Victor Hsu and Behrooz Akbarnia
DEFINITION
Early-onset scoliosis (EOS) is defined by the diagnosis of scoliosis at or before the age of 5 years.
The many etiologies of EOS include:
Congenital vertebral or spinal anomalies: eg, vertebral bars, hemivertebrae, syrinx, tethered cord
Neuromuscular diseases: eg, cerebral palsy, spinal dysraphism, muscular dystrophy
Syndromes associated with scoliosis: eg, neurofibromatosis
Idiopathic causes
Age of onset is an important aspect of pathology, because progressive curves can be associated with growth disturbances as well as cardiopulmonary compromise, including restrictive lung disease and pulmonary hypertension.
ANATOMY
Two periods of increased growth velocity are associated with increased incidence of curve progression. The first occurs from birth to 5 years of age; the second includes the adolescent growth spurt occurring after age 10 until just before skeletal maturity.
The growth velocity from T1 to L5 is greatest from birth until the age of 5. Increases in height during this period average 2 cm per year, and by the age of 5, two thirds of the final sitting height is achieved. The years between 5 and 10 years of age exhibit much less growth. Finally, the adolescent growth spurt causes another increase in growth velocity, at a slower rate than the first growth spurt.
The increased spinal growth during the first years of life is paralleled by an increase in thorax and lung dimension. Thoracic volume at birth is about 5% of the adult volume; by 5 years of age, it equals 30% of adult volume. A slower rate of thoracic growth occurs from 5 to 10 years of age, by which time it has reached 50% of the adult volume. The final 50% of adult volume is achieved during the adolescent growth spurt from 10 to 15 years of age.
Lung development also occurs rapidly during the first year of life, and by age 8, most alveolar growth and respiratory branching has occurred.
PATHOGENESIS
The pathogenesis of EOS depends on its etiology. Vertebral anomalies cause scoliosis by an imbalance in bone growth, whether an increase on a side associated with a hemivertebrae, or retardation on the side associated with a vertebral bar. In neuromuscular and central nervous disorders, an imbalance in muscular forces is the pathogenesis, likely following the Heuter-Volkmann principle.
The etiology and pathogenesis of infantile idiopathic scoliosis (IIS) (0–3 years of age) is, by definition, unknown. There probably is a genetic component that provides a susceptibility to develop scoliosis. The external factors needed to produce the scoliosis are not yet clearly delineated but may include intrauterine molding as well as infant positioning. The etiology of IIS most likely differs from that of adolescent idiopathic scoliosis (AIS).
NATURAL HISTORY
The natural history also depends on the etiology. The natural history of EOS due to IIS is favorable when compared with late-onset scoliosis (LOS). Spontaneous resolution occurs in a large number of patients. Progression of congenital curves depends on the type of anomaly and growth potential. EOS due to neuromuscular etiologies usually follows the natural history of the disease in addition to specific problems associated with progressive curves in this age group.
Regardless of the etiology, progression of scoliosis during the first 5 years of life adversely affects growth as well as pulmonary function. Scoliosis inhibits the growth of both the alveoli and the pulmonary arterioles, causing ventilation defects. The scoliotic spine does not distort the architecture of the alveoli; rather, the total number is decreased significantly and is directly proportional to the age of onset. The earlier the onset of scoliosis, the more hypoplastic the lung is, with a diminution of alveoli greater than would be expected from just a lack of space.
Patients with EOS also may suffer from a restrictive pattern of pulmonary dysfunction. Lung compliance is reduced, with an associated decrease in total lung capacity as well as vital capacity. In contrast to patients with LOS, the severity of scoliosis in EOS is proportional to the severity of restrictive disease. The restrictive lung disease causes hypoventilation and vasoconstriction of the pulmonary tree and leads to pulmonary hypertension. EOS is associated with a higher risk of cardiopulmonary decompensation in middle-aged patients, which can lead to disabling and even fatal respiratory failure.
