Factor analysis of the SRS-22 outcome assessment instrument in patients with adult spinal deformity.

PURPOSE: Designed for patients with adolescent idiopathic scoliosis, the SRS-22 is now widely used as an outcome instrument in patients with adult spinal deformity (ASD). No studies have confirmed the four-factor structure (pain, function, self-image, mental health) of the SRS-22 in ASD and under different contexts. Factorial invariance of an instrument over time and in different languages is essential to allow for precise interpretations of treatment success and comparisons across studies. This study sought to evaluate the invariance of the SRS-22 structure across different languages and sub-groups of ASD patients. METHODS: Confirmatory factor analysis was performed on the 20 non-management items of the SRS-22 with data from 245 American English-, 428 Spanish-, 229 Turkish-, 95 French-, and 195 German-speaking patients. Item loading invariance was compared across languages, age groups, etiologies, treatment groups, and assessment times. A separate sample of SRS-22 data from 772 American surgical patients with ASD was used for cross-validation. RESULTS: The factor structure fitted significantly better to the proposed four-factor solution than to a unifactorial solution. However, items 14 (personal relationships), 15 (financial difficulties), and 17 (days off work) consistently showed weak item loading within their factors across all language versions and in both baseline and follow-up datasets. A trimmed SRS (16 non-management items) that used the four least problematic items in each of the four domains yielded better-fitting models across all languages, but equivalence was still not reached. With this shorter version there was equivalence of item loading with respect to treatment (surgery vs conservative), time of assessment (baseline vs 12 months follow-up), and etiology (degenerative vs idiopathic), but not age (< vs ≥50 years). All findings were confirmed in the cross-validation sample. CONCLUSION: We recommend removal of the worst-fitting items from each of the four domains of the SRS-instrument (items 3, 14, 15, 17), together with adaptation and standardization of other items across language versions, to provide an improved version of the instrument with just 16 non-management items.

Triggered electromyographic threshold for accuracy of thoracic pedicle screw placement in a porcine model.

STUDY DESIGN: A porcine model of thoracic pedicle screw insertion was used to determine the effect of screw position on triggered electromyographic response. OBJECTIVE: To develop a model of intraoperative detection of misplaced thoracic pedicle screws. SUMMARY OF BACKGROUND DATA: Triggered electromyographic stimulation has been a valuable aid in determining appropriate placement of lumbar pedicle screws. The use of pedicle screws is increasing in the thoracic spine. Misplaced thoracic pedicle screws may have significant implications if the spinal cord is injured. This study was an attempt to determine whether the established lumbar model can be used for thoracic pedicle screws. METHODS: Five 120- to 150-lb domestic pigs had 85 pedicle screws placed bilaterally in the thoracic spine at each level from T6 to T15. Screws were inserted entirely in the pedicle (Group A). After removal of the medial pedicle wall, the screws were reinserted in the pedicle with no neural contact (Group B). The screws were then placed with purposeful contact with the neural elements (Group C). The screws were stimulated, eliciting an electromyographic response in the intercostal muscles for each instrumented level. The type of response noted was classified as either primary (response from appropriate nerve root), secondary (response at different root) or no response (response at different root, no response at appropriate root). RESULTS: Two hundred fifty responses were recorded. A primary response was noted in 72% of recordings. There was a relatively consistent decrease in the triggered electromyographic response from Group A (mean 4.15 +/- 1.80 mA) to Group C (mean 3.02 +/- 2.53 mA) screws (P = 0.0003). There was little difference in the response obtained from Group A to Group B (mean 4.37 +/- 2.48 mA) screws (P > 0.05). When a primary response was recorded, the mean threshold electromyographic response recorded was significantly lower than recordings with secondary and no response recordings (P < 0.05). CONCLUSION: Even though there was a consistent decrease between the A and C screws that was more definitively separated when a primary response was elicited, it was not possible to determine a cutoff trigger electromyographic level that would consistently differentiate intraosseous from epidural pedicle screw placement. Furthermore, this method could not differentiate screws clearly in the pedicle from screws with medial pedicle wall breakthrough. A more direct method of spinal cord monitoring must be established to provide the surgeon with early warning of the potential of neural injury in the placement of thoracic pedicle screws.

Prospective radiographic and clinical outcomes and complications of single solid rod instrumented anterior spinal fusion in adolescent idiopathic scoliosis.

