Daniel J. Sucato

Risk factors for the development of delayed infections following posterior spinal fusion and instrumentation in adolescent idiopathic scoliosis patients.

Study Design. Retrospective comparison study of patients who had a delayed infection following a posterior spinal fusion and instrumentation (PSFI) for adolescent idiopathic scoliosis (AIS). Objective. To define risk factors for the development of delayed infections following PSFI for AIS by comparing those patients who developed this complication to a randomly selected group of patients who did not. Summary of Background Data. Despite studies reporting the incidence and treatment of delayed infection following PSFI for AIS, there are no studies analyzing risk factors for its occurrence. Methods. All patients who required treatment for delayed infections following PSFI for AIS were identified (infection group, n = 36). A random selection of patients who did not develop a delayed infection (no infection, n = 90) was made in a ratio of 3:1 (no infection/infection). The 2 groups were compared using statistical methods. Results. Parameters associated with the infection group included: presence of a significant medical history, surgeon, less surgical time, a more distal fusion level (16% infection rate with a thoracic LIV vs. 33% infection rate with a lumbar LIV), not using postoperative drains, and increased drainage when drains were used. Other factors associated with infection were use of a blood transfusion and when increasing units of transfusion were used. Multivariate logistic regression analysis identified 3 factors that remained statistically significant: 1) significant medical history, 2) receiving a blood transfusion, and 3) not using a postoperative drain. Factors that were not associated with delayed infection included body mass index, the number of anchor points used, use of allograft bone, and the total number of levels instrumented and antibiotic regimen. Conclusion. The occurrence of a delayed infection is most likely multifactorial and is related to a positive past medical history and the use of blood transfusions. Postoperative use of a drain may be important to avoid delayed infection.

Non-Neurologic Complications Following Surgery for Adolescent Idiopathic Scoliosis

BACKGROUNDnThe reported prevalence of non-neurologic complications following corrective surgery for adolescent idiopathic scoliosis ranges from 0% to 10%. However, most studies were retrospective evaluations of treatment techniques and did not focus solely on complications. The purpose of this study was to determine the prevalence of non-neurologic complications following surgery for adolescent idiopathic scoliosis and to identify preoperative and operative factors that can increase this risk.nnnMETHODSnThe demographic data, medical and surgical histories, and prevalence of non-neurologic complications were reviewed in a prospective cohort of 702 patients who had undergone corrective surgery for adolescent idiopathic scoliosis and were consecutively enrolled in a multicenter database.nnnRESULTSnThere were 556 female and 146 male patients. The mean age at the time of surgery was 14.25 years (range, eight to eighteen years). Five hundred and twenty-three patients had only posterior spinal surgery, 105 had only anterior spinal surgery, and seventy-four had a combined anterior and posterior procedure. There was a total of 108 complications in eighty-one patients, for an overall prevalence of 15.4%. There were ten respiratory complications (1.42%), six cases of excessive bleeding (0.85%), five wound infections (0.71%), and five cases of wound hematoma, seroma, or dehiscence (0.71%). Five patients, two with an early infection and three with late failure of the implant, required a reoperation. Factors that did not correlate with an increased prevalence of complications were age, body mass index, presence of cardiac or respiratory disease, previous surgery, pulmonary function, surgical approach, number of levels fused, graft material, use of a diaphragmatic incision, Lenke curve type, or region of the major curve. Although the number of patients with renal disease was small, these patients were 7.90 times more likely to have a non-neurologic complication. Increased blood loss as well as prolonged operative and anesthesia times were associated with a higher prevalence of non-neurologic complications.nnnCONCLUSIONSnThe prevalence of non-neurologic postoperative complications following surgery for correction of adolescent idiopathic scoliosis in this study was 15.4%. The few factors noted to significantly increase the rate of complications include a history of renal disease, increased operative blood loss, prolonged posterior surgery time, and prolonged anesthesia time.

