Posterolateral Lumbar Fusion Research Articles

Geographic variations in the cost of spine surgery.

Retrospective review. To define the geographic variation in costs of anterior cervical discectomy and fusion (ACDF) and posterolateral fusion (PLF). ACDF and lumbar PLF are common procedures that are used in the treatment of spinal pathologies. To optimize value, both the benefits and costs of an intervention must be quantified. Data on costs are scarce in comparison with data on total charges. This study aims at defining the costs of ACDF and PLF and describing the geographic variation within the United States. Medicare Provider Utilization and Payment data were used to investigate the costs associated with ACDF, PLF, and total knee arthroplasty (TKA). Average total costs of the procedures were compared by state and geographic region. Combined professional and facility costs for a single-level ACDF had a national mean of $13,899. Total costs for a single-level PLF had a mean of $25,858. Total costs for a primary TKA had a national mean of $13,039. The cost increased to an average of $22,138 for TKA with major comorbidities. Analysis of geographic trends showed statistically significant differences in total costs of PLF, TKA, and TKA, with major complications or comorbidities between geographic regions (P < 0.01 for all). Three of the 4 procedures (PLF, TKA, and TKA with major complications or comorbidities) showed statistically significant variation in cost between geographic regions. The Midwest provided the lowest cost for all procedures. Similar geographic trends in the cost of spinal fusions and TKAs suggest that these trends may not be limited to spine-related procedures. Surgical costs were found to correlate with cost of living but were not associated with the population of the state. These data shed light on the actual cost of common surgical procedures throughout the United States and will allow further progress toward the development of cost-effective, value-driven care. 3.

What are the Risk Factors for Cerebrovascular Accidents After Elective Orthopaedic Surgery?

Perioperative cerebrovascular accidents (CVAs) are one of the leading causes of patient morbidity, mortality, and medical costs. However, little is known regarding the rates of these events and risk factors for CVA after elective orthopaedic surgery. Our goals were to (1) establish the national, baseline proportion of patients experiencing a 30-day CVA and the timing of CVA; and (2) determine independent risk factors for 30-day CVA rates after common elective orthopaedic procedures. Patients undergoing elective TKA, THA, posterior or posterolateral lumbar fusion, anterior cervical discectomy and fusion, and total shoulder arthroplasty, from 2006 to 2012, were identified from the American College of Surgeons National Surgical Quality Improvement Program(®) database. A total of 42,150 patients met inclusion criteria. Thirty-day CVA rates were recorded for each procedure, and patients were assessed for characteristics associated with CVA through univariate analysis. Multivariate regression models were created to identify independent risk factors for CVA. A total of 55 (0.13%) patients experienced a CVA within 30 days of the procedure, occurring a median of 2 days after surgery (range, 1-30 days) with 0.08% of patients experiencing a CVA after TKA, 0.15% after THA, 0.00% after single-level anterior cervical discectomy and fusion, 0.38% after multilevel anterior cervical discectomy and fusions, 0.20% after single-level posterior or posterolateral lumbar fusion, 0.70% after multilevel posterior or posterolateral lumbar fusion, and 0.22% after total shoulder arthroplasty. Independent risk factors for CVA included age of 75 years or older (odds ratio [OR], 2.50; 95% CI, 1.44-4.35; p = 0.001), insulin-dependent diabetes mellitus (OR, 3.08; CI, 1.47-6.45; p = 0.003), hypertension (OR, 2.71; CI, 1.19-6.13; p = 0.017), history of transient ischemic attack (OR, 2.83; CI, 1.24-6.45; p = 0.013), dyspnea (OR, 2.51; CI, 1.30-4.86; p = 0.006), chronic obstructive pulmonary disease (OR, 2.33; CI, 1.06-5.13; p = 0.036), and operative time of 180 minutes or greater (OR, 3.25; CI 1.60-6.60; p = 0.001). Numerous nonmodifiable patient comorbidities and increased operative time were associated with CVA after elective orthopaedic procedures. However, the American College of Surgeons National Surgical Quality Improvement Program(®) database does not code for cardiac arrhythmia or atrial fibrillation, which other studies have suggested may be important predictor variables; those may be important risk factors, although we were unable to evaluate them in our study. Surgeons should counsel patients with these risk factors and limit their operative time to reduce the risk of these adverse events, and future studies should examine other patient characteristics such as arrhythmia and noncoronary heart disease and assess the role of pharmacologic prophylaxis in patients with these risk factors. Level III, prognostic study.

