenosis which was refractory to 6 weeks of conservative treatment. All 31 patients underwent unilateral biportal endoscopic far-lateral decompression (UBEFLD). One portal was used for viewing purpose, and the other was for surgical instruments. Unilateral foraminotomy was performed under guidance of 0° or 30° endoscopy. Clinical outcomes were analyzed using the modified Macnab criteria, Oswestry disability index, and visual analogue scale. Plain radiographs obtained preoperatively and 1 year postoperatively were compared to analyze the intervertebral angle (IVA), dynamic IVA, percentage of slip, dynamic percentage of slip (gap between the percentage of slip on flexion and extension views), slip angle, disc height index (DHI), and foraminal height index (FHI).

Results

The IVA significantly increased from 6.24° ± 4.27° to 6.96° ± 3.58° at 1 year postoperatively (p = 0.306). The dynamic IVA slightly decreased from 6.27° ± 3.12° to 6.04° ± 2.41°, but the difference was not statistically significant (p = 0.375). The percentage of slip was 3.41% ± 5.24% preoperatively and 6.01% ± 1.43% at 1-year follow-up (p = 0.227), showing no significant difference. The preoperative dynamic percentage of slip was 2.90% ± 3.37%; at 1 year postoperatively, it was 3.13% ± 4.11% (p = 0.720), showing no significant difference. The DHI changed from 34.78% ± 9.54% preoperatively to 35.05% ± 8.83% postoperatively, which was not statistically significant (p = 0.837). In addition, the FHI slightly decreased from 55.15% ± 9.45% preoperatively to 54.56% ± 9.86% postoperatively, but the results were not statistically significant (p = 0.705).

Conclusions

UBEFLD using endoscopy showed a satisfactory clinical outcome after 1-year follow-up and did not induce postoperative segmental spinal instability. It could be a feasible alternative to conventional open decompression or fusion surgery for lumbar foraminal stenosis.

Extreme lateral and interlaminar approach for intra-canal and foraminal double disc herniation at lumbosacral level

INTRODUCTION AND OBJECTIVES

There are several approaches for double disc herniation consisting of an intracanal and foraminal lesion. Of several approaches, we introduced extreme lateral and interlaminar approach (ELIA). And we aimed to compare the approach with the conventional combined interlaminar and paraisthmic approach (CIPA).

PATIENTS AND METHODS

The authors reviewed the medical charts of patients who underwent a procedure for a double disc herniation at the lumbosacral level between March 2012 and February 2016 and patients who underwent CIPA or ELIA were selected. For preoperative testing, simple X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) scans were performed. For postoperative outcomes, the Korean version of the Oswestry Disability Index (K-ODI) and Numeric Rating Scale (NRS) at one, two, and three months post-operation were checked.

RESULTS

Eleven patients were given ELIA and twenty-four patients were involved in CIPA. The mean pre K-ODI was 34.1 (±13.9) and 32.4 (±4.0) at each group. 1st, 2nd and 3rd month post-operative K-ODI was 8.2 (±4.1), 6.4 (±2.1) and 5.3 (±2.4) in ELIA and 8.1 (±3.2), 7.1 (±3.5) and 8.4 (±6.4) in CIPA. Post-operative 3rd month K-ODI showed significant difference between two groups (p: 0.005). The mean pre NRS was 8 (±0.9) and 8.6 (±1.0). 1st, 2nd and 3rd month post-operative NRS was 2.4 (±1.5), 2.2 (±1.5) and 2.0 (±0.9) in ELIA and 3.3 (±1.4), 3.3 (±1.6) and 3.7 (±1.9). Post-operative 3rd month NRS showed significant difference between two groups as well (p: 0.001). There were four (19.0%) recurrence cases in CIPA patients group, otherwise there was no recurrence case in ELIA group.

CONCLUSIONS

In the treatment of L5-S1 double disc herniation, the ELIA surgical approach showed better outcomes than the CIPA surgical approach did with respect to pain and K-ODI during a mid-term follow-up examination conducted three months post-operation.

Laser-Assisted Microdiscectomy for Far Lateral Lumbar Disc Herniation at the L5-S1 Level

OBJECTIVE

Laser-assisted paraspinal microdiscectomy for far lateral lumbar disc herniation (LDH) enables direct access to the foraminal or far lateral zone with minimal tissue injury and preserves facet joints, thereby preventing postoperative segmental instability. We demonstrated the clinical outcomes of this technique and discussed the pros and cons of laser use in lumbar disc surgery.

