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Biomedical subjects

Rick B Delamarter

Publications and source records attributed to Rick B Delamarter.

18 recordsLinked to original sources
PubMed2006

Intervariability and intravariability of bone morphogenetic proteins in commercially available demineralized bone matrix products.

STUDY DESIGN: Enzyme-linked immunosorbent assay was used to detect bone morphogenetic proteins (BMPs) 2, 4, and 7 in 9 commercially available ("off the shelf") demineralized bone matrix (DBM) product formulations using 3 different manufacturer's production lots of each DBM formulation. OBJECTIVES: To evaluate and compare the quantity of BMPs among several different DBM formulations (inter-product variability), as well as examine the variability of these proteins in different production lots within the same DBM formulation (intra-product variability). SUMMARY OF BACKGROUND DATA: DBMs are commonly used to augment available bone graft in spinal fusion procedures. Surgeons are presented with an ever-increasing variety of commercially available human DBMs from which to choose. Yet, there is limited information on a specific DBM product's osteoinductive efficacy, potency, and constancy. METHODS: There were protein extracts from each DBM sample separately dialyzed 4 times against distilled water at 4 degrees C for 48 hours. The amount of BMP-2, BMP-4, and BMP-7 was determined using enzyme-linked immunosorbent assay. RESULTS.: The concentrations of detected BMP-2 and BMP-7 were low for all DBM formulations, only nanograms of BMP were extracted from each gram of DBM (20.2-120.6 ng BMP-2/g DBM product; 54.2-226.8 ng BMP-7/g DBM). The variability of BMP concentrations among different lots of the same DBM formulation, intra-product variability, was higher than the variability of concentrations among different DBM formulations, inter-product variability (coefficient of variation range BMP-2 [16.34% to 76.01%], P < 0.01; BMP-7 [3.71% to 82.08%], P < 0.001). BMP-4 was undetectable. CONCLUSIONS: The relative quantities of BMPs in DBMs are low, in the order of 1 x 10(-9) g of BMP/g of DBM. There is higher variability in concentration of BMPs among 3 different lots of the same DBM formulation than among different DBM formulations. This variability questions DBM products' reliability and, possibly, efficacy in providing consistent osteoinduction.

Biological Products↗
PubMed2006

Controlling bone morphogenetic protein diffusion and bone morphogenetic protein-stimulated bone growth using fibrin glue.

STUDY DESIGN: An in vitro and in vivo study. OBJECTIVE: To evaluate the ability of fibrin glue to limit diffusion of recombinant human bone morphogenetic protein (rhBMP)-2 and its ability to protect spinal nerves from rhBMP-2 stimulated bone growth. SUMMARY OF BACKGROUND DATA: Studies have shown bone morphogenetic protein (rhBMP-2) stimulated bone growth can encroach on the spinal canal and nerves, causing neural compression. More recently, rhBMP-2 use in the cervical spine has been associated with life-threatening swelling. Fibrin glue has been used as a biologic carrier but has not been evaluated for its ability to limit rhBMP-2. METHODS: In phase 1 of the study, rhBMP-2 soaked absorbable collagen sponges (ACS) were encapsulated in fibrin glue and immediately incubated in physiologic lactated ringers solution at 38 degrees C. Samples of solution were tested for rhBMP-2 concentration. In phase 2 of the study, rats were surgically treated with laminectomy and placement of rhBMP-2/ACS versus laminectomy and placement of fibrin glue before placement of rhBMP-2/ACS. After 8 weeks, animals were euthanized and imaged using micro-computerized tomography. RESULTS: The diffusion study showed a significant limitation in rhBMP-2 diffusion when encapsulated in fibrin glue. The laminectomy study revealed blockage of bone formation by fibrin glue and protection of the spinal canal. CONCLUSIONS: Fibrin glue can limit the diffusion of rhBMP-2, and, thus, it can be used to help protect the spinal canal and nerve roots from rhBMP-2 stimulated bone growth.

Animals↗
PubMed2006

Graft resorption with the use of bone morphogenetic protein: lessons from anterior lumbar interbody fusion using femoral ring allografts and recombinant human bone morphogenetic protein-2.

