Management of acute odontoid fractures: operative techniques and complication avoidance

In this article the authors describe the management of Type II odontoid fractures with special attention to operative technique and avoidance of complication. Anterior odontoid screw fixation is a procedure the authors have performed over the last 8 years in cases with acute Type II and rostral Type III odontoid fractures. In cases of Chronic Type II odontoid fractures and in patients with transverse ligament disruption, the authors prefer to undertake posterior transarticular facet screw fixation supplemented by bone graft and interspinous C1-2 wiring. The technical aspects of these procedures are described with a focus on operative nuances. Selection criteria and techniques that the authors have refined over the years have helped them to optimize success rates and minimize complications.

[Transverse fracture of the upper sacrum with major displacement. CT reconstruction: case report]

PURPOSE OF THE STUDY

Transverse fractures of the upper sacrum are rare. We report a case with major displacement and neurological impairment. The use of 3D computed tomography (CT) reconstruction to facilitate preoperative planning and surgical procedure is discussed.

MATERIALS AND METHODS

A 49-year-old depressive woman jumped from the second floor in an attemp to commit suicide. She presented an absence of motor reponse in L5 region on both sides, hypoesthesia of S1 dermatome, perineal problems including saddle hypoesthesia and a hypotonic anal sphincter. Radiologic investigation showed a transverse fracture of the upper sacrum with major displacement. CT with 3D reconstruction visualized the course of the different fracture lines on the different levels of the sacrum. Open reduction, extensive laminectomy and internal fixation were performed 6 days following the injury.

RESULTS

After a 1-year post-operative follow up, complete neurological recovery with normal walking and full perineal sphincter control was observed.

DISCUSSION AND CONCLUSION

Fractures of the upper sacrum with major displacement are exceptional. They require well prepared surgical management. CT series with 3D reconstruction allow an analysis of the course of the different sagittal fracture lines to facilitate surgical planning.

Relationship between impact velocity and injuries in fatal pedestrian-car collisions

The most common type of fatal pedestrian-car collision, i.e. a passenger car with a wedge or pontoon shaped front striking an erect adult with this front, was investigated. A reliable calculation of the impact velocity range by a technical expert and a comprehensive autopsy suitable for traffic accidents were performed in every case. A total of 47 fatalities form the material of this study and the impact velocities varied between 18 and 142 km/h. Primary and secondary injuries did not show a relationship to impact velocity. The occurrence of four types of indirect injuries revealed a clear relationship to impact velocity, i.e. spinal fractures, ruptures of the thoracic aorta, inguinal skin ruptures and dismemberment of the body. Important parameters such as the type of car, impact velocity range and indirect injuries are listed for each individual case. Because of the limited number of cases, the impact velocity ranges (3-30 km/h) instead of mean values were considered. A cautious interpretation of the data can be summarised in the following conclusions: If there is no spinal fracture, the velocity was below 70 km/h and probably below 50 km/h. Aortic and inguinal skin ruptures are always present if the velocity was above 100 km/h but never occurred below 50-60 km/h. If dismemberment occurs, the velocity was above 90 km/h. Consequently, an estimation of the impact velocity from the presence or absence of indirect injuries is possible in pedestrian-car collisions of the type examined. However, the selection criteria applied in this study and additional parameters influencing the collision dynamics have to be considered carefully.

[Lumbar Chance fracture in an child associated with an intra-abdominal lesion]

We report the case of a teenager who was involved in a road traffic accident. She presented a flexion-distraction type of vertebral injury, (Chance fracture). This fracture was associated with an intra-abdominal injury. The child was a passenger in a rear seat using a shoulder seatbelt restraint.

Identification of vertebral deformities in women: comparison of radiological assessment and quantitative morphometry using morphometric radiography and morphometric X-ray absorptiometry

