Can We Rely on Prophylactic Two-Level Vertebral Cement Augmentation in Long-Segment Adult Spinal Deformity Surgery to Reduce the Incidence of Proximal Junctional Complications?

Background and Objectives: Proximal junctional kyphosis (PJK) and failure (PJF), the most prevalent complications following long-segment thoracolumbar fusions for adult spinal deformity (ASD), remain lacking in defined preventive measures. We studied whether one of the previously reported strategies with successful results-a prophylactic augmentation of the uppermost instrumented vertebra (UIV) and supra-adjacent vertebra to the UIV (UIV + 1) with polymethylmethacrylate (PMMA)-could also serve as a preventive measure of PJK/PJF in minimally invasive surgery (MIS). Materials and Methods: The study included 29 ASD patients who underwent a combination of minimally invasive lateral lumbar interbody fusion (MIS-LLIF) at L1-2 through L4-5, all-pedicle-screw instrumentation from the lower thoracic spine to the sacrum, S2-alar-iliac fixation, and two-level balloon-assisted PMMA vertebroplasty at the UIV and UIV + 1. Results: With a minimum 3-year follow-up, non-PJK/PJF group accounted for fifteen patients (52%), PJK for eight patients (28%), and PJF requiring surgical revision for six patients (21%). We had a total of seven patients with proximal junctional fracture, even though no patients showed implant/bone interface failure with screw pullout, probably through the effect of PMMA. In contrast to the PJK cohort, six PJF patients all had varying degrees of neurologic deficits from modified Frankel grade C to D3, which recovered to grades D3 and to grade D2 in three patients each, after a revision operation of proximal extension of instrumented fusion with or without neural decompression. None of the possible demographic and radiologic risk factors showed statistical differences between the non-PJK/PJF, PJK, and PJF groups. Conclusions: Compared with the traditional open surgical approach used in the previous studies with a positive result for the prophylactic two-level cement augmentation, the MIS procedures with substantial benefits to patients in terms of less access-related morbidity and less blood loss also provide a greater segmental stability, which, however, may have a negative effect on the development of PJK/PJF.

Strap stabilization for proximal junctional kyphosis prevention in instrumented posterior spinal fusion.

STUDY DESIGN: This is a retrospective, single-institution, cohort study. OBJECTIVES: To evaluate the association of Mersilene tape use and risk of proximal junctional kyphosis (PJK), after surgical correction of adult spinal deformity (ASD) by posterior instrumented fusion (PIF). PJK, following long spinal PIF, is a complication which often requires reoperation. Mersilene tape, strap stabilization of the supra-adjacent level to upper instrumented vertebra (UIV) seems a preventive measure. METHODS: Patients who underwent PIF for ASD with Mersilene tape stabilization (case group) or without (control group) between 2006 and 2016 were analyzed preoperatively to 2-year follow-up. Matching of potential controls to each case was performed. Radiographic sagittal Cobb angle (SCA), lumbar lordosis, pelvic tilt, sacral slope, and pelvic incidence were measured pre- and postoperatively, using a deformity measuring software program. PJK was defined as progression of postoperative junctional SCA at UIV ≥ 10°. RESULTS: Eighty patients were included: 20 cases and 60 controls. The cumulative rate of PJK ≥ 10° at 2-year follow-up was 15% in cases versus 38% of controls (OR = 0.28; P = 0.04) with higher latent period in cases, (20 vs. 7.5 months), P = 0.018. Mersilene tape decreased risk of PJK linked with the impact of the following confounders: age, ≥ 55 years old (OR = 0.19; 0.02 ≥ P ≤ 0.03); number of spinal levels fused 7-15 (OR = 0.13; 0.02 ≥ P ≤ 0.06); thoracic UIV (T12-T1) (OR = 0.13; 0.02 ≥ P ≤ 0.06); BMI ≥ 27 kg/m2 (OR = 0.22; 0.03 ≥ P ≤ 0.08); and osteoporosis (OR = 0.13; 0.02 ≥ P ≤ 0.08). CONCLUSIONS: Mersilene tape at UIV + 1 level decreases the risk of PJK following PIF for ASD. These slides can be retrieved under Electronic Supplementary Material.

Is It Growth or Natural History? Increasing Spinal Deformity After Sanders Stage 7 in Females With AIS.

