Piezosurgery-, neuroendoscopy-, and neuronavigation-assisted intracranial approach for removal of a recurrent petrous apex cholesteatoma: technical note

Piezoelectric ear surgery: a systematic review

BACKGROUND

The piezoelectric instrument (PEI) offers a novel technique for bone removal in ear surgery with a combination of micro-oscillation and cavitation. The aim of this review is to explore the advantages, disadvantages, and limitations of this instrument in comparison to the drill.

MATERIALS AND METHODS

We conducted a search of PubMed/MEDLINE and Google Scholar in accordance with the PRISMA recommendations. The primary selection included all studies reporting on the use of PEI in ear surgery or its effect on the inner ear. Only studies with a control group were included in the secondary selection.

RESULTS

The first search identified 49 studies between 2003 and 2022. These reported on a total of 1162 ear operations, during which PEI was used for various indications. Most data were based on uncontrolled retrospective studies or case reports (76%). Only one of the five controlled clinical studies was prospective and randomized. The advantages of PEI weighed against its limitations and disadvantages were critically analyzed in comparison to the drill.

CONCLUSION

Piezoelectric surgery is an innovative and promising surgical technique in the temporal bone. PEI appears to enable safer and more precise bone removal in close proximity to soft tissue when compared to the drill. The slower bone removal and cost factors represent current limitations to its wider use in ear surgery.

Use of BoneScalpel Ultrasonic Bone Dissector in Anterior Clinoidectomy and Posterior Fossa Surgery: Technical Note

BackgroundFirst popularized by Dolenc, anterior clinoidectomies were performed with rongeurs, before the adoption of modern high-speed drills. We describe a novel application of the piezoelectric BoneScalpel™ in anterior skull base and posterior fossa surgeries. In the literature, to date, there are no mentions of anterior clinoidectomies performed with piezosurgical devices.MethodsWe reported a total of 12 patients, 8 affected by posterior fossa tumors and 4 treated for anterior skull base oncologic and vascular pathologies. This study aims to assess the safety and efficacy of the piezoelectric osteotomy in skull base and posterior fossa surgeries. In all patients, an ultrasonic bone dissector (BoneScalpel™ - Misonix) was used to perform the anterior clinoidectomy (AC) and craniotomy.ResultsA successful clinoidectomy was performed in 4 out of 12 patients (33.3%). We did not notice any heat damage to the surrounding soft tissue in critical areas such as paraclinoid structures. We documented only one durotomy in an oncologic patient, while no lesions of SSS or TS were detected.We recorded only a slightly increased surgery duration in the PIEZOSURGERY® and BoneScalpel™ group, compared to standard surgery with an osteotome to perform craniotomies, but no time difference in performing the clinoidectomy between BoneScalpel™ and a conventional high-speed drill.ConclusionWe report the first experience with piezosurgery for anterior clinoidectomy. There is no time difference in performing the clinoidectomy between BoneScalpel™ and a conventional high-speed drill, and this is an undoubted advantage in critical contexts such as clinoid-paraclinoid surgeries, where the risk of dural sinuses tears is common.

Surgical management of petrous apex cholesteatomas in the pediatric population: A systematic review

Background:

Cholesteatomas are growths of squamous epithelium that can form inside the middle ear and mastoid cavity and damage nearby structures causing hearing loss when located at the petrous apex. The primary goal of petrous apex cholesteatoma resection is gross total removal with tympanoplasty and canal-wall up or canal-wall down tympanomastoidectomy. At present, there is no definitive surgical approach supported by greater than level 4 evidence in the literature to date.

Methods:

A systematic review was conducted utilizing PubMed, Embase, and Scopus databases. Articles were screened and selected to be reviewed in full text. The articles that met inclusion criteria were reviewed for relevant data. Data analysis, means, and standard deviations were calculated using Microsoft Excel.

