Chung Ss

Osteoconduction at porous hydroxyapatite with various pore configurations

To assess the histological response and the reinforcing effects of bone ingrowth within porous hydroxyapatite (HA) implants depending on pore geometry, four kinds of cylindrical-type with parallel linear pores phi50, 100, 300, 500 microm), one kind of sponge-type with irregular interconnecting pores (phi250 microm) and one cross-type with crossing linear pores (phi100 x 120 microm) of porous HA were prepared. Eighty-four rabbits were divided into six groups, and a 5 x 5 x 7 mm sized porous HA block was inserted through the medial cortical window of the proximal tibia. Histomorphological changes were examined using light and scanning electron microscopy. A biomechanical compression test was performed using material test machines. After implantation, the implants showed different histological changes depending on pore geometry. Active osteoconduction was also found in the phi50 microm sized cylindrical-type porous HA. Evidence of remodeling of new bone and bone marrow formation within porous HA was found in the larger cylindrical-types (phi300, 500 microm), and the sponge- and cross-types. The biomechanical test showed that the ultimate compressive strength increased significantly in the phi300 microm sized cylindrical-type, and in the sponge- and cross-types eight weeks after implantation. Porous HA with cylindrical pores could be a useful graft material due to its strength, osteoconductivity and the ease with which its pore geometry can be controlled.

Treatment recommendations for idiopathic scoliosis: an assessment of the Lenke classification.

Objective. To determine the usefulness of the treatment recommendation criteria based on the Lenke classification for treatment of idiopathic scoliosis. Design. A retrospective radiographic review of 183 patients who underwent anterior and/or posterior fusion for the treatment of idiopathic scoliosis. Summary of Background Data. Recent studies have proven that the Lenke system is relatively efficient and consistent in classifying scoliosis curves. However, the recommendations regarding fusion level have yet to be established as reliable. Materials and Methods. One hundred eighty-three patients with idiopathic scoliosis and with a minimum follow-up period of 24 months were included in the study and classified according to the Lenke system. Among these patients, 135 patients were treated with fusion and instrumentation in accordance with the Lenke classification system and are described as Group I. The 48 patients whose treatments were not based on the Lenke system constitute Group II. These two groups were compared in regard to the correction of the Cobb angle and the trunk shift after surgery in order to establish the effectiveness and reliability of the treatment recommendations based on the Lenke classification system. Results. Type 1 primary thoracic curve: there was no difference between the results from the group with selective thoracic fusion (Group I) and from the group with both thoracic and lumbar curves fused (Group II). Type 2 double thoracic scoliosis: the correction of the upper thoracic curve, the first thoracic vertebral tilt, and left shoulder elevation were better in the group with both thoracic curves fused (Group I) than in the group with midthoracic fusion (Group II). Type 3 double major scoliosis: the lumbar curve correction was better in the group with both thoracic and lumbar curves fused (Group I) than in the group with selective thoracic fusion (Group II), and decompensation occurred more frequently in Group II. Type 4 triple major scoliosis: because there were only two patients with this type of curve, no analysis was completed. Type 5 thoracolumbar or lumbar curve: there was no difference between the results from the group with selective thoracolumbar or lumbar fusion (Group I) and the group with thoracic and lumbar curves fused (Group II). Type 6 double major scoliosis with larger lumbar curve: the thoracic curve correction was better in the group with both curves fused (Group I) than in the group with only the lumbar curve fused (Group II). Conclusion. Better radiologic results were achieved through the use of the Lenke classification system for theselection of fusion levels by avoiding unnecessary fusion of the nonstructural lumbar or thoracic spine as well as avoiding undercorrection of the structural secondary curves.