The Spinal Appearance Questionnaire: Results of reliability, validity, and responsiveness testing in patients with idiopathic scoliosis

Study Design. Prospective, sequential enrollment. Objective. We report the development and testing of the Spinal Appearance Questionnaire (SAQ) for reliability, validity, and responsiveness in patients with idiopathic scoliosis. Summary of Background Data. The SAQ was designed to measure patients’ and their parents’ perception of their spinal deformity’s appearance using standardized drawings and questions. This study was designed to test the instrument’s psychometric properties. Methods. The SAQ was administered as a test-retest to idiopathic scoliosis patients and parents for reliability and initial validity assessment (Group I). It was then administered to patients before surgery and 1 year after surgery (Group II) for responsiveness and further validity testing. Finally, both the SAQ and SRS instruments were administered to adolescent idiopathic patients before surgery and 1 year after surgery (Group III) for comparison of the 2 instruments. Results. Group I: The individual scale items had good to excellent reliability (Spearman’s rho, 0.57–0.99) and high internal scale consistency (Cronbach’s alpha >0.7). The mean scale scores differentiated between curves greater than 30° and lesser curves (P < 0.01). Surgery improved scores compared with those with “surgery recommended.” Group II: The domains correlated with clinical and radiographic aspects of the deformity before surgery. All of the domains showed significant difference after surgery (P < 0.0001) and large effect size for all domains except for the patient chest domain. Group III: Both the SAQ and the SRS instruments had significant improvement in all of their domains except for the SRS Activity scale. The relative efficiency of the SAQ domains to the SRS appearance domain (the most responsive SRS domain) was greater for 5 SAQ domains. Conclusion. The SAQ is reliable, responsive to curve improvement, and shows strong evidence of validity. It provides more detail than the SRS in the appearance domain, and provides explanation of spinal deformity’s concerns and improvements.

The Position of the Aorta Relative to the Spine: A Comparison of Patients with and without Idiopathic Scoliosis

BACKGROUNDnThere is little information documenting the relationship of the aorta to the thoracic scoliotic spine. Recent studies have suggested that the ends of screws placed during an anterior spinal arthrodesis, and pedicle screws used for the treatment of right thoracic scoliosis, may be in proximity to the aorta. The purpose of this study was to analyze the anatomical relationship between the aorta and the spine in a comparison of patients with idiopathic right thoracic scoliosis and patients with a normal spine.nnnMETHODSnThirty-six patients with adolescent idiopathic scoliosis with a right thoracic curve and forty-three with a normal straight spine were studied. Radiographs were analyzed to determine the Cobb angle, the apex of the curve, and the apical vertebral rotation for the patients with scoliosis. Axial magnetic resonance images from the fourth thoracic vertebra to the third lumbar vertebra at the midvertebral body level were used to measure the distance from the aorta to the closest point of the vertebral body cortex, the distance from the posterior edge of the aorta to the spinal canal, and the aorta-vertebral angle.nnnRESULTSnNo differences were found between the groups with respect to age or sex distribution. For the scoliosis and normal groups, boys had greater average vertebral body width and depth for all levels than did girls (p < 0.05). For the scoliosis group, the most common apical vertebra was the eighth thoracic vertebra, the average coronal curve measurement was 55.2 degrees, and the average apical rotation was 17.3 degrees. The average distance from the aortic wall to the vertebral body cortex at the apex of the curve was greater in the patients with scoliosis (4.0 mm) than at similar levels in the normal group (2.5 mm) (p < 0.05). The distance from the posterior aspect of the aorta to the anterior aspect of the spinal canal was less in the scoliosis group (11.1 mm) than in the normal group (19.2 mm) for the fifth to the twelfth thoracic level (p < 0.05). The aorta was positioned more laterally and posteriorly adjacent to the vertebral body at the fifth to the twelfth thoracic level in patients with scoliosis compared with that in normal patients as reflected in a smaller aorta-vertebral angle (p < 0.05). With an increasing coronal Cobb angle in the thoracic curve and apical vertebral rotation, the aorta was positioned more laterally and posteriorly (p < 0.05).nnnCONCLUSIONnIn patients with right thoracic idiopathic scoliosis, the aorta is positioned more laterally and posteriorly relative to the vertebral body compared with that in patients without spinal deformity.

