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Objective To evaluate prevalence and prognosis of postoperative coronal imbalance (CIB) and factors related to its onset and spontaneous improvement in patients with Lenke 5C adolescent idiopathic scoliosis who underwent selective thoracolumbar-lumbar fusion. Methods We measured radiographic parameters and evaluated clinical outcomes using the Scoliosis Research Society-22 questionnaire in patients with Lenke 5C adolescent idiopathic scoliosis and a minimum 2-year follow-up. CIB was defined as >2 cm distance between C7 plumb line and central sacral vertical line. We compared parameters between patients with CIB (CIB group) and without CIB (coronal balanced group). Results Inclusion criteria were met by 29 patients (mean age at surgery:17.0 years; average follow-up period: 45.6 months). CIB was found in 10 patients 1 week after surgery (34.5%); this decreased to 6.9% at final follow-up. Comparative analysis indicated significant values as follows: age at surgery (17.5 years vs. 14.7 years, P = 0.005), lumbosacral curve (5.9° vs. 11.2°, P = 0.02), and L5 tilt (−3.6° vs. −8.1°, P = 0.02) in bending film. Greater changes of lowest instrumented vertebra disc angle, which means scoliotic angles between LIV and LIV+1, were significantly associated with spontaneous improvement of CIB (P = 0.04). Clinical outcomes were comparable between the coronal balanced and CIB groups. Conclusions Although CIB was frequently detected in the early postoperative period after selective thoracolumbar-lumbar fusion, it mostly corrected spontaneously. Relatively younger age at surgery and less flexible lumbosacral curve may be related to postoperative CIB, and greater changes of LIV disc angle may be associated with spontaneous improvement of CIB.

Understanding the natural history of the spinopelvic alignment in adolescent idiopathic scoliosis (AIS) is important in developing surgical strategies for patients with adult idiopathic lumbar scoliosis (AdLS). Because it is challenging to follow individuals without any treatments, we sought to estimate its natural history by comparing radiographic characteristics of patients with AIS and AdLS.We included patients with Lenke 5 AIS and patients with AdLS who were diagnosed with Lenke 5 AIS in adolescence. The Cobb angle of the curve and spinopelvic parameters were measured by whole spine radiographs. The AdLS patients were divided into 2 groups according to age50 years (AdLS50) or ≥50 years (AdLS≥50). Radiographic parameters were compared among the AIS, AdLS50, and AdLS≥50 groups. The relationship between age and each parameter was analyzed using nonlinear regression analysis.We analyzed 40 patients with AIS (all female, mean age 16.8 ± 3.2 years) and 35 patients with AdLS (34 female and 1 male, mean age 55.4 ± 12.1 years). Thoracolumbar/lumbar curve and thoracolumbar kyphosis was significantly greater in the AdLS50 group compared with the AIS group, without progression after age 50 years. Lumbar lordosis and pelvic tilt deteriorated linearly with age. AIS and AdLS50 patients maintained sagittal balance, which deteriorated in AdLS≥50 patients.Our results may predict the following natural course of Lenke 5 AIS: (1) progression of scoliotic deformity of thoracolumbar/lumbar curve with increased thoracolumbar kyphosis; (2) subsequent lumbar hypolordosis followed by pelvic retroversion; and (3) sagittal imbalance after failure of compensation.

We investigated the relationship between trunk muscle mass and spinal pathologies by gender. This multicenter cross-sectional study included patients aged ≥ 30 years who visited a spinal outpatient clinic. Trunk and appendicular muscle mass were measured using bioelectrical impedance analysis. The Oswestry Disability Index (ODI), visual analog scale (VAS) score for low back pain, sagittal vertical axis (SVA), and EuroQol 5 Dimension (EQ5D) score were investigated to evaluate spinal pathology. The association between trunk muscle mass and these parameters was analyzed by gender using a non-linear regression model adjusted for patients’ demographics. We investigated the association between age and trunk muscle mass. We included 781 men and 957 women. Trunk muscle mass differed significantly between men and women, although it decreased with age after age 70 in both genders. Lower trunk muscle mass was significantly associated with ODI, SVA, and EQ5D score deterioration in both genders; its association with VAS was significant only in men. Most parameters deteriorated when trunk muscle mass was

OBJECTIVEThe object of this study was to analyze the prevalence of postoperative coronal imbalance (CIB) and related factors in patients with adult lumbar scoliosis.METHODSThis was a retrospective single-center study of data from patients with adult spinal deformity (ASD) who had undergone corrective surgery performed by a single surgeon between 2009 and 2017. The inclusion criteria were as follows: 1) age at surgery > 40 years, 2) Cobb angles of the thoracolumbar/lumbar (TL/L) curve > 40°, 3) upper instrumented vertebra of T9 or T10, 4) lowest instrumented vertebra of L5 or the pelvis, and 5) minimum 2-year follow-up period. Radiographic parameters were measured before surgery, 2 weeks after surgery, and at the latest follow-up. Curve flexibility was also assessed using side bending radiographs. Clinical outcomes were evaluated using the 22-Item Scoliosis Research Society Outcomes Questionnaire (SRS-22) and the SF-36. CIB was considered to have occurred if the C7 plumbline was more than 2.5 cm lateral to the central sacral vertical line (i.e., coronal vertical axis [CVA] > 2.5 cm) at the final follow-up. Parameters between the patients with (CIB group) and without (coronal balance [CB] group) CIB were compared, and factors related to CIB were evaluated.RESULTSFrom among 66 consecutively treated ASD patients, a total of 37 patients (mean age at surgery 66.3 years, average follow-up 63 months) met the study inclusion criteria. CIB was found in 6 patients at the final follow-up (16.2%), and the CVA of all patients in the CIB group shifted to the convex side of the TL/L curve. A comparative analysis between the CB and CIB groups, respectively, at the final follow-up indicated the following factors were related to CIB: lumbosacral (LS) curve, 11.0°/16.5° (p = 0.02); LS correction rate (CR), 61%/47% (p = 0.02); and CR ratio (LS vs TL/L), 0.93/0.67 (p = 0.0002). Regarding clinical outcomes, the satisfaction domain of the SRS-22 (CB 4.4 vs CIB 3.5) showed a significant difference between the CIB and CB groups (p = 0.02), and patients in the CB group tended to score better on the pain domain (CB 4.3 vs CIB 3.7), but the difference was not significant (p = 0.06).CONCLUSIONSPostoperative CIB negatively impacted patients’ HRQOL. An imbalanced correction ratio between the TL/L and LS curves may cause postoperative CIB. Therefore, adequate correction of the LS curve may prevent postoperative CIB.

A 20-year-old man with Noonan syndrome had rigid cervical kyphosis caused by cervical myelopathy and thoracic lordosis caused by pulmonary disfunction. Two-staged corrective surgery, which involved initial posterior spinal fusion (PSF) in T2-L2 followed by PSF in C3-T2, had been performed without any complications. The radiographs before surgery and 2 years after surgery showed that cervical lordosis (C2-7) changed form -56° to -29°, and thoracic kyphosis (T5-12) improved from -49° to 10°.Initial realignment surgery in the caudal lesion should be better for improving global spinal alignment in patients with rigid spinal deformities at different locations.

