Ames, Christopher Pearson

BACKGROUND AND OBJECTIVES: The purpose of this study was to analyze the impact of patient-specific rods on mechanical complications after adult thoracolumbar spinal deformity surgery. METHODS: A consecutive series was analyzed of 200 adult thoracolumbar spinal deformity patients. Half of the patients (n = 100) had surgery just before implementing patient-specific rods, and the other 100 patients had surgery immediately after adoption of patient-specific rods. All patients had instrumented fusions from the thoracic spine to the pelvis. Mechanical complications were defined as rod fracture, proximal junctional kyphosis, proximal junctional failure (revision surgery requiring proximal fusion extension), and/or revision surgery for rod fracture or pseudoarthrosis. Minimum follow-up was 2 years. RESULTS: A total of 200 patients were included with a median (IQR) age of 68 (61, 73), body mass index of 28 (25, 32), and 73% were female. The patients with patient-specific rods compared with those without had less preoperative kyphosis (39° vs 44°, P = .01), a higher median number of rods (4 vs 2, P = .04), more often a combined anterior-posterior approach (61% vs 46%, P = .047), more commonly a upper instrumented vertebra vertebroplasty (67% vs 45% P = .003), and postoperatively had less thoracic kyphosis (45% vs 49%, P = .02). Patient-specific rod patients had a lower rate of mechanical complications (29% vs 47%, P = .01), a lower rate of rod fracture (3% vs 16%, P = .003), and shorter operative times (215 minutes vs 250 minutes, P = .04). On multivariable analysis, the only 2 independent predictors of reducing the rate of mechanical complications were the utilization of patient-specific rods (odds ratio 0.47, P = .013, CI 0.26-0.85) and lower postoperative thoracic kyphosis (odds ratio 1.02, P = .04, CI 1.00-1.05). CONCLUSION: In a consecutive series of adult thoracolumbar spinal deformity patients, patient-specific rods reduced the odds of mechanical complications by over 50%. Adoption of patient-specific rods should be considered to optimize patient outcomes after adult spinal deformity surgery.

BACKGROUND AND OBJECTIVES: En bloc spondylectomies are essential for controlling malignant spinal tumors, but existing classification systems are often complex and impractical. This study introduces the Column, Line-of-Sight, Margins, Ring (CLiMR) framework, a novel system simplifying and standardizing en bloc spondylectomy planning and classification. METHODS: A retrospective review of patients who underwent single- or multistage en bloc spinal tumor resections was conducted at a single academic center (October 2019-December 2024). The CLiMR framework assigns scores to 4 components: Column (osteotomies/diskectomies for tumor release), Line-of-Sight (approach for circumferential access), Margin (adjacent structures sacrificed), and Ring (size of the vertebral ring window for safe delivery of neural tissue). Scores were applied using operative notes and imaging. RESULTS: Column scores ranged from 0.5 to 4.5. Of the patients included, 40.9% underwent sagittal split osteotomies, 22.7% radical diskectomies, 18.2% horizontal osteotomies, and the remaining 18.2% combinations of previous osteotomies . A posterior-only approach (Line-of-Sight score = 1) was used in 45.4% of cases, whereas 45.4% required a multistage approach (score = 2). Margin scores reflected increasing morbidity: 31.8% (n = 7) involving chest wall/pleura resection (grade 3), 40.9% (n = 9) requiring eloquent nerve sacrifice (grade 6), and 9.1% (n = 2) necessitating limb sacrifice (grade 7). The majority (86.4%, n = 19) of ring scores were grade 1, requiring laminectomies/facetectomies. The mean CLiMR score was 9.36 ± 2.43, with higher scores correlating with longer hospital stays (R = 0.64, P = .0012), longer case durations (R = 0.61, P = .0023), and increased blood loss (R = 0.40, P = .067). Patients with local recurrence, positive margins, or complications trended toward greater CLiMR scores. CONCLUSION: The CLiMR framework provides a novel, user-friendly method for planning and communicating en bloc spondylectomies. By addressing technical complexities and morbidity, CLiMR enables standardized assessment, facilitates surgical decision-making, and supports future research. This study demonstrates feasibility and lays the foundation for future validation studies.

