The Reliability of the Ultrasonic Bone Scalpel in Cervical Spondylotic Myelopathy: A Comparative Study of 46 Patients

The Ultrasonic Bone Scalpel does not Outperform the High-Speed Drill: A Single Academic Experience

BACKGROUND

Spinal decompression and osteotomies are conventionally performed using high-speed drills (HSDs) and rongeurs. The ultrasonic bone scalpel (UBS) is a tissue-specific osteotome that preferentially cuts bone while sparing the surrounding soft tissues. There is ongoing investigation into its ability to optimize peri- and postoperative outcomes in spine surgery. The purpose of this study was to compare the intraoperative metrics and complications during a transition period from HSD to UBS.

METHODS

A single-institution, single-surgeon retrospective analysis was conducted of patients undergoing spine surgery from January 2020 to December 2021. Statistical analyses were performed to detect associations between the surgical technique and outcomes of interest. A P value < 0.05 was considered statistically significant.

RESULTS

A total of 193 patients met the inclusion criteria (HSD, n = 100; UBS, n = 93). Multivariate logistic regression revealed similar durotomy (P = 0.10), nerve injury (P = 0.20), and reoperation (P = 0.68) rates. Although the estimated blood loss (EBL) and length of stay were similar, the operative time was significantly longer with the UBS (192.81 vs. 204.72 minutes; P = 0.03). Each subsequent surgery using the UBS revealed a 3.1% decrease in the probability of nerve injury (P = 0.026) but had no significant effects on the operative time, EBL, or probability of durotomy or reoperation.

CONCLUSIONS

The UBS achieves outcomes on par with conventional tools, with a trend toward a lower incidence of neurologic injury. The expected reductions in EBL and durotomy were not realized in our cohort, perhaps because of a high proportion of revision surgeries, although these might be dependent on surgeon familiarity, among other operative factors. Future prospective studies are needed to validate our results and further refine the optimal application of this device in spine surgery.

Ultrasonic bone curette-assisted unilateral approach for bilateral decompression with MIS-TLIF for severe lumbar spinal stenosis

PURPOSE

We aimed to evaluate the clinical efficacy of bilateral decompression with minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) assisted by an ultrasonic bone curette (UBC) for treating severe degenerative lumbar spinal stenosis (DLSS) and traditional tool laminectomy decompression MIS-TLIF for treating severe DLSS.

METHODS

The clinical data of 128 patients with single-segment severe DLSS who were admitted between January 2017 and December 2021 were retrospectively analyzed. Among them, 67 patients were treated with unilateral fenestration and bilateral decompression MIS-TLIF using an ultrasonic bone curette (UBC group), whereas 61 patients were treated with unilateral fenestration and bilateral decompression MIS-TLIF using traditional tools (traditional group, control). A visual analog scale (VAS) was used to evaluate back and lower limb pain before the operation,immediate postoperative, and one week, 3, 6, 12, and 24 months after the operation. Oswestry disability index (ODI) and Zurich claudication score (ZCQ) were employed to evaluate the improvement in low back and lower limb function. At the last follow-up, the Bridwell bone graft fusion standard was utilized to evaluate bone graft fusion.

RESULTS

The decompression time of laminectomy was significantly shorter in the UBC group than in the traditional group (control group), and the intraoperative blood loss and postoperative drainage volume were significantly less in those in the control group (P < 0.05). The VAS, ODI, and ZCQ scores of the two groups after the operation were significantly improved compared to those before the operation (P < 0.05). The UBC group had better VAS back scores than the control group immediate postoperative and one week after the operation(P < 0.05). The UBC group had better VAS lower limb scores than the control group immediate postoperative (P < 0.05).The incidence of perioperative complications, hospitalization time, dural sac cross-sectional area (CSA), and dural sac CSA improvement rate did not differ significantly between the two groups (P > 0.05). VAS and ODI scores did not differ significantly between the two groups before,three, six months, one year, and two years after surgery (P > 0.05). The ZCQ scores did not differ significantly between the two groups before the operation at one week, six months, one year, and two years after the operation (P > 0.05). According to the Bridwell bone graft fusion standard, bone graft fusion did not occur significantly between the two groups (P > 0.05) at the last follow-up.

