Survivorship analysis of Cotrel-Dubousset instrumentation in idiopathic scoliosis

Long-term reoperation rates following spinal fusion for neuromuscular scoliosis in nonambulatory patients with cerebral palsy

PURPOSE

To describe the incidence of reoperation and factors contributing to surgical revision within a minimum of 10 years after spinal fusion for scoliosis in patients with nonambulatory cerebral palsy (CP).

METHODS

We conducted a retrospective review of consecutive nonambulatory patients with CP who underwent primary spinal fusion at a single specialty care center with a minimum of 10 years from their index surgery (surgery dates 2001-2011). Causes of reoperation were classified as implant failure/pseudoarthrosis, surgical site infection (SSI), proximal junctional kyphosis, prominent/symptomatic implants, and implant removal. Reoperation rates with 95% confidence intervals were calculated for each time interval, and an actuarial survival curve was generated.

RESULTS

144 patients met inclusion criteria (mean age = 14.3 ± 2.6 years, 62.5% male); 85.4% had 5 years follow-up data; and 66.0% had 10 years follow-up data. Estimates from the actuarial analysis suggest that 14.9% (95% CI: 10.0-22.0) underwent reoperation by 5 years postsurgery, and 21.7% (95% CI: 15.4-30.1) underwent reoperation by 10 years postsurgery. The most common causes for reoperation were implant failure/pseudoarthrosis, SSI, and prominent/symptomatic implants.

CONCLUSIONS

To our knowledge, this study is the largest long-term follow-up of nonambulatory patients with CP and neuromuscular scoliosis who underwent spinal fusion. Approximately 22% of these patients required reoperation 10 years after their index surgery, primarily due to implant failure/pseudoarthrosis, SSI, and prominent/symptomatic implants. Complications and reoperations continued throughout the 10 years period after index surgery, reinforcing the need for long-term follow-up as these patients transition into adulthood.

LEVEL OF EVIDENCE

III.

Biomedical Applications of Titanium Alloys: A Comprehensive Review

Titanium alloys have emerged as the most successful metallic material to ever be applied in the field of biomedical engineering. This comprehensive review covers the history of titanium in medicine, the properties of titanium and its alloys, the production technologies used to produce biomedical implants, and the most common uses for titanium and its alloys, ranging from orthopedic implants to dental prosthetics and cardiovascular devices. At the core of this success lies the combination of machinability, mechanical strength, biocompatibility, and corrosion resistance. This unique combination of useful traits has positioned titanium alloys as an indispensable material for biomedical engineering applications, enabling safer, more durable, and more efficient treatments for patients affected by various kinds of pathologies. This review takes an in-depth journey into the inherent properties that define titanium alloys and which of them are advantageous for biomedical use. It explores their production techniques and the fabrication methodologies that are utilized to machine them into their final shape. The biomedical applications of titanium alloys are then categorized and described in detail, focusing on which specific advantages titanium alloys are present when compared to other materials. This review not only captures the current state of the art, but also explores the future possibilities and limitations of titanium alloys applied in the biomedical field.

Long-term Outcomes of Posterior Multilevel Crack Osteotomy: Revisional Surgery for Scoliosis With a Fusion Mass

OBJECTIVE

Osteotomies are required for the mobilization of spinal segments in patients with revisional scoliosis surgery with a fusion mass; however, only a few techniques have shown efficacy and safety, and their mid- and long-term outcomes remain unelucidated. This study aimed to analyze long-term outcomes of the posterior multilevel crack osteotomy (PMCO) technique for revisional surgery for scoliosis with a fusion mass.

METHODS

Data from 18 patients who underwent revisional scoliosis surgery using PMCO between 2009 and 2015 and had more than 5-year follow-up were retrospectively reviewed. The Cobb angle and coronal and sagittal balance parameters were examined preoperatively, postoperatively, and during the final follow-up. Perioperative parameters and complications were also assessed.

RESULTS

Preoperative and postoperative Cobb angles were 60.5° and 29.9°, respectively (p < 0.001); this improvement was maintained until the final follow-up (33.4°, p = 0.058). The difference in preoperative and postoperative coronal balance was statistically significant (15.9 mm and 9.2 mm, respectively; p < 0.001); this was maintained until the final follow-up (p = 0.071). There was no change in sagittal balance parameters over the 3 measurement periods. Only 1 patient showed PMCO-related motor weakness, but he spontaneously recovered 3 months after postsurgery. Pseudarthrosis was not observed during the follow-up period.

CONCLUSION

Incomplete osteotomy using PMCO provided satisfactory deformity correction without severe complications during revisional surgery for scoliosis with a fusion mass. It may be a less invasive procedure that maintains cortical continuity, preserves soft tissues, and provides sufficient mobility for the correction of spinal segments.

Efficiency of repeated corrective surgery in patients with spinal deformities: analysis of the immediate results of a monocenter cohort and a brief review of the literature

Objective. To analyze the results of repeated corrective surgery in patients with spinal deformities of various etiologies.

Material and Methods. The study group included 87 patients (mean age is 22.8 years, m : f = 10 : 77) who underwent repeated deformity correction using third-generation instrumentation (CDI and its analogues), and were selected from 144 patients previously operated on for spinal deformities of various etiologies using different types of spinal instrumentation. The magnitude of scoliotic deformity, thoracic kyphosis, lumbar lordosis, rotation of the apical vertebra, the volume of intraoperative blood loss, and the duration of the operation were assessed. All patients answered the questions of the SRS-24 questionnaire at the stages of treatment and postoperative follow-up, and were also examined by computer optical topography method.

Results. Out of 87 reoperated patients, 74 had idiopathic scoliosis. In 31 patients, the results were evaluated within a period of at least 2 years (average 61.8 months). As a result of the intervention, the primary curve was corrected by 29.1° (36.5 %). Loss of correction was 4.6° (p < 0.001), derotation of the apical vertebra – from 34.9° to 22.1° (p < 0.001) and loss of correction – 0.8°. The average blood loss varied from 810 to 1138 ml, and the operation time – from 187 to 289 min. Computer optical topography data convincingly confirmed the corrective effect achieved during the repeated intervention. According to the questionnaire (SRS-24), satisfaction with the results of the operation was quite high.

Conclusion. Repeated corrective interventions in patients with spinal deformities of various etiologies, even in long-term periods, can partially restore the lost primary correction and improve the quality of life of patients, which is confirmed by clinical and radiographic data, the results of computer optical topography and the SRS-24 questionnaire.

Indications and timing of revision spine surgery in adults after adolescent surgery for idiopathic scoliosis

STUDY DESIGN

Retrospective case series.

PURPOSE

To characterize the indications and timing of revision spine surgery in adulthood after adolescent surgery for idiopathic scoliosis. Previous studies have shown that revision usually occurs within 3 months or more than 5 years after the index operation. It is not clear what the indications for and timeline to revision surgery are in these patients during adulthood.

METHODS

421 patients with idiopathic scoliosis were seen as adults over a 15-year period. 81 patients who had scoliosis surgery prior to age 18 were identified. This cohort was studied for indications and time from index to revision operation. Their clinical presentation and a description of their revision operation was also documented.

RESULTS

Of the 81 patients, 18 (22.2%) had a revision surgery as an adult. Indications for revision in order of prevalence were implant malposition, subjacent segment degeneration and stenosis, pseudoarthrosis, delayed deep wound infection, spondylolisthesis, and symptomatic implants. Revisions were indicated generally within 15 years or more than 30 years after the initial operation.

CONCLUSIONS

The timeline for revision spine surgery in idiopathic scoliosis was bimodal, with revisions occurring within 15 years or over 30 years after the initial operation. Implant malposition and subjacent segment degeneration were the most prevalent indications for adulthood revision.

LEVEL OF EVIDENCE

Prognostic-IV.

Very long-term clinical and radiographic outcomes after posterior spinal fusion with pedicular screws for thoracic adolescent idiopathic scoliosis

PURPOSE

To report radiographic and functional outcomes, with an average follow-up of 20 years, of adolescents treated surgically for thoracic idiopathic scoliosis by hybrid construct using only pedicular screws for the distal fixation.

METHODS

We retrospectively reviewed 109 patients. Radiographic data were evaluated on fullspine radiographs (Cobb angle, pelvic incidence, sacral slope, pelvic tilt, thoracic kyphosis, lumbar lordosis). Clinical data were evaluated with ODI, SF-12, SRS-30 and Analog Pain Scale. Disc height and listhesis below the arthrodesis were measured.

RESULTS

We analyzed 90 women and 19 men with a mean age of 16.9 y.o. at surgery. Radiographic data were assessed for 46 patients after 17.4 years. Mean preoperative Cobb angle was 58°, mean correction 40.1% with 5.3° of loss at final FU. Lumbar lordosis and thoracic kyphosis increased significantly at last FU. Degenerative changes below the arthrodesis were reported in 5 cases. Clinical data were assessed for 42 patients after 19.9 years: SRS-30 3.8; ODI 12.3%; SF-12 PCS 48.6 and MCS 46. Low back pain was reported in 69% of cases with low intensity (3.1). The lowest instrumented vertebrae did not influence significantly the functional outcome.

CONCLUSIONS

The correction of thoracic AIS with lumbar or thoracolumbar pedicle screw instrumentation provides good radiological and clinical outcomes at very long term. The reduction in the coronal plane is stable; the HRQoL is quite as good as the general population. The degenerative evolution below remain relatively rare, therefore global sagittal balance is not modified.

