Radiostereometric analysis for monitoring percutaneous physiodesis. A preliminary study.

Percutaneous physiodesis is an established technique for treating mild leg-length discrepancy and problems of expected extreme height. Angular deformities resulting from incomplete physeal arrest have been reported, and little is known about the time interval from percutaneous physiodesis to actual physeal arrest. This procedure was carried out in ten children, six with leg-length discrepancy and four with expected extreme height. Radiostereometric analysis was used to determine the three-dimensional dynamics of growth retardation. Errors of measurement of translation were less than 0.05 mm and of rotation less than 0.06 degrees. Physeal arrest was obtained in all but one child within 12 weeks after physiodesis and no clinically-relevant angular deformities occurred. This is a suitable method for following up patients after percutaneous physiodesis. Incomplete physeal arrest can be detected at an early stage and the procedure repeated before corrective osteotomy is required.

Results of hip revision using the Exeter stem, impacted allograft bone, and cement.

The Exeter stem and impacted, morselized allograft bone and cement were used in the revisions of 18 consecutive femoral components (17 patients). The primary arthroplasty had been done because of osteoarthritis. All of the femoral components were revised for the first time because of aseptic loosening. The migration pattern of the Exeter stem after revision was studied using roentgen stereophotogrammetric analysis. At 2 years after surgery, all 18 femoral stems had migrated in the distal direction (average, 2.5 mm). In addition, seven of the stems had migrated in the medial direction (average, 1.3 mm), and two stems had migrated in the lateral direction (0.5 mm and 1 mm, respectively). Sixteen of the femoral stems also had migrated in the posterior direction (average, 2.9 mm), but none migrated in the anterior direction. The migration rate decreased gradually with time during the followup. Six femoral stems continued to migrate between 1.5 and 2 years after surgery. In patients with major femoral bone deficiency at the time of hip revision, the use of impacted morselized allograft bone and cement yielded an initial fixation similar to that obtained in conventionally cemented revisions. Pain had improved in all patients at the 2-year followup.

Radiostereometric analysis in hip revision surgery--optimal time for index examination: 6 patients revised with impacted allografts and cement followed weekly for 6 weeks.

We revised the hip (6 stems and 5 sockets) with impacted morselized allografts and cement in 6 patients. We followed prosthetic migration by roentgen radiostereometric analysis (RSA) every 7th day for 6 weeks after the first (index) examination performed on the first postoperative day before mobilization. Most of the migration occurred during the first 2 weeks. In most cases more than half of the distal stem migration was seen between the 1st and 14th days. In all cases, the stem and socket migrations slowed down gradually and several prosthetic components had become stable after 5 weeks. We conclude that it is essential to perform the index RSA examination on the 1st or 2nd day after surgery and to state when and how weight bearing should be permitted. Otherwise it will be difficult to compare prosthetic migration in various studies and define normative values for migration predicting survival.

A method to evaluate the in vivo behaviour of lumbar spine implants.

The aim of the study was to design a method for evaluating the stabilizing effect of different lumbar spine implants in vivo, and to apply this method to a comparison of plates versus rods in lumbar spine posterolateral fusion using transpedicular screw fixation. Fourteen patients, seven operated on with transpedicular plates and screws (VSP), and seven operated on with rods and screws (Diapason), matched according to number of levels fused, had tantalum markers inserted in the vertebrae at surgery, enabling roentgen stereophotogrammetric analysis (RSA). Mean patient age was 45 (range 33-56) years. In each group, two patients underwent fusion between L4 and L5, three between L5 and S1, and two from L4 to S1. In three patients, concomitant nerve root decompression was performed using a facet joint preserving technique. RSA was performed 4 weeks after surgery. This interval was chosen to allow enough time for soft tissue healing, but not fusion healing, to occur. RSA was performed in supine and standing position without any mobility provocation, in line with the postoperative regimen given. Movements between the outermost vertebrae of the fusion were calculated along the transverse, vertical and sagittal axes. The method of measurement along these three axes has previously been determined to be accurate to 0.3, 0.6 and 0.7 mm, respectively. One patient stabilized with rods and screws between L5 and S1 displayed a sagittal translation of 1.01 mm but no mobility along the transverse or vertical axes. In the remaining 13 patients, positional change from supine to standing did not provoke any intervertebral mobility above the RSA accuracy along any of the axes. With the limited provocation described, in line with the postoperative regimen for lumbar fusion patients, plates with transpedicular screws and rods with transpedicular screws both seem to give adequate intervertebral stability in posterolateral lumbar fusions.

Is there increased intervertebral mobility in isthmic adult spondylolisthesis? A matched comparative study using roentgen stereophotogrammetry.

