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STUDY DESIGN: The efficacy of radiofrequency medial branch neurotomy to treat cervical zygapophysial joint pain from whiplash was compared prospectively in litigants and nonlitigants. OBJECTIVES: 1) To assess the effect of monetary gain on treatment of zygapophysial joint pain in cervical whiplash. 2) To determine whether radiofrequency medial branch neurotomy is effective treatment for whiplash. SUMMARY OF BACKGROUND DATA: The influence of litigation on treatment outcome is a subject of controversy in both the medical and legal professions. This is the first study to examine this issue in a prospective manner using a previously proven diagnostic and therapeutic method. METHODS: Sixty patients with cervical whiplash who remained symptomatic after 20 weeks of conservative management were referred for radiofrequency cervical medial neurotomy. The patients were classified as litigant or nonlitigant based on whether the potential for monetary gain via litigation existed. Each group underwent identical evaluation and treatment. Patients were observed for 1 year. Visual analogue scores and self-reported improvement were obtained before, immediately after, and 1 year after radiofrequency cervical medial neurotomy. RESULTS: Forty-six patients completed the study. The overall reduction in cervical whiplash symptoms and visual analogue pain scores were significant immediately after treatment (nonlitigants vs. litigants: 2.0 vs. 2.5, P = 0.36) and at 1 year (nonlitigants vs. litigants: 2.9 vs. 4.0, P = 0.05). One-year follow-up scores were higher than immediate post-treatment scores (nonlitigants vs. litigants: 2.5 vs. 3.6). The difference between litigants and nonlitigants in the degree of symptomatology or response to treatment did not reach significance. CONCLUSIONS: These results demonstrate that the potential for secondary gain in patients who have cervical facet arthropathy as a result of a whiplash injury does not influence response to treatment. These data contradict the common notion that litigation promotes malingering. This study also confirms the efficacy of radiofrequency medial branch neurotomy in the treatment of traumatic cervical facet arthropathy.

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STUDY DESIGN: An outcome questionnaire was constructed to evaluate patient satisfaction and performance and to discriminate among patients with adolescent idiopathic scoliosis. OBJECTIVES: To determine reliability and validity in a new quality-of-life instrument for measuring progress among scoliosis patients. SUMMARY OF BACKGROUND DATA: Meta-analysis of the surgical treatment of adolescent idiopathic scoliosis determined that a uniform assessment of outcome did not exist. In addition, patient measures of well-being as opposed to process measures (e.g., radiographs) were not consistently reported. This established the need for a standardized questionnaire to assess patient measures in conjunction with process measures. METHODS: The instrument consists of 24 questions divided into seven equally weighted domains as determined by factor analysis: pain, general self-image, postoperative self-image, general function, overall level of activity, postoperative function, and satisfaction. The questionnaire takes approximately 5 minutes to complete and is taken at predetermined time intervals. A total of 244 of patients from three different sites responded to the questionnaire. RESULTS: The reliability based on internal consistency was confirmed with a Cronbach's alpha coefficient greater than 0.6 for each domain. In addition, acceptable correlation coefficient values greater than 0.68 were obtained for each domain by the test-retest method on normal controls. Similarly; to establish validity of the questionnaire, responses of normal high school students were compared with that of the patients. Consistent differences were noted in the domains between the two groups with P < 0.003. The largest differences were in pain (control, 29.96 +/- 0.20; patient, 13.23 +/- 5.55) and general level of activity (control, 14.96 +/- 0.20; patient, 12.16 +/- 3.23). Examination of the relationship between the domains and patient satisfaction showed that pain correlates with satisfaction to the greatest degree (Pearson's correlation co-efficient, r = -0.511; P < 0.001), followed by self-image (r = 0.412; P < 0.001). CONCLUSIONS: This questionnaire addresses patient measures for evaluation of outcome in adolescent idiopathic scoliosis surgery by examining several domains. It also allows for dynamic monitoring of scoliosis patients as they become adults. This is a validated instrument with good reliability measures.

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STUDY DESIGN: A three-group design with consistent pullout strength measures. OBJECTIVES: To determine pullout strength of three fixation types (unicortical screws, bicortical screws, wires) and to investigate their correlation with respect to occipital morphology. SUMMARY OF BACKGROUND DATA: A secured, multidirectional occipitocervical fusion requires internal fixation. Devices secured at occipital protuberance were suggested to offer the greatest pullout strength because of this region's thickness. METHODS: Twelve fresh human cadaveric occiputs were sketched with a grid delineating 21 fixation sites. Each site was drilled and hand-tapped. Four specimens were instrumented with unicortical screws on one side of the midline and bicortical screws on the other. Another four were instrumented with bicortical screws and wires, and the remaining four were instrumented with unicortical screws and wires. Two points on each specimen were secured with identical fixation to examine side-to-side symmetry. An MTS materials testing apparatus (MTS Systems Corporation, Eden Prairie, MN) was used to displace the fixators. Pullout strengths at different anatomic locations were recorded. RESULTS: The greatest pullout strength was at the occipital protuberance for all fixation types. The bicortical pullout strength was 50% greater than unicortical. The wire pullout strength was not significantly different from that of the unicortical screw (P > 0.05). Seventy-eight percent of wires broke at 1100 N. Unicortical pullout strength at occipital protuberance was comparable with that of the bicortical screw at other locations. CONCLUSIONS: Unicortical screw fixation at occipital protuberance offers acceptable pullout strength without the potential complications of bicortical screws or wire fixation.

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STUDY DESIGN: One hundred twelve fresh cadaveric spines were harvested using a newly described technique. OBJECTIVES: To develop and describe a technique for the expeditious excision of intact human cadaveric spines for biomechanical testing, to educate the dissector on the health and safety issues involved in harvesting spinal specimens, and to review the present recommendations for storage and preservation of spinal segments. SUMMARY OF THE BACKGROUND DATA: As the need for biomechanical spinal research continues to expand, the demand for fresh human cadaveric vertebral specimens increases. Previous techniques for harvesting are simplistic and sparse. This technique offers a reliable and expeditious method for procurement of spinal vertebral segments of any size. METHODS: Human cadaveric spines were harvested using an adaptation of previous posterior spinal approaches. Techniques for sectioning each vertebral region were developed. Detailed description of these techniques was meticulously documented. The procured spinal segments have been used for multiple biomechanical investigations. RESULTS: The technique has been used successfully in more than 100 spinal harvests. Approximate time required is 30 minutes. The harvested segments have been reliable biomechanical specimens in many published studies. CONCLUSIONS: A new technique for the rapid extraction of human cadaveric spines has been developed. Dissectors may benefit from the recommendations offered for sectioning of each region.

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At times one pedicle screw cannot be used in a posterior construct because of morphometric reasons or when the pedicle is fractured intraoperatively. It is not clear from the literature whether and to what extent a construct's stability is compromised by substituting a hook claw for one pedicle screw. A synthetic vertebra model using a hook claw in lieu of a pedicle screw in a compressive and torsional mechanical study is evaluated. Isola screw-based constructs varying in the number of pedicle screws and hook claws were used. To recreate a realistic clinical scenario, transverse connectors and a Harms cage were used as well. In compression, substituting screws with claws did not substantially change the stiffness, whereas substituting one or two pedicle screws with one or two hook claws significantly reduced torsional stiffness. We conclude that using one or two hook claws is a viable alternative for pedicle screws when the latter cannot be used in a clinical situation, especially as an adjunct when the anterior column is reconstructed.

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