Acke Ohlin

A prospective study of brace treatment versus observation alone in adolescent idiopathic scoliosis: a follow-up mean of 16 years after maturity

Study Design. The Swedish patients included in the previous SRS brace study were invited to take part in a long-term follow-up. Objective. To investigate the rate of scoliosis surgery and progression of curves from baseline as well as after maturity. Summary of Background Data. Brace treatment was shown to be superior to electrical muscle stimulation, as well as observation alone, in the original SRS brace study. Few other studies have shown that brace treatment is effective in the treatment of scoliosis. Methods. Of 106 patients, 41 in Malmö (all Boston brace treatment) and 65 in Göteborg (observation alone as the intention to treat), 87% attended the follow-up, including radiography and chart review. All radiographs were (re)measured for curve size (Cobb method) by an unbiased examiner. Searching in the mandatory national database for performed surgery identified patients who had undergone surgery after maturity. Results. The mean follow-up time was 16 years and the mean age at follow-up was 32 years The 2 treatment groups had equal curve size at inclusion. The curve size of patients who were treated with a brace from the start was reduced by 6° during treatment, but the curve size returned to the same level during the follow-up period. No patients who were primarily braced went on to undergo surgery. In patients with observation alone as the intention to treat, 20% were braced during adolescence due to progression and another 10% underwent surgery. Seventy percent were only observed and increased by 6° from inclusion until now. No patients underwent surgery after maturity. Progression was related to premenarchal status. Conclusion. The curves of patients with adolescent idiopathic scoliosis with a moderate or smaller size at maturity did not deteriorate beyond their original curve size at the 16-year follow-up. No patients treated primarily with a brace went on to undergo surgery, whereas 6 patients (10%) in the observation group required surgery during adolescence compared with none after maturity. Curve progression was related to immaturity.

Complications after transpedicular stabilization of the spine. A survivorship analysis of 163 cases

Objectives The authors studied complications of transpedicular stabilization methods. Summary of Background Data One hundred and sixty-three consecutive transpedicular stabilization procedures were performed between January 1987 and December 1991. The indications for stabilization were trauma (33 cases), metastatic spinal disorder (30 cases), spinal stenosis (33 cases), spondylolisthesis (27 cases), ankylosing spondylitis (6 cases), low back pain (22 cases), and miscellaneous (12 cases). Methods, Patients records and the entire series of radiographs for each case were scrutinized by independent observers. All per-and postoperative complications, including implant loosening and fatigue, were recorded. Clinical and radiographic survivorship analyses of the implants were performed. Results Early complications were unusual and none were associated with permanent morbidity. The probability of not having the implant removed in the first postoperative year was 85%. There was a 40% risk of radiographic failure, defined as loosening or implant fatigue, at 6 months. The outcome was more favorable in cases in which anterior vertebral interbody fusion was also performed. Conclusions Transpedicular fixation is a safe procedure with a low incidence of serious per- and early postoperative complications. The mechanical durability of transpedicular fixators used alone is a cause for concern.

Body Appearance and Quality of Life in Adult Patients With Adolescent Idiopathic Scoliosis Treated With a Brace or Under Observation Alone During Adolescence

Study Design. The Scoliosis Research Society (SRS) brace study (published in the JBJS-A, 1995) was comprised of patients with adolescent idiopathic scoliosis with moderate curve sizes (25°–35°). Forty observed and 37 braced patients (77% of the original group) attended a follow-up, a mean of 16 years after onset of maturity. Objective. To analyze whether the subjectively evaluated present body appearance affects outcome as measured by quality of life in adult patients, previously treated by observation alone (nonbraced) or with a brace during adolescence. Summary of Background Data. Few reports exist where validated outcome measures for body appearance have been used. Methods. Two quality-of-life questionnaires, the Scoliosis Research Society-22 (SRS-22) questionnaire and the 36-Item Short-Form Survey Instrument (SF-36), were answered. The patients opinion on body appearance was evaluated pictorially (i.e., sketches) using the spinal appearance questionnaire, in which 7 aspects of asymmetry are graded. These scores were compared with curve sizes, scoliometer measurements for grading trunk asymmetry, and quality-of-life measures. Results. At follow-up, both groups were similar in terms of age (mean = 32 years) and curve size (mean = 35°). Distortion was inversely related to SRS-22 total score and satisfaction/dissatisfaction with management subscore, but not related to the SRS-22 function subscore. No difference was found between the groups in terms of trunk rotation, where the means were 10.7° and 10.8° for the nonbraced and braced patients, respectively. The nonbraced patients estimated that their body appearance was significantly less distorted than the braced patients (mean = 12.9 and 15.0, respectively; P = 0.0028). Conclusion. Patients who experienced less body asymmetry were more satisfied with treatment and had a better quality of life. In spite of similar curve sizes and trunk rotation in both groups, the nonbraced patients felt that their body appearance was less distorted than that of the braced patients.