STUDY DESIGN: By roentgen stereophotogrammetric technique, the intervertebral mobility of the spondylolytic segment in eight patients was measured and compared with the mobility of eight nonspondylolytic patients matched according to sex, afflicted segment, and grade of disc degeneration. OBJECTIVES: To compare the intervertebral mobility of a spondylolytic segment with the mobility of a segment without spondylolysis in adult patients with back pain. SUMMARY OF BACKGROUND DATA: Evidenced by the resulting olisthetic deformity and supported by the outcome from prior investigations, spondylolysis is assumed to induce spinal segmental instability/hypermobility. METHODS: After percutaneous application of tantalum indicators for roentgen stereophotogrammetric technique, the intervertebral translations of the spondylolytic fifth lumbar vertebra were measured in eight adult patients with low back pain and low-grade olisthesis. Eight other patients without spondylolysis but with low back pain presumably on degenerative basis were chosen for comparison and had an identical measuring procedure using roentgen stereophotogrammetric technique. The two groups were matched in pairs according to sex, afflicted segment, and grade of disc degeneration. RESULTS: No significant difference was registered considering the intervertebral mobility for matched pairs in the two groups neither along the sagittal nor the vertical axis. The transverse translations were mostly negligible in both groups. CONCLUSION: The spondylolytic defect in pars interarticularis does not cause permanent instability/hypermobility detectable in the adult patient with low back pain and low-grade olisthesis.

[Prevalence for clinically proved carpal tunnel syndrome is 4 percent]. / Prevalensen för kliniskt säkerställt karpaltunnelsyndrom 4 procent.

This article summarizes the results of a large-scale population-based study conducted to determine the prevalence of carpal tunnel syndrome in the Swedish general population. The study utilized a health questionnaires as well as clinical and electrophysiological examinations. Population prevalence rates of carpal tunnel syndrome, based on clinical diagnosis and electrophysiological criteria, were calculated. Obesity and specific work-related hand activities were shown to be risk factors for carpal tunnel syndrome.

Median nerve latency measurement agreement between portable and conventional methods.

A portable nerve conduction testing device was compared with a conventional method of measuring median nerve distal latencies. In a population-based study, a health questionnaire was mailed to a random sample of 3000 participants (aged 25 to 74 years). Two hundred and sixty-two responders with numbness and/or tingling in the median nerve distribution, and 125 asymptomatic responders underwent clinical examination as well as portable and conventional median nerve distal latency measurements. Motor latency measured with the portable device was on average 0.1 millisecond (ms) lower than motor latency measured with the conventional method (95% limits of agreement, -0.8-0.5 ms). Sensory latency (wrist-to-index finger) measured with the portable device was on average 0.3 ms lower than sensory latency (long finger-to-wrist) measured with the conventional method (95% limits of agreement, -0.7-0.1 ms). Strong correlations were found between the latencies measured by the portable and conventional methods (Pearson correlation coefficient, 0.90-0.93). The agreement between the portable and conventional methods in measuring median nerve distal latencies appears to be acceptable. The cut-off value for abnormal sensory latency needs to be lower for the portable than the conventional method if the present measurement techniques are used.

Carpal tunnel syndrome with severe sensory deficit: endoscopic release in 18 cases.

Carpal tunnel syndrome (CTS) with severe sensory deficit was treated with endoscopic carpal tunnel release in 18 hands of 16 consecutive patients (median age 72 (28-92) years). In all hands, preoperative 2-point discrimination (2-PD) exceeded 15 mm in the radial and ulnar sides of the pulps of at least 2 of the 3 radial digits. All patients underwent an independent evaluation and answered a questionnaire concerning 11 activities of daily living (ADL) preoperatively and 6 months postoperatively. Complete resolution or improvement in daytime numbness and tingling was reported in 12 of 17 hands, of night symptoms in 12 of 16 hands, and of pain in 10 of 11 hands. The median ADL score improved from 3.1 to 1.4 (on a 1- to 5-point scale). 13 of the 16 patients were satisfied with the outcome. Two-PD had normalized in 14 hands and improved in 2. The results indicate that endoscopic carpal tunnel release is effective in improving symptoms and function in patients with CTS and severe sensory deficit, and that the prognosis for sensory recovery is good.

Migration of the acetabular component after revision with impacted morselized allografts: a radiostereometric 2-year follow-up analysis of 21 cases.

