Effect of pure muscle retraction on multifidus injury and atrophy after posterior lumbar spine surgery with 24 weeks observation in a rabbit model

Biportal endoscopic lumbar discectomy surgery in patients with cauda equina syndrome caused by lumbar herniated intervertebral disc: a retrospective multi-center cohort study

BACKGROUND

Cauda equina syndrome (CES) is a severe neurological condition caused by significant compression of the cauda equina nerve roots. This study evaluates the efficacy of biportal endoscopic (BE) lumbar discectomy in treating CES caused by lumbar herniated intervertebral discs.

METHODS

This retrospective case series includes 32 CES patients treated with BE lumbar discectomy from March 2017 to July 2022. Patient demographics, surgical details, and outcomes were analyzed. Clinical outcomes were assessed using the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and EQ-5D scores at baseline, and at 3, 6, and 12 months postoperatively.

RESULTS

The mean age was 44.44 ± 13.70 years. The average duration from symptom onset to surgery was 44.81 ± 32.69 h. Significant improvements at 12 months were observed in VAS for back pain (5.00 ± 2.82 to 1.28 ± 1.63, p < 0.01) and leg pain (7.44 ± 1.79 to 1.16 ± 1.55, p < 0.01), ODI (58.25 ± 20.15 to 10.13 ± 14.54, p < 0.01), and EQ-5D (0.414 ± 0.175 to 0.859 ± 0.163, p < 0.01). Bladder and bowel symptom recovery rates were 86.7% and 85.0%, respectively. Mean operation time was 42.50 ± 17.91 min, with a hospital stay of 3.34 ± 2.59 days. Complications included incidental durotomy (6.3%) and facet joint injury (6.3%).

CONCLUSION

Biportal endoscopic spine surgery is a feasible and effective option for CES, providing significant decompression with minimal tissue damage and a low complication rate.

Restorative Neurostimulation of the Multifidus for Chronic Low Back Pain After Prior Lumbar Spinal Surgery: A Single-Center, Consecutive Case Series

OBJECTIVES

Restorative neurostimulation of the lumbar multifidus muscle is a novel therapy for chronic nonspecific low back pain (CLBP). Previous studies have excluded patients with prior lumbar surgery. In this study, we describe outcomes in patients with CLBP after prior lumbar surgery.

MATERIALS AND METHODS

This was a single-center, consecutive case series. The primary outcome measure was the change from baseline numeric rating score (NRS) for low back pain (LBP) and Oswestry Disability Index (ODI) in the first 12 months after treatment. Secondary outcomes were number of patients having minimal clinically important difference (MCID) in NRS and ODI scores, Short Assessment of Patient Satisfaction with their management, relationships between type of prior surgery and outcome, and incidence of adverse events.

RESULTS

The cohort comprised 26 patients (12 men; 14 women; mean age 56 years) who had their lumbar surgery a mean 6.9 years previously; 16 were followed up for 12 months and nine for >six months. One patient (3.6%) had a postoperative infection and required device removal. Both mean ODI and LBP NRS and their 95% CIs decreased serially from baseline 41.8 (36.5-46.5) to 29.3 (22.1-36.6) at six months and 28.1 (21.8-34.4) at 12 months (ODI), and from 6.4 (5.5-7.0), 3.8 (3.1-4.6) and 3.6 (2.5-4.7), respectively, for NRS. Patient levels of satisfaction with treatment were very high. MCIDs were observed in ten patients (40%) who experienced improvement in both their ODI (by >10) and NRS (by >2), and in ten patients who experienced improvement in one of these variables but not the other. The type of prior lumbar surgery did not influence outcomes. There were no device-related complications.

CONCLUSIONS

The early outcome profiles after restorative neurostimulation after lumbar spinal surgery are similar to those reported in patients without prior surgery. Further prospective clinical studies are required to establish the validity of these findings.

Changes in psoas and posterior paraspinal muscle morphology after standalone lateral lumbar interbody fusion: a quantitative MRI-based analysis

PURPOSE

Standalone lateral lumbar interbody fusion (SA-LLIF) without posterior instrumentation can be an alternative to 360° fusion in selected cases. This study aimed to investigate quantitative changes in psoas and paraspinal muscle morphology that occur on index levels after SA-LLIF.

