Fusion rates based on type of bone graft substitute using minimally invasive scoliosis surgery for adolescent idiopathic scoliosis.

BACKGROUND: Minimally invasive scoliosis surgery (MISS) is currently introduced on novel technique for surgical treatment of adolescent idiopathic scoliosis (AIS). This study is aimed to evaluate the efficacy of facet fusion in MISS compared to posterior fusion in conventional open scoliosis surgery (COSS) and compare facet fusion rates based on three bone graft substitutes in MISS for adolescent idiopathic scoliosis (AIS). METHODS: Eighty six AIS patients who underwent scoliosis surgery were divided into two groups: the COSS group and the MISS group. COSS was performed through posterior fusion with allograft. MISS was applied via facet fusion with three bone graft substitutes. The MISS group was further divided into three subgroups based on graft substitute: Group A (allograft), Group B (demineralized bone matrix [DBM]), and group C (demineralized cancellous bone chips). Fusion rate was measured using conventional radiographs to visualize loss of correction > 10°, presence of lysis around implants, breaks in fusion mass, and abnormal mobility of the fused segment. RESULTS: The fusion rates showed no significant difference in COSS and MISS groups (p = 0.070). In the MISS group, the fusion rates were 85, 100, and 100% in groups A, B, and C, respectively, with no significant difference (p = 0.221). There were no statistical differences between groups A, B, and C in terms of correction rate, fusion rate, and SRS-22 scores (p > 0.05). CONCLUSIONS: The facet fusion in MISS showed comparable to posterior fusion in COSS with regard to radiological and clinical outcomes. Furthermore, the type of graft substitute among allograft, DBM, and demineralized cancellous bone chips did not affect facet fusion rate or clinical outcomes in MISS. Therefore, MISS showed comparable fusion rate (with no influences on the type of graft substitute) and clinical outcomes to those of COSS in the surgical treatment of AIS.

Improvement following minimally invasive transforaminal lumbar interbody fusion in patients aged 70 years or older compared with younger age groups.

OBJECTIVE: The goal of this study was to assess the outcomes of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) in patients ≥ 70 years old and compare them to younger age groups. METHODS: This was a retrospective study of data that were collected prospectively. Patients who underwent primary single-level MI-TLIF were included and divided into 3 groups: age < 60, 60-69, and ≥ 70 years. The outcome measures were as follows: 1) patient-reported outcome measures (PROMs) (i.e., visual analog scale [VAS] for back and leg pain, Oswestry Disability Index [ODI], 12-Item Short-Form Health Survey Physical Component Summary [SF-12 PCS]); 2) minimum clinically important difference (MCID) achievement; 3) return to activities; 4) opioid discontinuation; 5) fusion rates; and 6) complications/reoperations. RESULTS: A total of 147 patients (age < 60 years, 62; 60-69 years, 47; ≥ 70 years, 38) were included. All the groups showed significant improvements in all PROMs at the early (< 6 months) and late (≥ 6 months) time points and there was no significant difference between the groups. Although MCID achievement rates for VAS leg and ODI were similar, they were lower in the ≥ 70-year-old patient group for VAS back and SF-12 PCS. Although the time to MCID achievement for ODI and SF-12 PCS was similar, it was greater in the ≥ 70-year-old patient group for VAS back and leg. There was no significant difference between the groups in terms of return to activities, opioid discontinuation, fusion rates, and complication/reoperation rates. CONCLUSIONS: Although patients > 70 years of age may be less likely and/or take longer to achieve MCID compared to their younger counterparts, they show an overall significant improvement in PROMs, a similar likelihood of returning to activities and discontinuing opioids, and comparable fusion and complication/reoperation rates following MI-TLIF.

Lateral lumbar interbody fusion - clinical outcomes, fusion rates and complications with recombinant human bone morphogenetic protein-2.

