Anterior Aesthetic Rib Cage Remodeling With Osteosynthesis

Abstract

Background:

Body contouring is an increasingly common trend in aesthetic plastic surgery. In the pursuit of ideal body proportions, anterior thoracic cage deformities, especially lower rib cartilage prominence have emerged as a frequent source of dissatisfaction. To address this concern, the anterior aesthetic rib cage remodeling with osteosynthesis (ARCO) technique was developed as an innovative method to reshape the anterior rib cage.

Methods:

A retrospective study was conducted in Colombia on patients who underwent the ARCO procedure. Preoperative and postoperative rib cage perimeter measurements were recorded. Spirometry was performed preoperatively and during long-term follow-up to assess potential changes in respiratory volumes. Intraoperative peak pressure and pulmonary compliance values were monitored to evaluate procedural safety. Postoperative satisfaction was assessed using the BODY-Q questionnaire, and all complications were documented.

Results:

A total of 34 patients were included, with a mean age of 34 years. A significant reduction in the inferior rib cage perimeter at the level of the eighth rib was observed (Mann-Whitney U =190, P < 0.001), with a mean decrease of 2 cm. Intraoperative peak inspiratory pressure and pulmonary compliance remained stable across all procedural stages. Spirometric analyses revealed no restrictive changes in respiratory volumes.

Conclusions:

The ARCO technique offers an effective approach for reducing chest circumference and enhancing the aesthetic contour of the anterior rib margin while achieving high patient satisfaction. It involves a controlled greenstick fracture followed by osteosynthesis to create a stable and natural rib curvature, reducing the risk of malunion and eliminating the need for postoperative corsets.

Takeaways

Question: Is it possible to modify the anterior rib cage border to get a better aesthetic outcome in body contouring procedures?

Findings: Anterior aesthetic rib cage remodeling with osteosynthesis is a novel technique that effectively reduces chest perimeter at the eighth rib, enhancing the aesthetic appeal of the anterior rib margin and achieving high patient satisfaction.

Meaning: Anterior aesthetic rib cage remodeling with osteosynthesis ensures proper rib curvature, preventing malunion-related complications and eliminating the need for postoperative corsets. The intervention has proven to be safe for patients, as intra- and postoperative respiratory reference values did not show any statistically significant alterations.

INTRODUCTION

Body contouring has become one of the most prominent trends in contemporary aesthetic plastic surgery, encompassing procedures designed to fulfill patients’ aesthetic expectations, such as achieving smaller hips, a defined abdomen, and enhanced breast or buttock volume.¹ According to the 2022 International Society of Aesthetic Plastic Surgery Global Survey, body contouring procedures accounted for 4 of the 5 most frequently performed aesthetic procedures worldwide: liposuction (first), followed by breast augmentation (second), abdominoplasty (fourth), and mastopexy (fifth). These procedures also demonstrated a consistent year-to-year increase, ranging between 19% and 29% compared with that in 2021.²

During recent years, body-contouring techniques have evolved substantially, with innovative approaches extending to posterior rib reshaping. Early methods involved partial resection of ribs 11 and 12 to achieve a narrower waist circumference.^3,4 However, due to the associated complications and long-term sequelae, these procedures were progressively abandoned. Subsequently, safer and more conservative alternatives emerged, favoring the preservation of ribs 11 and 12 while performing controlled greenstick fractures to achieve the desired angulation and waist reduction.⁵

Despite these advances, the pursuit of an ideal body silhouette has also revealed previously underrecognized anterior thoracic deformities, such as dysmorphia or prominence of the anteroinferior costal cartilages, which often contribute to both pre- and postoperative dissatisfaction. Drawing from the same rib osteotomy with osteosynthesis stabilization (RIBOSS) principle, which uses plate fixation following controlled rib angulation,⁶ the anterior aesthetic rib cage remodeling with osteosynthesis (ARCO) technique was conceived. ARCO is a novel surgical intervention for anterior rib reshaping that uses osteosynthesis fixation to remodel ribs 6, 7, and 8 at approximately 40 degrees, correcting deformities or prominences of the anteroinferior rib cage. This adjustment enhances the aesthetic harmony of the thoracic contour and increases overall patient satisfaction following body contouring surgery. Importantly, the ARCO procedure fulfills the fundamental criteria for surgical innovation by demonstrating both efficacy and long-term safety, in accordance with the principles of evidence-based aesthetic surgery.⁷

METHODS

A retrospective observational cohort study was conducted using data extracted from the medical records of patients operated on by the principal author, who originally developed both the ARCO and RIBOSS techniques. The study period extended from November 2023 to May 2024, corresponding to the initial implementation of the ARCO procedure and the minimum period required for postoperative follow-up.