Health-related quality of life, including marital and reproductive status, of middle-aged Japanese women with posterior spinal fusion using Cotrel-Dubousset instrumentation for adolescent idiopathic scoliosis: Longer than 22-year follow-up

BACKGROUND

Few studies have examined long-term outcomes after posterior spinal fusion using Cotrel-Dubousset instrumentation (CDI) for adolescent idiopathic scoliosis (AIS). Most patients with AIS are female, and their main concern is how spinal fusion will affect their future life. This study aimed to investigate the long-term health-related quality of life (HRQOL), including marital and reproductive status, of middle-aged Japanese women who underwent posterior spinal fusion using CDI for AIS in its earliest days in Japan.

METHODS

Japanese women who were younger than 20 years of age at the time of surgery using CDI, between 1985 and 1995, were targeted. Roland-Morris Disability Questionnaire, Oswestry Disability Index, Scoliosis Research Society-22 questionnaire, and 36-Item Short-Form Survey (SF-36) were used to evaluate HRQOL. Marital and reproductive status were also investigated. These results were compared to those of healthy women controls and Japanese national data for 2015.

RESULTS

Of 87 female patients, 29 (33.3%) were included, with 71 healthy women as controls. The average age of the patient group was 42.7 years (range 37-48 years), and the average follow-up period was 27.5 years (range 22-32 years). HRQOL scores in the patient group were generally lower than that in the healthy control group, although there was no significant difference between the two groups in the role component summary score (RCS) of SF-36. Marital and reproductive status were not significantly different between patient and control groups, and results for the patient group were similar to Japanese national data.

CONCLUSIONS

This is the first study of HRQOL in middle-aged patients who underwent posterior spinal fusion using CDI for AIS in Japan. Although HRQOL scores expect RCS of the patient group were lower than those of the healthy control group, the effects of posterior spinal fusion using CDI on women's social life and marital and reproductive statuses were minimal.

Impact of Electrocautery on Fatigue Life of Spinal Fusion Constructs-An In Vitro Biomechanical Study

Instrumentation failure in the context of spine surgery is attributed to cyclic loading leading to formation of fatigue cracks, which later propagate and result in rod fracture. A biomechanical analysis of the potential impact of electrocautery on the fatigue life of spinal implants has not been previously performed. The aim of this study was to assess the fatigue life of titanium (Ti) and cobalt-chrome (CoCr) rod-screw constructs after being treated with electrocautery. Twelve spinal constructs with CoCr and Ti rods were examined. Specimens were divided into four groups by rod material (Ti and CoCr) and application of monopolar electrocautery on the rods’ surface (control-group and electrocautery-group). Electrocautery was applied on each rod at three locations, then constructs were cyclically tested. Outcome measures were load-to-failure, total number of cycles-to-failure, and location of rod failure. Ti-rods treated with electrocautery demonstrated a significantly decreased fatigue life compared to non-treated Ti-rods. Intergroup comparison of cycles-to-failure revealed a significant mean decrease of almost 9 × 10⁵ cycles (p = 0.03). No CoCr-rods failed in this experiment. Electrocautery application on the surface of Ti-rods significantly reduces their fatigue life. Surgeons should exercise caution when using electrocautery in the vicinity of Ti-rods to mitigate the risk of rod failure.

Incidence of complete spinal instrumentation removal following surgery for spinal deformity: a 22-year single institution study

The aim of this study was to define the incidence of complete implant removal following surgical correction of spinal deformity in pediatric patients over a 22-year period and identify possible risk factors. A retrospective review of our Pediatric Orthopedic Spine Database between 1992 and 2016 was performed. We included patients undergoing complete implant removal following scoliosis correction surgery with a minimum of 2-year follow-up. Medical charts were reviewed to determine initial patient diagnosis and the indication for implant removal. Statistical analysis was carried out to determine the associations between sex and factors such as primary diagnosis and indication for removal. A review of 1117 procedures in 1114 patients identified complete instrument removal in 52 (4.7%) patients (34 females and 18 males). Mean time to removal following surgery was 2.3 years (range: 0-5.9 years). Removal occurred in 24 of 548 (4.4%) patients with adolescent idiopathic scoliosis, four of 117 (3.4%) patients with juvenile idiopathic scoliosis, 11 of 287 (3.8%) patients with neuromuscular scoliosis, and three of 79 (3.8%) patients with syndromic scoliosis. Infection was the most common indication for complete implant removal [24 (46%) patients], followed by persistent pain [8 (15%) patients], and metal intolerance [8 (15%) patients]. There were two cases of early infection (<1 year following surgery) and 22 late infections (≥1 year following surgery). The overall 22-year incidence of complete implant removal following spinal correction surgery for scoliosis was 4.7%. Infection continues to be the most common indication, followed by pain and metal intolerance.

Secondary Surgery Rates After Primary Fusion for Adolescent Idiopathic Scoliosis

Instrumented spinal fusion is the gold standard treatment for surgical magnitude adolescent idiopathic scoliosis (AIS), with the goal being stable fusion without the need for additional procedures. The purpose of this study was to define the surgical return rates of AIS at a single center with respect to various instrumentation constructs used during initial spinal fusion. A retrospective chart review was performed of all patients with AIS who underwent instrumented fusion with a minimum of 2-year follow-up. Demographic information, implant type, and surgical approach for the primary surgery and all subsequent secondary operations were recorded. Four hundred eleven patients who underwent instrumented fusion for AIS during the study period met inclusion criteria. Sixty-six secondary operations were performed in 50 patients (12.2%). Symptomatic hardware, pseudarthrosis, and infection were the most common indications for secondary surgery. Posterior pedicle screw constructs had a lower secondary surgery rate (5.8%) compared with hybrid and combined fusions (P<.05). The all hook, hybrid, anterior only, and combined fusions had secondary surgery rates of 13.0%, 18.5%, 10.0%, and 20.8%, respectively, which were not statistically different. When specifically comparing pedicle screw with hook constructs, there was a statistically lower pseudarthrosis rate (P=.03) favoring pedicle screw instrumentation. Patients undergoing instrumented fusion for AIS are at some risk for subsequent surgery. To lessen that risk, pedicle screw constructs should be considered, as they have shown an overall lower secondary surgery rate and in particular a lower rate of pseudarthrosis. [Orthopedics. 2019; 42(4):235-239.].

Preliminary experience with SpineEOS, a new software for 3D planning in AIS surgery

PURPOSE

Preoperative planning of scoliosis surgery is essential in the effective treatment of spine pathology. Thus, precontoured rods have been recently developed to avoid iatrogenic sagittal misalignment and rod breakage. Some specific issues exist in adolescent idiopathic scoliosis (AIS), such as a less distal lower instrumented level, a great variability in the location of inflection point (transition from lumbar lordosis to thoracic kyphosis), and sagittal correction is limited by both bone-implant interface. Since 2007, stereoradiographic imaging system is used and allows for 3D reconstructions. Therefore, a software was developed to perform preoperative 3D surgical planning and to provide rod's shape and length. The goal of this preliminary study was to assess the feasibility, reliability, and the clinical relevance of this new software.

METHODS

Retrospective study on 47 AIS patients operated with the same surgical technique: posteromedial translation through posterior approach with lumbar screws and thoracic sublaminar bands. Pre- and postoperatively, 3D reconstructions were performed on stereoradiographic images (EOS system, Paris, France) and compared. Then, the software was used to plan the surgical correction and determine rod's shape and length. Simulated spine and rods were compared to postoperative real 3D reconstructions. 3D reconstructions and planning were performed by an independent observer.

RESULTS

3D simulations were performed on the 47 patients. No difference was found between the simulated model and the postoperative 3D reconstructions in terms of sagittal parameters. Postoperatively, 21% of LL were not within reference values. Postoperative SVA was 20 mm anterior in 2/3 of the cases. Postoperative rods were significantly longer than precontoured rods planned with the software (mean 10 mm). Inflection points were different on the rods used and the planned rods (2.3 levels on average).

CONCLUSION

In this preliminary study, the software based on 3D stereoradiography low-dose system used to plan AIS surgery seems reliable for preoperative planning and precontoured rods. It is an interesting tool to improve surgeons' practice, since 3D planning is expected to reduce complications such as iatrogenic malalignment and to help for a better understanding of the complications, choosing the location of the transitional vertebra. However, further work is needed to improve thoracic kyphosis planning. These slides can be retrieved under Electronic Supplementary Material.

Preventing Distal Junctional Kyphosis by Applying the Stable Sagittal Vertebra Concept to Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis

STUDY DESIGN

Multicenter retrospective review.

OBJECTIVE

To assess the effectiveness of using the stable sagittal vertebra (SSV) for selecting the lowest instrumented vertebrae (LIV) to prevent distal junctional kyphosis (DJK) in selective thoracic fusions.

SUMMARY OF BACKGROUND DATA

Cho et al. reported that including the SSV in a fusion decreased the rate of DJK in thoracic hyperkyphosis.

METHODS

A retrospective review was performed of patients from two pediatric hospitals with adolescent idiopathic scoliosis who underwent selective posterior thoracic fusion with the LIV at L2 or above from 2000 to 2012. Patients with less than 2 years' follow-up were excluded. The primary outcome measure was DJK, defined radiographically as ≥10° between the superior end plate of the LIV and the inferior end plate of the vertebra below on a standing lateral radiograph. We investigated the SSV, which was defined as the vertebral level at which 50% of the vertebral body was in front of the posterior sacral vertical line (PSVL) on a standing lateral radiograph. This particular definition was referred to as SSV.

RESULTS

A total of 113 patients met the inclusion criteria. Mean age was 14.4 years. Mean Cobb angle was 58°. The overall rate of DJK was 7% (8/113). When the LIV was superior to SSV, the rate of DJK was 17% (8/46) versus 0% (0/67) when the LIV was at or inferior to SSV (p=.01). The rates of DJK for patients with the LIV one, two, and three levels above SSV were 17% (4/24), 7% (1/14), and 43% (3/7), respectively. There was no significant association between preoperative or postoperative maximum kyphosis, thoracic kyphosis, thoracolumbar kyphosis, pelvic incidence, sagittal balance or coronal balance, and development of DJK.

