Cost minimization in treatment of adult degenerative scoliosis

Do peri-operative parathyroid hormone (PTH) analogues improve bone density and decrease mechanical complications in spinal deformity correction?-a minimum 2-year radiological study measuring Hounsfield units

OBJECTIVE

To delineate whether use of a PTH analogue in the 1-year peri-operative period improves lumbar bone density.

METHODS

A prospectively collected data registry of 254 patients who underwent CMIS correction of ASD (Cobb angle > 20 or SVA > 50 mm or (PI-LL) > 10) from Jan 2011 to Jan 2020 was analysed. Patients who were placed on PTH analogues for one year in conjunction with surgery were included in the study. Ultimately, 41 patients who had pre- and two-year post-operative CT scans for review were included in this study. Hounsfield units were measured off of the L1-L3 levels for all patients before and after surgery on pre-op and post-op CT scans.

RESULT

The mean age of patients in this study was 70 (52-84, SD 7). Mean follow-up was 66 (24-132, SD 33) months. Twenty-three patients met criteria for severe deformity (Cobb angle > 50 degrees or SVA > 95 mm or PI/LL mismatch > 20 or PT > 30). Based off 2-year post-op CT scan, there were significant improvements in L1 Hounsfield units when comparing pre-op values (96; SD 55) to post-op values (185 SD 102); p. < 0.05. There was no screw loosening or screw pull out. There were 2 patients with PJF (4.8%). Both these patients had not completed their PTH treatment: one only took PTH for 3 months (PJF at 2-year post-op) and the other one took it only for 1 month (PJF at 1-year post-op). No increase in bone density was noted (based off of Hounsfield units) in five patients (12%) despite completion of their PTH therapy. Only one patient experienced nausea from PTH therapy. There were no other PTH related adverse events.

CONCLUSION

The incidence of PTH analogues failing to increase bone density in our series was low at 12%. This study shows that PTH analogues may be a powerful adjunct for increasing bone density and may help to mitigate the risk of mechanical complications in patients undergoing deformity correction with minimally invasive techniques. Future comparative studies are warranted to confirm these latter findings and to potentially protocolize the ideal peri-operative bone health optimization strategy.

Return to work after adult spinal deformity surgery

PURPOSE

To determine the proportions of patients returning to work at various points after adult spinal deformity (ASD) surgery and the associations between surgical invasiveness and time to return to work.

METHODS

Using a multicenter database of patients treated surgically for ASD from 2008 to 2015, we identified 188 patients (mean age 51 ± 15 years) who self-reported as employed preoperatively and had 2-year follow-up. Per the ASD-Surgical and Radiographical Invasiveness Index (ASD-SR), 118 patients (63%) underwent high-invasiveness (HI) surgery (ASD-SR ≥ 100) and 70 (37%) had low-invasiveness (LI) surgery (ASD-SR < 100). Patients who self-reported ≥ 75% normal level of work/school activity were considered to be working full time. Chi-squared and Fisher exact tests were used to compare categorical variables (α = .05).

RESULTS

Preoperatively, 69% of employed patients worked full time. Postoperatively, 15% of employed patients were full time at 6 weeks, 70% at 6 months, 83% at 1 year, and 84% at 2 years. Percentage of employed patients working full time at 2 years was greater than preoperatively (p < .001); percentage of patients returning to full time at 6 weeks was lower in the HI (5%) than in the LI group (19%) (p = .03), a difference not significant at later points.

CONCLUSIONS

Most adults returned to full-time work after ASD surgery. A smaller percentage of patients in the HI group than in the LI group returned to full-time work at 6 weeks. Patients employed full time preoperatively will likely return to full-time employment after ASD surgery.

LEVEL OF EVIDENCE

III.

Paraspinal muscle approach for neuromuscular scoliosis: A comparative study evaluating deformity correction and perioperative morbidity in 91 patients with minimum 2-year follow-up

PURPOSE

We present the paraspinal approach use for neuromuscular scoliosis with focus on deformity correction, perioperative (≤30 days) morbidity and outcome at a minimal follow-up length of 2 years.

METHODS

We prospectively collected data of 61 neuromuscular scoliosis patients operated using a paraspinal (Wiltse) approach between 2013 and 2019. We additionally collected data of 104 control cases, operated using a midline approach between 2005 and 2016. Fifteen Wiltse, respectively 37 control patients were excluded due to a short follow-up (<2 years), and 22 controls were excluded secondary to lacking follow-up data. Hence, 46 Wiltse and 45 control patients were compared.

RESULTS

Wiltse and control patients had comparable follow-up lengths, demographics, deformity corrections, complication rates, number of levels fused, and intensive care unit and hospital lengths of stay. Wiltse cases had a lower estimated blood loss (535 vs 1187 mL; p-value < 0.001), allogenic transfusion rate (48% vs 96%; p-value < 0.001), and operating time (ORT) (337 vs 428 min; p-value < 0.001) than controls. This was also the case when selecting for patients without pelvic fixation (p-values < 0.001). When selecting the cases with pelvic fixation (20 among 91 cases), only the number of levels fused and the ORT differed significantly according to the approach (p-value <0.015 and <0.041).

CONCLUSION

The paraspinal approach for neuromuscular scoliosis is safe, associated with significant deformity correction, reduced estimated blood loss, and allogenic transfusion rate. These potential benefits still need to be evaluated, especially for cases with pelvic fixation, with further follow-up of larger cohorts.

LEVEL OF EVIDENCE

level III.

Neuromuscular Scoliosis: A Dual-Surgeon Approach

OBJECTIVE

Neuromuscular Scoliosis (NMS) causes severe deformity and operative correction for these patients carries high complication rates. We present a retrospective study comparing a series of consecutive patients who underwent posterior fusion via a single-surgeon (SS) approach with a consecutive series of patients treated via a dual-surgeon (DS) approach.

METHODS

Patients with NMS who underwent posterior fusion via a SS approach from 2019 to 2022 were analyzed and compared to a series of patients with NMS who underwent posterior fusion via a DS approach.

RESULTS

In the SS group, the average estimated blood loss (EBL) was 675 mL, average length of stay (LOS) was 6.3 days, average operative time (OT) was 6.5 hours, average packed red blood cell transfusion was 1.5 units, with a complication rate of 30%. The DS group had an average EBL of 400 mL, a LOS of 4.8 days, an OT of 4.75 hours, an average packed red blood cell transfusion of 0.8 units, with a complication rate of 20%. The DS approach was significant for a lower EBL, OT (P < 0.001), and LOS (P < 0.03).

CONCLUSIONS

This study suggests that for patients with NMS the DS approach decreases OT, EBL, complication rates, and LOS. This further supports that this approach may benefit outcomes in NMS patients.

[Biomechanical evaluation of effects of percutaneous cement discoplasty and percutaneous cement interbody fusion on spinal stability]

OBJECTIVE

To investigate the effects of percutaneous cement discoplasty (PCD) and percutaneous cement interbody fusion (PCIF) on spinal stability by in vitro biomechanical tests.

METHODS

Biomechanical test was divided into intact (INT) group, percutaneous lumbar discectomy (PLD) group, PCD group, and PCIF group. Six specimens of L _{4, 5} (including vertebral bodies and intervertebral discs) from fresh male cadavers were taken to prepare PLD, PCD, and PCIF specimens, respectively. Before treatment and after the above treatments, the MTS multi-degree-of-freedom simulation test system was used to conduct the biomechanical test. The intervertebral height of the specimen was measured before and after the axial loading of 300 N, and the difference was calculated. The range of motion (ROM) and stiffness of the spine in flexion, extension, left/right bending, and left/right rotation under a torque of 7.5 Nm were calculated.

