Long-term outcome of fusion for degenerative disc disease in the lumbar spine

Annulus Fibrosus Injury Induces Acute Neuroinflammation and Chronic Glial Response in Dorsal Root Ganglion and Spinal Cord-An In Vivo Rat Discogenic Pain Model

Chronic painful intervertebral disc (IVD) degeneration (i.e., discogenic pain) is a major source of global disability needing improved knowledge on multiple-tissue interactions and how they progress in order improve treatment strategies. This study used an in vivo rat annulus fibrosus (AF) injury-driven discogenic pain model to investigate the acute and chronic changes in IVD degeneration and spinal inflammation, as well as sensitization, inflammation, and remodeling in dorsal root ganglion (DRG) and spinal cord (SC) dorsal horn. AF injury induced moderate IVD degeneration with acute and broad spinal inflammation that progressed to DRG to SC changes within days and weeks, respectively. Specifically, AF injury elevated macrophages in the spine (CD68) and DRGs (Iba1) that peaked at 3 days post-injury, and increased microglia (Iba1) in SC that peaked at 2 weeks post-injury. AF injury also triggered glial responses with elevated GFAP in DRGs and SC at least 8 weeks post-injury. Spinal CD68 and SC neuropeptide Substance P both remained elevated at 8 weeks, suggesting that slow and incomplete IVD healing provides a chronic source of inflammation with continued SC sensitization. We conclude that AF injury-driven IVD degeneration induces acute spinal, DRG, and SC inflammatory crosstalk with sustained glial responses in both DRGs and SC, leading to chronic SC sensitization and neural plasticity. The known association of these markers with neuropathic pain suggests that therapeutic strategies for discogenic pain need to target both spinal and nervous systems, with early strategies managing acute inflammatory processes, and late strategies targeting chronic IVD inflammation, SC sensitization, and remodeling.

Analysis of global research hotspots and trends in immune cells in intervertebral disc degeneration: A bibliometric study

Intervertebral disc degeneration is an important pathological basis for spinal degenerative diseases. The imbalance of the immune microenvironment and the involvement of immune cells has been shown to lead to nucleus pulposus cells death. This article presents a bibliometric analysis of studies on immune cells in IDD in order to clarify the current status and hotspots. We searched the WOSCC, Scopus and PubMed databases from 01/01/2001 to 08/03/2023. We analyzed and visualized the content using software such as Citespace, Vosviewer and the bibliometrix. This study found that the number of annual publications is increasing year on year. The journal study found that Spine had the highest number of articles and citations. The country/regions analysis showed that China had the highest number of publications, the USA had the highest number of citations and total link strength. The institutional analysis found that Shanghai Jiao Tong University and Huazhong University of Science Technology had the highest number of publications, Tokai University had the highest citations, and the University of Bern had the highest total link strength. Sakai D and Risbud MV had the highest number of publications. Sakai D had the highest total link strength, and Risbud MV had the highest number of citations. The results of the keyword analysis suggested that the current research hotspots and future directions continue to be the study of the mechanisms of immune cells in IDD, the therapeutic role of immune cells in IDD and the role of immune cells in tissue engineering for IDD.

A Decreasing National Trend in Lumbar Disc Arthroplasty

STUDY DESIGN

Retrospective National Database Study.

OBJECTIVES

The aim of this study was to investigate the national trend of lumbar disc arthroplasty (LDA) utilization from 2005 to 2017.

METHODS

Patients undergoing primary LDA between 2005 and 2017 were identified in the National Inpatient Sample (NIS) database. Year of the procedure, demographic, socioeconomic, hospital, and cost parameters were analyzed. The data was weighted using provided weights from the NIS database to generate national estimates of LDA procedure incidence. Lastly, we assessed the incidence of cervical disc arthroplasty (CDA) between 2005 and 2017 to serve as a historical comparison.

RESULTS

An estimated 20 460 patients underwent primary LDA in the United States between 2005 and 2017. There was an initial decrease in LDA procedures between 2005 and 2006 and then a plateau between 2006 and 2009. From 2010 to 2013, there was a significant year-over-year decrease in annual LDA procedures performed, followed by a second plateau from 2014 to 2017. Overall, LDA procedures decreased 82% from 2005 to 2017. Over the same time, the annual incidence of CDA utilization increased 795% from approximately 474 procedures in 2005 to 4245 procedures in 2017 (P < .01).

