P155. Intraesophageal retraction pressure during anterior cervical plating vs. cervical disc replacement

Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S OUTCOME MEASURES: Subjects were scored via 0–10 point numeric pain rating scale (NRS). Comparing parameters of discography with psychometric scores and pain tolerance, non-painful discs were excluded. The pressure (psi) associated with a given pain response was noted. The pressure (Evo-Pre) and injected volume (MVPE) at which pain was first evoked, the NRS values at 15, 30, and 50 psi above opening pressure and maximal NRS during ⬎50 psi intradiscal stimulation were recorded. METHODS: Patients were assigned into one of three groups based on their psychometric test findings: normal (N, Zung scale ⬍25), risk (R, Zung scale 25–48 and MSPQ ⬍12), and abnormal (distressed-depressive; Zung scale ⬎48, and distressed-somatic; Zung 25–48 and MSPQ ⬎12). To assess patient pain tolerance, a pain report was elicited after skin puncture by 25 G needle and injection of local anesthetics into the subcutaneous tissue. Pain was evaluated by a standard verbal Numeric Rating pain Scale (Anesth-NRS), 0–10 scale with 0 meaning “the best pain tolerance” and 10 meaning “the worst pain tolerance”. Patients were assigned into one of two groups based on their pain threshold. The standard score of AnesthNRS dividing subgroups was 5/10, a severe pain complain at skin local analgesia; high pain threshold group—0 ⭐ Anesth-NRS ⬍5 and low pain threshold group – 5 ⭐ Anesth-NRS ⭐10. RESULTS: Grouping by psychometric results, positive rates of discography were 69% in normal (N) group, 66.7% in the risk (R) group, 75% in the distressed-depressive (DD) group and 25% in the distressed-somatic (DS) group. No correlation was found to exist between the combined MSPQ and Zung psychometric scores and the primary discographic finding (positive vs. negative) nor between other subset discographic variables such as the mean volume at which pain was evoked [MVPE] or between the pain on intradiscal injections [PI]. The pain tolerance rated by the pain reported during local anesthetic injections (Anesth-NRS) showed a moderate correlation with the maximal evoked pain during ⬎50 psi intradiscal stimulation (r⫽.408). Evoked pains at 15 psi and 50 psi had weak correlation with Anesth-NRS, (r⫽.246 and r⫽.245, respectively). The weak correlation between psychometric testing scores and Anesth-NRS were revealed (r⫽.241). CONCLUSIONS: The results suggest that pressure controlled manometric lumbar discography may not to be influenced significantly by psychological factors in study with chronic axial pain patients, although pain tolerance have some impact. Patient pain tolerance should be considered as a potential confounding factor when establishing a positive result discography. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.368

P154. Participation and supervision of residents and fellows during spinal surgery—a national survey and analysis Dimitry Kondrashov1, Farhan Siddiqi1, Victor Hayes2, Jared Brandoff 3*, Rohit Verma4, Jeff Silber5; 1North Shore–Long Island Jewish Health System, New Hyde Park, NY, USA; 2New Hyde Park, NY, USA; 3Long Island Jewish Medical Center, New Hyde Park, NY, USA; 4Long Island Jewish Hospital, New Hyde Park, NY, USA; 5Long Island Jewish Medical Center, Great Neck, NY, USA BACKGROUND CONTEXT: Resident teaching in spinal surgery is dependent on several factors. To date, no studies have analyzed resident teaching as training progresses. This study presents new information on factors influencing teaching of residents during spinal procedures. PURPOSE: To present factors that affect the level of resident teaching and develop a standard timeline of education for spinal surgery. STUDY DESIGN/SETTING: Questionnaires were sent to 152 ACGME Orthopaedic Programs to be distributed to spine surgeons responsible for resident education. PATIENT SAMPLE: A total of 96 responses were received and analyzed. METHODS: Surveys were filled out by surgeons at each institution with regard to specific procedures that given PGY levels are allowed to perform under direct supervision. Procedures encompassed cervical, thoracic, and

