Radiographic anatomic structure of the arthritic acetabulum and its influence on total hip arthroplasty.

Acetabular bone structure is not the same in all patients and can be defined by the radiolucent triangle superior to the acetabulum. Of 132 hips, 81 had an isosceles triangular shape, which was named type A acetabulum. Forty-six hips had an extension of the triangle into the teardrop, which created a thickened medial wall and was named type B. Five hips had a right-angle triangle, which was found only with congenital disease of the hip and was named type C. The density of the superior acetabular bone in the triangle could be normally radiolucent (stage I), have vertical and transverse trabeculae throughout the triangle (stage II), or have the triangle filled with bone and cysts (stage III). The relationship between progressive radiolucent lines and acetabular type showed that type A3 (thin medial wall with dense triangle bone) had the highest incidence of progressive radiolucent lines (P < .05).

Acute traumatic myelopathy secondary to a thoracic cyst in a professional football player.

STUDY DESIGN: Case report of acute traumatic myelopathy secondary to thoracic synovial cyst in a professional football player. OBJECTIVE: To emphasize examination for myelopathy and describe the radiographic and magnetic resonance findings of a rare source of traumatic myelopathy. BACKGROUND: Magnetic resonance imaging is the best initial evaluation for myelopathy in a traumatic setting. Heightened awareness during evaluation of a player involved in a traumatic incident allowed the diagnosis of potential cord damage and paralysis. METHODS: A subject with symptoms resulting from a direct blow to the back was evaluated for myelopathy, with diagnosis assisted by magnetic resonance imaging used to pinpoint the source of the disorder. RESULTS: The diagnosis allowed a surgical excision of the traumatic synovial cyst and full recovery of the injured football player. CONCLUSIONS: Awareness during examination for myelopathy in an acutely injured athlete is imperative to prompt the clinician to order the proper diagnostic studies and thereby embark on a surgical correction of the problem.

Lumbar lordosis. Effects of sitting and standing.

STUDY DESIGN: The effect of sitting versus standing posture on lumbar lordosis was studied retrospectively by radiographic analysis of 109 patients with low back pain. OBJECTIVE: To document changes in segmental and total lumbar lordosis between sitting and standing radiographs. SUMMARY OF BACKGROUND DATA: Preservation of physiologic lumbar lordosis is an important consideration when performing fusion of the lumbar spine. The appropriate degree of lumbar lordosis has not been defined. METHODS: Total and segmental lumbar lordosis from L1 to S1 was assessed by an independent observer using the Cobb angle measurements of the lateral radiographs of the lumbar spine obtained with the patient in the sitting and standing positions. RESULTS: Lumbar lordosis averaged 49 degrees standing and 34 degrees sitting from L1 to S1, 47 degrees standing and 33 degrees sitting from L2 to S1, 31 degrees standing and 22 degrees sitting from L4 to S1, and 18 degrees standing and 15 degrees sitting from L5 to S1. CONCLUSION: Lumbar lordosis while standing was nearly 50% greater on average than sitting lumbar lordosis. The clinical significance of this data may pertain to: 1) the known correlation of increased intradiscal pressure with sitting, which may be caused by this decrease in lordosis; 2) the benefit of a sitting lumbar support that increases lordosis; and 3) the consideration of an appropriate degree of lordosis in fusion of the lumbar spine.

Dynamic electromyographic analysis of trunk musculature in professional golfers.

Using dynamic surface electrode electromyography, we evaluated muscle activity in 13 male professional golfers during the golf swing. Surface electrodes were used to record the level of muscle activity in the right abdominal oblique, left abdominal oblique, right gluteus maximus, left gluteus maximus, right erector spinae, left erector spinae, upper rectus abdominis, and lower rectus abdominis muscles during the golfer's swing. These signals were synchronized electronically with photographic images of the various phases of the golf swing; the images were recorded in slow motion through motion picture photography. The golf swing was divided into five phases: take away, forward swing, acceleration, early follow-through, and late follow-through. Despite individual differences among the subjects' swings, we observed reproducible patterns of trunk muscle activity throughout all phases of the golf swing. Our findings demonstrate the importance of the trunk muscles in stabilizing and controlling the loading response for maximal power and accuracy in the golfer's swing. This study provides a basis for developing a rehabilitation program for golfers that stresses strengthening of the trunk muscles and coordination exercises.

Lumbar lordosis in spinal fusion. A comparison of intraoperative results of patient positioning on two different operative table frame types.

