Abstract

Background: Can anterior cervical diskectomy/fusion (ACDF) be safely performed in ambulatory surgical centers (ASC’s: i.e. discharges 4-7.5 hr. postoperatively) that meet the following stringent “exclusion criteria”; elevated Body Mass Index (BMI), major comorbidities, age > 65, American Society of Anesthesiology (ASA) scores > II, and largely multilevel ACDF.

Materials: Presently, most ACDF are still being performed in hospital-based outpatient surgical centers (HBSC: utilizing 23-hour stays), or as inpatients.

Results: Notably, unreliable disparate study designs involving very different patient populations resulted in nearly comparable, but implausible outcomes for 1-level vs. multilevel ACDF series performed in ASC. A summary of these outcome data included the following rates of; i.e. postoperative hospital transfers (0-6%), 30-day (up to 2.2%), and up to 90 day (2.2%) emergency department (ED) visits, readmissions, and reoperations.

Conclusion: Nevertheless, it is just common sense that “less should be less”, that 1-level ACDF should involve less risk compared with multilevel ACDF procedures performed in ASC.

Keywords: Adverse events, Ambulatory surgi-center (ASC), Anterior cervical diskectomy/fusion (ACDF), Efficacy, Hospital-based outpatient surgi-center (HBSC), Inpatient facility, Morbidity, Outcomes, Safety, Single vs multilevel

INTRODUCTION

Can anterior cervical diskectomy/fusions (ACDF) be safely performed in ambulatory surgical centers (ASC- discharges 4-7.5 hrs. postoperatively) adhering to “stringent exclusion criteria”. As outlined in many studies, these exclusion criteria included; avoiding elevated BMI (i.e. obesity/ morbid obesity, non-routine “morphology”), major comorbidities, age > 65, American Society of Anesthesiology (ASA) scores > II, and as raised by Gennari et al., multilevel ACDF?[ 1 , 4 - 6 ] Presently, the majority of ACDF are still performed in hospital-based outpatient surgical centers (HBSC: utilizing 23-hour stays), or as inpatients.[ 1 , 4 - 6 , 8 , 9 ] Here, we analyzed outcomes of 1-level vs. multilevel ACDF performed in ASC, focusing on immediate postoperative hospital transfer rates, and up to 30 and 90 day postoperative emergency department (ED) visits, readmissions, and reoperations.[ 1 , 2 , 4 - 10 ] Again, our main question was whether ACDF could be safely performed in ASC. Furthermore, isn’t it common sense that “less (surgery) should be less (morbidity)””, that 1-level ACDF should involve “less risk” vs. multilevel procedures performed in ASC.[ 6 ]

“Careful Patient Selection” for ACDF Surgery in ASC Using Multiple “Exclusion Criteria”

Two Studies Emphasized Inclusion/Exclusion Criteria for 1-level ACDF to Be Performed in ASC

Two studies emphasized careful patient selection utilizing multiple “inclusion” and “exclusion criteria” for performing 1-level ACDF in ASC [ Tables 1 , 2 ].[ 5 , 8 ] In France, Gennari et al. (2018) noted that 90% of cervical 1-level ACDF were being successfully performed in ASC [ Table 1 ].[ 5 ] Notably, these patients were carefully selected utilizing “multiple inclusion criteria”; age < 65, only 1-level ACDF, ASA scores of < II, and patients were required to exhibit “standard morphology” (i.e. not including obesity/morbid obesity). Further, “exclusion criteria” included; age > 65, 3 + level ACDF, and ASA > II. Rossi et al. (2019) uniquely included 119 Medicare patients (i.e. all over 65 years of age) in ASA Grades I-III undergoing predominantly 1-level ACDF (103 patients).[ 8 ] They observed no immediate postoperative hospital transfers, a 2.4% 30-day incidence of postoperative adverse events, and a 1.7% frequency of 90-day readmissions (i.e. 2 patients with one requiring additional surgery for a deep infection) [ Tables 1 , 2 ].[ 8 ]

Table 1:

Summary of 10 studies.

Table 2:

Summary of data from 10 studies.

Three Studies Emphasized Inclusion/Exclusion Criteria for Multilevel ACDF to be Performed in ASC

Three studies emphasized careful patient selection utilizing multiple “inclusion” and “exclusion criteria” for performing multilevel ACDF/mixed procedures in ASC [ Tables 1 2 ].[ 6 , 7 , 10 ] When Vaishnavi et al. (2019) compared outcomes for 2-level ACDF performed in ASC vs. in inpatient facilities, they emphasized major differences between the two populations; ASC patients had lower BMI (i.e. averaging 27.3 vs. > 30.4 for inpatients), and lower ASA Grades (i.e. I-II for ASC vs. > II for ASA for inpatients).[ 10 ] For McGirt et al. (2020) 2000 consecutive 1-3 level ACDF performed in ASC using 4 hr. PACU windows, they found that: “...surgeons can safely perform ACDFs in an ASC utilizing patient selection criteria and perioperative management protocols...”; they did note, however, higher morbidity rates for multilevel procedures [ Table 1 ].[ 6 ] Similarly, Monk et al, (2023) found that 1-2 level ACDF performed in ASC vs. a propensity matched cohort of inpatients exhibited similar “improvement and outcomes”, largely attributed to patient selection.[ 7 ]

