Ben B Pradhan

Saint John's Health Center, Santa Monica, California, United States

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Publications (22)47.86 Total impact

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    ABSTRACT: Traditional posterior pedicle screw fixation is well established as the standard for spinal stabilization following posterior or posterolateral lumbar fusion. In patients with lumbar spinal stenosis requiring segmental posterior instrumented fusion and decompression, interlaminar lumbar instrumented fusion (ILIF) is a potentially less invasive alternative with reduced morbidity and includes direct decompression assisted by an interlaminar allograft spacer stabilized by a spinous process plate. To date, there has been no biomechanical study on this technique. In the present study the biomechanical properties of the ILIF construct were evaluated using an in vitro cadaveric biomechanical analysis, and the results are presented in comparison with other posterior fixation techniques. Eight L1-5 cadaveric specimens were subjected to nondestructive multidirectional testing. After testing the intact spine, the following conditions were evaluated at L3-4: bilateral pedicle screws, bilateral laminotomy, ILIF, partial laminectomy, partial laminectomy plus unilateral pedicle screws, and partial laminectomy plus bilateral screws. Intervertebral motions were measured at the index and adjacent levels. Bilateral pedicle screws without any destabilization provided the most rigid construct. In flexion and extension, ILIF resulted in significantly less motion than the intact spine (p < 0.05) and no significant difference from the laminectomy with bilateral pedicle screws (p = 0.76). In lateral bending, there was no statistical difference between ILIF and laminectomy with unilateral pedicle screws (p = 0.11); however, the bilateral screw constructs were more rigid (p < 0.05). Under axial rotation, ILIF was not statistically different from laminectomy with unilateral or bilateral pedicle screws or from the intact spine (p > 0.05). Intervertebral motions adjacent to ILIF were typically lower than those adjacent to laminectomy with bilateral pedicle screws. Stability of the ILIF construct was not statistically different from bilateral pedicle screw fixation following laminectomy in the flexion and extension and axial rotation directions, while adjacent segment motions were decreased. The ILIF construct may allow surgeons to perform a minimally invasive, single-approach posterior decompression and instrumented fusion without the added morbidity of traditional pedicle screw fixation and posterolateral fusion.
    Journal of neurosurgery. Spine 04/2012; 16(6):585-93. · 1.61 Impact Factor
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    ABSTRACT: Retrospective review. To evaluate the effect of postoperative use of ketorolac (Toradol) on spinal fusion in humans. The value of parenteral ketorolac in postoperative analgesia has been well documented across surgical specialties. However, some studies have shown that ketorolac may adversely affect osteogenic activity and fracture healing. A total of 405 consecutive patients who underwent primary lumbar posterolateral intertransverse process fusion with pedicle screw instrumentation were included in this retrospective study. A subtotal of 228 patients received Toradol after surgery for adjunctive analgesia. Each patient received a mandatory dose of 30 mg intravenously every 6 hours for 48 hours. The same surgeon performed the fusion procedure on all of these patients. Historical controls included 177 patients who did not receive Toradol after surgery. The minimum follow-up period was 24 months. Nonunions were diagnosed by analyzing sequential radiographs, flexion-extension radiographs, and computed tomography with multiplanar reconstructions. The gold standard of surgical exploration was performed in symptomatic patients with diagnostic ambiguity or nonunions diagnosed by imaging. There were no smokers in the study population. Pseudarthrosis was identified in 12 of 228 patients (5.3%) who received Toradol after surgery, and in 11 of 177 patients (6.2%) who did not. There was no significant difference detected in the nonunion rates between the two groups (P > 0.05, chi2 method). Use of ketorolac after spinal fusion surgery in humans, limited to 48 hours after surgery for adjunctive analgesia, has no significant effect on ultimate fusion rates.
    Spine 09/2008; 33(19):2079-82. · 2.45 Impact Factor
  • Ben B. Pradhan, Justin S. Field
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    ABSTRACT: Intraoperative fluoroscopy has become increasingly popular because of its potential to enhance the safety and efficacy of various surgical procedures while minimizing the risk of complications. The use of this imaging modality has already been documented for a number of spinal applications including decompression of the neural elements and the placement of instrumentation. Fluoroscopic visualization may be particularly well-suited for minimally invasive approaches such as the insertion of percutaneous pedicle screws and vertebral body augmentation. The objective of this report is to present the state-of-the-art fluoroscopic techniques that have been described for the surgical management of spinal pathology.
    Seminars in Spine Surgery 09/2008; 20(3):168-174.
  • Hyun Bae, Ben Pradhan, Rick Delamarter
    The Spine Journal 09/2008; 8(5):184S-185S. · 2.80 Impact Factor
  • Spine 09/2008; · 2.45 Impact Factor
  • Ben B Pradhan
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    ABSTRACT: The management of chronic low back pain (CLBP) has proven very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence-Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.
    The Spine Journal 01/2008; 8(1):253-7. · 2.80 Impact Factor
  • Ben B. Pradhan, Rick B. Delamarter
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    ABSTRACT: This section describes the various imaging modalities that exist today for evaluating bone density and thereby diagnosing osteopenia or osteoporosis. Osteoporosis is the most common metabolic abnormality of the bone, and fragility fractures due to osteoporosis have a tremendous impact in our aging society. Dual-energy X-ray absorptiometry scans, digital X-ray radiogrammetry, quantitative computed tomography, quantitative ultrasound, and magnetic resonance imaging are discussed in some detail. While the evaluation of bone density is important in any surgical treatment of the spine that involves decompression (which may remove some stabilizing tissues, imparting a greater load on remaining bony elements) or instrumentation (that depend on implant-bone fixation), the biggest clinical impact these imaging modalities have is in the diagnosis and subsequent management of osteoporotic vertebral compression fractures, which is the most common fracture of fragility that affects the elderly population.
