Limb-length discrepancy measured with computerized axial tomographic equipment

The Comparison of Lower Extremity Length and Angle between Computed Radiography-Based Teleoroentgenogram and EOS® Imaging System

Background and objectives: The differences between computed radiography-based teleoroentgenograms (CR-based teleoroentgenograms) and an EOS® imaging system were evaluated by measuring lower extremity lengths and alignments. Materials and methods: The leg length [L], femur length [F], tibia length [T], and hip−knee−ankle (HKA) angle were measured in 101 patients with lower extremity disease by a CR-based teleoroentgenogram with computed radiography and an EOS®. The additive length of the femoral and tibial segments (F + T) was determined by adding the two length values. Then, the differences among all five parameters between the two techniques were analyzed. The magnification (mm) was calculated by subtracting the length measurements on the EOS® from those in the scanogram. Furthermore, the magnification percentage (%) was calculated by dividing the magnification with the measurements on the EOS®. Results: The magnification errors (mean ± standard deviation), when comparing both right and left sides, were 7.80 ± 1.41%, 7.3 ± 6.01%, 5.16 ± 1.25%, and 6.45 ± 0.94% for L, F, T, and F + T, respectively. For limb length, the CR-based teleoroentgenogram had an average magnification of 6.8% (range, 5.2 to 7.8%) compared to the EOS® imaging. The two groups displayed a statistical difference (p < 0.01), except for the HKA angle. Conclusions: The CR-based teleoroentgenogram had a magnification of about 6.8% compared to the EOS® imaging system in evaluating lower extremity length. Therefore, more attention must be given to CR-based teleoroentgenograms to correct angular deformities.

Computed Tomography in Limb Salvage and Deformity Correction-3D Assessment, Indications, Radiation Exposure, and Safety Considerations

Computed tomography (CT) is an essential tool in orthopedic surgery but is known to be a method with that entails radiation exposure. CT increases the risk of developing fatal cancer, which should not be underestimated. However, patients with bone defects and/or deformities must frequently undergo numerous investigations during their treatment. CT is used for surgical planning, evaluating callus maturation, alignment measurement, length measurement, torsion measurement, and angiography. This study explores the indications in CT scans for limb lengthening and deformity correction and estimates the effective radiation dose. These results should help avoid unnecessary radiation exposure by narrowing the examination field and by providing explicit scanning indications. For this study, 19 posttraumatic patients were included after the bone reconstruction of 21 lower limbs. All patients underwent CT examinations during or after treatment with an external ring fixator. The mean effective dose was 3.27 mSv, with a mean cancer risk of 1:117,014. The effective dose depended on the location and indication of measurement, with a mean dose of 0.04 mSv at the ankle up to 6.8 mSv (or higher) for vascular depictions. CT evaluation, with or without 3D reconstruction, is a crucial tool in complex bone reconstruction and deformity treatments. Therefore, strict indications are necessary to reduce radiation exposure-especially in young patients-without compromising the management of their patients.

Incidence of Leg-Length Discrepancy After Index Hinge Total Knee Arthroplasty

BACKGROUND

Leg-length discrepancies are not commonly associated with total knee arthroplasty (TKA); however, hinge TKA is a complex form of knee reconstruction where functionality of all knee ligaments is replaced by the TKA construct. The purpose of this study is to evaluate the incidence of leg-length discrepancies after unilateral index hinge TKA and association with patient outcomes.

METHODS

A retrospective review was performed of all patients who underwent unilateral index hinge TKA at a single academic institution from 1999 to 2019. Among 671 patients who underwent index hinge TKA, 188 (28%) had full-length standing anteroposterior hip-to-ankle radiographs available for review both preoperatively and postoperatively. All patients with a leg-length change ≥2 cm were also contacted with a standardized questionnaire to assess for complications. The mean age was 65 years, the mean body mass index was 33 kg/m², and 52% were female. The mean number of prior surgeries was 2 (range, 0-12).

RESULTS

The absolute mean and median change in leg lengths was 20 mm and 13 mm, respectively (range, 0-130 mm). Lengthening occurred in 119 (63%) patients compared with shortening in 69 (37%) patients. An absolute change in leg lengths ≥1 cm was observed in 109 (58%) patients, ≥2 cm in 63 (34%) patients, and ≥5 cm in 15 (8%) patients.

