SPINE PAPERS

Table 1. PSF Group

Collar Group

PAPER NO. 76

Mortality

20% (5/25)

12.5% (4/33)

Functional and Radiographic Outcomes of Geriatric Odontoid Fractures Treated with Rigid Collar or Posterior Fusion

Complications

24% (6/25)

6% (2/33)

Fracture Healing

28% (7/25)

6% (2/33)

Mobile Nonunion

0%

67% (20/30)

William J. Molinari, III, MD, Rochester, NY Oner Khera, MD, Glendale, AZ William Gruhn, PA-C, Rochester, NY Robert W. Molinari, MD, Pittsford, NY INTRODUCTION: Controversy exists as to the most effective management option for elderly patients with type II odontoid fractures. Furthermore, outcomes for those patients who do not achieve fusion or fracture healing after treatment remain unclear in the literature. The purpose of this study is to evaluate fracture healing rates, functional outcomes, complications, and mortality associated with rigid cervical collar and posterior fusion surgery for the management of geriatric type II odontoid fractures. METHODS: Fifty-eight consecutive elderly patients with type II odontoid fractures were treated by the same fellowship-trained spinal surgeon at a level 1 trauma center during an eight-year period. Patients with greater than 50% odontoid displacement were treated with posterior fusion surgery including C1-2 (PSF Group, n= 25, Ave age = 80 yrs). Patients with less than 50% odontoid displacement were treated with a rigid cervical collar for 12 weeks (Collar Group, n=33, Ave age = 83 yrs). Chart reviews were performed evaluating patient comorbidities, treatment complications, and mortality rates. At the time of ultimate follow up, patients had open mouth, flexion and extension radiographs to assess fracture stability and healing. Additionally, functional outcomes were assessed using Neck Disability Index (NDI), analog pain and satisfaction questionnaire scores. RESULTS: At average 14 month follow up (range 3-48 months), fracture healing rates were higher in the operative group (28% vs 6%). A total of 64% of the nonoperative patients had mobile nonunion versus 0% in the operative group. The average mobility of the nonunion was 2.5mm (range 1-12mm). NDI scores were lower in the nonoperative group (13 vs. 18.3) indicating a trend toward less disability in the nonoperative group (p=0.23). There was also a trend toward lower analog pain scores in the nonoperative group (1.3 vs. 1.9, p=0.26). Satisfaction scores were equally high in both groups (9.1 vs. 8.9). Mobile odontoid nonunion was not associated with higher levels of disability or neck pain, and did not affect scores for patient satisfaction. Mortality rate was 12.5% in the C-collar group and 20% in the operative group. Complications were higher in the operative group (24% vs 6%) (Table 1, Figure 1). DISCUSSION AND CONCLUSION: Rates of type II odontoid facture healing and stability appear to be higher in geriatric patients treated with posterior fusion surgery. Fracture healing and stability did not correlate with improved outcomes with respect to levels of pain, function and satisfaction. Mortality and complication rates are lower in those patients who are treated with a cervical collar and early mobilization.

951

PAPER NO. 77

Reoperation Following Degenerative Spondylolisthesis Surgery: A Subgroup Analysis of the SPORT Edward P. Curry, MD, Philadelphia, PA Kristen E. Radcliff, MD, Margate City, NJ Alan S. Hilibrand, MD, Philadelphia, PA Jeffrey A. Rihn, MD, Media, PA Todd J. Albert, MD, Philadelphia, PA Wenyan Zhao, PhD, Hanover, NH Jon Lurie, MD, Lebanon, NH James N. Weinstein, DO, Lebanon, NH INTRODUCTION: Several factors are known to influence the outcome of surgery of degenerative spondylolisthesis. However, less is known about the predictors of reoperation. The SPORT trial is a prospective, multicenter study of surgical treatment versus nonoperative treatment for lumbar conditions. The hypothesis of study is that there would be significant baseline differences between patients who underwent reoperation and patients who did not undergo reoperation for degenerative spondylolisthesis. Such data might be helpful in identifying patients at risk for developing additional problems at other levels METHODS: This is a subgroup analysis of patients enrolled in SPORT for treatment of degenerative spondylolisthesis with randomized and observational cohorts. The degenerative spondylolisthesis patients were divided according to reoperation (n=58) or no reoperation (n=333). Change in primary and secondary outcome measures and treatment effect of surgery were assessed at baseline, one year, two years, three years, and four years. RESULTS: At baseline, there were no significant differences between reoperation and no reoperation patients in demographic characteristics, clinical outcome scores, body mass index. The

