Use of the operating microscope in anterior cervical discectomy without fusion HAL L. HANKINSON,M.D., AND CHARLES B. WILSON, M.D. Department of Neurological Surgery, University of California School of Medicine, San Francisco, California The authors report their experience using the operating microscope in 52 anterior cervical discectomies without fusion. They found long-term results highly satisfactory, even in difficult cases with multiple-level disease, and complications from bone grafting were obviated. They highly recommend this approach for radicular, nonradicular, or myelopathic symptoms. KEY WORDS 9 cervical d i s c e c t o m y intervertebral disc
INCE the advent of the anterior approach to cervical disc disease, several techniques for this procedure have been described by both orthopedic and neurological surgeons. In the last 5 years, we have adopted with some modifications the method advocated by Hirsch, et al., 5 Boldrey, ~ Susen," and, most recently, Murphey and Gado. 8 Extending anterior cervical discectomy without interbody fusion to include extensive osteophyte removal, we have performed 52 operations on 51 patients. The results of these procedures are the subject of this report.
s
Clinical M a t e r i a l and M e t h o d s
S u m m a r y o f Patients Fifty-two operations were performed on 51 patients with cervical disc disease during the period April, 1969, to March, 1974. All operations were carried out by or under the 452
9 fusion
9
direct supervision of one surgeon (CBW). The patients ranged in age from 31 to 76 years; 31 were males and 20 females. The diagnosis in 13 was acute cervical disc herniation, and in 38 degenerative cervical disc disease or cervical spondylosis. Symptoms varied in duration from 1 month to 16 years. Radicular symptoms, characterized by pain or neurological deficit, were seen in 40 patients, Nonradicular pain was present in 45, and myelopathy was evident in 12. Preoperatively, all patients had plain x-ray films of the cervical spine, with or without flexion and extension views. Findings in 50 were considered abnormal; of the 49 who had myelograms, 43 showed abnormalities. The only discogram done was positive; eight of nine patients had a positive electromyogram. All patients had previously received conservative therapy. Nine had had a prior operation; six of these patients had had cervical laminectomies. Twenty-five had a history of trauma. J. Neurosurg. / Volume 43 / October, 1975
Anterior cervical discectomy without fusion TABLE 1 Operated levels in 51 patients
Levels Operated single
C3-4 C4-5 C5-6 C6-7
two
No. of Cases 2 3 14 6
C3-4, C4-5 C4-5, C5-6 C5-6, C6-7
1 6 9
C3-4, C4-5, C5-6 C4-5, C5-6, C6-7
1 6
C3-4, C4-5, C5-6, C6-7 total
3
three four
25
16
7 3
51
portion of disc and anterior osteophyte, if present, is removed with a rongeur. The opening into the interspace need be no wider than 10 mm, with columns of disc preserved on both sides. The most difficult interspace is ordinarily done first, should the operation involve multiple levels. The operating microscope is then brought into the field and, using the air turbine drill with an angled adaptor and suction irrigation, the surgeon drills away a portion of the superior and inferior vertebral bodies to provide 5 to 6 mm of vertical exposure. This is done in such a fashion that the drilling is carried more laterally as the posterior aspect of the body is approached (Fig. 1); thus, the entire disc is not removed. Drilling is augmented by curettage as necessary to remove disc material and widen exposure. When posterior cortical bone is reached, drilling is terminated and dissection proceeds with the angled-up curettes. These instruments and the excellent light of the microscope allow extensive removal of posterior and lateral osteophytes under direct vision. When the cord and roots are free from impingement, hemostasis is obtained, and the wound is closed without a drain. Often, although not always, the posterior longitudinal ligament is opened and the dura is inspected directly. Results
F~G. I. Sketch illustrating bone removal and technique of root decompression. We operated on 90 levels; their distribution among patients is shown in Table 1. Postoperatively most patients required no external support, and only a very few needed more support than a soft collar. Technique
The anterior cervical spine is approached in the standard fashion, usually from the right side. Appropriate levels are localized by x-ray study and exposure maintained with two Cloward self-retaining retractors. An incision is made in the disc with a No. 15 blade and a J. Neurosurg. / Volume 43 / October, 1975
We were extremely gratified with the smooth postoperative course exhibited by all but a few patients. The postoperative stay varied from 3 to 38 days, with one exception. The average hospital period was about 8 days following operation; however, in many it was 4 to 6 days. One man was hospitalized for 107 days; this patient had a Chiari Type I malformation and hydrocephalus, and developed shunt obstruction and meningitis during his hospitalization. Operative complications are listed in Table 2. One patient who underwent a four-level operation had to have further osteophyte removal at C6-7 before the pain was resolved. Patients with Horner's syndrome, recurrent laryngeal palsy, and new radicular pain improved gradually. In one case, brachial plexitis was diagnosed after standard diagnostic studies failed to reveal a cause for postoperative pain and weakness. At this writing (1 month postoperatively), the condi453
