Minimally invasive lateral interbody fusion for the treatment of rostral adjacent-segment lumbar degenerative stenosis without supplemental pedicle screw fixation

Analysis of factors affecting the clinical management of infection in culture-negative patients following percutaneous endoscopic decompression: a retrospective study

Background

Culture-negative spinal infections after prophylactic antibiotic use in percutaneous endoscopic decompression are rare, and diagnostic difficulties and the risk of antibiotic-resistant infections complicate treatment. This study retrospectively analyzed the medical records of culture-negative patients following percutaneous endoscopic surgery to identify risk factors influencing antimicrobial therapy and provide insights for clinical management.

Methods

Data were retrospectively collected from patients who underwent lumbar percutaneous endoscopic decompression at the Affiliated Hospital of Qingdao University between January 2014 and June 2023. The patients' medical records were reviewed. Patient demographics, hidden blood loss, daily blood glucose control, and maximum temperature during treatment were recorded as potential risk factors. C-reactive protein, procalcitonin, white blood cells, erythrocyte sedimentation rate, and the duration of antibiotic treatment were used as indicators of infection treatment. The impact of these risk factors on infection was then analyzed.

Results

The results showed that blood glucose control was strongly correlated with the severity of infection (Beta = 0.60, P = 0.00), strongly correlated with short-term treatment effectiveness (Beta = 0.65, P = 0.00), and moderately correlated with the duration of antibiotic treatment (Beta = 0.41, P = 0.01). Hidden blood loss was moderately correlated with the severity of infection (Partial-R = 0.49, P = 0.00) and moderately correlated with the duration of antibiotic treatment (Partial-R = 0.48, P = 0.00). Hidden blood loss index was moderately correlated with the duration of antibiotic treatment (Partial-R = 0.50, P = 0.00). Female was a favorable factor to shorten the duration of antibiotic treatment (Beta = -0.25, P = 0.01), and higher maximum temperature during infection may indicate a longer duration of antibiotic treatment (Beta = 0.28, P = 0.02).

Conclusion

Our findings suggest that healthy blood glucose levels, a lower hidden blood loss and hidden blood loss index might help reduce the duration of antibiotic use after infection. Effective hemostasis during surgery to reduce hidden blood loss and good preoperative blood glucose control indicators are both beneficial measures for infection treatment.

Comparative study of percutaneous endoscopic lumbar decompression and traditional revision surgery in the treatment of symptomatic adjacent segment degeneration

OBJECTIVE

The objective of this study is to evaluate and compare the surgical outcomes and complications of Percutaneous Endoscopic Lumbar Decompression (PELD) and traditional revision surgery in treating symptomatic Adjacent Segment Degeneration (ASD). This comparison aims to delineate the advantages and disadvantages of these methods, assisting spine surgeons in making informed surgical decisions.

METHODS

66 patients with symptomatic ASD who failed conservative treatment for more than 1 month and received repeated lumbar surgery were retrospectively collected in the study from January 2015 to November 2018, with the average age of 65.86 ± 11.04 years old. According to the type of surgery they received, all the patients were divided in 2 groups, including 32 patients replaced the prior rod in Group A and 34 patients received PELD at the adjacent level in Group B. Patients were followed up routinely and received clinical and radiological evaluation at 3, 6, 12 months and yearly postoperatively. Complications and hospital costs were recorded through chart reviews.

RESULTS

The majority of patients experienced positive surgical outcomes. However, three cases encountered complications. Notably, Group B patients demonstrated superior pain relief and improved postoperative functional scores throughout the follow-up period, alongside reduced hospital costs (P < 0.05). Additionally, significant reductions in average operative time, blood loss, and hospital stay were observed in Group B (P < 0.05). Notwithstanding these benefits, three patients in Group B experienced disc re-herniation and underwent subsequent revision surgeries.

CONCLUSIONS

While PELD offers several advantages over traditional revision surgery, such as reduced operative time, blood loss, and hospital stay, it also presents a higher likelihood of requiring subsequent revision surgeries. Future studies involving a larger cohort and extended follow-up periods are essential to fully assess the relative benefits and drawbacks of these surgical approaches for ASD.

Preoperative Multifidus Muscle Quality is Associated With Patient Reported Outcomes After Lateral Lumbar Interbody Fusion

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

Lateral lumbar interbody fusion (LLIF) commonly involves a transpsoas approach. Despite the association between LLIF, postoperative iliopsoas weakness, and iatrogenic neuropraxia, no study has yet examined the effect of psoas or multifidus muscle quality on patient-reported outcomes (PROs).

METHODS

This study retrospectively reviewed patients who underwent LLIF with 1-year minimum follow-up. Psoas and multifidus muscle qualities were graded on preoperative magnetic resonance imaging using two validated classification systems for muscle atrophy. Average muscle quality was calculated as the mean score from all levels (L1-2 through L5-S1). Univariate and multivariate statistics were utilized to investigate the relationship between psoas/multifidus muscle quality and preoperative, 6-weeks postoperative, and final postoperative PROs.

RESULTS

74 patients (110 levels) with a mean follow-up of 18.71 ± 8.02 months were included for analysis. Greater multifidus atrophy was associated with less improvement on ODI, SF12, and VR12 (P < .05) on univariate analysis. On multivariate analysis, worse multifidus atrophy predicted less improvement on SF12 and VR12 (P < .05).

CONCLUSION

Despite the direct manipulation of the psoas muscle inherent to LLIF, preoperative psoas muscle quality did not affect postoperative outcomes. Rather, the extent of preoperative multifidus fatty infiltration and atrophy was more likely to predict postoperative pain and disability. These findings suggest that multifidus atrophy may be more pertinent than psoas atrophy in its association with patient-reported outcome measures after LLIF.

Biomechanical Comparison of Different Surgical Approaches for the Treatment of Adjacent Segment Diseases after Primary Transforaminal Lumbar Interbody Fusion: A Finite Element Analysis

BACKGROUND AND OBJECTIVE

Adjacent segment disease (ASD) is a well-known complication after interbody fusion. Revision surgery is necessary for symptomatic ASD to further decompress and fix the affected segment. However, no optimal construct is accepted as a standard in treating ASD. The purpose of this study was to compare the biomechanical effects of different surgical approaches for the treatment of ASD after primary transforaminal lumbar interbody fusion (TLIF).

METHODS

A finite element model of the L1-S1 was conducted based on computed tomography scan images. The primary surgery model was developed with a single-level TLIF at L4-L5 segment. The revision surgical models were developed with anterior lumbar interbody fusion (ALIF), lateral lumbar interbody fusion (LLIF), or TLIF at L3-L4 segment. The range of motion (ROM), intradiscal pressure (IDP), and the stress in cages were compared to investigate the biomechanical influences of different surgical approaches.

RESULTS

The results indicated that all the three surgical approaches can stabilize the spinal segment by reducing the ROM at revision level. The ROM and IDP at adjacent segments of revision model of TLIF was greater than those of other revision models. While revision surgery with ALIF and LLIF had similar effects on the ROM and IDP of adjacent segments. Compared among all the surgical models, cage stress in revision model of TLIF was the maximum in extension and axial rotation.

CONCLUSION

The IDP at adjacent segments and stress in cages of revision model of TLIF was greater than those of ALIF and LLIF. This may be that direct extension of the surgical segment in the same direction results in stress concentration.

Adjacent segment degeneration after posterolateral lumbar fusion: results and complications of posterior revision surgery

BACKGROUND

Lumbar fusion is an important technique for the treatment of degenerative pathologies. Adjacent segment degeneration is a known complication after lumbar fusion that causes significant morbidity. Our objective was to evaluate the demographics, risk factors, type of surgery, and surgical complications in patients who underwent reoperation through a posterior route due to adjacent segment degeneration.

METHODS

We performed a retrospective analysis of all patients who underwent instrumented posterolateral fusion in the lumbar spine for the treatment of degenerative diseases from January 2000 to December 2015 at a single institution. Patients who developed symptomatic adjacent segment degeneration requiring a second surgery were noted and compared with patients who did not develop adjacent segment degeneration.

RESULTS

A total of 750 patients with degenerative pathologies who underwent fusion with instrumentation were identified. Forty-five patients (6%) required a second surgery for symptomatic adjacent segment degeneration. The average onset of adjacent segment degeneration symptoms after fusion was 5.89 years. Adjacent segment degeneration occurred above the level of fusion in 40 cases and below in 5 cases. The risk factor identified in our series was L5-S1 fusion. The main complication seen after the second surgery was infection in 5 cases (11%).

CONCLUSIONS

This study identifies the L5-S1 fusion as a possible risk factor for adjacent segment degeneration. Reoperation through a posterior route is a therapeutic option but is associated with considerable morbidity. Further studies are necessary to elucidate this pathology and the best options for its management.

