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Abstract

Background:

C5 palsy is a serious complication after cervical decompression surgery in which the patient shows a deterioration in power of the deltoid or biceps brachii by at least one grade in the manual muscle test without aggravation of lower extremity function. Although there are several hypotheses regarding the etiology of C5 palsy, the pathogenesis and preventive measures remain unidentified and many other controversies remain.

Objective:

To systematically review the clinical features, risk factors, mechanism, and preventive measures of C5 palsy after posterior cervical decompression surgery.

Materials and methods:

PubMed was searched to identify eligible studies that contained more than 10 cases and focused on C5 palsy. Microsoft Excel was used to analyze the data. Statistical comparisons were made when appropriate.

Results:

Out of 718 papers involving C5 palsy, 28 met the inclusion criteria. The average incidence rate was 7.8% (range, 1.4–23.0%). Risk factors for C5 palsy included age, male gender, ossification of the posterior longitudinal ligament, and stenosis of the C4–C5 intervertebral foramen. C5 palsy occurred from immediately to 2 months after surgery, and recovery time ranged from 48 h to 41 months. Hypotheses for the mechanism of C5 palsy included root involvement and spinal cord impairment. Foraminotomy and intraoperative neuromonitoring were the two main methods used to prevent C5 palsy.

Conclusion:

C5 palsy is a serious complication occurring at the early stage after cervical decompression surgery. Foraminotomy and intraoperative neuromonitoring were the two main methods to prevent C5 palsy. The incidence of C5 palsy is low, but it can place a serious burden on the patients’ quality of life and finances. The risk factors and mechanism of C5 palsy are still controversial. However, under conservative therapy, the prognosis is usually good. Higher quality studies are necessary for drawing more reliable and convincing conclusions about this disease.

Keywords

C5 palsy cervical spine laminectomy laminoplasty systematic review

Introduction

Posterior cervical decompression surgery with laminectomy or laminoplasty is a well-established procedure that has been widely used for the treatment of cervical myelopathy caused by multilevel spondylosis and/or developmental spinal stenosis, or ossification of the posterior longitudinal ligament (OPLL).¹ The advantages of the posterior approach compared with the anterior approach include indirect decompression without destabilizing the disk space, intuitive operation while exposing multiple levels, and less risk of postoperative instability and adjacent level degeneration.^2–4 Studies have reported more satisfactory surgical outcomes using laminoplasty or laminectomy^5–8; however, postoperative problems, such as C5 palsy, axial pain, segmental instability, restriction of neck motion, perineural adhesions, and loss of lordotic curvature, have also been reported.^2–9

First described as a “dissociated motor loss” by Keegan,¹⁰ C5 palsy is a serious potential complication after cervical decompression surgery in which patients show a deterioration in muscle power of the deltoid or biceps brachii by at least one grade in the manual muscle test (MMT) without aggravation of lower extremity function. Such a complication has been reported mainly after posterior cervical surgery, but has also been documented after surgery via the anterior approach.^11,12 Although many studies on C5 palsy after posterior cervical surgery have been published, the results are often inconclusive and even conflicting.^13,14

Here, we provide a systematic review of the current literature and attempt to analyze the conflicting results among studies to better understand the clinical features, influencing factors, and preventive measures of C5 palsy after posterior cervical surgery.

Materials and methods

A literature search was conducted on the PubMed database (http://www.ncbi.nlm.nih.gov/pubmed/) using the keywords “C5 palsy,” “laminectomy,” and “laminoplasty” with the limitations of human subjects and English language. We also included additional articles found by manual search methods from the references of the identified literature that contained relevant supporting information. The search was performed by two independent reviewers.

After excluding identical papers, we selected only peer-reviewed articles for inclusion. The included articles met the following criteria:

Literature published between 1998 and 2014.

Studies that consisted of 10 or more cases and focused on C5 palsy using statistical analysis.

Articles referring to the posterior surgical approach, or both the posterior and anterior approaches.

Studies with one or more of the following criteria were excluded:

Studies without a clear description and analysis of C5 palsy.

Literature pertaining only to the anterior approach.

Animal, cadaver, and biomechanical studies.

Articles with duplicate information. If more than one article was reported by the same authors from the same institution, the most recently reported article with detailed and complete clinical data was included. If an equal number of patients were reported by the same authors, the articles with the most information were selected.