STUDY DESIGN: Prospective clinical cases series. OBJECTIVES: To prospectively evaluate outcomes and critically review radiographic results and complications associated with single solid rod anterior spinal fusions in adolescent idiopathic scoliosis with 2-year minimum follow-up (range, 2-6 years). METHODS: Ninety consecutive patients at a single institution with thoracic (n = 43) or thoracolumbar/lumbar (n = 47) adolescent idiopathic scoliosis were treated by one of two surgeons with a similar anterior surgical technique using rib autograft, intradiscal structural (Harms) cages placed below T12, and anterior single solid rod convex compressive instrumentation. The patients were evaluated prospectively with the Scoliosis Research Society outcome instrument and upright radiographs before surgery and minimum 2-year follow-up. RESULTS (RADIOGRAPHIC): The average coronal correction of thoracic curves was from 55 degrees to 29 degrees (47%). The average correction of thoracolumbar/lumbar curves was from 50 degrees to 15 degrees (70%). In the sagittal plane, kyphosis was improved in thoracic fusions from 23 degrees to 30 degrees (T5-T12) and lordosis maintained in thoracolumbar/lumbar fusions at -58 degrees (T12-sacrum). Five patients (5.5%) developed a pseudarthrosis, four with implant failure. Three of five required a posterior fusion for a reoperation rate of 3.3%. The fourth and fifth patients were asymptomatic and appeared fused at the 2-year follow-up, with minimal loss of correction. Common risk factors for pseudarthrosis were smoking (4 of 5), weight >70 kg (4 of 5), and for thoracic pseudarthrosis, hyperkyphosis >40 degrees T5-T12 (2 of 3). RESULTS (CLINICAL OUTCOME): Scoliosis Research Society domain average scores were improved for function, pain, and self-image (P < 0.01). With the Scoliosis Research Society satisfaction domain, 88% responded that they were satisfied with their results and 89% would undergo the same treatment again. Four of five patients with pseudarthrosis did not have statistically significant lower final Scoliosis Research Society scores than those with solid fusions (93 vs. 97, P = 0.18). CONCLUSION: Anterior instrumented fusions for adolescent idiopathic scoliosis using a single solid rod had good radiographic and clinical outcomes. Consideration should be given to alternate techniques in larger adolescents (>70 kg) with thoracic hyperkyphosis (>40 degrees ), and smoking should be avoided. Poor radiographic outcomes did not correlate with final Scoliosis Research Society scores.

Spontaneous proximal thoracic curve correction after isolated fusion of the main thoracic curve in adolescent idiopathic scoliosis.

STUDY DESIGN: Retrospective clinical, radiographic, and patient outcome review of surgically treated adolescent idiopathic scoliosis. OBJECTIVES: To evaluate the spontaneous correction of the noninstrumented proximal thoracic (PT) curve after isolated correction of the main thoracic (MT) curve by either an anterior (ASF) or posterior (PSF) instrumentation and fusion. SUMMARY OF BACKGROUND DATA: There are no studies comparing the structural PT curve response after anterior versus posterior instrumented fusion of the MT curve in adolescent idiopathic scoliosis. METHODS: Eighty-five patients (single surgeon) with adolescent idiopathic scoliosis underwent operative instrumentation and fusion of their MT curve. All patients had a PT curve > or =20 degrees (average 29 degrees, range 20-49 degrees; average residual side-bending 18 degrees, range 3-42 degrees ) and were evaluated for preoperative PT curve flexibility and postoperative curve correction after PSF with the PT curve not instrumented (n = 44) and ASF with the PT curve not instrumented (n = 41). Minimum follow-up was 2 years (average, 3.6 years). Preoperative, 1 week postoperative, and latest follow-up (minimum 2-year) full-length radiographs were evaluated for the PT, MT, and thoracolumbar-lumbar coronal, side-bending, and sagittal Cobb measurements, as well as T1 tilt, clavicle angle, radiographic shoulder height, and the PT, MT, and thoracolumbar-lumbar apical vertical translation. A patient outcome questionnaire was also completed to correlate patient satisfaction with respect to their shoulder balance and overall appearance. RESULTS: The two groups were found to be statistically equivalent (P = 0.66) in terms of preoperative PT curve, MT curve, and MT side-bending curves, with the PT side benders slightly more flexible for the ASF (43%) versus the PSF group (31%) (P = 0.02). RADIOGRAPHIC: The spontaneous improvement in the PT curve was significant (P < 0.0001) in both groups. Additionally, this correction was maintained over time. However, the spontaneous PT curve correction was significantly greater after an ASF versus PSF correction of the MT curve on both the immediate postoperative (P =0.017) and minimum 2-year (P = 0.0024) evaluations, whereas the MT curve correction was the same in both groups (P = 0.45). There was no difference in the postoperative sagittal change in the PT curve (P = 0.12) between the two groups, and there was no difference in radiographic shoulder height (P = 0.5883). PATIENT OUTCOME: Both groups reported improvement in shoulder balance and clinical appearance, but there was no statistical difference between the two groups (P = 0.24). Additionally, no patients reported deterioration in either parameter. CONCLUSIONS: Spontaneous proximal thoracic curve correction consistently occurs after instrumented correction of the main thoracic curve. Furthermore, this spontaneous correction is as good as or slightly better after an ASF versus PSF of the MT curve. The preoperative side bender radiographs (PT curve flexibility) positively correlate with the postoperative spontaneous PT curve correction.

Minimum 2-year analysis of sacropelvic fixation and L5-S1 fusion using S1 and iliac screws.