CONCLUSION

Although LIV selection is complex, choosing the LIV at or below the SSV is a simple rule that minimizes the risk of DJK.

LEVEL OF EVIDENCE

Level IV.

The Fate of Patients with Adult Spinal Deformity Incurring Rod Fracture After Thoracolumbar Fusion

OBJECTIVE

To report the outcome of adult spinal deformity (ASD) in patients with rod fracture (RF) after thoracolumbar fusion.

METHODS

Retrospective review of prospective, multicenter database. Operative patients with ASD ≥18 years old with RF after ASD surgery and with a minimum 6-month follow-up after RF were included. Health-related quality of life scores and radiographic alignment were compared with nonparametric paired and independent testing (P < 0.05).

RESULTS

A total of 51 of 343 patients with ASD (14.9%) sustained a RF, of whom 44 (86.3%) had at least 6-month follow up after RF (mean age = 61.2 years, mean body mass index = 29.6 kg/m²). Mean total follow-up was 37.8 months (range 24.5-66.7 months). Interbody fusion was used in 26 cases of RF (59.1%) (transforaminal lumbar interbody fusion, n = 17 [65.4%], anterior lumbar interbody fusion, n = 5 [19.2%]). RF was symptomatic in 26 of 44 (59.1%) of patients and discovered incidentally in 18 of 44 patients (40.9%). Overall, 28 RFs were revised (63.6%); 12 of 23 (52.2%) unilateral RF and 16 of 21 (76.2%) bilateral RF at last follow-up. Revision patients were significantly more likely to be symptomatic at the time of RF detection (78.6% vs. 25.0%, P = 0.0006), and had significantly worse Oswestry Disability Index and Scoliosis Research Society-22r pain scores.

CONCLUSIONS

RFs were detected in 14.9% of patients with ASD and were most common at the L4-L5 and L5-S1 levels. Approximately 63.6% of patients underwent revision surgery. The decision to perform revision surgery may be based predominantly on symptoms referable to the RF, pain, and perceived disability, as radiographic parameters at the time of RF did not differ significantly between patients who did and did not undergo revision.

5-Year Reoperation Risk and Causes for Revision After Idiopathic Scoliosis Surgery

STUDY DESIGN

An actuarial "survivorship" analysis.

OBJECTIVE

The aim of this study was to define the incidence and cause of surgical revision 5 years after scoliosis surgery.

SUMMARY OF BACKGROUND DATA

Data on contemporary revision surgery rates after idiopathic scoliosis surgery beyond the 2 years postoperatively in the adolescent and young adult population are limited.

METHODS

Patients enrolled in a prospective, multicenter, idiopathic scoliosis surgical registry from 1995 to 2009 were reviewed. Any spine reoperation was defined as a "terminal event." An actuarial survivorship analysis that adjusts for patients lost to follow-up was performed to determine cumulative survival. Time intervals were defined as 0 to <3 months, 3 months to <1 year, 1 to <2 years, 2 to <5 years, and 5 to 10 years. Registry data and radiographs were reviewed and five categories for reoperation assigned: 1) implant failure and/or pseudarthrosis, 2) implant misplacement and/or prominence, 3) wound complication and/or infection, 4) residual deformity and/or progression, and 5) other.

RESULTS

One thousand four hundred thirty-five patients from 12 sites were included. The majority were female (80%), with major thoracic curves (76% Lenke 1-4), and average age of 15 ± 2 years (10-22) at surgery. Most had posterior spinal instrumentation and fusion (81%). At this time, 75 (5.2%) patients required reoperation. Twenty-two occurred within 3 months postop, 10 more before 1 year, 12 more before 2 years, another 20 by 5 years, and 10 more after 5 years. This corresponded to an actuarial cumulative survival of 98.3% at 3 months, 97.5% at 1 year, 96.6% at 2 years, 93.9% at 5 years, and 89.8% at the final interval (5-10 yrs).

CONCLUSION

Revisions for scoliosis continue to occur well after 2 years with a 5-year survivorship of 93.9%. Reasons for reoperation are not uniformly distributed over time, with implant-related issues and infection the leading cause for early revision, while late infection was the most common cause after 2 years. Long-term follow-up of these postoperative patients remains important.

LEVEL OF EVIDENCE

3.

Risk of revision surgery for adult idiopathic scoliosis: a survival analysis of 517 cases over 25 years

PURPOSE

Little is known about the long-term status of patients operated for spine deformities. The aim of this study was to determine the survival of primary fusion in adult idiopathic scoliosis and identify the risk factors of revision surgery.

METHODS

Adult patients who underwent primary fusion for idiopathic scoliosis between 1983 and 2011 were included in a continuous monocentric retrospective series. Any additional surgery was registered for survival analysis. Survival and follow-up were estimated by the Kaplan-Meier method and an analysis was performed to identify the risk factors of revision surgery.

RESULTS

This series included 447 women (86.5 %) and 70 men (13.5 %) reviewed after a mean follow-up of 7 years (range 0-26.4). Mean age was 44.4 years. Fusion was performed on a median 11 levels (range 3-15); revision rate was 13 % (CI 10-17), 18 % (CI 14-23) and 20 % (CI 16-26) at 5, 10 and 15 years, respectively. Revision surgery was associated with age, anterior release, length of fusion, the inferior limit of fusion, post-operative sagittal balance and junctional kyphosis. The length of fusion (HR 1.13 per vertebrae fused, p = 0.007) and the lower limit of fusion (HR 5.9, p < 0.001) remained independent predictors of revision surgery on multivariate analysis.

CONCLUSION

This series evaluated the risk of revision surgery following spinal fusion for idiopathic scoliosis. Our results show that the risk seemed to increase linearly with a rate of nearly 20 % after 10 years. The length and lower limit of fusion are the main risk factors for revision surgery. Level IV (e.g. case series).

Impact of Increasing Age on Outcomes of Spinal Fusion in Adult Idiopathic Scoliosis

OBJECTIVE

To investigate the role of advancing age on postoperative complications and revision surgery after fusion for scoliosis.

METHODS

A retrospective, cohort study was performed using the Thomson Reuters MarketScan database, examining patients with adult scoliosis who underwent spinal fusion from 2000 to 2009. Primary outcomes included infection, hemorrhage and pulmonary embolism (PE) within 90 days of surgery, and refusion. The effect of increasing age was estimated using the odds ratio (OR) of complications in a multivariate logistic regression analysis, and a Cox proportional hazard model estimated the hazard ratio of refusion.

RESULTS

A total of 8432 patients were included in this study. Overall, the average age was 53.3 years, with 26.90% males and 39% with a Charlson Comorbidity Score of ≥ 1. Most patients had commercial insurance (66.81%), with 26.03% and 7.16% covered by Medicare and Medicaid, respectively. Increasing age (per 5-year increment) was a significant predictor of hemorrhagic complication (OR, 1.06; confidence interval [CI], 1.01-1.11; P = 0.0196), PE (OR, 1.09; CI, 1.03-1.16; P = 0.0031), infection (OR, 1.04; CI, 1.01-1.07; P = 0.0053), and refusion (hazard ratio, 1.07; CI, 1.02-1.13; P = 0.0103).

CONCLUSIONS

In this study, age was associated with increased risk of hemorrhage, PE, infection, and refusion. With the aging population, the role of patient age on postoperative healing and outcomes deserves deeper investigation after repair of adult idiopathic scoliosis.

Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity

OBJECT

Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD.

METHODS

This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°.

RESULTS

Of 287 patients who otherwise met inclusion criteria, 200 (70%) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81% were women; 10% were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25%) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53%, stainless steel (SS), in 26%, or titanium alloy (TA) in 21% of cases; the rod diameters were 5.5 mm (in 68% of cases), 6.0 mm (in 13%), or 6.35 mm (in 19%). RF occurred in 18 cases (9.0%) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0% of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0% to 31.6% across centers. CC rods were used in 68% of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33% vs 0%, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95% CI 2.01-15.8).

CONCLUSIONS

Rod fracture occurred in 9.0% of ASD patients and in 22.0% of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.

Outcomes following removal of instrumentation after posterior spinal fusion

BACKGROUND

Although there is good evidence to support the removal of instrumentation for infection following posterior spine fusion, there are few studies that report outcomes following removal for late operative site pain. The purpose of this study was 3-fold: (1) to determine whether removal of instrumentation following posterior spinal fusion resolves preoperative pain, (2) to determine whether indolent infection not detected before removal of instrumentation is related to late operative site pain, and (3) to determine whether curve progression differs when spinal hardware is removed for infection versus late operative site pain.

METHODS

A retrospective study of consecutive patients aged 10 to 21 years, who underwent removal of instrumentation after posterior spinal fusion over a 10-year-period was conducted. Patient demographics, preoperative and postoperative imaging results, laboratory studies, and operative findings were reviewed. All patients had a minimum 2-year follow-up. Statistical analysis was performed using 2-sample t test, bivariate analysis, and multivariate logistic regression models.

RESULTS

Seventy-five patients were included. Indications for removal of spinal instrumentation were pain (57%), infection (28%), hardware failure (8%), and prominent hardware (7%). The mean time from index procedure to hardware removal was 2.8 years. The average loss of curve correction following complete hardware removal was 23.1 degrees. Patients who underwent removal of hardware because of infection had bigger changes in their curves than those without infection (mean, 33.8 degrees vs. 18.8 degrees). Of the 43 patients with pain, only 40% reported relief of their symptoms following removal of hardware. Sixteen of the 43 patients were found to have indolent infection confirmed by positive intraoperative culture results.

