Christopher L. Hamill

The impact of perioperative complications on clinical outcome in adult deformity surgery.

Study Design. Retrospective case-control series. Objective. The purpose of this study is to determine whether perioperative complications alter subsequent clinical outcome measures in adult spinal deformity surgery. Summary of Background Data. Increasingly, the benefit of surgical intervention is being evaluated based on patient reported outcomes and standardized health related quality of life (HRQOL) measures. As improvement or deterioration in HRQOL scores becomes a standard for clinical evaluation in adult spinal deformity, the correlation between HRQOL outcome scores and historic benchmarks, such as curve correction, sagittal balance, fusion healing, or the occurrence of a complication, must be clarified. Methods. This study analyzes a prospective multicenter data base for adult spinal deformity. Patients with major, minor, and no complications were matched using a logistic regression technique producing 46 patients in each group. Standardized outcome measures at baseline and at 1 year postop were compared. Results. Forty-seven major complications were reported in 46 patients. Sixty-two minor complications were noted in 46 patients. Comparison between the 3 complication groups revealed that 1-year postoperative outcome measures were not statistically different for the Scoliosis Research Society Outcomes Instrument, Medical Outcomes Short Form-36 (SF-12), Oswestry Disability Index, or Numerical Pain Scales. The only significant interaction was in the rate of change from preop to 1-year postop for the SF-12 general health subscale. For the group with major complications, SF-12 general health deteriorated by 2.1 points from preop to 1-year postop. During the same period, the group with minor complications experienced an improvement of 4.2 points and the group with no complications experienced an improvement of 1.5 points. Conclusion. This study suggests that risk for minor complications may be a less substantial obstacle than previously assumed for surgical treatment in adult spinal deformity. In contrast, major complications were reported in approximately 10% of cases and adversely affected outcome as evidenced by the deterioration in SF-12 general health scores at 1 year after surgery.

Risk-benefit assessment of surgery for adult scoliosis: an analysis based on patient age.

Study Design. Retrospective review of a prospective, multicenter database. Objective. The purpose of this study was to assess whether elderly patients undergoing scoliosis surgery had an incidence of complications and improvement in outcome measures comparable with younger patients. Summary of Background Data. Complications increase with age for adults undergoing scoliosis surgery, but whether this impacts the outcomes of older patients is largely unknown. Methods. This is a retrospective review of a prospective, multicenter spinal deformity database. Patients complete the Oswestry Disability Index (ODI), SF-12, Scoliosis Research Society-22 (SRS-22), and numerical rating scale (NRS; 0–10) for back and leg pain. Inclusion criteria included age 25 to 85 years, scoliosis (Cobb ≥ 30°), plan for scoliosis surgery, and 2-year follow-up. Results. Two hundred six of 453 patients (45%) completed 2-year follow-up, which is distributed among age groups as follows: 25 to 44 (n = 47), 45 to 64 (n = 121), and 65 to 85 (n = 38) years. The percentages of patients with 2-year follow-up by age group were as follows: 25 to 44 (45%), 45 to 64 (48%), and 65 to 85 (40%) years. These groups had perioperative complication rates of 17%, 42%, and 71%, respectively (P < 0.001). At baseline, elderly patients (65–85 years) had greater disability (ODI, P = 0.001), worse health status (SF-12 physical component score (PCS), P < 0.001), and more severe back and leg pain (NRS, P = 0.04 and P = 0.01, respectively) than younger patients. Mean SRS-22 did not differ significantly at baseline. Within each age group, at 2-year follow-up there were significant improvements in ODI (P ⩽ 0.004), SRS-22 (P ⩽ 0.001), back pain (P < 0.001), and leg pain (P ⩽ 0.04). SF-12 PCS did not improve significantly for patients aged 25 to 44 years but did among those aged 45 to 64 (P < 0.001) and 65 to 85 years (P = 0.001). Improvement in ODI and leg pain NRS were significantly greater among elderly patients (P = 0.003, P = 0.02, respectively), and there were trends for greater improvements in SF-12 PCS (P = 0.07), SRS-22 (P = 0.048), and back pain NRS (P = 0.06) among elderly patients, when compared with younger patients. Conclusion. Collectively, these data demonstrate the potential benefits of surgical treatment for adult scoliosis and suggest that the elderly, despite facing the greatest risk of complications, may stand to gain a disproportionately greater improvement in disability and pain with surgery.

