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Cervical discectomy
Spine
Cervical Discectomy A PROSPECTIVE ANALYSIS OF THREE OPERATIVE TECHNIQUES Fremont P. Wirth, M.D.,* Gregory C. Dowd, M.D.,† Herbert F. Sanders, M.D.,* and Carolyn Wirth, B.S.* *Neurological Institute of Savannah and St. Joseph’s Hospital, Savannah, Georgia †Louisiana State University Medical Center, New Orleans, Louisiana
Wirth FP, Dowd GC, Sanders HF, Wirth C. Cervical discectomy. A prospective analysis of three operative techniques. Surg Neurol 2000;53:340 – 8. BACKGROUND
Cervical disc herniation causing neurological compromise is a common affliction. Sophisticated surgical treatments have been developed throughout the twentieth century and are largely successful. Although each procedure has its supporters, it is still unclear if one surgical technique is superior. METHODS
A prospective trial was designed to evaluate the efficacy of three surgical procedures for the treatment of cervical radiculopathy caused by a unilateral acute herniated cervical disc. Patients were randomized to posterior cervical foraminotomy (FOR), and anterior cervical discectomy with (ACDF), and without (ACD) fusion. Perioperative data, office follow-up and long-term follow-up were used to compare the procedures. RESULTS
All of the procedures yielded excellent relief of symptoms and signs postoperatively and during follow-up. Operative time and hospital stay were slightly shorter for ACD compared with ACDF and FOR. Reoperations occurred in all groups but there was a trend for higher recurrence at the same level with FOR and recurrence at other levels with ACDF. CONCLUSION
All three of the procedures were successful for treatment of cervical radiculopathy caused by a herniated cervical disc. Although the numbers in this study were small, none of the procedures could be considered superior to the others. This study suggests that the selection of surgical procedure may reasonably be based on the preference of the surgeon and tailored to the individual patient. © 2000 by Elsevier Science Inc. KEY WORDS
Cervical spine, radiculopathy, discectomy.
Address reprint requests to: Dr. Fremont P. Wirth, Neurological Institute of Savannah, 4 Jackson Blvd., Savannah, GA 31405. Received November 17, 1999; accepted February 18, 2000. 0090-3019/00/$–see front matter PII S0090-3019(00)00201-9
he importance of the cervical spinal cord was recognized by Galen [1] with respect to the poor prognosis of the quadriplegic patient. However, causes of cervical pain and compromise were poorly characterized before the advent of roentgenography. Since the early twentieth century, cervical “arthritis” has been a recognized cause of neck pain. Krause [2] first described the surgical removal of an “enchondroma” in 1907. Further characterization of this entity as a herniated cervical disc led to development of surgical techniques for its treatment [3]. This was initially via a laminectomy due to the successful utility of this approach for the lumbar spine and surgeons’ familiarity [4]. However, it became clear that although some lateral, soft cervical fragments were well treated via the posterior approach, other lesions frustrated surgeons’ efforts [5,6]. Hard osteophytic ridges and midline pathology, difficult to access from a posterior exposure, led to anterior approaches to the cervical spine [5,6]. This was largely successful. As these procedures were technically easy, incurred less blood loss, and were well tolerated, they quickly became the procedures of choice. Due to the amount of disc material removed with the anterior approach, interbody fusion was performed by many [5,6]. Because of donor site morbidity and complications of graft dislodgement and collapse [7], simple anterior discectomy without fusion began to gain favor [8,9]. Surgeons have used case series to argue for the superiority of a certain procedure [6,8,10]. However, due to the variable pathologic diagnoses (osteophyte vs. soft disc herniation, radiculopathy vs. myelopathy) and surgical procedures (posterior vs. anterior) used in these series, few clear-cut recommendations can be made. This has led to a call for careful outcomes studies comparing spe-
T
© 2000 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
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Patient Demographic Profile
Gender (% female) Age (years) Smokers Accidents Worker’s Compensation claims Symptom duration (weeks)
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
59% 43.8 (30–66) 9 (41%) 1 (5%) 3 (14%) 5.5 (1–24)
48% 45.0 (30–67) 15 (60%) 2 (8%) 4 (16%) 7.3 (1–36)
44% 41.7 (28–63) 15 (60%) 2 (8%) 2 (8%) 4.0 (1–20)
cific procedures for the treatment of defined clinical conditions [2,11].
Methods PATIENT POPULATION A randomized, prospective study of patients presenting with cervical radiculopathy caused by a unilateral herniated cervical disc was designed to evaluate the surgical treatment methods. The patient accrual was from 1984 until 1991, inclusive. All patients had single-level disease. Exclusion criteria were signs of myelopathy and additional degenerative changes on plain radiography. Patients with cervical spondylosis were evaluated concurrently and the results are reported elsewhere. Seventyfour patients were recruited and randomized to the three surgical modalities by sealed envelope; however, two patients declined surgical intervention (one ACD and one FOR), yielding 72 surgical patients for analysis. Twenty-two patients underwent cervical foraminotomy, 25 underwent anterior discectomy alone, and 25 underwent anterior discectomy with fusion. SURGICAL TECHNIQUE All procedures were performed by a single surgeon (FPW). The microscope was used in all cases. FOR. Patients were operated in sitting position early and late in the series. Anesthetic management of these patients included an atrial catheter and precordial doppler. However, the middle half were operated in the prone position. A three-point headholder was used for all cases. A midline skin incision was made. Bony removal consisted of a partial hemi-laminectomy of the involved level, foraminotomy with partial facetectomy and removal of free fragments of disc. The disc space itself was not explored. ACD. The patients were positioned supine. Incision was on the right side of the neck at an appropriate skin crease in all cases. Dissection continued
in the usual fashion to the anterior spine. Radiographic confirmation of the correct level was performed in all cases. Discectomy included removal of the posterior longitudinal ligament in all cases. A bilateral anterior foraminotomy was performed. The technique was the same as the ACD except at the end of the procedure, a modified Cloward fusion [12] was performed with a high speed air drill (Midas Rex) and autologous iliac crest bone graft was obtained from side of the patient’s preference. Instrumentation was not used in any case. ACDF.
OUTCOME MEASURES Hospital data was analyzed, including anesthesia time for surgery, length of stay, patient charges, and analgesic medication requirements (injectible and oral). Additionally, data for morbid medical and neurological events were recorded. The neurological exam was compared with the preoperative status on the first post-surgical day and at two months. The patient’s perception of their pain was recorded on the morning following surgery, at the 2-month office visit, and on delayed phone follow-up (average: 60 months). Additionally, return to work was assessed at the second office visit. A grading scheme to compare procedures was used at the 2-month visit. The parameters incorporated were length of hospitalization, radicular pain improvement, and return to work. Fusion was assessed by delayed flexion/extension studies. Subsequent operations were recorded and analyzed.
