Clinical and radiographic outcomes of lumbar decompression and fusion with a novel metal-free cortico-pedicular fixation device: A comparative cohort study

Abstract

Background

There is ongoing interest in less invasive fixation strategies for lumbar fusion that can achieve comparable biomechanical stability and patient outcomes to traditional pedicle screws. The purpose of this study was to compare the novel metal-free polyether ether ketone cortico-pedicular fixation device (Karma Fixation System; Spinal Elements) with conventional pedicle screw fixation in the largest clinical series reported to date.

Methods

This retrospective comparative cohort study included 20 consecutive patients who underwent lumbar fusion with the cortico-pedicular fixation device and 20 consecutive controls treated with conventional pedicle screw fixation. Outcome measures included same-level reoperation rate within 12 months, radiographic fusion assessed on computed tomography, and patient-reported outcomes (Oswestry Disability Index and Visual Analog Scale for back and leg pain) at 12 months.

Results

In the cortico-pedicular fixation group, 5 patients (25%) required reoperation with pedicle screw fixation for pseudarthrosis and recurrent symptoms at a mean of 7.6 months (reoperation rate at L2–L3 was 50%). Among patients with computed tomography imaging at ≥6 months (range 6–17 months), fusion was observed in only 3 of 16 assessable levels (18.8%), with inferior articular process fractures identified in 9 levels. In the control group, no structural reoperations were required, and posterolateral fusion was achieved in 10 of 11 assessable levels (91%). After excluding cases requiring revision, there were no significant differences in patient-reported outcomes between groups.

Conclusions

The cortico-pedicular device demonstrated high rates of pseudarthrosis and inferior articular process fractures. Its use in conjunction with open laminectomy may be inadvisable.

Introduction

Lumbar degenerative disc disease, often accompanied by spinal stenosis and/or spondylolisthesis, frequently results in significant back pain and radiculopathy secondary to narrowing of the spinal canal and compression of exiting nerve roots [[1], [2], [3], [4]]. Surgical treatment for degenerative disc disease with spinal stenosis typically involves decompressive laminectomy to increase the caliber of the spinal canal [2]. When concurrent spondylolisthesis or instability is present, instrumented fusion using pedicle screw fixation is typically performed in conjunction with decompression to stabilize the motion segment and prevent further vertebral slippage [2,[5], [6], [7]]. Although pedicle screw-based constructs are generally well tolerated, surgical insertion is invasive and associated with potential operational risks including neurological injury from screw malposition, hardware infection necessitating removal, or eventual loosening in cases of nonunion. While navigated and robotic-assisted techniques have improved screw accuracy [8], there is ongoing interest in less invasive fixation strategies for fusion that achieve comparable biomechanical stability and patient outcomes [9].

The metal-free polyether ether ketone (PEEK) corticopedicular fixation system (Karma Fixation System; Spinal Elements) is a novel device that received FDA 510(k) clearance in February 2019 for use in spinal degenerative surgery to be used as an adjunct to spinal fusion with bone graft [10]. Unlike conventional pedicle screw instrumentation, the corticopedicular fixation system utilizes flexible PEEK bands passed through curved transosseous tunnels created through the facet-pedicle complex. Bilateral fixation is achieved by tensioning the construct across the motion segment, thereby providing posterior stabilization (illustrated in Fig. 1). Finite element analyses have demonstrated fixation comparable to pedicle screw fixation, and a clinical study of 13 patients has been published with favorable outcomes shown at 6 months [11,12]. This study describes our clinical experience with the corticopedicular fixation system and reports preliminary clinical and radiographic outcomes.

Fig. 1.

Device illustration of the metal-free polyether ether ketone (PEEK) cortico-pedicular fixation system (Karma Fixation System; Spinal Elements. The cortico-pedicular fixation device is shown in situ following open laminectomy and bilateral facet preparation at the operative lumbar level. The implant traverses the facet joint, originating at the pedicle entry zone of the inferior vertebra and engaging the inferior articular process (IAP) of the superior vertebra, providing circumferential fixation of the facet joint. Note: figure created using the AI-assisted design tool FigureLabs. Initial layouts were subsequently manually refined and verified by the authors in Adobe Photoshop and Illustrator software to ensure scientific and anatomical accuracy.