    Seminars in Spine Surgery 06/2007; 19(2):113-117.
  • The Spine Journal 09/2006; 6(5):101S. · 2.80 Impact Factor
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    ABSTRACT: 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. To evaluate the use of fibrin glue to limit BMP diffusion and BMP-stimulated bone growth. This is an in vitro basic science study and an in vivo prospective randomized animal study. Eighteen Lewis rats. 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. 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. 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. 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.
    The Spine Journal 07/2006; 6(4):397-403; discussion 404. · 2.80 Impact Factor
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    ABSTRACT: An in vitro and in vivo study. 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. 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. 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. 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. 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.
    Spine 06/2006; 31(11):1201-6. · 2.45 Impact Factor
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    ABSTRACT: Prospective cohort study of 52 patients who had undergone artificial lumbar disc replacement. To evaluate the implantation accuracy of prosthesis positioning, subsequent facet joint changes and prosthesis migration, and the clinical consequences of implant position. 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. 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. 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. 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.
    Spine 05/2006; 31(8):948-53. · 2.45 Impact Factor
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    ABSTRACT: 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). To determine whether the use of rhBMP-2 can enhance fusion ALIF with stand-alone FRAs. 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. 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. 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. 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.
    Spine 05/2006; 31(10):E277-84. · 2.45 Impact Factor
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    ABSTRACT: A retrospective study of patients who underwent 1-3-level kyphoplasty procedures at a single institute. To examine and compare the effects of single and multilevel kyphoplasty procedures on local versus overall sagittal alignment of the spine. 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. 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. 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. 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.
    Spine 03/2006; 31(4):435-41. · 2.45 Impact Factor
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    ABSTRACT: This is a brief review of selected spine literature evaluating the osteogenic potential of bone marrow derived cells in vivo. There is support for a slight increase in fusion rates attributable to the addition of autologous bone marrow aspirate in graft insufficiency experiments performed in animals. There is less support for the addition of bone marrow aspirate as an isolated osteogenic source of cells or inductive agent in merely conductive matrices or carriers. To date, a definitive clinical study demonstrating the efficacy of autologous bone marrow aspirate as a graft enhancer does not exist.
    Seminars in Spine Surgery 03/2006; 18(1):2-11.
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    ABSTRACT: Foot problems are common in patients with Marfan syndrome because of the ligamentous laxity that affects the weightbearing joints most. Such patients frequently are seen by their general practitioners or podiatrists. Educating primary health care providers about a metatarsal index, if it is sufficiently sensitive and specific, may help patients get early and appropriate workup for connective tissue disorders. A metatarsal equivalent to the metacarpal index (MCI) in the hand was evaluated as a diagnostic tool for Marfan syndrome (and possibly other connective tissue disorders). Fifty-six patients were studied. Sixteen had a genetic diagnosis of Marfan syndrome. There were 20 controls each for the MCI and the metatarsal index (MTI). Hand and foot radiographs were reviewed. The average MCI in patients with Marfan syndrome was 9.8 compared to 7.6 in the control group (p < 0.0005). The average MTI was 12.7 and 9.8, respectively (p < 0.0005). An MCI value of 8.5 and an MTI value of 10.5 had the best statistical profiles (combination of sensitivity and specificity) in diagnosing Marfan syndrome in our study population. The MTI as a screening tool for Marfan syndrome is as effective as, if not more than, the well-recognized MCI.
    Foot & Ankle International 10/2005; 26(10):881-5. · 1.63 Impact Factor
  • Rick B Delamarter, Hyun W Bae, Ben B Pradhan
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    ABSTRACT: 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.
    Orthopedic Clinics of North America 08/2005; 36(3):301-13. · 1.70 Impact Factor
  • The Spine Journal 07/2005; 5(4):S42–S43. · 2.80 Impact Factor
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    Ben B Pradhan, Dimple Bhasin, Wilfred Krom
    The Journal of Bone and Joint Surgery 04/2005; 87(3):635-8. · 4.31 Impact Factor
  • The Spine Journal 09/2004; 4(5). · 2.80 Impact Factor
  • The Spine Journal 09/2004; 4(5). · 2.80 Impact Factor

Publication Stats

317 Citations
47.86 Total Impact Points


  • 2005–2008
    • Saint John's Health Center
      Santa Monica, California, United States
  • 2007
    • Spine Institute Northwest
      Bothell, Washington, United States
  • 2002
    • University of California, Los Angeles
      • Department of Orthopaedic Surgery
      Los Angeles, CA, United States