P97. A Prospective Randomized Comparison of Cervical Disc Replacement and Anterior Cervical Fusion

Proceedings of the NASS 23rd Annual Meeting / The Spine Journal 8 (2008) 1S–191S refractory to non-operative treatment. (1,2,3). With the evolution of minimally invasive spine (MIS) surgery, a group of techniques, such as unilateral MIS transforaminal lumbar interbody fusion (TLIF) and percutaneous pedicle screw fixation were developed to preserve much of the normal archetecture of the spine. (4, 5, 6, 7, 8, 9, 10). We present in this paper long term clinical outcome in a large series of patients suffering from chronic debilitating back pain using this technique. PURPOSE: To report long term outcome results in a large series of patients undergoing MIS TLIF fusion and instrumentation. STUDY DESIGN/ SETTING: Retrospective cohort of patients. PATIENT SAMPLE: 105 patients suffering from chronic debilitating back pain refractory to non-operative treatment. OUTCOME MEASURES: Neurological Status, magnetic resonance imaging (MRI), computer tomography (CT), plain dynamic radiograph analysis, Visual Analog Scale (VAS), and Oswestry Disability Index (ODI) outcome scores. METHODS: A group of 105 patients underwent MIS TLIF and percutaneous pedicle screw placement by the senior author. Patient characteristics included 41 men (39%) and 64 women (61%) with an average age of 56 years (range 32 to 85 years). Clinical diagnosis at the treatment level consistented of DDD in 40 patients (38%), spondylolisthesis in 50 patients (48%) and a combination in 15 patients (14%). Average duration of symptoms was 49 months with 26 patients (25%) having undergone prior lumbar surgical procedure(s). Outcome variables measured included neurological status, radiographic analysis, VAS, ODI preoperative, 2 weeks, 2 weeks-3 months, 3, 6, 9, 12, 24 months. Statistical methods included T-Student and square Chi for univariate analysis. RESULTS: The levels of MIS fusion included 55 patients at L4/L5 (52%), 38 patients at L5/S1 (29%), 6 patients at L2/L3 (6%) and 6 patients at L3/ L4 (6%). An average of 180 cc of blood loss was noted and an average hospital stay of 2.96 days. Neurological status was better in 90 patients (86%), same in 12 patients (11%), and worse in 3 (3%). ODI score showed a progressive decline in the disability index from 50 preoperative status to 30 at 6 months and 29 at 1 year with 41.5% of improvement (p 0.003). VAS showed a reduction from an average of 7.12 at the preoperative state to 2.92 at 1 year (59% of reduction of pain). No patients had worsening of neurological deficit. One morbidly obese patient was return to the operating room (OR) for interbody graft failure and two for repositioning of interbody graft. One person returned to OR for hardware removal secondary to irritation. Dynamic plain radiographic assessment revealed pseudoarthrosis in two patients (1.9%). CONCLUSIONS: The combination of results points towards a good to excellent outcomes in the majority of patients with a recovery of premorbid work status (p 0.003). MIS TLIF and percutaneous pedicle screw fixation is an effective and safe treatment for patients suffering from refractory chronic debilitating back pain. Surgical outcomes with TLIF procedures 2 PREOPERATIVE WEEKS OSWESTRY 49.6 VAS 7.12

43.15 4.59

3 MONTHS

6 MONTHS

9 MONTHS

12 MONTHS

24 MONTHS

45.9 4.38

30.14 3.72

31.69 1.39

29.05 2.92

30 3.85

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.340

P96. The Short-term and Long-term Consequences of Aggressive vs. Conservative Discectomy for the Treament of Lumbar HNP with Radiculopathy: An Evidence Based Literature Review William Watters, III, MD; Baylor College of Medicine, Houston, TX, USA BACKGROUND CONTEXT: It remains unknown whether ‘‘aggressive’’ disc removal with curettage versus ‘‘conservative’’ removal of disc

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fragment with little disc invasion provides better short-term and/or longterm outcomes for the surgical treatment of lumbar disc herniation with radiculopathy. PURPOSE: Determine the level of evidence within the literature that supports the performance of a conservative versus aggressive technique for discectomy. STUDY DESIGN/ SETTING: Systematic evidence-based review of literature. PATIENT SAMPLE: Patients reported in the spinal literature with primary lumbar disc herniation and radiculopathy who failed non-operative care and proceeded onto surgical intervention. Patients receiving percutaneous, disc ablative procedures were not included in the patient sample. OUTCOME MEASURES: Operative time, return to work status, recurrent disc herniation, self-reported and functional outcomes measures assessed !2 years (short-term) and O2 years (long-term) after surgery. METHODS: Systematic Medline search was used to identify all published studies relating to outcome after aggressive or conservative discectomy. Levels of evidence (I-V) were assessed for each study and grades of recommendation were generated (Good, Fair, Poor, Insufficient evidence) based on the NASS Clinical Guidelines’ Levels of Evidence and Strength of Recommendation criteria. RESULTS: There is fair evidence that conservative discectomy will result in shorter operative times and a quicker return to work despite similar length of hospital stay, similar pain level at discharge, similar 6-month functional status, and a similar 2-year incidence of persistent/recurrent back and leg pain. There is poor quality evidence that conservative discectomy will result in a lower incidence of recurrent back pain beyond 2-years postoperatively. There is fair quality evidence that conservative discectomy will result in a higher incidence of recurrent disc herniation. CONCLUSIONS: There are no level I studies to support conservative over aggressive discectomy for the treatment of primary disc herniation. However, systematic review of the literature suggests that conservative discectomy may result in shorter operative time, quicker return to work, and a decreased incidence of long-term recurrent low back pain. Conserviative discectomy, however, appears to result in an increased incidence of recurrent disc herniation. Prospective randomized trails are needed to firmly assess this possible benefits and limitatins of conservative discectomy. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.341

