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Biomedical subjects

Harvinder S Sandhu

Publications and source records attributed to Harvinder S Sandhu.

At least 19 recordsLinked to original sources
PubMed2006

Discordantly high spinal bone mineral density values in patients with adult lumbar scoliosis.

STUDY DESIGN: Retrospective study. OBJECTIVE: The purposes of this study were: 1) to investigate the validity of bone mineral density measurements with DEXA in patients with adult lumbar scoliosis and 2) to investigate the association between osteoporosis and adult lumbar scoliosis. SUMMARY OF BACKGROUND DATA: Osteoporosis and lumbar degenerative scoliosis are phenomena encountered with increased frequency in aging, often concurrently. It has been suggested that scoliosis predisposes to osteoporosis, but degenerative scoliosis could falsely elevate spinal bone mineral density measurements. METHODS: The feasibility of measuring Cobb's angle in DEXA scans was established in 48 surgical candidates with standing anteroposterior lumbar radiographs and supine DEXA scans. Charts and radiographs of 454 consecutive adult patients evaluated at an osteoporosis center were reviewed thereafter. The association between age, lumbar curve, and various bone density measurements was investigated. Bone density measurements between nonscoliotic and scoliotic patients with and without a history of adolescent scoliosis were compared. RESULTS: Cobb's angle on DEXA scan was measured with an error of 4 degrees and correlated highly with the plain lumbar radiographs. The prevalence of scoliosis was 9.47% in this cohort of patients. Advancing age was associated with an increase in osteoporosis in both scoliotic and nonscoliotic patients. Scoliotic patients demonstrated increased spinal bone mineral density (BMD) measurements compared with nonscoliotic patients, resulting in discrepancies between hip and spine BMD values. This discrepancy correlated with aging and curve magnitude (up to 30% for curves of 43 degrees ). Scoliotic patients demonstrated significantly lower hip BMD values than nonscoliotic. Curve magnitude did not correlate with severity of osteoporosis. CONCLUSIONS: Cobb's angle measurements on DEXA scans are reliable and comparable to conventional radiographs. Spinal BMD values are less valuable for monitoring osteoporosis than hip values in scoliotic patients; an increasing discrepancy with age was noted. Scoliotic patients exhibited discordantly high spinal BMD values, despite significant hip osteoporosis. The discrepancy correlated with aging and curve magnitude. Scoliosis was common among the osteoporotic population (9.47%). Lumbar scoliosis is a useful clinical marker for osteoporosis, irrespective of scoliosis history and magnitude. Viable alternatives for osteoporosis evaluation of adult patients with lumbar scoliosis are hip DEXA values, in conjunction with other BMD measurements.

Absorptiometry, Photon↗
PubMed2006

Outcome of revision discectomies following recurrent lumbar disc herniation.

STUDY DESIGN: Retrospective study. OBJECTIVES: To assess the difference in the outcome score between a primary surgery to treat lumbar disc herniation and a revision surgery for recurrent herniation at the same location with the use of a validated lumbar spine outcome instrument. SUMMARY OF BACKGROUND DATA: Paucity of studies comparing the results of revision discectomy for true recurrent disc herniation at the same location to that reported for primary discectomy. METHODS: A total of 27 patients who had undergone revision discectomies for recurrent lumbar disc herniations were surveyed to assess their clinical outcomes. Patients were compared with a control group of 30 matched patients who had undergone only a primary discectomy. The spine module of the MODEMS outcome instrument was used to evaluate the patients' satisfaction, their pain and functional ability following discectomy, as well as their quality of life. All patients were also asked whether they were improved or worsened with surgery. Those undergoing revision surgery were asked whether the improvement following the second surgery was more or less than the improvement following the first surgery. RESULTS: Improvement following the repeat discectomy was not statistically different from the improvement that occurred in patients who underwent just the primary operation. Differences in residual numbness/tingling in the leg and/or the foot as well as in frequency of back and/or buttock pain were identified. CONCLUSION: Based on patient derived outcome data using a validated instrument, revision discectomy is as efficacious as primary discectomy in selected patients.

