Interim 1-Year Radiographic and Clinical Outcomes Following Anterior Cervical Discectomy and Fusion Using Hydroxyapatite-Infused Polyetheretherketone Interbody Cages.

BACKGROUND: This is a multicenter observational registry analysis of 1-year radiographic and clinical outcomes following anterior cervical discectomy and fusion (ACDF) using hydroxyapatite (HA)-infused polyetheretherketone (PEEK) intervertebral cages. METHODS: Radiographic and clinical outcome data were collected preoperatively and at 6 weeks, 3 months, 6 months, and 12 months postoperatively. To assess fusion, dynamic flexion-extension radiographs were independently evaluated with a validated method. Clinical outcomes were assessed using the following disease-specific measures: Neck Disability Index (NDI) and visual analog scale (VAS) for neck, left arm, and right arm pain. Patient satisfaction was also evaluated. RESULTS: A total of 789 ACDF patients (men: 51.5%/women: 48.5%; mean body mass index: 29.9 kg/m2) were included at the time of analysis, and 1565 segments have been operated. Successful fusion was confirmed in 91.3% of all operated levels after 6 months and 92.2% after 12 months. Mean NDI scores improved significantly (P < 0.01) preoperatively (46.3, n = 771) to postoperatively (12 months: 25.2, n = 281). Consistently, mean VAS neck (preoperative: 64.2, n = 770; 12 months: 28.6, n = 278), VAS right arm (preoperative: 42.6, n = 766; 12 months: 20.4, n = 277), and VAS left arm (preoperative: 41.1, n = 768; 12 months: 20.8, n = 277) decreased significantly (P < 0.01). Patients reported high satisfaction rates after surgery with no significant changes in postoperative patient satisfaction between 6 weeks and 12 months (95.1%, n = 273). CONCLUSIONS: ACDF with HA-infused PEEK cages demonstrates promising radiographic and clinical outcomes, supporting the potential benefits of incorporating HA into PEEK cages to enhance fusion rates and improve patient outcomes. CLINICAL RELEVANCE: This study demonstrates a >90% fusion rate by level with reliable improvements in patient reported outcomes, along with a high rate of patient satisfaction, in a large patient cohort undergoing ACDF with HA-infused PEEK cages. LEVEL OF EVIDENCE: 2 .

The risks and benefits of early venous thromboembolism prophylaxis after elective spinal surgery: A single-centre experience.

BACKGROUND: There is a wide ranging incidence of venous thromboembolism after surgery and it continues to be a major cause of morbidity after spinal procedures.This study's aim was to investigate the relationship between timing and administration of venous thromboembolism (VTE) pharmacologic chemoprophylaxis after spinal surgery and the resulting VTE and bleeding complications by reviewing current practices and outcomes at a high-volume single institution to better define opportunities for perioperative intervention to prevent VTE without increasing bleeding complications. METHODS: All patients who underwent elective one or two-stage lumbar spinal fusion procedures were identified. A logistic regression was used to evaluate (1) risk of symptomatic VTE within 30 days of surgery and (2) bleeding-related complications. The odds of developing a VTE as well as bleeding-related complications were compared among the three treatment groups: no chemoprophylaxis, chemoprophylaxis < 24h of surgery and chemoprophylaxis given > 24h post-surgery. RESULTS: When adjusted for doses administered, the odds of developing a postoperative VTE within 30 days were 0.189 (95% confidence interval (0.044, 0.808)) in patients who received anticoagulation < 24h postoperatively, compared to those who received no anticoagulation (p = 0.025). There was no difference in bleeding rates. CONCLUSION: Patients undergoing elective spinal surgery who received anticoagulation within 24h of the conclusion of their procedure had an 81% reduction in the odds of developing a deep vein thrombosis within 30 days with no significant difference in bleeding complications.

Clinical study to evaluate the safety and effectiveness of the Aesculap Activ-L artificial disc in the treatment of degenerative disc disease.