Analysis of screw placement relative to the aorta and spinal canal following anterior instrumentation for thoracic idiopathic scoliosis

Study Design. Axial computed tomographic (CT) evaluation of the position of anterior vertebral body screws placed thoracoscopically in patients with adolescent idiopathic scoliosis (AIS). Objective. To evaluate the position of the anterior vertebral body screws relative to the spinal canal and the thoracic aorta following anterior spinal fusion and instrumentation for AIS. Summary of Background Data. Thoracoscopic anterior instrumentation and fusion is gaining more widespread use in the treatment of idiopathic scoliosis. However, the accuracy in the positioning of instrumentation has not been previously studied for this technically difficult surgery. Methods. CT examinations were performed following thoracoscopic anterior spinal fusion and instrumentation in 14 patients with right thoracic AIS. The vertebral body width (transverse dimension) and depth (anterior-posterior dimension) was measured for each thoracic vertebra. At each instrumented level, the position of the screw was analyzed to determine its proximity to the spinal canal and the aorta. The distance from the anterior cortex of the spinal canal to the posterior edge of the screw was measured. The position of each screw relative to the aorta was determined: D, the screw tip was distant to the aorta; A, the screw tip was adjacent to the aorta; C, the screw tip was felt to be against the aorta and creating some contour deformity on the outer wall of the aorta. Results. All 14 patients were female and had a single right thoracic curve. The average age of the patients was 13.3 years (range 12.4–15.1 years). The average preoperative coronal Cobb measurement was 55.9° (bending 26.4°) with correction to 8.9° at 2 years after surgery. The average number of levels fused was 6.6 (range 5–8) and a total of 106 screws were used (average 7.6/patient). The width of the vertebral bodies increased from T4 (24.0 mm) to T12 (33.6 mm), increasing an average of 1.2 mm per level, while the depth increased from 17.7 mm at T4 to 25.5 mm at T12. The average distance from the posterior aspect of the screw to the spinal canal was 5.3 mm (range−1.2 to 11.4 mm). There were no neurologic deficits in any patient. When analyzing the position of the screw tip relative to the aorta, 78 (73.6%) screws were distant from the aorta, 15 (14.2%) were adjacent to the aorta, and there were 13 (12.3%) screws that were thought to create a contour deformity of the aorta. There were no vascular complications at 2 years after surgery. Conclusions. Thoracoscopic instrumentation and fusion is technically demanding and relies on adequate visualization for accurate screw placement. The vertebral body width and depth are consistent between patients, with the vertebral body width increasing approximately 1.2 mm when progressing down the thoracic spine. Safe screw placement was achieved with adequate distance from the spinal canal; however, close screw proximity to the aorta was seen. The aorta was positioned on the left lateral aspect of the vertebral body in these patients, making anterior screw placement challenging in right thoracic AIS.

Restoration of Thoracic Kyphosis After Operative Treatment of Adolescent Idiopathic Scoliosis: A Multicenter Comparison of Three Surgical Approaches

Study Design. Multicenter analysis of 3 groups of patients who underwent surgical treatment for adolescent idiopathic scoliosis (AIS). Objective. To evaluate 3 surgical approaches to determine the modality that has the greatest influence on improving thoracic kyphosis. Summary of Background Data. AIS is characterized by thoracic hypokyphosis which may be restored to normal to varying degrees with surgery. Methods. A multicenter retrospective AIS surgical database was reviewed. Patients with only a structural main thoracic curve (Lenke 1, 2, or 3), and instrumentation of only the main thoracic curve were included. Lateral radiographs were analyzed to determine sagittal plane measurements before surgery, after surgery at 6 to 8 weeks, 1 year, and 2 years. The 3 groups were compared and statistical significance was defined as P < 0.05. Results. Three groups were analyzed: (1) ASF group (n = 135), Anterior spinal fusion and instrumentation, (2) PSF-Hybrid group (n = 86), PSF with proximal hooks, ± apical wires and distal pedicle screws, and 3) PSF-Hooks group (n = 132), PSF with only hooks. All groups had similar preoperative coronal main thoracic curve magnitudes (ASF: 50.6°, PSF-Hybrid: 49.1°, PSF-Hooks: 52.0°) and thoracic kyphosis (ASF: 23.7°, PSF-Hybrid: 19.3°, PSF-Hooks: 21.9°). After surgery, the T5–T12 kyphosis was greater in the ASF group (25.1°) compared with PSF-Hooks (19.0°) and PSF-Hybrid (18.5° (P < 0.05). At 1 year, thoracic kyphosis (T5–T12) remained greater in the ASF group (28.8°) compared with PSF-Hooks (22.6°) and PSF-Hybrid (20.2°) (P < 0.05), and was also greater at 2 years (29.9° vs. 23.8.8° and 19.7°) (P < 0.05). Kyphosis at the thoracolumbar junction was not seen in the PSF-Hybrid group. Lumbar lordosis increased only in the ASF group in response to the increase in thoracic kyphosis. Conclusion. ASFI is the best method to restore thoracic kyphosis when compared with posterior approaches using only hooks or a hybrid construct in the treatment of thoracic adolescent idiopathic scoliosis.