Results The demographic analysis (Table 1) indicates that the populations undergoing each of the procedures were similar with respect to age (FOR: 43.8, ACD: 45.0, ACDF: 41.7 years), gender (Female; FOR: 59%, ACD: 48%, ACDF: 44%), smoking history (FOR: 41%, ACD: 60%, ACDF: 60%), accidents (FOR: 5%, ACD: 8%, ACDF: 8%), incidence of compensation claims
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Preoperative Neurological Findings
Weakness Numbness Reflex loss Myelopathy
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
9 (41%) 16 (73%) 16 (73%) 0
11 (44%) 21 (84%) 20 (80%) 0
11 (44%) 21 (84%) 19 (76%) 0
(FOR: 14%, ACD: 16%, ACDF: 8%), and duration of symptoms (FOR: 5.5, ACD: 7.3, ACDF: 4.0 weeks). The preoperative neurological findings between groups are presented in Table 2. Note that the prevalence of weakness (FOR: 41%, ACD: 44%, ACDF: 44%), sensory deficit (FOR: 73%, ACD: 84%, ACDF: 84%), and reflex changes (FOR: 73%, ACD: 80%, ACDF: 76%) were similar between groups. Table 3 shows the cervical levels involved and treated surgically. The prevalence of disease at each level was as follows: C3-4 (3%), C4-5 (12%), C5-6 (39%), C6-7 (46%). No patients in this series had involvement at the cervico-thoracic junction. Hospital data were obtained for the length of anesthesia time (FOR: 139 ⫾ 53, ACD: 98 ⫾ 20, ACDF: 120 ⫾ 21 min, p ⬍ 0.005), postoperative analgesic medications required (FOR: 15.9 ⫾ 12.6, ACD: 13.0 ⫾
3
9.2, ACDF: 12.5 ⫾ 50.2, ns), hospital stay (FOR: 4.3 ⫾ 1.9, ACD: 3.9 ⫾ 1.8, ACDF: 4.5 ⫾ 1.6, ns), and hospital charges (ns) (Table 4). Pain improvement (complete relief or partial improvement) was excellent for all groups (100% of patients) on the first postoperative day. Analgesic medication requests were higher in FOR (mean 9.2) when compared with anterior approaches (ACD: 6.0, ACDF: 6.4). This did not achieve statistical significance. Postoperative new weakness (FOR: 14%, ACD: 8%, ACDF: 8%, ns) and new numbness (FOR: 9%, ACD: 8%, ACDF: 4%, ns) were similar between groups. All of these were transient and cleared by the first office visit. No mortality or major morbidity (including infections) was encountered. The 2-month office visit provided data that pain relief, return to work, and relief of preoperative
Operative Level
C3-4 C4-5 C5-6 C6-7 Left side symptoms Right side symptoms (% right side)
4
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
TOTAL (N ⴝ 72)
0 4 5 13 12 10 (45%)
2 2 11 10 2 23 (92%)
0 3 12 10 0 25 (100%)
2 9 28 33 14 58 (81%)
Peri-operative Data
Anesthesia timea (minutes) Hospital stay (days) Charges (⫻ $1000) Analgesic medications (injections plus oral) Pain improvementa (% with complete relief) New weakness New numbness Hoarseness a
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
139 ⫾ 53 4.3 ⫾ 1.9 9.14 15.9 100% (41) 3 (14%) 2 (9%) 0
98 ⫾ 20 3.9 ⫾ 1.8 8.99 13.0 100% (72) 2 (8%) 2 (8%) 0
120 ⫾ 21 4.5 ⫾ 1.6 9.21 12.5 100% (64) 2 (8%) 1 (4%) 0
“Pain improvement” includes both partial and complete resolution of radicular pain. Significance at p ⬍ 0.001.
b
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Office Follow-up (2 Months)
a
Pain improvement (% with complete relief) Persistent neurological deficitb Return to work
FOR
ACD
ACDF
100% (77) 1 (5%) 91%
100% (72) 0 88%
96% (76) 2 (8%) 92%
a
“Pain improvement” includes both partial and complete resolution of radicular pain. All persistent deficits were present on preoperative assessment. All of the new neurological deficits found postoperatively resolved by the first office visit. b
neurological deficits were similar between all groups (Table 5). A grading scheme (Table 9) was constructed based on the method of Lavyne and Bilsky [13] to compare these procedures. Parameters recorded were hospital stay, pain relief at two months, and time of return to work. Possible scores ranged from 3 (worst) to 9 (best). We found the ACD group to have the best score (7.3) followed by FOR (7.1) and ACDF (6.8); however, these were not statistically different (See Table 10 and Fig. 1). Reoperations were recorded (FOR: 27%, ACD: 12%, ACDF: 24%) (Table 6). FOR had the most reoperations at the same level (FOR: 4, ACD: 1, ACDF: 2). ACDF had the most reoperations at other levels (ACDF: 6, FOR: 4, ACD: 3). The recurrences at the same level presented earlier (average: 42 months) than those at other levels (average: 48 months). Fusion was evaluated for the ACD and ACDF
groups (Table 7). The rate of fusion was similar between ACD (82%, 9 of 11 patients at average of 48 months postop) and ACDF (80%, 16 of 20 patients at average of 16 months postop). The patients in the FOR group did not have flexion and extension views for fusion analysis. Delayed follow-up via telephone interview was obtained (FOR: 53, ACD: 56, ACDF: 69 months). The overall pain relief was high among all groups although there was a shift from the high incidence of complete pain relief at the first office visit to reduced but not complete relief of pain at long-term phone follow-up (see Fig. 2). The majority of patients in both groups were working (FOR: 79%, ACD: 92%, ACDF: 81, ns). 100% of patients interviewed at phone follow-up felt that the operation was helpful.
Discussion
Postoperative outcome at two months. This grading scheme combines data on pain relief, resolution of neurological deficits and return to work [13]. There was not a statistical difference between these groups.
1
6
There are many variables to consider regarding the decision to approach the herniated cervical disc via the anterior or posterior route. These depend on patient factors, technical differences between procedures, and surgeon experience and preference. The majority of the pathology that may affect a nerve root is situated anteriorly: disc herniation and osteophyte formation [14]. It is logical to approach these structures with an anterior cervical discectomy (ACD). Although rare, complications from damage to surrounding structures such as the carotid artery, esophagus, trachea, or nerves (sympathetic chain and recurrent laryngeal) may be serious [7,15]. Additionally, foraminal narrowing with
Recurrent Disc Operations
Same level recurrence Other level recurrence Total reoperations
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
4 4 6 (27%)
1 3 3 (12%)
2 6 7 (28%)
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Fusion Analysis (FOR Cases not Analyzed)
MONTHS POST-OP PROCEDURE
FUSED
(AVERAGE)
ACD (n ⫽ 11) ACDF (n ⫽ 20)
9 (82%) 16 (80%)
48 16
recurrent radiculopathy or progressive kyphosis has been attributed to disc space collapse [15]. The addition of a fusion procedure (ACDF) provides support for the anterior disc space and can help avoid the problems associated with disc space collapse [5,6]. However, all of the exposure-related complications still remain. In fact, there is some evidence that the additional length of the procedure and the increased retraction required for graft placement may increase the incidence of local complications [16,17]. Moreover, graft-related complications and donor site morbidity are not insignificant [7,15,18]. The benefit of the posterior approach to the cervical spine is that it avoids the trachea, esophagus, and carotid artery. The nerve root is directly decompressed. Any loose or free disc fragments may be removed. Although the dissection plane through muscle is painful, it is unlikely to result in a recognizable complication. As the disc space has not been transgressed, the partial removal of a single facet does not result in instability. A major drawback of this procedure is that anterior pathology is not directly accessed and osteophytes and medial disc herniations are poorly seen [11,19,20]. The present study analyzed the surgical treatment for a lateral herniated cervical disc via anterior and posterior approaches. Patients with osteophytes, cervical spondylosis, and instability were excluded due to the investigators’ belief that these were better treated with an anterior approach to the cervical spine [10]. This provided a homogeneous group of patients to compare these procedures. Furthermore, all procedures were done by
8
The pain improvement provided by the operative procedure. The results demonstrate the durability of pain relief over time. Note: “pain improvement” includes both complete relief and partial improvement.
