Postoperative Changes at the Lower End of Cervical Laminoplasty

Severe C8 or T1 Symptoms after Cervical Laminoplasty and Related Factors: Are Tere Any Differences between C3-C6 Laminoplasty and C3-C7 Laminoplasty?

Study Design

Retrospective study.

Purpose

We experienced the situation wherein some patients had new-onset pain or dysesthesia around the ring and little fingers (C8 symptom) or ulnar aspect of the forearm (T1 symptom) after cervical laminoplasty (LP). We investigated the incidence and the cause of new C8 or T1 symptoms and the clinical outcomes after C3–C6 LP or C3–C7 LP.

Overview of Literature

There were some reports regarding complications after cervical LP. However, there was no report regarding C8 or T1 symptoms after cervical LP.

Methods

Among the 33 patients enrolled in this study, 11 and 22 patients were treated with C3–C6 LP and C3–C7 LP, respectively. We prospectively evaluated C8 or T1 symptoms daily postoperatively for 1 week. The distance of the posterior spinal cord shifting and posterior subarachnoid space from C2 to T1 was measured by T2-weighted midsagittal magnetic resonance imaging (MRI). We evaluated pre- and postoperative axial neck pain, Japanese Orthopaedic Association (JOA) score, and JOA score improvement rate.

Results

C8 or T1 symptoms occurred in five and three patients with C3–C6 LP (45.5%) and C3–C7 LP (13.6%), respectively. The distance of the posterior subarachnoid space in C3–C6 LP at C7 was significantly shorter than that in C3–C7 LP at T1 on MRI 24 hours postoperatively (p=0.0448). Postoperative axial neck pain, pre- and postoperative JOA scores, and JOA score improvement rate were not significantly different.

Conclusions

The incidence of C8 or T1 symptoms in C3–C6 LP was higher than that in C3–C7 LP. C8 or T1 symptoms would be caused by the posterior fila radicularia and spinal cord impingement on the intact lower end of the lamina.

Spinal motion preservation surgery: indications and applications

Fusion is one of the most commonly performed spinal procedures, indicated for a wide range of spinal problems. Elimination of motion though results in accelerated degeneration of the adjacent level, known as adjacent level disease. Motion preservation surgical methods were developed in order to overcome this complication. These methods include total disc replacement, laminoplasty, interspinous implants and dynamic posterior stabilization systems. The initial enthusiasm about these methods was followed by certain concerns about their clinical usefulness and their results. The main indications for total disc replacement are degenerative disc disease, but the numerous contraindications for this method make it difficult to find the right candidate. Application of interspinous implants has shown good results in patients with spinal stenosis, but a more precise definition is needed regarding the severity of spinal stenosis up to which these implants can be used. Laminoplasty has several advantages and less complications compared to fusion and laminectomy in patients with cervical myelopathy/radiculopathy. Dynamic posterior stabilization could replace conventional fusion in certain cases, but also in this case the results are successful only in mild to moderate cases.

Two-year clinical and radiological outcomes of open-door cervical laminoplasty with prophylactic bilateral C4-C5 foraminotomy in a prospective study

STUDY DESIGN

A prospective study.

OBJECTIVE

To evaluate the 2-year outcomes of open-door cervical laminoplasty with prophylactic bilateral C4-C5 foraminotomy.

SUMMARY OF BACKGROUND DATA

A prospective trial of prophylactic bilateral C4-C5 foraminotomy with open-door laminoplasty for cervical compression myelopathy showed a significant efficacy for preventing postoperative C5 palsy. However, in bilateral foraminotomy, there are concerns such as postoperative instability, hinge fracture, or nonunion, which may cause deterioration of neurological symptoms and neck pain.

METHODS

A prospective trial was performed in 141 patients between 2009 and 2010 (group F). A group of 141 patients who underwent open-door laminoplasty without prophylactic foraminotomy from 2006 to 2008 served as a control group (group NF). Here, we report 2-year radiological and clinical data for 121 patients (follow-up rate: 85.8%) in group F and 115 patients (81.6%) in group NF. The 2 groups were demographically similar, except for the operation time.