The impact of sagittal balance on clinical results after posterior interbody fusion for patients with degenerative spondylolisthesis: A Pilot study

BackgroundComparatively little is known about the relation between the sagittal vertical axis and clinical outcome in cases of degenerative lumbar spondylolisthesis. The objective of this study was to determine whether lumbar sagittal balance affects clinical outcomes after posterior interbody fusion. This series suggests that consideration of sagittal balance during posterior interbody fusion for degenerative spondylolisthesis can yield high levels of patient satisfaction and restore spinal balanceMethodsA retrospective study of clinical outcomes and a radiological review was performed on 18 patients with one or two level degenerative spondylolisthesis. Patients were divided into two groups: the patients without improvement in pelvic tilt, postoperatively (Group A; n = 10) and the patients with improvement in pelvic tilt postoperatively (Group B; n = 8). Pre- and postoperative clinical outcome surveys were administered to determine Visual Analogue Pain Scores (VAS) and Oswestry disability index (ODI). In addition, we evaluated full spine radiographic films for pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), sacrofemoral distance (SFD), and sacro C7 plumb line distance (SC7D)ResultsAll 18 patients underwent surgery principally for the relief of radicular leg pain and back pain. In groups A and B, mean preoperative VAS were 6.85 and 6.81, respectively, and these improved to 3.20 and 1.63 at last follow-up. Mean preoperative ODI were 43.2 and 50.4, respectively, and these improved to 23.6 and 18.9 at last follow-up. In spinopelvic parameters, no significant difference was found between preoperative and follow up variables except PT in Group A. However, significant difference was found between the preoperative and follows up values of PT, SS, TK, LL, and SFD/SC7D in Group B. Between parameters of group A and B, there is borderline significance on preoperative PT, preoperative LL and last follow up SS.Correlation analysis revealed the VAS improvements in Group A were significantly related to postoperative lumbar lordosis (Pearsons coefficient = -0.829; p = 0.003). Similarly, ODI improvements were also associated with postoperative lumbar lordosis (Pearsons coefficient = -0.700; p = 0.024). However, in Group B, VAS and ODI improvements were not found to be related to postoperative lumbar lordosis and to spinopelvic parameters.ConclusionIn the current series, patients improving PT after fusion were found to achieve good clinical outcomes in degenerative spondylolisthesis. Overall, our findings show that it is important to quantify sagittal spinopelvic parameters and promote sagittal balance when performing lumbar fusion for degenerative spondylolisthesis.

Different Risk Factors of Proximal Junctional Kyphosis and Proximal Junctional Failure Following Long Instrumented Fusion to the Sacrum for Adult Spinal Deformity: Survivorship Analysis of 160 Patients.

Background The failure modes, time to development, and clinical relevance are known to differ between proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). However, there are no reports that study the risk factors of PJK and PJF separately. Objective The aim of this study was to investigate the risk factors for PJK and PJF separately. Methods A retrospective study of 160 consecutive patients who underwent a long instrumented fusion to the sacrum for adult spinal deformity with a minimum follow-up of 2 years was conducted. A separate survivorship analysis of PJK and PJF was performed using the Cox proportional hazards model for the 3 categorical parameters of surgical, radiographic, and patient factors. Results PJK developed in 27 patients (16.9%) and PJF in 29 patients (18.1%). The median survival time was 17.0 months for PJK and 3.0 months for PJF. Multivariate analyses revealed that a high body mass index was an independent risk factor for PJK (hazard ratio [HR] = 1.179), whereas the significant risk factors for PJF were older age, the presence of osteoporosis, the uppermost instrumented vertebra level at T11-L1, and a greater preoperative sagittal vertical axis (HR = 1.082, 6.465, 5.236, and 1.017, respectively). A large correction of sagittal deformity was shown to be a risk factor for PJF on univariate analyses, but not on multivariate analyses. Conclusion PJK developed at a median of 17 months and PJF at a median of 3 months. A high body mass index was an independent risk factor for PJK, whereas older age, osteoporosis, uppermost instrumented vertebra level at the thoracolumbar junction, and greater preoperative sagittal vertical axis were risk factors for PJF.

Surgical results of metastatic spinal cord compression (MSCC) from non-small cell lung cancer (NSCLC): analysis of functional outcome, survival time, and complication.