Patients

The study population consisted of all patient records who underwent anterior rib osteotomy and internal fixation with platinum plates at Bucaramanga and Bogota, Colombia (November 2023–May 2024). All patients underwent presurgical assessments to determine if the patient can get an anterior rib cage remodeling surgery and to plan the surgical procedure; it required a computed tomography (CT) scan of the chest, spirometry, medical history, and physical examination. We excluded patients who had medical history of osteoarticular tissue diseases, previous chest surgery or trauma, coagulation disorders, chronic lung diseases, psychiatric disorders, and adverse reaction to osteosynthesis material; also, patients older than 45 years with risk of osteoporosis, patients with a body mass index (BMI) greater than 30, and those with uncontrolled systemic diseases and oncology diagnosis or a short life expectancy were excluded.

Materials

The data for this study were extracted from the patient database. The operational database included the following variables:

• Sociodemographic information: age, sex, race, weight, height, and BMI.

• Clinical information: pre- and postsurgical spirometry values (3 mo after); pre- and postsurgical rib cage perimeter; pre- and postsurgical CT scan rib images; surgical procedures performed; duration of surgery; before, during, and after rib fracture fixation compliance and PICO (population, intervention, comparison, outcome) values; anticoagulation and antibiotic prophylaxis; satisfaction scale results; and surgical complications.

ARCO Surgery

• 1.Both general (inhaled and intravenous) and local (ultrasound-assisted nerve blockage and wound infiltration) anesthesia are required for surgery.
• 2.The procedure begins with the patient in a supine position.
• 3.
  Marking: Perform 3 lines for the surgical marking:

  • H line: From the sternal notch toward the anterior–lower border of the rib cage.
  • A line: From the anterior axillary line toward the anterior–lower border of the rib cage, meeting with the H line.
  • V line: vectorial line from the medioclavicular line to the meeting point of the H–A lines (Fig. 1).
• 4.Following the marking made, we mark a 2 cm incision on the mammary fold and the V line.
• 5.Use palpation or ultrasound to mark the lower border of ribs 6, 7, and 8 in the V line (Fig. 2).
• 6.Through 2-cm-long incision, dissect in layers, from the skin to the subcutaneous tissue and the muscular fascia of the serrato muscle.
• 7.Once at the rib margin plane, elevate the periosteum with a 5-mm Joseph periosteal elevator until the rib is exposed.
• 8.Use a piezotome (Cube 2022, FINAPOLLINE, Merignac, France) to cut the external cortical layer of the rib bone until you reach 3–4 mm depth following the V line.
• 9.Apply increasing perpendicular pressure over the anterior costal cartilage and ribs to execute a greenstick fracture of the rib. This maneuver will preserve the integrity of vascular and nervous structures without the risk of pleural injury.
• 10.Repeat steps 6–8 over the sixth, seventh, and eighth ribs through the same incision.
• 11.A 1.5-mm straight titanium plate (MatrixRIB Fixation System; Synthes LLC, Johnson & Johnson, Monument, CO) must be cut into 4 segments of 5 holes each, and the curvature of each segment should be adjusted using a plate bender.
• 12.Measure the angle of the plate using a protractor. The curvature is adjusted depending on the individual preoperative assessment and the angulation achieved with the fracture and the pressure applied to the anterior costal cartilage.
• 13.Use a guide to fix a 5-hole titanium plate (2.4 to 2.9 cm long) to the rib fracture.
• 14.Use a drill to place the 6- or 8-mm screws in position: distal (2) and medial (2) screws stabilize the fracture. Keep the central hole aligned with the fracture and without a screw.
• 15.Fix all treated ribs on each side of the patient with plates while performing the anterior compression maneuver to maintain the fracture open and prevent plate detachment.
• 16.Verify the integrity of noble structures and pleura.
• 17.Finally, layered closure is done with 3-0 polyglactin 910 for the deep and subdermal planes. The skin is closed with subcuticular sutures (3-0 poliglecaprone 25).
• 18.The wound is covered with a sterile gauze and tape.

