Three-Dimensional-Printed Drill Guides for Occipitothoracic Fusion in a Pediatric Patient With Occipitocervical Instability

BACKGROUND: Pediatric occipitothoracic fusion can be challenging because of small size pedicles and thin occipital bone. Three-dimensional (3D) printing technology can help with accurate screw insertion but has not been described for occipital keel plate positioning so far. OBJECTIVE: To describe the novel use of 3D technology to position occipital keel plates during pediatric occipitothoracic fixation. METHODS: A young boy with segmental spinal dysgenesis presented with asymmetrical pyramidal paresis in all limbs. Developmental abnormities of the cervical spine caused a thinned spinal cord, and because of progressive spinal cord compression, surgical intervention by means of occipitothoracic fixation was indicated at the age of 3 yr. Because of the small-size pedicles and thin occipital bone, the pedicle screws and occipital plates were planned meticulously using 3D virtual surgical planning technology. The rods were virtually bent in order to properly align with the planned screws. By means of 3D-printed guides, the surgical plan was transferred to the operating theater. For the occipital bone, a novel guide concept was developed, aiming for screw positions at maximal bone thickness. RESULTS: The postoperative course was uneventful, and radiographs showed good cervical alignment. After superimposing the virtual plan with the intraoperative acquired computed tomography, it was confirmed that the occipital plate positions matched the virtual plan and that pedicle screws were accurately inserted without signs of breach. CONCLUSION: The use of 3D technology has greatly facilitated the performance of the occipitothoracic fixation and could, in the future, contribute to safer pediatric spinal fixation procedures

Three-Dimensional Planning and Use of Individualized Osteotomy-Guiding Templates for Surgical Correction of Kyphoscoliosis:A Technical Case Report

OBJECTIVE: We have described the use of 3-dimensional (3D) virtual planning and 3D printed patient-specific osteotomy templates in the surgical correction of a complex spinal deformity. Pedicle subtraction osteotomies (PSOs) for the correction of severe spinal deformities are technically demanding procedures with a risk of major complications. In particular, operations of the severely deformed spine call for new, more precise, methods of surgical planning. The new 3D technology could result in new possibilities for the surgical planning of spinal deformities. METHODS: We present the case of severe congenital kyphoscoliosis in a young girl with skeletal dysplasia. A closing wedge-extended PSO was 3D virtual planned using medical computer design software. After the optimal 3D-wedge procedure was planned, individualized osteotomy-guiding templates were designed for translation of the planned PSO to the surgical procedure. During surgery, the PSO was performed using the osteotomy templates. Successful correction of the kyphoscoliosis was realized. RESULTS: The kyphosis was successfully reduced using a wedge-shaped extended PSO using preoperative 3D virtual planning, assisted by 3D-printed individualized osteotomy-guiding templates. CONCLUSIONS: In addition to direct translation of the planned PSO for surgery, the 3D planning also facilitated a detailed preoperative evaluation, greater insight into the case-specific anatomy, and accurate planning of the required correction

Anterior or posterior approach in the surgical treatment of cervical radiculopathy; neurosurgeons' preference in the Netherlands

Objectives: Several surgical techniques are available for the treatment of cervical degenerative disease. For resolving cervical nerve root compression, anterior cervical discectomy with fusion (ACDF) or posterior cervical foraminotomy (PCF) can be applied. Amongst neurosurgeons, there seems to be a tendency to prefer ACDF, even though there are some advantages in favor of PCF. The objective of present study is to evaluate which factors determine the choice for an anterior or posterior surgical approach in patients with cervical radiculopathy based on foraminal pathology. Methods: A web-based survey was sent to all 133 neurosurgeons in the Netherlands. The study followed a mixed methods cross-sectional design. The first part of the survey focused on general perceived (dis)advantages of ACDF and PCF. The second part concerned questions about the choice between the two procedures. Furthermore, it was analyzed if exposure during training, amount of performed surgeries, assumed reoperation and complication rates influenced the choice of procedure by conducting Chi-square tests with post-hoc analysis. Results: A total of 56 neurosurgeons responded (42%). An overall preference for ACDF was observed, even when differentiating for a pure disc prolapse, a spondylotic or a combined stenosis of the neuroforamen. The most relative important factors for motivating the preference for either ACDF or PCF were: the assumed best decompression of the nerve root (18%), congruence with current literature (16%), exposure during residency (12%), personal comfort (11%) and experience (11%) with the technique. Conclusion: In this survey, there was an overall preference for ACDF above PCF for the surgical treatment of a foraminal cervical radiculopathy. In addition to subjective factors as "experience" and "comfort", the respondents often motivated their choice as "the best one according to literature". As there is currently no evidence about the superiority of any of the procedures in literature, this assumption is remarkable