CONCLUSION

Large changes in the leg length are common after hinge TKA, likely secondary to altered soft-tissue constraints. Surgeons should be cognizant of potential changes in the leg length in the setting of hinge TKA and incorporate this into preoperative planning and patient counseling.

LEVEL OF EVIDENCE

Level IV, therapeutic.

Precision and Accuracy of Measurements on CT Scout View

OBJECTIVES

The purposes of this study were to (1) investigate the limits of measurements on scout view in three computed tomography axes, x, y and z and (2) develop a model to provide better understanding of measurement accuracy.

METHODS

For the first objective, anteroposterior and lateral scout views of a Catphan phantom 200 mm in diameter and length were acquired with a GE scanner at 21 different table heights. Phantom measurements on scout view were performed by two experienced readers. The comparison of their measures provided estimation of precision. The accuracy was assessed by determining the bias, calculated as the difference between the values measured on scout view and the real phantom size. Second, a model was developed investigating the relationship between the dimensions of the object, its image, and the table height. This relationship was tested on our data.

RESULTS

Scout view measurements were precise, with less than 0.53% difference between readers. In addition, small biases of about 1 mm were detected in the z-axis, whatever the table height. In the other axes, serious biases from -13 to +73 mm were measured. Furthermore, at isocentre, overestimations up to 7 mm were shown. The results also indicated that biases in scout view measurements are because of the geometrical projection related to the object-detector distance.

CONCLUSIONS

Measurements in the table movement axis are precise and accurate, conferring to scout views an added value for preoperative planning in orthopedic surgery.

Measuring limb length discrepancy using pelvic radiographs: the most reproducible method

Leg length inequality following total hip replacement remains common. In an effort to reduce this occurrence, surgeons undertake pre-operative measurements, templating and use various forms of intraoperative measurements, including computer navigation. This study aims to delineate which measurement technique is most appropriate for measuring leg length inequality from a pelvic radiograph. Three observers took a total of 9600 measurements from 100 pelvic radiographs. Four lines were constructed on each of the radiographs, bisecting the acetabular teardrops, ischial spines, inferior sacroiliac joint and inferior obturator foramen. Measurements were taken from these lines to the most prominent medial point on the lesser trochanter and to the tip of the greater trochanter. The effect of pelvic positioning was also assessed using radiographs of a synthetic pelvis and femur. Intra-observer and inter-observer variability were calculated. Measuring from the inferior aspect of the ischial tuberosities to the most prominent medial point on the lesser trochanter appears to be the best method for measuring LLD however large error margin still exist, even when corrected for magnification errors.

Association between leg length discrepancy and posterior tibial tendon dysfunction

BACKGROUND

Leg length discrepancy (LLD) is associated with a variety of orthopaedic disorders and biomechanical gait changes that involve possible overload of the posterior tibial tendon (PTT). In view of the biomechanical disturbances induced by LLD, an association may exist between LLD and PTT dysfunction (PTTD).

PURPOSE

To compare the frequency and magnitude of LLD between subjects with and without PTTD and ascertain whether associations exist between clinical features and presence of dysfunction.

STUDY DESIGN

Case-control study.

METHODS

A total of 118 patients with a diagnosis of PTTD were seen between January 2009 and September 2012 and compared with 118 gender-matched and race-matched volunteers. The frequency of LLD, the mean absolute LLD, and the mean relative LLD were measured by conventional (radiographic) or computed tomography scanography and compared between cases and controls.

RESULTS

The prevalence of LLD and mean absolute and relative LLD values were significantly greater in the case group (94.9%, 5.64 mm and 7.36%, respectively) than in the control group (79.7%, 3.28 mm and 4.18%, respectively) (P < .001).

CONCLUSION

The findings of this study demonstrate a relationship between LLD and PTTD. In light of the major biomechanical changes it induces, LLD may be a predisposing factor for development of PTTD.

EOS low-dose radiography: a reliable and accurate upright assessment of lower-limb lengths

BACKGROUND

Children with lower-limb-length discrepancy require repeated radiographic assessment for monitoring and as a guide for management. The need for accurate assessment of length and alignment is balanced by the need to minimize radiation exposure. We compared the accuracy, reliability, and radiation dose of EOS, a novel low-dose upright biplanar radiographic imaging system, at two different settings, with that of conventional radiographs (teleoroentgenograms) and computed tomography (CT) scanograms, for the assessment of limb length.

