Potential risk of thermal damage to cervical nerve roots by a high-speed drill

Evaluation of a novel high speed burr tip for safe and efficient bone surgery in a sheep model

The exposure of neural structures by removing the overlying bone using a high-speed drill can cause iatrogenic injury to the dura, neural tissue, and vessels. We investigated the safety and efficacy of a novel Surgify Safety Burr (SSB), attachable to existing high-speed drills. Three anesthetized living sheep underwent cranial burr hole drilling (n = 19) and hemilaminectomies (n = 14) with the SSB and standard burrs. Drilling time, dural injury, and subjective evaluation of heating and haptic feedback of each burr were assessed. Cranial burr hole drilling was done using diamond (n = 3), fluted (n = 6), and SSB (n = 10) burrs. Penetrating dura damage was observed in 33% of the diamond burr drilled holes, and in 33% of the fluted burr drilled holes, but not in the holes drilled with the SSB. Hemilaminectomies were performed with the SSB (n = 7) and diamond (n = 7) burrs without drilling-induced dura damage. Mean drilling time was not significantly different in cranial drilling (SSB, 121 ± 18s; fluted burr, 63 ± 22s; diamond burr, 165 ± 29s) nor in hemilaminectomy (SSB, 108 ± 13s; diamond burr, 95 ± 18s). Subjective evaluation of the SSB suggested efficient bone removal without heating or chattering. The SSB is a safe and effective surgical tool in cranial drilling and hemilaminectomy procedures. Safety, efficacy, and clinical benefits should be established in human studies.

Efficiency and Heat Production of Ultrasonic Osteotome Strategy in Robot-Assisted Laminectomy

Study DesignA biomechanical study.ObjectiveWe aimed to assess temperature fluctuations when applying the ultrasonic osteotome during laminectomy and identify the most appropriate cutting method for robot-assisted laminectomy to mitigate the risk of heat-related injuries.MethodsUtilizing a robotic system for laminectomy, the study implemented the ultrasonic bone scalpel to cut both artificial polyurethane bones and animal spinal bones. The research focused on comparing and analyzing the maximum temperature of the inner surface of four types of artificial bones through three different cutting techniques: vertical constant cutting at speeds of .5 mm/s and 1 mm/s, as well as robot-assisted vertical reciprocating cutting. After the initial results, two optimal vertical cutting approaches were selected for subsequent trials, evaluating the effectiveness and temperature impact of various ultrasonic osteotome modes on 10 isolated spinal bones from pigs.ResultsWhen cutting polyurethane bones, reciprocating cutting demonstrated the lowest maximum temperature in contrast to constant speed cutting at .5 mm/s and 1 mm/s. In the animal bone trial, direct cutting registered an average maximum temperature of 43.25°C with an average cutting duration of 688.3 s, while reciprocating cutting recorded an average maximum temperature of 34.20°C with an average cutting time of 713.0 s.ConclusionsThe reciprocating cutting strategy utilized in robot-assisted ultrasonic osteotome is effective in reducing heat generation and maintaining high cutting efficiency.

Identifying Factors for Predicting Postoperative Segmental Motor Paralysis in Patients Undergoing Anterior Cervical Spine Surgery: A Multicenter Study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To investigate the incidence of and risk factors for segmental motor paralysis after anterior cervical spine surgery.

SUMMARY OF BACKGROUND DATA

Segmental motor paralysis is a potential complication following both anterior and posterior cervical decompression procedures; however, previous studies investigating risk factors for segmental motor paralysis after anterior cervical spine surgery were limited by small sample sizes. Consequently, the exact pathogenesis and risk factors for this complication remain poorly understood, highlighting the need for larger-scale investigations focused exclusively on anterior cervical spine surgeries.

MATERIALS AND METHODS

We retrospectively reviewed the clinico-demographic and operative factors and postoperative outcomes of 1428 patients undergoing anterior cervical spine surgery at three spine centers in Japan. Postoperative segmental motor paralysis was defined as deterioration of upper extremity muscle strength by ≥1 grade; recovery was defined as a return to preoperative muscle strength levels. Univariate and multivariate analyses were performed to identify risk factors.

RESULTS

Ninety-nine patients (6.9%) developed segmental motor paralysis, mostly involving the C5 segment (81.8%), the incidence being highest in patients with ossification of the posterior longitudinal ligament (OPLL) and those undergoing anterior cervical corpectomy and fusion or hybrid fusion (discectomy + corpectomy). Older age, male sex, higher body mass index, OPLL, and cervical corpectomy were independent risk factors for paralysis, with these patients having significantly worse clinical outcomes at 1 year postoperatively. Most patients (74/99, 79.6%) regained preoperative muscle strength levels at a final follow-up.

CONCLUSION

This study identified important clinico-demographic and operative risk factors for segmental motor paralysis after anterior cervical spine surgery. Patients undergoing corpectomy, with or without OPLL, were found to be at particularly high risk. While most patients recover well, worse outcomes with segmental motor paralysis highlight the importance of preventing this complication, particularly for OPLL patients and corpectomy procedures.

LEVEL OF EVIDENCE

Level III.

Application of continuous intraoperative neuromonitoring in the study of spinal nerve root thermal injury in a porcine model

BACKGROUND

A warning system to avoid potential nerve root thermal injury caused by automatic spine robot is essential. However, there is a lack of basic research to support the development of such warning system. The aims of this study are to confirm the feasibility of continuous intraoperative neuromonitoring (CIONM) in spinal nerve root monitoring and study the exposure time of spinal nerve root thermal injury at different temperature in a porcine model.

METHODS

The experiment was carried out on 32 nerve roots of 4 pigs (bilateral L4-S1 nerve roots). Sham group (CIONM only), control group (Room temperature stimulation with CIONM), and 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C temperature stimulation groups were conducted at random in each pig. The change of EMG was recorded continuously. The exposure time of nerve root injury at different temperatures was recorded. Histological analysis of the nerve roots was performed to confirm the injury.

RESULTS

The EMG of the sham, control, 40 °C and 45 °C groups were stable during the experiment, and no significant nerve root injury was observed on histological analysis. The time of 50% EMG amplitude decrease in 50℃, 55℃, 60℃ and 65℃ groups were 277.5 ± 18.2, 59.5 ± 6.2, 20.8 ± 1.0 and 16.5 ± 1.3 s, respectively. And the nerve specimens of these groups showed varying degrees of damage.

CONCLUSIONS

CIONM can be used for continuous monitoring of spinal nerve roots. For 5 min, 40℃ and 45℃ did not cause significant nerve root injury. However, when the temperature reached 50℃ and above, nerve roots appeared injury.

Superior orbital fissure syndrome after deep lateral orbital wall decompression in Graves' ophthalmopathy

PURPOSE

The superior orbital fissure contains cranial nerves III, IV, VI, and V1 with their three branches: frontal, lacrimal, and nasociliary. Superior orbital fissure syndrome (SOFS) is rare and can occur as a result of compression of these nerves due to trauma, bleeding, or inflammation in the retrobulbar space, but no cases of SOFS after deep lateral orbital wall decompression (DLOWD) have been reported. The aim of this paper is to describe this pathology, its possible causes, management, and outcome.

