Postoperative Segmental Lordosis Research Articles

Sagittal Deformity Correction during the Lateral Transpsoas Approach with Hyperlordotic Interbody Grafting, Adjunctive ALL Release, and Subsequent Smith–Peterson Osteotomy

Introduction Traditionally, surgical intervention for patients with thoracolumbar sagittal imbalance relied on posterior column shortening techniques such as the Smith–Peterson osteotomy (SPO) and pedicle subtraction osteotomy (PSO). The lateral retroperitoneal, transpsoas approach has been proven to afford significant coronal deformity correction; however, the evidence for its use in the sagittal deformity correction is less robust. Recently, the use of hyperlordotic grafts has provided all the benefits of the transpsoas approach while also allowing for sagittal deformity correction. Hyperlordotic interbody grafts and a subsequent SPO can theoretically provide a similar sagittal correction as provided by a PSO or multiple SPOs while minimizing the associated morbidities. Materials and Methods This is a retrospective review examining the preoperative and postoperative segmental lordosis after placement of a hyperlordotic cage and subsequent SPO. A total of 22 patient charts were reviewed. The mean patient age was 58.6. There were 8 males and 14 females. A 20-degree hyperlordotic cage was utilized at four intervertebral levels. The 30-degree cage was used at 19 levels. The surgical procedure involved the release of the anterior longitudinal ligament and placement of a hyperlordotic graft (NuVasive CoRoent XL-Hyperlordotic) via the lateral, retroperitoneal, transpsoas approach followed by posterior instrumentation and SPO at that level. In each instance, the hyperlordotic graft and subsequent SPO were part of a large, multilevel deformity correction and were not simply performed as a standalone procedure. Results Hyperlordotic cages were placed from T12–L1 to L4–L5 in this series. A total of 10 cages were placed at the L3–L4 interspace. The mean preoperative lordosis was 0.4 and 4.2 degrees in the 20 and 30-degree cohorts, respectively. The mean postoperative, segmental lordosis was 23.0 and 28.2 degrees in the two groups, yielding a mean correction of 22.6 degrees with the 20-degree cage and 24.0 degrees with the 30-degree cage. The 30-degree cage yielded a sagittal correction of 8.5 to 54.0 degrees. A correction of greater than 30 degrees was achieved in five cases. The single case with less than 10 degrees of lordosis restoration resulted from graft subsidence. The greatest increase in lordosis occurred in patients with the most significant preoperative segmental kyphosis. Conclusion Segmental lordosis increase of approximately 20 to 25 degrees can be expected with the placement of either a 20- or 30-degree hyperlordotic cage via the transpsoas approach with subsequent SPO at that level. This hybrid approach provides a degree of correction similar to a PSO without the associated morbidity.

Radiographic Variables That May Predict Clinical Outcomes in Cervical Disk Replacement Surgery

Retrospective analysis of prospectively collected data. To determine which, if any, radiographic parameters are predictive of clinical outcome after cervical disk replacement (CDR) surgery. It is unclear whether radiographic parameters are predictive of outcome after CDR. An analysis of the radiographic parameters and clinical outcomes of the CDR cohort of the Discover artificial cervical disk IDE trial was performed. Clinical outcome measures included Neck Disability Index (NDI), visual analog pain scale (neck, arm, and shoulder), and SF-36 physical component summary score scores, collected preoperatively and at regularly scheduled postoperative time periods. Patients with at least 1-year follow-up were included. The change in outcomes from baseline was determined at each follow-up interval. The following minimal clinically important difference (MCID) thresholds were applied: -7.5 for NDI, -25 for visual analog pain scale, and +4.1 for physical component summary score. Fifty-six radiographic variables were analyzed to identify factors that may be associated with a poor clinical outcome, defined as failure to achieve the MCID in NDI. A total of 243 patients underwent CDR at 304 levels (182 one level, 61 two level). One hundred seventy-one patients (89 female, 82 male; mean age, 44.2 y; range, 28-67 y) had at least 1-year follow-up. A preoperative disk height of <3.5 mm was associated with a 3.4 times greater risk of not achieving a MCID in NDI (P=0.018). Increasing the functional spinal unit angle by >3 degrees was associated with a 3.5 times greater risk of not achieving a MCID in NDI (P=0.016). There were 21/171 patients (25 levels) who did not achieve the NDI MCID threshold. All of these patients had at least1, and 16/21 of these patients had more than 1 abnormal radiographic finding. Seventy percent of treatment levels had severe or bridging heterotopic ossification at 3-years follow-up, the incidence of which increased linearly with time. Several radiographic variables are predictive of clinical outcomes, including decreased preoperative disk space height and excessive postoperative segmental lordosis.