METHODS

Patients undergoing single- or multi-level SA-LLIF at L2/3 to L4/5 who had preoperative and postoperative lumbar MRI scans, the latter performed between 3 and 18 months after surgery for any reason, were retrospectively included. Muscle measurements were performed of the psoas and posterior paraspinal muscles (PPM; erector spinae and multifidus) on index levels using manual segmentation and an automated pixel intensity threshold method to differentiate muscle from fat signal. Changes in the total cross-sectional area (TCSA), the functional cross-sectional area (FCSA), and the percentage of fat infiltration (FI) of these muscles were assessed.

RESULTS

A total of 67 patients (55.2% female, age 64.3 ± 10.6 years, BMI 26.9 ± 5.0 kg/m2) with 125 operated levels were included. Follow-up MRI scans were performed after an average of 8.7 ± 4.6 months, primarily for low back pain. Psoas muscle parameters did not change significantly, irrespective of the approach side. Among PPM parameters, the mean TCSA at L4/5 (+ 4.8 ± 12.4%; p = 0.013), and mean FI at L3/4 (+ 3.1 ± 6.5%; p = 0.002) and L4/5 (+ 3.0 ± 7.0%; p = 0.002) significantly increased.

CONCLUSION

Our study demonstrated that SA-LLIF did not alter psoas muscle morphology, underlining its minimally invasive nature. However, FI of PPM significantly increased over time despite the lack of direct tissue damage to posterior structures, suggesting a pain-mediated response and/or the result of segmental immobilization.

Unilateral biportal endoscopic lumbar interbody fusion enhanced the recovery of patients with the lumbar degenerative disease compared with the conventional posterior procedures: A systematic review and meta-analysis

Background

Minimally invasive endoscopic technique is an important component of Enhanced Recovery After Surgery (ERAS) protocol for neurosurgery. In recent years, unilateral biportal endoscopic lumbar interbody fusion (ULIF) has been used in the treatment of lumbar degenerative diseases (LDD). This study aims to investigate whether ULIF could enhance the recovery of patients with LDD compared with the conventional minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) or posterior lumbar interbody fusion (PLIF).

Methods

A comprehensive literature search was performed for relevant studies in PubMed, EMBASE, Web of Science, Cochrane Library database, China National Knowledge Internet, and Wanfang database. Surgical data, clinical outcomes, radiographic outcomes, and surgical complications were compared between patients with LDD who underwent ULIF and those who underwent conventional MI-TLIF or PLIF.

Results

Notably, 12 studies, comprising 981 patients with LDD, were included. Of these patients, 449 underwent ULIF and 532 patients (355 MI-TLIF and 177 PLIF) were treated with conventional procedures. There was no significant difference in the fusion rate, cage subsidence rate, and surgical complications between the ULIF group and the MI-TLIF or PLIF group. Compared with MI-TLIF, the ULIF group presented a significantly reduced estimated blood loss (EBL) (WMD, -106.00; 95% CI -140.99 to -71.10, P < 0.001) and shorter length of hospital stay (LOS) (WMD, -1.27; 95% CI -1.88 to -0.66, P < 0.001); better short-term improvement in ODI (WMD, -2.12; 95% CI -3.53 to -0.72, P = 0.003) and VAS score for back pain (VAS-BP) (WMD, -0.86; 95% CI -1.15 to -0.58, P < 0.001) at 1 month post-operatively. Compared with PLIF, the ULIF group presented a significantly reduced EBL (WMD, -149.22; 95% CI -284.98 to -13.47, P = 0.031) and shorter LOS (WMD, -4.40; 95% CI -8.04 to -0.75, P = 0.018); better short-term improvement in VAS-BP (WMD, -1.07; 95% CI -1.77 to -0.38, P = 0.002) and VAS score for leg pain (VAS-LP) (WMD, -0.40; 95% CI -0.72 to -0.08, P = 0.014) at 1-2 week post-operatively; enhanced short- and long-term improvement in ODI at 1 month post-operatively (WMD, -3.12; 95% CI -5.72 to -0.53, P = 0.018) and the final follow-up (WMD, -1.97; 95% CI -3.32 to -0.62, P = 0.004), respectively.