RESULTS

After axial loading, the change of intervertebral height in PLD group was more significant than that in other three groups ( P<0.05). Compared with INT group, the ROM in all directions significantly increased and the stiffness significantly decreased in PLD group ( P<0.05). Compared with INT group, the ROM of flexion, extension, and left/right rotation in PCD group significantly increased and the stiffness significantly decreased ( P<0.05); compared with PLD group, the ROM of flexion, extension, and left/right bending in PCD group significantly decreased and the stiffness significantly increased ( P<0.05). Compared with INT group, ROM of left/right bending in PCIF group significantly decreased and stiffness significantly increased ( P<0.05); compared with PLD group, the ROM in all directions significantly decreased and the stiffness significantly increased ( P<0.05); compared with PCD group, the ROM of flexion, left/right bending, and left/right rotation significantly decreased and stiffness significantly increased ( P<0.05).

CONCLUSION

Both PCD and PCIF can provide good biomechanical stability. The former mainly affects the stiffness in flexion, extension, and bending, while the latter is more restrictive on lumbar ROM in all directions, especially in bending and rotation.

Systematic review and meta-analysis for the impact of rod materials and sizes in the surgical treatment of adult spine deformity

PURPOSE

To assess clinical and safety outcomes associated with different rod materials and diameters in adult spinal deformity (ASD) surgery.

METHODS

A systematic literature review and meta-analysis evaluated ASD surgery using pedicle screw fixation systems with rods of different materials and sizes. Postoperative outcomes (i.e., Cobb, sagittal vertical axis, and pelvic tilt angle) and complications (i.e., pseudarthrosis and rod breakage) were assessed. Random effects models (REMs) pooled data for outcomes reported in ≥ 2 studies.

RESULTS

Among 50 studies evaluating ASD surgery using pedicle screw fixation systems, 17 described rod material/diameter. Postoperative outcomes did not statistically differ between cobalt-chromium (CoCr) vs. titanium (Ti) rods (n = 2 studies; mean [95% confidence interval (CI)] sagittal vertical axis angle: CoCr 37.00° [18.58°-55.42°] and Ti 32.58° [24.62°-40.54°]; mean [95% CI] pelvic tilt angle: CoCr 26.20° [22.87°-29.53°] and Ti 20.15° [18.0°-22.31°]). The pooled proportion (95% CI) of pseudarthrosis was 15% (7-22%) for CoCr and 12% (- 8-32%) for stainless steel (SS) (n = 2 studies each; Chi2 = 0.07, p = 0.79). The pooled proportion (95% CI) of broken rods was 12% (1-22%) for Ti (n = 3 studies) and 10% (2-19) for CoCr (n = 1 study). Among 6.0-6.35 mm rods, the pooled (95% CI) postoperative Cobb angle (n = 2) was 12.01° (9.75°-14.28°), sagittal vertical axis angle (n = 4) was 35.32° (30.02°-40.62°), and pelvic tilt angle was 21.11° (18.35°-23.86°).

CONCLUSIONS

For ASD patients undergoing posterior fixation and fusion, there are no statistically significant differences in postoperative outcomes or complications among rods of varying materials and diameters. Benchmark postsurgical outcomes and complication rates by rod material and diameter are provided.

LEVEL OF EVIDENCE

III.

An ex-vivo model for the biomechanical assessment of cement discoplasty

Percutaneous Cement Discoplasty (PCD) is a surgical technique developed to relieve pain in patients with advanced degenerative disc disease characterized by a vacuum phenomenon. It has been hypothesized that injecting bone cement into the disc improves the overall stability of the spinal segment. However, there is limited knowledge on the biomechanics of the spine postoperatively and a lack of models to assess the effect of PCD ex-vivo. This study aimed to develop a biomechanical model to study PCD in a repeatable and clinically relevant manner. Eleven ovine functional spinal units were dissected and tested under compression in three conditions: healthy, injured and treated. Injury was induced by a papain buffer and the treatment was conducted using PMMA cement. Each sample was scanned with micro-computed tomography (CT) and segmented for the three conditions. Similar cement volumes (in %) were injected in the ovine samples compared to volumes measured on clinical PCD CT images. Anterior and posterior disc heights decreased on average by 22.5% and 23.9% after injury. After treatment, the anterior and posterior disc height was restored on average to 98.5% and 83.6%, respectively, of their original healthy height. Compression testing showed a similar stiffness behavior between samples in the same group. A decrease of 51.5% in segment stiffness was found after injury, as expected. The following PCD treatment was found to result in a restoration of stiffness—showing only a difference of 5% in comparison to the uninjured state. The developed ex-vivo model gave an adequate representation of the clinical vacuum phenomena in terms of volume, and a repeatable mechanical response between samples. Discoplasty treatment was found to give a restoration in stiffness after injury. The data presented confirm the effectiveness of the PCD procedure in terms of restoration of axial stiffness in the spinal segment. The model can be used in the future to test more complex loading scenarios, novel materials, and different surgical techniques.

Correlation Analysis of the Characteristics of Spino-Pelvic Parameters and Health-Related Quality of Life After Long-Segment Fixation for Lenke–Silva Type 5 or 6 Degenerative Scoliosis

Purpose

To retrospectively evaluate the characteristics of spino-pelvic parameters after long-segment fixation in patients with Lenke–Silva type 5 or 6 adult degenerative scoliosis and analyze the correlation between spino-pelvic parameters and health-related quality of life (HRQL).

Methods

Thirty-two patients with degenerative scoliosis underwent long-segment posterior fixation were included. The spino-pelvic parameters were evaluated after surgery, and the HRQL scores were determined using the Scoliosis Research Society-22 (SRS-22), Oswestry Disability Index (ODI), and visual analog scale (VAS). Linear regression was used to analyze the correlation between changes in spino-pelvic parameters and improvements in HRQL.

Results

Except for PI and TK, the other parameters showed significant differences after surgery (P < 0.05). All the scores of HRQL showed significant differences after surgery. The coefficient of correlation between ΔSVA and ΔVAS is 0.687 (P = 0.003), the coefficient of correlation between ΔSVA and ΔODI is 5.828 (P < 0.001). The coefficient of correlation between ΔLL and ΔVAS is −0.089 (P < 0.001), the coefficient of correlation between ΔLL and ΔODI is −1.553 (P = 0.003). The VAS score between the SVA ≥ 4cm and SVA < 4cm group have no significant difference, but have a significant difference in ODI. In PI-LL ≥ 20°and PI-LL < 20°group, the VAS and ODI all have a significant difference between the two groups.

Conclusion

SVA and LL have an important role in maintaining the overall balance of the spine and closely related to the postoperative HRQL, better HRQL may be achieved by reducing SVA and increasing LL. Good preoperative design will help achieve the best clinical efficacy.

Biomechanical evaluation of percutaneous cement discoplasty by finite element analysis

Background

Percutaneous cement discoplasty (PCD) is a minimally invasive treatment for degenerative lumbar spine disease, but the relationship between decompression effect on the nerve root and different doses of bone cement is uncertain.

Purpose

To investigate the indirect decompression effect of cement with different doses on nerve roots and the biomechanical changes on the spine during PCD using finite element analysis (FEA).

Methods

FEA was adapted to analyze the mechanical changes in the lumbar vertebrae before and after the application of PCD.CT scan images of adult males were utilized to establish a finite element model of the lumbar vertebral body using mimics and Pro/E software. The images were divided into four models: the normal model (normal, model N), the disc degeneration model (high, model H), the intervertebral disc injected with 3 mL of bone cement (model H1), and the intervertebral disc injected with 5 mL of bone cement (model H2). All models were analyzed using the ABAQUS6.14.2 software. The normal physiological movements were simulated, and the mechanical changes in the lumbar vertebrae were observed prior to and after the cement filling application.