CONCLUSIONS

UBC unilateral fenestration bilateral decompression MIS-TLIF in treating severe DLSS can achieve clinical efficacy as traditional tool unilateral fenestration bilateral decompression MIS-TLIF and reduce intraoperative blood loss and postoperative drainage. It can also shorten the operation time, effectively reduce the work intensity of the operator, and reduce the degree of low back pain during short-term follow-ups. Therefore, this is a safe and effective surgical method.

Optimizing milling parameters based on full factorial experiment and backpropagation artificial neural network of lamina milling temperature prediction model

BACKGROUND

Milling operations of laminae in spinal surgery generate high temperatures, which can lead to thermal injury and osteonecrosis and affect the biomechanical effects of implants, ultimately leading to surgical failure.

OBJECTIVE

In this paper, a backpropagation artificial neural network (Bp-ANN) temperature prediction model was developed based on full factorial experimental data of laminae milling to optimize the milling motion parameters and to improve the safety of robot-assisted spine surgery.

METHODS

A full factorial experiment design were used to analyze the parameters affecting the milling temperature of laminae. The experimental matrixes were established by collecting the corresponding cutter temperature Tc and bone surface temperature Tb for the milling depth, feed speed and different bone densities. The Bp-ANN lamina milling temperature prediction model was constructed from experiment data.

RESULTS

Increasing milling depth increases bone surface and cutter temperature. Increasing feed speed had little effect on cutter temperature, but decreased bone surface temperature. Increasing bone density of laminae increased cutter temperature. The Bp-ANN temperature prediction model had best training results in the 10th epoch, and there is no overfitting (training set R= 0.99661, validation set R= 0.85003, testing set R= 0.90421, all temperature data set R= 0.93807). The goodness of fit R of Bp-ANN was close to 1, indicating that the predicted temperature was in good agreement with the experiment measurements.

CONCLUSION

This study can help spinal surgery-assisted robot to select appropriate motion parameters at different density bones to improve lamina milling safety.

Ultrasonic Bone Scalpel versus Conventional Methods for Osteotomy in Posterior Surgery for Cervical Spondylotic Myelopathy: A Review and Meta-Analysis

Posterior methods for cervical myelopathy include laminoplasty and laminectomy with/without fusion. A more recent innovation in these treatments is the use of an ultrasonic bone shaver for osteotomy. In this study, we examined the perioperative results after laminectomy/laminoplasty between conventional methods (rongeur/high-speed drill) vs. piezosurgery-based instruments. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed and the search was performed on four databases (PubMed, Scopus, EMBASE, and Google Scholar). Seven comparative studies were chosen after thorough screening by the authors and a meta-analysis was performed between piezosurgery and conventional technique to ascertain intraoperative and postoperative results after laminectomy/laminoplasty. The analysis includes four retrospective cohort studies and three randomized controlled trials published between 2015 and 2022. The mean age ranged from 55.5 to 64.2 years. Blood loss was significantly reduced in the piezosurgery group, other findings were not significant. On subgroup analysis, laminoplasty dramatically reduced blood loss and the rate of iatrogenic dural rips in the piezosurgery group. The use of ultrasonic bone shaver for osteotomy in cervical spondylotic myelopathy is related to significantly decreased blood loss and no significant increase in postoperative drainage, operative time, complication rate, and functional outcomes as compared to traditional techniques. We noticed significantly reduced blood and rate of dural tears in the laminoplasty subgroup with the use of ultrasonic bone shaver, which was not mirrored in the laminectomy subgroup. Careful intraoperative handling of the instrument can help prevent iatrogenic dural tears and nerve damage.

Ultrasonic bone scalpel in spine surgery

Background

Spine surgery has always been considered technically demanding even in the hands of the most experienced surgeon on account of close proximity of vital soft tissue structures. Technical advancements over the last few decades have been crucial for the progress of this complex speciality which not only increased the surgical accuracy, but patient safety as well. Ultrasonic devices are one such innovation based on piezoelectric vibrations, patented by Fernando Bianchetti, Domenico Vercellotti, and Tomaso Vercellotti in 1988.

Methods

We did an extensive literature search on ultrasonic devices and their applications in the field of spine surgery.

Results

We present the various ultrasonic bone devices available including their physical, technologic and clinical aspects in spine surgery. We also attempt to cover the limitations and future advances of Ultrasonic bone scalpel (UBS) in particular, which would be interesting and informative for any spine surgeon who is novice in this field.

