Application of ultrasonic bone curette in endoscopic endonasal skull base surgery: technical note

Specialised Surgical Instruments for Endoscopic and Endoscope-Assisted Neurosurgery: A Systematic Review of Safety, Efficacy and Usability

While there have been great strides in endoscopic and endoscope-assisted neurosurgical approaches, particularly in the treatment of deep-sited brain and skull base tumours, the greatest technical barrier to their adoption has been the availability of suitable surgical instruments. This systematic review seeks to identify specialised instruments for these approaches and evaluate their safety, efficacy and usability. Conducted in accordance with the PRISMA guidelines, Medline, Embase, CENTRAL, SCOPUS and Web of Science were searched. Original research studies that reported the use of specialised mechanical instruments that manipulate tissue in human patients, cadavers or surgical models were included. The results identified 50 specialised instruments over 62 studies. Objective measures of safety were reported in 32 out of 62 studies, and 20 reported objective measures of efficacy. Instruments were broadly safe and effective with one instrument malfunction noted. Measures of usability were reported in 15 studies, with seven reporting on ergonomics and eight on the instruments learning curve. Instruments with reports on usability were generally considered to be ergonomic, though learning curve was often considered a disadvantage. Comparisons to standard instruments were made in eight studies and were generally favourable. While there are many specialised instruments for endoscopic and endoscope-assisted neurosurgery available, the evidence for their safety, efficacy and usability is limited with non-standardised reporting and few comparative studies to standard instruments. Future innovation should be tailored to unmet clinical needs, and evaluation guided by structured development processes.

Novel Application of an Ultrasonic Bone Aspirator for Endoscopic Modified Medial Maxillectomy

Background

Endoscopic modified medial maxillectomy (EMMM) is a surgical technique developed to approach maxillary sinus lesions, such as papilloma and postoperative maxillary cyst, while preserving the postoperative nasal morphology and nasal function. In this technique, a diamond burr is used to remove the bone, which may damage adjacent soft tissue. We developed EMMM using an ultrasonic bone aspirator (UBA) instead of a conventional diamond burr. The purpose of this study was to clarify the effectiveness of the UBA in EMMM in comparison to the conventional diamond burr technique in terms of operative time, intraoperative complications, postoperative symptoms, and recurrence.

Methods

The medical records of all patients who underwent EMMM at Toyama University Hospital between June 2014 and December 2021 were reviewed. Patients who met the inclusion criteria were separated into Group 1, in which the UBA was used for EMMM, and Group 2, in which a drill with a diamond burr was used. Data on patient demographics, operation time, frequency of intraoperative complications and postoperative symptoms, and recurrence were statistically compared between the two groups.

Results

There were no significant differences between the two groups in the patient demographic data, operative time, postoperative symptoms, or frequency of recurrence. The frequency of intraoperative damage to adjacent soft tissues was significantly lower in patients who underwent EMMM with the UBA in comparison to those who underwent EMMM with a conventional diamond burr.

Conclusion

The application of the UBA to EMMM can improve surgical safety and facilitate surgical procedures.

Drilling Speed and Bone Temperature of a Robot-assisted Ultrasonic Osteotome Applied to Vertebral Cancellous Bone

STUDY DESIGN

An experimental investigation of a robot-assisted ultrasonic osteotome applied to vertebral cancellous bone.

OBJECTIVE

The aim of this study was to investigate the effect of various ultrasonic parameter settings on temperature in the drilling site and penetration time and determine the most suitable parameters for efficient and safe robot-based ultrasonically assisted bone drilling in spinal surgery.

SUMMARY OF BACKGROUND DATA

A robot-assisted ultrasonic osteotome device may be safe and effective for spinal drilling.

METHODS

Sixty specimens of bovine vertebral cancellous were randomly assigned to one of six groups, which varied by mode of ultrasonic vibration (L-T and L) and feed rate (one percent [0.8 mm/s], two percent [1.6 mm/s], and three pecent [2.4 mm/s]). Maximum temperature in the drilling site and penetration time was recorded.

RESULTS

Maximum temperature in the drilling site decreased as output power increased for L-T and L modes, was significantly lower for L-T compared to L mode at each feed rate and power setting, was significantly different at feed rates of 1.6 mm/s versus 0.8 mm/s and 2.4 mm/s versus 0.8 mm/s for L-T mode at an output power of 60 W and 84 W, but was not influenced by feed rate for L mode. Penetration time did not significantly improve as output power increased for both L-T and L modes, was significantly decreased with increased feed rates, but was not significantly different between L-T and L modes.

