Instrumented Posterior Spinal Fusion Research Articles

Ponte osteotomies for treatment of spinal deformities: they are not all made equal.

To compare surgical outcomes of Ponte's osteotomies for treatment of adolescent idiopathic scoliosis (AIS), Scheuermann's kyphosis (SK), and adult scoliosis (AdS). We conducted a retrospective review of patients with AIS, SK, and AdIS who underwent posterior spinal instrumented fusion (PSIF) at our Institution from January 2019 to December 2022. Demographics, imaging, and intraoperative data (including number of osteotomies performed, blood losses, surgical timing, and complications) were extracted from patient charts. A total of 80 patients (62 AIS, 7 SK, and 11 AdS) were enrolled in the study. All patients were treated with a PSIF and a total of 506 Ponte osteotomies were performed (5.8 ± 4.1, 9.3 ± 2.4, and 7.5 ± 2.5 average osteotomies per patient in the AIS, SK, and AdS group, respectively; p = 0.045). Average time per osteotomy was 6.3 ± 1.5min in the AIS group, and 5.8 ± 2.1 and 8.7 ± 4.0 in the SK and AdS group, respectively (p = 0.002). Blood loss was significantly smaller in the SK group (8.6 ± 9.6ml per osteotomy) compared to AIS group (34.9 ± 23.7ml) and AdS group (34.9 ± 32.7ml) (p = 0.001). A total of 4 complications were observed in the AIS group (1.1%) and 2 complications in the AdS group (2.4%), but this was not statistically significant. Our study shows that Ponte's osteotomies are safe and effective in surgical treatment of AIS, SK, and AdS. Blood loss and execution time per osteotomy are significantly smaller in the SK group compared to AIS and AdS. No significant differences were noted in terms of complications between the three groups.

412 Incisional Negative Pressure Wound Therapy Following Posterior Instrumented Spinal Fusion: A Single Surgeon’s Experience and Cost-Benefit Analysis

INTRODUCTION: Surgical site infections (SSIs) following spine surgery are associated with significant morbidity and resource utilization. METHODS: We retrospectively reviewed all patients who received posterior instrumented spinal fusion by the senior author between July 2017 and December 2019 at a Level I trauma center. Statistical analysis was performed using Chi-square and Student’s t-tests. RESULTS: A total of 85 patients with standard surgical dressings and 144 patients with iNPWT were included for analysis. Patients in the iNPWT group were significantly older (61.8 vs. 58.5 years, p = 0.042) and more likely to be diabetic (36.8% vs. 23.5%, p = 0.037). Surgeries in the iNPWT group were associated with significantly greater blood loss (1298 mL vs. 998 mL, p = 0.036) and involved more instrumented levels (6.6 vs. 4.9, p < 0.0001). Prophylactic iNPWT use was associated with significantly lower rates of wound dehiscence (21.5% vs. 34.1%, p = 0.036) and SSI requiring operative treatment (8.3% vs. 21.2%, p = 0.005). The incidence of wound dehiscence requiring operative wound revision was lower with iNPWT (14.6% vs. 24.7%, p = 0.056), though it did not reach statistical significance. Number needed to treat (NNT) with iNPWT to prevent one SSI was 7.79. The cost of preventing one operative SSI was $5,096. Cost-benefit analysis demonstrated a potential mean savings of $26,149 per operative SSI and $326,862 per 100 patients undergoing posterior instrumented spinal fusion with iNPWT. CONCLUSIONS: Prophylactic iNPWT use significantly reduced rates of wound dehiscence, SSI requiring operative treatment, and affords a potential SSI-related cost savings of $326,862 per 100 patients treated.

Impact of a quality improvement initiative and monthly multidisciplinary meetings on outcomes after posterior spinal fusion for adolescent idiopathic scoliosis.

