Spinal instrumentation in infants, children, and adolescents: a review

Paraspinous Muscle Flaps in Complex Pediatric Spine Surgeries: A 12-Year Single Institution Experience

PURPOSE

The benefits of paraspinous flaps in adult complex spine surgery patients are established in the literature; however, their use in pediatric patients has not been well described. This study compares clinical outcomes with and without paraspinous muscle flap closure in pediatric patients who have undergone spine surgery.

METHODS

We conducted a retrospective review of all pediatric spine surgeries at the University of California, San Francisco from 2011 to 2022. Patients were divided into 2 cohorts based on whether the plastic surgery service closed or did not close the wound with paraspinous muscle flaps. We matched patients by age, American Society of Anesthesiology classification, prior spinal surgical history, and diagnosis. Surgical outcomes were compared between the 2 cohorts.

RESULTS

We identified 226 pediatric patients who underwent at least one spinal surgery, 14 of whom received paraspinous flap closure by plastic surgery. They were matched in a 1:4 ratio with controls (n = 56) that did not have plastic surgery closure. The most common indication for plastic surgery involvement was perceived complexity of disease by the spine surgeon with concern for inadequate healthy tissue coverage (78.6%), followed by infection (21.4%). Postoperative complications were similar between the two groups. The plastic surgery cohort had a higher rate of patients who were underweight (57.1% vs 14.3%, P < 0.01) and had positive preoperative wound cultures (28.6% vs 8.9%, P = 0.05), as well as a higher rate of postoperative antibiotic usage (78.6 vs 17.9%, P < 0.01). There was no difference in recorded postoperative outcomes.

CONCLUSIONS

Spine surgeons requested paraspinous flap closure for patients with more complex disease, preoperative infections, history of chemotherapy, or if they were underweight. Patients with paraspinous flap coverage did not have increased postoperative complications despite their elevated risk profile. Our findings suggest that paraspinous muscle flaps should be considered in high-risk pediatric patients who undergo spine surgery.

Clinical Considerations and Outcomes for Spine Surgery Patients with a History of Transplant: A Systematic Scoping Review

OBJECTIVE

The objective of this study was to investigate the perioperative management and outcomes of patients with a prior history of successful transplantation undergoing spine surgery.

METHODS

We searched Medline, Embase, and Cochrane Central Register of Controlled Trials for matching reports in July 2021. We included case reports, cohort studies, and retrospective analyses, including terms for various transplant types and an exhaustive list of key words for various forms of spine surgery.

RESULTS

We included 45 studies consisting of 34 case reports (published 1982-2021), 3 cohort analyses (published 2005-2006), and 8 retrospective analyses (published 2006-2020). The total number of patients included in the case reports, cohort studies, and retrospective analysis was 35, 48, and 9695, respectively. The mean 1-year mortality rate from retrospective analyses was 4.6% ± 1.93%, while the prevalence of perioperative complications was 24%. Cohort studies demonstrated an 8.5% ± 12.03% 30-day readmission rate. The most common procedure performed was laminectomy (38.9%) among the case reports. Mortality after spine surgery was noted for 4 of 35 case report patients (11.4%).

CONCLUSIONS

This is the first systematic scoping review examining the population of transplant patients with subsequent unrelated spine surgery. There is significant heterogeneity in the outcomes of post-transplant spine surgery patients. Given the inherent complexity of managing this group and elevated mortality and complications compared to the general spine surgery population, further investigation into their clinical care is warranted.

Pediatric spinal instrumentation

This article reviews the evolution of spinal instrumentation in the pediatric age group, starting with the cervical spine and atlantoaxial area and ending with the lower spine. The congenital and the acquired conditions which require instrumentation are described. The technical details regarding pediatric instrumentation are alluded to, and finally an attempt is made to predict the future of spinal instrumentation in this age group.

Non-dysraphic intramedullary spinal cord lipoma of the child: Report of 3 cases

BACKGROUND AND PURPOSE

Non-dysraphic intramedullary spinal cord lipomas (NDSCL) represent 1% of spinal cord tumors. They are less frequent than dysraphic spinal cord lipomas and clinical presentation is unspecific. There are no guidelines on surgical management.

MATERIAL AND METHODS

We report three observations of NDSCL in children, focusing on the clinical presentation, surgical management and postoperative outcome.

