Efficacy and Safety of Lag Screw Fixation in Unstable Hangman’s Fractures: A Systematic Review and Meta-analysis

Abstract

Objectives

Hangman’s fracture, caused by high-energy hyperextension with axial loading trauma, remains challenging to manage. Unstable types (IIa and III) can be treated by a variety of surgical options. Lag-screw fixation has recently gained attention owing to its compatibility with navigation, minimally invasive instrumentation, and lower surgical morbidity.

Methods

A systematic review and meta-analysis of surgical efficacy and safety of lag screw fixation was undertaken. Nine studies, which included a total of 128 patients, assessed outcomes of lag screw fixation, including neck range of motion, intervertebral angle (C2–C3), postoperative pain (visual analog scale), intraoperative parameters, and complications.

Results

Significant improvements were observed in pooled range of motion (extension: 6.28°, flexion: 5.13°) and correction of the C2 to C3 angle by −3.54° (P < 0.001) vs baseline. Pain decreased across early and late timepoints, although heterogeneity reflects variable follow-up and unreported analgesic/analgesia protocols. Reported complications were low in the included series.

Conclusion

C2 transpedicular lag-screw fixation restores alignment and preserves motion with low reported complications in available case series. Larger comparative trials are needed to define its role relative to fusion techniques.

Clinical Relevance

Direct osteosynthesis of unstable hangman’s fractures via lag-screw fixation offers a viable motion-preserving alternative to C2–C3 fusion. By avoiding fusion, this technique maintains physiological cervical biomechanics and reduces the risk of adjacent segment disease. However, clinicians must carefully weigh these benefits against the technical demands of screw placement and the current lack of high-level comparative evidence.

Level of Evidence

4.

Introduction

Hangman’s fracture refers to a bilateral fracture of the pars interarticularis of the C2 vertebra, resulting in traumatic spondylolisthesis of the axis (C2) from hyperextension with axial loading. It accounts for approximately 7 % of all cervical fractures, second only to odontoid fractures.^1,2 Schneider introduced the term “hangman’s fracture” in 1965 to refer to an avulsion fracture of the lamina of C2, accompanied by traumatic dislocation and listhesis of the axis relative to C3, a mechanism seen in hanging executions.^1,3 Currently, hangman’s fractures typically result from falls, diving incidents, or motor vehicle collisions.⁴

Various classifications include those by Effendi et al in 1981⁵ as well as Levine and Edwards in 1985.⁶ Type I injuries are characterized as non-angulated fractures exhibiting less than 3 mm displacement. Angulation or displacement of the anterior fragment is a hallmark of type II injuries; on average, these fractures cause 11° of angulation and 5 mm of displacement.¹ Type IIa injuries are characterized by reduced displacement and increased angular deformity, typically resulting from flexion injuries and exhibiting instability.⁷ Type III injuries, which are caused by the flexion-compression mechanism, are characterized by a fracture of the neural arch and also involve dislocation of bilateral facets, leading to unstable injuries and neurological complications.¹

Current therapeutic options for hangman’s fractures are challenging, particularly regarding type II and type III as described by Levine and Edwards.⁴ Treatment options comprise conservative management, cervical orthosis, halo-vest orthosis, and surgical interventions.⁷ Nonoperative management is recommended for type I and type II hangman’s fractures, while Levine type IIa and type III fractures typically necessitate surgical intervention.^7,8 Additionally, 20% to 60% of patients develop C2 to C3 kyphosis or pseudarthrosis from long-term conservative therapy with unstable fixation.⁹ Surgical fixation can be performed with a C2 to C3 anterior cervical discectomy fusion (ACDF) or posterior C1 to C3 spinal fusion.^10,11

Direct C2 transpedicular fixation with lag screws, first described by Leconte in 1964,¹² preserves adjacent-level mobility while providing immediate stability.^8,13

We aimed to complete a meta-analysis to evaluate the effectiveness and safety of the C2 transpedicular fixation using a lag screw approach.

Materials and Methods

This systematic review and meta-analysis were conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines.¹⁴ The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42024618045.