The use of pedicle screw fixation to improve correction in the lumbar spine of patients with idiopathic scoliosis. Is it warranted

Study Design. A retrospective assessment of coronal, sagittal, and axial correction using convex lumbar pedicle screw constructs compared with hook constructs in patients with idiopathic scoliosis. Objective. To determine if pedicle screw constructs can improve coronal, sagittal, and axial correction without increased complications and therefore warrant their use in the lumbar spine. Summary of Background Data. Although hooks have been the traditional fixation choice for posterior scoliosis correction of the lumbar spine, pedicle screws may offer advantages for improved correction of lumbar spinal deformity. Methods. Twenty‐two patients constituted Group A (hooks), in which 17 were double major and five were King Type IV curves. These patients had a minimum follow‐up period of 2 years and an average of one hook per lumbar fusion segment. Twenty‐two patients constituted Group B (screws), in which 20 were double major and two were King Type IV curves. These patients had a minimum follow‐up period of 2 years, and screw configuration consisted of pedicle fixation on the convex side for correction and at times on the concave side for fixation. Results. Pedicle screw fixation constructs had improved lumbar Cobb correction (P < 0.05), lowest instrumented vertebra tilt (P < 0.05), lowest instrumented vertebra translation (P < 0.01), and segmental sagittal alignment from T12 to lowest instrumented vertebra (P < 0.01). There was no significant change in axial rotation using either surgical method. Conclusions. The use of pedicle screw fixation on the convex portion of the lumbar spine in patients with double major idiopathic scoliosis allows for improved correction of the lumbar Cobb measurement, horizontalization and translation of the lowest instrumented vertebra, and improved segmental lordization over the instrumented levels without increased complications.

Improvement of back pain with operative and nonoperative treatment in adults with scoliosis.

OBJECTIVEThe purpose of this study was to assess whether back pain is improved with surgical treatment compared with nonoperative management in adults with scoliosis. METHODSThis is a retrospective review of a prospective, multicentered database of adults with spinal deformity. At the time of enrollment and follow-up, patients completed standardized questionnaires, including the Oswestry Disability Index (ODI) and Scoliosis Research Society 22 questionnaire (SRS-22), and assessment of back pain using a numeric rating scale (NRS) score, with 0 and 10 corresponding to no and maximal pain, respectively. The initial plan for surgical or nonoperative treatment was made at the time of enrollment. RESULTSOf 317 patients with back pain, 147 (46%) were managed surgically. Compared with patients managed nonoperatively, operative patients had higher baseline mean NRS scores for back pain (6.3 versus 4.8; P < 0.001), higher mean ODI scores (35 versus 26; P < 0.001), and lower mean SRS-22 scores (3.1 versus 3.4; P < 0.001). At the time of the 2-year follow-up evaluation, nonoperatively managed patients did not have significant change in the NRS score for back pain (P = 0.9), ODI (P = 0.7), or SRS-22 (P = 0.9). In contrast, at the 2-year follow-up evaluation, surgically treated patients had significant improvement in the mean NRS score for back pain (6.3 to 2.6; P < 0.001), ODI score (35 to 20; P < 0.001), and SRS-22 score (3.1 to 3.8; P < 0.001). Compared with nonoperatively treated patients, at the time of the 2-year follow-up evaluation, operatively treated patients had a lower NRS score for back pain (P < 0.001) and ODI (P = 0.001), and higher SRS-22 (P < 0.001). CONCLUSIONSDespite having started with significantly greater back pain and disability and worse health status, surgically treated patients had significantly less back pain and disability and improved health status compared with nonoperatively treated patients at the time of the 2-year follow-up evaluation. Compared with nonoperative treatment, surgery can offer significant improvement of back pain for adults with scoliosis.

Operative versus nonoperative treatment of leg pain in adults with scoliosis: a retrospective review of a prospective multicenter database with two-year follow-up.

