Postoperative complications after surgery for lumbar spinal stenosis, assessment using two different data sources

PURPOSE

Lumbar spinal stenosis (LSS) is a prevalent disorder, and surgery for LSS is a common procedure. Postoperative complications occur after any surgery and impose costs for society and costs and additional morbidity for patients. Since complications are relatively rare, medical registries of large populations may provide valuable knowledge. However, recording of complications in registries can be incomplete. To better estimate the true prevalence of complications after LSS surgery, we reviewed two different sources of data and recorded complications for a sample of Norwegian LSS patients.

METHODS

474 patients treated surgically for LSS during 2015 and 2016 at four hospitals reported to a national spine registry (NORspine). Postoperative complications were recorded by patients in NORspine, and we cross-referenced complications documented in NORspine with the patients´ electronic patient records (EPR) to re-test the complication rates. We performed descriptive statistics of complication rates using the two different data sources above, and analyzed the association between postoperative complications and clinical outcome with logistic regression.

RESULTS

The mean (95%CI) patient age was 66.3 (65.3-67.2) years, and 254 (53.6%) were females. All patients were treated with decompression, and 51 (10.7%) received an additional fusion during the index surgery. Combining the two data sources, we found a total rate for postoperative complications of 22.4%, the NORspine registry reported a complication rate of 15.6%, and the EPR review resulted in a complication rate of 16.0%. However, the types of complications were inconsistent across the two data sources. According to NORspine, the frequency of reoperation within 90 days was 0.9% and according to EPR 3.4%. The rates of wound infection were for NORspine 3.1% and EPR review 2.1%. There was no association between postoperative complication and patient reported outcome.

CONCLUSION

Postoperative complications occurred in 22% of LSS patients. The frequency of different postoperative complications differed between the two data sources.

Long-term comparison of anterior (ALIF) versus transforaminal (TLIF) lumbar interbody fusion: a propensity score-matched register-based study

PURPOSE

Anterior (ALIF) and transforaminal (TLIF) lumbar interbody fusion have shown similar clinical outcomes at short- and medium-term follow-ups. Possible advantages of ALIF in the long run could be better disc height and lumbar lordosis and reduced risk of adjacent segment disease. We aimed to study if ALIF could be associated with superior clinical outcomes than TLIF at long-term follow-up.

METHODS

We analysed 535 patients treated with ALIF or TLIF of the L5-S1 spinal segment between 2007 and 2017 who completed long-term follow-up in a national spine registry database (NORspine). We defined treatment success after surgery as at least 30% improvement in Oswestry Disability Index (ODI) at long-term follow-up. Patients treated with ALIF and TLIF and who responded at long term were balanced by propensity score matching. The proportions of successfully treated patients within each group were compared by numbers and percentages with corresponding relative risk.

RESULTS

The mean (95%CI) age of the total study population was 50 (49-51) years, and 264 (49%) were females. The mean (95%CI) preoperative ODI score was 40 (39-42), and 174 (33%) had previous spine surgery. Propensity score matching left 120 patients in each treatment group. At a median (95%CI) of 92 (88-97) months after surgery, we found no difference in proportions successfully treated patients with ALIF versus TLIF (68 (58%) versus 77 (65%), RR (95%CI) = 0.88 (0.72 to1.08); p = 0.237).

CONCLUSIONS

This propensity score-matched national spine register study of patients treated with ALIF versus TLIF of the lumbosacral junction found no differences in proportions of successfully treated patients at long-term follow-up.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Characteristics and outcomes of patients who did not respond to a national spine surgery registry

BACKGROUND

Loss to follow-up may bias outcome assessments in medical registries. This cohort study aimed to analyze and compare patients who failed to respond with those that responded to the Norwegian Registry for Spine Surgery (NORspine).

METHODS

We analyzed a cohort of 474 consecutive patients operated for lumbar spinal stenosis at four public hospitals in Norway during a two-year period. These patients reported sociodemographic data, preoperative symptoms, and Oswestry Disability Index (ODI), numerical rating scales (NRS) for back and leg pain to NORspine at baseline and 12 months postoperatively. We contacted all patients who did not respond to NORspine after 12 months. Those who responded were termed responsive non-respondents and compared to 12 months respondents.

RESULTS

One hundred forty (30%) did not respond to NORspine 12 months after surgery and 123 were available for additional follow-up. Sixty-four of the 123 non-respondents (52%) responded to a cross-sectional survey done at a median of 50 (36-64) months after surgery. At baseline, non-respondents were younger 63 (SD 11.7) vs. 68 (SD 9.9) years (mean difference (95% CI) 4.7 years (2.6 to 6.7); p =  < 0.001) and more frequently smokers 41 (30%) vs. 70 (21%) RR (95%CI) = 1.40 (1.01 to 1.95); p = 0.044. There were no other relevant differences in other sociodemographic variables or preoperative symptoms. We found no differences in the effect of surgery on non-respondents vs. respondents (ODI (SD) = 28.2 (19.9) vs. 25.2 (18.9), MD (95%CI) = 3.0 ( -2.1 to 8.1); p = 0.250).

CONCLUSION

We found that 30% of patients did not respond to NORspine at 12 months after spine surgery. Non-respondents were somewhat younger and smoked more frequently than respondents; however, there were no differences in patient-reported outcome measures. Our findings suggest that attrition bias in NORspine was random and due to non-modifiable factors.

