Influence of curve magnitude and other variables on operative time, blood loss and transfusion requirements in adolescent idiopathic scoliosis

The effect of surgical time on perioperative complications in adolescent idiopathic scoliosis cases. A propensity score analysis

BACKGROUND

Posterior spinal instrumentation and fusion (PSIF) for adolescent idiopathic scoliosis (AIS) can be lengthy and complication-ridden. The aim of this study was to evaluate the effect of surgical time on perioperative complications in this procedure when controlling for confounding variables with propensity score analysis.

METHODS

This was an IRB-approved review of electronic health records from 2010 to 2019 at a single tertiary care children's hospital. Patients undergoing PSIF were grouped into "short" (< 6 h) or "long" (≥ 6 h) surgical time groups. Outcome measures were estimated blood loss (EBL), cell saver transfusions, packed red blood cell (pRBC) transfusions, length of stay (LOS), intraoperative monitoring (IOM) alerts, hematocrit, ICU transfer, neurologic loss, surgical site infection, and 90-day readmissions. We controlled for age, sex, BMI, curve severity, number of segments fused, and surgeon factors.

RESULTS

After propensity score matching there were 113 patients in each group. The short surgical time group had lower EBL (median 715, IQR 550-900 vs median 875, IQR 650-1100 cc; p < 0.001), received less cell saver blood (median 120, IQR 60-168 vs median 160, IQR 97-225 cc; p = 0.001), received less intraoperative pRBCs (median 0, IQR 0-0 vs median 0, IQR 0-320, p = 0.002), had shorter average LOS (4.8 ± 1.7 vs 5.4 ± 2.5 days; p = 0.039), and fewer IOM alerts (4.3% vs 18%, p = 0.003).

CONCLUSIONS

Patients with shorter surgical times had less blood loss, received less transfused blood, had a shorter LOS, and fewer IOM alerts compared to patients with longer surgical times. Surgical times < 6 h may have safety and efficacy advantages over longer times.

LEVEL OF EVIDENCE

III.

Analysis of duration of different stages of surgery in posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) patients: comparison between severe versus non-severe AIS

PURPOSE

Prolonged surgical duration in severe adolescent idiopathic scoliosis (AIS) patients is associated with increased blood loss and perioperative complications. The aim of this study was to compare the duration of each stage of posterior spinal fusion (PSF) in severe AIS (Cobb angle ≥ 90°) with non-severe AIS patients. This analysis will identify the most time-consuming stage of PSF and help surgeons formulate strategies to shorten operative time.

METHODS

Retrospective study whereby 90 AIS patients (Lenke type 2, 3, 4, and 6) who underwent PSF from 2019 to 2023 were recruited. Twenty-five severe AIS patients were categorized in Gp1 and 65 non-severe AIS patients in Gp2. Propensity score matching (PSM) with one-to-one with nearest neighbor matching (match tolerance 0.05) was performed. Outcomes measured via operation duration of each stage of surgery, blood loss, number of screws, fusion levels and screw density.

RESULTS

Twenty-five patients from each group were matched. Total operative time was significantly higher in Gp1 (168.2 ± 30.8 vs. 133.3 ± 24.0 min, p < 0.001). The lengthiest stage was screw insertion which took 58.5 ± 13.4 min in Gp1 and 44.7 ± 13.7 min in Gp2 (p = 0.001). Screw insertion contributed 39.5% of the overall increased surgical duration in Gp1. Intraoperative blood loss (1022.2 ± 412.5 vs. 714.2 ± 206.7 mL, p = 0.002), number of screws (17.1 ± 1.5 vs. 15.5 ± 1.1, p < 0.001) and fusion level (13.1 ± 0.9 vs. 12.5 ± 1.0, p = 0.026) were significantly higher in Gp1.

CONCLUSION

Screw insertion was the most time-consuming stage of PSF and was significantly longer in severe AIS. Adjunct technologies such as CT-guided navigation and robotic-assisted navigation should be considered to reduce screw insertion time in severe AIS.

