Minimally Invasive Short-Segment Cement-Augmented Pedicle Screw Fixation Without Fusion in Osteoporotic Vertebral Compression Fractures With Intravertebral Instability: A Retrospective Analysis

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J Minim Invasive Spine Surg Tech. 2025;10(Suppl 2):S163-S170

Publication date (electronic) : 2025 July 31

doi : https://doi.org/10.21182/jmisst.2025.02012

Niraj B. Vasavada^,1, Bhavin B. Vasavada², Prateek P. Lodha¹, Aayush Vasavada³, Bharat Dhanani¹

¹Department of Spine Surgery, Zydus Hospital, Ahmedabad, India

²Department of Hepatobiliary Surgery, Shalby Hospital, Ahmedabad, India

³NHL Medical College, Ahmedabad, India

Corresponding Author: Niraj B. Vasavada Department of Spine Surgery, Zydus Hospital, SG Road, Thaltej, Ahmedabad – 380054, India Email: nirajvasavada@gmail.com

Received 2024 December 29; Revised 2025 June 23; Accepted 2025 July 3.

Abstract

INTRODUCTION

Osteoporotic vertebral compression fractures (OVCF) are a significant cause of morbidity in the elderly population [1]. Traditional management includes conservative treatments such as bracing, pain management, and antiosteoporotic treatments. However, in cases with intravertebral instability, these conservative measures may be insufficient in providing meaningful clinical relief, often necessitating surgical intervention [2,3]. Percutaneous cement augmentation, either by vertebroplasty or balloon kyphoplasty, is now the standard of care for painful OVCFs when conservative treatments fail or are inadequate [4]. The challenge arises when significant intravertebral instability is present, which can lead to failures during the early postoperative period after cement augmentation procedures [5,6]. Recent advances have introduced minimally invasive fixation techniques aimed at reducing surgical morbidity while providing effective stabilization [7]. This study evaluates the feasibility and clinical outcomes of minimally invasive short-segment cement-augmented percutaneous pedicle screw fixation without fusion in patients with OVCF and intravertebral instability with midterm follow-up.

MATERIALS AND METHODS

4. Surgical Technique

The surgical procedure involved the standard technique for minimally invasive percutaneous pedicle screw fixation [10,11]. All patients were operated under general anesthesia with prone position over standard bolsters placed horizontally. Pedicle screws with fenestrations for cement injection were used. At the fracture level, either unilateral or bilateral pedicle screws were inserted, and cement was injected to fill the anterior column void via the fenestrated screws (Figure 1). The decision of unilateral or bilateral pedicle screws was based on the cost burden to the patient. Bilateral fenestrated screws were inserted at the adjacent levels one above and one below. In 3 initial cases (n=3), index-level screws were not used (Figure 2), and cement was injected into the fractured vertebrae using the standard percutaneous vertebroplasty technique [12,13]. Approximately 2- to 2.5-mL PMMA cement was injected from each screws attempting to fill the vertebra with about 4-mL cement. In 7 initial cases (n=7), the screws at the adjacent levels were not cement-augmented. In the remaining 23 cases, both the index level and the adjacent levels were fixed with cement-augmented screws. Fluoroscopic guidance ensured accurate screw placement and safe cement injection. The procedure did not include posterior fusion. We did not use percutaneous screws for kyphosis correction via distraction between the screws. We accepted postural correction of kyphosis achieved by the prone position.

Figure 1.

L2 osteoporotic vertebral compression fracture with intravertebral instability. (A) Difference of cobb angle from supine to sitting >15°, with ≥50% vertebral body height reduction. (B) Preoperative magnetic resonance imaging (MRI) shows intravertebral fluid sign (Kummel sign). (C) Computed tomography scan shows intravertebral cleft. (D) Postoperative MRI shows cobb angle correction to 3.5˚.

Figure 2.

Short-segment fixation L3 osteoporotic vertebral compression fracture with percutaneous vertebroplasty at index level, without index level pedicle screw. Magnetic resonance imaging (A) and computed tomography (B) scan of L3 compression fracture. Short-segment fixation with index level isolated vertebroplasty anteroposterior (C) and lateral (D) images.

RESULTS

Out of 50 patients operated on between November 2017 and December 2022. Of these, 2 patients (n=2) had previously undergone percutaneous vertebroplasty elsewhere, resulting in endplate fractures around the cement mass. All patients had at least one medical comorbidity (e.g., type 2 diabetes mellitus, ischemic heart disease). All of the patients had been on aggressive antiosteoporosis medical management preoperatively for at least 3 weeks before they were referred to us.

1. Patient Demographics

The 30 patients included in the analysis comprised 21 females and 9 males, with a median age of 66.5 years. The most common level of OVCF was at D12, followed by L1 (Table 1).

Table 1.

Descriptive data

2. Clinical Outcomes

(1) Oswestry Disability Index

The median preoperative ODI was 91, indicating severe disability. At 24 months postoperatively, the median ODI significantly improved to 18 (p<0.01), reflecting a substantial reduction in disability (Figure 3).

Figure 3.

Bar graph demonstrating significant improvement in Oswestry Disability Index (ODI) at 24 months.

(2) Visual analogue scale

The median preoperative VAS score was 8, indicating significant pain. Postoperative VAS scores showed significant improvement at all time points (Figure 4), with median scores of 3, 2, and 1 at 1, 6, and 24 months, respectively (p<0.01). The most marked improvement was observed at 1 month postoperatively, which sustained through the 24-month follow-up (Table 2).

Figure 4.

Line graph showing visual analogue scale (VAS) improving significantly at 1 month. Maximum improvement in VAS was noted at 1 month which was maintained at final follow-up of 24 months.

