John R. Johnson

Perioperative Complications of Posterior Lumbar Decompression and Arthrodesis in Older Adults

BACKGROUNDnLumbar arthrodesis is commonly done in elderly patients to treat degenerative spine problems. These patients may be at increased risk for complications because of their age and associated medical conditions. In this study, we examined the rates of perioperative complications associated with posterior lumbar decompression and arthrodesis in patients sixty-five years of age or older.nnnMETHODSnWe reviewed the hospital records of ninety-eight patients who were sixty-five years of age or older when they had a posterior decompression and lumbar arthrodesis with instrumentation, between 1993 and 1995, to treat degenerative disease of the spine. The average age was seventy-two years (range, sixty-five to eighty-four years).nnnRESULTSnPerioperative complications occurred in seventy-eight patients. Twenty-one patients had at least one major complication, and sixty-nine had at least one minor complication. Forty-nine patients had more than one complication. The most common major complication was wound infection (prevalence, 10%), and the most common minor complication was urinary tract infection (prevalence, 34%). The complication rate increased with older age, increased blood loss, longer operative time, and the number of levels of the arthrodesis.nnnCONCLUSIONSnSurgeons should be vigilant about perioperative complications in elderly patients treated with multi-level lumbar decompression and arthrodesis with instrumentation. Elderly patients should be made aware that they are at increased risk for surgical complications because of their age. Attention should be paid to controlling blood loss and limiting operative time.

Perioperative complications of anterior procedures on the spine.

We reviewed the operative and hospital records of 447 patients in order to determine the rates of perioperative complications associated with an anterior procedure on the thoracic, thoracolumbar, or lumbar spine. The anterior procedures were performed to treat spinal deformity or for débridement or decompression of the spinal canal. The diagnostic groups that we studied included idiopathic scoliosis in adolescents or young adults (100 patients), scoliosis in mature adults (sixty-three patients), kyphosis (sixty-one patients), neuromuscular scoliosis (sixty patients), fracture (forty-seven patients), a revision procedure (thirty-nine patients), congenital scoliosis (thirty-six patients), tumor (nineteen patients), vertebral osteomyelitis or discitis (eight patients), and miscellaneous (fourteen patients). Complications occurred in 140 (31 per cent) of the 447 patients and were classified as major or minor. Forty-seven patients (11 per cent) had at least one major complication and 109 (24 per cent) had at least one minor complication. Two patients died, both from pulmonary complications after the operation. The most common type of major complication was pulmonary; the most common type of minor complication was genito-urinary. The adolescent or young adult patients who had idiopathic scoliosis had the lowest rate of complications, and the patients who had neuromuscular scoliosis had the highest. An age of more than sixty years at the time of the operation was associated with a higher risk of complications. The duration of the procedures involving a thoracic approach was shorter than that of those involving a thoracolumbar or lumbar approach; however, the rate of complications was not significantly different among the three approaches. Vertebrectomies took longer to perform and were associated with a greater estimated blood loss than discectomies; however, there was no significant difference in the rate of complications between the two types of procedures. The patients who had a fracture or a tumor lost more blood than those from the other diagnostic groups. Blood loss increased as the duration of the operation increased for all procedures. Combined anterior and posterior procedures performed during the same anesthesia session were associated with a higher rate of major complications than were procedures that were staged. A logistical regression analysis showed that the variables that increased the risk of a major complication were an estimated blood loss of more than 520 milliliters and an anterior and posterior procedure performed sequentially under the same anesthesia session. This analysis also demonstrated that the diagnosis of idiopathic scoliosis in adolescents or young adults was associated with a reduced risk of major complications. Compared with other major operations, an anterior procedure on the thoracic, thoracolumbar, or lumbar spine performed for the indications mentioned in this study is relatively safe.

The effect of cigarette smoking and smoking cessation on spinal fusion.