A Systematic Review of Lumbar Fusion Rates With and Without the Use of rhBMP-2.

Systematic review. To evaluate literature comparing fusion rates in anterior lumbar interbody fusion (ALIF), posterior lumbar interbody/transforaminal lumbar interbody fusion (PLIF/TLIF), and posterolateral lumbar fusion (PLF) with and without recombinant human bone morphogenetic protein-2 (rhBMP-2). rhBMP-2 is used for the FDA-approved indication of single-level ALIF with LT-Cage and off-label for PLIF/TLIF, and PLF. Due to recent controversies, it is essential to evaluate the literature for its effects on fusion rates to evaluate whether benefits outweigh potential complications. A Medline search was performed of clinical studies published between May 2000 and May 2012 comparing fusion rates after ALIF, PLIF/TLIF, and PLF surgery with versus without rhBMP-2. Only studies with a control arm were reviewed. 16 studies were reviewed (1794 patients, 995 treated with rhBMP-2 and 799 without). 5 of 5 studies for PLIF/TLIF (including 301 of 301 patients), 1 of 4 for ALIF (including 279 of 589 patients), and 3 of 7 for PLF (including 272 of 904 patients) reported no significant improvement in fusion rates with rhBMP-2 compared with those without rhBMP-2 at longest follow-up investigated. Average fusion rate 24 months after surgery was 97.8% for ALIF (n = 316), 95.7% for PLIF/TLIF (n = 141), and 93.6% for PLF (n = 422) with rhBMP-2 and 88.2% (n = 228), 89.5% (n = 86), and 83.1% (n = 372) without rhBMP-2, for ALIF, PLIF/TLIF, and PLF, respectively. Odds ratio of fusion were calculated as 7.08 (95% CI: 1.54-32.7) in ALIF, 1.98 (95% CI: 0.39-10.1) in PLIF/TLIF, and 3.06 (95% CI: 1.61-5.80) in PLF with rhBMP-2 as compared with without rhBMP-2. Although numerous studies did not show statistically significant improvement in fusion rates with rhBMP-2 use, analysis of combined studies revealed significant improvement in fusion rate with rhBMP-2 in ALIF and PLF patients. Notably, even when pooling data from several studies, rhBMP-2 did not result in statistically significantly improved fusion rates in PLIF/TLIF. However, heterogeneity of rhBMP-2 dosing, surgical techniques, and quality of papers reviewed may limit the validity of conclusions drawn. 4.

Impact of Age on Short-term Outcomes After Lumbar Fusion: An Analysis of 1395 Patients Stratified by Decade Cohorts.

The safety and efficacy of spinal fusion in the elderly population remains uncertain with conflicting data. To determine if elderly patients undergoing instrumented lumbar fusion have increased 30-day complication rates compared to younger patients. The American College of Surgeons National Surgical Quality Improvement Program was used to identify all patients undergoing instrumented posterolateral lumbar fusion between 2005 and 2011. Patients were stratified by decade cohorts as follows: <65, 65 to 75, 75 to 85, and ≥85 years old. All 30-day complications were grouped as overall composite morbidity and were compared using multivariate analysis. A total of 1395 patients were identified and the overall 30-day complication rate was 11.47%. The complication rates were 9.04% and 14.05% for patients younger than 65 and older than 65, respectively. When stratified by decade cohorts, the complication rates were 9.04% for the <65 cohort, 13.46% for the 65 to 75 cohort, 16.17% for the >75 to 85 cohort, and 4.00% for the ≥85 cohort. Multivariable regression analysis revealed no statistically significant difference between the <65 and ≥65 age cohorts (odds ratio = 1.26; 95% confidence interval: 0.87-2.19). After stratifying into age cohorts, multivariable analyses revealed no difference in odds of postoperative complication occurrence for any age cohort when compared with the referent group (<65 years of age). Patients older than 65 years of age have significantly higher rates of complications after lumbar fusion when compared to younger patients. However, multivariable analysis revealed that age was not an independent risk factor for complication occurrence after lumbar fusion.

