[Cause analysis and clinical intervention of C 5 palsy after cervical surgery]

Objective

To review the research progress of C 5 palsy (C 5P) after cervical surgery, providing new clinical intervention ideas for the C 5P patients.

Methods

The relevant literature domestically and abroad was extensively consulted and the latest developments in the incidence, risk factors, manifestations and diagnosis, prevention, and intervention measures of C 5P were systematically expounded.

Results

C 5P is characterized by weakness in the C 5 nerve innervation area after cervical decompression surgery, manifested as limited shoulder abduction and elbow flexion, with an incidence rate more than 5%, often caused by segmental spinal cord injury or mechanical injury to the nerve roots. For patients with risk factors, careful operation and preventive measures can reduce the incidence of C 5P. Most of the patients can recover with conservative treatment such as drug therapy and physical therapy, while those without significant improvement after 6 months of treatment may require surgical intervention such as foraminal decompression and nerve displacement.

Conclusion

Currently, there has been some advancement in the etiology and intervention of C 5P. Nevertheless, further research is imperative to assess the timing of intervention and surgical protocol.

A case of spinal cord infarction presenting with unilateral C5 palsy

A 75-year-old man developed sudden-onset tetraparesis preceded by chest pain. MRI of the cervical spine on the day of onset showed no abnormalities. Although his motor symptoms improved gradually, the weakness of the muscles innervated by the C5 nerve root persisted. Sensory and autonomic deficits were detected on an additional neurological examination, and follow-up MRI eight days after onset revealed spinal cord infarction at the right anterior horn at C3-C4. This case suggests that motor symptoms mimicking a radiculopathy could be present during the course of spinal cord infarction.

Risk factors for C5 palsy: a systematic review and multivariate analysis

OBJECTIVE

Postoperative C5 palsy (C5P) is a known complication in cervical spine surgery. However, its exact pathophysiology is unclear. The authors aimed to provide a review of the current understanding of C5P by performing a comprehensive, systematic review of the existing literature and conducting a critical appraisal of existing evidence to determine the risk factors of C5P.

METHODS

A systematic search of PubMed/MEDLINE (January 1, 2019, to July 2, 2021), EMBASE (inception to July 2, 2021), and Cochrane (inception to July 2, 2021) databases was conducted. Preestablished criteria were used to evaluate studies for inclusion. Studies that adjusted for one or more of the following factors were considered: preoperative foraminal diameter (FD) at C4/5, posterior spinal cord shift at C4/5, preoperative anterior-posterior diameter (APD) at C4/5, preoperative spinal cord rotation, and change in C2-7 Cobb angle. Studies were rated as good, fair, or poor based on the Quality in Prognosis Studies (QUIPS) tool. Random effects meta-analyses were done using methods outlined by Cochrane methodologists for pooling of prognostic studies. Overall quality (strength) of evidence was based on Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methods for prognostic studies. The protocol for this review was published on the PROSPERO (CRD264358) website.

RESULTS

Of 303 potentially relevant citations of studies, 12 met the inclusion criteria set a priori. These works provide moderate-quality evidence that preoperative FD substantially increases the odds of C5P in patients undergoing posterior cervical surgery. Pooled estimates across 7 studies in which various surgical approaches were used indicate that the odds of C5P approximately triple for each millimeter decrease in preoperative FD (OR 3.05, 95% CI 2.07-4.49). Preoperative APD increases the odds of C5P, but the confidence is low. Across 3 studies, each using different surgical approaches, each millimeter decrease in preoperative APD was associated with a more than 2-fold increased odds of C5P (pooled OR 2.51, 95% CI 1.69-3.73). Confidence that there is an association with postoperative C5P and posterior spinal cord shift, change in sagittal Cobb angle, and preoperative spinal cord rotation is very low.

CONCLUSIONS

The exact pathophysiological process resulting in postoperative C5P remains an enigma but there is a clear association with foraminal stenosis, especially when performing posterior procedures. C5P is also related to decreased APD but the association is less clear. The overall quality (strength) of evidence provided by the current literature is low to very low for most factors. Systematic review registration no.: CRD264358 (https://www.crd.york.ac.uk/prospero/).

Assessing Range of Motion Gap in Circumferential Surgery for Cervical Myelopathy due to Ossification of the Posterior Longitudinal Ligament

OBJECTIVE

Only a few studies have investigated the gap range of motion (gROM) in cervical myelopathy or deformity caused by ossification of the posterior longitudinal ligament (OPLL). The aim of this study is to investigate the correlation between the individual gROM and the postoperative clinical outcomes of patients with OPLL.

METHODS

Consecutive patients of cervical myelopathy caused by OPLL were analyzed retrospectively. The clinical outcomes were evaluated using Visual Analogue Scale scores of the neck and arm pain and the Japanese Orthopaedic Association scores. Radiologic measurements included flexion ROM (fROM), which was defined as the difference of cervical lordosis in flexion and neutral positions, extension ROM (eROM), defined as the difference between neutral and extension positions, and gROM, defined as the difference between fROM and eROM. Patients were grouped by the values of gROM, and comparisons of all outcomes were made between the groups.

RESULTS

A total of 42 patients underwent surgery. The patients with greater gROM did not differ from those with smaller gROM by demographic characteristics. During follow-up (mean 45.8 months), both groups had similar improvements, but the C5 palsy rates were higher in the greater gROM group than in the smaller gROM group (71% and 22%, P < 0.05).

CONCLUSIONS

Simultaneous circumferential decompression and fixation is an effective surgical option for patients with cervical myelopathy caused by OPLL. A higher rate of postoperative C5 palsy was observed in the patients with greater gROMs after surgery, although all patients presented with similar clinical improvements.

C5 nerve root palsy (without prior cervical decompression) case series: 9 patients with critical delay to presentation

BACKGROUND

Distinguishing between cervical nerve root and intrinsic shoulder pathology can be a difficult task given the overlapping and often coexisting symptoms.

OBJECTIVE

The objective of this study was to highlight the often-complicated presentation of these symptoms and the subsequent potential for delay in care regarding this subset of patients.

METHODS

A total of 9 patients, managed by one of two different surgeons, were identified with a history of C5 nerve root palsy. A chart review was conducted, and the following information was recorded: presenting complaint, time from symptom onset to diagnosis, time from symptom onset to presentation to a spine surgeon, first specialist seen for symptoms, non-spinal advanced imaging and treatment conducted before diagnosis, preoperative and postoperative exam, time to recovery, and type of surgery.

RESULTS

We observed an average time from onset of symptoms to presentation to a spine surgeon to be 31.6 weeks. These patients' time to full recovery after cervical decompression was 15 weeks.

CONCLUSION

: We observed a critical delay to presentation in this series of patients with C5 nerve palsy. C5 nerve palsy should remain an elemental part of the differential diagnosis in the setting of any shoulder or neck pain presenting with weakness.

Trends in cervical laminoplasty and 30-day postoperative complications: 10-year results from a retrospective, multi-institutional study of 1095 patients

PURPOSE

This study aimed to investigate the recent 10-year trends in cervical laminoplasty and 30-day postoperative complications.

METHODS

This retrospective multi-institutional cohort study enrolled patients who underwent laminoplasty for cervical spondylotic myelopathy (CSM) or ossification of the posterior longitudinal ligament. The primary outcome was the occurrence of all-cause 30-day complications. Trends were investigated and compared in the early (2008-2012) and late (2013-2017) periods.

RESULTS

Among 1095 patients (mean age, 66 years; 762 [70%] male), 542 and 553 patients were treated in the early and late periods, respectively. In the late period, patients were older at surgery (65 years vs. 68 years), there were more males (66% vs. 73%), and open-door laminoplasty (50% vs. 69%) was the preferred procedure, while %CSM (77% vs. 78%) and the perioperative JOA scores were similar to the early period. During the study period, the rate of preservation of the posterior muscle-ligament complex attached to the C2/C7-spinous process (C2, 89% vs. 93%; C7, 62% vs. 85%) increased and the number of laminoplasty levels (3.7 vs. 3.1) decreased. While the 30-day complication rate remained stable (3.9% vs. 3.4%), C5 palsy tended to decrease (2.4% vs. 0.9%, P = 0.059); superficial SSI increased significantly (0% vs. 1.3%, P = 0.015), while the decreased incidence of deep SSI did not reach statistical significance (0.6% vs. 0.2%).