CONCLUSION

The optimal parameters for applying a robot-assisted ultrasonic osteotome to vertebral cancellous bone are L-T mode, maximum output power of 120 W, and maximum feed rate of 2.4 mm/s.Level of Evidence: 4.

Surgical removal of orbital tumors by orbital approach using ultrasonic surgical system SONOPET®

Purpose: Orbital tumor surgery can be challenging when the tumor is located in a very narrow surgical field and close to important structures, such as nerves or extraocular muscles that can be damaged during surgery. Advances in technology and special surgical techniques help to avoid such damage. We describe our experience using SONOPET® ultrasonic surgical aspirator to remove 12 different orbital tumors that were difficult to treat due to their poorly defined borders, adhesions, or location.Methods: This is a retrospective case series that describes 12 operations that occurred between March 2016 to December 2018 using an ultrasonic device to debulk or remove orbital tumors. Different approaches and handpieces were used for each case depending on the location and consistency of the tumor.Results: All patients experienced an improvement in preoperative signs and symptoms, pain, proptosis, diplopia, or lagophthalmos. Visual acuity, which had been reduced due to the tumor, was also recovered. There were no intraoperative or postoperative complications due to the use of the device.Conclusions: The ultrasonic aspirator is a safe, useful device that can successfully remove or debulk infiltrating orbital masses through any orbital access, regardless of their consistency. It is helpful in cases of difficult anatomical access or difficult extraction due to size or adhesions to the surrounding tissues.

[Transcranial microsurgical decompression of the optic canal in surgical treatment of meningiomas of the sellar region]

RATIONALE

When removing the meningiomas of the sellar region, there is always a risk of visual impairment for various reasons, in particular, as a result of traction damage to the optic nerve. Decompression of the optic canal increases nerve mobility during tumor manipulation. In cases of meningioma growing into the canal, its decompression often seems necessary.

AIM

Evaluation of the effectiveness and risks of performing decompression of the optic canal.

MATERIALS AND METHODS

The study included patients with meningiomas of the parasellar location, who underwent surgical treatment at the Burdenko Neurosurgical Center for the period from 2001 to 2017. They were divided into two groups - main and control. The main group consisted of 129 patients who underwent decompression of the optic nerve canals when the tumor was removed. The tumor matrix in this group was most often located in the region of the tuberum sellae, supradiaphragmally, in the region of the anterior clinoid process and the optic canal. In 31 cases, decompression was bilateral - during one operation and using one access in 27 patients; in 4 cases, the decompression of the second canal was delayed for 1.5-3 months after the first operation. 160 decompressions were performed by the intradural and 7 - by extradural methods. During intradural decompression, the roof of the optic canal was resected, and during extradural decompression, the lateral wall of the canal was trephined. The control group consisted of 308 patients who did not undergo canal decompression when the tumor was removed. It included meningiomas with a predominant location of the matrix in the area of the tuberclum and diaphragm of the sella. Tumors in both groups were removed according to the same principles (matrix coagulation, mainly the gradual removal of the tumor, the use of ultrasonic aspirator, a situational decision on the radicality of the operation, etc.). The main difference between operations in these two groups was only canal related algorithms (with or without its trepanation), as well as the probable prevalence of significant lateral tumor growth in cases with canal trepanation. Visual functions in the «primary» group were evaluated before and after operations with trepanation of the canal depending on various factors - the initial state of vision and the radicality of the tumor excision, including removal from the canal. The differences in the postoperative dynamics of vision in the main and control groups were studied. The primary data processing was carried out using the program MSExcel. Secondary statistical processing was carried out using the program Statistica. To assess the statistical significance of differences in the results obtained in the compared patient groups, the Chi-square test was used, and in the case of small groups - the exact Fisher test was applied.

RESULTS

In the main group postoperative vision improvement of varying degrees on the side of trepanation was registered in 36.9% (59 out of 160) cases, no vision changes were found in 36.9% (59 out of 160), and in 26,2% (42 out of 160) the eyesight deteriorated. If preserving vision is attributed to a satisfactory result, then in general the results of these operations should be considered good. A comparative study of the results of removal of meningiomas with trepanation of the canals (main group) or without it (control group) was carried out among patients with the most critical vision situation (visual acuity 0.1 and below, up to only light perception). These groups are comparable in the number of observations - 62 and 73 respectively. The predominance of cases with improved vision in the main group compared with the control group (50.0% versus 38.36%) and a lower incidence of vision impairment (22.58% versus 34.25%) were found. However, the revealed differences are statistically unreliable and make it possible for us to talk only about the trend. The complications associated with trepanation of the canal include mechanical damage to the nerve by the drill. In our series of observations, there was only 1 case of abrasion of the nerve surface with the burr, which did not lead to a significant visual impairment. With the intradural method of trepanation in the area of the medial wall of the canal, the sphenoid sinus may open (in our series, in 34 cases out of 160 trepanations). Immediately closure of these defects was performed by various auto- and allomaterials in various combinations (pericranium, fascia, muscle fragment, hemostatic materials, and fibrin-thrombin glue). A true complication - CSF rhinorrhea liquorrhea developed in only one case, which required transnasal plastic surgery of the CSF fistula using a mucoperiostal flap.