Several studies have demonstrated the benefits of enhanced recovery after surgery (ERAS) protocols for patients with adolescent idiopathic scoliosis (AIS) undergoing posterior spinal instrumented fusion (PSIF). However, there are relatively few studies investigating the effect of regular multidisciplinary team meetings on level selection, surgical performance parameters, and patient outcomes after PSIF for AIS. The aim of this study was to assess changes in intra- and postoperative outcomes following multidisciplinary team meeting implementation for patients undergoing PSIF for AIS. The medical records of 96 adolescents (10 to 18years old) diagnosed with AIS and undergoing PSIF at a major academic institution from 2017 to 2022 were retrospectively reviewed. A quality improvement (QI) initiative was implemented in February 2020, including institution of monthly multidisciplinary conferences focusing on preoperative indications, level selection, postoperative review of surgical performance parameters for previous cases, and discussion and optimization of postoperative ambulation and pain control protocols. Patients were placed into "Pre-QI" (treated pre-February 2020) and "Post-QI" (treated post-February 2020) cohorts. Patient demographics, comorbidities, deformity characteristics, intraoperative variables, ambulation status, postoperative complications, length of stay (LOS), and unplanned readmission rates were assessed. Of the 96 study patients, 44 (45.8%) were in the Pre-QI cohort, and 52 (54.2%) were in the Post-QI cohort. Mean major curve was not significantly different between the two cohorts (Pre-QI: 58.0 ± 7.3° vs Post-QI: 57.9 ± 14.5°, p = 0.169). The Pre-QI cohort had a greater mean minor curve degree (Pre-QI: 42.7 ± 11.8° vs Post-QI: 36.8 ± 12.4, p = 0.008). The Pre-QI cohort had significantly greater mean spinal levels fused (Pre-QI: 11.7 ± 1.7 vs Post-QI: 10.4 ± 2.6, p = 0.009), significantly greater mean estimated blood loss (Pre-QI: 1063.6 ± 631.5ml vs. Post-QI: 415.8 ± 189.9ml, p < 0.001), significantly greater mean operative time normalized to levels fused (Pre-QI: 0.6 ± 0.1h/level fused vs Post-QI: 0.4 ± 0.1h/level fused, p < 0.001), and a significantly greater proportion of patients with intraoperative drain placement (Pre-QI: 93.2% vs Post-QI: 5.8%, p < 0.001). The Post-QI cohort had significantly shorter time to postoperative ambulation (Pre-QI: 2.1 ± 0.9days vs Post-QI: 1.3 ± 0.5days, p < 0.001). A significantly greater proportion of patients in the Pre-QI cohort developed any postoperative complication (Pre-QI: 72.7% vs Post-QI: 34.6%, p < 0.001), and mean LOS was significantly greater among Pre-QI patients (Pre-QI: 4.5 ± 1.1days vs Post-QI: 3.2 ± 0.8days, p < 0.001). Discharge disposition (p = 0.758) and 30-day unplanned readmissions (p = 0.207) were similar between the cohorts. Our findings suggest that monthly multidisciplinary pediatric spine team meetings may improve patient care. Further studies exploring the incorporation of QI implementation with frequent multidisciplinary team meetings into existing ERAS protocols are merited.

A Sodium Oxychlorosene-Based Infection Prevention Protocol Safely Decreases Postoperative Wound Infections in Adult Spinal Deformity Surgery.

This study sought to determine the efficacy of a complex multi-institutional sodium oxychlorosene-based infection protocol for decreasing the rate of surgical site infection after instrumented spinal surgery for adult spinal deformity (ASD). Infection prevention protocols have not been previously studied in ASD patients. A retrospective analysis was performed of patients who underwent posterior instrumented spinal fusion of the thoracic or lumbar spine for deformity correction between January 1, 2011, and May 31, 2019. The efficacy of a multi-modal infection prevention protocol was examined. The infection prevention bundle consisted of methicillin-resistant Staphylococcus aureus testing, chlorhexidine gluconate bathing preoperatively, sodium oxychlorosene rinse, vancomycin powder placement, and surgical drain placement at the time of surgery. About 254 patients fit the inclusion criteria. Among these patients, nine (3.5%) experienced post-surgical deep-wound infection. Demographics and surgical characteristics amongst infected and non-infected cohorts were similar, although diabetes trended towards being more prevalent in patients who developed a postoperative wound infection (p=0.07). Among 222 patients (87.4%) who achieved a minimum of two years of follow-ups, 184 patients (82.9%) experienced successful fusion, comparing favorably with pseudarthrosis rates in the ASD literature. Rates of pseudarthrosis and proximal junction kyphosis were similar amongst infected and non-infected patients. An intraoperative comprehensive sodium oxychlorosene-based infection prevention protocol helped to provide a low rateof infection after major deformity correction without negatively impacting other postoperative procedure-related metrics.

Accelerated Recovery Protocol Following Posterior Spinal Instrumented Fusion for Adolescent Idiopathic Scoliosis Leading to Early Hospital Discharge: A Quality Improvement Project

Accelerated Recovery Protocol Following Posterior Spinal Instrumented Fusion for Adolescent Idiopathic Scoliosis Leading to Early Hospital Discharge: A Quality Improvement Project

Combined Anterior Thoracic Vertebral Body Tethering and Posterior Lumbar Tethering Results in Quicker Return to Sport and Activity Compared to Posterior Spinal Instrumented Fusion in Patients with Adolescent Idiopathic Scoliosis.

