Lateral versus prone robot-assisted percutaneous pedicle screw placement: a CT-based comparative assessment of accuracy

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  • 1 Department of Neurosurgery, MedStar Georgetown University Hospital, Washington, DC;
  • | 2 Georgetown University School of Medicine, Washington, DC; and
  • | 3 Department of Radiology, MedStar Georgetown University Hospital, Washington, DC
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OBJECTIVE

Single-position lateral lumbar interbody fusion (SP-LLIF) has recently gained significant popularity due to increased operative efficiency, but it remains technically challenging. Robot-assisted percutaneous pedicle screw (RA-PPS) placement can facilitate screw placement in the lateral position. The authors have reported their initial experience with SP-LLIF with RA-PPS placement in the lateral position, and they have compared this accuracy with that of RA-PPS placement in the prone position.

METHODS

The authors reviewed prospectively collected data from their first 100 lateral-position RA-PPSs. The authors graded screw accuracy on CT and compared it to the accuracy of all prone-position RA-PPS procedures during the same time period. The authors analyzed the effect of several demographic and perioperative metrics, as a whole and specifically for lateral-position RA-PPS placement.

RESULTS

The authors placed 99 lateral-position RA-PPSs by using the ExcelsiusGPS robotic platform in the first 18 consecutive patients who underwent SP-LLIF with postoperative CT imaging; these patients were compared with 346 prone-position RA-PPSs that were placed in the first consecutive 64 patients during the same time period. All screws were placed at L1 to S1. Overall, the lateral group had 14 breaches (14.1%) and the prone group had 25 breaches (7.2%) (p = 0.032). The lateral group had 5 breaches (5.1%) greater than 2 mm (grade C or worse), and the prone group had 4 (1.2%) (p = 0.015). The operative level had an effect on the breach rate, with breach rates (grade C or worse) of 7.1% at L3 and 2.8% at L4. Most breaches were grade B (< 2 mm) and lateral, and no breach had clinical sequelae or required revision. Within the lateral group, multivariate regression analysis demonstrated that BMI and number of levels affected accuracy, but the side that was positioned up or down did not.

CONCLUSIONS

RA-PPSs can improve the feasibility of SP-LLIF. Spine surgeons should be cautious and selective with this technique owing to decreased accuracy in the lateral position, particularly in obese patients. Further studies should compare SP-LLIF techniques performed while the patient is in the prone and lateral positions.

ABBREVIATIONS

ALIF = anterior lumbar interbody fusion; LLIF = lateral lumbar interbody fusion; PPS = percutaneous pedicle screw; RA-PPS = robot-assisted percutaneous pedicle screw; SP-LLIF = single-position lateral lumbar interbody fusion; TLIF = transforaminal lumbar interbody fusion.

OBJECTIVE

Single-position lateral lumbar interbody fusion (SP-LLIF) has recently gained significant popularity due to increased operative efficiency, but it remains technically challenging. Robot-assisted percutaneous pedicle screw (RA-PPS) placement can facilitate screw placement in the lateral position. The authors have reported their initial experience with SP-LLIF with RA-PPS placement in the lateral position, and they have compared this accuracy with that of RA-PPS placement in the prone position.

METHODS

The authors reviewed prospectively collected data from their first 100 lateral-position RA-PPSs. The authors graded screw accuracy on CT and compared it to the accuracy of all prone-position RA-PPS procedures during the same time period. The authors analyzed the effect of several demographic and perioperative metrics, as a whole and specifically for lateral-position RA-PPS placement.

RESULTS

The authors placed 99 lateral-position RA-PPSs by using the ExcelsiusGPS robotic platform in the first 18 consecutive patients who underwent SP-LLIF with postoperative CT imaging; these patients were compared with 346 prone-position RA-PPSs that were placed in the first consecutive 64 patients during the same time period. All screws were placed at L1 to S1. Overall, the lateral group had 14 breaches (14.1%) and the prone group had 25 breaches (7.2%) (p = 0.032). The lateral group had 5 breaches (5.1%) greater than 2 mm (grade C or worse), and the prone group had 4 (1.2%) (p = 0.015). The operative level had an effect on the breach rate, with breach rates (grade C or worse) of 7.1% at L3 and 2.8% at L4. Most breaches were grade B (< 2 mm) and lateral, and no breach had clinical sequelae or required revision. Within the lateral group, multivariate regression analysis demonstrated that BMI and number of levels affected accuracy, but the side that was positioned up or down did not.

CONCLUSIONS

RA-PPSs can improve the feasibility of SP-LLIF. Spine surgeons should be cautious and selective with this technique owing to decreased accuracy in the lateral position, particularly in obese patients. Further studies should compare SP-LLIF techniques performed while the patient is in the prone and lateral positions.

Percutaneous pedicle screw (PPS) placement serves to stabilize the spine during lumbar interbody fusion.14 Minimally invasive techniques, including PPSs and lateral lumbar interbody fusion (LLIF), offer the advantages of reduced muscle dissection, reduced blood loss, and enhanced recovery in comparison with open approaches.57 Furthermore, LLIF offers the ability to insert larger interbody spacers, reduce operative time, and potentially result in fewer complications than open interbody fusion techniques.810 If posterior instrumentation in conjunction with LLIF is necessary, significant time and resources are spent repositioning and redraping the patient from the lateral decubitus to the prone position to facilitate PPS placement.1012

A major concern for single-position lateral access surgery is the technical difficulty of placing bilateral pedicle screws in a patient in the lateral position.10,13 The recent emergence of robot-assisted navigation has facilitated PPS placement while the patient remains in the lateral decubitus position, obviating the need for repositioning and redraping. Compared with screws placed with existing techniques, robotically placed screws have been shown to maintain a high level of accuracy.1417 Data have been published on the overall robotic accuracy rates of PPS placement in interbody fusion,14,15 but to our knowledge only one study has specifically examined the accuracy of robotically placed PPSs used in LLIF.9 Although saving time and resources offers a strong incentive for the use of robotic navigation in these cases, accuracy and safety should not be compromised in the process. This necessitates an evaluation of the accuracy of PPS placement in LLIF performed with robotic assistance.

