Rhabdomyolysis after spinal fusion surgery: management schema and prevention of a catastrophic complication

PURPOSE

Rhabdomyolysis is a clinical syndrome with the potential to cause cardiac arrhythmias, renal failure, and even death. Currently, there are no studies regarding risk factors for developing post-operative rhabdomyolysis (POR) after spinal fusion surgeries. Our objective was to study risk factors associated with, and to develop a decision-making framework for post-operative rhabdomyolysis after spinal fusion surgery.

METHODS

We performed a retrospective cohort study of all spinal fusions of three or more levels over 2.25 years by a single surgeon at two centers. POR was defined as a creatine phosphokinase (CPK) greater than 2000 IU/L.

RESULTS

76 surgical procedures on 72 patients were identified. Rate of POR in our cohort was 22% (17/76). Male sex was associated with POR (p < 0.05). Previously validated risk factors: younger age, lower ASA score, elevated BMI, higher pre-operative creatinine, increased intraoperative blood loss, specific surgical positions, and length of surgery, were not associated with POR. In a logistic regression model, male gender increases the odds of POR in all patients 5.82-fold (p = 0.047). In patients without a second surgery within seven days, a logistic regression model suggests each additional level fused via transpsoas approach, and male gender, increases the risk of POR 1.81-times (p = 0.015), and 6.26-times (p = 0.047), respectively. In patients with posterior fusions, a logistic regression model suggests increasing the number of lateral levels fused via transpsoas approach in the same surgery, and male gender, increases the risk of POR 1.68-times and 6.34-times, respectively. In these same subgroups, increased thickness of the psoas major in lateral transpsoas fusions increased risk of POR (p = 0.023, p = 0.046, respectively).

CONCLUSIONS

In spinal fusions, increasing the number of lateral levels fused via transpsoas approach, and male gender, predispose patients to increased risk of POR in those without a second surgery within seven days, and in those with a simultaneous posterior fusion.

Comparison of Nonneurological Structures at Risk During Anterior-to-Psoas Versus Transpsoas Surgical Approaches Using Abdominal CT Imaging From L1 to S1

BACKGROUND

The kidneys, ribs, liver, spleen, and iliac crests can pose access-related issues to the disc space during both anterior-to-psoas (ATP) and transpsoas (TP) surgical approaches. The aim of this study was to identify and compare the presence and degree of obstruction caused by these structures for the ATP and TP approaches bilaterally from L1 to S1 using abdominal computed tomography.

METHODS

Presence of obstruction by a given structure was recorded if the structure was within ATP or TP borders. Degree of obstruction was calculated as the quotient of the structure measurement within the ATP or TP approach divided by the entire corridor length at the point of obstruction.

RESULTS

The percentage of time the left kidney was present during the ATP vs TP approaches at L1 to L2 was 44% vs 89% (P < 0.001), at L2 to L3 was 26% vs 75% (P < 0.001), and at L3 to L4 was 5% vs 19% (P < 0.001). For the right kidney, these values were 37% vs 78% (P < 0.001), 43% vs 71% (P < 0.001), and 11% vs 18% (P < 0.001). The percentage of time the left rib was present during ATP vs TP approaches was 41% vs 81% (P < 0.001) at L1 to L2 and 11% vs 26% (P = 0.413) at L2 to L3. With respect to the liver, the ATP approach was obstructed 56%, 30%, and 9% of the time at the levels of L1 to L2, L2 to L3, and L3 to L4; the liver was not present in L1 to L4 TP approach.

CONCLUSIONS

This study is the first to both characterize and compare nonneurological structures at risk during ATP and TP fusion approaches bilaterally from L1 to S1 using abdominal computed tomography. Findings suggest the ATP approach poses less structures at risk relative to the TP approach with respect to the kidneys, ribs, and iliac crests bilaterally. The TP approach offers advantages compared with ATP approach with respect to the liver and spleen.

CLINICAL RELEVANCE

Findings from this study are clinically relevant for ATP and TP surgical approach planning.

LEVEL OF EVIDENCE: 3

Lateral lumbar interbody fusion - clinical outcomes, fusion rates and complications with recombinant human bone morphogenetic protein-2

BACKGROUND

The authors report an Australian experience of lateral lumbar interbody fusion (LLIF) with respect to clinical outcomes, fusion rates, and complications, with recombinant human bone morphogenetic protein-2 (rhBMP-2) and other graft materials.

METHODS

Retrospective cohort study of LLIF patients 2011-2021. LLIFs performed lateral decubitus by four experienced surgeons past their learning curve. Graft materials classified rhBMP-2 or non-rhBMP-2. Patient-reported outcomes assessed by VAS, ODI, and SF-12 preoperatively and postoperatively. Fusion rates assessed by CT postoperatively at 6 and 12 months. Complications classified minor or major. Clinical outcomes and complications analysed and compared between rhBMP-2 and non-rhBMP-2 groups.