Retrospective comparative study. To compare patient-reported physical activity between anterior thoracic vertebral body tethering and posterior lumbar spine tethering (ATVBT/PLST) and posterior spinal instrumentation and fusion (PSIF) with minimum 2year follow-up. Consecutive skeletally immature patients with idiopathic scoliosis and a thoracic and lumbar curve magnitude ≥40° who underwent either ATVBT/PLST or PSIF from 2015-2019 were included. The primary outcome was rate of returning to sport. Secondary outcomes included ability to bend and satisfaction with sport performance as well as weeks until return to sport, school, physical education (PE) classes, and running. Ten patients underwent ATVBT/PLST and 12 underwent PSIF. ATVBT/PLST patients reported significantly faster return to sport (13.5weeks vs 27.9weeks, P = .04), running (13.3weeks vs 28.8weeks, P = .02), and PE class (12.6weeks vs 26.2weeks, P = .04) compared to PSIF patients. ATVBT/PLST patients reported that they had to give up activities due to their ability to bend at lower rates than PSIF patients while reporting "no changes" in their ability to bend after surgery at higher rates than PSIF patients (0% vs 4% giving up activities and 70% vs 0% reporting no changes in bending ability for ATVBT/PLST and PSIF, respectively, P = .01). Compared to PSIF patients, ATVBT/PLST patients experienced less main thoracic and thoracolumbar/lumbar curve correction at most recent follow-up (thoracic: 41 ± 19% vs 69 ± 18%, P = .001; thoracolumbar/lumbar: 59 ± 25% vs 78 ± 15%, P = .02). No significant differences in the number of revision surgeries were observed between ATVBT/PLST and PSIF patients (4 (40%) and 1 (8%) for ATVBT/PLST and PSIF, respectively, P = .221). ATVBT/PLST patients reported significantly faster rates of returning to sport, running, and PE. In addition, ATVBT/PLST patients were less likely to have to give up activities due to bending ability after surgery and reported no changes in their ability to bend after surgery more frequently than PSIF patients. However, the overall rate of return to the same or higher level of sport participation was high amongst both groups, with no significant difference observed between ATVBT/PLST and PSIF patients.

Effects of Preoperative Use of Povidone-Iodine–Impregnated Dressing on Postoperative Rate of Surgical Site Infection in Patients Undergoing Posterolateral Lumbar Spinal Fusion Surgery: A Randomized, Nonblinded, Active-Controlled Trial

BACKGROUND AND OBJECTIVES: No study has evaluated the efficacy of using preoperative antiseptic dressings in reducing the rate of surgical site infection (SSI) in spine surgery thus far. To investigate the efficacy of the use of preoperative povidone-iodine–impregnated antiseptic dressings in patients undergoing instrumented posterolateral lumbar spinal fusion. METHODS: This was a randomized, nonblinded, active-controlled, parallel-group clinical trial. Patients were randomly assigned to the 2 study groups, including treatment and control. Patients in the treatment group received povidone-iodine–impregnated antiseptic dressing applied to the anticipated incision site 12 hours before the operation. The control group merely received the standard perioperative care with no additional intervention or placebo. Patients were followed up for 90 days, and SSIs were recorded. RESULTS: A total of 200 patients were included in this study (100 in each arm). Three cases of SSI were observed in the treatment group compared with 12 in the control one. A significant reduction in the postoperative rate of SSI was observed in the treatment group compared with the control one (P = .029). In addition to study intervention (P = .029), body mass index (P = .005), smoking status (P = .005), duration of the procedure (P = .003), American Society of Anesthesiologists class (P = .002), and diabetes mellitus (P &lt; .001) were significantly associated with the postoperative rate of SSI. CONCLUSION: To the best of our knowledge, this study for the first time showed that preoperative use of antiseptic dressings is significantly effective in reducing the rate of SSI in instrumented posterior lumbar spinal fusion surgery. Future studies are warranted to evaluate the efficacy of different preparations or the effectiveness of the present one in patients undergoing spine procedures with other surgical characteristics.

Symptoms of sacral fractures after posterior spinal instrumented fusion: A case series

BackgroundImprovements in spinal fusion devices and techniques have enabled stronger spinal fusion, resulting in excellent clinical outcomes. Nevertheless, complications associated with implants, such as screw misalignment, screw lubrication, cage dislocation, and skin issues, might occur. This study aimed to investigate the characteristics and symptoms of sacral fractures after spinal instrumented fusion. MethodsThis case series retrospectively examined the medical records of eight patients (one man and seven women; mean age: 74 years) diagnosed with sacral fractures after undergoing posterior spinal instrumented fusion from February 2015 to March 2022. ResultsThe average number of fusion levels in all patients was 3.5 (range, 1–10). The lowest instrumented vertebrae (LIV) ranged from L5 to the ilium. Sacral fractures were diagnosed at 18.8 (range, 0.5–84) months postoperatively. The average time from consultation to diagnosis was nine days (range, 0–25 days). Two patients had subclinical fractures, two had H-shaped fractures with the LIV at L5, and four had U-shaped fractures, including screw holes. Buttock pain and lower extremity pain, the most commonly reported symptoms, were observed in seven patients each. There were also instances of leg numbness, muscle weakness, and unilateral leg pain that may be related to L5 or S1 radiculopathy. In all patients, leg and buttock pain were worse during movement and in the sitting position, and better while resting and in the supine position. Three patients were treated conservatively, and five were treated with extended fixation to the ilium. ConclusionsSacral fractures following posterior spinal fusion can cause radiculopathy and buttock pain. Symptoms are especially severe when instability occurs in the pelvic region, such as during movements or sitting. As atypical radiculopathy may lead to delays in diagnosis, spine surgeons should recognize the symptoms of this condition.