Postoperative complications following Schwab-grade-I versus Schwab-grade-II PCO in treating severe rigid kyphoscoliosis patients: comparative matched-group outcomes with minimum 2-year follow-up

BACKGROUND CONTEXT

Standard partial facetectomies, (Smith-Petersen Osteotomy, (SPO), (Schwab-grade-I) and complete facet resection also known as Ponte osteotomy, (PO), (Schwab-grade-II) are narrowly akin and collectively appreciated as posterior column shortening osteotomies (PCOs). The former is considered a gentler osteotomy grade than the latter. The spine literature provides very little information on their comparison regarding perioperative complications and major curve correction rate outcomes.

PURPOSE

To determine whether Schwab-grade-I PCO (SPO) and Schwab-grade-II PCO (PO) are comparably safe in the surgical management of severe rigid scoliosis or kyphoscoliosis patients.

STUDY DESIGN/SETTING

Retrospective single-center comparative clinical study.

PATIENT SAMPLE

A total of 38 patients with severe rigid scoliosis or kyphoscoliosis were propensity score matched in this study, (SPO-treated); n=21 (55.30%) and (PO-treated); n=17 (44.70%), who underwent primary spinal deformity corrective surgery, respectively.

OUTCOME MEASURES

Outcomes included demographics, baseline pulmonary functional outcomes, perioperative complications incidence, hospital costs, Oswestry disability index (ODI), and the Scoliosis Research Society-22 (SRS-22) questionnaire scores.

METHODS

Following approval by the Institutional Review Board (IRB) of Beijing Chaoyang Hospital-Affiliated Capital Medical University in Beijing, out of a total of 82 consecutive surgical patients with complete data demonstrating severe and/or rigid spinal deformity, a pool of 38 of the 82 (46.3%) propensity-matched adult (≥18 years) patients with severe rigid scoliosis or kyphoscoliosis defined with a preoperative major curve magnitude of ≥80° on anteroposterior plain radiographs, and flexibility of <25% on bending plain radiographs who underwent primary spinal deformity corrective surgery were retrospectively evaluated. The patients were dichotomized into two osteotomy groups: standard (partial) facetectomy (SPO-treated), n=21 with an average age of 24.67 years, (Schwab-grade-I PCO) and complete facet excision, (PO-treated), (ie, Schwab-grade-II PCO), n=17 with an average age of 23.12 years. The minimum follow-up period was 2 years. Primary outcomes included baseline demographics and clinical features. Secondary outcomes included perioperative [intraoperative, immediate, and 2-year postoperative] complication rates. Tertiary outcomes included perioperative ODI and SRS-22 scores. Statistical analyses were carried out by Student t-test and Pearson's Chi-square test (Fisher's Exact Test), through Python statistical software package. Statistical significance was set at (p<.05).

RESULTS

Of the 38 matched severe rigid scoliosis or kyphoscoliosis patients, 55.30% (n=21) were SPO-treated and 44.70% (n=17) were PO-treated patients, respectively. The overall average age of patients was 23.97 years, with a female incidence of 76.32%. Major curve correction rates were 49.19% and 57.40% in SPO-treated and PO-treated patients, respectively, (p>.05). Immediately following surgery, comparable overall complication rates of 28.57% (n=6/21) versus 29.41% (n=5/17) were observed in the SPO-treated and PO-treated patients, respectively, (p=.726). We observed incidences of 9.52%, (n=2/21) versus 5.88%, (n=1/17) for surgical intensive care unit (SICU) admission, and incidences of 4.76%, (n=1/21) versus 5.88%, (n=1/17) for cardiopulmonary events in SPO-treated versus PO-treated patients following corrective surgery, respectively, (p>.05). The incidences of neurological deficits in the SPO-treated and PO-treated patients were respectively, 14.29%, (n=3/21) versus 17.65%, (n=3/17) immediately following surgery, (p>.05), and 0.00%, (n=0/21) in SPO-treated versus 14.28%, (n=3/21) in PO-treated patients at ≥2 years postoperative, (p<.05). Among the three patients that reported neurological deficits in the PO-treated group at ≥2 years postoperative, two patients had pre-existing baseline neurological deficits. The ODI score in the PO-treated group was significantly inferior at a minimum 2-year follow-up, (p<.05).

