Decision Making Algorithm for Adult Spinal Deformity Surgery.

Adult spinal deformity (ASD) is one of the most challenging spinal disorders associated with broad range of clinical and radiological presentation. Correct selection of fusion levels in surgical planning for the management of adult spinal deformity is a complex task. Several classification systems and algorithms exist to assist surgeons in determining the appropriate levels to be instrumented. In this study, we describe our new simple decision making algorithm and selection of fusion level for ASD surgery in terms of adult idiopathic idiopathic scoliosis vs. degenerative scoliosis.

Pedicle Screw Placement in the Thoracolumbar Spine Using a Novel, Simple, Safe, and Effective Guide-Pin : A Computerized Tomography Analysis.

OBJECTIVE: To improve pedicle screw placement accuracy with minimal radiation and low cost, we developed specially designed K-wire with a marker. To evaluate the accuracy of thoracolumbar pedicle screws placed using the novel guide-pin and portable X-rays. METHODS: Observational cohort study with computerized tomography (CT) analysis of in vivo and in vitro pedicle screw placement. Postoperative CT scans of 183 titanium pedicle screws (85 lumbar and 98 thoracic from T1 to L5) placed into 2 cadavers and 18 patients were assessed. A specially designed guide-pin with a marker was inserted into the pedicle to identify the correct starting point (2 mm lateral to the center of the pedicle) and aiming point (center of the pedicle isthmus) in posteroanterior and lateral X-rays. After radiographically confirming the exact starting and aiming points desired, a gearshift was inserted into the pedicle from the starting point into the vertebral body through the center of pedicle isthmus. RESULTS: Ninety-nine percent (181/183) of screws were contained within the pedicle (total 183 pedicle screws : 98 thoracic pedicle screws and 85 lumbar screws). Only two of 183 (1.0%) thoracic pedicle screws demonstrated breach (1 lateral in a patient and 1 medial in a cadaver specimen). None of the pedicle breaches were associated with neurologic or other clinical sequelae. CONCLUSION: A simple, specially designed guide-pin with portable X-rays can provide correct starting and aiming points and allows for accurate pedicle screw placement without preoperative CT scan and intraoperative fluoroscopic assistance.

Does correction of preoperative coronal imbalance make a difference in outcomes of adult patients with deformity?

STUDY DESIGN: Retrospective study with prospectively collected outcomes data. OBJECTIVE: Determine the significance of coronal balance on spinal deformity surgery outcomes. SUMMARY OF BACKGROUND DATA: Sagittal balance has been confirmed as an important radiographic parameter correlating with adult deformity treatment outcomes. The significance of coronal balance on functional outcomes is less clear. METHODS: Eighty-five patients with more than 4 cm of coronal imbalance who underwent reconstructive spinal surgery were evaluated to determine the significance of coronal balance on functional outcomes as measured with the Oswestry Disability Index (ODI) and Scoliosis Research Society outcomes questionnaires. Sixty-two patients had combined coronal (>4 cm) and sagittal imbalance (>5 cm), while 23 patients had coronal imbalance alone. RESULTS: Postoperatively, 85% of patients demonstrated improved coronal balance. The mean improvement in the coronal C7 plumb line was 26 mm for a mean correction of 42%. The mean preoperative sagittal C7 plumb line in patients with combined coronal and sagittal imbalance was 118 mm (range, 50-310 mm) and improved to a mean 49 mm. The mean preoperative and postoperative ODI scores were 42 (range, 0-90) and 27 (range, 0-78), for a mean improvement of 15 (36%) (P = 0.00001; 95% CI, 12-20). The mean Scoliosis Research Society scores improved by 17 points (29%) (P = 0.00). Younger age (P = 0.008) and improvement in sagittal balance (P = 0.014) were positive predictors for improved ODI scores. Improvement in sagittal balance (P = 0.010) was a positive predictor for improved Scoliosis Research Society scores. In patients with combined coronal and sagittal imbalance, improvement in sagittal balance was the most significant predictor for improved ODI scores (P = 0.009). In patients with preoperative coronal imbalance alone, improvement in coronal balance trended toward, but was not a significant predictor for improved ODI (P = 0.092). CONCLUSION: Sagittal balance improvement is the strongest predictor of improved outcomes in patients with combined coronal and sagittal imbalance. In patients with coronal imbalance alone, improvement in coronal balance was not a factor for predicting improved functional outcomes.

Free Hand Pedicle Screw Placement in the Thoracic Spine without Any Radiographic Guidance : Technical Note, a Cadaveric Study.

Thoracic pedicle screw fixation techniques are still controversial for thoracic deformities because of possible complications including neurologic deficit. Methods to aid the surgeon in appropriate screw placement have included the use of intraoperative fluoroscopy and/or radiography as well as image-guided techniques. We describe our technique for free hand pedicle screw placement in the thoracic spine without any radiographic guidance and present the results of pedicle screw placement analyzed by computed tomographic scan in two human cadavers. This free hand technique of thoracic pedicle screw placement performed in a step-wise, consistent, and compulsive manner is an accurate, reliable, and safe method of insertion to treat a variety of spinal disorders, including spinal deformity.