BACKGROUND

The microdiscectomy technique for L5-S1 far lateral zone may be difficult due to the limited surgical field with narrowed disc space, hypertrophied facet, and sacral ala. Thus, we used carbon dioxide (CO₂) laser for sophisticated decompression.

METHODS

Eighty-four patients who were treated with microdiscectomy for far lateral LDH at the L5-S1 level were evaluated. Among them, 40 patients were treated using CO₂ laser-assisted microdiscectomy, and the remaining 44 patients using conventional microdiscectomy. Perioperative and postoperative data were compared between the two groups with 2 years of follow-up. Clinical outcomes were assessed using the visual analog scale (VAS), Oswestry disability index (ODI), and modified Macnab criteria.

RESULTS

VAS and ODI significantly improved in both groups. An excellent or good outcome was rated in 80% and 77.3% of the laser and conventional group, respectively. There was no significant difference in global outcomes. However, hospital stay and time to return to work were significantly shorter in the laser group (p < 0.05).

CONCLUSIONS

CO₂ laser-assisted paraspinal microdiscectomy is effective for treating far lateral LDH. The pinpoint laser scalpel enables delicate and complete decompression in a limited surgical field with minimal tissue trauma.

Minimally Invasive Transtubular Endoscopic Decompression for L5 Radiculopathy Induced by Lumbosacral Extraforaminal Lesions

Study Design

Retrospective study.

Purpose

This study aimed to evaluate the efficacy of minimally invasive transtubular endoscopic decompression for the treatment of lumbosacral extraforaminal lesion (LSEFL).

Overview of Literature

Conventional procedures for surgical decompression for the treatment of LSEFL involve certain technical challenges because the lumbosacral extraforaminal region has unique anatomical features. Moreover, the efficacy of minimally invasive procedures performed via the posterolateral approach for LSEFL has been reported.

Methods

Twenty-five patients who had undergone minimally invasive transtubular endoscopic decompression for the treatment of LSEFL and could be followed up for at least 1 year postoperatively were enrolled. Five of these patients had a history of lumbar surgery, and seven had concomitant adjacent-level spinal stenosis. The clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) lumbar score, numeric rating scale (NRS), and the JOA Back Pain Evaluation Questionnaire (JOABPEQ). The mean postoperative follow-up (FU) duration was 3.8 years.

Results

All procedures could be completed without any severe surgical complications, and all patients could resume their previous activity level within 1 month postoperatively. The JOA score significantly increased from 14.1±4.0 at baseline to 23.1±3.7 at the 1-year FU and 22.1±3.8 at the last FU. Similarly, there were significant improvements in the postoperative NRS and JOABPEQ scores. An additional surgery was performed in two patients (8%) during the FU period. Patients with degenerative scoliosis exhibited significantly poorer outcomes compared with those without this condition.

Conclusions

Transtubular endoscopic decompression can overcome certain technical challenges involved in the conventional procedures for LSEFL treatment; therefore, it can be recommended as a useful procedure for treating LSEFL. This procedure can provide some benefits to LSEFL patients and offer a well-illuminated surgical field and high surgical safety for the surgeon. However, the procedure should be carefully adapted for LSEFL patients with concomitant degenerative scoliosis.

Bi-portal Arthroscopic Spinal Surgery (BASS) with 30° arthroscopy for far lateral approach of L5-S1 - Technical note

Background context

Lumbar foraminal stenosis or extraforaminal stenosis is a common cause of spinal cord radiculopathy. Recently, several authors have introduced an endoscopy-based spinal surgery technique.

Purpose

The study aimed to introduce far lateral approach of biportal arthroscopic technique using 30° arthroscopy for foraminal decompression of L5-S1.

Study design

Technical note.

Patient sample

12 consecutive patients.

Outcome measures

The leg VAS with modified Macnab criteria was measured.

Result

The leg VAS improved from VAS 7.5 to 1.8.

Conclusion

Far lateral approach of BASS with 30° arthroscopy is an alternative method that can decompress foraminal stenosis minimally invasively.

Outcome of Decompression Alone for Foraminal/Extraforaminal Entrapment of L5 Nerve Root Through Wiltse Paraspinal Approach

STUDY DESIGN

Retrospective analysis.

