Nerve Repair Strategies in Iatrogenic Inferior Alveolar Nerve Injuries: A Systematic Review

TL;DR

This systematic review evaluates surgical techniques for repairing iatrogenic inferior alveolar nerve injuries, emphasizing the importance of early intervention and technique choice for better recovery.

Contribution

The study systematically reviews evidence-based surgical repair strategies for iatrogenic IAN injuries and identifies factors influencing recovery outcomes.

Findings

Early surgical intervention within two months improves functional sensory recovery in IAN injuries.

Direct neurorrhaphy and sural nerve grafting showed the highest success rates for clean injuries.

Decompression and neurolysis were more effective in minor injuries but less so in severe or chronic cases.

Abstract

The inferior alveolar nerve (IAN) is an essential branch of the trigeminal nerve in the mandible. It provides the nerve supply to the lower lip, chin, and teeth. Despite various nerve repair strategies having been explored to enhance functional recovery, the optimal approach remains unclear. This review aims to identify evidence-based surgical repair techniques for managing iatrogenic IAN injuries. The systematic review inclusion criteria were restricted to English-language full-text articles reporting clinical outcomes of nerve repair interventions in iatrogenic IAN injury. Comprehensive literature searches were performed in PubMed, Embase, and Cochrane Library using relevant keywords and Boolean operators from 2000 to 2025. The review was conducted according to PRISMA guidelines. The methodological quality of included studies was appraised using the Joanna Briggs Institute (JBI) critical appraisal tools for randomized controlled trials (RCTs) and cohort studies.

The systematic review examined outcomes of nerve decompression, neurorrhaphy, and grafting surgeries, with populations ranging from six to 167 patients and average ages between 36 and 56 years, predominantly female. Common causes of inferior alveolar nerve (IAN) injury included third molar extractions (37.6% of cases), dental implant placement, endodontic treatments, and orthognathic surgeries, while non-surgical causes like trauma, delayed intervention, anatomical variations, and patient-related factors (e.g., age) also influenced outcomes. Surgical techniques such as decompression, neurolysis, autogenous nerve grafts (e.g., sural nerve), and neurorrhaphy were compared, with decompression and neurolysis showing 85% and 75% success rates, respectively, for minor injuries. In comparison, grafts and neurorrhaphy achieved 87.3% and 88.9% success rates for severe cases. Recovery times and outcomes were better with early intervention (<12 months), and factors like age, surgical precision, and technique (e.g., piezosurgery reducing thermal damage) significantly impacted results. Complications included donor site morbidity (e.g., temporary numbness) and incomplete recovery in delayed cases, underscoring the need for timely, skilled intervention. The review highlighted that early surgical intervention is a key determinant in achieving optimal results for IAN injury treatment. Results indicated that the selection of the surgical nerve repair strategy depends upon the patient factors, type of injury, and severity. Moreover, when surgical strategies are performed within two months of the incident, this greatly improves the chances of regaining functional sensory recovery in the affected area. The highest success rate was found with direct neurorrhaphy and sural nerve grafting among a variety of surgical techniques, most noticeable in clean injuries. The decompression and neurolysis techniques showed modest effectiveness, although they worked better in a few chronic compression cases. New approaches like using piezosurgery and computers to help with surgical navigation improve safety and lessen the injury caused by surgery. Nevertheless, nerve grafting usually leads to some short-term and easy-to-handle donor site morbidity. The lack of standardized outcome reporting and direct comparative randomized controlled trials with homogenous assessment tools limits the generalizability of the findings and recommends further validation.

Figures