Joseph H. Perra

Complications Associated with Pedicle Screws

BACKGROUND The safety and the effectiveness of pedicle-screw instrumentation in the spine have been questioned despite its use worldwide to enhance stabilization of the spine. This review was performed to answer questions about the technique of insertion and the nature and etiology of complications directly attributable to the screws. METHODS We performed a retrospective review of all of the pedicle-screw procedures that were done by us from January 1, 1984, to December 31, 1993. We inserted 4790 screws during 915 operative procedures on 875 patients; 668 (76.3 percent) of the patients had a lumbosacral arthrodesis. The mean duration of follow-up was three years (range, two to five years). The accuracy of screw placement was assessed on intraoperative, immediate postoperative, and follow-up radiographs with use of a technique that was developed by one of us (F. D.); this technique has yet to be validated to determine the prevalence of various types of error. RESULTS Of the 4790 screws, 4548 (94.9 percent) had been inserted within the pedicle and the vertebral body. One hundred and thirty-four (2.8 percent) of the screws had perforated the anterior cortex, and this was the most common type of perforation. One hundred and fifteen (2.4 percent) of the screws were associated with complications that could be ascribed to the use of pedicle screws. The most common problem was late-onset discomfort or pain related to a pseudarthrosis or perhaps to the screws; this problem was associated with 1102 (23.0 percent) of the screws, used in 222 (24.3 percent) of the procedures. The symptoms necessitated removal of the instrumentation with or without repair of the pseudarthrosis. A pseudarthrosis was found during forty-six (20.7 percent) of the 222 procedures. Irritation of a nerve root occurred after nine procedures (1.0 percent) and was caused by eleven screws (0.2 percent); it was more commonly caused by medially placed screws. Three patients had residual neurological weakness despite removal of the screws. Twenty-five screws (0.5 percent), used in twenty procedures (2.2 percent), broke. The screws that broke were of an early design. A pseudarthrosis was found in thirteen of twenty patients who had broken screws. Sixteen of the twenty patients had an exploration; three of them were found to have a solid fusion, and thirteen were found to have a pseudarthrosis. The remaining four patients had evidence of a solid fusion on radiographs and had no pain. CONCLUSIONS There are few problems associated with the insertion of screws, provided that the surgeon is experienced and adheres to the principles and details of the operative technique. Our review revealed a low rate of postoperative complications related to pedicle screws. The problem of late-onset pain may be related to the implants or to the stiffness of the construct; however, it is difficult to accurately identify its exact etiology.

Complications in spinal fusion for adolescent idiopathic scoliosis in the new millennium. A report of the Scoliosis Research Society Morbidity and Mortality Committee.

Study Design. The Morbidity and Mortality database of the Scoliosis Research Society (SRS) was queried as to the incidence and type of complications as reported by its members for the treatment of adolescent idiopathic scoliosis (AIS) with spinal fusion and instrumentation procedures regarding surgical approach (anterior, posterior, or combined anterior-posterior) during a recent 3-year period. Objective. To evaluate the incidence of surgeon-reported complications in a large series of spinal fusions with instrumentation for a single spinal deformity diagnosis and age group regarding surgical approach. Summary of Background Data. The SRS has been collecting morbidity and mortality data from its members since its formation in 1965 with the intent of using these data to assess the complications and adverse outcomes (death and/or spinal cord injury) of surgical treatment for spinal deformity. Surgical approaches to the management of treatment of AIS have a measurable impact on efficacy of correction, levels fused, and operative morbidity. However, there is a lack of consensus on the choice of surgical approach for the treatment of spinal deformity. Methods. Of the 58,197 surgical cases submitted by members of the SRS in the years 2001, 2002, and 2003, 10.9% were identified as having had anterior, posterior, or combined spinal fusion with instrumentation for the diagnosis of AIS, and comprised the study cohort. All reported complications were tabulated and totaled for each of the 3 types of procedures, and statistical analysis was conducted. Results. Complications were reported in 5.7% of the 6334 patients in this series. Of the 1164 patients who underwent anterior fusion and instrumentation, 5.2% had complications, of the 4369 who underwent posterior instrumentation and fusion, 5.1% had complications, and of the 801 who underwent combined instrumentation and fusion, 10.2% had complications. There were 2 patients (0.03%) who died of their complications. There was no statistical difference in overall complication rates between anterior and posterior procedures. However, the difference in complication rates between anterior or posterior procedures compared to combined procedures was highly significant (P < 0.0001). The differences in neurologic complication rates between combined and anterior procedures, as well as combined and posterior procedures were also highly statistically significant (P < 0.0001), but not between anterior and posterior procedures. Conclusions. This study shows that complication rates are similar for anterior versus posterior approaches to AIS deformity correction. Combined anterior and posterior instrumentation and fusion has double the complication rate of either anterior or posterior instrumentation and fusion alone. Combined anterior and posterior instrumentation and fusion also has a significantly higher rate of neurologic complications than anterior or posterior instrumentation and fusion alone.