BACKGROUND: The objective of this clinical study is to evaluate the safety and effectiveness of the Activ-L Artificial Disc for treatment of single-level degenerative disc disease of the lumbar spine in patients who have been unresponsive to at least six months of prior conservative care. The hypothesis of the study is that the Activ-L Disc is non-inferior to the control (the Charité Artificial Disc [DePuy Spine] or ProDisc-L Total Disc Replacement [Synthes Spine]) with respect to the rate of individual subject success at 24 months. Individual subject success is a composite of effectiveness and safety. METHODS/DESIGN: The study proposed is a prospective, randomized, single-masked, controlled, multi-center clinical trial consisting of an estimated 414 subjects with single-level DDD of the lumbar spine (L4/L5, or L5/S1) who have failed to improve with conservative treatment for at least six months prior to enrollment. After enrollment, subjects will be randomized in a 2:1 ratio to either the Activ-L Disc (investigational device) or the control (Charité or ProDisc-L). Radiographic endpoints will be evaluated by an independent reviewer at an imaging core laboratory. Each subject will be followed for 5 years post-treatment. DISCUSSION: The safety and effectiveness of the Activ-L Artificial Disc for treatment of single-level degenerative disc disease of the lumbar spine will be equivalent to Charité Artificial Disc [DePuy Spine] or ProDisc-L Total Disc Replacement [Synthes Spine] at 24 months. TRIAL REGISTRATION: Current Controlled Trials NCT00589797.

Unintentional Epidural Anesthesia Mimicking Cauda Equina Syndrome from Suprafascial Injection of Liposomal Bupivacaine After Lumbar Foraminotomy: A Case Report.

CASE: This case report describes a 46-year-old woman undergoing right-sided L5 to S1 decompression who received liposomal bupivacaine (LB) for postoperative analgesia and developed unintentional epidural anesthesia with symptoms mimicking cauda equina syndrome. The patient's symptoms resolved 72 hours postoperatively, approximately the length that LB typically lasts. At the 16-month follow-up, the patient demonstrated complete neurological function with no lower extremity strength or sensation deficits. CONCLUSIONS: Tracking of LB into the epidural space after lumbar surgery may cause transient epidural anesthesia with symptoms that mimic cauda equina syndrome.

Time Savings and Related Economic Benefits of Suction-Curette Device for Transforaminal Lumbar Interbody Fusion Discectomy.

BACKGROUND: Performing an adequate transforaminal lumbar interbody fusion (TLIF) discectomy requires numerous instrument passes, increasing surgical time and the risk of complications. The purpose of this study was to evaluate the efficacy and efficiency of discectomy and endplate preparation during TLIF using traditional manual instrumentation versus a novel suction discectomy curette. The direct economic benefit with use of the suction discectomy curette is calculated. METHODS: Three experienced, spine-fellowship-trained surgeons performed TLIF discectomies on 3 cadaveric specimens from T12 to S1 using either traditional manual discectomy instruments or CONCORD Clear (Xtool) devices supplemented with manual discectomy instruments. For each level in which a discectomy was performed, the following were measured: elapsed time, number of instrument passes and the number of instrument exchanges, and estimated tissue volume. RESULTS: Transforaminal lumbar interbody fusion discectomy times improved on average 11:32 minutes per level, which equates to an estimated procedural time savings of 15:85 minutes, using 1.4 levels per TLIF, the average number of levels in a large series. Usage of the CONCORD Clear significantly reduced instrument passes compared to traditional, with a mean of 62.0 for traditional versus 7.1 for CONCORD Clear, an 8.7-fold improvement. Instrument exchanges showed a 5.9-fold improvement, with means of 26.8 and 4.6, respectively. Wet discectomy tissue volume was measured for each discectomy, with a mean of 5.4 cc for traditional versus 12.9 cc for CONCORD Clear, a 2.4-fold improvement. CONCLUSIONS: This study estimates that, in a typical TLIF procedure, over 15 minutes should be saved by using the CONCORD Clear l device (a quarter of the time of a traditional discectomy), and by considering the direct cost-benefit associated with this time savings as well as reduced sterilization costs, it is estimated that a hospital could save approximately $1300 in operating room time and sterilization cost with the use of the CONCORD Clear device in a typical 1-level TLIF procedure.

A comparison of patients who have undergone 1-Level versus 2-Level ProDisc arthroplasty: a prospective study with minimum of 5-year follow-up.

