Interbody Device Research Articles

Cervical Disc Arthroplasty Device Failure Causing Progressive Cervical Myelopathy and Requiring Revision Cervical Corpectomy.

Cervical disc arthroplasty is a well-established alternative to anterior cervical fusion but requires precise placement for optimal outcomes. We present the case of a 2-level cervical disc arthroplasty with suboptimal implantation of the interbody devices, requiring revision corpectomy. Supplemental video, Supplemental Digital Content 1 (http://links.lww.com/CLINSPINE/A358) content of the revision surgery is also provided. This report highlights the importance of proper implant sizing and position and reviews the nuances of surgical revision. A retrospective review of the clinical and radiographic data was performed from prior to the index operation through the 3-month postoperative period after the surgical revision. The patient presented approximately 2 years post-cervical arthroplasty with increasing neck pain and early cervical myelopathy. An imaging workup revealed severe cervical stenosis at the caudal level with cord compression and concern for device failure. Intraoperatively, the core of the caudal device was found to have ejected into the spinal canal. A cervical corpectomy of the intervening vertebra with the removal of both devices was performed. The patient had a complete neurologic recovery. Although failure of a cervical disc arthroplasty device is rare, the likelihood can be significantly increased with poor sizing (over or under sizing), asymmetric placement, endplate violation, or poor patient selection. In the case presented herein, early device failure was unrecognized, and the patient went on to develop progressive cervical myelopathy requiring revision corpectomy.

Comparing the Immune Response to PEEK as an Implant Material with and without P-15 Peptide as Bone Graft Material in a Rabbit Long Bone Model.

P-15 is a 15-amino-acid-long biomimetic peptide widely demonstrated to enhance osteogenesis in vivo. Despite the prevalence of polyether-ether-ketone (PEEK) in interbody device manufacturing, a growing body of evidence suggests it may produce an unfavorable immune response. The purpose of this preliminary study was to characterize the immune response and new bone growth surrounding PEEK implants with and without a P-15 peptide-based osteobiologic. A bilateral femoral defect model was conducted using New Zealand white rabbits. A total of 17 test subjects received one implant in each distal femur, either with or without bone graft material. Animals were allowed to survive to 4 or 8 weeks, at which time the femurs were collected and subjected to micro-computer tomography (microCT) or cytokine analysis. MicroCT analysis included the quantification of bone growth and density surrounding each implant. The cytokine analysis of periprosthetic tissue homogenates included the quantification of interleukins (ILs) and TNF-α expression via ELISA kits. Improvements in bone volume were observed in the P-15 cohort for the regions of interest, 500-136 and 136-0 µm from the implant surface, at 8 weeks post-op. Concentrations of IL-1β, IL-4, and IL-6 cytokines were significantly higher in the P-15 cohort compared to the PEEK cohort at the 4-week timepoint. Significant reductions in the concentrations of IL-4 and IL-6 cytokines from the 4- to 8-week cohort were observed in the P-15 cohort only. The P-15 peptide has the potential to modulate the immune response to implanted materials. We observed improvements in bone growth and a more active micro-environment in the P-15 cohort relative to the PEEK control. This may indicate an earlier transition from the inflammatory to remodeling phase of healing.

Radiographic Alignment in Deformity Patients Treated With Personalized Interbody Devices: Early Experience From the COMPASS Registry.