In the current study, we have reported our experience using the ExcelsiusGPS robotic navigation system (Globus Medical) for single-position LLIF (SP-LLIF). We evaluated the accuracy of pedicle screws placed in the lateral decubitus position for patients who underwent LLIF, and we compared this accuracy with that of robot-assisted PPS (RA-PPS) placement in the prone position. Verification of accuracy using this technique would support more widespread adoption of robotic navigation in an effort to reduce operative times and expenditures, thereby benefitting the patient and the healthcare system. To our knowledge, this is the first study in the literature to directly compare the accuracy of RA-PPS placement in the lateral position to that performed in the prone position.

Methods

We conducted a single-center review of prospectively collected data from our first 100 RA-PPSs placed during lateral-position SP-LLIF, as well as all other patients who underwent RA-PPS placement in the prone position during the same period. The study design was similar to that of our previous publication on RA-PPS accuracy.14

All patients underwent preoperative CT of the lumbar spine, and postoperative CT was part of our routine protocol. Patients who did not tolerate or refused postoperative imaging were excluded from our study. The two senior authors (F.A.S. and J.M.V.), who are fellowship-trained minimally invasive spine neurosurgeons, performed all procedures using the ExcelsiusGPS robotic navigation platform. Globus Medical was not involved, financially or otherwise, in the design or implementation of this study.

Minimally invasive instrumented interbody fusion procedures were performed on all patients to treat degenerative spine conditions, including spondylolisthesis, spondylosis, disc degeneration, and spinal deformity, after a trial of conservative management. One patient was treated for a metastatic vertebral body lesion. No patients were treated for traumatic or infectious pathologies. We used PPSs to instrument transforaminal lumbar interbody fusion (TLIF), LLIF, or anterior lumbar interbody fusion (ALIF). Patients who underwent TLIF underwent PPS placement in the prone position, those who underwent LLIF underwent PPS placement in a single stage in the lateral position, and those who underwent ALIF underwent PPS placement in the second stage of surgery in the prone position. We placed PPSs prior to the interbody device in all patients. All aspects of LLIF, including screw placement, were performed completely with the patient in the lateral position. After collecting these data, we compared the accuracy of RA-PPS placement during SP-LLIF with the patient in the lateral position to that of RA-PPS placement in the prone position. Within the SP-LLIF group, we also compared the accuracy of screw placement between screws placed on the side positioned up and those placed on the side positioned down.

Operative Technique

Our technique for RA-PPS placement was described in a previous publication.14 Briefly, we obtain a preoperative CT scan and upload it to the robot’s navigation platform. We plan the screw trajectories using the navigation software. We position the patient prone on an open Jackson table; for LLIF, the patient is in the lateral decubitus position on a standard operating table. We prepare and drape the surgical site, then affix the reference and surveillance arrays to the iliac crest. We use the C-arm with the image calibration plate to merge the preoperative CT scan and anteroposterior and lateral images of each vertebra of interest. Then, we drive the robotic arm to each selected screw trajectory. We make appropriate skin incisions and then load the surgical instruments through the arm in a sequential fashion, starting with a scalpel to incise the fascia, followed by a high-speed burr to create a pilot hole and a tap to prepare the tract. Finally, we place the screw through the robotic arm. We confirm accurate screw placement with fluoroscopy. We insert and secure the rods after interbody fusion is performed.

For SP-LLIF, the patient is in the right or left lateral decubitus position depending on the imaging findings and/or surgeon preference (Fig. 1). The knees are flexed to relax the psoas muscle, and the patient is secured with tape to the operating table in a true lateral position. We ensure that the patient is positioned as close as safely possible to the posterior edge of the operating table to allow room for the robotic arm to reach the down-side screw trajectories. The reference and surveillance arrays are both secured to the up-side iliac crest (Fig. 2). Registration and screw placement are performed as described above. The operating table is then flexed to help gain access to the operative levels between the iliac crest and ribs. LLIF is performed in a standard fashion. Afterward, the operating table is leveled, followed by rod insertion and final tightening of the set caps.

FIG. 1.
FIG. 1.

Operating room setup. The patient is in the lateral decubitus position. This view from the location of the navigation camera shows the reference and surveillance arrays secured to the patient’s iliac crest, the C-arm with the calibration plate in front of the patient, the robot behind the patient, and the C-arm screen at the head of the table. Figure is available in color online only.

FIG. 2.
FIG. 2.

Placement of the reference and surveillance arrays to the patient’s up-side iliac crest. Figure is available in color online only.

Assessment of Screw Accuracy

We obtained postoperative CT scans, which were independently reviewed by a neuroradiologist (A.S.) who was blinded to the fusion operation performed. She provided the screw accuracy grades based on the Gertzbein-Robbins classification grading system (Table 1).

TABLE 1.

Gertzbein-Robbins classification grading system

GradeScrew Position Relative to Pedicle
ACompletely w/in pedicle
BBreach <2 mm
CBreach 2–4 mm
DBreach 4–6 mm
EBreach >6 mm

Based on Gertzbein SD, Robbins SE. Accuracy of pedicular screw placement in vivo. Spine (Phila Pa 1976). 1990;15(1):11-14 and Fan Y, Du JP, Liu JJ, Zhang JN, Liu SC, Hao DJ. Radiological and clinical differences among three assisted technologies in pedicle screw fixation of adult degenerative scoliosis. Sci Rep. 2018;8(1):890.

Data Analysis

The data analysis was similar to that of our previous study on RA-PPS accuracy.14 After collecting demographic, perioperative, and imaging data for each patient, we calculated descriptive statistics for all variables using Microsoft Excel. We then used logistic regression analysis to compare continuous independent variables such as screw accuracy grades (the dependent variable), and we used multiple 2-way tables with chi-square analysis to compare categorical independent variables with screw accuracy. Afterward, we used chi-square analysis to compare the screw accuracy grades of RA-PPS placement during SP-LLIF with those of prone RA-PPS placement. Finally, we used multivariate regression analysis to identify independent variables that affected the accuracy of RA-PPS placement during SP-LLIF, followed by logistic regression or chi-square analysis for in-depth analysis of these individual variables. All statistical analyses were performed using Stata (StataCorp), with a prospectively determined p value < 0.05 taken to indicate a significant difference for all analyses.

