Intervertebral disc changes after 1 h of running: a study on athletes.

The lumbar spines of 25 long-distance runners were examined using an upright magnetic resonance imaging scanner. All volunteer runners were scanned before and after running for 1 h. Scanning was performed with the runners seated upright (neutral), leaning forwards (flexion) and leaning backwards (extension). All measured discs showed a reduction in disc height after 1 h of running. A significant reduction in disc height was observed in all three body positions (neutral, flexion and extension) after 1 h of running. The results showed that, in flexion, extension and neutral positions, intervertebral discs undergo significant strain after 1 h of running. The lowest disc-height reduction was found at the L5 - S1 space in the neutral position; the same space had the highest percentage of disc degeneration.

Pre-operative versus post-operative gait variability in patients with acute anterior cruciate ligament deficiency.

Change in gait variability at least 6 months after surgical reconstruction of the anterior cruciate ligament (ACL) was assessed in 20 male patients with acute ACL deficiency and compared with pre-operative data and that from 20 healthy male controls. Gait was measured using a triaxial accelerometer and data were analysed by the Gait Evaluation Differential Entropy Method (GEDEM) to determine gait variability. Pain was assessed with a visual analogue scale and functional ability with the Oswestry Disability Index and the International Knee Documentation Committee score. Mean gait variability was significantly lower after than before surgery, with values for the anterior-posterior axis being in the normal range of controls after 6 months, whereas in the mediolateral axis mean gait variability remained significantly higher, indicating that some rotational instability remained in the time-frame of the study. Pain and functional ability scores improved after surgery compared with before surgery. The combination of accelerometry and GEDEM may be a useful orthopaedic tool for the post-operative evaluation of patients who have undergone ACL reconstruction.

Influence of acute anterior cruciate ligament deficiency in gait variability.

The objective of this study was to compare the gait variability of patients with isolated anterior cruciate ligament (ACL) deficiency (experimental group) with that of healthy individuals (control group). The hypothesis was that the gait variability of the experimental group would be higher than the control group. The experimental group consisted of 20 men with an ACL tear and the control group consisted of 20 healthy men without any neurological and/or musculoskeletal pathology or injury. The gait acceleration signal was analysed using the Gait Evaluation Differential Entropy Method (GEDEM). The GEDEM index of the experimental group in the medio-lateral axis was significantly higher than that of the control subjects. A receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of the method and to determine a cut-off entropy value. The GEDEM cut-off value had a 95.6% probability of separating isolated ACL patients from healthy subjects.

Gait variability measurements in lumbar spinal stenosis patients: part A. Comparison with healthy subjects.

The objective of this study is to compare the gait variability of patients with lumbar spinal stenosis (experimental group) with healthy individuals (control group). The hypothesis is that the preoperative gait variability of the experimental group is higher than the control group. The experimental group consisted of 35 adults (18 males, 17 females). The subjects of the experimental group suffered exclusively from spinal stenosis. The patients were determined by MRI scans. A tri-axial accelerometer sensor was used for the gait measurement, and differential entropy algorithm was used to quantify the gait acceleration signal. The Oswestry Low Back Pain Questionnaire was used to determine the condition on the day of the measurement. Receiver operating characteristic (ROC) was utilized to assess the diagnostic value of the method and determine a cut-off value. There is a statistically significant difference between gait variability in the control group and the experimental group. ROC analysis determines a cut-off differential entropy value. The cut-off value has a 97.6% probability of separating patients with spinal stenosis from healthy subjects. The Oswestry Low Back Questionnaire is well correlated with the spectral differential entropy values.

Gait variability measurements in lumbar spinal stenosis patients: part B. Preoperative versus postoperative gait variability.

The objective of this study was to assess the gait variability of lumbar spinal stenosis (LSS) patients and to evaluate its postoperative progression. The hypothesis was that LSS patients' preoperative gait variability in the frequency domain was higher than the corresponding postoperative. A tri-axial accelerometer sensor was used for the gait measurement and a spectral differential entropy algorithm was used to measure the gait variability. Twelve subjects with LSS were measured before and after surgery. Preoperative measurements were performed 2 days before surgery. Postoperative measurements were performed 6 and 12 months after surgery. Preoperative gait variability was higher than the corresponding postoperative. Also, in most cases, gait variability appeared to decrease throughout the year.

Accelerometry for evaluation of gait pattern in healthy soccer athletes.

An accelerometer system was used to measure the characteristics of the motion of 133 healthy male soccer athletes in a 30-s walking test and the data obtained were analysed using the gait evaluation differential entropy method (GEDEM). GEDEM processes gait acceleration data and calculates an index that provides a quantitative evaluation of a subject's gait, at low cost and with negligible effect on the subject. The GEDEM index was not significantly correlated with age, body weight, body mass index, or the number of years of active training. The GEDEM value for the anterior-posterior axis showed a small negative statistically significant correlation with height and the vertical axis was moderately and statistically significantly positively correlated with the time spent training per week. The triaxial accelerometry system described here is easy for subjects and testers to use, and enables measurements to be made on the sports field to evaluate an athlete's musculoskeletal condition with respect to gait stability.

