Kerrison Rongeur Research Articles

AFFORDABLE VIRTUAL REALITY HAPTIC-FEEDBACK SURGICAL SIMULATOR: A PROOF OF CONCEPT

INTRODUCTIONSimulation plays an important role in surgical education and the ability to perfect surgical performance. Simulation can be enhanced by adding various layers of realism to the experience. Haptic feedback enhances the simulation experience by providing tactile responses and virtual reality imagery provides an immersive experience and allows for greater appreciation of three-dimensional structures. In this study, we present a proof-of-concept haptic simulator to replicate key steps of a cervical laminoplasty procedure. The technology uses affordable components and is easily modifiable so that it can be used from novice through to expert level. Custom models can be easily added ensuring the simulator can be used in a wide range of orthopaedic applications from baseline education through to day of surgery pre-operative simulation.METHODWe used the Unity Game Engine, the 3D Systems “Touch” Haptic Feedback Device (HFD), and a Meta Quest VR headset. Our system uses a number of complex algorithms to track the shape and provide haptic feedback of a virtual bone model. This allows for simulation of various tools including a high-speed burr, Kerrison rongeur and intraoperative X-rays.RESULTSOur simulator replicates the tactile sensations of bone-burring tasks. Although we focused on the cervical laminoplasty procedure, the system can load data from CT scans, enabling the simulation of multiple other procedures. The parts cost of our system, $10,000 NZD, is a fraction of the cost of traditional surgical simulators.DISCUSSIONOur simulator reduces financial barriers to accessing orthopaedic simulators. Trainees can perform hands-on practice without compromising patient safety. The immersive nature of VR, combined with realistic haptic feedback, enables trainees to develop the dexterity and three-dimensional understanding of detailed bony work. Further refinements are needed before we can perform validation studies on our system.CONCLUSIONSWe present an affordable surgical simulator capable of simulating bony surgical procedures in a VR environment using haptic feedback technology and consumer-grade components.ACKNOWLEDGEMENTSThis research was made possible by the generosity of the Wishbone Trust.

Ligamentum Flavum Flap Technique in Lumbar Microdiscectomy.

Microdiscectomy has been the gold-standard technique for the treatment of lumbar disc herniation. A potential reason for suboptimal symptom resolution following microdiscectomy is postoperative epidural fibrosis1. Preservation of the ligamentum flavum through the use of the ligamentum flavum flap technique reduces postoperative epidural fibrosis and leads to a favorable long-term prognosis. The L5-S1 interlaminar space on the operative side is exposed with use of a standard microsurgical approach, and the level is confirmed. The ligamentum flavum is held taut with use of tooth forceps, holding onto superficial layers, and a flap with its base on the lateral side is created. Initial separation is made at the midline (where the flavum is very thin) with use of a no.-15-blade scalpel. The flap is elevated by detaching the ligamentum flavum between the lower border of the L5 lamina and sacrum with use of a 1-mm Kerrison rongeur. The detachment of the ligamentum flavum is performed carefully, preserving the attachments on the lateral border. Having a thin base allows the flap to be elevated and rotated, and the flap thus can be tucked into the muscle above the facet joint. The nerve root is retracted, and discectomy is performed according to the location and size of the disc. After achieving good hemostasis, the ligamentum flavum flap is gently rotated back to its normal position. In most cases, the flap can be returned back to its original position without any gap and without any need for suture. Closure is performed in layers. Nonoperative treatment yields good pain relief in more than 80% of patients with disc herniation. However, if surgery is required, the primary concern for the surgeon is the prevention of postoperative scarring and fibrosis around the nerve root. Previous attempts to mitigate this potential complication have revolved around the placement of a subcutaneous fat graft over the nerve root; however, no firm evidence exists to support this technique. Synthetic materials such as expanded polytetrafluoroethylene, Adcon-L gel (Wright Medical Technologies), and sodium hyaluronate have also been utilized to prevent epidural scarring; however, the ligamentum flavum is a natural biological solution. Postoperative fibrosis may occur if there is a dead space as a result of the excision of the ligamentum flavum or due to inflammation. Restoration of native tissue anatomy with use of the ligamentum flavum technique can prevent such fibrosis, as has been reported previously. In addition to reducing scar formation, preserving the ligamentum flavum can make revision surgery (which is rarely required) safer, as there is less or no epidural fibrosis or nerve root scarring. Patients undergoing this procedure have shown good improvement in the Oswestry Disability Index (ODI) and a clinically notable reduction in visual analog scale (VAS) pain scores in the immediate postoperative period as well as on long-term follow-up. The chances of epidural fibrosis have been shown to be significantly decreased over long-term follow-up. Li et al. reported substantially lower VAS and ODI scores among patients who underwent the ligamentum flavum flap technique compared with a control group, as well as a significantly lower grade of epidural fibrosis at 6 months postoperatively2. In a similar study, Özay et al. highlighted significant clinical improvement and reduced chances of postoperative epidural fibrosis in 51 patients who underwent the ligamentum flavum flap technique3. Additionally, Li et al. showed that patient age and the area of the laminar space were the 2 important factors that determine the preservation of the ligamentum flavum, as the failure rate was significantly higher in elderly patients (>43.5 years) and those with small interlaminar space (<1.95 cm2). ODI and VAS scores were substantially better, and fibrosis formation, as assessed on computed tomography (CT) scans with intravenous iopamidol injection, was significantly reduced in patients with preserved ligamentum flavum4. Properly set up the operating microscope and fluoroscopy unit in order to ensure accurate starting points.Utilize minimal cautery at all levels of dissection.Hold the ligamentum flavum taut superficially while incising with use of a no.-15 scalpel.Detach the ligamentum flavum while safely preserving the attachments on the lateral border.Perform proper repositioning of the ligamentum flavum after achieving hemostasis. ODI = Oswestry Disability IndexVAS = visual analog scaleCT = computed tomographyLF = ligamentum flapSLRT = straight leg raise testAP = anteroposteriorMRI = magnetic resonance imagingASIS = anterior superior iliac spineCSF = cerebrospinal fluid.

