Jahangir Asghar

Vertebral body stapling: a fusionless treatment option for a growing child with moderate idiopathic scoliosis.

Study Design. Retrospective review. Objective. To report the results of vertebral body stapling (VBS) with minimum 2-year follow-up in patients with idiopathic scoliosis. Summary of Background Data. While bracing for idiopathic scoliosis is moderately successful, its efficacy has been called into question, and it carries associated psychosocial ramifications. VBS has been shown to be a safe, feasible alternative to bracing for idiopathic scoliosis. Methods. We retrospectively reviewed 28 of 29 patients (96%) with idiopathic scoliosis treated with VBS followed for a minimum of 2 years. Inclusion criteria: Risser sign of 0 or 1 and coronal curve measuring between 20° and 45°. Results. There were 26 thoracic and 15 lumbar curves. Average follow-up was 3.2 years. The procedure was considered a success if curves corrected to within 10° of preoperative measurement or decreased >10°. Thoracic curves measuring <35° had a success rate of 77.7%. Curves which reached ≤20° on first erect radiograph had a success rate of 85.7%. Flexible curves >50% correction on bend film had a success rate of 71.4%. Of the 26 curves, 4 (15%) showed correction >10°. Kyphosis improved in 7 patients with preoperative hypokyphosis (<10° of kyphosis T5–T12). Of the patients, 83.5% had remaining normal thoracic kyphosis of 10° to 40°. Lumbar curves demonstrated a success rate of 86.7%. Four of the 15 lumbar curves (27%) showed correction >10°. Major complications include rupture of a unrecognized congenital diaphragmatic hernia and curve overcorrection in 1 patient. Two minor complications included superior mesenteric artery syndrome and atelectasis due to a mucous plug. There were no instances of staple dislodgement or neurovascular injury. Conclusion. Analysis of patients with idiopathic scoliosis (IS) with high-risk progression treated with vertebral body stapling (VBS) and minimum 2-year follow-up shows a success rate of 87% in all lumbar curves and in 79% of thoracic curves <35°. Thoracic curves >35° were not successful and require alternative treatments.

Autofusion in the immature spine treated with growing rods.

Study Design. Retrospective case review of skeletally immature patients treated with growing rods. Patients received an average of 9.6 years follow-up care. Objective. (1) to identify the rate of autofusion in the growing spine with the use of growing rods; (2) to quantify how much correction can be attained with definitive instrumented fusion after long-term treatment with growing rods; and (3) to describe the extent of Smith-Petersen osteotomies required to gain correction of an autofused spine following growing rod treatment. Summary of Background Data. The safety and use of growing rods for curve correction and maintenance in the growing spine population has been established in published reports. While autofusion has been reported, the prevalence and sequelae are not known. Methods. Nine skeletally immature children with scoliosis were identified who had been treated using growing rods. A retrospective review of the medical records and radiographs was conducted and the following data collected: complications, pre- and postoperative Cobb angles at time of initial surgery (growing rod placement), pre- and postoperative Cobb angles at time of final surgery (growing rod removal and definitive fusion), total spine length as measured from T1–S1, % correction since initiation of treatment and at definitive fusion, total number of surgeries, and number of patients found to have autofusion at the time of device removal. Results. The rate of autofusion in children treated with growing rods was 89%. The average percent of the Cobb angle correction obtained at definitive fusion was 44%. On average, 7 osteotomies per patient were required at the time of definitive fusion due to autofusion. Conclusion. Although growing rods have efficacy in the control of deformity within the growing spine, they also have adverse effects on the spine. Immature spines treated with a growing rod have high rates of unintended autofusion which can possibly lead to difficult and only moderate correction at the time of definitive fusion.

Computed Tomography Evaluation of Rotation Correction in Adolescent Idiopathic Scoliosis : A Comparison of an All Pedicle Screw Construct Versus a Hook-Rod System