RESULTS

A cohort of 343 patients underwent 437 levels of LLIF. Mean age 67 ± 11 years (range 29-89) with a female preponderance (65%). Mean BMI 29kg/m2 (18-56). Most common operated levels L3/4 (36%) and L4/5 (35%). VAS, ODI and SF-12 improved significantly from baseline. Total complication rate 15% (53/343) with minor 11% (39/343) and major 4% (14/343). Ten patients returned to OR (2-wound infection, 8-further instrumentation and decompression). Most patients (264, 77%) received rhBMP-2, the remainder a non-rhBMP-2 graft material. No significant differences between groups at baseline. No increase in minor or major complications in the rhBMP-2 group compared to the non-rhBMP-2 group respectively; (10.6% vs 13.9% [p = 0.42], 2.7% vs 8.9% [p < 0.01]). Fusion rates significantly higher in the rhBMP-2 group at 6 and 12 months (63% vs 40%, [p < 0.01], 92% vs 80%, [p < 0.02]).

CONCLUSION

LLIF is a safe and efficacious procedure. rhBMP-2 in LLIF produced earlier and higher fusion rates compared to available non-rhBMP-2 graft substitutes.

Changes in Segmental and Lumbar Lordosis After Lateral Lumbar Interbody Fusion With Different Lordotic Cage Angulations

BACKGROUND

Lateral lumbar interbody fusion (LLIF) affords a wide operative corridor to allow for a large interbody cage implantation for segmental reconstruction. There is a paucity of data describing segmental lordosis (SL) achieved with lordotic implants of varying angles. Here we compare changes in SL and lumbar lordosis (LL) after implantation of 6°, 10°, and 12° cages.

METHODS

We retrospectively reviewed LLIF cases over a 5.5-year period. We derived SL and LL using the standard cobb angle measurement from a standing lateral radiograph. We analyzed mean changes in SL and LL over time using the linear mixed effect model to estimate these longitudinal changes.

RESULTS

The most frequently treated level was L3-4, followed by L4-5. Significant increases in mean SL were found at each follow-up time point for all the cohorts. In an intercohort comparison, the mean changes in SL at immediate postoperative and last follow-up were significantly greater in the 10° cohort than 6° ([7.4° versus 3.1°, P = .004], [6.1° versus 2.3°, P = .025] respectively). The 12° cohort had higher mean change in SL at last follow-up than the 6° cohort (5.9° versus 2.3°, P = .022). There was no difference in mean change in SL between the 10° and 12° cohorts. No difference in overall mean LL over time was found. In terms of mean change in LL, no difference was observed except at immediate and 6-month postoperative in the 10° cohort ([9.6°, P = .001], [8.5, P = .003] respectively). By comparing mean change in LL, no difference existed except between the 10° and 6° immediately after surgery (9.6° versus 0.2°, P = .006).

CONCLUSIONS

LLIF cages significantly improve SL at the index level. However, this increase in SL is greater for 10° and 12° cages than the standard 6° cage. Use of 10° cages also resulted in overall improved LL than 6° cages.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Lateral lumbar interbody fusion.

The impact of adding posterior instrumentation to transpsoas lateral fusion: a systematic review and meta-analysis

OBJECTIVETranspsoas lateral interbody fusion is one of the lateral minimally invasive approaches for lumbar spine surgery. Most surgeons insert the interbody cage laterally and then insert pedicle or cortical screw and rod instrumentation posteriorly. However, standalone cages have also been used to avoid posterior instrumentation. To the best of the authors' knowledge, the literature on comparison of the two approaches is sparse.METHODSThe authors performed a systematic review and meta-analysis of the available literature on transpsoas lateral interbody fusion by an electronic search of the PubMed, EMBASE, and Scopus databases using PRISMA guidelines. They compared patients undergoing transpsoas standalone fusion (TP) with those undergoing transpsoas fusion with posterior instrumentation (TPP).RESULTSA total of 28 studies with 1462 patients were included. Three hundred and seventy-four patients underwent TPP, and 956 patients underwent TP. The mean patient age ranged from 45.7 to 68 years in the TP group, and 50 to 67.7 years in the TPP group. The incidence of reoperation was found to be higher for TP (0.08, 95% confidence interval [CI] 0.04-0.11) compared to TPP (0.03, 95% CI 0.01-0.06; p = 0.057). Similarly, the incidence of cage movement was found to be greater in TP (0.18, 95% CI 0.10-0.26) compared to TPP (0.03, 95% CI 0.00-0.05; p < 0.001). Oswestry Disability Index (ODI) and visual analog scale (VAS) scores and postoperative transient deficits were found to be comparable between the two groups.CONCLUSIONSThese results appear to suggest that addition of posterior instrumentation to transpsoas fusion is associated with decreased reoperations and cage movements. The results of previous systematic reviews and meta-analyses should be reevaluated in light of these results, which seem to suggest that higher reoperation and subsidence rates may be due to the use of the standalone technique.