CONCLUSIONS

Patients should be cautioned that hardware removal after posterior spinal fusion may not provide complete pain relief. Furthermore, there is risk for curve progression following removal of instrumentation, particularly in the setting of infection. Back pain may be an indicator of infection, and intraoperative cultures should be taken at the time of implant removal.

LEVEL OF EVIDENCE

Level IV; retrospective case series.

Survivorship analysis after primary fusion for adult scoliosis. Prognostic factors for reoperation

BACKGROUND CONTEXT

Adult scoliosis surgery is a challenging procedure with high rate of complications and reoperations. Reoperation rates vary widely. Long-term survival for this surgery still remains unknown, and the prognostic factors for reoperation are not well defined.

PURPOSE

To assess adult scoliosis surgery survival (without the need of reoperation) after primary fusion in adults with mainly frontal deformity and to define prognostic factors for reoperation.

STUDY DESIGN

Survival analysis of a cohort of consecutive adult patients, primarily operated on scoliosis using segmental instrumentation (retrospective cohort study).

PATIENT SAMPLE

Fifty-nine patients older than 21 years at primary surgery (median age, 42 years), who presented idiopathic or degenerative curves with frontal Cobb >40° (median preoperative frontal Cobb 59°), more than four-level fusion, and a 2-year minimum postoperative follow-up (median, 8.5 years; 41% patients had a longer than 10-year follow-up).

OUTCOME MEASURES

Clinical and preoperative radiographic parameters were analyzed preoperatively and evaluated as prognostic factors for reoperation.

METHODS

Survival was estimated using Kaplan-Meier method. Prognostic factors (clinical and radiographic) for reoperation were evaluated. Logistic regression using backward elimination was used for multivariate analysis.

RESULTS

Survival was 89.8% at 1 year, 79.4% at 2 years, 73.4% at 3 years, 64% at 5 years, and 60.9% at 10 years. Overall, 21 patients (35.6%) underwent revision surgery. The most common reasons for reoperation were painful/prominent implants, adjacent-segment degeneration, and infection. American Society of Anesthesiologists Type II patients and double surgical approach were associated with a higher revision rate. Preoperative thoracic kyphosis was significantly higher in reoperated patients.

CONCLUSIONS

The 10-year survival rate of primary scoliosis surgery in adult patients is 61%. Risk factors identified for reoperation included patients with higher morbidity, double surgical approach, and preoperative thoracic hyperkyphosis.

Complications and outcomes of complex spine reconstructions in poliomyelitis-associated spinal deformities: a single-institution experience

STUDY DESIGN

Retrospective case series.

OBJECTIVE

To share our institutional experience with spinal reconstruction for deformity correction in patients with a history of poliomyelitis.

SUMMARY OF BACKGROUND DATA

Polio and postpolio syndrome are not uncommonly related to a paralytic spinal deformity. Limited modern data exist regarding outcomes and complications after spinal reconstruction in this population.

METHODS

A clinical database was reviewed for patients undergoing spinal reconstruction for polio-associated spinal deformity at our institution from 1985 to 2012. Relevant demographic, medical, surgical, and postoperative information were collected from medical records and analyzed. Preoperative and last follow-up Scoliosis Research Society-22 Questionnaire scores were recorded.

RESULTS

A total of 22 patients with polio who underwent surgical deformity correction were identified. Mean age was 49 years (range, 12-74 yr), and 15 patients (68%) were female. Preoperative motor deficit was present in 14 of 22 (64%) patients. All patients underwent instrumented spinal fusion (mean, 13 vertebral levels, range, 3-18). Ten (10/22, 45%) patients developed major complications, and 4 patients (4/22, 18%) developed new postoperative neurological deficits. Neurological monitoring yielded a 13% false-negative rate. At 2-year follow-up, 20 of 22 patients maintained an average coronal correction of 25° (33%, P = 0.001) and sagittal correction of 25° (34%, P = 0.003). Minimum 2-year follow-up data were available for 11 of 22 (50%) patients. At an average of 72 months of follow-up (range, 28-134 mo), the mean Scoliosis Research Society-22 Questionnaire pain subscore improved from a mean of 2.75 to 3.6 (P = 0.012); self-image from 2.8 to 3.7 (P = 0.041); function from 3.1 to 3.8 (P = 0.036); satisfaction from 2.1 to 3.9 (P = 0.08); and mental health from 3.7 to 4.5 (P = 0.115).

CONCLUSION

Spine reconstruction for poliomyelitis-associated deformity was associated with high complication rates (54%) and sometimes unreliable neurological monitoring data. Despite this, patients undergoing spine reconstructions had significantly improved outcome scores. These data may help surgeons to appropriately counsel this complicated patient population.

Massive hemothorax caused by Gelpi retractor during posterior correction surgery for adolescent idiopathic scoliosis: a case report

Background context

Gelpi retractors are used in surgery because they can reduce paravertebral muscle damage during retraction. No pleural injuries associated with their use in posterior spine surgery have been reported.

Purpose

To describe a patient who suffered a massive postoperative hemothorax caused by a Gelpi retractor used during posterior correction surgery for adolescent idiopathic scoliosis (AIS).

Study design

Case report.

Methods

A case report of a rare hemothorax complication due to a Gelpi retractor is reported. The relevant literature was reviewed.

Results

A 12-year-old girl with Lenke type 2 AIS, with curves of 60° at T2-7 and 75° at T7-L1, underwent posterior correction and fusion surgery using a segmental pedicle screw construct placed between T2 and L2. Although the patient’s vital signs were stable during and soon after the surgery, a chest x-ray taken one day later revealed a massive left hemothorax. Her hemoglobin concentration was decreased to 5.5g/dl, and SpO₂ remained as low as 92% even with oxygen administration. Thoracoscopy revealed subpleural hemorrhaging at several points in the left upper intercostal area (T3-6), and a penetration of the pleura between the left 4th and 5th ribs. Active bleeding had already stopped. The tip of the Gelpi retractor appeared to have penetrated the pleura. A chest tube was placed in the patient to treat the hemothorax.

Conclusions

A pleural injury by the Gelpi retractor was determined to be the cause of the hemothorax in this case. The patient’s prominent thoracic hump may have increased the risk of such an injury because the tip of a Gelpi retractor might easily have become stuck in the intercostal space rather than the paravertebral muscles.

Complications of surgical treatment of pediatric spinal deformities

Surgery in a child with spinal deformity is challenging. Although current orthopedic practice ensures good long-term surgical results, complications occur. Idiopathic scoliosis represents the most extensively investigated deformity of the pediatric spine. Nonidiopathic deformities of the spine are at higher risk for perioperative and long-term complications, mainly because of underlying comorbidities. A multidisciplinary treatment strategy is helpful to assure optimization of medical conditions before surgery. Awareness of complications that occur during or after spine surgery is essential to avoid a poor outcome and for future surgical decision making. This article summarizes the complications of surgical treatment of the growing spine.

Assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity

BACKGROUND

Improved understanding of rod fracture (RF) in adult spinal deformity could be valuable for implant design, surgical planning, and patient counseling.

OBJECTIVE

To evaluate symptomatic RF after posterior instrumented fusion for adult spinal deformity.

METHODS

A multicenter, retrospective review of RF in adult spinal deformity was performed. Inclusion criteria were spinal deformity, age older than 18 years, and more than 5 levels posterior instrumented fusion. Rod failures were divided into early (≤12 months) and late (>12 months).

RESULTS

Of 442 patients, 6.8% had symptomatic RF. RF rates were 8.6% for titanium alloy, 7.4% for stainless steel, and 2.7% for cobalt chromium. RF incidence after pedicle subtraction osteotomy (PSO) was 15.8%. Among patients with a PSO and RF, 89% had RF at or adjacent to the PSO. Mean time to early RF (63%) was 6.4 months (range, 2-12 months). Mean time to late RF (37%) was 31.8 months (range, 14-73 months). The majority of RFs after PSO (71%) were early (mean, 10 months). Among RF cases, mean sagittal vertical axis improved from preoperative (163 mm) to postoperative (76.9 mm) measures (P<.001); however, 16 had postoperative malalignment (sagittal vertical axis>50 mm; mean, 109 mm).

CONCLUSION

Symptomatic RF occurred in 6.8% of adult spinal deformity cases and in 15.8% of PSO patients. The rate of RF was lower with cobalt chromium than with titanium alloy or stainless steel. Early failure was most common after PSO and favored the PSO site, suggesting that RF may be caused by stress at the PSO site. Postoperative sagittal malalignment may increase the risk of RF.

Outcome of Revision Surgery in Pediatric Spine Deformity Patients

STUDY DESIGN

Retrospective case series.

OBJECTIVES

To report the complications and outcomes of pediatric revision spine surgery and review the surgical indications and treatment methods.

BACKGROUND SUMMARY

Recent reports have shown the necessity of revision spine surgery for pediatric deformities. Many reports have shown the result of revision surgery for pediatric spinal deformity.

MATERIALS AND METHODS

We conducted a retrospective review of 638 patients with pediatric spinal deformity who were treated with surgery from 1996 to 2007. We identified 50 patients who underwent revision spinal fusion surgery with a minimum of 3 years of follow-up.