Our aim was to compare normal vertebral reference values for morphometric radiography (MRX) and morphometric X-ray absorptiometry (MXA) and to compare these methods for the identification of vertebral deformities. We calculated MXA reference values (Hologic QDR 4500 A) for 327 women (ages 22-88 years) randomly selected from local General Practice lists in Sheffield, U.K. MRX reference values were calculated from spinal radiographs for 123 of these subjects (ages 56-88 years). We used these reference values to identify deformities in the MRX and MXA reference populations and in 83 women with osteoporosis (ages 49-87 years). We observed differences in mean deformity of vertebral height ratios measured by MRX and MXA, especially for the mid-to-posterior ratio. We compared agreement between quantitative methods (MRX and MXA) and qualitative radiological assessment. Severity of deformity was defined by semiquantitative (SQ) assessment. Agreement was moderate for MRX (k = 0.59; 95% CI = 0.43-0.77) and for MXA (k = 0.47; 95% CI = 0.29-0.66) in the reference population. Agreement was good for MRX (k = 0.86; 95% CI = 0.82-0.89) and MXA (k = 0.71; 95% CI = 0.66-0.75) in the osteoporotic population. MRX and MXA correctly identified a greater proportion of moderate or severe deformities compared with mild deformities. Sensitivity, specificity, predictive values, and accuracy were slightly better for MRX than for MXA. Although MXA agrees well with qualitative radiological assessment, the large proportion of vertebrae excluded from analysis because of poor image quality limits the diagnostic value of the technique. Reference intervals should be technique specific.

Spontaneous interbody fusion after controlled injuries to the spine: an experimental study in rabbits

To evaluate the rationale of spontaneous spine fusion after a spinal injury, the authors conducted an experimental study that consisted of three types of controlled injuries to a rabbit spine model. The first was injury to the intervertebral disk (type I injury). The second was injury of the intervertebral disk along with injury to one of the adjacent vertebral end plates (type II). In type III injury, both the opposing end plates were injured along with the intervertebral disk. In 38 rabbits, a total of 82 injuries of these three types were inflicted. Twenty-six injuries were of type I (n = 22 rabbits), 26 were type II (n = 24 rabbits), and 30 were type III (n = 26 rabbits). Spontaneous fusion occurred only in type III injuries. From the 30 type III injuries, fusion occurred in 20 (66.6%). For an autofusion to occur, both epiphyseal plates may be injured. In the clinical situation, this observation suggests that a radiographically obscure lesion of both neighboring vertebrae may proceed to autofusion of that spinal segment observed later.

Superiority of incremental trauma approach in experimental burst fracture studies

OBJECTIVE

To compare the incremental and single trauma approaches in experimental spinal trauma production.

DESIGN

An in vitro study to produce experimental burst fractures in human spine specimens.

BACKGROUND

Experimental burst fractures have been produced by researchers for various purposes using two approaches: single and incremental traumas. Both the experimental trauma approaches use drop weight technique. There have been no studies to compare these two markedly different methods. Showing clear advantages of one approach over the other may significantly affect the design of future experimental trauma studies, not only of the spine.

METHODS

Using human spine specimens and drop weight technique, burst fractures of varying degrees of severity (defined by canal encroachment) were produced. Impact energies needed for the initial burst fracture and for the progression of the injury, i.e. increased canal encroachment, were studied using regression analyses.

RESULTS

Poor correlation was found between the impact energy and the canal encroachment of the initial burst fracture (R(2)=0.27). A much higher correlation was found when the initial burst fracture points (energy-encroachment) were initialized to zero values and only the progression of the injury was studied (R(2)=0.84, p<0.001). The two regressions represent respectively single and incremental approaches.

CONCLUSIONS

Incremental trauma approach was found to be superior to the single trauma approach, in producing a burst fracture with the desired canal encroachment in the human spine specimens, in spite of their inherent variability in size and strength of human vertebrae.

RELEVANCE

The design of experimental traumas studies will benefit from the results of the present comparative evaluation of single and incremental trauma approaches. The quality of the experiment may be significantly improved.

Cross-sectional area of lumbar vertebrae in peri- and postmenopausal patients with and without osteoporosis

The purpose of this study was to analyze the midvertebral area of lumbar vertebrae in osteoporotic and nonosteoporotic female patients and to find out whether the midvertebral area may be used as an additional parameter in the diagnosis of osteoporosis. In 195 peri- and postmenopausal patients (average age 51.7 +/- 5.2 years) trabecular and cortical bone mineral density (BMD) were determined using quantitative CT (QCT) in L2-4. In addition, midvertebral cross-sectional area was measured in a standardized fashion on the CT sections and the height of the second lumbar vertebra was determined on the lateral digital radiographs. Body height and weight were obtained and vertebral fracture status was determined. According to WHO criteria 29 patients (average age 57.2 years) were considered osteoporotic, 93 osteopenic (average age 52.2 years) and 73 normal (average age 48.6 years). Body weight and size did not show significant differences between the individual groups. Average midvertebral area was 1278 +/- 173 mm2 in the osteoporotic patients, 1186 +/- 125 mm2 in the osteopenic patients and 1126 +/- 127 mm2 in the normals. A correlation of r = -0.39 (p < 0.05) was obtained between BMD and area. Thirty-six of 195 patients showed osteoporotic vertebral fractures. Midvertebral area in these patients was 1266 +/- 171 mm2 versus 1159 +/- 133 mm2 in the nonfractured females (p < 0.05). We therefore conclude that the lumbar midvertebral area is larger in osteoporotic and osteopenic patients compared with women with normal BMD. In contrast to biomechanical considerations midvertebral area seems not to be suited as an additional measure of bone strength in vivo.