PATIENT HISTORY AND PHYSICAL FINDINGS
Evaluation of the patient with EOS includes a complete history, including the family history, prenatal history, birth history, and developmental history. IIS has been associated with breech presentation and, in boys, with premature birth. Curve progression also has been correlated with cognitive delay, so it is important to ask parents about the achievement of developmental milestones.
The physical examination of EOS heavily relies on the perceptive capabilities of the clinician and is the same examination that is performed on all scoliosis patients. After a careful history has already been obtained, a thorough physical examination, including inspection, palpation, motor testing, sensory testing, and reflex testing is necessary.
Inspection includes observation of gait, respiration, truncal and pelvic balance in the coronal and sagittal planes, cutaneous lesions, and any prominence on forward bending. Any deficits in motor, sensory, or reflex function, including abdominal reflexes, may indicate central nervous system pathology and should be thoroughly evaluated with advanced diagnostic studies.
Flexibility of the curve can be assessed either by the manual application of traction through the cervical spine or by applying a three-point bending force at the apex of the curve. Examination techniques unique for early-onset scoliosis include the thumb excursion test for thoracic expansion and sitting height measurement.
IMAGING AND OTHER DIAGNOSTIC STUDIES
All patients should have full-length standing anteroposterior (AP) and lateral radiographs (FIG 1A,B) covering the cervical spine to the pelvis, including the entire thorax. For patients who are unable to stand, supine radiographs encompassing the same area should be taken.
The cervical spine, lumbosacral spine, pelvis, and hips all may need to be studied to elicit whether or not developmental hip dysplasia or other vertebral anomalies are contributing to the scoliosis.
Side-bending or traction radiographs are necessary to help delineate the degree of flexibility of the curves.
Similar to LOS evaluation, the Cobb technique is used to measure any curve by measuring the angle created by a line through the superior endplate of the most cranial vertebra and a line through the inferiormost point of the most caudal endplate. This should be done in both the coronal and sagittal planes and compared to normal values. These angles can be used to measure progression of the curve with successive visits but are subject to a small amount of user error variability between 5 to 6 degrees.
Spinal height is obtained by measuring the distance from the top of T1 to the top of S1 on the AP view of the spine (FIG 1C).
Coronal balance is measured by the distance from the center of C7 to a line drawn up from S1.
The sagittal balance is measured from the posterior-cranial corner of S1 to a line drawn down from the center of C7.
All of these measurements should be recorded and compared on successive visits to document any change in curve magnitude or growth of the spine.
The rib-vertebral angle difference of Mehta (RVAD; FIG 2), first described in 1972, measures the amount of rotation at the apex vertebra and has some prognostic value.6
The angles formed by a line perpendicular to the vertebra and a line drawn down the center of the rib is compared between the convex and concave side. If the difference calculated by subtracting the convex angle to the concave angle is 20 degrees or less, there is an 85% to 90% chance the curve will resolve; when there is a difference of 21 degrees or more it will likely progress.
The phase of the rib head also is described by ascertaining whether the head of the convex rib overlaps the vertebral body.
If there is no overlap (phase 1), then the RVAD is calculated as previously mentioned.
If there is overlap (phase 2), the risk of progression is high, regardless of RVAD.
Another method of evaluating rotation is the Nash-Moe method (FIG 3). Evaluating the pedicles of the apical vertebra at the convexity, the distance of the pedicle on the convex side is measured.
Zero: the pedicles are equidistant from the sides
Grade 1: the concave pedicle is partially obscured, and the convex pedicle moves away from the edge toward the center
Grade 3: the convex pedicle is in the midline of the vertebral body.
Grade 2: between grades 1 and 3
Grade 4: the convex pedicle lies past the midline.
FIG 1 • A. Lateral radiograph of a neuromuscular patient with early-onset scoliosis. B. AP radiograph with space available for the lung (SAL) of a patient with early-onset scoliosis. C. Measurement of vertebral height from T1 to S1.