METHODS

Retrospective study of 575 DLOWD in patients with disfiguring exophthalmos due to Graves' ophthalmopathy performed in our hospital between 2010 and 2023. Three cases of postoperative SOFS were identified based on clinical presentation, history, physical examination, and radiological study. All patients were observed for a minimum of 12 months.

RESULTS

SOFS was diagnosed with the presence of ophthalmoplegia, ptosis, fixed and dilated pupils, hypo/anesthesia of the upper eyelid and forehead, loss of corneal reflex, and no loss of vision after DLOWD. Fractures, edema, and hemorrhages were excluded. They were treated with high-dose intravenous steroids and the patients recovered completely.

CONCLUSIONS

DLOWD challenges orbital surgeons because it requires removing bones near the globe or neurovascular structures. SOFS may occur due to the proximity and increased pressure on these structures.

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.

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.

Surgical Strategy and Application of Robotic-Assisted Benign Sacral Neurogenic Tumor Resection

BACKGROUND

Robotic surgery may be advantageous in neurogenic sacral tumor resection but only a few studies reported robotic-assisted neurogenic sacral tumor resection.

OBJECTIVE

To propose a new surgical strategy for robotic-assisted benign sacral neurogenic tumor resection and introduce the ultrasonic osteotomy surgical system in robotic surgery.

METHODS

Twelve patients who had robotic-assisted primary benign sacral neurogenic tumor resection between May 2015 and March 2021 were included. Our surgical strategy divides tumors into 4 types. Type I: Presacral tumors with diameter <10 cm. Type II: Narrow-base tumors involving the sacrum with diameter <10 cm. Type III: Broad-base tumors involving the sacrum with diameter <10 cm. Type IV: Tumors involving sacral nerve roots ≥2 levels and/or with diameter ≥10 cm.

RESULTS

Five type I, 5 type II, and 1 type III patients underwent tumor resection via an anterior approach, and 1 type IV patient via a combined approach. The median operation time, blood loss, and postoperative hospital stay of type I and II were much less than those of type IV. The ultrasonic osteotomy surgical system facilitated osteotomy in 2 type II and 1 type III patients. Eleven patients had total resections, and 1 type III patient had a partial resection. During the follow-up period of 7.9 to 70.9 months (median: 28.5 months), no local recurrences or deaths were noted.

CONCLUSION

With the largest single-center series to our knowledge, this surgical strategy helped to guide robotic-assisted benign sacral neurogenic tumor resection. The ultrasonic osteotomy surgical system was effective for type II and III.

Iatrogenic Nerve Injuries of the Upper Extremity: A Critical Analysis Review

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Iatrogenic nerve injuries may occur after any intervention of the upper extremity.

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Causes of iatrogenic nerve lesions include direct sharp or thermal injury, retraction, compression from implants or compartment syndrome, injection, patient positioning, radiation, and cast/splint application, among others.

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Optimal treatment of iatrogenic peripheral nerve lesions relies on early and accurate diagnosis.

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Advanced imaging modalities (e.g., ultrasound and magnetic resonance imaging) and electrodiagnostic studies aid and assist in preoperative planning.

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Optimal treatment of iatrogenic injuries is situation-dependent and depends on the feasibility of direct repair, grafting, and functional transfers.

A Risk Calculator for the Prediction of C5 Nerve Root Palsy After Instrumented Cervical Fusion

BACKGROUND

C5 palsy is a common postoperative complication after cervical fusion and is associated with increased health care costs and diminished quality of life. Accurate prediction of C5 palsy may allow for appropriate preoperative counseling and risk stratification. We primarily aim to develop an algorithm for the prediction of C5 palsy after instrumented cervical fusion and identify novel features for risk prediction. Additionally, we aim to build a risk calculator to provide the risk of C5 palsy.

METHODS

We identified adult patients who underwent instrumented cervical fusion at a tertiary care medical center between 2013 and 2020. The primary outcome was postoperative C5 palsy. We developed ensemble machine learning, standard machine learning, and logistic regression models predicting the risk of C5 palsy-assessing discrimination and calibration. Additionally, a web-based risk calculator was built with the best-performing model.

RESULTS

A total of 1024 patients were included, with 52 cases of C5 palsy. The ensemble model was well-calibrated and demonstrated excellent discrimination with an area under the receiver-operating characteristic curve of 0.773. The following features were the most important for ensemble model performance: diabetes mellitus, bipolar disorder, C5 or C4 level, surgical approach, preoperative non-motor neurologic symptoms, degenerative disease, number of fused levels, and age.

CONCLUSIONS

We report a risk calculator that generates patient-specific C5 palsy risk after instrumented cervical fusion. Individualized risk prediction for patients may facilitate improved preoperative patient counseling and risk stratification as well as potential intraoperative mitigating measures. This tool may also aid in addressing potentially modifiable risk factors such as diabetes and obesity.

Ultrasound Lancet-aided Translaminar Posterior Lumbar Approach to the Recesso-Foraminal Area: Technical Note

Extrusion and sequestration of the nucleus pulposus involving the spinal canal or the foramina/recesses complicates up to 28% of the lumbar disc herniations. The transpars/translaminar anatomical approach is well described and its advantages when handling with a lateral, foraminal extruded disc herniation are appreciated and recognized. Nevertheless, this approach presents several pitfalls such as the risk of disconnecting the pars interarticularis, which may cause segmental instability. This particular eventuality is because of the particular anatomical conformation of the pars interarticularis. Although already part of the modern surgical armamentarium for general, orthopedic, cranial and spinal surgeons, the use of the ultrasonic scalpel technique for such approach has never been discussed to date, to the best of our knowledge. The purpose of the present paper is therefore to introduce and describe the stepwise technique along with an extensive discussion of the facilitating role of the ultrasonic scalpel in the translaminar/transpars approach in the management of extruded disc herniation of the lumbar spine.

Morphology of cervical periradicular fibrous sheath and nerve roots in relation to postoperative C5 palsy

BACKGROUND CONTEXT

C5 palsy is a major complication of cervical spine surgery, however, its exact pathogenesis remains unclear. Some studies have shown that the superficial layer of the posterior longitudinal ligament extends laterally and forms the periradicular fibrous sheath (PFS), and envelopes the nerve roots. However, the anatomical relationship between the PFS and nerve root at each cervical level has not been fully revealed.

PURPOSE

To examine the difference of the PFS that covers the nerve root at each cervical level, and to consider its potential in the onset of postoperative C5 palsy.

STUDY DESIGN

Anatomical study of cervical dissection of 13 embalmed cadavers.

METHODS

Thirteen human formalin-fixed cadavers were dissected from posterior approach, and were observed their cervical nerves bilaterally from C3 to C8 (the total number of nerves was 156). The bare area length (BAL), which is the distance between the medial posterior edge of the PFS and the bifurcation of the nerve and dura mater, was measured by using electronic calipers. Thus, BAL is the uncovered area of the nerve root by the PFS. We examined whether BAL significantly varied at each cervical level.

RESULTS

We confirmed the PFS macro- and/or microanatomically in all cadavers. The average BAL gradually increased craniocaudally, and there was a significant step between that of C5 and C6 level.