Incomplete incorporation of morselized and impacted autologous bone graft: a histological study in 4 intracorporally grafted lumbar fractures

Morselized and impacted bone allografts are used successfully in hip and knee revisions, but experiments using bone chambers indicate that impaction actually can delay ingrowth of new bone into a graft. To understand the remodeling and incorporation process of morselized and impacted grafts, we studied the incorporation of morselized impacted autografts in lumbar fractures histologically. 4 patients were operated on for Th XII-LI fractures. The fractures were stabilized by VSP plates and transpedicular screws in the vertebrae above and below the fractured one. Autologous bone graft was packed into the fractured vertebral body through one of the pedicles. After 18-20 months, the plates were removed and biopsies were obtained from various locations in the fractured vertebra. All fractures were at this time clinically and radiographically healed. Histologically, in all cases, large areas of the autograft in the vertebral body were unvascularized and partially or entirely necrotic. As with morselized bone in hip revisions, evaluation of graft incorporation requires histological examination. Full osseous incorporation of a graft is not always necessary for a good clinical result.

Variation in the posterior vertebral contour line at the level of C-2 on lateral cervical roentgenograms: a method for odontoid fracture detection

As an aid to the assessment of alignment and lordosis, four contour lines can be drawn on the lateral radiograph of the cervical spine. One of these contour lines is the posterior vertebral contour line, in which a smooth, gentle curve, convex anteriorly, is formed by a line drawn along the posterior margins of the cervical vertebral bodies. It is unknown whether discontinuity in the posterior contour line at this level represents a pathologic process of the odontoid. We analyzed the posterior cortex of C-2 and the odontoid in 500 lateral cervical spine radiographs to determine the amount of step-off (deviation from the posterior contour line) seen in normal lateral cervical roentgenograms. Only 15% (n = 75) showed any step-off; none exceeded 3 mm. We recommend that patients presenting with a history of cervical spine trauma who have a step-off at the posterior contour line at the odontoid/C-2 level of > or =3 mm should have fine-cut tomography or multiplanar computed tomography scanning to further assess the odontoid process and rule out fracture.

Craniocervical injuries in judicial hangings: an anthropologic analysis of six cases

Restoration projects and archaeologic excavations in two Canadian prisons resulted in the recovery of the skeletons of six felons executed by judicial hanging. Damage inflicted by hanging on various skeletal elements was observed. Among the injuries seen were fractures of the hyoid cornua, styloid processes, occipital bones, and cervical vertebral bodies (C2) and transverse processes (C1, C2, C3, and C5). Despite the general uniformity of the hanging technique, which involved a subaural knot, the trauma to the skeletal elements and the cause of death varied among individuals. Although some of this variation was probably due to minor differences in hanging practices, individual anatomic peculiarities of the victims likely also contributed.

