*4.5. Strengths, Limitations and Future Directions*

The strength of this study is the inclusion of a real-world TBI population from a defined geographical region with little migration and no exclusion criteria based on age or preinjury comorbidities. The study provides a useful overview and captures trends regarding patient flow into the direct pathway to specialized rehabilitation from a Level 1 trauma center. However, there are limitations to consider. There was no information available in the Oslo TBI Registry—Neurosurgery on later access to rehabilitation for patients not included in the direct pathway. In addition, there was a lack of information on longer-term outcomes for both groups. Thus, we cannot draw firm conclusions on the impact of direct or indirect care pathways in this study. Furthermore, the variables are crude and based on acute clinical parameters; they do not explain the multifaceted reality at the individual level. Information in the database is derived from medical records, where it is well known that information quality is variable. Moreover, database coding

errors cannot be completely ruled out, although the database is continuously searched and adjusted for coding errors.

Our results highlight the importance of continued focus on optimizing and maintaining a direct TBI care pathway and systematic assessment of rehabilitation needs during the acute phase for all hospital-admitted patients with TBI. To do so, it would be beneficial to develop recommendations for clinical practice to assess rehabilitation needs before patients are discharged from acute care. Finally, future studies on TBI care pathways should focus on patients >64 years.

**Author Contributions:** Conceptualization, C.T., N.A., M.A. and E.H.; methodology, C.T., N.A., M.A. and E.H.; software, C.T.; validation, C.B.; formal analysis, C.T. and C.B.; investigation, C.T. and E.H.; resources, Oslo University Hospital; data curation, C.T. and E.H.; writing—original draft preparation, C.T., N.A., E.H. and M.A.; writing—review and editing, C.B., P.R., T.H. and C.R.; visualization, C.T.; supervision, N.A., E.H. and M.A.; project administration, M.A. and E.H.; funding acquisition, E.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** The Oslo TBI registry uses the Medinsight database and is approved by the Oslo University Hospital data protection officer (DPO) with approval number 2016/17569, and this study is approved by OUH DPO approval number 18/20658. Ethical review and approval were waived for this study because the study qualifies as a quality control study.

**Informed Consent Statement:** Patient consent was waived because anonymized data were retrieved from the Oslo TBI Registry—Neurosurgery.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author if considered appropriate. The data are not publicly available due to privacy and ethical restrictions.

**Acknowledgments:** Ola Fougner Skaansar, for substantial contribution in collecting data.

**Conflicts of Interest:** The authors declare no conflict of interest.
