Iliac screw instrumentation to the pelvis in children with neuromuscular and syndromic scoliosis. No lateral connectors and respect sagittal balance.

STUDY DESIGN: One-center retrospective cohort study. BACKGROUND: Compared to the traditional iliac screw technique, the modified iliac screw technique has a lower rate of distal implant failure in the treatment of neuromuscular scoliosis patients with pelvic obliquity. However, the reasons for decreased failure with the modified iliac screw technique are controversial. QUESTIONS/PURPOSES: (1) Is distal implant failure, as evident by implant breakage or disconnection, more likely to occur in patients receiving the traditional iliac screw technique (PSIS) compared to the modified S2AI (MODS2) technique? (2) After controlling for relevant confounding variables, are there other identifiable risk factors for distal implant failure? METHODS: We identified patients who underwent pelvic screw fixation by three pediatric spine surgeons from January 2007 to July 2017. Based on the starting point of the iliac screws, patients were divided into two groups. Group 1 consisted of PSIS fixation with an offset connector. Group 2 consisted of modified S2AI fixation without an offset connector. Demographic, operative, and radiographic data were obtained. RESULTS: Cobb angle, lumbar lordosis, and pelvic obliquity were not significantly different between the two groups. Overall distal implant failure was 40/100 (40%) and significant between Group 1 PSIS 29/53 (55%) and Group 2 MODS2 11/47 (23%) (p = 0.002). No other complications were significant. Three risk factors were identified with implant failure: high pelvic incidence (17-fold increase, 95% confidence interval [CI] = 5.5 to 53.1, p < 0.001), high angle rod contour (3.8-fold increase, 95% CI = 1.2 to 11.9, p = 0.023), and use of an offset connector (3.2-fold increase, 95% CI = 1.0 to 10.3, p = 0.049). Failure did not correlate with the use of a cross-link, iliac screw diameter, or screw density. Revision surgery related to distal implant failure did not significantly differ between the two groups. CONCLUSIONS: Compared to the use of an offset connector with PSIS fixation, MODS2 fixation had a lower rate of implant failure. Sagittal balance parameters, namely pelvic incidence and angle of rod bend, were the major risk factors for implant failure. LEVEL OF EVIDENCE: III.

Operative time in adolescent idiopathic scoliosis surgery: a need for a standard definition.

Our objective is to report and define 'operative time' in adolescent idiopathic scoliosis (AIS) posterior spinal fusion surgeries. Documenting key times during surgery are important to compare operative risks, assess learning curves, and evaluate team efficiency in AIS surgery. 'Operative time' in literature has not been standardized. Systematic review was performed by two reviewers. Keywords included operative time, duration of surgery, and scoliosis. One thousand nine hundred six studies were identified, 1092 duplicates were removed and 670 abstracts were excluded. Of the 144 articles, 67 met inclusion and exclusion criteria. Studies were evaluated for number of patients, operative time, and definition of operative time. Meta-analysis was not performed due to confounders. Of the 67 studies (6678 patients), only 14 (1565 patients) defined operative time, and all specified as incision to closure. From these 14 studies, the median operative time was 248 minutes (range 174-448 minutes). In the 53 studies (5113 patients) without a definition, one study reported time in a non-comparable format, therefore, data were analyzed for 52 studies (5078 patients) with a median operative time of 252 minutes (wider range 139-523 minutes). A clear standardized definition of operative or surgical time in spine surgery does not exist. We believe that operative time should be clearly described for each published study for accurate documentation and be defined from incision time to spine dressing completion time in order to standardize study results. Level of evidence: IV.

Hereditary spherocytosis: a risk factor for thigh pressure myonecrosis in posterior spine surgery.

The objective of this study was to make surgeons aware of a potential pressure complication in posterior spine surgery for patients with hereditary spherocytosis (HS) and to present a plausible hypothesis for injury. Posterior spine surgery is common practice for adolescent idiopathic scoliosis (AIS). Common, less severe surgical risks include pressure ulcers; while rare, more severe pressure complications include rhabdomyolysis and compartment syndrome. In patients with HS, a familial hemolytic disorder with altered red cell deformability, it is unknown if their red cell disorder is an additional risk factor for pressure-related surgical injuries. Two patients with HS, an 18-year-old male and a 17-year-old female, were both post-splenectomy and underwent revision posterior spinal fusion and instrumentation for progressive AIS. Surgery lasted 9 hours and 7 hours respectively, with no intraoperative complications other than prolonged surgical time due to revision nature of the deformities. Thigh redness and swelling was noted in both patients directly deep to the thigh pads. Thigh myonecrosis was diagnosed with eventual recovery in both cases. Patients with HS may be at inherent more risk of pressure complications during posterior spine surgery. We propose that thigh myonecrosis occurs with decreased perfusion and hemolysis from HS erythrocytes' inherent fragility, decreased deformability within capillaries, and prolonged microvasculature compression from positioning, causing poor microvascular perfusion, tissue ischemia, and reperfusion injury. Level of veidence: IV.

Primary Spinal Epidural/Extramedullary Ewing Sarcoma in Young Female Patients.

Primary spinal epidural/extramedullary ewing sarcoma (ES) is a rare extraosseous lesion. Extraosseous ES has a similar demographic as osseous ES, primarily affecting adolescents and young adults and male propensity. Reported 5-year survival is 0% to 37.5% for spinal extraosseous ES. METHODS: Two girls, 19 and 14 months old, presented with progressive lower extremity paraplegia and incontinence. Both had a compressive epidural/extramedullary mass without metastases and underwent decompression with multilevel laminectomy and tumor excision. Primary spinal epidural/extramedullary ES was diagnosed. RESULTS: Case 1 received 34 weeks of chemotherapy and radiation therapy, and case 2 received 14 cycles of chemotherapy and autologous stem cell rescue without radiation therapy. After more than 5- and 8-year follow-up, case 1 and case 2 are walking and disease-free, respectively. CONCLUSION: These cases are the youngest presentation reported for primary spinal epidural/extramedullary ES and suggest that toddlers have a better prognosis for survival than older children and adolescents.