Minimally invasive scoliosis surgery: an innovative technique in patients with adolescent idiopathic scoliosis

Minimally invasive spine surgery is becoming more common in the treatment of adult lumbar degenerative disorders. Minimally invasive techniques have been utilized for multilevel pathology, including adult lumbar degenerative scoliosis. The next logical step is to apply minimally invasive surgical techniques to the treatment of adolescent idiopathic scoliosis (AIS). However, there are significant technical challenges of performing minimally invasive surgery on this patient population. For more than two years, we have been utilizing minimally invasive spine surgery techniques in patients with adolescent idiopathic scoliosis. We have developed the present technique to allow for utilization of all standard reduction maneuvers through three small midline skin incisions. Our technique allows easy passage of contoured rods, placement of pedicle screws without image guidance, and allows adequate facet osteotomy to enable fusion. There are multiple potential advantages of this technique, including: less blood loss, shorter hospital stay, earlier mobilization, and relatively less pain and need for pain medication. The operative time needed to complete this surgery is longer. We feel that a minimally invasive approach, although technically challenging, is a feasible option in patients with adolescent idiopathic scoliosis. Although there are multiple perceived benefits, long term data is needed before it can be recommended for routine use

Spondylolisthesis: Diagnosis, Non-Surgical Management, and Surgical Technique

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Increased Risk of Infection in Obese Adolescents After Pedicle Screw Instrumentation for Idiopathic Scoliosis

AbstractStudy Design Original research. Objective To evaluate perioperative risk factors associated with obesity in children undergoing posterior spinal fusion for adolescent idiopathic scoliosis. The authors hypothesized that patients with a high body mass index (BMI) percentile would be associated with increased morbidity as measured by various intraoperative parameters. Summary of Background Data Few studies have evaluated the effects of increased BMI in children undergoing surgery. Adolescent idiopathic scoliosis represents 80% of idiopathic scoliosis cases and is the most common indication for surgery. Methods Patients were divided into 3 groups: normal weight (n = 144) (5% \u3c BMI \u3c 85%), overweight (n = 25) (BMI \u3e 85% to 95%), and obese (n = 38) (BMI \u3e 95%). Patients with BMI less than 5% were excluded from this study because they were underweight. Perioperative data were collected and analyzed based on differences between groups. Results A total of 207 patients were included in this study. There was a significant difference in the length of anesthesia (p = .032). The rate of infection was 11% in the obese group, 12% in the overweight group, and 3% in the normal weight group (p = .03). Conclusions Even with pedicle screw instrumentation, the researchers saw an increase in infection in overweight and obese patients. Patients should be counseled before surgery for weight loss to limit surgical complications such as possible risk of postoperative wound infection

Prevalence, Distribution, and Surgical Relevance of Abnormal Pedicles in Spines with Adolescent Idiopathic Scoliosis vs. No Deformity: A CT-Based Study

BACKGROUND: A thorough understanding of pedicle morphology is necessary for pedicle screw placement. Previous studies classifying pedicle morphology, to our knowledge, have neither discussed the range of abnormal morphology nor correlated patient or curve characteristics with abnormal morphology to identify at-risk pedicles.METHODS: With the use of computed tomography (CT) images, we analyzed a total of 6116 pedicles from ninety-five patients without spinal deformity (forty-two females and fifty-three males) and ninety-one patients with adolescent idiopathic scoliosis (AIS) (sixty-eight females and twenty-three males). Pedicle morphology was classified as: Type A, a cancellous channel of \u3e4 mm; Type B, a cancellous channel of 2 to 4 mm; Type C, a cortical channel of \u3e/=2 mm; or Type D, a cortical or cancellous channel ofB, C, and D were defined as abnormal. Patient demographic data and pedicle distribution were assessed for prevalence and likelihood of abnormal pedicle morphology. Postoperative CT images from fifty-nine patients with AIS were used to assess screw placement.RESULTS: There was a significantly higher rate of abnormal pedicles in patients with AIS (p = 0.001). More abnormal pedicles were located in the thoracic spine compared with the lumbar spine both in patients without deformity (13.3% versus 2.0%) and patients with AIS (31.9% versus 2.4%). Significantly more abnormal pedicles were located on the concavity (p \u3c 0.001), within the periapical region (p = 0.02), and on the apex of the curve (p = 0.03). Three times as many pedicle screws were misplaced in abnormal pedicles compared with normal pedicles (21% versus 7%).CONCLUSIONS: Our study found a significantly higher prevalence of abnormal pedicles in the patients with AIS. Of the abnormal pedicles in these patients, most were in the thoracic spine, on the concave side, and in the periapical and apical regions.CLINICAL RELEVANCE: Knowledge of abnormal pedicles may enable surgeons to anticipate and plan for difficult screw placement and further decrease risk to the patient

Scoliosis Surgery in Patients With Adolescent Idiopathic Scoliosis Does Not Alter Lung Volume

