5-year reoperation rates after different types of lumbar spine surgery

STUDY DESIGN: Population-based cohort study of Washington State patients who underwent lumbar spine surgery for degenerative conditions in 1988. OBJECTIVES: To compare complications and reoperation rates during the 5-year period after surgery between patients who have undergone lumbar spine fusion surgery and those who have undergone laminectomy or discectomy alone. SUMMARY OF BACKGROUND DATA: Spinal fusion is associated with wider surgical exposure, more extensive dissection, and longer operative times than lumbar surgery without fusion, and previous studies have shown higher complication rates and hospital charges associated with these more complex procedures. In elderly patients, spinal fusion operations were associated with higher mortality rates than laminectomy or discectomy alone, and reoperation rates were not lower. In the current study, reoperations, mortality, and complications following lumbar spine surgery were examined for the general population. METHODS: A statewide hospital discharge database was used to identify all Washington patients who underwent spine surgery in 1988 and to determine the rate of reoperation during the subsequent 5 years. Administrative records also were used to identify complications, mortality, and hospital charges associated with the operations. Unadjusted complication and reoperation rates for the groups were compared using chi-square statistics. Adjusted rates were compared using logistic regression and proportional hazards (Cox) regression after controlling for age, gender, prior spine surgery, diagnosis, comorbidity, type of surgery, and coverage by Workers' Compensation. RESULTS: Of 6376 patients who underwent lumbar surgery for degenerative conditions in Washington in 1988, 1041 (16%) had operations involving spine fusion. Diagnoses of degenerative disc disease or possible instability were more frequent among patients undergoing fusion surgery, whereas herniated discs were more frequent among those undergoing discectomy or laminectomy alone. Complications were recorded in 18% of fusion patients and 7% of nonfusion patients (P < 0.01), but mortality rates did not differ. Unadjusted reoperation rates over the 5-year period were greater for patients who underwent fusion than for patients who underwent nonfusion surgery (18% vs. 15%, respectively), but after adjustment for baseline characteristics, fusion patients had only a slightly greater (and nonsignificant) risk of reoperation (relative risk 1.1, confidence interval .9-1.3). CONCLUSION: As in previous studies, complications in the current study occurred more frequently among patients who underwent lumbar spine fusion than among those who underwent laminectomy or discectomy alone. Reoperations were at least as frequent after fusion, but the authors could not assess treatment efficacy in terms of pain relief or improved function. Although the characteristics of patients undergoing fusion differed from those undergoing a laminectomy or discectomy alone, there appeared to be sufficient overlap in the clinical populations to warrant closer scrutiny of the safety, efficacy, and indications for spinal fusions, preferably in randomized trials.     

Epidemiology of insect venom sensitivity in children and its correlation to clinical and atopic features

STUDY DESIGN: The influence of ketorolac on spinal fusion was studied in a retrospective review of 288 patients who underwent an instrumented spinal fusion. OBJECTIVE: To assess the effect of postoperative ketorolac administration on subsequent fusion rates. SUMMARY OF BACKGROUND DATA: Nonsteroidal anti-inflammatory drugs are widely used compounds, which are known to inhibit osteogenic activity and have been shown to decrease spinal fusion in an animal model. No previous studies have examined the influence of nonsteroidal anti-inflammatory drugs on spinal fusion in clinical practice. METHODS: The medical records of 288 patients who underwent instrumented spinal fusion from L4 to the sacrum between 1991 and 1993 were reviewed retrospectively. The 121 patients who received no nonsteroidal anti-inflammatory drugs were compared with the 167 patients who received ketorolac after surgery. The groups were demographically equivalent. RESULTS: Ketorolac had a significant adverse effect on fusion, with five nonunions in the nondrug group and 29 nonunions in the ketorolac group (P > 0.001). Ketorolac administration also significantly decreased the fusion rate for subgroups including men, women, smokers, and nonsmokers. The odds ratio demonstrated that nonunion was approximately five times more likely after ketorolac administration. Cigarette smoking also decreased the fusion rate (P > 0.01); smokers were 2.8 times more likely to develop nonunion. CONCLUSION: These data suggest that nonsteroidal anti-inflammatory drugs significantly inhibit spinal fusion at doses typically used for postoperative pain control. The authors recommend that these drugs be avoided in the early postoperative period.     