RESULTS

The patients, one female and two males, aged from 5 months to 10 years presented with neurological deterioration, pain, spinal rigidity and in two cases, a subcutaneous mass. Spinal MRI found intradural lipomas without spina bifida, located in the cervico-thoracic area in all cases. The lipoma extended to the medulla oblongata in two cases and was in the lumbar region in the third. These lipomas were massive, requiring decompression surgery. Surgery confirmed the lipoma to be subpial. We performed debulking of the lipoma without attempting total resection, and with or without dural plasty and laminoplasty, followed by minerva cast in two cases, and avoidance of standing in the youngest. Satisfactory recovery occurred in all three cases. After a follow-up between 4 months and 9 years, the outcome was favorable in all cases, and no patient presented with secondary spinal deformation or lipoma progression.

CONCLUSION

NDSCL is a rare entity, which often manifests with progressive pain and neurological deficits. In our experience, partial resection with or without dural plasty and laminoplasty has been associated with satisfactory postoperative outcomes and no recurrence of symptoms. We should be attentive to the risk of postoperative spinal deformity in these young patients.

Posterior cervical spinal fusion in the pediatric population using modern adult instrumentation - clinical outcome and safety

PURPOSE

Traditionally, less rigid fixation techniques have been applied to the pediatric cervical spine. There is a lack of long-term outcome data for rigid fixation techniques. The purpose of this study was to define the clinical outcome and safety of posterior instrumented fusion in the pediatric population using adult posterior instrumentation.

METHODS

A multicenter, retrospective review of pediatric patients who underwent posterior cervical fusion using a 3.5 mm posterior cervical system for any indication was performed. Outcome parameters included complications, revision and fusion rates, operative time (OR), blood loss, and postoperative neurologic status. Outcomes were compared between patient groups (posterior only versus anterior/posterior approach, short versus intermediate versus long fusion, and between different etiologies) using Mann-Whitney and chi-square test.

RESULTS

Seventy-nine patients with a mean age of 9.9 years and mean follow-up of 2.8 years were included. At baseline 44 (56%) had an abnormal neurologic exam. Congenital deformities and basilar invagination were the most common indications for surgery. Posterior-only surgery was performed in 71 (90%) cases; mean number of levels fused was 4 (range 1-15). Overall, 4 (5%) operative complications and 4 (5%) revisions were reported at an average postoperative time of 2.6 years. Neurologic status remained unchanged in 74%, improved in 23%, and worsened in 3%. When comparing outcome measures between the various groups, 2 significant differences were found: OR was longer in the anterior/posterior approach group and decline of neuro status was more frequent in the long fusion group.

CONCLUSION

Posterior cervical fusion with an adult 3.5 mm posterior cervical system was safe in this cohort of 79 pediatric patients irrespective of surgical technique, fusion length, and etiology, resulting in a high fusion and low complication/revision rate.

3D model-assisted instrumentation of the pediatric spine: a technical note

Background

Instrumentation of the pediatric spine is challenging due to anatomical constraints and the absence of specific instrumentation, which may result in iatrogenic injury and implant failure, especially in occipito-cervical constructs. Therefore, preoperative planning and in vitro testing of instrumentation may be necessary.

Methods

In this paper, we present a technical note on the use of 1:1 scale patient-specific 3D printed spinal models for preoperative assessment of feasibility of spinal instrumentation with conventional spinal implants in pediatric spinal pathologies.

Results

The printed 3D models fully matched the intraoperative anatomy and allowed a preoperative confirmation of the feasibility of the planned instrumentation with conventional screws for adult patients. In addition, the possibility of intraoperative model assessment resulted in better intraoperative sense of spinal anatomy and easier freehand screw insertion, thereby reducing the potential for iatrogenic injury. All 3D models were printed at the surgical department at a very low cost, and the direct communication between the surgeon and the dedicated specialist allowed for multiple models or special spinal segments to be printed for more detailed consideration.

Conclusions

Our technical note highlights the critical steps for preoperative virtual planning and in vitro testing of spinal instrumentation on patient-specific 3D printed models at 1:1 scale. The simple and affordable method helps to better visualize pediatric spinal anatomy and confirm the suitability of preplanned conventional spinal instrumentation, thereby reducing X-ray exposure and intraoperative complications in freehand screw insertion without navigation.

Removal of instrumentation for postoperative spine infection: systematic review

OBJECTIVE

Currently, no consensus exists as to whether patients who develop infection of the surgical site after undergoing instrumented fusion should have their implants removed at the time of wound debridement. Instrumentation removal may eliminate a potential infection nidus, but removal may also destabilize the patient's spine. The authors sought to summarize the existing evidence by systematically reviewing published studies that compare outcomes between patients undergoing wound washout and instrumentation removal with outcomes of patients undergoing wound washout alone. The primary objectives were to determine 1) whether instrumentation removal from an infected wound facilitates infection clearance and lowers morbidity, and 2) whether the chronicity of the underlying infection affects the decision to remove instrumentation.