Stand-Alone Oblique Lumbar Interbody Fusion (OLIF) for the Treatment of Adjacent Segment Disease (ASD) after Previous Posterior Lumbar Fusion: Clinical and Radiological Outcomes and Comparison with Posterior Revision Surgery

Background: Radiological evidence of adjacent segment disease (ASD) has been reported to have a prevalence of more than 30% and several risk factors have been reported. The aim of this study is to evaluate the clinical and radiological outcomes of patients with symptomatic ASD treated with stand-alone OLIF and compare results with a posterior revision surgery cohort. Methods: This is a retrospective case-control study. Clinical-patient-reported outcomes were obtained at preoperative, postoperative and final follow-up visits using the Short Form (SF-36) scale, the Oswestry Disability Index (ODI) and the visual analog scale (VAS). Radiological measures include lumbar lordosis (LL), segmental lordosis (SL), pelvic incidence-lumbar lordosis (PI-LL) mismatch, segmental coronal Cobb angle and intervertebral disc height (DH). The data are compared with a retrospective series of patients that underwent a posterior revision surgery for ASD. Results: Twenty-eight patients in the OLIF group and 25 patients in the posterior group meet inclusion criteria. The mean ages at the time of the surgery are 65.1 years and 67.5, respectively. The mean follow-up time is 36.1 months (range of 14-56). The clinical outcomes significantly improve from preoperative values from the surgery in both groups. The radiological parameters are significantly improved postoperatively and were maintained at the last follow-up in both groups. A statistically significant difference is observed between the two groups for minor complication rate, length of surgery, blood loss and DH restoration. Conclusions: Stand-alone OLIF is an effective and safe technique with low morbidity and complication rates for the treatment of selected patients with symptomatic ASD following a previous lumbar fusion.

Comparison of Oblique Lumbar Interbody Fusion Combined with Posterior Decompression (OLIF-PD) and Posterior Lumbar Interbody Fusion (PLIF) in the Treatment of Adjacent Segmental Disease(ASD)

BACKGROUND

An unintended consequence following lumbar fusion is the development of adjacent segment disease (ASD). Oblique lumbar interbody fusion combined with posterior decompression (OLIF-PD) is another feasible option for ASD, and there is no literature report on this combined surgical strategy.

METHODS

A retrospective analysis was performed on 18 ASD patients requiring direct decompression in our hospital between September 2017 and January 2022. Among them, eight patients underwent OLIF-PD revision and ten underwent PLIF revision. There were no significant differences in the baseline data between the two groups. The clinical outcomes and complications were compared between the two groups.

RESULTS

The operation time, operative blood loss and postoperative hospital stay in the OLIF-PD group were significantly lower than those in the PLIF group. The VAS of low back pain in the OLIF-PD group was significantly better than that in the PLIF group during the postoperative follow-up. The ODI at the last follow-up in the OLIF-PD group and the PLIF group were significantly relieved compared with those before operation. The excellent and good rate of the modified MacNab standard at the last follow-up was 87.5% in the OLIF-PD group and 70% in the PLIF group. There was a statistically significant difference in the incidence of complications between the two groups.

CONCLUSION

For ASD requiring direct decompression after posterior lumbar fusion, compared with traditional PLIF revision surgery, OLIF-PD has a similar clinical effect, but has a reduced operation time, blood loss, hospital stay and complications. OLIF-PD may be an alternative revision strategy for ASD.

MIS-TLIF or CLIF for single segmental lumbar degenerative disease

We aimed to compare the effect of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and Crenel lateral interbody fusion (CLIF) on single segmental lumbar degenerative disease. Patients with single segmental lumbar degenerative disease undergoing MIS-TLIF (n = 28) and CLIF (n = 28) were enrolled from April to October 2017. Preoperative medical history, anthropometric data, and clinical data were recorded. Visual analogue scores and Oswestry disability index (ODI) were assessed. Radiography was performed before and after surgery. X-ray films were evaluated according to the Bridwell method, visual analogue scores and ODI scores were evaluated. There were no significant differences in the gender, age, clinical diagnosis, involved segment or preoperative ODI score between 2 groups (P > .05). During 12-month follow-up, MIS-TLIF group had less intraoperative blood loss, drainage, postoperative bedridden time, and hospital stay (P < .05), but more operation time and radiation exposure time compared with CLIF group (P < .05). CLIF group reported less pain than MIS-TLIF group (P > .05). Both groups had similar lumbar fusion rate (P > .05). Overall, CLIF has less complications, less trauma and faster recovery for the treatment of single segmental lumbar degenerate disease when compared with MIS-TLIF. Evaluation of more patients and long-term follow-up are still needed to further validate our findings.

Indirect decompression via oblique lumbar interbody fusion is sufficient for treatment of lumbar foraminal stenosis

Oblique lumbar interbody fusion (OLIF) is a popular technique for the treatment of degenerative lumbar spinal disease. There are no clear guidelines on whether direct posterior decompression (PD) is necessary after OLIF. The purpose of this study was to analyze the effect of the indirect decompression obtained from OLIF in patients with lumbar foraminal stenosis. We retrospectively reviewed 33 patients who underwent OLIF surgery for degenerative lumbar spinal disease between 1 January 2018, and 30 June 2019. The inclusion criteria included patients who were diagnosed with lumbar foraminal stenosis by preoperative MRI. The exclusion criteria included the presence of central canal stenosis, spinal infection, vertebral fractures, and spinal malignancies. The clinical results, evaluated using the visual analogue scale of back pain (VAS-Back), VAS of leg pain (VAS-Leg), and Oswestry disability index (ODI), were recorded. The radiologic parameters were also measured. The VAS-Back, VAS-Leg, and ODI showed significant improvement in both the PD and non-posterior decompression (Non-PD) groups postoperatively (all, p < 0.05). Patients in the Non-PD group showed better results than those in the PD group in the VAS-Back at 12- and 24 months postoperatively (0.00 vs. 3.00 postoperatively at 12 months, p = 0.030; 0.00 vs. 4.00 postoperatively at 24 months, p = 0.009). In addition, the ODI at 24 months postoperatively showed better improvement in the Non-PD group (8.89 vs. 24.44, p = 0.038). The disc height in both the PD and the Non-PD groups increased significantly postoperatively (all, p < 0.05), but the restoration of foraminal height was significantly different only in the Non-PD group. There was no statistically significant difference in cage position, cage subsidence, fusion grade, or screw loosening between the PD and the Non-PD groups. Indirect decompression via OLIF for lumbar foraminal stenosis showed favorable outcomes. The use of interbody cages and posterior instrumentation was sufficient for relieving symptoms in patients with lumbar foraminal stenosis. Additional direct posterior decompression may deteriorate results in the follow-up period.

Incidence of major and minor vascular injuries during lateral access lumbar interbody fusion procedures: a retrospective comparative study and systematic literature review

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications. We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms "vascular injury" and "lateral lumbar surgery." Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0-15.4% and minor vascular injury occurred in 0-6% of lateral lumbar fusions. The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

Oblique Lumbar Interbody Fusion Using a Stand-Alone Construct for the Treatment of Adjacent-Segment Lumbar Degenerative Disease

Objective

Adjacent-segment disease (ASD) is common in patients undergone previous lumbar fusion. A typical revision treatment from posterior approach requires management of postoperative scar tissue and previously implanted instrumentation. An oblique lumbar interbody fusion (OLIF) approach allows surgeon to reduce the potential risk of posterior approach. This study aimed to analyze the clinical and radiographic efficacy of stand-alone OLIF for the treatment of lumbar adjacent-segment disease.

Methods

A total of 13 consecutive patients who underwent stand-alone OLIF for the treatment of adjacent-segment disease from December 2016 to January 2019 were reviewed. Visual analog scale (VAS) of back pain and leg pain and the Oswestry Disability Index (ODI) before surgery and at last postoperative clinic visits were obtained. Radiography, CT and MRI before and at last follow-up after surgery was evaluated in all patients.

Results

During the study period, 13 cases were successfully treated with stand-alone OLIF. The mean follow-up was 17.7 ± 8.3 months. The back pain VAS improved from 6.2 ± 1.0 to 2.0 ± 1.1 (P < 0.01), and the leg pain VAS improved from 7.0 ± 1.9 to 1.0 ± 0.9 (P < 0.01). ODI improved from 28.0 ± 7.5 to 10.8 ± 4.0 (P < 0.01). The disc height (DH) increased from 9 ± 2 to 12 ± 2 mm (P < 0.01), the cross-sectional area (CSA) of spinal canal increased from 85 ± 26 to 132 ± 24 mm² (P < 0.01), the foraminal height increased from 17 ± 2 to 21 ± 3 mm (P < 0.01) and the CSA of foramen increased from 95 ± 25 to 155 ± 36 mm² (P < 0.01). Cage subsidence was observed in 2 cases.

Conclusions

Stand-alone OLIF provides a safe and effective alternative way to treat ASD.

Early Outcomes of 3D-printed Porous Titanium versus Polyetheretherketone (PEEK) Cage Implantation for Standalone Lateral Lumbar Interbody Fusion in the Treatment of Symptomatic Adjacent Segment Degeneration

OBJECTIVE

This study compared outcomes of 3D-printed porous titanium (Ti) versus polyetheretherketone (PEEK) cage implantation for standalone lateral lumbar interbody fusion (SA-LLIF) in the treatment of symptomatic adjacent segment degeneration (ASD).

