Porous Polyetheretherketone Interbody Cages for Anterior Cervical Discectomy and Fusion at 3 or More Levels: Clinical and Radiographic Outcomes.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) at 3 or more levels remains challenging, with reported high pseudarthrosis rates and implant-related complications. Porous surface polyetheretherketone (PEEK) interbody cages are newer implants for ACDF with limited data available for their use in ACDF procedures at 3 or more levels. The objective of this study was to assess the clinical and radiographic outcomes of porous PEEK devices for ACDF at 3 or more levels. STUDY DESIGN: Retrospective case series. METHODS: Consecutive patients who underwent primary ACDF for degenerative cervical disc disease at 3 or more levels with porous PEEK cages with anterior plate instrumentation were included. Clinical outcome scores, radiographic parameters, pseudarthrosis rates, and cage subsidence rates were assessed. Preoperative and postoperative clinical outcomes and radiographic measures were compared using paired t tests. RESULTS: A total of 33 patients with ACDF at 3 or more levels with porous PEEK cages were included, with minimum 1-year follow-up. Two patients had cage subsidence (6.1%), and 1 patient had pseudarthrosis (3.0%). There were significant postoperative increases in overall cervical lordosis, sagittal vertical axis, fusion segment lordosis, T1 slope, and disc height. Clinical outcomes showed significant improvement from the preoperative visit to the final postoperative follow-up. CONCLUSIONS: High rates of fusion (97.0%) were observed in this challenging patient cohort, which compares favorably with previously published rates of fusion in ACDF at 3 or more levels. CLINICAL RELEVANCE: The optimal management of cervical spinal pathology regarding approach, technique, and implants used is an active area of ongoing investigation. The high levels of radiographic and clinical success utilizing a relatively novel implant material in a high-risk surgical cohort reported here may influence surgical decision making.

Clinical and radiographic outcomes using third-generation bioactive glass as a bone graft substitute for multi-level anterior cervical discectomy and fusion-a retrospective case series study.

BACKGROUND: Bioactive glasses have unique bone forming properties that have been used as a bone graft substitute for anterior cervical discectomy and fusions (ACDFs). Bone graft substitutes are used for achieving fusion while simultaneously avoiding donor site morbidity of iliac crest autograft. In this study, our principal intention is to assess the clinical and radiographic outcomes in patients with multi-level cervical disc disease undergoing ACDF using a third-generation bioactive glass as a bone graft substitute. METHODS: A retrospective case series study was performed of patients who underwent primary multi-level instrumented fusions for degenerative cervical disc disease with bioactive glass bone graft substitute between May 2016 and December 2017 by a single fellowship-trained spine surgeon. All patients were treated with a porous PEEK interbody spacer and with a third-generation bioactive glass synthetic bone graft substitute. Patients were assessed pre-operatively, immediately following surgery, and at 3, 6, 12, and 24 months. Accepted standard outcome measures were applied to evaluate preoperative and postoperative metrics, including Visual Analog Scale neck pain and arm pain, and Neck Disability Index. Dynamic lateral radiographs were used to assess sagittal alignment, disc space height, arthrodesis status, osseous integration, and implant migration. Sagittal plane angulation was measured by Cobb's criteria. RESULTS: Thirty-nine patients underwent multi-level instrumented fusions: seventeen (43%) were two-level; 12 (31%) were three-level; 9 (23%) were four-level; and 1 (3%) was five-levels. All patients were followed for a minimum of 6 months for mean of 16.0 months (range, 6 to 36 months); none were lost to follow-up. Significant improvements from preoperative scores in Neck Disability Index scores as well as neck and arm visual analog scale pain scores were realized. All patients either maintained or improved their neurological status. Radiographically, all patients were fused by 6 months postoperatively and showed improvement in fusion segment lordosis (Pre-Post and Pre-Final P<0.001), C2-C7 lordosis angle (Pre-Post and Pre-Final P<0.001), T1 slope (Pre-Post P=0.01, Pre-Final P=0.07) and maintenance of disc height (Post-Final P=0.02). There were no adverse events, infections, or reoperations. CONCLUSIONS: Third-generation bioactive glass synthetic graft is a viable alternative to allograft or autograft in the setting of multi-level instrumented fusions for achieving improved clinical and radiographic outcomes.