BACKGROUND: Accurate prognosis and treatment decisions in adolescent idiopathic scoliosis (AIS) demand a reliable radiographic marker of growth cessation. Specifically, Sanders Stage 7 (SS7) is a useful marker of spine growth cessation in females and is proposed as a bracing endpoint. The purpose of this study was to determine the amount of curve progression noted in female individuals with AIS after achieving SS7. We hypothesize that a subset of patients continues to progress at a greater rate than the natural history at SS7. METHODS: This retrospective review included female patients with AIS treated at a single institution from May 2008 to 2018. Patients required a hand radiograph demonstrating SS7 and concurrent spine radiograph measuring <50 degrees, plus 2-year follow-up spine radiograph. Curve types were categorized by the modified Lenke Classification. Risser grade, menarche, height, weight, and bracing data were collected. Progression was defined as an increase of the main curve ≥5 degrees. Comparison between groups was analyzed using independent t tests and χ or Fisher exact tests as appropriate. Binary logistic regressions were used to construct a model predictive of progressing beyond 50 degrees or undergoing surgery. RESULTS: A total of 89 patients met inclusion criteria, average main curve magnitude 33 degrees (SD 9) at SS7 and 38 degrees (SD 11) at 2-year follow-up. Forty-five (51%) patients progressed ≥5 degrees and 17 (19%) progressed at least 10 degrees. Seventy patients had curves <40 degrees at SS7 and 22 (31%) progressed to >40 degrees at 2 years. Eleven (12%) patients progressed to >50 degrees or had surgery at 2-year follow-up. Receiver operating characteristic curve analysis identified a threshold of 39.5 degrees curvature at SS7 associated with progression to >50 degrees or surgery (area under the curve=0.94, P<0.001, sensitivity=100%, specificity=87%). Patients with initial curves >40 degrees did have additional height gained (2.1 cm; SD 1.5), but this was not different than those <40 degrees, P>0.05. In addition, no other variables had statistically significant association with those that progressed (P>0.05). CONCLUSIONS: A curve >40 degrees at SS7 is at high risk for progressing to a curve measuring >50 degrees or requiring surgery. Those with curves below this threshold still have potential to make clinically significant progression after skeletal maturity. Follow-up of patients beyond SS7 is essential for curves measuring >40 degrees. Reaching SS7 with a curve <50 degrees may not be the endpoint for curve progression, even if predictive of the end of spinal growth. LEVEL OF EVIDENCE: Level III-retrospective research study.

Idiopathic Early-onset Scoliosis: Growing Rods Versus Vertically Expandable Prosthetic Titanium Ribs at 5-year Follow-up.

BACKGROUND: Distraction-based techniques allow spinal growth until skeletal maturity while preventing curve progression. METHODS: Two multicenter early-onset scoliosis databases were used to identify patients with idiopathic spine abnormalities treated with traditional growing rods (TGR) or vertically expandable titanium ribs (VEPTR). Patients underwent at least 4 lengthenings and had at least 5-year follow-up. Significance was set at P<0.05. RESULTS: In total, 50 patients treated with TGR and 22 treated with VEPTR were included. Mean (±SD) age at surgery was 5.5 (±2.0) years for the TGR group versus 4.3 (±1.9) years for the VEPTR group (P=0.044); other demographic parameters were similar. VEPTR patients had more procedures (mean 15±4.2) than TGR patients (mean 10±4.0) (P=0.001). Unilateral constructs were present in 18% (4 of 22) of VEPTR and 16% (8 of 50) of TGR patients. Bilateral constructs spanned a mean 2.1 additional surgical levels and exposed patients to 1.6 fewer procedures than unilateral constructs. Curve correction was similar between bilateral and unilateral constructs. TGR patients experienced greater curve correction (50%) than VEPTR patients (27%) (P<0.001) and achieved a greater percentage of thoracic height gain (24%) than VEPTR patients (12%) (P=0.024). At latest follow-up, TGR patients had better maintenance of curve correction, less kyphosis, and 15% greater absolute gain in thoracic height versus VEPTR patients. TGR patients had a lower rate of wound complications (14%) than VEPTR patients (41%) (P=0.011). CONCLUSIONS: In patients with idiopathic early-onset scoliosis, TGRs produced greater initial curve correction, greater thoracic height gains, less kyphosis, and lower incidence of wound complications compared with VEPTR. LEVEL OF EVIDENCE: Level III.