Study Design and Ethics

This study adheres to the Preferred Reporting of Case Series in Surgery (PROCESS) guidelines. This study was approved by our institutional review board and did not require patient consent due to the retrospective nature of the analysis.

Results

Demographic Data Analysis

In this study, we placed 445 RA-PPSs using the ExcelsiusGPS robotic navigation platform in the first 82 consecutive patients with available postoperative CT scans. Of those screws, 99 RA-PPSs were placed in 18 patients in the lateral position, and 346 RA-PPSs were placed in 64 patients in the prone position. One screw was not placed in the last patient in the lateral position owing to small pedicle size and difficulty accessing the pedicle. The mean (range) age was 63.8 (39–87) years, and the mean (range) BMI was 30.6 (17.4–45.9). There were 33 (40.2%) male and 49 (59.8%) female patients.

One surgeon (F.A.S.) performed 52 procedures (63.4%), and another (J.M.V.) performed 30 (36.6%). The most common diagnosis was lumbar spondylolisthesis (62.2%). Prone surgical procedures included 61 minimally invasive TLIF (95.3%) and 3 ALIF (4.7%) procedures that required the patient to be repositioned prone for screw placement. In these prone cases, the robot approached the left side of 43 (67.2%) patients and the right side of 21 (32.8%). All lateral-position surgical procedures were LLIF, and 15 (83.3%) patients were in the right lateral decubitus position and 3 (16.7%) were in the left lateral decubitus. Screws were placed in the L1 to S1 levels, and L4 (32.6%) and L5 (33.9%) were the most commonly instrumented levels. There were no major differences between the prone and lateral groups in terms of demographic characteristics. All demographic data are listed by group and in total (Table 2).

TABLE 2.

Patient demographic characteristics

VariableProneLateralTotalp Value
Patients641882NA
Age, yrs63.9 (39–87)63.5 (48–78)63.8 (39–87)0.88
Sex0.77
 Male27 (42.2)6 (33.3)33 (40.2)
 Female37 (57.8)12 (66.7)49 (59.8)
BMI, kg/m230.7 (17.4–43.0)30.2 (19.9–45.9)30.6 (17.4–45.9)0.75
Diagnosis0.24
 Spondylolisthesis40 (62.5)11 (61.1)51 (62.2)
 Spondylosis2 (3.1)0 (0.0)2 (2.4)
 Stenosis15 (23.4)4 (22.2)19 (23.2)
 Disc degeneration6 (9.4)1 (5.6)7 (8.5)
 Deformity1 (1.6)1 (5.6)2 (2.4)
 Spine tumor0 (0.0)1 (5.6)1 (1.2)
Surgeon0.10
 A39 (60.9)13 (72.2)52 (63.4)
 B25 (39.1)5 (27.8)30 (36.6)
Total screws34699445NA
Screws per level0.19
 L12 (0.6)0 (0.0)2 (0.4)
 L26 (1.7)14 (14.1)20 (4.5)
 L339 (11.3)17 (17.2)56 (12.6)
 L4109 (31.5)36 (36.4)145 (32.6)
 L5119 (34.4)32 (32.3)151 (33.9)
 S171 (20.5)0 (0.0)71 (16.0)
Levels0.16
 132 (50.0)10 (55.6)41 (50.0)
 220 (31.3)2 (11.1)23 (28.0)
 310 (15.6)6 (33.3)16 (19.5)
 41 (1.6)0 (0.0)1 (1.2)
 51 (1.6)0 (0.0)1 (1.2)
Robot approach sideNA
 Lt43 (67.2)NANA
 Rt21 (32.8)NANA
Up sideNA
 LtNA15 (83.3)NA
 RtNA3 (16.7)NA
ProcedureNA
 Minimally invasive TLIF61 (95.3)0 (0.0)61 (74.4)
 LLIF0 (0.0)18 (100.0)18 (22.0)
 ALIF3 (4.7)0 (0.0)3 (3.7)

NA = applicable.

Values are shown as number, number (%), or mean (range) unless indicated otherwise.

Accuracy Analysis

In total, 39 of 445 RA-PPSs had a breach, yielding an overall breach rate of 8.8%. Nine of those breaches were grade C or worse, yielding a significant breach rate of 2.0%. In the lateral group, 14 of 99 RA-PPSs (14.1%) had a breach, compared with 25 of 346 RA-PPSs (7.2%) in the prone group (chi-square = 4.60, p = 0.032). Five of 99 RA-PPSs (5.1%) in the lateral group had a grade C or worse breach versus 4 of 346 RA-PPSs (1.2%) in the prone group (chi-square = 5.89, p = 0.015). However, this finding was not significant when overall screw grade was compared between patients who were in the lateral position and those in the prone position (chi-square = 8.98, p = 0.061). Overall, most breaches were grade B and lateral. None of these breaches had any clinical sequelae or required revision. Breaches, as categorized by level, direction of breach, and grade, are listed in more detail (Table 3).

TABLE 3.

Robot-assisted screw accuracy in patients in the prone versus lateral position

LevelProne*LateralTotal
Breaches (total screws)Breach Rate (%)Screw LateralityBreach DirectionBreach GradeBreaches (total screws)Breach Rate (%)Screw LateralityBreach DirectionBreach GradeBreaches (total screws)Breach Rate (%)Grade C Breach (%)
L11 (2)501 (rt)1 (lateral)1 (B)0 (0)1 (2)500
L20 (6)01 (14)7.11 (lt)1 (lateral)1 (B)1 (20)50
L35 (39)12.83 (rt) & 2 (lt)4 (lateral) & 1 (medial)3 (B) & 2 (D)4 (17)23.52 (rt) & 2 (lt)2 (lateral) & 2 (medial)2 (B), 1 (C), & 1 (D)9 (56)16.17.1
L411 (109)10.19 (rt) & 2 (lt)8 (lateral) & 3 (inferior)9 (B), 1 (C), & 1 (E)7 (36)19.43 (rt) & 4 (lt)4 (lateral), 1 (medial), & 2 (superior)5 (B), 1 (C), & 1 (E)18 (145)12.42.8
L56 (119)5.02 (rt) & 4 (lt)1 (superior) & 5 (inferior)6 (B)2 (32)6.32 (rt)2 (lateral)1 (B) & 1 (C)8 (151)5.30.7
S12 (71)2.81 (rt) & 1 (lt)1 (medial) & 1 (inferior)2 (B)0 (0)2 (71)2.80
Total25 (346)7.216 (rt) & 9 (lt)13 (lateral), 2 (medial), 1 (superior), & 9 (inferior)21 (B), 1 (C), 2 (D), & 1 (E)14 (99)14.17 (rt) & 7 (rt)9 (lateral), 3 (medial), & 2 (superior)9 (B), 3 (C), 1 (D), & 1 (E)39 (445)8.8

Four of 346 patients (1.2%) had grade C or worse breach.