Developing a Mouse Model to Study Mesenchymal Stem Cell Survival, Proliferation, and Migration in Lumbar Posterolateral Spinal Fusion

Introduction While spinal fusion surgery has advanced over the past decade, a great deal is unknown regarding the underlying mechanisms that contribute to spinal fusion failure or pseudoarthrosis. Clinically, bone marrow aspirate has been successfully used alongside a variety of grafting materials to augment fusion (Neen et al. Spine (Phila Pa 1976). 2006;31(18):E636; Carter et al. Spine J. 2009;9(6):434). To date, studies evaluating these procedures have focused on radiographic monitoring and endpoint analysis. Little is known about the survival and proliferation of these transplanted mesenchymal cells or how much they contribute to bone formation compared with host cells from adjacent decorticated bone. Insights into these cell dynamics will give us a deeper understanding of the biological processes underlying spinal fusion and allow for evaluation and development of fusion therapies that reduce rates of pseudoarthrosis. Material and Methods A total of 40 FVB/NJ mice underwent posterolateral lumbar spinal fusion surgery and were divided into four groups based upon the fusion graft employed: syngeneic iliac crest bone graft ( n = 10), Vitoss bone-matrix alone ( n = 10), Vitoss bone-matrix with syngeneic bone marrow cells (2.5 × 106 cell/side) ( n = 10), and Vitoss bone-matrix with transgenic luciferase-expressing syngeneic bone marrow cells (2.5 × 106 cell/side) ( n = 10). Bone marrow cells were isolated from the long bones of either syngeneic FVB/NJ mice or syngeneic FVB mice which constitutively express the luciferase gene (FVB-Tg (CAG-luc,-GFP) L2G85Chco/J mice). The in vivo survival, distribution, and proliferation of the luciferase-expressing bone marrow-derived cells were monitored via bioluminescence imaging over a period of 8 weeks. Spinal fusion was assessed 4, 6, and 8 weeks postsurgery via micro-CT imaging, as well as via manual palpation at 8 weeks. Immunohistochemistry was performed to assess fusion bone growth as well as determine the number of donor versus host cells within the fusion mass. Results Bioluminescent imaging data demonstrated quantifiable cellular viability within the fusion mass as early as 24 hours following surgery, with increasing bioluminescent signal over the first 2 weeks postsurgery, thus indicating cellular proliferation. Bioluminescence decreased between weeks 4 and 8 suggesting a loss of transplanted mesenchymal progenitor cells within the fusion mass at later time points. Correlations with histology and micro-CT imaging of the developing fusion mass are currently under analysis. Conclusions We have demonstrated a novel murine model which enables noninvasive in vivo monitoring of implanted transgenic luciferase-expressing bone marrow cells following spinal fusion surgery. Future applications of this model will include the assessment of additional therapeutics for improving spinal fusion in translational research studies.

The Outcome of Pedicle Screw Instrumentation Removal for Chronic Low Back Pain

Introduction There have been a limited number of small case series reporting improvement in patients' function and pain scores following removal of pedicle screw metalwork for nontraumatic lumbar fusion surgery. The investigators' aim was to determine the degree of satisfaction from a patient cohort; and improvement in pain status after removal of pedicle screw instrumentation and factors that may influence the outcome. Methods Patients who had removal of pedicle screw instrumentation for posterolateral lumbar fusion in the preceding 2 years were identified from the database of a single spinal surgeon's case series. All patients completed pre- and postoperative Oswestry Low Back Pain Disability Questionnaire (ODI). Patient inclusion criteria were persistent axial low back pain imaging confirmed solid fusion, nonradicular symptoms and no other cause found for pain, for example, infection. Exclusion criteria included exchange of metal work, revision fusion, or other additional therapeutic procedures. Following removal of metal work via previous incisions, all patients had debridement of fibromuscular tissue and adhesiolysis, thorough saline lavage, and local bone grafting to the site of metal removal. Results A total of 21 patients were identified from the database with a mean follow-up of 14 months (range, 3–24 months). There were two postoperative hematomas requiring aspiration but no additional complications such infections, reoperations, or deterioration of neurological deficits. The former two patients did not record improvement in VAS and both were neutral in satisfaction. Treatment success as assessed from the ODI analysis was rated as excellent in 6 of 21, good in 7 of 21, fair in 5 of 21, and poor in 2 of 21. Reduced class II opioids, benzodiazepines, or neuromodulator use was reduced in 7of 21, no different in 11of 21, and increased in 3 of 21. The proportion of patients with an improvement in VAS was 13 of 21 (62%) with an improvement of at least 2 or more being (43%) 9 of 21 of patients surveyed. The visual analog scores were the only component of the ODI able to be assessed for all of the patients with mean scores of 5.9 preoperatively to 4.2 postoperatively ( p = 0.04). The proportion of patients with an improvement in VAS was 13 of 21 (62%) with an improvement of 2 or more being 9 of 21 (43%) of patients surveyed. Patients who did not receive analgesic benefit and/or had lower satisfaction from the removal of instrumentation procedure tended to be male, compensable, had experienced more years of symptoms, shorter times to metal wear removal, and an increased prevalence of preoperative class II opioid requirements. There was, however, no trend to a difference with regards to number or location of levels fused, number of procedures, presence of pseudoarthrosis or broken/loose metal wear and method of preoperative fusion confirmation. Of the 21 patients, 14 (67%) patients indicated that they would undergo the same treatment again given their experience and outcome. Conclusion In our series, removal of pedicle screw implants in individuals with ongoing low back pain following solid fusion lead to good or excellent results in two-third of patients and did not lead to any adverse effects and/or complications.