Table 2.

Post hoc analysis using the Conover test

(3) Kyphosis correction

The median preoperative kyphosis was 14.1°, which improved significantly to 4.4° at 24 months postoperatively (p<0.001, Wilcoxon signed-rank test) providing mean 9.7° kyphosis correction at follow-up. We did not measure intraoperative kyphosis correction due to positioning.

3. Complications

Two patients (6.6%) required additional surgery within 24 months. One patient experienced multiple suprajacent and 1 subjacent OVCF after 1 year (Figure 5), treated with intravertebral stenting and percutaneous vertebroplasty (PVP), and another had a distant-level OVCF (Figure 6), also treated with PVP. No implant failures or loosening were reported. There were no cases of clinically significant cement leakage.

Figure 5.

Suprajacent (D11, D12, L1) and subjacent (L5) osteoporotic vertebral compression fracture at 14 and 17 months postindex procedure (L2–4 short segment). D12 vertebral body stenting and D11, L1, L5 percutaneous vertebroplasty done. (A) Preoperative magnetic resonance imaging. (B) Postoperative lateral view.

Figure 6.

Distant level (D9) new compression fracture at 8 months postindex surgery (D11–D12–L1 short segment). Treated with percutaneous vertebroplasty. (A) Preoperative magnetic resonance imaging. (B) Postoperative lateral view.

DISCUSSION

Advances in the medical management of OVCFs have made surgical intervention less necessary for fractures without intravertebral instability or radiological signs of nonunion [14-16]. However, for patients where medical management fails to relieve pain or where significant intravertebral instability or nonunion is present, surgery may be required. PVP or percutaneous kyphoplasty (PKP) are established techniques for managing such patients with medical fragility [17]. Despite the controversy [18,19], PVP/PKP improved short-term, midterm, and long-term outcomes significantly in the elderly population (>60 years) [17]. However, PVP or PKP can pose a risk of failure in patients with significant intravertebral instability due to the potential for endplate failures around the cement mass, likely due to residual instability. There have been reports suggesting intravertebral instability may lead to failures at the index level [20-22].

Conventionally, these patients were treated with either open short-/long-segment fixation with posterior fusion or with minimally invasive long-segment (2 levels above and 2 levels below the index vertebra) percutaneous pedicle screw fixation [23]. The results of this study indicate that minimally invasive short-segment cement-augmented percutaneous pedicle screw fixation, with index vertebra cement augmentation via fenestrated percutaneous pedicle screws and without fusion, is a feasible and effective treatment for OVCF with intravertebral instability. Significant improvements in ODI and VAS scores suggest that this technique can provide substantial pain relief and functional recovery in elderly patients with minimal complications. Additionally, this approach is less invasive than open surgeries and involves shorter surgical time and reduced radiation exposure compared to long-segment fixations. Our study indicates that maximum improvement was noticed by 1 month and it was sustained until the final follow-up at 24 months. In other words, functional improvement is achieved within the first month post-procedure due to added stability without fear of failure.

Nagad et al. [5] reported 5 cases of post-vertebroplasty instability occurring at an average of 13 months (range, 8–17 months) after the procedure. They concluded that the long-term effects of cement on the augmented vertebral body and adjacent endplates contribute to this instability. Their study emphasized that while PVP provides mechanical stabilization, it does not promote bony union, allowing micromotion to persist for years. They hypothesized that postvertebroplasty instability results from the collapse of the surrounding osteoporotic bone and endplates around the cement mass.

Nakamae et al. [6] retrospectively reviewed 195 patients who underwent PVP for single-level OVCFs with intravertebral clefts. They found that 49 patients (25%) experienced cement loosening within 6 months post-PVP. Additionally, the mean VAS scores were significantly higher in patients who developed cement loosening compared to those who did not (p<0.01). The study also revealed a strong association between cement loosening and intravertebral instability, with an odds ratio of 1.20 (95% confidence interval, 1.04–1.40; p=0.015).

In contrast, our study demonstrated no cases of postsurgical instability or cement loosening at the final follow-up (24 months). We attribute this stability to the additional support provided by internal fixation, which likely compensates for the limitations observed with vertebroplasty alone.

Our study also identified 2 cases of post-PVP instability and cement loosening, both of which were successfully treated using the same minimally invasive short-segment percutaneous fixation with cement augmentation. This technique shows promise as a treatment option for addressing post-PVP failures. However, further studies with larger sample sizes are necessary to validate this approach and confirm its effectiveness.

The use of cement augmentation in osteoporotic bone is crucial for achieving sufficient screw purchase and stability. This study’s findings align with previous research demonstrating the effectiveness of cement augmentation in enhancing the biomechanical stability of pedicle screws in osteoporotic spines.

This study has several limitations, including its retrospective design, the relatively small sample size, and the midterm (24-month) follow-up. Additionally, the lack of a control group limits the ability to compare this technique with other surgical or conservative treatments for OVCF. Another limitation of the study is, we did not compare the kyphosis measurements achieved intraoperatively by prone positioning with that of at 24-month follow-up as we recorded the kyphosis directly at 24 months and compared with preoperative measurements. The comparison with intraoperative positional correction with follow-up points would have given important insight in how much correction is lost during follow-ups.

CONCLUSION

Minimally invasive short-segment cement-augmented percutaneous pedicle screw fixation without fusion demonstrated significant improvement in postoperative ODI and VAS scores, with maximum improvement observed at 1 month postoperatively and sustained through 24 months. This technique provides a minimally invasive option with clinically satisfactory outcomes for elderly patients with OVCF and intravertebral instability. Further studies with larger sample sizes and longer follow-up are warranted to confirm these findings.

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