BACKGROUND: The authors report an Australian experience of lateral lumbar interbody fusion (LLIF) with respect to clinical outcomes, fusion rates, and complications, with recombinant human bone morphogenetic protein-2 (rhBMP-2) and other graft materials. METHODS: Retrospective cohort study of LLIF patients 2011-2021. LLIFs performed lateral decubitus by four experienced surgeons past their learning curve. Graft materials classified rhBMP-2 or non-rhBMP-2. Patient-reported outcomes assessed by VAS, ODI, and SF-12 preoperatively and postoperatively. Fusion rates assessed by CT postoperatively at 6 and 12 months. Complications classified minor or major. Clinical outcomes and complications analysed and compared between rhBMP-2 and non-rhBMP-2 groups. RESULTS: A cohort of 343 patients underwent 437 levels of LLIF. Mean age 67 ± 11 years (range 29-89) with a female preponderance (65%). Mean BMI 29kg/m2 (18-56). Most common operated levels L3/4 (36%) and L4/5 (35%). VAS, ODI and SF-12 improved significantly from baseline. Total complication rate 15% (53/343) with minor 11% (39/343) and major 4% (14/343). Ten patients returned to OR (2-wound infection, 8-further instrumentation and decompression). Most patients (264, 77%) received rhBMP-2, the remainder a non-rhBMP-2 graft material. No significant differences between groups at baseline. No increase in minor or major complications in the rhBMP-2 group compared to the non-rhBMP-2 group respectively; (10.6% vs 13.9% [p = 0.42], 2.7% vs 8.9% [p < 0.01]). Fusion rates significantly higher in the rhBMP-2 group at 6 and 12 months (63% vs 40%, [p < 0.01], 92% vs 80%, [p < 0.02]). CONCLUSION: LLIF is a safe and efficacious procedure. rhBMP-2 in LLIF produced earlier and higher fusion rates compared to available non-rhBMP-2 graft substitutes.

Clinical and biomechanical researches of polyetheretherketone (PEEK) rods for semi-rigid lumbar fusion: a systematic review.

Lumbar spinal fusion using rigid rods is a common surgical technique. However, adjacent segment disease and other adverse effects can occur. Dynamic stabilization devices preserve physiologic motion and reduce painful stress but have a high rate of construct failure and reoperation. Polyetheretherketone (PEEK) rods for semi-rigid fusions have a similar stiffness and adequate stabilization power compared with titanium rods, but with improved load sharing and reduced mechanical failure. The purpose of this paper is to review and evaluate the clinical and biomechanical performance of PEEK rods. A systematic review of clinical and biomechanical studies was conducted. A literature search using the PubMed, EMBASE, and Cochrane Library databases identified studies that met the eligibility criteria. Eight clinical studies and 15 biomechanical studies were included in this systematic review. The visual analog scale and the Oswestry disability index improved significantly in most studies, with satisfactory fusion rates. The occurrence of adjacent segment disease was low. In biomechanical studies, PEEK rods demonstrated a superior load-sharing distribution, a larger adjacent segment range of motion, and reduced stress at the rod-screw/screw-bone interfaces compared with titanium rods. The PEEK rod construct was simple to assemble and had a reliable in vivo performance compared with dynamic devices. The quality of clinical studies was low with confounding results, although results from mechanical studies were encouraging. There is no evidence strong enough to confirm better outcomes with PEEK rods than titanium rods. More studies with better protocols, a larger sample size, and a longer follow-up time are needed.

Feasibility and outcome of stand-alone trans-articular screw fixation in atlantoaxial instability in children less than 8 years of age.

PURPOSE: To study the feasibility and outcome of stand-alone trans-articular screw (TAS) fixation for atlantoaxial instability (AAI) in children less than 8 years of age. METHODS: This prospective study was conducted between 2009 and 2014. Thirteen children suffering from AAI were operated for a TAS fixation. Feasibility of TAS fixation was assessed on CT scan and a screw diameter was chosen based on C2 isthmus diameter. Demographic data collected included the etiology for AAI, age, and sex. Intra-operative data recorded was the duration of surgery, blood loss, vertebral artery injury or any adverse event. Radiological evaluation included pre- and post-operative atlantodens interval (ADI) and space available for cord (SAC) and fusion was evaluated at 3, 6, 12 and 24 months. Statistical analysis was done using SPSS software and statistical significance was set at p < 0.05. RESULTS: The mean age of the final study group was 6.1 ± 1.5 years, with nine males and four females. Mean isthmus diameter on the left and right side was 3.3 ± 0.3 and 3.2 ± 0.2 mm, respectively. Five patients had an isthmus diameter of < 3.2 mm and a 2.7 mm Herbert screw was used in them and in nine patients, a CCS of 3.2 mm was used. Mean pre- and post-op ADI and SAC improved from 5.5 ± 0.8 to 3.1 ± 0.1 mm, respectively, and 9.8 ± 2.8 to 14 ± 0.6 mm, respectively. Fusion was seen in all patients. CONCLUSIONS: Stand-alone TAS with morselized allograft is safe, feasible and successful in managing AAI in children below 8 years of age. These slides can be retrieved under Electronic Supplementary Material.