2
the same surgeon at one institution, enhancing internal consistency. The results demonstrate that all of the procedures were successful in the treatment of the radiculopathy. The operative time was significantly less (p ⬍ 0.005) for ACD than for ACDF and FOR. The long OR times for the foraminotomy may partly stem from the changes in patient positioning for this technique (sitting-prone-sitting) throughout the study period. The postoperative symptom relief, pain improvement, and requests for analgesic medications were similar between groups. A grading scheme [13] was used to compare the results of these procedures at the two-month office visit (Table 9). This combined the parameters of length of hospital stay, pain relief, and time of return to work. The ACD group had the highest cumulative score, followed by the FOR and the ACDF groups (Table 10 and Fig. 2); however, these differences did not achieve statistical significance. The ACDF group had a significantly lower score on the return to work parameter (p ⬍ 0.05). This difference may be explained by more patients in the ACDF group returning to work later than 10 weeks post-
Telephone Follow-up
PROCEDURE
FOR (N ⴝ 14)
ACD (N ⴝ 13)
ACDF (N ⴝ 16)
Pain improvementa (% complete relief) “Are you working?” (yes) “Was the operation helpful?” (yes) Months
100% (50) 11 (79%) 14 (100%) 53
92% (69) 12 (92%) 13 (100%) 56
100% (44) 13 (81%) 16 (100%) 69
a
“Pain improvement” includes both partial and complete resolution of radicular pain.
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Outcomes Measurement Scheme (Calculated at the 2-Month Office Visit)
SCORE 3 2 1
HOSPITAL STAY
PAIN IMPROVEMENT (AT 2 MONTHS)
⬍3 days 3–5 days ⬎5 days
Complete relief Partial improvement No change or pain worse
RETURN
TO
WORK
By 35 days Between 36 and 70 days After 71 days
Score range: 3 to 9.
operatively as compared to ACD and FOR. Statistical chance may also account for this discrepancy. In terms of recurrent symptoms necessitating further surgery, ACD was lower than ACDF or FOR (Table 6). The FOR group had more recurrent disc pathology at the same level. The ACDF group had few recurrences at the same level but an increased number at neighboring levels. This supports the assertion that ACDF may accelerate cervical spondylosis at adjacent levels, perhaps by rigidly fixing the motion segment and transferring additional load to neighboring segments [20]. However, these differences represented trends only and did not reach statistical significance. Long-term relief of symptoms (approximately 5 years) demonstrates the durability of these procedures (Fig. 2). 97% of the patients contacted had maintained an improvement in pain status. All of these patients felt that the operation had been helpful. However, only 60% of the study patients could be reached for follow-up, which may affect the results. The outcome of this study compares favorably with other randomized prospective trials of cervical discectomy [16,17,21,22]. These studies all compared anterior cervical discectomy alone with discectomy and a fusion procedure. All of these studies found similar clinical results between the two groups. This was true regardless of whether the interbody graft for ACDF was autograft [16,17,22] or allograft [21]. The rate of return to work was similar between ACD and ACDF groups [17,21]. The presence of a successful fusion did not influence the clinical results [17]. A slight kyphosis at the oper-
10
FOR ACD ACDF
ated level was occasionally seen on follow-up radiography. This was found more frequently in the ACD group (62–70%) compared with the ACDF group (16 – 40%) [16,22]. The clinical significance of this finding is unclear. Comparison between the anterior and posterior approaches reveals a greater difference of opinion than difference in outcome. The surgical results have been largely successful irrespective of the technique of neural decompression and discectomy [10]. Herkowitz et al. [11] performed a randomized, prospective comparison of ACDF and laminotomyforaminotomy for laterally herniated cervical disks. In this small study of 33 patients, they found “excellent-good” results at 4.2 years in 94% of ACDF patients and 75% of posteriorly treated patients. They noted that both provided satisfactory outcome although there was a trend toward better results with the anterior approach.
Conclusion This prospective, randomized study compared the three procedures commonly utilized for the surgical treatment of cervical radiculopathy caused by a unilateral herniated nucleus pulposus. All three yielded excellent relief of subjective symptoms and objective signs of this condition. There was a trend toward reduced operative time and hospital stay and reduced reoperations with the ACD technique. However, all of the procedures were efficacious and may be reasonably employed based on the surgeon’s preference and individual patient factors.
Outcome Comparison Between Surgical Procedures. (see Table 9 for scoring scheme)
HOSPITAL STAY
PAIN RELIEF
RETURN TO WORKA
TOTAL
1.9 2.1 1.9
2.7 2.5 2.8
2.5 2.7 2.1
7.1 ⫾ 1.0 7.3 ⫾ 1.3 6.8 ⫾ 1.4
Rate of return to work was statistically different. ACDF patients scored lower than ACD and FOR, p ⬍ 0.05).
a
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REFERENCES
randomized study of anterior single-level cervical disc operations with long-term follow-up: surgical fusion is unnecessary. Neurosurgery 1998;43:51–5.
1. Voorhies RM. Managing the more common cervical disorders. IM 1996;17:18 – 41. 2. Davis RA. Long term outcome of 170 surgically treated herniated discs causing cervical radiculopathy. Surg Neurol 1996;46:523–33. 3. Dandy WE. Loose cartilage from intervertebral disk simulating tumor of the spinal cord. Arch Surg 1929; 19:660 –72. 4. Mixter WJ, Barr JS. Rupture of the intervertebral disc with involvement of the spinal canal. NEJM 1934;211: 210 –5. 5. Robinson RA, Smith GW. Anterolateral cervical disc removal and interbody fusion for cervical disc syndrome. (Abstract) Johns Hopk Hosp Bull 1955;96: 223– 4. 6. Cloward RB. The anterior approach for removal of ruptured cervical disks. J Neurosurg 1958;15:602–17. 7. Flynn TB. Neurologic complications of anterior cervical interbody fusion. Spine 1982;7:536 –9. 8. Hirsch C. Cervical disk rupture: diagnosis and therapy. Acta Orthop Scand 1960;30:172– 86. 9. Murphey MG, Gado M. Anterior cervical discectomy without interbody bone graft. J Neurosurg 1972;37: 71– 4. 10. Dillin W, Booth R, Cuckler J, Balderston R, Simeone F, Rothman R. Cervical radiculopathy: a review. 1986; 11:988 –91. 11. Herkowitz HN, Kurz LT, Overholt DP. Surgical management of cervical soft disc herniation: a comparison between the anterior and posterior approach. Spine 1990;15:1026 –30. 12. Wirth FP. High speed drills. In: Wilkins RH, Rengarchary SS (eds). Neurosurgery. New York: McGraw– Hill, 1996:591– 4. 13. Lavyne MH, Bilsky MH. Epidural steroids, postoperative morbidity, and recovery in patients undergoing microsurgical lumbar discectomy. J Neurosurg 1992; 77:90 –5. 14. Brain WR, Northfield D, Wilkinson M. The neurologic manifestations of cervical spondylosis. Brain 1952;75: 187–225. 15. Bertalanffy H, Eggert HR. Complications of anterior cervical discectomy without fusion in 450 consecutive patients. Acta Neurochir 1989;99:41–50. 16. Martins AN. Anterior cervical discectomy with and without interbody bone graft. J Neurosurg 1976;44: 290 –5. 17. Dowd GC, Wirth FP. Anterior Cervical Discectomy: is Fusion Necessary? J Neurosurg (Spine 1) 1999;90:8 – 12. 18. Connolly ES, Seymour RJ, Adams JE. Clinical evaluation of anterior cervical fusion for degenerative cervical disc disease. J Neurosurg 1965;23:431–7. 19. Ducker TB, Zeidman SM. The posterior approach for cervical radiculopathy. Neurosurg Clin N. A. 1993;4: 61–74. 20. Simeone FA. Posterior discectomy for soft cervical disc. In: Al–Mefty O, Origitano TC, Harkey HL (eds). Controversies in Neurosurgery. New York: Thieme, 1995:227– 8. 21. Rosenorn J, Hansen EB, Rosenorn MA. Anterior cervical discectomy with and without fusion. J Neurosurg 1983;59:252–5. 22. Savolainen S, Rinne J, Hernesniemi J. A prospective
COMMENTARY
This is a very well-written paper presenting for the first time a randomized study comparing three different surgical approaches. We all know that pain relief can be obtained in nearly all cases of radiculopathy due to lateral cervical disc herniation, no matter what surgical approach is used. But what is strange, at least as far as my experience and the data in the literature are concerned, is the assertion that the results after anterior diskectomy without fusion were as good as after an anterior approach with fusion. Moreover, I must ask myself how much reliability can be given to a series of 72 patients (22 FOR, 25 ACD, and 25 ACDF), considering that only 60% of them could be followed long-term. In some of these cases, the duration of symptoms before operation was only 1 week. How many of these patients might have obtained long-lasting relief from their symptoms without surgery? Would the authors be able to duplicate these results with a large number of patients who were refractory to conservative treatment? I can’t help saying that, in my opinion, in cases of lateral discal hernia impinging on the foramen to any degree, the posterior approach, as advocated by Scoville and Frykholm, is mandatory. I see no reason for performing an anterior approach (with graft!) in such cases. In my hands, at least (more than 400 anterior operations for medial and mediolateral discs or spondylosis, and 95 posterior operations for lateral discs), the anterior approach requires more time and sometimes leads to complications, such as dysphonia and graft displacement, which do not occur when the posterior approach is used. I have also seen, though rarely, cases in which a fragment of the disc was left in the foramen after an anterior diskectomy, which had to be removed via the posterior route in a second operation. Carlo A. Pagni Clinica Neurochirurgica Universita ` degli Study di Torino Turin, Italy This is a carefully done prospective, randomized study which compares outcome following either an anterior cervical diskectomy; anterior cervical diskectomy and interbody fusion; or cervical laminotomy, medial facetectomy, and foraminotomy. The