Incidental dural tears associated with worse clinical outcomes in patients operated for lumbar spinal stenosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Incidental dural (ID) tear is a common complication of spine surgery with a prevalence of 4-10%. The association between ID and clinical outcome is uncertain. Former studies found only minor differences in Oswestry Disability Index (ODI). We aimed to examine the association of ID with treatment failure after surgery for lumbar spinal stenosis (LSS).

METHODS

Between 2007 and 2017, 11,873 LSS patients reported to the national Norwegian spine registry (NORspine), and 8,919 (75.1%) completed the 12-month follow-up. We used multivariate logistic regression to study the association between ID and failure after surgery, defined as no effect or any degrees of worsening; we also compared mean ODI between those who suffered a perioperative ID and those who did not.

RESULTS

The mean (95% CI) age was 66.6 (66.4-66.9) years, and 52% were females. The mean (95% CI) preoperative ODI score (95% CI) was 39.8 (39.4-40.1); all patients were operated on with decompression, and 1125 (12.6%) had an additional fusion procedure. The prevalence of ID was 4.9% (439/8919), and the prevalence of failure was 20.6% (1829/8919). Unadjusted odds ratio (OR) (95% CI) for failure for ID was 1.51 (1.22-1.88); p < 0.001, adjusted OR (95% CI) was 1.44 (1.11-1.86); p = 0.002. Mean postoperative ODI 12 months after surgery was 27.9 for ID vs. 23.6 for no ID.

CONCLUSION

We demonstrated a significant association between ID and increased odds for patient-reported failure 12 months after surgery. However, the magnitude of the detrimental effect of ID on the clinical outcome was small.

Criteria for failure and worsening after surgery for lumbar spinal stenosis: a prospective national spine registry observational study

BACKGROUND CONTEXT

Criteria for success after surgical treatment of lumbar spinal stenosis (LSS) have been defined previously; however, there are no clear criteria for failure and worsening after surgery as assessed by patient-reported outcome measures (PROMs).

PURPOSE

We aimed to quantify changes in standard PROMs that most accurately identified failure and worsening after surgery for LSS.

STUDY DESIGN /SETTING

Retrospective analysis of prospective national spine registry data with 12-months follow-up.

PATIENT SAMPLE

We analyzed 10,822 patients aged 50 years and older operated in Norway during a decade, and 8,258 (76%) responded 12 months after surgery.

OUTCOME MEASURES (PROMS)

We calculated final scores, absolute changes, and percentage changes for Oswestry Disability Index (ODI), Numeric Rating Scale (NRS) for back and leg pain (0-10), and EuroQol-5D (EQ-5D). These 12 PROM derivates were compared to the Global Perceived Effect (GPE), a 7-point Likert scale.

METHODS

We used ODI, NRS back and leg pain, and EQ-5D 12 months after surgery to identify patients with failure (no effect) and worsening (clinical deterioration). The corresponding GPE at 12-months was graded as failure (GPE=4-7) and worsening (GPE=6-7) and used as an external criterion. To quantify the most accurate cut-off values corresponding to failure and worsening, we calculated areas under the curves (AUCs) of receiver operating characteristics (ROC) curves for the respective PROM derivates.

RESULTS

Mean (95% CI) age was 68.3 (68.1 - 68.5) years, and 52% were females. There were 1,683 (20%) failures, and 476 (6%) patients were worse after surgery. The mean (95% CI) pre- and postoperative ODIs were 39.8 (39.5 - 40.2) and 23.7 (23.3 - 24.1), respectively. At 12 months, the mean difference (95% CI) in ODI was 16.1 (15.7 - 16.4), and the mean (95% CI) percentage improvement 38.8% (37.8 - 38.8). The PROM derivates identified failure and worsening accurately (AUC>0.80), except for the absolute change in EQ-5D. The ODI derivates were most accurate to identify both failure and worsening. We found that less than 20% improvement in ODI most accurately identified failure (AUC=0.89 [95% CI: 0.88 to 0.90]), and an ODI final score of 39 points or more most accurately identified worsening (AUC =0.91 [95% CI: 0.90 - 0.92]).

CONCLUSIONS

In this national register study, ODI derivates were most accurate to identify both failure and worsening after surgery for degenerative lumbar spinal stenosis. We recommend use of ODI percentage change and ODI final score for further studies of failure and worsening in elective spine surgery.

Flexor hallucis longus tendon transfer for chronic Achilles tendon rupture. A retrospective study

BACKGROUND

The transfer of Flexor Hallucis Longus Tendon (FHL) is an established method for the treatment of chronic Achilles tendon ruptures. An extensive examination of power, strength, endurance and complications related to this procedure is presented.

METHODS

21 patients treated with open FHL transfer for chronic Achilles tendon rupture were studied retrospectively. Medical records were reviewed. The patients were examined with a test battery for triceps surae strength, functional tests and PROMs.

RESULTS

The median maximal concentric strength was equal,1300 vs 1336W, comparing affected with unaffected side. The endurance tests showed a larger difference, 219J vs. 2398J, respectively. The median AOFAS score was 87. 11 of 21 patients sustained one or more complications; the most common were infection, disturbed wound healing, and clawing of small toes.

CONCLUSIONS

Patients achieve almost normal maximal strength after open FHL transfer, but endurance is notably lower. The complication rate was high.