Minimally invasive treatment of pedicle stress fracture in a young athlete: A case report

Abstract

Introduction

Pedicle stress fractures are an uncommon type of non-union often associated with contralateral neural arch interruption in young, active patients. Patients present with long-lasting low back pain, and the diagnosis is usually delayed. Treatment is generally conservative. Few cases treated surgically are described in the literature, with a high degree of treatment heterogeneity and no consensus on optimal treatment.

Presentation of case

A 24-year-old male, following a sports-related trauma, developed persistent lower back pain. Imaging revealed a right L3 pedicle stress fracture with left lamina and pars interarticularis interruption. A minimally invasive percutaneous approach targeting the pedicle fracture was chosen. The procedure aimed to alleviate pain and promote non-union healing, without addressing the contralateral defect. The patient quickly recovered, achieving significant pain relief, and starting a tailored physical therapy program. At the 4-month follow-up, the pedicle fracture healed with callus formation. The patient returned to sports practice.

Discussion

Pedicle stress fractures may result from biomechanical force redistribution. Diagnosis is challenging, necessitating advanced imaging, including bone scintigraphy, MRI, and CT scans. Conservative management with rest, restriction with a brace, and focused rehabilitation usually achieves good results. When conservative management fails, surgery should be considered. Surgical options include direct repair, bone grafting, and screw fixation of the pedicle and contralateral pars defect.

Conclusion

Minimally invasive surgery can achieve good clinical and functional results while avoiding blood loss and soft tissue trauma. Treating only the stress fracture is sufficient to promote bone healing, in contrast to more complex procedures.

Highlights

• •Pedicle stress fracture can be a source of chronic pain in the young athlete.
• •Pedicle stress fracture is often associated with contralateral posterior defects including spondylolysis or lamina fracture.
• •Conservative treatment usually provides good clinical results.
• •A single minimally invasive screw in pedicle stress fractures provides enough stability to promote healing.

1. Introduction

Pedicle stress fractures are a rare cause of lower back pain usually affecting young athletic individuals, with only a few cases described in the literature. These fractures are typically accompanied by contralateral neural arch interruption. Other unusual causes of pedicular stress fractures have been reported including posterolateral lumbar fusion, laminectomy, and surgery for thoracolumbar scoliosis [[1], [2], [3]].

Pedicle stress fractures most commonly affect the lumbar spine in young athletic patients, resulting in persistent lumbar pain. The exact etiology of these fractures is not fully understood but is believed to involve stress force redistribution and can be associated with contralateral isthmic spondylolysis [4]. Diagnosis of pedicle stress fractures can be challenging, with plain radiographs having limited sensitivity. However, MRI, CT, and SPECT are valuable imaging modalities for detection and evaluation [5,6]. Treatment strategies for pedicle stress fractures vary, and conservative management has shown success in many cases. This approach typically includes activity restriction, immobilization with braces, and comprehensive physical therapy program [4,[6], [7], [8], [9], [10]].

In this report, we present a rare case of a young patient with lumbar pedicle stress fracture associated contralateral neural arch interruption requiring surgical treatment. A simple minimally invasive percutaneous procedure was performed at our academic tertiary hospital with good clinical outcome. This case has been reported in line with the SCARE criteria [11].

2. Presentation of case

A 24-year-old male presented with persistent back pain for 2 years after a sports injury resulting in a right tibial plateau fracture. He developed localized low-intensity pain on the right side of his lower back. On clinical examination the patient presented localized pain during lumbar spine palpation. Anterior flexion of the spine was painful but complete. CT showed hypertrophic non-union of the right L3 pedicle (Fig. 1A) with an associated left L3 lamina and pars interarticularis interruption (Fig. 2). The MRI showed abnormal fluid signal consistent with edema within the right L3 pedicle (Fig. 3). Technetium-99m bone scan showed diffuse metabolic activity in the right L3 hemisome (Fig. 4). Blood results revealed normal levels of inflammatory markers, calcium, vitamin D, phosphate, LDH and parathyroid hormone without any other significant anomaly in routine tests.

Fig. 1.

Axial and sagittal images of the L3 vertebra: (A) before treatment, highlighting the pedicle and lamina fractures (B) after treatment, and (C) after 4 months of follow-up, with healing of the right L3 pedicle.

