Correction Of Thoracic Deformity Research Articles

Wang procedure: Background, characteristics and application

Wang procedure is a new method to treat pectus excavatum. Before this operation, there was almost only one choice for the treatment of pectus excavatum, which was Nuss procedure. Nuss procedure is a great operation. However, due to obvious defects, improvement is needed. Since general improvement cannot eliminate some deep-rooted defects, the only way to completely eliminate these defects is to design a brand-new technique. It is against this background that Wang procedure came into being. A large number of clinical practices have shown that this operation not only has many advantages that Nuss procedure does not have, but also can be used in a variety of depression and complex deformities. The appearance of Wang procedure has completely changed the concept of thoracic deformity correction and promoted the progress of technology.

Halo-external fixator frame-assisted correction to treat severe kyphotic deformity in children younger than 4 years old

BACKGROUND: Severe kyphotic deformity in young children may have devastating outcomes when neglected. Halo-pelvic traction has been shown to be very effective as part of the treatment for severe kyphosis, but little is known about application of this technique in very young individuals. The aim of this case series was to provide novel insights into the surgical technique associated with halo-external fixator frame (HEFF) treatment for severe spinal deformity in patients younger than 4 years old, along with the associated radiologic outcomes and complications METHODS: Clinical and demographic characteristics including the duration in the HEFF, HEFF-associated change in kyphosis angle (KA) and final KA following definitive surgery were extracted from medical records RESULTS: Five female patients with a mean age of 36 months (range 30-44) were included. Three patients had thoracic spinal tuberculosis (mean KA 82°), one had lumbar spinal tuberculosis (KA 42°) and one had iatrogenic post-laminectomy cervical kyphosis (type 1 neurofibromatosis)(KA 112°). The HEFF was applied for a mean of six weeks and resulted in a mean thoracic deformity correction of 29° (38%), a lumbar correction of 23° (55%) and cervical correction of 47° (42%). Definitive surgery resulted in a further mean overall deformity correction of 28, and patients had a satisfactory KA angle (23° lordosis to 31° kyphosis) at the last follow-up. HEFF-associated complications included pin-site infection, pneumonia and frame dislodgement CONCLUSION: HEFF appears to be an effective method for correcting severe kyphotic spinal deformity in very young patients where other options are limited. It allows for independent mobilisation and can provide for spinal stabilisation while awaiting bony healing after definitive surgery. However, healthcare providers should be aware of the potential dangers of HEFF hardware, such as difficulty in establishing an airway due to the fixed position of the neck Level of evidence: Level 4

The application of local rotating flap and latissimus dorsi flap in thoracic deformity correction.

Wound healing problem is one of the main complications after correction of chest wall deformity. Orthopedic flap tissue repair technique has a clear significance in non-healing wound and defect wound and provides a new choice for poor wound healing after orthopedic surgery of chest wall deformity. To investigate, the application value of modified local rotary flap and latissimus dorsi myocutcutaneous flap in the treatment of poor wound healing after orthodontic treatment of chest wall deformity. A retrospective analysis was performed on patients who admitted to our department from August 2012 to November 2019 due to non-healing incision after surgery for thoracic deformity. Skin flap was selected according to the size of the wound surface, and the effect of skin flap repair was observed. The clinical data of the included patients were recorded, and the preoperative and postoperative wound conditions were evaluated. This study included 13 patients with chest wall deformity who received plastic surgery tissue using flap technique for wound repair, 11 cases used modified local rotation skin flap, and 2 cases used modified latissimus dorsi myocutaneous flap. The mean age of the 13 patients was 18.54±4.14years old, the mean body mass index (BMI) was 17.02±2.16kg/m2 , and the mean preoperative nonunion time of the incision was 64.77±93.01days. Five patients had positive bacteria culture on the wound surface, including 3 cases of Staphylococcus aureus, 1 case of Pseudomonas aeruginosa, and 1 case of Staphylococcus epidermidis. All the 13 patients achieved primary grade A healing. The modified local rotary flap and latissimus dorsi musculocutaneous flap have a significant effect on the postoperative correction of chest wall deformity, which can ensure wound healing while retaining the orthopedic plate to the maximum extent to ensure the effect of the correction.