CONCLUSIONS

In the current study, both SPO-treated and PO-treated patients demonstrated statistically comparable surgical complications immediately following corrective surgery. Severe rigid kyphoscoliosis patients with preexisting baseline neurological deficits were more inclined to sustain neurological morbidity following corrective surgery. PCO corrective techniques are warranted as safe options for treating patients with severe rigid spine deformity phenotypes.

Intraoperative Blood Loss at Different Surgical-Procedure Stages during Posterior Spinal Fusion for Idiopathic Scoliosis

Background and Objectives: Several predictive factors have been reportedly associated with intraoperative total blood loss (TBL) during posterior spinal fusion (PSF) for idiopathic scoliosis (IS). To reduce TBL, preoperative factors and interoperative factors are considered important. However, there are few reports that have evaluated bleeding patterns according to surgical stages. This study aimed to elucidate bleeding patterns at different surgical stages and determine the predictive factors for TBL during PSF surgery in patients with IS. Materials and Methods: Preoperative data, radiographic parameters, and intraoperative data of patients undergoing PSF for IS were retrospectively collected. We divided the patients into six stages: stage 1, exposure; stage 2, implant placement; stage 3, release; stage 4, correction; stage 5, bone grafting; and stage 6, closure; then we reviewed the blood loss and bleeding speed. Multiple-regression analysis was performed to generate a predictive formula for blood loss using preoperative and intraoperative factors, including blood loss at stage 1, as explanatory variables. Results: Forty-five patients (mean age: 17.6 years) were included. The mean operative time and TBL were 287.9 min and 756.5 mL, respectively. Blood loss was the highest at stage 3, followed by stage 4. Bleeding speed was the highest at stage 4, followed by stage 3. Bleeding speeds at stages 3 and 4 were significantly higher than those at stages 1 and 2. Preoperative Cobb angle, activated partial thromboplastin time (aPTT), number of fused vertebrae, and blood loss at stage 1 were significant contributing factors. Conclusions: Blood loss and bleeding speed during the release and correction stages were high. Specifically, bleeding speed significantly increased during and after the release procedure. The preoperative Cobb angle, aPTT, number of fixed vertebrae, and blood-loss volume during PSF were significantly associated with TBL. Our findings would be helpful for reducing TBL in patients undergoing PSF for IS.

Operative time in adolescent idiopathic scoliosis surgery: a need for a standard definition

Our objective is to report and define 'operative time' in adolescent idiopathic scoliosis (AIS) posterior spinal fusion surgeries. Documenting key times during surgery are important to compare operative risks, assess learning curves, and evaluate team efficiency in AIS surgery. 'Operative time' in literature has not been standardized. Systematic review was performed by two reviewers. Keywords included operative time, duration of surgery, and scoliosis. One thousand nine hundred six studies were identified, 1092 duplicates were removed and 670 abstracts were excluded. Of the 144 articles, 67 met inclusion and exclusion criteria. Studies were evaluated for number of patients, operative time, and definition of operative time. Meta-analysis was not performed due to confounders. Of the 67 studies (6678 patients), only 14 (1565 patients) defined operative time, and all specified as incision to closure. From these 14 studies, the median operative time was 248 minutes (range 174-448 minutes). In the 53 studies (5113 patients) without a definition, one study reported time in a non-comparable format, therefore, data were analyzed for 52 studies (5078 patients) with a median operative time of 252 minutes (wider range 139-523 minutes). A clear standardized definition of operative or surgical time in spine surgery does not exist. We believe that operative time should be clearly described for each published study for accurate documentation and be defined from incision time to spine dressing completion time in order to standardize study results. Level of evidence: IV.

