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Ankylosing spondylitis is an inflammatory disease of unknown etiology that affects an estimated 350,000 persons in the United States and 600,000 in Europe, primarily Caucasian males in the second through fourth decades of life. Worldwide, the prevalence is 0.9%. Genetic linkage to HLA-B27 has been established. Ankylosing spondylitis primarily affects the axial skeleton and is characterized by inflammation and fusion of the sacroiliac joints, spine, and hips. The resultant deformity leads to severe functional impairment in approximately 30% of patients. Orthopaedic management primarily involves correction of hip deformity through total hip arthroplasty and, less frequently, correction of spinal deformity with spine osteotomy. Closing wedge osteotomies have the lowest incidence of complications. Whether patients with ankylosing spondylitis are at increased risk for heterotopic ossification remains controversial, but comparison with age- and sex-matched counterparts suggests no dramatically higher risk. Because of the high rate of missed fractures and complications after minor trauma in patients with ankylosing spondylitis, plain radiographs are usually not sufficient for evaluation. Thorough patient assessment should include a comprehensive history, physical examination, and laboratory studies

BACKGROUND CONTEXT: Somatosensory evoked potentials (SSEP) are commonly used to monitor the spinal cord and nerve roots during operative procedures that put those structures at risk. The utility of SSEPs to evaluate cauda equina and nerve root function during posterior spinal arthrodesis with pedicular fixation for degenerative lumbar disease has been reported anecdotally and remains controversial. PURPOSE: An institution-wide review of the ability of SSEP readings to monitor nerve function during posterior lumbar spinal arthrodeses with transpedicular fixation for degenerative lumbar spinal disorders was undertaken. STUDY DESIGN/SETTING: A retrospective review was undertaken. Patient history, preoperative physical examination, intraoperative anesthesia, SSEP records and the postoperative course were reviewed. METHODS: A total of 186 consecutive arthrodeses as described above were reviewed. Patients who had anterior procedures, spondyloreduction or scoliosis correction were excluded from the study. There were 76 male and 110 female patients. Five fellowship-trained spine surgeons placed a total of 888 pedicle screws. Sixty-five percent of the patients had a principal preoperative diagnosis of spinal stenosis with degenerative spondylolisthesis. Other common diagnoses were isthmic spondylolisthesis and degenerative scoliosis. Ninety-three percent of the cases involved decompressive laminectomy. Eight percent had posterior interbody fusions. All pedicle screws were placed without the assistance of fluoroscopy or stereotactic computer-assisted guidance. Screw position was evaluated intraoperatively with standard posteroanterior and lateral radiographs.Anesthetic agents compatible with SSEP monitoring were used in all patients. SSEP baseline readings were obtained in all patients in the operating room soon after induction of general anesthesia. An acute and sustained loss of 50% of the SSEP amplitude and/or increase by 10% of latency from baseline was considered to be pathologic. RESULTS: None of the 186 patients had significant SSEP changes. There were, however, 5 patients with postoperative radiculopathies distinct from their preoperative presentations. Early postoperative plain radiographs and computed assisted tomography (CAT) scans revealed malpositioned pedicle screws. Consequently, eight pedicle screws were either revised or removed. All patients had partial or full recovery of their new deficits after revision surgery. CONCLUSION: We conclude that the use of SSEPs in evaluating pedicle screw placement during lumbar arthrodesis is limited. In this setting, if monitoring is required, alternative methods with greater sensitivity and efficacy should be explored

