Biomedical subjects

Patricia G Anderson

Publications and source records attributed to Patricia G Anderson.

10 recordsLinked to original sources

PubMed2006

A new CT scan method for measuring the tibial tubercle trochlear groove distance in patellar instability.

Patellar malalignment leading to objective or potential patella instability can be caused by tibial tuberosity lateralisation. This can be treated with a tuberosity medialisation. CT scan measurements are needed to assess the tibial tubercle trochlear groove distance. When using the previously described methods to determine this distance it can be difficult to determine the anatomical structures on the maximum intensity projection images, and this can lead to measurement error. This study was designed to compare the reliability of a new computer based CT measurement to the previously described method to determine the tibial tubercle trochlear groove distance. For each method, four observers measured each of 50 knees twice. The inter- and intra-observer variability for the conventional method and a new method were determined. Using the conventional method, the number of knees for which the difference between the aggregate mean of all eight measurements and the mean of duplicate measurements per observer greater than 2 mm varied among the observers between 7 and 24 for the 50 knees, while this variation between four and seven for the same 50 knees using the new method. The limits of reproducibility based on measurements from the four different observers improved by 25%, indicating that the measurement error is considerably smaller with the new method. We advise using this more accurate method to improve the selection of patients for a tuberosity medialisation.

Cohort Studies↗

PubMed2006

Conventional radiography cannot replace CT scanning in detecting tibial tubercle lateralisation.

Patellar instability can be caused by an excessive lateral distance between the anterior tibial tubercle and the trochlear groove (TT-TG). This study was designed to compare the TT-TG in reformatted computed tomography to the TT-TG on a 30 degrees axial conventional radiograph (CR) using lead markers to visualize the tibial tubercle and epicondyles. This is the first report on the use of lead markers for determining the TT-TG. Seven symptomatic knees in five patients (mean age 25 years, standard deviation 8.0 years) were investigated. Results showed that the tibial tubercle could be detected on 30 degrees axial CR by a lead marker. Determining the TT-TG however proved to be difficult. A good intra- and interobserver reliability (ICC >0.86) but large measurement error for the axial CR compared to CT was measured (Limits of Reproducibility as quantification of the measurement error was 18 mm for axial CR and 4 mm for CT). Because of the large measurement error for axial CR, the study was terminated after seven symptomatic knees. Positioning of the patient and markers, especially the tibial tubercle marker, probably are important factors leading to the large measurement error. Therefore, axial CR cannot replace CT to detect a pathological tubercle trochlear groove distance.

Adolescent↗

PubMed2006

The value of a pantaloon cast test in surgical decision making for chronic low back pain patients: a systematic review of the literature supplemented with a prospective cohort study.

The results of lumbar fusion in chronic low back pain (LBP) patients vary considerably, and there is a need for proper patient selection. Lumbosacral orthoses have been widely used to predict outcome, however, with little scientific support. The aim of the present study was to determine the value of a pantaloon cast test in selecting chronic LBP patients for lumbar fusion or conservative management. First, a systematic review of the literature was carried out in which two independent reviewers identified studies in Medline, Cochrane and Current Contents databases. Three papers met the selection criteria. In the only study with a control group, a significantly better outcome after fusion compared to conservative treatment was found in patients who reported significant pain relief while in a cast (i.e. a positive cast test). The results of lumbar fusion, however, were not significantly different for patients with a positive and those with a negative cast test. In addition to the review, a clinical cohort study of 257 LBP patients, who had been allocated to either lumbar fusion or conservative management by a temporary external transpedicular fixation trial, was performed. Prior to allocation, all had undergone a pantaloon cast test. Patients with no history of prior spine surgery and with a positive pantaloon cast test had a better outcome after lumbar fusion than those treated conservatively (P = 0.002, chi (2 )test). In patients with previous spine operations the outcomes were poor and the test was of no value. From the literature and the present patient cohort, it was concluded that only in chronic LBP patients without prior spine surgery, a pantaloon cast test with substantial pain relief suggests a favorable outcome of lumbar fusion compared to conservative management. The test has no value in patients who have had previous spine surgery.

Adult↗

PubMed2005

Temporary external transpedicular fixation of the lumbosacral spine: a prospective, longitudinal study in 330 patients.

STUDY DESIGN: In this study, 330 patients with incapacitating low back pain underwent temporary external transpedicular fixation (TETF) of the lumbosacral spine in a prospective trial. OBJECTIVE: To evaluate TETF as a test for selecting suitable candidates for segmental spinal fusion. SUMMARY OF BACKGROUND DATA: Few studies regarding TETF have been published, and contradictory results concerning predictive value and morbidity were reported. METHODS: All patients were tested with the external fixator in two different positions: fixation and nonfixation. Before and during the test and at follow-up examination, pain was assessed on a Visual Analogue Scale (VAS). The TETF test was considered to be positive if the VAS score in the fixation state was 30 or more points lower than in the nonfixation state. Hence, a positive test would imply the decision to perform segmental lumbosacral fusion. When the reduction was less than 30 points, the test was negative. Individual pain reduction and working capacity were taken as measure of outcome. RESULTS: Most of the patients in this study (62%) underwent spinal surgery previously. The positive and negative TETF groups were quite similar, but a large within-group variation was found. Within the fusion group of 123 patients, improvement in VAS scores and improvement in working capacity were not significantly better for the positive TETF group in comparison with the negative TETF group. CONCLUSION: In this heterogeneous group of chronic patients with low back pain, TETF of the spine (including a placebo trial) does not appear to be of value in selecting suitable candidates for spinal fusion.

