Jeff Pawelek

Preservation of thoracic kyphosis is critical to maintain lumbar lordosis in the surgical treatment of adolescent idiopathic scoliosis.

Study Design. Retrospective analysis of prospectively collected multicenter series. Objective. To evaluate the sagittal profile of surgically treated adolescent idiopathic scoliosis (AIS) patients. Summary of Background Data. With the increasing popularity of segmental pedicle screw spinal instrumentation, thoracic kyphosis (TK) is often sacrificed to achieve coronal and axial plane correction. Methods. Radiographs of AIS patients with a Lenke type 1 deformity and minimum 2-year follow-up after selective thoracic fusion (lowest instrumented vertebra of T11, T12, or L1) were evaluated. Changes in TK were correlated with changes in lumbar lordosis (LL). Patients were divided according to approach (open/thoracoscopic anterior vs. posterior). Analysis of variance was used to compare pre and postoperative radiographic measures. Results. Two hundred fifty-one patients (age: 14 ± 2 years) were included. Sixty seven percentages of the patients had anterior surgery (97 open anterior, 71 thoracoscopic) and 33% (83 patients) had posterior spinal fusion. A decrease in postoperative TK was significantly correlated (P ≤ 0.001) with a decrease in LL at first erect (r = 0.3), 1 year (r = 0.4) and 2 years (r = 0.4), independent of surgical approach. LL decreased significantly at the first erect regardless of approach (P = 0.003); however, at 2-year postoperative TK and LL were significantly decreased after a posterior approach (P ≤ 0.001) when compared with an anterior approach that added kyphosis. The decrease in LL (5.6° ± 9.7°) was nearly twice the decrease in TK (2.8° ± 11.4°) in the posterior group at 2-years. Conclusion. Given that thoracic AIS is often associated with a preexisting reduction in TK, ideal surgical correction should address this deformity. Procedures which further reduce TK also reduce LL. It is unclear if the loss of LL from thoracic scoliosis correction will compound the loss of LL that occurs with age and lead to further decline in sagittal balance. With this concern, we recommend a posterior column lengthening and/or an anterior column shortening to achieve restoration of normal TK and maximal LL.

Perioperative complications after surgical correction in neuromuscular scoliosis.

Purpose To evaluate the perioperative complications associated with surgical correction in neuromuscular scoliosis and to identify the risk factors associated with these complications. Methods A retrospective review of the hospital charts of patients with neuromuscular scoliosis who underwent surgical correction at a medical center was performed. Results Data was available on a total of 175 patients. The overall perioperative complication rate was 33.1% (96 complications in 58 patients). Complications were subdivided into pulmonary issues (19.4%), wound and implant infections (9.7%), cardiovascular complications (4.0%), intraoperative neurological changes (4.6%), miscellaneous complications (5.7%), and problematic instrumentation (3.4%). No patient had an identifiable permanent postoperative change in neurological status. The complication rate in patients who underwent single-stage procedures (37.4%) was found lower than that in patients who underwent staged procedures (57.1%). There were no deaths during the perioperative period. Conclusions Patients with neuromuscular scoliosis are at high risk of developing perioperative complications after surgical correction of their deformity (overall rate, 33.1%).

Prospective evaluation of 50 consecutive scoliosis patients surgically treated with thoracoscopic anterior instrumentation.