Fig. 2.

CT images of the L3 vertebra showing involvement of the posterior elements, left lamina fracture and pars interarticularis interruption.

Fig. 3.

MRI sagittal and axial images showing bone marrow edema in the right L3 pedicle suggestive of stress fracture.

Fig. 4.

Anterior and posterior whole body 99mTc MDP bone scan planar images demonstrate focal uptake localizing to the right L3 hemisome.

Consensus opinion from our group of spine surgeons was sought due to patient's young age and the rarity of this condition. A decision was made to perform a minimally invasive X-ray guided L3 right pedicle fixation. The goal of this surgery was to remove pain and allow non-union healing providing stability. Under general anesthesia, with patient in prone position, an incision was made via a Wiltse approach. Fluoroscopy-guided placement of an awl in the right L3 pedicle was confirmed, followed by K-wire insertion. A fully threaded titanium cannulated 45 mm × 6.5 mm modular pedicle screw without tulip, PRECEPT® (NuVasive, San Diego, CA, USA), was inserted percutaneously. The procedure lasted approximately 30 min and was performed by an operator with more than 10 years of experience in spine surgery. The patient was able to stand, bearing full weight right after recovering from anesthesia thus VTE prophylaxis was not administrated. Symptoms improved early post-surgery, with CT confirming correct screw positioning and gap reduction at the non-union site (Fig. 3B). The patient was discharged after 2 days with complete pain resolution.

After discharge, the patient initiated a physical therapy program specifically targeting postural re-education. Five weeks later, the patient was pain-free and able to work. Standing full-spine radiographs showed correct screw positioning without loosening (Fig. 5). A more intense rehabilitation program aimed to core muscles strengthening was started. The CT scan after 4 months showed healing of the L3 pedicle fracture with stable left lamina and pars defect (Fig. 3C). The patient was cleared to return to sport practice.

Fig. 5.

Coronal and sagittal standing full-spine X-rays after 5 weeks of follow-up.

3. Discussion

Pedicle stress fractures are rare and occur mainly in the lumbar spine at the L2–L5 levels in young athletic individuals causing persistent pain. Stress fractures may result from an abnormal redistribution of forces in the spine. For example, biomechanical studies have demonstrated that unilateral spondylolysis could lead to stress fracture at the contralateral pedicle due to repetitive overload. The increased instability produces compensatory hypertrophy and sclerosis of the pedicle [4]. Gunzburg et al. introduced the term “pediculolysis” to describe the characteristics of this type of fracture [12]. In the case presented, the history of traumatic episode creates uncertainty about the origin of the stress fracture. Both pedicle and contralateral fractures could be the result of the single traumatic event. Analogously, the presence of an asymptomatic pre-existing unilateral isthmic spondylolysis cannot be excluded either. Whatever is the origin of the pedicle stress fracture it acts in this case as an area of pseudarthrosis.

The diagnosis of pedicle stress fracture may be challenging, and achieving an early diagnosis is difficult. Plain radiographs can be used as first-line investigation but have a poor sensibility for detection of stress fractures. Bone scintigraphy and MRI are the two best method to detect a stress injury. MRI provides useful information by demonstrating inflammatory changes. Bone scintigraphy and SPECT bone imaging are useful when MRI in inconclusive and to exclude pathologies of other nature. CT scan provides excellent definition of the bony anatomy and aids in treatment planning.

Different treatment strategy for pedicle stress fracture have been proposed. In many cases a conservative approach based on activity restriction and immobilization with braces has been successfully used [4,[7], [8], [9], [10]]. Kessous et al. [5] reported a case of a 16-year-old patient with a unilateral pedicular stress fracture and contralateral spondylolysis who was successfully treated with a Boston brace for 6 weeks, bone stimulator, activity modification, and physical therapy, resulting in healing of the pedicle fracture and a stable pars defect. Vialle et al. [9] presented a case of a 12-year-old boy treated with full-time brace, which led to complete healing of the pedicle fracture, advocating for conservative treatment in skeletally immature patients. Interestingly, a good clinical outcome was achieved in several cases, including the present study, without requiring bony union of the pars defect (Fig. 3C). In 2021 a narrative review by Vaccaro et al. [6] summarized different diagnostic and rehabilitation protocols for acute lumbar stress reactions in athletes.