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study is important because rarely are the three procedures compared in this manner. It is of interest that the results indicate that the outcome of each of the three operations was similar. The study was not designed to answer the question of what factors related to the patient are appropriate to consider when advising a particular operation. In light of the findings, though, that would seem to be a worthwhile question to address in the future.
and currently employed with extravagance beyond reason. Assuming Wirth and colleagues will continue to use their foraminotomy approach for some patients, I would suggest that the plane of dissection not be undertaken “through the muscle” but with a slightly longer incision such as that which I have repeatedly advised [2,3], avoiding muscle damage, postoperative pain, and even allowing for ambulatory surgery as advocated by Tomaras et al. [4].
Franklin C. Wagner, Jr., M.D. Department of Neurosurgery University of Illinois at Chicago Chicago, Illinois
Charles A. Fager, M.D. Neurosurgeon Burlington, Massachusetts
Dr. Wirth et al. have confirmed the proposition that a well-designed study of a small number of patients can be meaningful in clarifying the conflicting surgical opinions that have existed since the introduction of anterior cervical diskectomy. My own bias has always been in favor of the posterolateral approach with foraminotomy, which has through long years of experience proved to be among the most gratifying operations in neurosurgery. I have now had the pleasant experience of seeing patients ranging up to 35 years after surgery who have not only had an excellent long-term result, but also no disturbance in the architecture of the cervical spine beyond that of the normal aging process. Nor have I seen recurrence after this approach as reported by the authors, though there have been a small number of patients in whom a retained fragment of disc required secondary surgery. The fact that the authors’ results have been just as good with anterior operations quite pointedly argues to the importance of the indications for surgery, rather than the approach that they wisely undertook specifically for single-level lateral disc herniation with radiculopathy. The prospective determination to select such candidates virtually rules out the failures so commonly seen with multiple-level diskectomy and fusion for neck pain alone, headache, post-traumatic soft tissue injury, and degenerative changes that are not clearly symptomatic. It is difficult to argue against such success of anterior diskectomy, yet it also seems clear from this study that fusion need not be done and its complications can be avoided. Of even greater significance is the fact that the authors achieved excellent results without the unnecessary placement of hardware advocated by Caspar [1] and others,
REFERENCES 1. Fager CA, Wirth FP, Yarzagaray L, Wissinger JP, Caspar W. Extruded cervical disc. Surg Neurol 1996;45:512– 6. 2. Fager CA. The atlas of spinal surgery. Philadelphia: Lea & Febiger, 1989. 3. Fager CA. Role of laminotomy in cervical disc herniation. Mt. Sinai Bull 1994;61:228 –32. 4. Tomaras CR, Blacklock JB, Parker WD, Harper RL. Outpatient surgical treatment of cervical radiculopathy. J Neurosurg 1997;87:41–3.
This paper by Wirth et al. demonstrates that good results can be obtained for a ruptured cervical disc using any one of three standard procedures— cervical laminectomy and foraminotomy (FOR), anterior cervical diskectomy (ACD) and ACD with fusion (ACDF). Simple FOR did well, but generally had more postoperative pain. ACD had a higher incidence of kyphosis and ACDF had a longer time to return to work. The paper does not specify the reason for the delay in returning to work. ACDF was carried out using iliac crest homograft, and the attendant hip pain may be the problem. The use of allografts would obviate this problem. More recently, many neurosurgeons are using titanium plates with the idea that it decreases pain, returns the patient to work sooner, and reduces the need for a collar. As far as I know, there is no published report of a study comparing ACDF using allograft without and with plating, so we do not know if plating is better. In the last 2 years, I have routinely carried out ACDF using a fibular allograft for cervical ruptured disc—no plate. Each patient gets a soft collar that may be discarded when the patient feels like it (usually one week or less). The patient can also return to work when comfortable, usually 2 to 4 weeks unless they do heavy labor. I doubt if having a plate would be better. Hopefully, some group will carry
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out a controlled study. It should result in a significant decrease in cost. Harold D. Portnoy, M.D. Neurosurgeon Pontiac, Michigan Dr. Wirth has reported a prospective series evaluating three common methods for the management of a unilateral monoradicular syndrome, secondary to a cervical disc herniation. Even though the follow-up period is short, Dr. Wirth has been able to follow his patients for 5 years, and has sufficient information available to support his conclusion. Of particular interest is the reported fusion rate of 82% after anterior cervical diskectomy and 80% after anterior cervical diskectomy with graft. This supports my personal impression that a graft is not necessary for a successful outcome. The interested reader should review the report by Drs. Dowd and Wirth [1], wherein a similar finding was reported with the treatment of cervical spondylosis with as-
sociated neurologic deficit. Fusion with a graft was found to be unnecessary for a successful outcome. The incidence of postoperative neurologic deficit does not vary significantly between the three treatment groups, and it is important to note that the deficit cleared within 2 months after the operative procedure. Perhaps the initial euphoria of having survived an operative procedure somewhat clouds the patient’s judgement regarding pain relief. Symptomatic relief was not as universally reported at the 2-month interval, but overall, the reported incidence of satisfactory symptomatic relief supports the premise that surgical management of a unilateral monoradicular syndrome secondary to a cervical disc herniation is the treatment of choice, and remains the gold standard against which nonsurgical therapies should be compared. Harry O. Cole, M.D. Neurosurgeon Chesterfield, Missouri
Cervical Discectomy A PROSPECTIVE ANALYSIS OF THREE OPERATIVE TECHNIQUES Fremont P. Wirth, M.D.,* Gregory C. Dowd, M.D.,† Herbert F. Sanders, M.D.,* and Carolyn Wirth, B.S.* *Neurological Institute of Savannah and St. Joseph’s Hospital, Savannah, Georgia †Louisiana State University Medical Center, New Orleans, Louisiana
Wirth FP, Dowd GC, Sanders HF, Wirth C. Cervical discectomy. A prospective analysis of three operative techniques. Surg Neurol 2000;53:340 – 8. BACKGROUND
Cervical disc herniation causing neurological compromise is a common affliction. Sophisticated surgical treatments have been developed throughout the twentieth century and are largely successful. Although each procedure has its supporters, it is still unclear if one surgical technique is superior. METHODS
A prospective trial was designed to evaluate the efficacy of three surgical procedures for the treatment of cervical radiculopathy caused by a unilateral acute herniated cervical disc. Patients were randomized to posterior cervical foraminotomy (FOR), and anterior cervical discectomy with (ACDF), and without (ACD) fusion. Perioperative data, office follow-up and long-term follow-up were used to compare the procedures. RESULTS
All of the procedures yielded excellent relief of symptoms and signs postoperatively and during follow-up. Operative time and hospital stay were slightly shorter for ACD compared with ACDF and FOR. Reoperations occurred in all groups but there was a trend for higher recurrence at the same level with FOR and recurrence at other levels with ACDF. CONCLUSION
All three of the procedures were successful for treatment of cervical radiculopathy caused by a herniated cervical disc. Although the numbers in this study were small, none of the procedures could be considered superior to the others. This study suggests that the selection of surgical procedure may reasonably be based on the preference of the surgeon and tailored to the individual patient. © 2000 by Elsevier Science Inc. KEY WORDS
Cervical spine, radiculopathy, discectomy.