STUDY DESIGN: This is a prospective cohort study examining the results and radiographic characteristics of anterior lumbar interbody fusion (ALIF) using femoral ring allografts (FRAs) and recombinant human bone morphogenetic protein-2 (rhBMP-2). This was compared to a historical control ALIF using FRAs with autologous iliac crest bone graft (ICBG). OBJECTIVE: To determine whether the use of rhBMP-2 can enhance fusion ALIF with stand-alone FRAs. SUMMARY OF BACKGROUND DATA: ALIF is a well-accepted procedure in reconstructive spine surgery. Advances in spinal surgery have produced a multitude of anterior interbody implants. The rhBMP-2 has promoted fusion in patients undergoing ALIF with cages and threaded allograft dowels. The FRA still remains a traditional alternative for anterior support. However, as a stand-alone device, the FRA has fallen into disfavor because of high rates of pseudarthrosis. With the advent of rhBMP-2, the FRA may be more attractive because of its simplicity and remodeling potential. It is important to understand the implications when rhBMP-2 is used with such structural allografts. METHODS: A total of 36 consecutive patients who underwent ALIF with stand-alone FRAs by a single surgeon (E.G.D.) at 1 institute were included. A cohort of 9 consecutive patients who received FRAs filled with rhBMP-2 was followed prospectively. After noticing suboptimal results, the senior author terminated this method of lumbar fusion. A total of 27 prior consecutive patients who received FRAs filled with autogenous ICBG were used for comparison. Analyzing sequential radiographs, flexion-extension radiographs, and computerized tomography with multiplanar reconstructions determined nonunions. Minimum follow-up was 24 months. RESULTS: Pseudarthrosis was identified in 10 of 27 (36%) patients who underwent stand-alone ALIF with FRAs and ICBG. Nonunion rate was higher among patients who received FRAs with rhBMP-2 (i.e., 5 of 9 [56%]). Statistical significance was not established because of the early termination of the treatment group (P > 0.3). Of interest, radiographs and computerized tomography revealed early and aggressive resorption of the FRAs when used with rhBMP-2. This preceded graft fracture and even disintegration, resulting in instability and eventual nonunion. CONCLUSION: The use of rhBMP-2 did not enhance the fusion rate in stand-alone ALIF with FRAs. In fact, the trend was toward a higher nonunion rate with rhBMP-2, although this was not significant with the numbers available. This result appears to be caused by the aggressive resorptive phase of allograft incorporation, which occurs before the osteoinduction phase.

Adult↗
PubMed2006

Computed tomography assessment of the accuracy of in vivo placement of artificial discs in the lumbar spine including radiographic and clinical consequences.

STUDY DESIGN: Prospective cohort study of 52 patients who had undergone artificial lumbar disc replacement. OBJECTIVES: To evaluate the implantation accuracy of prosthesis positioning, subsequent facet joint changes and prosthesis migration, and the clinical consequences of implant position. SUMMARY OF BACKGROUND DATA: Accuracy of spinal prosthesis implantation has not been evaluated rigorously, especially with a mini-incision approach. It is unknown if the inexact placement of a mobile device in the spine has any biomechanical, radiographic, or clinical repercussions. METHODS: A total of 52 consecutive patients were treated using standard methods of disc implantation with an intervertebral prosthesis. Computed tomography scans were performed within 3 days and again at 6 to 24 months. An independent radiologist analyzed the images for prosthesis position, rotation, migration, and facet changes. Results were compared with clinical outcome, measured by the Visual Analog Scale and Oswestry Disability Index. RESULTS: Deviation of the prosthesis from the center position was under 1.2 mm, and rotation off of midline was under 12 degrees. Follow-up CT scans showed no migration or facet changes. Regression analysis showed no correlation of prosthesis position with clinical outcome. CONCLUSIONS: Current prosthetic disc implantation methods, with minimally invasive access techniques, are relatively accurate. Although there can be deviation of the prosthesis from ideal placement, no repercussions were attributable.