Study Design. The effect of cigarette smoking and smoking cessation on spinal fusion was studied in a retrospective review of 357 patients who had undergone instrumented spinal fusion. Objective To document the widely assumed but unreported benefit of cigarette smoking cessation on fusion rate and clinical outcome after spinal fusion surgery. Background Data. Cigarette smoking has been shown to inhibit lumbar spinal fusion and to adversely effect outcome in treatment of lumbar spinal disorders. Prior reports have compared smokers and nonsmokers, as opposed to comparing smokers and quitters. Methods. This study retrospectively identified 357 patients who underwent a posterior instrumented fusion at either L4–L5 or L4–S1 between 1992 and 1996. Analysis of the medical record and follow-up telephone surveys were conducted. Clinical outcome and fusion status was analyzed in relation to preoperative and postoperative smoking parameters. Results. In this study, the nonunion rate was 14.2% for nonsmokers and 26.5% for patients who continued to smoke after surgery (P < 0.05). Patients who quit smoking after surgery for longer than 6 months had a nonunion rate of 17.1%. The nonunion rate was not significantly affected by either the quantity that a patient smoked before surgery or the duration of preoperative smoking abatement. Return-to-work was achieved in 71% of nonsmokers, 53% of nonquitters, and 75% of patients who quit smoking for more than 6 months after surgery. Discussion. These results validate the hypothetical assumption that postoperative smoking cessation helps to reverse the impact of cigarette smoking on outcome after spinal fusion.

Salvage of Instrumented Lumbar Fusions Complicated by Surgical Wound Infection

Study Design This study retrospectively reviewed instrumented lumbar fusions complicated by surgical wound infection and managed by a protocol including antibiotic impregnated beads. Objective To evaluate the potential for an acceptable clinical outcome in cases of instrumented lumbar fusion complicated by wound infection. Summary of Background Data Initial studies of pedicle screw instrumentation suggested an increased infection rate versus noninstrumented fusion. The presence of a metallic implant also complicates wound management. Methods Eight hundred fifty‐eight instrumented fusions were reviewed with 22 (2.6%) deep wound infections identified. Analysis included preoperative risk factors, surgical procedure, postoperative course, and clinical outcome. Results Nineteen patients (mean age, 55 years) were reviewed at a minimum of 1 year after surgery. Sixteen (83%) reported significant preoperative health problems. Forty‐seven percent of the patients had three‐ and four‐level fusions. Mean operative time was 342 minutes. Mean estimated blood loss was 1620 mL. Infection was diagnosed at an average of 16 days after surgery with wound drainage as the most common presenting feature. Patients underwent between two and 10 (mean, 4.7) irrigation procedures. Seven patients had other significant noninfectious complications. At follow‐up evaluation, no patient had recurrence of infection. By comparison to preoperative symptoms, 15 patients were improved, three were unchanged, and one deteriorated. Fusion was apparently solid in 14 patients, probable in four patients, and nonunion occurred in one patient. Conclusion Although wound infection is a significant complication, this study suggests that aggressive surgical management can result in preservation of an adequate fusion rate and maintenance of an acceptable postoperative outcome.

A prospective analysis of intraoperative electromyographic monitoring of pedicle screw placement with computed tomographic scan confirmation