The Utility of Postoperative Bracing on Radiographic and Clinical Outcomes Following Cervical Spine Surgery: A Systematic Review.

STUDY DESIGN: Systematic Review. OBJECTIVES: To determine the radiographic and clinical utility of postoperative orthoses following cervical spine surgery. METHODS: We performed a search of the PubMed, Cochrane Library, Medline Ovid, and SCOPUS databases from inception until November 2021. Eligible studies included outcomes of postoperative bracing vs no bracing following cervical spine surgery. The primary outcome of interest was fusion rates after cervical surgery in braced vs unbraced patients. Secondary outcomes included patient reported outcomes and complication rates. RESULTS: A total of 3232 titles were initially screened. After inclusion criteria were applied, 7 studies (550 patients) were included, which compared results of braced vs unbraced patients after cervical spine surgery. These studies showed acceptable reliability for inclusion based on the Methodical Index for Non-Randomized studies and Critical Appraisal Skills Programme assessment tools. There were no significant differences in fusion rates or complications between braced vs unbraced patients identified in any study. Patient reported pain and quality of life measures between braced and unbraced groups varied amongst studies, without any clear overall advantages favoring either method. CONCLUSIONS: This systematic review found that external bracing, though widely used following cervical spine surgery, may not offer any advantages in patient-reported outcomes, as compared to not bracing. In regard to the effect of bracing on fusion rates, no strong consensus can be made as the methods of fusion assessment in the included studies were heterogenous and suboptimal. Future high-quality studies using recommended methods of fusion assessment are needed to adequately address this important question.

Do Diabetic Patients Have Poorer Clinical and Radiological Outcomes Following Minimally Invasive Transforaminal Lumbar Interbody Fusion?

BACKGROUND: The number of patients with diabetes mellitus (DM) seeking treatment for degenerative spondylolisthesis is expected to increase. However, there is a paucity of studies examining the patient-reported outcomes (PROs) and subjective measures in patients with DM following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). The present study aimed to compare PROs, satisfaction, and radiological fusion between DM and non-DM patients following MIS-TLIF. METHODS: The authors identified 30 patients with DM who underwent primary, single-level MIS-TLIF for degenerative spondylolisthesis from a spine registry. Each patient was matched 1:1 with 30 controls without DM using propensity scores to adjust for age, sex, body mass index, American Society of Anesthesiologists class, and baseline PROs. Visual analog scale leg pain, back pain, Oswestry Disability Index (ODI), SF-36 physical component score and mental component scores were compared at 1, 3, 6, and 24 months. Patients also completed a satisfaction questionnaire during these visits. Radiographic fusion was analyzed according to Bridwell grades. RESULTS: There was no difference in PROs between non-DM and DM patients at 2 years. However, a higher proportion of non-DM patients attained minimal clinically important difference for ODI (90.0% vs 66.7% P = 0.028) and SF-36 physical component score (90.0% vs 53.3% P = 0.002) at 3 months and ODI (96.7% vs 80.0%) at 6 months. A similar proportion of patients in each group were satisfied and had expectations fulfilled. A higher proportion of non-DM patients attained a grade 1 or 2 fusion (93.3%), as compared with DM patients (80.0%), although this did not reach statistical significance (P = 0.129). CONCLUSIONS: DM patients have poorer initial PROs, which reach comparable levels to those in non-DM patients in the longer-term. Fusion rates of DM patients were poorer compared with non-DM patients.

The Effect of Plate Thickness on Fusion, Complications, and Outcomes in Anterior Cervical Spine Surgery.

Background and objective Anterior cervical discectomy and fusion (ACDF) is a common surgery involving the cervical spine. The goals of ACDF include obtaining a solid fusion and minimizing complications such as dysphagia. The effect of plate thickness on fusion, dysphagia, and patient outcomes is not well established. In light of this, this study aimed to evaluate the effect of plate thickness on fusion rates, complications, and outcomes in ACDF. Methods A case-control study involving ACDF performed by a single surgeon was conducted with the aim of comparing two commercially available plating systems: the Medtronic plate (Atlantis Vision Elite, Medtronic, Memphis, TN) and Aegis plate (CastleLoc-P, Aegis, Englewood, CO). The patients treated with the Medtronic plate served as the control group (Std) as the plate is widely utilized, while those treated with the Aegis plate, which is touted as one of the thinnest plates on the market, constituted the case low-profile group (LP). Demographic variables, fusion status, and patient-reported outcome measures (PROM) were compared between the two systems. Results Baseline demographic data were not significantly different between groups. The LP plate group had a significantly lower rate of fusion per patient as well as per level at 12 months. PROM did not significantly differ at any time point between the groups. Dysphagia scores could be correlated with radiographic measures reported in the Prevertebral Soft Tissue Swelling - Index (PVSTS-I).  Conclusion Based on our findings, the plate thickness was not associated with dysphagia rates; however, the use of a thinner plate correlated with a lower rate of radiographic fusion at 12 months. The PVSTS-I may be useful for identifying patients with abnormal and severely abnormal dysphagia scores.