Rates of infection after spine surgery based on 108,419 procedures: a report from the Scoliosis Research Society Morbidity and Mortality Committee.

Study Design. Retrospective review of a prospectively collected database. Objective. Our objective was to assess the rates of postoperative wound infection associated with spine surgery. Summary of Background Data. Although wound infection after spine surgery remains a common source of morbidity, estimates of its rates of occurrence remain relatively limited. The Scoliosis Research Society prospectively collects morbidity and mortality data from its members, including the occurrence of wound infection. Methods. The Scoliosis Research Society morbidity and mortality database was queried for all reported spine surgery cases from 2004 to 2007. Cases were stratified based on factors including diagnosis, adult (≥21 years) versus pediatric (<21 years), primary versus revision, use of implants, and whether a minimally invasive approach was used. Superficial, deep, and total infection rates were calculated. Results. In total, 108,419 cases were identified, with an overall total infection rate of 2.1% (superficial = 0.8%, deep = 1.3%). Based on primary diagnosis, total postoperative wound infection rate for adults ranged from 1.4% for degenerative disease to 4.2% for kyphosis. Postoperative wound infection rates for pediatric patients ranged from 0.9% for degenerative disease to 5.4% for kyphosis. Rate of infection was further stratified based on subtype of degenerative disease, type of scoliosis, and type of kyphosis for both adult and pediatric patients. Factors associated with increased rate of infection included revision surgery (P < 0.001), performance of spinal fusion (P < 0.001), and use of implants (P < 0.001). Compared with a traditional open approach, use of a minimally invasive approach was associated with a lower rate of infection for lumbar discectomy (0.4% vs. 1.1%; P < 0.001) and for transforaminal lumbar interbody fusion (1.3% vs. 2.9%; P = 0.005). Conclusion. Our data suggest that postsurgical infection, even among skilled spine surgeons, is an inherent potential complication. These data provide general benchmarks of infection rates as a basis for ongoing efforts to improve safety of care.

Complications in the surgical treatment of 19,360 cases of pediatric scoliosis: a review of the Scoliosis Research Society Morbidity and Mortality database.

Study Design. Retrospective review of a multicenter database. Objective. To determine the complication rates associated with surgical treatment of pediatric scoliosis and to assess variables associated with increased complication rates. Summary of Background Data. Wide variability is reported for complications associated with the operative treatment of pediatric scoliosis. Limited number of patients, surgeons, and diagnoses occur in most reports. The Scoliosis Research Society Morbidity and Mortality (M&M) database aggregates deidentified data, permitting determination of complication rates from large numbers of patients and surgeons. Methods. Cases of pediatric scoliosis (age ⩽18 years), entered into the Scoliosis Research Society M&M database between 2004 and 2007, were analyzed. Age, scoliosis type, type of instrumentation used, and complications were assessed. Results. A total of 19,360 cases fulfilled inclusion criteria. Of these, complications occurred in 1971 (10.2%) cases. Overall complication rates differed significantly among idiopathic, congenital, and neuromuscular cases (P < 0.001). Neuromuscular scoliosis had the highest rate of complications (17.9%), followed by congenital scoliosis (10.6%) and idiopathic scoliosis (6.3%). Rates of neurologic deficit also differed significantly based on the etiology of scoliosis (P < 0.001), with the highest rate among congenital cases (2.0%), followed by neuromuscular types (1.1%) and idiopathic scoliosis (0.8%). Neur-omuscular scoliosis and congenital scoliosis had the highest rates of mortality (0.3% each), followed by idiopathic scoliosis (0.02%). Higher rates of new neurologic deficits were associated with revision procedures (P < 0.001) and with the use of corrective osteotomies (P < 0.001). The rates of new neurologic deficit were significantly higher for procedures using anterior screw-only constructs (2.0%) or wire-only constructs (1.7%), compared with pedicle screw-only constructs (0.7%) (P < 0.001). Conclusion. In this review of a large multicenter database of surgically treated pediatric scoliosis, neuromuscular scoliosis had the highest morbidity, but relatively high complication rates occurred in all groups. These data may be useful for preoperative counseling and surgical decision-making in the treatment of pediatric scoliosis.