Cervical alignment after single-level anterior cervical corpectomy and fusion using autologous bone graft without spinal instrumentation for cervical pyogenic spondylitis.

BACKGROUND: Subsidence in anterior cervical corpectomy and fusion (ACCF) for cervical degenerative disease (CDD) are constantly observed during the postoperative course. Although kyphotic change of cervical alignment occurred frequently in cervical pyogenic spondylitis (CPS) postoperatively, studies on the postoperative change in segmental angle for CPS are limited. This study aimed to analyze cervical alignment after single-level ACCF using autologous bone graft without spinal instrumentation for CPS compared with that for CDD. METHODS: Six patients underwent single-level ACCF using autologous bone graft without spinal instrumentation for CPS. The control group included 18 age-matched patients who underwent single-level ACCF using autologous bone graft for CDD without spinal instrumentation for the same duration. Cervical and lateral plain radiographs and computed tomography scans were taken. The Frankel classification was used to assess the neurological status preoperatively, postoperatively, and at 2-year follow-up for CPS. RESULTS: At 2-year follow-up, the average segmental angle at the fusion level was - 12.2° ± 6.9° for CPS and - 5.2° ± 7.6° for CDD (p = 0.04). Changes in segmental angle at the fusion level were - 7.2 ± 9.0° for CPS and - 1.1° ± 7.1° for CDD (p = 0.02). At 2-year follow-up, the average anterior segmental fusion height was 23.4 ± 1.7 mm for CPS and 29.1 ± 5.1 mm for CDD (p < 0.001). At 2-year follow-up, bone fusion in the CPS group was classified as grade 5 (complete fusion) in 4 patients (66.7%) and grade 4 (probable fusion) in 2 (33.3%). In the CDD group, it was grade 5 in 13 patients (72.2%) and grade 4 in 5 patients (27.8%). Overall, both groups achieved 100% bone fusion rate. The Frankel classification in all CPS cases improved or leveled off. CONCLUSION: Progression of segmental kyphosis angle and subsidence of graft bone were observed postoperatively on all CPS cases. However, the neurological recovery and bone union were satisfactory.

Spinal Instrumentation in Growing Children Retards the Natural Development of Pelvic Incidence.

BACKGROUND: Pelvic incidence increases gradually throughout growth until skeletal maturity. Growing rod instrumentation has been suggested to have a stabilizing effect on the development of the normal sagittal spinal alignment. The purpose of this study is to determine the effect of fixed sagittal plane caused by dual growing rod instrumentation on the natural progression of sagittal spinopelvic parameters in children with idiopathic or idiopathic-like early onset scoliosis. METHODS: Hospital records of children with growing rod instrumentation from 4 separate institutions were reviewed retrospectively. Inclusion criteria were idiopathic or idiopathic-like early onset scoliosis, treatment with dual growing rods with lower instrumented vertebra L4 or upper and more than 2 years of follow-up. Instrumentation levels, magnitudes of major curve, thoracic kyphosis (T2-T12), lumbar lordosis (L1-S1) and pelvic incidence were recorded from preoperative and postoperative standing whole-spine radiographs. Estimated pelvic incidence was also calculated for each patient as if their spines had not been instrumented using the previous normative data. RESULTS: A total of 37 patients satisfied the inclusion criteria. Average age at initial surgery was 7.4±1.8 years (range, 4 to 12 y). Mean follow-up time was 71±26 months (range, 27 to 120 mo). Mean preoperative Cobb angle of 59±13.5 (range, 30 to 86) degrees was reduced to 35.1±17.5 (range, 11 to 78) degrees at the last follow-up. Mean preoperative T2-T12 kyphosis angle was 46.2±14.9 degrees (range, 22 to 84 degrees). At the latest follow-up, it was 44.8±16.2 degrees (range, 11 to 84 degrees) (P=0.93). Mean L1-S1 lordosis angle was 50.5±10.7 degrees (range, 30 to 72 degrees) preoperatively. At the latest follow-up, mean L1-S1 lordosis angle was 48.8±12.7 degrees (range, 26 to 74 degrees) (P=0.29). Mean preoperative pelvic incidence was 45.7±7.9 degrees (range, 30 to 68 degrees). At the latest follow-up, it was 46.7±8.4 degrees (range, 34 to 72 degrees) (P=0.303). The estimated average pelvic incidence was 49.5 degrees (P=0.012). CONCLUSIONS: Previously reported developmental changes of the sagittal spinal parameters were not observed in children who underwent posterior spinal instrumentation. Our findings suggest that spinal instrumentation impedes the natural development of the sagittal spinal profile. LEVEL OF EVIDENCE: Level IV-this is a retrospective case-series.