Five of 99 patients (5.1%) had grade C or worse breach.

Nine of 445 patients (2.0%) had grade C or worse breach.

Analysis of Factors Affecting Overall Accuracy

After our analysis of overall screw accuracy, we analyzed the effect of demographic and perioperative metrics on screw accuracy. Among continuous variables, age, number of levels fused, and BMI did not have an effect on overall grade of screw accuracy (grade A vs any breach, or grade A and B vs grade C or worse breach). The coefficients and p values of this logistic regression analysis are listed (Table 4).

TABLE 4.

Multivariate regression analysis of robot-assisted screw accuracy

VariableOverall GradeGrade A vs Any BreachGrade A+B vs Any Breach
Coefficientp ValueCoefficientp ValueCoefficientp Value
Age0.0020.524−0.0010.8800.0010.147
No. of levels0.0060.6250.0070.291−0.0010.906
BMI0.0030.4800.0010.8440.0020.062

Regarding categorical variables, sex, screw laterality, diagnosis, surgeon, approach side of the robot, and primary procedure did not significantly affect overall grade of screw accuracy (grade A vs any breach, or grade A and B vs any breach). Vertebral level had a significant effect on overall grade (chi-square = 38.67, p = 0.007) (grade A vs any breach [chi-square = 16.17, p = 0.006], and grade A and B vs any breach [chi-square = 11.14, p = 0.049]). More breaches occurred at L3 and L4. The L3 breach rate was 16.1% (7.1% for grade C or worse), and the L4 breach rate was 12.4% (2.8% for grade C or worse). Breach rates by level are listed in Table 3. We also organized cases according to time quartile and time half to determine the learning curve. Time quartile had a significant effect on overall grade (chi-square = 24.42, p = 0.018) but not breach grade (grade A vs any breach, or grade A and B vs any breach), and time half did not have any effect. The chi-square values and p values from this multiple 2-way table analysis are listed in Table 5.

TABLE 5.

Multiple 2-way table analysis of robot-assisted screw accuracy

VariableOverall GradeGrade A Breach vs Any BreachGrade A+B Breach vs Any Breach
Chi-Square Valuep ValueChi-Square Valuep ValueChi-Square Valuep Value
Sex2.800.5911.310.2530.820.365
Vertebral level38.670.007*16.170.006*11.140.049*
Screw laterality2.550.6351.280.2590.100.752
Diagnosis18.280.5699.810.0812.160.826
Surgeon4.500.3423.030.0822.000.158
Robot approach side3.510.4760.010.9860.210.649
Procedure9.900.2725.490.0645.980.050
Time quartile24.420.018*2.610.4566.010.111
Time half3.350.5000.120.7330.070.793

Statistically significant (p < 0.05).

Analysis of Factors Affecting Accuracy in the Lateral Position

We performed multivariate regression analysis of the subgroup of patients who underwent RA-PPS placement in the lateral position. This analysis identified age, BMI, number of levels, diagnosis, surgeon, and time quartile as potential factors that affect screw accuracy in the lateral position. We then performed individual regression and/or multiple 2-way table analysis to evaluate these variables. Age, diagnosis, and surgeon did not have individual significant effects on accuracy. Overall BMI did not have an effect, but BMI > 35 had a significant effect on overall screw grade (chi-square = 9.70, p = 0.046). The number of levels fused also had a significant effect on overall screw grade (chi-square = 40.72, p = 0.001) and grade A and B breach (chi-square = 13.87, p = 0.003). Interestingly, the side of the patient where the screw was placed (up vs down) did not have any effect on accuracy. Seven of 49 down-side screws breached compared with 7 of 50 up-side screws (chi-square = 2.45, p = 0.654). The coefficients and p values of the subgroup analysis are listed in Table 6.

TABLE 6.

Analysis of robot-assisted screws placed with the patient in the lateral position

VariableOverall GradeGrade A vs Any BreachGrade A+B vs Any Breach
Coefficient/ Chi-Square Valuep ValueCoefficient/ Chi-Square Valuep ValueCoefficient/ Chi-Square Valuep Value
Age−0.0060.459−0.0060.1440.0010.865
BMI0.0020.855−0.0010.8160.0050.184
BMI >35 kg/m29.700.046*0.010.9792.610.106
No. of levels40.720.001*5.490.13913.870.003*
Diagnosis21.950.1453.710.4473.270.513
Surgeon2.030.7311.210.2721.880.171
Time quartile16.950.1520.330.9537.540.056
Up-side vs down-side screw placement2.450.6540.010.9670.190.663

Statistically significant (p < 0.05).

Discussion

Placement of PPSs with the patient in the lateral position has been used to supplement LLIF procedures and to decrease operative times and utilization of resources.10,11,13,1821 However, there are concerns regarding the accuracy and technical difficulties of placing these screws with the patient in the lateral position. Robotic assistance and navigation may mitigate these concerns. In this study, we have reported our initial experience with RA-PPS placement with the patient in the lateral position and compared the accuracy of this technique to that of a series of patients who underwent RA-PPS placement in the prone position.