The data extraction was done independently to minimize selection bias and errors. All abstracts that met our search terms were printed and thoroughly studied by two experienced spine surgeons. Different information extracted from the same article was compared and discussed. Discrepancies were resolved by a third reviewer where necessary. A final total of 28 studies were included in this systematic review. The full text of each study was carefully read, and data extraction was done independently by the authors mentioned above. All extracted data were imported into an electronic Microsoft Excel spreadsheet. A meta-analysis was not conducted, because very few studies specializing in C5 palsy were found, and there was too much clinical heterogeneity among studies. Hence, we have chosen to provide a qualitative descriptive analysis instead.

Results

Clinical features

Twenty-eight papers out of the initial 718 identified in PubMed met the inclusion criteria. This gave a total of 5115 cases, with the number of patients enrolled ranging from 19 to 630 in each study and a mean age of 40.25–70 years at the time of surgery. The duration of follow-up was approximately 9 months to 12 years. The incidence of postoperative C5 palsy varied markedly from 1.4% to 23.0%, with an average incidence of 7.8%. C5 palsy often occurred in the early postsurgical stage (from immediately to 2 months after surgery). The recovery time ranged from 48 h to 41 months (Table 1). Most patients experienced palsy of the deltoid muscle in the early postoperative stage, with symptoms subsiding gradually.^15–18 However, a palsy with MMT ≤ 2 was sometimes irreversible,¹⁹ and often decreased patients’ quality of life and put a burden on their financial status by delaying their return to work after surgery.^18,20 The method employed to diagnose C5 palsy was the MMT, which divides the strength of the muscle into six grades from 0 to 5. Twenty-six out of the 28 included studies reported the risk factors for C5 palsy development (see Table 1).

Table 1.

Clinical features of C5 palsy after posterior cervical surgery.