Results

The stress of the nerve root in model H was the largest. The nerve root stress in the model H2 was the smallest during flexion, extension, left bending, right bending, left rotation, and right rotation at 90%, 44%, 25%, 56%, 56%, and 51% of the normal benchmark, respectively. After the injection of bone cement, the nerve root stress is reduced. The greater the amount of cement, the lesser the nerve root stress. The motion was reduced in models H, H1, and H2, and there were differences between models H1 and H2. Cartilage endplate stress was less in model H2 than in model H1.

Conclusions

The nerve root stress increased after degeneration and decreased after intervertebral height recovery through cement injection, resulting in a significant indirect decompression effect.The stress of the nerve root decreased with the increase in the amount of cement injection.

Reaching the medicare allowable threshold in adult spinal deformity surgery: multicenter cost analysis comparing actual direct hospital costs versus what the government will pay

STUDY DESIGN

Retrospective multicenter cost analysis.

OBJECTIVE

To (1) determine if index episode of care (iEOC) costs of Adult Spinal Deformity (ASD) surgeries are below the Medicare Allowable (MA) threshold, and (2) identify variables that can predict iEOC cases that are below MA. Previous studies have suggested that actual direct hospital cost of Adult Spinal Deformity (ASD) surgery is higher than Medicare Allowable (MA) rates, which has become the benchmark reimbursement target for hospital accounting systems.

METHODS

From a prospective, multicenter ASD surgical database, patients undergoing long instrumented fusions (> 5 level) with cost data were identified. iEOC cost was calculated utilizing actual direct hospital cost. MA rates were calculated using hospital specific, year-appropriate CMS Inpatient Pricer Payment System. Recursive partitioning identified potentially modifiable variables that can predict iEOC cost < MA.

RESULTS

Administrative direct cost data from 210 patients were obtained from 4 of 11 centers. Ninety-five (45%) patients had iEOC cost < MA. There was significant variation across the four centers in both iEOC cost ($56,788-$78,878, p < 0.0001) and reimbursement ($40,623-$91,351, p < 0.0001) across deformity-specific DRGs (453,454,456,457). Academic centers were more likely to have iEOC costs < MA (67.2% vs 8.9%, p < 0.0001). Recursive partitioning (r² = 0.309) identified rhBMP-2 use of < 24 mg, sagittal plane deformity, a combined anterior/posterior approach, and an SF36-MCS < 39 as predictive for iEOC cost < MA. Performing an anterior/posterior approach reimburses between 14.7% and 121.1% more (2.2-fold) than posterior-only approach. This change in DRG allows iEOC cost to be more likely below the MA threshold.

CONCLUSION

There is significant institutional (private vs academic) variation in ASD reimbursement. BMP use, deformity type, approach, and baseline mental health impact ASD surgery cost being below Medicare reimbursement. ASD surgeries with anterior/posterior approaches are in DRGs that can potentially reimburse 2.2-fold the posterior-only surgery, making it more likely to fall below the MA threshold.

LEVEL OF EVIDENCE

III.

Patient outcomes after circumferential minimally invasive surgery compared with those of open correction for adult spinal deformity: initial analysis of prospectively collected data

OBJECTIVE

Circumferential minimally invasive spine surgery (cMIS) for adult scoliosis has become more advanced and powerful, but direct comparison with traditional open correction using prospectively collected data is limited. The authors performed a retrospective review of prospectively collected, multicenter adult spinal deformity data. The authors directly compared cMIS for adult scoliosis with open correction in propensity-matched cohorts using health-related quality-of-life (HRQOL) measures and surgical parameters.

METHODS

Data from a prospective, multicenter adult spinal deformity database were retrospectively reviewed. Inclusion criteria were age > 18 years, minimum 1-year follow-up, and one of the following characteristics: pelvic tilt (PT) > 25°, pelvic incidence minus lumbar lordosis (PI-LL) > 10°, Cobb angle > 20°, or sagittal vertical axis (SVA) > 5 cm. Patients were categorized as undergoing cMIS (percutaneous screws with minimally invasive anterior interbody fusion) or open correction (traditional open deformity correction). Propensity matching was used to create two equal groups and to control for age, BMI, preoperative PI-LL, pelvic incidence (PI), T1 pelvic angle (T1PA), SVA, PT, and number of posterior levels fused.

RESULTS

A total of 154 patients (77 underwent open procedures and 77 underwent cMIS) were included after matching for age, BMI, PI-LL (mean 15° vs 17°, respectively), PI (54° vs 54°), T1PA (21° vs 22°), and mean number of levels fused (6.3 vs 6). Patients who underwent three-column osteotomy were excluded. Follow-up was 1 year for all patients. Postoperative Oswestry Disability Index (ODI) (p = 0.50), Scoliosis Research Society-total (p = 0.45), and EQ-5D (p = 0.33) scores were not different between cMIS and open patients. Maximum Cobb angles were similar for open and cMIS patients at baseline (25.9° vs 26.3°, p = 0.85) and at 1 year postoperation (15.0° vs 17.5°, p = 0.17). In total, 58.3% of open patients and 64.4% of cMIS patients (p = 0.31) reached the minimal clinically important difference (MCID) in ODI at 1 year. At 1 year, no differences were observed in terms of PI-LL (p = 0.71), SVA (p = 0.46), PT (p = 0.9), or Cobb angle (p = 0.20). Open patients had greater estimated blood loss compared with cMIS patients (1.36 L vs 0.524 L, p < 0.05) and fewer levels of interbody fusion (1.87 vs 3.46, p < 0.05), but shorter operative times (356 minutes vs 452 minutes, p = 0.003). Revision surgery rates between the two cohorts were similar (p = 0.97).

CONCLUSIONS

When cMIS was compared with open adult scoliosis correction with propensity matching, HRQOL improvement, spinopelvic parameters, revision surgery rates, and proportions of patients who reached MCID were similar between cohorts. However, well-selected cMIS patients had less blood loss, comparable results, and longer operative times in comparison with open patients.

Two- and three-year outcomes of minimally invasive and hybrid correction of adult spinal deformity

OBJECTIVE

Previous studies have demonstrated the short-term radiographic and clinical benefits of circumferential minimally invasive surgery (cMIS) and hybrid (i.e., minimally invasive anterior or lateral interbody fusion with an open posterior approach) techniques to correct adult spinal deformity (ASD). However, it is not known if these benefits are maintained over longer periods of time. This study evaluated the 2- and 3-year outcomes of cMIS and hybrid correction of ASD.

METHODS

A multicenter database was retrospectively reviewed for patients undergoing cMIS or hybrid surgery for ASD. Patients were ≥ 18 years of age and had one of the following: maximum coronal Cobb angle (CC) ≥ 20°, sagittal vertical axis (SVA) > 5 cm, pelvic incidence-lumbar lordosis mismatch (PI-LL) ≥ 10°, or pelvic tilt (PT) > 20°. Radiographic parameters were evaluated at the latest follow-up. Clinical outcomes were compared at 2- and 3-year time points and adjusted for age, preoperative CC, levels operated, levels with interbody fusion, presence of L5-S1 anterior lumbar interbody fusion, and upper and lower instrumented vertebral level.

