Submuscular Isola rod with or without limited apical fusion in the management of severe spinal deformities in young children: preliminary report

Effects of Sustained Tensile Distraction on Vertebrae and Intervertebral Disc Growth: An in Vivo Study Using a Mouse Tail Model

BACKGROUND

Directed growth modulation is commonly utilized as a surgical treatment for early-onset scoliosis. Growing rods are instrumented on the spine and apply sustained tension on the immature spine for a substantial amount of time, with the clinical goal of accommodating axial expansion of the spine. Despite the use of growing rods in humans, the mechanobiology of the spinal tissues under tensile loading remains relatively unknown. To bridge this knowledge gap, we developed a preclinical mouse model that allows for mechanistic investigations of sustained tension on the spine.

METHODS

Using custom 3D-printed washers and tunable springs, we distracted across the seventh and ninth caudal vertebrae of adolescent and young adult C57BL/6 female mice with forces that were approximately 2 times the body mass of the animal. The springs were replaced weekly to maintain tension for the duration of the experiment. A set of 6-week-old animals were first instrumented for 10 weeks to evaluate the feasibility and tolerability. Subsequently, the 6- and 12-week-old experimental animals were instrumented until they were 20 weeks of age in order to evaluate the effects of tension until adulthood. The spines were monitored using digital radiography and micro-computed tomography (µCT), and the intervertebral discs (IVDs) were evaluated using mechanical testing and compositional assays.

RESULTS

The device was well tolerated and caused no notable complications. The tensile forces lengthened the vertebrae in the 6-week-old animals that were instrumented for 14 weeks and in the 12-week-old animals that were instrumented for 8 weeks. Increased IVD heights were observed in the 6-week-old animals but not in the 12-week-old animals. The porosity of the vertebral end plates increased following instrumentation in all groups but progressively recovered over time.

CONCLUSIONS

Distraction accelerated the lengthening of the vertebrae and the heightening of the IVD, with no observable degeneration or decline in the mechanical performance of the IVDs for these distraction conditions.

CLINICAL RELEVANCE

This model will be useful for investigating how spinal tissues adapt to directed growth modulation with maturation and aging.

Surgical Treatment of Spinal Deformities in Pediatric Orthopedic Patients

Scoliosis and Scheuermann's disease are common spinal deformities that affect a substantial population, particularly adolescents, often impacting their quality of life. This comprehensive review aims to present a detailed understanding of these conditions, their diagnosis, and various treatment strategies. Through an extensive exploration of current literature, the review discusses the etiology of these spinal deformities and the use of diagnostic tools such as X-rays and MRI. It further delves into the range of treatment options available, from conservative approaches such as physiotherapy and bracing to more invasive surgical interventions. The review underscores the necessity of an individualized treatment approach, taking into account factors such as the patient's age, the severity of the curvature, and overall health. This all-encompassing perspective on scoliosis and Scheuermann's disease will aid in evidence-based decision making in their management with the goal of improving patient outcomes.

Effects of spinal deformities on lung development in children: a review

Scoliosis before the age of 5 years is referred to as early-onset scoliosis (EOS). While causes may vary, EOS can potentially affect respiratory function and lung development as children grow. Moreover, scoliosis can lead to thoracic insufficiency syndrome when aggravated or left untreated. Therefore, spinal thoracic deformities often require intervention in early childhood, and solving these problems requires new methods that include the means for both deformity correction and growth maintenance. Therapeutic strategies for preserving the growing spine and thorax include growth rods, vertically expandable titanium artificial ribs, MAGEC rods, braces and casts. The goals of any growth-promoting surgical strategy are to alter the natural history of cardiorespiratory development, limit the progression of underlying spondylarthrosis deformities and minimize negative changes in spondylothorax biomechanics due to the instrumental action of the implant. This review further elucidates EOS in terms of its aetiology, pathogenesis, pathology and treatment.

Early-onset scoliosis: a narrative review

Early-onset scoliosis (EOS) is defined as any spinal deformity that is present before 10 years old, regardless of etiology.

Deformity must be evaluated based on the intercorrelation between the lungs, spine, and thorax.

Curvatures of early-onset have increased risk of progression, cardiorespiratory problems, and increased morbidity and mortality.

Progression of the deformity may produce thoracic insufficiency syndrome, where a distorted thorax is unable to support normal respiratory function or lung growth.

Management and treatment of EOS should pursue a holistic approach in which the psychological impact and quality of life of the patient are also taken into consideration.

Growth-friendly surgical techniques have not met the initial expectations of correcting scoliotic deformity, promoting thoracic growth, and improving pulmonary function.

[Nonfusion procedures in pediatric scoliosis]

The treatment of early onset scoliosis (EOS) in children is a complex and demanding challenge in the treatment of spinal deformities. Conservative treatment with physiotherapy is indicated in mild forms with a Cobb angle from 10° and additionally a corset treatment with a Cobb angle of more than 20°. After exhaustion of the conservative measures or a progression of spinal scoliosis of 10° or deformities of more than 35°, a surgical approach should be considered in order to prevent respiratory insufficiency as well as severe postural and thoracic deformities. In situations where growth is still ongoing fusion operations can lead to stunted growth, a crankshaft phenomenon or degeneration of alignment. Meaningful alternatives to a fusion are so-called growing rods as a distraction-based nonfusion technique, e.g. traditional growing rods (TGR) and magnetically controlled growing rods (MCGR) or as a further method a vertical expandable prosthetic titanium rib (VEPTR) device. The advantages and disadvantages of each operative procedure must be considered with respect to the risk profile of each patient and the experience of the surgeon in order to guarantee the best possible treatment.

The growth-friendly surgical treatment of scoliosis in children with osteogenesis imperfecta using distraction-based instrumentation

PURPOSE

The study was undertaken to determine the feasibility of growth-friendly distraction-based surgery in children with OI.

METHODS

Two multi-center databases were queried for children with OI who had undergone GR or VEPTR surgery. Inclusion criteria were a minimum 2-year follow-up and three lengthening procedures following the initial implantation. Details of the surgical techniques, surgical complications, and radiographic measurements of deformity correction, T1-T12 and T1-S1 elongation and growth were recorded.

RESULTS

Five patients were identified. There was one patient with type I OI and two patients each with type III and type IV. Four patients had GR constructs and one a VEPTR construct. The initial scoliosis deformity averaged 80° (70°-103°), and the subsequent corrections averaged 32% for initial correction, 48% at last follow-up, and 54% for the two patients that had a final fusion. The T1-T12 and T1-S1 growth averaged 31 mm and 44 mm respectively, and yearly growth averaged 4 mm and 6 mm, respectively. Growth was notably much less in those with more severe disease. There were 13 complications in 4 patients. Nine of the 10 surgical complications were anchor failures which were corrected in 7 planned and 2 un-planned procedures. Significant migration occurred in one patient with severe OI type III.

CONCLUSION

The results varied in this heterogeneous population. In general, satisfactory deformity corrections were obtained and maintained, modest growth was obtained, and complications were similar to those reported in other series of growth-friendly surgery. Limited growth and significant anchor migration are to be anticipated in this population.

LEVEL OF EVIDENCE

IV.

Magnetically controlled growing rods in the treatment of early onset scoliosis: a single centre experience of 44 patients with mean follow-up of 4.1 years

AIMS

Magnetically controlled growing rods (MCGR) have been gaining popularity in the management of early-onset scoliosis (EOS) over the past decade. We present our experience with the first 44 MCGR consecutive cases treated at our institution.

METHODS

This is a retrospective review of consecutive cases of MCGR performed in our institution between 2012 and 2018. This cohort consisted of 44 children (25 females and 19 males), with a mean age of 7.9 years (3.7 to 13.6). There were 41 primary cases and three revisions from other rod systems. The majority (38 children) had dual rods. The group represents a mixed aetiology including idiopathic (20), neuromuscular (13), syndromic (9), and congenital (2). The mean follow-up was 4.1 years, with a minimum of two years. Nine children graduated to definitive fusion. We evaluated radiological parameters of deformity correction (Cobb angle), and spinal growth (T1-T12 and T1-S1 heights), as well as complications during the course of treatment.

RESULTS

The mean Cobb angles pre-operatively, postoperatively, and at last follow-up were 70° (53 to 103), 35° (15 to 71) and 39° (15 to 65) respectively (p < 0.001). Further, there was a mean of 14° (-6 to 27) of additional Cobb angle correction upon graduation from MCGR to definitive fusion. Both T1-T12 and T1-S1 showed significant increase in heights of 27 mm and 45 mm respectively at last follow-up (p < 0.001). Ten children (23%) developed 18 complications requiring 21 unplanned operations. Independent risk factors for developing a complication were single rod constructs and previous revision surgery.

CONCLUSION

MCGR has the benefit of avoiding multiple surgeries, and is an effective tool in treatment of early-onset scoliosis. It also maintains the flexibility of the spine, allowing further correction at the time of definitive fusion.Cite this article: Bone Joint Open 2020;1-7:405-414.

Unplanned return to operation room (OR) following growing spinal constructs (GSCs) in early onset scoliosis (EOS)-a multi-centric study

PURPOSE

To evaluate the incidence and risk factors associated with the unplanned return to OR in EOS.