CONCLUSION

The average BAL of the C5 root was significantly shorter than that of C6, C7, and C8, suggesting that C5 root was more tightly anchored. This could be one reason for C5 palsy, making C5 nerve root vulnerable to the traction caused by the postoperative spinal cord shift.

CLINICAL SIGNIFICANCE

This study provides clinicians an additional understanding of the anatomical factor of C5 palsy. Consideration of the anchoring effect of the PFS for nerve roots, release of the PFS could be a preventive procedure for C5 palsy.

An Experimental Rat Model of C5 Palsy Following Posterior Decompression Surgery of the Cervical Spine

STUDY DESIGN

Basic in vivo research.

OBJECTIVES

The aim of this study was to establish an animal model that is appropriate for analyzing the mechanisms of C5 palsy (C5P) and to clarify the structural and functional alterations of cervical roots following posterior decompression.

SUMMARY OF BACKGROUND DATA

Although C5P is one of the major complications of cervical surgery, the exact pathogenesis of C5P remains unclear partly because of the lack of an appropriate animal model. Tethering of the cervical roots due to posterior cord shift following posterior decompression is thought to be one of the possible factors that cause C5P.

METHODS

Twenty-eight Sprague-Dawley rats were divided into Group L (cervical laminectomy, N = 18) or Group S (sham surgery, N = 10) and examined up to postoperative day 14 (PO14). Posterior cord shift and the length of the anterior rootlets were quantified by computed tomography-myelogram images. Motor evoked potential (MEP) of the deltoid (C5, 6 innervated) and triceps brachii (C7-T1 innervated), mechanical allodynia, and grip strength of the forepaw (C7-T1 regulated) were measured.

RESULTS

All anterior rootlets were elongated as the cord gradually shifted posteriorly postoperatively. The elongation rate of the C6 anterior rootlets was the highest (142% at PO14). The MEP latency of the deltoid was significantly delayed throughout all postoperative time points. However, significant delay in the latency of the triceps brachii was observed only on postoperative day 10. The withdrawal threshold of the forepaw did not change; grip strength of the forelimb decreased at PO14.

CONCLUSION

This model was thought to be appropriate for analyzing the pathogenesis of C5P since our findings were comparable to the clinical course of C5P subsequent to posterior cervical decompression. Although a future study for clarifying histological and molecular alterations will be needed, tethering of the anterior rootlets due to posterior cord shift was suggested to be a probable mechanism causing C5P.Level of Evidence: 5.

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.

Nerve Transfers After Cervical Spine Surgery: Multi-Institutional Case Series and Review of the Literature

BACKGROUND

Up to 10% of cervical spine surgeries are complicated by postoperative weakness. Although many patients recover with nonoperative management, some require surgery for restoration of function.

OBJECTIVE

To present the indications and outcomes of patients undergoing nerve transfers after developing weakness secondary to cervical spine decompression.

METHODS

A retrospective review of patients from 2 academic medical centers who underwent nerve transfer for C5-6 root injury after cervical spine surgery was performed.

RESULTS

Of the 10 treated patients, 9 experienced recovery at last follow-up, demonstrating improvements in strength and motion in the affected muscles. Successful nerve transfers occurred between 3 and 8 months after the index spinal surgery and included spinal accessory nerve to suprascapular nerve, triceps branch to anterior division of the axillary nerve, and/or ulnar or median fascicles to motor branches of the musculocutaneous nerve. The unsuccessful patient underwent nerve transfer surgery approximately 11 months after the index operation and failed to obtain functional recovery.

CONCLUSIONS

Patients who experience C5-6 weakness after cervical spine surgery should be evaluated and considered for nerve transfer surgery if they have continued severe functional deficits at 6 months postoperatively. Earlier referral for nerve transfer is associated with improved functional outcomes in this cohort.

Timing of referral to peripheral nerve specialists in patients with postoperative C5 palsy

The objective of this study was to examine the association between electrophysiology data post-C5-palsy and referral to peripheral nerve surgeons (PNS) using a 15-year cohort of patients who underwent posterior cervical decompression. Endpoints included the associations of postoperative treatments employed with functional recovery and abnormal electrophysiology data. Of 77 included patients (median 64 yr; 68% male), 48% completely recovered. The most common treatments were physical therapy (90%), occupational therapy (34%), oral corticosteroids (18%), and PNS referral (17%). Baseline weakness did not associate with PNS referral or postoperative treatment strategy. None of the treatments predicted recovery, though patients with no [versus complete] recovery were more likely to be recommended for nerve transfers (22.2 vs 0%; p = 0.03). Abnormal electromyography data associated with PNS referral (p < 0.01), nerve transfer recommendation (p < 0.01), occupational therapy referral, and oral corticosteroid therapy. Abnormal findings on EMG obtained between 6-weeks and 6-months post-injury were the most strongly associated with peripheral nerve surgeon referral (p = 0.02) and nerve transfer recommendation (p < 0.01). These data suggest strategies for postoperative C5 palsy management are highly heterogeneous. None of the treatments employed significantly predicted the extent of functional recovery. However, patients with abnormal electrophysiology results were most likely to receive multimodal treatment, suggesting these results may significantly alter medical management of patients with postoperative C5 palsy. Early (6-week to 6-month) electrophysiology data may help to ensure that patients likely to benefit from nerve transfer procedures are referred to a PNS within the 9-12-month time frame associated with the best recovery of function.

Thoracic Spine Stenosis: Does Ultrasonic Osteotome Improve Outcome in Comparison to Conventional Technique?

INTRODUCTION

To investigate the efficacy of Ultrasonic Bone Scalpel (UBS) in thoracic spinal stenosis (TSS) in comparison to traditional technique.

MATERIAL AND METHODS

A total of 55 patients who had undergone conventional surgery (Group A) are compared with 45 patients of UBS (Group B) in TSS. The primary outcome measure of Modified Japanese Orthopaedic Association score (m JOA) with neurological complications and dural injury were assessed. Secondary outcome measures of total blood loss (TBL), time duration of surgery (ORT) and length of hospital stay (LHS) were analysed.

RESULTS

The pre-operative mJOA score 5.00(4.00-6.00) in the group A and 5.00(4.00-6.00) in the group B improved to 7.00(7.00-8.00) in the group A and 9.00(9.00-10.00) in the group B, respectively (P<0.001) at final average follow-up of 117.55 months for group A and 75.69 months in group B. More significant grade of myelopathy improvement and mJOA recovery rate (RR) were noted in group B. The TBL, ORT and LHS were more favourable in group B as compared to group A (p<0.0001). The group A had 9 (16.36%) neurological deficits compared to 2 (4.44%) in group B (p<0.001). Dural tears occurred in both groups (A=11, B=9). It was more frequent and not repairable in group A but without significant statistical difference.

CONCLUSION

UBS can reduce neurological deficits and improve outcomes in TSS. Secondarily, reduced blood loss, lesser surgical time and reduced LHS are significant added advantages of this new technology.

Effect of irrigation technique on the vertebral canal temperature during thoracolumbar hemilaminectomy in dogs: An ex vivo study

OBJECTIVE

To determine the influence of continuous and intermittent bolus irrigation on vertebral canal temperature during thoracolumbar hemilaminectomy.