Short-term outcomes of lateral lumbar interbody fusion without decompression for the treatment of symptomatic degenerative spondylolisthesis at L4-5

OBJECTIVE Recently, authors have called into question the utility and complication index of the lateral lumbar interbody fusion procedure at the L4-5 level. Furthermore, the need for direct decompression has also been debated. Here, the authors report the clinical and radiographic outcomes of transpsoas lumbar interbody fusion, relying only on indirect decompression to treat patients with neurogenic claudication secondary to Grade 1 and 2 spondylolisthesis at the L4-5 level. METHODS The authors conducted a retrospective evaluation of 18 consecutive patients with Grade 1 or 2 spondylolisthesis from a prospectively maintained database. All patients underwent a transpsoas approach, followed by posterior percutaneous instrumentation without decompression. The Oswestry Disability Index (ODI) and SF-12 were administered during the clinical evaluations. Radiographic evaluation was also performed. The mean follow-up was 6.2 months. RESULTS Fifteen patients with Grade 1 and 3 patients with Grade 2 spondylolisthesis were identified and underwent fusion at a total of 20 levels. The mean operative time was 165 minutes for the combined anterior and posterior phases of the operation. The estimated blood loss was 113 ml. The most common cage width in the anteroposterior dimension was 22 mm (78%). Anterior thigh dysesthesia was identified on detailed sensory evaluation in 6 of 18 patients (33%); all patients experienced resolution within 6 months postoperatively. No patient had lasting sensory loss or motor deficit. The average ODI score improved 26 points by the 6-month follow-up. At the 6-month follow-up, the SF-12 mean Physical and Mental Component Summary scores improved by 11.9% and 9.6%, respectively. No patient required additional decompression postoperatively. CONCLUSIONS This study offers clinical results to establish lateral lumbar interbody fusion as an effective technique for the treatment of Grade 1 or 2 degenerative spondylolisthesis at L4-5. The use of this surgical approach provides a minimally invasive solution that offers excellent arthrodesis rates as well as favorable clinical and radiological outcomes, with low rates of postoperative complications. However, adhering to the techniques of transpsoas lateral surgery, such as minimal table break, an initial look-and-see approach to the psoas, clear identification of the plexus, minimal cranial caudal expansion of the retractor, mobilization of any traversing sensory nerves, and total psoas dilation times less than 20 minutes, ensures the lowest possible complication profile for both visceral and neural injuries even in the narrow safe zones when accessing the L4-5 disc space in patients with degenerative spondylolisthesis.

Complications for minimally invasive lateral interbody arthrodesis: a systematic review and meta-analysis comparing prepsoas and transpsoas approaches

OBJECTIVEMinimally invasive anterolateral retroperitoneal approaches for lumbar interbody arthrodesis have distinct advantages attractive to spine surgeons. Prepsoas or transpsoas trajectories can be employed with differing complication profiles because of the inherent anatomical differences encountered in each approach. The evidence comparing them remains limited because of poor quality data. Here, the authors sought to systematically review the available literature and perform a meta-analysis comparing the two techniques.METHODSA systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A database search was used to identify eligible studies. Prepsoas and transpsoas studies were compiled, and each study was assessed for inclusion criteria. Complication rates were recorded and compared between approach groups. Studies incorporating an analysis of postoperative subsidence and pseudarthrosis rates were also assessed and compared.RESULTSFor the prepsoas studies, 20 studies for the complications analysis and 8 studies for the pseudarthrosis outcomes analysis were included. For the transpsoas studies, 39 studies for the complications analysis and 19 studies for the pseudarthrosis outcomes analysis were included. For the complications analysis, 1874 patients treated via the prepsoas approach and 4607 treated with the transpsoas approach were included. In the transpsoas group, there was a higher rate of transient sensory symptoms (21.7% vs 8.7%, p = 0.002), transient hip flexor weakness (19.7% vs 5.7%, p < 0.001), and permanent neurological weakness (2.8% vs 1.0%, p = 0.005). A higher rate of sympathetic nerve injury was seen in the prepsoas group (5.4% vs 0.0%, p = 0.03). Of the nonneurological complications, major vascular injury was significantly higher in the prepsoas approach (1.8% vs 0.4%, p = 0.01). There was no difference in urological or peritoneal/bowel injury, postoperative ileus, or hematomas (all p > 0.05). A higher infection rate was noted for the transpsoas group (3.1% vs 1.1%, p = 0.01). With regard to postoperative fusion outcomes, similar rates of subsidence (12.2% prepsoas vs 13.8% transpsoas, p = 0.78) and pseudarthrosis (9.9% vs 7.5%, respectively, p = 0.57) were seen between the groups at the last follow-up.CONCLUSIONSComplication rates vary for the prepsoas and transpsoas approaches owing to the variable retroperitoneal anatomy encountered during surgical dissection. While the risks of a lasting motor deficit and transient sensory disturbances are higher for the transpsoas approach, there is a reciprocal reduction in the risks of major vascular injury and sympathetic nerve injury. These results can facilitate informed decision-making and tailored surgical planning regarding the choice of minimally invasive anterolateral access to the spine.