Search Strategy

We conducted a comprehensive search across 3 major electronic databases: PubMed/Medline, Embase, and the Cochrane Library, including all studies available up to 4 June 2024. To ensure inclusivity and minimize potential bias, we did not limit the search by language, study type, or publication year. Abstracts in languages other than English were translated using artificial intelligence translation tools and subsequently verified by a human expert (S.E.) for accuracy. We also reviewed the references of all included studies and conducted a search of gray literature through Google Scholar to identify additional relevant studies. Search terms included “hangman fracture,” “C2 fracture,” “lag screw fixation,” and “surgical outcomes.”

Eligibility Criteria

We used the Population, Intervention, Comparison, and Outcome framework to define our study questions. The review included case series, case reports, randomized controlled trials, cohort studies, and case-control studies published between 2000 and 2024 that examined the use of lag screw fixation in patients with hangman’s fractures. To be included, studies needed to report at least 1 of the following outcomes: clinical outcomes, complication rates, reoperation rates, or radiological outcomes. Due to the limited availability of higher-level studies, we included case series and case reports to capture as much relevant data as possible. Duplicate datasets, narrative reviews, and biomechanical or cadaveric studies were excluded.

Screening Process and Data Extraction

After retrieving records from the databases and removing duplicates, data extraction was conducted independently by 2 reviewers (S.K., B.H.). No selection disagreements required third-reviewer arbitration in this review (0 events). Study characteristics were noted. Clinical outcomes included changes in the intervertebral angle (C2–C3), neck range of motion (ROM; extension, flexion, and rotation), and pain levels measured by the visual analog scale (VAS) at various follow-up intervals. Surgical details, including blood loss, operating time, and any complications, were also meticulously recorded. Subgroup analyses were conducted based on fractured type and injury cause. Disagreements during data extraction were resolved with a third investigator (M.G.).

Data Items and Outcome Definitions

For each included study, we extracted the source, method, and time point for all outcomes. Neck ROM was categorized as clinical (goniometer) or radiographic (flexion–extension radiographs), and the preoperative value reflected the first recorded assessment (often emergency/inpatient imaging) when available. The C2 to C3 intervertebral angle was recorded with modality (radiograph vs computed tomography), posture (neutral vs dynamic), and timepoint. VAS timepoints were abstracted verbatim (eg, postoperative day 1, 1 month, 3 months, and final follow-up). We recorded the presence of concomitant/distracting injuries and whether perioperative analgesic/narcotic regimens or pain protocols were reported. Unreported items were coded as “not reported” and treated as missing in synthesis.

Quality Assessment

The Joanna Briggs Institute critical appraisal tool was used to assess case reports and case series.^15,16 All studies selected for inclusion in this systematic review were subjected to appraisal by 2 independent reviewers (S.E. and E.R.).

Data Synthesis and Statistical Analysis

The findings were mainly synthesized narratively because of heterogeneity in study design and outcomes. Where at least 2 comparable datasets were available, a random-effects meta-analysis was performed. Continuous outcomes (VAS, ROM, and C2–C3 angle) were pooled as mean or standardized mean differences, and heterogeneity was quantified with Cochran’s Q and I ². Comparison of ROM and intervertebral angles compared baseline to transpedicular fixation. Sensitivity analyses assessed the influence of single studies, and funnel plots with Egger’s test explored publication bias. All statistics were run in STATA version 17 with statistical significance set at P < 0.05. As several pools contained only 1 or 2 studies, the resulting τ², I ², and pooled effects are reported as descriptive, hypothesis-generating estimates rather than confirmatory evidence.

Results

Study Selection

A total of 261 records were identified, and after removing 131 duplicate records, 130 studies remained for screening. Initial screening of titles and abstracts excluded 100 studies that did not meet the inclusion criteria. Of the remaining 30 articles, 15 studies were excluded due to the inability to retrieve full texts, and an additional 6 studies were excluded after a full-text review for reasons such as irrelevance, incomplete data, or inadequate methodological rigor. Nine studies (7 cohort studies and 2 case reports) encompassing 128 patients met the inclusion criteria (Figure 1).