STUDY DESIGN

Ex vivo study.

SAMPLE POPULATION

Ten canine cadavers.

METHODS

Six consecutive thoracolumbar hemilaminectomies starting at T12-13 with alternating left- or right-side selection, and alternating continuous or intermittent bolus irrigation were performed in each dog resulting in 30 hemilaminectomies per irrigation technique. Drilling was performed for 15 s followed by a 10-s pause and resumed until completion of hemilaminectomy. Continuous irrigation consisted of saline delivered at 15 ml/min during drilling. Bolus irrigation consisted of manual delivery of 10 ml saline during the pause. Temperatures were recorded with two sensors placed within the vertebral canal adjacent to target hemilaminectomy site and compared between techniques with a linear mixed model.

RESULTS

Intermittent bolus irrigation was associated with lower peak vertebral canal temperatures (mean 15.7°C; range 9.4-23.3°C) than continuous irrigation (mean 16.7°C; range 9.6-27.6°C, p = .003) (mean difference of 1.1°C, p = .006). Similarly, mean vertebral canal temperatures remained lower when hemilaminectomies were performed under intermittent rather than continuous irrigation (mean difference of 0.48°C, p = .006, linear mixed model).

CONCLUSION

Lower vertebral canal temperatures were maintained during hemilaminectomy with intermittent bolus rather than continuous irrigation.

CLINICAL SIGNIFICANCE

Both intermittent bolus and continuous irrigation are suitable to prevent elevations in canine vertebral canal temperature during hemilaminectomy.

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.

Use of electromyography to predict likelihood of recovery following C5 palsy after posterior cervical spine surgery

BACKGROUND

C5 palsy affects approximately 5% to 10% of patients undergoing cervical spine surgery. It has a significant negative impact on patient quality-of-life outcomes and healthcare costs. Although >80% of patients improve, some are left with persistent, debilitating deficits. Our objective was to examine if electrodiagnostic testing could be used to successfully identify patients likely to experience complete, partial, and no recovery.

METHODS

Patients undergoing posterior cervical decompression and fusion at a single institution over a 10-year period were identified. Those experiencing postoperative C5 palsy were included. Outcomes examined included motor recovery of the affected deltoid as a function of time, and changes in electrodiagnostic testing as a function of time since injury. Electrodiagnostic testing included electromyography and was sub-analyzed by time of acquisition postinjury. Deltoid strength was graded on manual motor testing using the 5-point medical research council grading system.

RESULTS

Of 77 patients experiencing C5 palsy, 29 had postoperative electrodiagnostic testing. Patients experiencing complete recovery on average achieved functional (4/5) strength by 6-weeks post injury and 4+ per 5 strength by 6-months. Those experiencing partial recovery only achieved antigravity strength (3/5) by 6-weeks and low-function (4-/5) strength by 6-months. Electrodiagnostic testing performed 6-weeks to 6-months postinjury demonstrated that those experiencing complete recovery were more likely to have normal motor unit (MU) recruitment than those experiencing partial (p<.001) or no recovery (p=.008). The presence of ≥2+ fibrillation on tests acquired ≤6-weeks of injury identified patients unlikely to experience any recovery with a positive predictive value (PPV) of 88.9%. The presence of normal MU recruitment on tests acquired 6-weeks to 6-months postinjury identified patients likely to experience complete recovery with a PPV of 87.5%.

CONCLUSIONS

Electrodiagnostic testing may be a valuable means of differentiating between patients with C5 palsy likely to experience complete, partial, or no recovery. Testing between 6-weeks and 6-months post onset may aid in identifying those least likely to have a complete recovery. No MUs at 4 to 6-months, or reduced units with strength that is not improving, portends a poor long-term outcome. In this population, peripheral nerve transfers may be considered sooner.

Risk factor analysis of surgery-related complications in primary cervical spine surgery for degenerative diseases using a surgeon-maintained database

AIMS

This study, using a surgeon-maintained database, aimed to explore the risk factors for surgery-related complications in patients undergoing primary cervical spine surgery for degenerative diseases.

METHODS

We studied 5,015 patients with degenerative cervical diseases who underwent primary cervical spine surgery from 2012 to 2018. We investigated the effects of diseases, surgical procedures, and patient demographics on surgery-related complications. As subcategories, the presence of cervical kyphosis ≥ 10°, the presence of ossification of the posterior longitudinal ligament (OPLL) with a canal-occupying ratio ≥ 50%, and foraminotomy were selected. The surgery-related complications examined were postoperative upper limb palsy (ULP) with a manual muscle test (MMT) grade of 0 to 2 or a reduction of two grade or more in the MMT, neurological deficit except ULP, dural tear, dural leakage, surgical-site infection (SSI), and postoperative haematoma. Multivariate logistic regression analysis was performed.

RESULTS

The significant risk factors (p < 0.050) for ULP were OPLL (odds ratio (OR) 1.88, 95% confidence interval (CI) 1.29 to 2.75), foraminotomy (OR 5.38, 95% CI 3.28 to 8.82), old age (per ten years, OR 1.18, 95% CI 1.03 to 1.36), anterior spinal fusion (OR 2.85, 95% CI 1.53 to 5.34), and the number of operated levels (OR 1.25, 95% CI 1.11 to 1.40). OPLL was also a risk factor for neurological deficit except ULP (OR 5.84, 95% CI 2.80 to 12.8), dural tear (OR 1.94, 95% CI 1.11 to 3.39), and dural leakage (OR 3.15, 95% CI 1.48 to 6.68). Among OPLL patients, dural tear and dural leakage were frequently observed in those with a canal-occupying ratio ≥ 50%. Cervical rheumatoid arthritis (RA) was a risk factor for SSI (OR 10.1, 95% CI 2.66 to 38.4).

CONCLUSION

The high risk of ULP, neurological deficit except ULP, dural tear, and dural leak should be acknowledged by clinicians and OPLL patients, especially in those patients with a canal-occupying ratio ≥ 50%. Foraminotomy and RA were dominant risk factors for ULP and SSI, respectively. An awareness of these risks may help surgeons to avoid surgery-related complications in these conditions. Cite this article: Bone Joint J 2021;103-B(1):157-163.

Fluid Lubrication and Cooling Effects in Diamond Grinding of Human Iliac Bone

Background and Objectives: Although there have been research on bone cutting, there have been few research on bone grinding. This study reports the measurement results of the experimental system that simulated partial laminectomy in microscopic spine surgery. The purpose of this study was to examine the fluid lubrication and cooling in bone grinding, histological characteristics of workpieces, and differences in grinding between manual and milling machines. Materials and Methods: Thiel-fixed human iliac bones were used as workpieces. A neurosurgical microdrill was used as a drill system. The workpieces were fixed to a 4-component piezo-electric dynamometer and fixtures, which was used to measure the triaxial power during bone grinding. Grinding tasks were performed by manual activity and a small milling machine with or without water. Results: In bone grinding with 4-mm diameter diamond burs and water, reduction in the number of sudden increases in grinding resistance and cooling effect of over 100 °C were confirmed. Conclusion: Manual grinding may enable the control of the grinding speed and cutting depth while giving top priority to uniform torque on the work piece applied by tools. Observing the drill tip using a triaxial dynamometer in the quantification of surgery may provide useful data for the development of safety mechanisms to prevent a sudden deviation of the drill tip.

