L5 S1 Research Articles

Comparative Analysis of Full Endoscopic Interlaminar Lumbar Discectomy and Lumbar Microdiscectomy

Study Design: Retrospective clinical study. Objectives: The aim is to assess and contrast the results of full endoscopic lumbar discectomy (FELD) and lumbar microdiscectomy (LMD) for L5–S1 disc herniation, with a specific emphasis on postoperative pain reduction and surgical effectiveness. Background: Although minimally invasive spine operations are becoming more popular, there is still little research on the comparative effectiveness of FELD and LMD. Materials and Methods: The research had a total of 50 patients who received surgical intervention for L5–S1 disc herniation, with 25 patients getting full endoscopic interlaminar discectomy and the other 25 patients undergoing LMD. Clinical outcomes were assessed using the Visual Analog Scale for low back and leg pain, collected preoperatively and at the end of 1 week, 3 months, and 6 months postsurgery. Patient satisfaction was evaluated using Odoms criteria at the same intervals. Results: The study included 50 patients (26 men, 24 women), with a mean age of 51.11 ± 13.76 years. The groups had no significant differences in demographic data. Back and leg pain Visual Analog Scale scores decreased more significantly in the FELD group after 1 week of surgery (P < 0.001), although the declines at 3 months and 6 months were not significantly different between the two groups. According to Odoms criteria, patient satisfaction was favorable in both groups and significantly better in the FELD group than in the LMD group at 1 week postoperatively [excellent in 20 patients (80%) in the FELD group vs 9 patients (36%) in the LMD group (P = 0.025)]. However, patient satisfaction at 3 months and 6 months did not differ between the groups. Conclusion: This study demonstrates that FELD offers significant early postoperative advantages over LMD at the L5–S1 level when compared with pain and satisfaction scales. Level of Evidence Level III.

A case of consecutive four-level lumbar spondylolysis and spondylolisthesis

This rare and unusual case is about a 54-year-old female, who has pars fractures involving consecutive four-level bilateral spondylolysis and spondylolisthesis. Due to the increasing intensity with lumbar instability, the patient had severe low back pain. For diagnosis, dynamic X-ray, magnetic resonance, 3D tomography were performed, and bilateral L2-3-4-5 pars fracture and L3-4 spondylolisthesis were observed. This case was treated surgically byspinal canal decompression at L3-4, L4-5 and L5-S1, posterior lumbar interbody fusion at L4–5 and L5–S1, and pedicle screw fixation at L2–S1. The lower back pain disappeared after the surgery.

L5–S1 Spondylolisthesis: What Has Changed in 20 Years? A Review of Key Issues in Comparison with Personal Experience

The very first issue of the Russian Journal of Spine Surgery (2004;(1):39–46) published an article entitled “Surgical Treatment for L5 Spondylolisthesis with Transpedicular Fixators”. Twenty years later, the authors analyzed changes in approaches to surgical treatment of spondylolisthesis, taking into account the experience in surgical treatment of this pathology gained at the N.N. Priorov National Medical Research Center of Traumatology and Orthopaedics. The issues of classification, fixation methods, reduction, changes in sagittal balance, the possibility of using additive technologies and possible complications of surgical treatment are considered.In conclusion, it is noted that the development of surgical treatment methods, the study of biomechanical features, the introduction of additive technologies and much more enable improving the outcomes of spondylolisthesis treatment.

Free Vascularized Scapula tip Flap to L5—S1 Vertebral Defect After Chronic Infection Related to Interbody Fusion Cage: A Case Report

ABSTRACTSeptic nonunion after vertebral fusion can lead to significant patient disability. The management of septic nonunions usually involves surgical debridement, bone fixation, and antibiotic therapy. Particularly challenging is lumbosacral vertebral nonunions, which necessitate a difficult surgical approach. We present a novel approach using a scapula tip free flap through an intra‐abdominal approach to reconstruct a L5–S1 vertebral defect after a septic nonunion. Our patient, 31‐year‐old man, with no medical conditions, had a fusion of L5–S1 due to severe lower back pain secondary to isthmic spondylolysis and spondylolisthesis. Despite multiple attempts of surgical fusion, postoperatively the patient developed a septic nonunion. Following a modified DAIR, the nonunion was reconstructed with a scapula tip bone flap 4 × 3 × 2 cm. The subscapular vessels were anastomosed to the deep inferior epigastric vessels after an intra‐abdominal inset. The patient was discharged at 15 days postoperatively without any complications. At 1‐year follow‐up the patient is pain‐free, off opiate analgesia with radiological evidence of fusion between the scapula tip, L5 and the S1 vertebral body. This case report describes the use, for the first time, of a free scapula tip, to a lumbosacral spinal defect. The use of the free scapula tip flap may be considered for reconstruction of osseous spinal defects due to its long pedicle and the unique bone shape.