Clinical experience with the use of a spherical bioactive glass putty for cervical and lumbar interbody fusion.

BACKGROUND: A retrospective clinical case series study was conducted to evaluate the use of a novel, spherical bioactive glass bone graft (BioSphere Putty) as a graft material for cervical and lumbar interbody fusion. METHODS: Data was collected from a single surgeon using BioSphere Putty along with standardized hardware in anterior cervical decompression and fusion (ACDF), transforaminal lumbar interbody fusion (TLIF), and anterior lumbar interbody fusion (ALIF) surgical procedures. BioSphere Putty was used in combination with cancellous allograft (ACDF and ALIF) or in combination with autograft (TLIF). Clinical outcomes were assessed at 1- and 2-year using radiographic imaging and the visual analog pain scale (VAS). VAS scores at the 1- and 2-year follow-up periods were statistically compared to pre-operative scoring. Successful clinical outcomes were determined by a combination of the presence of a complete radiographic fusion and a decrease in VAS at 1-year and 1- and 2-year follow-up periods. RESULTS: The retrospective review of the patient data identified 248 cases that had either 1- or 1- & 2-year follow-up. This consisted of 115 ACDF procedures and 133 lumbar fusion procedures. Lumbar fusion cases were further sub-grouped with 103 patients undergoing TLIF procedures and 30 patients undergoing ALIF procedures. The global results for the series as a whole showed clinical outcomes comparative to other advanced biologic bone grafts. Radiographically all patients demonstrated fusion (100% fusion rate) and there were no clinical adverse events, infections, or graft-related complications in any of the patients in the series. One-year VAS scores were consistent with historical norms and demonstrated significant decreases in pre-operative pain for both ACDF patients (78% decrease) and lumbar patients (66% decrease TLIF/ALIF) (t test, P<0.05). By 2 years, VAS scores continued to drop with significant decreases for the ACDF patients (96%), TLIF patients (82%), and ALIF patients (80%) (t test, P<0.05). VAS scores were also assessed for each individual patient. The data showed a VAS score decrease from pre-operative levels in 93% of the ACDF patients and 89% of the lumbar patients. Combined with the 100% radiographic fusion rate in all patients, this resulted in a in a clinical success rate of 93% for the ACDF patients and 89% for the lumbar patients. CONCLUSIONS: The results of this clinical case series demonstrated that BioSphere Putty is a clinically effective and versatile synthetic bone graft material in the spine.

Impaction durability of porous polyether-ether-ketone (PEEK) and titanium-coated PEEK interbody fusion devices.

BACKGROUND CONTEXT: Various surface modifications, often incorporating roughened or porous surfaces, have recently been introduced to enhance osseointegration of interbody fusion devices. However, these topographical features can be vulnerable to damage during clinical impaction. Despite the potential negative impact of surface damage on clinical outcomes, current testing standards do not replicate clinically relevant impaction loading conditions. PURPOSE: The purpose of this study was to compare the impaction durability of conventional smooth polyether-ether-ketone (PEEK) cervical interbody fusion devices with two surface-modified PEEK devices that feature either a porous structure or plasma-sprayed titanium coating. STUDY DESIGN/SETTING: A recently developed biomechanical test method was adapted to simulate clinically relevant impaction loading conditions during cervical interbody fusion procedures. METHODS: Three cervical interbody fusion devices were used in this study: smooth PEEK, plasma-sprayed titanium-coated PEEK, and porous PEEK (n=6). Following Kienle et al., devices were impacted between two polyurethane blocks mimicking vertebral bodies under a constant 200 N preload. The posterior tip of the device was placed at the entrance between the polyurethane blocks, and a guided 1-lb weight was impacted upon the anterior face with a maximum speed of 2.6 m/s to represent the strike force of a surgical mallet. Impacts were repeated until the device was fully impacted. Porous PEEK durability was assessed using micro-computed tomography (µCT) pre- and postimpaction. Titanium-coating coverage pre- and postimpaction was assessed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy. Changes to the surface roughness of smooth and titanium-coated devices were also evaluated. RESULTS: Porous PEEK and smooth PEEK devices showed minimal macroscopic signs of surface damage, whereas the titanium-coated devices exhibited substantial visible coating loss. Quantification of the porous PEEK deformation demonstrated that the porous structure maintained a high porosity (>65%) following impaction that would be available for bone ingrowth, and exhibited minimal changes to pore size and depth. SEM and energy dispersive X-ray spectroscopy analysis of titanium-coated devices demonstrated substantial titanium coating loss after impaction that was corroborated with a decrease in surface roughness. Smooth PEEK showed minimal signs of damage using SEM, but demonstrated a decrease in surface roughness. CONCLUSION: Although recent surface modifications to interbody fusion devices are beneficial for osseointegration, they may be susceptible to damage and wear during impaction. The current study found porous PEEK devices to show minimal damage during simulated cervical impaction, whereas titanium-coated PEEK devices lost substantial titanium coverage.