The efficacy and safety of intraoperative acute normovolaemic haemodilution in complex spine surgery in a private surgical facility in Ghana

Objectives

To assess the safety and clinical benefits of intraoperative acute normovolaemic haemodilution (ANH) in complex spine surgery.

Design

Prospective comparative cohort study.

Setting

A private orthopaedic hospital in Ghana.

Patients

Seventy-six patients who underwent complex spine deformity surgery.

Interventions

Patients were randomly assigned to two groups. 45 patients to the acute normovolaemic haemodilution (ANH) or Group 1 and 31patients to the non-ANH or Group 2. Following anesthetic administration and before incision, autologous blood was collected from patients in Group1 and was reinfused during/shortly after surgery while patients in Group2 were transfused with compatible allogeneic blood intraoperatively.

Main Outcome Measures

Changes in haemodynamic parameters and incidence of allogeneic transfusions and related complications.

Results

The mean age (years), gender ratio, deformity size and aetiology, fusion levels, and operative times were similar in both groups. Blood loss (ml) of patients in groups 1 and 2 were 1583ml± 830.48 vs 1623ml ± 681.34, p=0.82, respectively. The rate of allogeneic blood transfusion in groups 1 and 2 were 71% vs 80.65%, p=0.88, respectively. Haemoglobin levels (g/dL) in groups 1 and 2 were comparable in both groups at Post-operative Day (POD) 0 and POD 1. Incidence of minor allogeneic transfusion reaction was 1/45 vs 1/31, p=0.80, group-1 and group-2, respectively.

Conclusion

Acute normovolaemic haemodilution can be safely performed in complex spine surgery in underserved regions. However, its use does not obviate allogeneic transfusion in patients with complex spine deformities in whom large volumes of blood loss is expected.

Funding

None declared.

Thoracic Lordosis, Especially in Males, Increases Blood Loss in Adolescent Idiopathic Scoliosis

BACKGROUND

Intraoperative blood loss during posterior spinal fusion for adolescent idiopathic scoliosis (AIS) has been reportedly associated with multiple factors. This study aims to investigate the effect of thoracic kyphosis on blood loss in AIS spinal fusion.

METHODS

Patients with AIS who underwent posterior-only procedures for Lenke I and II type curves were identified. All included patients had intraoperative tranexamic acid. Difference in estimated blood loss per blood volume (EBL/BV) was identified between hypokyphotic curves (-), normal curves (N), and hyperkyphotic curves (+) classified based on Lenke sagittal modifier. Regression analysis was then performed with EBL/BV as dependent variable. Independent variables included radiographically measured T5-T12 kyphosis and calculated 3D T5-T12 kyphosis in addition to sex, body mass index (BMI), operative time, number of fused vertebrae, number of Ponte osteotomy levels, and main thoracic coronal curve.

RESULTS

In total, 837 patients were included. For female patients: EBL/BV was significantly higher for (-) (18%) compared with (N) (16%) and (+) (14%). A total of 29 female patients had T5-T12≤0 (-15 to 0 degree). EBL/BV was not significantly higher than patients with T5-T12>0 degree (18%±9% vs. 16%±11%; P=0.212). For male patients: EBL/BV was significantly higher in (-) (23%) compared with (+) (16%). In total, 14 male patients had T5-T12≤0 (-13 to 0) degree. EBL/BV was significantly higher than patients with T5-T12>0 degree (32%±18% vs. 18%±13%; P=0.015). Significant factors in predicting EBL/BV were sex, BMI, number of fused levels, and both 2D and 3D T5-T12 kyphosis. Male sex as well as every fused-level predicted an increase in EBL/BV~2%. Every 10-unit decrease in BMI predicted an increase in EBL/BV of 7%. Every 10-degree decrease in 2D or 3D T5-T12 kyphosis predicted an increase in EBL/BV~1%. The impact of the number of Ponte osteotomy levels was not significant.