BACKGROUND CONTEXT A number of studies have reported favorable surgical results for metastatic spinal tumors from various solid tumors. However, there are few data available on metastatic spinal cord compression (MSCC) from lung cancer despite its considerable frequency. PURPOSE The study aims to present the functional outcomes, survival time, and complications after surgical treatment for MSCC from non-small cell lung cancer (NSCLC). STUDY DESIGN/SETTING This is a longitudinal observational study. PATIENT SAMPLE The study includes 50 patients who had neurologic deficit and underwent surgical treatment for MSCC from NSCLC. OUTCOME MEASURES The Eastern Cooperative Oncology Group performance status (ECOG-PS), ambulatory status, overall survival, factors associated with survival time, and perioperative complications were analyzed. METHODS The postoperative changes of ECOG-PS and ambulatory status were assessed. The factors affecting postoperative ambulatory status were evaluated using logistic regression analysis. Survival time was calculated using the Kaplan-Meier method. To identify the prognostic factors, log-rank test and Cox hazards regression model were used for univariate and multivariate analyses, respectively. Major complications within postoperative 30 days and mortality rate were recorded. RESULTS The study cohort consisted of 27 males and 23 females with a mean age of 58.0±11.3 years at the time of surgery. An ECOG-PS improvement by at least one grade was observed in 33 of 50 cases (66.0%). Among 39 patients who were not ambulatory before surgery, 23 patients (59.0%) regained ambulatory ability after surgery. Patients who were preoperatively ambulant and those who underwent surgery within 72 hours from neurologic deficit had an increased chance of postoperative ambulation. The median for overall survival after surgery was 5.2 months. Five prognostic factors were identified on univariate analysis: time from neurologic deficit, responsiveness to preoperative chemotherapy, postoperative chemotherapy, postoperative ECOG-PS, and postoperative ambulatory status. Multivariate analysis revealed that time to neurologic deficit (risk ratio [RR]: 2.28, p=.023), postoperative chemotherapy (RR: 6.58, p<.001), and postoperative ECOG-PS (RR: 2.73, p=.040) were independent prognostic factors of survival time. Major complications developed in 34.0% of patients (17 of 50), and the 30-day mortality rate was 10.0% (5 of 50). CONCLUSIONS Functional improvements were observed through surgical treatment even with relatively high complication rates for MSCC from NSCLC. Earlier surgical treatment could act as an adjuvant therapy for prolonging survival by improving functional status.

The factors that influence the postoperative segmental range of motion after cervical artificial disc replacement

BACKGROUND CONTEXT Advantages of cervical artificial disc replacement (ADR) are to preserve segmental range of motion (ROM) and avoid adjacent segmental disease. To achieve successful outcome after cervical ADR, ROM maintenance is important, but few authors have investigated the factors that influence the postoperative segmental ROM. PURPOSE To evaluate the factors that influence the postoperative segmental ROM after cervical ADR. STUDY DESIGN/SETTING A retrospective clinical study. PATIENT SAMPLE Forty-one consecutive cervical ADR cases were analyzed. OUTCOME MEASURES Disc height, segmental and overall ROM, and clinical parameters checked with Neck Disability Index (NDI) and visual analog scale (VAS) in neck and arm pain were assessed. METHODS There were 21 men and 20 women with a mean age of 45 years (range, 27-61 years). All cases were followed up for more than 2 years (range, 24-54 months; average, 31 months). Angles of the inserted implant on the immediate postoperative lateral radiographs, segmental and overall ROM (full flexion angle-full extension angle), disc height increment (immediate postoperative disc height-preoperative disc height), and adjacent segment changes at cephalad and caudal disc space were measured. Correlations between the factors and segmental ROM at last follow-up were analyzed. RESULTS Mean preoperative NDI was improved from 61.0 preoperatively to 11.5 at last follow-up, and mean VAS in the neck pain decreased from 56.8 preoperatively to 11.8 postoperatively and arm pain decreased from 68.1 to 18.0. The mean preoperative segmental ROM changed from 7.4+/-3.2 degrees preoperatively to 10.4+/-5.9 degrees at last follow-up, and mean preoperative disc height increased from 6.4+/-1.0 (4.1-8.4) mm preoperatively to 7.9+/-1.0 (6.3-9.9) mm postoperatively. The segmental ROM at last follow-up was not significantly correlated with preoperative segmental and overall ROM, angle of inserted implant, VAS, or age (p>.05). However, the segmental ROM at last follow-up was significantly correlated with the disc height increment (p=.046, r=0.374) and preoperative NDI (p=.026, r=0.412). The patient group with the postoperative segmental ROM greater than 10 degrees had a significantly lower mean preoperative disc height than the group with the segmental ROM less than 10 degrees (p=.050). CONCLUSIONS At a minimum of 2 years after cervical ADR, clinical outcomes were satisfactory in terms of function and pain scores. Within our results, the segmental ROM was not affected by preoperative ROM but postoperative disc height increment positively and preoperative disc height negatively.