Patterns of neurological deficits and recovery of postoperative C5 nerve palsy

OBJECTIVE

Paresis of the C5 nerve is a well-recognized complication of cervical spine surgery. Numerous studies have investigated its incidence and possible causes, but the specific pattern and character of neurological deficits, time course, and relationship to preoperative cord signal changes remain incompletely understood.

METHODS

Records of patients undergoing cervical decompressive surgery for spondylosis, disc herniation, or ossification of the longitudinal ligament, including the C4-5 level, were reviewed from a 15-year period, identifying C5 palsy cases. Data collected included age, sex, diabetes and smoking statuses, body mass index, surgical levels, approach, presence of increased cord signal intensity, and modified Japanese Orthopaedic Association (mJOA) scores. Narrative descriptions of the patterns and findings on neurological examination were reviewed, and complications were noted. The minimum follow-up requirement for the study was 12 months.

RESULTS

Of 642 patients who underwent cervical decompressive surgery, 18 developed C5 palsy (2.8%). The incidence was significantly lower following anterior surgery (6 of 441 [1.4%]) compared with that following cervical laminectomy and fusion (12 of 201 [6.0%]) (p < 0.001). There were 10 men and 8 women whose mean age was 66.7 years (range 54-76 years). The mean preoperative mJOA score of 11.4 improved to 15.6 at the latest follow-up examination. There were no differences between those with and without C5 palsy with regard to sex, age, number of levels treated, or pre- or postoperative mJOA score. Fifteen patients with palsy (83%) had signal changes/myelomalacia on preoperative T2-weighted imaging, compared with 436 of 624 (70%) patients without palsy; however, looking specifically at the C4-5 level, signal change/myelomalacia was present in 12 of 18 (67%) patients with C5 palsy, significantly higher than in the 149 of 624 (24%) patients without palsy (p < 0.00003). Paresis was unilateral in 16 (89%) and bilateral in 2 (11%) patients. All had deltoid weakness, but 15 (83%) exhibited new biceps weakness, 8 (44%) had triceps weakness, and 2 (11%) had hand intrinsic muscle weakness. The mean time until onset of palsy was 4.6 days (range 2-14 days). Two patients (11%) complained of shoulder pain preceding weakness; 3 patients (17%) had sensory loss. Recovery to grade 4/5 deltoid strength occurred in 89% of the patients. No patient had intraoperative loss of somatosensory or motor evoked potentials or abnormal intraoperative C5 electromyography activity.

CONCLUSIONS

Postoperative C5 nerve root dysfunction appears in a delayed fashion, is predominantly a motor deficit, and weakness is frequently appreciated in the biceps and triceps muscles in addition to the deltoid muscle. Preoperative cord signal change/myelomalacia at C4-5 was a significant risk factor. No patient had a detectable deficit in the immediate postoperative period or changes in intraoperative neuromonitoring status. Neurological recovery to at least that of grade 4/5 occurred in nearly 90% of the patients.

Usefulness of a high-speed surgical air drill in pubectomy during delayed anastomotic urethroplasty for pelvic fracture urethral injury

OBJECTIVES

Pubectomy is an ancillary technique used to increase exposure of the disrupted urethra and reduce anastomotic tension, which can be difficult for inexperienced surgeons. The objective of the present study was to illustrate the use of an air drill enabling delicate and precise bone resection in pubectomy for delayed anastomotic urethroplasty for pelvic fracture urethral injury.

METHODS

Between 2009 and 2019, 88 male patients underwent delayed anastomotic urethroplasty with pubectomy for pelvic fracture urethral injury. A total of 73 procedures used a high-speed surgical air drill (HiLAN HS; Aesculap, Tuttlingen, Germany) equipped with a short-hand piece. Operative time and blood loss in the air drill patient group (group 1) were compared with that of patients who underwent pubectomy using a rongeur and/or gouge (group 2, n = 15).

RESULTS

In 65 group 1 patients, urethroplasty was carried out using the perineal approach, with partial inferior pubectomy. Eight group 1 patients, whose proximal urethral end was displaced upward superior to the upper edge of pubis, underwent urethroplasty using the perineal and abdominal approach, with a superior partial pubectomy and supracrural urethral rerouting. No difficulty was encountered using the air drill in any of the cases. There was no significant difference in median operative time between the groups (group 1 256 min vs group 2 228 min; P = 0.31). The median blood loss in group 1 was significantly lower than group 2 (149 mL vs 453 mL; P < 0.0001).

CONCLUSIONS

Surgical air drills might facilitate pubectomy in patients undergoing delayed anastomotic urethroplasty for pelvic fracture urethral injury. This tool offers the advantage of a delicate bone resection with reduced blood loss.

Direct Involvement of Concomitant Foraminotomy for Radiculomyelopathy in Postoperative Upper Limb Palsy in Cervical Laminoplasty

OBJECTIVE

Although concomitant foraminotomy has been reported to increase the risk of postoperative upper limb palsy (ULP) in cervical laminoplasty, the specific effects of concomitant foraminotomy on ULP remain uncertain. This study aimed to clarify the effect of concomitant foraminotomy on ULP in cervical laminoplasty.

METHODS

We identified 19 patients who developed ULP after laminoplasty with concomitant foraminotomy for radiculomyelopathy with nerve root impingement (laminoplasty with concomitant foraminotomy group [F-group]) from 4080 patients who underwent primary cervical laminoplasty at 27 affiliated institutions between 2012 and 2018. An age- and sex-matched control group comprised patients who developed ULP after laminoplasty without concomitant foraminotomy (n = 76, 4:1 ratio with F-group). Collected data included the time of onset and distribution of ULP (side and level). The site of foraminotomy was recorded in the F-group.

RESULTS

The F-group showed a significantly higher incidence of ULP than the candidates for the control group (15.1% vs. 3.1%, P < 0.001). The site of foraminotomy was consistent with the distribution of ULP in 79% (15 of 19 patients) of the F-group. The F-group showed a significantly higher proportion of preoperative upper-limb muscle weakness (74% vs. 37%, P = 0.005) and early-onset ULP occurring by postoperative day 1 (63% vs. 33%, P = 0.02) compared with the control group.

CONCLUSIONS

Our results indicate that the foraminotomy procedure in the stenotic foramen is directly involved in ULP. Combined with a previous report suggesting that early-onset ULP is associated with thermal nerve damage, our results indicate that thermal nerve damage partly explains the increased incidence of ULP in the F-group.

Primary lumbar decompression using ultrasonic bone curette compared to conventional technique

PURPOSE

The ultrasonic bone curette (Bone Scalpel) is a novel technique in neurosurgery for bony dissection. This study aimed to evaluate its use against conventional techniques for primary lumbar decompression.

MATERIALS AND METHODS

This study was a retrospective cohort comparison, using Spine Tango Registry data. All patients undergoing a primary procedure for lumbar decompression secondary to degenerative disease during a 2-year period (2014-2016) were identified, split into age and gender matched cohorts utilising either bone scalpel or conventional techniques intra-operatively.