Ultrasonic Bone Scalpel versus Conventional Technique for Thoracolumbar Spinal Decompression: A Prospective Randomized Controlled Trial.

Objective The purpose of the present study is to compare intraoperative blood loss, operating time, laminectomy time, hospital length of stay, and complications in thoracolumbar spinal decompression using ultrasonic bone scalpels (UBSs) with conventional procedures. Methods Forty-two patients who underwent decompressive laminectomy and pedicular screw fusion with a surgical level of 1-5 levels between February 1, 2020, and June 30, 2022, in a single institution were evaluated for eligibility, and 11 were excluded due to a history of spinal surgery ( n = 3), spinal tumor ( n = 3), and spinal infection ( n = 5). A total of 31 patients were randomly divided into the UBS group ( n =15) and the conventional group ( n =16). Intraoperative blood loss, operating time, laminectomy time, hospital length of stay, and complications were recorded. Results Intraoperative blood loss and laminectomy time were significantly lower in the UBS group (656.0 ± 167.6 ml, 54.5 ± 27.4 minutes, respectively) than in the conventional group (936.9 ± 413.2 ml, 73.4 ± 28.1 minutes, respectively). Overall operation time, hospital length of stay, and complications were all similar between the groups. Conclusion The UBS is a useful instrument for procedures performed near the dura mater or other neural tissue without excessive heat or mechanical injury. This device is recommended for various spinal surgeries in addition to high-speed burrs and Kerrison rongeurs.

Different C2 screw placement techniques with mobilization of the vertebral artery in high-riding vertebral artery cases: Cadaver dissection.

In neurosurgery, posterior approaches intended at the craniovertebral junction are frequently used. The most popular procedures for treating upper cervical instability are C1 lateral mass, C2 pedicle, and C1-C2 transarticular screw stabilization. Due to their proximity to neural structures and the presence of the high-riding vertebral artery (VA), these techniques are complicated. The risk of VA damage can be decreased by mobilizing the VA. Using cadaveric specimens in this study was aimed to demonstrate C2 pedicle and C1-C2 transarticular screw placement with VA mobilization and a novel C2 inferior corpus screw placement technique. In this study, twelve adult cadaveric specimens and two adult dry cadaveric C2 bones were used with the permission and decision of the University Research Ethics Committee. Colored silicone was injected into the arteries and veins of these twelve cadaveric specimens. Then, muscle dissection was performed stepwise, and the C2 vertebrae of the cadavers were revealed with a surgical microscope. Each specimen and entire stages of the dissections were recorded photographically. After cadaver dissections, screw placement was performed with three different techniques. Finally, radiological imaging was done with fluoroscopy. After dissection, the lateral mass of the C2 vertebra was observed, and lateral to it, the transverse process and foramen were detected with the help of a hook. Next, the posterior wall of the VA groove was removed using a 1 mm thin plate Kerrison rongeur until the VA loop could partially be observed the VA. This enables us to find the top of the loop of the VA and mobilize it inferiorly using a dissector. Following this step, the C1-2 transarticular, C2 pedicle, and the novel C2 inferior corpus screw placement can be performed safely by directly visualizing the artery. Due to the nearby neurologic and vascular structures, placing the C2 pedicle and C1-2 transarticular screw is a challenging procedure, especially in high-riding VA cases. However, it is possible to place the C2 pedicle, C1-2 transarticular, and novel C2 inferior corpus screw after the mobilization of the VA. This study aimed to show all of them together on a cadaver for the first time, to understand the anatomy of the C2 vertebra, and to use screw placement techniques to minimize the risk of complications.