Rates of new neurological deficit associated with spine surgery based on 108,419 procedures: A report of the scoliosis research society morbidity and mortality committee

Study Design. Retrospective review of a prospectively collected, multicenter database. Objective. To assess rates of new neurologic deficit (NND) associated with spine surgery. Summary of Background Data. NND is a potential complication of spine surgery, but previously reported rates are often limited by small sample size and single-surgeon experiences. Methods. The Scoliosis Research Society morbidity and mortality database was queried for spinal surgery cases complicated by NND from 2004 to 2007, including nerve root deficit (NRD), cauda equina deficit (CED), and spinal cord deficit (SCD). Use of neuromonitoring was assessed. Recovery was stratified as complete, partial, or none. Rates of NND were stratified based on diagnosis, age (pediatric < 21; adult ≥ 21), and surgical parameters. Results. Of the 108,419 cases reported, NND was documented for 1064 (1.0%), including 662 NRDs, 74 CEDs, and 293 SCDs (deficit not specified for 35 cases). Rates of NND were calculated on the basis of diagnosis. Revision cases had a 41% higher rate of NND (1.25%) compared with primary cases (0.89%; P < 0.001). Pediatric cases had a 59% higher rate of NND (1.32%) compared with adult cases (0.83%; P < 0.001). The rate of NND for cases with implants was more than twice that for cases without implants (1.15% vs. 0.52%, P < 0.001). Neuromonitoring was used for 65% of cases, and for cases with new NRD, CED, and SCD, changes in neuromonitoring were reported in 11%, 8%, and 40%, respectively. The respective percentages of no recovery, partial, and complete recovery for NRD were 4.7%, 46.8%, and 47.1%, respectively; for CED were 9.6%, 45.2%, and 45.2%, respectively; and for SCD were 10.6%, 43%, and 45.7%, respectively. Conclusion. Our data demonstrate that, even among skilled spinal deformity surgeons, new neurologic deficits are inherent potential complications of spine surgery. These data provide general benchmark rates for NND with spine surgery as a basis for patient counseling and for ongoing efforts to improve safety of care.

Scoliosis research society morbidity and mortality of adult scoliosis surgery

Study Design. A retrospective review. Objective. To obtain an assessment of complication incidence using the largest known database of adult scoliosis and to determine whether the rate of complication depends on various clinical parameters. Summary of Background Data. The Scoliosis Research Society (SRS) morbidity and mortality database has previously been used to assess complication rates in adolescents undergoing scoliosis correction. To better understand complications in adults, degenerative and idiopathic adult scoliosis (AS) cases were studied. Methods. The SRS morbidity and mortality database was queried to identify cases of AS from 2004 to 2007. Complications were identified and analyzed on the basis of patient type of scoliosis (degenerative vs. adult idiopathic), age, use of osteotomy, revision surgery status, and surgical approach. Age was stratified into less than or equal to 60 and greater than 60. Surgical approach was stratified into anterior only, posterior only, and combined anterior/posterior. Results. A total of 4980 cases of AS were submitted from 2004 to 2007. There were 521 patients with complications (10.5%), and a total of 669 complications (13.4%). The most common complications were dural tear 142 (2.9%), superficial wound infection 46 (0.9%), deep wound infection 73 (1.5%), implant complication 80 (1.6%), acute neurological deficits 49 (1.0%), delayed neurological deficits 41 (0.5%), epidural hematoma 12 (0.2%), wound hematoma 22 (0.4%), pulmonary embolus 12 (0.2%), and deep venous thrombosis 9 (0.2%). There were 17 deaths (0.3%). There were 2555 patients with degenerative and 2425 patients with adult idiopathic scoliosis. Complication rates in these two groups were not significantly different (11.0% and 9.9%, respectively, P = 0.20). Age was not associated with complication rate (P = 0.32). Significantly higher complication rates were identified in osteotomies, revision surgery, and/or combined anterior-posterior surgery (P = 0.0006, 0.006, and 0.03, respectively). Conclusions. The overall complication rate for AS treatment is 13.4%. Complication rate is significantly higher when osteotomies, revision procedures, and combined anterior/posterior approaches are used. Complication rate is not influenced by scoliosis type or age.