Literature supports the need for improved techniques to achieve spinopelvic alignment and reduce complication rates in patients with adult spinal deformity (ASD). Personalized interbody devices were developed to address this need and are under evaluation in the multicenter Clinical Outcome Measures in Personalized aprevo (circle R superscript) Spine Surgery (COMPASS (TM suprascript) registry. This report presents interim COMPASS pre- and postoperative sagittal alignment results and complication rates for a subcohort of COMPASS patients diagnosed and surgically treated for spinal deformity. COMPASS is a postmarket observational registry of patients enrolled either before or after index surgery and then followed prospectively for 24 months. Sagittal alignment was assessed with SRS-Schwab modifiers for pelvic incidence minus lumbar lordosis, pelvic tilt, and T1 pelvic angle. Summed SRS-Schwab modifiers were utilized to assign overall deformity status as mild, moderate, or severe. Complications were extracted from patient medical records. The study included 67 patients from 9 centers. Preoperative severe deformity was observed in 66% of patients. Index surgeries included implantation of a median of 2 personalized interbody devices by anterior, lateral, or transforaminal approaches and with a median of 8 posteriorly instrumented levels. Overall postoperative sagittal alignment improved with a significant decrease in the mean sum of SRS-Schwab modifiers that correlated strongly to improvements in pelvic incidence minus lumbar lordosis. Among 44 patients with preoperative severe overall deformity, 16 improved to moderate and 9 to mild deformity. Complications occurred for 13 patients (19.4%), including 1 mechanical complication requiring revision 9 months after surgery and none related to personalized interbody devices. This study demonstrates that ASD patients whose treatment included personalized interbody devices can obtain favorable postoperative alignment status comparable to published results and with no complications related to the personalized interbody devices. This study contributes to growing evidence that personalized interbody devices contribute to improved sagittal alignment in ASD patients by directly adjusting the orientation of adjacent vertebra.

Revision Surgery after Single Level Anterior Cervical Discectomy and Fusion With Plate vs Stand-Alone Cage over 2 to 5 Year Follow-Up.

retrospective study. To investigate the incidence of all-cause revision surgery between plated vs stand-alone cage constructs for single level ACDF. We retrospectively analyzed a commercial insurance claims database. Patients 18-65years-old were included if they underwent single-level inpatient ACDF (defined with CPT codes) from 2010 - 2018, with a minimum of 2-year continuous insurance enrollment. The primary independent variable was the use of anterior plating vs zero profile device or stand-alone cage. Synthetic (ie, metal, PEEK, etc.) vs allograft interbody was a secondary independent variable. The primary outcome variable was revision cervical arthrodesis after the index operation. In total, 21092 patients undergoing single-level inpatient ACDF were included. 10.0% received a stand-alone cage during the index operation. Mean follow-up duration was 4.5years. Revision arthrodesis occurred in 8.2% of patients overall, at a mean of 2.4years after the index surgery. Patients with anterior plating had a lower rate of all-cause revision surgery in unadjusted (overall rate 8.1% vs 9.6%, P = 0.0185) and adjusted analysis (OR 0.78, P = 0.0016) vs stand-alone cages. Patients with stand-alone cages had higher rates of revision with a posterior approach than did patients with plated constructs. In sub-analysis, the combination of a stand-alone interbody device with an allograft had significantly higher odds of revision than other combinations of devices. Among commercially insured patients ≤65years-old undergoing single-level ACDF, anterior plating was associated with a reduced incidence of revision surgery compared to stand-alone cages within the follow up period of our study.

Mismatch Between Pelvic Incidence and Lumbar Lordosis After Personalized Interbody Fusion: The Importance of Preoperative Planning and Alignment in Degenerative Spine Diseases.

Emerging data have highlighted the significance of planning and aligning total and segmental lumbar lordosis with pelvic morphology when performing short-segment fusion with the goal of reducing the risk of adjacent segment disease while also decreasing spine-related disability. This study evaluates the impact of personalized interbody implants in restoring pelvic incidence-lumbar lordosis (PI-LL) mismatch compared with a similar study using stock interbody implants. This multicenter retrospective analysis assessed radiographic pre- and postoperative spinopelvic alignment (PI-LL) in patients who underwent 1- or 2-level lumbar fusions with personalized interbody implants for degenerative (nondeformity) indications. The aim was to assess the incidence of malalignment (PI-LL ≥ 10°) both before and after fusion surgery and to determine the rate of alignment preservation and/or correction in this population. There were 135 patients included in this study. Of 83 patients who were aligned preoperatively, alignment was preserved in 76 (91.6%) and worsened in 7 (8.4%). Among the 52 preoperatively malaligned patients, alignment was restored in 23 (44.2%), and 29 (55.8%) were not fully corrected. Among patients who were preoperatively aligned, there was no statistically significant difference in either the "preserved" or "worsened" groups between stock devices and personalized interbody devices. In contrast, among patients who were preoperatively malaligned, there was a statistically significant increase in the "restored" group (P = 0.046) and a statistically significant decrease in the "worsened" groups in patients with personalized interbodies compared with historical stock device data (P < 0.05). Compared with a historical cohort with stock implants, personalized interbody implants in short-segment fusions have shown a statistically significant improvement in restoring patients to normative PI-LL. Using 3-dimensional preoperative planning combined with personalized implants provides an important tool for planning and achieving improvement in spinopelvic parameters.

