Spinal Fusion

Study Design. The Oswestry Disability Index (ODI) has become one of the principal condition-specific outcome measures used in the management of spinal disorders. This review is based on publications using the ODI identified from the authors' personal databases, the Science Citation Index, and hand searches of Spine and current textbooks of spinal disorders.

In recent decades, the fastest growth in lumbar surgery occurred in older patients with spinal stenosis. Trials indicate that for selected patients, decompressive surgery offers an advantage over nonoperative treatment, but surgeons often recommend more invasive fusion procedures. Comorbidity is common in older patients, so benefits and risks must be carefully weighed in the choice of surgical procedure.

When measuring treatment effect in chronic low back pain with multi-item outcome instruments, it is necessary, both for clinical decision-making and research purposes, to understand the clinical importance of the outcome scores. The aims of the present study were three-fold. Firstly, it aimed to estimate the minimal clinically important difference of three multi-item outcome instruments (the Oswestry Disability Index, the General Function Score and the Zung Depression Scale) and of the visual analogue scale (VAS) of back pain. Secondly, it aimed to estimate the error of measurement of these instruments; and its third aim was to describe the clinical meaning of score change. The study population consisted of 289 patients treated surgically or non-surgically in a randomised controlled trial. The minimal clinically important difference was estimated with patient global assessment as the external criterion. It was compared with the standard error of measurement of the instruments. The i...

Given the number of spinal fusions performed annually, concerns have mounted over the potential for adjacent segment degeneration (radiographic changes of degeneration at levels adjacent to a spinal fusion) and adjacent segment disease (development of new symptoms correlating with adjacent segment degeneration). This article reviews documented evidence on adjacent segment degeneration and disease as it relates to cervical and lumbar arthrodesis. There appears to be an incidence of adjacent segment degeneration and disease after arthrodesis that may be related to natural degeneration or the adjacent fusion. It remains to be seen whether restoration of motion with disc arthroplasty will alter the rate of adjacent segment degeneration or disease. Ć 2004 Elsevier Inc. All rights reserved.

A primary concern after posterior lumbar spine arthrodesis is the potential for adjacent segment degeneration cephalad or caudad to the fusion segment. There is controversy regarding the subsequent degeneration of adjacent segments, and we are aware of no long-term studies that have analyzed both cephalad and caudad degeneration following posterior arthrodesis. A retrospective investigation was performed to determine the rates of degeneration and survival of the motion segments adjacent to the site of a posterior lumbar fusion. Two hundred and fifteen patients who had undergone posterior lumbar arthrodesis were included in this study. The study group included 126 female patients and eighty-nine male patients. The average duration of follow-up was 6.7 years. Radiographs were analyzed with regard to arthritic degeneration at the adjacent levels both preoperatively and at the time of the last follow-up visit. Disc spaces were graded on a 4-point arthritic degeneration scale. Correlatio...

Objectives: To assess a surgical technique and the postoperative outcomes of a consecutive series of 22 patients treated for degenerative lumbar spondylolisthesis (DLS) through a minimally invasive unilateral approach associating interbody fusion and percutaneous osteosynthesis. Patients and methods: Twenty-two patients were included in this study, with a mean age of 60 years (range, 35-77years). All had low-grade single-level DLS. In all cases, the technique included a posterior unilateral paramedial approach through a tubular retractor that decompressed the vertebral canal and transforaminal intervertebral cage arthrodesis. Osteosynthesis was then systematically put in place. The evaluation criteria were clinical (pain, spinal symptoms, duration of hospital stay) and radiological. The entire series was followed up for a mean of 24 months. Results: In this series, the procedure was performed with no technical problems. The mean hospital stay lasted 4.5days. Postoperative pain assessment showed a mean VAS of 2/10 at discharge and 75% of the patients were asymptomatic at 6 months. The radiological exams showed no extrapedicular screws and the fusion rate was 95% at the last follow-up (with one patient needing surgical revision for malunion). Conclusion: Transforaminal lumbar interbody fusion through a unilateral approach associated with percutaneous osteosynthesis is a reliable and effective technique in DLS surgery. The clinical and radiological results are encouraging, with low morbidity and a fusion rate comparable to conventional techniques. However, a longer follow-up will be necessary so as to assess the long-term results of this surgical strategy. Level of evidence: Level IV. Retrospective study.