Conclusion

Compared with conventional MI-TLIF and PLIF, ULIF was associated with reduced EBL, shorter LOS, and comparable fusion rate as well as complication management. Compared with MI-TLIF, a better short-term improvement in VAS-BP and ODI was achieved by ULIF; compared with open PLIF, additional enhanced short-term improvement in VAS-LP and long-term improvement in ODI were observed in ULIF. ULIF could enhance the recovery of patients with LDD compared with conventional posterior procedures.

Systematic trial registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=230695, CRD42021230695.

The relationship between the degeneration and asymmetry of the lumbar multifidus and erector spinae muscles in patients with lumbar disc herniation with and without root compression

BACKGROUND

The determination of muscle pathologies in lumbar disc herniation (LDH) and other conditions with low back pain is important for understanding low back problems and determining appropriate treatment methods. In patients with lumbar disc herniation with radiculopathy, elucidating the effect of root compression on the severity of muscle degeneration may predict the importance of alleviating root compression. For this purpose, magnetic resonance imaging (MRI) was used to compare the degeneration and asymmetries of the lumbar musculus multifidus (MF) and lumbar musculus erector spinae (ES) muscles in patients with lumbar discopathy without root compression (radiculopathy) and in patients with lumbar discopathy with root compression (radiculopathy).

METHODS

The patients were examined in two groups: 56 patients with lumbar discopathy and no radiculopathy (Non-rad group) and 51 patients with lumbar discopathy and radiculopathy (Rad group). On axial MRI sections passing through the centre of the disc at the L3-S1 level, the asymmetry, cross-sectional area (CSA), fat infiltration, and total CSA (TCSA = MF + ES) of the MF and ES muscles were measured and compared.

RESULTS

No difference was seen between the groups with respect to the CSA values of the right and left MF and left ES, but a significant difference was found in the right ES CSA (p = 0.021). The CSA and TCSA of the MF and ES showed no asymmetry according to group. Severe fat infiltration of > 50% in the right and left MF and left ES was found in the Rad group at a higher rate than in the Non-rad group. Fat infiltration was significantly positively correlated with age, body mass index, and the duration of pain (p < 0.001, p < 0.001, p = 0.004, respectively).

CONCLUSIONS

The study results showed a correlation between LDH and paraspinal muscle degeneration, while no correlation was found with asymmetry. Severe (> 50%) fat infiltration is associated with root compression, and the severity of fat filtration increases in the presence of root compression. The development of more severe degeneration due to denervation associated with root compression plays a role in the emergence of this situation. Therefore, in patients with lumbar disc herniation with radiculopathy, it can be foreseen that to stop and correct severe fat infiltration and muscle degeneration, first, nerve root compression should be corrected with appropriate medical treatment methods, and in patients in whom there is no response, the pressure should be alleviated with appropriate surgical methods.

The Effect of Posterior Lumbar Spinal Surgery on Biomechanical Properties of Rat Paraspinal Muscles 13 Weeks After Surgery

STUDY DESIGN

Preclinical study in rodents.

OBJECTIVE

To investigate changes in biomechanical properties of paraspinal muscles following a posterior spinal surgery in an animal model.

SUMMARY OF BACKGROUND DATA

Posterior spine surgery damages paraspinal musculature per histological and imaging studies. The biomechanical effects of these changes are unknown.

METHODS

12 Sprague-Dawley rats were divided equally into sham and surgical injury (SI) groups. For sham, the skin and lumbodorsal fascia were incised at midline. For SI, the paraspinal muscles were detached from the vertebrae, per normal procedure. Thirteen weeks postsurgery, multifidus and longissimus biopsies at L1, L3, and L5 levels were harvested on the right. From each biopsy, three fibers and three to six bundles of fibers (∼10-20 fibers ensheathed in their extracellular matrix) were tested mechanically to measure their passive elastic modulus. The collagen content and fatty infiltration of each biopsy were also examined histologically by immunofluorescence staining. Nonparametric statistical methods were used with a 1.25% level of significance.