OBJECTIVE OF THE STUDY

The objective of the study was to present the surgical outcome and analyze the prognostic factors for postoperative leg pain after posterior decompression alone for foraminal/extraforaminal L5 entrapment at L5-S1 segment (LSS).

SUMMARY OF BACKGROUND DATA

Disk extrusion, hypertrophy of facet joint, osteophyte of vertebral body, thickened lumbosacral ligament, and collapsed disk lead to form the lumbosacral tunnel which compresses the L5 exiting nerve root. There are few reports discussing the outcome and prognostic factors of posterior decompression alone.

MATERIALS AND METHODS

One hundred two consecutive patients underwent posterior decompressive surgery through Wiltse approach for foraminal/extraforaminal entrapment at LSS, performed by 2 surgeons. Demography and preoperative radiograph were analyzed for 6 parameters: age, pathology, disk height, relative disk height ratio, depth of L5 vertebrae within the pelvis, and coronal wedging angle of the segment. Clinical outcomes were assessed by the Visual Analog Scale score for back and leg pain, Oswestry Disability Index, and modified Macnab criteria. The incidence of medications of anticonvulsants, opioids, epidural nerve root block and revisional surgery at index level were also examined.

RESULTS

This study included 93 patients. The mean follow-up period was 40.6±19.7 months. Thirty-six patients had disk herniation and 57 had stenosis. Preoperative Visual Analog Scale score and Oswestry Disability Index significantly improved at the final follow-up. On the basis of the modified Macnab criteria, 83% of the patients had good outcomes at follow-up. The mean duration of the medications of anticonvulsants or opioids is 27.2±37.4 days (0-210 d). 5 patients (5.4%) were reoperated. Relative disk height ratio <0.8 was associated with worsening of postoperative leg pain (P<0.01).

CONCLUSIONS

Decompression as the only method for foraminal/extraforminal lesion of LSS through Wiltse paraspinal approach provided good clinical results. A large difference of disk height between standing and supine positions is associated with poor clinical outcomes.

Radiographic Assessment on Magnetic Resonance Imaging after Percutaneous Endoscopic Lumbar Foraminotomy

Percutaneous endoscopic lumbar foraminotomy (ELF) is a novel minimally invasive technique used to treat lumbar foraminal stenosis. However, the validity of foraminal decompression based on quantitative assessment using magnetic resonance imaging (MRI) has not yet been established. The objective of this study was to investigate the radiographic efficiency of ELF using MRI. Radiographic changes of neuroforamen were measured based on pre- and postoperative MRI findings. Images were blindly analyzed by two observers for foraminal stenosis grade and foraminal dimensions. The intraclass correlation coefficient (ICC) and k statistic were calculated to determine interobserver agreement. Thirty-five patients with 40 neuroforamen were evaluated. The mean visual analog scale (VAS) score improved from 8.4 to 2.1, and the mean Oswestry disability index (ODI) improved from 65.9 to 19.2. Overall, 91.4% of the patients achieved good or excellent outcomes. The mean grade of foraminal stenosis significantly improved from 2.63 to 0.68. There were significant increases in the mean foraminal area (FA) from 50.05 to 92.03 mm², in mean foraminal height (FH) from 11.36 to 13.47 mm, in mean superior foraminal width (SFW) from 6.43 to 9.27 mm, and in mean middle foraminal width (MFW) from 1.47 to 78 mm (P < 0.001). Interobserver agreements for preoperative and postoperative measurements were good to excellent with the exception of SFW. In conclusion, foraminal dimensions and grades of foraminal stenosis significantly improved after ELF. These findings may enhance the clinical relevance of endoscopic lumbar foraminal decompression.

Correlation between MRI Grading System and Surgical Findings for Lumbar Foraminal Stenosis

OBJECTIVE

Magnetic resonance imaging (MRI) grading systems using sagittal images are useful for evaluation of lumbar foraminal stenosis. We evaluated whether such a grading system is useful as a diagnostic tool for surgery.

METHODS

Between July 2014 and June 2015, 99 consecutive patients underwent unilateral lumbar foraminotomy for lumbar foraminal stenosis. Surgically confirmed foraminal stenosis and the contralateral, asymptomatic neuroforamen were assessed based on a 4-point MRI grading system. Two experienced researchers independently evaluated the MR sagittal images. Interobserver agreement and intraobserver agreement were analyzed using κ statistics.