Decompression alone versus decompression with limited fusion for treatment of degenerative lumbar scoliosis in the elderly patient.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To analyze the surgical results of a group of patients older than 65 years treated for mild degenerative lumbar scoliosis (<30°) with stenosis, treated with decompression alone or decompression and limited fusion. METHODS: We evaluated 55 patients, all older than 65 years from our prospectively collected database with mild degenerative scoliosis (<30°) and stenosis who underwent surgery. Laminectomy alone was performed in 16 patients, and laminectomy and limited fusion in 39 patients. Mean follow-up was 4.6 years in the decompression group and 5.0 years in the fusion group. Clinical results were graded by patients' self-reported satisfaction and length of symptom-free period to recurrence. RESULTS: In the decompression alone group, 6 (37%) of 16 patients developed recurrent stenosis at the previously decompressed level and five developed recurrence within 6 months postoperatively versus the decompression and fusion group where 3 (8%) of 39 (P = .0476) developed symptomatic stenosis supra adjacent to the fusion. Of 16 patients in the decompression alone group, 12 (75%) had recurrence of symptoms by the 5-year follow-up period versus only 14 (36%) patients in the decompression and fusion group (P = .016). Adjacent segment degenerative changes were common in the fusion group, but only 7% developed symptomatic stenosis. CONCLUSIONS: Decompression with limited fusion prevents early return of stenotic symptoms compared with decompression alone in the setting of mild degenerative scoliosis (<30°) and symptomatic stenosis in patients 65 years and older. [Table: see text] The definiton of the different classes of evidence is available on page 67.

Cervical radiculopathy caused by vertebral artery loop formation : a case report and review of the literature.

Vertebral artery loop formation causing encroachment on cervical neural foramen and canal is a rare cause of cervical radiculopathy. We report a case of 61-year-old woman with vertebral artery loop formation who presented with right shoulder pain radiating to her arm for 2 years. Plain radiograph and computed tomography scan revealed widening of the right intervertebral foramen at the C5-6 level. Magnetic resonance imaging and angiogram confirmed the vertebral artery loop formation compressing the right C6 nerve root. We had considered microdecompressive surgery, but the patient's symptoms resolved after conservative management. Clinician should keep in mind that vertebral artery loop formation is one of important causes of cervical radiculopathy. Vertebral artery should be visualized using magnetic resonance angiography in suspected case.

Comparison study of the instrumented circumferential fusion with instrumented anterior lumbar interbody fusion as a surgical procedure for adult low-grade isthmic spondylolisthesis.

BACKGROUND: Instrumented circumferential fusion has been used as a primary and salvage procedure in lumbar spine fusion, especially for adult low-grade isthmic spondylolisthesis. Recently, instrumented anterior lumbar interbody fusion (ALIF) has been shown to provide good clinical and radiologic results that are comparable with those attained with traditional lumbar fusion. However, there have been no reports available that compare instrumented circumferential fusion with instrumented ALIF. METHODS: Between January 2003 and November 2004, a total of 43 consecutive patients underwent instrumented ALIF (group I) at one hospital of the authors. Between February 2003 and October 2006, a total of 32 consecutive patients underwent instrumented circumferential fusion (group II) at the other hospital of the authors. The authors retrospectively reviewed clinical and radiologic data from patients. The time spent on the operation, blood loss, blood transfusions, the length of hospital stay, complications, clinical results, and radiologic results, including disc height (DH), degree of listhesis, segmental lordosis (SL), and whole lumbar lordosis (WL), were analyzed and compared. Clinical outcomes were graded using visual analog scale (VAS) scores. Functional outcomes were measured using Oswestry Disability Index (ODI) scores and return-to-work status. RESULTS: The mean follow-up period was 41.1 and 32.9 months in group I and group II, respectively. Radiologic evidence of fusion was noted in 42 of 43 patients in group I and in 32 of 32 patients in group II. In both groups, all of the radiologic data, including the DH, degree of listhesis, SL, and WL significantly changed from the preoperative to postoperative period except for WL in group II. In both groups, VAS scores for back and leg pain and ODI scores significantly changed from the preoperative to postoperative period. There was no significant difference for VAS scores for back ODI scores in the two treatment groups after surgery. The mean time until return to work was 3.7 months in group I and 3.6 months in group II (p < .05). The mean hospital stay for group I (7.4 days) was shorter than that for group II (15.2 days) (p < .05). The mean operation time in group I (190 minutes) was shorter than that in group II (260.8 minutes) (p < .05). The mean blood loss in group I (300 mL) was less than that in group II (379 mL) (p < .05). CONCLUSIONS: According to the present clinical outcome, instrumented ALIF is at least as effective as instrumented circumferential fusion for the treatment of back pain in adult patients with low-grade isthmic spondylolisthesis. Moreover, in terms of operative data including the duration of operation and hospital stay, as well as blood loss, instrumented ALIF demonstrates better results.