In a consecutive series of hip revisions due to mechanical loosening, using impacted morselized allografts and cement, we followed 21 acetabular components by radiostereometric analysis (RSA) during 2 years. All but 1 acetabular component migrated in the proximal direction (median 2.1 (0.5-6.4) mm). 6 components migrated in the medial direction (median 0.8 (0.4-1.2) mm) and 6 in the lateral (median 0.8 (0.4-2.0) mm). 14 components migrated in the posterior direction (median 0.8 (0.3-2.3) mm) and 1 in the anterior 0.6 mm. The migration rate gradually decreased in all directions, but 7 acetabular components still migrated in at least 1 direction (median 0.3-0.6 mm) between 1.5 and 2 years postoperatively.

Patient satisfaction, function and return to work after knee arthroplasty.

We investigated the working status during 2 years before and 2 years after primary knee prosthetic operation for arthrosis in order to identify preoperative factors predicting patient satisfaction, function and working capacity. 162 patients (86 women) younger than 60 years of age when operated on with a knee prosthesis during 1993 were studied. 91% of the patients returned a Nottingham Health Profile (NHP) questionnaire, and the Social Insurance Office could supply data on all patients. There was a positive association between the duration of pre- and postoperative sick-leave in the patients who returned to work. Preoperative sick-leave longer than 180 days increased the risk of postoperative disability pension, which was not found to be influenced by the grade of the work. Among the 52 patients who returned to work postoperatively, all 6 NHP functional categories were better in the patients with less than 180 days of preoperative sick-leave than in the patients with more than 180 days of preoperative sick-leave. The overall patient satisfaction was greater among patients who went back to work postoperatively. We conclude that long sick-leave before a knee prosthetic operation increases the risk of long postoperative sick-leave and disability pension and impairs the quality of life.

Prevalence of carpal tunnel syndrome in a general population.

CONTEXT: Carpal tunnel syndrome (CTS) is a cause of pain, numbness, and tingling in the hands and is an important cause of work disability. Although high prevalence rates of CTS in certain occupations have been reported, little is known about its prevalence in the general population. OBJECTIVE: To estimate the prevalence of CTS in a general population. DESIGN: General health mail survey sent in February 1997, inquiring about symptoms of pain, numbness, and tingling in any part of the body, followed 2 months later by clinical examination and nerve conduction testing of responders reporting symptoms in the median nerve distribution in the hands, as well as of a sample of those not reporting these symptoms (controls). SETTING: A region in southern Sweden with a population of 170000. PARTICIPANTS: A sex- and age-stratified sample of 3000 subjects (age range, 25-74 years) was randomly selected from the general population register and sent the survey, with a response rate of 83% (n = 2466; 46% men). Of the symptomatic responders, 81% underwent clinical examination. MAIN OUTCOME MEASURES: Population prevalence rates, calculated as the number of symptomatic responders diagnosed on examination as having clinically certain CTS and/or electrophysiological median neuropathy divided by the total number of responders. RESULTS: Of the 2466 responders, 354 reported pain, numbness, and/or tingling in the median nerve distribution in the hands (prevalence, 14.4%; 95% confidence interval [CI], 13.0%-15.8%). On clinical examination, 94 symptomatic subjects were diagnosed as having clinically certain CTS (prevalence, 3.8%; 95% CI, 3.1%-4.6%). Nerve conduction testing showed median neuropathy at the carpal tunnel in 120 symptomatic subjects (prevalence, 4.9%; 95% CI, 4.1%-5.8%). Sixty-six symptomatic subjects had clinically and electrophysiologically confirmed CTS (prevalence, 2.7%; 95% CI, 2.1%-3.4%). Of 125 control subjects clinically examined, electrophysiological median neuropathy was found in 23 (18.4%; 95% CI, 12.0%-26.3%). CONCLUSION: Symptoms of pain, numbness, and tingling in the hands are common in the general population. Based on our data, 1 in 5 symptomatic subjects would be expected to have CTS based on clinical examination and electrophysiologic testing.

External pedicular fixation of the lumbar spine: outcome evaluation by functional tests.

We analyzed the pain-relieving effect and the functional outcome during external pedicular fixation of the lumbar spine. Twenty patients were included, and the diagnoses were disc degeneration with or without facet joint arthrosis in eight patients, pain after decompression in six patients, spondylolysis/olisthesis in two patients, other types of lumbar anomalies in three patients, and pseudarthrosis after prior uninstrumented fusion in one patient. Before application of the external frame, the pain level on the Visual Analogue Scale was registered at rest, as a mean level for the preceding week, and at seven different functional tests. Maximum walking capacity and walking time needed for a standardized distance were also measured. The same test procedure was repeated 1 week postoperatively with the external frame applied in locked position. With stabilization, 11 patients reported pain relief at rest and 14 when approximating the mean pain level for the week. Both these measured levels correlated to the pain level at all of the seven functional tests. Thus, the patients selected for a subsequent fusion based on pain relief during extended functional provocation would not differ from the patients selected by using only the pain-relieving effect at rest. The patients reporting pain relief tended to increase their walking distance (p = 0.06, t test) but not the speed of walking.