RESULTS

Overall, 197 (108 cMIS, 89 hybrid) patients were included with 187 (99 cMIS, 88 hybrid) and 111 (60 cMIS, 51 hybrid) patients evaluated at 2 and 3 years, respectively. The mean (± SD) follow-up duration for cMIS (39.0 ± 13.3 months, range 22-74 months) and hybrid correction (39.9 ± 16.8 months, range 22-94 months) were similar for both cohorts. Hybrid procedures corrected the CC greater than the cMIS technique (adjusted p = 0.022). There were no significant differences in postoperative SVA, PI-LL, PT, and sacral slope (SS). At 2 years, cMIS had lower Oswestry Disability Index (ODI) scores (adjusted p < 0.001), greater ODI change as a percentage of baseline (adjusted p = 0.006), less visual analog scale (VAS) back pain (adjusted p = 0.006), and greater VAS back pain change as a percentage of baseline (adjusted p = 0.001) compared to hybrid techniques. These differences were no longer significant at 3 years. At 3 years, but not 2 years, VAS leg pain was lower for cMIS compared to hybrid techniques (adjusted p = 0.032). Those undergoing cMIS had fewer overall complications compared to hybrid techniques (adjusted p = 0.006), but a higher odds of pseudarthrosis (adjusted p = 0.039).

CONCLUSIONS

In this review of a multicenter database for patients undergoing cMIS and hybrid surgery for ASD, hybrid procedures were associated with a greater CC improvement compared to cMIS techniques. cMIS was associated with superior ODI and back pain at 2 years, but this difference was no longer evident at 3 years. However, cMIS was associated with superior leg pain at 3 years. There were fewer complications following cMIS, with the exception of pseudarthrosis.

Single- versus Dual-Attending Surgeon Approach for Spine Deformity: A Systematic Review and Meta-Analysis

BACKGROUND

Surgical management of spine deformity is associated with significant morbidity. Recent literature has inconsistently demonstrated better outcomes after utilizing 2 attending surgeons for spine deformity.

OBJECTIVE

To conduct a systematic review and meta-analysis on studies reporting outcomes following single- vs dual-attending surgeons for spine deformity.

METHODS

MEDLINE, Embase, Web of science, and Cochrane databases were last searched on July 16, 2020. A total of 1013 records were identified excluding duplicates. After screening, 10 studies (4 cohort, 6 case series) were included in the meta-analysis. Random-effect models were used to pool the effect estimates by study design. When feasible, further subgroup analysis by deformity type was conducted.

RESULTS

A total of 953 patients were analyzed. Pooled results from propensity score-matched cohort studies revealed that the single-surgeon approach was unfavorably associated with a nonstatistically significant higher blood loss (mean difference = 421.0 mL; 95% CI: -28.2, 870.2), a statistically significant higher operative time (mean difference = 94.3 min; 95% CI: 54.9, 133), length of stay (mean difference = 0.84 d; 95% CI: 0.46, 1.22), and an increased risk of complications (Mantel-Haenszel risk ratio = 2.93; 95% CI: 1.12, 7.66). Data from pooled case series demonstrated similar results for all outcomes. Moreover, these results did not differ significantly between deformity types (adolescent idiopathic scoliosis and adult spinal deformity).

CONCLUSION

Dual-attending surgeon approach appeared to be associated with reduced operative time, shorter hospital stays, and reduced risk of complications. These findings may potentially improve outcomes in surgical treatment of spine deformity.

Cost-Effectiveness of Adult Spinal Deformity Surgery

STUDY DESIGN

Review article.

OBJECTIVE

A review of the literature evaluating the cost-effectiveness of undergoing adult spinal deformity surgery and potential avenues for reducing costs.

METHODS

A review of the current literature and synthesis of data to provide an update on the cost effectiveness of undergoing adult spinal deformity surgery.

RESULTS

Compared with nonoperative management, operative management for adult spinal deformity is associated with improved patient-reported outcomes and quality of life; however, it is associated with significant financial and resource use.

CONCLUSION

Operative management for adult spinal deformity has been shown to be effective but is associated with significant cost and resource utilization. The optimal operative treatment is highly dependent on the patients' symptomatology and is surgeon dependent. Maximizing preoperative surgical health and minimizing postoperative complications are key measures in reducing the cost and resource utilization of adult spinal deformity surgery. Future studies are needed to evaluate how to optimize the cost-effectiveness.

Is Less Really More? Economic Evaluation of Minimally Invasive Surgery

STUDY DESIGN

Review.

OBJECTIVE

A comparative overview of cost-effectiveness between minimally invasive versus and equivalent open spinal surgeries.

METHODS

A literature search using PubMed was performed to identify articles of interest. To maximize the capture of studies in our initial search, we combined variants of the terms "cost," "minimally invasive," "spine," "spinal fusion," "decompression" as either keywords or MeSH terms. PearlDiver database was queried for open and minimally invasive surgery (MIS; endoscopic or percutaneous) reimbursements between Q3 2015 and Q2 2018.

RESULTS

In general, MIS techniques appeared to decrease blood loss, shorten hospital lengths of stay, mitigate complications, decrease perioperative pain, and enable quicker return to daily activities when compared to equivalent open surgical techniques. With regard to cost, primarily as a result of these latter benefits, MIS was associated with lower costs of care when compared to equivalent open techniques. However, cost reporting was sparse, and relevant methodology was inconsistent throughout the spine literature. Within the PearlDiver data sets, MIS approaches had lower reimbursements than open approaches for both lumbar posterior fusion and discectomy.

CONCLUSIONS

Current data suggests that overall cost-savings may be incurred with use of MIS techniques. However, data reporting on costs lacks in uniformity, making it difficult to formulate any firm conclusions regarding any incremental improvements in cost-effectiveness that may be incurred when utilizing MIS techniques when compared to equivalent open techniques.

Classifying Complications: Assessing Adult Spinal Deformity 2-Year Surgical Outcomes

STUDY DESIGN

Retrospective review of prospective database.

OBJECTIVE

Complication rates for adult spinal deformity (ASD) surgery vary widely because there is no accepted system for categorization. Our objective was to identify the impact of complication occurrence, minor-major complication, and Clavien-Dindo complication classification (Cc) on clinical variables and patient-reported outcomes.

METHODS

Complications in surgical ASD patients with complete baseline and 2-year data were considered intraoperatively, perioperatively (<6 weeks), and postoperatively (>6 weeks). Primary outcome measures were complication timing and severity according to 3 scales: complication presence (yes/no), minor-major, and Cc score. Secondary outcomes were surgical outcomes (estimated blood loss [EBL], length of stay [LOS], reoperation) and health-related quality of life (HRQL) scores. Univariate analyses determined complication presence, type, and Cc grade impact on operative variables and on HRQL scores.

RESULTS

Of 167 patients, 30.5% (n = 51) had intraoperative, 48.5% (n = 81) had perioperative, and 58.7% (n = 98) had postoperative complications. Major intraoperative complications were associated with increased EBL (P < .001) and LOS (P = .0092). Postoperative complication presence and major postoperative complication were associated with reoperation (P < .001). At 2 years, major perioperative complications were associated with worse ODI, SF-36, and SRS activity and appearance scores (P < .02). Increasing perioperative Cc score and postoperative complication presence were the best predictors of worse HRQL outcomes (P < .05).

CONCLUSION

The Cc Scale was most useful in predicting changes in patient outcomes; at 2 years, patients with raised perioperative Cc scores and postoperative complications saw reduced HRQL improvement. Intraoperative and perioperative complications were associated with worse short-term surgical and inpatient outcomes.

[Efficacy and safety of tranexamic acid sequential rivaroxaban on blood loss in elderly patients during lumbar interbody fusion]

Objective

To investigate the effect and safety of tranexamic acid sequential rivaroxaban on perioperative blood loss and preventing thrombosis for elderly patients during lumbar interbody fusion (LIF) with a prospective randomized controlled study.