Sacroiliac Joint Fusion: Fusion Rates and Clinical Improvement Using Minimally Invasive Approach and Intraoperative Navigation and Robotic Guidance.

STUDY DESIGN: This study adopted a retrospective study design. PURPOSE: This study was designed to describe the fusion rate and technique and patient subjective improvement after sacroiliac (SI) joint fusion using a minimally invasive surgical (MIS) approach. OVERVIEW OF LITERATURE: The SI joint can mimic radicular or discogenic pain localized to the lower back, gluteal region, or sacral region, posing a challenge in the diagnosis and treatment. This study determines the radiological fusion rate and patient reported subjective clinical outcomes of SI joint fusion using an MIS approach, comparing the use of the Rialto SI joint fusion system (Medtronic, Minneapolis, MN, USA) with the help of the Stealth Navigation System with the use of ExcelsiusGPS Robotic Navigation Platform (Globus Medical Inc., Audubon, PA, USA) using SI-LOK screws (Globus Medical Inc.). METHODS: In this retrospective study, 43 consecutive patients who underwent SI joint fusion between August 2017 and February 2020 were enrolled; 60 SI joints were fused. The patients' fusion was documented on computed tomography or X-rays, and Visual Analog Scale (VAS) scores were used to determine patient subjective clinical outcomes. RESULTS: A total of 60 joints were fused, including 26 joints fused using robotic guidance and 34 joints fused using the Stealth Navigation System. Student t-test was used to compare the mean preoperative VAS score (7.52±1.3) with the mean postoperative VAS score at the 12-month follow-up (1.43±1.22) (p<0.05). The SI joint fusion rate using this technique was 61% at 6 months, 96.4% at 12 months, and 100% at 18 months. CONCLUSIONS: The use of navigation guidance or robotic assistance enables accurate percutaneous screw placement across the SI joint. The use of bone morphogenetic protein in the screw bore hastens fusion across the joint, improving patient-perceived pain.

Review of anterior cervical diskectomy/fusion (ACDF) using different polyetheretherketone (PEEK) cages.

Background: Multiple anterior cervical diskectomy/fusion (ACDF) techniques now use a variety of Polyehteretherketone (PEEK) cages; stand-alone (SA) and zero-profile (ZP) with/without screws, cages filled with demineralized bone matrix/autograft, and cages coated with hydroxyapatite or titanium. We compared the safety/ efficacy between different PEEK ACDF cage constructs in 17 studies, and in some cases, additionally contrasted results with "routine" ACDF (i.e. series/historical data performed with combinations of iliac autograft/allograft and plates). Methods: We focused on the clinical outcomes, fusion rates, postoperative radiographic changes/lordosis/ subsidence, and/or reoperation rates for various PEEK ACDF constructs vs. "routine" ACDF. Results: One to 3 and 4-level PEEK ACDF cages demonstrated high fusion rates, few cage failures, and low reoperation rates. Subsidence for PEEK ACDF cages did not reduce fusion rates or diminish the quality of postoperative outcomes. Further, titanium-coated (T-C) PEEK cages lowered fusion rates in one study (i.e. 44.1% fusions vs. 88.2% for routine PEEK ACDF) while ACDF PEEK cages coated with hydroxyapatite (HA) showed only a "trend" toward enhanced arthrodesis. Conclusion: One to 3-4 multilevel ACDF PEEK cage constructs demonstrated comparable safety/efficacy when compared with each other, or in select cases, with "routine" ACDF (i.e. using autograft/allograft and plates).

Comparing Fusion Rates Between Fresh-Frozen and Freeze-Dried Allografts in Anterior Cervical Discectomy and Fusion.

