Spine Surgery at an Ambulatory Surgery Center

Kenneth A. Pettine, M.D. and Carter R. Mohnssen

Abstract

The purpose of this paper is to prospectively evaluate every spine surgery case performed at an ambulatory surgery center (ASC) from April 2005 through 2008 (1,030 cases). We wanted to ascertain whether spine surgery can be performed with safety and efficacy at an ASC.

The data was based on a prospective analysis of every spine surgery performed at the ASC; the 1,030 total cases consisted of 653 instrumented surgeries and 377 non-instrumented cases. For lumbar cases, each patient was evaluated pre-operatively and post-operatively up to three years with an oswestry disability index (ODI) and a visual analogue scale (VAS). The protocol was the same for cervical cases; however, each patient completed a neck disability index (NDI) instead of an ODI. Data such as OR time, PACU time, and convalescent care time was also obtained.

1-Level and 2-Level anterior cervical discectomy and fusions (ACDF) showed significant improvement in NDI and VAS at one year post-op. OR time averaged 83 minutes for both surgeries and the patients spent an average of 20.5 hours in convalescent care. Cervical artificial disc replacements (ADR) showed significant NDI and VAS improvement at six month follow-up, and posterior lumbar fusion (PLF) patients showed a significant improvement of ODI and VAS as well. Average OR time for PLF was 3 hours, and average convalescent care was 48 hours. Lumbar ADR showed significant ODI and VAS improvement at two year follow-up; anterior lumbar interbody fusion (ALIF) had significant ODI and VAS improvements as well. Sacroiliac joint fusion and noninstrumented surgical patients showed clinical improvements. Complications for all surgeries were minimal.

Based on our results, 1-Level and 2-Level ACDF, 1-Level ALIF, lumbar nerve decompressions, microdiscectomies, and lumbar and cervical ADRs can be performed safely and with efficacy at a typical ASC. Posterior lumbar and cervical fusions and SI joint fusions cannot be performed at a pure ASC because more than half of the patients in each group required longer than 24 hour convalescent care. At an ASC with a convalescent care center, however, these surgeries are possible.

Introduction

The purpose of this paper is to prospectively evaluate every spine surgery case performed at an ambulatory surgery center (ASC) from April 2005 through 2008 (1,030 cases). All cases were performed at the Loveland Surgery Center. Based on this analysis of results, conclusions can be made to ascertain whether spine surgery can be performed with safety and efficacy in an ASC setting. This may have important implications for providing quality surgical care with lower costs at an ASC versus a traditional hospital setting.

The Loveland ambulatory surgery center (LSC) consists of three operating rooms and a preoperative/post-operative recovery area. It is associated with a convalescent center that consists of four inpatient beds. Patients can be kept in the convalescent center indefinitely. The LSC is located in a single building with two separate licenses. The Loveland Surgery Center has an ambulatory surgery center license, and the convalescent center has a convalescent license similar to a nursing home license. The two facilities are connected by a door. A spine surgery patient typically undergoes recovery room resuscitation and is then transferred to the convalescent center or is discharged directly from the ASC. The convalescent center has a 1:1 or 1:2 nurse to patient ratio of care. Amenities include fresh flowers, candy and catered food served on real china with cloth napkins and silverware. Physical therapy is provided by outsourced physical therapists who come to the convalescent center. Pain control is typically achieved through intrathecal Duramorph in the lumbar fusion patients, patient-controlled anesthesia or IV and appropriate PO medications in all other patients. The Loveland ambulatory surgery center is joint commission accredited.

Materials and Methods

The following data is based on a prospective analysis of every spine surgery performed at the LSC from April 2005 through 2008. The data consists of 653 instrumented spine cases and 377 noninstrumented spine cases. This represents a total of 1,030 spine surgery cases. The instrumented spine cases are listed in Table 1. Each type of spine surgery will be individually discussed. Every patient included in this analysis was prospectively analyzed. They were pre-operatively evaluated with an oswestry disability index (ODI) for the lumbar patients and a neck disability index (NDI) for the cervical patients. In all patients a pre-operative visual analogue scale (VAS) was obtained. This same data collection was obtained post operatively at every follow-up visit up to three years post-operative. Data was collected every minute in the operating room and recovery room as well as every hour in the convalescent center. All perioperative complications were recorded along with any unplanned transfers.