FIG 2 • The rib-vertebral angle difference (RVAD) measures the angle of a line drawn perpendicular to the apical thoracic vertebra endplate and a line drawn down the center of the concave and convex ribs. The difference is calculated by subtracting the convex from the concave angle. An RVAD of 20 degrees or less indicates a curve that is likely to resolve; an RVAD of 21 degrees or greater often is associated with curves that will progress. The phase of the rib head notes the position of the convex rib head on the apical vertebra. A “phase 1” relationship indicates no overlap of the rib head or neck on the apical vertebra. In cases that have a phase 1 relationship, the RVAD may be calculated and used to determine the likelihood of progression. In a phase 2 relationship, the head of the rib on the convex side of the apical vertebra overlaps with the vertebra, and the curve is likely to progress. (Adapted from Mehta MH. The rib-vertebra angle in the early diagnosis between resolving and progressive infantile scoliosis. J Bone Joint Surg Br 1972;54B:230–243.)
The space available for the lung (SAL) is calculated by taking the ratio of the distance from the apex of the most cephalad rib to the highest point of the hemidiaphragm of the concave side divided by the convex side (see Fig 1B).
Any decrease in the SAL points toward a poorer prognosis for lung function.
MRI allows the best visualization of the central nervous system and is indicated in EOS associated with neurologic abnormalities or curve greater than 20 degrees.
CT scanning with 3-D reconstructions is helpful to delineate bony architecture and is warranted when plain radiographs do not provide enough information and for preoperative planning for patients who have vertebral abnormalities (eg, dysplastic pedicles or hemivertebrae).
The CT scan or MRI is also used to measure lung volume and assess thoracic architecture when thoracic insufficiency is an issue. It often is difficult to assess these parameters with plain radiographs, but CT allows better visualization of each hemithorax and measurement of the lung volume.
In severe congenital deformity, the ribs may spiral around the vertebrae, causing the thoracic volume on one side to be severely diminished while the other is larger, creating what Campbell calls a “windswept thorax” (FIG 4).
FIG 3 • Measurements performed on apical vertebra. If the pedicles are equidistant from the sides, rotation is classified as zero. If the concave pedicle is partially obscured and the convex pedicle moves away from the edge toward the center, that is considered grade 1. Grade 3 is defined as the convex pedicle in the midline of the vertebral body. Grade 2 lies between grades 1 and 3. Grade 4 indicates that the convex pedicle lies past midline. (Adapted from Nash CL Jr, Moe JH. A study of vertebral rotation. J Bone Joint Surg Am 1969;51A:223–229.)
DIFFERENTIAL DIAGNOSIS
Congenital vertebral or spinal anomalies
Vertebral bars
Hemivertebrae
Syrinx
Tethered cord
FIG 4 • CT scan of the chest showing decreased lung volumes due to scoliosis.
Neuromuscular diseases
Cerebral palsy
Myelodysplasia
Muscular dystrophy
Syndromes associated with scoliosis
Beel syndrome
Trisomies
Infantile idiopathic scoliosis
NONOPERATIVE MANAGEMENT
Nonoperative treatment for EOS is indicated in curves that are not expected to progress or that are expected to progress only mildly, taking into consideration the etiology of the curve and the radiographic parameters described by Mehta6 in cases with IIS.
Patients with a curve less than 25 degrees and RVAD less than 20 degrees may be followed with serial radiographs every 4 to 6 months to document any progression.
Active treatment is warranted in:
Progression greater than 10 degrees; treatment starts with casting and bracing.
Phase 2 rib-vertebral relationship, RVAD greater than 20 degrees, or a Cobb angle greater than 20 degrees in any skeletally immature patient
Progression of more than 5 degrees in a patient with a Cobb angle greater than 35 degrees
Casting usually is done under anesthesia. The cast is changed every 6 to 12 weeks until the ultimate correction is achieved.