Accuracy

Overall, the accuracy of RA-PPSs in our study was similar to that previously reported by other series in the literature.2834 We had an overall breach rate of 8.8% and a significant breach rate of 2.0% for all screws. Screws placed while the patient was in the lateral position had higher overall and significant breach rates (14.1% and 5.1%, respectively) than those placed while the patient was in the prone position (7.2% and 1.2%). Most breaches were in the lateral direction in both groups: 13 of 25 in the prone group, and 9 of 14 in the lateral group. However, none of these breaches resulted in clinical sequelae or required repositioning. Therefore, although RA-PPSs placed in the lateral position were less accurate than those placed in the prone position, there were no clinical effects and therefore use of the lateral position remains a viable and effective technique to reduce operative time and resources. There were more breaches at L3 and L4 than at other levels, but the reason for this finding remains unclear. The time quartile in which the screws were placed had an effect on accuracy, but time half did not, indicating that we do not have enough data to comment on the learning curve.

Looking specifically at the lateral group, we found that BMI and number of fused levels influenced accuracy. Other series have reported the negative effects of BMI on accuracy in patients in the lateral and prone positions.15 This may reflect both the increased difficulty in navigation registration and the stability of the patient in either position on the operating table. Furthermore, with an increasing number of instrumented levels, one would expect an increase in the motion of the patient, which may decrease the accuracy of navigation. Interestingly, contrary to other studies,18 sidedness did not influence accuracy in our study. It has been theorized that increased mobility of the "top" or "up-side" of the patient may decrease screw accuracy on this side while the patient is in the lateral position and increase risk of lateral breach, but we did not observe this phenomenon in our series. This may have been counterbalanced by the difficulty of navigating instruments on the "bottom" or "down-side" of the patient. Early in our experience, we had some difficulty with the down-side of the patient because of the limited angle available to place these screws due to the proximity of the operating table. We sought to mitigate this difficulty by planning screws with less lateral to medial angulation (i.e., less triangulation) in order to avoid steep upward angles, as well as by positioning the patient closer to the edge of the table to avoid contact between the instruments and the operating table. Nevertheless, on the basis of these data, we advise caution when considering this single-position lateral approach for longer constructs and patients with BMI > 35.

Several studies have investigated the proposed advantages of the single-position lateral approach and have demonstrated decreased operative time and blood loss without compromised restoration of lumbar lordosis.10,11,13,1821 Our findings further support those in the literature because, to our knowledge, this is the largest study to specifically compare the accuracy of RA-PPS placement while the patient is in the lateral position versus that of screw placement while the patient is in the prone position. Huntsman et al. placed 328 robot-assisted screws in the lateral position and reported an accuracy rate of 98%.9 However, they utilized intraoperative fluoroscopic imaging rather than dedicated postoperative CT imaging to assess accuracy, which likely underestimated the breach rate. Ouchida et al. compared screws placed in the lateral position to those placed in the prone position in 102 patients who underwent intraoperative navigation with an O-arm.11 They reported a significant (> 2 mm) breach rate of 1.8% in the lateral position and a significant breach rate of 4.0% in the prone position, which were not significantly different. No clinical sequelae related to screw placement were noted. The difference in the accuracy rates between this study and ours may be explained by their use of O-arm navigation, whereas we used fused preoperative CT and intraoperative fluoroscopy for robotic navigation. Hiyama et al. reported a breach rate of 4.1% for screws placed in both the lateral and prone positions with fluoroscopic guidance.18 This difference in navigation technique confounds comparison to our study. Blizzard et al. reported a breach rate of 5.1% for 300 screws placed in the lateral position with fluoroscopic guidance but without comparison to screws placed in the prone position.12 Lastly, Godzik et al. reported a breach rate of 3.4% for 116 screws placed in both lateral and prone positions, without comparison between groups.15 Ultimately, our study demonstrated a higher breach rate for screws placed in the lateral position than other studies in the literature; however, our study directly compared screws in the lateral and prone positions placed with robotic assistance and provided a more robust analysis by using specific screw accuracy grades and a larger number of screws. Additionally, the clinical outcomes of these studies are similar because no clinical sequelae or screws required repositioning. Thus, these studies are consistent in their support of the safety and feasibility of the single-position lateral technique.

Comparison With the Single-Position Prone Lateral Approach

The single-position prone lateral approach is a relatively new technique that is gaining significant popularity among spine surgeons. Several recent studies have touted its advantages, including reduced operative time, better restoration of lordosis, and easy capability to perform simultaneous posterior approaches for decompression, extension of fusion, or longer constructs.2227 However, there are several limitations to this approach. The proposed increase in restoration of lumbar lordosis compared with that achieved in the lateral position is limited to segmental lordosis and has a limited effect on overall lumbar lordosis.24 Difficulties in patient positioning—including inability to break the operating table to widen the space between the ribs and iliac crest, patient movement during disc preparation and implant insertion, obstruction of the working corridor by the pads of the operating table, anterior migration of the retractor due to gravity, and difficulty maintaining an orthogonal trajectory to the disc space—can limit the efficacy and increase the difficulty of this technique. Nevertheless, there are various means of addressing these limitations due to positioning, such as the use of lateral and/or anterior bolsters, that would make this a viable and powerful technique. With these caveats in mind, we suggest using the single-position lateral approach for routine LLIF cases that require only PPS fixation. In these cases, LLIF is the critical part of the procedure and should not be complicated by prone positioning, especially if the PPS portion can be facilitated with robotic assistance. The prone lateral or lateral-then-prone approaches should be used for patients who require more extensive posterior work, patients with deformity, patients with a history of surgery, or patients with BMI > 35.

Limitations

Our study had several limitations. Although our series is larger than many similar studies in the literature, a larger sample size would be better suited for detecting small statistically significant differences between groups. The retrospective nature of our study may potentially introduce selection and other biases. We did not consistently obtain postoperative standing radiographs to document lumbar lordosis and other radiographic parameters. A comparison of RA-PPSs placed in the lateral position with a control group of screws placed with fluoroscopic guidance would have been useful. We utilized fluoroscopy to register and confirm screw placement in an effort to reduce operative time and utilization of resources, but we realize that use of intraoperative CT may further improve breach rates. Use of intraoperative CT would also allow for comparison of CT navigation techniques. Additionally, direct comparison of the outcomes of the SP-LLIF and prone lateral approaches would make for an interesting discussion. Lastly, tracking operative time and costs would have further strengthened this study.