Instrumented Spine Surgery

Surgery

Number of Patients

Anterior Cervical Discectomy and Fusion (ACDF): 1 Level

108

ACDF: 2 Level

82

ACDF: 3 Level

3

Posterior Cervical Fusion

7

Cervical Artificial Disc

57

Anterior Lumbar Interbody Fusion

9

Posterior Lumbar Fusion (PLF): 1 Level

166

PLF: 2 Level

102

PLF: 3 Level

30

Lumbar Artificial Disc

83

SI Joint Fusion

6

TOTAL:

653

 

Table 1

RESULTS

Anterior Cervical Discectomy and Fusion

The results of anterior cervical anterior cervical discectomy and fusion (ACDF) with plating were analyzed in 193 patients. Table 2 details the time in the OR, time in the PACU and time in the convalescent care unit for the 1-level and 2-level fusion patients (190 total). There were no perioperative complications and no unplanned transfers in these patients. Figures 1 and 2 detail the mean change in pre-operative and one year post-operative NDI and VAS scores for the one- and two-level anterior cervical fusions. Please note the statistically significant improvement in the clinical results of these patients. In terms of patient satisfaction rates following anterior cervical fusion, 95% of the patients were highly satisfied with their convalescent care room. Ninety-seven percent of patients were extremely satisfied with their nursing care and 95% of the patients were highly satisfied with their overall experience of undergoing a one- or two-level anterior cervical fusion at the ASC.

Conclusions for ACDF: Based on the statistically significant improvement in VAS and NDI with a lack of complications, this data indicates one- and two-level anterior cervical discectomy and fusions can be safely performed with efficacy at an ambulatory surgery center. All patients left the facility in less than 24 hours.

Results of Anterior Cervical Discectomy and Fusions (ACDF)

1-Level and 2-Level

OR Time

PACU Time

Convalescent Care

Patients

1-Level

81.7 min.

92.5 min.

20.7 hrs

108

2-Level

84.4 min.

80.8 min.

20.3 hrs

82

 

Table 2

 

Mean Change from Pre-Op to One Year Post-Op
1-Level ACDF

Pre-Op

1 Year

NDI

63.3

24.6 (p<0.01)

VAS (mm)

75.0

27.1 (p<0.02)

 

Figure 1

Mean Change from Pre-Op to One Year Post-Op
2-Level ACDF

Pre-Op

1 Year

NDI

64.0

42.0 (p<0.04)

VAS (mm)

78.8

40.7 (p<0.03)

 

Figure 2

Posterior Cervical Fusion

Posterior cervical fusions were performed in seven patients. There were no perioperative complications except for a superficial wound infection in one patient. Four of these patients required more than 24-hour recovery. There were no unplanned transfers.

Conclusions for Posterior Cervical Fusions: Despite being nearly free of perioperative complications, posterior cervical fusions are not typically able to be performed in a pure ASC because half of the cases required more than 24 hours of recovery prior to discharge home.

Cervical Artificial Disc Replacements

One- and two-level cervical artificial disc replacements were performed in 57 patients. The OR time averaged 84 minutes with average time in the PACU at 81 minutes and average time in the convalescent center of 20 hours. Pre-operative NDI decreased from 54.6 to 31.8 at six-month follow-up with a p-value < 0.03, and pre-operative VAS decreased from 74 to 39 at six-month follow-up with a p-value < 0.02. There were no infections, nerve injuries, reoperations or implant transfers in any of these 57 patients following cervical artificial disc replacement.

Conclusions for Cervical Artificial Disc Replacements: Based on statistically significant improvement in NDI and VAS without surgical complications, this data indicates cervical artificial disc surgery at one and two levels can be safely performed at an ambulatory surgery center. All patients left the facility within 24 hours of their surgery.

Posterior Lumbar Fusion

Posterior lumbar fusion data was collected in 298 patients. Table 3 lists the time in the OR, time in the PACU and time in the convalescent center in one-, two- and three-level procedures. The clinical results of one- and two-level fusion at one-year follow-up is listed in Figures 3 and 4. After posterior lumbar fusion, 93% were satisfied with their pain control, 99% were highly satisfied with their nursing care and 97% of the patients expressed a high satisfaction rate with their overall ASC experience. Complications occurred in 13 of the 298 patients for an incidence of 4.3% (see Table 4).