CONCLUSIONS

From 2008 to 2017, there were trends toward increasing age at surgery and surgeons' preference for refined open-door laminoplasty. The 30-day complication rate remained stable, but the C5 palsy rate halved.

Does hinge sidedness influence laterality of C5 palsy after expansile open-door cervical laminoplasty?

OBJECTIVE

Cervical expansile open-door laminoplasties (EOLPs) have an open side and a hinge side, with the open side being bridged by grafts or miniplates. The authors explored the possibility that the open-door side might have a greater incidence of C5 palsy due to a greater stretch of the ipsilateral C5 nerve root.

METHODS

This study was a retrospective review of prospectively collected data over a period of 25 years specifically assessing surgical complications. Included were patients who underwent EOLP for myelopathy, radiculopathy, or mild central cord injuries (American Spinal Injury Association Impairment Scale [AIS] grade D). Exclusion criteria included preexisting C5 weakness; patients with AIS grade A, B, or C injury; and added instrumentation or additional surgical procedures. Patients were monitored postoperatively for C5 palsy or any other complications. A comparison group included patients who underwent cervical laminectomy and fusion (CLF).

RESULTS

A total of 327 laminoplasties were collected, and 31 patients were excluded because of severe spinal cord injury (AIS grades A-C), 3 for preoperative C5 weakness, and 21 for instrumentation or additional surgical procedures. Thus, 272 patients were analyzed with a mean age of 59.9 years (range 22-88 years). Diagnoses at presentation were cervical myelopathy (84.1%), central cord syndrome (7.2%), cervical myeloradiculopathy (3.4%), ossification of the posterior longitudinal ligament (1.9%), and other (3.4%). The most common complications were C5 palsy (n = 7, 2.6%) and wound infection (n = 7, 2.6%). Of the 7 cases of postoperative C5 palsies in this study, 6 occurred on the side of the open door. Of the C5 palsies, 2 were mild, 3 were moderate, and 2 were severe. Two of the 7 C5 palsies had a delayed (> 24 hours) onset. The C5 palsy incidence after CLF was 2.7% with no side preference.

CONCLUSIONS

C5 palsy after cervical decompression for myelopathy is a known occurrence, with a rate of 2.6% in the current study. The authors found that C5 palsies more commonly occur on the open side of the laminoplasty. This could be due to a greater manipulation of the nerve root on the side of the open door or greater stretch of the C5 root on the open-door side. If clinical symptoms and anatomical stenosis are symmetric, the authors recommend creating the laminoplasty hinge on the patient's dominant side to minimize potential loss of dominant proximal arm function.

Characteristics of Postoperative C5 Palsy Following Anterior Decompression and Fusion Surgery for Cervical Degenerative Disorders: Trends Associated with Advancements in Surgical Technique

OBJECTIVE

To investigate trends in the characteristics of postoperative C5 palsy following anterior decompression and fusion associated with advancements in this surgical procedure to treat cervical degenerative disorders.

METHODS

We included 801 consecutive patients who underwent anterior decompression and fusion for cervical degenerative disorders from 2006 to 2019 and investigated the incidence, onset, and prognosis of C5 palsy. In addition, we compared the incidence of C5 palsy with that found in our previous investigation.

RESULTS

The cases of 42 (5.2%) patients were complicated by C5 palsy. For patients with ossification of the longitudinal ligament (OPLL), 22 (12.4%) of 177 were complicated with C5 palsy, and the incidence was significantly higher than that in patients without OPLL (20 [3.2%] of 624, P < 0.01). The incidence of C5 palsy in patients without OPLL was significantly lower than that found in our previous investigation (P < 0.01). The incidence of C5 palsy in patients that required contiguous multilevel corpectomy was significantly higher in patients that required within a single corpectomy (P < 0.01). At 1-year follow-up, muscle strength in 3 (6.1%) of 49 limbs had not improved sufficiently.

CONCLUSIONS

With advancements in surgical techniques which allowed necessary and sufficient spinal cord decompression and avoided unnecessary corpectomy, the incidence of C5 palsy in patients without OPLL was decreased significantly. By contrast, for patients with OPLL, the incidence of C5 palsy was similar to the incidence found previously, perhaps because a broad and contiguous multilevel corpectomy was usually needed to decompress the spinal cord sufficiently.

Magnetic Resonance Imaging-CCCFLS Scoring System: Toward Predicting Clinical Symptoms and C5 Paralysis

STUDY DESIGN

A retrospective study.

OBJECTIVE

To develop a new MRI scoring system to assess patients' clinical characteristics, outcomes and complications.

METHODS

A retrospective 1-year follow-up study of 366 patients with cervical spondylosis from 2017 to 2021. The CCCFLS scores (cervical curvature and balance (CC), spinal cord curvature (SC), spinal cord compression ratio (CR), cerebrospinal fluid space (CFS). Spinal cord and lesion location (SL). Increased Signal Intensity (ISI) were divided into Mild group (0-6), Moderate group (6-12), and Severe group (12-18) for comparison, and the Japanese Orthopaedic Association (JOA) scores, visual analog scale (VAS), numerical rating scale (NRS), Neck Disability Index (NDI) and Nurick scores were evaluated. Correlation and regression analyses were performed between each variable and the total model in relation to clinical symptoms and C5 palsy.

RESULTS

The CCCFLS scoring system was linearly correlated with JOA, NRS, Nurick and NDI scores, with significant differences in JOA scores among patients with different CC, CR, CFS, ISI scores, with a predictive model (R2 = 69.3%), and significant differences in preoperative and final follow-up clinical scores among the 3 groups, with a higher rate of improvement in JOA in the severe group (P < .05), while patients with and without C5 paralysis had significant differences in preoperative SC and SL (P < .05).

CONCLUSIONS

CCCFLS scoring system can be divided into mild (0-6). moderate (6-12), severe (12-18) groups. It can effectively reflect the severity of clinical symptoms, and the improvement rate of JOA is better in the severe group, while the preoperative SC and SL scores are closely related to C5 palsy.

LEVEL OF EVIDENCE

III.

Treatment of C5 Palsy: An International Survey of Peripheral Nerve Surgeons

STUDY DESIGN

International survey.

OBJECTIVES

C5 palsy (C5P) is a neurological complication affecting 5-10% of patients after cervical decompression surgery. Most cases improve with conservative treatment; however, nearly 20% of patients may be left with residual deficits. Guidelines are lacking on C5P management and timing of surgical intervention. Therefore, we sought to survey peripheral nerve surgeons on their management of C5P.

METHODS

An online survey was distributed centered around a patient with C5P after posterior cervical decompression and fusion. Questions included surgeon demographics, diagnostic modalities, and timing and choice of operation. Responses were summarized and the chi-squared and Kruskal-Wallis H tests were used to examine differences across specialties.

RESULTS

A total of 154 surgeons responded to the survey, of which 59 (38%) indicated that they manage C5P cases. Average time prior to operating was 4.5 ± 2.2 months for complete injuries and 6.6 ± 3.2 months for partial injuries, with neurosurgeons significantly more likely to wait longer periods for complete (P = .01) and partial injuries (P = .03). Foraminotomies were selected by 19% of surgeons, while 92% selected nerve transfers. Transfer of the ulnar nerve to the musculocutaneous nerve was the most common choice (81%), followed by transfer of the radial nerve to the axillary nerve (58%).

CONCLUSION

Consensus exists among peripheral nerve surgeons on the use of nerve transfers for surgical treatment in cases with severe motor weakness failing to improve. Most surgeons advocate for early intervention in complete injuries. Disagreement concerns the type of nerve transfer employed, timing of surgery, and efficacy of foraminotomy.

Confirming a C5 Palsy with a Motor Evoked Potential Trending Algorithm during Insertion of Cervical Facet Spacers: A Case Study

The use of cervical facet spacers has shown favorable clinical results in the treatment of cervical spondylotic disease; however, there are limited data regarding neurological complications associated with the procedure. This case report demonstrates the specificity of multi-myotomal motor evoked potentials (MEPs) in detecting acute postoperative C5 palsy following placement of facet spacers. A posterior cervical fusion with decompression and instrumentation involving DTRAX (Providence Medical Technology; Lafayette, CA) was used to treat a patient with cervical stenosis and myelopathy. Intraoperative neurophysiological monitoring (IONM) consisting of MEPs, somatosensory evoked potentials (SSEPs), and free-run electromyography (EMG), was used throughout the procedure. Immediately following the placement of the DTRAX spacers at C4-5, a decrease in amplitudes from the right deltoid and biceps MEP recordings (>65%) was detected. All other IONM modalities remained stable; it is noteworthy that there was an absence of mechanically elicited EMG. A novel post-alert regression analysis trending algorithm of MEP amplitudes confirmed the visual alert. This warning along with an intraoperative computed tomography (CT) scan of the cervical spine subsequently resulted in the decision to remove one of the facet spacers. Surgical intervention did not result in recovery of the aforementioned MEP recordings, which remained attenuated at the time of wound closure. Postoperatively, the patient exhibited an immediate right C5 palsy (2/5). A post-surgery application of the trending algorithm demonstrated that it correlated to the visual alert until the end of monitoring.