Authors	No. case (male; female)	Average age (year)	Incidence	Disease	Palsy distribution	Onset time —recovery time	Evaluation MMT	Risk factors	FU
Takemitsu et al.³⁶ 2008	73	60.5	14%(10)	Reducible cervical kyphosis; spinal instability; junctional stenosis	Open 6, hinge 4	Day 1 in 4, the rest between 3 and 7 days after surgery—within 10 months in 4.1 has not fully recovered.	The palsy in 5 patients in non-instrumented group was less severe, and the lowest motor power within the group was only grade 3.	Posterior cervical fusion using instrumentation for restoration of lordotic alignment combined with laminoplasty; anterolisthesis of C4	55 mos (12–135 mos)
Chen et al.²⁴ 2007	49	54	18.4%(9)	OPLL	Bilateral in 5; unilateral in 4.	23.5 h—2 within 4–6 months; 7 need full year	Grade 1 in 7; grade 2 in 2.	Increased cervical lordosis and marked OPLL	20 mos
Katsumi et al.²⁵ 2012	FG 141 NFG141	64(35–84); 64(30–92)	1.4%(2); 6.4%(9)	CSM;CSMR;OPLL;CDH	NA	MMT ≤ 2 takes longer, MMT ≥ 3 shorter	Grade 3 and grade 2	Preoperative foraminal stenosis and posterior shifting of the spinal cord after laminoplasty	16 mos;17 mos
Radcliff et al.²⁷ 2014	25(M15; F10)	61	17	multilevel CSM	NA	NA	NA	A wider laminectomy at C5; Increased preoperative spinal canal diameter	≥ 12 mos
Liu et al.³⁷ 2010	91(44, 37)	40.25	21(23%)	CSM	On one side in three patients and both sides in 18 patients	Immediately in two patients, the following day in 16, and 7 days postoperatively in 3—between 4 weeks and 14 months	Less than grade 3 in MMT	cervical curvature index change rate; excessive intraoperative traction and the use of internal fixation	2 years
Fan et al.⁵ 2002	132; 68(131, 69)	59.6 (28–89)	6 (4.5%); 2 (2.9%)	CSM; OPLL; multiple CDH	Unilateral deltoid muscle paralysis in 8	48 h to 1 year	NA	NA	NA
Yanase et al.³³ 2010	153	59.8	9 (5.8%)	cervical myelopathy without radiculopathy	NA	NA	Decreased by 1 grade or more	NA	NA
Nakamae et al.¹⁶ 2012	184 (130, 54)	64 (27–89)	6 (3.3%)	CSM; OPLL	NA	NA	NA	No abnormal findings on transcranial electric MVP monitoring; male gender	NA
Kaneko et al.³² 2006	66 (38, 28)	67 (50–83)	5 (7.6%)	CSM; OPLL	Unilaterally in all five patients	1 to 3 days after surgery—from 3 to 6 months after the onset	MMT < 21	An HIZ area on T2-weighted MRI; cervical myelopathy at the C4–C5 level	1 year
Minoda et al.⁶ 2003	45 (35, 10)	36–80 (mean, 58.2)	4 (8.9%)	CSM; OPLL; CDH	On the right side in 2, left in 1, and both in 1.	Immediately in 2, the following day in 1, and 7 days in 1—4 weeks and 17 months after onset	Less than grade 3 in MMT	OPLL; gutter position and angle of opened lamina	2 year
Tanaka et al.⁴⁰ 2006	62 (47, 15)	64 (32–89)	3 (4.8%)	CSM; OPLL; CDH; CSA	Unilateral (open side in 2; hinge side in 1)	Day 3 in 2 and day 4 in 1—within 6 months	Grade 2	OPLL	14 mos (12–28)
Sasai et al.⁷ 2003	74; 37	63; 63	0; 3 (8.1%)	CSM; OPLL	NA	8 days, 7 days, and 7 days; 18; 8; 10 mos	MMT 2,2,3	Selective foraminotomy	39 mos;39 mos
Komagata et al.³¹ 2004	305 (231, 74)	57 (19–86)	13 (4.3%)	CSM7; OPLL	NA	4 on the day of surgery;5 on the day of surgery and the day after surgery;4 beyond day 5—NA	NA	No specific risk factors	5 year 8 mos (9 mos to 12 year 6 mos)
Kaneyama et al.²⁸ 2010	Open-door LP 73(53/20); double door 73(55/18)	63.3 ± 11.3; 64.9 ± 9.8	7(9.6%);1(1.4%)	CDH,OPLL,CSM	NA	2 in 2,3 in 2,7 in 1, 12 in 1, 13 in 1;3 in1 —the latest is > 821 day	2 in 4;1 in 2;3 in1—2 in 1.	Surgical procedures of open-door and double-door LP; OPLL	>821 days
Chiba et al.⁸ 2002	208	56 years	15(7.7%)	CSM, OPLL, and CDH	10 in the hinge side; 2 in both; 3 in open side	Average of 4.6 days	4 in grade 4;	Expansive open-door laminoplasty	Minimum follow-up 2 years
Shiozaki et al.¹⁵ 2009	19(15,4)	70(54–89)	2(10.5%)	CSM	Unilateral	Within 24 h—about 3 weeks, within 11 mos	NA	The posterior shift at the C5 level	NA
Nassr et al.²² 2012	630(338,292)	58(19–87)	42(6.7%)	NA	NA	Postoperative to 2 months postoperative—21 weeks(from 1 week to 2 years)	NA	Male	10 mos
Hasegawa et al.²¹ 2007	598		49(5.7%)	CSM; OPLL; CDH; ossification of the ligamentum flavum	NA	Postoperative day 0 in 7 cases, day 1 in 9, days 2–7 in 15, day 7 in 12, and unknown in 6—several weeks to 2 months after surgery	NA	A transient disturbance of the spinal cord following a decompression procedure
Wada et al.⁴ 2001	Subtotal corpectomy 23; laminoplasty 24	52.7 ± 7.8; 56.5 6 11.2	1/23 (4%); 4/24 (17%)	Multilevel CSM	NA	NA	NA	NA	10–14 years after surgery
Seichi et al.⁹ 2004	114(79;35)	62 years (range 33–86 years)	9 (7.9%)	Cervical spondylosis; OPLL; rheumatoid arthritis;	NA	Immediately to 4 and 6 days after surgery—3 and 23 months	NA	An intramedullary lesion 3 weeks after surgery	9-46 mos
Dai et al.³ 1999	287	56 (37–74)	37(12.9%)(27 male;10 female)	CSM; OPLL	NA	4 h to 6 days after surgery(mean 15 h); 5.4 months (2 weeks to 3 years)	Nine were graded as mild, 10 as moderate, and seven as severe	Tethering of the nerve root; OPLL; the duration of complete recovery of postoperative radiculopathy	>3 years
Ohashi et al.³⁴ 2014	121(87,34)(C5G) 115(81,34)(NC5G)	64 ± 10.2; 63.6 ± 12.3	2(1.7%); 8(7.0%)	CSM; CSR; OPLL; CDH	6 on the right side and 4 on the left side	NA	NA	C2–C7 lordosis	2 years
Bydon et al.²⁶ 2014	41	63.31 ± 9.73(palsy); 64.75 ± 11.54(NP)	9(6,3;22.0%)	Degenerative spinal disease	NA	NA	NA	Wider posterior decom pressions; greater widening of the C5 foramen; dural expansion; posterior cord shift	26.11 ± 17.22; 27.56 ± 38.73
Chang et al.²⁰ 2013	68(45;23)	62.4 11.7	6/68 (8.8%)	CSM; OPLL; CDH	NA	2.5 days on average—NA	2.1 ± 1.5	When patients with cervical lesions underwent multilevel decompression surgery, particularly via the combined anterioreposterior approach.	NA
Lubelski et al.³⁵ 2014	98	C5P62 ± 11.3 years; and in the non-C5P 57 ± 12.9 years	12(12%)	Mostly CSM	NA	NA	NA	Anteroposterior diameter; foraminal diameter	NA
Nakashima et al.²⁹ 2012	84(45,39)	60.1 years (range 27–90 years)	10(11.9%)	CSM, OPLL, CDH, CSA, and others	NA	1 day (7), 2 days(2), 10 days in 1;7.9 months (range 7 days–18 months)	A mean MMT score of 3.0 (range 2–4)	OPLL, posterior shift of the spinal cord (C4–5), and postoperative intervertebral foraminal stenosis (C4–5)	4.1 years (range 6–168 months)
Wu et al.³⁰ 2014	102 patients (76 men and 26 women)	58.7 years (range 35–81 years)	16(13 men and 3 women, average age 62.8 years;15.7%)	Multilevel cord compression and/or spinal canal stenosis	6 on the hinge side;8 on the open side, 2 on both sides	A mean of 3.43 days (range 1–14 days)	Between 2 and 4	OPLL, cervical open-door laminoplasty together with posterior instrumented fusion, and width of the intervertebral foramen at C5	NA
Bydon et al.²³ 2014	511(333,178)	65.0 ± 11.8	44(8.6%)	CSM, OPLL	NA	NA	NA	older age	27.6 months