Adult↗
PubMed2006

Kyphoplasty reduction of osteoporotic vertebral compression fractures: correction of local kyphosis versus overall sagittal alignment.

STUDY DESIGN: A retrospective study of patients who underwent 1-3-level kyphoplasty procedures at a single institute. OBJECTIVE: To examine and compare the effects of single and multilevel kyphoplasty procedures on local versus overall sagittal alignment of the spine. SUMMARY OF BACKGROUND DATA: Cement augmentation has been a safe and effective method in the treatment of symptomatic vertebral compression fractures (VCFs). In addition to providing rapid pain relief, balloon tamp kyphoplasty has reduced acute fractures, allowed controlled cement placement under lower pressure, and resulted in improvement of deformity. The restoration of normal overall spinal sagittal alignment in the elderly patient with a VCF and kyphotic deformity has obvious benefits. Although significant correction of local kyphosis (fractured vertebra) has been reported in the literature, to our knowledge, there have been no reports on whether this leads to an improved overall sagittal alignment. METHODS: A total of 65 consecutive patients with symptomatic VCFs who underwent 1-3-level kyphoplasty procedures were included in the study. Preoperative and postoperative radiographs were analyzed to quantify local and overall spinal sagittal alignment correction. Preoperative and postoperative vertebral heights at the fractured levels were also measured and categorized into anterior, middle, or posterior vertebral heights. RESULTS: Measurements revealed that kyphoplasty reduced local kyphotic deformity at the fractured vertebra by an average of 7.3 degrees (63% of preoperative kyphosis). This result did not translate to similar correction in overall sagittal alignment. In fact, angular correction decreased to 2.4 degrees (20% of preoperative kyphosis at fractured level) when measured 1 level above and below. The angular correction further decreased to 1.5 degrees and 1.0 degrees (13% and 8% of preoperative kyphosis at fractured level), respectively, at spans of 2 and 3 levels above and below. Average height gain was highest in the middle of the vertebral body (39% increase) compared to the anterior or posterior edges (19% and 3% increases, respectively). With multilevel kyphoplasty procedures, higher angular gains were seen over more vertebrae compared to the 7.3 degrees for a single-level kyphoplasty: 7.8 degrees over 2 levels and 7.7 degrees over 3 levels for 2 and 3-level kyphoplasty procedures, respectively. Kyphoplasty was able to achieve higher angular reduction in thoracic versus lumbar fractures (8.5 vs. 6.4 degrees, P < 0.01). The angular correction was also better maintained over adjacent segments in the thoracic spine. CONCLUSION: The majority of kyphosis correction by kyphoplasty is limited to the vertebral body treated. The majority of height gained after kyphoplasty occurs in the midbody. Higher correction over longer spans of the spine can be achieved with multilevel kyphoplasty procedures, in proportion to the number of levels addressed. Notwithstanding its well-published clinical efficacy, it is unrealistic to expect a 1 or 2-level kyphoplasty to improve significantly the overall sagittal alignment after VCFs.

Aged↗
PubMed2005

An outcomes analysis of the treatment of cervical pseudarthrosis with posterior fusion.