Alteration of muscle activity during voluntary rehabilitation training with single-joint Hybrid Assistive Limb (HAL) in patients with shoulder elevation dysfunction from cervical origin

Shoulder elevation, defined here as arm raising, being essential for activities of daily living, dysfunctions represent a substantial burden in patients' lives. Owing to the complexity of the shoulder joint, the tightly coordinated muscular activity is a fundamental component, and neuromuscular impairments have devastating effects. A single-joint shoulder type version of the Hybrid Assistive Limb (HAL) allowing motion assistance based on the intention of the user via myoelectric activation has recently been developed, and its safety was demonstrated for shoulder rehabilitation. Yet, little is known about the physiological effects of the device. This study aims to monitor the changes in muscle activity and motion during shoulder HAL rehabilitation in several patients suffering from shoulder elevation dysfunction from cervical radicular origin. 8 patients (6 males, 2 females, mean age 62.4 ± 9.3 years old) with weakness of the deltoid muscle resulting from a damage to the C5 nerve root underwent HAL-assisted rehabilitation. We combined surface electromyography and three-dimensional motion capture to record muscular activity and kinematics. All participants showed functional recovery, with improvements in their Manual Muscle Testing (MMT) scores and range of motion (ROM). During training, HAL decreased the activity of deltoid and trapezius, significantly more for the latter, as well as the coactivation of both muscles. We also report a reduction of the characteristic shrugging compensatory motion which is an obstacle to functional recovery. This reduction was notably demonstrated by a stronger reliance on the deltoid rather than the trapezius, indicating a muscle coordination tending toward a pattern similar to healthy individuals. Altogether, the results of the evaluation of motion and muscular changes hint toward a functional recovery in acute, and chronic shoulder impairments from cervical radicular origin following shoulder HAL rehabilitation training and provide information on the physiological effect of the device.

Optimal timing of referral for nerve transfer surgery for postoperative C5 palsy

OBJECTIVE

Cervical nerve 5 palsy can occur following surgery for cervical spine pathology. The prognosis of C5 palsy is generally favorable, and most patients recover useful function. However, some patients do not recover useful strength. Nerve transfers are a potential effective treatment of postoperative severe C5 palsy. This study aimed to further delineate the natural history of recovery from postoperative C5 palsy, determine whether lack of recovery at specific time points predicts poor recovery prognosis, and thereby determine a reasonable time point for referral to a complex peripheral nerve specialist.

METHODS

The authors conducted a retrospective review of 72 patients who underwent surgery for cervical spondylosis and stenosis complicated by C5 palsy. Medical Research Council (MRC) motor strength grades were recorded preoperatively; immediately postoperatively; at discharge; and at 2 weeks, 3 months, 6 months, and 12 months postoperatively. Univariate and multivariate logistic regression models were used to identify demographic and clinical risk factors associated with recovery of useful strength after severe C5 palsy.

RESULTS

The mean patient age was 62.5 years, and 36.1% of patients were female. Thirty patients (41.7%) experienced severe C5 palsy with less than antigravity strength (MRC grade 2 or less) at discharge. Twenty-one (70%) of these patients recovered useful strength (MRC grade 3 or greater) at 12 months postoperatively, and 9 patients (30%) did not recover useful strength at 12 months. Of those patients with persistent severe C5 palsy at 3 months postoperatively, 50% recovered useful strength at 12 months. Of those patients with persistent severe C5 palsy at 6 months postoperatively, 25% recovered useful strength at 12 months. No patient with MRC grade 0 or 1 strength at 6 months postoperatively recovered useful strength. A history of diabetes was associated with the occurrence of severe C5 palsy. On multivariate analysis, female sex was associated with recovery of useful strength.

CONCLUSIONS

Most patients with severe C5 palsy recover useful strength in their C5 myotome within 12 months of onset. However, at 3 months postoperatively, patients with persistent severe C5 palsy had only a 50% chance of recovering useful strength by 12 months. Lack of recovery of useful strength at 3 months postoperatively is a reasonable time point for referral to a complex peripheral nerve center to establish care and to determine candidacy for nerve transfer surgery if severe C5 palsy persists.

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.

Iatrogenic Cervical Nerve Root Injury After Spine Surgery: How Nerve Surgeons Can Assist Spine Surgeons

BACKGROUND

Iatrogenic cervical nerve root injury may occur during cervical spine surgeries, which leads to upper limb palsy. The question of how a permanent iatrogenic upper limb palsy would be managed remains unclear. Recent developments of nerve transfer have led to a considerable interest in its applications. This study outlines a new reconstructive approach forupper limb palsy following cervical spine surgery using nerve transfer.

METHODS

In an attempt to reconstruct iatrogenic upper limb palsy, we performed nerve transfer in 4 patients with permanently lost functions. Medical Research Council Scale for Muscle Strength was used to assess muscle strength. Electromyography was performed to assess the reinnervation of the target muscles.

RESULTS

All patients underwent surgery between 7 and 12 months after primary injury. Spinal accessory nerve to suprascapular nerve transfer with or without transferring the long head of triceps branch of the radial nerve to anterior branch of the axillary nerve was used to reconstruct shoulder abduction in 2 patients. Double fascicular nerve transfer (a fascicle of the ulnar nerve to biceps branch and a fascicle of the median nerve to brachialis branch of the musculocutaneous nerve) was used to reconstruct elbow flexion in 3 patients. One patient had lost both his elbow flexion and shoulder abduction. After a mean of 10 months of follow-up, all patients improved to a muscle strength of M4 without donor deficit.

CONCLUSION

In our view, these results represent an excellent initial step toward the treatment of iatrogenic nerve root injury after spine surgery.

LEVEL OF EVIDENCE: 4

Influence of fixed titanium plate position on the effectiveness of open-door laminoplasty for cervical spondylotic myelopathy

BACKGROUND

During open-door laminoplasty, the position of the bone gutter is not fixed, and when the gutter migrates inward, the outer end of the titanium plate must be fixed on the lamina edge. It is unclear whether this will affect the clinical efficacy. This study aimed to observe the influence of the titanium plate fixation position on the effectiveness of open-door laminoplasty for cervical spondylotic myelopathy (CSM).

METHODS

A total of 98 patients with CSM who underwent open-door laminoplasty from August 2016 to October 2019 were included in this retrospective study. Fifty-five patients had the titanium plate fixed on the lateral mass (lateral mass group), and 43 patients had the titanium plate fixed on the lamina edge (lamina group). The opening angle, opening width, occurrence of hinge fracture, spinal cord drift distance, cervical curvature index (CCI), neurological function recovery (JOA score), neck function (NDI), C5 palsy and severity of axial symptoms were observed and compared between the two groups.

RESULTS

The opening angle in the lamina group was significantly larger than that in the lateral mass group, while the opening width and the spinal cord drift distance were significantly smaller than those in the lateral mass group (P < 0.05). The occurrence of hinge fracture in the lamina group was significantly higher than that in the lateral group (25.6% and 9.1%, respectively) (P < 0.05). The CCI was maintained well in both groups (P > 0.05), and there was no significant difference between the groups (P > 0.05). After surgery, the JOA score significantly increased in both groups (P < 0.05), and the neurological recovery rates were similar between the two groups (62.6% vs. 64.5%). The NDI score significantly decreased in both groups (P < 0.05), but the lateral mass group recovered to a greater degree than the lamina group (P < 0.05). The occurrence of C5 palsy was 2.3% in the lamina group and 14.5% in the lateral mass group, and there was a significant difference between the groups (P < 0.05). Postoperative axial symptom severity was significantly worse in the lamina group than in the lateral mass group (P < 0.05).

CONCLUSIONS

In open-door laminoplasty, it is feasible to fix the titanium plate on the lateral mass or to the lamina due to the same neurological function recovery. However, fixing it to the lamina will increase the opening angle and decrease the opening width, making the hinge prone to fracture and increasing the severity of postoperative axial symptoms.