Objectives To assess the clinical effectiveness of surgical stabilisation (spinal fusion) compared with intensive rehabilitation for patients with chronic low back pain. Design Multicentre randomised controlled trial. Setting 15 secondary care orthopaedic and rehabilitation centres across the United Kingdom. Participants 349 participants aged 18-55 with chronic low back pain of at least one year's duration who were considered candidates for spinal fusion. Intervention Lumbar spine fusion or an intensive rehabilitation programme based on principles of cognitive behaviour therapy. Main outcome measure The primary outcomes were the Oswestry disability index and the shuttle walking test measured at baseline and two years after randomisation. The SF-36 instrument was used as a secondary outcome measure. Results 176 participants were assigned to surgery and 173 to rehabilitation. 284 (81%) provided follow-up data at 24 months. The mean Oswestry disability index changed favourably from 46.5 (SD 14.6) to 34.0 (SD 21.1) in the surgery group and from 44.8 (SD14.8) to 36.1 (SD 20.6) in the rehabilitation group. The estimated mean difference between the groups was − 4.1(95% confidence interval − 8.1 to − 0.1, P = 0.045) in favour of surgery. No significant differences between the treatment groups were observed in the shuttle walking test or any of the other outcome measures. Conclusions Both groups reported reductions in disability during two years of follow-up, possibly unrelated to the interventions. The statistical difference between treatment groups in one of the two primary outcome measures was marginal and only just reached the predefined minimal clinical difference, and the potential risk and additional cost of surgery also need to be considered. No clear evidence emerged that primary spinal fusion surgery was any more beneficial than intensive rehabilitation.

Background: The management of degenerative spondylolisthesis associated with spinal stenosis remains controversial. Surgery is widely used and has recently been shown to be more effective than nonoperative treatment when the results were followed over two years. Questions remain regarding the long-term effects of surgical treatment compared with those of nonoperative treatment.

The expectations of both the patient and surgeon have been greatly revised in the last 10 years with the introduction of pedicle screws (PS) in spinal surgery. In this study, we have retrospectively evaluated and compared the results of PS instrumentation and the Hybrid System (HS), the latter consists of pedicle screws, sublaminar wire and hooks. The mean follow-up period was 60.1 months (range: 49–94 months) for the patients of the HS group and 29.3 months (range: 24–35 months) for those of the PS group. In the HS group, pedicle screws were used at the thoracolumbar junction and lumbar vertebra, the bilateral pediculotransverse claw hook configuration was used at the cranial end of the instrumentation, sublaminar wire was used on the concave side of the apical region and the compressive hook was used on the convex side. In the PS group, PS were used on the concave sides at all levels and on the convex side of the cranial and caudal end of instrumentation, in the transition zone and at the apex. The two groups were comparable for variables such as mean age, preoperative Cobb angle, thoracic kyphosis angle, lordosis angle, coronal balance, flexibility of the curve, apical vertebra rotation (AVR), apical vertebra rotation (AVT) and the number of vertebrae included in the fusion (p > 0.05). The parameters of values of correction, ratio of correction loss, AV derotation, AVT correction ratio, amount of blood loss, operation time, postoperative global coronal and sagittal balance, thoracic kyphosis angle and lumbar lordosis angle were measured at the last follow-up and used for comparing the HS and PS groups. There was no statistically significant difference between the groups for correction ratio, postoperative coronal balance, postoperative thoracic kyphosis and lumbar lordosis angle, operation time, amount of blood loss and number of fixation points (p > 0.05) The difference for the ratio of correction loss, AV derotation angle and the AVT correction ratio at the last follow-up visit and for the total follow-up period between the groups was found to be statistically significant (p < 0.05). Although it is possible to obtain a similar amount of correction by either instrumentation system, the loss of correction seems to be lower with the more rigid PS construction. The PS system also has a stronger effect on vertebral bodies, thereby providing better AV de-rotation. There was no significant difference (p > 0.05) between the groups in terms of correction rate, postoperative coronal and sagittal balance, operation time, blood loss and number of fixation points. This may indicate that anchor points are more important than the use – or not – of screws. Correction durability and AV de-rotation was better with PS instrumentation, while AVT was better corrected by HS instrumentation (p < 0.05). We propose that the reason for the better correction of AVT with HS instrumentation is the forceful translation offered by the sublaminar wire at the apical region, while the reason for the better correction durability of the PS instrumentation may be due to the fact that multiple pedicle screws which afford three-column control are better at maintaining the correction and preventing late deterioration. Dans la chirurgie rachidienne les attentes des patients et des chirurgiens se sont grandement modifiées depuis 10 ans, depuis l’introduction des vis pédiculaires (PS). Nous avons pour cette étude évalué de façon rétrospective et comparé les résultats de vis pédiculaires avec une instrumentation hybride (HS) utilisant à la fois des vis pédiculaires, des fils et des crochets sous laminaires. Matériel et méthode : le suivi moyen a été de 60.1 mois (49 – 94 mois) pour le groupe HS et de 29.3 mois (24 – 35 mois) pour le groupe PS. Dans le groupe HS, les vis pédiculaires ont été utilisées à la jonction dorsolombaire, thoracolombaire et au niveau lombaire avec un dispositif pédiculo transverse terminant le montage à la partie supérieure, les fils laminaires étant utilisés dans la partie concave et, dans la partie convexe avec un crochet en compression à la partie la plus apicale de la courbe. Dans le groupe vis pédiculaires, celles-ci ont été utilisées dans la partie concave à tous les niveaux et dans la partie convexe et caudale pour stabiliser l’instrumentation. Les groupes ont été très comparables en termes d’âges, d’angles de Cobb pré-opératoires, de cyphose thoracique, de lordose lombaire, de rotation et de souplesse de la courbe et de nombre de vertèbres inclus dans le montage (P > 0.05). Les valeurs de correction, de pertes de correction, de dérotation, de pertes sanguines, de temps opératoires, de cyphose thoracique et de lordose lombaire ont été mesurées à la dernière revue des patients en comparant les deux groupes HS et PS. Résultats : il n’y a pas de différences significatives entre ces deux groupes en ce qui concerne la correction post opératoire, la cyphose thoracique post opératoire, la lordose lombaire post opératoire, le temps opératoire, les pertes sanguines et le nombre de points de fixation du matériel (p > 0.05). Par contre, il existe une différence en ce qui concerne les pertes de correction et l’angle de rotation, il est possible d’obtenir une correction similaire avec chaque instrumentation. Les pertes de correction sont beaucoup moins importantes avec le système vis pédicullaires, plus rigides (PS) qui entraînent une meilleure rotation. En conclusion : pour le taux de correction post opératoire, le temps opératoire, les pertes sanguines, le nombre de points de fixation les deux groupes ne montrent pas de différences significatives (p > 0.05). Ceci nous indique que les points de fixation du matériel sont plus importants que l’utilisation de vis. La stabilité à long terme et la dérotation sont nettement améliorées avec l’instrumentation PS, l’AVT étant mieux corrigé avec l’instrumentation HS (p < 0.05). Nous pensons que pour avoir une meilleure correction de l’AVT comme réalisé avec l’instrumentation HS, il est nécessaire d’avoir une translation entraînée par les fils sous laminaires dans la région apicale. Par contre les raisons d’une meilleure correction et d’une meilleure stabilité dans le groupe PS sont secondaires aux multiples vis pédiculaires qui contrôlent beaucoup mieux les trois colonnes au niveau du montage avec une bonne stabilité empêchant une perte de correction secondaire.