Health-Related Quality of Life in Untreated Versus Brace-Treated Patients With Adolescent Idiopathic Scoliosis: A Long-term Follow-up.

Study Design. The previous Scoliosis Research Society brace study (JBJS-A, 1995) included patients with adolescent idiopathic scoliosis (AIS) with moderate curve sizes (25°–35°). The Swedish patients in this study were examined in a long-term follow-up. Objective. The aim was to analyze and compare quality of life in adulthood between AIS patients who were only observed or treated with a brace during adolescence. Summary of Background Data. Quality of life as measured by the SRS-22 has not previously been presented for adult untreated AIS patients. Methods. Forty patients who were only observed (due to a curve increase of less than 6° until maturity), and 37 brace-treated patients attended the complete follow-up, including clinical and radiologic examination, and answered 2 quality of life questionnaires (SRS-22 and Short Form-36 [SF-36]). Results. No differences were found between the groups in terms of age at follow-up (mean: 32 years), follow-up time after maturity (mean: 16.0 years), and curve size at inclusion (mean: 30°) or at follow-up (mean: 35°). The SRS-22/total score was a mean of 4.2 for braced patients and 4.1 for only observed patients. Neither total scores/subscales of the SRS-22 or SF-36 differed significantly between the groups. For the SF-36, no differences in relation to the Swedish age-matched norm scales were found for either group. Conclusion. Patients with moderate AIS report good quality of life in their 30s, as measured by both the SRS-22 and SF-36, regardless of whether they received no active treatment or were brace treated during adolescence. Neither of the groups displayed any difference compared with the age-matched norm groups for the SF-36.

Reliability of Low-Radiation Dose CT in the Assessment of Screw Placement After Posterior Scoliosis Surgery, Evaluated With a New Grading System

Study Design. A retrospective study. Objective. To evaluate the reliability of computed tomography (CT) with low radiation dose in the assessment of implant status in patients with adolescent idiopathic scoliosis (AIS). Summary of Background Data. The use of all-pedicle screw construct in scoliosis corrective surgery continues to gain increasing popularity since their introduction 1994 although their use in the thoracic spine carries a potential risk for neurovascular complications. CT is the method widely used to evaluate screw placement. Methods. Retrospective analysis of 46 consecutive low-dose spine CT in patients with AIS after posterior corrective surgery. Status of 809 titanium screws (642 thoracic) was evaluated. The degree of interobserver and intraobserver agreements about implant status was used as an indicator of the reliability of the low-dose spine CT in the assessment of accuracy of pedicle screw insertion. A new grading system has been developed for this purpose. Five types of misplacement have been evaluated: lateral, medial, and anterior cortical perforations; endplate perforation; and foraminal perforation. Results. The analysis has shown a substantial interobserver and intraobserver agreements (&kgr;: 0.69 and 0.76, respectively) in differentiating pedicle screws with acceptable placement from screws with partial or total cortical perforation. None of the examinations was subjectively classified as unreliable. Conclusion. The study has shown that low-dose spine CT is a reliable method in evaluating screw placement in patients with AIS after posterior scoliosis surgery with titanium implants, using the here proposed grading system. The new grading system of screw misplacement was feasible and in line with the general agreement about the harmlessness of misplacement with minor pedicle breach. The reliability of low-dose spine CT in evaluation of lateral and medial cortical perforations was substantial. To reduce the radiation load, the postoperative assessment of titanium implants should be performed with low-dose CT.

Vertebroplasty and kyphoplasty: New treatment strategies for fractures in the osteoporotic spine.