Laminoplasty and simultaneous C2 semi-laminectomy with internal fixation in treating ossification of the posterior longitudinal ligament in cervical discs at C2 segment

OBJECTIVE

To explore the effect of open-door laminoplasty and simultaneous C2 semi-laminectomy with lateral mass screw fixation (LSLF) in treating ossification of the posterior longitudinal ligament (OPLL) in cervical discs at C2 segment.

METHODS

In this retrospective study, 76 patients diagnosed with OPLL in cervical discs at C2 segment from November 2016 to May 2019 were included. These patients were assigned into a LSLF group (n=41, LSLF surgery) and LF group (n=35, laminectomy and lateral mass screw fixation) according to the treatment they received. The surgery time and intraoperative blood loss were recorded. Improvements in neurological function (JOA score), cervical curvature index (CCI), spinal cord drift distance, cross-sectional area (CSA) of the posterior muscles from cervical spine, occurrence of C5 palsy, and severity of axial symptoms were evaluated between LSLF group and LF group.

RESULTS

Compared with LF group, the operative time was longer and blood loss volume was higher in LSLF group (P<0.05). No statistical difference was found in decompression width between LSLF group and LF group, while the drift distance of spinal cord in LSLF group was larger than that in LF group (P<0.05). No obvious differences were observed in anteroposterior dural sac diameter after the surgery between LSLF group and LF group. CSA in LF group decreased more than that in LSLF group (P<0.05). No remarkable difference was obtained in CCI at the final follow-up between LSLF group and LF group. The NDI score after surgery in the LSLF group was significantly decreased compared to LF group (P<0.05), while no differences were observed in JOA scores or the neurological recovery rate between LSLF group and LF group. The occurrence of C5 palsy in the LSLF group was 4.9%, which was less than that of LF group (20.0%). In contrast to LF group, postoperative axial symptoms in LSLF group were decreased (P<0.05).

CONCLUSION

Compared to LF, LSLF could better improve neck functions, and reduce the severity of axial symptoms and the occurrence of C5 palsy for patients with OPLL at C2 segment.

C5 Palsy of Patients with Proximal-Type Cervical Spondylotic Amyotrophy

Study Design

An observational cohort study design was adopted in this study.

Purpose

This study was designed to investigate preoperative factors that predict poor outcomes following surgery in patients with proximal-type cervical spondylotic amyotrophy (PCSA) using radiological findings.

Overview of Literature

We evaluated the preoperative factors associated with poor outcomes using electrophysiological and neurological findings. However, the preoperative factors associated with poor outcomes remained unclear.

Methods

Sixty patients with PCSA who underwent surgical treatment of the cervical spine were enrolled. The radiological findings on plain radiographs, computed tomography (CT), and magnetic resonance imaging (MRI) were evaluated. The cervical lordotic angles, C2-C7 sagittal vertical axis (SVA), and T1 slope were assessed on a lateral radiograph in the neutral position. CT was used to assess the width of the intervertebral foramen and the anterior protrusion of the superior articular process on the axial view. MRI was used to determine the number of levels of compression (NLC) and the presence of a high-intensity area in the spinal cord in the T2- weighted midsagittal view. The preoperative and postoperative strengths of the most atrophic muscles were evaluated using manual muscle testing. Improvements in strength were classified as excellent (five grades recovered), good (more than one grade recovered), fair (no improvement), or poor (worsened).

Results

The prevalence of C5 palsy was 17% (10/60). Patients with poor outcomes had higher NLC and Δ C2-C7 SVA than patients with excellent, good, and fair outcomes (p =0.015; odds ratio [OR], 5.758; 95% confidence interval [CI], 1.397-23.726 for a change of 10% and p =0.048; OR, 1.068; 95% CI, 0.992-1.141 for a change of 10%, respectively).

Conclusions

ΔC2-C7 SVA and NLC may be used as prognostic factors for achieving a poor outcome following surgery in patients with PCSA. More focus is needed on preventing the increase in ΔC2-C7 SVA.

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.

[Research progress of etiologies for C 5 palsy after cervical decompression]

Objective

To review the definition and possible etiologies for C ₅ palsy.

Methods

The literature on C ₅ palsy at home and abroad in recent years was extensively reviewed, and the possible etiologies were analyzed based on clinical practice experience.

Results

There are two main theories (nerve root tether and spinal cord injury) accounting for the occurrence of C ₅ palsy, but both have certain limitations. The former can not explain the occurrence of C ₅ palsy after anterior cervical spine surgery, and the latter can not explain that the clinical symptoms of C ₅ palsy is often the motor dysfunction of the upper limb muscles. Based on the previous reports, combining our clinical experience and research, we propose that the occurrence of C ₅ palsy is mainly due to the instrumental injury of anterior horn of cervical spinal cord during anterior cervical decompression. In addition, the C ₅ palsy following surgery via posterior approach may be related to the nerve root tether caused by the spinal cord drift after decompression.

Conclusion

In view of the main cause of C ₅ palsy after cervical decompression, it is recommended to reduce the compression of the spinal cord by surgical instruments to reduce the risk of this complication.

Complications associated with subaxial placement of pedicle screws versus lateral mass screws in the cervical spine: systematic review and meta-analysis comprising 1768 patients and 8636 screws

Lateral mass screw (LMS) fixation for the treatment of subaxial cervical spine instability or deformity has been traditionally associated with few neurovascular complications. However, cervical pedicle screw (CPS) fixation has recently increased in popularity, especially with navigation assistance, because of the higher pullout strength of the pedicle screws. To their knowledge, the authors conducted the first meta-analysis comparing the complication rates during and/or after CPS and LMS placement for different pathologies causing cervical spine instability. A systematic literature search of PubMed and Embase from inception to January 12, 2021 was performed to identify studies reporting CPS and/or LMS-related complications. Complications were categorized into intraoperative and early postoperative (within 30 days of surgery) and late postoperative (after 30 days from surgery) complications. All studies that met the prespecified inclusion criteria were pooled and cumulatively analyzed. A total of 24 studies were conducted during the time frame of the search and comprising 1768 participants and 8636 subaxially placed screws met the inclusion criteria. The CPS group experienced significantly more postoperative C5 palsy (odds ratio [OR] = 3.48, 95% confidence interval [CI] = 1.27-9.53, p < 0.05). Otherwise, there were no significant differences between the LMS and CPS groups. There were no significant differences between the CPS and LMS groups in terms of neurovascular procedure-related complications other than significantly more C5 palsy in the CPS group.

C6 nerve root palsy after double-door cervical laminoplasty

Background:

This study correlated the relationship between postoperative C6 nerve root palsies and various patient-related clinical, radiographic, and surgical parameters.

Methods:

The medical records of 318 patients undergoing double-door cervical laminoplasty for myelopathy were reviewed. Twelve (3.8%) had postoperative C6 nerve root palsies. Their clinical, radiographic, and surgical procedures were analyzed looking for a correlation/explanation for these new C6 root deficits.

Results:

The following factors correlated with patients’ developing new postoperative C6 nerve root deficit following double-door cervical laminoplasty; a high correlation with additional C5 palsies, narrower C6 intervertebral foraminal widths, greater anterior protrusions of the C6 articular process, and larger posterior shifts of the spinal cord on magnetic resonance (MR) between the C4/C5-C6/C7 levels.

Conclusion:

Factors correlating with the new onset of C6 nerve root palsies following double-door cervical laminoplasty included; a high correlation with new C5 palsies, more severe foraminal stenosis, greater anterior protrusions of the C6 articular process, and more extensive dorsal spinal cord migration.

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.

C5 palsy after cervical laminectomy: natural history in a 10-year series

BACKGROUND CONTEXT

C5 palsy is a well-known complication following cervical laminectomy, however the cause of this complication remains elusive, with many studies providing conflicting reports on prognosis and the impact of specific risk factors.

PURPOSE

To describe the natural history of and risk factors for C5 palsy after first time cervical laminectomy involving C4 and/or C5, in a large series with a high rate of postoperative palsy.

STUDY DESIGN/SETTING

This is a retrospective case series.

PATIENT SAMPLE

Patients undergoing first time cervical laminectomy for degenerative spine pathologies at a single institution between January 2008 and July 2018. Adult patients were included if a complete laminectomy was performed at C4 or C5 for degenerative pathology and pre- and postoperative upright lateral x-rays were performed.

