Jen-Chung Liao

Inflammatory characteristics of rhBMP-2 in vitro and in an in vivo rodent model.

Study Design. In vivo and in vitro model. Objective. Investigate soft-tissue inflammation caused by rhBMP-2. Summary of Background Data. Although rhBMP-2 produces excellent rates of fusion in the spine, dysphagia and respiratory compromise have occurred when used in the neck. The mechanism of the swelling and inflammatory response has yet to be fully elucidated. Methods. ELISA kits (IL-6, IL-10, TNF-&agr;) were used to measure cytokine levels at different concentrations of rhBMP-2. Absorbable collagen sponges were implanted with or without different concentrations of rhBMP-2 into the backs of rats subcutaneously (SC) and intramuscularly (IM). Magnetic resonance imaging was used to measure inflammation at 3 hours and 2, 4, and 7 days. The inflammatory volumes were measured and compared using MIPAV software. Rats were killed after 7 days and studied. Results. IL-6, IL-10, and TNF-&agr; release was dose-dependent. Soft-tissue edema after rhBMP-2 implantation was also dose-dependent, peaking at 3 hours SC, after SC and IM implantations, and on day 2 IM after IM implantation. All formed a granuloma-type mass after SC insertion. The mass was much larger in the 10 and 20 &mgr;g/10 &mgr;L (high-concentration) groups. The inflammatory response did not diffuse across physiologic barriers (subcutaneous fascia). Both high-dose groups were associated with encapsulated hematomas and a significant increase in the inflammatory zone. Conclusion. Swelling and inflammation after rhBMP-2 use are dose-dependent. Swelling may be due to direct contact as well as spread in the plane of access. The causes are a robust inflammatory reaction as well as sterile seroma and encapsulated hematoma formation.

Effect of Sagittal Alignment on Kinematic Changes and Degree of Disc Degeneration in the Lumbar Spine : An Analysis Using Positional MRI

Study Design. Retrospective analysis using positional MRI. Objective. To determine the effects of total sagittal lordosis on spinal kinematics and degree of disc degeneration in the lumbar spine. Summary of Background Data. Changes in sagittal lordosis alter the load on the spine and may affect spinal mobility. There is increasing recognition of the clinical impact that sagittal alignment has on back pain, especially its possible role in accelerating adjacent segment degeneration after spinal fusion. However, its relationship to segmental mobility and degeneration of the lumbar spine has yet to be determined. Methods. Four hundred and thirty patients who had low back pain with or without leg pain (241 males and 189 females) with a mean age of 42.98 years (range, 16–85 years) were included. Total sagittal lordosis (T12-S1) was divided into three groups; Group A: Straight or Kyphosis (<20°, n = 84), Group B: Normal lordosis (20–50°, n = 294), and Group C: Hyperlordosis (>50°, n = 52). The degree of disc degeneration was graded using midsagittal T2-weighted MR images. Segmental mobility, including translational motion and angular variation, was measured using positional MRI. Their relationship with total segmental lordosis was identified. Results. When compared with group B, the segmental motion in group C tended to be lower at the border of lordosis and higher at the apex of lordosis, with a significant difference in angular motion at L2–L3. The contrary finding was identified in group A, which had a higher segmental motion at border segments and lower motion at apical segments of lordosis, with significant difference of translational motion at L3–L4 and angular motion at L1–L2. Apical segments contributed more, whereas border segments contributed less to the total angular mobility in more lordotic spines. The opposite was seen in more kyphotic spines. Disc degeneration tended to be greater at all levels in group C, and at L1–L2 and L5–S1 in group A. Conclusion. Changes in sagittal alignment may lead to kinematic changes in the lumbar spine. This may subsequently influence load bearing and the distribution of disc degeneration at each level. Sagittal alignment, disc degeneration, and segmental mobility likely have a reciprocal influence on one another.

Transpedicular grafting after short-segment pedicle instrumentation for thoracolumbar burst fracture: calcium sulfate cement versus autogenous iliac bone graft.