Mini-Open Approach for Direct Lateral Lumbar Interbody Fusion

Study Design Retrospective analysis. Purposes To introduce the mini-open lateral approach for the anterior lumbar interbody fusion (ALIF), and to investigate the advantages, technical pitfalls and complications by providing basic knowledge on extreme lateral interbody fusion (XLIF) or direct lumbar interbody fusion (DLIF). Overview of Literature Recently, minimally invasive lateral approach for the lumbar spine is revived and receiving popularity under the name of XLIF or DLIF by modification of mini-open method when using the sequential tubular dilator and special expandable retractor system. Methods Seventy-four patients who underwent surgery by the mini-open lateral approach from September 2000 to April 2008 with various disease entities were included. Blood losses, operation times, incision sizes, postoperative time to mobilization, length of hospital stays, technical problems and complications were all analyzed. Results The blood losses and operation times of patients who underwent simple ALIF were 61.2 mL and 86 minutes for one level, 107 mL and 106 minutes for two levels, 250 mL and 142.8 minutes for three levels, and 400 mL and 190 minutes for four levels of fusion. The incision sizes were on average 4.5 cm for one level, 6.3 cm for two levels, 8.5 cm for three levels and 10.0 cm for four levels of fusion. The complications were retroperitoneal hematoma (2 cases), pneumonia (1 case) and transient lumbosacral plexus palsy (3 cases). Conclusions Trials of mini-open lateral approach would be helpful before the trial of XLIF or DLIF. However, special attention is required for complications such as transient lumbosacral plexus palsy.

Survival-Related Factors of Spinal Metastasis with Hepatocellular Carcinoma in Current Surgical Treatment Modalities : A Single Institute Experience

Objective Recently, the survival of patients with hepatocellular carcinoma (HCC) has been prolonged with improvements in various diagnostic tools and medical treatment modalities. Consequently, spine metastases from HCC are being diagnosed more frequently. The accurate prediction of prognosis plays a critical role in determining a patients treatment plan, including surgery for patients with spinal metastases of HCC. We investigated the clinical features, surgical outcomes, and prognostic factors of HCC presenting with spine metastases, in patients who underwent surgery. Methods A retrospective review was conducted on 33 HCC patients who underwent 36 operations (three patients underwent surgical treatment twice) from February 2006 to December 2013. The median age of the patients was 56 years old (range, 28 to 71; male : female=30 : 3). Results Overall survival was not correlated with age, sex, level of metastases, preoperative Child-Pugh classification, preoperative ambulatory function, preoperative radiotherapy, type of operation, administration of Sorafenib, or the Tokuhashi scoring system. Only the Tomita scoring system was shown to be an independent prognostic factor for overall survival. Comparing the Child-Pugh classification and ambulatory ability, there were no statistically differences between patients pre- and post-operatively. Conclusion The Tomita scoring system represents a practicable and highly predictive prognostic tool. Even though surgical intervention may not restore ambulatory function, it should be considered to prevent deterioration of the patients overall condition. Additionally, aggressive management may be needed if there is any ambulatory ability remaining.