OUTCOME MEASURES

The primary outcome measure was postoperative C5 palsy, defined as a decrease in strength of at least one point in deltoid and/or biceps within 30 days of operation. The secondary outcome measure was recovery of function.

METHODS

A retrospective database of patients who underwent posterior cervical spine surgery was created and further focused by utilizing specific Common Procedural Technology (CPT) codes associated with our desired patient population. Patients were excluded from our study if they had inadequate pre- and postoperative imaging, as well as patients with a history of prior cervical spine surgery, concurrent anterior surgery, intradural pathology, spinal tumor, or spinal trauma. Patient history, surgical specifics, and neurologic function were recorded.

RESULTS

A total of 190 patients were treated by 13 surgeons. 53 (27.9%) developed C5 palsy postoperatively. Of patients with C5 palsy, 40 (75.5%) recovered to baseline strength, 46 (86.6%) had at least grade 4 strength at last follow up, and 4 (7.5%) had strength worse than baseline and motor grade less than 4. Median time to recovery was 2.0 (IQR: 0.18 to 8.24) months. Age, gender, preoperative motor score, number of levels decompressed, smoking history, and comorbidities were not associated with a significant increase in the odds of C5 palsy. Risk of C5 palsy increased by 35% for every additional level fused below C4.

CONCLUSION

The risk of C5 palsy is increased with instrumentation caudal to C5 in operations addressing degenerative cervical pathology. This should be taken into consideration during operative planning. Overall prognosis of C5 palsy is good; however, incidence of this condition may be greater than previously reported.

Impact of morphological restoration of the spinal cord from the preoperative to early postoperative periods on C5 palsy development

OBJECTIVE

C5 palsy (C5P) is a known complication of cervical decompression surgery. The tethering effect of the C5 nerve root following the posterior shift of the spinal cord is the most accepted pathologic mechanism for C5P development; however, this mechanism cannot fully explain C5P by itself in clinical practice. Separately, some studies have suggested that preoperative severe spinal cord compression and postoperative morphological changes in the spinal cord affect C5P development; however, no previous study has quantitatively addressed these possibilities. The aim of this study was to examine whether spinal cord morphology and morphological restoration after surgery affect C5P development.

METHODS

The authors reviewed consecutive patients with degenerative cervical myelopathy who underwent laminoplasty including the C3-4 and C4-5 intervertebral disc levels. All participants underwent MRI both preoperatively and within 4 weeks postoperatively. To assess the severity of spinal cord compression, the compression ratio (CR; spinal cord sagittal diameter/transverse diameter) was calculated. As an index of morphological changes in the spinal cord during the early postoperative period, the change rate of CR (CrCR, %) was calculated as CRwithin 4 weeks postoperatively/CRpreoperatively × 100. These measurements were performed at both the C3-4 and C4-5 intervertebral disc levels. The study cohort was divided into C5P and non-C5P (NC5P) groups; then, CR and CrCR, in addition to other radiographic variables associated with C5P development, were compared between the groups.

RESULTS

A total of 114 patients (mean age 67.6 years, 58.8% men) were included in the study, with 5 and 109 patients in the C5P and NC5P groups, respectively. Preoperative CR at both the C3-4 and C4-5 levels was significantly lower in the C5P group than in the NC5P group (0.35 vs 0.44, p = 0.042 and 0.27 vs 0.39, p = 0.021, respectively). Patients with C5P exhibited significantly higher CrCR at the C3-4 level than those without (139.3% vs 119.0%, p = 0.046), but the same finding was not noted for CrCR at the C4-5 level. There were no significant differences in other variables between the groups.

CONCLUSIONS

This study reveals that severe compression of the spinal cord and its greater morphological restoration during the early postoperative period affect C5P development. These findings could support the involvement of segmental cord disorder theory, characterized as the reperfusion phenomenon, in the pathomechanism of C5P, in addition to the tethering effect.

A significant association between C5 nerve sheath tumors and new postoperative weakness

OBJECTIVE

The objective of this study was to determine if patients with nerve sheath tumors affecting the C5 spinal nerve are at greater risk for postoperative weakness than those with similar tumors affecting other spinal nerves contributing to the brachial plexus.

METHODS

A retrospective chart review (1998-2020)identified patients with pathologically confirmed schwannomas or neurofibromas from the C5 to T1 nerves. Patients with plexiform nerve sheath tumors, tumors involving more than 1 nerve, and malignant peripheral nerve sheath tumors were excluded. Collected variables included basic demographics, tumor dimensions, its location relative to the dura, involved nerve level, surgical approach, extent of resection, presenting symptoms, postoperative neurological deficits, and recurrence rate.

RESULTS

Forty-six patients (23 men, 23 women) were identified for inclusion in the study with an average age of 47 ± 17 years, BMI of 28 ± 5 kg/m2, and follow-up of 32 ± 45 months. Thirty-nine patients (85%) had schwannomas and 7 (15%) had neurofibromas. Tumors involved the C5 (n = 12), C6 (n = 11), C7 (n = 14), C8 (n = 6), and T1 (n = 3) nerves. Multivariable logistic regression analysis with an area under the curve of 0.85 demonstrated C5 tumor level as an independent predictor of new postoperative weakness (odds ratio 7.4, p = 0.028). Of those patients with new postoperative weakness, 75% improved and 50% experienced complete resolution of their motor deficits.

CONCLUSIONS

Patients with C5 nerve sheath tumor resections are at higher odds of new postoperative weakness. This may be due to the predominant single innervation of shoulder muscle targets in contrast to other upper extremity muscles that receive input from 2 or more spinal nerves. These findings are important for clinical decision-making and preoperative patient counseling.

Cervical laminoplasty with unilateral C4-5 foraminotomy: Technical note and case series

OBJECTIVE

The open-door laminoplasty technique is widely used in the treatment of multilevel cervical myelopathy. Despite the satisfactory functional and radiological results of this technique, postoperative C5 palsy is still a severe and disabling complication with a variable incidence in the literature. The objective of this article is to describe and demonstrate the surgical technique step by step with the addition of unilateral C4-5 foraminotomy and to evaluate the results obtained to date, with special emphasis on C5 palsy.

MATERIAL AND METHODS

Retrospective study of 20 patients operated on for cervical myelopathy using the "extended" laminoplasty technique, which is described step by step.

RESULTS

Between January 2013 and April 2019, 20 patients were operated on using the extended laminoplasty technique. Only one patient (5%) presented postoperative C5 palsy. The postoperative recovery rate of the modified JOA (Japanese Orthopaedic Association) score was 54.5%, similar to that observed in other series.

CONCLUSION

The extended cervical laminoplasty technique with unilateral C4-5 foraminotomy was developed and demonstrated for the prevention of C5 palsy. The results were analysed and an incidence of C5 palsy coinciding with the lowest percentage reported in the literature was obtained. A prospective randomised study would be useful to assess the role of preventive unilateral C4-5 foraminotomy.

Prediction of the risk of C5 palsy after posterior laminectomy and fusion with cervical myelopathy using a support vector machine: an analysis of 184 consecutive patients

Background

This study aimed to predict C5 palsy (C5P) after posterior laminectomy and fusion (PLF) with cervical myelopathy (CM) from routinely available variables using a support vector machine (SVM) method.

Methods

We conducted a retrospective investigation based on 184 consecutive patients with CM after PLF, and data were collected from March 2013 to December 2019. Clinical and imaging variables were obtained and imported into univariable and multivariable logistic regression analyses to identify risk factors for C5P. According to published reports and clinical experience, a series of variables was selected to develop an SVM machine learning model to predict C5P. The accuracy (ACC), area under the receiver operating characteristic curve (AUC), and confusion matrices were used to evaluate the performance of the prediction model.

Results

Among the 184 consecutive patients, C5P occurred in 26 patients (14.13%). Multivariate analyses demonstrated the following 4 independent factors associated with C5P: abnormal electromyogram (odds ratio [OR] = 7.861), JOA recovery rate (OR = 1.412), modified Pavlov ratio (OR = 0.009), and presence of C4C5 foraminal stenosis (OR = 15.492). The SVM model achieved an area under the receiver operating characteristic curve (AUC) of 0.923 and an ACC of 0.918. Additionally, the confusion matrix showed the classification results of the discriminant analysis.

Conclusions

The designed SVM model presented satisfactory performance in predicting C5P from routinely available variables. However, future external validation is needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02476-5.

