Nerve injury in the arm and hand : epidemiology, rehabilitation interventions and clinical outcome

<p dir="ltr">Peripheral nerve injuries affecting the arm and hand can lead to significant functional impairments, limiting the performance of daily activities and negatively impacting quality of life. Due to the intricate anatomy of essential motor and sensory functions in the arm and hand, nerve injuries give rise to complex clinical challenges. Despite advances in surgical techniques and rehabilitation interventions, results are often suboptimal and differ substantially. This thesis comprises five studies. The overall aim was to investigate incidence and outcomes, evaluate current rehabilitation regimens and refine rehabilitation strategies after peripheral nerve injuries in the arm and hand, in order to enhance functional recovery. Through outcome evaluation, qualitative studies and in-depth understanding of participants' experiences, along with the exploration of innovative rehabilitation approaches, this thesis seeks to contribute to the development of more effective, evidence-based rehabilitation protocols tailored to the unique individual.</p><p dir="ltr">Paper I investigated the epidemiology, demographics and postoperative care in 1004 patients treated surgically for a digital nerve injury between 2012 and 2018, identified through the Swedish Hand Surgery registry (HAKIR). The study showed no change in incidence of digital nerve injuries during the study period. Considerable variation in utilization of healthcare resources was evident. Few participants underwent postoperative sensory assessments, and only two-thirds received rehabilitation targeting nerve specific interventions. The findings highlight the need for standardized postoperative care, including rehabilitation and assessment protocols after digital nerve injury.</p><p dir="ltr">Paper II investigated subjective and objective outcomes in 86 (matched-pairs) patients who underwent surgical repair of an isolated digital nerve injury. Two groups were formed, based on the affected digit: those with injuries to the thumb or little finger (border digit group), and those with injuries to the index, middle, or ring finger (middle finger group). Participants were assessed 3-10 years post-repair. Hand function indicated no significant difference between injury to border digits or central fingers; however, grip strength was significantly lower following central finger injuries. Tactile discrimination and touch perception yielded best outcomes in participants under 44 years of age. Neuropathic pain was identified in a large proportion of participants; 19 (44%) in the border digit injury group and 24 (56%) in the central fingers injury group. Participants reported a low level of disability in the upper extremity as evaluated by the Quick Disabilities of the Arm, Shoulder and Hand score. Numbness and cold sensitivity were the symptoms graded as worst after digital nerve injury. Rather than indicating outcome differences based on injury location, this study suggests that similar rehabilitation approaches are appropriate regardless of which specific finger that is injured. A particular focus on sensory rehabilitation targeting cold intolerance and pain treatment is important.</p><p dir="ltr">Paper III explores and describes the experience of rehabilitation after a traumatic brachial plexus injury (TBPI). Transcripts from five focus group discussions with 21 participants treated for a TBPI were coded and analysed with a qualitative content analysis. The discussion guide contained questions regarding the experience of rehabilitation. The results indicate a wide gap in access to health care with an overarching theme, "a fight on their own" to receive a tailored rehabilitation approach. Three themes emerged 1) Lack of tailored rehabilitation in a life-changing situation, 2) Crucial prerequisites for engagement in rehabilitation, and 3) Life will never be the same. This study highlights the importance of competent and committed rehabilitation staff in ensuring active patient engagement and the successful implementation of holistic, person-centred rehabilitation across all stages of care. The participants lacked access to peer interaction, up-to-date technology and rehabilitation that emphasized activity and participation. Participants experienced rehabilitation after TBPI to primarily focus on joint movement and hand exercises, emphasizing motor function recovery through repetitive movements and home training. In addition, they experienced that the impact extended beyond the arm to affect one's entire life and mental state. As a result, rehabilitation was considered most effective when provided by an interdisciplinary team with a person-centred approach.</p><p dir="ltr">Paper IV explored patients' physical activity level before and after a nerve injury in the arm and hand. A qualitative interview study with 20 participants, 1-3 years after a nerve injury was conducted with content analysis. Results indicate that physical activity was altered and generally decreased after a nerve injury in the arm and hand. This was evident regardless of the location and severity of the nerve injury. The greatest barriers for being physically active were identified among patients with no prior exercise habits or insufficient support from healthcare providers. The period immediately after surgery was the most inactive period. Greater difficulties in resuming previous activities were observed among those for whom the injury had been a dramatic experience. Previously inactive individuals often faced barriers too significant to overcome independently, highlighting the need for targeted support to facilitate physical activity following upper extremity nerve injuries.</p><p dir="ltr">Paper V is a pilot study exploring the feasibility of an aerobic exercise program, performed on a stationary bike, after peripheral nerve injuries in the arm and hand. The primary outcome of the study was to assess the acceptability of the intervention. Secondary outcome measures explored study recruitment rate, feasibility in pre- and post-intervention testing, and acceptability of assessing the outcome measures related to sensation, pain and hand function. Further, the study explored serum levels of Brain Derived Neurotrophic Factor, BDNF and oxygen uptake capacity, VO2max. The study also explored pain and sensory functions. The cycling intervention proved to be safe and feasible, but the intervention required adjustments and pain monitoring. Patient reported outcomes evaluating disability and hand function improved over the study period. BDNF levels were detectable and increased from baseline to the end of the intervention, remaining elevated six weeks after the intervention ended. We conclude that intervention and outcome measurements must be tailored to injury level. Further studies are needed to explore the effects of physical activity and BDNF levels on sensory and motor function, as well as on pain.</p><h3>List of scientific papers</h3><p dir="ltr">I. Incidence, demographics and rehabilitation after digital nerve injury: A population-based study of 1004 adult patients in Sweden. <b>Linda Evertsson</b>, Carin Carlsson, Christina Turesson, Melih Selcuk Ezer, Marianne Arner, Cecilia Mellstrand Navarro. PLoS One. 2023 Apr 7;18(4):e0283907. <a href="https://doi.org/10.1371/journal.pone.0283907" rel="noreferrer" target="_blank">https://doi.org/10.1371/journal.pone.0283907</a></p><p dir="ltr">II. Long-term subjective and objective outcomes after digital nerve repair: a cohort study. <b>Linda Evertsson</b>, Anders Björkman, Christina Turesson, Marianne Arner, Cecilia Mellstrand Navarro. J Hand Surg Eur. 2025 May;50(5):649-658. <a href="https://doi.org/10.1177/17531934241286116" rel="noreferrer" target="_blank">https://doi.org/10.1177/17531934241286116</a></p><p dir="ltr">III. A fight on your own - experiences of rehabilitation after traumatic brachial plexus injuries. <b>Linda Evertsson</b>, Helena Millkvist, Stina Sjerén, Lena Rosenberg, Ingeborg Nilsson. Disabil Rehabil. 2025 Aug;47(17):4506-4514. <a href="https://doi.org/10.1080/09638288.2025.2452371" rel="noreferrer" target="_blank">https://doi.org/10.1080/09638288.2025.2452371</a></p><p dir="ltr">IV. Navigate physical activity after a nerve injury in the arm and hand. [Manuscript]</p><p dir="ltr">V. Pilot/feasibility study using physical activity as intervention after a nerve injury in the arm and hand. [Manuscript]</p>