✓ With the increasing use of bioabsorbable implants in a variety of clinical conditions, potential advantages in selected spinal applications are now being realized. Newer polymers with biomechanical properties relevant to the requirements of specific spinal implants and resorption rates appropriate for specific spinal applications are being developed. These new materials offer the necessary biomechanical stability of conventional spinal implants without the sequelae associated with metallic implants such as long-term loosening, implant migration, and imaging interference. At this time, the majority of clinical applications for these new polymers have involved tension band plating in the lumbar and anterior cervical spine, anterior spinal interbody reconstruction, posterior bone graft containment, and bone graft harvest site reconstruction.
Alexander R. Vaccaro and Luke Madigan
Pedicle versus lateral mass screws
Alexander R. Vaccaro
Daniel R. Fassett, James S. Harrop and Alexander R. Vaccaro
✓The authors describe a rare case of Brown–Séquard syndrome as a result of indirect, concussive trauma to the spinal cord from a gunshot wound (GSW) and present the magnetic resonance (MR) imaging evidence obtained in this interesting case. The patient was shot in the anterior neck and the bullet passed through the lateral aspect of the C-7 lateral mass and transverse process. Bone fragments from the lateral aspect of C-7 were displaced posteriorly into the soft tissues, but no abnormalities were noted within the spinal canal except for high-intensity signal on T2-weighted MR imaging within the right side of the spinal cord. This is the first reported case to provide MR imaging evidence of a Brown–Séquard spinal cord injury as a result of indirect trauma (concussive injury) from a GSW.
Matthew M. Robbins, Alexander R. Vaccaro and Luke Madigan
The use of bioabsorbable implants in spine surgery is expanding at a rapid pace. These implants are mimicking the roles of traditional metallic devices and are demonstrating similar efficacy in terms of maintaining stability and acting as carriers for grafting substances. Biomechanical studies have demonstrated their ability to stabilize effectively a degenerative cervical and lumbar motion segment. In numerous animal models, researchers have illustrated the ability of bioabsorbable implants to function satisfactorily as an interbody spacer and to achieve satisfactory bone fusion. Investigators have explored various opportunities for these implants to replace their metallic counterparts in clinical studies conducted in humans. The gradual resorption of these implants appears effectively to transfer gradual loads to the grafting substances promoting the biological mechanisms of fusion.
Novel uses of bioabsorbable technology are constantly evolving. Their future as a carrier of biological agents such as bone morphogenetic proteins and bone graft extenders, their radiolucency, and their eventual resorption make them an ideal implant for use in spinal degenerative disease.
Pascal Jabbour, Michael Fehlings, Alexander R. Vaccaro and James S. Harrop
In this paper the authors review spine trauma and spinal cord injury (SCI) in the geriatric population. The information in this study was compiled through a literature review of clinical presentation and management of SCI in the elderly population. This was done to define, identify, and specify treatment algorithms and management strategies in this unique patient population.
Christopher Ames, Vincent C. Traynelis and Alexander R. Vaccaro
Gregory J. Przybylski, James S. Harrop and Alexander R. Vaccaro
Acute respiratory failure has been observed in patients after external immobilization for displaced odontoid fractures. The authors studied the frequency of respiratory deterioration in the acute management of displaced Type II odontoid fractures to identify patients at risk for respiratory failure.
The authors conducted a retrospective review of a consecutive series of 89 patients with odontoid fractures who were treated over a 5-year period to identify 53 patients with displaced Type II odontoid fractures. Patient demographics, degree of displacement, respiratory status, treatment method, and outcome were examined. Of the 32 patients with posteriorly displaced fractures, 13 experienced acute respiratory compromise, whereas only one of 21 patients with anteriorly displaced fractures had respiratory difficulties (p = 0.0032). The average posterior displacement was 6.9 mm. All 13 were initially managed using flexion traction for reduction of these fractures. Two of these patients died because of failure to emergently secure an airway during closed treatment of the fracture.
Frequent respiratory deterioration during acute closed reduction of posteriorly displaced Type II odontoid fractures was observed, whereas respiratory failure in patients with anteriorly displaced fractures was rare. The use of the flexed cervical position in the setting of retropharyngeal edema rather than the direction of the displacement may substantially increase the risk of respiratory failure. This may prompt early elective nasotracheal intubation during closed reduction of posteriorly displaced Type II odontoid fractures that require a flexed posture.