Clinical performance of implanted devices used in surgical treatment of patients with spinal tumors: a systematic review

PurposeImplanted devices used in metastatic spine tumor surgery (MSTS) include pedicle screws, fixation plates, fixation rods, and interbody devices. A material to be used to fabricate any of these devices should possess an array of properties, which include biocompatibility, no toxicity, bioactivity, low wear rate, low to moderate incidence of artifacts during imaging, tensile strength and modulus that are comparable to those of cortical bone, high fatigue strength/long fatigue life, minimal or no negative impact on radiotherapy (RT) planning and delivery, and high capability for fusion to the contiguous bone. The shortcomings of Ti6Al4V alloy for these applications with respect to these desirable properties are well recognized, opening the field for an investigation about novel biomaterials that could replace the current gold standard. Previously published reviews on this topic have exhibited significant shortcomings in the studies they included, such as a small, heterogenous sample size and the lack of a cost-benefit analysis, extremely useful to understand the practical possibility of applying a novel material on a large scale. Therefore, this review aims to collect information about the clinical performance of these biomaterials from the most recent literature, with the objective of deliberating which could potentially be better than titanium in the future, with particular attention to safety, artifact production and radiotherapy planning interference. The significant promise showed by analyzing the clinical performance of these devices warrants further research through prospective studies with a larger sample size also taking into account each aspect of the production and use of such materials.MethodsThe Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were used to improve the reporting of the review. The search was performed from March 2022 to September 2023.ResultsAt the end of the screening process, 20 articles were considered eligible for this study. Polyetheretherketone (PEEK), Carbon-fibre reinforced polyetheretherketone (CFR-PEEK), long carbon fiber reinforced polymer (LCFRP), Polymethylmethacrylate (PMMA), and carbon screw and rods were used in the included studies.ConclusionCFR-PEEK displays a noninferior safety and efficacy profile to titanium implanted devices. However, it also has other advantages. By decreasing artifact production, it is able to increase detection of local tumor recurrence and decrease radiotherapy dose perturbation, ultimately bettering prognosis for patients necessitating adjuvant treatment. Nonetheless, its drawbacks have not been explored fully and still require further investigation in future studies. This does not exclude the fact that CFR-PEEK could be a valid alternative to titanium in the near future.

P137. Do interbody devices that traverse the lumbar apex result in improved outcomes and alignment in adult spinal deformity

P137. Do interbody devices that traverse the lumbar apex result in improved outcomes and alignment in adult spinal deformity

P145. Interbody device placement in thoracolumbar scoliosis malalignment affects mechanical complications and outcomes

P145. Interbody device placement in thoracolumbar scoliosis malalignment affects mechanical complications and outcomes

P264. Is manufacturer stated interbody device specifications an accurate predictor of postoperative segmental alignment and disc height?

P264. Is manufacturer stated interbody device specifications an accurate predictor of postoperative segmental alignment and disc height?

Outcomes and Spinopelvic Changes After Anterior Lumbar Interbody Fusion With a Novel Interbody Fusion Device: A Retrospective Study.

