Cord Shift Research Articles

Shoulder Traction as a Possible Risk Factor for C5 Palsy in Anterior Cervical Surgery: A Cadaveric Study.

Background and Objectives: Many risk factors for postoperative C5 palsy (PC5P) have been reported regarding a "cord shift" after a posterior approach. However, there are few reports about shoulder traction as a possible risk factor of anterior cervical surgery. Therefore, we assessed the stretched nerve roots when shoulder traction was applied on cadavers. Materials and Methods: Eight cadavers were employed in this study, available based on age and the presence of foramen stenosis. After dissecting the sternocleidomastoid muscle of the cadaver, the shoulder joint was pulled with a force of 2, 5, 8, 10, 15, and 20 kg. Then, the stretched length of the fifth nerve root was measured in the extra-foraminal zone. In addition, the same measurement was performed after cutting the carotid artery to accurately identify the nerve root's origin. After an additional dissection was performed so that the superior trunk of the brachial plexus could be seen, the stretched length of the fifth and sixth nerve roots was measured again. Results: Throughout the entire experiment, the fifth nerve root stretched out for an average of 1.94 mm at 8 kg and an average of 5.03 mm at a maximum force of 20 kg. In three experiments, the elongated lengths of the C5 nerve root at 8 kg and 20 kg were 1.69/4.38 mm, 2.13/5.00 mm, and 0.75/5.31 mm, respectively, and in the third experiment, the elongated length of the C6 nerve root was 1.88/5.44 mm. Conclusions: Although this was a cadaveric experiment, it suggests that shoulder traction could be the risk factors for PC5P after anterior cervical surgery. In addition, for patients with foraminal stenosis and central stenosis, the risk would be higher. Therefore, the surgeon should be aware of this, and the patient would need sufficient explanation.

Using Finite Element Models to Assess Spinal Cord Biomechanics after Cervical Laminoplasty for Degenerative Cervical Myelopathy.

Cervical laminoplasty is an established motion-preserving procedure for degenerative cervical myelopathy (DCM). However, patients with pre-existing cervical kyphosis often experience inferior outcomes compared to those with straight or lordotic spines. Limited dorsal spinal cord shift in kyphotic spines post-decompression and increased spinal cord tension may contribute to poor neurological recovery and spinal cord injury. This study aims to quantify the biomechanical impact of cervical sagittal alignment on spinal cord stress and strain post-laminoplasty using a validated 3D finite element model of the C2-T1 spine. Three models were created based on the C2-C7 Cobb angle: lordosis (20 degrees), straight (0 degrees), and kyphosis (-9 degrees). Open-door laminoplasty was simulated at C4, C5, and C6 levels, followed by physiological neck flexion and extension. The results showed that spinal cord stress and strain were highest in kyphotic curvature compared to straight and lordotic curvatures across all cervical segments, despite similar segmental ROM. In flexion, kyphotic spines exhibited 103.3% higher stress and 128.9% higher strain than lordotic spines and 16.7% higher stress and 26.8% higher strain than straight spines. In extension, kyphotic spines showed 135.4% higher stress and 241.7% higher strain than lordotic spines and 21.5% higher stress and 43.2% higher strain than straight spines. The study shows that cervical kyphosis leads to increased spinal cord stress and strain post-laminoplasty, underscoring the need to address sagittal alignment in addition to decompression for optimal patient outcomes.

Decompressive Cervical Laminectomy and Lateral Mass Screw-Rod Fusion for Multisegmental Cervical Spondylotic Myelopathy with Flexible Sagittal Cervical Alignment

