Safety and efficacy of Isola instrumentation and arthrodesis for adolescent idiopathic scoliosis: two- to 12-year follow-up

Health-related quality of life in untreated versus brace-treated patients with adolescent idiopathic scoliosis: a long-term follow-up

STUDY DESIGN

The previous Scoliosis Research Society brace study (JBJS-A, 1995) included patients with adolescent idiopathic scoliosis (AIS) with moderate curve sizes (25 degrees -35 degrees). The Swedish patients in this study were examined in a long-term follow-up.

OBJECTIVE

The aim was to analyze and compare quality of life in adulthood between AIS patients who were only observed or treated with a brace during adolescence.

SUMMARY OF BACKGROUND DATA

Quality of life as measured by the SRS-22 has not previously been presented for adult untreated AIS patients.

METHODS

Forty patients who were only observed (due to a curve increase of less than 6 degrees until maturity), and 37 brace-treated patients attended the complete follow-up, including clinical and radiologic examination, and answered 2 quality of life questionnaires (SRS-22 and Short Form-36 [SF-36]).

RESULTS

No differences were found between the groups in terms of age at follow-up (mean: 32 years), follow-up time after maturity (mean: 16.0 years), and curve size at inclusion (mean: 30 degrees) or at follow-up (mean: 35 degrees). The SRS-22/total score was a mean of 4.2 for braced patients and 4.1 for only observed patients. Neither total scores/subscales of the SRS-22 or SF-36 differed significantly between the groups. For the SF-36, no differences in relation to the Swedish age-matched norm scales were found for either group.

CONCLUSION

Patients with moderate AIS report good quality of life in their 30s, as measured by both the SRS-22 and SF-36, regardless of whether they received no active treatment or were brace treated during adolescence. Neither of the groups displayed any difference compared with the age-matched norm groups for the SF-36.

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.

Quality of life in patients treated surgically for scoliosis: longer than sixteen-year follow-up

STUDY DESIGN

A retrospective study.

OBJECTIVE

To evaluate the long-term quality of life (QOL) of patients treated surgically for scoliosis.

SUMMARY OF BACKGROUND DATA

Measures of long-term outcome after surgery for scoliosis have focused mainly on radiologic changes. However, QOL issues such as working status and marital status are the subjects of greatest concern for patients who will undergo surgical treatment for scoliosis.

METHODS

Thirty-two patients treated surgically for scoliosis between 1976 and 1989 were included in this study. The mean duration of follow-up was 21.1 years. Eighteen patients had adolescent idiopathic scoliosis, 8 congenital scoliosis, and 6 symptomatic scoliosis. We evaluated long-term outcome by direct interview with patients. Working status, marital status, and childbearing were determined in addition to clinical and radiologic evaluation. Patients were also asked to fill out the short form (SF)-36 and Scoliosis Research Society (SRS)-22 questionnaires.

RESULTS

Twenty-seven patients (84.4%) were or had been engaged in various occupations without marked difficulty. Although none of the male patients was married, 62.5% of the female patients were married. Half of the female patients had delivered babies after surgery, and the mean number of such children was 1.83. On the SF-36, none of the scores for subjects with idiopathic or congenital scoliosis were markedly different from those for age-matched healthy controls. Multivariate logistic regression analysis revealed that marked preoperative Cobb angle and positive sagittal balance at the most recent follow-up were significantly associated with increased odds ratio for poor scores on the SRS-22.

CONCLUSION

We evaluated long-term QOL in patients treated surgically for scoliosis, and found that it was not impaired, particularly in the case of patients with idiopathic or congenital scoliosis. Larger preoperative Cobb angle and positive sagittal balance at the most recent follow-up were related to poor outcome in QOL as assessed by the SRS-22.

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.

Surgery for idiopathic scoliosis: currently applied techniques

This review discusses the basic knowledge and recent innovation of surgical treatment for scoliosis. Surgical treatment for scoliosis is indicated, in general, for a curve exceeding 45 to 50 degrees by the Cobb's method on the basis that: Curves larger than 50 degrees progress even after skeletal maturity.Curves larger than 60 degrees cause loss of pulmonary function, and much larger curves cause respiratory failure.Greater the curve progression, the more difficult it is to treat with surgery. Posterior fusion with instrumentation has been the standard form of surgical treatment for scoliosis. In modern instrumentation systems, more anchors are used to connect the rod and the spine, resulting in better correction and less frequent implant failures. Segmental pedicle screw constructs or hybrid constructs using pedicle screws, hooks, and wires are the trend of today. Anterior instrumentation surgery was once the choice of treatment for thoracolumbar and lumbar scoliosis because better correction could be obtained with shorter fusion levels. But in the recent times, superiority of anterior surgery for the thoracolumbar and lumbar scoliosis has been questioned. Initial enthusiasm for anterior instrumentation for the thoracic curve using video assisted thoracoscopy has faded out.