Successful Management of Gorham-Stout Disease in the Cervical Spine by Combined Conservative and Surgical Treatments: A Case Report.

Gorham-Stout disease (GSD) is a rare condition characterized by intraosseous proliferation of endothelial-lined vessels and progressive osteolysis. The precise etiology and pathophysiology of the disease remain poorly understood. Current therapeutic options for GSD include chemotherapy, radiotherapy, and surgical resection, but the surgical treatment of GSD is difficult, especially in the spinal lesion. The indication of wide-margined resection was limited because of anatomical features. Herein, we report a case of GSD of the cervical spine in which the lesions were successfully stabilized with combined conservative and surgical treatments. A 15-year-old male patient was admitted because of severe neck pain. The patient presented no neurological deficiency. However, the radiological findings revealed osteolytic lesions on the laminae and vertebrae between C1 to C5. An open biopsy confirmed an irregular, thin-walled vessel formation in the bone trabeculae, which was diagnosed as GSD. Conservative treatment was initiated with chemotherapy and radiotherapy. After one and a half year, the osteolytic condition had regressed. Spinal fusion surgery was then performed from C2 to C5 to prevent for progression of the cervical kyphotic changes, and spinal fusion was confirmed 7 months after the surgery. The patient showed no recurrence of GSD in the 5-year follow-up period after surgery. We were able to provide successful treatment by giving priority to the combined conservative treatments. If a patient has no severe deformity or progressive neurologic deficits, it might be better to prioritize conservative treatments and to perform the surgery after the osteolytic changes have stopped.

Spinal disease in myeloma: cohort analysis at a specialist spinal surgery centre indicates benefit of early surgical augmentation or bracing.

BACKGROUND: Multiple myeloma osteolytic disease affecting the spine results in vertebral compression fractures. These are painful, result in kyphosis, and impact respiratory function and quality of life. We explore the impact of time to presentation on the efficacy of spinal treatment modalities. METHODS: We retrospectively reviewed 183 patients with spinal myeloma presenting to our service over a 2 year period. RESULTS: Median time from multiple myeloma diagnosis to presentation at our centre was 195 days. Eighty-four patients (45.9 %) were treated with balloon kyphoplasty and the remainder with a thoracolumbar-sacral orthosis as per our published protocol. Patients presenting earlier than 195 days from diagnosis had significant improvements in patient reported outcome measures: EuroQol 5-Dimensions (p < 0.001), Oswestry Disability Index (p < 0.001), and Visual Analogue Pain Score (p < 0.001) at follow-up, regardless of treatment. Patients presenting after 195 days, however, only experienced benefit following balloon kyphoplasty, with no significant benefit from non-operative management. CONCLUSION: Vertebral augmentation and thoracolumbar bracing improve patient reported outcome scores in patients with spinal myeloma. However, delay in treatment negatively impacts clinical outcome, particularly if managed non-operatively. It is important to screen and treat patients with MM and back pain early to prevent deformity and improve quality of life.

Laminar closure rates in patients with cervical myelopathies treated with either open-door laminoplasty with reattachment of spinous processes and extensor musculature or Hirabayashi open-door laminoplasty: a case-control study.

PURPOSE: The presence of preoperative kyphosis has been identified as a risk factor for laminar closure (LC). We have been performing modified open-door laminoplasty with reattachment of the spinous processes and extensor musculature for patients with reduced cervical lordosis because this procedure can prevent progression of cervical kyphosis. This procedure may also prevent LC. The purpose of this study was to evaluate the rate of LC after the modified open-door laminoplasty. METHODS: A total of 104 patients who underwent open-door laminoplasty were retrospectively reviewed. Of these patients, 18 underwent modified open-door laminoplasty (group M), whereas the other 86 underwent Hirabayashi open-door laminoplasty (group H). Group H was divided into two classes according to the preoperative cervical lordosis angle (group H1 ≤ 10° vs. group H2 ≥ 11°). All 18 patients in group M had a preoperative lordosis angle ≤10°. The outcomes were assessed using the rate of LC, the cross-sectional area (CSA) of the erector muscle on magnetic resonance imaging, and the Japanese Orthopaedic Association score (JOA score). RESULTS: The rate of laminar closure was significantly lower in group M (39 %) than in group H1 (76 %) (P < 0.01). The CSAs tended to be larger in the muscle preservation side of group M than in the other groups. There was no significant difference in the JOA score among the three groups. CONCLUSIONS: Although patients with decreased cervical lordosis have a higher risk of LC, the results suggested that modified open-door laminoplasty could reduce the rate of LC compared with Hirabayashi open-door laminoplasty.