METHODS

A phantom limb in a standardized position was assessed ten times with each of four different imaging modalities (conventional radiographs, CT scanograms, EOS-Slow, EOS-Fast). A radiation dosimeter was placed on the phantom limb, on a portion closest to the radiation source for each modality, in order to measure skin-entrance radiation dose. Standardized measurements of bone lengths were made on each image by consultant orthopaedic surgeons and residents and then were assessed for accuracy and reliability.

RESULTS

The mean absolute difference from the true length of the femur was significantly lower (most accurate) for the EOS-Slow (2.6 mm; 0.5%) and EOS-Fast (3.6 mm; 0.8%) protocols as compared with CT scanograms (6.3 mm; 1.3%) (p &lt; 0.0001), and conventional radiographs (42.2 mm; 8.8%) (p &lt; 0.0001). There was no significant difference in accuracy between the EOS-Slow and EOS-Fast protocols (p = 0.48). The mean radiation dose was significantly lower for the EOS-Fast protocol (0.68 mrad; 95% confidence interval [CI], 0.60 to 0.75 mrad) compared with the EOS-Slow protocol (13.52 mrad; 95% CI, 13.45 to 13.60 mrad) (p &lt; 0.0001), CT scanograms (3.74 mrad; 95% CI, 3.67 to 3.82 mrad) (p &lt; 0.0001), and conventional radiographs (29.01 mrad; 95% CI, 28.94 to 29.09 mrad) (p &lt; 0.0001). Intraclass correlation coefficients showed excellent (&gt;0.90) agreement for conventional radiographs, the EOS-Slow protocol, and the EOS-Fast protocol.

CONCLUSIONS

Upright EOS protocols that utilize a faster speed and lower current are more accurate than CT scanograms and conventional radiographs for the assessment of length and also are associated with a significantly lower radiation exposure. In addition, the ability of this technology to obtain images while subjects are standing upright makes this the ideal modality with which to assess limb alignment in the weight-bearing position. This method has the potential to become the new standard for repeated assessment of lower-limb lengths and alignment in growing children.

CLINICAL RELEVANCE

This study assesses the reliability and accuracy of a diagnostic test used for clinical decision-making.

Reliability of a new method for lower-extremity measurements based on stereoradiographic three-dimensional reconstruction

INTRODUCTION

Several clinical and radiological techniques have been described to assess lower limb length and angle measurements. None of them has yet met the ideal criteria for a reliable, reproducible, safe, and inexpensive system. In this context, a new biplanar X-ray system (EOS™, EOS imaging, Paris, France) makes it possible to obtain a 3D reconstruction of the lower extremities from two 2D orthogonal radiographic images, with associated calculation of 3D measurements. The reliability of this technique has never been documented on adults.

HYPOTHESIS

Lower limb measurements produced by the 3D EOS™ reconstruction system are reproducible regarding inter- and intraobserver assessment and more reliable with this 3D technique than when they are obtained from 2D measurements.

MATERIALS AND METHODS

This study included 25 patients awaiting total hip arthroplasty (50 lower limbs). Two independent observers made all measurements twice, both on the 2D frontal radiograph and using 3D reconstructions (femoral measurements of length, offset, neck shaft angle, neck length, and head diameter, as well as the tibia length, limb length, HKA and HKS). Reproducibility was estimated by intraclass correlation coefficients.

RESULTS

Both the inter- and intraobserver reproducibility of the EOS™ measurements was excellent; more specifically inter- and intraobserver reproducibility was 0.997 and 0.997 for femoral length, 0.996 and 0.995 for tibial length, 0.999 and 0.999 for limb length, 0.894 and 0.891 for HKS, 0.993 and 0.994 for HKA, 0.870 and 0.845 for femoral offset, and 0.765 and 0.851 for neck shaft angle. For most of the variables, the interobserver correlations were statistically better with the EOS™ 3D reconstruction.

DISCUSSION

Our results show that the EOS™ systems allow reproducible lower limb measurements. Furthermore, 3D EOS™ reconstructions offer better reproducible measures for most of the parameters than radiographic 2D projection. Its use before deciding on surgery and during planning for lower limb arthroplasty appears essential to us.