Background data: Posterior cervical laminectomy and lateral mass screw-rod fusion techniques were classically recommended in flexible sagittal cervical alignment relying on indirect decompression via posterior cord shift. Purpose: This study aims to investigate the efficacy of posterior cervical laminectomy with lateral mass screw-rod fixation for treating multisegmental cervical spondylotic myelopathy with flexible sagittal cervical alignment. Study Design: Prospective clinical cohort study. Patients and Methods: In total, 38 patients with clinically symptomatic M-CSM with instability and/or flexible kyphosis were admitted to our Zagazig university hospitals for posterior cervical laminectomy and lateral mass screw-rod fusion (long-segment instrumented fusion ≥3 segments) and completed the 24-month follow-up period between April 2014 and June 2018 and the last follow-up visit took place in October 2020. Patients were categorized into lordotic, straight, and kyphotic groups according to the shape of the cervical spine curve on a neutral lateral X-ray view. Results: A total of 266 lateral mass screws were inserted in 134 levels in 38 patients (3 levels in 20 patients, 4 levels in 16 patients, and 5 levels in 2 patients), all the patients had a good fusion, and the cervical spine was stable, based on the absence of hardware failure or subsidence. All 38 patients (100%) gained more lordosis with a variable degree according to the preoperative cervical sagittal alignment. The mean percentage of neck pain improvement according to the Visual Analogue Scale (VAS) for the lordotic group was 69.1%, for the straight group was 43.8%, and for the kyphotic group was 15.8%. The mean percentage of neurological function improvement (JOA score) for the lordotic group was 83.17%, for the straight group was 43%, and for the kyphotic group was 17%. The mean percentage of disability improvement (NDI score) for the lordotic group was 47.66%, for the straight group was 24.5%, and for the kyphotic group was 16.66%. Conclusion: Decompressive cervical spine laminectomy with lateral mass screw stabilization is effective in treating multisegmental cervical spondylotic myelopathy with flexible sagittal cervical alignment. (2022ESJ259)

Double Dome Laminoplasty: A Novel Technique for C2 Decompression.

ObjectiveTo introduce a new surgical technique - double dome laminoplasty for decompression of the entire C2 lamina and preservation of an extensor muscle insertion. MethodsEleven consecutive cervical myelopathy patients due to ossification of the posterior longitudinal ligament involving the Axis (C2) area were contained at this study. Direct decompression was evaluated as an increasing rate in space available cord (%) and posterior cord shift (mm) at C2 level. The Japanese Orthopaedic Association (JOA) score, visual analogue scale, and C2–7 Cobb angle in a neutral lateral x-ray were analyzed. ResultsThe mean increase in space available for spinal cord at the C2 level, average posterior cord shift, and JOA recovery rate were 69.7%, 5.3±0.15 mm, and 58.0%, respectively. Cervical lordotic angle was maintained in all patients. One patient reported neck pain (visual analogue scale 6) postoperatively. No specific complications such as C2 laminar fracture or insufficient decompression were observed. ConclusionWe recommend double dome laminoplasty for treating patients with cervical myelopathy involving the C2 area to avoid C2 laminectomy, reduce postoperative neck pain, and maintain lordotic cervical spine alignment.

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

Background ContextC5 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. PurposeTo 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 DesignAnatomical study of cervical dissection of 13 embalmed cadavers. MethodsThirteen 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. ResultsWe 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. ConclusionThe 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 SignificanceThis 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.

Surgical Outcomes of Selective Laminectomy for Patients With Cervical Kyphosis: A Retrospective Study of 379 Cases.

A retrospective study. This study aimed to investigate the impact of cervical kyphosis on patients with cervical spondylotic myelopathy (CSM) following selective laminectomy (SL) regarding posterior spinal cord shift (PSS), and a number of SLs. We evaluated 379 patients with CSM after SL. The patients with kyphosis (group K) were compared with those without kyphosis (group L). Moreover, groups K and L were divided into subgroups KS and KL (SLs ≤ 2) and LS and LL (SLs ≥ 3), respectively, and analyzed. Receiver operating characteristic (ROC) curve analysis was performed to determine the cut-off value of the C2-C7 angle for satisfactory surgical outcomes, which was defined as a Japanese Orthopaedic Association (JOA) recovery rate of ≥50% in group KS. The average PSS (mm) in group K was smaller than that in group L (.8 vs 1.4; P < .01), but the JOA recovery rate was comparable between the 2 groups. Meanwhile, the mean PSS and JOA recovery rate (%) in group KS was lower than those in group KL, respectively (.3 vs 1.0; P < .01, 35.1 vs 52.3; P = .047). Moreover, the average PSS of group KS (.6) was smaller than those of other subgroups ( < .01). In addition, the ROC curve analysis showed that the C2-C7 angle of -14.5° could predict satisfactory surgical outcomes in group KS. Selective laminectomy is not contraindicated for patients with kyphosis, but a larger number of SLs may be indicated for the patients with C2-C7 angles of ≤ -14.5°.