METHODS

Medical records of 51 patients of EOS operated at three different centres using various types of GSCs were evaluated for complications requiring unplanned surgeries. Data were analysed to find out rate of unplanned surgeries in relation to the aetiology, age and Cobb angle at index surgery, type of implant, cause of unplanned surgery, and management required.

RESULTS

Out of 51 patients, three did not meet inclusion criteria. Forty-eight patients of EOS operated by GSCs with a mean age of 6.7 years (range 2-12 years) with an average follow-up of 67.3 months were studied. There were 30 congenital, 10 idiopathic, 4 syndromic, and 4 neuromuscular cases. Thirty-nine out of 48 patients had one or more unplanned surgeries on follow-up (81.25%). Out of total 248 surgeries following index procedure, 82 were unplanned surgeries (33.06%), including 53 implant revisions, 12 implant-removal, 14 debridement, and 2 flaps. The common complications were 24.14% rod/screw breakage, 42.53% anchor pull-out, 16.09% infections, 6.90% wound dehiscence, and 4.6% neuro deficits. Unplanned surgeries were significantly higher in syndromic (58.8%) and neuromuscular (52.9%) than congenital (27.2%) and idiopathic (37.8%) cases (p < 0.05). Age at index procedure < 5 years had higher unplanned surgeries than age > 5 years (2.5 and 1.23 per patient, respectively,  p < 0.05). Type of implant and initial Cobb angle did not significantly affect the rate of unplanned surgeries (p  > 0.05) CONCLUSION: GSCs in EOS require a frequent revisit to operation room which should be well understood by the surgeon and parents.

Magnetic Controlled Growth Rods in the Treatment of Scoliosis: Safety, Efficacy and Patient Selection

Early-onset scoliosis is defined as a spinal curvature greater than 10° in children prior to 10 years of age. Untreated EOS may lead to progressively severe spinal deformity, impaired pulmonary development, restrictive lung disease, and both increased morbidity and mortality. Limitations of established conservative treatments include inability to correct severe deformity, as well as challenges with compliance when casting and bracing is applied. In addition, surgical treatment in the form of traditional growing rods requires regular surgical lengthenings and is associated with complications inherent with repeated invasive procedures and exposure to general anesthesia. MAGEC is an evolving magnetically controlled growing rod system for the treatment of EOS. After initial implantation, lengthening is achieved non-invasively by using magnetic external remote control. MAGEC offers the potential to control moderate and severe EOS, while avoiding repeated surgical procedures and associated complications. In this review, we examine the results from clinical, radiological and explant studies following the use of MAGEC, in the context of other established and emerging treatments for EOS.

Synovial fluid cell counts and its role in the diagnosis of paediatric septic arthritis

PURPOSE

Clinical presentation of paediatric septic arthritis (SA) can be similar to other joint pathologies. Despite potential for infection in all major joints, most diagnostic criteria are based on values from the hip. This study identifies the best joint aspirate values in diagnosing SA in all joints.

METHODS

In all, 166 patients who underwent 172 joint aspirations at the authors' institution between 01 September 2004 and 01 September 2014 were retrospectively identified. Recorded measures included age, sex, duration of symptoms, fever history, weight-bearing status, aspiration results, serum results and antibiotic administration. Patients were placed in the following four categories: 'culture confirmed SA' (C-SA), 'suspected SA' (S-SA), 'Other' and 'Other-rheumatologic' (Other-R), a subcategory of 'Other'.

RESULTS

Most common sites of aspiration were the knee (55%) and hip (29%). Diagnostic grouping was as follows: C-SA = 44, S-SA = 45, Other = 83 (Other-R = 21). Fever and non-weight-bearing prior to admission were useful predictors of SA, though in C-SA patients, 21% did not have a fever and 23% could weight bear at the time of admission. Aspirate white blood cell (WBC) count was significantly greater in both C-SA (92 000 cells/hpf) and S-SA (54 000) than in Other (10 000) and Other-R (18 000) patients. The percentage of polymorphonuclear (%PMN) was also significantly greater in C-SA (81.1%) and S-SA (80.9%) than in Other (57.9%) and Other-R (63.3%).

CONCLUSION

Joint aspirate values, especially %PMN, are valuable in diagnosing SA. Additionally, antibiotics pre-aspiration did not affect %PMN, facilitating subsequent diagnosis of infection. Lastly, while aspirate WBC count was a valuable indicator of SA, this finding is not as definitive as previous research suggests.

LEVEL OF EVIDENCE

IV Case Series.

Preliminary Study of a New Growing Rod System in Immature Swine Model

BACKGROUND

Growing rod techniques have been demonstrated to be a valuable treatment in early-onset scoliosis; however, repeated surgeries and general anesthesia cannot be avoided.

METHODS

This study included 12 immature swine that were randomly assigned to receive either a novel growing rod system (experimental group) or a traditional growing rod system (control group). Lengthening was undertaken at 4-week intervals, for a total observation period of 12 weeks. Radiography, computed tomography, and motion analysis of the spine were conducted to evaluate rod extension, growth and nonfusion of the spine, and fixation.

RESULTS

One swine (control group) was excluded from the analysis because of a deep wound infection at 1 week after the initial operation. No complications were observed in the remaining 11 swine. In the experimental group, the average lengthening operation lasted 12.1 ± 3.1 minutes, and average incision length was 1.1 ± 0.2 cm; both values were significantly less compared with the control group (P < 0.001). No significant between-group differences in mean trunk length, body mass, or thickness of cephalad-instrumented or caudad-instrumented vertebrae and intervertebral disks were present before the initial operation or at the final assessment (12 weeks after operation; P > 0.05). Spinal growth and motion of instrumented spinal segments were conserved.

CONCLUSIONS

The novel growing rod system is safe and effective in immature swine, preserving spine growth potential and involving less surgical trauma.

Clinical Impact of Corrective Cast Treatment for Early Onset Scoliosis: Is It a Worthwhile Treatment Option to Suppress Scoliosis Progression Before Surgical Intervention?

BACKGROUND

Although corrective cast (CC) has been back in use for the treatment of early onset scoliosis (EOS), no studies have reported how clinically meaningful CC was in comparison with brace-only treatment (BT) in EOS. The aim of this study was to investigate the effect of CC treatment in terms of suppression of scoliosis progression before surgery.

METHODS

This study was designed to conduct a comparison of patients treated at 2 spine institutions differing in treating methods (one: mainly CC with brace, the other: BT). Applying casts were performed without general anesthesia and repeatedly with the interval of 2 to 6 months combined with corrective brace application called alternatively repetitive cast and brace treatment (ARCBT). In total, 58 patients met the following criteria: (1) age at the first visit ≤6 years, (2) scoliosis ≥40 degrees, (3) conservative treatment≥2 years. Patients with congenital scoliosis were excluded in this study. In total, 58 patients were divided into 2 groups; cast/brace group (C/B-G) and BT group (B-G).

RESULTS

There were no significant differences of diagnosis (P=0.2773), sex (P=0.0670), age at the first visit (P=0.1457), scoliosis magnitude (P=0.1980), and duration for conservative treatment (P=0.2578) between 2 groups. Most of the patients who were treated with ARCBT, were switched to BT due to lower compliance for CC after the age of around 7 years. The progression of scoliosis during ARCBT and BT were 4.4 and 5.8 degree/y, respectively. Those during ARCBT in C/B-G was 2.8 degree/y comparing with 8.4 degree/y after switch to BT after 7 years of age. There was a significant difference between scoliosis progression during ARCBT in C/B-G and that of B-G (P=0.0086).

CONCLUSIONS

This study showed that ARCBT had a significant impact on suppression of scoliosis progression compared with BT in EOS. However, the termination of cast application and the switch to BT may be still a clinical question considering the time to surgical intervention.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Pressure distributions inside intervertebral discs under unilateral pedicle screw fixation in a porcine spine model

Background

Little data are available regarding the effects of pedicle screws on the intervertebral disc stress for different spinal segments. The aim of this study was to analyze the intervertebral disc stress in response to the placement of pedicle screws.

Methods

T3–4, T11–12, T15–L1, L3–4, and L4–5 intervertebral disc segments from six porcine spine specimens were harvested. A compressive load of 200 N was applied both before and after the pedicle screw was implanted on the left side of each target segment; the resulting pressure was measured during vertical, 5° anterior flexion, 5° posterior extension, and 5° lateral bending.

Results

The posterior intradiscal pressures of the intervertebral disc were significantly lower in the fixed group than in the unfixed group for all segments during vertical, 5° anterior flexion, and 5° posterior extension. The left pressures of the intervertebral disc were significantly lower in the fixation group for all segments. During 5° lateral bending, the left intervertebral disc pressures were significantly lower in the fixation group. Lower mean pressures were observed in the fixed group.

Conclusions

Unilateral pedicle screws can effectively reduce the pressure of the fixed lateral intervertebral disc. Moreover, it can change the pressure distribution of the intervertebral disc and reduce the pressure of the entire intervertebral disc, especially the posterior side of the intervertebral disc.