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Fig. 1. Timeline detailing the national average PGY level with regard to specific spinal procedures. Table 2: Statistically significant factors of a residency program that affect resident training. lumbar instrumentation as well as neural decompression and complication rates. RESULTS: In summary, there is no statistically significant difference in the perceived complication rate of spinal procedures regardless of the year in training of the assisting surgeon (Fig. 1). CONCLUSIONS: We reported the national average for resident participation in spinal procedures as a function of year in training. We identified significant factors that affect resident training; affiliation with a spine fellowship, a spine service, academically based, large cities, heavy case volume, multiple residents specializing in spine, and large programs. This data is useful to plan a standardized education timeline in accordance with a national consensus. Also, may be utilized by both fellowship directors and residency applicants to gauge the degree of surgical experience at a residency program. In conclusion, this data suggests that a common education standard is possible to achieve. Second, perceived complication rates are not affected by earlier training. Finally, resident education may be deleteriously affected by training in large academic urban programs affiliated with spinal fellowships subjected to large case volumes. DISCLOSURES: No disclosures. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.369

P155. Intraesophageal retraction pressure during anterior cervical plating vs. cervical disc replacement Paul Tortolani1, Bryan Cunningham, MSc2, Franco Vigna3, Nianbin Hu, MD2, Candace Zorn2, Paul McAfee, MD4; 1Orthopaedic Associates, Baltimore, MD, USA; 2Union Memorial Hospital, Baltimore, MD, USA; 3 Spine and Scoliosis Center, Baltimore, MD, USA; 4Spine and Scoliosis Center, Towson, MD, USA BACKGROUND CONTEXT: Dysphagia is a well-recognized complication following anterior cervical discectomy and fusion, observed as high as 50% by videofluoroscopic evaluation postoperatively. Esophageal injury due to surgical retraction is one mechanism by which swallowing difficulties may ensue. There are limited published data evaluating the effect of soft tissue retraction on intra-esophageal pressures during anterior cervical instrumentation procedures. PURPOSE: The purpose of this study was to 1) measure the intra-esophageal pressure secondary to retraction during anterior instrumentation, 2) determine if any pressure differences exist between plating and cervical disc replacement, and 3) whether the surgical level or length of the plate influences the magnitude of intra-esophageal pressure during retraction. STUDY DESIGN/SETTING: An analysis of intra-esophageal pressure during soft tissue retraction was performed for anterior single-level and three-level cervical plating as well as cervical disc replacement. PATIENT SAMPLE: 7 Fresh Frozen Cadavers. OUTCOME MEASURES: Iintra-esophageal pressure measured with a transducing catheter, 180cm length, 3mm diameter, sensitivity range ⫾250mm Hg with 4 circumferential sensors positioned 5cm apart. Data acquisition using Esophageal Manometry System and Polygraph for Windows software. METHODS: Using a 4 cm transverse incision, a Smith-Robinson anterior approach to the cervical spine was performed on seven fresh frozen cadavers. Correct placement of an esophageal pressure-transducing catheter was confirmed using a laryngoscope, manual palpation of the esophagus and fluoroscopic imaging. Three surgical instrumentation groups were used for comparisons: 1) Single-level plate 2) Single-level Porous Coated Motio (PCM) cervical disc replacement and 3) 3-level plate. Hand-held appendiceal retractors were used to retract the soft tissues during screw insertion into the plate and during application of the disc prosthesis into the interspace. Care was taken to exert just enough force on the retractors to allow

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Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S

the surgeon to get the desired implant into the correct position. Fluoroscopy confirmed that the pressure sensors were directly behind the retractors during data acquisition. RESULTS: Significantly greater intra-esophageal pressures were demonstrated for single-level cervical plating at C5/6 compared with C3/4 (p⫽.036). Similarly, there was significantly greater pressures recorded at C5/6 versus C3/4 for the 3-level plating group (p⬍.001). In contrast, there was no statistically significant difference in pressures observed during disc replacement at C5/6 compared with C3/4 (p⫽.084). Significantly greater pressures were recorded during single-level plating compared with disc replacement at both C3/4 (p⫽0.016) and C5/6 (p⫽0.016). 3-level plating demonstrated significantly greater pressures at C5/6 compared with disc replacement (p⬍.001) but no statistically significant difference compared with disc replacement at C3/4 (p⫽.333). The highest mean pressure,

154.5⫾49.5 mm Hg, was recorded at C5/6 level during insertion of the 3level plates. CONCLUSIONS: Anterior cervical plating results in significantly greater intra-esophageal pressures when performed at C5/6 compared with C3/4. This holds regardless of whether the plate spans the distance from C3 to C6 (3-level plate) or spans the single C5/6 level. In addition, the insertion of the cervical disc replacement appears to require less esophageal retraction and hence reduced intra-esophageal pressures when compared with anterior cervical plating. DISCLOSURES: FDA device/drug: Porous Coated Motion (PCM) cervical disc replacement. Status: Investigational/not approved. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/j.spinee.2005.05.370