STUDY DESIGN: An analysis of lumbosacral fusions for high-grade spondylolisthesis fusions with reduction and long fusions to the sacrum in ambulatory adults. OBJECTIVE: To assess the clinical and radiographic results of lumbosacral fusions using bilateral S1 and iliac screws. SUMMARY OF BACKGROUND DATA: S1 screws often fail with lumbosacral fusions, whereas L5-S1 pseudarthrosis is common in patients with deformity. MATERIALS AND METHODS: A total of 81 patients (38 revision, 43 primary) with minimum 2-year follow-up (average, 4.2 years; range, 2.0-7.1 years) underwent L5-S1 fusion using S1 and iliac screws (158 screws). Forty-nine of 81 constructs (61%) included an anterior load-sharing/fixation device. Group 1 included isthmic spondylolisthesis (n = 42), whereas Group 2 included long fusions (> or =3 levels) to the sacrum (n = 39). In Group 2, 15 patients (Group 2A) were fused from L1, L2, or L3 to the sacrum (3-5 levels, average 3.3 levels) and 24 patients (Group 2B) were fused from the thoracic spine to the sacrum (6-17 levels, average 11.5 levels). Twelve patients had pseudarthrosis at L5-S1. A patient questionnaire was completed. RESULTS: A total of 36 of the 38 revision patients had previous iliac crest harvesting, yet iliac screws were placed in 34 of 36 patients. Overall, 78 of 80 patients had iliac crest harvesting (one not attempted). None had loss of screw fixation or iliac crest fracture after harvesting. Four of the 81 patients (4.9%) had pseudarthrosis at L5-S1 after reconstruction. This included solid fusion in 10 of 12 patients presenting with L5-S1 pseudarthrosis. Fourteen percent of patients experienced some discomfort over the iliac screws; however, only one patient required screw removal. CONCLUSIONS: Bilateral iliac screws coupled with bilateral S1 screws provide excellent distal fixation for lumbosacral fusions with a high fusion rate (95.1%) in high-grade spondylolisthesis and long fusions to the sacrum. Previous iliac crest harvesting does not prevent ipsilateral screw placement (34 of 36 patients) or additional iliac harvesting (78 of 80 patients).

String test measurement to assess the effect of spinal deformity correction on spinal canal length.

STUDY DESIGN: Long cassette coronal and lateral radiographs before and after surgical correction were analyzed and string test measurements made by three observers in 55 surgical cases (13 surgical types). OBJECTIVES: The purpose of the study was to assess the effect of various corrective maneuvers for spinal deformity on the spinal canal length. SUMMARY OF BACKGROUND DATA: When perioperative neurologic deficit occurs, the surgeon removes implants because they are displaced into the spinal canal or the canal has been lengthened. It is important to know the effect certain constructs have on canal length because the ability of the spinal cord to adapt to canal lengthening is variable. METHODS: On the coronal radiographs the concave, convex, midvertebral, and adjusted midvertebral line, and on the sagittal radiographs, the anterior and posterior vertebral body lines were measured. The adjusted coronal line was the assumed path of the spinal cord starting at the midportion of the vertebral body at the top and the bottom of the deformity and then in between, hugging the pedicles as closely as possible while staying inside the pedicles. Adjustments for magnification were made. RESULTS: Anterior compression instrumentation without cages (n = 5) consistently shortened the spinal canal (mean delta -6.67 +/- 2.30 mm, P = 0.003), whereas instrumentation with cages (n = 13) lengthened the canal (mean delta 10.54 +/- 7.58 mm, P = 0.0003). Thoracic curves treated by posterior corrective forces (n = 14) demonstrated lengthening of the canal (mean delta 10.14 +/- 5.23 mm, P = 0.0001), large (n = 5) curves (81-140 degrees, mean delta 13.47 +/- 7.05 mm), and medium (n = 7) curves (50-80 degrees, mean delta 8.43 +/- 3.24 mm). CONCLUSIONS: Many deformity correction maneuvers, although they do not directly include application of posterior or anterior distraction forces, do indirectly lengthen the spinal canal.

Preoperative gait comparisons between adults undergoing long spinal deformity fusion surgery (thoracic to L4, L5, or sacrum) and controls.

STUDY DESIGN: This investigation compared the gait of revision and primary spinal deformity patients about to undergo surgical reconstruction with that of a group of able-bodied controls. OBJECTIVES: The hypothesis of the study was that both patient groups would have significantly compromised gait, spine motion, and gait endurance compared with the able-bodied group. SUMMARY OF BACKGROUND DATA: There is a population of adults with degenerative changes superimposed on idiopathic scoliosis who present for reconstructive spinal surgery (primary patients). There is another group of adults who have already had spinal deformity surgery and present for revision surgery (revision patients). METHODS: Twenty-seven women were recruited (8 primary, 13 revision, 6 able-bodied controls). A typical gait analysis was performed. Walking endurance was estimated from a submaximal graded treadmill exercise test. Three motion variables describing the orientation of the shoulders with respect to the pelvis in the three principal planes of the body were determined. Also, gait speed, stride length, cadence, and step width were calculated. The variable for the endurance test was the length of time walked on the treadmill. RESULTS: Results for the revision group indicated a slower walking speed, greater sagittal plane trunk flexion, reduced range of motion in the coronal and transverse planes, and poorer endurance relative to age-matched controls. The primary group demonstrated a slower walking speed relative to age-matched controls. The revision group had poorer endurance scores relative to the primary group. CONCLUSION: This investigation is an objective report describing the compromised gait and walking endurance of adult patients with spinal deformity before spinal fusion surgery. Results supported subjective observations regarding the preoperative gait of these patients and presented results difficult to observe in a clinical setting. The techniques appear useful in providing objective information regarding the gait abilities of these patients.