Figure 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram summarizing the literature search, screening process, and final selection of included studies.

Study Characteristics

Sample sizes ranged from 1 to 25 patients, and ages ranged from 33 to 78  years; 72 % were men, with male-to-female ratios ranging from 1:0 to 18:7. Joanna Briggs Institute scores for individual studies are summarized in Tables 1 and 2.

Table 1.

Quality assessment of case reports using the Joanna Briggs Institute checklist.

Study (Year)	Clear Reporting of Patient History	Clinical Condition Clearly Described	Intervention Described in Detail	Postintervention Outcomes Described	Follow-Up Adequate	Other Details Described	Overall Quality
Rehman et al (2022)17	Y	Y	Y	Y	Y	Y	High
Sugimoto et al (2010)18	Y	Y	Y	Y	U	N	Moderate

Abbreviations: N, no (criterion not met or reported); U, unclear (criterion not clearly addressed or there was insufficient information); Y, yes (criterion was met and adequately reported).

Table 2.

Quality assessment of case series using the Joanna Briggs Institute checklist.

Study	Clear Objectives	Inclusion Criteria Reported	Clear Patient Characteristics	Intervention Described	Outcomes Measured Appropriately	Follow-Up Complete	Statistical Analysis Appropriate	Overall Quality
Liu et al (2023)8	Y	Y	Y	Y	Y	Y	Y	High
Liu et al (2020)19	Y	Y	Y	Y	Y	Y	Y	High
Wang et al (2017)10	Y	Y	Y	Y	Y	Y	Y	High
Kantelhardt et al (2016)20	Y	Y	Y	Y	Y	Y	U	Moderate
Zeden et al (2017)21	Y	Y	Y	Y	Y	Y	Y	High
Li et al (2018)22	Y	Y	Y	Y	Y	Y	Y	High

Abbreviations: N, no (criterion not met or reported); U, unclear (criterion not clearly addressed or there was insufficient information); Y, yes (criterion was met and adequately reported).

Most studies included type II or IIa fractures, and 1 study included patients with type III fractures. Motor vehicle accidents and falls were the most frequently reported causes of injury, accounting for most cases across the studies. Studies were conducted in various countries (eg, China, Germany, Japan, Pakistan, and Egypt). Follow-up ranged from 3 months to 24 months.

Mean operative time was 101  minutes (66–145), and mean blood loss was 197  mL (111–304). Only 1 vertebral-artery–adjacent screw breach and no deep infections or hardware failures were reported. Clinical assessments focused on pain relief (measured by the VAS), improvements in neck ROM (flexion, extension, and rotation), postoperative intervertebral angle (C2–3), and bony fusion rates were well reported, comparing baseline to postoperative fixation. Tables 3 and 4 summarize study characteristics, clinical outcomes, complications, and surgical parameters.

Table 3.

Study characteristics of included articles on lag screw fixation for hangman’s fractures.