A novel MRI-based classification of spinal cord shape and CSF presence at the curve apex to assess risk of intraoperative neuromonitoring data loss with thoracic spinal deformity correction.

Retrospective cohort. We present a simple classification system that is able to identify patients with increased odds of losing intraoperative neuromonitoring data during thoracic deformity correction. Type 3 spinal cords, with the cord deformed against the concave pedicle in the axial plane, have ×28 greater odds of losing monitoring data during surgery. Assess preoperative morphology of the spinal cord across the thoracic concavity to predict intraoperative loss of neuromonitoring data. 128 consecutive patients undergoing surgical correction of a thoracic deformity with pedicle screw/rod constructs were included. Spinal cords were classified into 3 types based on the appearance of the cord on the axial-T2 MRI at the apex of the curve. Type 1 is defined as a circular/symmetric cord with visible CSF between the cord and the apical concave pedicle/vertebral body. Type 2 is a circular/oval/symmetric cord with no visible CSF between the concave pedicle and the cord. Type 3 is a spinal cord that is flattened/deformed by the apical concave pedicle or vertebral body, with no intervening CSF (Fig.1). 128 patients were reviewed: 81 (63%) Type 1; 32 (25%) Type 2; and 12 (11.7%) Type 3 spinal cords. Lower extremity trans-cranial motor-evoked Potentials (MEPs) and/or somatosensory evoked potentials (SSEPs) were lost intraoperatively in 21 (16%) cases, with full recovery of data in 20 of those cases. On regression analysis, a Type 1 cord was protective against intraoperative data loss (OR = 0.17, p = 0.0003). Type 2 cords had no association with data loss (OR = 0.66, p = 0.49). Type 3 cords had significantly higher odds of intraoperative data loss (OR = 28.3, p < 0.0001). We present a new spinal cord risk classification scheme to identify patients with increased odds of losing spinal cord monitoring data with thoracic deformity correction. The odds of losing intraoperative MEPs/SSEPs are greater in type 3 spinal cords. III.

Thoracic Deformity Correction and Changes of Vital Capacity, Forced Expiratory Volume in 1 Second, and Expiratory Flow in Adolescent Idiopathic Scoliosis Five Years or More after Posterior Spinal Fusion with Thoracoplasty

Introduction The purpose of this study is to investigate thoracic deformity correction and pulmonary function changes in patients with adolescent idiopathic scoliosis (AIS) five years or more after undergoing posterior spinal fusion with thoracoplasty for correction of a thoracic deformity. Methods Subjects were 57 patients with AIS who underwent posterior spinal fusion between 2004 and 2010. 24 patients who had undergone thoracoplasty at least five years earlier agreed to participate in this research. X-rays, pulmonary function tests, and thoracic cage computed tomography (CT) were performed, and the Scoliosis Research Society Outcomes Questionnaire (SRS-22) was administered. CT axial images were used at the apex of the main thoracic (MT) curve. Apical vertebral rotation was evaluated using rotation angle to the sagittal plane (RAsag). Thoracic deformities were evaluated using the rib hump index (RHi) and the posterior hemithoracic symmetry ratio (PHSr). Results There were no significant differences between the preoperative and the final observation forced vital capacity (FVC) or the preoperative and the final observation %FVC. The forced expiratory volume in 1 s (FEV1) and %FEV1 were significantly improved at the final observation: FEV1 (preoperative: 1.88 L, final observation: 2.05 L, p = 0.045) and %FEV1 (preoperative: 57.1%, final observation: 66.2%, p = 0.001). FEV1/FVC was also significantly improved at the final observation (preoperative: 83.0%, final observation: 86.4%, p = 0.019). The peak expiratory flow (PEF) was significantly improved at the final observation (preoperative: 3.67 L/s, final observation: 4.38 L/s, p = 0.029). On the CT assessment for thoracic deformities, there were no significant changes in RAsag or RHi. PHSr was significantly increased at the final observation compared with the preoperative period. Conclusions With posterior spinal fusion in combination with thoracoplasty for AIS, although the correction of deformities was limited, the pulmonary function testing demonstrated the preservation of vital capacity (VC) and improvements in the forced expiratory volume in 1 s and expiratory flow.