STUDY DESIGN: A retrospective review of 33 consecutive patients treated with posterior fusion and selective nerve root decompression for the treatment of pseudarthrosis following anterior cervical discectomy and fusion. OBJECTIVES: Use standardized outcome measures to evaluate the results of posterior fusion with selective nerve root decompression as a treatment option for symptomatic pseudarthrosis of the cervical spine. SUMMARY OF BACKGROUND DATA: Pseudarthrosis after anterior cervical discectomy and fusion has been recognized as a cause of continued cervical pain and unsatisfactory outcomes. Debate continues as to whether a revision anterior approach or a posterior fusion procedure is the best treatment for symptomatic cervical pseudarthrosis. To our knowledge, standardized outcome measures have not been used to evaluate the results of either surgical treatment option; therefore, it is difficult to evaluate outcomes in these patients, let alone compare surgical treatment options. Data on fusion rates in these two surgical treatment groups suggest a trend of a higher fusion rate with utilization of a posterior revision procedure, but the largest study to date includes the study of only 19 patients treated with a posterior fusion. METHODS: Thirty-three consecutive patients with symptomatic pseudarthrosis following anterior cervical discectomy and fusion were treated with selective nerve root decompression and posterior fusion using iliac crest or local bone graft as well as posterior wiring and/or lateral mass plating. The average follow-up period was 46 months (range, 20-86 months). Patients were assessed using physical examination, flexion-extension lateral radiographs, and standardized outcome measures including the SF-36, Arthritis Impact Measurement Scales 2, and Cervical Spine Outcomes Questionnaire. RESULTS: All 33 patients (100%) demonstrated a solid fusion at their most recent follow-up, and all 33 patients noted significant improvement in their preoperative symptoms. No difference in fusion status was noted between those treated with iliac crest versus patients treated with local bone graft--all had a solid fusion; 72% of the patients were satisfied with the result of their surgery. Cervical Spine Outcomes Questionnaire pain scales demonstrated 52% of patients reported mild or nopain at follow-up, whereas 20% described their pain as "discomforting" and 28% of the patients continued to report moderate to severe pain. CONCLUSIONS: This is the first study to our knowledge to use standardized outcome measures to assess clinical outcome in patients treated with posterior fusion for pseudarthrosis after anterior cervical discectomy and fusion. Patients and surgeons need to understand the potential for success with this revision procedure but also be aware of the relatively high rate of continued moderate to severe pain observed in this patient population even after a solid fusion is achieved. All of the patients in this study fused with a single posterior fusion procedure, further supporting the relatively higher fusion rates observed in the literature using posterior fusion as a treatment for cervical pseudarthrosis. Our results also support the ability of surgeons to use local bone graft without iliac crest in a posterior fusion for cervical pseudarthrosis and therefore avoid the morbidity associated with iliac crest bone graft harvest.

Adult↗
PubMed2005

Clinical results of ProDisc-II lumbar total disc replacement: report from the United States clinical trial.

The much-awaited clinical use of lumbar artificial discs has begun in the United States. The United States Investigational Device Exemption (US IDE) clinical trial of the ProDisc-II prosthetic disc (Synthes, Paoli, PA) was recently completed, with all indications that it meets or surpasses the test of equivalence against fusion controls. This is a review of the clinical performance of the ProDisc-II artificial disc and includes an interim report from the US IDE trial at one site.

Adult↗
PubMed2004

The IDET procedure for chronic discogenic low back pain.

STUDY DESIGN: Retrospective study with independent evaluation of patient outcomes approximately 1 year post-intradiscal electrothermal therapy (IDET). OBJECTIVE.: To assess functional status, symptoms, and subsequent treatments of patients treated with IDET. SUMMARY OF BACKGROUND DATA: IDET was introduced as a procedure for discogenic pain. Several studies reported improvement in >70% of patients. METHODS: Seventeen physicians referred 60 patients. Each patient had a positive discogram and had been treated with IDET. Patients were contacted approximately 1 year post-IDET, answered a telephone interview, and completed a self-administered questionnaire. Overall patient satisfaction, pain, functional and work status, analgesic usage, and subsequent treatments were noted. Kaplan-Meier survival curve was generated to predict the percentage that would undergo lumbar surgery after IDET. RESULTS: Average age was 40 years (range 25-64 years) with 66% males and 34% females. Of the 44 patients who responded, 6 patients had a lumbar surgery within 1 year. Their outcomes were excluded from descriptive analysis; 97% continued to have back pain, 11 (29%) reported more pain post versus pre-IDET, 15 (39%) had less pain, and 11 (29%) reported no change; 11 (29%) reported using more pain medication post-IDET, 10 (26%) used the same, 12 (32%) used less, and 5 (13%) used none; 19 (50%) were dissatisfied with IDET, 14 (37%) were satisfied, and 5 (13%) were undecided; 20 (53%) would have the procedure again, 12 (31%) would not, and 6 (16%) were unsure. Most patients wore a brace >6 hours/day after surgery (duration 1-15 months). Sixteen (42%) were employed full-time pre-IDET and 11 (29%) were employed full-time post-IDET. CONCLUSION: At 1-year post-IDET, half of patients were dissatisfied with their outcome. The percentage of patients on disability remained constant. The estimated proportion of patients undergoing fusion was predicted to be 15% at 1 year and 30% at 2 years.