RESULTS

The mean age of patients (54 women, 45 men) was 62.5 years. A total of 101 levels (202 neuroforamens) were evaluated. MRI grades for operated neuroforamens were as follows: Grade 0 in 0.99%, Grade 1 in 5.28%, Grade 2 in 14.85%, and Grade 3 in 78.88%. Interobserver agreement was moderate for operated neuroforamens (κ=0.511) and good for asymptomatic neuroforamens (κ=0.696). Intraobserver agreement by reader 1 for operated neuroforamens was good (κ=0.776) and that for asymptomatic neuroforamens was very good (κ=0.831). In terms of lumbar level, interobserver agreement for L5-S1 (κ=0.313, fair) was relatively lower than the other level (κ=0.804, very good).

CONCLUSION

MRI grading system for lumbar foraminal stenosis is thought to be useful as a diagnostic tool for surgery in the lumbar spine; however, it is less reliable for symptomatic L5-S1 foraminal stenosis than for other levels. Thus, various clinical factors as well as the MRI grading system are required for surgical decision-making.

Direct Tubular Lumbar Microdiscectomy for Far Lateral Disc Herniation: A Modified Approach

OBJECTIVE

The concept of minimally invasive tubular discectomy is based on precise placement of the retractor over the surgical target to minimize collateral tissue trauma. For far lateral disc herniation, the junction between the pars and the transverse process has generally been adopted as the target for facilitating early nerve root exposure; however, this may limit access to the disc space and increase the risks of iatrogenic neuralgia. An alternative approach to help address these issues involving docking the retractor caudally directly over the disc space with the aid of a microscope is here proposed. The purpose of this study was to evaluate the safety and efficacy of such an approach.

METHODS

Nineteen patients in whom the modified approach was performed over a 35-month period were identified. Direct access to the disc space was attained by directing the retractor against the lateral margin of the facet joint and following the inferior transverse process medially towards the foramen with minimal exposure of the nerve root. Clinical outcomes were assessed by the Oswestry Disability Index, visual analogue scale scores for leg and back pain, Short Form 36 physical functioning (SF36-PF) and bodily pain (SF36-BP) scores and sciatica bothersomeness and frequency indexes (SBI & SFI) and obtained from a prospective patient database. Follow-up data in the first 6 months were compared with preoperative baseline data.

RESULTS

All procedures were successfully completed with the modified approach. Contained disc herniation without sequestrated fragments was found in all but four cases. No perioperative complications or reoperation were recorded and no postoperative dysesthesia was noted. Clinically significant reductions in mean Oswestry Disability Index (32; 95% CI, 21-43) and visual analogue scale scores for leg pain (38 mm; 95% CI, 23-54 mm) and back pain (35 mm; 95% CI, 21-48 mm) scores were noted in the first 6 months. Significant improvements in SF36-PF (40; 95% CI, 30-51) and SF36-BP (35; 95% CI, 26-43), SBI (9; 95% CI, 6-11) and SFI (11; 95% CI, 8-13) were also recorded.

CONCLUSIONS

A modified direct tubular approach is safe and effective for treating far lateral lumbar disc herniation. Our early results suggest that this approach helps safeguard adequate decompression and reduce the risk of postoperative dysesthesia.

The surgery and early postoperative radicular pain in cases with multifocal lumbar disc herniation

Persistence of postoperative radicular pain after surgery for multifocal disc herniation (MFDH) is a clinical problem. This study aims to evaluate the effects of a combined treatment approach compared with unilateral stabilization on early postoperative radicular pain in patients with MFDH.Age, sex, level of operation, clinical findings, and radicular pain visual analogue scale (VAS) scores before surgery in the early postoperative period and at 3 months after surgery were retrospectively reviewed for 20 cases of multifocal lumbar disc herniation. The combined approach (translaminar and far lateral) was used for 13 cases. Seven cases underwent transforaminal lumbar interbody fusion (TLIF) and unilateral transpedicular stabilization following total facetectomy.The mean age of the sample was 49.4 ± 10.1 years and the female-to-male ratio was 8:12. The mean VAS scores for radicular pain in cases treated with the combined approach were 8.2, 4.07, and 2.3 in the preoperative and early postoperative periods and 3 months after surgery, respectively. The mean score for radicular pain improved by 50.4% in the early postoperative period and by 72% in the late postoperative period. The mean VAS scores for radicular pain in cases who underwent TLIF and unilateral stabilization after facetectomy were 8.4, 2.1, and 1.4 in the preoperative and early postoperative periods and 3 months after surgery, respectively. The mean VAS score for radicular pain improved by 75% in the early postoperative period and by 83.3% in the late postoperative period.The combined approach is an effective alternative in cases with MFDH. TLIF and unilateral segmental stabilization provide substantial decompression and eliminate mechanical compression by conserving the height of the intervertebral foramen in the event that sufficient decompression is unable to obtain. We suggest that elimination of chemical mediators, particularly those causing pain in the dorsal ganglion, contributes to the absence of early radicular pain.