Relationship of Change in Cervical Curvature after Laminectomy with Lateral Mass Screw Fixation to Spinal Cord Shift and Clinical Efficacy

Although laminectomy with lateral mass screw fixation (LCSF) is an effective surgical treatment for cervical spondylotic myelopathy (CSM), loss of cervical curvature may result. This study aimed to investigate the effect of cervical curvature on spinal cord drift distance and clinical efficacy. We retrospectively analyzed 78 consecutive CSM patients with normal cervical curvature who underwent LCSF. Cervical curvature was measured according to Borden's method 6 months after surgery. Study patients were divided into two groups: group A, reduced cervical curvature (cervical lordosis depth 0-7mm; n = 42); and group B, normal cervical curvature (cervical lordosis depth 7-17mm; n = 36). Spinal cord drift distance, laminectomy width, neurologic functional recovery, axial symptom (AS) severity, and incidence of C5 palsy were measured and compared. Cervical lordosis depth was 5.1 ± 1.2 mm in group A and 12.3 ± 2.4 mm in group B (p < 0.05). Laminectomy width was 21.5 ± 2.6 mm in group A and 21.9 ± 2.8 mm in group B (p > 0.05). Spinal cord drift distance was significantly shorter in group A (1.9 ± 0.4 vs. 2.6 ± 0.7 mm; p < 0.05). The Japanese Orthopaedic Association (JOA) score significantly increased after surgery in both groups (p < 0.05). Neurologic recovery rate did not differ between the two groups (61.5 vs. 62.7%; p > 0.05). AS severity was significantly higher in group A (p < 0.05). C5 palsy occurred in three group A patients (7.1%) and four group B patients (11.1%), but the difference was not significant (p > 0.05). After LCSF, 53.8% of the patients developed loss of cervical curvature. A smaller cervical curvature resulted in a shorter spinal cord drift distance. Loss of cervical curvature was related to AS severity but not improvement of neurologic function or incidence of C5 palsy.

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

Basic in vivo research. The aim of this study was to establish an animal model that is appropriate for analyzing the mechanisms of C5 palsy (C5P) and to clarify the structural and functional alterations of cervical roots following posterior decompression. Although C5P is one of the major complications of cervical surgery, the exact pathogenesis of C5P remains unclear partly because of the lack of an appropriate animal model. Tethering of the cervical roots due to posterior cord shift following posterior decompression is thought to be one of the possible factors that cause C5P. Twenty-eight Sprague-Dawley rats were divided into Group L (cervical laminectomy, N = 18) or Group S (sham surgery, N = 10) and examined up to postoperative day 14 (PO14). Posterior cord shift and the length of the anterior rootlets were quantified by computed tomography-myelogram images. Motor evoked potential (MEP) of the deltoid (C5, 6 innervated) and triceps brachii (C7-T1 innervated), mechanical allodynia, and grip strength of the forepaw (C7-T1 regulated) were measured. All anterior rootlets were elongated as the cord gradually shifted posteriorly postoperatively. The elongation rate of the C6 anterior rootlets was the highest (142% at PO14). The MEP latency of the deltoid was significantly delayed throughout all postoperative time points. However, significant delay in the latency of the triceps brachii was observed only on postoperative day 10. The withdrawal threshold of the forepaw did not change; grip strength of the forelimb decreased at PO14. This model was thought to be appropriate for analyzing the pathogenesis of C5P since our findings were comparable to the clinical course of C5P subsequent to posterior cervical decompression. Although a future study for clarifying histological and molecular alterations will be needed, tethering of the anterior rootlets due to posterior cord shift was suggested to be a probable mechanism causing C5P.Level of Evidence: 5.