Adult↗
PubMed2004

Adjacent two-level lumbar discectomy: outcome and SF-36 functional assessment.

STUDY DESIGN: A retrospective outcomes study. OBJECTIVES: To examine the outcome following adjacent two-level lumbar discectomy using both surgeon-based evaluation criteria and validated patient-based quality of life instrument (SF-36). SUMMARY OF BACKGROUND DATA: Lumbar discectomies have documented success rates between 49% and 98% for single-level procedures. However, no prior study has specifically examined the outcome following adjacent two-level lumbar discectomy in a large series of patients. METHODS: This study analyzed 55 patients with a minimum 2-year follow-up. All patients underwent adjacent two-level lumbar discectomy for radicular pain attributable to nerve root impingement at the corresponding levels. The patients were divided into two diagnostic groups based on their preoperative radiographic studies. Patients with two-level adjacent posterolateral lumbar disc herniations without concomitant osseous degenerative changes at the same levels constituted Group 1 (22 patients). Patients with associated osseous degenerative changes at the same levels made up Group 2 (33 patients). The patients' clinical outcome was assessed using the MacNab classification and SF-36 questionnaire. RESULTS: The average duration of follow-up was 41 months (range 24-96 months). The group consisted of 35 males and 20 females with average age of 49 years (range 19-82 years). Excellent results were observed in 49%, good in 20%, fair in 15%, and poor in 16%. However, patients in Group 1 have 86% excellent/good results, whereas patients in Group 2 have 57% excellent/good results. Overall, 15% of the patients required reoperation and subsequent spinal fusion. Analysis of the SF-36 scores revealed significant differences based on patient's diagnostic grouping as well. Patients in Group 1 have physical and mental summary scores comparable with age- and sex-adjusted population norms and significantly higher than those in Group 2 (P < 0.01). CONCLUSIONS: Two-level discectomy is an effective treatment with clinical outcome comparable with single-level discectomy. Patients with posterolateral disc herniations and definitive radiculopathy without osseous degenerative changes at the same levels have better clinical outcome and quality of life scores compared with those patients having concomitant degenerative arthritis at the same levels. Patients having two-level discectomy may be at increased risk of requiring subsequent lumbar fusion compared with those with single-level discectomy.

Adult↗
PubMed2004

Left iliac artery thrombosis during anterior lumbar surgery.

To determine the incidence of left iliac artery thrombosis (LIAT), a prospective database was maintained on 1315 patients undergoing anterior lumbar surgery (ALS) between August 1997 and December 2002. All had distal pulse evaluation preoperatively. In the last 629 cases pulse oxymetry was used to monitor the distal circulation during and after surgery. Patients with pulse deficits or evidence of ischemia after surgery were further analyzed. Six patients were identified with LIAT (0.45%). Five were females and one was male, with ages ranging from 35 to 56 years. All had exposure at the L4-5. Five were diagnosed at surgery and one in the recovery room after posterior surgery. All except one had strong, palpable preoperative pulses. Pulse oxymetry confirmed the diagnosis in two patients, in whom it was not clinically evident. Four had successful thrombectomy; one had a femoro-femoral bypass and one had an axillo-femoral bypass. Two developed compartment syndrome. None had calcifications on preoperative X-rays. LIAT is an uncommon complication of ALS. Early identification and management can avoid long-term complications. Pulse oxymetry helps in its timely identification. Patients undergoing exposure at L4-5 and females are at greater risk.

Adolescent↗
PubMed2003

ProDisc artificial total lumbar disc replacement: introduction and early results from the United States clinical trial.