Methods

Study design and patient population

Reporting of this study followed the Strengthening the Reporting of Observational Studies in Epidemiology statement for cohort studies [13]. Following Institutional Review Board approval (No. 18418-64), a retrospective chart review of the electronic medical record was conducted of 20 consecutive patients who underwent elective lumbar decompression and fusion using the novel metal-free corticopedicular fixation between June 2024 and February 2025. A control group consisted of 20 consecutive patients who underwent elective decompression and posterolateral fusion with pedicle screw instrumentation for the same indication from February 2024 to June 2025.

All procedures were performed by the senior author at a single hospital. Indications for surgery in all cases involved grade 1 spondylolisthesis with severe spinal stenosis and degenerative disc disease. No patients in the corticopedicular fixation or control groups underwent interbody placement. No patients underwent surgery for the indication of trauma or fracture, underlying malignancy, osteomyelitis or osteodiscitis, or involved thoracic or sacral (S1) segments. No patients were excluded. Company representatives provided technical guidance during device implantation but had no role in study design, data collection, analysis, manuscript preparation, or publication decisions.

Baseline demographic and clinical variables collected included age, sex, body mass index, diabetes mellitus status, smoker status, Charlson Comorbidity Index score, and prior surgery. Perioperative variables, including estimated blood loss, fusion level(s), laminectomy level(s), discharge disposition, length of stay, and any complications, were also collected.

Radiographic and clinical outcomes

The primary outcomes of this study were reoperation rate and radiographic fusion. Reoperation rate was defined by the number of patients requiring revision surgery with pedicle screw instrumentation at the same level within 12 months. Indication for reoperation was due to severe back pain and/or return of preoperative symptoms with either evidence of dynamic instability of flexion and extension radiographs or pseudarthrosis on computed tomography (CT). Fusion status was assessed on postoperative lumbar spine CT imaging if it occurred ≥6 months after surgery. Fusion was defined as osseous bridging across the facet joint on CT, while pseudarthrosis was defined as no osseous bridging with evidence of segment motion, such as device or pedicle screw haloing. Secondary outcomes included PROs as measured by the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) for back and leg pain at preoperative and 12 months postoperatively. For patients who did not have complete PRO data at each postoperative interval, research staff attempted follow‑up through at least 2 phone calls to obtain missing PROs.

Cortico-pedicular fixation technique

All patients were positioned prone on a Jackson table and underwent open laminectomy using a standard technique. Thereafter, the facet joints at the operative level were identified and exposed, and entry points were established at the pedicle entry zone of the inferior segment and the cortex of the inferior articular process (IAP) of the superior segment. Using the flexible device drilling system, curved tunnels were created through the pedicle and vertebral body cortex on both the left and right sides. The tunnels were then examined with a sounding probe to ensure they were intact without any evidence of cortical breach. Subsequently, the PEEK corticopedicular fixation device was passed bilaterally through each tunnel and secured at the manufacturer's recommended torque and tension. Excess cabling was trimmed. An illustration of the final corticopedicular fixation device installed is shown in Fig. 1. Bone graft acquired from the laminectomy was then applied over the facet joints of the operative level.

Pedicle screw fixation technique

Patients were positioned prone on a Jackson table, and Kirschner-wires were placed at each vertebral level under fluoroscopic guidance. Cannulated pedicle screws were then inserted, connected by rods, and caps were tightened to the manufacturer’s recommendations. Laminectomy was then performed with an open approach using a separate midline incision. Bilateral facet decortication was performed, and bone graft acquired from the laminectomy was applied over the facet joints.