Long-term outcomes and complications of isolated anterior thoracolumbar fusion for neuromuscular scoliosis associated with myelomeningocele.

Neuromuscular scoliosis associated with myelomeningocele is a difficult clinical dilemma for the treating surgeon. The traditional surgical treatment consists of a posterior spinal instrumented fusion with or without a combined anterior procedure, but this has been associated with high complication rates, mostly related to deep infection. An anterior thoracolumbar fusion is not able to address the entirety of the deformity in many cases but could potentially avoid the devastating infection risks from the posterior approach by avoiding compromised skin. This study aims to evaluate the long-term outcomes and complications associated with isolated anterior thoracolumbar fusion in this high-risk group. This study is a retrospective analysis of patients with myelomeningocele-associated scoliosis treated with an isolated anterior spinal fusion over a 20-year time period at a single center. Surgical details, demographics, curve characteristics and complications were recorded. Comparisons were made between patients who required revision surgery and those who did not. Sixteen patients were enrolled with an average age of 12.7years at the time of surgery and average follow-up of 5.5years. Patients had on average 7.4 levels fused anteriorly with the most common levels being T10-L4. There were no deep wound infections associated with the anterior surgery. Overall, nine patients (56%) had to be revised posteriorly due to adding-on or junctional deformity at an average of 3.7years after index procedure. Four patients were revised due to proximal adding-on, while 1 was extended distally. Four additional patients were extended both proximally and distally. Of the posterior revisions, 2 patients developed deep wound infections, and both of these were in patients extended distally. Preoperative lumbar lordosis was higher in patients who required distal extension (100 vs. 69 degrees; p = 0.035). Patients undergoing isolated anterior fusion for scoliosis associated with myelomeningocele have low infection rates but often require posterior revision. The majority of patients can avoid the deep infection risk associated with distal posterior surgery at long-term follow-up. IV.

3D printed pedicle screw guides reduce the rate of intraoperative screw revision in adolescent idiopathic scoliosis surgery

Background ContextPedicle screw fixation has become common in the treatment of adolescent idiopathic scoliosis (AIS). Malpositioned pedicle screws have significant complications and identifying surgical techniques to optimize screw placement accuracy is imperative. PurposeTo compare the rate of intraoperative revision, replacement, or removal of pedicle screws placed utilizing 3D printed guides compared with pedicle screws placed utilizing a freehand technique. Study Design/SettingRetrospective cohort study/single academic center. Patient SampleThirty-two patients aged 10 to 18 with AIS. Outcome MeasuresRevision rate of pedicle screws and operative time between groups. MethodsA retrospective study was performed on patients 10 to 18 years of age who underwent posterior spinal instrumented fusion for AIS from February 2021 to July 2022. The study received an IRB exemption. Patient demographics, intraoperative measures, and outcome variables were recorded. Intraoperatively, all patients underwent a 3-dimensional fluoroscopic “check scan,” which included axial, sagittal, and coronal images, to assess for screw accuracy. A secondary outcome of operative time was compared between groups. The p-values <.05 were considered significant. ResultsA total of 32 patients were included in this study. There were 17 cases in the 3D guided and 15 cases in fluoroscopy-guided freehand cohort. There was a total of 254 pedicle screws using 3D guides and 402 screws using freehand technique. Between cohorts, there were no significant differences in a number of levels fused (p=.54) or length of surgery (p=.36). The total revision rate of 3D guided screw placement was 5.5% and that of the freehand technique was 8.5%. The freehand screw placement group had significantly higher revision rates per vertebral level compared with 3D guided (p=.0096). Notably, 3D printed guides had fewer screws that were removed/revised for being too anterior (7.1%) compared with freehand (23.5%). Surgical time was not significantly different between the 3D guided and freehand cohort (p=.35). Conclusions3D printed guides reduce intraoperative revision rate compared with freehand techniques. Total operative time is comparable to freehand technique.

Correlation of radiographic parameters and patient satisfaction in adolescent idiopathic scoliosis treated with posterior screw-dual-rod instrumentation.