P97. A Prospective Randomized Comparison of Cervical Disc Replacement and Anterior Cervical Fusion Scott Blumenthal, MD1, Jack Zigler, MD1, Richard D. Guyer, MD1, Amy Waldrip, PhD2, Donna Ohnmeiss, PhD2; 1Texas Back Institute, Plano, TX, USA; 2Texas Back Institute Research Foundation, Plano, TX, USA BACKGROUND CONTEXT: In the past anterior cervical fusion (ACF) has been the ‘‘gold standard’’ for treating painful cervical disc(s). In more recent years, cervical total disc replacement (TDR) has become a popular procedure for treating this condition. PURPOSE: The purpose of this study was to compare one center’s experience with prospective studies comparing cervical TDR to ACF. STUDY DESIGN/ SETTING: The data were collected from three prospective randomized studies comparing cervical TDR to ACF performed at a single site. PATIENT SAMPLE: A total of 40 patients were randomly assigned to TDR (n515) or ACF (n525) have reached 12-month follow-up. All patients were treated for disc degeneration unresponsive to non-operative care. OUTCOME MEASURES: The Neck Disability Index (NDI) was used to assess functional disability in all of the studies.

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Proceedings of the NASS 23rd Annual Meeting / The Spine Journal 8 (2008) 1S–191S

METHODS: Data from the individual studies were combined into a single database. The inclusion and exclusion criteria for the studies were very similar. All patients completed the NDI before surgery as well as multiple follow-up periods including 12-month. RESULTS: The TDR group and fusion group did not differ significantly on demographics. The two groups did not differ significantly on operative time (TDR 82.2 min vs. ACF 80.8 min). NDI scores were not statistically different in the two groups pre-op or any follow-up periods (Figure). NDI scores did improve significantly by 6 weeks and remained improved throughout the 12-month follow-up. Adverse events in the two groups were similar.

The mean NDI scores were similar pre-op and improved significantly (p!0.01) at 6 wk and were maintained through 12-months. There were no significant differences between ACF and TDR groups at any of the assessment periods. CONCLUSIONS: The results of this study indicated that cervical TDR and ACF produce similar results. Both groups improved significantly early (6 wks) and maintained improvement through 12-month follow-up. These patients continue to be followed, but based on the results of this study, cervical TDR may be a viable alternative to ACF. FDA DEVICE/DRUG STATUS: ProDisc-C: Approved for this indication; Mobi-C: Investigational/Not approved; KineflexjC: Investigational/ Not approved. doi:10.1016/j.spinee.2008.06.342

P98. Can Posterior-only Surgery Replace Combined Anterior Thoracotomy-Thoracoabdominal-Posterior Approaches for Adult Scoliosis? Christopher Good, MD, Lawrence Lenke, MD, Patrick O’Leary, MD, Mark Pichelmann, MD, Kathryn Keeler, MD, Keith Bridwell, MD, Christine Baldus, RN, MHS, Linda Koester; Washington University in St. Louis, St. Louis, MO, USA BACKGROUND CONTEXT: Combined anterior/posterior (A/P) fusion has traditionally been used to treat severe adult scoliosis deformities. Anterior thoracotomy/thoracoabdominal approaches negatively impact pulmonary function and may require additional operative time and anesthesia. PURPOSE: To evaluate whether posterior only (Post-only) techniques consisting of pedicle screws, osteotomies and BMP-2 may eliminate the need for the anterior approach without sacrificing deformity correction, fusion rates or outcome. STUDY DESIGN/ SETTING: Retrospective matched cohort analysis PATIENT SAMPLE: 24 patients who had A/P fusion for primary adult scoliosis (16 staged, 8 same day) were matched with a cohort of 24 patients who had Post-only treatment

OUTCOME MEASURES: Minimum 2-year follow-up included radiographic, clinical and outcomes data METHODS: Anterior fusion was performed via a thoracotomy (n51)/ thoracoabdominal (n523) approach. All Post-only surgeries were under one anesthesia. RESULTS: There were no significant differences between groups for age, gender, diagnosis, co morbidities, preop curve magnitudes or global balance (see Table). Average surgical time was higher in the A/P vs Post-only group (11.6 hrs vs 6.9 hrs, p!.0001) as was total EBL (1330ml vs 980 ml, p5.04). Hospital Length of Stay (LOS) was longer in the A/P vs Post-only group (11.9 vs 8.3 days, p50.03). There were no significant differences between postop complications. Revision surgery was performed in 5 A/P pts (1 immediate postop for radiculopathy, 4 delayed for pseudoarthrosis) and 2 Post-only pts (1 immediate for coronal imbalance, 1 delayed for distal degeneration). Higher pseudoarthrosis rates A/P vs Post-only (17% vs 0%) were not significant (p50.11). SRS-30 and Oswestry scores reflected a similar patient assessment of outcome and function between groups both pre-op and at follow-up. CONCLUSIONS: In a matched cohort analysis comparing 24 patients undergoing anterior/posterior surgery versus posterior surgery alone for treatment of primary adult scoliosis, the posterior only approach was found to provide the same deformity correction as A/P fusion with similar complications, radiographic and clinical outcomes at over 2 year follow-up. Operative time, blood loss, and hospital length of stay were significantly lower in the posterior only treatment group, with a surprisingly lower pseudoarthrosis rate.