P5. Fullendoscopic Dorsal Foraminotomy vs. Ventral Decompression and Fusion in Cervical Lateral Disc Herniations: A Prospective Randomized Controlled Study

104S

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

hours. In group 1, SCBF was 76.166.2% 10 hours after ligation. The amplitudes of SCEPs remained higher than 70% and the amplitudes of CMAPs remained higher than 80% of the control values during the 10 hours. In group 2, SCBF was 66.666.6% 10 hours after ligation. The amplitudes of SCEPs and CMAPs remained higher than 60% of the control values during the 10 hours. In group 3, SCBF was 61.462.1% 10 hours after ligation. The amplitudes of SCEPs remained higher than 60% and the amplitude of CMAPs remained higher than 50% of the control values during the 10 hours. In group 4, SCBF was 53.565.5% 10 hours after ligation. Abnormal SCEPs and CMAPs were observed in 1 out of 3 dogs. Postoperative neurologic evaluation identified all 5 dogs in 3 pairs group and 4 in 4 pairs group as having grade 5. There was 1 dog in 4 pairs group that had grade 4. (grade 4, animal can walk: grade 5, animal can climb a 20 inclined plane). CONCLUSIONS: Interruption of bilateral segmental arteries at 4 or more consecutive levels including the level of Adamkiewicz artery risks producing ischemic spinal cord dysfunction. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.246

P5. Fullendoscopic Dorsal Foraminotomy vs. Ventral Decompression and Fusion in Cervical Lateral Disc Herniations: A Prospective Randomized Controlled Study Sebastian Ruetten, MD, PhD1, Martin Komp, MD, PhD1, Harry Merk2, Georgios Godolias1; 1Herne, Germany; 2Greifswald, Germany BACKGROUND CONTEXT: There are various techniques for the operation of cervical disc herniations. The most common today appears to be ventral decompression and fusion. It brings good results, but requires more major surgery with loss of segment mobility. Dorsal "keyhole foraminotomy" is also been used without fusion. This operation is now possible in a full-endoscopic technique. PURPOSE: The objective of the prospective randomized study was to compare ventral decompression and fusion (Group 1) to full-endoscopic dorsal decompression (Group 2) in lateral, soft disc herniations. STUDY DESIGN/ SETTING: Prospectice, randomized, controlled study. PATIENT SAMPLE: 35 patients each underwent conventional microsurgical ACDF, or decompression via full-endoscopic posterior cervical foraminotomy (FPCF). Randomization was open, since the patients may identify the operation procedure. OUTCOME MEASURES: In addition to general parameters, other information was obtained using the following instruments: a VAS for neck and arm pain, the German version of the North American Spine Society Instrument (NASS), Hilibrand criteria based on Smith and Robinson. METHODS: Inclusion criteria were: monosegmental mediolateral and lateral soft disc herniation, radicular pain. In Group 1, the operation was performed in known technique using a PEEK cage without plating. In Group 2, the operation was performed using 5.9-mm endoscopes with a 3.1-mm intraendoscopic working canal under continuous lavage. The follow-up lasted 24 months. 62 patients (88%) were followed. RESULTS: The mean operation time in Group 1 was 75 minutes., in Group 2 35 minutes There were no measurable blood loss and serious complications in either group. In Group 1, 2 patients had transient difficulty swallowing. In Group 2, transient numbness occurred twice. There was no operation-related neck pain in Group 2 after wound healing. One patient in Group 2 suffered recurrence. CT-examinations showed resection of less than 1/4 of the facettes in Group 2. There was no increasing instability or kyphosing in Group 2, in Group 1 no adjacent instability. 57 patients subjectively attained a satisfactory result. This corresponded to the significantly constant improvement recorded by the validated measuring instruments. There were no significant differences between the groups. CONCLUSIONS: Full-endoscopic dorsal foraminotomy is technically feasible and a potential alternative to ventral decompression and fusion. It enables a selective procedure with direct visualization, decompression

is rapid, sufficient and the complication rate is low. Traumatization of the access pathway and the structures of the spinal canal is reduced due to the minimally-invasive technique. Strict attention must be paid to the indication for lateral and soft disc herniation. Recurrences cannot be ruled out. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.247

P6. Are Preoperative HRQOL Scores Predictive of Clinical Outcomes after Lumbar Fusion? Leah Carreon, MD, MSc1, Steven Glassman, MD2, Mladen Djurasovic, MD1, John Dimar, II, MD1, John Johnson, MD2, Rolando Puno, MD2, Mitchell Campbell, MD2; 1Louisville, KY, USA; 2Leatherman Spine Center, Louisville, KY, USA BACKGROUND CONTEXT: Specific and generic measures of Healthrelated quality of life (HRQOL) such as the SF-36 and Oswestry Disability Index (ODI) are increasingly being used to evaluate effectiveness of treatments such as lumbar fusion for degenerative disorders of the lumbar spine. However, their use as a diagnostic tool to determine which patients will improve has been limited. PURPOSE: The purpose of this study is to determine the effect of pre-op MCS, pre-op PCS, pre-op ODI, predominance of back pain, BMI, age, smoking status, procedure performed, number of levels fused and worker’s compensation on HRQOL after lumbar fusion. These factors were selected as they may influence a surgeon’s decision-making process. STUDY DESIGN/ SETTING: Cross-sectional cohort. PATIENT SAMPLE: 489 patients who underwent lumbar fusion for degenerative spine disorders. OUTCOME MEASURES: SF-36, ODI, and numeric rating scales for back (BPNRS) and leg pain (LPNRS). METHODS: SF-36, ODI, BPNRS and LPNRS were collected prospectively, pre-operatively and two years, post-operatively in patients undergoing lumbar fusion for degenerative disorders. Linear regression modeling was used to determine the effect of pre-op MCS, pre-op PCS, pre-op ODI, predominance of back pain, BMI, age, smoking status, procedure performed, number of levels fused and worker’s compensation on the change in ODI and change in SF-36 PCS two years after lumbar fusion. Procedures performed included PSF, TLIF, AIF and circumferential fusion. RESULTS: Patients with better pre-op MCS (p50.008) and worse pre-op ODI scores (p!0.0001) achieved greater improvements in ODI. Worker’s compensation patients did significantly worse (p50.03). Patients with better pre-op MCS (p50.0004), better pre-op PCS (p50.0155) and worse preop ODI scores (p50.0210) achieved greater improvements in PCS. Those on worker’s compensation experienced lower changes in PCS, an effect that was nearly significant (p50.0644). There were no significant correlations between improvement in PCS and ODI and predominance of back pain, BMI, age, smoking status, procedure performed, and number of levels fused. Attempts at determining threshold values for MCS, PCS and ODI that are predictive of a patient achieving minimum clinically important difference for PCS and ODI using receiver-operating characteristic curves, pair-wise comparisons and recursive partitioning algorithms were unsuccessful. CONCLUSIONS: Patients with good pre-op MCS and poor pre-op ODI scores who are not on worker’s compensation are more likely improve after lumbar fusion. Non-modifiable pre-operative factors, operative and post-operative events may also affect clinical outcomes after lumbar fusion. Threshold values for MCS, PCS and ODI that are predictive of a patient achieving minimum clinically important difference for PCS and ODI could not be determined. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi:10.1016/j.spinee.2008.06.248