Study Design. Retrospective study of surgically treated patients with adolescent idiopathic scoliosis. Objective. To determine the change in lung volume after the surgical correction of scoliosis using a volumetric reconstruction of lung volume from computed tomographic (CT) scans. Summary of Background Data. Previously published studies have shown that pulmonary function tests improve after scoliosis correction; however, these results are not consistent. CT-based volumetric studies in patients with scoliosis have previously shown differences in lung volume and lung volume ratio when compared with a normal population. To date, no study exists that analyzes changes in these parameters after scoliosis surgery. Methods. A total of 29 patients with adolescent idiopathic scoliosis who had pre-and postoperative CT scans on file were included in this study. Three-dimensional lung volume reconstruction was performed (TeraRecon software, TeraRecon, Inc., Foster City, CA). Appropriate masking methods were used to isolate the lung tissue. Total lung volumes, left and right lung volumes, and left/right lung volume ratio were obtained from the pre-and postoperative CT scans. Hemithoracic symmetry, pre-and postoperative Cobb angle, and kyphosis were also calculated. Results. Neither total lung volume nor left/right lung volume ratio changed significantly postoperatively. Surgery did not significantly change total lung volume (P = 0.87), right lung volume (P = 0.69), left lung volume (P = 0.70), or the ratio between right and left lung volumes (P = 0.87). Hemithoracic asymmetry was significantly improved (P \u3c 0.001). Median preoperative major Cobb angle was 53.2 degrees and median preoperative kyphosis was 32.8 degrees. Postoperatively, the median major Cobb angle was 15.0 degrees, resulting in a 70% Cobb correction, and mean postoperative kyphosis was 31.1 degrees. Conclusion. Corrective scoliosis surgery does not alter total lung volume or the ratio of right-to-left lung volume. Deformity correction leads to an improvement in the symmetry of the thoracic architecture and costovertebral joint mechanics, as evidenced by the improved hemithoracic asymmetry. Thus, the change in pulmonary function tests, which has been previously documented, may be a dynamic rather than a static phenomenon

Pedicle Screws Adjacent to the Great Vessels or Viscera A Study of 2132 Pedicle Screws in Pediatric Spine Deformity

Study Design: A retrospective study. Objective: To determine the incidence of pedicle screws close to vital structures and to identify patient or curve characteristics that increase the risk of screw misplacement. Summary and Background: Most pedicle screw misplacements are asymptomatic, thus they are frequently undetected. This study identifies the rate of screw placement in proximity to vital structures using postoperative computed tomography scans. Methods: A total of 2132 screws in 101 patients, who underwent posterior spinal fusion for spinal deformity, were reviewed. Screws adjacent to great vessels and viscera were identified and evaluated. Patients with screws at risk (group B) were compared with patients without screws at risk (group A). Patient and curve characteristics were analyzed to determine whether a correlation with screw misplacement exists. Results: A total of 40 at risk screws (similar to 2%) were identified in 25 patients (similar to 25%). These 40 screws were in proximity to the aorta (31), left subclavian artery (1), esophagus (3), trachea (3), pleura (1), and diaphragm (1). Of the 31 screws close to the aorta, 10 screws in 6 patients were impinging or distorting the aortic wall. One hundred percent of misplaced screws were in the thoracic spine, 50% were misplaced laterally, 50% were 35 mm long, 57.5% were in pedicles with normal morphology, and 75% were in curves between 40 and 70 degrees. Median screw misplacement rate was 10% in group A and 13% in group B. Adjusted for age and preoperative Cobb angle, patients with a higher misplacement rate were more likely to have screws adjacent to vital organs [adjusted odds ratio: 1.06 (95% confidence interval, 1.01-1.13), P=0.033]. Conclusions: Although only a small number of screws were at risk, they occurred in a large percentage of patients (25%). A single at-risk screw causes a significant complication for the patient. Postoperative imaging beyond routine x-rays may be needed to detect at-risk screws in asymptomatic patients

Minimally Invasive Surgery in Patients with Adolescent Idiopathic Scoliosis: Is it Better than the Standard Approach? A Two Year Follow-Up Study

STUDY DESIGN:: This is a retrospective controlled study. OBJECTIVE:: To compare the safety and efficacy of a minimally invasive approach (MIS) for the surgical management of adolescent idiopathic scoliosis (AIS) to the standard open posterior approach (PSF). SUMMARY OF BACKGROUND DATA:: MIS approaches offer the potential to reduce soft-tissue trauma, intraoperative blood loss, and surgical site infection. Thus far, MIS has been successfully utilized for the surgical correction of multilevel spine pathology in adults. It is not yet known if these results can be replicated in the surgical management of AIS. METHODS:: Seven MIS patients were compared to 15 PSF patients using minimum two-year follow-up data. Parameters studied included preoperative patient and deformity characteristics, perioperative parameters, extent of deformity correction, and complications. Data were compared using Mann-Whitney tests for continuous variables and Fisher\u27s exact tests for categorical variables. RESULTS:: The MIS and PSF groups were similar for all preoperative characteristics collected (P\u3e0.05). MIS patients had fewer fixation points (P=0.015), but a longer median operative time (P=0.011). There was no significant difference in estimated blood loss (EBL) (P=0.051), EBL/fixation point (P=0.204), or amount of fluids administered (P=0.888). Postoperative recovery did not differ between the two groups in number of ICU days (P=0.362), length of hospital stay (P=0.472), time to mobilization (P=1.00), VAS pain scores (P=0.698), or PCA (P=1.00). The MIS technique had similar deformity correction, screw placement accuracy, and fusion status when compared to the PSF group. CONCLUSION:: The short-term advantages seen in MIS for adult scoliosis were not as obvious in our series. Despite our findings of similar deformity correction and adequate fusion, concerns regarding quality of fusion, learning curve, and instrumentation persist. MIS surgery is an innovative treatment for AIS that is technically feasible; however, its advantages in the treatment of AIS are currently difficult to define