Dural injury following elective spine surgery – A prospective analysis of risk factors, management and complications

Incidental dural tears being a familiar complication in spine surgery could result in dreaded postoperative outcomes. Though the literature pertaining to their incidence and management is vast, it is limited by the retrospective study designs and smaller case series. Hence, we performed a prospective study in our institute to determine the incidence, surgical risk factors, complications and surgical outcomes in patients with unintended durotomy during spine surgery over a period of one year. The overall incidence in our study was 2.3% (44/1912). Revision spine surgeries in particular had a higher incidence of 16.6%. The average age of the study population was 51.6 years. The most common intraoperative surgical step associated with dural tear was removal of the lamina, and 50% of the injuries were during usage of kerrison rongeur. The most common location of the tear was paramedian location (20 patients) and the most common size of the tear was about 1 mm-5mm (31 patients). We observed that the dural repair techniques, placement of drain and prolonged post-operative bed rest didnot significantly affect the post-operative outcomes. One patient in our study developed persistent CSF leak, which was treated by subarachnoid lumbar drain placement. No patients developed pseudomeningocele or post-operative neurological worsening or re-exploration for dural repair. Wound complications were noted in 4 patients and treated by debridement and antibiotics. Based on our study, we have proposed a treatment algorithm for the management of dural tears in spine surgery.

Use of Cannulated Reamers to Facilitate Thoracic Diskectomy Using a Minimally Invasive Retropleural Thoracotomy Approach-Surgical Technique.

The surgical treatment of symptomatic thoracic disk herniations is technically challenging. In the past decade, a minimally invasive retropleural thoracotomy approach has become more popular to treat this pathology. However, efficient bone removal to safely perform the diskectomy and spinal cord decompression is difficult with this technique because of the small incision size and long working distance in the thoracic cavity and the proximity of the compressed thoracic cord. To describe a novel surgical technique for performing a thoracic diskectomy using a minimally invasive lateral approach using cannulated reamers to facilitate bone removal. This technique was used in 7 consecutive patients who presented with thoracic myelopathy from a thoracic disk herniation. First, a standard lateral minimally invasive retropleural approach to the thoracic spine was performed. Partially threaded guide wires were placed in the posterior aspect of the vertebral bodies adjacent to the affected disk space, and sequential cannulated reamers were passed over the guidewires to perform partial corpectomies. The posterior annulus, posterior longitudinal ligament, and herniated disk material were then resected using Penfield dissectors and Kerrison rongeurs to complete the decompression. All 7 patients who underwent thoracic diskectomy using this approach had stable or improved neurologic function postoperatively. There were no complications related to the use of the cannulated reamer technique. The use of cannulated reamers provides a simple and efficient method for safe bone removal to facilitate minimally invasive thoracic diskectomy using a lateral approach. This is an easily reproducible technique using commonly available equipment.

Anterior Cervical Foraminotomy for Radiculopathy After Cervical Artificial Disc Replacement: Technique Description and Case Report.

Patients may occasionally have persistent or recurrent radicular symptoms after cervical artificial disc replacement (ADR) for cervical spondylotic radiculopathy. We describe our approach using anterior cervical foraminotomy (ACF) to provide symptom relief in such patients without the need to convert to a fusion or remove the ADR implant. Our operative technique for ACF after cervical ADR begins by starting at the lateral edge of the ADR at the superior end plate of the inferior vertebral body. The ipsilateral uncovertebral joint is drilled with a combination of a high-speed burr and diamond-coated burr to minimize the risk of injury to the vertebral artery. The neuroforamen is entered after drilling through the posterior aspect of the uncinate process. The exiting cervical nerve root should be directly visualized, and a Kerrison rongeur may be used to trace along the nerve root laterally to remove any remaining uncinate osteophyte or process. We queried our internal database for patients with recurrent or new radicular pain following cervical ADR who underwent ACF. Clinical characteristics and outcomes were reported. Five patients with recurrent radicular symptoms after ADR were reviewed. Two ACFs were performed at C5-6, and 2 were performed at C6-7. Four patients developed ipsilateral recurrent radicular symptoms, and only 1 patient developed contralateral new radicular symptoms. Three patients reported complete resolution of their new or recurrent radicular symptoms following ACF, and 2 patients reported only partial resolution. No patients required conversion to a fusion. In patients with recurrent symptoms of cervical spondylotic radiculopathy following ADR, ACF with uncovertebral joint resection can be used to provide direct foraminal decompression without the need for implant removal. This approach also preserves motion at the affected level, preserves cervical spinal stability, and prevents the need for spinal fusion. Patients with persistent or recurrent radicular symptoms after cervical ADR may achieve resolution of symptoms through a modified ACF technique.