After casting, a Milwaukee brace (FIG 5) is used for 23 hours a day to help maintain the correction. Fully circumferential braces may distort the rib cage and adversely affect pulmonary status, because the immature thoracic wall may deform before any correction of the spine occurs.
Bracing is continued for a minimum of 2 years until the Cobb angle and RVAD are stable.
The goal is to correct the deformity completely before the prepubertal growth spurt.
FIG 5 • The Milwaukee brace consists of metal rods attached to pads at the hips, rib cage, and neck.
Nonoperative treatment for neuromuscular or congenital scoliosis can be attempted for curves of lesser magnitudes. Treatment options available include casting and bracing.
Bracing is less effective for these types of deformities than for idiopathic scoliosis, but can be used in long flexible curves.
Deformities with large sagittal components are not amenable to brace treatment.
Brace treatment for congenital or neuromuscular scoliosis should be abandoned when unacceptable curve magnitude or progression is seen.
SURGICAL MANAGEMENT
Surgical treatment of EOS attempts to stop progression of the scoliosis, allowing improvements in growth of the spine, thorax, and lungs.
Surgery is recommended for progressive curves greater than 45 degrees.
The age of the patient helps to decide the type of surgery needed.
Adolescents and more skeletally mature patients may do well with spine fusions, which stabilize the spine but also stop growth.
Younger patients with substantial growth potential suffer from the “crankshaft” phenomenon if fusion is performed early in life from an isolated posterior approach. They suffer from severe growth retardation in height and thorax volume if fusion is performed using a combined anterior and posterior technique.
The growing rod technique for EOS was developed to correct spinal deformity while allowing spinal growth to continue or even enhancing that growth.
Preoperative Planning
Careful evaluation of radiographic studies allows planning of surgical levels. Typically, the cranial level of the construct includes T2 and extends two or three levels caudal to the end vertebra of the curve.
Either pedicle screws or hooks can be used in the construct. Review of the pedicle structure using radiographs and CT scans is necessary to be sure the desired implants are selected.
Medical and subspecialty consultations should be obtained before operation if the patient has any history of medical comorbidities.
Cardiopulmonary, renal, skeletal, and other neuromuscular defects often are associated with scoliosis.
Pulmonary function tests may be obtained in children who are able to cooperate if thoracic insufficiency is suspected.
Positioning
The patient is placed under general anesthesia on the stretcher and then placed on the operating room table in the prone position on two longitudinal chest rolls or tightly rolled blankets.
Neural monitoring is used during the procedure for neurologically intact patients. Leads should be placed before prone positioning, as should a Foley catheter.
Care must be taken to be sure all bony prominences and compressible nerves are well padded.
Approach
The growing rod technique is performed posteriorly through either a single long midline incision or two smaller incisions cranially and caudally.
TECHNIQUES
GROWING ROD INSTRUMENTATION FOR EARLY-ONSET SCOLIOSIS
Single-Incision Technique
Exposing the Foundations
The single-incision technique consists of a long superficial posterior incision beginning 2 to 3 cm cranial to the planned levels and ending caudal to the lowest vertebra by 2 to 3 cm. Infiltration of epinephrine may be used before subcutaneous incision.
The spinous processes of the cranial and caudal foundations are exposed and marked with a metallic object such as a Kocher clamp, and a lateral radiograph is then used to confirm the levels.
The foundations are critical to the construct in the dual growing rod technique.
They are composed of at least two pair of anchors and usually span two or three vertebral levels.
The foundations consist of the vertebral segments at either ends of the constructs, which are internally fixed with anchors.
Because the corrective loads are applied to these foundations, it is imperative that strong and stable constructs be achieved to decrease the incidence of implant or fixation failure.
Limited fusions of the foundation levels often are performed using local bone graft or allograft extenders to provide more stability.
The posterior elements of the cranial and caudal foundations are exposed subperiosteally out to the level of the transverse processes.
Vertebral levels not involved in a foundation should not be exposed, to decrease the chance of unwanted fusion.