Surgical treatment of main thoracic scoliosis with thoracoscopic anterior instrumentation. a five-year follow-up study

BACKGROUND

The surgical outcomes in patients with scoliosis at two years following anterior thoracoscopic spinal instrumentation and fusion have been reported. The purpose of this study was to evaluate the results at five years.

METHODS

A consecutive series of forty-one patients with major thoracic scoliosis treated with anterior thoracoscopic spinal instrumentation was evaluated at regular intervals. Prospectively collected data included patient demographics, radiographic measurements, clinical deformity measures, pulmonary function, an assessment of intervertebral fusion, and the scores on the Scoliosis Research Society (SRS-24) outcomes instrument. Perioperative and postoperative complications were recorded. Patient data for the preoperative, two-year, and five-year postoperative time points were compared. In addition, a univariate analysis compared selected two-year radiographic, pulmonary function, and SRS-24 data of the study cohort and those of the patients lost to follow-up.

RESULTS

Twenty-five (61%) of the original forty-one patients had five-year follow-up data and were included in the analysis. Between the two-year and five-year follow-up visits, no significant changes were observed with regard to the average percent correction of the major Cobb angle (56% +/- 11% and 52% +/- 14%, respectively), average total lung capacity as a percent of the predicted value (95% +/- 14% and 91% +/- 10%), and the average total SRS-24 score (4.2 +/- 0.4 and 4.1 +/- 0.7). Radiographic evaluation of intervertebral fusion at five years revealed convincing evidence of a fusion with remodeling and trabeculae present at 151 (97%) of the 155 instrumented motion segments. No postoperative infections or clinically relevant neurovascular complications were observed. Rod failure occurred in three patients, and three patients required a surgical revision with posterior spinal instrumentation and fusion.

CONCLUSIONS

Thoracoscopic anterior instrumentation for main thoracic idiopathic scoliosis results in five-year outcomes comparable with those reported previously for open anterior and posterior techniques. The radiographic findings, pulmonary function, and clinical measures remain stable between the two and five-year follow-up time points. Thoracoscopic instrumentation provides a viable alternative to treat spinal deformity; however, the risks of pseudarthrosis, hardware failure, and surgical revision should be considered along with the advantages of limited muscular dissection and improved scar appearance.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Adolescent idiopathic scoliosis (AIS) - an indication for surgery? A systematic review of the literature

PURPOSE

Historically, the treatment options for AIS, the most common form of scoliosis are: Exercises, in-patient rehabilitation, braces and surgery. While there is evidence in the form of prospective controlled studies that Scoliosis Intensive Rehabilitation (SIR) and braces can alter the natural history of the condition, there is no review on prospective controlled trials for surgical treatment. The aim of this review was to perform a systematic search of the Pub Med literature to reveal the evidence on scoliosis surgery.

METHODS

A systematic review has been performed using the Pub Med database. Literature has been searched for the outcome parameter; 'rate of progression' and only prospective controlled studies that have considered the treatment versus the natural history have been included.

RESULTS

No controlled study, not in the short, mid or long term, searched within the review, has been found to reveal evidence to support the hypothesis that the effects of surgery as a treatment option for AIS is superior to natural history.

CONCLUSIONS

No evidence has been found in terms of prospective controlled studies to support surgical intervention from the medical point of view. In the light of the unknown long-term effects of surgery and in concluding on the lack of evidence already found that surgery might change the signs and symptoms of scoliosis, a randomized controlled trial (RCT) is long overdue. Until such a time that such evidence exists, there can be no medical indication for surgery. The indications for surgery are limited for cosmetic reasons in severe cases and only if the patient and the family agree with this.

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.

Restoration of thoracic kyphosis by posterior instrumentation in adolescent idiopathic scoliosis: comparative radiographic analysis of two methods of reduction

STUDY DESIGN

A retrospective comparison of radiographic results for 2 consecutive series of patients treated for adolescent idiopathic scoliosis (AIS) by posterior instrumentations with thoracic screws using 2 methods of reduction: sequential approximation by cantilever reduction (CR) and simultaneous translation technique on 2 rods (ST2R).

OBJECTIVE

To compare correction of thoracic hypokyphosis and coronal radiographic results between the 2 methods of reduction.

SUMMARY OF BACKGROUND DATA

Publications concerning AIS confirm the moderate correction of thoracic hypokyphosis by posterior instrumentation with hooks and also with pedicle screws.