CONCLUSIONS

1. Trepanation of the optic canal in cases of meningiomas of parasellar localization is a relatively safe procedure in the hands of a trained neurosurgeon and does not worsen the results of operations compared with the excision of the same tumors without trepanation of the canal. 2. The literature data and the results of our study make it possible to consider the decompression of the optic canal as an optional, but in many cases, useful option that facilitates the transcranial removal of some meningiomas of the sellar region.

Deep Lateral Wall Partial Rim-Sparing Orbital Decompression with Ultrasonic Bone Removal for Treatment of Thyroid-Related Orbitopathy

Purpose

To describe the results of thyroid-related orbitopathy (TRO) treated by ultrasonic deep lateral wall bony decompression with partial rim sparing (DLW-PRS).

Methods

A review was carried out, from January 2015 to September 2017, of all patients treated with ultrasonic DLW-PRS decompression using a SONOPET® (Stryker, Kalamazoo, MI, USA) ultrasonic aspirator, using a lateral, small triangle flap incision for access. The primary outcome was the change in proptosis (measured by the difference in Hertel exophthalmometry measurements). Other secondary outcomes were changes in visual acuity (VA) (using Snellen scale, decimal fraction), presence of lagophthalmos, eyelid retraction (measured by upper eyelid margin distance to the corneal reflex (MRD₁) and lower eyelid margin distance to the corneal reflex (MRD₂), and presence of exposure keratopathy).

Results

A total of 58 orbital decompressions in 35 patients were reviewed, with 23 patients (65.7%) having bilateral decompressions. There was a female preponderance with 26 patients (74.2%), and the mean age ± standard deviation was 52.6 ± 13.9 years. Mean proptosis was 24.51 ± 1.76 mm preoperatively, reduced to 19.61 ± 1.27 mm in final follow-up. The mean reduction was 4.9 ± 1.54 mm. VA improved from 0.8 ± 0.14 to 0.9 ± 0.12, p=0.039. 5 of 13 patients (38.4%) with preoperative diplopia reported improvement or complete resolution after surgery. MRD₁ was reduced from 5.25 ± 0.88 mm to 4.49 ± 0.7 mm. MRD₂ was also reduced from 6.3 ± 0.88 mm to 5.0 ± 0.17 mm. Presence of lagophthalmos was reduced from 35 eyes (60.3%) to five (8.6%); the presence of epiphora was also reduced from 20 patients (57.1%) to 3 (8.5%) following decompression. Complications of the surgery included zygomatic hypoaesthesia in 14 (40%) patients in the early postoperative period and chewing alterations in 10 (28.5%) of the patients. All of these complications were resolved at the 6-month follow-up visit. We noted no surgical complications such as ocular or soft tissue damage, infection, inflammation, or visual loss.

Conclusions

The SONOPET® ultrasonic bone curette can be used safely and effectively for DLW orbital decompression surgery. The main benefits were good visualization and handling of tissues and speed and ease of use of the equipment. This trial is registered with ClinicalTrials.gov identifier: NCT04025034.

Use of Ultrasonic Device in Cervical and Thoracic Laminectomy: a Retrospective Comparative Study and Technical Note

Multilevel severe compressive myelopathy is a challenging disorder for the surgeons, the aim of this study is to assess the efficacy and safety of a newly designed ultrasonic burr as an assistant tool to the ultrasonic scalpel in laminectomy for this disease. This is a retrospective comparative study, the included subjects were patients who received cervical and thoracic laminectomy using ultrasonic device (LUD, n = 9, 10 surgeries) and controls with the high-speed burr (LHB, n = 16). Fifteen patients (60.0%) showed severe cord occupancy and the average number of laminae operated was 3.5. Ultrasonic devices caused less blood loss (P = 0.02) and quicker operative time per level (P < 0.001) than LHB, and was associated with more operated laminae (P = 0.04). Preoperative JOA scores (P = 0.51), improvement rate (P = 0.47), and dural injury (P = 0.51) were not related to LUD. Our experience indicates ultrasonic devices are safe and effective for laminectomy treating multilevel and severe compressive myelopathy, the instrument could be used with ease especially for cases with ossified posterior longitudinal ligament and ossification of the ligamentum flavum, proper utility of the instrument is crucial to prevent complications.

