Outcomes after surgery for cervical spine deformity: review of the literature

Arnold B. Etame M.D., Anthony C. Wang M.D., Khoi D. Than M.D., Frank La Marca M.D., and Paul Park M.D.
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  • Department of Neurosurgery, University of Michigan Health System, Ann Arbor, Michigan
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Object

Symptomatic cervical kyphosis can result from a variety of causes. Symptoms can include pain, neurological deficits, and functional limitation due to loss of horizontal gaze.

Methods

The authors review the long-term functional and radiographic outcomes following surgery for symptomatic cervical kyphosis by performing a PubMed database literature search.

Results

Fourteen retrospective studies involving a total of 399 patients were identified. Surgical intervention included ventral, dorsal, or circumferential approaches. Analysis of the degree of deformity correction and functional parameters demonstrated significant postsurgical improvement. Overall, patient satisfaction appeared high. Five studies reported mortality with rates ranging from 3.1 to 6.7%. Major medical complications after surgery were reported in 5 studies with rates ranging from 3.1 to 44.4%. The overall neurological complication rate was 13.5%.

Conclusions

Although complications are not insignificant, surgery appears to be an effective option when conservative measures fail to provide relief.

Abbreviations used in this paper: CBV = chin-brow vertical; JOA = Japanese Orthopaedic Association.

Object

Symptomatic cervical kyphosis can result from a variety of causes. Symptoms can include pain, neurological deficits, and functional limitation due to loss of horizontal gaze.

Methods

The authors review the long-term functional and radiographic outcomes following surgery for symptomatic cervical kyphosis by performing a PubMed database literature search.

Results

Fourteen retrospective studies involving a total of 399 patients were identified. Surgical intervention included ventral, dorsal, or circumferential approaches. Analysis of the degree of deformity correction and functional parameters demonstrated significant postsurgical improvement. Overall, patient satisfaction appeared high. Five studies reported mortality with rates ranging from 3.1 to 6.7%. Major medical complications after surgery were reported in 5 studies with rates ranging from 3.1 to 44.4%. The overall neurological complication rate was 13.5%.

Conclusions

Although complications are not insignificant, surgery appears to be an effective option when conservative measures fail to provide relief.

Abbreviations used in this paper: CBV = chin-brow vertical; JOA = Japanese Orthopaedic Association.

Cervical spine deformity is an uncommon but potentially debilitating condition with multiple causes, including but not limited to spondylosis, inflammatory arthropathy, trauma, infection, iatrogenic, neoplastic, congenital, and neuromuscular processes. Sagittal plane deformities result in kyphosis, whereas coronal plane deformities lead to a scoliotic configuration. The most common cause of cervical kyphotic deformity is prior surgical destabilization.2,4 Scoliotic deformities are mostly encountered in congenital and neuromuscular conditions.

Progressive cervical kyphosis can cause neurological symptoms, such as myelopathy.8 Moreover, severe kyphotic deformities, as seen in spondylitic arthropathies, can lead to a chin-on-chest deformity with significant compromise of horizontal gaze, swallowing, and breathing.3,16 Even in the absence of neurological symptoms, the pain associated with deformity contributes to functional disability.

Surgical intervention remains an option for patients with progressive symptomatic cervical kyphosis in whom conservative treatment has failed. Surgery can be accomplished through multiple approaches. Correction can be ventral,4,6,12,29 dorsal,1,5 or through a combined ventraldorsal approach.1,11,15,22 The overall surgical objectives entail correction of deformity and decompression of neural elements.

The increased potential for neurological morbidity associated with deformity correction greatly underscores the utility of functional outcome data. A recent review of outcomes in patients who underwent corrective surgery for cervicothoracic kyphosis due to a specific cause, ankylosing spondylitis, supported the effectiveness of surgery.7 However, the long-term outcome for individuals undergoing surgery for symptomatic cervical kyphosis caused by other factors has not been systematically studied. Hence, we systematically reviewed the literature to assess functional and radiographic outcomes in all patients, regardless of cause, who underwent kyphotic deformity correction in the subaxial cervical spine.

Methods

A comprehensive literature search was performed using the PubMed database for all journal articles published until October 2009. Key words used in the search included “cervical deformity,” “cervical kyphosis,” “correction,” “surgery,” and “fusion;” terms were searched individually or in combination. The appropriate articles for our study were subsequently selected using several criteria. Only studies that specifically addressed surgical correction of cervical kyphosis were selected. In addition, outcome data with respect to the degree of kyphosis correction as well as functional outcome had to be included in the study. We excluded case reports, case series with fewer than 5 patients, as well as series that did not incorporate outcome parameters. Using the above criteria, we identified 14 retrospective clinical studies that described postsurgical outcomes following deformity correction for cervical kyphosis.

Results

Patient Demographics

We identified 14 clinical studies that described a total of 399 patients who underwent surgical correction for symptomatic cervical kyphotic deformity. The demographic data are illustrated in Table 1. The mean age at the time of surgery was 52.6 years based on data from 13 of the 14 studies. There was a male predominance of 261 patients (71%) based on 13 studies that included information on sex.1,8,9,12,14,16–18,21,23,26,28,29

TABLE 1:

Demographic data from patients undergoing cervical kyphotic deformity correction*

Authors & YearNo. of PatientsMean Age (Yrs)Male/FemaleMean Follow-Up (mos)Study Type
Zdeblick & Bohlman, 1989144611/331retrospective
Herman & Sonntag, 1994205814/628retrospective
McMaster, 1997154813/218retrospective
Abumi et al., 1999304717/1342retrospective
Steinmetz et al., 200310407/39retrospective
Ferch et al., 2004285717/1125retrospective
Belanger et al., 200526NANA54retrospective
Simmons et al., 200613150112/19103retrospective
Langeloo et al., 2006165114/2min 12 mosretrospective
Tokala et al., 200713546/224retrospective
O'Shaughnessy et al., 200816529/754retrospective
Mummaneni et al., 2008305616/1431retrospective
Gerling and Bohlman, 20089675/472retrospective
Nottmeier et al., 2009416120/2119retrospective

* NA = not available.

