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Steven W. Hwang, Amer F. Samdani and Patrick J. Cahill

Object

Idiopathic scoliosis is a pathological process influencing the spinal column in 3 dimensions. Initial surgical treatment focused primarily on correction in the coronal plane, and with improved instrumentation, increasing attention has targeted balancing the sagittal profile. Newer surgical techniques now permit operative corrective forces to also directly address axial rotation. Although several technical variations of direct vertebral body derotation (DVBD) have been devised, no studies have compared outcomes from the differing techniques. The purpose of this study was to describe and compare the differences between segmental and en bloc DVBD.

Methods

A large prospectively collected database was queried for patients with adolescent idiopathic scoliosis (AIS) who underwent posterior spinal fusion and for whom there was a minimum of 2 years of follow-up. In all patients some type of DVBD maneuver was performed (segmental, en bloc, or both). Any patients with concurrent thoracoplasties were excluded.

Results

The authors identified 188 patients, of whom 120 underwent segmental derotation, 17 en bloc derotation, and 51 both. No significant radiographic or clinical differences existed among the groups preoperatively. The mean preoperative thoracic curve in the entire cohort was 53.1° ± 14.1° and the mean thoracic rib prominence was 14.0° ± 5.5°, whereas the respective postoperative values were 19.3° ± 8.3° and 7.2° ± 4.0°. No significant difference was identified between the various techniques postoperatively, either. However, when comparing intraoperative variables, significant differences were found for operative duration (p = 0.0001), estimated blood loss (p = 0.0081), and volume of blood transfusions (p = 0.041).

Conclusions

Although each surgical technique of DBVD may have theoretical benefits and risks, no apparent difference in outcomes was observed between techniques. The concurrent use of both techniques was associated with increased blood loss and operative duration without any appreciable benefit. The surgeon should adopt the derotation technique with which he or she is most comfortable, but concurrent use of both does not appear to improve results.

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Thomas L. Slamovits, Kenneth V. Cahill, Patrick A. Sibony, Andrew Dekker and Bruce L. Johnson

✓ The authors report their experience with five patients presenting with cavernous sinus syndrome who, on computerized tomography (CT) studies, were shown to have a lesion simultaneously involving the cavernous sinus and a portion of the orbit. All patients underwent an orbital fine-needle aspiration biopsy (FNAB). A specific cytological diagnosis was made in three of the five patients. To obtain pathological diagnosis in the case of cavernous sinus tumors, invasive diagnostic procedures are sometimes necessary. Extension of lesions from the cavernous sinus into adjacent areas should be carefully looked for on CT scans. In the specific subset of patients with cavernous sinus tumors and simultaneous orbital involvement, orbital FNAB may provide a simple alternative to more invasive procedures. The limitations of the procedure are discussed.

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Jason R. Smith, Amer F. Samdani, Joshua Pahys, Ashish Ranade, Jahangir Asghar, Patrick Cahill and Randal R. Betz

Object

There are few data on treatment results for patients with idiopathic infantile scoliosis (IIS). Thus, the authors have performed a retrospective review of their experience with treating these patients, particularly as newer technologies, such as the vertical expandable prosthetic titanium rib (VEPTR), emerge.

Methods

This retrospective study was conducted to evaluate the methods of treatment used to manage IIS at a single institution. The authors reviewed 31 consecutive patients with a primary diagnosis of IIS. Patients were screened to ensure that there were no confounding congenital anomalies or comorbidities that may have contributed to the spinal deformity. The average age at the time of initial treatment was 25 months. Treatment modalities included bracing, serial body casting, and VEPTR. Pretreatment, posttreatment, and most recent Cobb angles were compared to assess the overall curve correction, and patient charts were reviewed for the occurrence of complications.