What have we learned from C5 palsy – A short communication

A study group on C5 palsy retrospectively reviewed 1001 cervical operations at their institutions in order to understand the incidence, prognosticators, pathogenesis, and outcome of C5 palsy after cervical operations. Three studies are summarized. C5 palsy was higher after posterior versus anterior operations. C4-C5 foraminotomy and age were the strongest predictors of C5 palsy after posterior surgeries and anterior cervical decompression-fusion, respectively. Among patients undergoing C4-C5 posterior laminoforaminotomy with instrumented fusion, cord shift on postoperative imaging was thought to be implicated in the pathogenesis of C5 palsy. Among affected patients, 81.4% recovered. Median time to resolution of C5 palsy was between 6 months to 1 year.

Neurological Disturbance of the Upper Extremities After Cervical Laminoplasty: A Morphological Assessment Focused on the Intervertebral Foramen.

A retrospective study. The aim of this study was to explore the relationship between postoperative neurological disturbance of the upper extremities (NDUE) after cervical laminoplasty and intervertebral foraminal stenosis. The relationship between foraminal stenosis and neurological disturbance in the C5 segment (C5 palsy) has been reported, but the relationship at other levels has not been examined before. We evaluated foraminal stenosis morphologically using three-dimensional computed tomography (3D-CT), alongside other risk factors for NDUE. We retrospectively reviewed patients treated by open-door laminoplasty at the authors' institution between January and June 2016. NDUE was defined as postoperative motor deterioration and/or newly emerged sensory disturbance within 2 weeks of surgery. Radiological measurements were performed in bilateral intervertebral foramina from C5 to C8, using 3D-CT. Investigation using magnetic resonance imaging (MRI) was also performed. Thirty-one patients were reviewed, and 10 (32.3%) developed NDUE. Nineteen NDUE were observed: seven were in the C5 segment, five in the C6 segment, three in the C7 segment, and four in the C8 segment. Four patients (40%) had NDUE from multiple segments. The mean width of the foramen was 2.60 ± 1.26 mm and 3.66 ± 1.66 mm (P = 0.007), and cross-sectional area was 32.8 ± 10.8 mm and 41.6 ± 12.4 mm (P = 0.003), in symptomatic (n = 19) and nonsymptomatic (n = 187) foramina, respectively. The mean transverse diameter of bony spurs and the maximum shift of the spinal cord on MRI was significantly larger in the NDUE group. The odds ratio of having a foraminal cross-sectional area under 28.0 mm in combination with a maximum spinal shift over 3.10 mm was 14.6 (P < 0.001). Stenosis of the intervertebral foramen could be a risk factor for NDUE after cervical laminoplasty, and could be aggravated by excessive posterior spinal cord shift. 3.

A New Indicator Predicting the Degree of Cord Shift After Posterior Decompression of Cervical Ossification of the Posterior Longitudinal Ligament Extended to the C2 Level and Its Clinical Usefulness.

To evaluate the usefulness of the rostral line (R-line) as a new index for determining the degree of C2 lamina decompression in the context of ossification of the posterior longitudinal ligament (OPLL) extending to the C2 level. The R-line was devised based on the mechanism by which the cord is shifted backward following cervical posterior decompression. According to their R-line status, 36 patients with cervical OPLL extending to the C2 level were divided into two groups of R-line (+) and R-line (?) cases, where the R-line touched the upper half of the posterior C2 lamina in the R-line (+) group and the inferior half of the posterior C2 lamina in the R-line (?) group, respectively. Eighteen patients were classified as R-line (+) and 18 patients were classified as R-line (?). Total laminectomy of the C2 lamina was more common in the R-line (+) group, while dome-shape C2 laminectomy was more common in the R-line (?) group. All patients requiring reoperation were included in the R-line (+) group. Only the operation type showed a statistically significant difference according to the need for reoperation in the R-line (+) group; specifically, all patients who underwent reoperation in the R-line (+) group had dome-shape C2 laminectomy. It was determined that the risk factor for reoperation in the R-line (+) group was a history of dome-shape C2 laminectomy. If the R-line touches the upper half of the posterior C2 lamina, total decompression of the C2 lamina should be performed.