Study Design. Prospective, consecutive, single-surgeon case series of patients treated for scoliosis with thoracoscopic anterior spinal instrumentation. Background. A thoracoscopic approach for insertion of anterior instrumentation has been developed in the past 10 years, which obviates many of the disadvantages of the open anterior thoracic approach. The morbidity associated with a thoracoscopy is limited because of the minimal skin and chest wall dissection required with this method. Purpose. The purpose of this evaluation is to report a single surgeon’s experience with an initial series of 50 patients. The goal is to report the outcomes with regards to the radiographic findings, pulmonary function, and the SRS Outcomes Instrument, as well as a review of the perioperative data and complications. Methods. The primary author’s initial 50 thoracoscopic anterior spinal instrumentation patients were consecutively collected. Data collection included demographics, such as age, gender, and diagnosis. Data regarding the surgical procedure included the operative time, intraoperative estimated blood loss, as well as the number of levels instrumented anteriorly. In the perioperative hospital period, data were collected with regard to the length of the hospital stay, the number of days in the ICU, the number of days of ventilator support, and the number of days after surgery when conversion from IV to PO pain medication occurred. Radiographic data were obtained systematically on each patient and measured by authors other than the surgeon. The SRS 22 and/or 24 Outcomes Questionnaire and pulmonary function tests were administered to patients at similar intervals. Results. The series consisted of 44 females and 6 males with a mean age of 14 years (range, 9–48 years). Forty-five of the 50 patients were available for clinical and radiographic evaluation at greater than or equal to 2 years after surgery. The average length of follow-up for these 45 patients was 33 months (range, 2–5 years). The mean operative time for the procedure was 350 ± 50 minutes and ranged from 265 to 528 minutes. The estimated intraoperative blood loss averaged 431 ± 273 mL (range, 75–1,400 mL). Normalizing the operative time and estimated blood loss based on the number of levels treated resulted in an average operative time per level of 48 ± 6 minutes per level and an estimated intraoperative blood loss per level of 60 ± 37 mL per level. The preoperative thoracic Cobb averaged 53° ± 9° (range, 40°–80°). At most recent follow-up (≥2 years), the thoracic Cobb averaged 24° ± 7°. Implant failure occurred in 3 cases. Conclusion. Thoracoscopic anterior instrumentation for adolescent idiopathic scoliosis is a viable surgical option. The outcomes of this consecutive series of patients is comparable to prior open and endoscopic series presented in the literature. The technical challenges of this operation are evident in the learning curve effect, which has been demonstrated.

Analysis of sagittal alignment in thoracic and thoracolumbar curves in adolescent idiopathic scoliosis: how do these two curve types differ?

Study Design. Retrospective chart review and radiographic analysis. Objective. To determine if differences exist in the sagittal alignment of adolescent idiopathic scoliosis (AIS) patients with thoracic versus thoracolumbar curve patterns. Summary of Background Data. Relative anterior overgrowth has been suggested as the possible pathomechanism behind thoracic scoliosis. Given the proposed importance of the sagittal alignment on the development of AIS and the known association between pelvic parameters and sagittal alignment, the authors postulate that pelvic incidence may influence the location of vertebral column collapse associated with different AIS curve types. Methods. A multicenter surgical database was used to compare preoperative radiographic measurements between patients with primary thoracic curves (Lenke 1A, B), primary thoracolumbar curves (Lenke 5), and normal adolescents. Results. Pelvic incidence was significantly greater in both groups of AIS patients compared with normal adolescents. Patients in the primary thoracic curve group were found to have a significantly increased sacral slope and a decreased thoracic kyphosis relative to the control group. Patients in the primary thoracolumbar curve group had a significantly increased pelvic tilt; however, a relatively normal thoracic kyphosis, lumbar lordosis, and sacral slope compared with the respective control values. Conclusion. An increased pelvic incidence, associated with both thoracic and thoracolumbar curves when compared with the normal adolescent population, does not appear to be the potential determinant of the development of thoracic versus thoracolumbar scoliosis, but may be a risk factor for the development of adolescent idiopathic scoliosis. The theory of anterior overgrowth may be supported by the identification of thoracic hypokyphosis, despite an increased pelvic incidence and lumbar lordosis, in patients with thoracic scoliosis. The association between sagittal measurements and the etiology of thoracolumbar curve formation is less clear; however, regional anterior overgrowth in the lumbar spine may also be responsible for the deformity.

Innovation in growing rod technique: a study of safety and efficacy of a magnetically controlled growing rod in a porcine model.