Methods

Between April and October 2019, the elderly patients with lumbar degenerative diseases requiring LIF were included in the study, among which were 80 patients met the selection criteria. According to the antifibrinolysis and anticoagulation protocols, they were randomly divided into a tranexamic acid sequential rivaroxaban group (trial group) and a simple rivaroxaban group (control group) on average. Finally, 69 patients (35 in the trial group and 34 in the control group) were included for comparison. There was no significant difference in general data ( P>0.05) such as gender, age, body mass index, disease duration, diseased segment, type of disease, and preoperative hemoglobin between the two groups. The operation time, intraoperative blood loss, drainage within 3 days after operation, perioperative total blood loss, and proportion of blood transfusion patients were compared between the two groups, as well as postoperative venous thrombosis of lower extremities, pulmonary embolism, and bleeding-related complications.

Results

The operations of the two groups completed successfully, and there was no significant difference in the operation time ( P>0.05); the intraoperative blood loss, drainage within 3 days after operation, and perioperative total blood loss in the trial group were significantly lower than those in the control group ( P<0.05). The proportion of blood transfusion patients in the trial group was 25.71% (9/35), which was significantly lower than that in the control group [52.94% (18/34)] ( χ ²=5.368, P=0.021). Postoperative incision bleeding occurred in 4 cases of the trial group and 3 cases of the control group, and there was no significant difference in bleeding-related complications between the two groups ( P=1.000). There was 1 case of venous thrombosis of the lower extremities in each group after operation, and there was no significant difference in the incidence between the two groups ( P=1.000). Besides, no pulmonary embolism occurred in the two groups.

Conclusion

Perioperative use of tranexamic acid sequential rivaroxaban in elderly LIF patients can effectively reduce the amount of blood loss and the proportion of blood transfusion patients without increasing the risk of postoperative thrombosis.

Percutaneous Cement Discoplasty for the Treatment of Advanced Degenerative Disc Conditions: A Case Series Analysis

STUDY DESIGN

Retrospective analysis. Level of evidence III.

OBJECTIVES

To describe the results after a minimum 1-year follow-up in patients treated with percutaneous discoplasty (PD), a minimally invasive technique to treat low back pain in elderly patients with advanced degenerative disc disease. The procedure consists in improving stability by injecting bone cement in a severely degenerated pneumodisc. There are few reports in the literature about this technique.

METHODS

Fifty-four patients with advanced disc disease with/without degenerative scoliosis treated with PD with at least 1 year follow-up were studied, variables included clinical (visual analogue scale [VAS] and Owestry Disability Index [ODI]) and radiological parameters (lumbar lordosis and Cobb angle), as well as hospital length of stay and complications.

RESULTS

At 1-year postoperation, significant pain reduction (VAS: preoperative 7.8 ± 0.90; postoperative 4.4 ± 2.18) and improvement in the ODI (preoperative 62 ± 7.12; postoperative 36.2 ± 15.47) were observed with partial correction of radiological parameters (5° mean increase in lumbar lordosis and decrease in Cobb angle). Mean surgical time was 38 minutes, and the mean length of hospital stay was 1.2 days.

CONCLUSION

PD, currently not a very well-known technique, appears to be-at least in the short-term follow-up-an effective treatment option in selected cases with low back pain due to advanced degenerative disc disease.

Minimally invasive versus open surgery for the correction of adult degenerative scoliosis: a systematic review

While open surgery has been the primary surgical approach for adult degenerative scoliosis, minimally invasive surgery (MIS) represents an alternative option and appears to be associated with reduced morbidity. Given the lack of consensus, we aimed to conduct a systematic review on available literature comparing MIS versus open surgery for adult degenerative scoliosis. PubMed, Embase, and Cochrane databases were searched through December 16, 2019, for studies that compared both MIS and open surgery in patients with degenerative scoliosis. Four cohort studies reporting on 350 patients met the inclusion criteria. In two studies, patients undergoing open surgery were younger and had more severe disease at baseline as compared with MIS. Patients who underwent MIS had less blood loss, shorter length of stay, and a reduced rate of complications and infections. Both MIS and open surgery resulted in a significant change in pain and disability scores and both approaches provided significant correction of deformity in all studies, although open surgery was associated with a greater change in pelvic incidence-lumbar lordosis mismatch (PI-LL) and sagittal vertical axis (SVA) in two and three studies, respectively. In patients with adult degenerative scoliosis undergoing surgery, both MIS and open approaches appeared to offer comparable improvements in pain and function. However, MIS was associated with better safety outcomes, while open surgery provided greater correction of spinal deformity. Further studies are needed to identify specific subset of patients who may benefit from one approach versus the other.

SURGERY FOR ADULT SPINAL SCOLIOSIS: DO THE BENEFITS OUTWEIGH THE RISKS?

ABSTRACT Around 6% of the elderly population over 65 years of age are affected by adult spinal deformity (ASD). The increasing prevalence of ASD with aging has prompted discussion regarding the use of various techniques for its treatment, such as surgery and conservative treatment. The objective of this study is to investigate whether surgical treatment demonstrates significant benefits as compared to conservative treatment. A literature review was conducted, focusing on the most relevant papers on the topic published in the last five years. Surgical treatment, which costs an average of US$ 99,114 per procedure, enables almost instant improvement of the pain and disability of ASD. The rate of perioperative complications in ASD is approximately 7.5%, and the average improvement in back pain is 6.2 times higher in the surgical approach than in conservative treatment. In addition, the use of modern operative techniques, such as minimally invasive surgery (MIS), reduces the complications and greatly improves patients’ quality of life, compared to open surgery. Therefore, the expected benefits of surgical treatment meets the patient’s expectations by eliminating the pain caused by ASD. Although surgical treatment has a higher cost and a greater risk of complications, the use of minimally invasive techniques give the ASD patient a better quality of life. Level of evidence III; Non-Systematic Review.

Economic Value in Minimally Invasive Spine Surgery

PURPOSE OF REVIEW

The field of spine surgery remains a unique target in the transition to value-based care. While spine surgery has benefited from new medical technologies, including minimally invasive surgery (MIS), these technologies may be a key driver in rising US healthcare costs. As such, MIS needs to clear an economic value threshold through a rigorous evaluation of the outcomes they provide and costs they incur. In this article, we review recent MIS surgery literature from the perspective of economic value.

RECENT FINDINGS

Many studies report modest all-in cost savings and direct procedural cost equivalence for minimally invasive approaches relative to open surgeries. In terms of quality, studies found lower blood loss, length of stay, and infectious complications with MIS surgery but evidence on QALYs was mixed. In the past 5 years, there has been increasing research interest in defining economic value in MIS surgery. However, a significant amount of heterogeneity in research quality and methodology persists. Therefore, MIS surgery has the potential to be of high economic value, though this is not yet definitive. Future research should continue to focus on high-quality cost-effectiveness studies with clear methodologies to further elucidate economic value in MIS surgery.

Predicting Clinical Outcomes Following Surgical Correction of Adult Spinal Deformity

BACKGROUND

Deformity reconstruction surgery has been shown to improve quality of life (QOL) in cases of adult spinal deformity (ASD) but is associated with significant morbidity.

OBJECTIVE

To create a preoperative predictive nomogram to help risk-stratify patients and determine which would likely benefit from corrective surgery for ASD as measured by patient-reported health-related quality of life (HRQoL).

METHODS

All patients aged 25-yr and older with radiographic evidence of ASD and QOL data that underwent thoracolumbar fusion between 2008 and 2014 were identified. Demographic and clinical parameters were obtained. The EuroQol 5 dimensions questionnaire (EQ-5D) was used to measure HRQoL preoperatively and at 12-mo postoperative follow-up. Logistic regression of preoperative variables was used to create the prognostic nomogram.