Accuracy Assessment of Pedicle and Lateral Mass Screw Insertion Assisted by Customized 3D-Printed Drill Guides:A Human Cadaver Study

BACKGROUND: Accurate cervical screw insertion is of paramount importance considering the risk of damage to adjacent vital structures. Recent research in 3-dimensional (3D) technology describes the advantage of patient-specific drill guides for accurate screw positioning, but consensus about the optimal guide design and the accuracy is lacking. OBJECTIVE: To find the optimal design and to evaluate the accuracy of individualized 3D-printed drill guides for lateral mass and pedicle screw placement in the cervical and upper thoracic spine. METHODS: Five Thiel-embalmed human cadavers were used for individualized drill-guide planning of 86 screw trajectories in the cervical and upper thoracic spine. Using 3D bone models reconstructed from acquired computed tomography scans, the drill guides were produced for both pedicle and lateral mass screw trajectories. During the study, the initial minimalistic design was refined, resulting in the advanced guide design. Screw trajectories were drilled and the realized trajectories were compared to the planned trajectories using 3D deviation analysis. RESULTS: The overall entry point and 3D angular accuracy were 0.76 +/- 0.52 mm and 3.22 +/- 2.34 degrees, respectively. Average measurements for the minimalistic guides were 1.20 mm for entry points, 5.61 degrees for the 3D angulation, 2.38 degrees for the 2D axial angulation, and 4.80 degrees for the 2D sagittal angulation. For the advanced guides, the respective measurements were 0.66 mm, 2.72 degrees, 1.26 degrees, and 2.12 degrees, respectively. CONCLUSION: The study ultimately resulted in an advanced guide design including caudally positioned hooks, crosslink support structure, and metal inlays. The novel advanced drill guide design yields excellent drilling accuracy

Accuracy of Patient-Specific 3D-Printed Drill Guides for Pedicle and Lateral Mass Screw Insertion:An Analysis of 76 Cervical and Thoracic Screw Trajectories

STUDY DESIGN: Single-center retrospective case series. OBJECTIVE: The purpose of this study was to assess the safety and accuracy of 3D-printed individualized drill guides for pedicle and lateral mass screw insertion in the cervical and upper-thoracic region, by comparing the pre-operative 3D-surgical plan with the postoperative results. SUMMARY OF BACKGROUND DATA: Posterior spinal fusion surgery can provide rigid intervertebral fixation but screw misplacement involves a high risk of neurovascular injury. However, modern spine surgeons now have tools such as virtual surgical planning and 3D-printed drill guides to facilitate spinal screw insertion. METHODS: A total of 15 patients who underwent posterior spinal fusion surgery involving patient-specific 3D-printed drill guides were included in this study. After segmentation of bone and screws, the post-operative models were superimposed onto the preoperative surgical plan. The accuracy of the realized screw trajectories was quantified by measuring the entry point and angular deviation. RESULTS: The 3D deviation analysis showed that the entry point and angular deviation over all 76 screw trajectories were 1.40 ± 0.81 mm and 6.70 ± 3.77°, respectively. Angular deviation was significantly higher in the sagittal plane than in the axial plane (P = 0.02). All screw positions were classified as 'safe' (100%), showing no neurovascular injury, facet joint violation, or violation of the pedicle wall. CONCLUSIONS: 3D virtual planning and 3D-printed patient-specific drill guides appear to be safe and accurate for pedicle and lateral mass screw insertion in the cervical and upper-thoracic spine. The quantitative 3D deviation analyses confirmed that screw positions were accurate with respect to the 3D-surgical plan. LEVEL OF EVIDENCE: 4

Fluorescence-guided detection of pituitary neuroendocrine tumor (PitNET) tissue during endoscopic transsphenoidal surgery available agents, their potential, and technical aspects