Proximal junctional kyphosis in adult spinal deformity after segmental posterior spinal instrumentation and fusion: minimum five-year follow-up.

STUDY DESIGN: A retrospective study. OBJECTIVE: To analyze time-dependent change of, prevalence of, and risk factors for proximal junctional kyphosis (PJK) in adult spinal deformity after long (> or =5 vertebrae) segmental posterior spinal instrumented fusion with a minimum 5-year postoperative follow-up. SUMMARY OF BACKGROUND DATA: No study has focused on time-dependent long-term proximal junctional change in adult spinal deformity after segmental posterior spinal instrumented fusion with minimum 5-year follow-up. METHODS: Clinical and radiographic data of 161 (140 women/21 men) adult spinal deformity patients with minimum 5-year follow-up (average 7.8 years, range 5-19.8 years) treated with long posterior spinal instrumentation and fusion were analyzed. Radiographic measurements included sagittal Cobb angle at the proximal junction on preoperative, 8-weeks postoperation, 2-year postoperation, and ultimate follow-up (> or =5 years). Postoperative SRS outcome scores were also evaluated. RESULTS: The prevalence of PJK at 7.8 years postoperation was 39% (62/161 patients). The PJK group (n = 62) demonstrated a significant increase in proximal junctional angle at 8 weeks (59%), between 2 years postoperation and ultimate postoperation (35%), and in thoracic kyphosis (T5-T12) at ultimate follow-up (P = 0.001). However, the sagittal vertical axis change at ultimate follow-up did not correlate with PJK (P = 0.53). Older age at surgery >55 years (vs. < or =55 years) and combined anterior and posterior spinal fusion (vs. posterior only) demonstrated significantly higher PJK prevalence (P = 0.001, 0.041, respectively). The SRS outcome scores did not demonstrate significant differences with the exception of the self-image domain when PJK exceeded 20 degrees. CONCLUSION: The prevalence of PJK at 7.8 years postoperation was 39%. PJK progressed significantly within 8 weeks postoperation (59%) and between 2 years postoperation and ultimate follow-up (35%). Older age at surgery (>55 years) and combined anterior and posterior spinal fusion were identified as risk factors for developing PJK. The SRS outcome instrument was not adversely affected by PJK, except when PJK exceeded 20 degrees.

Prospective pulmonary function comparison of anterior spinal fusion in adolescent idiopathic scoliosis: thoracotomy versus thoracoabdominal approach.

STUDY DESIGN: Prospective clinical study of a retrospective database. OBJECTIVE: To compare the prospective pulmonary function changes following anterior spinal instrumentation and fusion through an open thoracotomy with the same procedure through a thoracoabdominal approach at 2 years follow-up. SUMMARY OF BACKGROUND DATA: Open anterior spinal instrumentation and fusion for adolescent idiopathic scoliosis (AIS) has been known to decrease pulmonary function after surgery. However, the differential effect of an open thoracotomy versus thoracoabdominal approach on pulmonary function in AIS is unknown. METHODS: Sixty-four AIS patients who underwent an anterior spinal instrumentation and fusion through an open thoracotomy (TC group) for a major main thoracic scoliosis were compared with 55 patients who underwent the same procedure through a thoracoabdominal approach (TA group) for a major thoracolumbar/lumbar (TL/L) scoliosis using pulmonary function tests assessing forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) before surgery and 2 years after surgery. The TC group was divided into 2 groups, TC group with thoracoplasty (1-5 ribs, n = 35) and TC group without thoracoplasty (n = 29). RESULTS: Preoperative and 2-year postoperative absolute FVC in the TC group averaged 3.05L and 2.74L, respectively (0.31L decrease, P < 0.0001) versus 3.27L and 3.21L, respectively (0.06L decrease, P = 0.15) in the TA group. The TC group demonstrated a significantly larger decrease in absolute FVC at 2 years postoperative (P < 0.0001). Preoperative and 2-year postoperative absolute FEV1 in the TC group averaged 2.56L and 2.35L, respectively (0.21L decrease, P < 0.0001) versus 2.82L and 2.81L, respectively (0.02L decrease, P = 0.67) in the TA group. The TC group demonstrated a significantly larger decrease in absolute FEV1 at 2 years postoperative (P = 0.001). TC patients with thoracoplasty (n = 35) demonstrated a similar average decrease (0.34L) of absolute FVC at 2 years postoperative compared with those without thoracoplasty (0.26L, P = 0.49) and a similar average decrease of absolute FEV1 at 2 years postoperative (0.23L vs. 0.19L without thoracoplasty, P = 0.76). CONCLUSION: An open thoracotomy approach for treating a main thoracic curve demonstrated a significant decrease in the absolute pulmonary function tests values at 2 years postoperative while the thoracoabdominal approach for treating a TL/L curve did not.