Fig. 1.

H, A, and V marking lines. Surgical marking for ARCO procedure.

Fig. 2.

H, A, and V lines and the marking of the lower border of ribs (No. 6, 7, and 8). Marking of the lower border of the ribs (No. 6, 7, and 8) over the V line in a real surgical patient.

See Video 1 for the surgical technique performed step by step on a real patient and Video 2 for the 3-dimensional animated representation of the surgical technique. (See Video 1 [online], which shows step by step how to perform the ARCO surgical technique on a real patient during a live surgery.) (See Video 2 [online], which shows step by step the 3-dimensional animated representation of the ARCO surgical technique, a clean version to easily understand the procedure.)

Video 1. This video shows step by step how to perform ARCO surgical technique on a real patient during a live surgery.

Download video file ^{(60.8MB, mp4)}

Video 2. This video shows step by step the three-dimensional animated representation of ARCO surgical technique, a clean version to better understand procedure.

Download video file ^{(11.7MB, mp4)}

Outcomes Evaluation

The evaluation of outcomes was divided into 2 primary domains: procedural safety and aesthetic effectiveness.

Safety and Respiratory Function

To confirm that the ARCO procedure did not compromise respiratory function, several intraoperative and postoperative parameters were assessed. Pulmonary compliance and peak inspiratory pressure (PpK) values were recorded at 3 key stages of the operation: before the rib fracture, during fixation, and after fixation. In addition, spirometry was performed both preoperatively and at 6 weeks postoperatively to monitor potential variations in respiratory volumes.

The absence of pneumothorax or hemothorax was verified intraoperatively using capnography and thoracic ultrasonography. Structural and positional stability of the fixation was confirmed through CT imaging at 6 weeks and 3 months postoperatively, ensuring appropriate rib angulation and correct placement of the osteosynthesis materials.

Aesthetic and Morphological Outcomes

To evaluate the morphological and aesthetic changes resulting from the intervention, the perimeter of the lower rib cage was measured and compared between preoperative and postoperative assessments. Visual documentation was obtained through standardized photographs taken before, during, and after surgery. Patient satisfaction was assessed using the BODY-Q questionnaire, comparing preoperative and postoperative scores to quantify changes in perceived aesthetic outcomes and overall satisfaction.

Ethical Considerations

Each patient was informed about the surgical risk and the purpose, methods, sources of funding, and any conflicts of interest related to the study. This research and database management were done in accordance with the Declaration of Helsinki (Fortaleza 2013—Taipei 2016). They were informed about the right to refuse to participate in the study or to withdraw consent to participate at any time. Informed consent (surgical procedure, use of images, and use of data for research) was signed before surgery.

Statistical Analysis

Descriptive statistics were used to characterize the patient information. To demonstrate differences between preoperative measures and postoperative measures, Student t distribution (normal distribution data) and Welch factor (nonnormal distribution data) were used. The level of significance for the P value was less than 0.05. jamovi statistical software (The jamovi project, Australia; version 2.5; retrieved from https://www.jamovi.org) was used for both univariate and multivariate analyses.

RESULTS

A total of 34 patients were included in the study. The mean age of patients was 34.8 years (SD, 6.35 y), with a mean height of 1.73 m (SD, 0.07 m), mean weight of 66.9 kg (SD, 8.80 kg), and mean BMI of 25.1 kg/m² (SD, 2.63 kg/m²). Regarding gender distribution, 32 (94.1%) patients were woman and 2 (5.9%) identified as transgender. Most participants were Hispanic (91.2%), whereas 8.8% identified as White. None of the patients presented significant comorbidities. However, 55.5% reported a history of previous plastic surgery procedures (Table 1).

Table 1.

Demographic Characteristics

Variable	Measure of Central Tendency or %	Dispersion Measurement
Age, y	Mean: 34.8	SD: 6.35
Sex, n (%)	Total: 34	NA
Female	32 (94.1)
Male	2 (5.9)
Weight, kg	Mean: 66.9	SD: 8.8
Height, m	Mean: 1.73	SD: 0.07
BMI, kg/m2	Mean: 25.1	SD: 2.63
Ethnicity, n (%)	Total: 34	NA
Hispanic	31 (91.2)
White	3 (8.8)
Medical history, n (%)	Total: 34	NA
Yes	0 (0)
No	34 (100)
Plastic surgical history, n (%)	Total: 34	NA
Yes	19 (55.8)
No	15 (44.1)

NA, not applicable.

