Implant complications, fusion, loss of lordosis, and outcome after anterior cervical plating with dynamic or rigid plates: two-year results of a multi-centric, randomized, controlled study.

STUDY DESIGN: Prospective, controlled, randomized, multicenter study. OBJECTIVE: To analyze implant complications and speed. SUMMARY OF BACKGROUND DATA: Rigid plate designs, in which the screws are locked to the plate, are in common use and thought to provide more fixation than dynamic designs, in which the screws may glide when the graft is settling. The aim of the study is to analyze (1) implant complications, (2) speed of fusion, (3) loss of lordosis, and (4) clinical outcome in both types of plates. METHODS: One hundred thirty-two patients were included and assigned by randomization to one of the groups in which they received a routine anterior cervical discectomy and autograft fusion with either a dynamic plate (ABC, study group) or a rigid plate (CSLP, control group). At discharge, after 3 and 6 months and finally after 2 years, implant complications, segmental mobility, absence of radiolucencies, absence of bone sclerosis, evidence of bridging trabecular bone, loss of lordosis, Visual Analog Scale (VAS) and Neck Disability Score were recorded. All radiographic measurements were performed by an independent radiologist. RESULTS: There have been 4 patients with implant complications within the control group and no implant complications within the study group, P = 0.045. Mean segmental mobility before discharge for the study group was 1.7 mm, 1.4 mm after 3 months, 0.8 mm after 6 months, and 0.4 mm after 2 years. For the control group, these values were 1.0, 1.8, 1.6, and 0.5 mm. The difference at 6 months between both groups was significant (P = 0.024). Neither absence of radiolucencies, nor absence of sclerosis, nor evidence of bridging bone showed significant differences between the 2 groups through the postoperative follow-up (P > 0.05). The loss of segmental lordosis for the study group with respect to intraoperative radiograph was 1.3 degrees at discharge and 4.3 degrees after 2 years. For the control group, these values were 0.9 degrees , 0.7 degrees . The difference at 2 years was significant (P = 0.003). Clinical postoperative outcome (VAS and ODI) was not different between the 2 groups through the postoperative follow-up (P > 0.05). CONCLUSION: Dynamic cervical plate designs provide less implant complications (no patient) compared with rigid plate designs (4 patients). Speed of fusion was faster in the presence of a dynamic plate. However, loss of segmental lordosis is significantly higher if dynamic plates are used, which did not result in differences regarding clinical outcome between dynamic and constrained plates after 2 years. Thus, dynamic plates should be considered to be the preferred treatment option because of the lower risk for implant failure-related revision surgery.

Segmental abdominal wall paresis caused by lateral low thoracic disc herniation.

STUDY DESIGN: Clinical, radiologic, and neurophysiologic description of 2 cases. OBJECTIVE: To describe 2 cases with spontaneous deep unilateral abdominal pain as the first symptom of thoracic disc herniation at a low thoracic vertebral level, further manifested by unilateral partial paresis of the obliquus abdominis muscle. SUMMARY OF BACKGROUND DATA: Clinical manifestation of lateral thoracic disc herniation with electrophysiologic results and conservative therapy as treatment of choice when spinal cord functions are preserved. METHODS: Magnetic resonance imaging revealed bilateral paramedian disc protrusions at T12-L1 in Patient 1 and foraminal herniation at T10-T11 and paramedian herniation at T11-T12 in Patient 2. Electromyography (EMG) and evoked potentials were investigated in the acute stage and after 6 months. RESULTS: Spontaneous activity on needle EMG confirmed axonal root impairment. Somatosensory and motor-evoked potentials were within normal limits and excluded spinal cord involvement. Nonsteroidal anti-inflammatory drugs and periradicular injection of steroids and local anesthetics rendered both patients pain-free. Normalization of muscle strength within 3 to 6 months was accompanied by EMG findings of reinnervation. CONCLUSION: Lateral disc herniation causing compression of a thoracic root associated with unilateral segmental paresis of the abdominal wall is a rare condition. Despite EMG documentation of axonal root lesion, however, a purely conservative therapeutic approach may be considered treatment of choice in cases without spinal cord involvement.

Selection of surgical procedures for treatment of failed back surgery syndrome (FBSS).

The paper presents the definition of failed back surgery syndrome (FBSS), current surgical treatment options and other pain control options. Available data indicates an occurrence rate of FBSS in 5-50% of cases. A steep increase of the number of performed spinal procedures has also led to an increase in the number of FBSS cases. FBSS is caused by a complex relation of different causes: biological, psychological. social and economic. Patient selection and correct indications are of key importance for successful surgical treatment of FBSS. The pathology to be addressed must be clearly defined in imaging studies, in order to perform the procedure that will yield optimal results. In over 50% with FBSS a psychological or behavioral dysfunction can be noted, and identification of such condition is part of FBSS prevention protocols. Surgical techniques for FBSS treatment include decompression, stabilization and fusion and dynamic neutralization procedures. These techniques are discussed in the paper.