In surgical treatment of adolescent idiopathic scoliosis (AIS), only a few studies measure both, radiological parameters and PROMs and correlate them. Prospectively collected AIS-data of one scoliosis-center within a multicenter German-Spine-Society-Study. All patients underwent instrumented posterior spinal correction and fusion with pedicle-screw-dual-rod-systems from 05/2019 to 01/2021. The data were retrospectively analyzed. age 11-17years, follow-up (FU) at least 12months. Clinical data, radiographic parameters, and PROMs (SRS-30-questionnaire) were collected. 100% of patients had X-ray images, 88.2% completed SRS-30. Parameters were given as mean ± SD. Differences and subdivision by lower instrumented vertebra (LIV) were analyzed by students t-test (significancy a = 0.05), associations by Pearson's correlation. Total of 51 patients: 15 ± 1.4years, BMI 20.7 ± 3.7kg/m2, FU 16.6 ± 6.1months, fusion length 9.2 ± 2.3 segments, implant density 93 ± 9%, surgical time 215 ± 71min, mean blood loss 504 ± 360ml. Mean preoperative Cobb angle of main curve 64 ± 14°, of secondary main curve 46 ± 12°, corrected by 68 ± 11%, 56 ± 17%, respectively. Mean thoracic rib and lumbar hump significantly decreased by -8.5 ± 7.0° and -7.7 ± 8.9° (p < 0.5). High thoracic rib hump almost unchanged, -0.4 ± 2.8° (p = 0.3). Thoracic kyphosis (-0.9 ± 12.8°, p = 0.6), lumbar lordosis (1.5 ± 10.1°, p = 0.3), clavicle angle (-0.5 ± 2.7°) and spinopelvic parameters (p > 0.5) did not significantly change, only LIV-tilt from 24.5 ± 6.7° to 6.5 ± 4.3° (p < 0.05). PROMs significantly improved (p < 0.05), no significant improvement for function/activity (p = 0.4). Preoperative mean total-score was 3.6 ± 0.5, 4.2 ± 0.3 at FU(p < 0.05). Self-image improved in 67%. Moderately strong correlation for PROMs: the better LIV-tilt (r = -0.5) correction and the shorter surgery time (r = -0.4), the better SRS-30 total-score. No correlation for curve correction and patient's satisfaction. In summary, results of this study demonstrate good surgical correction and significant improvement of most PROMs.

Risk factors for distal construct failure in posterior spinal instrumented fusion for adolescent idiopathic scoliosis: a retrospective cohort study.

To evaluate risk factors for distal construct failure (DCF) in posterior spinal instrumented fusion (PSIF) in adolescent idiopathic scoliosis (AIS). We hypothesise increased inferior angulation of the pedicle screw in the lowest instrumented vertebra (LIV) predisposes to failure and aim to find the critical angle that predisposes to failure. A retrospective cohort study was performed on all patients who underwent PSIF for AIS at our institution from 2010 to 2020. On lateral radiographs, the angle between the superior endplate of the LIV was measured against its pedicle screw trajectory. Data on demographics, Cobb angle, Lenke classification, instrumentation density, rod protrusion from the most inferior screw, implants and reasons for revision were collected. Of 256 patients, 9 patients had DCF with 3 further failures post-revision, giving 12 cases to analyse. The DCF rate was 4.6%. The mean trajectory angle of DCF patients compared to non-DCF was 13.3° (95% CI 9.2° to 17.4°) vs. 7.6° (7.0° to 8.2°), p = 0.0002. The critical angle is less than 11° (p = 0.0076), OR 5.15. Lenke 5 and C curves, lower preoperative Cobb angle, titanium only rod constructs and one surgeon had higher failure rates. 9.6% of rods protruding less than 3mm from its distal screw disengaged. Increased inferior trajectory of the LIV screw increases the rate of DCF; inferior trajectory greater than 11° predisposes to failure. Rod protrusion less than 3mm from the distal screw increases rate of disengagement. III.

Incidence and Recurrence of Deep Spine Surgical Site Infections: A Systematic Review and Meta-analysis.

Systematic review and meta-analysis. To determine a pooled incidence rate for deep surgical site infection (SSI) and compare available evidence for deep SSI management among instrumented spinal fusions. Deep SSI is a common complication of instrumented spinal surgery associated with patient morbidity, poorer long-term outcomes, and higher health care costs. We systematically searched Medline and Embase and included studies with an adult patient population undergoing posterior instrumented spinal fusion of the thoracic, lumbar, or sacral spine, with a reported outcome of deep SSI. The primary outcome was the incidence of deep SSI. Secondary outcomes included persistent deep SSI after initial debridement, mean number of debridements, and microbiology. The subsequent meta-analysis combined outcomes for surgical site infection using a random-effects model and quantified heterogeneity using the χ 2 test and the I2 statistic. In addition, a qualitative analysis of management strategies was reported. Of 9087 potentially eligible studies, we included 54 studies (37 comparative and 17 noncomparative). The pooled SSI incidence rate was 1.5% (95% CI, 1.1%-1.9%) based on 209,347 index procedures. Up to 25% of patients (95% CI, 16.8%-35.3%), had a persistent infection. These patients require an average of 1.4 (range: 0.8-1.9) additional debridements. Infecting organisms were commonly gram-positive, and among them, staphylococcus aureus was the most frequent (46%). Qualitative analysis suggests implant retention, especially for early deep SSI management. Evidence was limited for other management strategies. The pooled incidence rate of deep SSI post-thoracolumbar spinal surgery is 1.5%. The rate of recurrence and repeat debridement is at least 12%, up to 25%. Persistent infection is a significant risk, highlighting the need for standardized treatment protocols. Our review further demonstrates heterogeneity in management strategies. Large-scale prospective studies are needed to develop better evidence around deep SSI incidence and management in the instrumented thoracolumbar adult spinal fusion population.