Adolescent idiopathic scoliosis: a new classification to determine extent of spinal arthrodesis.

BACKGROUND: The lack of a reliable, universally acceptable system for classification of adolescent idiopathic scoliosis has made comparisons between various types of operative treatment an impossible task. Furthermore, long-term outcomes cannot be determined because of the great variations in the description of study groups. METHODS: We developed a new classification system with three components: curve type (1 through 6), a lumbar spine modifier (A, B, or C), and a sagittal thoracic modifier (-, N, or +). The six curve types have specific characteristics, on coronal and sagittal radiographs, that differentiate structural and nonstructural curves in the proximal thoracic, main thoracic, and thoracolumbar/lumbar regions. The lumbar spine modifier is based on the relationship of the center sacral vertical line to the apex of the lumbar curve, and the sagittal thoracic modifier is based on the sagittal curve measurement from the fifth to the twelfth thoracic level. A minus sign represents a curve of less than +10 degrees, N represents a curve of 10 degrees to 40 degrees, and a plus sign represents a curve of more than +40 degrees. Five surgeons, members of the Scoliosis Research Society who had developed the new system and who had previously tested the reliability of the King classification on radiographs of twenty-seven patients, measured the same radiographs (standing coronal and lateral as well as supine side-bending views) to test the reliability of the new classification. A randomly chosen independent group of seven surgeons, also members of the Scoliosis Research Society, tested the reliability and validity of the classification as well. RESULTS: The interobserver and intraobserver kappa values for the curve type were, respectively, 0.92 and 0.83 for the five developers of the system and 0.740 and 0.893 for the independent group of seven scoliosis surgeons. In the independent group, the mean interobserver and intraobserver kappa values were 0.800 and 0.840 for the lumbar modifier and 0.938 and 0.970 for the sagittal thoracic modifier. These kappa values were all in the good-to-excellent range (>0.75), except for the interobserver reliability of the independent group for the curve type (kappa = 0.74), which fell just below this level. CONCLUSIONS: This new two-dimensional classification of adolescent idiopathic scoliosis, as tested by two groups of surgeons, was shown to be much more reliable than the King system. Additional studies are necessary to determine the versatility, reliability, and accuracy of the classification for defining the vertebrae to be included in an arthrodesis.

Prospective dynamic functional evaluation of gait and spinal balance following spinal fusion in adolescent idiopathic scoliosis.

STUDY DESIGN: Prospective evaluation of gait and spinal-pelvic balance parameters in patients with adolescent idiopathic scoliosis undergoing a spinal fusion. OBJECTIVE: To evaluate changes in gait and three-dimensional alignment and balance of the spine relative to the pelvis as a consequence of spinal fusion. SUMMARY OF BACKGROUND DATA: Preoperative and postoperative spinal radiographs have been the major forms of outcome analysis of adolescent idiopathic scoliosis fusions. The use of optoelectronic analysis for posture and gait has gained acceptance recently. However, there is a paucity of data quantifying, comparing, and correlating structural and functional changes in patients undergoing scoliosis fusion surgery including upright posture and gait. METHODS: Thirty patients with adolescent idiopathic scoliosis undergoing an instrumented spinal fusion were prospectively evaluated. Coronal and sagittal vertical alignment was evaluated on radiographs (CVA-R, SVA-R), during upright posture (CVA-P and SVA-P), and during gait (CVA-G, SVA-G). Transverse plane alignment was evaluated by the acromion-pelvis angle during gait. RESULTS: Gait speed was significantly decreased (P < 0.05) between preoperative (129 +/- 16 cm/sec) and 2-year postoperative (119 +/- 16 cm/sec) testing sessions. Decreasing gait speed was the result of significantly reduced cadence and decreased stride length. There were no significant differences for lower extremity kinematics over the entire gait cycle. Spinal-pelvic balance parameters showed significant improvement in mean CVA-R, CVA-G (P < 0.05), then unchanged CVA-P at 2 years postoperation. CVA-P was relatively unchanged while the mean CVA-G also showed significant improvement from preoperation (2.2 +/- 2.4 cm) to 2 years postoperation (1.3 +/- 1.3 cm)(P < 0.05). The mean SVA-R, SVA-P, and SVA-G were unchanged at 2 years postoperation (P > 0.05). The acromion-pelvis angle during gait at maximum shoulder rotation was statistically improved at 1 year (P = 0.002) and 2 years (P = 0.001) after surgery. Importantly, CVA-P correlated with CVA-G, and SVA-P correlated with SVA-G to the P < 0.05 level. CONCLUSIONS: Patients with adolescent idiopathic scoliosis undergoing spinal fusion show slightly decreased gait speed at 2 years postoperation without any change in lower extremity kinematics. Spinal-pelvic balance parameters are improved in the coronal plane and unchanged in the sagittal plane radiographically and during standing posture and gait. Transverse plane parameters also are improved at maximum shoulder rotation during gait.

Complications and results of long adult deformity fusions down to l4, l5, and the sacrum.