In rare cases where conservative management fails, surgical intervention may be considered. Surgical treatment could represent an option after failing of a proper rehabilitation program for 6–12 months [6]. Considering the rarity of the condition and the limited literature a carful case-based evaluation is warranted. Surgical options include direct repair, bone grafting, and screw fixation of the pedicle and contralateral pars defect. In in 1986, one of the first surgical treatments was proposed by Garber et al. [13] for a young patient with L4 right pedicle sclerosis and a left pars interarticularis defect. The treatment involved bone grafting the right pedicle after drilling and fixing the pars interarticularis defect using the Scott procedure, a wiring technique to provide internal fixation after Gill procedure and bone grafting. Weatherley et al. [14] reported a successful case of direct repair with screws in a 26-year-old athlete with a lumbar pedicle fracture and contralateral spondylolysis. With an open approach, the pedicle fracture was treated with a screw while the contralateral pars defect was repaired using the Buck technique achieving compression in both lesion sites. Nakayama et al. [15] utilized bilateral pedicle screws connected with a U-shaped rod for the treatment of a 20-year-old baseball player with pedicle fractures. Bone grafts harvested from posterior iliac crest combined with artificial bone were placed on the pars defect. In this case the authors were concerned about repetitive mechanical stress in a young and very active patient and therefore they chose a stronger construct. A more aggressive approach was implemented by Viswanathan et al. [16] on a 41-year-old woman with low back and left-sided radicular pain affected by L4 pediculolysis, contralateral Spondylolysis and grade 1 spondylolisthesis and instability found on dynamic lateral radiographs. An L5-S1 arthrodesis was performed. A subsequent extension to L4 and L5 pediculectomy was necessary advocating for a more aggressive surgery when radicular symptoms and degenerative condition coexist with the pedicle fracture. More recently, Kögl et al. [17] implemented a minimally invasive navigated approach for an acute L5 bilateral fracture in a 49-year-old man. The pedicle stabilization was accomplished with the off-label use of traction screws to achieve compression of the fracture site. The same strategy was employed by Johnson et al. [18] on a spontaneous bilateral lumbar pedicle fracture in a 50-year-old woman. In this case the authors chose to use cannulated pedicle screws realizing compression through lag screw technique.

In our presented case, a young patient with persistent and well localized back pain due to a stress fracture in the right L3 pedicle and contralateral neural arch defect underwent surgical treatment. We decided to focus only on the pain source and opted for direct stabilization of the pedicle stress fracture. This targeted surgical intervention aimed to modify the mechanical environment at the fracture site, reducing strain and stimulating bone healing. Similarly, to other cases treated percutaneously bone grafting was not considered essential, saving the patient from additional operative time and donor site morbidity. In contrast to other minimally invasive operative cases, we utilized a spine certified pedicle screw without tulip and compression was not applied as we believed improving stability was sufficient to promote healing. The contralateral lamina and pars defect were left untreated based on favourable outcomes observed in conservatively managed cases, where the contralateral neural arch defect remained unhealed even after the pedicle fracture had healed. By adopting a minimally invasive approach, we minimized blood loss and soft tissue trauma, our patient experienced a rapid rehabilitation process and was able to resume full sports activities within four months of treatment.

4. Conclusion

Minimally invasive surgical techniques addressing only the pedicle stress fracture can be effective in promoting bone healing and facilitating early recovery. A multidisciplinary approach involving spine surgeons, radiologists, and physical therapists is essential for effectively managing patients with pedicle stress fractures and achieving optimal outcomes.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

Not applicable.

Funding

"5x1000 grant" - year 2020 from Italian Ministery of Health.

Author contribution

Riccardo Germandi: Conceptualization, Investigation, Writing - Review & Editing, Supervision. Luigi Falzetti: Writing - Original Draft, Visualization Dario Haddad: Writing - Original Draft, Visualization Valerio Pipola: Writing - Review & Editing, Investigation Alessandro Gasbarrini: Conceptualization, Writing - Review & Editing, Supervision.

Guarantor

Riccardo Germandi and Alessandro Gasbarrini.

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Conflict of interest statement

The authors declare that they have no competing interests.

Data availability

The data used to support the findings of this study are available from the corresponding author upon reasonable request.