Faculty Bibliography

BACKGROUND/AIMS: Surgical techniques for effective high-grade spondylolisthesis (HGS) remain controversial. This study aims to evaluate radiographic/clinical outcomes in HGS patients treated using modified "Reverse Bohlman" (RB) technique. METHODS: Review of consecutive HGS patients undergoing RB at a single university-center from 2006 to 2013. Clinical, surgical, radiographic parameters collected. RESULTS: Six patients identified: five with L5-S1 HGS with L4-L5 instability and one had an L4-5 isthmic spondylolisthesis and grade 1 L5-S1 isthmic spondylolisthesis. Two interbody graft failures and one L5-S1 pseudoarthrosis. Postoperative improvement of anterolisthesis (62.3% vs. 49.6%, p = 0.003), slip angle (10 vs. 5 degrees , p = 0.005), and lumbar lordosis (49 vs. 57.5 degrees , p = 0.049). CONCLUSIONS: RB technique for HGS recommended when addressing adjacent level instability/slip.

PURPOSE: The aim of this study is to report and quantify the associated factors for morbidity and mortality following surgical management of cervical spondylotic myelopathy (CSM). METHODS: The Nationwide Inpatient Sample (NIS) database was use to retrospectively review all patients over 25 years of age with a diagnosis of CSM who underwent anterior and/or posterior cervical fusion or laminoplasty between 2001 and 2010. The main outcome measures were total procedure-related complications and mortality. Multivariate regression analysis was used to identify demographic, comorbidity, and surgical parameters associated with increased morbidity and mortality risk [reported as: OR (95 % CI)]. RESULTS: A total of 54,348 patients underwent surgical intervention for CSM with an overall morbidity rate of 9.83 % and mortality rate of 0.43 %. Comorbidities found to be associated with an increased complication rate included: pulmonary circulation disorders [6.92 (5.91-8.12)], pathologic weight loss [3.42 (3.00-3.90)], and electrolyte imbalance [2.82 (2.65-3.01)]. Comorbidities found to be associated with an increased mortality rate included: congestive heart failure [4.59 (3.62-5.82)], pulmonary circulation disorders [11.29 (8.24-15.47)], and pathologic weight loss [5.43 (4.07-7.26)]. Alternatively, hypertension [0.56 (0.46-0.67)] and obesity [0.36 (0.22-0.61)] were found to confer a decreased risk of mortality. Increased morbidity and mortality rates were also identified for fusions of 4-8 levels [morbidity: 1.55 (1.48-1.62), mortality: 1.80 (1.48-2.18)] and for age >65 years [morbidity: 1.65 (1.57-1.72), mortality: 2.74 (2.25-3.34)]. An increased morbidity rate was found for posterior-only [1.55 (1.47-1.63)] and combined anterior and posterior fusions [3.20 (2.98-3.43)], and an increased mortality rate was identified for posterior-only fusions [1.87 (1.40-2.49)]. Although revision fusions were associated with an increased morbidity rate [1.81 (1.64-2.00)], they were associated with a decreased rate of mortality [0.24 (0.10-0.59)]. CONCLUSION: The NIS database was used to provide national estimates of morbidity and mortality following surgical management of CSM in the United States. Several comorbidities, as well as demographic and surgical parameters, were identified as associated factors.