Preoperative Assessment

Patients were preoperatively evaluated clinically as well as radiographically. Surgery was generally reserved for patients who were symptomatic from their kyphosis or, in some instances, for patients who demonstrated progression of deformity. Axial neck pain and neurological symptoms of myeloradiculopathy were indications for surgical intervention. Multiple studies used cervical myelopathy as the predominant indicator for correction.8,17,18,21,26 In patients with severe fixed cervicothoracic kyphosis, the significant compromise of horizontal gaze served as the basis for surgical intervention.3,14,16,23,28

Radiographic assessments were used to ascertain the extent of deformity, possible stenosis, and the degree of correction necessary. These studies usually entailed MR imaging, CT scanning, and static and dynamic plain radiographs of the cervical spine.

Surgical Technique

Techniques for correction of cervical spine deformity were quite varied and depended on pathology. In patients with ventral compressive pathologies or compromised integrity of the ventral column, a ventral approach was considered in conjunction with dorsal fusion. If dynamic radiographs suggested a flexible deformity or if the deformity was reducible by traction, correction could be accomplished via a dorsal approach alone. With fixed kyphotic deformities, a ventral approach was usually considered for correction.

Ventral correction with or without fixation was the main surgical modality in 4 clinical studies.8,12,26,29 Zdeblick and Bohlman29 used ventral corpectomies with strut-grafting to treat 14 patients with cervical kyphosis and myelopathy. In a subsequent study, ventral reduction with interbody fusion and ventral plating was used by Herman and Sonntag12 to treat 20 patients who had postlaminectomy kyphosis. Using a ventral strategy, Ferch et al.8 treated 28 patients with progressive myelopathy and cervical kyphosis, mostly due to degenerative spondylosis. Nine patients who had focal canal compression at the disc interspace were treated with discectomies and grafting. The remaining patients who had diffuse canal stenosis underwent corpectomies. Similarly, Steinmetz et al.26 used a ventral approach in their series of 10 patients with progressive kyphosis, presumably caused by prior dorsal and ventral cervical operations. Canal decompression was typically attained either through multiple discectomies or corpectomies. Grafts were secured using either rigid or dynamic constructs.

In situations in which the predominant presentation was kyphosis at the cervicothoracic interface with facet ankylosing,3,14,16,23,28 correction was mainly accomplished through a C7–T1 dorsal osteotomy, as reported by Simmons.24,25 This entailed complete laminectomy of C-7, partial laminectomies of C-6 and T-1, partial pedicle osteotomy, osteoclasis of the ventral vertebral body, and finally correction of the deformity. Reduction was then maintained by either external halo-casting16,23 or internal fixation.3,14,16,28 In instances in which patients exhibited flexible kyphosis, they were treated via a dorsal approach without ventral release.1,9

Combined ventral and dorsal approaches were used in several clinical studies.1,9,17,18,21 In these studies, patients underwent discectomies or corpectomies based on the extent of canal compression. Some patients required ventral osteotomies for correction in the setting of ankylosis. Posterior osteotomies were carried out as needed for decompression and reduction. Instrumented fixation was used ventrally and dorsally.

Intraoperative monitoring was documented in multiple studies.9,12,17,21 This typically entailed somatosensory evoked potential, electromyography, and transcranial motor evoked potential monitoring.

Kyphosis Correction Outcomes

Kyphosis correction outcomes were assessed using several parameters, as illustrated in Table 2. Several studies used the CBV angle as an index of horizontal gaze.14,23,28 The CBV angle, which is ascertained from photographs, measures the angle between the vertical axis of an upright patient and a line drawn from the chin to the brow. In very severe cases, this angle can approach 90° (Fig. 1). Hence, increases in the CBV angle correspond to increased compromise of horizontal gaze. All 3 studies reported significant improvement in CBV angle following surgical intervention (Table 2).14,23,28

TABLE 2:

Postsurgical outcome data for patients undergoing cervical kyphotic deformity correction*

Authors & YearMain Correction ApproachResults
Zdeblick & Bohlman, 1989ventralmean preop kyphosis of 45° corrected to 13° for a mean correction of 32°; most patients experienced residual kyphosis
Herman & Sonntag, 1994ventralmean preop kyphosis of 38° corrected; most patients experienced an average residual kyphosis of 13°
McMaster, 1997dorsalmean preop kyphosis of 23° corrected to 31° for mean correction of 54°; mean loss of correction at FU of 6°
Abumi et al., 1999dorsal/combinedmean preop kyphosis of 29.4° corrected to 2.3°; dorsal correction improved kyphosis from 28.4 to 5.1° in 17 patients; combined dorsal/ventral correction in 13 patients improved kyphosis from 30.8 to 0.5° at FU
Steinmetz et al., 2003ventralmean correction 20° w/ mean loss of 2.2° at FU; w/ exception of 1 patient, lordotic curvature was attained in all
Ferch et al., 2004ventral26/30 patinets improved toward lordosis w/ a mean local sagittal angle correction of 14° & mean regional sagittal angle correction of 11°; 4 patients had persistent kyphosis
Belanger et al., 2005dorsalmean correction 38° w/ a mean loss of 3° at FU
Simmons et al., 2006dorsalCBV angle improved from 56 to 4° in 114 patients treated w/ smaller osteotomy; CBV angle improved from 49 to 12° in 17 treated w/ a wider osteotomy
Langeloo et al., 2006dorsalCBV angle improved from 42 to 5°
Tokala et al., 2007dorsalCBV angle improved from 41 to 6°
O'Shaughnessy et al., 2008combinedbased on Cobb angles, kyphosis improved from a preoperative mean of 38° corrected to 10° for mean correction of 48°
Mummaneni et al., 2008combinedbased on Ishihara indices, kyphosis improved from preop mean of − 17.7° to postop mean of +11.4°
Gerling and Bohlman, 2008dorsal/combinedoverall preop kyphosis was 69.6° w/ a mean correction of 57.1° postop & 41.4° at FU for all 9 patients; in 3 patients w/ dorsal wire constructs, kyphotic correction was lost from 37° postop to 18° at FU; loss of correction was intermediate in 4 patients w/ wire/rod constructs from 69 to 49°; 2 patients w/ rod/screw constructs retained their correction from 64 to 63°; mean correction for dorsal approach was 53.8° & for combined was 61.3°
Nottmeier et al., 2009combinedmean correction of sagittal angle was 24°