Study Design. Retrospective review with historical cohort. Objective. Our study measures axial rotation of the apical vertebral bodies of patients with adolescent idiopathic scoliosis treated with an all pedicle screw (APS) construct versus a hook-rod (HR) construct using computed tomography (CT). Summary of Background Data. Ecker et al (Spine 1988;13:1141–4) observed a 22% derotation of the apical vertebrate of the thoracic spine and 33% of the apical vertebra of the lumbar spine when using an HR system (CD instrumentation). More recently Lee et al (Spine 2004;29:343–9) reported 42.5% derotation of the apical vertebra (both thoracic and lumbar) in a series of APS constructs. Currently, there is no comparison series reported between the 2 types of constructs. Methods. From a database of 193 patients with adolescent idiopathic scoliosis and posterior spinal fusions, 32 patients were identified as having all APS constructs with pre- and postoperative CT scans. This cohort of patients was compared with a historical published cohort of patients treated with HR constructs by Ecker et al (Spine 1988;13:1141–4) Comparison of the groups showed no statistically significant differences for age and preoperative Cobb angle of the main curve (P > 0.05); however, there was a statistically significant difference (P < 0.05) in postoperative correction values. The apical vertebral rotation for the major curve was measured from the pre- and postoperative axial CT using the methods described by Aaro and Dahlborn (Spine 1981;6:460–7). Result. The average preoperative rotation was similar between the 2 groups (thoracic: HR = 22.6, APS = 21.3, P = 0.6; lumbar: HR = 19.4, APS = 20.6, P = 0.7). The postoperative correction had a significant difference (thoracic: HR = 16, APS = 8.5, P = 0.015; lumbar: HR = 13.4, APS = 7.0, P = 0.032). The percent correction of the apical vertebrae showed a significant difference, with 22% correction in the HR group and 60% in APS group (P < 0.001). Conclusion. Our study finds axial rotation correction using APSs and a direct vertebral body derotation technique was significantly greater than that obtained with the HR construct.

The use of a transition rod may prevent proximal junctional kyphosis in the thoracic spine after scoliosis surgery: a finite element analysis.

Study Design. Finite element analysis. Objective. Via finite element analysis: (1) to demonstrate the abnormal forces present at the top of a scoliosis construct, (2) to demonstrate the importance of an intact interspinous and supraspinous ligament (ISL/SSL) complex, and (3) to evaluate a transition rod (a rod that has a short taper to a smaller diameter at one end) as an implant solution to diminish these pathomechanics, regardless of the integrity of the ISL/SSL complex. Summary of Background Data. The pathophysiology of increased nucleus pressure and increased angular displacement may contribute to proximal junctional kyphosis. Furthermore, high implant stress can be demonstrated at the upper end of the construct, possibly leading to the risk of implant failure. Methods. A finite element model was constructed to simulate a thoracic spinal fusion. The model was altered to remove the ISL/SSL complex at the level above the construct. Then, the model was altered again by extending the construct one level superior with a transition rod. The angular displacement, the maximum pressure in the nucleus, and stress within the implant were extracted from computational results under 2 conditions: load control and displacement control. The testing was performed with both titanium and stainless steel implants. Results. Pressure in the nucleus and angular displacement are all increased when the ISL/SSL complex is removed immediately above the instrumented levels, whereas the screw pullout force and maximum stress within the screw are decreased. The nucleus pressure increases by more than 50%. The angular displacement increases by 19% to 26%. This absence of the ISL/SSL complex simulates the clinical scenario that occurs when these structures are iatrogenically detached. Abnormal mechanics can be restored to normal level by extending the construct rostral one level with a transition rod. Furthermore, the elevated nucleus pressure and angular displacement noted even when the ISL/SSL complex is intact can be avoided with the use of a transition rod. Under the same bending moment (3 Nm), the nucleus pressure at the level immediately cephalad is up to 23% lower than the pressure in a standard construct. The angular displacement is 18% to 19% less than the standard construct. The maximum implant stress is also decreased by as much as 60%. Conclusion. Finite element modeling suggests that the pathomechanics at the proximal end of a scoliosis construct may be diminished by preserving the ISL/SSL complex and possibly completely eliminated with the use of rods with a diameter transition at the most proximal level.

More experienced surgeons less likely to fuse: a focus group review of 315 hypothetical EOS cases.