Three patients, representing 1% of the overall group, were returned to the OR prior to their discharge. One patient was returned to drain a hematoma, one patient to undergo a redo dural tear repair and one patient to undergo a redo nerve decompression. Five patients had an unplanned transfer to the hospital, representing 1.7% of the patients. The indications for these transfers were for enhanced pulmonary care in four patients and an atrial thrombosis in one patient. Unplanned transfers to the rehab unit occurred in two patients for an incidence of 0.7%. There were perioperative complications in three patients, which consisted of a DVT in two patients and a nerve injury in one patient.

Conclusions for Posterior Lumbar Fusions: Based on statistically significant improvement of VAS and ODI with minimal complication rates, the data would indicate that lumbar fusion at one, two and even three levels can be safely performed with efficacy at an ambulatory surgery center if the patient is allowed to undergo inpatient post-operative care at a convalescent center for 48 hours.

Results of Posterior Lumbar Fusions (PLF)
1-Level, 2-Level, and 3-Level

OR Time

PACU Time

Convalescent Care

Patients

1-Level

157.5 min.
(2.5 hrs)

77.6 min.

42.1 hrs

166

2-Level

186.1 min.
(3 hrs)

85.8 min.

50.1 hrs

102

3-Level

213 min.
(3.5 hrs)

91.1 min.

55.1 hrs

30

 

Table 3

Clinical Results of 1-Level Lumbar Fusion at 1 Year Follow-Up

Pre-Op

1 Year

NDI

56.7

40.3 (p<0.05)

VAS (mm)

81.0

45.9 (p<0.03)

 

Clinical Results of 2-Level Lumbar Fusion at 1 Year Follow-Up

Pre-Op 1 Year
NDI 57.0 46.2 (p<0.05)
VAS (mm) 81.0 45.4 (p<0.03)

 

Posterior Lumbar Fusions (PLF): Complications

Complication

Number of Patients (Overall Rate of Incidence)

Return to O.R.

3 (1.0%)

To Drain Hematoma

1

For Dural Tear Repair

1

For redo Nerve Decompression

1

Unplanned Transfer to Hospital

5 (1.7%)

For Pulmonary Care

4

For Arterial Thrombosis

1

Unplanned Transfer to Rehab. Unit

2 (0.7%)

Operative Complications

3 (1.0%)

D.V.T.

2

Nerve Injury

1

TOTAL:

13 (4.3%)

 

Table 4

Lumbar Artificial Disc Replacements

Lumbar artificial discs replacements were analyzed in 83 patients. These were all one-level cases at L4-5 or L5-S1. Time in the OR averaged 100 minutes, time in the PACU averaged 83 minutes and time in the convalescent center averaged 21 hours. There was one intra-operative complication with a 2mm vein laceration requiring intra-operative repair, and one patient had an arterial thrombosis requiring transfer to the hospital for immediate thrombectomy. Two patients were also returned to the OR within 24 hours to reposition the implant in one patient and convert the patient to an anterior lumbar interbody fusion in the other patient. Clinical outcomes at two-year follow-up are listed in Chart 9. Please note all of this data was generated as part of an FDA IDE study and has been audited by the FDA.

Conclusions for Lumbar Artificial Disc Replacements: These results indicate lumbar artificial discs can be performed with safety and efficacy at an outpatient ambulatory surgery center. All patients were discharged within 24 hours of surgery.

 

Clinical Results of 1-Level Lumbar Artificial Disc Replacements at 2 Year Follow-Up

Pre-Op Post-Op
ODI 60.8 18.3 (p<0.001)
VAS (mm) 81.0 27.0 (p<0.001)

 

Figure 5

 

Anterior Lumbar Interbody Fusion

Nine patients underwent an anterior lumbar interbody fusion (ALIF). All of these cases were performed at L5-S1. The results were similar to the artificial disc patients and all patients left the facility within 24 hours.

Conclusions for ALIF: The results for these surgeries indicate that ALIF procedures can be performed with safety and efficacy at an outpatient ASC.

Sacroiliac Joint Fusion

Sacroiliac (SI) joint fusions were performed in six patients. There were no perioperative complications or unplanned transfers in these patients. However, on the average, they did require greater than 24-hour recovery and would not be considered as a pure ASC patient.

