# Inclence of Chronic Pain following Oral Soft Tissue Biopsies: A Retrospective Study
## 2 Materials and Methods  
A retrospective study examined all the medical records of patients undergoing soft-tissue Oral Biopsy (STOB) in the Department of Oral and Maxillofacial Surgery at Hadassah Medical center, Jerusalem Israel between the years 2003 to 2022.  
The institutional review board approved the study (#0329-21-HMO).  
Records of patients with a history of chronic pain at the biopsy site (before the procedure), and of individuals younger than 18 were excluded (2).  
Primary and resultant data were recorded on an intake form. Demographic data included gender and age. Lesion location was recorded as buccal mucosa, gingiva, tongue, lips, hard/soft palate, floor of the mouth, retromolar pad and vestibule area (Table 1). Histopathological diagnosis was recorded and included 64 malignant and nonmalignant lesions (Supplementary Materials, Table S1); these were divided to 8 general groups (Figure 1). The patients with malignant lesions underwent extensive surgery within 3 months of the biopsy and were therefore excluded from our statistical analysis of chronic pain.  
Descriptive clinical pre-biopsy features included exophytic, endophytic, leukoplakia, erythrolakia, submucosal, cystic, malignant appearance and fibrotic appearance.  
The routine instructions following an oral biopsy procedure include contacting the clinic regarding any questions and to return if experiencing any symptoms. All patients with at least 3 months of pain at the biopsy site were examined and details of pain characteristics were recorded. The criteria used for chronic post traumatic pain was based on ICHD-3 [4].  
Exclusion criteria for chronic pain following biopsy (II): (1) Pain due to local pathology (such as: dental, masticatory muscles, TMJ, salivary glands, maxillary sinus), (2) pain that from major surgery in the same area as the biopsy, e.g., squamous cell carcinoma removal, (3) pain from the underlying pathology such as lichen plants that was not due to the biopsy itself (these patients were included in the total 695), (4) patients with other pain diagnoses such as migraine symptomatology fulfilling ICHD criteria [4], or suspected trigeminal autonomic cephalgias (TACs) or intra cranial pathology. Additional data recorded for patients diagnosed with PPTTN after the biopsy included pain onset, pain duration, pain intensity, whether the pain is constant or intermittent or both, need for analgesics and treatment recommendations.  
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Location of the Biopsy** & **Percent (\%)** & **Number (N)** \\ \hline Buccal mucosa & 31.00\% & 216 \\ Gingiva & 21.20\% & 148 \\ Tongue & 19.60\% & 137 \\ Lips & 18.80\% & 131 \\ Hard/soft palate & 6.50\% & 45 \\ Floor of the mouth & 1.40\% & 10 \\ Retro molar pad & 0.90\% & 6 \\ Vestibule of mouth & 0.10\% & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The distribution of oral cavity biopsies by location.  
Descriptive analysis was used for qualitative variables and presented as absolute numbers and percentages. There was no need for comparative statistics. SPSS software version 22.0 was used.