Вплив кріоконсервованих ядровмісних клітин кордової крові та інверсії світлового режиму на стан еритроцитів крові щурів різного віку

Вплив кріоконсервованих ядровмісних клітин кордової крові та інверсії світлового режиму на стан еритроцитів крові щурів різного віку

Comparison of microendoscopic selective laminectomy versus conventional laminoplasty in patients with degenerative cervcical myelopathy: a minimum 2-year follow-up study

BackgroundAlthough microendoscopic partial laminectomy for patients with degenerative cervical myelopathy (DCM) has been reported and demonstrated good results, a detailed comparison of its mid-term surgical results with those of laminoplasty (LP) has not been reported. The aim of this study was to compare the surgical outcomes, complications, and imaging parameters of cervical microendoscopic interlaminar decompression (CMID) via a midline approach versus conventional laminoplasty, with a minimum follow-up period of 2 years.MethodsTwo hundred and fifty-four patients who underwent either LP or CMID for DCM between May 2008 and April 2015 were enrolled. All patients routinely underwent LP (C3–6 or C3–7) before December 2011, whereas CMID was performed at the one or two affected level(s) only in patients with single- or two-level spinal cord compression after 2012.Surgical procedure (CMID): For single-level patients (e.g., C5–6), partial laminectomy of C5 and C6 was performed under a microendoscope. For two-level patients (e.g., C5–6-7), decompression was completed by performing a C6 laminectomy.We compared surgical outcomes and radiographic parameters between the CMID and LP groups.ResultsOf the 232 patients followed up for > 2 years, 87 patients with single- or two-level spinal cord compression, 46 that underwent CMID, and 41 that underwent LP were identified. There were no differences in the baseline demographic data of the patients between the groups. CMID showed better outcomes in terms of postoperative axial pain and quality of life, although both procedures showed good neurological improvement. Two and one patient complained of C5 palsy and hematoma, respectively, only in the LP group. The postoperative range of motion was worse and the degree of postoperative posterior spinal cord shift was larger in the LP group.ConclusionSelective decompression by CMID demonstrated surgical outcomes equivalent to those of conventional LP, which raises a question regarding the requirement of extensive posterior spinal cord shift in such patients. Although the indications of CMID are limited and comparison with anterior surgery is mandatory, it can be a minimally invasive procedure for DCM.

Accuracy of Bony Gutter Placement in Cervical Laminoplasty Assisted by 3-D Print Modeling, and Associations with Posterior Spinal Cord Shift and Radiculopathy.

Introduction We evaluated the positioning of the bony gutter (PBG) in cervical laminoplasty aided by three-dimensional (3-D) printed models, and assessed associations between PBG accuracy¸ posterior shift of the spinal cord (PSSC), and clinical results. Methods Of 35 patients who underwent cervical laminoplasty for cervical myelopathy between January 2013 and September 2015, 20 were treated using a conventional free-hand technique (Group A). For the other 15 patients (Group B), surgeons also used 3-D printed models to select a PBG on the edge of the medial aspect of the zygapophyseal joint to maximize the angle of the opened lamina (AOL). We measured the PBG and AOL on axial computed tomography images, and the PSSC on midsagittal magnetic resonance imaging obtained before and 7 days after surgery. Clinical outcomes were evaluated by Japanese Orthopaedic Association (JOA) scores and recovery rates, and by the incidence of postoperative radiculopathy. We compared the PBG, AOL, PSSC, and clinical outcomes between the groups. Results The PBG was significantly lower in Group B than in Group A at the C4 left and right sides (P = 0.033, P < 0.0001) and C6 left side (P = 0.004), and the AOL was larger at the C4 right side, C5 left and right sides, C6 left side, and C7 right side (P = 0.040, 0.043, 0.016, 0.016, and 0.027, respectively). Group B had a higher percentage of on-target PBGs at the right sides of C4 and C5 and the left side of C7 (P = 0.005, 0.037, and 0.028), a larger PSSC at C4 and C5 (P = 0.023, 0.008), and a higher incidence of radiculopathy (P = 0.026). Groups A and B did not differ significantly in JOA score or recovery rate. Conclusions Three-dimensional modeling improved PBG accuracy. However, maximizing the spinal canal increased the PSSC and subsequent radiculopathy.