Adult↗
PubMed2006

Influence of rhBMP-2 on the healing patterns associated with allograft interbody constructs in comparison with autograft.

STUDY DESIGN: A prospective, nonblinded, multicenter study. OBJECTIVE: To determine the patterns of allograft incorporation and new bone formation after ALIF using stand-alone threaded cortical allograft dowels with either autograft or rhBMP-2. SUMMARY OF BACKGROUND DATA: Accelerated healing patterns of allograft dowels have been reported in an animal study and a small human study of ALIF with rhBMP-2 and bone dowels. METHODS: We enrolled and randomly assigned 131 patients with lumbar spondylosis who were undergoing single-level ALIF with allograft dowels to either the investigational group who received rhBMP-2 (79 patients) or the control group who received autologous bone graft (52 patients). Independent radiologists used plain radiographs and computed tomography scans to evaluate fusion. Allograft incorporation was assessed using a modified Bridwell-Lenke scale, and changes in bone density within the adjacent vertebral bodies were monitored. RESULTS: At 12 months, all investigational patients had radiographic evidence of new bone formation and incorporation of the allografts into the adjacent vertebral endplates; there were no changes in fusion status at 24 months. Fusions were documented in 89% of patients in the control group at 12 months. The percentage declined to 81.5% at 24 months with 10% of the patients in the autograft group showing incomplete healing and 11% having no healing of the allograft dowels. On CT scans, 14 of the investigational patients (14 of 79; 18%) developed a transient, localized area of bone remodeling within the vertebral body adjacent to the allograft dowel. All were healed by 24 months. The transient appearance of these zones had no effect on clinical outcomes. No patient in the control group developed bone remodeling zones. CONCLUSION: We think that the use of rhBMP-2 is a promising method of facilitating allograft dowel incorporation and new bone formation in patients undergoing ALIF with allograft dowels.

Adult↗
PubMed2005

Alendronate inhibits spine fusion in a rat model.

STUDY DESIGN: A posterolateral lumbar fusion model in rats. OBJECTIVE: To study the effects of alendronate on posterolateral lumbar fusion in rats. SUMMARY OF BACKGROUND DATA: To our knowledge, there are no studies that show a significant inhibition of manual palpation-assessed spine fusion by alendronate. METHODS: A total of 75 Sprague-Dawley rats underwent intertransverse fusion with 7-tailbone autograft at L4-L5. Animals received saline (control), alendronate equivalent to human dose (dose1, 5 microg/kg/day), or 10 times the human dose (dose10, 50 microg/kg/day) via subcutaneous osmotic pumps starting the day of surgery. Eight weeks after surgery, animals were euthanized, and fusion was assessed by manual palpation. Radiographic area and optical density of fusion masses were calculated. Histomorphometry was used to assess the percentage area of fusion masses occupied by bone or marrow tissues. RESULTS: Manual palpation fusion rates were lower in alendronate groups (50% and 40%, respectively) than in the control group (95%, P = 0.002). Interobserver and intraobserver kappa values were high (0.97-1.00). There were dose-dependent and statistically significant (P < 0.001) increases in fusion mass area and optical density with increasing alendronate dose. Fusion masses in dose10 animals had significantly higher percent area of bone tissue (P = 0.01) and lower percent area of marrow elements (P < 0.001) when compared to control animals. CONCLUSIONS: Alendronate inhibits spine fusion in rats. Fusion masses in alendronate-treated animals appeared radiographically larger and denser than those in control animals despite lower fusion rates. Quantitative histomorphometry confirmed that alendronate inhibited bone graft resorption and incorporation. We recommend that patients undergoing spine arthrodesis should not take alendronate until fusion is achieved.

Alendronate↗
PubMed2005

Use of rhBMP-2 in combination with structural cortical allografts: clinical and radiographic outcomes in anterior lumbar spinal surgery.