Complete posterior cranial vault distraction osteogenesis to correct Chiari malformation type I associated with craniosynostosis.

Posterior vault distraction osteogenesis (PVDO) is an effective tool to increase intracranial volume and expand the posterior cranial fossa. During PVDO, the authors extended osteotomy posterior to the foramen magnum to fully expand the posterior cranial fossa. The aim of this study was to investigate the efficacy of complete PVDO in posterior fossa expansion and treatment of Chiari malformation type I (CM-I) in patients with craniosynostosis. Patients with craniosynostosis who had undergone complete PVDO between January 2012 and May 2020 were reviewed retrospectively. A coronal osteotomy extending to the foramen magnum was performed and the foramen magnum was decompressed by removing its posterior rim with a 1-mm Kerrison rongeur. Four distractor devices were placed and the vector of distraction was controlled from the posterior to the inferior-posterior direction, depending on the deformity. Changes in the intracranial volume, posterior cranial fossa area, and cerebellar tonsillar descent were measured after complete PVDO by using CT and MRI. A total of 11 patients with craniosynostosis and concurrent CM-I were included in the study. The mean age was 34.6 ± 24.0 months (continuous variables are expressed as the mean ± SD throughout). One patient had sleep apnea, which was consistent with CM-I, and another patient had a headache, which was nonspecific. The intracranial volume increased from 1179.6 ± 180.2 cm3 to 1440.6 ± 251.5 cm3 (p = 0.003; 24.5% increase compared to the preoperative volume). The posterior skull base area increased from 44.9 ± 19.3 cm2 to 72.7 ± 18.1 cm2 (p = 0.004). Cerebellar tonsillar descent decreased in all 11 patients after complete PVDO (preoperative: 10.8 ± 3.7 mm, postoperative: 2.7 ± 3.0 mm; p = 0.003). Among the 11 patients, 5 showed complete resolution of cerebellar tonsillar herniation. Complete PVDO can more efficiently expand the posterior cranial fossa, unlike conventional methods. Moreover, it helps to relieve cerebellar tonsillar herniation. Complete PVDO is a powerful tool to increase the intracranial and posterior fossa volumes in patients with craniosynostosis and concurrent CM-I.

ИССЛЕДОВАНИЕ ВЫЖИВАЕМОСТИ КЛЕТОК ДВУХ ВИДОВ АУТОЛОГИЧНЫХ КОСТНО-ПЛАСТИЧЕСКИХ МАТЕРИАЛОВ ПРИ ВЫПОЛНЕНИИ СПОНДИЛОДЕЗА

Objectives. To compare the survival rate of «bone chip» cells and native transplant automixture by evaluating the architectonics of cell membranes. Material and methods. Autograft in the form of a native graft automixture obtained using a «bone dust filtering device» and «bone chips» obtained using Kerrison rongeurs in 6 patients operated for degenerative diseases of the spine. The study was carried out using a flow cytometer by assessing the architectonics of cell membranes during the first three days. Results. The study of native transplant automixture and «bone chips» determined the dispersed state of the first graft and the latter, similar in its structure to the whole bone. The spectrograms analysis showed a heterogeneous composition of grafts, and in the case of native transplant automixture, the scatter was more pronounced. The increase in the number of cells during the first three days of the native transplant automixture is probably associated with the elimination of contact inhibition of their proliferation and the release of osteoinductive factors from the bone matrix. The number of necrotic cells was higher in the native transplant automixture, which is due to the rough method of its preparation, however, this number was not statistically significant compared to the number of necrotic cells in the «bone chips». Despite the combined thermal and mechanical impact, the survival of the cell component in both cases made up more than 98.0% without any statistical significance in comparison between the two types of transplants (p&gt;0.05). Conclusions. The high survival rate of the cellular component of both types of autografts indicates that the osteogenic potential does not depend on the method of their preparation.

Two-Level Minimally Invasive Lumbar Laminectomy and Foraminotomy: 2-Dimensional Operative Video.

Minimally invasive lumbar laminectomies utilize tubular retractors to minimize tissue disturbance, blood loss, and hospital length of stay compared to open operations. Here, we highlight the operative treatment of a 68-yr-old male entailing a 2-level minimally invasive lumbar laminectomy and foraminotomy at L2-L3 and L3-L4. The patient initially presented with symptoms of treatment-refractory lower extremity numbness and limited ambulation. His imaging demonstrated coronal scoliosis and severe lumbar central and foraminal stenosis at L2-L3 and L3-L4, with enlarged spinous processes, laminae, and facets. The patient consented to the procedure and publication of their image. The operation proceeded with the patient in a prone position with paramedian dissection to the lamina through a minimally invasive tubular retractor. Laminectomies and foraminotomies were performed at each level with high-speed drill and a Kerrison rongeur, with care to identify and protect the relevant spinal nerve roots. Postoperatively, the patient reported significantly reduced numbness and improved ambulation, with a well-healed surgical incision notably smaller than those produced in an open operation.