Prospects in video-assisted spinal surgery

Advances in spinal surgery for both posterior procedures on herniated discs and anterior procedures involving the vertebral body have been greatly affected by developments in video-assisted techniques. Many of the procedures mentioned here are still in the development stage, others have proven their efficacy. Discoscopy, achieved by introducing the endoscope via a posterolateral route into the intervertebral disc, can be used for diagnosis and treatment of the disc and the end plates. Other techniques exploring the spinal canal are also being developed. With miniaturization, these techniques will undoubtedly be predominant in the near future. The anterior route is facilitated at the thoracic level by the pleural cavity. Current indications for anterior endoscopic spinal surgery are limited to cord compression syndromes, but perspectives for trauma or tumor surgery as well as reconstruction surgery for malformations in children are quite promising. On the lumbar level, surgery involving the lombo-sacral disc is the main indication for transperitoneal endoscopy. The risks (sepsis, occlusion, gas emboli) cannot be overlooked, but few complications have been observed to date. The retroperitoneal route can be used to approach the anterolateral aspect of the spine, particularly useful for the upper lumbar bodies. A third possibility is the extraperitoneal anterior route for video-assisted procedures from L2-L3 to L5-S1. Although video-assisted procedures have not yet been shown to improve long-term outcome after spinal surgery, the immediate post-operative period is greatly simplified, a point which may be of particular importance depending on the patient's general status.     

Evidence for eosinophil activation in bronchiectasis unrelated to cystic fibrosis and bronchopulmonary aspergillosis: discrepancy between blood eosinophil counts and serum eosinophil cationic protein levels

The purpose of this prospective study was to evaluate the effect of prophylactic antibiotic treatment on postoperative antibiotic spinal wound infection after spinal surgery with instrumentation. Subjects consisted of 110 successive patients that underwent instrumented fusion with Cotrel-Dubousset (CD) or Miami Moss instrumentation. In 56 cases, the indication for surgery was painful spondylolisthesis. The remaining 54 patients were treated for idiopathic scoliosis. In total, 172 spinal procedures were performed and included in the study. Preoperative infection prophylaxis consisting of 2 g cefamandole was administered to all patients. Patients received three doses of 2 g/day cefamandole after surgery for 3 days. Follow-up ranged from 1 to 4 years. The study revealed an early infection in one (0.6%) of the 172 procedures in a patient with spondylolisthesis. A late infection occurred in one (0.6%) patient with the diagnosis of idiopathic scoliosis. In both cases, cultures were positive for Staphylococcus aureus.     

Pseudarthrosis of the lumbar spine. Outcome after circumferential fusion

STUDY DESIGN: Twenty-five patients with a pseudarthrosis after previous spinal fusion surgery were reviewed after a circumferential fusion was performed. OBJECTIVES: To determine the fusion rate and its relation to outcome, i.e., pain reduction and return to work, and associated complications. SUMMARY OF BACKGROUND DATA: Circumferential fusion has become a common procedure with more patients undergoing multiple operations. This operation is thought to improve the fusion rate with a low complication rate. However, the procedure has not been evaluated specifically for the management of pseudarthrosis. METHODS: Twenty-five patients were reviewed regarding age, gender, smoking status, previous back surgeries, extent of leg and back pain, occupation, levels of surgery, type of instrumentation, blood loss, and complications. A minimum follow-up period of 2 years included evaluation of radiographs, pain levels, medication, and return to work. RESULTS: Twenty percent of patients were heavy smokers. An average of 2.2 previous procedures had been performed, and the average follow-up period was 2.7 years. Eighty percent of patients underwent multiple-level fusions. A solid fusion was achieved in 100%. Complications included two painful instrumentation devices requiring removal, one retroperitoneal hematoma, one anterior abdominal wall dehiscence, and one case of pneumonia. Pain scores improved from 7.4 to 4.7 for back pain, and 5.4 to 2.8 for leg pain, respectively. Both improvements were statistically significant (P < 0.01 and 0.003, respectively). However, only 52% of patients reduced their pain by a full category. Forty-one percent were still taking narcotics intermittently or consistently, and 53% returned to work or were actively seeking employment. DISCUSSION: A fusion rate of 100% was noted in the face of factors often placing patients at high risk for developing a pseudarthrosis, namely multiple levels of previous spinal surgery, including previous pseudarthrosis, and a habit of heavy smoking. Complications were few. However, the satisfactory outcome rate was only somewhat better than 50%, based on a lack of substantial pain improvement and return to work.     