The fate of adjacent segments with pre-existing degeneration after lumbar posterolateral fusion: the influence of degenerative grading.

To evaluate the impact of pre-existing disc degeneration and its extent on future adjacent segment degeneration (ASDeg) after lumbar posterolateral fusion (PLF). A total of 102 patients who had undergone PLF for degenerative lumbar diseases from January 2006 to December 2008 were retrospectively reviewed by using radiography and clinical evaluation. The University of California at Los Angeles (UCLA) grading scale was used to evaluate the extent of disc degeneration. The Visual Analog Scale, Oswestry Disability Index, and SF-36 questionnaire were used to evaluate clinical outcomes. The overall prevalence of radiological ASDeg was 25.5 %, and the prevalence of ASDeg for the cranial and caudal levels was 19.6 and 15.1 %, respectively. The prevalence of ASDeg in one-, two-, and three-level fusion was 15.8, 26.3, and 50 %, respectively (p = 0.008). For the cranial level, the preoperative UCLA grade A, B, and C groups had prevalence values for ASDeg of 13.5, 28.6, and 42.9 %, respectively (p = 0.026). A higher prevalence of ASDeg was found in cranial discs with pre-existing degeneration than in the group without pre-existing degeneration (p = 0.012). The group without pre-existing degeneration showed better outcomes. For the caudal level, there was no significant difference in ASDeg prevalence. At final follow-up, the group without pre-existing disc degeneration showed better outcomes than the group with pre-existing disc degeneration. Adjacent segment discs with pre-existing degeneration had a higher likelihood of ASDeg progression compared with normal discs, especially for those classified as UCLA grade C.

Synthetic bone mimetic matrix-mediated in situ bone tissue formation through host cell recruitment

Advances in tissue engineering have offered new opportunities to restore anatomically and functionally compromised tissues. Although traditional tissue engineering approaches that utilize biomaterials and cells to create tissue constructs for implantation or biomaterials as a scaffold to deliver cells are promising, strategies that can activate endogenous cells to promote tissue repair are more clinically attractive. Here, we demonstrate that an engineered injectable matrix mimicking a calcium phosphate (CaP)-rich bone-specific microenvironment can recruit endogenous cells to form bone tissues in vivo. Comparison of matrix alone with that of bone marrow-soaked or bFGF-soaked matrix demonstrates similar extent of neo-bone formation and bridging of decorticated transverse processes in a posterolateral lumbar fusion rat model. Synthetic biomaterials that stimulate endogenous cells without the need for biologics to assist tissue repair could circumvent limitations associated with conventional tissue engineering approaches, including ex vivo cell processing and laborious efforts, thereby accelerating the translational aspects of regenerative medicine.

Posterior lumbar interbody fusion and posterolateral fusion: Analogous procedures in decreasing the index of disability in patients with spondylolisthesis.