THE INFLUENCE OF POSTERIOR APPROACH CERVICAL INTRASPINAL TUMOR RESECTION ON THE STABILITY OF CERVICAL VERTEBRA.

This paper discusses the influence of posterior approach cervical intraspinal tumor resection on the stability of cervical vertebra. A total of 32 patients with cervical intraspinal tumor were included and divided into a group undergoing posterior approach bilateral vertebral lamina resection (group A) (n=16) and a group undergoing posterior approach semi-laminectomy (group B) (n=16). It was found, through follow-up visits, that the incidence rate of cervical instability of the patients was 25% and the incidence rate of cervical curvature deterioration of the patients was 37.5% in group A, whereas the two incidence rates of group B were 6.25% and 12.5% respectively; the incidence rates of cervical curvature deterioration and instability were significantly increased compared to group B (P< 0.05). It is concluded that, both regular posterior approach vertebral lamina resection and semi-laminectomy influence the biomechanical change of cervical vertebra, but the influence of the latter is less. Also, it is found that, applying titanium connectors and titanium nails for rigid internal fixation maintains the completeness and stability of the structure of the cervical vertebra.

Prevention of proximal junctional kyphosis after posterior surgery of Scheuermann kyphosis: an operative technique.

STUDY DESIGN: A prospective randomized study. OBJECTIVE: To introduce an operative technique that prevents proximal junctional kyphosis (PJK) in Scheuermann disease after a segmental posterior spinal instrumentation and fusion. SUMMARY OF BACKGROUND DATA: PJK is the progression of kyphotic deformity at the proximal end of a construct >10 degrees, and it can be seen up to 30% after posterior Scheuermann kyphosis surgery. After posterior fusion the biomechanics of the spine changes and the loss of motion at the fused levels is compensated by increased motion at other unfused segments. As a result significant amount of additional force is placed on the proximal junction. With our operative technique, we aimed to have a smooth passage from rigid to mobile segments and to decrease the stress on proximal junction during cantilever reduction to prevent PJK. METHODS: A total of 60 consecutive patients (mean age: 18.27±3.19, male/female: 28/32) who were surgically treated for Scheuermann kyphosis in our institution were recruited into this study and were prospectively evaluated. Patients were divided into 2 groups according to upper-most screw fixation technique. In group 1, a standard screw insertion technique was used (ST group). The technique was modified in group 2 (MT group), leaving 2 threads out of the posterior cortex. There were 29 patients in group 1 (ST) and 31 patients in group 2 (MT). Patients had an average follow-up time of 24.2 months (range, 19-48 mo). Evaluated radiographic parameters were preoperative and postoperative kyphosis angle, and proximal junctional angle (PJA) at last visit. PJA was defined as the angle between the caudal endplate of the upper instrumented vertebra and the cephalad endplate of 2 suprajacent vertebrae above the upper instrumented vertebra. PJA exceeding 10 degrees was accepted as PJK. Quality of life measurement was assessed preoperatively and postoperatively with SF-36 questionnaire. RESULTS: Correction amounts in ST group and MT group were 46.8% and 43.7%, respectively, which was statistically insignificant. The mean PJA was 8.08±2.96 degrees and 4.44±1.55 degrees in ST and MT groups, respectively, which demonstrated a statistically significant difference (P=0.001). Five patients in ST group had a PJA exceeding 10 degrees (PJK), whereas PJK was not seen in MT group (P=0.022). The improvement in physical component summary of SF-36 was significantly better in MT group; however, mental component summary was similar in both groups. CONCLUSIONS: This study introduces a new technique that may have an effect in preventing PJK. Our results seem to be satisfactory, but additional studies with more patients and longer follow-up times are needed to further delineate the feasibility of this technique.

Suppression of mTORC1 activation in acid-α-glucosidase-deficient cells and mice is ameliorated by leucine supplementation.

