Biomechanical analysis of cervical multilevel oblique corpectomy: an in vitro study in sheep.

BACKGROUND: Anterolateral oblique corpectomy is an alternative approach to treatment of multilevel cervical spinal disease. It is stated that the approach does not cause instability in the patients with hard discs, so fusion or instrumentation is not required. The authors undertook a study on stability of the cervical spine by an animal model to establish if this approach causes instability. MATERIAL AND METHODS: Thirty-seven C3 to C6 spinal segments obtained from 3 to 4-year-old male sheep were used. In vitro maximal loading values were obtained from seven sheep cervical specimens for flexion, extension, lateral flexion in both directions, axial rotation in both directions and axial loading, and load deformation curves were drawn by an electrohydrolic testing machine. Other specimens were divided into three groups: Control (n=10), C4 (n=10) and C4-5 (n=10) groups. In two study groups, one or two level oblique corpectomies were performed. In the control and study groups, biomechanical tests were obtained according to the maximal loading values. Load-deformation curves were drawn and displacement amounts were determined for all seven movements. RESULTS: No statistically significant differences were observed in load deformation curves and displacement amounts between all three groups for seven movements. CONCLUSION: These results support the opinion that anterolateral oblique corpectomy does not cause cervical instability.

Treatment of terminal syringomyelia in association with tethered cord syndrome: clinical outcomes with and without syrinx drainage.

OBJECT: Current use of magnetic resonance (MR) imaging has led to increased awareness of the frequency of terminal syringomyelia in patients with tethered cord syndrome. However, that the surgical treatment of terminal syringomyelia is necessary remains unclear. In this study the authors attempted to assess the clinical impact, if any, brought after syrinx decompression on the clinical outcome of tethered cord syndrome. METHODS: They randomly assigned 30 cases of pediatric tethered cord into two treatment groups: those in whom an untethering procedure was performed (Group I) and those in whom this procedure was combined with syrinx decompression (Group II). The 1-year follow-up clinical results obtained in the two groups, in correlation with MR imaging findings, were compared to evaluate the benefit of added syrinx drainage. Clinical follow-up evaluation revealed that surgical drainage of the syrinx, when combined with spinal cord untethering, resulted in better outcomes in terms of resolution of sensory deficits (p = 0.036) and bladder dysfunction (p = 0.05). The improvement in clinical outcome correlated with the radiologically documented resolution of the syrinx cavity; however, response rates of symptoms differed for each tethering subgroup. CONCLUSIONS: Preliminary results of this study indicated that terminal syringomyelia should be considered as a comorbidity that contributes to the clinical outcome of patients with tethered cord syndrome. A better clinical outcome is achieved following successful decompression of the syrinx in addition to untethering the spinal cord. These findings emphasize the importance of recognizing, evaluating, and treating this pathological entity.