Recently, an expandable cage equipped with rectangular footplates has been used for anterior vertebral replacement in osteoporotic vertebral fracture (OVF). However, the postoperative changes in global alignment have not been elucidated. The purpose of this study was to evaluate local and global spinal alignment after anterior and posterior spinal fixation (APSF) using an expandable cage in elderly OVF patients. This retrospective multicenter review assessed 54 consecutive patients who underwent APSF for OVF. Clinical outcomes were compared between postoperative sagittal vertical axis (SVA) &gt, 95 mm and ≤95 mm groups to investigate the impact of malalignment. SVA improved by only 18.7 mm (from 111.8 mm to 93.1 mm). VAS score of back pain at final follow-up was significantly higher in patients with SVA &gt, 95 mm than SVA ≤ 95 mm (42.4 vs. 22.6, p = 0.007). Adjacent vertebral fracture after surgery was significantly more frequent in the SVA &gt, 95 mm (37% vs. 11%, p = 0.038). Multiple logistic regression showed significantly increased OR for developing adjacent vertebral fracture (OR = 4.76, 95% CI 1.10–20.58). APSF using the newly developed cage improves local kyphotic angle but not SVA. The main cause for the spinal malalignment after surgery was postoperative development of adjacent vertebral fractures.

Background: Anterior and posterior spinal fixation (APSF) can provide rigid structural anterior column support in patients with osteoporotic vertebral fracture (OVF). A new rectangular footplate designed based on biomechanical studies of endplates provides better resistance to subsidence. However, differences in characteristics exist between the thoracolumbar and lower lumbar spine. The purpose of this study was to evaluate the surgical outcomes following APSF using an expandable cage with rectangular footplates in the thoracolumbar/lumbar region. Methods: Consecutive patients who underwent APSF for OVF at multiple centers were retrospectively reviewed. Clinical and radiographic evaluations were performed by dividing the patients into thoracolumbar (TL, T10–L2) and lumbar (L, L3–L5) groups. Surgical indications were incomplete neurologic deficit or intractable back pain with segmental spinal instability. Surgical outcomes including the Japanese Orthopaedic Association (JOA) score and reoperation rate were compared between TL and L groups. Results: Sixty-nine patients were followed-up for more than 12 months and analyzed. Operative intervention was required for 35 patients in the TL group and 34 patients in the L group. Mean ages in the TL and L groups were 76.5 years and 75.1 years, respectively. Intra-vertebral instability was more frequent in the TL group (p

Study Design Retrospective case series. Purpose To evaluate surgical outcomes and effectiveness of an autogenic rib graft for upper cervical fixation in pediatric patients. Overview of Literature Autogenic bone grafts have long been considered the ‘gold standard’ bone source for posterior cervical fusion in pediatric patients. However, there are some unsolved problems associated with donor-site morbidity and amount of bone grafting. Methods We studied five consecutive pediatric patients who underwent atlantoaxial fixation or occipitocervical fixation (OCF) using an autogenic rib graft with at least 2 years of follow-up (mean age, 9.8 years; mean follow-up period, 73.0 months). Two patients underwent OCF without screw-rod constructs and three patients with screw-rod constructs. Autogenic rib grafts were used in all patients. We evaluated the surgical outcomes including radiographic parameter, bony union, and perioperative complications. Results The atlantoaxial interval (ADI) was corrected from 11.6 to 6.0 mm, and the C1–2 angle was corrected −14.8° to 7.8°. The C2–7 angle was reduced from 31° to 9° spontaneously. Two patients with OCF required revision surgery due to loss of correction. Patients did not experience any complication associated with the donor sites (rib bone grafts). Six months postoperation X-rays clearly showed regeneration of the rib at the donor sites. Bony fusion was achieved in all patients; however, bony fusion occurred more slowly in patients without screw-rod constructs compared with patients with screw-rod constructs. Bone regeneration of the rib was observed in all patients with no complications at the donor site. Conclusions Autogenic rib grafts have advantages of potential bone regeneration, high fusion rate, and low donor-site morbidity. In addition, a screw-rod construct provides better bony fusion in pediatric patients with OCF and atlantoaxial fixation.

A multicenter cross-sectional study. To clarify the relationship of trunk muscle mass with low back pain, spinal sagittal balance, and quality of life. Few reports have investigated the relationship of trunk muscle mass with lumbar spine function and spinal balance, and the clinical significance of trunk muscle mass remains unclear. Patients attending spinal outpatient clinics at 10 different medical institutions were enrolled in this study. Patient demographics, trunk muscle mass and appendicular skeletal muscle mass (ASM) measured by bioelectrical impedance analysis (BIA), body mass index (BMI), Charlson Comorbidity Index (CCI), the Oswestry Disability Index (ODI), visual analog scale (VAS) for low back pain, sagittal vertical axis (SVA), and EuroQol 5 Dimension (EQ5D) score were investigated. Multivariate nonlinear regression analysis was used to investigate the association of trunk muscle mass with the ODI, VAS score, SVA, and EQ5D score. Of 2551 eligible patients, 1738 (mean age 70.2 ± 11.0 years; 781 men and 957 women) were enrolled. Trunk muscle mass was significantly correlated with the ODI, VAS score, SVA, and EQ5D score (P

Introduction: The presence of existing osteoporotic vertebral fracture (OVF) increases the mortality risk. However, the influence of the characteristics of OVF is unclear. This study aimed to investigate the influence of new OVF on patients’ long-term prognosis using our past cohort study. Method: This is an extension study of our cohort study carried out between 2005 and 2007. In the present extension study, of 420 patients, 197 whose contact information was available at the 6-month follow-up were included in the telephone survey in 2018. Five patients refused to participate in the survey, and 82 could not be contacted. Eventually, 110 patients were enrolled. Of the Demographic data, radiological findings, medical history, and clinical outcome were investigated at injury onset and at the 6-month follow-up. A proportional hazard model was used to investigate the risk factors for mortality. Results: Among 110 patients, 33 died. Male sex and low body mass index (BMI 2) were significant risk factors for mortality [hazard ratio (HR) = 6.40, 1.01–40.50; 5.24, 1.44–19.04, respectively]. The history of stroke and liver disease increased the risk of mortality (HR = 13.37, 1.93–92.7; 6.62, 1.15–38.14, respectively). As regards radiological findings, local kyphosis progression per 1° or ≥7° were significant risk factors of mortality (HR = 1.20, 1.06–1.36; 5.38, 1.81–16.03, respectively). Conclusions: A telephone survey at 12 years after the occurrence of OVF analyzed risk factors for mortality and showed that a progression of local kyphosis in fractures between injury onset and 6 months after injury was a risk factor of poor prognosis.