CONCLUSIONS

Lumbar disc arthroplasty utilization decreased 82% from 2005 to 2017, with a significant decrease in the rate of utilization noted after 2010. The utilization of LDA to treat selected degenerative lumbar conditions has not paralleled the increasing popularity of CDA, and, in fact, has demonstrated a nearly opposite utilization trend.

Association between immediate postoperative hypoalbuminemia and surgical site infection after posterior lumbar fusion surgery

PURPOSE

In this study, we intended to investigate the association between immediate postoperative hypoalbuminemia and surgical site infection (SSI), and determine a threshold value for postoperative hypoalbuminemia that can assist in risk stratification in patients after posterior lumbar fusion surgery.

METHODS

From January 2017 to December 2021, 466 consecutive patients who underwent posterior lumbar fusion surgery were selected to analyze the relationship between immediate postoperative hypoalbuminemia and SSI. Multivariate logistic regression analysis was performed to identify the independent risk factors of SSI and postoperative hypoalbuminemia. Receiver Operating Characteristic (ROC) analysis was used to determine the optimal value for postoperative hypoalbuminemia, and subsequent grouping was based on the identified threshold.

RESULTS

Of the total 466 patients, 25 patients (5.4%) developed SSI after surgery, and lower postoperative albumin (OR: 0.716, 95% CI: 0.611-0.840, p < 0.001) was independently associated with SSI. ROC analysis showed that the cutoff value of postoperative hypoalbuminemia was 32 g/L with a sensitivity of 0.760, specificity of 0.844, and a Youden index of 0.604. Postoperative SSI was more common in patients with postoperative hypoalbuminemia than in those without (21.6% vs. 1.6%, p < 0.001). Age, gender and operative duration were found to be independent predictors of postoperative hypoalbuminemia.

CONCLUSIONS

This study showed that immediate postoperative hypoalbuminemia was an independent risk factor for the development of SSI in patients who underwent posterior lumbar fusion. Even in patients with a normal preoperative serum albumin level, there was an increased risk of SSI when the postoperative albumin within 24 h was < 32 g/L.

Application of platelet-rich plasma in spinal surgery

With the aging of the population and changes in lifestyle, the incidence of spine-related diseases is increasing, which has become a major global public health problem; this results in a huge economic burden on the family and society. Spinal diseases and complications can lead to loss of motor, sensory, and autonomic functions. Therefore, it is necessary to identify effective treatment strategies. Currently, the treatment of spine-related diseases includes conservative, surgical, and minimally invasive interventional therapies. However, these treatment methods have several drawbacks such as drug tolerance and dependence, adjacent spondylosis, secondary surgery, infection, nerve injury, dural rupture, nonunion, and pseudoarthrosis. Further, it is more challenging to promote the regeneration of the interstitial disc and restore its biomechanical properties. Therefore, clinicians urgently need to identify methods that can limit disease progression or cure diseases at the etiological level. Platelet-rich plasma (PRP), a platelet-rich form of plasma extracted from venous blood, is a blood-derived product. Alpha granules contain a large number of cytokines, such as platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor, platelet factor 4 (PF-4), insulin-like growth factor-1 (IGF-1), and transforming growth factor-β (TGF-β). These growth factors allow stem cell proliferation and angiogenesis, promote bone regeneration, improve the local microenvironment, and enhance tissue regeneration capacity and functional recovery. This review describes the application of PRP in the treatment of spine-related diseases and discusses the clinical application of PRP in spinal surgery.

Are Octogenarians at Higher Risk of Complications After Elective Lumbar Spinal Fusion Surgery? Analysis of a Cohort of 7880 Patients From the Kaiser Permanente Spine Registry

STUDY DESIGN

A retrospective cohort study with chart review.

OBJECTIVE

To determine if there is a difference in risk of adverse outcomes following elective posterior instrumented lumbar spinal fusions for patients aged 80 years and above compared with patients aged 50 to 79 years.

SUMMARY OF BACKGROUND DATA

Patients aged 80 years and above are undergoing elective lumbar spinal fusion surgery in increasing numbers. There are conflicting data on the risks of intraoperative and postoperative complications in these patients.

MATERIALS AND METHODS

Patients aged 80 years and above were compared with 50 to 79 years (reference group) using time-dependent multivariable Cox proportional hazards regression with a competing risk of death for longitudinal outcomes and multivariable logistic regression for binary outcomes. Outcome measures used were: (1) intraoperative complications (durotomy), (2) postoperative complications: 30-day outcomes (pneumonia); 90-day outcomes (deep vein thrombosis, pulmonary embolism, emergency room visits, readmission, reoperations, and mortality); and two-year outcomes (reoperations and mortality).