Objective:The purpose of this study was to evaluate the disability in patients with spondylolisthesis who assigned either to posterolateral fusion (PLF) or posterior lumbar interbody fusion (PLIF) and to compare it between two groups.Methods:In a prospective observational study, 102 surgical candidates with low-grade degenerative and isthmic spondylolisthesis enrolled from 2012 to 2014, and randomly assigned into two groups: PLF and PLIF. Evaluation of disability has been done by a questionnaire using Oswestry Disability Index (ODI). The questionnaire was completed by all patients before the surgery, the day after surgery, after 6 months and after 1-year.Results:There were no statistically significant differences in terms of age and sex distribution and pre-operation ODI between groups (P > 0.05). Comparison of the mean ODI scores of two groups over the whole study period showed no significant statistical difference (P = 0.074). ODIs also showed no significant differences between two groups the day after surgery, 6th months and 1-year after surgery (P = 0.385, P = 0.093, P = 0.122 and P = 433) respectively. Analyzing the course of ODI over the study period, showed a significant descending pattern for either of groups (P < 0.0001).Conclusion:Both surgical fusion techniques (PLF and PLIF) were efficient to lessen the disability of patients with spondylolisthesis, and none of the fusion techniques were related to a better outcome in terms of disability.

Posterolateral instrumented lumbar fusion in patients spondylolisthesis treated with locally harvested bone and allografts mixed with bone marrow

Posterolateral instrumented lumbar fusion in patients spondylolisthesis treated with locally harvested bone and allografts mixed with bone marrow

The importance of proximal fusion level selection for outcomes of multi-level lumbar posterolateral fusion.

BackgroundThere are few studies about risk factors for poor outcomes from multi-level lumbar posterolateral fusion limited to three or four level lumbar posterolateral fusions. The purpose of this study was to analyze the outcomes of multi-level lumbar posterolateral fusion and to search for possible risk factors for poor surgical outcomes.MethodsWe retrospectively analyzed 37 consecutive patients who underwent multi-level lumbar or lumbosacral posterolateral fusion with posterior instrumentation. The outcomes were deemed either 'good' or 'bad' based on clinical and radiological results. Many demographic and radiological factors were analyzed to examine potential risk factors for poor outcomes. Student t-test, Fisher exact test, and the chi-square test were used based on the nature of the variables. Multiple logistic regression analysis was used to exclude confounding factors.ResultsTwenty cases showed a good outcome (group A, 54.1%) and 17 cases showed a bad outcome (group B, 45.9%). The overall fusion rate was 70.3%. The revision procedures (group A: 1/20, 5.0%; group B: 4/17, 23.5%), proximal fusion to L2 (group A: 5/20, 25.0%; group B: 10/17, 58.8%), and severity of stenosis (group A: 12/19, 63.3%; group B: 3/11, 27.3%) were adopted as possible related factors to the outcome in univariate analysis. Multiple logistic regression analysis revealed that only the proximal fusion level (superior instrumented vertebra, SIV) was a significant risk factor. The cases in which SIV was L2 showed inferior outcomes than those in which SIV was L3. The odds ratio was 6.562 (95% confidence interval, 1.259 to 34.203).ConclusionsThe overall outcome of multi-level lumbar or lumbosacral posterolateral fusion was not as high as we had hoped it would be. Whether the SIV was L2 or L3 was the only significant risk factor identified for poor outcomes in multi-level lumbar or lumbosacral posterolateral fusion in the current study. Thus, the authors recommend that proximal fusion levels be carefully determined when multi-level lumbar fusions are considered.

Posterolateral lumbar fusion: Relationship between computed tomography Hounsfield units and symptomatic pseudoarthrosis.