STUDY DESIGN Retrospective cohort study. OBJECTIVE To clarify the poor patient satisfaction after lumbar spinal surgery in elderly patients. SUMMARY OF BACKGROUND DATA As the global population continues to age, it is important to consider the surgical outcome and patient satisfaction in the elderly. No studies have assessed patient satisfaction in elderly patients undergoing surgical treatment and risk factors for poor satisfaction in elderly patients after lumbar spinal surgery. MATERIALS AND METHODS A retrospective multicenter survey was performed in 169 patients aged above 80 years who underwent lumbar spinal surgery. Patients were followed up for at least 1 year after surgery. We assessed patient satisfaction from the results of surgery by using a newly developed patient questionnaire. Patients were assessed by demographic data, surgical procedures, complications, reoperation rate, pain improvement, and risk factors for poor patient satisfaction with surgery for lumbar spinal disease. RESULTS In total, 131 patients (77.5%, G-group) were satisfied and 38 patients (22.5%, P-group) were dissatisfied with surgery. The 2 groups did not differ significantly in baseline characteristics and surgical data. Postoperative visual analog scale score for low back pain and leg pain were significantly higher in the P-group than in the G-group (low back pain: G-group, 1.7±1.9 vs. P-group, 5.2±2.5, P

The purpose of this study was to assess the surgical outcomes of posterior vertebral column resection (PVCR) with short-segment fusion for pediatric patients with congenital kyphoscoliosis (CKS). The medical records of 12 consecutive pediatric patients with CKS due to hemivertebrae located in thoracolumbar and lumbar area that had undergone PVCR and presented for follow-up at a minimum of 2 years were retrospectively reviewed. The mean follow-up period was 56.2 months, and the mean age at the surgery was 9.2 years. We evaluated radiographic parameters using plain radiographs, and evaluated segmental correction using computed tomography imaging. The mean values of the preoperative Cobb angle (cranial curve, main curve, and caudal curve) were 16.0°, 41.3°, and 25.0°, respectively. The main curve was reduced 5.4° after surgery and was maintained at 6.3° at the time of the most recent follow-up. The overall correction rate of main curve was 86.6%. Spontaneous correction rate in the cranial curve and caudal curve were calculated as 55.9 and 80.8%, respectively. The mean segmental scoliosis in the osteotomized segments and fused segments at preoperative/postoperative/final follow-up (FFU) were 40.8°/7.8°/9.2° and 34.3°/3.9°/5.1°, respectively. The mean segmental kyphosis in the osteotomized segments and fused segments at the preoperative/postoperative/FFU were 36.0°/3.8°/4.0° and 27.5°/-1.3°/0.7°, respectively. Our data indicate that PVCR with short-segment fusion for CKS can provide good correction in the main curve and spontaneous correction in the compensatory curves after a minimum 2-year follow-up. Further investigation over the long term is mandatory for pediatric patients.

Study Design Retrospective comparative study. Purpose To compare the incidence of proximal junctional kyphosis (PJK) between transverse process hooks (TPHs) and pedicle screws (PSs) at the upper instrumented vertebrae (UIV) following adult spinal deformity (ASD) surgery. Overview of Literature The choice of UIV implant type may be important for avoiding PJK; however, few comparative clinical studies have evaluated the incidence of PJK according to the type of UIV implant used in ASD surgery. Methods We retrospectively reviewed 39 consecutive patients with ASD (mean age, 67 years; mean follow-up period, 41 months) who underwent corrective surgery between 2009 and 2013. TPH was used in 17 patients and PS in 22 patients. PJK was defined as the presence of a UIV or UIV±1 fracture, or a change in the proximal junctional angle (PJA) of >20°. Data of patients with TPH and PS were compared. Results The TPH group had a PJK incidence of 17.6% compared with 27.3% in the PS group (p =0.47). In the TPH group, PJK was a result of UIV fracture in one patient, UIV−1 fracture in one patient, and ligamentous failure in one patient. In the PS group, six patients developed PJK because of UIV fracture. No differences in radiographic parameters were found between the two groups. After analyzing the PJA data in the patients with PJK, the changes in PJA were significantly higher in the PS group than in the TPH group (19.0°/5.0°, p =0.04). Conclusions Our results show that using TPH as a UIV implant may not prevent PJK; however, using TPH as the UIV anchor may prevent vertebral collapse if cases of UIV fracture. The increased risk of UIV fracture collapse in the PS group may be a result of a higher mechanical load on UIV when using PS.

Introduction: With an aging population, the proportion of patients aged 80 years requiring cervical surgery is increasing. Surgeons are concerned with the high incidence of complications in this population, because “age” itself has been reported as a strong risk factor for complications. However, it is still unknown which factors represent higher risk among these elderly patients. Therefore, this study was conducted to identify the risk factors related to surgical complications specific to elderly patients by analyzing the registry data of patients aged 80 years who underwent cervical surgery. Methods: We retrospectively studied multicenter collected registry data using multivariate analysis. Sixty-six patients aged 80 years who underwent cervical surgery and were followed up for more than one year were included in this study. Preoperative patient demographic data, including comorbidities and postoperative complications, were collected from multicenter registry data. Complications were considered as major if they required invasive intervention, caused prolonged morbidity, or resulted in prolongation of hospital stay. Logistic regression analysis was performed to analyze the risk factors for complications. A p-value of

Study Design: Retrospective study of registry data. Objectives: Aging of society and recent advances in surgical techniques and general anesthesia have increased the demand for spinal surgery in elderly patients. Many complications have been described in elderly patients, but a multicenter study of perioperative complications in spinal surgery in patients aged 80 years or older has not been reported. Therefore, the goal of the study was to analyze complications associated with spine surgery in patients aged 80 years or older with cervical, thoracic, or lumbar lesions. Methods: A multicenter study was performed in patients aged 80 years or older who underwent 262 spinal surgeries at 35 facilities. The frequency and severity of complications were examined for perioperative complications, including intraoperative and postoperative complications, and for major postoperative complications that were potentially life threatening, required reoperation in the perioperative period, or left a permanent injury. Results: Perioperative complications occurred in 75 of the 262 surgeries (29%) and 33 were major complications (13%). In multivariate logistic regression, age over 85 years (hazard ratio [HR] = 1.007, P = 0.025) and estimated blood loss ≥500 g (HR = 3.076, P = .004) were significantly associated with perioperative complications, and an operative time ≥180 min (HR = 2.78, P = .007) was significantly associated with major complications. Conclusions: Elderly patients aged 80 years or older with comorbidities are at higher risk for complications. Increased surgical invasion, and particularly a long operative time, can cause serious complications that may be life threatening. Therefore, careful decisions are required with regard to the surgical indication and procedure in elderly patients.

