Adam L. Wollowick

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 >4 mm; Type B, a cancellous channel of 2 to 4 mm; Type C, a cortical channel of ≥2 mm; or Type D, a cortical or cancellous channel of <2 mm. Types B, 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 < 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.

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.

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

STUDY 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% < BMI < 85%), overweight (n = 25) (BMI > 85% to 95%), and obese (n = 38) (BMI > 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.

Complications associated with surgical repair of syndromic scoliosis

BackgroundThere are a number of syndromes that have historically been associated with scoliosis e.g.: Marfan, Down, and Neurofibromatosis. These syndromes have been grouped together as one etiology of scoliosis, known as syndromic scoliosis. While multiple studies indicate that these patients are at high risk for perioperative complications, there is a paucity of literature regarding the collective complication rates and surgical needs of this population.MethodsPubMed and Embase databases were searched for literature encompassing the surgical complications associated with the surgical management of patients undergoing correction of scoliosis in the syndromic scoliosis population. Following exclusion criteria, 24 articles were analyzed for data regarding these complications.ResultsThe collective complication rates and findings of these articles were categorized based on specific syndrome. The rates and types of complications for each syndrome and the special needs of patients with each syndrome are discussed. Several complication trends of note were observed, including but not limited to the universally nearly high rate of wound infections (>5% in each group), high rate of pulmonary complications in patients with Rett syndrome (29.2%), high rate (>10%) of dural tears in Marfan and Ehlers-Danlos syndrome patients, high rate (>20%) of implant failure in Down and Prader-Willi syndrome patients, and high rate (>25%) of pseudarthrosis in Down and Ehlers-Danlos patients.ConclusionsThough these syndromes have been classically grouped together under the umbrella term “syndromic,” there may be specific needs for patients with each of these ailments. Given the high rate of complications, further research is necessary to understand the unique needs for each of these patient groups in the preoperative, intraoperative, and postoperative settings.

Timing of surgical staging in adult spinal deformity surgery: is later better?

COMMENTARY ON Hassanzadeh H, Gjolaj JP, El Dafrawy MH, et al. The timing of surgical staging has a significant impact on the complications and functional outcomes of adult spinal deformity surgery. Spine J 2013;13:1717-22 (in this issue).