H . L. L. Hankinson Hankinson a n d C. C. B. B. Wilson Wilson H. and TABLE 2
tion is clearing. The other complications, ininterscapular pain, were transient. cluding interscapular Complications occurring occurring in 52 operations operations Complications With two exceptions, all patients have been ffor o r cervical cervical disc disease followed by office examination or questionComplication No. of Cases Cases Complication naire, and in many cases, both. The follow-up period varied from 4 months to 5 years. neck and interscapular pain 5 Results from our last six patients are not indysphagia 3 pulmonary congestion congestion 2 2 eluded in this study because the follow-up cluded new radicular pain 2 period is currently too brief. Homer's syndrome syndrome transient Horner's 2 A questionnaire was sent to the first 39 laryngeal palsy* recurrent laryngeal palsy· 1 patients in the series; this method was chosen wound hematoma 11 to remove the influence of the surgeon in the brachial plexitis l plexitis 1 response. Thirty of these 39 responded, and discitis I discitis 1 exacerbation of pain requiring requiring the results are presented in Table 3. Twenty1 reoperation eight patients said that they were helped by discectomy the operation. Fifteen of the 30 have returned previous anterior discectomy •* This patient had had previous to the same level of work as prior to the onset and fusion fusion (Cloward). (Cloward). Table 4 summarizes the surof disability. Table geon's clinical impressions during follow-up visits. According to the grading system of e t a/.,7 a l . f l 31 of 35 patients followed in Odom, et TABLE 3 TABLE this way were considered to have excellent or Results o f questionnaire returned returned by by 30 patients patients Results ofquestionnaire good surgical outcomes. Nine of 12 patients with myelopathy myr were Classification Patient Classification followed by office examination. One had an Response Response to Acute Disc Disc Cervical Cervical excellent result, five good, two satisfactory, Acute Questionnaire Spondylosis Herniation Spondylosis and one poor. (10) (20) (10) (20) Murphey and Gado d~ reported radiographic presence of presence o f overall overall benefit benefit evidence of fusion in 72% of 18 cases in which yes 19 yes 9 19 discectomy had been performed at a single 1 1 no 1 1 level. They stated that neither incomplete fuestimated percentage of estimated percentage of sion nor failure of osteophyte resolution overall overall benefit benefit 1 100 70 1 I 100% precluded a good clinical result. This has also 90 7o-100 % 4 8 90%-100% been our observation in those patients who 75 %-90 ~o 2 75%-90% 2 have had postoperative postoperative radiographs. 50%-75 Vo 50%-75% 8 o0 performed a repeat myelogWe recently 1
INCE the advent of the anterior approach to cervical disc disease, several techniques for this procedure have been described by both orthopedic and neurological surgeons. In the last 5 years, we have adopted with some modifications the method advocated by Hirsch, et al., 5 Boldrey, ~ Susen," and, most recently, Murphey and Gado. 8 Extending anterior cervical discectomy without interbody fusion to include extensive osteophyte removal, we have performed 52 operations on 51 patients. The results of these procedures are the subject of this report.
s
Clinical M a t e r i a l and M e t h o d s
S u m m a r y o f Patients Fifty-two operations were performed on 51 patients with cervical disc disease during the period April, 1969, to March, 1974. All operations were carried out by or under the 452
9 fusion
9
direct supervision of one surgeon (CBW). The patients ranged in age from 31 to 76 years; 31 were males and 20 females. The diagnosis in 13 was acute cervical disc herniation, and in 38 degenerative cervical disc disease or cervical spondylosis. Symptoms varied in duration from 1 month to 16 years. Radicular symptoms, characterized by pain or neurological deficit, were seen in 40 patients, Nonradicular pain was present in 45, and myelopathy was evident in 12. Preoperatively, all patients had plain x-ray films of the cervical spine, with or without flexion and extension views. Findings in 50 were considered abnormal; of the 49 who had myelograms, 43 showed abnormalities. The only discogram done was positive; eight of nine patients had a positive electromyogram. All patients had previously received conservative therapy. Nine had had a prior operation; six of these patients had had cervical laminectomies. Twenty-five had a history of trauma. J. Neurosurg. / Volume 43 / October, 1975
Anterior cervical discectomy without fusion TABLE 1 Operated levels in 51 patients
Levels Operated single
C3-4 C4-5 C5-6 C6-7
two
No. of Cases 2 3 14 6
C3-4, C4-5 C4-5, C5-6 C5-6, C6-7
1 6 9
C3-4, C4-5, C5-6 C4-5, C5-6, C6-7
1 6
C3-4, C4-5, C5-6, C6-7 total
3
three four
25
16
7 3
51