RESULTS

Our sample included data from 191 patients. Fifty-one percent of patients experienced clinically relevant postoperative improvement in HRQoL. Seven variables were included in the final model: preoperative EQ-5D score, sex, preoperative diagnosis (degenerative, idiopathic, or iatrogenic), previous spinal surgical history, obesity, and a sex-by-obesity interaction term. Preoperative EQ-5D score independently predicted the outcome. Sex interacted with obesity: obese men were at disproportionately higher odds of improving than nonobese men, but obesity did not affect odds of the outcome among women. Model discrimination was good, with an optimism-adjusted c-statistic of 0.739.

CONCLUSION

The predictive nomogram that we developed using these data can improve preoperative risk counseling and patient selection for deformity correction surgery.

Opioid Dependence and Health Care Utilization After Decompression and Fusion in Patients With Adult Degenerative Scoliosis

STUDY DESIGN

Retrospective study.

OBJECTIVE

To identify factors associated with opioid dependence after surgery for adult degenerative scoliosis (ADSc).

SUMMARY OF BACKGROUND DATA

Opioid epidemic is of prodigious concern throughout the United States.

METHODS

Data was extracted using national MarketScan database (2000-2016). Opioid dependence was defined as continued opioid use or >10 opioid prescriptions for 1 year either before or 3 to 15 months after the procedure. Patients were segregated into four groups based on opioid dependence before and postsurgery: NDND (before nondependent who remain non-dependent), NDD (before nondependent who become dependent), DND (before dependent who become non-dependent) and DD (before dependent who remain dependent). Outcomes were discharge disposition, length of stay, complications, and healthcare resource utilization.

RESULTS

Approximately, 35.82% (n = 268) of patients were identified to have opioid dependence before surgery and 28.34% (n = 212) were identified to have opioid dependence after surgery for ADSc. After surgical fusion for ADSc, patients were twice likely to become opioid independent than they were to become dependent (13.77% vs. 6.28%, OR: 2.191, 95% CI: 21.552-3.094; P < 0.0001). Before opioid dependence (RR: 14.841; 95% CI: 9.867, 22.323; P < 0.0001) was identified as a significant predictor of opioid dependence after surgery for ADSc. In our study, 57.9%, 6.28%, 13.77%, and 22.06% of patients were in groups NDND, NDD, DND, and DD respectively. DD and NDD were likely to incur 3.03 and 2.28 times respectively the overall costs compared with patients' ingroup NDND (P < 0.0001), at 3 to 15 months postsurgery (median $21648 for NDD; $40,975 for DD; and $ 13571 for NDND groups).

CONCLUSION

Surgery for ADSc was not associated with increased likelihood of opioid dependence, especially in opioid naïve patients. Patients on regular opiate treatment before surgery were likely to remain on opiates after surgery. Patients who continued to be opioid dependent or become dependent after surgery incur significantly higher healthcare utilization at 3 and 3 to 15 months.

LEVEL OF EVIDENCE

4.

Evidence Based Medicine Review of Posterior Thoracolumbar Minimally Invasive Technology

Background

Evaluate the current evidence in meta-analyses on posterior thoracolumbar minimally invasive surgery techniques and outcomes for degenerative conditions.

Methods

A systematic review of the literature from 1950 to 2015.

Results

The review of the literature yielded 34 meta-analysis studies evaluating posterior thoracolumbar minimally invasive techniques and outcomes for degenerative conditions. There were 11 studies included which investigated minimally invasive surgery (MIS) versus open posterior lumbar decompressions. There were 14 studies included which investigated MIS versus open posterior lumbar interbody fusions. Finally, there were 9 studies focused on navigation techniques and radiation safety within MIS procedures.

Conclusions

There are 34 meta-analysis studies evaluating minimally invasive to open thoracolumbar surgery for degenerative disease. The studies show a trend toward decreased estimated blood loss, decreased length of stay, decreased complications, similar fusion rates, improved accuracy, and decreased radiation when minimally invasive techniques are used.

The impact of age on surgical goals for spinopelvic alignment in minimally invasive surgery for adult spinal deformity

OBJECTIVE

Achieving appropriate spinopelvic alignment in deformity surgery has been correlated with improvement in pain and disability. Minimally invasive surgery (MIS) techniques have been used to treat adult spinal deformity (ASD); however, there is concern for inadequate sagittal plane correction. Because age can influence the degree of sagittal correction required, the purpose of this study was to analyze whether obtaining optimal spinopelvic alignment is required in the elderly to obtain clinical improvement.

METHODS

A multicenter database of ASD patients was queried. Inclusion criteria were age ≥ 18 years; an MIS component as part of the index procedure; at least one of the following: pelvic tilt (PT) > 20°, sagittal vertical axis (SVA) > 50 mm, pelvic incidence to lumbar lordosis (PI-LL) mismatch > 10°, or coronal curve > 20°; and minimum follow-up of 2 years. Patients were stratified into younger (< 65 years) and older (≥ 65 years) cohorts. Within each cohort, patients were categorized into aligned (AL) or mal-aligned (MAL) subgroups based on postoperative radiographic measurements. Mal-alignment was defined as a PI-LL > 10° or SVA > 50 mm. Pre- and postoperative radiographic and clinical outcomes were compared.

RESULTS

Of the 185 patients, 107 were in the younger cohort and 78 in the older cohort. Based on postoperative radiographs, 36 (33.6%) of the younger patients were in the AL subgroup and 71 (66.4%) were in the MAL subgroup. The older patients were divided into 2 subgroups based on alignment; there were 26 (33.3%) patients in the AL and 52 (66.7%) in the MAL subgroups. Overall, patients within both younger and older cohorts significantly improved with regard to postoperative visual analog scale (VAS) scores for back and leg pain and Oswestry Disability Index (ODI) scores. In the younger cohort, there were no significant differences in postoperative VAS back and leg pain scores between the AL and MAL subgroups. However, the postoperative ODI score of 37.9 in the MAL subgroup was significantly worse than the ODI score of 28.5 in the AL subgroup (p = 0.019). In the older cohort, there were no significant differences in postoperative VAS back and leg pain score or ODI between the AL and MAL subgroups.

CONCLUSIONS

MIS techniques did not achieve optimal spinopelvic alignment in most cases. However, age appears to impact the degree of sagittal correction required. In older patients, optimal spinopelvic alignment thresholds did not need to be achieved to obtain similar symptomatic improvement. Conversely, in younger patients stricter adherence to optimal spinopelvic alignment thresholds may be needed.

https://thejns.org/doi/abs/10.3171/2018.4.SPINE171153

Does Day of Surgery Affect Hospital Length of Stay and Charges Following Minimally Invasive Transforaminal Lumbar Interbody Fusion?

STUDY DESIGN

Retrospective Cohort.

OBJECTIVE

To determine if an association exists between surgery day and length of stay or hospital costs after minimally invasive transforaminal lumbar interbody fusion (MIS TLIF).

SUMMARYOF BACKGROUND DATA

Length of inpatient stay after orthopedic procedures has been identified as a primary cost driver, and previous research has focused on determining risk factors for prolonged length of stay. In the arthroplasty literature, surgery performed later in the week has been identified as a predictor of increased length of stay. However, no such investigation has been performed for MIS TLIF.

MATERIALS AND METHODS

A surgical registry of patients undergoing MIS TLIF between 2008 and 2016 was retrospectively reviewed. Patients were grouped based on day of surgery, with groups including early surgery and late surgery. Day of surgery group was tested for an association with demographics and perioperative variables using the student t test or χ analysis. Day of surgery group was then tested for an association with direct hospital costs using multivariate linear regression.

RESULTS

In total, 438 patients were analyzed. In total, 51.8% were in the early surgery group, and 48.2% were in the late surgery group. There were no differences in demographics between groups. There were no differences between groups with regard to operative time, intraoperative blood loss, length of stay, or discharge day. Finally, there were no differences in total hospital charges between early and late surgery groups (P=0.247).