Interbody devices in anterior lumbar interbody fusion (ALIF) are currently a focus of innovation due to their potential to improve clinical outcomes. The purpose of the present study was to analyze complications and changes in spinopelvic parameters after ALIF with the novel Medacta MectaLIF interbody fusion device. Patients aged 18 to 80 years who underwent multilevel ALIF using this novel implant were identified. Demographic and surgical data were collected. Patients were divided into short- and long-fusion cohorts. A comparison of outcomes between the short- and long-fusion groups was performed using the Student t test for continuous variables and Fisher's exact test and the χ2 test for categorical variables. Analysis of the pre- vs postoperative radiographic data for the entire cohort was performed using the 2-tailed Student t test. One hundred and eight patients met the inclusion criteria. No significant postoperative change was observed in L1-4 lumbar lordosis (LL). L1-S1 LL increased to a mean of 55.1 ± 12.8 (a mean change of 10.7 ± 14.5), and L4-S1 LL increased to a mean of 38.4 ± 8.7 (a mean increase of 7.5 ± 8.2), with pelvic incidence LL mismatch changing from 8.9 ± 15.1 to 1.1 ± 13.5 (n = 102). Related changes in sacral slope and pelvic tilt were also observed (33.0 ± 11.0 to 37.6 ± 10.9 and 19.6 ± 9.5 to 18.2 ± 9.1 [n = 103], respectively). Five patients (4.6%) experienced implant subsidence, 1 (0.9%) had implant migration, and 6 (5.6%) experienced a nonunion. There was no difference in the rates of complications associated with the novel implant in the short- and long-fusion cohorts. This novel implant achieves correction of spinopelvic parameters with minimal complications. The ability to modify the implant intraoperatively based on the patient's anatomy can help achieve maximal contact area and therefore help reduce the risk of subsidence. This modular implant can achieve correction of spinopelvic parameters with minimal medical and surgical complications.

Biomechanical Behavior of Injected Cement Spacers versus Traditional Cages in Low-Density Lumbar Spine under Compression Loading.

Background and Objectives: Osteoporosis renders the use of traditional interbody cages potentially dangerous given the high risk of damage in the bone-implant interface. Instead, injected cement spacers can be applied as interbody devices; however, this technique has been mainly used in cervical spine surgery. This study aimed at investigating the biomechanical behavior of cement spacers versus traditional cages in lumbar spine surgery. Materials and Methods: Destructive monotonic axial compression testing was performed on 20 human cadaveric low-density lumbar segments from elderly donors (14 f/6 m, 70.3 ± 12.0 y) treated with either injected cement spacers (n = 10) or traditional cages (n = 10) without posterior instrumentation. Stiffness, failure load and displacement were compared. The effects of bone density, vertebral geometry and spacer contact area were evaluated. Results: Cement spacers demonstrated higher stiffness, significantly smaller displacement (p < 0.001) and a similar failure load compared to traditional cages. In the cage group, stiffness and failure load depended strongly on bone density and vertebral height, whereas failure displacement depended on vertebral anterior height. No such correlations were identified with cement spacers. Conclusions: Cement spacers used in lumbar interbody stabilization provided similar compression strength, significantly smaller failure displacement and a stiffer construct than traditional cages that provided benefits mainly for large and strong vertebrae. Cement stabilization was less sensitive to density and could be more beneficial also for segments with smaller and less dense vertebrae. In contrast to the injection of cement spacers, the optimal insertion of cages into the irregular intervertebral space is challenging and risks damaging bone. Further studies are required to corroborate these findings and the treatment selection thresholds.

Which interbody device minimized nonunion, subsidence, and reoperation after anterior cervical discectomy and fusion? A systematic review and meta-analysis comparing allograft versus polyetheretherketone cage.

Nonunion and significant subsidence after anterior cervical discectomy and fusion (ACDF) are associated with poor clinical outcomes, which occasionally lead to revision surgery. Allograft and polyetheretherketone (PEEK) cages are the two most commonly used interbody spacer devices for ACDF. Although studies have been conducted to compare the efficacies of these two interbody materials, the question remains regarding the superiority of one over the other. Therefore, the authors conducted a systematic review and meta-analysis to compare nonunion, subsidence, and reoperation rates after ACDF using allograft and PEEK cages as interbody devices. In this systematic review and meta-analysis, the authors systematically searched the MEDLINE, EMBASE, and Cochrane Library databases for studies published prior to November 2023 that compared the efficacy and safety of allograft and PEEK cages for ACDF. A pooled analysis was designed to identify differences in nonunion, subsidence, and reoperation rates between the two interbody devices. Ten studies involving 1462 patients (allograft, 852 patients; PEEK cage, 610 patients) were included. The pooled analysis demonstrated that allograft had a significantly lower rate of nonunion compared to that of PEEK cages (OR 0.33, 95% CI 0.14-0.79; p = 0.01). Furthermore, the reoperation rate due to nonunion was significantly higher with PEEK cages compared to that with allograft (OR 0.28, 95% CI 0.11-0.71; p < 0.01), whereas the reoperation rate due to overall causes did not display significant results (OR 0.38, 95% CI 0.11-1.29; p = 0.12). The incidence of significant subsidence (OR 0.66, 95% CI 0.28-1.55; p = 0.34) and the mean amount of subsidence (standard mean difference 0.03, 95% CI -0.42 to 0.47; p = 0.90) did not demonstrate significant differences between allograft and PEEK cages. Overall, the current meta-analysis suggests the advantages of allograft over PEEK cages used for ACDF, due to an enhanced fusion rate and minimized revision risk, with no increase in the risk of subsidence.

