Radiation exposure during the lateral lumbar interbody fusion procedure and techniques to reduce radiation dosage.

BACKGROUND: Fluoroscopy is widely used in spine surgery to assist with graft and hardware placement. Previous studies have not measured radiation exposure to a surgeon during minimally invasive lateral lumbar spine surgery for single-level discectomy and interbody cage insertion. This study was performed to model and measure radiation exposure to a surgeon during spine surgery using the direct lateral lumbar procedure. METHODS: The study was performed using a mannequin substituting for the surgeon and a cadaver substituting for the patient. Radiation was measured with dosimeters attached to 6 locations on the mannequin using a OEC Medical Systems 9800 C-arm fluoroscope (OEC Medical Systems, Salt Lake City, Utah). Three different fluoroscopy setups were tested: a standard imaging setup, a standard setup using pulsed-mode fluoroscopy, and a reversed setup. The experiment was tested 5 times per setup, and the dosimeters' values were recorded. RESULTS: The highest amount of radiation exposure occurred when obtaining an anteroposterior view of the spine in the standard setup. Compared with the standard setup, the pulsed-mode setting decreased the radiation exposure to the mannequin by a factor of 6 times (P < .001). Compared with the standard setup, the reversed setup also decreased the radiation exposure to the mannequin by a factor of 6 times (P < .001) and it had the lowest amount of radiation exposure to the eye level (P < .001). CONCLUSIONS: Care should be taken when one is obtaining an anteroposterior view of the lumbar spine during lateral lumbar procedures to limit radiation exposure. Radiation exposure to the surgeon can be greatly minimized by using either a pulsed imaging mode or the reversed setup. The reversed setup has the lowest amount of radiation exposure to the eye level.

Predictors and prevalence of patients undergoing additional kyphoplasty procedures after an initial kyphoplasty procedure.

BACKGROUND CONTEXT: Vertebral cement augmentation, including kyphoplasty, has been shown to be a successful treatment for pain relief for vertebral compression fracture (VCF). Patients can sustain additional symptomatic VCFs that may require additional surgical intervention. PURPOSE: To examine the prevalence and predictors of patients who sustain additional symptomatic VCFs that were treated with kyphoplasty. STUDY DESIGN: A retrospective review of patients who previously underwent kyphoplasty for VCFs and had additional VCFs that were treated with kyphoplasty. PATIENT SAMPLE: A total of 256 patients underwent kyphoplasty for VCFs from 2000 to 2007 at a single medical center. OUTCOME MEASURES: The outcome measure of interest was the need for an additional kyphoplasty procedure for a symptomatic VCF. METHODS: Risk factors such as age, sex, smoking status, and steroid use were assessed, as well as bisphosphonate use. Sagittal spinal alignment via Cobb angles for thoracic, thoracolumbar, and lumbar regions was assessed. RESULTS: About 22.2% of the patients had an additional symptomatic VCF that was treated with a kyphoplasty procedure. Steroid use was the only significant risk factor for predicting patients with additional symptomatic VCFs who underwent additional kyphoplasty. The average time to the second VCF was 33 days. Adjacent-level VCFs were most common in the thoracic and thoracolumbar spine. Bisphosphonate use was not shown to be protective of preventing additional VCFs during this follow-up period. CONCLUSION: This is the first single-center review of a large cohort of patients who underwent additional-level kyphoplasty for symptomatic VCFs after an index kyphoplasty procedure. Our results suggest that patients with a VCF who use chronic oral steroids should be carefully monitored for the presence of additional symptomatic VCFs that may need surgical intervention. Patients with prior thoracic VCFs who have additional back pain should be reevaluated for a possible adjacent-level fracture.

Perioperative complications of combined anterior and posterior cervical decompression and fusion crossing the cervico-thoracic junction.