Objective: The objective of this retrospective study is to compare the fusion rates in anterior cervical discectomy and fusion surgery using freeze-dried versus fresh-frozen allografts. Methods: The study comprised 79 patients. Fifty-one patients received freeze-dried allograft (106 total spinal levels) and 28 patients received fresh-frozen allograft (50 total spinal levels). Fusion was assessed through trabecular bridging on follow-up anterior-posterior/lateral radiographs. Trabecular bridging was assessed on the superior and inferior borders of each spinal level and given a fusion grade. Complete fusion is defined as >50% bridging between superior and inferior borders of the bone graft; union is complete fusion in <26 weeks; delayed union is complete fusion after 26 weeks; and fibrous union is <50% bridging at ≥1 borders over 52 weeks. Results: All spinal levels reached complete fusion for both graft types. Of the freeze-dried treated cervical spinal levels, 77.35% (82/106) reached union (adequate trabecular bridging within 6 months) without delay compared with 80% (35/50) for the fresh-frozen bone graft group (P = 0.85). There was no significant difference in time-to-fusion analysis and no significant association between delayed union and any patient factors. In assessing Neck Disability Index (NDI), freeze-dried allografts did show a significantly greater decrease in NDI scores at 6 months (P = 0.03). At the 1 year follow-up, improvements in NDI were consistent in both allografts (P = 0.9647). Conclusions: From this study, freeze-dried and fresh-frozen allografts showed comparable rates of union, and both allografts can be used interchangeably for anterior cervical discectomy and fusion.

Is there a difference in the outcomes of anterior cervical discectomy and fusion among female patients with different menopausal statuses?

BACKGROUND: The surgical outcomes of anterior cervical discectomy and fusion (ACDF) in female patients according to menopausal status remain unclear. The objective of this study was to investigate the differences in these outcomes among female patients with different menopausal statuses. METHODS: Ninety-one patients undergoing single-level or consecutive two-level ACDF with a minimum 12-month postoperative follow-up were included in this study. There were 38 patients in the premenopausal group, 28 patients in the early postmenopausal group, and 25 patients in the late postmenopausal group. The clinical outcomes were evaluated by means of the neck disability index (NDI) scores, Japanese Orthopedic Association (JOA) scores, and visual analog scale (VAS) scores. Radiological parameters included cervical lordosis (CL), the functional spinal unit (FSU) angle, range of motion (ROM) of the total cervical spine, ROM of the FSU, anterior and posterior FSU height, implant subsidence, adjacent segment degeneration (ASD), and Hounsfield unit (HU) values. RESULTS: All groups showed significant improvements in their JOA, VAS, and NDI scores (P < 0.05). The differences in preoperative and final follow-up CL, ROM of C2-7, FSU angle, and ROM of FSU were not statistically significant among the three groups (P > 0.05). The anterior FSU height loss rate showed a significant difference (P = 0.043), while there was no difference in the posterior FSU height loss rate (P = 0.072). The fusion rates in the early and late postmenopausal groups were consistently lower than those in the premenopausal group during the follow-up period. All patients had satisfactory outcomes at the final follow-up. CONCLUSION: There were no significant differences in clinical or other related outcomes of single-level or consecutive two-level ACDF in the long term among female patients with different menopausal statuses. However, the early bony fusion rates and anterior FSU height loss rates were poorer in late postmenopausal patients than in premenopausal or early postmenopausal patients. Hence, importance should be attached to the protection of late postmenopausal patients in the early postoperative period to guarantee solid bony fusion.

Fusion Rates of Lateral Lumbar Interbody Fusion Using Recombinant Human Bone Morphogenetic Protein-2.

STUDY DESIGN: Retrospective observational case series. OBJECTIVES: Lateral lumbar interbody fusion (LLIF) has been widely performed with recombinant human bone morphogenetic protein-2 (rhBMP-2), but the fusion rates using this graft alternative have not been well studied. We aimed to evaluate fusion rates in 1- and 2-level LLIF with rhBMP-2 and their relationship with fixation, as well as rates of BMP-related complications. METHODS: Institutional review board (IRB)-approved spine registry cohort of 93 patients who underwent LLIF with rhBMP-2 (71 one-level cases and 22 two-level cases). Minimum 1-year clinical follow-up and computed tomography (CT) scan for fusion assessment. Postoperative CT scans were used to evaluate the rate of fusion in all patients. Instrumentation and complications were collected from chart and imaging review. RESULTS: Average age was 65 years (67% female). For 1-level cases, 92% (65/71) had complete fusion and 8% (6/71) had either incomplete or indeterminate fusion. Three of the 6 patients who had incomplete or indeterminate fusion had bilateral pedicle screw instrumentation, 1 patient had unilateral posterior fixation, and 2 had no fixation. In 2-level cases, 86% (19/22) had complete fusion and 14% (3/22) had either incomplete or indeterminate fusion. The 3 patients who had incomplete or indeterminate fusion did not have fixation. CONCLUSION: Interbody fusion rates with rhBMP-2 via LLIF was 92% in 1-level cases and 86% in 2-level cases, indicating that rhBMP-2 may be used as a viable graft alternative to allograft options for LLIF. Higher rates of pseudarthrosis occurred when not using fixation.