RESULTS

A total of 220 fibers and 279 bundles of fibers were tested. The elastic moduli of the multifidus and longissimus fibers and longissimus fiber bundles were not significantly different between the SI and sham groups. However, the elastic modulus of multifidus fiber bundles was significantly greater in the SI group compared to sham (SI median 82 kPa, range 23-284; sham median 38 kPa, range 23-50, P = 0.0004). The elastic modulus of multifidus fiber bundles in the SI group was not statistically different between spinal levels (P = 0.023). For histology, only collagen I deposition in multifidus was significantly greater in the SI group (median 20.8% vs. 5.8% for sham, P < 0.0001).

CONCLUSION

The surgical injury increased the passive stiffness of the multifidus fiber bundles. Increased collagen content in the extracellular matrix is the likely reason and these changes may be important in the postoperative compensation of the spine.Level of Evidence: N/A.

Paraspinal muscle pathophysiology associated with low back pain and spine degenerative disorders

Low back pain disorders affect more than 80% of adults in their lifetime and are the leading cause of global disability. The muscles attaching to the spine (ie, paraspinal muscles) are critical for proper spine health and play a crucial role in the functioning of the spine and whole body; however, reports of muscle dysfunction and insufficiency in chronic LBP (CLBP) patients are common. This article presents a review of the current understanding of the relationship between paraspinal muscle pathophysiology and spine-related disorders. Human literature demonstrates a clear association between altered muscle structure/function, most notably fatty infiltration and fibrosis, and low back pain disorders; other associations, including muscle cell atrophy and fiber type changes, are less clear. Animal literature then provides some mechanistic insight into the complex relationships, including initiating factors and time courses, between the spine and spine muscles under pathological conditions. It is apparent that spine pathology can directly lead to changes in the paraspinal muscle structure, function, and biology. It also appears that changes to the muscle structure and function can directly lead to changes in the spine (eg, deformity); however, this relationship is less well studied. Future work must focus on providing insight into possible mechanisms that regulate spine and paraspinal muscle health, as well as probing how muscle degeneration/dysfunction might be an initiating factor in the progression of spine pathology.

Alternatives to Traditional Pedicle Screws for Posterior Fixation of the Degenerative Lumbar Spine

BACKGROUND

Traditional pedicle screws are currently the gold standard to achieve stable 3-column fixation of the degenerative lumbar spine. However, there are cases in which pedicle screw fixation may not be ideal. Due to their starting point lateral to the pars interarticularis, pedicle screws require a relatively wide dissection along with a medialized trajectory directed toward the centrally located neural elements and prevertebral vasculature. In addition, low bone mineral density remains a major risk factor for pedicle screw loosening, pullout, and pseudarthrosis. The purpose of this article is to review the indications, advantages, disadvantages, and complications associated with posterior fixation techniques of the degenerative lumbar spine beyond the traditional pedicle screws.

METHODS

Comprehensive literature searches of the PubMed, Scopus, and Web of Science databases were performed for 5 methods of posterior spinal fixation, including (1) cortical bone trajectory (CBT) screws, (2) transfacet screws, (3) translaminar screws, (4) spinous process plates, and (5) fusion mass screws and hooks. Articles that had been published between January 1, 1990, and January 1, 2020, were considered. Non-English-language articles and studies involving fixation of the cervical or thoracic spine were excluded from our review.

RESULTS

After reviewing over 1,700 articles pertaining to CBT and non-pedicular fixation techniques, a total of 284 articles met our inclusion criteria. CBT and transfacet screws require less-extensive exposure and paraspinal muscle dissection compared with traditional pedicle screws and may therefore reduce blood loss, postoperative pain, and length of hospital stay. In addition, several methods of non-pedicular fixation such as translaminar and fusion mass screws have trajectories that are directed away from or posterior to the spinal canal, potentially decreasing the risk of neurologic injury. CBT, transfacet, and fusion mass screws can also be used as salvage techniques when traditional pedicle screw constructs fail.