OBJECTIVE The aim of this study was to determine predictors of the minimum clinically important difference (MCID) in the Neck Disability Index (NDI) following cervical spinal deformity surgery. METHODS A retrospective review was performed of a prospective, multicenter adult cervical spinal deformity database. All patients had baseline and 1-year NDI scores. Patients met MCID with an improvement of NDI by 7 points between baseline and 1 year, as previously established. Baseline demographics, comorbidities, and both baseline and 1-year spinopelvic parameters were evaluated for statistical significance in a univariate logistic regression analysis. Significant variables, in addition to baseline NDI, were analyzed in a multivariable logistic regression model by backward selection with Akaike information criterion minimization. RESULTS A total of 122 patients were included with a median age of 62 (IQR 56, 69) years; 62% of patients were female. Of the 122 patients, 72 (59%) achieved NDI MCID at 1 year. Predictors of achieving MCID on univariate analysis included a lower Charlson Comorbidity Index (CCI) total score (OR 0.70, p = 0.03), depression as a comorbidity (OR 2.9, p = 0.02), lower C2 tilt at the 1-year follow-up (OR 0.92, p = 0.02), and a greater difference between 1-year postoperative C2–7 sagittal vertical axis (SVA) and preoperative C2–7 SVA (OR 0.98, p = 0.0495). On multivariable logistic regression analysis, predictors of achieving MCID included a lower CCI (OR 0.62, p = 0.03), depression as a comorbidity (OR 3.1, p = 0.059), a greater change in C2–7 SVA at the 1-year follow-up compared with baseline (OR 0.97, p = 0.055), and baseline NDI (OR 1.02, p = 0.24) with an area under the curve of 0.74. CONCLUSIONS The best-fit multivariable model included higher baseline NDI, a greater change in C2–7 SVA, patient-reported baseline depression, and lower CCI as important factors in predicting NDI MCID.

OBJECTIVE The purpose of this study was to evaluate whether level selection for a three-column osteotomy (3CO) impacts cervical deformity correction outcomes, including neurological, radiographic, and patient-reported outcomes. METHODS A retrospective review was performed of patients who underwent a cervical or upper thoracic 3CO for cervical deformity correction by the senior author from 2008 to 2024. Collected outcome measures included neurological outcomes, mechanical complication rates, spinopelvic alignment, and patient-reported outcomes. The minimum follow-up was 1 year. RESULTS One hundred fifteen patients were identified who underwent a cervical or upper thoracic 3CO for cervical deformity correction, of whom 77 met inclusion criteria for this study with a minimum follow-up of 1 year. The median age was 66 years, the median BMI was 27, and 43% of patients were male. Sixteen patients underwent a 3CO at the C7–T1 levels and 61 patients at T2–6 levels. Patients who underwent C7–T1 3CO were more likely to experience a new postoperative neurological deficit compared with those who underwent T2–6 3CO (56% vs 18%, p = 0.004), had less correction in their T1 slope (6° vs 18°, p = 0.027), had less correction in C2–T4 sagittal vertical axis (2.8 cm vs 4.9 cm, p = 0.043), and had a worse Neck Disability Index (NDI) score at 1 year compared with baseline (an increase of 7 vs a decrease of 12, p = 0.033). CONCLUSIONS Cervical deformity patients who underwent a 3CO at C7–T1 had a higher rate of postoperative neurological deficits, less radiographic correction, and worse NDI scores at 1 year compared with patients who underwent a 3CO from T2 to T6. Although 3CO level selection is multifactorial and patient specific, surgeons should consider a 3CO level caudal to T1 when feasible.

OBJECTIVE The purpose of this study was to evaluate the risks and benefits of removing painful pelvic/iliac screws in spine fusion surgery patients. METHODS A retrospective review identified patients who had traditional iliac and S2-alar-iliac (S2AI) screws removed for pain. The minimum follow-up was 24 months. RESULTS Fifty-two patients (75% women) were included with a mean age of 63 years, BMI of 28, and follow-up of 65 months. Most of the removed screws were S2AI (83%) compared with traditional iliac screws (17%). Forty-three patients (83%) had improvement in their pelvic screw related–pain following removal. Eight patients (15%) experienced lumbosacral mechanical complications following pelvic screw removal including sacral fracture (n = 3, 6%) and/or L4–5 or L5–S1 rod fracture (n = 7, 13%). On multivariable analysis, risk factors for mechanical complications following pelvic screw removal included a longer fusion construct (OR 1.34, p = 0.035), greater postoperative L4–S1 lordosis (OR 1.14, p = 0.04, ideal cutoff > 40°), and lack of bone morphogenetic protein (BMP; OR 0.03, p = 0.02). Ten patients (19%) underwent subsequent SI joint fusion following pelvic screw removal, and higher standing pelvic incidence (OR 1.10, p = 0.03) was the only independent predictor of SI fusion. CONCLUSIONS Removal of painful pelvic screws resulted in a high rate of postoperative pain relief, albeit with a risk of lumbosacral mechanical complications and subsequent SI joint fusion. Patients at risk for lumbosacral mechanical complications following pelvic screw removal included those with longer fusion constructs, more lordosis from L4 to S1 (> 40°), and lack of BMP. Patients at risk for receiving an instrumented SI joint fusion following pelvic screw removal included those with a higher pelvic incidence.

