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Peng-Yuan Chang and Michael Y. Wang

In minimally invasive spinal fusion surgery, transforaminal lumbar (sacral) interbody fusion (TLIF) is one of the most common procedures that provides both anterior and posterior column support without retraction or violation to the neural structure. Direct and indirect decompression can be done through this single approach. Preoperative plain radiographs and MR scan should be carefully evaluated. This video demonstrates a standard approach for how to perform a minimally invasive transforaminal lumbosacral interbody fusion.

The video can be found here: https://youtu.be/bhEeafKJ370.

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Michael Y. Wang, Peng-Yuan Chang, and Jay Grossman

OBJECTIVE

Over the past decade, Enhancing Recovery After Surgery (ERAS) programs have been implemented throughout the world across multiple surgical disciplines. However, to date no spinal surgery equivalent has been described. In this report the authors review the development and implementation of a “fast track” surgical approach for lumbar fusion.

METHODS

The first 42 consecutive cases in which patients were treated with the new surgical procedure were reviewed. A combination of endoscopic decompression, expandable cage deployment, and percutaneous screw placement were performed with liposomal bupivacaine anesthesia to allow the surgery to be performed without general endotracheal anesthesia.

RESULTS

In all cases the surgical procedure was performed successfully without conversion to an open operation. The patients' mean age (± SD) was 66.1 ± 11.7 years, the male/female ratio was 20:22, and a total of 47 levels were treated. The mean operative time was 94.6 ± 22.4 minutes, the mean intraoperative blood loss was 66 ± 30 ml, and the mean hospital length of stay was 1.29 ± 0.9 nights. Early follow-up showed a significant improvement in the mean Oswestry Disability Index score (from 40 ± 13 to 17 ± 11, p = 0.0001). Return to the operating room was required in 2 cases due to infection and in 1 case due to cage displacement. An iterative quality improvement program demonstrated areas of improvement, including steps to minimize infection, improve postoperative analgesia, and reduce cage osteolysis.

CONCLUSIONS

ERAS programs for improving spinal fusion surgery are possible and necessary. This report demonstrates a first foray to apply these principles through 1) a patient-focused approach, 2) reducing the stress of the operation, and 3) an iterative improvement process.

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Peng-Yuan Chang, Hsuan-Kan Chang, and Jau-Ching Wu

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Hsuan-Kan Chang, Chih-Chang Chang, Tsung-Hsi Tu, Jau-Ching Wu, Wen-Cheng Huang, Li-Yu Fay, Peng-Yuan Chang, Ching-Lan Wu, and Henrich Cheng

OBJECTIVE

Many reports have successfully demonstrated that cervical disc arthroplasty (CDA) can preserve range of motion after 1- or 2-level discectomy. However, few studies have addressed the extent of changes in segmental mobility after CDA or their clinical correlations.

METHODS

Data from consecutive patients who underwent 1-level CDA were retrospectively reviewed. Indications for surgery were medically intractable degenerative disc disease and spondylosis. Clinical outcomes, including visual analog scale (VAS)–measured neck and arm pain, Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) scores, were analyzed. Radiographic outcomes, including C2–7 Cobb angle, the difference between pre- and postoperative C2–7 Cobb angle (ΔC2–7 Cobb angle), sagittal vertical axis (SVA), the difference between pre- and postoperative SVA (ΔSVA), segmental range of motion (ROM), and the difference between pre- and postoperative ROM (ΔROM), were assessed for their association with clinical outcomes. All patients underwent CT scanning, by which the presence and severity of heterotopic ossification (HO) were determined during the follow-up.

RESULTS

A total of 50 patients (mean age 45.6 ± 9.33 years) underwent a 1-level CDA (Prestige LP disc) and were followed up for a mean duration of 27.7 ± 8.76 months. All clinical outcomes, including VAS, NDI, and JOA scores, improved significantly after surgery. Preoperative and postoperative ROM values were similar (mean 9.5° vs 9.0°, p > 0.05) at each indexed level. The mean changes in segmental mobility (ΔROM) were −0.5° ± 6.13°. Patients with increased segmental mobility after surgery (ΔROM > 0°) had a lower incidence of HO and HO that was less severe (p = 0.048) than those whose ΔROM was < 0°. Segmental mobility (ROM) was significantly lower in patients with higher HO grade (p = 0.012), but it did not affect the clinical outcomes. The preoperative and postoperative C2–7 Cobb angles and SVA remained similar. The postoperative C2–7 Cobb angles, SVA, ΔC2–7 Cobb angles, and ΔSVA were not correlated to clinical outcomes after CDA.

CONCLUSIONS

Segmental mobility (as reflected by the mean ROM) and overall cervical alignment (i.e., mean SVA and C2–7 Cobb angle) had no significant impact on clinical outcomes after 1-level CDA. Patients with increased segmental mobility (ΔROM > 0°) had significantly less HO and similarly improved clinical outcomes than those with decreased segmental mobility (ΔROM < 0°).