Wednesday, September 26, 2018 1:00 PM – 2:00 PM Navigation and Intraoperative Monitoring: 44. A novel MRI-based classification of spinal cord shape and CSF presence at the curve apex to assess risk of intraoperative neuromonitoring data loss with thoracic spinal deformity correction

BACKGROUND CONTEXT Intraoperative loss of neuromonitoring data can be detrimental for both the patient and the surgeon. We propose a classification system to identify spinal cords at risk for data loss with thoracic deformity correction based on the preop axial MRI images at the curve apex. PURPOSE To test the hypothesis that the architecture of the spinal cord and amount of CSF on MRI at the thoracic apex can identify patients at risk for intraoperative loss of neuromonitoring data during spinal deformity correction. STUDY DESIGN/SETTING Review of thoracic deformity patients undergoing surgical correction at a single large academic center. PATIENT SAMPLE Thoracic deformity patients undergoing surgical correction. OUTCOME MEASURES Occurrence of intraoperative loss of trans-cranial neuromonitoring data. METHODS We reviewed 128 consecutive patients undergoing surgical correction of a thoracic deformity with pedicle screw/rod constructs. On preop MRI axial imaging at the apical concavity, three types of spinal cord/CSF architecture were defined. Type 1: circular cord with visible CSF between the cord and the apical concave pedicle. Type 2: circular cord but no visible CSF between it and the concave pedicle. Type 3: cord deformed against the apical concave pedicle, with no intervening CSF. RESULTS Of the 128 pts: 81 (63%) had Type 1; 32 (25%) Type 2; and 12 (11.7%) Type 3 spinal cords. Lower extremity transcranial motor-evoked potentials (TcMEPs) and/or somatosensory evoked potentials (SSEPs) were lost intraoperatively in 21 (16%) cases, with full recovery of data in 20 of those. On regression analysis, a Type 1 spinal cord was protective against intraoperative data loss (odds ratio = 0.17, p=.0003). A Type 2 spinal cord had no association with data loss (OR=0.66, p=.49). Type 3 spinal cord had significantly higher odds of intraoperative data loss (OR=28.3, p CONCLUSIONS This MRI-based spinal cord risk classification scheme identifies patients at risk of losing monitoring data during surgery. Patients with the spinal cord deformed against the apical concave pedicle (Type 3) have 28 times greater odds of losing monitoring data during surgery versus Type 1 (normal cord with adequate CSF) and Type 2 (normal cord without CSF between cord and concave pedicle). FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Change in Lung Volume Following Thoracoscopic Anterior Spinal Fusion Surgery: A 3-Dimensional Computed Tomography Investigation.