Non-instrumented Spine Surgery

Non-instrumented spine surgery, microdiscectomies and/or nerve decompressions were performed in 377 patients. OR time averaged 74 minutes, PACU time averaged 78 minutes and time in the convalescent center averaged 19 hours. One patient was returned to the OR to drain fluid within 24 hours of the initial surgery. None of these patients required unplanned transfers to the hospital or rehab unit.

Conclusions for non-instrumented spine surgery: Based on clinical improvement and lack of complications, follow-up data would indicate that lumbar microdiscectomies and nerve decompressions can be safely and efficaciously performed at an ambulatory surgery center.

Cost Benefits

Outside insurance cost analysis indicates instrumented spine surgery can be performed at a 60% cost savings over the hospital.1 Most of this savings is in reduced hospital time and implant cost.

Comparison of similar spine surgeries performed at the hospital indicates there is 20% less operating room time at the ASC.2 The average patient is discharged within two days of a lumbar fusion from the Loveland Surgery Center versus 3-5 days for a similar patient at the hospital.2

Infections

Infections were defined as either superficial, which are those treated with oral antibiotics as the patient’s only treatment combined with dressing changes, versus a deep infection, which is defined as requiring a reoperation for debridement along with either IV or PO antibiotics. These definitions are based on Horan, et al.23 In all of the discectomy or nerve decompression patients, there were seven superficial infections and one deep infection. There was one superficial infection in a posterior cervical fusion patient and there was one superficial infection in a cervical artificial disc patient. There were two superficial infections in the posterior lumbar fusion group and three deep wound infections treated with debridement and insertion of a wound vac. One of these three deep infections had a MRSA infection. All of these patients required 6-8 weeks of IV antibiotics. Deep wound infections thus occurred in 0.003% of the patients having a microdiscectomy and/or nerve decompression. Deep wound infections occurred in 1% of the patients having a posterior lumbar fusion.

Discussion

There is an increasing interest in the United States to provide quality healthcare at a lower cost. The importance of this paper is to show with prospective collected data of every spine surgery performed at an ambulatory surgery center (ASC) whether this can be accomplished. It is important to emphasize every surgery performed at the ASC was included in this analysis. This data indicates anterior cervical decompression and fusion one- and two-levels, cervical artificial disc replacements, lumbar artificial disc replacements, lumbar nerve decompressions and microdiscectomies can be performed at an ambulatory surgery center. Cost savings compared to the hospital setting average 60% less at the ASC versus the hospital.1 Patient satisfaction for overall care is above 95%. The average time in the operating room is 20% less than a similar case performed at the hospital. All of these facts emphasize the advantages of performing spine surgery at an ASC versus a hospital setting. Other authors have reported on specific surgical procedures that can be performed at an ambulatory surgery center. These include Tsou, et al. describing a transforaminal endoscopic discectomy performed in an outpatient setting.3 Pimenta, et al. published a report of 100 consecutive cases of the PCM cervical artificial disc performed in an outpatient setting.4 Rampersaud, et al. published on 67 patients undergoing a lumbar laminoplasty for stenosis as an outpatient procedure.5 Moreland, et al. published on a prospective study of 212 patients undergoing outpatient microdiscectomy with safety and efficacy.6 Mirzai, et al. published a series of 52 consecutive patients undergoing nucleoplasty for a lumbar herniated disc successfully under local anesthesia as an outpatient.7 Tsou also published a series of 219 patients undergoing endoscopic decompression for sequestered disc herniations, all performed as an outpatient procedure.8 Villavicencio, et al. published on the safety of outpatient anterior cervical discectomy and fusion with instrumentation successfully performed in 103 patients.9 Treatment of a herniated lumbar disc with various methods of discectomy being successfully performed in an outpatient procedure has been reported by Zahrawi, Bookwalter, et al., An, et al., Obenchain, Bednar, et al., and Kahanovitz, et al.10-15 Anterior cervical fusion with plating has been reported to be a safe and efficacious procedure performed in an outpatient setting by Villavicencio, et al., Stieber, et al. and Przybylski, et al.9, 16, 17 A hardcover text titled Outpatient Spinal Surgery edited by Perez-Cruet, M.D., and Fessler, M.D., was published in 2002 describing outpatient minimally invasive spine surgery.18

Edmonston, et al., recently published an overall infection rate of 0.33% in over 11,000 consecutive orthopedic procedures performed over five years at an ASC.19 This low infection rate compares variably with other studies and argues toward increased use of an ASC in order to minimize the risk of nosocomial infection.20-22

This study indicates lumbar fusion performed with a traditional midline open fashion normally requires a 2-3 day inpatient stay. Lumbar fusion can be performed at the Loveland Surgery Center because of the convalescent center. There is continual development of minimally invasive surgical (MIS) techniques in spine surgery. Examples are the X-LIF approach developed by Nuvasive. These newer MIS techniques may result in even lumbar fusion surgery being performed with less than a 24-hour stay. This would allow lumbar fusion surgery to be performed at an ASC.