METHODS

44 patients (59 levels) underwent SA-LLIF with Ti or PEEK cages between 10/2016 and 07/2020. The primary outcome was cage subsidence according to Marchi et al. Secondary outcomes included revision/recommendations for revision surgery, back/leg pain severity, changes in disc/foraminal height and global/segmental lumbar lordosis.

RESULTS

44 patients (21 female) were included with a mean age at surgery of 61.8±11.5 years, average radiological follow-up of 12.5±8.2 and clinical follow-up of 11.0±7.1 months. The overall subsidence rate was significantly less in the Ti versus PEEK group (20% vs. 58.8%; p=0.004). Revision was recommended to none of the patients in the Ti and 3 in the PEEK group (p=0.239). Furthermore, patients in the Ti group showed significantly better improvement in back pain NRS score (p=0.001). Disc height (p<0.001) and foraminal height restoration (p=0.011) were statistically significant in the Ti group, whereas only disc height restoration was significant in the PEEK group (p=0.003).

CONCLUSION

In patients undergoing SA-LLIF for ASD treatment, 3D-printed Ti cages had significantly lower overall subsidence rate compared to PEEK cages. Furthermore, Ti cages resulted in fewer recommendations for revision surgery. Whether greater pain reduction in the Ti group is associated with earlier or higher fusion rates needs to be further elucidated.

Preoperative Pelvic Incidence Minus Lumbar Lordosis Mismatch in Repeat Posterior Lumbar Interbody Fusion Induces Subsequent Corrective Long Fusion

OBJECTIVE

Only a few studies have addressed clinical outcomes of revision surgery for adjacent segment disease. The purpose of this study was to elucidate clinical outcomes of second (repeat) posterior lumbar interbody fusion (PLIF) by focusing on the relationship between clinical outcomes and spinopelvic parameters and predisposing factors requiring subsequent corrective long fusion after repeat PLIF.

METHODS

We analyzed the data of 47 patients ≥40 years old who underwent repeat PLIF after single-segment PLIF owing to adjacent segment disease. The correlation between clinical outcomes and radiographic parameters was investigated. Patient demographics and radiographic parameters were compared between patients with and without subsequent corrective long fusion.

RESULTS

Japanese Orthopaedic Association score at final follow-up was 13.4, and the recovery rate was 37.2%. All sagittal parameters except pelvic tilt and C7-central sacral vertical line at final follow-up showed weak to moderate (|r| = 0.30-0.56) correlation with clinical scores. Finally, 11% of patients required subsequent long corrective fusion. Pelvic incidence minus lumbar lordosis (PI-LL) mismatch (cutoff value of 27.5°) and thoracic kyphosis (cutoff value of 12.5°) before repeat PLIF were identified as predisposing factors for subsequent long corrective fusion.

CONCLUSIONS

The clinical outcomes of repeat PLIF were inferior to outcomes of primary PLIF. Once PI-LL mismatch occurs after initial PLIF, it will be difficult to resolve the PI-LL mismatch during the second PLIF. To stop the chain of reoperations in patients whose preoperative PI-LL exceeds 27.5° before repeat PLIF, corrective long fusion may be a surgical option to consider.

Comparison of the differentiation abilities of bone marrow-derived mesenchymal stem cells and adipose-derived mesenchymal stem cells toward nucleus pulposus-like cells in three-dimensional culture

Nucleus pulposus cell (NPC) transplantation can be a potential therapeutic approach for intervertebral disc degeneration (IDD). However, low cell viability has restricted the therapeutic capacity of NPCs, and sources of natural NPCs are limited. Bone marrow-derived mesenchymal stem cells (BMSCs) and adipose-derived mesenchymal stem cells (ADSCs) can be differentiated toward NPC-like cells. However, it is unknown whether there are differences in the abilities of these two cell types to differentiate into NPC-like cells, or which cell type exhibits the best differentiation ability. The present study compared the abilities of BMSCs and ADSCs to differentiate toward NPC-like cells with or without a 3D culture system to lay a foundation for stem cell transplantation therapy for IDD. BMSCs were isolated from the rat whole bone marrow cell using the repeated adherent culture method. ADSCs were isolated from rat adipose tissues in the subcutaneous inguinal region using the enzyme digestion method. Cells were identified using flow cytometry. Cell viability was assessed via Cell Counting Kit-8 assays, and reverse transcription-quantitative PCR and western blotting were carried out to evaluate the expression of NPC markers and chondrocyte-specific genes. Glycosaminoglycans (GAGs) and proteoglycans were examined via Alcian blue and safranin O staining, respectively. ADSCs in 3D culture displayed the highest cell proliferative ability, compared with the 2D culture system and BMSC culture. In addition, ADSCs in 3D culture exhibited increased GAG and proteoglycan synthesis than BMSCs. Compared with BMSCs in 3D culture, ADSCs in 3D culture exhibited higher mRNA and protein expression of NPC marker genes (hypoxia-inducible factor 1-α, glucose transporter 1) and chondrocyte-specific genes (Sox-9, aggrecan and type II collagen). The present findings indicated that ADSCs exhibited a better ability to differentiate into NPC-like cells in 3D culture compared with BMSCs, which may be of value for the regeneration of intervertebral discs using cell transplantation therapy.

Segmental Arteries and Veins at Higher Lumbar Levels Can Intersect the Adjacent Caudal Intervertebral Disc in the Anterior Part of the Spinal Column: A Cadaveric Analysis

Study Design

A cadaveric study.

Purpose

To investigate the anatomical features of segmental arteries and veins in the anterior part of the spinal column to prevent segmental vessel injury.

Overview of Literature

The lateral transpsoas approach to the lumbar intervertebral discs (IVD) is associated with the risk of segmental vessel injury. Previous studies have described the vascular anatomy on the lateral part of the vertebral body. However, there are no studies that describe the segmental vessels on its anterior aspect. Here, we report the important anatomical features of the segmental arteries and veins that can intersect the anterior part of the IVD. These vessels are considered at risk of vascular injury when placing the anterior retractors during lateral lumbar interbody fusion or cutting the anterior longitudinal ligament during anterior column realignment.

Methods

Five formalin-embalmed human cadavers were used. We assessed the proportion of segmental arteries and veins that intersected the IVD in the L2–L5 range and their course on the anterior part of the spinal column.

Results

The segmental arteries and veins commonly intersect the anterior part of the IVD (artery, 28.1%; vein, 42.1%). Seven of 10 (70%) segmental arteries at L2 intersected the IVD, but only one artery intersected the IVD at L3 and L4. The proportions of segmental veins that intersected the IVD were 60%, 50%, and 16.7% at L2, L3, and L4, respectively.

Conclusions

The segmental arteries and veins frequently intersect the IVD in the anterior part of the spinal column. Therefore, it is necessary to consider these individual anatomical features to prevent vascular damage during lateral lumbar interbody fusion surgery.

Implant Preservation versus Implant Replacement in Revision Surgery for Adjacent Segment Disease After Thoracolumbar Instrumentation: A Retrospective Study of 43 Patients

OBJECTIVE

To evaluate the mechanical properties of a new connector rod aiming to preserve implants in revision surgery (RS) for adjacent segment disease, a problematic complication of instrumented spinal fusion, and to assess its clinical applicability.

METHODS

The mechanical properties of the connector-rod construct (implant preservation) and traditional rod construct (implant replacement) were evaluated and compared. Forty-three patients underwent RS for adjacent segment disease in the thoracolumbar spine with implant preservation or replacement, and radiological and clinical outcomes were assessed.

RESULTS

Mechanical properties in group A were comparable to those in group B. Total mean time from prior surgery to RS was 6.86 ± 1.08 years. Surgical time and blood loss values of group A were 40.14% and 29.29% statistically significantly smaller than values of group B. In group B, 12% (3/25) of patients developed surgical site infections. In both groups, the visual analog scale leg score decreased significantly after RS. Early postoperative (at 1-month and 3-month follow-up) Oswestry Disability Index and visual analog scale back scores of group A were significantly lower than those of group B; the difference in the visual analog scale back score between groups was significant until the 6-month follow-up. No implant failures occurred, and spinal fusion was achieved in all cases.

CONCLUSIONS

The connector rod is considered safe and can reduce the surgical time, blood loss, risk of complications, and medical costs. Better early postoperative clinical outcomes can be achieved with the rod owing to less surgical trauma.

The Safety and Efficacy of Stand-Alone Lateral Lumbar Interbody Fusion for Adjacent Segment Disease in a Cohort of 44 Patients

BACKGROUND

A mainstay of treatment for symptomatic adjacent segment disease (ASD) has consisted of revision with posterior decompression and fusion. This carries significant morbidity and can be technically difficult. An alternative is stand-alone lateral lumbar interbody fusion (LLIF), which may avoid complications associated with revision surgery. We describe the largest cohort of patients treated with LLIF for ASD to our knowledge.

METHODS

We conducted a retrospective cohort study on all patients who underwent transpsoas LLIF for ASD at a single academic center between 2012 and 2019. Postoperative improvement was measured using the Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI).