Novel use of an ultrasonic bone aspirator for extended endoscopic frontal sinusotomy: A feasibility study

INTRODUCTION

Extended endoscopic frontal sinusotomy is often required for surgical management of anterior skull base pathology. Such approaches are necessary for access to pathology and maintenance of postoperative frontal sinus outflow tract drainage. Cold steel instrumentation and endoscopic high-speed microdrills are typically used for bony removal during extended frontal sinus approaches but are associated with certain drawbacks, such as thermal injury and obscuration of the surgical field with bone dust.

OBJECTIVE

We investigated the ultrasonic bone aspirator (UBA) as an adjunctive tool for extended endoscopic frontal sinusotomy in the setting of skull base surgery.

METHODS

Medical records of patients who underwent either Draf IIB or Draf III sinusotomies from 2011 to 2014 were reviewed. The patients were split into two cohorts based on instrumentation: those who received sinusotomy primarily with the UBA, and those who had sinusotomy performed with conventional instrumentation only. The patients were followed up after surgery with routine endoscopic examinations and imaging when indicated. Patient demographics, surgical approach, operative complications, and postoperative outcomes were evaluated.

RESULTS

A total of 18 patients underwent endoscopic extended frontal sinusotomy for a variety of skull base pathologies with the UBA and the conventional instrumentation cohorts, which contained nine patients each. Five of the nine patients in the UBA cohort received Draf III sinusotomies compared with three of nine in the conventional cohort. Three patients in the UBA cohort experienced postoperative transient pressure hyperemia of the lip; this was seen in a single patient in the conventional cohort. All patients with postoperative endoscopic examinations maintained frontal sinus ostial patency to varying degrees, irrespective of cohort. Lund-Mackay scores and the need for operative revision of the frontal sinus were similar for both groups and seemed to be related to the use of postoperative radiation.

CONCLUSION

The UBA was a safe, effective tool for extended endoscopic frontal sinusotomy in endoscopic skull base surgery.

Endoscopic endonasal optic nerve and orbital apex decompression for nontraumatic optic neuropathy: surgical nuances and review of the literature

OBJECT

While several approaches have been described for optic nerve decompression, the endoscopic endonasal route is gaining favor because it provides excellent exposure of the optic canal and the orbital apex in a minimally invasive manner. Very few studies have detailed the experience with nontraumatic optic nerve decompressions, whereas traumatic cases have been widely documented. Herein, the authors describe their preliminary experience with endoscopic endonasal decompression for nontraumatic optic neuropathies (NONs) to determine the procedure's efficacy and delineate its potential indications and limits.

METHODS

The medical reports of patients who had undergone endoscopic endonasal optic nerve and orbital apex decompression for NONs at the Lyon University Neurosurgical Hospital in the period from January 2012 to March 2014 were reviewed. For all cases, clinical and imaging data on the underlying pathology and the patient, including demographics, preoperative and 6-month postoperative ophthalmological assessment results, symptom duration, operative details with video debriefing, as well as the immediate and delayed postoperative course, were collected from the medical records.

RESULTS

Eleven patients underwent endoscopic endonasal decompression for NON in the multidisciplinary skull base surgery unit of the Lyon University Neurosurgical Hospital during the 27-month study period. The mean patient age was 53.4 years, and there was a clear female predominance (8 females and 3 males). Among the underlying pathologies were 4 sphenoorbital meningiomas (36%), 3 optic nerve meningiomas (27%), and 1 each of trigeminal neuroma (9%), orbital apex meningioma (9%), ossifying fibroma (9%), and inflammatory pseudotumor of the orbit (9%). Fifty-four percent of the patients had improved visual acuity at the 6-month follow-up. Only 1 patient whose sphenoorbital meningioma had been treated at the optic nerve atrophy stage continued to worsen despite surgical decompression. The 2 patients presenting with preoperative papilledema totally recovered. One case of postoperative epistaxis was successfully treated using balloon inflation, and 1 case of air swelling of the orbit spontaneously resolved.

CONCLUSIONS

Endoscopic endonasal optic nerve decompression is a safe, effective, and minimally invasive technique affording the restoration of visual function in patients with nontraumatic compressive processes of the orbital apex and optic nerve. The timing of decompression remains crucial, and patients should undergo such a procedure early in the disease course before optic atrophy.