Retrospective analysis of medium-term outcomes following anterior lumbar interbody fusion surgery performed in a tertiary spinal surgical centre.

Anterior lumbar interbody fusion (ALIF) can treat spondylolisthesis, degenerative disc disease and pseudoarthrosis. This approach facilitates complete discectomy, disc space distraction, indirect decompression of neural foramina and placement of large interbody devices. Several intra- and postoperative complications can be attributed to the anterior approach: vascular/visceral injury, hypogastric plexus injury and urogenital consequences. Spine-specific complications include implant migration, graft failure, pseudoarthrosis and persistent symptomology. This retrospective study reviewed patient demographics, medium-term outcomes and complication rates following ALIF surgery performed over a 5-year period. A total of 110 consecutive patients had undergone ALIF surgery at a single tertiary spinal centre. The database was reviewed with a primary outcome of identifying postoperative 90-day complications and whether a revision anterior operation was required after primary ALIF. No patients required revision anterior operation after their primary ALIF surgery by final follow-up. Out of 110 patients, 11 (10%) recorded a complication attributed to the anterior stage of their operation within 90 days. Our 90-day complication rate of 10% lies within the 2.6% acute complication and 40% overall complications rates described in previous literature. The risk of vascular/visceral injury is significant (3%) and we recommend that ALIF be performed as a dual surgeon procedure with a vascular-trained access surgeon accompanying the spinal surgeon. ALIF is a valid revision surgical option for failed posterior approaches leading to complications such as pseudoarthrosis. In our sample, 89% of patients were managed with posterior fixation to augment the anterior fusion as, biomechanically, this is a proven construct.

Patients with Hip Osteoarthritis Have a Higher Rate of Spinal Reoperation Following Lumbar Spinal Fusion.

Lumbar spinal pathology is known to affect outcomes following total hip arthroplasty (THA). However, the effect of hip osteoarthritis (OA) on outcomes following lumbar fusion has not been well studied. The purpose of this study was to determine the association between hip OA and spinal reoperation following lumbar spinal fusion. The 5% Medicare Part B claims database was queried for all patients who underwent primary elective lumbar fusion from 2005 to 2019. Patients were divided into 2 groups: those who underwent elective THA within 1 year after primary lumbar fusion, indicating that they had severe hip OA at the time of lumbar fusion, and those who underwent lumbar fusion with no diagnosed hip OA and no THA during the study period. Exclusion criteria included THA as a result of trauma, revision THA or primary THA in the 5-year period before primary lumbar fusion, <65 years of age, and no enrollment in the database for 5 years before and 1 year after primary lumbar fusion. The primary outcome was spinal reoperation within 1, 3, and 5 years. Multivariable Cox regression was performed with age, sex, diabetes, heart disease, obesity, smoking status, osteoporosis, number of levels fused, use of posterior instrumentation, use of an interbody device, use of bone graft, and surgical approach as covariates. Overall, 1,123 patients (63.4% female; 91.3% White; mean age, 76.8 ± 4.1 years) were included in the hip OA group and 8,893 patients (56.2% female; 91.3% White; mean age, 74.8 ± 4.9 years) were included in the control group. After multivariable analysis, patients with severe hip OA had significantly greater rates of revision surgery at 3 years (odds ratio [OR], 1.61; p < 0.001) and 5 years (OR, 1.87; p < 0.001) after the index lumbar fusion. Patients with severe hip OA at the time of primary lumbar fusion had a significantly increased risk of spinal reoperation at 3 and 5 years postoperatively. These data provide further evidence to support performing THA prior to lumbar fusion in the unsettled debate regarding which surgery should be prioritized for patients with simultaneous degenerative diseases of the hip and lumbar spine. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Segmental Sagittal Alignment in Lumbar Spinal Fusion: A Review of Evidence-Based Evaluation of Preoperative Measurement, Surgical Planning, Intraoperative Execution, and Postoperative Evaluation.