Address reprint requests to: Dr. Fremont P. Wirth, Neurological Institute of Savannah, 4 Jackson Blvd., Savannah, GA 31405. Received November 17, 1999; accepted February 18, 2000. 0090-3019/00/$–see front matter PII S0090-3019(00)00201-9
he importance of the cervical spinal cord was recognized by Galen [1] with respect to the poor prognosis of the quadriplegic patient. However, causes of cervical pain and compromise were poorly characterized before the advent of roentgenography. Since the early twentieth century, cervical “arthritis” has been a recognized cause of neck pain. Krause [2] first described the surgical removal of an “enchondroma” in 1907. Further characterization of this entity as a herniated cervical disc led to development of surgical techniques for its treatment [3]. This was initially via a laminectomy due to the successful utility of this approach for the lumbar spine and surgeons’ familiarity [4]. However, it became clear that although some lateral, soft cervical fragments were well treated via the posterior approach, other lesions frustrated surgeons’ efforts [5,6]. Hard osteophytic ridges and midline pathology, difficult to access from a posterior exposure, led to anterior approaches to the cervical spine [5,6]. This was largely successful. As these procedures were technically easy, incurred less blood loss, and were well tolerated, they quickly became the procedures of choice. Due to the amount of disc material removed with the anterior approach, interbody fusion was performed by many [5,6]. Because of donor site morbidity and complications of graft dislodgement and collapse [7], simple anterior discectomy without fusion began to gain favor [8,9]. Surgeons have used case series to argue for the superiority of a certain procedure [6,8,10]. However, due to the variable pathologic diagnoses (osteophyte vs. soft disc herniation, radiculopathy vs. myelopathy) and surgical procedures (posterior vs. anterior) used in these series, few clear-cut recommendations can be made. This has led to a call for careful outcomes studies comparing spe-
T
© 2000 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
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Patient Demographic Profile
Gender (% female) Age (years) Smokers Accidents Worker’s Compensation claims Symptom duration (weeks)
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
59% 43.8 (30–66) 9 (41%) 1 (5%) 3 (14%) 5.5 (1–24)
48% 45.0 (30–67) 15 (60%) 2 (8%) 4 (16%) 7.3 (1–36)
44% 41.7 (28–63) 15 (60%) 2 (8%) 2 (8%) 4.0 (1–20)
cific procedures for the treatment of defined clinical conditions [2,11].
Methods PATIENT POPULATION A randomized, prospective study of patients presenting with cervical radiculopathy caused by a unilateral herniated cervical disc was designed to evaluate the surgical treatment methods. The patient accrual was from 1984 until 1991, inclusive. All patients had single-level disease. Exclusion criteria were signs of myelopathy and additional degenerative changes on plain radiography. Patients with cervical spondylosis were evaluated concurrently and the results are reported elsewhere. Seventyfour patients were recruited and randomized to the three surgical modalities by sealed envelope; however, two patients declined surgical intervention (one ACD and one FOR), yielding 72 surgical patients for analysis. Twenty-two patients underwent cervical foraminotomy, 25 underwent anterior discectomy alone, and 25 underwent anterior discectomy with fusion. SURGICAL TECHNIQUE All procedures were performed by a single surgeon (FPW). The microscope was used in all cases. FOR. Patients were operated in sitting position early and late in the series. Anesthetic management of these patients included an atrial catheter and precordial doppler. However, the middle half were operated in the prone position. A three-point headholder was used for all cases. A midline skin incision was made. Bony removal consisted of a partial hemi-laminectomy of the involved level, foraminotomy with partial facetectomy and removal of free fragments of disc. The disc space itself was not explored. ACD. The patients were positioned supine. Incision was on the right side of the neck at an appropriate skin crease in all cases. Dissection continued
in the usual fashion to the anterior spine. Radiographic confirmation of the correct level was performed in all cases. Discectomy included removal of the posterior longitudinal ligament in all cases. A bilateral anterior foraminotomy was performed. The technique was the same as the ACD except at the end of the procedure, a modified Cloward fusion [12] was performed with a high speed air drill (Midas Rex) and autologous iliac crest bone graft was obtained from side of the patient’s preference. Instrumentation was not used in any case. ACDF.
OUTCOME MEASURES Hospital data was analyzed, including anesthesia time for surgery, length of stay, patient charges, and analgesic medication requirements (injectible and oral). Additionally, data for morbid medical and neurological events were recorded. The neurological exam was compared with the preoperative status on the first post-surgical day and at two months. The patient’s perception of their pain was recorded on the morning following surgery, at the 2-month office visit, and on delayed phone follow-up (average: 60 months). Additionally, return to work was assessed at the second office visit. A grading scheme to compare procedures was used at the 2-month visit. The parameters incorporated were length of hospitalization, radicular pain improvement, and return to work. Fusion was assessed by delayed flexion/extension studies. Subsequent operations were recorded and analyzed.
