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This multicenter clinical study was performed to assess the safety and effectiveness of Trinity Evolution® (TE), a viable cellular bone allograft, in combination with a PEEK interbody spacer and supplemental anterior fixation in patients undergoing anterior cervical discectomy and fusion (ACDF). In a prospective, multi-center study, 31 patients that presented with symptomatic cervical degeneration at one vertebral level underwent ACDF with a PEEK interbody spacer (Orthofix, Inc., Lewisville, TX, USA) and supplemental anterior fixation. In addition all patients had the bone graft substitute, Trinity Evolution (Musculoskeletal Transplant Foundation, Edison, NJ, USA), placed within the interbody spacer. At 6 and 12 months, radiographic fusion was evaluated as determined by independent radiographic review of angular motion (≤4°) from flexion/extension X-rays combined with presence of bridging bone across the adjacent endplates on thin cut CT scans. In addition other metrics were measured including function as assessed by the Neck Disability Index (NDI), and neck and arm pain as assessed by individual Visual Analog Scales (VAS). The fusion rate for patients using a PEEK interbody spacer in combination with TE was 78.6 % at 6 months and 93.5 % at 12 months. When considering high risk factors, 6-month fusion rates for patients that were current or former smokers, diabetic, overweight or obese/extremely obese were 70 % (7/10), 100 % (1/1), 70 % (7/10), and 82 % (9/11), respectively. At 12 months, the fusion rates were 100 % (12/12), 100 % (2/2), 100 % (11/11) and 85 % (11/13), respectively. Neck function, and neck/arm pain were found to significantly improve at both time points. No serious allograft related adverse events occurred and none of the 31 patients had subsequent additional cervical surgeries. Patients undergoing single-level ACDF with TE in combination with a PEEK interbody spacer and supplemental anterior fixation had a high rate of fusion success without serious allograft-related adverse events.

Spinal Trauma

Study design A case study of a previously unreported complication of unsuccessful broken pedicle screw removal in the thoracolumbar spine is presented. Objectives To emphasize an increased awareness of the potential for large vessel injury during difficult broken pedicle screw removal in the thoracolumbar spine and to encourage the thorough evaluation of indications for the removal of any broken distal fragment in a vertebral body. Summary of background data Reported complications of pedicle screw removal include the inability to remove the distal screw fragment, nerve root injury, and dural sheath violation. Damage to anterior vascular structures, including the vena cava, iliac arterial and venous systems, and aorta, has not yet been reported in association with difficult broken pedicle screw removal. Methods An instrument designed to capture the distal end of a screw fragment through an interference fit resulted in inadvertent screw migration into the retroperitoneal space. Plain roentgenograms and computed tomography were used to document this complication, revealing the close proximity of the screw fragment to the aorta. Results Expedient recognition of the anteriorly migrated screw fragment with its subsequent removal resulted in a satisfactory outcome. Conclusion Great care must be taken during the removal of broken pedicle screws to prevent injury to surrounding structures. Additionally, indications for the removal of distal screw fragments must be carefully established. Instruments designed to capture the end of the distal screw fragment through an interference fit may allow anterior screw migration to occur, particularly in osteoporotic bone.

STUDY DESIGN This is a detailed description of a facet-sparing decompression technique and a prospective observational study of 59 subjects. OBJECTIVE To describe a facet-sparing decompression technique, quantify operative parameters, adverse events, and anatomic changes following decompression with a flexible microblade shaving system. SUMMARY OF BACKGROUND DATA Decompression in patients with lumbar spinal stenosis is a common surgical procedure. However, obtaining a thorough decompression while leaving enough tissue to avoid destabilization can be challenging. Decompression with a flexible, through-the-foramen system may mitigate some of these challenges. MATERIALS AND METHODS Fifty-nine subjects diagnosed with lumbar spinal stenosis were recruited into this study. Subjects underwent decompression with a flexible, microblade decompression system at a total of 88 levels between L2 and S1. Subject demographics, details of the procedure, and operation, including adverse events were collected. Preoperative and postoperative computed tomography scans and plain radiographs were obtained from a subset of 12 subjects and quantitatively assessed for bone removal and preservation of stabilizing structures. RESULTS Fifty-nine subjects had 88 levels treated, 51% single-level and 49% 2-level with L4-L5 being the most commonly decompressed level. Operative time, blood loss, and length of stay were similar to or less than that seen in the historical control. The system was successfully used for decompression in 95.8% of the attempted foramina. Three operative complications were reported, all dural tears (5.1%). These dural tears occurred before introduction of the flexible decompression system. Computed tomography scans from 12 subjects demonstrate access to the lateral recess and foramen with removal of

