Surgical outcomes of long spinal fusions for scoliosis in adult patients with rheumatoid arthritis.

OBJECT: In this study, the authors compared outcomes and complications in patients with and without rheumatoid arthritis (RA) who underwent surgery for spinal deformity. METHODS: The authors searched the Johns Hopkins University database for patients with RA (Group RA) and without RA (Group NoRA) who underwent long spinal fusion for scoliosis by 3 surgeons at 1 institution from 2000 through 2012. Groups RA and NoRA each had 14 patients who were well matched with regard to sex (13 women/1 man and 12 women/2 men, respectively), age (mean 66.3 years [range 40.5-81.9 years] and 67.6 years [range 51-81 years]), follow-up duration (mean 35.4 months [range 1-87 months] and 44 months [range 24-51 months]), and number of primary (8 and 8) and revision (6 and 6) surgeries. Surgical outcomes, invasiveness scores, and complications were compared between the groups using the nonpaired Student t-test (p < 0.05). RESULTS: For Groups RA and NoRA, there were no significant differences in the average number of levels fused (10.6 [range 9-17] vs 10.3 [range 7-17], respectively; p = 0.4), the average estimated blood loss (2892 ml [range 1300-5000 ml] vs 3100 ml [range 1700-5200 ml]; p = 0.73), or the average invasiveness score (35.5 [range 21-51] vs 34.5 [range 23-58]; p = 0.8). However, in Group RA, the number of major complications was significantly higher (23 vs 11; p < 0.001), the number of secondary procedures was significantly higher (14 vs 6; p < 0.001), and the number of minor complications was significantly lower (4 vs 12; p < 0.001) than those in Group NoRA. CONCLUSIONS: Long spinal fusion in patients with RA is associated with higher rates of major complications and secondary procedures than in patients without RA.

The History of Spinal Deformity.

The description and history of the treatment of spinal disorders have evolved from very early Grecian and Hindu times through to today's complex techniques. An emphasis on renowned figures from throughout the world who have contributed greatly to our understanding and care of spinal deformities is provided. Knowledge of the past provides significant input to our understanding of the current problems and enhances the development of future modalities of care.

Effect of epsilon aminocaproic acid on red-cell transfusion requirements in major spinal surgery.

STUDY DESIGN: : Randomized, placebo-controlled trial. OBJECTIVE: : To evaluate the efficacy of epsilon aminocaproic acid (EACA) to reduce the number of red-cell (RBC) transfusions in adult patients undergoing major spinal surgery. SUMMARY OF BACKGROUND DATA: : Reconstructive spinal surgery is associated with significant blood loss. The number of studies evaluating the efficacy of EACA in adult patients undergoing spinal surgery remains scarce and limited. METHODS: : EACA (100 mg/kg) or placebo was administered to 182 adult patients after the induction of anesthesia followed by an infusion that was continued for 8 hours after surgery. Primary end points included total allogeneic RBC transfusions through postoperative day 8 and postoperative allogeneic plus autologus RBC transfusions through postoperative day 8. RESULTS: : Mean total allogeneic RBC transfusions were not statistically different between the groups (5.9 units EACA vs. 6.9 units placebo; P = 0.17). Mean postoperative RBC transfusions in the EACA group was less (2.0 units vs. 2.8 units placebo; P = 0.03). There was no significantdifference in mean estimated intraoperative estimated-blood loss (2938 cc EACA vs. 3273 cc placebo; P = 0.32). Mean intensive care unit length of stay was decreased (EACA: 1.8 days vs. 2.8 days placebo; P = 0.04). The incidence of thromboembolic complications was similar (2.2% EACA vs. 6.6% placebo; P = 0.15). CONCLUSION: : The difference in total allogeneic RBC transfusions between the groups was not statistically significant. EACA was associated with a 30% (0.8 units) reduction in postoperative RBC transfusions and a 1-day reduction in ICU LOS, without an increased incidence of thromboembolic events. EACA may be considered for patients undergoing major spinal surgery. Larger studies are needed to evaluate the relationship between EACA and total RBC requirements.

Short-term mortality and its association with independent risk factors in adult spinal deformity surgery.