RESULTS

In group F, the mean rate of facet joint preservation was 71.4%. C2-C7 and C4-C5 lordosis and C4 translational movement were maintained postoperatively in both groups. The range of motion of C2-C7 and C4-C5 significantly decreased to about 80% of the preoperative values in both groups (P < 0.01). These radiological parameters and the incidence of hinge fracture and nonunion did not differ significantly between the groups. Visual analogue scale scores for neck pain were unchanged and significant recoveries (P < 0.001) in Japanese Orthopaedic Association scores were found in both groups. There were no significant differences in these clinical scores between the groups. The incidences of C5 palsy were 1.7% and 7.0% in groups F and NF, respectively (P = 0.043).

CONCLUSION

Prophylactic bilateral C4-C5 foraminotomy did not adversely affect the 2-year radiological and clinical outcomes. Therefore, we conclude that this approach is an effective and desirable procedure for preventing postoperative C5 palsy.

LEVEL OF EVIDENCE

3.

The relationship between the anatomy of the nuchal ligament and postoperative axial pain after cervical laminoplasty: cadaver and clinical study

STUDY DESIGN

A cadaver and clinical study investigated the attachment of the nuchal ligament to the cervical spinous process.

OBJECTIVE

To investigate the anatomical details of the attachment of the nuchal ligament to the spinous process and the relationship between the morphology of the nuchal ligament and postoperative axial pain after laminoplasty.

SUMMARY OF BACKGROUND DATA

The relationship between the length of the C6 spinous process and the morphology of the nuchal ligament and occurrence of postoperative axial pain has not been elucidated.

METHODS

The morphology of the nuchal ligament was investigated in 35 cadavers and 60 patients on preoperative computed tomography and magnetic resonance imaging. The lengths of the C6 and C7 spinous processes were measured, and the C6:C7 ratio (C6 spinous process length/C7 spinous process length) was calculated. The relationship between the morphology of the attachment of nuchal ligament to the C6 spinous process and the C6:C7 ratio were investigated. In addition, the effects of the anatomy of the nuchal ligament around the C6 spinous process and different procedures of surgical invasion to C6 or C7 on postoperative axial pain were investigated for 113 patients who underwent laminoplasty.

RESULTS

The nuchal ligament was attached to not only the C7 spinous process, but also the C6 spinous process when the C6:C7 ratio was more than 0.8. When the nuchal ligament was attached to the C6 spinous process and to C7, postoperative axial pain after C3-C7 laminoplasty occurred more often compared with C3-C6 laminoplasty for patients without the nuchal ligament attached to the C6 spinous process.

CONCLUSION

This study shows that there is an association between the individual anatomical differences of the nuchal ligament and the occurrence of postoperative axial pain after laminoplasty. Careful attention should be paid to the morphology of the attachment of the nuchal ligament to the C6 spinous process to reduce postoperative axial pain.

Neck muscle strength before and after cervical laminoplasty: relation to axial symptoms

STUDY DESIGN

A prospective study to investigate serial changes in neck muscle strength before and after cervical laminoplasty.

OBJECTIVES

To examine the correlation between neck muscle strength and axial symptoms, and to clarify the risk factors for axial symptoms.

SUMMARY OF BACKGROUND DATA

Axial symptoms are common complications after posterior cervical spinal surgery. Although several technical considerations have reduced axial symptoms, the causes of axial symptoms are still largely unknown. Previous studies have indicated that neck muscle strength is reduced in patients with neck pain.

MATERIALS AND METHODS

Nineteen consecutive patients underwent cervical expansive laminoplasty for cervical spondylotic myelopathy. Age, sex, operative time, blood loss, clinical results, cervical curvature, range of motion, visual analog scale (VAS) for axial symptoms, and manual muscle strengths were examined before and after surgery. At 3 and 12 months, these factors were compared statistically between the no pain (NP) group (VAS <3) and the pain (P) group (VAS >or=3). The correlation between VAS and neck muscle strength, and the reduction in neck muscle strength in extension were analyzed statistically.

RESULTS

Six patients (31.5%) complained of axial symptoms at 3 months, and the symptoms continued in 3 patients (15.8%) at 12 months. At 3 months, cervical lordosis was 15.7 degrees in the NP group and 5.0 degrees in the P group, and neck strength in extension was 104.9% and 61.8%, respectively. At 12 months, neck strength in extension was 124.3% and 62.2%, respectively. These differences were statistically significant. The correlation between neck pain VAS and neck muscle strength, and the reduction in neck muscle strength in extension were statistically significant.