*FU = follow-up.

Fig. 1.
Fig. 1.

Diagram illustrating CBV angle, which is the angle between lines A and B. In the figure with the flexion deformity (left) the angle is approximately 90°, while in the figure with near-normal alignment (right) the angle is closer to 0°.

Another radiographic outcome measure is the Ishihara index, which assesses cervical curvatures on the basis of lordosis and kyphosis (Fig. 2).10,13,27 Mummaneni et al.17 reported significant improvement in the mean Ishihara indices from a preoperative kyphotic index of −17.7 to a postoperative lordotic index of +11.4. Some authors reported degrees of kyphotic correction based on comparisons of preoperative and postoperative values.1,3,8,9,16,18,21,26,28,29 Overall, as illustrated in Tables 2 and 3, significant deformity correction was achieved in most cases. However, a subset of patients subsequently lost some degree of correction noted at subsequent follow-up.3,9,16,26

Fig. 2.
Fig. 2.

Diagram showing Ishihara curvature index. On a lateral radiograph, a vertical line (A) is drawn between the dorso-inferior edges of C-2 and C-7. For a1–a4, perpendicular lines are drawn from line A to the dorsoinferior edge of C-3 to C-6. The lines are measured in millimeters. The Ishihara index = (a1+a2+a3+a4)/A × 100.

TABLE 3:

Summary of radiographic outcomes for patients undergoing cervical kyphotic deformity correction

ApproachMean Correction on Radiography
ventral11 to 32° (Cobb angle)
dorsal23.3 to 54° (Cobb angle)
35 to 52° (CBV angle)
combined24 to 61.3° (Cobb angle)*

* Ishihara index was used in only 1 study and, as a result, was not included in the summary table.

Functional Outcome

Functional outcome measures varied between studies, as illustrated in Table 4. In studies in which loss of horizontal gaze was the main surgical indicator, all patients reportedly achieved restoration of horizontal gaze.3,14,16,23,28 Patients were generally satisfied with their surgical outcomes.23,28

TABLE 4:

Postsurgical functional outcome data for patients undergoing cervical kyphotic deformity correction*

Authors & YearMain Correction ApproachResultsStandardized Outcome Measure
Zdeblick & Bohlman, 1989ventralNurick scores improved from preop mean of 3.6 to a postoperative mean of 1.3; 3/4 previously nonambulatory patients were ambulatory at FUno
Herman & Sonntag, 1994ventral2/20 patients experienced complete resolution of sx, 11 experienced substantial improvement in sx, 6 improved w/ respect to pain but not neurologically, & 1 patient who previously improved experienced progressive sxno
McMaster, 1997dorsalhorizontal gaze was restored in all patients; of 15 patients unable to work at time of op, 4 were able to return to workno
Abumi et al., 1999dorsal/combinedsome patients showed improvement in Frankel score; 3/24 myelopathic patients obtained a 2-grade improvement, 11 obtained a 1-grade improvement, & 10 remained stableno
Steinmetz et al., 2003ventralall patients experienced significant improvement in neck pain & myeloradiculopathy sx; 3 patients experienced complete resolution of sxno
Ferch et al., 2004ventralmJOA scores improved in 11 patients, remained stable in 15, & deteriorated in 1; cervical neck pain scores remained unchanged following the opyes
Belanger et al., 2005dorsalhorizontal gaze was restored in all patients; dysphagia sx improved in 18/19 patientsno
Simmons et al., 2006dorsalhorizontal gaze restored in all patients; all patients expressed satisfaction w/ opno
Langeloo et al., 2006dorsalhorizontal gaze restored in all patientsno
Tokala et al., 2007dorsalhorizontal gaze restored in all patients; of 3/8 patients treated, 3 expressed excellent satisfaction w/ op & 5 reported good satisfactionno
O'Shaughnessy et al., 2008combinedmean Nurick scores improved from 2.4 to 1.5 in all 16 patients; similarly, there was improvement in Odom classification w/ 6 patients rated excellent, 8 good, 1 fair, & 1 poor; 9 patients denied dysphagia, 6 reported minor swallowing problems, & 1 major swallowing problemsno
Mummaneni et al., 2008combinedmean Nurick scores improved from 3.2 to 1.2, & mJOA scores improved from 10 to 15 in statistically significant manneryes
Gerling and Bohlman, 2008dorsal/combinedbased on Odom scale, 5 patients had excellent outcome, 2 had good, & 2 had fair; patient satisfaction was reported as excellent by 7 patients & fair by 2 patientsno
Nottmeier et al., 2009combinedin 41 patients, preoperative sx were improved in 39, stable in 1, & worse in 1 patientno

* mJOA = modified Japanese Orthopaedic Association scale.

