STUDY DESIGN.Retrospective review of a prospectively collected multicenter database.
OBJECTIVE.To assess how “overcorrection” of the main thoracic curve without control of the proximal curve ...increases the risk for shoulder imbalance in Lenke type 1 Adolescent Idiopathic Scoliosis (AIS).
SUMMARY OF BACKGROUND DATA.Postop shoulder imbalance is a common complication following AIS surgery. It is thought that a more cephalad upper-instrumented vertebra (UIV) decreases the risk of shoulder imbalance in Lenke type 1 and 2 curves; however, this has not been proven.
METHODS.Thirteen surgeons reviewed preop and 5-year postop clinical photos and PA radiographs of patients from a large multicenter database with Lenke type 1 and 2 AIS curves who were corrected with pedicle screw/rod constructs. Predictors of postop shoulder imbalance were identified by univariate analysis; multivariate analysis was done using the classification and regression tree method to identify independent drivers of shoulder imbalance.
RESULTS.One hundred forty-five patients were reviewed. The UIV was T3-T5 in 87% of patients, with 8.9% instrumented up to T1 or T2. Fifty-two (36%) had shoulder imbalance at 5 years. On classification and regression tree analysis when the proximal thoracic (PT) Cobb angle was corrected more than 52%, 80% of the patients had balanced shoulders. Similarly, when the PT curve was corrected less than 52% and the main thoracic (MT) curve was corrected less than 54%, 87% were balanced. However, when the PT curve was corrected less than 52%, and the MT curve was corrected more than 54%, only 41% of patients had balanced shoulders (P = 0.05). This relationship was maintained regardless of the UIV level.
CONCLUSION.In Lenke type 1 and 2 AIS curves, significant correction of the main thoracic curve (>54%) with simultaneous “under-correction” (<52%) of the upper thoracic curve resulted in shoulder height imbalance in 59% of patients, regardless of the UIV. This suggests the PT curve must be carefully scrutinized in order to optimize shoulder balance, especially when larger correction of the MT curve is performed.Level of Evidence2
STUDY DESIGN.Retrospective cohort.
OBJECTIVE.This radiographic analysis using a full-body x-ray evaluated the ways in which the sagittal profiles of the unfused spinal segments, pelvic, and lower ...extremities spontaneously change after adolescent idiopathic scoliosis (AIS) surgery with segmental pedicle screw constructs.
SUMMARY OF BACKGROUND DATA.Reciprocal lordotic changes in unfused spinal segments after corrective surgery for AIS have been reported. However, a full-body analysis has not been studied.
METHODS.The sagittal profiles of 51 (age ≤18) patients with AIS undergoing corrective surgery with segmental pedicle screw constructs were investigated. Patients were divided into two groupsgroup T; selective thoracic fusion and group L; fusion to the low lumbar spine. They were further subcategorized according to preoperative thoracic kyphosis (TKT5–12)hypokyphotic (TK <20°) and normohyperkyphotic (TK >20°) groups. The postoperative change in the sagittal parameters and the correlation between the instrumented thoracic alignment change (ΔT2−12) and reciprocal changes of unfused segments were analyzed.
RESULTS.At baseline, the entire cohort had a relatively hypokyphotic thoracic spine (TK25.5° ± 13.7°), low T1 slope (13.6° ± 7.7°), and kyphotic cervical spine (C2–7 lordosis7.7° ± 13.1°). The lower extremities were in neutral alignment overall. Postoperatively, the cervical alignment changed significantly lordotic (average −13.4° increased lordosis) after the adequate preservation of TK (average 17.8° increased kyphosis) in the hypokyphotic group T. Linear correlations were observed between ΔT2–12 and spontaneous reciprocal changes in C2–7 lordosis, lumbar lordosis, and knee flexion angle in group T.
CONCLUSION.The sagittal profiles of patients with AIS can significantly change after adequate restoration of TK which averaged 17.8°, particularly in the cervical spine. Lordotic reciprocal change in the cervical spine as well as increase in lumbar lordosis can occur in a linear correlation after adequate restoration of TK. There were no significant changes that occurred in the pelvis or lower extremities after AIS corrective surgery.Level of Evidence4
Cervical spondylotic myelopathy (CSM) is one of the most common among causes of spinal cord dysfunction worldwide. In this article, we provide a broad narrative review of the options to treat CSM ...from an anterior approach to the cervical spine. Anterior procedures are effective and safe, especially for one or two level disease (although can be used up to 7-8 levels). This approach can be used in patients with lordotic, neutral, or kyphotic cervical spine alignment and provide excellent access for direct neural decompression. The most common adverse effects of anterior cervical operations are dysphagia and dysphonia, but fortunately, these are mild and transient in the majority of cases. Severe complications, such as vertebral arterial injury, spinal cord injury or airway compromise, are rare but must be taken into consideration, especially when additional risk factors are present (multilevel procedures, revision surgeries, older, and infirm patients). The primary anterior cervical procedures for treating CSM are anterior cervical discectomy and fusion (ACDF), anterior cervical corpectomy and fusion (ACCF), oblique cervical corpectomy, and cervical disc arthroplasty. A combination (hybrid) of ACDF and ACCF is also utilized as an option to allow for wide decompression, deformity correction, and provide more surface area of exposed, and bleeding cancellous bone. More recently, the senior author (KDR) has utilized a hemi-corpectomy and fusion hybrid technique which will be described in this text. Advantages and disadvantages of each of these options are discussed in detail, as well as the need for posterior instrumentation supplementation in selected patients; such as those with concomitant cervical deformity, poor bone quality, or those at risk for pseudarthrosis following multilevel arthrodeses. The management of patients with cervical spinal cord compression without myelopathy or with mild symptoms is also discussed.
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