METHODS

PRISMA guidelines were used to review the PubMed/MEDLINE, Embase, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.gov databases to identify studies that compared patients with implants removed and patients with implants retained. Outcomes of interest included mortality, rate of repeat wound washout, and loss of correction.

RESULTS

Fifteen articles were included. Of 878 patients examined in these studies, 292 (33%) had instrumentation removed. Patient populations were highly heterogeneous, and outcome data were limited. Available data suggested that rates of reoperation, pseudarthrosis, and death were higher in patients who underwent instrumentation removal at the time of initial washout. Three studies recommended that instrumentation be uniformly removed at the time of wound washout. Five studies favored retaining the original instrumentation. Six studies favored retention in early infections but removal in late infections.

CONCLUSIONS

The data on this topic remain heterogeneous and low in quality. Retention may be preferred in the setting of early infection, when the risk of underlying spine instability is still high and the risk of mature biofilm formation on the implants is low. However, late infections likely favor instrumentation removal. Higher-quality evidence from large, multicenter, prospective studies is needed to reach generalizable conclusions capable of guiding clinical practice.

Comparison of Pedicle Screws Versus Hybrid Fixation With Sublaminar Polyester Bands in the Treatment of Neuromuscular Scoliosis

BACKGROUND

The choice of implants in neuromuscular scoliosis (NMS) surgery remains controversial. Sublaminar polyester bands (SPBs) seem to be a promising alternative implant. The purpose of current study was to compare clinical and radiologic results of posterior instrumentation and fusion using hybrid constructs versus only pedicle screws for NMS treatment.

METHODS

In 24 patients, pedicle screws were used in all segments, and 18 patients underwent hybrid fixation. Cobb angle, thoracic kyphosis, lumbar lordosis angles, and pelvic obliquity were compared before and immediately after surgery, at the last follow-up radiographs. Demographic, clinical information, duration of surgery, estimated blood loss (EBL), blood transfusion, and complications were compared between groups. Additionally, patients were assessed for pain with visual analog scale (VAS) and quality of life with Short Form 36 (SF-36) and the Oswestry scale.

RESULTS

Baseline characteristics of patients were similar except for EBL (P = 0.002) and follow-up duration (P = 0.004). The mean curve correction was 58.1% in the hybrid group, and 67.6% in the screw group (P = 0.07), and loss of correction was significantly lower in hybrid group (2.72° ± 1.48° vs. 3.66° ± 1.52°, P = 0.049). Functional scores at final follow-up were equal in both groups (VAS P = 0.865, Oswestry P = 0.097, SF-36 Physical P = 0.358, SF-36 Mental P = 0.145).

CONCLUSIONS

SPBs might be a better fixation alternative at the apex of rigid spinal deformity in NMS. The deformity can be corrected with less blood loss and at a similar rate of correction, with similar rate complications compared with pedicle screws.

A 3D-Printed Model-Assisted Cervical Spine Instrumentation after Tumor Resection in a 4-Year-Old Child: A Case Report

INTRODUCTION

In the case of tumor resection in the upper cervical spine, a multilevel laminectomy with instrumented fixation is required to prevent kyphotic deformity and myelopathy. Nevertheless, instrumentation of the cervical spine in children under the age of 8 years is challenging due to anatomical considerations and unavailability of specific instrumentation.

CASE PRESENTATION

We present a case of 3D-printed model-assisted cervical spine instrumentation in a 4-year-old child with post-laminectomy kyphotic decompensation of the cervical spine and spinal cord injury 1 year after medulloblastoma metastasis resection in the upper cervical spine. Due to unavailability of specific instrumentation, 3D virtual planning was used to assess and plan posterior cervical fixation. Fixation with 3.5 mm lateral mass and isthmic screws was suggested and the feasibility of fixation was confirmed "in vitro" in a 3D-printed model preoperatively to reduce the possibility of intraoperative implant-spine mismatch. Intraoperative conditions completely resembled the preoperative plan and 3.5 mm polyaxial screws were successfully used as planned. Postoperatively the child made a complete neurological recovery and 2 years after the instrumented fusion is still disease free with no signs of spinal decompensation.

DISCUSSION/CONCLUSION

Our case shows that posterior cervical fixation with the conventional screw-rod technique in a 4-year-old child is feasible, but we suggest that suitability and positioning of the chosen implants are preoperatively assessed in a printed 3D model. In addition, a printed 3D model offers the possibility to better visualize and sense spinal anatomy "in vivo," thereby helping screw placement and reducing the chance for intraoperative complications, especially in the absence of intraoperative spinal navigation.

Pedicle Screw System May Not Control Severe Spinal Rotational Instability

STUDY DESIGN

An in vitro biomechanical study.