The Nurick score,19,20 which ranges from 0 to 5 with 5 being considered wheelchair-bound, was the outcome assessment used in several studies.17,21,29 There was a tendency toward improvement of mean Nurick scores following deformity correction. The modified JOA provides an assessment of sensory and motor function in the extremities as well as urinary function. Mummaneni et al.17 noted improvement in modified JOA scores from 10 to 15 at follow-up. When modified JOA scores were assessed by Ferch and colleagues8 in 28 patients with cervical myelopathy, there was improvement in 41% of patients, while 56% remained stable. When patients were assessed for cervical neck pain outcome in the same study, there was no significant difference between preoperative and postoperative neck pain. The authors stressed that neck pain was a secondary indication for surgery, and myelopathy was the main indication. There was also significant improvement in mean Odom outcome grades, suggesting symptomatic improvement.9,21 Gerling and Bohlman9 reported high patient satisfaction rates and improved pain scores. Abumi et al.1 used the Frankel grading system to assess outcomes in 24 patients. Three patients experienced a 2-grade improvement, while 11 patients improved by a single grade. The remaining 10 patients were reportedly stable.

Not every author used a validated functional assessment tool. Steinmetz et al.26 reported improvement in preoperative symptoms in all patients, with a small subset of patients experiencing complete resolution of symptoms. Similarly, Nottmeier et al.18 reported improved preoperative symptoms of neck pain, myelopathy, and radiculopathy in 39 of 41 patients. One patient remained stable while another patient experienced clinical deterioration. When Zdeblick and Bohlman29 corrected cervical kyphosis in 14 patients, there was complete or partial recovery of neural function in 13 patients. In addition, 3 of 4 patients who were previously nonambulatory became ambulatory following surgery. Herman and Sonntag12 reported outcomes in patients with predominantly degenerative kyphosis who were treated by a ventral approach. Of the 20 patients, 2 experienced complete symptomatic resolution, 11 had significant improvement in pain and neurological symptoms, and 7 had improvement in pain but not neurological symptoms.

Complications

A total of 9 surgery-related deaths were reported in 5 of the 14 studies (Table 5).3,8,14,17,23 In these 5 studies, the mortality rate ranged from 3.1 to 6.7%. With these 9 reported cases, the overall surgery-related mortality encompassing all 399 patients from the 14 clinical studies was 2.3% (Table 6). Two studies noted 3 additional deaths that were not related to surgery. In the study by Zdeblick and Bohlman,29 1 patient died of a carcinoma 10 months after surgery, while the other died of a myocardial infarction 6 months after surgery. Ferch et al.8 had a patient who died of pneumonia 3 months after surgery. Major medical complications, such as pulmonary embolism, pneumonia, symptomatic pneumothorax, seizure, and deep venous thrombosis, were noted in 5 of the 14 studies, affecting 13 total patients with rates ranging from 3.1 to 44.4% (Table 5).3,9,12,14,23 Based on 13 cases, the incidence of major medical complication within the series of 399 patients from all 14 studies was 3.3%. A total of 53 neurological complications (13.5%) were reported. The most significant number of neurological complications was seen in patients treated by dorsal osteotomy at the cervicothoracic interface.3,14,16,23,28 In these 5 studies comprising a total of 196 patients, 46 (23.5%) had postoperative neurological deficits. Surgical wound infections were noted in 13 patients for an incidence of 3.3%. This does not take into account the high incidence of halo pin-site infections reported in the series by Simmons et al.23 Ventral graft dislodgments were seen in 3 of 14 patients in the study by Zdeblick and Bohlman.29 Pseudarthrosis rates ranged from 0 to 13.3% in the McMaster series.16 There were a total of 15 reported cases of pseudarthrosis, accounting for an overall incidence of 3.8%.

TABLE 5:

Complications in patients undergoing cervical kyphotic deformity correction

Authors & YearNo. of PatientsResults (no. of patients)
Zdeblick & Bohlman, 198914graft dislodgment & pseudarthrosis (3)
Herman & Sonntag, 199420vocal cord paresis (3); pneumonia (2); wound dehiscence/infection (1); hardware failure (1); deep venous thrombosis (1)
McMaster, 199715quadriparesis (1); C-8 weakness (2); C-8 radiculopathy (4); transient dysphagia (3); wound infection (1); pseudarthrosis (2)
Abumi et al., 199930radiculopathy (2); durotomy (1); wound infection (1)
Steinmetz et al., 200310dysphagia (1); hoarseness (2)
Ferch et al., 200428death (1); wound infection (1); dysphagia (2); residual spinal canal stenosis (1)
Belanger et al., 200526death (1); radiculopathy (5); seizure (1); pseudarthrosis (1)
Simmons et al., 2006131death (4); paraplegia (2); hemiparesis (1); transient C-8 radiculopathy (18); halo-site infection (15); pulmonary embolism (4); pseudarthrosis (6)
Langeloo et al., 200616death (1); C-6 spinal cord injury (1); transient C-8 paresthesia (9); wound infection (2); viral meningitis (1)
Tokala et al., 200713transient C-8 radiculopathy (3); wound infection (2)
O'Shaughnessy et al., 200816quadriplegia (1); C-5 palsy (3); adjacent segment kyphosis not requiring revision (1); durotomy (2); gastrostomy tube (4); tracheostomy (3)
Mummaneni et al., 200830death (2); wound infection (2); durotomy (1); dysphagia (1); pseudarthrosis (1); dysphonia (1); hardware failure (1); gastrostomy tube/tracheostomy (4)
Gerling & Bohlman, 20089pulmonary edema & hypotension (1); pneumonia (1); pneumonia & pneumothorax (1); implant failure & dysphagia (1); dysphagia, gastrostomy tube, & pneumonia (1); periincisional ulcer (1); pseudarthrosis (1)
Nottmeier et al., 200941quadriparesis (1); C-8 radiculopathy (1); pseudarthrosis (1); dysphagia (1); wound dehiscence/infection (3); hardware failure requiring revision (2); adjacent segment kyphosis not requiring revision (3)
TABLE 6:

Summary of complications for patients undergoing cervical kyphotic deformity correction

ComplicationNo. of Patients (% of cohort)
mortality9 (2.3)
major medical complication13 (3.3)
neurological54 (13.5)
durotomy4 (1.0)
dysphagia10 (2.5)*
vocal cord paresis/hoarseness6 (3.4)
pseudarthrosis15 (3.8)
infection13 (3.3)
tracheostomy7 (1.8)
gastrostomy tube9 (2.3)

* Of these 10 patients, 7 underwent a ventral-only or combined procedure. The percentage is based on 176 of the 399 patients who underwent ventral-only or combined approach (4.0%).

† All 6 patients underwent ventral-only or combined approach. The percentage reported is based on 176 patients who underwent ventral or combined approach.

Discussion

Cervical kyphosis can be a progressive, debilitating condition caused by multiple factors. Symptomatic patients can experience axial neck pain, myelopathy, and/or radiculopathy resulting in significant functional limitations. Patients can also experience loss of horizontal gaze, making mundane activities such as swallowing, breathing, or eating a challenging task. When patients remain symptomatic or exhibit disease progression despite conservative therapies, surgical correction is typically considered a high-risk but viable option.

In the preoperative evaluation of patients, all studies reviewed were similar in terms of the general indications for surgery. Surgery was mainly recommended to patients who had pain, significant neurological symptoms, compromise of horizontal gaze, and/or progression of deformity. In the articles in which the predominant etiology was ankylosing spondylitis, the loss of horizontal gaze was the primary indication for surgery.3,14,16,23,28

Surgical management was attained through various approach strategies dictated mostly by anatomical as well as pathological considerations. In several articles in which patients had fixed cervicothoracic kyphosis from ankylosing spondylitis, C7–T1 dorsal wedge osteotomy was the main surgical intervention.3,14,16,23,28 It was reasoned that at this location there was a lower risk to vertebral artery injury. In addition, the nerve root that was most at risk with closure of the osteotomy was the C-8 nerve root, which was less critical for hand function than for other nerve roots. The dorsal approach alone was also most useful in situations in which the kyphosis was reducible without significant residual compression of the spinal canal, as was the case with some patients in the series by Abumi et al.1

In general, ventral-only approaches resulted in mild to moderate deformity correction with mean correction ranging from 11 to 32° (Table 2). Dorsal approaches with osteotomy or circumferential approaches resulted in greater correction. The mean correction ranged from 23.3 to 53.8° and 35 to 52° based on Cobb and CBV angles, respectively, for dorsal approaches. For combined approaches, the mean correction ranged from 24 to 61.3°. In chin-on-chest deformities, often occurring due to ankylosing spondylitis, the dorsal approach with osteotomy was most frequently used with significant correction.

Ventral strategies for correcting kyphosis have evolved. Initial attempts to correct cervical kyphosis through a strictly ventral approach proved to be very challenging. Zdeblick and Bohlman29 reported one of the earlier series of ventral correction by using corpectomies without ventral cervical plating. As a result, there was a higher incidence of graft dislodgment, and most patients were left with residual kyphosis following correction. Herman and Sonntag12 subsequently incorporated ventral cervical plating. Using a combination of rigid and dynamic ventral instrumentation with multiple points of fixation, Steinmetz et al.26 subsequently demonstrated the feasibility of achieving cervical lordosis in kyphotic patients from a ventral approach. Most recently, there has been an increase in combined ventral and dorsal approaches, which appears to be most useful in patients with fixed kyphosis from ankylosed facets. An attractive feature of this procedure is the combination of ventral lengthening and dorsal shortening to attain correction. The feasibility of attaining significant correction with this approach was best demonstrated by Abumi et al.1 In his cohort of 30 patients, 17 were corrected dorsally while the remaining 13 underwent a circumferential approach. While he noted an improvement in kyphosis from 28.4 to 5.1° within the group that had dorsal correction, correction in the combined group was even more impressive, with a preoperative kyphosis of 30.8 to 0.5° at follow-up. The sequence of surgery in combined approaches is also a factor considered in clinical decision-making. In general, the ventral approach was initially undertaken except in situations in which an initial dorsal osteotomy was deemed necessary to enhance correction.

The means of assessing the degree of deformity correction varied among studies, although significant improvement was noted in all studies. However, several studies noted subsequent loss of some degree of correction at follow-up examination.3,9,16,26 McMaster16 reported a mean loss of 6° from a previously corrected mean of 54°, while Belanger et al.3 reported a mean loss of 3° from a corrected mean of 38°. These patients had been treated with dorsal cervicothoracic osteotomies with internal fixation or halo-casting. Gerling and Bohlman9 reported on 9 patients who had an average preoperative kyphotic angle of 69.6° and who underwent correction using dorsal wiring, wire and rod constructs, or rod and screw constructs. The most significant loss of correction was seen in patients with wire constructs, whereas patients who had the rod and screw constructs maintained their correction. Steinmetz et al.26 reported a mean loss of 2.2° from a mean correction of 20° using ventral instrumentation. Nonetheless, the lordotic curvature was not significantly compromised.