OBJECTIVE The purpose of this study was to determine risk factors for distal junctional failure (DJF) following three-column osteotomy (3CO) for the correction of cervical deformity. METHODS A retrospective review was performed of patients who underwent a cervical or upper thoracic 3CO for cervical deformity correction by the senior author from 2008 to 2023. The main outcome of interest was DJF, defined as revision surgery with extension of the distal end of the fusion construct. Patients were excluded if the lowest instrumented vertebra (LIV) was the sacrum/pelvis, and if patients had prior autofusion throughout the distal part of the spine to the sacrum (e.g., ankylosing spondylitis). The minimum follow-up duration was 1 year. RESULTS One hundred fourteen patients were identified who underwent a cervical or upper thoracic 3CO for cervical deformity correction, 41 of whom met inclusion criteria for this study. The median patient age was 66 years, median BMI was 27, and 61% were male. Ten patients (24%) experienced DJF, requiring reoperation and distal extension of the construct to the pelvis in 9 cases and to L1 in 1 case. On univariable analysis, patients who experienced DJF compared with those who did not were more likely to be female (80% vs 35%, p = 0.007), had lower LIV Hounsfield units (HUs; 127 vs 167, p = 0.041), were less likely to have an LIV in a small autofused segment (10% vs 45%, p = 0.02), had an LIV that was closer to the first lordotic level (one level above vs three, p = 0.043), and had a longer length of fusion (17 vs 13 levels, p = 0.033). A stepwise multivariable regression model showed that having an LIV closer to the first lordotic vertebra was the only statistically significant predictor of DJF (OR 0.49, p = 0.013) and low LIV HUs did not reach statistical significance (OR 0.97, p = 0.09). CONCLUSIONS Patients with cervical deformity undergoing a 3CO are at higher risk for DJF with constructs terminating near the first lordotic vertebra. While LIV selection is complex and patient specific, choosing an LIV at least two levels above the first lordotic vertebra may help prevent DJF.

OBJECTIVE Correction of mild flexible cervical deformity (CD) via the posterior approach has been described with and without the use of posterior osteotomies (POs), despite a lack of clarity regarding their necessity or risks. The purpose of this study was to determine whether the use of POs when correcting mild flexible CD leads to improved clinical or radiographic outcomes, as well as defining the relative risks in utilizing them. METHODS A prospective multicenter registry of operative CD patients was analyzed. Inclusion criteria were cervical kyphosis > 10°, cervical scoliosis > 10°, cervical sagittal vertical axis (cSVA) > 4 cm, or chin-brow vertical angle > 25°. Mild deformity was defined by a cSVA of 3–5 cm and/or kyphosis < 15°. Flexibility was defined by a C2–7 angular change > 5° on preoperative flexion/extension radiographs. Patients who received a posterior column osteotomy (PCO) (Ames grades 1 and 2) were compared with patients who did not undergo a PCO (noPCO) as well as those who underwent a three-column osteotomy (3CO) (Ames grades 3–6). RESULTS Ninety-five patients (33 PCO, 49 noPCO, 13 3CO) met the inclusion criteria. Both the number of levels fused (9.2 vs 7.7, p = 0.001) and the estimated blood loss (EBL) (1027 vs 486 mL, p = 0.012) were higher in the PCO cohort. Patients in the noPCO group were more likely to have a cervical apex of kyphosis (71.1%, p = 0.046), while those undergoing 3COs were more likely to have a thoracic apex (58.3%, p = 0.005). Preoperative cSVA (PCO vs noPCO: 45.4 vs 37.9 cm, p = 0.084), T1 slope (32.5° vs 29.6°, p = 0.376), C2–7 lordosis (−8.9° vs −9.2°, p = 0.942), and modified Japanese Orthopaedic Association (mJOA) score (13.4 vs 13.5, p = 0.854) were similar; however, both Neck Disability Index (NDI) (55.6 vs 42, p = 0.002) and numeric rating scale (NRS) neck (7.2 vs 5.8, p = 0.028) scores were higher in the PCO group before surgery. When adjusting for the use of an anterior approach, there was no significant difference in 1-year postoperative cSVA (35.7 and 35.6 cm, respectively; p = 0.969), C2–7 lordosis (13.7° and 10.1°, respectively; p = 0.393), and patient-reported outcome measures (NRS, NDI, and mJOA) between the PCO and noPCO groups. Two-year radiographic outcomes were largely similar, except for C2 slope, which was higher in the PCO group (29.1° vs 18°, p = 0.026). The overall complication rates progressively increased with more complex osteotomy use (noPCO 68.8% vs PCO 71.9% vs 3CO 75%) but did not reach significance (p = 0.063). CONCLUSIONS The use of POs for mild flexible adult CD may not be necessary to achieve desirable radiographic correction. They are associated with greater EBL and fusion burden. Further studies are needed to fully delineate the risks of adverse events for various types of osteotomies.

