Summary

BACKGROUND
Spine surgery has the potential to benefit from additive manufacturing/3-dimensional printing (3DP) technology with complex anatomical pathologies requiring reconstruction, with the potential to customize surgery to reduce operative times, reduce blood loss, provide immediate stability, and potentially improve fusion rates. We report a unique case of intraoperative trial placement of a custom patient-specific implant (PSI) versus the final implantation of a customizable off-the-shelf (OTS) implant. Data collected for comparison included time to implant, ease of implantation, firmness of press-fit, and fixation options after implantation.

CASE DESCRIPTION
A 64-year-old man presented with low back pain.  Computed tomography and magnetic resonance imaging revealed a solitary lesion in the L5 vertebral body, confirmed by positron emission tomography scan.  Removal of the L5 vertebral body was performed, and reconstruction was achieved with an expandable cage. The time of implant insertion was minimal with the PSI (90 seconds) versus the OTS (>40 minutes). Immediate press-fit and “firmness” of implantation was clearly superior with the PSI, although this was an intraoperative subjective  assessment. Other benefits include integral fixation that is predetermined with the PSI, reduced time and blood loss, and ease of bone grafting with a PSI.

CONCLUSIONS
Use of 3DP has been able to reduce operative time significantly.  Surgeons can train before performing complex procedures, which enhances their presurgical planning, with the goal to maximize patient outcomes.  When considering implants and prostheses, the use of 3DP allows a superior anatomical fit for the patient, with the potential to improve restoration of anatomy.

Summary

BACKGROUND
Anterior lumbar interbody fusion (ALIF) is a surgical technique indicated for the treatment of several lumbar pathologies. Smoking has been suggested as a possible cause of reduced fusion rates after ALIF, although the literature regarding the impact of smoking status on lumbar spine surgery is not well established. This study aims to assess the impact of perioperative smoking status on the rates of perioperative complications, fusion, and adverse clinical outcomes in patients undergoing ALIF surgery.

METHODS
A retrospective analysis was performed on a prospectively maintained database of 137 patients, all of whom underwent ALIF surgery by the same primary spine surgeon. Smoking status was defined by the presence of
active smoking in the 2 weeks before the procedure.  Outcome measures included fusion rates, surgical complications, Short-Form 12, and Oswestry Disability Index.

RESULTS
Patients were separated into nonsmokers (n [ 114) and smokers (n [ 23). Univariate analysis demonstrated that the percentage of patients with successful fusion differed significantly between the groups (69.6% vs.
85.1%, P [ 0.006). Pseudarthrosis rates were shown to be significantly associated with perioperative smoking. Results for other postoperative complications and clinical outcomes were similar for both groups. On multivariate analysis, the rate of failed fusion was significantly greater for smokers than nonsmokers (odds ratio 37.10, P [ 0.002).

CONCLUSIONS
The rate of successful fusion after ALIF surgery was found to be significantly lower for smokers compared with nonsmokers. No significant association was found between smoking status and other perioperative complications or adverse clinical outcomes.

Summary

BACKGROUND
Neurosurgery and spine surgery have the potential to benefit from the use of 3-dimensional printing (3DP) technology due to complex anatomic considerations and the delicate nature of surrounding structures. We report a procedure that uses a 3D-printed titanium T9 vertebral body implant post T9 vertebrectomy for a primary bone tumor.

CASE DESCRIPTION
A 14-year-old female presented with progressive kyphoscoliosis and a pathologic fracture of the T9 vertebra with sagittal and coronal deformity due to a destructive primary bone tumor. Surgical resection and reconstruction was performed in combination with a 3D-printed, patient specific implant. Custom design features included porous titanium end plates, corrective angulation of the implant to restore sagittal balance, and pedicle screw holes in the 3D implant to assist with insertion of the device. In addition, attachment of the anterior column construct to the posterior pedicle screw construct was possible due to the customized features of the patient-specific implant.

CONCLUSIONS
An advantage of 3DP is the ability to manufacture patient specific implants, as in the current case example. Additionally, the use of 3DP has been able to reduce operative time significantly. Surgical procedures can be preplanned using 3DP patient-specific models. Surgeons can train before performing complex procedures, which enhances their presurgical planning in order to maximize patient outcomes. When considering implants and prostheses, the use of 3DP allows a superior anatomic fit for the patient, with the potential to improve restoration of anatomy.