The mean surgical time for the ARCO procedure was 311 minutes (SD, 106 min). Combined procedures were common: 54.6% of patients underwent liposuction + breast augmentation + ARCO, 30.4% underwent liposuction + ARCO, and 15% underwent ARCO alone. The mean liposuction volume was 4165 mL (SD, 950 mL). Only 1 (2.9%) patient experienced a postoperative complication, which consisted of unilateral suture dehiscence (Table 2).

Table 2.

Surgical Intervention Variables

Variable	Measure of Central Tendency or %	Dispersion Measurement
Surgical time, min	Mean: 311	SD: 106
Surgical procedures, n (%)	Total: 34	NA
1. ARCO	5 (15)
2. Liposuction + ARCO	11 (30.4)
3. Breast augmentation + liposuction + ARCO	18 (54.6)
Liposuction volume, mL	Mean: 4165	SD: 950
Complication, n (%)	Total: 34	NA
Yes	0 (0)
No	34 (100)

NA, not applicable.

The ARCO technique resulted in a median reduction of 2 cm in the lower rib cage perimeter, a change that was statistically significant (Mann-Whitney U = 190, P < 0.001). The osteosynthesis plates were fixed at angles ranging from 35 to 40 degrees in all cases (Table 3).

Table 3.

ARCO Intervention and Intraoperative Respiratory Values

Variable	Measure of Central Tendency	Dispersion Measurement	Test
	Median	IQR
Inferior rib cage perimeter, cm			Mann-Whitney U = 190, P < 0.001
Before ARCO	76	2
After ARCO	74	1
PpK, mm Hg			Kruskal–Wallis ANOVA = 33.43, P < 0.001*
Before Fx	19	1.75
Open Fx	17.4	2
Fixed Fx	19	1.75
PpK, mm Hg			Mann-Whitney U = 486, P = 0.23
Before Fx	19	1.75
Fixed Fx	19	1.75
Pulmonary compliance, mL/cm H2O			NA
Before Fx	35	2
Open Fx	35	2.75
Fixed Fx	35	2

*Statistical significance.

Fx, fracture; NA, not applicable.

Intraoperative respiratory monitoring demonstrated a median PpK of 19 mm Hg (interquartile range [IQR], 1.75 mm Hg) before controlled rib fracture, 17.4 mm Hg (IQR, 2 mm Hg) during fracture, and 19 mm Hg (IQR, 1.75 mm Hg) after stabilization. Although overall differences were significant (Kruskal–Wallis analysis of variance [ANOVA] = 33.43, P < 0.001), there was no statistically significant difference between prefracture and poststabilization values (Mann-Whitney U = 486, P = 0.23) (Figs. 3, 4). Pulmonary compliance remained stable throughout all 3 stages, with a median value of 35 mL/cmH₂O (Kruskal–Wallis ANOVA = 1.08, P = 0.58) (Fig. 5).

Fig. 3.

Box plot: ARCO intraoperatory PpK values, no. 1. Mean and median PpK values before rib fractures, during open fractures, and after fixing the rib fractures. Cx, surgery, Fx, fracture.

Fig. 4.

Box plot: ARCO intraoperatory PpK values, no. 2. Mean and median PpK values before rib fractures and after fixing the rib fractures. Cx, surgery, Fx, fracture.

Fig. 5.

Box plot: ARCO intraoperatory pulmonary compliance values. Mean and median pulmonary compliance values before rib fractures and after fixing the rib fractures. Cx, surgery, Fx, fracture.