Lung volumes and thoracic anatomy were measured from low-dose computed tomography (CT) scans preoperatively and 2 years following thoracoscopic anterior spinal fusion (TASF) for adolescent idiopathic scoliosis (AIS). The aim of this study was to assess changes in lung volume after TASF surgical correction. AIS patients are known to have decreased pulmonary function as a consequence of their spinal and ribcage deformity. Several studies have evaluated changes in pulmonary function clinically after scoliosis correction surgery showing varied results. To date, there have been no published studies using CT to evaluate lung volume changes following TASF. Twenty-three female AIS patients with both pre- and 2 years postoperative low-dose CT scans were selected from an ethically approved, historical databank. Three-dimensional lung volumes were reconstructed to determine anatomical lung volumes. Right and left lung volumes, total lung volume, and right-to-left lung volume ratio were obtained as well as hemithoracic symmetry, to indicate the extent of thorax deformity. Cobb angle, rib hump, levels fused in surgery, and patient height were used for correlation analysis with the lung volume results. Left lung volume, total lung volume, and hemithoracic ratio all increased significantly 2 years after surgery. There was no significant change in right-to-left lung volume ratio (P = 0.36). Statistical regression found significant positive correlation between lung volume changes, reduction in Cobb angle, increase in height, and improvement in hemithoracic symmetry ratio. TASF resulted in a statistically significant increase in lung volume following surgery, as well as improvement in the symmetry of the thoracic architecture; however, the postoperative lung volumes remained in the lower 50th percentile relative to females without thoracic deformity. Furthermore, change in lung volume was significantly correlated with changes in Cobb angle, hemithoracic asymmetry, and increased patient height, which are important consequences of thoracic deformity correction surgery. 3.

How well do Radiologic Assessments of Truncal and Shoulder Balance Correlate With Cosmetic Assessment Indices in Lenke 1C Adolescent Idiopathic Scoliosis?

A correlation study. The primary objective was to determine the correlation between radiologic and cosmetic indices of trunk and shoulder balance before and after scoliosis surgery in Lenke 1C adolescent idiopathic scoliosis and to determine whether postoperative trunk shift is affiliated with worsening of the patients' cosmesis. Achieving a symmetrical appearance with truncal and shoulder balance is of prime importance to adolescent idiopathic scoliosis patients and their surgeons. However, surgeons prefer radiographic indices rather than measures of patients' clinical appearance. If radiographic indices are to be considered accurate depictions of the patient's cosmesis, radiologic and cosmetic indices must necessarily exhibit high association. Radiographic and cosmetic indices of trunk and shoulder balance, along with posterior trunk symmetry index, were measured preoperatively and 3 months postoperatively in 33 Lenke 1C scoliosis patients. Pearson correlation analysis was performed. Paired t test was used to determine significant changes in radiographic and cosmetic indices after surgery. Independent-sample t test was used for all intergroup analyses in trunk shift and no-trunk-shift groups. Correlation coefficients between radiologic and cosmetic indices ranged between -0.63 and 0.70 with thoracic apical vertebra-central sacral vertical line (AV-CSVL) distance and first rib angle showing consistent correlations with cosmetic trunk and cosmetic shoulder balance indices. Trunk shift, a postoperative iatrogenic phenomenon, was seen in 19 (58%) patients. These patients had higher preoperative thoracic AV-CSVL translation, thoracic apical vertebra-first thoracic vertebra (AV-T1) translation, thoracic deformity correction rate, AV-T1 correction rates, and shorter fusions compared with the no-trunk-shift group. Posterior trunk symmetry index worsened in trunk shift group and improved significantly (-7.94 vs. 16.53) in no-trunk-shift group. Significant association (P=0.004) was seen between radiographic and cosmetic trunk shift. Radiographic indices can only minisculely (r≤0.7) reflect cosmetic deformity in Lenke 1C scoliosis, which emphasizes not only the vulnerability of overreliance on radiographic indices but also the vital importance of clinical cosmetic evaluations. In particular, cosmetic shoulder height and angle are not represented by radiographic indices. However, radiograph trunk shift was significantly associated with cosmetic trunk shift in cosmetic pictures.

Cervical compensatory alignment changes following correction of adult thoracic deformity: a multicenter experience in 57 patients with a 2-year follow-up.