BACKGROUND: Recombinant human bone morphogenetic protein-2 soaked into an absorbable collagen sponge (rhBMP-2/ACS) has been shown in a nonhuman primate study and in a pilot study in humans to promote new bone formation and incorporation of an allograft device when implanted in patients undergoing anterior lumbar interbody arthrodesis. However, a larger series with longer follow-up is needed to demonstrate its superiority to autogenous iliac crest bone graft. METHODS: Between 1998 and 2001, a two-part, prospective, randomized, multicenter study of 131 patients was conducted to determine the safety and efficacy of the use of rhBMP-2/ACS as a replacement for autogenous iliac crest bone graft in anterior lumbar spinal arthrodesis with threaded cortical allograft dowels. Patients were randomly assigned to a study group that received rhBMP-2/ACS or to a control group that received autograft. The clinical and radiographic outcomes were determined with use of well-established instruments and radiographic assessments. RESULTS: The patients in the study group had significantly better outcomes than the control group with regard to the average length of surgery (p < 0.001), blood loss (p < 0.001), and hospital stay (p = 0.020). Fusion rates were significantly better in the study group (p < 0.001). The average Oswestry Disability Index scores, Short-Form-36 physical component summary scores, and low-back and leg-pain scores were significantly better in the study group (p < 0.05). CONCLUSIONS: In patients undergoing anterior lumbar interbody arthrodesis with threaded allograft cortical bone dowels, rhBMP-2/ACS was an effective replacement for autogenous bone graft and eliminated the morbidity associated with graft harvesting.

Absorbable Implants↗
PubMed2004

Cervical epidural abscess after epidural steroid injection.

STUDY DESIGN: This is a case report of a cervical epidural abscess presenting with neurologic deficits after cervical epidural steroid injection. OBJECTIVE: To describe the presentation, diagnosis, treatment, and outcome of a rare complication of cervical epidural steroid injection. SUMMARY OF BACKGROUND DATA: Cervical epidural steroid injections are a commonly used modality in the treatment of cervical spine disease. Serious complications from the procedure are rare. There is only one previously reported case of cervical epidural abscess after cervical epidural injection in the literature. MATERIALS AND METHODS: A case of cervical epidural abscess after epidural steroid injection is presented and the relevant literature is reviewed. RESULTS: The patient had partial recovery of neurologic function within the first 24 hours after decompressive laminectomy, irrigation, and debridement. There were no perioperative complications. Intraoperative cultures permitted positive identification of the infecting organism and appropriate antibiotic selection. At 7-month follow-up, there was no recurrence of infection and the patient had recovered baseline neurologic function and neck pain status. CONCLUSIONS: Cervical epidural abscess is a rare but potentially devastating complication after epidural steroid injection. Neurologic compromise may occur. Timely diagnosis and appropriate treatment may result in good clinical outcomes.

Cervical Vertebrae↗
PubMed2004

The current status of lumbar total disc replacement.

Total disc replacement is an exciting technology that may one day replace fusion as the gold standard treatment for DDD, but it is currently an experimental procedure in the United States. Promising short- and mid-term results have been reported for TDR, but longer follow-up and randomized trials comparing TDR to fusion and nonsurgical treatment are needed to fully define the role of TDR in the spine surgeon's armamentarium. Short-term complication rates have been acceptably low, but in the long term the durability of TDR implants and the vertebral endplate will provide challenges. Finally, it is essential that practitioners understand that a limited subset of patients are good candidates for TDR and that indiscriminate application of this technology will result in poor outcomes.

Biomechanical Phenomena↗
PubMed2004

High-dose alendronate uncouples osteoclast and osteoblast function: a study in a rat spine pseudarthrosis model.