Summary

BACKGROUND
En bloc resection of Ewing sarcoma in the cervical spine according to Enneking’s principles is technically challenging owing to the proximity of important neurovascular structures, the complex local anatomy, and the biomechanical instability of radical resection. The rarity of Ewing sarcoma and variability of its presentation justifies ongoing exploration and compilation of the surgical nuances and subtleties of en bloc resection in the cervical spine.

CASE DESCRIPTION
We present a 34-year-old male with Ewing sarcoma of the neck who underwent successful en bloc resection using a novel technique of splitting the laminae and osteomizing the lateral masses under imaging guidance.

CONCLUSIONS
This novel and successful approach of en bloc resection in the cervical spine can add to the spinal surgeon’s repertoire when dealing with complex cervical tumor masses.

Summary

Lumbar spinal stenosis is typically a degenerative condition that leads to compression of the spinal canal and lateral recess, resulting in leg pain and walking disability. Surgical management is indicated after failure of non-surgical management or rapidly worsening neurological impairment. The traditional approach is a laminectomy with foraminotomy and partial facetectomy but a newer minimally invasive option, unilateral laminectomy for bilateral decompression (ULBD), seems to demonstrate the better postoperative outcomes due to its unilateral exposure. ULBD involves a midline incision, opening the thoracolumbar fascia, retracting the paravertebral muscles unilaterally, then a hemilaminectomy, flavectomy, and decompression of the spinal canal with foraminotomy or partial facetectomy. The clinical decision on which side to approach spinal stenosis with ULBD has not been discussed in the literature. We have come up with an algorithm to decide which side to approach for ULBD based on position of spinous process and angulation, side of maximal compression, and surgeon handedness.

Summary

The study aims to describe a three-dimensional printed (3DP) posterior fixation implant used for C1/C2 fusion in a 65-year-old female. Spinal fusion remains a common intervention for a range of spinal pathologies including degenerative disc and facet disease when conservative methods are unsuccessful. However, fusion devices are not always entirely efficacious in providing the desired fixation, and surgeons rely on ‘off the shelf’ implants which may not provide an anatomical fit to address the particular pathology. 3DP refers to a process where three-dimensional objects are created through successive layering of material, so called ‘additive manufacturing’. Although this technology enables accurate fabrication of patient-specific orthopaedic and spinal implants, literature on its utilization in this regard is rare. A 65-year-old female, with severe facet arthropathy at the C1/C2 level, osteophyte formation and impingement of the exiting C2 nerve root underwent a C1/C2 posterior fusion and rhizolysis of the C2 nerve roots. A custom posterior fixation implant was designed and on-laid over the C2 spinous process and lamina, with screw holes made to a depth and angulation that was pre-calculated based on the preoperative CT based 3D modelling. The patient had an uneventful recovery and reported a significant reduction in occipital neuralgia and sub-occipital pain and 2-month follow-up. We report the first case of a customized 3DP spinal prosthesis for posterior C1/C2 fusion. The implant added significant value reducing the overall time of the procedure, and safety with a reduced risk of neurovascular compromise.

Summary

OBJECTIVE
There has been a recent renewed interest in the use and potential applications of 3D printing in the assistance of surgical planning and the development of personalized prostheses. There have been few reports on the use of 3D printing for implants designed to be used in complex spinal surgery.

METHODS
The authors report 2 cases in which 3D printing was used for surgical planning as a preoperative mold, and for a custom-designed titanium prosthesis: one patient with a C-1/C-2 chordoma who underwent tumor resection and vertebral reconstruction, and another patient with a custom-designed titanium anterior fusion cage for an unusual congenital spinal deformity.

RESULTS
In both presented cases, the custom-designed and custom-built implants were easily slotted into position, which facilitated the surgery and shortened the procedure time, avoiding further complex reconstruction such as harvesting rib or fibular grafts and fashioning these grafts intraoperatively to fit the defect. Radiological follow-up for both cases demonstrated successful fusion at 9 and 12 months, respectively.

CONCLUSIONS
These cases demonstrate the feasibility of the use of 3D modeling and printing to develop personalized prostheses and can ease the difficulty of complex spinal surgery. Possible future directions of research include the combination of 3D-printed implants and biologics, as well as the development of bioceramic composites and custom implants for load-bearing purposes.

Abstract

BACKGROUND CONTEXT
Extradural lumbar schwannomas are a rare form of nerve sheath tumors (NSTs). The typical management approach for extradural foraminal NSTs is total gross resection, which involves a midline incision and muscle exposure, followed by laminectomy and facetectomy to access the tumor for resection. Following tumor removal, spinal fusion is often indicated to reduce postoperative deformity, pain, and neurologic deficits.