STUDY DESIGN: Analysis of data collected prospectively from the United States Food and Drug Administration Investigational Device Exemption (U.S. FDA IDE) clinical trial for patients who underwent ProDisc-L arthroplasty at 1- and 2- levels performed at 2 study centers. OBJECTIVE: To determine if there is any clinical or radiographical differences between patients who received 1-level ProDisc-L and patients who received 2-level ProDisc-L with a minimum follow-up of 5 years. SUMMARY OF BACKGROUND DATA: Recent prospective U.S. FDA clinical trial results have been published showing efficacy of the ProDisc (DePuy Synthes, West Chester, PA) prosthesis in both single and 2 level surgical procedures. Results of these prospective randomized multicenter FDA IDE clinical trials showed safety, efficacy, and superiority over circumferential fusion. METHODS: Patients were part of the FDA clinical trial for the ProDisc-L versus circumferential fusion study at 2 institutions. We identified 20 patients who received ProDisc-L at 1 level and 21 who received it at 2 levels for a total of 41 patients. Pre- and postoperative pain, clinical function, and range of motion were measured. An unpaired t test was done to compare the 2- versus 1-level disc replacement patients. RESULTS: All patients had more than 60 months of clinical follow-up. The mean scores on the visual analogue scale were 37.1 and 28.7, respectively (P = 0.33) for 1- and 2-level patients. Oswestry Disability Index scores were 33 and 29.1, respectively for 1- and 2-level patients (P = 0.60); and SF-36 health survey physical scores were 43 and 43.9, respectively for 1- and 2-level patients (P = 0.81); SF-36 health survey mental scores were 46.2 and 46.6, respectively for 1- and 2-level patients (P = 0.923). The average final follow-up postoperative range of motion for 1- and 2-level total disc replacement was 6.0º and 5.4º, respectively (P = 0.632). CONCLUSION: This study was unable to identify statistical differences in all clinical and radiographical outcomes for patients who underwent 1- and 2-level ProDisc arthroplasty in a cohort from 2 centers. Future studies with longer-term follow-up are needed to confirm these results. LEVEL OF EVIDENCE: 4.

Pediatric scoliosis.

Pediatric scoliosis is a relatively uncommon condition typically first noticed due to altered stature or by routine spine screenings by a school nurse or pediatrician. The formal diagnosis is made with spine radiographs, with coronal curvature measurement of 10° or greater. Treatment may consist of serial observation, bracing until skeletal maturity, or surgery for correction and fusion/stabilization of severe or progressive deformity. Overall success for non-operative management of scoliosis is affected by the etiology for the deformity, close follow up and monitoring for evolution of the deformity, and patient compliance with their treatment regimen. The most common surgical technique is a posterior approach spine fusion with implanted instrumentation, and patients are typically back to their activities of daily living by 6 months postoperatively. Continued intermittent monitoring of the scoliosis throughout adulthood is recommended, to detect late deformity progression, development of arthritis symptoms, or other associated issues.

Effect of active head restraint on residual neck instability due to rear impact.

STUDY DESIGN: An in vitro study of simulated whiplash using a hybrid cadaveric/surrogate model. OBJECTIVE: The goal of the present study was to determine the effect of the active head restraint (AHR) on residual neck instability due to simulated rear impacts of a human model of the neck. SUMMARY OF BACKGROUND DATA: Previous studies have indicated potential benefits of active injury prevention systems in reducing neck injuries during rear impacts. METHODS: Six osteoligamentous whole cervical spine specimens (occiput-T1) were prepared with vertebral motion tracking flags. The model, consisting of the neck specimen mounted to the torso of BioRID II and carrying an anthropometric surrogate head, was rear impacted (7.1 and 11.1 g) with and without the AHR. Pre- and post-impact flexibility tests identified significant residual instability (P < 0.05) above physiologic values and among experimental conditions. Linear regression analyses were used to identify correlation between spinal rotation peaks measured during impact and the resulting flexibility parameter increases (R² > 0.35 and P < 0.001). RESULTS: Our results indicated significant increases in the average flexibility parameters, up to 3.1°, at C2-C3, C3-C4, and C5-C6 due to 7.1 g rear impacts even in the presence of the AHR. Subsequently, increases in the flexibility parameters progressed and spread to head/C1 and to the inferior spinal levels following the 11.1 g impacts. Correlation was observed between the C7-T1 extension peaks measured during impact and the flexibility parameter increases measured following impact. The flexibility parameter increases were generally larger due to the impacts with no head restraint, as compared with the AHR. CONCLUSION: Extrapolation of our results indicated that every 1° of extension beyond the physiologic limit during whiplash contributed approximately 0.5° of residual neck rotation following whiplash. The present data underscore the protective effect of the AHR in reducing residual neck instability due to whiplash.