Fully Endoscopic Transforaminal Approach for L5–S1 Foraminal Stenosis: A Narrative Review

Lumbar foraminal stenosis (LFS) is a fairly common degenerative condition of the spine that can often occur in the L5–S1 segment. Traditional surgical approaches for LFS can be categorized into microscopic foraminotomy via the Wiltse approach and interbody fusion. Microscopic foraminotomy via the Wiltse approach was previously considered the gold standard for treating LFS. However, with advancements in endoscopic equipment and techniques, fully endoscopic foraminotomy through various approaches is now widely performed for the treatment of LFS. Among these approaches, endoscopic foraminotomy via the transforaminal approach offers many advantages, but difficulties may be encountered when there are anatomical barriers, which are often present in the L5–S1 segment. This study aimed to explore the overall clinical outcomes and complications of transforaminal endoscopic lumbar foraminotomy, as well as the challenges specific to the L5–S1 segment and techniques to overcome them.

Growth rate of a giant Tarlov (perineural) cyst with intrapelvic extension

Background and importanceGiant Tarlov cysts (GTCs) are perineural cysts and their presacral intrapelvic extension are extremely rare entities. We present a case of GTC with intrapelvic extension who has preoperative Magnetic Resonance Imaging (MRI) follow-ups of 12 years, and we demonstrate the annual growth rate and the time-size correlation of a GTC.MethodsCase report.Clinical presentationA 37-year-old woman was admitted with left gluteal pain radiating to left foot, left leg numbness, progressed over 12 years. On MRI, starting from the L5–S1 level, a giant Tarlov cyst with an atypical configuration, is observed. The patient had a known sacral Tarlov cyst, first discovered on MRI obtained 12 years before the surgery. She had 6 consecutive MRI follow-ups in 12 years preoperatively. The cysts diameters have been measured and the growth rate was estimated. We showed for the first time that presented GTC grows in in both Sagittal Diagonal (SD) and Sagittal Craniocaudal (SC) diameters over time with overall annual growth rates, 7.671% for RGR_SD and 6.237% for RGR_SC.ConclusionWhen the time-size correlation is observed, it becomes evident that the GTSs’ growing speed increases over the years because of minimal resistance in the intrapelvic cavity. Early surgery may be considered to prevent rapid growth in the intrapelvic cavity and to reduce possible complications of the giant cyst.

Technical Considerations and Avoiding Complications in Interlaminar Endoscopic Lumbar Discectomy

The fully endoscopic technique has become the most effective and safest option for the treatment of lumbar disc herniation. Specifically, the interlaminar approach, which was first described at the beginning of the 21st century, is used for the treatment of L4–5 and L5–S1 intracanal disc herniation. Learning protocolized maneuvers facilitates reproducibility and increases the safety of the procedure. The description of the main maneuvers in this article aims to reduce complications and the learning curve with their widespread implementation.

Preoperative and follow-up variations of psoas major muscle are related to S1 screw loosening in patients with degenerative lumbar spinal stenosis

BackgroundIt was reported the paraspinal muscle played an important role in spinal stability. The preoperative paraspinal muscle was related to S1 screw loosening. But the relationship between preoperative and postoperative change of psoas major muscle (PS) and S1 pedicle screw loosening in degenerative lumbar spinal stenosis (DLSS) patients has not been reported. This study investigated the effects of preoperative and follow-up variations in the psoas major muscle (PS) on the first sacral vertebra (S1) screw loosening in patients with DLSS.Methods212 patients with DLSS who underwent lumbar surgery were included. The patients were divided into the S1 screw loosening group and the S1 screw non-loosening group. Muscle parameters were measured preoperatively and at last follow-up magnetic resonance imaging. A logistic regression analysis was performed to investigate the risk factors for S1 screw loosening.ResultsThe S1 screw loosening rate was 36.32% (77/212). The relative total cross-sectional areas and relative functional cross-sectional areas (rfCSAs) of the PS at L2–S1 were significantly higher after surgery. The increased rfCSA values of the PS at L3–S1 in the S1 screw non-loosening group were significantly higher than those in the S1 screw loosening group. The regression analysis showed male, lower CT value of L1 and longer segment fusion were independent risk factors for S1 screw loosening, and postoperative hypertrophy of the PS was a protective factor for S1 screw loosening.ConclusionsCompared to the preoperative muscle, the PS size increased and fatty infiltration decreased after surgery from L2–3 to L5–S1 in patients with DLSS after short-segment lumbar fusion surgery. Postoperative hypertrophy of the PS might be considered as a protective factor for S1 screw loosening. MRI morphometric parameters and postoperative selected exercise of PS for DLSS patients after posterior lumbar fusion surgery might contribute to improvement of surgical outcome.