During the last decade, two new treatment modalities for osteoporotic vertebral fractures have gained more interest: percutaneous vertebroplasty and kyphoplasty. The techniques and the short-term clinical results and complications have been presented but there is no scientific evidence-based information regarding the efficacy of the procedures, such as randomized controlled trials (RCT). Instead, we have to rely on prospective and retrospective uncontrolled short-term observational studies and case-control studies. These studies have shown consistently that the short-term results after the procedures are favorable as regards both pain relief and functional status. It is currently unknown, however, whether a vertebroplasty or a kyphoplasty gives a better outcome than nonoperative treatment, and whether the long-term results are as favorable as the short-term results.

Socket wear assessment: A comparison of three different radiographic methods**

Three different methods to measure wear of total hip sockets from plain radiographs were compared with the results obtained by direct assessment of the internal deformity of 28 retrieved sockets by means of a coordinate measuring machine. The values obtained by the uni-radiographic, the duo-radiographic, and the radiographic methods based on the change of distance between the centers of the socket and the prosthetic head (CEN) all correlated significantly with the standard obtained by the coordinate measuring machine, provided the sockets were not loose. The most accurate radiographic measurements were obtained with the CEN method. A prerequisite for a reliable estimation of socket wear rate is that it be based on observations of radiographically intact sockets.

Spatial facilitation of motor evoked responses in monitoring during spinal surgery

During spinal cord monitoring, motor responses in the tibialis anterior muscles were recorded on transcranial electrical stimulation of the motor cortex. In order to facilitate the responses, the cortical stimulus was preceded by a train of stimuli to the foot sole within the receptive field of the withdrawal reflex of the tibialis anterior muscle. This cutaneous input provides a spatial facilitation of the cortically elicited response. When the stimulus interval was 50-100 ms, large and reliable responses were seen in most cases.

Optimization of Radiation Exposure and Image Quality of the Cone-beam O-arm Intraoperative Imaging System in Spinal Surgery.

Study Design Retrospective study. Objectives To optimize the radiation doses and image quality for the cone-beam O-arm surgical imaging system in spinal surgery. Summary of Background Neurovascular compromise has been reported after screw misplacement during thoracic pedicle screw insertion. The use of O-arm with or without navigation system during spinal surgery has been shown to lower the rate of screw misplacement. The main drawback of such imaging surgical systems is the high radiation exposure. Methods Chest phantom and cadaveric pig spine were examined on the O-arm with different scan settings: 2 were recommended by the O-arm manufacturer (120 kV/320 mAs, and 120 kV/128 mAs), and 3 low-dose settings (80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs). The radiation doses were estimated by Monte Carlo calculations. Objective evaluation of image quality included interobserver agreement in the measurement of pedicular width in chest phantom and assessment of screw placement in cadaveric pig spine. Results The effective dose/cm for 120 kV/320 mAs scan was 13, 26, and 69 times higher than those delivered with 80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs scans, respectively. Images with 60 kV/40 mAs were unreliable. Images with 80 kV/80 mAs were considered reliable with good interobserver agreement when measuring the pedicular width (random error 0.38 mm and intraclass correlation coefficient 0.979) and almost perfect agreement when evaluating the screw placement (&kgr; value 0.86). Conclusions The radiation doses of the O-arm system can be reduced 5 to 13 times without negative impact on image quality with regard to information required for spinal surgery.

The pathogenesis of loosening of total hip arthroplasties. The production of factors by periprosthetic tissues that stimulate in vitro bone resorption.

The production of factors capable of stimulating bone resorption in the newly formed periprosthetic capsule and in the bone-cement membrane obtained from patients reoperated due to aseptic loosening of cemented total hip prostheses was studied using organ culture techniques. Addition of culture media conditioned by membranes from six patients and bone-cement membranes from two patients to the mouse calvarial cultures resulted in a significantly increased release of calcium. The effect of capsule-conditioned media on calcium release was dose- and time-dependent and significantly reduced by the osteoclast inhibitor of calcitonin. Histologic analysis of bones at the end of the culture period showed that capsule-conditioned media enhanced the breakdown of mineralized bone and increased the number of osteoclasts. The observations showed that newly formed periprosthetic tissues from patients with loose total hip arthroplasties (THAs) can produce one or several factors that stimulate bone resorption in vitro by an osteoclast-mediated mechanism. Not only mechanical failure but also biologic reactions in the periprosthetic tissues eventually lead to osteoclast activation and may contribute to the loosening of THAs.