STUDY DESIGN: This is a consecutive study of patients having undergone surgical treatment of adult lumbar scoliosis. Follow-up ranged from 2 to 13 years (average 5 years). OBJECTIVES: To assess the complications and outcomes of patients with long fusions to L4 (n=23), L5 (n=21), or the sacrum (n=15) and determine if a "deeply seated" L5 segment is protective. SUMMARY OF BACKGROUND DATA: Few studies assess outcomes and complications in adults fused from the thoracic spine to L4, L5, or the sacrum with minimum 2-year follow-up. METHODS: Fifty-eight patients (59 cases; average age 43 years; range 21 to 60) with minimum 2-year follow-up were analyzed for subsequent spinal degeneration and complications. Outcomes were assessed from questionnaires administered at latest follow-up. RESULTS: Sixteen percent of cases (7 of 44) fused short of the sacrum displayed subsequent postoperative distal spinal degeneration, although only three patients were symptomatic. Compared with the group with no subsequent degeneration, this group had a lower improvement in function and pain relief. Other complications for patients fused short of the sacrum included two cases with crosslink breakage, one with neurologic deficit, three with pseudarthroses, one with hook pullout, and one with L5 screw pullout. For cases fused to the sacrum, two cases with deep wound infections and one with loose iliac screw requiring removal were observed. Because two of four cases fused to L5 with subsequent degeneration at L5-S1 were observed to have "deeply seated" L5 segments and two of the four did not, the authors could conclude only that "deep seating" of L5 is not absolute protection. CONCLUSIONS: Fusions short of the sacrum did not have predictable long-term results. Those fused short of the sacrum who developed distal spinal degeneration had worse outcomes. Patients fused to the sacrum did not have a higher complication rate. A "deeply seated" L5 segment does not necessarily protect the L5-S1 disc.

Long-term complications in adult spinal deformity patients having combined surgery a comparison of primary to revision patients.

STUDY DESIGN: This is a comparison of primary (N = 18) to revision (N = 26) combined (anterior and posterior surgery) adult spinal deformity patients with regard to late (>6 months) complications and radiographic/functional outcomes at a minimum 2-year follow-up. OBJECTIVES: To determine whether revision status increases the risk of late complications or offers a poor prognosis for functional outcome in adult deformity patients. SUMMARY OF BACKGROUND DATA: It is known that patients who have combined surgery for adult deformity have a high incidence of perioperative complications. Long-term complications and the effect of revision status have not been clarified in the literature. The functional outcomes for these patients are unclear as to whether or not there is a difference between primary and revision patients. Outside the arena of adult spinal deformity the functional outcomes for revision cases have been disappointing. METHODS: A consecutive series of 44 patients who underwent combined procedures for adult spinal deformity were followed for a minimum of 2 years (average follow-up 42 months). Clinical data were obtained by chart and radiographic review. Major complications were considered to be deep wound infection, pseudarthrosis, transition syndrome, neurologic deficit, and death. Minor complications considered were asymptomatic instrumentation failure (without loss of correction), instrumentation prominence requiring removal, and proximal or distal junctional segmental kyphosis (5-10 degrees ) or subsequent disc space narrowing of 2-5 mm without clinical symptoms. The patients also completed the AAOS Lumbar/Scoliosis MODEMS questionnaires aimed at assessing pain, function, and satisfaction. RESULTS: Minor complications were comparable in both groups: 4 of 18 (22%) in the primary group and 6 of 26 (23%) in the revision group. Major complications were slightly more frequent in the primary group with five complications in 4 patients (4 of 18 patients) (22%) compared with 3 of 26 patients (12%) in the revision group. The incidence of pseudarthrosis was 22% (4 of 18) for the primary group and 4% (1 of 26) for the revision group (P< 0.14). Forty of 44 patients completed the questionnaires. The primary patients functioned at a slightly higher level after surgery than the revision group. The level of pain was also slightly lower at final follow-up in the primary group. Despite these differences, the revision group had a higher level of patient satisfaction. CONCLUSION: At a minimum 2-year follow-up the late complications were not higher in the revision patients than in the primary group. The rate of major long-term complications, specifically pseudarthroses, was higher in the primary group. Patient satisfaction was higher in the revision patients, probably because they were experiencing a greater level of perceived pain and dysfunction at the time of their reconstruction.

Prospective randomization of parenteral hyperalimentation for long fusions with spinal deformity: its effect on complications and recovery from postoperative malnutrition.