RESULTS

Ninety-three patients were identified within each cohort, which did not differ significantly in terms of age, gender, BMI, number of operative vertebral levels or seniority of the principal surgeon. The incidence of intra-operative blood loss >100 ml was significantly reduced within the bone scalpel cohort (16.1% bone scalpel, 34.4% conventional, p = 0.04). There was no difference in the incidence of iatrogenic dural breach (9.7% bone scalpel, 16.1% conventional, p = 0.27). There was no significant difference in pre-operative Core Outcomes Measures Index (COMI) between the cohorts (7.91 bone scalpel, 8.02 conventional, p = 0.67) and both cohorts demonstrated a significant reduction in mean COMI at 24 months (bone scalpel p = 0.004, conventional p = <0.001). No difference in mean COMI existed between either cohort at any point across the 24-month post-operative period (p = 0.18).

CONCLUSIONS

The use of ultrasonic bone curette for primary lumbar decompression is associated with reduced intra-operative blood loss compared to conventional techniques, alongside a comparable safety profile and equivalent patient reported outcomes.

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.

Investigation of the Effect of Process Parameters on Bone Grinding Performance Based on On-Line Measurement of Temperature and Force Sensors

This study investigates the effect of process parameters on neurosurgical bone grinding performance using a miniature surgical diamond wheel. Bone grinding is an important procedure in the expanded endonasal approach for removing the cranial bone and access to the skull base tumor via nasal corridor. Heat and force are generated during the grinding process, which may cause thermal and mechanical damage to the adjacent tissues. This study investigates the effect of grinding process parameters (including the depth of cut, feed rate, and spindle speed) on the bone grinding performance using temperature and force measurement sensors in order to optimize the grinding process. An orthogonal experimental design with a standard orthogonal array, L₉ (3³), is selected with each parameter in three levels. The experimental results have been statistically analyzed using the range and variance analysis methods in order to determine the importance order of the process parameters. The results indicate that the effect of the cutting depth on the grinding temperature and normal force is the largest, while the effect of the spindle speed on the tangential force is the largest. A high spindle speed would make the temperature rise to a certain extent; however, it significantly reduces the grinding force. At a certain spindle speed, a lower depth of cut and feed rate help to reduce the grinding temperature and force.

Laser fabrication of structural bone: surface morphology and biomineralization assessment

The current work explores the surface morphology of the laser-ablated bone using Yb-fiber coupled Nd:YAG laser (λ = 1064 nm) in continuous wave mode. As the laser-ablated region contains physiochemically modified carbonized and nonstructural region, it becomes unknown material for the body. Thus, biomineralization on such a laser-ablated region was assessed by in vitro immersion test in noncellular simulated body fluid. The presence of hydroxyapatite was detected in the precipitated mineral product using scanning electron microscopy equipped with energy dispersive spectroscopy, and X-ray diffraction analysis. The effect of varying laser parameters on distribution of surface morphology features was identified and its corresponding effect on biomineralization was studied.

Risk factors and preventive measures for C5 palsy after cervical open-door laminoplasty

OBJECTIVE

The pathomechanism of C5 palsy after cervical open-door laminoplasty is unknown despite the relatively common occurrence of this condition postoperatively. The aim of this study was to review clinical and imaging findings in patients with C5 palsy and to propose countermeasures for prevention of this complication.

METHODS

Between 2001 and 2018, 326 patients with cervical myelopathy underwent cervical laminoplasty at the authors' hospital, 10 (3.1%) of whom developed C5 palsy. Clinical features and radiological findings of patients with and without C5 palsy were analyzed.

RESULTS

In patients with C5 palsy, the width of the C5 intervertebral foramen was narrower and the position of the bony gutter was wider beyond the medial part of the C5 facet joint. The distance between the lateral side of the spinal cord and bony gutter was significantly greater in patients with C5 palsy. Patient characteristics, disease, cervical alignment, spinal canal expansion rate, anterior protrusion of the C5 superior articular process, high-intensity area in the spinal cord on T2-weighted MR images, posterior shift of the spinal cord, and operative time did not differ significantly between patients with and without C5 palsy.

CONCLUSIONS

The position of the bony gutter may have a central role in the pathomechanism of postoperative C5 palsy, especially in patients with a narrow C5 intervertebral foramen. Making an excessively lateral bony gutter might be a cause of C5 nerve root kinking at the intervertebral foramen. To prevent the occurrence of C5 palsy, it is important to confirm the medial line of the facet joint on the preoperative CT scan, and a high-speed burr should be started from inside of the facet joint and manipulated in a direction that allows the ligamentum flavum to be identified.

Percutaneous surgery of the forefoot compared with open technique - Functional results, complications and patient satisfaction

BACKGROUND

The use of percutaneous surgery is currently very common in foot and ankle surgery. The following prospective open-label patient-preference based study compares the traditional open technique versus the percutaneous surgery technique.

METHODS

The current study describes the results of 287 patients operated due to forefoot deformities either by open surgery or percutaneously. 96 of them underwent hallux valgus corrective surgery. The rest had lesser toe deformities. They were followed for a period of up to 24 months, to assess the surgery related pain, complications, and patient satisfaction. 112 patients were operated using a conventional open technique were compared to 175 patients treated using a percutaneous technique. Technique choice was left to the patient preference, though older patients with disturbed blood flow, were advised to undergo percutaneous surgery.

RESULTS

There is less pain using the percutaneous techniques relative to the open technique during the first 6 post-operative weeks. The 6, and 24 months FAOS score is similar in both groups. Complications are rare in any of the groups, with a significantly higher ASEPSIS score in the open surgery group.

CONDCLUSIONS

Percutaneous forefoot surgery appears safe and efficacious, demonstrating equal radiographic (in a 96 strong cohort of hallux valgus patients) and clinical results at six and 24 months. Due to less post-operative pain, and less infection risk it appears that percutaneous techniques are superior to open technique in some respects of treatment and indeed the PGIC of patients was significantly higher in this group.

Impact of Multifidus Muscle Swelling on C5 Palsy After Cervical Laminoplasty

STUDY DESIGN

Retrospective radiological analysis OBJECTIVE.: The aim of this study was to identify the effects of posterior cervical muscle swelling on C5 palsy (C5P) by evaluating early postoperative magnetic resonance (MR) images.

SUMMARY OF BACKGROUND DATA

Cervical laminoplasty is an established technique, but the risk of C5P after surgery has not been fully resolved. Studies have reported that lateral stretching and postoperative swelling of the multifidus muscle may cause stretching of the medial branches and cervical nerves.

METHODS

A total of 214 C5 nerves of 107 consecutive patients who underwent laminoplasty were examined. We reviewed their demographic and surgical data and radiographic and MR images as parameters, including the axial cross-sectional area (CSA) of the posterior muscles. The patients and C5 nerves were divided into C5P and non-C5P groups. The parameters and changes were compared between the two groups to examine correlations with C5P.