Adult↗

PubMed2005

Spinal osteotomy in patients with ankylosing spondylitis: complications during first postoperative year.

STUDY DESIGN: A historic cohort to determine short-term complications after 115 corrective osteotomies of the cervical and lumbar spine in patients with ankylosing spondylitis. OBJECTIVES: To describe the nature of complications of spinal osteotomies and sequelae. SUMMARY OF BACKGROUND DATA: Little is known about the rate and nature of complications after spinal osteotomy in these patients. METHODS: A chart review of 106 patients (age, 21-82 years) was conducted. The following surgical techniques were performed: cervical-thoracic extending osteotomy at C6-Th1 (n = 22), lumbar closing-wedge osteotomy (n = 62), polysegmental lumbar osteotomy (n = 20), or a combined anterior-posterior lumbar correction (n = 11). RESULTS: Many complications (7.8% permanent neurologic deficit, 9.6% deep wound infections, and 10.4% major general complications) occurred after performing a spinal correction. Since 1998, there is a tendency for a lower rate of infections but a higher rate of neurologic and major general complications. Because of 27% deep wound infections and 18% major general complications, the technique of combined anterior and posterior surgery has been abandoned. CONCLUSION: High complication rates in this group of patients are partly due to the difficult surgery but also to the underlying disease. The surgery should be concentrated in specialized centers.

Adult↗

PubMed2005

Ten to twelve-year results with the Zweymüller cementless total hip prosthesis.

Between January 1987 and December 1990, 221 Zweymüller cementless total hip arthroplasties were performed in 211 patients with idiopathic osteoarthritis. A total of 136 patients (142 prostheses) were evaluated at a mean follow-up of 134 months (SD 9.5). The study group consisted of 78 Hochgezogen and 64 Stepless stem prostheses, all with a threaded titanium cup and ceramic head. No clinical and radiological differences were found between the 2 stem prostheses. Seven cups had been revised because of aseptic loosening; 17 cups showed radiolucent lines, osteolysis, or migration. Mean linear polyethylene wear of 105 (74%) cups was 0.46 mm (SD 0.27), with an annual wear of 0.04 mm (SD 0.02). Wear did not correlate with pain, cup migration, radiolucent lines, or osteolysis. Cumulative survival was 96%. Zweymüller cementless total hip arthroplasty showed good midterm results.

Aged↗

PubMed2004

Tricalcium phosphate granules or rigid wedge preforms in open wedge high tibial osteotomy: a radiological study with a new evaluation system.

The capacity of two forms of porous beta-tricalcium phosphate bone substitutes (TCP) to promote bone healing in open wedge high tibial osteotomy (OWHTO) was studied. We reviewed the X-rays of 27 osteotomies, with either TCP wedges or TCP granules as filling material, to compare the bone healing rates and bone remodelling, at specific postoperative intervals. A new radiologic rating system for OWHTO was created and tested for clinical applicability. All osteotomies healed uneventfully and complete resorption of TCP was demonstrated at 1 year postoperative in 85% (n = 23) of the procedures. In 44% (n = 10) of these 23 procedures, the osteotomy site was no longer visible. No difference in bone healing rate and bone remodelling was found when comparing the use of granules to a wedge, and no adverse effects of TCP were observed. The good inter- (k = 0.7) and intraobserver (k = 0.6) reliability of the new radiologic rating system enables clinical use. Good bone healing was found in OWHTO with both wedges and granules of TCP.

Adult↗

PubMed2003

Scheuermann kyphosis: the importance of tight hamstrings in the surgical correction.