Differentiation of pituitary neuroendocrine tumor (PitNET) tissue from surrounding normal tissue during surgery is challenging. A number of fluorescent agents is available for visualization of tissue discrepancy, with the potential of improving total tumor resection. This review evaluates the availability, clinical and technical applicability of the various fluorescent agents within the field of pituitary surgery. According to PRISMA guidelines, a systematic review was performed to identify reports describing results of in vivo application of fluorescent agents. In this review, 15 publications were included. Sodium Fluorescein (FNa) was considered in two studies. The first study reported noticeable fluorescence in adenoma tissue, the second demonstrated the strongest fluorescence in non-functioning pituitary adenomas. 5-Aminolevulinic acid (5-ALA) was investigated in three studies. One study compared laser-based optical biopsy system (OBS) with photo-diagnostic filter (PD) and found that the OBS was able to detect all microadenomas, even when MRI was negative. The second study retrospectively analyzed twelve pituitary adenomas and found only one positive for fluorescence. The third investigated fifteen pituitary adenomas of which one displayed vague fluorescence. Indocyanine green (ICG) was researched in four studies with variable results. Second-Window ICG yielded no significant difference between functioning and non-functioning adenomas in one study, while a second study displayed 4 times higher fluorescence in tumor tissue than in normal tissue. In three studies, OTL38 showed potential in non-functioning pituitary adenomas. At present, evidence for fluorescent agents to benefit total resection of PitNETs is lacking. OTL38 can potentially serve as a selective fluorescent agent in non-functioning pituitary adenomas in the near future

Minimally invasive surgery versus open surgery in the treatment of lumbar spondylolisthesis:Study protocol of a multicentre, randomised controlled trial (MISOS trial)

Introduction Patients with symptomatic spondylolisthesis are frequently treated with nerve root decompression, in addition to pedicle screw fixation and interbody fusion. Minimally invasive approaches are gaining attention in recent years, although there is no clear evidence supporting the proclamation of minimally invasive spine surgery (MISS) being better than open surgery. We present the design of the MISOS (Minimal Invasive Surgery versus Open Surgery) trial on the effectiveness of MISS versus open surgery in patients with degenerative or spondylolytic spondylolisthesis. Methods and analysis All patients (age 18-75 years) with neurogenic claudication or radicular leg pain based on low-grade degenerative or spondylolytic spondylolisthesis with persistent complaints for at least 3 months are eligible. Patients will be randomised into mini-open decompression with bilateral interbody fusion with percutaneous pedicle screw fixation (MISS), or conventional surgery with decompression and instrumented fusion with pedicle screws and bilateral interbody fusion (open). The primary outcome measure is Visual Analogue Scale of self-reported low back pain. Secondary outcome measures include improvement of leg pain, Oswestry Disability Index, patients' perceived recovery, quality of life, resumption of work, complications, blood loss, length of hospital stay, incidence of reoperations and documentation of fusion. This study is designed as a multicentre, randomised controlled trial in which two surgical techniques are compared in a parallel group design. Based on a 20 mm difference of low back pain score at 6 weeks (power of 90%, assuming 8% loss to follow-up), a total of 184 patients will be needed. All analyses will be performed according to the intention-to-treat principle. Ethics and dissemination The study has been approved by the Medical Ethical Review Board Southwest Holland in August 2014 (registration number NL 49044.098.14) and subsequently approved by the board of all participating hospitals. Dissemination will include peer-reviewed publications and presentations at national and international conferences

An aggressive poorly differentiated plurihormonal Pit-1-positive adenoma

In July 2017, a 35-year-old woman was referred to our care for treatment of a large pituitary mass with an unusually high growth rate. She presented with right-sided ptosis and diplopia (n. III palsy), increasing retrobulbar pain and vertigo. Although laboratory investigations were consistent with acromegaly, she exhibited no clear phenotypic traits. During transsphenoidal surgery aimed at biopsy, typical adenomatous tissue was encountered, upon which it was decided to proceed to debulking. Histopathological analysis demonstrated a poorly differentiated plurihormonal Pit-1-positive adenoma with focal growth hormone (GH) and prolactin positivity, positive SSTR2 staining and a Ki-67 of 20–30%. Postoperative magnetic resonance imaging (MRI) examination revealed a large tumour remnant within the sella invading the right cavernous sinus with total encasement of the internal carotid artery and displacement of the right temporal lobe. As a consequence, she was treated additionally with radiotherapy, and a long-acting first-generation somatostatin analogue was prescribed. Subsequently, the patient developed secondary hypocortisolism and diabetes mellitus despite adequate suppression of GH levels. In September 2019, her symptoms recurred. Laboratory evaluations indicated a notable loss of biochemical control, and MRI revealed tumour progression. Lanreotide was switched to pasireotide, and successful removal of the tumour remnant and decompression of the right optic nerve was performed. She received adjuvant treatment with temozolomide resulting in excellent biochemical and radiological response after three and six courses. Symptoms of right-sided ptosis and diplopia remained. Evidence for systemic therapy in case of tumour progression after temozolomide is currently limited, although various potential targets can be identified in tumour tissue