CONCLUSIONS

This study supports the role of sagittal thoracic alignment in affecting EBL/BV in AIS surgery. Male patients with severe thoracic lordosis (T5-T12≤0 degree) are the highest risk group for intraoperative bleeding. These findings are helpful in predicting the intraoperative blood loss for patients with AIS undergoing posterior spinal fusion. In addition to sex and number of fused levels, decreased thoracic kyphosis is associated with increased blood loss.

LEVEL OF EVIDENCE

Level III-prognostic study.

Blood Loss Trends and Financial Implications in Adolescent Idiopathic Scoliosis

STUDY DESIGN

This was a retrospective cohort study.

OBJECTIVE

The primary goal was to evaluate risk factors related to increased blood loss in adolescent idiopathic surgery (AIS) surgery with the secondary goal being to evaluate the financial implications around the use of intraoperative cell salvage (ICS) and the routine preallocation of autogenous blood products.

SUMMARY OF BACKGROUND DATA

Deformity correction for AIS is a complex procedure and can be associated with significant blood loss.

METHODS

A retrospective cohort study was conducted on consecutive patients between the ages of 10 and 18 years who underwent posterior spinal fusion of 7-12 levels over a 3-year period between January 2013 and December 2015. Demographic information and surgical characteristics were recorded. All patients had a preoperative type and cross of 2 units and ICS was used in all cases. Charges for preoperative type and cross and ICS were also measured. Univariate and multivariable analyses were performed to identify pertinent variables affecting blood loss.

RESULTS

In total, 134 patients met inclusion criteria. ICS was used in all cases. In total, 51 patients were transfused cell saver blood intraoperatively/postoperatively at the discretion of the surgeon. On average 133 mL were returned to the patient. No complications related to ICS were observed. Multivariable analysis identified male sex, lower body mass index and higher surgical time to be associated with increased blood loss (P<0.05). All 134 patients had a preoperative type and cross, with an average charge to patient of $311. Patients were charged $1037 for intraoperative use of ICS and $242 for centrifugation. Patients who had allogeneic transfusion were charged $1047.

CONCLUSIONS

Several blood conservation strategies, including use of ICS, exist to minimize the consequences of blood loss. Routine use of preoperative type and cross may be avoided except in cases where significant blood loss is anticipated-that is adolescent male individuals, those with a lower body mass index and in whom a longer surgical time is anticipated.

Predicting massive transfusion in adolescent idiopathic scoliosis patients undergoing corrective surgery: Association of preoperative radiographic findings

Corrective surgery with a posterior approach for adolescent idiopathic scoliosis (AIS) is often accompanied by considerable bleeding. Massive transfusion after excessive hemorrhage is associated with complications such as hypothermia, coagulopathy, and acid-base imbalance. Therefore, prediction and prevention of massive transfusion are necessary to improve the clinical outcome of AIS patients. We aimed to identify the factors associated with massive transfusion in AIS patients undergoing corrective surgery. We also evaluated the clinical outcomes after massive transfusion.We included and analyzed AIS patients who underwent corrective surgery with a posterior approach from January 2008 to February 2015. We retrospectively reviewed the electronic medical records of 765 consecutive patients. We performed multivariable logistic regression analysis to assess the factors related to massive transfusion. Furthermore, we compared the effects of massive transfusion on clinical outcomes, including postoperative morbidity and hospital stay.Of 765 patients, 74 (9.7%) received massive transfusion. Body mass index (odds ratio [OR] 0.782, 95% confidence interval [CI] 0.691-0.885, P < .001) and the number of fused vertebrae (OR 1.322, 95% CI 1.027-1.703, P = .03) were associated with massive transfusion. In the comparison among the different Lenke curve types, Lenke type 4 showed the highest prevalence of massive transfusion. Patients in the massive transfusion group showed a higher incidence rate of postoperative morbidity and prolonged hospital stay.Massive transfusion was required in 9.7% of AIS patients who underwent corrective surgery with a posterior approach. A lower body mass index and higher number of fused vertebrae were associated with massive transfusion. Massive transfusion is related to poor clinical outcomes in AIS patients.