Dural Tear During Thoracic Laminectomy Using Craniotome With Footplate Attachment.

Laminectomy can be accomplished using the craniotome with a footplate attachment, and the technique has been advanced as a superior alternative to using a high-speed drill-driven burr and Kerrison rongeurs. Laminectomy can be accomplished more rapidly and with less bone destruction, an advantage when planning laminoplasty. There is, however, scant literature describing complications of dural laceration using this technique. A 48-year-old male underwent T7-10 laminectomy for resection of an intramedullary spinal cord tumor. During the upward cut of the hemi-lamina at T7-9, a dural laceration occurred that proved not amenable to direct suture closure. The dural was closed with a dural patch placed along the inner surface of the dura and a fat graft on the outer surface with adjunctive use of a lumbar drain. While the footplate laminectomy technique has merits touted in prior publications, including the ability to open the spinal canal quickly at numerous levels and an enhanced ability to achieve an osteoplastic laminoplasty, surgeons should be cognizant of the risk of associated dural laceration. We believe that it is important to emphasize that the initial placement of the lip of the footplate must be well-seated under the inferior aspect of the lowest lamina and over the ligamentum flavum and that the footplate should not be directed beyond the border of the laminae and facet, as this can result in dura and root injury.

Robotic transmaxillary approach to the lateral infratemporal fossa: A preclinical cadaveric study using a next-generation single-port robotic system.

Robotic transmaxillary skull base surgery has been described using multiport systems. This cadaveric study investigates the feasibility of transmaxillary skull base surgery using a next-generation robot. An extended Caldwell-Luc antrostomy, measuring 3.3 cm by 4.0 cm, was performed in 15 min using a Kerrison rongeur and the robotic endoscope. A single-port, robotic system (da Vinci Sp®, Intuitive Surgical, Inc, Sunnyvale, CA, USA) was then deployed throught the extended Caldwell-Luc approach and provided sufficient reach, visualization, and maneuverability to work within the pterygopalatine fossa (PPF) and the infratemporal fossa (ITF) using three surgical instruments. The ITF dissection was easiest with two instruments using the third instrument to retract the muscles of mastication. This study demonstrates the feasibility of single-port robotic transmaxillary approaches to the lateral ITF. Using a single-port robotic system, the operating surgeon can for the first time work in the PPF and ITF using two functional arms for tumor dissection and a third to retract.

Endoscopic endonasal skull base surgery during the COVID-19 pandemic: A developing country perspective.

Background: Although primarily a respiratory disorder, the coronavirus pandemic has paralyzed almost all aspects of health-care delivery. Emergency procedures are likely continuing in most countries, however, some of them raises certain concerns to the surgeons such as the endoscopic endonasal skull base surgeries. The aim of this study is to present the current situation from a developing country perspective in dealing with such cases at the time of the COVID-19 pandemic.Methods: A cross-sectional analytical survey was distributed among neurosurgeons who performed emergency surgeries during the COVID-19 pandemic in Cairo, Egypt, between May 8, 2020, and June 7, 2020. The survey entailed patients’ information (demographics, preoperative screening, and postoperative COVID-19 symptoms), surgical team information (demographics and postoperative COVID-19 symptoms), and operative information (personal protective equipment [PPE] utilization and basal craniectomy).Results: Our survey was completed on June 7, 2020 (16 completed, 100% response rate). The patients were screened for COVID-19 preoperatively through complete blood cell (CBC) (100%), computed tomography (CT) chest (68.8%), chest examination (50%), C-reactive protein (CRP) (50%), and serological testing (6.3%). Only 18.8% of the surgical team utilized N95 mask and goggles, 12.5% utilized face shield, and none used PAPRs. Regarding the basal craniectomy, 81.3% used Kerrison Rongeur and chisel, 25% used a high-speed drill, and 6.3% used a mucosal shaver. None of the patients developed any COVID-19 symptoms during the first 3 weeks postsurgery and one of the surgeons developed high fever with negative nasopharyngeal swabs.Conclusion: In developing countries with limited resources, preoperative screening using chest examination, CBC, and CT chest might be sufficient to replace Reverse transcription polymerase chain reaction. Developing countries require adequate support with screening tests, PPE, and critical care equipment such as ventilators.

