The thoracolumbar spine is the most common site of spinal fractures, but approximately two-thirds to three-quarters of vertebral fractures are clinically undetected (1). A lack of or inappropriate treatment may lead to a progressive collapse of the fractured vertebrae, resulting in local kyphosis, especially in patients with osteoporotic vertebral compression fractures. As the kyphosis progresses, patients may present with intractable thoracolumbar pain, lower limb weakness, urinary and bowel dysfunction, dyspnea, abdominal distension and pain, and other nerve or chest and abdominal organ compression symptoms, which may also cause serious mental health problems. Patients typically seek further treatment to relieve pain and improve the quality of life (12).

Vertebral compression fractures are the most common osteoporotic fractures and are frequently under-recognized, with only a minority being clinically diagnosed (3, 4). Inadequately treated or progressive fractures may lead to vertebral height loss and segmental hyperkyphosis, which is associated with persistent pain, impaired activities of daily living, reduced quality of life, and increased healthcare utilization (4, 5). Hyperkyphosis may also reduce thoracic volume and pulmonary function, contributing to broader functional decline (6). Therefore, for patients with long-standing osteoporotic vertebral compression fractures complicated by fixed thoracolumbar kyphosis and disabling symptoms, surgical correction is often required to relieve symptoms, restore sagittal alignment, and improve function (7, 8).

Since Smith‒Petersen et al. (9) first reported the use of Smith‒Petersen osteotomy (SPO) for the treatment of thoracolumbar kyphosis caused by ankylosing spondylitis, remarkable progress has been made in the treatment of kyphosis because of improvements in imaging and surgical instruments and rapid developments in spinal osteotomy techniques. Chang et al. (10) classified spinal osteotomies into open-wedge osteotomy, closing-wedge osteotomy, and closing‒opening wedge osteotomy. Schwab et al. (11) summarized and classified spinal osteotomy techniques on this basis, including classes such as partial facet joint resection, complete facet joint resection, pedicle and partial body resection, pedicle, partial body, and disc resection; complete vertebra and disc resection; and multiple adjacent vertebrae and disc resection. In clinical applications, the correction achieved at each stage is approximately 10° per classification. If a greater osteotomy angle is needed, a combined multistage osteotomy procedure can be performed.

In clinical practice, the choice of osteotomy depends on deformity rigidity, required correction angle, and patient-specific risk factors. SPO and Ponte osteotomy are commonly used for flexible deformities requiring modest correction, whereas PSO provides larger angular correction but is associated with longer operative time and substantial blood loss. For severe, rigid angular kyphosis, vertebral column resection can achieve powerful correction but carries a high complication burden.

Importantly, these procedures are often performed in elderly patients with osteoporosis, in whom reduced bone quality increases the risks of screw loosening, fixation failure, non-union, and revision surgery, while extensive osteotomy surfaces may further increase bleeding and perioperative morbidity. Therefore, optimizing corrective osteotomy strategies to balance correction efficacy and perioperative safety remains a key clinical challenge in osteoporotic populations.

Despite advances in deformity correction, perioperative morbidity and mechanical complications remain substantial, particularly in osteoporotic patients who are vulnerable to fixation failure and delayed fusion. Therefore, there is a clinical need for an osteotomy strategy that can provide sufficient correction, while minimizing operative time, blood loss, and complication risk in this population. To address this gap, we developed a novel technique—transpedicular lower vertebral space osteotomy—and performed a retrospective comparison with PSO conducted by the same surgical team. This study aimed to evaluate the radiographic correction, functional recovery, and perioperative safety of transpedicular lower vertebral space osteotomy in patients with thoracolumbar kyphosis secondary to long-standing osteoporotic vertebral compression fractures.

Osteoporosis is defined as a BMD that is at least 2.5 SD below the average of that of healthy young women (T score < −2.5 SD). A systematic review and meta-analysis revealed a global prevalence of osteoporosis of 21.7% (13, 14). Osteoporosis is characterized by low bone mass and degeneration of the bone microstructure, which can significantly affect the progression of thoracolumbar vertebral deformity after fracture and bone fusion following surgery (15). In most cases, thoracolumbar vertebral fractures due to osteoporosis are caused by common daily movements (such as coughing and lifting light objects) or mild trauma (such as vehicle bumps and external impacts). These injuries are usually not treated promptly or are improperly treated (such as via massage, acupuncture, and premature weight-bearing activities), resulting in continued collapse of the fractured vertebral bodies and subsequent spinal kyphosis (16, 17).

Because adult spine curves are relatively stiff, spinal deformity in these patients typically manifests as thoracolumbar pain and neurological symptoms (18). Advances in surgical techniques have improved treatment outcomes. Schwab et al. (11) classified posterior spinal osteotomy into six levels based on previous research, among which SPO and PSO were more widely used. SPO was initially used primarily for ankylosing spondylitis, but its indications gradually expanded to include flat back syndrome and idiopathic scoliosis, and it was also used as a supplementary method for other osteotomies. Its advantages include less surgical trauma and lower risk, but the correction angle is small, and it is unsuitable for patients with moderate-to-severe sagittal plane deformities (>12 cm) (19, 20). PSO involves wedge resection of the vertebral arch and closure of the osteotomy surface using the anterior cortical bone as a hinge, which generally achieves a correction of approximately 30°–35°. It is primarily used for mild to moderate thoracolumbar kyphosis/lateral curvature deformities. Its advantages include not extending the anterior column, thereby avoiding nerve and vascular traction injury. However, the bone incision surface is larger, and the surgery time is prolonged, resulting in increased bleeding. In addition, there is a risk of torsional injury to the spinal cord due to excessive shortening of the posterior column (21).