RESULTS

The cohort consisted of 7880 patients who underwent primary elective posterior instrumented lumbar spinal fusion (L1-S1) for degenerative disk disease or spondylolisthesis. This was subdivided into 596 patients were aged 80 years and above and 7284 patients aged 50 to 79. After adjustment, patients aged 80 years and above had a higher likelihood of durotomy [odds ratio (OR)=1.43, 95% confidence interval (CI)=1.02-2.02] and 30-day pneumonia (OR=1.81, 95% CI=1.01-3.23). However, there was a lower risk of reoperation within two years of the index procedure (hazard ratio=0.69, 95% CI=0.48-0.99). No differences were observed for mortality, readmissions, emergency room visits, pulmonary embolism, or deep vein thrombosis.

CONCLUSIONS

In a cohort of 7880 elective posterior instrumented lumbar fusion patients for degenerative disk disease or spondylolisthesis, we did not observe any significant risks of adverse events between patients aged 80 years and above and those aged 50 to 79 except for higher durotomies and 30-day pneumonia in the former. We believe octogenarians can safely undergo lumbar fusions, but proper preoperative screening is necessary to reduce the risks of 30-day pneumonia.

Postoperative Opioid Use Following Single-Level Transforaminal Lumbar Interbody Fusion Compared with Posterolateral Lumbar Fusion

OBJECTIVE

To compare postoperative opioid morphine milligram equivalents (MME) prescriptions for opioid-naïve patients undergoing single-level transforaminal lumbar interbody fusion (TLIF) versus posterolateral lumbar fusion (PLF) and total postoperative MME prescribed based on operative duration.

METHODS

Patients undergoing single-level TLIF or PLF from September 2017 to June 2020 were identified from a single institution. Patients were first grouped based on procedure type (TLIF or PLF) and subsequently regrouped based on median operative duration. Statistical tests compared patient demographics and opioid prescription data between groups. Multivariate regressions were performed to control for demographics, operative time, and procedure type.

RESULTS

Of 345 patients undergoing single-level PLF or TLIF, 174 (50.4%) were opioid-naïve; 101 opioid-naïve patients (58.0%) underwent PLF and 73 (42.0%) underwent TLIF. Patients undergoing TLIF received more opioid prescriptions (1.99 vs. 1.26, P < 0.001) and total MME (91.2 vs. 66.8, P = 0.002). After regrouping patients based on operative duration, independent of procedure type, there were no differences in postoperative opioid prescriptions, and Spearman rank correlation coefficient between total MME and operative duration was r = 0.014. Multivariate analysis identified TLIF as an independent predictor of increased postoperative opioid prescriptions (β = 0.64, P < 0.001), prescribers (β = 0.49, P = 0.003), and MME (β = 24.4, P = 0.030).

CONCLUSIONS

Opioid-naïve patients undergoing single-level TLIF receive a greater number of postoperative opioids than patients undergoing single-level PLF, and TLIF was an independent predictor of increased postoperative opioid prescribers, prescribers, and MME. There were no differences in postoperative opioid prescriptions when assessing patients based on operative duration.

The Impact of Perioperative Multimodal Pain Management on Postoperative Outcomes in Patients (Aged 75 and Older) Undergoing Short-Segment Lumbar Fusion Surgery

Background

Due to the presence of multimorbidity and polypharmacy, patients aged 75 and older are at a higher risk for postoperative adverse events after lumbar fusion surgery. More effective enhanced recovery pathway is needed for these patients. Pain control is a crucial part of perioperative management. The objective of this study is to determine the impact of multimodal pain management on pain control, opioid consumption, and other outcomes.

Methods

This is a retrospective review of a prospective collected database. Consecutive patients who underwent elective posterior lumbar fusion surgery (PLF) from October 2017 to April 2021 in our hospital were reviewed. Perioperative multimodal pain management (PMPM) group (from January 2019 to April 2021) in which patients received multimodal analgesia was case-matched to the control group (from October 2017 to December 2018) in which patients were treated under the conventional patient-controlled analgesia (PCA) method. Postoperative visual analogue scale (VAS), opioid consumption, complications within 3 months, and other outcomes were collected and compared between groups.