Biomechanics of halo-vest and dens screw fixation for type II odontoid fracture.

STUDY DESIGN: An in vitro biomechanical study of halo-vest and odontoid screw fixation of Type II dens fracture. OBJECTIVE: The objective were to determine upper cervical spine instability due to simulated dens fracture and investigate stability provided by the halo-vest and odontoid screw, applied individually and combined. SUMMARY OF BACKGROUND DATA: Previous studies have evaluated posterior fixation techniques for stabilizing dens fracture. No previous biomechanical study has investigated the halo-vest and odontoid screw for stabilizing dens fracture. METHODS: A biofidelic skull-neck-thorax model was used with 5 osteoligamentous whole cervical spine specimens. Three-dimensional flexibility tests were performed on the specimens while intact, following simulated dens fracture, and following application of the halo-vest alone, odontoid screw alone, and halo-vest and screw combined. Average total neutral zone and total ranges of motion at C0/1 and C1/2 were computed for each experimental condition and statistically compared with physiologic motion limits, obtained from the intact flexibility test. Significance was set at P < 0.05 with a trend toward significance at P < 0.1. RESULTS: Type II dens fracture caused trends toward increased sagittal neutral zone and lateral bending range of motion at C1/2. Spinal motions with the dens screw alone could not be differentiated from physiologic limits. Significant reductions in motion were observed at C0/1 and C1/2 in flexion-extension and axial rotation due to the halo-vest, applied individually or combined with the dens screw. At C1/2, the halo-vest combined with the dens screw generally allowed the smallest average percentages of intact motion: 3% in axial rotation, 17% in flexion-extension, and 18% in lateral bending. CONCLUSION: The present reduction in C1/2 motion observed, due to the halo-vest and dens screw combined is similar to previously reported immobilization provided by the polyaxial screw/rod system and transarticular screw fixation combined with wiring. The present biomechanical data may be useful to clinicians when choosing an appropriate treatment for those with Type II dens fracture.

Evaluation of Perivascular Adhesion Formation in New Zealand White Rabbits Using Oxiplex and DuraSeal Xact Adhesion Barrier System.

BACKGROUND: Adhesion formation after spine surgery is a result of normal wound healing that may place patients at increased risk for complications during revision surgery. Preventing adhesions could reduce the risk of complications during revision surgery, and possibly reduce the need for revision procedures. This study evaluates the ability of DuraSeal Xact Adhesion Barrier System (DSX) (Covidien, Mansfield, Massachusetts) and Oxiplex/SP gel (OX) (FzioMed, San Luis Obispo, California) to affect the extent and severity of postoperative perivascular adhesion development in an anterior spinal surgical rabbit model. METHODS: We determined the extent and severity of postoperative adhesion development 34 days after surgery in 12 male New Zealand White rabbits randomly assigned to intraoperative treatment with either DSX or OX, or to an untreated control group. Adhesion severity and extent were scored on scale from 0 (none) to 3 (severe). RESULTS: The extent and severity of adhesions in the DSX group were significantly less than in the untreated control group. The DSX group mean extent score was 1.3 ± 0.5 (vs 2.5, P = .01) and the mean severity score was 1.25 ± 0.5 (vs 2.8, P = .005). The extent and severity of adhesions in the OX group were not significantly different from the control group. CONCLUSION: In this study, we found DSX to be the most effective compound in preventing adhesion formation after anterior spine surgery. CLINICAL RELEVANCE: Extrapolating these results in rabbits to humans, less scarring between the major blood vessels could decrease the rate of complications in revision spine procedures.