Results

Of the 31 patients, 17 were treated with a brace, 9 of whom had curve progression and went on to other forms of treatment. Of the 8 who did respond, there was an overall improvement of 51.2%. The 10 patients who received body casts, who had a mean preoperative Cobb angle of 50.4°, demonstrated an average correction of 59.0%, with only a few skin irritations reported. The 10 patients treated with VEPTR devices demonstrated a mean preoperative Cobb angle of 90.0°, and an average correction of 33.8% was attained. Three of the VEPTR-treated patients (33%) experienced minor problems.

Conclusions

The authors' results suggest that body casting has utility for appropriately selected patients; that is, those with smaller, flexible spinal curves. Bracing had limited utility, with high levels of progression and the need for secondary treatments. The VEPTR device appears to be a viable alternative for large-magnitude curves.

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Steven W. Hwang, Mina G. Safain, Joseph J. King, Jeff S. Kimball, Robert Ames, Randall R. Betz, Patrick J. Cahill and Amer F. Samdani

OBJECT

Almost all pediatric patients who incur a spinal cord injury (SCI) will develop scoliosis, and younger patients are at highest risk for curve progression requiring surgical intervention. Although the use of pedicle screws is increasing in popularity, their impact on SCI-related scoliosis has not been described. The authors retrospectively reviewed the radiographic outcomes of pedicle screw–only constructs in all patients who had undergone SCI-related scoliosis correction at a single institution.

Methods

Medical records and radiographs from Shriner's Hospital for Children–Philadelphia for the period between November 2004 and February 2011 were retrospectively reviewed.

Results

Thirty-seven patients, whose mean age at the index surgery was 14.91 ± 3.29 years, were identified. The cohort had a mean follow-up of 33.2 ± 22.8 months. The mean preoperative coronal Cobb angle was 65.5° ± 25.7°, which corrected to 20.3° ± 14.4°, translating into a 69% correction (p < 0.05). The preoperative coronal balance was 24.4 ± 22.6 mm, with a postoperative measurement of 21.6 ± 20.7 mm (p = 1.00). Preoperative pelvic obliquity was 12.7° ± 8.7°, which corrected to 4.1° ± 3.8°, translating into a 68% correction (p < 0.05). Preoperative shoulder balance, as measured by the clavicle angle, was 8.2° ± 8.4°, which corrected to 2.7° ± 3.1° (67% correction, p < 0.05). Preoperatively, thoracic kyphosis measured 44.2° ± 23.7° and was 33.8° ± 11.5° postoperatively. Thoracolumbar kyphosis was 18.7° ± 12.1° preoperatively, reduced to 8.1° ± 7.7° postoperatively, and measured 26.8° ± 20.2° at the last follow-up (p < 0.05). Preoperatively, lumbar lordosis was 35.3° ± 22.0°, which remained stable at 35.6° ± 15.0° postoperatively.

Conclusions

Pedicle screw constructs appear to provide better correction of coronal parameters than historically reported and provide significant improvement of sagittal kyphosis as well. Although pedicle screws appear to provide good radiographic results, correlation with clinical outcomes is necessary to determine the true impact of pedicle screw constructs on SCI-related scoliosis correction.

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Amer F. Samdani, Ashish Ranade, Henry J. Dolch, Reed Williams, Tricia St. Hilaire, Patrick Cahill and Randal R. Betz

Object

Few options exist for the treatment of severe, early onset scoliosis. Goals of treatment include stabilizing curve progression while allowing for normal spine, chest, and lung growth. The vertical expandable prosthetic titanium rib (VEPTR) is a novel device designed to control the spine deformity while permitting lung and spine growth. In this paper the authors report their experience with using bilateral VEPTRs from the ribs to the pelvis for children with severe, early onset scoliosis.

Methods

Eleven children were identified who had been treated with bilateral VEPTRs from the ribs to the pelvis. The authors conducted a retrospective review and collected the following data: clinical diagnosis, age at surgery, number of lengthening procedures, and complications. In addition, pre- and postoperative radiographs were reviewed to measure maximum Cobb angle (both thoracic and lumbar), thoracic height, total spine height as measured from T-1 to S-1, thoracic kyphosis (T2–12), and lumbar lordosis (L1–S1).