Study (Year)	Country	Study Design	Sample Size	Age, y, Mean ± SD	Male/Female Ratio	Fracture Type	Cause of Injury	Measurement Method/Timepoint (ROM/Angle/VAS)
Liu et al (2023)8	China	Case series	22	48.6 ± 15.7	15/7	II: 18; IIA: 4	Car accidents: 15; falls: 7	ROM: measured clinically in degrees at 3 mo, 6 mo, and last follow-up; angle: C2–C3 intervertebral angle on dynamic radiographs (overflexion/overextension) with AD defined; timepoints: 3 mo, 6 mo, and last follow-up; VAS: POD1, 1 mo, 3 mo, and last follow-up.
Liu et al (2020)19	China	Case series	25	45.4 ± 9.3	18/7	II: 17; IIA: 8	Car accidents: 17; falls: 8	ROM: qualitative/“restored to normal” at last follow-up (no numeric series); angle: not specified; VAS: POD1, 1 mo, 3 mo, and last follow-up.
Wang et al (2017)10	China	Case series	21	49.2 ± 17.8	14/7	II: 15; IIA: 2; III: 4	Car accidents: 7; falls: 13; other: 1	ROM: NR; angle: angulation and displacement of C2 on C3 on lateral radiographs at preoperatively, 1 wk postoperatively, and final follow-up; CT at 6 mo and 12 mo; VAS: serial follow-ups (specific timepoints not stated).
Li et al (2018)22	China	Case series	23	42.7 ± 14.3	18/5	AHF patterns A, B, and C	Car accidents: 4; falls: 14; other: 5	ROM: NR; angle: anterior translation and C2–C3 angulation on radiographs; follow-up at 3 mo, 6 mo, 12 mo, and 24 mo; VAS: 3 mo, 6 mo, 12 mo, and 24 mo.
Rehman et al (2022)17	Pakistan	Case report	1	33	1/0	Atypical C2	Car accident	ROM: full/normal at ~8 mo final follow-up; angle: NR; VAS: NR.
Sugimoto et al (2010)18	Japan	Case report	1	69	0/1	Type I	Traffic accident	ROM: NR; angle: NR; VAS: NR (case report, focus on technique); final follow-up radiographs confirm union.
Zeden et al (2017)21	Germany	Case series	12	63.1 ± 17.1	6/6	Type II	Car accidents: 4; falls: 7; other: 1	ROM: NR; angle: NR; fusion verified on CT at ~3 mo; VAS: NR.
Kantelhardt et al (2016)20	Germany	Case series	7	67.8 ± 15.3	4/3	C2 and C3 fractures	Mixed (not specified for all)	ROM: NR; angle: NR; VAS: NR (series on minimally invasive instrumentation; includes hangman subset).
Kantelhardt et al (2012)23	Germany	Case series	16	65	7/9	C2 fractures	Ground-level falls: 14; traffic accidents: 2	ROM: NR; angle: NR; VAS: NR (institutional C2 fracture experience; includes posterior lag-screw cases).

Abbreviations: AD, angular displacement; AHF, atypical hangman’s fracture; CT, computed tomography; NR, not reported; POD, postoperative day; ROM, range of motion; VAS, visual analog scale.

Table 4.

Clinical outcomes and complications of lag screw fixation for hangman’s fractures.

Study (Year)	VAS Final Follow-Up (Score 0–10)	Intervertebral Angle (C2–C3) Postoperative Final Follow-Up	Neck ROM Postoperative Final Follow-Up	Blood Loss, mL	Complications	Operative Time, min	Measurement Method/Timepoint Notes
Liu et al (2023)8	1.1 ± 0.6	Overflexion: 4.5 ± 1.7; overextension: −0.5 ± 0.5; AD: 5 ± 2	Flexion: 38.2 ± 1.9; extension: 40.1 ± 1.6; left flexion: 40.3 ± 1.4; right flexion: 41 ± 1.6; left rotation: 71.2 ± 2.2; right rotation: 70.8 ± 1.6	NR	No procedural or systemic complications	66.1 ± 11.9	Angle: defined from lines parallel to C2 superior and C3 inferior endplates on over-flexion/over-extension radiographs; AD as change across dynamic views; timepoints 3 mo, 6 mo, and last follow-up. ROM: clinical degrees reported at 3 mo, 6 mo, and last follow-up. VAS: POD1, 1 mo, 3 mo, and last follow-up.
Liu et al (2020)19	1.3 ± 0.7	NR	Flexion: 37.9 ± 1.8; extension: 40 ± 1.5; left flexion: 40.1 ± 1.3; right flexion: 40.9 ± 1.7; left rotation: 70.8 ± 2.1; right rotation: 70.4 ± 1.3	288 ± 41.5	No procedural or systemic complications	103.4 ± 14.5	VAS: POD1, 1 mo, 3 mo, and final follow-up; ROM: restored to normal by last follow-up (no numeric series); angle: not specified.
Wang et al (2017)10	1.2 a	AD: 0.6 ± 0.4	NR	137.6 ± 61.7	Procedural complications: 1; systemic complications: 2	33.1 ± 21	Angle: angulation and displacement on lateral radiographs at preoperative, 1 wk postoperatively, and final follow-up; CT at 6 mo and 12 mo; VAS: serial follow-ups (time points not specified).
Li et al (2018)22	1 a	AD: 1.7 ± 1.1	NR	NR	Systemic complications: 1	113.7 ± 29.2	Angle: anterior translation and C2–C3 angulation on radiographs; follow-up schedule 3 mo, 6 mo, 12 mo, and 24 mo; VAS: same timepoints.
Rehman et al (2022)17	NR	NR	Full ROM achieved	NR	No complications	NR	ROM: full at 8 mo final follow-up; VAS/angle: NR.
Sugimoto et al (2010)18	NR	NR	NR	NR	No complications reported	NR	Outcome methods/timepoints: not reported (navigation case report); union on final follow-up imaging.
Zeden et al (2017)21	NR	NR	NR	Negligible	No procedural complications	70.5 ± 12	Fusion assessment by CT at 3 mo; other clinical outcomes reported; VAS/ROM/angle methods: NR.
Kantelhardt et al (2016)20	NR	NR	NR	<10	NR	78 ± 70.2	Series focus on minimally invasive instrumentation parameters (time, blood loss); methods/timepoints for VAS/ROM/angle not reported.
Kantelhardt et al (2012)23	NR	NR	NR	NR	NR	NR	Institutional experience with Iso-C-arm 3D guidance; no VAS/ROM/angle series reported for hangman subset.