The existence of diabetes mellitus has been postulated to have a deleterious effect on the outcome following lumbar spine surgery. We retrospectively examined the records and radiographs of 32 diabetic patients (mean age, 60 years) who underwent posterior lumbar fusions using transpedicular instrumentation and iliac crest autograft. Ten patients were insulin-dependent and 22 required oral hypoglycemic agents for at least 1 year prior to surgery. The minimum follow-up time was 2 years after surgery (mean, 2.5 years). Surgical indications included herniated lumbar disk, lumbar spinal stenosis, thoracolumbar trauma, and lumbar pseudarthrosis. Clinical results were evaluated by chart review and/or interview by using Odom's criteria. At follow-up, 75% of patients were graded as excellent or good, and 25% as fair or poor. Twenty-five of 32 patients (78%) had improvement of back pain. Twenty of 27 (74%) patients had improvement of leg pain. Eight of 15 (53%) patients had improvement in motor strength, and 6 of 11 (54%) had improvement in light-touch sensation. Insulin dependence and the presence of polyneuropathy were associated with a poorer outcome. The average time to radiographic fusion was 5 months. Twenty-nine of 32 patients (91%) developed solid fusion by strict radiographic criteria. The three patients with a pseudarthrosis had persistent back pain and a poor result. Ten of 32 (31%) of the patients experienced perioperative complications, including prolonged wound drainage (n = 5), deep wound infection (n = 1), superficial wound infection (n = 1), atrial fibrillation (n = 1), ruptured cerebral aneurysm (n = 1), and ulnar nerve neuropathy (n = 1). We conclude that posterolateral lumbar spinal fusion with internal fixation in diabetic patients yields clinical results comparable to those of nondiabetic patients, with similar risks of perioperative complications

An inevitable side effect of iliac crest bone graft harvesting is postoperative pain at the donor site. Bupivacaine hydrochloride is a long-acting local anesthetic that is clinically effective for approximately 8 hours. The present study was undertaken to assess postoperative pain relief with locally injected bupivacaine at the iliac crest bone graft harvest site. Pain relief with locally injected bupivacaine or saline at the iliac bone harvest site using an indwelling catheter was studied in 13 patients in a prospective, double-blind, crossover study. Twelve patients had cervical diskectomy and arthrodesis with autograft and one patient had a triple arthrodesis of the foot. There were no statistically significant differences between patients given bupivacaine and patients given saline with respect to pain relief ratings and hip-pain ratings at rest and motion during the first 24-hour postoperative period and the second 24-hour postoperative period (Mann-Whitney test). The single diabetic patient who had a triple arthrodesis developed a wound infection at the catheter placement site. The number of patients was too small to draw conclusions about the differences in pain-medication requirements between patients undergoing single versus multiple diskectomies and fusions. In view of the lack of improvement in pain relief and the risk of infection, local administration of bupivacaine at the iliac bone harvest site is not recommended in its present form for postoperative analgesia

BACKGROUND: Approximately 0.9 percent of the white adult population of the United States and 1.1 percent of the adult population in Europe are affected by seropositive rheumatoid arthritis. As many as 10 percent of those patients may need an operation for atlantoaxial subluxation. Severe instability, especially when associated with vertical subluxation of the odontoid process, can result in progressive cervical myelopathy. Typically, occipitocervical fixation has been performed for these patients with use of autograft bone to achieve long-term stability through a solid fusion. Harvesting the bone graft increases the operative risk to the patient and may result in increased morbidity. In our experience, patients who have had no clear radiographic evidence of fusion following use of occipitocervical instrumentation seemed to have done as well as those who have had obvious fusion. One assumption is that the clinical improvement might be attributable simply to stabilization of the joint rather than to osseous fusion. A longitudinal study was performed on patients with rheumatoid arthritis who required an operation because of craniocervical or upper cervical instability. METHODS: The results of clinical, radiographic, functional, and self-evaluations were studied to determine the efficacy of treatment and to compare the outcomes of bone-grafting with those of procedures done without bone-grafting in a group of 150 patients who underwent posterior occipitocervical stabilization with use of a contoured metal implant (a Ransford loop) that was affixed by sublaminar wires. Internal fixation was performed in 120 patients without bone-grafting and in thirty patients with use of autogenous bone-grafting. Preoperatively, 23 percent (thirty-five) of the 150 patients had mild neurological involvement (class II, according to the system of Ranawat et al.), 45 percent (sixty-eight) had objective findings of weakness and long-tract signs but were able to walk (class III-A), and 29 percent (forty-three) were quadriparetic and unable to walk (class III-B). The age of the patients at the time of the operation ranged from twelve to eighty-three years (mean, sixty-two years). RESULTS: There were significant improvements in postoperative Ranawat classes at all time-periods (range, p < 0.00005 to p = 0.0066) and in patient ratings of neck pain (range, p < 0.00005 to p = 0.0044) compared with preoperative scores. With the numbers available, there were no significant differences between the patients managed with a graft and those managed without grafting with respect to survival after the operation, Ranawat class, head or neck-pain rating, presence of subaxial abnormalities, radiographic craniovertebral motion, or vertical subluxation. Overall mortality at one month was 10 percent (fifteen of 150), although this value varied directly with the degree of preoperative disability. A second cervical spine operation was required in 11 percent (sixteen) of the 150 patients. CONCLUSIONS: While patients who have rheumatoid disease with anterior atlantoaxial subluxation should be treated with posterior atlantoaxial arthrodesis with use of bone-grafting and internal fixation, we believe that those who present with vertical instability and multi-level involvement can be treated with posterior occipitocervical stabilization with use of a contoured occipitocervical loop and sublaminar wire fixation without bone-grafting. Furthermore, we believe that the use of preoperative traction, bone cement, or a postoperative halo vest is unnecessary. Avoiding the harvesting of autogenous bone for grafting reduced the morbidity of this operation without compromising the outcome in these already sick patients