portion of disc and anterior osteophyte, if present, is removed with a rongeur. The opening into the interspace need be no wider than 10 mm, with columns of disc preserved on both sides. The most difficult interspace is ordinarily done first, should the operation involve multiple levels. The operating microscope is then brought into the field and, using the air turbine drill with an angled adaptor and suction irrigation, the surgeon drills away a portion of the superior and inferior vertebral bodies to provide 5 to 6 mm of vertical exposure. This is done in such a fashion that the drilling is carried more laterally as the posterior aspect of the body is approached (Fig. 1); thus, the entire disc is not removed. Drilling is augmented by curettage as necessary to remove disc material and widen exposure. When posterior cortical bone is reached, drilling is terminated and dissection proceeds with the angled-up curettes. These instruments and the excellent light of the microscope allow extensive removal of posterior and lateral osteophytes under direct vision. When the cord and roots are free from impingement, hemostasis is obtained, and the wound is closed without a drain. Often, although not always, the posterior longitudinal ligament is opened and the dura is inspected directly. Results
F~G. I. Sketch illustrating bone removal and technique of root decompression. We operated on 90 levels; their distribution among patients is shown in Table 1. Postoperatively most patients required no external support, and only a very few needed more support than a soft collar. Technique
The anterior cervical spine is approached in the standard fashion, usually from the right side. Appropriate levels are localized by x-ray study and exposure maintained with two Cloward self-retaining retractors. An incision is made in the disc with a No. 15 blade and a J. Neurosurg. / Volume 43 / October, 1975
We were extremely gratified with the smooth postoperative course exhibited by all but a few patients. The postoperative stay varied from 3 to 38 days, with one exception. The average hospital period was about 8 days following operation; however, in many it was 4 to 6 days. One man was hospitalized for 107 days; this patient had a Chiari Type I malformation and hydrocephalus, and developed shunt obstruction and meningitis during his hospitalization. Operative complications are listed in Table 2. One patient who underwent a four-level operation had to have further osteophyte removal at C6-7 before the pain was resolved. Patients with Horner's syndrome, recurrent laryngeal palsy, and new radicular pain improved gradually. In one case, brachial plexitis was diagnosed after standard diagnostic studies failed to reveal a cause for postoperative pain and weakness. At this writing (1 month postoperatively), the condi453
H . L. L. Hankinson Hankinson a n d C. C. B. B. Wilson Wilson H. and TABLE 2
tion is clearing. The other complications, ininterscapular pain, were transient. cluding interscapular Complications occurring occurring in 52 operations operations Complications With two exceptions, all patients have been ffor o r cervical cervical disc disease followed by office examination or questionComplication No. of Cases Cases Complication naire, and in many cases, both. The follow-up period varied from 4 months to 5 years. neck and interscapular pain 5 Results from our last six patients are not indysphagia 3 pulmonary congestion congestion 2 2 eluded in this study because the follow-up cluded new radicular pain 2 period is currently too brief. Homer's syndrome syndrome transient Horner's 2 A questionnaire was sent to the first 39 laryngeal palsy* recurrent laryngeal palsy· 1 patients in the series; this method was chosen wound hematoma 11 to remove the influence of the surgeon in the brachial plexitis l plexitis 1 response. Thirty of these 39 responded, and discitis I discitis 1 exacerbation of pain requiring requiring the results are presented in Table 3. Twenty1 reoperation eight patients said that they were helped by discectomy the operation. Fifteen of the 30 have returned previous anterior discectomy •* This patient had had previous to the same level of work as prior to the onset and fusion fusion (Cloward). (Cloward). Table 4 summarizes the surof disability. Table geon's clinical impressions during follow-up visits. According to the grading system of e t a/.,7 a l . f l 31 of 35 patients followed in Odom, et TABLE 3 TABLE this way were considered to have excellent or Results o f questionnaire returned returned by by 30 patients patients Results ofquestionnaire good surgical outcomes. Nine of 12 patients with myelopathy myr were Classification Patient Classification followed by office examination. One had an Response Response to Acute Disc Disc Cervical Cervical excellent result, five good, two satisfactory, Acute Questionnaire Spondylosis Herniation Spondylosis and one poor. (10) (20) (10) (20) Murphey and Gado d~ reported radiographic presence of presence o f overall overall benefit benefit evidence of fusion in 72% of 18 cases in which yes 19 yes 9 19 discectomy had been performed at a single 1 1 no 1 1 level. They stated that neither incomplete fuestimated percentage of estimated percentage of sion nor failure of osteophyte resolution overall overall benefit benefit 1 100 70 1 I 100% precluded a good clinical result. This has also 90 7o-100 % 4 8 90%-100% been our observation in those patients who 75 %-90 ~o 2 75%-90% 2 have had postoperative postoperative radiographs. 50%-75 Vo 50%-75% 8 o0 performed a repeat myelogWe recently 1