Maintaining and restoring global and regional sagittal alignment is a well-established priority that improves patient outcomes in patients with adult spinal deformity. However, the benefit of restoring segmental (level-by-level) alignment in lumbar fusion for degenerative conditions is not widely agreed on. The purpose of this review was to summarize intraoperative techniques to achieve segmental fixation and the impact of segmental lordosis on patient-reported and surgical outcomes. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, PubMed, Embase, Cochrane, and Web of Science databases were queried for the literature reporting lumbar alignment for degenerative lumbar spinal pathology. Reports were assessed for data regarding the impact of intraoperative surgical factors on postoperative segmental sagittal alignment and patient-reported outcome measures. Included studies were further categorized into groups related to patient positioning, fusion and fixation, and interbody device (technique, material, angle, and augmentation). A total of 885 studies were screened, of which 43 met inclusion criteria examining segmental rather than regional or global alignment. Of these, 3 examined patient positioning, 8 examined fusion and fixation, 3 examined case parameters, 26 examined or compared different interbody fusion techniques, 5 examined postoperative patient-reported outcomes, and 3 examined the occurrence of adjacent segment disease. The data support a link between segmental alignment and patient positioning, surgical technique, and adjacent segment disease but have insufficient evidence to support a relationship with patient-reported outcomes, cage subsidence, or pseudoarthrosis. This review explores segmental correction's impact on short-segment lumbar fusion outcomes, finding the extent of correction to depend on patient positioning and choice of interbody cage. Notably, inadequate restoration of lumbar lordosis is associated with adjacent segment degeneration. Nevertheless, conclusive evidence linking segmental alignment to patient-reported outcomes, cage subsidence, or pseudoarthrosis remains limited, underscoring the need for future research.

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

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

466 Primary Anterior Lumbar Interbody Fusion, With and Without Posterior Instrumentation: A 1377 Patient Cohort From a Multicenter Spine Registry

INTRODUCTION: Anterior lumbar interbody fusion (ALIF) is a versatile and powerful technique for a variety of lumbar degenerative pathologies. Adding posterior supplementary fixation to ALIF (ALIF+PSF) is common and may confer benefits in terms of higher fusion rate but could contribute to adjacent segment disease (ASD) due to additional rigidity. METHODS: Adult patients who underwent primary ALIF for lumbar degenerative pathology between levels L4-S1 over a 12-year period were included. Cases of trauma, cancer, infection, supplemental decompression, noncontiguous fusions, prior lumbar fusions, and other interbody devices were excluded. Primary outcomes included reoperation for nonunion and ASD. Multivariable Cox proportional hazard regression was used to evaluate risks adjusting for patient characteristics. RESULTS: The study consisted of 1377 cases; 307 ALIF alone and 1070 ALIF+PSF. Mean follow-up time was 5.6-years. 5-year crude nonunion incidence was 2.4% for ALIF only and 0.5% for ALIF+PSF; after adjustment for covariates, a lower operative nonunion risk was observed for ALIF+PSF (HR = 0.22, 95% CI = 0.07-0.70). Of patients deemed potentially suitable for ALIF alone, one would need to add PSF in 53-patients to prevent one case of operative nonunion at a 5-year follow-up (number needed to treat). Five-year operative ASD incidence was 4.3% for ALIF only and 6.2% for ALIF+PSF; with adjustments, no difference was observed between the cohorts (HR = 0.96, 95% CI = 0.53-1.74). CONCLUSIONS: While addition of posterior instrumentation in ALIFs is associated with lower risk of operative nonunion compared to ALIF alone, it is rare in both techniques (&lt;5%). Accordingly, surgeons should evaluate added risks associated with addition of PSF, and rather reserve PSF for patients at higher risk for operative nonunion. Rates of operative ASD were not statistically higher with addition of PSF suggesting concern regarding future ASD may be less supported.