Intraoperative determination of lumbar prosthesis endplate lordotic angulation to improve motion

The aim of total disc replacement (TDR) is to restore and maintain closer-to-physiology motion. Therefore, the factors that influence postoperative intervertebral motion have to be controlled. Factors such as disc height (DH), postoperative segmental lordosis (SL), implant design and positioning are still recognized to be influent. Otherwise, range of motion (ROM) distribution, between flexion and extension, appear to be influenced by obtaining parallel bearing surfaces, which depends on prosthesis endplate lordotic angulation. To assess in vivo the correlation between an intraoperative parameter (intraoperative segmental lordosis: ISL) and a postoperative parameter (postoperative segmental lordosis: PSL). To determine the advantage of ISL measurement on the improvement of the prosthetic endplate lordotic angulation choice. Radiological comparison between intraoperative and postoperative segmental parameters. Fifty-seven patients who received a TDR at one level, L4–L5 or L5–S1, with different prosthetic endplate lordotic angulations (0°, 5°, and 10°). Twenty-one consecutive patients underwent intraoperative measurement (ISL) on a lateral view, with a spacer at the mid-vertebral bony endplates (Group 1). ISL was correlated using a linear correlation test with PSL. Group 1 postoperative prosthesis endplate lordosis (PEL: angle between the bearing surfaces) were compared to those of 46 patients without intraoperative measurement (Group 2). The mean ISL and PSL angles were 12.2° (7–21°) and 13.9° (8–23°), respectively. We observed a strong linear correlation between ISL and PSL (r=0.78, P <0.006). In Group 1, PEL varied between −1° and 11°, and between −3.7° and 17.8° in Group 2. For 80% of the patients in Group 1, the PEL was less than 5°, versus 33% of the patients in Group 2. Only prostheses with PEL less than 5° had a preserved extension curve in ROM distribution (+3°). Intraoperative measurement of ISL has emerged as a key factor in predicting PSL in TDR. The percentage of parallel bearing surfaces was increased by a prosthesis endplate lordotic angulation choice guided by ISL measurement. This study confirmed the advantage of choosing the adequate lordotic angulation of the prosthesis endplate to restore a physiological motion distribution between flexion and extension.

Effects of lordotic angle of a cage on sagittal alignment and clinical outcome in one level posterior lumbar interbody fusion with pedicle screw fixation.

This study aims to assess the differences in the radiological and clinical results depending on the lordotic angles of the cage in posterior lumbar interbody fusion (PLIF). We reviewed 185 segments which underwent PLIF using two different lordotic angles of 4° and 8° of a polyetheretherketone (PEEK) cage. The segmental lordosis and total lumbar lordosis of the 4° and 8° cage groups were compared preoperatively, as well as on the first postoperative day, 6th and 12th months postoperatively. Clinical assessment was performed using the ODI and the VAS of low back pain. The pre- and immediate postoperative segmental lordosis angles were 12.9° and 12.6° in the 4° group and 12° and 12.0° in the 8° group. Both groups exhibited no significant different segmental lordosis angle and total lumbar lordosis over period and time. However, the total lumbar lordosis significantly increased from six months postoperatively compared with the immediate postoperative day in the 8° group. The ODI and the VAS in both groups had no differences. Cages with different lordotic angles of 4° and 8° showed insignificant results clinically and radiologically in short-level PLIF surgery. Clinical improvements and sagittal alignment recovery were significantly observed in both groups.