STUDY DESIGN: Retrospective review. OBJECTIVES: To determine postoperative mortality after adult spinal deformity surgery. To determine whether independent risk factors can predict mortality. SUMMARY OF BACKGROUND DATA: Although mortality after adult spinal surgery is reported to range from 0.03% to 3.52%, there is a general paucity of data on mortality and its associated risk factors after adult spinal deformity surgery. METHODS: Three hundred sixty-one adults with spinal deformity underwent 407 corrective procedures. For patients who died within 30 days of the procedure, the following risk factors were examined to determine if each could independently predict mortality: demographic information, American Society of Anesthesiologists' (ASA) classification, operative time, surgical approach, number of fusion levels, primary versus revision surgery, and intraoperative blood loss. RESULTS: Ten of the 407 procedures resulted in death (2.4% mortality): 1 intraoperatively secondary to cardiac ischemia, 3 secondary to sepsis/multiple organ failure, 2 each secondary to pulmonary embolus, uncal herniation/cerebral edema, and shock. The average preoperative ASA levels for patients who died and patients who survived were 3.0 and 2.3, respectively (P < 0.0001). Age, gender, operative time, surgical approach, number of fusion levels, revision status, and estimated blood loss did not have an independently significant correlation to mortality. CONCLUSION: There was a strong association (P < 0.0001) between increasing ASA class and increasing mortality. The other risk factors could not independently predict postoperative mortality within 30 days after adult spinal deformity surgery.

Pulmonary embolism after adult spinal deformity surgery.

STUDY DESIGN: Retrospective review. OBJECTIVE: To determine the incidence and identify the associated risk factors of pulmonary embolism (PE) in patients who receive pharmacologic thromboprophylaxis after adult spinal deformity surgery. SUMMARY OF BACKGROUND DATA: The risk of PE after adult spinal deformity surgery is reported to be as high as 2.2%. However, the incidence and associated risks of PE in the same patient population who receive postoperative pharmacologic thromboprophylaxis is unknown. METHODS: The study included 361 adult patients with spinal deformity who underwent 407 corrective spinal procedures for scoliosis, kyphosis, or kyphoscoliosis. The incidence of PE was determined and compared with a study (historical control) of similar patients undergoing similar surgery but without postoperative pharmacologic thromboprophylaxis. Their demographic information, American Society of Anesthesiologists score, operative time, surgical approach, surgical complexity, and intraoperative blood loss were also analyzed to determine the presence of associated risk factors. RESULTS: Despite universal pharmacologic thromboprophylaxis, 10 pulmonary emboli (2.4%) were diagnosed. Patients undergoing anterior spinal surgery were at a significantly higher risk than those undergoing posterior spinal surgery (P = 0.024). The right-side anterior approach was also associated with a significantly higher incidence of PE compared with the left-sided anterior approach (P = 0.018). Although the rate of PE after posterior spinal surgery did not differ from the historical control, the rate of PE after anterior surgery was reduced by 50% compared with the historical control. Age, gender, estimated blood loss, operative time, revision status, and the number of fusion levels were not significant variables for PE. There were 2 epidural hematomas requiring decompression (0.48%) and 1 wound hematoma (0.24%). CONCLUSION: Although pharmacologic thromboprophylaxis probably does not have a role after posterior spinal surgery, the data in this study suggest that it does lower the incidence of PE after anterior spinal surgery.

Posterior only versus combined anterior and posterior approaches to lumbar scoliosis in adults: a radiographic analysis.