Placing the Anchors
Once exposure has been obtained, the anchors are placed.
The foundations may be anchored using either pedicle screws or hooks.
If hooks are used, the superior edges of the most cranial lamina or transverse processes (TP) on either side are exposed, and supralaminar hooks or TP hooks are placed in a downgoing manner on both sides.
Contralateral supralaminar hooks may be staggered over two levels if canal stenosis is a concern.
Next, upgoing hooks are placed, usually under the facet articulations of the same vertebra but sometimes in a staggered arrangement.
Foundations using supralaminar hooks generally consist of three vertebral levels with supralaminar hooks placed on either side of the cranial two vertebra and the facet hooks placed on the most caudal one.
If TP hooks are used, only two vertebral levels are used, with the TP hooks placed on either side of the cranial vertebra and the facet hooks placed on the same cranial vertebra.
For more stability, additional facet hooks can be used to extend the foundation to three levels. It is important to achieve adequate stability at initial surgery.
Pedicle screws also may be used, usually with four screws spanning two vertebral levels. Pedicle screws may offer increased stability to the construct and are preferred for both foundations as long as the anatomy allows their safe placement.
Multiple methods for thoracic pedicle screw placement have been popularized. In general, the thoracic pedicle starting point is located at the intersection of the lateral border of the superior articular facet and the cranial aspect of the transverse process.
The trajectory of the thoracic pedicle screw generally travels lateral to medial about 30 degrees and from cranial to caudal 10 degrees, but varies by level (TECH FIG 1A–C).
Lumbar pedicle screws start at the junction of the pars interarticularis, the midpoint of the transverse process, and the base of the superior articular process.
Lumbar screw trajectory also varies, from about 10 degrees at L1 to 30 degrees at L5 from lateral to medial, and varies in the sagittal direction approximately 10 degrees from L1 to L5, depending on lordosis (TECH FIG 1D).
Fluoroscopy and neural monitoring are helpful in aiding pedicle screw placement, especially in patients with deformity. If needed, a combination of hooks and screws can be used.
Adding the Rods
The dual rod technique employs two rods, each made up of a cranial foundation rod and a caudal foundation rod joined by a connector, for a total of four rods for the entire construct.
Either of two types of connectors may be used: a tandem connector, which houses the cranial and caudal rods inside a rectangular box so the ends meet end to end, or side-to-side connectors, which allow the rods to overlap.
Tandem connectors usually are favored. Because they are straight and cannot be contoured, the rods are measured so that they meet inside the tandem connector in the relatively straight thoracolumbar region.
The ends of the rods that fit inside the connector also must be straight. If any contouring is necessary in the region where the cranial and caudal rods meet, closed dual connectors must be used, with an overlap of 2 to 4 inches to allow future lengthening.
Bilateral rods are prepared for each foundation by measuring the length of the spine in the corrected position and carefully contouring the rod. The concave side usually is constructed first to gain maximal correction.
The rods can be placed either subcutaneously or subfascially. Subfascial placement involves a much deeper dissection, both initially and with each lengthening, however, and may increase the risk of premature fusion. Subcutaneous placement may be associated with a higher incidence of skin problems and wound infection.
TECH FIG 1 • A. A single skin incision may be used with subperiosteal exposure of the cranial and caudal foundation sites. The rods and tandem connectors are placed above the fascia in this picture. Pedicle screws have been used as anchors. B. The lateral view shows the straight tandem connector placed in the thoracolumbar region. The trajectory of the pedicle screws can also be seen and varies between patients. C. Close-up of the cranial foundation shows four pedicle screws spanning two levels in the thoracic region. D. Close-up of the caudal foundation shows four pedicle screws spanning two levels in the lumbar spine. Hooks may also be used for either foundation. (From Akbarnia BA. Growing rod technique for the treatment of progressive early onset scoliosis in fusionless surgery for spine deformity. In: Kim DH, Betz R, Huhn SL, Newton PO, eds. Surgery of the Pediatric Spine. New York, Thieme, 2007:814.)