The influence of parental age on the risk of Wilms' tumour.

The Brazilian Wilms' Tumour Study Group carried out a hospital-based multicentre case-control study of potential risk factors for the disease between April 1987 and January 1989. The parents of 109 cases of Wilms' tumour (WT) were interviewed when they were admitted to hospital for diagnosis and treatment. Also interviewed were the parents of two controls per case, matched for age, sex and interviewer, who were admitted to the same or nearby hospitals for treatment of non-neoplastic conditions. Odds ratios adjusted for family income and parental education were calculated by conditional logistic regression. Among cases diagnosed before 25 months of age there was a marked gradient of increasing risk of WT with increasing maternal age at the time of the child's birth. There was no increased risk for cases diagnosed after 25 months of age. The effects of paternal age were less marked. Possible explanations for these results are discussed.

Stability of lumbar fusion with transpedicular fixation determined by roentgen stereophotogrammetric analysis.

STUDY DESIGN: An evaluation of the intervertebral stability of transpedicular instrumentation in posterolateral lumbar fusions by roentgen stereophotogrammetric analysis. OBJECTIVES: To determine the in vivo intervertebral stability of posterolateral lumbar fusions augmented with transpedicular screws and plates. SUMMARY OF BACKGROUND DATA: Transpedicular bone screw systems have been found to be as safe and clinically effective as other types of devices in stabilizing surgery of the spine. Many experimental studies have yielded basic data on the stabilizing implant effect in vitro, but the exact in vivo stabilizing effect on human lumbar vertebrae has not been presented previously. METHODS: In 12 patients, the intervertebral stability of posterolateral fusion in the lower lumbar spine augmented with transpedicular screws and plates was evaluated by serial roentgen stereophotogrammetric analysis with the patients in supine and erect positions 1 year after surgery. RESULTS: Screws in each fused vertebra yielded stable fixation or permitted sagittal intervertebral translations smaller than 1 mm induced by the positional change. A widely decompressed and destabilized vertebra without screw fixation yielded persisting intervertebral translations. CONCLUSIONS: The current study demonstrated the adequacy of in vivo stability of lumbar fusions augmented with transpedicular screws and plates. Sagittal translation seems easier to elicit than movements along the other three-dimensional axes. A widely decompressed and destabilized vertebra without screw fixation increases the risk for persisting intervertebral translations. The roentgen stereophotogrammetric analysis technique described seems to be a good way of comparing the in vivo behavior of different implant systems.

Symptoms, disability, and quality of life in patients with carpal tunnel syndrome.

We used validated outcome instruments to measure symptoms, disability, and health-related quality of life in 58 patients with carpal tunnel syndrome (CTS). The patients completed the CTS instrument before and 6 weeks, 3 months, and 6 months after surgery and the Short Form-36 (SF-36) before and 3 months after surgery. The size of clinical change detected by each outcome measure was estimated by the standardized response mean (mean change/ standard deviation of the change). Large improvement was observed for the CTS symptom scale (mean standardized response, 1.4-1.9) and function scale (0.8-1.1). Improvement in SF-36 scales was large for pain (1.0) and moderate for physical role, mental health, and the physical component summary (0.5-0.6). Compared with the general population SF-36 norms (n = 2,181), CTS patients had significantly worse scores for physical functioning, physical role, pain, vitality, and the physical component summary before surgery. After surgery, SF-36 scores had normalized except for physical role and the physical component summary.

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.

The influence of parental age on the risk of Wilms tumour

The Brazilian Wilms' Tumour Study Group carried out a hospital-based multicentre case-control study of potential risk factors for the disease between April 1987 and January 1989. The parents of 109 cases of Wilms' tumour (WT) were interviewed when they were admitted to hospital for diagnosis and treatment. Also interviewed were the parents of two controls per case, matched for age, sex and interviewer, who were admitted to the same or nearby hospitals for treatment of non-neoplastic conditions. Odds ratios adjusted for family income and parental education were calculated by conditional logistic regression. Among cases diagnosed before 25 months of age there was a marked gradient of increasing risk of WT with increasing maternal age at the time of the child's birth. There was no increased risk for cases diagnosed after 25 months of age. The effects of paternal age were less marked. Possible explanations for these results are discussed.