Medicolegal Suits Due to Ignoring Exclusion Criteria for ACDF Surgery Performed in ASC

Experience with two medicolegal suits reviewed by this neurosurgeon highlight how critical it is to follow exclusion criteria when choosing to performing ACDF in ASC. In the first case, a morbidly obese alcoholic underwent a 1-level ACDF in an ASC; within 2 hours of discharge to home, he sustained a fatal cardiorespiratory arrest. A second patient, over 65 years of age, underwent a multilevel ACDF in an ASC, and was discharged home within less than the requisite 4 hour postoperative observation window despite an excessive amount of Jackson-Pratt drainage. He too sustained a cardiac arrest at home, but remained vegetative for over 1 year before expiration. Notably, there must be many other “unreported” cases of ACDF being negligently performed in ASC (i.e. failure to follow “exclusion criteria”) resulting in irrevocable patient harm.

Nearly Comparable Morbidity Rates for 1-Level vs. Multilevel ACDF Performed in ASC: This Makes No Sense as “Less (Surgery) Should Be Less (Morbidity)”

First, Documentation of Safe Performance of 1-Level and/ or Multilevel ACDF in ASC

Several studies documented the relative safety of performing 1-level vs. multilevel ACDF in ASC (same day discharges) [ Tables 1 , 2 ].[ 1 , 2 , 4 , 9 , 10 ] Garringer et al (2010) concluded that the 645 1-level ACDF performed in ASC were safely performed; there were no deaths, 2 (0.3%) developed immediate postoperative epidural hematomas (i.e. within the 4 hour postoperative observation window), while 6% were readmitted within 48 postoperative hours.[ 4 ] Adamson et al. (2016) concluded that the 1000 1-2 level ACDF performed in ASC were also safely performed “without compromising surgical safety” vs. 484 performed as inpatients.[ 1 ] Arshi et al. (2018) just noted that patients undergoing 1-2 level ACDF in ASC had higher postoperative acute renal failure rates (i.e. likely reflecting suboptimal intraoperative blood pressure management by anesthesia).[ 2 ] Although Vaishnav et al. (2019) noted that patients selected for 1-2 level ACDF in ASC had lower BMI and lesser ASA Grades vs. the inpatients, they nevertheless concluded that both groups demonstrated comparable short and long-term outcomes [ Tables 1 , 2 ].[ 10 ] Safee et al. (2021) looked at 470 ACDF performed in ASC vs. outpatient hospital centers (i.e. 23 hours stays) vs. inpatient procedures [ Tables 1 , 2 ]. [ 9 ] Although the same day or overnight procedures were shorter, and involved less blood loss vs. inpatients, all 3 demonstrated comparable perioperative adverse events, and 30-day readmission rates [ Tables 1 , 2 ].[ 9 ]

Rates for Multilevel ACDF Compared with Single-Level ACDF Makes No Sense

Despite differences in immediate postoperative hospital transfer rates for 1-level vs. multilevel ACDF performed in ASC (i.e. 0-6% for 1-level vs. 0-0.8% for multilevel procedures), our analysis of these studies showed nearly comparable 30-day (1.9-2.4%), and 90 day ED visits, readmissions, and reoperation rates (1.7-2.2%) [ Tables 1 , 2 ].[ 1 , 4 - 7 , 9 , 10 ] Reasons for these differences/disparities likely included; small sample sizes (i.e. for some studies), the inclusion of fewer centers (i.e. some single center studies), and their use of less stringent criteria for readmissions [ Tables 1 , 2 ].[ 2 , 4 , 5 , 6 , 7 ] For example, Garringer et al. (2010) reported a 6% readmission rate within 48 postoperative hours for 645 patients undergoing 1-level ACDF; 80% were for pain/nausea alone (i.e. example of less stringent criteria).[ 4 ] Gennari et al. sample included just 30 patients operated on at just one facility; 1 (3%) patient required hospital transfer for a new postoperative neurological deficit, while 2 (7%) required rehospitalization on postoperative day 1 for dysphagia (i.e. small sample size in one institution).[ 5 ] Rossi et al. (2019) studied just 119 Medicare patients (i.e. undergoing 1-level ACDF (103 patients) vs. 2-level ACDF (15 patients)) who required no immediate postoperative hospital transfers, while 2.4% needed 30-day ED visits for adverse events, and 1.7% required 90-day readmissions (i.e. including 1 reoperation for a surgical site infection-small number series).[ 8 ] Alternatively, several multilevel ACDF studies showed just 0-0.8% immediate postoperative readmission rates; these were substantially larger series and involved multliple centers (i.e. Arshi et al. 1215 1-2 ACDF in ASC, McGirt et al. 2000 1-2 level ACDF in ASC, Monk et al. 520 1-2 level ACDF in ASC).[ 2 , 6 , 7 ]

Difficulty Comparing Variable Study Designs Involving Different Patient Populations

We had difficulty comparing results of 1-level vs. multilevel ACDF performed in ASC due to marked variability in study designs resulting in operations being performed on fundamentally different patient populations.