Conclusion

UBS has been found to be safe and effective in all forms of spine surgeries offering distinct advantages over conventional instruments, although limited by an inherent learning curve.

Effect of Ultrasonic Osteotome on Therapeutic Efficacy and Safety of Spinal Surgery: A System Review and Meta-Analysis

Background. A meta-analysis was performed to evaluate the effectiveness and safety of ultrasonic osteotomes in spine surgery to standard spinal surgery procedures. Methods. Using the search keywords “bone curette”, “cutter”, “scalpel”, “bone shaver”, “aspirator”, “osteotome”, “ultrasonic”, “piezosurgery”, and “ ${\text{dent}\hspace{0.17em}\hspace{0.17em}}^{\ast }$ ” in the databases of PubMed (1966-2021.12), Cochrane Library, Embase (1986-2018.12), Web of Science (1978-2021.12), and China Academic Journals Full-Text Database (CNKI, 1979-2021.12). Two researchers reviewed the literature, extracted and extensively assessed the data, and included information on the study quality. RevMan v5.3.5.0 was used for the meta-analysis. Results. A total of 10 trials with a total of 911 patients were included. The meta-analysis findings revealed that, when compared to traditional methods, ultrasonic osteotomes could save operation time ( $\text{OR}=-18.83$ , 95 percent CI (-22.76, -14.99), $P=0.03$ ) and reduce intraoperative bleeding ( $\text{OR}=-66.73$ , 95 percent CI (-75.70, -57.76), $P=0.04$ ) and postoperative complications ( $\text{OR}=0.38$ , 95 percent CI (0.21, 0.69), $P=0.001$ ). There was, however, no significant difference in the hospital stay ( $\text{OR}=-1.34$ , 95 percent CI (-1.90, -0.77), $P=0.23$ ) and symptom improvement rate ( $\text{OR}=1.03$ , 95 percent CI (0.73, 1.45), $P=0.86$ ). Conclusion. There is evidence that using an ultrasonic osteotome in spine surgery is safe and effective and may minimize intraoperative bleeding and save time. However, there is no significant difference in symptom improvement rate, hospital stay length, or postoperative complications compared to standard surgical equipment. Therefore, more high-quality investigations are needed to corroborate the initial results.

Safety and Effectiveness of Modified Expansive Open-door Laminoplasty Using a Ultrasonic Bone Scalpel Compared With a High-speed Drill

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

Our study aimed to compare the effectiveness and safety of ultrasonic bone scalpel (UBS) and high-speed drill (HSD) in modified expansive open-door laminoplasty.

SUMMARY OF BACKGROUND DATA

The traditional methods of decompression mostly use HSD and laminectomy forceps to lift the lamina. As a new type of bone cutting instrument, UBS has the advantages of good tissue selectivity, bone cutting accuracy, good hemostasis, cold cutting, and easy operation, leading to its popular use in surgery.

MATERIALS AND METHODS

Forty-two patients who underwent modified expansive open-door laminoplasty for multilevel cervical spondylotic myelopathy were included in this study. They were divided into HSD and UBS groups (n=18 and 24, respectively). Data on demographics, operation duration, blood loss, postoperative drainage, extubation time, length of stay, cost of hospitalization, and complications were collected and compared. Modified Japanese Orthopedic Association score, visual analog scale, Neck Disability Index, and axial symptoms were also recorded and analyzed.

RESULTS

The blood loss in the UBS group was 255.4±217.5 mL, which was lower than that in the HSD group (490.6±389.4 mL, P=0.030). The cost of hospitalization was similar between the 2 groups. The operative time and postoperative drainage did not significantly differ (P>0.05). The modified Japanese Orthopedic Association score, visual analog scale score, and Neck Disability Index score after surgery were better than those before surgery (P<0.05), but no significant difference existed between the 2 groups in each period (P>0.05). No significant difference existed in the incidence of axial symptoms and other complications (P>0.05).

CONCLUSION

The application of the UBS to modified open-door laminoplasty resulted in a safe and effective decompression effect and reduced blood loss without increasing cost benefit.

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.

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.