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Quan-chang Tan, Jian-wei Wu, Fei Peng, Yuan Zang, Yang Li, Xiong Zhao, Wei Lei, and Zi-xiang Wu

OBJECTIVE

This study investigated the optimum injection volume of polymethylmethacrylate (PMMA) to augment a novel fenestrated pedicle screw (FPS) with diameter-tapered perforations in the osteoporotic vertebral body, and how the distribution characteristics of PMMA affect the biomechanical performance of this screw.

METHODS

Two types of FPSs were designed (FPS-A, composed of 6 perforations with an equal diameter of 1.2 mm; and FPS-B, composed of 6 perforations each with a tapered diameter of 1.5 mm, 1.2 mm, and 0.9 mm from tip to head. Each of 28 human cadaveric osteoporotic vertebrae were randomly assigned to 1 of 7 groups: FPS-A1.0: FPS-A+1.0 ml PMMA; FPS-A1.5: FPS-A+1.5 ml PMMA; FPS-A2.0: FPS-A+2.0 ml PMMA; FPS-B1.0: FPS-B+1.0 ml PMMA; FPS-B1.5: FPS-B+1.5 ml PMMA; FPS-B2.0: FPS-B+2.0 ml PMMA; and conventional pedicle screws (CPSs) without PMMA. After the augmentation, 3D CT was performed to assess the cement distribution characteristics and the cement leakage rate. Axial pullout tests were performed to compare the maximum pullout force thereafter.

RESULTS

The CT construction images showed that PMMA bone cement formed a conical mass around FPS-A and a cylindrical mass around FPS-B. When the injection volume was increased from 1.0 ml to 2.0 ml, the distribution region of the PMMA cement was enlarged, the PMMA was distributed more posteriorly, and the risk of leakage was increased. When the injection volume reached 2.0 ml, the risk of cement leakage was lower for screws having diameter-tapered perforations. The pullout strengths of the augmented FPS-A groups and FPS-B groups were higher than that of the CPS group (p < 0.0001). All FPS-B groups had a higher pullout strength than the FPS-A groups.

CONCLUSIONS

The diameter of the perforations affects the distribution of PMMA cement. The diameter-tapered design enabled PMMA to form larger bone-PMMA interfaces and achieve a relatively higher pullout strength, although statistical significance was not reached. Study results indicated 1.5-ml of PMMA was a conservative volume for PMMA augmentation; more cement injection would significantly increase the risk of cement leakage.

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Chih-Hsiang Liao, Jau-Ching Wu, Wen-Cheng Huang, Wei-Hsin Wang, Peng-Yuan Chang, Henrich Cheng, and Yang-Shih

Surgical treatment of thoracic disc herniation is technically challenging from anterior, lateral or posterior approaches. Because of the deeply located thoracic discs and non-retractable thoracic thecal sac, standard anterior and lateral procedures for discectomy require extensive tissue dissection causing prolonged lengths of stay in hospital. In this video, the authors present a case of calcified disc herniation at the level of T10/11 causing paraplegia and voiding difficulty. The patient was operated on via an endoscope-assisted minimally invasive transforaminal thoracic interbody fusion (EA-TTIF). The herniated disc and calcification were removed through a 26-mm tubular retractor, under microscopes via a unilateral transpedicular approach. The endoscopes were used for direct visualization of the ventral thecal sac and confirmation of complete decompression. After the operation, the patient's neurological function completely recovered. Minimally invasive EA-TTIF is a viable and effective option for the surgical management of thoracic disc herniation. Thoracic interbody fusion can be achieved through a minimally invasive approach from the back.

The video can be found here: http://youtu.be/54rRMtvSyCM.

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Hsuan-Kan Chang, Huang-Chou Chang, Jau-Ching Wu, Tsung-Hsi Tu, Li-Yu Fay, Peng-Yuan Chang, Ching-Lan Wu, Wen-Cheng Huang, and Henrich Cheng

OBJECT

The aim of this paper was to investigate the risk of recurrence of lumbar disc herniation (LDH) in patients with scoliosis who underwent microdiscectomy.

METHODS

A series of consecutive patients who underwent microdiscectomy for LDH was retrospectively reviewed. The inclusion criteria were young adults younger than 40 years who received microdiscectomy for symptomatic 1-level LDH. An exclusion criterion was any previous spinal surgery, including fusion or correction of scoliosis. The patients were divided into 2 groups: those with scoliosis and those without scoliosis. The demographic data in the 2 groups were similar. All medical records and clinical and radiological evaluations were reviewed.