Abbreviations: AD, angular displacement; C3D, C-arm 3 dimension; CT, computed tomography; NR, not reported; ROM, range of motion; VAS, visual analog scale (measured on a scale of 0–10).

Note: Data provided as mean ± SD unless otherwise noted.

^aMean.

Efficacy and outcomes

Intervertebral Angle (C2–C3)

The intervertebral angle (C2–C3) was a critical parameter in assessing spinal alignment following lag screw fixation. The pooled effect size was −3.54° (95% CI: −5.54, –1.53, P = 0.001), reflecting a significant and meaningful correction in spinal alignment compared with baseline after surgical intervention. However, there was notable heterogeneity among the studies (I ² = 88.12%; Figure 2).

Figure 2.

Forest plot of pooled changes in the intervertebral angle (C2–C3) following lag-screw fixation, comparing preoperative to final postoperative follow-up. AD, angular displacement.

Neck ROM

The restoration and maintenance of neck ROM were a key outcome across the included studies . Compared with the preoperative baseline, lag‐screw fixation yielded a pooled increase in C2 to C3 extension of 5.79° (95% CI: 4.87, 6.71) at the 3- and 6-month follow-ups. This improvement was sustained at the final follow-up, where the effect size increased to 6.28° (95% CI: 5.30, 7.26), again with no heterogeneity (Figure 3). At 3- and 6-month follow-ups, the pooled effect size for flexion was 4.83° (95% CI: 4.04, 5.63, P < 0.001), and this improvement continued at the final follow-up, reaching 5.13° (95% CI: 4.29, 5.96, P < 0.001). Again, no heterogeneity was observed (I ² = 0.00%), indicating a reliable and uniform effect of surgery (Figure 4) .

Figure 3.

Forest plots illustrating neck extension range-of-motion (ROM) improvements after lag-screw fixation, comparing postoperative outcomes at 3 mo vs 6 mo and final follow-up intervals.

Figure 4.

Forest plots illustrating neck flexion range-of-motion (ROM) improvements after lag-screw fixation, comparing postoperative outcomes at 3 mo vs 6 mo and final follow-up intervals.

Left lateral flexion demonstrated an effect size of 4.35° (95% CI: 3.61, 5.09) at 6 months, increasing to 4.90° (95% CI: 4.09, 5.70) in the final follow-up (Figure 5). Right lateral flexion showed comparable gains, with effect sizes of 5.42° (95% CI: 4.55, 6.29) at 6 months and 4.03° (95% CI: 3.33, 4.73) at the final follow-up (Figure 6) . These improvements were uniform across studies, as evidenced by the lack of heterogeneity in both dimensions.

Figure 5.

Forest plots illustrating left lateral flexion improvements in neck range of motion (ROM) after lag-screw fixation, comparing postoperative outcomes at 3 mo vs 6 mo and final follow-up intervals.