Statistical analysis

Descriptive statistics were used to summarize baseline demographic, clinical, and comorbidity data. Continuous variables are presented as mean ± SD and categorical variables as counts (percentages). Patient demographics, surgical characteristics, and clinical outcomes were compared using Welch’s t test for continuous variables and Fisher’s exact test for categorical variables. The standardized mean difference was also used to assess group comparability. Longitudinal changes in ODI and VAS scores from baseline to 12-month follow-up were assessed using paired t tests. ODI and VAS scores between the corticopedicular fixation and control groups were also compared. PROs were also evaluated for meeting the Minimal Clinically Important Difference (MCID) or achieving Patient Acceptable Symptom State (PASS). The threshold set for the MCID was a change of ≥12.8 for ODI [14] and ≥1.6 for VAS [15]; the threshold for PASS was ≤25 for ODI [16] and 3.3 for VAS [15]. All statistical analyses were conducted using Microsoft Excel (Microsoft Corp.). Significance was set at p < .05.

Results

Patient and surgical characteristics

Twenty patients, with a mean age of 72.8 ± 8.1 years (range 59–90), comprised the corticopedicular fixation group and were compared to 20 control patients, with a mean age of 72.6 ± 10.3 years (range 54–87). No significant differences in patient or operative characteristics were identified between the corticopedicular fixation and control groups. Eight patients in the corticopedicular fixation group and 9 in the control group underwent additional laminectomies above or below the fusion segment, comprising 39 and 37 laminectomy levels, respectively. In the corticopedicular fixation group, no cortical breaches occurred during device implantation. One surgical site infection occurred in the control group. Length of hospital stay was similar between groups, and there were no significant differences in discharge disposition. A detailed comparison of patient and surgical characteristics is further listed in Table 1, Table 2.

Table 1.

Comparison of baseline demographic and patient characteristics of cohorts.

Variable	Cortico-pedicular device	Control	Absolute SMD	p
N	20	20
Age (y)	72.75 ± 8.05	72.60 ± 10.31	0.016	.96
Sex			0.200	.75
Male	11 (55)	9 (45)
Female	9 (45)	11 (55)
Body mass index	32.45 ± 7.27	30.90 ± 5.23	0.245	.44
Current smoker	1 (5)	5 (25)	0.560	.18
Diabetes	11 (55)	8 (40)	0.300	.527
CCI score, mean (range)	4 (2–7)	4.25 (2–9)	0.154	.629
1–2	1 (5)	2 (10)
3–4	13 (65)	13 (65)
≥5	6 (30)	5 (25)
Prior lumbar laminectomy	2 (10)	5 (25)	0.395	.41
Indication			0.250	.70
Degenerative disc disease	15 (75)	17 (85)
Adjacent segment disc degeneration	5 (25)	3 (15)
Number of fused levels	24	23	0.129	.69
1 segment	16 (80)	17 (85)
2 segments	4 (20)	3 (15)
Fused levels			0.048	.98
L2–L3	6 (25)	6 (26.1)
L3–L4	8 (33.3)	7 (30.4)
L4–L5	10 (41.7)	10 (43.5)
Number of laminectomy levels	39	37	0.110	.73
1 level	9 (45)	8 (40)
2 level	4 (20)	7 (35)
3 level	6 (30)	5 (25)
4 level	1 (5)	0

Values are represented as mean ± standard deviation, or count (percentage) unless otherwise noted.

CCI, Charlson Comorbidity Index; SMD, Standardized mean difference.

Table 2.

Comparison of operative outcomes.

Variable	Cortico-pedicular device	Control	p
N	20	20
Estimated blood loss (cc)	79.8 ± 39.8	157 ± 190.3	.09
Perioperative complications
Hematoma or seroma	1 (5)	1 (5)	.99
Infection	0	1 (5)	.99
Length of stay (days)	2.4 ± 1.64	3.4 ± 1.88	.08
Discharge to home	17 (85)	17 (85)	.99
Discharge to rehab	3 (15)	3 (15)	.99
Reoperation within 12 mo	6 (30)	2 (10)	.24
Reoperation for structural reason	5 (25)	0	.047
Reoperation for other reason	1 (5)	2 (10)	.99

Values are represented as mean ± standard deviation, or count (percentage) unless otherwise noted.