RESULTS

In demographic data, age, sex, history of smoking, diabetes mellitus, and preoperative Japanese Orthopedic Association scores were not significantly different between the groups. Only body mass index (BMI) was significantly higher in the C5P group. Regarding the surgical and imaging data, the number of laminoplasty, operative time, decompression trough width, cervical sagittal alignment, preoperative spinal cord rotation, and posterior shift of the spinal cord were not significantly different, but the multifidus CSA change ratio was significantly higher in the C5P group. Multiple logistic regression analyses revealed that the multifidus CSA change ratio and BMI were significant independent factors.

CONCLUSION

Multifidus swelling is associated with C5P, possibly through traction of the C5 nerve via the medial branches of the cervical dorsal rami. The medial branch is the shortest of the dorsal rami and may have the largest effect by traction force. Therefore, a gentle maneuver of the deep posterior muscles during surgery is a potential countermeasure to prevent C5P.

LEVEL OF EVIDENCE

3.

C5 palsy after C5/6/7 posterior foraminal decompression: A case report

RATIONALE

Although C5 palsy is a common complication of cervical spine surgery, its cause has not been confirmed. There are various hypotheses for its mechanism, including spinal cord impairment and nerve involvement. Therefore, prophylactic foraminotomy is one of the methods recommended for preventing C5 palsy. However, we describe a patient who experienced C5 palsy after microendoscopic foraminotomy between the left C5/6 and C6/7 levels.

PATIENT CONCERNS

A 43-year-old man presented with a 14-month history of progressive numbness in the left upper limb. We performed microendoscopic left foraminal decompressions at the C5/6/7 levels to treat the left C6 and C7 radiculopathy. On the postoperative day 1, we observed weak motor strength of the left deltoid, left biceps, and left forearm pronator, while the motor strength of the other muscles was normal.

DIAGNOSES

C5 palsy following C5/6/7 left foraminotomy.

INTERVENTION

Follow-up rehabilitation with muscle strength training and range of motion training.

OUTCOME

The patient recovered his motor strength completely within 3 months postoperatively.

LESSONS

In this case, the C5 palsy could not be adequately explained by the theory of nerve root impingement or disruption in blood circulation following spinal cord decompression. We hypothesized that the patient had drill heat-induced C5 palsy. Regarding the C5 palsy without C5 nerve root decompression, we hypothesize that the C5 palsy in C5/6/7 foraminotomy could be related to variations in the formation of the brachial plexus. Prophylactic foraminotomy for cervical posterior surgery should be performed with care, limiting its use in patients who are at a risk of developing C5 palsy because the prophylactic procedure can cause C5 palsy. We must also consider that even without decompression at the C4/5 level, there is a possibility of C5 palsy occurring.

Total uncinectomy of the cervical spine with an osteotome: technical note and intraoperative video

Total uncinate process resection or uncinectomy is often required in the setting of severe foraminal stenosis or cervical kyphosis correction. The proximity of the uncus to the vertebral artery, nerve root, and spinal cord makes this a challenging undertaking. Use of a high-speed burr or ultrasonic bone dissector can be associated with direct injury to the vertebral artery and thermal injury to the surrounding structures. The use of an osteotome is a safe and efficient method of uncinectomy. Here the authors describe their technique, which is illustrated with an intraoperative video.

Efficacy analysis of two surgical treatments for thoracic and lumbar intraspinal tumours

BACKGROUND

Surgery remains the main curative option for the treatment of intraspinal tumour. The purpose of the present study was to analyze the clinical outcomes of laminoplasty with process-lamina complex replantation compared with laminectomy with pedicle screw fixation for intraspinal tumours.

METHODS

In our retrospective analysis, 27 patients received tumour resection surgery by laminoplasty with reconstruction plate fixation and 32 patients received laminectomy with pedicle screw fixation. All patients were followed up for at least 1 year. Data, including surgical time, blood loss, volume of drainage, drainage time, hospital stay, complications, and neurological status were compared. In addition, imaging evaluation was also included.

RESULTS

Patients in the laminoplasty group had lower blood loss (laminoplasty group: 281.5 ± 130.2 mL; laminectomy group: 450.0 ± 224.3 mL; p = 0.001), shorter surgical time (laminoplasty group: 141.7 ± 26.2 min, laminectomy group: 175.3 ± 50.4 min; p = 0.003), lower volume of drainage (laminoplasty group: 1578.9 ± 821.7 mL, laminectomy group: 2621.2 ± 1351.0 mL; p = 0.001), shorter drainage time (laminoplasty group: 6.6 ± 2.5 days, laminectomy group: 9.7 ± 1.8 days; p = 0.000), and a shorter hospital stay (laminoplasty group: 16.9 ± 4.9 days, laminectomy group: 21.0 ± 4.4 days; p = 0.002) compared with patients in the laminectomy group. There were significant differences of oswestry dysfunction index (ODI) between the two groups at 12 months postoperatively (p = 0.034). The incidence of secondary spinal stenosis in the laminoplasty group was significantly reduced (p = 0.029).

CONCLUSIONS

Laminoplasty in intraspinal tumour resection has a lower blood loss and volume of drainage, shorter surgical time and hospital stay as advantages over the standard laminectomy technique. Moreover, laminoplasty can effectively avoid iatrogenic spinal canal stenosis and thus enhancing functional recovery of spinal cord.

An overview of thermal necrosis: present and future

Introduction: Many orthopaedic procedures require drilling of bone, especially fracture repair cases. Bone drilling results in heat generation due to the friction between the bone and the drill bit. A high-level of heat generation kills bone cells. Bone cell death results in resorption of bone around bone screws.Methods: We searched in the literature for data on parameters that influence drilling bone and could lead to thermal necrosis. The points of view of many orthopaedists and neurosurgeons based upon on previous practices and clinical experience are presented.Results: Several potential complications that lead to thermal necrosis are discussed and highlighted.Discussion: Even in the face of growing evidence as to the negative effects of heat induction during drilling, simple and effective methods for monitoring and cooling in real-time are not in widespread usage today. For that purpose, we propose some suggestions for the future of bone drilling, taking note of recent advances in autonomous robotics, intelligent systems and computer simulation techniques.Conclusions: These advances in prevention of thermal necrosis during bone drilling surgery are expected to reduce the risk of patient injury and costs for the health service.

The Efficacy of Ultrasonic Bone Scalpel for Unilateral Cervical Open-Door Laminoplasty: A Randomized Controlled Trial

BACKGROUND

In cervical open-door laminoplasty for cervical myelopathy, a high-speed rotatory drill and rongeurs are used to make unicortical troughs and bicortical openings in the laminae. The lamina is reflected at the trough to enlarge the spinal canal, followed by bone healing on the hinge side to stabilize laminoplasty. The ultrasonic bone scalpel (UBS) has been used due to theoretical advantages including a better hinge union rate, less soft tissue trauma, less neurological injury, and shorter operative time.

OBJECTIVE

To assess the superiority of UBS for hinge union compared to the drill through randomized controlled trial.

METHODS

In 190 randomly allocated cervical myelopathy patients, the trough and opening at the lamina were made using either the drill (n = 95) or UBS (n = 95) during 2015 to 2018. The primary outcome was the hinge union rate on 6-mo postoperative computed tomography. Secondary outcomes included the hinge union rate at 12 mo, the operative time, intraoperative/postoperative bleeding, neurological injury, complications, and clinical outcomes over a 24-mo follow-up.

