Biomedical subjects

Andrew A Sama

Publications and source records attributed to Andrew A Sama.

7 recordsLinked to original sources

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

Postoperative infections in interbody fusion for degenerative spinal disease.

UNLABELLED: Scant literature exists on the treatment of infection after interbody fusion. Some authors advocate removal of the interbody grafts. Salvage of the grafts was possible in 92.3% (12 of 13) of the infections in a series of 326 consecutive patients with degenerative spinal diseases treated by three surgeons. Posterior interbody fusion and posterolateral instrumented fusion was performed in 267 patients and anterior interbody fusion was done in 59 patients. Eight infections in the first group (3%) and six in the second group (10.1%) were identified. Mean followup was 18 months (range, 12-38 months). All infections were early, presenting at a mean of 18 days (range, 11-28 months). All but one infection were in the posterior wound and deep. A high number of risk factors were present in these patients. Initial treatment included wound debridement and broad spectrum antibiotics, until culture results indicated the final antibiotic regimen. Infection recurred as osteomyelitis in one patient with multiple previous surgeries and anterior/posterior fusion. This was treated with removal of the posterior instrumentation and the interbody graft and extensive anterior/posterior reconstruction. Clinical outcomes were good in 10 patients, fair in two and poor in one using the Stauffer-Coventry scale. One pseudarthrosis was identified in a patient with anterior interbody fusion at final followup. Salvage of the interbody graft and retaining the instrumentation was safe in most cases in the presented series and did not adversely affect outcome. LEVEL OF EVIDENCE: Therapeutic study, level IV (case series). Please see the Guidelines for Authors for a complete description of levels of evidence.

Adult↗

PubMed2006

Oncologic and functional outcome following sacrectomy for sacral chordoma.

BACKGROUND: Sacral chordoma is a rare, low to intermediate-grade tumor that poses substantial challenges in terms of timely diagnosis and adequate treatment. Few studies have examined the oncologic and functional outcomes of patients treated for sacral chordoma. METHODS: The clinical records of sixteen patients who had undergone sacrectomy for chordoma between 1985 and 2001 were evaluated retrospectively. All patients underwent resection by means of a sequential combined anterior and posterior approach. Patients were followed clinically at six-month intervals following recovery from the index surgical procedure. The disease onset, treatment, hospital stay, recurrence rates, survival, adjuvant therapy, functional outcome measures, and complications were evaluated. RESULTS: The average age at the time of diagnosis was sixty-one years. The mean tumor size was 15.2 cm in diameter, and all patients had a resection involving S1 or S2. The mean duration of follow-up was sixty-six months, and the tumor recurred in twelve of the sixteen patients. The mean time to metastasis was fifty months. Four patients were clinically disease-free at a mean follow-up of 94.5 months, while five patients died as a result of progressive local or metastatic disease at a mean follow-up of 31.4 months. Only one patient had normal bowel and bladder control postoperatively, and only three were able to walk without assistive devices. Eight patients had wound complications, and one patient had a deep-vein thrombosis. With the numbers available, neither negative margins at the time of initial tumor resection nor adjuvant radiation therapy had a significant impact on survival or local recurrence. More cephalad levels of resection were associated with significantly worse bowel (p = 0.01) and bladder (p = 0.01) control. Complications were frequent and were more common with a larger tumor size at the time of presentation (p = 0.034). CONCLUSIONS: The treatment of sacral chordoma is an arduous clinical undertaking that requires a multidisciplinary approach and attention to detail from the outset. Despite aggressive well-planned surgical management and adherence to strict surveillance protocols, frequent recurrence and the late onset of metastatic disease are to be expected in a substantial proportion of patients, especially those with a very large chordoma or one at a more cephalad level. Adequate surgical treatment results in substantial functional impairment and numerous complications; however, it does offer the possibility of long-term disease-free survival. We advocate an attempt at complete resection, when there is still a possibility of cure, and aggressive treatment of local recurrences. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Adolescent↗

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

The treatment of large (>70 degrees) thoracic idiopathic scoliosis curves with posterior instrumentation and arthrodesis: when is anterior release indicated?

STUDY DESIGN: Retrospective clinical study from 2 centers. OBJECTIVE: To analyze the efficacy of posterior instrumentation and arthrodesis for thoracic idiopathic scoliosis curves more than 70 degrees. SUMMARY OF BACKGROUND INFORMATION: The increasing use of thoracoscopic techniques in deformity surgery has led several investigators to advocate anterior release followed by posterior instrumentation when treating "stiff" thoracic curves 60 degrees-70 degrees. To our knowledge, no study has been published to define indications for anterior surgery in thoracic idiopathic scoliosis. METHODS: This is a retrospective review of patients 20 years and younger, with idiopathic scoliosis and thoracic curves more than 70 degrees treated with isolated posterior instrumentation and arthrodesis at 2 institutions from 1989 to 1999. A total of 50 patients were identified, and 46 were available for minimum 2-year radiographic follow-up. Of the 50 patients, 44 had bend films taken before surgery. All patients were treated with third-generation segmental spinal instrumentation using a varied combination of hooks, wires, and screws. RESULTS: Average patient age at surgery was 14.4 years (range 10-20), and average radiographic follow-up was 4.4 years (range 2-11.5). Average preoperative thoracic curve was 75 degrees (range 70 degrees-88 degrees), and average bend was 47 degrees (range 28 degrees-60 degrees), a flexibility of 37%. Average postoperative curve was 25 degrees (range 10 degrees-46 degrees), and it was 27 degrees (range 11 degrees-46 degrees) at latest follow-up, a correction of 64%. The average length of surgery was 6.15 hours, mean hospital stay was 8 days, and average blood loss was 1100 cc. The Scoliosis Research Society 22 or 24 was available at a minimum of 2 years in 46 of 50 patients. Mean domain scores were: pain 4.4, self-image 4.3, function 4.3, mental health 4.3, satisfaction 4.7, and total 4.4. Complications included 1 pseudarthrosis, 1 implant removal for prominence, and 1 implant removal for late operative site pain. CONCLUSION: Using posterior surgery only, we have been able to at least equal the results reported in the literature by investigators using combined approaches. Isolated posterior instrumentation and arthrodesis achieve satisfactory cosmetic, radiographic, and patient-based outcomes in adolescents with idiopathic scoliosis with thoracic curves 70 degrees-90 degrees, without the added expense and morbidity of anterior release.

Adolescent↗

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↗

PubMed2002

Computerized frameless stereotactic image guidance in spinal surgery.

Clinical applications of computerized frameless stereotactic image-guided spinal surgery continue to evolve. This article discusses several limiting factors regarding the use of this technology. It discusses the benefits of stereotaxy, which are better realized when there is a distortion of 'normal' anatomy because of previous surgery or severe deformity. The three-dimensional model helps the surgeon navigate the rotated and translated vertebrae. The technology can also be helpful when performing a posterior lumbar interbody fusion, to determine the orientation and depth of placement of the allograft or the cage.

Humans↗