STUDY DESIGN: One hundred one patients undergoing spine surgery for degenerative conditions were entered into a prospective radiographic evaluation of changes in lumbar lordosis as affected by positioning on two different operative tables. OBJECTIVES: The hypothesis of the present study is twofold: 1) the positioning of patients on specific types of operative tables may affect significantly the overall degree of lumbar lordosis obtainable, and 2) certain operative positioning may more accurately reproduce physiologic standing lateral lumbar lordosis. SUMMARY OF BACKGROUND DATA: In the management of degenerative and post-traumatic spinal deformities, lumbar fusion using posterior instrumentation permits more accurate and physiologic lordotic positioning of the involved fusion segments of the lumbar spine. However, various types of operating frames are available for use in this type of surgery, and despite the overall importance of correct lordotic positioning, there is some question as to what effect on positioning, as measured in degrees of lumbar lordosis, a particular frame might have. METHODS: Total, multisegmental, and unisegmental Cobb angle measurements of preoperative standing lateral radiographs and intraoperative lateral radiographs after positioning on respective operative tables were determined. Fifty-one patients were positioned on an Andrews-type table, and 50 patients were positioned on the four-poster-type frame. Statistical comparison using analysis of variance testing of changes in lordosis before and after surgery between study groups was evaluated. RESULTS: Lumbar lordosis measured from L1 to S1 with standing lateral radiographs showed a combined mean preoperative measurement of 45.18 degrees, with no statistical significance between groups. In comparison, there was a statistically significant difference between intraoperative measurements from L1 to S1 on the Andrews table versus the four-poster frame, revealing an average of 32.81 degrees versus 47.71 degrees, respectively (P < 0.005). Multisegmental lordosis measurement from L2 to S1 displayed statistical significance between groups, with a combined preoperative standing lateral radiograph average of 43.32 degrees, and intraoperative values of 31.28 degrees on the Andrews table versus 45.34 degrees on the four-poster frame (P < 0.005). Multisegmental lordosis measurements from L4 to S1 displayed statistical significance between groups, with a combined preoperative standing lateral radiograph average of 31.40 degrees and intraoperative values of 23.14 degrees on the Andrews table versus 32.94 degrees on the four-poster frame (P < 0.005). Segmental lordosis at L5-S1 was less dependent on frame type, with a combined preoperative standing lateral radiograph average of 20.53 degrees and intraoperative measurements of 20.06 degrees on the Andrews table versus 21.02 degrees on the four-poster frame (P < 0.43). CONCLUSION: Results from the present study display a statistically significant difference between multisegmental and total lumbar lordosis, depending on the type of operative table used in patient positioning. Segmental lordosis at L5-S1 depended less on frame type. This table-dependent positional change in lumbar lordosis could be incorporated easily into a lumbar fusion procedure, especially when supplemented with instrumentation, affecting the permanent overall degree of lordosis. These results suggest that a more physiologic degree of lumbar lordosis is obtained accurately with use of an operative table similar to the four-poster frame.

The older athlete after lumbar spine surgery.

Surgery consists of spinal decompression for predominately leg pain problems. The most commonly performed surgery in older patients is the lumbar laminectomy. Total laminectomy is the procedure recommended for central canal stenosis. More commonly, central canal, lateral recess, and foraminal stenosis occur in the same patient. Lateral recess stenosis may be the major offending blockage in the canal. This may be treated with a total laminectomy or a bilateral medial facetectomy performed through the microscope with excellent decompression of the lateral recess. Foraminal stenosis can also be decompressed from a paraspinous position with the foraminotomy performed from the outside in. This can be combined with a microscopic medial facetectomy. Essentially, all these operations remove bone and redundant tissue to allow the nerve adequate freedom in the spinal canal and/or intervertebral foramina. Fusions are performed predominantly for degenerative spondylolisthesis to prevent the recurrence of radiculopathy. Internal fixation may be indicated in any situation in which the surgeon feels that the fusion rate is potentially compromised, but he or she must be aware that internal fixation does not guarantee spine fusion. Spinal instrumentation certainly increases the complication rate. The number of levels fused and the inclusion of the sacrum are important in predicting the fusion rate.

Incidence of cervical spinal stenosis in professional and rookie football players.