Study Design:Retrospective database analysis.Objective:Spine surgeries in elderly patients have increased in recent years due to aging of society and recent advances in surgical techniques, and postoperative complications have become more of a concern. Postoperative delirium is a common complication in elderly patients that impairs recovery and increases morbidity and mortality. The objective of the study was to analyze postoperative delirium associated with spine surgery in patients aged 80 years or older with cervical, thoracic, and lumbar lesions.Methods:A retrospective multicenter study was performed in 262 patients 80 years of age or older who underwent spine surgeries at 35 facilities. Postoperative complications, incidence of postoperative delirium, and hazard ratios of patient-specific and surgical risk factors were examined.Results:Postoperative complications occurred in 59 of the 262 spine surgeries (23%). Postoperative delirium was the most frequent complication, occurring in 15 of 262 patients (5.7%), and was significantly associated with hypertension, cerebrovascular disease, cervical lesion surgery, and greater estimated blood loss ( P < .05). In multivariate logistic regression using perioperative factors, cervical lesion surgery (odds ratio = 4.27, P < .05) and estimated blood loss ≥300 mL (odds ratio = 4.52, P < .05) were significantly associated with postoperative delirium.Conclusions:Cervical lesion surgery and greater blood loss were perioperative risk factors for delirium in extremely elderly patients after spine surgery. Hypertension and cerebrovascular disease were significant risk factors for postoperative delirium, and careful management is required for patients with such risk factors.

Study Design:Prospective cohort study.Objective:Microsurgical bilateral decompression via a unilateral approach (MBDU), a minimally invasive surgical (MIS) decompression method, has been performed for numerous degenerative lumbar diseases, including degenerative lumbar scoliosis (DLS) or degenerative spondylolisthesis (DS), at our institution. In this study, we evaluated the appropriateness of MBDU for DLS or DS patients.Methods:A total of 207 patients treated by MBDU were included (88 women and 119 men; mean age, 70 [40-86] years). Thirty-seven cases were diagnosed as DLS (group A), 51 as DS (group B), and 119 as lumbar canal stenosis (group C). Patient clinical status assessed by JOA score was evaluated preoperatively and 2 years postoperatively. We evaluated the prevalence of cases that required reoperation among the groups and the radiographic risk factors related to reoperation.Results:There was no significant difference in recovery ratios of JOA scores among the groups. Reoperation after MBDU was needed in 13 cases (6.3%); the revision rate did not significantly differ among the groups. Reoperation was associated with poor clinical status, low visual analog scale score for low back pain, and low SF-36 mental component summary score. Reoperation was significantly associated with preoperative scoliotic disc wedging with Cobb’s angle ≥3° in L4-5 (odds ratio = 9.88) and lateral listhesis (odds ratio = 5.22 [total], 12.9 [L4-5]).Conclusions:When we are careful to indicate decompression for patients with these risk factors related to reoperation, MIS decompression alone can successfully improve DLS patients with a Cobb’s angle of ≤20° or DS patients.

Study Design: Retrospective clinical study. Objective: We evaluated the relationship between cervical sagittal alignment parameters and clinical status in patients with cervical myelopathy and analyzed the effect of cervical sagittal balance on cervical laminoplasty. Methods: Patients with cervical myelopathy (n = 110) who underwent laminoplasty were included in this study. The relationship between cervical sagittal alignment parameters and clinical status was evaluated. The changes in radiographic cervical sagittal parameters and clinical status 2 years after surgery were compared between patients with preoperative C2-7 SVA ≥35 mm (group A) and those with preoperative C2-7 SVA Results: Preoperatively, C2-7 SVA had no correlation with defined health-related quality of life evaluation scores. At 2-year follow-up, the improvement in SF-36 physical component summary was significantly lower in group A than in group B. The postoperative change of C2-7 SVA did not significantly differ in 2 groups. Patients in group A maintained cervical regional balance after laminoplasty but experienced extensive postoperative neck pain. Conclusions: Our patients with a C2-7 SVA of ≥35 mm maintained cervical regional balance after laminoplasty and their improvement in myelopathy was equivalent to that in patients with a C2-7 SVA of

Study Design: A retrospective case control study.Purpose: The purpose of this study was to compare the surgical outcomes of multilevel lateral lumbar interbody fusion (LIF) and multilevel posterior lumbar interbody fusion (PLIF) in the surgical treatment of adult spinal deformity (ASD) and to evaluate the sagittal plane correction by combining LIF with posterior-column osteotomy (PCO).Overview of Literature: The surgical outcomes between multilevel LIF and multilevel PLIF in ASD patients remain unclear.Methods: We retrospectively reviewed 31 ASD patients who underwent multilevel LIF combined with PCO (LIF group, n=14) or multilevel PLIF (PLIF group, n=17) and with a minimum 2-year follow-up. In the comparison between LIF and PLIF groups, their mean age at surgery was 69.4 vs. 61.8 years while the mean follow-up period was 29.2 vs. 59.3 months. We evaluated the transition of pelvic incidence–lumbar lordosis (PI–LL) and disc angle (DA) in the LIF group, in fulcrum backward bending (FBB), after LIF and after posterior spinal fusion (PSF) with PCO. The spinopelvic radiographic parameters were compared between LIF and PLIF groups.Results: Compared with the PLIF group, the LIF group had less blood loss and comparable surgical outcomes with respect to radiographic data, health-related quality of life scores and surgical time. In the LIF group, the mean DA and PI–LL were unchanged after LIF (DA, 5.8°; PI–LL, 15°) compared with the values using FBB (DA, 4.3°; PI–LL, 15°) and improved significantly after PSF with PCO (DA, 8.1°; PI–LL, 0°).Conclusions: In the surgical treatment of ASD, multilevel LIF is less invasive than multilevel PLIF and combination of LIF and PCO would be necessary for optimal sagittal correction in patients with rigid deformity.

Study Design Retrospective study. Objective To compare clinical outcomes, radiographic evaluations including bony union rate and incidence of osteoporotic vertebral fractures (OVFxs), and perioperative complications following posterior lumbar interbody fusion (PLIF) between patients ≥80 years of age and those Methods Ninety-six patients ≥70 years old who underwent PLIF were reviewed. We divided the patients into the two age groups, ≥80 group ( n = 19) and Results The JOA score improved 47.6% in the ≥80 group and 49.1% in the Conclusions The present study indicated that surgical outcomes of PLIF in patients ≥80 years were comparable to those

Background The degenerative lumbar scoliosis (DLS) patients who mainly complained about neurogenic claudication due to spinal canal stenosis are well-indicated for short segment fusion (SSF) at the affecting levels. However, it is unclear whether we should consider global sagittal balance or not. The aim of this study was to evaluate the impact of sagittal balance on the surgical outcomes of degenerative lumbar scoliosis (DLS) patients who underwent SSF. Methods We retrospectively reviewed 70 DLS patients who underwent SSF (less than 3 levels) and could be followed for at least 2 years. The PI-LL, PT, SVA, and T1 pelvic angle (TPA) were measured using standing whole spine X-rays preoperatively (PreO) and at final follow-up (FFU). Surgical outcomes were assessed with the improvement in Japanese Orthopaedic Association score (JOAs) for low back pain (LBP), and the level of LBP was measured using the visual analogue scale (LBP-VAS). We analysed the relationships between the radiographic parameters and the surgical outcomes. Results We divided the patients into the three groups (poor/fair/good) based on the JOAs. The analysis with the Jonckheere-Terpstra trend test indicated that the following radiographic parameters had a significant trend with surgical outcomes in each group: (poor/fair/good; p value); PreO PI-LL (26/20/17°; P = 0.04), SVA (46/75/35.5 mm; P = 0.02), TPA (28/27/23°; p = 0.04), FFU PI-LL (33/25/8.5°; P = 0.004), SVA (93/90.5/32.5 mm; P = 0.001), and TPA (33/29/25°; P = 0.007). Additionally, LBP-VAS had a significant correlation between the three groups at final follow-up (P = 0.004). There were significant correlations between improvement in JOAs and PI-LL, SVA, and TPA both PreO and at FFU (P Conclusions Sagittal spinal imbalance and spinopelvic malalignment significantly impact the surgical outcomes of SSF for DLS. Preoperative evaluation of spinopelvic alignment and sagittal balance is of critical importance when SSF are performed for DLS patients.