OBJECT Alignment changes in the cervical spine that occur following surgical correction for thoracic deformity remain poorly understood. The purpose of this study was to evaluate such changes in a cohort of adults with thoracic deformity treated surgically. METHODS The authors conducted a multicenter retrospective analysis of consecutive patients with thoracic deformity. Inclusion criteria for this study were as follows: corrective osteotomy for thoracic deformity, upper-most instrumented vertebra (UIV) between T-1 and T-4, lower-most instrumented vertebra (LIV) at or above L-5 (LIV ≥ L-5) or at the ilium (LIV-ilium), and a minimum radiographic follow-up of 2 years. Sagittal radiographic parameters were assessed preoperatively as well as at 3 months and 2 years postoperatively, including the C-7 sagittal vertical axis (SVA), C2-7 cervical lordosis (CL), C2-7 SVA, T-1 slope (T1S), T1S minus CL (T1S-CL), T2-12 thoracic kyphosis (TK), apical TK, lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), and sacral slope (SS). RESULTS Fifty-seven patients with a mean age of 49.1 ± 14.6 years met the study inclusion criteria. The preoperative prevalence of increased CL (CL > 15°) was 48.9%. Both 3-month and 2-year apical TK improved from baseline (p < 0.05, statistically significant). At the 2-year follow-up, only the C2-7 SVA increased significantly from baseline (p = 0.01), whereas LL decreased from baseline (p < 0.01). The prevalence of increased CL was 35.3% at 3 months and 47.8% at 2 years, which did not represent a significant change. Postoperative cervical alignment changes were not significantly different from preoperative values regardless of the LIV (LIV ≥ L-5 or LIV-ilium, p > 0.05 for both). In a subset of patients with a maximum TK ≥ 60° (35 patients) and 3-column osteotomy (38 patients), no significant postoperative cervical changes were seen. CONCLUSION Increased CL is common in adult spinal deformity patients with thoracic deformities and, unlike after lumbar corrective surgery, does not appear to normalize after thoracic corrective surgery. Cervical sagittal malalignment (C2-7 SVA) also increases postoperatively. Surgeons should be aware that spontaneous cervical alignment normalization might not occur following thoracic deformity correction.

Cervical Malalignment Persists Following Adult Thoracic Deformity Correction: A Multicenter Experience of 81 Patients with Two-Year Follow-Up

Cervical Malalignment Persists Following Adult Thoracic Deformity Correction: A Multicenter Experience of 81 Patients with Two-Year Follow-Up

The effect of screw head design on rod derotation in the correction of thoracolumbar spinal deformity

The use of fixed-axis pedicle screws for correction of thoracolumbar deformity in adult surgery is demanding because of the challenge of assembling the bent rod to the screw in order to achieve curve correction. Polyaxial screw designs, providing increased degrees of freedom at the screw-rod interface, were reported to be insufficient in achieving correction of thoracic deformity in the axial plane. Using a multisegment bovine calf spine model, this study investigated the ability of a new uniplanar screw design to achieve derotation correction of the vertebrae and maintain a degree of correction comparable to that of fixed-axis and polyaxial screw designs. Eighteen calf thoracolumbar spine segments from T-6 to L-1 (n = 6 per screw design) underwent bilateral facetectomies at the T9-11 levels and were instrumented bilaterally with pedicle screws and rods. To assess the efficacy of each screw design in imparting rotational correction, each instrumented level was tested under applied torsional moments designed to simulate the motion applied during derotation surgery. Once rotation was achieved, the whole spine was tested to assess the overall stiffness of the construct. The fixed-axis construct showed increased efficacy in imparting rotation compared with the uniplanar (115% increase, p > 0.05) and polyaxial (210% increase, p < 0.05) constructs. Uniplanar screws showed a 21% increase in torsional stiffness compared with the polyaxial screws, but this difference was not statistically significant. The design of screw heads plays a significant role in affecting the rotation of the vertebrae during the derotation procedure. Uniplanar screws may have the advantage of maintaining construct stiffness after derotation.