CP: C5 palsy; FU: follow-up; yrs: years; mos: months; NA: not available; A and B group: A and group B in comparative study; MMT: manual muscle test; CSM: cervical spondylotic myelopathy; CSA: cervical spondylotic amyotrophy; CDH: cervical disk herniation; OPLL: ossification of longitudinal ligament; FG: foraminotomy group; NFG: non-foraminotomy group; LP: laminoplasty; CSR: cervical spondylotic radiculopathy; HIZ: high intensity; MVP: motor-evoked potential.

Risk factors

Age

The mean age at time of surgery was 40.25–70.00 years (Table 1). Of the 28 included studies, 5 listed age as the main risk factor. These five studies found that older age increased the risk of developing C5 palsy after posterior cervical surgery.^16,20–23 However, another five studies found no relation between age and the development of C5 palsy after surgery.^2,5,24–26 None of these studies further analyzed the relationship between this potential risk factor and C5 palsy development.

Gender

Seven out of the 28 included studies discussed whether sex influenced the incidence rate of C5 palsy (Table 1). Two out of these seven studies found that male gender was a risk factor for C5 palsy. Nassr et al. determined that the incidence of C5 nerve palsy after cervical spine decompressive procedures was 6.7%, with an increased risk in male patients²²; Nakamae et al. found that the incidence was 3.8% in males, which was significantly higher than the incidence in females of 1.9%.¹⁶ The remaining five studies found no correlation between gender distribution of patients and C5 palsy after surgery.^2,5,24,26,27

Type of disease

The top three diagnoses were cervical spondylosis myelopathy (CSM), OPLL, and cervical disk herniation (CDH; Table 1). However, eight studies reported that patients diagnosed with OPLL had a higher tendency to develop C5 palsy than those with multilevel CDH or CSM.^{3,6,16,21,24,28–30} Therefore, the type of disease had a significant relationship with postoperative C5 palsy development.

Preoperative foraminal stenosis

Foraminal stenosis is a recognized risk factor for C5 palsy, especially stenosis at the C4–C5 level (Table 1). The width of the foramen can be measured by a computed tomography (CT) scan of the cervical spine. Ten studies supported the concept of a relationship between C5 palsy and foraminal stenosis.^{2,7,26,30–35} This adds the possibility that the etiology of C5 palsy is impairment of the C5 nerve root induced by a preexisting foraminal stenosis in patients who undergo posterior cervical surgery.