Single-Stage Lateral Anterior-to-Psoas Interbody Fusion and Facet Screws as a Treatment for L5–S1 Adjacent Segment Disease in a Patient With a Long-Segment Construct

Objective: Adjacent segment disease (ASD) occurs in 9% of patients with long-segment lumbar spine fusion and results from the transmission of a greater degree of stress to the segments cranial and caudal to a fused segment. The treatment of symptomatic ASD typically involves extending fusion to the involved segment. Revision and extension of posterior instrumentation bears the disadvantage of involving the exposure and modification of old hardware. Lateral interbody fusion cannot be performed at L5/S1 due to the iliac crest. Anterior lumbar interbody fusion typically still requires flipping the patient to augment the construct posteriorly. Here, we present a method to treat L5/S1 ASD using single-position anterior-to-psoas (ATP) interbody fusion combined with facet screw instrumentation.Methods: An 80-year-old man, who had undergone L2-5 fusion 27 years ago, presented with persistent lower back pain and gait dysfunction with imaging findings of L5/S1 spondylosis and ASD. Under intraoperative computed tomography navigation, left L5/S1 ATP interbody fusion was performed with simultaneous L5/S1 percutaneous facet screw fixation. Results: The abdominal incision was 4.0 cm and the single posterior incision was 1.5 cm long. Blood loss was lower than 10 mL, and the procedure lasted for less than 1.5 hours. The patient was discharged to rehabilitation after 3 days.Conclusion: ATP interbody fusion enabled the placement of an interbody device with a large footprint to promote fusion and reduce the risk of subsidence and pseudoarthrosis. The combined use of interbody fusion and facet screws obviates the need to link to the previous construct.

Zoster-associated Limb Paralysis: Clinical and Electrophysiological Data of 15 Cases with Segmental Zoster Paresis with the Literature Review

ABSTRACT Background: Herpes zoster (HZ) is a viral disease characterized by skin eruptions and pain in specific dermatomes. Focal motor weakness that appears in the segment of skin eruptions is a rare complication of this infection. Because of the difficulty in clinically diagnosing thoracic or upper cervical motor weakness and due to the pain that causes overlooking of weakness, the true incidence of this complication is not known. In this study, we want to review the clinical presentation of segmental zoster paresis and also discuss electrophysiological findings with the involvement of nerve, plexus parts, or spinal roots. Methods: Electromyography records were examined retrospectively from 2010 to 2023 for patients who had HZ-associated limb paresis. Clinical data were reviewed and abstracted, and patients whose clinical limb weakness and sensory deficits conformed to the distribution of peripheral nerve (s) or spinal root and whose electrodiagnostic evaluation corroborated the localization, were included in the series. Results: Fifteen patients were included in our study. Ten of them were men and five of them were women. Paresis and neuropathic pain are the main complaints. In all patients, the distribution of paresis was consistent with the area of skin eruptions. C8–T1 in the upper extremity and L5–S1 in the lower extremity are the most commonly involved segments. Electrophysiological findings showed radicular involvement in three cases, brachial plexus in six cases, ulnar nerve in one case, sciatic nerve in two cases, and fibular nerve in three cases. Axonopathy is the main detected pathology in all cases. Conclusion: Segmental zoster paresis is a rare complication of cutaneous zona zoster and it affects different nerve segments. Clinicians should be aware of clinical and electrophysiological findings of this disease for the appropriate management of the patients.