Study Design This study analyzed clinical characteristics of scoliosis associated with congenital heart disease. Chest roentgenograms were reviewed to determine frequency, type, onset, and progression of scoliosis associated with congenital heart disease. Objectives To determine which patients with scoliosis and congenital heart disease should be followed-up carefully. Summary of Background Data Although several studies have been reported on scoliosis and congenital heart disease, the etiology of scoliosis in patients with congenital heart disease is still unknown. Furthermore, it has been difficult to determine the progression of scoliosis. Methods Chest roentgenograms of 680 patients who underwent cardiac operations because of congenital heart disease were evaluated. Results Seventy-four (10.9%) of these patients had scoliosis of more than 10°, although most of them had mild curves. Scoliosis in patients under 10 years old undergoing cardiac operations was more severe than in those older than 10 years who underwent surgery. Scoliosis associated with congenital heart disease showed no particular features. Patients with patent ductus arteriosus showed left convex, high thoracic scoliosis after surgery. Conclusions The mechanisms of onset of scoliosis in patients with congenital heart disease were not simple and were affected by several factors, including age at operation, side of approach, and type of congenital heart disease.Study design. In a prospective study of 90 patients undergoing lumbar pedicle screw instrumentation, 512 screws were tested intraoperatively using electrical stimulation. The accuracy of this technique was verified after surgery by computed tomography. Objectives. Computed tomographic scans taken after surgery were used to evaluate the efficacy of intraoperative screw stimulation and electromyographic monitoring of pedicle screw placement. Summary of Background Data. Previous cadaveric and clinical studies showed the risk of pedicle screw malposition and the inadequate reliability of intraoperative radiographs to identify misplaced screws. Methods. Screws (total, 512) in 90 patients were stimulated intraoperatively, and stimulation threshold was recorded. Computed tomographic scans were taken after surgery to document pedicle screw position. Electromyographic thresholds and computed tomographic data were evaluated independently and compared to assess the accuracy of the electromyographic screw stimulation technique. Results. Intraoperative screw stimulation was extremely accurate in confirming the adequacy of screw position. A stimulation threshold greater than 15 mA provided a 98% confidence that the screw was within the pedicle. In eight of 90 patients (9%), electromyographic monitoring detected a screw malposition that was not identified on lateral radiograph. Conclusions. Screw stimulation monitoring is a valuable and efficacious adjunct to lumbar pedicle screw instrumentation. A stimulation threshold greater than 15 mA reliably indicates adequate screw position. A stimulation threshold between 10 and 15 mA was generally associated with adequate screw position, although exploration of the pedicle is recommended. A stimulation threshold less than 10 mA was associated with a significant cortical perforation in most instances

Lumbar fusion outcomes stratified by specific diagnostic indication.

BACKGROUNDnOne of the primary difficulties in evaluating the effectiveness of lumbar fusion is that, with the exception of spondylolisthesis, specific diagnostic indications for surgery are poorly defined. Diagnostic specificity beyond the symptom of low back pain or the presence of lumbar degeneration needs to be delineated such that outcomes data can be effectively translated into clinical decision making or evidence-based guidelines.nnnPURPOSEnThe purpose of this study was to report on prospectively collected clinical outcome measures, stratified by diagnosis, among a series of patients with lumbar degenerative disease whose treatment included lumbar spine fusion.nnnSTUDY DESIGNnDemographics, diagnostic categorization, and clinical outcome measures were prospectively collected by six spine surgeons at a single tertiary spine center, as part of the surgeons standard clinical practice.nnnPATIENT SAMPLEnFour hundred and twenty-eight patients were enrolled in the study and complete 1- and 2-year Health-Related Quality of Life (HRQOL) data were available in 327 patients whose treatment included decompression and posterolateral lumbar fusion.nnnOUTCOME MEASURESnThe Oswestry Disability Index (ODI), Short Form-36 (SF-36), numeric rating scales for back pain and leg pain.nnnMETHODSnPreoperative diagnosis was classified, in the primary surgical cases, as disc pathology, spondylolisthesis, instability, stenosis, or scoliosis. In revision cases, the diagnosis was classified as nonunion, adjacent level degeneration, or postdiscectomy revision. Patient-reported outcomes at 1 and 2 years post-op were assessed based on diagnostic stratification. Statistical evaluation of clinical outcome was performed for both mean net change in outcome scores and the percentage of patients reaching a minimum clinically important difference (MCID) threshold for each outcome measure.nnnRESULTSnPreoperative diagnosis was spondylolisthesis (n=80), scoliosis (n=17), disc pathology (n=33), instability (n=21), stenosis (n=46), postdiscectomy revision (n=67), adjacent level degeneration (n=40), or nonunion (n=23). Evaluation of 2-year post-op HRQOL measures by diagnostic subgroup revealed the most substantial improvement in ODI score for patients with spondylolisthesis (22.7 points) and scoliosis (21.2 points). Patients with the diagnosis of disc pathology (16.2 points), postdiscectomy revision (14.0 points), instability (12.7 points), stenosis (10.6 points), and adjacent level degeneration (9.5 points) demonstrated a progressively smaller magnitude of ODI improvement. The least ODI improvement at 2 years after surgery was seen in patients with nonunion of a prior fusion (5.5 points). The percentage of patients reaching MCID for ODI at 2 years post-op ranged from 71.0% in the spondylolisthesis subgroup to 34.8% in the nonunion subgroup. The greatest SF-36 physical component score improvement at 2-year follow-up was seen in patients with disc pathology (7.9 points) and spondylolisthesis (7.7 points), followed by scoliosis (6.6 points) and stenosis (6.5 points), instability (5.6 points), postdiscectomy revision (5.3 points) nonunion (3.1 points) and adjacent level degeneration (2.5 points). No significant changes from Year 1 to Year 2 were noted in any of the subgroups. For SF-36 physical component score, percentage of patients reaching MCID ranged from 63.6% in the disc pathology subgroup to 25% in the nonunion subgroup.nnnCONCLUSIONSnThis study supports the concept that added diagnostic specificity is a critical component in building an improved evidence base for lumbar fusion surgery. The magnitude of HRQOL improvement was not equal among diagnostic subgroups. The percentage of patients reaching an MCID level of improvement was also significantly influenced by diagnostic stratification. Without diagnostic specificity for entities beyond spondylolisthesis, the absence of well-defined study populations will continue to limit our ability to move toward evidence-based decision making.