Unplanned Reoperations in Magnetically Controlled Growing Rod Surgery for Early Onset Scoliosis With a Minimum of Two-Year Follow-Up

STUDY DESIGN

A retrospective review of prospectively collected clinical and radiologic data of patients with magnetically controlled growing rods (MCGRs) from a multi-centered study with a minimum of 2-year follow-up.

OBJECTIVE

The aim of this study was to describe the incidence and causes of unplanned reoperations and to report the outcomes of patients treated with MCGR for early-onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Published clinical studies have demonstrated that MCGR is safe and effective for curvature control of EOS, and can avoid repeated surgeries for distractions. However, there have been no reports on the unplanned reoperations and complications of MCGR for EOS with a large series of patients.

METHODS

Between 2009 and 2012, 30 patients with EOS underwent MCGR implantation in six institutions. A retrospective review of prospectively collected clinical and radiologic data with a minimum of 2-year follow-up was conducted. Demographic data, radiologic measurements, unplanned reoperations, and other complications were noted. Risk factors for unplanned reoperations were analyzed.

RESULTS

Patients underwent MCGR implantation at the mean age of 7.2 years. The mean follow-up period was 37 months. Fourteen patients (46.7%) underwent an unplanned reoperation within the follow-up period, with a mean time to reoperation of 23 months after initial surgery (range, 5-48 months). Causes of unplanned reoperation were failure of rod distractions, proximal foundation failure, rod breakage, and infection. More frequent distractions (between 1 week and 2 months) were associated with a higher rate of reoperation than distraction frequencies between 3 and 6 months (71% vs. 25%).

CONCLUSION

This is the largest series with the longest follow-up to date that examines the need for additional unplanned surgery after the initial procedure. It highlights that MCGR surgery can be associated with unplanned reoperations, and more frequent distractions may be a risk factor. Long-term comparative studies with traditional growing rod are required to evaluate the effectiveness of this implant.

LEVEL OF EVIDENCE

4.

Magnetically controlled growing rod in early onset scoliosis: a 30-case multicenter study

PURPOSE

Preliminary results of magnetically controlled growing rods (MCGR) are encouraging. However, only short case series of MCGR for the treatment of early onset scoliosis (EOS) have been reported. Our aim was to evaluate its effectiveness and complications.

METHODS

We report a 30-case retrospective, consecutive, multicenter series of MCGR. Effectiveness was judged upon: deformity correction and difficulties to achieve desired distraction. Secondary endpoints included complications and revision surgeries.

RESULTS

Median age at surgery was 9.1 years (5-13). Mean follow-up was 18.4 months (12-33.9). Mean Cobb angle was 66° preoperatively and 44° at latest follow-up. MCGR has avoided an average of 2.03 scheduled surgical procedures per patient compared to traditional growing rod (GR). The intended total length gain was 40.1 mm per patient (5-140) and the total measured length gain was 21.9 mm (45.5% discrepancy). There were 24 complications: 7 proximal pull-outs of the hooks, 3 rod breakages, 6 failures of the lengthening of which 4 complete blockages and 2 complete blockages followed by backtracking, 1 proximal junctional kyphosis, 1 wound dehiscence, 1 superficial infection, 1 deep infection requiring implant removal, 1 pulmonary embolism, 1 pulmonary insufficiency, 1 secondary lumbar scoliosis, and 1 painful outpatient distraction. Eight patients had a gradual loss of effectiveness of distractions. There were 13 revision surgeries in 9 patients.

CONCLUSIONS

MCGR provides satisfactory deformity correction and avoids repeated surgical procedures for lengthening. However, it has substantial complication rate. Although less frequent than in GR, the law of diminishing returns also applies to MCGR.

Flexible growing rods: a biomechanical pilot study of polymer rod constructs in the stability of skeletally immature spines

Background

Surgical treatments for early onset scoliosis (EOS) correct curvatures and improve respiratory function but involve many complications. A distractible, or ‘growing rod,’ implant construct that is more flexible than current metal rod systems may sufficiently correct curves in small children and reduce complications due to biomechanical factors. The purpose of this pilot study was to determine ranges of motion (ROM) after implantation of simulated growing rod constructs with a range of clinically relevant structural properties. The hypothesis was that ROM of spines instrumented with polymer rods would be greater than conventional metal rods and lower than non-instrumented controls.

Methods

Biomechanical tests were conducted on six thoracic spines from skeletally immature domestic swines (35–40 kg). Paired pedicle screws were used as anchors at proximal and distal levels. Specimens were tested under the following conditions: control, then dual rods of polyetheretherketone (PEEK) (diameter 6.25 mm), titanium (4 mm), and cobalt-chrome alloy (CoCr) (5 mm). Lateral bending (LB) and flexion-extension (FE) moments were applied, and vertebral rotations were measured. Differences were determined by two-tailed t-tests and Bonferroni for four primary comparisons: PEEK vs control and PEEK vs CoCr, in LB and FE (α = 0.05/4).

Results

In LB, ROM of spine segments after instrumenting with PEEK rods was lower than the non-instrumented control condition at each instrumented level. ROM was greater with PEEK rods than with Ti and CoCr rods at every instrumented level. Combining treated levels, in LB, ROM for PEEK rods was 35 % of control (p < 0.0001) and 270 % of CoCr rods (p < 0.01). In FE, ROM with PEEK was 27 % of control (p < 0.001) and 180 % of CoCr (p < 0.01). At proximal and distal adjacent non-instrumented levels in FE, mean ROM was lower for PEEK than for either metal.

Conclusions

PEEK rods increased flexibility versus metal rods, and decreased flexibility versus non-instrumented controls, both over the entire instrumented segment and at each individual level. Smaller mean increases in ROM at proximal and distal adjacent motion segments occurred with PEEK compared to metal rods, which may help decrease complications, such as junctional kyphosis. Flexible growing rods may eventually help improve treatment options for young patients with severe deformity.

Growing rod erosion through the lamina causing spinal cord compression in an 8-year-old girl with early-onset scoliosis

BACKGROUND CONTEXT

Early-onset scoliosis often occurs by the age of 5 years and is attributed to many structural abnormalities. Syndromic early-onset scoliosis is considered one of the most aggressive types of early-onset scoliosis. Treatment starts with serial casting and bracing, but eventually most of these patients undergo growth-sparing procedures, such as a single growing rod, dual growing rods, or a vertical expandable titanium prosthetic rib.

PURPOSE

This case report aimed to describe an unusual complication of erosion of a growing rod through the lamina that caused spinal cord compression in an 8-year-old girl with early-onset scoliosis.

STUDY DESIGN

This is a case report.

METHODS

A retrospective chart review was used to describe the clinical course and radiographic findings of this case after rod erosion into the spinal canal.

RESULTS

The patient underwent successful revision surgery removing the rod without neurologic complications.

CONCLUSIONS

Patients with syndromic early-onset scoliosis are more prone to progressive curves and severe rotational deformity. We believe that the severe kyphotic deformity in addition to the dysplastic nature of the deformity in this population may predispose them to this unusual complication.

Shilla Growth Guidance for Early-Onset Scoliosis: Results After a Minimum of Five Years of Follow-up

BACKGROUND

The Shilla growth guidance technique was developed to allow growth during treatment of a child's spinal deformity without requiring repeated surgery for lengthening procedures. Dual stainless-steel rods are fixed posteriorly to the corrected apex via pedicle screws with a limited fusion at the apex and are combined with sliding pedicle screws to allow vertebral growth in a cephalad and caudad direction.

METHODS

A retrospective study of the original forty patients treated with the Shilla method for a severe deformity of a growing spine was performed to determine the efficacy of the procedure.

RESULTS

The etiology of the spinal deformity in the forty patients was idiopathic in nine, congenital in one, neuromuscular in sixteen, and syndromic in fourteen. The average age at the index surgery was six years and eleven months, and the average duration of follow-up for the thirty-three eligible patients was seven years (range, four years and nine months to ten years and nine months). The curves averaged 69° (range, 40° to 115°) preoperatively and 38.4° (range, 16° to 74°) at the time of the most recent follow-up or prior to definitive spinal instrumentation and fusion. Complications included secondary infections (six patients), alignment issues (eight patients), and implant-related problems (twenty-four patients), with some patients experiencing more than one complication.

CONCLUSIONS

The Shilla growth guidance technique is a method of scoliosis treatment that allows spinal growth while controlling the deformity without scheduled repeated surgical procedures. The complication rate is high (73%) but acceptable, and children with a wide variety of diagnoses can be safely treated with the Shilla procedure.

A Preliminary Study on a Novel Growth Guidance Rod System for Early-Onset Scoliosis in a Sheep Model

STUDY DESIGN

An animal study with immature sheep to evaluate the effects of a multisegment growth guidance rod (MSGGR) on spine growth.

OBJECTIVE

To determine whether the spine of the immature sheep can still grow after MSGGR fixation.

SUMMARY OF BACKGROUND DATA

The disadvantages for current growing rod techniques are that they can partially correct only the spinal curve and have little control to the apex of the curve. The rigidity of the spine after a growing rod procedure may also interfere with the final correction. Current systems are complex and not always affordable, especially in the developing world. Newer, more inexpensive techniques that provide 3-dimensional deformity correction while allowing normal spinal growth without surgical lengthening are still desired.