Conclusions

This data indicates the surgeries listed in Table 5 can be performed with safety and statistically significant clinical efficacy at an ambulatory surgery center. Posterior lumbar fusion surgery performed with the standard midline technique with pedicle screws normally requires more than 24 hours of recovery prior to discharge home. However, more minimally invasive techniques such as the X-LIF procedure may allow one-level and even multi-level lumbar fusions to be performed at an ambulatory surgery center in the future.

Spine Surgeries that can be Safely Performed at an Ambulatory Surgery Center (ASC)

  • Anterior Cervical Fusions (One, Two, and possibly Three levels)
  • Anterior Lumbar Interbody Fusions (One Level)
  • Lumbar Nerve Decompressions
  • Microdiscectomies
  • Lumbar and Cervical Artificial Disc Replacements
  • Lumbar Fusions performed with XLIF or other minimally invasive techniques

Table 5

References

1 Anthem Blue Cross Blue Shield of Colorado, June 2004.

2 Internal practice audit results of operating room times and inpatient hospital days comparing similar patients with the same surgeons at an ASC versus local hospital.

19 Edmonston DL, Foulkes GD: Infection rate and risk factor analysis in an orthopedic ambulatory surgical center. J Surgical Orthopaedic Advances 2010.

20 Maksimović J, Marković-Denić L, Bumbasirević M, et al. Surgical site infections in orthopedic patients: prospective cohort study. Croat Med J 49(1):58-65, 2008.

21 Gastmeier P, Sohr D, Brandt C, et al. Reduction of orthopaedic wound infections in 21 hospitals. Arch Orthop Trauma Surg 125:526-30, 2005.

22 Whitehouse JD, Friedman ND, Kirkland KB, et al. The impact of surgical-site infections following orthopedic surgery at a community hospital and a university hospital: adverse quality of life, excess length of stay and extra cost. Infect Control Hosp Epidemiol 23:183-9, 2002.

23 Horan, TC, Mangram, AJ, Pearson ML, et al. Guideline for prevention of surgical site infection, 1999. Infection Control and Hospital Epidemiology 20(4):247-78, 1999.

 

Annotated Bibliography

3 Tsou PM, Yeung CA, Yeung AT: Posterolateral transforaminal selective endoscopic discectomyand thermal annuloplasty for chronic lumbar discogenic pain: a minimal access visualized intradiscal surgical procedure. The Spine Journal 2004;4:564-73.

Endoscopic discectomy and thermal annuloplasty for chronic lumbar discogenic pain has been reported by Tsou, et al, to be an outpatient procedure. The authors report minimum two-year follow-up on a selected group of 113 patients with chronic lumbar discogenic pain who underwent the described procedure. Between 1997 and 1999, this group performed lumbar endoscopic surgery on 510 patients for various pathologies. All of the procedures were performed in an outpatient setting.

4 Pimenta L, et al: Porous Coated Motion (PCM) cervical disc replacement – report of 100 consecutive cases as part of an FDA pilot study performed in an outpatient setting. Spine Arthrop Society. Vienna-Austria; May, 2004.

5 Rampersaud R, AlBelooshi A, Lewis S: Outpatient Spinal Stenosis Decompression Using a Minimally Invasive Modified Lumbar Laminoplasty Technique: Feasibility and Early Outcomes. J Bone Joint Surg British Volume 90-B, Supp_I, 150; 2008.

Rampersaud, et al, have reported on lumbar decompressions in 67 patients with minimum six-month follow-up for lumbar stenosis performed in an outpatient setting. They state ambulatory surgery management for neurogenic claudication has the potential to significantly improve cost and resource utilization.