METHODS

Forty-four patients with AIS (Lenke type 1, 2, 3) underwent a posterior spinal fusion and instrumentation (CR series: 21 patients--ST2R series: 23 patients). Three groups of preoperative kyphosis were generated: 12 patients with severe hypokyphosis (<or=10 degrees ) (5 in CR series and 7 in ST2R series); 12 patients with mild hypokyphosis (10-20 degrees ) (5 and 7 patients, respectively) and 20 with normal kyphosis (>20 degrees ) (11 and 9 patients, respectively). Thoracic kyphosis (T4-T12) and Cobb angle measurements of major and minor curves were evaluated by an independent observer. The minimum follow-up was 2 years.

RESULTS

At final follow-up, regarding patients with a severe preoperative hypokyphosis, the mean gain was 14 degrees in the CR series (8 degrees preoperative-22 degrees postoperative) and 27 degrees in the ST2R series (3-30 degrees ) (P = 0.018). Concerning patients with mild hypokyphosis, the mean gains were, respectively, 8 degrees (17-25 degrees ) and 18 degrees (16-34 degrees ) (P = 0.052). After surgery, 3 patients of CR series had hypokyphosis whereas the patients of the ST2R series all had normal kyphosis. In coronal plane, the mean correction of scoliosis was similar for both groups (75% vs. 69%; P = 0.177).

CONCLUSION

Simultaneous translation on 2 rods provides a better correction of thoracic kyphosis than the sequential approximation by CR on patients with preoperative hypokyphosis. This surgical technique restores normal thoracic kyphosis in all cases.

Surgical treatment of scoliosis: a review of techniques currently applied

In this review, basic knowledge and recent innovation of surgical treatment for scoliosis will be described. Surgical treatment for scoliosis is indicated, in general, for the curve exceeding 45 or 50 degrees by the Cobb's method on the ground that:

1) Curves larger than 50 degrees progress even after skeletal maturity.

2) Curves of greater magnitude cause loss of pulmonary function, and much larger curves cause respiratory failure.

3) Larger the curve progress, more difficult to treat with surgery.

Posterior fusion with instrumentation has been a standard of the surgical treatment for scoliosis. In modern instrumentation systems, more anchors are used to connect the rod and the spine, resulting in better correction and less frequent implant failures. Segmental pedicle screw constructs or hybrid constructs using pedicle screws, hooks, and wires are the trend of today.

Anterior instrumentation surgery had been a choice of treatment for the thoracolumbar and lumbar scoliosis because better correction can be obtained with shorter fusion levels. Recently, superiority of anterior surgery for the thoracolumbar and lumbar scoliosis has been lost. Initial enthusiasm for anterior instrumentation for the thoracic curve using video assisted thoracoscopic surgery technique has faded out.

Various attempts are being made with use of fusionless surgery. To control growth, epiphysiodesis on the convex side of the deformity with or without instrumentation is a technique to provide gradual progressive correction and to arrest the deterioration of the curves. To avoid fusion for skeletally immature children with spinal cord injury or myelodysplasia, vertebral wedge ostetomies are performed for the treatment of progressive paralytic scoliosis. For right thoracic curve with idiopathic scoliosis, multiple vertebral wedge osteotomies without fusion are performed. To provide correction and maintain it during the growing years while allowing spinal growth for early onset scoliosis, technique of instrumentation without fusion or with limited fusion using dual rod instrumentation has been developed. To increase the volume of the thorax in thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis, vertical expandable prosthetic titanium ribs has been developed.

Neural complications in the surgical treatment of adolescent idiopathic scoliosis

STUDY DESIGN

Multicenter, prospective, consecutive clinical series.

OBJECTIVE

To report on neural complications in a prospective cohort study of 1301 children undergoing spinal fusion and instrumentation for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The incidence of neural complications for spinal deformity surgery has been reported to be 0.26% to 17%. However, most studies have relied on retrospective voluntary reporting of nonconsecutive cases.

METHODS

A review of 1301 consecutive surgical cases was conducted using the Prospective Pediatric Scoliosis Study database, which is maintained by the Spinal Deformity Study Group.

RESULTS

There were 9 neural complications. There were 3 thecal penetrations, none of which required repair, and none of which demonstrated intraoperative neural monitoring changes or postoperative clinical sequelae. There were 2 nerve root injuries. In 1 nerve root injury, a positional compression femoral neurapraxia resolved over 6 months. The other was an L4 neurapraxia despite lowest instrumented vertebra L1, and resolved spontaneously by 3 months' follow-up. There were 4 spinal cord injuries. One required removal of implants and fusion in situ, 1 required relaxation of correction and in situ fusion with instrumentation, while the other 2 were observed after fusion and instrumentation with reduction. All resolved spontaneously within 3 months after operation.