Anterior Correction of Spinal Scoliotic Deformity

Objective. To access the efficacy of surgical treatment of scoliosis using anterior approach. Material and Methods. Twenty four patients aged 9–18 years (22 females, 2 males) were operated on. Twelve patients had thoracic deformity, and 12 – thoracolumbar and lumbar. Correction was performed through anterior approach using thoracotomy and thoracophrenolumbotomy with single and double rod instrumentation. Results. Mean correction of thoracic deformity was 84 %, mean number of fixed vertebrae was 7. Mean correction of lumbar and thoracolumbar deformity was 74 %, mean number of fixed vertebrae – 6. In all cases a good sagittal alignment of the spine was achieved. Conclusion. Anterior correction is indicated for Lenke type I and V scoliotic deformity. Anterior instrumentation is feasible for thoracic deformity below 75°, and for thoracolumbar and lumbar – below 85°.

Evaluation of Postoperative Residual Spinal Deformity and Patient Outcome in Idiopathic Scoliosis Patients in Japan Using the Scoliosis Research Society Outcomes Instrument

This study clarifies the correlation between the components of the Scoliosis Research Society Outcomes Instrument (SRS-24) and the radiographic parameters after surgery in Japanese idiopathic scoliosis patients. To investigate the correlation between the magnitude of back deformity after scoliosis surgery and the components of the SRS-24. Patient outcomes for Japanese scoliosis patients using the SRS-24 have not been fully investigated. Idiopathic scoliosis patients (n = 81) who were treated with surgery and followed up for more than 2 years were evaluated. Radiographic examination included Cobb angle, rotation angle of apical vertebrae, and translation of the C7 vertebra from the center sacral line on the coronal plane. In addition, the score of one new question regarding postoperative scar was investigated and compared with that of the individual SRS-24 domains. A comparison of the SRS-24 and radiographic results revealed a significant inverse correlation between total pain and the postoperative correction of the rotation angle in the thoracic curve (rs = 0.27; P < 0.05). General self-image was inversely correlated with the Cobb angle (rs = -0.23; P < 0.05) and the rotation angle (rs = -0.30; P < 0.01) in the thoracic curve. Self-image after surgery was positively correlated with the correction degree of the thoracic Cobb angle (rs = 0.27; P < 0.05); 60% of patients had some concerns regarding postoperative scar, and the concerned patients demonstrated significantly lower scores in the pain and general self-image domains (P < 0.05) than the unconcerned patients did. Patients with a greater Cobb angle or rotation angle in the thoracic curve had a negative self-image. Self-image improved after surgery by greater correction of the thoracic Cobb angle. Thoracic scoliotic deformity with prominence should be substantially reduced by the surgical treatment to improve satisfaction rates and self-image regarding back appearance. Additionally, physicians should pay more attention to patients' concern regarding their postoperative scars to obtain better outcomes.

Randomized Clinical Study to Compare the Accuracy of Navigated and Non-Navigated Thoracic Pedicle Screws in Deformity Correction Surgeries

Randomized clinical trial (level I evidence). To compare the accuracy of non-navigation and Iso-C based navigation in pedicle screw fixation in thoracic spine deformities. Thoracic pedicle screw insertion for spinal deformity correction can be associated with increased pedicle breaches. Iso-C based navigation has been reported to improve the accuracy of pedicle screw placement, but its use in the presence of deformity has not been reported. Twenty-seven patients with scoliosis and 6 patients with kyphosis had a total of 478 thoracic pedicle screws. The average Cobb angle was 58.4 degrees +/- 8 degrees (range 50 degrees -80 degrees), and the mean kyphotic angle was 54.6 degrees +/- 4 degrees (range 51 degrees -76 degrees). By random allocation, 17 patients had screw insertion under navigation (242 screws) and 16 under fluoroscopic control (236 screws). The 2 groups were compared for accuracy of screw placement, time for screw insertion, and the number of times the C-arm had to be brought into the field. Two independent blinded observers determined accuracy using postoperative computed tomography assessments. There were 54 (23%) pedicle breaches in the non-navigation group as compared to only 5 (2%) in the navigation group (P < 0.001). Thirty-eight screws (16%) in the non-navigation group had penetrated the anterior or lateral cortex compared to 2 screws (0.8%) in the navigation group. Average screw insertion time in the non-navigation group was 4.61 +/- 1.05 minutes (range 1.8-6.5) compared to 2.37 +/- 0.72 minutes (range 1.16-4.5) in navigation group (P < 0.01). The C-arm had to be moved into the operation field on an average of 1.5 +/- 0.25 times (range 1-3) per screw. With single screening data, an average of 11.4 pedicles (range 9-14) could be visualized without necessity to bring the C-arm into operating field again. Iso-C navigation increases accuracy, and reduces surgical time and radiation in thoracic deformity correction surgeries.