Differential Analysis of the Spinal Cord Shift After Laminoplasty With Upper Extension to the C2 Segment and Conventional Surgery of the C3-C7 Segments.

A retrospective controlled study. To clarify the differences of spinal cord shift between laminoplasty with extension to the C2 segment and conventional surgery of the C3-C7 segments. For patients of spinal cord compression at C2/C3 or C2, it is difficult to achieve decompression involving only the C3-C7 segments. Therefore, a laminoplasty with upper extension to C2 is needed. Nevertheless, there is not yet a definitive conclusion regarding whether laminoplasty with extension to C2 can achieve a better spinal cord shift than an extension of the C3-C7 segments. Preoperative and final follow-up Japanese Orthopedic Association scores were recorded. MRI T2 patient images before and after surgery were used for data collection. The anterior subarachnoid spaces, spinal cord diameters, posterior subarachnoid spaces, and dural sac diameters were measured. The distance of spinal cord shift in a single plane was represented by the differences in the sum of the anterior subarachnoid spaces and the spinal cord diameters before and after surgery. The overall distances and distances of each segment backward were compared between the C2-C7 group and the C3-C7 group. All planes were also classified as segments with compression or noncompression, and the differences in backward shift were compared. There were no significant differences in Japanese Orthopedic Association score between the C2-C7 and C3-C7 groups at final follow-up and no significant differences in the overall backward shift between the 2 groups. The spinal cord shift of C1, C2, and C2/C3 segments and the segment of the largest shift distance were significantly different between the 2 groups; the spinal cord shift of the segments under compression was larger than that of noncompression. Surgery with upper extension to the C2 segment did not increase the overall spinal cord shift; instead, a better effect was achieved by the effective decompression of local compressed segments, thus obtaining an effective expansion and shift of the spinal cord. Level II.

Surgical Outcomes After Anterior Controllable Antedisplacement and Fusion Compared with Single Open-Door Laminoplasty: Preliminary Analysis of Postoperative Changes of Spinal Cord Displacements on T2-Weighted Magnetic Resonance Imaging

This retrospective cohort study aimed to investigate the change of spinal cord displacements and the occurrence of C5 palsy between anterior controllable antedisplacement and fusion (ACAF) (group A) and single open-door laminoplasty (group L). From January 2016 to December 2017, a total of 80 patients with cervical ossification of the posterior longitudinal ligament (OPLL) were enrolled. All patients underwent computed tomography and magnetic resonance imaging. The types and extent of OPLL, spinal cord rotation, deviation angle, and distance between the vertebral arteries line and spinal cord (DVS) were measured. Patients with postoperative C5 palsy were recorded. Neurologic function was evaluated by Japanese Orthopaedic Association (JOA) score. Three days after surgery, patients in group A had better recovery (6.7° ± 2.4°) of spinal cord rotation than group L (3.1° ± 0.8°; P < 0.05). Deviation angle showed similar changes to spinal cord rotation. At the final follow-up, patients in group A had decreased DVS (11.0 ± 0.7 mm), whereas patients in group L had increased DVS (15.1 ± 0.8 mm) compared with preoperation (P < 0.05). Five patients (1in group A and 4 in group L) developed postoperative C5 palsy (P > 0.05). Patients in group A had a higher JOA score at the final follow-up than those in group L (P < 0.05). ACAF could achieve in situ decompression in terms of spinal cord rotation, deviation angle, and spinal cord shift with better clinical outcomes and relatively lower incidence of C5 palsy compared with single open-door laminoplasty.