In this prospective multicenter study of osteoporotic vertebral fractures (OVFs), delayed union of OVF at 6-month follow-up caused prolonged pain, QOL impairment, ADL impairment, cognitive status deterioration, and vertebral collapse progression. Delayed union following osteoporotic vertebral fracture displayed as an intravertebral cleft on plain X-rays was reported to be a factor for prolonged severe pain. However, the difference of clinical course between bone union and delayed union cases still remains unclear. The purpose of this study was to identify how OVF delayed union following conventional conservative treatment influences the clinical course with a prospective multicenter study. A total of 324 OVF patients from 25 institutes in Osaka, Japan, were included in the study. At the 6-month follow-up after initial visit to each institute, the patients were classified into bone union and delayed union groups based on plain X-ray findings. The outcome assessments included a VAS for back pain, SF-36 for quality of life (QOL), severity of bed-ridden state for activities of daily living (ADL), MMSE for cognitive functions, and degree of vertebral collapse on plain X-rays. Overall, 280 patients were included into the union group and 44 into the delayed union group. The VAS score at 6 months was significantly worse in the delayed union group (p = 0.01). The scores for the SF-36 scales of physical functioning and bodily pain at 6 months were significantly lower in the delayed union group (p = 0.019, p = 0.01, respectively). The percentage of nearly or completely bed-ridden patients was significantly higher in the delayed union group. The percentage of newly developed cognitive impairment was significantly higher in the delayed union group (p = 0.02). Progression of vertebral collapse during the 6-month follow-up was more pronounced in the delayed union group (p

Background Osteoporotic vertebral fractures (OVFs) are the most common cause of intractable back pain and reduced activities of daily living (ADL), which may affect cognitive function. However, no previous studies have reported a change in cognitive function after OVFs. The purpose was to reveal cognitive function changes after OVFs and investigate the risk factors for cognitive decline. Methods Consecutive patients with symptomatic OVFs were enrolled in a prospective multicenter cohort study. The inclusion criteria were age >65 years, diagnosis of acute or subacute OVF, and back pain onset within 2 months prior to presentation. Cognitive function was assessed with the mini-mental state examination. Medical history, radiological findings, and ADL were investigated as risk factors for cognitive decline. Results We recruited a sample of 339 patients (58 men and 281 women) who met the inclusion criteria. Patients underwent examinations and completed questionnaires at both the time of enrollment and at 6-month follow-up. At 6-month follow-up, cognitive decline was observed in 26 (7.7%) patients. Medical history, including comorbidities and sports activities, did not affect odds ratios (ORs). However, elevated ORs were associated with delayed union (OR: 4.67, 95% Confidence interval: 1.22–17.87). In addition, significantly increased ORs were associated with reduced ADL at 6-month follow-up. Conclusions The current results revealed the incidence of cognitive decline after the onset of OVF. Delayed union and reduced ADL at 6-month follow-up were associated with cognitive decline. Patients with cognitive decline experienced significantly reduced quality of life. These results highlight the importance of preventing cognitive impairment in patients with symptomatic OVF. Physical treatment or early surgical treatment may provide appropriate options, particularly for patients with suspected delayed union.

Study design Prospective multicenter study. Objective To examine whether initial conservative treatment interventions for osteoporotic vertebral fractures (OVF) influence patient outcomes. Summary of background data OVFs have been described as stable spinal injuries and, in most cases, are managed well with conservative treatment. However, systematic treatments for OVF have not been clearly established. Methods A total of 362 patients with OVF (59 males and 303 females; mean age, 76.3 yr) from 25 institutes were enrolled in this clinical study. All the patients were treated conservatively without any surgical interventions. The patient outcomes were evaluated 6 months after the fractures on the basis of Short Form-36 (SF-36) physical component summary (PCS) and mental component summary (MCS), activities of daily living (the Japanese long-term care insurance system), back pain (visual analogue scale), cognitive status (mini-mental state examination), and vertebral collapse, which were used as response variables. Furthermore, brace type, hospitalization, bisphosphonates after injury, and painkillers after injury were explanatory variables for the treatment interventions. To evaluate the independent effects of treatment interventions on patient outcomes, we performed multivariate logistic regression analyses and obtained odds ratios that were adjusted for the potential confounding effects of age, sex, level of fracture, presence of middle-column injury, pain visual analogue scale at enrollment, mini-mental state examination score at enrollment, and previous use of steroids. Results There was no significant difference for treatment intervention factors including brace type, hospitalization, bisphosphonates after injury, and painkillers after injury. For adjusting factors, the presence of middle-column injury was significantly associated with SF-36 PCS ≤ 40, reduced activities of daily living, prolonged back pain, and vertebral collapse. Female sex and advanced age were associated with SF-36 PCS ≤ 40. Low mini-mental state examination scores at enrollment were associated with SF-36 PCS ≤ 40 and reduced activities of daily living. The previous use of steroids was associated with SF-36 MCS ≤ 40, prolonged back pain, and vertebral collapse. No other examined variables were significant risk factors for patient outcomes. Conclusion These results showed that treatment intervention factors did not affect patient outcomes 6 months after OVF. Middle-column injury was a significant risk factor for both clinical and radiological outcomes. In the future, establishing systematic treatments for cases with middle-column injuries is needed. Level of evidence 2.