Treatment of Pyogenic Vertebral Osteomyelitis With Anterior Debridement and Fusion Followed by Delayed Posterior Spinal Fusion

Study Design. Case series. Objectives. The results of surgical treatment of osteomyelitis with anterior debridement and fusion followed by delayed posterior stabilization and fusion are presented. Methods. Forty-two patients with vertebral osteomyelitis are presented. There were 5 cervical, 12 thoracic, 1 thoracolumbar, 19 lumbar, and 5 lumbosacral lesions. The most frequently identified organism was Staphylococcus aureus. Most patients had significant comorbidities, including diabetes, or were immunocompromised. Ninety percent had elevated erythrocyte sedimentation rates and C-reactive proteins, while white blood cell counts were less reliably elevated. Imaging studies included radiographs, CT scans, and MRIs. All patients were treated with anterior debridement and strut grafting followed by 14.4 days of intravenous antibiotics and delayed instrumented posterior fusions and received 6 weeks of intravenous antibiotics after surgery. Results. All patients had resolution of their infections with no recurrence. There were two deaths. Neurologic deficits resolved in all patients. The diagnosis of pyogenic vertebral osteomyelitis is frequently delayed and presents a significant surgical challenge. The indications for surgical debridement were neurologic compromise, failed medical treatment, soft tissue extension, extensive vertebral body and disc space destruction, and progressive deformity. Many of these patients were severely ill at presentation and required urgent treatment. Anterior debridement and fusion followed by intravenous antibiotics allows for restoration of anterior column support and control of the infection before posterior instrumentation and fusion. Conclusion. This study demonstrates that anterior surgical debridement with fusion, followed by a period of intravenous antibiotics and delayed instrumented posterior fusion, is highly effective in the treatment of pyogenic osteomyelitis that has failed medical management.