PURPOSE
We report the case of a 34-year-old woman who presented with a 2-year history of progressive dysesthesia and left foot drop. Magnetic resonance imaging revealed a lesion in the lateral L5/S1 foramen. A novel anterior-retroperitoneal approach was used to access the tumor, via muscle splitting, retraction of peritoneum medially and psoas muscle or  iliac vessels laterally.

STUDY DESIGN/SETTING
This study is a case report of a novel approach for extradural lumbar
schwannomas.

METHODS
The methods involve a description of the approach and reporting of clinical findings.

RESULTS
The schwannoma was successfully resected without requiring additional fusion surgery.  The patient recovered uneventfully and was discharged on day 2 post operation.

CONCLUSION
We propose that the anterior-retroperitoneal approach is a viable technique for resection of lumbar foraminal NSTs without the need for fusion surgery.

© 2015 Elsevier Inc. All rights reserved.

Summary

Degenerative disc and facet joint disease of the lumbar spine is common in the ageing population, and is one of the most frequent causes of disability. Lumbar spondylosis may result in mechanical back pain, radicular and claudicant symptoms, reduced mobility and poor quality of life. Surgical interbody fusion of degenerative levels is an effective treatment option to stabilize the painful motion segment, and may provide indirect decompression of the neural elements, restore lordosis and correct deformity. The surgical options for interbody fusion of the lumbar spine include: posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF), minimally invasive transforaminal lumbar interbody fusion (MI-TLIF), oblique lumbar interbody fusion/anterior to psoas (OLIF/ATP), lateral lumbar interbody fusion (LLIF) and anterior lumbar interbody fusion (ALIF). The indications may include: discogenic/facetogenic low back pain, neurogenic claudication, radiculopathy due to foraminal stenosis, lumbar degenerative spinal deformity including symptomatic spondylolisthesis and degenerative scoliosis. In general, traditional posterior approaches are frequently used with acceptable fusion rates and low complication rates, however they are limited by thecal sac and nerve root retraction, along with iatrogenic injury to the paraspinal musculature and disruption of the posterior tension band. Minimally invasive (MIS) posterior approaches have evolved in an attempt to reduce approach related complications. Anterior approaches avoid the spinal canal, cauda equina and nerve roots, however have issues with approach related abdominal and vascular complications.

In addition, lateral and OLIF techniques have potential risks to the lumbar plexus and psoas muscle. The present study aims firstly to comprehensively review the available literature and evidence for different lumbar interbody fusion (LIF) techniques. Secondly, we propose a set of recommendations and guidelines for the indications for interbody fusion options. Thirdly, this article provides a description of each approach, and illustrates the potential benefits and disadvantages of each technique with reference to indication and spine level performed.

Summary

Study Design
Prospective observational study.

Objective
Patient-based subjective ratings of symptoms and function have traditionally been used to gauge the success and extent of recovery following spine surgery. The main drawback of this type of assessment is the inherent subjectivity involved in patient scoring.We aimed to objectively measure functional outcome in patients having lumbar spine surgery using quantitative physical activity measurements derived from accelerometers.

Methods
A prospective study of 30 patients undergoing spine surgery was conducted with subjective outcome scores (visual analog scale [VAS], Oswestry Disability Index [ODI] and Short Form 12 [SF-12]) recorded; patients were given a Fitbit accelerometer (Fitbit Inc., San Francisco, California, United States) at least 7 days in advance of surgery to record physical activity (step count, distance traveled, calories burned) per day.
Following surgery, postoperative activity levels were reported at 1-, 2-, and 3-month follow-up.

Results
Of the 28 compliant patients who completed the full trial period, mean steps taken per day increased 58.2% (p ¼ 0.008) and mean distance traveled per day increased 63% (p ¼ 0.0004) at 3-month follow-up. Significant improvements were noted for mean changes in VAS back pain, VAS leg pain, ODI, and SF-12 Physical Component Summary (PCS) scores. There was no significant correlation between the improvement in steps or distance traveled per day with improvements in VAS back or leg pain, ODI, or PCS scores at follow-up.

Conclusions
High compliance and statistically significant improvement in physical activity were demonstrated in patients who had lumbar decompression and lumbar fusion. There was no significant correlation between improvements in subjective clinical outcome scores with changes in physical activity measurements at follow-up. Limitations of the present study include its small sample size, and the validity of objective physical activity measurements should be assessed in future larger,  prospective studies.