The Ideal Cage Position for Achieving Both Indirect Neural Decompression and Segmental Angle Restoration in Lateral Lumbar Interbody Fusion (LLIF).

Study Design: A prospective radiographic analysis. Objective: To assess the ideal cage position for lateral lumbar interbody fusion (LLIF) together. Summary of Background Data: Achieving both indirect decompression and restoration of the segmental angle (SA) appear to be contrary to one another because the anteriorly located cage might be advantageous for restoring the SA, and posteriorly located cage might be favorable for achieving the indirect decompression effect. Little has been known about the significance of cage position in LLIF. Methods: Forty-one patients who underwent LLIF followed by percutaneous pedicle screw fixation for 94 levels were evaluated. Postoperative plain radiographs and magnetic resonance images were obtained 3 days after surgery. The cage position was determined by the anterior, middle, and posterior portions. The anterior and posterior disk heights, SA, cross-sectional area of the thecal sac (CSA), and the foraminal area (FA) were compared according to the cage position. Results: The cage was placed in the anterior area for 31 levels and middle for 63 levels. The cage height was 13.0±1.3 degrees. The increases in anterior disk height and SA were significantly greater in the anterior group (9.1 mm, 6.1 degrees) than those of the middle group (6.7 mm, 2.4 degrees). Posterior disk height increased by a mean of 4.5 mm, but its change did not differ according to the cage position. CSA and FA increased by 36.5% and 69.6%, respectively. There were no significant differences in the CSA and FA increases with respect to the cage position. Regression analysis showed that the increase of SA was affected by cage position, but the increase ratios of CSA and FA were not affected. Conclusions: The cage position within the anterior 1/3 of disk space is better for achieving the restoration of the SA without compromising the indirect neural decompression, if the height of cage is large enough.

Mini-Open Anterior Lumbar Interbody Fusion Combined with Lateral Lumbar Interbody Fusion in Corrective Surgery for Adult Spinal Deformity

Study Design Prospective observational study. Purpose To introduce the techniques and present the surgical outcomes of mini-open anterior lumbar interbody fusion (ALIF) at the most caudal segments of the spine combined with lateral lumbar interbody fusion (LLIF) for the correction of adult spinal deformity Overview of Literature Although LLIF is increasingly used to correct adult spinal deformity, the correction of sagittal plane deformity with LLIF alone is reportedly suboptimal. Methods Thirty-two consecutive patients with adult spinal deformity underwent LLIF combined with mini-open ALIF at the L5–S1 or L4–S1 levels followed by 2-stage posterior fixation. ALIF was performed for a mean 1.3 levels and LLIF for a mean 2.7 levels. Then, percutaneous fixation was performed in 11 patients (percutaneous group), open correction with facetectomy with or without laminectomy in 16 (open group), and additional pedicle subtraction osteotomy (PSO) in 5 (PSO group). Spinopelvic parameters were compared preoperatively and postoperatively. Hospitalization data and clinical outcomes were recorded. Results No major medical complications developed, and clinical outcomes improved postoperatively in all groups. The mean postoperative segmental lordosis was greater after ALIF (17.5°±5.5°) than after LLIF (8.1°±5.3°, p <0.001). Four patients (12.5%) had lumbar lordosis with a pelvic incidence of ±9° preoperatively, whereas this outcome was achieved postoperatively in 30 patients (93.8%). The total increase in lumbar lordosis was 14.7° in the percutaneous group, 35.3° in the open group, and 57.0° in the PSO group. The ranges of potential lumbar lordosis increase were estimated as 4°–25°, 23°–42°, and 45°–65°, respectively. Conclusions Mini-open ALIF combined with LLIF followed by posterior fixation may be a feasible technique for achieving optimal sagittal balance and reducing the necessity of more extensive surgery.