The effect of alendronate on osteoclast and osteoblast function was studied in a novel spine pseudarthrosis model in rats. Sixty-three Sprague-Dawley rats were divided into three groups: control group (saline), therapeutic dose group (1 microg/kg/week), and one-log overdose group (10 microg/kg/week). Animals had L4-L5 posterior intertransverse process fusion with limited bone graft and were sacrificed at 2, 4, and 6 weeks. Manual palpation showed no notable differences among groups. Treatment group radiographic scores were equal to or better than control group scores and were higher than the overdose group at 2 and 6 weeks. Qualitatively, limited histologic remodeling and poor osteoclastic and osteoblastic function were noted in the alendronate treated groups. Quantitative histologic analysis showed fewer osteoclasts in the therapeutic and high-dose groups (p < 0.001). The percent osteoblasts per bone surface area was lower in the high-dose group (p < 0.05). The results suggest that the effect of alendronate was dose dependent and animal model dependent and that supranormal doses of alendronate had a deleterious effect on osteoclastic and osteoblastic function in this model.

Alendronate↗
PubMed2003

Summary statement: emerging techniques for treatment of degenerative lumbar disc disease.

Emerging techniques for management of degenerative disc disease include modern fusion interbody cage devices, intradiscal electrothermal therapy, and disc prostheses among others. The management of discogenic low back pain is controversial: its accurate diagnosis is difficult, and treatment is inconsistent. Before wide application, the advantages and disadvantages of each procedure must be considered in lieu of inadequate study design and the lack of sufficient long-term outcome studies.

Electrocoagulation↗
PubMed2003

Bone morphogenetic proteins and spinal surgery.

STUDY DESIGN: A review of the literature concerning the use of recombinant human bone morphogenetic proteins 2 (rhBMP-2) and 7 (rhBMP-7) in spinal fusion. PURPOSE: To summarize the pertinent preclinical experiments that enabled regulated human clinical trials of recombinant bone morphogenetic proteins for spinal fusion and to update clinicians on the results of those trials. BACKGROUND: More than three decades of research involving thousands of scientists and academicians throughout the world have led to the clinical use of recombinant bone morphogenetic proteins for the treatment of spinal disease. METHODS: The published and presented scientific literature and the author's personal experience were examined. RESULTS AND CONCLUSIONS: Recent clinical data support the assertion that recombinant bone morphogenetic proteins can be used as complete bone graft substitutes in spinal fusion surgery. In some circumstances, the efficacy of these factors for inducing successful fusion is superior to that of autogenous bone graft. RhBMP-2 is shown to be efficacious in several fusion applications, including intervertebral and lumbar posterolateral. Similar efficacy for rhBMP-7 has not yet been demonstrated, although relevant clinical studies are currently under way. The availability of these biologic agents will improve our ability to predictably treat spinal disease and may facilitate the further development of less invasive surgical innovations.

Animals↗
PubMed2003

BMPs and gene therapy for spinal fusion: summary statement.

The use of biologic technologies to engender spinal fusion is at various stages of scientific and clinical development. Recombinant human bone morphogenetic protein 2 is now available for clinical use in anterior lumbar intervertebral fusion and has been extensively studied in other spinal fusion applications. Recombinant bone morphogenetic protein 7 is under examination in regulated clinical trials. Gene therapy technologies are in the preclinical stage of development. In time, biologic interventions will continue to capture greater roles in the treatment of spinal disease.

Animals↗
PubMed2003

Threaded cortical bone dowels in lumbosacral arthrodesis: a review.

Lumbar fusion is a common spinal surgery, for which numerous devices have been developed to aid in segment stabilization. A threaded cortical bone dowel is a machined and processed bone allograft which is one such development. Threaded cortical bone dowels are attractive because of their osteoconductive nature and the opportunity to load them with osteogenic morselized bone autograft or osteoinductive growth factors, such as bone morphogenetic proteins. Although threaded cortical bone dowels have been in clinical use for more than 5 years, they have not been the subject of a comprehensive review. The current article covers the history, preparation, uses, safety, and efficacy of threaded cortical bone dowels in lumbosacral interbody fusion.

Bone Transplantation↗
PubMed2003

A cost analysis of bone morphogenetic protein versus autogenous iliac crest bone graft in single-level anterior lumbar fusion.