Results

A total of 122 consecutive patients (aged 75 and older) were included in the PMPM group and compared with previous 122 patients. The PMPM group had a lower maximal VAS score (3.0 ± 1.7 vs. 3.7 ± 2.0, p < 0.001) and frequency of additional opioid consumption (6.6% vs. 19.7%, p=0.001) on POD3 than the control group. The rates of postoperative complications were lower in the PMPM group compared with the control group (25% vs. 49%, p=0.006) during a 3-month follow-up period.

Conclusions

This study demonstrates that the PMPM protocol is effective in pain control and reducing additional opioid consumption when compared with conventional analgesia, even for patients aged 75 and older. Moreover, these improvements occur with a lower incidence of postoperative complications within three months after PLF surgery.

Open-label placebo for chronic low back pain: a 5-year follow-up

ABSTRACT

Long-term follow-up of patients treated with open-label placebo (OLP) are nonexistent. In this article, we report a 5-year follow-up of a 3-week OLP randomized controlled trial (RCT) in patients with chronic low back pain. We recontacted the participants of original RCT and reassessed their pain, disability, and use of pain medication. We obtained follow-up data from 55 participants (82% of those who took OLP during the parent RCT), with a mean elapsed time between the end of the 3 weeks placebo trial and the follow-up interview of 55 months (SD = 7.85). We found significant reductions in both pain and disability between the baseline assessment immediately before the 3 weeks trial with placebo pills and the original trial endpoint (P < 0.00001 for the 2 primary outcomes of pain and disability). At the 5-year follow-up, we found no significant differences in either outcome between original trial endpoint and follow-up. Improvements persisted after 5 years and were accompanied by substantial reductions compared with baseline in the use of pain medication (from 87% to 38%), comprising analgesics (from 80% to 31%), antidepressants (from 24% to 11%), and benzodiazepines (from 15% to 5%). By contrast, the use of alternative approaches to pain management increased (from 18% to 29%). Although the reduction in pain and medication is comparable with the improvements that occurred in the original study, a major limitation of this long-term follow-up is the absence of controls for spontaneous improvement and new cointerventions. Nonetheless, our data suggest that reductions in pain and disability after OLP may be long lasting.

Study of the Feasibility of Conventional MR Images and Magnetic Resonance (MR)/Ultra-Short Echo Time (UTE) Technique in the Evaluation of Lumbar Disc Degeneration in the Axial Plane

The advantage and value of magnetic resonance (MR)-ultra-short echo time (UTE) technique in the displaying the structures of degenerative intervertebral discs were observed through evaluating the lumbar disc degeneration in the axial plane by conventional MR image and MR-UTE technique. A total of 160 examinees screened by inclusion and exclusion criteria were enrolled, and a total of 800 intervertebral disks were involved, and the degree of intervertebral disc degeneration was classified by conventional MR image classification method. After the first echo image of MR-UTE technique was integrated with the contour, the image entered UTE cartilage endplate, fibrous ring and osseous endplate. The integrity of the intervertebral disc from the above and below the intervertebral disc and the correlation of the structural endplate with the integrities of cartilage endplate, fibrous ring and osseous endplate under double echo sequence were analyzed, and the correlation analysis of the two categorical variables was conducted using rank correlation analysis. Under the MR-UTE sequence, there was no statistical significant difference in structural integrity constituent ratio (intact structure only on one side, incomplete structure on both side) between the non-low back pain group and the low back pain group (P > 0.05), the proportion of complete structure disappearance was lowest, and the proportion of partial structure disappearance was highest; there was a significant difference in the structural integrity of fibrous ring between the non-low back pain group and the low back pain group (P < 0.05), there was a statistical significant difference in structural integrity of fibrous rings between the two groups (P < 0.05); there was a statistical significant difference in pain degree between the partial structure disappearance group and the complete structure disappearance group (P < 0.05). There was no significant difference in pain degree between the groups (intact structure only on one side and incomplete structure on both side); conventional MR images showed no significant difference in the intervertebral disc degeneration degree between the non-low back pain group and low back pain group (P > 0.05), and the intervertebral disc degeneration degree had no significant correlation with the lower back pain. MR-UTE sequence and T2WI sequence showed that there was a correlation between different intervertebral disc degeneration degrees and the structural integrity distributions of cartilage endplate, osseous endplate and fibrous rings in two groups of patients with or without low back pain (P < 0.05). Whether low back pain exists or not has little effect on the intervertebral disc degeneration degree on T2WI. MR-UTE double echo sequence scan reveals that the intervertebral disc degeneration degree is positively related to the integrity and integrity distribution of cartilage endplate, fibrous ring and bone endplate.

