Comparison of Total Body Irradiation-based Versus Chemotherapy-based Conditionings for Early Complications of Allogeneic Hematopoietic Stem Cell Transplantation in Children With ALL

BACKGROUND

Total body irradiation (TBI) is the cornerstone of conditioning regimens in pediatric hematopoietic stem cell transplantation for acute lymphoblastic leukemia. As the late effects and survival comparison between TBI and chemotherapy were well analyzed before, in this study, we aim to focus on the first 100 days and early complications of transplantation.

METHODS

This retrospective study involves 72 pediatric patients (0 to 18 y) underwent first hematopoietic stem cell transplantation for acute lymphoblastic leukemia between October 2015 and May 2019. Patients are divided into 2 groups regarding conditioning regimens. Conditionings includes either TBI 1200 cGy/6 fractions/3 days and etoposide phosphate or busulfan, fludarabine, and thiotepa. Busulfan was administered IV and according to body weight.

RESULTS

The incidences of acute graft versus host disease grade 2 to 4, veno-occlusive disease, capillary leakage syndrome, thrombotic microangiopathy, blood stream infection, hemorrhagic cystitis and posterior reversible encephalopathy syndrome before day 100 were similar for both conditioning regimens; however, patients received TBI-based conditioning had significantly longer neutrophil engraftment time (17.5 vs. 13 d, P=0.001) and tended to have more engraftment syndrome (ES) (45.5% for TBI vs. 24.0% for chemotherapy, P=0.069). Multivariate analysis showed that TBI-based conditioning was associated with a longer neutrophil engraftment time (hazard ratio [HR]=1.20, P=0.006), more cytomegalovirus (CMV) reactivation (HR=3.65, P=0.038) and more ES (HR=3.18, P=0.078).

CONCLUSIONS

Our findings support chemotherapy-based regimens with early neutrophil engraftment, less ES and CMV reactivation compared with TBI. Although there is no impact on survival rates, increased incidence of ES and CMV reactivation should be considered in TBI-based regimens.

Posterior Cervical Keyhole Laminoforaminotomy: A Cadaveric Comparative Study to Evaluate Limits of Bony Resection

BACKGROUND

The posterior cervical keyhole (KH) laminoforaminotomy has been described to involve the lateral portion of cervical laminae of the upper vertebra alone (small KH) or of both upper and lower vertebrae (large KH).

OBJECTIVE

To microscopically compare the two keyhole techniques in terms of their ability to expose the corresponding cervical roots.

METHODS

Ten cadaveric specimens were operated bilaterally from C3-4 to C6-7 level to expose a total of 80 nerve roots. The large KH was applied to the left side, the small KH to the right side. The maximal length of exposed nerve roots was measured under microscope. The virtual optimal KH surface area was determined using digital software. Each root was inspected for exposure of its root and axilla.

RESULTS

The maximal exposed nerve root length on the large KH side was significantly larger than on the small KH side at C3-4, C5-6, and C6-7 levels (P = .031, P = .002, P = .003). No significance was reported for C4-5 (P = .06). We could expose right axillae in (3/40) and left axillae in (33/40; P < .001). Optimal keyhole surface areas were 37.9, 38.2, 38.7, and 46.2 mm2 in craniocaudal order.

CONCLUSION

Large KH defects involving both upper and lower laminae and facets can expose the roots to greater extent than small KH defects at C3-4, C5-6, and C6-7 levels. Large KH defects may allow better exposure of nerve roots axillae than small KH defects.