Vertebral bone mass, size, and volumetric density in women with spinal fractures

Bone densitometry provides a measure of bone mass expressed as bone mineral content (BMC) or areal bone mineral density (aBMD). BMC is unadjusted for bone size while aBMD is adjusted for the projected area of the region scanned but not its depth. Because patients with fractures often have reduced bone size, the deficit in BMC or aBMD relative to controls may be partly the result of the comparison of a smaller bone in patients with fractures with a bigger bone in controls without fractures. We asked, what proportion of the deficit in BMC and aBMD found in women with spine fractures relative to controls is attributable to smaller vertebral size? We measured BMC (g), volume (cm3, derived from projected area3/2), aBMD (g/cm2), and volumetric BMD (vBMD, g/cm3) of the third lumbar vertebra by dual-energy X-ray absorptiometry in 270 premenopausal women aged 18-43 years, 163 postmenopausal women with spine fractures aged 54-83 years, and 209 women without fractures aged 54-87 years. The regression of BMC and aBMD on volume in the premenopausal women was used to calculate volume adjusted BMC and aBMD in postmenopausal women with and without fractures (adjusted BMC = observed BMC + [50 - observed volume] x 0.29; adjusted aBMD = observed aBMD + [50 - observed volume] x 0.0044). The data were expressed in the original units and as standard deviation scores (SD) above or below the young normal mean (T scores) or the age predicted mean (Z scores). All results were expressed as mean +/- SEM. Women with spine fractures had reduced BMC (T = -2.35 +/- 0.07 SD, Z = -1.18 +/- 0.06 SD), volume (T = -1.08 +/- 0.08 SD, Z = -0.82 +/- 0.08 SD), aBMD (T = -3. 06 +/- 0.09 SD, Z = -1.14 +/- 0.06 SD) and vBMD (T = -2.67 +/- 0.10 SD, Z = - 0.94 +/- 0.07 SD) (all p < 0.001). About 48% of the difference in BMC between postmenopausal women with and without spine fractures, and about 16% of the difference in aBMD was explained by the difference in vertebral volume between them. When women with and without spine fractures were intentionally matched by aBMD (and age, height, and weight), vertebral volume was reduced (Z = -0.66 +/- 0.13 SD, p < 0.001). When women with and without fractures were intentionally matched by vertebral volume (and age, height, and weight), vBMD was reduced (Z = -1.07 +/- 0.10 SD, p < 0. 001). Women with spine fractures have smaller vertebrae with less bone in the smaller bone. About half the deficit in BMC relative to controls is due to their smaller bone size. The remainder may be due to reduced bone accrual, increased bone loss, or both. Thus, the pathogenesis of bone fragility is heterogeneous. Factors responsible for a deficit in bone mass (due to reduced accrual or excess bone loss) are unlikely to be identified when reduced bone size exaggerates the deficit, and increased bone size obscures it. Understanding the pathogenesis of bone fragility requires acknowledgment of this heterogeneity and the description of its varied morphological basis. This can be achieved by the study of the periosteal and endosteal surfaces of bone because the absolute and relative changes in these surfaces during growth and aging determine skeletal size, its mass, and architecture.

Osteoporosis with lymphoid nodules and hematopoietic marrow hyperplasia

OBJECTIVE

In 1983 Vigorita reported 3 cases of osteoporosis associated with intramedullary lymphoid nodules. We present 8 patients with osteoporosis and lymphoid nodules (LN) in whom we studied the clinical, biological and histological features and the course of the disease.

METHODS

Three men (mean age 52 yrs., range 43-68 yrs.) and 5 women (mean age 60 yrs., 49-66 yrs.), 6 of them with osteoporosis with fracture and 2 with osteoporosis on bone densitometry (T score < -2.5 SD) were enrolled in this study. The following parameters were studied: immunobinding with IG determination, phosphorus and calcium levels, PTH, 25 and 1-25 OH D3, osteocalcin, urinary deoxypyridinoline, histomorphometry, tests for autoanti-bodies, HIV, HTLV, EBV and CMV serology. The results were compared with those of 20 patients with osteoporosis but without LN. Five patients underwent a second BMB a mean of 2 years after the first.

RESULTS

Five patients had asthenia, 4 had joint pain and 3 had hyperlymphocytosis. Immunologic and virologic investigations were negative in all cases. Bone marrow was hypercellular (59.9 +/- 5.3 vs 40.1 +/- 13%, p: 0.001). At the second BMB, LN were absent but bone marrow was still hypercellular. In all cases, no cause of demineralization was found and osteoporosis progressed rapidly (an average of 3 vertebral compression fractures in three months, with increased resorption (ES 6.5 +/- 1.6 vs 3 +/- 1.2, p: 0.05) with decreased calcification rate (CR 0.62 +/- 0.07 vs 0.79 +/- 0.1, p: 0.04).

CONCLUSION

Some interesting questions are raised by this study. Did an undiscovered viral infection cause the asthenia and joint pain via cytokines or PTHrp in our patients, and can activated lymphocytes perhaps modify bone remodeling?

Pediatric spine fractures

Children have more elastic soft tissue and more potential for remodeling than adults. Certain injuries are unique to children, including posterior limbus injuries, most cases of spinal cord injury without radiographic abnormalities, and spinal trauma in child abuse. This article discusses the pathomechanics, clinical presentation, treatment, and some of the complications of injuries of the thoracolumbar spine in children.