The efficacy of fusion surgery in addition to decompression surgery in patients who have lumbar spinal stenosis, with or without degenerative spondylolisthesis, has not been substantiated in controlled trials. We randomly assigned 247 patients between 50 and 80 years of age who had lumbar spinal stenosis at one or two adjacent vertebral levels to undergo either decompression surgery plus fusion surgery (fusion group) or decompression surgery alone (decompression-alone group). Randomization was stratified according to the presence of preoperative degenerative spondylolisthesis (in 135 patients) or its absence. Outcomes were assessed with the use of patient-reported outcome measures, a 6-minute walk test, and a health economic evaluation. The primary outcome was the score on the Oswestry Disability Index (ODI; which ranges from 0 to 100, with higher scores indicating more severe disability) 2 years after surgery. The primary analysis, which was a per-protocol analysis, did not include...

BACKGROUND: Positive spinal regional and global sagittal malalignment has been repeatedly shown to correlate with pain and disability in thoracolumbar fusion. OBJECTIVE: To evaluate the relationship between regional cervical sagittal alignment and postoperative outcomes for patients receiving multilevel cervical posterior fusion. METHODS: From 2006 to 2010, 113 patients received multilevel posterior cervical fusion for cervical stenosis, myelopathy, and kyphosis. Radiographic measurements made at intermediate follow-up included the following: (1) C1-C2 lordosis, (2) C2-C7 lordosis, (3) C2-C7 sagittal vertical axis (C2-C7 SVA; distance between C2 plumb line and C7), (4) center of gravity of head SVA (CGH-C7 SVA), and (5) C1-C7 SVA. Health-related quality-of-life measures included neck disability index (NDI), visual analog pain scale, and SF-36 physical component scores. Pearson product-moment correlation coefficients were calculated between pairs of radiographic measures and health-r...

We reviewed 161 patients, from four centres in Switzerland, who had undergone posterior fusion of the upper cervical spine with transarticular screw fixation of the atlanto-axial joints. They were followed up for a mean 24.6 months. The vertebral artery and the medulla escaped injury and only 5.9% of the complications were directly related to the screws. The rate of pseudarthrosis was 0.6%.