Results:

After screening, five articles were included in the systematic review. There were a total of eight pediatric patients with nine total cholesteatomas removed. Conductive hearing loss was the most common (77%) presenting symptom. Perforations were noted in seven ears (86%). Recurrence was noted in 50% of patients with an average recurrence rate of 3.5 years (SD = 1.73). Average length of follow-up was 32.6 months (SD = 21.7). Canal-wall up was the most utilized technique (60%) and there were zero noted surgical complications. Five of the seven (71%) patients that experienced hearing loss from perforation noted improved hearing.

Conclusion:

Due to its rarity, diagnostic evaluation and treatment can vary. Further, multi-institutional investigation is necessary to develop population-level management protocols for pediatric patients affected by petrous apex cholesteatomas.

[Piezoelectric ear surgery: a systematic review. German version]

BACKGROUND

The piezoelectric instrument (PEI) offers a novel technique for bone removal in ear surgery with a combination of micro-oscillation and cavitation. The aim of this review is to explore the advantages, disadvantages, and limitations of this instrument in comparison to the drill.

MATERIALS AND METHODS

We conducted a search of PubMed/MEDLINE and Google Scholar in accordance with the PRISMA recommendations. The primary selection included all studies reporting on the use of PEI in ear surgery or its effect on the inner ear. Only studies with a control group were included in the secondary selection.

RESULTS

The first search identified 49 studies between 2003 and 2022. These reported on a total of 1162 ear operations, during which PEI was used for various indications. Most data were based on uncontrolled retrospective studies or case reports (76%). Only one of the five controlled clinical studies was prospective and randomized. The advantages of PEI weighed against its limitations and disadvantages were critically analyzed in comparison to the drill.

CONCLUSION

Piezoelectric surgery is an innovative and promising surgical technique in the temporal bone. PEI appears to enable safer and more precise bone removal in close proximity to soft tissue when compared to the drill. The slower bone removal and cost factors represent current limitations to its wider use in ear surgery.

Freehand Stereotactic Image-Guidance Tailored to Neurotologic Surgery

Hypothesis: The use of freehand stereotactic image-guidance with a target registration error (TRE) of μ_TRE + 3σ_TRE < 0.5 mm for navigating surgical instruments during neurotologic surgery is safe and useful. Background: Neurotologic microsurgery requires work at the limits of human visual and tactile capabilities. Anatomy localization comes at the expense of invasiveness caused by exposing structures and using them as orientation landmarks. In the absence of more-precise and less-invasive anatomy localization alternatives, surgery poses considerable risks of iatrogenic injury and sub-optimal treatment. There exists an unmet clinical need for an accurate, precise, and minimally-invasive means for anatomy localization and instrument navigation during neurotologic surgery. Freehand stereotactic image-guidance constitutes a solution to this. While the technology is routinely used in medical fields such as neurosurgery and rhinology, to date, it is not used for neurotologic surgery due to insufficient accuracy of clinically available systems. Materials and Methods: A freehand stereotactic image-guidance system tailored to the needs of neurotologic surgery-most importantly sub-half-millimeter accuracy-was developed. Its TRE was assessed preclinically using a task-specific phantom. A pilot clinical trial targeting N = 20 study participants was conducted (ClinicalTrials.gov ID: NCT03852329) to validate the accuracy and usefulness of the developed system. Clinically, objective assessment of the TRE is impossible because establishing a sufficiently accurate ground-truth is impossible. A method was used to validate accuracy and usefulness based on intersubjectivity assessment of surgeon ratings of corresponding image-pairs from the microscope/endoscope and the image-guidance system. Results: During the preclinical accuracy assessment the TRE was measured as 0.120 ± 0.05 mm (max: 0.27 mm, μ_TRE + 3σ_TRE = 0.27 mm, N = 310). Due to the COVID-19 pandemic, the study was terminated early after N = 3 participants. During an endoscopic cholesteatoma removal, a microscopic facial nerve schwannoma removal, and a microscopic revision cochlear implantation, N = 75 accuracy and usefulness ratings were collected from five surgeons each grading 15 image-pairs. On a scale from 1 (worst rating) to 5 (best rating), the median (interquartile range) accuracy and usefulness ratings were assessed as 5 (4-5) and 4 (4-5) respectively. Conclusion: Navigating surgery in the tympanomastoid compartment and potentially in the lateral skull base with sufficiently accurate freehand stereotactic image-guidance (μ_TRE + 3σ_TRE < 0.5 mm) is feasible, safe, and useful. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03852329.

