Radiographic criteria for placement of translaminar facet screws.

BACKGROUND CONTEXT: Screw fixation of the facet joint has been reported to stabilize the lumbar spine and facilitate spinal fusion. Accurate placement of translaminar facet screws (TLFSs) requires identification of the posterior spinal elements, and the facet joints in particular, which may be facilitated by intra-operative fluoroscopy. PURPOSE: The purpose of this study was to define the radiographic parameters that will allow for successful placement of TLFSs. STUDY DESIGN: Eighteen TLFSs were placed in three human cadaver spines using fluoroscopic guidance, with screws placed from L3-L4 to L5-S1 bilaterally. After screw placement, the spines were dissected and examined for accuracy of screw placement. METHODS: In the first cadaver spine, TLFSs were placed with direct visualization of the posterior lumbar spine, during which a fluoroscopic image intensifier was used to define the appropriate radiographic parameters for safe placement of the screws. Bilateral TLFSs were then placed percutaneously using the radiographic parameters developed, after which the spines were dissected to examine the positions of the screws. RESULTS: The radiographic views identified to achieve proper TLFS placement were a true lateral, anteroposterior (AP), a 45-degree oblique and an AP view with the X-ray bean at 30- to 45-degree cephalad angle ("spinal outlet" view). Using these views and the defined radiographic criteria, proper positioning of percutaneously placed TLFSs was achieved, with no spinal canal breaches found. CONCLUSIONS: This study defines intra-operative radiographic criteria that will assist in placement of TLFSs. The use of this technique may allow for screw placement with less extensive exposure of the posterior spine.

Early radiographic and clinical results of balloon kyphoplasty for the treatment of osteoporotic vertebral compression fractures.

STUDY DESIGN: A prospective consecutive cohort study of clinical and radiographic outcomes after kyphoplasty for treatment of osteoporotic vertebral compression fractures. OBJECTIVES: To measure changes in spinal deformity, activity level, and pain after kyphoplasty treatment. SUMMARY OF BACKGROUND DATA: Pain and kyphosis caused by osteoporotic vertebral compression fractures adversely affect quality of life and survival. Kyphoplasty involves the inflation of a balloon bone tamp, percutaneously placed in a fractured vertebral body, followed by deposition of bone cement into the resulting cavity. Previous reports indicate that kyphoplasty improves patient function and restores height of collapsed vertebral bodies, but limited data about the effects of kyphoplasty on spinal sagittal alignment are available. METHODS: Twenty-nine patients with osteoporotic vertebral compression fractures who did not respond to medical therapy were treated by kyphoplasty. These patients underwent 37 operations to treat 61 vertebral compression fractures between T6 and L5. Sagittal alignment was analyzed from standing radiographs (pre- and postkyphoplasty). Patient surveys were used to assess pain relief, improvement in activity, and satisfaction with the surgical procedure. RESULTS: In this cohort, a mean of 8.8 degrees (range 0-29 degrees ) of correction of local spinal kyphosis was achieved with kyphoplasty. Thirty of 52 fractures (17 patients) were considered reducible and had >5 degrees of correction, with a mean improvement in sagittal alignment of this population of 14.2 degrees. Patient surveys revealed significant pain reduction within the first week after surgery and improved activity levels for a majority of patients. CONCLUSIONS: Kyphoplasty improves physical function, reduces pain, and may correct kyphotic deformity associated with vertebral compression fractures.

Newborn with an open posterior hip dislocation and sciatic nerve injury after intrauterine radiofrequency ablation of a sacrococcygeal teratoma.

Advanced prenatal ultrasonography techniques have allowed for better understanding of the natural history, treatment, and prognosis of sacrococcygeal teratomas. Several intrauterine surgical techniques to debulk the tumor when fetal and maternal life are in jeopardy have been described. Orthopaedic impairment, such as lower extremity weakness and swelling, also has been described in association with sacrococcygeal teratomas. The authors report on a newborn in whom a large soft tissue defect overlying the posterior hip region with direct exposure of the disarticulated hip joint existed at the time of birth, which resulted from intrauterine radiofrequency ablation of a sacrococcygeal teratoma. This unexpected complication has resulted in a loss of sciatic nerve function, malformation of the acetabulum and femoral head, and loss of the left ischium, coccyx, inferior sacrum, gluteal, adductor and piriformis muscles, and posterior hip capsule. At 16 months of age, the patient has a flaccid left lower extremity with a hypoplastic hip joint.