Assessment of sagittal plane segmental motion in the lumbar spine. A comparison between distortion-compensated and stereophotogrammetric roentgen analysis.

STUDY DESIGN: Sagittal plane translatory and rotatory motion was measured in 15 lumbar motion segments of 8 patients by distortion-compensated and stereophotogrammetric Roentgen analysis. OBJECTIVE: To compare measurement precision of the new distortion-compensated Roentgen analysis protocol with that of the established Roentgen stereophotogrammetric technique under realistic clinical conditions. SUMMARY OF BACKGROUND DATA: Roentgen stereophotogrammetric analysis constitutes the most precise method available to assess segmental motion. Because of the invasive nature of the procedure, however, there is interest in alternative, noninvasive protocols suitable for studying larger patient cohorts. METHODS: In 8 patients, segmental motion of 15 lumbar segments that had undergone previous spinal surgery was assessed from stereo views by using Roentgen stereophotogrammetric analysis. Sagittal plane segmental motion was assessed by distortion-compensated Roentgen analysis. Sagittal plane translatory and rotatory motion data obtained by both methods were compared. RESULTS: With respect to Roentgen stereophotogrammetric analysis, sagittal plane rotation was determined by distortion-compensated Roentgen analysis with an error (standard deviation) of 1.4 degrees and a mean difference of less than 0.05 degree. Sagittal plane translation was determined by distortion-compensated Roentgen analysis, with an error of 1.25 mm and a mean difference 0.5 mm. CONCLUSION: Measurement precision of distortion-compensated Roentgen analysis is slightly inferior to that of Roentgen stereophotogrammetric analysis but substantially higher than that of conventional protocols assessing lumbar segmental motion. If measurement precision is considered adequate and if a noninvasive technique is indicated, distortion-compensated Roentgen analysis can be used to provide reliable motion data required for epidemiologic and clinical studies.

Manipulation does not alter the position of the sacroiliac joint. A roentgen stereophotogrammetric analysis.

STUDY DESIGN: A roentgen stereophotogrammetric analysis study of patients with sacroiliac joint dysfunction. OBJECTIVES: To investigate whether manipulation can influence the position between the ilium and the sacrum, and whether positional tests for the sacroiliac joint are valid. SUMMARY OF BACKGROUND DATA: Sacroiliac joint dysfunction is a subject of controversy. The validity of different sacroiliac joint tests is unknown. Long-standing therapeutic tradition is to manipulate supposed dysfunctions of the sacroiliac joint. Many manual therapists claim that their good clinical results are a consequence of a reduction of subluxation. METHODS: Ten patients with symptoms and sacroiliac joint tests results indicating unilateral sacroiliac joint dysfunction were recruited. Twelve sacroiliac joint tests were chosen. The results of most of these tests were required to be positive before manipulation and normalized after manipulation. Roentgen stereophotogrammetric analysis was performed with the patient in the standing position, before and after treatment. RESULTS: In none of the 10 patients did manipulation alter the position of the sacrum in relation to the ilium, defined by roentgen stereophotogrammetric analysis. Positional test results changed from positive before manipulation to normal after. CONCLUSIONS: Manipulation of the sacroiliac joint normalized different types of clinical test results but was not accompanied by altered position of the sacroiliac joint, according to roentgen stereophotogrammetric analysis. Therefore, the positional test results were not valid. However, the current results neither disprove nor prove possible beneficial clinical effects achieved by manipulation of the sacroiliac joint. Because the supposed positive effects are not a result of a reduction of subluxation, further studies of the effects of manipulation should focus on the soft tissue response.

Patient satisfaction and return to work after endoscopic carpal tunnel surgery.

One hundred twenty-eight patients with idiopathic carpal tunnel syndrome were evaluated before surgery and 3 and 6 months after unilateral endoscopic carpal tunnel release. The variables analyzed included patient demographics, symptoms and signs, activities of daily living (ADL), sensibility and strength measurements, preoperative distal motor latency of the median nerve, operating surgeon, postoperative palmar pain and tenderness, return to work, and patient satisfaction with the results of surgery. Multivariate statistical analyses were performed, with patient satisfaction at 6 months after surgery and the time until return to work after surgery as the dependent variables. On stepwise logistic regression analysis of all preoperative variables, significant predictors of patient dissatisfaction at 6 months after surgery were higher age, heavy vibration exposure, worse ADL score, and better distal motor latency. Analysis of all preoperative and 3-month postoperative variables showed heavy vibration exposure, better distal motor latency, and worse 3-month postoperative ADL score to have the strongest independent correlation with patient dissatisfaction at 6 months. No significant independent association was found between any of the preoperative variables studied and the length of time until return to work after surgery.