Ischemia predisposes orthopaedic trauma patients to delayed fracture healing or non-union. The goal of this study was to test the ability of bone morphogenetic protein 7 (BMP7) to stimulate fracture repair in an ischemic environment. Ischemic fractures were generated in male adult mice by resecting the femoral artery prior to the creation of a non-stabilized tibia fracture. Recombinant human BMP7 (rhBMP7, 50µg) was injected into the fracture site immediately after surgery. Histomorphometric analyses revealed that rhBMP7 induced more cartilage at day 7, more callus and bone at days 14 and 28, and more adipose tissue and fibrous tissue at days 7, 14 and 28 compared to controls (n=5/group/time). At day 28, all fractures treated with rhBMP7 (50µg, n=5) healed, whereas only 3 of 5 control fractures exhibited slight bony bridging. In addition, we found that rhBMP7 (both 10 and 50µg) significantly increased the amount of cartilage compared to controls in stabilized fractures, confirming its chondrogenic effect. No significant effects of rhBMP7 on tissue vascularization were observed at 3 days after fracture. Lastly, using bone marrow transplantation we determined that no donor-derived osteocytes or chondrocytes were present in rhBMP7 treated fractures, suggesting rhBMP7 did not recruit mesenchymal stem cells from the bone marrow to the fracture site. In conclusion, our results indicate that rhBMP7 is a promising treatment for fractures with severely disrupted blood supply.

Rheumatoid arthritis affects millions of people all over the world. Up to 86% of cases involve cervical spine alterations. Cervical spine instability patterns related to rheumatoid arthritis are: atlanto-axial subluxation, basilar invagination and subaxial instability. Once neurological deficit develops, progression can be fast and even lead to death. Rheumatoid arthritis treatment is mainly nonsurgical. Current medication and treatment protocols may prevent or delay the development of atlanto-axial disease. Periodical clinical and radiological examination help diagnose patients who already have neurological symptoms or those who are at risk of developing them, and who should thus be considered for surgical treatment. Preoperative neurological deficit is a predictor of postoperative neurological recovery, thus the importance of early detection and referral of patients at risk. Surgical treatment should be performed in specialized centers, by multidisciplinary groups. Along with early intervention, this should help reduce perioperative complications.

Objective: Although many trials have been conducted to evaluate the benefits of off-pump coronary surgery, few have concentrated on graft patency. We sought to evaluate the impact of off-pump surgery on completeness of revascularization and graft patency compared with conventional surgery.

Study Design. The Morbidity and Mortality database of the Scoliosis Research Society (SRS) was queried as to the incidence and type of complications as reported by its members for the treatment of adolescent idiopathic scoliosis (AIS) with spinal fusion and instrumentation procedures regarding surgical approach (anterior, posterior, or combined anterior-posterior) during a recent 3-year period.

BACKGROUND CONTEXT: Bone morphogenetic protein-2 (BMP-2) (Infuse) has been approved for use in anterior lumbar fusion in conjunction with an LT cage. However, off-label use is seen with anterior cervical fusion, posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF). The Federal Food and Drug Administration trial of BMP-2 in a PLIF application was halted because of a high incidence of ectopic bone forming in the neural canal (75%). The authors did not find a correlation between ectopic bone and increased leg pain. They concluded that the ectopic bone was a radiographic phenomenon and not associated with clinical findings. Complications using BMP in the cervical spine have been reported. Heretofore, there has not been a similar warning voiced for use of BMP in a lumbar PLIF or TLIF. PURPOSE: The purpose was to report five cases of ectopic bone in the canal associated with PLIF/TLIF off-label use of BMP-2 potentially contributing to abnormal neurologic findings. STUDY DESIGN/SETTING: This is an observational cohort study of patients referred to a tertiary care private medical center. METHODS: This was a retrospective chart review of patients referred to a tertiary spine institute with complications after surgery where BMP-2 had been used in an off-label PLIF or TLIF application. Patient demographics, operating room (OR) notes from the index BMP surgery, imaging studies, and current clinical status were reviewed. RESULTS: Five cases of ectopic bone in the spinal canal with potential neurologic compromise were identified. CONCLUSIONS: It does appear that ectopic bone in the spinal canal associated with BMP-2 use in PLIF or TLIF may contribute to symptomatic neurologic findings in rare cases. Revision surgeries are difficult. This article challenges a previous publication, which concluded that the high incidence of ectopic bone was of no clinical significance. Isolating BMP anteriorly in the disc space using layered barriers of bone graft between the BMP and the annular defect may reduce the incidence of ectopic bone in the spinal canal. Surgeons need to weigh the benefits versus risks of any technology used off label when making treatment decisions with their patients. Ó