Posterior C1-C2 transarticular screw fixation in the treatment of displaced type II odontoid fractures in the geriatric population--review of seven cases

BACKGROUND

Seven geriatric patients presented with displaced Type II odontoid fractures. All patients underwent a posterior C1-C2 transarticular fixation between November 1994 and December 1996. Ages ranged between 63 and 88 years.

METHODS

Fractures were treated with placement of bilateral transarticular screws, allowing immediate fixation, except in one patient, for whom only a unilateral screw was used. An autograft interspinous strut was also placed, allowing three-point fixation. Mean follow-up was 10.6 months.

RESULTS

Six patients received rigid fixation and developed a stable union. One patient died before any follow-up could be obtained. Two other patients died within 1 year of unrelated causes. The remaining four patients remain active and independent. One intraoperative vertebral artery injury was identified. No clinical sequalae were noted.

CONCLUSION

Posterior transarticular screw fixation is a reasonable option in treating these controversial fractures. Seven geriatric patients tolerated this surgery well, and were mobilized early, avoiding complications related to external immobilization.

Correlation of MR images of disc injuries with anatomic sections in experimental thoracolumbar spine fractures

This cadaver study evaluated the value of MR images for detection of acute intervertebral disc damage associated with fractures of the thoracolumbar spine. Damage to the intervertebral disc may be a major contributor to chronic instability in non-operative treatment or failure of fixation and recurrence of deformity in posterior fixation methods. MR imaging can help us to understand the injury patterns and their prognostic significance. However, before we can justify the use of MRI in clinical cases, determination of MRI's ability to detect acute injury to the disc is necessary. Ten fresh cadaver specimens were used for this study. After obtaining radiograms and MR images, injuries were created with a weight-dropping apparatus using a variety of weights and compression angles. Post-injury radiograms and MR images were taken and the specimens were frozen at -20 degrees C. Slides of these specimens obtained with cryosection techniques were compared with MR images for evaluation of the damage to different parts of the discs. A total of 20 fractures were observed on cryosections. In 12 of the discs adjacent to fractured vertebral bodies, macroscopic damage was seen on the sections. These were all detected on the corresponding MR images. The study showed that MRI is able to detect acute, macroscopic injury to the intervertebral disc. It is therefore justified to use MR for the study of acute disc damage associated with thoracolumbar fractures.

Seat belt fracture with late development of an enterocolic fistula in a child. A case report

STUDY DESIGN

A case report of a 9-year-old boy treated at a pediatric trauma center for a flexion-extension spiral fracture with late development of an enterocolic fistula subsequent to a high-velocity motor vehicle accident.

OBJECTIVES

To increase the awareness of possible delayed bowel complications associated with flexion-distraction injuries of the spine in children.

SUMMARY OF BACKGROUND DATA

Flexion-distraction fractures of the spine in children wearing lap seat belts, so-called "Chance" fractures, are an increasingly common result of high-velocity collisions. This type of fracture, referred to as a seat-belt fracture, is often associated with duodenal or jejunal tears. Although such intra-abdominal injuries are common in such fractures secondary to this type of trauma, the occurrence of an enterocolic fistula has never been reported.

METHODS

A review of all pediatric Chance fractures managed at the Children's Hospital of Eastern Ontario, as well as a literature review of all reported series of flexion-distraction injuries to the spine in children, were performed.

RESULTS

The subtle and prolonged symptomatology of this lesion and its similarity to a cast syndrome is emphasized.

CONCLUSION

Because the orthopedic surgeon is usually the primary care-giver for children with this type of seat-belt trauma, an appreciation of the possibility of a delayed onset enterocolic fistula with its symptomatology is essential to avoid prolonged morbidity.

Classification of thoracolumbar fractures and posterior instrumentation for treatment of thoracolumbar fractures

In treating thoracolumbar injuries, an accurate diagnosis of the structural injury to the spine is critical. I recommend the Allen classification, but all classifications assist in obtaining an accurate understanding of the spine dynamics resulting from the injury. It is essential to remember that the majority of thoracolumbar injuries result from high-energy trauma. It is incumbent upon the spinal surgeon to ensure that multisystem trauma and life-threatening injuries, with the exception of a deteriorating neurologic injury, are cared for before embarking on spinal surgery. Even treatment of these injuries may have to be delayed if cardiovascular or abdominal hemorrhagic injuries take precedence. A critically important piece of information is the neurologic diagnosis. I recommend the ASIA Motor Index as the gold standard for diagnosing injuries and prognosticating outcome. Accurate neurologic diagnosis must be obtained prior to surgery. Finally, I recommend a firm understanding and a good working relationship with the device system used for fixation. Other instructional course authors agree that whether the anterior or the posterior approach is used, familiarity with the device nuances, by not only the surgeon but also the operating team, is very helpful in achieving a successful uncomplicated implantation. If all of the above recommendations are followed, successful outcome and optimal patient recovery can be anticipated in most cases.