Bone-to-bone ligament preserving laminoplasty technique for reconstruction of laminae

Introduction

Laminoplasty is a method used in spinal intradural tumor surgery to reduce the possibility of iatrogenic deformity. In classic laminoplasty, the interspinous, supraspinous, and ligamentum flavum integrity may be impaired, thereby creating a risk of deformity despite the laminoplasty. The aim of this study was to review the outcomes of bone-to-bone ligament preserving laminoplasty (BLP laminoplasty) technique.

Materials and Methods

The data of 14 cases who underwent BLP laminoplasty for intradural spinal tumor between 2017 and 2019 were reviewed. Through examination of preoperative and postoperative computed tomography images and flexion-extension lateral X-rays, the fusion and kyphotic changes were evaluated in the laminas. An axial Visual Analog Scale (VAS) was used to evaluate clinical satisfaction.

Results

The cases comprised 10 females and 4 males, with a mean age of 39.2 years (range, 16-52 years). The masses were intramedullary in six cases and extramedullary in eight. Lumbar region localization was most frequent. Ependymoma was determined in 8 cases, schwannoma in 4, and meningioma in 2. Laminoplasty was applied at 43 levels (10 thoracic and 33 lumbar). No complications were observed, and fusion was obtained in all the cases at the end of 1 year. No segmental kyphotic changes were determined. In the clinical evaluation, the VAS scores improved from 3.4 ± 2.0 preoperatively to 1.8 ± 2.1 postoperatively.

Conclusion

BLP laminoplasty is a safe technique which preserves posterior ligamentous integrity. Furthermore, the use of ultrasonic bone scalpel provides a narrower gap between laminae and other bones, preventing dislocation, and allowing for more fusion, and consequently preventing kyphosis.

The Effectiveness and Safety of Ultrasonic Bone Scalpel Versus Conventional Method in Cervical Laminectomy: A Retrospective Study of 311 Patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The aim of this study was to compare the results of cervical laminectomy (CL) performed with ultrasonic bone scalpel (UBS) or conventional method (CM).

METHOD

This study comprised 311 CL performed by a single surgeon between January 2004 and December 2017. Group A (GpA) comprised 124 cases of CL performed using UBS, while Group B (GpB) comprised 187 cases of CL performed using CM. These 2 groups were compared in terms of demographic characteristics of patients, duration of surgery, estimated blood loss, and surgical complications.

RESULTS

GpA included 112 males and 12 females, mean age being 61.18 years. GpB comprised 166 males and 21 females, mean age being 62.04 years. Mean duration of surgery, estimated blood loss, and length of hospital stay was 65.52/70.87 minutes, 90.24/98.40 mL, and 4.80/4.87 days in GpA and GpB, respectively. Six patients were reported to have dural injuries in each group. In GpA, 2 cases of C5 palsy and 1 nerve root injury was observed, while in GpB, 3 cases of C5 palsy and no nerve root injury was reported. One patient had developed transient neurological deterioration postsurgery in GpA as against 11 patients in GpB.

CONCLUSION

Neurological complications observed in CM leads to intensive care unit admission, additional morbidity, and additional expenditure, whereas UBS provides a safe, rapid, and effective means of performing CL, thereby decreasing the rate of surgical complications and postoperative morbidity.

How I do it: en-bloc subaxial cervical laminectomy using a high-speed drill with a footplate attachment

BACKGROUND

Cervical laminectomy is a common strategy to decompress the spinal canal.

METHODS

The anatomy of the cervical spine and surrounding critical structures as viewed from the posterior approach is described. The use of a high-speed drill with a footplate attachment to make laminar troughs with an en-bloc subaxial cervical laminectomy is described with a discussion on surgical technique and complication avoidance.

CONCLUSION

This technique allows for a safe, comfortable, and rapid decompression of the cervical spine with minimal risk. For routine cases, this may potentially be more safe and cost-effective than using a cutting bur or bone scalpel attachment.