BACKGROUND: Few studies have provided nationwide estimates of patient characteristics and procedure-related complications, or examined postsurgical outcomes for patients with cervical spondylotic myelopathy (CSM) comparatively with respect to surgical approach. The objective of this study is to identify patients at risk for morbidity and mortality directly related with the selected approach, report an overall nation-wide complication rate for each approach against which surgeons can compare themselves, and direct future research to improve patient outcomes. METHODS: Patients surgically treated for CSM were retrospectively identified using ICD-9-CM codes from the Nationwide Inpatient Sample (NIS) database. Four cohorts were compared for demographics and hospital system-related data: anterior (ACDF, ACCF), posterior decompression without fusion, decompression with posterior fusion, and combined anterior-posterior. Multivariate analysis was also used to determine the odds ratio of morbidity and mortality among the cohorts. RESULTS: 54,416 discharges were identified between 2001 and 2010: 34,400 anterior, 9,014 decompression procedures without fusion, 8,741 decompression procedures with posterior fusion, and 2,261 combined anterior-posterior. Groups were statistically different with respect to age, length of hospital stay, mortality, and complications. Groups were statistically different for Deyo score except between posterior decompression only and combined approaches. Using multivariate analysis and adjusting for covariates, the combined (2.74[2.18-3.44]) and laminectomy (1.22[1.04-1.44]) cohorts had an increased risk of mortality when compared to anterior alone. CONCLUSION: These findings are the first to determine the rates and odds of perioperative risks directly related to combined anterior-posterior procedures. This study provides clinically useful data for surgeons to educate patients and direct future research to improve patient outcomes.

STUDY DESIGN.: Multicenter, retrospective study. OBJECTIVE.: To compare the outcomes of three surgical treatments for congenital spinal deformity due to a hemivertebra. SUMMARY OF BACKGROUND DATA.: Congenital anomalies of the spine can cause significant and progressive scoliosis and kyphosis. Their management may be challenging and controversy remains over the 'best' surgical treatment. METHODS.: A multicenter retrospective study of patients with congenital spinal deformity due to 1 or 2 level hemivertebra(e) was performed. The surgical treatments included hemiepiphysiodesis or in situ fusion (group 1), instrumented fusion without hemivertebra excision (group 2), or instrumented hemivertebra excision (group 3). RESULTS.: Seventy-six patients with minimum 2-year follow-up were evaluated. The mean age was 8 years (range: 1-18). The hemivertebra were fully segmented, nonincarcerated (67%), incarcerated (1%), and semisegmented (32%). There were 65 patients with single hemivertebra and 11 patients with double hemivertebra. There were 14 (18.4%) group 1, 20 (26.3%) group 2, and 42 (55.3%) group 3 patients. Group 1 (37 +/- 14 degrees ) and group 3 (35 +/- 26 degrees ) patients had smaller preoperative curves than group 2 patients (55 +/- 26 degrees ) (P < 0.01). Group 3 had better percent correction at 2 years than groups 1 and 2 (P < 0.001). Group 3 had shorter fusion (P = 0.001), less estimated blood loss (EBL, P = 0.03), and a trend toward shorter operative times than group 2 (P = 0.10). The overall complication rate for the entire group was 30% group 1 (23%), group 2 (17%), and group 3 (44%) (P = 0.09). CONCLUSION.: While hemivertebra resection for congenital scoliosis had a higher complication rate than either hemiepiphysiodesis/in situ fusion or instrumentated fusion without resection, posterior hemivertebra resection in younger patients resulted in better percent correction than the other two techniques