Surgical procedure

Two studies demonstrated that the use of internal fixation with fusion might add to the risk of C5 palsy. This was because iatrogenic foraminal stenosis may develop from an anterolisthetic vertebra being pulled posteriorly by the “lag correction effect” of the instrumentation. The cervical alignment correction with instrumentation may also increase tension of the roots and cord by posteriorly shifted cord more than those without the correction.^36,37

One study showed significant evidence indicating a higher risk of postoperative C5 palsy in open-door laminoplasty than in double-door laminoplasty; asymmetric decompression by open-door laminoplasty might introduce imbalanced rotational movement of the spinal cord and thus result in C5 palsy.²⁸ Two studies found that an increasing number of corpectomy levels had a higher incidence of C5 palsy.^21,23 One study reported that the incidence of C5 nerve palsy was highest for the laminectomy and fusion group, followed by the anterior corpectomy with posterior fusion group, the anterior-corpectomy-alone group, and finally the laminoplasty group.²² However, another study found no differences in the incidence of C5 palsy among the surgical procedures when investigating anterior decompression and fusion laminoplasty versus laminectomy, or anterior versus posterior procedures.²¹

Radiological assessment

Radiological examination included plain radiography, CT, and magnetic resonance imaging (MRI). The measurement parameters were defined as cervical alignment (C2–C7 Cobb angle), anteroposterior diameter (APD) of the spinal canal, cord-lamina angle (CLA), and high intensity areas (HIZ). One study reported that the cervical alignment was changed by traction of the internal fixation during surgery, which caused a significant cervical curvature index change rate between the palsy group and the non-palsy group³⁷; this study indicated that cervical alignment and cervical curvature index change rate were risk factors for C5 palsy. Another study found that a postoperative increase in cervical lordosis might be the cause of postoperative nerve root palsy.⁶ Using CT scan results, one study suggested that greater CLA and APD can lead to posterior bowing and stretching following decompression.³⁵ Patients that have higher CLAs are theoretically predisposed to having more tethering of the C5 root following posterior decompression, which leads to the development of C5 palsy. Preoperative and postoperative MRI may also be able to predict C5 palsy; two studies found that the detection of HIZ in preoperative MRI and the expansion of this HIZ after surgery might be the reason for C5 palsy.^9,32 However, three other studies found no correlation between HIZ and the development of C5 palsy.^2,8,24

Discussion

Posterior cervical decompression surgery is generally considered safe and effective for cervical compressive myelopathy, but postoperative problems, such as C5 palsy, axial pain, restriction of neck movement, and loss of lordotic curvature, are also reported.² Although the incidence of C5 palsy is generally low, affected patients suffering from persistent muscle weakness, brachialgia, or numbness are dissatisfied with their surgery. It also puts a substantial burden on the patients’ economy and quality of life.^18,20,38 Hence, we conducted a systematic review to further investigate the risk factors for C5 palsy.

C5 palsy is recognized as a serious complication after cervical surgery. However, there are still several separate definitions of the condition. Takemitsu et al. defined postoperative C5 palsy as paresis of the deltoid muscle that develops after cervical spine surgery with no deterioration of myelopathy, with the deltoid muscle showing one or more grades of deterioration after surgery.³⁶ Katsumi et al. defined C5 palsy as deltoid muscle weakness of MMT grade 3 or less without any deterioration of myelopathic symptoms after surgery.²⁵ Liu et al. defined postoperative C5 palsy as paresis of the deltoid muscle that develops after cervical spine surgery with no deterioration of myelopathy.³⁷ Nakashima et al. defined C5 palsy as postoperative deterioration of muscle strength in the deltoid by one or more grades (determined by MMT on the deltoid muscle, with or without involvement of the biceps muscle), but no loss of strength in other muscles.²⁹ Yang and Fuh defined C5 palsy as upper extremity palsy weakness of grade 4 or less of the key muscles in the upper extremity by MMT without any deterioration of myelopathic symptoms after surgery.³⁸ A unified definition should be put forward in the future.