Results The demographic analysis (Table 1) indicates that the populations undergoing each of the procedures were similar with respect to age (FOR: 43.8, ACD: 45.0, ACDF: 41.7 years), gender (Female; FOR: 59%, ACD: 48%, ACDF: 44%), smoking history (FOR: 41%, ACD: 60%, ACDF: 60%), accidents (FOR: 5%, ACD: 8%, ACDF: 8%), incidence of compensation claims
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Preoperative Neurological Findings
Weakness Numbness Reflex loss Myelopathy
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
9 (41%) 16 (73%) 16 (73%) 0
11 (44%) 21 (84%) 20 (80%) 0
11 (44%) 21 (84%) 19 (76%) 0
(FOR: 14%, ACD: 16%, ACDF: 8%), and duration of symptoms (FOR: 5.5, ACD: 7.3, ACDF: 4.0 weeks). The preoperative neurological findings between groups are presented in Table 2. Note that the prevalence of weakness (FOR: 41%, ACD: 44%, ACDF: 44%), sensory deficit (FOR: 73%, ACD: 84%, ACDF: 84%), and reflex changes (FOR: 73%, ACD: 80%, ACDF: 76%) were similar between groups. Table 3 shows the cervical levels involved and treated surgically. The prevalence of disease at each level was as follows: C3-4 (3%), C4-5 (12%), C5-6 (39%), C6-7 (46%). No patients in this series had involvement at the cervico-thoracic junction. Hospital data were obtained for the length of anesthesia time (FOR: 139 ⫾ 53, ACD: 98 ⫾ 20, ACDF: 120 ⫾ 21 min, p ⬍ 0.005), postoperative analgesic medications required (FOR: 15.9 ⫾ 12.6, ACD: 13.0 ⫾
3
9.2, ACDF: 12.5 ⫾ 50.2, ns), hospital stay (FOR: 4.3 ⫾ 1.9, ACD: 3.9 ⫾ 1.8, ACDF: 4.5 ⫾ 1.6, ns), and hospital charges (ns) (Table 4). Pain improvement (complete relief or partial improvement) was excellent for all groups (100% of patients) on the first postoperative day. Analgesic medication requests were higher in FOR (mean 9.2) when compared with anterior approaches (ACD: 6.0, ACDF: 6.4). This did not achieve statistical significance. Postoperative new weakness (FOR: 14%, ACD: 8%, ACDF: 8%, ns) and new numbness (FOR: 9%, ACD: 8%, ACDF: 4%, ns) were similar between groups. All of these were transient and cleared by the first office visit. No mortality or major morbidity (including infections) was encountered. The 2-month office visit provided data that pain relief, return to work, and relief of preoperative
Operative Level
C3-4 C4-5 C5-6 C6-7 Left side symptoms Right side symptoms (% right side)
4
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
TOTAL (N ⴝ 72)
0 4 5 13 12 10 (45%)
2 2 11 10 2 23 (92%)
0 3 12 10 0 25 (100%)
2 9 28 33 14 58 (81%)
Peri-operative Data
Anesthesia timea (minutes) Hospital stay (days) Charges (⫻ $1000) Analgesic medications (injections plus oral) Pain improvementa (% with complete relief) New weakness New numbness Hoarseness a
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
139 ⫾ 53 4.3 ⫾ 1.9 9.14 15.9 100% (41) 3 (14%) 2 (9%) 0
98 ⫾ 20 3.9 ⫾ 1.8 8.99 13.0 100% (72) 2 (8%) 2 (8%) 0
120 ⫾ 21 4.5 ⫾ 1.6 9.21 12.5 100% (64) 2 (8%) 1 (4%) 0
“Pain improvement” includes both partial and complete resolution of radicular pain. Significance at p ⬍ 0.001.
b
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Office Follow-up (2 Months)
a
Pain improvement (% with complete relief) Persistent neurological deficitb Return to work
FOR
ACD
ACDF
100% (77) 1 (5%) 91%
100% (72) 0 88%
96% (76) 2 (8%) 92%
a
“Pain improvement” includes both partial and complete resolution of radicular pain. All persistent deficits were present on preoperative assessment. All of the new neurological deficits found postoperatively resolved by the first office visit. b
neurological deficits were similar between all groups (Table 5). A grading scheme (Table 9) was constructed based on the method of Lavyne and Bilsky [13] to compare these procedures. Parameters recorded were hospital stay, pain relief at two months, and time of return to work. Possible scores ranged from 3 (worst) to 9 (best). We found the ACD group to have the best score (7.3) followed by FOR (7.1) and ACDF (6.8); however, these were not statistically different (See Table 10 and Fig. 1). Reoperations were recorded (FOR: 27%, ACD: 12%, ACDF: 24%) (Table 6). FOR had the most reoperations at the same level (FOR: 4, ACD: 1, ACDF: 2). ACDF had the most reoperations at other levels (ACDF: 6, FOR: 4, ACD: 3). The recurrences at the same level presented earlier (average: 42 months) than those at other levels (average: 48 months). Fusion was evaluated for the ACD and ACDF
groups (Table 7). The rate of fusion was similar between ACD (82%, 9 of 11 patients at average of 48 months postop) and ACDF (80%, 16 of 20 patients at average of 16 months postop). The patients in the FOR group did not have flexion and extension views for fusion analysis. Delayed follow-up via telephone interview was obtained (FOR: 53, ACD: 56, ACDF: 69 months). The overall pain relief was high among all groups although there was a shift from the high incidence of complete pain relief at the first office visit to reduced but not complete relief of pain at long-term phone follow-up (see Fig. 2). The majority of patients in both groups were working (FOR: 79%, ACD: 92%, ACDF: 81, ns). 100% of patients interviewed at phone follow-up felt that the operation was helpful.
Discussion
Postoperative outcome at two months. This grading scheme combines data on pain relief, resolution of neurological deficits and return to work [13]. There was not a statistical difference between these groups.
1
6
There are many variables to consider regarding the decision to approach the herniated cervical disc via the anterior or posterior route. These depend on patient factors, technical differences between procedures, and surgeon experience and preference. The majority of the pathology that may affect a nerve root is situated anteriorly: disc herniation and osteophyte formation [14]. It is logical to approach these structures with an anterior cervical discectomy (ACD). Although rare, complications from damage to surrounding structures such as the carotid artery, esophagus, trachea, or nerves (sympathetic chain and recurrent laryngeal) may be serious [7,15]. Additionally, foraminal narrowing with
Recurrent Disc Operations
Same level recurrence Other level recurrence Total reoperations
FOR (N ⴝ 22)
ACD (N ⴝ 25)
ACDF (N ⴝ 25)
4 4 6 (27%)
1 3 3 (12%)
2 6 7 (28%)
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Fusion Analysis (FOR Cases not Analyzed)
MONTHS POST-OP PROCEDURE
FUSED
(AVERAGE)
ACD (n ⫽ 11) ACDF (n ⫽ 20)
9 (82%) 16 (80%)
48 16
recurrent radiculopathy or progressive kyphosis has been attributed to disc space collapse [15]. The addition of a fusion procedure (ACDF) provides support for the anterior disc space and can help avoid the problems associated with disc space collapse [5,6]. However, all of the exposure-related complications still remain. In fact, there is some evidence that the additional length of the procedure and the increased retraction required for graft placement may increase the incidence of local complications [16,17]. Moreover, graft-related complications and donor site morbidity are not insignificant [7,15,18]. The benefit of the posterior approach to the cervical spine is that it avoids the trachea, esophagus, and carotid artery. The nerve root is directly decompressed. Any loose or free disc fragments may be removed. Although the dissection plane through muscle is painful, it is unlikely to result in a recognizable complication. As the disc space has not been transgressed, the partial removal of a single facet does not result in instability. A major drawback of this procedure is that anterior pathology is not directly accessed and osteophytes and medial disc herniations are poorly seen [11,19,20]. The present study analyzed the surgical treatment for a lateral herniated cervical disc via anterior and posterior approaches. Patients with osteophytes, cervical spondylosis, and instability were excluded due to the investigators’ belief that these were better treated with an anterior approach to the cervical spine [10]. This provided a homogeneous group of patients to compare these procedures. Furthermore, all procedures were done by
8
The pain improvement provided by the operative procedure. The results demonstrate the durability of pain relief over time. Note: “pain improvement” includes both complete relief and partial improvement.