CONCLUSIONS

The specific day on which a MIS TLIF procedure occurs is not associated with differences in length of inpatient stay or total hospital costs. This suggests that the postoperative course after MIS TLIF procedures is not affected by the differences in hospital staffing that occurs on the weekend compared with weekdays.

Assessment of cost drivers and cost variation for lumbar interbody fusion procedures using the Value Driven Outcomes database

OBJECTIVE

Efforts to examine the value of care—combining both costs and quality—are gaining importance in the current health care climate. This thrust is particularly evident in treating common spinal disease where both incidences and costs are generally high and practice patterns are variable. It is often challenging to obtain direct surgical costs for these analyses, which hinders the understanding of cost drivers and cost variation. Using a novel tool, the authors sought to understand the costs of posterior lumbar arthrodesis with interbody devices.

METHODS

The Value Driven Outcomes (VDO) database at the University of Utah was used to evaluate the care of patients who underwent open or minimally invasive surgery (MIS), 1- and 2-level lumbar spine fusion (Current Procedural Terminology code 22263). Patients treated from January 2012 through June 2017 were included.

RESULTS

A total of 276 patients (mean age 58.9 ± 12.4 years) were identified; 46.7% of patients were men. Most patients (82.2%) underwent 1-level fusion. Thirteen patients (4.7%) had major complications and 11 (4.1%) had minor complications. MIS (β = 0.16, p = 0.002), length of stay (β = 0.47, p = 0.0001), and number of operated levels (β = 0.37, p = 0.0001) predicted costs in a multivariable analysis. Supplies and implants (55%) and facility cost (36%) accounted for most of the expenditure. Other costs included pharmacy (7%), laboratory (1%), and imaging (1%).

CONCLUSIONS

These results provide direct cost accounting for lumbar fusion procedures using the VDO database. Efforts to improve the value of lumbar surgery should focus on high cost areas, i.e., facility and supplies/implant.

Minimally Invasive Spinal Surgery for Adult Spinal Deformity

The purpose of this review is to present the current techniques and outcomes of adult spine deformity (ASD) surgery using the minimally invasive spine surgery (MISS) approach. We performed a systemic search of PubMed for literature published through January 2018 with the following terms: "minimally invasive spine surgery," "adult spinal deformity," and "degenerative scoliosis." Of the 138 items that were found through this search, 57 English-language articles were selected for full-text review. According to the severity of the deformity and the symptoms, various types of MISS have been utilized, such as MISS decompression, circumferential MISS, and hybrid surgery. With proper indications, the MISS approach achieved satisfactory clinical and radiological outcomes for ASD, with reduced complication rates. Future studies should aim to define clear indications for the application of various surgical options.

Percutaneous cement discoplasty for the treatment of advanced degenerative disk disease in elderly patients

PURPOSE

The authors describe a percutaneous technique to treat advanced degenerative disk disease in elderly patients.

METHOD

A step-by-step technical description based on our experience in selected cases.

RESULT

Postoperative imaging results are presented as well as indications and recommendations.

CONCLUSION

Percutaneous discoplasty can result as an alternative minimal invasive strategy for the treatment of advanced degenerative disk disease.

Comparison of lateral lumbar interbody fusion (LLIF) with open versus percutaneous screw fixation for adult degenerative scoliosis

Study design

Retrospective Review.

Objectives

Compare clinical outcomes and radiographic correction of adult degenerative scoliosis (ADS) patients treated with lateral lumbar interbody fusion (LLIF), combined either with percutaneous (no laminectomy) versus open laminectomy/pedicle screw instrumentation.

Methods

Twenty-two ADS patients undergoing combined LLIF and posterior instrumentation were divided into two groups: thirteen patients underwent LLIF with open laminectomy and posterior pedicle instrumentation (Group-1, six revision); nine patients underwent LLIF with percutaneous pedicle instrumentation (no decompression) (Group-2). Radiographs, CT/MRI, peri-operative complications, VAS, SF-12, and ODI were measured.

Results

Average follow up was 22 months. In Group-1 and Group-2, respectively: Mean coronal Cobb angle corrected 12.6° and 5.8°; Mean regional lumbar lordosis improved 11.1° and 3.8°; Pelvic incidence minus lumbar lordosis mismatch corrected to within +/-9° in 46% and 0% of patients; Mean VAS improved from 5.4 to 2.8 and 6.3 to 1; Mean ODI improved 19% and 22%. Improvements were found in SF-12 PCS and MCS scores.

Conclusions

Both open and percutaneous posterior techniques following LLIF significantly improved clinical outcomes. Open procedures resulted in significantly better radiographic improvements but also higher complication rates. LLIF with percutaneous posterior fixation, without decompression, should be considered part of the algorithm in select ADS patients with remaining compensatory mechanisms and understanding that greater degrees of correction may require an open, more extensive approach.

Cost-Effectiveness in Adult Spinal Deformity Surgery

The complexity and heterogeneity of adult spinal deformity (ASD) creates significant difficulties in performing high-quality, complete economic analyses. For the same reasons, however, such studies are immensely valuable to clinicians and health policy experts. There has been a paradigm shift towards value-based healthcare provision and as such, there is an increasing focus on demonstrating not just the value ASD surgery, but the provision of care at large. Health-related quality of life measures are an important tool for assessing value of an intervention and its effect on a quality-adjusted life year (QALY). Currently, there are no definitive criteria in regard to assigning the appropriate value to a QALY. A general accepted threshold discussed in literature is $100 000 per QALY gained. However, this figure may be variable across populations, and may not necessarily be applicable in today's economy, or in all healthcare economies. Fundamentally, an effective treatment method may be associated with a high upfront cost, however, if durable, will be cost-effective over time.

The emphasis on cost-effectiveness and cost-utility analysis in the field of adult spine deformity is relatively recent; therefore, there is a limited amount of data on cost-effectiveness analyses. Continued efforts with emphasis on value-based outcomes are needed with long-term follow-up studies.

Degenerative Scoliosis

PURPOSE OF REVIEW

The purpose of this review is to provide an updated review of adult degenerative scoliosis (ADS). Epidemiology, classification, pathophysiology, and natural history are discussed along with a summary of commonly used outcome measures. Operative vs non-operative outcomes and new surgical techniques are discussed.

RECENT FINDINGS

The SRS-Schwab classification (2012) combines clinical and radiographic evaluation including overall global alignment. Current evidence regarding risk factors and efficacy of non-surgical modalities are discussed. Recent studies have reported surgical management to provide superior outcomes to non-operative modalities. New surgical techniques provide promising early data in regard to decreasing perioperative morbidity. ADS is a potentially debilitating condition that occurs with asymmetric spinal degeneration. This can produce global sagittal malalignment and central and foraminal stenosis and can lead to significant impairment often necessitating surgery. The surgeon must be aware of the perioperative risks in this population and implement appropriate age-specific alignment goals to achieve the best outcome for patients.

Early Ambulation Decreases Length of Hospital Stay, Perioperative Complications and Improves Functional Outcomes in Elderly Patients Undergoing Surgery for Correction of Adult Degenerative Scoliosis

STUDY DESIGN

Ambispective cohort review.

OBJECTIVE

To examine the effects of early mobilization on patient outcomes, complications profile, and 30-day readmission rates.

SUMMARY OF BACKGROUND DATA

Prolonged immobilization after surgery can result in functional decline and an increased risk of hospital-associated complications.

METHODS

We conducted an ambispective study of 125 elderly patients (>65 years) undergoing elective spinal surgery for correction of adult degenerative scoliosis. We identified all unplanned readmissions within 30 days of discharge. Unplanned readmissions were defined to have occurred as a result of either a surgical or a nonsurgical complication. "Days of immobility" was defined as the number of days until a patient moved out of bed beyond a chair. Patients in the top and bottom quartiles were dichotomized into "early ambulators" and "late ambulators", respectively. Early ambulators were ambulatory within 24 hours of surgery, whereas late ambulators were ambulatory at a minimum of 48 hours after surgery. Complication rates, duration of hospital stay, and 30-day readmission rates were compared between early ambulators and late ambulators.