METHODS

The MSGGR is a rod consisting of segments. Spinal deformation in scoliosis is corrected and maintained by the rods without fusion. The system allows the growth of the fixed spinal segments. It is stable when twisted and bent but extendable when stretched. Rod extension occurs through sliding between the segments along the sockets in accordance to the growth of the spine. Ten 3-month-old immature sheep were used in this study. Dual MSGGRs were implanted to fix the lumber and low thoracic spine. Radiographs, magnetic resonance image, and computed tomographic scan of the spine were obtained to evaluate the fixation, rod extension, and spine health.

RESULTS

All of the sheep spines grew with the implants in position. The spine segments within the instruments were 12.5 ± 0.8 cm and grew by 10.9% (range: 6%-18.4%) from their original length in 4 months. None of the implants failed. No MSGGR-related complications were observed. Magnetic resonance imaging showed normal disc within the instrumented segments. Motion of the instrumented spinal segments was conserved.

CONCLUSION

Growth guidance with this novel MSGGR allowed for continued growth in this sheep model, and repeated surgical lengthening of the system is not needed.

LEVEL OF EVIDENCE

N/A.

Self-growing Instrumentation With Gliding Connectors for Collapsing Spine Deformities in Children: A Novel Technique

BACKGROUND

The optimal management of young children with neuromuscular spinal deformities is currently unknown. A number of spinal instrumentation techniques have been proposed in early-onset scoliosis to achieve "guided growth," each with its drawbacks.

OBJECTIVE

To report a novel self-growing spinal instrumentation technique, designed to avoid recurrent surgeries in children with neuromuscular disease.

METHODS

The technique is based on the control of apical and end vertebrae by pedicle screw fixation and limited fusion. Standard 4.5 to 5.5 mm side-to-side rod connectors are used as gliding connections. Three children with neuromuscular disease underwent the described procedure. The patients were followed for an average of 36 months (range, 24 to 60 mo).

RESULTS

All patients who underwent the procedure showed an average spinal growth of 1.1 mm/year, which is comparable with normative growth data and previous reports using growing rods. One patient required the exchange of dislodged rods, secondary to the amount of growth of the spine. There were no other complications or unplanned surgeries during the follow-up period.

CONCLUSIONS

This novel method provided growth in a group of 3 patients with collapsing neuromuscular spine deformities.

LEVEL OF EVIDENCE

Level IV-case series.

Growing Rods Versus Shilla Growth Guidance: Better Cobb Angle Correction and T1-S1 Length Increase But More Surgeries

STUDY DESIGN

Retrospective comparison.

OBJECTIVES

To compare treatment of early-onset scoliosis (EOS) with Shilla growth guidance versus distraction-based dual growing rods (GR).

SUMMARY OF BACKGROUND DATA

We are not aware of any prior studies comparing the Shilla procedure with other surgical procedures in the treatment of EOS.

METHODS

The authors performed a multicenter case-matched comparison of patients with EOS treated with Shilla versus dual spine-spine GR from 1995 to 2009. A total of 36 Shilla patients from 3 centers were matched with 36 GR patients from the database by age at index surgery (±1 year), preoperative Cobb angle (±15°), and diagnosis (neuromuscular, congenital, idiopathic, or syndromic). Average follow-up was similar between groups (GR, 4.3 years; Shilla, 4.6 years; p = .353).

RESULTS

Average Cobb angle improvement preoperatively to latest follow-up was 36° (range, 72° to 36°) in the GR group versus 23° (range, 69° to 45°) in the Shilla group (p = .0124). T1-S1 length increased 8.8 cm in patients treated with GR, compared with 6.4 cm in Shilla patients (p = .0170). Shilla patients had fewer surgeries (2.8) than patients in the GR group (7.4) (p < .001) but had a higher rate of unplanned surgeries for implant complications (Shilla, 1.3; GR, 0.5; p = .0151). When revisions for implant complications done at the time of scheduled lengthenings and revisions for construct maintenance were included, the groups did not differ significantly in the number of procedures for implant complications (Shilla, 1.4; GR, 1.5; p = .9451). The overall complication rate did not differ significantly between groups (Shilla, 1.9 [range, 0-7]; GR, 1.3 [range, 0-9]; p = .2085).

CONCLUSIONS

The GR group had a greater improvement in Cobb angle and a greater increase in T1-S1 length than Shilla. The GR patients had more surgeries but Shilla patients had more unplanned procedures. The rate of complications overall did not differ significantly between groups.

Apical and intermediate anchors without fusion improve Cobb angle and thoracic kyphosis in early-onset scoliosis

BACKGROUND

The main goal of treatment in early-onset scoliosis is to obtain and maintain curve correction while simultaneously preserving spinal, trunk, and lung growth. This study introduces a new surgical strategy, called the modified growing rod technique, which allows spinal growth and lung development while controlling the main deformity with apical and intermediate anchors without fusion. The use of intraoperative traction at the initial procedure enables spontaneous correction of the deformity and decreases the need for forceful correction maneuvers on the immature spine and prevents possible implant failures. This study seeks to evaluate (1) curve correction; (2) spinal length; (3) number of procedures performed; and (4) complications with the new approach.

DESCRIPTION OF TECHNIQUE

In the initial procedure, polyaxial pedicle screws were placed with a muscle-sparing technique. Rods were placed in situ after achieving correction with intraoperative skull-femoral traction. The most proximal and most distal screws were fixed and the rest of the screws were left with nonlocked set screws to allow vertical growth. The lengthening reoperations were performed every 6 months.

METHODS

Between 2007 and 2011, we treated 19 patients surgically for early-onset scoliosis. Of those, 16 (29%) were treated with the modified growing rod technique by the senior author (AH); an additional three patients were treated using another technique that was being studied at the time by one of the coauthors (CO); those three were not included in this study. The 16 children included nine girls and seven boys (median, 5.5 years of age; range, 4-9 years), and all had progressive scoliosis (median, 64°; range, 38°-92°). All were available for followup at a minimum of 2 years (median, 4.5 years; range, 2-6 years).

RESULTS

The initial curve Cobb angle of 64° (range, 38°-92°) improved to 21° (range, 4°-36°) and was maintained at 22° (range, 4°-36°) throughout followup. Preoperative thoracic kyphosis of 22° (range, 18°-46°) was maintained at 23° (range, 20°-39°) throughout followup without showing any substantial change. There was a 47 mm (range, 38-72 mm) increase in T1-S1 height throughout followup. The mean number of lengthening operations was 5.5 (range, 4-10). The mean T1-S1 length gain from the first lengthening was 1.18 cm (range, 1.03-2.24 cm) and decreased to 0.46 cm (range, 0,33-1.1 cm) after the fifth lengthening procedure (p = 0.009). The overall complication rate was 25% (four of 16 patients) and the procedural complication rate was 7% (seven of 102 procedures). We did not experience any rod breakages or other complications apart from two superficial wound infections managed without surgery during the treatment period. The only implant-related complications were loosening of two pedicle screws at the uppermost foundation in one patient.

CONCLUSIONS

In this preliminary study, the modified growing rod technique with apical and intermediate anchors provided satisfactory curve control, prevented progression, maintained rotational stability, and allowed continuation of trunk growth with a low implant-related complication rate.

Do Thoracolumbar/lumbar Curves Respond Differently to Growing Rod Surgery Compared With Thoracic Curves?

STUDY DESIGN

Retrospective study.

OBJECTIVES

To compare radiographic outcomes between primary thoracic and primary thoracolumbar/lumbar curves in patients with early-onset scoliosis (EOS) after growing rod (GR) surgery.

SUMMARY OF BACKGROUND DATA

Previous studies have shown the efficacy of GR surgery for progressive EOS. However, there is no information on the behavior of different curve patterns in EOS after GR surgery.

METHODS

A multicenter international EOS database query identified 175 patients who met the following inclusion criteria: non-congenital etiology, GR surgery, ≤ 10 years of age at index surgery, minimum 2-year follow-up, and at least 3 lengthenings. Patients were categorized into 2 groups based on the Scoliosis Research Society definition of the anatomical location of primary curves: group 1 included thoracic apices (T2 to T11/12 disc) and group 2 included thoracolumbar (T12 to L1) and lumbar (L1/2 disc to L4) apices. Radiographic measurements were performed before and after index surgery and at latest follow-up.

RESULTS

A total of 139 patients (79%) had primary thoracic (group 1) and 36 (21%) had primary thoracolumbar or lumbar curves (group 2). Mean number of levels instrumented was statistically greater in group 2 (15.0) versus group 1 (13.6) (p < .05). Group 2 had statistically better mean curve correction than group 1 after the index GR surgery (51% and 44%, respectively; p < .05). However, there was no significant difference in mean percent curve correction at latest follow-up (46% and 39%, respectively; p > .05). Implant complication rate was 45% and 47% for groups 1 and 2, respectively. Preoperative curve flexibility was greater in group 2 (45%) compared with group 1 (40%) (p > .05).