Microsurgical Foraminotomy via Wiltse Paraspinal Approach for Foraminal or Extraforaminal Stenosis at L5-S1 Level : Risk Factor Analysis for Poor Outcome

Objective

The purpose of this study was to present the outcome of the microsurgical foraminotomy via Wiltse paraspinal approach for foraminal or extraforaminal (FEF) stenosis at L5–S1 level. We investigated risk factors associated with poor outcome of microsurgical foraminotomy at L5–S1 level.

Methods

We analyzed 21 patients who underwent the microsurgical foraminotomy for FEF stenosis at L5–S1 level. To investigate risk factors associated with poor outcome, patients were classified into two groups (success and failure in foraminotomy). Clinical outcomes were assessed by the visual analogue scale (VAS) scores of back and leg pain and Oswestry disability index (ODI). Radiographic parameters including existence of spondylolisthesis, existence and degree of coronal wedging, disc height, foramen height, segmental lordotic angle (SLA) on neutral and dynamic view, segmental range of motion, and global lumbar lordotic angle were investigated.

Results

Postoperative VAS score and ODI improved after foraminotomy. However, there were 7 patients (33%) who had persistent or recurrent leg pain. SLA on neutral and extension radiographic films were significantly associated with the failure in foraminotomy (p<0.05). Receiver-operating characteristics curve analysis revealed the optimal cut-off values of SLA on neutral and extension radiographic films for predicting failure in foraminotomy were 17.3° and 24°s, respectively.

Conclusion

Microsurgical foraminotomy for FEF stenosis at L5–S1 level can provide good clinical outcomes in selected patients. Poor outcomes were associated with large SLA on preoperative neutral (>17.3°) and extension radiographic films (>24°).

Three-Years Outcome of Microdiscectomy via Paramedian Approach for Lumbar Foraminal or Extraforaminal Disc Herniations in Elderly Patients over 65 Years Old

OBJECTIVE

Lumbar foraminal or extraforaminal disc herniations (FEFDH) have unusual clinical features and higher incidence in elderly patients compared to usual intraspinal canal disc herniations. We evaluated the efficacy of microdiscectomy via paramedian approach for lumbar FEFDH in elderly patients over the age of 65.

METHODS

Retrospective study was performed in 68 patients over the age of 65 (23 male and 45 female patients; 71.46±3.87 years) who underwent microdiscectomy via paramedian approach for unilateral lumbar FEFDH causing sciatica. The radiological factors including degree of slippage, presence of instability, disc height, and degree of disc degeneration; pain and functional status by the means of visual analogue scale score, Oswestry Disability Index score, and Macnab classification were analyzed preoperatively and during the postoperative follow-up period of 3 years to evaluate the efficacy of the surgical treatment.

RESULTS

Pain and functional status improved according to short- and long-term follow-up evaluations after surgery. Radiological changes following surgery, which can be understood as structural deteriorations and deformations, did not represent patient condition. Nine patients underwent additional surgery due to sustained or recurring leg pain of aggravation of back pain, and fusion surgery was required for 3 patients. Degree of preoperative slippage was the only statistically significant factor related to additional surgery (p<0.05).

CONCLUSION

Microdiscectomy via paramedian approach for FEFDH may be a good surgical alternative in elderly patients. Radiological changes after surgery did not show a concordance with patients' actual functional status. The excessive preoperative slippage tended to lead to unfavorable result after surgery and was associated with additional surgery.