Radiographic Measures of Spinal Alignment Are Not Predictive of the Development of C5 Palsy Following Anterior Cervical Discectomy and Fusion Surgery

BACKGROUND

Postoperative C5 palsy is a common complication following cervical decompression, occurring more frequently after posterior-based procedures. It has been theorized that this is the result of C5 nerve stretch resulting from spinal cord drift with these procedures. As such, it is thought to be less common after anterior cervical decompression and fusion (ACDF). However, no consensus has been reached on its true etiology. The purpose of this study is to assess the rate of C5 palsy following ACDF and to determine whether any radiographic or demographic parameters were predictive of its development.

METHODS

Two hundred and twenty-six patients who received ACDF between September 2015 and September 2016 were reviewed, and 122 were included in the final analysis. Patient demographic, surgical, and radiographic data were analyzed, including preoperative and postoperative radiographic and motor examination results. The Mann-Whitney U test was used to compare continuous variables between independent groups, and Fisher's exact test was used to compare categorical variables between groups.

RESULTS

Seven patients developed a C5 palsy in the postoperative period, an incidence rate of 5.7%. Among the radiographic parameters evaluated, there were no statistically significant differences between the C5 palsy and nonpalsy groups. Additionally, there were no statistically significant differences in age, patient sex, or numbers of vertebral levels fused between groups.

CONCLUSIONS

Ultimately, we did not identify any statistically significant demographic or radiographic predictive factors for the development of C5 palsy following ACDF surgery.

LEVEL OF EVIDENCE

3.

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.

Preoperative electrophysiologic assessment of C5-innervated muscles in predicting C5 palsy after posterior cervical decompression

PURPOSE

To investigate the feasibility of both needle electromyography (EMG) and proximal nerve conduction studies (NCS) in predicting C5 palsy after posterior cervical decompression.

METHODS

This study included 192 patients with cervical myelopathy undergoing laminoplasty or laminectomy. Preoperatively, all patients accepted bilateral needle EMG detection and proximal NCS that consisted of supramaximally stimulating Erb's point and recording compound muscle action potential (CMAP) from bilateral deltoid.

RESULTS

In the present study, 11 (11/192, 5.7%) patients developed unilateral C5 palsy after operation, and more patients with C5 palsy showed abnormal spontaneous activity in C5-innervated muscles compared to those without C5 palsy (8/11 vs. 16/181, p < 0.05). The sensitivity and specificity of spontaneous activity in C5-innervated muscles in predicting postoperative C5 palsy were 72.7% and 91.2%, respectively. Furthermore, there were significant left-to-right differences of deltoid CMAP amplitudes between the patients with and without C5 palsy (p < 0.05), and this measurement was also demonstrated to be useful for distinguishing patients with C5 palsy from cases without C5 palsy by receiver operating characteristic (ROC) curve analysis (cut-off value: 2.1 mV, sensitivity: 63.6%; specificity: 95.0%). In addition, the sensitivity and specificity of a series application of these two measurements were 63.6% and 100.0%, respectively.

CONCLUSIONS

The findings of this study support the hypothesis that pre-existing progressive C5 root injury may be a risk factor for C5 palsy after posterior cervical decompression. Clinically, the estimation of NCS and needle EMG in C5-innervated muscles may provide additional useful information for predicting C5 palsy after cervical spinal surgery.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

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.

Cervical laminoplasty with unilateral C4-5 foraminotomy: Technical note and case series

OBJECTIVE

The open-door laminoplasty technique is widely used in the treatment of multilevel cervical myelopathy. Despite the satisfactory functional and radiological results of this technique, postoperative C5 palsy is still a severe and disabling complication with a variable incidence in the literature. The objective of this article is to describe and demonstrate the surgical technique step by step with the addition of unilateral C4-5 foraminotomy and to evaluate the results obtained to date, with special emphasis on C5 palsy.

MATERIAL AND METHODS

Retrospective study of 20 patients operated on for cervical myelopathy using the "extended" laminoplasty technique, which is described step by step.

RESULTS

Between January 2013 and April 2019, 20 patients were operated on using the extended laminoplasty technique. Only one patient (5%) presented postoperative C5 palsy. The postoperative recovery rate of the modified JOA (Japanese Orthopaedic Association) score was 54.5%, similar to that observed in other series.

CONCLUSION

The extended cervical laminoplasty technique with unilateral C4-5 foraminotomy was developed and demonstrated for the prevention of C5 palsy. The results were analysed and an incidence of C5 palsy coinciding with the lowest percentage reported in the literature was obtained. A prospective randomised study would be useful to assess the role of preventive unilateral C4-5 foraminotomy.

Can prophylactic C4/5 foraminotomy prevent C5 palsy after cervical laminoplasty with and without posterior instrumented fusion with maximal expansion?

OBJECTIVE

To prospectively examine whether laminoplasty with maximal expansion induces C5 palsy, even with prophylactic bilateral C4/5 foraminotomy.

METHODS

Thirty-five consecutive patients with cervical myelopathy underwent laminoplasty (n = 19: LP group) or posterior decompression and fusion (n = 16: PDF group) with maximal expansion. Prophylactic bilateral C4/5 foraminotomy was performed alternately in consecutive five patients undergoing each type of surgery. In each type of surgery, the first and third consecutive five patients did not undergo foraminotomy (NF subgroup: 20 patients), while the second and fourth consecutive five patients underwent foraminotomy (F subgroup: 15 patients). The widths between the gutters was equivalent to the diameter of the spinal canal, and an inclination angle of the lamina of approximately 90° was created during laminoplasty. The incidence and severity of postoperative C5 palsy were investigated. Patients with a manual muscle testing score for the deltoid muscle and/or biceps brachii muscle of ≤ 2 were diagnosed with severe palsy.

RESULTS

The respective incidences of C5 palsy in the F and NF subgroups were 33% and 20% in the LP group and 50% and 20% in the PDF group. Severe palsy occurred in 67% and 0% of patients who had developed palsy in F and NF subgroups, respectively, in the LP group, and in 100% of patients in the PDF group. Furthermore, 40% of the patients with severe palsy took more than 6 months to recover.

CONCLUSIONS

Laminoplasty with maximal expansion induced C5 palsy in both the LP and PDF groups, even with the addition of prophylactic bilateral C4/5 foraminotomy.

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.

Foraminal Ligaments Tether Upper Cervical Nerve Roots: A Potential Cause of Postoperative C5 Palsy

Background  Nerve root tethering upon dorsal spinal cord (SC) migration has been proposed as a potential mechanism for postoperative C5 palsy (C5P). To our knowledge, this is the first study to investigate this relationship by anatomically comparing C5–C6 nerve root translation before and after root untethering by cutting the cervical foraminal ligaments (FL).

Objective  The aim of this study is to determine if C5 root untethering through FL cutting results in increased root translation.

Methods  Six cadaveric dissections were performed. Nerve roots were exposed via C4–C6 corpectomies and supraclavicular brachial plexus exposure. Pins were inserted into the C5–C6 roots and adjacent foraminal tubercle. Translation was measured as the distance between pins after the SC was dorsally displaced 5 mm before and after FL cutting. Clinical feasibility of FL release was examined by comparing root translation between standard and extended (complete foraminal decompression) foraminotomies. Translation of root levels before and after FL cutting was compared by two-way repeated measures analysis of variance. Statistical significance was set at 0.05.

Results  Significantly more nerve root translation was observed if the FL was cut versus not-cut, p  = 0.001; no difference was seen between levels, p  = 0.33. Performing an extended cervical foraminotomy was technically feasible allowing complete FL release and root untethering, whereas a standard foraminotomy did not.

Conclusion  FL tether upper cervical nerve roots in their foramina; cutting these ligaments untethers the root and increases translation suggesting they could be harmful in the context of C5P. Further investigation is required examining the value of root untethering in the context of C5P.

Improvement in the results of the simple-foot-tapping test and cross-sectional area of the dural sac in patients with C5 palsy after posterior cervical spine surgery

INTRODUCTION

The smaller cross-sectional areas of the dural sacs in patients without C5 palsy after posterior cervical spine surgery may lead to less neurological improvement.

OBJECTIVES

The aim of this retrospective study was to clarify the differences in the cross-sectional area of the dural sac in the cervical spine and neurological improvement in patients with and without C5 palsy after posterior cervical spinal surgery.