CONCLUSIONS

Overall, thoracolumbar/lumbar and thoracic curves achieve similar major curve correction and have a similar complication profile.

Recent advances in the management of early onset scoliosis

As the undesired results of early spinal fusion have become apparent, "growth-friendly" management methods for early onset scoliosis have been increasing during recent years. Current literature supports the use of repeated corrective cast applications as the initial management for most early onset progressive spinal deformities as either definitive treatment or as a temporizing measure. If casting is not an option or the deformity cannot be controlled via casting, one of the growth-friendly instrumentation techniques is chosen. Growth-friendly surgical methods and implants have been evolving as understanding of the disease improves.

One-stage posterior osteotomy with short segmental fusion and dual growing rod technique for severe rigid congenital scoliosis: the preliminary clinical outcomes of a hybrid technique

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate the clinical outcomes of the hybrid technique of 1-stage posterior osteotomy with short segmental fusion and dual growing rod (GR) technique for severe rigid congenital scoliosis.

SUMMARY OF BACKGROUND DATA

As some types of congenital scoliosis consist of long curve including sharp deformities producing enormous asymmetric growth at apex, they cannot be well corrected with osteotomy and short segmental fusion. GR technique may be the best option. However, enormous asymmetric growth potential due to the sharp deformities at the apex will increase risk of complications, especially implant failures.

METHODS

Seven patients (2 males, 5 females) undergoing this hybrid technique for severe rigid congenital scoliosis were retrospectively reviewed. The patients' charts were reviewed. The analysis included age at initial surgery and the latest follow-up, number and frequency of lengthening, and complications. Radiographical evaluation included measured changes in scoliosis Cobb angle, thoracic kyphosis, lumbar lordosis, trunk shift, length of T1-S1, and instrumentation.

RESULTS

The mean follow-up was 53.3 (30-77) months. The mean age at the initial surgery is 5.9 (2-10) years. The averaged lengthenings were of 5.3 per patient. The mean scoliosis improved from 81.4° to 40.1° after initial surgery and was 41.0° at the latest follow-up. The average T1-S1 length was of 1.23 cm per year. The space available for lung ratio increased from 0.86 to 0.96.

CONCLUSION

Osteotomy with short fusion could help to improve the correction of the GR and eliminate the large asymmetric growth potential around the apex, with little influence to the length of the spine. Dual GR technique could maintain correction achieved at initial surgery while allowing spinal growth to continue. This hybrid technique may be an option for young patients who present sharp deformities with large asymmetric growth potential in a long congenital spinal deformity.

LEVEL OF EVIDENCE

4.

Proximal Junctional Kyphosis After Vertical Expandable Prosthetic Titanium Rib Insertion

STUDY DESIGN

Retrospective review of patients who had undergone vertical expandable prosthetic titanium rib (VEPTR) treatment at a single institution.

OBJECTIVES

To evaluate whether clinically significant proximal junctional kyphosis (PJK) occurs after VEPTR insertion.

SUMMARY OF BACKGROUND DATA

PJK is a potential problem after posterior spinal instrumentation and fusion. PJK after VEPTR insertion has not been well-described.

METHODS

A total of 68 patients underwent VEPTR treatment between 1999 and 2009. Diagnosis, age at time of VEPTR insertion, location of VEPTR anchors, preoperative and postoperative scoliosis, T2-T12 kyphosis and PJK, time from VEPTR insertion to development of PJK, revision procedure for significant PJK, change in PJK after the revision procedure, and PJK at final follow-up were recorded.

RESULTS

Four patients developed PJK (6%). One patient had congenital scoliosis with rib fusions, 1 had scoliosis associated with a syndrome, and 2 had neuromuscular scoliosis. Mean follow-up was 5.7 years. Average T2-T12 kyphosis and PJK before VEPTR insertion were 77° and 14°, respectively. Mean T2-T12 kyphosis and PJK after VEPTR insertion were 63° and 33°, respectively. Average T2-T12 kyphosis and PJK before the recommended revision procedure for treatment of PJK were 89° and 53°, respectively. All patients developed PJK within the first year after VEPTR insertion. Two patients underwent revision to growing rods. One of these patients had preoperative halo-gravity traction. Mean PJK in these 2 patients improved from 39° to 18° after revision and remained stable at 19° at an average follow-up of 2.9 years.

CONCLUSIONS

PJK after VEPTR insertion can occur. Patients with preoperative thoracic hyperkyphosis may be at higher risk. PJK can develop within the first year of VEPTR treatment, and can become progressive and severe enough to require complex interventions. In this small case series, patients were revised to growing rods.

Growing-rod graduates: lessons learned from ninety-nine patients who completed lengthening

BACKGROUND

Growing-rod spinal instrumentation systems are a valuable tool for managing severe early-onset scoliosis. There is little information about the end point of treatment.

METHODS

A multicenter early-onset-scoliosis database was searched to identify patients who had undergone treatment with growing rods and either had had a final operative procedure or were still being treated with the growing rods after reaching skeletal maturity (defined as fourteen years of age or older). Clinical, radiographic, and operative data were analyzed.

RESULTS

Ninety-nine patients met the inclusion criteria, and ninety-two (93%) of them had had a final operative procedure. The remaining seven patients (7%) were older than fourteen years but had not undergone a final procedure. Of the ninety-two patients who had a final procedure, seventy-nine (86%) had an instrumented fusion, nine (10%) had growing-rod exchanges and fusion in situ, three (3%) had the growing rods left in place and fusion in situ, and one (1%) had only growing-rod removal. The mean age (and standard deviation) at the final fusion was 12.4 ± 1.9 years. In forty-four (55%) of eighty patients for whom the information was available, the number of vertebral levels fused was the same as the number of vertebral levels spanned by the growing rods. The percent correction of the curve after final fusion was none or minimal (≤ 20 %) in eleven (18%) of the sixty-two patients for whom sufficient-quality radiographs were available, moderate (21% to 50%) in thirty (48%), and substantial (≥ 51 %) in nine (15%); the curve had worsened in twelve patients (19%). The mean duration of growing-rod treatment was 5.0 ± 2.6 years. Of fifty-eight operative reports made at final fusion that contained comments on spinal flexibility, eleven (19%) described the spine as being mobile, eleven (19%) described decreased flexibility, and thirty-six (62%) described the spine as being completely stiff. At final fusion, twenty-two patients (24%) had osteotomies and seven patients (8%) had a thoracoplasty.

CONCLUSIONS

Most patients underwent growing-rod removal and final instrumented fusion. The final fusion often included the same levels spanned by the growing rods and usually achieved <50% additional correction of the deformity remaining at the end of the growing-rod management.

LEVEL OF EVIDENCE

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

Dual growing rods technique for congenital scoliosis: more than 2 years outcomes: preliminary results of a single center

STUDY DESIGN

Retrospective study.

OBJECTIVE

To evaluate clinical outcomes of dual growing rod (GR) technique in treating children with congenital scoliosis (CS).

SUMMARY OF BACKGROUND DATA

Published reports on the dual GR technique results of early-onset scoliosis demonstrate it to be safe and effective. However, the use of GR in congenital spinal deformities is controversial, and there have been no reports on the results and complications of dual GR technique for CS with large series of patients.

METHODS

During 2004 to 2009, a total of 30 patients with CS underwent dual GR procedures. Of the 159 total procedures conducted within the treatment period, 125 were lengthenings with an average of 4.2 lengthenings per patient. Five patients with severe rigid deformity or kyphosis had an osteotomy at apex vertebra with short segmental fusion. The analysis included age at initial surgery and final fusion (if applicable), number and frequency of lengthenings, and complications. Radiographical evaluation was conducted.

RESULTS

The mean scoliosis improved from 72.3° to 34.9° after initial surgery and was 35.2° at the last follow-up or after final fusion. T1-S1 length increased from 25.42 to 29.03 cm after initial surgery and to 33.32 cm at last follow-up or after final fusion with an average T1-S1 length increase of 1.49 cm per year. The space available for lung ratio in patients with thoracic curves improved from 0.84 to 0.96 at the latest follow-up. Three patients reached final fusion. Complications occurred in 7 of the 30 patients, and they had a total of 13 complications.

CONCLUSION

The dual GR technique is safe and effective in the treatment of selected cases of long, complex CS. It maintains correction achieved at initial surgery while allowing spinal growth to continue. And it has an acceptable rate of complications. The osteotomy at the apex vertebra with short segmental fusion of the severe rigid scoliosis or the patients with kyphosis could help to improve the correction and decrease the implant failures, with little influence on the length of the spine.

H3S2 (3 hooks, 2 screws) construct: a simple growing rod technique for early onset scoliosis

PURPOSE

The purpose of this study was to review the preliminary results of an original fusionless method of treatment for progressive scoliosis in young children.

METHODS

This study retrospectively reviewed the clinical records and radiographs of 23 children with progressive scoliosis who failed to respond to conservative treatment and underwent fusionless surgery using a single solid growing rod construct. All of them were ambulatory and had a follow-up of minimum 2 years. Sixteen patients were treated by consecutive distraction of a single intramuscular rod, and seven patients with rodding and anterior apical convex fusion. The etiology of the scoliosis included 11 idiopathic, 6 syndromic, 4 congenital, and 2 neurofibromatosis. At initial surgery, the average age was 9.3 ± 2.8 years, with a mean Cobb angle of 68° ± 32°. Six patients underwent progressive scoliosis correction in a Stagnara cast prior to surgery, and one patient with an external halo-pelvic Ilizarov device.