Transforaminal lumbar interbody fusion using one diagonal fusion cage with unilateral pedicle screw fixation for treatment of massive lumbar disc herniation

BACKGROUND

Large lumbar or lumbosacral (LS) disc herniations usually expand from the paramedian space to the neuroforamen and compress both the transversing (lower) and the exiting (upper) nerve roots, thus leading to bi-radicular symptoms. Bi-radicular involvement is a statistically significant risk factor for poor outcome in patients presenting with far lateral or foraminal disc herniation after facet preserving microdecompression. There is evidence showing that patients suffering from large lumbar disc herniations treated with interbody fusion have significant superior results in comparison with those who received a simple discectomy. We report our experiences on managing large LS disc herniation with bi-radicular symptoms by transforaminal lumbar interbody fusion (TLIF) using one diagonal fusion cage with unilateral pedicle screw/rod fixation.

MATERIALS AND METHODS

Twenty-three patients who suffered from single level lumbar or LS disc herniation with bi-radicular symptoms treated with unilateral decompression and TLIF using one diagonal fusion cage with ipsilateral pedicle screw/rod fixation operated between January 2005 and December 2009, were included in this study. Operation time and blood loss were recorded. The pain and disability status were pre- and postoperatively evaluated by the visual analog score (VAS) and Oswestry Disability Index (ODI). Interbody bony fusion was detected by routine radiographs and computed tomography scan. Adjacent segment degeneration was detected by routine radiographs and magnetic resonance imaging examination. Overall outcomes were categorized according to modified Macnab classification.

RESULTS

The patients were followed up for an average of 44.7 months. Pain relief in the VAS and improvement of the ODI were significant after surgery and at final followup. No severe complications occurred during hospital stay. Interbody bony fusion was achieved in every case. No cage retropulsion was observed, while 3 cases experienced cage subsidence. Adjacent segment degeneration occurred at 3 discs cephalic to the fusion segment at followup. No patients underwent revised surgery. Overall outcome was excellent in 5 patients (21.7%), good in 13 (56.5%), fine in 4 (17.5%), and poor in 1 (4.3%).

CONCLUSIONS

TLIF using one cage with ipsilateral pedicle screw/rod fixation is an effective treatment option for massive lumbar or LS disc herniation with bi-radicular involvement.

Navigated Transtubular Extraforaminal Decompression of the L5 Nerve Root at the Lumbosacral Junction: Clinical Data, Radiographic Features, and Outcome Analysis

Purpose. Extraforaminal decompression of the L5 nerve root remains a challenge due to anatomic constraints, severe level-degeneration, and variable anatomy. The purpose of this study is to introduce the use of navigation for transmuscular transtubular decompression at the L5/S1 level and report on radiological features and clinical outcome. Methods. Ten patients who underwent a navigation-assisted extraforaminal decompression of the L5 nerve root were retrospectively analyzed. Results. Six patients had an extraforaminal herniated disc and four had a foraminal stenosis. The distance between the L5 transverse process and the para-articular notch of the sacrum was 12.1 mm in patients with a herniated disc and 8.1 mm in those with a foraminal stenosis. One patient had an early recurrence and another developed dysesthesia that resolved after 3 months. There was a significant improvement from preoperative to postoperative NRS with the results being sustainable at follow-up. ODI was also significantly improved after surgery. According to the Macnab grading scale, excellent or good outcomes were obtained in 8 patients and fair ones in 2. Conclusions. The navigated transmuscular transtubular approach to the lumbosacral junction allows for optimal placement of the retractor and excellent orientation particularly for foraminal stenosis or in cases of complex anatomy.

Postoperative Clinical Outcome and Risk Factors for Poor Outcome of Foraminal and Extraforaminal Lumbar Disc Herniation

OBJECTIVE

We evaluated postoperative outcomes in patients who have lumbar foraminal or extraforaminal disc herniation (FELDH) and suggested the risk factors for poor outcomes.

METHODS

A total of 234 patients were selected for this study. Pre- and post-operative Visual Analogue Scale (VAS) and Korean version Oswestry Disability Index (KODI) were evaluated and the changes of both score were calculated. Outcome was defined as excellent, good, fair, and poor based on Mcnab classification. The percentage of superior facetectomy was calculated by using the Maro-view 5.4 Picture Archiving Communication System (PACS).