Reoperation

In the corticopedicular fixation group, reoperation within 12 months of surgery was required in 6 patients for evacuation of epidural hematoma (n = 1) and pseudarthrosis with severe back pain and return of preop symptoms (n = 5). Thus, the overall reoperation rate in the corticopedicular fixation group for structural cause was 25% (5/20). Individual patient cases in the corticopedicular fixation group, including prior surgery, fusion surgery, postoperative CT finding, and reoperation, are listed in Table 3. Revision surgery consisted of pedicle screw instrumentation via either a lateral (n = 2) or posterior approach (n = 3). These were performed at a mean of 7.6 months (range 4–11) after the initial surgery. Of these patients, one had prior lumbar instrumentation adjacent to the level where the corticopedicular fixation device was used (pt. no.13, Table 3). The five levels requiring reoperation and failures by level are summarized in Table 4, with the most common being L2–L3 (3/6, 50%). No reoperations were performed in patients who underwent 2-level corticopedicular fixation.

Table 3.

Summary of surgery, fusion, and reoperation required for cortico-pedicular device patients.

No.	Age, sex	Surgery history, years prior	Cortico-pedicular device fixation surgery	CT findings, months later	Reoperation, date
1	70 M	L4–L5 TLIF, 9 y	L2–L4 lami, L3–L4 fusion	n/a	0
2	77 F	None	L2–L5 lami, L4–L5 fusion	IAP fractured, pseudarthrosis, 6 mo	L2–L5 Fusion at 6 mo
3	70 M	None	L3–S1 lami, L4–L5 fusion	IAPs fractured, pseudarthrosis, 14 mo	0
4	68 M	L3–L4 TLIF, 10 y	L2–L3 lami and fusion	IAPs fractured, pseudarthrosis, 13 mo	0
5	86 M	L4–L5 TLIF, 5 y	L2–L3 lami and fusion	IAPs fractured, pseudarthrosis, 8 mo	L2–L3 DLIF at 8 mo
6	74 F	None	L3–S1 lami, L3–L5 fusion	L3–L4 fused, L4–L5 pseudarthrosis, 11 mo	0
7	73 M	None	L2–L4 lami and fusion	IAPs fractured, pseudarthrosis, 13 mo	0
8	64 M	None	L2–L5 lami, L4–L5 fusion	n/a	0
9	62 M	L4–L5 TLIF, L2–L3 lami, 4 y	L2–L4 lami and fusion	IAPs fractured, pseudarthrosis, 17 mo	0
10	90 F	L5–S1 TLIF, 4 y	L3–L4 lami and fusion	Pseudarthrosis, 11 mo	L3–L4 TLIF at 11 mo
11	74 F	None	L3–L5 lami and fusion	L3–L5 facets fused, 15 mo
12	66 F	L4–L5 TLIF, 5 y	L2–L3 lami and fusion	IAPs fractured, 3 mo	L2–L3 TLIF at 4 mo
13	67 F	L3–L4 TLIF, 6 y	L2–L3 lami and fusion	Pseudarthrosis, 9 mo	L2–L3 DLIF at 9 mo
14	72 F	None	L1–L5 lami, L4–L5 fusion	Unilateral pars fracture, L4–L5 facets fused, 12 mo	0
15	59 F	L4–L5 TLIF, 10 y	L3–L4 lami and fusion	Pseudarthrosis, 6 mo	0
16	85 F	None	L4–L5 lami and fusion	n/a	0
17	81 M	None	L2–L5 lami, L4–L5 fusion	n/a	0
18	73 M	None	L3–L4 lami and fusion	n/a	0
19	69 M	L3–L4 lami, 3.5 y	L4–L5 lami and fusion	n/a	Hematoma evacuation at 1mo
20	75 M	None	L2–L5 lami, L4–L5 fusion	n/a	0

Age is represented in years.