Study Design. Retrospective review of a prospective, multicenter study. Objective. The purpose of this study was to assess the prevalence and severity of leg pain in adults with scoliosis and to assess whether surgery significantly improved leg pain compared with nonoperative management. Summary of Background Data. Patients with adult scoliosis characteristically present with pain. The presence of leg pain is an independent predictor of a patients choice for operative over nonoperative care. Methods. Data were extracted from a prospective, multicenter database for adult spinal deformity. At enrollment and follow-up, patients complete the Oswestry Disability Index (ODI) and assessment of leg pain using the numerical rating scale (NRS) score, with 0 and 10 representing no pain and unbearable pain, respectively. Plan for operative or nonoperative treatment was made at enrollment. The vast majority of adult scoliosis patients seen in our surgical clinics have received nonoperative therapies and are being seen for a surgical evaluation. Patients are counseled regarding operative and nonoperative management options and are in general encouraged to maximize nonoperative treatments. Results. Two hundred eight (64%) of 326 adults with scoliosis had leg pain at presentation (mean NRS score = 4.7). Ninety-six patients with leg pain (46%) were managed operatively and 112 were treated nonoperatively. The operative group had higher baseline mean NRS score for leg pain (5.4 vs. 4.1, P < 0.001) and higher mean ODI (41 vs. 30, P < 0.001). At 2-year follow-up, nonoperative patients had no significant change in ODI or NRS score for leg pain (P = 0.2). In contrast, at 2-year follow-up surgically treated patients had significant improvement in mean NRS score for leg pain (5.4 vs. 2.2, P < 0.001) and ODI (41 vs. 24, P < 0.001). Compared with nonsurgically treated patients, at 2-year follow-up operative patients had lower mean NRS score for leg pain (2.2 vs. 3.8, P < 0.001) and mean ODI (24 vs. 31, P = 0.005). Conclusion. Despite having started with significantly greater leg pain and disability, surgically treated patients at 2-year follow-up had significantly less leg pain and disability than nonoperatively treated patients. Surgical treatment has the potential to provide significant improvement of leg pain in adults with scoliosis.

Is the SRS-22 instrument responsive to change in adult scoliosis patients having primary spinal deformity surgery?

Study Design. Multicenter study. Objective. The purpose of this study is to prospectively analyze responsiveness of the SRS-22 to change at 1 and 2 years following primary surgery. Summary of Background Data. A number of efforts have been directed at validation of the SRS-22 instrument in the setting of adolescent and adult spinal deformity. However, few have extensively analyzed the ability of the instrument to detect change (brought on by surgical treatment) in adult scoliosis patients. Methods. A multicenter prospective series of consecutive adult scoliosis patients (all primary/no revisions) were administered SRS-22, Oswestry Disability Index (ODI)and Short Form-12 (SF-12) questionnaires preoperation and 1 and 2 years postoperation. Fifty-six patients had preoperative, 1-year postoperative, and 2-year postoperative data. Results. The greatest changes from preoperation to 2-year postoperation were the SRS self-image domain followed by SRS total, SRS pain, and ODI scores. SRS pain and function scores significantly (P < 0.05) improved from 1-year to 2-year postoperation. There were not substantial differences in the outcome measures according to age or curve type. All outcome measures except SF-12 mental health showed statistically significant (P < 0.05) improvement from baseline to 2-year follow-up. Conclusion. Based on these 3 outcome tools, the greatest responsiveness to change was demonstrated by the SRS self-image domain followed by SRS total, then SRS pain, then ODI. This suggests that the SRS tool is more responsive than ODI, which is more responsive than SF-12 to change brought on by primary surgical treatment of adult scoliosis patients. Surgical treatment in adult scoliosis significantly improved pain, self-image, and function based on the health-related quality of life measures used in this study.

Changes in Radiographic and Clinical Outcomes With Primary Treatment Adult Spinal Deformity Surgeries From Two Years to Three- to Five-Years Follow-up

Study Design. Retrospective analysis of data entered prospectively into a multicenter database—clinical and radiographic outcomes assessment. Objective. Our hypothesis is that between the 2-year and the 3- to 5-year points surgically treated adult spinal deformity patients will show significant reduction in outcomes by Scoliosis Research Society (SRS), Oswestry Disability Index (ODI), and numerical rating scale back and leg pain scores and will show increasing thoracic kyphosis, loss of lumbar lordosis, and loss of coronal and sagittal balance. Summary of Background Data. Most analyses of primary presentation adult spinal deformity surgery assess 2-year follow-up. However, it is established that in some patients unfavorable events occur between the 2-year and 5-year points. Methods. The cohort of 113 patients entered into a multicenter database with complete preoperative, 2-year, and 3- to 5-year data. All patients who had adult spinal deformity and surgical treatment represented their first reconstruction. Diagnoses were scoliosis (82.5%), kyphosis (10%), and scoliosis and kyphosis combined (7.5%). Outcome measures and basic radiographic parameters (curve size, thoracic and lumbar sagittal plane, coronal and sagittal balance) were assessed at those 3 time intervals. Complications (pseudarthrosis/implant failure, infection, and junctional deformities) were assessed at the 2-year and the 3- to 5-year (mean, 3.76 years) points. Results. The mean major curve Cobb angle (preoperative, 57°; 2-year, 29°; 3–5 year, 26°); thoracic kyphosis T5 to T12 (30°, 31°, 32°) and lumbar lordosis T12 to sacrum (48°, 49°, 51°) did not change from the 2-year to ultimate follow-up. Likewise, coronal and sagittal balance parameters were the same at 2-year and ultimate follow-up. SRS total scores and modified ODI were similar at the 2 year and final follow-up (SRS: 3.89–3.88; ODI: 19–18). Preoperative SRS total score was 3.17. Six patients demonstrated complications at the 2-year point and additional 9patients demonstrated complications at the 3- to 5-year point. Those 9 patients with complications at ultimate follow-up demonstrated significant deterioration in their ODI and SRS scores when compared with the patients who did not have complications at ultimate follow-up. Conclusion. Contrary to our hypothesis, we could not establish deterioration in mean radiographic or clinical outcomes between the 2-year and 3- to 5-year follow-up points when analyzing the group as a whole. However, for the 9 patients who experienced complications between 3- and 5-year follow-up, their outcomes were significantly worse than for the other 104 patients. One should not anticipate an overall radiographic and clinical deterioration of the outcomes of surgically treated primary presentation adult spinal deformity patients in this studied time interval. However, close to 10% of patients will experience a new complication at the 3- to 5-year point, most commonly implant failure/nonunion and/or junctional kyphosis, which will negatively effect the patient-reported outcome.