CONCLUSIONS

CBT and non-pedicular fixation may be preferred in certain lumbar degenerative cases, particularly among patients with osteoporosis. Limitations of non-pedicular techniques include their reliance on intact posterior elements and the lack of 3-column fixation of the spine. As a result, transfacet and translaminar screws are infrequently used as the primary method of fixation. CBT, transfacet, and translaminar screws are effective in augmenting interbody fixation and have been shown to significantly improve fusion rates and clinical outcomes compared with stand-alone anterior lumbar interbody fusion.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A comparison of the bilateral decompression via unilateral approach versus conventional approach transforaminal lumbar interbody fusion for the treatment of lumbar degenerative disc disease in the elderly

Background

Bilateral decompression via unilateral approach (BDUA) is an effective surgical approach for treating lumbar degenerative diseases. However, no studies of prognosis, especially the recovery of the soft tissue, have reported using BDUA in an elderly population. The aims of these research were to investigate the early efficacy of the bilateral decompression via unilateral approach versus conventional approach transforaminal lumbar interbody fusion (TLIF) for the treatment of lumbar degenerative disc disease in the patients over 65 years of age, especially in the perioperative factors and the recovery of the soft tissue.

Methods

The clinical data from 61 aging patients with lumbar degenerative disease who received surgical treatment were retrospectively analyzed. 31 cases who received the lumbar interbody fusion surgery with bilateral decompression via unilateral approach (BDUA) were compared with 30 cases who received conventional approach transforaminal lumbar interbody fusion. The radiographic parameters were measured using X-ray including lumbar lordosis angle and fusion rate. Japanese Orthopedic Association (JOA), Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores were used to evaluate the clinical outcomes at different time points. Fatty degeneration ratio and area of muscle/vertebral body were used to detect recovery of soft tissue.

Results

The BDUA approach group was found to have significantly less intraoperative blood loss(p < 0.05) and postoperative drainage(p < 0.05) compared to conventional approach transforaminal lumbar interbody fusion group. Symptoms of spinal canal stenosis and nerve compression were significantly relieved postoperatively, as compared with the preoperative state. However, the opposite side had a lower rate of fatty degeneration (9.42 ± 3.17%) comparing to decompression side (11.68 ± 3.08%) (P < 0.05) six months after surgery in the BDUA group. While there were no significant differences (P > 0.05) in two sides of conventional transforaminal lumbar interbody fusion approach group six months after surgery.

Conclusions

Bilateral decompression via unilateral approach (BDUA) is able to reduce the intraoperative and postoperative body fluid loss in the elderly. The opposite side of decompression in BDUA shows less fatty degeneration in 6 months, which indicates better recovery of the soft tissue of the aging patients.

Ascorbic Acid Attenuates Multifidus Muscles Injury and Atrophy After Posterior Lumbar Spine Surgery by Suppressing Inflammation and Oxidative Stress in a Rat Model

STUDY DESIGN

A rat model of multifidus muscles injury and atrophy after posterior lumbar spine surgery.

OBJECTIVE

We determined the effect of ascorbic acid (AA) on the postoperative multifidus muscles in rat model.

SUMMARY OF BACKGROUND DATA

Previous studies show oxidative stress and inflammation are two main molecular mechanisms in multifidus muscle injury and atrophy after posterior lumbar surgery. AA may have a protective effect in postoperative multifidus muscles.

METHODS

Rats were divided into sham surgery, control surgery, and surgery plus AA groups. Multifidus muscles of the control and AA groups were excised from the osseous structures. The muscles were retracted continuously for 2 hours. In the sham and AA groups, AA was administered via oral gavage daily in the first week. In each group, the oxidative stress was evaluated by measuring malondialdehyde (MDA) and Total superoxide dismutase (T-SOD). The inflammation, fat degeneration, or fibrosis of multifidus muscle were evaluated by quantitative real-time polymerase chain reaction (q-PCR), histology, or immunohistochemical analysis.

RESULTS

T-SOD activity was significantly lower in the control group than that in the AA group in the first week. MDA levels were significantly higher in the AA group. Interleukin-6 and tumor necrosis factor-α in multifidus muscles also showed significant differences when treated with AA. The inflammation score on histology was significantly lower in the AA group postoperatively in the first week. In the long run, marker genes for fibrosis and fat degeneration, and fibrosis and fat degeneration scores, were significantly lower in the AA than the control group on days 14 and 28 postoperatively.