STUDY DESIGN: Retrospective study. OBJECTIVE: To compare the radiographic lumbar curve correction between a posterior only and combined anterior-posterior approach in patients with adult spinal deformity. SUMMARY OF BACKGROUND DATA: In adolescent idiopathic scoliosis correction, posterior only has been compared with the combined anterior-posterior approach; however, there have been no corollary studies in adult scoliosis. Traditionally, rigid lumbar curves have been treated with a combined anterior and posterior approach; however, the absolute indications for this approach are unclear. MATERIALS AND METHODS: A total of 180 patients with degenerative or adult idiopathic spinal deformity and curves measuring between 40 degrees and 70 degrees who underwent reconstructive spinal fusion. The minimum follow-up period was 28 months and average follow-up was 53 months. Of the 155 patients who underwent surgery, 80 underwent posterior only (35 with idiopathic and 45 with degenerative scoliosis) while 75 patients (30 with idiopathic and 35 with degenerative scoliosis) underwent combined anterior-posterior surgery. The groups were compared by age at operation, preoperative deformity, levels operated and postoperative correction and balance. RESULTS: There were no significant differences in sagittal and coronal plane curve and balance correction between the posterior only and the combined anterior-posterior groups. When the patients were subdivided into degenerative adult scoliosis and idiopathic adult scoliosis, there were again no significant differences in the sagittal and coronal curves or balance between the posterior only and combined anterior and posterior approaches. While the posterior only group and the same-day anterior and posterior surgery group had a similar major complication rate of 24% and 23%, respectively, patients who underwent staged anterior and posterior surgery had a major complication rate of 45%. CONCLUSION: When combined with extensive posterior releases, posterior only approach is just as effective as combined anterior and posterior surgery for adult lumbar scoliosis measuring between 40 degrees and 70 degrees .

Physician-owned companies.

STUDY DESIGN: The author relates his experience in the development of a spinal implant development company (K2M) that is significantly advised by physicians. OBJECTIVES: To provide information about the development of a spinal implant company (K2M) advised by a group of professional spinal surgeons. To relate the federal laws (STARK and anti-kickback) as they pertain to surgeon-influenced companies. To discuss the role of a scientific advisory board. METHODS: A self-developed company was developed together with significant, but minority physician financial input and majority scientific advice. RESULTS: A privately owned spinal implant development corporation (K2M) was developed 3 years ago. Physician financial participation was less than 20% (Stark laws state no more than 40%). Users of product are greater than 60% non-investor physicians. The development of a large scientific advisory board has been very influential in product development. CONCLUSIONS: A privately owned spinal implant company (K2M) has been developed strictly within Federal laws. Its board of scientific advisors that receives recompense commissurate only with effort significantly impacts the company policy.

Small intestinal submucosa as a potential bioscaffold for intervertebral disc regeneration.

STUDY DESIGN: To evaluate the capacity of porcine small intestine submucosa to support the in vitro proliferation of human disc cells and the synthesis of extracellular matrix that could restore the biochemical properties of the disc. OBJECTIVE: To evaluate if porcine small intestine submucosa is a potential bioactive scaffold for rescuing degenerative disc cells. SUMMARY OF BACKGROUND DATA: Discogenic back pain is associated with alterations of the disc and abnormal turnover of the disc extracellular matrix. We hypothesize that a biodegradable and biocompatible acellular scaffold such as small intestine submucosa, which contains entrapped growth factors, may stimulate disc cells to synthesize extracellular matrix, thereby arresting the degeneration, or even promoting the regeneration, of the disc. METHODS: Human degenerative anulus and nucleus cells were seeded onto small intestine submucosa scaffolds, and evaluated over a 3-month period for cell growth (proliferation assay, deoxyribonucleic acid content) and matrix composition (glycosaminoglycan and collagen contents). RESULTS: As hematoxylin and eosin staining revealed, more than 70% of seeded cells attached to the small intestine submucosa surface and invaded throughout the scaffold. The macroscopic appearance of cell-seeded scaffolds was dramatically modified over time. Cell metabolic activity was confirmed for up to 3 months. Seeded scaffolds showed a higher glycosaminoglycan content as compared to control scaffolds. Toluidine blue staining detected large areas of proteoglycans. Positive gene expression for collagens I, II, and X, aggrecan, and Sox-9 confirmed deposition of new extracellular matrix components. CONCLUSIONS: This pilot study shows that small intestine submucosa is a promising bioactive material that could potentially serve as a temporary scaffold for intervertebral disc regeneration.

In vivo evaluation of plasmid DNA encoding OP-1 protein for spine fusion.