Clinical and radiologic outcomes of single-level direct lateral lumbar interbody fusion in patients with osteopenia.

OBJECTIVE: Subsidence of the interbody graft into the vertebral bodies is one of the major complications of direct lateral interbody fusion (DLIF), resulting in pseudoarthrosis and severe pain. Low bone mineral density (BMD) has been known to increase the risk of subsidence. This study aims to determine whether or not the osteopenia should influence the surgical results in DLIF surgery. METHODS: We retrospectively reviewed the data collected prospectively on all patients who underwent single-level DLIF at our institution. A total of 84 patients were included in this study, comprised of 41 in the osteopenia group and 43 in the normal BMD group. The clinical and radiologic characteristics were compared at preoperative and postoperative 1 and 2 years. RESULTS: At postoperative two years, there was a statistically significant difference in disc height and intervertebral foramen height at index level between the two groups (p = 0.039, 0.044, respectively), but there was no significant difference in total lumbar lordosis (p = 0.179). At 24-month postoperative, 92.7% of the osteopenia group and 95.3% of the normal BMD group were solidly fused (p = 0.672). All postoperative clinical scores (VAS back pain, VAS leg pain, and ODI) improved similarly in both groups without significant difference. The overall incidence of cage subsidence with >3 mm was 17.1% in the osteopenia group and 9.3% in the normal BMD group (p = 0.345). CONCLUSIONS: Patients with osteopenia who undergo single-level DLIF combined with posterior fixation exhibited comparable clinical and radiological outcomes as patients with normal BMD.

Minimally Invasive Lumbar Pedicle Screw Fixation Using Cortical Bone Trajectory: Functional Outcomes.

Background Pedicle screw fixation is currently the mainstay technique for lumbar spinal fusion; however, more minimally invasive techniques are available such as cortical screw fixation. Numerous studies have proven biomechanical equivalence or superiority for cortical screws but few studies have examined clinical outcomes in patients. Our study aims to examine functional outcomes, as well as fusion rates, in patients who underwent pedicle screw fixation using a cortical trajectory. Methods We retrospectively reviewed prospectively collected functional outcomes data on 10 patients with a degenerative lumbar disease who underwent cortical screw placement by the senior author. Oswestry Disability Index (ODI) and Roland Morris (RM) scoring were calculated preoperatively, at six to 12 weeks and at six to eight months. The Kruskal-Wallis test and Dunn's multiple comparison were used to analyze differences in scores over time. Results We found that over time, cortical screw fixation resulted in a mean decrease of 27 from the baseline ODI at six to eight months (p = 0.014). Additionally, six out of seven (86%) patients who had at least 12 months of radiographic follow-up showed fusion. Conclusions Cortical screw fixation showed a decrease of 27 from the baseline ODI at six to eight months, which is comparable to changes from the baseline ODI reported in three, recent, large clinical trials examining functional outcomes following traditional pedicle screw fixation.

High posterior cervical fusion rates with iliac autograft and Nanoss/bone marrow aspirate.

