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

Abstract

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.

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

“…Sixteen studies met inclusion criteria for our systematic review. Three studies included patients receiving surgery through the anterior approach, 20,29,38 9 through a posterior approach, 15,30,31,33,39-43 3 through either the anterior or posterior approach analyzed together, 14,28,32 and 1 through the anterior or posterior approach analyzed separately, 44 (Table 1). Eighty-four different risk factors were analyzed, 27 of which were assessed in ≥2 studies and 57 in single studies.…”

“…Many studies have explored C5P mechanisms, and even more have examined its potential risk factors. 14-17,28-43 However, few of these factors have stood up to repeat scrutiny of being independent predictors for C5P occurrence. For example, although initially described in the setting of patients receiving surgery for ossification of the posterior longitudinal ligament (OPLL), 44 this disease has not been found to be causatively associated after further scrutiny.…”

“…For example, although initially described in the setting of patients receiving surgery for ossification of the posterior longitudinal ligament (OPLL), 44 this disease has not been found to be causatively associated after further scrutiny. 31,39,40 Other purported risk factors have included demographic factors (age, sex, smoking, diabetes), clinical factors (preoperative myelopathy, diagnosis and duration of disease, surgical approach), as well as a host of radiological factors (foraminal stenosis, SC magnetic resonance imaging [MRI] signal change, postoperative SC migration, SC rotation, canal stenosis, among others). 14-16,28-31,33-43 Although we are not the first group to suggest such a notion, 44 we propose that C5P is not one distinct clinical entity with one distinct mechanism, but instead a final common clinical pathway that manifests in a similar fashion from different insults to the C5 nerve root.…”

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

“…Another study showed that prophylactic cervical foraminotomy reduced the incidence of C5 palsy compared with the control group (1.7% vs. 7.0%) through a 2-year prospective study, without adversely affecting cervical alignment, stability, hinge site, neurological recovery, and axial pain [16]. However, a recent retrospective study reported that prophylactic bilateral C4/5 foraminotomies did not eliminate the occurrence of C5 palsy [17]. We could not determine how many C5 palsy patients had received prophylactic cervical foraminotomy, but after the onset of C5 palsy, posterior cervical foraminotomy was performed in 7 cases (7.95%).…”

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

“…[11] Some studies had found that presence of intramedullary linear high intensity areas on both preoperative and postoperative T2-weighted MRIs were seen more at the level of paralysis but the association of these observations and the occurrence of C5 palsy were not consistent. [1,12-14]. …”