Occipitocervical fusion with C1 laminectomy in children

STUDY DESIGN: Eight children in whom atlantoaxial dislocation had developed underwent occipitocervical fusion using a rectangular rod. The postoperative results are presented, and the postoperative growth and deformation of the cervical spine were determined radiographically. OBJECTIVES: To investigate in a relatively long-term follow-up study whether occipitocervical fusion affects the growth of the cervical spine and induces spinal deformation. SUMMARY OF BACKGROUND DATA: It has been reported that children who have undergone C1-C2 posterior fusion are likely to develop abnormal curvature or deformation of the cervical spine as a result of a disturbance of growth of the fused vertebrae. There have been no studies, however, to confirm that these changes occur after occipitocervical fusion in children. METHODS: The subjects were one boy and seven girls who had undergone occipitocervical posterior fusion during childhood. The average age at the time of surgery was 8.3 years, and the average follow-up period was 5.9 years. The following were assessed radiographically: redislocation of the atlas, bone union, changes in the curvature of the cervical spine, the height and width of the vertebral bodies, and the anteroposterior diameter of the spinal canal. RESULTS: Solid bone union was achieved in all patients with maintenance of the reduced position at the time of surgery. None of the patients exhibited abnormal curvature of the cervical spine. The rate of increase in height of the C2 vertebral body was significantly less than that of vertebral bodies below C3. The rate of increase in width of the vertebral body and the anteroposterior diameter of the spinal canal of the C2 vertebral body and vertebral bodies below C3 did not differ significantly. CONCLUSIONS: Occipitocervical fusion with a rectangular rod is useful for treating atlantoaxial dislocation in children and yields excellent results because of the firm internal fixation it achieves. This surgery induced no apparent postoperative spinal deformations.     

Management of iatrogenic spinal stenosis complicating placement of a fusion cage. A case report

STUDY DESIGN: A case of iatrogenic spinal stenosis secondary to fusion cage retropulsion is presented. OBJECTIVES: To highlight fusion cage retropulsion, a potential complication that may become more prevalent as the use of fusion cage instrumentation expands. The difficulty in management of this complication is emphasized. SUMMARY OF BACKGROUND DATA: Early reports regarding fusion cage instrumentation have been encouraging. At this point, however, the potential benefits are better defined than the potential complications. METHODS: A significant complication of fusion cage instrumentation and the limited literature on this subject are reviewed. RESULTS: The patient underwent successful revision surgery after retropulsion of a fusion cage, however, an extensive surgical procedure including partial vertebral body resection was required. CONCLUSIONS: The frequency and severity of complications related to fusion cage instrumentation remain poorly defined. Caution should be used in patient selection until additional experience more clearly defines the risk-to-benefit ratio for a given application of this new technology.     

Comparison of the use of supine bending and traction radiographs in the selection of the fusion area in adolescent idiopathic scoliosis

STUDY DESIGN: A study was done to evaluate the use of voluntary supine side bending radiographs and Risser table traction radiographs in adolescent patients undergoing posterior spinal fusion for idiopathic scoliosis. OBJECTIVES: To compare the usefulness of supine side bending and traction radiographs in assessing curve flexibility and determining fusion levels in patients undergoing posterior spinal fusion for adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Supine side bending radiographs have been used in the preoperative evaluation of idiopathic scoliosis to determine curve flexibility and fusion area. Traction films have been used to determine the flexibility of large curves and neuromuscular curves where active side bending is not possible. No study to date has compared the use of these films in patients with adolescent idiopathic scoliosis undergoing surgery. METHODS: Seventy-five patients with more than a 2-year follow-up period after surgery were included in this study. Preoperative radiographs included a standing posteroanterior and lateral film and both supine maximal voluntary side bending films and a traction film done on a Risser table. A preoperative review of these radiographs was done to determine curve flexibility and fusion levels. At follow-up evaluation, the patients were examined for any evidence of decompensation or "adding-on" of levels. RESULTS: For curves less than 60 degrees, side bending radiographs showed greater curve correction than traction radiographs, whereas the opposite was true for curves greater than 60 degrees. For King I and II curves, side bending radiographs were superior for determination of lumbar curve flexibility and for distinguishing these two types of curves. On traction radiographs, the stable vertebra was 1.4 vertebral levels higher than on the standing film. When the fusion level was moved proximally because of the traction radiograph, decompensation or "adding-on" commonly occurred. CONCLUSIONS: Supine bending radiographs are superior to traction radiographs for assessing curve flexibility except for curves more than 60 degrees. The selection of the distal extent of fusion based on the traction radiograph gave a large number of poor results. The selection of fusion levels in adolescent Idiopathic scoliosis is best determined by a combination of standing posteroanterior and lateral radiographs and the supine maximum voluntary bend films.     