Effects of Combined Use of Ultrasonic Bone Scalpel and Hemostatic Matrix on Perioperative Blood Loss and Surgical Duration in Degenerative Thoracolumbar Spine Surgery

How to decrease intraoperative bleeding, shorten surgical time, and increase safety in spinal surgery is an important issue. Ultrasonic bone removers and FloSeal have been proven to increase safety, reduce the surgical duration, and decrease intraoperative bleeding in skull base surgery. Therefore, we aimed to compare the surgical duration, blood loss, and complications during spinal surgery with or without the use of FloSeal and an ultrasonic bone scalpel. Therefore, we retrospectively reviewed 293 patients who underwent thoracolumbar spinal surgery with decompression and instrumented fusion performed by a single surgeon. We divided these patients into three groups, including nonuse of FloSeal nor a bone scalpel (group A), use of FloSeal only (group B), and use of FloSeal and a bone scalpel (group C) intraoperatively after pairing in terms of age, sex, and surgical level. The surgical duration, blood loss, and occurrence of complications were all recorded. The mean surgical duration in group A was 160 mins, in group B it was 167 mins, and in group C it was 134 mins. The mean blood loss was 700 ml in group A, 682 ml in group B, and 383 ml in group C. Six patients sustained intraoperative dura injuries in total, 3 in group A, 2 in group B, and 1 in group C. No postoperative neurologic defects or occurrences of hematoma were recorded. According to our results, we concluded that combined use of FloSeal and bone scalpels is recommended during primary thoracolumbar spinal surgery to reduce the intraoperative blood loss and shorten the surgical duration.

[Application of ultrasonic osteotome in the posterior lumbar interbody fusion surgery by unilateral fenestration and bilateral decompression in the treatment of degenerative lumbar spinal stenosis]

OBJECTIVE

To compare the effectiveness of posterior lumbar interbody fusion (PLIF) by unilateral fenestration and bilateral decompression with ultrasounic osteotome and traditional tool total laminectomy decompression PLIF in the treatment of degenerative lumbar spinal stenosis.

METHODS

The clinical data of 48 patients with single-stage degenerative lumbar spinal stenosis between January 2017 and June 2017 were retrospectively analyzed. Among them, 27 patients were treated with unilateral fenestration and bilateral decompression PLIF with ultrasonic osteotome (group A), and 21 patients were treated with total laminectomy and decompression PLIF with traditional tools (group B). There was no significant difference in gender, age, stenosis segment, degree of spinal canal stenosis, and disease duration between the two groups ( P>0.05), which was comparable. The time of laminectomy decompression, intraoperative blood loss, postoperative drainage volume, and the occurrence of operation-related complications were recorded and compared between the two groups. Bridwell bone graft fusion standard was applied to evaluate bone graft fusion at last follow-up. Visual analogue scale (VAS) score was used to evaluate the patients' lumbar and back pain at 3 days, 3 months, and 6 months after operation. Oswestry disability index (ODI) score was used to evaluate the patients' lumbar and back function improvement before operation and at 6 months after operation.

RESULTS

The time of laminectomy decompression in group A was significantly longer than that in group B, and the intraoperative blood loss and postoperative drainage volume were significantly less than those in group B ( P<0.05). There was no nerve root injury, dural tear, cerebrospinal fluid leakage, and hematoma formation during and after operation in the two groups. All patients were followed up after operation, the follow-up time in group A was 6-18 months (mean, 10.5 months) and in group B was 6-20 months (mean, 9.3 months). There was no complication such as internal fixation fracture, loosening and nail pulling occurred during the follow-up period of the two groups. There was no significant difference in VAS scores between the two groups at 3 days after operation ( t=1.448, P=0.154); the VAS score of group A was significantly lower than that of group B at 3 and 6 months after operation ( P<0.05). The ODI scores of the two groups were significantly improved at 6 months after operation ( P<0.05), and there was no significant difference in ODI scores between the two groups before operation and at 6 months after operation ( P>0.05). At last follow-up, according to Bridwell criteria, there was no significant difference in bone graft fusion between the two groups ( Z=-0.065, P=0.949); the fusion rates of groups A and B were 96.3% (26/27) and 95.2% (20/21) respectively, with no significant difference ( χ 2=0.001, P=0.979 ).

CONCLUSION

The treatment of lumbar spinal stenosis with unilateral fenestration and bilateral decompression PLIF with ultrasonic osteotome can achieve similar effectiveness as traditional tool total laminectomy and decompression PLIF, reduce intraoperative blood loss and postoperative drainage, and reduce lumbar back pain during short-term follow-up. It is a safe and effective operation method.

Ultrasonic bone scalpel: utility in cervical corpectomy. A technical note

PURPOSE

Anterior cervical corpectomy and fusion (ACCF) is a technically challenging surgery. Use of conventional instruments like high-speed burr and kerrison rongeurs is associated with high complication rates such as increased blood loss and incidental durotomy. Use of ultrasonic bone scalpel (UBS) in cervical corpectomy helps to minimize such adverse events.