TWO-YEAR FOLLOW-UP STUDY FOR PATIENTS UNDERGOING VERTEBRAL BODY TETHERING FOR IDIOPATHIC SCOLIOSIS

Anterior vertebral body tethering (AVBT) is a growth modulating procedure used to manage idiopathic scoliosis by applying a flexible tether to the convex surface of the spine in skeletally immature patients. The purpose of this study is to determine the preliminary clinical outcomes for an adolescent patient cohort.18 patients with scoliosis were selected using a narrow selection criteria to undergo AVBT. Of this cohort, 11 had reached a minimum follow up of 2 years, 4 had reached 18 months, and 3 had reached 6 months. These patients all demonstrated a primary thoracic deformity that was too severe for bracing, were skeletally immature, and were analysed in this preliminary study of coronal plane deformity correction.Using open-source image analysis software (ImageJ, NIH) PA radiographs taken pre-operatively and at regular follow-up visits post-operatively were used to measure the coronal plane deformity of the major and compensatory curves.Pre-operatively, the mean age was 12.0 years (S.D. 10.7 – 13.3), mean Sanders score 2.6 (S.D. 1.8-3.4), all Risser 0 and pre-menarchal, with mean main thoracic Cobb angle of 52° (S.D. 44.2-59.8°). Post-operatively the mean angle decreased to 26.4° (S.D. 18.4-32°) at 1 week, 30.4° (S.D. 21.3-39.6°) at 2 months, 25.7° (S.D. 18.7-32.8°) at 6 months, 27.9° (S.D. 16.2-39.6°) at 12 months, and 36.8° (S.D. 22.6– 51.0°) at 18 months and 38.2° (S.D. 27.6-48.7°) at 2 years. The change in curve at 2 years post-operative was statistically significant (P=0.004).There were 4 tether breakages identified that did not require return to theatre as yet, one patient underwent a posterior spinal instrumented fusion due to curve progression.AVBT is a promising new growth modulation technique for skeletally immature patients with progressive idiopathic scoliosis. This study has demonstrated a reduction in scoliosis severity.

Incisional Negative Pressure Wound Therapy Does Not Affect Deep Surgical Site Infection Rates in Neuromuscular Scoliosis Surgery.

Surgical site infection (SSI) is a devastating complication in patients with neuromuscular scoliosis (NMS) undergoing posterior spinal instrumented fusion (PSIF) for progressive scoliosis. Incisional negative pressure wound therapy (INPWT) has been used in other surgical fields to reduce SSI. Our purpose was to examine the prophylactic use of INPWT after NMS surgery to decrease SSI. At a single institution, 71 consecutive patients with NMS underwent PSIF from 2015 to 2019. Starting in 2017, all patients with NMS received INPWT postoperatively until discharge. Rates of deep SSI were compared between the two cohorts of patients. Additionally, patient demographic and operative factors such as American Society of Anesthesiologists score, number of levels instrumented, need for an anterior spinal release, need for spinal fusion to pelvis, blood loss, operative time, fluoroscopy time, length of stay, and transfusion requirement were analyzed for potential influence on deep SSI. There was no significant difference in deep SSI rates between patients who received INPWT (2 of 41) and those treated with a standard postoperative dressing (2 of 30; P=1.0). Although INPWT theoretically can stabilize the wound environment and prevent deep SSI, our findings do not support this. More research is needed to evaluate the efficacy of INPWT after PSIF for NMS. [Orthopedics. 2023;46(6):373-378.].

Can semirigid fixation of the rostral instrumented segments prevent proximal junctional kyphosis in the case of long thoracolumbar fusions? A finite element study.