Study Design. A retrospective clinical and radiographic study was performed. Objective. To compare 2 grafting materials of anterior augmentation for thoracolumbar burst fractures: transpedicular cancellous bone (TPCB) grafting and transpedicular calcium sulfate grafting and to decide whether calcium sulfate cement can replace autogenous cancellous bone applied in anterior vertebral body augmentation after posterior short-segment instrumentation. Summary of Background Data. Additional TPCB grafting was developed as an alternative to prevent early implant failure. However, the results are inconsistent and donor-site complications are a major concern. Calcium sulfate has been offered as a bone substitute for treating patients with metaphysis fractures or bone defect, but the results of application in spinal surgeries are uncertain. Methods. Fifty-one patients with a single-level thoracolumbar burst fracture for treatment with short-segment pedicle screw fixation were enrolled in the study. Fractures in group 1 patients were reinforced with TPCB (n = 31), and fractures in group 2 patients were augmented with transpedicular calcium sulfate cement (TPCSC; n = 20). All patients were followed-up at least 2 years after surgery. Radiographic parameters and clinical outcomes were compared between the 2 groups. Results. The 2 groups were similar in age, sex, fracture levels, preoperative neurologic status distribution, and the associated injuries. The TPCB group had a longer period of follow-up (52.7 ± 4.9 vs. 28.6 ± 3.5 months, P < 0.001). Blood loss and operation time were less in the TPCSC group (247.5 ± 164.2 vs. 600.0 ± 403.1 mL, P = 0.001 and 161.7 ± 28.5 vs. 227.2 ± 43.6 minutes, P < 0.001). Radiographic parameters and clinical outcomes were similar in both groups. The TPCSC group had no surgical complication, but the TPCB group revealed 2 cases with wound infection after surgery. The failure rate, defined as an increase of 10° or more in loss of correction or implant failure, was also not significantly different (TPCB = 9.6% and TPCSC = 15%; P = 0.565). All patients with partial neurologic deficits initially improved at the final follow-up. Conclusion. Additional TPCB grafting after posterior short-segment instrumentation remains a reliable surgical method for correcting and maintaining sagittal alignment and vertebral body height in thoracolumbar burst fractures. Calcium sulfate cement also proved to be an effective bone substitute used in spinal surgeries for patients with thoracolumbar burst fractures.

Surgical risks and perioperative complications of instrumented lumbar surgery in patients with liver cirrhosis

Background: Patients with liver cirrhosis have high surgical risks due to malnutrition, impaired immunity, coagulopathy, and encephalopathy. However, there is no information in English literature about the results of liver cirrhotic patients who underwent instrumented lumbar surgery. The purpose of this study is to report the perioperative complications, clinical outcomes and determine the surgical risk factors in cirrhotic patients. Methods: We retrospectively reviewed 29 patients with liver cirrhosis who underwent instrumented lumbar surgery between 1997 and 2009. The hepatic functional reserves of the patients were recorded according to the Child-Turcotte-Pugh scoring system. Besides, fourteen other variables and perioperative complications were also collected. To determine the risks, we divided the patients into two groups according to whether or not perioperative complications developed. Results: Of the 29 patients, 22 (76%) belonged to Child class A and 7 (24%) belonged to Child class B. Twelve patients developed one or more complications. Patients with Child class B carried a significantly higher incidence of complications than those with Child class A (p = 0.011). In the Child class A group, patients with 6 points had a significantly higher incidence of complications than those with 5 points (p = 0.025). A low level of albumin was significantly associated with higher risk, and a similar trend was also noted for the presence of ascites although statistical difference was not reached. Conclusion: The study concludes that patients with liver cirrhosis who have undergone instrumented lumbar surgery carry a high risk of developing perioperative complications, especially in those with a Child-Turcotte-Pugh score of 6 or more.

Low-intensity pulsed ultrasound enhances healing of laminectomy chip bone grafts on spinal fusion: a model of posterolateral intertransverse fusion in rabbits.

BACKGROUND Laminectomy-derived chip bone graft was usually used in spinal fusion; however, the result of this kind of local bone used in lumbar posterolateral fusion is uncertain. This study tested the hypotheses that low-intensity pulsed ultrasound (LIPU) can accelerate the healing process of laminectomy bone chips in a spinal fusion and enhance the union rate. METHODS Forty-eight rabbits were randomly divided into three groups for the spinal unilateral uninstrumented posterolateral fusion of L5-L6: autologous iliac bone graft (AIBG), laminectomy chip bone graft (LCBG), LCBG plus LIPU (LCBG + LIPU). Each group was subdivided into 6-week and 12-week subgroups. All rabbits were subjected to radiographic examination and manual testing. All successful spinal fusion specimens received biomechanical testing and a histologic examination. RESULTS The LCBG + LIPU group had the highest successful fusion rate at 6-week and 12-week examination (75% and 100%, respectively). At 6 weeks, the average maximum toque at failure values of the fusion masses for the LCBG + LIPU group was significantly higher than that for the LCBG group (p = 0.034). The average maximum torque of the 12-week LCBG + LIPU group was significantly higher than those of the 12-week AIBG and 12-week LCBG groups (p = 0.040 and p = 0.026, respectively). CONCLUSIONS This study suggested that LIPU can enhance bone healing. With augmentation by LIPU, laminectomy chip bone used in lumbar posterolateral fusion can achieve a similar fusion rate and stronger fusion mass than those of an AIBG.