STUDY DESIGN: A prospective randomized study of total parenteral nutrition for long spinal deformity fusions as well as its effect on complications and recovery from postoperative malnutrition was performed. OBJECTIVES: To determine whether the administration of total parenteral nutrition to patients undergoing same-day or staged long spinal fusions has an effect on postoperative nutritional parameter depletion, time for return to preoperative nutritional baseline, and complication rate. SUMMARY OF BACKGROUND DATA: Several studies have suggested, but only one has demonstrated, that perioperative administration of total parenteral nutrition to patients undergoing spinal reconstructive surgery may reduce postoperative nutritional depletion, thereby decreasing postoperative complications. METHODS: In this study, 46 patients undergoing same-day or staged spinal reconstruction surgery (> or = 10 levels) were randomized to receive or not receive total parenteral nutrition after surgery. The nutritional parameters of albumin, prealbumin, transferrin, total protein, and absolute lymphocyte count were obtained before surgery and at regular intervals after surgery until at least four out of five parameters were within 10% of their preoperative baseline value. Perioperative data and complications were tallied. RESULTS: There were no complications related to total parenteral nutrition administration. There was no statistical difference in total complications between those who did and those who did not receive total parenteral nutrition. However, there was a trend (P < 0.073) for the total parenteral nutrition group to return to nutritional baseline quicker. A significant increase in transferrin (P < 0.0082) and prealbumin (P < 0.015) depletion occurred in the patients who did not receive total parenteral nutrition. The anterior/posterior-same-day patients receiving total parenteral nutrition had more major complications (P < 0.033) and significantly more total protein depletion (P < 0.018) than the anterior/posterior-staged patients receiving total parenteral nutrition, possibly because the anterior/posterior-staged group received significantly more days(P < 0.0155) of total parenteral nutrition than the anterior/posterior-same-day group. In controlling for the number of days of total parenteral nutrition, no significant difference between type of surgery and complications was found. CONCLUSIONS: The administration of postoperative total parenteral nutrition to patients with spinal deformity is safe. No statistical reduction in complications occurred in the total parenteral nutrition group despite a trend toward more rapid normalization of nutritional parameters and a decrease in postoperative nutritional depletion. The anterior/posterior-staged group with the administration of total parenteral nutrition had a lower overall complication rate and a decreased incidence of postoperative nutritional depletion than the one-stage reconstruction group. The difference in the complication rates between the two groups may relate as much to the staging as to the administration of total parenteral nutrition per se. For certain cases it may be more advisable to stage patients and deliver total parenteral nutrition than to manage the cases in a continuous (i.e., same-day) fashion.

Prospective comparison of flexibility radiographs in adolescent idiopathic scoliosis.

STUDY DESIGN: A prospective evaluation of radiographs in patients undergoing anterior spinal fusion or posterior spinal fusion for adolescent idiopathic scoliosis. OBJECTIVE: To determine the most effective preoperative radiographic method for evaluating coronal plane flexibility by comparing preoperative and postoperative correction. SUMMARY OF BACKGROUND DATA: Curve flexibility is traditionally evaluated with side-bending radiographs. Recently, the fulcrum-bending radiograph was shown to provide better correction of thoracic curves undergoing posterior spinal fusion but was not evaluated in thoracolumbar/lumbar curves or in patients undergoing anterior spinal fusion. METHODS: Preoperative coronal radiographs of 46 consecutive patients undergoing spinal fusion for adolescent idiopathic scoliosis obtained while standing, lying supine, side-bending (maximally bending while supine), push-prone (padded bolsters applied to chest wall while prone), and fulcrum-bending (curve apex suspended over a radiolucent fulcrum while lateral) were compared with standing postoperative radiographs. Cobb angles were determined and evaluated for statistical significance. RESULTS: The fulcrum-bending radiograph demonstrated statistically better correction than other preoperative methods for main thoracic curves (P < 0.01) but fell short of demonstrating the correction obtained surgically. There was no statistical difference between side-bending, fulcrum-bending, or postoperative correction for thoracolumbar/lumbar curves (all P values > 0.07). The left side-bending was the most effective method for reducing upper thoracic curves (P < 0.001). There was no difference in the results obtained for curves corrected by anterior spinal fusion or anterior spinal fusion. CONCLUSION: To achieve maximal preoperative correction, thoracic fulcrum-bending radiographs should be obtained for evaluating main thoracic curves, whereas side-bending radiographs should continue to be used for evaluating both upper thoracic and thoracolumbar/lumbar curves.

Treatment of spinal stenosis and fixed sagittal imbalance.

Most commonly, sagittal imbalance associated with stenosis is seen with a hypolordotic fusion mass, junctional kyphosis, and junctional stenosis. If the deformity is flexible, it can be treated with anterior and posterior fusion with anterior structural grafting. If it is fixed, which it usually is, then a pedicle subtraction procedure with decompression and extension of the fusion usually is the most suitable operative approach.

The effect of nerve-root injections on the need for operative treatment of lumbar radicular pain. A prospective, randomized, controlled, double-blind study.

BACKGROUND: The purpose of the present study was to determine the effectiveness of selective nerve-root injections in obviating the need for an operation in patients with lumbar radicular pain who were otherwise considered to be operative candidates. Although selective nerve-root injections are used widely, we are not aware of any prospective, randomized, controlled, double-blind studies demonstrating their efficacy. METHODS: Fifty-five patients who were referred to four spine surgeons because of lumbar radicular pain and who had radiographic confirmation of nerve-root compression were prospectively randomized into the study. All of the patients had to have requested operative intervention and had to be considered operative candidates by the treating surgeon. They then were randomized and referred to a radiologist who performed a selective nerve-root injection with either bupivacaine alone or bupivacaine with betamethasone. The treating physicians and the patients were blinded to the medication. The patients were allowed to choose to receive as many as four injections. The treatment was considered to have failed if the patient proceeded to have the operation, which he or she could opt to do at any point in the study. RESULTS: Twenty-nine of the fifty-five patients, all of whom had initially requested operative treatment, decided not to have the operation during the follow-up period (range, thirteen to twenty-eight months) after the nerve-root injections. Of the twenty-seven patients who had received bupivacaine alone, nine elected not to have the operation. Of the twenty-eight patients who had received bupivacaine and betamethasone, twenty decided not to have the operation. The difference in the operative rates between the two groups was highly significant (p < 0.004). CONCLUSIONS: Our data demonstrate that selective nerve-root injections of corticosteroids are significantly more effective than those of bupivacaine alone in obviating the need for a decompression for up to thirteen to twenty-eight months following the injections in operative candidates. This finding suggests that patients who have lumbar radicular pain at one or two levels should be considered for treatment with selective nerve-root injections of corticosteroids prior to being considered for operative intervention.