CONCLUSION

The neural complication rate was 0.69%. Two thecal penetrations were due to medial placement of pedicle screws, and 1 was due to dissection during spine exposure. If these are eliminated, as they imply intraspinal entry but not direct neural injury, together with 1 positional neurapraxia, which is remote from the surgical field, our complication rate is 0.38%. This is consistent with other studies in the North American Literature, including multiple reports from the Scoliosis Research Society. Common themes are significant curve correction producing neural stretch and the use of sublaminar wires. None of the neural injuries was permanent. These results reaffirm that surgical treatment of adolescent idiopathic scoliosis has a low but real neural complication rate.

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.

A prospective study of brace treatment versus observation alone in adolescent idiopathic scoliosis: a follow-up mean of 16 years after maturity

STUDY DESIGN

The Swedish patients included in the previous SRS brace study were invited to take part in a long-term follow-up.

OBJECTIVE

To investigate the rate of scoliosis surgery and progression of curves from baseline as well as after maturity.

SUMMARY OF BACKGROUND DATA

Brace treatment was shown to be superior to electrical muscle stimulation, as well as observation alone, in the original SRS brace study. Few other studies have shown that brace treatment is effective in the treatment of scoliosis.

METHODS

Of 106 patients, 41 in Malmö (all Boston brace treatment) and 65 in Göteborg (observation alone as the intention to treat), 87% attended the follow-up, including radiography and chart review. All radiographs were (re)measured for curve size (Cobb method) by an unbiased examiner. Searching in the mandatory national database for performed surgery identified patients who had undergone surgery after maturity.

RESULTS

The mean follow-up time was 16 years and the mean age at follow-up was 32 years The 2 treatment groups had equal curve size at inclusion. The curve size of patients who were treated with a brace from the start was reduced by 6 degrees during treatment, but the curve size returned to the same level during the follow-up period. No patients who were primarily braced went on to undergo surgery. In patients with observation alone as the intention to treat, 20% were braced during adolescence due to progression and another 10% underwent surgery. Seventy percent were only observed and increased by 6 degrees from inclusion until now. No patients underwent surgery after maturity. Progression was related to premenarchal status.

CONCLUSION

The curves of patients with adolescent idiopathic scoliosis with a moderate or smaller size at maturity did not deteriorate beyond their original curve size at the 16-year follow-up. No patients treated primarily with a brace went on to undergo surgery, whereas 6 patients (10%) in the observation group required surgery during adolescence compared with none after maturity. Curve progression was related to immaturity.

Clinical and radiographic results after implant removal in idiopathic scoliosis

STUDY DESIGN

Prospective radiographic and clinical analysis of patients with idiopathic scoliosis who had complete implant removal following posterior spinal fusion (PSF) at least 2 years previously.

OBJECTIVE

To evaluate the clinical and radiographic effect of implant removal after PSF for idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Occasionally, implants must be removed following instrumented PSF. Indications for removal include infection and late operative site pain. Previously, it has been thought that there was little morbidity associated with implant removal in the presence of a solid fusion. However, recent studies have reported loss of coronal correction after implant removal in patients who had a PSF for adolescent idiopathic scoliosis. Few long-term studies have assessed the clinical or radiographic results of complete implant removal after PSF.

METHODS

We identified 56 patients who had undergone PSF for idiopathic scoliosis and subsequently had complete removal of all instrumentation. None of these patients had a pseudarthrosis at the time of implant removal. After IRB approval, 43 of 56 (77%) patients returned for new standing posteroanterior and lateral spine radiographs and completion of an SRS-22 questionnaire.

RESULTS

For the 43 patients who had new radiographs and completed an SRS-22, the time from the original PSF to complete implant removal averaged 2.9 years (range, 7 months to 7.25 years). Twenty-two patients had implants removed because of infection, and 21 patients had implants removed secondary to pain. The average time from implant removal to completion of the most recent radiographs and SRS-22 questionnaire was 9.5 years (range, 3.2-17.9 years). Patients were considered to have had progression of deformity after implant removal if their Cobb angle measurements increased by more than 10 degrees . Two patients had 11 degrees to 20 degrees of coronal plane progression of their main thoracic curve. No patient had more than 10 degrees of coronal plane progression of a lumbar curve. Sagittal curve progression was identified more frequently. Nineteen patients had between an 11 degrees and 20 degrees increase in thoracic kyphosis, and 5 patients had >20 degrees of thoracic kyphosis progression. Patients with >20 degrees of thoracic kyphosis progression after implant removal had greater thoracic kyphosis before surgery and larger main thoracic and lumbar coronal curves at the time of implant removal. Progressive kyphosis did not correlate with: reason for implant removal, length of follow-up, or time from fusion to implant removal. Although total SRS-22 scores correlated inversely with increased thoracic kyphosis, this trend did not reach statistical significance.

CONCLUSION

Implant removal after PSF for idiopathic scoliosis may be complicated by progression of deformity. Patients requiring implant removal should be appropriately counseled and monitored.