To determine the long term survival in patients with Duchenne muscular dystrophy (DMD) following spinal surgery and nocturnal ventilation.A retrospective review of 100 consecutive patients born between 1970 and 1990 was conducted.Forty-seven patients had surgical spinal fusion, 27 were subsequently ventilated. Fourteen patients received ventilation only. Thirty-nine patients received neither intervention. The age at which ventilation was required correlated with the age at which ambulation was lost. Those who walked for longer were less likely to require spinal surgery. Mean vital capacity dropped from 1.4 to 1.13 L 1 year post-operatively. Patients having both spinal surgery and ventilation had a median survival of 30 years whereas those who were only ventilated survived to 22.2 years.Nocturnal ventilation improves survival in DMD. Spinal surgery does not increase forced vital capacity but in combination with nocturnal ventilation further improves median survival to 30 years.

Delivery of recombinant proteins is a proven therapeutic strategy to promote endogenous repair mechanisms and tissue regeneration. Bone morphogenetic protein-2 (rhBMP-2) has been used to promote spinal fusion and repair of challenging bone defects; however, the current clinically-used carrier, absorbable collagen sponge, requires high doses and has been associated with adverse complications. We evaluated the hypothesis that the relationship between protein dose and regenerative efficacy depends on delivery system. First, we determined the dose-response relationship for rhBMP-2 delivered to 8-mm rat bone defects in a hybrid nanofiber mesh/alginate delivery system at six doses ranging from 0 to 5 mg. Next, we directly compared the hybrid delivery system to the collagen sponge at 0.1 and 1.0 mg. Finally, we compared the in vivo protein release properties of the two delivery methods. In the hybrid delivery system, bone volume, connectivity and mechanical properties increased in a dosedependent manner to rhBMP-2. Consistent bridging of the defect was observed for doses of 1.0 mg and greater. Compared to collagen sponge delivery at the same 1.0 mg dose, the hybrid system yielded greater connectivity by week 4 and 2.5-fold greater bone volume by week 12. These differences may be explained by the significantly greater protein retention in the hybrid system compared to collagen sponge. This study demonstrates a clear dose-dependent effect of rhBMP-2 delivered using a hybrid nanofiber mesh/alginate delivery system. Furthermore, the effective dose was found to vary with delivery system, demonstrating the importance of biomaterial carrier properties in the delivery of recombinant proteins.

The effectiveness of lumbar fusion for chronic low back pain after surgery for disc herniation has not been evaluated in a randomized controlled trial. The aim of the present study was to compare the effectiveness of lumbar fusion with posterior transpedicular screws and cognitive intervention and exercises. Sixty patients aged 25-60 years with low back pain lasting longer than 1 year after previous surgery for disc herniation were randomly allocated to the two treatment groups. Experienced back surgeons performed transpedicular fusion. Cognitive intervention consisted of a lecture intended to give the patient an understanding that ordinary physical activity would not harm the disc and a recommendation to use the back and bend it. This was reinforced by three daily physical exercise sessions for 3 weeks. The primary outcome measure was the Oswestry Disability Index (ODI). Outcome data were analyzed on an intention-to-treat basis. Ninety-seven percent of the patients, including seven of eight patients who had either not attended treatment (n = 5) or changed groups (n = 2), completed 1-year follow-up. ODI was significantly improved from 47 to 38 after fusion and from 45 to 32 after cognitive intervention and exercises. The mean difference between treatments after adjustment for gender was À7.3 (95% CI À17.3 to 2.7, p = 0.15). The success rate was 50% in the fusion group and 48% in the cognitive intervention/exercise group. For patients with chronic low back pain after previous surgery for disc herniation, lumbar fusion failed to show any benefit over cognitive intervention and exercises. Ó

BACKGROUND CONTEXT: The objective of the North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Lumbar Disc Herniation with Radiculopathy is to provide evidence-based recommendations to address key clinical questions surrounding the diagnosis and treatment of lumbar disc herniation with radiculopathy. The guideline is intended to reflect contemporary treatment concepts for symptomatic lumbar disc herniation with radiculopathy as reflected in the highest quality clinical literature available on this subject as of July 2011. The goals of the guideline recommendations are to assist in delivering optimum efficacious treatment and functional recovery from this spinal disorder.