Study Design. Prospective in vivo randomized study. Objective. To evaluate the safety and efficacy of a distraction-based magnetically controlled growing rod (MCGR) in a porcine model. Summary of Background Data. A high number of complications related to frequent surgical rod lengthenings has been a generally accepted outcome in growing rod surgery for early-onset scoliosis. A potentially safer technique is a system that does not require repetitive surgery. Methods. Seven-month-old pigs were randomly assigned to an experiment group (EG; n = 6) and a sham group (SG; n = 3). One animal in the EG became paralyzed because of a misplaced pedicle screw and was killed per the study protocol. Therefore, a total of 8 animals completed the study. The EG underwent weekly spine distraction using the MCGR. Spinal height was assessed by vertebral unit height measurements on weekly lateral radiographs. Results. A total of 49 mm of distraction across the unfused vertebral levels was planned during a 7-week period (7 mm per wk). Radiographical analysis of the MCGR device revealed an average distraction of 39 mm (range, 32–46 mm), resulting in achievement of 80% of predicted spinal height. Prior to removal of implants, spinal height for the EG was similar to the SG. However, accelerated increase in vertebral unit height was noted in the EG during the 3-week period after implant removal, which resulted in significantly greater overall spinal height in the EG (32.2% vs. 11.7%, P ⩽ 0.05). No MCGR-related complications occurred. Conclusion. The MCGR provided 80% of predicted spinal height by noninvasive remote distraction in this animal model. The accelerated increase in spinal height of the experimental animals after implant removal was an unexpected finding which requires additional research to better understand the effect of distraction on spinal growth. This study establishes a foundation for future research in an attempt to use a less invasive technique in distraction-based correction of early-onset scoliosis.

Anterior column realignment (ACR) for focal kyphotic spinal deformity using a lateral transpsoas approach and ALL release.

Study Design: Retrospective case series. Objectives: Introduce and evaluate the safety of a new technique of anterior column realignment (ACR) using a lateral transpsoas approach with release of anterior longitudinal ligament and annulus for correction of focal kyphotic deformity. Summary of Background Data: Spinal sagittal imbalance can adversely affect the long-term outcomes of patients with spinal deformity. Methods: Clinical and radiographic review of patients who underwent ACR. Results: Seventeen consecutive patients (12 females; 5 males) with a mean age of 63 years (range, 35–76 y) and a mean follow-up of 24 months (range, 12–82 mo) were identified. Fourteen of 17 (82%) had previous spine surgery and 12/17 (71%) had previous fusion. Twelve of the 17 (71%) underwent ACR for adjacent segment disease. Fifteen patients (88%) had Smith-Petersen osteotomies at the ACR level. The mean motion segment angle was 9 degrees preoperatively, which corrected to −19 degrees after ACR and to −26 degrees after posterior instrumentation. Motion segment angle was maintained at −23 degrees at the latest follow-up. The mean lumbar lordosis was −16 degrees preoperatively, which improved to −38 degrees after ACR and to −45 degrees after posterior instrumentation. Lumbar lordosis was maintained at −51 degrees at the latest follow-up. Pelvic tilt averaged 34 degrees before ACR and improved to 24 degrees after ACR and posterior instrumentation and maintained at 25 degrees at the latest follow-up. Patients with preoperative negative T1 spinopelvic inclination (T1SPI) corrected from −6 to −2 degrees and those with 0 or positive T1SPI corrected from 5 to −3 degrees after ACR at the latest follow-up. Eight patients (47%) had 10 complications. Four complications occurred after ACR. Two of 4 were neurological (1 persistent weakness) and 1 was vascular injury during anterior plate removal. Conclusion: Compared with posterior-based techniques, our preliminary results of ACR showed similar correction capacity and similar rate of morbidities for the treatment of focal kyphotic spinal deformity. Careful case selection, attention to the details of the technique, and enough experience are prudent elements for a desirable outcome.

Spontaneous lumbar curve correction in selective thoracic fusions of idiopathic scoliosis: a comparison of anterior and posterior approaches.