RESULTS

Paramedian lumbar discectomy was performed in 180 patients and combined lumbar discectomy was performed in 54 patients. Paramedian lumbar discectomy group showed better outcome compared with combined discectomy group. p value of VAS change was 0.009 and KODI was 0.013. The average percentage of superior facetectomy was 33% (range, 0-79%) and it showed negative correlation with VAS and KODI changes (Pearson coefficient : -0.446 and -0.498, respectively). Excellent or good outcome cases (Group I) were 136 (58.1%) and fair or poor outcome cases (Group II) were 98 (41.9%). The percentage of superior facetectomy was 26.5% at Group I and 42.5% at Group II. There was significant difference in superior facetectomy percentage between Group I and II (p=0.000).

CONCLUSION

This study demonstrated that paramedian lumbar discectomy with preservation of facet joints is an effective and good procedure for FELDH. At least 60% of facet should be preserved for excellent or good outcomes.

In vivo dynamic changes of dimensions in the lumbar intervertebral foramen

BACKGROUND CONTEXT

Previous studies have reported position-dependent changes of the lumbar intervertebral foramen (LIVF) dimensions at different static flexion-extension postures. However, the changes of the LIVF dimensions during dynamic body motion have not been reported.

PURPOSE

The objective of this study was to investigate the in vivo dimensions of the LIVF during a dynamic weight-lifting activity.

STUDY DESIGN/SETTING

This was a retrospective study.

METHODS

Ten asymptomatic subjects were recruited for this study. Three-dimensional (3D) vertebral models of the lumbar segments from L2 to S1 were constructed for each subject using magnetic resonance images. The lumbar spine was then imaged using a dual fluoroscopic imaging system as the subject performed a dynamic weight-lifting activity from an upper body position of 45° to a maximal extension position. The in vivo positions of the vertebrae along the motion path were reproduced using the 3D vertebral models and the fluoroscopic images. The minimal area, height, and width of each LIVF during the dynamic body motion were analyzed.

RESULTS

The LIVF area and width monotonically decreased with lumbar extension at all levels except L5-S1 (p<.05). On average, the LIVF area decreased by 7.4±6.7%, 10.8±7.7%, and 10.0±8.0% at the L2-L3, L3-L4, and L4-L5 levels, respectively, from the flexion to the upright standing position, and by 6.4±5.0%, 7.7±7.4%, and 5.1±5.1%, respectively, from the upright standing to the extension position. The LIVF height remained relatively constant at all segments during the dynamic activity. The foramen area, height, and width of the L5-S1 remained relatively constant throughout the activity.

CONCLUSIONS

Human lumbar foramen dimensions show segment-dependent characteristics during the dynamic weight-lifting activity.

Extreme lateral interbody fusion for unilateral symptomatic vertical foraminal stenosis

PURPOSE

Asymmetric loss of disc height in adult deformity patients may lead to unilateral vertical foraminal stenosis and radiculopathy. The current study aimed to investigate whether restoration of foraminal height on the symptomatic side using extreme lateral interbody fusion (XLIF) would alleviate unilateral radiculopathy.

METHODS

In a retrospective study, patients with single-level unilateral vertical foraminal stenosis and corresponding radicular pain undergoing XLIF were included. Functional data (visual analog scale (VAS) for buttock, leg and back, as well as Oswestry Disability Index (ODI)) and radiographic measurements (bilateral foraminal height, disc height, segmental coronal Cobb angle and regional lumbar lordosis) were collected preoperatively, postoperatively and at the last follow-up.

RESULTS

Twenty-three patients were included, among whom 61 % had degenerative scoliosis. History of previous surgery at the level of index was present in 43 % of patients. Additional instrumentation was performed in 91 %. The foraminal height on the stenotic side was significantly increased postoperatively (p < 0.001), and remained significantly increased at the last follow-up of 11 ± 3.7 months (p < 0.001). Additionally, VAS buttock and leg on the stenotic side, VAS back and ODI were significantly improved postoperatively and at the last follow-up (p ≤ 0.001 for all parameters). The foraminal height on the stenotic side showed correlation with the VAS leg on the stenotic side, both postoperatively and the last follow-up (r = -0.590; p = 0.013, and r = -0.537; p = 0.022, respectively).

CONCLUSIONS

Single-level XLIF is an effective procedure for treatment of symptomatic unilateral foraminal stenosis leading to radiculopathy. In deformity patients with radicular pain caused by nerve compression at a single level, when not associated with other symptoms attributable to general scoliosis, treatment with single-level XLIF can result in short- and mid-term satisfactory outcome.