Conclusions

Placement of RA-PPSs in patients in the lateral position had a significantly higher overall breach rate than screws placed with the patient in the prone position. Although all breaches were clinically asymptomatic, increased BMI and greater number of fused levels negatively impacted accuracy in the lateral cohort. Despite lower accuracy rates, RA-PPS placement can improve the feasibility of SP-LLIF. Spine surgeons should be cautious and selective with this technique, particularly in obese patients. Further studies should compare SP-LLIF techniques performed in the prone and lateral positions to aid surgeon decision-making regarding these two approaches.

Disclosures

Dr. Sandhu is a consultant for Globus Medical, Stryker, and Spine Wave and receives royalties from Globus Medical (unrelated to the robotic platform), Stryker, and Spineart. Dr. Voyadzis is a consultant for Globus Medical.

Author Contributions

Conception and design: Fayed, Voyadzis, Sandhu. Acquisition of data: Fayed, Triano, Weitz, Sayah. Analysis and interpretation of data: Fayed, Tai, Sayah, Voyadzis, Sandhu. Drafting the article: Fayed, Tai, Triano, Weitz. Critically revising the article: Fayed, Tai, Voyadzis, Sandhu. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Fayed. Statistical analysis: Fayed. Study supervision: Voyadzis, Sandhu.

Supplemental Information

Previous Presentations

This abstract was presented in an oral presentation during the Top Abstracts session and received the Charles Kuntz Scholar Award for excellence in neurosurgical research at the AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves Spine Summit, San Diego, CA, July 29, 2021.

References

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    Foley KT, Holly LT, Schwender JD. Minimally invasive lumbar fusion. Spine (Phila Pa 1976). 2003;28(15)(suppl):S26S35.

  • 2

    Holly LT, Schwender JD, Rouben DP, Foley KT. Minimally invasive transforaminal lumbar interbody fusion: indications, technique, and complications. Neurosurg Focus. 2006;20(3):E6.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Isaacs RE, Podichetty VK, Santiago P, et al. Minimally invasive microendoscopy-assisted transforaminal lumbar interbody fusion with instrumentation. J Neurosurg Spine. 2005;3(2):98105.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Spitz SM, Sandhu FA, Voyadzis JM. Percutaneous "K-wireless" pedicle screw fixation technique: an evaluation of the initial experience of 100 screws with assessment of accuracy, radiation exposure, and procedure time. J Neurosurg Spine. 2015;22(4):422431.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Kim DY, Lee SH, Chung SK, Lee HY. Comparison of multifidus muscle atrophy and trunk extension muscle strength: percutaneous versus open pedicle screw fixation. Spine (Phila Pa 1976). 2005;30(1):123129.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6

    Park Y, Ha JW. Comparison of one-level posterior lumbar interbody fusion performed with a minimally invasive approach or a traditional open approach. Spine (Phila Pa 1976). 2007;32(5):537543.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7

    Stevens KJ, Spenciner DB, Griffiths KL, et al. Comparison of minimally invasive and conventional open posterolateral lumbar fusion using magnetic resonance imaging and retraction pressure studies. J Spinal Disord Tech. 2006;19(2):7786.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Voyadzis JM, Anaizi AN. Minimally invasive lumbar transfacet screw fixation in the lateral decubitus position after extreme lateral interbody fusion: a technique and feasibility study. J Spinal Disord Tech. 2013;26(2):98106.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Huntsman KT, Riggleman JR, Ahrendtsen LA, Ledonio CG. Navigated robot-guided pedicle screws placed successfully in single-position lateral lumbar interbody fusion. J Robot Surg. 2020;14(4):643647.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Ziino C, Konopka JA, Ajiboye RM, Ledesma JB, Koltsov JCB, Cheng I. Single position versus lateral-then-prone positioning for lateral interbody fusion and pedicle screw fixation. J Spine Surg. 2018;4(4):717724.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Ouchida J, Kanemura T, Satake K, Nakashima H, Ishikawa Y, Imagama S. Simultaneous single-position lateral interbody fusion and percutaneous pedicle screw fixation using O-arm-based navigation reduces the occupancy time of the operating room. Eur Spine J. 2020;29(6):12771286.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Blizzard DJ, Thomas JA. MIS single-position lateral and oblique lateral lumbar interbody fusion and bilateral pedicle screw fixation: feasibility and perioperative results. Spine (Phila Pa 1976). 2018;43(6):440446.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13

    Hiyama A, Sakai D, Sato M, Watanabe M. The analysis of percutaneous pedicle screw technique with guide wire-less in lateral decubitus position following extreme lateral interbody fusion. J Orthop Surg Res. 2019;14(1):304.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Fayed I, Tai A, Triano M, et al. Robot-assisted percutaneous pedicle screw placement: evaluation of accuracy of the first 100 screws and comparison with cohort of fluoroscopy-guided screws. World Neurosurg. 2020;143:e492e502.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Godzik J, Walker CT, Hartman C, et al. A quantitative assessment of the accuracy and reliability of robotically guided percutaneous pedicle screw placement: technique and application accuracy. Oper Neurosurg (Hagerstown). 2019;17(4):389395.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16

    Overley SC, Cho SK, Mehta AI, Arnold PM. Navigation and robotics in spinal surgery: where are we now?. Neurosurgery. 2017;80(3S):S86S99.

  • 17

    Jain D, Manning J, Lord E, et al. Initial single-institution experience with a novel robotic-navigation system for thoracolumbar pedicle screw and pelvic screw placement with 643 screws. Int J Spine Surg. 2019;13(5):459463.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Hiyama A, Katoh H, Sakai D, Sato M, Tanaka M, Watanabe M. Accuracy of percutaneous pedicle screw placement after single-position versus dual-position insertion for lateral interbody fusion and pedicle screw fixation using fluoroscopy. Asian Spine J. Published online May 4, 2021. doi: 10.31616/asj.2020.0526

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Hiyama A, Katoh H, Sakai D, Sato M, Tanaka M, Watanabe M. Comparison of radiological changes after single-position versus dual- position for lateral interbody fusion and pedicle screw fixation. BMC Musculoskelet Disord. 2019;20(1):601.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Drazin D, Kim TT, Johnson JP. Simultaneous lateral interbody fusion and posterior percutaneous instrumentation: early experience and technical considerations. BioMed Res Int. 2015;2015:458284.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Buckland AJ, Ashayeri K, Leon C, et al. Single position circumferential fusion improves operative efficiency, reduces complications and length of stay compared with traditional circumferential fusion. Spine J. 2021;21(5):810820.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Lamartina C, Berjano P. Prone single-position extreme lateral interbody fusion (Pro-XLIF): preliminary results. Eur Spine J. 2020;29(suppl 1):613.