Background:Assessment of bone quality can guide spinal surgery. However, surgeons infrequently evaluate bone quality in a quantitative manner. Recent literature suggests a role for computed tomography (CT) Hounsfield units (HUs) as a marker for bone quality. Limited data exist regarding its utility with respect to posterolateral lumbar fusion (PLF).Methods:From fall 2010 to winter 2012, 10 patients underwent revision surgery for symptomatic pseudoarthrosis (defined as intractable pain associated with either radiographic evidence of nonunion or intraoperative evidence of nonunion) after a prior L4–S1 PLF. These patients were age-matched (±5 years) to 10 patients who underwent L4–S1 PLF with no clinical signs of pseudoarthrosis at 1-year follow-up. Available CT imaging (with or without instrumentation) was evaluated from L1 to L5 for the averaged HU. Data were pooled among L1–L3 values and between L4 and L5 values.Results:Within the pseudoarthrosis group, the pooled L1–L3 HU value was similar to the pooled L4–L5 HU value (168.39 ± 22.84 HU vs. 166.98 ± 23.20 HU respectively, P = 0.89). The same pattern was observed for the control group (190.24 ± 37.13 HU vs. 201.89 ± 36.59 HU respectively, P = 0.44). On the other hand, the pooled L1–L3 and L4–L5 HU values were larger for the control group compared to the pseudoarthrosis group, with the pooled L4–L5 HU demonstrating statistical significance, P = 0.01.Conclusion:Currently, CT imaging is typically not obtained prior to lumbar fusion. Results demonstrated that CT HU values were significantly larger for patients who did not exhibit symptomatic pseudoarthrosis at 1-year follow-up compared to those who required revision surgery. As such, CT HU values may serve as a predictor for bony fusion to guide surgical management of patients under consideration for PLF.

Effect of low-intensity pulsed ultrasound on posterolateral lumbar fusion of rabbit.

To observe the effect of low-intensity pulsed ultrasound in the posterolateral lumbar fusion of rabbit. A total of 48 New Zealand white rabbits were randomly divided into the observation group and control group, including the autogenous iliac observation group, artificial bone observation group, artificial bone control group and autogenous iliac control group according to the different bone grafting. The posterolateral lumbar fusion of rabbits in each group was analyzed and compared. After 4 weeks of treatment using the low-intensity pulsed ultrasound, the fusion in the bone grafting area of observation group was good. There was the relatively dense fusion area between the right transverse process and artificial bone. The left transverse process had been completely fused, with the clear bone trabecula through the fusion area. There was no significant fusion sign in the control group. According to the fusion comparison between two groups, the fusion rate of the observation group was 83.3% and it was significantly higher than the one of the control group (37.5%). Results of the comparison were statistically significant (P<0.05). The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the iliac observation group were significantly higher than ones of the iliac control group (P<0.05). The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the artificial bone observation group were significantly higher than ones of the artificial bone control group (P<0.05). The expression of IL-1, IL-6 and IL-17 4 weeks after the treatment of the observation group was significantly lower than the one of the control group, with the statistical significance (P<0.05). It indicated that the treatment of low-intensity pulsed ultrasound could reduce the expression level of inflammatory factors. The low-intensity pulsed ultrasound can significantly increase the bone grafting fusion rate of the rabbit's posterolateral lumbar fusion. The possible mechanism is that it promotes the lumbar posterolateral endochondral ossification and reduces the inflammatory reaction.

Adjacent level disease following lumbar spine surgery: A review.

Background:Instrumented lumbar spine surgery is associated with an increased risk of adjacent segment disease (ASD). Multiple studies have explored the various risk factors contributing to ASD that include; fusion length (especially, three or more levels), sagittal malalignment, facet injury, advanced age, and prior cephalad degenerative disease.Methods:In this selective review of ASD, following predominantly instrumented fusions for lumbar degenerative disease, patients typically underwent open versus minimally invasive surgery (MIS), transforaminal lumbar interbody fusions (TLIFs), posterior lumbar interbody fusions (PLIFs), or rarely posterolateral lumbar instrumented or noninstrumented fusions (posterolateral lumbar fusion).Results:The incidence of ASD, following open or MI lumbar instrumented fusions, ranged up to 30%; notably, the addition of instrumentation in different series did not correlate with improved outcomes. Alternatively, in one series, at 164 postoperative months, noninstrumented lumbar fusions reduced the incidence of ASD to 5.6% versus 18.5% for ASD performed with instrumentation. Of interest, dynamic instrumented/stabilization techniques did not protect patients from ASD. Furthermore, in a series of 513 MIS TLIF, there was a 15.6% incidence of perioperative complications that included; a 5.1% frequency of durotomy and a 2.3% instrumentation failure rate.Conclusions:The incidence of postoperative ASD (up to 30%) is greater following either open or MIS instrumented lumbar fusions (e.g., TLIF/PLIF), while decompressions with noninstrumented fusions led to a much smaller 5.6% risk of ASD. Other findings included: MIS instrumented fusions contributed to higher perioperative complication rates, and dynamic stabilization did not protect against ASD.