Regarding respiratory safety, spirometric measurements confirmed that the ARCO procedure did not compromise pulmonary function. The median forced vital capacity (FVC) was 2.79 L (IQR, 0.18 L) preoperatively and 2.77 L (IQR, 0.16 L) postoperatively (Mann-Whitney U = 531, P = 0.56). The median forced expiratory volume in 1 second (FEV₁) was 2.19 L (IQR, 0.09 L) before and 2.19 L (IQR, 0.11 L) after the procedure (Mann-Whitney U = 484, P = 0.25). The FEV₁/FVC ratio was 0.80 (IQR, 0.06) preoperatively and 0.78 (IQR, 0.06) postoperatively (Mann-Whitney U = 459, P = 0.14). The peak expiratory flow was 3.62 L (IQR, 0.20 L) before and 3.68 L (IQR, 0.22 L) after surgery (Mann-Whitney U = 527, P = 0.53). The mid-forced expiratory flow 25%–75% was 1.95 L (IQR, 0.16 L) preoperatively and 1.89 L (IQR, 0.12 L) postoperatively (Mann-Whitney U = 496, P = 0.31) (Table 4).

Table 4.

ARCO Intervention and Spirometry Values

Variable	Measure of Central Tendency	Dispersion Measurement	Test
	Median	IQR
FVC, L			Mann-Whitney U = 531, P = 0.56
Before ARCO	2.79	0.18
After ARCO	2.77	0.16
FEV1, L			Mann-Whitney U = 484, P = 0.25
Before ARCO	2.19	0.09
After ARCO	2.19	0.11
FEV1/FVC			Mann-Whitney U = 459, P = 0.14
Before ARCO	0.8	0.06
After ARCO	0.78	0.06
PEF, L			Mann-Whitney U = 527, P = 0.531
Before ARCO	3.62	0.2
After ARCO	3.68	0.22
FEF 25–75, L			Mann-Whitney U = 496, P = 0.31
Before ARCO	1.95	0.16
After ARCO	1.89	0.12

FEF 25–75, mid-forced expiratory flow 25%–75%; PEF, peak expiratory flow.

Patient satisfaction, assessed using the BODY-Q questionnaire, demonstrated significant postoperative improvement in the “chest area” domain. The mean preoperative satisfaction score was 75.4 ± 5.21, which increased to 92.0 ± 5.2 at 7 days postoperatively and further to 96.4 ± 2.48 at 3 months postoperatively. This improvement was statistically significant (Welch ANOVA = −224, P < 0.001) (Table 5).

Table 5.

ARCO BODY-Q Satisfaction Score: Chest Section

Variable	Measure of Central Tendency	Dispersion Measurement	Test
	Mean	SD
Chest satisfaction			Welch’s ANOVA= −224, P < 0.001*
Before ARCO	75.4 points	5.21
7 d after ARCO	92 points	5.2
3 mo after ARCO	96.4 points	2.48

*Statistical significance.

DISCUSSION

The present study introduces a structured approach to anterior ARCO—a technique that modifies the curvature of the sixth, seventh, and eighth ribs to reduce the prominence of the lower rib margin and enhance thoracic aesthetics in body contouring surgery (Figs. 6, 7). This procedure provides a targeted solution for lower thoracic cage deformities within the horizontal plane.⁸

Fig. 6.

Front view of ARCO outcome. Comparison of front-view photographs before (A) and after (B) ARCO surgery.

Fig. 7.

Lateral view of ARCO outcome. Comparison of lateral-view photographs before (A) and after (B) ARCO surgery.

ARCO involves creating a controlled greenstick fracture of the lower ribs followed by fixation with osteosynthesis plates (Figs. 8, 9). This approach preserves the structural integrity and protective function of the thoracic cage, offering a distinct advantage over older methods that relied on partial cartilage resection or complete fractures of the anterior chest wall.^1,7 Such earlier techniques could leave internal organs—such as the liver and stomach—insufficiently protected, posing serious risks in the event of trauma.

Fig. 8.

Rib cage modification after ARCO. CT scan images showing differences before (A) and after (B) ARCO surgery.

Fig. 9.

ARCO visual rib cage changes. Visual differences in a patient after unilateral ARCO procedure.