Operative treatment of adolescent idiopathic scoliosis with posterior pedicle screw-only constructs: minimum three-year follow-up of one hundred fourteen cases.

STUDY DESIGN: Preoperative review of a prospective study, single institution, consecutive series. OBJECTIVE.: To analyze the intermediate-term follow-up of consecutive adolescent idiopathic scoliosis (AIS) patients treated with pedicle screw constructs. SUMMARY OF BACKGROUND DATA: There have been no reports of the intermediate-term findings in North America following posterior spinal fusion with the use of pedicle screw-only constructs. METHODS: One hundred and fourteen consecutive patients having a minimum 3-year follow-up (mean 4.8 +/- 1.1; range, 3.0-7.3 years) with AIS were evaluated. The average age at surgery was 14.9 +/- 2.2 years. Radiographic measurements included preoperative (Preop), postoperative (PO), 2-year (2 years), and final follow-up (FFU). A chart review evaluated PFTs, Scoliosis Research Society scores, presence of thoracoplasty, Risser sign, Lenke classification, and complications. RESULTS: The most frequent curve pattern was Lenke type 1 (45.6%), followed by type 3 (21.9%). The average main thoracic curve measured 59.2 degrees +/- 12.2 SD Preop, and corrected to 16.8 degrees +/- 9.9 PO (P < 0.0001). Sagittal thoracic alignment (T5-T12) decreased from 25.8 degrees to 15.5 degrees at FFU (P = 0.05). Nash-Moe grading for apical vertebral rotation (AVR) in the proximal thoracic curve decreased from 2.0 Preop to 1.1 at FFU (P < 0.0001), and AVR in the thoracolumbar/lumbar spine decreased from 1.6 Preop to 1.1 at FFU (P < 0.0001). Importantly, the horizontalization of the subjacent disc measured -8.3 degrees Preop which decreased to -0.9 degrees PO (P < 0.001). PFT follow-up averaged 2.4 years with a 7.1% improvement in FVC (P = 0.004) and 8.8% in FEV1 (P < 0.0001). SRS scores averaged 83.0% at latest follow-up. Age, gender, Risser sign, or complications did not have a significant effect on outcomes. There were 2 cases of adding-on, 3 late onset infections, 1 with a single pseudarthrosis, but no neurologic complications. CONCLUSION: This is the largest (N = 114), consecutive series of North American patients with AIS treated with pedicle screws having a minimum of 3-year follow-up. The average curve correction was 68% for the main thoracic, 50% for the proximal thoracic, and 66% for the thoracolumbar/lumbar curve at final follow-up.

Loss of spinal cord monitoring signals in children during thoracic kyphosis correction with spinal osteotomy: why does it occur and what should you do?

STUDY DESIGN: A retrospective review of pediatric kyphosis patients undergoing a spinal cord-level osteotomy for correction. OBJECTIVE: To evaluate the prevalence, etiology, timing, and intervention related to loss of spinal cord monitoring data during surgical correction of pediatric kyphosis in the spinal cord region. SUMMARY OF BACKGROUND DATA: Although much has been written regarding the risks inherent to scoliosis surgery, there is less literature available regarding the neurologic outcomes of pediatric kyphosis surgery. As more surgeons contemplate posterior-only kyphosis correction with spinal cord-level osteotomies, the importance of maintaining spinal cord neurologic function is paramount. METHODS: Forty-two patients with pediatric kyphosis undergoing a posterior-only spinal reconstruction with a spinal cord level osteotomy or posterior-based vertebral column resection performed were reviewed. Patients were categorized by diagnosis, type and incidence of osteotomies, and loss of neurogenic mixed-evoked potential (NMEP) data. Interventions required to regain data and postoperative neurologic outcomes were also reviewed. RESULTS: Of the 42 patients, 9 (21.4%) demonstrated a complete loss of NMEP data sometime during surgery while concomitant somatosensory sensory-evoked potentials (SSEP) remained within acceptable limits of baseline values. All 9 patients had intraoperative intervention including: blood pressure elevation (n = 1), release of corrective forces (n = 2), blood pressure elevation and correction release (n = 3), malalignment/subluxation adjustment (n = 1), further bony decompression (n = 1), or restoration of anterior column height via a titanium cage along with further posterior decompression (n = 1). In all cases, SSEPs were unchanged and NMEPs returned varying from 8 to 20 minutes after loss, with all patients having a normal wake-up test intraoperatively and a normal neurologic examination after surgery. CONCLUSION: Intraoperative multimodality monitoring with some form of motor tract assessment is a fundamental component of kyphosis correction surgery in the spinal cord region in order to create a safer, optimal environment and to minimize neurologic deficit. The surgeon must be able to trust the information monitoring provides and act on it accordingly.

Results of lumbar pedicle subtraction osteotomies for fixed sagittal imbalance: a minimum 5-year follow-up study.