STUDY DESIGN Retrospective study. OBJECTIVE To analyze the clinical outcomes of anterior and posterior spinal fusion (APSF) using a fibular strut autograft (FSAG) and to investigate the morphological changes in the reconstructed spinal column of dystrophic deformities in neurofibromatosis (NF)-1. SUMMARY OF BACKGROUND DATA APSF is desirable for dystrophic deformities in NF-1 with more than 50° of dystrophic kyphosis. There are few reports regarding the clinical outcomes of APSF in which the morphological changes over time of the anterior strut graft have been investigated. METHODS The clinical and radiographic outcomes of APSF with FSAG were investigated in 10 consecutive patients with dystrophic deformity in NF-1. For qualitative and quantitative analyses, the chronological changes in the FSAG configuration, length, and diameter were evaluated. RESULTS The mean follow-up period was 9 years, 9 months (range, 1-30 years). Graft bone erosion and postoperative curve progression were not observed in any patient. In quantitative analyses of the anterior strut, the mean ratio of the latest and immediately postoperative FSAG lengths was 0.98 (0.93-1.09). The mean central/peripheral ratios of the FSAG diameter (central portion/[upper end + lower end]/2) were 1.02 (0.92-1.10) immediately after surgery, and 1.01 (0.92-1.07) at the latest follow-up, with no significant change between these 2 time points (P = 0.937). The mean preoperative cross-sectional area of the apical vertebral body and its mean virtual cross-sectional area at the final follow-up were 3.80 (1.83-5.43) and 4.87 (2.46-7.00) cm(2), respectively, with a significant difference between these 2 parameters (P = 0.0078). The mean final/preoperative ratio was 1.31 (1.10-1.43). CONCLUSION APSF with FSAG for dystrophic deformity in NF-1 successfully reconstructed a reliable spinal column with a rich bone stock. The FSAG and surrounding vertebral bodies were free from postoperative erosion due to dystrophic changes and maintained their stability for a long time.

The purpose of this study was to assess the clinical results of posterior corrective surgery using a multilevel transforaminal lumbar interbody fusion (TLIF) with a rod rotation (RR) and to evaluate the segmental corrective effect of a TLIF using CT imaging. The medical records of 15 consecutive patients with degenerative lumbar kyphoscoliosis (DLKS) who had undergone posterior spinal corrective surgery using a multilevel TLIF with an RR technique and who had a minimum follow-up of 2 years were retrospectively reviewed. Radiographic parameters were evaluated using plain radiographs, and segmental correction was evaluated using CT imaging. Clinical outcomes were evaluated with the Scoliosis Research Society Patient Questionnaire-22 (SRS-22) and the SF-36. The mean follow-up period was 46.7 months, and the mean age at the time of surgery was 60.7 years. The mean total SRS-22 score was 2.9 before surgery and significantly improved to 4.0 at the latest follow-up. The physical functioning, role functioning (physical), and social functioning subcategories of the SF-36 were generally improved at the latest follow-up, although the changes in these scores were not statistically significant. The bodily pain, vitality, and mental health subcategories were significantly improved at the latest follow-up (p < 0.05). Three complications occurred in 3 patients (20%). The Cobb angle of the lumbar curve was reduced to 20.3° after surgery. The overall correction rate was 66.4%. The pelvic incidence–lumbar lordosis (preoperative/postoperative = 31.5°/4.3°), pelvic tilt (29.2°/18.9°), and sagittal vertical axis (78.3/27.6 mm) were improved after surgery and remained so throughout the follow-up. Computed tomography image analysis suggested that a 1-level TLIF can result in 10.9° of scoliosis correction and 6.8° of lordosis. Posterior corrective surgery using a multilevel TLIF with an RR on patients with DLKS can provide effective correction in the coronal plane but allows only limited sagittal correction.

Background Hybrid constructs have been widely used to surgically correct thoracic adolescent idiopathic scoliosis (AIS). To enhance the correction obtained with hybrid constructs, we perform concave rib head resection and convex costovertebral release as posterior release procedures. The objective of the study was to evaluate coronal and sagittal curve correction in patients with adolescent idiopathic scoliosis (AIS) treated with hybrid constructs combined with concave rib head resection and convex transverse process resection as posterior release procedures. Methods The records of 24 patients with Lenke type 1 or 2 AIS treated with hybrid constructs combined with posterior release procedures were retrospectively reviewed. The mean age at surgery was 14.3 years. The mean follow-up period was 33.0 months (range, 24–60 months). Radiographs were evaluated before surgery, immediately postoperatively, and at latest follow-up. Results The average preoperative Cobb angle of the main thoracic (MT) curve was 58.1 ± 12.6° (range, 45–88°). The MT curve was corrected to 12.8 ± 9.0° (range, 0–38°) immediately after surgery. At the latest follow-up, the average Cobb angle was 13.6 ± 9.9° (range, 0–44°; correction, 77.5 ± 14.0%). The average loss of coronal correction was 0.8°. The average preoperative flexibility of the MT curve was 54.6 ± 17.4%. The average Cincinnati correction index was 1.53 ± 0.48 at the latest follow-up. The average preoperative thoracic kyphosis (TK) was 13.7 ± 12.0° (range, −12–34°). Immediately after surgery, TK was corrected to 18.6 ± 5.9° (range, 10–29°). At the latest follow-up, TK measured 18.1 ± 6.5° (range, 6–32°). Conclusions Hybrid instrumentation combined with concave rib head resection and convex transverse process resection as posterior release procedures achieved satisfactory coronal and sagittal curve correction with little loss of correction at 2-year follow-up.

Study design Prospective cohort study. Objective To elucidate the prognostic factors indicating reduced activities of daily living (ADL) at the time of the 6-month follow-up after osteoporotic vertebral fracture (OVF). Summary of background data OVF has severe effects on ADL and quality of life (QOL) in elderly patients and leads to long-term deteriorations in physical condition. Many patients recover ADL with acceleration of bony union and spinal stability, but some experience impaired ADL even months after fracture. Identifying factors predicting reduced ADL after OVF may prove valuable. Methods Subjects in this prospective study comprised 310 OVF patients from 25 institutes. All patients were treated conservatively without surgery. Pain, ADL, QOL, and other factors were evaluated on enrollment and at 6 months. ADL were evaluated using the criteria of the Japanese long-term care insurance system to evaluate the degree of independence. We defined reduced ADL as a reduction of at least single grade at 6 months after fracture and investigated factors predicting reduced ADL after OVF, using uni- and multivariate regression analysis. Results ADL were reduced at 6 months after OVF in 66 of 310 patients (21.3%). In univariate analysis, age more than 75 years (P = 0.044), female sex (P = 0.041), 2 or more previous spine fractures (P = 0.009), presence of middle column injury (P = 0.021), and lack of regular exercise before fracture (P = 0.001) were significantly associated with reduced ADL. In multivariate analysis, presence of middle column injury (odds ratio [OR], 2.26; P = 0.022) and lack of regular exercise before fracture (OR, 2.49; P = 0.030) were significantly associated with reduced ADL. Conclusion These results identified presence of middle column injury of the vertebral body and lack of regular exercise before fracture as prognostic factors for reduced ADL. With clarification and validation, these risk factors may provide crucial tools for determining subsequent OVF treatments. Patients showing these prognostic factors should be observed carefully and treated with more intensive treatment options.