RESULTS

Fusionless single rodding allowed to maintain scoliosis correction in all patients. At an average of 3.5 ± 0.9 years after initial surgery, the 23 patients showed a correction of 57 % in the magnitude of the original curvature. Trunk height increase was documented in all patients and ranged from 1.5 to 11.9 cm. Rod failure was found in three patients and two patients had hardware infection. Only four cases of proximal junctional kyphosis were found at last follow-up.

CONCLUSIONS

Preliminary results from these series of patients show that the presented fusionless single growing rod technique allows to maintain correction of progressive early onset scoliosis while permitting spinal growth, with low complication rate. With this technique, lengthening procedures are used only once in every 10 months and patients are more comfortable as no brace is needed in most cases. This technique does not require any specific spine device. The procedure is simple and efficacious as long as some guidelines are respected.

In vivo distraction force and length measurements of growing rods: which factors influence the ability to lengthen?

STUDY DESIGN

Prospective, intraoperative force measurement in consecutive lengthening procedures in a series of growing-rod patients undergoing lengthening.

OBJECTIVE

The purpose of this study was to measure the forces and amount of distraction over time in early onset scoliosis patients treated with growing rods.

SUMMARY OF BACKGROUND DATA

Growing rods are one of the current techniques used in the treatment of early onset scoliosis, and the goal of the growing-rod technique is to achieve deformity correction, maintaining spinal growth at the same time. Gradual stiffening or spontaneous fusion of the spine can interfere with the ability to lengthen. In addition, diminished acquired length with serial distraction are common observations and need to be evaluated and quantified.

METHODS

Distraction forces were measured prospectively during 60 consecutive lengthening procedures in 26 patients. All patients had single submuscular rod constructs with side-to-side connectors. For each measurement, output from a transducer on a dedicated pair of distraction calipers was recorded at zero load status and the force was then recorded at every 1 mm lengthening; length was obtained at each event and was recorded in millimeters.

RESULTS

The force required to distract the spine doubled at the 5th lengthening procedure (mean 368 N ± 54 N), and the distraction force was significantly higher at the fifth lengthening compared with the previous lengthening (P <0.01). Mean length achieved at each distraction decreased over time such that by the fifth lengthening, consistently 8 mm or less was achieved.

CONCLUSION

Distraction forces increase significantly after repeated lengthening of growing-rod constructs, and the length obtained at each procedure exhibits a decreasing trend.

Growing rod fractures: risk factors and opportunities for prevention

STUDY DESIGN

Review of a prospectively collected growing rod database.

OBJECTIVE

To define risk factors for and characterize the nature of growing rod fractures.

SUMMARY OF BACKGROUND DATA

Rod fracture is a common complication of growing rod treatment. The project sought to analyze risk factors for rod breakage and develop preventive strategies.

METHODS

Records of 327 patients in a prospectively collected growing rod database were studied. Risk factors studied were studied as patient-related and rod-related. Multivariate analysis was performed.

RESULTS

Eighty-six rod fractures occurred in 49 patients (49 of 327, 15%). Sixteen patients had repeat fractures with eight patients having more than two fractures (maximum six). The most common fracture locations were above or below the tandem connectors (34 of 86) and near the thoracolumbar junction (35 of 86). Other locations were adjacent to anchors (12 of 86) and cross-links (2 of 86). Syndromic diagnoses had the highest rate of fracture; significantly greater than neuromuscular diagnoses (14% vs. 2%, P = 0.01). Patients who were ambulatory had a higher fracture rate (21% vs. 8.7%, P = 0.01). Single rods had a higher fracture rate than dual rods (36% vs. 11%, P < 0.001). Repeat fracture was also more common in patients with single rods (13% vs. 2%, P = 0.0002). In dual-rod constructs, the incidence of both rods breaking at the same time was 26% (7 of 27). Stainless steel rods had a higher fracture rate than titanium rods (29% vs. 18%, P = 0.02). The nonfracture group had larger diameter rods than the fracture group (P = 0.01). The fracture group had shorter tandem connectors than the nonfracture group (P < 0.001). Neither the size of preoperative scoliosis (P = 0.2) nor kyphosis (P = 0.4) was a risk factor for fracture. Length of instrumentation (P = 0.9), anchor type (P = 0.6), and pelvic fixation (P = 0.38) had no significant effect on fracture rates. Eight wound complications were reported, including three cases of skin breakdown at the rod fracture site.

CONCLUSION

Risk factors for rod fractures include prior fracture, single rods, stainless steel rods, small diameter rods, proximity to tandem connectors, short tandem connectors, and preoperative ambulation. Repeat fractures are common, especially with single rods. Rod replacement, with larger diameter rods if appropriate, may be a preferred strategy over connecting the broken rods as fractures signal fatigue of the rod.

Fusionless procedures for the management of early-onset spine deformities in 2011: what do we know?

While attempts to understand them better and treat them more effectively, early-onset deformities have gained great pace in the past few years. Large patient series with long follow-ups that would provide high levels of evidence are still almost non-existent. That there is no safe treatment algorithm defined and agreed upon for this patient population continues to pose a challenge for pediatric spine surgeons. In this review, authors who are well known for their research and experience in the treatment of early-onset scoliosis (EOS) have come together in order to answer those questions which are most frequently asked by other surgeons. The most basic eight questions in this field have been answered succinctly by these authors and a current overview is provided.

VEPTR™ growing rods for early-onset neuromuscular scoliosis: feasible and effective

BACKGROUND

The Vertical Expandable Prosthetic Titanium Rib (VEPTR™; Synthes North America, West Chester, PA) reportedly controls spinal deformity associated with constrictive chest wall conditions.

QUESTIONS/PURPOSES

We asked whether spine-to-spine constructs using VEPTR™ instrumentation in combination with standard spinal instrumentation could be deployed to salvage failed rib-to-spine constructs used originally in patients with constricted chest walls and to primarily treat progressive spinal deformity without chest wall abnormalities.

PATIENTS AND METHODS

Fifty patients were treated with VEPTR™ constructs for thoracic insufficiency syndrome at our center between 2001 and 2007. Fourteen of these 50 patients had placement of a spine-to-spine construct using a VEPTR™ implant in combination with standard spinal implants and are the subject of this retrospective review. Five had prior rib-based VEPTR™ or growing implants with an average of two failures before this surgery. Radiographic variables, preceding treatment, complications, and changes in ambulatory status, were recorded. The minimum followup was 2 years (mean, 35 months; range, 2-4 years).

RESULTS

After an average of five expansions in these 14 patients, positive changes were recorded for Cobb angle, T1-S1 height, sagittal balance, and space available for the lung. Complications included two rod fractures, two superficial infections, and one deep infection with rod removal.

CONCLUSIONS

VEPTR™ instrumentation as a spine-to-spine growing-rod construct demonstrated ease of implantation and expansion, with complication rates similar to other reported devices. This study suggests growing constructs using VEPTR™ can be used with relatively few complications and extends the potential uses of this instrumentation system.

Variability of expert opinion in treatment of early-onset scoliosis

BACKGROUND

In contrast with treatment recommendations for adolescent idiopathic scoliosis, there are no clear algorithms for treating patients with early-onset scoliosis. There has been rapid expansion of treatment options for children with early-onset scoliosis, including casting, growth rods, the vertical expandable prosthetic titanium rib, and anterior vertebral stapling.

QUESTIONS/PURPOSES

Given the range of treatment options, we assessed variability in decision making regarding treatment of patients with early-onset scoliosis.

METHODS

We presented 12 clinical and radiographic vignettes about patients with early-onset scoliosis to 13 experienced spine surgeons who are members of the Chest Wall and Spine Deformity Study Group. The reviewers were asked to choose type of treatment, type of construct, construct location, and whether a thoracotomy should be performed.

RESULTS

All 13 surgeons agreed regarding the need for surgery in eight of the 12 cases. When the reviewers chose surgery, 76% (40%-100%) selected the vertical expandable prosthetic titanium rib; of those selecting that approach, 61% (0%-100%) coincided on using it bilaterally. Agreement was 20% (0%-60%) for growing rods and 4% (0%-25%) for fusions. Among all cases, agreement regarding whether instrumentation should extend to the pelvis was 71% (50%-100%). In all but two cases, at least 85% of surgeons recommended against a thoracotomy.

CONCLUSIONS

Although most surgeons agreed about the indication for surgery, we found wide variability in choice of construct type, number of constructs, and level of instrumentation.

Safety and efficacy of growing rod technique for pediatric congenital spinal deformities

BACKGROUND

Growing rod surgery is a modern alternative treatment for young children with early onset scoliosis. This is the first study focused on its use in progressive congenital spinal deformities.