u The FDA has not cleared the drug and/or medical device for the use described in this presentation (i.e. the drug or medical device is being discussed for an off label use). For full information refer to page 14. An alphabetical faculty financial disclosure list can be found starting on page 19.

PAPERS, POSTERS & SCIENTIFIC EXHIBITS SPINE

reoperation patients had a significantly lower likelihood of having pseudoclaudication (74% vs. 88%, p=0.007) or asymmetric depressed reflexes (12% vs. 28%, p=0.015). There was no difference between reoperation and no-reoperation patients in type of procedure, levels of fusion, decompression level, or number of levels decompressed. There was a significantly increased percentage of complications of the index surgery in the reoperation patients. By the final four year follow up, there was no significant difference between reoperation and no reoperation groups in SF36 BP, SF36 PF, SF36 PCS, SF36 MCS, ODI, Sciatica Bothersomeness Index, Low Back Bothersomeness, Percent Satisfaction, Leg Pain Bothersomeness Index. The most common reasons for reoperation were recurrent stenosis/progressive spondylolisthesis (5%), new condition (2.4%), infection (2.4%), pseudoarthrosis/fusion exploration (1.1%). The overall rate of reoperation at four years was 14.8% for patients with degenerative spondylolisthesis in the SPORT. DISCUSSION AND CONCLUSION: The overall incidence of reoperation at four years was 14.8% for degenerative spondylolisthesis. Type of fusion, number of levels addressed, and instrumentation were not associated with a change in incidence of reoperation in patients with degenerative spondylolisthesis. Preoperative symptoms of pseudoclaudication and asymmetric depressed reflexes were associated with reduced risk of reoperation for degenerative spondylolisthesis. There was no significant difference in the outcome of patients who underwent reoperation for degenerative spondylolisthesis versus patients who did not undergo reoperation.

PAPER NO. 78

The Limited Benefit of Coronal Cobb Angle Correction in the Setting of Adult Spinal Deformity Virginie Lafage, PhD, New York, NY Frank J. Schwab, MD, New York, NY Benjamin Blondel, MD, New York, NY Justin S. Smith, MD, Charlottesville, VA Jason Demakakos Keith H. Bridwell, MD, Saint Louis, MO Steven D. Glassman, MD, Louisville, KY Christopher I. Shaffrey, MD, Charlottesville, VA INTRODUCTION: Adult spinal deformity (ASD) can cause pain and disability due to global malalignment. The extent of coronal plane deformity correction needed for clinical benefit remains controversial but Cobb angle has been described as a key parameter for evaluation of ASD patients. The aim of this study was to evaluate the amount of Cobb angle correction needed to achieve incremental clinical benefit and likelihood of reaching minimal clinically important difference (MCID) using health related quality of life (HRQL) scores. METHODS: Baseline and two year radiographic and HRQL data (ODI, SRS-22r and SF-12) were retrospectively analyzed for patients consecutively enrolled in a multi-center, prospective ASD database. Patients were divided into three groups based on postoperative Cobb angle improvement: 35°. Pre and post-op results for each group and changes in HRQL scores for each improvement subdivision were analyzed using paired t-test and one-way ANOVA. RESULTS: Sixty patients with thoraco-lumbar or lumbar curve >50° were included. A significant improvement for HRQOL scores was found between pre-op and last follow up data across the study population (p 70 years

