Posterolateral Lumbar Interbody Fusion Research Articles

Unilateral pedicle screw fixation with interbody fusion in lumbar degenerative disease

ObjectiveUnilateral transpedicular screw is widely used in lumbar spine surgery due to its primary role in enhancing arthrodesis with less tissue damage when combined with posterolateral lumbar interbody fusion (PLIF). Unilateral instrumentation can achieve similar outcomes to those of bilateral instrumentation. Its advantage is that it precludes the possibility of damaging the contralateral soft tissues and muscles. Our study assess the operative efficacy and benefits of unilateral pedicle screw (PS) fixation and decompression with interbody diagonal cage for lower lumbar degenerative diseases (LDD). Patients and MethodsA total of 60 consecutive patients who underwent either a bilateral or unilateral procedure (30 patients in each group) for treating lower LDD were included in this study. Radiological and clinical assessments were performed at 3, 6, and 12 months after surgery to assess interbody fusion rates and clinical outcomes. ResultsNo significant differences were observed between the two cohorts regarding age, gender, weight, presence of comorbidities, or baseline neurologic deficit. The unilateral cases showed statistically significant less surgical trauma in terms of fluoroscopy time, operative time, intraoperative blood transfusion, and length of incision. The clinical and radiological outcomes in both cohorts were quite similar. ConclusionBoth unilateral and bilateral PS fixations with PLIF have quite similar outcomes for LDD. However, based on its minimal invasiveness, the unilateral approach can be an attractive alternative to bilateral instrumentation. Our study recommends unilateral short-segment fixation as an appropriate choice in selected cases.

Retrospective Case Control Study: Clinical and Computer Tomographic Fusion and Subsidence Evaluation for Single Level Uniportal Endoscopic Posterolateral Approach Transforaminal Lumbar Interbody Fusion Versus Microscopic Minimally Invasive Transforaminal Interbody Fusion.

Retrospective comparative study. Assessment of difference in clinical and computer tomographic outcomes between the 2 cohorts. Computer tomographic evaluation by Bridwell's grade, Kim's stage, Kim's subsidence grade and clinical evaluation by VAS, ODI and McNab's criteria on both cohorts. 33 levels of Endo-TLIF and 22 levels of TLIF were included, with a mean follow up of 14.3 (10-24) and 22.9 (13-30) months respectively. Both Endo-TLIF and TLIF achieved significant improvement of pain and ODI at post-operative 4 week, 3 months and at final follow up with VAS 4.39 ± 0.92, 5.27 ± 1.16 and 5.73 ± 1.21in Endo-TLIF and 4.55 ± 1.16, 5.05 ± 1.11 and 5.50 ± 1.20 in TLIF respectively and ODI at post-operative 1 week, 3 months and final follow up were 43.15 ± 6.57, 49.27 ± 8.24 and 51.73 ± 9.09 in Endo-TLIF and 41.73 ± 7.98, 46.18± 8.46 and 49.09 ± 8.98 in TLIF respectively, P < 0.05. Compared to TLIF, Endo-TLIF achieved better VAS with 0.727 ± 0.235 at 3 months and 0.727 ± 0.252 at final follow up and better ODI with 3.88 ± 1.50 at 3months and 3.42 ± 1.63 at final follow up, P < 0.05. At 6 months radiological evaluation comparison of the Endo-TLIF and TLIF showed significant with more favorable fusion rate in Endo-TLIF of -0.61 ± 0.12 at 6 months and -0.49 ± 0.12 at 1 year in Bridwell's grading and 0.70 ± 0.15 at 6 months and 0.56 ± 0.14 at 1 year in Kim's stage.There is less subsidence of 0.606 ± 0.18 at 6 months and -0.561 ± 0.20 at 1 year of Kim's subsidence grade, P < 0.05. Application of single level uniportal endoscopic posterolateral lumbar interbody fusion achieved better clinical outcomes and fusion rate with less subsidence than microscopic minimally invasive transforaminal lumbar interbody fusion in mid-term evaluation for our cohorts of patients.

