An early experience of lumbopelvic fixation techniques at Alexandria University

Abstract

Background The aim of lumbopelvic fixation is to obtain a solid fusion across the lumbosacral junction. There are many indications for lumbopelvic fixation, namely, spinal deformity in cases requiring long segment fusion, pelvic obliquity, pseudarthrosis at the lumbosacral junction, infection or osteolytic tumors, and pathologic fractures. The classical iliac screws should be contained within the iliac bone but have some disadvantages: excessive soft tissue dissection needed for accurate insertion, screw prominence with patient discomfort, and usually, a side connector is needed to connect the iliac screws to the rest of the construct. Lumbopelvic fixation by insertion of S2 alar-iliac (S2AI) screws was recently described to overcome these disadvantages. In this study, the authors present the initial results for the evaluation of lumbopelvic fixation through the insertion of S2AI screws in 19 consecutive patients operated in the neurosurgery department at Alexandria University. Objective The aim of the study was to evaluate the efficacy and complications of lumbopelvic fixation through the use of S2 alar-iliac screws. Methods The authors conducted a retrospective cohort study of data collected from the database of patients who underwent lumbopelvic fixation through the insertion of S2AI screws from 2016 to 2019 at a single institution. Results There were 19 patients indicated for lumbopelvic fixation, operated by modern instrumentation systems using lumbar pedicle screws and S2 alar-iliac screws. There were 14 females and 5 males. The mean age at the time of the operation was 38.6 ± 19.4 years with a range from 11 to 65 years. There was a total of 37 S2AI screws, screw diameter was 7mm in all cases regardless of age, and the length of the screws ranged from 50 mm in a young female patient (11 years) to 90 mm in an old male patient (60 years). Two screws were inserted per patient except in one case with congenital scoliosis due to the bad bone quality and the multiple iatrogenic wrong paths. Postoperative VAS score for back pain was greatly improved in all patients after the first 6 months of follow-up from 8 ± 1.5 to 3.5 ± 1.2 (paired t-test = 11.182, P<0.001). All patients had a good spinal range of motion to maintain normal daily activities without any significant restrictions after the first 3 months of follow-up. Immediate postoperative radiological follow-up had revealed 2 cases of posterior pelvic breaches and one case with anterior pelvic breach but without clinical manifestations with no need for revision. Two cases of unilateral screw breakout were observed after the first 6 months of follow-up. Removal of screws after the first 6 months was done in one patient with spondylodiscitis due to the unresolved infection and screw pullout. Conclusion The insertion of S2AI screws is an effective technique for lumbopelvic fixation with a relatively low rate of complications. Pelvic breaches are the commonest complications encountered during the insertion of S2AI screws, although no significant clinical morbidities were reported.

Sacropelvic fixation

“…Unlike iliac screws, this technique avoids the implant prominence and obviates the need for connectors [51,52]. This technique has the lowest overall complication rate among other techniques, but long-term follow-up is required, particularly to evaluate its adverse effects on the SI joint [1,53,54] (Fig. 16).…”

New classification of S1 pedicle morphometry impacting pedicle screw insertion technique

“…Pedicle screw fixation of the S1 vertebra has been employed as a technique for stabilization of the lumbosacral spine as a management of degenerative disc diseases such as spondylolistheses, spinal deformities, traumatic or pathologic fractures, infections and malignancies (primaries as well as osteolytic metastases). [1][2][3][4][5][6] The conventional entry point for inserting the screw into the S1 pedicle has been reported to be 'below and lateral to the superior S1 facet'. 7 This technique was originally described by Carlson et al and Smith et al as a modification of Roy-Camill's technique which involved introducing converging screws medially.…”