Proximal junctional kyphosis (PJK) is a relatively common complication following long instrumented posterior spinal fusion. Although several risk factors have been identified in the literature, previous biomechanical studies suggest that one of the leading causes is the sudden change in mobility between the instrumented and noninstrumented segments. The current study aims to assess the biomechanical effect of 1 rigid and 2 semirigid fixation techniques (SFTs) on developing PJK. Four T7-L5 finite element (FE) models were developed: 1) intact spine; 2) 5.5-mm titanium rod from T8 to L5 (titanium rod fixation [TRF]); 3) multiple rods from T8 to T9 connected with titanium rod from T9 to L5 (multiple-rod fixation [MRF]); and 4) polyetheretherketone rod from T8 to T9 connected with titanium rod from T9 to L5 (PEEK rod fixation [PRF]). A modified multidirectional hybrid test protocol was used. First, a pure bending moment of 5 Nm was applied to measure the intervertebral rotation angles. Second, the TRF technique's displacement from the first loading step was applied to the instrumented FE models to compare the pedicle screw stress values in the upper instrumented vertebra (UIV). In the load-controlled step, at the upper instrumented segment, the intervertebral rotation values relative to TRF increased by 46.8% and 99.2% for flexion, by 43.2% and 87.7% for extension, by 90.1% and 137% for lateral bending, and by 407.1% and 585.2% for axial rotation, in the case of MRF and PRF, respectively. In the displacement-controlled step, maximum pedicle screw stress values at the UIV level were highest in the case of TRF (37.26 MPa, 42.13 MPa, 44.4 MPa, and 44.59 MPa for flexion, extension, lateral bending, and axial rotation, respectively). Compared to TRF, in the case of MRF and PRF, the screw stress values were reduced by 17.3% and 27.7% for flexion, by 26.6% and 36.7% for extension, by 6.8% and 34.3% for lateral bending, and by 49.1% and 59.8% for axial rotation, respectively. FE analysis has shown that the SFTs increase the mobility at the upper instrumented segment and therefore provide a more gradual transition in motion between the instrumented and rostral noninstrumented segments of the spine. In addition, SFTs decrease the screw loads at the UIV level and hence could help reduce the risk for PJK. However, further investigations are recommended to evaluate the long-term clinical usefulness of these techniques.

RISK FACTORS FOR DISTAL CONSTRUCT FAILURE IN POSTERIOR SPINAL INSTRUMENTED FUSION FOR ADOLESCENT IDIOPATHIC SCOLIOSIS: A RETROSPECTIVE COHORT STUDY

The purpose of this study is to evaluate risk factors for distal construct failure (DCF) in posterior spinal instrumented fusion (PSIF) in adolescent idiopathic scoliosis (AIS). We observed an increased rate of DCF when the pedicle screw in the lowest instrumented vertebra (LIV) was not parallel to the superior endplate of the LIV, however this has not been well studied in the literature. We hypothesise a more inferiorly angled LIV screw predisposes to failure and aim to find the critical angle that predisposes to failure.A retrospective cohort study was performed on all patients who underwent PSIF for AIS at the Starship Hospital spine unit from 2010 to 2020. On a lateral radiograph, the angle between the superior endplate of the LIV was measured against its pedicle screw trajectory. Data on demographics, Cobb angle, Lenke classification, instrumentation density, rod protrusion from the most inferior screw, implants and reasons for revision were collected.Of 256 patients, 10.9% (28) required at least one revision. The rate of DCF was 4.6% of all cases (12 of 260) and 25.7% of revisions were due to DCF. The mean trajectory angle of DCF patients compared to all others was 13.3° (95%CI 9.2° to 17.4°) vs 7.6° (7° to 8.2°), p=0.0002. The critical angle established is 11°, p=0.0076. Lenke 5 and C curves, lower preoperative Cobb angle, titanium only rod constructs and one surgeon had higher failure rates than their counterparts. 9.6% of rods protruding less than 3mm from its distal screw disengaged.We conclude excessive inferior trajectory of the LIV screw increases the rate of DCF and a screw trajectory greater than 11° predisposes to failure. This is one factor that can be controlled by the surgeon intraoperatively and by avoiding malposition of the LIV screw, a quarter of revisions can potentially be eliminated.

Sarcopenia and osteopenia are independent risk factors for proximal junctional disease after posterior lumbar fusion: Results of a retrospective study.

This was a retrospective study. Since a better understanding of modifiable risk factors for proximal junctional disease (PJD) may lead to improved postoperative outcomes and less need of revision surgery, the aim of the present study is to determine whether sarcopenia and osteopenia are independent risk factors for PJD in patients undergoing lumbar fusion. PJD is one of the most frequent complications following posterior instrumented spinal fusion. It is characterized by a spectrum of pathologies ranging from proximal junctional kyphosis (PJK) to proximal junctional failure (PJF). The etiology of PJD is multifactorial and currently not fully understood. Patient-specific factors, such as age, body mass index, osteoporosis, sarcopenia, and the presence of other comorbidities, can represent potential risk factors. A retrospective review of patients, aging 50-85 years, who underwent a short (≤3 levels) posterior lumbar fusion for degenerative diseases was performed. Through magnetic resonance imaging (MRI), central sarcopenia and osteopenia were evaluated, measuring the psoas-to-lumbar vertebral index (PLVI) and the M-score. A multivariate analysis was performed to determine the independent risk factors for PJD, PJK, and PJF. A total of 308 patients (mean age at surgery 63.8 ± 6.2 years) were included. Ten patients (3.2%) developed a PJD and all required revision surgery. Multivariate regression identified PLVI (P = 0.02) and M-score (P = 0.04) as independent risk factors for both PJK (P = 0.02 and P = 0.04, respectively) and PJF (P = 0.04 and P = 0.01, respectively). Sarcopenia and osteopenia, as measured by PLVI and M-score, proved to be independent risk factors for PJD in patients who undergo lumbar fusion for degenerative diseases. The present study was approved by the Institutional Review Board, CE AVEC 208/2022/OSS/IOR.