LEVEL OF EVIDENCE

Level III: diagnostic prospective study on consecutive patients.

Measurement of leg length discrepancy after total hip arthroplasty. The reliability of a plain radiographic method compared to CT-scanogram

OBJECTIVE

To measure the interobserver reliability and intraobserver reproducibility of post total hip arthroplasty (THA) leg length discrepancy (LLD) measurement on radiographs as well as to evaluate its accuracy by comparing it with LLD measurement on computed tomographic scanogram (CT-scanogram).

MATERIALS AND METHODS

In this prospective study, postoperative LLD measurements in ten THA patients were made by four observers on anteroposterior radiographs of the pelvis (inter-teardrop line to the tip of lesser trochanter) and compared to LLD measurements made on CT-scanogram scout views of the lower limb. Two observers repeated the LLD measurements on radiographs 8 weeks after the first measurements. The interobserver reliability of the LLD measurement on plain radiographs was evaluated by comparing the measurements of the four observers and the intraobserver reproducibility by comparing the two repeated measurements made by the two observers.

RESULTS

We found excellent interobserver reliability (mean ICC 0.83) and intraobserver reproducibility (ICC 0.90 and 0.88) of the LLD measurements on plain radiographs. There was a moderate to excellent agreement, but with wide variation of measurements among the four observers, when plain radiographic measurement was compared with CT-scanogram (ICC 0.58, 0.60, 0.71, and 0.82).

CONCLUSION

Despite the excellent interobserver reliability and intraobserver reproducibility of LLD measurement on radiographs, clinicians should be aware of its limited accuracy when compared to CT-scanogram.

Percutaneous intradiscal aspiration of a lumbar vacuum disc herniation: a case report

We report a case of an 83-year-old gentleman presenting with acute low back pain and radicular left lower extremity pain after golfing. A magnetic resonance imaging (MRI) of the lumbar spine revealed a low-signal-density lesion compressing the L5 nerve. A computed tomography scan was then ordered, confirming an extra-foraminal disc protrusion at the L5-S1 level, containing a focus of gas that was compressing the left L5 nerve root and communicating with the vacuum disc at L5-S1. After a failed left L5 transforaminal epidural steroid injection, the patient was brought back for a percutaneous intradiscal aspiration of the vacuum disc gas. This resulted in immediate relief for the patient. A follow-up MRI performed 2 months after the procedure found an approximate 25% reduction in the size of the vacuum disc herniation. Six months after the procedure, the patient remains free of radicular pain. This case report suggests that a percutaneous aspiration of gas from a vacuum disc herniation may assist in the treatment of radicular pain.

The reliability of computed tomography scanograms in the measurement of limb length discrepancy

This study determined the intrarater and interrater reliabilities of measurements of paediatric limb length discrepancy on anteroposterior scout computed tomography scanograms. Seven physicians measured 26 films at two measuring sessions, separated by at least 8 weeks. High intraclass correlation coefficients above 0.96 were observed for measures by different raters within one session and also for repeat measures by the same raters across sessions. The intrarater, intersessional 95% limits of agreement were +/-6 mm for tibial length, +/-5 mm for femoral length and +/-7 mm for total limb length. These errors are similar to those seen with the use of orthoroentgenograms.

Methods for assessing leg length discrepancy

The use of accurate and reliable clinical and imaging modalities for quantifying leg-length discrepancy (LLD) is vital for planning appropriate treatment. While there are several methods for assessing LLD, we questioned how these compared. We therefore evaluated the reliability and accuracy of the different methods and explored the advantages and limitations of each method. Based on a systematic literature search, we identified 42 articles dealing with various assessment tools for measuring LLD. Clinical methods such as use of a tape measure and standing blocks were noted as useful screening tools, but not as accurate as imaging modalities. While several studies noted that the scanogram provided reliable measurements with minimal magnification, a full-length standing AP computed radiograph (teleoroentgenogram) is a more comprehensive assessment technique, with similar costs at less radiation exposure. We recommend use of a CT scanogram, especially the lateral scout view in patients with flexion deformities at the knee. Newer modalities such as MRI are promising but need further investigation before being routinely employed for assessment of LLD.