Uniportal Full Endoscopic Posterolateral Transforaminal Lumbar Interbody Fusion with Endoscopic Disc Drilling Preparation Technique for Symptomatic Foraminal Stenosis Secondary to Severe Collapsed Disc Space: A Clinical and Computer Tomographic Study with Technical Note

Background: Severe collapsed disc secondary to degenerative spinal conditions leads to significant foraminal stenosis. We hypothesized that uniportal posterolateral transforaminal lumbar interbody fusion with endoscopic disc drilling technique could be safely applied to the collapsed disc space to improve patients’ pain score, restore disc height, and correct the segmental angular parameters. Methods: We included patients who met the indication criteria for lumbar fusion and underwent uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion with pre-operative Computer Tomography mid disc height of less than or equal to 5 mm and MRI of Grade 3 Foraminal Stenosis. Visual analogue scale and computer tomography pre-operative and post-operative sagittal disc height in the anterior, middle and posterior part of the disc; sagittal focal segmental angle; mid coronal disc height and coronal wedge angles were evaluated. Results: 30 levels of Endo-TLIF were included, with a mean follow up of 12 months. The mean improvement in decreasing pain score was 2.5 ± 1.1, 3.2 ± 0.9 and 4.3 ± 1.0 at 1 week post operation, 3 months post operation and at final follow up, respectively, p < 0.05. There was significant increase in mid sagittal computer tomographic anterior, middle and posterior disc height of 6.99 ± 2.30, 6.28 ± 1.44, 5.12 ± 1.79 mm respectively, p < 0.05. CT mid coronal disc height showed an increase of 7.13 ± 1.90 mm, p < 0.05. There was a significant improvement in the CT coronal wedge angle of 2.35 ± 4.73 and the CT segmental focal sagittal angle of 1.98 ± 4.69, p < 0.05. Conclusion: Application of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion in patients with severe foraminal stenosis secondary to severe collapsed disc space significantly relieved patients’ pain and restored disc height without early subsidence or exiting nerve root dysesthesia in our cohort of patients.

Technical Considerations of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion: A Review of Its Early Clinical Results in Application in Adult Degenerative Scoliosis

Uniportal endoscopic posterolateral lumbar interbody fusion (Endo-TLIF) provides one of the least invasive forms of minimally invasive surgery, allowing large size cages which are commercially available for open and tubular microscopic transforaminal lumbar interbody fusion (TLIF) to be inserted through this approach. We studied the effect of such a technique on a series of patients with low-grade degenerative scoliosis. Endo-TLIF was applied to patients who had 10°-40° of degenerative adult scoliosis. Pre- and postoperative 1-week, 3-month, and final follow-up clinical status of visual analog scale, Oswestry Disability Index, perioperative complications, and Macnab criteria were collected. Roentgenogram to assess changes in Cobb angles was done. There was statistically significant improvement of preoperative, 1-week postoperative, 3-month postoperative, and final follow-up mean of visual analog scale scores with 7.72 (5-10), 3.68 (3-6), 2.88 (2-4), and 1.96 (1-3), respectively, and with Oswestry Disability Index mean of 70.4 (52-86), 35.12 (26-56), 27.68 (24-38), and 24 (20-28), respectively (P < 0.05). In terms of Macnab criteria, 100% had good to excellent result. In terms of scoliosis measured by Cobb angle, there was statistically significant improvement. Endo-TLIF is a safe and effective procedure in mild to moderate degenerative scoliosis with good early clinical results and improvement in coronal Cobb angle. It can be considered as an option if a short segment(s) fusion is planned for adult degenerative scoliosis.