BACKGROUND: Patients with severe cervical multilevel stenosis and an adequate lordotic curvature often undergo multilevel laminectomies with posterior instrumented fusions. Although the "gold standard" for the fusion mass remains iliac crest autograft, many require additional volume provided by bone graft expanders. Here, we studied the fusion rates for 32 patients undergoing multilevel cervical laminectomy and vertex/rod/eyelet/titanium cable fusions utilizing lamina/iliac autograft and the bone graft expander Nanoss (RTI Surgical, Alachua, FL, USA) with autogenous bone marrow aspirate (BMA). METHODS: Thirty-two patients, averaging 63.0 years of age, presented with severe cervical myeloradiculopathy (average Nurick Grade 4.4). Magnetic resonance (MR) studies documented 2-3-level high intrinsic cord signals, whereas computed tomography (CT) scans confirmed marked stenosis and ossification of the posterior longitudinal ligament (OPLL)/ossification of the yellow ligament (OYL). Patients underwent multilevel lamnectomies/instrumented fusions, and were followed up for an average of 2.7 years. RESULTS: Multilevel laminectomies (2.8 levels) and average 7.8-level vertex/rod/eyelet/cable fusions were performed utilizing lamina/iliac crest autograft and Nanoss/BMA. Fusion was confirmed on X-ray/CT studies an average of 4.7 months postoperatively in 31 of 32 patients (97%); there was just one pseudarthrosis requiring secondary surgery. The only other complication was a delayed transient C5 palsy that fully resolved in 6 postoperative months. CONCLUSIONS: Thirty-two severely myelopathic underwent 2.8-level cervical laminectomies/7.8 level fusions utilizing lamina/iliac autograft and Nanoss/BMA. Fusion was documented on both dynamic X-ray and CT studies in 31 of 32 (97%) patients an average of 4.7 months postoperatively. Nanoss/BMA appears to be a safe and effective bone graft expander that can be utilized for posterior cervical fusions.

Technical description of oblique lateral interbody fusion at L1-L5 (OLIF25) and at L5-S1 (OLIF51) and evaluation of complication and fusion rates.

BACKGROUND CONTEXT: The oblique lateral interbody fusion (OLIF) procedure is aimed at mitigating some of the challenges seen with traditional anterior lumbar interbody fusion (ALIF) and transpsoas lateral lumbar interbody fusion (LLIF), and allows for interbody fusion at L1-S1. PURPOSE: The study aimed to describe the OLIF technique and assess the complication and fusion rates. STUDY DESIGN: This is a retrospective cohort study. PATIENT SAMPLE: The sample is composed of 137 patients who underwent OLIF procedure. OUTCOME MEASURES: The outcome measures were adverse events within 6 months of surgery: infection, symptomatic pseudarthrosis, hardware failure, vascular injury, perioperative blood transfusion, ureteral injury, bowel injury, renal injury, prolonged postoperative ileus (more than 3 days), incisional hernia, pseudohernia, reoperation, neurologic deficits (weakness, numbness, paresthesia), hip flexion pain, retrograde ejaculation, sympathectomy affecting lower extremities, deep vein thrombosis, pulmonary embolism, myocardial infarction, pneumonia, and cerebrovascular accident. The outcome measures also include fusion and subsidence rates based on computed tomography (CT) done at 6 months postoperatively. METHODS: Retrospective chart review of 150 consecutive patients was performed to examine the complications associated with OLIF at L1-L5 (OLIF25), OLIF at L5-S1 (OLIF51), and OLIF at L1-L5 combined with OLIF at L5-S1 (OLIF25+OLIF51). Only patients who had at least 6 months of postoperative follow-up, including CT scan at 6 months after surgery, were included. Independent radiology review of CT data was performed to assess fusion and subsidence rates at 6 months. RESULTS: A total of 137 patients underwent fusion at 340 levels. An overall complication rate of 11.7% was seen. The most common complications were subsidence (4.4%), postoperative ileus (2.9%), and vascular injury (2.9%). Ileus and vascular injuries were only seen in cases including OLIF51. No patient suffered neurologic injury. No cases of ureteral injury, sympathectomy affecting the lower extremities, or visceral injury were seen. Successful fusion was seen at 97.9% of surgical levels. CONCLUSIONS: Oblique lateral interbody fusion is a safe procedure at L1-L5 as well as L5-S1. The complication profile appears acceptable when compared with LLIF and ALIF. The oblique trajectory mitigates psoas muscle and lumbosacral plexus-related complications seen with the lateral transpsoas approach. Furthermore, there is a high fusion rate based on CT data at 6 months.

Do Trunk Muscles Affect the Lumbar Interbody Fusion Rate?: Correlation of Trunk Muscle Cross Sectional Area and Fusion Rates after Posterior Lumbar Interbody Fusion Using Stand-Alone Cage.