RESULTS

Baseline characteristics were similar between both cohorts. Compared with patients with a longer duration of immobility (i.e., late ambulators), the prevalence of at least one perioperative complication was significantly lower in the early ambulators cohort (30% vs. 54%, P = 0.06). The length of inhospital stay was 34% shorter in the early ambulators cohort (5.33 days vs. 8.11 days, P = 0.01). Functional independence was superior in the early ambulators cohort, with the majority of patients discharged directly home after surgery compared with late ambulators (71.2% vs. 22.0%, P = 0.01).

CONCLUSION

Early ambulation after surgery significantly reduces the incidence of perioperative complications, shortens duration of inhospital stay, and contributes to improved perioperative functional status in elderly patients. Even a delay of 24 hours to ambulation is associated with higher complication rates and inferior functional outcomes.

LEVEL OF EVIDENCE

3.

Mini-open spinal column shortening for the treatment of adult tethered cord syndrome

Tethered cord syndrome (TCS) is a challenging entity characterized by adhesions at the caudal spinal cord that prevent upward movement during growth and result in stretching of the cord with a concomitant constellation of neurologic symptoms. Although growth in height stops in adulthood, some patients still develop progressive symptoms; many underwent detethering as a child or adolescent, resulting in significant scar tissue and re-tethering. Recent strategies have focused on spinal column shortening to reduce tension on the spinal cord without exposing the previous de-tethering site. Mini-open and minimally invasive approaches avoid the large dissection and exposure associated with traditional approaches and are associated with reduced blood loss, shorter hospital stay, and similar outcomes when compared to conventional open approaches. We describe a technique for mini-open spinal column shortening. Using intraoperative navigation pedicle screws were placed at T10, T11, L1, and L2. A mini-open 3-column "egg shell" decancellation osteotomy of T12 was performed through a transpedicular approach with preservation of the superior and inferior endplates. This procedure was performed on a 28year old male with recurrent TCS and neurogenic bladder. Postoperative imaging showed a reduction in spinal column length of 1.5cm and evidence of decreased tension on the spinal cord. At last follow-up he was recovering well with improved urinary function. Spinal column shortening for adult TCS can be safely achieved through a mini-open approach. Future studies should compare the efficacy of this technique to both traditional de-tethering and open spinal column shortening.

Anatomical differences in patients with lumbosacral transitional vertebrae and implications for minimally invasive spine surgery

OBJECTIVE

The objective of this study was to investigate the neurovascular and anatomical differences in patients with lumbosacral transitional vertebrae (LSTV) and the associated risk of neurovascular injury in minimally invasive spine surgery.

METHODS

The authors performed a retrospective study of CT and MR images of the lumbar spine obtained at their institution between 2010 and 2014. The following characteristics were evaluated: level of the iliac crest in relation to the L4–5 disc space, union level of the iliac veins and arteries in relation to the L4–5 disc space, distribution of the iliac veins and inferior vena cava according to the different Moro zones (A, I, II, III, IV, P) at the L4–5 disc space, and the location of the psoas muscle at the L4–5 disc space. The findings were compared with findings on images obtained in 28 age- and sex-matched patients without LSTV who underwent imaging studies during the same time period.

RESULTS

Twenty-eight patients (12 male, 16 female) with LSTV and the required imaging studies were identified; 28 age- and sex-matched patients who had undergone CT and MRI studies of the thoracic and lumbar spine imaging but did not have LSTV were selected for comparison (control group). The mean ages of the patients in the LSTV group and the control group were 52 and 49 years, respectively. The iliac crest was located at a mean distance of 12 mm above the L4–5 disc space in the LSTV group and 4 mm below the L4–5 disc space in the controls. The iliac vein union was located at a mean distance of 8 mm above the L4–5 disc space in the LSTV group and 2.7 mm below the L4–5 disc space in the controls. The iliac artery bifurcation was located at a mean distance of 23 mm above the L4–5 disc space in the LSTV group and 11 mm below the L4–5 disc space in controls. In patients with LSTV, the distribution of iliac vein locations was as follows: Zone A, 7.1%; Zone I only, 78.6%; Zone I encroaching into Zone II, 7.1%; and Zone II only, 7.1%. In the control group, the distribution was as follows: Zone A only, 17.9%; Zone A encroaching into Zone I, 75%; and Zone I only, 7.1%. There were no iliac vessels in Zone II in the control group. The psoas muscle was found to be rising away laterally and anteriorly from the vertebral body more often in patients with LSTV, resulting in the iliac veins being found in the “safe zone” only 14% of the time, greatly increasing the risk of vascular injury.

CONCLUSIONS

In patients with LSTV, the iliac crest is more likely to be above the L4–5 disc space, which increases the technical challenges of a lateral approach. The location of the psoas muscle rising away laterally and ventrally in patients with LSTV compared with controls and with the union of the iliac veins occurring more often above the L4–5 disc space increases the risk for iatrogenic vascular injury at the L4–5 level in this patient population.

Lateral interbody fusion combined with open posterior surgery for adult spinal deformity

OBJECTIVE Lateral interbody fusion (LIF) with percutaneous screw fixation can treat adult spinal deformity (ASD) in the coronal plane, but sagittal correction is limited. The authors combined LIF with open posterior (OP) surgery using facet osteotomies and a rod-cantilever technique to enhance lumbar lordosis (LL). It is unclear how this hybrid strategy compares to OP surgery alone. The goal of this study was to evaluate the combination of LIF and OP surgery (LIF+OP) for ASD. METHODS All thoracolumbar ASD cases from 2009 to 2014 were reviewed. Patients with < 6 months follow-up, prior fusion, severe sagittal imbalance (sagittal vertical axis > 200 mm or pelvic incidence-LL > 40°), and those undergoing anterior lumbar interbody fusion were excluded. Deformity correction, complications, and outcomes were compared between LIF+OP and OP-only surgery patients. RESULTS LIF+OP (n = 32) and OP-only patients (n = 60) had similar baseline features and posterior fusion levels. On average, 3.8 LIFs were performed. Patients who underwent LIF+OP had less blood loss (1129 vs 1833 ml, p = 0.016) and lower durotomy rates (0% vs 23%, p = 0.002). Patients in the LIF+OP group required less ICU care (0.7 vs 2.8 days, p < 0.001) and inpatient rehabilitation (63% vs 87%, p = 0.015). The incidence of new leg pain, numbness, or weakness was similar between groups (28% vs 22%, p = 0.609). All leg symptoms resolved within 6 months, except in 1 OP-only patient. Follow-up duration was similar (28 vs 25 months, p = 0.462). LIF+OP patients had significantly less pseudarthrosis (6% vs 27%, p = 0.026) and greater improvement in visual analog scale back pain (mean decrease 4.0 vs 1.9, p = 0.046) and Oswestry Disability Index (mean decrease 21 vs 12, p = 0.035) scores. Lumbar coronal correction was greater with LIF+OP surgery (mean [± SD] 22° ± 13° vs 14° ± 13°, p = 0.010). LL restoration was 22° ± 13°, intermediately between OP-only with facet osteotomies (11° ± 7°, p < 0.001) and pedicle subtraction osteotomy (29° ± 10°, p = 0.045). CONCLUSIONS LIF+OP is an effective strategy for ASD of moderate severity. Compared with the authors' OP-only operations, LIF+OP was associated with faster recovery, fewer complications, and greater relief of pain and disability.