Vertebral fracture after removing pedicle screws used for posterior lumbar interbody fusion: A case report

It is uncommon to remove pedicle screws after posterolateral lumbar interbody fusion (PLIF), and there are a few case reports of vertebral fracture involving holes remaining after screw removal. We report a case of the vertebral fracture after removing pedicle screws instrumented for PLIF. A 66-year-old woman with osteopenia, who underwent PLIF at L4–S1 10 years earlier, underwent PLIF at L3–L4 to correct adjacent-segment degeneration. We removed L5 and S1 pedicle screws, and inserted L3 pedicle screws. After surgery, she presented with severe progressive low back pain. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed an L5 body fracture involving the pedicle screw holes. Revision surgery, including posterolateral fusion from L3 to S2 alar iliac and L5 vertebroplasty, was performed. One year after the revision surgery, the patient remained pain-free and returned to normal activity. Possible reasons for instrumented vertebral body fracture after pedicle screw removal are decrease of vertebral mass, increased mechanical stress caused by PLIF at the adjacent segment, stress-shielding-related osteopenia, and spinal imbalance. Vertebral body fractures associated with spinal implant removal are rare, but possible, especially in elderly patients with osteopenia and osteoporosis.

Comparison of Posterior Lumbar Interbody Fusion and Posterolateral Lumbar Fusion in Monosegmental Vacuum Phenomenon within an Intervertebral Disc.

Study DesignRetrospective.PurposeTo compare the clinical and radiological outcomes of posterolateral lumbar interbody fusion (PLIF) and posterolateral lumbar fusion (PLF) in monosegmental vacuum phenomenon within an intervertebral disc.Overview of LiteratureThe vacuum phenomenon within an intervertebral disc is a serious form of degenerative disease that destabilizes the intervertebral body. Outcomes of PLIF and PLF in monosegmental vacuum phenomenon are unclear.MethodsMonosegmental instrumented PLIF and PLF was performed on 84 degenerative lumbar disease patients with monosegmental vacuum phenomenon (PLIF, n=38; PLF, n=46). Minimum follow-up was 24 months. Clinical outcomes of leg and back pain were assessed using visual analogue scales for leg pain (LVAS) and back pain (BVAS), and the Oswestry disability index (ODI). The radiographic outcome was the estimated bony union rate.ResultsLVAS, BVAS, and ODI improved in both groups. There was no significant difference in the degree of these improvements between PLIF and PLF patients (p>0.05). Radiological union rate was 91.1% in PLIF group and 89.4% in PLF group at postoperative 24 months (p>0.05).ConclusionsNo significant differences in clinical results and union rates were found between PLIF and PLF patients. Selection of the operation technique will reflect the surgeon's preferences and patient condition.

Response to: Comparison of Posterior Lumbar Interbody Fusion and Posterolateral Lumbar Fusion in Monosegmental Vacuum Phenomenon within an Intervertebral Disc.

Study design Retrospective. Purpose To compare the clinical and radiological outcomes of posterolateral lumbar interbody fusion (PLIF) and posterolateral lumbar fusion (PLF) in monosegmental vacuum phenomenon within an intervertebral disc. Overview of literature The vacuum phenomenon within an intervertebral disc is a serious form of degenerative disease that destabilizes the intervertebral body. Outcomes of PLIF and PLF in monosegmental vacuum phenomenon are unclear. Methods Monosegmental instrumented PLIF and PLF was performed on 84 degenerative lumbar disease patients with monosegmental vacuum phenomenon (PLIF, n=38; PLF, n=46). Minimum follow-up was 24 months. Clinical outcomes of leg and back pain were assessed using visual analogue scales for leg pain (LVAS) and back pain (BVAS), and the Oswestry disability index (ODI). The radiographic outcome was the estimated bony union rate. Results LVAS, BVAS, and ODI improved in both groups. There was no significant difference in the degree of these improvements between PLIF and PLF patients (p>0.05). Radiological union rate was 91.1% in PLIF group and 89.4% in PLF group at postoperative 24 months (p>0.05). Conclusions No significant differences in clinical results and union rates were found between PLIF and PLF patients. Selection of the operation technique will reflect the surgeon's preferences and patient condition.