As mentioned above, C5 palsy is usually an early complication after posterior cervical surgery. Our systematic review found that the time of C5 palsy occurrence ranged from immediately to 2 months after surgery. Some studies also reported the occurrence of delayed onset C5 palsy. Yone et al. reported two cases of C5 palsy that occurred 5 and 7 years after surgery; they suggested that nerve roots may occasionally be compressed by degenerated facet joints and spurs that have developed at the entrance of root canal, resulting in segmental motor paralysis several years after laminoplasty.³⁹ Hence, careful long-term observation is necessary after cervical surgery.

C5 palsy is a common complication of postoperative cervical surgery, and although there have been several hypotheses regarding its etiology over the past years, the pathogenesis remains unidentified and many controversies remain. Two main pathogeneses were included in previous studies: the root involvement hypothesis and the spinal cord impairment hypothesis.

The root involvement hypothesis

Until the early 1990s, postoperative C5 palsy was considered to result from surgical trauma to the nerve root caused by instrumentation.^11,36,37 Another hypothesis concerns a tethering phenomenon in which a nerve root lesion might be produced by traction because of a posterior shift of the spinal cord in association with anchoring of the nerve root at the edge of the uncovertebral joint and/or the superior facet.^{3,15,24,25,36,37} This hypothesis appears compatible with the anatomical features of C5 and the tendency toward unilateral shoulder pain and weakness of the deltoid muscle,¹¹ but it cannot explain why some cases occur several days and even months after surgery. Hence, the spinal cord impairment hypothesis was developed.

The spinal cord impairment hypothesis

The spinal cord impairment hypothesis involves segmental spinal cord disorder, spinal cord ischemia, and reperfusion injury to the spinal cord.

Segmental spinal cord disorder

HIZ in the spinal cord were seen on postoperative T2-weighted MRIs and were observed to expand after surgery on C3–C4 and C4–C5 in patients with C5 palsy.^2,9,32 Hence, researchers have postulated that C5 palsy may be associated with pathological damage to anterior horn cells at the gray matter of the spinal cord.

Spinal cord ischemia

Komagata et al. proposed that postoperative C5 palsy may result from ischemia of the spinal cord due to decreased blood supply from the radicular artery. They reported that the cervical cord is mainly perfused by the radicular arteries, and that the radicular artery at the C5 segment is the major source of blood supply. The fact that C5 palsy generally has a good prognosis for a functional recovery might support this idea.³¹

Reperfusion injury of the spinal cord

Rapid reperfusion by oxygenated blood to the ischemic tissue might cause cellular injury and a paradoxical decrease in blood flow after surgery. Chiba et al. proposed that postoperative upper extremity paresis may be caused by deterioration of gray matter, and that local reperfusion injury in the spinal cord could be the pathomechanism.⁸

Every theory remains hypothetical because of non-availability of reliable evidence for verifying their proposed mechanism.

Several preventive measures have been put in place to address the issue of postoperative C5 palsy, including intraoperative monitoring and modified surgery. In an effort to reduce postoperative C5 nerve root palsy, Fan et al. suggested the clinician should consider intraoperative deltoid and biceps transcranial electrical motor-evoked potential (MEP) and spontaneous electromyography monitoring whenever there was potential for iatrogenic C5 nerve root injury.⁵ Yanase et al. reported a significantly higher incidence of waveform pattern changes in the paralytic muscle group than in the non-paralytic muscle group on monitoring of the intraoperative MEP.³³ However, Tanaka et al. observed no abnormalities on transcranial electric MEP monitoring, even in those patients who developed postoperative transient C5 palsy.⁴⁰ Therefore, intraoperative MEP monitoring is not an infallible way to prevent C5 palsy.

As to the surgical technique, several modified surgeries have been put forward to avoid the development of C5 palsy (Table 2). After a retrospective review of 305 patients, Komagata et al. declared that bilateral partial foraminotomy was effective for preventing C5 palsy.³¹ Chiba et al. suggested that expansive open-door laminoplasty is the treatment of choice for cervical compressive myelopathy, giving favorable surgical outcomes and reduced prevalence of C5 palsy.⁸ Radcliff et al. declared that a wider laminectomy at C5 was associated with an increased risk of postoperative C5 palsy.²⁷ Elective cervical laminectomy and fusion might be useful in avoiding C5 palsy. Dai et al. and Bydon et al. both proposed that longitudinal durotomy during cervical decompression surgery could reduce the prevalence of C5 palsy.^3,26 Since the use of internal fixation with fusion might add to the risk of C5 palsy for iatrogenic foraminal stenosis that develops from the cervical alignment correction with instrumentation, some studies suggested prophylactic foraminotomy is recommended to prevent this complication if foraminal stenosis exists preoperatively.^36,37 However, some modified surgery techniques also have their shortcomings. Ohashi et al. reported that prophylactic bilateral C4–C5 foraminotomy might affect cervical alignment and stability, hinge problems, and axial pain.³⁴ Thus, we recommend an individualized surgical plan for patients with cervical degenerative disease.