METHODS

A retrospective study of 19 patients from the international multicenter Growing Spine Study Group with progressive congenital spinal deformities undergoing growing rod surgery who had a minimum of 2 years follow-up. We analyzed demographic and radiographic data including age at initial surgery, number of abnormal vertebrae per patient, number of lengthenings postoperatively, Cobb angle of the major curve preoperative, postoperative initial and at last follow-up, T1-S1 length, space available for the lung (SAL), length of follow up, and complications.

RESULTS

The mean age at surgery was 6.9 years (range: 3.2 to 10.7 y). The mean number of affected vertebrae per patient was 5.2 (range: 2 to 9 vertebrae). The mean number of lengthening was 4.2 (range: 1 to 10 lengthening) per patient. The major Cobb angle improved from 66 degrees (range: 40 to 95 degrees) preoperatively to 45 degrees (range: 13 to 79 degrees) initial postoperative and 47 degrees (range: 18 to 78 degrees) at the last follow-up. The mean T1-S1 length increased from 268.3 mm (range: 192 to 322 mm) postoperatively to a mean of 315.4 mm (range: 261 to 357 mm) at last follow-up. The mean T1-S1 length increase was 11.7 mm/y. The SAL ratio increased from 0.81 preoperatively to 0.94 at latest follow-up. The mean postoperative follow-up was 4 years (range: 2 to 6.6 y). Five patients (38%) had undergone final fusion and 14 are still under treatment. Complications have occurred in 8 patients (42%). There were 14 (14%) complications in 100 procedures: 11 implant related, 2 pulmonary, and 1 postoperative infection. There were no neurological complications.

CONCLUSIONS

Growing rods are a safe and effective treatment technique in selected patients with congenital spinal deformities. The deformity, spinal growth, and the SAL improved. The incidence of complication was relatively low.

LEVEL OF EVIDENCE

Level IV, case series.

Minimizing complications with single submuscular growing rods: a review of technique and results on 88 patients with minimum two-year follow-up

STUDY DESIGN

Retrospective clinical and radiologic review of consecutive series of patients treated with single submuscular growing rods from a single center with a minimum of 2-year follow-up.

OBJECTIVES

To describe the surgical technique and methods used to minimize complications and to report on the outcomes of a large consecutive series of patients treated with single submuscular growing rods for scoliosis in the immature spine from a single center.

SUMMARY OF BACKGROUND DATA

Previous studies have reported on the safety and efficacy of single and dual growing-rod constructs; however, these studies have been of small patient numbers with varying results.

METHODS

Between 1999 and 2007, 88 patients underwent the insertion of a single, submuscular growing-rod construct for scoliosis. A clinical and radiologic review of these 88 consecutive patients with a minimum of 2-year follow-up was conducted. Diagnoses include idiopathic, neuromuscular, syndromic, and congenital. Data include Cobb angle measurements, T1-S1 heights, number, and frequency of lengthening as well as complications.

RESULTS

The patients underwent single submuscular growing-rod insertion at an average age of 7.0 years. The mean follow-up period was 42 months. Twenty-eight patients had a simultaneous apical fusion. Growing-rod lengthening was performed on an average at 9-month intervals. The average initial Cobb angle was 73° (range: 40-117) and improved to 44° (range: 9-90) at final follow-up. T1-S1 height gain was 3.37 cm; this translates to 1.04 cm growth/yr. No significant difference was noted between those who had undergone apical fusion and those without. Complications noted in this series include 8 incidences of superficial infection and 3 of deep infection, proximal junctional kyphosis in 2 patients requiring early fusion, 31 rod fractures, 10 cases of proximal anchor failure, and 6 distal anchor failures. Thirty patients within study group have reached definitive fusion.

CONCLUSION

Favorable outcomes have been demonstrated in this large single-center series of growing-rod constructs used to treat scoliosis in the growing spine. Their safety and efficacy in controlling spinal deformity and allowing spinal growth along with an acceptable rate of complications would support the continued use of single growing-rod constructs as a scoliosis management option.

Growing rods for spinal deformity: characterizing consensus and variation in current use

SUMMARY OF BACKGROUND DATA

Growing rods are a commonly used form of growth guidance for patients with early onset scoliosis, but no studies exist to characterize their use among a large group of surgeons.

METHODS

A survey regarding growing rod use preferences and a case-based survey regarding early onset scoliosis were completed by an international group of surgeons. Two hundred and sixty-five growing rod patients treated over 4.7+/-2.1 years in the Growing Spine Study Group database were analyzed to characterize actual practice and compare it with the survey results. All patients had at least 2 years of treatment.

RESULTS

In the case-based survey, there was correlation (P=0.04, r=0.58) between increasing curve size and choice of growing rods over nonoperative treatment, rib-based distraction (vertically expandable prosthetic titanium rib), growth guidance (Shilla), and primary fusion. In practice, growing rods were used for most types of early onset spine deformity. Most surgeons stated that their indication for growing rod treatment was a curve over 60 degrees (10/13) in a patient younger than 8 to 10 years (14/17). In practice, mean curve at rod insertion was 73+/-20 degrees and age was 6.0+/-2.5 years. Other factors favoring growing rods included curve rigidity (8/17), brace intolerance (6/17) and syndromic diagnoses (2/17). In the database, idiopathic scoliosis represented <50% of diagnoses. The most common preferred surgical lengthening interval was 6 months. However, in practice, lengthening actually occurred at a mean of 8.6+/-5.1 months. In the database, the number of growing rod insertions per year (P=0.02, r=0.96) and percentage of surgeons using dual rods over single rods (P=0.065, r=0.93) increased over time. Insertion age (P=0.075, r=-0.87) and lengthening interval (P=0.006, r=-0.69) decreased as time progressed. The most common stated indication on the survey for final fusion was skeletal maturity (13/17), and 7/13 surgeons used Risser 3 or more. Indications to stop lengthening included complications such as infection or implant failure (14/17), curves progressing past 90 degrees (8/17), and failure to distract (6/13). The most common method of final fusion was replacement of implants with more intermediate anchors.

CONCLUSIONS

Significant practice variation exists in growing rod treatment, but there is some consensus on indications for surgery including curve size, diagnosis and age, and lengthening intervals and final fusion methods. Mean curve size and lengthening interval are greater in practice than in surgeons' stated aims. In principle and in practice, most growing rods are used for curves over 60 degrees in patients under 10, in all diagnoses. This information may form a starting point as practice variation is studied.

Current concepts in the management of early-onset idiopathic scoliosis

Early-onset scoliosis is a diagnosis when a child is presenting with scoliosis before the age of 5 years. This excludes other causes of scoliosis (e.g., congenital, neuromuscular or syndromic). Twin studies and observations of familial aggregation reveal significant genetic contributions to idiopathic scoliosis. Radiographic criteria help in distinguishing the progressive curves from those that will resolve spontaneously. One must do a complete clinical evaluation to exclude other organ involvement especially congenital heart disease, inguinal hernia and hip dysplasia. MRI scans of the neural axis are mandatory in curves greater than 20° at presentation to rule out any occult lesions in the CNS. Minor nonprogressive curves can be managed with observation until growth is completed. Some curves may be managed with casting and bracing. There is increased risk of morbidity and mortality due to respiratory failure in untreated children with early-onset scoliosis who have progressive curves. Therefore, progressive curves must be addressed surgically. Surgical procedures continue to evolve and are primarily directed at correcting and maintaining the curve correction while simultaneously preserving spinal and trunk growth. A definitive spinal fusion is indicated once the thoracic spinal growth is nearing completion.

Three-dimensional stereoradiographic modeling of rib cage before and after spinal growing rod procedures in early-onset scoliosis

BACKGROUND

Early-onset scoliosis frequently leads to major thoracic deformity and pulmonary restrictive disease. Growing rods surgical techniques were developed to achieve a satisfactory correction of the spinal curves during growth. The effect on the rib cage deformity has not yet been documented. The purpose of this study was to analyze the changes of the thoracic geometry after implantation of a growing rod, and to evaluate a stereoradiographic reconstruction method among young scoliotic patients.

METHODS

Four patients were enrolled in the study, and four additional patients in the reproducibility study. Three-dimensional spine and rib cage models were generated after low-dose stereoradiographic imaging (EOS). Three-dimensional parameters were computed before and after surgery. Intra and inter-observer reproducibility was calculated, and the accuracy was assessed in comparison to volumetric CT-scan.

FINDINGS

The average Cobb angle was reduced from 50.8 degrees to 26 degrees . The surgery resulted in a complex 3D effect on the rib cage, combining frontal, lateral, and axial rotation. This effect was dependent of the side (concave or convex), and the position relative to the apical vertebra. Mean errors in comparison to CT-scan were 3.5mm.

INTERPRETATION

The results on the spinal deformity are comparable to other series. The effect on the rib cage is of a smaller magnitude than in the case of a spinal arthrodesis. A longer follow-up is necessary to confirm the positive effect on the rib cage deformity. Further research should be performed to improve the reproducibility of 3D parameters.