Results

The average patient age at surgery was 71 months; the mean preoperative thoracic Cobb angle was 81.7°. This angle was corrected to 50.6° immediately postoperatively, and this correction was maintained; at the most recent follow-up the curves averaged 58°. Similarly, the preoperative kyphosis (T2–12) angle measured 43° preoperatively, 23° immediately postoperatively, and 37° at the most recent follow-up evaluation. The patients underwent a total of 41 lengthening procedures (average 3.7 lengthening procedures per patient), and overall spine length increased from 23.1 cm preoperatively, to 27.3 cm immediately postoperatively, to 29.4 cm at the final follow-up (an average of 25 months). Four (36.4%) of the 11 patients experienced complications.

Conclusions

The VEPTR offers a viable treatment option for children with severe, early onset scoliosis. It achieves and maintains spinal deformity correction, while allowing for continued spine and chest-wall growth. Complication rates are similar to those reported for other growing systems.

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Steven W. Hwang, Amer F. Samdani, Baron S. Lonner, Michelle C. Marks, Tracey P. Bastrom, Randal R. Betz and Patrick J. Cahill

Object

In the surgical management of adolescent idiopathic scoliosis (AIS), patients are often preoperatively informed that they will gain height as a result of their surgery. However, current estimations conflict significantly and do not have any clinical correlation. The authors developed a formula that would predict postoperative gains in height after deformity correction in AIS.

Methods

A large, multicenter, prospective database was retrospectively queried for AIS patients with Lenke Type 1, 2, or 3 curves having undergone posterior spinal fusion alone. A univariate and multivariate analysis was performed to identify which factors contributed significantly to changes in height.

Results

Four hundred forty-seven patients were included in the series. Factors correlating with changes in postoperative height included: upper thoracic curve magnitude, main thoracic curve magnitude, lumbar curve magnitude, T2–12 kyphosis, T5–12 kyphosis, curve flexibility, number of levels fused, presence of Ponte osteotomies, total preoperative coronal Cobb angle, change in coronal curve magnitude, total preoperative sagittal curvature, change in sagittal curvature, and thoracic curve correction.

When combined in a multivariate regression analysis the following variables remained significant: thoracic curve magnitude (p < 0.01), number of levels fused (p < 0.01), change in total sagittal curvature (p < 0.01), and the presence of osteotomies (p = 0.03). The contribution from the thoracic curve magnitude was significantly greater than any of the other parameters identified (R2 = 0.140). Change in height (in cm) = ([thoracic curve magnitude × 0.039] + [number of levels fused × 0.193] − [change in sagittal curvature × 0.033] + [x × 0.375]) − 1.858, where x = 1 if 1 or more osteotomies were performed and x = 0 if no osteotomy was performed.

Conclusions

The authors' results suggest that changes in the coronal plane contribute more significantly to height changes than those in the sagittal plane and approximately 0.39 cm of height gain can be expected for each 10° of coronal curve preoperatively. Unfortunately, a significant fraction of the postoperative height changes cannot be predicted by currently measured parameters.

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Steven W. Hwang, Amer F. Samdani, Mark Tantorski, Patrick Cahill, Jason Nydick, Anthony Fine, Randal R. Betz and M. Darryl Antonacci

Object

Several studies have characterized the relationship among postoperative thoracic, lumbar, and pelvic alignment in the sagittal plane. However, little is known of the relationship between postoperative thoracic kyphosis and sagittal cervical alignment in patients with adolescent idiopathic scoliosis (AIS) treated with all pedicle screw constructs. The authors examined this relationship and associated factors.

Methods

A prospective database of pediatric patients with AIS undergoing spinal fusion between 2003 and 2005 was reviewed for those who received predominantly pedicle screw constructs for Lenke Type 1 or Type 2 curves. Parameters analyzed on pre- and postoperative radiographs were the fusion levels; cervical, thoracic, and lumbar sagittal balance; and C-2 and C-7 plumb lines.