CONCLUSIONS

Neck muscle strength recovered to the preoperative value by 3 months and increased to 120% by 12 months in the NP group, whereas in the P group, neck muscle strength remained reduced by 60% and did not recover. Neck muscle strength and axial symptoms were strongly correlated.

Surgical anatomy of the nuchal muscles in the posterior cervicothoracic junction: significance of the preservation of the C7 spinous process in cervical laminoplasty

STUDY DESIGN

An anatomic study investigated the attachment of the nuchal muscles to the spinous process.

OBJECTIVE

To investigate the anatomic details of the attachment of the nuchal muscles to the spinous process, and which muscles are spared, and to what extent, when the C7 spinous process is preserved in the cervical laminoplasty.

SUMMARY OF BACKGROUND DATA

In previous studies, it was reported that the incidence of postoperative axial pain was lower in C3-C6 laminoplasty than in C3-C7 laminoplasty, emphasizing the effectiveness of the former procedure where discission of the nuchal muscles that are attached to the C7 spinous process is avoided. However, there have been no detailed anatomic studies of the attachment of the nuchal muscles to the spinous process at the cervicothoracic junction.

METHODS

The anatomy of the speculum rhomboideum of the trapezius, rhomboideus minor, rhomboideus major, serratus posterior superior, splenius capitis, and splenius cervicis to the spinous processes of the cervicothoracic junction were studied using 50 cadavers.

RESULTS

The possibility of total discission of the speculum rhomboideum of the trapezius was 0% with C3-C6 laminoplasty and 18% with C3-C7 laminoplasty. More than 50% preservation of the speculum rhomboideum of the trapezius is possible in 72% in C3-C6 laminoplasty and 16% in C3-C7 laminoplasty. In C3-C7 laminoplasty, the possibility of partial preservation of the rhomboideus minor, serratus posterior superior, and splenius capitis at the spinous process was 0%, 66%, and 29%, respectively. The rhomboideus major in 16% and the splenius cervicis in 56% could be completely preserved without partial discission of the muscle attachment. On the other hand, in C3-C6 laminoplasty, the muscles that were spared without complete discission of the muscular attachment at the spinous process were the rhomboideus minor in 35%, the serratus posterior superior in 100% and the splenius capitis in 67%. The rhomboideus major in 76% and the splenius cervicis in 80% were completely spared without partial discission of the muscular attachment.

CONCLUSION

The current study confirmed that C3-C6 laminoplasty in which the C7 spinous process is preserved reduces invasion of the nuchal muscles.

The source of axial pain after cervical laminoplasty-C7 is more crucial than deep extensor muscles

STUDY DESIGN

Prospective study to investigate the incidence of axial pain in the 3 different procedures of laminoplasty.

OBJECTIVE

To inquire which is more important in the development of axial pain after laminoplasty: C7 or deep extensor muscles.

SUMMARY OF BACKGROUND DATA

The etiology of axial pain remains largely unknown. Some surgeons have attempted to preserve the paravertebral muscles with innovative procedures of laminoplasty and thereby reduce the incidence of axial pain. Meanwhile, we have reported that axial pain can be prevented by avoiding inclusion of C7 in laminoplasty.

METHODS

There were 91 patients with myelopathy who underwent our original laminoplasty, in which the deep extensor muscles were completely preserved exclusively on the hinged side. Until 2001, all candidates for laminoplasty underwent this procedure from C3-C7 (left-opened C3-C7 group, n = 37). From 2002, the same procedure was performed from C3-C6 (left-opened C3-C6 group, n = 31). From 2004, the opened side was changed from left to right (right-opened C3-C6 group, n = 23). Axial neck pain was graded as severe, moderate, or mild. Early pain during the first month after surgery and late pain during the first year after surgery were investigated. The laterality of early pain in the C3-C6 groups was recorded.

RESULTS

Significant early pain graded severe or moderate was observed in 49% in the left-opened C3-C7 group, but 15% in the left- or right-opened C3-C6 groups (P = 0.0008). Significant late pain was noted in 30% in the left-opened C3-C7 group and in 5.6% in the C3-C6 groups (P = 0.0036). Early axial pain, which usually was mild, was predominantly observed on the opened side in the C3-C6 groups.

CONCLUSION

To prevent axial pain, C7 should not be included in cervical laminoplasty, while detachment of the deep extensor muscles does not result in significant axial pain.