Idiopathic scoliosis treated with Cotrel-Dubousset instrumentation: evaluation 10 years after surgery

STUDY DESIGN

Prospective cohort study with 10-year follow-up.

OBJECTIVE

To evaluate long-term results after operative treatment with Cotrel-Dubousset (CD) instrumentation for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Limited knowledge exists in the evaluation of long-term function with quality of life measures after CD instrumentation in patients with AIS.

METHODS

A total of 100 (76 females and 24 males) consecutive AIS patients all with single primary curves were included. Radiologic measures and pain were registered at baseline and at 1- to 5-year follow-up. Quality of life and back specific measures, including EuroQol (EQ) and Oswestry Disability Index (ODI), were obtained by a questionnaire mailed to the patients at 10 years after surgery.

RESULTS

Mean age at operation was 16.8 (SD, 5.3) years, mean Risser sign was Grade 3.2 (SD, 1.5). All patients were observed for 2 years. The average primary curve was reduced from 56 degrees to 19 degrees, and this correction was maintained during follow-up. Fourteen patients had minor complications, and 5 patients had implants removed because of late clinically suspected infections. A total of 86 patients answered the 10-year questionnaire; 97% of the patients considered back function as excellent, good, or fair, and 96% would have done the operation again. Scores for EQ-5D and ODI were slightly worse than in the normal population. Despite this observation, 45% of the patients reported to have consulted a physician or received physiotherapy for back pain during the last year before the 10-year follow-up.

CONCLUSION

Radiologic results, patient satisfaction, and mean scores for quality of life and back function were excellent after CD instrumentation for AIS, but a considerable number of patients had treatment for back problems.

What impact does spinal deformity correction for adolescent idiopathic scoliosis make on quality of life?

STUDY DESIGN

: Literature review.

OBJECTIVE

: To identify scientifically sound studies that have reported changes in quality of life (QOL) after spinal deformity correction in patients with adolescent idiopathic scoliosis (AIS) and to discuss these findings.

SUMMARY OF BACKGROUND DATA

: Few studies have been published. Most are retrospective cohort studies and lack both preoperative and postoperative data for the outcome in terms of QOL.

METHODS

: A review of existing literature with the emphasis on spinal fusion for AIS and outcome as measured by health-related QOL was performed.

RESULTS

: Thirteen studies of various quality were found after reviewing the papers. Only 3 of them contained both preoperative and postoperative data on QOL, using the SRS-22/-24. They all reported a statistically significant improvement in some of the domain scores. The clinical implications of these findings are unclear, as the minimal clinically important differences for SRS-22/-24 have not yet been established.

CONCLUSION

: Weak evidence (Level IV) exists in the literature that spinal deformity correction for AIS does not significantly impact QOL in short-term or mid-term. The interpretation of this must be that there were no serious adverse events after surgery.

Accuracy analysis of pedicle screw placement in posterior scoliosis surgery: comparison between conventional fluoroscopic and computer-assisted technique

STUDY DESIGN

The accuracy of pedicle screw placement was evaluated in posterior scoliosis surgeries with or without the use of computer-assisted surgical techniques.

OBJECTIVE

In this retrospective cohort study, the pedicle screw placement accuracy in posterior scoliosis surgery was compared between conventional fluoroscopic and computer-assisted surgical techniques.

SUMMARY OF BACKGROUND DATA

There has been no study systemically analyzing the perforation pattern and comparative accuracy of pedicle screw placement in posterior scoliosis surgery.

METHODS

The 45 patients who received posterior correction surgeries were divided into 2 groups: Group C, manual control (25 patients); and Group N, navigation surgery (20 patients). The average Cobb angles were 73.7 degrees and 73.1 degrees before surgery in Group C and Group N, respectively. Using CT images, vertebral rotation, pedicle axes as measured to anteroposterior sacral axis and vertebral axis, and insertion angle error were measured. In perforation cases, the angular tendency, insertion point, and length abnormality were evaluated.

RESULTS

The perforation was observed in 11% of Group C and 1.8% in Group N. In Group C, medial perforations of left screws were demonstrated in 8 of 9 perforated screws and 55% were distributed either in L1 or T12. The perforation consistently occurred in pedicles in which those axes approached anteroposterior sacral axis within 5 degrees . The average insertion errors were 8.4 degrees and 5.0 degrees in Group C and Group N, respectively, which were significantly different (P < 0.02).

CONCLUSION

The medial perforation in Group C occurred around L1, especially when pedicle axis approached anteroposterior sacral axis. This consistent tendency was considered as the limitation of fluoroscopic screw insertion in which horizontal vertebral image was not visible. The use of surgical navigation system successfully reduced the perforation rate and insertion angle errors, demonstrating the clear advantage in safe and accurate pedicle screw placement of scoliosis surgery.