OBJECTIVE: Although trunk muscles in the lumbar spine preserve spinal stability and motility, little is known about the relationship between trunk muscles and spinal fusion rate. The aim of the present study is to evaluate the correlation between trunk muscles cross sectional area (MCSA) and fusion rate after posterior lumbar interbody fusion (PLIF) using stand-alone cages. METHODS: A total of 89 adult patients with degenerative lumbar disease who were performed PLIF using stand-alone cages at L4-5 were included in this study. The cross-sectional area of the psoas major (PS), erector spinae (ES), and multifidus (MF) muscles were quantitatively evaluated by preoperative lumbar magnetic resonance imaging at the L3-4, L4-5, and L5-S1 segments, and bone union was evaluated by dynamic lumbar X-rays. RESULTS: Of the 89 patients, 68 had bone union and 21 did not. The MCSAs at all segments in both groups were significantly different (p<0.05) for the PS muscle, those at L3-4 and L4-5 segments between groups were significantly different (p=0.048, 0.021) for the ES and MF muscles. In the multivariate analysis, differences in the PS MCSA at the L4-5 and L5-S1 segments remained significant (p=0.048, 0.043 and odds ratio=1.098, 1.169). In comparison analysis between male and female patients, most MCSAs of male patients were larger than female's. Fusion rates of male patients (80.7%) were higher than female's (68.8%), too. CONCLUSION: For PLIF surgery, PS muscle function appears to be an important factor for bone union and preventing back muscle injury is essential for better fusion rate.

Systematic review and meta-analysis of minimally invasive transforaminal lumbar interbody fusion rates performed without posterolateral fusion.

The need for posterolateral fusion (PLF) in addition to interbody fusion during minimally invasive (MIS) transforaminal lumbar interbody fusion (TLIF) has yet to be established. Omitting a PLF significantly reduces overall surface area available for achieving a solid arthrodesis, however it decreases the soft tissue dissection and costs of additional bone graft. The authors sought to perform a meta-analysis to establish the fusion rate of MIS TLIF performed without attempting a PLF. We performed an extensive Medline and Ovid database search through December 2010 revealing 39 articles. Inclusion criteria necessitated that a one or two level TLIF procedure was performed through a paramedian MIS approach with bilateral posterior pedicle screw instrumentation and without posterolateral bone grafting. CT scan verified fusion rates were mandatory for inclusion. Seven studies (case series and case-controls) met inclusion criteria with a total of 408 patients who underwent MIS TLIF as described above. The mean age was 50.7 years and 56.6% of patients were female. A total of 78.9% of patients underwent single level TLIF. Average radiographic follow-up was 15.6 months. All patients had local autologous interbody bone grafting harvested from the pars interarticularis and facet joint of the approach side. Either polyetheretherketone (PEEK) or allograft interbody cages were used in all patients. Overall fusion rate, confirmed by bridging trabecular interbody bone on CT scan, was 94.7%. This meta-analysis suggests that MIS TLIF performed with interbody bone grafting alone has similar fusion rates to MIS or open TLIF performed with interbody supplemented with posterolateral bone grafting and fusion.

Plasmapore-coated titanium cervical cages induce more rapid and complete bone fusion after anterior cervical discectomy and fusion as compared to noncoated titanium cages.

OBJECTIVE: The aim of this study was to examine the solid bone fusion rates between Plasmapore-coated titanium cages (PPC group) and non-Plasmapore-coated titanium cages (N-PPC group) in patients who received anterior cervical decompression and fusion (ACDF). METHODS: Of 78 patients who received ACDF at the hospital, a follow-up period greater than 2 years was possible for 61 patients, including 30 in the PPC group and 42 in the N-PPC group. Evaluations were performed at 3, 6, 12, and 24 months after surgery. Radiological stabilization (RS) was defined as the restriction of spinous process movement to <3 mm and the absence of a halo around the cages on flexion-extension radiographs. Solid bone fusion (SBF) was defined as the formation of bony bridges between the fixed vertebral bodies in sagittal computed tomography sections. The rates of RS and SBF were compared between both groups. RESULTS: The differences in RS were not significant between the 2 groups during the follow-up period. However, the SBF rates at 6 and 12 months were significantly higher in the PPC group (26.7% and 56.7%) than in the N-PPC group (5% and 21.4%). Moreover, 63.3% (19 of 30) of patients in the PPC group demonstrated RS at 3 months, and of these patients, SBF was observed in 100% (19 patients) after 24 months, respectively. In comparison, the SBF rates in the N-PPC group were 86%. CONCLUSIONS: Plasmapore-coated titanium cages enabled more rapid solid bone fusion. We suggest that these types of cages might help to reduce postoperative radiograms.