RESULTS

Forty-four patients who underwent LLIF for ASD were identified. Median age was 65 years. Median time from index surgery to ASD development was 78 months. Median levels fused via LLIF was 1. Our median follow-up was 358 days. At follow-up, the median VAS back pain score was 0 (mean, 0.884), median VAS leg pain score was 1 (mean, 0.953), and median ODI was 8. The median improvement for VAS back pain was 8, for VAS leg pain was 6, and for ODI was 40. No patients suffered new neurologic symptoms postoperatively. Of the 17 patients who initially presented with non-pain neurologic symptoms, 8 (47.1%) experienced complete resolution of symptoms, and 5 (29.4%) experienced only some improvement.

CONCLUSIONS

To our knowledge, this is the largest cohort study of patients to date evaluating stand-alone LLIF for ASD. Our patient outcomes show it is safe and effective with low risk of morbidity.

Clinical and Radiographic Outcomes of Lateral Interbody Fusion for Adjacent Segment Degeneration

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Assessment of outcomes in patients undergoing lateral interbody fusion as part of the surgical treatment of adjacent segment deterioration after previous lumbar spine fusion.

METHODS

Adult patients with previous lumbar posterior spinal fusion who presented with adjacent segment degeneration and stenosis refractory to nonoperative treatment and who underwent lateral lumbar interbody fusion were retrospectively analyzed. Clinical and radiographic outcomes were assessed and comparisons made between preoperative baseline and postoperative values.

RESULTS

Thirty-six patients with symptomatic adjacent segment degeneration at 46 motion segments were included. Thirty (83.3%) of the 36 patients had complete relief of both preoperative lower extremity pain and back pain at the time of final follow-up. Six (16.7%) of the 36 patients had persistent pain, though in all 6 cases, the pain was less postoperatively than preoperatively. Oswestry Disability Index scores were improved significantly at final follow-up (P = .001). Compared with preoperative baseline parameters, initial and final postoperative radiographs had an increase in segmental lordosis (P < .001 and P < .001, respectively), increase in overall lumbar lordosis (P < .05 and P = .094, respectively), decrease in segmental coronal angulation (P = .63 and P < .01, respectively), decrease in overall coronal angulation (P = .063 and P = .009, respectively), and increase in intervertebral height (P < .001 and P < .001, respectively).

CONCLUSION

Lateral lumbar interbody fusion achieves favorable clinical and radiographic outcomes for the treatment of adjacent segment degeneration after previous lumbar fusion.

LEVEL OF EVIDENCE

4.

Interspinous Process Fixation Device Versus Extended Pedicle Screw Fixation for Symptomatic Adjacent Segment Disease: 3-Year Retrospective Study

OBJECTIVE

In the present study, we compared the clinical and radiographic outcomes of an interspinous process fixation device (IFD) with those of extended pedicle screw fixation (PSF) for symptomatic adjacent segment disease (ASD) after lumbar fusion.

METHODS

The data from 109 patients with ASD treated with IFD (n = 48) or extended PSF (n = 61) from January 2009 to January 2016 were reviewed retrospectively. The clinical outcomes were measured using a visual analog scale (VAS) and the Oswestry disability index. The radiographic outcomes included the fusion rate, incidence of cage subsidence, and additional radiographic ASD.

RESULTS

The mean incision length, operative time, blood loss, and length of hospital stay were significantly lower in the IFD group (P < 0.001). Postoperative back and leg pain were relieved in both groups (P < 0.001). The mean preoperative VAS scores were 8.3 ± 1.3 and 8.5 ± 1.1 in the IFD and PSF groups and had improved to 2.8 ± 1.1 and 2.7 ± 1.2 after 36 months, respectively (P < 0.001). At 36 months postoperatively, 10 of the 56 patients (17.9%) in the PSF group had developed additional radiographic ASD compared with 2 of 44 patients (4.5%) in the IFD group.

CONCLUSION

Our results have demonstrated that in the treatment of symptomatic ASD, comparable clinical and radiologic outcomes can be achieved using IFD, which has a shorter skin incision, shorter operative time, less intraoperative blood loss, and shorter hospital stay than the extended PSF technique. Although not statistically significant, the IFD resulted in a lower ASD incidence compare with the PSF technique. Thus, IFD might be an alternative surgical method for symptomatic ASD after lumbar spine fusion.

Early Discharged Lumbar Spine Fusion Reduced Postoperative Readmissions: A Retrospective Cohort Study

Early discharge (ED) has emerged and gained popularity in spine surgery. However, the benefits of ED in lumbar fusion have not yet been validated by large cohort studies. To evaluate the effects of ED on readmissions and reoperations in lumbar fusion, this study utilized a national database to enroll patients who had undergone lumbar fusion surgery at age 50–70 years, and grouped them into an ED group or a comparison group. In the comprehensive follow-up of 180 days post-operation, the two groups were compared. There were 18,008 patients in the cohort, including 2172 in the ED group and 15,836 in the comparison group. The ED group was slightly younger (59.9 vs. 60.7 years, p < 0.001), more male predominant (44.9% vs. 36.9%, p < 0.001), and had fewer medical comorbidities. The ED group had less incidences of readmission than the comparison group. (Crude hazard ratio = 0.73, and adjusted HR = 0.75, both p < 0.001). Overall, the cumulative incidences of readmission in the ED group (9.5%) were lower than those in the comparison group (12.8%, p < 0.001), whereas reoperations were insignificantly different (1.5% vs. 1.2%, p = 0.189). For patients aged 50–70 years and who require lumbar fusion surgery, ED could yield a 25% reduced risk of readmission for any cause within 180 days post-operation. Since the reoperation rates remained similar, our results suggest that ED may be a promising option for elderly patients undergoing lumbar spinal fusion surgery.

Comparison of Stand-alone Lateral Lumbar Interbody Fusion Versus Open Laminectomy and Posterolateral Instrumented Fusion in the Treatment of Adjacent Segment Disease Following Previous Lumbar Fusion Surgery

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

The aim of this study was to compare clinical and radiographic outcomes of patients who underwent stand-alone lateral lumbar interbody fusion (LLIF) to those who underwent posterolateral fusion (PLF) for symptomatic adjacent segment disease (ASD).

SUMMARY OF BACKGROUND DATA

Recent studies have suggested that LLIF can successfully treat ASD; however, there are no studies to date that compare LLIF with the traditional open PLF in this cohort.

METHODS

A total of 47 consecutive patients who underwent LLIF or PLF for symptomatic ASD between January 2007 and August 2016 after failure of conservative management were reviewed for this study. Patient-reported outcomes (PROs) were collected on all patients at preoperative, postoperative, and most recent post-operative visit using the Oswestry Disability Index, Visual Analog Scale (VAS)-Back, and VAS-Leg surveys. Preoperative, immediate postoperative, and most recent postoperative radiographs were assessed for pelvic incidence, fusion, intervertebral disc height, segmental and overall lumbar lordosis (LL). Symptomatic ASD was diagnosed if back pain, neurogenic claudication, or lower extremity radiculopathy presented following a previous lumbar fusion. Preoperative plain radiographs were evaluated for evidence of adjacent segment degeneration.

RESULTS

A total of 47 patients (23 LLIF, 24 PLF) met inclusion criteria. Operative times (P < 0.001) and intraoperative blood loss (P < 0.001) were significantly higher in the PLF group. Patients who underwent PLF were discharged approximately 3 days after the LLIF patients (P < 0.001). PROs in the PLF and LLIF cohorts showed significant and equivalent improvement, with equivalent radiographic fusion rates. LLIF significantly improve segmental lordosis (P < 0.001), total LL (P = 0.003), and disc height (P < 0.001) from preoperative to immediate postoperative and final follow-up (P = 0.004, P = 0.019, P ≤ 0.001, respectively).

CONCLUSION

Although LLIF may provide less perioperative morbidity and shorter length of hospitalization, both techniques are safe and effective approaches to restore radiographic alignment and provide successful clinical outcomes in patients with adjacent segment degeneration following previous lumbar fusion surgery.

LEVEL OF EVIDENCE

3.

Biomechanical Analysis of Stand-alone Lateral Lumbar Interbody Fusion for Lumbar Adjacent Segment Disease

Study design

Biomechanical cadaveric study 

Objective

To compare biomechanical properties of a single stand-alone interbody fusion and a single-level pedicle screw construct above a previous lumbar pedicle fusion.

Summary of background data

Adjacent segment disease (ASD) is spondylosis of adjacent vertebral segments after previous spinal fusion. Despite the consensus that ASD is clinically significant, the surgical treatment of ASD is controversial.

Methods

Lateral lumbar interbody fusion (LLIF) and posterior spinal fusion (PSF) with pedicle screws were analyzed within a validated cadaveric lumbar fusion model. L3-4 vertebral segment motion was analyzed within the following simulations: without implants (intact), L3-4 LLIF-only, L3-4 LLIF with previous L4-S1 PSF, L3-4 PSF with previous L4-S1 PSF, and L4-S1 PSF alone. L3-4 motion values were measured during flexion/extension with and without axial load, side bending, and axial rotation.