Introduction: Previous work has identified significant variability in decision making and multiple areas of clinical equipoise in the treatment of early-onset scoliosis (EOS). In an attempt to better understand possible determinants of this variability, we examined the relationship between socioclinical attributes of 11 participating surgeons and decision making regarding the treatment of EOS. Methods: Eleven experienced EOS surgeons were surveyed. The first part of the survey consisted of questions regarding surgeon and practice demographics. Next, surgeons were queried regarding their preferred management of 315 hypothetical EOS cases. Cases varied considerably in etiology [idiopathic, and low-tone and high-tone neuromuscular (HTNM)], age, and curve severity and progression. Treatment options were analyzed both individually and grouped as conservative (observation, bracing, or casting) versus surgical (spine-based or rib-based distraction, growth guidance, growth modulation, or definitive fusion). An “outlier” variable was created to determine the extent of a surgeon’s deviation from the group in management decisions. A univariate and multivariate regression analysis to identify statistical associations between physician characteristics and their management decisions in the presented hypothetical cases was performed. Results: The cohort’s mean years in practice was 20.7±7.36 years. Fifty-six percent of the cohort held Chest Wall and Spine Deformity Study Group (CWSDSG) membership and 56% were members of the Growing Spine Study Group. Multivariate regression demonstrated more years of practice predicted a lower preference for fusion (P<0.05). This effect was greater among HTNM cases (P<0.05). Overall, there was equal interest among groups regarding the choice between rib-based and spine-based distraction methods; however, for the subset of patients with HTNM scoliosis, membership in the CWSDSG (P<0.05) and the percentage of practice spent treating spinal deformity (P<0.05) predicted more rib-based distraction use. Conclusions: EOS surgeons with more experience were less likely to opt for definitive fusion. Use of rib-based distraction methods was common across surgeons in both study groups and within various cohorts of patients. Level of Evidence: Level V (survey of experts).

Chronic spinal cord injury in the pediatric population: does magnetic resonance imaging correlate with the International Standards for Neurological Classification of Spinal Cord Injury examination?

Study Design. Prognostic, retrospective case series. Objective. This study is part of a larger investigation to develop and validate a standardized and reliable method to evaluate and classify the neurologic consequence of spinal cord injury (SCI) in children. Such an instrument may also find use in the evaluation of patients with concomitant brain injury and/or cognitive impairment. We examined the relationship between the International Standards for Neurologic Classification of Spinal Cord Injury (ISCSCI) examination and magnetic resonance imaging (MRI) findings in a pediatric SCI population. Summary of Background Data. Recently, the reliability of the ISCSCI in young children with SCI who are unable to cognitively engage in the examination has been called into question. This has important implications as appropriate classification of these patients is necessary for prognostication, follow-up care, and appropriate placement into clinical trials. Methods. Our longitudinal pediatric SCI database was reviewed for children with chronic SCI (>6 months), ISCSCI examinations performed by experienced testers, and adequate MRIs of the spine. ISCSCI results were correlated with MRI findings. Twenty-six subjects were identified. Results. Overall, good to excellent relationships between ISCSCI neurologic level (NL) and MRI level of injury were found [Kendall &tgr; correlation coefficient 0.90 (P < 0.001)]. The ISCSCI NL was on an average, two-thirds of a vertebral level cephalad to the center of the lesion on MRI. One child with MRI evidence of cord disruption tested incomplete at ISCSCI examination. Conclusion. The ISCSCI examination was found to have good to excellent relationships with MRI level in children with chronic SCI. Our results suggest MRI may be a useful adjunct for the determination of NL in children unable to participate with the examination. Our results also suggest caution in using the ISCSCI for the determination of completeness in young children. Further research into new methods (e.g., diffusion tensor imaging) to determine completeness of injury is warranted.

Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis—The Pelvis and Other Considerations