As with any surgical innovation, meticulous preparation and technical precision are required to mitigate potential risks. Mediolateral rib fractures have been associated with a higher incidence of pneumothorax and hemothorax.⁹ To prevent these complications, ARCO induces an anterior greenstick fracture that maintains continuity of the posterior rib margin, preserving the neurovascular bundle. The fracture is performed using a piezotome emitting ultrasonic waves at frequencies between 25 and 29 Hz, well below the threshold required to damage neurovascular structures (>50 Hz).¹⁰ The use of osteosynthesis fixation promotes optimal bone healing, prevents fracture displacement, reduces chronic pain, and ensures immediate stabilization of the rib curvature, thus eliminating the need for postoperative compression corsets, which are often required in other rib contouring methods.^5,11

Our findings support the safety of ARCO. Intraoperative monitoring demonstrated that PpK and pulmonary compliance remained stable before and after fixation, indicating that rib remodeling does not compromise intrathoracic pressure or lung mechanics. Although a transient decrease in PpK was observed during the open fracture phase, this change was minimal and within physiological limits, lacking clinical relevance.¹² Postoperative spirometry at 3 months confirmed the absence of restrictive or obstructive respiratory alterations, with no statistically significant differences in FVC, FEV₁, FEV₁/FVC, peak expiratory flow, or mid-forced expiratory flow 25%–75%. These results demonstrate that ARCO preserves pulmonary function despite modification of the lower anterior rib curvature.

Only 1 of 34 (2.9%) patients developed a minor complication—unilateral suture dehiscence—highlighting the low morbidity associated with the technique. This safety profile is comparable to that reported for RIBOSS, a posterior rib remodeling technique that also uses osteosynthesis for stabilization.^5,11

The risk of pneumothorax during ARCO is inherently low, as the entire procedure is performed along the superior rib border, minimizing the likelihood of pleural injury. Intraoperative and postoperative thoracic ultrasonography is routinely performed to exclude pneumothorax or hemothorax. To standardize this assessment, our team developed the Rib Evaluation and Detection protocol, although any validated ultrasound-based method may be used. In the rare event of pneumothorax, the ARCO incision—located in the inframammary fold near the midclavicular line—allows for conventional chest tube placement through the fifth intercostal space at the midaxillary line, ensuring safe management of potential complications.

Patient satisfaction following ARCO was consistently high, showing a steady and significant improvement throughout the follow-up. Preoperatively, the mean BODY-Q chest-area score was 75.4 ± 5.21, reflecting dissatisfaction associated with rib margin prominence or mild congenital deformity, which is estimated to affect up to 10% of individuals seeking chest contour refinement.¹³ Postoperative satisfaction rose to 92.0 ± 5.2 at 7 days and 96.4 ± 2.48 at 3 months. The BODY-Q instrument, validated in multiple plastic surgery populations,^14,15 reliably captured these improvements, confirming that patients perceive a marked enhancement in anterior thoracic aesthetics and self-image.

Finally, as there are no established parameters by the International Air Transport Association regarding when it is indicated for a postoperative plastic surgery patient to return home,¹⁶ patients who underwent medical tourism were cleared to travel back to their homes after 15 days postoperatively, and they had completed their recovery sessions with hyperbaric chamber therapy. All of them needed to demonstrate the stability of the fracture through a control tomography, no evidence of infection, and absence of anemia. All these measures were taken with the intention of ensuring the utmost safety of our patients, considering that the environment inside a pressurized aircraft is unique and there are physiological changes when flying in an airplane.^17,18

The study has certain limitations. The sample size was modest, and the follow-up period (3 mo) may not fully capture late complications or long-term outcomes. Additionally, as all procedures were performed by a single surgeon, further multicenter studies involving independent operators are needed to validate the reproducibility and generalizability of the ARCO technique.

The ARCO technique thus represents a safe, reproducible, and innovative approach to anterior rib remodeling. By adjusting the curvature of ribs 6–8, the ARCO technique achieves a measurable reduction in thoracic perimeter at the eighth-rib level and a visibly improved anterior chest contour (comparison between Figs. 2 and 10). The use of titanium plate osteosynthesis provides immediate, stable fixation, obviating the need for external compression garments and reducing malunion-related complications. Intraoperative and postoperative respiratory parameters remained statistically and clinically unchanged, reinforcing the safety profile of the procedure. Furthermore, the substantial improvement in BODY-Q satisfaction scores confirms the aesthetic efficacy and patient-centered value of the technique.

Fig. 10.

Lateral view of immediate postoperative ARCO outcome. Aesthetic appeal of the anterior rib margin just after the ARCO procedure.

DISCLOSURE

The authors have no financial interest to declare in relation to the content of this article.

ACKNOWLEDGMENT

The products used in this study were ultrasonic piezotome (Cube 2022, FINAPOLLINE, Merignac, France) and MatrixRIB Fixation system (Synthes LLC, Johnson & Johnson, Monument, CO).