Perioperative Outcomes of Open Anterior Vertebral Body Tethering and Instrumented Posterior Spinal Fusion for Skeletally Immature Patients With Idiopathic Scoliosis.

Correcting adolescent idiopathic scoliosis (AIS) without fusion can be achieved with anterior vertebral body tethering (AVBT). However, little is known about the perioperative outcomes, pain control, and clinical outcomes in patients undergoing AVBT compared with instrumented posterior spinal fusion (IPSF). In this retrospective cohort study, we compared pediatric patients with AIS who underwent either AVBT or IPSF. Inclusion criteria were based on the AVBT group, which included primary thoracic idiopathic scoliosis, Risser ≤1, curve magnitude 40 to 70 degrees, age 9 to 15, no prior spine surgery, index surgery between 2014 and 2019, and minimum 2-year follow-up. Patient demographics, perioperative metrics, pain visual analog scale scores, opiate morphine equivalent usage, cost data, and radiographic outcomes were compared. We identified 23 patients who underwent AVBT and 24 matched patients in the IPSF group based on inclusion criteria. Patients undergoing AVBT and PSF were similar in age (12±1 y vs. 13±1 y, P =0.132) and average follow-up time (3.8±1.6 y vs. 3.3±1.4 y, P =0.210). There were 23 female patients (87%) in the AVBT group and 24 female (92%) patients in the IPSF group. Intraoperatively, estimated blood loss (498±290 vs. 120±47 mL, P <0.001) and procedure duration (419±95 vs. 331±83 min, P =0.001) was significantly greater in the IPSF group compared with AVBT. Length of stay was lower in the AVBT group compared with PSF (4±1 vs. 5±2 d, P =0.04). PSF patients had significantly greater total postoperative opiate morphine equivalent use compared with AVBT (2.2±1.9 vs. 5.6±3.4 mg/kg, P <0.001). Overall direct costs following PSF and AVBT were similar ($47,655+$12,028 vs. $50,891±$24,531, P =0.58). Preoperative radiographic parameters were similar between both the groups, with a major thoracic curve at 51±10 degrees for AVBT and 54±9 degrees for IPSF ( P =0.214). At the most recent follow-up, IPSF patients had greater curve reduction to a mean major thoracic curve of 11±7 degrees (79%) compared with 19±10 degrees (63%) in AVBT patients ( P =0.002). Nine patients (39%) required revision surgery following AVBT compared with 4 patients(17%) following IPSF ( P =0.09). In a select cohort of patients, AVBT offers decreased surgical time, blood loss, length of stay, and postoperative opiate usage compared with IPSF. Although IPSF resulted in greater deformity correction at 2-year follow-up, the majority of patients who underwent AVBT had ≤35 major curves and avoided fusion. There is optimism for AVBT as a treatment option for select AIS patients, but long-term complications are still being understood, and the risk for revision surgeries remains high. Level III.

What Radiographic and Clinical Factors Ultimately Necessitate a C2-Sacrum Instrumented Posterior Spinal Fusion?

/Hypothesis: Patients undergoing C2-sacrum PSF have unique medical histories and multiple prior operations over an extended period. Single center, retrospective cohort. Consecutive C2-sacrum PSF patients operated on by 4 surgeons at a single-center from 2015-2020 were reviewed. Demographics, comorbidities, indications, surgical history, and radiographic parameters were collected. 23 patients underwent C2-sacrum PSF. 13 (57%) were male, and 21 (91.3%) were adults. Mean age at time of first spine surgery was 44 years (range 5-71) and 53 years (range 14-72) at the time of C2-sacrum PSF. Six patients (26%) had osteoporosis, and 6 patients (26%) had neurologic comorbidities-including Parkinson's disease (4), cerebral palsy (1), and Brown Sequard syndrome (1). Four (17%) had connective tissue disease. Two patients underwent C2-sacrum PSF as an index procedure: (1) 67M with myelomatous fractures and 124° of cervicothoracic kyphosis; (2) 28F with severe Marfan syndrome with 140° thoracic scoliosis and 130° thoracic kyphosis. The remaining 21 (91%) underwent C2-sacrum PSF as a revision following prior spinal surgeries on average, 4 previous surgeries (range 1-13) over 10.5 years (range .3-37.4). Indications for the remaining 21 C2-sacrum PSF revision procedures included 17 (81%) for kyphosis (5 of whom also had significant coronal deformity), 1 (5%) for only coronal malalignment, 2 (10%) for instrumentation failure, and 1 (5%) for myelopathy. 91% (21/23) of patients requiring C2-sacrum PSF were treated as revisions of prior fusions, with a mean of 4 prior surgeries over 10 years. Over 80% of these patients underwent C2-sacrum PSF to address kyphosis. 26% had neurologic conditions, and 26% had osteoporosis.