STUDY DESIGN: Retrospective study. OBJECTIVE: To report results at a minimum 5 years after pedicle subtraction osteotomy for fixed sagittal imbalance. SUMMARY OF BACKGROUND DATA: No one has reported results of pedicle subtraction osteotomies with a 5- to 8-year follow-up. METHOD: Thirty-five consecutive patients with sagittal imbalance (29 females/6 males, average age at surgery, 53.1 years) treated with lumbar pedicle subtraction osteotomies (1 at L1, 13 at L2, 20 at L3, and 1 at L4) at 1 institution were analyzed (average follow-up, 5.8 years; range, 5-7.6 years). Radiographic and clinical outcomes analysis was performed. RESULTS: There were no significant regional radiographic changes between 2 years postoperative and the ultimate follow-up (proximal junctional change, P = 0.30; thoracic kyphosis, P = 0.38; and lumbar lordosis, P = 0.84), although many patients did demonstrate an increasingly anterior C7 sagittal plumb with time. Ten pseudarthroses (29%) occurred in 8 patients and were revised between 2 and 5 years postoperative. There were no pseudarthroses at the osteotomy level (9 at the thoracolumbar junction, 1 at the LS junction), but at the levels added to the previous fusions. There was no degradation in Oswestry and Scoliosis Research Society (SRS) outcome scores between 2 years postoperative and ultimate follow-up (P = 0.23 and 0.90, respectively). Patients reported very good satisfaction (87%), good self-image (76%), good function (69%), and fair pain subscales (66%) at ultimate follow-up. Sagittal vertical axis <8 cm at ultimate follow-up was significant for better SRS outcomes scores (P = 0.038). Eight patients with revised pseudarthroses did not demonstrate poorer SRS outcomes scores (P = 0.52). Those 8 patients were queried after their pseudarthrosis revision surgery. CONCLUSION: Pedicle subtraction osteotomy can provide satisfactory clinical and radiographic outcomes for patients with a minimum 5-year follow-up despite needing pseudarthrosis revision and some component of increasingly positive sagittal vertical axis between 2 years and 5 to 8 years of follow-up. The level of patient satisfaction and self-image subscales were high after more than 5 years of follow-up. Restoration and maintenance of sagittal vertical axis <8 cm were important to the ultimate sagittal reconstruction.

Adult spinal deformity surgery: complications and outcomes in patients over age 60.

STUDY DESIGN: A retrospective analysis, including prospectively collected patient outcomes data. OBJECTIVE: To determine the rate of complications and outcomes in patients >or=60 years of age who underwent major spinal deformity surgery requiring a minimum 5-level arthrodesis procedure. SUMMARY OF BACKGROUND DATA: As the population ages, an increasing number of older patients are presenting with spinal deformity disorders that may require major reconstructive procedures. Previous studies have reported complication rates as high as 80% in this age group for 1- and 2-level fusion procedures. The prevalence of complications was found to increase with the greater number of levels fused. METHODS: Forty-six patients who were 60 years of age or older underwent a thoracic or lumbar arthrodesis procedure consisting of 5 levels or greater. Diagnosis, comorbidities, operative data, hospital data, major and minor complications, and deaths were recorded. Oswestry Disability Index (ODI) Scores were used to evaluate clinical outcomes. RESULTS: Thirty-eight females and 8 males with a mean age of 67 years (range, 60-85 years) and a mean follow-up of 4.2 years (range, 2-11 years) had complete records. Thirty-six (78%) patients had at least 1 comorbidity. Twenty-nine (63%) patients had at least 1 prior spinal surgery. A mean of 9 levels (range, 5-16 levels) were fused in each patient. The overall complication rate was 37%. The major complication rate was 20%. ODI improved from 49 to 25 for a mean improvement of 24 (49%) (P < 0.0001). CONCLUSION: The overall complication rate was 37% and the major complication rate was 20%. Increasing age was a significant factor (P < 0.05) in predicting the presence of a complication. Patients older than 69 years had more complications. The presence of a comorbidity had no association with complication rates and neither had an effect on final patient reported outcomes, which showed significant improvement (ODI preoperative, 49; postoperative, 25) (P < 0.0001).

The reliability of preoperative supine radiographs to predict the amount of curve flexibility in adolescent idiopathic scoliosis.