Results of 1-level ACDF Performed in ASC

Two studies looked specifically at the results of 1-level ACDF performed in ASC [ Tables 1 , 2 ].[ 4 , 5 ] In Garringer et al. (2010), of 645 1-level ACDF performed in ASC, they found 6% of patients required postoperative hospitalization within 48 postoperative hrs.; 2 (0.3%) patients required surgery for epidural hematomas picked up within the 4 hour postoperative anesthesia care unit (PACU) stays [ Tables 1 , 2 ].[ 4 ] For Gennari et al. (2018) 30 patients undergoing 1-level ACDF in an ASC, 1 (3%) patient developed a new postoperative neurological deficit discovered within the 7.5 hr. PACU observation window, and required immediate hospitalization/reoperation, while 2 (7%) other patients were hospitalized on post-discharge day 1 for dysphagia [ Table 1 ].[ 5 ]

Results for 1 to 2-level ACDF Performed in ASC

Several series looked at results for patients undergoing 1-2 level ACDF in ASC [ Tables 1 , 2 ].[ 1 , 2 , 8 ] Using a 4 hr. ASC PACU observation window, Adamson et al. (2016) evaluated 1000 patients undergoing 1-2 level ACDF in an ASC; 8 (0.8%) adverse events required immediate hospital transfers (i.e. 3 for pain, 1 hematoma, 2 for chest pain, 1 with a cerebrospinal fluid leak, and 1 new neurological deficit/ reoperation).[ 1 ] Nevertheless, the 30-day (2.2%) and 90-day (2.2%) readmission rates were nearly comparable to those for 484 patients undergoing inpatient procedures.[ 1 ] Arshi et al. (2018), utilizing PearlDiver Records, studied reoperation rates for 1-2 level ACDF performed in ASC (1215 patients) vs. in inpatient settings (10,964 patients); those undergoing ASC surgery were more likely to warrant secondary posterior revisions within 6 to 12 postoperative months, or repeat ACDF within the first postoperative year [ Tables 1 , 2 ].[ 2 ] Evaluating 1-2 level ACDF performed in ASC involving 119 Medicare patients (i.e. 103 1-level/15 2-level, including patients in ASA Grades I-III) using 4 hrs. PACU stays, Rossi et al. (2019) found none required immediate postoperative hospital transfers, but the 30-day postoperative morbidity was 2.4%, while the 90-day postoperative readmission rate was 1.7%, similar to the numbers cited above in Adamson’s Series [ Tables 1 , 2 ].[ 1 , 8 ]

Results for 2-level ACDF Performed in ASC vs. Inpatient

Vaishnav et al. (2019) compared outcomes for 2-level ACDF performed in ASC vs. as inpatients; despite significant differences including lower BMI and lower ASA scores for ASC patients, they found similar outcomes at 6 postoperative weeks and 6 postoperative months [ Tables 1 , 2 ],[ 10 ]

Results of 1 to 3-level ACDF Performed in ASC

When McGirt et al. (2020) performed 2000 consecutive 1-3 level ACDF in an ASC utilizing a 4 h. PACU observation window, 10 (0.5%) patients required immediate postoperative hospital transfers for; 2 hematomas, 2 with pain alone, 1 CSF leak, and 5 medical adverse events [ Tables 1 , 2 ].[ 6 ] Further, the 30-day readmission rate was 1.9% (i.e. 6 patients required reoperations).

Concern About More Complex Spine Surgery Being Performed in ASC

Baird et al. (2014) observed that 84.2% of spine surgeons now work in ASC, with 49.1% being invested in these facilities [ Tables 1 , 2 ].[ 3 ] They additionally found a “trend” for invested spine surgeons to perform increasingly complicated operations in these facilities. Further, they were concerned that at least some of these ASC procedures should still be done in hospitals; “...where a patient may have better access to emergency care.”

CONCLUSION

Different study designs showed nearly comparable outcomes for patients undergoing 1-level vs. multilevel ACDF performed in ASC. Nevertheless, common sense should dictate that “less (surgery) should be less (morbidity)”, meaning 1-level ACDF should involve less surgical risk vs. multilevel procedures performed in ASC.[ 6 ]

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

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