STUDY DESIGN: A historic cohort study of the sagittal alignment in 33 consecutive patients with surgically corrected thoracic Scheuermann kyphosis. OBJECTIVES: To determine if postsurgical imbalance, sagittal malalignment, and decreased lumbar-pelvic range of motion in patients with thoracic Scheuermann kyphosis is related to tight hamstrings. SUMMARY OF BACKGROUND DATA: Tight hamstrings are a frequent sign in Scheuermann kyphosis. The importance of tight hamstrings in the surgical management of Scheuermann kyphosis has not yet been studied. METHODS: Thirty-three patients with Scheuermann kyphosis were managed by surgical correction and fusion. Tight hamstrings, lumbar-pelvic range of motion, and sagittal balance were evaluated. Sixteen patients had tight hamstrings, and 17 patients had nontight hamstrings. Hamstrings were considered tight if the popliteal angle was >30 degrees. RESULTS: Patients with tight hamstrings have a significantly greater risk of postoperative imbalance (P = 0.05), and these patients can only compensate for this risk by reducing their lumbar lordosis (P = 0.0227). Furthermore, the limitations in the lumbar and pelvic range of motion are predicted by tight hamstrings (P <or= 0.005). CONCLUSION: Tight hamstrings can be considered as an important factor in the surgical management of thoracic Scheuermann kyphosis. Tight hamstring patients can be classified as "lumbar compensators" and as such are prone to overcorrection and imbalance. Preoperative assessment of the lumbar-pelvic range of motion and tight hamstrings should therefore be advised. Extensive fusion of the lumbar segments might compromise the lumbar compensation mechanism and induces further risk of imbalance.

Adult↗

PubMed2002

Analysis of the sagittal plane after surgical management for Scheuermann's disease: a view on overcorrection and the use of an anterior release.

STUDY DESIGN: A historic cohort study was conducted to investigate surgical correction and sagittal alignment in 33 patients with thoracic Scheuermann's disease. OBJECTIVE: To evaluate kyphosis correction, correction loss, sagittal balance, and the effect of an anterior release. SUMMARY OF BACKGROUND DATA: Currently, both posterior and anteroposterior techniques seem to produce impressive corrections for Scheuermann's disease. However, few reports have been made on sagittal malalignment after surgery. METHODS: A cohort of 33 patients who had undergone surgery for their Scheuermann's kyphosis were reviewed: Group A: posterior technique (n = 16), Group B: anteroposterior technique (n = 17). Pre- and postoperative curve morphometry (Cobb, Ferguson, Voutsinas), balance (C7 plumb line), and Oswestry score were compared. RESULTS: The mean follow-up period was 4.5 +/- 2 years (range, 2-8.2 years). The mean preoperative kyphosis (Cobb) was 78.7 degrees +/- 8.9 degrees, and the mean postoperative kyphosis was 51.7 degrees +/- 10.3 degrees. At follow-up evaluation, the correction loss was 1,4 degrees +/- 3.9 degrees. There was no difference in curve morphometry, correction, sagittal balance, average age, and follow-up period between Groups A and B. One junctional kyphosis, in Group B, was noted. After surgery, all the patients were satisfied, and the Oswestry score showed significant improvement. No neurologic complications were observed. CONCLUSIONS: Good follow-up results included a 100% follow-up rate, adequate corrections, little correction loss, lower Oswestry scores, and a high satisfaction rate in both groups. The anteroposterior treatment did not influence the curve morphometry more than posterior fusion only. In reducing postoperative sagittal malalignment, the authors believe that surgical management should aim at a correction within the high normal kyphosis range of 40 degrees to 50 degrees, consequently providing good results and, particularly in flexible adolescents and young adults, minimizing the necessity for an anterior release.

Adolescent↗

PubMedDate not supplied

Anterior cervical interbody fusion with a titanium box cage: early radiological assessment of fusion and subsidence.

BACKGROUND CONTEXT: The use of stand-alone cervical interbody cages in anterior cervical discectomy with fusion (ACDF) has become popular, but high subsidence rates have been reported in the literature. PURPOSE: The authors present short-term radiological results of a titanium box cage with regard to fusion and subsidence. Reliable fusion and lack of subsidence may influence long-term clinical results. Early radiological data are necessary before implementation of this device on a larger scale can be accepted. STUDY DESIGN/SETTING: Retrospective radiological quality assessment study. PATIENT SAMPLE: ACDF using the titanium cage was performed in 71 consecutive patients at 106 levels. Diagnoses included cervical disc disease (57) and cervical spinal stenosis (14) after failed conservative treatment. OUTCOME MEASURES: Subsidence and kyphosis were assessed on lateral cervical radiographs made directly postoperative and at 3- and 6-month follow-up. At 6-month follow-up, lateral flexion-extension radiographs were made to assess fusion. METHODS: Subsidence of the cage was defined as a decrease in total vertical height of the two fused vertebral bodies as measured on the lateral cervical radiographs made 3 and 6 months postoperatively compared with the directly postoperative radiographs. Segmental kyphosis was measured as the angle between the posterior borders of the two vertebral bodies on the lateral radiograph. RESULTS: No patients were lost to follow-up. Fusion was achieved after 6 months in all patients. At 3 and 6 months postoperative the same 10 cages (each in a different patient) had subsided. The C6-C7 level was significantly more frequently involved compared with all other levels. A segmental kyphotic alignment was observed in five patients at the C6-C7 level and in one patient at the C4-C5 level. CONCLUSIONS: For patients with cervical disc disease, the high subsidence tendency of the cage into the end plate of predominantly C7 is a disturbing phenomenon found in this study. A modified cage design that improves and extends contact with the inferior surface could be expected to reduce subsidence into C7.

Adult↗