Sykaras N, Triplett RG, Nunn ME, Iacopino AM, Opperman LA. Effect of recombinant human bone morphogenetic protein-2 on bone regeneration and osseointegration of dental implants Abstract: Recombinant human bone morphogenetic protein-2 (rhBMP-2) induced bone regeneration and osseointegration was evaluated in bony defects created within the hollow chamber of endosseous dental implants in 14 foxhound dogs. Bilateral extractions of mandibular premolars were performed and surgical implantation of 104 hollow cylinder implants followed after 8 weeks of healing. Experimental implants had their hollow chamber filled with 20 mg of rhBMP-2 delivered with a bovine collagen carrier, whereas the control implants had their apical chamber left empty. Dogs were followed for 2, 4, 8 and 12 weeks. Histomorphometric evaluation and immunohistochemical analysis were performed. Minimal bone was regenerated at 2 weeks for both groups. At 4 weeks, bone fill averaged 23.48% for the rhBMP-2 and 5.98% for the control group (PϽ0.05). At 8 weeks, mean bone fill was 20.94% and 7.75% for the rhBMP-2 and the controls, respectively (PϽ0.05). At 12 weeks, mean bone fill was 31.39% and 24.31% for the rhBMP-2 and control implants, respectively (PϾ0.05). Bone-implant contact (BIC) increased for both groups over time and at 8 weeks the rhBMP-2 BIC value was 18.65% and for the control 7.22% (PϽ0.05). At 12 weeks, the BIC was 43.78% and 21.05% for the rhBMP-2 and the control group, respectively (PϽ0.05). Immunohistochemical staining for type II collagen was positive only for parts of the collagen carrier and formation of cartilaginous intermediate was not observed in any of the specimens. The results suggest that, in confined defects adjacent to dental implants, rhBMP-2 can induce bone regeneration in close apposition to the implant surface.

Bone fusion represents a challenge in the orthopedics practice, being especially indicated for spine disorders. Spinal fusion can be defined as the bony union between two vertebral bodies obtained through the surgical introduction of an osteoconductive, osteoinductive, and osteogenic compound. Autogenous bone graft provides all these three qualities and is considered the gold standard. However, a high morbidity is associated with the harvest procedure. Intensive research efforts have been spent during the last decades to develop new approaches and technologies for successful spine fusion. In recent years, cell and gene therapies have attracted great interest from the scientific community. The improved knowledge of both mesenchymal stem cell biology and osteogenic molecules allowed their use in regenerative medicine, representing attractive approaches to achieve bone regeneration also in spinal surgery applications. In this review we aim to describe the developing gene-and cell-based bone regenerative approaches as promising future trends in spine fusion.

Since the identification of the osteogenic protein-1 (OP-1) gene, also called bone morphogenetic protein-7 (BMP-7), almost 20 years ago, OP-1 has become one of the most characteristic members of the BMP family. The biological activity of recombinant human OP-1 has been defined using a variety of animal models. These studies have demonstrated that local implantation of OP-1 in combination with a collagen matrix results in the repair of critical size defects in long bones and in craniofacial bones and the formation of bony fusion masses in spinal fusions. Clinical trials investigating long bone applications have provided supportive evidence for the use of OP-1 in the treatment of open tibial fractures, distal tibial fractures, tibial nonunions, scaphoid nonunions and atrophic long bone nonunions. Clinical studies investigating spinal fusion applications have provided supportive evidence for the use of OP-1 in posterolateral lumbar models and compromised patients as an adjunct or as a replacement for autograft. Both long bone repair and spinal fusion studies have demonstrated the efficacy and safety of OP-1 by clinical outcomes and radiographic measures. Future clinical investigations will be needed to better define variables, such as dose, scaffold and route of administration. Clearly the use of BMPs in orthopaedics is still in its formative stage, but the data suggest an exciting and promising future for the development of new therapeutic applications.

The reported complication rates after various surgical techniques used to create a lumbar fusion vary within wide ranges. In a previous paper, the Swedish Lumbar Spine Study Group have reported on the clinical outcome of lumbar spine fusion for chronic low back pain in a comparably homogeneous patient population where there were no significant differences between baseline sociodemographic, clinical and paraclinical characteristics. In this report we compared the complication rates of the surgical procedures used in that study and analyzed the association between complications and baseline variables, and between outcome results and complications. A multicenter randomized study was conducted where 211 patients aged 25-65 were treated with lumbar fusion according to three different surgical techniques: noninstrumented posterolateral fusion (PLF, n=71), instrumented posterolateral fusion (VSP, n=68), and in the third procedure we added an interbody fusion with solid autogenous bone graf...

Objective. To test whether elastic stabilization with the Dynesys system (Zimmer Spine, Minneapolis, MN) provides enough stability to prevent further progression of spondylolisthesis as well as instability after decompression for spinal stenosis with degenerative spondylolisthesis.