The Effect of Teriparatide in Women with Osteoporosis after Lumbar Posterolateral Fusion or Posterior Lumbar Interbody Fusion

Study Design: Retrospective study. Objectives: To i�vesti��te r�dio�o�ic ��d c�i�ic�� outco�es o� terip�r�tide i� �o�e� �it� osteoporosis ��ter i�stru�e�ted �u���r pos� tero��ter�� �usio� (PLF) or posterior �u���r i�ter�ody �usio� (PLIF). Summary of Literature Review: Terip�r�tide �cce�er�ted �u���r postero��ter�� �usio� i� �o�e� �it� post�e�op�us�� osteoporosis. M�teri��s ��d Met�ods: Ei��ty�six �o�e� o�der t��� 65 ye�rs o�d �it� osteoporosis u�der�e�t PLF or PLIF �it� �o�e �r��t �et�ee� Fe�ru�r, 2011 �to M�y, 2012 pP�tie�ts �ere divided i�to �our �roup: terip�r�tide �roup �it� �oc�� �o�e (A�1: 13 p�tie�ts;, terip�r�tide �roup �it� co�posite �o�e (A�2: 27 p�tie�ts; �o��terip�r�tide �roup �it� �oc�� �o�e (B�1: 14 p�tie�ts; ��d �o��terip�r�tide �roup �it� co�posite �o�e (B�2: 32 p�tie�ts). At 3, 6, ��d 12 �o�t�s postoper�tive�y, t�e Os�estry Dis��i�ity I�dex (ODI), visu�� ����o� sc��e (VAS), �usio� r�te, ��d period o� �o�e u�io� �ere ev��u�ted. Results: VAS ��d ODI i�proved ��ter sur�ery i� ��� �roups, �ut �o si��ific��t di��ere�ces �ere �ote�� ��o�� t�e �roupses Furt�er, t�ere ��s �o si��ific��t di��ere�ce ��o�� t�e �roups �or ��e� �usio� �eve�, ��d �usiops(p>0.05). Fusio� r�te ��s 94.44% i� t�e A�1 �roup, 92.59% i� t�e A�2 �roup, 79.17% i� t�e B�1 �roup, ��d 76.92% i� t�e B�2 �roup. Aver��e period o� �o�e u�io� ��s 3.25 �o�t�s, 3.65 �o�t�s, 5.67 �o�t�s, ��d 5.65 �o�t�s respective�y. Fusio� r�te ��d �ver��e �o�e u�io� ti�e ��de �o si��ific��t di��ere�ee� ��o�� t�e �roups divided �y �r��t ��teri��s (p>0.05). Ho�ever, t�ose i� t�e terip�r�tide �roup �ere si��ific��t�y superior to t�ose i� t�e �o�� terip�r�tide �roup (p<0.05). Conclusions: I� �o�e� �it� osteoporosis ��ter PLF or PLIF �it� �o�e�r��t, terip�r�tide s�o�ed superiority i� t�e r�te o� �usio� ��d t�e period o� �o�e u�io�.

More than 6 Months of Teriparatide Treatment Was More Effective for Bone Union than Shorter Treatment Following Lumbar Posterolateral Fusion Surgery.

Study DesignRetrospective case series.PurposeTo examine the most effective duration of teriparatide use for spinal fusion in women with postmenopausal osteoporosis.Overview of LiteratureWe reported that daily subcutaneous injection of teriparatide (parathyroid hormone) significantly improved bone union after instrumented lumbar posterolateral fusion (PLF) in women with postmenopausal osteoporosis when compared with oral administration of bisphosphonate. However, the most effective duration of teriparatide use for spinal fusion has not been explored.MethodsForty-five women with osteoporosis diagnosed with degenerative spondylolisthesis from one of the three treatment groups were evaluated based on: short-duration treatment (average, 5.5 months; n=15; daily subcutaneous injection of 20 µg teriparatide), long-duration treatment (average, 13.0 months; n=15; daily subcutaneous injection of 20 µg teriparatide), and bisphosphonate treatment (average, 13.0 months; n=15; weekly oral administration of 17.5 mg risedronate). All patients underwent PLF with a local bone graft. Fusion rate and duration of bone union were evaluated 1.5 years after surgery.ResultsBone union rate and average duration for bone union were 92% and 7.5 months in the long-duration treatment group, 80% and 8.5 months in the short-duration treatment group, and 70% and 10.0 months in the bisphosphonate treatment group, respectively. Results of bone union rate and average duration for bone union in the teriparatide treatment groups were significantly superior to those in the bisphosphonate treatment group (p<0.05); whereas, significantly superior results were observed in long-duration treatment group when compared with short-duration treatment group (p<0.05).ConclusionsDaily injection of teriparatide for bone union was more effective than oral administration of bisphosphonate. Furthermore, a longer period of teriparatide treatment for bone union was more effective than a shorter period of same treatment.