METHODS

We performed a retrospective study based on the data of 101 consecutive patients who underwent cervical corpectomies with UBS for different cervical spine pathologies from December 2014 to December 2016. Total duration of surgery, time taken for corpectomy, estimated blood loss, and incidental durotomies were noted.

RESULTS

Total surgical time was 30-80 min (59.36 ± 13.21 min) for single-level ACCF and 60-120 min (92.74 ± 21.04 min) for double-level ACCF. Time taken for single-level corpectomy was 2 min 11  ± 10 s and 3 min 41  ± 20 s for double-level corpectomy. Estimated blood loss ranged from 20-150 ml (52.07 ± 29.86 ml) in single level and 40-200 ml (73.22 ± 41.64 ml) in double level. Four (3.96%) inadvertent dural tears were noted, two during single-level corpectomy and other two during double-level corpectomy.

CONCLUSIONS

Use of UBS is likely to provide a safe, rapid, and effective surgery when compared to conventional rongeurs and high-speed burr. The advantages such as lower blood loss and lower intra-operative incidental dural tears were noted with the use of UBS.

Use of image-guided bone scalpel for resection of spine tumors: technical note

In the literature, the use of navigation for spine tumor surgery has largely centered on implant placement. We describe the cases of two patients with spinal tumors on whom we utilized our resection technique of registering an ultrasonic bone scalpel (UBS) to a navigation system. In both cases, we achieved a satisfactory tumor resection with negative margins and excellent neurologic outcomes. We feel that using the navigation-registered UBS is a valuable tool to increase the operator's ability to achieve desired resections while minimizing the neurologic deficits and operative morbidity associated with these challenging surgical cases.

[Safety and effectiveness of ultrasonic osteotome in posterior cervical laminectomy decompression and fusion]

Objective

To explore the safety of ultrasonic osteotome used in posterior cervical laminectomy decompression surgery and its effect on surgical outcome.

Methods

A clinical data of 52 patients with ossification of posterior longitudinal ligament of cervical spine (C-OPLL) undergoing posterior cervical laminectomy decompression and fusion (PCLDF) between April 2013 and April 2017 was retrospectively analysed. The patients were divided into two groups according to whether using the ultrasonic osteotome during operation: group A (20 cases, ultrasonic osteotome group) and group B (32 cases, traditional gun-clamp decompression group). There was no significant difference in gender, age, body weight, height, preoperative hemoglobin, and Japanese Orthopedic Association (JOA) score between the two groups ( P>0.05). The operation time, intraoperative blood loss, postoperative drainage volume, hospitalization time, complications, hemoglobin at 1 day after operation, and JOA score at 6 months after operation were recorded and compared between the two groups, and the improvement rate of JOA was calculated.

Results

The operation time and intraoperative blood loss in group A were significantly less than those in group B ( P<0.05); there was no significant difference in the drainage volume and hospitalization time between the two groups ( P>0.05). The hemoglobin of group B was slightly higher than that of group A at 1 day after operation, but there was no significant difference between the two groups ( t=-1.260, P=0.214). All the patients were followed up 6-10 months (mean, 7.6 months). No serious complications such as C ₅ nerve paralysis, dural tear, infection, epidural hematoma, deep venous thrombosis, pulmonary embolism, transfusion allergy, or shock occurred during and after operation. The JOA scores of the two groups were significant improved at 6 months after operation when compared with preoperative scores ( P<0.05), and there was no significant difference in JOA score and improvement rate between the two groups at 6 months after operation ( P>0.05).

Conclusion

Compared with the traditional gun-clamp decompression, the effectiveness of PCLDF in treatment of C-OPLL by using ultrasonic osteotome is comparable, but the latter can effectively reduce the operation time and blood loss.

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

Background

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.

Methods

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.

Results

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.

Conclusions

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.

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.

Use of a Pediatric Craniotome Drill for Cervical and Thoracic Spine Decompression: Safety and Efficacy

BACKGROUND

Laminectomy, using a high-speed drill with an unprotected cutting drill bit, can be rapid and effective, but it has been associated with known complications. Another technique uses a pediatric craniotome drill with the footplate attachment. At present, there are no studies comparing clinical outcomes between these 2 stated decompressive techniques.