RESULTS

Mean follow-up was 4 years (range, 3-8.3 years). The diagnosis at index surgery was idiopathic scoliosis in 18 patients, congenital scoliosis in 13, neuromuscular scoliosis in 13, tumor and spinal arteriovenous malformation in 4, burst fracture in thoracic spine in 1, and Scheuermann kyphosis in 1. The primary surgeries were 1 hemi epiphysiodesis, 3 anterior spinal fusions, 4 posterior decompressions, 8 combined anterior and posterior spinal fusions, and 34 posterior spinal fusions. A total of 16 patients had pseudarthrosis, 12 decompensation, 11 progressive kyphosis, 8 crankshaft phenomenon, 2 infections, and 1 junctional degeneration. All 50 reoperations included spinal instrumentation and fusion. The revision surgeries were 2 anterior spinal fusions, 14 posterior fusions, and 34 combined anterior and posterior spinal fusions. Spine arthrodesis was obtained in 98% of patients (49 of 50) and complications occurred in 14% of patients (7 of 50). The Scoliosis Research Society Patient Questionnaire outcomes at the latest follow-up were as follows: total 3.95, function 3.88, pain 3.83, self-image 3.98, and mental health 4.04.

CONCLUSION

Pseudarthrosis was the most common indication for revision surgery, and bony union was achieved in 98% with revision surgery. Despite the complications, pediatric revision spine surgery can achieve successful outcomes.

Surgery of lumbar and thoracolumbar scolioses in adults over 50. Morbidity and survival in a multicenter retrospective cohort of 180 patients with a mean follow-up of 4.5 years

INTRODUCTION

The increasing life expectancy of the population and the improvement in surgical and medical management of elderly patients mean that the indication for surgical treatment of adult lumbar and thoracolumbar scolioses has been extended. However the benefit/risk ratio of these procedures is still under debate.

MATERIALS AND METHODS

We reviewed 180 patients, mean age 63years old with a minimum follow-up of 1year in a retrospective, continuous, multicenter study. The incidence rate of complications from surgery and the factors influencing their frequency were evaluated by uni- and multivariate analysis. The risk of a second operation was studied by actuarial survival analysis.

RESULTS

After a mean follow-up of 4.5years, 79 patients (44%) presented with at least one complication, including 32% with a serious complication. The most frequent complications were mechanical. The risk factors were medical co-morbidities, the extent of fusion and the extent of the preoperative sagittal imbalance. A second operation was necessary in 25% of patients at 1year and 50% of patients at 6years of follow-up.

DISCUSSION

Studies in the literature show that functional results are better with surgical treatment than with medical treatment in the management of thoracic spine and thoracolumbar deformities in patients over 50years old. An objective assessment of this deformity and associated co-morbidity should make it possible to reduce the rate of complications for this type of surgery.

LEVEL OF EVIDENCE

Level IV.

A multidisciplinary approach improves infection rates in pediatric spine surgery

BACKGROUND

Surgical site infections (SSI) associated with elective pediatric spinal surgery are a commonly reported complication, increasing hospital length of stay, readmissions, operations, and financial costs. In July 2007, a multidisciplinary task force, designated Target Zero, was created to address this issue and establish prevention protocols at our institution.

METHODS

A consecutive series of 394 patient charts from April 2006 to September 2008 were retrospectively reviewed to identify patients who developed an SSI secondary to elective spinal surgery. Four cohorts were evaluated; high-risk (HR) and low-risk (LR) patients who underwent surgery before (April 2006 to June 2007) and after (July 2007 to September 2008) Target Zero initiation. The definition of HR included diagnoses of cerebral palsy, spina bifida, muscle disease, paralytic deformities, and vertebral column resections. Patients were followed for 1 year to meet The Center for Disease Control-National Health Safety Network's definition of an SSI with an implantable device. Overall infection rates were determined for each group and compared statistically.

RESULTS

A total of 192 patients (70 HR and 122 LR) underwent surgery before, and 202 patients (92 HR and 110 LR) underwent surgery after Target Zero initiation. Overall infection rates were reduced from 7.8% to 4.5% (P=0.203), 12.9% to 6.5% (P=0.183), and 4.9% to 2.7% (P=0.505) for all patients, HR patients, and LR patients, respectively. The relative risk reduction was 43.0% for all patients, 49.3% for HR patients, and 44.6% for LR patients.

CONCLUSIONS

Although decreases in overall infection rates were not statistically significant, the results from Target Zero were shown to be clinically meaningful with a relative risk reduction approaching 50% overall and in defined subgroups. Based on the number needed to treat analysis, 1 infection in every 16 patients within the HR group, and 1 in 30 overall, was prevented up to 1 year postoperatively. This study is the first to document the effectiveness of a multidisciplinary team implementing protocols for decreasing infection rates in pediatric spine surgery.

Cotrel-dubousset instrumentation for the correction of adolescent idiopathic scoliosis. Long-term results with an unexpected high revision rate

Background

For many years, the CD instrumentation has been regarded as the standard device for the surgical correction of adolescent idiopathic scoliosis (AIS). Nevertheless, scientific long-term results on this procedure are rare. Therefore, we conducted a retrospective follow-up study of patients treated for AIS with CD instrumentation and spondylodesis.

Methods

A total of 40 patients with AIS underwent CD instrumentation in our department within 3 years and between 1990 and 1992. For the retrospective analysis, first all the patient documents were reviewed, and pre-/postoperative X-ray images as well as those at the latest follow-up were analysed. Furthermore, it was attempted to conduct a clinical survey using the SRS-24 questionnaire, which was sent to the patients after a preceding announcement on the phone.

Results

Radiologically, the frontal main curvature was improved from a preoperative angle of 69.2° to a postoperative angle of 35.4°, and the secondary curvature was improved from a preoperative angle of 42.6° to a postoperative angle of 20.5°. The latest radiological follow-up at average 57.4 months post surgery showed an average loss of correction of 9.6° (main curvature) and 4.6° (secondary curvature), respectively.

Within the first 30 days post surgery, 3 out of 40 patients (7.5%) received early operative revision for the dislocation of hooks or rods.

At an average of 45.7 months (range 11 to 142 months), 19 out of 40 patients (47.5%; including 2 patients with early revision) received late operative revisions: The reasons were late infection (10 out of 40 patients; 25%) with the development of fistulae (7 cases) or putrid secretion (3 cases), which was resolved with the complete removal of instrumentation after all. The average time until revision was 35.5 months (range 14 to 56 months) after CD instrumentation. Furthermore, complete implant removal was necessary in 8 out of 40 patients (20%) for late operate site pain (LOSP). The average time until removal of instrumentation was 62.7 months (range 18 to 146 months) post surgery; and one patient received partial device removal for prominent instrumentation 11 months post surgery. Altogether, only 22 out of 40 CD instrumentations (55%) were still in situ.

After an average period of 14.3 years post surgery, it was possible to follow-up 14 out of 40 patients (35%) using the SRS-24 questionnaire. The average score was 93 points, without showing significant differences between patients with or without their instrumentation in situ.

Conclusions

Retrospectively, we documented for the first time a very high revisions rate in patients with AIS and treated by CD instrumentation. Nearly half of the instrumentation had to be removed due to late infection and LOSP. The reasons for the high rate of late infections with or without fistulae and for LOSP were analysed and discussed in detail.

Repeat surgical interventions following "definitive" instrumentation and fusion for idiopathic scoliosis: five-year update on a previously published cohort

STUDY DESIGN

A retrospective case series.

OBJECTIVE

To identify the overall reoperation rate and factors contributing to reoperation in a recent 5-year cohort of patients (2003-2007) undergoing spinal deformity surgery. These patients were compared with a previously published 15-year cohort of consecutive patients (1988-2002) from the same institution to assess for any significant differences in reoperation rates.

SUMMARY OF BACKGROUND DATA

In a previously published report from this institution, the reoperation rate for patients with idiopathic scoliosis treated during a 15-year period (1988-2002) was 12.9%. That group was predominantly treated with first-generation TSRH (Medtronic, Memphis, TN) implants and CD implants. Lower profile, more rigid implant systems are now used along with refined techniques for correction of scoliosis deformity. We hypothesized that these factors would lead to lower rates of reoperation. METHODS.: The medical records of 452 consecutive patients (older than 9 yr) surgically treated for idiopathic scoliosis at one institution during 5 years (2003-2007) were reviewed to identify those who required reoperation.

RESULTS

The reoperation rate for this cohort was 7.5% (34 of 452 patients). Compared with the prior cohort, significant decreases were noted with regard to total reoperation rate as well as reoperation due to infection and pseudarthrosis. Trends were noted toward decreased rates of reoperation due to prominent implants, dislodged implants, and implant proximity to vital structures. Within the newer cohort, a trend toward decreased reoperation rate was also noted for lower profile implant systems compared with first-generation TSRH implants.

CONCLUSION

With the evolution of newer lower profile segmental implant systems that provide more rigid fixation and with the advancements in techniques for deformity correction, the repeat surgical intervention rate for idiopathic scoliosis has decreased.

Unanticipated revision surgery in adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

The objective of this study was to share our experience in the surgical treatment of adolescent idiopathic scoliosis (AIS), specifically the rate of revision surgeries and their indications.

SUMMARY OF BACKGROUND DATA

Minimizing AIS surgical morbidity includes prevention of short- and long-term complications that could require an unanticipated revision. There have been an increasing number of reports about revision rates and their causes in AIS. This study summarizes the experience of a large patient population treated by a single surgeon in a single institution.

METHODS

All patients who underwent surgical treatment for AIS between 10 and 20 years of age during 1983 to 2005 were reviewed. All revision surgeries performed during the same period were searched. The indications for revision and type of procedure performed were recorded.

RESULTS

A total of 502 patients with AIS underwent spinal fusion with instrumentation at an average age of 14.3 years at initial surgery. In 485 patients, the surgery consisted of posterior-only spinal fusion. A total of 24 revision surgeries were performed for 23 patients (4.9%; cumulative probability of revision = 8%). The primary indications for revision were residual rib deformity (n = 8), instrumentation dislodgement (n = 4), compensatory curve progression (n = 3), junctional kyphosis (n = 3), and symptomatic implants (n = 3). One patient had a late infection. There was 1 case of pseudoarthrosis. One patient requested scar revision. There were no cases of neurological deficit.