Can c7 plumbline and gravity line predict health related quality of life in adult scoliosis

Study Design. This study prospectively evaluated the health related quality of life (HRQOL) of 73 adults presenting with scoliosis at a single institution, as related to their spinal (C7 plumbline) and global (gravity line) balance. Objective. To assess the influence of sagittal and coronal balance on HRQOL in adult scoliosis. Summary of Background Data. Many surgeons believe that achieving adequate spinal balance is important in the management of adult spinal deformity, but the evidence supporting this concept remains limited. A previous study has found weak correlations between sagittal spinal balance and HRQOL in adult spinal deformity, but this finding has never been confirmed independently. In addition, although the use of the gravity line is gaining interest in the evaluation of global balance, it remains unknown if this parameter is associated with HRQOL. Methods. During a 1-year period, 73 consecutive new patients presenting with unoperated adult scoliosis and requiring full spine standing radiographs were evaluated using a force plate in order to simultaneously assess the gravity line. All patients also completed the Oswestry Disability Index (ODI) questionnaire to assess the HRQOL. Spinal balance was evaluated from the C7 plumbline and global balance from the gravity line, respectively. C7 plumbline and gravity line were both assessed with respect to the posterosuperior corner of the S1 vertebral body and central sacral vertebral line in the sagittal and coronal plane, respectively. C7 plumbline and gravity line, as well as their relative position, were correlated with the ODI, using Spearman coefficients. Results. Sagittal spinal (C7 plumbline) and global (gravity line) balance, as well as their relative position were significantly related to the ODI. A poor ODI (>34) was associated with a sagittal C7 plumbline greater than 6 cm, a sagittal gravity line greater than 6 cm, and a C7 plumbline in front of the gravity line. Correlations between coronal balance and the ODI were not statistically significant. Conclusion. Sagittal spinal and global balance was strongly related to the ODI in adults with scoliosis. The observed correlation coefficients were higher than those reported in the only previous study suggesting the detrimental association of positive sagittal balance on ODI in adult spinal deformity. Coronal spinal and global balance did not influence the ODI in the current study cohort. Thisstudy underlines the relevance of C7 plumbline and gravity line in the evaluation of spinal and global balance, and lends further support to the philosophy of achieving adequate sagittal balance in the management of adult spinal deformity, especially in patients older than 50 years old with degenerative scoliosis.

Short-term morbidity and mortality associated with correction of thoracolumbar fixed sagittal plane deformity: a report from the Scoliosis Research Society Morbidity and Mortality Committee.

Study Design. Retrospective review. Objective. Our objective was to assess the short-term complication rate in patients undergoing treatment of thoracolumbar fixed sagittal plane deformity (FSPD). Summary of Background Data. The reported morbidity and mortality for the surgical treatment of thoracolumbar FSPD is varied and based on studies with small sample sizes. Further studies are needed to better assess FSPD complication rate, and the factors that influence it. Methods. The Scoliosis Research Society (SRS) Morbidity and Mortality Database was queried to identify cases of thoracolumbar FSPD from 2004 to 2007. Complications were analyzed based on correction technique, surgical approach, surgeon experience (SRS membership status used as a surrogate), patient age, and history of prior surgery. Results. Five hundred and seventy-eight cases of FSPD were identified. Osteotomies were performed in 402 cases (70%), including 215 pedicle subtraction osteotomies (PSO), 135 Smith–Petersen osteotomies (SPO), 19 anterior discectomy with corpectomy procedures (ADC), 18 vertebral column resections (VCR), and 15 unspecified osteotomies. There were 170 complications (29.4%) in 132 patients. There were three deaths (0.5%). The most common complications were durotomy (5.9%), wound infection (3.8%), new neurologic deficit (3.8%), implant failure (1.7%), wound hematoma (1.6%), epidural hematoma (1.4%), and pulmonary embolism (1.0%). Procedures including an osteotomy had a higher complication rate (34.8%) than cases not including an osteotomy (17.0%, P < 0.001), and this remained significant after adjusting for the effects of patient age, surgeon experience, and history of prior surgery (P = 0.003, odds ratio = 2.070, 95% CI = 1.291–3.321). Not significantly associated with complication rate were patient age (P = 0.68), surgeon experience (P = 0.18), and history of prior surgery (P = 0.10). Complication rates were progressively higher from no osteotomy (17.0%), to SPO (28.1%), to PSO (39.1%), to VCR (61.1%). Conclusion. The short-term complication rate for treatment of FSPD is 29.4%. The complication rate was significantly higher in patients undergoing osteotomies, and more aggressive osteotomies were associated with progressively higher complication rates.