Spinal kyphosis deformities often involve both coronal and sagittal plane abnormalities, and the corrected spine is subjected to significant deformation stress. In addition, elderly patients frequently have osteoporosis because of a lack of red bone marrow and bone metabolism disorders (22). Therefore, revision after surgical failure is not uncommon and is most frequent in cases of pseudojoint formation (i.e., bone fusion failure) (23). The use of recombinant human bone morphogenetic protein-2 has been shown to reduce the incidence of pseudojoints without increasing the risk of other complications (24). Progression of the kyphosis (curve) is another important cause of postoperative revision. Risk factors include injury to the posterior ligament complex, excessive orthosis, and long segmental fixation and fusion. The addition of transverse process hooks or vertebroplasty can reduce the incidence of proximal junctional kyphosis (25, 26). However, not all failures require surgical intervention, and the need for revision surgery should be determined based on symptoms and later progression.

In this study, it was found that there was no significant difference in the orthopedic outcomes between the PSO and the transpedicular lower vertebral space osteotomy groups. This may be related to the lack of extensive bone grafting or an interbody fusion apparatus in the latter, which can be used to maintain vertebral height and spinal cord tension in cases of angular kyphosis and other conditions. Both methods achieved satisfactory radiographic correction and clinical improvement; however, transpedicular lower vertebral space osteotomy was associated with a significantly shorter operative time and less blood loss, while the overall complication rate was numerically lower but did not reach statistical significance in this small cohort (Fisher's exact test, P = 0.090).

Previous studies have consistently shown that PSO, although effective for correcting rigid sagittal deformity, is associated with substantial perioperative morbidity. In a dedicated analysis of perioperative complications related to PSO, Daubs et al. reported a notable complication burden, highlighting the importance of minimizing operative time and blood loss when operating on older or medically fragile patients (27). Moreover, broader reviews focusing on complex adult spinal deformity procedures have also indicated that three-column osteotomies are accompanied by higher complication rates and greater blood loss than less invasive corrective strategies (28). In the specific setting of kyphosis following osteoporotic vertebral compression fractures, PSO-based strategies have been reported to require relatively long operative times and considerable blood loss in some series, reinforcing the rationale for exploring lower-trauma osteotomy options in osteoporotic populations (29, 30).

The extent of transpedicular lower vertebral space osteotomy includes the intervertebral discs and adjacent vertebrae and can be classified as type IV (20). This new osteotomy technique has the following advantages: (a) Preservation of the pedicle of the injured vertebra, which helps disperse stress and reduces the possibility of loosening or fracture of the internal fixation (31). (b) Destruction of the endplate can lead to a degeneration of adjacent intervertebral discs; disc removal can prevent progression of kyphosis to some extent (32, 33). (c) Ability to maintain the height of the intervertebral space following completion of the osteotomy via insertion of an interbody fusion device or bone grafting to avoid spinal cord distortion and injury. (d) Greater ease and speed, and the induction of less trauma compared with PSO. In addition, this procedure can be applied to degenerative kyphosis or infective kyphosis. For severe rigid angular kyphosis, the vertebral column resection can provide a powerful correction but has been associated with a higher overall complication rate than PSO in pooled analyses (34).

Although the new osteotomy proposed in this study aims to optimize the surgical method for correcting thoracolumbar kyphotic deformity and preliminarily confirms its effectiveness and safety, we are also clearly aware of its limitations. First, at the biomechanical level, similar to PSO, correcting the sagittal imbalance may induce or aggravate the coronal imbalance. Furthermore, in the thoracolumbar segment, the Adamkiewicz artery, originating from the root artery, is the primary nutrient vessel for the anterior spinal artery. During removal of the inferior vertebral wall, there is a risk of injury to this vessel, which may lead to catastrophic ischemic spinal cord injury. In this study, the average correction angle of transpedicular lower vertebral space osteotomy was 32.7° ± 7.3° and can be used in patients with non-ankylosing spondylitis and kyphosis Cobb angles less than 60°. We can also consider using it as a complementary operation alongside other osteotomy types, which would require further research and demonstration.

This study has several limitations. First, the retrospective, non-randomized, single-center design introduces potential selection bias, and unmeasured confounders (e.g., comorbidities, baseline frailty, and surgeon/patient preferences) may have influenced both procedure selection and outcomes. Second, the sample size was small (11 vs. 16), which may have limited statistical power and increased the risk of type II error; several baseline variables approached statistical significance (e.g., preoperative Cobb angle and ODI), and non-significant findings should therefore be interpreted cautiously. Third, follow-up intervals were not standardized, and “final follow-up” corresponded to the last available visit, which may limit the ability to draw firm conclusions about long-term mechanical complications (e.g., instrumentation loosening or recurrent kyphosis). Fourth, although we applied appropriate distribution-aware statistics and correction for multiple comparisons, repeated-measure assessment was limited by the availability of only a small number of time points. Finally, the learning curve of transpedicular lower vertebral space osteotomy was not formally evaluated; outcomes may vary with surgeon experience, and further multicenter studies are required to validate generalizability. In addition, detailed perioperative technical parameters (e.g., cement volume per screw) and comprehensive antiosteoporosis medication regimens were not uniformly recorded in the medical charts, which limited more granular analyses of their potential impact on outcomes.

Our results show that, compared with PSO, transpedicular lower vertebral space osteotomy is easier and faster to perform, with shorter operative time and lower blood loss, and yields comparable radiographic correction and clinical outcomes at the last available follow-up. At this time, however, the results cannot be fully confirmed, and definitive recommendations for the use of transpedicular lower vertebral space osteotomies cannot be made until additional studies with larger patient populations are conducted.