Management of proximal femoral shaft fractures in osteopetrosis: a case series using internal fixation.

Osteopetrosis is a group of rare sclerosing bone dysplasias. Orthopedic concerns in osteopetrosis are principally related to the characteristic brittle "marble bone" in which fractures may be easily induced by relatively low-energy mechanisms. Femoral fractures are common in this patient population, and management presents a unique technical challenge. While osteopetrotic bone may be penetrated with a drill bit, the drill bit flutes are immediately filled with bone. This renders the drill ineffective, and generation of significant frictional heat can result in breakage of the drill. This case series describes the long-term management of nine osteopetrotic femoral fractures in three patients. The difficulties encountered in these cases prompted the development of a safe and efficacious technique for intramedullary fixation of these fractures.

Drug-related problem classification systems.

OBJECTIVE: To provide an overview of and critically appraise classifications of drug-related problems (DRPs) for use during the pharmaceutical care process and research in pharmacy. DATA SOURCES: A literature search was conducted using MEDLINE and Yahoo (January 2003) and manually. The search terms included DRP, drug-related problem, drug-therapy problem, and medicine-related problem. STUDY SELECTION AND DATA EXTRACTION: English- and German-language articles on pharmaceutical care and DRPs were reviewed. DATA SYNTHESIS: Most classifications of DRPs were identified through searching publications on pharmaceutical care and DRPs. Fourteen classifications with different focuses were found. Some classifications were hierarchical, categorized into main groups and subgroups. Various terminologies and definitions for DRPs were revealed, as well as guidelines for an optimal DRP classification. Classifications were assessed according to a clear definition, published validation method, and results reflecting process and outcomes, usability in pharmaceutical care practice, and a hierarchical structure with main groups and subgroups. CONCLUSIONS: Finding DRP classifications by computerized search of the biomedical literature with the help of PubMed proved to be difficult. No classification could be found that met all of our criteria for an optimal system. Few classifications have been validated. Three have been tested as to their usability in practice and internal consistency. The Pharmaceutical Care Network Europe system Version 4 comes closest to the defined requirements.

Regulation of Arctic char (Salvelinus alpinus) egg shell proteins and vitellogenin during reproduction and in response to 17beta-estradiol and cortisol.

Estrogens induce both vitellogenin (Vtg) and egg shell (zona pellucida; ZP) protein synthesis in salmonids. However, while Vtg is strictly under estrogenic control, recent reports suggest that additional mechanisms are involved in ZP protein synthesis. During sexual maturation both estrogen and glucocorticoid levels increase in the circulation of female fish. As glucocorticoids have been shown to interfere with Vtg induction in fish we investigated whether cortisol (F) had similar effects on ZP regulation. In the present study we determined both the natural variation in Vtg and ZP during an annual reproductive cycle in female Arctic char (Salvelinus alpinus), and the effect of co-treatment of juvenile Arctic char with 17beta-estradiol (E2) and F. During sexual maturation the expression of Vtg and ZP correlated to plasma levels of E2 and F. Determination of Vtg and ZP protein levels following co-treatment with E2 and F showed that F antagonized E2 induction of Vtg. However, F was observed to potentiate the expression of ZP protein in the same fish. These results indicate that in Arctic char Vtg and ZP proteins are not regulated by the same mechanisms and suggest that ZP protein expression does not necessarily imply exposure to estrogenic compounds alone, and may thus not be ideally suited as a biomarker of exposure to estrogenic compounds.

Pharmacy practitioners' views on computerized documentation of drug-related problems.