P30. Safe and improved spinal surgery using a new device in multiple indications

BACKGROUND CONTEXT Spinal procedures often require the removal of bony tissues to prevent nerve compression and reduce pain. In order to reach difficult-access spinal regions such as the foramen, the surgeon is often required to drill (or otherwise remove) through healthy supporting bone structures, therefore increasing the risk of spinal instability. PURPOSE This study describes the authors' experience with a recently developed, FDA-approved, curved-at-the-tip drill-like device, designed to provide efficient bone removal from difficult-access areas. The device is shielded on one side of the tip in order to improve safety and reduce the risk of complications. STUDY DESIGN/SETTING Multi-center retrospective study and surgeon questionnaire analysis. PATIENT SAMPLE Device-use patterns were extracted from 103 lumbar foraminotomies, 53 cervical osteophyte removals and 143 transforaminal lumbar interbody fusion (TLIF) procedures conducted using the device and 66 comparable control TLIF procedures conducted by the same surgeon group used as a control group. OUTCOME MEASURES Device-related dural tear rate, surgeon assessment of the procedure, duration of device use. For the TLIF procedures, OR time and length of stay were also compared with the control group. METHODS The rate of device-related dural tears was calculated from 1,116 safety records of procedures conducted using the device and compared with literature rates of traditional-tools device-related tears. Surgeon assessment was obtained using questionnaires at the end of each procedure. The duration of device-use, length of procedure and other operative and postoperative parameters were extracted from procedure records and reviewed where available. RESULTS The device-related dural tear rate was 0.3% (three tears in 1,116 procedures). This rate is significantly lower than the device-related tear rate of 2.9% associated with the Kerrison rongeur and high-speed drill published in a prior literature review. Surgeon satisfaction rate was 94% and sufficient bone volume reduction was reported in 95% of the procedures. Surgery time reduction was the most common comment in surgeon questionnaires. In some cases, of multi-level complicated fusions, the time reduction was estimated as several hours. Lumbar foraminotomy using the device required, on average, 2 minutes/foramen. In some of the cases, the device enabled the surgeon to avoid a spinal fusion as the improved access eliminated the need for excessive bone removal. Cervical osteophyte removal required, on average, three minutes, and in the majority of the cases enabled the surgeons to avoid additional level discectomy or corpectomy. TLIF procedures required on average 10 minutes less than control procedures with a 0.5 days reduction in length-of-stay. The device was successfully used in both open and minimal invasive settings without a significant difference between settings. CONCLUSIONS The device is safe and effective for performing spinal surgery in multiple indications. Procedure time reduction was noted as the most significant advantage by the surgeons. FDA DEVICE/DRUG STATUS Dreal (Carevature Medical Ltd.) (Approved for this indication)

Letter: Rongeurs, Neurosurgeons, and COVID-19: How Do We Protect Health Care Personnel During Neurosurgical Operations in the Midst of Aerosol-Generation From High-Speed Drills?

