9:31 158. Non-Neurologic Complications Following Surgery for Adolescent Idiopathic Scoliosis

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Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S

Fig. 1.

while still liquid using a minimally invasive procedure. The device cures to a firm, but pliable form within minutes. The DASCOR device received CE Mark approval in July 2005, and a postmarket study is currently underway. PURPOSE: To evaluate the 2-year safety and effectiveness of the DASCOR device in patients. STUDY DESIGN/SETTING: An ongoing multicenter prospective, nonrandomized, European clinical study. PATIENT SAMPLE: Eligible patients between February 2003 and August 2005 were followed for up to 2 years. Inclusion criteria included mild to moderate single-level DDD with concordant provocation discography, significant back pain (at least 5 and 40 on the respective Visual Analog [VAS] and Oswestry scales), 6-month failed nonoperative care, and no prior fusion surgery. OUTCOME MEASURES: VAS and Oswestry scores, radiographic assessments, and analgesic medication use (a 3-point scale). METHODS: A standardized retroperitoneal mini ALIF or ALPA was used to perform a total nucleus removal and implant the DASCOR device. Outcome measures were all collected preoperatively and were postoperatively followed at multiple intervals throughout the 2 years. Clinical success was defined as a 2 and 15 point decrease in the respective VAS and Oswestry scores. RESULTS: To date, 22 patients (9 female, 13 male) with a mean age of 39.1 years were implanted at the L5/S1 (n514) or L4/5 (n58) levels with 97% of expected patient visits completed. Mean operating time was 87.2 minutes, and average blood loss was 53.0 cc. Mean preoperative VAS and Oswestry scores improved dramatically after 6 weeks postoperatively and throughout the 2-year follow-up period (Fig. 1). Generally, analgesic medication use decreased dramatically over time with all patients experiencing significant improvements after 3 months. The analgesic medication use score of patients at the 2-year follow-up was almost zero. MRI evaluations showed no significant Modic changes, bone edema, subsidence, or device migration. Finally, radiographic assessments showed preservation of disc height and range of motion. CONCLUSIONS: The 2-year clinical experience of the DASCOR device demonstrated high clinical success and safety based on the significant postoperative pain reduction, functional improvement, and a low complication rate. Postoperative improvements at 6 weeks were preserved if not improved throughout the 2-year follow-up period even when analgesic medication decreased with time. The use of a standardized minimally invasive surgical technique proved reliable and safe with a low complication rate. The concept of total nucleus removal required for a successful DASCOR device implantation proved clinically reliable as the device conformed to the nuclectomy space as confirmed in postoperative MRI. FDA DEVICE/DRUG STATUS: DASCOR Device: Investigational/not approved. CONFLICT OF INTEREST: Author (HY) Board Member: Disc Dynamics Inc.; Authors (HY, JS) Stockholder: Disc Dynamics Inc.; Author (MA)

Grant/Research Support: Disc Dynamics Inc. Research grant RG2001; Author (AT) Employee: Disc Dynamics Inc. doi: 10.1016/j.spinee.2006.06.204

Saturday, September 30, 2006 9:31–10:14 AM Concurrent Session 2: Deformity 9:31 158. Non-Neurologic Complications Following Surgery for Adolescent Idiopathic Scoliosis Rolando Puno, MD1, Lawrence Lenke, MD2, Stephen Richards, MD3, Daniel Sucato4, John Emans, MD5, Mark Erickson, MD6; 1Leatherman Spine Center, Louisville, KY, USA; 2Washington University in St. Louis, Saint Louis, MO, USA; 3TX, USA; 4Texas Scottish Rite Hospital for Children, Dallas, TX, USA; 5Children’s Hospital, Boston, MA, USA; 6 Children’s Hospital, Denver, CO, USA BACKGROUND CONTEXT: Corrective surgery on a healthy child with scoliosis is still considered a major undertaking. Reported incidences of non-neurologic complications are low but vary. However, most reports were based on retrospective reviews of patients for the purpose of evaluating treatment and not solely focused on complications. PURPOSE: To determine the incidence of non-neurologic complications in a large patient population with prospectively collected data. STUDY DESIGN/SETTING: Prospective multi-center cohort study. PATIENT SAMPLE: This study evaluated 702 patients with complete data points from 734 patients who underwent corrective surgery for adolescent idiopathic scoliosis and were enrolled a multi-center database. OUTCOME MEASURES: Incidence of non-neurologic complications. METHODS: Demographics, surgical history, and incidence of non-neurologic complications in a prospective multi-center study of adolescent idiopathic scoliosis were reviewed. Non-neurological complications were divided into those that occurred perioperatively (first 7 days postoperatively), early (within the first month), and late (those that occurred after 1 month). The variables analyzed include body mass index, presence of cardiac, respiratory, and renal disease, previous surgery, pulmonary function, surgical approach, numbers of levels fused, blood loss, surgical time, anesthesia time, type of graft material, diaphragmatic incision, Lenke curve type, and region of major curve. RESULTS: There were 556 females and 147 males. The mean age at the time of surgery was 14.25 years (range: 7–18 years). 523 patients had

Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S a posterior only procedure, 105 had an anterior only procedure, and 74 had an anterior/posterior procedure. There was a total of 116 complications in 84 patients giving an overall incidence of 16%. There were 43 perioperative complications in 41 patients, 52 early complications in 47 patients, and 21 late complications in 17 patients. There were 4 (0.5%) early infections, 25 (3.6%) operative complications, 13 (1.7%) respiratory complications, 3 (0.4%) superior mesenteric syndrome, 3 (0.4%) urinary complications, and 68 (6.6%) other complications. Five patients required re-operations. Two were for early infections and three for late implant failures. Factors that did not correlate with an increased incidence of complications were body mass index, presence of cardiac or respiratory disease, previous surgery, pulmonary function, surgical approach, numbers of levels fused, type of graft material, diaphragmatic incision, Lenke curve type, and region of major curve. Patients with a history of renal disease were 7.9 times more likely to suffer a non-neurologic complication than other patients. Smaller proximal thoracic curves were associated with non-neurologic complications, but there was no relationship between thoracic or thoracolumbar curve magnitude and non-neurologic complications. Increased operative blood loss, prolonged posterior operative time, and anesthesia time were associated with higher incidences of non-neurologic complications in the perioperative period. Prolonged anesthesia time was also associated with a higher incidence of late non-neurologic complications. CONCLUSIONS: The incidence of non-neurologic postoperative complications following corrective surgery for adolescent idiopathic scoliosis appears to be relatively low. The few factors noted to significantly increase the rate of complications include history of renal disease, increased operative blood loss, prolonged posterior surgery time, and anesthesia time. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: Author (RP) Consultant: Medtronic Sofamor Danek; Author (RP) Royalties: Medtronic Sofamor Danek; Authors (RP, LL, SR, DS, JE, ME) Grant/Research Support: Medtronic Sofamor Danek. doi: 10.1016/j.spinee.2006.06.195

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26.1622.1 years developed a postoperative wound infection requiring a debridement in the operating room, for an overall infection rate of 2.6%. The overall infection rate was 2.1% (39/1897) in pediatric patients (less than 18 years of age) and 3.7% (36/979) in adult patients (18 years of age or greater). The risk of developing a postoperative wound infection was in large part determined by the patient’s underlying diagnosis as is illustrated in Table 1. Table 1 Overall infection rate stratified by underlying diagnosis Diagnosis Neuromuscular Scoliosis Congenital Kyphosis/Scoliosis/ kyphoscoliosis Adolescent Idiopathic Scoliosis Degenerative Scoliosis Adult Idiopathic Scoliosis Fixed Sagittal Im balance Trauma Charcol Spine Kyphosis Infantile Scoliosis Scheuermann’s Disease Other Total

Patients w/Infection

Total Patients

Infection Rate

18 11

495 272

3.6 4.0

10

1031

1.0

8 6 5 4 3 1 1 1 7 75

81 369 71 64 9 126 23 54 281 2876

9.9 1.6 7.0 6.3 33.3 0.8 4.3 1.9 2.5 2.6

CONCLUSIONS: A postoperative wound infection can be a devastating complication; fortunately, however, the risk of developing a wound infection after spinal deformity surgery is reasonably low and varies considerably depending on the patient’s underlying diagnosis. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2006.06.196

9:37 159. Infections in Spinal Deformity Surgery: A Fifteen-Year Review Jacob Buchowski, MD, MS1, Ronald Lehman, Jr., MD2, Craig Kuhns, MD1, Keith Bridwell, MD1, Lawrence Lenke, MD1; 1Washington University in St. Louis, St. Louis, MO, USA; 2Walter Reed Army Medical Center, Washington, DC, USA BACKGROUND CONTEXT: Spinal deformity surgery is technically demanding and can be fraught with complications. Currently, there are no studies focusing on infections after deformity surgery in the peer-reviewed literature. PURPOSE: The objectives of this study were to evaluate postoperative infections in adult and pediatric patients undergoing spinal deformity surgery, to determine risk factors for developing a postoperative wound infection, to examine treatment strategies, and to analyze patient outcome. STUDY DESIGN/SETTING: A retrospective cohort study. PATIENT SAMPLE: Adult and pediatric patients who underwent spinal deformity surgery (5 levels or more) at a single tertiary referral spine center over a 15-year period (1990–2005) and developed a postoperative wound infection requiring a formal debridement in the operating room. OUTCOME MEASURES: Clinical outcome measures. METHODS: A total of 2876 patients underwent deformity surgery at our institution during the study period. The medical records of these patients, including operative and clinic notes, as well as laboratory and microbiology reports were reviewed. RESULTS: Of the 2876 patients who were treated surgically for spinal deformity, 75 patients (45 females and 30 males) with an average age of

9:43 160. Adjacent Segment Degeneration Following Lumbar/ Thoracolumbar Fusion With Pedicle Screw Instrumentation: A Minimum 5-Year Follow-Up Gene Cheh, MD, Keith Bridwell, MD, Lawrence Lenke, MD, Yongjung Kim, MD, Michael Daubs, MD, Christine Baldus, RN; Washington University in St. Louis, St. Louis, MO, USA BACKGROUND CONTEXT: Adjacent segment degeneration (ASD) is a known side effect of spinal fusion. Previous studies have shown the risk factors of developing ASD to be multifactorial. There are conflicting reports on the effect of the number of fused segments on the development of ASD. PURPOSE: To determine the effect of length of fusion on the development of ASD. STUDY DESIGN/SETTING: A retrospective study. PATIENT SAMPLE: 75 patients with a minimum 5-year follow-up who had a single or multi-level lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative disorders were included. Patients who had hybrid construct or implant other than pedicle screws were excluded. OUTCOME MEASURES: Outcomes were measured by radiological determination of ASD and patients’ global clinical assessment. METHODS: Radiographs were analyzed with regard to degeneration at the adjacent levels preoperatively and postoperatively. Radiographic ASD was defined either by: 1) development of a spondylolisthesis; or 2) loss of sagittal angulation O10  ; or 3) more than 2 grade worsening in