Complications associated with the Bernese periacetabular osteotomy for hip dysplasia in adolescents

BACKGROUNDnThe Bernese (Ganz) periacetabular osteotomy is an effective surgical procedure to reorient the acetabulum, allowing restoration of anatomic femoral head coverage and medial translation of the hip in adults with hip dysplasia. However, it is a challenging surgical procedure, and we know of no study that has specifically analyzed the complications and associated factors seen with this procedure in adolescent patients.nnnMETHODSnA retrospective clinical and radiographic review of a consecutive series of adolescent patients who underwent a Bernese periacetabular osteotomy for hip dysplasia was conducted.nnnRESULTSnEighty-three osteotomies were performed in seventy-six patients with an average age (and standard deviation) of 15.6 +/- 2.4 years. Significant improvement from the preoperative to the two-year follow-up evaluation was seen radiographically with regard to the lateral center-edge angle (-0.14 degrees to 35.5 degrees), the ventral center-edge angle (-5.13 degrees to 31.3 degrees), and the femoral head extrusion index (38.4% to 7.7%) (p < 0.0001 for all). There were three major complications, including excessive arterial bleeding requiring embolization in a patient with a prior acetabuloplasty, osteonecrosis of the acetabular fragment in a patient with severe dysplasia and subluxation of the hip, and osteonecrosis of the femoral head following combined periacetabular and femoral osteotomies in a patient with Charcot-Marie-Tooth disease. Eighteen hips (22%) had minor complications, including nonunion of the superior pubic ramus osteotomy (five hips), a superficial stitch abscess (four), and transient lateral femoral cutaneous nerve palsy (four). Nine hips (11%) underwent removal of symptomatic screws, and two required a second operation to reposition the acetabular fragment. An underlying diagnosis other than developmental dysplasia increased the prevalence of minor complications (p = 0.0017), while a major complication was more likely with longer surgery time, greater blood loss, and proximal femoral osteotomy.nnnCONCLUSIONSnThe Bernese periacetabular osteotomy is a joint-preserving procedure that very effectively corrects acetabular dysplasia in adolescent patients, providing improved radiographic results and a low rate of complications. Although the rate of minor complications is increased when there is an underlying diagnosis other than developmental dysplasia, no other predictors were identified. However, a major complication is more likely with a longer duration of surgery and with a concomitant femoral varus osteotomy.

Thoracoscopic scoliosis surgery affects pulmonary function less than thoracotomy at 2 years postsurgery.

Study Design. Prospective evaluation of pulmonary function before and 2 years after surgery following anterior scoliosis instrumentation. Objectives. To determine if thoracoscopic anterior scoliosis correction with instrumentation affected pulmonary function less than open thoracotomy approaches at 2 years follow-up. Summary of Background Data. The thoracoscopic approach has been shown to have a smaller reduction in pulmonary function tests (PFTs) compared with an open thoracotomy approach following anterior thoracic instrumentation for adolescent idiopathic scoliosis in the immediate postoperative period; however, it is unclear if a difference remains 2 years following the procedure. Methods. A total of 107 patients in a multicenter adolescent idiopathic scoliosis database underwent an anterior instrumented fusion for thoracic scoliosis. PFTs assessing forced vital capacity (FVC), forced expiratory volume (FEV1), and total lung capacity (TLC) were obtained prospectively before and 2 years after surgery. The patients were grouped as follows: Group I, thoracoscopic instrumented fusion (n = 36); Group II, open (thoracotomy) instrumented fusion without thoracoplasty (n = 28); and Group III, open instrumented fusion with thoracoplasty (n = 43). Results. Thoracoscopic instrumentation affected pulmonary function 2 years after surgery minimally, and on an average showed improvements in all parameters except the percent-predicted FVC, which decreased by 1% ± 11%, and percent predicted FEV, which decreased by 2% ± 9%. Improvements were noted in absolute FVC, FEV1, TLC, and percent-predicted TLC. This is in contrast to the patients treated with a thoracotomy, who had a greater persistent reduction in PFTs at follow-up. An added thoracoplasty to the thoracotomy approach, however, resulted in even greater residual reduction in PFTs at follow-up, with declines in percent-predicted FVC of 15%, percent-predicted FEV1 of 14%, and percent-predicted TLC of 8%. Conclusions. This study shows a clear advantage to the minimally invasive thoracoscopic approach with regards to pulmonary function when compared with the open thoracotomy approaches.