The Effect of Two Attending Surgeons on Patients With Large-Curve Adolescent Idiopathic Scoliosis Undergoing Posterior Spinal Fusion

STUDY DESIGN

Retrospective, chart review.

OBJECTIVES

The objective of this study is to investigate the impact of using two surgeons for posterior spinal fusion (PSF) in patients with AIS with large-magnitude curves (greater than 70°).

SUMMARY OF BACKGROUND DATA

Previous studies have shown that intraoperative risk factors can be reduced by having two surgeons operate simultaneously.

METHODS

A retrospective chart review identified 47 patients between January 1, 2009, and December 31, 2014, who underwent a posterior spinal fusion (PSF) with AIS with large-magnitude curves (greater than 70°). Patients with large-magnitude curves due to neuromuscular diseases or any defined pathology other than idiopathic scoliosis were excluded, as well as patients with kyphotic or kyphoscoliotic curves.

RESULTS

There was no statistical difference between the total operative time, anesthesia time, estimated blood loss (EBL), %EBL, and blood transfusion units. Total operative time for the two-surgeon group and single-surgeon group was 212.11 and 238.07 minutes, respectively (p = .078). The two-surgeon group averaged 0.26 blood transfusion units versus 0.39 units for the single-surgeon group (p = .50). Average hospital length of stay was decreased in the two-surgeon group (5.16 vs. 6.82 days, p = .002).

CONCLUSIONS

The use of two surgeons for PSF for AIS has previously been shown to decrease operative time and blood loss, factors that are correlated with prolonged hospital stay and increased risk of both neurologic and nonneurologic complications. However, in this study, the technique of having two experienced orthopedic spine surgeons work simultaneously to perform pedicle screw-only posterior spinal fusion on large-magnitude AIS curves greater than 70° did not improve blood loss or operative time. Further study needs to continue to identify ways to minimize complications for patients who undergo spinal fusion.

LEVEL OF EVIDENCE

Level III, retrospective, comparative study.

Blood transfusion in the surgical treatment of adolescent idiopathic scoliosis-a single-center experience of patient blood management in 210 cases

BACKGROUND

The surgical treatment of adolescent idiopathic scoliosis can be associated with substantial blood loss, requiring allogeneic red blood cell (RBC) transfusion. This study describes the use of RBC and the effect of a standardized perioperative patient blood management program.

STUDY DESIGN AND METHODS

Patients treated with posterior instrumented fusion were consecutively enrolled over a 6-year period. Patient blood management strategies were implemented in 2011, including prophylactic tranexamic acid, intraoperative permissive hypotension, restrictive fluid therapy (including avoidance of synthetic colloids), restrictive RBC trigger according to institutional standardized protocol, the use of cell savage, and goal-directed therapy according to thrombelastography.

RESULTS

In total, 210 patients were included. 64 patients (31%) received RBC transfusions. A decline in the intraoperative rate of RBC transfusion was observed, from 77% in 2011 to 13% in 2016 (p < 0.001). Patients in the transfusion group had a significantly larger major curve, lower preoperative hemoglobin, higher estimated blood loss, and an increased use of crystalloid volume resuscitation. Multiple logistic regression showed that significant predictors for RBC transfusion were preoperative hemoglobin level (odds ratio [OR], 0.40; 95% confidence interval [CI], 0.27-0.57), estimated blood loss (OR, 1.26; 95% CI, 1.15-1.42), and year of surgery (indicating the effect of patient blood management) (OR per year, 0.76; 95% CI, 0.58-0.99).

CONCLUSION

A perioperative patient blood management program substantially reduced the need for RBC transfusion. A preoperative evaluation of anemia is essential to further minimize transfusion rates.