Results

L3-4 motion in the intact model was found to be 4.7 ± 1.2 degrees. L3-4 LLIF-only decreased motion to 1.9 ± 1.1 degrees. L3-4 LLIF with previous L4-S1 fusion demonstrated less motion in all planes with and without loading (p < 0.05) compared to an intact spine. However, L3-4 motion with flexion/extension and lateral bending was noted to be greater compared to the L3-S1 construct (p < 0.5). The L3-S1 PSF construct decreased motion to less than 1° in all planes of motion with or without loading (p < 0.05). The L3-4 PSF with previous L4-S1 PSF constructs decreased the flexion/extension motion by 92.4% compared to the intact spine, whereas the L3-4 LLIF with previous L4-S1 PSF constructs decreased motion by 61.2%.

Conclusions

Stand-alone LLIF above a previous posterolateral fusion significantly decreases motion at the adjacent segment, demonstrating its utility in treating ASD without necessitating revision. The stand-alone LLIF is a biomechanically sound option in the treatment of ASD and is advantageous in patient populations who may benefit from less invasive surgical options.

Novel Application of a New Lateral System for Adjacent-level Revision Surgery: A Case Report

In recent years, lateral lumbar interbody fusion (LLIF) has grown in popularity as a minimally invasive spine surgery (MISS) approach that can be offered to patients with prior surgeries from a posterior approach. In this report, we present a patient with a focal disease and a history of multiple posterior lumbar surgeries who underwent LLIF with a novel application of the Duo^TM system (Spineology Inc., MN, USA) adjacent to prior surgical levels and without posterior instrumentation. At one year postoperatively, she continued to have no back pain or complaints relating to her lumbar pathology. The case demonstrates the novel use of a new MISS LLIF system that requires minimal exposure as compared to current LLIF systems to treat a patient with adjacent segment disease and progressive symptoms following multiple posterior decompressive surgeries.

Long Term Outcomes and Effects of Surgery on Degenerative Spinal Deformity: A 14-Year National Cohort Study

Degenerative spinal deformity (DSD) has become a prevalent cause of disability and pain among the aging population worldwide. Though surgery has emerged as a promising option for DSD, the natural course, outcomes, and effects of surgery on DSD have remained elusive. This cohort study used a national database to comprehensively follow up patients of DSD for all-cause mortality, respiratory problems, and hip fracture-related hospitalizations. All patients were grouped into an operation or a non-operation group for comparison. An adjustment of demographics, comorbidities, and propensity-score matching was conducted to ameliorate confounders. A Cox regression hazard ratio (HR) model and Kaplan-Meier analysis were also applied. The study comprised 21,810 DSD patients, including 12,544 of the operation group and 9266 of the non-operation group. During the 14 years (total 109,591.2 person-years) of follow-up, the operation group had lower mortality (crude hazard ratio = 0.40), lower respiratory problems (cHR = 0.45), and lower hip fractures (cHR = 0.63) than the non-operation group (all p < 0.001). After adjustment, the risks for mortality and respiratory problems remained lower (adjusted HR = 0.60 and 0.65, both p < 0.001) in the operation than the non-operation group, while hip fractures were indifferent (aHR = 1.08, p > 0.05). Therefore, surgery for DSD is invaluable since it could reduce the risks of mortality and of hospitalization for respiratory problems.

Assessing the Difference in Clinical and Radiologic Outcomes Between Expandable Cage and Nonexpandable Cage Among Patients Undergoing Minimally Invasive Transforaminal Interbody Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Minimally invasive transforaminal interbody fusion (MIS-TLIF) has been shown to have excellent outcomes for surgical management of degenerative disc disease. However, the challenge is in addressing coronal imbalance and restoring lumbar lordosis and sagittal alignment. Use of expandable cages in MIS-TLIF has been hypothesized to circumvent this disadvantage. An indirect meta-analysis of the evidence is presented comparing outcomes from expandable cages with those from nonexpandable cages, in patients undergoing MIS-TLIF.

METHODS

PRISMA guidelines were used to conduct a systematic review and meta-analysis to compare the clinical and radiologic outcomes of expandable cages and nonexpandable cages in patients undergoing MIS-TLIF.

RESULTS

Twelve studies (706 patients) were included in the meta-analysis. The mean increase in disc height was found to be significantly greater for the nonexpandable cages group than for the expandable cages group (1.33 mm; 95% confidence interval [CI], 1.28-1.38 vs. 1.14 mm,; 95% CI, 1.06-1.23; P < 0.001). No significant difference was found regarding change in lumbar lordosis at last follow-up between the 2 groups (P = 0.34). The mean change in segmental lordosis was found to be significantly higher for the expandable cage group (5.04°, 95% CI, 3.89-6.20 vs. 2.08°, 95% CI, 1.93-2.22; P < 0.001). We did not detect any significant difference in fusion rate (P = 0.33), subsidence rate (P = 0.41) or in reoperations (P = 0.56) at last follow-up between the 2 groups.

CONCLUSIONS

Our results indicate that there may not be a significant difference in clinical and radiologic parameters between expandable cages and nonexpandable cages among patients undergoing MIS-TLIF, and it is unclear if the higher cost of the expandable cages is justified.

Complications for minimally invasive lateral interbody arthrodesis: a systematic review and meta-analysis comparing prepsoas and transpsoas approaches

OBJECTIVE

Minimally invasive anterolateral retroperitoneal approaches for lumbar interbody arthrodesis have distinct advantages attractive to spine surgeons. Prepsoas or transpsoas trajectories can be employed with differing complication profiles because of the inherent anatomical differences encountered in each approach. The evidence comparing them remains limited because of poor quality data. Here, the authors sought to systematically review the available literature and perform a meta-analysis comparing the two techniques.

METHODS

A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A database search was used to identify eligible studies. Prepsoas and transpsoas studies were compiled, and each study was assessed for inclusion criteria. Complication rates were recorded and compared between approach groups. Studies incorporating an analysis of postoperative subsidence and pseudarthrosis rates were also assessed and compared.

RESULTS

For the prepsoas studies, 20 studies for the complications analysis and 8 studies for the pseudarthrosis outcomes analysis were included. For the transpsoas studies, 39 studies for the complications analysis and 19 studies for the pseudarthrosis outcomes analysis were included. For the complications analysis, 1874 patients treated via the prepsoas approach and 4607 treated with the transpsoas approach were included. In the transpsoas group, there was a higher rate of transient sensory symptoms (21.7% vs 8.7%, p = 0.002), transient hip flexor weakness (19.7% vs 5.7%, p < 0.001), and permanent neurological weakness (2.8% vs 1.0%, p = 0.005). A higher rate of sympathetic nerve injury was seen in the prepsoas group (5.4% vs 0.0%, p = 0.03). Of the nonneurological complications, major vascular injury was significantly higher in the prepsoas approach (1.8% vs 0.4%, p = 0.01). There was no difference in urological or peritoneal/bowel injury, postoperative ileus, or hematomas (all p > 0.05). A higher infection rate was noted for the transpsoas group (3.1% vs 1.1%, p = 0.01). With regard to postoperative fusion outcomes, similar rates of subsidence (12.2% prepsoas vs 13.8% transpsoas, p = 0.78) and pseudarthrosis (9.9% vs 7.5%, respectively, p = 0.57) were seen between the groups at the last follow-up.

CONCLUSIONS

Complication rates vary for the prepsoas and transpsoas approaches owing to the variable retroperitoneal anatomy encountered during surgical dissection. While the risks of a lasting motor deficit and transient sensory disturbances are higher for the transpsoas approach, there is a reciprocal reduction in the risks of major vascular injury and sympathetic nerve injury. These results can facilitate informed decision-making and tailored surgical planning regarding the choice of minimally invasive anterolateral access to the spine.

Biomechanical evaluation of lumbar lateral interbody fusion for the treatment of adjacent segment disease

BACKGROUND CONTEXT

Adjacent segment disease (ASD) is a well-known complication after lumbar fusion. Lumbar lateral interbody fusion (LLIF) may provide an alternative method of treatment for ASD while avoiding the morbidity associated with revision surgery through a traditional posterior approach. This is the first biomechanical study to evaluate the stability of lateral-based constructs for treating ASD in existing multilevel fusion model.

PURPOSE

We aimed to evaluate the biomechanical stability of anterior column reconstruction through the less invasive lateral-based interbody techniques compared with traditional posterior spinal fusion for the treatment of ASD in existing multilevel fusion.

STUDY DESIGN/SETTING

Cadaveric biomechanical study of laterally based interbody strategies for treating ASD.

METHODS

Eighteen fresh-frozen cadaveric specimens were nondestructively loaded in flexion, extension, and lateral bending. The specimens were randomized into three different groups according to planned posterior spinal instrumented fusion (PSF): group 1: L5-S1, group 2: L4-S1, and group 3: L3-S1. In each group, ASD was considered the level cranial to the upper-instrumented vertebrae (UIV). After testing the intact spine, each specimen underwent PSF representing prior fusion in the ASD model. The adjacent segment for each specimen then underwent (1) Stand-alone LLIF, (2) LLIF + plate, (3) LLIF + single screw rod (SSR) anterior instrumentation, and (4) LLIF + traditional posterior extension of PSF. In all conditions, three-dimensional kinematics were tracked, and range of motion (ROM) was calculated for the comparisons.