The Role of the Sternum, Costosternal Articulations, Intervertebral Disc, and Facets in Thoracic Sagittal Plane Biomechanics

Eighteen human torsos were used in three experiments (A, B, and C) to determine the changes in sagittal motion due to three different sequences of three surgical releases. To investigate the relative effects of releasing the intervertebral disc, the costosternal joint, the sternum, and the facet joints on sagittal thoracic motion and the consequences of altering the sequence of the releases. The biomechanics of the thoracic spine are different from the cervical and lumbar spine particularly due to the ribs and sternum, which contribute to stability and control motion. The role of the sternum and costosternal articulation in the biomechanics of thoracic sagittal motion has not been well studied. The effects of releasing each of these structures, whether alone or with discectomy and/or facetectomy, is potentially relevant in the surgical correction of thoracic deformities, such as severe kyphosis, and in the biomechanics of thoracic fracture. In Experiment A, the release sequence was back to front: total facetectomy (T4-T8), then radical discectomy (T4-T8), then costosternal release, then sternal osteotomy. In Experiment B, the release sequence was front to back: sternal osteotomy, then costosternal release, then radical discectomy, and finally total facetectomy. In Experiment C, the release sequence was: radical discectomy, then sternal osteotomy, then costosternal release, then total facetectomy. The different sequences allowed separate analysis of each component and the synergistic patterns. In each of the three experiments, the torso was flexed then extended each time by an applied force (25 N) before and after each release. The extent of flexion and the extent of extension were measured each time and compared with the intact condition, after each release. The results obtained for sternal osteotomy were combined with the results obtained for costosternal release to give "sternal release." Radical discectomy provided the greatest increase (P < 0.05) in range of motion (ROM) compared with the other two single releases, no matter what the sequence. For paired release combinations, the radical discectomy and sternal release (as in Experiments B and C) provided a significant (P < 0.05) increase in total sagittal ROM compared with the combination of radical discectomy and total facetectomy (Experiment A). In Experiment A, sternal release accounted for 42% of the total sagittal ROM compared with only 26% related to the total facetectomy (Experiment B). In general, all of the releases allowed more extension than flexion. Sagittal plane motion in the thoracic spine is influenced by all three structures tested in this experiment. Overall, the radical discectomy provides the greatest increase in total ROM and in extension compared with the other two releases. The second most influential release is the combination of sternal osteotomy plus costosternal release (i.e., sternal release), particularly in extension (correction of kyphosis). When two releases are done in sequence, radical discectomy plus sternal release provides the greatest increase in total ROM and in extension. Overall, total facetectomy is the least effective release. These data have relevance for surgical strategies in the correction of thoracic kyphosis or lordosis and suggest a potential role for sternal osteotomy and costosternal release in severe and rigid upper thoracic kyphosis.

Measurement of thoracic deformities. A new technique giving objective and reproducible results.

Many operations have been evolved for correction of thoracic deformities. Comparisons of the results have been hampered by lack of a method sufficiently accurate to permit objective and reproducible measurements of the thoracic cage. A special measuring apparatus was, therefore, constructed and has proved to be satisfactorily accurate. The apparatus and its use are described.