STUDY DESIGN: Multicenter analysis of 2 groups of patients surgically treated for Lenke 5C adolescent idiopathic scoliosis (AIS). OBJECTIVE: Compare patients with Lenke 5C scoliosis surgically treated with anterior spinal fusion with dual rod instrumentation and anterior column support with patients surgically treated with posterior release and pedicle screw instrumentation. SUMMARY OF BACKGROUND DATA: Treatment of single, structural, lumbar, and thoracolumbar curves in patients with AIS has been the subject of some debate. Advocates of the anterior approach assert that their technique spares posterior musculature and may save distal fusion levels, and that with dual rods and anterior column support the issues with nonunion and kyphosis have been obviated. Advocates of the posterior approach assert that with the change to posterior pedicle screw based instrumentation that correction and levels are equivalent, and the posterior approach avoids the issues with nonunion and kyphosis. This report directly compares the results of posterior versus anterior instrumented fusions in the operative treatment of adolescent idiopathic Lenke 5C curves. METHODS: We analyzed 62 patients with Lenke 5C based on radiographic and clinical data at 2 institutions: 31 patients treated with posterior, pedicle-screw instrumented fusions at 1 institution (group PSF); and 31 patients with anterior, dual-rod instrumented fusions at another institution (group ASF). Multiple clinical and radiographic parameters were evaluated and compared. RESULTS: The mean age, preoperative major curve magnitude, and preoperative lowest instrumented vertebral (LIV) tilt were similar in both groups (age: PSF = 15.5 years, ASF = 15.6 years; curve size: PSF = 50.3 degrees +/- 7.0 degrees , ASF = 49.0 degrees +/- 6.6 degrees ; LIV tilt: PSF = 27.5 degrees +/- 6.5 degrees , ASF = 27.8 degrees +/- 6.2 degrees ). After surgery, the major curve corrected to an average of 6.3 degrees +/- 3.2 degrees (87.6% +/- 5.8%) in the PSF group, compared with 12.1 degrees +/- 7.4 degrees (75.7% +/- 14.8%) in the ASF group (P < 0.01). At final follow-up, the major curve measured 8.0 degrees +/- 3.0 degrees (84.2% +/- 5.8% correction) in the PSF group, compared with 15.9 degrees +/- 9.0 degrees (66.6% +/- 17.9%) in the ASF group (P = 0.01). This represented a loss of correction of 1.7 degrees +/- 1.9 degrees (3.4% +/- 3.7%) in the PSF group, and 3.8 degrees +/- 4.2 degrees (9.4% +/- 10.7%) in the ASF group (P = 0.028). The LIV tilt decreased to 4.1 degrees +/- 3.4 degrees after surgery in the PSF group, and 4.5 degrees +/- 3.7 degrees in the ASF group. At final follow-up, the LIV tilt was 5.1 degrees +/- 3.5 degrees in the PSF group, and 4.5 degrees +/- 3.7 degrees in the ASF group. EBL was identical in both groups, and length of hospital stay was significantly (P < 0.01) shorter in the PSF group (4.8 vs. 6.1 days). There were no complications in either group which extended hospital stay or required an unplanned second surgery. CONCLUSION: At a minimum of 2-year follow-up, adolescents with Lenke 5C curves demonstrated statistically significantly better curve correction, less loss of correction over time, and shorter hospital stays when treated with a posterior release with pedicle screw instrumented fusion compared with an anterior instrumented fusion with dual rods for similar patient populations.

STUDY DESIGN: Case series. OBJECTIVE: To examine a consecutive series of surgically treated Scheuermann kyphosis that had a posterior only procedure with segmental pedicle screw fixation and segmental Ponte osteotomies. SUMMARY OF BACKGROUND DATA: The gold standard for surgical treatment of Scheuermann kyphosis (a rigid kyphosis associated with wedged vertebral bodies occurring in late childhood or adolescence) has been combined anterior and posterior approach surgery. Alberto Ponte has advocated a posterior-only procedure with posterior column shortening via segmental osteotomies, but his procedure has not been widely accepted owing to concerns that without anterior column support there would be a risk of correction loss and/or instrumentation failure. With the advent of improved spinal instrumentation and fixation with thoracic pedicle screws, the Ponte procedure may offer an advantage over anterior/posterior reconstruction. METHODS: The study prospectively enrolled 17 consecutive patients with Scheuermann kyphosis who were treated with the Ponte procedure by the senior surgeon at one institution. Standardized radiographic analysis was performed and included full-length coronal and sagittal radiographs preoperatively, postoperatively, and at final follow-up. Analysis also included the correction obtained through the most severe, wedged segments of the deformity by the osteotomies. RESULTS: Seventeen patients had the Ponte procedure satisfactorily performed. No patient needed an anterior approach to achieve sufficient correction or fusion. There were no reoperations for nonunion or instrumentation failure. Correction of the instrumented levels was 61% and of worst Cobb was mean 49%. The apex of the deformity was measured over the most deformed 3 to 7 wedged segments. The average correction across the apex was 9.3 degrees per osteotomy (range 5.9 to 15). No patient lost more than 4 degrees of correction through their instrumented and fused levels. There were no neurologic complications. There was one late infection with a solid fusion treated with instrumentation removal and intravenous antibiotics. CONCLUSIONS: Using thoracic pedicle screw instrumentation as the primary anchor, the Ponte procedure was successfully performed in 17 consecutive patients for Scheuermann kyphosis with no exclusions for the size or rigidity of the kyphosis. Results were as good as anterior/posterior historical controls with excellent correction and minimal loss of correction at final follow-up. This procedure avoids the morbidity and extended operative time attributed to the anterior approach. LEVEL OF EVIDENCE: Therapeutic study, level IV [case series (no, or historical, control group)].