Comparative analysis of pedicle screw versus hybrid instrumentation in adolescent idiopathic scoliosis surgery

The expectations of both the patient and surgeon have been greatly revised in the last 10 years with the introduction of pedicle screws (PS) in spinal surgery. In this study, we have retrospectively evaluated and compared the results of PS instrumentation and the Hybrid System (HS), the latter consists of pedicle screws, sublaminar wire and hooks. The mean follow-up period was 60.1 months (range: 49-94 months) for the patients of the HS group and 29.3 months (range: 24-35 months) for those of the PS group. In the HS group, pedicle screws were used at the thoracolumbar junction and lumbar vertebra, the bilateral pediculotransverse claw hook configuration was used at the cranial end of the instrumentation, sublaminar wire was used on the concave side of the apical region and the compressive hook was used on the convex side. In the PS group, PS were used on the concave sides at all levels and on the convex side of the cranial and caudal end of instrumentation, in the transition zone and at the apex. The two groups were comparable for variables such as mean age, preoperative Cobb angle, thoracic kyphosis angle, lordosis angle, coronal balance, flexibility of the curve, apical vertebra rotation (AVR), apical vertebra rotation (AVT) and the number of vertebrae included in the fusion (p>0.05). The parameters of values of correction, ratio of correction loss, AV derotation, AVT correction ratio, amount of blood loss, operation time, postoperative global coronal and sagittal balance, thoracic kyphosis angle and lumbar lordosis angle were measured at the last follow-up and used for comparing the HS and PS groups. There was no statistically significant difference between the groups for correction ratio, postoperative coronal balance, postoperative thoracic kyphosis and lumbar lordosis angle, operation time, amount of blood loss and number of fixation points (p>0.05) The difference for the ratio of correction loss, AV derotation angle and the AVT correction ratio at the last follow-up visit and for the total follow-up period between the groups was found to be statistically significant (p<0.05). Although it is possible to obtain a similar amount of correction by either instrumentation system, the loss of correction seems to be lower with the more rigid PS construction. The PS system also has a stronger effect on vertebral bodies, thereby providing better AV de-rotation. There was no significant difference (p>0.05) between the groups in terms of correction rate, postoperative coronal and sagittal balance, operation time, blood loss and number of fixation points. This may indicate that anchor points are more important than the use--or not--of screws. Correction durability and AV de-rotation was better with PS instrumentation, while AVT was better corrected by HS instrumentation (p<0.05). We propose that the reason for the better correction of AVT with HS instrumentation is the forceful translation offered by the sublaminar wire at the apical region, while the reason for the better correction durability of the PS instrumentation may be due to the fact that multiple pedicle screws which afford three-column control are better at maintaining the correction and preventing late deterioration.

Repeat surgical interventions following "definitive" instrumentation and fusion for idiopathic scoliosis

STUDY DESIGN

A retrospective chart review was performed on all idiopathic scoliosis patients treated with instrumented spinal fusion over a 15-year period.

OBJECTIVES

To provide an experience from a single institution over a prolonged time period. The goal was to determine the frequency of repeat surgical interventions following the "definitive" spinal fusion surgery and identify the factors responsible for these reoperations.

SUMMARY OF BACKGROUND DATA

Instrumented spinal fusion remains the standard of care in the surgical management of idiopathic scoliosis. This surgery is considered a "definitive" procedure where, barring a complication, no additional surgical procedures are planned. Although many studies have reported the frequency of specific complications following spinal fusion, little information currently exists regarding the cumulative average of these repeat surgical interventions that occur following these "definitive" procedures.

METHODS

Surgical logs were reviewed on all patients who had an instrumented spinal fusion for idiopathic scoliosis from January 1988 through December 2002. All subsequent surgical interventions on these patients were then identified from the logs through December 2004. Pertinent information was gleaned from surgical logs and patient charts to provide details for these reoperations.

RESULTS

A total of 1,046 patients underwent an instrumented spinal fusion for idiopathic scoliosis: 809 had a posterior-only fusion, 228 had an anterior-only fusion, and 9 had a combined anterior/posterior spinal fusion. A total of 172 repeat surgical interventions were performed in 135 patients (12.9%). Of these 135 patients, 29 patients (21.5%) had two or more separate procedures performed. The most common reasons for reoperation were infection, symptomatic implant, and pseudarthrosis. Patients who had posterior fusions had a significantly higher rate of reoperation than patients who had anterior fusions (14.0% vs. 9.3%). Reoperations due to infections and symptomatic implants occurred with significantly higher frequency in the posterior spine fusion group compared with those with anterior spinal fusion. No differences in rates of reoperation for pseudarthrosis were noted between posterior and anterior fusion groups.