Pompe disease is due to a deficiency in acid-α-glucosidase (GAA) and results in debilitating skeletal muscle wasting, characterized by the accumulation of glycogen and autophagic vesicles. Given the role of lysosomes as a platform for mTORC1 activation, we examined mTORC1 activity in models of Pompe disease. GAA-knockdown C2C12 myoblasts and GAA-deficient human skin fibroblasts of infantile Pompe patients were found to have decreased mTORC1 activation. Treatment with the cell-permeable leucine analog L-leucyl-L-leucine methyl ester restored mTORC1 activation. In vivo, Pompe mice also displayed reduced basal and leucine-stimulated mTORC1 activation in skeletal muscle, whereas treatment with a combination of insulin and leucine normalized mTORC1 activation. Chronic leucine feeding restored basal and leucine-stimulated mTORC1 activation, while partially protecting Pompe mice from developing kyphosis and the decline in muscle mass. Leucine-treated Pompe mice showed increased spontaneous activity and running capacity, with reduced muscle protein breakdown and glycogen accumulation. Together, these data demonstrate that GAA deficiency results in reduced mTORC1 activation that is partly responsible for the skeletal muscle wasting phenotype. Moreover, mTORC1 stimulation by dietary leucine supplementation prevented some of the detrimental skeletal muscle dysfunction that occurs in the Pompe disease mouse model.

Preventive effects of conservative treatment with short-term teriparatide on the progression of vertebral body collapse after osteoporotic vertebral compression fracture.

UNLABELLED: The progression of fractured vertebral collapse is not rare after a conservative treatment of vertebral compression fracture (VCF). Teriparatide has been shown to directly stimulate bone formation and improve bone density, but there is a lack of evidence regarding its use in fracture management. Conservative treatment with short-term teriparatide is effective for decreasing the progression of fractured vertebral body collapse. INTRODUCTION: Few studies have reported on the prevention of collapsed vertebral body progression after osteoporotic VCF. Teriparatide rapidly enhances bone formation and increases bone strength. This study evaluated preventive effects of short-term teriparatide on the progression of vertebral body collapse after osteoporotic VCF. METHODS: Radiographs of 68 women with single-level osteoporotic VCF at thoracolumbar junction (T11-L2) were reviewed. Among them, 32 patients were treated conservatively with teriparatide (minimum 3 months) (group I), and 36 were treated with antiresorptive (group II). We measured kyphosis and wedge angle of the fractured vertebral body, and ratios of anterior, middle, and posterior heights of the collapsed body to posterior height of a normal upper vertebra were determined. The degree of collapse progression was compared between two groups. RESULTS: The progression of fractured vertebral body collapse was shown in both groups, but the degree of progression was significantly lower in group I than in group II. At the last follow-up, mean increments of kyphosis and wedge angle were significantly lower in group I (4.0° ± 4.2° and 3.6° ± 3.6°) than in group II (6.8° ± 4.1° and 5.8° ± 3.5°) (p = 0.032 and p = 0.037). Decrement percentages of anterior and middle border height were significantly lower in group I (9.6 ± 10.3 and 7.4 ± 7.5 %) than in group II (18.1 ± 9.7 and 13.8 ± 12.2 %) (p = 0.001 and p = 0.025), but not in posterior height (p = 0.086). CONCLUSIONS: In female patients with single-level osteoporotic VCF at the thoracolumbar junction, short-term teriparatide treatment did not prevent but did decrease the progression of fractured vertebral body collapse.

Pregnancy-associated osteoporosis with eight fractures in the vertebral column treated with kyphoplasty and bracing: a case report.

Pregnancy-associated osteoporosis is a rare condition, which imposes multiple symptoms in the musculoskeletal system. Common complaints announced by patients are severe pain in the lower back, hips and the joints of the lower extremities with a reduced and less mobility status in general. Most of the patients' problems occur in the last trimester of pregnancy or postpartum and are often not diagnosed as side effects of osteoporosis but as problems associated with pregnancy. Although vertebral fractures are rare complications of pregnancy-associated osteoporosis, they should be always considered in women presenting with an acute pain syndrome in peripregnancy period. This case presents a 40-year-old primagravid woman who developed pain in hips and severe pain in the lower back causing an immobilization diagnosed with a pregnancy-associated osteoporosis with eight compression fractures in the thoracic and lumbar spine. Because of sagittal imbalance of the spine, she was treated with kyphoplasty at the four lumbar fractures and with bracing for the upper, thoracic ones, additional to the conservative anti-osteoporotic therapy. The authors discuss pregnancy-associated osteoporosis and its clinical presentation, as well as the indications of kyphoplasty, spinal alignment and the risk of single conservative treatment.