Paget's disease of the spine and its management.

A review of the literature was conducted to study the pathomechanics by which Paget's Disease of bone (PD) alters the spinal structures that result in distinct spinal pathologic entities such as pagetic spinal arthritis, spinal stenosis, and other pathologies, and to assess the best treatment options and available drugs. The spine is the second most commonly affected site with PD. About one-third of patients with spinal involvement exhibit symptoms of clinical stenosis. In only 12-24% of patients with PD of the spine is back pain attributed solely to PD, while in the majority of patients back pain is either arthritic in nature or a combination of a pagetic process and coexisting arthritis. Neural element dysfunction may be attributed to compressive myelopathy by pagetic bone overgrowth, pagetic intraspinal soft tissue overgrowth, ossification of epidural fat, platybasia, spontaneous bleeding, sarcomatous degeneration and vertebral fracture or subluxation. Neural dysfunction can also result from spinal ischemia, when blood is diverted by the so-called "arterial steal syndrome". Because the effectiveness of pharmacologic treatment for pagetic spinal stenosis has been clearly demonstrated, surgical decompression should only be instituted after failure of antipagetic medical treatment. Surgery is indicated as a primary treatment when neural compression is secondary to pathologic fractures, dislocations, spontaneous epidural hematoma, syringomyelia, platybasia, or sarcomatous transformation. Since, in the majority of cases with pagetic spinal involvement, there are also coexisting osteoarthritic changes, antipagetic medical treatment alone may be disappointing. Therefore, one must be careful before attributing low back pain to PD alone. Five classes of drugs are available for the treatment of PD: bisphosphonates, calcitonins, mithramycin (plicamycin), gallium nitrate, and ipriflavone. Bisphosphonates are the most popular, and several forms have been investigated, but only the following forms have been approved for clinical use: disodium etidronate, clodronate, aledronate, risedronate, neridronate, pamidronate, tiludronate, ibadronate, aminohydroxylbutylidene bisphosphonate, olpadronate, and zoledronate. Several of these forms are still under investigation.

Plaster of Paris as bone substitute in spinal surgery.

In order to assess the effectiveness of calcium sulphate (plaster of Paris; POP) as a substitute for autologous bone graft, we performed lumbar intervertebral fusion in mature sheep using POP and a variety of other graft materials, and reviewed the literature. The osteoconductivity of the POP grafts was compared to that of grafts carried out with autogenous iliac crest, frozen allogeneic bone, and ProOsteon 500 coralline bone. We also compared the osteogenicity of POP to admixtures of autogenous iliac crest bone with POP and coralline bone, and to an osteoinductive demineralized sheep bone preparation (DBM). The substrates were loaded into tubular titanium mesh, implanted into excavated disc spaces and recovered after a period of 4 months. Fusion mass segments tested in flexion and tension showed that POP was equal to autogenous bone and most other substrates. The POP fusions were significantly tougher than the DBM fusions, even though histomorphometry failed to reveal differences in the amount of trabecular bone. We conclude that POP can be used to achieve a biomechanically stable interbody lumbar vertebral fusion. In addition, our literature review indicated that POP can be used as a vehicle for local delivery of antibiotics in bone infections.

Seven- to 20-year outcome of lumbar discectomy.

STUDY DESIGN: A retrospective, follow-up study. OBJECTIVES: To assess the effects of conventional surgery for lumbar disc herniation over an extended period of time and to examine factors that might correlate with unsatisfactory results. SUMMARY OF BACKGROUND DATA: Although the short-term results of lumbar discectomy are excellent when there is a proper patient selection, the reported success rates in the long-term follow-up studies vary, and few factors have been implicated for an unsatisfactory outcome. METHODS: One hundred-nine patients with surgically documented herniated lumbar disc were analyzed, retrospectively, by an independent observer. Long-term follow-up (mean 12.2 years) was done by a mailed, self-report questionnaire that included items about pain relief in the back and leg, satisfaction with the results, need for analgesics, level of activity, working capacity, and reoperations. Subjective disability was measured by the Oswestry questionnaire. Radiographic review was carried out in 66% of patients. End results were assessed using the modified Stauffer-Coventry's evaluating criteria. Several variables were examined to assess their influence to the outcome. RESULTS: The late results were satisfactory in 64% of patients. The mean Oswestry disability score was 18.9. Of the 101 patients who had primary procedures, 28% still complained of significant back or leg pain. Sixty-five percent of patients were very satisfied with their results, 29% satisfied, and 6% dissatisfied. The reoperation rate was 7.3% (8 patients), about one-third of which was due to recurrent disc herniation. Sociodemographic factors predisposing to unsatisfactory outcome, including female gender, low vocational education, and jobs requiring significant physical strenuousness. Disc space narrowing was common at the level of discectomy, but was without prognostic significance. CONCLUSIONS: The long-term results of standard lumbar discectomy are not very satisfying. More than one-third of the patients had unsatisfactory results and more than one quarter complained of significant residual pain. Heavy manual work, particularly agricultural work, and low educational level were negative predictors of a good outcome. These indicators should be used preoperatively to identify patients who are at high risk for an unfavorable long-term result.