Clinical implications of lumbar developmental spinal stenosis on back pain, radicular leg pain, and disability

AIMS

To study the associations of lumbar developmental spinal stenosis (DSS) with low back pain (LBP), radicular leg pain, and disability.

METHODS

This was a cross-sectional study of 2,206 subjects along with L1-S1 axial and sagittal MRI. Clinical and radiological information regarding their demographics, workload, smoking habits, anteroposterior (AP) vertebral canal diameter, spondylolisthesis, and MRI changes were evaluated. Mann-Whitney U tests and chi-squared tests were conducted to search for differences between subjects with and without DSS. Associations of LBP and radicular pain reported within one month (30 days) and one year (365 days) of the MRI, with clinical and radiological information, were also investigated by utilizing univariate and multivariate logistic regressions.

RESULTS

Subjects with DSS had higher prevalence of radicular leg pain, more pain-related disability, and lower quality of life (all p < 0.05). Subjects with DSS had 1.5 (95% confidence interval (CI) 1.0 to 2.1; p = 0.027) and 1.8 (95% CI 1.3 to 2.6; p = 0.001) times higher odds of having radicular leg pain in the past month and the past year, respectively. However, DSS was not associated with LBP. Although, subjects with a spondylolisthesis had 1.7 (95% CI 1.1 to 2.5; p = 0.011) and 2.0 (95% CI 1.2 to 3.2; p = 0.008) times greater odds to experience LBP in the past month and the past year, respectively.

CONCLUSION

This large-scale study identified DSS as a risk factor of acute and chronic radicular leg pain. DSS was seen in 6.9% of the study cohort and these patients had narrower spinal canals. Subjects with DSS had earlier onset of symptoms, more severe radicular leg pain, which lasted for longer and were more likely to have worse disability and poorer quality of life. In these patients there is an increased likelihood of nerve root compression due to a pre-existing narrowed canal, which is important when planning surgery as patients are likely to require multi-level decompression surgery. Cite this article: Bone Joint J 2021;103-B(1):131-140.

Comparison of the Pull-Out Strength between a Novel Micro-Dynamic Pedicle Screw and a Traditional Pedicle Screw in Lumbar Spine

OBJECTIVE

This study aimed to investigate the strength of a novel micro-dynamic pedicle screw by comparing it to the traditional pedicle screw.

METHODS

Forty-five lumbar vertebrae received a traditional pedicle screw on one side and a micro-dynamic pedicle screw on the other side as follows (traditional group vs micro-dynamic group): 15 vertebrae underwent instant pull-out testing; 15 vertebrae underwent 5000-cyclic fatigue loading testing; and 15 vertebrae underwent 10,000-cyclic fatigue loading testing and micro-computed tomography (micro-CT) scanning. The peek pull-out force and normalized peek pull-out force after instant pull-out testing, 5000-cyclic and 10,000-cyclic fatigue loading testing were recorded to estimate the resistance of two types of screws. Bone mineral density was recorded to investigate the strength of the different screws in osteoporotic patients. And the semidiameter of the screw insertion area on micro-CT images after fatigue were compared to describe the performance between screw and bone surface.

RESULTS

The bone mineral density showed a weak correlation with peek pull-out force (r = 0.252, P = 0.024). The peek pull-out force of traditional pedicle screw after 10,000-cyclic fatigue loading were smaller than that of instant pull-out test in both osteoporotic (P = 0.017) and healthy group (P = 0.029), the peek pull-out force of micro-dynamic pedicle screw after 10,000-cyclic fatigue loading was smaller than that in instant pull-out test in osteoporotic group (P = 0.033), but no significant difference in healthy group (P = 0.853). The peek pull-out force in traditional group and micro-dynamic group underwent instant pull-out testing (P = 0.485), and pull-out testing after 5000-cyclic fatigue loading testing (P = 0.184) did not show significant difference. However, the peek pull-out force in micro-dynamic group underwent pull-test after 10,000-cyclic fatigue loading testing was significantly greater than that measured in traditional group (P = 0.005). The normalized peek pull-out force of traditional groups underwent instant pull-out testing, pull-out test after 5000-cyclic and 10,000-cyclic fatigue loading testing significantly decreased as the number of cycles increased (P < 0.001); meanwhile, the normalized peek pull-out force of micro-dynamic groups remained consistent regardless of the number of cycles (P = 0.133). The semidiameter after the fatigue loading test of the traditional screw insertion area was significantly larger than that of the micro-dynamic screw insertion area (P = 0.013).