Universal calibration of surgical instruments for spinal stereotaxy

PURPOSE: To describe new software applications and interchangeable instrumentation enabling the use of standard surgical instruments with image-guided systems for stereotactic spinal procedures. CONCEPT: The ability to adapt essentially any surgical instrument for stereotactic procedures will improve the safety and accuracy of image-guided spinal surgery. RATIONALE: Using universal dynamic registration hardware and software, standard surgical instruments are adapted for real-time image-guided surgery. The Radionics Optical Tracking System (Radionics, Inc., Burlington, MA) has custom software applications and universal hardware adaptation devices for spinal stereotaxy that allows the use of standard instruments for intraoperative guidance. An array of light-emitting diodes can be attached to essentially any rigid instrument with a definable tip and can then be calibrated to the system for intraoperative use. Stereotactic guidance of a drill, tap, and screwdriver may improve screw placement accuracy in spinal surgery because every step of the procedure can be monitored in real time. DISCUSSION: Most stereotactic systems have only a standard probe or limited instruments for localization, targeting, and tracking a procedure. The surgeon then resumes the operation using standard surgical instruments without the benefit of image guidance for the key steps of the procedure. Because each surgical step for screw placement in the spine has a potential for error, use of multiple instruments that can be interchanged for real-time image-guided spinal surgery may increase the accuracy and safety of spinal instrumentation procedures. These techniques can also be applied to intracranial image-guided surgery.     

Results and morbidity in a consecutive series of patients undergoing spinal fusion for neuromuscular scoliosis

STUDY DESIGN: A retrospective clinical and radiographic review. OBJECTIVES: To provide current data on the results and complications of patients who have undergone spinal fusion for neuromuscular scoliosis at a center with physicians experienced in these types of cases. SUMMARY OF BACKGROUND DATA: The reported complication rate in the management of neuromuscular scoliosis ranges from 44% to 62% in the recent literature. This literature is that of 1991 or earlier reflecting operative techniques of the mid-1980s, and it has been used to argue against the efficacy of neuromuscular spinal fusions. METHODS: A retrospective chart and radiographic review of 50 consecutive spinal fusions for neuromuscular scoliosis was performed at Connecticut Children's Medical Center between January 1990 and January 1994. The three most common diagnoses were spastic quadriplegic cerebral palsy (20 patients), myelomeningocele (13 patients), and muscle disease (8 patients). There were 38 posterior spinal fusions including two kyphectomies and 12 anteroposterior spinal fusions. The Luque-Galveston technique was used in 39 of 50 patients. The average age at surgery was 13 years and 6 months, with an average follow-up of 40 months (minimum, 24 months). RESULTS: Before surgery, the mean major scoliosis measured 72 degrees, with mean best bend or traction view of 35 degrees. At most recent follow-up, the mean scoliosis magnitude was 25 degrees (mean correction, 65%). There were 17 minor complications in 14 patients and three major complications (deep wound infections) in three myelomeningocele patients. Rod breakage was noted in two patients, one of whom had an asymptomatic pseudarthrosis. There were no neurologic complications or deaths, and none of the complications affected the final results. CONCLUSIONS: The data in the current study support the authors' belief that with current surgical techniques and perioperative management in an experienced center, the results for patients undergoing spinal fusion for neuromuscular scoliosis have been improved, and major complications have been minimized.     

Adjacent-segment degeneration after lumbar fusion with instrumentation: a retrospective study

Adjacent-segment degeneration is a known consequence of spinal fusion. Factors associated with this, and its effect on results, have not been well identified. This study sought to determine factors associated with adjacent-segment degeneration and the effect this degeneration has on results after lumbar fusion and instrumentation. Forty-nine patients were retrospectively reviewed after lumbar fusion with instrumentation and analyzed for adjacent-segment degeneration. Adjacent-segment degeneration occurred in 17 (35%) patients and was associated with increasing patient age, the use of interbody fusion, and a worsening of clinical results with time. In older patients with stenosis, it was associated with previous surgery. This should be considered when choosing operative techniques in treating lumbar pathologic conditions, especially in older patients.     

