Risk Factor Analysis for C5 Palsy after Double-Door Laminoplasty for Cervical Spondylotic Myelopathy

Cervical laminoplasty (CL) is one of the surgical methods via the posterior approach for treating patients with multilevel affected cervical myelopathy (CM). The main purpose of CL is to decompress the cervical spinal cord by widening the narrowed spinal canal, combined with preserving the posterior anatomical structures to the degree possible and preserving the widened space stably. During the development and improvement of spine surgeries including CL, various studies on CM have progressed and useful achievements have been obtained: (1) posterior cervical spine fixation systems that can be used in combination with CL simultaneously have been developed; (2) various materials to stably maintain the enlarged spinal canal have been developed; (3) the main influential factors on the surgical results are the inner factors of the patients, such as the patient's age and the disease duration; (4) various surgical methods to preserve the function of the posterior cervical muscles have been tried to avoid postoperative kyphotic changes of the cervical spine; (5) postoperative complications, such as C5 palsy and axial pain, have been examined, and the countermeasures have been tried; (6) K-line on lateral X-ray films has been applied to evaluate the indication of CL in patients with CM due to ossification of the posterior longitudinal ligament (OPLL) preoperatively; and (7) the method and idea of CL have been adapted to surgeries at the thoracic and lumbar spine. However, some issues remain to be resolved, such as the deterioration of neurological findings, especially in patients with continuous or mixed-type OPLL, the postoperative kyphotic-directional alignment change of the cervical spine, C5 palsy, and axial pain.

Section: B Postoperative C5 Palsymentioning

confidence: 99%

Development and Achievement of Cervical Laminoplasty and Related Studies on Cervical Myelopathy

Hirabayashi

Kitagawa

Yamamoto

et al. 2020

“…Concerning the kinds of nerve tissue involved, there are two theories: 1) the segmental spinal cord disorder theory 18,19) and 2) the nerve root injury theory 9,[20][21][22][23][24][25][26][27][28][29][30][31] .…”

Section: Conjectured Causes Of C5 Palsymentioning

confidence: 99%

“…By contrast, in nerve root injury theory, C5 palsy is thought to be caused by mechanical compression and/or the distraction of the anterior rootlet and/or anterior nerve root 9,[20][21][22][23][24][25][26][27][28][29][30][31] . From this theory, the features of C5 palsy can be well explained.…”

Section: Conjectured Causes Of C5 Palsymentioning

confidence: 99%

“…In patients with hypertrophied facet joints due to degenerative changes, these influences are thought to become larger. After decompression, the influence of the stretching and compression of the nerve root near the exit of the foramen is thought to become higher because of the gradual posterior shift of the spinal cord within the spinal canal, that is, the tethering effect 27,28,31) . In addition to this tethering effect within the spinal canal, the lateral displacement of the multifidus muscles due to postoperative swelling and compression of extradural hematoma outside the spinal canal may cause the stretching of the medial branches of the posterior rami.…”

Section: Anatomical Investigation To Reveal the Causes Of C5 Palsymentioning

confidence: 99%

See 1 more Smart Citation

Postoperative C5 Palsy: Conjectured Causes and Effective Countermeasures

Hirabayashi

Kitagawa

Yamamoto

et al. 2019

Postoperative C5 palsy (C5 palsy) is defined as de novo or aggravating muscle weakness mainly at the C5 region with slight or no sensory disturbance after cervical spine surgery. The features of C5 palsy are as follows: 1) one-half of patients are accompanied by sensory disturbance or intolerable pain at the C5 region; 2) 92% of patients have hemilateral palsy; 3) almost all palsy occurs within a week after surgery; 4) the incidence is almost the same between the anterior and posterior approaches to the cervical spine; 5) the prognosis is relatively good even in patients with severe muscle weakness. Even now, the precise causes of C5 palsy have not yet been revealed. From the viewpoint of the kinds of nerve tissue involved, the uncertain causes of C5 palsy are divided into two theories: 1) the segmental spinal cord disorder theory and 2) the nerve root injury theory. In the former, the segmental spinal cord, particularly the anterior horn cells, is thought to be chemically damaged because of preoperative ischemia and/or the aggression of reactive oxygen during postoperative reperfusion. By contrast, in the latter, the anterior rootlet and/or nerve root are believed to be mechanically damaged because of compression force and/or distraction force. In this theory, the features of C5 palsy can be well explained from anatomical viewpoints. Additionally, various countermeasures have been proposed, such as the intermittent relaxation of the tension of the hooks to the multifidus muscles during surgery; prophylactic foraminotomy to decompress C5 nerve root; prevention of excessive posterior shift of the spinal cord, which may cause the tethering effect of the nerve root; and prevention of excessive postoperative lordotic alignment of the cervical spine. These countermeasures have been proved effective, and may support the nerve root injury theory as the main conjectured theory on the causes of C5 palsy.

“…C5 palsy can result from a posterior shift of the spinal cord (PSSC) after laminoplasty 4,6,7) . Baba et al reported a significantly larger PSSC at C4/5 in patients with postoperative C5 palsy compared to those without palsy (odds ratio, 12.066; P = 0.029; 95% confidence interval, 1.295-112.378), indicating that the tethering phenomenon is a likely risk factor for postoperative C5 palsy 8) . On the other hand, Uematsu et al reported a significantly higher incidence of radiculopathy after cervical laminoplasty when the bony gutter was cut on the lateral side of the medial aspect of the zygapophyseal joint 9) .…”

Section: Introductionmentioning

confidence: 99%

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

Kumagai

Wada

Kudo

et al. 2019

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.