LEVEL OF EVIDENCE

Level IV, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Leg length discrepancy in total hip arthroplasty: comparison of two methods of measurement

Measurement of leg length discrepancy is an important part in planning a successful total hip arthroplasty (THA). Many clinical and radiological methods with variable degrees of accuracy have been advocated to carry out this measurement. We studied the accuracy of a commonly used clinical method by comparing it to a well-known and reliable radiological method. A total of 139 patients aged 44-89 (mean: 67.5 years) scheduled to undergo THA were examined for clinical and radiological leg length discrepancy measurements before and after the operation by the same observers. There was a poor correlation between the clinical and radiological methods preoperatively [r = 0.21, intra-class correlation coefficient (ICC) = 0.33]. The correlation was better postoperatively (r = 0.45, ICC = 0.62). The clinical method used is not recommended for leg length discrepancy measurement preoperatively. Caution should even be taken when using this method postoperatively. The authors recommend using the radiological method when measuring leg length discrepancy as a part of planning for THA.

Advances in management of limb length discrepancy and lower limb deformity

PURPOSE OF REVIEW

Limb length discrepancy and lower extremity angular deformity are among the most common nontraumatic conditions in children for which orthopedic referral is sought. There are a number of developments in the surgical management of these problems which have facilitated and improved the quality of care of affected individuals.

RECENT FINDINGS

In recent years, we have developed an improved understanding of ramifications of limb length discrepancy on gait. New treatment options for both limb length discrepancy and deformity include the method of 'guided growth' using small, extraphyseal plates. External fixator technology continues to improve, allowing correction of limb length discrepancy and angular and rotational deformities simultaneously.

SUMMARY

The development of these techniques for the treatment of limb length discrepancy and angular deformity has expanded the indications for surgical management and decreased the incidence and severity of potential complications.

Reliability analysis for radiographic measurement of limb length discrepancy: full-length standing anteroposterior radiograph versus scanogram

Patients with limb length discrepancy (LLD) often have associated angular deformities requiring a standing full-length radiograph of the lower limb in addition to a scanogram. The purpose of our study was to determine the intraobserver and interobserver reliability of measuring LLD with both techniques, using computed radiography. The LLD was measured on 70 supine scanograms and standing anteroposterior radiographs of the lower extremity by 5 blinded observers on 2 separate occasions. Intraclass correlation coefficient (ICC) and mean absolute difference (in millimeters) was calculated to assess intraobserver and interobserver reliability and found to be excellent for both radiographic techniques. Intraobserver ICC and mean absolute difference was 0.975 to 0.995 and 1.5 to 2.6 mm for scanogram and 0.939 to 0.996 and 1.5 to 4.6 mm for the standing radiograph, respectively. Repeated measurements for both radiographic studies were within 5 mm of the first measurement greater than 90% and within 10 mm greater than 95% of times. Interobserver ICC and mean absolute difference was 0.979 and 2.6 mm for scanogram and 0.968 and 3.0 mm for the standing radiograph. The reliability was excellent irrespective of age, sex, and underlying diagnosis other than Blount disease, which had good reliability. A standing anteroposterior radiograph of the lower extremity should be the imaging modality of choice when evaluating patients with limb length inequality who may have angular deformities because it allows a comprehensive evaluation of the extremity and is as reliable as a scanogram for measuring LLD. This approach may decrease the radiation exposure and financial burden involved in assessing patients with unequal limb lengths.

Reliability and accuracy of MRI scanogram in the evaluation of limb length discrepancy

The purpose of this study was to compare MRI scanogram with traditional radiographic methods for measurement of limb length. The authors hypothesized that MRI scanogram would be as reliable and accurate as radiographic scanogram in measurement of limb length without exposing patients to ionizing radiation. Twelve cadaveric femurs were measured using AP conventional radiographic scanogram, CT scanogram, MRI scanogram, and electronic caliper. Three orthopaedists performed two separate measurements using each technique. Intraobserver and interobserver variability was assessed for each of the three radiographic techniques. Accuracy was assessed by comparison of radiographic measurements to electronic caliper measurements of femur length. The reliability of all three radiographic limb length measurement techniques was excellent (ICC > 0.99). The accuracy of plain radiographic scanogram was slightly superior to CT scanogram and MRI scanogram. The mean absolute differences for radiographic, CT, and MRI scanograms compared with the gold standard, direct caliper measurement, were 0.52 mm, 0.68 mm, and 2.90 mm, respectively. All three scanogram techniques showed excellent reliability and accuracy. Radiographic scanogram remains the gold standard for leg length measurement. MRI scanogram is slightly less accurate compared with radiographic scanogram, but it does not use ionizing radiation. MRI scanogram merits clinical study and comparison with the traditional radiographic scanogram method for measurement of limb length.