Complications in long fusions to the sacrum for adult scoliosis: minimum five-year analysis of fifty patients.

Study Design. A retrospective study of complications with minimal 5-year follow-up of 50 adults with scoliosis with fusion from T10 or higher to S1. Objectives. To document the perioperative and long-term complications and instrumentation problems, and to attempt to determine variables which may influence these problems. It is not a study of curve correction, balance, or functional outcome. Summary of Background Data. Several previous studies from this and other centers have shown a relatively high complication rate for this select group of patients. Various fusion techniques (anterior, posterior, autograft, allograft), various instrumentation techniques, and various immobilization techniques have created confusion as to the best methodology to employ. Minimal 2-year follow-ups have been standard, but longer follow-ups have shown additional problems. Methods. The study cohort consisted of 50 adult patients from a single center who had undergone corrective scoliosis surgery from T10 or higher to the sacrum and who had at least a 5-year minimum follow-up. The mean age was 54 years (range, 18–72), and the mean follow-up was 9.7 years (range, 5–26). All radiographs, office charts, and hospital charts were combed by an independent investigator for complications, which were divided into major and minor, as well as early, intermediate and late. The curvature values and corrections were the subject of a different article, and were not included in this study. Results. There were no deaths or spinal cord injuries. Six patients had nerve root complications, 4 of which totally recovered. Pseudarthrosis was seen in 24% of the patients, only 25% of which were detected within the 2-year follow-up period. Pseudarthrosis was most common at the lumbosacral level. There was no statistical difference in the pseudarthrosis rate between patients with sacral-only fixation versus iliac fixation. Painful implants requiring removal were noted in 11 of the 50 patients. Conclusion. Long fusions to the sacrum in adults with scoliosis continue to have a high complication rate. As compared to the original publications in the 1980s (Kostuik and Hall, Spine 1983;8:489–500; Balderston et al, Spine 1986;11:824–9) the more recent articles have shown a reduction, but not elimination of the pseudarthrosis problem using segmental instrumentation and anterior fusion of the lumbar spine coupled with structural interbody grafting at L4–L5 and L5–S1. Two-year follow-up is inadequate as pseudarthrosis and painful implants often are detected later. Only 3 of the 12 patients with pseudarthrosis were detected within the first 2 years after surgery.

Complication rates of three common spine procedures and rates of thromboembolism following spine surgery based on 108,419 procedures: A report from the scoliosis research society morbidity and mortality committee

Study Design. Retrospective review of a prospectively collected database. Objective. The Scoliosis Research Society (SRS) collects morbidity and mortality (M and M) data from its members. Our objectives were to assess complication rates for 3 common spine procedures, compare these results with prior literature as a means of validating the database, and to assess rates of pulmonary embolism (PE) and deep venous thrombosis (DVT) in all cases reported to the SRS over 4 years. Summary of Background Data. Few modern series document complication rates of spinal surgery as routinely practiced across academic and community settings. Those available are typically based on relatively low numbers of procedures or confined to single-surgeon experiences. Methods. The SRS M and M database was queried for lumbar microdiscectomy (LD), anterior cervical discectomy and fusion (ACDF), and lumbar stenosis decompression (LSD) cases from 2004 to 2007. Revisions were excluded. The database was also queried for occurrence of clinically evident PE and DVT in all cases from 2004 to 2007. Results. A total of 9692 LDs, 6735 ACDFs, and 10,329 LSDs were identified, with overall complication rates of 3.6%, 2.4%, and 7.0%, respectively. These rates are comparable to previously published smaller series. For assessment of PE and DVT, 108,419 cases were identified and rates were calculated per 1000 cases based on diagnosis, age group, and implant use. Overall rates of PE, death due to PE, and DVT were 1.38, 0.34, and 1.18, respectively. Among 82,082 adults, the rate of PE ranged from 0.47 for LD to 12.4 for metastatic tumor. Similar variations were noted for DVT and deaths due to PE. Conclusion. Overall major complication rates for LD, ACDF, and LSD based on the SRS M and M database are comparable to those in previously reported smaller series, supporting the validity of this database for study of other less common spinal disorders. In addition, our data provide general benchmarks of clinically evident PE and DVT rates as a basis for ongoing efforts to improve care.