Table 2.
Results of 12 studies assessing preoperative and/or postoperative fractional curve of adult degenerative scoliosis patients
| Study | Preoperative FC | Postoperative FC | FC correction | FC radiographic predictors | Conclusions |
|---|---|---|---|---|---|
| Zhang et al. [16] 2021 | 13.6° ± 8.2° | 5.9 ± 5.1° | p < 0.001 | Preoperative FC with L4 coronal tilt toward C7 plumbline is associated with postoperative coronal imbalance | Directionality of preoperative FC toward C7 plumbline increasing risk of postoperative coronal imbalance |
| Amara et al. [23] 2020 | 1 Level = 15.3° ± 8.2°, 2 levels = 117.9°, 3 levels = 16.3° | 13.6° ± 8.2° | Group 1 vs. 2 = 0.0062; group 1 vs. 3 = 0.017; group 2 vs. 3 = 0.99 | None | Additional interbody fusion levels at the FC resulted in more fractional curve correction, more major curve correction, increasing lordosis without increasing morbidity |
| Amara et al. [23] 2019 | FC = 15.7°, LT = 16.7°, UT = 16.9° | NR | NR | None | Treatment of only the FC was associated with lower complication rates, shorter hospital LOS and reduced blood loss than fusion to UT or LT levels; FC group had higher rates of re-extension UT or LT levels |
| Chou et al. [23] 2018 | FC > 10° Matched cohort: preop FC–cMIS: 18 and open: 18 | Unmatched cohort: postop FC – cMIS: 17 and open: 19.6 | cMIS = 6.9°; Open = 8.5° | None | cMIS achieved similar reduction in leg pain and correction of fractional curve as traditional open surgery, despite significantly fewer cMIS patients undergoing direct decompression |
| Brown et al. [17] 2004 | 21° | 10.6° | NR | Less postoperative FC decreased risk of L5–S1 degeneration | Patients with good postop FC achieved better outcomes with posterior fusion to L5, avoiding sacral fusion |
| Yagi et al. [21] 2014 | Hybrid = 23° ± 9°, control = 24° ± 10° | Hybrid = 7 ± 4°, control = 15 ± 8° | Percent correction of lumbosacral curve significantly better in hybrid versus control (p < 0.001) | None | Hybrid patients had improved curve correction, fewer levels fused, decreased blood loss and fewer revision procedure when compared to control |
| Manwaring et al. [24] 2014 | TLIF = 9.2°, control = NR | TLIF = 4.1°, control = NR | NA | None | Significant fractional curve correction in staged cMIS is achieved through 2 stage TLIF treatment of L5–S1 |
| Pugely et al. [18] 2017 | Group B = 19.4°; group F = 25.5°; group S = 17.7° | NA | NA | None | Sciatic nerve pain in setting of lumbar structural curves is associated with foraminal stenosis at the concavity of the caudal fractional curve; femoral nerve pain likely caused by stenosis at concavity of main structural curve (L3 or below) |
| Buell et al. [25] 2021 | All = 20.2° ± 7.0°, TLIF = 19.4° ± 7.2°, ALIF = 20.8° ± 6.9° | All = 6.9° ± 5.2°, TLIF = 7.1° ± 5.4°, ALIF = 6.8° ± 5.1° | Multiple regression demonstrated 1-mm increase in L4–5 TLIF cage height led to 2.2° reduction in L4 coronal tilt (p = 0.011), and 1° increase in L5–S1 ALIF cage lordosis led to 0.4° increase in L5–S1 segmental lordosis (p=0.045). Matched analysis demonstrated comparable fractional correction (TLIF = -13.6° ± 6.7° vs. ALIF = -13.6° ± 8.1°, p = 0.982). | None | Results demonstrate comparable fractional curve correction (66.7% for TLIF patients versus 64.8% for ALIF patients), despite the use of significantly larger and more lordotic cages in ALIF |
| Geddes et al. [26] 2021 | PSF = 13.4° ± 7.1°, ALIF+PSF = 18.3 ± 9.3° | PSF = 8.6 ± 4.4°, ALIF+PSF = 6.1° ± 5.3° | PSF = 4.8 ± 4.5° (27% curve correction), ALIF+PSF = 12.1 ± 6.0° (68% correction), p = 0.053 | NR | ALIF+PSF achieves greater correction of the fractional curve than PSF alone. Though not the primary indication of ALIF, this may help facilitate overall deformity correction and pelvic balance |
| Hofler et al. [43] 2022 | Kickstand = 4.3-cm coronal deviation, 43° major lumbar curve, 23° fractional lumbar curve | Kickstand group = 4.3-cm intraoperative coronal deviation, 1.8-cm postoperative coronal deviation | Preoperative lumbar FC was greater in patients requiring a kickstand (23° vs. 35°, p = 0.02) | NR | Intraoperative kickstand rod placement guided by intraoperative APLCR allows for satisfactory reduction in cases where the fractional coronal curve persists without loss of sagittal plane correction |
| Nonkickstand = 2.2-cm coronal deviation, 35° major lumbar curve, 14° fractional lumbar curve | Nonkickstand group = 0.6-cm intraoperative coronal deviation, 2.1 cm postoperative coronal deviation | ||||
| Zuckerman et al. [27] 2023 | Qiu type A=11.1° | Qiu type A=5.3° | Type C patients had the most LSF curve correction (p = 0.023 for change in LSF curve by 9.2°) | NR | Greater correction of LSF curve was seen in Qiu type C patients compared to type A and type B. More TLIFs were associated with greater amount of LSF curve correction. No clear trends seen regarding LSF curve change and postoperative outcomes |
| Qiu type B=12.7° | Qiu type B=7.6° | ||||
| Qiu type C=15.6° | Qiu type C=6.4° |
PSIF, open posterior spinal instrument fusion; TLIF, transforaminal lumbar interbody fusion; ALIF, anterior lumbar interbody fusion; LLIF, lateral lumbar interbody fusion; FC, fractional curve; LOS, length of stay; LT, lower thoracic; UT, upper thoracic; cMIS, circumferential minimally invasive surgery; NR, not reported; PSF, posterior spinal fusion; APLCR, anteroposterior long cassette radiograph.