In vivo three-dimensional morphometric analysis of the lumbar pedicle isthmus.

STUDY DESIGN: In vivo noninvasive study. OBJECTIVE: To properly quantify pedicle anatomic parameters, using subject-based CT three-dimensional models and compare the data from 2-dimensional transverse-CT images. SUMMARY OF BACKGROUND DATA: Accurate measurement of morphometric parameters of pedicle isthmus is important for transpedicular procedures. Anatomically, the lumbar pedicle is known to be elliptical cross-sectionally and slightly inclined in the vertical plane in the lower lumbar levels. Therefore, measurement of the pedicle isthmus may be overestimated when transverse images are used. More accurate measurement of the 3-dimensional geometry of the pedicle is therefore needed. To the best of our knowledge, 3-dimensional geometry of the pedicle has not been reported as the literature values are based on 2-dimensional image data. METHODS: In vivo measurements of the lumbar pedicle isthmus were performed on the 3-dimensional subject-based CT models, using custom-developed software in 89 volunteers. RESULTS: The least axis of pedicle, the longest axis of pedicle and the transverse plane width were largest at L5 in both genders. The isthmus angle declined in the lower levels. The ratio of the transverse plane width to the least axis of pedicle was largest at L5. CONCLUSION: Our results showed that the least axis of pedicle, the longest axis of pedicle and the transverse plane width peaked at L5, and the transverse plane width became approximately twice as long in the lower levels compared to the upper levels. The ratio of the transverse plane width to the least axis of pedicle increased by about 40% at L5. These findings highlight the fact that measuring the isthmus width from CT transverse images leads to overestimation, especially in the lower lumbar spine. Therefore, a 3-dimensional inclination of the least axis of the pedicle should be taken into account for the determination of the pedicle diameter in the lower lumbar vertebrae.

Prospective study of iliac crest bone graft harvest site pain and morbidity.

BACKGROUND CONTEXT: Morbidity associated with autologous bone graft harvest is an important factor in determining the utility of expensive alternatives such as recombinant bone morphogenic protein. The most frequently reported complication associated with graft harvest is chronic pain. PURPOSE: To prospectively determine the degree of pain and morbidity associated with autologous iliac crest bone graft harvest and its effect on activities of daily living. STUDY DESIGN: Prospective observational cohort study. PATIENT SAMPLE: One hundred ten adult patients undergoing elective posterior lumbar spinal fusion surgery involving autologous iliac crest bone graft harvest. OUTCOME MEASURES: Patient self-reported Visual Analog Scale (VAS) scores for pain and a study-specific questionnaire regarding activities of daily living. METHODS: One hundred ten patients were prospectively enrolled. Postoperative VAS scores (0-100) for harvest site pain were obtained at 6-week, 6- and 12-month follow-up. Patients completed a 12-month questionnaire regarding the persistence of specific symptoms and resulting limitation of specific activities. RESULTS: One hundred four patients were available for 1-year follow-up. Mean VAS pain scores (scale 0-100) at 6 weeks, 6 and 12 months were 22.7 (standard deviation [SD], 25.9), 15.9 (SD, 21.5), and 16.1 (SD, 24.6), respectively. At 12 months, 16.5% reported more severe pain from the harvest site than the primary surgical site, 29.1% reported numbness, and 11.3% found the degree of numbness bothersome, whereas 3.9% were bothered by scar appearance. With respect to activity limitations resulting from harvest site pain at 1 year, 15.1% reported some difficulty walking, 5.2% with employment, 12.9% with recreation, 14.1% with household chores, 7.6% with sexual activity, and 5.9% irritation from clothing. CONCLUSIONS: There is a significant rate of persistent pain and morbidity from iliac crest bone graft harvest when associated with elective spine surgery. Mean pain scores progressively decline over the first postoperative year. Nevertheless, harvest site pain remains functionally limiting in a significant percentage of patients 1 year after surgery. Rates of functional limitation are higher than previously reported and may be because of increased sensitivity of the prospective study design and targeted investigation of these specific symptoms. Validity of these findings is necessarily limited by patient ability to discriminate harvest site pain from alternative sources of back and buttock pain.

Isolated radial shaft fractures are more common than Galeazzi fractures.

PURPOSE: In contrast to isolated diaphyseal fractures of the ulna (so-called night-stick fractures), isolated fractures of the radial diaphysis generally are expected to have associated injury of the distal radioulnar joint (DRUJ), the so-called Galeazzi fracture. This study retrospectively reviewed isolated fractures of the radial diaphysis in a large cohort of patients to determine how often such fractures occur without DRUJ injury METHODS: Thirty-six patients with fracture of the radius without fracture of the ulna were followed up for at least 6 months after injury. Injury of the DRUJ was defined as more than 5 mm of ulnar-positive variance on radiographs taken before any manipulative or surgical reduction. All of the fractures were treated with plate and screw fixation (8 with autogenous bone grafting) and all healed. Patients with DRUJ injury had either temporary pinning or immobilization of the DRUJ or surgical fixation of a large ulnar styloid fracture. Patients without DRUJ injury were mobilized within 2 weeks. RESULTS: Nine patients had dislocation of the DRUJ, 4 with large ulnar styloid fractures. Among the remaining 27 patients 1 had displacement of the proximal radioulnar joint noted after surgery, leading to a secondary procedure for radial head resection. The functional results were satisfactory or excellent in all but 2 patients with functional limitations related to central nervous system injury. No patient had DRUJ dysfunction at the final follow-up evaluation. CONCLUSIONS: Isolated fractures of the radial diaphysis are more common than true Galeazzi fractures. Surgeons should take great care not to overlook injury to the distal or proximal radioulnar joint in association with isolated diaphyseal fractures of the radius; however, fractures without identifiable radioulnar disruption can be treated without specific treatment of the DRUJ and with immediate mobilization. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Comminuted diaphyseal fractures of the radius and ulna: does bone grafting affect nonunion rate?

BACKGROUND: The recommendation of Anderson and colleagues to bone graft even relatively minor amounts of comminution (a third of the bone diameter) in the treatment of diaphyseal forearm fractures with plate-and-screw fixation has been questioned. This study examines factors related to nonunion in adult patients with comminuted diaphyseal fractures of both the radius and the ulna to determine the relative influence of bone grafting. METHODS: Over a 15-year period at two hospitals, 41 patients with diaphyseal fractures of both forearm bones satisfied the following criteria: comminution (Orthopaedic Trauma Association grade IV or higher) of at least one fracture; treatment with 3.5- or 4.5-mm dynamic compression plates at least six holes in length; and minimum 12-month follow-up. Multiple logistic regression was used to determine the contribution of the following factors to the risk of nonunion: multiple injuries; ipsilateral upper extremity injury; open wound; and the application of cancellous bone graft at the fracture site. RESULTS: Five patients had nonunion of one or both bones (12%). According to the multiple logistic regression model, none of the factors studied had a statistically significant association with nonunion (p > 0.40 for all). The odds ratios were as follows: multiple injuries, 2.1 (95% confidence interval [CI], 0.34-12.9); ipsilateral injury, 0.68 (95% CI, 0.058-7.84); open fracture, 1.46 (95% CI, 0.21-9.89); and bone graft, 0.98 (95% CI, 0.15-6.42). CONCLUSION: Nonunion occurred in 12% of comminuted, diaphyseal fractures of both bones of the forearm treated with dynamic compression plates. No single factor was associated with nonunion. In particular, the use of bone graft was not associated with a higher rate of union.