ASA

0.14

0.13

> 3rd group

Ambulatory status

0.087

0.19

>= 3rd group

BMI

0.060

0.082

< 18.5

PAPER NO. 80

The Fate of Asymptomatic Cervical Stenosis: A Prospective Cohort Study K. D. Riew, MD, Saint Louis, MO Michael P. Kelly, MD, St Louis, MO Moon Soo Park, MD, Anyang-Si, Republic of Korea Carie R. Kennedy, BS, RN, St Louis, MO INTRODUCTION: The natural history of asymptomatic patients who have cervical stenosis is not well-defined and the treatment of such patients remains controversial. As a result, there is variability in treatment recommendations for such patients. Some surgeons favor prophylactic decompression in order to prevent a catastrophic neurological injury, while others favor observation. Unfortunately, there are few long-term natural history studies that can provide a scientific rationale for treatment of such individuals. METHODS: We prospectively enrolled adult patients with spinal canal AP diameter measuring < 9mm on an MRI with no cord signal, no symptoms of myelopathy who were willing to participate in a long-term study with an endpoint of surgical intervention or neurologic injury. Exclusion criteria: Age over 80 years, pathologic or traumatic compression, instability requiring stabilization. Enrolled patients were recommended to have repeat physical exams and MRIs annually. Anyone who developed myelopathy, cord signal change or recalcitrant radiculopathy had operative intervention. Our null hypothesis is that a high percentage of asymptomatic persons with a spinal canal size ≤9 mm per MRI will become paralyzed or need operative intervention within a short period of time. RESULTS: We enrolled 73 patients. The space available for the spinal cord was between 3-9 mm. Follow up was between 1-12 years (mean 3.7 years; cumulative follow-up of 218.3 patientyears), with 48 patients having a minimum two-year followup (mean 4.6 years, 197.8 patient-years follow up). No patient became para or tetraplegic. The cumulative follow up of these patients represents 218.3 patient-years without irreversible neurologic deterioration. Only eight patients eventually required surgery (one arthroplasty, two laminaplasties, five anterior corpectomy/discectomies). Of these, three had myelopathy, two myeloradiculopathy and three radiculopathy. DISCUSSION AND CONCLUSION: Few prospective natural history studies with long-term follow up regarding the cervical spine exist. To our knowledge, this is the largest prospective 953

study with the longest follow up regarding the natural history of patients with cervical spinal stenosis without cord signal change or myelopathy. With over 218 patient-years of follow up, no one suffered a catastrophic neurologic event or even a minor neurologic deficit. This suggests that such events are relatively rare and that most patients can be managed safely with repeat exams, MRIs and education regarding the signs and symptoms of myelopathy. However, further follow up is needed to determine if such a regimen is safe long-term.

PAPER NO. 81

Do Epidural Steroid Injections Affect Outcomes for Lumbar Stenosis and Degenerative Spondylolisthesis Patients? Kristen E. Radcliff, MD, Margate City, NJ Christopher Kepler, MD, Philadelphia, PA Alan S. Hilibrand, MD, Philadelphia, PA Wenyan Zhao, PhD, Hanover, NH Jonathan Lurie, MD, Lebanon, NH Jeffrey A. Rihn, MD, Media, PA Todd J. Albert, MD, Philadelphia, PA James N. Weinstein, DO, Lebanon, NH INTRODUCTION: The SPORT trial is a prospective, multicenter study of surgical treatment versus nonoperative treatment for lumbar stenosis and degenerative spondylolisthesis. The hypothesis of this subgroup analysis was that patients who received epidural steroid injections (ESI) during treatment would have improved outcome and a lower rate of crossover to surgery compared to patients who did not receive ESI. METHODS: The study population includes patients enrolled in SPORT for treatment of spinal stenosis or degenerative spondylolisthesis who did not receive ESI prior to enrollment in the study. Patients who received epidural steroid injections during the first three months of the study were compared to patients who did not receive epidural injections during the first three months of the study (No ESI). Change in primary and secondary outcome measures and treatment effect of surgery were assessed at baseline, one year, two years, three years, and four years. RESULTS: In the spinal stenosis cohort, there were 69 ESI patients and 207 No-ESI patients. There were no significant differences in demographic factors, baseline clinical outcome scores, or operative details but there was an increased preference for nonsurgical treatment among the ESI patients (p