STUDY DESIGN A retrospective chart review of 1561 patients with spinal injury was conducted over a 4-year period. OBJECTIVES To determine the rate of surgical site infection in the spinal trauma population, to compare infection rates after spinal operations for elective and traumatic indications, and to identify risk factors for postoperative wound infections in the traumatic subpopulation. SUMMARY OF BACKGROUND DATA Surgical site infection after spinal operations is a dreaded complication. Risk factors have been investigated previously, but the subset of patients with acute traumatic spinal injury may be distinct. METHODS The hospital's infection control program was used to identify surgical site infections after spinal operations, and infection rates were calculated. Data including patient characteristics, severity of injury indicators, surgical factors, and perioperative management factors were collected for the patients presenting with acute spinal injury over a 4-year period. RESULTS Postoperative wound infections developed in 24 of 256 patients. This infection rate of 9.4% was significantly (P < 0.001) higher than for elective spinal operations during the same period (3.7%). Risk factors found to be independently significant included delay until operation, increased postoperative intensive care unit stay, single (neurosurgical or orthopedic) versus combined operative team. CONCLUSIONS Risk factors for surgical site infection in the acute trauma setting are identified. Two surgical teams may be involved without causing a higher rate of infection.

Symptomatic degenerative disk disease is much less common in the thoracic spine than in the cervical and lumbar regions. Accurate diagnosis relies on a strong clinical suspicion that is confirmed with appropriate diagnostic imaging. Presenting symptoms vary tremendously, from atypical pain patterns to myelopathy. The use of computed tomography in combination with myelography and magnetic resonance imaging have greatly increased the ability to accurately visualize thoracic spine disorders. The superior resolution of available imaging modalities has made the incidental detection of asymptomatic thoracic disk abnormalities more frequent. Most patients with symptomatic thoracic disk disease will respond favorably to nonoperative management. Surgery is indicated for the rare patient with an acute thoracic disk herniation with progressive neurologic deficit (i.e., signs or symptoms of thoracic spinal cord myelopathy). Once surgical intervention has been chosen, careful preoperative planning is necessary. The level, anatomic location, and morphology of the herniation must be precisely determined to select the optimal approach. Posterior laminectomy has largely been abandoned for the treatment of symptomatic thoracic disk protrusions. Surgeons still may choose among anterior, lateral, and posterior approaches when surgically addressing the thoracic intervertebral disk.

Study Design. This study introduces a useful plating technique for complex reconstructions of the anterior cervical spine. Objective. To provide a short-segment-buttressing technique for the stabilization of long anterior fusion constructs in the cervical spine while avoiding the potential morbidity and risks associated with long-segment anterior cervical plating. of Background Data. Anterior fibular or iliac crest strut grafts are at risk of dislodging when used after multisegment (> 3 vertebrael corpectomy in various spinal disorders. Long-segment anterior cervical plates have been used to reduce the incidence of graft displacement and migration but have been shown to increase risk for early failure because of screw dislodgement. Methods. Eleven patients with cervical myelopathy underwent a multilevel (average 3.36 levels) corpectomy followed by the placement of a fibular or iliac crest strut graft. An anterior short-segment locking or Duttress plate was then placed in the vertebral body, either inferior or superior to the seated graft, depending on the ease of insertion and quality of the host bone. Posterior segmental fixation was performed in all patients during the same procedure. The average follow-up was 30.8 months (range, 25-36 months). Results. No incidence of plate or graft migration (anteroposterior plane) or dislodgement was reported in this series. One graft fracture occurred secondary to the placement of a intragraft screw through an anterior functional plate. No patients experienced clinical morbidity related to the junctional plate. Neurovascular complications and wound complications were not encountered in any of these patients. All had an improvement in their neurologic symptoms, and 10 of the 11 patients had fusion documented on plain radiographs. Conclusions. The use of a junctional plate anteriorly along with posterior segmental fixation and fusion may prevent or decrease the incidence of graft and internal fixation dislodgement after a long-segment cervical reconstruction procedure.