STUDY DESIGN: Retrospective review. OBJECTIVE: To determine the reliability of supine long-cassette radiographs as compared with side-bending films in predicting curve flexibility in operative cases of adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: The value of side-bending films is important in the classification of AIS, as well as predicting curve flexibility. METHODS: A total of 675 patients with a diagnosis of operative AIS were evaluated. All curves were classified by the Lenke classification. Coronal parameters included: proximal thoracic (PT), main thoracic (MT), and thoracolumbar/lumbar (TL/L) Cobb measurements; sagittal data including: T2-T5, T5-T12, and TL/L measurements. Curves were divided into Lenke Types 1 (N = 263), 2 (N = 118), 3 (N = 52), 4 (N = 31), 5 (N = 57), and 6 (N = 54). Lenke Types 1 to 4 (Group I-MT Major) were compared with Types 5 and 6 (Group II-TL/L Major). RESULTS: For Group I, MT supine films were highly predictive of MT side-bending while TL/L supine films were highly predictive of TL/L side-bending and standing films. An equation was derived to predict the value of the side-bending radiographs for each part of the curve. For Group II, MT supine films were highly predictive of MT side-bending and standing films. TL/L supine films were highly predictive of TL/L side-bending and standing films. Contingency table analysis for Group I resulted in the supine film providing a strong statistical ability to predict a nonstructural PT curve (sensitivity = 0.952, PPV = 0.864, NPV = 0.865) and also a nonstructural TL/L curve (sensitivity = 0.958, PPV = 0.916). Similarly, in Group II, we found a strong statistical ability to predict a nonstructural PT (sensitivity 1.00, PPV = 0.982, NPV = 1.00) and a nonstructural MT curve (sensitivity 0.789, specificity = 0.842, PPV = 0.833, NPV = 0.80). CONCLUSION: A single preoperative supine radiograph is highly predictive of side-bending radiographs and can be used as an adjunct to predicting curve type, flexibility, and structurality. Thus, this singular, reproducible, and non-effort-related radiograph can potentially replace the need for dual side-bending films.

Computed tomography evaluation of pedicle screws placed in the pediatric deformed spine over an 8-year period.

STUDY DESIGN: A retrospective review. OBJECTIVE: To evaluate the incremental accuracy of pedicle screws used in spinal deformity via a free-hand technique at a single institution over an 8-year period. SUMMARY OF BACKGROUND DATA: The in vivo accuracy of free-hand pedicle screws placed throughout the deformed spine as evaluated by computed tomography (CT) scanning is unknown over a long time period. METHODS: A total of 1023 pedicle screws inserted from T1 to L4 in 60 patients (928 screws in 54 scoliosis patients and 95 screws in 6 kyphosis patients) over an 8-year period were investigated via postoperative CT scans. Patients were divided into 3 groups (group I = 1998-1999, group II = 2001-2002, and group III = 2005). All pedicle screws were inserted via the free-hand technique using anatomic landmarks, specific entry sites, neurophysiologic, and radiographic confirmation. Pedicle screw position on CT scan was graded as acceptable versus violated, defined as the screw axis being outside the pedicle wall. RESULTS: One hundred seven of 1023 pedicle screws (10.5%) demonstrated significant mediolateral pedicle wall violations (19 medial vs. 88 lateral, P = 0.001). groups I and III had significantly higher lateral wall violations than group II (P < 0.05) as did the kyphotic spines (vs. scoliotic spine, P < 0.05). There were significantly more screws placed in the periapical region over time (P < 0.0001), with left-sided lateral violations (T5-T8) increasing from group II to group III, while the number of medial violations significantly decreased with time (P < 0.0001). Pedicle screws placed on the right side showed a significant decrease in accuracy from group II to group III (P = 0.03). The average transverse angle of the acceptable screws was 15.3 degrees which was significantly different from the medial (23.0 degrees , P < 0.001) and lateral (10.6 degrees , P < 0.001) violations between group I and group II. No screws demonstrated neurologic, vascular, or visceral complications. CONCLUSION: Overall accuracy of acceptable screws using the free-hand pedicle screw placement technique in the deformed spine was 89.5%, without any neurologic, vascular, or visceral complications over an 8-year period. The rate of medial violations decreased with time, as the number of screws placed in the periapical region increased.

Prospective pulmonary function comparison following posterior segmental spinal instrumentation and fusion of adolescent idiopathic scoliosis: is there a relationship between major thoracic curve correction and pulmonary function test improvement?

STUDY DESIGN: Prospective clinical study. OBJECTIVE: To investigate if a correlation exists between various parameters including major thoracic curve correction and postoperative pulmonary function test (PFT) improvement at 2 years postoperative following posterior segmental spinal fusion (PSSF) and instrumentation with iliac crest bone graft (ICBG). SUMMARY OF BACKGROUND DATA: There are no studies available on the correlation between major thoracic curve correction and postoperative PFT improvement following PSSF and instrumentation with ICBG with a homogenous diagnosis, similar operation method, and similar age population. METHODS: One hundred thirty-nine patients with adolescent idiopathic scoliosis (Lenke type 1-4), undergoing PSSF and instrumentation with ICBG at a single institution, were before surgery and 2 years after surgery prospectively evaluated in regard to PFTs, assessing forced vital capacity, and forced expiratory volume in 1 second. PFTs change at 2 years postoperative was compared by the various parameters including major thoracic Cobb curve correction and the types of instrumentation. We defined a significant clinical improvement as a 10% or more increase of percent predictive FEV1 value at 2 years postoperative. RESULTS: PSSF and instrumentation with ICBG demonstrated statistically significant improvement of absolute and percent-predicted PFTs at 2 years postoperative. There was a significant clinical improvement in 31 patients (22%) at 2 years postoperative. Significant clinical improvement was related to thoracic pedicle screw instrumentation (vs. thoracic hook instrumentation, P = 0.030). Absolute amount of major thoracic Cobb correction, magnitude of the residual curve, correction percentage of the major thoracic Cobb, the number of fused vertebrae, Risser sign, and age at surgery did not demonstrate any significant positive or negative correlation (-0.3

Comparison of thoracic pedicle screw to hook instrumentation for the treatment of adult spinal deformity.