Analysis of correlative factors of spinal cord posterior displacement after single door laminoplasty

To observe the open angle (OA), cervical curvature angle (CA), preoperative spinal cord compression rate(PSCR), postoperative spinal cord shift (PSCS) in patients with chronic compressive cervical myelopathy undergoing C3-7 single open laminoplasty, and to explore the possible mechanism and influencing factors of postoperative average spinal cord drift, so as to provide objective basis for predicting PSCS. From May 2012 to July 2016, 32 patients with multi-segmental chronic compressive cervical myelopathy who underwent single-door laminoplasty in our department were analyzed retrospectively, including 14 cases of cervical spondylotic myelopathy, 8 cases of developmental cervical spinal stenosis with cervical myelopathy, and 10 cases of ossification of posterior longitudinal ligament. The OA of cervical spine was measured on CT, the CA was measured on X-ray, the PSCR and PSCS were measured on MRI. The patients were divided into two groups according to PSCS(group A>=2.5 mm, group B<2.5 mm). In the group A, there were 11 males and 6 females, with an average age of (56.58±9.80) years old, a mean course of the disease of (23.52±7.86) months; while in group B, there were 6 males and 9 females, with an average age of (58.46±12.53) years old, a mean course of disease of (21.13±7.75) months. The correlation analysis between PSCS and OA, CA and PSCR was performed, and multiple linear analysis of correlated parameters was carried out. The OA in group A was (40.47±9.45) °, in group B was (27.84±5.67) °. The OA in group A was higher than that in group B (P<0.01), and OA was moderately correlated with PSCS (r=0.794, P=0.000). The CA was(11.56± 4.99) ° in group A and(6.64±3.28) ° in group B . The CA in group A was higher than that in group B (P<0.01), and CA was moderately correlated with PSCS (r=0.632, P=0.000). The PSCR was (27.70±2.92) % in group A , was (24.59±2.80) % in group B . The PSCR in group A was higher than that in group B(P<0.01), PSCR was moderately correlated with PSCS(r=0.667, P=0.000). The CA dependent variable was kicked out(P>0.1), and the partial regression coefficients of OA and PSCR were 0.113 and 0.059 respectively. PSCS is the result of OA, CA and PSCR, among which PSCR has the most important influence, OA is the second, CA is the least. PSCS can be predicted by 0.059×OA+0.113×PSCR-2.266 equation, which provides a theoretical basis for preoperative evaluation of spinal cord decompression after surgery.

Analysis of influencing factors the postoperative axial symptoms of cervical single open-door laminoplasty

To explore the influencing factors and possible mechanism of axial symptoms(AS) after C₃-C₇ single open-door laminoplasty in patients with chronic compression cervical myelopathy. The clinical data of 32 patients with multi-segment chronic compression cervical cord disease treated by C₃-C₇ single open-door laminectomy from May 2012 to July 2016 were retrospectively analyzed. Including cervical spondylotic myelopathy of 14 cases, developmental cervical stenosis complicated with cervical myelopathy of 8 cases, ossification of posterior longitudinal ligament(OPLL) of 10 cases. There were 17 males and 15 females, aged from 47 to 82 years old with an average of 57.46 year, the course of disease was 5 to 35 months with an average of 22.4 months. The opening angle(OA), cervical curvature angle(CA), preoperative spinal cord compression rate(PSCR) and postoperative spinal cord shift (PSCS) were recorded. After 2 weeks of surgery, determining whether occurred an AS condition according to the AS assessment criteria, the patients were divided into a axial symptom group and a non-axial symptom group, the general data and imaging parameters of the two groups were compared and the factors that may be postoperative AS were analyzed by binary Logistic regression analysis. At 2 weeks after operation, 13 patients occurred AS. There was no significant difference in gender, age and course of disease between axial symptom group and a non-axial symptom group (P>0.05). In axial symptom group, OA was(36.76±9.35)°, CA was(11.53±4.36)°, PSCR was(27.83±1.72)%, PSCS was (3.17±0.81) mm, while in non-axial symptom group, above items were (33.03±10.52)°, (7.71±4.73)°, (25.16±3.59)%, (2.43±0.95) mm, respectively, there was significant difference in CA, PSCR, PSCS between two groups(P<0.05), and there was no significant difference in OA between two groups(P>0.05). The results of the binary Logistic regression analysis of 3 parameters(OA, PSCR, PSCS) and AS showed OA and PSCR were eliminated in dependent variables, and the partial regression coefficient of PSCR was 0.311, and P=0.031. CA, PSCR, and PSCS are related influencing factors of AS, and PSCS is a high risk factor for AS. C₄,₅ nerve traction caused by posterior spinal movement, postoperative dural self-expansion causes greater traction of the spinal cord, excessive deformation of the cervical spinal cord causes autonomic nerve damage or necrosis that dominates blood vessels may be the pathogenesis of AS, but this is only a theoretical inference, and further improved experiment is necessary to verify it in the future.