Two additional augmenting screws with posterior short-segment instrumentation without fusion for unstable thoracolumbar burst fracture – Comparisons with transpedicular grafting techniques

Background Transpedicular grafting techniques with posterior short-segment instrumentation have demonstrated to prevent high implant failure in unstable thoracolumbar burst fractures. We tested our hypothesis that short-segment instrumentation with two additional augmenting screws in the injured vertebra could provide stability and was similar to those of the transpedicular grafting technique. Methods Twenty patients belonged to group A; treated with short-segment pedicle screw fixation and reinforced by two augmenting screws at the fractured vertebra. Group B had thirty-one patients; the fractured vertebra was augmented with transpedicular autogenous bone graft. Group C had twenty patients; the injured vertebra was strengthened with calcium sulfate cement. Clinical outcome and radiographic parameters were compared. Results Group A had the least blood loss (101.7 ± 72.5 vs. 600 ± 403.1 vs. 247.5 ± 164.2 ml, p < 0.001) and the least operation time (142.0 ± 57.2 vs. 227.2 ± 43.6 vs. 161.6 ± 28.5 min, p < 0.001). However, group A had the highest collapsed rate of the body height at the 18-month follow-up (10.5 ± 7.0 vs. 4.6 ± 4.8 vs. 7.2 ± 8.5%, p = 0.002). The failure rate, include implant failure or loss of 10° or more of correction, group B had the lowest failure rate (10% vs. 3.2% vs. 10%, p = 0.542). The group A had the highest rate of return to their previous employment (50% vs. 38% vs. 35%, p = 0.265). Conclusions Compared with transpedicular grafting techniques, additional two “augmenting screws” in the fracture vertebra with short-segment instrumentation are sufficient for one-level thoracolumbar burst fracture.

Surgical outcomes in the elderly with degenerative spondylolisthesis: comparative study between patients over 80 years of age and under 80 years—a gender-, diagnosis-, and surgical method-matched two-cohort analyses

BACKGROUND In Taiwan, the current life expectancy of an 80-year-old man is 88.4 years and that of an 80-year-old is woman is 89.8 years. Surgical candidates older than 80 years usually ask surgeons whether it would be safe for them to undergo surgery. PURPOSE The objectives of this study were to report the surgical outcomes of patients with degenerative spondylolisthesis who were older than 80 years and underwent instrumented surgeries and to compare these data with the outcomes of patients aged 65-79 years. STUDY DESIGN/SETTING This is a retrospective study. PATIENT SAMPLE The study included 76 patients. OUTCOME MEASURES The preoperative medical condition was reviewed using the weighted Charlson Comorbidity Index (CCI) and the American Society of Anesthesiologists (ASA) physical status classification. Clinical outcomes were evaluated according to the Oswestry Disability Index (ODI) and the visual analog scale (VAS) for leg and back pain. Plain radiographs were used to assess the fusion status, implant-related complications, and the prevalence of osteoporotic compression fractures (OVFx). MATERIALS AND METHODS The study comprised patients older than 80 years, and the control group comprised patients aged 65-79 years. The two cohorts were matched for gender, main diagnosis, and surgical method. RESULTS In total, 76 patients were included in the study. The study group had 38 patients with a mean age of 82.4 years (80-93 years); the control group also had 38 patients with a mean age of 70.8 years (65-79 years). The study group had a significantly higher ASA classification (2.94 vs. 2.76, p=.040) and CCI score (1.84 vs. 1.13, p=.012). The study group had a higher prevalence of preoperative OVFx (10.5% vs. 2.6%, p=.116) and incidence of new-onset OVFx (13.2% vs. 2.6%, p=.089). The study group had longer operative times (204.6 vs. 179.1 minutes, p=.052) with more blood loss (606.5 vs. 525.8 mL, p=.512), but this finding was not statistically significant. The mean ODI and VAS scores were similar between the two groups. The bone union rate was superior in the control group (81.6% vs. 89.5%, p=.328). CONCLUSIONS Patients older than 80 years have a higher osteoporotic status and comorbidities, which may lead to longer operative times and greater blood loss, with poorer radiographic outcomes. However, the clinical results were not affected. With appropriate patient selection, the age of >80 years is not a negative predictive factor for instrumented surgery for degenerative spondylolisthesis.

Effects of Low-Intensity Pulsed Ultrasound on Spinal Pseudarthrosis Created by Nicotine Administration A Model of Lumbar Posterolateral Pseudarthrosis in Rabbits

Low‐intensity pulsed ultrasound (US) can enhance spinal fusion and fracture healing; however, its effect on spinal pseudarthrosis has not been reported in the literature. We hypothesized that low‐intensity pulsed US could overcome spinal pseudarthrosis created by nicotine administration.