The effect of intraoperative hip position on maintenance of lumbar lordosis: a radiographic study of anesthetized patients and unanesthetized volunteers on the Wilson frame.

STUDY DESIGN: The effect of intraoperative hip position on maintenance of lumbar lordosis was evaluated radiographically in 13 anesthetized patients and 14 unanesthetized volunteers positioned on a Wilson frame (MDT Corp., Torrance, CA). OBJECTIVES: To evaluate the effect of hip position on total and segmental lumbar lordosis in patients and volunteers in standardized positions: standing and with hips extended and flexed on a Wilson frame. SUMMARY OF BACKGROUND: Preservation of lordosis during instrumented lumbar fusion is critical for maintenance of normal sagittal alignment. It is customary to extend the hips on certain positioning devices to maximize lordosis maintenance. However, little information exists concerning the degree to which this actually affects lumbar lordosis. Further, the question of how individuals are specifically affected intraoperatively by differences of position on the same device remains unanswered. METHODS: Preoperative standing and intraoperative lateral lumbar spine radiographs with patients' hips in standardized flexed and extended positions were obtained (n = 13). Similar radiographs were obtained of asymptomatic volunteers (n = 14). Lumbar lordosis (L1-S1) and intervertebral body angles at each level were measured. Data were analyzed for changes in total and segmental lordosis between standing and intraoperative positions for all subjects. RESULTS: In the patient group, 95% of preoperative standing lordosis was maintained with the patients' hips extended. With hips flexed from 19 degrees to 48 degrees (mean, 33 degrees), 74% of lordosis was maintained. In the volunteer group, 98% of standing lordosis was maintained with volunteers' hips extended; with their hips flexed 20 degrees to 36 degrees (mean, 28 degrees), 86% of lordosis was maintained. CONCLUSIONS: Hip flexion was associated with a significant decrease in lordosis in patients and volunteers. Positioning in maximal hip extension optimizes lordosis preservation. While other devices have been shown to have specific effects on lordosis, the Wilson frame can permit easy adjustment of the lumbar sagittal contour to facilitate either preservation or reduction in lordosis.

Pelvic fractures after long lumbosacral spine fusions.

STUDY DESIGN: A retrospective review of late pelvic ring fractures after long spine fusions to the lumbosacral spine. OBJECTIVES: To review the clinical course and predisposing features of late fractures of the pelvic ring, usually atraumatic, in patients with long fusions to the lumbosacral spine. SUMMARY OF BACKGROUND DATA: Fractures of the pelvic ring after long fusions to the lumbosacral spine is a heretofore rarely reported complication. METHODS: Records from the authors' institution from 1985 to 1994 were reviewed retrospectively. Two hundred sixty-eight patients with long fusions to the lumbosacrum were identified. RESULTS: Between 1985-1994, five patients suffered late atraumatic fractures of the pelvic ring after long instrumented fusions to L5 or the sacrum. All fractures were on the left side of the pelvic ring, primarily the public rami. All patients were women, and at the time of fracture, all were aged 50 years or older. Fractures occurred from 4 months to 7 years after the last surgery (mean, 28 months). All were treated with protected weightbearing until comfortable. At average 27 months' follow-up evaluation, four patients reported no pain; the fifth had become pain-free at 31 months, but 2 months later, the patient spontaneously fractured the contralateral public rami. CONCLUSION: Stress-type fractures of the pelvic ring are a potential source of late pain after long fusions to the lumbosacral spine. Orthopedic surgeons should be aware of this possibility, especially in older, potentially osteoporotic women. Early treatment with simple protected weightbearing appears satisfactory and can prevent significant morbidity.

Radiographic evaluation of instability in spondylolisthesis.

STUDY DESIGN: The amount of intervertebral motion seen during dynamic radiography when imaged with the patient in the standing position was compared with that obtained with the patient in the lateral decubitus position. SUMMARY OF BACKGROUND DATA: Regarding analysis of spondylolisthesis, whether flexion/extension radiographs should be obtained with the patient in the lateral decubitus or standing position has been anecdotal. METHODS: Fifty consecutive adult patients with spondylolisthesis underwent flexion/extension lumbar spine radiographs in both positions. Abnormal motion was considered above 12 degrees dynamic angulation or 8% translation. RESULTS: Thirty-one of 50 patients displayed abnormal translation. Of these, 18 had abnormal motion only when they were examined in the lateral decubitus position and not when standing. Nine displayed excessive motion in both positions. Only four displayed more translation while standing. There was no statistical difference in the evaluation of dynamic angulation based on patient position. Neither age, degree of slip, listhetic level, nor type of spondylolisthesis correlated with abnormal motion. CONCLUSIONS: When spondylolisthesis is being analyzed, to maximize motion, flexion/extension radiographs should be obtained in the lateral decubitus position.