METHODS

We retrospectively evaluated the postoperative cross-sectional areas of the dural sacs and neurological outcomes in patients with and without C5 palsy after posterior cervical spine surgery. We compared the postoperative cross-sectional areas of the dural sac at C4/5 and C5/6 on magnetic resonance images between the C5 palsy group (n = 19) and the no-C5 palsy group (n = 84) after posterior cervical spinal surgery 1 year postoperatively. Performance tests, namely, the 10-s grip-and-release test and the 10-s single-foot-tapping (FT) test, were compared between the two groups.

RESULTS

Postoperative cross-sectional areas of the dural sac at C4/5 and C5/6 (233.3 mm² and 226.6 mm², respectively) in the C5 palsy group were significantly larger (P = 0.0036 and P = 0.0039, respectively) than those (195.0 mm² and 193.8 mm², respectively) in the no-C5 palsy group. Postoperative gain in the grip-and-release test was similar between the two groups. Postoperative gain in the FT test (4.9 times) in the C5 palsy group was significantly larger (P = 0.0060) than that (1.8 times) in the no-C5 palsy group.

CONCLUSIONS

In the C5 palsy group 1 year after posterior cervical spine surgery, the cross-sectional areas of the dural sac were larger, and the 10-s single FT test improved noticeably.

Spinal cord float back is not an independent predictor of postoperative C5 palsy in patients undergoing posterior cervical decompression

BACKGROUND

Of the more than 30,000 posterior cervical spine fusions performed annually, 7%-12% will be complicated by postoperative C5 palsy, a condition characterized by new-onset deltoid weakness with or without C5 dermatomal findings and biceps weakness. Posterior translation of the cervical spinal cord has been proposed as a risk factor for this complication.

PURPOSE

To evaluate if C5 palsy can be predicted by spinal cord float back.

STUDY DESIGN/SETTING

Retrospective cohort.

PATIENT SAMPLE

Patients ≥18 years of age undergoing posterior cervical decompression between 2002 and 2017 for degenerative cervical spine pathologies.

OUTCOME MEASURES

Occurrence of C5 palsy as evaluated by manual motor testing (MMT).

METHODS

We recorded baseline neurological status, operative notes, details of postoperative course, and both pre- and postoperative magnetic resonance imaging images. Float back was defined by the change in the distance between the spinal cord and posterior face of the C4/5 annulus from preoperative to postoperative imaging. C5 palsy was defined by new-onset deltoid weakness on MMT.

RESULTS

We identified 242 patients with a mean age of 62.4 years and mean follow-up of 27.9 months. Forty-two (17.4%) experienced postoperative C5 palsy. On univariable analysis, significant predictors of postoperative C5 palsy were mean C4/5 foraminal diameter (2.8 vs. 3.2 mm; p<.001), anterior projection of the C5 superior articular process (4.12 vs. 3.70 mm; p=.04), cord float back (0.35 vs. 0.28 cm; p=.02), undergoing laminectomy of the C5 (p=.02) or C4 and C5 levels (p=.02), and undergoing instrumented fusion extending one level above and below the C4/5 level. Foraminotomy of the C4/5 level was not predictive of postoperative palsy. On multivariable analysis mean C4/5 foraminal diameter (odds ratio=0.38 per mm; p<.01) predicted C5 palsy; cord float back at the C4/5 level was not predictive of C5 palsy.

CONCLUSIONS

Spinal cord float back was not an independent predictor of C5 palsy on multivariable analysis. Only smaller foraminal diameter was independently predictive of postoperative C5 palsy. This suggests that chronic preoperative compression of the C5 roots, not postdecompression float back may be the biggest contributor to the etiology of postoperative C5 palsy.

Intraoperative Shoulder Traction as Cause of C5 Palsy: Magnetic Resonance Imaging Study

OBJECTIVE

During surgery, shoulder traction is often used for better fluoroscopic imaging of the lower cervical spine. Traction on the C5 root has been implicated as a potential cause of C5 palsy after cervical spine surgery. Using magnetic resonance imaging, this study was undertaken to determine the impact of upper extremity traction on the C5 root orientation.

METHODS

In this study, 5 subjects underwent coronal magnetic resonance imaging of the cervical spine and left brachial plexus. Using a wrist restraint, sequential traction on the left arm with 10, 20, and 30 lb. was applied. Measurements of the angle between the spinal axis and C5 nerve root and the angle between the C5 nerve root and the upper trunk of the brachial plexus were obtained. The measurements were taken by a trained neuroradiologist and analyzed for significance.

RESULTS

The angle between the C5 nerve root and the vertical spinal axis remained within 3 and 4 degrees of the mean and was not found to be associated with increased traction weight (P = 0.753). The angle between the C5 root and the upper trunk increased with increasing weight and was found to be statistically significant (P = 0.003).

CONCLUSIONS

While the cause of C5 palsy is likely multifactorial, this study provides evidence that, in the awake volunteer, upper extremity traction leads to C5 root and upper trunk tension. These results suggest that shoulder traction in the anesthetized patient could lead to tension of the C5 nerve root and subsequent injury and palsy.

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.

Factors Associated With C5 Palsy Following Cervical Spine Surgery: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

C5 palsy (C5P) is a not uncommon and disabling postoperative complication with a reported incidence varying between 0% and 30%. Among others, one explanation for its occurrence includes foraminal nerve root tethering. Although different risk factors have been reported, controversy about its causation and prevention persists. Inconsistent study findings contribute to the persistent ambiguity leading to an assumption of a multifactorial nature of the underlying C5P pathophysiology. Here, we report the results of a systematic review on C5P with narrow inclusion criteria in the hope of elucidating risk factors for C5P due to a common pathophysiological mechanism.

METHODS

Electronic databases from inception to March 9, 2019 and references of articles were searched. Narrow inclusion criteria were applied to identify studies investigating demographic, clinical, surgical, and radiographic factors associated with postoperative C5P.

RESULTS

Sixteen studies were included after initial screening of 122 studies. Eighty-four risk factors were analyzed; 27 in ≥2 studies and 57 in single studies. The pooled prevalence of C5P was 6.0% (range: 4.2%-24.1%) with no consistent evidence that C5P was associated with demographic, clinical, or specific surgical factors. Of the radiographic factors assessed, specifically decreased foraminal diameter and preoperative cord rotation were identified as risk factors for C5P.

CONCLUSION

Although risk factors for C5P have been reported, ambiguity remains due to potentially multifactorial pathophysiology and study heterogeneity. We found foraminal diameter and cord rotation to be associated with postoperative C5P occurrence in our meta-analysis. These findings support the notion that factors contributing to, and acting synergistically with foraminal stenosis increase the risk of postoperative C5P.

Epidemiology of C5 Palsy after Cervical Spine Surgery: A 21-Center Study

Objective

C5 palsy is a severe complication after cervical spine surgery, the pathophysiology of which remains unclear. This multicenter study investigated the incidence of C5 palsy following cervical spine surgery in Korea.

Methods

We conducted a retrospective multicenter study involving 21 centers from the Korean Cervical Spine Study Group. The inclusion criteria were cervical spine surgery patients between 2012 and 2016, excluding cases of neck surgery. In patients with C5 palsy, the operative methods, disease category, onset time of C5 palsy, recovery time, C5 manual muscle testing (MMT) grade, and post-C5 palsy management were analyzed.

Results

We collected 15,097 cervical spine surgery cases from 21 centers. C5 palsy occurred in 88 cases (0.58%). C5 palsy was more common in male patients (p=0.019) and after posterior approach procedures (p<0.001). C5 palsy usually occurred within 3 days after surgery (77 of 88, 87.5%) and most C5 palsy patients recovered within 6 months (51 of 88, 57.95%). Thirty C5 palsy patients (34.09%) had motor weakness, with an MMT grade≤2. Only four C5 palsy patients (4.5%) did not recover during follow-up. Posterior cervical foraminotomy was performed in 7 cases (7.95%), and steroids were used in 56 cases (63.63%). Twenty-six cases (29.55%) underwent close observation only.

Conclusion

The overall incidence of C5 palsy was relatively low (0.58%). C5 palsy was more common after posterior cervical surgery and in male patients. C5 palsy usually developed within 3 days after surgery, and more than half of patients with C5 palsy recovered within 6 months.

Incidence and Outcomes of C5 Palsy and Axial Pain After Open-Door Laminoplasty or Laminectomy and Fusion: A Meta-Analysis

OBJECTIVE

C5 palsy and axial pain are significant factors affecting the quality of life after posterior cervical surgery; however, there has been no clear and supportive conclusion on which method is more suitable in a certain case. As a result, we compare the clinical outcomes, complication rates, and anatomical changes between open-door laminoplasty (ODL) and laminectomy and fusion (LF) for cervical spondylotic myelopathy. This is a systematic literature review and meta-analysis.