Preliminary Outcomes of Patients with Lumbar Disc Herniation Undergoing Unilateral Biportal Endoscopic Spine Surgery: A Single-Center Retrospective Study in Vietnam

Objective: Unilateral biportal endoscopic (UBE) treatment for lumbar disc herniation (LDH) is an advanced surgical procedure that has recently gained popularity. Numerous reports from developed countries have demonstrated the effectiveness of this minimally invasive technique. We evaluated the initial outcomes of UBE at a healthcare facility with limited resources.Methods: Clinical and radiographic data of 82 patients with LDH treated between July 2022 and June 2023 using UBE discectomy techniques, including the ipsilateral interlaminar approach, contralateral sublaminar approach, and paraspinal approach, were reviewed. Outcomes were analyzed in terms of the modified MacNab criteria, Japanese Orthopaedic Association (JOA) score, and visual analogue scale (VAS), with a mean follow-up of 3.1 months.Results: At the final follow-up, the mean VAS for low back pain improved from 4.5±1.0 to 1.2±0.4 and the VAS for leg pain improved from 7.8±0.9 to 1.6±0.5. The mean JOA score improved from 13.5±2.4 to 24.2±2.1. The modified MacNab criteria were excellent in 56 patients (68.3%), good in 22 (26.9%), and fair in 4 (4.8%). In total, 106 levels of LDH were treated. L4–5 disc herniation was performed in 55 patients (51.9%), L5–S1 in 36 (34.0%), L3–4 in 8 (7.5%), L2–3 in 6 (5.7%), and L1–2 in 1 (0.9%). The ipsilateral interlaminar approach was performed in 93 patients (87.7%), the contralateral sublaminar approach in 7 (6.6%), and the paraspinal approach in 6 (5.7%). Operative time significantly improved after performing 20 cases. In the early stage (1–20 cases), the operation time per level was 102.0±28.2 min, while in the next stage (21–82 cases) it was 78.1±20.4 minutes. No serious complications, including cauda equine syndrome or root palsy, were observed. Three patients had dural tears (2.8%), and 1 had epidural hematoma (0.9%).Conclusion: UBE discectomy may be performed safely and effectively for the treatment of LDH in limited-resource settings.

A Retrospective Observational Study to Evaluate Adjacent Segmental Degenerative Change with the Dynesys-Transition-Optima Instrumentation System.

This study evaluates the impact of hybrid dynamic stabilization using the Dynesys-Transition-Optima (DTO) system on adjacent segment disease (ASD) in lumbar spinal stenosis patients with spondylolisthesis. From 2012 to 2020, 115 patients underwent DTO stabilization at a single center by a single neurosurgeon. After exclusions for lack of specific stabilization and incomplete data, 31 patients were analyzed. Follow-up was conducted at 6, 12, and 24 months postoperatively, assessing disc height, listhesis distance, and angular motion changes at L2-L3, L3-L4, and L5-S1. L3-L4 segment (the index level), demonstrated a delayed increase in listhesis distance, contrasting with earlier changes in other segments. At two years, L3-L4 exhibited less increase in listhesis distance and less disc height reduction compared to L2-L3 and L5-S1. Notably, the L3-L4 segment showed a significant reduction in angular motion change over two years. In conclusion, while ASD was not significantly prevented, the study indicates minor and delayed degeneration at the index level. The L3-L4 segment experienced reduced angular change in motion, suggesting a potential benefit of DTO in stabilizing this specific segment.

Percutaneous endoscopic transforaminal vs. interlaminar discectomy for L5–S1 lumbar disc herniation: a retrospective propensity score matching study

ObjectivePercutaneous endoscopic lumbar discectomy (PELD) is a safe and effective minimally invasive surgery for treating lumbar disc herniation (LDH); however, the comparative clinical efficacy of percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID) in treating L5–S1 LDH remains unclear. This study compared the clinical advantages of PEID and PETD for treating L5–S1 LDH.MethodsThis was a single-centre retrospective study analysing clinical data from 120 patients with L5–S1 LDH between February 2016 and May 2020. Propensity score matching (PSM) was used to adjust for imbalanced confounding variables between the two groups. Perioperative data were recorded, and clinical outcomes, including functional scores and imaging data, were compared between groups. Functional scores included visual analogue scale (VAS) for back and leg pain, Oswestry disability index (ODI), and modified MacNab criteria. Imaging data included disc height index (DHI), ratio of greyscale (RVG), and range of motion (ROM) of the responsible segment.ResultsAfter PSM, 78 patients were included in the study, and all covariates were well balanced between the two groups. In the matched patients, the PEID group showed significantly shorter surgical time (65.41 ± 5.05 vs. 84.08 ± 5.12 min) and lower frequency of fluoroscopy (2.93 ± 0.63 vs. 11.56 ± 1.54) compared with the PETD group (P < 0.001). There were no statistically significant differences in intraoperative blood loss, postoperative hospital stay, total incision length, and incidence of complications between the two groups (P > 0.05). After surgery, both groups showed significant improvement in back and leg pain based on VAS and ODI scores (P < 0.05). There were no statistically significant differences in clinical functional scores and imaging data between the two groups at various time points after surgery (P > 0.05). According to the modified MacNab criteria, the excellent and good rates in the PEID group and PETD group were 91.89% and 89.19%, respectively, with no statistically significant difference (P > 0.05).ConclusionPEID and PETD have similar clinical efficacy in treating L5–S1 disc herniation. However, PEID is superior to PETD in reducing operation time and frequency of fluoroscopy.