Type I osteogenesis imperfecta: diagnostic difficulties

A 65-year-old woman presented with vertebral fractures of the lumbar spine and a history of pathological fractures following minor trauma, which had occurred before the onset of menopause. Her past medical history was significant for intermittent low back pain since childhood, which was attributed to thoracolumbar scoliosis. A diagnosis of unclassifiable osteoporosis was made until invasive diagnostic procedures suggested a mild form of type I osteogenesis imperfecta (OI). In unclear or atypical perimenopausal osteoporosis and diagnosis of OI should be considered.

Bone density reduction in various measurement sites in men and women with osteoporotic fractures of spine and hip: the European quantitation of osteoporosis study

We have measured bone mineral density (BMD) using dual X-ray absorptiometry (DXA) of the spine and hip, spinal quantitative computed tomography (QCTspi), and peripheral radial quantitative computed tomography (pQCTrad) in 334 spine and 51 hip fracture patients. The standardized hip and spine BMD for each patient was calculated and compared with the combined reference ranges published previously, each densitometer having been cross-calibrated with the prototype European Spine Phantom (ESPp) or the European Forearm Phantom (EFP). Male and female fracture cases had similar BMD values after adjusting for body size, where appropriate. This suggests that the relationship between bone density (mass per unit volume) and fracture risk is similar between men and women. However, compared with age-matched controls, mean decreases in BMD ranged from 0.78 SD units (women with hip fracture, DXAspi) to 2.57 SD units (men with spine fractures, QCTspi). The proportion of spine and hip fracture patients falling below the cutoff for osteoporosis (T-score <-2.5 SD) proposed by the World Health Organization (WHO) study group varied according to different BMD measurement procedures (range 18-94%). This finding suggests that the WHO definition requires different thresholds when used with non-DXA BMD measurement techniques. Receiver operator characteristic (ROC) analysis was used to compare measurement techniques for their ability to discriminate between cases and controls. Among DXA sites, the proximal femur was preferred when evaluating generalized bone loss, particularly in elderly people. An additional spinal BMD measurement may add clinical value if spine fracture risk assessment has a high priority. Both axial and peripheral QCT techniques performed comparably to DXA in spinal osteoporosis, so investigators and clinicians may use any of the three technologies with similar degrees of confidence for the diagnosis of generalized or site-specific bone loss providing straightforward clinical guidelines are followed.

High prevalence of osteoporosis in cardiac transplant recipients and discordance between biochemical turnover markers and bone histomorphometry

OBJECTIVE

All patients attending the cardiac transplantation clinic at the Royal Perth Hospital were investigated to determine the prevalence of osteoporosis and to assess changes in bone metabolism and histomorphometry in a cohort of cardiac transplant recipients.

DESIGN

Retrospective cross-sectional study.

PATIENTS

Thirty-two patients (27 male; 5 female) who had received a cardiac transplant during the past 10 years and who were receiving immunosuppressive therapy with cyclosporin, azathioprine and prednisolone were studied.

MEASUREMENTS

All patients had bone densitometry by DEXA of the lumbar spine and femoral neck and X-rays of the thoracolumbar spine. Fasting serum ionized calcium, intact PTH, creatinine, 25 hydroxy-vitamin D, alkaline phosphatase, osteocalcin, testosterone and free thyroxine and urine calcium, creatinine, hydroxyproline and deoxypyridinoline were measured. Six osteoporotic patients consented to transiliac bone biopsy following double tetracycline labelling.