OBJECTIVE: To evaluate the practice by community pharmacy practitioners of computerized documentation of drug-related problems (DRPs) and pharmacy interventions in nonprescription drug consumers. METHODS: A questionnaire was administered in December 1999 to pharmacy practitioners in 45 community pharmacies of different sizes and locations across Sweden to survey their attitudes and experiences after participation in a 10-week period of computerized DRP documentation. RESULTS: The participants (n = 376, response rate 84%) found the development of computerized documentation of DRPs and pharmacy interventions to be very important. The instrument was perceived as easy to learn and to work well in daily practice. The documentation made many practitioners more attentive to the drug-related needs of self-care consumers and changed their perception of good quality in self-care counseling. The weighted multiple linear regression analysis showed no correlation between the proportion of practitioners experiencing time constraints and the DRP documentation rate of their work site. However, the magnitude of interest in the documentation practice had a significant effect on the documentation rate, regardless of the extent of the time constraints experienced (p = 0.004). CONCLUSIONS: The positive findings of the evaluation speak in favor of an expanded implementation of computerized documentation of DRPs and pharmacy interventions. Commitment among participating pharmacy practitioners to the new practice is essential and appears to overcome possible time constraints.

Nonprescription drug-related problems and pharmacy interventions.

OBJECTIVE: To document the number and types of drug-related problems (DRPs) identified in customers purchasing nonprescription products in Swedish pharmacies; describe the distribution of DRPs by customer's gender, age, underlying ailment, and class of drug; determine whether problems are identified to the same extent in pharmacies with staffed nonprescription self-service departments as in pharmacies with over-the-counter sales; and document the number and types of pharmacy interventions to prevent or resolve DRPs, including reasons for drug switches and referrals to physicians. METHODS: A computerized instrument for documentation of DRPs and pharmacy interventions was developed. The study was conducted in 45 volunteer pharmacies in Sweden during 10 weeks in late 1999. RESULTS: A total of 1,425 problems and 2,040 interventions were recorded by 308 pharmacy practitioners. Relatively fewer DRPs were documented in pharmacies with self-service departments. The most common DRPs were uncertainty about the indication for the drug (33.5%) and therapy failure (19.5%). Dyspepsia was the most frequently specified symptom (11.4%). Consumers of dermatologic products had significantly higher rates of problems than expected in relation to sales volume. The most common ways of responding to a problem were with consumer drug counseling (61.1%), switching of drugs (43.9%), and referral to a physician (27.5%). CONCLUSIONS: The study has demonstrated a need for more professional attention and intervention by pharmacy staff to prevent and rectify DRPs in nonprescription consumers. It seems especially important to make sure that consumers receive the appropriate drugs for their current ailments.

Posterior-only unit rod instrumentation and fusion for neuromuscular scoliosis.

STUDY DESIGN: A retrospective study to determine the efficacy of posterior-only unit rod instrumentation and fusion in a skeletally immature neuromuscular scoliosis population. OBJECTIVE: To determine whether the posterior-only approach to this population adequately addresses the concerns of correction of scoliosis and pelvic obliquity, maintenance of that correction over time, and the incidence of crankshaft phenomenon. SUMMARY OF BACKGROUND DATA: Controversy exists regarding the need for anterior release to improve curve flexibility and the need to obtain an anterior arthrodesis in those skeletally immature patients at risk for crankshafting with continued anterior growth. METHODS: From 1992 through 1997, 28 consecutive skeletally immature patients with neuromuscular scoliosis underwent posterior-only unit rod instrumentation and fusion for the treatment of progressive, symptomatic spinal deformities. Preoperative, immediate postoperative, and final follow-up radiographs were analyzed with respect to scoliosis and pelvic obliquity correction, maintenance of that correction over time, and the development of the crankshaft phenomenon as evidenced by loss of correction and/or increased rib-vertebral angle difference. The average age of the patients was 12.8 years and the average follow-up was 58 months with a minimum of 2 years. RESULTS: Twenty-six patients were available for final follow-up. The initial Cobb angle correction averaged 66%, with 75% of the pelvic obliquity corrected. These corrections were maintained over time. Before surgery 27 of 28 patients were Risser 0, 1, or 2. The triradiate cartilage was open in nine patients, and five patients were < or =10 years of age. At the final follow-up 22 of the 26 patients were Risser 5 and 4 were Risser 4. There was one patient with increased rib-vertebral angle difference over the length of follow-up, with no loss of frontal or sagittal plane alignment. CONCLUSIONS: These results indicate that even in the very young neuromuscular patient, acceptable amounts of curve correction can be achieved and maintained with posterior-only unit rod instrumentation and fusion. The biomechanical stiffness of this construct seemed to be able to prevent the crankshaft phenomenon in the majority of those patients at risk.