Results

Preoperatively, 6 (Group A) of the 22 patients included in the study had frank cervical kyphosis (mean angle 13.0°) with mean associated thoracic kyphosis of 27.2° (range 16°–37°). Postoperatively, cervical kyphosis (13.0°) remained in the patients in Group A along with mean thoracic kyphosis of 17.7° (range 4°–26°, p < 0.05). Preoperatively, the remaining 16 of 22 patients had neutral to lordotic cervical alignment (mean −13.8°) with thoracic kyphosis (mean 45°, range 30°–76°). Postoperatively, 8 (Group B) of these 16 patients demonstrated cervical sagittal decompensation (> 5° kyphosis), with 6 showing frank cervical kyphosis (10.5°, p < 0.05). In Group B, the mean postoperative thoracic kyphosis was 25.6° (range 7°–49°, p < 0.05). The other 8 patients (Group C) had mean postoperative thoracic kyphosis of 44.1° (range 32°–65°), and there was no cervical decompensation (p < 0.05).

Conclusions

The sagittal profile of the thoracic spine is related to that of the cervical spine. The surgical treatment of Lenke Type 1 and 2 curves by using all pedicle screw constructs has a significant hypokyphotic effect on thoracic sagittal plane alignment (19 [86%] of 22 patients). If postoperative thoracic kyphosis is excessively decreased (mean 25.6°, p < 0.05), the cervical spine may decompensate into significant kyphosis.

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Steven W. Hwang, Amer F. Samdani, Ben Wormser, Hari Amin, Jeff S. Kimball, Robert J. Ames, Alexander S. Rothkrug and Patrick J. Cahill

Object

Pedicle screw fixation has been theorized to provide better correction of scoliotic deformity, but controversy over the benefits of pedicle screw–only constructs remains, and the longer-term impact of pedicle screw fixation as compared with hybrid constructs is unclear. In this study, a retrospective review of a prospectively collected database was conducted to determine the longer-term impact of pedicle screw fixation as compared with hybrid constructs in patients with adolescent idiopathic scoliosis (AIS).

Methods

The authors retrospectively reviewed a multicenter database of pediatric patients (ages ≤ 18) from 1995 to 2006 and identified 127 patients with Lenke Type 1–4 AIS curves with a minimum 5 years of follow-up. Patients were divided into 2 cohorts based on whether they had undergone pedicle screw fixation or fixation with hybrid constructs.

Results

The mean main thoracic curvature of 56.1° ± 13.0°, which corrected to 14.9° ± 9.3°, translated into a mean correction of 73% (p < 0.01). The curve was 19.4° ± 10.6° at 2-year follow-up and 20.5° ± 10.4° at 5 years. When comparing preoperative parameters between the groups, differences were noted in the magnitude of the main thoracic curve (p = 0.04), flexibility of the main thoracic curve (p = 0.02), coronal balance (p = 0.04), T2–12 kyphosis (p = 0.02), and sex (p = 0.02). The pedicle screw cohort had fewer spinal segments instrumented (p < 0.01), fewer anterior releases performed (p = 0.02), and fewer thoracoplasties performed (p < 0.01). By 5 years of follow-up, significant differences were apparent between the two cohorts with respect to upper thoracic curvature (p = 0.01), T2–12 (p = 0.02) and T5–12 (p = 0.02) kyphosis, lumbar lordosis (p < 0.01), and sagittal balance (p = 0.01).

Conclusions

Although some preoperative differences did exist, outcomes were comparable between hybrid and screw constructs at 2 and 5 years. However, hybrid constructs required more concurrent anterior releases and thoracoplasties to achieve similar results.