2
the same surgeon at one institution, enhancing internal consistency. The results demonstrate that all of the procedures were successful in the treatment of the radiculopathy. The operative time was significantly less (p ⬍ 0.005) for ACD than for ACDF and FOR. The long OR times for the foraminotomy may partly stem from the changes in patient positioning for this technique (sitting-prone-sitting) throughout the study period. The postoperative symptom relief, pain improvement, and requests for analgesic medications were similar between groups. A grading scheme [13] was used to compare the results of these procedures at the two-month office visit (Table 9). This combined the parameters of length of hospital stay, pain relief, and time of return to work. The ACD group had the highest cumulative score, followed by the FOR and the ACDF groups (Table 10 and Fig. 2); however, these differences did not achieve statistical significance. The ACDF group had a significantly lower score on the return to work parameter (p ⬍ 0.05). This difference may be explained by more patients in the ACDF group returning to work later than 10 weeks post-
Telephone Follow-up
PROCEDURE
FOR (N ⴝ 14)
ACD (N ⴝ 13)
ACDF (N ⴝ 16)
Pain improvementa (% complete relief) “Are you working?” (yes) “Was the operation helpful?” (yes) Months
100% (50) 11 (79%) 14 (100%) 53
92% (69) 12 (92%) 13 (100%) 56
100% (44) 13 (81%) 16 (100%) 69
a
“Pain improvement” includes both partial and complete resolution of radicular pain.
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Outcomes Measurement Scheme (Calculated at the 2-Month Office Visit)
SCORE 3 2 1
HOSPITAL STAY
PAIN IMPROVEMENT (AT 2 MONTHS)
⬍3 days 3–5 days ⬎5 days
Complete relief Partial improvement No change or pain worse
RETURN
TO
WORK
By 35 days Between 36 and 70 days After 71 days
Score range: 3 to 9.
operatively as compared to ACD and FOR. Statistical chance may also account for this discrepancy. In terms of recurrent symptoms necessitating further surgery, ACD was lower than ACDF or FOR (Table 6). The FOR group had more recurrent disc pathology at the same level. The ACDF group had few recurrences at the same level but an increased number at neighboring levels. This supports the assertion that ACDF may accelerate cervical spondylosis at adjacent levels, perhaps by rigidly fixing the motion segment and transferring additional load to neighboring segments [20]. However, these differences represented trends only and did not reach statistical significance. Long-term relief of symptoms (approximately 5 years) demonstrates the durability of these procedures (Fig. 2). 97% of the patients contacted had maintained an improvement in pain status. All of these patients felt that the operation had been helpful. However, only 60% of the study patients could be reached for follow-up, which may affect the results. The outcome of this study compares favorably with other randomized prospective trials of cervical discectomy [16,17,21,22]. These studies all compared anterior cervical discectomy alone with discectomy and a fusion procedure. All of these studies found similar clinical results between the two groups. This was true regardless of whether the interbody graft for ACDF was autograft [16,17,22] or allograft [21]. The rate of return to work was similar between ACD and ACDF groups [17,21]. The presence of a successful fusion did not influence the clinical results [17]. A slight kyphosis at the oper-
10
FOR ACD ACDF
ated level was occasionally seen on follow-up radiography. This was found more frequently in the ACD group (62–70%) compared with the ACDF group (16 – 40%) [16,22]. The clinical significance of this finding is unclear. Comparison between the anterior and posterior approaches reveals a greater difference of opinion than difference in outcome. The surgical results have been largely successful irrespective of the technique of neural decompression and discectomy [10]. Herkowitz et al. [11] performed a randomized, prospective comparison of ACDF and laminotomyforaminotomy for laterally herniated cervical disks. In this small study of 33 patients, they found “excellent-good” results at 4.2 years in 94% of ACDF patients and 75% of posteriorly treated patients. They noted that both provided satisfactory outcome although there was a trend toward better results with the anterior approach.
Conclusion This prospective, randomized study compared the three procedures commonly utilized for the surgical treatment of cervical radiculopathy caused by a unilateral herniated nucleus pulposus. All three yielded excellent relief of subjective symptoms and objective signs of this condition. There was a trend toward reduced operative time and hospital stay and reduced reoperations with the ACD technique. However, all of the procedures were efficacious and may be reasonably employed based on the surgeon’s preference and individual patient factors.
Outcome Comparison Between Surgical Procedures. (see Table 9 for scoring scheme)
HOSPITAL STAY
PAIN RELIEF
RETURN TO WORKA
TOTAL
1.9 2.1 1.9
2.7 2.5 2.8
2.5 2.7 2.1
7.1 ⫾ 1.0 7.3 ⫾ 1.3 6.8 ⫾ 1.4
Rate of return to work was statistically different. ACDF patients scored lower than ACD and FOR, p ⬍ 0.05).
a
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REFERENCES
randomized study of anterior single-level cervical disc operations with long-term follow-up: surgical fusion is unnecessary. Neurosurgery 1998;43:51–5.
1. Voorhies RM. Managing the more common cervical disorders. IM 1996;17:18 – 41. 2. Davis RA. Long term outcome of 170 surgically treated herniated discs causing cervical radiculopathy. Surg Neurol 1996;46:523–33. 3. Dandy WE. Loose cartilage from intervertebral disk simulating tumor of the spinal cord. Arch Surg 1929; 19:660 –72. 4. Mixter WJ, Barr JS. Rupture of the intervertebral disc with involvement of the spinal canal. NEJM 1934;211: 210 –5. 5. Robinson RA, Smith GW. Anterolateral cervical disc removal and interbody fusion for cervical disc syndrome. (Abstract) Johns Hopk Hosp Bull 1955;96: 223– 4. 6. Cloward RB. The anterior approach for removal of ruptured cervical disks. J Neurosurg 1958;15:602–17. 7. Flynn TB. Neurologic complications of anterior cervical interbody fusion. Spine 1982;7:536 –9. 8. Hirsch C. Cervical disk rupture: diagnosis and therapy. Acta Orthop Scand 1960;30:172– 86. 9. Murphey MG, Gado M. Anterior cervical discectomy without interbody bone graft. J Neurosurg 1972;37: 71– 4. 10. Dillin W, Booth R, Cuckler J, Balderston R, Simeone F, Rothman R. Cervical radiculopathy: a review. 1986; 11:988 –91. 11. Herkowitz HN, Kurz LT, Overholt DP. Surgical management of cervical soft disc herniation: a comparison between the anterior and posterior approach. Spine 1990;15:1026 –30. 12. Wirth FP. High speed drills. In: Wilkins RH, Rengarchary SS (eds). Neurosurgery. New York: McGraw– Hill, 1996:591– 4. 13. Lavyne MH, Bilsky MH. Epidural steroids, postoperative morbidity, and recovery in patients undergoing microsurgical lumbar discectomy. J Neurosurg 1992; 77:90 –5. 14. Brain WR, Northfield D, Wilkinson M. The neurologic manifestations of cervical spondylosis. Brain 1952;75: 187–225. 15. Bertalanffy H, Eggert HR. Complications of anterior cervical discectomy without fusion in 450 consecutive patients. Acta Neurochir 1989;99:41–50. 16. Martins AN. Anterior cervical discectomy with and without interbody bone graft. J Neurosurg 1976;44: 290 –5. 17. Dowd GC, Wirth FP. Anterior Cervical Discectomy: is Fusion Necessary? J Neurosurg (Spine 1) 1999;90:8 – 12. 18. Connolly ES, Seymour RJ, Adams JE. Clinical evaluation of anterior cervical fusion for degenerative cervical disc disease. J Neurosurg 1965;23:431–7. 19. Ducker TB, Zeidman SM. The posterior approach for cervical radiculopathy. Neurosurg Clin N. A. 1993;4: 61–74. 20. Simeone FA. Posterior discectomy for soft cervical disc. In: Al–Mefty O, Origitano TC, Harkey HL (eds). Controversies in Neurosurgery. New York: Thieme, 1995:227– 8. 21. Rosenorn J, Hansen EB, Rosenorn MA. Anterior cervical discectomy with and without fusion. J Neurosurg 1983;59:252–5. 22. Savolainen S, Rinne J, Hernesniemi J. A prospective
COMMENTARY