Deep wound infections after neuromuscular scoliosis surgery: a multicenter study of risk factors and treatment outcomes.

STUDY DESIGN: A retrospective case-control study evaluating risk factors for infection, causative organisms, and results of treatment in patients with cerebral palsy or myelomeningocele who underwent fusion for scoliosis was performed. OBJECTIVES: To identify risk factors for infection, and to characterize the infections in terms of infecting organisms and response to treatment. SUMMARY OF BACKGROUND DATA: No previous studies have analyzed risk factors or causative organisms, nor have they indicated results of treatment for infections in this group of patients. METHODS: After a 10-year retrospective review of 210 surgically treated patients, deep wound infections developed in 16 patients with myelomeningocele and 9 patients with cerebral palsy. These patients were studied extensively for possible risk factors, along with 50 uninfected patients matched for age, diagnosis, and year of surgery. Statistical testing was performed to identify risk factors. The courses of the infections were characterized in terms of organisms isolated and response to treatment. Treatment was performed in a stepwise fashion and classified in terms of the most successful step: debridement and closure, granulation over rods, or instrumentation removal. RESULTS: Of the 10 risk factors tested, 2 were found to be significant: degree of cognitive impairment and use of allograft. Findings showed that 52% of the infections were polymicrobial. Gram-negative organisms were isolated as commonly as gram-positive organisms. The most common organisms were coagulase-negative Staphylococcus, Enterobacter, Enterococcus, and Escherichia coli.- Debridement and closure were successful in 11 of 25 patients with deep wound infection. Of the 14 patients with infection not resolved by serial debridements and closure, 2 were managed successfully by allowing the wound to granulate over rods, and 7 required rod removal for persistent wound drainage. There were three symptomatic pseudarthroses. Infections resulting from gram-positive organisms were most often managed successfully with debridement and closure (P = 0.012). CONCLUSIONS: Patients with cerebral palsy or myelomeningocele who have severe cognitive impairment, and those who received allograft may be at increased risk for infection. Infections are more often polymicrobial and caused by gram-negative organisms than is typical for elective orthopedic procedures. This suggests an enteric source. Treatment with debridement and closure was not always successful. Patients in whom infection develops are then at increased risk for pseudarthrosis.

The effect of variation in arm position on sagittal spinal alignment.

STUDY DESIGN: A prospective radiographic analysis of sagittal alignment in patients with and without previous spinal fusion. OBJECTIVES: To evaluate the effect of variation of arm position on the segmental, regional, and global sagittal radiographic spinal alignment. In addition, to determine whether spinal fusion has any influence on the effect of variation in arm position on the sagittal spinal alignment. SUMMARY OF BACKGROUND DATA: Importance of segmental, regional, and global sagittal alignment has been widely promoted. However, no mention has been made of arm positioning during a lateral spinal radiograph and the resultant effects it may have on sagittal alignment and balance. METHODS: Prospective evaluation of 40 consecutive patients with and 40 consecutive patients without a previous spinal fusion was performed. The patients had lateral long cassette radiographs performed in a standardized fashion with the first radiograph obtained with the patient's arms raised horizontally forward at 90 degrees of flexion at the shoulder, and the second radiograph obtained with arms raised horizontally forward at 30 degrees of flexion at the shoulder. Standard segmental, regional, and global sagittal alignments were measured and statistically compared. RESULTS: In comparing group 1 (patients with spinal fusion) to group 2 (patients without spinal fusion), there was no statistically significant difference in segmental and regional sagittal alignments. However, positioning the arms at 90 degrees versus 30 degrees resulted in a negative shift of the sagittal vertical axis (SVA) in patients that was statistically significant (P = 0.038) for those with (-6 mm at 90 degrees vs +4 mm at 30 degrees ), but not (P = 0.119) for those patients without (-8 mm at 90 degrees vs -4mm at 30 degrees ) a previous spinal fusion. CONCLUSIONS: Based on the findings in this study, the authors recommend positioning the arms at 30 degrees of forward flexion from the vertical when obtaining a long cassette lateral radiograph of the entire spine.

Prospective pulmonary function evaluation following open thoracotomy for anterior spinal fusion in adolescent idiopathic scoliosis.