Operative Management of Lumbar Disc Herniation with End Plate Modic Changes Necessitates More Definite Procedures

Introduction Nucleotomy through interlaminar fenestration has been the standard operation for lumbar disc herniation, but it does not always work well in clinical practice. End plate Modic changes are strongly linked with lower back pain, and Modic changes in the end plates of the herniation level may be one reason for the unpredictable result of nucleotomy alone. Studies on more definite surgical procedures for lumbar disc herniation with end plate Modic changes are still rare. To compare the clinical outcomes between two surgical options, nucleotomy alone and nucleotomy with additional posterolateral lumbar interbody fusion (PLIF), for lumbar disc herniation patients with end plate Modic changes, and to testify the hypothesis that end plate Modic change is an indication of interbody fusion for operative management of lumbar disc herniation. Materials and Methods A total of 91 patients who complained about both lower extremity radicular pain and lower back pain (lower back pain more severe than leg pain) were included, and all of them were of single segment disc herniation with Modic changes in the corresponding lumbar degenerative end plates. Of the 91 patients, 47 were treated with nucleotomy alone and 44 were treated with posterolateral lumbar interbody fusion (PLIF) in addition to nucleotomy. They were followed up for at least 2 years. Clinical outcomes were evaluated according to the Japanese Orthopaedic Association (JOA) score and visual analogue scale (VAS) for lower back pain and VAS for lower extremity radicular pain before operation and at each follow-up, and the results before surgery and at 18 months after operation were statistically compared. Results In both the groups, the JOA scores, as well as VAS, for lower back pain significantly improved 18 months after surgery. The improvement rate of JOA score and power of improvement of VAS for lower back pain also showed significant difference between the two groups, being better in nucleotomy with PLIF procedure than in nucleotomy alone procedure. On the contrary, the mean VAS of lower extremity radicular pain showed a significant reduction in both groups at the follow-up of 18 months after operation. However, a significant difference of the power of this improvement between both the groups was not found. Conclusion Operative management of lumbar disc herniation with end plate Modic changes necessitates more definite procedures in addition to nucleotomy. PLIF is a good and reliable option. Disclosure of Interest None declared

Risk factors for adjacent segment degeneration after surgical correction of degenerative lumbar scoliosis

Background:Degenerative lumbar scoliosis surgery can lead to development of adjacent segment degeneration (ASD) after lumbar or thoracolumbar fusion. Its incidence, risk factors, morbidity and correlation between radiological and clinical symptoms of ASD have no consensus. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and certain imperative parameters.Materials and Methods:98 patients who had undergone surgical correction and lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative lumbar scoliosis with a minimum 5 year followup were included in the study. We evaluated the correlation between the occurrence of radiologic adjacent segment disease and imperative patient parameters like age at operation, sex, body mass index (BMI), medical comorbidities and bone mineral density (BMD). The radiological parameters taken into consideration were Cobb's angle, angle type, lumbar lordosis, pelvic incidence, intercristal line, preoperative existence of an ASD on plain radiograph and magnetic resonance imaging (MRI) and surgical parameters were number of the fusion level, decompression level, floating OP (interlumbar fusion excluding L5-S1 level) and posterolateral lumbar interbody fusion (PLIF). Clinical outcomes were assessed with the Visual Analogue Score (VAS) and Oswestry Disability Index (ODI).Results:ASD was present in 44 (44.9%) patients at an average period of 48.0 months (range 6-98 months). Factors related to occurrence of ASD were preoperative existence of disc degeneration (as revealed by MRI) and age at operation (P = 0.0001, 0.0364). There were no statistically significant differences between radiological adjacent segment degeneration and clinical results (VAS, P = 0.446; ODI, P = 0.531).Conclusions:Patients over the age of 65 years and with preoperative disc degeneration (as revealed by plain radiograph and MRI) were at a higher risk of developing ASD.