Harvey E. Smith, David W. Wimberley and Alexander R. Vaccaro
Discectomy, decompression, and fusion are traditionally used to manage cervical disc disease accompanied by neural element compression that is refractory to conservative management. Concerns regarding stress at levels adjacent to fusion and possible adjacent-level degeneration as well as a desire to maintain a more normal biomechanical environment have led to investigation of cervical disc replacement as an alternative to fusion procedures. Cervical disc prostheses currently under investigation are constructed of predominantly metal-on-polyethylene or metal-on-metal bearing surfaces, and use roughened titanium surfaces and osteoconductive coatings to facilitate fixation. The unique anatomy and biomechanics of the cervical spine must be considered when extrapolating from the experience of appendicular arthroplasty and lumbar disc replacement.
Alexander R. Vaccaro, Matthew M. Robbins, Luke Madigan, Todd J. Albert, William Smith and Alan S. Hilibrand
In this pilot study the authors assessed the efficacy of bioabsorbable interbody spacers in the treatment of cervical degenerative disease. Metallic cages or interbody spacers have been widely used in the treatment of degenerative and traumatic cervical disease. Bioabsorbable technology has been used to develop a resorbable cage that can eliminate the complications and drawbacks seen with the use of traditional metallic implants. In general clinical practice bioabsorbable implants have shown the ability to degrade safely while demonstrating optimal imaging characteristics as a result of their radiolucency, and these devices eliminate stress shielding by their gradual dissolution.
This study is a retrospective evaluation of charts and x-ray films obtained in the first eight patients who underwent an anterior cervical decompression and fusion procedure with placement of a bioabsorbable interbody spacer and anterior cervical plate. All patients were treated in one surgeon's practice and had a minimum follow-up period of at least 6 months. At a follow-up interval of approximately 7 months, five patients exhibited an excellent result and three had a good result; no patient was noted to have a satisfactory or poor outcome according to the Odom criteria at their most recent follow-up visit. Seventeen (94%) of 18 grafted levels appeared to be solidly fused. One patient experienced a perisurgical complication consisting of a symptomatic hematoma, which was successfully drained.
Bioabsorbable interbody spacers appear to be a safe and effective interbody implant in terms of clinical outcome and radiographically confirmed healing.
James S. Harrop, Ashwini D. Sharan, Edward H. Scheid Jr., Alexander R. Vaccaro and Gregory J. Przybylski
Object. The authors sought to identify variables that predispose patients with acute American Spinal Injury Association (ASIA) Grade A cervical spinal cord injury (SCI) to require tracheostomies for ventilator support or airway protection.
Methods. A retrospective analysis was performed of 178 consecutive patients with a cervical ASIA Grade A SCI who were admitted through the Delaware Valley SCI Center at Thomas Jefferson Hospital during a 6-year period. Exclusion criteria included injury occurring more than 48 hours prior to admission, death within 14 days of admission or nontraumatic SCI. Twenty-two patients were excluded based on these criteria. Parameters evaluated in the remaining population (156 patients) included demographics, cervical vertebral ASIA level, tracheostomy placement, pneumonia, premorbid pulmonary disease, smoking history, evidence of direct thoracic/lung trauma, operative intervention, associated appendicular trauma, and preexisting medical comorbidities.
The ASIA classification of the 156 patients included in this analysis were C-2 (eight), C-3 (11), C-4 (64), C-5 (36), C-6 (20), C-7 (13), and C-8 (four). Tracheostomies were performed in 107 of these 156 patients. Statistical analysis revealed a significant relationship between tracheostomy and patient age (p = 0.0048), preexisting medical conditions (p = 0.0417), premorbid lung disease (p = 0.0177), higher cervical ASIA level (p < 0.0001), and the presence of pneumonia (p < 0.0001). No patient with a C-8 ASIA A injury required tracheostomy, whereas all C-2 and C-3 ASIA A—injured patients underwent tracheostomies. Patients older than 45 years of age with ASIA A levels between C-4 and C-7 more commonly required tracheostomy (p < 0.005) than patients younger than 45 years of age.
Conclusions. Several risk factors were identified that corresponded to the frequent tracheostomy placement in the acute injury phase after complete cervical SCI. Early tracheostomy may be considered in patients with multiple risk factors to reduce duration of stay in the intensive care unit and facilitate ventilatory weaning.