Evaluation and analysis of patient outcomes with an intrasegmental fixation system in lumbar spinal fusion.

BACKGROUND CONTEXT: A new spinal fixation system with polydirectional screws and modular links with interconnecting radial serrations has been developed. The system allows the linking of multiple points of fixation, two points at a time (intrasegmental fixation), thus eliminating the need for intraoperative contouring of rods or plates. PURPOSE: Evaluation of this new type of spine system was done through biomechanical studies, analysis of lumbar lordosis preservation postoperatively, and multicenter review of patient outcomes with a minimum of 1 year follow-up. STUDY DESIGN/SETTING: Biomechanical studies of the spine system were performed according to American Society for Testing and Materials (ASTM) standards. To evaluate the maintenance of lordosis, radiographs from the first 119 patients were reviewed by the authors. Analysis of patient outcomes consisted of a review of the first 259 patients who underwent spinal fusion surgery with the new spine system. PATIENT SAMPLE: Evaluation of patient outcomes consisted of 122 men and 137 women with an average age of 50+/-13 years (range, 22-96 years) and a mean follow-up of 20+/-6 months (range, 12-54 months). The patient population was at high risk for fusion failure, with 127 smokers (49%), 141 who had previous spine surgery (54%), 22 with osteoporosis (8%), 63 were obese (24%), and 32 with diabetes (12%). One hundred two patients (39%) had a one-level fusion, 105 patients (41%) had two levels fused, and 52 patients (20%) had three or more levels fused. The majority of patients (66%) were covered under workers' compensation. OUTCOME MEASURES/METHODS: Radiographic fusion was deemed successful when the presence of trabecular bridging bone from transverse process to transverse process was observed, as well as no fixation failure nor radiographic evidence of screw loosening. Clinical success was rated excellent, good, fair, or poor depending on the patients pain level, function, and pain medication intake. RESULTS: Biomechanical studies of this intrasegmental fixation system have shown it to be strong under both static and fatigue testing, with exceptional strength in compression bending. In evaluating preservation of lumbar lordosis, no statistically significant loss of lordosis was observed. Overall, radiographic fusion was noted in 229 of 259 patients (88%) and did not differ significantly (p>.10) by the number of levels fused. Clinically, 69 patients (27%) had an excellent result, 111 patients (43%) had a good result, 50 patients (19%) had a fair result, and 29 patients (11%) had a poor result. The high rate of successful patient outcomes did not differ significantly (p>.10) by the number of levels fused, or other patient or surgical variables, except for the satisfaction level of workers' compensation versus nonworkers' compensation. One hundred of 118 patients (85%) who were working before surgery returned to work at an average 9+/-4 months postoperatively (range, 2-20 months). The use of direct current (DC) stimulation in this population was reserved for patients with one or more risk factors for fusion failure and was noted to be of benefit. There were no recorded intraoperative complications, but postoperatively 5 device and 19 non-device-related complications (9%) were noted, which is comparable to other lumbar fusion series. CONCLUSIONS: The results of these analyses show consistent patient outcomes regardless of the number of levels fused with an intrasegmental system. This may be attributable to the increased biomechanical strength of the system at each segment, coupled with the ability of intrasegmental fixation to maintain sagittal plane balance through preservation of the patient's lordotic curve.

A controlled prospective outcome study of implantable electrical stimulation with spinal instrumentation in a high-risk spinal fusion population.

STUDY DESIGN: A series of 65 instrumented patients without stimulation were compared with a later series of 65 patients with instrumentation and implantable electrical stimulation. The groups were evaluated for risk factors, age, diagnostic groups, levels fused, and radiographic and clinical success. OBJECTIVES: To test the efficacy of electrical stimulation in instrumented high-risk lumbar fusions. SUMMARY OF BACKGROUND DATA: Spinal instrumentation and implantable electrical stimulation have been shown to improve fusion success rates. METHODS: All patients were instrumented via pedicle screws and autologous bone graft. Diagnostic groups were evaluated, and the risk factors in each group were identified and compared. Postoperation management and follow-up regimen were similar in each group. Radiographs were evaluated via Dawson's criteria and confirmed by an independent radiologist. Clinical success was evaluated via the Modified Smiley-Webster Scale and confirmed by a second orthopedic surgeon. RESULTS: Fusion success was 95.6% in the stimulated group compared with 87% in the nonstimulated group (P = 0.05). Clinical success was 91% in the stimulated group and 79% in the nonstimulated group (P = 0.02). In a workers' compensation subset, fusion success was 93% in the stimulated group and 81% in the nonstimulated group. Clinical success was 57% in the stimulated group and 46% in the nonstimulated group. CONCLUSIONS: The results from using both instrumentation and electrical stimulation in a high-risk pool of patients show a statistically significant difference, with higher rates of fusion and clinical success than in a similar pool that did not receive stimulation.

Diskitis in children.

Thirty-six patients diagnosed with diskitis from 1978 to 1988 and followed for an average of 29.2 months were reviewed. The study included 23 boys and 13 girls with an average age of 5.3 years. The initial symptoms varied, but distinct clinical patterns emerged and were identifiable in different age groups. Both the leukocyte count and sedimentation rate were elevated. Routine roentgenograms were positive for intervertebral disk space narrowing in 82% of cases, technetium bone scans positive in 72%, and magnetic resonance imaging positive in all recent cases. Treatment consisted of bed rest for all patients, plaster casts for 50%, antibiotics for 40%, and traction for 23%. Regardless of the treatment combination, the course of the disease in most children is benign. At the completion of the study, all patients were asymptomatic including three children who had recurrences. In spite of being asymptomatic, 74% had persistent roentgenographic changes. The administration of antibiotics appears to be appropriate when indicated, i.e., failure to respond to immobilization. Disk space aspiration or biopsy should be reserved for those cases that are refractory to immobilization and antibiotics.

Digital schwannoma in a skeletally immature child.

Soft tissue neoplasms of the hand are rare in general and even more uncommon in children. The most commonly considered diagnoses include ganglion, inclusion cyst, lipoma, subcutaneous foreign body granuloma, and tendon sheath xanthoma. Aside from pressure sensitivity, masses on the palmar aspect of the hand are often asymptomatic. The case reported here identifies a primary neural neoplasm (neurilemmoma) that involves a small peripheral nerve in the hand of a twelve-year-old child. The patient had no neurologic symptoms and illustrates the need to include neurilemmomas in the differential diagnosis of hand masses in children.

Subtalar stabilization of the planovalgus foot by staple arthroereisis in young children who have neuromuscular problems.

A new approach was developed for the treatment of planovalgus feet in children who have spastic cerebral palsy and are less than six years old. The procedure consists of subtalar stabilization (arthroereisis) with a Vitallium staple, and it corrects alignment, restores balance, and allows continued function. It is safe, technically simple, and efficient. Between 1980 and 1988, forty-eight arthroereises were done. The results of thirty-one procedures in twenty patients who were two to ten years and ten months old at the time of the operation were followed for an average of 4.1 years (range, two to seven years). Approximately 85 per cent of the results were excellent or good. Only one foot needed a revision; this was due to migration of the staple. At the most recent follow-up, the talocalcaneal angle had not changed in about 50 per cent of the feet. In another seven, the change ranged from 5 to 10 degrees. All of these patients had a satisfactory result. In all but three feet, the goal of maintaining the stability of the talocalcaneal joint without orthotics or osseous fusion was achieved. Originally, the procedure was done only in patients who were less than six years old, but, because of its success, the indications were extended to children of any age who had severely involved and neurologically compromised feet. Satisfactory results were obtained in the older children as well.