STUDY DESIGN: With institutional review board approval, prospective data were collected during fluoroscopically guided pedicle screw placement. OBJECTIVE: To estimate a surgeon's radiation exposure with all screw constructs during surgery to repair idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: To our knowledge, there is no established consensus regarding the safety of radiation exposure during fluoroscopically guided procedures. METHODS: A surgeon was outfitted intraoperatively with a thermoluminescent dosimeter to estimate radiation exposure to his whole body and thyroid gland. RESULTS: The index surgeon is projected to receive 13.49 mSv of whole body ionizing radiation and 4.31 mSv of thyroid gland irradiation annually. The National Council on Radiation Protection's current recommendations set lifetime dose equivalent limits for classified workers (radiologists) at 10 mSv per year of life and at 3 mSv for nonclassified workers (spinal surgeons). At the levels estimated, a surgeon beginning his/her career at age 30 years would exceed the lifetime limit for nonclassified workers in less than 10 years. The National Council on Radiation Protection limits the single-year maximum safe dosage to the thyroid to 500 mSv; the yearly exposure estimated here is significantly less. CONCLUSIONS: The spinal surgeon's intraoperative radiation exposure may be unacceptable. Spinal surgeons should be considered classified workers and monitored accordingly. Methods to lower radiation dosage seem strongly indicated.

STUDY DESIGN: Author experience and literature review. OBJECTIVES: To investigate the spectrum of adult kyphosis and to discuss the various surgical and nonsurgical treatment options. SUMMARY OF BACKGROUND DATA: Kyphosis with its various etiologies and associated pathophysiologies has been discussed in the literature for many decades. The nonsurgical treatment primarily consists of symptom reduction via physical therapy and has not changed significantly for decades. The surgical treatment, however, has changed dramatically. A decade ago, most large kyphotic deformities required anterior and posterior procedures. With the advent of numerous posterior osteotomy techniques and pedicle fixation, most of these deformities are now treated via posterior methods only. METHODS: Using literature review and the author's experience, kyphosis and its characteristics will be discussed. Important details pertinent to presurgical planning and execution of surgical will be discussed. Three cases will be presented to illustrate the surgical treatment options for three qualitatively different kyphotic deformities. RESULTS: Flexible kyphotic deformities may respond well to aggressive facetectomies and cantilever corrections. Multisegmental osteotomies may be most appropriate for long sweeping deformities. Fixed, sharply, angulated deformities may respond best to pedicle subtraction osteotomies or vertebral column resections. CONCLUSION: Segmental pedicle screw fixation coupled with one of four posterior osteotomy/resection techniques can be used to address most sagittal plain deformities. Careful application of these techniques is important. Smith-Petersen and Ponte osteotomies are most appropriate for long sweeping deformities with mobile anterior columns. Pedicle subtraction osteotomies and vertebral column resections are most appropriate for fixed, sharply angulated spinal deformities. The successful application of these techniques is dependent on accurate preoperative evaluation of the structural properties of the kyphosis and meticulous execution of the surgical technique.