Minimally Invasive Direct Lateral Transpsoas Approach for the Resection of a Lumbar Plexus Schwannoma: Technique Report

Objective  Traditional techniques for resection of lumbar plexus tumors have been associated with approach-related morbidity. We describe a case utilizing a minimally invasive transpsoas lateral access approach to resect a retroperitoneal tumor of the lumbar plexus.

Methods  We report a case with an extradural retroperitoneal schwannoma of the L4 nerve root that was treated with a minimally invasive direct lateral transpsoas approach using atraumatic tissue dilators and an expandable tubular retractor. The use of directional and continuous electromyographic monitoring was critical in locating the plexus and positioning the retractor immediately anterior to the tumor.

Results  The patient tolerated the procedure well without postoperative complications. The operative approach was direct and intraoperative blood loss was negligible. The patient demonstrated improved left leg strength and ambulation and resolution of paresthesias.

Conclusions  A minimally invasive direct lateral transpsoas access approach is an effective technique to safely and adequately resect extradural retroperitoneal lumbar plexus tumors.

Contralateral psoas hematoma after minimally invasive, lateral retroperitoneal transpsoas lumbar interbody fusion: a multicenter review of 3950 lumbar levels

OBJECTIVE Minimally invasive lateral lumbar interbody fusion (LLIF) via the retroperitoneal transpsoas approach is a technically demanding procedure with a multitude of potential complications. A relatively unknown complication is the contralateral psoas hematoma. The authors speculate that injury occurs from segmental vessel injury at the time of contralateral annulus release; however, this is not fully understood. In this multicenter retrospective review, the authors report the incidence of this contralateral complication and its neurological sequelae. METHODS This study was a retrospective chart review of all minimally invasive LLIF performed at participating institutions from 2008 to 2014. Exclusion criteria included an underlying diagnosis of trauma or neoplasia as well as lateral corpectomies or anterior column releases. Single-level, multilevel, and stand-alone constructs were included. All patients underwent preoperative MRI. Follow-up was at least 12 months. All complications and clinical outcomes were self-reported by each surgeon. RESULTS There were 3950 lumbar interbody cages placed via the retroperitoneal transpsoas approach, with 7 cases (0.18% incidence) of symptomatic contralateral psoas hematoma, 3 of which required reoperation for hematoma evacuation. Neurological outcome did not improve after reoperation. Reoperation occurred an average of 1 month after the initial operation due to a delay in diagnosis. In 1 case, segmental artery injury was confirmed at the time of surgery; in the others, segmental vessel injury was suspected, although it could not be confirmed. Neurological deficits persisted in 3 patients while the others remained neurologically intact. Two patients were receiving antiplatelet therapy prior to the procedure. CONCLUSIONS The contralateral psoas hematoma is a rare complication suspected to occur from segmental vessel injury during contralateral annulus release. Detailed review of preoperative imaging for aberrant vessel anatomy may prevent injury and subsequent neurological deficit.

TranS1 VEO system: a novel psoas-sparing device for transpsoas lumbar interbody fusion

Minimally invasive approaches for lumbar interbody fusion have been popularized in recent years. The retroperitoneal transpsoas approach to the lumbar spine is a technique that allows direct lateral access to the intervertebral disc space while mitigating the complications associated with traditional anterior or posterior approaches. However, a common complication of this procedure is iatrogenic injury to the psoas muscle and surrounding nerves, resulting in postsurgical motor and sensory deficits. The TranS1 VEO system (TranS1 Inc, Raleigh, NC, USA) utilizes a novel, minimally invasive transpsoas approach to the lumbar spine that allows direct visualization of the psoas and proximal nerves, potentially minimizing iatrogenic injury risk and resulting clinical morbidity. This paper describes the clinical uses, procedural details, and indications for use of the TranS1 VEO system.