STUDY DESIGN: A posterolateral lumbar interbody arthrodesis animal model was selected to evaluate the percutaneous delivery of OP-1 plasmid DNA. OBJECTIVE.: To evaluate the feasibility of achieving ectopic bone formation using nonviral gene delivery with a minimally invasive technique, by coinjecting plasmid DNA encoding OP-1 with collagen into the paraspinal muscle. SUMMARY OF BACKGROUND DATA: Osteoinductive proteins show great promise for achieving spine fusion but suffer from poor bioavailability. Viral gene transfer can produce therapeutic and sustained levels of osteoinductive proteins to achieve osteogenesis in a variety of animal models. Toxicity and immunogenicity concerns, however, limit the appeal of viral gene therapy for spine fusion. METHODS: Single-level posterior lumbar arthrodesis was attempted at L5-L6 in 64 adult Sprague-Dawley rats bilaterally. OP-1 plasmid DNA was injected with and without collagen carrier above the L5 transverse process either percutaneously or after open surgery. Bone formation was evaluated at 2 and 4 weeks by manual palpation, posterolateral radiographs, and nondecalcified histology. Control animals received the rhOP-1 protein. RESULTS: Bone formation was detected histologically after the percutaneous and open surgical delivery of 25 microg or 500 microg, respectively, of OP-1 plasmid DNA (pVR1055-OP1) and collagen (bone formation = 75% and 50%), but was weaker than that observed after injection of 30 microg of rhOP-1 protein and collagen (bone formation = 100%). Single-level spine fusion was only achieved in groups receiving percutaneous OP-1 protein and collagen (30 microg protein, fusion rate = 100%) or high concentrations of OP-1 protein alone (40 microg protein, 100%), as confirmed through manual palpation, histology, and radiography. CONCLUSIONS.: These data confirm that OP-1 plasmid DNA can successfully generate bone formation in vivo.

Interaction of human mesenchymal stem cells with disc cells: changes in extracellular matrix biosynthesis.

STUDY DESIGN: To evaluate the in vitro interactions between human mesenchymal stem cells (MSCs) and degenerative disc cells. OBJECTIVES: To demonstrate the potential of MSCs in regulating the extracellular matrix synthesis of degenerative disc cells. SUMMARY OF BACKGROUND DATA: Culture of degenerative disc cells followed by their reinsertion into a disc can retard the degeneration process in an animal model. However, harvesting cells without accelerating degeneration is problematic. Autologous MSCs can be safely harvested from the bone marrow and transplanted into degenerative discs. METHODS: Human degenerative nucleus pulposus (NP), anulus fibrosus (AF) cells, and MSCs were cultured as pellets, and coculture pellets were formed by addition of MSCs to disc cells (50:50 ratio). Glycosaminoglycan (GAG) and DNA content were measured. Proteoglycan synthesis was analyzed by RT-PCR and western blot. Type II collagen expression was assessed by immunohistochemistry. RESULTS: Coculture pellets formed by the addition of MSCs to AF cells were superior in size to all other pellets. AF/MSC pellets showed higher experimental GAG content than the predicted values represented by the sum of individual control pellets, with 10.2 versus 5.6 microg/pellet at week 3, respectively. The effect was not observed in the NP/MSC coculture, or when chondrogenic medium was used. Close contact between cells was necessary to obtain this enhancement of GAG content. Proteoglycan and collagen expression in both individual and coculture pellets was confirmed by PCR analysis and western blot. CONCLUSION: Addition of MSCs to AF cells resulted in an up-regulation of the proteoglycans synthesis. This study provides the rationale for further investigation of the potential of MSC therapy in treating intervertebral disc degeneration.

Spinal fusion after revision surgery for pseudarthrosis in adult scoliosis.