Reliability of spinal displacement analysis of plain X-rays: a review of commonly accepted facts and fallacies with implications for chiropractic education and technique

BACKGROUND: Current medical, biomechanical, and chiropractic literature indicates that X-ray line drawing analysis for spinal displacement is reliable, with high Interclass Correlation Coefficients (ICCs) found in most studies. Normal sagittal spinal curvatures are being accepted as important clinical outcomes of care; however, just the opposite is taught in many chiropractic college radiology courses. OBJECTIVE: To review the current literature on X-ray line drawing reliability and abnormal static lateral positions. DATA SOURCES: Searches were performed on Medline, Chiro-LARS, MANTIS, and CINAHL on X-ray reliability, normal spinal position, and sagittal spinal curvatures as clinical outcomes. RESULTS: X-ray line drawing analysis for spinal displacement was found to have high reliability with a majority of ICCs in the .8-.9 range. The reliability for determining X-ray pathology was found to be only fair to good by both medical doctors and chiropractors and by both chiropractic and medical radiologists, with a majority of ICCs in the range .40-.75. Muscle spasms, facet hyperplasia, short pedicles and patient positioning errors have not been shown to alter sagittal plane alignment. The sagittal spinal curves are desirable clinical outcomes of care in surgery, physical therapy, rehabilitation and chiropractic. These results contradict common claims found in the indexed literature. CONCLUSION: X-ray line drawing is reliable. Normal values for the sagittal spinal curvatures exist in the literature. The normal sagittal spinal curvatures are important clinical outcomes of care. Patient positioning and postural radiographs are highly reproducible. When these standardized procedures are used, the pre-to-post alignment changes are a result of treatment procedures applied. Chiropractic radiology education and publications should reflect the recent literature, provide more support for X-ray line drawing analyses and applications of line drawing analyses for measuring spinal displacement on plain radiographs.     

Dorsal hemivertebrae in children's lumbar spines

STUDY DESIGN: Only small numbers patients with dorsal hemivertebrae have been reported. The natural course of this disease remains unpredictable, especially regarding the development of neurologic impairment. Two children with congenital dorsal hemivertebra with progressive kyphosis of the lumbar spine are presented. Onset and method of treatment are discussed. OBJECTIVES: Two boys with kyphosis due to dorsal hemivertebrae of the lumbar spine were followed with clinical examination, anteroposterior roentgenograms, and magnetic resonance imaging. One patient was in follow-up for more than 4 years postoperatively. The other patient, who has not undergone surgery, has been in follow-up for more than 2 years, undergoing reassessment every 4 to 6 months. SUMMARY OF BACKGROUND DATA: Spastic paralysis developed in one patient with dorsal hemivertebra and spina bifida. The other patient with dorsal hemivertebra and sacral agenesis had no neurologic deficit. METHODS: A dorsal approach with resection of the dorsal hemivertebra and short dorsal fusion with internal fixation was done in one patient. The other patient underwent clinical and radiologic follow-up. Method and onset of surgical treatment were compared with other studies. RESULTS: Progressive spasticity was seen in our first patient. This could be reversed by resection of the hemivertebra and monosegmental fusion. Alignment of the spine and normalization of the width of spinal canal were achieved. The second patient has not had a neurologic problem. Surgical treatment will be performed when indicated. CONCLUSIONS: A posterior approach is recommended for a dorsal hemivertebra. Decompression of the spinal canal can be achieved by resection of the dorsal hemivertebra and short dorsal fusion with internal fixation. Surgery should be done early to avoid late neurologic impairment.     

Surgical treatment of lumbar spinal stenosis in the elderly

148 elderly patients, aged 70 years or more, diagnosed as having lumbar spinal stenosis, were operated upon at our institution during 1983 to 1995. Totally 161 operative procedures were performed. We analysed retrospectively the results of the surgical treatment. The most frequently performed procedure was multisegmental laminectomy, in 32% interlaminar fenestration and laminotomy were done. In 9 cases fusion was indicated, two of them being secondary operations. The mean hospital stay was 11 days. The morbidity was 6%, and there was one fatality (0.6%). The outcome was determined according to the six-grade classification proposed by Pappas and Sonntag [25]. Overall, in 91% of cases satisfactory-to-excellent results could be achieved. We conclude, that in elderly patients with symptomatic lumbar spinal stenosis, with no evidence of instability, decompressive surgery without stabilisation can be done in the majority of patients with low morbidity and high expectation of clinical improvement.     