RESULTS

Osteoporosis was present at the lumbar spine in eight patients, femoral neck in seven patients and was present at one or more sites in 13 patients (41%). Seven patients (22%) had vertebral fractures which were asymptomatic in five patients. Secondary hyperparathyroidism was present in 16 patients (53%) but significant renal failure (creatinine clearance < 70 ml/min) was only found in 8 (50%). Levels of biochemical markers of bone turnover were increased in 23 patients (72%). Serum osteocalcin (P = 0.02) and alkaline phosphatase (P = 0.04) were significantly higher in osteoporotic patients than in nonosteoporotic patients. Histomorphometric findings varied markedly between patients. Microscopic features of hyperparathyroidism were not observed.

CONCLUSIONS

Osteoporosis and asymptomatic vertebral fractures are common following cardiac transplantation. Biochemical markers of bone turnover were increased in the majority of patients. Many had biochemical evidence of secondary hyperparathyroidism but this could be attributable to significant renal failure in only 50% of cases. Osteocalcin and alkaline phosphatase correlated inversely with bone density. Histomorphometric findings did not correlate with these biochemical changes in most cases. These results suggest that multiple factors are responsible for osteoporosis in cardiac transplant recipients. Osteocalcin and alkaline phosphatase may be useful biochemical markers, predicting patients at highest risk of fracture.

Defining incident vertebral deformity: a prospective comparison of several approaches. The Study of Osteoporotic Fractures Research Group

Vertebral deformities are common and important outcomes in clinical trials and epidemiologic studies of osteoporosis. While several different methods for defining new deformities have been proposed, it is not clear which is best. We used data from serial spine radiographs obtained an average of 3.7 years apart in 7238 women age >/=65 years from the Study of Osteoporotic Fractures to compare several approaches to defining new deformities by morphometry including a fixed percentage reduction in any vertebral height (FIXED%), a change in a summary spinal deformity index, a change in a vertebra from no prevalent deformity at baseline to a deformity at follow-up, as well as several variations of these methods. We compared results of each definition with several clinical correlates, including height loss, back pain, age, baseline bone mineral density, and the presence of a baseline deformity. We also estimated the sample size required for a clinical trial using various cut points. At a given level of incidence, all methods had similar relationships with each of the correlates. Given that similarity, the FIXED% method was simplest and needed no reference data. Using the FIXED% method, a 20-25% vertebral height reduction criterion for deformity maximized the power for a clinical trial. We conclude that all of the morphometric approaches to defining incident deformities have similar relationships to clinical correlates of vertebral deformity, but that use of a fixed percentage reduction in vertebral height is the simplest and most practical. For the FIXED% method, a 20-25% reduction in vertebral height minimizes the sample size required for clinical trials and epidemiologic studies.

Number and type of vertebral deformities: epidemiological characteristics and relation to back pain and height loss. European Vertebral Osteoporosis Study Group

Vertebral deformity is the classical hallmark of osteoporosis. Three types of vertebral deformity are usually described: crush, wedge and biconcave deformities. However, there are few data concerning the descriptive epidemiology of the individual deformity types, and differences in their underlying pathogenesis and clinical impact remain uncertain. The aim of this study was to compare the epidemiological characteristics of the three types of vertebral deformity and to explore the relationships of the number and type of deformity with back pain and height loss. Age-stratified random samples of men and women aged 50 years and over were recruited from population registers in 30 European centers (EVOS study). Subjects were invited to attend for an interviewer-administered questionnaire and lateral spinal radiographs. The presence, type and number of vertebral deformities was determined using the McCloskey-Kanis algorithm. A total of 13,562 men and women were studied; mean age in men was 64.4 years (SD 8.5), and in women 63.8 years (SD 8.5 years). There was evidence of variation in the occurrence of wedge, crush and biconcave deformity by age, sex and vertebral level. Wedge deformities were the most frequent deformity and tended to cluster at the mid-thoracic and thoraco-lumbar regions of the spine in both men and women. Similar predilection for these sites was observed for crush and to a lesser extent biconcave deformities though this was much less marked than for wedge deformities. In both sexes the frequency of biconcave deformities was higher in the lumbar than the thoracic spine and unlike the other deformity types it did not decline in frequency at lower lumbar vertebral levels. The prevalence of all three types of vertebral deformity increased with age and was more marked in women. There were no important differences in the effect of age on the different deformity types. All types of deformity were associated with height loss, which was greatest for individuals with crush deformity. Back pain was also associated with all types of deformity. Overall, these results do not suggest important differences in pathophysiology between the three deformity types. Biomechanical factors appear to be important in determining their distribution within the spine. All deformity types are linked with adverse outcomes, though crush deformities showed greater height loss than the other deformity types.