RESULTS

ROM results were expressed as a percentage of the intact spine ROM. LLIF effectively reduces ROM in all planes of ROM. Supplementation of LLIF with plate or SSR provides further stability as compared with stand-alone LLIF. Expansion of posterior instrumentation provides the most substantial stability in all planes of ROM (p <.05). All constructs demonstrated a consistent trend of reduction in ROM between all the groups in all bending motions.

CONCLUSIONS

This biomechanical study suggests potential promise in exploring LLIF as an alternative treatment of ASD but reinforces previous studies' findings that traditional expansion of posterior instrumentation provides the most biomechanically stable construct.

Stand-alone lateral lumbar interbody fusion for the treatment of symptomatic adjacent segment degeneration following previous lumbar fusion

BACKGROUND CONTEXT

Revision posterior decompression and fusion surgery for patients with symptomatic adjacent segment degeneration (ASD) is associated with significant morbidity and is technically challenging. The use of a stand-alone lateral lumbar interbody fusion (LLIF) in patients with symptomatic ASD may prevent many of the complications associated with revision posterior surgery.

PURPOSE

The objective of this study was to assess the clinical and radiographic outcomes of patients who underwent stand-alone LLIF for symptomatic ASD.

STUDY DESIGN

This is a retrospective case series.

PATIENT SAMPLE

We retrospectively reviewed patients with a prior posterior instrumented fusion who underwent a subsequent stand-alone LLIF for ASD by a single surgeon. All patients had at least 18 months of follow-up. Patients were diagnosed with symptomatic ASD if they had a previous lumbar fusion with the subsequent development of back pain, neurogenic claudication, or lower extremity radiculopathy in the setting of imaging, which demonstrated stenosis, spondylolisthesis, kyphosis, or scoliosis at the adjacent level.

OUTCOME MEASURES

Patient-reported outcomes were obtained at preoperative and final follow-up visits using the Oswestry Disability Index [ODI], visual analog scale (VAS)-back, and VAS-leg. Radiographic parameters were measured, including segmental and overall lordoses, pelvic incidence-lumbar lordosis mismatch, coronal alignment, and intervertebral disc height.

METHODS

Clinical and radiographic outcomes were compared between preoperative and final follow-up using paired t tests.

RESULTS

Twenty-five patients met inclusion criteria. The mean age was 62.0±11.3 years. The average follow-up was 34.8±22.4 months. Fifteen (60%) underwent stand-alone LLIF surgery for radicular leg pain, 7 (28%) for symptoms of claudication, and 25 (100.0%) for severe back pain. Oswestry Disability Index scores significantly improved from preoperative values (46.6±16.4) to final follow-up (30.4±16.8, p=.002). Visual analog scale-back (preop 8.4±1.0, postop 3.2±1.9; p<.001), and VAS-leg (preop 3.6±3.4, postop 1.9±2.6; p<.001) scores significantly improved following surgery. Segmental and regional lordoses, as well as intervertebral disc height, significantly improved (p<.001) and remained stable (p=.004) by the surgery. Pelvic incidence-lumbar lordosis mismatch significantly improved at the first postoperative visit (p=.029) and was largely maintained at the most recent follow-up (p=.45). Six patients suffered from new-onset thigh weakness following LLIF surgery, but all showed complete resolution within 6 weeks. Three patients required subsequent additional surgeries, all of which were revised to include posterior instrumentation.

CONCLUSIONS

Stand-alone LLIF is a safe and effective approach with low morbidity and acceptable complication rates for patients with symptomatic ASD following a previous lumbar fusion.

Therapeutic effect of MIPPSO in the thoracolumbar vertebra fracture

The purpose of this study was to compare the efficacy of minimally invasive percutaneous pedicle screw osteosynthesis (MIPPSO) and traditional open pedicle screw osteosynthesis (TOPSO) in the treatment of thoracolumbar vertebra fracture. A retrospective case-control study was conducted in 120 patients with thoracolumbar vertebral fractures treated in the Affiliated Jiangyin Hospital of Southeast University Medical School (Jiangyin, China) from January 2013 to September 2014. They were randomly divided into two groups: MIPPSO and TOPSO groups with 60 cases in each group. The operation time, blood loss, incision length, post-operative bed rest time, hospital stay, visual analogue scale (VAS) pain scores and Oswestry disability index (ODI) scores before and after operation were recorded and analyzed. Inflammatory indexes including serum C-reactive protein (CRP) and creatine kinase (CK), the anterior vertebral height ratio and kyphosis Cobb's angle changes were also observed. The basic data of the two groups were similar, and there was no significant difference in the operation time between the two groups. The perioperative blood loss, length of incision, bed rest time and total hospital stay in the minimally invasive group were less than those in the open group. Levels of post-operative inflammation indicators such as CRP and CK were significantly higher than those of pre-operative (P<0.05), which was more obvious in the TOPSO group (P<0.05). VAS, ODI scores, anterior vertebral height and Cobb's angle were significantly improved at three days, one and 12 months after surgery compared with those before operation. MIPPSO for the treatment of thoracolumbar fractures can achieve similar clinical effects with traditional incision surgery. In addition, it has the advantages of less trauma, less bleeding and shorter post-operative bed rest time and hospital stay.

Comparison of Stand-Alone, Transpsoas Lateral Interbody Fusion at L3-4 and Cranial vs Transforaminal Interbody Fusion at L3-4 and L4-5 for the Treatment of Lumbar Adjacent Segment Disease

Study Design

Retrospective cohort study.

Objective

To compare outcomes and complications of stand-alone minimally invasive lateral interbody fusion (LIF) vs revision posterior surgery for the treatment of lumbar adjacent segment disease.

Methods

Adults who underwent LIF or transforaminal lumbar interbody fusion (TLIF) for adjacent segment disease were compared. Exclusion criteria: >grade 1 spondylolisthesis, posterior approach after LIF, and L5/S1 surgery. Patient demographics, estimated blood loss, hospital length of stay, complications, reoperations, health-related quality of life measures, and radiographs were examined. Data were analyzed with the χ², Wilcoxon signed rank, and Mann-Whitney U tests.

Results

A total of 17 LIF and 16 TLIF patients were included. Demographics were similar. Follow up was similar (LIF: 22.9 ± 11.8 months vs TLIF: 22.0 ± 4.6 months; P = .86). The LIF patients had significantly less blood loss (LIF: 36 ± 16 mL vs TLIF: 700 ± 767 mL; P < .001) and shorter length of stay (LIF: 2.6 ± 2.9 days vs TLIF: 3.3 ± 0.9 days; P = .001). There were no intraoperative complications. Revision rate was 4 of 17 in LIF and 3 of 16 in TLIF (P = .73). Baseline health-related quality of life and radiographic measurements were similar. In both groups, back and leg pain scores significantly improved, and in LIF, the Owestry Disability Index, and EuroQol-5D significantly improved. The LIF had a significant increase in intervertebral height (LIF: 4.8 ± 2.9 mm, P < .001, TLIF: 1.3 ± 3.4 mm, P = .37), which was significantly greater for LIF than TLIF (P = .002). Similarly, LIF had a significant increase in segmental lordosis (LIF: 5.6° ± 4.9°, P < .001, TLIF: 3.6° ± 8.6°, P = .16), which was not significantly different between groups.

Conclusions

Patients with adjacent segment disease may receive significant benefit from stand-alone LIF or TLIF. The LIF offers advantages of less blood loss and a shorter hospital stay.

Level of Evidence

3.

Stand-Alone Anterolateral Interbody Fusion Versus Extended Posterior Fusion for Symptomatic Adjacent-Segment Degeneration: A Retrospective Study of 2 Years' Follow-up

OBJECTIVE

To evaluate the clinical and radiologic outcome of stand-alone anterolateral lumbar interbody fusion (ALLIF) using self-locked cages in comparison with extended posterior lumbar interbody fusion (PLIF) for symptomatic adjacent-segment degeneration (ASD) after posterior lumbar fusion.

METHODS

This retrospective study enrolled 40 symptomatic patients with ASD who were treated with ALLIF (n = 13) or extended PLIF (n = 27) between January 2011 and January 2015. Evaluations were performed preoperatively, at 3, 12, and 24 months postoperatively. Clinical outcome measurements included visual analog scale scores for low-back and leg pain, Oswestry Disability Index score for function assessment, Short-Form 36 Questionnaire for quality of life, and modified Macnab criteria for patient satisfaction. Radiologic outcome measurements included fusion rate, cage subsidence, disc height, and lumbar lordosis.

RESULTS

There were no significant differences in the baseline data for the ALLIF and PLIF groups (P > 0.05). Mean operative time, blood loss, and length of hospital stay were significantly decreased for the ALLIF group (P < 0.05). Postoperatively, low back and leg pain was relieved, function and quality of life were improved in both groups (P < 0.05), whereas disc height and lumbar lordosis were restored (P < 0.05). At 24-month follow-up, fusion was observed in 13 of 13 patients (100%), with 3 of 13 (23.1%) patients developing cage subsidence in the ALLIF group.