CT, computed tomography; F, female; M, male; IAP, inferior articular process of the facet joint; lami, laminectomy; TLIF, transforaminal lumbar interbody fusion; DLF, direct lateral lumbar interbody fusion; n/a, not available; mo, months; y, years.

Table 4.

Summary of cortico-pedicular device failures and reoperation.

Surgical level	Failure rate per level*	Reoperation total	Reoperation rate by level
L2–L3	5/5 (100)	3 (15.0)	3/6 (50.0)
L3–L4	4/6 (66.7)	1 (5.0)	1/8 (12.5)
L4–L5	4/5 (80.0)	1 (5.0)	1/10 (10.0)

^⁎Assessed on computed tomography. Values are represented as count (percentage).

In the control group, 2 patients underwent reoperation for wound infection (n = 1) and evacuation of a seroma (n = 1). No reoperations (0%) for structural causes were required within 12 months of surgery or at the longest available follow-up beyond 12 months.

Fusion

In the corticopedicular fixation group, 13 of 20 patients had postoperative CT performed, at a mean of 10.5 months (range 3–17) after surgery. Of these, 12 CTs were performed ≥6 months after surgery and used to assess the degree of posterior fusion across the facet joint. Four patients from this group had undergone 2-level fusion, allowing for individual assessment of 16 total fusion levels. Four segments in 3 patients showed bilateral osseous bridging across the facet joints (pt. no. 6, 11, and 14), though one level showed a new pars fracture (pt. no. 14). The remaining 12 segments showed facet joint pseudarthrosis, 9 of which had associated IAP fractures. Demonstrative cases are shown in Fig. 2 (pt. no. 7) and Fig. 3 (pt. no. 12).

Fig. 2.

Axial (A), coronal (B), and sagittal (C) views of a computed tomography (CT) image performed 13 months after L2–L4 laminectomy and fusion with the cortico-pedicular fixation device (pt no. 7). The left L2–L3 level is shown (C), with bilateral haloing evident in facet joints around the fixation device (A–C) and a fracture of the left L2 inferior articular process (B and C). Though he initially had a good recovery, the patient developed worsening low back pain at 12-month follow-up, prompting this CT image. He declined a revision fusion surgery.

Fig. 3.

Axial (A), coronal (B), and sagittal (C) views of a computed tomography (CT) image performed 6 months after L2–L5 laminectomy and L4–L5 fusion with the cortico-pedicular fixation device (pt no. 2). The right L4–L5 level is shown (C), with pseudarthrosis of the facet joints, haloing evident in the left superior articular process of L5 (A and B), and fracture of the right L4 inferior articular process (A and C). This patient had a good outcome at 90-day follow-up yet returned to our clinic with severe back pain 6 months after surgery when this CT was obtained, ultimately undergoing pedicle screw fixation.

In the control group, 13 of 20 patients had postoperative CTs available, at a mean of 8.8 months (range 4–14) after surgery. Of these, 11 CTs were performed ≥6 months after surgery and showed fusion in 10 of 11 assessable levels (demonstrative case shown in Fig. 4). One patient who underwent L3–L4 posterolateral fusion demonstrated haloing around the L4 screws at 8 months but was only mildly symptomatic and did not require revision surgery at the longest available follow-up of 17 months.

Fig. 4.

Axial (A), coronal (B), and sagittal (C) views of a computed tomography (CT) image performed 14 months after L4–L5 laminectomy and fusion with pedicle screw fixation. Good posterolateral fusion is shown (A and B). The patient continued to do well on last follow-up.

PROs

In the corticopedicular fixation group, 14 patients had PROs at 12 months, and after excluding the 5 reoperation cases, 11 of 15 (73.3%) were available. In the control group, 16 of 20 patients (80%) had available data at 12 months.

No significant differences in preoperative PROs were identified between groups. In the corticopedicular fixation group, there was significant improvement from baseline at 12 months in ODI (p = .012), with none in VAS back pain (p = .155) or VAS leg pain (p = .417). In the control group, there was significant improvement from baseline at 12 months in ODI (p < .001) and VAS back pain (p = .006), with none in VAS leg pain (p = .485). The change in ODI, VAS back, or VAS leg from baseline to 12-months was not significantly different between groups, nor was the proportion of patients achieving MCID or meeting PASS criteria. The comparative analysis is summarized in Table 5.