Functional outcomes were significantly improved for patients who underwent correction for kyphosis. Horizontal gaze was uniformly restored in all patients with cervicothoracic kyphosis from ankylosing spondylitis.3,14,16,23,28 Where documented, patients expressed great satisfaction with surgical outcome for compromised horizontal gaze.9,23,28 There was improvement in symptoms and myelopathy as documented by Nurick score outcomes,17,21,29 modified JOA scores,8,17 Odom outcome grading,9,21 and Frankel grade.1 Even when patients were not formally assessed with a standardized assessment tool, surgery was reported to improve symptoms in most patients.18,26 Of note, patients in the series by Herman and Sonntag12 were more likely to report improvement in pain symptoms than improvement in myelopathy.

The overall surgery-related mortality rate was 2.3%. The incidence of major medical complications was 3.3%. Of note, only 5 of the 14 reviewed articles reported major medical complications. It is unclear whether an evaluation for a major medical complication was performed in the remaining studies, and thus, the overall incidence of 3.3% should be interpreted accordingly. Some surgery-related complications were approach-dependent. Dysphagia8,9,16–18,26 and hoarseness12,26 were almost exclusively seen in strategies that incorporated a ventral approach. These symptoms were mostly transient. The most common neurological complications in patients treated by dorsal osteotomies through a modified Simmons technique were C-8 radiculopathy and spinal cord injury.3,14,16,23,28 During closure of the dorsal wedge osteotomy, the C-8 nerve root is vulnerable. In addition, durotomies appeared to be more common in dorsal approaches.1,17,21 All durotomies were successfully managed without residual CSF fistulas. Surgical wound infections had an overall incidence of 3.3%. Hardware failures were more common with ventral approaches, consisting most commonly of graft dislodgment.

Conclusions

The best clinical evidence for outcomes in patients treated for cervical spine deformity comes from retrospective clinical studies. Overall, a dorsal approach with osteotomy or circumferential approach appeared to result in greater deformity correction than a ventral-only approach. Although complications were not insignificant, the majority of patients had improvement in neurological and functional symptoms.

Disclosure

Dr. La Marca is a consultant for Medtronic, Depuy Spine, and Biomet.

Author contributions to the study and manuscript preparation include the following. Conception and design: P Park, F La Marca. Acquisition of data: AB Etame, AC Wang, KD Than. Analysis and interpretation of data: AB Etame, AC Wang, KD Than. Drafting the article: AB Etame, AC Wang, KD Than. Critically revising the article: P Park. Reviewed final version of the manuscript and approved it for submission: P Park, F La Marca. Statistical analysis: AB Etame, AC Wang, KD Than. Study supervision: P Park, F La Marca.

References

  • 1

    Abumi K, , Shono Y, , Taneichi H, , Ito M, & Kaneda K: Correction of cervical kyphosis using pedicle screw fixation systems. Spine (Phila Pa 1976) 24:23892396, 1999

    • Search Google Scholar
    • Export Citation
  • 2

    Albert TJ, & Vacarro A: Postlaminectomy kyphosis. Spine (Phila Pa 1976) 23:27382745, 1998

  • 3

    Belanger TA, , Milam RA IV, , Roh JS, & Bohlman HH: Cervicothoracic extension osteotomy for chin-on-chest deformity in ankylosing spondylitis. J Bone Joint Surg Am 87:17321738, 2005

    • Search Google Scholar
    • Export Citation
  • 4

    Butler JC, & Whitecloud TS III: Postlaminectomy kyphosis. Causes and surgical management. Orthop Clin North Am 23:505511, 1992

  • 5

    Callahan RA, , Johnson RM, , Margolis RN, , Keggi KJ, , Albright JA, & Southwick WO: Cervical facet fusion for control of instability following laminectomy. J Bone Joint Surg Am 59:9911002, 1977

    • Search Google Scholar
    • Export Citation
  • 6

    Cattell HS, & Clark GL Jr: Cervical kyphosis and instability following multiple laminectomies in children. J Bone Joint Surg Am 49:713720, 1967

    • Search Google Scholar
    • Export Citation
  • 7

    Etame AB, , Than KD, , Wang AC, , La Marca F, & Park P: Surgical management of symptomatic cervical or cervicothoracic kyphosis due to ankylosing spondylitis. Spine (Phila Pa 1976) 33:E559564, 2008

    • Search Google Scholar
    • Export Citation
  • 8

    Ferch RD, , Shad A, , Cadoux-Hudson TA, & Teddy PJ: Anterior correction of cervical kyphotic deformity: effects on myelopathy, neck pain, and sagittal alignment. J Neurosurg 100:1 Suppl Spine 1319, 2004

    • Search Google Scholar
    • Export Citation
  • 9

    Gerling MC, & Bohlman HH: Dropped head deformity due to cervical myopathy: surgical treatment outcomes and complications spanning twenty years. Spine (Phila Pa 1976) 33:E739745, 2008

    • Search Google Scholar
    • Export Citation
  • 10

    Heller JG, , Edwards CC II, , Murakami H, & Rodts GE: Laminoplasty versus laminectomy and fusion for multilevel cervical myelopathy: an independent matched cohort analysis. Spine (Phila Pa 1976) 26:13301336, 2001

    • Search Google Scholar
    • Export Citation
  • 11

    Heller JG, , Silcox DH III, & Sutterlin CE III: Complications of posterior cervical plating. Spine (Phila Pa 1976) 20:24422448, 1995

  • 12

    Herman JM, & Sonntag VK: Cervical corpectomy and plate fixation for postlaminectomy kyphosis. J Neurosurg 80:963970, 1994

  • 13

    Ishihara A: [Roentgenographic studies on the normal pattern of the cervical curvature.]. Nippon Seikeigeka Gakkai Zasshi 42:10331044, 1968. (Jpn)

    • Search Google Scholar
    • Export Citation
  • 14

    Langeloo DD, , Journee HL, , Pavlov PW, & de Kleuver M: Cervical osteotomy in ankylosing spondylitis: evaluation of new developments. Eur Spine J 15:493500, 2006