STUDY DESIGN Prospective multicenter database study. OBJECTIVES To assess the incidence of proximal junctional kyphosis (PJK) in operative adolescent idiopathic scoliosis (AIS) using contemporary surgical techniques and to identify risk factors for PJK. The incidence of PJK has been reported as high as 46% in AIS. Factors associated with PJK have been incompletely explored. METHODS Prospectively enrolled 851 AIS patients (2000-2011, 78.5% female, average 14.4 years) were evaluated 2 years postoperatively. Radiographic and sagittal spinopelvic parameters and rod contour angle (RCA), a new measure that reflects the proximal contouring of the rod, were independently evaluated for association with PJK based on Lenke type. Multivariate logistic regression with backward elimination was performed to identify risk factors for PJK. RESULTS Overall PJK incidence was 7.05% and varies based on Lenke type (Lenke 1, 6.35%; Lenke 2 and 4, 4.39%; Lenke 3 and 6, 11.64%; and Lenke 5, 8.49%; p =.06). Among patients with Lenke 1 curves, risk factors for PJK were loss of kyphosis after surgery, and stopping caudal to the upper end vertebra (UEV). The risk of developing PJK increases by 7.1% with each lost degree of kyphosis compared with preoperation that occurs after the instrumentation is placed. For Lenke 2 and 4 curves, loss of kyphosis and more lordotic (negative) RCA were risk factors for PJK. For Lenke 3 and 6 curves, larger preoperative T5-T12 kyphosis was the only significant risk factor for PJK. Upper instrumented vertebra (UIV) at or cephalad to the UEV was associated with increased risk of PJK in Lenke 5 curves, which was contrary to the finding for Lenke 1 curves. No significant correlation was found between sagittal pelvic parameters and developing PJK. CONCLUSION The incidence of PJK in patients after surgery for AIS is 7.05% and varies based on Lenke type. Loss of kyphosis, larger preoperative kyphosis, UIV caudal to the proximal UEV (Lenke 1), UIV at or cephalad to the UEV (Lenke 5), and decreased RCA were the major risk factors for PJK in AIS. LEVEL OF EVIDENCE Level II.STUDY DESIGN Prospective multicenter database study. OBJECTIVES To assess the incidence of proximal junctional kyphosis (PJK) in operative adolescent idiopathic scoliosis (AIS) using contemporary surgical techniques and to identify risk factors for PJK. SUMMARY OF BACKGROUND DATA The incidence of PJK has been reported as high as 46% in AIS. Factors associated with PJK have been incompletely explored. METHODS Prospectively enrolled 851 AIS patients (2000-2011, 78.5% female, average 14.4 years) were evaluated 2 years postoperatively. Radiographic and sagittal spinopelvic parameters and rod contour angle (RCA), a new measure that reflects the proximal contouring of the rod, were independently evaluated for association with PJK based on Lenke type. Multivariate logistic regression with backward elimination was performed to identify risk factors for PJK. RESULTS Overall PJK incidence was 7.05% and varies based on Lenke type (Lenke 1, 6.35%; Lenke 2 and 4, 4.39%; Lenke 3 and 6, 11.64%; and Lenke 5, 8.49%; p = .06). Among patients with Lenke 1 curves, risk factors for PJK were loss of kyphosis after surgery, and stopping caudal to the upper end vertebra (UEV). The risk of developing PJK increases by 7.1% with each lost degree of kyphosis compared with preoperation that occurs after the instrumentation is placed. For Lenke 2 and 4 curves, loss of kyphosis and more lordotic (negative) RCA were risk factors for PJK. For Lenke 3 and 6 curves, larger preoperative T5-T12 kyphosis was the only significant risk factor for PJK. Upper instrumented vertebra (UIV) at or cephalad to the UEV was associated with increased risk of PJK in Lenke 5 curves, which was contrary to the finding for Lenke 1 curves. No significant correlation was found between sagittal pelvic parameters and developing PJK. CONCLUSION The incidence of PJK in patients after surgery for AIS is 7.05% and varies based on Lenke type. Loss of kyphosis, larger preoperative kyphosis, UIV caudal to the proximal UEV (Lenke 1), UIV at or cephalad to the UEV (Lenke 5), and decreased RCA were the major risk factors for PJK in AIS. LEVEL OF EVIDENCE Level II.

Outcomes of Spinal Fusion for Cervical Kyphosis in Children with Neurofibromatosis

BACKGROUND Cervical kyphosis may occur with neurofibromatosis type I (NF1) and is often associated with vertebral dysplasia. Outcomes of cervical spinal fusion in patients with NF1 are not well described because of the rarity of the condition. We aimed to (1) characterize the clinical presentation of cervical kyphosis and (2) report the outcomes of posterior and anteroposterior cervical fusion for the condition in these children. METHODS The medical records and imaging studies of 22 children with NF1 who had undergone spinal fusion for cervical kyphosis (mean, 67°) at a mean age of 11 years and who had been followed for a minimum of 2 years were reviewed. RESULTS Thirteen children presented with neck pain; 10, with head tilt; 9, with a previous cervical laminectomy or fusion; and 5, with a neurologic deficit. Two patients had spontaneous dislocation of the mid-cervical spine without a neurologic deficit. Eleven had scoliosis, with the major curve measuring a mean of 61°. Nine patients underwent posterior and 13 underwent anteroposterior surgery. Twenty-one received spinal instrumentation, and 1 was not treated with instrumentation. Preoperative halo traction was used for 9 patients, and it reduced the mean preoperative kyphosis by 34% (p = 0.0059). At the time of final follow-up, all spinal fusion sites had healed and the cervical kyphosis averaged 21° (mean correction, 69%; p < 0.001). The cervical kyphosis correction was significantly better after the anteroposterior procedures (83%) than after the posterior-only procedures (58%) (p = 0.031). Vertebral dysplasia and erosion continued in all 17 patients who had presented with dysplasia preoperatively. Thirteen patients had complications, including 5 new neurologic deficits and 8 cases of junctional kyphosis. Nine patients required revision surgery. Junctional kyphosis was more common in children in whom ≤5 levels had been fused (p = 0.054). CONCLUSIONS Anteroposterior surgery provided better correction of cervical kyphosis than posterior spinal fusion in children with NF1. Erosion of vertebral bodies continued during the postoperative follow-up period in all patients who had presented with dysplastic changes preoperatively. The cervical spine should be screened in all children with NF1. Fusion should include at least 6 levels to prevent junctional kyphosis. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Although Inconvenient, Baclofen Pumps Do Not Complicate Scoliosis Surgery in Patients with Cerebral Palsy