STUDY DESIGN: Retrospective, case-control, matched cohort. OBJECTIVE: Compare the radiographic and clinical outcomes of adult spinal deformity patients treated with thoracic pedicle screw (TPS) or thoracic hook constructs. SUMMARY OF BACKGROUND DATA: The efficacy of TPS instrumentation for pediatric spinal deformity correction has been established. Little is known about TPS use in adult spinal deformity. METHODS: Fifty-six patients (average age, 49 years; average follow-up, 3.58 years) were treated with TPS or thoracic hook constructs for coronal (n = 20) or sagittal (n = 36) plane deformities. Patients were evaluated radiographically and with SRS scores. RESULTS: Coronal deformities treated with TPS demonstrated improved main thoracic curve correction compared with hook constructs at last follow-up (24.8 degrees vs. 13.8 degrees; P < 0.05), despite having larger (59.8 degrees vs. 44.9 degrees; P < 0.05) and more rigid preoperative curves (29.3% vs. 44.9% correction on side-bending radiographs; P < 0.001). Sagittal deformities treated with TPS constructs demonstrated greater thoracolumbar kyphosis correction than hook constructs at last follow-up (12.1 degrees vs. 2.5 degrees; P < 0.05). No TPS patient had a thoracic pseudarthrosis. Four hook patients (14%) had thoracic pseudarthroses. CONCLUSIONS: TPS instrumentation allows greater coronal and sagittal plane correction and may reduce the risk of thoracic pseudarthrosis compared with hook constructs when treating adult spinal deformities.

Adjacent segment disease followinglumbar/thoracolumbar fusion with pedicle screw instrumentation: a minimum 5-year follow-up.

STUDY DESIGN: Retrospective radiographic outcomes analysis. OBJECTIVE: We had 3 hypotheses: 1) a longer fusion; 2) a more proximal instrumented vertebra, and 3) circumferential fusion versus posterior-only fusion would increase the likelihood of adjacent segment disease (ASD). SUMMARY OF BACKGROUND DATA: The literature analyzing risk factors, prevalence, and presentation of patients with ASD is varied and without clear consensus. METHODS: A total of 188 patients with minimum 5-year follow-up who had lumbar/thoracolumbar fusion with pedicle screw instrumentation for degenerative disorders were included. Radiographic ASD was defined by: 1) development of spondylolisthesis >4 mm, 2) segmental kyphosis >10 degrees , 3) complete collapse of disc space, or 4) more than 2 grades worsening of Weiner classification. Clinical ASD was defined as 1) symptomatic spinal stenosis, 2) intractable back pain, or 3) subsequent sagittal or coronal imbalance. RESULTS: Radiographic ASD occurred in 42.6% (80 of 188) of patients. Patients with radiographic ASD had worse Oswestry scores (20.3 vs. 12.5; P = 0.001) at ultimate follow-up than those without ASD. Clinical ASD developed in 30.3% (57 of 188) of patients. Clinical ASD manifested as spinal stenosis (n = 47), instability-type back pain (n = 5), and sagittal or coronal imbalance (n = 5). Age at surgery over 50 years and length of fusion were significant risk factors for the development of ASD in the lumbar spine. Fusion to L1-L3 proximally increased the risk of ASD when compared with L4 and L5. Circumferential fusion versus posterior fusion was not a significant factor in the development of ASD. CONCLUSION: Patients over the age of 50 were at higher risk of developing clinical ASD than those 50 years old or younger. Length of fusion was a significant risk factor in the development of ASD in the lumbar spine. Fusion up to L1-L3 increased the risk of ASD when compared with L4 and L5. Circumferential fusion, as opposed to posterolateral fusion, was not a statistically significant risk factor for the development of ASD.

Proximal junctional kyphosis in adolescent idiopathic scoliosis after 3 different types of posterior segmental spinal instrumentation and fusions: incidence and risk factor analysis of 410 cases.