Figure 6.

Forest plots illustrating right lateral flexion improvements in neck range of motion (ROM) after lag-screw fixation, comparing postoperative outcomes at 3 mo vs 6 mo and final follow-up intervals.

Left rotation showed an effect size of 3.80° (95% CI: 3.12, 4.47) at 6 months and 3.93° (95% CI: 3.24, 4.61) in the final follow-up (Figure 7). Similarly, the right rotation improved from 4.03° (95% CI: 3.33, 4.73) in 6 months to 4.37° (95% CI: 3.63, 5.12) in the final follow-up (Figure 8). All pooled ROM gains were statistically significant (P < 0.001).

Figure 7.

Forest plots illustrating left rotation improvements in neck range of motion (ROM) after lag-screw fixation, comparing postoperative outcomes at 3 mo vs 6 mo and final follow-up intervals.

Figure 8.

Forest plots illustrating right rotation improvements in neck range of motion (ROM) after lag-screw fixation, comparing postoperative outcomes at 3 mo vs 6 mo and final follow-up intervals.

Visual Analog Scale

Pain reduction, as measured by the VAS, was a consistently reported outcome across all included studies, reflecting significant postoperative improvements. On the first day following surgery, there was a substantial reduction in VAS scores, with a pooled effect size of –3.85 (95% CI: –4.58, –3.12). This improvement was associated with low heterogeneity (I ² = 12.59%), suggesting consistency in the immediate analgesic effects of the procedure across studies (Figure 9). Baseline and final follow-up VAS values for included studies are summarized in Table S1.

Figure 9.

Forest plots depicting improvements in visual analog scale (VAS) pain scores following lag-screw fixation, comparing preoperative pain to postoperative day 1 (A), 1 mo (B), 3 mo (C), and final follow-up (D). Heterogeneity by timepoint: I ² (A) = 12.59%, I ² (B) = 78.58%, I ² (C) = 46.35%, and I (D) = 78.58%.

The pain reduction further improved at 1 month, with a pooled effect size of –6.80 (95% CI: –8.92, –4.68). However, heterogeneity increased significantly (I ² = 78.58%), reflecting variability in patient populations, surgical techniques, and perioperative pain management protocols.

By the 3-month follow-up, pain relief remained significantly improved, with a pooled effect size of –6.84 (95% CI: –8.29, –5.39], and heterogeneity decreased to moderate levels (I ² = 46.35%). This suggests more uniform results as the initial postoperative variability stabilized over time.

At the longest follow-up period reported, VAS scores decreased by 3.85 points on postoperative day 1 and by –6.93 (95% CI: –9.26, –4.60) at final follow-up. Despite the strong reduction in pain levels, heterogeneity remained high (I ² = 78.58%), likely reflecting differences in follow-up duration, rehabilitation protocols, and patient adherence to postsurgical care recommendations.

Complications

Across all studies, the overall complication rate was <5%. Three studies provided detailed data on intraoperative blood loss, which ranged from 111.21 mL to 304.27 mL, with a pooled mean of 196.86 mL (95% CI: 105.36, 288.37). The variability in reported values was significant (I ² = 97.94%), reflecting differences in surgical complexity, fracture severity, and surgeon expertise (Figure 10).

Figure 10.

Forest plots summarizing operative time (minutes), procedural complication rates, and systemic complication rates associated with lag-screw fixation.

Operating times varied, ranging from 66.1 minutes to 145.4 minutes, with a pooled mean of 101.58 minutes (95% CI: 81.26, 121.90). The high heterogeneity observed (I ² = 95.20%) suggests that factors such as the complexity of the fracture, the surgeon’s experience, and the use of intraoperative imaging guidance influenced surgical duration. No major systemic complications, such as infection, thromboembolism, or hardware failure, were reported across the studies. Zeden et al²¹ highlighted a procedural risk related to the proximity of screws to the vertebral artery. Minor cortical breaches and transient nerve irritation were reported in isolated cases, but no major systemic complications, such as infection or hardware failure, were observed.