Table 2.

Modifications of posterior cervical surgery techniques for reduction of C5 palsy.

References	Modified techniques
Komagata et al.³¹	Bilateral partial foraminotomy
Chiba et al.⁸	Expansive open-door laminoplasty
Radcliff et al.²⁷	Elective CLF
Dai et al.³ and Bydon et al.²⁶	Longitudinal durotomy during cervical decompression surgery

CLF: cervical laminectomy and fusion.

Previous studies have shown that conservative therapy methods, such as rest, muscle strength rehabilitation, range of motion exercises in bed, hyperbaric oxygenation, and low-frequency sound waves, are usually successful in treating C5 palsy.^{11,17,19,21,23} However, some cases require additional surgery such as foraminotomy to achieve better results.^7,8,29,30,35 Considering these cases, there might not be a single reliable treatment for postoperative C5 palsy because of its multifocal pathology.

Patients who developed C5 palsy generally had good recovery from neurological and functional deficits. Our review found that the full recovery time ranged from 48 h to 41 months. However, not every patient who experienced C5 palsy recovered from the deficit; irreversible cases of C5 palsy were also reported, especially in the severely paralyzed cases (MMT ≤ 2). Greiner-Perth et al. reported two cases of only partial recovery in 10 patients with C5 palsy, with duration of complete recovery related to the degree of motor impairment.⁴¹ Severely paralyzed cases (MMT ≤ 2) required significantly longer recovery periods than mildly paralyzed cases, especially in patients with OPLL and patients experiencing persistent muscle weakness.^3,34 Residual deficits were defined as failure to return to full motor strength in either the deltoid or biceps brachii, sensory deficit in the C5 distribution, or increased pain in the C5 distribution compared to preoperative status.²²

C5 palsy has been reported mainly after posterior cervical surgery, but can also be seen after surgery using the anterior approach. Kim et al. reported that 6 of 134 patients suffered from C5 palsy after anterior cervical discectomy fusion, and 2 patients with C5 palsy had significant weakness of the deltoid muscle (MMT grade 1)¹¹; the authors conducted foraminotomy on these two patients and only one showed full recovery. Hashimoto et al. also reported that 17 of 199 patients who underwent anterior decompression surgery and spinal fusion suffered from C5 palsy.¹² Thus, surgeons should also consider the possibility of postoperative C5 palsy occurrence when conducting anterior cervical surgery.

Two previous systematic reviews have been conducted regarding C5 palsy. Sakaura et al. from Osaka University mainly focused on the mechanism of C5 palsy,¹³ whereas the review published by Gu et al. from Changzheng Hospital concentrated on its risk factors.¹⁴ In contrast, our systematic review is a complete review of C5 palsy that includes discussion of its clinical features, risk factors, mechanism, and preventive measures. Owing to methodological shortcomings in studies included in this systematic review, the results from different studies may vary because of differences in study design, evaluation criteria, sample size, and incidence or severity of C5 palsy.

Conclusion

The result of this systematic review suggests that patients with older age, male gender, preexisting intervertebral foraminal stenosis, and/or OPLL are at high risk for postoperative C5 palsy. Risk reduction options should be considered for such patients. Further study is needed to clarify the etiology and pathological mechanisms underlying C5 palsy after laminoplasty, and consequently to establish effective measures for prevention of this serious complication.

Footnotes

Authors’ Note

No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Funded by The National Natural Science Foundation of China (81201418, 81572181).

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C5 nerve root palsy after posterior cervical spine surgery

Abstract

Background:

Objective:

Materials and methods:

Results:

Conclusion:

Keywords

Introduction

Materials and methods

Results

Clinical features

Risk factors

Age

Gender

Type of disease

Preoperative foraminal stenosis

Surgical procedure

Radiological assessment

Discussion

The root involvement hypothesis

The spinal cord impairment hypothesis

Segmental spinal cord disorder

Spinal cord ischemia

Reperfusion injury of the spinal cord

Conclusion

Footnotes

Authors’ Note

Declaration of conflicting interests

Funding

References