BACKGROUND CONTEXT: Despite improvements through the use of prophylactic systemic antibiotics, surgical site infections remain a significant problem in the treatment of traumatic spine injuries. Infection rates as high as 10% have been reported in this population. The impact on patients and cost of treating such infections is profound. Local delivery of antibiotics has been found to be efficacious in animal and human studies as an adjunct to systemic antibiotics in surgical site infection prophylaxis. PURPOSE: To evaluate the efficacy of using vancomycin powder in surgical sites to prevent infections. STUDY DESIGN: Retrospective case review. PATIENT SAMPLE: Patients who underwent posterior spine fusions for traumatic injuries over a 2-year period at a single academic center. OUTCOME MEASURES: Clinical outcome determined was the incidence of either superficial or deep postoperative wound infections. METHODS: A retrospective review of 110 patients with traumatic spine injuries treated with instrumented posterior spine fusions over a 2-year period at a single academic center was performed. One group (control group) received standard systemic prophylaxis only, whereas another (treatment group) received vancomycin powder in the surgical wound in addition to systemic prophylaxis. Patient demographics and perioperative information obtained included history of previous spine surgeries, substance use, diabetes, body mass index, level of injury, presence of neurologic deficit, operative time, and estimated blood loss. Incidence of infection was the primary outcome evaluated. RESULTS: The control (N554) and treatment groups (N556) were statistically similar. A statistically significant difference in infection rate was found between the treatment group (0%) and control group (13%, p5.02) without any adverse events. No adverse effects were noted from use of the vancomycin powder. CONCLUSIONS: The use of vancomycin powder in surgical wounds may significantly reduce the incidence of infection in patients with traumatic spine injuries treated with instrumented posterior spine fusion. Applying vancomycin powder to surgical wounds is a promising means of preventing FDA device/drug status: Not approved for this indication (vancomycin powder).

BACKGROUND CONTEXT: The transforaminal lumbar interbody fusion (TLIF) procedure has become an increasingly popular means of obtaining a circumferential fusion while avoiding the morbidity of the anterior approach. Concerns remain, however, regarding the clinical efficacy and safety of its use. PURPOSE: The purpose of this study was to evaluate the complications of the single-level TLIF procedure. The difference in complications observed with the use of iliac crest autograft compared with rhBMP-2 will be assessed. STUDY DESIGN: Retrospective cohort study; a review of complications. METHODS: Patients who underwent a single-level TLIF between January 2004 to May 2007 with either autograft iliac crest or rhBMP-2 were identified. A retrospective review of these patients included operative reports, pre-and postoperative medical records, most recent postoperative dynamic and static lumbar radiographs, and computed tomography scans (when available). RESULTS: A total of 130 patients met the study criteria; 119 patients were available for follow-up, with an average radiographic follow-up of 19.1 months and an average clinical follow-up of 27.6 months. Thirty-three patients received iliac crest autograft and 86 patients received rhBMP-2. Complications occurred in 40 of the 119 study patients (33.6%). The autograft group had a higher complication rate (45.5% vs. 29.1%), but the difference was not statistically significant (p5.09). Complications in the autograft group included persistent donor-site pain (30.3%), donor-site infection (3.1%), lumbar wound infection (6.1%), and postoperative radiculitis (3.0%). Complications in the rhBMP-2 group included postoperative radiculitis (14.0%), vertebral osteolysis (5.8%), ectopic bone formation (2.3%), and lumbar wound infection (3.5%). A hydrogel sealant (Duraseal; Confluent Surgical Inc., Waltham, MA, USA) was used in 37 out of 86 patients in the rhBMP-2 group. The use of this sealant decreased the rate of postoperative radiculitis in the rhBMP-2 group from 20.4% to 5.4% (p5.047). The radiographic nonunion rate at most recent follow-up was 3.0% in the autograft group and 3.5% (p5.90) in the rhBMP-2 group. CONCLUSIONS: The most common complications in the autograft group were related to the donor site. The most common complication in the rhBMP-2 group was postoperative radiculitis, the incidence of which is reduced by the use of a hydrogel sealant.

Robotic-guided and percutaneous pedicle screw placement are emerging technologies. We here report a retrospective cohort analysis comparing conventional open to open robotic-guided and percutaneous robotic-guided pedicle screw placement. 112 patient records and CT scans were analyzed concerning the intraoperative and perioperative course. 35 patients underwent percutaneous, 20 open robotic-guided and 57 open conventional pedicle screw placement. 94.5% of robot-assisted and 91.4% of conventionally placed screws were found to be accurate. Percutaneous robotic and open robotic-guided subgroups did not differ obviously. Average X-ray exposure per screw was 34 s in robotic-guided compared to 77 s in conventional cases. Subgroup analysis indicates that percutaneously operated patients required less opioids, had a shorter hospitalization and lower rate of adverse events in the perioperative period. The use of robotic guidance significantly increased accuracy of screw positioning while reducing the X-ray exposure. Patients seem to have a better perioperative course following percutaneous procedures.