Object The authors compared the clinical outcomes of microscopic bilateral decompression via a unilateral approach (MBDU) for the treatment of degenerative lumbar scoliosis (DLS) and for lumbar canal stenosis (LCS) without instability. The authors also compared postoperative spinal instability in terms of different approach sides (concave or convex) following the procedure. Methods The authors retrospectively reviewed data obtained in 50 consecutive patients (25 in the DLS group and 25 in the LCS group) who underwent MBDU; the minimum follow-up period was 2 years. Patients with DLS were divided into 2 subgroups according to the surgical approach side: a concave group (23 segment) and a convex group (17 segments). The Japanese Orthopaedic Association Scale scores for the assessment of low-back pain were evaluated before surgery and at final follow-up. The Japanese Orthopaedic Association Scale scores and recovery rates were compared between the DLS and LCS groups, and between the convex and concave groups. Cobb angle and scoliotic wedging angle (SWA) were evaluated on standing radiographs before surgery and at final follow-up. Facet joint preservation (the percentage of preservation) was assessed on pre- and postoperative CT scans, compared between the LCS and DLS groups, and compared between the concave and convex groups. The influence of approach side on postoperative progression of segmental instability was also examined in the DLS group. Results The mean recovery rate was 58.7% in the DLS and 62.0% in the LCS group. The mean recovery rate was 58.6% in the convex group and 60.6% in the concave group. There were no significant differences in recovery rates between the LCS and DLS groups, or between the DLS subgroups. The mean Cobb angles in the DLS group were significantly increased from 12.7° preoperatively to 14.1° postoperatively (p < 0.05), and mean preoperative SWAs increased significantly from 6.2° at L3–4 and 4.1° at L4–5 preoperatively to 7.4° and 4.9°, respectively, at final follow-up (p < 0.05). There was no significant difference in percentage of preservation between the DLS and LCS groups. The mean percentages of preservation on the approach side in the DLS group at L3–4 and L4–5 were 89.0% and 83.1% in the convex group, and those in the concave group were 67.3% and 77.6%, respectively. The percentage of preservation at L3–4 was significantly higher in the convex than the concave group. The mean SWA had increased in the concave group (p = 0.01) but not the convex group (p = 0.15) at final follow-up. Conclusions The MBDU can reduce postoperative segmental spinal instability and achieve good postoperative clinical outcomes in patients with DLS. The convex approach provides surgeons with good visibility and improves preservation of facet joints.

Background context Spontaneous spinal epidural hematoma (SSEH) is a very rare condition, so there were few studies assessing the management criteria of SSEH. Purpose To assess the differential diagnosis and clinical results of treatment for SSEH. Study design A retrospective chart and radiograph review of the patients with SSEH. Patient sample Seven consecutive patients with SSEH who were treated in our institute. Outcome measures Differential diagnosis, severity of the paresis, and treatment selection were assessed preoperatively and postoperatively. Methods We assessed the relationship between the following parameters and clinical results: (1) the initial symptoms, (2) imaging diagnosis of magnetic resonance imaging (MRI), (3) treatment selection (conservative or surgical treatment), (4) the interval of surgery, and (5) the severity of paresis using ASIA impairment scale (AIS) grading. Results In all patients, the symptoms at onset were severe neck and back pain. MRI showed isointensity to the spinal cord in the T1-weighted view and iso- or high intensity in the T2-weighted view. A solid pattern in MRI was shown in 4 patients, and a mosaic pattern was shown in 3 patients. Decompression was performed in five cases, and spontaneous recovery appeared in two cases. The mean interval time for operation was 29.8 hours. The severity of paresis was grade B in 3 cases and grade C in 4 cases at onset. These cases recovered to become grade E in 3 cases and grade D in 4 cases. Neurological deficits were present in two patients with conservative therapy and in two patients with a long interval for operation. Conclusions Precise diagnosis without delay and rapid surgical treatment are essential for the management of SSEH.

Primary processes of photoelectron transfer reactions of highly twisted 1-mesityl- ( 1a ), 1-(2,5-dimethoxyphenyl)- ( 1b ), and 1-(2,3,5,6-tetramethoxyphenyl)- 2,4,6-triphenylpyridinium ( 1c ) tetrafluoroborates in butyronitrile were investigated. The charge-shift states were observed in all cases. Irradiation of 1a generated the charge-shift state (360, 475, and 550 nm), which was converted with a lifetime of 21 ns into the long-lived triplet state ( τ = 2.2 μs) localized on the pyridinium moiety. On the other hand, compounds 1b and 1c generated the charge-shift states ( λ max = 440 and 540 and λ max = ca. 550 nm as a broad absorption) of short lifetimes, 35 and 16 ps, respectively, decaying exclusively to the singlet ground states.

A recombinant BMP-2-retaining putty-form implant in combination with a hip prosthesis was used to reconstruct a canine hip joint with defects similar to those encountered in revision total hip arthroplasty (THA). The bone defects were made by resecting the medial half of the proximal femur and the superior acetabular bone with inner iliac wall perforation in 10 dogs. In five dogs, hip prostheses were implanted with the putty material consisting of a synthetic polymer (poly D,L-lactic acid-polyethylene glycol block copolymer), β-tricalcium phosphate powder, and recombinant human BMP-2 in each defect (BMP/Polymer/TCP group). In the remaining five dogs, the same material without rhBMP-2 (control group) was implanted. In the BMP/Polymer/TCP group, new radiopaque shadows began to appear 4 weeks after surgery at the defects around the hip prostheses on both the femoral and acetabular sides. At 12 weeks, the defects were completely filled with new bone in contact with the prosthesis. On histology, the rhBMP-2/Polymer/β-TCP composite putty implants had been completely resorbed and replaced by new bone. Repair of the bone defects was not seen in the control group. The ability of this material to restore bone effectively eliminates the dependency on bone grafts of autogeneic or allogeneic origin for revision hip arthroplasty and thus opens up a potential new treatment approach in hip cases requiring this type of surgery. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1042–1051, 2007

Background In maxillofacial, spinal, and orthopedic surgery, bony ribs have been used as a source of donor bone. The resultant defects are not usually repaired, despite the pain or cosmetic morbidity experienced by the patient. The authors evaluated the efficacy of an osteoconductive beta-tricalcium phosphate and the contribution of the periosteum in rib bone regeneration. Methods Two 8-cm-long intercalated rib defects were generated in each of 30 beagle dogs. In the first group (n = 15), one defect was implanted with 16 small, short, porous beta-tricalcium phosphate cylinders that were connected with a titanium wire, and the other defect was left untreated. In the remaining 15 dogs, the periosteum was devitalized by ethanol, and then the same surgical procedures were performed. Each group was subdivided into three groups (n = 5), and the animals were euthanized at 3, 6, and 12 weeks. Bone regeneration was assessed radiologically, histologically, and mechanically. Results In the defect implanted with beta-tricalcium phosphate on intact periosteum, newly formed bone was present on and in the beta-tricalcium phosphate cylinders and bridged both ends of the resected ribs at 12 weeks, with replacement of beta-tricalcium phosphate by new bone. Mechanical testing of these ribs revealed that they had 70 percent of the strength of normal ribs when compared in a bending stress test at 12 weeks after surgery. No regenerative bone bridging the rib defects was seen in the ethanol-devitalized or untreated groups. Conclusions Porous beta-tricalcium phosphate cylinders placed in tandem on the intact periosteum might be useful for the repair of rib bone donated at surgery, presenting a new and unique method for regenerating rib defects.