METHODS

A retrospective review was conducted at a single institution. Two cohorts of patients were considered based on the technical method of laminectomy for decompression. One group had decompression with utilization of a high-speed drill, whereas the other group had decompression with a pediatric craniotome drill with a footplate attachment. The outcomes from each group were compared based on the length of operation, estimated blood loss, and associated complications.

RESULTS

A total of 91 patients were included in the final analysis. Forty-five of the patients underwent laminectomy using a footplate and 46, using a high-speed drill. The footplate group was associated with significantly shorter operative time (159 vs. 205 minutes; P = 0.008). In addition, the footplate technique demonstrated less estimated blood loss (254 vs. 349 mL), and less incidence of durotomies (2.2% vs. 10.9%); however, neither of these 2 outcomes achieved statistical significance.

CONCLUSIONS

Despite being an older technique, there was a shorter operative time in the footplate group without increased blood loss or incidence of durotomy. Although comparable results are operator dependent, this technique is a safe alternative for performing cervical and thoracic laminectomies.

Technique for Mini-open Decompression of Chiari Type I Malformation in Adults

BACKGROUND: The technique for decompression of Chiari type I malformation relies on open exposure of craniocervical junction for suboccipital craniectomy and upper cervical laminectomy with or without duraplasty. There is no detailed technical report of a minimally invasive approach for Chiari decompression in adults.

OBJECTIVE: To describe a mini-open technique for decompression of Chiari type I malformation (including duraplasty) in adults.

METHODS: Six consecutive adult patients with symptomatic Chiari type I malformation underwent decompression through a 3 to 4 cm midline incision via a speculum retractor. All patients underwent a limited suboccipital craniectomy and C1 laminectomy with an ultrasonic bone scalpel. All patients underwent duraplasty with a synthetic dural substitute. In the 2 patients with syringomyelia, the arachnoid was opened and intradural dissection was carried out. In the remaining 4 patients, the arachnoid was left intact.

RESULTS: All operations were completed successfully through the mini-open exposure. Mean surgery time, blood loss, and length of stay were 114 min, 55 mL, and 1.3 days, respectively. Mean follow-up was 13.2 months (range 9-18). All patients had excellent clinical outcomes as defined by scores of 15 (3 patients) or 16 (3 patients) on Chicago Chiari Outcome Scale. There were no neurological complications or cerebrospinal fluid leaks. Postop computed tomography revealed good boney decompression. In the 2 patients with syringomyelia, MRI at 6 months revealed resolution of the syrinx.

CONCLUSION: Decompression of Chiari type I malformation in adults can be performed safely and effectively through the mini-open exposure described in this report.

Alternative technique in atypical spinal decompression: the use of the ultrasonic scalpel in paediatric achondroplasia

Spinal stenosis can be a very disabling condition. Surgical decompression carries a risk of dural tear and neural injury, which is increased in patients with severe stenosis or an atypical anatomy. We present an unusual case of symptomatic stenosis secondary to achondroplasia presenting in a paediatric patient, and highlight a new surgical technique used to minimise the risk of dural and neural injury during decompression.

Technical Aspects on the Use of Ultrasonic Bone Shaver in Spine Surgery: Experience in 307 Patients

Aim. We discuss technical points, the safety, and efficacy of ultrasonic bone shaver in various spinal surgeries within our own series. Methods. Between June 2010 and January 2014, 307 patients with various spinal diseases were operated on with the use of an ultrasonic bone curette with microhook shaver (UBShaver). Patients' data were recorded and analyzed retrospectively. The technique for the use of the device is described for each spine surgery procedure. Results. Among the 307 patients, 33 (10.7%) cases had cervical disorder, 17 (5.5%) thoracic disorder, 3 (0.9%) foramen magnum disorder, and 254 (82.7%) lumbar disorders. Various surgical techniques were performed either assisted or alone by UBShaver. The duration of the operations and the need for blood replacement were relatively low. The one-year follow-up with Neck Disability Index (NDI) and Oswestry Disability Index (ODI) scores were improved. We had 5 cases of dural tears (1.6%) in patients with lumbar spinal disease. No neurological deficit was found in any patients. Conclusion. We recommend this device as an assistant tool in various spine surgeries and as a primary tool in foraminotomies. It is a safe device in spine surgery with very low complication rate.