Delayed C5 Palsy After Anterior Cervical Decompression Surgery: Preoperative Foraminal Stenosis and Postoperative Spinal Cord Shift Increase the Risk of Palsy

Postoperative C5 palsy is a well-known complication after cervical decompression with either a posterior or an anterior approach. Its cause has been discussed more regarding the posterior approach. The main hypothesis is that postoperative spinal cord shift causes root traction and palsy. However, the pathogenesis in anterior cases has not been fully described. Therefore, the purpose of this study was to clarify the risk factors for C5 palsy in the anterior approach through our C5 palsy cases. A total of 149 surgical patients with an anterior cervical lesion were treated by a specific spinal surgeon under consistent same treatment strategy. Of these patients, 88 who satisfied the evaluation criteria were enrolled. Postoperative C5 palsy was defined as postoperative weakness of the deltoid with or without weakness of the biceps brachii. Risk factors of C5 palsy were extracted from clinical backgrounds, surgical approaches, and radiologic findings from patients with palsy. Four sides of 3 individuals (4.6%) who underwent multiple corpectomy developed C5 palsy. All paralyses became evident several days after the surgery and recovered. Older age, multiple corpectomy, postoperative spinal cord shift, and foraminal stenosis of C4-5 and C5-6 were statistically extracted as causative factor of C5 palsy. In the patients with palsy, distortion of the anterior nerve root as a result of a residual vertebral spur was observed with anterior spinal cord shift after anterior corpectomy. Multiple corpectomy for patients with longer anterior lesions and locally developed kyphosis is related to a larger postoperative cord shift, which can cause the occurrence of C5 palsy. Moreover, C4-5 or C5-6 foraminal stenosis can accelerate tethering of the C5 or C6 nerve root. Older patients undergoing multiple corpectomy are susceptible to these risks of palsy. Appropriate patient selection and sufficient additional foraminotomy should be considered for extensive anterior lesions and locally developed kyphosis to avoid postoperative C5 palsy.

Narrow width of muscle-preserving selective laminectomy demonstrated sufficient surgical outcomes and reduced surgical invasiveness

Sufficient width of laminectomy or laminoplasty is considered a criterion for successful surgical outcomes following posterior cervical decompression. No previous study has focused on surgical outcomes achieved by wide versus narrow decompression. This study examined whether narrow laminectomy width (LW) affected surgical outcomes in cervical compressive myelopathy (CCM). Between 2005 and 2010, we performed muscle-preserving selective laminectomy (SL) with decompression between the bilateral medial margin of the facet joints (wide SL). After 2010, we began to perform narrow SL, in which the LW was no more than 2–3 mm wider than the spinal cord width (SW). Clinical features and radiological findings from 97 CCM patients in whom SL was performed at two consecutive levels, including the C4/5 level, were examined in this study. The relationship between LW and patients’ functional outcomes was analyzed. Mean blood loss was lower in the narrow SL group than in the wide SL group. The length of hospital stay was also shorter in the narrow SL group. The wide SL group showed greater posterior spinal cord shift. The incidence of C5 palsy correlated with LW and LW minus SW (LW-SW). The recovery rate (RR) of Japanese Orthopaedic Association score was comparable between the two groups. The RR was not correlated with LW and LW-SW. Sufficient functional recovery can be achieved by narrow SL, and it offers advantages over wide posterior decompression, including reduced surgical invasiveness and complications. Wide decompression width is not always necessary for CCM patients.