CONCLUSIONS

Stand-alone ALLIF could achieve satisfactory safety and efficacy for the treatment of symptomatic ASD with less trauma and faster recovery, and it may serve as an alternative surgical treatment for symptomatic ASD with appropriate indication.

Hydrogen peroxide induces programmed necrosis in rat nucleus pulposus cells through the RIP1/RIP3-PARP-AIF pathway

This study aimed to systematically investigate whether programmed necrosis contributes to H2 O2 -induced nucleus pulposus (NP) cells death and to further explore the underlying mechanism involved. Rat NP cells were subjected to different concentrations of H2 O2 for various time periods. The cell viability was measured using a cell counting kit-8, and the death rate was detected by Hoechst 33258/propidium iodide (PI) staining. The programmed necrosis-related molecules receptor-interacting protein 1 (RIP1), receptor-interacting protein 3 (RIP3), poly (ADP-ribose) polymerase (PARP), and apoptosis inducing factor (AIF) were determined by real-time polymerase chain reaction and Western blotting, respectively. The morphologic and ultrastructural changes were examined by phasecontrast microscopy and transmission electron microscopy (TEM). In addition, the necroptosis inhibitor Necrostatin-1 (Nec-1), the PARP inhibitor diphenyl-benzoquinone (DPQ) and small interfering RNA (siRNA) technology were used to indirectly evaluate programmed necrosis. Our results indicated that H2 O2 induced necrotic morphologic and ultrastructural changes and an elevated PI positive rate in NP cells; these effects were mediated by the upregulation of RIP1 and RIP3, hyperactivation of PARP, and translocation of AIF from mitochondria to nucleus. Additionally, NP cells necrosis was significantly attenuated by Nec-1, DPQ pretreatment and knockdown of RIP3 and AIF, while knockdown of RIP1 produced the opposite effects. In conclusion, these results suggested that under oxidative stress, RIP1/RIP3-mediated programmed necrosis, executed through the PARP-AIF pathway, played an important role in NP cell death. Protective strategies aiming to regulate programmed necrosis may exert a beneficial effect for NP cells survival, and ultimately retard intervertebral disc (IVD) degeneration. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1269-1282, 2018.

Effectiveness of Reoperations for Adjacent Segment Disease Following Lumbar Spinal Fusion

Although several options are available to address adjacent segment disease (ASD), the most effective surgical treatment has not been determined. In addition, it is important to subdivide ASD into stenosis with or without instability to determine if a decompression alone vs an extension of fusion is necessary. A systematic search of multiple medical reference databases was conducted for studies on surgical treatment of ASD. The primary outcome measures used were radiographic and clinical success rates. Meta-analysis was completed to determine effect summary values, 95% confidence intervals, and Q statistic and I² values, using the random effects model for heterogeneity. The search yielded 662 studies, of which 657 were excluded. A total of 5 (level IV) studies with a total of 118 patients were included in this review. In 2 studies (46 patients), stenosis without instability was the indication for reoperation for ASD. However, extension of fusion was the modality of choice for the treatment of ASD in all studies. Overall clinical improvement (in back and/or leg pain scores) was noted in 71.3% of patients (95% confidence interval, 37.4-100), while radiographic fusion was noted in 89.3% of patients (95% confidence interval, 51.2-100). Following reoperation for ASD, revision surgery rates ranged from 4.5% to 23.1% at last clinical follow-up. There is variability in the clinical improvement following lumbar fusion for ASD. In addition, little literature exists regarding the optimal treatment options for patients with ASD for stenosis with or without instability. [Orthopedics. 2018; 41(2):e161-e167.].

Salvage Strategy for Failed Spinal Fusion Surgery Using Lumbar Lateral Interbody Fusion technique: A Technical Note

INTRODUCTION

Failed spinal fusion surgery sometimes requires salvage surgery when symptomatic, especially with postsurgical decrease in intervertebral disc height followed by foraminal stenosis. For such cases, an anterior approach to lumbar lateral interbody fusion (LLIF) provides safe, direct access to the pathological disc space and a potential improvement in the fusion rate. One LLIF approach, oblique lateral interbody fusion (OLIF), targets the oblique lateral window of the intervertebral discs to achieve successful lateral interbody fusion. The current technical note describes spinal revision surgery using the OLIF procedure.

TECHNICAL NOTE

The subjects were patients with leg pain and/or lower back pain derived from decreased intervertebral height followed by foraminal stenosis due to failed spinal fusion surgery. These patients underwent additional OLIF surgery and posterior fusion with no additional posterior direct decompression. Their outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scores at baseline and final follow-up. Bony union was also evaluated using computed tomography images at final follow-up. Six subjects were evaluated, with two representative cases described in detail. Four patients had an adjacent segment disorder, and the other two patients had pseudarthrosis due to postoperative infection. The mean JOA score improved from 5.7 ± 5.4 to 21.2 ± 2.3, with a mean recovery rate of 65.0%. All cases showed intervertebral bony union.

CONCLUSIONS

We introduced a salvage strategy for failed posterior spine fusion surgery cases using the OLIF procedure. Patients effectively achieved recovered intervertebral and foraminal height with no additional posterior direct decompression.

Lateral Lumbar Interbody Fusion and in Situ Screw Fixation for Rostral Adjacent Segment Stenosis of the Lumbar Spine

Objective

The purpose of this study is to describe the detailed surgical technique and short-term clinical and radiological outcomes of lateral lumbar interbody fusion (LLIF) and in situ lateral screw fixation using a conventional minimally invasive screw fixation system (MISF) for revision surgery to treat rostral lumbar adjacent segment disease.

Methods

The medical and radiological records were retrospectively reviewed. The surgery was indicated in 10 consecutive patients with rostral adjacent segment stenosis and instability. After the insertion of the interbody cage, lateral screws were inserted into the cranial and caudal vertebra using the MISF through the same LLIF trajectory. The radiological and clinical outcomes were assessed preoperatively and at 1, 3, 6, and 12 months postoperatively.

Results

The median follow-up period was 13 months (range, 3–48 months). Transient sensory changes in the left anterior thigh occurred in 3 patients, and 1 patient experienced subjective weakness; however, these symptoms normalized within 1 week. Back and leg pain were significantly improved (p<0.05). In the radiological analysis, both the segmental angle at the operated segment and anterior disc height were significantly increased. At 6 months postoperatively, solid bony fusion was confirmed in 7 patients. Subsidence and mechanical failure did not occur in any patients.

Conclusion

This study demonstrates that LLIF and in situ lateral screw fixation may be an alternative surgical option for rostral lumbar adjacent segment disease.

Multidisciplinary Evaluation Leads to the Decreased Utilization of Lumbar Spine Fusion: An Observational Cohort Pilot Study

STUDY DESIGN

Observational cohort pilot study.

OBJECTIVE

To determine the impact of a multidisciplinary conference on treatment decisions for lumbar degenerative spine disease.

SUMMARY OF BACKGROUND DATA

Multidisciplinary decision making improves outcomes in many disciplines. The lack of integrated systems for comprehensive care for spinal disorders has contributed to the inappropriate overutilization of spine surgery in the United States.

METHODS

We implemented a multidisciplinary conference involving physiatrists, anesthesiologists, pain specialists, neurosurgeons, orthopaedic spine surgeons, physical therapists, and nursing staff. Over 10 months, we presented patients being considered for spinal fusion or who had a complex history of prior spinal surgery. We compared the decision to proceed with surgery and the proposed surgical approach proposed by outside surgeons with the consensus of our multidisciplinary conference. We also assessed comprehensive demographics and comorbidities for the patients and examined outcomes for surgical patients.

RESULTS

A total of 137 consecutive patients were reviewed at our multidisciplinary conference during the 10-month period. Of these, 100 patients had been recommended for lumbar spine fusion by an outside surgeon. Consensus opinion of the multidisciplinary conference advocated for nonoperative management in 58 patients (58%) who had been previously recommended for spinal fusion at another institution (χ  = 26.6; P < 0.01). Furthermore, the surgical treatment plan was revised as a product of the conference in 28% (16 patients) of the patients who ultimately underwent surgery (χ  = 43.6; P < 0.01). We had zero 30-day complications in surgical patients.

CONCLUSION

Isolated surgical decision making may result in suboptimal treatment recommendations. Multidisciplinary conferences can reduce the utilization of lumbar spinal fusion, possibly resulting in more appropriate use of surgical interventions with better candidate selection while providing patients with more diverse nonoperative treatment options. Although long-term patient outcomes remain to be determined, such multidisciplinary care will likely be essential to improving the quality and value of spine care.

LEVEL OF EVIDENCE

3.

Biomechanical analysis of lateral interbody fusion strategies for adjacent segment degeneration in the lumbar spine

BACKGROUND CONTEXT

Surgical treatment of symptomatic adjacent segment disease (ASD) typically involves extension of previous instrumentation to include the newly affected level(s). Disruption of the incision site can present challenges and increases the risk of complication. Lateral-based interbody fusion techniques may provide a viable surgical alternative that avoids these risks. This study is the first to analyze the biomechanical effect of adding a lateral-based construct to an existing fusion.