OBJECTIVE The aim of this study was to analyze risk factors and avoidance techniques for proximal junctional kyphosis (PJK) and proximal junctional failure (PJF) in the upper thoracic spine with an emphasis on bone mineral density (BMD) as estimated by Hounsfield units (HU). METHODS A retrospective chart review identified patients at least 50 years of age who underwent instrumented fusion extending from the pelvis to an upper instrumented vertebra (UIV) between T1 and T6 and had a preoperative CT, pre- and postoperative radiographs, and a minimum follow-up of 12 months. HU were measured in the UIV, the vertebral body cephalad to the UIV (UIV+1), and the L3 and L4 vertebral bodies. Numerous perioperative variables were collected, including basic demographics, smoking and steroid use, preoperative osteoporosis treatment, multiple frailty indices, use of a proximal junctional tether, UIV soft landing, preoperative dual-energy x-ray absorptiometry, spinopelvic parameters, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, lumbar lordosis distribution, and postoperative spinopelvic parameters compared with age-adjusted normal values. RESULTS Eighty-one patients were included in the study (21 men and 60 women) with a mean (SD) age of 66 years (6.9 years), BMI of 29 (5.5), and follow-up of 38 months (25 months). Spinal fusion constructs at the time of surgery extended from the pelvis to a UIV of T1 (5%), T2 (15%), T3 (25%), T4 (33%), T5 (21%), and T6 (1%). Twenty-seven patients (33%) developed PJK and/or PJF; 21 (26%) had PJK and 15 (19%) had PJF. Variables associated with PJK/PJF with p < 0.05 were included in the multivariable analysis, including HU at the UIV/UIV+1, HU at L3/L4, DXA femoral neck T-score, UIV screw tip distance to the superior endplate, UIV pedicle screw/pedicle diameter ratio, and postoperative lumbar lordosis distribution. Multivariable analysis (area under the curve = 0.77) demonstrated HU at the UIV/UIV+1 to be the only independent predictor of PJK and PJF with an OR of 0.96 (p = 0.005). Patients with < 147 HU (n = 27), 147–195 HU (n = 27), and > 195 HU (n = 27) at the UIV/UIV+1 had PJK/PJF rates of 59%, 33%, and 7%, respectively. CONCLUSIONS In patients with upper thoracic–to-pelvis spinal reconstruction, lower HU at the UIV and UIV+1 were independently associated with PJK and PJF, with an optimal cutoff of 159 HU that maximizes sensitivity and specificity.

ObjectStabilization of the atlantoaxial complex has proven to be very challenging. Because of the high mobility of the C1–2 motion segment, fusion rates at this level have been substantially lower than those at the subaxial spine. The set of potential surgical interventions is limited by the anatomy of this region. In 2001 Jürgen Harms described a novel technique for individual fixation of the C-1 lateral mass and the C-2 pedicle by using polyaxial screws and rods. This method has been shown to confer excellent stability in biomechanical studies. Cadaveric and radiographic analyses have indicated that it is safe with respect to osseous and vascular anatomy. Clinical outcome studies and fusion rates have been limited to small case series thus far. The authors reviewed the multicenter experience with 102 patients undergoing C1–2 fusion via the polyaxial screw/rod technique. They also describe a modification to the Harms technique.MethodsOne hundred two patients (60 female and 42 male) with an average age of 62 years were included in this analysis. The average follow-up was 16.4 months. Indications for surgery were instability at the C1–2 level, and a chronic Type II odontoid fracture was the most frequent underlying cause. All patients had evidence of instability on flexion and extension studies. All underwent posterior C-1 lateral mass to C-2 pedicle or pars screw fixation, according to the method of Harms. Thirty-nine patients also underwent distraction and placement of an allograft spacer into the C1–2 joint, the authors' modification of the Harms technique. None of the patients had supplemental sublaminar wiring.ResultsAll but 2 patients with at least a 12-month follow-up had radiographic evidence of fusion or lack of motion on flexion and extension films. All patients with an allograft spacer demonstrated bridging bone across the joint space on plain x-ray films and computed tomography. The C-2 root was sacrificed bilaterally in all patients. A postoperative wound infection developed in 4 patients and was treated conservatively with antibiotics and local wound care. One patient required surgical debridement of the wound. No patient suffered a neurological injury. Unfavorable anatomy precluded the use of C-2 pedicle screws in 23 patients, and thus, they underwent placement of pars screws instead.ConclusionsFusion of C1–2 according to the Harms technique is a safe and effective treatment modality. It is suitable for a wide variety of fracture patterns, congenital abnormalities, or other causes of atlantoaxial instability. Modification of the Harms technique with distraction and placement of an allograft spacer in the joint space may restore C1–2 height and enhance radiographic detection of fusion by demonstrating a graft–bone interface on plain x-ray films, which is easier to visualize than the C1–2 joint.