STUDY DESIGN: Multicenter prospective randomized study of artificial disc replacement (ProDisc) versus circumferential fusion (standard of care) for one- and two-level degenerative disc disease. This is an interim analysis on patients seen at the Spine Institute Saint John's Health Center, Santa Monica, California. OBJECTIVES: To evaluate early pain and functional outcomes of patients treated with disc replacement or fusion and to assess the capacity of this intervertebral disc replacement for preserving motion in the lumbar spine. SUMMARY OF BACKGROUND DATA: Disc replacement is intended to reduce pain via removal of the diseased disc while restoring physiologic motion and height at the affected level. The long-term physiologic advantage of disc replacement to fusion is that preservation of motion may prevent additional degeneration at adjacent levels. METHODS: Patients meeting inclusion criteria were consented for study. Randomization was performed using a 2 to 1 ratio of disc replacement procedure to a fusion procedure. Patients rated their pain on the Visual Analogue Scale and completed the Oswestry Disability Index questionnaire. Radiographs were taken. Assessments were made before surgery and after surgery at 6 weeks, 3 months, 6 months, and 1 year (ongoing). Changes from preoperative pain, disability, or motion were separately evaluated as a function of treatment using repeated measures mixed design analysis of variance. RESULTS: This analysis includes data up to 6 months from the first 53 randomized patients. There were 35 patients who underwent disc replacements, and 18 patients had fusion procedures. Disc replacement patients had a significant reduction in pain and disability at earlier evaluations. By 6 months, the relative improvement on both the Visual Analogue Scale and Oswestry (both, P < 0.05) were similar for disc replacement and fusion patients. Greater motion was found at L4-L5 for disc replacement patients (P < 0.05) than fusion patients. A similar trend was noted at L5-S1 (P was not significant). CONCLUSIONS: Disc replacement patients reported significantly less pain (Visual Analogue Scale) and disability (Oswestry) in the early period following surgery compared to fusion patients. This difference disappeared by 6 months. When compared to fusion, the disc replacement allowed preservation of motion at L4-L5 with a similar trend at L5-S1.

Adult↗
PubMed2003

Perioperative complications of threaded cylindrical lumbar interbody fusion devices: anterior versus posterior approach.

Few data are available to evaluate approach-related differences in perioperative complications with lumbar interbody fusion devices. Complications occurring in the intraoperative and immediate postoperative period were identified and categorized for 31 consecutive posterior lumbar interbody fusions (PLIFs) and 88 consecutive anterior lumbar interbody fusions (ALIFs). In this study, all lumbar interbody fusions were conducted with threaded cylindrical devices as stand-alone internal fixation devices. Multivariate analysis was used to account for potential covariates and identify factors associated with an increased complication risk. Twenty-two percent of the patients had a perioperative complication. The relative risk of having a perioperative complication was 4.75 times higher for the PLIF group. All intraoperative complications occurred in the PLIF group. The relative risk of having a major postoperative complication was 6.8 times higher in the PLIF group than the ALIF group. Anterior approached patients tended to have visceral (ileus, 6%) and vascular (deep venous thrombosis, 2%) complications. In the posterior group, complications were neurologic and dura related (pseudomeningocele, 16%; epidural hematoma, 3%) and occurred most frequently in patients that had had previous posterior lumbar surgery (31% with major complication).

Adult↗
PubMed2003

Microsurgery for degenerative conditions of the cervical spine.

Although the operating microscope has been used for spine surgery for more than 20 years, its use is still not widely accepted by orthopaedic spine surgeons. Nevertheless, surgeons who have used the operating microscope are well aware of its many advantages in performing spine surgery. Most notably, the superior visualization it provides allows for faster, safer, and more extensive decompressions. The reluctance of many surgeons to use the operating microscope often has to do with trepidation regarding new technology. The use of the operating microscope when performing anterior and posterior cervical spine surgery makes these procedures easier to carry out and decreases the risk of complications during decompression of the spinal cord.

Cervical Vertebrae↗
PubMed2002

Low back pain recollection versus concurrent accounts: outcomes analysis.