The problems and limitations of applying evidence-based medicine to primary surgical treatment of adult spinal deformity.

Study Design. Assessment of peer-reviewed literature and personal experience with publications and grant organization. Objective. This is an analysis of the current status of evidence-based medicine for primary adult spinal deformity to answer the question of whether surgical treatment benefits patients. Summary of Background Data. A limited number of evidence-based studies have been performed for primary adult scoliosis and spinal deformity surgery. None of these studies is ideal. Methods. This is an assessment of current literature and study group methodology in an attempt to provide an evidence-based medicine approach for the study of primary presentation adult scoliosis and related spinal deformity. Results. Many reasonable studies exist; however, there are no current definitive studies that answer the question posed above. There are many obstacles, both financial and organizational, to producing an “ideal” study. Most smaller studies suggest that surgical treatment of primary adult scoliosis benefits the patient. However, there is no multicenter prospective randomized study to answer this question. Conclusion. A multicenter funded study is needed to answer appropriate questions.

Posterior arthrodesis in the skeletally immature patient : Assessing the risk for crankshaft : is an open triradiate cartilage the answer?

Study Design. Thirty-three skeletally immature patients younger than 12 years of age and having posterior arthrodesis and evidence of solid posterior fusion without “adding on” were retrospectively reviewed. All patients had a minimum of 5 years of follow-up. Objectives. To ascertain factors associated with crankshaft and to determine how accurate a marker the triradiate cartilage was. Summary of Data. All patients had Risser Stage 0 curves and all of the girls were premenarchal preoperatively. The average age was 9 years 3 months (range, 2 years-11 years 11 months). Preoperative diagnoses consisted of 14 idiopathic, 11 congenital, five dysplastic, and three neuromuscular etiologies. Methods. Preoperatively, within 3 months after surgery, and at 2-year, 5-year, and final postoperative follow-up, the following radiographic parameters were reviewed: coronal Cobb, apical vertebral rotation, apical vertebral translation, rib vertebral angle difference, and trunkshift. Results. The triradiate cartilage was open in 24 patients at the time of operation. Of those 24, only nine (37.5%) had documented proof of crankshaft. Patients with closed triradiate cartilage had no significant postoperative increase in radiographic parameters (0 of 9). The subgroup of patients with idiopathic scoliosis had an average age of 11 years 3 months (range, 9 years 2 months-11 years 11 months). Five of 14 patients had an open triradiate cartilage. All were followed up to skeletal maturity. None had significant progression in postoperative radiographic parameters. Conclusion. This study did not find an open triradiate cartilage to be an absolute prognostic indicator for the occurrence of crankshaft. Additional refinement of markers of maturity are needed to determine who requires anterior arthrodesis.

Neurogenic motor evoked potentials: a prospective comparison of stimulation methods in spinal deformity surgery.

Neurogenic motor evoked potentials (NMEPs) elicited by spinal cord stimulation via the spinous processes (SP-NMEP) have been widely accepted as a sensitive method of monitoring motor tract function. SP-NMEP requires additional surgical dissection as well as electrodes within the wound, making the method somewhat inconvenient. A less invasive percutaneous method of spinal cord stimulation (PERC-NMEP) has more recently been described. We prospectively compared the SP-NMEP and PERC-NMEP methods in 184 patients undergoing 225 surgical procedures. Although SP-NMEP responses were more readily obtainable than PERC-NMEP, the reliability of the two methods was not significantly different. Both methods were found to be sensitive to neurologic deficit. The present study suggests that when responses are obtained, the percutaneous method is reliable enough to obviate the spinous process method of monitoring the motor function of the spinal cord.