CONCLUSION

In this single-surgeon series, revision after the index spinal fusion was required for a relatively low proportion of patients. The main indications for revision were residual rib deformity, hook dislodgment, and progression of the unfused compensatory curve.

Complications and risk factors of primary adult scoliosis surgery: a multicenter study of 306 patients

STUDY DESIGN

A multicentric retrospective study on primary adult scoliosis patients operated on between 2002 and 2007. A 3-step statistical analysis was performed to describe the incidence of complications, the risk factors, and the reoperation risk with survival curves for the entire cohort.

OBJECTIVE

To describe complication rate and risk factors as well as survival curves associated with adult primary scoliosis surgery in patients aged 50 years or older.

SUMMARY OF BACKGROUND DATA

Adult deformity surgery is classically associated with a high rate of complications. The identification of risk factors for developing such complications is consequently of major interest as well as survival curves that can provide useful information on reoperation risks. Although many reports exist in the literature, the cohorts analyzed are often heterogeneous and the actual prevalence of complications varies widely. This study represents to our knowledge the largest series on adult patients aged 50 years or older operated for the first time for lumbar or thoracolumbar scoliosis and excluding every other possible diagnosis.

METHODS

A retrospective review of prospectively collected data from 6 centers in France. A total of 306 primary lumbar adult or degenerative scoliosis patients older than 50 years undergoing surgery between 2002 and 2007 were included. Demographics, comorbidities, x-ray parameters, surgical data, and complications were analyzed. Statistical analysis was performed to obtain correlations and risk factors for developing complications. Reoperation risk was calculated with Kaplan-Meier survival curves.

RESULTS

A total of 306 patients aged 63 years (range, 50-83), with 83% women. Mean follow-up was 54 months. Mean Cumulative Illness Rating Scale score was 5 (range, 0-26). Main curve was 50° (range, 4-96) with apex between T12 and L2. Ten percent of patients had anterior surgery only, 18% had double anteroposterior approach, and 72% had posterior surgery only. Seventy-four percent (226 patients) had long fusions of 3 or more levels and 44% (134 patients) were fused to the sacrum. Forty percent (122 patients) had a decompression performed and 18% had an osteotomy. There were 175 complications for 119 patients (39%). No cases of death or blindness were reported. General complication rate was 13.7%, early infection occurred in 4% (12 patients), and late infection occurred in 1.2%. Neurological complications were present in 7% with 2 cases (0.6%) of late cord-level deficits and 12 reoperations (4%). Prevalence of mechanical complications was 24% (73 patients), with 58 patients (19%) needing a reoperation. Risk factors for mechanical or neurological complications were number of instrumented vertebra (P ≤ 0.01) fusion to the sacrum (P ≤ 0.001), pedicle subtraction osteotomy (PSO) (P = 0.01), and a high preoperative pelvic tilt of 26° or more (P ≤ 0.05). Kaplan-Meier survival curves showed reoperation risk of 44% at 70 months. Long fusion risk was 40% at 50 months and fusions to the sacrum reoperation risk was 48% at 49 months.

CONCLUSION

Overall complication rate was 39%, and 26% of the patients were reoperated for mechanical or neurological complications. Risk factors include number of instrumented vertebra, fusion to the sacrum, PSO, and preoperative pelvic tilt of 26° or more. There is a 44% risk of a new operation in the 6-year-period after the primary procedure.

Subsequent, unplanned spine surgery and life survival of patients operated for neuropathic spine deformity

STUDY DESIGN

Retrospective study of a prospectively assembled cohort.

OBJECTIVE

To characterize the survival from subsequent spine surgery and the life survival of patients treated surgically for severe spinal deformity due to neuropathic diseases.

SUMMARY OF BACKGROUND DATA

Survivorship analysis is widely used to study the natural history of disease processes and of treatments provided, but has very seldom been used to study patients' course after surgery for spinal deformity associated with neuropathic diseases.

METHODS

Patients with neuropathic spinal deformity treated with primary posterior instrumentation and arthrodesis from 1989 through 2002 were identified and studied by review of charts and radiographs, and by mail survey. Subsequent spine surgery and death events, and the time interval from surgery were identified. Fifteen variables possibly influencing survivorship were studied.

RESULTS

There were no perioperative deaths, spinal cord injuries, or acute wound infections in the 117 eligible patients. Reoperation and life survival statuses were available for 110 patients (94%) at an average follow-up of 11.89 years (±5.3; range: 2-20.9 yr). Twelve patients (11%) had subsequent spine surgery. Survival from subsequent spine surgery was 91% at 5 years, 90% at 10 and 15 years, and 72% at 20 years. Proximal fixation problems occurred in 4 patients. Twenty-two patients (20%) had died from 4 to 20 years postoperative. Life survival was 98% at 5 years, 89% at 10 years, 81% at 15 years, and 56% at 20 years. The only variable associated with life survival was the occurrence of one or more perioperative complications, P = 0.0032. The younger half of the series at operation (<13.75 yr) was significantly more likely to have one or more perioperative complications, P = 0.0068. Spinal deformity type and magnitude were similar for the younger and older halves of the patients. Life survival of the patients with cerebral-palsy and not-cerebral-palsy upper motor neuron disease was not different. One-hundred-two of 105 were at least satisfied or would have the surgery again for the same condition.

CONCLUSION

Survival from subsequent spine operation was similar to adolescent idiopathic scoliosis series studied in the same manner. Life survival decline began at 4 years postoperative and was significantly associated with the occurrence of one or more perioperative complications. Even after successful spine deformity surgery, this population's health status is often precarious.

Clinical and demographic characteristics of online community members--does it represent reality?

BACKGROUND

The decision to undergo surgery for scoliosis is shared between the physician, patient, and family. In an effort to obtain objective data regarding scoliosis surgery, patients often use the Internet, which includes sharing experiences in online communities. To this end, physicians have limited knowledge about disease-specific online communities.

PURPOSE

To analyze the clinical and demographic characteristics of patients who use disease-specific online communities.

STUDY DESIGN

A retrospective clinical study.

PATIENT SAMPLE

One hundred ninety-five patients with scoliosis who are also members of a popular scoliosis-specific online community.

MAIN OUTCOME MEASURES

Five domains of the Scoliosis Research Society-22 (SRS-22) quality-of-life questionnaire: function, pain, mental health, self-image, and satisfaction.

METHODS

An online questionnaire was submitted by members of a scoliosis-specific online community. One hundred ninety-five patients with scoliosis fulfilled the inclusion criteria, which represented 54% of all active members who have logged into this community during the time of data collection. A descriptive analysis was performed for demographic and clinical characteristics.

RESULTS

Analysis revealed a bimodal age distribution. Most online members were female (74%) and underwent surgical treatment (78%). Of all surgical patients, 52% had surgery between the age of 10 and 18 years. The average time since surgery (follow-up) was 10 years and 9 months. A revision rate of 17% was calculated, which increased with longer follow-up. Five of nine surgical subgroups significantly outperformed nonsurgical patients in regards of SRS-22 total scores.

CONCLUSION

This study supports that members from an online scoliosis community may be the representative sample of the general scoliosis patient population. The information obtained may be useful for physicians to understand patient concerns and mitigate treatment expectations when counseling patients.

Pediatric revision spinal deformity surgery: issues and complications

STUDY DESIGN

A review of issues and concerns associated with pediatric revision surgery.

OBJECTIVES

To describe: (1) the incidence, causes, and prevention of spine revision surgery in the pediatric population; and (2) the preoperative planning and imaging necessary for such surgeries and the associated intraoperative and technical complications (e.g., infection, blood loss, and incomplete deformity correction).

SUMMARY OF BACKGROUND DATA

Revision surgery may be needed for pediatric spinal deformity because of many factors. This article describes the assessment and performance of revision surgery to optimize results.

METHODS

The literature and the author's personal experience were reviewed.

RESULTS

Rates of reoperation range from 4% to 25% for adolescent idiopathic scoliosis and are higher for neuromuscular or syndromic diagnoses. The most common indications for revision are infection, increased deformity, late operative site pain, pseudarthrosis, and implant dislodgement. Because revision cases are unique, preoperative planning should include a review of previous records and imaging for a thorough understanding of the bony and neurologic anatomy and instrumentation. Preoperative discussion with colleagues may help prevent the need for additional revision. Measures to minimize blood loss should be taken. Deformity correction may include mobilization by multiple osteotomies for long sweeping curves, or focal osteotomies (e.g., vertebral column resection or pedicle subtraction osteotomies) for focal deformity. If fusing additional levels, instrumentation should have adequate fixation and should connect to existing anchors so that the corrective force can be applied to the site of deformity. The possibility of occult infection should be considered; in the event of a late deep infection, options include removing implants and debriding the spine. However, there is a risk of increased deformity in the coronal and sagittal planes after implant removal. Because revision surgery itself may have a higher subsequent reoperation rate, thorough preparation should be done to ensure success.

CONCLUSION

Cases of spine revision surgery in the pediatric population are best undertaken by an experienced surgeon and should involve thorough preoperative planning, proper equipment, and skilled assistance.

Revision rates following primary adult spinal deformity surgery: six hundred forty-three consecutive patients followed-up to twenty-two years postoperative

STUDY DESIGN

Retrospective study.

OBJECTIVE

To analyze the prevalence of and reasons for unanticipated revision surgery in an adult spinal deformity population treated at one institution.

SUMMARY OF BACKGROUND DATA

No recent studies exist that analyze the rate or reason for unanticipated revision surgery for adult spinal deformity patients over a long period.