Exploring the impact of mild-to-moderate foraminal stenosis at L5−S1 on clinical outcomes following L4−5 posterior lumbar interbody fusion

BACKGROUND CONTEXTPatients scheduled for L4−5 PLIF often have FS at L5-S1. However, data on the clinical and radiographic outcomes of cases with mild-to-moderate L5−S1 FS are lacking, which may affect clinical outcomes or require additional surgery after L4−5 fusion. PURPOSETo evaluate the clinical and radiographic outcomes of L4−5 PLIF in patients with and without mild-to-moderate L5−S1 FS, with a primary focus on the association between L5−S1 FS and postoperative clinical outcomes including back pain, leg pain, and scores on the oswestry disability index (ODI) and EuroQol 5-dimension (EQ-5D). STUDY DESIGNRetrospective comparative study. PATIENT SAMPLEA retrospective review of patients who underwent L4−5 PLIF from 2014 to 2018. The patients were divided according to the presence of mild-to-moderate FS at L5−S1. OUTCOME MEASURESClinical assessment included the pain visual analog scale (VAS), ODI, and EQ-5D score. Radiographic assessments included spinopelvic parameters and grades for central and foraminal stenosis. METHODSClinical outcomes were assessed using validated outcome measures at preoperative, 6-month, 12-month, and 36-month follow-up visits. Radiographic evaluations were performed using preoperative and postoperative radiographs. Foraminal stenosis was assessed qualitatively using MRI with a grading system from none to severe and quantitatively by measuring changes in the foraminal area on CT. RESULTSAmong 186 patients, 55 were categorized as the FS group and 131 as the non-FS group. The FS group was older (p=0.039) and had more severe central stenosis at L5−S1 (p=0.007) as well as more severe FS at both L4−5 and L5−S1 (both p<0.001). Preoperative disc height (p<0.001), C7-S1 sagittal vertical axis (p=0.003), lumbar lordosis (p=0.005), and pelvic incidence–lumbar lordosis mismatch (p=0.026) were more aggravated in the FS group. The FS group showed inferior clinical outcomes at the final follow-up in terms of back pain (p=.010) and ODI score (p=.003). CONCLUSIONThe presence of mild-to-moderate FS at L5–S1 was associated with more aggravated sagittal balance in terms of smaller preoperative disc height, larger sagittal vertical axis, smaller lumbar lordosis, and larger pelvic incidence–lumbar lordosis mismatch. Patients with L5−S1 FS also had poorer clinical outcomes including back pain and ODI score after L4−5 PLIF. Patients with L5−S1 FS need to be carefully examined before L4−5 fusion considering their adverse outcomes due to underlying degenerative changes.

Posterior lumbar interbody fusion using single PEEK cage without pedicle screw fixation for lumbar disc herniation; Initial experience in Menoufia University Hospital

BackgroundLumbar discectomy has successful initial clinical outcome; its long-term success rate decreases to 40–80% due to chronic low back pain and recurrent disc herniation.ObjectiveTo evaluate the clinical results of Posterior Lumbar Interbody Fusion with a single unilateral stand-alone PEEK (Poly-Ether-Ether-Ketone) cage without pedicle screw fixation for single level lumbar disc herniation.MethodsA retrospective study of 40 patients (24 men and 16 women) with lumbar disc herniation, was conducted in the period from January 2016 through January 2021. The follow-up continued till December 2021. All patients suffered from single level lumbar disc herniation and were treated with Posterior Lumbar Interbody Fusion with a single unilateral stand-alone PEEK cage without pedicle screw fixation.ResultsThe affected levels were L2–3 in 2 cases, L3–4 in 8 cases, L4–5 in 18 cases and L5–S1 in 12 cases. On 18th month follow-up, significant decrease in leg pain, LBP and ODI scores was detected (p < 0.001).ConclusionsThis technique produced satisfying clinical enhancement in residual LBP, accepted radiological outcome such as maintaining the proper intervertebral disc space and prevention of recurrent disc herniation.