To the Editor: A neurosurgical team, including 10 neurosurgical nurses and 4 other hospital staff, were infected with the novel coronavirus by a neurosurgical patient who was admitted for an elective trans-sphenoidal operation.1,2 This neurosurgery patient initially had no symptoms or signs of respiratory tract infection before the operation and he only developed fever 3 d after the operation. He was subsequently diagnosed with coronavirus disease 2019 (COVID-19) 5 d after his trans-sphenoidal surgery. COVID-19 is an infectious disease that can be transmitted via droplets or aerosols to the respiratory tract. The viral load is high along the respiratory tract mucosa, including the nasal cavity, nasopharynx, and oropharynx.3 The viral ribonucleic acid (RNA) can be detected in the sputum, saliva, as well as in the serum.3-6 Medical staff is at high risk of exposure to the virus. It was reported that up to 29% of the initial cohort of the confirmed infected novel coronavirus cases were medical staff.7 Up to date, 3.8% of the confirmed COVID-19 cases were health care personnel (HCP) and 14.8% of their conditions were severe or critical.8 Overall, the mortality rate is around 4.1% (ranging from 0.25% to 8%).9 At the same time, the majority (up to 81%) of the cases have only mild symptoms.8 In fact, the majority of the patients had minimal or no symptoms during the incubation period in the first 3 to 6 d.5 Yet these asymptomatic or “presymptomatic” contacts were reported to be able to transmit the virus.10 Aerosol-generating medical procedures (AGMP) are any procedures performed on patients that can produce aerosols of various sizes.6 Hence, it is recommended that full personal protective equipment (PPE) should be worn during AGMP, such as intubation, for confirmed or suspected COVID-19. After intubation, the operating theater (OT) staff, including anesthetists, nurses, and other supporting staff, would usually take off some of their protective gear such as face shield, eye protection goggles, gloves, and long-sleeved waterproof gown. Some of them might also take off their masks with high filtration such as the particulate respirators. For neurosurgery, one might overlook the aerosol-generating property of powered instruments such as the use of high-speed drills.11 These are commonly used tools for craniotomy and other neurosurgical procedures. Bone scattering from temporal bone drilling can be up to 3.5 feet.12 Powered instruments had been shown to generate blood-containing aerosols with a concentration of hemoglobin detected in the ambient air.11 Viruses, including human immunodeficiency virus-1 (HIV-1), was demonstrated to be viable in the aerosols generated by surgical power instruments.13 For the neurosurgical operations requiring the dissection of the nasopharyngeal mucosa such as the trans-sphenoidal excision of pituitary tumor, the risk of “aerosolizing” the virus is very high with the use of high-speed drills in the nasal cavity. Nonurgent trans-sphenoidal operations should be suspended during this pandemic. For patients indicated for urgent or semiurgent trans-sphenoidal decompression, eye protection such as goggles should be worn by the neurosurgeons and the OT staff in view of the potential risks of transcorneal transmission. Nonpowered tools such as septum rongeur and Kerrison rongeur should be used to open the sphenoidal sinus and the sella floor instead of using high-speed drills. The Wuhan Blood Center and blood banks in the Hubei province started to test blood donations for SARS-CoV-2 RNA on February 10.4 As the novel coronaviral RNA can be present in the blood of confirmed or suspected asymptomatic contacts, these aerosols generated during neurosurgical procedures are potentially infectious. Hudson Brace and other hand drills can be used during emergency operations when the COVID-19 infection status was unknown and when the OT staff might not have full airborne PPE. For suspected COVID-19 cases requiring elective neurosurgical operations, COVID-19 infective status should be checked before the surgery. If the results are negative, then airborne precautions would not be required and the use of PPE can be rationalized. Overall, we recommend our fellow neurosurgeons and trainees to uphold the traditional craft of using hand drills and rongeur in order to minimize aerosol generation from the neurosurgical powered instruments during the COVID-19 pandemic. Disclosures The authors have no personal, financial, or institutional interest in any of the drugs, materials, or devices described in this article.

Optic canal decompression in patients with vision reduction due to tumour growth in optic canal: A technical note

Improvement of the vision is one of the main goals in skull base meningiomas compressing the optic nerve (ON) in optic canal (OC). Extracranial drilling of anterior clinoid process with extradural optic canal decompression has been demonstrated in anterior clinoid meningioma surgery. Extensive drilling of anterior clinoid has however some morbidity. Here we demonstrate the technical aspects of intradural opening of optic canal using Kerrison rongeur. This technique is effective and has no additional morbidity.

Quantitative and qualitative analyses of spinal canal encroachment during cervical laminectomy using the kerrison rongeur versus High-Speed burr

Background: Several cervical laminectomy techniques have been described. One commonly used method involves making bilateral trough laminotomies using either a Kerrison rongeur or a high speed burr, and then removing the lamina en-bloc. Alternatively, some surgeons prefer to thin the lamina with the burr, and then remove the lamina in a piecemeal fashion using Kerrison rongeurs. Some surgeons have warned against the potential risk of iatrogenic spinal cord injury from inserting the Kerrison footplate into a stenotic canal. We aim to quantify the amount of canal encroachment for various methods of cervical laminectomies. Methods: Three attending spine surgeons and two fellows each performed laminectomies using C5 sawbones models. The canal was completely filled with modeling putty to simulate a stenotic spinal cord. Bilateral trough laminotomies were performed using a 1 mm Kerrison, a 2 mm Kerrison, and a 3 mm matchstick high-speed burr. Piecemeal laminectomies were performed with a 2 mm Kerrison. A blinded spine surgery fellow performed all quantitative measurements. Three blinded researchers qualitatively ranked the amount of “canal encroachment”. Results: The average canal encroachment was 0.50 ± 0.45mm for the burr, 1.37 ± 0.68 mm for the 1 mm Kerrison, and 1.47 ± 0.37 mm for the 2 mm Kerrison (p = .002). There was a statistically significant difference between the burr and 1 mm Kerrison (p = .01) and between the burr and the 2 mm Kerrison (p = .001). There was no statistical difference between the 1 mm and 2 mm Kerrison (p = .78). The mean rank of the burr group, the Kerrison rongeur group, and the piecemeal group were 1.41, 1.94, and 2.65, respectively, on an ordinal scale of 1–3. Conclusion: When performing a trough laminotomy, the high-speed burr results in less canal encroachment compared to 1 mm or 2 mm Kerrison rongeurs. In the setting of a stenotic spinal canal, spine surgeons should consider using the burr to perform laminectomy to minimize the degree of canal encroachment.