STUDY DESIGN: A retrospective study. OBJECTIVE.: To decipher the incidence, characteristics, functional outcomes, and complications of spinal fusion after revision surgery for recurrent pseudarthrosis in adult patients with scoliosis. SUMMARY OF BACKGROUND DATA: While the rate of spinal fusion has been examined in the past, there have been no studies that have examined the incidence, characteristics, functional outcomes, and complications of spinal fusion after pseudarthrosis repair in adult patients with scoliosis. MATERIALS AND METHODS: A total of 132 patients with failed spinal fusion surgery for adult scoliosis and painful pseudarthroses were studied. Each patient had an average of 3.7 spinal surgeries before undergoing revision at our institution. In addition to clinical assessment and imaging studies, pseudarthrosis was confirmed intraoperatively in all patients. All patients underwent reinstrumentation and fusion along with adjunctive procedures as needed. Spinal fusion was assessed clinically and radiographically after surgery for a minimum of 40 months. Subjective functional outcomes and complications associated with the procedures were also studied. RESULTS: The overall incidence of spinal fusion after revision surgery for pseudarthrosis in adult scoliosis was 90%. There was a propensity for pseudarthrosis to recur at the thoracolumbar and lumbosacral junctions. Increasing thoracolumbar kyphosis and loss of sagittal balance were significant risk factors for recurrent pseudarthrosis after revision surgery (mean thoracolumbar kyphosis of 23 degrees and mean sagittal balance of 7.9 cm anteriorly associated with persistent pseudarthrosis). Additionally, patients with multiple preoperative sites of pseudarthroses were at a higher risk for continued pseudarthrosis after surgery. Cigarette smoking, age, and surgical approach did not have any significant correlation with pseudarthrosis. Seventy-two percent of patients were satisfied with the outcome and 80% would have chosen to undergo surgery again if necessary. Thirty-three percent of patients who underwent surgery had some complication related to the surgery. CONCLUSION: Revision surgery for pseudarthrosis repair in adult scoliosis is most successful at attaining fusion when thoracolumbar and overall sagittal alignment are restored as much as possible.

Nonsurgical resource utilization in adult spinal deformity.

STUDY DESIGN: The enrollment data were retrospectively reviewed for 1,061 patients entered into a prospective multicenter study of adult spinal deformity between January 2002 and June 2004. OBJECTIVE: The purpose of this study is to quantify and analyze the use of nonsurgical resources in patients with adult spinal deformity. SUMMARY OF BACKGROUND DATA: Limited data exist regarding the utilization of nonsurgical treatment methods for adult spinal deformity. METHODS: Demographic data, surgical history, symptom assessment, and nonsurgical treatment regimen were reviewed. Health status measures were the SF-12, SRS-29, and ODI. Nonsurgical patients were divided into low- and high-symptom subgroups based on age adjusted ODI score. Resource utilization was analyzed based on both patient and physician questionnaire responses. RESULTS: High- and low-symptom nonsurgical subgroups differed significantly on all reported health status measures (P < 0.0001). High-symptom patients used greater resources in terms of narcotics, epidural blocks, and physical agent methods (P < 0.001), analgesics (P < 0.01), pain management referral and bed rest (P < 0.02), strength training, nerve root blocks, and stabilization exercises (P < 0.05). CONCLUSIONS: The results of this study demonstrate that, within the population of adult deformity patients, distinct high- and low-symptom groups exist and can be clearly identified. While high-symptom patients used significantly greater resources, most low-symptom patients used nonsurgical resources as well.

Temperature-responsive hydroxybutyl chitosan for the culture of mesenchymal stem cells and intervertebral disk cells.

Temperature-responsive polymers are attractive candidates for applications related to injectable delivery of biologically active therapeutics, such as stem cells. In this study, we evaluate the potential of thermosensitive hydroxybutyl chitosan (HBC) as a biomaterial for the culture of human mesenchymal stem cells (hMSC) and cells derived from the intervertebral disk, with the eventual goal of using the HBC polymer as an injectable matrix/cell therapeutic. Conjugation of hydroxybutyl groups to chitosan renders the polymer water soluble and thermally responsive. Below its lower critical solution temperature, a solution of HBC can be maintained indefinitely in its solvated state. Upon exposure to a 37 degrees C environment, within 60 s, a 3.8 wt% HBC solution rapidly forms a gel that can be maneuvered with forceps. Upon cooling, the gel once again is able to revert to its solvated state. The gel exhibits a dramatic increase in both G' and G'' with increasing temperature, signifying a temperature-dependent enhancement of gel mechanical properties. Although a solid structure upon gelation, due to its physical nature of polymer interaction and gel formation, the gel exhibits a fluid-like viscoelastic behavior when exposed to shear stresses of up to 10% strain, with both G' and G'' approaching zero with increasing shear stress. Formulations of HBC gels presented in this study have gelation temperatures ranging from 13.0 to 34.6 degrees C and water contents of 67-95%. Minimal cytotoxicity in MSC and disk cell cultures was observed with these polymers up to a concentration of 5 wt%. Detection of metabolic activity, genetic analysis of synthesized mRNA, and histological staining of MSC and disk cell cultures in these gels collectively indicate cell proliferation without a loss in metabolic activity and extracellular matrix production. This study suggests the potential of HBC gel as an injectable carrier for future applications of delivering therapeutics to encourage a biologically relevant reconstruction of the degenerated disk.