Fusion Length Requiring Spinopelvic Fixation in Lumbosacral Fusion with Anterior Column Support at L5-S1: Assessment of Fusion Status Using Computed Tomography.

The lumbosacral (LS) junction has a higher nonunion rate than other lumbar segments, especially in long-level fusion. Nonunion at L5-S1 would result in low back pain, spinal imbalance, and poor surgical outcomes. Although anterior column support at L5-S1 has been recommended to prevent nonunion in long-level LS fusion, fusion length requiring additional spinopelvic fixation (SPF) in LS fusion with anterior column support at L5-S1 has not been evaluated thoroughly. This study aimed to determine the number of fused levels requiring SPF in LS fusion with anterior column support at L5-S1 by assessing the interbody fusion status using computed tomography (CT) depending on the fusion length. Patients who underwent instrumented LS fusion with L5-S1 interbody fusion without additional augmentation and CT > 1 year postoperatively were included. The fusion rates were assessed based on the number of fused segments. Patients were divided into two groups depending on the L5-S1 interbody fusion status: those with union vs. those with nonunion. Binary logistic regression analyses were performed to identify risk factors for LS junctional nonunion. Fusion rates of L5-S1 interbody fusion were 94.9%, 90.3%, 80.0%, 50.0%, 52.6%, and 43.5% for fusion of 1, 2, 3, 4, 5, and ≥ 6 levels, respectively. The number of spinal levels fused ≥ 4 (p < 0.001), low preoperative bone mineral density (BMD; adjusted odds ratio [aOR], 0.667; p = 0.035), and postoperative pelvic incidence (PI) - lumbar lordosis (LL) mismatch (aOR, 1.034; p = 0.040) were identified as significant risk factors for nonunion of L5-S1 interbody fusion according to the multivariate logistic regression analysis. Exhibiting ≥ 4 fused spinal levels, low preoperative BMD, and large postoperative PI-LL mismatch were identified as independent risk factors for nonunion of anterior column support at L5-S1 in LS fusion without additional fixation. Therefore, SPF should be considered in LS fusion extending to or above L2 to prevent LS junctional nonunion.

Traumatic L5-S1 spondylolisthesis: A case report

Purpose: Here, we report the diagnosis and management of a patient with a traumatic lumbosacral spondylolisthesis, a rare clinical entity that is characterized by unilateral or bilateral facet dislocations causing displacement at the level of the fifth lumbar vertebra in relation to the sacrum. &#x0D; Case presentation: We report a case of a traumatic L5-S1 unilateral lumbosacral dislocation. Based on the preoperative CT and MRI findings, the patient sustained a right-side unilateral L5–S1 subluxation with an L5 right inferior articular process fracture, a torn anterior longitudinal ligament and posterior ligamentous complex, and L5-S1 disc protrusion. Decompression, reduction with L4, L5, S1 pedicular screw fixation, L5-S1 disc excision, and interbody cage insertion were performed. The patient had an uneventful recovery and returned to his previous activities 6 months after surgery.

Effect of neuromuscular electrical stimulation therapy using the StimaWELL 120MTRS system on erector spinae morphology in patients with chronic low back pain