STUDY DESIGN: Prospective study. OBJECTIVES: To prospectively evaluate sequential pulmonary function tests (PFTs) at a minimum 2-year follow-up after an open anterior spinal fusion (ASF) with instrumentation for thoracic AIS. SUMMARY OF BACKGROUND DATA: Anterior spinal fusion with instrumentation is currently undergoing evaluation as an alternative to posterior spinal fusion (PSF) for thoracic adolescent idiopathic scoliosis (AIS). However, the effect of an open thoracotomy on pulmonary function in these patients is unknown. METHODS: Fifty-one patients with thoracic AIS with an average age of 15+0 (range 11+2 to 20+5) had PFTs consisting of volume (FVC), flow (FEV-1), and total lung capacity (TLC). Parameters were obtained preoperatively, and at 3 months, 1 year, and a minimum 2-year follow-up. All patients had a single or double open thoracotomy with the diaphragm kept intact. Fusion levels ranged from T4 (most proximal) to L1 (most distal). The average preoperative thoracic coronal Cobb measurement was 53 degrees (range 38 degrees to 80 degrees ), and the average postoperative coronal measurement was 24 degrees (range 7 degrees to 49 degrees ). The average preoperative thoracic sagittal kyphosis (T5-T12) averaged 22 degrees (range 10 degrees to 58 degrees ), and the average postoperative sagittal kyphosis measured 29 degrees (range 7 degrees to 67 degrees ). RESULTS: There was a significant decline (P< or =0.05) in PFT absolute values (L) of 19%-FVC, 15%-FEV-1, and 11%-TLC at 3 months postoperatively with subsequent improvement and no statistical difference between preoperative and 2-year postoperative values. When evaluating percent predicted values, there was a statistical decline (P< or =0.05) at 3 months postoperatively averaging 19% FVC, 14% FEV-1, and 12% TLC. These values returned to within 94% to 96% of baseline by the 2-year follow-up visit, but were still statistically less than the preoperative values (P

A prospective comparison of neurogenic mixed evoked potential stimulation methods: utility of epidural elicitation during posterior spinal surgery.

STUDY DESIGN: A prospective study of 50 patients who underwent posterior thoracic or thoracolumbar instrumented spinal surgery from June 1998 through June 1999. OBJECTIVES: To highlight the advantages and disadvantages of neurogenic mixed evoked potential (NMEP) data obtained with three methods of stimulation: epidural, spinous process, and percutaneous. SUMMARY OF BACKGROUND DATA: Reports in the literature have established the efficacy of epidural, spinous process, and percutaneous stimulation of the NMEP response. The three methods have not been compared for reliability, sensitivity, and specificity. METHODS: The study group consisted of 50 patients who underwent posterior thoracic or thoracolumbar instrumented spinal surgery from June 1998 through June 1999. Somatosensory-evoked potentials were used to monitor upper and lower extremities. An attempt to obtain NMEPs was made in all patients by using percutaneous (PERC-NMEP), spinous process (SP-NMEP), and epidural (EPI-NMEP) stimulation. These data were evaluated for reliability, sensitivity, and specificity. The number of minutes monitored in the postcorrection period were calculated for each method, and stimulus intensities were noted. RESULTS: In the current study, PERC-NMEPs were obtained in 88% of the patients and were maintained in 91% of those cases, SP-NMEPs were obtained in 96% and maintained in 77%, and EPI-NMEPs were obtained in 100% and maintained in 88%. Data collection continued in the postcorrection period for 46 minutes for PERC-NMEPs, 19 minutes for SP-NMEPs, and 23 minutes for EPI-NMEPs. The study group had no true-positive or false-negative findings. CONCLUSIONS: Results showed that EPI-NMEPs provide reliable data in a greater number of patients than either SP-NMEPs or PERC-NMEPs. However, PERC-NMEP data are readily maintained during and after the critical time window after corrective spinal maneuvers. The NMEPs elicited with both percutaneous and epidural stimulation have a useful role in an intraoperative spinal cord-monitoring protocol.

Parents' and patients' preferences and concerns in idiopathic adolescent scoliosis: a cross-sectional preoperative analysis.

STUDY DESIGN: A multicenter cross-sectional study of parents' and patient's concerns and preferences regarding surgery for idiopathic scoliosis. OBJECTIVES: The purpose of this study was to analyze independently both the parents' and patients' assessments of upcoming surgery for idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: No group has recently reported querying patients and their parents regarding expectations, preferences, reasons, and concerns about and for surgical treatment of adolescent idiopathic scoliosis. METHODS: Ninety-one sets of parents and patients were separately asked to complete questionnaires regarding the patients' upcoming idiopathic scoliosis surgery. Patients' ages ranged from 9 to 18 years, and data were collected from four centers and seven surgeons (all active members of the Scoliosis Research Society) from April through December 1998. Thirty-nine questions covered concerns (n = 6), reasons for surgery (n = 14), expectations (n = 9), assessment of life as is (n = 5), and scar preference (n = 5). RESULTS: The greatest concern about the surgery expressed by both parents and patients was neurologic deficit. The least concern for both was location and appearance of the scar. The highest expectation and main reason for having the surgery was to reduce future pain and disability as an adult. Families would be either somewhat or very dissatisfied to spend the rest of life "as is." CONCLUSION: Although parents and patients had similar ratings and concerns, the parents' concerns were higher, and expectations were greater than the patients'.