Study Design. A retrospective evaluation of adolescent idiopathic scoliosis (AIS) patients treated with selective thoracic instrumentation and fusion. Objective. To evaluate the predictors and the effect of surgical approach (anterior versus posterior) on spontaneous lumbar curve correction (SLCC) after selective thoracic fusion in patients with structural thoracic and compensatory lumbar curves. Summary of Background Data. Spontaneous coronal correction of the unfused lumbar curve has been described previously; however controversy continues regarding the effect of surgical approach on SLCC. Methods. One hundred thirty-two anterior and 44 posterior selective thoracic fusions instrumented distally to T11, T12, or L1 were identified from a multicenter AIS database. A 2-way ANOVA was used to compare SLCC with regards to surgical approach and the lowest instrumented vertebra (LIV). A Pearsons correlation analysis was utilized to identify radiographic variables associated with SLCC. A secondary analysis of surgical approach was then performed on 28 pairs of patients matching the factors that correlated positively with SLCC. Results. The average SLCC for the anterior approach (44% ± 19%) was less than that for the posterior approach (49% ± 19%; P = 0.07), and was found to increase significantly with a more distal LIV (P = 0.03). Pearsons correlation analysis revealed the strongest correlations between SLCC and preoperative lumbar curve flexibility (r = 0.20) and 2-year postoperative thoracic curve percent correction (r = 0.47). A secondary analysis of SLCC in paired curves matched by LIV, lumbar curve flexibility and thoracic percent correction revealed no difference between anterior (48%) and posterior (49%) approaches (P = 0.75). Conclusion. Anterior and posterior instrumented fusions performed selectively on the appropriate curves result in equal SLCC when matched by LIV, flexibility of the lumbar curve, and percent thoracic curve correction achieved. This suggests that the observed phenomenon of SLCC after selective thoracic fusion in AIS is independent of surgical approach and can be reliably achieved with either technique.

Three-dimensional analysis of thoracic apical sagittal alignment in adolescent idiopathic scoliosis.

Study Design. Retrospective review of a series of adolescent idiopathic scoliosis patients. Objective. To perform a 3-dimensional (3D) analysis of patients with thoracic scoliosis to identify differences in the thoracic sagittal alignment measured from the standard lateral projection as compared to the “true lateral” view. Summary of Background Data. It has been difficult to clinically obtain radiographs in the planes of maximum spinal deformity. Recently, 3D models of the spine have been developed using biplanar radiographic reconstructions that allow a more accurate assessment of spinal alignment. Methods. Three-dimensional spinal reconstructions using biplanar radiographs were used to evaluate the apical thoracic sagittal profile. A measurement of sagittal curvature from 2 vertebral levels above and below the thoracic apex (5 vertebrae) was recorded from the standard lateral view. The 3D reconstructions were then rotated to achieve a “true lateral” view of the apical thoracic vertebra and the sagittal apical curvature was remeasured. The difference in the 2 measures of sagittal thoracic apical alignment was compared using repeated measures ANOVA, and then correlated to the coronal thoracic Cobb magnitude using a Pearson correlation analysis (P < 0.05). Results. Sixty-six adolescent idiopathic scoliosis patients with right thoracic scoliosis (Cobb averaged 47° ± 10°) were evaluated. The apical thoracic sagittal curvature in the standard lateral view averaged 11° ± 10° of kyphosis (range: −8° to 38°). This was statistically greater (P < 0.001) than the apical sagittal curvature in the “true lateral” view that averaged 1° ± 9° (range:−23° to 22°). The standard lateral view was rotated an average of 13° ± 4° to achieve the ideal lateral view of the thoracic apex. Conclusion. This 3D analysis of thoracic scoliosis demonstrated a consistent loss of kyphosis within the 5 thoracic apical vertebrae. The true apical sagittal profile was found to be overestimated by an average of 10° as compared to the perceived alignment from standard lateral radiographs.