CONCLUSIONS

Repeat surgical interventions are relatively common following these supposedly definitive surgical procedures. The most common reasons for return to surgery are infection, symptomatic implant, and pseudarthrosis.

Fusionless surgery for scoliosis: 2-17 year radiographic and clinical follow-up

STUDY DESIGN

Descriptive case series.

OBJECTIVE

To determine whether fusionless, multiple vertebral wedge osteotomy can safely obtain correction of the deformity with adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

To our knowledge, no such attempts to manage the AIS with fusionless, vertebral osteotomies have been reported.

METHODS

A total of 20 consecutive patients were treated since 1987. Deformity correction, complications, respiratory function, and patient-oriented outcome were investigated.

RESULTS

There were 20 patients (17 females and 3 males), including 19 with idiopathic and 1 with syringomyelia scoliosis, who underwent surgery at an average age of 16.4 years and were followed for 8.9 years (range 2-17) on average. There were no neurologic complications. One superficial wound infection necessitated debridement. There were 2 patients converted to posterior instrumentation surgery because of deterioration of the deformity. The average Cobb angle of 64.0 degrees before surgery was corrected to 48.2 degrees at 8.9 years after surgery. Decline of the pulmonary function test after surgery was not statistically significant. The patients' responses to questions about function and pain were favorable.

CONCLUSION

Deformity with AIS was safely corrected with fusionless, multiple vertebral wedge osteotomy.

A biomechanical analysis of sublaminar and subtransverse process fixation using metal wires and polyethylene cables

STUDY DESIGN

An in vitro biomechanical calf thoracic spine study.

OBJECTIVE

To evaluate the biomechanical stability of sublaminar and subtransverse process fixation using stainless steel wires and ultra-high molecular weight polyethylene (UHMWPE) cables.

SUMMARY OF BACKGROUND DATA

It is commonly held that transverse process fixation provides less stability than sublaminar fixation. To our knowledge, this is the first biomechanical study to compare the stability afforded by sublaminar fixation and subtransverse process fixation using metal wire and UHMWPE cable before and after cyclic loading.

METHODS

There were 6 fresh-frozen calf thoracic spines (T4-T9) used to determine the sublaminar fixation stiffness and subtransverse process fixation stiffness in each group. Double strands of 18-gauge stainless steel wire, 3 and 5 mm-width UHMWPE cable (Nesplon; Alfresa, Inc., Osaka, Japan) were applied to each spine. Cyclic pure flexion-extension moment loading (2 Nm, 0.5 Hz, 5000 cycles) was applied after the initial stability was analyzed by measuring the range of motion. Statistical analyses were used to delineate differences between the various experimental groups.

RESULTS

Subtransverse process wiring was more stable than sublaminar wiring after cyclic loading in flexion-extension (P < 0.05). There were no significant differences between each group in lateral bending and axial rotation after cyclic loading. Sublaminar stainless steel wiring was more stable than sublaminar 3 and 5-mm cable before and after cyclic loading in axial rotation (P < 0.01). Acute subtransverse process fixation using 3-mm cable was less stable after cyclic loading in axial rotation (P < 0.05). All other groups did not produce statistically significant differences.

CONCLUSIONS

Subtransverse process fixation provides at least as much stability as sublaminar fixation. A 5-mm UHMWPE cable and stainless steel wire result in equivalent sublaminar and subtransverse process stability.

Minimum 10 years follow-up surgical results of adolescent idiopathic scoliosis patients treated with TSRH instrumentation