PURPOSE

The study aimed to determine whether a minimally invasive lateral interbody device, with and without supplemental instrumentation, can effectively stabilize the rostral segment adjacent to a two-level fusion when compared with a traditional posterior revision approach.

STUDY DESIGN/SETTING

This is a cadaveric biomechanical study of lateral-based interbody strategies as add-on techniques to an existing fusion for the treatment of ASD.

METHODS

Twelve lumbosacral specimens were non-destructively loaded in flexion, extension, lateral bending, and torsion. Sequentially, the tested conditions were intact, two-level transforaminal lumbar interbody fusion (TLIF) (L3-L5), followed by lateral lumbar interbody fusion procedures at L2-L3 including interbody alone, a supplemental lateral plate, a supplemental spinous process plate, and then either cortical screw or pedicle screw fixation. A three-level TLIF was the final instrumented condition. In all conditions, three-dimensional kinematics were tracked and range of motion (ROM) was calculated for comparisons. Institutional funds (<$50,000) in support of this work were provided by Medtronic Spine.

RESULTS

The addition of a lateral interbody device superadjacent to a two-level fusion significantly reduced motion in flexion, extension, and lateral bending (p<.05). Supplementing with a lateral plate further reduced ROM during lateral bending and torsion, whereas a spinous process plate further reduced ROM during flexion and extension. The addition of posterior cortical screws provided the most stable lateral lumbar interbody fusion construct, demonstrating ROM comparable with a traditional three-level TLIF.

CONCLUSIONS

The data presented suggest that a lateral-based interbody fusion supplemented with additional minimally invasive instrumentation may provide comparable stability with a traditional posterior revision approach without removal of the existing two-level rod in an ASD revision scenario.

Clinical outcomes after minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion for treatment of degenerative lumbar disease: a systematic review and meta-analysis

The surgical procedures used for arthrodesis in the lumbar spine for degenerative lumbar diseases remain controversial. This systematic review aims to assess and compare clinical outcomes along with the complications and fusion of each technique (minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) or minimally invasive lateral lumbar interbody fusion (MIS LLIF)) for treatment of degenerative lumbar diseases. Relevant studies were identified from Medline and Scopus from inception to July 19, 2016 that reported Oswestry Disability Index (ODI), back and leg pain visual analog score (VAS), postoperative complications, and fusion of either technique. Fifty-eight studies were included for the analysis of MIS-TLIF; 40 studies were included for analysis of LLIF, and 1 randomized controlled trial (RCT) study was included for comparison of MIS-TLIF to LLIF. Overall, there were 9506 patients (5728 in the MIS-TLIF group and 3778 in the LLIF group). Indirect meta-analysis, MIS-TLIF provided better postoperative back and leg pain (VAS), disabilities (ODI), and risk of having complications when compared to LLIF technique, but the fusion rate was not significantly different between the two techniques. However, direct meta-analysis between RCT study and pooled indirect meta-analysis of MIS-TLIF have better pain, disabilities, and complication but no statistically significant difference when compared to LLIF. In LLIF, the pooled mean ODI and VAS back pain were 2.91 (95% CI 2.49, 3.33) and 23.24 (95% CI 18.96, 27.51) in MIS approach whereas 3.14 (95% CI 2.29, 4.04) and 28.29 (95% CI 21.92, 34.67) in traditional approach. In terms of complications and fusion rate, there was no difference in both groups. In lumbar interbody fusion, MIS-TLIF had better ODI, VAS pain, and complication rate when compared to LLIF with direct and indirect meta-analysis methods. However, in terms of fusion rates, there were no differences between the two techniques.

Extreme lateral lumbar interbody fusion: Do the cons outweigh the pros?

BACKGROUND

Major factors prompted the development of minimally invasive (MIS) extreme lateral interbody fusion (XLIF; NuVasive Inc., San Diego, CA, USE) for the thoracic/lumbar spine. These include providing interbody stabilization and indirect neural decompression while avoiding major visceral/vessel injury as seen with anterior lumbar interbody fusion (ALIF), and to avert trauma to paraspinal muscles/facet joints found with transforaminal lumbar interbody fusion (TLIF), posterior lumbar interbody fusion (PLIF), and posterior-lateral fusion techniques (PLF). Although anticipated pros of MIS XLIF included reduced blood loss, operative time, and length of stay (LOS), they also included, higher fusion, and lower infection rates. Unanticipated cons, however, included increased morbidity/mortality rates.

METHODS

We assessed the pros and cons (e.g., risks, complications, comparable value/superiority/inferiority, morbidity/mortality) of MIS XLIF vs. ALIF, TLIF, PLIF, and PLF.

RESULTS

Pros of XLIF included various biomechanical and technical surgical advantages, along with multiple cons vs. ALIF, TLIF, PLIF, and PLF. For example, XLIF correlated with a considerably higher frequency of major neurological deficits vs. other constructs; plexus injuries 13.28%, sensory deficits 0-75% (permanent in 62.5%), motor deficits 0.7-33.6%, and anterior thigh pain 12.5-25%. XLIF also disproportionately contributed to other major morbidity/mortality; sympathectomy, major vascular injuries (some life-ending others life-threatening), bowel perforations, and seromas. Furthermore, multiple studies documented no superiority, and the potential inferiority of XLIF vs. ALIF, TLIF, PLIF, and PLF.

CONCLUSION

Reviewing the pros of XLIF (e.g. radiographic, technical, biomechanical) vs. the cons (inferiority, increased morbidity/mortality) vs. ALIF, TLIF, PLIF, and PLF, we question whether XLIF should remain part of the lumbar spinal surgical armamentarium.

Stand-alone LLIF Lateral Cage Migration: A Case Report

Lateral approaches to the lumbar disc space have become popular in recent years with very few reported complications. We report on a rare case of a stand-alone cage migration. A 77-year-old female presented with a right L2-3 radiculopathy that was refractory to maximum medical management. This was secondary to foraminal compression at L2-3 and L3-4 due to degenerative disc disease and levoscoliosis, as well as Grade 1 spondylolisthesis at both levels. A left-sided approach lateral lumbar interbody fusion was performed at L2-3 and L3-4 using a lordotic polyetheretherketone (PEEK) graft (50 mm length x 18 mm width x 9 mm height) packed with demineralized bone matrix (DBM). A contralateral release of the annulus fibrosis was performed during the decompression prior to graft insertion. Postoperative anteroposterior and lateral x-ray imaging confirmed good position of interbody grafts, correction of scoliosis as well as spondylolisthesis, and restoration of disc height achieving foraminal indirect decompression. A routine postoperative x-ray at three months demonstrated asymptomatic ipsilateral cage migration at the L2-3 level with evidence of arthrodesis in the disc space. This was managed conservatively without further surgical intervention. Placement of a lateral plate or interbody intradiscal plating system in patients with scoliosis and significant coronal deformity is an option that can be considered to prevent this rare LLIF complication. Moreover, asymptomatic cage migration may be conservatively managed without reoperation.

Comparison of complication rates of minimally invasive transforaminal lumbar interbody fusion and lateral lumbar interbody fusion: a systematic review of the literature

OBJECT Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and lateral lumbar interbody fusion (LLIF) are 2 currently popular techniques for lumbar arthrodesis. The authors compare the total risk of each procedure, along with other important complication outcomes. METHODS This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies (up to May 2015) that reported complications of either MI-TLIF or LLIF were identified from a search in the PubMed database. The primary outcome was overall risk of complication per patient. Secondary outcomes included risks of sensory deficits, temporary neurological deficit, permanent neurological deficit, intraoperative complications, medical complications, wound complications, hardware failure, subsidence, and reoperation. RESULTS Fifty-four studies were included for analysis of MI-TLIF, and 42 studies were included for analysis of LLIF. Overall, there were 9714 patients (5454 in the MI-TLIF group and 4260 in the LLIF group) with 13,230 levels fused (6040 in the MI-TLIF group and 7190 in the LLIF group). A total of 1045 complications in the MI-TLIF group and 1339 complications in the LLIF group were reported. The total complication rate per patient was 19.2% in the MI-TLIF group and 31.4% in the LLIF group (p < 0.0001). The rate of sensory deficits and temporary neurological deficits, and permanent neurological deficits was 20.16%, 2.22%, and 1.01% for MI-TLIF versus 27.08%, 9.40%, and 2.46% for LLIF, respectively (p < 0.0001, p < 0.0001, p = 0.002, respectively). Rates of intraoperative and wound complications were 3.57% and 1.63% for MI-TLIF compared with 1.93% and 0.80% for LLIF, respectively (p = 0.0003 and p = 0.034, respectively). No significant differences were noted for medical complications or reoperation. CONCLUSIONS While there was a higher overall complication rate with LLIF, MI-TLIF and LLIF both have acceptable complication profiles. LLIF had higher rates of sensory as well as temporary and permanent neurological symptoms, although rates of intraoperative and wound complications were less than MI-TLIF. Larger, prospective comparative studies are needed to confirm these findings as the current literature is of relative poor quality.