STUDY DESIGN: Patients with low back pain were asked to recall the pain and impaired functioning that they reported 5-10 years previously as part of the National Low Back Pain prospective follow-up study. In 1998, patients completed an additional follow-up. OBJECTIVES: To compare outcomes using patient-recalled data and prospectively collected data from patients with low back pain and to identify simple, symptom-specific questions that yield reliable responses over an extended period of time. SUMMARY OF BACKGROUND DATA: Outcome assessment based on patient recall may be influenced by a patient's age, gender, reporting tendency, and current health status. The impact of data collected retrospectively on outcome analyses in spinal patients has not been addressed. METHODS: Patients enrolled in the National Low Back Pain study from 1986 to 1991 completed a self-administered questionnaire at their initial visit. A sample was interviewed by telephone in 1996 and asked to recall pain characteristics and impaired functioning reported at initial examination. A 10-year follow-up (1998) on current health status was conducted by mail. The 1998 follow-up response was separately compared with recalled and initial responses, such that two patient outcome status values were calculated for each question. Agreement was evaluated using Cohen's kappa. RESULTS: The follow-up evaluation was completed by 144 patients, with a mean interval of 9.4 years. The overall simple kappa was 0.37, indicating "fair" agreement between outcomes based on initial and recalled accounts of pain. Questions on location of pain had kappa values of 0.12-0.58, radicular symptoms 0.28-0.48, and severity of pain 0.11-0.30. CONCLUSIONS: "Fair" to "moderate" agreement was found between outcomes determined by recalled versus initial reports. Accuracy was greatest for queries on frequency, location of pain, and activities affecting pain. Discrepancies were noted for queries on severity of pain, with error bias toward less pain when using the recalled data. Careful selection of questions may yield more accurate outcome measures.

Adult↗
PubMed2002

Single-level lumbar spine fusion: a comparison of anterior and posterior approaches.

This study is a retrospective review of 122 patients who underwent single-level lumbar spine fusion. The objectives were to directly compare perioperative morbidity and early results of single-level anterior interbody posterolateral intertransverse process lumbar spine fusion and to provide objective findings that may be useful in selecting surgical method. Lumbar spinal fusion is a well-recognized surgical treatment of intractable low back pain resulting from DDD or spondylolisthesis. Assessments of techniques, results, and outcomes have been published, but detailed head-to-head comparisons of anterior posterior approaches with objective operative and postoperative data are not available in the literature. A retrospective review of 122 patients who underwent either an anterior interbody or posterolateral intertransverse process (average follow-up 22 and 26 months, respectively) single-level instrumented lumbar spinal fusion was performed. Surgical, perioperative, and follow-up data were obtained directly from medical records. The findings compared included estimated blood loss, need for blood transfusion, number of units transfused, operative time, number of days in hospital, need for transitional facility care, complications, need for further surgery, radiographic fusion, and clinical results. There was significantly less blood loss, need for transfusion, amount of blood transfused, operative time, and hospital stay for patients with anterior fusion procedures (p < 0.01). There was no significant difference in need for transitional facility care, complication rates, and given follow-up period in radiographic fusion rate and clinical outcome. Clinical results were significantly worse for those undergoing revision primary fusion (p < 0.01). The anterior approach to single-level lumbar fusion is associated with less morbidity than the posterolateral approach. This may in turn affect surgical outcome and hospital cost. However, both approaches to single-level lumbar fusion produce similar early fusion rates and clinical results. Revision fusions had poor early results regardless of approach.

Adult↗
PubMedDate not supplied

Vascular injury during anterior lumbar surgery.

BACKGROUND CONTEXT: With the number of anterior lumbar procedures expected to increase significantly over the next few years, it is important for spine surgeons to have a good understanding about the incidence of vascular complications during these operations. PURPOSE: To determine the incidence of vascular injury in 1,315 consecutive cases undergoing anterior lumbar surgery at various levels from L2 to S1. STUDY DESIGN/SETTING: Patients undergoing anterior lumbar surgery were studied. PATIENT SAMPLE: A total of 1,310 consecutive patients undergoing 1,315 anterior lumbar procedures between August 1997 and December 2002 were included in the study. OUTCOME MEASURES: All patients were evaluated for incidence of vascular injury during and immediately after surgery. METHOD: A concurrent database was maintained on all these cases. All the patients had distal pulse evaluation preoperatively. Patients with venous injuries were further analyzed to determine location and extent of injury, amount of blood loss, completion of the procedure and postoperative sequelae. Patients with pulse deficits or evidence of ischemia during or immediately after surgery were further analyzed in particular in relation to demographic, preoperative variables and management. RESULTS: Six patients were identified as having left iliac artery thrombosis (0.45%), and 19 had major vein lacerations (1.4%). CONCLUSION: This study shows that the incidence of vascular injury is relatively low (25 in 1,315 or 1.9%). Because only five of these patients experienced significant sequelae from the approach, it appears that anterior lumbar surgery is quite safe, although it must be carried out with utmost respect for the vessels to avoid possible catastrophic outcomes.