Measurement variance in limb length discrepancy: clinical and radiographic assessment of interobserver and intraobserver variability

The purpose of this study was to assess interobserver and intraobserver variability in the assessment of clinical and radiographic measurement of lower limb length discrepancy. Clinical measurements included direct measurement with a tape measure from anterior superior iliac spine (ASIS) to lateral malleolus and ASIS to medial malleolus as well as block measurement. Slit scanogram radiographic measurement was also evaluated. All three clinical measurements had excellent reliability, but the relatively large mean differences and the large 95% confidence intervals for clinical measurements limit the usefulness of these techniques. Slit scanogram measurement was the most reliable measurement technique. The intraobserver variance of direct slit scanogram measurement included intraclass correlation coefficient of 0.99, mean difference of 0.1 cm, and 95% confidence interval of 0.4 cm. Results were not influenced by patient age or body mass index. Slit scanogram measurement is the preferred method for assessment of limb length discrepancy. The direct slit scanogram measurement described in the text follows the mechanical axis line of the leg in the "at ease" standing position described by Paley. Direct measurement using a measuring tape on a full-length slit scanogram is more reliable than indirect measurement using horizontal lines drawn to a radiolucent ruler that is positioned by a technician, since direct measurement avoids errors due to nonparallel positioning of the limb relative to the ruler, and direct measurement also avoids errors due to non-horizontal lines drawn from standard bony landmarks to the ruler. The ideal radiographic measurement technique would have high reliability and accuracy and would minimize or eliminate radiation.

Should full-length standing anteroposterior radiographs replace the scanogram for measurement of limb length discrepancy?

The orthoroentgenogram, commonly known as the 'scanogram', continues to be the most widely used imaging technique for measuring limb length discrepancy (LLD). This study reviews other methods of measuring LLD including full-length standing anteroposterior radiographs, computed tomography/digital localization image, and microdose digital scanography. We present seven cases that demonstrate the pitfalls of scanograms as compared with full-length standing anteroposterior radiographs. Illustrative cases provide the rationale for the clinician managing LLD on a regular basis to utilize full-length standing anteroposterior radiographs as the instrument that will provide the most clinically relevant information.

Lumbar disc degeneration: epidemiology and genetic influences

STUDY DESIGN

A literature review.

OBJECTIVE

To synthesize the scientific literature on the prevalence of lumbar disc degeneration and factors associated with its occurrence, including genetic influences.

METHODS

A literature review was conducted of the prevalence of disc degeneration. Studies of the etiology of disc degeneration were summarized, with particular attention given to studies of genetic influences.

RESULTS AND CONCLUSIONS

There are extreme variations in the reported prevalence of specific degenerative findings of the lumbar spine among studies, which cannot be explained entirely by age or other identifiable risk factors (e.g., prevalence figures for disc narrowing varied from 3% to 56%). It is likely that these variations are due, in great part, to inconsistencies in case definitions and measurements, which are impeding epidemiologic research on disc degeneration. Research conducted over the past decade has led to a dramatic shift in the understanding of disc degeneration and its etiology. Previously, heavy physical loading was the main suspected risk factor for disc degeneration. However, results of exposure-discordant monozygotic and classic twin studies suggest that physical loading specific to occupation and sport has a relatively minor role in disc degeneration, beyond that of upright postures and routine activities of daily living. Recent research indicates that heredity has a dominant role in disc degeneration, explaining 74% of the variance in adult populations studied to date. Since 1998, genetic influences have been confirmed by the identification of several gene forms associated with disc degeneration.

Familial predisposition for lumbar degenerative disc disease. A case-control study

STUDY DESIGN

A case-control study using magnetic resonance imaging and plain radiography to evaluate whether a family history of lumbar disc herniation is a risk factor for disc degeneration.