Surgical Management of 4-level Cervical Spondylotic Myelopathy

The optimal surgical approach for 4-level cervical spondylotic myelopathy is controversial. The authors compared the clinical outcomes, radiographic changes, and complications of 53 patients who underwent either discontinuous corpectomy and fusion (DCF) with reservation of the middle vertebra (n=29) or laminectomy and fusion (n=24). Neurological function was measured using Nurick's grade and modified Japanese Orthopedic Association scores. The Neck Disability Index was recorded for neck-shoulder pain level evaluation. Patients' satisfaction with the surgery was evaluated using the Short Form 36. Segmental lordosis was measured. Both groups demonstrated significantly improved Nurick's grades and Japanese Orthopedic Association scores (P<.001), and the recovery rate was similar between the groups (59.86% ± 17.63% and 60.18% ± 12.01%, respectively). In terms of Neck Disability Index scores, Short Form 36 scores, and cervical lordosis measurements, no significant intergroup differences were found preoperatively. Mean postoperative Neck Disability Index scores were significantly lower in the DCF group (12.31 ± 1.91) than in the laminectomy group (15.04 ± 3.09; P=.000). Mean postoperative segmental lordosis was significantly higher in the DCF group (14.24 ± 2.29) than in the laminectomy group (9.96 ± 2.14; P=.001). The Short Form 36 scores significantly improved in both groups postoperatively (P<.01). Relative to the DCF group, the laminectomy group had a significantly longer operative time (192.25 ± 33.47 vs 192.25 ± 33.47 minutes, respectively; P<.01) and significantly more operative blood loss (455.41 ± 140.46 vs 253.79 ± 77.94 mL, respectively; P<.01). Discontinuous corpectomy and fusion with reservation of the middle vertebra is a safe and effective surgical treatment for 4-level cervical spondylotic myelopathy that results in significant functional improvement in most patients.

Segmental lumbar sagittal correction after bilateral transforaminal lumbar interbody fusion

In this paper the authors sought to determine the segmental lumbar sagittal contour change after bilateral transforaminal lumbar interbody fusion (TLIF). Between March 2007 and October 2010, 42 consecutive patients (57 levels) underwent bilateral TLIF. Standard preoperative and 6-week postoperative standing lumbar spine radiographs were examined. Preoperative and postoperative segmental lordosis was determined by manual measurements using the Cobb method. The difference between the preoperative and postoperative values were calculated and analyzed for statistical significance. The mean preoperative segmental alignment was 8.1°. The mean postoperative alignment was 15.3°, with a mean correction of 7.2° per segment. The largest gain in lordosis was obtained at the L5-S1 level (10.1°). There was a significant difference between the preoperative and postoperative values (p = 5 × 10(-9)). There was no significant difference in mean segmental correction between levels. Improvement in lordosis was higher in multilevel fusions (9.8°) than in single-level fusions (5.2°) (p = 0.047). There was an inverse correlation between preoperative sagittal lordosis measurement and change in lordosis (r = -0.599). A significant improvement in lumbar lordosis can be gained by preforming bilateral facetectomies in TLIF with posterior compression. This procedure provides an additional option to a spine surgeon's armamentarium in dealing with significant lumbar sagittal plane deformities.

Adjacent Segment Degeneration After Lumbar Interbody Fusion With Percutaneous Pedicle Screw Fixation for Adult Low-Grade Isthmic Spondylolisthesis: Minimum 3 Years of Follow-up

Although favorable clinical outcomes have been reported for instrumented lumbar interbody fusion (LIF), adjacent segment degeneration (ASD) has been reported as a long-term complication after LIF. To investigate ASD after instrumented LIF performed at a single level and only for the homogeneous disease of adult low-grade isthmic spondylolisthesis. A total of 128 patients who had undergone LIF for the treatment of adult low-grade isthmic spondylolisthesis involving the lower lumbar spine at our institution between February 2001 and December 2004 were retrospectively reviewed by chart review and telephone survey. Of them, 103 patients with a minimum of a 36-month follow-up period were enrolled in this study. The mean age was 48.5 years. The average follow-up period was 59 months. Clinical and radiological data related to segmental lordosis (SL), whole lumbar lordosis, sacral slope, pelvic tilt, pelvic incidence, and L1 axis S1 distance were analyzed to identify significant risk factors for ASD. The overall incidence of ASD was 10.6% (11/103). The incidences of radiographic and symptomatic ASD were 8.7% (9/103) and 1.9% (2/103), respectively. All patients improved clinically and functionally during the follow-up period. Postoperative SL, preoperative SL, whole lumbar lordosis, and L1 axis S1 distance were significant risk factors for ASD. Only SL was a significant risk factor for both the preoperative and postoperative states. ASD may occur at a relatively lower incidence in adult low-grade isthmic spondylolisthesis compared with other degenerative lumbar spinal diseases. SL is significantly correlated with ASD, whereas mechanical alterations caused by LIF are less likely to affect the adjacent segment. Restoration of normal SL is important for preventing ASD, and long-term follow-up is necessary.

