O-Arm Accuracy and Radiation Exposure in Adult Deformity Surgery

Sacropelvic Fixation with Porous Fusion/Fixation Screws: A Technical Note and Retrospective Review

OBJECTIVE

The goal of this study was to analyze our initial experience using a novel porous fusion/fixation screw (PFFS) for pelvic fixation and determine our rate of screw malposition requiring intraoperative repositioning.

METHODS

We reviewed 83 consecutive patients who underwent sacropelvic fixation with PFFS at our institution from June 1, 2022 to June 30, 2023 using intraoperative computed tomography-based computer-assisted navigation via an open posterior approach. Following PFFS insertion, intraoperative computed tomography scans were obtained to assess screw positioning. Demographic data were collected, and operative reports and patient images were reviewed to determine what implants were used and if any PFFS required repositioning.

RESULTS

Seventy-four patients (26M:48F) were included, and 57 (77.0%) had a prior sacroiliac joint or lumbar spine surgery. A stacked screw configuration was used in 62/74 cases (83.8%). A total of 235 PFFS were used and six (2.6%) were malpositioned. Of 88 cephalic screws placed in stacked configuration, 4 were malpositioned (4.5%) and 1/123 caudal screws were malpositioned (0.8%). One of 24 sacral-alar-iliac screws placed in a stand-alone configuration was malpositioned (4.2%). Malpositions included 4 medial, 1 lateral, and 1 inferior, and all were revised intraoperatively without major sequela.

CONCLUSIONS

Although PFFSs are larger than traditional sacropelvic fixation screws, stacked sacral-alar-iliac instrumentation can be done safely with computer-assisted navigation. We found a low malposition rate in our initial series of patients, the majority being the cephalad screw in a stacked configuration. This isn't surprising, as these are placed after the caudal screws, which reduces the available corridor size and increases the placement difficulty.

New Spinal Shortening Technique for Tethered Cord Syndrome: A Technical Note

Background and Objectives: To present a new spinal shortening technique for tethered cord syndrome. Tethered cord syndrome (TCS) is a debilitating condition leading to progressive neurological decline. Surgical detethering for TCS is the gold standard of treatment. However, symptomatic retethering of TCS has been reported in 5%-50% of patients after initial release. To solve this problem, posterior spinal shortening osteotomy has been reported. This technique has risks of massive blood loss and neurological deterioration. The authors hereby report a new safe spinal shortening technique for tethered cord syndrome. Materials and Methods: A 31-year-old man with gait disturbance was referred to our hospital. After the delivery of treatment, he underwent surgical untethering of the spinal cord in another hospital. He had hyperreflexia of the Achilles tendon reflex and bilateral muscle weakness of the legs (MMT 3-4). He also had urinary and bowel incontinence, and total sensory loss below L5. An anteroposterior lumbar radiogram indicated partial laminectomy of L3 and L4. Lumbar MRI showed retethering of spinal cord. Results: The patient underwent a new spinal shortening technique for tethered cord syndrome under the guidance of O-arm navigation. First, from the anterior approach, disectomy from T12 to L3 was performed. Second, from the posterior approach, Ponte osteotomy was performed from T12 to L3, shortening the spinal column by 15 mm. The patient was successfully treated surgically. Postoperative lumbar MRI showed that the tension of the spinal cord was released. Manual muscle testing results and the sensory function of the left leg had recovered almost fully upon final follow-up at one year. Conclusions: A retethered spinal cord after initial untethering is difficult to treat. This new spinal shortening technique can represent another good option to release the tension of the spinal cord.

A C-Arm-Free Minimally Invasive Technique for Spinal Surgery: Cervical and Thoracic Spine

Background and Objectives: C-arm-free MIS techniques can offer significantly reduced rates of postoperative complications such as inadequate decompression, blood loss, and instrumentation misplacement. Another advantageous long-term aspect is the notably diminished exposure to radiation, which is known to cause malignant changes. This study emphasizes that, in some cases of spinal conditions that require a procedural intervention, C-arm-free MIS techniques hold stronger indications than open surgeries guided by image intensifiers. Materials and Methods: This study includes a retrospective analysis and review of various cervical and thoracic spinal procedures, performed in our hospital, applying C-arm-free techniques. The course of this study explains the basic steps of the procedures and demonstrates postoperative and intraoperative results. For anterior cervical surgery, we performed OPLL resection, while for posterior cervical surgery, we performed posterior fossa decompression for Chiari malformation, minimally invasive cervical pedicle screw fixation (MICEPS), and modified Goel technique with C1 lateral mass screw for atlantoaxial subluxation. Regarding the thoracic spine, we performed anterior correction for Lenke type 5 scoliosis and transdiscal screw fixation for diffuse idiopathic skeletal hyperostosis fractures. Results: C-arm-free techniques are safe procedures that provide precise and high-quality postoperative results by offering sufficient spine alignment and adequate decompression depending on the case. Navigation can offer significant assistance in the absence of normal anatomical landmarks, yet the surgeon should always appraise the quality of the information received from the software. Conclusions: Navigated C-arm-free techniques are safe and precise procedures implemented in the treatment of surgically demanding conditions. They can significantly increase accuracy while decreasing operative time. They represent the advancement in the field of spine surgery and are hailed as the future of the same.

O-Arm- and Guide-Device-Assisted Personalized Percutaneous Kyphoplasty for Thoracolumbar Osteoporotic Vertebral Compression Fractures

With the ageing of the global population, the incidence of osteoporotic vertebral compression fractures (OVCFs) is increasing. To assess the safety and efficacy of O-arm- and guide-device-assisted personalized percutaneous kyphoplasty (PKP) for treating thoracolumbar OVCFs, a total of 38 consecutive thoracolumbar OVCF patients who underwent bilateral PKP assisted with an O-arm and a guide device (O-GD group, n = 16) or traditional fluoroscopy (TF group, n = 22) from January 2020 to December 2021 were retrospectively reviewed, and their epidemiologic, clinical and radiological outcomes were analysed. The operation time was significantly decreased (p < 0.001) in the O-GD group (38.3 ± 12.2 min) compared with the TF group (57.2 ± 9.7 min). The number of intraoperative fluoroscopy exposures was significantly decreased (p < 0.001) in the O-GD group (31.9 ± 4.5) compared with the TF group (46.7 ± 7.2). Intraoperative blood loss was significantly decreased (p = 0.031) in the O-GD group (6.9 ± 2.5 mL) compared with the TF group (9.1 ± 3.3 mL). No significant difference (p = 0.854) in the volume of injected cement was observed between the O-GD group (6.8 ± 1.3 mL) and the TF group (6.7 ± 1.7 mL). Both the clinical and radiological outcomes, including the visual analogue scale score for pain, Oswestry Disability Index and anterior height and local kyphotic angle of the fractured vertebrae, were significantly improved at the postoperative and final follow-up but did not differ between the two groups. The incidence of cement leakage and refracture of the vertebral body was similar in the two groups (p = 0.272; p = 0.871). Our preliminary study demonstrated that O-GD-assisted PKP is a safe and effective procedure that presents a significantly shorter operation time, fewer intraoperative fluoroscopy exposures and less intraoperative blood loss than the TF technique.