The Effects of Design and Positioning of Carbon Fiber Lumbar Interbody Cages and Their Subsidence in Vertebral Bodies

A biomechanical study using human cadaveric lumbar spines. To determine the strength and stiffness of 3 carbon fiber cage designs in axial compression. To assess the effects of bone mineral density (BMD) on vertebral endplate failure with respect to the different cage patterns. Unilateral transforaminal approaches are gaining popularity compared with posterolateral lumbar interbody fusion. With differences in the inherent strengths of each quadrant of the endplate, the effect of different cage designs and their location on the endplate may affect subsidence and fusion success. BMD measurements were obtained from 30 human spinal segments from L3 to L5. Discectomies were performed and cages were placed on the cephalad endplate of each vertebra in 3 configurations: 2 small posterolateral rectangular cages; 1 small anterior banana cage; and 1 small central rectangular cage. Each segment was tested under compression until endplate failure was recorded. Two-way analysis of variance was used to test for the effects of cage design on cage subsidence and endplate failure. Analysis of covariance was conducted to test for the effects of age, BMD, and vertebral levels on the failure load and stiffness for each cage design. Cage design was not significant in affecting failure force across the endplate. There were insignificant differences comparing stiffness in compression for the 3 different cage placements patterns. Low BMD adversely affected failure force and construct stiffness across all 3 cage patterns. Cage design and position do not significantly affect failure of the construct or stiffness in compression across the endplate. BMD significantly affects both failure forces and stiffness but is not dependent on the positioning or design of the cage.

Short fusion versus long fusion for degenerative lumbar scoliosis

The extent of fusion for degenerative lumbar scoliosis has not yet been determined. The purpose of this study was to compare the results of short fusion versus long fusion for degenerative lumbar scoliosis. Fifty patients (mean age 65.5 +/- 5.1 years) undergoing decompression and fusion with pedicle screw instrumentation were evaluated. Short fusion was defined as fusion within the deformity, not exceeding the end vertebra. Long fusion was defined as fusion extended above the upper end vertebra. The lower end vertebra was included in the fusion in all the patients. The short fusion group included 28 patients and the long fusion group included 22 patients. Patients' age and number of medical co-morbidities were similar in both the groups. The number of levels fused was 3.1 +/- 0.9 segments in the short fusion group and 6.5 +/- 1.5 in the long fusion group. Before surgery, the average Cobb angle was 16.3 degrees (range 11-28 degrees ) in the short fusion group and 21.7 degrees (range 12-33 degrees ) in the long fusion group. The correction of the Cobb angle averaged 39% in the short fusion group and 72% in the long fusion group with a statistical difference (P = 0.001). Coronal imbalance improved significantly in the long fusion group more than in the short fusion group (P = 0.03). The correction of lateral listhesis was better in the long fusion group (P = 0.02). However, there was no difference in the correction of lumbar lordosis and sagittal imbalance between the two groups. Ten of the 50 patients had additional posterolateral lumbar interbody fusion at L4-5 or L5-S1. The interbody fusion had a positive influence in improving lumbar lordosis, but was ineffective at restoring sagittal imbalance. Early perioperative complications were likely to develop in the long fusion group. Late complications included adjacent segment disease, loosening of screws, and pseudarthrosis. Adjacent segment disease developed in ten patients in the short fusion group, and in five patients in the long fusion group. In the short fusion group, adjacent segment disease occurred proximally in all of the ten patients. Loosening of distal screws developed in three patients, and pseudarthrosis at L5-S1 in one patient in the long fusion group. Reoperation was performed in four patients in the long fusion group and three patients in the short fusion group. In conclusion, short fusion is sufficient for patients with small Cobb angle and good spinal balance. For patients with severe Cobb angle and rotatory subluxation, long fusion should be carried out to minimize adjacent segment disease. For patients who have severe sagittal imbalance, spinal osteotomy is an alternative technique to be considered. As long fusion is likely to increase early perioperative complications, great care should be taken for high-risk patients to avoid complications.