OBJECTIVE

The purpose of this study is to discuss whether pedicle screw systems can control spinal rotational instability in a functional spinal unit of lumbar spine on human cadaver.

SUMMARY OF BACKGROUND DATA

Rotational experiments using deer lumbar cadaveric models showed that rotational range of motion (ROM) of the model fixed by a pedicle screw system with crosslinking after total facetectomy for both the sides was larger than that in the intact model, and stated that spinal rotational instability could not be controlled using a pedicle screw system.

METHODS

A rotation experiment using 10 functional spinal units (L3-4) of lumbar spine on human cadavers was performed by preparing the four models (intact model, damaged model, pedicle screw model, and crosslink (CL) model) in stages, then calculating and comparing rotational ROM among the four models.

RESULTS

Rotational ROM in the CL model was still larger than that of the intact model in all the samples. And, rotational ROM decreased in the order of damaged model >> pedicle screw model > CL model > intact model. Statistical analysis revealed significant differences between all models (P < 0.001).

CONCLUSIONS

Pedicle screw systems may not control severe spinal rotational instability in human lumbar cadaveric models with total facetectomy on both the sides. This may represent a major biomechanical drawback to the pedicle screw system.

LEVEL OF EVIDENCE

N/A.

Pediatric Scoliosis Surgery-A Comprehensive Analysis of Treatment-Specific Variables and Trends in Latvia

Background and Objectives: There are currently no data available regarding pediatric scoliosis surgery in Latvia. The aim of this article is to present treatment specific variables, investigate their interrelation, and identify predictors for the length of stay after surgical pediatric scoliosis correction. Materials and Methods: This retrospective study included all surgical pediatric scoliosis corrections in Latvia for the years 2012 to 2016. Analyzed parameters were chosen to portray the patients' demographics, pathology, as well as treatment specific variables. Descriptive, inferential, and linear regression statistics were calculated. Results: A total of 69 cases, 74% female and 26% male, were identified. The diagnostic subgroups consisted of 62% idiopathic (IDI) and 38% non-idiopathic (non-IDI) scoliosis cases. Non-IDI cases had significantly increased operation time, hospital stay, Cobb angle before surgery, and instrumented levels, while IDI cases showed significantly higher Cobb angle percentage correction. For all operated cases, the operation time and the hospital stay decreased significantly over the investigated time period. Early post-operative complications (PCs) occurred in 15.9% of the cases and were associated with increased hospital stay, instrumented levels, and Cobb angle before surgery. The linear regression analysis revealed that operation time and the presence of PCs were significant predictors for the length of the hospital stay. Conclusions: This is the first study to provide comprehensive insight into pediatric scoliosis surgery since its establishment in Latvia. Our regression model offers clinically applicable predictors and further underlines the significance of the operation length on the hospital stay. These results build the foundation for international comparison and facilitate improvement in the field.

The Efficacy of Ultrasonic Bone Scalpel for Unilateral Cervical Open-Door Laminoplasty: A Randomized Controlled Trial

BACKGROUND

In cervical open-door laminoplasty for cervical myelopathy, a high-speed rotatory drill and rongeurs are used to make unicortical troughs and bicortical openings in the laminae. The lamina is reflected at the trough to enlarge the spinal canal, followed by bone healing on the hinge side to stabilize laminoplasty. The ultrasonic bone scalpel (UBS) has been used due to theoretical advantages including a better hinge union rate, less soft tissue trauma, less neurological injury, and shorter operative time.

OBJECTIVE

To assess the superiority of UBS for hinge union compared to the drill through randomized controlled trial.

METHODS

In 190 randomly allocated cervical myelopathy patients, the trough and opening at the lamina were made using either the drill (n = 95) or UBS (n = 95) during 2015 to 2018. The primary outcome was the hinge union rate on 6-mo postoperative computed tomography. Secondary outcomes included the hinge union rate at 12 mo, the operative time, intraoperative/postoperative bleeding, neurological injury, complications, and clinical outcomes over a 24-mo follow-up.

RESULTS

Hinge union in all laminae was achieved in 60.0% (drill) and 43.9% (UBS) of patients at 6 mo (intention-to-treat analysis; P = .02; odds ratio, 2.1) and in 91.9% (drill) and 86.5% (UBS) at 12 mo. Dural injury only occurred in the drill group (2.1%), and the UBS group showed significantly less intraoperative bleeding (P < .01). The other secondary outcomes did not differ between groups.

CONCLUSION

The hinge union rate was inferior in the UBS group at 6 mo postoperatively, but UBS was efficacious in reducing dural injuries and bleeding.