Initial Fusion Rates With Recombinant Human Bone Morphogenetic Protein-2/compression Resistant Matrix and a Hydroxyapatite and Tricalcium Phosphate/collagen Carrier in Posterolateral Spinal Fusion

Study Design. Prospective, randomized, unblinded study of iliac crest bone graft (ICBG) versus recombinant human bone morphogenetic protein-2/compression resistant matrix (rhBMP-2/CRM)in a posterolateral instrumented fusion procedure. Objectives. Document initial radiographic characteristics, based on computed tomography, with rhBMP-2/CRM for posterolateral fusion at 6 and 12-month intervals. Summary of Background Data. As the acceptance of INFUSE bone graft as an ICBG replacement becomes more widespread, surgeons have begun to study applications for rhBMP-2 in posterior spinal fusion. Preclinical studies have examined variables including carrier composition, rhBMP-2 concentration, and rhBMP-2 dose. Pilot studies have been performed with encouraging initial results. Methods. Patients with single level lumbar degenerative disease were enrolled in a randomized study of ICBG versus rhBMP-2/CRM in a posterolateral instrumented fusion procedure. Computed tomography scans at 6 and 12 months were graded as demonstrating no fusion (grade 1), partial or limited unilateral fusion (grade 2), partial or limited bilateral fusion (grade 3), solid unilateral fusion (grade 4), or solid bilateral fusion (grade 5). Results. At our institution, 74 patients (38 rhBMP-2/CRM, 36 ICBG) reached minimum 1-year follow-up and were included in this analysis. Mean fusion grade (scale1–5) at 6 months after surgery was 4.35 in the rhBMP-2/CRM group versus 3.09 in the ICBG group (P < 0.0001). At 1 year after surgery mean fusion grade was 4.62 in the rhBMP-2/CRM group versus 3.77 in the ICBG group (P < 0.0023). Conclusions. These early results are encouraging and suggest a more rapid incorporation and development of the fusion mass with rhBMP-2/CRM than iliac crest autograft in a single level posterior instrumented fusion.

RhBMP-2 Versus Iliac Crest Bone Graft for Lumbar Spine Fusion : A Randomized, Controlled Trial in Patients Over Sixty Years of Age

Study Design. Prospective randomized controlled trial of rhBMP-2/ACS (Infuse bone graft) versus iliac crest bone graft (ICBG) for lumbar spine fusion in patients over 60 years of age. Objective. To report on clinical, radiographic, and economic outcomes, at 2-year follow-up, in patients treated by posterolateral lumbar fusion with rhBMP-2/ACS versus ICBG. Summary of Background Data. RhBMP-2/ACS is widely used “off-label” for posterolateral spinal fusion. Despite encouraging initial reports, outstanding issues include the need for evidence regarding safety and efficacy in an older population; and an assessment of cost-effectiveness. Methods. Patients over 60 years old were randomized to rhBMP-2/ACS (n = 50) or ICBG (n = 52). Oswestry Disability Index, Short Form-36, and numerical rating scales for back and leg pain were determined preoperatively and at 6, 12, and 24 months postoperatively. Fusion was evaluated by fine-cut computed tomography scan 2 years postoperatively by 3 reviewers. All in-patient and subsequent out-patient event costs were recorded by a dedicated hospital coder. Results. Two-year postoperative improvement in Oswestry Disability Index averaged 15.8 in the rhBMP-2/ACS group and 13.0 in the ICBG group. Mean improvement in Short Form-36 physical component score was 6.6 in the rhBMP-2/ACS group and 7.5 in the ICBG group. There were 20 complications in the ICBG group and 8 complications in the rhBMP-2/ACS group (P = 0.014). Sixteen ICBG and 10 rhBMP-2/ACS patients required additional treatment for persistent back or leg symptoms. Two rhBMP-2/ACS patients had revision procedures, 1 for nonunion. Eight patients in the ICBG group had revision procedures, 5 for nonunion. Mean fusion grade on computed tomography scan was significantly (P = 0.030) better in the rhBMP-2/ACS (4.3) compared with the ICBG group (3.8). Mean cost of the initial admission was

Long-term Effects of Tibial Angular Malunion on the Knee and Ankle Joints

36,530 in the rhBMP-2/ACS group and