Thoracoscopic Anterior Instrumentation and Fusion for Idiopathic Scoliosis

Abstract Thoracoscopically assisted surgery is a new approach to access the anterior spine to perform biopsies, anterior releases, diskectomies, and anterior instrumentation and fusion for idiopathic thoracic scoliosis. This approach compromises the chest wall less than an open thoracotomy does because it uses several small portal incisions. It has been suggested that this approach allows fusion of fewer motion segments and better correction of curvature than does posterior spinal fusion and instrumentation. The technique, which is still evolving, is technically demanding, requiring advanced training and special instrumentation and anesthesia techniques.

Postoperative Ketorolac Does Not Predispose to Pseudoarthrosis Following Posterior Spinal Fusion and Instrumentation for Adolescent Idiopathic Scoliosis

Study Design. A retrospective review comparing patients who had postoperative ketorolac and those who did not following posterior spinal fusion and instrumentation (PSFI) for adolescent idiopathic scoliosis (AIS). Objective. To analyze the effect of postoperative ketorolac on the incidence of pseudoarthrosis in postoperative AIS patients. Summary of Background Data. Ketorolac (Toradol, Roche Laboratories, Nutley, NJ) is a nonsteroidal antiinflammatory drug that is an effective adjunct to manage postoperative pain. It has been previously demonstrated to inhibit spinal fusion in adult patients undergoing a L4 to sacral fusion. To our knowledge, there are no large studies analyzing this effect following PSFI for AIS. Methods. An IRB-approved retrospective medical record review was performed from 1994 to 2000 of patients undergoing a PSFI for AIS at a single institution. Segmental spinal instrumentation (Texas Scottish Rite Hospital) and iliac crest bone graft were used in both groups. Demographic and operative data were recorded. Patients were divided into those who had postoperative ketorolac (K group) and those who did not (NK group). Patients who had a surgically confirmed pseudoarthrosis were identified and the K group and NK group were statistically compared. Results. There were 161 patients in the NK group and 158 in the K group. There were no differences with respect to age (14.4 vs. 14.2 years), gender (83.9% vs. 84.8% females), levels fused (9.8 vs. 9.7), or preoperative curve magnitude (57.9° vs. 58.9°). In the K group, the number of doses of ketorolac administered was 6.7 for an average of 26.7 mg for a duration of 46 hours after surgery. Patients in the K group were more likely to have Motrin (average 5.8 doses) compared with the NK group (average 0.7 doses) (P < 0.01). No patient in the K group had a history of cigarette smoking compared with 2 patients in the NK group, both of whom went on to solid arthrodesis. The overall incidence of pseudoarthrosis was 2.5% for all patients. There was no difference in the incidence of pseudoarthrosis comparing the K (1.9%) and the NK group (3.1%)(P = 0.7). When the single rod posterior implants were excluded, there was no difference between the K (0.7%) and NK groups (1.8%) (P = 0.58). Conclusion. Ketorolac does not increase the incidence of developing a pseudoarthrosis when used as an adjunct for postoperative analgesia following a PSFI for AIS using segmental spinal instrumentation and iliac crest bone graft. The differences seen here compared with adults may be due to the greater healing potential in these young patients. We recommend utilization of ketorolac after surgery to supplement pain management when necessary.