Functional and radiographic outcome of sacroiliac arthrodesis for the disorders of the sacroiliac joint.

BACKGROUND CONTEXT: The sacroiliac joint is known to be a possible cause of chronic low back pain, but the diagnosis and treatment of disorders of the sacroiliac joint have been difficult and controversial. PURPOSE: To describe the outcome of sacroiliac joint arthrodesis for sacroiliac joint disorders, with the hypothesis that sacroiliac arthrodesis leads to improved postoperative function. STUDY DESIGN/SETTING: Consecutive case series performed in an academic medical institution. PATIENT SAMPLE: The patient population consisted of 20 patients undergoing sacroiliac joint arthrodesis between December 1994 and December 2001. Patients undergoing concomitant procedures at the time of sacroiliac joint arthrodesis were excluded. The 3 men and 17 women in the study group had an average age of 45.1 years (range 21.8-66.4 years), a mean duration of symptoms of 2.6 years (range 0.5-8.0 years), and a mean follow-up period of 5.8 years (range 2.0-9.0 years). OUTCOME MEASURES: Outcome measures included general health and function, clinical evaluation, and radiographic assessment. METHODS: For all 20 patients, nonoperative treatment had failed, and for all, the diagnosis was confirmed by pain relief with intraarticular sacroiliac joint injections under fluoroscopic guidance. Sacroiliac joint arthrodesis (via a modified Smith-Petersen technique) was recommended only when a positive response to the injection was noted, and patients had recurrence of symptoms after the initial positive response. Preoperative and postoperative general health and function were assessed via the 36-item Short-Form (SF-36) Health Survey and American Academy of Orthopaedic Surgeons (AAOS) Modems Instrument, which were collected prospectively. Medical records and plain radiographs were reviewed retrospectively to determine the clinical and radiographic outcome. RESULTS: Multiple etiologies of sacroiliac symptoms were observed: sacroiliac joint dysfunction (13 patients), osteoarthritis (5 patients), and spondyloarthropathy and sacroiliac joint instability (1 each). Seventeen patients (85%) had solid fusion. Fifteen patients (75%) completed preoperative and postoperative SF-36 forms. Significant (p< or =.05) improvement occurred in the following categories: physical functioning, role physical, bodily pain, vitality, social functioning, role emotional, and neurogenic and pain indices. Improvement (not statistically significant) was also noted in general and mental health. CONCLUSIONS: For carefully selected patients, sacroiliac arthrodesis appears to be a safe, well-tolerated, and successful procedure, leading to significant improvement in functional outcome and a high fusion rate. To the authors' knowledge, the current report is the largest series to document the functional and radiographic outcome of sacroiliac joint arthrodesis.

Lumbar nerve root palsy after adult spinal deformity surgery.