An economic model was developed to compare costs of stand-alone anterior lumbar interbody fusion with recombinant human bone morphogenetic protein 2 on an absorbable collagen sponge versus autogenous iliac crest bone graft in a tapered cylindrical cage or a threaded cortical bone dowel. The economic model was developed from clinical trial data, peer-reviewed literature, and clinical expert opinion. The upfront price of bone morphogenetic protein (3380 dollars) is likely to be offset to a significant extent by reductions in the use of other medical resources, particularly if costs incurred during the 2 year period following the index hospitalization are taken into account.

Bone Morphogenetic Protein 2↗
PubMed2002

Animal models for preclinical assessment of bone morphogenetic proteins in the spine.

STUDY DESIGN: A review of the rationale behind the use of animal models for the assessment of bone morphogenetic proteins (BMPs) in the spine. OBJECTIVE: To summarize the underlying principles of animal experimentation in the context of bone morphogenetic proteins and the spine. SUMMARY OF BACKGROUND DATA: Animal models aid in the collection of important information regarding the precise mechanobiologic events that occur during spinal fusion healing. Reproducible spinal fusion models have been developed in several animal species, leading to experimentation in a controlled fashion. Reliable assessment of outcome measures for osseous healing, including histology and biomechanical testing, has made preclinical testing of innovative growth factors essential before the advance to clinical trials. METHODS: These materials have initially gone through the "burden of proof" steps: proof of concept studies, feasibility studies, and efficacy studies. RESULTS AND CONCLUSIONS: Bone morphogenetic proteins have undergone extensive scrutiny in the preclinical arena. This article summarizes the evolution of animal experimentation with BMP including the background and future directions.

Animals↗
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

Factors predicting hospital stay, operative time, blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation.

STUDY DESIGN: A retrospective chart review was conducted for 112 patients who underwent revision posterior lumbar spine decompression, fusion, and segmental instrumentation. OBJECTIVE: To ascertain factors predicting hospital stay, operative time, blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation. SUMMARY OF BACKGROUND DATA: Posterior lumbar spine decompression and fusion with segmental instrumentation is a common procedure in the treatment of degenerative lumbar spine disorders. Many patients undergoing this procedure have had previous lumbar spine surgery, yet little is known about the factors predicting hospital stay, operative time, blood loss, and transfusion. METHODS: The charts of 112 patients (53 men and 59 women) with degenerative lumbar spinal stenosis who underwent revision surgery from March 1992 to June 1999 were reviewed. Their average age was 54 years (range, 27-84 years). All the surgeries included decompression and fusion with segmental instrumentation. The patients' demographics, comorbid conditions, factors related to previous lumbar spine surgery, diagnosis, number of levels fused, and preoperative hemoglobin and hematocrit were collected and used as the independent variables. Multiple regression analysis was used to ascertain factors predicting length of hospital stay, operative time, intraoperative blood loss, and transfusion. RESULTS: The mean length of hospital stay was 6 +/- 2.4 days, the operative time 280 +/- 62 minutes, the estimated intraoperative blood loss 1073 +/- 716 mL, and the total volume of blood transfused 1.04 +/- 1.17 U. For 63% of the patients, a blood transfusion was needed. Increasing age was the significant predictor for hospital stay (P < 0.001). The factors predicting operative time were number of levels fused (P < 0.001), diagnosis of degenerative scoliosis (P < 0.05), and excessive body weight (P < 0.01). The factors predicting intraoperative blood loss were number of levels fused (P < 0.01), body weight (P < 0.001), and high preoperative hemoglobin (P < 0.001). Both logistic and linear regression analysis showed that the factors predicting blood transfusion were number of levels fused (P < 0.01), age (P < 0.05), and low preoperative hemoglobin (P < 0.001). Other factors associated with hospital stay and blood transfusion were unemployment associated with three or more comorbid conditions and complications. The women had less intraoperative blood loss (P < 0.01), but received more transfused blood than the men (P < 0.01). CONCLUSIONS: Number of levels fused and age seem to be the most significant factors predicting hospital stay, operative time, intraoperative blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation.

Adult↗