Origins of eponymous instruments in spine surgery.

Every day, spine surgeons call for instruments named after surgical pioneers. Few know the designers or the histories behind their instruments. In this paper the authors provide a historical perspective on the Penfield dissector, Leksell rongeur, Hibbs retractor, Woodson elevator, Kerrison rongeur, McCulloch retractor, Caspar pin retractor system, and Cloward handheld retractor, and a biographical review of their inventors. Historical data were obtained by searching the HathiTrust Digital Library, PubMed, Google Scholar, Google Books, and Google, and personal communications with relatives, colleagues, and foundations of the surgeon-designers. The authors found that the Penfield dissectors filled a need for delicate tools for manipulating the brain and that the Leksell rongeur increased surgical efficiency during war-related laminectomies. Hibbs' retractor facilitated his spine fusion technique. Woodson was both a dentist and a physician whose instrument was adopted by spine surgeons. Kerrison rongeurs were developed in otology to decompress bone near the facial nerve. The McCulloch, Caspar, and Cloward retractors helped improve exposure during the emergence of new techniques, i.e., microdiscectomy and anterior cervical discectomy and fusion. The histories behind these eponymous instruments remind us that innovation sometimes begins in other specialties and demonstrate the role of innovation in improving patient care.

Microsurgical Treatment of Bowhunter's Syndrome: 3-Dimensional Operative Video.

We present the case of a 56-yr-old previously healthy male who presented with an approximately 1-yr history of intermittent dizziness, near syncope, and holocephalic headaches when turning his head to the left side for a prolonged period of time. He had a distant history of a previous anterior cervical discectomy and fusion at the C6-7 level. He was neurologically intact. Static, dynamic, and vascular imaging confirmed hypoplasia of the right vertebral artery and dominance of the left vertebral artery that completely filled the posterior circulation. Dynamic imaging confirmed compression of the left vertebral artery just above the C5-6 disc space on full head rotation to the left. After an anterior cervical exposure, we dissected lateral to the C5-6 disc space to the transverse process. The anterior tubercle was identified, and a Doppler ultrasound was used to insonate the vertebral artery above the level of compression. The anterior wall of the transverse foramen was thinned with a high-speed drill under constant irrigation and Kerrison rongeurs used to expose the vertebral artery at the site of compression. Importantly, the fibrotic band at, above, and below the level of compression was also dissected and removed. The patient tolerated the procedure well, and was discharged from the hospital 2 d after surgery with no neurological deficits and with complete relief of his preoperative symptoms. Because his symptoms completely resolved and have not recurred, no postoperative imaging was performed. The etiology, presentation, and microsurgical treatment of this rare disease are discussed.All appropriate patient consents were obtained for this submission.© 2017 Department of Neurosurgery, Emory University Hospital. Used with permission.All Figures used with permission as above.

Suitability of Administrative Databases for Durotomy Incidence Assessment: Comparison to the Incidence Associated With Bone-Removal Devices, Calculated Using a Systemic Literature Review and Clinical Data.

Durotomy is a major complication of spinal surgery, potentially leading to additional clinical complications, longer hospitalization, and increased costs. A reference durotomy incidence rate is useful for the evaluation of the safety of different surgical aspects. However, the literature offers a wide range of incidence rates, complicating this comparison. Theoretically, a reference incidence value can be extracted from administrative databases, containing a large number of procedures. However, it is suspected that these databases suffer from underreporting of complications. This study aims to evaluate durotomy incidence using several large-scale databases and to assess the ability to use it as a reference by comparison to durotomy incidences directly associated with 4 bone removal devices, including the commonly used high-speed drill. Durotomy overall incidence was estimated from several administrative databases using different methods in order to achieve minimal and maximal estimations. Durotomy incidences for 3 bone removal devices were derived using literature meta-analysis, and the incidence for the fourth device was calculated using clinical data. The incidence range of durotomy according to the databases was 2.8-3.5%. The calculated incidence of durotomy for the studied devices was 0.4-2.91%. The highest rate, 2.91%, is associated with the commonly used high-speed drill combined with Kerrison Rongeur and bone punches. Since bone-removal devices are just one of the possible causes of dural tears, the general incidence is expected to be higher than the incidence associated with the devices, yet even the maximal estimation, 3.5%, was only slightly higher, suggesting that the speculation of underreporting of dural tears to these databases is probably true, as also supported by the mostly higher incidences reported in the literature. Hospital administrative databases seem to show a lower-than-reasonable incidence of durotomy, suggesting possible underreporting. Researchers should therefore use this tool with caution. Reduction of the absolute durotomy incidence by approximately 2.5% can be achieved by improving the safety of bone-removal devices.