How Does Thoracic Kyphosis Affect Patient Outcomes in Growing Rod Surgery

Study Design. Retrospective review of a multicenter series. Objective. This study was conducted to specifically identify the complication rate of growing rod surgery in patients with normal (10°–40°) versus abnormal thoracic kyphosis. Summary of Background Data. Surgical treatment options for progressive early onset scoliosis include spinal fusion versus growth-sparing techniques. The current most commonly employed growing rod technique involves short fusions at the foundation sites using either hooks or screws as anchors and placement of dual growing rods spanning the deformity. Although the coronal deformity in these patients has been studied extensively, the sagittal profile has received less attention as a possible factor in complication rates and patient outcomes. Methods. Out of 387 patients who underwent surgical placement of growing rods, 90 patients had complete clinical and radiographical data, with 2-year follow-up after initial surgery. Patients were categorized into 3 groups on the basis of preoperative thoracic kyphosis magnitude: less than 10° (K– group), 10°–40° (N group), and more than 40° (K+ group). Patient diagnosis, demographics, surgical information, radiographical measurements, and complication types were tabulated and analyzed. A P value of <0.05 was considered significant for all statistical tests. Results. The K– group experienced 27 total complications including 15 general medical complications, the N group had 20 total and 4 general complications, and the K+ group had 55 total and 22 general complications. Patients in the K+ group were 3.1 times more likely to experience a complication than those in the N group, which was statistically significant (P < 0.05). When considering all types of complications, length of follow-up, T2–T5 proximal kyphosis, postoperative Cobb angle, and rod diameter were identified as confounding variables. When the confounding variables were taken into consideration in the analysis, the odds ratios were no longer significant between the N and K+ groups. Patients in the K+ group and K– group were 2.95 and 2.89 times more likely to experience a general medical complication than those in the N group, respectively (P > 0.05). The rate of implant-related complications between the groups did not reach statistical significance, although the K+ group had the most implant complications (n = 34), including 25 rod breakages in 16 patients. Syndromic patients had 2.9 times the risk of having an overall complication when compared with the entire patient series (P < 0.05). The number of patients who experienced multiple complications was higher in the K– and K+ groups than in the N group. Conclusion. Patients with thoracic hyperkyphosis present even more of a challenge with respect to complications, specifically implant-related complications. Our study shows that growing rod surgery in patients with kyphosis more than 40° has significantly more general and implant complications than that in patients with normal thoracic kyphosis. Implant complications were more common in hyperkyphotic (>40°) patients and increased linearly with increasing kyphosis. The most common implant complication was rod breakage. Patients with hyperkyphotic thoracic spines, particularly syndromic patients, must be monitored closely and parents should be counseled regarding the likelihood of future adverse events.

Surgical treatment of main thoracic scoliosis with thoracoscopic anterior instrumentation. a five-year follow-up study.

BACKGROUND The surgical outcomes in patients with scoliosis at two years following anterior thoracoscopic spinal instrumentation and fusion have been reported. The purpose of this study was to evaluate the results at five years. METHODS A consecutive series of forty-one patients with major thoracic scoliosis treated with anterior thoracoscopic spinal instrumentation was evaluated at regular intervals. Prospectively collected data included patient demographics, radiographic measurements, clinical deformity measures, pulmonary function, an assessment of intervertebral fusion, and the scores on the Scoliosis Research Society (SRS-24) outcomes instrument. Perioperative and postoperative complications were recorded. Patient data for the preoperative, two-year, and five-year postoperative time points were compared. In addition, a univariate analysis compared selected two-year radiographic, pulmonary function, and SRS-24 data of the study cohort and those of the patients lost to follow-up. RESULTS Twenty-five (61%) of the original forty-one patients had five-year follow-up data and were included in the analysis. Between the two-year and five-year follow-up visits, no significant changes were observed with regard to the average percent correction of the major Cobb angle (56% +/- 11% and 52% +/- 14%, respectively), average total lung capacity as a percent of the predicted value (95% +/- 14% and 91% +/- 10%), and the average total SRS-24 score (4.2 +/- 0.4 and 4.1 +/- 0.7). Radiographic evaluation of intervertebral fusion at five years revealed convincing evidence of a fusion with remodeling and trabeculae present at 151 (97%) of the 155 instrumented motion segments. No postoperative infections or clinically relevant neurovascular complications were observed. Rod failure occurred in three patients, and three patients required a surgical revision with posterior spinal instrumentation and fusion. CONCLUSIONS Thoracoscopic anterior instrumentation for main thoracic idiopathic scoliosis results in five-year outcomes comparable with those reported previously for open anterior and posterior techniques. The radiographic findings, pulmonary function, and clinical measures remain stable between the two and five-year follow-up time points. Thoracoscopic instrumentation provides a viable alternative to treat spinal deformity; however, the risks of pseudarthrosis, hardware failure, and surgical revision should be considered along with the advantages of limited muscular dissection and improved scar appearance. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.