Treatment of unstable thoracolumbar and lumbar spine injuries using Cotrel-Dubousset instrumentation.

STUDY DESIGN: In this prospective study, the results of treating unstable thoracolumbar and lumbar injuries with Cotrel-Dubousset instrumentation were investigated. OBJECTIVE: To determine the pain and work status of the patients, to evaluate neurologic status, and to assess the efficacy of instrumentation in the short term. SUMMARY OF BACKGROUND DATA: Short-segment pedicle screw construct is the method of choice for reduction and stabilization of unstable thoracolumbar spinal injuries. Many investigators have recently reported a high rate of instrument failure. In this study, the use of segmental transpedicular fixation two levels above the kyphosis decreased instrument failure and sagittal collapse. METHODS: Thirty patients, who had unstable thoracolumbar and lumbar spinal injuries, underwent application from a posterior approach of Cotrel-Dubousset instrumentation two levels above and one below at the thoracolumbar junction and short segment fixation in the lumbar area. Radiologic parameters were evaluated before and after surgery. RESULTS: The mean follow up was 31 months (range, 25-49) months. There were statistically significant differences between the pre- and postoperative values in all radiologic parameters. Neurologic status improved in 70% of the patients, with a mean Frankel grade of 1.3 grades. CONCLUSIONS: Cotrel-Dubousset instrumentation provided spinal stability in unstable injuries, forming a rigid construct and restoring physiologic thoracolumbar and lumbar postural contours because of its highly corrective effect in the sagittal profile with no loss of correction.

Acute poisonings and sudden deaths in Crete: a five-year review (1991-1996).

Fatal and non-fatal acute poisonings and other sudden deaths examined in the Toxicology Laboratory of University Hospital of Iraklion, Crete, from 1991 to 1996 mainly involved the abuse of drugs (heroin, flunitrazepam and other psychoactive substances), accidental poisonings or suicide attempts with pesticides (carbamates, organophosphates, paraquat), other chemicals (cyanide salts, paint thinner, chlorine), traffic accidents, drownings and violent deaths (gunshots). Many of the cases were related to poisonous gases or volatiles (carbon monoxide, methylbromide). Fatalities due to alcohol and methylene-dioxy-ethyl amphetamine were also examined. Amphetamine and alcohol-related deaths due to drowning were more recent. A significant number of cases were related to the accidental ingestion of alcohol, drugs or suicide attempts by children. Some of the cases were treated successfully in various Cretan hospitals, while others had fatal outcomes due to late hospital admission.

Rolando's fracture treated by closed reduction and external fixation.

In 11 patients with a Rolando's fracture of the first metacarpal, the mini-Hoffman external fixation was used to maintain closed reduction of the fracture, with two pins placed distally in the first metacarpal and one pin proximally in the trapezium. The results were excellent in 7 patients; in 3 patients mild arthritis was noted radiographically, and one patient had a poor result because of severe postraumatic arthritis 1-5 years (mean 30 months) after the injury. This method of treatment is proposed for patients with Rolando's fracture as it is very easily performed and provides good results.

Subcoracoid trapping of the proximal fragment of a fractured clavicle.

An unusual indication--not previously reported--for surgical treatment of a clavicle fracture, in a 56-year-old male, is presented. The proximal fragment had been entrapped under the coracoid, and there were symptoms from impairment of the musculocutaneous nerve. Reduction by closed means proved unsuccessful, and an open procedure was necessary for this rare type of the common clavicle fracture.

Placement of the distal locking screws of the femoral intramedullary nail without radiation.

An H-shaped device was invented to facilitate placement of the distal interlocking screws during closed femoral nailing. Eleven sound cadaveric femurs were experimentally nailed before the application of the device in 15 patients with a femoral shaft fracture. In all experimental cases the insertion of the distal screws proved to be easy. In 11 of 15 patients with a femoral fracture, distal locking was achieved using the H-device. These primary results should stimulate further clinical application of the device.

The innervation of the human meniscus.

Fourteen menisci from seven anatomic specimens were examined to identify their innervation. After staining by a modified gold chloride method, the menisci were sectioned on a sliding microtome and were studied under a light microscope. Free nerve endings in the peripheral and the medial thirds of the meniscal body were identified, and three types of encapsulated mechanoreceptors were found in the anterior and posterior horns. Based on these findings and a review of the relevant literature, it is considered that menisci both receive and transmit proprioceptive information. Therefore, they not only are stabilizers of this joint, but also contribute to the function of deep sensitivity.

Mechanoreceptors in the posterior cruciate ligament. Histologic study on cadaver knees.

The purpose of the study was to identify mechano-receptors in the healthy, human posterior cruciate ligament. Ten ligaments from 10 fresh cadavers were studied with light microscopy. In addition to free nerve endings, two types of encapsulated mechanoreceptors were identified. They were located at the femoral and tibial attachments, and on the surface of the ligament. These findings support the hypothesis that the posterior cruciate ligament has an anatomic basis for a discriminating afferent flow of nerve impulses to the central nervous system. Therefore, its neural network may play a role in regulating the contraction of muscle groups that are fundamental to knee stability.