RESULTS

Hinge union in all laminae was achieved in 60.0% (drill) and 43.9% (UBS) of patients at 6 mo (intention-to-treat analysis; P = .02; odds ratio, 2.1) and in 91.9% (drill) and 86.5% (UBS) at 12 mo. Dural injury only occurred in the drill group (2.1%), and the UBS group showed significantly less intraoperative bleeding (P < .01). The other secondary outcomes did not differ between groups.

CONCLUSION

The hinge union rate was inferior in the UBS group at 6 mo postoperatively, but UBS was efficacious in reducing dural injuries and bleeding.

Infrared thermography of high-speed grinding of bone in skull base neurosurgery

For skull base tumor removal neurosurgery, skull bone grinding is required. During this process, temperature rise occurs, which may result in an irrecoverable thermal damage. In the present research, temperature variations during bone grinding have been studied. Experimental tests have been conducted in 27 states in terms of the parameters of rotational speed (three states), feed rate (three states), and cutting depth (three states) on bovine femur bone samples. Attempts have been made to determine optimal processing conditions for minimizing thermal damage during the surgery through infrared thermography and measuring thermal variations of the bone. The results indicated that the temperature rise of the bone has a direct relationship with the parameters of rotational speed, feed rate, and cutting depth. In other words, with elevation of each of these parameters, temperature rise was also intensified. Out of the cutting parameters, rotational speed had the maximum impact on temperature rise, followed by cutting depth and feed rate. Therefore, to reduce the extent of thermal damage incurred to the neural tissue, the minimum values for the cutting parameters are proposed as follows: rotational speed = 45000 r min−1, feed rate = 20–30 mm min−1 with depth of cut = 0.25 mm, and feed rate = 20 mm min−1 with cutting depth = 0.50 mm.

Prophylactic perioperative dexamethasone decreases the incidence of postoperative C5 palsies after a posterior cervical laminectomy and fusion

BACKGROUND CONTEXT

Postoperative C5 palsy is a well-known complication of cervical decompression procedures. Studies have shown that posterior laminectomy and fusions confer the greatest risk of C5 palsy. Despite this, pharmacologic preventive measures remain unknown. We hypothesize that prophylactic perioperative dexamethasone (DEX) will decrease the rate of postoperative C5 palsy in patients undergoing a multilevel posterior cervical laminectomy and fusion.

PURPOSE

The purpose of this study was to assess the safety and efficacy of prophylactic perioperative DEX in decreasing the rate of postoperative C5 palsy.

DESIGN

This is a retrospective, single-institution clinical study.

PATIENT SAMPLE

The patient population included all patients undergoing multilevel posterior cervical laminectomy and instrumented fusion procedures for myeloradiculopathy or myelopathy, who also received a course of perioperative dexamethasone. Surgeries occurred between 2012 and 2017 at a single tertiary care center by a single surgeon with at least 1 year of follow-up. Patients who underwent decompression procedures other than multilevel posterior cervical laminectomy and instrumented fusions; had trauma, fracture; underwent decompression not including C5-level, insulin-dependent diabetes mellitus; and had documented adverse reactions to steroids were excluded.

OUTCOME MEASURES

Preoperative demographics and postoperative complications, including development of postoperative C5 palsy, were considered as outcome measures.

MATERIALS AND METHODS

A total of 189 consecutive patients who underwent multilevel posterior cervical laminectomy and instrumented fusion and received prophylactic perioperative DEX were reviewed. The rate of C5 palsy was investigated and compared with our historical control rate of C5 palsy before the institutional implementation of perioperative DEX. Demographics were reviewed, and risk factor stratification was analyzed. The safety of using DEX was investigated by examining postoperative complications. The clinical course of patients who developed C5 palsy was then reported.

RESULTS

Postoperative C5 palsy occurred in 5 of the 138 patients (3.6%) meeting the inclusion criteria. Patients receiving perioperative DEX had a significantly decreased rate of postoperative C5 palsy compared with those who did not (3.6% vs. 9.5%, p=.01). Age was the only risk factor that was significantly correlated with development of C5 palsy (72.71±7.76 vs. 61.07±10.59, p=.02). Infection, seroma, and wound complication rates were 2.8%, 2.17%, and 1.44%, respectively, in patients receiving prophylactic DEX. All five patients receiving DEX who developed C5 palsy recovered with no residual deficits at an average of 16.8 weeks postoperatively.

CONCLUSIONS

Perioperative prophylactic DEX therapy is a safe and effective way to decrease the incidence of C5 palsies in patients who undergo multilevel posterior laminectomy and fusion for myeloradiculopathy or myelopathy.

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.

Simple presurgical method of predicting C5 palsy after cervical laminoplasty using C5 nerve root ultrasonography

OBJECTIVE

The incidence of C5 palsy after cervical laminoplasty is approximately 5%. Because C5 palsy is related to cervical foraminal stenosis at the C4–5 level, the authors hypothesized that cervical foraminal stenosis can be diagnosed by examining the C5 nerve root (NR) using ultrasonography. The purpose of this study was to investigate whether postoperative C5 palsy could be predicted using ultrasonography.

METHODS

This study used a prospective diagnosis design. In total, 140 patients undergoing cervical laminoplasty were examined with ultrasound. The cross-sectional area (CSA) of the C5 NR was measured on both sides before surgery, and the incidence of postoperative C5 palsy was examined. The difference between the CSA of the patients with and without C5 palsy and the lateral differences in the C5 palsy group were determined.

RESULTS

The incidence of C5 palsy was 5% (7 cases). Symptoms manifested at a median of 5 days after surgery (range 1–29 days). The CSA of the C5 NR on the affected side was significantly enlarged in the C5 palsy group compared with that in the no–C5 palsy group (p = 0.001). In addition, in the patients who had C5 palsy, the CSA of the C5 NR was significantly enlarged on the affected side compared with that on the unaffected side (p = 0.02). Receiver operating characteristic analysis indicated that the best threshold value for the CSA of the C5 NR was 10.4 mm2, which provided 91% sensitivity and 71% specificity.

CONCLUSIONS

C5 palsy may be predicted preoperatively using ultrasound. The authors recommend the ultrasonographic measurement of the CSA of the C5 NR prior to cervical laminoplasty.

Case report of C5 palsy after C3-C6 posterior decompression and instrumented fusion in a patient undergoing inpatient rehabilitation

We report on a patient who had neurological deterioration attributed to C5 palsy post C3-C6 posterior decompression and instrumented fusion. A 60-year old man was admitted after a fall from an electric scooter. MRI of the cervical spine confirmed severe cervical spondylosis causing cord compression at C4/5 with associated cord oedema. He underwent posterior cervical decompressive surgery, and he remained neurologically stable post operatively. However, he subsequently developed acute left upper limb weakness limited to the C5 myotome 1 week after surgery whilst undergoing inpatient rehabilitation. A repeat MRI of the cervical spine did not reveal any new changes that may explain his symptoms. He was started on intravenous dexamethasone. C5 palsy after cervical decompressive surgery is not uncommon. There is no specific evidence-based treatment and it carries a generally good prognosis. The aim of this case report is to highlight this complication and raise awareness amongst physicians.