6 Moreland D, Lewis PJ, Egnatchik J: Outpatient Lumbar Microdiscectomy: Age relationship to outcome and tempered expectations. Spine Journal 2, Issue 5 Supp:124, 2002

Moreland, et al, reported on a prospective study of 212 patients undergoing outpatient lumbar microdiscectomy in a private community neurosurgical practice. Their data supports the evidence that outpatient lumbar microdiscectomy is a very safe and effective means of addressing sciatic pain resulting from disc herniation.

7 Mirzai H, Tekin I, Yaman O, Bursali A: The results of nucleoplasty in patients with lumbar herniated disc: a prospective clinical study of 52 consecutive patients. The Spine Journal 2007;7:88-93.

They published on 52 consecutive patients undergoing percutaneous nucleoplasty under local anesthesia as an outpatient.

8 Tsou PM, Yeung AT: Transforaminal endoscopic decompression for radiculopathy secondary tointracanal non-contained lumbar disc herniations: outcome and technique. The Spine Journal2002;2:41-8.

They published on a consecutive series of 219 patients undergoing an endoscopic decompression for sequestered disc herniations, all performed as an outpatient procedure. Each patient was discharged within five hours of the procedure.

9 Villavicencio AT, Pushchak E, Buneikiene S, Thramann J: The safety of instrumented outpatient anterior cervical discectomy and fusion. The Spine Journal 2007;7:148-53.

They published on the safety of instrumented outpatient anterior cervical discectomy and fusion. They studied a total of 103 patients undergoing an anterior cervical decompression and fusion (ACDF). Ninety-nine of the patients undergoing a single or two-level ACDF were discharged less than 15 hours after their surgery with a median time of eights and a range of 2-15 hours in four patients. Three-level ACDF patients were discharged after a 23-hour stay. They felt performing ACDF with instrumentation on an outpatient basis is feasible and not associated with higher overall or hardware-related complication rates as compared with similar surgeries performed in a hospital inpatient setting.

10 Zahrawi F: Microlumbar discectomy. Is it safe as an outpatient procedure: Spine 1994;19:1070-4.

11 Bookwalter JW 3rd, Busch MD, Nicely D: Ambulatory surgery is safe and effective in radiculardisc disease. Spine 1994;19:526-30.

12 An HS, Simpson JM, Stein R: Outpatient laminotomy and discectomy. J Spinal Disord 1999;12:192-6.

Previous studies by Zahrawi, et al; Bookwalter, et al; and An, et al, regarding lumbar microdiscectomy, laminotomy and root decompression procedures have demonstrated the overall cost of surgery can be reduced by performing the procedure on an outpatient basis. Similar results have been reported regarding non-instrumented ACDF by Silvers, et al. Silvers, et al, reported a 45% savings rate between inpatient and outpatient groups.

13 Obenchain TG: Speculum lumbar extraforaminal microdiscectomy. The Spine Journal 2001;1:415-21.

Obenchain published on 50 consecutive patients undergoing a speculum lumbar extraforaminal microdiscectomy performed successfully on an outpatient basis.

14 Bednar DA: Analysis of factors affecting successful discharge in patients undergoing lumbar discectomy for sciatica performed on a day-surgical basis. J Spine Disord 1999;12:192-6.

15 Kahanovitz N, Viola K, McCulloch J: Limited surgical discectomy and microdiscectomy. Spine 1989;14:79-81.

Bednar and Kahanovitz, et al, have also reported successful outpatient lumbar microdiscectomy techniques.

16 Stieber, JR, Brown K, Donald GD, Cohen JD: Anterior cervical decompression and fusion with plate fixation as an outpatient procedure. Spine Journal 2005;5:503-7.

They published on successfully performing ACDF with plate fixation as an outpatient procedure.

17 Przybylski, G, Mitchell W: Safety of Outpatient Cervical Spine Surgery. Spine Journal 2006;6, Issue 5 Supp:115S-6S.

They have reported on 100 consecutive patients prospectively undergoing anterior cervical fusions at an outpatient community hospital. They concluded outpatient cervical surgery can be performed safely.

18 Outpatient Spinal Surgery edited by Mick Perez-Cruet, M.D. and Richard Fessler, M.D. was published in 2002. It is a textbook that lies at the crossroads of medicine and business. This textbook is a comprehensive reference to operative techniques of cervical and lumbar surgery that can be performed in an outpatient surgery center.