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Amer F. Samdani, Anthony L. Fine, Sukhdeep S. Sagoo, Shailja C. Shah, Patrick J. Cahill, David H. Clements and Randal R. Betz

Object

Tethering of the spinal cord is thought to increase the chance of neurological injury when scoliosis correction is undertaken. All patients with myelomeningocele (MM) are radiographically tethered, and untethering procedures carry significant morbidity risks including worsening neurological function and wound complications. No guidelines exist as regards untethering in patients with MM prior to scoliosis correction surgery. The authors' aim in this study was to evaluate their experience in patients with MM who were not untethered before scoliosis correction.

Methods

Seventeen patients with MM were retrospectively identified and 1) had no evidence of a clinically symptomatic tethered cord, 2) had undergone spinal fusion for scoliosis correction, and 3) had not been untethered for at least 1 year prior to surgery. The minimum follow-up after fusion was 2 years. Charts and radiographs were reviewed for neurological or shunt complications in the perioperative period.

Results

The average age of the patients was 12.4 years, and the following neurological levels were affected: T-12 and above, 7 patients; L-1/L-2, 6 patients; L-3, 2 patients; and L-4, 2 patients. All were radiographically tethered as confirmed on MR imaging. Fourteen of the patients (82%) had a ventriculoperitoneal shunt. The mean Cobb angle was corrected from 82° to 35°, for a 57% correction. All patients underwent neuromonitoring of their upper extremities, and some underwent lower extremity monitoring as well. Postoperatively, no patient experienced a new cranial nerve palsy, shunt malfunction, change in urological function, or upper extremity weakness/sensory loss. One patient had transient lower extremity weakness, which returned to baseline within 1 month of surgery.

Conclusions

The study results suggested that spinal cord untethering may be unnecessary in patients with MM who are undergoing scoliosis corrective surgery and do not present with clinical symptoms of a tethered cord, even though tethering is radiographically demonstrated.

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Charles E. Mackel, Patrick J. Cahill, Marie Roguski, Amer F. Samdani, Patrick A. Sugrue, Noriaki Kawakami, Peter F. Sturm, Joshua M. Pahys, Randal R. Betz, Ron El-Hawary and Steven W. Hwang

OBJECTIVE

The authors performed a study to identify clinical characteristics of pediatric patients diagnosed with Chiari I malformation and scoliosis associated with a need for spinal fusion after posterior fossa decompression when managing the scoliotic curve.

METHODS

The authors conducted a multicenter retrospective review of 44 patients, aged 18 years or younger, diagnosed with Chiari I malformation and scoliosis who underwent posterior fossa decompression from 2000 to 2010. The outcome of interest was the need for spinal fusion after decompression.

RESULTS

Overall, 18 patients (40%) underwent posterior fossa decompression alone, and 26 patients (60%) required a spinal fusion after the decompression. The mean Cobb angle at presentation and the proportion of patients with curves > 35° differed between the decompression-only and fusion cohorts (30.7° ± 11.8° vs 52.1° ± 26.3°, p = 0.002; 5 of 18 vs 17 of 26, p = 0.031). An odds ratio of 1.0625 favoring a need for fusion was established for each 1° of increase in Cobb angle (p = 0.012, OR 1.0625, 95% CI 1.0135–1.1138). Among the 14 patients older than 10 years of age with a primary Cobb angle exceeding 35°, 13 (93%) ultimately required fusion. Patients with at least 1 year of follow-up whose curves progressed more 10° after decompression were younger than those without curve progression (6.1 ± 3.0 years vs 13.7 ± 3.2 years, p = 0.001, Mann-Whitney U-test). Left apical thoracic curves constituted a higher proportion of curves in the decompression-only group (8 of 16 vs 1 of 21, p = 0.002).

CONCLUSIONS

The need for fusion after posterior fossa decompression reflected the curve severity at clinical presentation. Patients presenting with curves measuring > 35°, as well as those greater than 10 years of age, may be at greater risk for requiring fusion after posterior fossa decompression, while patients less than 10 years of age may require routine monitoring for curve progression. Left apical thoracic curves may have a better response to Chiari malformation decompression.