Application of thoracoscopy for diseases of the spine

For anterior approaches to the thoracic spine, a posterolateral thoracotomy has been the standard approach. Recent expanded experience with video-assisted thoracic surgical techniques has allowed us to perform many thoracic spine procedures that previously required open approaches. These procedures include drainage of spinal abscesses, biopsy of vertebral bodies, discectomy for a herniated nucleus pulposus, and anterior releases for kyphoscoliosis. All procedures were successful, but experience is limited and follow-up still short. It is hoped that further experience will prove that this less invasive approach can be widely applied in the practice of thoracic spinal surgery.     

Complications during and after surgery and childbirth where spinal or epidural analgesia is used. Guidelines for safe practice

When complications and neurological sequelae occur during a spinal or epidural anaesthetic the causes are clearly related to the procedures in the following cases: severe haemodynamic or respiratory derangement, documented needle trauma of nerve fibres, intraspinal haematoma in anticoagulated or heparinized patients, and epidural infection where an infected epidural catheter entry site is documented. A number of well documented cases have been published in which surgery or patient-related pathology were primary causes of "typical" spinal or epidural neurological complications. These emphasize the importance of searching for other risk factors of neurological sequelae after surgery or child birth in cases where there is no obvious deviation from the normal epidural or spinal procedures. Increased focus on the infrequent, but serious complications of these essentially very safe techniques for surgical anaesthesia and pain relief should serve to increase our vigilance, but should not reduce the application of spinal and epidural analgesia. Guidelines are offered for the effective and safe practice of spinal and epidural anaesthesia and pain relief: adequate supervision of trainee anaesthetists, vigilant monitoring for early detection and handling of complications, and trained nurses on surgical wards to monitor and handle patients during epidural analgesia are important. Sufficient readiness for urgent handling of the very rare, but devastating complications of intraspinal bleeding or infection is an absolute necessity.     

Neuromuscular scoliosis: a case of the pediatric patient in the adult ICU

Neuromuscular scoliosis can be a problem in children with underlying neuromuscular conditions such as cerebral palsy, spina bifida, and muscular dystrophy. A comprehensive preoperative assessment is essential to provide comprehensive postoperative care. Surgical procedures to correct neuromuscular scoliosis include anterior spinal fusion, posterior spinal fusion, or a combined anterior-posterior spinal fusion. Postoperative problems can include respiratory failure, hemodynamic instability, neurovascular compromise, and pain control. With an understanding of the developmental status of these patients, pediatric patients can be safely managed in an adult ICU.     

Obstetric cholestasis

The field of orthopaedic surgery has changed rapidly in the last ten years, increasing the demand for a readily available supply of allograft. Historically, bone was first grafted in 1668. The first clinical allograft was performed in 1820 by Phillips von Walter who reconstructed part of a skull. Clinical use of allograft has developed steadily during this century, making it now an essential requirement in orthopaedic surgery. Nationally, there is a shortage of available allograft for orthopaedic procedures. Allograft bone can be used in spinal fusion, filling of bone cysts, non-union of fractures and, most commonly, in revision joint replacements. In the last twenty years joint replacement surgery has become common practice and the number of patients requiring revision joint surgery has also increased. This expansion will continue owing to the growing demands made on our health service by our increasingly elderly population. We can expect an increase in demand for allograft.     

Failure of a carbon fiber implant. A case report

STUDY DESIGN: Case report. OBJECTIVES: Failure of a carbon fiber implant. SUMMARY OF BACKGROUND DATA: To simplify the procedure of posterior lumbar interbody fusion, a carbon-fiber-reinforced polymer implant has been developed. The implant has ridges to resist retropulsion, struts to support weight, and a hollow area to allow packing of autologous bone graft. So far, no complications have been reported from the use of carbon implant as a fusion aid in spine surgery. METHODS: A patient with postoperative infection has been followed with computed tomography images and histologic examination from a reoperation. RESULTS: An entire nonunion across the width of the disc space and a clearly broken cage was visualized with computed tomography. The spinal canal was explored during a reoperation and the tissue surrounding the dura and nerves were all black. Microscopic examination showed a large quantity of carbon particulate debris. The authors have operated on approximately 100 patients so far and no other carbon cage has broken, to their knowledge. CONCLUSIONS: Carbon cages can break if a nonunion occurs and as a result free carbon particles move out to the spinal canal.