Single-Position Prone Lateral Lumbar Interbody Fusion Technique Guide: Surgical Tips and Tricks.

Lateral lumbar interbody fusion (LLIF) is a popular technique as it allows for the placement of a large interbody implant through a retroperitoneal, transpsoas working corridor. Historically, the interbody is placed with the patient in lateral decubitus and then repositioned to prone for the posterior instrumentation. While this has been an effective and successful technique, removing the interoperative flip would improve the efficiency of these cases. This has led to modified LLIF approaches including single-position prone LLIF (pLLIF). This modification has shown to be an efficient and powerful technique; however, learning to navigate the LLIF approach in the prone position has its own challenges. The purpose of this article is to provide a detailed description of our pLLIF technique while simultaneously introducing surgical tips to overcome the challenges of the approach and optimize the implantation of the interbody device.

Limited Intervention in Adult Scoliosis-A Systematic Review.

Adult scoliosis is traditionally treated with long-segment fusion, which provides strong radiographic correction and significant improvements in health-related quality of life but comes at a high morbidity cost. This systematic review seeks to examine the literature behind limited interventions in adult scoliosis patients and examine the best approaches to treatment. This is a MEDLINE- and PubMed-based literature search that ultimately included 49 articles with a total of 21,836 subjects. Our search found that long-segment interventions had strong radiographic corrections but also resulted in high perioperative morbidity. Limited interventions were best suited to patients with compensated deformity, with decompression best for neurologic symptoms and fusion needed to treat neurological symptoms secondary to up-down stenosis and to provide stability across unstable segments. Decompression can consist of discectomy, laminotomy, and/or foraminotomy, all of which are shown to provide symptomatic relief of neurologic pain. Short-segment fusion has been shown to provide improvements in patient outcomes, albeit with higher rates of adjacent segment disease and concerns for correctional loss. Interbody devices can provide decompression without posterior element manipulation. Future directions include short-segment fusion in uncompensated deformity and dynamic stabilization constructs. Limited interventions can provide symptomatic relief to adult spine deformity patients, with indications mostly in patients with balanced deformities and neurological pain.

Do Osteobiologics Augment Fusion in Anterior Cervical Discectomy and Fusion Surgery Performed With Mechanical Interbody Devices (Polyether ether ketone, Carbon Fiber, Metal Cages) and is the Fusion Rate Comparable to that With Autograft? A Systematic Review.

Systematic Review of the Literature. The purpose of this study was to perform a systematic review describing fusion rates for anterior cervical discectomy and fusion (ACDF) using autograft vs various interbody devices augmented with different osteobiologic materials. A systematic review limited to the English language was performed in Medline, Embase and Cochrane library using Medical Subject Heading (MeSH) terms. Studies that evaluated fusion after ACDF using autografts and osteobiologics combined with PEEK, carbon fibre, or metal cages were searched for. Articles in full text that met the criteria were included in the review. The main outcomes evaluated were the time taken to merge, the definition of the fusion assessment, and the modality of the fusion assessment. The risk of bias of each article was assessed by the MINORS score or ROB 2.0 depending on the randomisation process. The total number of references reviewed was six hundred and eighty-two. After applying the inclusion criteria, 54 were selected for the retrieval of the full text. Eight studies were selected and included for final analysis in this study. Fusion rates were reported between 83.3% and 100% for autograft groups compared to 46.5% and 100% for various interbody device/osteobiological combinations. The overall quality of the evidence in all radiographic fusion studies was considered insufficient due to a serious risk of bias. Mechanical interbody devices augmented with osteobiologics performed similarly to autografts in terms of reliability and efficacy. Their time to fusion and fusion rate were comparable to autografts at the end of the final follow-up.