    • Search Google Scholar
    • Export Citation
  • 15

    McAfee PC, , Bohlman HH, , Ducker TB, , Zeidman SM, & Goldstein JA: One-stage anterior cervical decompression and posterior stabilization. A study of one hundred patients with a minimum of two years of follow-up. J Bone Joint Surg Am 77:17911800, 1995

    • Search Google Scholar
    • Export Citation
  • 16

    McMaster MJ: Osteotomy of the cervical spine in ankylosing spondylitis. J Bone Joint Surg Br 79:197203, 1997

  • 17

    Mummaneni PV, , Dhall SS, , Rodts GE, & Haid RW: Circumferential fusion for cervical kyphotic deformity. J Neurosurg Spine 9:515521, 2008

  • 18

    Nottmeier EW, , Deen HG, , Patel N, & Birch B: Cervical kyphotic deformity correction using 360-degree reconstruction. J Spinal Disord Tech 22:385391, 2009

    • Search Google Scholar
    • Export Citation
  • 19

    Nurick S: The natural history and the results of surgical treatment of the spinal cord disorder associated with cervical spondylosis. Brain 95:101108, 1972

    • Search Google Scholar
    • Export Citation
  • 20

    Nurick S: The pathogenesis of the spinal cord disorder associated with cervical spondylosis. Brain 95:87100, 1972

  • 21

    O'Shaughnessy BA, , Liu JC, , Hsieh PC, , Koski TR, , Ganju A, & Ondra SL: Surgical treatment of fixed cervical kyphosis with myelopathy. Spine (Phila Pa 1976) 33:771778, 2008

    • Search Google Scholar
    • Export Citation
  • 22

    Savini R, , Parisini P, & Cervellati S: The surgical treatment of late instability of flexion-rotation injuries in the lower cervical spine. Spine (Phila Pa 1976) 12:178182, 1987

    • Search Google Scholar
    • Export Citation
  • 23

    Simmons ED, , DiStefano RJ, , Zheng Y, & Simmons EH: Thirty-six years experience of cervical extension osteotomy in ankylosing spondylitis: techniques and outcomes. Spine (Phila Pa 1976) 31:30063012, 2006

    • Search Google Scholar
    • Export Citation
  • 24

    Simmons EH: Kyphotic deformity of the spine in ankylosing spondylitis. Clin Orthop Relat Res 128 6577, 1977

  • 25

    Simmons EH: The surgical correction of flexion deformity of the cervical spine in ankylosing spondylitis. Clin Orthop Relat Res 86:132143, 1972

    • Search Google Scholar
    • Export Citation
  • 26

    Steinmetz MP, , Kager CD, & Benzel EC: Ventral correction of postsurgical cervical kyphosis. J Neurosurg 98:1 Suppl 17, 2003

  • 27

    Takeshita K, , Murakami M, , Kobayashi A, & Nakamura C: Relationship between cervical curvature index (Ishihara) and cervical spine angle (C2–7). J Orthop Sci 6:223226, 2001

    • Search Google Scholar
    • Export Citation
  • 28

    Tokala DP, , Lam KS, , Freeman BJ, & Webb JK: C7 decancellisation closing wedge osteotomy for the correction of fixed cervico-thoracic kyphosis. Eur Spine J 16:14711478, 2007

    • Search Google Scholar
    • Export Citation
  • 29

    Zdeblick TA, & Bohlman HH: Cervical kyphosis and myelopathy. Treatment by anterior corpectomy and strut-grafting. J Bone Joint Surg Am 71:170182, 1989

    • Search Google Scholar
    • Export Citation

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Contributor Notes

Address correspondence to: Paul Park, M.D., Department of Neurosurgery, University of Michigan Health System, 1500 East Medical Center Drive, Room 3552, Taubman Center, Ann Arbor, Michigan 48109-5338. email: ppark@umich.edu.
  • View in gallery

    Diagram illustrating CBV angle, which is the angle between lines A and B. In the figure with the flexion deformity (left) the angle is approximately 90°, while in the figure with near-normal alignment (right) the angle is closer to 0°.

  • View in gallery

    Diagram showing Ishihara curvature index. On a lateral radiograph, a vertical line (A) is drawn between the dorso-inferior edges of C-2 and C-7. For a1–a4, perpendicular lines are drawn from line A to the dorsoinferior edge of C-3 to C-6. The lines are measured in millimeters. The Ishihara index = (a1+a2+a3+a4)/A × 100.

  • 1

    Abumi K, , Shono Y, , Taneichi H, , Ito M, & Kaneda K: Correction of cervical kyphosis using pedicle screw fixation systems. Spine (Phila Pa 1976) 24:23892396, 1999

    • Search Google Scholar
    • Export Citation
  • 2

    Albert TJ, & Vacarro A: Postlaminectomy kyphosis. Spine (Phila Pa 1976) 23:27382745, 1998

  • 3

    Belanger TA, , Milam RA IV, , Roh JS, & Bohlman HH: Cervicothoracic extension osteotomy for chin-on-chest deformity in ankylosing spondylitis. J Bone Joint Surg Am 87:17321738, 2005

    • Search Google Scholar
    • Export Citation
  • 4

    Butler JC, & Whitecloud TS III: Postlaminectomy kyphosis. Causes and surgical management. Orthop Clin North Am 23:505511, 1992

  • 5

    Callahan RA, , Johnson RM, , Margolis RN, , Keggi KJ, , Albright JA, & Southwick WO: Cervical facet fusion for control of instability following laminectomy. J Bone Joint Surg Am 59:9911002, 1977