Cohort Studies↗
PubMedDate not supplied

An in vitro and in vivo analysis of fibrin glue use to control bone morphogenetic protein diffusion and bone morphogenetic protein-stimulated bone growth.

BACKGROUND CONTEXT: Recombinant human bone morphogenetic protein-2 (rh-BMP2) has become popular for augmenting spine fusion in the lumbar and cervical spine. Concerns exist, however, over bone morphogenetic protein (BMP)-stimulated soft-tissue swelling and bone growth stimulation in areas where bone is not desired, especially as the material "leaks" into such spaces. The most detrimental effects of such leakage might be airway compromise, while heterotopic bone formation into the spinal canal has been reported in animal and human studies. Fibrin glue has been used as a carrier of many osteoinductive materials; however, its efficacy at modulating the clinical effects of BMP are not known. The amorphous nature of fibrin glue makes it a candidate to control diffusion of BMP and possibly limit bone formation by limiting BMP diffusion to areas where such bone is not desired. PURPOSE: To evaluate the use of fibrin glue to limit BMP diffusion and BMP-stimulated bone growth. STUDY DESIGN/SETTING: This is an in vitro basic science study and an in vivo prospective randomized animal study. STUDY SAMPLE: Eighteen Lewis rats. OUTCOME MEASURES: In vitro study: Enzyme-linked immunosorbent assay measurement of rh-BMP2 concentration in saline. In vivo study: At day 60, rats were evaluated for neurologic deficits before sacrifice. Spines were harvested, and the following studies were performed: 1) manual testing for fusion and bone growth; 2) X-ray evaluation; 3) Micro-computed tomography (micro-CT) scans. METHODS: In vitro study: Collagen sponges soaked with BMP at two different concentrations were incubated in saline solution with and without encapsulation by fibrin glue. Saline BMP concentrations were measured at consecutive time points. In vivo study: A rat fusion model using rh-BMP2 for fusion has been developed and tested with resultant100% fusion in over 100 rats. Lewis rats were divided into two groups and treated as follows: I: Exposure of L4-L5 transverse processes, decortication, and placement of BMP sponge in the lateral intertransverse space. II: Exposure and decortication as above and placement of fibrin glue before BMP sponge placement. RESULTS: In vitro study: Peak rh-BMP2 concentrations in saline were 20% and 45% of the maximum possible for fibrin glue encapsulated sponges and controls, respectively, with a more gradual increase to peak concentration in samples encapsulated in fibrin glue. In vivo study: No rats exhibited any neurologic deficits. X-rays revealed at least partial bone formation in all rats. Manual testing of intertransverse fusion spines revealed 100% fusion in rats treated with BMP only, whereas rats treated with fibrin glue before placement of BMP sponges revealed only one possible fusion. Posterior-lateral bone formation was present on X-ray in both groups, and micro-CT imaging revealed bridging bone from transverse processes to the BMP-stimulated bone in the control groups. In spines treated with fibrin glue before rh-BMP2 placement, bone formation could still be seen within the soft tissues; however, bridging bone connecting to the transverse processes was either significantly decreased or not present. CONCLUSIONS: Fibrin glue can limit rh-BMP2 diffusion. Also, because it limited bone formation at the transverse processes, it can be inferred that fibrin glue can limit bone formation when used to separate areas of desired bone formation from areas where bone formation is not desired.

Animals↗