Study Design. Retrospective review of prospectively collected data. Objective. To compare patients with operative cerebral palsy with and without an intrathecal baclofen pump (ITB) to determine whether an ITB increases the complexity of scoliosis surgery and/or increases the risk of wound complications. Summary of Background Data. Options for baclofen pump placement include before, during, or after scoliosis surgery. There is some concern that prior placement of an ITB and catheter can further complicate cerebral palsy scoliosis surgery and increase the risk for wound complications. Methods. Prospectively collected cases from a multicenter cerebral palsy scoliosis database were reviewed for patients who underwent posterior spinal instrumentation and fusion for a major coronal deformity. These patients were then divided on the basis of whether they had ITB at the time of initial scoliosis surgery. The 2 groups were compared to determine differences in demographics, operative parameters, radiographical outcomes, and rates of wound complications. Results. Of 187 patients identified, 32 had an ITB previously placed (ITB group) and 155 did not (non-ITB group). Both groups were similar in regard to age, sex, Gross Motor Function Classification Scale score, and preoperative Cobb magnitude. When comparing operative parameters, there were no differences in the total operating room time (ITB = 375 ± 127 min, non-ITB = 423 ± 178 min; P = 0.149) or total estimated blood loss (ITB = 2323 ± 1489 mL, non-ITB = 2081 ± 1572 mL; P = 0.424). Postoperatively, the 2 groups had similar correction rates (71% vs. 67%, P = 0.303). As for perioperative wound complications, there were no differences in rates (P = 0.546) between the ITB (16%) and non-ITB group (15%). Conclusion. Although it may be inconvenient for the surgeon, ITBs do not increase the complexity of surgery or the risk for wound complications. When counseling patients and their caregivers on the timing of pump placement, it does not seem to compromise the care of the patient if the baclofen pump is placed first. Further study is needed to evaluate the safety of pump placement during or after scoliosis surgery. Level of Evidence: 4

Cervical pseudomeningocele due to occult hydrocephalus.

Study Design. Case report with a brief review of the literature. Objective. To describe a rare clinical presentation of post-traumatic hydrocephalus (PTH) in a child who sustained a complete cervical spinal cord injury (SCI). Summary of Background Data. The incidence of PTH can be as high as 30% in cases of pediatric SCI and traumatic brain injury. Presentation may include gait disturbance, altered mental status, or incontinence. To our knowledge, this is the first documentation of PTH presenting as a postsurgical pseudomeningocele. Methods. An 8-year-old girl involved in a motor vehicle accident sustained a C2–C3 fracture dislocation resulting in a complete SCI. She was initially treated with C2–C3 sublaminar wiring and halo placement. At postoperative week 6, the patient underwent drainage of a posterior cervical pseudomeningocele and repair of a small dural leak at C2–C3. She subsequently exhibited signs of altered mental status, and computed tomography scan revealed a significant hydrocephalus. Results. Emergent ventriculostomy was performed, and was converted to a ventriculo-peritoneal shunt 2 days later. The patients neurologic status markedly improved, and she continues to do well at 2 months after surgery. Conclusion. PTH presenting as a pseudomeningocele is extremely rare. In a patient with polytrauma and concomitant traumatic brain injury, the spine surgeon should consider hydrocephalus as a potential cause for a postsurgical pseudomeningocele, even several months after initial injury.