    • Search Google Scholar
    • Export Citation
  • 6

    Cattell HS, & Clark GL Jr: Cervical kyphosis and instability following multiple laminectomies in children. J Bone Joint Surg Am 49:713720, 1967

    • Search Google Scholar
    • Export Citation
  • 7

    Etame AB, , Than KD, , Wang AC, , La Marca F, & Park P: Surgical management of symptomatic cervical or cervicothoracic kyphosis due to ankylosing spondylitis. Spine (Phila Pa 1976) 33:E559564, 2008

    • Search Google Scholar
    • Export Citation
  • 8

    Ferch RD, , Shad A, , Cadoux-Hudson TA, & Teddy PJ: Anterior correction of cervical kyphotic deformity: effects on myelopathy, neck pain, and sagittal alignment. J Neurosurg 100:1 Suppl Spine 1319, 2004

    • Search Google Scholar
    • Export Citation
  • 9

    Gerling MC, & Bohlman HH: Dropped head deformity due to cervical myopathy: surgical treatment outcomes and complications spanning twenty years. Spine (Phila Pa 1976) 33:E739745, 2008

    • Search Google Scholar
    • Export Citation
  • 10

    Heller JG, , Edwards CC II, , Murakami H, & Rodts GE: Laminoplasty versus laminectomy and fusion for multilevel cervical myelopathy: an independent matched cohort analysis. Spine (Phila Pa 1976) 26:13301336, 2001

    • Search Google Scholar
    • Export Citation
  • 11

    Heller JG, , Silcox DH III, & Sutterlin CE III: Complications of posterior cervical plating. Spine (Phila Pa 1976) 20:24422448, 1995

  • 12

    Herman JM, & Sonntag VK: Cervical corpectomy and plate fixation for postlaminectomy kyphosis. J Neurosurg 80:963970, 1994

  • 13

    Ishihara A: [Roentgenographic studies on the normal pattern of the cervical curvature.]. Nippon Seikeigeka Gakkai Zasshi 42:10331044, 1968. (Jpn)

    • Search Google Scholar
    • Export Citation
  • 14

    Langeloo DD, , Journee HL, , Pavlov PW, & de Kleuver M: Cervical osteotomy in ankylosing spondylitis: evaluation of new developments. Eur Spine J 15:493500, 2006

    • Search Google Scholar
    • Export Citation
  • 15

    McAfee PC, , Bohlman HH, , Ducker TB, , Zeidman SM, & Goldstein JA: One-stage anterior cervical decompression and posterior stabilization. A study of one hundred patients with a minimum of two years of follow-up. J Bone Joint Surg Am 77:17911800, 1995

    • Search Google Scholar
    • Export Citation
  • 16

    McMaster MJ: Osteotomy of the cervical spine in ankylosing spondylitis. J Bone Joint Surg Br 79:197203, 1997

  • 17

    Mummaneni PV, , Dhall SS, , Rodts GE, & Haid RW: Circumferential fusion for cervical kyphotic deformity. J Neurosurg Spine 9:515521, 2008

  • 18

    Nottmeier EW, , Deen HG, , Patel N, & Birch B: Cervical kyphotic deformity correction using 360-degree reconstruction. J Spinal Disord Tech 22:385391, 2009

    • Search Google Scholar
    • Export Citation
  • 19

    Nurick S: The natural history and the results of surgical treatment of the spinal cord disorder associated with cervical spondylosis. Brain 95:101108, 1972

    • Search Google Scholar
    • Export Citation
  • 20

    Nurick S: The pathogenesis of the spinal cord disorder associated with cervical spondylosis. Brain 95:87100, 1972

  • 21

    O'Shaughnessy BA, , Liu JC, , Hsieh PC, , Koski TR, , Ganju A, & Ondra SL: Surgical treatment of fixed cervical kyphosis with myelopathy. Spine (Phila Pa 1976) 33:771778, 2008

    • Search Google Scholar
    • Export Citation
  • 22

    Savini R, , Parisini P, & Cervellati S: The surgical treatment of late instability of flexion-rotation injuries in the lower cervical spine. Spine (Phila Pa 1976) 12:178182, 1987

    • Search Google Scholar
    • Export Citation
  • 23

    Simmons ED, , DiStefano RJ, , Zheng Y, & Simmons EH: Thirty-six years experience of cervical extension osteotomy in ankylosing spondylitis: techniques and outcomes. Spine (Phila Pa 1976) 31:30063012, 2006

    • Search Google Scholar
    • Export Citation
  • 24

    Simmons EH: Kyphotic deformity of the spine in ankylosing spondylitis. Clin Orthop Relat Res 128 6577, 1977

  • 25

    Simmons EH: The surgical correction of flexion deformity of the cervical spine in ankylosing spondylitis. Clin Orthop Relat Res 86:132143, 1972

    • Search Google Scholar
    • Export Citation
  • 26

    Steinmetz MP, , Kager CD, & Benzel EC: Ventral correction of postsurgical cervical kyphosis. J Neurosurg 98:1 Suppl 17, 2003

  • 27

    Takeshita K, , Murakami M, , Kobayashi A, & Nakamura C: Relationship between cervical curvature index (Ishihara) and cervical spine angle (C2–7). J Orthop Sci 6:223226, 2001

    • Search Google Scholar
    • Export Citation
  • 28

    Tokala DP, , Lam KS, , Freeman BJ, & Webb JK: C7 decancellisation closing wedge osteotomy for the correction of fixed cervico-thoracic kyphosis. Eur Spine J 16:14711478, 2007

    • Search Google Scholar
    • Export Citation
  • 29

    Zdeblick TA, & Bohlman HH: Cervical kyphosis and myelopathy. Treatment by anterior corpectomy and strut-grafting. J Bone Joint Surg Am 71:170182, 1989

    • Search Google Scholar
    • Export Citation

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