Table 5.

Patient-reported outcomes at 12-months, excluding reoperation cases.

	Cortico-pedicular device*	Control	p
ODI	N = 11	N = 16
Preop	38.8 ± 14.0	43.6 ± 15.0	.411
Δ at 12 mo	14.36 ± 15.64	23.8 ± 17.14	.162
p	.012	<.001
MCID or PASS	7 (63.6)	15 (93.8)	.125
VAS back
Preop	5.93 ± 3.35	5.50 ± 3.03	.740
Δ at 12 mo	2.27 ± 4.9	3.57 ± 4.13	.480
p	0.155	0.006
MCID or PASS	7 (63.6)	13 (81.3)	.662
VAS leg
Preop	5.07 ± 4.37	3.94 ± 3.80	.499
Δ at 12 mo	1.55 ± 6.06	1.23 ± 5.34	.889
p	0.417	0.485
MCID or PASS	8 (72.7)	13 (81.3)	.662

Values are represented as mean ± SD or number of patients (%) unless otherwise noted.

mo, months; ODI, Oswestry Disability Index; VAS, visual analog score; PRO, patient-reported outcomes; MCID, minimal clinically important difference; PASS, patient acceptable symptom state.

^⁎Excludes patients who underwent revision surgery with instrumented fusion.

Discussion

In this comparative cohort study, the reoperation rate for structural failure within 12 months after lumbar decompression and fusion was 25% with the novel corticopedicular fixation device and 0% in the control group with pedicle screw fixation. Postoperative CT imaging in the corticopedicular fixation group demonstrated a high rate of facet joint pseudarthrosis and IAP fractures. Even under a liberal estimation, assuming solid facet fusion occurred in all patients without CT imaging, the rate of fracture and pseudarthrosis remains unacceptably high. Notably, most cases of nonunion exhibited haloing around the nonmetallic construct (Figs. 2A, B and 3B). With ongoing segmental motion, bony remodeling appears to occur, leading to progressive thinning of the surrounding elements and resulting in eventual IAP fracture in some cases. This mechanism likely explains the device’s performance in a postlaminectomy setting. Based on these findings, we recommend cautious use or avoidance of this device in conjunction with open laminectomy or decompression. Avoidance altogether at higher lumbar levels may be advisable where facet joint mass and pedicle dimensions are smaller, as seen by the 50% L2–L3 reoperation rate in the corticopedicular fixation group. This creates a potential limitation in applicability since decompressive laminectomy is the cornerstone of surgical treatment for lumbar spinal stenosis.

Importantly, there were no failures of the PEEK corticopedicular fixation device itself, but rather the surrounding bony elements or lack of facet fusion. Use of an interbody device may provide more static segmental conditions that better support posterior facet fusion with this system, although there is no established biomechanical rationale for this. However, the control group with pedicle screw fixation similarly lacked interbody placement yet had a low rate of pseudarthrosis and no reoperations. In the corticopedicular fixation group, PROs demonstrated a statistically significant improvement in ODI, but not in VAS leg or back pain scores. In the control group, both ODI and VAS back pain scores improved significantly. A substantial proportion of patients in both groups achieved MCID or PASS thresholds (Table 5). In ODI, more patients in the control group reached these thresholds (93.8%) compared with the corticopedicular fixation group (63.6%), though not significantly. It is important to note that because a decompressive laminectomy was performed in all patients, and the primary surgical indication was severe lumbar stenosis with grade ≤1 spondylolisthesis, it remains difficult to attribute the observed PRO improvements specifically to the choice of pedicle screw versus corticopedicular fixation fusion.