Gravity Line-Hip Axis Offset as a Guide for Global Alignment to Prevent Recurrent Proximal Junctional Kyphosis/Failure.

BACKGROUND AND OBJECTIVES: Proximal junctional kyphosis/failure (PJK/F) is a potentially serious complication after adult spinal deformity (ASD) corrective surgery. Recurrent PJK/F is especially troublesome, necessitating fusion extension and occasionally resulting in irreversible neurological deficits. The gravity line (GL) offers valuable insights into global sagittal balance. This study aims to examine the postoperative GL-hip axis (GL-HA) offset as a critical risk factor for recurrent PJK/F. METHODS: We retrospectively reviewed patients with ASD who had undergone revision surgery for initial PJK/F at a single academic center. Patients were categorized into 2 groups: nonrecurrent PJK/F group and recurrent PJK/F group. Demographics, surgical characteristics, preoperative and postoperative parameters of spinopelvic and global alignment, and the Scoliosis Research Society-22 scores were assessed. We examined these measures for differences and correlations with recurrent PJK/F. RESULTS: Our study included 32 patients without recurrent PJK/F and 28 patients with recurrent PJK/F. No significant differences were observed in baseline demographics, operative characteristics, or Scoliosis Research Society-22 scores before and after surgery. Importantly, using a cutoff of -52.6 mm from logistic regression, there were considerable differences and correlations with recurrent PJK/F in the postoperative GL-HA offset, leading to an odds ratio of 7.0 (95% CI: 1.94-25.25, P = .003). CONCLUSION: Postoperative GL-HA offset serves as a considerable risk factor for recurrent PJK/F in patients with ASD who have undergone revision surgery. Overcorrection, with GL-HA offset less than -5 cm, is associated with recurrent PJK/F. The instrumented spine tends to align the GL near the HA, even at the cost of proximal junction.

The potential of proximal junctional kyphosis prevention using a novel tether pedicle screw construct: an in silico study comparing the influence of standard and dynamic techniques on adjacent-level range of motion and load pattern.

OBJECTIVE: A tether pedicle screw (TPS) enables individual stepless pretensioning and is placed at one or two levels above the upper instrumented vertebra (UIV+1 and UIV+2, respectively). This study aimed to evaluate a novel customized TPS for the prevention of proximal junctional kyphosis (PJK) and to investigate the potential to generate a smoother force transition from cranial to long fusion during trunk flexion, instead of an abrupt change at the UIV, following adult spinal deformity surgery. METHODS: A finite element model was designed based on an adult patient with spinal deformity instrumented from T10 to S1. Five different sagittal balance types and implant configurations were tested. The proximal range of motion (ROM) and intervertebral stress were examined, with a special focus on their respective discontinuities. RESULTS: Tension shielding at UIV/UIV+1 by the TPS was consistent irrespective of sagittal profiles. The use of TPSs at UIV+1 and UIV+2 increased the efficacy in reducing spinal ROM discontinuity at UIV/UIV+1, as compared with the use of TPSs at UIV+1 only. Through the use of two pairs of TPSs cranial to the UIV, the optimal tension configuration could be defined to avoid a reduction effect at UIV+1. Neither the addition of transition rods to the TPSs nor the use of transition rods in combination with standard pedicle screws improved the junctional mechanics when compared with TPSs at UIV+1/UIV+2. CONCLUSIONS: A smoother motion discontinuity at the UIV can be achieved via implementation of a TPS strategy. This new technology shows favorable in silico mechanics for reducing the risk of PJK.

Tension Parameters of Junctional Tethers in Proximal Junction Kyphosis: A Cadaveric Biomechanical Study.