Evolution and Stagnation of Image Guidance for Surgery in the Lateral Skull: A Systematic Review 1989-2020

Objective: Despite three decades of pre-clinical and clinical research into image guidance solutions as a more accurate and less invasive alternative for instrument and anatomy localization, translation into routine clinical practice for surgery in the lateral skull has not yet happened. The aim of this review is to identify challenges that need to be solved in order to provide image guidance solutions that are safe and beneficial for use during lateral skull surgery and to synthesize factors that facilitate the development of such solutions. Methods: Literature search was conducted via PubMed using terms relating to image guidance and the lateral skull. Data extraction included the following variables: image guidance error, imaging resolution, image guidance system, tracking technology, registration method, study endpoints, clinical target application, and publication year. A subsequent search of FDA 510(k) database for identified image guidance systems and extraction of the year of approval, intended use, and indications for use was performed. The study objectives and endpoints were subdivided in three time phases and summarized. Furthermore, it was analyzed which factors correlated with the image guidance error. Factor values for which an error ≤0.5 mm (μ_error + 3σ_error) was measured in more than one study were identified and inspected for time trends. Results: A descriptive statistics-based summary of study objectives and findings separated in three time intervals is provided. The literature provides qualitative and quantitative evidence that image guidance systems must provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial application during surgery in the lateral skull. Spatial tracking accuracy and precision and medical image resolution both correlate with the image guidance accuracy, and all of them improved over the years. Tracking technology with accuracy ≤0.05 mm, computed tomography imaging with slice thickness ≤0.2 mm, and registration based on bone-anchored titanium fiducials are components that provide a sufficient setting for the development of sufficiently accurate image guidance. Conclusion: Image guidance systems must reliably provide an accuracy ≤0.5 mm (μ_error + 3σ_error) for their safe and beneficial use during surgery in the lateral skull. Advances in tracking and imaging technology contribute to the improvement of accuracy, eventually enabling the development and wide-scale adoption of image guidance solutions that can be used safely and beneficially during lateral skull surgery.

Role of endoscopy in lateral skull base approaches to the petrous apex

OBJECTIVE

The aim of this article is to study the role and advantages of combined microscopic/endoscopic procedures or exclusive endoscopic approaches in the treatment of petrous apex pathologies.

METHODS

The study was designed as a retrospective case series analysis. We included patients affected by pathologies of the petrous apex, who underwent microscopic/endoscopic-assisted or exclusive endoscopic procedures. Patient and pathology characteristics and surgical data (focusing on the involvement of the internal carotid artery (ICA) and facial nerve by the disease) were collected. Residual disease, detected through the endoscopic check, and the feasibility of endoscopic residual tumor removal were also evaluated. Finally, facial nerve and hearing functions were assessed pre- and postoperatively.

RESULTS

The records of 75 patients undergoing lateral skull base surgery for petrous apex lesions, from May 2009 to March 2019, were collected. In 17 out of 75 patients, an exclusive endoscopic procedure was possible. The remaining 58 patients underwent a combined microscopic/endoscopic approach. In 15 cases, residual disease was found and removed endoscopically at the end of the microscopic procedure; in eight cases, the residual disease was medial and/or inferior to the horizontal segment of the ICA, while in two cases, it was located in the fundus of the internal auditory canal. In five cases, it involved the labyrinthine segment of the facial nerve.

CONCLUSION

Petrous apex surgery remains a traditional microscopic-based surgery, but the recent advent of endoscopic surgery has permitted an improvement in radicality minimizing the manipulation of neurovascular structures.