Expression of three vitelline envelope protein genes in arctic char.

Several studies have shown effects of estrogenic substances on endocrine and reproductive systems in wildlife. Measurement of plasma vitellogenin (VTG) is a commonly used method to determine exposure to estrogenic substances in fish. There is, however, a growing need for additional sensitive and accurate methods to detect estrogenic substances in vivo. The vitelline envelope proteins (VEPs) have been suggested, in other studies, as suitable biomarkers for estrogenic substances. The present study investigates the induction of VEPs in juvenile Arctic char (Salvelinus alpinus). The results demonstrate that VEP mRNA exhibits earlier induction than estrogen receptor mRNA or VTG mRNA following injection of juvenile Arctic char with a single dose of 17beta-estradiol (E2; 10 mg/kg bw). These results indicate that the VEPs have a higher sensitivity for E2 than VTG. However, an early and sex-independent expression of VEPbeta in estrogen-unchallenged juvenile Arctic char was observed. These findings suggests that the regulatory mechanisms of VEPs might be more complex than previously thought, which in turn may have implications for the usage of VEPs as biomarkers for xenoestrogen exposure.

Cloning of rainbow trout egg envelope proteins: members of a unique group of structural proteins.

All vertebrate eggs are surrounded by an extracellular envelope that protects the egg and is vital for a successful fertilization. The terminology and functions of the egg envelope vary in different vertebrate groups, but the envelope itself is consistently composed of a few major proteins that are deposited around the oocyte during oocyte growth. Here, we describe the deduced amino acid sequences and tissue expression patterns of the three major egg envelope proteins for rainbow trout (Oncorhynchus mykiss). All three vitelline envelope proteins (VEPs) are expressed in the livers of both male and female fish, with higher expression in females. In addition, VEPgamma mRNA is also detected in the female gonads. To our knowledge, this is the first time that expression of a VEP protein gene has been demonstrated to occur in more than one organ. Sequence comparison reveals that all three VEP proteins share distinct homology with their amphibian, avian, and mammalian counterparts. Whereas mammalian zona pellucida protein 3 isoforms contain two conserved serines needed for sperm binding, these are not conserved in teleost species, in which sperm entry is restricted to the micropyle. Besides the difference in VEPgamma sperm-binding function, the high sequence homology suggests that the egg envelope proteins from these distinct vertebrate groups share a common ancestry and form a unique group of structural proteins.

Posterior spinal instrumentation and fusion of a neuromuscular scoliosis in a patient with autosomal dominant osteopetrosis.

STUDY DESIGN: A case report of a patient with autosomal dominant osteopetrosis and neuromuscular scoliosis who required surgical instrumentation and fusion of her spine. OBJECTIVE: To illustrate the surgical technique and long-term outcome in this rare form of spinal deformity. SUMMARY OF BACKGROUND DATA: Osteopetrosis is a group of rare skeletal dysplasias characterized clinically by skeletal osteosclerosis that is classically described in appearance as "marble bone." Despite the ubiquitous involvement of the vertebra, clinical manifestations of spinal involvement are uncommon. We present the case of an osteopetrotic patient with neuromuscular scoliosis who required surgical correction of her progressive deformity. There are no prior reports in the literature concerning operative or nonoperative management of scoliosis in this patient population. METHODS: The surgical technique utilized as well as the patient's response to surgical management of her scoliosis is presented with 5 year follow-up. RESULTS: The patient underwent a successful T4 to L1 posterior spine fusion and instrumentation using Luque rods, sublaminar wires and allograft bone augmentation. At 5 years following her index procedure, she is clinically and radiographically fused. CONCLUSION: Patients with osteopetrosis present unique surgical challenges during surgical correction of spinal deformities. The use of segmental sublaminar wires with 1/4-inch rods and crosslinks afforded stable fixation despite poor bone quality. Allograft bone combined with postoperative bracing resulted in a well-maintained correction and a solid fusion. Five year follow-up and continued radiographic evidence of stable fusion indicate that the presented approach can lead to a successful outcome in the osteopetrotic patient population.