OBJECTIVE: Proximal junctional failure following surgical correction for adult spinal deformity significantly impacts quality of life and increases the economic burden of treating underlying spinal deformity. The objective of this cadaver study was to determine optimal tension parameters in junctional tethers for proximal junctional kyphosis prevention. METHODS: Cadaveric specimens were used to establish the optimal tension range in polyethylene tethering devices, such as the VersaTie (NuVasive) used in this study. Three specimens were instrumented to test tether tensions of 0, 75, and 150 Newtons (N) at L1-L2, T9-T10, and T3-T4. An optical tracking system was used to measure when specimens reached proximal junctional kyphosis, experienced instrumentation or tissue failure, or reached a cap of 2500 cycles. Radiographs were obtained before and after testing. RESULTS: At all levels, use of a tether at tension forces of 75 N and 150 N elicited a protective effect. The only level in which a higher tension on the tether resulted in more protection was at T3-T4. When averaged, the use of a tether at tension forces of 75 N and 150 N showed 1000 cycles of protection at L1-L2, 2000 cycles at T9-T10, and 1426 cycles at T3-T4. Radiographic analysis corroborated these findings. CONCLUSIONS: The use of a tether in a cadaveric model prevents the development of proximal junctional kyphosis across all tested levels and an increased tension force of 150 N is protective at the proximal thoracic spine. These data can be used to develop further models for a tether system that reproducibly applies a fixed tension force above the thoracolumbar rod construct.

Does Minimally Invasive Hemilaminectomy for Intradural Extramedullary Tumor Resection Prevent Postlaminectomy Kyphosis or Lordosis Loss?

BACKGROUND: Minimally invasive hemilaminectomy is a safe and effective alternative to open laminectomy for treating intradural extramedullary tumors. There are no reports of postoperative kyphosis after this approach. This study aims to determine whether performing minimally invasive spine surgery hemilaminectomy for intradural extramedullary tumors can prevent the development of postlaminectomy kyphosis (PLK) or lordosis loss. MATERIAL AND METHODS: Sixty-five patients with spinal intradural extramedullary tumors who underwent minimally invasive hemilaminectomy surgery and complete pre and postoperative radiologic imaging were included. The effect of the surgical approach on the spinal sagittal axis was assessed by comparing pre- versus postoperative segmental and local Cobb angles at different spinal levels, considering anatomical localization (cervical, thoracic, lumbar, and transition segments) and functional features (mobile, semi-rigid, and transition segments), as well as the extent of the surgical approach (1, 2, or 3 levels) and follow-up. RESULTS: None of the patients had an increase in thoracic kyphosis nor a loss of cervical or lumbar lordosis greater than or equal to 10° after undergoing the minimally invasive spine surgery hemilaminectomy approach. More than 5° of increase in kyphosis was detected on 7.4% and 11.1%, for the segmental and the local angles, respectively; meanwhile, for patients with loss of lordosis, this deviation was detected in 5.3%, for both angles. The occurrence of PLK was more common than that of lordosis loss, but mainly manifested in postoperative angle impairment of less than 5°. No significant differences were evidenced, considering the approach length. CONCLUSIONS: Hemilaminectomy represents a promising approach for preventing PLK and postlaminectomy lordosis loss following intradural extramedullary tumor resection.

Using Proximal Hooks as a Soft-Landing Strategy to Prevent Proximal Junctional Kyphosis in the Surgical Treatment of Scheuermann's Kyphosis.

AIM: To evaluate the occurrence of proximal junctional kyphosis (PJK) as well as both the clinical and radiologic outcomes of patients who underwent surgery for Scheuermann?s Kyphosis (SK) using either exclusively pedicle screws or a combination of proximal hooks and pedicle screws constructs. MATERIAL AND METHODS: Surgically treated 37 patients with the diagnosis of SK were evaluated retrospectively. The patients were divided into two groups based on the type of instrumentation employed. The first group contained 22 patients with only pedicle screws (PP) while the second group consisted of 15 patients with mixed constructs that were proximal hooks and pedicle screws (HP) at the rest of the levels. The clinical and radiological data were compared in patients who were followed up for a minimum of 2 years. RESULTS: The average duration of follow-up for the PP group was approximately 94.7 ± 53.1 months, whereas the HP group had an average follow-up period of around 103 ± 64.4 months. After conducting the analyses, no statistically significant findings were identified in the measurements taken for the SRS-22 scores in preoperative, postoperative, and the most recent follow-up radiographs (p > 0.05). It is worth noting that among patients who exclusively utilized pedicle screws, both the proximal (p=0.045) and distal (p=0.030) junctional kyphosis angles experienced more pronounced increases compared to hybrid structures. CONCLUSION: While no notable distinction was observed between the two groups, patients with pedicle screws fixation had a higher PJK angle. Conversely, the use of hooks at the upper end seems to be a preventive measure against the development of PJK.