METHODS

All patients presenting for primary instrumented spinal fusion with a diagnosis of adult deformity at a single institution from 1985 to 2008 were reviewed using a prospectively acquired database. All surgical patients with instrumented fusion of > or =5 levels using hooks, hybrid, or screw-only constructs were identified. Patient charts and radiographs were reviewed to provide information as to the indication for initial and any subsequent reoperation. A total of 643 patients underwent primary instrumented fusion for a diagnosis of adult idiopathic scoliosis (n = 432), de novo degenerative scoliosis (n = 104), adult kyphotic disease (n = 63), or neuromuscular scoliosis (n = 45). The mean age was 37.9 years (range, 18-84). Mean follow-up for the entire cohort was 4.7 years, and 8.2 years for the subset of the cohort requiring reoperation (range, 1 month-22.3 years).

RESULTS

A total of 58 of 643 patients (9.0%) underwent at least one revision surgery and 15 of 643 (2.3%) had more than one revision (mean 1.3; range, 1-3). The mean time to the first revision was 4.0 years (range, 1 week-19.7 years). The most common reasons for revision were pseudarthrosis (24/643 = 3.7%; 24/58 = 41.4%), curve progression (13/643 = 2.0%; 13/58 = 20.7%), infection (9/643 = 1.4%; 9/58 = 15.5%), and painful/prominent implants (4/643 = 0.6%; 4/58 = 6.9%). Uncommon reasons consisted of adjacent segment degeneration (3), implant failure (3), neurologic deficit (1), and coronal imbalance (1). Revision rates over the follow-up period were: 0 to 2 years (26/58 = 44.8%), 2 to 5 years (17/58 = 29.3%), 5 to 10 years (7/58 = 12.1%), >10 years (8/58 = 13.8%).

CONCLUSION

Repeat surgical intervention following definitive spinal instrumented fusion for primary adult deformity performed at a single institution demonstrated a relatively low rate of 9.0%. The most common reasons for revision were predictable and included pseudarthrosis, proximal or distal curve progression, and infection.

Analysis of instrumentation/fusion survivorship without reoperation after primary posterior multiple anchor instrumentation and arthrodesis for idiopathic scoliosis

BACKGROUND

During the past 25 years, spinal instrumentation systems and surgical techniques used to treat idiopathic scoliosis have evolved, achieving fewer patient restrictions during arthrodesis healing, shorter constructs, and better correction. The purposes of this retrospective comparative study were to determine the survivorship of the implant/fusion without reoperation and the risk factors influencing such survival.

METHODS

From 1989 through 2002, 208 consecutive patients (index patient included, age 10-20 years) underwent primary posterior instrumentation and arthrodesis with the same multiple anchor implant system by one surgeon, a co-designer of the system. Two hundred seven were followed for more than 2 years; reoperation status was available for them at an average follow-up of 8.3 years. Twenty-one independent demographic, deformity, instrumentation, and process variables possibly influencing the need for reoperation were studied by comparing the reoperated group with the unreoperated group.

RESULTS

Nineteen patients (9.2%) had reoperation; 16 (7.7%) were for indications related to posterior spine instrumentation. Survival of the implant/fusion without reoperation for spine instrumentation-related indications was 96% (95% confidence interval [CI], 93.2-98.7%) at 5 years, 91.6% (95% CI, 86.9-96.3%) at 10 years, 87.1% (95% CI, 79.5-94.6%) at 15 years, and 73.7% (95% CI, 48.6-98.6%) at 16 years, when the number at risk was nine. Reoperation need was significantly influenced by two implant variables: transverse connector design (p=.0012) and the lower instrumented vertebra anchors used (p=.0004). At 9 years, the longest interval allowing comparison, survival of the implant/fusion without reoperation for these two variables was 100% (six subjects at risk) compared to 82% (95% CI, 74.2-90.3%) with 59 patients still at risk for reoperation for those who did not have them, p=.0014.

CONCLUSIONS

The most stable lower instrumented vertebra anchor configuration, bilateral pedicle screws, and the stronger transverse connector design, closed drop entry, provided the best survival of the implant/fusion without reoperation with this system and the techniques used at 9-year follow-up. We hope that this post-market study using survivorship techniques will be a guide for studies of other spinal implants.

Revision surgery after primary spine fusion for idiopathic scoliosis

STUDY DESIGN

Retrospective case series.

OBJECTIVE

The objective of this study was to review the overall prevalence of, and indications for, reoperations after the index spine fusion for idiopathic scoliosis at our center.

SUMMARY OF BACKGROUND DATA

Spine fusions for idiopathic scoliosis are expected to be the final therapeutic intervention in management. In a recent publication in 2006, reoperations after index spine fusion for idiopathic scoliosis were reported in 12.9% of patients at a single institution (n = 1046).

METHODS

A spinal deformity database search at our center identified all primary anterior, posterior, and circumferential spinal fusions performed for idiopathic scoliosis (1985-2003). A total of 1057 patients were identified whose mean age was 14.4 years (7-22 years) with minimum 2 year follow-up after index surgery. Study cohort consisted patients who underwent reoperation for any reason after index fusion procedure.

RESULTS

Of the 1057 spinal fusions for idiopathic scoliosis, 41 (3.9%) underwent reoperation. Primary surgeries were: 11 anterior spinal fusions, 25 posterior spinal fusions, and 5 circumferential spinal fusions. Mean follow-up was 5.7 years (2-10.8). Forty-seven additional procedures were performed during 46 reoperations at an average of 26 months after index procedure (1 week-73 months). Of the 47 reoperations, 20 (43%) were revision spinal fusions (for pseudarthroses, uninstrumented curve progression or junctional kyphosis), 16 (34%) because of infections (5 acute, 11 chronic), 7 (15%) for implant removals due to pain and/or prominence (4 complete, 3 partial), 2 (4%) were revision of loosened implants, and 2 (4%) were elective thoracoplasties.

CONCLUSION

This study documented a 3.9% overall reoperation rate at our medical center, a 3-fold lower reoperation rate than the previously reported 12.9%. The most common reoperations were for infections (34%), pseudarthroses (26%), and postoperative curve progression of the adjacent unfused spine (17%).

Adolescent idiopathic scoliosis (AIS) treated with arthrodesis and posterior titanium instrumentation: 8 to 12 years follow up without late infection

BACKGROUND

There are no data in the peer-reviewed literature regarding long term results in patients treated for AIS with a posterior titanium instrumentation. Therefore we assessed the outcome in 50 patients treated by titanium implant.

METHODS

A total of 50 patients with a mean age of 16.6 years were treated. In all patients, titanium hooks and pedicle screws were used in combination. The demographic data and the pre- and post-operative radiographs of all 50 patients were re-examined, and 49 of the 50 patients (98%) attended a radiological and clinical follow up-examination on average 10.1 years post-operatively. The clinical results were recorded by means of the SRS 24 questionnaire.

RESULTS

In the frontal plane, the mean pre-operative thoracic and lumbar curve had been 62.4 degrees and 43.5 degrees respectively, post-operatively the curves were reduced to 26.9 degrees and 16.3 degrees , resulting in a correction rate of 56.9% for thoracic and 62.5% for lumbar curve. At the follow up-evaluation, the Cobb angle of the thoracic and lumbar curve was 31.0 degrees and 21.3 degrees respectively, giving a final correction rate of 50.3% for thoracic, and 51.0% for lumbar curve. 7 of the 50 patients (14.3%) had undergo revision surgery for complications, but complete implant removal was necessary in only one case. Analysis of the SRS 24 questionnaire showed an average score of 95.8 points.

CONCLUSION

Posterior titanium instrumentation is a safe and effective procedure in the surgical correction of AIS. In this retrospective study with small patient number, it shows favourable long-term results; in particular, the loss of correction is low, no late infection occurred and there was a very high survival rate of the implant itself.

Reoperation after primary fusion for adult spinal deformity: rate, reason, and timing

STUDY DESIGN

Retrospective cohort study of consecutive patients undergoing primary fusion with segmental fixation for adult spinal deformity.

OBJECTIVE

We sought to determine the survivorship of primary fusion for adult spinal deformity and identify patient-specific predictors of complications requiring reoperation.

SUMMARY OF BACKGROUND DATA

Compared with the adolescent population, surgery for adult deformity is often more complex and technically difficult, contributing to a high reported rate of complications that can result in the need for reoperation. Reported complication rates vary widely.

METHODS

From 1999-2004 all patients who underwent primary instrumented fusion for nonparalytic adult spinal deformity at a single center were included. Inclusion criteria included minimum age at surgery of 20 years and minimum fusion length of 4 motion segments. Surgical, demographic, and comorbidity data were recorded. Reoperation was defined as any additional surgery involving levels of the spine operated on during the index procedure and/or adjacent levels. Comparisons were performed between patients who required reoperation and those who did not.

RESULTS

Eighty-nine patients met inclusion criteria. Endpoint (minimum 2 years follow-up or reoperation) was reached for 91%. Mean follow-up was 3.8 years. Cumulative reoperation rate was 25.8%. Survival was 86.4% at 1 year, 77.2% at 2 years, and 75.2% at 3 years. Reasons for reoperation included infection (n = 8), pseudarthrosis (n = 3), adjacent segment problems (n = 5), implant failure (n = 4), and removal of painful implants (n = 3). Multivariate analysis showed smoking was significantly higher in the reoperation group.

CONCLUSION

Using a strict definition of reoperation for a well-defined cohort, in the presence of relevant risk factors, many patients undergoing primary fusion for adult spinal deformity required reoperation. The results indicate that complex medical and surgical factors contribute to the treatment challenges posed by patients with adult spinal deformity. This represents the largest cohort reported to date of patients undergoing primary fusion using third-generation instrumentation techniques.