Thoracoplasty for the treatment of rib prominence in thoracic scoliosis.

OBJECTIVES: The authors evaluated the reduction of rib prominence in patients who underwent thoracoplasty versus matched control patients who underwent fusion without thoracoplasty. SUMMARY OF BACKGROUND DATA: Correction in rib prominence with thoracoplasty is not well quantified in the literature. The role of rib bone graft as an alternative to iliac crest is unknown. METHODS: Fifty patients who underwent thoracoplasty were reviewed and compared with 26 patients who underwent fusion without thoracoplasty. Rib prominence, clinical data, and patient outcome were evaluated. RESULTS: The mean reduction in rib prominence was 71% in the thoracoplasty group and 17% in the control group. There was no difference in estimated blood loss, operative time, and length of hospitalization. Satisfaction with thoracoplasty was high. CONCLUSIONS: Thoracoplasty is more effective than fusion alone for reduction of rib prominence in thoracic scoliosis; it provides ample, effective bone graft for fusion.

Magnetic resonance imaging of the brain stem in adolescent idiopathic scoliosis.

The cause of adolescent idiopathic scoliosis remains an enigma. Several studies have demonstrated abnormalities of posture, proprioception, and equilibrium control in patients with adolescent idiopathic scoliosis. These functions are integrated by structures in and around the brain stem. Twenty-seven patients with adolescent idiopathic scoliosis were studied with magnetic resonance imaging to delineate the anatomy of the brain stem in such patients. Imaging was conducted from the hypothalamus to the spinal cord at C3 in 26 patients; the remaining patient underwent an incomplete study because of a claustrophobic reaction. The study group consisted of 25 females and 2 males with an average age of 16 + 5 years. There were 19 right thoracic curves, 5 thoracolumbar curves, and 3 left lumbar curves. The mean primary curve size was 27 degrees at the most recent clinical evaluation. Seven patients were treated with observation, 14 with bracing, and 6 with surgery. The magnetic resonance imaging studies were read independently by three attending radiologists in a randomized, blinded fashion along with the magnetic resonance imaging studies of 11 controls. Asymmetry in the ventral pons or medulla in the area of the corticospinal tracts was noted in seven study patients and one control; one study patient had an enlarged cisterna magna and one an inconclusive (incomplete) study. These findings may support previous studies that have suggested a central nervous system abnormality as a cause of adolescent idiopathic scoliosis.

Surgical treatment of adolescent hallux valgus.

Surgical for adolescent hallux valgus (HV) was performed on 32 feet. Five feet (16%) required revision surgery, and technical errors accounted for recurrence in all five. Satisfaction was obtained in 70% of patients. According to a new bunion rating score, 59% of patients had good to excellent results. In a subgroup of patients treated with metatarsal osteotomy for metatarsus primus varus, the Mitchell osteotomy provided an excellent rating in 95% of patients. Surgery for adolescent HV provides satisfying results in most patients. The one factor most highly correlated with both decreased risk of recurrence of angular deformity and patient satisfaction was a reduction of the intermetatarsal (IM) angle.

Blood loss with total knee arthroplasty.

A substantial drop in blood volume occurs in patients being treated by total knee arthroplasty (TKA). Of 140 TKAs (108 patients) studied to analyze this blood loss, 70 required transfusion and 70 did not. The average transfusion was 2.6 units per arthroplasty. Blood loss in the nontransfused group was 1.8 units per arthroplasty. The overall mean blood loss was 2.2 units per TKA. Insertion of a constrained TKA resulted in a statistically significant increase in blood loss. Preoperative diagnosis, anesthetic technique, revision arthroplasty, patellofemoral arthroplasty, and tourniquet technique did not statistically affect the blood loss. The bulk of the blood loss is collected postoperatively in the suction drainage system.