  • 23

    Martirosyan NL, Uribe JS, Randolph BM, Buchanan RI. Prone lateral lumbar interbody fusion: case report and technical note. World Neurosurg. 2020;144:170177.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Walker CT, Farber SH, Gandhi S, Godzik J, Turner JD, Uribe JS. Single-position prone lateral interbody fusion improves segmental lordosis in lumbar spondylolisthesis. World Neurosurg. 2021;151:e786e792.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Pimenta L, Taylor WR, Stone LE, Wali AR, Santiago-Dieppa DR. Prone transpsoas technique for simultaneous single-position access to the anterior and posterior lumbar spine. Oper Neurosurg (Hagerstown). 2020;20(1):E5E12.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26

    Pimenta L, Amaral R, Taylor W, et al. The prone transpsoas technique: preliminary radiographic results of a multicenter experience. Eur Spine J. 2021;30(1):108113.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27

    Godzik J, Ohiorhenuan IE, Xu DS, et al. Single-position prone lateral approach: cadaveric feasibility study and early clinical experience. Neurosurg Focus. 2020;49(3):E15.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Staartjes VE, Klukowska AM, Schröder ML. Pedicle screw revision in robot-guided, navigated, and freehand thoracolumbar instrumentation: a systematic review and meta-analysis. World Neurosurg. 2018;116:433443.e8.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Kantelhardt SR, Martinez R, Baerwinkel S, Burger R, Giese A, Rohde V. Perioperative course and accuracy of screw positioning in conventional, open robotic-guided and percutaneous robotic-guided, pedicle screw placement. Eur Spine J. 2011;20:860868.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Laudato PA, Pierzchala K, Schizas C. Pedicle screw insertion accuracy using O-Arm, robotic guidance, or freehand technique: a comparative Study. Spine (Phila Pa 1976). 2018;43(6):E373E378.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 31

    Molliqaj G, Schatlo B, Alaid A, et al. Accuracy of robot-guided versus freehand fluoroscopy-assisted pedicle screw insertion in thoracolumbar spinal surgery. Neurosurg Focus. 2017;42(5):E14.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32

    Ringel F, Stüer C, Reinke A, et al. Accuracy of robot-assisted placement of lumbar and sacral pedicle screws: a prospective randomized comparison to conventional freehand screw implantation. Spine (Phila Pa 1976). 2012;37(8):E496E501.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33

    Schatlo B, Molliqaj G, Cuvinciuc V, Kotowski M, Schaller K, Tessitore E. Safety and accuracy of robot-assisted versus fluoroscopy-guided pedicle screw insertion for degenerative diseases of the lumbar spine: a matched cohort comparison. J Neurosurg Spine. 2014;20(6):636643.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34

    Yang JS, He B, Tian F, et al. Accuracy of robot-assisted percutaneous pedicle screw placement for treatment of lumbar spondylolisthesis: a comparative cohort study. Med Sci Monit. 2019;25(2479):2487.

    • Search Google Scholar
    • Export Citation

Illustration from Kong et al. (pp 4–12). Copyright Qing-Jie Kong. Used with permission.

  • View in gallery

    Operating room setup. The patient is in the lateral decubitus position. This view from the location of the navigation camera shows the reference and surveillance arrays secured to the patient’s iliac crest, the C-arm with the calibration plate in front of the patient, the robot behind the patient, and the C-arm screen at the head of the table. Figure is available in color online only.

  • View in gallery

    Placement of the reference and surveillance arrays to the patient’s up-side iliac crest. Figure is available in color online only.

  • 1

    Foley KT, Holly LT, Schwender JD. Minimally invasive lumbar fusion. Spine (Phila Pa 1976). 2003;28(15)(suppl):S26S35.

  • 2

    Holly LT, Schwender JD, Rouben DP, Foley KT. Minimally invasive transforaminal lumbar interbody fusion: indications, technique, and complications. Neurosurg Focus. 2006;20(3):E6.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Isaacs RE, Podichetty VK, Santiago P, et al. Minimally invasive microendoscopy-assisted transforaminal lumbar interbody fusion with instrumentation. J Neurosurg Spine. 2005;3(2):98105.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Spitz SM, Sandhu FA, Voyadzis JM. Percutaneous "K-wireless" pedicle screw fixation technique: an evaluation of the initial experience of 100 screws with assessment of accuracy, radiation exposure, and procedure time. J Neurosurg Spine. 2015;22(4):422431.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Kim DY, Lee SH, Chung SK, Lee HY. Comparison of multifidus muscle atrophy and trunk extension muscle strength: percutaneous versus open pedicle screw fixation. Spine (Phila Pa 1976). 2005;30(1):123129.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 6

    Park Y, Ha JW. Comparison of one-level posterior lumbar interbody fusion performed with a minimally invasive approach or a traditional open approach. Spine (Phila Pa 1976). 2007;32(5):537543.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 7