Discussion

This systematic review provides strong evidence supporting the use of lag screw fixation as an effective treatment for hangman’s fractures. Across the included studies, this technique consistently demonstrated significant improvements in pooled intervertebral alignment, neck ROM, and pain relief, with minimal complications. These findings highlight its role as a reliable and safe option for managing unstable fractures.

Because early reports of novel techniques often originate from experienced centers and small, favorable series, both effect estimates and complication rates may be optimistically biased. This aligns with the well-described tendency toward selective publication in first-generation case series; thus, real-world performance may show higher variability and potentially higher complication rates than suggested here.

The goal in managing hangman’s fractures is to stabilize the injury while maintaining the natural movement between C1 and C2 and preserving the normal function between C2 and C3.⁸ While type I fractures are generally considered stable and are often treated nonsurgically with good results,²⁴ complications like nonunion, anterior dislocation, and persistent axial pain can occur in the long term.^8,10 In contrast, type II and III fractures typically require earlier surgery, but these procedures come with significant risks.

Given these challenges, lag screw fixation offers a less invasive alternative with promising results, potentially increasing the opportunity for earlier fixation in lower-grade fracture patterns or as an alternative for high-grade patterns requiring fracture reduction. Previous systematic reviews of C2 pars interarticularis (hangman’s) fractures have shown that surgical fixation yields higher fusion rates—99.35% vs 94.14%—compared with nonsurgical management (OR 0.12; 95% CI: 0.02, 0.71).^7,25 Lag screw fixation can also be incorporated with modern polyaxial screw-rod systems with good results.^10,26 Another advantage of surgical fixation can include immediate stabilization without further disruption of musculoskeletal tissue already compromised by trauma.⁸

There is still some debate over the best surgical technique for hangman’s fractures. For instance, Hur et al advocated for ACDF with plating to promote bone union with minimal complications, allow for early mobility, and provide quicker stabilization.²⁷ In the cadaveric biomechanical comparison by Duggal et al, posterior C2 to C3 screw-rod fixation provided significantly greater rigidity than anterior discectomy-and-plating—reducing lateral bending to 0.1 ± 0.0 of intact ROM vs 0.8 ± 0.4 (P = 0.008) and axial rotation to 0.2 ± 0.1 vs 0.8 ± 0.4 (P = 0.04) relative to the injured state.²⁸ Although both ACDF and posterior cervical decompression and fusion show low overall complication rates (ACDF: 13/200 procedures [6.5%]; posterior cervical decompression and fusion: 4/193 procedures [2.1%]),²⁴ these open approaches require extensive soft-tissue dissection and sacrifice segmental C2 to C3 motion. By contrast, lag-screw fixation uses a smaller surgical corridor to preserve ROM while providing immediate stability, as demonstrated in the cadaveric study, where a posterior screw-rod construct limited lateral bending to 0.1× intact ROM vs 0.8× intact ROM (P = 0.008) and axial rotation to 0.2 vs 0.8 (P = 0.04).²⁸

Our analysis also highlights a significant reduction in the C2 to C3 intervertebral angle postsurgery, showing that lag screw fixation is effective in realigning the spine. This finding aligns with several studies^8,19 that reported improvements in the intervertebral angle from 4.5° ± 1.2° postoperatively to 4.1° ± 0.9° at the final follow-up and from 4.8° ± 1.3° postoperatively to 4.2° ± 1.1°, respectively. Retained neck motion is a key factor in preventing long-term complications like chronic pain.²⁹

Importantly, few studies have focused specifically on the efficacy of lag screws in maintaining ROM postoperatively. Unlike posterior fusion techniques, which often limit ROM, lag screw fixation has shown significant improvements in extension, flexion, and rotation during follow-up.^30,31 Liu et al⁸ reported specific improvements in extension angles, with increases from 6.12° postoperatively to 6.28° at the final follow-up. Another study showed that this functional benefit is supported by improvements in flexion as well, with an increase from 4.83° to 5.13° over the follow-up period.¹⁹ The minimally invasive nature of this procedure significantly reduces postoperative pain, with patients often experiencing relief as early as the first day after surgery.³²