ObjectiveChronic low-back pain (CLBP) is the leading cause of disability globally. CLBP is associated with a decrease in cross-sectional area (CSA) and an increase in fat infiltration (FI) of the lumbar paraspinal muscles, such as erector spinae (ES). Neuromuscular electrical stimulation (NMES) therapy showed promising outcomes in the treatment of CLBP, but its impact on ES morphology is unknown. Therefore, this study aimed to compare the effect of two NMES protocols on ES CSA and FI in a cohort of patients with CLBP.MethodsTwenty participants with CLBP (aged 18–60 years old) were randomized into the phasic (n = 11) or the combined (n = 9) protocol groups. They completed a 10-week (20 sessions) NMES therapy using the StimaWELL 120MTRS device. Magnetic resonance imaging (MRI) examinations were acquired at baseline and post-intervention to assess ES CSA and FI at all spinal levels (e.g., L1–L2 to L5–S1). Statistical analyses were conducted to assess the effect of the intervention on ES morphology irrespective of groups, and between groups.ResultsIrrespective of groups, participants showed a decrease in left ES CSA (p = 0.005) at L2–L3 and left ES FI at L5–S1 (p = 0.040). We also observed a greater decrease in ES FI in the combined protocol compared to the phasic protocol on the right side at L3–L4 (p = 0.029) and L4–L5 (p = 0.015). No other changes in ES CSA or FI were observed (p &amp;gt; 0.05).ConclusionNMES therapy demonstrated minimal effect on ES morphology in patients with CLBP. Further research is needed to extend and confirm our findings.

Effects of dynamic and rigid implantation on biomechanical characteristics of different sagittal alignment lumbar after single- or double-level spinal fixations: a finite-element modeling study

BackgroundAlthough it is critical to understand the accelerated degeneration of adjacent segments after fusion, the biomechanical properties of the spine have not been thoroughly studied after various fusion techniques. This study investigates whether four Roussouly’s sagittal alignment morphotypes have different biomechanical characteristics after different single- or double-level spinal fixations.MethodsThe parametric finite element (FE) models of Roussouly’s type (1–4) were developed based on the radiological data of 625 Chinese community population. The four Roussouly's type models were reassembled into four fusion models: single-level L4–5 Coflex fixation model, single-level L4–5 Fusion (pedicle screw fixation) model, double-level Coflex (L4–5) + Fusion (L5–S1) model, and double-level Fusion (L4–5) + Fusion (L4–5) model. A pure moment of 7.5 Nm was applied to simulate the physiological activities of flexion, extension, lateral bending and axial rotation.ResultsBoth single-level and double-level spinal fixation had the greatest effect on lumbar range of motion, disc pressure, and annulus fibrosis stress in flexion, followed by lateral bending, extension, and axial rotation. In all models, the upper adjacent segment was the most influenced by the implantation and bore the most compensation from the fixed segment. For Type 2 lumbar, the L4–L5 Coflex effectively reduced the disc pressure and annulus fibrosis stress in adjacent segments compared to the L4–L5 Fusion. Similarly, the L4–L5 Coflex offered considerable advantages in preserving the biomechanical properties of adjacent segments for Type 1 lumbar. For Type 4 lumbar, the L4–L5 Coflex did not have superiority over the L4–L5 Fusion, resulting in a greater increase in range of motion at adjacent segments in flexion and extension. The difference between the two fixations was not apparent in Type 3 lumbar. Compared to the single-level Fusion, the changes in motion and mechanics of the lumbar increased after both the double-level Coflex + Fusion and Fusion + Fusion fixations, while the differences between two double-level fixation methods on adjacent segments of the four lumbar models were similar to that of the single-level fixation.ConclusionType 3 and Type 4 lumbar have good compensatory ability and therefore allow for a wider range of surgical options, whereas surgical options for small lordotic Type 1 and Type 2 lumbar are more limited and severe.

Intraoperative Anteropulsion of an Interbody Fusion Cage During Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Case Report

Expandable cages are very commonly used during minimally invasive lumbar interbody fusion surgery for better restoration of sagittal alignment. We present a rare event of intraoperative expandable cage anteropulsion into the retroperitoneal space. To date, several cases of cage migration have been reported. However, ours is the first case of intraoperative anterior cage migration during minimally invasive lumbar fusion. Herein, we present a case of 70-year-old female planned for minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for grade II L5–S1 lytic spondylolisthesis. There was an unnoticed anterior longitudinal ligament rupture during the cage expansion manoeuvre. Cage dislodgment was noticed intraoperatively. This was managed by compression of the interbody site posteriorly and insertion of another snugly fitting bullet cage, followed by anterior retroperitoneal exploration in the same setting to retrieve the migrated cage. The patient’s postoperative course was satisfactory. At a 1-year follow-up, patient was ambulatory and asymptomatic. Follow-up imaging showed bony fusion and no signs of implant failure. Expandable TLIF cages can cause iatrogenic release of the anterior longitudinal ligament during expansion. Surgeons must be aware of this rare complication, which can result in anterior cage migration.