STUDY DESIGN: Retrospective review. OBJECTIVE: To determine the perioperative complications for patients undergoing single stage, multilevel, anterior, and posterior cervical fusions crossing the cervico-thoracic junction. SUMMARY OF BACKGROUND DATA: Cervical spinal stenosis with kyphosis involving 3 or more disc levels is often treated via combined anterior decompression and posterior instrumented fusion. When long cervical fusions end at C7, many surgeons extend the posterior fusion across the cervico-thoracic junction to reduce the potential for adjacent segment breakdown. Perioperative complications associated with these procedures have not previously been described. METHODS: A retrospective review of perioperative complications occurring in patients undergoing combined anterior decompression and posterior instrumented arthrodesis crossing the cervico-thoracic junction. The effect of operative time, blood loss, and fluid replacement on the need for extended intubation was tested with a Fisher exact test. RESULTS: Thirteen patients fit the inclusion criteria. Nine patients experienced at least 1 complication (69%, 9/13) during the perioperative period, comprising 16 minor and 5 major complications. The most common complications were dysphagia (46%, 6/19) and airway edema requiring extended intubation (38%, 5/13). CONCLUSION: Complications are frequent following these procedures, although the majority were minor and resolved without lasting effect. Airway edema requiring prolonged intubation or reintubation was frequent. With the numbers available, we were unable to show a relationship between the need for extended intubation and variables including operative time, blood loss, or volume of fluid replacement.

Ketorolac and spinal fusion: does the perioperative use of ketorolac really inhibit spinal fusion?

STUDY DESIGN: Retrospective review. OBJECTIVE: To evaluate the effect of postoperative use of ketorolac (Toradol) on spinal fusion in humans. SUMMARY OF BACKGROUND DATA: The value of parenteral ketorolac in postoperative analgesia has been well documented across surgical specialties. However, some studies have shown that ketorolac may adversely affect osteogenic activity and fracture healing. METHODS: A total of 405 consecutive patients who underwent primary lumbar posterolateral intertransverse process fusion with pedicle screw instrumentation were included in this retrospective study. A subtotal of 228 patients received Toradol after surgery for adjunctive analgesia. Each patient received a mandatory dose of 30 mg intravenously every 6 hours for 48 hours. The same surgeon performed the fusion procedure on all of these patients. Historical controls included 177 patients who did not receive Toradol after surgery. The minimum follow-up period was 24 months. Nonunions were diagnosed by analyzing sequential radiographs, flexion-extension radiographs, and computed tomography with multiplanar reconstructions. The gold standard of surgical exploration was performed in symptomatic patients with diagnostic ambiguity or nonunions diagnosed by imaging. RESULTS: There were no smokers in the study population. Pseudarthrosis was identified in 12 of 228 patients (5.3%) who received Toradol after surgery, and in 11 of 177 patients (6.2%) who did not. There was no significant difference detected in the nonunion rates between the two groups (P > 0.05, chi2 method). CONCLUSION: Use of ketorolac after spinal fusion surgery in humans, limited to 48 hours after surgery for adjunctive analgesia, has no significant effect on ultimate fusion rates.

Mechanical comparison of posterior instrumentation constructs for spinal fixation across the cervicothoracic junction.

STUDY DESIGN: A biomechanical study comparing 4 different posterior implant configurations for instrumentation across the cervicothoracic junction. OBJECTIVE: To compare mechanical parameters during flexion bending and axial rotation testing among 4 different posterior cervicothoracic rod-and-screw constructs. SUMMARY OF BACKGROUND DATA: Several posterior rod constructs are available for instrumentation across the cervicothoracic junction. No studies have examined the mechanical properties of constructs of varying rod diameters and rod connector types. METHODS: Four different rod-and-screw-based constructs for posterior cervicothoracic instrumentation underwent flexion bending or axial rotation testing. Stiffness, ultimate and yield forces (torques) were compared using an analysis of variance. RESULTS: Significantly lower stiffness, ultimate and yield force (torque) was observed with a 3.5-mm rod construct compared with the 3 other constructs. No significant differences were demonstrated between a dual diameter rod (3.5 mm to 5.5 mm) and a solid domino connector extending between 3.5-mm and 5.5-mm rods. A hinged domino connector construct between 3.5-mm and 5.5-mm rods had similar stiffness but lower ultimate and yield force from either the dual diameter rod or the solid domino construct. CONCLUSIONS: The present results demonstrate that the 3.5-mm rod-and-screw construct is the weakest configuration for posterior fixation across the cervicothoracic junction. The dual diameter rod and fixed domino connector constructs were the strongest and demonstrated similar values for yield and ultimate force.