CONCLUSION

The novel micro-dynamic pedicle screw provides stronger fixation stability in high-cyclic fatigue loading and non-osteoporotic patients versus the traditional pedicle screw, but similar resistance in low-cycle fatigue testing and osteoporotic group vs the traditional pedicle screw.

Predicting spondylolisthesis correction with prone traction radiographs

Aims

To determine the effectiveness of prone traction radiographs in predicting postoperative slip distance, slip angle, changes in disc height, and lordosis after surgery for degenerative spondylolisthesis of the lumbar spine.

Methods

A total of 63 consecutive patients with a degenerative spondylolisthesis and preoperative prone traction radiographs obtained since 2010 were studied. Slip distance, slip angle, disc height, segmental lordosis, and global lordosis (L1 to S1) were measured on preoperative lateral standing radiographs, flexion-extension lateral radiographs, prone traction lateral radiographs, and postoperative lateral standing radiographs. Patients were divided into two groups: posterolateral fusion or posterolateral fusion with interbody fusion.

Results

The mean changes in segmental lordosis and global lordosis were 7.1° (SD 6.7°) and 2.9° (SD 9.9°) respectively for the interbody fusion group, and 0.8° (SD 5.1°) and -0.4° (SD 10.1°) respectively for the posterolateral fusion-only group. Segmental lordosis (ρ = 0.794, p < 0.001) corrected by interbody fusion correlated best with prone traction radiographs. Global lumbar lordosis (ρ = 0.788, p < 0.001) correlated best with the interbody fusion group and preoperative lateral standing radiographs. The least difference in slip distance (-0.3 mm (SD 1.7 mm), p < 0.001), slip angle (0.9° (SD 5.2°), p < 0.001), and disc height (0.02 mm (SD 2.4 mm), p < 0.001) was seen between prone traction and postoperative radiographs. Regression analyses suggested that prone traction parameters best predicted correction of slip distance (Corrected Akaike’s Information Criterion (AICc) = 37.336) and disc height (AICc = 58.096), while correction of slip angle (AICc = 26.453) was best predicted by extension radiographs. Receiver operating characteristic (ROC) cut-off showed, with 68.3% sensitivity and 64.5% specificity, that to achieve a 3.0° increase in segmental lordotic angle, patients with a prone traction disc height of 8.5 mm needed an interbody fusion.

Conclusion

Prone traction radiographs best predict the slip distance and disc height correction achieved by interbody fusion for lumbar degenerative spondylolisthesis. To achieve this maximum correction, interbody fusion should be undertaken if a disc height of more than 8.5 mm is attained on preoperative prone traction radiographs. Level of Evidence: Level II Prognostic Study Cite this article: Bone Joint J 2020;102-B(8):1062–1071.

Intradural Lumbar Disc Herniation: A Case Report and Literature Review

Background

Lumbar disc herniation into the dural space is a very rare phenomenon of degenerative lumbar lesions in the elderly population, and its potential pathogenesis and natural course remain unclear.

Case description

We describe a rare case of intradural lumbar disc herniation. A 68-year-old man presented with progressive lower back pain and radiating pain and numbness in both legs for 3 years. Magnetic resonance imaging revealed a large herniated disc at L4-L5. Posterior discectomy and fusion of the L4-L5 was performed after conservative treatment failed. Intraoperatively, only minimal disc fragments in the epidural space were found after meticulous probing following laminectomy of the L4-L5 vertebrae. The dorsal dura mater was saturated, tense, and bulged at the L4-L5 levels; additionally, an intradural mass was palpable and confirmed by intraoperative ultrasonography. Subsequently, dorsal middle durotomy was performed. Upon opening the dural sac, a large cauliflower-like mass similar to nucleus pulposus tissue was found near the arachnoid membrane. The mass was dissociative and could be completely resected. The dorsal dural incisions were closed after careful exploration, followed by fixation and fusion of the L4-L5 levels. Pathological examination revealed disc tissue with central balloon-type cystic degenerative changes. The patient’s lower back pain and radiating pain and numbness of both legs improved remarkably postoperatively, and he became asymptomatic at 3 months postoperatively.

Conclusion

Intradural lumbar disc herniation should be highly suspected when intraoperative findings are incompatible with findings from the preoperative imaging examination, and it could be further confirmed via intraoperative ultrasonography and pathological examination of the resected tissue from the dural space. Prompt surgery is recommended, and surgical results are usually favorable. We also reviewed the literature and discussed the potential pathogenesis, natural course, diagnosis, and treatment of intradural lumbar disc herniation.