Effect of intraoperative position used in posterior lumbar interbody fusion on the maintenance of lumbar lordosis

The objective in this study was to compare retrospectively the use of different operating tables with different positions for posterior lumbar interbody fusion (PLIF) and the effect on intraoperative and postoperative lumbar lordosis and segmental lordosis. One hundred seventy-two patients with degenerative disease of the lumbar spine who underwent posterior decompression and PLIF in which a 0 degrees polyetheretherketone cage and pedicle screw fixation were used were evaluated. Ninety-one patients underwent surgery on a Wilson table (Group I) and 81 patients were treated on an OSI Jackson spinal table (Group II). Preoperative standing, intraoperative prone, and postoperative standing lateral radiographs were obtained in each patient. The total lumbar and segmental lordosis were compared and analyzed according to the position in which the patients were placed for their operation. The intraoperative total lumbar lordosis was significantly decreased compared with the preoperative value. The postoperative total lumbar lordosis was similar, however, to the preoperative values in both groups. In Group I, the intraoperative segmental lordosis of L2-3 and L3-4 was significantly decreased compared with the pre-operative segmental lordosis. In Group II, the intraoperative segmental lordosis of L3-4, L4-5, L5-S1, and L4-S1 was significantly decreased compared with the preoperative segmental lordosis. The postoperative segmental lordosis of L4-5 was significantly decreased and L2-3 was significantly increased compared with the preoperative lordosis in both groups. Intraoperative position does not affect postoperative total lumbar lordosis and segmental lordosis in short-segment PLIF of the lumbar spine in a retrospective analysis of the surgical procedure to maintain lordosis.

Factors Affecting Segmental Lordotic Angle After Posterior Lumbar Interbody Fusion Using Metal Cage

- Abstract - Study Design: This is a retrospective study Objectives: We tried to find out what kind of factors affect the segmental lordotic angle improvement after performing posterior lumbar interbody (PLIF) fusion using a metal cage. The study was done using radiographic measurements. Summary of Literature Review: For degenerative spinal disease, PLIF with using a metal cage is an effective way to fuse and restore segmental lordosis of the lumbar spine. Materials and Methods: The study included 104 patients (65 males, 39 females). Radiographs of the antero-posterior, lateral, flexion and extension views that were taken during the preoperative period and the follow-up 6 months were evaluated for the L4-5 segmental lordosis angle, cage invagination, cage position and disc height. Then, statistical analysis was performed using the Pearson method to determine which factors affected the segmental lordotic angle correction. Results: The increase of the anterior disc height on the postoperative lateral radiograph (γ =0.303, p<0.01) and the increase of lordosis on the preoperative extension radiograph (γ =0.384, p<0.01) showed statistically positive correlation with the increase of the postoperative segmental lordosis angle. When comparing between the 4°and 8°cages, the more angle the cage had, the more segmental angle was restored and this was statistically correlated (P<0.05). However, the amount of segmental lordosis angle correction was not as much as the angle of the cage that was used. Other factors such as cage invagination and cage position didn't show statistical correlation. Conclusions: Posterior lumbar interbody fusion using a metal cage is useful method for restoring the lumbar segmental lordosis angle only if the disc is flexible enough to be distracted (ED note: distracted is the word you want?) sufficiently intraoperatively or if it allows good segmental lordosis, as seen on the preoperative extension radiograph. Correction of the segmental lordosis angle using a wedged cage with a larger angle was not always satisfactory because it did not restore as much angle as the angle of cage that was used.