A new method to repair rib defects with biomaterials containing recombinant human bone morphogenetic protein-2 (rhBMP-2) is presented in this report. We had reported previously the successful regeneration of bony rib defects by placing a short chain of small beta-tricalcium phosphate (beta-TCP) cylinders on the intact periosteum. The multi-cylinder implants were ineffective in promoting rib repair when the periosteum was absent. By adding rhBMP-2 to the beta-TCP cylinders, we were able to promote rib bone regeneration in the presence or absence of the periosteum. The osteogenic capacity of the rhBMP-2/beta-TCP composite implant and the time required to complete regeneration were evaluated in a canine model. An 8cm long section of rib bone, including the periosteum, was removed and replaced with a chain of the rhBMP-2/beta-TCP cylinders. At 6 weeks after implantation, the ribs were restored to their original configuration and mechanical strength. The multi-cylinder beta-TCP implants were degraded and replaced by new bone in 12 weeks. This new degradable bone-inducing implant material has significant clinical potential for rib repair.

To improve the efficacy of a block copolymer of poly-d, l-lactic acid with randomly inserted p-dioxanone and polyethylene glycol (PLA-DX-PEG) as a drug delivery system for recombinant human bone morphogenetic proteins (rhBMPs), we examined the relationship between the volume of PLA-DX-PEG, the dose of rhBMP-2 and osteoinduction in a mouse model of ectopic bone formation. In a series of studies, we compared the size and bone mineral content (BMC) of ectopically induced bone by PLA-DX-PEG and collagen sponges carrying different quantities of rhBMP (0, 1, 2, 5, 10, 20 microg). An additional experiment was designed to investigate how a range of PLA-DX-PEG polymer volumes (15, 30, 60, 90 mg) with a fixed rhBMP concentration (0.01 wt%), altered the size and BMC of the induced ossicle. The influence of polymer volume was also examined in a further experiment wherein a fixed amount of rhBMP was placed in a range of PLA-DX-PEG copolymer volumes to give different concentrations of the protein per implant (0.02-0.0017 wt%). The results indicate that the bone yields were linearly dependent on the dose of rhBMP and also were proportional to the polymer volume above the minimal concentration of rhBMP-2 (0.0017 wt% in this series). The optimal concentration of rhBMP-2 in PLA-DX-PEG was 0.003 wt% in mice. The data provide important insights into the fabrication of implants that provide efficacious delivery of rhBMP-2 using the lowest possible dose of this expensive osteoinductive protein. This information will be of value for the clinical use of BMPs.

Calbindin-D28K (Ca-D28K) is a calcium-binding protein. In the kidney, Ca-D28K is present in the distal nephron, but not in the proximal nephron. This site-specific distribution in the kidney indicates that Ca-D28K is a potential marker for the differentiation of the distal nephron. In this study, we have examined the expression of Ca-D28K in 25 sporadic cases of chicken nephroblastomas. All cases of nephroblastomas were composed of atypical tubular structures, blastemal cells, and fibrous stroma in varying degrees of differentiation. Immunohistochemically in all nephroblastoma specimens, Ca-D28K was expressed in the epithelial cells of the subsets of tubular structures, but not in the blastema or the stroma. These results suggested that the tubuli in the nephroblastomas are able to differentiate into the phenotype of distal nephrons. Furthermore, Ca-D28K might develop as a novel diagnostic marker for nephroblastomas because this molecule is reported to be completely negative in other renal tumors, including renal cell carcinoma, chromophobe carcinomas, and oncocytoma.

To produce an osteogenic and bacteriocidal biomaterial for the treatment of infected nonunions or bone defects, a synthetic degradable block copolymer of poly-D,L-lactic acid segments with randomly inserted p-dioxanone and polyethylene glycol (PLA-DX-PEG) segments was mixed with recombinant human BMP-2 (rhBMP-2) and antibiotics at high concentration. We then examined the in vitro elution profile of an antibiotic (teicoplanin) from the polymer, the effects of antibiotics on the bone-inducing capacity of rhBMP-2 or on ectopic new bone formation induced by the rhBMP, and the ability of the polymer to repair bone in a rat cranial defect model. Approximately 40% of teicoplanin was released within the first 24 h, with the remaining amount released steadily over 21 days with no loss of antibacterial activity. The polymer had disappeared by degradation in the phosphate buffered saline (pH 7.4) at the end of the incubation period. The in vivo performance of pellets with antibiotics and rhBMP-2 revealed no significant change in bone yield within the ossicles after 3 weeks. Also, antibiotics had no inhibitory effect on the ability of rhBMP2 to repair cranial defects. Indeed, when the defect was filled by a polymer disc loaded with rhBMP-2 with or without teicoplanin, the defect was repaired by new bone, and normal anatomy was restored within 6 weeks. In conclusion, the PLA/DX/PEG polymer appears to work as effectively for antibiotics as it does for rhBMP-2. Additionally, the biological activity of rhBMP-2 was retained irrespective of the presence of antibiotics.

Study design An experimental animal study to achieve posterolateral intertransverse process spine fusion with recombinant bone morphogenetic protein in combination with a new delivery system. Objective To evaluate the efficacy of a new synthetic biodegradable bone-inducing material containing recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone-graft substitute for posterolateral intertransverse process fusion in a rabbit model. Summary of background data rhBMP-2, a powerful bone-inducing cytokine, has been used as a bone graft substitute in combination with animal-derived collagen to achieve spinal fusion in animal models. However, the minimum dose of rhBMP-2 required to obtain solid posterolateral intertransverse process fusion was high on the basis of previous reports (>100 microg in rabbit models). To improve the efficacy, performance of rhBMP-2, and the safety of the delivery system for this protein, a more sophisticated system is required. Methods To fabricate one implant for one-side L4-L5 intertransverse process fusion, beta-tricalcium phosphate (beta-TCP) powder (300 microg), a polymer gel (PLA-DX-PEG block copolymer; 300 microg) and rhBMP-2 (7.5, 15, or 30 microg) were mixed and manually shaped to resemble a rod. Through a posterolateral approach, two implants were placed on both sides (1 per side) by surgery so as to bridge the transverse processes of adult New Zealand white rabbits (n = 27). In control animals, implants without rhBMP or autogenous cortico-cancellous bone chips from the iliaccrest were placed in a similar location. The lumbar vertebrae were recovered 6 weeks after surgery. The posterolateral fusion was examined by manual palpation, radiography, biomechanical testing, and histology. Results Rabbits that received 15 or 30 microg of rhBMP-2 showed consistent fusion. However, solid fusion was seen in 2 of 5 rabbits with autografting and rabbits that received 7.5 microg of rhBMP-2. Fusion was not observed in the rabbits that did not receive rhBMP-2. Conclusions Consistent spinal fusion was obtained by implanting a biodegradable bone-inducing implant composed of beta-TCP, PLA-DX-PEG, and rhBMP-2 within a period of 6 weeks. The rhBMP-2 doses required for the spinal fusion were significantly lower than those reported previously.