The functional results of surgery in patients with myelopathic nonambulatory rheumatoid arthritis (Ranawat Class IIIb) are often disappointing, with high rates of postoperative morbidity and mortality. The authors therefore undertook a detailed investigation of a cohort of 55 Ranawat Class IIIb patients (11 men and 44 women) with a mean age of 64.7 years who were recruited prospectively over a 10-year period (1983-1993), to determine what factors may accurately predict a good surgical outcome. Only 14 patients (25.5%) were judged to have had a favorable outcome as determined by an improvement to Ranawat Class I or II or an improvement of at least 0.5 points in the Stanford Health Assessment Questionnaire disability index. The early postoperative mortality rate was high (12.7%) in this group and almost one-quarter of the patients were dead within 6 months. These poor results mirror those already published in the existing literature. Univariate analysis revealed that age (p = 0.02), degree of vertical translocation (p = 0.05), and, more importantly, spinal cord area (p = 0.006) were significant predictors of outcome. Multiple logistic regression analysis showed that spinal cord area (p = 0.026) was, in fact, the major determinant of outcome and, indeed, of long-term survival (p = 0.001). The mean spinal cord area of those patients not achieving a good outcome was 44 mm2. The atlantodens interval (ADI) was not shown to be a significant outcome determinant, which may be explained by the correlation between an increasing vertical translocation and a decreasing ADI (r = 0.4, p = 0.01). Furthermore, as the degree of vertical translocation increased, the space available for the cord was observed to decrease (p = 0.003) commensurate with a reduction in spinal cord area (p = 0.02). Together, these findings strongly argue for earlier surgical intervention, before the development of vertical translocation, permanent neurological damage, and spinal cord atrophy can occur

BACKGROUND: Opinions differ on the timing of surgery for rheumatoid arthritis patients with atlanto-axial subluxation. Some clinicians wait for development of neurological signs; others favour prophylactic fusion and decompression. We examined the results of surgery in relation to neurological state at the time of operation. METHODS: 134 patients underwent surgery for rheumatoid involvement of the cervical spine, after development of objective signs of myelopathy. Surgical outcomes were examined prospectively in two groups-patients who were still ambulant at the time of presentation (Ranawat class III A) and patients who had lost the ability to walk (Ranawat class III B)-by means of neurological and functional grading systems in conjunction with standard measures of postoperative morbidity and mortality. FINDINGS: 58% of the ambulant patients attained Ranawat neurological grades I or II compared with only 20% of the non-ambulant patients (p<0.0001). The non-ambulant group also fared worse in terms of postoperative complication rate, length of hospital stay, functional outcome, and ultimately survival. Radiologically, the non-ambulant patients were characterised by a smaller cross-sectional spinal cord area. INTERPRETATION: The strong likelihood of surgical complications, the poor survival, and the limited prospects for functional recovery in non-ambulant patients make a strong case for earlier surgical intervention. At a late stage of disease most patients will have irreversible cord damage