Recently, Van Limbeck et al., in a systematic literature review, failed to identify the best method for a single-level anterior cervical interbody fusion [13]. With the introduction of different interbody fusion devices, such as cages, surgical strategies to achieve anterior cervical fusion have evolved. The first papers on such promising techniques have been published . However, Wigfield, in a thorough literature review, concluded that there was limited evidence supporting the use of a cervical interbody fusion device in place of autologous bone .

Despite substantial attention given to the development of osteoregenerative biomaterials, severe deficiencies remain in current products. These limitations include an inability to adequately, rapidly, and reproducibly regenerate new bone; high costs and limited manufacturing capacity; and lack of surgical ease of handling. To address these shortcomings, we generated a new, synthetic osteoregenerative biomaterial, hyperelastic &quot;bone&quot; (HB). HB, which is composed of 90 weight % (wt %) hydroxyapatite and 10 wt % polycaprolactone or poly(lactic-co-glycolic acid), could be rapidly three-dimensionally (3D) printed (up to 275 cm(3)/hour) from room temperature extruded liquid inks. The resulting 3D-printed HB exhibited elastic mechanical properties (~32 to 67% strain to failure, ~4 to 11 MPa elastic modulus), was highly absorbent (50% material porosity), supported cell viability and proliferation, and induced osteogenic differentiation of bone marrow-derived human mesenchymal stem ...

Morbidity associated with autologous bone graft harvest is an important factor in determining the utility of expensive alternatives such as recombinant bone morphogenic protein. The most frequently reported complication associated with graft harvest is chronic pain. To prospectively determine the degree of pain and morbidity associated with autologous iliac crest bone graft harvest and its effect on activities of daily living. Prospective observational cohort study. One hundred ten adult patients undergoing elective posterior lumbar spinal fusion surgery involving autologous iliac crest bone graft harvest. Patient self-reported Visual Analog Scale (VAS) scores for pain and a study-specific questionnaire regarding activities of daily living. One hundred ten patients were prospectively enrolled. Postoperative VAS scores (0-100) for harvest site pain were obtained at 6-week, 6- and 12-month follow-up. Patients completed a 12-month questionnaire regarding the persistence of specific sym...

Background: Available clinical data are insufficient for comparing minimally invasive (MI) and open approaches for transforaminal lumbar interbody fusion (TLIF). To date, a paucity of literature exists directly comparing minimally invasive (MI) and open approaches for transforaminal lumbar interbody fusion (TLIF). The purpose of this study was to directly compare safety and effectiveness for these two surgical approaches. Materials and Methods: Open or minimally invasive TLIF was performed in 63 and 76 patients, respectively. All consecutive minimally invasive TLIF cases were matched with a comparable cohort of open TLIF cases using three variables: diagnosis, number of spinal levels, and history of previous lumbar surgery. Patients were treated for painful degenerative disc disease with or without disc herniation, spondylolisthesis, and/or stenosis at one or two spinal levels. Clinical outcome (self-report measures, e.g., visual analog scale (VAS), patient satisfaction, and MacNab's criteria), operative data (operative time, estimated blood loss), length of hospitalization, and complications were assessed. Average follow-up for patients was 37.5 months. Results: The mean change in VAS scores postoperatively was greater (5.2 vs. 4.1) in the open TLIF patient group (P = 0.3). MacNab's criteria score was excellent/good in 67% and 70% (P = 0.8) of patients in open and minimally invasive TLIF groups, respectively. The overall patient satisfaction was 72.1% and 64.5% (P = 0.4) in open and minimally invasive TLIF groups, respectively. The total mean operative time was 214.9 min for open and 222.5 min for minimally invasive TLIF procedures (P = 0.5). The mean estimated blood loss for minimally invasive TLIF (163.0 ml) was significantly lower (P < 0.0001) than the open approach (366.8 ml). The mean duration of hospitalization in the minimally invasive TLIF (3 days) was significantly shorter (P = 0.02) than the open group (4.2 days). The total rate of neurological deficit was 10.5% in the minimally invasive TLIF group compared to 1.6% in the open group (P = 0.02). Conclusions: Minimally invasive TLIF technique may provide equivalent long-term clinical outcomes compared to open TLIF approach in select population of patients. The potential benefit of minimized tissue disruption, reduced blood loss, and length of hospitalization must be weighted against the increased rate of neural injury-related complications associated with a learning curve.