Eastlack et al. [11] previously performed a finite element analysis demonstrating that the corticopedicular fixation construct provided posterior stability comparable to traditional pedicle screw fixation. They appropriately called for clinical studies to validate these biomechanical findings [11]. To date, only one prior clinical study has evaluated this novel corticopedicular fixation system. Nunley et al. [12] reported favorable outcomes in the setting of supplemental fixation for lumbar interbody fusion [12]. The findings of their study at the 6-month follow-up were overwhelmingly positive. However, only two patients in that series underwent a laminectomy.

At the time of our study, the FDA indication for the corticopedicular fixation system was relatively broad: use as an adjunct to spinal fusions with bone graft. Since the completion of this series, the indication has been narrowed significantly to bilateral facet stabilization for fusion as an adjunct to a 1-level interbody lumbar fusion in L1–L5 segments in patients with degenerative disc disease who have failed conservative care, and it must be used with an interbody device [17]. These more restrictive indications may yield more satisfactory radiographic and clinical outcomes. However, this warrants further prospective study.

This study has several important limitations. First, it is a single-surgeon, single-center comparative series with a modest sample size of 20 patients in each group, which inherently limits generalizability. Second, PRO data were incomplete and, although attempts were made to obtain missing data via phone follow-up, this introduces the possibility of attrition bias. The PRO analysis should be interpreted with caution, as it is likely underpowered. Nevertheless, all patients had adequate follow-up, so the true reoperation rate could be determined. Third, radiographic follow-up was incomplete in each group. Only 13 of 20 patients (65%) in each group had postoperative CT imaging, so the true fusion rate in each group is, to some degree, unknown. Moreover, postoperative CT imaging was obtained based on clinical indications rather than a standardized surveillance protocol, introducing the possibility of selection bias toward symptomatic patients. Fourth, several clinically relevant baseline differences were observed between cohorts, including smoking status, prior lumbar laminectomy, diabetes mellitus, and body mass index. Although these differences were not statistically significant, the limited sample size may have reduced the ability to detect meaningful between-group differences. Accordingly, residual confounding cannot be excluded and should be considered when interpreting the study findings. Finally, all patients underwent a laminectomy and did not undergo interbody placement. Consequently, the results of this study in the corticopedicular fixation group may not reflect outcomes in patients treated without decompression and with concomitant interbody fusion. Despite these limitations, we present our experience transparently. Company representatives were present for device implantation and guidance in all cases. We hope these findings can help guide clinical decision-making for other surgeons considering this novel corticopedicular fixation device.

Conclusion

In this study, the corticopedicular fixation device with open lumbar decompression was associated with frequent pseudarthrosis, facet fractures, and structural reoperation. Further investigation is needed to determine whether outcomes differ when the device is used according to its current indication as supplemental fixation for lumbar interbody fusion. Use in conjunction with a laminectomy, particularly at higher lumbar levels such as L2–L3, may be inadvisable.

Declaration of generative AI and AI-assisted technologies in the manuscript preparation process

During the preparation of this work, the authors created Fig. 1 using the AI-assisted design tool FigureLabs. Initial layouts were subsequently manually refined and verified by the authors in Adobe Photoshop and Illustrator software to ensure scientific and anatomical accuracy.

CRediT authorship contribution statement

DWG: Conceptualization, Project administration, Data Curation, Formal Analysis, Investigation, Methodology, Writing – Original Draft, Writing – Review & Editing, Project Administration, Supervision, Visualization, Resources. RA: Data Curation, Formal Analysis, Investigation, Software, Writing – Original Draft, Writing – Review & Editing, Visualization, Resources. AM: Data Curation, Formal Analysis, Investigation, Software, Writing – Review & Editing, Visualization. HH: Data Curation, Formal Analysis, Writing – Review & Editing, Software, Visualization, Validation. AA: Conceptualization, Writing – Review & Editing, Visualization, Supervision, Resources. PB: Conceptualization, Writing – Review & Editing, Project administration, Supervision, Investigation, Validation.

Declarations of competing interests

Peter Bono is a consultant for Spinal Elements, Stryker, and Globus Medical. All other authors have no potential conflicts of interest to declare.