After the rods are placed in the hooks or screws of each foundation, transverse connectors are placed between the two cranial rods and the two caudal rods, preferably between the points of fixation on each foundation.
If the transverse connectors are close-holed, it may be necessary to preload them onto the rods before they are placed in the anchors, and the spinous processes may be removed to allow proper seating.
These transverse connectors increase the stability of the construct, especially when hooks have been used. There is less need for transverse connectors when screws are used.
The tandem connector is held with a rod holder and slid onto the cranial rod; once the caudal rod is cleared, it is slid onto the caudal rod.
The cranial anchors and transverse connector are tightened first, followed by the caudal anchors and transverse connectors. Cranial and caudal set screws are located on the side of the tandem connector that correlates to the most prominent side.
To create distraction, the caudal set screw is tightened, a distractor is implemented in the slot of the tandem connector between the two rods, and the cranial set screw is tightened (TECH FIG 2A).
Similarly, a rod clamp can be used to distract against if a closed dual connector is used or even on a tandem connector (TECH FIG 2B).
Next, the rod construct on the convex side of the curve is created similarly and tightened. The surgical area is then irrigated, followed by a limited arthrodesis applying autograft bone or other graft extenders between the vertebrae making up each foundation.
Before final closure, anteroposterior and lateral radiographs are taken to confirm alignment and proper position of the implants (TECH FIG 2C,D).
The wound is then closed in standard fashion.
Dual-Incision Technique
The dual-incision technique differs from the single-incision technique in a few ways.
The incisions are centered over the foundation sites with a long skin bridge between them (TECH FIG 3).
The subperiosteal dissection is the same, as are placement strategies of either hooks or pedicle screws for anchors.
In placing the rods, however, subcutaneous or subfascial dissection must be performed carefully and bluntly with either a finger or blunt clamp to facilitate rod passage.
Careless dissection or poor control of the rod during passage can lead to pleural violation.
The rods must be placed beneath the skin bridge and the tandem connector placed on the caudal rod before they are fitted into the anchors.
The rest of the procedure is similar to the single-incision technique.
Lengthening and Exchange
Lengthening of the dual rod construct may be performed as either an inor outpatient procedure with neural monitoring for patients with normal neurologic function.
The connector is located through palpation or fluoroscopy, and a small incision is made over that area where the lengthening is planned.
TECH FIG 2 • A. Lengthening may be performed by inserting the distractor between the rods through the slot of the tandem connector. One set screw is loosened, distraction is performed, and the set screw secured. B.Alternatively, a rod clamp can be placed on the rod a few centimeters from the connector and the distractor placed between the rod clamp and the end of the connector. The set screw nearest the rod clamp is then loosened, the distractor employed, and the screw retightened. C. AP radiograph after the dual growing rod procedure was performed on the patient shown in Figure 1B and C. D. Lateral radiograph after the dual growing rod procedure was performed on the same patient. (A,B: Bagheri R, Akbarnia BA. Pediatric Isola instrumentation. In: Kim DH, Vaccaro AR, Fessler RG, eds. Spinal Instrumentation: Surgical Techniques. New York: Thieme, 2005:640,642.)
After dissection of the connector is performed, lengthening similar to that performed during the index procedure is carried out by loosening the set screw (mostly cranial), distracting between the two rods, and then tightening the set screw again.
Lengthening is performed every 6 months.
Once further distraction is no longer achievable, final correction and arthrodesis are performed.
Changing the Connector or Rod
Exchange of the tandem connector or the rod may be needed if the amount of lengthening exceeds the initial length of the tandem connector.
TECH FIG 3 • The dual-incision technique employs two separate incisions centered over the foundations and separated by a skin bridge.
In such a case, both set screws should be loosened and the tandem connector slid cephalad until full clearance of the caudal rod is achieved.
The connector can then be removed off the cranial rod, replaced by a longer connector, and slid onto the caudal rod again.
