TL spine fractures account for 75% of all spinal injuries. The majority of TL fractures manifest at a young age, at the levels of T11 to L2. The most common cause is motor vehicle accidents. However, osteoporosis increases the incidence of these fractures among the elderly people. [1] - [3] Although conservative treatment may be successful for certain TL fractures in cases without neurologic dysfunction, short-segment pedicle screw fixation has been demonstrated to be a more efficient method for restoring vertebral height, correcting kyphosis, &stabilizing fractures. [4] [5] The aim of the surgical intervention in these fractures is stabilization of the spine to restore the neurological function, protect the neural elements, prevent or correct collapse and kyphosis, and reestablish regular spinal mechanics. An agreement regarding the necessity of surgical decompression, fixation, &fusion for vertebral fractures accompanied by neurological deficiency, the surgical management of cases with vertebral fractures devoid of neurological disorder remains a subject of controversy. [6] - [9] Thoracic compression & burst fractures that are unstable (loss of anterior vertebral height greater than 50%, angular deformity greater than 20˚, & contiguous fractures) may progress to additional kyphosis. [6] [10] There exists certain evidence suggesting that those who chose to undergo surgery in these particular cases achieved superior clinical &radiological results compared to those who were treated non-operatively. [11] long-term follow-up revealed enhanced local kyphosis. [12]

Posterior fixation and instrumentation using open approaches is considered the classical surgical treatment of TL fractures. [6] The past decade has seen a steady advancement in minimally invasive posterior spine surgery. It is believed that minimally invasive procedures will induce less morbidity & yield comparable outcomes to conventional procedures. The percutaneous technique was originally used to treat degenerative spine diseases; Foley et al. documented the first case of degenerative spine disorder treated with percutaneous fixation in 2001, [13] while the first percutaneous fixation of spinal fracture was described by Assaker in 2004. Since then, Numerous publications have been published explaining the advantages &disadvantages of this method. [14] While the minimally invasive thoracolumbar fracture method does offer comparable benefits, the available evidence is primarily restricted to observational studies that utilize low-level & low-energy approaches. In addition, the available evidence for this method is further limited by its ineffectiveness over time in the treatment of TL spine fractures. [15]

This study was retrospectively conducted on forty-eight patients, ages ranging from 16 to 65 years old, with a thoracolumbar (TL) fracture without causing neurological impairments who were meeting the eligibility criteria for fixation in the period from July 2019 to January 2024. Patients were operated upon in Fayoum University hospitals, Bani Suef University hospitals and private hospitals. All patients were subjected to thorough history taking, neurological examination and routine investigations. Investigations included preoperative labs, also, radiological in the form of X-Ray spine, CT (Computed tomography) Dorso-lumbar spine and (Magnetic resonance imaging) Dorso-lumbar spine to assess the pathology in detail with good visualization of neural tissue, nerve roots, discs and facet joints.

We included the forty-eight patients who met the inclusion criteria (34 males and 14 females) their ages ranged from 16 to 65 years. The most common pathology was L1 fracture in 38 patients. According to the duration of surgery, it varied from 90 to 150 minutes. In our series, blood loss was less than 100 millilitres in 46 patients, while only 2 patients experienced blood loss of 150, 200 millilitres respectively. Regarding chronic post-operative low back pain, only eight patients, 17% experienced chronic post-operative low back pain in a six-month follow-up period with VAS scores ranging from 2 to 4 maximum. Despite the absence of noticeable variations in pain scores during long-term follow-up, early follow-ups revealed reduced VAS scores in comparison to preoperative pain. Regarding the hospital stay, patients were only admitted to the ward for a maximum of 72 hours with mean of 32 hours hospital stay. No major complications were encountered. According to infection rate, it appears that percutaneous fixation resulted in a reduced incidence of infection, only wound infection in five patients which was treated efficiently with repeated dressings and broad-spectrum antibiotics. In our study screw positioning was done using either with fluoroscopy-assisted pedicle screw placement or freehanded technique, utilizing the percutaneous technique, four patients (8%) experienced maldirected screws, only in one patient (2%) the screw encroached into the spinal canal with no deficit experienced while other three patients (6%) showed minimally laterally deviated screws.