Union Rates of Autologous Bone Marrow, Local Autobone and Biphasic Calcium Phosphate Mixed Graft in Lumbar Posterolateral Fusion

Union Rates of Autologous Bone Marrow, Local Autobone and Biphasic Calcium Phosphate Mixed Graft in Lumbar Posterolateral Fusion

Obesity Increases Perioperative Complications after Elective Degenerative Posterior Lumbar Fusions: A Prospective Study

Study design: Prospective observational study of consecutive patients. Objective: Body Mass Index (BMI) has recently been investigated for its association with adverse events during lumbar fusion surgery and remains a controversial issue. We attempt to evaluate the impact of BMI on the incidence of perioperative complications after elective, degenerative, posterior lumbar fusions in a surgery-naive population. Methods: We prospectively studied 77 consecutive patients undergoing open posterolateral lumbar fusion procedures at a single tertiary care center. Perioperative adverse events were defined by previously published reports and collected during the inpatient stay. Inclusion criteria reflected patients undergoing elective instrumented lumbar fusions while patients with revision surgery or history of infection, trauma or tumor were excluded from the study. Results: There were 39 non-obese (BMI 30) patients. Overall, 38% of patients suffered at least one complication. Forty one total complications occurred, 76% of those were minor and 24% were major complications. There was a significant difference in the rate of total complications between two groups with 13 adverse events in non-obese and 28 events in obese group (p=.028). Using a backward elimination multivariate stepwise regression model based on maximum likelihood, obesity was an independent predictor of total complications (p=0.02, OR 1.082, 95% confidence interval 1.012-1.157). Conclusion: Lumbar fusion surgery is one of the most common spinal procedures and continues to be on the rise over the past decade. This prospective evaluation of patients undergoing elective degenerative lumbar fusions correlated obesity with increased incidence of total perioperative complications. These results argue for a more conservative approach and stringent surgical selection in obese patients.

Posterolateral lumbar fusion for osteoporotic vertebral fracture with delayed paraplegia

Posterolateral lumbar fusion for osteoporotic vertebral fracture with delayed paraplegia

Effectiveness of Posterolateral Lumbar Fusion Varies with the Physical Properties of Demineralized Bone Matrix Strip.

Study DesignA randomized, controlled animal study.PurposeTo investigate the effectiveness of fusion and new bone formation induced by demineralized bone matrix (DBM) strips with jelly strengths.Overview of LiteratureThe form of the DBM can make a difference to the outcome. The effect of different jelly strengths on the ability of DBM to form new bone is not known.MethodsForty-eight rabbits were randomized into a control group and two experimental groups. In the control group (group 1), 1.4 g of autologous iliac crest bone was placed bilaterally. In the experimental groups, a high jelly strength DBM-hyaluronic acid (HA)-gelatin strip (group 2) and a low jelly strength DBM-HA-gelatin strip (group 3) were used. The fusion was assessed with manual manipulation and radiographs. The volume of the fusion mass was determined from computed tomographic images.ResultsThe fusion rates as determined by manual palpation were 37.5%, 93.8% and 50.0% in group 1, group 2, and group 3, respectively (p<0.05). By radiography, the fusion rate of High jelly strength DBM strip was statistically significantly greater than that of the other alternatives (p<0.05). The mean bone volume of the fusion mass as determined by computed tomography was 2,142.2±318.5 mm3, 3,132.9±632.1 mm3, and 2,741.5±380.4 mm3 in group 1, group 2, and group 3, respectively (p<0.05).ConclusionsThese results indicate that differences in the structural and mechanical properties of gelatin that are associated with jelly strength influenced cellular responses such as cell viability and bony tissue ingrowth, facilitating greater bone fusion around high jelly strength implants.