Shilla growing rods in a caprine animal model: a pilot study

There are few good surgical options that allow for continued spinal growth in patients with early-onset scoliosis. The "Shilla" is a growth guidance system that does not require repeated surgical lengthenings. The Shilla system guides growth at the ends of dual rods with the apex of the curve corrected, fused, and fixed to the rods. The growth occurs through the extraperiosteally implanted pedicle screws that slide along the rods at either end of the construct. We implanted 11 2-month-old immature goats with the dual rod system and euthanized all 11 goats 6 months postoperatively. We evaluated plain radiographs, regular computed tomography, microcomputed tomography, physical and histologic examinations, and a microscopic wear analysis. All of the goat spines grew with the implants in place; growth occurred in both the thoracic and lumbar ends of the rods for a total average of 48 mm. None of the implants failed, although we observed minor wear at the rod/screw interface. Growth guidance with the Shilla rod system allowed for continued growth in this goat model.

Thoracic malformation with early-onset scoliosis: effect of serial VEPTR expansion thoracoplasty on lung growth and function in children

The effect on pulmonary function of serial VEPTR expansion thoracoplasty was studied longitudinally in anesthetized children with spondylothoracic dysplasia using a special mobile unit. The median age of 24 children at the start of surgery was 4.6 years (1.8-10.8) and most exhibited a moderate-to-severe restrictive lung defect. After a median of 3.2 years (1.0-6.5), their forced vital capacity (FVC) was found to have increased by an average of 11.1%/year. The rate of increase was greater in children who were younger than 6 years at the start of the study than in older children (14.5% versus 6.5%, p<0.01). The average specific respiratory system compliance (C(rs)) was mildly-to-moderately decreased at the start, and over the study it decreased on average to 56% of the initial value in spite of clinically successful expansion thoracoplasty and lung growth, indicating increasing stiffness of the thorax with growth.

Biomechanical comparison of different anchors (foundations) for the pediatric dual growing rod technique

BACKGROUND CONTEXT

Children with early onset scoliosis benefit from early operative treatment with dual growing rods as they provide an "internal brace" for the spine and allow curve correction and sequential lengthenings to maximize thoracic cage development. The foundations that provide anchor points for the dual growing rods may incorporate hooks, screws, or a hybrid construct. It is unclear how stable different types of foundation constructs are with regard to pullout.

PURPOSE

This study was to determine the differences in stability between four foundation configurations used in the pediatric dual growing rod technique. Eight porcine spines were sectioned and randomly assigned to one of four foundation groups: 1) hook-hook with cross-link; 2) hook-screw with cross-link; 3) screw-screw with cross-link; and 4) screw-screw without cross-link. After instrumentation, biomechanical pullout tests were conducted. Ultimate failure loads, modes of failure, and level of instrumentation were analyzed.

STUDY DESIGN/SETTING

Controlled in vitro laboratory investigation.

RESULTS

Screw-screw with cross-link constructs demonstrated the greatest failure load but this was not statistically significant compared with the screw-screw without cross-link constructs. Both screw-screw constructs were statistically stronger than either construct containing hooks. There was no difference between the hook-screw and hook-hook constructs that was statistically significant. Hook-containing constructs sustained higher failure loads in lumbar versus thoracic vertebrae.

CONCLUSIONS

A foundation composed of four pedicle screws implanted in two adjacent vertebral bodies provides the strongest construct in pullout testing. A cross-link does not seem to enhance fixation. Hook constructs are stronger in lumbar versus thoracic laminae.

PRINCIPLES OF GROWTH MODULATION IN THE TREATMENT OF SCOLIOTIC DEFORMITIES

INTRAOPERATIVE MANIPULATION TO correct scoliotic deformities relies upon spinal instrumentation for stabilization and fusion. However, novel strategies and innovative implant biotechnologies have emerged, applying natural growth and elongation of the immature spine for the treatment of scoliosis in young patients. In this work, we review the principles of growth modulation and the Hueter-Volkmann law as it applies to experimental models of scoliosis formation and correction. Current implant technologies, including shape memory alloy vertebral staples, growing rods, and vertical expandable titanium prosthetic ribs, are explored, with regards to implant design, surgical techniques, and clinical investigations. An exciting area of spinal implant technology is now becoming available to expand the surgical armamentarium for treating severe scoliotic deformity in young patients.

DECISION MAKING IN PEDIATRIC SPINAL DEFORMITY

OBJECTIVE

To review the concepts involved in the decision-making process for management of pediatric patients with spinal deformity.

METHODS

The literature was reviewed in reference to pediatric deformity evaluation and management.

RESULTS

Pediatric spinal deformity includes a broad range of disorders with differing causes, natural histories, and treatments. Appropriate categorization of pediatric deformities is an important first step in the clinical decision-making process. An understanding of both nonoperative and operative treatment modalities and their indications is requisite to providing treatment for pediatric patients with spinal deformity. The primary nonoperative treatment modalities include bracing and casting, and the primary operative treatments include nonfusion instrumentation and fusion with or without instrumentation. In this article, we provide a review of pediatric spinal deformity classification and an overview of general treatment principles.

CONCLUSION

The decision-making process in pediatric deformity begins with appropriate diagnosis and classification of the deformity. Treatment decisions, both nonoperative and operative, are often predicated on the basis of the age of the patient and the natural history of the disorder.

A century of spine surgery: what can patients expect?

PURPOSE

To evaluate the hypothesis that spinal fusion surgery is an effective method to address spinal deformity-associated clinical problems, including magnitude of curvature (Cobb angle), pulmonary dysfunction, and pain.

METHOD

A systematic review was carried out using Science Citation Index (SCI) Expanded (1900 - present), Social Sciences Citation Index (1956 - present), Arts and Humanities Citation Index (1965 - present), Medline (1950 - present) and PubMed Central databases (1887 - present) to access information regarding efficacy of spine surgery in preventing or improving the health and function of patients diagnosed with scoliosis in adolescence.

RESULTS

Since 1950, more than 12,600 articles on scoliosis have been published, and nearly 50% (5721) focus on methods, rationale, outcome, and complications of surgical intervention. Among these, 82 articles have documented outcome for groups of > or =10 patients, treated for adolescent idiopathic scoliosis, and followed for at least 2 years after treatment. These data provide an overview of the impact of spine surgery on scoliosis for 5780 patients as surgery methods and approaches have evolved.

CONCLUSIONS

For most patients, a reduced magnitude of spinal curvature can be achieved through one or more spinal fusion surgeries. There is no evidence to support the premise that this result is correlated with improved pulmonary function or reduced pain.

Dual growing rod technique followed for three to eleven years until final fusion: the effect of frequency of lengthening

STUDY DESIGN

Retrospective case review of children completing dual growing rod treatment at our institutions. Patients had a minimum of 2 years follow-up.

OBJECTIVE

To identify the factors influencing dual growing rod treatment outcome followed to final fusion.

SUMMARY OF BACKGROUND DATA

Published reports on dual growing rod technique results for early onset scoliosis demonstrate it to be safe and effective in curve correction and maintenance as well as in allowing spinal growth.

METHODS

Between 1990 and 2003, 13 patients with no previous surgery and noncongenital curves underwent final fusion. All had preoperative curve progression over 10 degrees after unsuccessful nonoperative treatment. There were 10 females and 3 males. Average age was 6.6 +/- 2.9 years at initial surgery. There were 3 idiopathic, 1 nonspine congenital anomaly, and 9 syndromic patients. Analysis included age at initial surgery and final fusion, number and frequency of lengthenings, and complications. Radiographic evaluation included changes in Cobb angle, T1-S1 length, and instrumentation length over the treatment period.

RESULTS

Cobb angle improved from 81.0 +/- 23 degrees to 35.8 +/- 15 degrees postinitial and 27.7 +/- 17 degrees after final fusion. Average number of lengthenings was 5.2 +/- 3 at an interval of 9.4 +/- 5 months. T1-S1 length increased from 24.4 +/- 3.4 to 29.3 +/- 3.6 cm postinitial and 35.0 +/- 3.7 cm postfinal fusion. Average growth was 1.46 +/- 0.66 cm/year. Those lengthened at <or=6 months (n = 7; range, 5.5-6.7 months) had a higher annual growth rate of 1.8 cm versus 1.0 cm (P = 0.018) from postinitial to postfinal and significantly greater scoliosis correction (79% vs. 48%, P = 0.007) than those lengthened less frequently (n = 6; range, 9-20 months). Six patients experienced complications: 3 within the treatment period, 2 postfinal, and 1 both during and after treatment.

CONCLUSION

Dual growing rod technique resulted in 5.7 +/- 2.9 cm of spinal growth during a 4.37 +/- 2.4 year treatment period. There was significantly greater growth and correction achieved in those lengthened more frequently.

Surgical treatment of congenital scoliosis

The surgical options for congenital spine deformities are numerous and depend on the type of anomaly, the degree of deformity, and the age of the patient. The mainstay of surgical treatment remains early diagnosis before severe curvature and deformity exist. Occasionally, patients present with large deformities that require more significant procedures; however, early limited arthrodesis remains the safest and most reliable procedure. Patients who have significant decompensation of the spine at a young age may benefit from a fusionless procedure, as do patients who have coexisting rib deformities and chest wall insufficiency. This article reviews the general surgical principles that need to be followed to treat these patients safely. The numerous surgical procedures available for treating these patients also are reviewed.