    Stevens KJ, Spenciner DB, Griffiths KL, et al. Comparison of minimally invasive and conventional open posterolateral lumbar fusion using magnetic resonance imaging and retraction pressure studies. J Spinal Disord Tech. 2006;19(2):7786.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Voyadzis JM, Anaizi AN. Minimally invasive lumbar transfacet screw fixation in the lateral decubitus position after extreme lateral interbody fusion: a technique and feasibility study. J Spinal Disord Tech. 2013;26(2):98106.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Huntsman KT, Riggleman JR, Ahrendtsen LA, Ledonio CG. Navigated robot-guided pedicle screws placed successfully in single-position lateral lumbar interbody fusion. J Robot Surg. 2020;14(4):643647.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Ziino C, Konopka JA, Ajiboye RM, Ledesma JB, Koltsov JCB, Cheng I. Single position versus lateral-then-prone positioning for lateral interbody fusion and pedicle screw fixation. J Spine Surg. 2018;4(4):717724.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Ouchida J, Kanemura T, Satake K, Nakashima H, Ishikawa Y, Imagama S. Simultaneous single-position lateral interbody fusion and percutaneous pedicle screw fixation using O-arm-based navigation reduces the occupancy time of the operating room. Eur Spine J. 2020;29(6):12771286.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Blizzard DJ, Thomas JA. MIS single-position lateral and oblique lateral lumbar interbody fusion and bilateral pedicle screw fixation: feasibility and perioperative results. Spine (Phila Pa 1976). 2018;43(6):440446.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13

    Hiyama A, Sakai D, Sato M, Watanabe M. The analysis of percutaneous pedicle screw technique with guide wire-less in lateral decubitus position following extreme lateral interbody fusion. J Orthop Surg Res. 2019;14(1):304.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Fayed I, Tai A, Triano M, et al. Robot-assisted percutaneous pedicle screw placement: evaluation of accuracy of the first 100 screws and comparison with cohort of fluoroscopy-guided screws. World Neurosurg. 2020;143:e492e502.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Godzik J, Walker CT, Hartman C, et al. A quantitative assessment of the accuracy and reliability of robotically guided percutaneous pedicle screw placement: technique and application accuracy. Oper Neurosurg (Hagerstown). 2019;17(4):389395.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 16

    Overley SC, Cho SK, Mehta AI, Arnold PM. Navigation and robotics in spinal surgery: where are we now?. Neurosurgery. 2017;80(3S):S86S99.

  • 17

    Jain D, Manning J, Lord E, et al. Initial single-institution experience with a novel robotic-navigation system for thoracolumbar pedicle screw and pelvic screw placement with 643 screws. Int J Spine Surg. 2019;13(5):459463.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Hiyama A, Katoh H, Sakai D, Sato M, Tanaka M, Watanabe M. Accuracy of percutaneous pedicle screw placement after single-position versus dual-position insertion for lateral interbody fusion and pedicle screw fixation using fluoroscopy. Asian Spine J. Published online May 4, 2021. doi: 10.31616/asj.2020.0526

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Hiyama A, Katoh H, Sakai D, Sato M, Tanaka M, Watanabe M. Comparison of radiological changes after single-position versus dual- position for lateral interbody fusion and pedicle screw fixation. BMC Musculoskelet Disord. 2019;20(1):601.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Drazin D, Kim TT, Johnson JP. Simultaneous lateral interbody fusion and posterior percutaneous instrumentation: early experience and technical considerations. BioMed Res Int. 2015;2015:458284.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Buckland AJ, Ashayeri K, Leon C, et al. Single position circumferential fusion improves operative efficiency, reduces complications and length of stay compared with traditional circumferential fusion. Spine J. 2021;21(5):810820.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Lamartina C, Berjano P. Prone single-position extreme lateral interbody fusion (Pro-XLIF): preliminary results. Eur Spine J. 2020;29(suppl 1):613.

  • 23

    Martirosyan NL, Uribe JS, Randolph BM, Buchanan RI. Prone lateral lumbar interbody fusion: case report and technical note. World Neurosurg. 2020;144:170177.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Walker CT, Farber SH, Gandhi S, Godzik J, Turner JD, Uribe JS. Single-position prone lateral interbody fusion improves segmental lordosis in lumbar spondylolisthesis. World Neurosurg. 2021;151:e786e792.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Pimenta L, Taylor WR, Stone LE, Wali AR, Santiago-Dieppa DR. Prone transpsoas technique for simultaneous single-position access to the anterior and posterior lumbar spine. Oper Neurosurg (Hagerstown). 2020;20(1):E5E12.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 26

    Pimenta L, Amaral R, Taylor W, et al. The prone transpsoas technique: preliminary radiographic results of a multicenter experience. Eur Spine J. 2021;30(1):108113.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27

    Godzik J, Ohiorhenuan IE, Xu DS, et al. Single-position prone lateral approach: cadaveric feasibility study and early clinical experience. Neurosurg Focus. 2020;49(3):E15.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Staartjes VE, Klukowska AM, Schröder ML. Pedicle screw revision in robot-guided, navigated, and freehand thoracolumbar instrumentation: a systematic review and meta-analysis. World Neurosurg. 2018;116:433443.e8.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Kantelhardt SR, Martinez R, Baerwinkel S, Burger R, Giese A, Rohde V. Perioperative course and accuracy of screw positioning in conventional, open robotic-guided and percutaneous robotic-guided, pedicle screw placement. Eur Spine J. 2011;20:860868.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 30

    Laudato PA, Pierzchala K, Schizas C. Pedicle screw insertion accuracy using O-Arm, robotic guidance, or freehand technique: a comparative Study. Spine (Phila Pa 1976). 2018;43(6):E373E378.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 31

    Molliqaj G, Schatlo B, Alaid A, et al. Accuracy of robot-guided versus freehand fluoroscopy-assisted pedicle screw insertion in thoracolumbar spinal surgery. Neurosurg Focus. 2017;42(5):E14.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32

    Ringel F, Stüer C, Reinke A, et al. Accuracy of robot-assisted placement of lumbar and sacral pedicle screws: a prospective randomized comparison to conventional freehand screw implantation. Spine (Phila Pa 1976). 2012;37(8):E496E501.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 33

    Schatlo B, Molliqaj G, Cuvinciuc V, Kotowski M, Schaller K, Tessitore E. Safety and accuracy of robot-assisted versus fluoroscopy-guided pedicle screw insertion for degenerative diseases of the lumbar spine: a matched cohort comparison. J Neurosurg Spine. 2014;20(6):636643.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34

    Yang JS, He B, Tian F, et al. Accuracy of robot-assisted percutaneous pedicle screw placement for treatment of lumbar spondylolisthesis: a comparative cohort study. Med Sci Monit. 2019;25(2479):2487.

    • Search Google Scholar
    • Export Citation

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