Last two decades witnessed great advances in the surgical treatment of idiopathic scoliosis. However, the number of studies evaluating the long-term results of these treatment methods is relatively low. During recent years, besides radiological and clinical studies, questionnaires like SRS-22 assessing subjective functional and mental status and life-quality of patients have gained importance for the evaluation of these results. In this study, surgical outcome and Turkish SRS-22 questionnaire results of 109 late-onset adolescent idiopathic scoliosis patients surgically treated with third-generation instrumentation [Texas Scottish Rite Hospital (TSRH) System] and followed for a minimum of 10 years were evaluated. The balance was analyzed clinically and radiologically by the measurement of the lateral trunk shift (LT), shift of head (SH), and shift of stable vertebra (SS). Mean age of the patients was 14.4+/-1.9 and mean follow-up period was 136.9+/-12.7 months. When all the patients were included, the preoperative mean Cobb angle of major curves in the frontal plane was 60.8 degrees +/-17.5 degrees . Major curves that were corrected by 38.7+/-22.1% in the bending radiograms, postoperatively achieved a correction of 64.0+/-15.8%. At the last follow-up visit, 10.3 degrees +/-10.8 degrees of correction loss was recorded in major curves in the frontal plane with 50.5+/-23.1% final correction rate. Also, the mean postoperative and final kyphosis angles and lumbar lordosis angles were 37.7 degrees +/-7.4 degrees , 37.0 degrees +/-8.4 degrees , 37.5 degrees +/-8.7 degrees , and 36.3 degrees +/-8.5 degrees , respectively. A statistically significant correction was obtained at the sagittal plane; mean postoperative changes compared to preoperative values were 7.9 degrees and 12.9 degrees for thoracic and lumbar regions, respectively. On the other hand, normal physiological thoracic and lumbar sagittal contours were achieved in 83.5% and 67.9% of the patients, respectively. Postoperatively, a statistically significant correction was obtained in LT, SH, and SS values (P<0.05). Although, none of the patients had completely balanced curves preoperatively, in 95.4% of the patients the curves were found to be completely balanced or clinically well balanced postoperatively. This rate was maintained at the last follow-up visit. Overall, four patients (3.7%) had implant failure. Early superficial infection was observed in three (2.8%) patients. Radiologically presence of significant consolidation, absence of implant failure, and correction loss, and clinical relief of pain were considered as the proof of a posterior solid fusion mass. About ten (9.2%) patients were considered to have pseudoarthrosis: four patients with implant failure and six patients with correction loss over 15 degrees at the frontal plane. About four (3.7%) patients among the first 20 patients had neurological deficit only wake-up test was used for neurological monitoring of these patients. No neurological deficit was observed in the 89 patients for whom intraoperative neurological monitoring with SSEP and TkMMEP was performed. Overall, average scores of SRS-22 questionnaire for general self-image, function, mental status, pain, and satisfaction from treatment were 3.8+/-0.7, 3.6+/-0.7, 4.0+/-0.8, 3.6+/-0.8, and 4.6+/-0.3, respectively at the last follow-up visit. Results of about 10 years of follow-up these patients treated with TSRH instrumentation suggest that the method is efficient for the correction of frontal and sagittal plane deformities and trunk balance. In addition, it results in a better life-quality.

Prospective evaluation of 50 consecutive scoliosis patients surgically treated with thoracoscopic anterior instrumentation

STUDY DESIGN

Prospective, consecutive, single-surgeon case series of patients treated for scoliosis with thoracoscopic anterior spinal instrumentation.

BACKGROUND

A thoracoscopic approach for insertion of anterior instrumentation has been developed in the past 10 years, which obviates many of the disadvantages of the open anterior thoracic approach. The morbidity associated with a thoracoscopy is limited because of the minimal skin and chest wall dissection required with this method.

PURPOSE

The purpose of this evaluation is to report a single surgeon's experience with an initial series of 50 patients. The goal is to report the outcomes with regards to the radiographic findings, pulmonary function, and the SRS Outcomes Instrument, as well as a review of the perioperative data and complications.

METHODS

The primary author's initial 50 thoracoscopic anterior spinal instrumentation patients were consecutively collected. Data collection included demographics, such as age, gender, and diagnosis. Data regarding the surgical procedure included the operative time, intraoperative estimated blood loss, as well as the number of levels instrumented anteriorly. In the perioperative hospital period, data were collected with regard to the length of the hospital stay, the number of days in the ICU, the number of days of ventilator support, and the number of days after surgery when conversion from IV to PO pain medication occurred. Radiographic data were obtained systematically on each patient and measured by authors other than the surgeon. The SRS 22 and/or 24 Outcomes Questionnaire and pulmonary function tests were administered to patients at similar intervals.

RESULTS

The series consisted of 44 females and 6 males with a mean age of 14 years (range, 9-48 years). Forty-five of the 50 patients were available for clinical and radiographic evaluation at greater than or equal to 2 years after surgery. The average length of follow-up for these 45 patients was 33 months (range, 2-5 years). The mean operative time for the procedure was 350 +/- 50 minutes and ranged from 265 to 528 minutes. The estimated intraoperative blood loss averaged 431 +/- 273 mL (range, 75-1,400 mL). Normalizing the operative time and estimated blood loss based on the number of levels treated resulted in an average operative time per level of 48 +/- 6 minutes per level and an estimated intraoperative blood loss per level of 60 +/- 37 mL per level. The preoperative thoracic Cobb averaged 53 degrees +/- 9 degrees (range, 40 degrees-80 degrees). At most recent follow-up (> or = 2 years), the thoracic Cobb averaged 24 degrees +/- 7 degrees. Implant failure occurred in 3 cases.

CONCLUSION

Thoracoscopic anterior instrumentation for adolescent idiopathic scoliosis is a viable surgical option. The outcomes of this consecutive series of patients is comparable to prior open and endoscopic series presented in the literature. The technical challenges of this operation are evident in the learning curve effect, which has been demonstrated.