RESULTS

A total of 58 patients who underwent 1-level microdiscectomy for LDH were analyzed. During the mean follow-up of 24.6 months, 6 patients (10.3%) experienced a recurrence of LDH with variable symptoms. The recurrence rate was significantly higher among the scoliosis group than the nonscoliosis group (33.3% vs 2.3%, p = 0.001). Furthermore, the recurrence-free interval in the scoliosis group was short.

CONCLUSIONS

Young adults (< 40 years) with uncorrected scoliosis are at higher risk of recurrent LDH after microdiscectomy.

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Chih-Chang Chang, Wen-Cheng Huang, Tsung-Hsi Tu, Peng-Yuan Chang, Li-Yu Fay, Jau-Ching Wu, and Henrich Cheng

OBJECTIVE

To avoid jeopardizing an aberrant vertebral artery, there are three common options in placing a C2 screw, including pedicle, pars, and translaminar screws. Although biomechanical studies have demonstrated similar strength among these C2 screws in vitro, there are limited clinical data to address their differences in vivo. When different screws were placed in each side, few reports have compared the outcomes. The present study aimed to evaluate these multiple combinations of C2 screws.

METHODS

Consecutive adult patients who underwent posterior atlantoaxial (AA) fixation were retrospectively reviewed. Every patient uniformly had bilateral C1 lateral mass screws in conjunction with 2 C2 screws (1 C2 screw on each side chosen among the three options: pedicle, pars, or translaminar screws, based on individualized anatomical consideration). These patients were then grouped according to the different combinations of C2 screws for comparison of the outcomes.

RESULTS

A total of 63 patients were analyzed, with a mean follow-up of 34.3 months. There were five kinds of construct combinations of the C2 screws: 2 pedicle screws (the Ped-Ped group, n = 24), 2 translaminar screws (the La-La group, n = 7), 2 pars screws (the Pars-Pars group, n = 6), 1 pedicle and 1 pars screw (the Ped-Pars group, n = 7), and 1 pedicle and 1 translaminar screw (the Ped-La group, n = 19). The rate of successful fixation in each of the groups was 100%, 57.1%, 100%, 100%, and 78.9% (Ped-Ped, La-La, Par-Par, Ped-Par, and Ped-La, respectively). The patients who had no translaminar screw had a higher rate of success than those who had 1 or 2 translaminar screws (100% vs 73.1%, p = 0.0009). Among the 5 kinds of construct combinations, 2 C2 pedicle screws (the Ped-Ped group) had higher rates of success than 1 C2 pedicle and 1 C2 translaminar screw (the Ped-La group, p = 0.018). Overall, the rate of successful fixation was 87.3% (55/63). There were 7 patients (4 in the Ped-La group and 3 in the La-La group) who lost fixation/reduction, and they all had at least 1 translaminar screw.

CONCLUSIONS

In AA fixation, C2 pedicle or pars screws or a combination of both provided very high success rates. Involvement of 1 or 2 C2 translaminar screws in the construct significantly lowered success rates. Therefore, a C2 pars screw is recommended over a translaminar screw.

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Chih-Chang Chang, Jau-Ching Wu, Peng-Yuan Chang, Mei-Yin Yeh, Yi-Hsuan Kuo, Li-Yu Fay, Tsung-Hsi Tu, Wen-Cheng Huang, and Henrich Cheng

There are many kinds of artificial discs available for cervical disc arthroplasty (CDA), with various designs of fixation and articulation mechanisms. Each of these designs has different features and theoretically fits most optimally in selected types of patients. However, there has been insufficient literature to guide individualized selection among these CDA devices. Since CDA aims to restore the joint function rather than arthrodesis, tailor-made size, shape, and mechanical properties should be taken into account for each candidate's target disc. Despite several large-scale prospective randomized control trials that have demonstrated the effectiveness and durability of CDA for up to 8 years, none of them involved more than one kind of artificial disc. In this video the authors present detailed steps and technical aspects of the newly introduced ProDisc-C Vivo (DePuy Synthes Spine), which has the same ball-and-socket design for controlled, predictable motion as the ProDisc-C. The newly derived teeth fixation provides high primary stability and multilevel capability by avoidance of previous keel-related limitations and complications (e.g., split vertebral fracture). Please note that the ProDisc-C Vivo is currently not available on the US market.

The authors present the case of a 53-year-old woman who had symptoms of both radiculopathy and myelopathy caused by a large, calcified disc herniation at C4–5. There was no improvement after 4 months of medical treatment and rehabilitation. A single-level CDA was successfully performed with the ProDisc-C Vivo, and her symptoms were completely ameliorated afterward. The follow-up images demonstrated preservation of motion at the indexed level.

The video can be found here: https://youtu.be/4DSES1xgvQU.

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Chih-Chang Chang, Li-Yu Fay, Jau-Ching Wu, Peng-Yuan Chang, Tsung-Hsi Tu, Henrich Cheng, and Wen-Cheng Huang