CONCLUSION

In conclusion, AA attenuated the oxidative stress and inflammation response in the postoperative multifidus muscles, and remarkable differences were observed from the histological assessment and related marker genes expression. Our results provided important insight into the anti-inflammatory and anti-oxidative effects of AA in the postoperative multifidus muscles.

LEVEL OF EVIDENCE

N/A.

Investigation of the passive mechanical properties of spine muscles following disruption of the thoracolumbar fascia and erector spinae aponeurosis, as well as facet injury in a rat

BACKGROUND CONTEXT

Muscle tissue is known to remodel in response to changes to its mechanical environment. Alterations in passive mechanical properties of muscles can influence spine stiffness and stability.

PURPOSE

This study aimed to determine whether passive muscle elastic moduli and passive muscle stresses increased 28 days following mechanical disruption of the thoracolumbar fascia and erector spinae aponeurosis, and injury induced by facet joint compression.

STUDY DESIGN

Male Sprague Dawley rats were randomly assigned to three groups (Incision n=8; Injury n=8; and Control n=6).

METHODS

The thoracolumbar fascia and erector spinae aponeurosis were incised in the Incision and Injury groups to expose the left L5-L6 facet joint. In the Injury group, this facet was additionally compressed for three minutes to induce facet injury and cartilage degeneration. Twenty-eight days after surgery, rats were sacrificed and muscle samples were harvested from lumbar and thoracic erector spinae and multifidus for mechanical testing.

RESULTS

Histologic staining revealed mild cartilage degeneration and boney remodeling in the Injury group. However, the hypotheses that either (1) disruption of the thoracolumbar fascia and erector spinae aponeurosis (Incision group) or (2) the addition of facet compression (Injury group) would increase the passive elastic modulus and stress of surrounding muscles were rejected. There was no effect of surgery (Incision or Injury) on the passive elastic modulus (p=.6597). Passive muscle stresses were also not different at any sarcomere length between surgical groups (p>.7043).

CONCLUSION

Disruption of the thoracolumbar fascia and erector spinae aponeurosis and mild facet damage do not lead to measurable changes in passive muscle mechanical properties within 28 days. These findings contribute to our understanding of how spine muscles are affected by injury and fundamental aspects of the initial stages of spine surgery.

Comparison of minimally invasive and open transforaminal lumbar interbody fusion in the treatment of single segmental lumbar spondylolisthesis: minimum two-year follow up

Background

Compare the efficacy and safety of minimally invasive and open transforaminal lumbar interbody fusion (TLIF) in the treatment of single segmental lumbar spondylolisthesis.

Methods

From 2010-01 to 2015-10, in total, 167 patients with single segmental spondylolisthesis treated by TLIF were included, 79 cases in minimally invasive TLIF (MI-TLIF) group and 88 cases in open TLIF group. The peri-operative parameters of operative time, estimated blood loss and length of postoperative hospital stay was recorded, as well as complications. Visual Analogue Scale (VAS) of low back pain and leg pain, and Oswestry Disability Index (ODI) were used to assess the pain and functional outcomes at pre-operatively, 3 months/1 year/2 years/5 years after operation. The radiographic parameters of posterior height of the intervertebral space and segmental lordosis were measured too.

Results

No significantly difference was found at baseline characteristic data of age, gender ratio, the percentage of degenerative and isthmic spondylolisthesis, the percentage of slip, and segmental distribution between MI-TLIF and open TLIF groups. MI-TLIF group had less estimated intra-operative blood loss (163.7±49.6 mL) than open TLIF group (243.3±70.2 mL, P<0.001) and had shorter post-operative hospital stay (5.8±1.4 days) than open TLIF group (7.3±2.9 days, P<0.001). Both MI-TLIF and open TLIF can significantly reduce the VAS of low back pain, VAS of leg pain, ODI, and improve the posterior height of the intervertebral space and segmental lordosis, but no significantly difference was found of them between two groups.

Conclusions

Our study suggests that MI-TLIF is a safe and effective choice in the treatment of lower grade lumbar spondylolisthesis (grade II or less), and it has advantages of less blood loss, postoperative hospital stay when compared to open TLIF.