Longer than 70 mm connector is rarely used, to minimize the adverse effect on sagittal balance.
If the needed length exceeds the longest connector or if the longest connector is too long, it is necessary to fashion new rods and remove the old ones.
This entails exposing and removing the tandem connectors, exposing the foundation, and removing the rods and replacing them with longer rods, creating a construct similar to the initial procedure.
Replacement of the cephalad rods is most common.
Final Fusion
Final fusion is performed near the end of the adolescent growth spurt or when the rods can no longer be lengthened.
The first step entails removing the dual growing rod implants, including the anchors and exploring foundations for solid fusions. One should be careful to cause the least trauma to the soft tissues.
For most patients, the fusion should extend from the cranial foundation to the cephalad foundation.
Either hooks or pedicle screws can be used in the foundations and at the apices of the curves.
Rods are then contoured to the desired shape, keeping in mind that the goal is to achieve global balance rather than a totally straight spinal segment. Thus, upper and lower curves should be considered together when contouring the rods.
A consideration when performing the final fusion is that posterior osteotomies may be required, especially if a subfascial technique is employed, because the posterior elements may become stiff after repeated exposures.
This usually can be done safely by finding the neural canal and then osteotomizing the pars on either side.
Another consideration is that the areas around the anchor sites often are overgrown with bone, and taking the implants out often entails osteotomizing the bone around the anchors.
Care should be taken to point away from the spinal canal to avoid neural injury.
Although pedicle screws offer three-column support in the foundations, replacing hooks in the fusion mass provides sufficient strength if placed properly, and hooks are easier to place, especially if they were used initially for the growing rods.
Sublaminar wires also offer an attractive option and are useful if lateral translation of the spine is required.
POSTOPERATIVE CARE
Patients are braced postoperatively with a thoracolumbosacral orthosis, beginning when they have been upright for up to 6 months and continuing until fusion of the foundations. Rehabilitation proceeds according to the patient's tolerance and ability.
OUTCOMES
Documented outcomes are short-term, and no level I studies are currently available.
One study showed Cobb angle correction from an average of 82 degrees to 36 degrees at last visit or final fusion.
Spine growth is almost equal to normal, averaging 1.21 cm/year.
Some patients averaged almost 12 cm of growth.
SAL increased from 0.87 to 1.
Better balance and cosmesis
COMPLICATIONS
Wound breakdown
Infection
Junctional kyphosis
Crankshaft phenomenon
Curve progression
Implant failure
Patients with more frequent lengthenings have fewer implant problems but more wound problems, whereas patients with less frequent lengthenings have more implant problems and fewer wound complications. Implant complications often can be treated during scheduled lengthenings, but wound infections should be treated urgently.
REFERENCES
· Akbarnia B. Management themes in early onset scoliosis. J Bone Joint Surg Am 2007;89 (Suppl 1):42–54.
· Akbarnia BA, Marks DS. Instrumentation with limited arthrodesis for the treatment of progressive early-onset scoliosis. Spine 2000;14: 181–189.
· Akbarnia B, Marks DS, Boachie-Adjei O, et al. Dual growing rod technique for the treatment of progressive early-onset scoliosis: a multicenter study. Spine 2005;30:46–57.
· Bagheri R, Akbarnia B. Pediatric isola instrumentation. In: Kim DH, Vaccaro AR, Fessler RG, eds. Spinal Instrumentation: Surgical Techniques. New York: Thieme, 2004:636–643.
· Gillingham B, et al. Early onset idiopathic scoliosis. J Am Acad Orthop Surg 2006;14:101–112.
· Mehta MH. The rib-vertebra angle in the early diagnosis between resolving and progressive infantile scoliosis. J Bone Joint Surg Br 1972;54B:230–243.
· Thomspson G, Akbarnia BA, Kostial P, et al. Comparison of single and dual growing rod techniques followed through definitive surgery: a preliminary study. Spine 2005;30:2039–2044.