Inpatient complications, mortality, and discharge disposition after surgical correction of idiopathic scoliosis: a national perspective

BACKGROUND CONTEXT

Information about complications and mortality after surgery for correction of idiopathic scoliosis has been largely derived from single-institution series. Regional or national studies have been lacking.

PURPOSE

To report inpatient mortality, complications, and discharge disposition after surgical correction of idiopathic scoliosis on a national level.

STUDY DESIGN

Retrospective cohort study using National Inpatient Sample (NIS) administrative data.

PATIENT SAMPLE

All patients in the NIS with the primary diagnosis of idiopathic scoliosis who underwent a spinal fusion between 1993 and 2002 were included.

OUTCOME MEASURES

Inpatient complication rate, mortality rate, and adverse outcome defined by death or discharge to institution other than home.

METHODS

Outcome measures were abstracted from the NIS. Univariate and multivariate analyses were performed to analyze the effects of patient and hospital characteristics on outcome measures.

RESULTS

The NIS was used to identify 51,911 patients who underwent spinal fusion for idiopathic scoliosis in the United States from 1993 to 2002. The total inhospital complication rate was 14.9% for pediatric patients and 25.1% for adult patients. The inhospital mortality rate was 0.17% and 0.40% for pediatric and adult patients, respectively. Adverse outcome was noted in 2.3% of pediatric patients and 20.4% of adult patients. Pulmonary and postoperative hemorrhages/hematomas were the most common complications reported. Multivariate analysis for complications showed that morbidity was significantly lower for pediatric patients (odds ratio [OR] = 0.80; confidence interval [CI] = 0.68-0.94) and female patients (OR = 0.77; CI = 0.68-0.88). Patients with a preoperative comorbidity were 1.53 (CI = 1.32-1.76) times more likely to develop a complication. A single postoperative complication increased the mean length of stay by more than 2 days and increased the mortality rate, adverse outcome, and hospital charges significantly.

CONCLUSIONS

We have provided a national perspective on inpatient complications, mortality, and discharge disposition after spinal fusion for idiopathic scoliosis in the United States. The significant negative effects of postoperative complications on mortality and resource utilization have been demonstrated. Furthermore, we have identified adult age, male gender, and preoperative comorbidity as important risk factors and defined their impact on patient outcomes.

Adolescent idiopathic scoliosis - to operate or not? A debate article

Adolescent idiopathic scoliosis (AIS) represents a rare condition with a potentially detrimental impact on young patients. Despite vast clinical research and published treatment guidelines and algorithms, the optimal therapeutic choice for these patients remains highly controversial. While advocates of early surgery emphasize the benefits of surgical deformity correction with regard to physical and psychological outcome, the opponents base their arguments on the high risk of complications and a lack of documented subjective long-term outcome. In the present paper, the authors were invited to debate the opposite positions of "pro" versus "contra" surgical treatment of AIS, based on the currently available evidence and published guidelines.

Rate of complications in scoliosis surgery - a systematic review of the Pub Med literature

Background

Spinal fusion surgery is currently recommended when curve magnitude exceeds 40–45 degrees. Early attempts at spinal fusion surgery which were aimed to leave the patients with a mild residual deformity, failed to meet such expectations. These aims have since been revised to the more modest goals of preventing progression, restoring 'acceptability' of the clinical deformity and reducing curvature.

In view of the fact that there is no evidence that health related signs and symptoms of scoliosis can be altered by spinal fusion in the long-term, a clear medical indication for this treatment cannot be derived. Knowledge concerning the rate of complications of scoliosis surgery may enable us to establish a cost/benefit relation of this intervention and to improve the standard of the information and advice given to patients. It is also hoped that this study will help to answer questions in relation to the limiting choice between the risks of surgery and the "wait and see – observation only until surgery might be recommended", strategy widely used. The purpose of this review is to present the actual data available on the rate of complications in scoliosis surgery.

Materials and methods

Search strategy for identification of studies; Pub Med and the SOSORT scoliosis library, limited to English language and bibliographies of all reviewed articles. The search strategy included the terms; 'scoliosis'; 'rate of complications'; 'spine surgery'; 'scoliosis surgery'; 'spondylodesis'; 'spinal instrumentation' and 'spine fusion'.

Results

The electronic search carried out on the 1^st February 2008 with the key words "scoliosis", "surgery", "complications" revealed 2590 titles, which not necessarily attributed to our quest for the term "rate of complications". 287 titles were found when the term "rate of complications" was used as a key word. Rates of complication varied between 0 and 89% depending on the aetiology of the entity investigated. Long-term rates of complications have not yet been reported upon.

Conclusion

Scoliosis surgery has a varying but high rate of complications. A medical indication for this treatment cannot be established in view of the lack of evidence. The rate of complications may even be higher than reported. Long-term risks of scoliosis surgery have not yet been reported upon in research. Mandatory reporting for all spinal implants in a standardized way using a spreadsheet list of all recognised complications to reveal a 2-year, 5-year, 10-year and 20-year rate of complications should be established. Trials with untreated control groups in the field of scoliosis raise ethical issues, as the control group could be exposed to the risks of undergoing such surgery.

Surgical revision rates of hooks versus hybrid versus screws versus combined anteroposterior spinal fusion for adolescent idiopathic scoliosis

STUDY DESIGN

Multi-institution retrospective review.

OBJECTIVE

To determine the surgical revision rates of hook, hybrid, anteroposterior, and total pedicle screw constructs for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Much debate continues on the safety, efficacy, and cost of thoracic pedicle screws. Nonetheless, there are no large series that have evaluated the revision rate of various constructs in AIS to determine the need for repeat surgery, and therefore, the added indirect costs and risks of additional procedures.

METHODS

We retrospectively reviewed the surgical case logs of 1428 patients with AIS at 2 institutions from 1990 to 2004, and the clinical records and radiographs of revision cases. Patients were classified into 1 of 4 groups: hook, hybrid hook and screw, all pedicle screw, and combined anteroposterior fusion constructs. Overall, there were 65 (4.6%) returns to the operating room, or 55 (3.9%) cases after excluding infections without concomitant pseudarthrosis.

RESULTS

Of the 65 revision cases, there were 52 females and 13 males, at an average age at first surgery of 13.9 years (range, 9-18 years), and an average age at revision of 14.7 years (range, 12-23 years). For the revision cases, the average initial Cobb was 61.9 degrees (range 44 degrees -110 degrees ), and this was not statistically different within the cohorts (P > 0.05). In terms of revision rate, all hook constructs had a higher revision rate secondary to instrumentation failure when compared with screws, while both hook and hybrid constructs had an overall higher surgical revision rate when compared with screw constructs or anteroposterior constructs (all P <or= 0.05). The pseudarthrosis rate trended toward, but did not meet, statistical significance between these same groups.

CONCLUSION

All pedicle screw and anteroposterior constructs have a lower surgical revision rate when compared with hook and hybrid constructs. The hidden patient and financial costs of these findings should be considered when evaluating overall instrumentation efficacy.

Impact of spine surgery on signs and symptoms of spinal deformity

Paediatric scoliosis is associated with signs and symptoms including reduced pulmonary function, increased pain and impaired quality of life, all of which worsen during adulthood, even when the curvature remains stable. Spinal fusion has been used as a treatment for nearly 100 years. In 1941, the American Orthopedic Association reported that for 70% of patients treated surgically, outcome was fair or poor: an average 65% curvature correction was reduced to 27% at >2 year follow-up and the torso deformity was unchanged or worse. Outcome was worse in children treated surgically before age 10, despite earlier intervention. Today, a reduced magnitude of curvature obtained by spinal fusion in adolescence can be maintained for decades. However, successful surgery still does not eliminate spinal curvature and it introduces irreversible complications whose long-term impact is poorly understood. For most patients there is little or no improvement in pulmonary function. Some report improved pain after surgery, some report no improvement and some report increased pain. The rib deformity is eliminated only by rib resection which can dramatically reduce respiratory function even in healthy adolescents. Outcome for pulmonary function and deformity is worse in patients treated surgically before the age of 10 years, despite earlier intervention. Research to develop effective non-surgical methods to prevent progression of mild, reversible spinal curvatures into complex, irreversible structural deformities, is long overdue.

Metal levels in corrosion of spinal implants

Corrosion affects spinal instrumentations and may cause local and systemic complications. Diagnosis of corrosion is difficult, and nowadays it is performed almost exclusively by the examination of retrieved instrumentations. We conducted this study to determine whether it is possible to detect corrosion by measuring metal levels on patients with posterior instrumented spinal fusion. Eleven asymptomatic patients, with radiological signs of corrosion of their stainless steel spinal instrumentations, were studied by performing determinations of nickel and chromium in serum and urine. Those levels were compared with the levels of 22 patients with the same kind of instrumentation but without evidence of corrosion and to a control group of 22 volunteers without any metallic implants. Statistical analysis of our results revealed that the patients with spinal implants without radiological signs of corrosion have increased levels of chromium in serum and urine (P < 0.001) compared to volunteers without implants. Corrosion significantly raised metal levels, including nickel and chromium in serum and urine when compared to patients with no radiological signs of corrosion and to volunteers without metallic implants (P < 0.001). Metal levels measured in serum have high sensibility and specificity (area under the ROC curve of 0.981). By combining the levels of nickel and chromium in serum we were able to identify all the cases of corrosion in our series of patients. The results of our study confirm that metal levels in serum and urine are useful in the diagnosis of corrosion of spinal implants and may be helpful in defining the role of corrosion in recently described clinical entities such as late operative site pain or late infection of spinal implants.