Sagittal canal/vertebral body ratios were measured on cervical spine lateral radiographs of 124 professional football players and 100 rookie football players. A total of 894 levels were measured in 224 players. Thirty-two percent (40) of the 124 professional football players, and 34% of the 100 rookies had a ratio of less than 0.80 at one or more levels from C3 to C6. The 0.80 ratio has been considered indicative of cervical spinal stenosis. This is the first time that the incidence of spinal stenosis, as determined by Torg's ratio, has been demonstrated in a population of professional and rookie football players. Because one-third of this population has cervical spinal stenosis as determined by the Torg ratio, other factors should be considered in the evaluation of a player with a transient quadriplegic episode when making continued play decisions.

Lumbar spine injury in the athlete.

In summary, the keys to proper management of lumbar spine problems in athletes include (1) comprehensive diagnosis; (2) aggressive, effective nonoperative care; and (3) pinpointing operations that do as little damage as possible to normal tissue but correct the pathologic lesion.

The role of spinal flexion and extension in changing nerve root compression in disc herniations.

Changes in nerve root compression forces with spinal motion were measured on six freshly frozen adult cadaver spine specimens. A model was devised to represent a herniated disc at the L4-5 level. This was done using an anterior approach placing a compression-measuring device through the disc at the L4-5 level and against the L5 root. An accelerometer was used to monitor the range of motion of the spine. Because the compression device was held in a static position, the only variable was the tautness of the nerve root across the tip of the device. By simultaneously monitoring motion and force delivered at the tip of the compression meter placed at the nerve root, we were able to quantitate nerve root tension forces across the tip of the measuring device in relation to spinal motion. The force was measured with controls as well as in flexion and extension. In addition, the force was measured as traction was applied to the L5 root. The amount of compressive force and tension in the nerve root increased with flexion of the spine and decreased with extension of the spine. In conclusion, flexion of the lumbar spine increased the compressive force on the L5 root and extension decreased the compressive force on the L5 root.

Dynamic EMG analysis of torque transfer in professional baseball pitchers.

Fifteen professional baseball pitchers underwent active pitching motion analysis of the abdominal oblique, rectus abdominis, lumbar paraspinous and gluteus maximus muscles bilaterally via surface electrode evaluation. Baseline resting and isometric maximum values were obtained and active data referenced against these for comparison. The muscle activity then was measured during the pitching sequence and analyzed in each of the five pitching phases. The abdominal oblique, lumbar paraspinous and rectus abdominis contralateral to the pitching arm and the ipsilateral gluteus maximus all had increases in activity level of 75 to 100% during the active pitching motion. Using these data indicating specific muscle group patterns with clinical and performance data, we hope to minimize injuries and maximize pitching performance.

Magnetic resonance imaging in the diagnosis of disc degeneration: correlation with discography.

One hundred and one disc levels in 36 patients with low-back pain were studied with magnetic resonance imaging (MRI) (T2-weighted) sagittal images and conventional roentgenographic discography to detect early disc degeneration. Thirty-nine discs also were evaluated after discography with roentgenographic CT MRI findings were compared with discography results. MRI was 99% accurate in predicting normality or abnormality as determined by discography. Changes in disc signal on MRI accurately reflected the presence or absence of degenerative changes seen on discography in patients with low-back pain. Clinically, MRI is a useful technique for detecting early disc degeneration and for assessing the affected disc level and adjacent levels in patients with low-back pain and spondylolithesis.

Comparisons of preoperative and postoperative MMPI data in chronic back patients.

The purpose of this study was to analyze 42 patients disabled with low-back pain in order to assess Minnesota Multiphasic Personality Index (MMPI) changes before and after surgery, the predictive value of MMPI, the results of anterior lumbar fusion in one group of severely disabled lumbar low-back pain patients. Statistical analyses were performed to compare and contrast MMPI, pain assessment, functional and occupational levels, and disability index before and after surgery. The degree of morbidity of the patients preoperatively was severe. After surgery, the majority of the patients showed improvement in their overall status. The available evidence suggests the following: Improvement in physical condition can produce improvement in psychological test scores; The preoperative MMPI is not a reliable indicator of surgical success.

Neck injuries in football players.

Understanding neck injuries in football players starts with understanding how the game is played--not the strategy, but the training techniques and requirements of the game. Neck injuries are an unavoidable part of the game. What can be improved are the preventative measures, the treatment techniques, and some standardization of risk factors in playing after a neck injury. Prevention starts with decreasing the use of the head as an offensive weapon and with proper shoulder pads. Treatment begins with proper on-field evaluation and transportation techniques and is completed by good consultation services. Proper evaluation of risk demands open discussions with the patient of all factors involved. Clear advice is given to players and to the team through their medical staff.