STUDY DESIGN: A retrospective study was conducted to investigate the incidence and prognosis of postoperative lumbar nerve root palsy after surgical treatment for adult spinal deformity. OBJECTIVE: To decipher the incidence of postoperative lumbar nerve root palsy and recovery in 361 adult spinal deformity patients who underwent 407 spinal fusion surgeries. SUMMARY OF BACKGROUND DATA: Although lumbar nerve root palsy is a known complication of spinal surgery, there are no large studies that have examined its incidence or prognosis. METHODS: Three hundred and sixty-one consecutive patients who underwent 407 procedures for adult deformity spinal surgery were reviewed. Patients in this study did not have spinal cord injury or nerve root compression on the postoperative imaging study (obtained for change in neurologic examination). The incidence of nerve root palsy was based on postoperative muscle strength, which was followed for a minimum of 3 and an average of 7 years. RESULTS: The overall incidence of lumbar nerve root palsy was 2.9% with a 1.4% incidence in primary and 3.8% incidence in revision surgery. The incidence was 0.9, 1.5, and 7.4% for fusion of <5 levels, 5 to 10 levels, and >10 levels, respectively. The incidence of nerve root palsy for posterior only, same day anterior-posterior, and staged posterior was 1.3, 3, and 7.2%, respectively. While L5 was the most commonly injured nerve root, all other lumbar nerve roots were also involved. There were no S1 injuries. Although there was some recovery in most injuries, Grade IV injuries had the best recovery at 1-year follow-up. CONCLUSION: Patients with increasingly complex spinal deformities are at a higher risk for postoperative lumbar nerve root palsy. These injuries can be treated nonoperatively when there is no identifiable cause on postoperative imaging studies.

Central cord syndrome after total hip arthroplasty: a patient report.

STUDY DESIGN: Case report. OBJECTIVE: To present a patient with central cord syndrome injury after total hip arthroplasty performed under general endotracheal anesthesia. SUMMARY OF BACKGROUND DATA: Central cord syndrome, a common injury usually sustained as a result of an extension injury to the cervical spine, often occurs in geriatric patients with underlying spondylotic changes. The injury results in weakness and sensory changes, which are more pronounced in the upper than in the lower extremities. Patients with this syndrome experience variable return of function, but some degree of residual deficit and spasticity is likely. METHODS: The medical record, including the intraoperative anesthesia records, operative notes, progress notes, discharge summary, clinic notes, and radiology studies and reports, was reviewed. RESULTS: The patient developed signs of central cord syndrome after total hip arthroplasty. Despite nonoperative intervention, including physiotherapy, the patient's upper and lower extremity weakness continued. Magnetic resonance imaging revealed evidence of cervical cord compression, and the patient underwent a cervical laminectomy, which produced mild improvement in his symptoms. CONCLUSIONS: To avoid life-altering complications, it is important to evaluate the cervical spine (especially in the elderly), avoid neck extension during intubation, and use careful airway management in patients with suspected stenosis/spondylosis.

Evaluation of the biological response of wear debris.

STUDY DESIGN: An animal study was conducted to evaluate the biological response to titanium particles from an artificial intervertebral disc in terms of serology and histologic changes. OBJECTIVES: To determine the biological response to wear debris in the retroperitoneal and epidural space. SUMMARY OF BACKGROUND DATA: Few wear studies exist about mechanical artificial discs. METHODS: Twenty-three New Zealand white rabbits were used for two approaches of the lumbar spine. In a retroperitoneal group (10 rabbits), lateral flank approach at the L2-L3 area was used. In an epidural group (13 rabbits), a dorsal laminotomy of L2 was performed. The wear debris was obtained from mechanical test cycling of the implantable intervertebral disc. At 4 and 12 weeks postoperatively, five or six animals from each group were killed. The tissues, including deposition site, regional lymph nodes and major organs, were evaluated with hematoxylin and eosin staining. RESULTS: At death all rabbits were found to be healthy. Blood results from the predeath samples were found to be consistent with the preoperative blood work values. Scar tissue was minimal with good healing. All organs were found to be normal in appearance. On histopathology sections, adverse reactions such as fibrosis, granuloma formation or necrosis were not found in any tissues. Free particles were found sparingly in all tissue sections with minimal cellular response. No remarkable difference was found according to groups or time intervals. Smaller particles were found to be engulfed in macrophages without adverse biological consequences. CONCLUSION: Titanium particles traveled from the sites of deposition but elicited no to minimal biological response.

Complications and surgical revision for failed disc arthroplasty.

This review will outline the indications and options for revision of failed disc arthroplasty. Such indications may include implant loosening, malposition, displacement, early wear, and infection. Each indication will likely require different preoperative planning, testing, and strategies.