OBJECTIVES

To evaluate the significance of a family history of operated lumbar disc herniation in the development of lumbar disc degeneration and lumbar disc herniation.

SUMMARY OF BACKGROUND DATA

There are only a few epidemiologic studies indicating that a family history of intervertebral disc herniation is a risk factor for juvenile disc herniation. Recently, similarities in degenerative findings of the lumbar spine between identical twins have been reported.

METHODS

In the case group, 24 patients who were the immediate relatives of patients who had undergone surgery for disc herniation and who presented or had a history of low back pain and/or unilateral leg pain were included. Control individuals included 72 age- and gender-matched outpatients who reported low back pain and/or leg pain without a family history of operated disc herniation. The incidence, level, and topographic location of disc herniation/diffuse bulge; the incidence and grade of disc degeneration observed on magnetic resonance images; and degenerative changes suggesting disc degeneration observed on plain radiographs were compared between the relatives of patients with disc herniation (cases) and the controls.

RESULTS

The incidence of disc degeneration at L4-L5 and L5-S1 in cases (L4-L5, 18/24; L5-S1, 18/24) and controls (L4-L5, 45/72; L5-S1, 43/72) was similarly high. However, the grade of disc degeneration according to magnetic resonance imaging signal intensity on the T2-weighted sagittal image using Schneiderman's four-grade classification was significantly more severe in cases (L4-L5: Grade 1, 6/24; Grade 2, 4/24; Grade 3, 13/ 24; Grade 4, 1/24; L5-S1: Grade 1, 6/24; Grade 2: 3/24, Grade 3: 12/24, Grade 4: 3/24) than in controls (L4-L5: Grade 1, 27/72; Grade 2, 24/72; Grade 3, 20/72; Grade 4, 1/72; P = 0.034; L5-S1: Grade 1, 29/72; Grade 2, 23/72; Grade 3, 13/72; Grade 4, 7/72; P = 0.023; Mann-Whitney U test). The incidence of disc herniation/diffuse bulge at L4-L5 (16/24) and L5-S1 (11/24) in cases was higher than that in controls (L4-L5, 33/72; P = 0.07; L5-S1, 17/ 72; P = 0.04; chi-square test).

CONCLUSION

The current study provided evidence that a family history of operated lumbar disc herniation has a significant implication in lumbar degenerative disc disease. There may be a genetic factor in the development of lumbar disc herniation as an expression of disc degeneration.

Periosteal stripping in achondroplastic children. Little effect on limb length in 10 cases

We present a prospective study of the results of periosteal stripping and division in 10 achondroplastic children. A single limb (femur and tibia) was operated on and the change in actual length of each bone and the percentage change in growth compared to that of the non-operated limb was measured by scanogram. The mean absolute increase in growth was small, measuring 3 mm for the femur and 2 mm for the tibia. There was no measurable growth difference after 18 months. This method of increasing limb length in achondroplastic children prior to definitive and extensive lengthening procedures is not recommended.

Spine injuries in gymnasts and swimmers. An epidemiologic investigation

Three groups of top level female gymnasts of preelite, elite, national and Olympic caliber were studied without regard to back pain or injury. These athletes were compared to a similar group of national caliber female swimmers. Magnetic resonance imaging scans of each participant were used to document disk or bony abnormalities. The relationship between magnetic resonance imaging findings and age, height, weight, previous injuries, back symptoms, and hours of training per week each year was examined. Nine percent of preelite (1/11), 43% of elite (6/14), and 63% of Olympic level (5/8) gymnasts had spine abnormalities; 15.8% of all swimmers had spine abnormalities. Average hours of training per week and age were found to be associated with abnormalities seen on magnetic resonance imaging. Increased intensity and length of training correlated with previous data that suggests the female gymnast is prone to spine injuries.

The classification of low back pain

The majority of patients with low back pain offer no objective clinical findings on which to make a diagnosis on the basis of physical examination. Therefore a diagnostic categorization of complaint based on duration and location is proposed. The justification for this organization is the assumption that the majority of back pain is secondary to deterioration within the disc. Thus the appropriate treatment program is focused at methods designed to find the pain source, and look to the health of the disc. It is on this basis that various treatment approaches for the nine classifications are proposed.