This is a very well-written paper presenting for the first time a randomized study comparing three different surgical approaches. We all know that pain relief can be obtained in nearly all cases of radiculopathy due to lateral cervical disc herniation, no matter what surgical approach is used. But what is strange, at least as far as my experience and the data in the literature are concerned, is the assertion that the results after anterior diskectomy without fusion were as good as after an anterior approach with fusion. Moreover, I must ask myself how much reliability can be given to a series of 72 patients (22 FOR, 25 ACD, and 25 ACDF), considering that only 60% of them could be followed long-term. In some of these cases, the duration of symptoms before operation was only 1 week. How many of these patients might have obtained long-lasting relief from their symptoms without surgery? Would the authors be able to duplicate these results with a large number of patients who were refractory to conservative treatment? I can’t help saying that, in my opinion, in cases of lateral discal hernia impinging on the foramen to any degree, the posterior approach, as advocated by Scoville and Frykholm, is mandatory. I see no reason for performing an anterior approach (with graft!) in such cases. In my hands, at least (more than 400 anterior operations for medial and mediolateral discs or spondylosis, and 95 posterior operations for lateral discs), the anterior approach requires more time and sometimes leads to complications, such as dysphonia and graft displacement, which do not occur when the posterior approach is used. I have also seen, though rarely, cases in which a fragment of the disc was left in the foramen after an anterior diskectomy, which had to be removed via the posterior route in a second operation. Carlo A. Pagni Clinica Neurochirurgica Universita ` degli Study di Torino Turin, Italy This is a carefully done prospective, randomized study which compares outcome following either an anterior cervical diskectomy; anterior cervical diskectomy and interbody fusion; or cervical laminotomy, medial facetectomy, and foraminotomy. The
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study is important because rarely are the three procedures compared in this manner. It is of interest that the results indicate that the outcome of each of the three operations was similar. The study was not designed to answer the question of what factors related to the patient are appropriate to consider when advising a particular operation. In light of the findings, though, that would seem to be a worthwhile question to address in the future.
and currently employed with extravagance beyond reason. Assuming Wirth and colleagues will continue to use their foraminotomy approach for some patients, I would suggest that the plane of dissection not be undertaken “through the muscle” but with a slightly longer incision such as that which I have repeatedly advised [2,3], avoiding muscle damage, postoperative pain, and even allowing for ambulatory surgery as advocated by Tomaras et al. [4].
Franklin C. Wagner, Jr., M.D. Department of Neurosurgery University of Illinois at Chicago Chicago, Illinois
Charles A. Fager, M.D. Neurosurgeon Burlington, Massachusetts
Dr. Wirth et al. have confirmed the proposition that a well-designed study of a small number of patients can be meaningful in clarifying the conflicting surgical opinions that have existed since the introduction of anterior cervical diskectomy. My own bias has always been in favor of the posterolateral approach with foraminotomy, which has through long years of experience proved to be among the most gratifying operations in neurosurgery. I have now had the pleasant experience of seeing patients ranging up to 35 years after surgery who have not only had an excellent long-term result, but also no disturbance in the architecture of the cervical spine beyond that of the normal aging process. Nor have I seen recurrence after this approach as reported by the authors, though there have been a small number of patients in whom a retained fragment of disc required secondary surgery. The fact that the authors’ results have been just as good with anterior operations quite pointedly argues to the importance of the indications for surgery, rather than the approach that they wisely undertook specifically for single-level lateral disc herniation with radiculopathy. The prospective determination to select such candidates virtually rules out the failures so commonly seen with multiple-level diskectomy and fusion for neck pain alone, headache, post-traumatic soft tissue injury, and degenerative changes that are not clearly symptomatic. It is difficult to argue against such success of anterior diskectomy, yet it also seems clear from this study that fusion need not be done and its complications can be avoided. Of even greater significance is the fact that the authors achieved excellent results without the unnecessary placement of hardware advocated by Caspar [1] and others,
REFERENCES 1. Fager CA, Wirth FP, Yarzagaray L, Wissinger JP, Caspar W. Extruded cervical disc. Surg Neurol 1996;45:512– 6. 2. Fager CA. The atlas of spinal surgery. Philadelphia: Lea & Febiger, 1989. 3. Fager CA. Role of laminotomy in cervical disc herniation. Mt. Sinai Bull 1994;61:228 –32. 4. Tomaras CR, Blacklock JB, Parker WD, Harper RL. Outpatient surgical treatment of cervical radiculopathy. J Neurosurg 1997;87:41–3.
This paper by Wirth et al. demonstrates that good results can be obtained for a ruptured cervical disc using any one of three standard procedures— cervical laminectomy and foraminotomy (FOR), anterior cervical diskectomy (ACD) and ACD with fusion (ACDF). Simple FOR did well, but generally had more postoperative pain. ACD had a higher incidence of kyphosis and ACDF had a longer time to return to work. The paper does not specify the reason for the delay in returning to work. ACDF was carried out using iliac crest homograft, and the attendant hip pain may be the problem. The use of allografts would obviate this problem. More recently, many neurosurgeons are using titanium plates with the idea that it decreases pain, returns the patient to work sooner, and reduces the need for a collar. As far as I know, there is no published report of a study comparing ACDF using allograft without and with plating, so we do not know if plating is better. In the last 2 years, I have routinely carried out ACDF using a fibular allograft for cervical ruptured disc—no plate. Each patient gets a soft collar that may be discarded when the patient feels like it (usually one week or less). The patient can also return to work when comfortable, usually 2 to 4 weeks unless they do heavy labor. I doubt if having a plate would be better. Hopefully, some group will carry
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out a controlled study. It should result in a significant decrease in cost. Harold D. Portnoy, M.D. Neurosurgeon Pontiac, Michigan Dr. Wirth has reported a prospective series evaluating three common methods for the management of a unilateral monoradicular syndrome, secondary to a cervical disc herniation. Even though the follow-up period is short, Dr. Wirth has been able to follow his patients for 5 years, and has sufficient information available to support his conclusion. Of particular interest is the reported fusion rate of 82% after anterior cervical diskectomy and 80% after anterior cervical diskectomy with graft. This supports my personal impression that a graft is not necessary for a successful outcome. The interested reader should review the report by Drs. Dowd and Wirth [1], wherein a similar finding was reported with the treatment of cervical spondylosis with as-
sociated neurologic deficit. Fusion with a graft was found to be unnecessary for a successful outcome. The incidence of postoperative neurologic deficit does not vary significantly between the three treatment groups, and it is important to note that the deficit cleared within 2 months after the operative procedure. Perhaps the initial euphoria of having survived an operative procedure somewhat clouds the patient’s judgement regarding pain relief. Symptomatic relief was not as universally reported at the 2-month interval, but overall, the reported incidence of satisfactory symptomatic relief supports the premise that surgical management of a unilateral monoradicular syndrome secondary to a cervical disc herniation is the treatment of choice, and remains the gold standard against which nonsurgical therapies should be compared. Harry O. Cole, M.D. Neurosurgeon Chesterfield, Missouri