Another important finding is the low rate of complications associated with this technique. Compared with more invasive methods like posterior open stabilization, which can lead to higher infection risks, increased blood loss, and longer recovery times, lag screw fixation offers a safer alternative.²¹ While screw misplacement in upper cervical spine surgeries can occur in up to 7% of cases, advances in technology, such as intraoperative computed tomography scans and computer-assisted systems, are improving the accuracy of screw placement and reducing the risk of serious complications.^33,34

Despite the positive results, we observed variations in surgical time and blood loss, likely due to factors such as the surgeon’s experience and the complexity of individual cases.³⁵ For example, Liu et al⁸ reported an average blood loss of 111.21 mL, while Kantelhardt et al²⁰ reported a higher average of 194 mL, likely attributable to differences in surgical technique or patient comorbidities. Wang et al¹⁰ reported a mean operating time of 145.4 minutes, reflecting a more complex patient cohort, while Liu et al⁸ reported shorter times averaging 66.1 minutes, indicative of more streamlined procedures. Although these differences did not affect the overall success of the procedure, they suggest areas for further refinement.

Key data elements should include standardized VAS timepoints (postoperative day 1, 1 month, 3 months, and 12 months) with documented analgesic/narcotic protocols and cumulative dose; ROM source with a unified measurement protocol; C2 to C3 angle method (modality and posture); fracture classification; reduction quality; use of navigation/fluoroscopy; surgeon experience; concomitant injuries; and predefined complications (eg, vertebral artery proximity/breach, neurological change, infection, and reoperation). We also recommend inclusion of functional scales (eg, Neck Disability Index, SF-36/PCS-MCS) and supplementary radiographic parameters analogous to cervical total disc replacement literature to contextualize motion preservation and alignment.

Overall, the favorable outcomes demonstrated in this meta-analysis support lag screw fixation as a reliable and effective treatment option for unstable hangman’s fracture.²² Future studies can potentially consider a randomized clinical trial to better compare the outcomes of lag screw fixation with other anterior or posterior fixation methods. Ideal comparisons would be to compare fixation strategies in minimally displaced fracture patterns (ie, Levine and Edwards types I, II, and IIa). Evaluation of high-grade, unstable fractures (ie, Levine and Edwards type III) may be challenging with lag screw fixation.

Limitations

This meta-analysis is not without limitations. It is based on small case series and reports, with attendant potential for bias. The absence of comparator cohorts (eg, anterior C2–C3 or posterior cervical fusions) precludes head-to-head comparison, and the predominance of Chinese studies restricts generalizability. Several studies were published by the same research group. Outcome heterogeneity, particularly for pain scores at varying follow-up periods, reflects differences in study design, surgical technique, and duration of follow-up. Postoperative analgesia/narcotic regimens were rarely reported, which limits the interpretation of between-study VAS differences, particularly at early timepoints. The presence of concomitant chronic neck pain or polytrauma may also impact pain scores. Limited reporting of secondary outcomes and rehabilitation regimens further restricts comprehensive assessment, while potential publication bias may overestimate benefits and highlights the requirement for more extensive, rigorous research. Nevertheless, these 9 studies comprise the entirety of the current clinical evidence base regarding direct C2 lag-screw fixation; their pooled findings provide interim guidance until larger comparative trials provide higher-certainty estimates and should be viewed as decision support rather than evidence of superiority. The use of a systematic review methodology aimed to review the entire literature, presenting both the supporting data and gaps requiring further study.

Conclusion

This systematic review highlights the effectiveness of lag screw fixation in treating hangman’s fractures. The procedure consistently improved intervertebral alignment, neck ROM, and pain relief, with benefits observed early and sustained through long-term follow-up. Improvements in ROM showed minimal variability, underscoring the reliability of this technique across different populations and clinical settings. Pain reduction was substantial, though some variability was noted in long-term outcomes. The low complication rates, along with manageable operating times and blood loss, confirm the safety of this approach. While these findings support lag screw fixation as an effective treatment, high-quality comparative trials are required to define its role relative to fusion techniques.