METHODS

A comprehensive literature search was conducted using PubMed, Embase, and the Cochrane library. The following outcomes were extracted and analyzed: the cases of C5 palsy and axial pain patients, Japanese Orthopaedic Association, range of motion (ROM), and cervical curvature. Data analysis was conducted with RevMan 5.3. The I² statistics were used to evaluate heterogeneity.

RESULTS

A total of 9 studies were included in the final analysis, all of which were prospective or retrospective cohort studies. The pooled data showed that the incidences of C5 palsy and axial pain in LF were higher than those in ODL. The study indicated that there was no significant difference in pre- and postoperative Japanese Orthopaedic Association scores, preoperative cervical ROM, pre- and postoperative cervical curvature between the 2 groups, but there was significant difference in ROM after operation. These results indicate that ODL was superior to LF in maintaining cervical ROM.

CONCLUSIONS

Our results demonstrate that the lower incidence of C5 palsy and axial pain can be achieved by using ODL compared with LF. However, current data only provide weak support, if any, favoring ODL over for clinical improvement in reduce these 2 complications.

Selective blocking laminoplasty in cervical laminectomy and fusion to prevent postoperative C5 palsy

BACKGROUND CONTEXT

Cervical laminectomy and fusion (CLF) is a common surgical option for multilevel cord compression. Postoperative C5 palsy occurrence after CLF has been a vexing problem for spine physicians. The posterior shift of the cord following laminectomy has been implicated as a major factor for postoperative C5 palsy, but attempts by spine surgeons to mitigate excessive shift while providing sufficient decompression have not been well reported.

PURPOSE

To compare the incidence of postoperative C5 palsy after performing selective blocking laminoplasty concurrently with CLF to those of conventional CLF.

STUDY DESIGN

A retrospective comparative study of prospectively collected data.

PATIENT SAMPLE

Of 116 cervical myelopathy patients with degenerative cervical myelopathy, ossification of the posterior longitudinal ligament, and multilevel disc herniation, 93 patients (69 in group A [CLF group] and 24 in group B [selective blocking laminoplasty with CLF, CLF-S group]) were included in the study.

OUTCOME MEASURES

The primary outcome measure was the occurrence of postoperative C5 palsy. Secondary end points included (1) clinical outcomes based on pain intensity, neck disability index (NDI), Japanese Orthopaedic Association (JOA) score, (2) radiologic outcomes including cervical alignment and fusion rate at 1 year and hardware complications, and (3) perioperative data (hospital stay, blood loss, and operative times).

METHODS

We compared the occurrence of postoperative C5 palsy, as well as clinical, radiologic, and surgical outcomes, between the two groups at 1-year follow-up.

RESULTS

The patients in both groups were statistically similar between the groups with respect to demographic characteristics such as age, sex, smoking status, body mass index, preoperative pathology, surgical segments, and the degree of the cervical lordosis. Postoperative C5 palsy developed in 9 of 61 patients (14%) in group A and in 0 of 24 patients (0%) in group B (CLF-S group) (p=.03). Postoperative neck pain, NDI, and JOA improvement were not significantly different between the two groups (p=.93, 0.90, and 0.79, respectively). Perioperative data did not differ significantly between the two groups.

CONCLUSIONS

This study showed that performing selective blocking laminoplasty might lead to reducing the incidence of postoperative C5 palsy in CLF surgery.

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.

Differences in Cross-Sectional Intervertebral Foraminal Area From C3 to C7

STUDY DESIGN

Anatomical comparative study.

OBJECTIVES

Few studies have evaluated foraminal areas in the cervical spine without degenerative changes. The purpose of this study was to determine and compare the mean cross-sectional foraminal areas between the C3/4, C4/5, C5/6, and C6/7 levels while also analyzing specimens for differences between sexes and races.

METHODS

We performed an anatomic study of the intervertebral foramen at 4 levels (C3/4, C4/5, C5/6, C6/7) in 100 skeletally mature osseous specimens. Specimens were selected to obtain equal number of African American and Caucasian males and females (n = 25/group) aged 20 to 40 years at time of death. Foramina were photographed bilaterally with and without a silicone rubber disc. The maximal vertical height and mid-sagittal width of each foramen were digitally measured and the areas were calculated using an ellipse as a model.

RESULTS

The average age at death for all specimens was 30 ± 6 years. The mean cross-sectional area of the C4/5 foramen was significantly smaller compared with the C5/6 (P < .001). C5/6 was significantly narrower than C6/7 (P < .001) foramen with and without disc augmentation. C3/4 was not significantly different from more caudal levels. There was no difference between male and female specimens, while African Americans had smaller foraminal sizes than Caucasians.

CONCLUSIONS

This study provides the largest anatomical reference of the cervical intervertebral foramen. In a mature spine without facet joint hypertrophy or osteophytic changes, the C4/5 foramen was narrower than C5/6, which was narrower than C6/7. Understanding the relative foraminal areas in the nonpathological cervical spine is crucial to understanding degenerative changes as well as the anatomical changes in pathologies that affect the intervertebral foramen.

Analysis of C5 palsy in cervical myelopathy with massive anterior compression following laminoplasty

BACKGROUND

Little data is available about comparison of the incidence and clinical characteristics of the C5 palsy between patients of cervical myelopathy with occupying ratio greater than 50% and those with occupying ratio less than 50% following laminoplasty.

METHODS

One-hundred eighteen patients with cervical myelopathy who underwent open door laminoplasty were reviewed in this study. The patients were divided into two groups: group A comprising 55 patients with an anterior occupying ratio greater than 50% and group B comprising 63 patients with an anterior occupying less than 50%. Clinical and radiological outcomes were assessed between two groups.

RESULTS

No statistically difference was found in preoperative Japanese Orthopedic Association (JOA) score of both groups (10.7 ± 1.7 in group A vs 10.9 ± 1.1 in group B, P > 0.05). Improvements in postoperative JOA score were achieved, and there was a statistical difference (14.0 ± 1.4 in group A vs 14.8 ± 0.9 in group B, P < 0.05). Group A had a lower rate of recovery than group B (P < 0.05). Totally, 12 of 118 (10.2%) patients developed the C5 palsy postoperatively. C5 palsy occurred in 3 of 63 patients in the group B compared with 9 of 55 in the group A. Statistically significant difference was found in the incidence of C5 palsy between the two groups (P < 0.05). Furthermore, patients in group A required significantly longer recovery periods than group B. Both preoperative and postoperative MRI presented more levels of T2 high-signal lesion in group A than group B. The degree of posterior shift of the cord after posterior decompression in group A was less than group B (P < 0.05).

CONCLUSIONS

Patients with a high degree of anterior compression have higher risk of C5 palsy than those with a relative low degree of anterior compression.

Why Does C5 Palsy Occur After Prophylactic Bilateral C4-5 Foraminotomy in Open-Door Cervical Laminoplasty? A Risk Factor Analysis

STUDY DESIGN

Retrospective study.

OBJECTIVES

To evaluate the efficacy of bilateral C4-5 foraminotomy in preventing occurrence of postoperative C5 palsy and to identify possible risk factors for its development.

METHODS

A total of 70 consecutive patients who underwent open-door laminoplasty with bilateral C4-5 foraminotomy were included. Clinical, radiographic, and operative data was reviewed. Development of postoperative C5 palsy was analyzed.

RESULTS

A total of 54 males and 16 females were reviewed. Mean age was 56 years (range, 30-86 years). The primary pathology was spondylosis in 76% of cases and ossified posterior longitudinal ligament in 21%. Radiographic evidence of C4-5 foraminal stenosis was seen in 81% of the patients. The mean duration of preoperative symptoms was 7 ± 19 months. Four (5.7%) out of 70 patients developed C5 palsy after open-door laminoplasty with bilateral C4-5 foraminotomy. Multivariate analysis showed that a long duration of preoperative symptoms (>12 months) and the presence of preoperative C4-5 T2-MRI cord signal change were statistically significant risk factors for the development of C5 palsy even after bilateral C4-5 foraminotomy in open-door laminoplasty (P < .0001 and P = .036, respectively).

CONCLUSIONS

Prophylactic bilateral C4-5 foraminotomies do not completely eliminate the occurrence of C5 palsy. Prolonged duration of symptoms and presence of preoperative T2-MRI cord signal change increase the risk for developing postoperative C5 palsy despite foraminotomy.