STUDY DESIGN: Retrospective study. OBJECTIVE: Determine proximal junctional kyphosis (PJK) prevalence and analyze risk factors associated with PJK in adolescent idiopathic scoliosis (AIS) patients following 3 different posterior segmental spinal instrumentation and fusion surgeries. SUMMARY OF BACKGROUND DATA: No comparison study exists on proximal junctional AIS changes following 3 different segmental posterior spinal instrumentation and fusion surgeries at 2 years postoperative. METHODS: A clinical/radiographic assessment was conducted in 410 consecutive AIS patients (average age = 14.7, range = 10.6-20) (men/women = 73/337) treated with instrumented segmental posterior spinal fusion with 2-year follow-up. Revision and anterior cases were not included. Standing long-cassette radiographic measurements were analyzed including various sagittal/coronal parameters for preoperative, early postoperative, and 2-year follow-up. Abnormal PJK was defined by proximal junction sagittal Cobb angles between the lower endplate of the uppermost instrumented vertebra and the upper endplate of 2 supradjacent vertebrae >or=+10 degrees and at least 10 degrees greater than the preoperative measurement at 2 years postoperative. RESULTS: PJK prevalence defined at 2 years postoperative was 27% (111 of 410 patients). Statistically significant factors: larger preoperative thoracic kyphosis angle (T5-T12 >40 degrees vs. T5-T12 10 degrees -40 degrees vs. T5-T12 <10 degrees ; P < 0.0001), greater immediate postoperative thoracic kyphosis angle decrease (decrease >5 degrees vs. 5 degrees decrease-5 degrees increase vs. increase >5 degrees ; P < 0.0001), thoracoplasty versus no thoracoplasty (P = 0.001), and men versus women (P = 0.007). Instrumentation types (hook-only vs. proximal hook, distal pedicle screw vs. pedicle screw P = 0.058), number of fused vertebrae >12 versus 12>or= (P = 0.12), the uppermost instrumented vertebra among T2, T3, T4, T5 (P = 0.75). There were no significant differences in Scoliosis Research Society Patient Questionnaire-24 outcome-scores (PJK total score = 97.0, self-image subscales = 21.3 vs. non-PJK group = 95.3, 21.0) (P = 0.34 total score, P = 0.54 self-image subscale). CONCLUSION: Two-year postoperative PJK prevalence in AIS following 3 different posterior segmental spinal instrumentation and fusion surgeries was 27%. A larger preoperative thoracic kyphosis angle, greater immediate postoperative thoracic kyphosis angle decrease, thoracoplasty, and male sex correlated significantly with PJK. There were no significant differences in Scoliosis Research Society Patient Questionnaire-24 outcome-scores between the PJK and non-PJK group.

Cross-cultural comparison of the Scoliosis Research Society Outcomes Instrument between American and Japanese idiopathic scoliosis patients: are there differences?

STUDY DESIGN: A comparative study. OBJECTIVE: To report a preliminary evaluation of the Scoliosis Research Society Outcomes Instrument (SRS-24) and determine whether differences in baseline scores exist between American and Japanese patients with idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Because the SRS outcomes instrument was primarily introduced for the American population, baseline scores in the Japanese population might differ from the American population. A comparative study using the SRS instrument between American and Japanese patients with idiopathic scoliosis has not been reported. METHODS: Two comparable groups of 100 idiopathic scoliosis patients before spinal fusion were separated into American (A) and Japanese (J). There were no statistically significant differences between the groups for gender (A: 9 men/91 women vs. J: 13 men/87 women), age (A: 15.0 +/- 2.4 vs. J: 14.9 +/- 3.8), main curve location (A: 77 thoracic/23 lumbar, J: 76 thoracic/24 lumbar), main curve Cobb angle (A: 50.5 +/- 5.2 vs. J: 51.1 +/- 8.7), and thoracic kyphosis (A: 20.9 +/- 14.3 vs. J: 19.9 +/- 12.1) (P > 0.05, for all comparisons). Patients were evaluated using the first section of the SRS-24 which was divided into 4 domains: total pain, general self-image, general function, and activity. SRS-24 scores were statistical compared in individual domains and questions using the Mann-Whitney U test. RESULTS: American patients had significantly lower scores in pain (P < 0.0001, A: 3.7 +/- 0.8 vs. J: 4.3 +/- 0.4), function (P < 0.01, A: 3.9 +/- 0.6 vs. J: 4.2 +/- 0.5), and activity (P < 0.0001, A: 4.5 +/- 0.8 vs. J: 4.9 +/- 0.3) domains compared with Japanese patients. Japanese patients had significantly lower scores in the self-image (P < 0.0001, A: 4.0 +/- 0.7 vs. J: 3.5 +/- 0.5) domain. With regard to individual questions, there were significant differences in the scores between the 2 groups for all questions except 5 and 13 (P < 0.05, for all comparisons). CONCLUSION: SRS-24 scores in the Japanese idiopathic scoliosis population differed from that of the American population. Japanese patients had less back pain, a negative self-image regarding back deformity, higher general physical function, and daily activity. It is highly probable that patient's perceptions differ due to cultural differences, which affect SRS-24 scores so a cross-cultural comparison of the SRS instrument content is necessary in the future.