Classic open technique has been associated with muscle atrophy due to muscle devascularisation & denervation induced by muscle separation, detachment, & continuous contraction [17] . This results in intraoperative haemorrhaging, necessitates blood transfusions, & elevates the risk of infection [18] . Muscle separation further results in post-operative pain &strength loss, both of which impede functional recovery & contribute to the progress of chronic pain. Chronic low back pain has been linked to multifidus muscle weakness as a pathophysiological factor. [19] [20] . Reduced tissue dissection is the primary benefit of percutaneous fixation for vertebral fractures. Regev et al. demonstrated that the motor nerve of the multifidus muscle was damaged in as many as eighty percent of cases undergoing open procedures, whereas the percentage was only 20% in cases who underwent percutaneous procedures. [21] By avoiding damage to the paravertebral musculature, percutaneous surgery restricts bleeding, decreases infection rates, & decreases post-operative pain. In our study, only eight patients, 17% experienced weak paravertebral muscles and chronic post-operative low back pain in a six-month follow-up period. These benefits could potentially shorten the duration of hospitalization, accelerate rehabilitation, &, in theory, prevent long-term failure of adjacent segments. Preserving muscle innervation would also reduce muscle atrophy & scarring, as demonstrated by MRI & post-operative muscle enzyme dose. [22] Jiang et al. discovered that the percutaneous group had superior function & lower pain scores than the open cohort, the same finding as other studies. [22] Lee et al., on the contrary, discovered little variance among the percutaneous & open fixation groups in terms of VAS scores. [23] Likewise, a current meta-analysis found no variance among the 2 techniques regarding pain during the medium-term follow-up period. [24] This may be accounted for by the increased heterogeneity among the variance researchers. Despite the absence of noticeable variations in pain scores during long-term follow-up, early follow-ups (three months) revealed reduced VAS scores following percutaneous fixation. This improvement in spinal stability led to earlier mobilization of the patient. [25] - [28] By facilitating earlier ambulation, cases can reduce their risk of developing complications related to bed rest & ulcers. [22] [24] By achieving this, the average length of hospitalisation for patients in our study was reduced by 5.72 days, which translates to substantial savings of hospitalisation expenses, involving the cost associated with the osteosynthesis material and this was matching results from several published studies. [29] [30] Tromme et al. assessed over a thousand percutaneously inserted screws for fractures & discovered a number of intriguing results15% of the cases involved moderate breaching of the facets, while a mere 0.6% of the cases involved serious damage [30] . Moreover, regarding intraoperative blood loss percutaneous fixation reduces both haemorrhaging & operative duration. In our series, blood loss was less than 100 millilitres in 46 patients, while only 2 patients experienced blood loss of 150, 200 millilitres respectively. Many researchers demonstrated that percutaneous fixation resulted in less blood loss than standard open fixation. The percutaneous technique resulted in fifty millilitres less blood loss (range: 200 - 500 mL) than the open group, as determined by Merom et al. Blood loss was significantly reduced in 32 additional patients who underwent the minimally invasive procedure. [31] Upon aggregating these findings into a meta-analysis, it was determined that percutaneous fixation substantially decreased surgical bleeding by 285.44 mL. [25] [26] Similar to the previous results, Wild et al. observed a statistically significant reduction in blood loss among trauma patients subsequent to percutaneous implantation of the Dick et al. internal fixation system as opposed to open procedure implantation [32] . Schmidt et al. documented a sequence of 76 cases involving percutaneous long-segment fixation of the thoracic spine. Only three cases required blood transfusion; in each of these cases, an additional anterior procedure was also required. [33] . Surgical duration is highly dependent on the experience of the operating surgeons. Our study lasted from 90 to 150 minutes. Initial reports failed to distinguish among the two methods. Current publications, however, indicate that operative times are shorter when compared to open techniques, a finding that operating surgeons have assimilated since their learning curve. [23] [25] According to a study by Merom et al. [31] , the operative time for percutaneous fixation (73 to 85 min) was slightly lower than that of open fixation (78 to 102 min) when short-segment fixation was utilized. An average operative time of 70 min was documented by Ni et al. [34] for short-segment fixation. The average operative time in a series of 76 cases (16 with long-segment fixation) was 47 min, according to Schmidt et al. The total operative time for 56% of these patients was among 22 & 36 min [33] . According to infection rate, it appears that percutaneous fixation results in a reduced incidence of infection in comparison to open fixation. In our study, only superficial wound infection in five patients was treated efficiently with repeated dressings and broad-spectrum antibiotics. Schmidt et al. conducted a series of 74 patients undergoing percutaneous fixation & didn’t find any infections (n = 74). In contrast, Ni et al. identified 1 infection in 36 cases (2.7%). [33] [34] When open fixation is carried out on trauma cases, these infection rates are slightly lower than the known infection rate. Phan et al. conducted a meta-analysis which revealed that the percutaneous fixation group had significantly lower infection rates than the open fixation group (0.3% vs 3.4%, respectively; relative risk (RR) = 0.36). [35] Out of the 36 cases who underwent percutaneous fixation, Ni et al. documented only one superficial infection that was only managed with antibiotics [34] . Schmidt et al. observed no infections in 76 patients; however, they carried out one revision in the case of a paravertebral hematoma [33] . Merom et al. [31] found no infections in ten instances of percutaneous fixation & only one superficial infection in ten instances of open fixation. One infection necessitated the removal of instrumentation in one of 64 percutaneous fixation cases reported by Palmisani et al. [36] . In comparison to infection rates for open procedures, which range from approximately 3.1% to 10%, the total infection rate documented in these published research findings was comparatively modest [37] . Individuals who underwent percutaneous fixation in the Merom et al. study were capable of ambulating within one to two days following the operation, whereas those who underwent open fixation were required to wait 3 to 4 days [31] . Prior to percutaneous surgery for trauma indications, some patients documented shorter hospitalizations [31] [38] . Better screw positioning correlates with fluoroscopy-controlled pedicle screw placement as opposed to the freehand technique. Utilizing the percutaneous technique in our study, four patients (8%) experienced misdirected screws, only in one patient (2%) the screw encroach into the spinal canal with no deficit experienced, while the other three patients (6%) showed minimal laterally deviated screws. Rangel identified a mere 3% of improperly placed screws. In contrast, Ni et al. detected 6.7% of screw misplacements generally, all of which didn’t involve neurological involvement. [34] Despite this, one meta-analysis found no significant variance among percutaneous fixation (4.0%) and open fixation (4.2%) with regard to screw malpositioning. [34] It is noteworthy that the method of open freehand has a tendency to misposition the screw medially, while fluoroscopy reveals that the mispositioned screw is more likely to occur in the “safer” lateral zone. [38]

The advantages of percutaneous pedicle screw fixation in thoracolumbar fractures through preservation of posterior musculature are less blood loss, shorter operative time, lower infection risk, less post-operative pain, shorter rehabilitation time as well as shorter hospital stay. Limitations of percutaneous fixation include the inability to achieve direct spinal canal decompression and not having the option to perform a fusion and also requiring a learning curve to masterize the anatomy and technique.